Topology of pocket formation in turbulent premixed flames

© 2018 The Combustion Institute. In turbulent premixed flame propagation, the formation of isolated pockets of reactants or products is associated with flame pinch-off events which cause rapid changes in the flame surface area. Previous topological analysis of these phenomena has been carried out based on Morse theory and Direct Numerical Simulation (DNS) in two spatial dimensions. The present work extends the topological analysis to three dimensions with emphasis on the formation and subsequent burnout of reactant pockets. Singular behaviour observed previously for terms of the Surface Density Function (SDF) transport equation in the two-dimensional case is shown to occur also in three dimensions. Further singular behaviour is observed in the displacement speed close to reactant pocket burnout. The theory is compared against DNS data from hydrogen-air flames and good agreement is obtained

Comparison of push-out bond strength of bioceramic sealer with bioceramic coated and non-bioceramic coated Guttapercha: an in vitro study

Background: The goal of the endodontic treatment is to achieve a fluid-tight impervious seal to prevent the ingress of bacteria and the occurrence of any pathology in future. The endodontic sealer plays a crucial role in obtaining the hermetic seal by filling all the spaces and by binding to the root dentin and to the core obturating material, which is usually gutta-percha. Aim: This study aimed to compare the push-out bond strength of Endosequence BC sealer with bioceramic coated gutta-percha and non-bioceramic coated gutta-percha. Materials and methods: A total of 36 extracted human maxillary central incisors were decoronated to standardize the root length of 15mm. Working length was determined and Biomechanical preparation for all the samples was done with a Mtwo (VDW Company) rotary file till 40/.06. Samples were randomly divided into three groups containing 12 teeth in each group based on the obturation procedure, namely Group 1: Endosequence BC sealer along with Endosequence bioceramic coated gutta-percha (n=12), Group 2: Endosequence BC sealer along with normal gutta-percha (n=12), Group 3: AH Plus sealer along with normal gutta-percha. All the samples were obturated using single cone technique. The specimens were sectioned orthogonally at middle third to obtain three sections of 1mm thick. All the samples were subjected to the push-out bond strength test with the universal testing machine. The data were subjected to one-way Analysis of Variance (ANOVA) followed by post hoc analysis. Results: Samples obturated with Endosequence BC sealer with Endosequence bioceramic coated gutta-percha showed the maximum push-out bond strength followed by Group 3 and Group 2.  One-way Anova showed significant differences (p=0.021) among the groups. In posthoc analysis, the specimens from group 1 exhibited significant differences (p=0.016) with the group 2 specimens. Conclusion: The push-out bond strength of Endosequence Bioceramic sealer with Endosequence Bioceramic coated gutta-percha was significantly higher than that of Endosequence Bioceramic sealer with normal gutta-percha and AH Plus sealer with normal gutta-percha

Attention deficit hyperactivity disorder symptoms, comorbidities, substance use, and social outcomes among men and women in a canadian sample

Background. Attention deficit hyperactivity disorder (ADHD) is a neurodevelopmental disorder that can persist in adolescence and adulthood. Aim. To examine prevalence of ADHD symptoms and correlates in a representative sample of adults 18 years and older living in Ontario, Canada. Method. We used the Centre for Addiction and Mental Health Monitor, an ongoing cross-sectional telephone survey, to examine the relationships between ADHD positive symptoms and comorbidities, substance use, medication use, social outcomes, and sociodemographics. Results. Of 4014 residents sampled in 2011-2012, 3.30% (2.75%-3.85%) screened positively for ADHD symptoms (women = 3.6%; men = 3.0%). For men, distress, antisocial symptoms, cocaine use, antianxiety medication use, antidepressant medication use, and criminal offence arrest were associated with positive ADHD screen. For women, distress, cocaine use, antianxiety medication use, antidepressant medication use, pain medication use, and motor vehicle collision in the past year were associated with positive ADHD screen. Conclusions. ADHD symptoms are associated with adverse medical and social outcomes that are in some cases gender specific

Dengue virus infection elicits highly polarized CX3CR1+ cytotoxic CD4+ T cells associated with protective immunity

Dengue virus (DENV) is a rapidly spreading pathogen with unusual pathogenesis, and correlates of protection from severe dengue disease and vaccine efficacy have not yet been established. Although DENV-specific CD8+ T-cell responses have been extensively studied, the breadth and specificity of CD4+ T-cell responses remains to be defined. Here we define HLA-restricted CD4+ T-cell epitopes resulting from natural infection with dengue virus in a hyperepidemic setting. Ex vivo flow-cytometric analysis of DENV-specific CD4+ T cells revealed that the virus-specific cells were highly polarized, with a strong bias toward a CX3CR1+ Eomesodermin+ perforin+ granzyme B+ CD45RA+ CD4 CTL phenotype. Importantly, these cells correlated with a protective HLA DR allele, and we demonstrate that these cells have direct ex vivo DENV-specific cytolytic activity. We speculate that cytotoxic dengue-specific CD4+ T cells may play a role in the control of dengue infection in vivo, and this immune correlate may be a key target for dengue virus vaccine development

Neodymium isotope constraints on provenance, dispersal, and climate-driven supply of Zambezi sediments along the Mozambique Margin during the past ∼45,000 years

Marine sediments deposited off the Zambezi River that drains a considerable part of the southeast African continent provide continuous records of the continental climatic and environmental conditions. Here we present time series of neodymium (Nd) isotope signatures of the detrital sediment fraction during the past ~45,000 years, to reconstruct climate-driven changes in the provenance of clays deposited along the Mozambique Margin. Coherent with the surface current regime, the Nd isotope distribution in surface sediments reveals mixing of the alongshore flowing Zambezi suspension load with sediments supplied by smaller rivers located further north. To reconstruct past changes in sediment provenances, Nd isotope signatures of clays that are not significantly fractionated during weathering processes have been obtained from core 64PE304-80, which was recovered just north of the Zambezi mouth at 1329 m water depth. Distinctly unradiogenic clay signatures (ENd values <214.2) are found during the Last Glacial Maximum, Heinrich Stadial 1, and Younger Dryas. In contrast, the Nd isotope record shows higher, more radiogenic isotope signatures during Marine Isotope Stage 3 and between ~15 and ~5 ka BP, the latter coinciding with the timing of the northern hemisphere African Humid Period. The clay-sized sediment fraction with the least radiogenic Nd isotope signatures was deposited during the Holocene, when the adjacent Mozambique Shelf became completely flooded. In general, the contribution of the distinctly unradiogenic Zambezi suspension load has followed the intensity of precession-forced monsoonal precipitation and enhanced during periods of increased southern hemisphere insolation and high-latitude northern hemispheric climate variability

Interferon-α resistance in renal carcinoma cells is associated with defective induction of signal transducer and activator of transcription 1 which can be restored by a supernatant of phorbol 12-myristate 13-acetate stimulated peripheral blood mononuclear cells

Therapy of selected human malignancies with interferon-α is widely accepted but often complicated by the emergence of interferon-α resistance. Interferon is a pleiotropic cytokine with antiproliferative, antitumour, antiviral and immunmodulatory effect; it signals through the Jak-STAT signal transduction pathway where signal transducer and activator of transcription 1 plays an important role. Here we report both, a lack of signal transducer and activator of transcription induction in interferon-α resistant renal cell carcinoma cells and signal transducer and activator of transcription 1 reinduction of phorbol 12-myristate 13-acetate-stimulated peripheral blood mononuclear cells supernatant. Preliminary experiments on the identification of the molecules that reinducing signal transducers and activators of transcription 1 indicate that interferon-γ may be the responsible candidate cytokine, but several others may be involved as well. This work provides the basis for therapeutic strategies directed at the molecular modulation of interferon-α resistance in human neoplasms