Category Archives: Science

CDC: Reduce Salt in Your Diet

USA Center for Disease Control: Application of Lower Sodium Intake Recommendations for Adults, 1999-2006 study

In 2005-2006, an estimated 29% of U.S. adults had hypertension (i.e., high blood pressure), and another 28% had prehypertension. The estimated average intake of sodium for those in the United States over 2 years old was 3,436 mg/day while the U.S. Department of Health and Human Services and U.S. Department of Agriculture recommended adults should consume no more than 2,300 mg/day of sodium (equal to approximately 1 tsp of salt), but those in specific groups (i.e., all persons with hypertension, all middle-aged and older adults, and all blacks) should consume no more than 1,500 mg/day of sodium (69% of U.S. adults should consume no more than !,500 mg/day). There is substantial evidence linking greater sodium intake to higher blood pressure.

Sodium reduction is recommended for persons with hypertension and as a first line of intervention for persons with prehypertension. Public health actions to reduce sodium intake likely will include reducing the sodium content of processed foods; encouraging consumption of more low-sodium foods, such as fruits and vegetables; and providing more relevant information about sodium in food labeling.

The current daily percentage value for sodium in the nutrition facts panel of packaged foods is based on a previous federal guideline of 2,400 mg/day and is likely to mislead the majority of consumers, for whom the 1,500 mg/day limit is applicable.

Image of the Common Cold Virus

image created by Dr. Jean-Yves Sgro, Institute for Molecular Virology, University of Wisconsin-Madison, from published X-ray data. larger image

Sequences capture the code of the common cold

Conducted by teams at the University of Maryland School of Medicine, UW-Madison and the J. Craig Venter Institute, the work to sequence and analyze the cold virus genomes lays a foundation for understanding the virus, its evolution and three-dimensional structure and, most importantly, for exposing vulnerabilities that could lead to the first effective cold remedies.

“We’ve had bits and pieces of these things for a long time,” says Ann Palmenberg, of UW-Madison’s Institute for Molecular Virology and the lead author of the new study. “Now, we have the full genome sequences and we can put them into evolutionary perspective.”

As its name implies, the common cold is an inescapable, highly contagious pathogen. Humans are constantly exposed to cold viruses, and each year adults may endure two to four infections, while schoolchildren can catch as many as 10 colds.

“We know a lot about the common cold virus,” Palmenberg explains, “but we didn’t know how their genomes encoded all that information. Now we do, and all kinds of new things are falling out.”
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The newly sequenced viruses also show, says Palmenberg, why it is unlikely we will ever have an effective, all-purpose cold vaccine: The existing reservoir of viruses worldwide is huge and, according to the new study, they have a tendency to swap genetic sequences when cells are infected by more than one virus, a phenomenon that can lead to new virus strains and clinical manifestations.
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The ability of different cold virus strains to swap genes and make entirely new strains was thought to be impossible, notes Claire M. Fraser-Liggett, a co-author of the new study and director of the Institute for Genome Sciences and professor of medicine and microbiology at the University of Maryland School of Medicine. “There is the possibility that this could lead to the emergence of a new rhinovirus strain with fairly dramatic properties,” says Fraser-Liggett.

Value of Prostate Cancer Screening Questioned by Two Studies

Ben Goldacre, in his bad science blog, again takes on journalist’s articles of health research in: Venal, misleading, pathetic, dangerous, stupid, and busted

1410 men would need to be screened to prevent one death. For each death prevented, 48 people would need to be treated: and prostate cancer treatment has a high risk of very serious side effects like impotence and incontinence. These figures are not hard to find: they are in the summary of the research paper.

For complex risk decisions like screening, it has been shown in three separate studies that patients, doctors, and NHS purchasing panels make more rational decisions about treatments and screening programmes when they are given the figures as real numbers, as I did above, instead of percentages. I’m not saying that PSA screening is either good or bad: I am saying that people deserve the figures in the clearest form possible so they can make their own mind up.
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So newspapers ignore one half of the evidence, and they fail to explain the other half properly.
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They can also link directly and transparently to scientific papers, which mainstream media still refuses to do. Journalists insist that we need professionals to mediate and explain science. From today’s story, their self belief seems truly laughable.

He also says some journalists got it right including the Washington Post in, Prostate Cancer Screening May Not Reduce Deaths:

The PSA blood test, which millions of men undergo each year, did not lower the death toll from the disease in the first decade of a U.S. government-funded study involving more than 76,000 men, researchers reported yesterday. The second study, released simultaneously, was a European trial involving more than 162,000 men that did find fewer deaths among those tested. But the reduction was relatively modest and the study showed that the tests resulted in a large number of men undergoing needless, often harmful treatment.

I think it is true that most people need help having science mediated to some extent. But he is also right that those doing so need to do better. And also everyone needs to learn about science to understand the choices they personally and politically (for policy issues) need to make decisions on. Being scientifically illiterate is dangerous.

Image of Viral Coat

image of exterior of virus - made up of 5 million atoms

High-energy X-ray diffraction was used to pinpoint some 5 million atoms in the protective protein coat of the PsV-F virus. The coat’s symmetrical features are shared by hundreds of viruses. The red and yellow sections illustrate how building blocks of four proteins come together to form the spherical shell.

The image reveals the structure of a type of protein coat shared by hundreds of known viruses containing double-stranded RNA genomes. The image was painstakingly created from hundreds of high-energy X-ray diffraction images and paints the clearest picture yet of the viruses’ genome-encasing shell called a “capsid.”

Viruses can reproduce themselves only by invading a host cell and highjacking its biochemical machinery. But when they invade, viruses need to seal off their genetic payload to prevent it from being destroyed by the cell’s protective mechanisms. Though there are more than 5,000 known viruses, including whole families that are marked by wide variations in genetic payload and other characteristics, most of them use either a helical or a spherical capsid.

“Spherical viruses like this have symmetry like a soccer ball or geodesic dome,” Pan said. “The whole capsid contains exactly 120 copies of a single protein.” Previous studies had shown that spherical capsids contain dozens of copies of the capsid protein, or CP, in an interlocking arrangement. The new research identified the sphere’s basic building block, a four-piece arrangement of CP molecules called a tetramer, which could also be building blocks for other viruses’ protein coats.

Full press release

MIT Faculty Open Access to Their Scholarly Articles

MIT faculty open access to their scholarly articles

In a move aimed at broadening access to MIT’s research and scholarship, faculty at the Massachusetts Institute of Technology have voted to make their scholarly articles available to the public for free and open access on the Web.

The new policy, which was approved unanimously at an MIT faculty meeting on Wednesday, March 18 and took immediate effect, emphasizes MIT’s commitment to disseminating the fruits of its research and scholarship as widely as possible.
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Under the new policy, faculty authors give MIT nonexclusive permission to disseminate their journal articles for open access through DSpace, an open-source software platform developed by the MIT Libraries and Hewlett Packard and launched in 2002. The policy gives MIT and its faculty the right to use and share the articles for any purpose other than to make a profit. Authors may opt out on a paper-by-paper basis.

MIT’s policy is the first faculty-driven, university-wide initiative of its kind in the United States. While Harvard and Stanford universities have implemented open access mandates at some of their schools, MIT is the first to fully implement the policy university-wide as a result of a faculty vote. MIT’s resolution is built on similar language adopted by the Harvard Faculty of Arts & Sciences in 2008.

It is good to see scientists putting advancing science above outdated journal business models. It is a bit of a shame that we have to be happy for such a small thing but given the state of those fighting against open science it is good to see those in favor of open access to science make progress.

Why People Often Get Sicker When They’re Stressed

Researchers at UT Southwestern Medical Center identified a receptor, known as QseE, which resides in a diarrhea-causing strain of E coli. The receptor senses stress cues from the bacterium’s host and helps the pathogen make the host ill. A receptor is a molecule on the surface of a cell that docks with other molecules, often signaling the cell to carry out a specific function.

Dr. Vanessa Sperandio, associate professor of microbiology at UT Southwestern and the study’’ senior author, said QseE is an important player in disease development because the stress cues it senses from a host, chiefly epinephrine and phosphate, are generally associated with blood poisoning, or sepsis.

“Patients with high levels of phosphate in the intestine have a much higher probability of developing sepsis due to systemic infection by intestinal bacteria,” Dr. Sperandio said. “If we can find out how bacteria sense these cues, then we can try to interfere in the process and prevent infection.”

Millions of potentially harmful bacteria exist in the human body, awaiting a signal from their host that it’s time to release their toxins. Without those signals, the bacteria pass through the digestive tract without infecting cells. What hasn’t been identified is how to prevent the release of those toxins.

“There’s obviously a lot of chemical signaling between host and bacteria going on, and we have very little information about which bacteria receptors recognize the host and vice versa,” Dr. Sperandio said. “We’re scratching at the tip of the iceberg on our knowledge of this.”

“When people are stressed they have more epinephrine and norepinephrine being released. Both of these human hormones activate the receptors QseC and QseE, which in turn trigger virulence. Hence, if you are stressed, you activate bacterial virulence.” Dr. Sperandio said the findings also suggest that there may be more going on at the genetic level in stress-induced illness than previously thought.

“The problem may not only be that the stress signals are weakening your immune system, but that you’re also priming some pathogens at the same time,” she said. “Then it’s a double-edged sword. You have a weakened immune system and pathogens exploiting it.”

Previous research by Dr. Sperandio found that phentolamine, an alpha blocker drug used to treat hypertension, and a new drug called LED209 prevent QseC from expressing its virulence genes in cells. Next she will test whether phentolamine has the same effect on QseE.

Full press release: Researchers probe mechanisms of infection

USA Losing Scientists and Engineers Educated in the USA

The USA continues to lose ground, in retaining the relative science and engineering strength it has retained for the last 50 plus years. As I have said before this trend is nearly inevitable – the challenge for the USA is to reduce the speed of their decline in relative position.

A new open access report, Losing the World’s Best and Brightest, explores the minds of current foreign science and engineering students that are studying in the USA. This is another in the list of reports on similar topics by Vivek Wadhwa and Richard Freeman. And again they point out the long term economic losses the USA is setting up by failing to retain the talent trained at our universities. It is a problem for the USA and a great benefit for countries like India and China.

“Foreign students receive nearly 60% of all engineering doctorates and more than half of all mathematics, computer sciences, physics and economics doctorates awarded in the United States. These foreign nationals end up making jobs, not taking jobs,” said Wadhwa. “They bring insights into growing global markets and fresh ideas. Research has shown that they even end up boosting innovation by U.S. inventors. Losing them is an economic tragedy.”

According to the study’s findings, very few foreign students would like to stay in the United States permanently—only 6% of Indian, 10 percent of Chinese and 15% of Europeans. And fewer foreign students than the historical norm expressed interest in staying in the United States after they graduate. Only 58% of Indian, 54% of Chinese and 40% of European students wish to stay for several years after graduation. Previous National Science Foundation research has shown 68% of foreigners who received science and engineering doctorates stayed for extended periods of time, including 73% of those who studied computer science. The five-year minimum stay rate was 92% for Chinese students and 85% for Indian students.

The vast majority of foreign student and 85% of Indians and Chinese and 72% of Europeans are concerned about obtaining work visas. 74% of Indians, 76% of Chinese, and 58% of Europeans are also worried about obtaining jobs in their fields. Students appear to be less concerned about getting permanent-resident visas than they are about short-term jobs. Only 38% of Indian students, 55% of Chinese, and 53% of Europeans expressed concerns about obtaining permanent residency in the USA.

On the tonight show yesterday, President Obama said

we need young people, instead of — a smart kid coming out of school, instead of wanting to be an investment banker, we need them to decide they want to be an engineer, they want to be a scientist, they want to be a doctor or a teacher.

And if we’re rewarding those kinds of things that actually contribute to making things and making people’s lives better, that’s going to put our economy on solid footing. We won’t have this kind of bubble-and-bust economy that we’ve gotten so caught up in for the last several years.

Eric Schmidt, Google CEO, recently expressed his frustration with the policies discouraging science and engineering graduates staying in the USA after they complete their education.

That is a brilliant [actually not brilliant at all] strategy take the best people hire them in American universities and then kick them out” It happens. “Its shocking.” It happens. “I know we are fighting against it.” “We America remain, by far the place of choice for education, particularly higher education.”

Nearly Half of Adults in the USA Don’t Know How Long it Takes the Earth to Circle the Sun

Questions:

How long does it take for the Earth to revolve around the Sun?
Did the earliest humans and dinosaurs live on the earth at the same time?
What percent of the Earth’s surface that is covered with water?

According to the national survey commissioned by the California Academy of Sciences: only 53% of adults know how long it takes for the Earth to revolve around the Sun; only 59% of adults know that the earliest humans and dinosaurs did not live at the same time; only 47% of adults can roughly approximate the percent of the Earth’s surface that is covered with water. Only 21% of adults answered all three questions correctly. I sure hope readers of this blog do much better than that.

Despite the fact that access to fresh water is likely to be one of the most pressing environmental issues over the coming years, less than 1% of U.S. adults know what percent of the planet’s water is fresh (the correct answer is 3%).

Answers: Continue reading →

Pi Ice Cube Trays

Pi ice cubes

Liven up a drink with Pi shaped Ice “cubes” from Think Geek:

But how about ice? You were planning to use that standard vaguely cubical stuff?… or worse the boring half-moon shape your fridge churns out? Well fear not intrepid nerdy party planner! ThinkGeek is here with the geekiest ice you’ll ever find… Pi ice! Yep these stylish silicone ice trays cast frozen H2O into the symbol for your favorite irrational number.

The Amazing Rusting Aluminum

when aluminum rusts, it forms aluminum oxide, an entirely different animal. In crystal form, aluminum oxide is called corundum, sapphire or ruby (depending on the color), and it is among the hardest substances known. If you wanted to design a strong, scratchproof coating to put on a metal, few things other than diamond would be better than aluminum oxide.

By rusting, aluminum is forming a protective coating that’s chemically identical to sapphire—transparent, impervious to air and many chemicals, and able to protect the surface from further rusting: As soon as a microscopically thin layer has formed, the rusting stops. (“Anodized” aluminum has been treated with acid and electricity to force it to grow an extra-thick layer of rust, because the more you have on the surface, the stronger and more scratch-resistant it is.)

This invisible barrier forms so quickly that aluminum seems, even in molten form, to be an inert metal. But this illusion can be shattered with aluminum’s archenemy, mercury. Applied to aluminum’s surface, mercury will infiltrate the metal and disrupt its protective coating, allowing it to “rust” (in the more destructive sense) continuously by preventing a new layer of oxide from forming.