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Search Results: 1 - 10 of 28554 matches for " Guoping Zhu "
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Velocity Decomposition Method for Ship Advancing in Calm Water Simulation  [PDF]
Ji Zhao, Renchuan Zhu, Guoping Miao
World Journal of Engineering and Technology (WJET) , 2017, DOI: 10.4236/wjet.2017.54B005
Abstract:
In this study, a viscous-inviscid method based on velocity decomposition is presented. The velocity of the flow field is decomposed into viscous velocity and inviscid velocity, the inviscid velocity is applied for the whole domain, which includes the damping area, and the remaining viscous velocity is just acting on a small domain around the ship hull according to the boundary layer theory. The remaining viscous velocity is computed by a modified N-S equation which coupled the inviscid part, after the inviscid velocity is obtained by solving Euler equation. The simulation of Wigley hull advancing in calm water is accomplished with present method also the decomposed velocity has been studied. The result shows the present method is robust and can be a practical method for partial viscous correction.
The Roles of Several Residues of Escherichia coli DNA Photolyase in the Highly Efficient Photo-Repair of Cyclobutane Pyrimidine Dimers
Lei Xu,Guoping Zhu
Journal of Nucleic Acids , 2010, DOI: 10.4061/2010/794782
Abstract: Escherichia coli DNA photolyase is an enzyme that repairs the major kind of UV-induced lesions, cyclobutane pyrimidine dimer (CPD) in DNA utilizing 350–450?nm light as energy source. The enzyme has very high photo-repair efficiency (the quantum yield of the reaction is ~0.85), which is significantly greater than many model compounds that mimic photolyase. This suggests that some residues of the protein play important roles in the photo-repair of CPD. In this paper, we have focused on several residues discussed their roles in catalysis by reviewing the existing literature and some hypotheses. 1. Introduction The sun gives warmth and light to the living beings on the earth. However, the ultra-violet (UV) radiation in the sunlight stimulates lesions forming in DNA. The UV-induced lesions in DNA block the replication and transcription events in the living cells, cause growth delay, mutagenesis, or lethal effects to organisms [1]. In order to survive under the sunlight, the organisms have evolved several repair mechanisms to resist the harmfulness of UV. Direct reversal by DNA photolyases is one of the mechanisms. There are two types of DNA photolyases, CPD photolyases and (6-4) photolyases, which, respectively, reverse the two major UV-induced lesions in DNA, cyclobutane pyrimidine dimers (CPD), and (6-4) photoproducts, utilizing blue or near-UV light (350–450?nm) as energy source [1–4]. CPD photolyases can be further categorized into two subclasses, class I (microbial) and class II (animal and plant), based on their amino acid sequence similarity [3, 5, 6]. Flavin adenine dinucleotide (FAD) is catalytic cofactor of all photolyases [3]. And a second cofactor, usually a derivative of folate, deazaflavin or flavin, acts as a photoantenna to increase the repair efficiency of the enzymes under limiting light conditions [3, 7–9]. The repair reactions are proposed through a photon-induced electron transfer mechanism which is supported by many model compounds studies. However, the quantum yields ( = 0.7–0.98) in the repair of pyrimidine dimers by DNA photolyase is significantly higher [3, 10–13] than those model compounds ( = 0.016–0.4) [14–16]. These results indicate that some amino acid residues of photolyases play important roles in the repair reactions. Escherichia coli DNA photolyase is a representative of them. By reviewing the existing literature and some hypotheses, we discussed the roles of some residues of E. coli photolyase in the highly efficient catalysis. This paper would provide the further insights into the catalytic mechanism of the enzyme. 2.
Establishing Multicultural-Oriented Teacher Education System: An Empirical Research on Cultural Conflicts between Teachers and Students in Tibet  [PDF]
Guoping Zheng
Open Journal of Social Sciences (JSS) , 2014, DOI: 10.4236/jss.2014.26047
Abstract: This study aimed at gaining an in-depth knowledge of cultural conflicts between Han and Tibetan teachers, between teachers and students in Tibetan Autonomous Region, then discussed and analyzed the reasons for that, and finally attempted to solve the issue by establishing culture-oriented teacher education system. This study chose Dazi Junior Middle School as the case empirical study. Data for this study were gathered through interviews, participant observations, questionnaire surveys and document analysis, to analyze the cultural conflicts and its reasons. Findings suggest that teachers are “professionals” as well as “cultural workers”, also teacher cultural buildings and works. The mission of teacher education is to preserve and establish the ecology of the cultural development of teachers to promote teacher’s self-development in the interaction of self-being and self-making culture. Therefore, Teacher education system based on multi culture in ethnic minority regions should be established to realize multi-cultural harmonious symbiosis.
Synthesis, Crystal Structure, Stacking Effect and Antibacterial Studies of a Novel Quaternary Copper (II) Complex with Quinolone
Guangguo Wu,Guoping Wang,Xuchun Fu,Longguan Zhu
Molecules , 2003, DOI: 10.3390/80200287
Abstract: The structural properties of a new copper (II) complex [Cu2(cip)2(bpy)2(pip)]·6H2O (bpy=2,2’-bipyridyl, cip=1-cyclopropyl-6-4-oxo-1,4-dihydroquinoline-3-carboxylic acid, pip= piperazinyl anion), obtained during the synthesis of the copper complex with ciprofloxacin (cpf), has been investigated. The complex crystallizes in the triclinic system, space group P-1. The cell dimensions are: a=6.874(2) ?, b= 10.761(3) ?, c= 17.969(5) ?, α =80.071(6)°, β= 85.253(6)°, γ=79.109(6)°,V=1284.5(6) ?3, and Z=2. The Cu (II) ion displays a five-coordinate square pyramidal coordination with two nitrogen donors from bpy, the 4-keto and 3-carboxylate oxygen donors of cip, and the third nitrogen atom of the pip anion occupying the fifth site. There is a stack effect between cip ring and bpy ring from another molecule, where the stacking distance is about 3.5 ?. The results of elemental analysis and FT-IR measurement are also included. Both ligand and complex were assayed against gram-positive and gram-negative bacteria by the doubling dilutions method. The complex shows the same minimal inhibitory concentration (MIC) against S. Aureus and E. Coli bacteria as the corresponding ligand.
Growth and mortality rates of yellowfin tuna, Thunnus albacares (Perciformes: Scombridae), in the eastern and central Pacific Ocean
Zhu, Guoping;Xu, Liuxiong;Dai, Xiaojie;Liu, Wei;
Zoologia (Curitiba) , 2011, DOI: 10.1590/S1984-46702011000200007
Abstract: age and growth parameters were estimated for the yellowfin tuna thunnus albacares (bonnaterre, 1788). atotal of 443 individuals were sampled from china longline fisheries in the eastern and central pacific ocean from february to november 2006. the von bertalanffy growth parameters were estimated at l∞ = 175.9 cm fork length, k = 0.52 year-1, and t0 = 0.19 year. the total mortality rate (z) was estimated to be from 1.19 to 1.93 year-1, the fishing mortality (f) and the natural mortality (m) were calculated to be 0.91 year-1 and 0.65 year-1, respectively. the rate of exploitation (u) was estimated to be 0.46. this study provides estimates of growth and mortality rate for yellowfin tuna in the eastern and central pacific ocean, which may be used as biological input parameters in future stock assessments for the oceanic region. however, age analysis with other techniques, additional validation of the size composition and stock structure are also needed.
Growth and mortality rates of bigeye tuna Thunnus obesus (Perciformes: Scombridae) in the central Atlantic Ocean
Zhu,Guoping; Xu,Liuxiong; Zhou,Yingqi; Chen,Xinjun;
Revista de Biología Tropical , 2009,
Abstract: age and growth parameters were estimated for bigeye tuna thunnus obesus lowe, 1839 sampled from china longline fisheries in the central atlantic ocean from october 2002 to july 2003 and from august 2004 to march 2005. the von bertalanffy growth parameters were estimated at l8=217.9 cm fork length, k=0.23 year-1, and t0=-0.44 year. the total mortality rate (z) was estimated to be from 0.82 to 1.02, the fishing mortality (f) and the natural mortality were 0.54 year-1 and 0.39 year-1, respectively. the exploitation ratio (e) was 0.35. this study provides the detailed estimates of growth and mortality rate for bigeye tuna in the central atlantic ocean, which can be used as biological input parameters in further stock evaluations in this region. however, age analysis, additional validation of the size composition and stock structure are needed for future studies. rev. biol. trop. 57 (1-2): 79-88. epub 2009 june 30.
Growth and mortality rates of bigeye tuna Thunnus obesus (Perciformes: Scombridae) in the central Atlantic Ocean
Guoping Zhu,Liuxiong Xu,Yingqi Zhou,Xinjun Chen
Revista de Biología Tropical , 2009,
Abstract: Age and growth parameters were estimated for bigeye tuna Thunnus obesus Lowe, 1839 sampled from China longline fisheries in the central Atlantic Ocean from October 2002 to July 2003 and from August 2004 to March 2005. The von Bertalanffy growth parameters were estimated at L8=217.9 cm fork length, k=0.23 year-1, and t0=-0.44 year. The total mortality rate (Z) was estimated to be from 0.82 to 1.02, the fishing mortality (F) and the natural mortality were 0.54 year-1 and 0.39 year-1, respectively. The exploitation ratio (E) was 0.35. This study provides the detailed estimates of growth and mortality rate for bigeye tuna in the central Atlantic Ocean, which can be used as biological input parameters in further stock evaluations in this region. However, age analysis, additional validation of the size composition and stock structure are needed for future studies. Rev. Biol. Trop. 57 (1-2): 79-88. Epub 2009 June 30.
Control of Directionality in Streptomyces Phage φBT1 Integrase-Mediated Site-Specific Recombination
Lin Zhang, Binyan Zhu, Ruixue Dai, Guoping Zhao, Xiaoming Ding
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0080434
Abstract: Streptomyces phage φBT1 integrates its genome into the attB site of the host chromosome with the attP site to generate attL and attR. The φBT1 integrase belongs to the large serine recombinase subfamily which directly binds to target sites to initiate double strand breakage and exchange. A recombination directionality factor (RDF) is commonly required for switching integration to excision. Here we report the characterization of the RDF protein for φBT1 recombination. The RDF, is a phage-encoded gp3 gene product (28 KDa), which allows efficient active excision between attL and attR, and inhibits integration between attB and attP; Gp3 can also catalyze topological relaxation with the integrase of supercoiled plasmids containing a single excision site. Further study showed that Gp3 could form a dimer and interact with the integrase whether it bound to the substrate or not. The synapse formation of attL or attR alone with integrase and Gp3 showed that synapsis did not discriminate between the two sites, indicating that complementarity of central dinucleotides is the sole determinant of outcome in correct excision synapses. Furthermore, both in vitro and in vivo evidence support that the RDFs of φBT1 and φC31 were fully exchangeable, despite the low amino acid sequence identity of the two integrases.
Isocitrate Dehydrogenase from Streptococcus mutans: Biochemical Properties and Evaluation of a Putative Phosphorylation Site at Ser102
Peng Wang, Ping Song, Mingming Jin, Guoping Zhu
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0058918
Abstract: Isocitrate deyhdrogenase (IDH) is a reversible enzyme in the tricarboxylic acid cycle that catalyzes the NAD(P)+-dependent oxidative decarboxylation of isocitrate to α-ketoglutarate (αKG) and the NAD(P)H/CO2-dependent reductive carboxylation of αKG to isocitrate. The IDH gene from Streptococcus mutans was fused with the icd gene promoter from Escherichia coli to initiate its expression in the glutamate auxotrophic strain E. coli Δicd::kanr of which the icd gene has been replaced by kanamycin resistance gene. The expression of S. mutans IDH (SmIDH) may restore the wild-type phenotype of the icd-defective strain on minimal medium without glutamate. The molecular weight of SmIDH was estimated to be 70 kDa by gel filtration chromatography, suggesting a homodimeric structure. SmIDH was divalent cation-dependent and Mn2+ was found to be the most effective cation. The optimal pH of SmIDH was 7.8 and the maximum activity was around 45°C. SmIDH was completely NAD+ dependent and its apparent Km for NAD+ was 137 μM. In order to evaluate the role of the putative phosphorylation site at Ser102 in catalysis, two “stably phosphorylated” mutants were constructed by converting Ser102 into Glu102 or Asp102 in SmIDH to mimick a constitutively phosphorylated state. Meanwhile, the functional roles of another four amino acids (threonine, glycine, alanine and tyrosine) containing variant size of side chains were investigated. The replacement of Asp102 or Glu102 totally inactivated the enzyme, while the S102T, S102G, S102A and S102Y mutants decreased the affinity to isocitrate and only retained 16.0%, 2.8%, 3.3% and 1.1% of the original activity, respectively. These results reveal that Ser102 plays important role in substrate binding and is required for the enzyme function. Also, Ser102 in SmIDH is a potential phosphorylation site, indicating that the ancient NAD-dependent IDHs might be the underlying origin of “phosphorylation mechanism” used by their bacterial NADP-dependent homologs.
A Novel Adaptive Hybrid Error Correction Scheme for Wireless DVB Services  [PDF]
Guoping TAN, Thorsten HERFET
Int'l J. of Communications, Network and System Sciences (IJCNS) , 2008, DOI: 10.4236/ijcns.2008.12023
Abstract: Real-time applications usually not only have a certain Packet Loss Ratio (PLR) requirement but also can have strict delay constraints. In the past, we proposed a Hybrid Error Correction (HEC) scheme with Packet Repetition (PR) technique for guaranteeing a certain PLR requirement under strict delay constraints. Unfortunately, the HEC-PR scheme can only work efficiently in multicast scenarios with small group size and small link PLR. Our further studies show that better performance can be obtained by combining the HEC-PR scheme with other traditional HEC schemes such as Type I HARQ and Type II HARQ techniques. Based on this idea, in this paper, a novel Adaptive HEC (AHEC) scheme combining the HEC-PR scheme with Type I and Type II HARQ techniques is proposed to satisfy a certain PLR requirement for delay bounded multicast services. Furthermore, the performance of the AHEC scheme is optimized by choosing the scheme with the least needed redundancy information automatically among the three HEC schemes. Finally, by applying the AHEC scheme in a typical wireless DVB scenario, we analyze the performances of the AHEC scheme and compare it with the HEC-PR scheme and an Adaptive Forward Error Correction (AFEC) scheme. The results show that the proposed AHEC scheme outperforms both the AFEC scheme and the HEC-PR scheme.
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