94 research outputs found

    Enhanced mechanical, thermal and flame retardant properties by combining graphene nanosheets and metal hydroxide nanorods for Acrylonitrile–Butadiene–Styrene copolymer composite

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    Three metal hydroxide nanorods (MHR) with uniform diameters were synthesized, and then combined with graphene nanosheets (GNS) to prepare acrylonitrile–butadiene–styrene (ABS) copolymer composites. An excellent dispersion of exfoliated two-dimensional (2-D) GNS and 1-D MHR in the ABS matrix was achieved. The effects of combined GNS and MHR on the mechanical, thermal and flame retardant properties of the ABS composites were investigated. With the addition of 2 wt% GNS and 4 wt% Co(OH)2, the tensile strength, bending strength and storage modulus of the ABS composites were increased by 45.1%, 40.5% and 42.3% respectively. The ABS/GNS/Co(OH)2 ternary composite shows the lowest maximum weight loss rate and highest residue yield. Noticeable reduction in the flammability was achieved with the addition of GNS and Co(OH)2, due to the formation of more continuous and compact charred layers that retarded the mass and heat transfer between the flame and the polymer matrix

    Ultrasound screening and follow-up study of congenital anom-alies of the kidney and urinary tract in neonates

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    Objective: To investigate the incidence of congenital anomalies of the kidney and urinary tract (CAKUT)in neonates, and to evaluate the value of urinary ultrasound screening in the early postnatal period. Methods: The neonates born or treated in Beijing Tsinghua Changgung Hospital affiliated to Tsinghua University between January 2016 and December 2018 accepted the urinary ultrasound screening, and the neonates with problem were followed up. In the meanwhile, the maternal pregnancy data were analyzed to screen out the risk factors associated with the onset of CAKUT. Results: (1)A total of 2655 neonates were screened by ultrasonography, of whom 82 neonates had been diagnosed with CAKUT (male: 60 cases, female: 22 cases), the positive rate was 3. 1% (82 /2655). There were 66 cases of hydronephrosis, 6 cases of duplicate kidney, 2 cases of multiple renal cysts, 2 cases of renal cystic dysplasia, 1 case of medullary sponge kidney, 3 cases of small kidney, 1 case of isolated kidney, and 1 case of horseshoe kidney. (2)Of the 66 children with hydronephrosis, 4 cases were lost to the follow-up; 8 cases were followed for less than six months with no significant changes found, and still in the follow-up observation; 54 cases were followed up for 1 year, among which 32 cases were returned to normal within 1 year, 3 cases were alleviated, 7 cases were aggravated, and 12 cases were unchanged. One case underwent surgery for repeated urinary tract infections and decreased renal function. (3)Abnormal fetal urinary ultrasound in the late pregnancy was found to be the most common in the high risk factors of CAKUT. There were 44 high-risk newborns with abnormal fetal urinary ultrasound, and 35 cases of CAKUT were diagnosed after birth. The incidence rate was 795% (35 /44). (4)Among the 2655 newborns screened, 2611 newborns had normal antenatal urinary ultrasonography. Among these neonates with normal urinary ultrasound during pregnancy, 47 cases of CAKUT were diagnosed after birth, with an incidence of 18% (47 /2611). Conclusion: The most common CAKUT in neonates is hydronephrosis and most cases with hydronephrosis had a good prognosis, but they should be followed up regularly. Urinary ultrasound screening for neonates, especially those high-risk neonates with abnormal fetal urinary ultrasound, has important clinical implications for the early detection of CAKUT

    Effect of Annealing Process on CH 3

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    The morphology of compact TiO2 film used as an electron-selective layer and perovskite film used as a light absorption layer in planar perovskite solar cells has a significant influence on the photovoltaic performance of the devices. In this paper, the spin coating speed of the compact TiO2 is investigated in order to get a high-quality film and the compact TiO2 film exhibits pinhole- and crack-free films treated by 2000 rpm for 60 s. Furthermore, the effect of annealing process, including annealing temperature and annealing program, on CH3NH3PbI3-XClX film morphology is studied. At the optimal annealing temperature of 100°C, the CH3NH3PbI3-XClX morphology fabricated by multistep slow annealing method has smaller grain boundaries and holes than that prepared by one-step direct annealing method, which results in the reduction of grain boundary recombination and the increase of Voc. With all optimal procedures, a planar fluorine-doped tin oxide (FTO) substrate/compact TiO2/CH3NH3PbI3-XClX/Spiro-MeOTAD/Au cell is prepared for an active area of 0.1 cm2. It has achieved a power conversion efficiency (PCE) of 14.64%, which is 80.3% higher than the reference cell (8.12% PCE) without optimal perovskite layer. We anticipate that the annealing process with optimal compact TiO2 layer would possibly become a promising method for future industrialization of planar perovskite solar cells

    Blood Flow Velocity Changes in the Middle Cerebral Artery Induced by Driving Fatigue

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    Abstract. The cerebral blood flow velocity (CBFV) of middle cerebral artery (MCA) was detected during the fatigue driving using Transcranial Doppler. The CBFV was also analyzed after the fatigue driving by different means of relaxation to alleviate brain fatigue. The results show that the CBFV in MCA is reduced by driving fatigue

    Effect of Functionalized Graphene Oxide with Hyper-Branched Flame Retardant on Flammability and Thermal Stability of Cross-Linked Polyethylene

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    In this work, GO was functionalized by a hyper-branched flame retardant, which was synthesized by the reaction of N-aminoethyl piperazine and di(acryloyloxyethyl)methylphosphonate. Subsequently, the resultant functionalized GO (FGO) was incorporated into the cross-linked polyethylene (XLPE) to enhance the flame retardancy of the matrix. Transmission electron spectroscopy images indicated that FGO exhibited uniform dispersion in XLPE matrix and strong adhesion with the matrix by cross-linking, which improved barrier effect due to reduced heat release and the free radical transfer between the matrix and graphene nanosheets. The incorporation of FGO into XLPE matrix endowed polymer composites with flame retardancy and thermal stability. In addition, the homogeneous dispersion of functionalized GO with a hyper-branched flame retardant in the polymer matrix improved the antioxidation and mechanical properties of XLPE-FGO nanocomposites compared to the XLPE-GO samples, as demonstrated through the oxidative induction temperature and time test, oven aging test and mechanical test. © 2014 American Chemical Society

    An (E,E)-α-farnesene synthase gene of soybean has a role in defence against nematodes and is involved in synthesizing insect-induced volatiles

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    Plant terpene synthase genes (TPSs) have roles in diverse biological processes. Here, we report the functional characterization of one member of the soybean TPS gene family, which was designated GmAFS. Recombinant GmAFS produced in Escherichia coli catalysed the formation of a sesquiterpene (E,E)-a-farnesene. GmAFS is closely related to (E,E)-a-farnesene synthase gene from apple, both phylogenetically and structurally. GmAFS was further investigated for its biological role in defence against nematodes and insects. Soybean cyst nematode (SCN) is the most important pathogen of soybean. The expression of GmAFS in a SCN-resistant soybean was significantly induced by SCN infection compared with the control, whereas its expression in a SCN-susceptible soybean was not changed by SCN infection. Transgenic hairy roots overexpressing GmAFS under the control of the CaMV 35S promoter were generated in an SCN-susceptible soybean line. The transgenic lines showed significantly higher resistance to SCN, which indicates that GmAFS contributes to the resistance of soybean to SCN. In soybean leaves, the expression of GmAFS was found to be induced by Tetranychus urticate (two-spotted spider mites). Exogenous application of methyl jasmonate to soybean plants also induced the expression of GmAFS in leaves. Using headspace collection combined with gas chromatography–mass spectrometry analysis, soybean plants that were infested with T. urticae were shown to emit a mixture of volatiles with (E,E)-a-farnesene as one of the most abundant constituents. In summary, this study showed that GmAFS has defence roles in both below-ground and above-ground organs of soybean against nematodes and insects, respectively

    MiR-378a-5p Regulates Proliferation and Migration in Vascular Smooth Muscle Cell by Targeting CDK1

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    Objective: Abnormal proliferation or migration of vascular smooth muscle cells (VSMCs) can lead to vessel lesions, resulting in atherosclerosis and in stent-restenosis (IRS). The purpose of our study was to establish the role of miR-378a-5p and its targets in regulating VSMCs function and IRS.Methods: EdU assays and Cell Counting Kit-8 (CCK-8) assays were applied to evaluate VSMCs proliferation, wound healing assays and transwell assays were applied to assess cells migration. Furthermore, quantitative reverse transcription–polymerase chain reaction (qRT-PCR) was performed to investigate the expression level of miR-378a-5p IRS patients and healthy individuals. Target genes were predicted using Target Scan and miRanda software, and biological functions of candidate genes were explored through bioinformatics analysis. Moreover, RNA-binding protein immunoprecipitation (RIP) was carried out to analyze the miRNAs interactions with proteins. We also used Immunofluorescence (IF) and fluorescence microscopy to determine the binding properties, localization and expression of miR-378a-5p with downstream target CDK1.Results: The expression of miR-378a-5p was increased in the group with stent restenosis compared with healthy people, as well as in the group which VSMCs stimulated by platelet-derived growth factor-BB (PDGF-BB) compared with NCs. MiR-378a-5p over-expression had significantly promoted proliferative and migratory effects, while miR-378a-5p inhibitor suppressed VSMC proliferation and migration. CDK1 was proved to be the functional target of miR-378a-5p in VSMCs. Encouragingly, the expression of miR-378a-5p was increased in patients with stent restenosis compared with healthy people, as well as in PDGF-BB-stimulated VSMCs compared with control cells. Furthermore, co-transfection experiments demonstrated that miR-378a-5p over-expression promoted proliferation and migration of VSMCs specifically by reducing CDK1 gene expression levels.Conclusion: In this investigatory, we concluded that miR-378a-5p is a critical mediator in regulating VSMC proliferation and migration by targeting CDK1/p21 signaling pathway. Thereby, interventions aimed at miR-378a-5p may be of therapeutic application in the prevention and treatment of stent restenosis

    Microbial and Transcriptomic Profiling Reveals Diet-Related Alterations of Metabolism in Metabolic Disordered Mice

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    Metabolic disorders are the prelude of metabolic diseases, which are mainly due to the high-energy intake and genetic contribution. High-fat diet (HFD) or high-sucrose diet is widely used for inducing metabolic disorders characterized by increased body weight, insulin resistance, hepatic steatosis, and alteration of gut microbiome. However, the triangle relationship among diets, gut microbiome, and host metabolism is poorly understood. In our study, we investigated the dynamic changes in gut microbiota, and host metabolism in mice that were fed with either chow diet, HFD, or chow diet with 30% sucrose in drinking water (HSD) for continued 12 weeks. The gut microbiota was analyzed with 16S rDNA sequencing on feces. Hepatic gene expression profile was tested with transcriptomics analysis on liver tissue. The host metabolism was evaluated by measuring body weight, insulin sensitivity, serum lipids, and expression of proteins involved in lipid metabolism of liver. The results showed that HFD feeding affected body weight, insulin resistance, and hepatic steatosis more significantly than HSD feeding. 16S rRNA gene sequencing showed that HFD rapidly and steadily suppressed species richness, altered microbiota structure and function, and increased the abundance of bacteria responsible for fatty acid metabolism and inflammatory signaling. In contrast, HSD had minor impact on the overall bacteria structure or function but activated microbial bile acid biosynthesis. Fecal microbiota transplantation suggested that some metabolic changes induced by HFD or HSD feeding were transferrable, especially in the weight of white adipose tissue and hepatic triglyceride level that were consistent with the phenotypes in donor mice. Moreover, transcriptomic results showed that HFD feeding significantly inhibited fatty acid degradation and increase inflammation, while HSD increased hepatic de novo lipogenesis and inhibited primary bile acid synthesis alternative pathway. In general, our study revealed the dynamic and diversified impacts of HFD and HSD on gut microbiota and host metabolism
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