What is a virus? Detailed answer

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What is a virus? Detailed answer

Big encyclopedia for children and adults

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What is a virus?

Viruses are tiny particles that cause various diseases in humans, animals and plants. The word "particles" may seem strange, but let's see why we use it. Viruses are so small that they can seep through even the finest filters. Their tiny size does not allow them to be seen with a conventional microscope, so when studying viruses, scientists are forced to use photographs taken with an electron microscope.

Unlike bacteria, they cannot be bred in sugar syrup: they grow and multiply only in the presence of living matter. Being parasites, they are entirely dependent on the organism in which they are located. Due to the fact that they are so small and it is extremely difficult to artificially create conditions for their growth, many researchers are inclined to think that viruses are not living organisms at all, but some kind of middle link between living and inanimate matter.

Viruses are sources of disease, many of which are known to all. By affecting different organs of the body, each group of viruses causes different types of diseases.

Many skin diseases, such as chickenpox, smallpox, measles, are the result of the activity of one group of viruses. Another is the cause of diseases of the central nervous system: rabies, inflammation of the brain, infantile paralysis. The third affects the internal organs and causes yellow fever, influenza, the common cold, viral inflammation of the liver, and many others.

Author: Likum A.

Random interesting fact from the Great Encyclopedia:

What are moles?

The name mole or birthmarks refers to those marks on the body that appear from birth. Medicine does not yet know the causes of their occurrence, and ways to prevent their occurrence have not yet been developed. But one thing is certain: they have nothing to do with any fears experienced by the mother of the child before his birth.

Almost everyone has at least one mole somewhere on the body. They can appear anywhere, including on the scalp. Moles can vary greatly in appearance, depending on which layer of the skin they appear in. Most birthmarks appear before birth or immediately after, but in some cases they do not appear until fourteen or fifteen years of age. If they are not touched, then moles cannot bring any harm to the body.

The biggest danger associated with them is that if they are damaged, they can transform into a malignant tumor. But this happens very rarely, and most people who have moles have nothing to worry about.

There are a number of other skin abnormalities that can be mistaken for moles. One of them is reddish or purple formations that appear on the skin at birth or shortly after birth. Sometimes they have a strawberry or raspberry hue. This is actually an unusual condition of the blood vessels, and usually these formations disappear after treatment. But many doctors believe they should be removed as soon as possible to avoid scarring.

Doctors even consider freckles to be a "lack of skin." Freckles appear due to exposure to ultraviolet rays of sunlight. Most often, freckles appear in fair-haired people with white skin.

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Latest news of science and technology, new electronics:

Machine for thinning flowers in gardens 02.05.2024

In modern agriculture, technological progress is developing aimed at increasing the efficiency of plant care processes. The innovative Florix flower thinning machine was presented in Italy, designed to optimize the harvesting stage. This tool is equipped with mobile arms, allowing it to be easily adapted to the needs of the garden. The operator can adjust the speed of the thin wires by controlling them from the tractor cab using a joystick. This approach significantly increases the efficiency of the flower thinning process, providing the possibility of individual adjustment to the specific conditions of the garden, as well as the variety and type of fruit grown in it. After testing the Florix machine for two years on various types of fruit, the results were very encouraging. Farmers such as Filiberto Montanari, who has used a Florix machine for several years, have reported a significant reduction in the time and labor required to thin flowers. ... >>

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Random news from the Archive

Compact medical power supplies Mean Well RPS-400 03.03.2017

Mean Well has developed a series of small size 400W power supplies (with external fan) for medical applications. The new RPS-400 series has a footprint of only 3"x5" and is available in the following modifications: open, in a casing (at the end of the name -C symbol), with a fan installed on top (-TF) and with a fan installed on the side of the output connector (-SF).

At the moment, among the power supplies of the RPS family, you can optimally select the required unit in a wide power range from 30 to 400 W (RPS-30/45/60/65/75/120/160/200/300/400). The new power supplies meet medical standards IEC60601-1 (Version 3), ANSI/AAMI ES60601-1 and TUV EN60601-1; have a protection level of 2 x MOPP, low leakage current (less than 250 µA) and can be used in devices that come into contact with the patient's body.

The RPS-400 features low standby power consumption (less than 0,5W), high efficiency (96% efficiency typ.); there is a power correction stage. The power supplies meet the EMC requirements of class B when connected with earth and class A when connected without earth.

Main Technical Parameters of RPS-400 Series

Output power 400 W (with blower); 250 W (no fan)
Output voltage from a row: 12; fifteen; eighteen; 15; 18; 24; 27 V
Input voltage range 80-264V (AC) / 113-370 (DC)
Efficiency 93% (typ.)
KM>0,94
Insulation voltage input-output 4 kV
Leakage current <250uA
Temperature range -30°С...+70°С (with dependence)
Low standby consumption <0,5W
Optional 12V/0,5A output (for fan)
Standby 5V/1A
3 years warranty

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