The use of ultraviolet rays in medicine. What is ultraviolet radiation - properties, application, ultraviolet protection

The spectrum of rays visible to the human eye does not have a sharp, clearly defined boundary. Some researchers call the upper limit of the visible spectrum 400 nm, others 380, and still others shift it to 350...320 nm. This is explained by different light sensitivity of vision and indicates the presence of rays invisible to the eye.
In 1801, I. Ritter (Germany) and W. Walaston (England), using a photographic plate, proved the presence of ultraviolet rays. Beyond the violet end of the spectrum, it turns black faster than under the influence of visible rays. Since the blackening of the plate occurs as a result of a photochemical reaction, scientists have concluded that ultraviolet rays are very active.
Ultraviolet rays cover a wide range of radiation: 400...20 nm. The radiation region of 180... 127 nm is called vacuum. Using artificial sources (mercury-quartz, hydrogen and arc lamps), producing both line and continuous spectrum, ultraviolet rays with a wavelength of up to 180 nm are obtained. In 1914, Lyman explored the range up to 50 nm.
Researchers have discovered the fact that the spectrum of ultraviolet rays from the sun reaching earth's surface, very narrow - 400...290 nm. Doesn't the sun emit light with a wavelength shorter than 290 nm?
The answer to this question was found by A. Cornu (France). He found that ozone absorbs ultraviolet rays shorter than 295 nm, after which he put forward a hypothesis: the Sun emits short-wave ultraviolet radiation, under its influence oxygen molecules break down into individual atoms, forming ozone molecules, therefore, in the upper layers of the atmosphere, ozone should cover the earth with a protective screen. Cornu's hypothesis was confirmed when people rose to the upper atmosphere. Thus, under terrestrial conditions, the spectrum of the sun is limited by the transmission of the ozone layer.
The amount of ultraviolet rays reaching the earth's surface depends on the height of the Sun above the horizon. During the period of normal illumination, the illumination changes by 20%, while the amount of ultraviolet rays reaching the earth's surface decreases by 20 times.
Special experiments have established that when rising upward for every 100 m, the intensity of ultraviolet radiation increases by 3...4%. The share of scattered ultraviolet radiation at summer noon accounts for 45...70% of the radiation, and that reaching the earth's surface - 30...55%. On cloudy days, when the solar disk is covered with clouds, mainly scattered radiation reaches the Earth's surface. Therefore, you can tan well not only in direct sunlight, but also in the shade and on cloudy days.
When the Sun is at its zenith, equatorial region Rays with a length of 290...289 nm reach the earth's surface. In mid-latitudes there is a short-wave boundary, in summer months, is approximately 297 nm. During the period of effective illumination, the upper limit of the spectrum is about 300 nm. Beyond the Arctic Circle, rays with a wavelength of 350...380 nm reach the earth's surface.

The influence of ultraviolet radiation on the biosphere

Above the range of vacuum radiation, ultraviolet rays are easily absorbed by water, air, glass, quartz and do not reach the Earth's biosphere. In the range of 400... 180 nm, the effect on living organisms of rays of different wavelengths is not the same. The most energy-rich short-wave rays played a significant role in the formation of the first complex organic compounds on Earth. However, these rays contribute not only to the formation, but also to the decay organic matter. Therefore, the progress of life forms on Earth occurred only after, thanks to the activity of green plants, the atmosphere was enriched with oxygen and, under the influence of ultraviolet rays, a protective ozone layer was formed.
Of interest to us are ultraviolet radiation from the Sun and artificial sources of ultraviolet radiation in the range of 400...180 nm. Within this range there are three areas:

A - 400...320 nm;
B - 320...275 nm;
C - 275...180 nm.

There are significant differences in the effect of each of these ranges on a living organism. Ultraviolet rays act on matter, including living matter, according to the same laws as visible light. Part of the absorbed energy is converted into heat, but the thermal effect of ultraviolet rays does not have a noticeable effect on the body. Another way of transmitting energy is luminescence.
Photochemical reactions under the influence of ultraviolet rays are most intense. The energy of ultraviolet light photons is very high, so when they are absorbed, the molecule ionizes and breaks into pieces. Sometimes a photon knocks an electron out of the atom. Most often, excitation of atoms and molecules occurs. When absorbing one quantum of light with a wavelength of 254 nm, the energy of the molecule increases to a level corresponding to the energy of thermal motion at a temperature of 38000°C.
The bulk of solar energy reaches the earth in the form of visible light and infrared radiation, and only a small part in the form of ultraviolet radiation. The UV flux reaches its maximum values ​​in midsummer in the Southern Hemisphere (the Earth is 5% closer to the Sun) and 50% of the daily amount of UV arrives within 4 midday hours. Diffey found that for latitudes with temperatures of 20-60°, a person sunbathing from 10:30 to 11:30 and then from 16:30 to sunset will receive only 19% of the daily UV dose. At noon, the UV intensity (300 nm) is 10 times higher than three hours earlier or later: an untanned person needs 25 minutes to get a light tan at noon, but to achieve the same effect after 15:00, he will need to lie in the sun not less than 2 hours.
The ultraviolet spectrum, in turn, is divided into ultraviolet-A (UV-A) with a wavelength of 315-400 nm, ultraviolet-B (UV-B) -280-315 nm and ultraviolet-C (UV-C) - 100-280 nm which differ in penetrating ability and biological effects on the body.
UV-A is not retained by the ozone layer and passes through glass and the stratum corneum of the skin. The UV-A flux (mean value at noon) is twice as high at the Arctic Circle as at the equator, so its absolute value is greater at high latitudes. There are no significant fluctuations in UV-A intensity at different times of the year. Due to absorption, reflection and dispersion when passing through the epidermis, only 20-30% of UV-A penetrates into the dermis and about 1% of its total energy reaches the subcutaneous tissue.
Most UV-B is absorbed by the ozone layer, which is "transparent" to UV-A. So the share of UV-B in all ultraviolet radiation energy on a summer afternoon is only about 3%. It practically does not penetrate through glass, 70% is reflected by the stratum corneum, and is weakened by 20% when passing through the epidermis - less than 10% penetrates into the dermis.
However long time It was believed that the share of UV-B in the damaging effects of ultraviolet radiation is 80%, since it is this spectrum that is responsible for the occurrence of sunburn erythema.
It is also necessary to take into account the fact that UV-B is scattered more strongly (shorter wavelength) than UV-A when passing through the atmosphere, which leads to a change in the ratio between these fractions with increasing geographic latitude (in northern countries) and time of day.
UV-C (200-280 nm) is absorbed by the ozone layer. If an artificial ultraviolet source is used, it is retained by the epidermis and does not penetrate the dermis.

The effect of ultraviolet radiation on the cell

In the effect of short-wave radiation on a living organism, the greatest interest is the effect of ultraviolet rays on biopolymers - proteins and nucleic acids. Biopolymer molecules contain ring groups of molecules containing carbon and nitrogen, which intensively absorb radiation with a wavelength of 260...280 nm. Absorbed energy can migrate along a chain of atoms within a molecule without significant loss until it reaches weak bonds between atoms and breaks the bond. During this process, called photolysis, fragments of molecules are formed that have a strong effect on the body. For example, histamine is formed from the amino acid histidine, a substance that dilates blood capillaries and increases their permeability. In addition to photolysis, denaturation occurs in biopolymers under the influence of ultraviolet rays. When irradiated with light of a certain wavelength, the electrical charge of molecules decreases, they stick together and lose their activity - enzymatic, hormonal, antigenic, etc.
The processes of photolysis and denaturation of proteins occur in parallel and independently of each other. They are caused by different radiation ranges: rays of 280...302 nm cause mainly photolysis, and 250...265 nm - mainly denaturation. The combination of these processes determines the pattern of action of ultraviolet rays on the cell.
The most sensitive cell function to ultraviolet rays is division. Irradiation at a dose of 10(-19) J/m2 causes the division of about 90% of bacterial cells to stop. But the growth and vital activity of cells does not stop. Over time, their division is restored. To cause the death of 90% of cells, suppression of the synthesis of nucleic acids and proteins, and the formation of mutations, it is necessary to increase the radiation dose to 10 (-18) J/m2. Ultraviolet rays cause changes in nucleic acids that affect the growth, division, and heredity of cells, i.e. on the main manifestations of life.
The importance of the mechanism of action on nucleic acid is explained by the fact that each DNA (deoxyribonucleic acid) molecule is unique. DNA is the cell's hereditary memory. Its structure encrypts information about the structure and properties of all cellular proteins. If any protein is present in a living cell in the form of tens or hundreds of identical molecules, then DNA stores information about the structure of the cell as a whole, about the nature and direction of metabolic processes in it. Therefore, disturbances in the DNA structure may be irreparable or lead to serious disruption of life.

The effect of ultraviolet radiation on the skin

Exposure to ultraviolet radiation on the skin significantly affects our body's metabolism. It is well known that it is UV rays that initiate the process of formation of ergocalciferol (vitamin D), which is necessary for the absorption of calcium in the intestine and ensuring the normal development of the bone skeleton. In addition, ultraviolet light actively affects the synthesis of melatonin and serotonin - hormones responsible for the circadian (daily) biological rhythm. Research by German scientists has shown that when blood serum is irradiated with UV rays, the content of serotonin, the “hormone of vigor”, which is involved in the regulation of the emotional state, increases by 7%. Its deficiency can lead to depression, mood swings, and seasonal functional disorders. At the same time, the amount of melatonin, which has an inhibitory effect on the endocrine and central nervous systems, decreased by 28%. It is this double effect that explains the invigorating effect spring sun, uplifting mood and vitality.
The effect of radiation on the epidermis - the outer surface layer of the skin of vertebrates and humans, consisting of human stratified squamous epithelium - is an inflammatory reaction called erythema. The first scientific description of erythema was given in 1889 by A.N. Maklanov (Russia), who also studied the effect of ultraviolet rays on the eye (photoophthalmia) and found that they are based on common causes.
There are caloric and ultraviolet erythema. Caloric erythema is caused by the effect of visible and infrared rays on the skin and the flow of blood to it. It disappears almost immediately after the cessation of irradiation.
After cessation of exposure to UV irradiation, after 2..8 hours, redness of the skin (ultraviolet erythema) appears simultaneously with a burning sensation. Erythema appears after a latent period, within the irradiated area of ​​the skin, and is replaced by tanning and peeling. The duration of erythema ranges from 10...12 hours to 3...4 days. The reddened skin is hot to the touch, slightly painful and appears swollen and slightly swollen.
Essentially, erythema is an inflammatory reaction, a burn of the skin. This is a special, aseptic (Aseptic - putrefactive) inflammation. If the radiation dose is too high or the skin is especially sensitive to them, the edematous fluid accumulates, peels off the outer layer of the skin in places, and forms blisters. In severe cases, areas of necrosis (death) of the epidermis appear. A few days after the erythema disappears, the skin darkens and begins to peel. As peeling occurs, some of the cells containing melanin are exfoliated (Melanin is the main pigment of the human body; it gives color to the skin, hair, and iris of the eye. It is also contained in the pigment layer of the retina and is involved in the perception of light), the tan fades. The thickness of human skin varies depending on gender, age (in children and the elderly - thinner) and location - on average 1..2 mm. Its purpose is to protect the body from damage, temperature fluctuations, and pressure.
The main layer of the epidermis is adjacent to the skin itself (dermis), which contains blood vessels and nerves. In the main layer there is a continuous process of cell division; older ones are forced out by young cells and die. Layers of dead and dying cells form the outer stratum corneum of the epidermis with a thickness of 0.07...2.5 mm (On the palms and soles, mainly due to the stratum corneum, the epidermis is thicker than on other parts of the body), which is continuously exfoliated from the outside and restored from the inside.
If the rays falling on the skin are absorbed by dead cells of the stratum corneum, they have no effect on the body. The effect of irradiation depends on the penetrating ability of the rays and the thickness of the stratum corneum. The shorter the radiation wavelength, the lower their penetrating ability. Rays shorter than 310 nm do not penetrate deeper than the epidermis. Rays with longer the waves reach the papillary dermis, which contains blood vessels. Thus, the interaction of ultraviolet rays with the substance occurs exclusively in the skin, mainly in the epidermis.
The main amount of ultraviolet rays is absorbed in the germinal (basic) layer of the epidermis. The processes of photolysis and denaturation lead to the death of styloid cells of the germ layer. Active protein photolysis products cause vasodilation, skin swelling, release of leukocytes and other typical signs of erythema.
Photolysis products, spreading through the bloodstream, also irritate the nerve endings of the skin and, through the central nervous system, reflexively affect all organs. It has been established that in the nerve extending from the irradiated area of ​​the skin, the frequency of electrical impulses increases.
Erythema is considered as a complex reflex, the occurrence of which involves active products of photolysis. The severity of erythema and the possibility of its formation depend on the state of the nervous system. On affected areas of the skin, with frostbite, or inflammation of the nerves, erythema either does not appear at all or is very weakly expressed, despite the action of ultraviolet rays. The formation of erythema is inhibited by sleep, alcohol, physical and mental fatigue.
N. Finsen (Denmark) first used ultraviolet radiation to treat a number of diseases in 1899. Currently, the manifestations of the effects of different areas of ultraviolet radiation on the body have been studied in detail. Of the ultraviolet rays contained in sunlight, erythema is caused by rays with a wavelength of 297 nm. To rays with longer or shorter wavelengths, the erythemal sensitivity of the skin decreases.
With the help of artificial radiation sources, erythema was caused by rays in the range of 250...255 nm. Rays with a wavelength of 255 nm are produced by the resonant emission line of mercury vapor used in mercury-quartz lamps.
Thus, the curve of erythemal sensitivity of the skin has two maxima. The depression between the two maxima is provided by the shielding effect of the stratum corneum of the skin.

Protective functions of the body

Under natural conditions, after erythema, skin pigmentation develops - tanning. The spectral maximum of pigmentation (340 nm) does not coincide with any of the peaks of erythemal sensitivity. Therefore, by selecting a radiation source, you can cause pigmentation without erythema and vice versa.
Erythema and pigmentation are not stages of the same process, although they follow one another. This is a manifestation of different processes related to each other. The skin pigment melanin is formed in the cells of the lowest layer of the epidermis - melanoblasts. The starting material for the formation of melanin are amino acids and adrenaline breakdown products.
Melanin is not just a pigment or a passive protective screen that fences off living tissue. Melanin molecules are huge molecules with a network structure. In the links of these molecules, fragments of molecules destroyed by ultraviolet radiation are bound and neutralized, preventing them from entering the blood and the internal environment of the body.
The function of tanning is to protect the cells of the dermis, the vessels and nerves located in it from long-wave ultraviolet, visible and infrared rays, which cause overheating and heat stroke. Near-infrared rays and visible light, especially its long-wave, “red” part, can penetrate tissue much deeper than ultraviolet rays - to a depth of 3...4 mm. Melanin granules - a dark brown, almost black pigment - absorb radiation in a wide range of the spectrum, protecting delicate internal organs, accustomed to a constant temperature, from overheating.
The body's operational mechanism to protect itself from overheating is a rush of blood to the skin and dilation of blood vessels. This leads to an increase in heat transfer through radiation and convection (The total surface of the skin of an adult is 1.6 m2). If the air and surrounding objects are at a high temperature, another cooling mechanism comes into play - evaporation due to sweating. These thermoregulatory mechanisms are designed to protect against exposure to visible and infrared rays from the Sun.
Sweating, along with the function of thermoregulation, prevents the effects of ultraviolet radiation on humans. Sweat contains urocanic acid, which absorbs short-wave radiation due to the presence of a benzene ring in its molecules.

Light starvation (deficiency of natural UV radiation)

Ultraviolet radiation supplies energy for photochemical reactions in the body. IN normal conditions sunlight causes formation small amount active photolysis products that have a beneficial effect on the body. Ultraviolet rays in doses that cause the formation of erythema enhance the functioning of the hematopoietic organs and the reticuloendothelial system ( Physiological system connective tissue, producing antibodies that destroy bodies and microbes foreign to the body), barrier properties of the skin, eliminate allergies.
Under the influence of ultraviolet radiation in human skin, fat-soluble vitamin D is formed from steroid substances. Unlike other vitamins, it can enter the body not only with food, but also be formed in it from provitamins. Under the influence of ultraviolet rays with a wavelength of 280...313 nm, provitamins contained in the skin lubricant secreted by the sebaceous glands are converted into vitamin D and absorbed into the body.
The physiological role of vitamin D is that it promotes the absorption of calcium. Calcium is part of bones, participates in blood clotting, compacts cell and tissue membranes, and regulates enzyme activity. A disease that occurs due to a lack of vitamin D in children in the first years of life, whom caring parents hide from the Sun, is called rickets.
In addition to natural sources of vitamin D, artificial ones are also used, irradiating provitamins with ultraviolet rays. When using artificial sources of ultraviolet radiation, it should be remembered that rays shorter than 270 nm destroy vitamin D. Therefore, using filters in the light flux of ultraviolet lamps, the short-wave part of the spectrum is suppressed. Solar starvation manifests itself in irritability, insomnia, and rapid fatigue of a person. In large cities, where the air is polluted with dust, ultraviolet rays that cause erythema almost do not reach the surface of the Earth. Long-term work in mines, engine rooms and closed factory workshops, work at night, and sleep during the daytime lead to light starvation. Light starvation is facilitated by window glass, which absorbs 90...95% of ultraviolet rays and does not transmit rays in the range of 310...340 nm. The color of the walls is also significant. For example, yellow color completely absorbs ultraviolet rays. Lack of light, especially ultraviolet radiation, is felt by people, pets, birds and indoor plants in the autumn, winter and spring periods.
Lamps that, along with visible light, emit ultraviolet rays in the wavelength range 300...340 nm can compensate for the lack of ultraviolet rays. It should be borne in mind that errors in prescribing the radiation dose, inattention to such issues as the spectral composition of ultraviolet lamps, the direction of radiation and the height of the lamps, the duration of lamp burning, can cause harm instead of benefit.

Bactericidal effect of ultraviolet radiation

It is impossible not to note the bactericidal function of UV rays. In medical institutions, this property is actively used to prevent nosocomial infections and ensure the sterility of surgical units and dressing rooms. The effect of ultraviolet radiation on bacterial cells, namely DNA molecules, and the development of further chemical reactions in them leads to the death of microorganisms.
Air pollution with dust, gases, and water vapor has a harmful effect on the body. The ultraviolet rays of the Sun enhance the process of natural self-purification of the atmosphere from pollution, promoting the rapid oxidation of dust, smoke particles and soot, destroying microorganisms on dust particles. The natural ability to self-purify has limits and, with very strong air pollution, is insufficient.
Ultraviolet radiation with a wavelength of 253...267 nm most effectively destroys microorganisms. If we take the maximum effect as 100%, then the activity of rays with a wavelength of 290 nm will be 30%, 300 nm - 6%, and rays lying on the border of visible light 400 nm - 0.01% of the maximum.
Microorganisms have varying sensitivity to ultraviolet rays. Yeasts, molds and bacterial spores are much more resistant to their action than vegetative forms of bacteria. Spores of individual fungi, surrounded by a thick and dense shell, thrive in high layers of the atmosphere and it is possible that they can travel even in space.
The sensitivity of microorganisms to ultraviolet rays is especially great during the period of division and immediately before it. The curves of the bactericidal effect, inhibition and cell growth practically coincide with the absorption curve of nucleic acids. Consequently, denaturation and photolysis of nucleic acids leads to the cessation of division and growth of microorganism cells, and in large doses to their death.
The bactericidal properties of ultraviolet rays are used to disinfect air, tools, and utensils; with their help, they increase the shelf life of food products, disinfect drinking water, and inactivate viruses when preparing vaccines.

Negative effects of ultraviolet radiation

A number of negative effects that occur when exposed to UV radiation on the human body are also well known, which can lead to a number of serious structural and functional damage to the skin. As is known, these damages can be divided into:

acute, caused by a large dose of radiation received in a short time (for example, sunburn or acute photodermatoses). They occur primarily due to UV-B rays, the energy of which is many times greater than the energy of UVA rays. Solar radiation is distributed unevenly: 70% of the dose of UV-B rays received by humans occurs in the summer and midday, when the rays fall almost vertically, and do not slide tangentially - under these conditions they are absorbed maximum amount radiation. Such damage is caused by the direct effect of UV radiation on chromophores - it is these molecules that selectively absorb UV rays.

delayed, caused by long-term irradiation with moderate (suberythemal) doses (for example, such damage includes photoaging, skin neoplasms, some photodermatitis). They arise mainly due to spectrum A rays, which carry less energy, but are able to penetrate deeper into the skin, and their intensity varies little during the day and practically does not depend on the time of year. As a rule, this type of damage is the result of exposure to the products of free radical reactions (remember that free radicals- these are highly reactive molecules that actively interact with proteins, lipids and genetic material cells).
The role of UV rays of the A spectrum in the etiology of photoaging has been proven by the work of many foreign and Russian scientists, but nevertheless, the mechanisms of photoaging continue to be studied using modern scientific and technical base, cell engineering, biochemistry and methods of cellular functional diagnostics.
The mucous membrane of the eye - the conjunctiva - does not have a protective stratum corneum, so it is more sensitive to UV radiation than the skin. Pain in the eye, redness, lacrimation, and partial blindness occur as a result of degeneration and death of cells of the conjunctiva and cornea. The cells become opaque. Long-wave ultraviolet rays, reaching the lens in large doses, can cause clouding - cataracts.

Artificial sources of UV radiation in medicine

Germicidal lamps
Discharge lamps are used as sources of UV radiation, in which, during the process of electrical discharge, radiation is generated containing a wavelength range of 205-315 nm (the rest of the radiation spectrum plays a secondary role). Such lamps include low- and high-pressure mercury lamps, as well as xenon flash lamps.
Low-pressure mercury lamps are structurally and electrically no different from conventional fluorescent lighting lamps, except that their bulb is made of special quartz or uviol glass with a high transmittance of UV radiation, on the inner surface of which there is no phosphor layer applied. . These lamps are available in a wide range of wattages from 8 to 60 W. The main advantage of low-pressure mercury lamps is that more than 60% of the radiation falls on the line with a wavelength of 254 nm, which lies in the spectral region of maximum bactericidal action. They have a long service life of 5,000-10,000 hours and instantaneous ability to work after they are ignited.
The bulb of high-pressure mercury-quartz lamps is made of quartz glass. The advantage of these lamps is that, despite their small dimensions, they have a large unit power from 100 to 1,000 W, which makes it possible to reduce the number of lamps in the room, but they have low bactericidal efficiency and a short service life of 500-1,000 hours. In addition, normal combustion mode occurs 5-10 minutes after they are ignited.
A significant disadvantage of continuous radiant lamps is the risk of contamination of the environment with mercury vapor if the lamp is destroyed. If the integrity of bactericidal lamps is damaged and mercury enters the room, thorough demercurization of the contaminated room must be carried out.
In recent years, a new generation of emitters has appeared - short-pulse ones, which have much greater biocidal activity. The principle of their operation is based on high-intensity pulsed irradiation of air and surfaces with continuous-spectrum UV radiation. Pulsed radiation is produced using xenon lamps, as well as lasers. There is currently no data on the difference between the biocidal effect of pulsed UV radiation and that of traditional UV radiation.
The advantage of xenon flash lamps is due to their higher bactericidal activity and shorter exposure time. Another advantage of xenon lamps is that if they are accidentally destroyed, the environment is not polluted with mercury vapor. The main disadvantages of these lamps, which hinder their widespread use, are the need to use high-voltage, complex and expensive equipment for their operation, as well as the limited life of the emitter (on average 1-1.5 years).
Germicidal lamps are divided into ozone and non-ozone.
Ozone lamps have a spectral line with a wavelength of 185 nm in their emission spectrum, which, as a result of interaction with oxygen molecules, forms ozone in air environment. High concentrations of ozone can have adverse effects on human health. The use of these lamps requires monitoring of the ozone content in the air and careful ventilation of the room.
To eliminate the possibility of ozone generation, so-called bactericidal “ozone-free” lamps have been developed. For such lamps, due to the manufacture of the bulb from a special material (coated quartz glass) or its design, the output of the 185 nm line radiation is eliminated.
Germicidal lamps that have expired or are out of order must be stored packaged in a separate room and require special disposal in accordance with the requirements of the relevant regulatory documents.

Bactericidal irradiators.
A bactericidal irradiator is an electrical device that contains: a bactericidal lamp, a reflector and other auxiliary elements, as well as devices for its fastening. Germicidal irradiators redistribute the radiation flux into the surrounding space in a given direction and are divided into two groups - open and closed.
Open irradiators use a direct germicidal flow from lamps and a reflector (or without it), which covers a wide area of ​​\u200b\u200bthe space around them. Installed on the ceiling or wall. Irradiators installed in doorways are called barrier irradiators or ultraviolet curtains, in which the bactericidal flow is limited to a small solid angle.
A special place is occupied by open combined irradiators. In these irradiators, due to the rotating screen, the bactericidal flow from the lamps can be directed to the upper or lower zone of the space. However, the efficiency of such devices is much lower due to changes in wavelength upon reflection and some other factors. When using combined irradiators, the bactericidal flow from shielded lamps must be directed to the upper zone of the room in such a way as to prevent direct flow from the lamp or reflector from escaping into the lower zone. In this case, the irradiance from reflected fluxes from the ceiling and walls on a conventional surface at a height of 1.5 m from the floor should not exceed 0.001 W/m2.
In closed irradiators (recirculators), the bactericidal flow from the lamps is distributed in a limited, small enclosed space and has no outlet to the outside, while the air is disinfected in the process of pumping it through the ventilation holes of the recirculator. When using supply and exhaust ventilation, bactericidal lamps are placed in the exit chamber. The air flow speed is provided either by natural convection or forced by a fan. Irradiators closed type(recirculators) should be placed indoors on the walls along the main air flows (in particular, near heating devices) at a height of at least 2 m from the floor.
According to the list of typical premises divided into categories (GOST), it is recommended that rooms of categories I and II be equipped with both closed irradiators (or supply and exhaust ventilation) and open or combined ones - when they are turned on in the absence of people.
In rooms for children and pulmonary patients, it is recommended to use irradiators with ozone-free lamps. Artificial ultraviolet irradiation, even indirect, is contraindicated for children with an active form of tuberculosis, nephroso-nephritis, a febrile state and severe exhaustion.
The use of ultraviolet bactericidal installations requires strict implementation of safety measures that exclude possible harmful effects on humans of ultraviolet bactericidal radiation, ozone and mercury vapor.

Basic safety precautions and contraindications for the use of therapeutic UV irradiation.

Before using UV irradiation from artificial sources, it is necessary to visit a doctor in order to select and establish the minimum erythemal dose (MED), which is a purely individual parameter for each person.
Since individual sensitivity varies widely, it is recommended that the duration of the first session be reduced to half the recommended time in order to establish the user's skin reaction. If any adverse reaction is detected after the first session, further use of UV irradiation is not recommended.
Regular irradiation over a long period of time (a year or more) should not exceed 2 sessions per week, and there can be no more than 30 sessions or 30 minimum erythemal doses (MED) per year, no matter how small the erythemal-effective irradiation may be. It is recommended to occasionally interrupt regular radiation sessions.
Therapeutic irradiation must be carried out with the mandatory use of reliable eye protection.
The skin and eyes of any person can become a “target” for ultraviolet radiation. It is believed that people with fair skin are more susceptible to damage, but dark-skinned people may not feel completely safe either.

Very careful with natural and artificial UV exposure of the whole body should be the following categories of people:

Gynecological patients (ultraviolet light can increase inflammation).

Having a large number of birthmarks on the body, or areas of accumulation of birthmarks, or large birthmarks

Have been treated for skin cancer in the past

Working indoors during the week and then sunbathing for long periods of time on the weekends

Living or vacationing in the tropics and subtropics

Those with freckles or burns

Albinos, blondes, fair-haired and red-haired people

Having close relatives with skin cancer, especially melanoma

Living or vacationing in the mountains (every 1000 meters above sea level adds 4% - 5% solar activity)

For long-term stays, due to various reasons, outdoors

Having undergone any organ transplantation

Suffering from certain chronic diseases, such as systemic lupus erythematosus

Receiving the following medications: Antibacterials (tetracyclines, sulfonamides and some others) Nonsteroidal anti-inflammatory drugs, for example, naproxen Phenothiazides, used as sedatives and antinausea agents Tricyclic antidepressants Thiazide diuretics, for example, hypothiazide Sulfourea drugs, tablets that reduce blood glucose Immunosuppressants

Long-term, uncontrolled exposure to ultraviolet radiation is especially dangerous for children and adolescents, as it can cause the development of melanoma, the most rapidly progressing skin cancer, in adulthood.

Water, sunlight and oxygen contained in earth's atmosphere- these are the main conditions for the emergence and factors ensuring the continuation of life on our planet. Moreover, it has long been proven that the spectrum and intensity solar radiation in the vacuum of space are unchanged, but on Earth, the impact of ultraviolet radiation depends on many reasons: time of year, geographic location, altitude, thickness of the ozone layer, cloudiness and the level of concentration of natural and industrial impurities in the air.

What are ultraviolet rays

The sun emits rays in ranges visible and invisible to the human eye. The invisible spectrum includes infrared and ultraviolet rays.

Infrared radiation is electromagnetic waves with a length of 7 to 14 nm, which carry a colossal flow of thermal energy to the Earth, and therefore they are often called thermal. The share of infrared rays in solar radiation is 40%.

Ultraviolet radiation is a spectrum of electromagnetic waves, the range of which is divided conventionally into near and far ultraviolet rays. Distant or vacuum rays are completely absorbed by the upper layers of the atmosphere. Under terrestrial conditions, they are artificially generated only in vacuum chambers.

Near ultraviolet rays are divided into three subgroups of ranges:

• long – A (UVA) from 400 to 315 nm;
• medium – B (UVB) from 315 to 280 nm;
• short – C (UVC) from 280 to 100 nm.

How is ultraviolet radiation measured? Today, there are many special devices, both for domestic and professional use, that allow you to measure the frequency, intensity and magnitude of the received dose of UV rays, and thereby assess their likely harmfulness to the body.

Despite the fact that ultraviolet radiation contains sunlight occupies only about 10%, it was thanks to its influence that a qualitative leap occurred in the evolutionary development of life - the emergence of organisms from water to land.

Main sources of ultraviolet radiation

The main and natural source of ultraviolet radiation is, of course, the Sun. But man has also learned to “produce ultraviolet light” using special lamp devices:

• high-pressure mercury-quartz lamps operating in the general range of UV radiation - 100-400 nm;
• vital fluorescent lamps, generating wavelengths from 280 to 380 nm, with a maximum emission peak between 310 and 320 nm;
• ozone and non-ozone (with quartz glass) bactericidal lamps, 80% of ultraviolet rays of which are at a length of 185 nm.

Both ultraviolet radiation from the sun and artificial ultraviolet light have the ability to affect the chemical structure of cells of living organisms and plants, and at the moment, only some species of bacteria are known that can do without it. For everyone else, the lack of ultraviolet radiation will lead to inevitable death.

So what is the real biological effect of ultraviolet rays, what are the benefits and is there any harm from ultraviolet radiation for humans?

The effect of ultraviolet rays on the human body

The most insidious ultraviolet radiation is short-wave ultraviolet radiation, since it destroys all types of protein molecules.

So why is terrestrial life possible and continuing on our planet? What layer of the atmosphere blocks harmful ultraviolet rays?

Living organisms are protected from hard ultraviolet radiation by the ozone layers of the stratosphere, which completely absorb rays in this range, and they simply do not reach the surface of the Earth.

Therefore, 95% of the total mass of solar ultraviolet comes from long waves (A), and approximately 5% from medium waves (B). But it’s important to clarify here. Despite the fact that there are many more long UV waves and they have great penetrating power, affecting the reticular and papillary layers of the skin, it is the 5% of medium waves that cannot penetrate beyond the epidermis that have the greatest biological impact.

It is mid-range ultraviolet radiation that intensively affects the skin, eyes, and also actively affects the functioning of the endocrine, central nervous and immune systems.

On the one hand, ultraviolet irradiation can cause:

• severe sunburn of the skin - ultraviolet erythema;
• clouding of the lens leading to blindness - cataracts;
• skin cancer – melanoma.

In addition, ultraviolet rays have a mutagenic effect and cause disruptions in the functioning of the immune system, which cause the occurrence of other oncological pathologies.

On the other hand, it is the effect of ultraviolet radiation that has a significant impact on the metabolic processes occurring in the human body as a whole. The synthesis of melatonin and serotonin increases, the level of which has a positive effect on the functioning of the endocrine and central nervous systems. Ultraviolet light activates the production of vitamin D, which is the main component for the absorption of calcium, and also prevents the development of rickets and osteoporosis.

Ultraviolet irradiation of the skin

Skin lesions can be both structural and functional in nature, which, in turn, can be divided into:

1. Acute injuries- arise due to high doses of solar radiation from mid-range rays received in a short time. These include acute photodermatosis and erythema.
2. Delayed damage– occur against the background of prolonged irradiation with long-wave ultraviolet rays, the intensity of which, by the way, does not depend on the time of year or the time of daylight. These include chronic photodermatitis, photoaging of the skin or solar geroderma, ultraviolet mutagenesis and the occurrence of neoplasms: melanoma, squamous cell and basal cell skin cancer. Among the list of delayed injuries is herpes.

It is important to note that both acute and delayed damage can be caused by excessive exposure to artificial sunbathing, not wearing sunglasses, as well as by visiting solariums that use uncertified equipment and/or do not carry out special preventive calibration of ultraviolet lamps.

Skin protection from ultraviolet radiation

If you do not abuse any “sunbathing”, then human body will cope with radiation protection on its own, because more than 20% is retained by healthy epidermis. Today, protection from ultraviolet radiation of the skin comes down to the following techniques that minimize the risk of the formation of malignant neoplasms:

• limiting time spent in the sun, especially during midday summer hours;
• wearing light but closed clothing, because to receive the necessary dose that stimulates the production of vitamin D, it is not at all necessary to cover yourself with a tan;
• selection of sunscreens depending on the specific ultraviolet index characteristic of the area, time of year and day, as well as your own skin type.

Attention! For indigenous people middle zone Russia, a UV index above 8 does not simply require the use of active protection, but also represents real threat for good health. Radiation measurements and solar indices forecasts can be found on leading weather websites.

Exposure to ultraviolet radiation on the eyes

Damage to the structure of the eye cornea and lens (electro-ophthalmia) is possible with visual contact with any source of ultraviolet radiation. Despite the fact that a healthy cornea does not transmit and reflects 70% of hard ultraviolet radiation, there are many reasons that can become a source of serious diseases. Among them:

• unprotected observation of flares, solar eclipses;
• a casual glance at the luminary sea ​​coast or in high mountains;
• photo injury from camera flash;
• observing the operation of a welding machine or neglecting safety precautions (lack of a protective helmet) when working with it;
• long-term operation of the strobe light in discos;
• violation of the rules for visiting a solarium;
• long-term stay in a room in which quartz bactericidal ozone lamps operate.

What are the first signs of electroophthalmia? Clinical symptoms, namely redness of the eye sclera and eyelids, pain when moving the eyeballs and the sensation of a foreign body in the eye, as a rule, occur 5-10 hours after the above circumstances. However, means of protection against ultraviolet radiation are available to everyone, because even ordinary glass lenses do not transmit most UV rays.

The use of safety glasses with a special photochromic coating on the lenses, the so-called “chameleon glasses,” will be the best “household” option for eye protection. You won't have to worry about wondering what color and shade level of UV filter actually provides effective protection in specific circumstances.

And of course, if you expect eye contact with ultraviolet flashes, it is necessary to wear protective glasses in advance or use other devices that block rays harmful to the cornea and lens.

Application of ultraviolet radiation in medicine

Ultraviolet light kills fungus and other microbes in the air and on the surface of walls, ceilings, floors and objects, and after exposure to special lamps, mold is removed. People use this bactericidal property of ultraviolet light to ensure the sterility of manipulation and surgical rooms. But ultraviolet radiation in medicine is used not only to combat hospital-acquired infections.

The properties of ultraviolet radiation have found their application in a wide variety of diseases. At the same time, new techniques are emerging and constantly being improved. For example, ultraviolet blood irradiation, invented about 50 years ago, was initially used to suppress the growth of bacteria in the blood during sepsis, severe pneumonia, extensive purulent wounds and other purulent-septic pathologies.

Today, ultraviolet irradiation of blood or blood purification helps fight acute poisoning, drug overdose, furunculosis, destructive pancreatitis, obliterating atherosclerosis, ischemia, cerebral atherosclerosis, alcoholism, drug addiction, acute mental disorders and many other diseases, the list of which is constantly expanding .

Diseases for which the use of ultraviolet radiation is indicated, and when any procedure with UV rays is harmful:

INDICATIONS	CONTRAINDICATIONS
sun starvation, rickets	individual intolerance
wounds and ulcers	oncology
frostbite and burns	bleeding
neuralgia and myositis	hemophilia
psoriasis, eczema, vitiligo, erysipelas	ONMK
respiratory diseases	photodermatitis
diabetes	renal and liver failure
adnexitis	malaria
osteomyelitis, osteoporosis	hyperthyroidism
non-systemic rheumatic lesions	heart attacks, strokes

In order to live without pain, people with joint damage will benefit from an ultraviolet lamp as an invaluable aid in general complex therapy.

The influence of ultraviolet radiation in rheumatoid arthritis and arthrosis, the combination of ultraviolet therapy techniques with the correct selection of biodose and a competent antibiotic regimen is a 100% guarantee of achieving a systemic health effect with a minimal drug load.

In conclusion, we note that positive influence ultraviolet radiation on the body and just one single procedure of ultraviolet irradiation (purification) of the blood + 2 sessions in a solarium will help a healthy person look and feel 10 years younger.

Ultraviolet radiation from the Sun and artificial sources, depending on the wavelength, is divided into three ranges:

• - region A – wavelength 400-320 nm (long-wave ultraviolet UV-A radiation);
• - region B – wavelength 320-275 nm (mid-wave ultraviolet radiation UV-B);
• - region C – wavelength 275-180 nm (short-wave ultraviolet radiation UV-C).

There are significant differences in the effects of long, medium and short wave radiation on cells, tissues and the body.

Region A (UV-A) long-wave radiation has a variety of biological effects, causing skin pigmentation and fluorescence of organic substances. UV-A rays have the greatest penetrating power, which allows some atoms and molecules of the body to selectively absorb the energy of UV radiation and enter an unstable excited state. The subsequent transition to the initial state is accompanied by the release of light quanta (photons) capable of initiating various photochemical processes, primarily affecting DNA, RNA, and protein molecules.

Phototechnical processes cause reactions and changes on the part of various organs and systems, which form the basis for the physiological and therapeutic effects of UV rays. The shifts and effects that occur in an organism irradiated with UV rays (photoerythema, pigmentation, desensitization, bactericidal effect, etc.) have a clear spectral dependence (Fig. 1), which serves as the basis for the differentiated use of different parts of the UV spectrum.

Figure 1 - Spectral dependence of the most important biological effects of ultraviolet radiation

Irradiation with mid-wave UV rays causes protein photolysis with the formation of biologically active substances, and exposure to short-wave rays more often leads to coagulation and denaturation of protein molecules. Under the influence of UV rays in the B and C ranges, especially in high dosages, changes occur in nucleic acids, which may result in the occurrence of cellular mutations.

At the same time, long-wave rays lead to the formation of a specific photoreactivation enzyme that promotes the restoration of nucleic acids.

1. UV radiation is most widely used for medicinal purposes.
2. UV rays are also used to sterilize and disinfect water, air, premises, objects, etc.
3. Their use for preventive and cosmetic purposes is very common.
4. UV radiation is also used for diagnostic purposes, to determine the reactivity of the body, in luminescent methods.

UV radiation is a vital factor, and its long-term deficiency leads to the development of a peculiar symptom complex, such as “light starvation” or “UV deficiency”. Most often it is manifested by the development of vitamin D deficiency, weakening of the body’s protective immunobiological reactions, exacerbation of chronic diseases, functional disorders of the nervous system, etc. Contingents experiencing “UV deficiency” include workers in mines, mines, subways, people working in lampless and windowless workshops, engine rooms and in the Far North.

Ultraviolet irradiation

Ultraviolet irradiation is produced by various artificial products with different wavelengths λ. The absorption of UV rays is accompanied by a number of primary photochemical and photophysical processes, which depend on their spectral composition and determine the physiological and therapeutic effect of the factor on the body.

Long wave ultraviolet(DUV) rays stimulate the proliferation of cells of the Malpighian layer of the epidermis and the decarboxylation of tyrosine with the subsequent formation of the spinous layer in the cells. Next comes stimulation of the synthesis of ACTH and other hormones, etc. Various immunological changes are obtained.

DUV rays have a weaker biological, including erythema-forming, effect than other UV rays. To increase skin sensitivity to them, photosensitizers are used, most often compounds of the furocoumarin series (puvalene, beroxan, psoralen, amminofurin, etc.)

This property of long-wave radiation allows it to be used in the treatment of skin diseases. PUVA therapy method (salicylic alcohol is also used).

Thus, we can highlight the main characteristics therapeutic effects DUV rays:

1. The therapeutic effects are

• - photosensitizing,
• - pigment-forming,
• - immunostimulating.

1. DUV rays, like other areas of UV radiation, cause changes in the functional state of the central nervous system and its higher part of the cerebral cortex. Due to the reflex reaction, blood circulation improves, the sectoral activity of the digestive organs and the functional state of the kidneys increase.
2. DUV rays affect metabolism, primarily mineral and nitrogen.
3. Local applications of photosensitizers are widely used for limited forms of psoriasis. Recently, UV-B has been successfully used as a sensitizer as it has greater biological activity. Combined irradiation with UV-A and UV-B is called selective irradiation.
4. DUV rays are used for both local and general irradiation. The main indications for their use are:

• - skin diseases (psoriasis, eczema, vitiligo, seborrhea, etc.)
• - chronic inflammatory diseases of internal organs (especially respiratory organs)
• - diseases of the organs of support and movement of various ethnologies
• - burns, frostbite
• - slow-healing wounds and ulcers, cosmetic purposes.

Contraindications

• - acute anti-inflammatory processes,
• - diseases of the liver and kidneys with severe impairment of their functions,
• - hyperthyroidism,
• - increased sensitivity to DUV radiation.

Midwave ultraviolet(SUV) radiation has a pronounced and versatile biological effect.

When ultraviolet radiation quanta are absorbed in the skin, low molecular weight products of protein photolysis and lipid peroxidation products are formed. They cause changes in the ultrastructural organization of biological membranes, protein-lipid complexes, membrane enzymes and their most important physicochemical and functional properties.

Photodecomposition products activate the mononuclear phagocyte system and cause degranulation of mast cells and basophils. As a result, biologically active substances (kinin, prostaglandin, heparin, leukotrienes, thromboxanes, etc.) and vasoactive mediators (acetylcholine, histamine) are released in the irradiated area and adjacent tissues, which significantly increase vascular permeability and tone, and also promote relaxation of smooth muscles . Due to humoral mechanisms, the number of functioning skin capillaries increases, the speed of local blood flow increases, which leads to the formation erythoma.

Repeated SUV irradiation can lead to the appearance of quickly disappearing pigmentation, which helps improve the barrier function of the skin, increases its cold sensitivity and resistance to the effects of toxic substances and adverse factors.

Both the erythemal reaction and other changes caused by SUV rays depend not only on the wavelength, but also on the dosage. In phototherapy it is used in erythemal and suberythemal doses.

Irradiation with SUV rays in suberythemal dosages promotes the formation of vitamin D in the skin, which, after its biotransformation in the liver and kidneys, is involved in the regulation of phosphorus-calcium metabolism in the body. SUV irradiation promotes the formation of not only vitamin D1, but also its isomer, ergocalcifemin (vitamin D2). The latter has an antirachitic effect and stimulates the aerobic and anaerobic pathways of cellular respiration. SUV rays in small dosages also modulate the metabolism of other vitamins (A and C) and cause activation of metabolic processes in irradiated tissues. Under their influence, the adaptive-trophic function of the sympathetic nervous system is activated, disturbed processes are normalized various types metabolism, cardiovascular activity.

Thus, SUV radiation has a pronounced biological effect. Depending on the phase of irradiation, you can get erythema on the skin and mucous membranes or carry out treatment at a dose that does not cause it. The mechanism of therapeutic action of erythema and non-erythema doses of SUF is different, therefore the indications for the use of ultraviolet radiation will be different.

Ultraviolet erythema appears at the site of UV-B irradiation after 2-8 hours and is associated with the death of epidermal cells. The products of protein photolysis enter the bloodstream and cause vasodilation, skin swelling, migration of leukocytes, irritation of numerous receptors, leading to a number of reflex reactions of the body.

In addition, photolysis products entering the bloodstream have a humoral effect on individual organs, the nervous and endocrine systems of the body. The phenomena of aseptic inflammation gradually subside by the seventh day, leaving behind skin pigmentation at the site of irradiation.

The main therapeutic effects of SUV radiation:

1. SUV radiations are vitamin forming, trophostimulating, immunomodulating - these are suberythemal doses.
2. Anti-inflammatory, analgesic, desensitizing - this is an erythemal dose.
3. Bronchial diseases, asthma, hardening - this is an erythema-free dose.

Indications for topical use of UV-B (suberythemal and erythemal doses):

• - acute neuritis
• - acute meositis
• - pustular skin diseases (furucle, carbuncle, sycosis, etc.)
• - erysipelas
• - trophic ulcers
• - slow-healing wounds
• - bedsores
• - inflammatory and post-traumatic diseases of the joints
• - rheumatoid arthritis
• - bronchial asthma
• - acute and chronic bronchitis
• - acute respiratory diseases
• - inflammation of the uterine appendages
• - chronic tonsillitis.

Erythema-free zones of ultraviolet B radiation during general irradiation of the body eliminate the phenomena of D-hypovitaminosis associated with a lack of sunlight. Normalizes phosphorus-calcium metabolism, stimulates the function of the sympathetic-adrenal and pituitary-adrenal systems, increases the mechanical strength of bone tissue and stimulates the formation of callus, increases the resistance of the body’s skin and the body as a whole to harmful factors external environment. Allergic and exudative reactions decrease, mental and physical performance increases. Other disorders in the body caused by sun starvation are weakened.

Indications for general use of UV-B (non-erythema doses):

• - D-hypovitaminosis
• - metabolic disease
• - predisposition to pustular diseases
• - neurodermatitis
• - psoriasis
• - bone fractures and impaired callus formation
• - bronchial asthma
• - chronic diseases of the bronchial apparatus
• - hardening of the body.

Contraindications:

• - malignant neoplasms
• - tendency to bleed
• - system blood diseases
• - thyrotoxicosis
• - active tuberculosis
• - peptic ulcer stomach and duodenum in the acute stage
• - hypertension stages II and III
• - advanced atherosclerosis of the cerebral arteries and coronary arteries.

Short-wave ultraviolet radiation spectrum(UV) radiation.

Short-wave UV radiation is an active physical factor, since its quanta have the greatest energy reserve. It is capable of causing denaturation and photolysis of nucleic acids and proteins due to excessive absorption of the energy of its quanta different molecules, primarily DNA and RNA.

When acting on microorganisms or cells, this leads to inactivation of their genome and protein denaturation, which leads to their death.

When HF rays are emitted, a bactericidal effect occurs, since their direct contact with protein is fatal to viral cells, microorganisms and fungi.

AF rays cause, after a short-term spasm, dilation of blood vessels, primarily subcapellar veins.

Indications for the use of EF radiation:

• - irradiation of wound surfaces
• - bedsores and almond-shaped niches after tonsillectomy with a bactericidal chain
• - rehabilitation of the nasopharynx in acute respiratory diseases
• - treatment of external otitis
• - air disinfection in operating rooms, treatment rooms, inhalations, intensive care units, patient wards, children's institutions and schools.

Skin and its function

Human skin makes up 18% of the human body weight and has a total area of ​​2 m2. The skin consists of three anatomically and physiologically closely interconnected layers:

• - epidermis or cutis
• - dermis (actual skin)
• - hypodermis (subcutaneous fat lining).

The epidermis is built from different in shape and structure, layer-by-layer epithelial cells (epithermocytes). Moreover, each overlying cell comes from the underlying one, reflecting a certain phase of its life.

The layers of the epidermis are located in the following sequence (from bottom to top):

• - basal (D) or germinal;
• - layer of spinous cells;
• - layer of keratohyaline or granular cells;
• - epeidine or shiny;
• - horny.

In addition to epidermocytes, the epidermis (in the basal layer) contains cells capable of producing melanin (melanocytes), Lagerhans cells, Greenstein cells, etc.

The dermis is located directly below the epidermis and is separated from it by the main membrane. The dermis is divided into papillary and reticular layers. It consists of collagen, elastic and reticulin (argyrophilic) fibers, between which the main substance is located.

In the dermis, in fact, in the skin there is a papillary layer, richly supplied with blood and lymphatic vessels. There are also plexuses of nerve fibers that give rise to numerous nerve endings in the epidermis and dermis. The dermis contains sweat and sebaceous glands and hair follicles at various levels.

Subcutaneous fat is the deepest layer of the skin.

The functions of the skin are complex and varied. The skin performs barrier - protective, thermoregulatory, excretory, metabolic, receptor, etc.

The barrier-protective function, considered the most important function of human and animal skin, is carried out through various mechanisms. Thus, the strong and elastic stratum corneum of the skin resists mechanical influences and reduces the harmful effects of chemicals. The stratum corneum, being a poor conductor, protects the deeper layers from drying out, cooling and the action of electric current.

Figure 2 – Skin structure

Sebum, the secretion product of sweat glands and scales of exfoliating epithelium form an emulsion film (protective mantle) on the surface of the skin, which plays an important role in protecting the skin from the effects of chemical, biological and physical agents.

The acidic reaction of the water-lipid mantle and surface layers of the skin, as well as the bactericidal properties of skin secretions, are an important barrier mechanism for microorganisms.

The pigment melanin plays a certain role in protecting against light rays.

The electrophysiological barrier is the main obstacle to the penetration of substances deep into the skin, including during electrophoresis. It is located at the level of the basal layer of the epidermis and is an electrical layer with heterogeneous layers. Due to the acidic reaction, the outer layer has a “+” charge, and the one facing inward has a “-”. It should be borne in mind that, on the one hand, the barrier-protective function of the skin weakens the effect of physical factors on the body, and on the other hand, physical factors can stimulate the protective properties of the skin and thereby realize therapeutic effects.

Physical thermoregulation The body is also one of the most important physiological functions of the skin and is directly related to the mechanism of action of hydrotherapeutic factors. It is carried out by the skin by heat radiation in the form of infrared rays (44%), heat conduction (31%) and evaporation of water from the surface of the skin (21%). It is important to note that the skin, with its thermoregulatory mechanisms, plays a large role in acclimatization of the body.

Secret-excretory function skin is associated with the activity of the sweat and sebaceous glands. It plays an important role in maintaining the homeostasis of the body and in providing the skin with barrier properties.

Respiratory and resorption function are closely interconnected. The respiratory function of the skin, which consists of absorbing oxygen and releasing carbon dioxide, is not of great importance in the overall balance of respiration for the body. However, skin respiration may increase significantly under conditions high temperature air.

The resorption function of the skin and its permeability are of great importance not only in dermatology and toxicology. Its significance for physiotherapy is determined by the fact that the chemical component of the action of many therapeutic factors (medicinal, gas and mineral baths, mud therapy, etc.) depends on the penetration of their constituent ingredients through the skin.

Exchange function skin has specific characteristics. On the one hand, only the metabolic processes inherent to it occur in the skin (formation of keratin, melanin, vitamin D, etc.), on the other hand, it takes an active part in the general metabolism in the body. Its role is especially great in fat, mineral, carbohydrate and vitamin metabolism.

The skin is also the site of synthesis of biologically active substances (heparin, histamine, serotonin, etc.).

Receptor function skin provides its connection with the external environment. The skin performs this function in the form of numerous conditioned and unconditioned reflexes due to the presence of the various receptors mentioned above.

It is believed that per 1 cm2 of skin there are 100-200 pain points 12-15 cold, 1-2 heat, 25 pressure points.

Relationship with internal organs is closely related - changes in the skin affect the activity of internal organs, and disorders of the internal organs are accompanied by changes in the skin. This relationship is especially clearly manifested in internal diseases in the form of the so-called reflexogenic, or pain, zones of Zakharin-Ged.

Zakharyin-Ged zone certain areas of the skin in which, due to diseases of the internal organs, reflected pain often appears, as well as pain and temperature hyperesthesia.

Figure 3 – Location of the Zakharyin-Ged zone

Such zones for diseases of internal organs have also been identified in the head area. For example, pain in frontonasal region corresponds to damage to the apices of the lungs, stomach, liver, and aortic mouth.

Pain in the mid-orbital region damage to the lungs, heart, ascending aorta.

Pain in the frontotemporal region damage to the lungs and heart.

Pain in the parietal region damage to the pylorus and upper intestine, etc.

Comfort zone the region of temperature conditions of the external environment that cause a person to have a subjectively good feeling of heat without signs of cooling or overheating.

For a naked person 17.3 0С – 21.7 0С

For a dressed person 16.7 0С – 20.6 0С

Pulsed ultraviolet therapy

Research Institute of Energy Mechanical Engineering MSTU named after. N. E. Bauman (Shashkovsky S. G. 2000) developed a portable device “Melitta 01” for local irradiation of the affected surfaces of the skin, mucous membranes with highly effective pulsed ultraviolet radiation of a continuous spectrum in the range of 230-380 nm.

The operating mode of this device is pulse-periodic with a frequency of 1 Hz. The device provides automatic generation of 1, 4, 8, 16, 32 pulses. Output pulse power density at a distance of 5 cm from the burner 25 W/cm2

Indications:

• - purulent-inflammatory diseases of the skin and subcutaneous tissue (furuncle, carbuncle, hidradenitis) in initial period hydration and after surgical opening of the purulent cavity;
• - extensive purulent wounds, wounds after necrectomy, wounds before and after autodermoplasty;
• - granulating wounds after thermal, chemical, radiation burns;
• - trophic ulcers and slow-healing wounds;
• - erysipelas;
• - herpetic inflammation of the skin and mucous membranes;
• - irradiation of wounds before and after primary surgical treatment in order to prevent the development of purulent complications;
• - disinfection of indoor air, car interior, bus and ambulance air.

Pulse magnetic therapy with rotating field and changing pulse repetition rate automatically.

The therapeutic effect is based on well-known physical laws. An electric charge moving through a blood vessel in a magnetic field is affected by the Lorentz force, perpendicular to the charge velocity vector, constant in a constant and alternating in an alternating, rotating magnetic field. This phenomenon is realized at all levels of the body (atomic, molecular, subcellular, cellular, tissue).

The action of low-intensity pulsed magnetic therapy has an active effect on deep-lying muscle, nervous, bone tissue, and internal organs, improving microcirculation, stimulating metabolic processes and regeneration. High-density electric currents induced by pulsed magnetic field, I activate the myelinated thick fibers of the nerves, as a result of which afferent impulses from the pain site are blocked through the spinal “gate block” mechanism. The pain syndrome is weakened or eliminated completely during the procedure or after the first procedures. In terms of the severity of the analgesic effect, pulsed magnetic therapy is far superior to other types of magnetic therapy.

Thanks to pulsed rotating magnetic fields, it becomes possible to indicate electric fields and currents of significant intensity in the depths of tissues without damaging them. This makes it possible to obtain pronounced therapeutic anti-edematous, analgesic, anti-inflammatory, stimulating regeneration processes, biostimulating effects, which are several times more pronounced than the therapeutic effects obtained from all known low-frequency magnetic therapy devices.

Pulse magnetic therapy devices are a modern effective means of treating traumatic injuries, inflammatory, degenerative-dystrophic diseases of the nervous and musculoskeletal systems.

Therapeutic effects of pulsed magnetic therapy: analgesic, decongestant, anti-inflammatory, vasoactive, stimulating regeneration processes in damaged tissues, neurostimulating, myostimulating.

Indications:

• – diseases and traumatic injuries of the central nervous system (ischemic stroke of the brain, transient cerebrovascular accident, consequences of traumatic brain injury with movement disorders, closed spinal cord injuries with motor disorders, cerebral palsy, functional hysterical paralysis),
• - traumatic injuries of the musculoskeletal system (bruises of soft tissues, joints, bones, sprains, closed fractures of bones and joints during immobilization, in the stage of reparative regeneration, open fractures of bones, joints, soft tissue injuries during immobilization, in the stage of reparative regeneration, malnutrition , muscle atrophy as a result of physical inactivity caused by traumatic injuries of the musculoskeletal system),
• - inflammatory degenerative-dystrophic injuries of the musculoskeletal system (deforming osteoarthritis of the joints with symptoms of synovitis and without symptoms of synovitis, widespread osteochondrosis, deforming spondylosis of the spine with phenomena of secondary radicular syndrome, cervical radiculitis with phenomena of scapulohumeral hyperatritis, thoracic radiculitis, lumbosacral radiculitis, ankylosing spondyloatritis, scoliotic disease in children),
• - surgical inflammatory diseases (postoperative period after surgical interventions on the musculoskeletal system, skin and subcutaneous tissue, sluggish wounds, trophic ulcers, boils, carbuncles, phlegmon after surgery, mastitis),
• - diseases of the bronchopulmonary system (mild to moderate bronchial asthma, chronic bronchitis),
• - diseases of the digestive system (hypomotor-evacuation dysfunction of the stomach after stomach and vagotomy, hypomotor dysfunction of the colon, stomach and gall bladder, chronic hepatitis with moderate liver dysfunction, chronic pancreatitis with secretory insufficiency),
• - diseases of the cardiovascular system (occlusive lesions of peripheral arteries of atherosclerotic origin),
• - urological diseases (stone in the ureter, condition after lithotripsy, atony of the bladder, weakness of the sphinker and detrusor, prostatitis),
• - gynecological diseases (inflammatory diseases of the uterus and appendages, diseases caused by ovarian hypofunction),
• - chronic prostatitis and sexual disorders in men,
• - dental diseases (periodontal disease, filling pain).

Contraindications:

• - severe hypotension,
• - systemic blood diseases,
• - tendency to bleed,
• - thrombophlebitis,
• - thromboembolic disease, bone fractures before immobilization,
• - pregnancy,
• - thyrotoxicosis and nodular goiter,
• - abscess, phlegmon (before opening and draining the cavities),
• - malignant neoplasms,
• - feverish condition,
• - cholelithiasis,
• - epilepsy.

Warning:

Pulsed magnetic therapy cannot be used in the presence of an implanted pacemaker, since the induced electrical potentials may interfere with its function; with various metal objects lying freely in the tissues of the body (for example, fragments from wounds), if they are located at a distance of less than 5 cm from the inductors, since when passing magnetic field pulses, objects made of electrically conductive materials (steel, copper, etc.) can move and cause damage to surrounding tissues. It is not allowed to affect the area of ​​the brain, heart and eyes.

Of great interest is the creation of low-intensity pulsed magnetic devices (20-150 mT) with a pulse repetition rate approximately coinciding with the frequency of the organs’ own biopotentials (2-4-6-8-10-12 Hz). This would make it possible to exert a bioresonance effect on internal organs (liver, pancreas, stomach, lungs) with a pulsed magnetic field and have a positive effect on their function. It is already known that UTI at a frequency of 8-10 Hz has a positive effect on liver function in patients with toxic (alcoholic) hepatitis.

The ultraviolet range of electromagnetic radiation lies beyond the violet (short wavelength) end of the visible spectrum.

Near ultraviolet light from the Sun passes through the atmosphere. It causes tanning on the skin and is necessary for the production of vitamin D. But excessive exposure can lead to the development of skin cancer. UV radiation is harmful to the eyes. Therefore, it is imperative to wear safety glasses on water and especially on snow in the mountains.

Harsher UV radiation is absorbed in the atmosphere by molecules of ozone and other gases. It can only be observed from space, and therefore it is called vacuum ultraviolet.

The energy of ultraviolet quanta is sufficient to destroy biological molecules, in particular DNA and proteins. One of the methods for destroying microbes is based on this. It is believed that as long as there was no ozone in the Earth's atmosphere, which absorbs a significant part of ultraviolet radiation, life could not leave the water on land.

Ultraviolet light is emitted by objects with temperatures ranging from thousands to hundreds of thousands of degrees, such as young, hot, massive stars. However, UV radiation is absorbed by interstellar gas and dust, so we often see not the sources themselves, but the cosmic clouds illuminated by them.

Mirror telescopes are used to collect UV radiation, and photomultiplier tubes are used for registration, and in the near UV, as in visible light, CCD matrices are used.

Sources

The glow occurs when charged particles from the solar wind collide with molecules in Jupiter's atmosphere. Most particles, under the influence of the planet's magnetic field, enter the atmosphere near its magnetic poles. Therefore, the glow occurs in a relatively small area. Similar processes are taking place on Earth and on other planets that have an atmosphere and a magnetic field. The image was taken by the Hubble Space Telescope.

Receivers

Hubble Space Telescope

Sky Reviews

The survey was built by the orbiting ultraviolet observatory Extreme Ultraviolet Explorer (EUVE, 1992–2001). The line structure of the image corresponds to the orbital motion of the satellite, and the inhomogeneity of the brightness of individual bands is associated with changes in the calibration of the equipment. Black stripes are areas of the sky that could not be observed. The small number of details in this review is due to the fact that there are relatively few sources of hard ultraviolet radiation and, in addition, ultraviolet radiation is scattered by cosmic dust.

Terrestrial Application

Installation for dosed irradiation of the body with near ultraviolet light for tanning. Ultraviolet radiation leads to the release of melanin pigment in cells, which changes skin color.

Doctors divide near ultraviolet light into three sections: UV-A (400–315 nm), UV-B (315–280 nm) and UV-C (280–200 nm). The mildest ultraviolet UV-A stimulates the release of melanin stored in melanocytes - the cellular organelles where it is produced. The harsher UV-B rays trigger the production of new melanin and also stimulate the production of vitamin D in the skin. Models of tanning beds differ in the power of radiation in these two areas of the UV range.

In sunlight at the Earth's surface, up to 99% of ultraviolet radiation is in the UV-A region, and the rest is in UV-B. Radiation in the UV-C range has a bactericidal effect; in the solar spectrum it is much less than UV-A and UV-B, in addition, most of it is absorbed in the atmosphere. Ultraviolet radiation causes drying and aging of the skin and contributes to the development cancer diseases. Moreover, radiation in the UV-A range increases the likelihood of the most dangerous type of skin cancer - melanoma.

UV-B radiation is almost completely blocked by protective creams, in contrast to UV-A, which penetrates through such protection and even partially through clothing. In general, it is believed that very small doses of UV-B are beneficial to health, and that the rest of the ultraviolet is harmful.

Ultraviolet radiation is used to determine the authenticity of banknotes. Polymer fibers with a special dye are pressed into banknotes, which absorbs ultraviolet quanta and then emits less energetic radiation in the visible range. Under the influence of ultraviolet light, the fibers begin to glow, which serves as one of the signs of authenticity.

The ultraviolet radiation of the detector is invisible to the eye; the blue glow, noticeable when most detectors operate, is due to the fact that the ultraviolet sources used also emit in the visible range.

Over the many years of its development, medicine has achieved significant success. This science widely uses the developments of physicists and chemists in everyday practice, which facilitates the diagnosis of diseases and makes their therapy as effective as possible. Modern methods treatments are now practiced even in small medical institutions; almost every clinic has a special physiotherapeutic treatment room, where many unique devices operate. Doctors widely use ultraviolet radiation in their practice, let's talk about its place in medicine, and discuss the use of ultraviolet radiation in medicine in a little more detail.

Ultraviolet radiation is electromagnetic waves, the length of which ranges from 180 to 400 nm. This physical factor is characterized by many properties and can have a pronounced positive effect on the human body. It is actively used in physiotherapy for more successful treatment of a number of diseases.

Ultraviolet rays can penetrate the skin to a depth of no more than one millimeter, causing a number of different biochemical changes in it. Experts identify several types of such radiation, they can be presented:

Long-wave radiation (wavelength ranges from 320 to 400 nm);
- medium-wave radiation (wavelength indicators are in the range from 275 to 320 nm);
- short-wave radiation (wavelength varies from 180 to 275 nm).

All types of ultraviolet radiation have different influence on the human body.

Long wave radiation

This ultraviolet radiation is characterized by pigmenting qualities. When it comes into contact with the skin, it provokes the development of a number of chemical reactions, which are accompanied by the production of melanin, and the skin appears to tan.

Also, long-wave radiation has a pronounced immunostimulating effect, increasing local immunity and nonspecific resistance of the human body to the aggression of many unfavorable factors.

In addition, this type of ultraviolet irradiation is characterized by photosensitizing properties. Its effect leads to increased skin sensitivity and active production of melanin. Therefore, in people with dermatological diseases, long-wave radiation causes swelling of the skin and erythema. Therapy in this case leads to normalization of pigmentation and structural features of the skin. This type of treatment is classified as photochemotherapy.

Long-wave ultraviolet radiation in medicine is used to treat chronic inflammatory processes of the respiratory system and ailments of the osteoarticular system, which are of an inflammatory nature. This effect is also used in the treatment of burns, frostbite, trophic ulcers and skin diseases such as vitiligo, psoriasis, mycosis fungoides, seborrhea, etc.

Medium wave radiation
This type of ultraviolet therapy has a pronounced immunostimulating effect, promotes the production and absorption of a number of vitamins, and helps eliminate pain and inflammation. In addition, medium-wave radiation is characterized by desensitizing qualities (reduces the body’s sensitivity to the effects of protein photodestruction products) and stimulates trophism (improves blood flow, increases the number of working vessels).

This type of ultraviolet therapy helps to cope with inflammatory lesions of the respiratory system and post-traumatic changes in the musculoskeletal system. It is used in the treatment of inflammatory lesions of bones and joints, represented by arthritis and arthrosis, as well as in the elimination of vertebrogenic radiculopathies, neuralgia, myositis and plexitis. In addition, mid-wave ultraviolet radiation is indicated for patients with sun starvation, metabolic diseases and erysipelas.

Shortwave radiation

This type of ultraviolet radiation has a pronounced bactericidal and fungicidal effect (activates reactions that help destroy the structure of bacteria and fungi), promotes detoxification of the body (helps to produce substances in the body that can neutralize toxins). In addition, short-wave radiation is characterized by metabolic properties - during its implementation, microcirculation improves, as a result of which organs and tissues are saturated with a significant amount of oxygen. This therapy also corrects blood clotting abilities - it changes the ability of blood cells to form blood clots and optimizes coagulation processes.

Short-wave radiation is used in the treatment of a number of skin diseases, including psoriasis, neurodermatitis, and skin tuberculosis. Neem treats various wounds, erysipelas, abscesses, as well as boils and carbuncles. This therapy helps to cope with otitis and tonsillitis, cure osteomyelitis and eliminate long-term non-healing ulcerative lesions on the skin.

Short-wave ultraviolet radiation is used in the complex treatment of rheumatic damage to the heart valves, coronary heart disease, hypertension (first or second degree) and a number of gastrointestinal ailments (ulcerative diseases and gastritis). In addition, this effect helps eliminate acute and chronic respiratory diseases, treat diabetes mellitus, acute andexitis and chronic pyelonephritis.

Like any other effect on the body, ultraviolet radiation has a number of contraindications for use.