"Five Elements of the Periodic Table (2)"

Continuation of the descriptions of Five Elements of the Periodic Table:

4. Cesium 

Discoverer: Gustov Kirchoff, Robert Bunsen 

Discovery Date and Location: 1860 (Germany) 

Uses: Cesium is used in atomic clocks, which are incredibly accurate. NIST-F1, America’s primary time and frequency standard, is a cesium fountain atomic clock developed at the NIST laboratories in Boulder, Colorado. NIST-F1 contributes to the international group of atomic clocks that define Coordinated Universal Time (UTC), the official world time. As scientists continue to improve its technology, uncertainty in NIST-F1′s measurement of time is continually improving. Currently it neither gains nor loses as much a second in more than 60 million years – but see strontium.
Cesium is also used in photoelectric cells and as a catalyst in the hydrogenation of organic compounds. The metal is used as a ‘getter’ in vacuum tubes.
Cesium hydroxide is used to etch silicon. 

5. Krypton 

Discovery: Sir William Ramsey, M.W. Travers, 1898 (Great Britain) 
 
Uses:
Krypton based bulbs are used in some photography applications because it produces white light under certain conditions. It is usually used in high speed flash photography.

This white discharge is also used in colored gas tubes to create a similar effect to a neon sign.

Krypton is used in the production and usage of the krypton fluoride laser, which is being used in research for nuclear fusion. It is also suitable for use in high powered laser shows.

It is mixed with argon to fill fluorescent lamps. This makes them more energy efficient by reducing the power they require. Unfortunately, this also makes this type of bulb more expensive and reduces the light output. It is also, together with xenon, used in regular light bulbs to reduce filament evaporation and allow it to operate at higher temperatures.

An isotope of krypton is used in medical scans (MRI scan) of the airways.

A measure of the wavelength of light emitted isotope of krypton was used to define the distance of a meter from 1960 to 1983. 

Uses: Cesium is used in atomic clocks, which are incredibly accurate. NIST-F1, America’s primary time and frequency standard, is a cesium fountain atomic clock developed at the NIST laboratories in Boulder, Colorado. NIST-F1 contributes to the international group of atomic clocks that define Coordinated Universal Time (UTC), the official world time. As scientists continue to improve its technology, uncertainty in NIST-F1′s measurement of time is continually improving. Currently it neither gains nor loses as much a second in more than 60 million years – but see strontium.
Cesium is also used in photoelectric cells and as a catalyst in the hydrogenation of organic compounds. The metal is used as a ‘getter’ in vacuum tubes.
Cesium hydroxide is used to etch silicon. 

SOURCES:

http://wanttoknowit.com/uses-of-krypton/ 

http://chemistry.about.com/od/elementfacts/a/cesium.htm

http://www.chemicool.com/elements/cesium.html  

 

"Five Elements of the Periodic Table (1)"

1. Beryllium

Beryllium was discovered by Louis-Nicholas Vanquelin during 1798, in France.

Uses: Precious forms of beryl include aquamarine, morganite, and emerald. Beryllium is used as an alloying agent in producing beryllium copper, which is used for springs, electrical contacts, non sparkling tools, and spot-wedding electrodes. It is used in many structural components of the space shuttle and other aerospace craft. Beryllium foil is used in x-ray lithography for making integrated circuits. It is used as a reflector or moderatior in nuclear reactions. Beryllium is used in gyroscopes and computer parts.

2. Lithium

Discovery: 1817, Arfvedson (Sweden)

Uses: Lithium is used in heat transfer applications. It is used as an alloying agent, in synthesizing organic compounds, and is added to glasses and ceramics. Its high electrochemical potential makes it useful for battery anodes. Lithium chloride and lithium bromide are highly hygroscopic, so are used as drying agents. Lithium stearate is used as a high-temperature lubricant. Lithium has medical applications, as well.

Lithium is used extensively in rechargeable battery technology.

Lithium is the only alkali metal that reacts with nitrogen.

Lithium burns red in a flame test.

Lithium was first discovered in the mineral petalite (LiAlSi₄O₁₀).

Lithium is used to create the hydrogen isotope tritium through bombardment of neutrons.

3. Helium

Helium Discovery: Janssen, 1868, some sources say Sir William Ramsey, Nils Langet, P.T. Cleve 1895

Uses: Helium is widely used in cryogenic research because its boiling point is near absolute zero. It is used in the study of superconductivity, as an inert gas shield for arc welding, as a protective gas in growing silicon and germanium crystals and producing titanium and zirconium, for pressuring liquid fuel rockets, for use in magnetic resonance imaging (MRI), as a cooling medium for nuclear reactors, and as a gas for supersonic wind tunnels. A mixture of helium and oxygen is used as an artificial atmosphere for divers and others working under pressure. Helium is used for filling balloons and blimps.

SOURCES: 

http://chemistry.about.com/od/elementfacts/a/beryllium.htm

http://chemistry.about.com/od/elementfacts/a/lithium.htm 

http://chemistry.about.com/od/elementfacts/a/helium.htm 

"Reproductive Technology"

               In Vitro Fertilization is another common fertility treatment. Eggs and sperm are taken from the couple (or a donor) and combined in a laboratory. The eggs are removed with a needle while the woman is under local anesthesia. If an embryo forms in the lab, it is placed in the woman’s uterus a few days later. The embryo transfer is done through the cervix. Like many other types of fertility treatments, multiple embryos are usually implanted. This is done because the procedures are very expensive, and multiple embryos offer a higher chance of having a successful pregnancy.


Step 1: Stimulation, also called super ovulation
Medicines, commonly called fertility drugs, are given to the woman to boost her egg production. Normally, a woman produces one egg per month. Fertility drugs tell the ovaries to produce several eggs. During this step, the woman will have regular transvaginal ultrasounds to examine the ovaries and blood tests to check hormone levels.

Step 2: Egg retrieval
A minor surgery, called follicular aspiration, is done to remove the eggs from the woman’s body. The surgery is normally done as an outpatient procedure in the doctor’s office. The woman will be given medicines so she does not feel pain during the procedure. Using ultrasound images as a guide, the health care provider inserts a thin needle through the vagina and into the ovary and sacs (follicles) containing the eggs. The needle is connected to a suction device, which pulls the eggs and fluid out of each follicle, one at a time. The procedure is repeated for the other ovary. The woman may have some cramping after the surgery, but it usually goes away within a day. In rare cases, a pelvic laparoscopy may be needed to remove the eggs.
If a woman does not or cannot produce any eggs, donated eggs may be used.

Step 3: Insemination and Fertilization
The man’s sperm is placed together with the best quality eggs and stored in an environmentally controlled chamber. The mixing of the sperm and egg is called insemination. The sperm usually enters (fertilizes) an egg a few hours after insemination. If the doctor thinks the chance of fertilization is low, the laboratory staff may directly inject the sperm into the egg. This is called intracytoplasmic sperm injection (ICSI). Many fertility programs routinely do ICSI on some of the eggs even if everything is normal.

Step 4: Embryo culture
When the fertilized egg divides, it becomes an embryo. Laboratory staff will regularly check the embryo to make sure it is growing properly. Within about 5 days, a normal embryo has several cells that are actively dividing.
Couples who have a high risk of passing a genetic (hereditary) disorder to a child may consider pre-implantation genetic diagnosis (PGD). The procedure is done about 3 -4 days after fertilization. Laboratory scientists remove a single cell from each embryo and screen the material for specific genetic disorders. According to the American Society for Reproductive Medicine, PGD can help parents decide which embryos to implant, which decreases the chance of passing a disorder onto a child. The technique is controversial and not offered at all centers.
 
Step 5: Embryo transfer
Embryos are placed into the woman’s womb 3 - 5 days after egg retrieval and fertilization. The procedure is done in the doctor’s office while the woman is awake. The doctor inserts a thin tube (catheter) containing the embryos into the woman’s vagina, through the cervix, and up into the womb. If an embryo sticks to (implants) in the lining of the womb and grows, pregnancy results.
More than one embryo may be placed into the womb at the same time, which can lead to twins, triplets, or more. The exact number of embryos transferred is a complex issue that depends on many factors, especially the woman’s age. Unused embryos may be frozen and implanted or donated at a later date.

* Why the procedure is performed?
http://www.webmd.com/infertility-and-reproduction/in-vitro-fertilization-for-infertility

* Risks of vitro fertilization:
http://health.howstuffworks.com/pregnancy-and-parenting/pregnancy/fertility/in-vitro-fertilization2.htm



Source: http://www.orchidrecoverycenter.com/womens-health/reproductive-technology/

http://www.nlm.nih.gov/medlineplus/ency/article/007279.htm

"Puberty Around the World"

ODD PUBERTY RITUALS

"Coming of age or reaching puberty is celebrated in many different ways around the world. In some cultures is a very important ritual marked by ceremonies while in other countries it is simply a birthday and the legal age for certain activities. Some of the countries that have distinct rituals also have very unusual rituals that are considered inhumane by some people and simply a part of life for other people."

* Paraguay and Brazil

In Paraguay and Brazil it is common for young girls who reach the age of puberty and have their first menstrual cycle to undergo tattooing. This is considered to be sexually attractive and not a form of pain. The girl is gouged with fish bone on the back, breast and stomach and then ashes are rubbed in the wounds to create a permanent tattoo. Although somewhat odd, this is the least painful and unusual of the rites of passage found around the word.

* Circumcision in many countries occurs shortly after birth; however, in some countries it is considered a coming of age rite that marks the young person’s movement from adolescence into adulthood. The ceremony is held for both young boys and girls who are judged to be ready for the rite. Although male circumcision is considered normal around the world, female circumcision or clitoridectomy is not the norm around the world some people consider cutting a female’s genitals to be inhumane and atrocious. Despite the controversy the circumcision of both boys and girls continues in many tribes around the world. However, female circumcision is becoming an option rather than an expectation in some tribes. Despite being an option many young girls choose to undergo this ritual to follow in the paths of her ancestors.

* Barabaig Culture of East Africa

Among the many different cultures of the world that have rites of passage for young men transitioning to adulthood are the Barabaig cattle herding tribe of East Africa. These people believe that shaving the boy’s heads and cutting them down to the bone from ear to ear in three deep horizontal cuts would make them into men. The resulting scar, called a ‘gar’, is a symbol of manhood and the boys who have it wear it with pride.




* Luiseno Indians
In the Luiseno Indian tribe young boys undergo a painful rite of passage but are not allowed to show their pain. Several painful ceremonial acts are required before the boy is recognized as a man by his tribe. The first of these is lying on a mound of ants for a period of time. The boy is not allowed to cry out or grimace in pain as his body is continually bitten by the ants. In a separate part of the ceremony boys are given tolocahe, a hallucinogenic drug that is supposed to help them see visions and become a man, if it didn’t kill them first.

 * Drunken-
With all the horrific acts being done to young people crossing over to adulthood it is good to look at lighter side of becoming adult that is the case in many other cultures. In many countries around the world a large majority of adolescents who reach adulthood spend their day of legal age imbibing in as many vices as they can legally do in order to show the world they are now adults. It might not be circumcision or a bed of ants, but the ensuing headache is usually one for the record books.

From tattoos to circumcision to drunken stupors rites of passage are common around the world. In some cultures these ceremonies or acts are little more than a fun time with friends and families meant to celebrate the legal coming of age; in other cultures the rites are serious and painful and meant to show the person has attained the maturity level to be an adult and handle the responsibilities that go with being an adult. In all cultures there is an unseen gap that one crosses from a child to an adult that is a time of great pride for the person crossing over.





Source: http://akorra.com/2010/10/10/top-10-odd-puberty-rituals/