Blue, green and 0.8 μm Tm, Ho doped upconversion laser glasses, sensitized by Yb

To obtain efficient upconversion laser glass, the optical properties of Tm³⁺ and Ho³⁺ were investigated in various glasses. Fluoride glass was selected as base glass for upconversion. The efficient upconversion fluorescences corresponding to the ¹G₄→³H₆ and ³H₄→³H₆ transitions of Tm³⁺ and the ⁵S₂→⁵I₈ transition of Ho³⁺ were observed in Yb³⁺-Tm³⁺ and Yb³⁺-Ho³⁺ doped aluminozircofluoride glasses excited at 980 nm. The very stronge blue and green emission light can be observed visually. The upconversion processes observed were two-photon processes for ³F₄→³H₆, ⁵S₂→⁵I₈ transitions and three-photon processes for the ¹G₄→³H₆ transition and can be described by a rate equation model. The energy transfer and energy back-transfer were analyzed in Yb³⁺-Tm³⁺ and Yb³⁺-Ho³⁺ systems. The relationship between emission intensity, pumping intensity and dopant concentrations is described using a rate equation model and shows good agreement with experiments. The dynamics of excited state ( ) is also analyzed with the diffusion-limited model based on Yokota-Tanimoto theory.     

Stabilization of a new antiulcer drug (Lansoprazole) in the solid dosage forms

In the previous study, we clarified that enteric granules were appropriate dosage forms of lansoprazole. The establishment of these formulations, however, was difficult because some of the excipients needed for these formulations are incompatible with the drug. We examined the effects of adding magnesium carbonate as an alkaline stabilizer and could get stable enteric granules. We also discuss the mechanism of stabilization.     

Individual Variations in Inorganic Arsenic Metabolism Associated with AS3MT Genetic Polymorphisms

Individual variations in inorganic arsenic metabolism may influence the toxic effects. Arsenic (+3 oxidation state) methyltransferase (AS3MT) that can catalyze the transfer of a methyl group from S-adenosyl-l-methionine (AdoMet) to trivalent arsenical, may play a role in arsenic metabolism in humans. Since the genetic polymorphisms of AS3MT gene may be associated with the susceptibility to inorganic arsenic toxicity, relationships of several single nucleotide polymorphisms (SNPs) in AS3MT with inorganic arsenic metabolism have been investigated. Here, we summarize our recent findings and other previous studies on the inorganic arsenic metabolism and AS3MT genetic polymorphisms in humans. Results of genotype dependent differences in arsenic metabolism for most of SNPs in AS3MT were Inconsistent throughout the studies. Nevertheless, two SNPs, AS3MT 12390 (rs3740393) and 14458 (rs11191439) were consistently related to arsenic methylation regardless of the populations examined for the analysis. Thus, these SNPs may be useful indicators to predict the arsenic metabolism via methylation pathways.     

Fatigue properties of welded joints using steel with high resistance to fatigue crack growth

It has been generally recognized that the fatigue life of welded joints is little influenced by the strength of steels owing to the high-stress concentration and the tensile residual stress near the weld toe. In this paper, improvement of the fatigue life of welded joints using steel with high resistance to fatigue crack growth (ferrite/martensite (F/M) steel) is investigated. F/M steel has a microstructure with an elongated and banded martensite phase distributed in a ferrite matrix and a fatigue crack growth rate of about one-half to one-tenth in the thickness direction, compared with conventional steel. As a result, the fatigue life of an out-of-surface gusset-welded joint increases with the decrease of the fatigue crack growth rate. The fatigue life of welded joints using F/M steel with the highest resistance to fatigue crack growth increases to about twice that of joints using conventional steel. Whereas the fatigue crack growth rate decreases significantly, the fatigue life of welded joints increases only slightly. This can be attributed to the stress ratio independent of the fatigue crack growth rate. In other words, the fatigue crack growth rate of F/M steel increases with the increase of the stress ratio, approaching that of conventional steel. In the case of welded joints, even if a fatigue test is carried out at a low-stress ratio, the region near the weld toe is under a high-stress ratio due to tensile residual stress. Therefore, improvement of the fatigue life of welded joints becomes comparatively small so that the effect of fatigue crack retardation of F/M steel decreases.     

Modeling of dynamic response of ferroelectric capacitors

Abstract

A simulation model of ferroelectric capacitors which describes both hysteresis loops under arbitrary voltage profile and time dependence of polarization change is developed based on the parallel-element model. In the model, a ferroelectric capacitor is assumed to consist of parallel capacitor elements with different coercive voltage and switching polarization. A new method of pulse measurement is designed to obtain the switching behavior of individual element. The measurement on a sol-gel SrBi₂Ta₂O₉ capacitor revealed that the switching time depended on the difference between the applied voltage and the coercive voltage of the capacitor element. The switching behavior is reproduced by inserting a nonlinear resistor in series with each capacitor in the model. All the parameters used in the model are determined from the measured data and no arbitrary fitting parameters are used.     

Premartensitic anelasticity in indium-thallium alloys

The linear and nonlinear low frequency internal friction of In-24 at. pct T1 displays a Curie-Weiss type behavior in the temperature range above the transformation temperature. The critical temperature equals the martensite start temperature. It is proposed that the origin of the observed internal friction is the diffusion controlled interaction of substitutional atoms with the premartensitic strain modulation, tweed. This paper is based on a presentation made in the symposium “Pretransformation Behavior Related to Displacive Transformations in Alloys” presented at the 1986 annual AIME meeting in New Orleans, March 2–6, 1986, under the auspices of the ASM-MSD Structures Committee.     

Identification of a Triterpenoid Saponin from a Crucifer, Barbarea vulgaris, as a Feeding Deterrent to the Diamondback Moth, Plutella xylostella

Larvae of the diamondback moth, Plutella xylostella, a crucifer specialist, refuse to feed on a crucifer, Barbarea vulgaris, because of the presence of a feeding deterrent, which is extractable with chloroform. We isolated a feeding deterrent from B. vulgaris leaves, by successive fractionations with silica-gel, ODS, i.e., C₁₈ reversed phase, and Sephadex LH-20 column chromatographies, and ODS-HPLC, guided by a bioassay for feeding deterrent activity. The structure of the compound was determined to be a monodesmosidic triterpenoid saponin, 3-O-[O--D-glucopyranosyl-(14)--D-glucopyranosyl]-hederagenin, based on FAB-MS, ¹H- and ¹³C-NMR spectra, and hydrolysis experiments. When the compound was applied to cabbage leaf disks at greater than 0.18 g/mm², consumption of the disks by third instars was less than 11% of control disks treated with the solvent alone. Furthermore, all first instars died on the disks treated with the same concentrations. Because the concentration of the compound in the fresh leaves of B. vulgaris was comparable to the effective dose in the cabbage leaf disk tested, we conclude that the unacceptability of B. vulgaris to P. xylostella larvae is primarily due to this saponin.     

Genome mapping and gene analysis of Antheraea pernyi nucleopolyhedrovirus for improvement of baculovirus expression vector system

We have constructed a genome DNA map of the Antheraea pernyi nucleopolyhedrovirus (AnpeNPV) and used it to identify target genes for deletion in order to improve the newly developed baculovirus expression vector system. Initially, 50 independent PstI fragments of viral DNA were obtained by shotgun cloning, and both termini of each cloned fragment were sequenced. Then, the sequence data were used for homology search against both nucleotide and amino acid sequences of other NPVs in databases. This homology search allowed us to construct a nearly complete restriction map of a viral DNA with several assumed gaps. Four additional PstI fragments covering the gaps were obtained by PCR amplification, and a complete map of a circular viral DNA, which consisted of 54 PstI fragments, was constructed. The map indicated that the AnpeNPV genome is approximately 130.2 kbp in size and possesses high similarity to the Orgyia pseudotsugata multicapsid NPV (OpMNPV) genome in both sequence and arrangement of genes. Utilizing the genome-wide high similarity between AnpeNPV and OpMNPV, we identified two target genes on the map, namely, cathepsin and chitinase genes, whose products have been proved to be involved in the degradation of recombinant proteins and the liquefaction of virus-infected insect tissues. Comparative sequence analysis of the map also revealed the lack of certain OpMNPV open reading frame (ORF) homologs and the presence of ORFs, whose homologs do not exist in OpMNPV but in other group I NPVs, providing an insight into the position of AnpeNPV in the baculovirus phylogeny.     

Perception of complex geometric figures in chimpanzees (Pan troglodytes) and humans (Homo sapiens): Analyses of visual similarity on the basis of choice reaction time.

In a conditional-discrimination task (matching-to-sample), assessed similarities among figures consisting of 2 elemental figures through the choice reaction time (RT), nonmetric multidimensional scaling, and hierarchical cluster analysis of data from chimpanzees (Pan troglodytes) and humans (Homo sapiens). Humans also rated similarities among figures. The results of the 3 experiments clearly indicated that the RT data obtained from chimpanzees' performances were useful measures of the similarities among figures. The results suggested that chimpanzees and humans perceived the complex figures similarly. The outer-contour elements were perceived most dominantly by both species, and the straight-line elements were perceived least dominantly. Both species showed the same perceptual hierarchy or dominance among perceptual categories, as determined by the similarity of simple elements, on the basis of transformational invariances. (PsycINFO Database Record (c) 2010 APA, all rights reserved)