492 research outputs found

    Electronic structure and spectroscopy of the quaternary Heusler alloy Co2_2Cr1x_{1-x}Fex_{x}Al

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    Quaternary Heusler alloys Co2_2Cr1x_{1-x}Fex_{x}Al with varying Cr to Fe ratio xx were investigated experimentally and theoretically. The electronic structure and spectroscopic properties were calculated using the full relativistic Korringa-Kohn-Rostocker method with coherent potential approximation to account for the random distribution of Cr and Fe atoms as well as random disorder. Magnetic effects are included by the use of spin dependent potentials in the local spin density approximation. Magnetic circular dichroism in X-ray absorption was measured at the L2,3L_{2,3} edges of Co, Fe, and Cr of the pure compounds and the x=0.4x=0.4 alloy in order to determine element specific magnetic moments. Calculations and measurements show an increase of the magnetic moments with increasing iron content. Resonant (560eV - 800eV) soft X-ray as well as high resolution - high energy (3.5\geq 3.5keV) hard X-ray photo emission was used to probe the density of the occupied states in Co2_2Cr0.6_{0.6}Fe0.4_{0.4}Al.Comment: J.Phys.D_Appl.Phys. accepte

    Characterization of recombinant β-fructofuranosidase from Bifidobacterium adolescentis G1

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    <p>Abstract</p> <p>Background</p> <p>We have previously reported on purification and characterization of β-fructofuranosidase (β-FFase) from <it>Bifidobacterium adolescentis </it>G1. This enzyme showed high activity of hydrolysis on fructo-oligosaccharides with a low degree of polymerization. Recently, genome sequences of <it>B. longum </it>NCC2705 and <it>B. adolescentis </it>ATCC 15703 were determined, and <it>cscA </it>gene in the both genome sequences encoding β-FFase was predicted. Here, cloning of <it>cscA </it>gene encoding putative β-FFase from <it>B. adolescentis </it>G1, its expression in <it>E. coli </it>and properties of the recombinant protein are described.</p> <p>Results</p> <p>Using the information of <it>cscA </it>gene from <it>Bifidobacterium adolescentis </it>ATCC 15703, <it>cscA </it>gene from <it>B. adolescentis </it>G1 was cloned and sequenced. The N-terminal amino acid sequence of purified β-FFase from <it>B. adolescentis </it>G1 was identical to the deduced amino acid sequences of <it>cscA </it>gene from <it>B. adolescentis </it>G1. To confirm the translated product of the <it>cscA </it>gene, the recombinant protein was expressed in <it>Escherichia coli</it>. Molecular mass of the purified recombinant enzyme was estimated to be about 66,000 by SDS-PAGE and 60,300 by MALDI TOF-MS. The optimum pH of the enzyme was 5.7 and the enzyme was stable at pH 5.0-8.6. The thermostability of the enzyme was up to 50°C. The <it>K</it><sub>m </sub>(mM), <it>V</it><sub>max </sub>(μmol/mg of protein/min), <it>k</it><sub>0 </sub>(sec<sup>-1</sup>) and <it>k</it><sub>0</sub>/<it>K</it><sub>m</sub>(mM<sup>-1 </sup>sec<sup>-1</sup>) for 1-kestose, neokestose, nystose, fructosylnystose, sucrose and inulin were 1.7, 107, 107.5, 63.2, and 1.7, 142, 142.7, 83.9, and 3.9, 152, 152.8, 39.2, and 2.2, 75, 75.4, 34.3, and 38, 79, 79.4, 2.1, and 25.9, 77, 77.4, 3.0, respectively. The hydrolytic activity was strongly inhibited by AgNO<sub>3</sub>, SDS, and HgCl<sub>2</sub>.</p> <p>Conclusion</p> <p>The recombinant enzyme had similar specificity to the native enzyme, high affinity for 1-kestose, and low affinity for sucrose and inulin, although properties of the recombinant enzyme showed slight difference from those of the native one previously described.</p

    Efficacy of a hybrid assistive limb in post-stroke hemiplegic patients: a preliminary report

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    <p>Abstract</p> <p>Background</p> <p>Robotic devices are expected to be widely used in various applications including support for the independent mobility of the elderly with muscle weakness and people with impaired motor function as well as support for nursing care that involves heavy laborious work. We evaluated the effects of a hybrid assistive limb robot suit on the gait of stroke patients undergoing rehabilitation.</p> <p>Methods</p> <p>The study group comprised 16 stroke patients with severe hemiplegia. All patients underwent gait training. Four patients required assistance, and 12 needed supervision while walking. The stride length, walking speed and physiological cost index on wearing the hybrid assistive limb suit and a knee-ankle-foot orthosis were compared.</p> <p>Results</p> <p>The hybrid assistive limb suit increased the stride length and walking speed in 4 of 16 patients. The patients whose walking speed decreased on wearing the hybrid assistive limb suit either had not received sufficient gait training or had an established gait pattern with a knee-ankle-foot orthosis using a quad cane. The physiological cost index increased after wearing the hybrid assistive limb suit in 12 patients, but removal of the suit led to a decrease in the physiological cost index values to equivalent levels prior to the use of the suit.</p> <p>Conclusions</p> <p>Although the hybrid assistive limb suit is not useful for all hemiplegic patients, it may increase the walking speed and affect the walking ability. Further investigation would clarify its indication for the possibility of gait training.</p

    Biomarkers of clinical benefit for anti-epidermal growth factor receptor agents in patients with non-small-cell lung cancer

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    Non-small-cell lung cancer (NSCLC) remains by far the major cause of cancer-related death in the Western world in both men and women. The majority of patients will be diagnosed with metastatic disease, and chemotherapy doublets remain the cornerstone of treatment for these patients. However, chemotherapy has a minimal impact on long-term survival and prognosis remains poor for these patients. Further improvement in treatment is likely to require incorporation of novel targeted therapies. Among these agents, inhibitors of the epidermal growth factor receptor (EGFR) have demonstrated significant activity in the first-, second- or third-line treatment of NSCLC. The purpose of current paper is to present the evidence for using several proposed molecular biomarkers as a tool for selection of NSCLC patients for anti-EGFR treatment. According to current data, EGFR mutation status appears to be the strongest predictor for the selection of NSCLC patients to first-line treatment with EGFR tyrosine kinase inhibitors vs chemotherapy. Use of other biomarkers remains investigational

    Short-term effects of amelogenin gene splice products A+4 and A-4 implanted in the exposed rat molar pulp

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    In order to study the short-time effects of two bioactive low-molecular amelogenins A+4 and A-4, half-moon cavities were prepared in the mesial aspect of the first maxillary molars, and after pulp exposure, agarose beads alone (controls) or beads soaked in A+4 or A-4 (experimental) were implanted into the pulp. After 1, 3 or 7 days, the rats were killed and the teeth studied by immunohistochemistry. Cell proliferation was studied by PCNA labeling, positive at 3 days, but decreasing at day 7 for A+4, whilst constantly high between 3 and 7 days for A-4. The differentiation toward the osteo/odontoblast lineage shown by RP59 labeling was more apparent for A-4 compared with A+4. Osteopontin-positive cells were alike at days 3 and 7 for A-4. In contrast, for A+4, the weak labeling detected at day 3 became stronger at day 7. Dentin sialoprotein (DSP), an in vivo odontoblast marker, was not detectable until day 7 where a few cells became DSP positive after A-4 stimulation, but not for A+4. These results suggest that A +/- 4 promote the proliferation of some pulp cells. Some of them further differentiate into osteoblast-like progenitors, the effects being more precocious for A-4 (day 3) compared with A+4 (day 7). The present data suggest that A +/- 4 promote early recruitment of osteogenic progenitors, and evidence functional differences between A+4 and A-4

    Defects in muscarinic receptor-coupled signal transduction in isolated parotid gland cells after in vivo irradiation: evidence for a non-DNA target of radiation

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    Radiation-induced dysfunction of normal tissue, an unwanted side effect of radiotherapeutic treatment of cancer, is usually considered to be caused by impaired loss of cell renewal due to sterilisation of stem cells. This implies that the onset of normal tissue damage is usually determined by tissue turnover rate. Salivary glands are a clear exception to this rule: they have slow turnover rates (>60 days), yet develop radiation-induced dysfunction within hours to days. We showed that this could not be explained by a hypersensitivity to radiation-induced apoptosis or necrosis of the differentiated cells. In fact, salivary cells are still capable of amylase secretion shortly after irradiation while at the same time water secretion seems specifically and severely impaired. Here, we demonstrate that salivary gland cells isolated after in vivo irradiation are impaired in their ability to mobilise calcium from intracellular stores (Ca2+i), the driving force for water secretion, after exposure to muscarinic acetylcholine receptor agonists. Using radioligand-receptor-binding assays it is shown that radiation caused no changes in receptor density, receptor affinity nor in receptor-G-protein coupling. However, muscarinic acetylcholine agonist-induced activation of protein kinase C alpha (PKCα), measured as translocation to the plasma membrane, was severely affected in irradiated cells. Also, the phorbol ester PMA could no longer induce PKCα translocation in irradiated cells. Our data hence indicate that irradiation specifically interferes with PKCα association with membranes, leading to impairment of intracellular signalling. To the best of our knowledge, these data for the first time suggest that, the cells' capacity to respond to a receptor agonist is impaired after irradiation

    Search for direct production of charginos and neutralinos in events with three leptons and missing transverse momentum in √s = 7 TeV pp collisions with the ATLAS detector

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    A search for the direct production of charginos and neutralinos in final states with three electrons or muons and missing transverse momentum is presented. The analysis is based on 4.7 fb−1 of proton–proton collision data delivered by the Large Hadron Collider and recorded with the ATLAS detector. Observations are consistent with Standard Model expectations in three signal regions that are either depleted or enriched in Z-boson decays. Upper limits at 95% confidence level are set in R-parity conserving phenomenological minimal supersymmetric models and in simplified models, significantly extending previous results

    Single hadron response measurement and calorimeter jet energy scale uncertainty with the ATLAS detector at the LHC

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    The uncertainty on the calorimeter energy response to jets of particles is derived for the ATLAS experiment at the Large Hadron Collider (LHC). First, the calorimeter response to single isolated charged hadrons is measured and compared to the Monte Carlo simulation using proton-proton collisions at centre-of-mass energies of sqrt(s) = 900 GeV and 7 TeV collected during 2009 and 2010. Then, using the decay of K_s and Lambda particles, the calorimeter response to specific types of particles (positively and negatively charged pions, protons, and anti-protons) is measured and compared to the Monte Carlo predictions. Finally, the jet energy scale uncertainty is determined by propagating the response uncertainty for single charged and neutral particles to jets. The response uncertainty is 2-5% for central isolated hadrons and 1-3% for the final calorimeter jet energy scale.Comment: 24 pages plus author list (36 pages total), 23 figures, 1 table, submitted to European Physical Journal

    Measurements of fiducial and differential cross sections for Higgs boson production in the diphoton decay channel at s√=8 TeV with ATLAS

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    Measurements of fiducial and differential cross sections are presented for Higgs boson production in proton-proton collisions at a centre-of-mass energy of s√=8 TeV. The analysis is performed in the H → γγ decay channel using 20.3 fb−1 of data recorded by the ATLAS experiment at the CERN Large Hadron Collider. The signal is extracted using a fit to the diphoton invariant mass spectrum assuming that the width of the resonance is much smaller than the experimental resolution. The signal yields are corrected for the effects of detector inefficiency and resolution. The pp → H → γγ fiducial cross section is measured to be 43.2 ±9.4(stat.) − 2.9 + 3.2 (syst.) ±1.2(lumi)fb for a Higgs boson of mass 125.4GeV decaying to two isolated photons that have transverse momentum greater than 35% and 25% of the diphoton invariant mass and each with absolute pseudorapidity less than 2.37. Four additional fiducial cross sections and two cross-section limits are presented in phase space regions that test the theoretical modelling of different Higgs boson production mechanisms, or are sensitive to physics beyond the Standard Model. Differential cross sections are also presented, as a function of variables related to the diphoton kinematics and the jet activity produced in the Higgs boson events. The observed spectra are statistically limited but broadly in line with the theoretical expectations
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