108 research outputs found
Electromigration-Induced Flow of Islands and Voids on the Cu(001) Surface
Electromigration-induced flow of islands and voids on the Cu(001) surface is
studied at the atomic scale. The basic drift mechanisms are identified using a
complete set of energy barriers for adatom hopping on the Cu(001) surface,
combined with kinetic Monte Carlo simulations. The energy barriers are
calculated by the embedded atom method, and parameterized using a simple model.
The dependence of the flow on the temperature, the size of the clusters, and
the strength of the applied field is obtained. For both islands and voids it is
found that edge diffusion is the dominant mass-transport mechanism. The rate
limiting steps are identified. For both islands and voids they involve
detachment of atoms from corners into the adjacent edge. The energy barriers
for these moves are found to be in good agreement with the activation energy
for island/void drift obtained from Arrhenius analysis of the simulation
results. The relevance of the results to other FCC(001) metal surfaces and
their experimental implications are discussed.Comment: 9 pages, 13 ps figure
Recombinant Analogs of Sea Anemone Kunitz-Type Peptides Influence P2X7 Receptor Activity in Neuro-2a Cells
Purinergic P2X7 receptors (P2X7) have now been proven to play an important role and represent an important therapeutic target in many pathological conditions including neurodegeneration. Here, we investigated the impact of peptides on purinergic signaling in Neuro-2a cells through the P2X7 subtype in in vitro models. We have found that a number of recombinant peptides, analogs of sea anemone Kunitz-type peptides, are able to influence the action of high concentrations of ATP and thereby reduce the toxic effects of ATP. The influx of calcium, as well as the fluorescent dye YO-PRO-1, was significantly suppressed by the studied peptides. Immunofluorescence experiments confirmed that the peptides reduce the P2X7 expression level in neuronal Neuro-2a cells. Two selected active peptides, HCRG1 and HCGS1.10, were found to specifically interact with the extracellular domain of P2X7 and formed stable complexes with the receptor in surface plasmon resonance experiments. The molecular docking approach allowed us to establish the putative binding sites of the most active HCRG1 peptide on the extracellular domain of the P2X7 homotrimer and propose a mechanism for regulating its function. Thus, our work demonstrates the ability of the Kunitz-type peptides to prevent neuronal death by affecting signaling through the P2X7 receptor.publishedVersio
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Complex Structure of Lasiopodomys mandarinus vinogradovi Sex Chromosomes, Sex Determination, and Intraspecific Autosomal Polymorphism.
The mandarin vole, Lasiopodomys mandarinus, is one of the most intriguing species among mammals with non-XX/XY sex chromosome system. It combines polymorphism in diploid chromosome numbers, variation in the morphology of autosomes, heteromorphism of X chromosomes, and several sex chromosome systems the origin of which remains unexplained. Here we elucidate the sex determination system in Lasiopodomys mandarinus vinogradovi using extensive karyotyping, crossbreeding experiments, molecular cytogenetic methods, and single chromosome DNA sequencing. Among 205 karyotyped voles, one male and three female combinations of sex chromosomes were revealed. The chromosome segregation pattern and karyomorph-related reproductive performances suggested an aberrant sex determination with almost half of the females carrying neo-X/neo-Y combination. The comparative chromosome painting strongly supported this proposition and revealed the mandarin vole sex chromosome systems originated due to at least two de novo autosomal translocations onto the ancestral X chromosome. The polymorphism in autosome 2 was not related to sex chromosome variability and was proved to result from pericentric inversions. Sequencing of microdissection derived of sex chromosomes allowed the determination of the coordinates for syntenic regions but did not reveal any Y-specific sequences. Several possible sex determination mechanisms as well as interpopulation karyological differences are discussed
A clinical case of genetically confirmed myotubular myopathy
The aim of the study - presentation of a clinical case of genetically confirmed myotubular myopathy.Цель исследования – представление клинического случая генетически подтвержденной миотубулярной миопатии
A Large Hadron Electron Collider at CERN
This document provides a brief overview of the recently published report on
the design of the Large Hadron Electron Collider (LHeC), which comprises its
physics programme, accelerator physics, technology and main detector concepts.
The LHeC exploits and develops challenging, though principally existing,
accelerator and detector technologies. This summary is complemented by brief
illustrations of some of the highlights of the physics programme, which relies
on a vastly extended kinematic range, luminosity and unprecedented precision in
deep inelastic scattering. Illustrations are provided regarding high precision
QCD, new physics (Higgs, SUSY) and electron-ion physics. The LHeC is designed
to run synchronously with the LHC in the twenties and to achieve an integrated
luminosity of O(100) fb. It will become the cleanest high resolution
microscope of mankind and will substantially extend as well as complement the
investigation of the physics of the TeV energy scale, which has been enabled by
the LHC
Роль радионуклидной диагностики в комплексном обследовании ВИЧ-инфицированных пациентов с ишемической болезнью сердца
Cardiovascular disease is one of the most frequent cause of death globally. The greatest part is occupied by ischemic heart disease. HIV patients are composed to a higher risk of coronary heart disease.The purpose of this work is to evaluate the possibility of using molecular imaging methods in a comprehensive examination of patients with HIV infection and ischemic heart disease.Materials and methods. The survey group includes 32 patients with HIV infection. The comparison group consists of 25 age-matched patients with coronary heart disease and without HIV Infection. All patients were underwent myocardial perfusion scintigraphy using single photon emission computed tomography. Positron emission tomography with FDG were performed if necessary to assess the viability of the myocardium. The patients of the main group undergo diagnostic coronary angiography and standard set of laboratory and institutional diagnostic methods.Results. The results of which confirm the high efficiency of radionuclide diagnostic methods for detecting perfusion disorders, contractility and myocardial viability in patients with HIV infection even at an early stage. They can be recommended for using in a comprehensive examination of patients with HIV infection.Наиболее частой причиной смертности во всем мире являются сердечно-сосудистые заболевания, среди которых ведущее место занимает ишемическая болезнь сердца (ИБС). В группу с наиболее высоким риском развития ИБС входят пациенты с ВИЧ-инфекцией.Цель исследования: оценка возможности применения методов молекулярной визуализации в комплексном обследовании пациентов с ВИЧ-инфекцией и ИБС.Материал и методы. В группу обследования включено 32 пациента с ВИЧ-инфекцией, группу сравнения составили 25 сопоставимых по возрасту пациентов без ВИЧ-инфекции с ИБС. Всем пациентам проведена перфузионная сцинтиграфия миокарда (с помощью ОФЭКТ), ПЭТ/КТ сердца с ФДГ проводилась при необходимости оценки жизнеспособности миокарда в комплексе с диагностической коронароангиографией и стандартным набором лабораторно-инструментальных методов диагностики.Результаты. Полученные результаты подтверждают высокую эффективностью методов радионуклидной диагностики для выявления нарушений перфузии, сократимости и жизнеспособности миокарда у пациентов с ВИЧ-инфекцией даже на ранней стадии и могут быть рекомендованы к использованию в комплексном обследовании пациентов с ВИЧ-инфекцией
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