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CHALCONE AGAINST CANCER
Bright yellow crystals of spinochalcone A decorate the bottom of a flask. Cristina Castillo, an undergraduate pharmaceutical chemistry major at the Scientific Research Center of Yucatán in Mexico, isolated these crystals from Aeschynomene fascicularis, a plant used in Mayan traditional medicine. The experiment was part of her undergraduate thesis to determine how spinochalcone A affects cancer cells.
Congratulations to Kenneth Hanson, an assistant professor of chemistry at Florida State University, who photographed scattered light from two different laser beams, research that could lead to solar energy applications.
Hanson will receive a $50 cash prize. A Grand Prize winner will be selected at the end of the year. They will get their photograph published in C&EN and receive a Canon Digital SLR Camera.
In India, people sometimes adulterate milk with formaldehyde to increase the beverage’s shelf life. To develop a test to detect even minute amounts of the carcinogen in milk, Mahesh Agharkar and his colleagues at Pune University are investigating ways to increase the sensitivity of Tollen’s reagent, an aldehyde indicator, using gold nanoparticles. In the solutions shown, increasing concentrations of Tollen’s reagent (0 to 1,000 ppm, from right to left) interact with formaldehyde and gold nanoparticles to cause a color change.The researchers hope this preliminary research might one day lead to a visual indicator for tainted milk.
This TiO2 nanocage is the key component of a photocatalytic reactor that might one day be used to break down common organic pollutants in air and water. Researchers expose a titanium sheet studded with the nanocages, which are roughly 4 µm on each side, to contaminated air or water. Under ultraviolet light, the cages degrade pollutants such as formaldehyde and toluene almost 10 times as well as conventional TiO2 catalysts, the researchers say.
Under an ultraviolet lamp, thin-layer chromatography (TLC) plates glow with an eerie beauty. Used to monitor the progress of a reaction or as an initial purity test of a newly prepared chemical product, a pile of TLC plates like this is often the end result of a long day of chemical research.
Protibha Nath Banerjee of the University of Dodoma, in Tanzania, generates dimsyl potassium by reacting anhydrous dimethyl sulphoxide with potassium hydride under argon gas (filling the glove). He uses the dimsyl reagent to methylate polysaccharides that contain uronic acid moieties. Banerjee is trying to elucidate the structure of a polysaccharide isolated from apricot seeds to determine its potential use in medicine. Methylation analysis is among the best methods for elucidating the structure of complex polysaccharides.
During a lab experiment aimed at understanding human anatomy, Mirna Solís, an undergraduate chemistry student at the University of Guanajuato, Mexico, used an optical microscope to observe these stained neurons from a sample of nerve tissue.
Just in time for the Jewish High Holidays comes a Star of David catenane. The molecule, which was synthesized by chemists David A. Leigh, Robin G. Pritchard, and Alexander J. Stephens at the University of Manchester, in England, consists of two triply entwined 114-membered rings. “The Star of David catenane is the most highly entwined mechanically interlocked molecule made to date,” Leigh says. “Linking and entwining molecular rings may lead to new generations of materials that are strong but light and flexible.”
These oysters, collected from an estuary in Southern China, owe their blue color to contamination with metals including Cu, Zn, Ni, and Cr. Insufficient controls on industrial and domestic dumping into the water system threaten the viability of many Chinese villages that traditionally rely on rice and seafood for their meals, the researchers say. The blue oysters “are a cry for a national focus on metal pollution in estuaries in China.”
Transmission electron microscopy image of a gold nanotriangle that was stabilized during synthesis with extract from the peel of a grapefruit. Using peel extract in the future production of high-performance materials could be an additional source of revenue for farmers and could help provide a non-food-based market for agro-wastes.
Scattered light from two different laser beams, one blue (445 nm wavelength) and one green (532 nm), passes through a filter that allows all wavelengths of light to pass through except 532 nm. Kenneth Hanson, who took this photo, says filters like this are useful in measuring photon upconversion, a process in which multiple photons of a given wavelength get absorbed and then emitted at a shorter wavelength. Here, the filter allows emitted light (around 450 nm) to pass while filtering out the high-intensity absorbed light (532 nm). Scientists are eyeing photon upconversion for use in solar energy applications.