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Now showing items 113 - 128 of 130

  • Occult hepatitis B virus infection among people with a family history of chronic hepatitis B virus infection.

    Zhang, Zhenhua   Zhang, Ling   Dai, Yu   Jin, Lei   Sun, Binghu   Su, Qian   Li, Xu  

    UNLABELLED: The prevalence of occult hepatitis B virus infection (OBI) among people with a family history of chronic hepatitis B virus (HBV) infection is unclear. Serum samples were collected from 747 hepatitis B surface antigen (HBsAg)-negative people with a family history of HBV infection and 579 HBsAg-negative volunteer blood donors. The presence of HBV DNA was evaluated using nested PCR with primers specific for the X, S, and C regions of HBV. The Pre-S1/Pre-S2/ S region PCR products for the OBI group and their family members with chronic HBV infection (control group) were sequenced and compared. The prevalence of OBI was 8.0% (60/747) among HBsAg-negative people with a family history of chronic HBV infection, compared to 2.6% (15/579) among the blood donors (P < 0.05). The prevalence of HBV genotype B infection was lower in the OBI group than in the control group (P =3D 0.031). The substitution rates in the major hydrophilic region and the "a" determinant seemed to be higher in the OBI group (0.893 vs. 0.507; 1.042 vs. 0.403, respectively), and stop codon mutations more frequent in the OBI sequences (OBI: 2/26, 7.7% vs.; CONTROL: 0/31, 0%). However, none of these differences was statistically significant (P =3D 0.237, 0.199, 0.201, respectively). In summary, the prevalence of OBI among HBsAg-negative people with a family history of chronic HBV infection was significantly higher than that in Chinese blood donors. However, S region mutations and the escape mechanism are not likely to be the major causes of increased prevalence of OBI. =C2=A9 2015 Wiley Periodicals, Inc.
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  • Well-defined triblock copolymers with a photolabile middle block of poly(phenyl vinyl ketone):facile synthesis,chain-scission mechanism and controllable photocleavability

    Guo, Ruiwei   Mei, Pengbo   Zhong, Qing   Yao, Yuan   Su, Qian   Zhang, Jianhua  

    The effective preparation of photoresponsive polymers with precisely controlled location and number of photolabile units in the main chain is essential for their applications. In this study, a series of photocleavable well-defined triblock copolymers with the photocleavable middle block of poly(phenyl vinyl ketone) (PPVK) were readily synthesized by RAFT polymerization. The chain structure and chemical composition of copolymers were characterized by (HNMR)-H-1, FTIR and GPC. The well-controlled molecular weights and low polydispersity (<1.30) demonstrated the excellent controllability and living characteristics of the RAFT process for the polymerization of PVK. Then the photocleavage mechanism and kinetics of PPVK-functionalized copolymers were systematically investigated by tracking, fractionating and quantifying the photolysis products using gradient polymer elution chromatography (GPEC). The results not only confirmed the rapid photocleavability of PPVK-based polymers, but also firstly provided direct evidence for the proposed Norrish type reaction mechanism of the chain scission of PPVK. Moreover, the investigation of the effect of the PPVK chain on the photolysis kinetics demonstrated that the photodegradation rate of PPVK-based polymers can be controlled by adjusting the PPVK chain length in block copolymers. As a preliminary application study, the self-assembled micelles of the obtained PPVK-based amphiphilic polymers under light irradiation were found to undergo photo-triggered rapid disassembly and exhibited photo-controllable emulsifiability. In sum, the incorporation of the highly photolabile PPVK into block copolymers by RAFT polymerization provides a promising strategy for the construction of complex polymeric architectures or nanostructures with controllable photocleavability.
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  • Experimental and numerical analyses of lightweight foamed concrete as filler for widening embankment

    Shi, Xiaona   Huang, Junjie   Su, Qian  

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  • Microchannel condensation: Correlations and theory

    Su, Qian   Yu, Guang Xu   Wang, Hua Sheng   Rose, John W.  

    Attention is drawn, to the fact that, while four different correlations for condensation in microchannels are in fair agreement for the case of R134a (on which the empirical constants in the correlations are predominately based) they differ markedly when applied to other fluids such as ammonia. A wholly theoretical model is compared with the correlations for both R134a and ammonia. (C) 2009 Elsevier Ltd and IIR. All rights reserved.
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  • A J-shaped association between soy food intake and depressive symptoms in Chinese adults

    Yu, Bin   Yu, Fei   Su, Qian   Zhang, Qing   Liu, Li   Meng, Ge   Wu, Hongmei   Xia, Yang   Bao, Xue   Shi, Hongbin   Gu, Yeqing   Fang, Liyun   Yang, Huijun   Sun, Shaomei   Wang, Xing   Zhou, Ming   Jia, Qiyu   Guo, Qi   Liu, Huijun   Song, Kun   Niu, Kaijun  

    Background & aims: Soy food has been proven to have multiple positive effects on human health, however, no study has yet investigated the association between habitual intake of soy food and depressive symptoms in general population. The objective of this study was to examine this association. Methods: In a cross-sectional analysis, we studied a sample of 13,760 adults (mean age 43.5 years) in Tianjin, China. The Self-Rating Depression Scale (SDS) was used to assess depressive symptoms, with four cut-off points (SDS >=3D 40, 45, 48 or 50) indicating increased level of depressive symptoms. Food Frequency Questionnaire (FFQ) was used to assess dietary intake. Results: In the total population, the prevalence of increased depressive symptoms was 7.2% (SDS >=3D 50). Comparing to the group with lowest intake frequency of soy food (=3D twice/day. Associations remained when other cut-off points (SDS >=3D 40, 45 or 48) were used as a definition of increased depressive symptoms. Conclusion: Findings from this study suggested a J-shaped association between intake frequency of soy food and incidence of depressive symptoms among adults. For the first time, the study provides evidence that light-to-moderate intake of soy food may reduce the incidence of depressive symptoms, while relatively high (>=3D twice/day) intake may generate the opposite effect. (C) 2017 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.
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  • Structures,formation mechanisms,and ion exchange properties of alpha-,beta-,and gamma-Na2TiO3

    Meng, Fancheng   Liu, Yahui   Xue, Tianyan   Su, Qian   Wang, Weijing   Qi, Tao  

    alpha-, beta-, and gamma-Na2TiO3 were prepared from rutile TiO2 and molten NaOH. Three models of beta-Na2TiO3 with space groups of R (3) over bar, P (1) over bar, and P (3) over bar were proposed, and the R (3) over bar model was refined from the experimental data by using the Rietveld method. The structure of beta-Na2TiO3 is a superstructure of alpha-Na2TiO3 and supposedly contains Ti6O19 clusters. The structures of Na2TiO3 were mainly determined by the particle sizes of rutile and the reaction temperatures. alpha-Na2TiO3 could be prepared from fine rutile particles (D(50) < 25.8 mu m) and molten NaOH at 500 degrees C or quenching the melt of Na2TiO3 at 1000 degrees C quickly. gamma- and beta-Na2TiO3 were the thermodynamically stable phases of Na2TiO3 at around 500 degrees C and above 800 degrees C, respectively. alpha-Na2TiO3 was formed far beyond the thermodynamically stable state. The Na+ in alpha-Na2TiO3 was easier to exchange with H+ in water than that in beta or gamma phases. They all converted to amorphous phases after the 2nd, 6th, and 4th water washings at 25 degrees C, respectively. beta-Na2TiO3 followed similar paths of ion exchange as alpha-Na2TiO3, which was different from that of gamma-Na2TiO3.
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  • Mechanism modeling for phase fraction measurement with ultrasound attenuation in oil-water two-phase flow

    Su, Qian   Tan, Chao   Dong, Feng  

    When measuring the phase fraction of oil-water two-phase flow with the ultrasound attenuation, the phase distribution and fraction have direct influence on the attenuation coefficient. Therefore, the ultrasound propagation at various phase fractions and distributions were investigated. Mechanism models describing phase fraction with the ultrasound attenuation coefficient were established by analyzing the interaction between ultrasound and two-phase flow by considering the scattering, absorption and diffusion effect. Experiments were performed to verify the theoretical analysis, and the test results gave good agreement with the theoretical analysis. When the dispersed phase fraction is low, the relationship between ultrasound attenuation coefficient and phase fraction is of monotonic linearity; at higher dispersed phase fraction, ultrasound attenuation coefficient presents an irregular response to the dispersed phase fraction. The presented mechanism models give reasonable explanations about the trend of ultrasound attenuation.
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  • Sustainable micro-manufacturing of superhydrophobic surface on ultrafine-grained pure aluminum substrate combining micro-embossing and surface modification

    Xu, Jie   Su, Qian   Shan, Debin   Guo, Bin  

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  • Monitoring and early warning method for a rockfall along railways based on vibration signal characteristics

    Yan, Yan   Li, Ting   Liu, Jie   Wang, Wubin   Su, Qian  

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  • Oncogenic functions of protein kinase D2 and D3 in regulating multiple cancer-related pathways in breast cancer

    Liu, Yan   Li, Jian   Ma, Zhifang   Zhang, Jun   Wang, Yuzhi   Yu, Zhenghong   Lin, Xue   Xu, Zhi   Su, Qian   An, Li   Zhou, Yehui   Ma, Xinxing   Yang, Yiwen   Wang, Feifei   Chen, Qingfei   Zhang, Yunchao   Wang, Jilinlin   Zheng, Huilin   Shi, Aihua   Yu, Shuang   Zhang, Jingzhong   Zhao, Weiyong   Chen, Liming  

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  • The Relationship Between Thyroid Function and the Prevalence of Type 2 Diabetes Mellitus in Euthyroid Subjects

    Gu, Yeqing   Li, Huihui   Bao, Xue   Zhang, Qing   Liu, Li   Meng, Ge   Wu, Hongmei   Du, Huanmin   Shi, Hongbin   Xia, Yang   Su, Qian   Fang, Liyun   Yu, Fei   Yang, Huijun   Yu, Bin   Sun, Shaomei   Wang, Xing   Zhou, Ming   Jia, Qiyu   Guo, Qi   Chang, Hong   Wang, Guolin   Huang, Guowei   Song, Kun   Niu, Kaijun  

    Purpose: Thyroid hormones (THs) are primarily responsible for the regulation of energy balance and metabolism, suggesting that TH levels may contribute to the development of type 2 diabetes mellitus (T2DM). However, few studies have investigated the relationship between TH and T2DM in a general population. The aim of this study was to evaluate whether serum TH levels within the reference range are related to T2DM. Methods: A cross-sectional study (n =3D 15,296) was performed in Tianjin, China. Serum free triiodothyronine (FT3), free thyroxine (FT4), and thyroid-stimulating hormone (TSH) levels were measured by chemiluminescence immunoassay, and T2DM was defined according to the American Diabetes Association criteria. Multiple logistic regression models were used to assess the sexspecific relationships between FT3, FT4, FT3/FT4 ratios, and TSH quintiles and T2DM. Results: The prevalence of T2DM was 16.2% in males and 7.7% in females. In males, the multivariable-adjusted odds ratios (95% confidence interval) of T2DM for increasing quintiles of FT3, FT4, and FT3/FT4 ratios were 1.00, 0.75(0.63 to 0.89), 0.70(0.58 to 0.84), 0.63(0.52 to 0.76), 0.56 (0.46 to 0.68; P for trend, 0.0001); 1.00, 1.05(0.87 to 1.27), 1.16(0.96 to 1.40), 1.09(0.90 to 1.31), 1.29 (1.07 to 1.56; P for trend =3D 0.01); and 1.00, 0.69(0.58 to 0.83), 0.72(0.60 to 0.86), 0.59(0.48 to 0.71), and 0.55(0.46 to 0.66; P for trend, 0.0001), respectively. Similar results also were observed in females. In contrast, a strong negative correlation between TSHand T2DMwas observed inmales, but not in females. Conclusions: This study demonstrated that decreased FT3, FT3/FT4 ratios, and increased FT4 levels are independently related to a higher prevalence of T2DM in both males and females, and TSH is inversely related to T2DM in males only.
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  • Rotation-Facilitated Rapid Transport of Nanorods in Mucosal Tissues

    Yu, Miaorong   Wang, Jiuling   Yang, Yiwei   Zhu, Chunliu   Su, Qian   Guo, Shiyan   Sun, Jiashu   Gan, Yong   Shi, Xinghua   Gao, Huajian  

    Mucus is a viscoelastic gel layer that typically protects exposed surfaces of the gastrointestinal (GI) tract, lung airways, and other mucosal tissues. Particles targeted to these tissues can be efficiently trapped and removed by mucus, thereby limiting the effectiveness of such drug delivery systems. In this study, we experimentally and theoretically demonstrated that cylindrical nanoparticles. (NPs), such as mesoporous silica nanorods and calcium phosphate nanorods, have superior transport and trafficking capability in mucus compared with spheres of the same chemistry. The higher diffusivity of nanorods leads to deeper mucus penetration and a longer retention time in the GI tract than that of their spherical counterparts. Molecular simulations and stimulated emission of depletion (STED) microscopy revealed that this anomalous phenomenon can be attributed to the rotational dynamics of the NPs facilitated by the mucin fibers and the shear flow. These findings shed new light on the shape design of NP-based drug delivery systems targeted to mucosal and tumor sites that possess a fibrous structure/porous medium.
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  • Study on the Heat of Hydration and Strength Development of Cast-In-Situ Foamed Concrete

    Zhao, Wenhui   Su, Qian   Han, Feng   Wang, Wubin  

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  • Impact of COMT haplotypes on functional connectivity density and its association with the gene expression of dopamine receptors

    Tang, Jie   Li, Yanjun   Xu, Jiayuan   Qin, Wen   Su, Qian   Xu, Qiang   Liu, Bing   Jiang, Tianzi   Yu, Chunshui  

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  • Tailoring Molecular Weight of Bioderived Polycarbonates via Bifunctional Ionic Liquids Catalysts under Metal-Free Conditions

    Ma, Congkai   Xu, Fei   Cheng, Weiguo   Tan, Xin   Su, Qian   Zhang, Suojiang  

    Synthesis of bioderived high-molecular-weight polycarbonates over metal-free catalysts is of great importance but also challenging. In this work, a series of 1-butyl-3-methylimidazolium (Bmim) ionic liquids (ILs) were prepared as catalysts for a melt polycondensation reaction of isosorbide and diphenyl carbonate. By modifying the structures of ILs' anions, the number-average molecular weight (M-n) of poly(isosorbide carbonate) (PIC) was effectively tailored. In the presence of a trace amount (0.05 mol % based on isosorbide) of bifunctional [Bmim][CH3CHOHCOO], the synthesized PIC possessed high M-n of 61,700 g/mol and a glass transition temperature of 174 degrees C, both the highest so far to the best of our knowledge. Besides, it was found that the anions with stronger electronegativity and hydrogen bond formation ability were more efficient for the formation of PIC with higher M-n. To modify the flexibility of PIC, poly(aliphatic diol-co-isosorbide carbonate)s with M-n ranging from 34,000 to 75,700 g/mol were also formulated by incorporating with various aliphatic diols. Additionally, based on the experimental results and nuclear magnetic resonance spectroscopy, a possible mechanism of cooperative nucleophilic-electrophilic activation through hydrogen bond formation and electrostatic interactions by the ILs catalyst was proposed.
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  • Overexpression of a bifunctional enzyme, CrtS, enhances astaxanthin synthesis through two pathways in Phaffia rhodozyma.

    Chi, Shuang   He, Yanfeng   Ren, Jie   Su, Qian   Liu, Xingchao   Chen, Zhi   Wang, Mingan   Li, Ying   Li, Jilun  

    BACKGROUND: A moderate-temperature, astaxanthin-overproducing mutant strain (termed MK19) of Phaffia rhodozyma was generated in our laboratory. The intracellular astaxanthin content of MK19 was 17-fold higher than that of wild-type. The TLC profile of MK19 showed a band for an unknown carotenoid pigment between those of beta-carotene and astaxanthin. In the present study, we attempted to identify the unknown pigment and to enhance astaxanthin synthesis in MK19 by overexpression of the crtS gene that encodes astaxanthin synthase (CrtS).; RESULTS: A crtS-overexpressing strain was constructed without antibiotic marker. A recombinant plasmid with lower copy numbers was shown to be stable in MK19. In the positive recombinant strain (termed CSR19), maximal astaxanthin yield was 33.5% higher than MK19, and the proportion of astaxanthin as a percentage of total carotenoids was 84%. The unknown carotenoid was identified as 3-hydroxy-3',4'-didehydro-beta,Psi-carotene-4-one (HDCO) by HPLC, mass spectrometry, and NMR spectroscopy. CrtS was found to be a bifunctional enzyme that helped convert HDCO to astaxanthin. Enhancement of crtS transcriptional level increased transcription levels of related genes (crtE, crtYB, crtI) in the astaxanthin synthesis pathway. A scheme of carotenoid biosynthesis in P. rhodozyma involving alternative bicyclic and monocyclic pathways is proposed.; CONCLUSIONS: CrtS overexpression leads to up-regulation of synthesis-related genes and increased astaxanthin production. The transformant CSR19 is a stable, secure strain suitable for feed additive production. The present findings help clarify the regulatory mechanisms that underlie metabolic fluxes in P. rhodozyma carotenoid biosynthesis pathways.=20
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