4,412 research outputs found
Method to obtain absolute impurity density profiles combining charge exchange and beam emission spectroscopy without absolute intensity calibration
Investigation of impurity transport properties in tokamak plasmas is essential and a diagnostic that can provide information on the impurity content is required. Combining charge exchange recombination spectroscopy (CXRS) and beam emission spectroscopy (BES), absolute radial profiles of impurity densities can be obtained from the CXRS and BES intensities, electron density and CXRS and BES emission rates, without requiring any absolute calibration of the spectra. The technique is demonstrated here with absolute impurity density radial profiles obtained in TEXTOR plasmas, using a high efficiency charge exchange spectrometer with high etendue, that measures the CXRS and BES spectra along the same lines-of-sight, offering an additional advantage for the determination of absolute impurity densities
Neurotransmitter alterations in embryonic succinate semialdehyde dehydrogenase (SSADH) deficiency suggest a heightened excitatory state during development
<p>Abstract</p> <p>Background</p> <p>SSADH (aldehyde dehydrogenase 5a1 (Aldh5a1); γ-hydroxybutyric (GHB) aciduria) deficiency is a defect of GABA degradation in which the neuromodulators GABA and GHB accumulate. The human phenotype is that of nonprogressive encephalopathy with prominent bilateral discoloration of the globi pallidi and variable seizures, the latter displayed prominently in Aldh5a1<sup>-/- </sup>mice with lethal convulsions. Metabolic studies in murine neural tissue have revealed elevated GABA [and its derivatives succinate semialdehyde (SSA), homocarnosine (HC), 4,5-dihydroxyhexanoic acid (DHHA) and guanidinobutyrate (GB)] and GHB [and its analogue D-2-hydroxyglutarate (D-2-HG)] at birth. Because of early onset seizures and the neurostructural anomalies observed in patients, we examined metabolite features during Aldh5a1<sup>-/- </sup>embryo development.</p> <p>Methods</p> <p>Embryos were obtained from pregnant dams sacrificed at E (embryo day of life) 10–13, 14–15, 16–17, 18–19 and newborn mice. Intact embryos were extracted and metabolites quantified by isotope dilution mass spectrometry (n = 5–15 subjects, Aldh5a1<sup>+/+ </sup>and Aldh5a1<sup>-/-</sup>) for each gestational age group. Data was evaluated using the <it>t </it>test and one-way ANOVA with Tukey post hoc analysis. Significance was set at the 95<sup>th </sup>centile.</p> <p>Results</p> <p>GABA and DHHA were significantly elevated at all gestational ages in Aldh5a1<sup>-/- </sup>mice, while GB was increased only late in gestation; SSA was not elevated at any time point. GHB and D-2-HG increased in an approximately linear fashion with gestational age. Correlative studies in human amniotic fluid from SSADH-deficient pregnancies (n = 5) also revealed significantly increased GABA.</p> <p>Conclusion</p> <p>Our findings indicate early GABAergic alterations in Aldh5a1<sup>-/- </sup>mice, possibly exacerbated by other metabolites, which likely induce a heightened excitatory state that may predispose neural networks to epilepsy in these animals.</p
Theory of magnetoresistance in films of dilute magnetic alloys
Earlier a magnetic anisotropy for magnetic impurities nearby the surface of
non-magnetic host was proposed in order to explain the size dependence of the
Kondo effect in dilute magnetic alloys. Recently Giordano has measured the
magnetoresistance of dilute Au(Fe) films for different thicknesses well above
the Kondo temperature . In this way he verified the existence of that
anisotropy even for such a case where the Kondo effect is not dominating. For
detailed comparison of that suggestion with experiments, the magnetic field
dependence of the magnetoresistance is calculated in the lowest approximation,
thus in the second order of the exchange coupling. The strength of the
anisotropy is very close to earlier estimates deduced from the size dependence
of the Kondo resistivity amplitude.Comment: (11 pages, 8 figures, essential changes compared to the old version
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Determining the Structure of Higgs Couplings at the LHC
Higgs boson production via weak boson fusion at the CERN Large Hadron
Collider has the capability to determine the dominant CP nature of a Higgs
boson, via the tensor structure of its coupling to weak bosons. This
information is contained in the azimuthal angle distribution of the two
outgoing forward tagging jets. The technique is independent of both the Higgs
boson mass and the observed decay channel.Comment: 5 pages, 4 figures, version accepted for publication in PR
Mapping protein interactions in the active TOM-TIM23 supercomplex
Nuclear-encoded mitochondrial proteins destined for the matrix have to be transported across two membranes. The TOM and TIM23 complexes facilitate the transport of precursor proteins with N-terminal targeting signals into the matrix. During transport, precursors are recognized by the TIM23 complex in the inner membrane for handover from the TOM complex. However, we have little knowledge on the organization of the TOM-TIM23 transition zone and on how precursor transfer between the translocases occurs. Here, we have designed a precursor protein that is stalled during matrix transport in a TOM-TIM23-spanning manner and enables purification of the translocation intermediate. Combining chemical cross-linking with mass spectrometric analyses and structural modeling allows us to map the molecular environment of the intermembrane space interface of TOM and TIM23 as well as the import motor interactions with amino acid resolution. Our analyses provide a framework for understanding presequence handover and translocation during matrix protein transport
Эффективность комплексной лучевой дифференциальной диагностики непальпируемых заболеваний молочной железы, сопровождающихся локальной тяжистой перестройкой структуры
Objective: the aim of the study was to estimate the informative value of multimodality imaging in differential diagnostics of nonpalpable breast architectural distortion of different origin.Matherials and methods. We analyzed the results of multimodality examination of 307 women with nonpalpable breast architectural distortion of different origin. They underwent mammography, handheld sonography (B-mode), compressive elastosonography, Doppler angiography, automated breast volume US-scanning, US-guided core needle biopsy (n = 115; 38%) and stereotactic core needle biopsy (n = 192; 62%), pathomorphologic analysis. Results. Breast cancer were diagnosed in 221 (72%) women, benign lesions – in 86 (28%) women. Surgical treatment was performed In 254 (83%) cases and 31 (10%) breast lesions were removed with vacuum-assisted aspiration biopsy.Conclusion. Multimodality imaging with the invasive procedures gave 92.5% sensitivity, 100% specificity, 100% showed positive prognosis, 72.5% negative prognosis, 93.1% accuracy index.Цель исследования: оценка информативности комплексной лучевой дифференциальной диагностики непальпируемых образований в виде локальной тяжистой перестройки структуры разной природы.Материал и методы. Анализу подвергнуты результаты комплексного лучевого обследования 307 больных в возрасте от 29 до 83 лет с локальной тяжистой перестройкой структуры. В комплекс входили: маммография, УЗИ в ручном В-режиме, соноэластография, допплеровское картирование, полноформатное ABVS УЗ-сканирование, трепанбиопсия под ультразвуковым (n = 115; 38%) или рентгенологическим контролем (n = 192; 62%), патоморфологическое исследование.Результаты. Рак молочной железы выявлен у 221 (72%) пациентки, заболевания доброкачественной природы – у 86 (28%). Хирургическому лечению подлежали 254 (83%) пациентки, у 31 (10%) была выполнена вакуумная аспирационная биопсия образования.Заключение. Эффективность комплексной лучевой дифференциальной диагностики заболеваний молочной железы с применением инвазивных технологий составила: чувствительность 92,5%, специфичность – 100%, точность – 93,1%, прогностическая ценность положительного результата – 100%, отрицательного результата – 72,5%
Structural insights into crista junction formation by the Mic60-Mic19 complex
Mitochondrial cristae membranes are the oxidative phosphorylation sites in cells. Crista junctions (CJs) form the highly curved neck regions of cristae and are thought to function as selective entry gates into the cristae space. Little is known about how CJs are generated and maintained. We show that the central coiled-coil (CC) domain of the mitochondrial contact site and cristae organizing system subunit Mic60 forms an elongated, bow tie–shaped tetrameric assembly. Mic19 promotes Mic60 tetramerization via a conserved interface between the Mic60 mitofilin and Mic19 CHCH (CC-helix-CC-helix) domains. Dimerization of mitofilin domains exposes a crescent-shaped membrane-binding site with convex curvature tailored to interact with the curved CJ neck. Our study suggests that the Mic60-Mic19 subcomplex traverses CJs as a molecular strut, thereby controlling CJ architecture and function
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