247 results on '"C Y, Zhang"'
Search Results
152. Effect of ion drift on arbitrary‐amplitude ion‐acoustic solitary waves
- Author
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C. Y. Zhang and H. H. Kuehl
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Fluid Flow and Transfer Processes ,Physics ,media_common.quotation_subject ,Computational Mechanics ,General Physics and Astronomy ,Plasma ,Electron ,Condensed Matter Physics ,Inertia ,Ion acoustic wave ,Ion ,Amplitude ,Thermal velocity ,Physics::Plasma Physics ,Mechanics of Materials ,Atomic physics ,Relativistic quantum chemistry ,Nonlinear Sciences::Pattern Formation and Solitons ,media_common - Abstract
The properties of arbitrary‐amplitude solitary waves in a plasma consisting of drifting ions and nondrifting electrons are investigated. The conditions for the existence of solitary‐wave solutions are determined. It is shown that electron inertia has the significant effect of restricting the regime of solitary waves to ion drift velocities that are less than the electron thermal speed. Because of this restriction relativistic effects are small.
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- 1991
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153. Effects of 14-deoxyandrographolide and 14-deoxy-11,12-didehydroandrographolide on nitric oxide production in cultured human endothelial cells
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B. K. H. Tan and C. Y. Zhang
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Pharmacology ,Endothelium ,Traditional medicine ,biology ,business.industry ,Biological activity ,Pharmacognosy ,In vitro ,Nitric oxide ,Nitric oxide synthase ,Endothelial stem cell ,chemistry.chemical_compound ,medicine.anatomical_structure ,chemistry ,Mechanism of action ,medicine ,biology.protein ,medicine.symptom ,business - Abstract
14-deoxyandrographolide (DA) and 14-deoxy-11,12-didehydroandrographolide (DDA) are two diterpenoids isolated from A. paniculata, a popular folk medicine used as an antihypertensive drug in Malaysia. We have previously reported that DDA exhibited a greater hypotensive effect in anaesthetized rats and a vasorelaxant activity in isolated rat aorta, compared with DA. Their vasorelaxant activities were mediated through the activation of the enzymes, nitric oxide synthase (NOS) and guanylyl cyclase. The present study demonstrated that both DA and DDA stimulated nitric oxide (NO) release from human endothelial cells. DDA compared with DA caused a greater production of NO; this is in line with the finding of the earlier study that the vasorelaxant effect of DDA was more dependent on endothelium than DA.
- Published
- 1999
- Full Text
- View/download PDF
154. Physiological and biochemical responses of in vitro Fusarium oxysporum f.sp. niveum to benzoic acid
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Gao Chen, C. Y. Zhang, Qirong Shen, Ze-sheng Mao, J. H. Wang, M. Gu, Zhu Tang, Hong-sheng Wu, Yi-hao Wang, and Yanxia Liu
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Plant Exudates ,Molecular Sequence Data ,Microbiology ,Conidium ,Citrullus ,chemistry.chemical_compound ,Fusarium ,Fusarium oxysporum ,Spore germination ,Mycotoxin ,Phylogeny ,Benzoic acid ,Plant Diseases ,biology ,food and beverages ,General Medicine ,Phenolic acid ,Benzoic Acid ,Mycotoxins ,Spores, Fungal ,biology.organism_classification ,Enzyme assay ,chemistry ,Germination ,biology.protein - Abstract
The allelopathic potential of an artificially applied allelochemical, benzoic acid, on in vitro Fusarium oxysporum f.sp. niveum (a soil-borne pathogen causing watermelon wilt) was evaluated. Benzoic acid strongly inhibited its growth, sporulation and conidia germination, whereas it stimulated virulence factors of this pathogen. The biomass was reduced by 83-96 % and the conidia germinating rate and conidia production rate were decreased by 100 % at a concentration of >200 mg/L. However, phytopathogenic enzyme activities and mycotoxin production were stimulated with an increase of 10.2-1250 % for enzyme activities and 610-2630 % for mycotoxin yield.
- Published
- 2008
155. Envelope solitary waves in nonuniform or dissipative media
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H. H. Kuehl and C. Y. Zhang
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Fluid Flow and Transfer Processes ,Physics ,Wave packet ,Computational Mechanics ,General Physics and Astronomy ,Condensed Matter Physics ,Schrödinger equation ,symbols.namesake ,Classical mechanics ,Transformation (function) ,Physics::Plasma Physics ,Mechanics of Materials ,symbols ,Dissipative system ,Perturbation theory ,Series expansion ,Nonlinear Sciences::Pattern Formation and Solitons ,Nonlinear Schrödinger equation ,Envelope (waves) - Abstract
For a weakly nonuniform medium, a solitary wave solution of the variable‐coefficient nonlinear Schrodinger equation is obtained through second order in the expansion parameter. From a generalization of the second‐order result, the form of the solution to all orders is derived from which the conditions for an exact, distortionless solitary wave in a nonuniform medium are obtained. By use of a transformation, these results are shown to apply a weakly dissipative medium.
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- 1990
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156. Effects of higher‐order dispersion on envelope solitons
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H. H. Kuehl and C. Y. Zhang
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Fluid Flow and Transfer Processes ,Physics ,Computational Mechanics ,General Physics and Astronomy ,Condensed Matter Physics ,Third derivative ,symbols.namesake ,Amplitude ,Mechanics of Materials ,Quantum mechanics ,Quantum electrodynamics ,Dispersion relation ,Dispersion (optics) ,symbols ,Soliton ,Perturbation theory ,Nonlinear Sciences::Pattern Formation and Solitons ,Nonlinear Schrödinger equation ,Envelope (waves) - Abstract
The soliton modifications resulting from the addition of a small third derivative term, due to higher‐order dispersion, to the nonlinear Schrodinger equation are investigated. Based on direct perturbation theory, it is shown that through first order, the soliton phase and velocity are modified, but the shape, amplitude, and width are unchanged. The radiation stimulated by the third derivative term, which is not predicted by the perturbation theory, is also derived. The expression obtained confirms the result of Wai (Ph.D. thesis, University of Maryland, 1988), which was obtained by a different method. The rate of change of the soliton amplitude due to this radiation, which emerges in front of the soliton, is calculated. The nonlinear term that drives the radiation is shown to grow to a value that is much larger than the unperturbed value.
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- 1990
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157. The Skew and Relative Derangements of Type $B$
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Jessica C. Y. Zhang and William Y. C. Chen
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Combinatorics ,Derangement ,Computational Theory and Mathematics ,Applied Mathematics ,Combinatorial interpretation ,Skew ,Discrete Mathematics and Combinatorics ,Inclusion–exclusion principle ,Geometry and Topology ,Intermediate structure ,Type (model theory) ,Theoretical Computer Science ,Mathematics - Abstract
By introducing the notion of relative derangements of type $B$, also called signed relative derangements, which are defined in terms of signed permutations, we obtain a type $B$ analogue of the well-known relation between the relative derangements and the classical derangements. While this fact can be proved by using the principle of inclusion and exclusion, we present a combinatorial interpretation with the aid of the intermediate structure of signed skew derangements.
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- 2007
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158. New aristolochic acid, aristololactam and renal cytotoxic constituents from the stem and leaves of Aristolochia contorta
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C Y, Zhang, X, Wang, T, Su, C M, Ma, Y J, Wen, M Y, Shang, X M, Li, G X, Liu, and S Q, Cai
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Magnetic Resonance Spectroscopy ,Plant Stems ,Spectrophotometry, Infrared ,Molecular Conformation ,Aristolochia ,Phenanthrenes ,Spectrometry, Mass, Fast Atom Bombardment ,Kidney ,Mass Spectrometry ,Cell Line ,Kidney Tubules, Proximal ,Plant Leaves ,Spectroscopy, Fourier Transform Infrared ,Aristolochic Acids ,Humans ,Spectrophotometry, Ultraviolet - Abstract
Two novel phenanthrene derivatives, aristololactam IVa (1) and 9-hydroxy aristolochic acid I (2) were isolated from the stem and leaves of Anstolochia contorta Bunge, together with 17 known compounds (3-19). The structures of these compounds were determined by spectroscopic analysis. The phenanthrenes obtained were tested for cytotoxicity against renal proximal tubular epithelial cell line (HK-2). Aristololactam IVa and 7-methoxy aristololactam IV were found to have strong cytotoxic activity against HK-2 cells with a potency similar to or even stronger than those of aristolochic acid I and aristololactam I.
- Published
- 2005
159. Andrographis paniculata and the Cardiovascular System
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Benny Kwong-Huat Tan and Amy C. Y. Zhang
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biology ,Traditional medicine ,Chemistry ,biology.organism_classification ,Andrographis paniculata - Published
- 2004
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160. Effects of sand burial on survival, growth, gas exchange and biomass allocation of Ulmus pumila seedlings in the Hunshandak Sandland, China
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Z. J. Zhang, C. Y. Zhang, J. Z. Zhang, and Longbo Shi
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Biomass (ecology) ,China ,Time Factors ,Ulmus ,Plant Transpiration ,Plant Science ,Original Articles ,Biology ,Environment ,biology.organism_classification ,Photosynthesis ,Silicon Dioxide ,Plant Roots ,Ulmus pumila ,Plant Leaves ,Root length ,Agronomy ,Seedling ,Seedlings ,Botany ,Ecosystem ,Biomass ,Water-use efficiency ,Transpiration - Abstract
• Background and Aims In the last decade, the number of young plants of Ulmus pumila in the Hunshandak Sandland has decreased sharply because of severe sand burial, and their ecological protective function has been weakened. In order to develop an understanding of the tolerance of U. pumila to sand burial and to suggest reasonable measures to protect the sparse-elm–grassland ecosystem, the effects of burial on the survival, growth, photosynthesis and biomass allocation in U. pumila were studied. • Methods Seedlings were buried at five different depths in pot experiments: no burial (control), partial burial (33 % and 67 % stem height), and complete burial (100 % and 133 % stem height). Growth analyses and measurements of photosynthesis were carried after the plants had been uncovered. • Key Results All the plants survived partial burial, but about 30 % and 80 % of the seedlings died as a result of the 100 % and 133 % sand burial treatments, respectively. The numbers of newly produced leaves and branches, and the height of the stems of the seedlings in the 33 % and 67 % burial treatments during the period of the experiment were significantly greater than those in the control. Furthermore, net photosynthetic rate, transpiration rate and water use efficiency were also elevated by the partial burial, but not affected by burial time. This might be attributed to the increased root length, which improved water acquisition. The biomass and biomass allocation of the seedlings were significantly changed by the burial treatments and burial times. The biomass was enhanced by partial burial but was reduced by complete burial at each burial time. However, the biomass allocation was not significantly changed by the 33 % and 67 % sand burial treatments 2 or 4 weeks following the burial. • Conclusions Ulmus pumila was shown to be tolerant to partial sand burial, but must be protected from complete burial.
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- 2004
161. VDR and NRAMP1 gene polymorphisms in susceptibility to pulmonary tuberculosis among the Chinese Han population: a case-control study
- Author
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W, Liu, W C, Cao, C Y, Zhang, L, Tian, X M, Wu, J D F, Habbema, Q M, Zhao, P H, Zhang, Z T, Xin, C Z, Li, and H, Yang
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Adult ,Male ,China ,Polymorphism, Genetic ,Asian People ,Genotype ,Case-Control Studies ,Humans ,Receptors, Calcitriol ,Genetic Predisposition to Disease ,Cation Transport Proteins ,Tuberculosis, Pulmonary - Abstract
To explore the potential role of vitamin D receptor (VDR) gene and natural-resistance-associated macrophage protein 1 (NRAMP1) gene polymorphisms in susceptibility to pulmonary tuberculosis (PTB) in the Chinese Han population.In an unmatched case-control study, 120 well defined PTB patients and 240 unrelated normal controls were enrolled. Information on potential risk factors of PTB was collected using a standard questionnaire. Genetic polymorphisms of VDR gene (TaqI and FokI) and NRAMP1 gene (INT4, D543N and 3'UTR) were analysed using PCR and RFLP. Unconditional logistic regression was performed, and odds ratios (ORs), their 95% confidence intervals (CI) and P values were estimated using maximum likelihood methods.Univariate analysis demonstrated that FokI-ff homozygotes, D543N G/A and 3'UTR TGTG+/del heterozygotes occurred more frequently in patients than in controls. The crude ORs were 2.345 (95%CI 1.222-4.499), 2.590 (95%CI 1.043-6.434) and 1.890 (95%CI 1.171-3.051), respectively, compared with their corresponding common genotypes. The P values were 0.033, 0.041 and 0.030, respectively. After adjusting for exposure history and BCG immunisation in the multivariate analysis, the adjusted ORs were 4.625 (95%CI 1.737-12.312), 2.415 (95%CI 1.079-8.759) and 2.187 (95%CI 1.146-4.175), with P values of 0.002, 0.036 and 0.018, respectively. Neither univariate nor multivariate analysis disclosed any significant association between the disease and TaqI or INT4.Polymorphisms in the VDR and NRAMP1 gene are statistically associated with susceptibility to PTB in the Chinese Han population.
- Published
- 2004
162. [Clinical classification and the operative curative effects of microendoscopic discectomy in the elderly lumbar disc herniation]
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Y Q, Peng, C Y, Zhang, and R S, Zhan
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Male ,Arthroscopy ,Lumbar Vertebrae ,Humans ,Female ,Middle Aged ,Intervertebral Disc Displacement ,Aged ,Diskectomy ,Follow-Up Studies ,Retrospective Studies - Abstract
To study the value of the classification of the elderly lumbar disc herniation(LDH) as an indication of microendoscopic discectomy(MED).Based on the pathological features of the elderly LDH, eighty-one patients over fifty years old (Group A) were proved to be intraspinal complications by traditional operation and were divided into I and II types which were compared with what were seen in the operation. Sixty-two patients over 50 years old (Group B) were treated with MED and reviewed retrospectively, and their curative effects were compared with their types.A general intraspinal narrowness rate of Group A was 62.07% in Type I, 107.69% in Type II (P0.01). Group B was all followed up (mean 10 months). According to the macnnab criterion, the satisfactory rate was 100% in Type I, 75% in Type II (P0.05).The clinical classification of the elderly LDH makes a significant effect on the treatment of MED, can be used as an indication of MED, and can be popularized in clinic.
- Published
- 2003
163. [Microendoscopic disectomy in the treatment of lumbar disc herniation]
- Author
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C Y, Zhang and S P, Bai
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Adult ,Male ,Lumbar Vertebrae ,Humans ,Endoscopy ,Female ,Middle Aged ,Intervertebral Disc Displacement ,Diskectomy ,Follow-Up Studies - Abstract
To investigate the clinical value of microendoscopic disectomy for the treatment of lumbosacral disc herniation(LDH).Microendoscopic disectomy (MED) technique was used to remove the nucleus and decompress the narrowed nerve root canal through an incision of 1.6 cm in length under the guidance of the "C" arm X-ray machine.Eighty-two patients with LDH underwent MED were followed up for 5 months. Eighty patients were evaluated as excellent, two as good according to the Macnab Scale.The microendoscopic disectomy can clearly expose the intervertibra and the nerve root, has little influence on the stability of the posterior structure of the spine, and can keep the spine intact. So the microendoscopic disectomy is a safe and an effective technique.
- Published
- 2003
164. A Prospective Randomized Trial to Compare the Efficacy of Tramazoline and Cocaine for Nasal Vasoconstriction before Nasal Surgery
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C.-Y. Zhang, J.-X. Zhang, Z.-Y. Li, L. Zhao, G.-L. Cao, and G. Li
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medicine.medical_specialty ,business.industry ,General Medicine ,Tramazoline ,Surgery ,law.invention ,Randomized controlled trial ,law ,Anesthesia ,Drug Discovery ,medicine ,medicine.symptom ,business ,Vasoconstriction ,Nasal surgery ,medicine.drug - Published
- 2014
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165. Effect of sodium dimercaptopropanesulfonate on antagonism of tetramethylenedisulphotetramine to GABA receptor
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C Y, Zhang, T J, Zhu, G X, Hu, X Y, Chen, D X, Liu, and Z K, Chen
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Bridged-Ring Compounds ,Male ,Antidotes ,Glycine ,Brain ,Rodenticides ,Unithiol ,Rats ,GABA Antagonists ,Rats, Sprague-Dawley ,Mice ,Random Allocation ,Receptors, GABA ,Seizures ,Animals ,Drug Interactions ,Female - Abstract
To study effects of sodium dimercaptopropanesulfonate (DMPS) on the antagonism of tetramethylenedisulphotetramine (TETS) to gamma-aminobutyric acid (GABA) receptor.Acute toxicity experiments were conducted to observe the effects of DMPS and TETS on mice. Contents of free amino acids in mouse brain were determined with automatic analyzer for amino acids. Autoradiography was used to observe the [3H]GABA bindings in the rat brain slices under different conditions.After icv and ip DMPS, the number of mice experiencing convulsions reduced from 20 in control group to 4 and 2 respectively in TETS poisoned mice. The content of GABA was altered in DMPS control group and TETS control group compared with DMPS protection group and NS control group [micromol/g: (2.09 +/- 0.05) and (2.67 +/- 0.15) vs (2.40 +/- 0.10 (micromol/g)) and (2.41 +/- 0.21)]; the content of glutamic acid was (12.3 +/- 1.2), (12.0 +/- 0.8), (10.2 +/- 0.6), and (11.8 +/- 1.0) micromol/g in NS control group, DMPS control group, TETS control group, and DMPS protection group, respectively. The OD value of autoradiograms decreased in TETS group compared with buffer control group in cortex, hippocampus, diencephalon, and brainstem [(0.084 +/- 0.008), (0.081 +/- 0.009), (0.094 +/- 0.006) and (0.081 +/- 0.006), vs (0.102 +/- 0.003), (0.109 +/- 0.005), (0.128 +/- 0.007), and (0.125 +/- 0.008), respectively]. OD value was maintained or higher than the normal level in DMPS+TETS group in the four brain areas [(0.116 +/- 0.008), (0.125 +/- 0.011), (0.129 +/- 0.005), and (0.128 +/- 0.010) vs (0.102 +/- 0.003), (0.109 +/- 0.005), (0.128 +/- 0.007), and (0.125 +/- 0.008), respectively].The inhibitory effects of DMPS on the antagonism of TETS to GABA receptor are due to the increase in the GABA binding to its receptors in brain caused by DMPS
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- 2001
166. Pharmacological actions of nerve growth factor-transferrin conjugate on the central nervous system
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G S, Liao, X B, Li, C Y, Zhang, Y Y, Shu, and S X, Tang
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Drug Carriers ,Transferrin ,Rats ,Substantia Nigra ,Mice ,Parkinsonian Disorders ,Alzheimer Disease ,Blood-Brain Barrier ,Memory ,Injections, Intravenous ,Models, Animal ,Nerve Growth Factor ,Animals ,Rats, Wistar ,Maze Learning - Abstract
Transferrin (Tf) undergoes receptor-mediated transport through the blood-brain barrier in vivo. This property allows transferrin to act as a vector for drug transport to the brain. The present investigation examines both the profile of brain delivery of nerve growth factor (NGF)-transferrin conjugate, and its therapeutic effects on CNS neurodegeneration, which affect locomotion and memory. Delivery of NGF-Tf conjugate to the brain was measured and found to be 0.075% of the injected dose per gram of brain, which is 5-fold higher than that of biotin-NGF. The increased delivery using the NGF-Tf conjugate can be attributed to an increased BBB permeability surface area product, which is about 8-fold higher than that of biotin-NGF. Intravenous injection of biotin-NGF/Tf-avidin conjugate significantly increased neuronal survival in the substantia nigra of a Parkinson's disease mouse model. In addition, this conjugate also improved recognition and memory in Alzheimer's disease rat model. In summary, these results demonstrate that using transferrin as a delivery vector is effective in targeting NGF to the central nervous system (CNS), and may optimize the therapy of age-related neurodegenerative diseases.
- Published
- 2001
167. Attenuated lapinized chinese strain of classical swine fever virus: complete nucleotide sequence and character of 3'-noncoding region
- Author
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H X, Wu, J F, Wang, C Y, Zhang, L Z, Fu, Z S, Pan, N, Wang, P W, Zhang, and W G, Zhao
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China ,Base Sequence ,Virulence ,Nucleotides ,Sequence Analysis, RNA ,Swine ,Molecular Sequence Data ,Genome, Viral ,Classical Swine Fever Virus ,Sequence Homology, Nucleic Acid ,DNA, Viral ,Animals ,Nucleic Acid Conformation ,RNA, Viral ,Rabbits ,5' Untranslated Regions ,Genetic Engineering ,3' Untranslated Regions ,Gene Library - Abstract
The complete nucleotide sequence including precise 5'- and 3'-terminal non-coding regions (NCRs) of the attenuated lapinized Chinese strain (HCLV) of Classical Swine Fever Virus (CSFV) was determined from overlapping cDNA clones constructed by separated RT-PCR and rapid amplification of cDNA ends (RACE) methods. The genomic RNA of the HCLV strain consists of 12.310 nucleotides (nts) including 374 nts and 242nts in the 5'- and 3'-NCRs, respectively. It contains one large open reading frame (ORF) encoding a polyprotein of 3,898 amino acids with a calculated molecular weight of 437.6 kDa. There is one notable insertion of 12 continuous nts, CTTTTTTCTTTT in the 3'-NCR of HCLV genomic cDNA when compared with its parental virulent Shimen strain. Sequence alignment of partial 3'-NCR reveals two groups of CSFV vaccine strains carrying similar T-rich insertions at different positions in this region. Computer-predicted secondary structures suggest that T-rich insertion greatly change the structures and thus decrease the promoter functions of 3'-NCRs during the replications of these two groups of CSFV vaccine strains.
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- 2001
168. A simple and convenient method for gaining pure populations of lymphocytes at the first mitotic division in vitro
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C.-y. Zhang and D.-q. Chen
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Adult ,Lymphocyte ,Mitosis ,Cell Separation ,Spindle Apparatus ,Biology ,chemistry.chemical_compound ,medicine ,Humans ,Colchicine ,Lymphocytes ,Metaphase ,Cells, Cultured ,Colcemid ,Demecolcine ,General Medicine ,Middle Aged ,Molecular biology ,In vitro ,medicine.anatomical_structure ,chemistry ,Gamma Rays ,Cell culture ,Immunology - Abstract
This paper describes a simple method for obtaining pure populations of human lymphocytes at the first in vitro mitotic division (M-1) by continuous treatment with colchicine or colcemid. When colchicine (7.2 x 10(-8) M) or colcemid (4.8 x 10(-8) M) was added to cultures 0-24 h after initiation, cultures harvested at 54 h had more than 99.9% of mitotic cells in the first metaphase (M-1). We showed that not only more analyzable M-1 cells may be obtained, but staining for sister-chromatid differentiation may be avoided.
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- 1992
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169. Uncoupling proteins 1 and 3 are regulated differently
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T, Hagen, C Y, Zhang, C R, Vianna, and B B, Lowell
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Uncoupling Agents ,Genetic Vectors ,Palmitates ,Membrane Proteins ,Saccharomyces cerevisiae ,Fatty Acids, Nonesterified ,Hydrogen-Ion Concentration ,Arginine ,Ion Channels ,Recombinant Proteins ,Mitochondria ,Rats ,Mitochondrial Proteins ,Oxygen Consumption ,Leucine ,Animals ,Humans ,Uncoupling Protein 3 ,Carrier Proteins ,Purine Nucleotides ,Uncoupling Protein 1 - Abstract
Using a heterologous yeast expression system, we have previously found a marked discordance between the effects of uncoupling protein (UCP) 1 and UCP3L on basal O(2) consumption in whole yeast versus isolated mitochondria. In whole yeast, UCP3L produces a greater stimulation of basal O(2) consumption, while in isolated mitochondria, UCP1 produces a much greater effect. As shown previously and in this report, UCP3L, in contrast to UCP1, is not inhibited by purine nucleotides. In the present study, we addressed two hypothetical mechanisms that could account for the observed discordance: (i) in whole yeast, purine nucleotides inhibit UCP1 but not UCP3L and (ii) preparations of isolated mitochondria lack an activator of UCP3L that is normally present in vivo. By use of a mutant of UCP1 that lacks purine nucleotide inhibition, it is demonstrated that cytosolic concentrations of purine nucleotides present in yeast effectively inhibit UCP1 activity. This suggests that the lower activity of UCP1 compared to UCP3L in whole yeast is due to purine nucleotide inhibition of UCP1 but not UCP3L. As potential activators of UCP3L we tested free fatty acids in whole yeast and isolated mitochondria. While UCP1 was strongly activated by free fatty acids, no stimulatory effect on UCP3L was observed. In summary, this study indicates that UCP1 and UCP3L differ in their regulation by purine nucleotides and free fatty acids. This different regulation may be related to different physiological functions of the two proteins.
- Published
- 2000
170. Effects of ion drift on small‐amplitude ion‐acoustic solitons
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C. Y. Zhang and H. H. Kuehl
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Fluid Flow and Transfer Processes ,Physics ,Drift velocity ,Condensed matter physics ,Computational Mechanics ,General Physics and Astronomy ,Electron ,Condensed Matter Physics ,Ion acoustic wave ,Ion ,Thermal velocity ,Physics::Plasma Physics ,Mechanics of Materials ,Stochastic drift ,Soliton ,Atomic physics ,Relativistic quantum chemistry - Abstract
Some properties of small‐amplitude ion‐acoustic solitons in a plasma consisting of nondrifting electrons and drifting ions are investigated. Electron inertia effects are shown to be considerably more important than relativistic effects. It is also shown that ion‐acoustic soliton solutions exist only if the ion drift velocity is less than the electron thermal velocity.
- Published
- 1991
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171. Effects of 14-deoxyandrographolide and 14-deoxy-11,12-didehydroandrographolide on nitric oxide production in cultured human endothelial cells
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C Y, Zhang and B K, Tan
- Subjects
Dose-Response Relationship, Drug ,Vasodilator Agents ,Malaysia ,Humans ,Endothelium, Vascular ,Diterpenes ,Nitric Oxide ,Antihypertensive Agents ,Cell Line ,Phytotherapy - Abstract
14-deoxyandrographolide (DA) and 14-deoxy-11,12-didehydroandrographolide (DDA) are two diterpenoids isolated from A. paniculata, a popular folk medicine used as an antihypertensive drug in Malaysia. We have previously reported that DDA exhibited a greater hypotensive effect in anaesthetized rats and a vasorelaxant activity in isolated rat aorta, compared with DA. Their vasorelaxant activities were mediated through the activation of the enzymes, nitric oxide synthase (NOS) and guanylyl cyclase. The present study demonstrated that both DA and DDA stimulated nitric oxide (NO) release from human endothelial cells. DDA compared with DA caused a greater production of NO; this is in line with the finding of the earlier study that the vasorelaxant effect of DDA was more dependent on endothelium than DA.
- Published
- 1999
172. Vasorelaxation of rat thoracic aorta caused by 14-deoxyandrographolide
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C. Y. Zhang and Benny K. H. Tan
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Male ,Physiology ,Muscle Relaxation ,Vasodilator Agents ,Aorta, Thoracic ,Pharmacology ,In Vitro Techniques ,Muscle, Smooth, Vascular ,Nitric oxide ,Glibenclamide ,Rats, Sprague-Dawley ,chemistry.chemical_compound ,Norepinephrine ,Phenylephrine ,Physiology (medical) ,medicine.artery ,Caffeine ,medicine ,Thoracic aorta ,Animals ,Vasoconstrictor Agents ,Cyclooxygenase Inhibitors ,Enzyme Inhibitors ,Aorta ,biology ,Rats ,Nitric oxide synthase ,chemistry ,Guanylate Cyclase ,Anesthesia ,biology.protein ,Verapamil ,Calcium ,Central Nervous System Stimulants ,Diterpenes ,Nitric Oxide Synthase ,Methylene blue ,medicine.drug - Abstract
SUMMARY 1. The pharmacological effects of 14-deoxyandrographolide on rat isolated thoracic aorta were examined. 2. 14-Deoxyandrographolide (2.5-120 μmiol/L) inhibited contractions induced by phenylephrine (PE; 0.1 μmol/L) and high K+ (80mmol/L) in a concentration-dependent manner in endothelium-intact aorta. The effect was attenuated in endo-thelium-denuded aorta without modifying the maximal response. Like verapamil, 14-deoxyandrographolide produced a much greater vasorelaxant effect in aorta precontracted by KCI than by PE. 14-Deoxyandrographolide (20-60 μmol/L) also inhibited responses of the rat aorta to PE. 3. In Ca2+-free medium (KCI 55mmol/L), 14-deoxyandrographolide (20-80 μmol/L) antagonized Ca2+-induced vasocon-traction in a concentration-dependent manner and transient contractions induced by both caffeine (10mmol/L) and noradrenaline (1μmol/L) were suppressed or almost abolished by 14-deoxyandrographolide. 4. The vasorelaxant effect of 14-deoxyandrographolide was partially antagonized by NG-nitro-L -arginine methyl ester (25 μmol/L), a specific and competitive nitric oxide synthase (NOS) inhibitor, and methylene blue (10 μmol/L), a soluble guanylate cyclase inhibitor, but was not affected by indomethacin (20 μmol/L), a cyclo-oxygenase inhibitor, or glibenclamide (10 μmol/L), an ATP-sensitive K+-channel blocker. 5. These results suggest that the vasorelaxant activity of 14-deoxyandrographolide may be mediated via the activation of NOS and guanylate cyclase, as well as the blockade of Ca2+ influx through both voltage- and receptor-operated Ca2+ channels.
- Published
- 1998
173. In vitro sensitivity of Plasmodium falciparum to eight antimalarials in China-Myanmar and China-Lao PDR border areas
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H L, Yang, D Q, Liu, Y M, Yang, K G, Huang, Y, Dong, P F, Yang, M Z, Liao, and C Y, Zhang
- Subjects
China ,Quinine ,Plasmodium falciparum ,Drug Evaluation, Preclinical ,Drug Resistance ,Amodiaquine ,Artesunate ,Chloroquine ,Microbial Sensitivity Tests ,Myanmar ,Artemisinins ,Antimalarials ,Laos ,Animals ,Humans ,Naphthyridines ,Sesquiterpenes - Abstract
In 1991-1995 by using the Rieckmann in vitro micro-method, susceptibilities of Plasmodium falciparum to eight antimalarials in the China-Lao PDR and China-Myanmar border areas were tested. The resistant rates of P. falciparum to chloroquinine were 95.0%-100%; IC50 114-240nmol/l. P. falciparum resistant rates to amodiaquine resistance accounted for 83.5%-100%, IC50 52-72nmol/l. All cases were sensitive to quinine, IC50 470-608nmol/l. P. falciparum isolates from the Lao PDR frontier were highly sensitive to artesunate, dihydroartemisinin, and arteether. Resistant rates from other areas were 0-11%. P. falciparum from China-Myanmar and Lao PDR border areas were also sensitive to mefloquine, IC50 68-88nmol/l. A longitudinal survey of the sensitivity of P. falciparum in vivo on the China-Lao PDR border showed that the average defervescent time of falciparum malaria was treated by pyronaridine increased from 32.7 +/- 16.0 hours during 1984-85 to 56.2 +/- 27.4 hours in 1995; the recrudescence rate rose up from 15.2% to 37.5%. The results monitored in vitro showed that all cases assessed in 1988 for response to pyronaridine were sensitive, but 36.4% of cases had emerging resistance, IC50 increased from 13nmol/l to 40 nmol/l. The above results suggested that P. falciparum in these areas has expressed resistance to chloroquine and amodiaquine. However, the parasites are still sensitive to artemisinin, pyronaridine, mefloquine, quinine, but with a declining sensitivities.
- Published
- 1998
174. Further characterization of thyroid hormone response elements in the human type 1 iodothyronine deiodinase gene
- Author
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C Y, Zhang, S, Kim, J W, Harney, and P R, Larsen
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Thyroid Hormones ,Binding Sites ,Receptors, Thyroid Hormone ,Base Sequence ,Sp1 Transcription Factor ,Molecular Sequence Data ,Humans ,Tretinoin ,Promoter Regions, Genetic ,Iodide Peroxidase ,Repetitive Sequences, Nucleic Acid - Abstract
The increased type 1 iodothyronine deiodinase expression in hyperthyroid patients increases the fraction of plasma T3 generated from T4 by the propylthiouracil-sensitive pathway. In this study, we extend our analysis of the thyroid hormone response elements (TREs) in the 5' flanking region of the human dio1 gene. The 5' TRE (TRE2), a direct repeat separated by 4 bp (DR+4) at -660 bp, arises from an A to G substitution in an Alu sequence, the first example of this phenomenon. An SP1 binding site immediately 5' to TRE2 increases basal expression of a 430-bp dio1 promoter-chloramphenicol acetyltransferase construct in the presence of unliganded thyroid hormone receptor, thus decreasing T3 responsiveness, but does not do so when this complex is placed in its more 5' wild-type location. The two octameric binding sites of TRE1, a retinoid X-receptor independent DR+10 structure at -90, can be exchanged or inverted without loss of T3 response potency, despite significant changes in thyroid hormone receptor binding, as assessed by gel shift assays. However, the retinoic acid response of the 716-bp dio1 5' flanking region is unaffected by elimination of TRE2 but is lost with mutations in TRE1. These findings indicate the importance of functional analyses of potential ligand-responsive transcription factors, as well as the influence of position, on TRE function and interaction with basal transcription factors. The unusual features of these TREs emphasize the need to consider alternatives to canonical half-site arrangements of receptor binding sites and contexts in the evaluation of T3- and retinoic acid-responsive genes.
- Published
- 1998
175. Crystal structure of 3'-formyl-benzo-15-crown-5, C15H20O6
- Author
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X.-X. Lei, L.-X. Zhang, C.-Y. Zhang, and H.-T. Wang
- Subjects
Inorganic Chemistry ,Crystallography ,chemistry.chemical_compound ,chemistry ,15-Crown-5 ,QD901-999 ,General Materials Science ,Crystal structure ,Condensed Matter Physics - Published
- 2006
- Full Text
- View/download PDF
176. [Leukemia inhibitory factor and its physiological functions during embryo development and blastocyst implantation]
- Author
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C Y, Zhang, E K, Duan, and G Q, Zeng
- Subjects
Embryonic and Fetal Development ,Lymphokines ,Leukemia Inhibitory Factor Receptor alpha Subunit ,Receptors, OSM-LIF ,Interleukin-6 ,Animals ,Humans ,Female ,Embryo Implantation ,Receptors, Cytokine ,Leukemia Inhibitory Factor ,Growth Inhibitors - Published
- 1997
177. Chemical Abundances and Metallicity of Planetary Nebulae
- Author
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C. Y. Zhang and Sun Kwok
- Subjects
Physics ,Abundance (ecology) ,Metallicity ,Astronomy ,Astrophysics ,Planetary nebula - Abstract
Confrontations of the dredge-up theory with observed patterns of chemical abundances of planetary nebulae (PNs) have been carried out by many authors (see, e.g., Kaler & Jacoby 1990, 1991; Stasinska & Tylenda 1990). Although these studies suggest that the observational abundance ratios of PNs can qualitatively be explained by the current dredge-up theory, scatters around the theoretical predictions in their diagrams are always large. This has led Ratag (1991) to conclude that there is no correlation at all between the nebular abundances and the core mass of CSPNs (see also Pottasch 1993).
- Published
- 1997
- Full Text
- View/download PDF
178. An Empirical Model of Morphologies of Planetary Nebulae
- Author
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Sun Kwok and C. Y. Zhang
- Subjects
Physics ,Optical image ,Very large array ,Density distribution ,Homogeneous ,Astronomy ,Astrophysics ,Imaging technique ,Planetary nebula - Abstract
The variety of different morphologies of planetary nebulae (PNs) have always fascinated researchers in the field. Recent progress in CCD imaging techniques has resulted in a large number of homogeneous optical images of more than a few hundreds PNs (Balick 1987, Schwarz, Corradi and Melnick 1992). In addition, two major radio surveys using the Very Large Array (VLA) by Aaquist and Kwok (1990, 1991) and by Zijstra, Pottasch and Bignell (1989) have revealed detailed morphologies in the radio, including many compact star-like PNs. This treasure of data sets contains useful information about morphologies, density distributions, formation and evolution of PNs, yet to be fully explored.
- Published
- 1997
- Full Text
- View/download PDF
179. Crystal structure of 3,5-dichloro-2-hydroxy-benzoic acid, C6H2Cl2(OH)COOH
- Author
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L.-X. Gao, Z.-T. Liu, C.-Y. Zhang, Z.-W. Gao, D.-H. Wu, and G.-F. Wang
- Subjects
Inorganic Chemistry ,chemistry.chemical_compound ,Crystallography ,QD901-999 ,Chemistry ,General Materials Science ,Crystal structure ,Condensed Matter Physics ,Medicinal chemistry ,Benzoic acid - Published
- 2005
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180. [Studies of murine ectoplacental cone cells interaction with laminin]
- Author
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C Y, Zhang, Y J, Cao, and G Q, Zeng
- Subjects
Mice ,Cell Movement ,Placenta ,Cell Adhesion ,Animals ,Female ,Laminin ,Peptide Fragments ,Trophoblasts - Abstract
Implantation of the mouse embryo is dependent on the interactions between the trophoblast cells and the surrounding uterine environment. The initial invasion by primary trophoblast stimulates the uterine stromal fibroblasts differentiate into decidual cells, which deposit a pericellular matrix consisting of LN, FN and Col IV. The secondary trophoblast giant cells (TGCs) from ectoplacental cone (EPC) invade the decidua to form the fetal portion of the placenta. We used synthetic peptides cyclic YIGSR (cYIGSR) and RGDS to study the mechanisms of EPC cells interaction with LN. The results indicated that cYIGSR and RGDS promoted EPC attachment and had synergistic effect, and cYIGSR also promoted EPC outgrowth and secondary TGCs migration. LN supported EPC attachment and outgrowth, as well as secondary TGCs migration from EPC. Biologically active domains RGD of LN A chain and YIGSR of LN B1 chain participated synergistically in EPC attachment, outgrowth, as well as secondary TGCs migration. Since synthetic peptides cYIGSR and RGDS can't competitively inhibit EPC attachment with LN completely, there must be other binding sites involved in the interaction.
- Published
- 1996
181. Changes in the resistance of Plasmodium falciparum to chloroquine in Hainan, China
- Author
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D Q, Liu, R J, Liu, D X, Ren, D Q, Gao, C Y, Zhang, C P, Qui, X Z, Cai, C F, Ling, A H, Song, and X, Tang
- Subjects
Adult ,China ,Adolescent ,Plasmodium falciparum ,Drug Resistance ,Chloroquine ,Middle Aged ,Antimalarials ,Child, Preschool ,parasitic diseases ,Animals ,Humans ,Malaria, Falciparum ,Child ,Research Article - Abstract
In 1979, in view of the widespread resistance of Plasmodium falciparum to chloroquine in the island of Hainan, China, it use as an antimalarial was suspended throughout the island. A longitudinal survey of the chloroquine-sensitivity of P. falciparum was carried out over the period 1981-91 to investigate whether its resistance had changed from the 1979 level. In-vitro assays were carried out every 2-3 years, while in-vivo tests were performed annually over the period 1981-83 and also in 1991. Resistance to chloroquine declined progressively after its use had stopped. The in-vitro tests indicated that the rate of chloroquine-resistant P. falciparum was 97.9% in 1981, but dropped to 60.9% in 1991 (P < 0.001). The mean concentration of chloroquine for complete inhibition of schizont formation was 10.4 pmol/microliters in 1981, but decreased to 3.0 pmol/microliters in 1991 (P < 0.001). The proportion of samples taken from malaria cases that required high concentrations ( > 6.4 pmol/microliters) of chloroquine for complete inhibition of schizont formation was 83.3% in 1981, but only 17.4% in 1991 (P < 0.001); at low concentrations ( > 1.6 pmol/microliters), the corresponding proportions increased from 4.2% in 1981 to 60.8% in 1991 (P < 0.001). In the 4-week in-vivo test, the rate of chloroquine-resistant P. falciparum decreased from 84.2% in 1981 to 40% in 1991 (P < 0.001). RII + RIII cases represented 59.4% of the total resistant cases in 1981, but decreased to 37.5% in 1991 (0.02 > P > 0.01).
- Published
- 1995
182. Two-dimensional structure of dipolar heterogeneous dumbbells
- Author
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C. Y. Zhang, X. L. Jian, and W. M. Ding
- Subjects
Physics ,Dipole ,Nuclear magnetic resonance ,Zigzag ,Monte Carlo method ,Perpendicular ,General Physics and Astronomy ,Structural transition ,Dumbbell ,Hard spheres ,Polarization (waves) ,Molecular physics - Abstract
The influence of polarization on the two-dimensional structure of heterogeneous dumbbells is studied by Monte Carlo simulation. The dumbbell consists of two fused hard spheres whose centers are embedded with point dipoles and , respectively. The axis of the dumbbell can rotate freely in the x-y plane but and are always along the x-axis which is the polarization direction. When the dipolar strength ?a is much larger than ?b, the dumbbells are perpendicular to the polarization direction and form zigzag chains; when ?a and ?b are comparable, the dumbbells will form end-to-end chains if and are parallel, or side-by-side chains if and are antiparallel. All the chains are along the polarization direction and the detailed information about them is given through extracting the radial and angular distributions from the simulation results. Finally, we calculate the energies of four kinds of ideal chains to explain structural transition. Our simulation results can explain the very recent experiment by Nagao D. et al. (Langmuir, 28 (2012) 6546) which studied the assembly of dumbbells with inducible dipoles, where magnitude of the dipoles was frequency-dependent and by changing frequency, different assemblies could be obtained.
- Published
- 2012
- Full Text
- View/download PDF
183. [Specific detection of Mycobacterium tuberculosis in clinical material by PCR and Southern blot]
- Author
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Q, Li, Y X, Pan, and C Y, Zhang
- Subjects
DNA, Bacterial ,Pleural Effusion ,Blotting, Southern ,Synovial Fluid ,Sputum ,Humans ,Tuberculosis ,Mycobacterium tuberculosis ,DNA Probes ,Polymerase Chain Reaction - Abstract
An amplified fragment of 245 base pairs from IS-986 sequence hybridized specifically with DNA of M. tuberculosis complex strains. The fragment was labelled with digoxigenin. After amplification by PCR and southern blot hybridization with the dig-labelled probe, the limit of detection of purified genomic M. tuberculosis DNA amounted to 1 fg. We detected sputum, pleural and synovial fluid with active tuberculosis by PCR and southern blot, and the sensitivities were 81.0%, 64.2% and 57.7%, respectively. From the result of the experiment, it is a very useful method for diagnosis of tuberculosis by combining PCR with Southern blot.
- Published
- 1994
184. [Longitudinal surveillance of chloroquine resistance of Plasmodium falciparum after cessation of medication in south Yunnan]
- Author
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H L, Yang, P F, Yang, Y, Dong, L G, Che, W C, Chen, H, He, D Q, Liu, R J, Liu, B, Zhan, and C Y, Zhang
- Subjects
China ,Plasmodium falciparum ,Drug Resistance ,Animals ,Chloroquine ,Longitudinal Studies - Abstract
The resistance of P. falciparum to chloroquine was assayed by in vitro microtest in 1981 and after cessation of medication in 1984, 1988-1990 and 1992 in south Yunnan Province of China. The resistance rates were 97.4% (38/39), 100% (25/25), 96.1% (73/76) and 93.7% (59/63), respectively; ID50 were 170, 132, 125 and 110 nmol/L; ID95 were 1,000, 740, 707 and 576 nmol/L; mean dosages for complete inhibition of schizont formation were 55.4, 46.7, 45.8 and 35.4 (pmol/well). A comparison of the results in 1981, 1984, 1988-1990 and 1992, the resistance rate showed no marked change, ID50 dropped 22.3% (P0.05), 26.4% (P0.05) and 35.3% (P0.01); ID95 declined 26.0% (P0.05), 29.3% (P0.05) and 42.2% (P0.01); mean dosage of inhibition dropped 15.7% (P0.05), 17.3% (P0.05) and 36.1% (P0.01). The results show that the extent of resistance in chloroquine-resistant P. falciparum to chloroquine in south Yunnan has been declined markedly, indicating that coresistance was variable and dropped along with the declining of drug pressure.
- Published
- 1994
185. [Study on correlation and clinical significance of superoxide dismutase (SOD) activity and content in 102 patients with leukemia]
- Author
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C S, Zhu, C Y, Zhang, and W Q, Weng
- Subjects
Adult ,Male ,Adolescent ,Superoxide Dismutase ,Middle Aged ,Precursor Cell Lymphoblastic Leukemia-Lymphoma ,Prognosis ,Leukemia, Lymphocytic, Chronic, B-Cell ,Hemoglobins ,Leukemia, Myeloid, Acute ,Leukocyte Count ,Leukemia, Myelogenous, Chronic, BCR-ABL Positive ,Humans ,Female ,Aged - Abstract
Serum superoxide dismutase (SOD) activity and blood Cu/Zn SOD content were examined in 102 cases of leukemia. The results showed that the total SOD activities, Cu/Zn SOD activities and contents declined significantly in blast phase of acute leukemia, yet increased to normal levels in remission. There was a positive correlation between SOD and blood hemoglobin concentration as well as leucocyte count. It declined again when leukemia recurred and in dying patients. There was a dissociation between Cu/Zn SOD activities and contents in patients with chronic granulocytic leukemia. In chronic lymphocytic leukemia, both activity and contents of SOD were normal. It was suggested that SOD plays a protective role during the occurrence and development of leukemia. SOD is a useful parameter in the differential diagnosis of leukemias and monitoring clinical course of leukemias.
- Published
- 1994
186. Dynamic light scattering from a highly swollen nonionic lamellar liquid crystal
- Author
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S. Sprunt, C. Y. Zhang, and J. D. Litster
- Subjects
Materials science ,business.industry ,Order (ring theory) ,Curvature ,Coupling (probability) ,Molecular physics ,Light scattering ,Condensed Matter::Soft Condensed Matter ,Optics ,Lamellar phase ,Liquid crystal ,Dispersion relation ,Lamellar structure ,business - Abstract
We have conducted a dynamic light-scattering study of the homeotropically aligned highly swollen lamellar phase (layer separation d\ensuremath{\sim}180 nm) of a nonionic binary system, dodecylpentaglycol (C12E5) and water, where the steric and entropic repulsion is the dominant intermembrane force stabilizing the lamellar order. We have identified a hydrodynamic mode in the two momentum-transfer limits available to light scattering. Based on previous models, we have found an explicit expression for the dispersion relation of this ``baroclinic'' or ``slip'' mode for systems with large layer spacing, which successfully explains our experimental results. When d is large, the bilayer curvature elasticity and the viscous coupling between water and the bilayers become more important to the understanding of the baroclinic mode. We found the curvature elastic constant ${\mathit{k}}_{\mathit{c}}$\ensuremath{\simeq}${\mathit{k}}_{\mathit{B}}$T, consistent with generally accepted values for flexible membranes.
- Published
- 1993
187. [Electrochemical analysis in differential diagnosis of benign and malignant oral maxillofacial tumors]
- Author
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C Y, Zhang
- Subjects
Adult ,Maxillary Neoplasms ,Adolescent ,Papilloma ,Cystadenocarcinoma ,Fibroma ,Adenocarcinoma ,Middle Aged ,Sensitivity and Specificity ,Tongue Neoplasms ,Diagnosis, Differential ,Electrochemistry ,Humans ,Mouth Neoplasms ,Child ,Aged - Abstract
A bioelectrochemical-sensor device was designed according to the principles of galvanic cell reaction. Modified bioelectrochemically, the device was used to measure the current of samples from benign and malignant tumor tissues. Statistical analysis and clinical test showed that the current values (426 microA) of the malignant tissue were higher than those (216 microA) of the benign tissue. The sensitivity and specificity were 95% and 90% respectively. This method provided important information about benignancy or malignancy of the tumor and its involvement and metastasis.
- Published
- 1993
188. Chemical Enrichment and Central Star Properties
- Author
-
C. Y. Zhang
- Subjects
Physics ,Stars ,Ionization ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics ,Star (graph theory) ,Planetary nebula ,Astrophysics::Galaxy Astrophysics - Abstract
We have selected a sample of planetary nebulae, for which the core masses are determined using distance-independent parameters (Zhang and Kwok 1992). The chemical abundances of He, N, O, and C are taken from the literature for them. Relationships of the ratios of He/H, N/O, and C/O with various stellar parameters of planetary nebulae (PN), such as the core mass, the mass of the core plus the ionized nebular gas, the stellar age and temperature, are examined. It is found that the N/O increases with increasing mass, while the C/O first increases and then decreases with the core mass. No strong correlation seems to exist between the He/H and the core mass. A correlation of the N/O and He/H with the stellar temperature exists. The current dredge-up theory for the progenitor AGB stars cannot satisfactorily account for these patterns of chemical enrichment in PN. Furthermore, the correlations of the N/O and He/H with the stellar age and temperature indicate that besides the dredge-ups in the RG and AGB stages, physical pfocesses that happen in the planetary nebula stage may also play a role in forming the observed patterns of chemical enrichment in the planetary nebulae.
- Published
- 1993
- Full Text
- View/download PDF
189. [Antipyretic and anti-inflammatory effects of Artemisia annua L]
- Author
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L, Huang, J F, Liu, L X, Liu, D F, Li, Y, Zhang, H Z, Nui, H Y, Song, and C Y, Zhang
- Subjects
Inflammation ,Male ,Pain Threshold ,Scopoletin ,Staphylococcus aureus ,Fever ,Arthritis ,Anti-Inflammatory Agents, Non-Steroidal ,Microbial Sensitivity Tests ,Rats ,Mice ,Animals ,Female ,Drugs, Chinese Herbal - Abstract
The antipyretic, heat-resisting anti-inflammatory analgesic and bacteriostasis effects of water extracts ethyl-acetate and n-butyl alcohol extracts of Artemisia annua are reported. Animal experiment has demonstrated that qinghao acid is one of the actively bacteriostatic constituents. Scopoletin is one of the anti-inflammatory constituents of Artemisia annua.
- Published
- 1993
190. On the Distances to Galactic Planetary Nebulae
- Author
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C. Y. Zhang
- Subjects
Length scale ,Physics ,Stellar mass ,Milky Way ,Astronomy ,Astrophysics ,Surface gravity ,Planetary nebula ,Luminosity ,Computational astrophysics ,Globular cluster ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
The distances are determined for 142 Galactic planetary nebulae, using two methods. Method A is based on the stellar mass and surface gravity, while Method B makes use of the stellar luminosity. These properties of the central star are inferred from the modeling of the distance-independent parameters (Zhang and Kwok 1992). The results from the two methods used in this paper are consistent with each other. A distance of 10.8 kpc is found for K648 using Method A of this work. This is in excellent agreement with the distance of 10 kpc of its hosting globular cluster M15. The distances obtained in this work are in good agreement with the distances of Mendez et al. (1992), based on the recently developed non-LTE model atmospheres including spherical extension and stellar winds. The agreement of our distances with the individually determined distances of Gathier et al. (1986a, 1986b), using the extinction-distance method and the HI 21 cm absorption method, is worse than that found between ours and Mendez et al.’s. The distances obtained by Gathier et al. are likely often to be underestimated. The various statistical distance scales, except for Cudworth’s (1974) distance scale, show no agreement with the distances determined in this work.
- Published
- 1993
- Full Text
- View/download PDF
191. Planetary Nebula Evolution Traced by Distance-Independent Parameters
- Author
-
C. Y. Zhang and Sun Kwok
- Subjects
Physics ,Nebula ,Reflection nebula ,Hertzsprung–Russell diagram ,Astronomy ,Bipolar nebula ,Astrophysics::Cosmology and Extragalactic Astrophysics ,Planetary nebula ,Protoplanetary nebula ,Stars ,symbols.namesake ,Emission nebula ,symbols ,Astrophysics::Solar and Stellar Astrophysics ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
Making use of the results from recent infrared and radio surveys of planetary nebulae, we have selected 431 nebulae to form a sample where a number of distance-independent parameters (e.g.,T b , T d , I60μm , and IRE) can be constructed. In addition, we also made use of other distance-independent parameters ne and T* where recent measurements are available. We have investigated the relationships among these parameters in the context of a coupled evolution model of the nebula and the central star. We find that most of the observed data in fact lie within the area covered by the model tracks, therefore lending strong support to the correctness of the model. Most interestingly, we find that the evolutionary tracks for nebulae with central stars of different core masses can be separated in a Tb-T* plane. This implies that the core masses and ages of the central stars can be determined completely independent of distance assumptions. The core masses and ages have been obtained for 302 central stars with previously determined central-star temperatures, We find that the mass distribution of the central stars strongly peaks at 0.6 M⊙, with 66% of the sample having masses
- Published
- 1993
- Full Text
- View/download PDF
192. Energy Distribution of Planetary Nebulae (UV to Radio)
- Author
-
C. Y. Zhang
- Subjects
Physics ,Nebula ,Reflection nebula ,Astrophysics::High Energy Astrophysical Phenomena ,Astronomy ,Context (language use) ,Astrophysics ,Energy budget ,Planetary nebula ,Protoplanetary nebula ,Emission nebula ,Astrophysics::Solar and Stellar Astrophysics ,Spectral energy distribution ,Astrophysics::Earth and Planetary Astrophysics ,Astrophysics::Galaxy Astrophysics - Abstract
The past decade has seen significant progress in our understanding of spectral energy distribution of planetary nebulae over the entire wavelength range from UV to radio. In this review we show the detailed breakdown of the energy budget for a planetary nebula as a system of the three components, i.e., the central star, the gaseous nebula and the dust shell. This picture of the energy distribution is further discussed in the context of planetary nebula evolution.
- Published
- 1993
- Full Text
- View/download PDF
193. Reactive oxygen species involved in trichosanthin-induced apoptosis of human choriocarcinoma cells
- Author
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C.-y. ZHANG, Y.-x. GONG, H. MA, C.-c. AN, and D.-y. CHEN
- Subjects
Cell Biology ,Molecular Biology ,Biochemistry - Published
- 2001
- Full Text
- View/download PDF
194. The effect of Si addition in MgB2thin films by hybrid physical–chemical vapor deposition using silane as the doping source
- Author
-
Q. R. Feng, Yinbo Wang, W W Hu, and C Y Zhang
- Subjects
Materials science ,Hybrid physical-chemical vapor deposition ,Doping ,Metals and Alloys ,Analytical chemistry ,Nanotechnology ,Chemical vapor deposition ,Combustion chemical vapor deposition ,Condensed Matter Physics ,Epitaxy ,Silane ,chemistry.chemical_compound ,Carbon film ,chemistry ,Materials Chemistry ,Ceramics and Composites ,Electrical and Electronic Engineering ,Thin film - Abstract
We report the synthesis and characterization of silicon doped MgB2 films fabricated by hybrid physical?chemical vapor deposition using silane as the doping source. Various amounts of Si up to 9% were added into MgB2 thin films, which were epitaxially grown in?situ on SiC. Compared with that of the undoped film, the superconducting transition temperature of the doped film does not show significant change; however the magnetic critical current density (Jc) has been increased. Jc for the film with 5.0?at.% doping goes up to 2.7 ? 105?A?cm ? 2 for a 3?T perpendicular field. And the slope of the upper critical field curve for the doped film is slightly higher than that for the undoped MgB2 film.
- Published
- 2010
- Full Text
- View/download PDF
195. [Studies on polypeptides. IX. Synthesis and antigen specificity of pre-S region fragments of hepatitis B surface antigen]
- Author
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F, Mao, C, Wang, T M, Cheng, M S, Cai, C Y, Zhang, and Q M, Tao
- Subjects
Viral Hepatitis Vaccines ,Epitopes ,Hepatitis B Surface Antigens ,Molecular Sequence Data ,Amino Acid Sequence ,Protein Precursors ,Peptide Fragments - Abstract
Seven peptide fragments of HBsAg Pre-S region have been synthesized by liquid phase and solid phase methods. All peptide fragments were linked to protein carrier by carbodiimide and glutaraldehyde methods. The antigen specificity of the peptide--protein conjugates was assayed by anti-HBsAg polyclonal antibodies and anti--"a" monoclonal antibody. P1 and P5 were found to have higher antigen specificity.
- Published
- 1992
196. [Alteration in resistance of Plasmodium falciparum to chloroquine after cessation of chloroquine medication for twelve years]
- Author
-
D Q, Liu, R J, Liu, D X, Ren, D Q, Gao, C Y, Zhang, C P, Qiu, X Z, Cai, C F, Ling, A H, Liang, and Y, Tang
- Subjects
Time Factors ,Plasmodium falciparum ,Drug Resistance ,Animals ,Chloroquine ,Longitudinal Studies ,In Vitro Techniques ,Malaria, Falciparum - Abstract
In view of the fact the resistance of Plasmodium falciparum to chloroquine occurred extensively in Hainan, a decision was made in 1979 that the use of chloroquine should be quit in the whole province. A longitudinal survey on chloroquine-sensitivity of P. falciparum was carried out during 1981-1991 to observe the variation in resistance of the parasite after the cessation of the chloroquine medication for every 2-3 years. A tendency of progressive decline of resistance was revealed. By using in vitro test, the rate of chloroquine-resistant P. falciparum dropped from 97.9% in 1981 to 60.9% in 1991 (P0.001). The mean dosage of chloroquine for complete inhibition of schizont formation declined from 10.46 pmol/microliters in 1981 to 3.02 pmol/microliters in 1991 (P0.001). The percentage of population requiring larger dosage (6.4 pmol/microliters to completely inhibit schizont formation declined from 83.3% in 1981 to 17.4% in 1991 (P0.001); whereas those requiring small dosage (1.6 pmol/microliters), increased from 4.2% in 1981 to 60.8% in 1991 (P0.001). In in vivo test, the rate of chloroquine-resistant P. falciparum decreased from 84.2% in 1981 to 40% in 1991 (P0.001). The proportion of RII plus RIII cases of the total resistant cases dropped from 59.4% in 1981 to 37.5% in 1991 (0.02P0.01).
- Published
- 1992
197. Projections of SO2, NOx and carbonaceous aerosols emissions in Asia
- Author
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Jiang Kejun, C. Y. Zhang, Peter Rafaj, R. Mathur, Zbigniew Klimont, Shuxiao Wang, A. Chambers, Markus Amann, Janusz Cofala, Jia Xing, Jiming Hao, Wei Wei, Pallav Purohit, and P. Bhandari
- Subjects
Atmospheric Science ,010504 meteorology & atmospheric sciences ,Meteorology ,010501 environmental sciences ,Atmospheric sciences ,01 natural sciences ,Residential sector ,Air pollutants ,Biofuel ,Model application ,Environmental science ,East Asia ,NOx ,0105 earth and related environmental sciences - Abstract
Estimates of Asian emissions of air pollutants and carbonaceous aerosols and their mid-term projections have been changing significantly in the last years. The remote sensing community has shown that increase in NO x in Central East Asia is much stronger than any of the emission inventories or projections indicated so far. A number of studies reviewing older estimates appeared. Here, we review the key contributions and compare them to the most recent results of the GAINS model application for Asia and to the SRES projections used in the IPPC work. The recent projections indicate that the growth of emissions of SO 2 in Asia should slow down significantly towards 2010 or even stabilize at the current level. For NO x , however, further growth is projected although it will be most likely slower that in the last decade, owing to introduction of measures in transport. Emissions of carbonaceous aerosols (black carbon and organic carbon) are expected to decline after 2010, largely due to reduced use of biofuels in residential sector and efficiency improvements. The estimates of these emissions are burdened with significantly larger uncertainties than SO 2 and NO x ; even for the year 2000 the differences in estimates between studies are up to a factor of 2. DOI: 10.1111/j.1600-0889.2009.00428.x
- Published
- 2009
- Full Text
- View/download PDF
198. Correlation between plasma levels of ACTH and cortisol in basal states and during the CRH test in normal subjects and patients with hypothalamo-pituitary disorders
- Author
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H, Bando, C Y, Zhang, Y, Takada, H, Takahashi, R, Yamasaki, and S, Saito
- Subjects
Adult ,Aged, 80 and over ,Male ,Adolescent ,Hydrocortisone ,Corticotropin-Releasing Hormone ,Pituitary Diseases ,Middle Aged ,Adrenocorticotropic Hormone ,Humans ,Female ,Immunoradiometric Assay ,Cushing Syndrome ,Hypothalamic Diseases ,Aged - Abstract
Using a new ACTH-immunoradiometric assay (IRMA), we measured plasma ACTH levels in the basal states and during CRH test in normal subjects and the patients with hypothalamo-pituitary disorders. The basal levels of plasma ACTH in 76 normal young (25-45 yr) and 140 elderly (60-85 yr) subjects were 23.1 +/- 13.6, and 17.5 +/- 11.2 pg/ml, respectively. The plasma ACTH levels were less than detection limit (5 pg/ml) in 3 patients with isolated ACTH deficiency, and less than 10 pg/ml in 6 of 7 patients with hypopituitarism. A significant correlation was observed between the basal levels of plasma ACTH and of cortisol in two age groups, with almost the same regression line, showing no age-related decline in the plasma levels of ACTH and cortisol. In 2 normal subjects and 2 patients with Cushing's disease, synchronized secretions of ACTH and cortisol were observed between 0800h and 1800h. In normal subjects and the patients with pituitary disorders, a significant correlation was observed between the Area Under the Curve's for plasma ACTH and cortisol during the CRH test. The correlation constant was higher in normal subjects, but lower in the patients with acromegaly, non-functioning pituitary tumor, and Cushing's disease in this order, suggesting low sensitivity of the pituitary-adrenal axis in these patients. These results suggest that the ACTH-IRMA kit provide reliable data for clinical investigation, and that the secretions of ACTH and cortisol correlate each other in basal states and during the CRH test in the patients with pituitary disorders as well as in normal subjects.
- Published
- 1991
199. Immunomodulation of human cytomegalovirus infection on interferon system in patients with systemic lupus erythematosus
- Author
-
X, Zhang, H T, Xu, C Y, Zhang, J J, Liu, C M, Liu, X Z, Chen, and R L, Zhou
- Subjects
Adult ,Male ,Interferon-gamma ,Cytomegalovirus Infections ,Humans ,Interferon-alpha ,Lupus Erythematosus, Systemic ,Female - Abstract
On the basis of the research on the relationship between human cytomegalovirus (HCMV) infection and systemic lupus erythematosus (SLE) a study of the effects of HCMV infection on the immunological pathogenesis of SLE was undertaken. Presented in this paper is a brief account of the study. It was found that SLE patients with active HCMV infection had significant higher level of serum interferon-alpha (IFN-alpha) than those without active HCMV infection, but the IFN-alpha induction capacity of peripheral blood mononuclear cells (PBMC) from SLE patients with active HCMV infection was evidently poorer than that from patients without it. There was not any statistically significant difference between the two SLE groups in the IFN-gamma induction capacity of PBMC.
- Published
- 1991
200. [Synthesis and antimicrobial activity of 7-acylamido-3-1, 2, 3-triazol-1-ylmethyl) cephalosporins]
- Author
-
C Y, Zhang, S C, Hu, H S, Zhou, and T H, Duan
- Subjects
Structure-Activity Relationship ,Gram-Negative Bacteria ,Microbial Sensitivity Tests ,Gram-Positive Bacteria ,Cephalosporins - Abstract
In order to develop oral cephalosporin exhibiting broad-spectrum activity, a series of cephalosporin derivatives (VIII1-12) bearing 1, 2, 3-triazolymethyl substituents on the C3 position were synthesized. 7-Phenylacetamido-3-methyl-3-cephem-4-carboxylic acid (I) was employed as starting material and converted to VIII by procedures of esterification and oxidation, bromination, azido-substitution, dipolarcycloaddition, deprotection, cleavage, and condensation. Minimum inhibitory concentration (MIC) values in vitro showed that VIII2-4.9-11 had a wide antibacterial spectrum against Gram positive and Gram negative bacteria and possessed high activities. Further biological evaluation and the study of oral absorption for the six compounds will be performed.
- Published
- 1991
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