Diffusivities and kinetics of short-range and long-range orderings in Ni-Fe permalloys

The microscopic model of atomic diffusion is considered to describe the short-range order relaxation kinetics within the f.c.c.-Ni-Fe Permalloys. The model takes into account both the discrete and anisotropic characters of atomic jumps within the long-range field of concentration heterogeneities of the interacting atoms. The diffusion coefficients and activation energies for the disordered Ni-Fe permalloy are estimated with the evaluated probabilities of atomic jumps. As shown, the increasing of a temperature with a fixed composition influences on the 'potential' field of interatomic interaction ambiguously: the field 'potential' increases for defined coordination shells and decreases for some of other ones. Although the temperature increasing promotes the increasing of any atomic-probabilities jumps generally, but decreasing of the action of 'potential' field generated by the atoms of defined element and caused by its concentration heterogeneities onto the distant sites results in increasing of the atomic-jumps' probabilities of just this element, first of all, into the sites, which are more distant from the 'source' of heterogeneity. Within the framework of the static concentration waves' method along with the self-consistent field approximation, the Onsager-type kinetics equation is obtained to describe the long-range order relaxation by the L12-type superstructure. To calculate diffusivities for the ordered Ni3Fe permalloy, the independent, diffraction experimental data of the long-range order parameter relaxation are used. Theoretical curves of the long-range order time evolution for the non-stoichiometric f.c.c.-Ni-Fe permalloys are plotted. Decreasing of the concentration of alloying element results in decelerating of the long-range order parameter change and in increasing of its relaxation time

Superconducting joining of melt-textured Y-Ba-Cu-O bulk material

The Tm-Ba-Cu-O solder can be successfully used to produce a superconductive joint between MT-YBCO parts. The peculiarities of solidification, phase formation, structure transformations and electromagnetic properties of MT-YBCO soldered with TmBa2Cu3O7-d are discussed.Comment: PS of 6 pages text and 5 figures, presented at ICMC'2000, Brasi

АНАЛІЗ ПРОБЛЕМ ТА МОЖЛИВОСТЕЙ ВІДТВОРЕННЯ АРТИКУЛЯЦІНИХ РУХІВ ЩЕЛЕПИ У ЦИФРОВОМУ СЕРЕДОВИЩІ

Introduction. The use of virtual articulators, which are essentially software, greatly enhances the effectiveness of planning and implementing stages of complex dental rehabilitation with the ability to completely translate patient data (not only anatomical but also functional) into a digital format.The aim of study. Carry out an analysis of design and simulation systems for jaw kinematic parameters reproduction, basic principles of the architecture of existing software aimed at reproducing articulation components and constructing individualized occlusion patterns during patient-oriented prosthetic treatment.Materials and methods. The search for publications in electronic databases (PubMedCentral (PMC), BioMed Central, InTech, MEDLINE / PubMed, the Public Library of Science One (PloS)) was carried out in accordance with the Medical Subject Headings (MeSH) descriptors, which are peculiar headings categorized by the hierarchy system. Additionally, the analysis of references in already pre-made system reviews related to the objectives of this study and other review publications adjacent to them was provided.Results. The systematic review of the principles of digital modeling of articulation schemes with different initial conditions confirmed the possibility of their practical application during the manufacture of prosthetic elements with individualized occlusive surfaces, thus ensuring the achievement of the best results of dental rehabilitation.Conclusions. A systematic review of the main possibilities for reproduction jaw articulation movements in the digital environment is the primary stage in the development of an own model of a digital atticulator to address specific clinical problems associated with prosthetic retreatment of patients with present occlusive dysfunctions.Введение. Использование виртуальных артикуляторов, которые по сути представляют собой программное обеспечение, значительно повышает эффективность планирования и реализация этапов комплексной стоматологической реабилитации с возможностью полного перевода данных пациента (не только анатомических, но и функциональных) в цифровой формат.Цель исследования. Провести анализ систем дизайна и имитации кинематических параметров челюсти, основных принципов архитектуры имеющегося программного обеспечения направленного на воспроизводство артикуляционных составляющих и построение индивидуализированных окклюзионных схем в ходе пациент-ориентированного ортопедического лечения.Материалы и методы. Поиск публикаций в электронных базах данных (PubMedCentral (PMC), BioMed Central, InTech, MEDLINE / PubMed, Public Library of Science One (PloS)) осуществлялся согласно дескрипторов Medical Subject Headings (MeSH), представляющих собой своеобразные заголовки, категоризированных по системе иерархии. Дополнительно проводился анализ ссылок в уже предварительно проведенных системных обзорах, касающихся цели данного исследования, и других обзорных публикациях, смежных с ними.Результаты исследования. Проведенный системный обзор принципов цифрового моделирования артикуляционных схем с различными исходными условиями подтвердил возможность их практического применения при изготовлении протетических элементов с индивидуализированными окклюзионными поверхностями, обеспечивая таким образом достижение наиболее оптимальных результатов стоматологической реабилитации.Выводы. Системный обзор основных возможностей воспроизведения артикуляционных движений челюсти в цифровой среде является первичным этапом разработки собственной модели цифрового атикулятора для решения конкретных клинических проблем, связанных с повторным протезированием пациентов с имеющимися окклюзионными дисфункциями.Вступ. Використання віртуальних артикуляторів, що по суті представляють собою програмне забезпечення, значно підвищує ефективність планування та реалізація етапів комплексної стоматологічної реабілітації з можливістю повного переведення даних пацієнта (не тільки анатомічних, а й функціональних) у цифровий формат.Мета дослідження. Провести аналіз систем дизайну та імітації кінематичних параметрів щелепи, основних принципів архітектури наявного програмного забезпечення спрямованого на відтворення артикуляційних складових та побудову індивідуалізованих оклюзійних схем в ході пацієнт-орієнтованого ортопедичного лікування.Матеріали та методи. Пошук публікацій у електронних базах даних (PubMedCentral (PMC), BioMed Central, InTech, MEDLINE/ PubMed, Public Library of Science One (PloS)) здійснювався згідно дескрипторів Medical Subject Headings (MeSH), що становлять собою своєрідні заголовки, категоризовані за системою ієрархії. Додатково проводився аналіз посилань в уже попередньо проведених системних оглядах, що стосувалися мети даного дослідження, та інших оглядових публікаціях, суміжних із ними.Результати дослідження. Проведений системний огляд принципів цифрового моделювання артикуляційних схем з різними вихідними умовами підтвердив можливість їх практичного застосування під час виготовлення протетичних елементів з індивідуалізованими оклюзійними поверхнями, забезпечуючи таким чином досягнення найбільш оптимальних результатів стоматологічної реабілітації.Висновки. Системний огляд основних можливостей відтворення артикуляційних рухів щелепи в цифровому середовищі є первинним етапом розробки власної моделі цифрового атикулятора для вирішення конкретних клінічних проблем пов’язаних із повторним протезуванням пацієнтів із наявними оклюзійними дисфункціями

Sodium Phenylbutyrate Controls Neuroinflammatory and Antioxidant Activities and Protects Dopaminergic Neurons in Mouse Models of Parkinson’s Disease

Neuroinflammation and oxidative stress underlie the pathogenesis of various neurodegenerative disorders. Here we demonstrate that sodium phenylbutyrate (NaPB), an FDA-approved therapy for reducing plasma ammonia and glutamine in urea cycle disorders, can suppress both proinflammatory molecules and reactive oxygen species (ROS) in activated glial cells. Interestingly, NaPB also decreased the level of cholesterol but involved only intermediates, not the end product of cholesterol biosynthesis pathway for these functions. While inhibitors of both geranylgeranyl transferase (GGTI) and farnesyl transferase (FTI) inhibited the activation of NF-κB, inhibitor of GGTI, but not FTI, suppressed the production of ROS. Accordingly, a dominant-negative mutant of p21rac, but not p21ras, attenuated the production of ROS from activated microglia. Inhibition of both p21ras and p21rac activation by NaPB in microglial cells suggests that NaPB exerts anti-inflammatory and antioxidative effects via inhibition of these small G proteins. Consistently, we found activation of both p21ras and p21rac in vivo in the substantia nigra of acute 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) mouse model of Parkinson’s disease. Oral administration of NaPB reduced nigral activation of p21ras and p21rac, protected nigral reduced glutathione, attenuated nigral activation of NF-κB, inhibited nigral expression of proinflammatory molecules, and suppressed nigral activation of glial cells. These findings paralleled dopaminergic neuronal protection, normalized striatal neurotransmitters, and improved motor functions in MPTP-intoxicated mice. Consistently, FTI and GGTI also protected nigrostriata in MPTP-intoxicated mice. Furthermore, NaPB also halted the disease progression in a chronic MPTP mouse model. These results identify novel mode of action of NaPB and suggest that NaPB may be of therapeutic benefit for neurodegenerative disorders

Nck adapter proteins: functional versatility in T cells

Nck is a ubiquitously expressed adapter protein that is almost exclusively built of one SH2 domain and three SH3 domains. The two isoproteins of Nck are functionally redundant in many aspects and differ in only few amino acids that are mostly located in the linker regions between the interaction modules. Nck proteins connect receptor and non-receptor tyrosine kinases to the machinery of actin reorganisation. Thereby, Nck regulates activation-dependent processes during cell polarisation and migration and plays a crucial role in the signal transduction of a variety of receptors including for instance PDGF-, HGF-, VEGF- and Ephrin receptors. In most cases, the SH2 domain mediates binding to the phosphorylated receptor or associated phosphoproteins, while SH3 domain interactions lead to the formation of larger protein complexes. In T lymphocytes, Nck plays a pivotal role in the T cell receptor (TCR)-induced reorganisation of the actin cytoskeleton and the formation of the immunological synapse. However, in this context, two different mechanisms and adapter complexes are discussed. In the first scenario, dependent on an activation-induced conformational change in the CD3ε subunits, a direct binding of Nck to components of the TCR/CD3 complex was shown. In the second scenario, Nck is recruited to the TCR complex via phosphorylated Slp76, another central constituent of the membrane proximal activation complex. Over the past years, a large number of putative Nck interactors have been identified in different cellular systems that point to diverse additional functions of the adapter protein, e.g. in the control of gene expression and proliferation

Molecular Evolution of the Neuropeptide S Receptor

The neuropeptide S receptor (NPSR) is a recently deorphanized member of the G protein-coupled receptor (GPCR) superfamily and is activated by the neuropeptide S (NPS). NPSR and NPS are widely expressed in central nervous system and are known to have crucial roles in asthma pathogenesis, locomotor activity, wakefulness, anxiety and food intake. The NPS-NPSR system was previously thought to have first evolved in the tetrapods. Here we examine the origin and the molecular evolution of the NPSR using in-silico comparative analyses and document the molecular basis of divergence of the NPSR from its closest vertebrate paralogs. In this study, NPSR-like sequences have been identified in a hemichordate and a cephalochordate, suggesting an earlier emergence of a NPSR-like sequence in the metazoan lineage. Phylogenetic analyses revealed that the NPSR is most closely related to the invertebrate cardioacceleratory peptide receptor (CCAPR) and the group of vasopressin-like receptors. Gene structure features were congruent with the phylogenetic clustering and supported the orthology of NPSR to the invertebrate NPSR-like and CCAPR. A site-specific analysis between the vertebrate NPSR and the well studied paralogous vasopressin-like receptor subtypes revealed several putative amino acid sites that may account for the observed functional divergence between them. The data can facilitate experimental studies aiming at deciphering the common features as well as those related to ligand binding and signal transduction processes specific to the NPSR

Characterization of HIV seroconverters in a TDF/FTC PrEP study: HPTN 067/ADAPT

Background: HPTN 067/ADAPT evaluated tenofovir disoproxil fumarate/emtricitabine (TDF/FTC) pre-exposure prophylaxis (PrEP) in women (South Africa) and men who have sex with men (Thailand, US). Participants received once-weekly directly observed TDF/FTC (DOT), and were then randomized to daily, time-driven, or event-driven PrEP. This report describes characterization of 12 HIV seroconversion events in this trial. Methods: HIV rapid testing was performed at study sites. Retrospective testing included: 4th generation assays; HIV RNA testing; Western blot; an HIV-1/2 discriminatory assay; resistance testing; and antiretroviral (ARV) drug testing. Results: Six of the 12 seroconverters received TDF/FTC in the DOT phase, but were not randomized (3 were acutely infected at enrollment; 2 were infected during the DOT phase; one was not randomized due to pregnancy). One of the six randomized participants had acute infection at randomization but was not diagnosed for 3–4 months because HIV rapid tests were non-reactive; continued daily PrEP use was associated with false-negative antibody tests and low HIV RNA levels. The five participants infected after randomization included four with low adherence to the PrEP regimen, and one who reported a 7-day period without dosing prior to infection. Three participants had TDF/FTC resistance (M184I, K65R), including two who received only four once-weekly TDF/FTC doses; most TDF/FTC mutations were detected by next generation sequencing only. Conclusions: In HPTN 067/ADAPT, participants who acquired HIV infection had infrequent PrEP dosing or low/suboptimal adherence. Sensitive assays improved detection of HIV infection and drug resistance. Drug resistance was observed with limited PrEP exposure