729 research outputs found

    Defects in ZnO nanoparticles laser-ablated in water-ethanol mixtures at different pressures

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    The effect of liquid medium and its pressure on the photoluminescence of ZnO nanoparticles prepared via laser ablation of Zn targets in various water-ethanol mixtures is studied. As the ethanol content increases, the photoluminescence of the product changes, while metallic zinc is observed to emerge in nanomaterials prepared in ethanol-rich environments. The applied pressure had a less profound effect, mainly affecting materials produced in water or water-ethanol, and much less those generated in pressurized ethanol. Tuning the reactivity of the liquid and pressurizing it during laser ablation is demonstrated to be promising for tailoring the emission properties of the product

    Muon Spin Relaxation Studies of Magnetic-Field-Induced Effects in High-TcT_{c} Superconductors

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    Muon spin relaxation (μ\muSR) measurements in high transverse magnetic fields (c^\parallel \hat c) revealed strong field-induced quasi-static magnetism in the underdoped and Eu doped (La,Sr)2_{2}CuO4_{4} and La1.875_{1.875}Ba0.125_{0.125}CuO4_{4}, existing well above TcT_{c} and TNT_{N}. The susceptibility-counterpart of Cu spin polarization, derived from the muon spin relaxation rate, exhibits a divergent behavior towards T25T \sim 25 K. No field-induced magnetism was detected in overdoped La1.81_{1.81}Sr0.19_{0.19}CuO4_{4}, optimally doped Bi2212, and Zn-doped YBa2_{2}Cu3_{3}O7_{7}.Comment: 4 pages, 4 color figure

    The breast feeding mother and xenon anaesthesia: four case reports. Breast feeding and xenon anaesthesia

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    <p>Abstract</p> <p>Background</p> <p>Four nursing mothers consented to anaesthesia for urgent surgery only on condition that their ability to breast feed would not be impaired.</p> <p>Methods</p> <p>Following induction of general anaesthesia with propofol and remifentanil, 65-69% xenon supplemented with remifentanil was used as an inhalational anaesthetic for maintenance.</p> <p>Results</p> <p>After finishing surgery the women could be extubated between 2:52 and 7:22 minutes. The women were fully alert just minutes after extubation and spent about 45 minutes in the recovery room before discharge to a regular ward. They resumed regular breast feeding some time later. The propofol concentration in the blood was measured after 0, 30, 90, and 300 minutes and in the milk after 90 and 300 minutes. Just 90 minutes after extubation, the concentration of propofol in the milk was limited (> 3 mg/l) so that pharmacological effects on the babies were excluded after oral intake. Also, no traces of xenon gas were found in the maternal milk at any time. After propofol induction and maintenance of anaesthesia with xenon in combination with a water-soluble short-acting drug like remifentanil, the concentration of propofol in maternal milk is low (> 3 mg/l 90 min after anesthesia) and harmless after oral intake.</p> <p>Conclusions</p> <p>These results, as well as the rapid elimination and absence of metabolism of xenon, are of great interest to nursing mothers. General anaesthesia with propofol for induction only, combined with remifentanil and xenon for maintenance, has not yet been described in breast feeding mothers.</p

    Associations of a PTPN11 G/A polymorphism at intron 3 with Helicobactor pylori seropositivity, gastric atrophy and gastric cancer in Japanese

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    <p>Abstract</p> <p>Background</p> <p>Previous studies have revealed the significance of <it>Helicobacter pylori </it>(<it>H. pylori</it>) infection as a risk factor of gastric cancer. Cytotoxin-associated gene A (<it>cagA</it>) positivity has been demonstrated to determine the clinical outcome of <it>H. pylori </it>infection in the presence of SHP-2 (src homology 2 domain-containing protein tyrosine phosphatase-2). This study aimed to examine the formerly reported association of G/A <it>PTPN11 (protein-tyrosine phosphatase, nonreceptor-type 11) </it>polymorphism (rs2301756) with gastric atrophy, as well as the association with gastric cancer in a Japanese population using a large sample size.</p> <p>Methods</p> <p>Study subjects were 583 histologically diagnosed patients with gastric cancer (429 males and 154 females) and age- and sex-frequency-matched 1,636 non-cancer outpatients (1,203 males and 433 females), who visited Aichi Cancer Center Hospital between 2001–2005. Serum anti-<it>H. pylori </it>IgG antibody and pepsinogens were measured to evaluate <it>H. pylori </it>infection and gastric atrophy, respectively. Odds ratios (ORs) and 95% confidence intervals (CIs) were calculated by a logistic model.</p> <p>Results</p> <p>Among <it>H. pylori </it>seropositive non-cancer outpatients, the age- and sex-adjusted OR of gastric atrophy was 0.82 (95% CI 0.62–1.10, <it>P </it>= 0.194) for <it>G/A</it>, 0.84 (95% CI 0.39–1.81, <it>P </it>= 0.650) for <it>A/A</it>, and 0.83 (95% CI 0.62–1.09, <it>P </it>= 0.182) for <it>G/A</it>+<it>A/A</it>, relative to <it>G/G </it>genotype, and that of severe gastric atrophy was 0.70 (95% CI 0.47–1.04, <it>P </it>= 0.079), 0.56 (95% CI 0.17–1.91, <it>P </it>= 0.356), and 0.68 (95% CI 0.46–1.01, <it>P </it>= 0.057), respectively. Among <it>H. pylori </it>infected subjects (<it>H. pylori </it>seropositive subjects and seronegative subjects with gastric atrophy), the adjusted OR of severe gastric atrophy was further reduced; 0.62 (95% CI 0.42–0.90, <it>P </it>= 0.012) for <it>G/A</it>+<it>A/A</it>. The distribution of the genotype in patients with gastric cancer was not significantly different from that for <it>H. pylori </it>infected subjects without gastric atrophy.</p> <p>Conclusion</p> <p>Our study results revealed that those with the <it>A/A </it>genotype of <it>PTPN11 </it>rs2301756 polymorphism are at lower risk of severe gastric atrophy, but are not associated with a decreased risk of gastric cancer, which partially supported our previous finding that the polymorphism in the <it>PTPN11 </it>gene encoding SHP-2 was associated with the gastric atrophy risk in <it>H. pylori </it>infected Japanese. The biological roles of this <it>PTPN11 </it>polymorphism require further investigation.</p

    Left−Right Asymmetry Defect in the Hippocampal Circuitry Impairs Spatial Learning and Working Memory in iv Mice

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    Although left-right (L−R) asymmetry is a fundamental feature of higher-order brain function, little is known about how asymmetry defects of the brain affect animal behavior. Previously, we identified structural and functional asymmetries in the circuitry of the mouse hippocampus resulting from the asymmetrical distribution of NMDA receptor GluR ε2 (NR2B) subunits. We further examined the ε2 asymmetry in the inversus viscerum (iv) mouse, which has randomized laterality of internal organs, and found that the iv mouse hippocampus exhibits right isomerism (bilateral right-sidedness) in the synaptic distribution of theε2 subunit, irrespective of the laterality of visceral organs. To investigate the effects of hippocampal laterality defects on higher-order brain functions, we examined the capacity of reference and working memories of iv mice using a dry maze and a delayed nonmatching-to-position (DNMTP) task, respectively. The iv mice improved dry maze performance more slowly than control mice during acquisition, whereas the asymptotic level of performance was similar between the two groups. In the DNMTP task, the iv mice showed poorer accuracy than control mice as the retention interval became longer. These results suggest that the L−R asymmetry of hippocampal circuitry is critical for the acquisition of reference memory and the retention of working memory
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