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Woolly Mammoth Extinction

Submitted by johanthomas on Fri, 03/03/2017 - 13:07

Researchers compared ancient wooly mammoth DNA from 45,000 years ago to woolly mammoth DNA from just 4,000 years ago to try to see why they died out. 45,000 years ago mammoth populations were much larger than 4,000 years ago. The more recent animals had "this huge excess of what looked like bad mutationes in the genome" - Dr Rebekah Rogers of the University of California, Berkley. Towards the begining of their extinction, scientists theorize the mammoths had lost their sense of smell, remained isolated, and had a shiny coat. This could have occured because mammoths had many small group populations which limited genetic diversity. Researchers at Berkley want to use this knowledge to prevent extinction of mammals like the panda, mountain gorrilla, and indian elephant. If these animals reduce in population too much, they will still have low genetic diveristy if they can build their numbers back up.

Regenerating pancreas

Submitted by johanthomas on Fri, 02/24/2017 - 13:22

Dr. Valter Longo published in Cell journal a potential new therapy to treat diabetes. He cycled a special diet in mice to regenerate beta cells in the pancreas which release insulin in the presence of sugar in the blood. The diet involved starving the mice and then feeding them again in cycles. The equivalent diet in humans would be low protein, low carbohydrate, and high unsaturated fats (very low calorie) for 5 days, and then eating whatever they want for 25 days. Experiments in mice showed improvement in both type 1 and type 2 diabetes. Type 1 diabetes is caused by the immune system destroying beta cells in the pancreas. Type 2 diabetes is caused by an accumulated resistance to insulin by overexposure (unhealthy lifestyle). Dr. Longo stated: "Scientifically, the findings are perhaps even more important because we've shown that you can use diet to reprogram cells without having to make any genetic alterations." When trying the diet with humans results included weight loss, lower blood pressure, lower levels of the cancer causing hormone IGF-1, and improved blood sugar levels.

Dr. Longo does not advise anyone to try this diet without the approval of a medical expert because it is more complex than people realize.

Manuscript Submission Guidelines

Submitted by johanthomas on Fri, 02/24/2017 - 12:55

The American Journal of Tropical Medicine and Hygiene has its submission guidelines posted at the website:

To submit a manuscript the following components are necessary:

A cover letter, the title of the manuscript, a description of the significance of the manuscript, a confirmation that the manuscript is original work, disclosure of all conflicts of interest, names and signiatures of all authors, and the completion of a copyright form.

There are also specific formatting styles the journal requires to keep the material consistent and understandable.

Induced pluripotent stem cells

Submitted by johanthomas on Wed, 02/15/2017 - 23:37

Stem cells can differentiate into any cell in a multicellular organism. Stem cell research has potential to pioneer an entirely unique way to study and treat disease. Stem cells are most commonly found in embryos. There is a lot of contraversy in the ethics of harvesting human embryonic stem cells because it destroys the embryo. In 2007, researchers developed a method to undifferentiate skin cells into stem cells. Almost all cells in an organism has the same DNA. Differentiated cells only translate and "switch on" certain genes to function in a particular way -- cell programming. This method involves finding the genetic switches to program stem cells and artifically switch them on to reset the cell function. The research team found these switches by reducing the 20,000 possible gene candidates to about 100 using gene databases. The team used knockout mice to evaluate each gene candidate's ability to make pluripotent stem cells. After 3 years and hundreds of thousands of cell cultures, the team narrowed the candidates to 4 genes. A virus was used to insert the 4 genes into mice skin cells and within 4 weeks the skin cells completely converted into stem cells. These induced pluripotent stem cells were indistingiushable from embryonic stem cells. Now, we have the method and ability to convert human skin cells into pluripotent stem cells.

Drug resistant tuberculosis

Submitted by johanthomas on Wed, 02/15/2017 - 23:18

Tuberculosis (TB) is an airborne bacterial disease usually affecting the lungs, but can also affect the brain, kidneys, or spine. This disease is lethal, but curable with early intervention and proper treatment. Drug resistant TB can emerge when an infected patient does not complete a full treatment cycle, healthcare providers perscribe the wrong treatment dose or length of time, or if the drugs are of poor quality. TB is treated with isoniazid and rifampin (the most potent therapies to cure TB), but multidrug-resistant TB can be resistant to both treatments. Extensively drug-resistant TB is resistant to both isoniazid and rifampin, as well as fluoroquinolone and at least one of the three injectable second-line drugs. Drug-resistant TB (and especially extensively drug-resistant TB) is very complicated and expensive to cure ranging from 18,000 to 494,000 dollars for treatment.

How to grow a kidney

Submitted by johanthomas on Wed, 02/15/2017 - 22:57

Scientists in Massachusetts General Hospital are harvesting dead organs and processing them to be transplanted into live organisms. These researchers are "reanimating" hearts, lungs, limbs, and kidneys. A donor organ which would not be suitable for transplantation is suspended in a soapy solution to wash away native cells only leaving behind structural proteins. The organ can then be repopulated with stem cells to recreate a functional organ. The research team led by Harold Ott created a pressure gradient within the suspention fluid of the organ to suck the stem cell into the proper place in the empty organ structure. The organs are placed into an environment mimicing the body (temperature, nutrients, oxygen). The tissue becomes functional after just a few days of growth. Kidneys grown in this lab are even able to produce urine. After culturing the new organ, it can be transplanted into an animal model -- rats. One of the most challenging parts of this research was creating the perfect pressure gradient to deliver the stem cells to the correct place in the organ. Done incorrectly, the organ will just dissociate and fall apart in the bioreactor. Harold Ott theorizes this method can be applied to any tissue or organ to potentially save many lives.

Bird flight formation

Submitted by johanthomas on Wed, 02/15/2017 - 22:37

Bird fly in a V formation. Researches theorize the reason behind the phenomena exists. Data shows that birds in the lead (front of the V) have a higher metabolic rate than the birds at the back of the V -- the birds in the front are working hard than the birds in the back. As each bird in the formation flaps its wings, it oscilates the air behind it. The birds in the back can time their flap rate to be in phase with the air oscillation and benefit from the rise in air current of the wave. This is maximizes the efficiency (minimizes the energy output) of the birds in flight durring a migration where they often have to travel hundreds of miles. The V formation reduces wind resistance and can increase the flight range of birds by up to 71%. Research into bird migration is difficult because birds cannot fly with too much extra weight. Even if a researcher attaches a camera or a biosensor to measure heart rate and body function, the equipment is expensive and will probably never be seen again to collect the data. One effective method to study birds in flight is utilized by the Waldrapp Team in Europe. A researcher raises the birds (the birds imprint on the researcher) and are trained to fly behind the researcher in a helicopter. The airodynamic positioning of birds in flight can be observed using this method.

Hammerhead sharks

Submitted by johanthomas on Wed, 02/15/2017 - 22:17

Because of climate change and rising ocean temperatures -- El Niño -- many fish and coral species are suffering from changes in temperature and pH levels of the water. Parasites and infections proliferate in wounds on hammerhead sharks. Durring mating, male sharks cling to the female using their teeth. Hammerheads travel by the hundreds to seek out cleaner fish which eat the parasites and clean out their wounds. This accelerates healing and in return the hammerhead sharks do not prey on the fish. This is an example of mutualistic symbiosis: both species interact in a way to benefit each other.

30 minute observation of a worm

Submitted by johanthomas on Thu, 02/02/2017 - 23:56

The worm is a tan brown/white color 25mm long and 5mm across at its widest point. It is composed of a head, 10 body segments, and a tail. The worm has a tail split into two distinct segments. It was bilaterally split by a vein running down it's back. This dorsal vein pumped blood at a rate of 10 pumps per 11.22 seconds.The worm has 14 legs in 7 pairs. Three pairs are located underneath its head and four pairs are located around the middle of the underside. The legs have grip: the worn us able to lift up woodent shavings. The head of the worm is surrounded by fine hairs. These hairs do not respond to touch. The worm responds defensively when something comes in contact with its skin, not its hairs.



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