ChemWeb Newsletter

Not a subscriber? Join now.June 27, 2006


This week the Alchemist discovers a chilly reminder of water's bizarre behavior that could make cryopreservation science fact rather than fiction, a new understanding of the underlying cause of Parkinson's disease, and discovers that Swiss chemists have peered into their crystal ball to find new materials and explain some old ones. Also in this week's Alchemical news round-up, simultaneous sensing for sensitive science and a way to clean up the infernal combustion.

A new discovery about yet another bizarre property of water could pave the way for cryopreservation. According to Anatoli Bogdan of the University of Helsinki, it might be possible to freeze the human body without devastating ice crystals forming in cells and bursting them. In medicine, cryopreservation is used to store sperm and embryos successfully, but whole organs are trickier because of the icy problem. Ice also seems to preclude the possibility of freezing someone before they die of an incurable disease and then thawing them out in years to come when a cure has been found. Bogdan's results suggest this may be possible outside of science fiction after all. He has found that he can produce low-density amorphous ice, or glassy water, by slowly supercooling aqueous droplets. When this glassy water melts it forms a highly viscous water, which Bogdan explains is not a new form of water, but because the freezing and melting processes side-step the crystal phase it could have implications for cryopreservation.

An explanation of why the brain cells that make dopamine go awry in Parkinson's disease could lead to new treatments for this debilitating disease. Susan Lindquist and Nancy Bonini of the Howard Hughes Medical Institute researchers have pinpointed defects in a critical cellular pathway that can lead to the death of dopamine-producing nerve cells and ultimately the symptoms of the disease. They have also found a way to rescue dying neurons in several animal models of Parkinson's disease, which could offer hope of developing new drugs to fight the underlying cause. Lindquist cautions that the findings are yet to be confirmed in people. "However," she says, "given the fact that we've found the same results in yeast, flies, worms and rat neurons, I would be very surprised if we didn't find that they were relevant in humans."

Swiss researchers have used a new crystal structure prediction program to systematically explore the high-pressure chemistry of molecular elements, including hydrogen and oxygen. Their surprising predictions suggest that novel forms exist. For instance, hydrogen and oxygen should remain molecular at pressures up to 6 Mbar and 2.5 Mbar, respectively. Additionally, the researcher predicted the unique structures of red and black oxygen as well as suggesting several novel carbon allotropes that might have unique physical properties. Artem Oganov and colleagues at ETH Zurich reckon their structure predictions resolve several longstanding debates in chemistry as well as offering opportunities for making new and useful materials.

A new type of sensor that can measure carbon dioxide and oxygen levels simultaneously without interference has been devised by Otto Wolfbeis and colleagues at the University of Regensburg in Germany. The sensor could revolutionize studies of plant respiration and photosynthesis, an area until now plagued by interference in which only one of the two gases could be determined at a time. It could also have application in the food and drink industry as well as in the biotech industry where fermentation and related plant processes are important. "It is likely to become a powerful tool in combinatorial microbiology, in cell-based screening for drugs, and in biomonitoring in general," Wolfbeis explains. "In combination with fiber optic microsensors, in vivo sensing of oxygen and carbon dioxide should be possible."

Researchers at Georgia Institute of Technology have developed a new type of combustion chamber for engine or gas turbines that burns with lower emissions than conventional engineering. Nitrogen oxides (NOx) and carbon monoxide emissions from this combustor are almost zero, according to Ben Zinn and colleagues. "We must burn fuel to power aircrafts and generate electricity for our homes. The combustion community is working very hard to find ways to burn the fuel completely and derive all of its energy while minimizing emissions," says Zinn. Called the Stagnation Point Reverse Flow Combustor, the Georgia Tech device, originally developed for NASA, significantly reduces NOx and CO emissions in a variety of aircraft engines and gas turbines that burn gaseous or liquid fuels. It burns fuel with NOx emissions below 1 parts per million (ppm) and CO emissions lower than 10 ppm, significantly lower than emissions produced by other combustors.

Not a subscriber? Join now.June 13, 2006


This week the Alchemist discovers there may be no need for a magic bullet in cancer chemotherapy and a basic approach could be all that is needed. He also finds a smashing discovery that could explains glassy substances and precludes an ideal standard. Also in this week's issue, we learn that the ozone layer is finally on the mend, and hear about a co-polymer that not only fends of barnacles but can smell nice too. Finally, spontaneous chiral resolution with achiral ligands.

Jeffrey Krise and colleagues at the University of Kansas at Lawrence have found a simple way to improve chemotherapy drugs, which works by making them basic. The new approach should allow anticancer drugs to accumulate in both normal and malignant cells, but be active only in the latter. The approach side-steps the issue of finding a magic bullet method of targeting cancer cells only and works because unlike healthy cells, cancer cells have an impaired ability to isolate and excrete basic substances, and so get hit with the full cytotoxic effect of the drug. "It could allow cancer patients to tolerate higher and more effective doses of chemotherapy before normal cells are damaged to an extent that causes serious side effects and cessation of therapy," Krise explains.

Princeton chemists have discovered that the formation of a glass always occurs differently depending on how quickly a liquid substance is cooled into its solid form. Researchers had suggested that an ideal glass passes through a transition point on cooling at which it snaps from disordered liquid into a solid-state order. Sal Torquato and colleagues at Princeton University performed a computer simulation of the transition and could see no well-defined transition point. The findings could have implications as far reaching as how to make better golf club heads and to understanding the structure of the early universe. Torquato explains, "Golf club heads made of metallic glasses, for example, can make golf balls fly farther. While our research could be utilized by industry, it can actually help us understand any 'glassy' multi-particle system, such as the early universe - which cosmologists have described as a glass." Their findings, published on June 6 in Physical Review Letters, also smash any chance of materials scientists finding the ideal glass.

While global warming and climate change in general remain high on the scientific and political agendas, one of the more stubborn environmental problems of the last half century, the emergence of "holes" in the stratospheric ozone layer seems, at last, to be in reverse. The enforcement of 1987's Montreal Protocol, which was to ban the use and release of ozone-eating pollutants, seems to have had some impact, after all. However, according to NASA scientists, for the last 9 years, worldwide ozone has remained roughly constant, halting the decline first noticed in the 1980s. The hole above Antarctica remains a gaping maw, but the holes elsewhere in our atmosphere seem to be healing. Whether or not this is due to Montreal cannot be said with certainty because the ozone layer can also be affected by the weather, volcanic activity, and sunspots.

A material originally developed by US chemists for use as a marine "antifouling" coating has now been shown to capture fragrance molecules and release them at room temperature. The research team, led by Karen Wooley and James McDonnellv of Washington University in St. Louis say their polymeric material has a remarkable nanostructure that could be exploited for repelling pests, adding fragrance to the air or even as a nasal spray for administering certain drugs. Wooley fused two normally incompatible polymers - a hyperbranched fluoropolymer and a linear polyethylene glycol - let them phase-separate into distinct domains, one interspersed in the other and then cross-linked them to form the product. The resulting material is a heterogeneous, yet nanoscopically mountainous, coating with hydrophilic and hydrophobic ranges, in which barnacles cannot get a foothold. "We have these channels to serve as capillaries to take in guest molecules and hold them inside the material," explains Wooley, and as such guest fragrance molecules, or other species such as insect repellant or a drug, can be trapped by the materials and released subsequently under the right conditions.

It's the Holy Grail for many chemists - a solution to the problem of how to separate enantiomers, without using complicated chiral processes. Many have tried, many have failed, now we must hand it to Chinese researchers who claim to have cracked the chiral code. Chunying Duan and colleagues at Nanjing University observed spontaneous resolution of silver helicates without using any chiral additive. The key lies in the how the ligand bonds to the first metal center and passes on the chirality as the helix forms. C-H…pi and pi-pi stacking in the aromatic centers of the ligands result in only one handed form of the helicate forming and crystallizing.