816 research outputs found
Changes in glial gene expression in the prefrontal cortex in relation to major depressive disorder, suicide and psychotic features
Changes in glial gene expression in the prefrontal cortex in relation to major depressive disorder, suicide and psychotic features
BACKGROUND: To establish whether major depressive disorder (MDD), suicidal behaviors and psychotic features contribute to glial alterations in the human prefrontal cortex. MATERIALS AND METHODS: We compared mRNA expression using real-time qPCR of 17 glia related genes in the dorsolateral prefrontal cortex (DLPFC) and the anterior cingulate cortex (ACC) between 24 patients with MDD and 12 well-matched controls without psychiatric or neurological diseases. The MDD group was subdivided into i) MDD who died of suicide (MDD-S) or natural causes (MDD-NS) and ii) MDD with or without psychotic features (MDD-P and MDD-NP). The results were followed up with confounder factor analysis. RESULTS: Astrocyte gene aldehyde dehydrogenase-1 L1 (ALDH1L1) showed an increased expression in the DLPFC of MDD-NS and the ACC of MDD-NP. S100 calcium-binding protein B (S100B) was upregulated in the DLPFC of MDD compared to the controls. Microglial markers CD11B and purinergic receptor 12 (P2RY12) both showed decreased expression in the ACC of MDD-NS. CD68 was increased in the DLPFC of MDD in both, MDD-S and MDD-P, compared to the controls. In addition, there was increased translocator protein (TSPO) expression in the DLPFC of MDD, especially MDD-NS. In the ACC, this gene had a lower expression in MDD-P than in MDD-NP. Myelin basic protein (MBP) mRNA in the DLPFC increased in MDD, in relation to psychotic features, but not to suicide. LIMITATIONS: Sample volumes are relatively small. CONCLUSIONS: Different glial functions in MDD were related to specific brain area, suicide or psychotic features
An Asymmetric Cone Model for Halo Coronal Mass Ejections
Due to projection effects, coronagraphic observations cannot uniquely
determine parameters relevant to the geoeffectiveness of CMEs, such as the true
propagation speed, width, or source location. The Cone Model for Coronal Mass
Ejections (CMEs) has been studied in this respect and it could be used to
obtain these parameters. There are evidences that some CMEs initiate from a
flux-rope topology. It seems that these CMEs should be elongated along the
flux-rope axis and the cross section of the cone base should be rather
elliptical than circular. In the present paper we applied an asymmetric cone
model to get the real space parameters of frontsided halo CMEs (HCMEs) recorded
by SOHO/LASCO coronagraphs in 2002. The cone model parameters are generated
through a fitting procedure to the projected speeds measured at different
position angles on the plane of the sky. We consider models with the apex of
the cone located at the center and surface of the Sun. The results are compared
to the standard symmetric cone model
Ideal stoichiometric technetium nitrides under pressure: a first-principles study
Technetium nitrides with various ideal stoichiometries have been investigated with the first-principle method at the pressures between 0–60 GPa. It have been found that there could be many stable technetium nitrides including Tc₃N, Tc₂N, TcN, Tc₂N₃, TcN₂, TcN₃, and TcN₄, among which Tc₃N and Tc₂N sub-nitrides are synthesizable at zero pressure and could be applied to nuclear waste management, such as separate radioactive 99Tc from nuclear fuel cycle. Moreover, N-rich TcN₃ and TcN₄ exhibit remarkable bulk properties and can be potential ultrastiff and hard materials.Нітриди технеція з різною ідеальної стехіометрією досліджені із застосуванням методу перших принципів при тисках від 0 до 60 ГПа. Встановлено, що може бути багато стабільних нітридів технеція, включаючи Tc₃N, Tc₂N, ТКС, Tc₂N₃, TcN₂, TcN₃ і TcN₄, серед яких субнітриди Tc₃N і Tc₂N синтезуються при нульовому тиску і можуть бути використані для обробки ядерних відходів, таких як виділений при ядерному паливному циклі радіоактивний 99Tc. Більш того, TcN₃ і TcN₄, збагачені N, демонструють чудові об’ємні властивості і можуть бути потенційними ультражорсткими і твердими матеріалами.Нитриды технеция с различной идеальной стехиометрией исследованы с применением метода первых принципов при давлениях от 0 до 60 ГПа. Установлено, что может быть много стабильных нитридов технеция, включая Tc₃N, Tc₂N, ТКС, Tc₂N₃, TcN₂, TcN₃ и TcN₄, среди которых субнитриды Tc₃N и Tc₂N синтезируются при нулевом давлении и могут быть использованы для обработки ядерных отходов, таких как выделенный при ядерном топливном цикле радиоактивный 99Tc. Более того, TcN₃ и TcN₄, обогащенные N, демонстрируют замечательные объемные свойства и могут быть потенциальными ультражесткими и твердыми материалами
Influence of Carbon Concentration on the Superconductivity in MgCxNi3
The influence of carbon concentration on the superconductivity (SC) in
MgCNi has been investigated by measuring the low temperature specific
heat combined with first principles electronic structure calculation. It is
found that the specific heat coefficient of the
superconducting sample () in normal state is twice that of the
non-superconducting one (). The comparison of measured
and the calculated electronic density of states (DOS) shows that the
effective mass renormalization changes remarkably as the carbon concentration
changes. The large mass renormalization for the superconducting sample and the
low (7K) indicate that more than one kind of boson mediated
electron-electron interactions exist in MgCNi.Comment: 4 pages, 4 figure
Evaluation of the Dynamic Characteristics of AZ91D Crankcase Covers and Boxes
Dynamic tests are performed on similarly structured crankcase covers and boxes made of AZ91D magnesium and A380 aluminum alloys. The real vibration and noise control effect of an AZ91D magnesium alloy is evaluated, based on the behavior of the integral frequency response function, which is derived from the measured surface vibrations of the crankcase cover under operating conditions. The results indicate that crankcase covers and boxes made of AZ91D magnesium and A380 aluminum alloys with the same geometry possess similar normal characteristics. Both materials are interchangeable. However, the stiffness of AZ91D crankcase covers and boxes is poor. It is also difficult to obtain good engineering vibration and noise effects in the real structure due to an AZ91D high damping capacity. At the same excitation and frequency response at different structure characteristics, the measurement analysis of time-domain response indicates that methods to strengthen the crankcase box stiffness, such as embedding a main bearing steel sleeve, is favorable for improving the dynamic characteristics of an AZ91D crankcase box.Динамические испытания проводили на картерных крышках и поддонах аналогичной конструкции, изготовленных из магниевого AZ91D и алюминиевого А380 сплавов. Оценен эффект от применения магниевого сплава AZ91D для контроля реальной вибрации и шума на основании характера интегральной частотной функции отклика, полученной по результатам измерения поверхностной вибрации картерной крышки в рабочем режиме. Результаты показывают, что картерные крышки и поддоны, изготовленные из магниевого AZ91D и алюминиевого А380 сплавов, с одинаковыми геометрическими параметрами имеют аналогичные нормальные характеристики. Оба материала взаимозаменяемы. Однако картерная крышка и поддон из сплава AZ91D обладают низкой жесткостью. Достичь нормального технического уровня вибрации и шума в реальной конструкции также затруднительно, поскольку сплав AZ91D обладает высокой демпфирующей способностью. При одинаковом возбуждении и частотной характеристике конструкции с различными параметрами анализ измерения временной области показывает, что методы увеличения жесткости картерного поддона, например вмонтирование главного стального подшипника скольжения, способствуют улучшению динамических характеристик картерного поддона из сплава AZ91D
Dynamics of the self-interacting chameleon cosmology
In this article we study the properties of the flat FRW chameleon cosmology
in which the cosmic expansion of the Universe is affected by the chameleon
field and dark energy. In particular, we perform a detailed examination of the
model in the light of numerical analysis. The results illustrate that the
interacting chameleon filed plays an important role in late time universe
acceleration and phantom crossing.Comment: 13 pages, 8 figures, to appear in Astrophysics and Space Sc
Space Weather Application Using Projected Velocity Asymmetry of Halo CMEs
Halo coronal mass ejections (HCMEs) originating from regions close to the
center of the Sun are likely to be responsible for severe geomagnetic storms.
It is important to predict geo-effectiveness of HCMEs using observations when
they are still near the Sun. Unfortunately, coronagraphic observations do not
provide true speeds of CMEs due to the projection effects. In the present
paper, we present a new technique allowing estimate the space speed and
approximate source location using projected speeds measured at different
position angles for a given HCME (velocity asymmetry). We apply this technique
to HCMEs observed during 2001-2002 and find that the improved speeds are better
correlated with the travel times of HCMEs to Earth and with the magnitudes
ensuing geomagnetic storms.Comment: accepted for [publication in Solar Physic
Influence of the detector's temperature on the quantum Zeno effect
In this paper we study the quantum Zeno effect using the irreversible model
of the measurement. The detector is modeled as a harmonic oscillator
interacting with the environment. The oscillator is subjected to the force,
proportional to the energy of the measured system. We use the Lindblad-type
master equation to model the interaction with the environment. The influence of
the detector's temperature on the quantum Zeno effect is obtained. It is shown
that the quantum Zeno effect becomes stronger (the jump probability decreases)
when the detector's temperature increases
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