827 research outputs found

    Recent advances in deuterium permeation induced transmutation experiments using nano-structured Pd/CaO/Pd multilayer thin film

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    Permeation induced transmutation reactions, which we originally found in the nanostructured Pd multilayer film composed of Pd and CaO thin film and Pd substrate, have been observed in our laboratory and other research institutes. Recently, Toyota R&D centre reported almost complete replication experiments on the transmutation of Cs into Pr at ICCF-17. We observed transmutation reactions of Cs into Pr, Ba into Sm, W into Pt up to now. Especially, transmutation of Cs into Pr has been confirmed by "in-situ" measurements using x-ray fluorescence spectrometry (XRF) at SPring-8 in Japan. Experimental data that indicates the presence of transmutation have been accumulated and the underlying mechanism for inducing low energy transmutation reactions is gradually becoming clear, although systematic experimental study is still insufficient. The permeation induced transmutation technology would be expected as an innovative nuclear transmutation method for radioactive waste and a new energy source if we would be able to increase the amount of transmutation products. We have been trying to increase the amount of transmutation products these years for the practical application. The following factors are assumed to be important for inducing deuterium permeation transmutation. 1) Local Deuteron Density 2) Electronic Structure Based on this assumption, we applied an electrochemical method to increase the local deuteron density near the surface of the nano-structured Pd multilayer film. We also tried to increase the transmutation products by changing surface electronic state. These recent experimental methods gave us increased transmutation products, gamma-ray emissions, and new implications on Deuterium Permeation Induced Transmutation

    Measurement of the electron transmission rate of the gating foil for the TPC of the ILC experiment

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    We have developed a gating foil for the time projection chamber envisaged as a central tracker for the international linear collider experiment. It has a structure similar to the Gas Electron Multiplier (GEM) with a higher optical aperture ratio and functions as an ion gate without gas amplification. The transmission rate for electrons was measured in a counting mode for a wide range of the voltages applied across the foil using an 55^{55}Fe source and a laser in the absence of a magnetic field. The blocking power of the foil against positive ions was estimated from the electron transmissions.Comment: 25 pages containing 14 figures and 1 tabl

    Effects of MDMA on Extracellular Dopamine and Serotonin Levels in Mice Lacking Dopamine and/or Serotonin Transporters

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    3,4-Methylendioxymethamphetamine (MDMA) has both stimulatory and hallucinogenic properties which make its psychoactive effects unique and different from those of typical psychostimulant and hallucinogenic agents. The present study investigated the effects of MDMA on extracellular dopamine (DAex) and serotonin (5-HTex) levels in the striatum and prefrontal cortex (PFC) using in vivo microdialysis techniques in mice lacking DA transporters (DAT) and/or 5-HT transporters (SERT). subcutaneous injection of MDMA (3, 10 mg/kg) significantly increased striatal DAex in wild-type mice, SERT knockout mice, and DAT knockout mice, but not in DAT/SERT double-knockout mice. The MDMA-induced increase in striatal DAex in SERT knockout mice was significantly less than in wildtype mice. In the PFC, MDMA dose-dependently increased DAex levels in wildtype, DAT knockout, SERT knockout and DAT/SERT double-knockout mice to a similar extent. In contrast, MDMA markedly increased 5-HTex in wildtype and DAT knockout mice and slightly increased 5-HTex in SERT-KO and DAT/SERT double-knockout mice. The results confirm that MDMA acts at both DAT and SERT and increases DAex and 5-HTex

    Interhemispheric Interactions between the Human Primary Somatosensory Cortices

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    In the somatosensory domain it is still unclear at which processing stage information reaches the opposite hemispheres. Due to dense transcallosal connections, the secondary somatosensory cortex (S2) has been proposed to be the key candidate for interhemispheric information transfer. However, recent animal studies showed that the primary somatosensory cortex (S1) might as well account for interhemispheric information transfer. Using paired median nerve somatosensory evoked potential recordings in humans we tested the hypothesis that interhemispheric inhibitory interactions in the somatosensory system occur already in an early cortical processing stage such as S1. Conditioning right S1 by electrical median nerve (MN) stimulation of the left MN (CS) resulted in a significant reduction of the N20 response in the target (left) S1 relative to a test stimulus (TS) to the right MN alone when the interstimulus interval between CS and TS was between 20 and 25 ms. No such changes were observed for later cortical components such as the N20/P25, N30, P40 and N60 amplitude. Additionally, the subcortically generated P14 response in left S1 was also not affected. These results document the existence of interhemispheric inhibitory interactions between S1 in human subjects in the critical time interval of 20–25 ms after median nerve stimulation

    Parathyroid hormone related peptide and receptor expression in paired primary prostate cancer and bone metastases

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    Parathyroid hormone-related peptide is a regulatory protein implicated in the pathogenesis of bone metastases, particularly in breast carcinoma. Parathyroid hormone-related peptide is widely expressed in primary prostate cancers but there are few reports of its expression in prostatic metastases. The aim of this study was to examine the expression of parathyroid hormone-related peptide and its receptor in matched primary and in bone metastatic tissue from patients with untreated adenocarcinoma of the prostate. Eight-millimetre trephine iliac crest bone biopsies containing metastatic prostate cancer were obtained from 14 patients from whom matched primary tumour tissue was also available. Histological grading was performed by an independent pathologist. The cellular location of mRNA for parathyroid hormone-related peptide and parathyroid hormone-related peptide receptor was identified using in situ hybridization with 35S-labelled probe. Expression of parathyroid hormone-related peptide and its receptor was described as uniform, heterogenous or negative within the tumour cell population. Parathyroid hormone-related peptide expression was positive in 13 out of 14 primary tumours and in all 14 metastases. Receptor expression was evident in all 14 primaries and 12 out of 14 metastases. Co-expression of parathyroid hormone-related peptide and parathyroid hormone-related peptide receptor was common (13 primary tumours, 12 metastases). The co-expression of parathyroid hormone-related peptide and its receptor suggest that autocrine parathyroid hormone-related peptide mediated stimulation may be a mechanism of escape from normal growth regulatory pathways. The high frequency of parathyroid hormone-related peptide expression in metastases is consistent with a role in the pathogenesis of bone metastases
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