1,536 research outputs found

    Utilizing swelling force to decrease the ice adhesion strength

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    The phase transformation that occurs during water freezing process is accompanied by volume expansion and the release of latent heat. The swelling force generated by this phase transformation can have a harmful impact on structural safety and integrity, as it can lead to bursting in roads, water pipes and reservoir dams. So, why not effectively adopt the swelling force as the active de-icing power to diminish the stability of the contact interface. This paper proposes a new method to remove this accumulated ice by using polymethyl methacrylate (pmma) and 6061 aluminum alloy with pits as substrate materials. Pits were filled with solutions of different freezing points; owing to the different freezing point between the pit solution and water, their phase transformations occurred at different time, where the solutions in the pit would freeze more slowly than the surface water. The generated phase swelling force directly acted on the contact interface and decreased the stability of the interface to decrease the ice adhesion strength. The experimental results showed that the ice adhesion strength was obviously affected and reduced by the swelling force in contrast to the ice adhesion strength on the smooth sample, and the reduction in ice adhesion strength changed depending on the filling solution. Compared to the ice adhesion strength of the specimen without pits, the frozen ice was completely separated from the ice-pmma interface owing to the water filling the pit. The ice adhesion strength on the surface of the aluminum alloy sample filled with 10% ethanol solution was reduced by 81.42%. Utilizing the phase swelling force to reduce the adhesion strength enhances the active de-icing ability of the material, providing a novel method for developing new anti-icing methods

    Gene Expression and Microarray Investigation of Dendrobium Mixture as Progressive Therapy for the Treatment of Type 2 Diabetes Mellitus

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    Purpose: To examine the gene expression profile, as well as blood sugar-lowering and lipid-lowering molecular mechanisms of Dendrobium mixtures in a diabetic rat model .Methods: Sprague Dawley (SD) rats were fed high-fat/high-glucose for 16 months. Those with random blood glucose > 16.7 mmol/L were used as the model group and treated with Dendrobium mixture (DEN, containing Dendrobium, Astragalus, Schisandra, etc) in clinically equivalent dose (12 g/kg). The liver RNA of the rats in all three groups (control, model and DEN) was used for Agilent genome expression microarray testing and subsequent data analysis.Result: Between the diabetic rat group and the wild-type group, 1339 functional genes showed differences in expression levels (p < 0.05). After Dendrobium treatment, only 380 genes showed differences in expression (p < 0.05). The expression level of nearly 1000 genes returned to normal after drug treatment (compared with the wild-type group, p > 0.05). Genes whose expression normalized were mainly those affected by the disease state and associated with glucose and lipid metabolism, cell growth, apoptosis, biosynthesis, olfactory receptors, or cytoskeletal proteins.Conclusion: Progressive therapy with Dendrobium mixture, which has glucose- and lipid-lowering effects, is associated with multi-gene  expression pathways. By treating diabetic r and wild-type rats withthe mixture, the disorder is further understood at the transcriptomic level.Keywords: Diabetes, Gene expression, Dendrobium mixture, Microarray testin

    Direct observation of the evolving metal–support interaction of individual cobalt nanoparticles at the titania and silica interface

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    Understanding the metal–support interaction (MSI) is crucial to comprehend how the catalyst support affects performance and whether this interaction can be exploited in order to design new catalysts with enhanced properties. Spatially resolved soft X-ray absorption spectroscopy (XAS) in combination with Atomic Force Microscopy (AFM) and Scanning Helium Ion-Milling Microscopy (SHIM) has been applied to visualise and characterise the behaviour of individual cobalt nanoparticles (CoNPs) supported on two-dimensional substrates (SiOxSi(100) (x < 2) and rutile TiO2(110)) after undergoing reduction–oxidation–reduction (ROR). The behaviour of the Co species is observed to be strongly dependent on the type of support. For SiOxSi a weaker MSI between Co and the support allows a complete reduction of CoNPs although they migrate and agglomerate. In contrast, a stronger MSI of CoNPs on TiO2 leads to only a partial reduction under H2 at 773 K (as observed from Co L3-edge XAS data) due to enhanced TiO2 binding of surface-exposed cobalt. SHIM data revealed that the interaction of the CoNPs is so strong on TiO2, that they are seen to spread at and below the surface and even to migrate up to ∼40 nm away. These results allow us to better understand deactivation phenomena and additionally demonstrate a new understanding concerning the nature of the MSI for Co/TiO2 and suggest that there is scope for careful control of the post-synthetic thermal treatment for the tuning of this interaction and ultimately the catalytic performance

    Experimental study on iron recovery by microwave carbon heat reduction-magnetic separation from red mud

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    To explore new ways to recycle red mud, this paper study on iron recovery by microwave carbon heat reductionmagnetic separation from red mud. Using orthogonal experimental method,study the effect of carbon to oxygen ratio, microwave power, heating time and slag former ratio on recovery of iron. The results show that microwave power is the main factor affecting iron recovery. After optimized by orthogonal experimental results, in the case when carbon to oxygen ratio is 1,5, microwave power is 3 000 W, heating time is 45 min, slag former ratio is 5 %, the grade and recovery of iron reach to 64,58 % and 90,64 % respectively. Analyzed comprehensivly by X-ray diffraction (XRD), Scanning Electron Microscope (SEM) and Energy Dispersive Spectrometer (EDS), Fe2O3 in red mud is reduced to Fe3O4 and Fe by microwave carbon heat reduction

    Multiscale petrographic heterogeneity and their implications for the nanoporous system of the Wufeng-Longmaxi shales in Jiaoshiba area, Southeast China: Response to depositional-diagenetic process

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    The organic matter-rich shales in Wufeng-Longmaxi Formation, Jiaoshiba area, Southeast China, are showing a notable petrographic heterogeneity characteristic within the isochronous stratigraphic framework, which lead to vast differences in the mineral composition and organic matter abundance in the adjacent sections of the shale reservoir. The studied shale has been divided into three systems tracts: a transgressive systems tract (TST), an early highstand systems tract (EHST), and a late highstand systems tract (LHST). Multiple-scale petrographic observation and detailed mineralogical and geochemical analyses were combined to investigate the manifestation, origin, and the ways by which the shale heterogeneity is affected. The results indicate that polytropic depositional environments lead to different components in sediment. Subsequently, these differences among shale sections become more apparent through different diagenetic pathways. During the deposition of the section TST, the Hirnantian glaciation and regional volcanism played a crucial role, contributing to the abundant accumulation of fine-grained intrabasinal silica and organic matter. In diagenesis stage, authigenic quartz aggregates derived from siliceous organisms are formed. They filled in primary interparticle pores, forming a rigid particle-bracing structure that provide effective resistivity against the compaction and spaces for organic matter migration and occlusion. Finally, the migrated organic matter left plenty of newly created pore spaces that constituted a great portion of the total porosity of shale reservoir. The depositional process of section EHST is strongly influenced by contour current, which brings about more extrabasinal influx and impoverishes organic matter. In diagenesis stage, the rigid particle-bracing structure could only be preserved in limited areas, since insufficient siliceous supply could not produce enough authigenic quartz. Primary interparticle pores are significantly reduced owing to compaction, leaving less space for later organic matter migration and occlusion. As a result, the total porosity of shale reservoir declines in this section. In a rapid tectonic-uplifting background, the deposition of section LHST is associated with a rapid increase in terrigenous clay minerals, which further dilutes organic matter. Ductile clay experienced strong compaction and then occupies most of the primary interparticle space. Rigid particles are wrapped by a large number of clays, which has destroyed the particle-bracing structure. As a result, the nanoporous system in the shale could not be well preserved

    Gluon fragmentation to ^3D_J quarkonia

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    We present a calculation of the leading order QCD fragmentation functions for gluons to split into spin-triplet D-wave quarkonia. We apply them to evaluate the gluon fragmentation contributions to inclusive ^3D_J quarkonium production at large transverse momentum processes like the Tevatron and find that the D-wave quarkonia, especially the charmonium 2^{--} state, could be observed through color-octet mechanism with present luminosity. Since there are distinctively large gaps between the contributions of two different (i.e, color-singlet and color-octet) quarkonium production mechanisms, our results may stand as a unique test to NRQCD color-octet quarkonium production mechanism.Comment: 15 pages in LaTex (2 figures in PS-file

    Seroepidemiology of Toxoplasma gondii infection in patients with liver disease in eastern China

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    The role of the protozoan parasite Toxoplasma gondii in the pathogenesis of liver disease has recently gained much interest. The aim of this study was to determine the prevalence and risk factors associated with T. gondii infection in patients with liver disease from three cities in Shandong and Henan provinces, China. A case–control study was conducted from December 2014 to November 2015 and included 1142 patients with liver disease and 1142 healthy controls. Serum samples were collected from all individuals and were examined with enzyme-linked immunosorbent assay for the presence of anti-T. gondii IgG and IgM antibodies. Information on the demographics, clinical, and lifestyle characteristics of the participants was collected from the medical records and by the use of a questionnaire. The prevalence of anti-T. gondii IgG was 19·7% in patients with liver disease compared with 12·17% in the controls. Only 13 patients had anti-T. gondii IgM antibodies compared with 12 control individuals (1·14% vs. 1·05%, respectively). The highest seroprevalence was detected in patients with liver cancer (22·13%), followed by hepatitis patients (20·86%), liver cirrhosis patients (20·42%), and steatosis patients (20%). Multivariate logistic regression analysis indicated that consumption of raw meat (odds ratio (OR) = 1·32; 95% confidence interval (CI) 1·01–1·71; P = 0·03) and source of drinking water from wells (OR = 1·56; 95% CI 1·08–2·27; P = 0·01) were independent risk factors for T. gondii infection in liver disease patients. These findings indicate that T. gondii infection is more likely to be present in patients with liver disease. Therefore, efforts should be directed toward health education of populations at high risk of T. gondii infection and measures should be taken to protect vulnerable patients with liver disease

    Selective Growth of Vertical-aligned ZnO Nanorod Arrays on Si Substrate by Catalyst-free Thermal Evaporation

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    By thermal evaporation of pure ZnO powders, high-density vertical-aligned ZnO nanorod arrays with diameter ranged in 80–250 nm were successfully synthesized on Si substrates covered with ZnO seed layers. It was revealed that the morphology, orientation, crystal, and optical quality of the ZnO nanorod arrays highly depend on the crystal quality of ZnO seed layers, which was confirmed by the characterizations of field-emission scanning electron microscopy, X-ray diffraction, transmission electron microscopy, and photoluminescence measurements. For ZnO seed layer with wurtzite structure, the ZnO nanorods grew exactly normal to the substrate with perfect wurtzite structure, strong near-band-edge emission, and neglectable deep-level emission. The nanorods synthesized on the polycrystalline ZnO seed layer presented random orientation, wide diameter, and weak deep-level emission. This article provides a C-free and Au-free method for large-scale synthesis of vertical-aligned ZnO nanorod arrays by controlling the crystal quality of the seed layer

    Acquisition of pneumococci specific effector and regulatory Cd4+ T cells localising within human upper respiratory-tract mucosal lymphoid tissue

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    The upper respiratory tract mucosa is the location for commensal Streptococcus (S.) pneumoniae colonization and therefore represents a major site of contact between host and bacteria. The CD4(+) T cell response to pneumococcus is increasingly recognised as an important mediator of immunity that protects against invasive disease, with data suggesting a critical role for Th17 cells in mucosal clearance. By assessing CD4 T cell proliferative responses we demonstrate age-related sequestration of Th1 and Th17 CD4(+) T cells reactive to pneumococcal protein antigens within mucosal lymphoid tissue. CD25(hi) T cell depletion and utilisation of pneumococcal specific MHCII tetramers revealed the presence of antigen specific Tregs that utilised CTLA-4 and PDL-1 surface molecules to suppress these responses. The balance between mucosal effector and regulatory CD4(+) T cell immunity is likely to be critical to pneumococcal commensalism and the prevention of unwanted pathology associated with carriage. However, if dysregulated, such responses may render the host more susceptible to invasive pneumococcal infection and adversely affect the successful implementation of both polysaccharide-conjugate and novel protein-based pneumococcal vaccines

    Rapid increase of scrub typhus incidence in Guangzhou, southern China, 2006-2014

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    Background: In the last decade, scrub typhus (ST) has been emerging or re-emerging in some areas of Asia, including Guangzhou, one of the most affected endemic areas of ST in China. Methods: Based on the data on all cases reported in Guangzhou from 2006 to 2014, we characterized the epidemiological features, and identified environmental determinants for the spatial distribution of ST using a panel negative binomial model. Results: A total of 4821 scrub typhus cases were reported in Guangzhou during 2006-2014. The annual incidence increased noticeably and the increase was relatively high and rapid in rural townships and among elderly females. The majority of cases (86.8%) occurred during May-October, and farmers constituted the majority of the cases, accounting for 33.9% in urban and 61.6% in rural areas. The number of housekeeper patients had a rapid increment in both rural and urban areas during the study period. Atmospheric pressure and relative humidity with lags of 1 or 2 months, distributions of broadleaved forest and rural township were identified as determinants for the spatiotemporal distribution of scrub typhus. Conclusion: Our results indicate that surveillance and public education need to be focused on the elderly farmers in rural areas covered with broadleaf forest in southern China
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