Surface Properties of SiCp/Al Composite by Powder-Mixed EDM

AbstractThis paper uses a kind of moderate volume fraction (40%) of SiC particle reinforced Al matrix composites (SiCp/Al) to research how the surface properties are affected in conventional EDM (EDM) and powder-mixed EDM (PMEDM). By means of environment scanning electron microscope (ESEM) and HIT friction and wear tester, surface micro-topography, elements and wear resistance were analyzed. Experiments and researches indicate that compared with EDM, the surface properties machined by using PMEDM are improved greatly. The PMEDM surface roughness decreases about 31.5%; corrosion resistance is better too; and wear resistance is twice of EDM. Powder-mixed EDM has promising applications in metal matrix composites machining field

Inhibition of c-Jun NH2-terminal kinase stimulates mu opioid receptor expression via p38 MAPK-mediated nuclear NF-κB activation in neuronal and non-neuronal cells

AbstractDespite its potential side effects of addiction, tolerance and withdrawal symptoms, morphine is widely used for reducing moderate and severe pain. Previous studies have shown that the analgesic effect of morphine depends on mu opioid receptor (MOR) expression levels, but the regulatory mechanism of MOR is not yet fully understood. Several in vivo and in vitro studies have shown that the c-Jun NH2-terminal kinase (JNK) pathway is closely associated with neuropathic hyperalgesia, which closely resembles the neuroplastic changes observed with morphine antinociceptive tolerance. In this study, we show that inhibition of JNK by SP600125, its inhibitory peptide, or JNK-1 siRNA induced MOR at both mRNA and protein levels in neuronal cells. This increase in MOR expression was reversed by inhibition of the p38 mitogen-activated protein kinase (MAPK) pathway, but not by inhibition of the mitogen-activated protein/extracellular signal-regulated kinase (MEK) pathway. Further experiments using cell signaling inhibitors showed that MOR upregulation by JNK inhibition involved nuclear factor-kappa B (NF-κB). The p38 MAPK dependent phosphorylation of p65 NF-κB subunit in the nucleus was increased by SP600125 treatment. We also observed by chromatin immunoprecipitation (ChIP) analysis that JNK inhibition led to increased bindings of CBP and histone-3 dimethyl K4, and decreased bindings of HDAC-2, MeCP2, and histone-3 trimethyl K9 to the MOR promoter indicating a transcriptional regulation of MOR by JNK inhibition. All these results suggest a regulatory role of the p38 MAPK and NF-κB pathways in MOR gene expression and aid to our better understanding of the MOR gene regulation

Research on Rapidly Shaped Charge Cutting Technology of Aircraft Damaged Thin-Wall Structure

Shaped charge cutting technology has been introduced into the field of aircraft structure repair to rapidly reshape irregular holes in thin-walled structures. In the present research, numerical calculation of the dynamic cutting process by ANSYS and experiments of shaped charge cutting on a 2A12 aluminum alloy plate with 2 mm thickness have been carried out. It was found that fast kerf is smooth, producing a neat edge and good linearity. The incision fracture section is arranged in neat rows on a corrugated strip, and the lines are clear. Otherwise, the lower part is slightly messy without obvious distribution rules. The target plate separation method of cumulative cutting is a kind of “pre-penetration” and “late tear” method. The application of shaped charge cutting technology can aid in repair of aircrafts’ thin-walled structural damage

Efficacy and safety of ixekizumab through 52 weeks in two phase 3, randomised, controlled clinical trials in patients with active radiographic axial spondyloarthritis (COAST-V and COAST-W).

OBJECTIVES: To investigate the efficacy and safety of ixekizumab for up to 52 weeks in two phase 3 studies of patients with active radiographic axial spondyloarthritis (r-axSpA) who were biological disease-modifying antirheumatic drug (bDMARD)-naive (COAST-V) or tumour necrosis factor inhibitor (TNFi)-experienced (COAST-W). METHODS: Adults with active r-axSpA were randomised 1:1:1:1 (n=341) to 80 mg ixekizumab every 2 (IXE Q2W) or 4 weeks (IXE Q4W), placebo (PBO) or 40 mg adalimumab Q2W (ADA) in COAST-V and 1:1:1 (n=316) to IXE Q2W, IXE Q4W or PBO in COAST-W. At week 16, patients receiving ixekizumab continued their assigned treatment; patients receiving PBO or ADA were rerandomised 1:1 to IXE Q2W or IXE Q4W (PBO/IXE, ADA/IXE) through week 52. RESULTS: In COAST-V, Assessment of SpondyloArthritis international Society 40 (ASAS40) responses rates (intent-to-treat population, non-responder imputation) at weeks 16 and 52 were 48% and 53% (IXE Q4W); 52% and 51% (IXE Q2W); 36% and 51% (ADA/IXE); 19% and 47% (PBO/IXE). Corresponding ASAS40 response rates in COAST-W were 25% and 34% (IXE Q4W); 31% and 31% (IXE Q2W); 14% and 39% (PBO/IXE). Both ixekizumab regimens sustained improvements in disease activity, physical function, objective markers of inflammation, QoL, health status and overall function up to 52 weeks. Safety through 52 weeks of ixekizumab was consistent with safety through 16 weeks. CONCLUSION: The significant efficacy demonstrated with ixekizumab at week 16 was sustained for up to 52 weeks in bDMARD-naive and TNFi-experienced patients. bDMARD-naive patients initially treated with ADA demonstrated further numerical improvements after switching to ixekizumab. Safety findings were consistent with the known safety profile of ixekizumab. TRIAL REGISTRATION NUMBER: NCT02696785/NCT02696798

Cosmic histories of star formation and reionization: An analysis with a power-law approximation

With a simple power-law approximation of high-redshift ($\gtrsim3.5$) star formation history, i.e., $\dot{\rho}_*(z)\propto [(1+z)/4.5]^{-\alpha}$, we investigate the reionization of intergalactic medium (IGM) and the consequent Thomson scattering optical depth for cosmic microwave background (CMB) photons. A constraint on the evolution index $\alpha$ is derived from the CMB optical depth measured by the {\it Wilkinson Microwave Anisotropy Probe} (WMAP) experiment, which reads $\alpha\approx2.18\lg{\mathscr{N}_{\gamma}}-3.89$, where the free parameter $\mathscr{N}_\gamma$ is the number of the escaped ionizing ultraviolet photons per baryon. Moreover, the redshift for full reionization, $z_f$, can also be expressed as a function of $\alpha$ as well as $\mathscr{N}_{\gamma}$. By further taking into account the implication of the Gunn-Peterson trough observations to quasars for the full reionization redshift, i.e., $6\lesssim z_f \lesssim7$, we obtain $0.3\lesssim\alpha\lesssim1.3$ and $80\lesssim\mathscr{N}_{\gamma}\lesssim230$. For a typical number of $\sim4000$ of ionizing photons released per baryon of normal stars, the fraction of these photons escaping from the stars, $f_{\rm esc}$, can be constrained to within the range of $(2.0-5.8)$.Comment: 10 pages, 4 figures, accepted for publication in JCA

Geochronological and geochemical constraints on Late Cryogenian to Early Ediacaran magmatic rocks on the northern Tarim Craton:implications for tectonic setting and affinity with Gondwana

The Tarim Craton provides a geologic record of both the fragmentation of the Rodinian supercontinent and the subsequent assembly of Gondwana. However, the timing and interactions of these radically different tectonic processes remain contested. A critical part of this debate revolves around the Late Cryogenian-Ediacaran igneous rocks along the Craton’s northern margin, specifically, whether they record super-plume related Rodinian breakup or Gondwanan orogeny. To address this issue, we present zircon U-Pb-Hf isotopic data and whole rock geochemistry from Late Cryogenian to Early Ediacaran granitoids of the northern Tarim Craton. U-Pb zircon ages reveal three magmatic periods along the northern Tarim margin: ca. 660–640 Ma, 635–625 Ma and 620–600 Ma, associated with small scale felsic and mafic magmas. These granitoids have an A2-type affinity and are enriched in alkalines, but are depleted in Nb, Ta, Sr, P and Ti. Elemental data and generally negative εHf(t) values (−13.96 to 1.65) suggest that they were mainly derived from partial melting of enriched, subduction-modified lithospheric mantle triggered by upwelling of the asthenospheric mantle along the active continental margin of northern Tarim. We suggest that the Tarim Craton travelled as an isolated plate for much of the Late Neoproterozoic, near the outer part of Rodinia and subsequently Gondwana. During this time it was affected by localized and periodic subduction-related intrusion and eruption. However, within the samples of this study, there is no U-Pb-Hf isotopic and whole-rock geochemical evidence to support either super-plume-related rifting (i.e. Rodinian breakup) or Pan-African orogeny (i.e. Gondwanan assembly).</p

Observational constraint on generalized Chaplygin gas model

We investigate observational constraints on the generalized Chaplygin gas (GCG) model as the unification of dark matter and dark energy from the latest observational data: the Union SNe Ia data, the observational Hubble data, the SDSS baryon acoustic peak and the five-year WMAP shift parameter. It is obtained that the best fit values of the GCG model parameters with their confidence level are $A_{s}=0.73^{+0.06}_{-0.06}$ ($1\sigma$) $^{+0.09}_{-0.09}$ $(2\sigma)$, $\alpha=-0.09^{+0.15}_{-0.12}$ ($1\sigma$) $^{+0.26}_{-0.19}$ $(2\sigma)$. Furthermore in this model, we can see that the evolution of equation of state (EOS) for dark energy is similar to quiessence, and its current best-fit value is $w_{0de}=-0.96$ with the $1\sigma$ confidence level $-0.91\geq w_{0de}\geq-1.00$.Comment: 9 pages, 5 figure

The 2006 NESCent Phyloinformatics Hackathon: A Field Report

In December, 2006, a group of 26 software developers from some of the most widely used life science programming toolkits and phylogenetic software projects converged on Durham, North Carolina, for a Phyloinformatics Hackathon, an intense five-day collaborative software coding event sponsored by the National Evolutionary Synthesis Center (NESCent). The goal was to help researchers to integrate multiple phylogenetic software tools into automated workflows. Participants addressed deficiencies in interoperability between programs by implementing “glue code” and improving support for phylogenetic data exchange standards (particularly NEXUS) across the toolkits. The work was guided by use-cases compiled in advance by both developers and users, and the code was documented as it was developed. The resulting software is freely available for both users and developers through incorporation into the distributions of several widely-used open-source toolkits. We explain the motivation for the hackathon, how it was organized, and discuss some of the outcomes and lessons learned. We conclude that hackathons are an effective mode of solving problems in software interoperability and usability, and are underutilized in scientific software development

Reconstructing the Cosmic Expansion History up to Redshift z=6.29 with the Calibrated Gamma-Ray Bursts

Recently, Gamma-Ray Bursts (GRBs) were proposed to be a complementary cosmological probe to type Ia supernovae (SNIa). GRBs have been advocated to be standard candles since several empirical GRB luminosity relations were proposed as distance indicators. However, there is a so-called circularity problem in the direct use of GRBs. Recently, a new idea to calibrate GRBs in a completely cosmology independent manner has been proposed, and the circularity problem can be solved. In the present work, following the method proposed by Liang {\it et al.}, we calibrate 70 GRBs with the Amati relation using 307 SNIa. Then, following the method proposed by Shafieloo {\it et al.}, we smoothly reconstruct the cosmic expansion history up to redshift $z=6.29$ with the calibrated GRBs. We find some new features in the reconstructed results.Comment: 12 pages, 4 figures, 1 table, revtex4; v2: title changed, accepted by Eur. Phys. J. C; v3: published versio

Efficacy and safety of ixekizumab through 52 weeks in two phase 3, randomised, controlled clinical trials in patients with active radiographic axial spondyloarthritis (COAST-V and COAST-W)

Objectives To investigate the efficacy and safety of ixekizumab for up to 52 weeks in two phase 3 studies of patients with active radiographic axial spondyloarthritis (r-axSpA) who were biological disease-modifying antirheumatic drug (bDMARD)-naive (COAST-V) or tumour necrosis factor inhibitor (TNFi)-experienced (COAST-W).Methods Adults with active r-axSpA were randomised 1:1:1:1 (n=341) to 80 mg ixekizumab every 2 (IXE Q2W) or 4 weeks (IXE Q4W), placebo (PBO) or 40 mg adalimumab Q2W (ADA) in COAST-V and 1:1:1 (n=316) to IXE Q2W, IXE Q4W or PBO in COAST-W. At week 16, patients receiving ixekizumab continued their assigned treatment; patients receiving PBO or ADA were rerandomised 1:1 to IXE Q2W or IXE Q4W (PBO/IXE, ADA/IXE) through week 52.Results In COAST-V, Assessment of SpondyloArthritis international Society 40 (ASAS40) responses rates (intent-to-treat population, non-responder imputation) at weeks 16 and 52 were 48% and 53% (IXE Q4W); 52% and 51% (IXE Q2W); 36% and 51% (ADA/IXE); 19% and 47% (PBO/IXE). Corresponding ASAS40 response rates in COAST-W were 25% and 34% (IXE Q4W); 31% and 31% (IXE Q2W); 14% and 39% (PBO/IXE). Both ixekizumab regimens sustained improvements in disease activity, physical function, objective markers of inflammation, QoL, health status and overall function up to 52 weeks. Safety through 52 weeks of ixekizumab was consistent with safety through 16 weeks.Conclusion The significant efficacy demonstrated with ixekizumab at week 16 was sustained for up to 52 weeks in bDMARD-naive and TNFi-experienced patients. bDMARD-naive patients initially treated with ADA demonstrated further numerical improvements after switching to ixekizumab. Safety findings were consistent with the known safety profile of ixekizumab.Pathophysiology and treatment of rheumatic disease