My Classroom

Artificial skin

2011-01-15T05:41:00.000-08:00

The skin is the largest organ in the human body. Severe damage to large areas of skin exposes the human organism to dehydration and infections that can result in death.
Traditional ways of dealing with large losses of skin have been to use skin from other parts of a patient's body (such the thigh) or from a different person/cadaver. The former approach has the disadvantage that there may not be enough skin available, while the latter suffers from the possibility of rejection or infection.

To solve these issues, research is being done on artificial skin. Typically, a collagen scaffold is used (the protein that underlies the structure of skin), which can be additionally seeded with patient's own cells, or with foreskin from newborns that was removed during circumcision. Additional technologies, such as an autologous spray-on skin are being tested in efforts to accelerate healing and minimize scarring.

Children need love to grow smart

2009-08-12T07:13:00.000-07:00

When it comes to babies, infants, and pre-school kids – caring, love and attention really can make a chemical difference to the way our brains are formed. The effect will be permanent. Touch also does play a huge role in having a big baby.

Do cows have 4 stomachs

2009-07-11T03:04:00.000-07:00

Cows actually have one stomach divided into four compartments. These four compartments are called the rumen, reticulum, omasum, and the abomasum. The rumen is the largest compartment while the reticulum is the smallest.

The grass or digested material passes through each of these four chambers in turn and is slowly digested and the goodness drawn out. Each chamber works in the following ways:

1. The Rumen - This is the largest chamber and can hold up to 150-200 litres of partly digested food. The Rumen is full of good bacteria and this softens and helps digest the food. The bacteria ferments the carbohydrates in the food to allow the cow to produce energy. In doing so gas is produced (approx 500-1500 litres a day), approx 30% of this is methane gas and is expelled during belching. This is also how the foodstuff is passed from one chamber to the next

2. The Reticululum - This softens the food even further and forms it into small lumps of cud. The cud is returned to the cows mouth and chewed approx 40-60 times before being swallowed again. The reticulum also prevents large items from passing through the stomach this includes items which the cow has eaten which are not food, e.g plastic, packaging etc. Its like a safety mechanism for the cow. The material sits here and will not pass through to the next chamber, eventually the items will build up and the cow will vomit it back up.

3. The Omasum - This processes the cud further by pressing and breaking it up. It is then filtered. The omasum also regulates fluid absorbtion in the gut.

4. The Abomasum - This works similar to the human stomach. The food is finally digested by the stomach juices and the useful nutrients are absorbed by the blood. The waste is then pushed out into the intestines and finally out into a big smelly cow pat! Its a long journey for a bit of grass!

So next time you see a cow eating some grass in a field, bear in mind the work its stomach has to do just to digest that one mouthful of grass! Its not quite as simple as us having a quick munch of a snack.

How is litmus paper made?

2009-07-06T07:10:00.000-07:00

Litmus paper is made from lichens. Lichens are unique in that they are actually two distinct organisms, a fungus and an alga, living as one. Botanists classify lichens as fungi because it is the fungi that are considered to be responsible for sexual reproduction.

Approximately 15,000 different types of lichens have been identified. Lichens can be found growing on rocks, trees, and walls, in the soil and even under water in virtually all types of climates. Lichens are commonly used as gauge for environmental quality because they are sensitive to various pollutants. Several varieties of lichen are used to produce litmus. In fact, the Netherlands is one of the largest producers of litmus paper products.

The production of litmus paper has many features in common with paper manufacturing. In this process, the wood pulp is converted to paper, the paper is infused with the lichen solution, and the paper is dried and packaged.

Litmus paper is available in both red and blue varieties. The natural color for litmus paper is blue. When put in an acidic solution the blue paper turns red. Red litmus paper is first mixed with an acid when it is made. This causes the paper to appear red. When put in the presence of a base, the paper returns to its natural blue color.

What happens during an ultrasound scan in pregnancy

2009-07-01T08:26:00.000-07:00

Selecting the sex of the baby

2009-07-01T08:14:00.000-07:00

MicroSort®: The MicroSort® process sorts sperm by male and female by a process that measures differences in the DNA. Then using an intrauterine insemination (IUI) or in vitro fertilization (IVF) the enriched sample of sperm is used to help you conceive. About 92% of those attempting for a girl do conceive a girl, while the success rates for sex selection and boys using MicroSort® is lower at 81%. The pregnancy rate for using an IUI cycle is 15.6% and the overall IVF/ICSI clinical pregnancy rate is 32%.

Preimplantation Genetic Diagnosis (PGD): This is the most effective technique in sex selection. With nearly 100% accuracy and the ability to select not only sex but a healthy embryo makes it very popular. Though this is a costly and intensive method of sex selection that uses in vitro fertilization and does biopsies on the embryos before they are returned to the uterus.

Shettles Method: The Shettles Method is based on the fact that male and female sperm travel and survive in the reproductive tract for varying amounts of time. So you time intercourse about 12 hours prior to ovulation for a boy and several days before ovulation for a girl. This is a very simplified explanation of Shettles.

Ericsson Albumin Method: With Ericsson, the sperm is filtered through albumin and then an intrauterine insemination (IUI) is done with the sample. While the sample doesn't provide you with more of one particular sex, like a MicroSort® sample, it does help select the sex of the baby. For a girl, Clomid® is used since it has been shown to increase the number of girls.

Other Methods of Sex Selection: There are other methods of sex selection, including prepregnancy diets to alter the pH balance of your body, timing methods that differ from Shettles, O+12, supplements, and positioning. These low tech methods are not as accurate as MicroSort® and PGD and are sometimes dangerous.

NO ARMS AND LEGS

2008-11-10T18:36:00.000-08:00

Have you seen or heard of Nick Vujicic who lives without limbs ? Go check it out at http://www.lifewithoutlimbs.org/mbs.org/ on his touching stories and purposeful living.

Here is a little funny story shared by Nick:
My cousin is studying Nursing. They were learning about blood pressure etc. he puts his hand up and asks, "how would you take the blood pressure of a person who has no arms?" The lecturer thought he was being a bit "smart" with her, and replied that they'd simply then check it on the legs. And then guess what my cousin asks, "What if they have no legs either?" The lecturer feels threatened and furious and my cousin is sent out and told not to come back. We later find out that in an emergency, they'd have to stick a rod straight into my heart if I really needed it measured. So I'm in no hurry to measure my blood pressure.

Women in red wows men

2008-10-28T19:36:00.000-07:00

WASHINGTON (AFP) - - The popular ballad "Lady in Red" is poised to take on a whole new meaning: a study published Tuesday showed that the color red makes men see women as hotter or, more scientifically put, more attractive.

Researchers from the University of Rochester in New York conducted five psychological experiments to demonstrate that the color red makes men feel more amorous toward women.
In the experiments, groups of young men looked briefly at a picture of a moderately attractive woman printed on a red background, and the same woman then on a white, grey or green background. They also looked at a woman in red clothing, and the same one in blue clothing.
The men found the lady with a red background more attractive, both physically and sexually.
Comparing the woman in a red shirt to the same woman dressed in blue, men said they were more likely to ask the lady in red on a date and to lavish more money on her.
As part of one of the experiments, as well, the researchers sought to see whether a group of women were similarly more attracted to the woman shown against a red backdrop than a background of a different color. They were not.

What the researchers call the "red-sex link" could have roots in humans' biological heritage.
For instance, among primates, females display more red on parts of their body when they are nearing ovulation, probably to attract the male of the species.
"Research has shown that male primates are indeed particularly attracted to female conspecifics exhibiting red," the study says.

To the authors of the study, University of Rochester psychology professor Andrew Elliot and post-graduate researcher Daniela Niesta, the experiments' findings confirm what "women have long suspected and claimed: that men act like animals in the sexual realm."
And, they added, the fact that men are more turned on by women in red also confirms that, although men like to think that they respond to women "in a thoughtful and sophisticated manner, it appears that at least to some degree their preferences and predilections are, in a word, primitive."

Stem cells to grow a skull

2008-10-03T21:03:00.000-07:00

By extracting stem cells and growing them in a laboratory — to the point where there is enough quantity to infuse over a scaffold, doctors will then implant under the skin.
"In time, this will grow to form her own bone. The scaffold provides the shape and structure for the new bone to form."
Dr Goh believes stem cells placed directly in the skull may help Jamuna’s damaged brain nerves to recover, since these cells can differentiate to become either bone or nerve cells.
But this new method has so far been largely confined to animal experiments, with only one publicised human case in the United States.

Parts of the flower that can be eaten :)

2008-10-02T20:04:00.000-07:00

Many people find the concept of eating flowers to be a little strange - indeed there are a few who find the very idea to be distasteful.

Nutritionally, the flower can be divided into three main elements. Firstly, there is the pollen. Although only present in fairly small quantities, this is a very rich source of protein and so helps to build and maintain the body structure. Its flavour is usually rather bland.

Secondly, we have the nectar. This is usually rather sweet and is the substance that most attracts bees to the flowers to pollinate them. The bees turn the nectar into honey - when we eat the flowers we can use the sugars in the nectar to provide us with a good source of energy. Nectar provides a balanced form of sugars together with a range of minerals and does not have the negative effects of refined sugars such as rotting the teeth.

Finally, we have the petals and other parts of the flower structure. Although not normally as nutritious as leaves, they do have many similarities nutritionally and so can provide us with a good range of vitamins and minerals. Yellow flowers, in particular, are very good sources of vitamin A. The flavour and texture of flowers varies from species to species. Some are very crisp and crunchy, others almost silky soft. A few flowers have a very savoury taste whilst others can be very hot or have a very mild flavour. Depending on the quantities of nectar present, they can also be very sweet. If looking primarily for sweetness, by the way, you will normally be best off picking the flowers in the morning before bees and other insects have depleted the stocks of nectar.

Science Centre Visit on 2 Sept '08

2008-09-09T04:32:00.001-07:00

These are some of the photos that I took on my visit to the Singapore Science Centre. Check out the dodo bird and the dinos.....

Daddy, I'm in love... and he looks just like you!

2008-09-04T01:49:00.000-07:00

PARIS (AFP) - - Men tend to wind up with life partners who look like their mother, while a woman is lured to a partner who looks like her father, scientists reported on Wednesday.
Heterosexuals are deeply attracted to individuals whose faces are similar to that of their opposite-sex parent, they said, suggesting that this characteristic is rooted in an evolutionary drive.
A team led by Tamas Bereczkei at the University of Pecs in Hungary created a model of facial ratios -- width of jaw, distance between mouth and brow and so on -- comprising 14 facial zones.
They measured 312 Hungarian adults from 52 different families using this method. Each family included a couple, along with two sets of parents.
The researchers found a significant correlation in facial similarities between a woman's mate and her father, and also between a man's partner and his mother.
The team tested the model on faces that were randomly selected from the general population and repeated the experiment with a panel of judges, who also picked out the same pairings from randomly selected groups of photos.
Interestingly, men and women focused on different parts of the face when they home in on a potential mate, they found.
A man's lover and his mother tended to have similar fullness in the lips, width of mouth, as well as length and width of jaw.
But for women, the critical features were the distance between mouth and brow, the height of the face, distance between the eyes and the size of a man's nose.
The choices are driven less by psychology and socialisation and more by evolutionary pressures, suggests Bereczkei.
Too much genetic overlap -- as can happen with incest -- is an evolutionary no-no.
But seeking similar genetic traits "may confer individuals with additional adaptive advantages," he wrote.
It could increase the degree to which parents share genes with offspring, enhancing the genetic representation of future generations.
Finding similar partners might also help perpetuate genetic complexes that have evolved to adapt to a particular environment.
There may be an additional bonus, which probably has more to do with happiness than a genetic imperative.
"Human couples who are similar in physical and psychological characteristics are more likely to remain together than dissimilar partners, possibly leading to an increase in fertility," the study concludes.
The research appears in the journal Proceedings of the Royal Society B. The Royal Society is Britain's de-facto academy of sciences.

Comfort "food"

2008-08-27T18:10:00.000-07:00

I love the phrase “comfort food.” It speaks of the things that are so good, so familiar, so right, that they can always bring a smile to your face. For me, comfort food usually includes some form of beef and potatoes. Hamburgers and French fries. Meatloaf and mashed potatoes and gravy. Also, chocolate in almost any form imaginable. These are the foods that speak to me and say that all is well with the world. (I’m not saying they’re the most healthy!)
Unfortunately, all is not well with the world, and no amount of hamburgers and French fries can make it right. Real comfort is not the byproduct of specific foods any more than it is the result of alcohol or drugs or money or pleasure or power. It is a much deeper need that requires a much deeper solution.
Paul told the church at Rome that the search for comfort can begin in the pages of the Bible. He wrote, “Whatever things were written before were written for our learning, that we through the patience and comfort of the Scriptures might have hope” (Rom. 15:4).
God has given us His Word to draw us to Himself. Through a relationship with Him, He provides the comfort we need to live in a broken world. — Bill Crowder

Water Treatment

2008-08-21T00:57:00.000-07:00

The bacteria growth is negligible.... after chlorine is used to kill the bacteria in the muddy water....

Tuesday 19th 2008

2008-08-21T00:45:00.000-07:00

The smell of the fermented corn was terrible. The rest of the microrganism are also growing. Hence the terrible smell. Nonetheless, some students managed to distill out the alcohol from the mixture of corn, alcohol and water. Had a tiring but fun day.

Science Talent Management Programme 2008

2008-08-12T04:46:00.000-07:00

Science Talent Management Programme 2008 is a collaboration of our school, Chai Chee Secondary with Bedok Green and Bedok South Secondary. Every Tuesday, 5 students from Chai Chee, together with me, learn Science together. So far, we have made yoghurt, extract ethanol from corn and cleaned muddy water. The students will then return to school to teach the rest of the Lower Secondary classes as a post exam activity. More stories to come....