Photodarkening of amorphous selenium under high pressure

The photodarkening phenomena of amorphous Se have been studied by the optical absorption coefficient, sound velocity and attenuation measurements. The light illumination at low temperatures induces the photodarkening, and the photodarkened state is completely recovered by annealing near 306 K corresponding to the glass transition temperature. The photodarkening is enhanced by application of pressure. The sound velocity decreases and the sound attenuation increases by the illumination at low temperature. These suggest that a structural disorder increases in the photodarkened state. Three stages are observed for the recovery process of the photodarkened specimen. The photodarkening and the recovery process are discussed on the basis of VAP (valence alternative pair) model.<br /

Hadronic decays of B→a1(1260)b1(1235)B \to a_1(1260) b_1(1235) in the perturbative QCD approach

We calculate the branching ratios and polarization fractions of the $B \to a_1 b_1$ decays in the perturbative QCD(pQCD) approach at leading order, where $a_1$($b_1$) stands for the axial-vector $a_1(1260)[b_1(1235)]$ state. By combining the phenomenological analyses with the perturbative calculations, we find the following results: (a) the large decay rates around $10^{-5}$ to $10^{-6}$ of the $B \to a_1 b_1$ decays dominated by the longitudinal polarization(except for the $B^+ \to b_1^+ a_1^0$ mode) are predicted and basically consistent with those in the QCD factorization(QCDF) within errors, which are expected to be tested by the Large Hadron Collider and Belle-II experiments. The large $B^0 \to a_1^0 b_1^0$ branching ratio could provide hints to help explore the mechanism of the color-suppressed decays. (b) the rather different QCD behaviors between the $a_1$ and $b_1$ mesons result in the destructive(constructive) contributions in the nonfactorizable spectator diagrams with $a_1(b_1)$ emission. Therefore, an interesting pattern of the branching ratios appears for the color-suppressed $B^0 \to a_1^0 a_1^0, a_1^0 b_1^0,$ and $b_1^0 b_1^0$ modes in the pQCD approach, $Br(B^0 \to b_1^0 b_1^0) > Br(B^0 \to a_1^0 b_1^0) \gtrsim Br(B^0 \to a_1^0 a_1^0)$, which is different from $Br(B^0 \to b_1^0 b_1^0) \sim Br(B^0 \to a_1^0 b_1^0) \gtrsim Br(B^0 \to a_1^0 a_1^0)$ in the QCDF and would be verified at future experiments. (c) the large naive factorization breaking effects are observed in these $B \to a_1 b_1$ decays. Specifically, the large nonfactorizable spectator(weak annihilation) amplitudes contribute to the $B^0 \to b_1^+ a_1^-(B^+ \to a_1^+ b_1^0\; {\rm and}\; B^+ \to b_1^+ a_1^0)$ mode(s), which demand confirmations via the precise measurements.Comment: 13 pages, 1 figure, 5 tables, revtex fil

Possible mechanism for the decrease of mitochondrial aspartate aminotransferase activity in ischemic and hypoxic rat retinas

AbstractGlutamate is believed to be an excitatory amino acid neurotransmitter in the retina. Enzymes for glutamate metabolism, such as glutamate dehydrogenase, ornithine aminotransferase, glutaminase, and aspartate aminotransferase (AAT), exist mainly in the mitochondria. The abnormal increase of intracellular calcium ions in ischemic retinal cells may cause an influx of calcium ions into the mitochondria, subsequently affecting various mitochondrial enzyme activities through the activity of mitochondrial calpain. As AAT has the highest level of activity among enzymes involved in glutamate metabolism, we investigated the change of AAT activity in ischemic and hypoxic rat retinas and the protection against such activity by calpain inhibitors. We used normal RCS (rdy+/rdy+) rats. For the in vivo studies, we clamped the optic nerve of anesthetized rats to induce ischemia. In the in vitro studies, the eye cups were incubated with Locke’s solution saturated with 95% N2/5% CO2. The activity of cytosolic AAT (cAAT) was about 20% of total activity, whereas mitochondrial AAT (mAAT) was about 75% in rat retina. Ninety minutes of ischemia or hypoxia caused a 20% decrease in mAAT activity, whereas cAAT activity remained unchanged. To examine the contribution of intracellular calcium ions to the degradation of mAAT, we used Ca2+-free Locke’s solution containing 1 mM EGTA, ryanodine (Ca2+ channel blocker), and thapsigargin (Ca2+-ATPase inhibitor). In the present study, thapsigargin in Ca2+-free Locke’s solution, but not ryanodine in this solution, was found to prevent AAT degradation. AAT degradation was also prevented by calpain inhibitors (Ca2+-dependent protease inhibitor) such as calpeptin at 1 nM, 10 nM, 0.1 μM, 1 μM and 10 μM, and by calpain inhibitor peptide, but not by other protease inhibitors (10 μM leupeptin, pepstatin, chymostatin). Additionally, we determined the subcellular localization of calpain activity and examined the change of calpain activity in ischemic rat retinas. Our results suggest that decreased activity of mAAT in ischemic and hypoxic rat retinas might be evoked by the degradation by calpain-catalyzed proteolysis in mitochondria

The economic value of groundwater in Obama

AbstractStudy regionObama City has a population of 33,000 and is located in the central Wakasa district, in southwest Fukui Prefecture, Japan. Obama’s groundwater resources are supported by the Kitagawa (38km2) and Miniamigawa (17km2) river basins. Groundwater is used aboveground year round for commercial and domestic purposes and during winter months to melt snow. Submarine groundwater discharge along the coast supports a nearshore fishery in the region.Study focusResults from a choice-based analysis suggest that residents are willing to pay on average JPY 565 per month to maintain the drinking water function and aquatic resource function of groundwater in the Fukui region. However, the static approach is not appropriate for estimating the net present value of the resource, i.e., the discounted net benefit aggregated over time. We therefore develop and propose a dynamic framework capable of assessing tradeoffs between the various water uses as scarcity increases or decreases in the future.New hydrological insights for the regionMarginal willingness to pay for water in Obama is currently low because freshwater is abundant. We expect that future optimal water extraction patterns will depend most on trends in energy costs, climate change and demand growth

18-HEPE, an n-3 fatty acid metabolite released by macrophages, prevents pressure overload–induced maladaptive cardiac remodeling

N-3 polyunsaturated fatty acids (PUFAs) have potential cardiovascular benefit, although the mechanisms underlying this effect remain poorly understood. Fat-1 transgenic mice expressing Caenorhabditis elegans n-3 fatty acid desaturase, which is capable of producing n-3 PUFAs from n-6 PUFAs, exhibited resistance to pressure overload–induced inflammation and fibrosis, as well as reduced cardiac function. Lipidomic analysis revealed selective enrichment of eicosapentaenoic acid (EPA) in fat-1 transgenic bone marrow (BM) cells and EPA-metabolite 18-hydroxyeicosapentaenoic acid (18-HEPE) in fat-1 transgenic macrophages. BM transplantation experiments revealed that fat-1 transgenic BM cells, but not fat-1 transgenic cardiac cells, contributed to the antiremodeling effect and that the 18-HEPE–rich milieu in the fat-1 transgenic heart was generated by BM-derived cells, most likely macrophages. 18-HEPE inhibited macrophage-mediated proinflammatory activation of cardiac fibroblasts in culture, and in vivo administration of 18-HEPE reproduced the fat-1 mice phenotype, including resistance to pressure overload–induced maladaptive cardiac remodeling

Innovative Arbeitspolitik? Zur qualifizierten Produktionsarbeit in Japan

Die vorwiegend industriesoziologisch und ökonomisch ausgerichtete Studie untersucht am Beispiel der Schaufelfertigung im Turbinenbau, inwieweit sich in Japan tatsächlich die oft zitierten innovativen, nichttayloristischen Arbeitsformen auf Mikroebene im Bereich der Einzelfertigung nachweisen lassen. Dazu führten die Autoren zwischen Mai 1994 und November 1996 leitfadengestützte Expertengespräche mit über 60 Personen, machten Betriebsbegehungen und werteten neben der einschlägigen Literatur zusätzlich betriebliches Material aus. Nach der Darstellung der Situation in der Turbinenindustrie und der Beschreibung der Fertigungsprozesse, Arbeitsorganisation und der hierarchischen Strukturen in den betrachteten Unternehmen untersuchen die Autoren folgende Aspekte der Arbeitspolitik: Personalbeschaffung und -qualifizierung, Arbeitsteilung und -einsatz, Qualitätssicherung, Personalbewertung und Aufstiegswege. Deutlich wird dabei, daß sich in den betrachteten Unternehmen keineswegs innovative Formen der Arbeitsorganisation nachweisen lassen. Vielmehr dominieren hochgradig arbeitsteilige, konventionell-tayloristische Formen. (ZPol, NOMOS

<ORIGINAL REPORT>X-ray scanning analytical microscopic and scanning electron microscopic studies of an unusual case of dens invaginatus

A mass was extirpated from the region of the maxillary right third molar of a 20 year-old patient. It was proved to be an extreme and unerupted case of dens invaginatus. The clinical and histopathological features have been presented in a previous paper. Ameloblasts and odontoblasts were noted along the surface of enamel or dentin. In the present study, X-ray scanning analytical microscopy (XSAM), a newly developed technique, together with scanning electron microscopy (SEM) was applied for the study of this malformed tooth. SEM study showed a strange arrangement of well-formed enamel and dentin in normal structures. The distribution of calcium (Ca) and phosphorus (P) was clearly observed by the XSAM method. It revealed that the bulk of dentin was composed of two kinds of dentin quite different in mineral content while their SEM appearances were similar. The part of the dentin near the dentinoenamel junction had much higher Ca and P concentrations than the outer parts. In conclusion, the disagreement between the microscopic findings and the XSAM findings suggests the importance of applying various methods in studies to obtain a comprehensive understanding of such malformation. In addition, the present investigation also points out the complexity of the disturbance ranging within the term dens invaginatus