953 research outputs found

    Dielectric anomaly in coupled rotor systems

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    The correlated dynamics of coupled quantum rotors carrying electric dipole moment is theoretically investigated. The energy spectra of coupled rotors as a function of dipolar interaction energy is analytically solved. The calculated dielectric susceptibilities of the system show the peculiar temperature dependence different from that of isolated rotors.Comment: 5 pages, 4 figures (Figure 2 is available on request from [email protected]

    Conduction of activity between muscles in the terminal region of the common bile duct and in the neighboring duodenum

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    The relationship between muscle activity at the terminal region of the common bile duct and the duodenal muscle was examined in rabbits. The rhythmic muscle activity in the terminal region was synchronous with duodenal muscle activity. The activity of the latter muscle preceded the former. The activity at the terminal region synchronous with the rhythmic activity of the duodenal muscle sometimes disappeared spontaneously. The muscle activity of the ampulla and the spincter at the terminal region was sometimes independently lost. The conduction of excitation from the duodenal muscle to the terminal region appeared to be performed at several sites. The existence of a &#34;conduction-shunt path&#34; between the terminal region and the duodenum, as well as between the ampulla and the sphincter appeared probably. Some quantitative differences were found between the spincter, ampulla and duodenum in inhibitory effects to stimulation of splanchnic nerves and reflex effects and to excitatory effects of cholecystokinin-pancreoxymin and caerulein. These results seem to indicate that the sympathetic nerves and the intramural cholinergic neurones controlling these region carry out activities quantitatively different from each other.</p

    Numerical study on mixing of sprayed liquid in an LNG storage tank

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    This paper presents a numerical method to simulate the mixing of heavier LNG sprayed on lighter layer. Numerical results for evolutions of flow field and density field are obtained in a rectangular computational domain which includes the vicinity of the liquid surface. At the surface boundary, uniform distributions of the fluid velocity and the density are assumed. Detail structure of flow caused by impingements of liquid drops are neglected. But, to trigger a realistic motion, a series of random numbers is employed. It is used as an initial distribution of the density near the surface. This method successfully gives a realistic simulation of the mixing process. Numerical results for mixing velocity shows good agreement with experimental data

    Mechanisms of Membrane Curvature Generation in Membrane Traffic

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    During the vesicular trafficking process, cellular membranes undergo dynamic morphological changes, in particular at the vesicle generation and fusion steps. Changes in membrane shape are regulated by small GTPases, coat proteins and other accessory proteins, such as BAR domain-containing proteins. In addition, membrane deformation entails changes in the lipid composition as well as asymmetric distribution of lipids over the two leaflets of the membrane bilayer. Given that P4-ATPases, which catalyze unidirectional flipping of lipid molecules from the exoplasmic to the cytoplasmic leaflets of the bilayer, are crucial for the trafficking of proteins in the secretory and endocytic pathways, changes in the lipid composition are involved in the vesicular trafficking process. Membrane remodeling is under complex regulation that involves the composition and distribution of lipids as well as assembly of proteins

    Risk Factors for Nosocomial Infection in the Neonatal Intensive Care Unit by the Japanese Nosocomial Infection Surveillance (JANIS)

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    We evaluated the infection risks in the neonatal intensive care unit (NICU) using data of NICU infection surveillance data. The subjects were 871 NICU babies, consisting of 465 boys and 406 girls, who were cared for between June 2002 and January 2003 in 7 medical institutions that employed NICU infection surveillance. Infections were defined according to the National Nosocomial Infection Surveillance (NNIS) System. Of the 58 babies with nosocomial infections, 15 had methicillin-resistant Staphylococcus aureus (MRSA) infection. Multiple logistic regression analysis demonstrated that the odds ratio for nosocomial infections was significantly related to gender, birth weight and the insertion of a central venous catheter (CVC). When the birth weight group of more than 1, 500g was regarded as the reference, the odds ratio was 2.35 in the birth weight group of 1,000-1,499g and 8.82 in the birth weight group of less than 1,000g. The odds ratio of the CVC () for nosocomial infection was 2.27. However, other devices including artificial ventilation, umbilical artery catheter, umbilical venous catheter, and urinary catheter were not significant risk factors. The incidence of MRSA infection rapidly increased from 0.3% in the birth weight group of more than 1,500g to 2.1% in the birth weight group of 1,000-1,499g, and to 11.1% in the birth weight group of less than 1,000g. When the birth weight group of more than 1,500g was regarded as the reference, multiple logistic regression analysis demonstrated that the odds ratio was 7.25 in the birth weight group of 1,000-1,499g and 42.88 in the birth weight group of less than 1,000g. These odds ratios were significantly higher than that in the reference group. However, the application of devices did not cause any significant differences in the odds ratio for MRSA infection.</p

    Orienting coupled quantum rotors by ultrashort laser pulses

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    We point out that the non-adiabatic orientation of quantum rotors, produced by ultrashort laser pulses, is remarkably enhanced by introducing dipolar interaction between the rotors. This enhanced orientation of quantum rotors is in contrast with the behavior of classical paired rotors, in which dipolar interactions prevent the orientation of the rotors. We demonstrate also that a specially designed sequence of pulses can most efficiently enhances the orientation of quantum paired rotors.Comment: 7 pages, 5 figures, to appear in Phys. Rev.

    ATPase reaction cycle of P4-ATPases affects their transport from the endoplasmic reticulum

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    P4‐ATPases belonging to the P‐type ATPase superfamily mediate active transport of phospholipids across cellular membranes. Most P4‐ATPases, except ATP9A and ATP9B proteins, form heteromeric complexes with CDC50 proteins, which are required for transport of P4‐ATPases from the endoplasmic reticulum (ER) to their final destinations. P‐type ATPases form autophosphorylated intermediates during the ATPase reaction cycle. However, the association of the catalytic cycle of P4‐ATPases with their transport from the ER and their cellular localization has not been studied. Here, we show that transport of ATP9 and ATP11 proteins as well as that of ATP10A from the ER depends on the ATPase catalytic cycle, suggesting that conformational changes in P4‐ATPases during the catalytic cycle are crucial for their transport from the ER
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