12,186 research outputs found
Enhanced treatment of coke plant wastewater using an anaerobic-anoxic-oxic membrane bioreactor system
No full textUse of submerged anaerobic-anoxic-oxic membrane bioreactor to treat highly toxic coke wastewater with complete sludge retention
No full textChalcopyrite Magnetic Semiconductors: An AB–Initio Study of Their Structural, Electronic and Magnetic Properties
No full textStimulated by recent experimental observations of room{temperature ferromagnetism of MnxCd1−xGeP2, we investigate the structural, electronic and magnetic properties of these systems as a function of Mn concentration by means of first–principles density-functional-theory-based codes. Moreover, we investigate the effect of the anion substitution (P vs As) in Mn-rich chalcopyirites. Our calculations indicate that the antiferromagnetic alignment is the most stable ordering for all the systems studied, at variance with that experimentally reported. Moreover, we find that there is a slight reduction of the total magnetic moment per Mn atom from ∼5 μB in all the Cd-rich P-based chalcopyrites to ∼4 μB in the Mn–rich MnGeP2 and MnGeAs2 systems
Solutal Convection of Liquid Al-3.5 wt%Li during Its Upward Solidification
No full textThe onset of solutal convection during the directional solidification of Bridgman type of liquid Al-3.5 wt%Li is studied. Based on the analysis of a liquid-inhomogeneous-porous-double-layer system, a bimodal feature of neutral stability curve is found. The pulling rate is ascertained as the governing parameter for the mode transition, i.e., it determines whether the microstructure in the mushy layer is related to convection after the system destabilizes
The protease complex consisting of dipeptidyl peptidase IV and seprase plays a role in the migration and invasion of human endothelial cells in collagenous matrices
No full textDipeptidyl peptidase IV (DPP4/CD26) and seprase / fibroblast activation protein alpha (FAP-α), are homologous type II transmembrane, homodimeric glycoproteins that exhibit unique prolyl peptidase activities. Human DPP4 is ubiquitously expressed in epithelial and endothelial cells and serves multiple functions in cleaving the penultimate positioned prolyl bonds at the N-terminus of a variety of physiologically important peptides in the circulation. Recent studies showed a linkage between DPP4 and down-regulation of certain chemokines and mitogenic growth factors, and degradation of denatured collagens (gelatin), suggesting a role of DPP4 in the cell invasive phenotype. Here, we found the existence of a novel protease complex consisting of DPP4 and seprase in human endothelial cells that were activated to migrate and invade in the ECM in vitro. DPP4 and seprase were co-expressed with the three major protease systems (MMP, PA and TTSP) at the cell surface and organize as a complex at invadopodia-like protrusions. Both proteases were co-localized at the endothelial cells of capillaries but not large blood vessels in invasive breast ductal carcinoma in vivo. Importantly, mAbs against the gelatin-binding domain of DPP4 blocked the local gelatin degradation by endothelial cells in the presence of the major metallo- and serine-protease systems that modified peri-cellular collagenous matrices, and subsequent cell migration and invasion. Thus, we have identified a novel mechanism involving the DPP4 gelatin-binding domain of the DPP4-seprase complex that facilitates the local degradation of the ECM and the invasion of the endothelial cells into collagenous matrices
Heterogeneous and tissue-specific regulation of effector T cell responses by IFN-gamma during Plasmodium berghei ANKA infection.
Full text linkIFN-γ and T cells are both required for the development of experimental cerebral malaria during Plasmodium berghei ANKA infection. Surprisingly, however, the role of IFN-γ in shaping the effector CD4(+) and CD8(+) T cell response during this infection has not been examined in detail. To address this, we have compared the effector T cell responses in wild-type and IFN-γ(-/-) mice during P. berghei ANKA infection. The expansion of splenic CD4(+) and CD8(+) T cells during P. berghei ANKA infection was unaffected by the absence of IFN-γ, but the contraction phase of the T cell response was significantly attenuated. Splenic T cell activation and effector function were essentially normal in IFN-γ(-/-) mice; however, the migration to, and accumulation of, effector CD4(+) and CD8(+) T cells in the lung, liver, and brain was altered in IFN-γ(-/-) mice. Interestingly, activation and accumulation of T cells in various nonlymphoid organs was differently affected by lack of IFN-γ, suggesting that IFN-γ influences T cell effector function to varying levels in different anatomical locations. Importantly, control of splenic T cell numbers during P. berghei ANKA infection depended on active IFN-γ-dependent environmental signals--leading to T cell apoptosis--rather than upon intrinsic alterations in T cell programming. To our knowledge, this is the first study to fully investigate the role of IFN-γ in modulating T cell function during P. berghei ANKA infection and reveals that IFN-γ is required for efficient contraction of the pool of activated T cells
Cfp1 is required for gene expression dependent H3K4me3 and H3K9 acetylation in embryonic stem cells
Full text linkBackgroundTrimethylation of histone H3 lysine 4 (H3K4me3) accumulates at promoters in a gene activity dependent manner. The Set1 complex is responsible for most H3K4me3 in somatic cells and contains the conserved subunit Cfp1, which is implicated in targeting the Set1 complex to CpG islands in mammals. In mouse embryonic stem cells, Cfp1 is necessary for H3K4me3 accumulation at constitutively active gene promoters, but is not required to maintain steady-state transcription of the associated gene.ResultsHere we show that Cfp1 is instrumental for targeting H3K4me3 to promoters upon rapid transcriptional induction in response to external stimuli. Surprisingly, H3K4me3 accumulation is not required to ensure appropriate transcriptional output but rather plays gene specific roles. We also show that Cfp1-dependent H3K4me3 deposition contributes to H3K9 acetylation genome wide, suggesting that Cfp1 dependent H3K4me3 regulates overall H3K9 acetylation dynamics and is necessary for histone acetyl transferase recruitment. Finally, we observe increased antisense transcription at the start and end of genes that require Cfp1 for accurate deposition of H3K4me3 and H3K9ac.ConclusionsOur results assign a key role for Cfp1 in establishing a complex active promoter chromatin state and shed light on how chromatin signaling pathways provide context-dependent transcriptional outcomes.</p
Comparative Study Of The Influence Of Natural Convection On Directional Solidification Of Al-3.5 Wt% Ni And Al-7 Wt% Si Alloys
Full text linkWe present numerical simulations of thermosolutal convection for directional solidification of Al-3.5 wt% Ni and Al-7 wt% Si. Numerical results predict that fragmentation of dendrite arms resulting from dissolution could be favored in Al-7 wt% Si, but not in Al-3.5 wt% Ni. Corresponding experiments are in qualitative agreement with the numerical predictions. Distinguishing the two fragmentation mechanisms, namely dissolution and remelting, is critical during experiments on earth, when fluid flow is dominant. (C) 2007 COSPAR. Published by Elsevier Ltd. All rights reserved
Hysteresis phenomenon and wetting characteristics of molten Sn-3.0 wt.%Ag-0.5 wt.%Cu on different tilting substrates
No full textThe hysteresis phenomenon and wetting characteristics of molten Sn-3.0 wt.%Ag-0.5 wt.%Cu on wetting and non-wetting tilting substrates at different temperatures were investigated. The viewpoint on negative interfacial tension was proposed in this paper to explain the spreading and wetting behaviors for sample on different tilted substrates. The critical sliding angle was defined as limited tilting angle of surface at which the molten drop slid down and the upper and lower contact angles of molten drop were measured as the advancing and receding contact angles, respectively. Wetting experiments were performed to determine how contact angle and contact hysteresis on alumina and oxygen-free copper tilting substrates changed with temperature. Static, limited tilting, advancing and receding contact angles on two kinds of substrates were measured at different temperatures. In general, both negative interfacial tension and hysteresis for sample on copper were much larger than that on alumina over the range of temperatures studied, indicating better wettability but worse motion characteristics for the former. It was due to the larger adhesion between solid and liquid than the cohesion of liquid, the negative interfacial tension and the acute contact angle. (C) 2009 Elsevier B.V. All rights reserved
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