Physiological and hygienic significance of the visible spectrum of solar radiation. Solar radiation

Treatment, ped. faculty 2006

LESSON 18

Topic: Microbiological diagnosis of typhoid fever, paratyphoid fevers A and B, salmonellosis.

Target: Based on knowledge of the biology of salmonella - the causative agents of typhoid fever, paratyphoid fevers A, B and foodborne diseases, the peculiarities of their interaction with the macroorganism, be able to substantiate the tactics of microbiological diagnostics, prevention and therapy of the diseases they cause.

Know:

Peculiarities of Salmonella biology that determine their role in human infectious pathology.

Pathogenesis of typhoid fever, paratyphoid A, B, food toxic infections.

Materials and methods for microbiological diagnosis of diseases caused by Salmonella.

Specific prevention and therapy of diseases caused by salmonella.

Be able to:

Take into account and evaluate the results of blood culture on Rappoport medium or bile broth.

Take into account and evaluate the results of sowing an enrichment culture on bismuth sulfite agar (BSA).

To identify the blood culture under study, taking into account morphotinctorial (Gram method), biochemical (primary identification on Kligler’s medium), antigenic (RA with polyvalent salmonella serum of groups A, B, C, D, E) properties.

Take into account and evaluate the results of the “variegated series”, RA with monoreceptor Salmonella O- and H-sera in order to identify and differentiate Salmonella.

Take into account and evaluate the results of Vidal RA, RNGA with erythrocyte Vi-diagnosticum.

Security questions:

Classification and morphobiological properties of Salmonella.

Salmonella virulence factors.

Features of ecology, epidemiology and pathogenesis of typhoid fever, paratyphoid fevers A and B, foodborne toxic infections of salmonella etiology.

Materials and methods for microbiological diagnosis of diseases caused by Salmonella.

Specific prevention and therapy of diseases caused by salmonella.

Tasks performed during the lesson (UIPC):

Conduct a bacteriological blood test to establish the etiology of the disease:

Take into account and evaluate the results of blood culture of a patient with suspected typhoid fever.
Take into account and evaluate the results of sowing the enrichment culture on bismuth-sulfite agar (BCA).

Study the culture isolated from the subject on Kligler’s medium (demonstration) and MPA:

take into account the biochemical activity of the culture on Kligler’s medium;

prepare a fixed preparation from the culture on MPA, Gram stain, microscope;

put and take into account the results of RA on glass with the test culture on MPA and polyvalent salmonella serum of groups A, B, C, D, E;

evaluate the results obtained.

Take into account and evaluate the results of studying biochemical (“variegated series”), antigenic (RA with adsorbed monoreceptor Salmonella O- and H-sera) properties.

Based on the results obtained, draw a conclusion, fill out the direction form and the response form from the tank. laboratories.

Take into account and evaluate the results of Vidal RA with the serum of a subject with suspected typhoid fever and typhoid, paratyphoid A and B diagnosticums.

Take into account and evaluate the results of RNGA with erythrocyte Vi-diagnosticum and sera of subjects from the designated group (food industry workers).

Study and describe in the protocol biological products: adsorbed agglutinating polyvalent groups A, B, C, D, E, monoreceptor O- and H-sera; typhoid bacteriophage; Salmonella bacteriophage; Salmonella diagnosticums, typhoid vaccine.

Methodological instructions for completing the research task:

Carry out a bacteriological examination of the blood of a patient with suspected typhoid fever:

Stage 1. Isolating a blood culture is the earliest and most reliable method for diagnosing typhoid fever, paratyphoid fevers A and B. At the onset of the disease, 5-10 ml of blood from the cubital vein is taken for research, observing the rules of asepsis; at a later date - 15-20 ml. The blood is immediately inoculated onto bile broth or Rappoport medium, maintaining a ratio of blood to nutrient medium of 1:10, to suppress the bactericidal properties of blood. The vials are labeled and kept at room temperature before being transported to the laboratory, but not in the refrigerator! The crops are incubated at 37 for 7 days, the crops being examined every day to detect the presence of growth.

Rules for blood collection: When drawing blood, medical personnel must observe personal protective measures (for example, using rubber gloves) provided for when working with blood. The skin over the punctured vein is thoroughly treated with 70% ethyl alcohol, then 1-2% tincture of iodine for 30 s (from the center of the future puncture towards the periphery). Allow the treated area of skin to dry, then venipuncture is performed, after which the area is again treated with 70% ethyl alcohol to remove excess iodine to avoid skin irritation.

Rappaport's medium contains bile broth, glucose or mannitol, Andrede's indicator and float. It is an accumulation medium for salmonella, as well as a differential diagnostic medium. When typhoid bacteria multiply in Rappoport's medium, as a result of the breakdown of glucose (mannitol) to acid, the color of the medium changes from yellow to red, and in the case of the formation of not only acid, but also gas, which is typical for paratyphoid bacteria, the latter accumulates in the float, displacing part of the nutrient environment. From the accumulation medium, if there are signs of growth, seedings are done on Endo (Levin) medium and, in parallel, on Kligler medium (MPA), since in positive cases, as a rule, a pure culture grows. In case of contamination of the accumulation medium due to violation of the rules for taking blood, Endo medium allows you to isolate a pure culture. Crops are incubated at 37 for 18-24 hours.

Stage 3. Evaluate the results of inoculating the enrichment culture on Endo (Levin) medium, carry out the initial identification of the isolated blood culture, taking into account morphotinctorial, biochemical (on Kligler’s medium) and antigenic properties. To study morphotinctorial and antigenic properties, use a hemoculture on a beveled MPA.

On Kligler's medium S. typhi ferments glucose (mannitol) with the formation of acid (yellowing of the agar column), does not break down lactose (the color of the slanted part of the agar does not change) and produces H 2 S (blackening of the medium). Paratyphoidal salmonella ferment glucose (mannitol) with the formation of acid and gas, so not only the color of the column changes, but it also breaks.

Salmonella are gram-negative polymorphic rods, mostly located solitary in size.

With a pure culture of gram-negative rods grown on regular agar, corresponding in biochemistry to salmonella, place the RA on glass with adsorbed polyvalent salmonella serum of groups A, B, C, D, E (see lesson No. 10). A positive result indicates that the culture belongs to the river. Salmonella. For final identification, the culture is sown in the “variegated row” media and the RA is placed on glass with the corresponding adsorbed monoreceptor O- and H-sera (demonstration).

Stage 4. Consider the results of the “variegated row”. Based on all the results obtained, determine the species of the isolated blood culture; record the results in the protocol, fill out the referral form and the response form from the tank. laboratories.

When serodiagnosis of typhoid fever and paratyphoid fevers A and B, Vidal RA is placed simultaneously with 4 diagnosticums: O- and H-typhoid fever, A- and B-paratyphoid fever. This is due to the fact that clinically typhoid fever, paratyphoid fever A and B are practically no different. Therefore, identifying specific antibodies makes it possible to establish the etiology of the disease.

When interpreting the results of Vidal RA, it is necessary to remember that the reaction can be positive not only in patients (infectious Vidal), but also in any febrile state, if the patient has previously suffered from typhoid fever (anamnestic Vidal) and in vaccinated people (vaccine Vidal). Widal RA can also be of a group nature, since the patient’s serum contains antibodies not only to specific, but also to group antigens. The criterion for differentiating infectious Widal is the detection of an increase in the titer of specific antibodies by 2 or more times when studying paired sera.

In addition, differentiated determination of O- and H-antibodies makes it possible to establish the period of development of the disease, since O-antibodies accumulate at the height of the disease, and H-antibodies during the period of convalescence.

The criterion for assessing the results of Widal RA with a single serum taken is a diagnostic titer equal to 1:200 in unvaccinated adults, and 1:100 in unvaccinated children (see lesson No. 10).

RNGA with erythrocyte Vi-diagnosticum is most often used to detect bacterial carriage S. typhi. The diagnostic titer when assessing the results is 1:40 (see lesson No. 10).

Rapoport Wednesday Rapoport Wednesday

enrichment medium used to isolate Salmonella from blood. To make it, 2% glucose (previously diluted in 5 ml of distilled water) and 1% Andrade indicator (or 0.1% bromocresol purple) are added to 10% bile broth with pH 7.2. The mixture is poured into 50 ml bottles with floats measuring 60x8 mm. Sterilize for 3 days for 30 minutes with running steam. Inoculate 5-10 ml of freshly drawn blood. Incubate at 37°C for several days. When Salmonella grows, the medium becomes cloudy and turns red or yellow, gas may appear in the float. Subculture on Endo, Russell, Olkenitsky media.

(Source: Dictionary of Microbiology Terms)

See what “Rapoport Wednesday” is in other dictionaries:

- (M. A. Rapoport) solid selective differential diagnostic nutrient medium for the isolation of enterobacteria, containing glycerin, ox bile and acid fuchsin... Large medical dictionary

- (M. A. Rapoport; A. Weintraub) liquid selective nutrient medium for isolating typhoid pathogens from the blood, containing meat-peptone broth, bile, Andrade indicator, glucose or mannitol... Large medical dictionary

- artificial substrate, which is a balanced mixture nutrients in concentrations and combinations necessary for the growth and division of microorganisms or cells of higher organisms. Adams's nutrient medium see Adams... ... Medical encyclopedia

See Rapoport Wednesday... Large medical dictionary

See Rapoport Weintraub Wednesday... Large medical dictionary

- (M.A. Rapoport; A. Weintraub) liquid selective nutrient medium for isolating typhoid pathogens from the blood, containing meat-peptone broth, bile, Aidrade indicator, glucose or mannitol... Medical encyclopedia

- (M.A. Rapoport) solid selective differential diagnostic nutrient medium for the isolation of enterobacteria, containing glycerol, ox bile and acid fuchsinone... Medical encyclopedia

- (systems theory) scientific and methodological concept of studying objects that are systems. It is closely related to the systems approach and is a concretization of its principles and methods. The first version of general systems theory was... ... Wikipedia

PARATYPHOID- PARATYPHUS. Contents: Bacteriology ♦ .................. 719 Epidemiology.................. 727 Etiology...... .............. 728 Statistics. .................... 729 Pathogenesis.................... 732 Pathological anatomy..... .......… … Great Medical Encyclopedia

Benzion (Boris) Zakharovich Milner Benzion Milner Date of birth: November 10, 1929 (1929 11 10) (83 years old) Place of birth: Cherkasy, Ukrainian SSR, USSR ... Wikipedia

The normal functioning of the body and its performance are closely related to air, its physical properties and chemical composition. The air environment is a necessary condition for life on Earth. She's playing important role in the respiration of humans, animals and plants. Without air, maintaining the vitality of the body is unthinkable. The role of air is to supply oxygen, remove metabolic products, and ensure the heat exchange process.

The role of the air environment in human production activity is great. It is a reservoir of toxic and microbial contaminants (harmful gases, suspended particles, various microorganisms) that can adversely affect the body.

During the course of evolution, man was prepared by nature to perceive the effects of various environmental factors. Drastic changes physical properties And chemical composition adversely affect the most important functions of the body and lead to various diseases.

The main factors of the air environment that influence human life, well-being and performance include: physical - solar radiation, temperature, humidity, air speed, barometric pressure, electrical state, radioactivity; chemical - content of oxygen, nitrogen, carbon dioxide and others components and impurities; mechanical pollutants - dust, smoke, as well as microorganisms.

The listed factors, both in aggregate and each individually, can have an impact on adverse influence on the body. Therefore, hygiene is faced with the task of studying their positive and negative impact and develop measures to use the positive properties ( sunbathing, hardening procedures, etc.), and for prevention harmful influence (sunburn, overheating, etc.)

Solar radiation is the only source of energy, heat and light on Earth. The sun has a hugely diverse influence on the processes occurring in the organic and inorganic world. Thanks to solar radiation, the surface of the globe heats up, water evaporates, air masses move, and the weather changes. It is the main factor

By solar radiation we mean the entire integral flux of radiation emitted by the Sun, which represents electromagnetic oscillations of various wavelengths. The bulk of the solar spectrum consists of rays with extremely short wavelengths, which are measured in nanometers (nm). From a hygienic point of view, the optical part is of particular interest sunlight, which occupies the range from 280-2800 nm. Longer waves are radio waves, shorter ones are gamma rays, ionizing radiation does not reach the surface of the Earth, because when passing through the air envelope they are delayed, losing up to 57% of the original power, in the ozone layer in particular. Ozone is distributed throughout the atmosphere, but at an altitude of about 35 km it forms the ozone layer.

The intensity of solar rays at noon in May in Yalta is 1.33, in Moscow 1.28, in Irkutsk 1.30, in Tashkent 1.34.

Table 1 - The ratio of direct and diffuse solar radiation at different heights of the Sun above the horizon (according to N.N. Kalitin)

Thus, the same solar radiation falls on a larger surface, so the intensity decreases. The intensity of solar radiation depends on the mass of air through which the sun's rays pass. The intensity of solar radiation in the mountains will be higher than above sea level, because the layer of air through which the sun's rays pass will be less than above sea level. Special significance represents the influence on the intensity of solar radiation by the state of the atmosphere and its pollution. If the atmosphere is polluted, then the intensity of solar radiation decreases (in the city, the intensity of solar radiation is on average 12% less than in rural areas). The voltage of solar radiation has a daily and annual background, that is, the voltage of solar radiation changes during the day, and also depends on the time of year. The highest intensity of solar radiation is observed in summer, the lowest in winter. In terms of its biological effect, solar radiation is heterogeneous: it turns out that each wavelength has different action on the human body. In this regard, the solar spectrum is conventionally divided into 3 sections:

1. ultraviolet rays, from 280 to 400 nm

2. visible spectrum from 400 to 760 nm

3. infrared rays from 760 to 2800 nm.

With daily and annual solar radiation, the composition and intensity of individual spectra undergo changes. The rays of the UV spectrum undergo the greatest changes.

Visible light.

Biological significance of the visible part of the spectrum. Daylight in middle lane our country in July is about 65,000 lux, and in December - 4,000 lux or less. Air dust levels have a significant impact on the level of daylight. It has been established that in areas with large industry, the intensity of the visible spectrum is 30-40% less compared to areas where the atmospheric air is clean. The visible part of the spectrum is a specific irritant of the organ of vision. Light necessary condition the work of the eye, the most subtle and sensitive sense organ. Light provides approximately 80% of information about the outside world. This is the specific effect of visible light, but also the general biological effect of visible light: it stimulates the body’s vital functions, enhances metabolism, improves overall well-being, affects the psycho-emotional sphere, and increases performance. With a lack of natural light, changes occur in the organ of vision. Fatigue sets in quickly, performance decreases, and work-related injuries increase. The body is affected not only by illumination, but also different colors have different effects on the psycho-emotional state. Yellow-green colors have a calming effect on the body. This is used, for example, in the aesthetic design of pharmacies and chemical and pharmaceutical industry enterprises.

Psychophysiologically, colors act opposite to each other. In this regard, 2 groups of colors were formed:

1) warm colors - yellow, orange, red. 2) cold colors - blue, blue, violet. Cold and warm tones have different physiological effects on the body. Warm tones increase muscle tension, increase blood pressure, and increase the breathing rate. Cold tones, on the contrary, lower blood pressure and slow down the rhythm of the heart and breathing. This is often used in practice: for patients with high temperature Chambers painted purple are most suitable; dark ocher improves the well-being of patients with low blood pressure. Red color increases appetite. Moreover, the effectiveness of drugs can be increased by changing the color of the tablet. Patients suffering from depressive disorders were given the same medicine in tablets different colors: red, yellow, green. The most best results brought treatment with yellow tablets.

Color is used as a carrier of coded information, for example, in production to indicate danger. There is a generally accepted standard for signal identification colors: green - water, red - steam, yellow - gas, orange - acids, purple - alkalis, brown - flammable liquids and oils, blue - air, gray - other.

From a hygienic point of view, the assessment of the visible part of the spectrum is carried out according to the following indicators: natural and artificial lighting are assessed separately. Natural light is assessed according to 2 groups of indicators: physical and lighting. The first group includes:

1. light coefficient - characterizes the ratio of the area of the glazed surface of the windows to the floor area.

2. Angle of incidence - characterizes the angle at which the rays fall. According to the norm, the minimum angle of incidence should be at least 270.

3. Hole angle - characterizes the illumination by heavenly light (must be at least 50). On the first floors of Leningrad houses - wells, this angle is virtually absent.

4. The depth of the room is the ratio of the distance from the top edge of the window to the floor to the depth of the room (the distance from the outer to the inner wall).

Lighting indicators are indicators determined using a device - a lux meter.

For evaluation artificial lighting brightness, lack of pulsation, color, etc. matter in the premises.

Infrared rays.

The main biological effect of these rays is thermal, and this effect also depends on the wavelength. Short rays (760-1500 nm) carry more energy, so they penetrate deeper and have a strong thermal effect. Due to the heating of the meninges of the cerebral cortex, the development of sunstroke is possible. Victims experience severe agitation, loss of consciousness, convulsions and a number of other changes. The adverse effects of infrared rays can lead to diseases such as cataracts (clouding of the lens). Cataracts are caused by short infrared rays.

The long-wavelength region (1500-2500 nm) has its thermal effect on the surface. This is used in physiotherapy to warm up areas at different depths.

In order to measure infrared rays, there is a device - an actinometer. Infrared radiation is measured in calories per cm2min.

Ultraviolet rays (UV).

This is the most biologically active part of the solar spectrum. It is also heterogeneous, A - radiation with wavelengths from 400 to 315 nm and B - radiation with wavelengths from 320 to 280 nm. In this regard, a distinction is made between long-wave and short-wave UV. The biological effect of UV depends only on the quantity and quality of radiant energy absorbed by the clod. It has been established that the stratum corneum of the skin does not transmit rays shorter than 200 nm, and the epidermis with the papillary layer does not transmit rays with a wavelength of less than 313 nm. Therefore, the penetration depth of UV into the skin is about 0.5 nm. When UV enters the skin, 2 groups of substances are formed in it: 1) specific substances, these include vitamin D, 2) non-specific substances - histamine, acetylcholine, adenosine, that is, these are products of protein breakdown.

With insufficient exposure to UV on the human body, various manifestations of D-vitaminosis occur. First of all, the trophism of the central nervous system is disrupted, which leads to weakening redox processes. With vitamin D deficiency, phosphorus-calcium metabolism is disrupted, which is closely related to the processes of skeletal ossification, blood clotting, etc. There is a decline in performance and a decrease in the body's resistance to colds.

The tanning or erythema effect comes down to a photochemical effect - histamine and other biologically active substances promote vasodilation. The peculiarity of this erythema is that it does not appear immediately. Erythema has clearly defined boundaries. Ultraviolet erythema always leads to a more or less pronounced tan, depending on the amount of pigment in the skin. The mechanism of tanning action has not yet been sufficiently studied. In Russia, skin cancer in the southern regions accounts for 20-22% of all forms of cancer, while in the northern regions it does not exceed 7%.

The most favorable tan occurs under the influence of UV light with a wavelength of approximately 320 nm, that is, when exposed to the long-wave part of the UV spectrum. In the south, short-wave UFLs predominate, and in the north, long-wave UFLs predominate. Short-wavelength rays are most susceptible to scattering. And dispersion occurs best in a clean atmosphere and in the northern region. Thus, the most useful tan in the north is longer, darker. UFL are a very powerful factor in the prevention of rickets. With a lack of UVB, rickets develops in children, and osteoporosis or osteomalacia in adults. This is usually encountered in the Far North or among groups of workers working underground. To prevent sunburn, artificial tanning is used. Light starvation is a long-term absence of the UV spectrum. When exposed to UV in the air, ozone is formed, the concentration of which must be controlled.

UV deficiency affects plant photosynthesis processes. In particular, in cereals, this leads to a decrease in protein content and an increase in the amount of carbohydrates in the grains.

UVL provide bactericidal effect. It is used to disinfect large wards, food products, water.

The intensity of UV radiation is determined by the photochemical method by the amount of oxalic acid decomposed under the influence of UV in quartz test tubes (ordinary glass does not transmit UV light). The intensity of UV radiation is also determined by an ultraviolet meter. For medical purposes, ultraviolet radiation is measured in biodoses.

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Solar radiation. Solar radiation is the most important factor for the existence of life on Earth. From a physical point of view solar energy is a stream of electromagnetic radiation with different wavelengths.

The spectral composition of solar radiation varies over a wide range - from long to ultrashort waves.

From a hygienic point of view, the optical part of the solar spectrum is of particular interest, which is divided into three ranges: infrared rays with wavelengths from 28,000 to 760 nm, the visible part of the spectrum - from 760 to 400 nm, and the ultraviolet part - from 400 to 10 nm.

It has been established that solar radiation has a powerful biological effect: it stimulates physiological processes in the body, affects metabolism, general tone, improves a person’s well-being, and increases his performance.

According to their biological activity, infrared harriers are divided into short-wave - with a wave range from 760 to 1400 nm and long-wave - with a wave range from 1,400 to 28,000 nm. Infrared radiation has a thermal effect on the body, which is largely determined by the absorption of the rays by the skin. To treat some inflammatory diseases They use short-wave infrared radiation, which provides warming of deep tissues without the subjective sensation of burning the skin. On the contrary, long-wave infrared radiation is absorbed by the superficial layers of the skin, where thermoreceptors are concentrated, and the burning sensation is pronounced.

The most intense adverse effects of infrared radiation are observed in industrial conditions. In workers in hot shops, glassblowers and representatives of other professions who have contact with powerful streams of infrared radiation, the electrical sensitivity of the eye decreases, the latent period of the visual reaction increases, and the conditioned reflex reaction of the blood vessels is weakened.

Infrared rays are able to pass through the meninges and affect brain receptors. Due to the heating of the meninges of the cerebral cortex, the development of sunstroke is possible. Victims experience severe agitation, loss of consciousness, convulsions and a number of other changes in condition. Under the influence of infrared radiation, damage to the organs of vision in the form of cataracts, changes in the immunological reactivity of the body, etc. is possible.

The intensity of the visible spectrum of solar radiation at the Earth's surface depends on the weather, the height of the Sun above the horizon, dust content in the air and a number of other factors.

Visible light has a general biological effect. This is manifested not only in a specific effect on vision functions, but also in a certain effect on the functional state of the central nervous system and, through it, on all organs and systems. The body reacts not only to this or that illumination, but also to the entire spectrum of sunlight (Table 1).

Optimal conditions for the visual apparatus are created by waves in the green and yellow zones of the spectrum; rays of the orange-red part of the spectrum can cause excitement and increase the feeling of warmth. Blue-violet rays of the solar spectrum have an inhibitory effect that enhances inhibitory processes in the central nervous system.

Table 1. Spectral composition of the visible part of solar radiation

Absorption of ultraviolet radiation by tissue cells leads to the breakdown of protein molecules and nucleic acids. The resulting products (histamine, vitamin D, etc.) are biologically active substances. IN nucleic acids atypical molecular bonds are formed that disrupt the coding properties of DNA.

Aromatic amino acids undergo significant changes: phenylalanine, tyrosine and tryptophan. Cysteine undergoes pronounced destruction. Some cellular enzymes are inactivated.

According to the result final action UV radiation on the body is divided into three regions: UV-C - from 200 to 280 nm. UV-B - from 280 to 315 nm and UV-A - from 315 to 400 nm. UV-B has the greatest biological activity.

The most characteristic reaction of the body to exposure to UV radiation with a wavelength of 315-400 nm is the development of pigmentation, which occurs without prior reddening of the skin. A specific reaction of the body to the action of UV radiation is the development of erythema (redness). Ultraviolet erythema has a number of differences from infrared erythema.

Thus, ultraviolet erythema is characterized by strictly defined contours that limit the areas of exposure to ultraviolet rays; it occurs some time after irradiation and, as a rule, turns into a tan. Infrared erythema occurs immediately after thermal exposure, has blurred edges and does not develop into a tan. Currently, there is evidence indicating a significant role of the central nervous system in the development of ultraviolet erythema. Thus, if the conduction of peripheral nerves is disrupted or after the administration of novocaine, the erythema in this area of the skin is weak or completely absent.

Ultraviolet radiation in the wavelength range from 315 to 280 nm has a specific antirachitic effect, which is manifested in the photochemical reactions of ultraviolet radiation in this range in the synthesis of vitamin D. With insufficient irradiation with ultraviolet rays of the antirachitic spectrum, phosphorus-calcium metabolism suffers. nervous system, parenchymal organs, hematopoietic system, redox processes are reduced, capillary resistance is impaired, performance and resistance to colds are reduced.

In children, rickets occurs with certain clinical symptoms; in adults, phosphorus-calcium metabolism is disrupted due to hypovitaminosis D, which manifests itself in poor healing of bones during fractures, weakening of the ligaments of the joints, and rapid destruction of tooth enamel.

Ultraviolet radiation of the antirachitic spectrum is easily absorbed and scattered in dusty atmospheric air. In this regard, residents of industrial cities, where the atmospheric air is polluted by various emissions, experience “ultraviolet starvation.” Insufficient natural ultraviolet radiation is also experienced by residents of the Far North, workers in the coal and mining industries, people working in dark rooms, etc. To replenish the natural solar radiation of these contingents, people are additionally irradiated with artificial sources of ultraviolet radiation, either in special fotariums, or by combining lighting lamps with lamps that produce radiation in a spectrum close to natural ultraviolet radiation.

The bactericidal effect of UV radiation (rays with wavelengths from 180 to 275 nm) is used in medicine for the sanitation of the air environment of operating rooms, aseptic blocks of pharmacies, microbiological blocks, etc. Germicidal lamps with the above spectrum are used for disinfection of milk, yeast, soft drinks, medicines, etc.

Electrical state of the air. The collective term “atmospheric electricity” usually refers to a whole complex of phenomena, including air ionization, electrical and magnetic fields atmosphere.

Air ionization refers to the disintegration of molecules and atoms with the formation of air ions. As a result, an electron is separated from the molecule and it becomes positively charged, and the detached free electron, joining one of the neutral molecules, imparts a negative charge to it. That is why a pair of oppositely charged particles is formed in the atmosphere - negative and positive ions.

The physical essence of air ionization lies in the action of various ionizing factors on air molecules (radioactive elements, cosmic, ultraviolet radiation, electrical, lightning discharges, balloelectric effect, air ionizers).

Molecular complexes (10-15 molecules) with one elementary charge are called normal, or light, ions. They measure 10-8 cm and have relatively high mobility. Colliding with larger particles that are constantly present in the atmosphere, light ions settle on them and impart their charge to them. Secondary ions appear, including medium (10-6 cm) and heavy (10-5 cm) air ions.

The ionic composition of air is an important hygienic indicator. Moderate increase in the concentration of light ions (especially with a predominance negative sign) can be seen as a positive phenomenon. Human exposure to light negative air ions is characterized by a beneficial biological effect. On the contrary, excessively high concentrations of positive ions, especially heavy ones, indicate low hygienic air quality.

The ratio of the number of heavy ions to the number of light ions determines the ionization regime of the air. To characterize the ionization of air, the unipolarity coefficient is used, showing the ratio of the number of positive ions to the number of negative ions. The more the air is polluted, the higher this coefficient.

The amount of light ions depends on geographical, geological conditions, weather, the level of environmental radioactivity, and air pollution. As air humidity increases, the amount of heavy ions increases due to the recombination of ions with moisture droplets. Demotion atmospheric pressure promotes the release of radium emanation from the soil, which leads to an increase in the amount of light ions. The ionizing effect of sprayed water is manifested in increased ionization of the air, which is especially noticeable near fountains, along the banks of stormy rivers, and near reservoirs.

V.I. Arkhangelsky, V.F. Kirillov

General hygiene. Solar radiation and its hygienic significance.

By solar radiation we mean the entire flux of radiation emitted by the Sun, which is electromagnetic oscillations of various wavelengths. From a hygienic point of view, the optical part of sunlight, which occupies the range from 280-2800 nm, is of particular interest. Longer waves are radio waves, shorter ones are gamma rays, ionizing radiation does not reach the Earth's surface because it is delayed in upper layers atmosphere, in the ozone layer in particular. Ozone is distributed throughout the atmosphere, but at an altitude of about 35 km it forms the ozone layer.

The intensity of solar radiation depends primarily on the height of the sun above the horizon. If the sun is at its zenith, then the path taken by the sun's rays will be much shorter than their path if the sun is at the horizon. By increasing the path, the intensity of solar radiation changes. The intensity of solar radiation also depends on the angle at which the sun's rays fall, and the illuminated area also depends on this (as the angle of incidence increases, the area of illumination increases). Thus, the same solar radiation falls on a larger surface, so the intensity decreases. The intensity of solar radiation depends on the mass of air through which the sun's rays pass. The intensity of solar radiation in the mountains will be higher than above sea level, because the layer of air through which the sun's rays pass will be less than above sea level. Of particular importance is the influence on the intensity of solar radiation by the state of the atmosphere and its pollution. If the atmosphere is polluted, then the intensity of solar radiation decreases (in the city, the intensity of solar radiation is on average 12% less than in rural areas). The voltage of solar radiation has a daily and annual background, that is, the voltage of solar radiation changes throughout the day, and also depends on the time of year. The highest intensity of solar radiation is observed in summer, the lowest in winter. In terms of its biological effect, solar radiation is heterogeneous: it turns out that each wavelength has a different effect on the human body. In this regard, the solar spectrum is conventionally divided into 3 sections:

ultraviolet rays, from 280 to 400 nm

visible spectrum from 400 to 760 nm

infrared rays from 760 to 2800 nm.

With daily and annual solar radiation, the composition and intensity of individual spectra undergo changes. The rays of the UV spectrum undergo the greatest changes.

We estimate the intensity of solar radiation based on the so-called solar constant. The solar constant is the amount of solar energy received per unit time per unit area located at the upper boundary of the atmosphere at right angles to sun rays at the average distance of the Earth from the Sun. This solar constant was measured by satellite and is equal to 1.94 calories/cm 2 per minute. Passing through the atmosphere, the sun's rays are significantly weakened - scattered, reflected, absorbed. On average, with a clean atmosphere on the Earth's surface, the intensity of solar radiation is 1.43 - 1.53 calories/cm 2 per minute.

The intensity of solar rays at noon in May in Yalta is 1.33, in Moscow 1.28, in Irkutsk 1.30, in Tashkent 1.34.

Biological significance of the visible part of the spectrum.

The visible part of the spectrum is a specific irritant of the organ of vision. Light is a necessary condition for the functioning of the eye, the most subtle and sensitive sense organ. Light provides approximately 80% of information about the outside world. This is the specific effect of visible light, but also the general biological effect of visible light: it stimulates the vital activity of the body, enhances metabolism, improves overall well-being, affects the psycho-emotional sphere, and increases performance. Light makes you healthier environment. With a lack of natural light, changes occur in the organ of vision. Fatigue sets in quickly, performance decreases, and work-related injuries increase. The body is affected not only by illumination, but also different colors have different effects on the psycho-emotional state. The best performance indicators were obtained with the preparation under yellow and white lighting. Psychophysiologically, colors act opposite to each other. In this regard, 2 groups of colors were formed: 1) warm colors - yellow, orange, red. 2) cold tones - blue, blue, violet. Cold and warm tones have different physiological effects on the body. Warm tones increase muscle tension, increase blood pressure, and increase the breathing rate. Cold tones, on the contrary, lower blood pressure and slow down the rhythm of the heart and breathing. This is often used in practice: for patients with high temperatures, wards painted purple are most suitable; dark ocher improves the well-being of patients with low blood pressure. Red color increases appetite. Moreover, the effectiveness of the drug can be increased by changing the color of the tablet. Patients suffering from depressive disorders were given the same medicine in tablets of different colors: red, yellow, green. Treatment with yellow tablets brought the best results.

Color is used as a carrier of coded information, for example in production to indicate danger. There is a generally accepted standard for signal identification colors: green - water, red - steam, yellow - gas, orange - acids, purple - alkalis, brown - flammable liquids and oils, blue - air, gray - other.

From a hygienic point of view, the assessment of the visible part of the spectrum is carried out according to the following indicators: natural and artificial lighting are assessed separately. Natural lighting is assessed according to 2 groups of indicators: physical and lighting. The first group includes:

luminous coefficient - characterizes the ratio of the area of the glazed surface of windows to the floor area.

Angle of incidence - characterizes the angle at which the rays fall. According to the norm, the minimum angle of incidence should be at least 27 0.

The angle of the hole characterizes the illumination by heavenly light (must be at least 5 0). On the first floors of Leningrad houses - wells, this angle is virtually absent.

The depth of a room is the ratio of the distance from the top edge of the window to the floor to the depth of the room (the distance from the outer to the inner wall).

Lighting indicators- these are indicators determined using a device - a lux meter. Absolute and relative illumination is measured. Absolute illumination is the illumination on the street. Illuminance coefficient (KEO) is defined as the ratio of relative illuminance (measured as the ratio of relative illuminance (measured in a room) to absolute, expressed in %. Illumination in a room is measured at the workplace. The principle of operation of a lux meter is that the device has a sensitive photocell (selenium - since selenium is close in sensitivity to the human eye). The approximate illumination on the street can be determined using a light climate graph.

To evaluate artificial lighting of premises, brightness, lack of pulsation, color, etc. are important.

INFRARED RAYS. The main biological effect of these rays is thermal, and this effect also depends on the wavelength. Short rays carry more energy, so they penetrate deeper and have a strong thermal effect. The long-length section exerts its thermal effect on the surface. This is used in physiotherapy to warm up areas at different depths.

In order to measure infrared rays, there is a device - an actinometer. Infrared radiation is measured in calories per cm2\min. The adverse effects of infrared rays are observed in hot shops, where they can lead to occupational diseases - cataracts (clouding of the lens). Cataracts are caused by short infrared rays. A preventative measure is the use of protective glasses and protective clothing.

Features of the impact of infrared rays on the skin: burns occur - erythema. It occurs due to thermal expansion of blood vessels. Its peculiarity is that it has different boundaries and appears immediately.

Due to the action of infrared rays, 2 conditions of the body can occur: heatstroke and sunstroke. Sunstroke is the result of direct exposure to sunlight on the human body, mainly with damage to the central nervous system. Sunstroke affects those who spend many hours in a row under the scorching rays of the sun with their heads uncovered. The meninges are warmed up.

Heat stroke occurs due to overheating of the body. It can happen to those who perform heavy physical work in a hot room or in hot weather. Heat strokes were especially common among our military personnel in Afghanistan.

In addition to actinometers for measuring infrared radiation, there are various types of pyramidometers. The basis of this action is the absorption of radiant energy by the black body. The receptive layer consists of blackened and white plates, which, depending on infrared radiation, heat up differently. A current is generated on the thermopile and the intensity of infrared radiation is recorded. Since the intensity of infrared radiation is important in production conditions, there are standards for infrared radiation for hot shops in order to avoid adverse effects on the human body, for example, in a pipe-rolling shop the bench is 1.26 - 7.56, iron smelting 12.25. Radiation levels exceeding 3.7 are considered significant and require preventive measures - the use of protective screens, water curtains, and special clothing.

ULTRAVIOLET RAYS (UV).

This is the most biologically active part of the solar spectrum. It is also heterogeneous. In this regard, a distinction is made between long-wave and short-wave UV. UV promotes tanning. When UV enters the skin, 2 groups of substances are formed in it: 1) specific substances, these include vitamin D, 2) non-specific substances - histamine, acetylcholine, adenosine, that is, these are products of protein breakdown. The tanning or erythema effect comes down to a photochemical effect - histamine and other biologically active substances promote vasodilation. The peculiarity of this erythema is that it does not appear immediately. Erythema has clearly defined boundaries. Ultraviolet erythema always leads to a more or less pronounced tan, depending on the amount of pigment in the skin. The mechanism of tanning action has not yet been sufficiently studied. It is believed that first erythema occurs, nonspecific substances such as histamine are released, the body converts the products of tissue breakdown into melanin, as a result of which the skin acquires a peculiar shade. Tanning, therefore, is a test of the body's protective properties (a sick person does not tan, tans slowly).

The most favorable tanning occurs under the influence of UV rays with a wavelength of approximately 320 nm, that is, when exposed to the long-wavelength part of the UV spectrum. In the south, short-wave UFLs predominate, and in the north, long-wave UFLs predominate. Short-wavelength rays are most susceptible to scattering. And dispersion occurs best in a clean atmosphere and in the northern region. Thus, the most useful tan in the north is longer, darker. UFL are a very powerful factor in the prevention of rickets. With a lack of UVB, rickets develops in children, and osteoporosis or osteomalacia in adults. This is usually encountered in the Far North or among groups of workers working underground. In the Leningrad region, from mid-November to mid-February, the UV part of the spectrum is practically absent, which contributes to the development of solar starvation. To prevent sunburn, artificial tanning is used. Light starvation is a long-term absence of the UV spectrum. When exposed to UV in the air, ozone is formed, the concentration of which must be controlled.

UV rays have a bactericidal effect. It is used to disinfect large wards, food products, and water.

Take into account and evaluate the results of sowing the enrichment culture on bismuth-sulfite agar (BCA).

Methodological instructions for completing the research task:

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