Tuesday, 18 July 2017

THE HUMAN PLASTINATION PROCESS


The 


Plastination 


Process




Even though a major German encyclopedia (the 19th edition of the Brockhaus Encyclopedia, 1992) indicates that the word "Plastination" is derived from the Greek (from plassein = to shape, to form), the term is, in fact, a creation of Gunther von Hagens. He coined the term because "plastification" already had a fixed meaning in the field of polymer chemistry, and the expression used in the original patents of 1977/78 ("Polymer Impregnation of Perishable, Biological Specimens”) was not terribly catchy and was utterly inadequate for popularizing the new technology, particularly abroad. The following will provide an explanation of how Plastination works. We will first present the process in a general, comprehensible manner; for those with an interest, we will then go into more detail regarding the chemicals and chemical processes used.


A process at the interface of the medical discipline of anatomy and modern polymer chemistry, Plastination makes it possible to preserve individual tissues and organs that have been removed from the body of the deceased as well as the entire body itself. Like most inventions, Plastination is simple in theory: in order to make a specimen permanent, decomposition must be halted. Decomposition is a natural process triggered initially by cell enzymes released after death and later completed when the body is colonized by putrefaction bacteria and other microorganisms. By removing water and fats from the tissue and replacing these with polymers, the Plastination process deprives bacteria of what they need to survive. Bodily fluids cannot, however, be replaced directly with polymers, because the two are chemically incompatible. Gunther von Hagens found a way around this problem: In the initial fluidexchange step, water in the tissues (which comprises approximately 70% of the human body) and fatty tissues are replaced with acetone, a solvent that readily evaporates. In the second step, the acetone is replaced with a polymer solution. The trick that first proved to be critical for pulling the liquid polymer into each and every cell is what he calls "forced vacuum impregnation." A specimen is placed in a vacuum chamber and the pressure is reduced to the point where the solvent boils. The acetone is suctioned out of the tissue at the moment it vaporizes, and the resulting vacuum in the specimen causes the polymer solution to permeate the tissue This exchange process is allowed to continue until all of the tissue has been completely saturated—while a matter of only a few days for thin slices, this step can take weeks for whole bodies.

The second trick is selecting the right polymer. For this purpose, "reactive polymers" are used, i.e., polymers that cure (polymerize) under specific conditions, such as the presence of light, heat, or certain gases. Their viscosity must be low, i.e., they have to be very thin liquids; they must be able to resist yellowing; and, of course, they must be compatible with human tissue. The polymer selected determines the look and feel of the finished specimen.

                      The Method of Plastination


Plastination is a relatively simple process designed to preserve the body for educational and instructional purposes.

Plastination, like many revolutionary inventions, is simple in concept:

1. Embalming and Anatomical Dissection
The first step of the process involves halting decay by pumping formalin into the body through the arteries.

Formalin kills all bacteria and chemically stops the decay of tissue.


Using dissection tools, the skin, fatty and connective tissues are removed in order to prepare the individual anatomical structures.



2.           Removal of Body Fat and Water
In the first step, the body water and soluble fats are dissolved from the body by placing it into a solvent bath (e.g., an acetone bath).




3. Forced Impregnation
This second exchange process is the central step in Plastination. During forced impregnation a reactive polymer, e.g., silicone rubber, replaces the acetone. To achieve this, the specimen is immersed in a polymer solution and placed in vacuum chamber.

 The vacuum removes the acetone from the specimen and helps the polymer to penetrate every last cell.



4. Positioning
After vacuum impregnation, the body is positioned as desired. Every single anatomical structure is properly aligned and fixed with the help of wires, needles, clamps, and foam blocks.


5. Curing (Hardening)
In the final step, the specimen is hardened. Depending on the polymer used, this is done with gas, light, or heat. Dissection and Plastination of an entire body requires about 1,500 working hours and normally takes about one year to complete.


    

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Preservation by Plastination
                       The study of biological specimens is significantly impeded by processes of decay. Thus, for centuries, people have been looking for appropriate methods of preservation. Thanks to the method of plastination, biological specimens can be prepared for research, teaching, and demonstration purposes in a lifelike and durable manner. To this end, in a vacuum process, specimens are impregnated with special reactive polymers. The mechanical (flexible or rigid) and optical (translucent or opaque) properties of the polymers used determine the characteristics of the preserved objects. Plastinated specimens are dry and odorless; they maintain their original surface relief and are identical to their state prior to preservation, down to the cellular level. Even histological studies can be performed on them.The method of plastination is based on replacing the water and fat contained in tissues with a reactive polymer such as silicone rubber, epoxy, or polyester resins: In a solvent bath, initially the tissue water is replaced by freeze substitution, and later, at room temperature, the tissue fats are gradually replaced by acetone. The dehydrated and degreased specimen subsequently is placed into the polymer solution. Under vacuum conditions, the solvent, in its gaseous state, is then continuously extracted from the specimen, creating a negative pressure that causes the polymer to gradually enter into the tissue. Following this process of “forced impregnation,“ the specimen is cured with gas, light, or heat, depending on the polymer used.
A special variation of plastination is “sheet plastination.“ With this method, specimens such as individual organs or entire bodies, mostly in a deep frozen state, first are cut or sawed into slices of 2 mm to 8 mm (about 1/12 inch to 1/3 inch) thickness. These slices, placed between polymer nettings, are then dehydrated, degreased, and eventually impregnated with polymer under vacuum conditions. In order to give the specimens a smooth surface, the impregnated slices are either cured between foil or in a flat chamber are casted with additional resin. The refractive index of the resin used determines the optical properties of the plastinated body slices: Epoxy resin yields translucency and good coloration of the various tissues; polyester resin, which is used for plastinating brain slices, allows for particularly good discrimination between white and gray brain matter.
Plastinated slices of organs and bodies constitute excellent teaching materials in cross-sectional anatomy, a field of ever increasing importance, and they correlate well with radiographic images. Serial sections of translucent body slices are useful in various scientific research approaches. In addition, they are a suitable diagnostic aid in pathology because they allow for quick macroscopic-diagnostic screening of entire organs and organ specimens. Pathologically modified tissue areas can then be selectively analyzed with conventional histological methods. Plastination was invented at the Anatomical Institute of Heidelberg University by Gunther von Hagens in 1977 and has been further refined since. By now, it has been generally recognized as a valid method of preservation and is practiced at more than 400 institutions in 40 countries. The main reasons for this wide-spread popularity of the method are the toughness, the durability, and the lifelikeness of the plastinates and the associated high teaching value.                 
   
   

Friday, 14 July 2017

HOW TO CONCEIVE A BABY BOY


How to conceive a boy



Some couples are almost desperate to conceive a baby of one particular gender. Fathers especially, can be eager to have a boy but there are also mothers who long for a son. Most couples however, are happy with either a boy or a girl baby, as long as it is healthy and strong. But if you are keen to try to sway the odds of having a boy then there is no harm in trying. Just remember that there are no guarantees and the odds of conceiving a boy or a girl are almost exactly the same for each and every pregnancy.
No matter what claims are made by companies asserting their skills in predicting whether a boy or girl will be conceived, don’t be too trusting. A lot of time, money, trust and energy can be wasted by couples who think they can consciously influence their baby’s gender. It’s worth remembering that the only scientifically proven strategy which can sway the odds, just slightly, is the timing of intercourse.
Diet, lunar calendars, sexual positions and even the boy/girl patterning within families do not change the likelihood of gender determination.
You can use this table below to read age(girl) of your partner and month that you need to get baby boy or girl.


Top tips for conceiving a boy

  • Time sex to coincide with the day of ovulation (no earlier than 24 hours before you are about to ovulate).
  • Deep penetrative sex is preferable.
  • It helps if the woman orgasms.
  • Have an energy drink, a cup of coffee or some chocolate before having sex.
  • Get your partner to trade in the tightie-whities for some boxer shorts. 

What’s a fact and what’s a fallacy?

  • Fact – men influence the gender of the baby, not women. Men provide the sperm which either has an X (girl) or Y (boy) linked sex chromosome.
  • There is no sure-fire guarantee of having a baby of a particular gender. Hoping and trying for a boy or girl is just that, and does not influence the odds in either direction.
  • One testicle does not produce girl sperm and the other boy sperm. Both produce an equal number of X and Y sperm and it is random chance, rather than management, which one fertilises the egg.
  • Some men do seem to produce better quality X or Y sperm which may account for the reason why particular families have large numbers of girls or boys.
  • Herbal and complementary medicine remedies do not impact on the likelihood of having a girl or a boy. They tend to offer spurious claims which are not based on scientific fact and reason.

Can’t I choose which sex my baby is?


At the current time in Australia, the only occasion when gender selection is done via fertility assistance is when there is a likelihood of the baby inheriting a sex linked disorder. Genetic counselling is often recommended as one part of an overall treatment regime. It is true that in some countries ‘designer babies’ are more common, with clinics freely advertising their success rates. Though the important issues of control over biology, quality of the parent/child relationship and expectations which may be placed on the ‘perfect’ child need to be thought about by parents very carefully in advance.

Characteristics of boy spermWhat this means to you
Are identified as looking like a YNothing really, just an interesting point.
Are not as resilient or strong as girl sperm.Interesting but nothing more.
Have short bursts of power before they fizzle out in energy.This affects the timing of sex to coincide with ovulation; don’t expect them to hang around.
Are not capable of fertilising the egg past 24 hours after they have left the man’s body.Timing sex to coincide with the day of ovulation may help slightly to increase the odds of having a boy.
Move at high speed towards the egg.Interesting but out of your control.



Characteristics of girl spermWhat this means to you
Are identified as looking like an X.Interesting – some people remember the differences because they claim that the extra arm on the x indicates more strength.
Are more resilient and live for longer than Y sperm. This means they can still fertilise the egg 4-5 days after they have left the man’s body.You don’t need to be so particular about timing sex to coincide with ovulation. Female sperm can wait around for longer until the egg is ready to be fertilised.
Require less ‘nurturing’ to find their way to the egg.Interesting, but you don’t need to do anything consciously to look after them. Just don’t douche.
Move more slowly than Y sperm but retain their energy.Again, you don’t need to do anything in particular.

Timing of intercourse

The timing of when a couple has sex is thought to actually make a difference in helping to conceive with a boy. It is one of the strategies suggested in The Shettles Method, which claims that the chances of having a boy are boosted when conception occurs as close to ovulation as possible. Boy or Y sperm are not as resilient as the X or female sperm, and according to Shettles it may help to provide a bit of additional support in supporting the Y sperm to get to their destination and not have to compete any more than they absolutely have to. Of course, this all depends on the willingness of a couple to track the woman’s ovulation and be available to each other over those crucial fertile hours.
According to Shettles, if you want a boy then avoid having sex:
  • no earlier than 24 hours before you are about to “ovulate”/conception/ovulation.
  • not after 12 hours since you have ovulated.
Shettles also advises that if couples want to conceive with a boy:
  • Best positions: deep penetrative sex is preferable. This helps to deposit the semen and sperm closest to the woman’s cervix so they are given the best opportunity to get to the egg in the fallopian tube. Twelve hours before ovulation is thought to maximise the chances of conceiving with a boy.
  • It also helps if the woman orgasms. This boosts the alkaline properties of the vagina which again, supports the sperm to do their work. Orgasm also causes uterine and vaginal contractions which help to push the sperm upwards where they need to go.

How do I know when I’ve ovulated?


  • Many women develop a distinctive pain on one side of their lower pelvis, which occurs mid-way through their monthly cycle.
  • Changes in the cervical mucous. Fertile mucous is clear, watery and stretchy – it appears similar to egg white. The cells change to encourage the smooth passage of sperm upwards through the cervix towards the fallopian tubes. Fertile mucous is also less acidic than non-fertile mucous and this environment favours the sperm rather than killing them off.
  • You could try using an ovulation testing kit. These detect hormonal changes which occur at ovulation, particularly an increase in Luteinizing Hormone. But there is still some disagreement over their effectiveness. Kits cost anywhere between $25.00 – $40.00.
  • You may feel different. Women who have ovulated and are at their most fertile often experience and increase in their libido, they appear more attractive and are more relaxed.
  • An increase in your basal body temperature. This is the lowest temperature which is attained by your body during rest and sleep. Just before ovulation occurs there is a rise in the temperature by a couple of degrees. If you are trying to conceive a boy, then it can be useful to chart your basal body temperature for a few months so you know your peak times of fertility.

General tips to help conceive a boy


  • Caffeine may help to give the Y laden sperm an additional boost. An energy drink, cup of coffee or even some chocolate before having sex won’t do any harm.
  • Suggest your partner change his underpants preference if he’s into the tighter briefs. Boxer shorts may look less glamorous but they don’t ‘hug’ the testicles close to the body and cause them to overheat. This in turn, can reduce the number of sperm which are produced and in turn, the likelihood of conceiving with a boy.

What about the food I’m eating?

It does seem that male sperm prefer an alkaline vaginal environment, which is where the correlation between diet and gender selection comes in. But whether or not eating a less acidic diet makes a difference is still open to debate. But it probably does no harm.
If you want to conceive a boy baby then you may want to consider eating less of these types of foods:
  • Spicy foods which contain vinegar, citrus juices and fruits and tart/tangy flavours.
  • Avoid eating dairy foods such as milk, cheese, youghurt and ice-cream.
  • Eat more foods which contain potassium such as bananas, broccoli, potatoes, spinach and brussel sprouts.
  • Some researchers believe that taking a daily supplement of Evening Primrose Oil boosts the chances of conceiving a boy.
Try eating more of these foods:
  • Bread, avocado, almonds, sprouts and wheatgrass.
  • Pine nuts and cherries.

PREGNANCY TEST

Pregnancy Tests



A pregnancy test may let you know, one way or the other, if you are pregnant.
Here are answers to some of the most common questions about pregnancy tests.


What is a pregnancy test and how does it work?


Pregnancy tests are designed to tell if your urine or blood contains a hormone calledhuman chorionic gonadotropin (hCG). This hormone is produced right after a fertilized egg attaches to the wall of a woman's uterus.
This usually happens -- but not always -- about six days after fertilization. If you're pregnant, levels of hCG continue to rise rapidly, doubling every two to three days.


What types of pregnancy tests are available?


Two main types of pregnancy tests can let you know if you're pregnant: urine tests and blood tests.

related content

 Early Signs of Pregnancy


Urine tests can be done at home or in a doctor's office. Many women first choose a home pregnancy test to take about a week after a missed periodHome pregnancy testsare private and convenient.
These products come with instructions. Follow them closely for the most accurate results. After testing, you can confirm results by seeing your doctor, who can perform even more sensitive pregnancy tests.
Blood tests are done at your doctor's office, but are used less often than urine tests. These tests can detect pregnancy earlier than a home pregnancy test, or about six to eight days after ovulation. But with these tests, it takes longer to get the results than with a home pregnancy test.
Two types of blood pregnancy tests are available:
A qualitative hCG test simply checks to see if hCG is present. It gives a "yes" or "no" answer to the question, "Are you pregnant?" Doctors often order these tests to confirm pregnancy as early as 10 days after a missed period. However, some of these tests can detect hCG much earlier.
A quantitative hCG test (beta hCG) measures the exact amount of hCG in your blood. It can find even very low levels of hCG. Because these pregnancy tests can measure the concentration of hCG, they may be helpful in tracking any problems during pregnancy. They may also (in combination with other tests) be used to rule out a tubal (ectopic) pregnancy or to monitor a woman after a miscarriage when hCG levels fall rapidly.

How accurate are pregnancy tests?


You should know that waiting at least a week after a missed period may give you the most accurate result. Results may also be more accurate if you do the test first thing in the morning, when your urine is more concentrated.
Urine home pregnancy tests are about 99% accurate. Blood tests are even more accurate than this.
How accurate a home pregnancy test is depends upon:
  • How closely you follow instructions.
  • When you ovulate in your cycle and how soon implantation occurs.
  • How soon after pregnancy you take the test.
  • The sensitivity of the pregnancy test
Home pregnancy tests are quick and easy to use. They are also very accurate if you carefully follow directions. These pregnancy tests all work in a similar way. You test the urine in one of these ways:
  • Hold the test's stick in your urine stream.
  • Collect urine in a cup and then dip the test's stick into it.
  • Collect urine in a cup and use a dropper to put urine into another container.
With all of these techniques, you need to wait a few minutes before seeing the results. Results may show up as a line, a color, or a symbol such as a "+" or "-" sign. Digital tests produce the words "pregnant" or "not pregnant."
If you have any questions about the pregnancy test or the results, call your doctor or the telephone number listed with the home pregnancy test.

What do the pregnancy test results mean?


It's important to know what a positive or negative result means.
If you get a positive result, you are pregnant. This is true no matter how faint the line, color, or sign is. If you get a positive result, you may want to call your doctor to talk about what comes next.
In very rare cases, you can have a false-positive result. This means you're not pregnant but the test says you are. You could have a false-positive result if blood or protein is present in your urine. And certain drugs, such as tranquilizers, anti-convulsants, or hypnotics, may also cause false-positive results.
If you get a negative result, you are likely not pregnant. However, you may still be pregnant if:
  • The test is past its expiration date.
  • You took the test the wrong way.
  • You tested too soon.
  • Your urine is too diluted because you consumed large amounts of fluid right before the test.
  • You are taking certain medications, such as diuretics or antihistamines.

Wednesday, 12 July 2017

TRICHOMONASIS DISEASE


Trichomoniasis 

two women and a couple

Most people who have trichomoniasis do not have any symptoms.

What is trichomoniasis?

Trichomoniasis (or “trich”) is a very common sexually transmitted disease (STD). It is caused by infection with a protozoan parasite called Trichomonas vaginalis. Although symptoms of the disease vary, most people who have the parasite cannot tell they are infected.

How common is trichomoniasis?

Trichomoniasis is the most common curable STD. In the United States, an estimated 3.7 million people have the infection. However, only about 30% develop any symptoms of trichomoniasis. Infection is more common in women than in men. Older women are more likely than younger women to have been infected with trichomoniasis.
Two Trichomonas vaginalis parasites, magnified (seen under a microscope)Two Trichomonas vaginalis parasites, magnified (seen under a microscope)

How do people get trichomoniasis?


The parasite passes from an infected person to an uninfected person during sex. In women, the most commonly infected part of the body is the lower genital tract (vulva, vagina, cervix, or urethra). In men, the most commonly infected body part is the inside of the penis (urethra). During sex, the parasite usually spreads from a penis to a vagina, or from a vagina to a penis. It can also spread from a vagina to another vagina. It is not common for the parasite to infect other body parts, like the hands, mouth, or anus. It is unclear why some people with the infection get symptoms while others do not. It probably depends on factors like a person’s age and overall health. Infected people without symptoms can still pass the infection on to others.

What are the signs and symptoms of trichomoniasis?


About 70% of infected people do not have any signs or symptoms. When trichomoniasis does cause symptoms, they can range from mild irritation to severe inflammation. Some people with symptoms get them within 5 to 28 days after being infected. Others do not develop symptoms until much later. Symptoms can come and go.
Men with trichomoniasis may notice:
  • Itching or irritation inside the penis;
  • Burning after urination or ejaculation;
  • Discharge from the penis.
Women with trichomoniasis may notice:
  • Itching, burning, redness or soreness of the genitals;
  • Discomfort with urination;
  • A change in their vaginal discharge (i.e., thin discharge or increased volume) that can be clear, white, yellowish, or greenish with an unusual fishy smell.
Having trichomoniasis can make it feel unpleasant to have sex. Without treatment, the infection can last for months or even years..
Photo of pregnant woman.Pregnancy

What are the complications of trichomoniasis?




Trichomoniasis can increase the risk of getting or spreading other sexually transmitted infections. For example, trichomoniasis can cause genital inflammation that makes it easier to get infected with HIV, or to pass the HIV virus on to a sex partner.

How does trichomoniasis affect a pregnant woman and her baby?



Pregnant women with trichomoniasis are more likely to have their babies too early (preterm delivery). Also, babies born to infected mothers are more likely to have a low birth weight (less than 5.5 pounds).

How is trichomoniasis diagnosed?


It is not possible to diagnose trichomoniasis based on symptoms alone. For both men and women, your health care provider can examine you and get a laboratory test to diagnose trichomoniasis.

What is the treatment for trichomoniasis?

Trichomoniasis can be treated with medication (either metronidazole or tinidazole). These pills are taken by mouth. It is safe for pregnant women to take this medication. It is not recommended to drink alcohol within 24 hours after taking this medication.
People who have been treated for trichomoniasis can get it again. About 1 in 5 people get infected again within 3 months after receiving treatment. To avoid getting reinfected, make sure that all of your sex partners get treated. Also, wait 7- 10 days after you and your partner have been treated to have sex again. Get checked again if your symptoms come back.

How can trichomoniasis be prevented?

The only way to avoid STDs is to not have vaginal, anal, or oral sex.
If you are sexually active, you can do the following things to lower your chances of getting trichomoniasis:
  • Be in a long-term mutually monogamous relationship with a partner who has been tested and has negative STD test results;
  • Use latex condoms the right way every time you have sex. This can lower your chances of getting trichomoniasis. But the parasite can infect areas that are not covered by a condom - so condoms may not fully protect you from getting trichomoniasis.
Another approach is to talk about the potential risk of STDs before you have sex with a new partner. That way you can make informed choices about the level of risk you are comfortable taking with your sex life.