Неустойчивость двухслойных течений в проливах Черного моря

Рассмотрена плоская задача о прогрессивных гравитационных внутренних волнах в горизонтальном двухслойном течении Кельвина-Гельмгольца. Найдено аналитическое решение задачи и условия существования внутренних волн. Для течений с параметрами, типичными для пролива Босфор и Керченского пролива, рассчитаны характеристики бароклинных волн. В пространстве волновых чисел определены диапазоны устойчивости и неустойчивости двухслойных течений с характерными для этих проливов параметрами относительно малых возмущений в форме прогрессивных волн.Розглянуто плоску задачу про прогресивні гравітаційні внутрішні хвилі у горизонтальній двошаровій течії Кельвіна-Гельмгольца. Знайдено аналітичне рішення задачі та умови існування внутрішніх хвиль. Для течій з параметрами, типовими для протоки Босфор і Керченської протоки, розраховані характеристики бароклінних хвиль. У просторі хвильових чисел визначені діапазони стійкості і нестійкості двошарових течій з характерними для цих проток параметрами відносно малих збурень у формі прогресивних хвиль.The plane problem of the progressive internal gravity waves in a horizontal two-layer Kelvin-Helmholtz flow is considered. The analytical solution of the problem and the conditions of existence of internal waves are found. For the flows with the typical parameters for the Bosphorus Strait and the Strait of Kerch, characteristics of baroclinic waves are calculated. The stability and instability regimes of two-layer currents with characteristic parameters of these straits with respect to small wave disturbances are found in the space of wave numbers

Circulating gluten-specific FOXP3 + CD39 + regulatory T cells have impaired suppressive function in patients with celiac disease

Background Celiac disease is a chronic immune-mediated inflammatory disorder of the gut triggered by dietary gluten. Although the effector T-cell response in patients with celiac disease has been well characterized, the role of regulatory T (Treg) cells in the loss of tolerance to gluten remains poorly understood. Objective We sought to define whether patients with celiac disease have a dysfunction or lack of gluten-specific forkhead box protein 3 (FOXP3)+ Treg cells. Methods Treated patients with celiac disease underwent oral wheat challenge to stimulate recirculation of gluten-specific T cells. Peripheral blood was collected before and after challenge. To comprehensively measure the gluten-specific CD4+ T-cell response, we paired traditional IFN-γ ELISpot with an assay to detect antigen-specific CD4+ T cells that does not rely on tetramers, antigen-stimulated cytokine production, or proliferation but rather on antigen-induced coexpression of CD25 and OX40 (CD134). Results Numbers of circulating gluten-specific Treg cells and effector T cells both increased significantly after oral wheat challenge, peaking at day 6. Surprisingly, we found that approximately 80% of the ex vivo circulating gluten-specific CD4+ T cells were FOXP3+CD39+ Treg cells, which reside within the pool of memory CD4+CD25+CD127lowCD45RO+ Treg cells. Although we observed normal suppressive function in peripheral polyclonal Treg cells from patients with celiac disease, after a short in vitro expansion, the gluten-specific FOXP3+CD39+ Treg cells exhibited significantly reduced suppressive function compared with polyclonal Treg cells. Conclusion This study provides the first estimation of FOXP3+CD39+ Treg cell frequency within circulating gluten-specific CD4+ T cells after oral gluten challenge of patients with celiac disease. FOXP3+CD39+ Treg cells comprised a major proportion of all circulating gluten-specific CD4+ T cells but had impaired suppressive function, indicating that Treg cell dysfunction might be a key contributor to disease pathogenesis

Activator protein-1 (AP-1) signalling in human atherosclerosis: results of a systematic evaluation and intervention study

Animal studies implicate the AP-1 (activator protein-1) pro-inflammatory pathway as a promising target in the treatment of atherosclerotic disease. It is, however, unclear whether these observations apply to human atherosclerosis. Therefore we evaluated the profile of AP-1 activation through histological analysis and tested the potential benefit of AP-1 inhibition in a clinical trial. AP-1 activation was quantified by phospho-c-Jun nuclear translocation (immunohistochemistry) on a biobank of aortic wall samples from organ donors. The effect of AP-1 inhibition on vascular parameters was tested through a double blind placebo-controlled cross-over study of 28 days doxycycline or placebo in patients with symptomatic peripheral artery disease. Vascular function was assessed by brachial dilation as well as by plasma samples analysed for hs-CRP (high-sensitivity C-reactive protein), IL-6 (interleukin-6), IL-8, ICAM-1 (intercellular adhesion molecule-1), vWF (von Willebrand factor), MCP-1 (monocyte chemoattractant protein-1), PAI-1 (plasminogen activator inhibitor-1) and fibrinogen. Histological evaluation of human atherosclerosis showed minimal AP-1 activation in non-diseased arterial wall (i.e. vessel wall without any signs of atherosclerotic disease). A gradual increase of AP-1 activation was found in non-progressive and progressive phases of atherosclerosis respectively (P<0.044). No significant difference was found between progressive and vulnerable lesions. The expression of phospho-c-Jun diminished as the lesion stabilized (P<0.016) and does not significantly differ from the normal aortic wall (P<0.33). Evaluation of the doxycycline intervention only revealed a borderline-significant reduction of circulating hs-CRP levels (−0.51 μg/ml, P=0.05) and did not affect any of the other markers of systemic inflammation and vascular function. Our studies do not characterize AP-1 as a therapeutic target for progressive human atherosclerotic disease

The Clinical Variability of Maternally Inherited Diabetes and Deafness Is Associated with the Degree of Heteroplasmy in Blood Leukocytes

Context: Maternally inherited diabetes and deafness (MIDD) is a rare form of diabetes with a matrilineal transmission, sensorineural hearing loss, and macular pattern dystrophy due to an A to G transition at position 3243 of mitochondrial DNA (mtDNA) (m.3243A&gt;G). The phenotypic heterogeneity of MIDD may be the consequence of different levels of mutated mtDNA among mitochondria in a given tissue. Objective: The aim of the present study was thus to ascertain the correlation between the severity of the phenotype in patients with MIDD and the level of heteroplasmy in the blood leukocytes. Participants: The GEDIAM prospective multicenter register was initiated in 1995. Eighty-nine Europid patients from this register, with MIDD and the mtDNA 3243A&gt;G mutation, were included. Patients with MELAS (mitochondrial encephalomyopathy, lactic acidosis, and stroke-like episodes) or with mitochondrial diabetes related to other mutations or to deletions of mtDNA were excluded. Results: A significant negative correlation was found between levels of heteroplasmy and age of the patients at the time of sampling for molecular analysis, age at the diagnosis of diabetes, and body mass index. After adjustment for age at sampling for molecular study and gender, the correlation between heteroplasmy levels and age at the diagnosis of diabetes was no more significant. The two other correlations remained significant. A significant positive correlation between levels of heteroplasmy and HbA1c was also found and remained significant after adjustment for age at molecular sampling and gender. Conclusions: These results support the hypothesis that heteroplasmy levels are at least one of the determinants of the severity of the phenotype in MIDD. Heteroplasmy levels are at least one of the determinants of the severity of the phenotype of maternally inherited diabetes and deafness

Educação integral, institucionalização do tempo livre: outras lógicas educacionais no contexto Luso-Brasileiro

A finalidade principal do presente artigo é refletir sobre os debates que circundam a educação integral. Baseado em revisão bibliográfica de estudos específicos sobre essa temática, propõe um breve diálogo entre concepções de educação integral no Brasil e em Portugal, articulando-as com propostas no campo da educação não formal. São apresentadas observações sobre as peculiaridades da educação integral em ambos os países, atentos para outros jeitos de organizar o processo educacional, escapando de uma única lógica e do risco de institucionalização cada vez maior do tempo livre.The main purpose of the article is to reflect on the debates surrounding full-time education, and based on a bibliographical review of specific studies on the subject, to propose a brief dialogue between the conceptions of full-time education in Brazil and Portugal, articulating them with proposals in the field of non-formal education. Observations on the peculiarities of full-time education in both countries are presented here, attentive to other ways of organizing the educational process, escaping from a single logic and the risk of institutionalization of free time. Keywords: Full-time education; Non-formal and informal education; Community interventio

Déplacement par le xénon, du film d'hexafluorure de soufre préalablement adsorbé sur la face (0001) du graphite

Physisorption of xenon on the (0001) graphite previously covered with sulfur hexafluoride (SF6) has been studied between 80 and 112 K by a volumetric method. Xenon adsorption is strongly hindered by pre-adsorbed SF6 and becomes significant only under pressures definitively higher than on bare graphite. Xenon adsorption leads to the displacement on the preadsorbed SF6 film according to a first order phase transition process. The dependence of the transition pressure on temperature can probably be related to the different structures of the SF6 film on bare graphite.La physisorption de xénon sur la face (0001) du graphite recouverte d'hexafluorure de soufre (SF6) également physisorbé a été étudiée par volumétrie entre 80 et 112 K. La présence de SF6 contrarie fortement l'adsorption de xénon. Celui-ci ne s'adsorbe de façon importante qu'à des pressions nettement plus élevées que sur graphite nu en déplaçant le film de SF6 au cours d'une transition de phase du premier ordre. L'évolution de la pression de la transition de déplacement avec la température est vraisemblablement liée aux différentes structures que présente le film de SF6 sur graphite nu

Comparaison des propriétés thermodynamiques des films d'éthylène adsorbés sur nitrure de bore et graphite

The thermodynamic properties of ethylene film on boron nitride have been determined by volumetric method between 87 and 120 K. The results have been compared to those obtained previously with the same gas adsorbed on graphite. From the adsorption isotherms, the ethylene film has been shown to present a similar behaviour on the cleavage face of the two solids considered : 2D phase diagrams corresponding to the monolayer certainly of the same type ; first order « gas-liquid » transition in second, third, ... layers ; a finite number of layers below the saturation vapour pressure which increases with temperature.Les propriétés thermodynamiques du film d'éthylène sur nitrure de bore ont été déterminées par volumétrie entre 87 et 120 K. Elles sont comparées à celles du film du même gaz adsorbé sur graphite et étudiées précédemment Il ressort des isothermes d'adsorption que sur la face de clivage des deux solides considérés le film d'éthylène a un comportement analogue : diagrammes de phases 2D relatifs à la première couche certainement semblables ; transition du 1er ordre du type « gaz-liquide » en 2e, 3e,... couches dès la température où celles-ci se forment ; nombre croissant de couches lorsque l'on augmente la température

DE FISCALE WINSTBEPALING IN DE LID-STATEN VAN DE EUROMARKT (I)

DE FISCALE WINSTBEPALING IN DE LID-STATEN VAN DE EUROMARKT (I