Wednesday, September 30, 2009

Building Blocks

A QUANTUM OF SCIENCE

Geopolymers turn industrial wastes into energy-efficient super-building materials

Ordinary Portland Cement (OPC) is among the most common building materials on earth. Originating in the early British Industrial Revolution, it is used today in concrete, mortar, stucco and grout. An estimated 2.6 billion tons of it are made worldwide every year. Portland cement manufacture is a highly energy-intensive process involving high-temperature kilns, uses vast amounts of natural resources such as limestone, and produces not only considerable environmental damage in the form of alkaline run-off but also 5-8% of the total carbon emissions worldwide. But is there an alternative for this critical industrial material?

Geopolymers might just be that alternative. This new branch of industrial science explores methods for turning industrial waste products into highly energy-efficient materials with advanced properties. One of those industrial wastes is fly ash, the black powder left over from coal-burning power plants. At present, fly ash disposal is a tremendous industry problem with tremendous environmental impact. Recently, however, scientists have developed ways to use fly ash instead of limestone or other silicas and carbonates for the manufacture of concrete. These materials, known as geopolymers, not only make use of an abundant raw material but also present unique advantages for industrial use. Geopolymer concrete sets much faster than OPC, shows greater mechanical strength, shrinks less, is more resistant to corrosion and can withstand far higher temperatures without breaking down. Perhaps best of all, the production of geopolymer concrete reduces carbon emission by 90% compared to an equivalent amount of OPC.

Geopolymers are poised to provide other advantages as well. The mechanical strength and improved resistance to corrosion and heat make geopolymers ideal for sequestering environmentally harmful compounds such as arsenic, cadmium, chromium, lead, dioxins and even radioactive wastes. Challenges remain, however. Most importantly, long-term durability and stability data has yet to be generated, though ongoing tests suggest favorable performance compared to OPC. There are also existing regulations for OPC-based concrete products that would have to be modified if geopolymers are to gain acceptance and use worldwide, especially in the European Union where such regulations are strict. Still, the prospect of using industrial waste to make one of the most-used building materials on earth with improved characteristics while using less energy and adding less carbon to the planet seems an ideal solution.

For more information:

New Geopolymer Concrete Technology Created (R&D Magazine)

The role of inorganic polymer technology in the development of 'green concrete' (Duxson et al)

Geopolymerisation: A review and prospects for the minerals industry (Komnitsas et al)

Reaction mechanisms in the geopolymeric conversion of inorganic waste to useful products (Van Deventer et al)

Portland Cement (Wikipedia)


© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Monday, September 28, 2009

Prostate cancer - STD?

A QUANTUM OF SCIENCE

Mouse virus is implicated in causation of #2 male cancer killer

Prostate cancer strikes one in six American men, and is the second most likely cancer to cause death in men. New research now suggests that prostate cancer may in fact be linked to a virus that could be sexually transmitted.

The suspect is xenotropic murine leukemia-related virus (XMRV), a gammaretrovirus similar to viruses known to cause cancer in animals. Retroviruses are known cancer-causing agents because they integrate themselves into the host’s genetic material; when this takes place in or near a segment of DNA associated with a gene that controls growth, cancer – unrestricted cell growth – can result. Some retroviruses also contain cancer-causing genes of their own, such as the src gene in Rous sarcoma virus. The three most common cancer-causing viruses are human papilloma virus (HPV), Hepatitis B virus (Hep B), and the Eppstein Barr Virus (EBV).

Scientists working in collaboration between Columbia University and the University of Utah found XMRV in over 25% of prostate tissue samples, especially malignant ones. Moreover, the virus was found to be significantly more infective when present in semen. Another semen component, acid phosphatase, increased XMRV infectivity of human prostate cells by over 100-fold.

The strongest theory at present for the biology of XMRV-linked prostate cancer suggests that an infected man has viral particles present in his genital tract and deposits them in his partner when he has unprotected intercourse. The acid phosphatase in the semen activates the viral particles and makes them substantially more infective, making the partner at risk of transmitting the virus during future intercourse.

More research is needed to substantiate this theory, but this discovery could also lead to new treatments based on anti-retroviral therapies already known to medicine.


For more information:

Viral Cause For Prostate Cancer? (New Scientist)

Retroviruses (Wikipedia)


© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Lunar Oasis

A QUANTUM OF SCIENCE

Three separate space probes find spectral evidence of lunar water

In October 2008, India launched the Chandrayaan-1, its first lunar probe. The Chandrayaan-1 was designed to spend the following two years mapping the surface of the moon, but on August 31, 2009 contact with the probe was lost. Before then, however, the probe generated over 70,000 high-resolution images covering almost the entirety of the moon’s surface. Even more importantly, its sensors revealed a curious observation: ice.

Light absorbance is the characteristic interaction of different wavelengths of light with particular chemical elements. If a specific element is present in a material, it will absorb light of a characteristic wavelength. The same is true for simple compounds, such as water. With this technique, specific elements and often simple compounds can be detected even at interstellar distances, allowing scientists to deduce the chemical composition of distant stars. One compound that has a particularly characteristic absorbance spectrum is water. The Chandrayaan’s sensors reported a spectrum containing absorbance peaks consistent with water, and soon afterwards the observations were repeated by NASA’s Cassini and Deep Impact space probes.

Isn’t the moon a dry desert, though? Apollo astronauts certainly believed so when they landed on the moon in 1969, and "moon rocks" brought back from the lunar landing seemed to confirm it – except that it was assumed that any humidity found in the samples were the result of earth water contamination. Now, scientists theorize that water exists on the lunar surface in extremely thin layers just millimeters below the surface. The source and amount of water are still matters for further investigation, but scientists theorize that water on the surface of the moon might "migrate" as the moon is alternately warmed and cooled by exposure to the sun, until it ends up in deep lunar craters. These craters were recently found to be at a lower temperature than the surface of Pluto, so water ending up there would be "stuck" and accumulate over time.

The existence of water on the moon is particularly exciting not only because it was contrary to decades-old assumptions but also because it creates new possibilities. If it could be effectively harvested, lunar water could help sustain a human outpost on the lunar surface. Even more daringly, some have suggested that hydrogen and oxygen derived from electrochemically "splitting" this water could serve as rocket fuel. Rockets launched from the moon would require substantially less fuel because the moon’s gravity is so much less than that on Earth, leading to speculation that lunar launches could facilitate a new era in the exploration of the solar system, especially Mars.

For more information:

India's first lunar probe fails after less than a year (New Scientist)

Widespread water may cling to moon's surface (New Scientist)

How astronauts could 'harvest' water on the moon (New Scientist)

What Do Spectra Tell Us? (NASA)


© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Wednesday, September 16, 2009

Gene Therapy cures color-blindness in adult primates

A QUANTUM OF SCIENCE

This is the single biggest success story for gene therapy to date. Instead of reiterating, I will simply say: go read the linked articles and marvel that this could have come to pass in your lifetime.

"Looking back on this in 50 or 100 years, it will be a landmark paper even then."
-David Williams, director of the University of Rochester’s Center for Visual Science

FOR MORE INFORMATION:

Gene Therapy Cures Color-Blind Monkeys (Wired Science)

Original article: Gene therapy treatment of color blindness in adult primates (Mancuso et al)


© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Antioxidants Curb Cancer's Spread

A QUANTUM OF SCIENCE

New research shows reactive oxygen breaks down cell walls and helps cancer spread

Malignant cancer tumors have a unique characteristic: they can release tumor cells into the lymphatic system and cause tumors to grow elsewhere in the body, even in tissues or organs totally unrelated to those that were the original source of the tumor. This process is called metastasis, and sometimes forces doctors to use whole-body or systemic anti-cancer treatments when a localized treatment targeting a single tumor would be both more effective and far easier on the patient. Now scientist are advancing understanding of how metastasis occurs, and how to prevent it.

Researchers at Burnham Institute for Medical Research in La Jolla, California recently reported that reactive oxygen species were key players in the cellular process of metastasis. Reactive oxygen species (ROS) include superoxide, hydrogen peroxide and other forms of oxygen generated by the body’s normal functions. Some uses of ROS are beneficial, such as when the immune system generates ROS to kill invading cells. In cancerous cells, however, ROS help form lesions and break down cell walls, aiding in the spread of tumor-forming cells. Researchers have isolated a scaffold protein called Tks5 (for Tyrosine Kinase Substrate) which is concentrated in extruded lesions of tumor cells, called podosomes (or invadopodia in some papers). Tks5-rich cells rapidly produce ROS and form lesions that facilitate the spread of tumorous cells throughout the body. In their paper, Burnham scientists show that cells lacking the gene for Tks5 production are substantially inhibited from forming metastatic tumors, and treating the tumor cells with antioxidants similar suppresses the activity of Tks5, resulting in smaller tumors, fewer lesions/podosomes and a substantial decrease in extruded (metastatic) cells.

An example of tumor size reduction in cells lacking the Tks5 gene (4.20 and 4.24):

This paper is an exciting advance in the understanding of the basic processes of malignant cancer. If podosome formation and metastasis can be reduced by either antioxidant treatments or drugs that target Tks5, huge advances can be made in reducing the mortality associated with highly-metastatic malignant cancer.

For more information:

Reactive Oxygen’s Role in Metastasis

A role for the podosome/invadopodia scaffold protein Tks5 in tumor growth in vivo (Blouw et al)

Metastasis (Wikipedia article)

© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Tuesday, September 15, 2009

Old Flu Drug, New Hope

A QUANTUM OF SCIENCE

When vaccines fail, antiviral drugs might make the difference between life and death

The seasonal flu vaccine is already being administered and a special vaccine targeting H1N1 will soon follow, but for some people a vaccine may not be enough. Children, the elderly and immunocompromised individuals are at high risk for complications from influenza. For those already infected a vaccine does no good, but fortunately, antiviral medications are available when the flu turns life-threatening.

The most well-known anti-influenza drug is TamiFlu (its official name is Oseltamivir). TamiFlu is taken orally, usually for a five-day course of treatment. Approved in 1999, it has been used to treat 50 million people to date. Currently, TamiFlu is usually reserved for serious, potentially life-threatening cases in an attempt to prevent the flu virus from mutating into a form resistant to the drug. Indeed, five cases of TamiFlu-resistant H1N1 have already been reported but overall the rate of resistance flu cases remains low (around 1.2%).

Recently, a drug called Peramivir has been developed and is on the fast track to approval by the FDA. This is not a new drug – it was abandoned in 2001 by Johnson and Johnson due to low oral availability – but in 2005 concerns over Avian flu caused drug-makers to reexamine the compound and begin testing it as an intravenous medication. Recent studies show a single intravenous dose of Peramivir is as effective as the full five-day course of oral treatment with TamiFlu. Additionally, adverse drug reactions were less common with Peramivir.

Both TamiFlu and Peramivir act by inhibiting the same viral enzyme, neuraminidase. This enzyme allows viral particles to escape infected cells and go out in the bloodstream where they can find new cells to infect. When TamiFlu or Peramivir inhibit the viral neuraminidase, viral particles remain trapped inside infected cells until the body’s immune system can respond, usually with macrophages (literally "big eaters") that engulf the infected cell and digest it, destroying the viral particles along with the cell.

Additional advantages of Peramivir include its single-dose effectiveness. There have been reports of individuals hoarding TamiFlu pills and threatening the supply of the drug, but that cannot happen with a drug which can only be administered intravenously.


For more information:

Study: New Drug Fights Flu as Well as TamiFlu

TamiFlu (Wikipedia article)

TamiFlu-resistant H1N1 cases reported


© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Toward Better Vaccines

A QUANTUM OF SCIENCE

Making vaccines both optimally effective and optimally safe may be an easier task in the near future

Vaccines have an overwhelming track record when it comes to preventing illness, and thanks in part to conservative rules put in place by the federal agencies regulating them vaccines have also been extremely safe. Still, there’s an unadvertised trade-off in that compromise: vaccines would be even more effective than they are today if they could be made with heat-inactivated pathogens rather than highly purified microbial proteins generated in non-toxic bacteria, but that elevates the risk of possible immune reactions and side effects in those who take the vaccine.

To help improve the effectiveness of vaccines even when not using the heat-inactivated pathogens, scientists have long used compounds known as adjuvants to "boost" the body’s immune response. In essence, adjuvants are sensitizers that tell the body to be ready for an invader; when given as part of a vaccination, adjuvants significantly increase the vaccine’s protective effects both in duration and potency. But the only adjuvant ever approved for use in humans, aluminum hydroxide (or alum), is far from the most effective compound for the job. To date the FDA has been extremely reluctant to approve other, more powerful adjuvants for use with vaccines because of concerns about toxicity and possible side-effects.

Now scientists at Oregon State University have developed an adjuvant based on lecithin, a common food product, that shows six-fold greater immune response when administered as part of a vaccine as compared to alum-based treatments. Lecithin is part of a category of food products termed "generally recognized as safe" by the FDA, meaning that it is non-toxic in almost any dosage. This could mean a fast track to approval and, very possibly, vaccines that would be more effective, for longer periods of time, with smaller doses and fewer injections.

For more information:

New adjuvant could hold future of vaccine development

Adjuvant (Wikipedia article)

Strong antibody responses induced by protein antigens conjugated onto the surface of lecithin-based nanoparticles (Sloat et al)


© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Friday, September 11, 2009

A Weed No Longer

A QUANTUM OF SCIENCE

Latex production finds an unlikely source: dandelions

Latex is a complex emulsion of proteins, alkaloids, starches, sugars, oils, tannins, resins, and gums. In most plants, latex is white, but some have yellow, orange, or scarlet latex. Latex rubber comes from rubber trees, mostly found in South America, where industrial production of this common material has been severely impacted by fungal infections that threaten the entire industry.

The alternative? Dandelions.

The milky white juice that comes out of the stem when picked is a latex not unlike that found in rubber trees, except that it polymerizes immediately on contact with air. With some careful genetic work, scientists have developed a strain of dandelions lacking the enzyme that causes that polymerization, leading to the very real promise of industrial dandelion latex farms in the next five years. The best part of all is that latex from dandelions exhibits none of the immune rejection observed in latex rubber products, making it safe for use by hospitals and other important applications.

Dandelions: a weed no longer.

For more information:

Dandelion’s natural latex now used for rubber production

Latex (Wikipedia article)

© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Wednesday, September 9, 2009

Quantum: Tree Power!

A QUANTUM OF SCIENCE

"Green power" takes on a whole new meaning

Researchers at the University of Washington have discovered a way to "tap" the small but renewable electrical currents found in trees by investigators at MIT in 2008. Usually these microcurrents (200 millvolts or less) would be incapable of running even small circuits, but electrical engineers from the UW have built special "boost converters" that take a low incoming voltage and store it to produce a greater output.

This is an entirely new and very exciting field where much is currently unknown but the potential exists for a wide range of low-voltage devices that might one day help with everything from early wildfire alerts to climate-change sensors to methods for measuring tree vitality.

For more information:
News article from the UW

Source of Sustained Voltage Difference between the Xylem of a Potted Ficus benjamina Tree and Its Soil (Love et al, 2008)


© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation

Genetic Pastorale

A QUANTUM OF SCIENCE

Are cows responsible for the spread of a gene allowing humans to digest their milk?

Lactase is an enzyme that breaks down lactose, the disaccharide found in cow milk, into glucose and galactose.



This is important because lactose itself cannot serve as a source of energy for the human body, but glucose and galactose can. The gene encoding lactase can have either one or two copies and still produce enough lactase for carriers to process milk – humans lacking a copy cannot digest cow milk and are called lactose intolerant. Another term, "lactase persistence," refers to the strange stubbornness of the lactase gene, which is inherited in some human populations with far more frequency and fidelity than in other human populations.

Now a new publication shows statistical attempts to model the spread of lactase persistence in European populations as a correlate with how common dairying – raising cows for their milk – is in that region over the last, say, ten thousand years.

While it might seem intuitively obvious that intensive dairying would provide a strong selective pressure for a gene that makes cow milk digestible, this model shows exactly how strong that pressure is. Think about it this way: dairy cows were first domesticated around 9,000 years ago in the early Neolithic age. Since then, their presence has managed to exert a strong influence on human genetics, making those who raise them and care for them much more able to benefit from their milk. Before cattle were domesticated for milk (as opposed to for meat) there was little advantage for humans to possess even a single copy of the lactase gene; today, there is a sharp genetic profile between human populations associated with dairying and those that are not. This map, taken from the statistical modeling publication, shows how sharp that genetic profile is.



Researchers suggest, based on this model, that lactase persistence originated somewhere in the red area on the map around 7,500 years ago. This matches archeological evidence as well, showing the value of the model for predicting genetic drift over time and distance.

As much as human civilization has impacted the genetic destiny of the cow, the reverse is true as well. This begs the question: how many other creatures in our environment are shaping us, even now? It is easy to believe that Homo sapiens is the apex of the evolutionary ladder, but even the humble cow has some say in our genetic path.

For more information:

The Origins of Lactase Persistence in Europe (Itan et al)

Lactase (Wikipedia article)

Lactose intolerance (Wikipedia article)



© AQOS / P. Smalley (2009)
Reproduction with attribution is appreciation