Monthly Archives: November 2008

MIT Researcher Mimics Photosynthesis To Turn Water Into Hydrogen And Oxygen

A MIT researcher has demonstrated a reaction which resembles the photosynthesis process that plants make each day which means that from now on solar power could be deployed at world scale. Using catalysts developed by the chemist, he showed a video where oxygen was generated from water, just like plants do it in photosynthesis.

“I’m going to show you something I haven’t showed anybody yet,” said Daniel Nocera, the MIT chemist. After the lights were tuned off, he pointed to the video and asked – “Can you see that?” Then he explained – “Oxygen is pouring off of this electrode. This is the future. We’ve got the leaf.” This means that the most difficult obstacle was overcame as from now on we efficiently produce hydrogen gas by splitting water thanks to his catalysts.

This is very important as solar power could be deployed at worldwide and it could remove our dependence on fossil fuels. Solar power cannot replace oil with solar panels as solar cells are not very efficient and the sun doesn’t shine all day long. All this can change now, and we could use the catalysts and light to split water to generate hydrogen fuel which could power our cars. Also, according to Nocera, the catalysts could split seawater and if the hydrogen will be processed in a fuel cell then it will produce fresh water.

During recent history many scientists tried to get energy from the sun by resembling photosynthesis and their attempts were successful. The problem is that this process requires high temperatures, expensive catalysts, and harsh alkaline solutions, so it cannot be deployed at world-scale. Well, this will change as Nocera’s catalysts are cheap and they split water in oxygen and hydrogen at room temperature.

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A Doctor, a Mutation and a Potential Cure for AIDS

The startling case of an AIDS patient who underwent a bone marrow transplant to treat leukemia is stirring new hope that gene-therapy strategies on the far edges of AIDS research might someday cure the disease.

The patient, a 42-year-old American living in Berlin, is still recovering from his leukemia therapy, but he appears to have won his battle with AIDS. Doctors have not been able to detect the virus in his blood for more than 600 days, despite his having ceased all conventional AIDS medication. Normally when a patient stops taking AIDS drugs, the virus stampedes through the body within weeks, or days.

“I was very surprised,” said the doctor, Gero Hütter.

The breakthrough appears to be that Dr. Hütter, a soft-spoken hematologist who isn’t an AIDS specialist, deliberately replaced the patient’s bone marrow cells with those from a donor who has a naturally occurring genetic mutation that renders his cells immune to almost all strains of HIV, the virus that causes AIDS.

The development suggests a potential new therapeutic avenue and comes as the search for a cure has adopted new urgency. Many fear that current AIDS drugs aren’t sustainable. Known as antiretrovirals, the medications prevent the virus from replicating but must be taken every day for life and are expensive for poor countries where the disease runs rampant. Last year, AIDS killed two million people; 2.7 million more contracted the virus, so treatment costs will keep ballooning.

While cautioning that the Berlin case could be a fluke, David Baltimore, who won a Nobel prize for his research on tumor viruses, deemed it “a very good sign” and a virtual “proof of principle” for gene-therapy approaches. Dr. Baltimore and his colleague, University of California at Los Angeles researcher Irvin Chen, have developed a gene therapy strategy against HIV that works in a similar way to the Berlin case. Drs. Baltimore and Chen have formed a private company to develop the therapy.

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A neural code for three-dimensional object shape in macaque inferotemporal cortex

Previous investigations of the neural code for complex object shape have focused on two-dimensional pattern representation. This may be the primary mode for object vision given its simplicity and direct relation to the retinal image. In contrast, three-dimensional shape representation requires higher-dimensional coding derived from extensive computation. We found evidence for an explicit neural code for complex three-dimensional object shape. We used an evolutionary stimulus strategy and linear/nonlinear response models to characterize three-dimensional shape responses in macaque monkey inferotemporal cortex (IT). We found widespread tuning for three-dimensional spatial configurations of surface fragments characterized by their three-dimensional orientations and joint principal curvatures. Configural representation of three-dimensional shape could provide specific knowledge of object structure to support guidance of complex physical interactions and evaluation of object functionality and utility.
Introduction

A primary goal in the study of object vision is to decipher the neural code for complex object shape. At the retinal level, object shape is represented isomorphically (that is, replicated point for point) across a two-dimensional map comprising approximately 106 pixels. This isomorphic representation is far too unwieldy and unstable (as a result of continual changes in object position and orientation) to be useful for object perception. The ventral pathway of visual cortex1, 2 must transform the isomorphic image into a compact, stable neural code that efficiently captures the shape information needed for identification and other aspects of object vision.

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Scientists unlock secret of death protein’s activation

Scientists at Dana-Farber Cancer Institute have identified a previously undetected trigger point on a naturally occurring “death protein” that helps the body get rid of unwanted or diseased cells. They say it may be possible to exploit the newly found trigger as a target for designer drugs that would treat cancer by forcing malignant cells to commit suicide.

Loren Walensky, MD, PhD, pediatric oncologist and chemical biologist at Dana-Farber and Children’s Hospital Boston, and colleagues report in the Oct. 23 issue of the journal Nature that they directly activated this trigger on the “executioner” protein BAX, killing laboratory cells by setting in motion their self-destruct mechanism.

The researchers fashioned a peptide (a protein subunit) that precisely matched the shape of the newly found trigger site on the killer protein, which lies dormant in the cell’s interior until activated by cellular stress. When the peptide docked into the binding site, BAX was spurred into assassin mode. The activated BAX proteins flocked to the cell’s power plants, the mitochondria, where they poked holes in the mitochondria’s membranes, killing the cells. This process is called apoptosis, or programmed cell death.

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Major step forward in cell reprogramming

Imagine, if you can, a day within the next decade when a physician-scientist could remove a skin cell from your arm and with a few chemicals turn that fully formed adult cell into a dish of stem cells genetically matched to you.

That day came a giant step closer to reality on Oct. 12 with the publication in Nature Biotechnology of a report in which Harvard Stem Cell Institute (HSCI) researchers describe successfully having used a chemical in place of half the gene cocktail currently used to reprogram adult cells into induced pluripotent stem (iPS) cells.

“This study demonstrates there’s a possibility that instead of using genes and viruses to reprogram cells, one can use chemicals,” said Doug Melton, HSCI co-director and senior author of the study, whose first author is Danwei Huangfu, a postdoctoral fellow in Melton’s lab.

“The exciting thing about Danwei’s work is you can see how one might be able to sprinkle chemicals on cells and make stem cells,” said Melton, a Howard Hughes Medical Institute investigator, giving his postdoc credit for the experiment.

This publication marks Huangfu’s second success employing chemicals in reprogramming: Last year, working with mouse cells, Huangfu used a chemical to improve the efficiency of the gene-induced reprogramming process.

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Scientists Unwrap The Elements Of Life

Researchers at Newcastle University have taken a step forward in our understanding of how the fundamental building blocks of life are put together.

In a paper published in Nature, the team led by Professor Nigel Robinson have revealed a mechanism that ensures the right metal goes to the right protein. Proteins are essential and involved in just about every process in living cells.

Life, microbe, plant or human, is a painstaking assembly of trillions of atoms. The atoms include metals such as copper and manganese which act as catalysts in proteins. The proteins wrap around the metal atoms.

The research team has shown that to ensure a copper and a manganese protein wrap around the correct metal atoms, they do this in different parts of the cell, in zones which contain different metals. Therefore, which protein attaches to which metal is determined by where the folding action takes place in the cell.

Previously, a common view was that the right metals were simply those which were most attracted to the protein, but in this work that is not the case.

Professor Nigel Robinson at Newcastle University who led the research says: “This has taken us one step closer to understanding why metals and proteins assemble in the ways they do.”

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New solar cell material achieves almost 100% efficiency, could solve world-wide energy problems

Researchers at Ohio State University have accidentally discovered a new solar cell material capable of absorbing all of the sun’s visible light energy. The material is comprised of a hybrid of plastics, molybdenum and titanium. The team discovered it not only fluoresces (as most solar cells do), but also phosphoresces. Electrons in a phosphorescent state remain at a place where they can be “siphoned off” as electricity over 7 million times longer than those generated in a fluorescent state. This combination of materials also utilizes the entire visible spectrum of light energy, translating into a theoretical potential of almost 100% efficiency. Commercial products are still years away, but this foundational work may well pave the way for a truly renewable form of clean, global energy.

Traditional solar cell materials use a property called fluorescence to gather electricity. Energy from the sun strikes whatever material they are made of resulting in a momentary “dislodging” of electrons into an excited state. The excited electrons exist due to a property called fluorescence. They last only a dozen or so picoseconds (trillionths of a second) in this state, which is also called a “singlet state.” The many picosecond dwell there is fairly typical among traditional solar cell material in use today.

The new material, which was accidentally discovered using supercomputers to determine possible theoretical molecular configurations, causes not only fluorescing electrons in the singlet state to be created, but also phosphorescing electrons in what’s called a “triplet state.”

These triplet state electrons remain in their excited state of phosphorescence for scores of microseconds (up to about 200 microseconds, or 0.0002 seconds). With such a long lasting state of free electron flow, their ability to be captured is theoretically significantly greater than existing technologies.

And if the research team’s current efforts (of using only a few molecules of the hybrid materials suspended in a liquid solution) can be extended into practical real-world scales, then products yielding nearly 100% solar efficiency may soon be achievable.

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University researchers developing cancer-fighting beer

Have you ever picked up a cold, frosty beer on a hot summer’s day and thought that it simply couldn’t get any better?

Well, you may have to think again.

A team of researchers at Rice University in Houston is working to create a beer that could fight cancer and heart disease. Taylor Stevenson, a member of the six-student research team and a junior at Rice, said the team is using genetic engineering to create a beer that includes resveratrol, the disease-fighting chemical that’s been found in red wine.

Scientists at the University of Wisconsin in June had called resveratrol, which is a natural component of grapes, pomegranates and red wine, a key reason for the so-called French Paradox — the observation that French people have lower rates of heart disease despite a cuisine known for its cream sauces and decadent cheeses, all loaded with heart-clogging saturated fats.

The Wisconsin researchers had noted that adding small doses of resveratrol to the diet of middle-aged mice significantly slows their aging and keeps their hearts healthy. And they added that giving high doses to invertebrates extends their life spans, and high doses also stave off premature death in mice fed a high-fat diet.

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The computer, once a tool for scientists, is becoming a collaborator

Computer science — it’s not just about hardware and software anymore.

It’s about oceans, stars, cancer cells, proteins and networks of friends. Ken Birman, a computer science professor at Cornell University, says his discipline is on the way to becoming “the universal science,” a framework underpinning all others, including the social sciences.

An extravagant claim from someone with a vested interest? The essence of Birman’s assertion is that computers have gone from being a tool serving science — basically an improvement on the slide rule and abacus — to being part of the science. Consider these recent developments:

“Systems biologists” at Harvard Medical School have developed a “computational language” called “Little b” for modeling biological processes. Going beyond the familiar logical, arithmetic and control constructs of most languages, it reasons about biological data, learns from it, and incorporates past learning into new models and predictors of cells’ behaviors. Its creators call it a “scientific collaborator.”

Microsoft Research (MSR) is supporting a U.S.-Canadian consortium building an enormous underwater observatory on the Juan de Fuca Plate off the coast of Washington state. Project Neptune will connect thousands of chemical, geological and biological sensors on more than 1,000 miles of fiber-optic cables and will stream data continuously to scientists for as long as a decade. Researchers will be able to test their theories by looking at the data, but software tools that MSR is developing will search for patterns and events not anticipated by scientists and present their findings to the scientists.

Last year, researchers from Harvard Medical School and the University of California, San Diego, used statistical analysis to mine heart-disease data from 12,000 people in the Framingham Heart Study and learned that obesity appears to spread via social ties. They were able to construct social networks by employing previously unused information about acquaintances that had been gathered solely for the purpose of locating subjects during the 32-year study.

Computer scientists and plant biologists at Cornell developed algorithms to build and analyze 3-D maps of tomato proteins. They discovered the “plumping” factor that is responsible for the evolution of the tomato from a small berry to the big fruit we eat today. Researchers then devised an algorithm for matching 3-D shapes and used it to determine that the tomato-plumping gene fragment closely resembles an oncogene associated with human cancers. That work would have taken decades without computer science, researchers say.

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MIT Energy Storage Discovery Could Lead to ‘Unlimited’ Solar Power

Researchers at Massachusetts Institute of Technology (MIT) have discovered a new way of storing energy from sunlight that could lead to ‘unlimited’ solar power.

The process, loosely based on plant photosynthesis, uses solar energy to split water into hydrogen and oxygen gases. When needed, the gases can then be re-combined in a fuel cell, creating carbon-free electricity whether the sun is shining or not.

According to project leader Prof. Daniel Nocera, “This is the nirvana of what we’ve been talking about for years. Solar power has always been a limited, far-off solution. Now, we can seriously think about solar power as unlimited and soon.”

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