626 research outputs found

    Application of ultrasonic inspection in monitoring dynamic healing of mandibular fracture in rabbit model

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    AbstractObjectiveTo investigate the feasibility of ultrasonic diagnosis for monitoring fracture healing.MethodsThirty rabbit models with fraction of mandible body were established by surgically removing partial lower jawbone. At the 1st, 2nd, 4th, 6th, 8th and 12th week after the operation, they were examined by X-ray and ultrasound, respectively. All detection results were scored according to a generally accepted standard. Spearman rank correlation analysis was conducted to explore the relationship between the results of the two inspection methods.ResultsIn each healing stage, the results of the ultrasonic inspection were basically consistent with those of the X-ray examination, as supported by a Spearman rank correlation coefficient of 0.892 (P<0.001).ConclusionsNon-invasive ultrasonic inspection can be used instead of X-ray examination to monitor and diagnose fracture healing

    Motion parameter optimization of reciprocating vibrating screen based on discrete element method

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    Objective: To determine the precise quantitative relationship between screening efficiency and motion parameters for reciprocating vibrating screen, and to obtain the movement parameters with the optimal screening efficiency. Methods: Rocky was adopted to accurately simulate the movement behavior for wheat grain and wheat stem in the screening process, many factors orthogonal simulation test was used to investigate the effect of vibration frequency, amplitude, vibrating direction angle and screen surface inclination angle on screening efficiency. Results: The movement behaviors of wheat in the screening process was consistent with the theory analysis, which verified the correctness and feasibility of numerical simulation using Rocky. The vibration frequency, amplitude, vibrating direction angle and screen surface inclination angle have significant influence on the screening efficiency, and there is significant interaction between these motion parameters. The optimal motion parameter combination was the vibration frequency of 10 Hz, the amplitude of 2 mm, the vibration direction angle of 45° and the screen surface inclination angle of 0°. Conclusion: A regression model reflecting the quantitative relationship between motion parameters of and screening efficiency for reciprocating vibrating screen was established, and the optimal motion parameter combination of reciprocating vibrating screen was obtained

    Long-Term Nucleos(t)ide Analogues Therapy for Adults With Chronic Hepatitis B reduces the Risk of Long-Term Complications: a meta-analysis

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    <p>Abstract</p> <p>Background</p> <p>The effect of antiviral therapy in chronic hepatitis B (CHB) on reducing the risk of long-term complications (LTCs) remains unclear so far. To study whether long-term nucleos(t)ide analogues therapy can reduce the risk of long-term complications.</p> <p>Methods</p> <p>We searched MEDLINE, EMBASE, OVID, the Cochrane Central Register of Controlled Trials. Relative risks (RRs) of long-term complications with or without treatment were studied. Also subgroup analyses including the status of drug-resistance, HBeAg and pre-existing compensated cirrhosis were done using relative risks of long-term complications either with or without treatment or among nucleos(t)ide analogues treatment groups.</p> <p>Results</p> <p>Six eligible studies (3644 patients in all) were included. Data showed the incidence of long-term complications in treatment groups was induced by 74%(RR:0.26, 95% CI: 0.15-0.47) compared with no treatment. Whether drug-resistant happened or not during the long-term therapy, the incidence of long-term complications was still significantly induced respectively by 45%(RR: 0.55,95%CI:0.40-0.76) and 78% (RR:0.22, 95%CI: 0.13-0.36). For both different status of HBeAg and pre-existing compensated cirrhosis, there was significant lower incidence of long-term complications in treatment groups compared with no treatment, too. Moreover, among the NA treatment groups, patients with drug-resistance had 2.64 times (RR:2.64, 95%CI: 1.58-4.41) higher chance of developing to long-term complications, and patients with pre-existing compensated cirrhosis also had 3.07 times (RR:3.07, 95%CI: 1.04-9.11) higher chance of developing to long-term complications.</p> <p>Conclusions</p> <p>Long-term nucleos(t)ide analogue therapy for adults with CHB prevents or delays the development of long-term complications including decompensated cirrhosis, CHB-related death or CHB-related HCC in patients with CHB. The patients who need take antiviral drugs should receive the antiviral therapy as soon as possible.</p

    A one-dimensional ladder-like coordination polymer: poly[[hexa­aqua­bis(μ-5-nitro­benzene-1,3-dicarboxyl­ato-κ3 O,O′,O′′)(μ-oxalato-κ4 O,O′:O′′,O′′′)diyttrium(III)] trihydrate]

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    In the crystal structure of the title one-dimensional coordination polymer, [Y2(C8H3NO6)2(C2O4)(H2O)6]·3H2O, each YIII ion is bridged to its neighbours by two 5-nitro­benzene-1,3-dicarboxyl­ate (nbdc) dianions and one oxalate dianion (located on an inversion centre) to form a ladder-like polymeric structure. The two carboxylate groups of nbdc assume different modes of coordination, one is chelating whereas the other is monodentate. Three water mol­ecules coordinate to the YIII ion to complete an eight-coordinate distorted dodecahedral geometry. The ladder-like polymers are assembled together by hydrogen bonding and π–π stacking [centrio–centriod distance = 3.819 (9) Å] in the crystal structure

    Molecular Cloning, Expression Profile and 5′ Regulatory Region Analysis of Two Chemosensory Protein Genes from the Diamondback Moth, Plutella xylostella

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    Chemosensory proteins play an important role in transporting chemical compounds to their receptors on dendrite membranes. In this study, two full-length cDNA codings for chemosensory proteins of Plutella xylostella (Lepidoptera: Plutellidae) were obtained by RACE-PCR. PxylCSP3 and Pxyl-CSP4, with GenBank accession numbers ABM92663 and ABM92664, respectively, were cloned and sequenced. The gene sequences both consisted of three exons and two introns. RT-PCR analysis showed that Pxyl-CSP3 and Pxyl-CSP4 had different expression patterns in the examined developmental stages, but were expressed in all larval stages. Phylogenetic analysis indicated that lepidopteran insects consist of three branches, and Pxyl-CSP3 and Pxyl-CSP4 belong to different branches. The 5′regulatory regions of Pxyl-CSP3 and Pxyl-CSP4 were isolated and analyzed, and the results consist of not only the core promoter sequences (TATA-box), but also several transcriptional elements (BR-C Z4, Hb, Dfd, CF2-II, etc.). This study provides clues to better understanding the various physiological functions of CSPs in P. xylostella and other insects

    Alignment of Carbon Nanotube Additives for Improved Performance of Magnesium Diboride Superconductors

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    The rapid progress on MgB2 superconductor since its discovery[1] has made this material a strong competitor to low and high temperature superconductors (HTS) for applications with a great potential to catch the niche market such as in magnetic resonant imaging (MRI). Thanks to the lack of weak links and the two-gap superconductivity of MgB2 [2,3] a number of additives have been successfully used to enhance the critical current density, Jc and the upper critical field, Hc2.[4-12] Carbon nanotubes (CNTs) have unusually electrical, mechanical and thermal properties[13-16] and hence is an ideal component to fabricate composites for improving their performance. To take advantages of the extraordinary properties of CNTs it is important to align CNTs in the composites. Here we report a method of alignment of CNTs in the CNT/MgB2 superconductor composite wires through a readily scalable drawing technique. The aligned CNT doped MgB2 wires show an enhancement in magnetic Jc(H) by more than an order of magnitude in high magnetic fields, compared to the undoped ones. The CNTs have also significantly enhanced the heat transfer and dissipation. CNTs have been used mainly in structural materials, but here the advantage of their use in functional composites is shown and this has wider ramifications for other functional materials.Comment: 11 pages, 3 figures. to be published in Advanced Material

    Fibrosis progression in interferon treatment-naive Chinese plasma donors with chronic hepatitis C for 20 years: a cohort study

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    SummaryObjectivesTo evaluate the progression of fibrosis and factors influencing this in interferon (IFN) treatment-naive Chinese plasma donors infected with hepatitis C virus (HCV) for approximately 20 years.MethodsFrom July 2010 to June 2011, we investigated 122 IFN treatment-naive chronic hepatitis C (CHC) patients infected by plasma donation in 1992–1995. Liver fibrosis stage and inflammation grade were evaluated by Metavir and Scheuer scoring systems, respectively.ResultsOne hundred and twenty patients underwent liver biopsy. Liver biopsy was not performed in one patient with cirrhosis due to ascites, and another patient was excluded because of an invalid biopsy specimen. Cirrhosis was observed in three patients (fibrosis stage F4 in two patients revealed by biopsy, and one patient with ascites confirmed by physical and Doppler ultrasound examination). Fibrosis stages F1 and F2 were present in 55 and 50 patients, respectively. The severity of liver inflammation was independently related to moderate to severe fibrosis (F ≥2). Older age and male sex showed an increasing tendency for more severe fibrosis (F3/F4) in the present cohort.ConclusionsBased on histopathology results, the progression of fibrosis in patients with CHC infected by repeated plasma donation is slow after HCV infection of approximately 20 years. Liver inflammation is closely related to the development of moderate to severe liver fibrosis

    A general model for collaboration networks

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    In this paper, we propose a general model for collaboration networks. Depending on a single free parameter "{\bf preferential exponent}", this model interpolates between networks with a scale-free and an exponential degree distribution. The degree distribution in the present networks can be roughly classified into four patterns, all of which are observed in empirical data. And this model exhibits small-world effect, which means the corresponding networks are of very short average distance and highly large clustering coefficient. More interesting, we find a peak distribution of act-size from empirical data which has not been emphasized before of some collaboration networks. Our model can produce the peak act-size distribution naturally that agrees with the empirical data well.Comment: 10 pages, 10 figure
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