January 2011 Archives

The Science and Technology Foundation of Japan has announced that Japanese and US scientists have been named as laureates of the 2011 (27th) Japan Prize. Dr. Dennis M. Ritchie, 69, Distinguished Member of Technical Staff Emeritus, Bell Labs, and Dr. Ken Thompson, 67, Distinguished Engineer, Google Inc., have received the prize in this year's category of "Information and Communications" for developing the operating system (OS), UNIX, in 1969. Dr. Tadamitsu Kishimoto, 71, Professor Emeritus, Osaka University and Dr. Toshio Hirano, 63, Dean of the Graduate School of Medicine, Osaka University, were selected in the other prize category of "Bioscience and medical science" for their discovery of interleukin 6 (IL-6), a cell-signaling molecule in the immune system and its application in treating diseases. They will each receive a certificate of recognition and a commemorative gold medal at an award ceremony during Japan Prize Week in Tokyo on April 20, 2011. A cash award of 50 million Japanese yen (approximately US$600,000) will also be given to each field - this year the two laureates in each field will split the prize equally. The prize categories for the 2012 (28th) Japan Prize will be "Environment, Energy, Infrastructure" and "Healthcare, Medical Technology". For further information, visit the web page, http://www.japanprize.jp/en/index.html

Recently, a research group at Lawrence Berkeley National Laboratory reported an interesting application of X-ray absorption spectrometry to studies on the oxidation states of Co and CoPt nanoparticles in the presence of H₂ and O₂ at a controlled pressure. The key to the research lies in the specially developed gas reaction cell. For more information, see the paper, "In-situ X-ray Absorption Study of Evolution of Oxidation States and Structure of Cobalt in Co and CoPt Bimetallic Nanoparticles (4 nm) under Reducing (H₂) and Oxidizing (O₂) Environment", F. Zheng et al., Nano Lett., 11, 847 (2011).

Many readers of this news column are familiar with total-reflection X-ray fluorescence (TXRF). They also know that experiments can be done with a wavelength-dispersive mode, besides ordinary measurement with a silicon drift detector or a Si(Li) detector. If the spectrometer is optimized to see inelastic X-ray scattering spectra, what happens? Very recently, a research team led by Dr. P. H. Fuoss (Argonne National Laboratory, USA) published a very interesting report. The experiment used soft X-rays to observe the electronic structure of a 10-nm-thick La_0.6Sr_0.4CoO₃ epitaxial layer grown on a SrTiO₃ substrate. By comparing data acquired under total X-ray reflection and penetrating conditions, it was found that the O K-edge spectra from a 10 nm thin film and that from the underlying substrate can be separated successfully. For more information, see the papers, "Total-Reflection Inelastic X-Ray Scattering from a 10-nm Thick La0.6Sr0.4CoO3 Thin Film", T. T. Fister et al., Phys. Rev. Lett. 106, 037401 (2011).

Dr. S. Arzhantsev (Center for Drug Evaluation and Research, US Food and Drug Administration, St. Louis) and his colleagues have published some very interesting research. The research group is engaged in the determination of toxic metals in pharmaceutical materials using hand-held XRF spectrometers. It is extremely important with respect to toxic metal contamination to establish a reliable technique for classifying a large number of samples. As the procedure is basically a kind of pattern recognition, the problem that needs to be overcome is finding a suitable filter for signals and noises in XRF spectra. The research group chose a continuous Wavelet transform, which is an extension of short-time Fourier transform (STFT) and is capable of constructing a time-frequency representation of a signal that offers very good time and frequency localization. In the paper, they discussed the comparison of the signal-to-noise ratios at the energies of the elements of interest obtained by wavelet filtering and those obtained by the conventional empirical method. The results were evaluated in a collaborative study that involved 5 different hand-held XRF spectrometers used by multiple analysts in 6 separate laboratories across the United States, leading to more than 1200 measurements. The detection limits estimated for arsenic, lead, mercury, and chromium were 8, 14, 20, and 150 μg/g, respectively. For more information, see the paper, "Rapid Limit Tests for Metal Impurities in Pharmaceutical Materials by X-ray Fluorescence Spectroscopy Using Wavelet Transform Filtering", S. Arzhantsev et al., Anal. Chem., 83, 1061 (2011).