Daily Quiz: UPSC Prelims Marathon – December 7

X Rays – X-rays were discovered by William Roentgen. He produced these rays by bombarding electron to an element having high atomic number say Tungsten or Copper. X-rays can carry enough energy to ionize atoms and disrupt molecular bonds.

Radiography is the use of X-rays to view a non-uniformly composed material such as the human body. By using the physical properties of the ray an image can be developed which displays areas of different density and composition.

The human skin is composed of a minimum of 3 major layers of tissue:

• Epidermis: Thin, tough, outer layer made up of epithelial cells & it does not contain blood vessels.
• Stratum corneum is the outermost portion of the epidermis, prevents most bacteria, viruses, and other foreign substances from entering the body
• Melanocytes produce the pigment melanin, function is to filter out ultraviolet radiation from sunlight
• Langerhans cells are part of the skin’s immune system which helps detect foreign substances and defend the body against infection.
• Dermis: Thick layer of fibrous and elastic that gives the skin its flexibility and strength. Contains nerve endings, sweat glands and oil (sebaceous) glands, hair follicles, and blood vessels
• Sweat glands produce sweat in response to heat and stress.  The sebaceous glands secrete sebum into hair follicles. Sebum is oil that keeps the skin moist and soft and acts as a barrier against foreign substances.
• The blood vessels of the dermis provide nutrients to the skin and help regulate body temperature.
• Hypodermis: Its purpose is to attach the skin to underlying bone and muscle as well as supplying it with blood vessels and nerves

• Arthritis: Inflammation of joints.
• Osteoporosis: Age-related disorder characterized by decreased bone mass and increased chances of fractures. Decreased levels of estrogen is a common cause.
• Gout: Inflammation of joints due to accumulation of uric acid crystals.

The Australian Group :

• The Australia Group is an informal group to help member countries identify those exports which need to be controlled so as not to contribute to the spread of chemical and biological weapons.
• It has 42 members including the European Commission, all 28 member states of the European Union, Ukraine, and Argentina.
• Members of the group maintain export controls on a uniform list of 54 compounds, including several that are not prohibited for export under the Chemical Weapons Convention, but can be used in the manufacture of chemical weapons.
• The group follows two policies- ―no undercut and ―catch all.
• The “no-undercut” requirement, states that any member of the group considering making an export to another state that had already been denied an export by any other member of the group must first consult with that member state before approving the export.
• “Catch-all” provision, which requires member states to halt all exports that could be used by importers in chemical or biological weapons programs, regardless of whether the export is on the group’s control lis

Members meet every year in Paris.

Application of Liquid Nitrogen:

• Cryotherapy for removing unsightly or potentially malignant skin lesions such as warts and actinic keratosis
• To store cell at low temperature for laboratory work
• for the immersion, freezing, and transportation of food products
• for the cryopreservatiom of blood, reproductive cells (Sperm and Egg
• To facilitate cryoconservation of animal genetic resources
• To freeze water and oil pipes in order to work on them in situations where a valve is not available to block fluid flow to the work area; this method is known as a cryogenic isolation
• In the process of  promession, a way to dispose of the dead
• To shrink-weld machinery parts together
• as a coolant
• for CCD cameras in astronomy
• For a high-temperature superconductor to a temperature sufficient to achieve superconductivity
• In food preparation, such as for making ultra-smooth ice cream

Important Learning:

Nitrogen has a large expansion ratio. When it evaporates the liquid freezes everything around it and causes oxygen deficiency. The expansion can cause stomach to burst

Defence Research and Development Organisation (DRDO) has developed India’s first unmanned tank, which has three variants – surveillance, mine detection and reconnaissance in areas with nuclear and bio threats. It is called Muntra (Mission UNmanned TRAcked)

The tanks will facilitate Indian Armed forces in conducting unmanned surveillance missions. Muntra-S has been developed for unmanned surveillance missions, whereas Muntra-M is built for detecting mines. Muntra-N will be deployed in areas where nuclear radiation or bio weapon risk is high

A concept introduced by the United Nation’s programme on HIV/AIDS in 2013, 90-90-90 is a set of goals. The idea is that by 2020, 90% of people who are HIV infected will be diagnosed, 90% of people who are diagnosed will be on antiretroviral treatment and 90% of those who receive antiretrovirals will be virally suppressed. Viral suppression  is when a person’s viral load – or the amount of virus in an HIV-positive person’s blood – is reduced to an undetectable level.