Medicine

# Ternopil state medical university

Electric and magnetic properties of tissues.

MAGNETIC FIELD

Between driven electrical charges or currents in explorers the special forces which are distinct from forces, working between motionless charges work. The kind of a matter, by means of which carry out this interaction, refers to as as a magnetic field.

The force working in a magnetic field on a single driven charged particle, for example electron, refers to as as force Lorenz, it can be defined, using the law of Amper:

Force dF, from which the field works on the element, placed in him, of a current Idl (where F - force of a current and dl - element of length of an explorer), on size is directly proportional to a magnetic induction In, element of a current Idl and sine of a corner ф between them:

dF = kBIdlsin φ.

In SI factor of proportionality k - 1. On a direction the force dF is perpendicular the planes which has been carried out through vectors of a magnetic induction In and an element of a current Idl (a rule of the left hand).

From the formula follows, that at φ = 0 or φ = 180˚ force F = 0, the magnetic field does not render action on a current directed along an axis of a field.

Let's remind, that the basic characteristic of a magnetic field is the magnetic induction B - vector size, which numerical value defines on force F, working in a homogeneous field on an explorer of length l, streamline current I and located perpendicularly to vector В:

B =

The direction of a vector of a magnetic induction coincides with a direction indicated North Pole of a magnetic pointer placed in the given point of a field.

The unit of measurements in SI - Tesla (Т) - magnetic induction of a homogeneous field, which on a site of a rectilinear explorer of length 1 m, located perpendicularly to direction of a field, works with force 1 Н at course on an explorer of a constant current with force 1 А.

The magnetic field is represented by system of lines of a magnetic induction, or power lines, (Imagined curve), tangents  to which in any points specify a direction of vectors of a magnetic induction. The field, which magnetic induction in all points is identical, refers to as homogeneous and represent parallel, in regular intervals distributed power lines. Such field is formed, for example, the long solenoid inside suffices.

Magnetic fields are produced by electric currents, which can be macroscopic currents in wires, or microscopic currents associated with electrons in atomic orbits. The magnetic field B is defined in terms of force on moving charge in the Lorentz force law. The interaction of magnetic field with charge leads to many practical applications. Magnetic field sources are essentially dipolar in nature, having a north and south magnetic pole.

Figure 4.

# Magnetic Properties of Solids

Materials may be classified by their response to externally applied magnetic fields as diamagnetic, paramagnetic, or ferromagnetic. These magnetic responses differ greatly in strength. Diamagnetism is a property of all materials and opposes applied magnetic fields, but is very weak. Paramagnetism, when present, is stronger than diamagnetism and produces magnetization in the direction of the applied field, and proportional to the applied field. Ferromagnetic effects are very large, producing magnetizations sometimes orders of magnitude greater than the applied field and as such are much larger than either diamagnetic or paramagnetic effects.

The magnetization of a material is expressed in terms of density of net magnetic dipole moments in the material. We define a vector quantity called the magnetization M by

Then the total magnetic field B in the material is given by

where μ0 is the magnetic permeability of space and B0 is the externally applied magnetic field. When magnetic fields inside of materials are calculated using Ampere's law or the Biot-Savart law, then the μ0 in those equations is typically replaced by just μ with the definition

where Km is called the relative permeability. If the material does not respond to the external magnetic field by producing any magnetization, then Km = 1. Another commonly used magnetic quantity is the magnetic susceptibility which specifies how much the relative permeability differs from one.

Magnetic susceptibility:

For paramagnetic and diamagnetic materials the relative permeability is very close to 1 and the magnetic susceptibility very close to zero. For ferromagnetic materials, these quantities may be very large.

Another way to deal with the magnetic fields which arise from magnetization of materials is to introduce a quantity called magnetic field strength H . It can be defined by the relationship

and has the value of unambiguously designating the driving magnetic influence from external currents in a material, independent of the material's magnetic response. The relationship for B above can be written in the equivalent form

H and M will have the same units, amperes/meter.

Ferromagnetic materials will undergo a small mechanical change when magnetic fields are applied, either expanding or contracting slightly. This effect is called magnetostriction.

# Diamagnetism

The orbital motion of electrons creates tiny atomic current loops, which produce magnetic fields. When an external magnetic field is applied to a material, these current loops will tend to align in such a way as to oppose the applied field. This may be viewed as an atomic version of Lenz's law: induced magnetic fields tend to oppose the change which created them. Materials in which this effect is the only magnetic response are called diamagnetic. All materials are inherently diamagnetic, but if the atoms have some net magnetic moment as in paramagnetic materials, or if there is long-range ordering of atomic magnetic moments as in ferromagnetic materials, these stronger effects are always dominant. Diamagnetism is the residual magnetic behavior when materials are neither paramagnetic nor ferromagnetic.

Any conductor will show a strong diamagnetic effect in the presence of changing magnetic fields because circulating currents will be generated in the conductor to oppose the magnetic field changes. A superconductor will be a perfect diamagnet since there is no resistance to the forming of the current loops.

# Paramagnetism

Some materials exhibit a magnetization which is proportional to the applied magnetic field in which the material is placed. These materials are said to be paramagnetic and follow Curie's law:

Where С – Сurie’s constant, T – temperature, M – magnetization, B -  magnetic field.

All atoms have inherent sources of magnetism because electron spin contributes a magnetic moment and electron orbits act as current loops which produce a magnetic field. In most materials the magnetic moments of the electrons cancel, but in materials which are classified as paramagnetic, the cancelation is incomplete.

# Ferromagnetism

Iron, nickel, cobalt and some of the rare earths (gadolinium, dysprosium) exhibit a unique magnetic behavior which is called ferromagnetism because iron (ferric) is the most common and most dramatic example. Samarium and neodynium in alloys with cobalt have been used to fabricate very strong rare-earth magnets.

Ferromagnetic materials exhibit a long-range ordering phenomenon at the atomic level which causes the unpaired electron spins to line up parallel with each other in a region called a domain. Within the domain, the magnetic field is intense, but in a bulk sample the material will usually be unmagnetized because the many domains will themselves be randomly oriented with respect to one another. Ferromagnetism manifests itself in the fact that a small externally imposed magnetic field, say from a solenoid, can cause the magnetic domains to line up with each other and the material is said to be magnetized. The driving magnetic field will then be increased by a large factor which is usually expressed as a relative permeability for the material. There are many practical applications of ferromagnetic materials, such as the electromagnet.

Ferromagnets will tend to stay magnetized to some extent after being subjected to an external magnetic field. This tendency to "remember their magnetic history" is called hysteresis. The fraction of the saturation magnetization which is retained when the driving field is removed is called the remanence of the material, and is an important factor in permanent magnets.

All ferromagnets have a maximum temperature where the ferromagnetic property disappears as a result of thermal agitation. This temperature is called the Curie temperature.

Ferromagntic materials will respond mechanically to an impressed magnetic field, changing length slightly in the direction of the applied field. This property, called magnetostriction, leads to the familiar hum of transformers as they respond mechanically to 60 Hz AC voltages.

# Biot-Savart Law

The Biot-Savart Law relates magnetic fields to the currents which are their sources. In a similar manner, Coulomb's law relates electric fields to the point charges which are their sources. Finding the magnetic field resulting from a current distribution involves the vector product, and is inherently a calculus problem when the distance from the current to the field point is continuously changing.

See the magnetic field sketched for the straight wire to see the geometry of the magnetic field of a current.

Magnetic field of currerent element

where - infinitesmal length of conductor  carrying electric current I,    - unit vector to specify direction of the vector distance r from the current to the field point.

# Magnetic field contribution of a current element

Each infinitesmal current element makes a contribution to the magnetic field at point P which is perpendicular to the current element, and perpendicular to the radius vector from the current element to the field point P.  is the magnetic field contribution at P from the current element . The relationship between the magnetic field contribution and its source current element is called the Biot-Savart law.

The direction of the magnetic field contribution follows the right hand rule illustrated for a straight wire. This direction arises from the vector product nature of the dependence upon electric current.

# Lorentz Force Law

Both the electric field and magnetic field can be defined from the Lorentz force law:

The electric force is straightforward, being in the direction of the electric field if the charge q is positive, but the direction of the magnetic part of the force is given by the right hand rule.

Figure 9.Right Hand Rule

Figure 10.

The right hand rule is a useful mnemonic for visualizing the direction of a magnetic force as given by the Lorentz force law. The diagrams above are two of the forms used to visualize the force on a moving positive charge. The force is in the opposite direction for a negative charge moving in the direction shown. One fact to keep in mind is that the magnetic force is perpendicular to both the magnetic field and the charge velocity, but that leaves two possibilities. The right hand rule just helps you pin down which of the two directions applies.For applications to current-carrying wires, the conventional electric current direction can be substituted for the charge velocity v in the above digram.

# A circuit with inductance and capacity

Variable name a current, which instant values periodic change on size and on a direction. In this case instant values of a voltage u or current i are defined by the following expressions:

or

where ,  - maximal value of a voltage and current;  - circular frequency.

Let's remind, that in engineering an alternating current characterize effective values of a voltage U and current I in which the scales of measuring devices are graduated also.

The oscillatory movement of charges brings in a numberof essential differences to the phenomena occurring in circuits of an alternating current (compared with a constant current). For example, the condenser is an explorer for an alternating current; in a circuit of an alternating current containing inductance, constantly works variable EMF of a self-induction; in a circuit to a solution electrolit  there is no electrochemical polarization, and  item.

The resistance R as metal explorers (or electrolit’s solutions ) in a circuit of an alternating current refers to as active, as in it there is an irreversible loss of energy. In a circuit with active resistance is carried out the Om’s law:

Figure 11.

In a circuit with the coil of inductance L (which active resistance is possible to neglect) is formed alternating current  and is encreased the EMF of a self-induction which equate

The instant values of force of a current are defined from a condition:

or

Transforming

or

Integrating these equations

where

Constant integration C = 0 because  the current has no a constant component.

The equation shows, that the current in a circuit, similarly to the enclosed voltage, has sine wave character, but on a phase is late in relation to it on a angle π/2. It is connected to inductance of a circuit, which, similarly to inertia in mechanical system, counteracts change of instant values of a current according to change of instant values of a voltage.

Comparing the maximal value of a current   with the formula of the Om’s law  we see, that in a circuit with inductance value of resistance there is a size wL, which is designated , , refers to as inductive.

The physical sense of inductive resistance is, that it takes into account influence on force of a current in a circuit E. M. F of a self-induction, counteracting  to the enclosed voltage.

In a circuit containing and active R and inductive XL resistance, the angle φ of delay on a phase of a current can has the values from 0 to π/2.

Figure 12.

Let's consider a circuit containing the condenser with capacity C (which active resistance can be neglected) to which the variable voltage is enclosed. The instant values of charge q on the plates of the condenser:

Differenting this equation we have got:

Where

The equation shows, that the current in a circuit, similarly to the enclosed voltage, has sine wave character, and outstrips a voltage on a phase on a angle π/2. Comparing the maximal value of a current Im with the formula of the Om’s law, we see, that in a circuit with capacity value of resistance there is a size 1/ωС, which is designated Хс, refers to as as capacitor resistance to a circuit.

In a circuit containing as capacitor Хс, and active resistance R, the angle φ of shift of a phase is defined from a condition tg φ= Xc/R and can matter from 0 up to π/2,

It is possible to explain the processes occurring in a circuit during one period of an enclosed voltage. We admit, as the initial moment instant value of a voltage is maximum, the condenser is charged with polarity of plates and the instant value of a current is equaled to zero. At decrease of instant values of a voltage the condenser begins to be unloaded and in a circuit there is a current ic. Through a quarter of the period the voltage is reduced up to zero, the current reaches a maximum. Then the enclosed voltage changes a mark and supports a current in the same direction, which now charges the condenser, but at return polarity of plates. Through half of period the current i is reduced up to zero, the condenser is charged, the voltage is maximum and item.

The considered process allows to explain and physical sense of capacitor resistance. The force of a current  in a circuit of the condenser is proportional to a charge q and frequency ν of change of a charge and category of the condenser. The charge q at the given enclosed voltage also is proportional to capacity From the condenser, and the frequency v of change of a charge is proportional ω = 2nν. Therefore force of a current in a circuit is proportional to product ωС, which, hence, matters of conductivity of a circuit.

# Complete resistance to a circuit. A resonance in electrical circuits

Let's consider a circuit from the included consistently resistance: active R, inductive XL and capacitor Хс, - to which the variable voltageU enclosed. In a circuit the generalcurrent I is formed, and the enclosed voltage U is allocated between sites of a circuit: UR = IR; UL = IXL and Uc = IXc.

The voltage UL and Uc have everyone a difference of phases with a current I, equal π/2, but opposite on a mark. They are among themselves in counterphase  and, hence, can put algebraic: Ux = UL – Uc.  The  voltage UR is in a phase with a current Iand, hence, has a difference of phases π/2 with a voltage Ux.  Then the voltage U can be submitted as hypotenuse of a rectangular triangle, катетами which are UR and Ux and is calculated under the formula refers to as as complete resistance or impedance of a circuit:

The ratio I= refers to as the generalized Om’s law for a circuit of an alternating current.

The difference of phases between the enclosed voltageU and current I is defined by a angle between vectors U. For its definition it is possible to construct a triangle of resistance.

For a circuit from in parallel included of active, inductive and capacitor resistance it is possible give the following parity.

We pass to the phenomenon of a resonance. From the formula for complete resistance Z of a circuit, in which are consistently included R, L and C, blows, that than closer on size XL and Хс than the less complete resistance Z and, hence, the more current I in a circuit at the same enclosed voltage. When XL=XC  or wL=1/wC, complete resistance Z = R and the current achieves the greatest value caused only by active resistance of a circuit:

Ires=

This phenomenon name as an electrical resonance. The condition of a resonance can be supplied by selection appropriate L and C at the given frequency w refers to as resonant (or own) frequency of an electrical circuit. From a condition:

We have got:

and

,

Resonance in a consecutive circuit name as a resonance of voltage, as thus each of voltage UL and UC can considerably exceed on size the voltage, enclosed in a circuit, U.

# The resonance can take place also in a circuit from in parallel included of active, inductive and capacitor resistance, to which the voltage U is enclosed. This phenomenon refers to as resonance of currents.

###### Maxwell's Equations

Maxwell's equations represent one of the most elegant and concise ways to state the fundamentals of electricity and magnetism. From them one can develop most of the working relationships in the field. Because of their concise statement, they embody a high level of mathematical sophistication and are therefore not generally introduced in an introductory treatment of the subject, except perhaps as summary relationships.

These basic equations of electricity and magnetism can be used as a starting point for advanced courses, but are usually first encountered as unifying equations after the study of electrical and magnetic phenomena.

Integral form in the absence of magnetic or polarizable media:

Where E – electric field, q – charge density, i – electric current, B – magnetic field, μ0permittivity, J – current density, D – electric displacement, c – speed of light, H – magnetic field strength, M – magnetization, P – polarization.

Electrophoresis is the motion of dispersed particles relative to a fluid under the influence of a spatially uniform electric field. This electrokinetic phenomenon was observed for the first time in 1807 by Reuss, who noticed that the application of a constant electric field caused clay particles dispersed in water to migrate. It is ultimately caused by the presence of a charged interface between the particle surface and the surrounding fluid.

The dispersed particles have an electric surface charge, on which an external electric field exerts an electrostatic Coulomb force. According to the double layer theory, all surface charges in fluids are screened by a diffuse layer of ions, which has the same absolute charge but opposite sign with respect to that of the surface charge. The electric field also exerts a force on the ions in the diffuse layer which has direction opposite to that acting on the surface charge. This latter force is not actually applied to the particle, but to the ions in the diffuse layer located at some distance from the particle surface, and part of it is transferred all the way to the particle surface through viscous stress. This part of the force is also called electrophoretic retardation force.

Considering the hydrodynamic friction on the moving particles due to the viscosity of the dispersant, in the case of low Reynolds number and moderate electric field strength E, the speed of a dispersed particle v is simply proportional to the applied field, which leaves the electrophoretic mobility μe defined as:

The most known and widely used theory of electrophoresis was developed in 1903 by Smoluchowski, where εr is the dielectric constant of the dispersion medium, ε0 is the permittivity of free space (C² N−1 m−2), η is dynamic viscosity of the dispersion medium (Pa s), and ζ is zeta potential (i.e., the electrokinetic potential of the slipping plane in the double layer).

The Smoluchowski theory is very powerful because it works for dispersed particles of any shape at any concentration. Unfortunately, it has limitations on its validity. It follows, for instance, from the fact that it does not include Debye length κ−1. However, Debye length must be important for electrophoresis, as follows immediately from the Figure on the right. Increasing thickness of the double layer (DL) leads to removing point of retardation force further from the particle surface. The thicker DL, the smaller retardation force must be.

Detailed theoretical analysis proved that the Smoluchowski theory is valid only for sufficiently thin DL, when particle radius a is much greater than the Debye length :

This model of "thin Double Layer" offers tremendous simplifications not only for electrophoresis theory but for many other electrokinetic theories. This model is valid for most aqueous systems because the Debye length is only a few nanometers there. It breaks only for nano-colloids in solution with ionic strength close to water

The Smoluchowski theory also neglects contribution of surface conductivity. This is expressed in modern theory as condition of small Dukhin number

Du < < 1

In the effort of expanding the range of validity of electrophoretic theories, the opposite asymptotic case was considered, when Debye length is larger than particle radius:

κa < 1.

Under this condition of a "thick Double Layer", Huckel predicted the following relation for electrophoretic mobility:

This model can be useful for some nanoparticles and non-polar fluids, where Debye length is much larger than in the usual cases.

There are several analytical theories that incorporate surface conductivity and eliminate the restriction of a small Dukhin number, pioneered by Overbeek and Booth. Modern, rigorous theories valid for any Zeta potential and often any κa stem mostly from Dukhin-Semenikhin theory. In the thin Double Layer limit, these theories confirm the numerical solution to the problem provided by O'Brien and White.

Recent molecular dynamics simulations nonetheless suggest that a surface charge is not always required for electrophoresis to occur, and that even neutral particles can migrate in an electric field due to the molecular structure of water at the interface.

Computed Tomography

Computed Tomography (CT) is a powerful nondestructive evaluation (NDE) technique for producing 2-D and 3-D cross-sectional images of an object from flat X-ray images. Characteristics of the internal structure of an object such as dimensions, shape, internal defects, and density are readily available from CT images. Shown below is a schematic of a CT system.

The test component is placed on a turntable stage that is between a radiation source and an imaging system. The turntable and the imaging system are connected to a computer so that x-ray images collected can be correlated to the position of the test component. The imaging system produces a 2-dimensional shadowgraph image of the specimen just like a film radiograph. Specialized computer software makes it possible to produce cross-sectional images of the test component as if it was being sliced.

How a CT System Works

The imaging system provides a shadowgraph of an object, with the 3-D structure compressed onto a 2-D plane. The density data along one horizontal line of the image is uncompressed and stretched out over an area. This information by itself is not very useful, but when the test component is rotated and similar data for the same linear slice is collected and overlaid, an image of the cross-sectional density of the component begins to develop. To help comprehend how this works, look at the animation below.

In the animation, a single line of density data was collected when a component was at the starting position and then when it was rotated 90 degrees. Use the pull-ring to stretch out the density data in the vertical direction. It can be seen that the lighter area is stretched across the whole region. This lighter area would indicate an area of less density in the component because imaging systems typically glow brighter when they are struck with an increased amount of radiation. When the information from the second line of data is stretched across and averaged with the first set of stretched data, it becomes apparent that there is a less dense area in the upper right quadrant of the component's cross-section. Data collected at more angles of rotation and merged together will further define this feature. In the movie below, a CT image of a casting is produced. It can be seen that the cross-section of the casting becomes more defined as the casting is rotated, X-rayed and the stretched density information is added to the image.

In the image below left is a set of cast aluminum tensile specimens. A radiographic image of several of these specimens is shown below right.

CT slices through several locations of a specimen are shown in the set of images below.

A number of slices through the object can be reconstructed to provide a 3-D view of internal and external structural details. As shown below, the 3-D image can then be manipulated and sliced in various ways to provide thorough understanding of the structure.

Basic descriptions of electric-field

The electric field arises up round any charged body, regardless of it moves or not. Power description of electric-field is a size of tension of electric-field, which equals the relation of force with which the field operates on a point charge, to the size of this charge:

 .

Direction of vector  coincides with direction of force which operates on a positive charge.

Name the relation of potential energy of charge potential of electric-field in the field  to the size of this charge :

 .

Potential is a scalar physical size which characterizes the field ability to execute work. The electrostatic field is potential, that is why work, executed the field, equals diminishing of potential energy:

 ,

where  is a difference of potentials, it is named also tension:

The difference of potentials (tension) between two points equals the relation of work which is executed by the field for transferring of charge from an initial point in eventual, to the size of charge.

Differentially connection looks like between the difference of potentials:

 .

The projection of vector of the field tension on the set direction equals speed of diminishing of potential in this direction.

If the electric field is created the system  of point charges, the field tension is equal to the vectorial sum of the tension fields, created every charge separately:

 ,

and potential of electric-field – as a sum of algebra of potentials from every charge:

 .

Principle of superposition of the fields consists herein.

Electric dipole. Weeds dipole

Name the system electric dipole from two even after a size and opposite after a sign point charges, located in the distance one from another. Description of диполя is a dipole moment – vector, even work of charge  on the shoulder of dipole :

 ,

where  is a vector, directed from negative to the positive charge (shoulder of dipole).

Potential of electric-field of point charge is in the distance  from him

 ,

where  is a relative inductivity of environment,  – the electric became.

In obedience to the law of Ohm for a complete circle

 ,

If . Consequently, the size of current does not depend on resistance of external environment. Current диполь can be characterized Therefore, by analogy with electric диполем, current dipole moment :

 ,

where  is a vector which connects the poles of dipole of “– ” and “+”

In the homogeneous leading environment of unipole creates the electric field potential of which in the remote point of the field is equal

 ,

where  is a current through unipole,  – distance to the point, potential is determined in which,  is conductivity of environment.

Determine potential of current dipole after a formula:

Consequently between current dipole and electric dipole there is a considerable analogy which is based on the general analogy of electric-field in a leading environment and electrostatic field (, ).

Physical base electrography

Electrocardiogram (EKG, ECG).

As the heart undergoes depolarization and repolarization, the electrical currents that are generated spread not only within the heart, but also throughout the body.  This electrical activity generated by the heart can be measured by an array of electrodes placed on the body surface. The recorded tracing is called an electrocardiogram (ECG, or EKG).  A "typical" ECG tracing is shown to the right.  The different waves that comprise the ECG represent the sequence of depolarization and repolarization of the atria and ventricles. The ECG is recorded at a speed of 25 mm/sec, and the voltages are calibrated so that 1 mV = 10 mm in the vertical direction. Therefore, each small 1-mm square represents 0.04 sec (40 msec) in time and 0.1 mV in voltage. Because the recording speed is standardized, one can calculate the heart rate from the intervals between different waves.

P wave

The P wave represents the wave of depolarization that spreads from the SA node throughout the atria, and is usually 0.08 to 0.1 seconds (80-100 ms) in duration.  The brief isoelectric (zero voltage) period after the P wave represents the time in which the impulse is traveling within the AV node (where the conduction velocity is greatly retarded) and the bundle of His. Atrial rate can be calculated by determining the time interval between P waves. Click here to see how atrial rate is calculated.

The period of time from the onset of the P wave to the beginning of the QRS complex is termed the P-R interval, which normally ranges from 0.12 to 0.20 seconds in duration.  This interval represents the time between the onset of atrial depolarization and the onset of ventricular depolarization.  If the P-R interval is >0.2 sec, there is an AV conduction block, which is also termed a first-degree heart block if the impulse is still able to be conducted into the ventricles.

QRS complex

The QRS complex represents ventricular depolarization. Ventricular rate can be calculated by determining the time interval between QRS complexes. Click here to see how ventricular rate is calculated.

The duration of the QRS complex is normally 0.06 to 0.1 seconds.  This relatively short duration indicates that ventricular depolarization normally occurs very rapidly.  If the QRS complex is prolonged (> 0.1 sec), conduction is impaired within the ventricles.  This can occur with bundle branch blocks or whenever a ventricular foci (abnormal pacemaker site) becomes the pacemaker driving the ventricle. Such an ectopic foci nearly always results in impulses being conducted over slower pathways within the heart, thereby increasing the time for depolarization and the duration of the QRS complex.

The shape of the QRS complex in the above figure is idealized. In fact, the shape changes depending on which recording electrodes are being used. The shape will also change when there is abnormal conduction of electrical impulses within the ventricles. The figure to the right summarizes the nomenclature used to define the different components of the QRS complex.

ST segment

The isoelectric period (ST segment) following the QRS is the time at which the entire ventricle is depolarized and roughly corresponds to the plateau phase of the ventricular action potential.  The ST segment is important in the diagnosis of ventricular ischemia or hypoxia because under those conditions, the ST segment can become either depressed or elevated.

T wave

The T wave represents ventricular repolarization and is longer in duration than depolarization (i.e., conduction of the repolarization wave is slower than the wave of depolarization). Sometimes a small positive U wave may be seen following the T wave (not shown in figure at top of page). This wave represents the last remnants of ventricular repolarization. Inverted or prominent U waves indicates underlying pathology or conditions affecting repolarization.

Q-T interval

The Q-T interval represents the time for both ventricular depolarization and repolarization to occur, and therefore roughly estimates the duration of an average ventricular action potential.  This interval can range from 0.2 to 0.4 seconds depending upon heart rate.  At high heart rates, ventricular action potentials shorten in duration, which decreases the Q-T interval.  Because prolonged Q-T intervals can be diagnostic for susceptibility to certain types of tachyarrhythmias, it is important to determine if a given Q-T interval is excessively long.  In practice, the Q-T interval is expressed as a "corrected Q-T (QTc)" by taking the Q-T interval and dividing it by the square root of the R-R interval (interval between ventricular depolarizations).  This allows an assessment of the Q-T interval that is independent of heart rate.  Normal corrected Q-Tc intervals are less than 0.44 seconds.

There is no distinctly visible wave representing atrial repolarization in the ECG because it occurs during ventricular depolarization.  Because the wave of atrial repolarization is relatively small in amplitude (i.e., has low voltage), it is masked by the much larger ventricular-generated QRS complex.

ECG tracings recorded simultaneous from different electrodes placed on the body produce different characteristic waveforms.  To learn where ECG electrodes are placed, CLICK HERE.

## Waves and intervals

A typical ECG tracing of the cardiac cycle (heartbeat) consists of a P wave, a QRS complex, a T wave, and a U wave, which is normally visible in 50 to 75% of ECGs. The baseline voltage of the electrocardiogram is known as the isoelectric line. Typically, the isoelectric line is measured as the portion of the tracing following the T wave and preceding the next P wave.

 Feature Description Duration RR interval The interval between an R wave and the next R wave: Normal resting heart rate is between 60 and 100 bpm. 0.6 to 1.2s P wave During normal atrial depolarization, the main electrical vector is directed from the SA node towards the AV node, and spreads from the right atrium to the left atrium. This turns into the P wave on the ECG. 80ms PR interval The PR interval is measured from the beginning of the P wave to the beginning of the QRS complex. The PR interval reflects the time the electrical impulse takes to travel from the sinus node through the AV node and entering the ventricles. The PR interval is, therefore, a good estimate of AV node function. 120 to 200ms PR segment The PR segment connects the P wave and the QRS complex. The impulse vector is from the AV node to the bundle of His to the bundle branches and then to the Purkinje fibers. This electrical activity does not produce a contraction directly and is merely traveling down towards the ventricles, and this shows up flat on the ECG. The PR interval is more clinically relevant. 50 to 120ms QRS complex The QRS complex reflects the rapid depolarization of the right and left ventricles. They have a large muscle mass compared to the atria, so the QRS complex usually has a much larger amplitude than the P-wave. 80 to 120ms J-point The point at which the QRS complex finishes and the ST segment begins, it is used to measure the degree of ST elevation or depression present. N/A ST segment The ST segment connects the QRS complex and the T wave. The ST segment represents the period when the ventricles are depolarized. It is isoelectric. 80 to 120ms T wave The T wave represents the repolarization (or recovery) of the ventricles. The interval from the beginning of the QRS complex to the apex of the T wave is referred to as the absolute refractory period. The last half of the T wave is referred to as the relative refractory period (or vulnerable period). 160ms ST interval The ST interval is measured from the J point to the end of the T wave. 320ms QT interval The QT interval is measured from the beginning of the QRS complex to the end of the T wave. A prolonged QT interval is a risk factor for ventricular tachyarrhythmias and sudden death. It varies with heart rate and for clinical relevance requires a correction for this, giving the QTc. Up to 420ms in heart rate of 60 bpm U wave The U wave is hypothesized to be caused by the repolarization of the interventricular septum. They normally have a low amplitude, and even more often completely absent. They always follow the T wave and also follow the same direction in amplitude. If they are too prominent, suspect hypokalemia, hypercalcemia or hyperthyroidism usually.[28] J wave The J wave, elevated J-point or Osborn wave appears as a late delta wave following the QRS or as a small secondary R wave. It is considered pathognomonic of hypothermia or hypocalcemia.[29]

Originally, four deflections were noted, but after the mathematical correction for artifacts introduced by early amplifiers, a fifth deflection was discovered. Einthoven chose the letters P, Q, R, S, and T to identify the tracing which was superimposed over the uncorrected labeled A, B, C, and D.

In intracardiac electrocardiograms, such as can be acquired from pacemaker sensors, an additional wave can be seen, the H deflection, which reflects the depolarization of the bundle of His. The H-V interval, in turn, is the duration from the beginning of the H deflection to the earliest onset of ventricular depolarization recorded in any lead.

Placement of electrodes

Ten electrodes are used for a 12-lead ECG. The electrodes usually consist of a conducting gel, embedded in the middle of a self-adhesive pad onto which cables clip. Sometimes the gel also forms the adhesive. They are labeled and placed on the patient's body as follows:

Proper placement of the limb electrodes, color coded as recommended by the American Heart Association (a different colour scheme is used in Europe): The limb electrodes can be far down on the limbs or close to the hips/shoulders, but they must be even (left vs right).

When exercise stress tests are performed, limb leads may be placed on the trunk to avoid artifacts while ambulatory (arm leads moved subclavicularly and leg leads medial to and above the iliac crest).

 Electrode label (in the USA) Electrode placement RA On the right arm, avoiding thick muscle. LA In the same location where RA was placed, but on the left arm. RL On the right leg, lateral calf muscle. LL In the same location where RL was placed, but on the left leg. V1 In the fourth intercostal space (between ribs 4 and 5) just to the right of the sternum (breastbone). V2 In the fourth intercostal space (between ribs 4 and 5) just to the left of the sternum. V3 Between leads V2 and V4. V4 In the fifth intercostal space (between ribs 5 and 6) in the mid-clavicular line. V5 Horizontally even with V4, in the left anterior axillary line. V6 Horizontally even with V4 and V5 in the midaxillary line.

The classical 12-lead ECG can be extended in a number of ways in an attempt to improve its sensitivity in detecting myocardial infarction involving territories not normally "seen" well. This includes an rV4 lead, which uses the equivalent landmarks to the V4 but on the right side of the chest wall and extending the chest leads onto the back with a V7, V8 and V9.

The Lewis lead or S5 has the LA electrode placed in the second intercostal space to the right of the sternum with the RA at the fourth intercostal space. It is read as lead I and is supposed to demonstrate atrial activity much better to aid in identification of atrial flutter or broad-complex tachycardia.

In both the 5- and 12-lead configurations, leads I, II and III are called limb leads. The electrodes that form these signals are located on the limbs—one on each arm and one on the left leg. The limb leads form the points of what is known as Einthoven's triangle.[20]

·              Lead I is the voltage between the (positive) left arm (LA) electrode and right arm (RA) electrode:

·              Lead II is the voltage between the (positive) left leg (LL) electrode and the right arm (RA) electrode:

·              Lead III is the voltage between the (positive) left leg (LL) electrode and the left arm (LA) electrode:

Simplified electrocardiograph sensors designed for teaching purposes, e.g. at high school level, are generally limited to three arm electrodes serving similar purposes.

The two types of leads are unipolar and bipolar. Bipolar leads have one positive and one negative pole. In a 12-lead ECG, the limb leads (I, II and III) are bipolar leads. Unipolar leads also have two poles, as a voltage is measured; however, the negative pole is a composite pole (Wilson's central terminal, or WCT) made up of signals from lots of other electrodes. In a 12-lead ECG, all leads besides the limb leads are unipolar (aVR, aVL, aVF, V1, V2, V3, V4, V5, and V6).

Wilson's central terminal VW is produced by connecting the electrodes RA, LA, and LL together, via a simple resistive network, to give an average potential across the body, which approximates the potential at infinity (i.e. zero):

Leads aVR, aVL, and aVF are augmented limb leads (after their inventor Dr. Emanuel Goldberger known collectively as the Goldberger's leads). They are derived from the same three electrodes as leads I, II, and III. However, they view the heart from different angles (or vectors) because the negative electrode for these leads is a modification of Wilson's central terminal. This zeroes out the negative electrode and allows the positive electrode to become the "exploring electrode". This is possible because Einthoven's Law states that I + (−II) + III = 0. The equation can also be written I + III = II. It is written this way (instead of I − II + III = 0) because Einthoven reversed the polarity of lead II in Einthoven's triangle, possibly because he liked to view upright QRS complexes. Wilson's central terminal paved the way for the development of the augmented limb leads aVR, aVL, aVF and the precordial leads V1, V2, V3, V4, V5 and V6.

·              Lead augmented vector right (aVR)' has the positive electrode (white) on the right arm. The negative electrode is a combination of the left arm (black) electrode and the left leg (red) electrode, which "augments" the signal strength of the positive electrode on the right arm:

·              Lead augmented vector left (aVL) has the positive (black) electrode on the left arm. The negative electrode is a combination of the right arm (white) electrode and the left leg (red) electrode, which "augments" the signal strength of the positive electrode on the left arm:

·              Lead augmented vector foot (aVF) has the positive (red) electrode on the left leg. The negative electrode is a combination of the right arm (white) electrode and the left arm (black) electrode, which "augments" the signal of the positive electrode on the left leg:

The augmented limb leads aVR, aVL, and aVF are amplified in this way because the signal is too small to be useful when the negative electrode is Wilson's central terminal. Together with leads I, II, and III, augmented limb leads aVR, aVL, and aVF form the basis of the hexaxial reference system, which is used to calculate the heart's electrical axis in the frontal plane. The aVR, aVL, and aVF leads can also be represented using the I and II limb leads:

The electrodes for the precordial leads (V1, V2, V3, V4, V5 and V6) are placed directly on the chest. Because of their close proximity to the heart, they do not require augmentation. Wilson's central terminal is used for the negative electrode, and these leads are considered to be unipolar (recall that Wilson's central terminal is the average of the three limb leads. This approximates common, or average, potential over the body). The precordial leads view the heart's electrical activity in the so-called horizontal plane. The heart's electrical axis in the horizontal plane is referred to as the Z axis.

The last ECG leads to consider are the precordial, unipolar chest leads.  These are six positive electrodes placed on the surface of the chest over the heart in order to record electrical activity in a plane perpendicular to the frontal plane (see figure at right). These six leads are named V1 - V6.  The rules of interpretation are the same as for the limb leads.  For example, a wave of depolarization traveling towards a particular electrode on the chest surface will elicit a positive deflection.

In summary, the twelve ECG leads provide different views of the same electrical activity within the heart.  Therefore, the waveform recorded will be different for each lead.  To understand how cardiac electrical currents actually generate and ECG tracing and why the different leads display that electrical activity differently, it is necessary to understand volume conductor principles and vectors

The difference of potentials, which are registered at Electrocardiography, turns out at excitation nerves - muscles of device of heart. Nervous or muscles the fibers in a condition of rest is polarized so, that the external surface of its environment has a positive charge, and internal negative. At excitation this difference of potentials sharply decreases, and then changes a mark to opposite. In process of passage of a wave of excitation along a fibers the difference of potentials on its sites comes back to initial state.

The device is included between an external surface of an environment and internal environment of a fiber, will register change of potentials shown on a

The part of a curve (a) answers a phase "depolarization", part (b) - "repolarization" of an environment and part (c) - "remain" to potential. The phenomenon as a whole name as formation" of potential of action ".

Biopotentials, sum on all elements nervously - muscles of the device, form a common difference of potentials, which refers to as electromotive force of heart.

The size of the loops is determined in mm from a zero line to upwards for positive P, R, and T, and downwards - for negative Q, S and is compared with calibrated by a signal, which the voltage U = 1mV determined. Size greatest loops R: UR=2,5mV. The duration loops and intervals of absence of a signal is determined on a special grid located on electrocardiograms. All intimate cycle lasts approximately 1c, and most short-term loops - 100-th shares of second. Thus, electrocardiograph should register a difference of potentials with frequency from 0,3 up to 120-150 Hz and amplitude about 1mV. It requires amplification biopotentials in tens thousand times.

There are many different marks electrocardiograph we shall work with Cardio complex. A principle of action electrocardiograph based on direct amplification and registration as a curve (electrocardiograms) of a voltage of signals from electrodes of the body, imposed on the appropriate point, of the patient. The electrodes join to electrocardiographs through a cable of loops, which consists of conductors, which correspond  to number of electrodes, and come to an end by probes with multi-colored cables. The display of the information can be on the monitor of computers or can be printed out on a paper.

Considered us loops are basic. In the further number loops was increased at the expense of electrodes, which are imposed on a surface thorax of a crate in the field of an arrangement of heart. These loops correspond to a projection of a vector electric of force of heart a horizontal plane.

Medical equipment for mesument electrical signals of heart.

## High resolution 16-channel ECG system

A CE-certified Reference-Electro-Cardiogram-Device (ECG-device) providing a number of special technical features has been developed and manufactured by the Physikalisch-Technische Bundesanstalt (PTB). The system records and stores bio-electrical potential differences at the body surface caused by the excitation of the heart.
In contrast to common ECG-systems the reference ECG-device stores the potential differences measured with respect to a reference electrode. There is no hardware lead network. The conventional ECG is calculated exactly by software.
This approach enables the simulation of human electrical heart activity. The signal can directly be fed into the patient cables of a commercial ECG-device for testing , -also for measuring and analysing ECG-devices- The system offers the possibility to record simultaneously up to 16 channels. This allows to record the data for the standard ECG-leads, to calculate the Frank-leads as well as to acquire reference signals regarding breathing and the frequency of the main power voltage.

• Measurement device providing a total 16 channels, 14 channels for ECG's and one channel each for breathing and power voltage
• Input voltage of ±16 mV with an offset of up to ±300 mV that can be compensated
• Input impedance: 100 MOhm (DC)
• Resolution: 16 bit with 0,5 µV/LSB
• Signal band width: 0...1 kHz (synchronous sampling of all channels)
• Noise: max. 10 µV (pp) or 3 µV (rms) for short circuit at input
• Online-measurement of skin impedance before and after data acquisition
• Noise-measurement during data acquisition

Fig 1. High resolution 16-channel ECG system              Fig 2. Amplifier module of the ECG systems

Characteristics of electric current. Ohm's Law and Joule-Lenz in differential form

Electric current is called an ordered (directed) motion of electric charges. Amperage  is determined by the ratio of the charge  that is transferred through the cross section of the conductor, the length of time  over which this charge is transferred:

 (1)

If for any regular intervals transferred the same amount of electric charge, a current is called permanent. Then

 (2)

Current density  - the value of which is equal to the current  to the cross-sectional area of the conductor , through which this current passes.

 (3)

In the case of direct current

 (4)

Ohm's law in differential form:

 (5)

Current density is proportional to the electric field, and it has the same direction.  Here - resistivity,  - electrical conductivity.

Ohm's law in this way establishes a link between the local variables that are relevant to a given point of the conductor, so it is applicable to inhomogeneous conductors.

Skip electric current through biological tissue is accompanied by heating. The amount of heat that is released at the same time

 (6)

Heat capacity per unit volume:

 (7 )

These formulas express the Joule-Lenz in differential form.

Electrical conductivity of tissues. Galvanization and electrophoresis treatment

Many biological media are electrolytes. Carriers in electrolytes are positively and negatively charged ions that result from electrolytic dissociation.

The directed movement of ions in the electrolyte can be considered uniform, and the electric force is balanced with the force of friction

 , , (8)

where  - coefficient of friction - velocity of the ion. Then

 , (9)

where - the mobility of ions.

The mobility of ions  numerically equal to the velocity of ordered motion in the electric field of strength , .

The electrical conductivity of electrolytes is given by

 (10)

Here - the coefficient of electrolytic dissociation - ion concentration.

Current density in the electrolyte is:

 (11)

Electrical conductivity of tissues and organs depends on their functional status, and is used as a diagnostic indicator.

Measurement of electrical conductivity (conductometry) is widely used in the study of processes that occur in living cells and tissues in the physiological state changes as a result of certain chemical substances, and provided pathological processes.

The primary effect of direct current on the body due mainly to two processes: polarization tissues of the body and movement and redistribution of charged particles in the body. These processes cause a change in the functional state of cells, ie, excitation or inhibition of their activities. A reflex neurohumoral or regulatory mechanisms that lead to functional changes in the relevant tissues and organs, which is the basis of therapeutic effect.

Apply a small DC power (50 mA) and voltage of 30-80 V with the purpose of treatment is called galvanization. In this case, the current density should not exceed . Introduction to the tissues medical substance  by therapeutic constant current called electrophoresis.

Galvanization. Therapeutic electrophoresis

Medical electrophoresis - combined effect of direct electric current and the medical substance  substance administered with it. This method is related to the ability of complex substances in a solvent dissociate into positive and negative ions. In this case the ions are introduced with the same name with the electrode polarity that accumulate in the skin, forming a depot. In the skin, can be formed and tissue depot. Because of small blood supply to the skin depot ion dissolves slowly, providing a constant supply of the medical substance  into the bloodstream. By doing Although the number of medical substance  in the blood with this method is small, but high local concentration, increased electrical activity of ions and biophysical and biochemical changes in the tissues caused by direct current, contribute marked pharmacological effect.

Fig.1. Conducting electrophoresis procedure.

Electrophoresis to minimize side effects the medical substance  because the fabric are introduced only needed his constituents. Jonah medical substance  cause irritant nerve receptors of the skin, which leads to the formation through the central nervous system reflex ion, specific for the substance. In medical actions electrophoresis, except the DC parameters are relevant placements of electrodes and the area of the functional state of the organism, and pharmacological properties of the medical substance , its concentration, individual sensitivity to human medical substance  and electricity.

Fig.2. Conducting galvanization procedure.

The concentration of the medical substance  is of great practical importance. It is known that the linear dependence of the number entered on the concentrations of ions is only at low concentrations of solutions. Therefore electrophoresis recommend the use of 2-6% solutions of medical substance s, the optimal concentration for most substances is in the range 1-3%. Electrophoresis advantage is the fact that it can be used to enter the medical substance  in tissues inaccessible to other routes of administration. Contraindications to the appointment of galvanization and electrophoresis are acute inflammation, especially pus, processes, malignancies, cardiac decompensation, marked cerebral sclerosis, epilepsy, acute skin diseases, toxic condition, tendency to bleed, individual intolerance and pharmacological contraindications for the purpose of a medical substance .

STRUCTURAL PATTERN AND APPARATUS EQUIPMENT

galvanization and electrophoresis “STREAM 1”

Fig.3.  Apparatus for galvanization and electrophoresis STREAM-1.

Fig.4. Electrical schematic diagram of the apparatus STREAM 1.

Apparatus of galvanization and electrophoresis, are offered on the world market

Fig.5. Apparatus for electrotherapy channel "customs eF2."

Fig.6. Analytical electrophoresis ITU-202 model for the analysis of  DNA/RNA.

Fig.7. Apparatus for galvanization and electrophoresis ELFOR.

Technique and methods of electroplating and electrophoresis.

Before the procedure, the skin in the areas of action for the removal of fat and flaky epidermis rubbed with a wet swab. If the defect skin or mucous membrane of this part isolated piece of cloth or cellophane to avoid burns. The skin or mucosa impose electrodes consisting of a metal plate and gasket thickness greater than 1 cm, dampened with warm tap water. Through electrodes connected via terminals to wires going to the terminals of the apparatus for electroplating . In pathological focus is usually impose an active electrode area of less than indifferent . Apply lateral and longitudinal location of the electrodes. At the cross - active and indifferent electrodes impose parallel to each other so that the pathological focus was in the interelectrode space and buckling - placing electrodes in the same plane along the abnormal cell. When electrophoresis between the skin and electrode pad placed filter paper or 2-3 layers of gauze , soaked 1-5 % solution of the medical substance  . To make things simple medicinal substance moistened pad directly by following the procedure discarded. If you need to check the polarity of the terminals of the device galvanization wire clamps applied to a piece of cotton wool soaked in a solution of potassium iodide and passed an electric current strength of 1-5 mA. It appears at the anode brown staining due to the evolution of iodine. After the procedure, the external electrode pads washed and sterilized by boiling , and the metal plate is treated with alcohol and boil .

Galvanization and electrophoresis of medical substance  dosing in current density (the number of current active electrode area 1), time and number of procedures per treatment. Therapeutic current density in the oral cavity is 0.1-0.5 mA / children 0.05 mA / time of 20-30min, per treatment and 30 treatments.

Types of Procedures:

Effect on the nasal mucosa.

Two nasal electrodes converted them with a cotton swab is introduced as deeply as possible into the nasal passages and attach to terminal apparatus. Tampons should be tightly contact with the mucous membranes of the nasal passages. Indifferent electrode placed in the upper cervical vertebrae, if the anode, and lower cervical vertebrae, if the cathode.

Transverse effects on the temporomandibular joint.

Electrode size 4x5 cm impose on the affected joint. Second, the mouth, the tip of the active electrode area of 2 is introduced with an open mouth in a pear-shaped triangle. Current density up to 0.3 mA/.

Effects on sympathetic cervical nodes.

Two electrodes 3x6 cm size imposed along the front edge of the sternum-clavicular-mastoid muscle. United end conductors connected to one terminal of the device. The other electrode is attached 6x8 cm, located in the upper cervical vertebrae, if the anode, and lower cervical vertebrae, if the cathode. Current density of 0.1 mA/.

General galvanization/

The electrode area of 300 - in the blade area, the other two, each measuring 150 - placed on the calf muscles. Leaders of the two electrodes connect together and connected to the terminal device. Current intensity of 10 mA.

Action on the face.

Three-bladed electrode ("half-mask Bergonie") of 200 put on one half of the face, the second electrode of the same area is placed on the opposite shoulder. Amperage to 5 mA.         Effects on facial neuritis with facial and auditory nerves.

In the external auditory canal side porazhennya introduce a cotton swab moistened with medical substance s. Then impose electrode - "respirator Bergonie" of 200. End swab should contact electrode. The second electrode of the same area is placed on the opposite shoulder. Current density of 0.1 mA /.

Effects on trigeminal nerve exit point.

Three circular electrodes with a diameter of 4 cm is placed on the skin projection supraorbitalnoho, infraorbitalnoho and mental holes. Connecting conductors with their ends connected to one terminal of the device. The other terminals attached electrode with an area equal to the area of the three first applied to 0.5 cm in front of the ear by a projection of the trunk of the nerve.

Methods of electrophoresis.

Fig.9. Ingestion medical substance in the tissue.

There are three main methods of administration of medical substance into the human body by means of direct current.

1. The most widely used introduction of drugs from solutions in which wet hydrophilic spacers placed between the metal electrode and the human body. These pads are made of flannel, calico, gauze or filter paper. Hydrophilic gasket should be of sufficient thickness (16 layers of flannel or calico). Filter paper (2-8 layers) are the introduction of potent or toxic substances when they are administered in a small area of the site. Dampened with a solution medical substance should be dry, not wet pad. Otherwise dramatically reduced the concentration of the solution medical substance, which could significantly change the conditions of its introduction by constant current.

2. Introduction of medicinal substances from solutions that fit between the electrode and the human body. For this purpose, most often used baths, into which poured a solution of medical substance dropped a metal (or carbon) electrode connected to the corresponding pole of the current source. The solution medical substance can be administered in either the cavity of the body. In the same cavity input electrode coupled to the current source. There are special devices that provide continuous flow and removing fluid from a cavity subjected to electrophoresis [vnutrishnovahinalnyy electrophoresis, electrophoresis in the cavity of the rectum, and others.].

3. Much more difficult is the technique of administration to cells or preferential deposition on a particular area of the human body of drugs circulating in the blood. To do this, after the introduction of one or the other way drugs with hydrophilic electrode pads moistened with tap water or weak brine, placed on the human body in such a way that part of the body located between the electrodes. Under these conditions, an increase in the lumen of the capillaries and increased permeability of the capillary wall under the influence of other billeting promote the flow of current in the tissue gap increased amounts of medicinal substances circulating in the blood. Direction medical substance movement in the electric field is determined by the appropriate placement of electrodes connected to the positive or negative pole of the power source.

Location electrode with hydrophilic spacers, their size and shape, as well as the drug substance, administered, defined therapeutic task. For example, electrophoresis medical substance in the region of the trigeminal or facial nerve produced by an electrode that has three tabs. In cases where the subject of the area just two branches of substances in the region

trigeminal nerve, electrode shape changes accordingly. If the drug substance is introduced only in the exit area of the trigeminal nerve, the electrode is shaped correctly quadrilateral or circle the appropriate size. To enter the drugs used in the eye bath with a metal electrode. Bath is filled to the brim with a solution medical substance to be administered. Land baths zmauyut thick Vaseline. The second electrode is applied to the upper back.

For the electrophoresis (intranasal ionogalvanizatsiya general) are widely used large electrodes. One of them, 15X20sm size, placed in the blade area and the other two, size 10x20 cm, are placed on the dorsal surface of the tibia. Power adapter with this technique electrophoresis to 30 mA, duration of treatment 20-30 minutes. In this way, I can not enter into the human body large quantities of drugs from the calculation of their overall performance.

There is a practice of introducing drugs into collar area to obtain terapevtychnotsinnyh reflexes caused innervation feature of this area. Electrode in the shape of a collar with an appropriate hydrophilic pad area of 800 cm2, superimposed on the collar area, which has a rectangular shape of the surface of 400 cm2, placed in the lumbosacral region. Duration of treatment (voltaic collar) from 6 min, as well as the amperage from 6 mA, gradually increased, bringing to 16 min and 16 mA. With the use of this technique for electrophoresis of drugs amperage and duration used much larger.

When electrophoresis of drugs in the area of wounds and ulcers advance their surface thoroughly cleaned and rinsed with hydrogen peroxide, then covered with several layers of gauze moistened with a solution medical substance, over which is superimposed hydrophilic lining of several layers of flannel moistened with water or 1% solution of salt. The second electrode is placed so that the current passed through the wound in the transverse direction.

Electrical anesthesia constant electric current.

Analgesic effect of direct electric current associated with the development of tissues elektrotonu phenomena that cause nerve excitability change during the passage of current. It is believed that while at the cathode increases excitability to stimulation, and at the anode - is reduced.

Due to the physical and physiological phenomena elektrotonu elektroznebolennya used for DC both positive and negative pole, but prefer positive as adequate stimuli. However, there is evidence that cathode znebolyuye better than the anode.

For pain relief to find amperage that will lead to the blocking pain impulse. It is believed that the optimum parameters of current with direct action on nerve receptors range from 10 to 20 mA.

Types of electrophoresis.

There are three types of electrophoresis: front, zonal and continuous.

In frontal electrophoresis macromolecules found throughout the bulk solution and the mobility determined by shlirenovskoyi optics as a function of time. This analytical method, it is used to determine the isoelectric point of polymeric molecules such as proteins, nucleic acids, and so on. For electrophoretic separation, this method is used only in rare cases.

When zonal electrophoresis sample micropipette applied as spots or stripes (zones) on the surface of the carrier and move microparticles in solution at different rates according to their electrophoretic properties. The method used for the separation of mixtures, purity determination and analysis of changes in mobility and (or) the conformation of macromolecules as well as for high-quality cleaning agents.

With continuous electrophoresis sample was also applied as a band, but it'll add time.

Methods zonal electrophoresis.

Since the zonal electrophoresis sample is applied to a solid or gelatinous (semi-) media in a zone, the conditions for complete separation to use a small amount of starting material. This circumstance requires such a carrier that best prevents mechanical stress and convection processes arising from temperature fluctuations and high concentration of molecules in the sample solution. Under certain conditions the media can adsorb molecules of different types or act as a molecular sieve, thereby leading to chromatographic effects or manifestation of processes electroosmosis. These properties may contribute to the separation medium, or impair it, depending on the physico-chemical properties of molecules of the sample and buffer properties of the medium. The use of different materials as a carrier and under different procedures for separation characterizes different types of zonal electrophoresis as follows:

1. Electrophoresis on paper;

2. Electrophoresis on cellulose acetate;

3. Thin-layer electrophoresis.

4. Gel electrophoresis.

Electrophoresis on paper.

Electrophoresis on paper the most easy and affordable method of separation. Equipment needed for this electrophoresis consists of two parts: the power supply and the actual electrophoretic unit. The power supply is stabilized dc generator and a control system of voltage and current output. For low-voltage electrophoresis on paper using the output voltage to 500 V and amperage of 150 mA.

In electrophoretic unit includes electrodes, buffer chamber, support for media-paper, camera and water to maintain humidity and transparent insulating cover.

Special paper electrophoretic not exist for electrophoresis using chromatographic paper. Strips of paper cut to measure , moistened with buffer and placed on the insulation plate electrophoretic unit. On paper micropipette applied such as spots or lines. Building block close lid , give the appropriate voltage to the electrodes and produce separation. In the process of separation is necessary to maintain a given level of stress , and monitor the temperature of the environment , preventing overheating . After separation , after switching off the supply voltage , the paper is removed and dried. Low voltage electrophoresis is carried out within 1-2 hours. Further, the separated substances to distinguish from paper, to identify and carry out their qualitative or quantitative analysis. To do this, use the same methods as in paper chromatography . Localization separated substances on paper showing through dyes with different functional groups provide some sample components characteristic color . " Spots " with separated substances on paper cut and carry their respective extraction solvents. Extracts substances can be quantitatively analyze different methods: spectrophotometric, radiometric potentiometrically or if substances containing radioactive label.

Electrophoresis on cellulose acetate.

Most organic molecules adsorbed on the fibers of the paper through the hydroxyl groups of cellulose. Prevents adsorption of particles and causes stretching spots, which greatly affects the process of separation of sample components. These negative effects can be removed if instead of paper using cellulose acetate membrane. In cellulose acetate cellulose hydroxyl groups converted to acetate, which do not exhibit adsorption properties. This improves the quality of separation, increases the rate of separation process and allows you to use a lower voltage for electrophoresis. Methodically electrophoresis on cellulose acetate conducted so as electrophoresis on paper.

It should also be noted that the high solubility of cellulose acetate in various solvents and its transparency can easily extract separated components and identify these substances spectrophotometrically.

Thin-layer electrophoresis.

When the carrier serves as a thin layer electrophoresis sorbent layer thickness 0,25-0,50 mm, which is uniformly coated on a glass plate. Often used as a carrier silica or alumina. With carrier plate is placed in a horizontal electrophoresis apparatus and enable thin buffer layer be satisfied by the solution of the diffusion buffer chambers through contact paper wick. Micropipette applied to the sample and submit tension.

Thin-layer electrophoresis is most often used for the separation at high voltages (high-voltage electrophoresis). The method has a high resolution and high sensitivity.

Often thin-layer electrophoresis is carried out in combination with thin layer chromatography, ie, after electrophoresis, is normal to the direction on the same plate chromatography was carried out. This method was named "method vidpechatkiv fingers" and enables high-quality split complex multicomponent mixtures.

Gel electrophoresis.

The best effect is achieved separation of organic macromolecules by gel electrophoresis. As a carrier using gels with starch, agarose, polyacrylamide and agarose - acrylamide. High resolution gel carriers account for the effect of'' molecular sieve. "This is due to the reduced diffusion of particles in a grid pattern of the gel and separating gel penetrating action chromatography. Structural gels composed of randomly interwoven polymer chains that form sytopodibnu structure at around 'volume of gel. principle of molecular sieve is that large molecules will move more slowly than smaller pores in the gel structure whose dimensions are determined by the number of transverse cross-links between the polymer chains.

The most effective gel carriers believe poliarylamidni gels that combine a number of properties:

1. Pore size can vary widely.

2. Gels can be formed into calibrated containers (tubes and plates).

3. They are characterized by very low levels of adsorption and electroosmosis.

4. They can be used with different buffers.

5. The process of separation is very fast.

6. Divided substance can be determined using densitometria.

Polyacrylamide gels obtained by copolymerization of acrylamide and metylenakrylamidu in the presence of free radical catalysts. Monomers dissolved in the buffer, add catalyst and cooked mixture is poured into appropriate containers which will hold electrophoresis. The process of polymerization (gel formation) if necessary, accelerate, irradiating ultraviolet containers. Changing the buffer concentration of acrylamide from 3 to 30% can be obtained gels with pore diameters of 0.2 to 0.5 nm and thus regulate the molecular sieve effect.

Disc electrophoresis.

Disc electrophoresis is a modified gel electrophoresis on vertical columns of polyacrylamide. This method was developed for electrophoresis separation of high fractions of protein drugs. Feature of the method is that:

1. In column using electrophoretic gels with different pore size. The top layer of the gel, which is a third column is coarsely porous and it is called concentration gel. At the bottom of the column forming finely porous gel which actually is a working gel. This gradient pore size allows effective use in the separation phenomenon of molecular sieves.

2. For disc electrophoresis buffer systems are selected such that, ionizing protein molecules, transforming them into anions. Therefore, the power supply in the upper buffer chamber placed cathode, and at the bottom - the anode. Electrophoresis was carried out at a constant value of electric current within 10mA.

3. The upper and lower buffer chambers using buffer systems with different pH. In the lower chamber buffer pH 2-3 units higher than at the top. This leads to the emergence of a pH gradient along the electrophoretic columns and ionization accompanied by varying degrees of protein molecules in the concentration and operating gels.

Electrophoretic column filled with work and concentration gels, placed in the lower chamber with buffer Tris-glycine system. On the surface of the gel is applied micropipette sample and fill the buffer system of Tris-HCl upper chamber. The device close lid and submit the voltage on the electrodes.

The top layer of the gel has a high porosity, because the mobility of the protein sample anions it will be closer to their mobility in free solution. At the edge of the top and work the gel porosity decreases sharply, causing a significant reduction in the mobility of the protein plates. Consequently, the components of the sample to fit your gel in a very narrow concentrated band.

Passing the zone of your gel microparticles sample fall into something else Electrophoretic environment. First, fine-gel operating on a

molecular sieve and makroiony with greater molecular mass moving slowly. In Drut, a higher pH tris-glycine buffer causes additional ionization protein makroioniv. More ionized protein anions will have more speed. Thus, the electrophoretic mobility of protein molecules in the gel will work proportional to the ratio of charge to mass. This factor determines the high resolution disc electrophoresis.

Immunoelectrophoresis.

This method is based on the combined use of thin-layer electrophoresis and immunodiffusion method. This combination of techniques makes it possible, using precipitation reactions between antigens and corresponding antibodies separate and identify similar in electrophoretic mobility of protein molecules. The method is particularly valuable in detecting antigens in complex mixtures of physiologically active, such as drugs munohlobuliniv. The principle of the method is that the original sample separated by thin-layer electrophoresis on an agar plate. Upon termination electrophoresis groove, cut in agar, make a mixture of antibodies and maintain the time required for the passage of diffusion processes. Antibodies diffuse laterally and diffusion of antigens sample is in the radial direction. At a meeting with the appropriate antigen antibody precipitation reaction occurs, which is localized on the media in the form of curves. Number of arcs formed, corresponding to the number of investigated antigens.

Isoelectric focusing.

The basis of this method is the front electrophoresis in gradient pH. This method of separating organic amfolity such as amino acids, peptides, and others. Amfolitiv molecules containing both positively and negatively charged groups. Moreover. net charge of the molecules depends on the pH of the medium in which they are dissolved. At low pH values amfolitiv ions are predominantly positive charge, while high - mostly negative. However, for each amfolitu there is a pH at which their net charge is zero. This pH is called the isoelectric point. At the isoelectric point of the molecule amfolitiv will not move in the applied electric field to them.

The method consists in the fact that the pH gradient electrophoresis, each amfolit moves to the column area, where the pH corresponds to its isoelectric point. Reaching the area isoelectric point, molecular motion ceases and amfolitu they concentrate (focus) in this part of the column. For the formation and stabilization of the pH gradient electrophoretic column using synthetic small molecule poliamfolity which are a mixture polialifatychnyh amino and carboxylic acids.

Isoelectric focusing is carried out in a saturated solution of sucrose or coarsely porous piliakrylamidnyh gels. Gel izoelektrofokusuvannya mainly used for microanalysis of proteins. In the latter case, electrophoresis is carried out as follows: in column form krupnoporystyy electrophoretic gel. Prepare an aqueous suspension of synthetic poliamfolitiv , which have isoelectric point values that override pre- selected area of ​​pH. The column is filled with the gel suspension and cooked to a buffer connected via cameras. The upper chamber is filled with sylnokyslym buffer , and bottom - sylnoluzhnym buffer. Buffer solutions diffuse into the column and after a while the column pH gradient is established with the extreme values corresponding to acidic and alkaline pH buffer solutions. After that, the top electrode (anode ) and lower ( cathode) buffer beep tension. Under the influence of the applied voltage poliamfolity suspension migrate to the appropriate zone pH at which their net charge is zero. Further poliamfolitiv movement ceases and they are set to stabilize the electrophoretic medium pH gradient .

In this way the current column electrophoretic pattern making and begin to divide its protein components. The process of separation lasts 6-9 hours, during which time the mixture components are distributed in zones with corresponding pH values that characterize their isoelectric point. After the separation column is dried determine the localization of the protein fractions in the gel and spend their quantitative or qualitative analysis of relevant instrumental methods.

Isoelectric focusing method has some significant advantages: allows to separate proteins that other methods can not be divided, and provides a high degree of concentration in the areas of protein localization, high resolution method allows to separate proteins that differ in their isoelectric point by only 0.02 pH units.

Electrodialysis.

Electrodialysis is used to separate colloidal particles from low electrolytes. For this purpose dialysis membrane with a thickness of 10 to 1000 nm. The material for such membranes are polyester films with cellulose, polyvinyl alcohol, cellophane. Dialysis films with pore sizes ranging from 0.01 to 1.00 microns. Such films pass low-molecular compounds and macromolecular compounds pass particles. Industries also produces special ionoselective film that selectively pass or only anions (anionitni films) or only cations - (kationitni film).

Working container of ionoselective membranes filled with colloid solution that you want to clear the low-molecular ions. Filled containers are fixed on the rotor mechanical stirrer and immersed in a dialyzer with a working solution. Dialysis is carried out at a constant voltage of several hundred volts. Due to the applied voltage low ions migrate through the pores of the membrane from the colloidal solution working. High-molecular ionized particles, due to their large size, can not pass through the small pores of the membrane and remain in the container. After a certain period of time all low ions leave the colloidal solution, that will split. Application ionoselective membrane prevents ions migrate from the working solution colloid.

Application of electrophoresis.

Fig.10. The movement of molecules during the electrophoresis.

Electrophoresis is used to separate substances whose molecules have a total electric charge. In pharmaceutical research Electrophoretic separation used in the analysis of drugs containing amino acids, peptides, nucleic acids, unsaturated and saturated fatty acids, derivatives of carbohydrates, lipoproteins, hlyukoproteyidy and other macromolecular compounds.

Low voltage electrophoresis on paper and cellulose acetate is widely used in the analysis of amino acids, peptides and amines, especially at low concentrations of these substances in medicines. At high concentrations of substrates, more effective use of high-voltage electrophoresis. High rozdilnalna high-resolution thin-layer electrophoresis is used in pharmacy for the analysis of naphthols, phenols and inorganic ions.

Pulsed current and its characteristics

Electrical impulses called short-term change in amperage. Pulses, called repetitive pulsed current.

Fig.11. The change of current with time.

Typical plots of momentum are:

1-2 front, top 2-3, 3-4 cut (front or rear), tail 4-5.

Ratio  called the slope of the front.

Fig.12. The period of pulse current.

The period of pulse current  - is the average time between the start of adjacent pulses. The reciprocal of the pulse repetition frequency is called:

 (13) Ratio (14)

called duty cycle repetition. And the inverse  value

 (15)

fill factor.

Effects of pulsed current to the tissue.

Effects of pulsed current on the body is determined by the frequency and form.

At low frequencies (<500 kHz) electric current causes irritating effect on biological tissue. This will be determined by law DuBois-Reymond and Horveha-Weiss-Lanika.

1. Irritating effect stumu directly proportional rate of growth of current, ie the steepness of the front pulse.

2. In certain limits irritant effect is proportional to the pulse duration.

3. Physiological effects of pulsed current depends on the duty cycle (fill factor).

Specific physiological effect of pulse current, pulse or individual is determined by its shape.

Electrostimulation - electrotherapy method aimed at restoring impaired organ function by replacing the natural nerve impulse low-frequency pulse current. Restoration of disturbed rhythm - the main purpose of electrotherapy.

Use of pulse and AC therapy.

Pulse electrotherapy ( elektrosonterapiya , electrical , electroanalgesia , diadynamic ). Electrocoagulator , diatermokoahulyator .

Elektrosleep - Method neurotropic therapy, which is based on the impact on the patient's central nervous system constant pulse current (preferably rectangular ) low frequency ( 1-160 Hz) and low power (10 mA) with a short duration pulses ( 0.2-0.5 ms). Pulse current parameters for these effects on the orbital -occipital technique causes a condition close to physiological sleep ( electrosleep ). The action consists of electro reflex and immediate , direct impact on brain power . This current penetrates through the holes in the brain sockets , extends along the blood vessels and is sensitive nuclei of cranial nerves, pituitary, hypothalamus, reticular formation and other brain structures. Lead is a neuro- reflex mechanism of electro- stimulation associated with such an important reflex zones , the skin of the orbit, which is followed by reflex arc through a node Gasser transmitted to the thalamus and then to the cerebral cortex. The combination of reflex effects on receptor system with direct action on brain power provides suppression of the activating influence of the reticular formation of the midbrain neurons and blue spots on the cortex and activation of limbic structures , including the hippocampus . As a result, developing a special physiological condition of the body in which the infringement restore emotional, autonomic and humoral balance. This provides a positive effect electro diseases such as neurosis , hypertension , hypotension , peptic ulcer , asthma , hormonal dyzfunktsiyi . He has control , normalizing effect on the function of autonomic and somatic systems , regardless of whether these features were pathologically enhanced or weakened to treatment. This is reflected in the reduction of vascular tone , increased transport processes , increase oxygen capacity of the blood, stimulate hematopoiesis and immunological processes, normalize blood clotting , restoring homeostasis. Activated secretory function of the gastrointestinal tract , improves excretory activity and reproductive systems. Electro helps restore impaired carbohydrate, lipid , protein and mineral metabolism , activates hormone- productive function of endocrine glands. Under the influence of a rectangular pulse current in the brain are stimulated production of serotonin and endorphins , which may explain the decrease in conditioned reflex activity and emotional activity , sedative and analgesic effect of electro . Outspoken as the assumption that the mechanism of therapeutic action takes place electro ability of brain neurons metabolize certain rhythm pulse current , which makes a very attractive prospect bioupravlinnya electrical activity of the brain in the desired direction.

Fig.13. Implementation procedures electrosleep.

In the therapeutic action of electro distinguish two phases: inhibition and disinhibition. Phase inhibition clinically characterized drowsy state, sleepiness, often sleeping urezhennyam pulse and respiration, lower blood pressure and bioelectrical brain activity (according to EEG). Age of inhibition (or activation) appears shortly after the procedure and is expressed in the appearance of vigor, freshness, vigor, increase efficiency, improve mood. Thus, we should note two main areas of action electro: protivostressovoe, sedative (1st phase) and stimulating, increasing overall vitality (2nd phase electro). Electro, approaching in character to normal physiological sleep before it has a number of distinctive features: has antiseptic, anti-hypoxic effect, unlike sleep medication prevents complications and intoxications; has a regulating and normalizing influence almost every function of the body, restores the state homeostasis.

Elektrosleep used for portable, handheld devices for one patient: "Electro-4T", "Electro-5" (ES-10-5) and stationary device "Electro-3" to 4 simultaneous effects on patients. They are the generator voltage pulses of constant polarity and rectangular with a certain duration and variable frequency (up to 160 Hz). Devices attached to two pairs of special electrodes which are mounted on the patient in the form of masks.

Before the procedure, physician, physical therapist should hold a conversation with a patient about electrotherapy and warn him about those feelings he will experience . The procedure is performed in an environment that promotes the onset of sleep - in napivzatemneniy room , in a quiet, comfortable temperature and oxygen regime. The patient must undress and go to bed in a calm relaxed pose, and then the nurse establishes and imposes electrodes. Two of them, embedded in a rubber cuff with a metal cups filled with a cotton swab moistened with water or a solution of drug substance placed upon the closed eyelids and connected to the negative pole apparatus for electro . Two other electrode after filling them with wet cotton swab is placed upon the area of ​​the mastoid process of temporal bone and connecting the positive pole of the machine. Maybe changing polarity of electrodes. Then , finding an adequate frequency current, start slowly increase his strength to mild tingling sensation , painless vibration. Pulse frequency is selected based on the patient and the nature of the disease . Currently, the dominant approach is , where in the case of the predominance of organic degenerative processes in the vessels and the formation of the brain, with marked CNS excitement appointed electrosleep with pulse frequency of 5 to 20 Hz. In diseases which are based on functional disorders of CNS , there is a predominance of inhibitory processes or inhibition of sympathoadrenal activity ( neurosis , hypertension , etc.), use 60120 Hz pulse frequency . Perhaps more promising is the principle of individual selection frequency exposure from a study of frequency and power components of the EEG of the patient. Possible other approaches to individual selection frequencies for electro . Per course appropriately selected frequency usually does not change. Duration of treatment ranged from 30-40 to 60-90 minutes, depending on the characteristics of the nervous system of the patient and the nature of the pathological process. Procedures carried out daily or every other day , the course prescribed 10-15 influences.

Fig.14. Apparatus for the treatment of electrosleep-ES-10-5 "Electrosleep".

PURPOSE.

Apparatus for the treatment of electro-ES-10-5 "Electro" is used for therapeutic effects on the cerebral cortex of low frequency pulsed current rectangular shape. The device is used to treat diseases, the pathogenesis of which is the formation of stagnant pockets of excitation or inhibition in the cerebral hemispheres of the brain and disruption of normal relations cortico-subcortical regulation of somatic functions.

Apparatus for electrotherapy electro-ES-10-5 "Electro" is used:

- In Therapy (Pediatrics);

- The Skin Clinic;

- In gynecology;

- The treatment of neuropsychiatric diseases;

-         In surgical practice.

Apparatus for the treatment of electro-ES-10-5 "Electro" working principle is as follows:

Provides generate current pulses of low frequency rectangular in continuous mode. Fluctuations summarizes the electrodes masks that overlap the eye sockets and the occipital region of the head. The device has a high degree of protection against electric shock and requires no protective grounding.

Apparatus for electrotherapy electro-ES-10-5 "Electro" has the following specifications:

- AC - 220 V, 50 Hz;

- Frequency of repetition - 5, 10, 20, 40, 80, 100, 160 Hz;

- Power consumption from the mains - 25 VA;

- Relative error of frequency 2;

- Pulse - 0.5 ms;

- Dimensions - 108h300h315mm;

-         Weight - 3.5 kg.

The device "radius cranio-01" implemented basic types of transcranial electrotherapy(TET), which are widely used in medical practice, namely:

- Elektrosleep (Эson);

- Transcranial electro (TЭA);

- Transcranial electrostimulation (thermal power plants);

- Mezodientsefalna modulation (MDM);

- Transcranial galvanization and electrophoresis (GT);

- Transcranial interferential (Tinto);

- Therapeutic elektrooptymizatsiya (FEASIBILITY REPORT).

Through innovative methods of influence on the structure of the brain "radius cranio-01" can get positive results from treatment for most common ailments, as well as any illness or disease process in the body violate the functional state, adaptation and adaptive mechanisms kortikovistseralni relationships that can normalize methods TET. This body will cope with the problems that have arisen, "cranio" only "adjusts" to its proper operation. This is important because this method does not cause an imbalance in the body, as is the case with the classical treatment of drugs.

The mechanism of action of transcranial electrotherapy (TET) is reflexive and immediate impact rectangular pulse current structure of the human brain. Impact on the region of the head is patient plated, low-and midrange power a small pulse currents (up to 15mA). The greatest impact of pulse currents are subcortically-formation, located near the base of the brain lyumbichna system. As a result, significantly changing their functional status, improved vegetative provide different functions, central nervous system, cortical-subcortical relationships.

Treatment and rehabilitation of patients from a wide range of diseases:

- Stress, fatigue, sleep disturbance;

- To normalize mental and physical status;

- To speed up the healing process after injury;

- Alcohol, tobacco, drug and other addictions;

- Prevention of immunodeficiency;

- Normalization of the functional state of the central nervous system;

- Toxemia of pregnancy, preparation for childbirth;

- Allergic disease;

- Diseases of the nervous system;

- The consequences of closed craniocerebral injury;

- Hypertension stage I-II;

- For anesthesia;

- Gastric ulcer and 12 duodenal ulcer;

- Coronary heart disease.

Comfort and precision the impact of procedures provided by special nosological electrode stencils as original masks designed for different types kraniotserebralnoho impact.

Alternating current. Impedance alternating current at stake.

In the broadest sense alternating current - is any current that varies with time. We consider alternating current as forced electromagnetic vibrations.

Consider three different circles each of which applied voltage

 (16) а) б) в) Fig.17. Circle alternating current voltage is applied to them.

Amperage in a circle with a resistor will vary in phase with the applied voltage:

 (17)

Current strength in terms of the inductor will fall in phase from applied voltage to :

 , (18)

and the current in terms of the capacitor will outperform the phase voltage at :

 (19)

Using vector diagrams that can be represented as follows

 а) б) в) Fig.18. Vector diagrams areas of strength and tension.

For a circle with a resistor

 (20)

ohmic resistance for a circuit with inductors

 (21)

inductive reactance, and for the range of capacitor

 (22)

capacitive impedance.

Consider the circuit in which a resistor connected in series, the coil and capacitor

Fig.19. Terms which are connected in series resistor, coil and condenser.

In general, the current in the voltage range and did not change in one phase. Find  the method of vector diagrams. Print the voltage can be expressed as the sum of three vectors , ,  (Fig.20.).

Fig.20.Vektor diagram stresses.

The value of  can be found by the Pythagorean theorem:

 (23)

Or

 (24)

Where

 (25)

- Full range of alternating current impedance, which is called impedance.

Phase shift   between the voltage and amperage is determined from the triangle voltage:

Electrotherapy low frequency currents.

Apparatuses for low-frequency electrotherapy.

Portable single-channel device "radius, 01" for the treatment of various diseases using low frequency electrotherapy currents. Beneficial combines the functions for:

- Galvanization and drug electrophoresis (GT);

- Diadynamic therapy (OH DL, OM, CP, DP, RH, DV);

- Advanced amplipulse therapy (SMT1, SMT2, SMT3, SMT4, SMT5).

The device can be successfully used in medical and health resorts in the dental office or beauty salon, as well as for patients at home. Can be used in sports medicine and in private medical practice.

Indications:

- Diseases of the nervous system that occur with pain;

- Neurological manifestations of osteochondrosis;

- Joint disease;

- Diseases that require electrical stimulation of internal organs;

- Diseases of stomach and duodenum;

- Diseases of the biliary tract;

- Bowel Disease;

- Lung disease;

- Kidney disease;

- Phantom pain.

Fig.22. Device for electrotherapy currents of low frequency "Radius-01 FT»

Portable single-channel device "radius FT-01" is designed for the treatment of various diseases using low frequency electrotherapy currents. Beneficial combines the functions for: - Galvanization and drug electrophoresis (GT);

- Diadynamic therapy (OH DL, OM, CP, DP, RH, DV);

- Advanced amplipulse therapy (SMT1, SMT2, SMT3, SMT4, SMT5);

- Fluctuarization (FT);

- Electrical (ЭSM);

- Elektrosleep (Эson).

The device can be successfully used in medical and health resorts in the dental office or beauty salon, as well as for patients at home. Can be used in sports medicine and in private medical practice.

Indications:

- Diseases of the nervous system that occur with pain;

- Neurological manifestations of osteochondrosis;

- Joint disease;

- Diseases that require electrical stimulation of internal organs;

- Diseases of stomach and duodenum;

- Diseases of the biliary tract;

- Bowel Disease;

- Lung disease;

- Kidney disease;

- Phantom pain.

Interference - therapeutic application of low-frequency (1-100 Hz) "whipping", whose frequency may be constant throughout the procedure or be changed in the selected range. "Beating", which is a series of mid-oscillation current, formed inside the body tissues as a result of interference (addition) of two output currents of high frequency, which summarizes the surface of the body in two separate chains and differ in frequency.

Output currents that are midrange (3850-4000 Hz), passing through the epidermis without causing significant excitation of surface tissue and discomfort under the electrodes. At the same time, "beats" that are formed have a stimulating effect on motor nerves and muscle fibers that causes increased blood circulation, activate metabolism and reduce pain in the area of ​​influence. Interference currents that produce less intense stimulating effect than continuous currents are used for diseases of the peripheral nervous system, mainly in the subacute stage of the process.

Leading role in the mechanism of therapeutic action interferential improves peripheral circulation. It appears normalization of abnormal tone of arteries and capillary bed, an increasing number of active collaterals, improve microcirculation. In the mechanism of increased peripheral vascular fundamental importance interference suppression level currents sympathetic autonomic nervous system and increased allocation during the procedure vasoactive substances. In addition, the currents cause muscle contraction, providing a kind of massage effects, which result can be improved peripheral circulation and lymph flow.

Stimulation of blood flow leads to a local temperature increase, improve oxygen supply and removal of anoksemii, rapid removal of toxic metabolic products, activation of the reticuloendothelial system. When interferential tissue pH shifted to the alkaline side, which favorably affects the course of the inflammatory process. Interference current, according to some authors, has bactericidal or bacteriostatic properties. He also inherent trophic-regenerative effect.

Indications for use interferential: diseases of the nervous system (neuritis, neuralgia, neurological manifestations of osteochondrosis, causalgia, phantom pain, bedwetting, etc.), cardiovascular system (hypertension I and II,., Dystonia, atherosclerotic vascular occlusion limbs, varicose veins, thrombophlebitis effects, etc.), injuries of the musculoskeletal system, arthritis, arthrosis, joint contractures, osteochondropathy, diseases of the gastrointestinal tract with a predominance of motility, inflammatory disease of the uterus, and some skin diseases and others.

Technology and Methods Interference.

The patient is placed during the procedure while sitting or lying down, depending on the nature of disorder and localization effects. For the interferential using metal electrodes (two pairs) with thin hydrophilic spacers. In the most widely used method of stable influence electrodes installed so that the electrical current from them perehreschuvavsya in the area of ​​pathological center or interested bodies (tissues).

Amperage during interferential metered by its density at the electrodes and the feelings of the patient. The patient should feel a sense of deep, strong enough, but pleasant vibration at frequencies that vary rhythmically, or feel "crawling" - at a constant frequency. It should be remembered: the more intense painful events, the dosage should be less current. In the acute stage of the disease is usually current using less power, and in chronic cases - current greater strength. After getting used tissues to interference flow during the procedure must constantly increasing current strength with decreasing his feelings.

Amplipulse therapy - a method of electrotherapy in which the patient is influenced variable sinusoidal modulated currents low power. They combine the advantages of high currents and low frequencies.

For amplipulse therapy used variable frequency sinusoidal currents 2000-10000 Hz modulated sinusoidal oscillations of low frequency (in the range 10 - 150 Hz). In contrast to the low frequency currents, providing a pronounced stimulating effect on the neuromuscular and vascular systems, high frequency does not meet with great resistance from the skin, penetrates deep into the tissue does not cause significant irritation of the skin receptors. It is well tolerated, has a stimulating effect on the deep tissues. As a result of increased outflow of metabolic products of the pathological focus reduces swelling - one of the causes of pain. Stop the pain reduces spasm of blood vessels, they expand, improve nutrition of tissues.

Acting in sync with the normal oscillations bioenergy body that occur during the activity of the brain , nerves and muscles (10 to 150 Hz ) and increasing their effect sinusoidal modulated currents , we thus restoring normal function of tissues and organs. To reduce the effects of adaptation, expanding the range of tissues that are involved in the process of arousal, and increase the effectiveness of treatment resorted to alternating two different modulated frequencies. In this case one of them remains the same - 150 Hz , and the second adjustable between 10-150 Hz with separate control their duration within 1-5 seconds. Can also be modulated oscillations alternating with pauses and modulated and unmodulated fluctuations. Expressed analgesic effect , improving the functional state of the central and peripheral nervous system , improve peripheral circulation and in the absence of trophic tissue irritation under the electrodes determine the main indications for the use of sinusoidal modulated currents. They are prescribed for diseases involving violations of peripheral blood , the functional state of the neuromuscular system , trophic tissues, chronic inflammation (radiculitis different origins and trends , including those with severe neuro- vascular disorders , neuralgia , neuritis , plexites , the effects Depth - injury motor vehicle , violation of trophic tissues , including pressure ulcers in spinal cord lesions , subacute and chronic gynecological diseases ). The ability to provide current motor excitation allows them to apply for electrical striated muscles, including the stimulation of respiration, the gastrointestinal tract, ureter peristalsis and others. In the absence of irritation and discomfort , this method is widely used in children.

Indications for use amplipulse therapy : injuries and diseases of the peripheral nervous system and reflex tonic pain syndromes , diseases of the vegetative nervous system with neurotrophic and vascular disorders, diseases of the nervous system movement disorders as central, peripheral and mixed paresis and paralysis ; atherosclerotic vascular obliteration limbs , chronic lymphostasis , diseases of the digestive system (chronic gastritis with secretory insufficiency , peptic ulcer and duodenal ulcer in acute phase and partial remission, reflyuksezofahit , hypotonic and hypokinetic disorders of biliary tract and gall bladder with no stones , etc.); disruption of lipid metabolism exogenously - constitutional , diabetes, respiratory disease ( prolonged exacerbation of chronic pneumonia , chronic bronchitis and bronchiectasis beyond the acute stage, mild asthma and moderate levels ), rheumatoid arthritis, minimum and average degree of activity of the process , arthritis , periarthritis , chronic inflammatory diseases of the female genitalia , male impotence functional nature , chronic prostatitis, tsistalgii , bedwetting in children , urolithiasis (for ureteral stones exile ), inflammatory and degenerative diseases of the anterior and posterior parts of the eye. Given the ability of sinusoidal modulated currents penetrate deeply into the tissues , without causing discomfort and burns prefer amplipulse therapy (before diadynamic ) in pediatric patients , the effects on the mucous membranes .

Fluctuarization - use for therapeutic purposes AC, partially or fully rectified current low voltage (100 V) with frequency (up to 2000 Hz) and amplitude (up to 3 mA/sm2) that vary randomly. The least stimulating effect is symmetrical current fluctuations as changes in the concentration of ions in semi-permeable membranes to some extent smoothed the same ion concentration changes that occur in the opposite direction when the direction of current. Aperiodychnist change appearance of peaks increases the irritant violations and reduces tissue adaptation compared with the effect of periodic oscillations of the same amplitude current. A strong effect is partially straightened fluctuations and even more powerful - fully extended. The above form of the current features of their exciting action, like diadynamical current, activating blood circulation and trophic processes in the field of current flow, providing an analgesic effect. Flyuktuorizatsiya mainly used in dental practice and with somatic diseases.

The peculiarity of flyukturuyuchyh currents on the body is that through random changes of parameters during the exposure time in the tissues do not develop the phenomenon of adaptation. Flyukturuyuchi currents intensely irritating propryo and interoreceptors, accompanied by a simultaneous reduction in myofibrils painless. It is noted a slight increase in temperature of tissues, there is congestion, which in turn activates trophic tissues, phagocytosis, enzyme activities and processes of dispersal of toxic substances from inflammation, enhances cell immunogenesis. When exposed to purulent inflammatory foci Fluctuarization is limiting the spread of the process and its reverse development. Postoperative use of currents facilitates the rapid rejection of necrotic tissue, cleaning wounds, accelerated regeneration. Most occur the formation of granulation tissue and epithelization of the wound. So flyukturuyuchi currents can be used as a means of treating acute, including pus, inflammation.

Indications for use Fluctuarization. Fluctuarization mainly used in dentistry to relieve pain due to exacerbation of chronic periodontitis, alveolitis, pulpit, Arthritis TMJ, glossalgia, and acute exacerbations of chronic inflammation, including purulent (abscess, abscess, periodontitis, etc.), actinomycosis. In addition, these currents can be used to treat pain syndromes caused by lesions of peripheral nervous system (neuritis, neuralgia, radiculitis, hanhlionity, etc.) as well as in treatment of some gynecological diseases inflammatory origin.

Electrotherapy high frequency.

The concept darsonvalization. The physical principle of the apparatus darsonvalization. Methods of. Indications and contraindications.

Darsonvalization - use for therapeutic purposes high frequency current (IN kHz) and voltage (20-30 kV) at low power (up to 5 mA) current modulated by a series of oscillations lasting 100 ms following a frequency of 100 Hz. The method derives its name from the author - French physicist, physiologist and physician Jacques D'Arsonval.

Physical characteristics.

Operating factor - pulsed, bystrozatuhayuschiy, corona discharge (spark) High Frequency (1yu kHz), high voltage (20-30 kV) and low power CO 015 mA). Series of pulse duration 100 ms, frequency 50 Hz.

APPARATUS "Iskra-1", "Iskra-2" device for portable darsonvalization "Crown M" and "Pulse 1". Electrodes are figured vacuum glass bottles of various shapes. Electrodes are porous and external. Porous electrodes: ear, vaginal, nasal, rectal large and small mouth. External electrodes: Grebeshkova, large and small mushroom. External electrodes treated with alcohol before the procedure, cavity - a disinfectant solution, then with water and alcohol.

Preparation of the apparatus "Iskra-1". The device is grounded, including the network and insert the electrode into the holder. The switch network is transferred to the "1" position, the pilot light lit. Then switch is transferred to the "2", "3" and so on, until the needle gauge is established within the color scale sector. The device is heated for 3 minutes, the electrode lead-up to the pathological focus and handle "power" increase the output voltage until the quiet or spark. Position the handle on the number "3" corresponds to small, the "5" - the average, the "8" high intensity discharge.

Fig.23. Implementation procedures darsonvalization.

Methods and techniques of the procedure.

There are general and local darsonvalization. Total darsonvalization (apparatus "Whirlwind 1") due to significant interference is not currently used. The local darsonvalization carried out on pathological focus on the segmental reflex zone. Methods are also divided into superficial and bladder. Surface are stable and labile, and eflyuvialnymi contact with air gap of 2-4 mm. Areas of the body subject to exposure prypudryuyut talc (except scalp and face), abdominal electrodes smeared with sterile vaseline and fixed in the cavity.

INDICATIONS.

Darsonvalization shown in the following main syndromes: common inflammatory changes, pain, presence of fluid in the cavity (perifocal improve blood flow), respiratory, vascular, cardiac, hepatic, renal insufficiency, and 1 c., Hypertensive, Raynaud's, joint dysfunction, spinal deformity; cutaneous, impaired tissue integrity, allergic; syndrome overgrowth of connective tissue (hyperplastic), menopause, tsefalhicheskom, encephalopathy, entsefa-lomielopatii, hypothalamic, polyneuropathy, neuropathy, dis-circulatory encephalopathy, vestibular, liquor hyperten-Zia, diskineticheskih (spastic and atonycheskom) , edema, tsereb-roishemicheskom, atrophic, asthenic, vegetative-vascular dis-Tony, radicular, radicular-vascular; reflex.

Diseases: wound healing (sores, wounds, skin damage), skin diseases (eczema, neurodermatitis, herpes), allo security of, itchy dermatitis, vascular pathology (endarteritis in the initial stage, varicose veins of the lower extremities, migraine, atherosclerosis of vessels of brain, Raynaud's disease, hemorrhoids, vasomotor rhinitis), sleep disorder, climacteric neurosis, enuresis, neurocirculatory dystonia (on collar area), neuritis and myositis, periodontal disease, cracks anus and vagina, cervical erosion, pharyngitis, glossitis, stomatitis; trauma pathology (removal of numbness and paresthesias), osteochondrosis, hearing loss, impotence.

CONTRAINDICATIONS.

In general, the syndrome: cardiac arrhythmias, myshechnotonicheskom, hypotensive, neurotic.

Disease: hysteria, active pulmonary tuberculosis, post heart attack (within 6 months), coronary heart disease, angina W-SU FC, ​​acute stroke, hypotension, idiosyncrasy current abdominal pain when administered electrodes.

Apparatus for local darsonvalization Crown:

Fig.24. Apparatus for local darsonvalization Crown (3 electrodes).

Apparatus darsonvalization crown replaces , complements and reinforces creams and ointments has unique opportunities for prevention and treatment of dermatological , neurological , respiratory and other diseases.

Apparatus for local darsonvalization Crown is used in cosmetics , sports medicine, health care facilities and at home.

Corona discharge that occurs between the body surface and electrode , developing not only in the air gap , but deep in biological tissues. Electromagnetic fluctuations in different range stimulate metabolism, tissue respiration, normalized activity of the autonomic nervous system, the endocrine glands , promote partial resorption of salt deposits , regeneration of damaged tissues.

Apparatus Crown meets state standards for medical devices .

Apparatus darsonvalization Crown recommended for treatment of:

- Skin diseases (eczema, herpes, acne , atopic dermatitis , psoriasis, lichen planus , scleroderma , hair loss , seborrhea );

- Purulent and inflammatory processes ( boils , burns , frostbite , bruises , hematoma , postoperative infiltrates and wounds , sores , etc.);

- Diseases of the respiratory system (tracheitis , bronchitis , asthma );

- Diseases of the nose (allergic rhinitis, sinusitis, etc. );

- Diseases of the muscles , tendons and articular bags aponeurosis ( myalgia, myositis );

- Diseases of the joints ( arthritis , arthritis, spondylarthritis , etc.);

- Diseases of arteries and veins ( endarteritis obliterans , Raynaud's disease , varicose veins , thrombophlebitis , etc.);

- Neurological diseases ( neuritis , functional vascular disease).

Oddsei - What are the odds of anything.