140 research outputs found
Radio-frequency spectroscopy of a strongly interacting spin-orbit coupled Fermi gas
We investigate experimentally and theoretically radio-frequency spectroscopy
and pairing of a spin-orbit-coupled Fermi gas of K atoms near a Feshbach
resonance at G. Experimentally, the integrated spectroscopy is
measured, showing characteristic blue and red shifts in the atomic and
molecular responses, respectively, with increasing spin-orbit coupling.
Theoretically, a smooth transition from atomic to molecular responses in the
momentum-resolved spectroscopy is predicted, with a clear signature of
anisotropic pairing at and below resonance. Our many-body prediction agrees
qualitatively well with the observed spectroscopy near the Feshbach resonance.Comment: 7 pages, 4 figures. Supercedes 1302.055
Activated NK cells kill hepatic stellate cells via p38/PI3K signaling in a TRAIL-involved degranulation manner
NK cells are important in regulating hepatic fibrosis via their cytotoxic killing of hepatic stellate
cells (HSCs). NK cells are activated by both cytokines such as IL-12 and IL-18, and innate immune
stimuli such as ligation of TLRs. The secretion of IL-18 depends upon activation of the inflammasome,
whereas TLRs are stimulated by microbial products. In the case of NK cells, IL-18 acts synergistically
with stimulation of TLR3 to cause cell activation and cytotoxic function. In the present
study, we activated NK cells to kill HSCs via IL-18 and TLR3 ligand stimulation, and dissected the
signaling pathways or molecules critical for such activation or killing. We find that such activation
depends on signaling via the p38/PI3K/AKT pathway, and that the activatedNK cells mediate
HSC death in a TRAIL-involved mechanism. As liver fibrosis is a major global health problem with
no good solution, these results emphasize that the p38/PI3K/AKT pathway in NK cells may be a
novel drug target to promote fibrosis regression
Clusterin confers gmcitabine resistance in pancreatic cancer
<p>Abstract</p> <p>Objective</p> <p>To measure clusterin expression in pancreatic cancer tissues and cell lines and to evaluate whether clusterin confers resistance to gmcitabine in pancreatic cancer cells.</p> <p>Methods</p> <p>Immunohistochemistry for clusterin was performed on 50 primary pancreatic cancer tissues and 25 matched backgrounds, and clusterin expression in 5 pancreatic cancer cell lines was quantified by Western blot and PT-PCR. The correlation between clusterin expression level and gmcitabine IC50 in pancreatic cancer cell lines was evaluated. The effect of an antisense oligonucleotide (ASO) against clusterin(OGX-011) on gmcitabine resistance was evaluated by MTT assays. Xenograft model was used to demonstrate tumor growth.</p> <p>Results</p> <p>Pancreatic cancer tissues expressed significantly higher levels of clusterin than did normal pancreatic tissues (<it>P </it>< 0.01). Clusterin expression levels were correlated with gmcitabine resistance in pancreatic cancer cell lines, and OGX-011 significantly decreased BxPc-3 cells resistance to gmcitabine (<it>P </it>< 0.01). <it>In vivo </it>systemic administration of AS clusterin and gmcitabine significantly decreased the s.c. BxPC-3 tumor volume compared with mismatch control ODN plus gmcitabine.</p> <p>Conclusion</p> <p>Our finding that clusterin expression was significantly higher in pancreatic cancer than in normal pancreatic tissues suggests that clusterin may confer gmcitabine resistance in pancreatic cancer cells.</p
IonâConducting Ceramic Membrane Reactors for the Conversion of Chemicals
Ionâconducting ceramic membranes, such as mixed oxygen ionic and electronic conducting (MIEC) membranes and mixed protonâelectron conducting (MPEC) membranes, have the potential for absolute selectivity for specific gases at high temperatures. By utilizing these membranes in membrane reactors, it is possible to combine reaction and separation processes into one unit, leading to a reduction in byâproduct formation and enabling the use of thermal effects to achieve efficient and sustainable chemical production. As a result, membrane reactors show great promise in the production of various chemicals and fuels. This paper provides an overview of recent developments in dense ceramic catalytic membrane reactors and their potential for chemical production. This review covers different types of membrane reactors and their principles, advantages, disadvantages, and key issues. The paper also discusses the configuration and design of catalytic membrane reactors. Finally, the paper offers insights into the challenges of scaling up membrane reactors from experimental stages to practical applications
Highly efficient preparation of Ce0.8Sm0.2O2-δâSrCo0.9Nb0.1O3-δ dual-phase four-channel hollow fiber membrane via one-step thermal processing approach
Fabricating dual-phase hollow-fiber membranes via a one-step thermal processing (OSTP) approach is challenging, because of complex sintering kinetics and the subsequent impacts on membrane morphology, phase stability, and permeation properties. In this study, we have demonstrated that Ce0.8Sm0.2O2-δ-SrCo0.9Nb0.1O3-δ (SDC-SCN) four-channel hollow fiber membrane can be manufactured via a single high-temperature sintering process, by using metal oxides and carbonates directly as membrane materials (sources of metal ions). It has been found that use of a low ramping rate reduces grain sizes, increases grain and forming cobalt oxide nanoparticles, a key step to promoting surface exchange process followed by enhancing oxygen permeation. While the grain boundary interface region can be limited to approximately 20â30 nm. At 1173 K oxygen permeation of the SDC-SCN four-channel hollow fiber membrane was measured at approximately 1.2 mL cmâ2¡minâ1 using helium as the sweep gas. Meanwhile, the dual-phase membrane shows a good tolerance to carbon dioxide, with the oxygen permeation flux fully recovered after long-term exposure to carbon dioxide (more than 100 h). This will enable further application of the OSTP approach for preparing dual-phase multi-channel hollow fiber membranes for applications of oxyfuel combustion, catalytic membrane reactors and carbon dioxide capture
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