10 research outputs found

    Premixed edge-flames under transverse enthalpy gradients

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    We describe flame propagation between two opposed reactive streams which may differ in their composition and temperature. A two-dimensional counterflow configuration and an irreversible Arrhenius reaction are adopted, along with the constant density approximation. Attention is focused on the influence of two nondimensional parameters. The first one, denoted by γ, represents the difference in the enthalpy of the feed streams. The second one, ε, quantifies the ratio between the characteristic chemical time and the strain time. After a general formulation of the problem, we begin by an analysis of the one-dimensional case consisting of two parallel planar flames of unequal strength. The flames behavior is described analytically and numerically. In particular, two extinction regimes are identified: for values of γ smaller than a critical value γ*, the flames extinguish by quenching against each other at the stagnation plane; for γ > γ* they extinguish while at a finite distance from each other which increases with γ. These behaviors are similar to those, known in the literature, associated with the influence of Lewis numbers on the extinction of twin-flames. We then describe the propagation of two-dimensional flame fronts along the stagnation line, in a direction perpendicular to the plane of strain. The flame front is thus curved under the combined effects of the flow field and the transverse enthalpy gradient in the frozen mixture ahead of it; far behind the state of the gas is that of the pair of flat flames introduced above. The problem is studied numerically and complemented by an analytical description of the fast-chemistry situations corresponding to small values of ε. In particular we describe, for different fixed values of γ, the evolution of ignition fronts, characterized by a positive propagation speed, to extinction fronts, characterized by negative speeds, as ε is increased. In addition to the marked change in the flame shape, the most noticeable effect of an increase in γ is the decrease in the propagation speed of the flame front. These effects are associated with the increased front curvature for higher values of γ, along with a shift of the front leading edge towards the stream with higher enthalpy

    Expression of Duodenal Iron Transporter Proteins in Diabetic Patients with and without Iron Deficiency Anemia

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    The role of iron transport proteins in the pathogenesis of anemia in patients with diabetes mellitus (T2DM) is still unclear. We investigated the expression of duodenal transporter proteins in diabetic patients with and without iron deficiency anemia (IDA). Methods. Overall, 39 patients were included: 16 with T2DM and IDA (group A), 11 with T2DM without IDA (group B), and 12 controls (group C). Duodenal mucosal expression of divalent metal transporter 1 (DMT1), ferroportin 1 (FPN), hephaestin (HEPH), and transferrin receptor 1 (TfR) was evaluated by Western blotting. Chronic disease activity markers were measured as well. Results. FPN expression was increased in group A compared to group B and controls: 1.17 (0.72–1.46), 0.76 (0.53–1.04), and 0.71 (0.64–0.86), respectively (p=0.011). TfR levels were over expressed in groups A and B compared to controls: 0.39 (0.26–0.61), 0.36 (0.24–0.43), and 0.18 (0.16–0.24), respectively, (p=0.004). The three groups did not differ significantly with regard to cellular HEPH and DMT1 expression. The normal CRP and serum ferritin levels, accompanied with normal FPN among diabetic patients without IDA, do not support the association of IDA with chronic inflammatory state. Conclusion. In patients with T2DM and IDA, duodenal iron transport protein expression might be dependent on body iron stores rather than by chronic inflammation or diabetes per se

    The Relationship between Gender, Severity of Disease, Treatment Type, and Employment Outcome in Patients with Inflammatory Bowel Disease in Israel

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    Introduction. Since individuals with IBD typically experience symptoms during their prime years of employment, it raises the question about IBD impact on employment status. Most studies concentrated on absenteeism from work with varying results in different populations. However, absenteeism reflects only one dimension of the ability to work and does not expose the problem of inability to hold a full-time job. Aims. To evaluate the influence of IBD on unemployment and working hours in Israel. Secondary aims were to investigate the correlation between working hours and the type of medical treatment and the impact of severity of disease. Patients and Methods. Demographic data, employment status, number of weekly working hours, and disease parameters. The data was compared to that of the general Israeli population extracted from the website of the Central Bureau of Statistics. Results. 242 IBD patients were interviewed. Patients median age was 37.04(IQR 30.23-44.68) years and 88 (36.4%) were men and 154 (63.6%) women. Diagnosis of CD was established in 167 (69%) patients and UC in 65 (26.9%). There was no significant reduction in employment rates or working hours among the IBD patients comparing to the general population. Immunosuppressive or biologic treatment did not influence employment status. The unemployed patients had higher disease severity (median 7.33, IQR 5-10.66) compared to employed patients (median 6, IQR 3.66-7.66; p=0.003). Conclusions. Although IBD patients in Israel do not have higher unemployment, those with severe disease have lower proportion of employment

    Histone deacetylase inhibitors for purging HIV-1 from the latent reservoir.

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    Contains fulltext : 96985.pdf (publisher's version ) (Open Access)A reservoir of latently infected memory CD4(+) T cells is believed to be the source of HIV-1 reemergence after discontinuation of antiretroviral therapy. HIV-1 eradication may depend on depletion of this reservoir. Integrated HIV-1 is inaccessible for expression, in part because of histone deacetylases (HDACs). One approach is to exploit the ability of HDAC inhibitors to induce HIV-1 expression from an integrated virus. With effective antiretroviral therapy, newly expressed HIV-1 is incapable of reinfecting naive cells. With HIV-1 expression, one assumes the infected cell dies and there is a progressive reduction in the size of the reservoir. The concept was tested using the HDAC inhibitor valproic acid. However, valproic acid is weak in inducing HIV-1 from latency in vitro. As such, clinical trials revealed a small or no effect on reducing the number of latently infected T cells in the peripheral blood. However, the new HDAC inhibitors vorinostat, belinostat and givinostat are more effective at targeting specific HDACs for HIV-1 expression than valproic acid. Here, we review studies on HDAC inhibitor-induced expression of latent HIV-1, with an emphasis on new and specific HDAC inhibitors. With increased potency for HIV-1 expression as well as safety and ease of oral administration, new HDAC inhibitors offer a unique opportunity to deplete the latent reservoir. An additional benefit is the antiinflammatory properties of HDAC inhibitors, including downregulation of HIV-1 coreceptor expression

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