OALib Journal期刊

ISSN: 2333-9721




2018 ( 57 )

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2015 ( 537 )


匹配条件: “ Chao Qian” ,找到相关结果约18596条。
Carbohydrate-Derived Organocatalysts for the Reduction of Imines with Trichlorosilane  [PDF]
Xin Ge, Chao Qian, Xinzhi Chen
Journal of Materials Science and Chemical Engineering (MSCE) , 2015, DOI: 10.4236/msce.2015.36008

The backbone of D-glucosamine hydrochloride was fine-tuned and modified by protecting the hydroxyl groups. In order to reduce imines with trichlorosilane, the carbohydrate-derived organocatalysts were prepared and screened. Methyl-4,6-O-benzylidene-2-amino-2-deoxy-α-D-glucopyr anoside was found as the best catalyst. The reduction was proceeded under CHCl3 as solvent at 40?C, affording 68% - 94% yield.

Exploration of the postponing mechanism that delays carcinoma onset
Chao-Nan Qian
Cancer Cell International , 2010, DOI: 10.1186/1475-2867-10-38
Abstract: Hereditary susceptibility has been increasingly recognized to be an important etiological factor in many cancers. Familial aggregation is one of the phenotypes reflecting the contribution of genetic factors in carcinogenesis [1-4]. Genetic influences on cancer onset can also present as geographic and racial aggregation in some cancers. For example, nasopharyngeal carcinoma (NPC) has the highest incidence rate in southern China and Southeast Asia in populations with similar racial/ethnic backgrounds [5,6].In a study comparing the age of cancer onset, Brandt and colleagues found that cancers in individuals with a family history occur 2.6-16.3 years earlier than in sporadic patients [7]. The early onset in familial cases is observed in a variety of malignancies, including leukemia, non-Hodgkin lymphoma, and cancers arising in the cervix, breast, nasopharynx, ovary, nervous system, colorectum, endometrium, bladder, lung, prostate, skin, stomach, and pancreas [7,8]. These findings strengthen the notion that genetic susceptibility plays an important role in the carcinogenesis of a variety of cancers.Thanks to advances in molecular technology, especially genome-wide association studies (GWAS), one could expect that in the near future susceptibility gene(s) could be identified in more malignancies [9]. However, another important question is then raised: if the genetic trait is the main culprit, why does it show up so late for the most common cancers arising in epithelial tissue, with the average age of onset being 40-70 years old even in the familial cancers, although the affected individual carries the gene(s) from day 1 of his/her life?The commonly accepted explanation for the delayed onset of cancer is that accumulation of the genetic alterations is needed for carcinogenesis. The multiple mutation theory has been widely acknowledged for tumor initiation [10]. Genetic variety inside a solid tumor correlating with different invasiveness of the cells [11] further supports t
Isoparametric functions on exotic spheres
Chao Qian,Zizhou Tang
Mathematics , 2013,
Abstract: This paper extends widely the work in \cite{GT13}. Existence and non-existence results of isoparametric functions on exotic spheres and Eells-Kuiper projective planes are established. In particular, every homotopy $n$-sphere ($n>4$) carries an isoparametric function (with certain metric) with 2 points as the focal set, in strong contrast to the classification of cohomogeneity one actions on homotopy spheres \cite{St96} ( only exotic Kervaire spheres admit cohomogeneity one actions besides the standard spheres ). As an application, we improve a beautiful result of B\'{e}rard-Bergery \cite{BB77} ( see also pp.234-235 of \cite{Be78} ).
Isoparametric foliations, a problem of Eells-Lemaire and conjectures of Leung
Chao Qian,Zizhou Tang
Mathematics , 2014,
Abstract: In this paper, two sequences of minimal isoparametric hypersurfaces are constructed via the representations of Cli?ord algebra. Based on these constructions, we give estimates on eigenvalues of the Laplacian of the focal submanifolds of isoparametric hypersurfaces with four principal curvatures in unit spheres. This part is a continuation of [TY13] and [TXY14]. In 1980, Eells and Lemaire [EL83] posed a problem to characterize the compact Riemannian manifold M for which there is an eigenmap from M to S^n with dim(M) no less than n. In 1993, Eells and Ratto emphasized again in [ER93] that it is quite natural to study eigenmaps to unit spheres. As another application of our constructions, the focal maps give rise to many examples of submersive eigenmaps from minimal isoparametric hypersurfaces to unit spheres. At last, by investigating the second fundamental forms of focal submanifolds of isoparametric hypersurfaces in unit spheres, we provide infinitely many counter examples to two conjectures of Leung [Le82] on minimal submanifolds in unit spheres. Notice that these conjectures have been proved in the case that the normal connection is flat [HV01].
Recent progress in isoparametric functions and isoparametric hypersurfaces
Chao Qian,Zizhou Tang
Mathematics , 2014,
Abstract: This paper gives a survey of recent progress in isoparametric functions and isoparametric hypersurfaces, mainly in two directions. (1) Isoparametric functions on Riemannian manifolds, including exotic spheres. The existences and non-existences will be considered. (2) The Yau conjecture on the first eigenvalues of the embedded minimal hypersurfaces in the unit spheres. The history and progress of the Yau conjecture on minimal isoparametric hypersurfaces will be stated.
Differential topology interacts with isoparametric foliations
Jianquan Ge,Chao Qian
Mathematics , 2015,
Abstract: In this note, we discuss the interactions between differential topology and isoparametric foliations, surveying some recent progress and open problems.
Information Aggregation of Group Decision-Making in Emergency Events  [PDF]
Kefan Xie, Qian Wu, Gang Chen, Chao Ji
Intelligent Information Management (IIM) , 2010, DOI: 10.4236/iim.2010.28057
Abstract: Information is a key factor in emergency management, which helps decision makers to make effective decisions. In this paper, aiming at clarifying the information aggregation laws, and according to the characteristic of emergency information, information relative entropy is applied in the information aggregation to establish the information aggregation model of emergency group decision-making. The analysis shows that support and credibility of decision rule are the two factors in information aggregation. The results of four emergency decision-making groups in case study support the analysis in the paper.
Measuring Service Value Based on Service Semantics  [PDF]
Chao Ma, Zhongjie Wang, Xiaofei Xu, Qian Wu
Journal of Service Science and Management (JSSM) , 2013, DOI: 10.4236/jssm.2013.61007

Service participants can obtain different service values through participating in multiple service solutions with the same function but different performances and these solutions are usually represented as the pre-designed service models. Whether or to what degree the service values can be implemented under the support of the pre-designed service models is as a critical criterion for evaluating and selecting the most appropriate one from these service solutions. Therefore an approach of service value measurement based on service semantics (i.e. meaning of service models) is presented in this paper. Starting from a definition of service value, we present a series of concepts (e.g. value indicators, value profit constraints, etc.) and measure them based on the pre-designed service models. This paper also defines the value dependency relationships among the corresponding service values due to the uncertainty of relationships between multiple quality parameters of service elements, and then analyzes the impact of the value dependency on service value measurement. In order to complement the discussions above, a real-world case study from ocean transportation service is conducted for demonstration.

Circulating Endothelial Progenitor Cells Decrease in Infants with Bronchopulmonary Dysplasia and Increase after Inhaled Nitric Oxide
Yuanyuan Qi, Qian Jiang, Chao Chen, Yun Cao, Liling Qian
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0079060
Abstract: Background Impairment of endothelial progenitor cells (EPCs) has been shown to contribute to the development of bronchopulmonary dysplasia (BPD). In the current study, the relationship between EPC changes of after birth and the development of BPD was investigated, and the effects of inhaled nitric oxide (iNO) on EPCs were evaluated. Methods Sixty infants with a gestational age of less than 32 weeks and a birth weight of less than 1500 g were studied. NO was administered to infants who were receiving mechanical ventilation or CPAP for at least 2 days between the ages of 7 and 21 days. EPC level was determined by flow cytometry at birth, 7, 21 and 28 days of age and 36 weeks’ postmenstrual age (PMA), before and after the iNO treatment. Plasma concentrations of vascular endothelial growth factor (VEGF), stromal cell-derived factor-1 and granulocyte-macrophage colony-stimulating factor were determined via immunochemical assay. Results Twenty-five neonates developed BPD, 35 neonates survived and did not develop BPD. EPC level was decreased on day 7 and 21 in infants who later developed BPD compared with infants that did not develop BPD. From birth to 21 days of age, BPD infants had a persistently lower VEGF concentration compared with non-BPD infants. No difference was found between the two groups at day 28 or 36 weeks PMA. In infants that later developed BPD, iNO raised the KDR+CD133+ and CD34+KDR+CD133+ EPC numbers along with increasing the level of plasma VEGF. Conclusion EPC level was reduced at 7 days of age in infants with BPD, and iNO increased the EPC number along with increasing the level of VEGF. Further studies are needed to elucidate the mechanism leading to the decrease of EPCs in infants with BPD and to investigate the role of iNO treatment in the prevention of BPD.
A Protection Method of Target Codes
Ge Hongmei,Xu Chao,Shi Qian
Computer and Information Science , 2012, DOI: 10.5539/cis.v5n6p43
Abstract: In order to protect the target codes generated by compiler, this paper puts forward a scheme combining compiler with hardware platform on the base of the existing protection method of executable code First, classify codes of C Language into four security levels to determine the protection strategies for different codes. Secondly, design and implement the corresponding encryption module ,decryption module and decompression module in VHDL Language after studying the structure and the principle of FPGA and the method of development software Thirdly, decompress and decode the target codes through FPGA modules when target codes is being executed. Run the target codes only when they are qualified. Finally, implement and simulate the scheme through FPGA. The simulation experiment verifies the correctness and effectiveness of encryption module, decryption module and decompression module.

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