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Search Results: 1 - 10 of 78259 matches for " Kangkang Chen "
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China and India Trade Competition and Complementary: Analysis of the “Belt and Road” Background  [PDF]
Kangkang Li
Modern Economy (ME) , 2018, DOI: 10.4236/me.2018.97079
Abstract: In recent years, bilateral relations between China and India are the focus of international attention. Despite the constant friction between China and India, the fact that China is the largest trade partner in India is not changed, and the bilateral trade volume in 2017 has set a new record of history. The continued implementation of the strategy of “One Belt and One Road” of the Chinese government has brought lots of new opportunities for China and India economic and trade cooperation. In order to analyze the competitiveness and complementarity of trade between China and India under the background of “One Belt and One Road”, the article uses the “UN” UNCOMTRADE database, measuring the trade of China and India of revealed comparative advantage index, trade integration index, export similarity index, the specialization of the revised coefficient index and coefficient of consistent index, to analyze competition and complementarity of trade between China and India. Results show that the trade structure of China and India has a certain competition, but also has a lot of complementarity; There are many types of products in mutual trade: China mainly exports manufactured goods to India, and the India exports to China mainly primary products and semi-finished products. According to the strategy of “One Belt and One Road” background, we try to put forward policy measures to promote China’s economic and trade relations with south India.
Double Cladding Seven-core Photonic Crystal Fiber  [PDF]
Gelin Zhang, Fengfei Xing, Peiguang Yan, Huifeng Wei, Huiquan Li, Shisheng Huang, Rongyong Lin, Kangkang Chen
Optics and Photonics Journal (OPJ) , 2013, DOI: 10.4236/opj.2013.32B011

A double cladding seven-core PCF was presented for high power supercontinuum generation. The calculated zero dispersion wavelength is located at 912 nm, which has a good agreement with the measurement. The attenuation is measured 6 dB/km at 1590 nm and lower than 14.5 dB/km at 1060 nm, the water-loss peak at 1380 nm is about 134 dB/km; Supercontinuum spanning over more than 1500 nm was generated when the designed seven-core PCF was pumped by a gain-switching Yetterbium-doped fiber laser. These results will be helpful in the future design of multicore photonic crystal fibers (MCPCF) with proper guidance properties for high power supercontinuum generation.

One Case about the Diagnosis and Treatment of Right-Sided Infective Endocarditis without Any Inducement  [PDF]
Shengsen Chen, Kangkang Yu, Qingxia Ling, Chong Huang, Jianming Zheng, Qi Cheng, Mengqi Zhu, Ning Li, Mingquan Chen
Case Reports in Clinical Medicine (CRCM) , 2014, DOI: 10.4236/crcm.2014.312134
Abstract: We present a case of Staphylococcus aurous tricuspid valve endocarditis without any risk factors (intravenous drug users, with pacemaker or central venous lines and with congenital heart disease). Transthoracic echocardiography, as first line examination, showed the vegetations on tricuspid valve. In our case, the diagnosis and treatment of right-sided infective endocarditis without any inducement were extremely difficult. Therefore, once a patient comes out with fever, the blood culture remains positive for gram-positive bacterium, and the infectious location still unknown, then the infective endocarditis should be considered. In addition, surgical measure is also an important therapy for right-sided infective endocarditis.
Role of amino acid residues involved in the active cavity of proline iminopeptidase in catalytic activity  [PDF]
Kangkang Xing, Hong Feng
Advances in Biological Chemistry (ABC) , 2013, DOI: 10.4236/abc.2013.33032
Abstract: The proline iminopeptidase (PchPiPA) of the white-rot fungi Phanerochaete chrysosporium is an exopeptidase specific to catalyze hydrolysis of the N-terminal proline of peptides or proteins. Its catalytic cavity is comprised of a catalytic triad (Ser107, Asp264 and His292) and an oxyanion hole (His38, Gly39, Gly40 and Pro41). In this work, several amino acid residues involved in the catalytic cavity were selected for investigation of their influences on the catalytic activity by site-directed mutagenesis. It was shown that mutation of residues (Gly39 and Gly40) involved in oxyanion hole resulted in almost complete loss of catalytic activity largely due to changes in kcat. The other residues (Gly42 and Cys45) lined at the entrance of the active cavity also yielded a profound negative effect on the activity. Mutation of the other two residues Arg130 and Gly131 which were flanked spatially by the nucleophilic attacking active site of Ser107, caused different effects on the activity. R130Aincreased catalytic efficiency due to changes in both kcat and Km; while G131V decreased the value of kcat/Km mainly due to changes in kcat. And T111Aalso caused a negative effect on the kcat. Conclusively, these amino acid residues involved in active cavity were more susceptible to be negatively affected by mutation, suggested that the active cavity of proline iminopeptidase might evolve to be less plausible.
The order of expression is a key factor in the production of active transglutaminase in Escherichia coli by co-expression with its pro-peptide
Song Liu, Dongxu Zhang, Miao Wang, Wenjing Cui, Kangkang Chen, Guocheng Du, Jian Chen, Zhemin Zhou
Microbial Cell Factories , 2011, DOI: 10.1186/1475-2859-10-112
Abstract: A TGase from S. hygroscopicus was expressed in E. coli only after fusing with the pelB signal peptide, but fusion with the signal peptide induced insoluble enzyme. Therefore, alternative protocol was designed by co-expressing the TGase and its pro-peptide as independent polypeptides under a single T7 promoter using vector pET-22b(+). Although the pro-peptide was co-expressed, the TGase fused without the signal peptide was undetectable in both soluble and insoluble fractions of the recombinant cells. Similarly, when both genes were expressed in the order of the TGase and the pro-peptide, the solubility of TGase fused with the signal peptide was not improved by the co-expression with its pro-peptide. Interestingly, active TGase was only produced by the cells in which the pro-peptide and the TGase were fused with the signal peptide and sequentially expressed. The purified recombinant and native TGase shared the similar catalytic properties.Our results indicated that the pro-peptide can assist correct folding of the TGase inter-molecularly in E. coli, and expression of pro-peptide prior to that of TGase was essential for the production of active TGase. The co-expression strategy based on optimizing the order of gene expression could be useful for the expression of other functional proteins that are synthesized as a precursor.Transglutaminase (EC, TGase) catalyzes crosslinking between the γ-carboxyamide groups of glutamine residues (acyl donors) and a variety of primary amines (acyl acceptors) in many proteins [1]. In the absence of primary amines, H2O can act as an acyl acceptor, resulting in the deamidation of glutamine residues [1]. Multifunctional TGases are widely found in mammals [2], plants [3], and microorganisms [1]. Since the first microbial TGase was discovered in Streptomyces mobaraensis [4], and many other TGase-producing microbial strains have been identified [5]. The Streptomyces TGase has been widely applied in the food industry to improve the fu
Detection of Hepatitis B virus in serum and liver of chickens
Jijing Tian, Kangkang Xia, Ruiping She, Wengui Li, Ye Ding, Jiande Wang, Mingyong Chen, Jun Yin
Virology Journal , 2012, DOI: 10.1186/1743-422x-9-2
Abstract: Hepatitis B virus (HBV) is one of the most important human pathogens. More than 350 million people worldwide are persistently infected with HBV and are at risk of developing chronic liver disease, cirrhosis and hepatocellular carcinoma [1]. While vertical transmission of HBV from mother to neonate always results in chronic hepatitis, infection during adulthood results in lifelong protective immunity [2]. Although measures such as vaccination have been taken for years, the prevalence of HBV has not been controlled effectively, and it is still a major threat to human health.The HBV genome is a relaxed circular DNA of ~ 3 200 nucleotides and consists of full length of the negative strand and a shorter positive strand. Serologic markers of hepatitis B virus infection include both viral antigens (surface antigen, HBsAg, and e antigen, HBeAg) and antibodies (anti-HBs, anti-HBc, anti-HBe). HBsAg is the most frequently used to screen for the presence of HBV infection. The presence of HBeAg in a host's serum is associated with much higher rates of viral replication and enhanced infectivity [3]. Detection of all the serologic markers is meaningful for clinical diagnosis of HBV in human.Infection of HBV has already been documented in non-human primates (NHPs)[4] such as chimpanzees [5,6] and gorillas [7,8] in sub-Saharan Africa; gibbons and orangutans in South-East Africa [7,9]. Epidemiological studies have shown a high prevalence of HBV infection in great apes, that is comparable to human population in Gabon and Congo [7]. Furthermore, our team has found the existence of HBV in swine [10], indicating the possibility of HBV infection in food animals. Although there is currently no evidence that human population have been or are infected with food animal-associated HBV variants, existence of HBV in food animals deserves greater attention from researchers and the general public. Chickens are widely consumed by people all over the world, but it is not clear whether chickens have
Study on mechanism and kinetics of ammonia-nitrogen removal by ultrasound stripping

Peng Renyong,Chen Kangkang,Li Yanlin,

环境工程学报 , 2010,
Abstract: 采用超声吹脱技术对某印染厂印染废水中的氨氮进行了处理实验,探索了其反应机理并进行了动力学研究。研究表明,叔丁醇的存在没有降低废水中氨氮的去除率,证明·OH不是超声吹脱去除氨氮反应中的主导氧化物种。通过对反应产物的分析发现,超声吹脱去除氨氮的机理主要是氨氮以游离态的方式在空化效应下高温高压热解成氮气和氢气排出,同时氨气在空化效应产生的超临界状态下传质速度加快,在吹脱条件下更易于从废水中散失。动力学分析表明,印染废水中氨氮的超声去除反应属于一级反应,符合一级反应动力学。
Dynamic Analysis of Water Resources Supply- demand Balance about Mining Cities in Central Liaoning

GU Kangkang,LIU Jingshuang,CHEN Xin,

地理学报 , 2008,
Abstract: The mining cities in central Liaoning region are important energy production and heavy industry base in China. It is important to conduct research on their water resources supply-demand change. The framework of water resources supply-demand balance, the calculation of both useable water resources and water resource demand, and the influencing factors of water resources supply-demand balance were analyzed. Results showed that: from 1997 to 2005, the regional differences of water resources supply-demand balance among the mining cities in central Liaoning region were evident. The water resources supply-demand in Anshan was notably unbalanced, while the lack of water resources was declining, which was 0.32 ×108 m3 in 2005; the supply-demand of water resources in Fushun kept balance on the whole, the surplus of water resources was increasing, which was 5.25 ×108 m3 in 2005; for Benxi the water resources supply-demand was balanceable, the available water resources exceeded the water resource demand each year, the surplus of water resource was 8.65×108 m3 in 2005. The utilization rate of water resources in Anshan was 65.56%, while the degree of water demand was highly intense; the utilization rate of water resources in Fushun was 35.11%, while the degree of water demand was moderately highly intense; for Benxi the utilization rate of water resources was 27.96% , while the degree of water demand was moderately highly intense. The structures of water resource demand were also different among mining cities in central Liaoning region. In Anshan, the water demand of agriculture and eco-environment were primary, which accounted for 76% of the total; in Fushun, the eco-environment water demand was most significant, which accounted for 60% , the agriculture water demand accounted for only 23%; in Benxi, eco-environment water demand accounted for 67%, while industrial water demand accounted for only 15%.
Some Shannon-McMillan Approximation Theorems for Markov Chain Field on the Generalized Bethe Tree
Kangkang Wang,Decai Zong
Journal of Inequalities and Applications , 2011, DOI: 10.1155/2011/470910
Some Shannon-McMillan Approximation Theorems for Markov Chain Field on the Generalized Bethe Tree
Wang Kangkang,Zong Decai
Journal of Inequalities and Applications , 2011,
Abstract: A class of small-deviation theorems for the relative entropy densities of arbitrary random field on the generalized Bethe tree are discussed by comparing the arbitrary measure with the Markov measure on the generalized Bethe tree. As corollaries, some Shannon-Mcmillan theorems for the arbitrary random field on the generalized Bethe tree, Markov chain field on the generalized Bethe tree are obtained.
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