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Search Results: 1 - 10 of 17962 matches for " DuoHong Sheng "
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Co-expression with RadA and the characterization of stRad55B, a RadA paralog from the hyperthermophilic crenarchaea Sulfolobus tokodaii
DuoHong Sheng,MingFeng Li,JianDong Jiao,JinFeng Ni,YuLong Shen
Science China Life Sciences , 2008, DOI: 10.1007/s11427-008-0008-x
Abstract: ST0838 (designed stRad55B) is one of the four RadA paralogs (or Rad55 homologues) in the genome of the hyperthermophilic crenarchaeon Sulfolobus tokodaii. The gene is induced by UV irradiation, suggesting that it is involved in DNA recombinational repair in this organism. However, this protein could not be expressed normally in vitro. In this study, thermostable and soluble stRad55B was obtained by co-expression with S. tokodaii RadA (stRadA) in E. coli, and the enzymatic properties were examined. It was found that stRad55B bound ssDNA preferentially and had a very weak ATPase activity that was not stimulated by DNA. The recombinant protein inhibited the strand exchange activity promoted by stRadA, indicating that stRad55B might be an inhibitor to the homologous recombination in this archaeon. The results will be helpful for further functional and interaction analysis of RadA paralogs and for the understanding of the mechanism of recombinational repair in archaea.
Sulfolobus tokodaii RadA paralog, stRadC2, is involved in DNA recombination via interaction with RadA and Hjc
Lei Wang,DuoHong Sheng,WenYuan Han,Bin Huang,ShanShan Zhu,JinFeng Ni,Jia Li,YuLong Shen
Science China Life Sciences , 2012, DOI: 10.1007/s11427-012-4292-0
Abstract: Rad51/RadA paralogs found in eukaryotes and euryarchaea play important roles during recombination and repair, and mutations in one of the human Rad51 paralogs, Rad51C, are associated with breast and ovarian cancers. The hyperthermophilic crenarchaeon Sulfolobus tokodaii encodes four putative RadA paralogs and studies on these proteins may assist in understanding the functions of human Rad51 paralogs. Here, we report the biochemical characterization of stRadC2, a S. tokodaii RadA paralog. Pull-down assays revealed that the protein was able to interact with the recombinase, RadA, and the Holliday junction endonuclease, Hjc. stRadC2 inhibited the strand exchange activity of RadA and facilitated Hjc-mediated Holliday junction DNA cleavage in vitro. RT-PCR analysis revealed that stRadC2 transcription was immediately reduced after UV irradiation, but was restored to normal levels at the late stages of DNA repair. Our results suggest that stRadC2 may act as an antirecombination factor in DNA recombinational repair in S. tokodaii.
Cloning, expression and radiation inducibility of RadA from the hyperther-mophilic archaeon Sulfolobus tokodaii
超嗜热古菌Sulfolobus tokodaii RadA蛋白的克隆表达及 其辐射可诱导性

Duohong Sheng,Shanshan Zhu,Mingfeng Li,Jiandong Jiao,Jinfeng Ni,Yulong Shen,
盛多红
,朱珊珊,李铭峰,焦建东,倪金凤,申玉龙

微生物学报 , 2008,
Abstract: RecA/Rad51/RadA家族蛋白是细胞内重要的重组修复蛋白,在功能上非常保守.研究发现在细菌、真核生物、甲烷古菌和嗜盐古菌细胞内RecA/Rad51/RadA均可以受紫外线辐射诱导转录.而对极端嗜热古菌中的RadA辐射可诱导性仍存在争议.通过体外表达极端嗜热古菌Sulfolobus tokodaii的RadA蛋白,制备抗体,利用免疫学方法并结合RT-PCR分析,对嗜热古菌S.tokodaii中RadA的辐射诱导进行了研究.经过100J/m2和200J/m2 UV辐照处理,radA基因的转录分别上调了2倍和3倍,同时RadA蛋白的表达分别上升了1.5倍和1倍.实验结果表明S.tokodaii中RadA可以被紫外线辐射诱导表达,证实了极端嗜热古菌S.tokodaii细胞中存在DNA损伤诱导反应的观点.
Hypoxia-Inducible Factor-1α: A Potential Factor for the Enhancement of Osseointegration between Dental Implants and Tissue-Engineered Bone
Duohong Zou,Siheng Zhu,Jian Zhou,Jian Zhou
Dental Hypotheses , 2011,
Abstract: Introduction: Tissue-engineered bones are widely utilized to protect healthy tissue, reduce pain, and increase the success rate of dental implants. one of the most challenging obstacles lies in obtaining effective os-seointegration between dental implants and tissue-engineered structures. Deficiencies in vascularization, osteogenic factors, oxygen, and other nutrients inside the tissue-engineered bone during the early stages following implantation all inhibit effective osseointe-gration. Oxygen is required for aerobic metabolism in bone and blood vessel tissues, but oxygen levels inside tissue-engineered bone are not suf-ficient for cell proliferation. HIF-1α is a pivotal regulator of hypoxic and ischemic vascular responses, driving transcriptional activation of hundreds of genes involved in vascular reactivity, angiogenesis, arteriogenesis, and osteogenesis.The hypothesis: Hypoxia-Inducible Factor-1α seems a potential factor for the enhancement of osseointegration between dental implants and tissue-engineered bone.Evaluation of the hypothesis: Enhancement of HIF-1α protein expression is recognized as the most promising approach for angiogenesis, because it can induce multiple angiogenic targets in a coordinated manner. Therefore, it will be a novel potential therapeutic methods targeting HIF-1α expression to enhance osseointegration be-tween dental implants and tissue-engineered bone.
Gearbox Scheme in High Temperature Reactor Helium Gas Turbine System  [PDF]
Sheng Liu, Xuanyu Sheng
World Journal of Nuclear Science and Technology (WJNST) , 2012, DOI: 10.4236/wjnst.2012.23014
Abstract: Helium Turbine is used in High Temperature Reactor Helium Gas Turbine (HTR-GT) system, by which the direct helium circulation between the reactor and turbine generator system will come true. Between helium turbine and generator, there is gearbox device which reduces the turbine rotation speed to normal speed required by the generator. Three optional gearbox schemes are discussed. The first is single reduction cylindrical gearbox, which consists of one high speed gear and one low speed gear. Its advantage is simple structure, easy to manufacture, and high reliability, while its disadvantage is large volume and misalignment of input and output axle. The second is planetary gear mechanism with static planet carrier. The third is planetary gear mechanism with static internal gear. The latter two gearbox devices have similar structure. Their advantage is small volume and high reduction gear ratio, while disadvantage are complicated structure, many gears, low reliability and low mechanical efficiency.
The Bone-Forming Effects of HIF-1α-Transduced BMSCs Promote Osseointegration with Dental Implant in Canine Mandible
Duohong Zou, Jiacai He, Kai Zhang, JieWen Dai, Wenjie Zhang, Shaoyi Wang, Jian Zhou, Yuanliang Huang, Zhiyuan Zhang, Xinquan Jiang
PLOS ONE , 2012, DOI: 10.1371/journal.pone.0032355
Abstract: The presence of insufficient bone volume remains a major clinical problem for dental implant placement to restore the oral function. Gene-transduced stem cells provide a promising approach for inducing bone regeneration and enhancing osseointegration in dental implants with tissue engineering technology. Our previous studies have demonstrated that the hypoxia-inducible factor-1α (HIF-1α) promotes osteogenesis in rat bone mesenchymal stem cells (BMSCs). In this study, the function of HIF-1α was validated for the first time in a preclinical large animal canine model in term of its ability to promote new bone formation in defects around implants as well as the osseointegration between tissue-engineered bone and dental implants. A lentiviral vector was constructed with the constitutively active form of HIF-1α (cHIF). The ectopic bone formation was evaluated in nude mice. The therapeutic potential of HIF-1α-overexpressing canine BMSCs in bone repair was evaluated in mesi-implant defects of immediate post-extraction implants in the canine mandible. HIF-1α mediated canine BMSCs significantly promoted new bone formation both subcutaneously and in mesi-implant defects, including increased bone volume, bone mineral density, trabecular thickness, and trabecular bone volume fraction. Furthermore, osseointegration was significantly enhanced by HIF-1α-overexpressing canine BMSCs. This study provides an important experimental evidence in a preclinical large animal model concerning to the potential applications of HIF-1α in promoting new bone formation as well as the osseointegration of immediate implantation for oral function restoration.
Prenatal Exposure to Organophosphate Pesticides and Neurobehavioral Development of Neonates: A Birth Cohort Study in Shenyang, China
Ying Zhang, Song Han, Duohong Liang, Xinzhu Shi, Fengzhi Wang, Wei Liu, Li Zhang, Lixin Chen, Yingzi Gu, Ying Tian
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0088491
Abstract: Background A large amount of organophosphate pesticides (OPs) are used in agriculture in China every year, contributing to exposure of OPs through dietary consumption among the general population. However, the level of exposure to OPs in China is still uncertain. Objective To investigate the effect of the exposure to OPs on the neonatal neurodevelopment during pregnancy in Shenyang, China. Methods 249 pregnant women enrolled in the Central Hospital Affiliated to Shenyang Medical College from February 2011 to August 2012. A cohort of the mothers and their neonates participated in the study and information on each subject was obtained by questionnaire. Dialkyl phosphate (DAP) metabolites were detected in the urine of mothers during pregnancy to evaluate the exposure level to OPs. Neonate neurobehavioral developmental levels were assessed according to the standards of the Neonatal Behavioral Neurological Assessment (NBNA). Multiple linear regressions were utilized to analyze the association between pregnancy exposure to OPs and neonatal neurobehavioral development. Results The geometric means (GM) of urinary metabolites for dimethyl phosphate (DMP), dimethyl thiophosphate (DMTP), diethyl phosphate (DEP), and diethyl thiophosphate (DETP) in pregnant women were 18.03, 8.53, 7.14, and 5.64 μg/L, respectively. Results from multiple linear regressions showed that prenatal OP exposure was one of the most important factors affecting NBNA scores. Prenatal total DAP concentrations were inversely associated with scores on the NBNA scales.?Additionally, a 10-fold increase in DAP concentrations was associated with a decrease of 1.78 regarding the Summary NBNA (95% CI, ?2.12 to ?1.45). And there was an estimated 2.11-point difference in summary NBNA scores between neonates in the highest quintile of prenatal OP exposure and the lowest quintile group. Conclusion The high exposure of pregnant women to OPs in Shenyang, China was the predominant risk factor for neonatal neurobehavioral development.
A Semantic Vector Retrieval Model for Desktop Documents  [PDF]
Sheng Li
Journal of Software Engineering and Applications (JSEA) , 2009, DOI: 10.4236/jsea.2009.21009
Abstract: The paper provides a semantic vector retrieval model for desktop documents based on the ontology. Comparing with traditional vector space model, the semantic model using semantic and ontology technology to solve several problems that traditional model could not overcome such as the shortcomings of weight computing based on statistical method, the expression of semantic relations between different keywords, the description of document semantic vectors and the similarity calculating, etc. Finally, the experimental results show that the retrieval ability of our new model has significant improvement both on recall and precision.
Orthogonal-Least-Squares Forward Selection for Parsimonious Modelling from Data  [PDF]
Sheng CHEN
Engineering (ENG) , 2009, DOI: 10.4236/eng.2009.12008
Abstract: The objective of modelling from data is not that the model simply fits the training data well. Rather, the goodness of a model is characterized by its generalization capability, interpretability and ease for knowledge extraction. All these desired properties depend crucially on the ability to construct appropriate parsimonious models by the modelling process, and a basic principle in practical nonlinear data modelling is the parsimonious principle of ensuring the smallest possible model that explains the training data. There exists a vast amount of works in the area of sparse modelling, and a widely adopted approach is based on the linear-in-the-parameters data modelling that include the radial basis function network, the neurofuzzy network and all the sparse kernel modelling techniques. A well tested strategy for parsimonious modelling from data is the orthogonal least squares (OLS) algorithm for forward selection modelling, which is capable of constructing sparse models that generalise well. This contribution continues this theme and provides a unified framework for sparse modelling from data that includes regression and classification, which belong to supervised learning, and probability density function estimation, which is an unsupervised learning problem. The OLS forward selection method based on the leave-one-out test criteria is presented within this unified data-modelling framework. Examples from regression, classification and density estimation applications are used to illustrate the effectiveness of this generic parsimonious modelling approach from data.
Anaerobic Membrane Bioreactors (AnMBR) for Wastewater Treatment  [PDF]
Sheng Chang
Advances in Chemical Engineering and Science (ACES) , 2014, DOI: 10.4236/aces.2014.41008
Abstract:

This paper focuses on the recent research in the development of anaerobic membrane bioreactors in wastewater treatment. Anaerobic wastewater treatment technology is gaining increasing attention due to its capacity to convert wastewater BODs to usable biogas with relatively low energy consumption. The anaerobic membrane bioreactor (AnMBR), which is a combination of the anaerobic biological wastewater treatment process and membrane filtration, represents a recent development in the high-rate anaerobic bioreactors. This paper reviews applications and performances of AnMBR and the membrane filtration behaviour in AnMBRs.

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