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How solar cells can play as an energy source?

You must have learnt quite a bit about solar panels in school. An electrical device that converts the energy of light directly into electricity, solar cells or photovoltaic cells tap solar energy. As the energy is produced from a renewable source, our sun, they offer huge potential in helping us move away from energy generated by burning fossil fuels (non-renewable sources)

Given the important role solar cells can play as an energy source, there is plenty of research on to figure out if we can make the process more efficient. Among these are research that aim at increasing the light captured, as it directly influences the energy produced

Design innovation

An innovation suggested by a team of scientists late in 2020 stands to more than double the light that can be captured by solar cells when compared to conventional solar cells. The team, comprising scientists from the U.K., Portugal and Brazil, discovered that etching a simple pattern could lead to this considerable gain.

According to their study, a shallow pattern of grating lines in a chequerboard design on solar cells can increase the current generated by as much as 125%.

Chequerboard pattern

In their attempt to try and trap more sunlight, the researchers experimented with this design along with other designs (vertical grating lines, crossed lines, etc.) and a conventional plain solar cell. Results showed that the chequerboard pattern with random rotations of the repeating units far outperformed the other competing cells and the conventionally used plain one as well.

While the results might not be as impressive when implemented in the real world with the fabrication measures, the change could well lead to positive impact in the design of new solar cells as a whole. Only time and more experiments can tell us if the chequerboard design does yield the results that we yearn for.

 

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How many sweat glands are there in the human body?

Humans have 2,000,000 to 5,000,000 eccrine sweat glands, with an average distribution of 150 to 340 per square centimetre. They are most numerous on the palms and soles and then, in decreasing order, on the head, trunk, and extremities. Some individuals have more glands than others, but there is no difference in number between men and women.

The specific function of sweat glands is to secrete water upon the surface so that it can cool the skin when it evaporates. The purpose of the glands on the palms and soles, however, is to keep these surfaces damp, to prevent flaking or hardening of the horny layer, and thus to maintain tactile sensibility. A dry hand does not grip well and is minimally sensitive.

The glands on the palms and soles develop at about 3 1/2 months of gestation, whereas those in the hairy skin are the last skin organs to take shape, appearing at five to 5 1/2 months, when all the other structures are already formed. This separation of events over time may represent a fundamental difference in the evolutionary history of the two types of glands. Those on palms and soles, which appear first and are present in all but the hooved mammals, may be more ancient; those in the hairy skin, which respond to thermal stimuli, may be more recent organs.

 

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What is gustatory sweating?

Gustatory sweating is sweating that occurs on the forehead, scalp, neck, and upper lip while eating, talking, or thinking about food.

Gustatory sweating can occur for no apparent reason or as a result of an underlying condition, such as diabetes or Parkinson’s disease. These diseases can also cause damage to the nerves in the mouth. When the nerves become injured, they can become confused and cause sweating.

Gustatory sweating may cause some people distress, as thinking about food can trigger the reactions of sweating. Since there is often an underlying cause, a person should talk to their doctor to find out what may be causing the sweating.

People do not necessarily need to see a doctor after sweating from eating food. Those who only sweat while eating either very hot or spicy foods have no reason to be concerned.

Some people who experience Frey’s syndrome may consider it to be a nuisance but do not consider it significant enough to seek help.

 

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Sweat is made of 99% water. What is the remaining 1%?

A body has between two and four million sweat glands lying deep in the skin. They are connected to the surface by coiled tubes called ducts. You perspire constantly, even without exercise. Sweat is a liquid made from 99% water and 1% salt and fat. Up to a quart of sweat evaporates each day.

When your body becomes overheated, you sweat more. The evaporation of sweat from your skin cools your body down.

When you’re frightened or nervous (imagine being pinned under heavy weights) you also sweat more. Your palms and forehead begin to sweat. So do the soles of your feet and your armpits. These are sites where sweat glands are most abundant.

So why do you smell when you sweat? You may notice the smell mostly comes from our pits (hence why we put deodorant there). This is because the apocrine glands produce the bacteria that break down our sweat into “scented” fatty acids.

“Apocrine sweat by itself does not have an odor, but when the bacteria that lives on our skin mixes with apocrine secretions, it can produce a foul-smelling odor,” Haimovic says.

 

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What is perspiration?

Perspiration, also known as sweating, is the production of fluids secreted by the sweat glands in the skin of mammals.

Two types of sweat glands can be found in humans: eccrine glands and apocrine glands. The eccrine sweat glands are distributed over much of the body and are responsible for secreting the watery, brackish sweat most often triggered by excessive body temperature. The apocrine sweat glands are restricted to the armpits and a few other areas of the body and produce an odorless, oily, opaque secretion which then gains its characteristic odor from bacterial decomposition.

Sweat contributes to body odor when it is metabolized by bacteria on the skin. Medications that are used for other treatments and diet also affect odor. Some medical conditions, such as kidney failure and diabetic ketoacidosis, can also affect sweat odor. Areas that produce excessive sweat usually appear pink or white, but, in severe cases, may appear cracked, scaly, and soft.

 

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What disease in children do Rotavirus vaccines address?

Rotavirus spreads easily among infants and young children. The virus can cause severe watery diarrhea, vomiting, fever, and abdominal pain. Children who get rotavirus disease can become dehydrated and may need to be hospitalized.

Good hygiene like handwashing and cleanliness are important, but are not enough to control the spread of the disease. Rotavirus vaccine is the best way to protect your child against rotavirus disease. Most children (about 9 out of 10) who get the vaccine will be protected from severe rotavirus disease. About 7 out of 10 children will be protected from rotavirus disease of any severity.

Treatment will depend on your child’s symptoms, age, and general health. It will also depend on how severe the condition is. Antibiotics are not used to treat this illness. Medicines for diarrhea are also not recommended. Some healthcare providers may recommend probiotics. But their effectiveness is unclear.

The goal of treatment is to help reduce symptoms. Treatment may include:

  • Giving your child plenty of water, formula, breastmilk, or fluids with electrolytes (sugars and salts). Don’t give young children soda, juice, or sports drinks.
  • Feeding your child solid foods if he or she can eat. Don’t restrict food if your child is able to eat. Not having food may cause the diarrhea to last longer.

If your child loses too much water, he or she may need to be in the hospital. Treatment there may include:

  • Intravenous (IV) fluids.  A thin, flexible tube is put into your child’s vein. Fluids are given through this tube.
  • Blood tests. These are done to measure the levels of sugar, salt, and other chemicals (electrolytes) in your child’s blood.

 

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Which was the first disease against which vaccination was developed?

The story of vaccines did not begin with the first vaccine–Edward Jenner’s use of material from cowpox pustules to provide protection against smallpox. Rather, it begins with the long history of infectious disease in humans, and in particular, with early uses of smallpox material to provide immunity to that disease.

Evidence exists that the Chinese employed smallpox inoculation (or variolation, as such use of smallpox material was called) as early as 1000 CE. It was practiced in Africa and Turkey as well, before it spread to Europe and the Americas.

Edward Jenner’s innovations, begun with his successful 1796 use of cowpox material to create immunity to smallpox, quickly made the practice widespread. His method underwent medical and technological changes over the next 200 years, and eventually resulted in the eradication of smallpox.

Louis Pasteur’s 1885 rabies vaccine was the next to make an impact on human disease. And then, at the dawn of bacteriology, developments rapidly followed. Antitoxins and vaccines against diphtheria, tetanus, anthrax, cholera, plague, typhoid, tuberculosis, and more were developed through the 1930s.

The middle of the 20th century was an active time for vaccine research and development. Methods for growing viruses in the laboratory led to rapid discoveries and innovations, including the creation of vaccines for polio. Researchers targeted other common childhood diseases such as measles, mumps, and rubella, and vaccines for these diseases reduced the disease burden greatly.

Innovative techniques now drive vaccine research, with recombinant DNA technology and new delivery techniques leading scientists in new directions. Disease targets have expanded, and some vaccine research is beginning to focus on non-infectious conditions such as addiction and allergies.

 

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Who is known as the father of vaccinology?

Edward Jenner was an English physician and scientist who pioneered the concept of vaccines including creating the smallpox vaccine, the world’s first vaccine. The terms vaccine and vaccination are derived from Variolae vaccinae (smallpox of the cow), the term devised by Jenner to denote cowpox. He used it in 1798 in the long title of his Inquiry into the Variolae vaccinae known as the Cow Pox, in which he described the protective effect of cowpox against smallpox.

He still remembered the Bristol milkmaid’s remark and acquired the reputation of a bore because of his constant harping on cowpox and its preventive use. Eventually, and totally unethically, he took lymph from a pustule on the hand of a milkmaid and inoculated a healthy child, who developed cowpox in the normal fashion but proved immune to subsequent inoculation with smallpox. Both the medical profession and the Royal Society were hostile to these unorthodox practices so Jenner published his observations in 1798 and travelled to London to publicize them. His reception was so unenthusiastic that he returned to Gloucestershire leaving some lymph with Mr Cline, a surgeon at St Thomas’s Hospital. Cline used it to inoculate a child who also proved immune to a later attempt at smallpox inoculation and this popularized the practice.

 

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Which part of a girl’s body produces and releases eggs at the mid-point of each menstrual cycle?

The ovaries form part of the female reproductive system. Each woman has two ovaries. They are oval in shape, about four centimetres long and lie on either side of the womb (uterus) against the wall of the pelvis in a region known as the ovarian fossa. They are held in place by ligaments attached to the womb but are not directly attached to the rest of the female reproductive tract, e.g. the fallopian tubes.  

The major hormones secreted by the ovaries are oestrogen and progesterone, both important hormones in the menstrual cycle. Oestrogen production dominates in the first half of the menstrual cycle before ovulation, and progesterone production dominates during the second half of the menstrual cycle when the corpus luteum has formed. Both hormones are important in preparing the lining of the womb for pregnancy and the implantation of a fertilised egg, or embryo.

If conception occurs during any one menstrual cycle, the corpus luteum does not lose its ability to function and continues to secrete oestrogen and progesterone, allowing the embryo to implant in the lining of the womb and form a placenta. At this point, development of the foetus begins. 

 

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Which are group hormones that primarily influence the growth and development of the male reproductive system?

Androgen, any of a group of hormones that primarily influence the growth and development of the male reproductive system. The predominant and most active androgen is testosterone, which is produced by the male testes.

In males the interstitial cells of Leydig, located in the connective tissue surrounding the sperm-producing tubules of the testes, are responsible for the production and secretion of testosterone. In male animals that breed only seasonally, such as migratory birds and sheep, Leydig cells are prevalent in the testes during the breeding season but diminish considerably in number during the nonbreeding season. The actual secretion of androgens by these cells is controlled by luteinizing hormone (LH) from the pituitary gland.

The adrenal production of androgens is of importance to several physiological processes. Certain adrenal androgens—androstenedione, dehydroepiandrosterone (DHEA), and dehydroepiandrosterone sulfate (DHEA sulfate)—can be converted to testosterone in other tissues.

 

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