222 results on '"X.-Y. Zhao"'
Search Results
152. Clinical profiles of vitiligo in China: an analysis of 3742 patients
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J.-P. Gui, Xiaoguang Zhang, Hua Wang, Jiang-Bo Liu, Min Li, X.-Y. Zhao, Sen Yang, Ya-Gang Zhu, Yunqing Ren, and Wen-Hui Du
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Adult ,Male ,China ,medicine.medical_specialty ,Adolescent ,Alopecia Areata ,Urticaria ,Population ,Vitiligo ,Dermatology ,Arthritis, Rheumatoid ,Epidemiology ,medicine ,Humans ,Age of Onset ,Child ,skin and connective tissue diseases ,education ,Chronic urticaria ,Pigmentation disorder ,Retrospective Studies ,education.field_of_study ,integumentary system ,business.industry ,Ichthyosis ,Middle Aged ,Alopecia areata ,medicine.disease ,Phenotype ,Rheumatoid arthritis ,Disease Progression ,Female ,business - Abstract
Very few articles have aimed to illuminate the clinical profiles of vitiligo in China. We conducted this retrospective survey involving 4118 outpatients with vitiligo in order to identify the differences among various clinical types of vitiligo and their associated disorders. Completed questionnaires (3742) were validated and analysed. Of this large cohort, 1565 (41.8%) individuals presented vitiligo vulgaris, followed by focal, segmental, acrofacial, and universal, in that order. The mean age of vitiligo onset was 18.88 years. More than 60% of the patients were affected before 20 years of age. Patients with segmental vitiligo were affected earlier than those with other types of vitiligo (15.55 years; (P < 0.001). More than 74% of the patients presented with focal vitiligo at onset. After 3-5 years, 99% of active vitiligo was worse and shifted from one clinical type to another. However, there was no transformation between acrofacial vitiligo and segmental vitiligo. Compared with the general population, the patients with vitiligo were more likely to be affected by rheumatoid arthritis (P < 0.01), ichthyosis (P < 0.01), chronic urticaria (P < 0.01), or alopecia areata (P < 0.01).
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- 2005
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153. SCREENING METHOD FOR RESISTANCE TO TIPBURN IN CHINESE CABBAGE
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X. Y. Zhao, Y. J. Yu, and Jianbin Xu
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Horticulture ,Resistance (ecology) ,Screening method ,Biology - Published
- 2004
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154. Study of Local Piezoelectric Properties for Europium Doped Lead Zirconate Titanate Films by Piezoresponse Force Microscope
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C. L. Choy, Jiyan Dai, X. Y. Zhao, J. Wang, and Hlw L. W. Chan
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Piezoelectric coefficient ,Materials science ,Microscope ,Condensed matter physics ,chemistry.chemical_element ,Coercivity ,Condensed Matter Physics ,Lead zirconate titanate ,Piezoelectricity ,Electronic, Optical and Magnetic Materials ,law.invention ,chemistry.chemical_compound ,chemistry ,Control and Systems Engineering ,law ,Electric field ,Materials Chemistry ,Ceramics and Composites ,Electrical and Electronic Engineering ,Europium ,Voltage - Abstract
Using a sol-gel method, rare earth element europium (Eu) doped lead zirconate titanate (Pb0.925Eu0.05(Zr0.52Ti0.48)O3, denoted as PEZT) films were obtained. A novel method was proposed to measure the PEZT film's local piezoelectric properties by piezoresponse force microscope tip utilizing wire bonding through which external electric field was applied. Relative piezoelectric coefficient (“d33”) and the strain behavior (butterfly loop) of the PEZT films described as the function of electric field were obtained by using this method. The oscillation amplitude against the ac voltage curve is linear, revealing a slope of 3.78 × 10− 5 V/V, and the coercive field estimated from the butterfly loop has a mean value of 27.5 kV/cm. The butterfly loops obtained from different places can be used to describe the transfer and attenuation of the domain vibration in PEZT films.
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- 2004
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155. Correlation Investigation of Radio and Optical Variations in a Large Sample of Fermi Blazars
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B. Z. Dai, B. K. Zhang, Longzhou Zhang, and X. Y. Zhao
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Correlation ,Physics ,010308 nuclear & particles physics ,Space and Planetary Science ,0103 physical sciences ,Astronomy and Astrophysics ,Astrophysics ,Blazar ,010303 astronomy & astrophysics ,01 natural sciences ,Fermi Gamma-ray Space Telescope ,Large sample - Published
- 2017
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156. Molecular characterization of a phytoplasma associated with Euonymus bungeanus witches’ broom in China
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Ronghua Yang, Jing Wang, X. Y. Zhao, Y. R. Dong, G. Z. Tian, Y. M. Wei, S. J. Wang, and Z. G. Ren
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0106 biological sciences ,0301 basic medicine ,Ecology ,Phylogenetic tree ,Broom ,Forestry ,Ribosomal RNA ,Biology ,16S ribosomal RNA ,biology.organism_classification ,01 natural sciences ,law.invention ,03 medical and health sciences ,030104 developmental biology ,law ,Phytoplasma ,Botany ,Phyllody ,Restriction fragment length polymorphism ,Polymerase chain reaction ,010606 plant biology & botany - Abstract
Summary Euonymus bungeanus plants exhibiting symptoms of abnormal branches, small leaves and phyllody, which is indicative of E. bungeanus witches’ broom (EbWB) disease, have recently been found in Beijing, China. A phytoplasma from symptomatic E. bungeanus plants was identified by 16S rRNA polymerase chain reaction (PCR) using the phytoplasma-specific universal primer pair R16mF2/R16mR1. Inoculation of healthy E. bungeanus plants by grafting with diseased scions was also performed. The rp and secY genes of the EbWB phytoplasma were cloned and sequenced as was the 16S rRNA gene. Sequence and phylogenetic analyses of 16S rRNA, rp and secY genes indicated that the phytoplasma associated with E. bungeanus belongs to the 16SrV-B, rpV-C and secY-C subgroup, the same subgroup as the jujube witches’ broom (JWB) phytoplasma that is widely distributed among jujube trees in China. Comparative analyses based on virtual restriction fragment length polymorphism (RFLP) showed that the EbWB phytoplasma is more closely related to another 16SrV-B subgroup strain: RPWB (Robinia pseudoacacia witches’ broom). To the best of our knowledge, this is the first report of a witches’ broom phytoplasma in E. bungeanus in China, and the findings add a new cultivated plant species to the already broad natural host range of 16SrV-B subgroup phytoplasmas.
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- 2017
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157. Magnetoelectric effect from the direct coupling of the Lorentz force from a brass ring with transverse piezoelectricity in a lead zirconate titanate (PZT) disk
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Hlw L. W. Chan, Haosu Luo, Lijie Luo, X. Y. Zhao, Siu Wing Or, Di Zhou, and Yanmin Jia
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Materials science ,Condensed matter physics ,Magnetoelectric effect ,General Chemistry ,Lead zirconate titanate ,Piezoelectricity ,Magnetic field ,chemistry.chemical_compound ,Transverse plane ,symbols.namesake ,Nuclear magnetic resonance ,chemistry ,symbols ,General Materials Science ,Direct coupling ,Lorentz force ,Voltage - Abstract
A novel composite of brass ring and PZT disk shows a high dc magnetic field (Hdc) response when using the product effect of the Lorentz force effect from a metal ring in a dc magnetic field applied with ac electrical current, and the piezoelectric effect of piezoelectric material. The output voltage between the two faces of PZT shows a good linear response to the dc magnetic field (
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- 2007
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158. Synthesis and characterization of semi-interpenetrating liquid crystalline polymer networks LCP/PAN
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Qixiang Zhou, X. Y. Zhao, De-shan Liu, and Yi Du
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chemistry.chemical_classification ,Materials science ,Condensation polymer ,Polymers and Plastics ,Liquid crystalline ,Radical polymerization ,Polyacrylonitrile ,General Chemistry ,Polymer ,Surfaces, Coatings and Films ,chemistry.chemical_compound ,chemistry ,Chemical engineering ,Polymer chemistry ,Materials Chemistry ,Thermal stability ,Interpenetrating polymer network ,Fourier transform infrared spectroscopy - Abstract
A new type of interpenetrating polymer network based on a liquid crystalline polymer: a semi-interpenetrating liquid crystalline polymer network comprising the liquid crystalline polymer (LCP) PET/60PHB and crosslinked polyacrylonitrile (PAN)(for short: semi-ILCPN LCP/PAN) was successfully prepared. The compatibility and thermal properties of the semi-ILCPNs with different amounts of the crosslinking agent were investigated by FTIR, SEM, DSC, and TGA.
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- 1998
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159. Glycoengineered factor IX variants with improved pharmacokinetics and subcutaneous efficacy
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Chandra Patel, J. E. Murphy, E. Blasko, Uwe Gritzan, H. Apeler, Derek Sim, Elena Ho, Liang Tang, X.-Y. Zhao, Alan R. Brooks, and R. I. Feldman
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Glycosylation ,Protein Conformation ,Injections, Subcutaneous ,Biological Availability ,Pharmacology ,Protein Engineering ,Hemophilia B ,Factor IX ,Route of administration ,chemistry.chemical_compound ,Subcutaneous injection ,Mice ,Pharmacokinetics ,medicine ,Animals ,Humans ,Mice, Knockout ,Hematology ,Bioavailability ,Mice, Inbred C57BL ,Disease Models, Animal ,HEK293 Cells ,Coagulation ,chemistry ,Mutagenesis, Site-Directed ,Specific activity ,medicine.drug - Abstract
Summary Background The rapid clearance of factor IX (FIX) necessitates frequent intravenous administration to achieve effective prophylaxis for patients with hemophilia B. Subcutaneous administration would be a preferred route of administration but is limited by bioavailability. Objectives To improve the pharmacokinetics (PK) and bioavailability of FIX, a screen was performed to identify positions for the introduction of novel glycosylation sites with maximal effect on PK and maintenance of coagulation activity. Methods Two hundred fifty-one variants, each containing one additional N-linked glycosylation site, were screened in vitro, and the PK profiles of selected variants mapping to spatially distinct regions of FIX were evaluated in mice. Optimal variants were combined, and their PK and efficacy were determined in mice with hemophilia B. Results Variants that mapped to spatially distinct regions of the FIX structure exhibited different degrees of improved PK and enabled selection of optimized sites while minimizing the loss of FIX activity. Combining the most effective N-glycan sites in the same FIX molecule resulted in further improvements in PK. An optimized variant containing three novel N-glycan sites (at amino acids 103, 151, and 228), and the activity enhancing 338A variant had double the specific activity of wild-type FIX, exhibited 4.5-fold reduced clearance and 2.4-fold increased subcutaneous bioavailability, and was efficacious at a fivefold lower mass dose than wild-type FIX after subcutaneous injection in a bleeding model in mice with hemophilia B. Conclusions Glycoengineering was used to significantly improve the subcutaneous PK and efficacy of FIX and may have advantages for subcutaneous dosing.
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- 2013
160. Thermo-mechanical reliability evaluation for microelectronic packaging using C-mode scanning acoustic microscopy
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X. Y. Zhao, C. G. Xu, H. B. Wang, X. H. Guo, L. Yang, Z. Z. Liu, and K. Peng
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Reliability (semiconductor) ,Materials science ,business.industry ,Delamination ,Microelectronics ,Acoustic microscopy ,Test method ,Integrated circuit packaging ,Temperature cycling ,Composite material ,business ,Thermal expansion - Abstract
C-mode Scanning Acoustic Microscopy (C-SAM) is an excellent tool for nondestructive failure analysis and reliability evaluation of microelectronic packaging. During operation and thermal cycling, defects such as cracks, delamination and voids can emerge and grow under thermo-mechanical stresses caused by materials with different coefficients of thermal expansion (CTE) and mechanical properties. According to the MIL-STD-883H Microcircuits Test Method Standard, the thermal cycling test on a set of microelectronic packaging was conducted and the defects propagation of microelectronic packaging was studied experimentally using C-mode Scanning Acoustic Microscopy.
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- 2013
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161. A new anti-slough drilling fluid study and application
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C C Niu, C Xiao, G Li, X Y Zhao, X T Hou, and Y F Meng
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Petroleum engineering ,Borehole ,Drilling ,equipment and supplies ,Well drilling ,Wellbore ,chemistry.chemical_compound ,Calcium carbonate ,chemistry ,Drilling fluid ,otorhinolaryngologic diseases ,medicine ,Oil field ,Swelling ,medicine.symptom ,Geology - Abstract
Currently the BIOCAT drilling fluid system adopted in oil field results in wellbore collapsing frequently, borehole enlargement rate over 100%. In order to settle these problems, the Impermeable anti-collapsing inhibitive Polymer Drilling Fluids System is developed by optimizing the inhibitors with high anti-collapsing inhibitive instead of BIOCAT inhibitor, adding impermeable agent SMT3, sealing materials such as graphite, calcium carbonate, etc. Laboratory experiments results show that the developed drilling fluid system has stronger inhibitive and anti-collapse capacity. The swelling increment decreases by over 10% and recovery rate increases by 60%-70%, also, it can efficiently prolong the borehole wall stable period by over 100%. 24 wells applications with the Impermeable anti-collapsing inhibitive Polymer Drilling Fluids System achieved good results, comparing to adjacent wells with BIOCAT drilling fluid system, wellbore collapsing decreasing significantly and borehole diameter enlargement of unstable hole section in wells decreased from 100% to 10%, well drilling time decreased by 15%, drilling cost decreased by 10%. It shows that the developed Impermeable anti-collapsing inhibitive Polymer Drilling Fluids System KPAM-NH4PAN can provide strong and long-term inhibition, close to oil-based drilling fluid. so it is suggested that it be used in subsequent drilling operations to enhance the wellbore stability in an oilfield.
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- 2016
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162. The effect of hydrophobicity/hydrophilicity balance of three kinds of adjuvants on pridinol mesylate orally disintegrating tablets and its quality assessment
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L. Y. Luo, P. X. Tian, M. Luo, Q. Chen, X. Y. Zhao, and Y. H. Luo
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Pharmacology ,Microcrystalline cellulose ,chemistry.chemical_compound ,Polyvinylpolypyrrolidone ,Chromatography ,chemistry ,Quality assessment ,Pridinol mesylate ,Pharmaceutical Science ,Balance test - Abstract
This study was aimed at investigating the effects of 3 kinds of adjuvants on the disintegrating ability of pridinol mesylate orally disintegrating tablets (PMODT), and evaluating the quality of PMODT. The hydrophobic balance of 3 adjuvants (polyvinylpolypyrrolidone (PVPP), microcrystalline cellulose (MCC) and Povidone K30 (PVPK30)) were detected using the L9(34) orthogonal test to determine their effects on the disintegrating ability of PMODT. The quality of PMODT was tested according to the requirements of the Chinese Pharmacopoeia (2010). Results indicated that the disintegrability of PMODT decreased with the increasing amount of PVPP from 4 to 8%. However, no significant influence on the disintegrability was found when the amount of MCC was increased from 10 to 15%. On the other hand, the disintegrability decreased with the increasing amount of MCC when the amount was 15 to 20%. Furthermore, the disintegrability was slightly affected when the amount of PVP K30 was 1 to 2%, while the disintegrability decreased when the amount of PVPK30 was at the range of 2 to 3%. The ratio of hydrophobic / hydrophilic adjuvants affected the disintegrability, which showed a “V” shape curve. The disintegrating tablets showed best property when the ratio of PVPP+MCC and PVPK30 (hydrophobicity / hydrophilicity) was 9.5. The results of hydrophobic balance test on the three kinds of adjuvants were consistent with the results of orthogonal test. In general, the quality of 3 batches of PMODT met the relevant requirements of the production of orally disintegrating tablets. This will provide new ideas and methods for thescreening and dosage choice of variety of adjuvants in the study of pharmaceutical preparation. Key words: Adjuvants, hydrophobicity, orally disintegrating tablets, orthogonal design, disintegration.
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- 2012
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163. Preparation of carteolol hydrochloride matrix sustained-release pellets and evaluation in vitro/in vivo
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Z. K. Ge, C. C. Tian, H. Zhang, L. Y. Luo, X. Y. Zhao, Y. H. Luo, Q. Chen, Y. J. Zhang, and M. Luo
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Pharmacology ,Chromatography ,Chemistry ,Hydrochloride ,Pellets ,Cmax ,Pharmaceutical Science ,Carteolol Hydrochloride ,Matrix (chemical analysis) ,chemistry.chemical_compound ,Oral administration ,In vivo ,medicine ,Carteolol ,medicine.drug - Abstract
The aim of this study was to prepare carteolol hydrochloride matrix sustained-release pellets, and to compare its performance in vivo with carteolol common tablets. The formula was optimized according to the roundness and the release of pellets with single-factor, and orthogonal test. The carteolol hydrochloride matrix sustained-release pellets were got by extrusion-spheronisaion, while the release rate in vitro was determined by rotate basket method with UV detection. The carteolol hydrochloride sustained release property was studied in New Zealand white rabbits after oral administration. The optimized prescription is composed of carteolol hydrochloride 5.5 g, MCC 6.0 g, SA 26.3 g, EC 21.0 g, CMC-Na 1.2 g. Drug release property in vitro were as follows: the release time is over 12 h, the drug release behaviors follow the first order equation and the process of drug releasing is drug diffusion with frame erosion. The Cmax, Tmax and AUC(0→24) of the pellets were 2.58 ± 0.43 (mg/ml), 4.20 ± 0.87 (h) and 22.19 ± 4.23 (mg/ml h), respectively. The Cmax, Tmax and AUC(0→24) of the tablets were 3.75 ± 0.59 (mg/ml), 1.00 ± 0.72 (h) and 18.70 ± 3.75 (mg/ml h). The carteolol hydrochloride sustained-release pellets have reasonable formulation and simple preparation technology; the pellets acquired perfect sustained-release properties in vitro/in vivo. Key words: Carteolol hydrochloride, sustained-release, pellets, in vitro, in vivo, evaluation
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- 2012
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164. A positive correlation between plant diversity and productivity is indirectly caused by environmental factors driving spatial pattern of vegetation composition in semiarid sandy grassland
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X. Y. Zhao, Y. Q. Li, X. A. Zuo, Y. R. Guo, H. L. Zhao, and J. M. H. Knops
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geography.geographical_feature_category ,Agroforestry ,Ecology ,fungi ,food and beverages ,Vegetation composition ,respiratory system ,Positive correlation ,complex mixtures ,Grassland ,Geography ,Productivity (ecology) ,Common spatial pattern ,human activities ,Plant diversity - Abstract
Although patterns between plant diversity and ecosystem productivity have been much studied, a consistent relationship has not yet emerged. Several different patterns have been observed both naturally and experimentally, likely caused by spatial variability of environmental factors and vegetation composition. In this study, we measured the vegetation cover, plant diversity, productivity, soil properties and site characteristics along an environment gradient of natural sandy grasslands (mobile dune, semi-fixed dune, fixed dune, dry meadow, wet meadow and flood plain grassland) in a semiarid area of Northern China. We used multivariate analysis to examine the relationships between environment factors, vegetation composition, plant diversity and productivity. We found a positive correlation between plant diversity and productivity. Vegetation composition had also a significantly positive correlation with plant diversity and productivity. Environment gradients in relation to soil properties and topography features affected the distribution patterns of species diversity, vegetation composition and productivity. However, environment gradients are a better determiner for vegetation composition and productivity than for species diversity. The analysis from optimization model of structural equation suggests that environmental factors determine vegetation composition, which in turn drives independently both plant diversity and productivity. Thus the positive correlation between plant diversity and productivity is not direct, but indirectly driven by the spatial pattern of vegetation composition determined by environment gradients in soil and topography.
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- 2011
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165. Immunoglobulin G4-associated de novo autoimmune hepatitis after liver transplantation for chronic hepatitis B- and C-related cirrhosis and hepatocellular carcinoma: a case report with literature review
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J.-d. Jia, T.-I. Wang, X.-y. Zhao, and M.I.A. Rakhda
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Liver Cirrhosis ,Male ,Carcinoma, Hepatocellular ,Time Factors ,medicine.medical_treatment ,Hepatitis C virus ,Autoimmune hepatitis ,Liver transplantation ,medicine.disease_cause ,Antiviral Agents ,Polyethylene Glycols ,Hepatitis B, Chronic ,Pegylated interferon ,Recurrence ,parasitic diseases ,Azathioprine ,Ribavirin ,medicine ,Humans ,Hepatitis ,Transplantation ,business.industry ,Coinfection ,Liver Neoplasms ,Interferon-alpha ,Hepatitis C ,Hepatitis B ,Hepatitis C, Chronic ,Middle Aged ,medicine.disease ,Recombinant Proteins ,Liver Transplantation ,Hepatitis, Autoimmune ,Treatment Outcome ,Hepatocellular carcinoma ,Immunoglobulin G ,Immunology ,Prednisone ,Surgery ,Drug Therapy, Combination ,business ,Immunosuppressive Agents ,medicine.drug - Abstract
Immunoglobulin G4 (IgG4)-associated autoimmune hepatitis (AIH) was recognized as a new disease entity; however, IgG4-associated de novo AIH after the liver transplantation had not been reported yet. Herein we have described a 56-year-old man who developed IgG4 de novo AIH as 1 year-post liver transplantation after receiving pegylated interferon alpha-2a and ribavirin therapy for hepatitis C virus recurrence. The histopathologic evidence showed an aggressive lymphoplasmacytic interface hepatitis with centrilobular necrosis (plasma cells > 30%) and IgG4-positive plasma cells (>10 per high power field). Serum IgG (9220 mg/dL) and IgG4 (3289 mg/dL) were also elevated. Improvement of liver function tests (LFTs) by prednisone and azathioprine therapy are manifested as normalized alanine aminotransferase and IgG levels. IgG4 relates to more severe histological activity; however, it is believed to be a good prognostic predictor of a response to prednisone plus azathioprine therapy especially with early diagnosis and timely management.
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- 2011
166. Simultaneous determination of ibuprofen and diphenhydramine HCl in orally disintegrating tablets and its dissolution by reversed-phase high performance liquid chromatography (RP-HPLC)
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H. Zhang, C. C. Tian, X. Y. Zhao, Y. J. Zhang, Y. H. Luo, and Z. K. Ge
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Pharmacology ,Chromatography ,Diphenhydramine hydrochloride ,Correlation coefficient ,Potassium ,Pharmaceutical Science ,chemistry.chemical_element ,Phosphate ,High-performance liquid chromatography ,Acetic acid ,chemistry.chemical_compound ,chemistry ,Triethylamine ,Dissolution - Abstract
Reversed-phase high performance liquid chromatography (RP-HPLC) methods were established for the simultaneous determination of ibuprofen (IBU) and diphenhydramine HCl (DPH) in orally disintegrating tablets (ODTs) and its dissolution in this work. The separation was performed on a Shim-pack VP-ODS C18 (150 × 4.6 mm, 5 µm) column. The mobile phases of determination and dissolution were a mixture of 0.05 mol/L potassium dihydrogen phosphate buffer (containing 0.2% triethylamine and 0.2% glacial acetic acid)-acetonitrile (54:46, v/v) and a mixture of 0.05 mol/L potassium dihydrogen phosphate buffer-acetonitrile-triethylamine (60:40:0.2), respectively. The mobile phase was delivered at a flow rate of 1.0 ml/min, and the detection was carried out at 263 nm under the column temperature of 30°C and the injection volume of 20 µl. The linear ranges of determination were 100 to 1000 µg/ml with the correlation coefficient of 0.9996 for IBU and 7.5 to 120 µg/ml with the correlation coefficient of 0.9998 for DPH. The average recoveries (n = 9) were 98.52% (relative standard deviation (RSD) = 0.22%) for IBU and 99.07% (RSD = 0.87%) for DPH, respectively. The linear ranges of dissolution were 50 to 800 µg/ml with the correlation coefficient of 0.9999 for IBU and 5 to 80 µg/ml with the correlation coefficient of 0.9999 for DPH; the dissolution both exceeded 80% of the labeled at 10 min. The results showed that the proposed methods were simple, sensitive, accurate and specific. To evaluate its potential application value, IBU and DPH in compound ODTs were simultaneously detected using this approach, and satisfied results were obtained. Key words: Ibuprofen, diphenhydramine hydrochloride (HCl), reversed-phase high performance liquid chromatography (RP-HPLC), determination, dissolution.
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- 2011
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167. Pioglitazone induces regression and stabilization of coronary atherosclerotic plaques in patients with impaired glucose tolerance
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H-B, Yang, X-Y, Zhao, J-Y, Zhang, Y-Y, Du, and X-F, Wang
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Male ,Endothelin-1 ,Pioglitazone ,Remission Induction ,Glucose Tolerance Test ,Middle Aged ,Coronary Vessels ,Lipids ,Plaque, Atherosclerotic ,C-Reactive Protein ,Treatment Outcome ,Humans ,Hypoglycemic Agents ,Female ,Thiazolidinediones ,Adiponectin ,Prospective Studies ,Ultrasonography, Interventional - Abstract
To observe the effects of pioglitazone on coronary plaque area, plaque burden, serum high-sensitivity C-reactive protein, adiponectin and plasma endothelin-1 levels in patients with impaired glucose tolerance and coronary borderline lesions.Thirty patients were randomly divided into two groups: a pioglitazone group and a control group. The latter was administered placebo in addition to standard therapy; the former pioglitazone 15 mg/d in addition to standard therapy. Before treatment and 6 months later, left ventricular ejection fraction, serum lipid profile, high-sensitivity C-reactive protein, adiponectin and plasma endothelin-1 levels were detected. Coronary plaque area and plaque burden were examined using intravascular ultrasound.No significant differences were found in left ventricular ejection fraction and serum lipid levels pre- and post-trial. Compared with the control group, 6 months' treatment with pioglitazone significantly decreased coronary plaque burden (50.7 ± 11.1 vs. 64.1 ± 10.3%, P0.05), plaque area (6.22 ± 2.03 vs. 8.31 ± 4.29, P0.05), thin-cap fibroatheroma prevalence (11 vs. 22%, P0.05) and percentage of necrotic core area (16 ± 8 vs. 31 ± 7%, P0.05). Compared with the control group, serum high-sensitivity C-reactive protein and plasma endothelin-1 levels were significantly lower and adiponectin level significantly higher in patients in the pioglitazone group. Serum adiponectin level was negatively correlated with plasma endothelin-1 level and coronary plaque area (r = 0.739 and -0.431, respectively, both P0.05).Pioglitazone may induce regression and stabilization of coronary atherosclerotic plaques. The mechanisms might involve inhibition of inflammation, increase in adiponectin level and improvement in endothelial function.
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- 2011
168. Negative autoregulation of the neu gene is mediated by a novel enhancer
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X Y Zhao and Mien Chie Hung
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Regulation of gene expression ,Start codon ,Transcription (biology) ,Cell Biology ,Biology ,Enhancer ,Molecular Biology ,Gene ,Transcription factor ,Psychological repression ,DNA-binding protein ,Molecular biology - Abstract
In an attempt to study potential feedback regulation of the neu oncogene, we have found that the neu oncogene product specifically represses its own promoter activity. Deletion analysis indicated a 140-bp region (nucleotides -312 to -173 relative to the ATG initiation codon) in the rat neu promoter responsible for neu autorepression. Gel shift assays and methylation interference analysis further demonstrated that a GGTGGGGGGG sequence (nucleotides -243 to -234 relative to the ATG initiation codon) in this 140-bp region interacts with specific protein complexes. The GGTGGGGGGG sequence (GTG element), which functions as an enhancer, is sufficient to cause neu-mediated repression in a heterologous promoter. Furthermore, it produces different gel shift patterns with nuclear extracts from neu-transformed cell lines and their parental lines, suggesting that a transcriptional factor(s) interacting with this enhancer element has been perturbed by the introduction of neu. Taken together, the data presented in this report show that (i) the neu oncogene product autorepresses its own promoter, (ii) the neu promoter contains a novel enhancer, and (iii) neu autorepression is mediated through this enhancer, likely by inhibition of the enhancer activity.
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- 1992
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169. Modal Parameters Identification of Concrete Structure Based on Built-in PZT Sensors
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X. Y. Zhao and H. N. Li
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Frequency response ,Computer science ,business.industry ,Acoustics ,Passive monitoring ,Structural engineering ,Smart material ,Lead zirconate titanate ,Piezoelectricity ,Vibration ,chemistry.chemical_compound ,Modal ,chemistry ,Structural health monitoring ,business - Abstract
Structural modal parameters identification so far has been a major issue in health monitoring system, for which damage diagnosis methods are based on. The emergence and development of smart materials have provided the more accurate techniques in structural parameters measurement. Piezoceramic material has the advantages of cheap, wide band frequency response and high sensitivity to strain variation. In this paper, PZT sensors encapsulated by cement were firstly made and the dynamic performance test proceeded on the MTS. Embedded into concrete pillar, the sensors can identify the vibration parameters of structure based on the direct piezoelectric effect. Impact test result shows that the PZT sensors signal can correctly render the regular pattern of the damped natural vibration of structure. So the modal parameters can be identified by the PZT sensors signal. Introduction Piezoelectric ceramic materials, such as Lead Zirconate Titanate (PZT), with functions of both sensing and actuating have become one of the potential smart materials for use in structural health monitoring and control of civil structures. Structural health monitoring and damage detection based on piezoelectric ceramic material has become one of the most important research topics since PZT has distinct advantages, such as quick response, broadband frequency and low price, among others, over traditional sensor materials. The piezoelectric-based health monitoring methods can be classified into two major groups: the passive sensing methods and the active sensing methods. According to the character of the PZT material, the former method mostly focuses on the monitoring of impact loads using the direct piezoelectric effect. The latter again can be sorted into three aspects, namely, the impedance-based method, the vibration-characteristic-based method and the Lamb-wave-based method (Song et al., 2004) in which monitoring is carried out by analyzing the variation of the high-frequency elastic waves generating by the PZT sensor. Although the two modes health monitoring methods based on PZT are respectively with its own advantage, the former could response the structure deformation without active excitation source which is more adaptable for monitoring structure in dynamic pattern especially for structure in a natural disaster. Furthermore, for civil structures of low natural frequency, passive monitoring method can save the
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- 2008
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170. Antigenic and immunogenic characterization of infectious bronchitis virus strains isolated in China between 1986 and 1995
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Z Q Wu, Q W Yang, X Y Zhao, C Fu, and Jagoda Ignjatovic
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Serotype ,General Immunology and Microbiology ,Strain (chemistry) ,medicine.drug_class ,A serotype ,Infectious bronchitis virus ,Biology ,medicine.disease ,Monoclonal antibody ,Virology ,Article ,Microbiology ,Food Animals ,Antigen ,medicine ,Animal Science and Zoology ,Flock ,Nephritis - Abstract
Eight strains of infectious bronchitis virus (IBV) were isolated between 1986 and 1995 from broilers and layers at eight different farms in four provinces in China. The viruses were isolated from flocks which suffered from either respiratory disease or nephritis and the majority had not been vaccinated against IBV. Six strains were shown by monoclonal antibodies to differ from H120, Connecticut and Arkansas 99 strains of IBV and also to differ from each other. Four of these strains were serotyped; one (NRZ) was of the Massachusetts serotype, three (HV, NB-90 and TJ) shared a degree of antigenic similarity and were of a serotype that differed from Massachusetts and Connecticut. NB-90 was similar to both Gray and T strains whereas TJ shared some similarity with the T strain. Four strains, HV, NB-90, YY and TJ induced 33, 47, 60 and 90% mortality, respectively, in 3-week-old specific pathogen-free chickens. Clinical signs and post-mortem findings were identical to those induced by the nephropathogenic T strain. Chickens vaccinated with H120 strain, and then challenged with four highly pathogenic strains HV, NB-90, YY and TJ were not protected as determined by both virus isolation and mortality. The results show that highly pathogenic IBV strains which induce clinical nephritis occur frequently in poultry flocks in China. They also confirm field observations on the lack of protection by currently used IB vaccines of the Massachusetts serotype against challenge with these nephropathogenic strains.
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- 2008
171. Resveratrol protects against arsenic trioxide-induced cardiotoxicity in vitro and in vivo
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X-Y, Zhao, G-Y, Li, Y, Liu, L-M, Chai, J-X, Chen, Y, Zhang, Z-M, Du, Y-J, Lu, and B-F, Yang
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Male ,Cytoplasm ,Mice, Inbred BALB C ,Heart Diseases ,L-Lactate Dehydrogenase ,Caspase 3 ,Cell Survival ,Oxides ,In Vitro Techniques ,Antineoplastic Agents, Phytogenic ,Research Papers ,Arsenicals ,Electrocardiography ,Mice ,Oxidative Stress ,Arsenic Trioxide ,Microscopy, Fluorescence ,Resveratrol ,Stilbenes ,In Situ Nick-End Labeling ,Animals ,Calcium ,Female ,Myocytes, Cardiac ,Reactive Oxygen Species - Abstract
The clinical use of arsenic trioxide (As(2)O(3)), a potent antineoplastic agent, is limited by its severe cardiotoxic effects. QT interval prolongation and apoptosis have been implicated in the cardiotoxicity of As(2)O(3). The present study was designed to evaluate the effects of resveratrol on As(2)O(3)-induced apoptosis and cardiac injury.In a mouse model of As(2)O(3)-induced cardiomyopathy in vivo, QT intervals and plasma enzyme activities were measured; cardiac tissues were examined histologically and apoptosis assessed. In H9c2 cardiomyocyte cells, viability, apoptosis, generation of reactive oxygen species (ROS) and cellular calcium levels were measured.In the mouse model, resveratrol reduced As(2)O(3)-induced QT interval prolongation and cardiomyocyte injury (apoptosis, myofibrillar loss and vacuolization). In addition, increased lactate dehydrogenase activity and decreased activities of glutathione peroxidase, catalase and superoxide dismutase were observed in the plasma of As(2)O(3)-treated mice; these changes were prevented by pretreatment with resveratrol. In As(2)O(3)-treated H9c2 cardiomyocytes, resveratrol significantly increased cardiomyocyte viability and attenuated cell apoptosis as measured by acridine orange/ethidium bromide staining, TdT-mediated dUTP nick end labelling assay and caspase-3 activity. As(2)O(3)-induced generation of ROS and intracellular calcium mobilization in H9c2 cells was also suppressed by pretreatment with resveratrol.Our results showed that resveratrol significantly attenuated As(2)O(3)-induced QT prolongation, structural abnormalities and oxidative damage in the heart. In H9c2 cardiomyocytes, resveratrol also decreased apoptosis, production of ROS and intracellular calcium mobilization induced by treatment with As(2)O(3). These observations suggested that resveratrol has the potential to protect against cardiotoxicity in As(2)O(3)-exposed patients.
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- 2008
172. A novel missense mutation L468Q of keratin 6a in pachyonychia congenita type 1
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Min Gao, Yan-Hua Liang, S. Yang, Yunqing Ren, W. G. Li, Xiaoguang Zhang, H.L. Zhou, X.-Y. Zhao, Wen-Hui Du, and Ya-Gang Zhu
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Genetics ,China ,Genodermatosis ,Keratin-6 ,Mutation, Missense ,Dermatology ,Keratin 6A ,Gene mutation ,Biology ,medicine.disease ,Molecular biology ,Polymerase Chain Reaction ,Infectious Diseases ,Palmoplantar keratoderma ,Pachyonychia Congenita ,medicine ,Pachyonychia congenita ,Missense mutation ,Humans ,Female ,Keratoderma ,Child ,Nested polymerase chain reaction - Abstract
Background Pachyonychia congenita is an autosomal dominant disorder that usually develops in early infancy. The major features of the syndrome are hypertrophic nail dystrophy, palmoplantar keratoderma and oral leucokeratosis, accompanied by other ectodermal defects, according to subtype. Objective To analyse the K6a gene mutation in a sporadic Chinese patient with pachyonychia congenita type 1 (PC-1) and to explore the relationship between the genotype and phenotype of PC-1. Methods Genomic DNA was extracted from peripheral blood of the patient with PC-1 and 100 unrelated controls. The whole coding region of K6a gene was amplified using long-range polymerase chain reaction (PCR); nested PCR was then used to amplify the mutation ‘hot-spot’ of the K6a gene. The PCR products were directly sequenced to detect the mutation. Results A novel missense mutation L468Q in the helix 2B domain of the K6a polypeptide was identified in the patient but not in the healthy individuals from the family and 100 unrelated control individuals. Conclusions We describe this mutation for the first time, and provide further evidence that the helix boundary motif sequences of K6a are a mutation ‘hot-spot’.
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- 2007
173. Two novel TSC2 mutations in Chinese patients with tuberous sclerosis complex and a literature review of 20 patients reported in China
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X Y, Zhao, S, Yang, H L, Zhou, Y G, Zhu, L, Wei, W H, Du, Y Q, Ren, Y H, Liang, Y X, Hou, J J, Chen, and X J, Zhang
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Adult ,Male ,Base Sequence ,Tumor Suppressor Proteins ,DNA Mutational Analysis ,Molecular Sequence Data ,Middle Aged ,Pedigree ,Asian People ,Tuberous Sclerosis ,Mutation ,Tuberous Sclerosis Complex 2 Protein ,Humans ,Female ,Aged - Published
- 2006
174. RELATIONS BETWEEN CHILDREN AND MATERNAL NUTRIMENT IN QINGHAI AND GANSU, NORTHWESTERN RURAL CHINA.
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J., ZHANG, H., KANG, L. F., WANG, X. Y., ZHAO, R. P., LIU, and L., HE
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MATERNAL nutrition ,CHILD nutrition ,MIDDLE-income countries ,DISEASE prevalence ,ANTHROPOMETRY - Abstract
Background and Objectives: We know that in low- and middle-income countries maternal and children's under nutriment is responsible for the advancement in deaths and other diseases. A study was designed here to establish a relationship between maternal and children's nutriment in northwestern rural China. Methods: We conducted this prevalence analysis between October 2016 to December 2016 in northwestern rural China by choosing 2021 mothers of children (5 months < age ≤ 24 months) as study subjects. We used standard and calibrated methods and techniques to measure the weight and height of mothers and horizontal lengths of children. Results: We calculated the Z-scores of 'weight for height' (WfH), 'weight for age' (WfA) and 'height for age' (HfA) and found the values less than -2 for 8.2%, 10.5% and 12.6% children, respectively. We found association between nutriment of children and maternal anthropometrical features and also between maternal characteristics and Z-scores of HfA (P = 0.012) and WfH (P = 0.042) of children was also achieved. Conclusion: Maternal good nutriment and good salary is found to be beneficial for children's nutriment. Thus for the betterment of mother and child's health, maternal nutriment as well as her guaranteed financial empowerment should be improved. [ABSTRACT FROM AUTHOR]
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- 2017
175. [Studies on chemical constituents of Fragaria ananassa Duch]
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J I, Ruan, J B, Chen, X Y, Zhao, N J, Sun, J M, Cassady, and G D, Stoner
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Plants, Medicinal ,Fruit ,Phytosterols ,Fragaria ,Sitosterols ,Triterpenes - Abstract
To study the chemical constituents from the fruit of Fragaria ananassa.Using chromatographic methods to isolate compounds and chemical and spectral methods to elucidate their structures.Three compounds, 9, 19-cyclolanost-24-en-3-ol(1), 14-methyl-stigmasta-7, 24(28)-dien-3-ol(2) and beta-sitosterol(3) were isolated from the freeze-dried powder.All of the compounds were obtained from this plant for the first time.
- Published
- 2003
176. [The effect of heat shock before rat partial hepatectomy on HSC70/HSP68 expression and phosphatase activities]
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C S, Xu, A L, Lu, M, Xia, X Y, Li, Y H, Li, and X Y, Zhao
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Male ,Rats, Sprague-Dawley ,Acid Phosphatase ,HSC70 Heat-Shock Proteins ,Animals ,Hepatectomy ,Female ,HSP70 Heat-Shock Proteins ,Alkaline Phosphatase ,Heat-Shock Response ,Liver Regeneration ,Rats ,Signal Transduction - Abstract
The contribution and content of the continuous heat shock protein 70/induced heat shock protein 68 (HSC70/HSP68), the contribution, variety and activity of acid phosphatases (ACP) and alkaline phosphatases (AKP) had been analysed qualitatively and quantitatively during the liver regeneration after 2/3 hepatectomy (PH) and HS (heat shock at 46 degrees C for 30 min, recovery for 8 h), which were compared with the results only by HS and only by PH. It was shown that the three kinds of treatment all can increase the activity of ACP, AKP and the expression of HSC70/HSP68, but with different change pattern. A further analysis show that after HS-PH the enhanced activity of ACP is related with that of 140 kD phosphatases, the enhanced activity of AKP is associated with that of 140 kD and 160-180 kD phosphatases. It can be reckoned from the results that ACP, AKP and HSC70/HSP68 all act on the heat shock response of hepatocyte and liver regeneration, and may take part in signal transduction in these processes, but ACP may play a dominant role in the start of hepatocyte multiplication, AKP and HSC70/HSP68 may play a dominant role in cytokineses.
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- 2003
177. [Cardiovascular effects of lateral intracerebroventricular injection of L-securinine]
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X Y, Zhao, Z Y, Jiang, and J Z, Peng
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Male ,Sympathetic Nervous System ,Blood Pressure ,Azepines ,Kidney ,Heterocyclic Compounds, 4 or More Rings ,Heterocyclic Compounds, Bridged-Ring ,Rats ,Electrophysiology ,GABA Antagonists ,Rats, Sprague-Dawley ,Lactones ,Alkaloids ,Piperidines ,Heart Rate ,Animals ,Injections, Intraventricular - Abstract
To investigate cardiovascular effects of changed GABAergic tonic activation in periventricular forebrain, arterial pressure (AP), heart rate (HR) and renal sympathetic nerve discharge (RSND) were recorded in anesthetized rats when L-securinine (L-Sec) was administered into the lateral intracerebroventricle. L-Sec elicited dose-dependent increases in RSND, AP and HR, which were much weaker than those of bicuculline. L-Sec antagonized the sympatho-inhibitory and depressor effects evoked by both muscimol and baclofen. These results indicate that GABAergic inhibition originating from periventricular forebrain may suppress tonically sympathetic outflow to cardiovascular system which is disinhibited by L-Sec, and L-Sec is likely an unselective GABA receptor antagonist.
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- 2002
178. First Report of Citrus yellow vein clearing virus on Lemon in Yunnan, China
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Yan Zhou, Kezhi Tang, Zhongan Li, Xuefeng Wang, Chen Hongming, X. Y. Zhao, J. Q. Yue, and Cheng-He Zhou
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Tangor ,biology ,food and beverages ,Plant Science ,Orange (colour) ,Herbaceous plant ,biology.organism_classification ,Horticulture ,Ponkan ,Virus morphology ,Plant virus ,Botany ,Sesamum ,Solanum ,Agronomy and Crop Science - Abstract
Eureka lemon (Citrus limon) is an economically important crop in China. In 2009, a new disease was observed on Eureka lemon in an orchard of Ruili city in Yunnan Province. Nearly 10% of the plants were symptomatic with yellow vein clearing on lateral veins, combined with leaf crinkling and warping of young leaves. Water-soaked appearances were also seen on the adaxial leaf veins. The symptoms were present on mature leaves, resulting in almost 20% yield reduction. The symptoms on leaves were more severe in spring and autumn than in summer. This disease was transmitted by grafting from infected Eureka lemon to six lemon (C. limon) varieties (Femminello, Fino, Villafranca, Verna, Kutdiken, and Monachello) and two sour orange (C. aurantium) varieties (Daidai, Morocco), with inoculated plants showing similar symptoms. Variable symptoms were observed on other hosts, including severe yellowing and vein clearing on Dweet tangor (C. reticulata × C. sinensis), slight vein clearing on Tongshui 72-1 sweet orange (C. sinensis) and Marsh grapefruit (C. paradisi), but no symptoms were observed on Etrog citron (C. medica), Mexican lime (C. aurantifolia), or Ponkan (C. reticulata). When infected branches from Etrog citron, Mexican lime, and Ponkan were grafted onto healthy Morocco sour orange, typical yellowing and vein clearing symptoms were observed. In the mechanical transmission trials using eight herbaceous plant species, leaf rolling, shrinking, and pointed necrosis were observed on Vigna unguiculata, slight leaf rolling symptoms were observed on Capsicum frutescens, whereas Lycopersicum esculenum, Nicotiana benthamiana, Momordica charantia, Solanum melongena, Cucumis sativus, and Sesamum indicum remained symptomless. Symptom expression was influenced by temperature, being visible between 18 and 24°C but disappearing over 32°C. Crude extracts from young symptomatic lemon leaves were negatively stained for transmission electron microscopy observation (1) and showed filamentous virus particles of 13 to 15 × 400 to 1,000 nm. The described combination of symptoms in citrus species and herbaceous indicators, and virus morphology revealed by electron microscopy, suggested presence of Citrus yellow vein clearing virus (CYVCV). RNA extractions were made from 52 samples of Eureka lemon with yellow vein clearing symptoms. A one-step RT-PCR using primer pair (sense: 5′-TACCGCAGCTATCCATTTCC-3′ and antisense: 5′-GCAGAAATCCCGAACCACTA-3′), designed from coat protein gene of CYVCV genome (GenBank Accession No. JX040635) (1), was performed. All of the symptomatic samples yielded the expected cDNA fragment and no amplicon was obtained from healthy plants. Three PCR amplicons were selected for cloning and sequencing. BLAST analysis showed that these nucleotide sequences (KJ859679 to 81) had greater than 97% nucleotide identity with the corresponding region of CYVCV reference genome (2), and therefore, this disease was associated with CYVCV. Symptoms resembling CYVCV infection were observed in China before (3); however, to our knowledge, this is the first proven report of CYVCV present in China. The identification of the pathogen now allows for appropriate field management and control measures. References: (1) V. Grimaldi et al. 13th IOCV Conference, 343-345, 1996. (2) G. Loconsole et al. Phytopathology 102:1168, 2012. (3) C. Zhou et al. 18th IOCV Conference, 44, 2010.
- Published
- 2014
- Full Text
- View/download PDF
179. [Changes in the content and activity of HSC70/HSP68, proteinases and phosphatases during liver regeneration]
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C S, Xu, M, Xia, A L, Lu, X Y, Li, Y H, Li, X Y, Zhao, and Y H, Hu
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Male ,Rats, Sprague-Dawley ,Random Allocation ,Acid Phosphatase ,Endopeptidases ,Animals ,Female ,HSP70 Heat-Shock Proteins ,Alkaline Phosphatase ,Liver Regeneration ,Rats - Abstract
This article reports changes in acid and alkaline phosphatases (ACP and AKP), constitutive heat shock protein 70/induced heat shock protein 68 (HSC70/HSP68) and acid and neutral proteinases during liver regeneration (0-144 h) after 2/3 hepatectomy (partial hepatectomy, PH). Both ACP and AKP had two active peaks at 4 and 48 h, 16 and 96 h, respectively, which were followed by significant decrease. The content of HSC70/HSP68 also showed two peaks (16 and 96 h), of which the content after the second peak decreased more obviously than after the first peak. Moreover a 90 kD neutral proteinase was induced at the time from 2 to 6 h and a 27 kD acid proteinase was induced at 36 h. The results suggest that the ACP and the 90 kD neutral proteinase may participate in activating hepatocytes from G0-phase into G1-phase, and AKP and HSC70/HSP68 may play a role mainly in DNA synthesis, cellular metabolism and proliferation. Furthermore 27 kD acid proteinase may be involved in re-differentiation of hepatocytes and reconstruction of liver tissue.
- Published
- 2001
180. Insulin-like growth factor binding protein-3 mediates 1 alpha,25-dihydroxyvitamin d(3) growth inhibition in the LNCaP prostate cancer cell line through p21/WAF1
- Author
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B J, Boyle, X Y, Zhao, P, Cohen, and D, Feldman
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Male ,Calcium Channel Agonists ,Insulin-Like Growth Factor Binding Protein 3 ,Calcitriol ,Tumor Cells, Cultured ,Humans ,Prostatic Neoplasms ,Enzyme-Linked Immunosorbent Assay ,Oligonucleotides, Antisense ,Up-Regulation - Abstract
We determined that insulin-like growth factor binding protein 3 (IGFBP-3) induction by 1,25-dihydroxyvitamin D(3) (1,25-(OH)(2)D(3)) is a necessary component of 1,25-(OH)(2)D(3) mediated growth inhibition of the LNCaP human prostate cancer cell line. In addition, induction of the cyclin dependent kinase inhibitory protein p21/WAF/CIP1 by 1,25-(OH)(2)D(3) is mediated by IGFBP-3.Induction of IGFBP-3 by 1,25-(OH)(2)D(3) was determined by enzyme-linked immunosorbent assay for IGFBP-3 protein and by Northern blot analysis for IGFBP-3 messenger (m) RNA. Growth assays for LNCaP cells were determined by measuring DNA content. The contribution of IGFBP-3 toward 1,25-(OH)(2)D(3) mediated growth inhibition was determined by adding either antisense oligonucleotides or immuno-neutralizing antibodies to culture media of growth assays. Regulation of p21/WAF/CIP1 was determined by Western blot analysis.Adding 1,25-(OH)(2)D(3) to LNCaP prostate cancer cells demonstrated that 1,25-(OH)(2)D(3) significantly up-regulated IGFBP-3 at the mRNA and protein levels in these cells approximately 3-fold over control levels. Also, adding IGFBP-3 protein to LNCaP cell growth medium inhibited LNCaP cell growth. Interestingly adding IGFBP-3 antisense oligonucleotides or antibodies directed toward IGFBP-3 abolished the growth inhibitory actions of 1,25-(OH)(2)D(3), indicating that this effect is IGFBP-3 dependent. Furthermore, to connect the mechanisms of IGFBP-3 and 1,25-(OH)(2)D(3) mediated growth inhibition we demonstrated that IGFBP-3 up-regulates the expression of p21/WAF1 protein to approximately 2-fold over the control level. Adding an IGFBP-3 immuno-neutralizing antibody completely prevented the 1,25-(OH)(2)D(3) induced up-regulation of p21/WAF1.1,25-(OH)(2)D(3) up-regulates IGFBP-3 in the LNCaP cell line at the mRNA and protein levels. The growth inhibitory action of 1,25-(OH)(2)D(3) on LNCaP cells depends on active IGFBP-3, as evidenced by the loss of growth inhibition induced by IGFBP-3 antisense oligonucleotide and immuno-neutralization experiments. A possible connection between IGFBP-3 and 1,25-(OH)(2)D(3) lies in the cyclin dependent kinase inhibitory protein p21/WAF1 since IGFBP-3 and 1,25-(OH)(2)D(3) each up-regulate this protein and both inhibit LNCaP cell growth. Therefore, we hypothesize that the mechanism of action by which IGFBP-3 and 1,25-(OH)(2)D(3) induce growth inhibition is the induction of p21/WAF1 because IGFPB-3 immuno-neutralizing antibodies completely abrogate the 1,25-(OH)(2)D(3) mediated up-regulation of p21/WAF1 and growth inhibition.
- Published
- 2001
181. [Cloning of a full length cDNA of human thrombopoietin receptor c-Mpl and construction of engineered cells that stably express c-mpl]
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X Y, Zhao, J L, Cai, W L, Dai, W G, Zhou, C B, Li, and S Y, Zhao
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DNA, Complementary ,Reverse Transcriptase Polymerase Chain Reaction ,Proto-Oncogene Proteins ,Humans ,Cloning, Molecular ,Receptors, Cytokine ,K562 Cells ,Transfection ,Receptors, Thrombopoietin ,Neoplasm Proteins - Abstract
A full length cDNA fragment encoding for human thrombopoietin receptor c-Mpl has been amplified by RT-PCR from the total RNA of human HEL cells. The complete sequence of the cloned cDNA was determined and is identical to that previously reported. Then the fragment was subcloned into the mammalian expression vector pcDNA3 and the resulting plasmid is designated as pcMPL. K562 cells, which do not express c-mpl, were transfected with pcMPL and pcDNA3, respectively. The transformants were selected with G418 and then tested by Northern and Southern blotting. A group of engineered cell lines stably expressing c-mpl have been obtained, which will facilitate further research on the signaling mediated by c-Mpl.
- Published
- 2000
182. Liarozole acts synergistically with 1alpha,25-dihydroxyvitamin D3 to inhibit growth of DU 145 human prostate cancer cells by blocking 24-hydroxylase activity
- Author
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L H, Ly, X Y, Zhao, L, Holloway, and D, Feldman
- Subjects
25-Hydroxyvitamin D3 1-alpha-Hydroxylase ,Male ,Calcitriol ,Imidazoles ,Tumor Cells, Cultured ,Humans ,Prostatic Neoplasms ,Receptors, Calcitriol ,Drug Synergism ,Enzyme Inhibitors ,Cell Division ,Half-Life - Abstract
1Alpha,25-dihydroxyvitamin D3 [1,25-(OH)2D3] inhibits the proliferation of many cancer cells in culture, but not the aggressive human prostate cancer cell line DU 145. We postulated that the 1,25-(OH)2D3-resistant phenotype in DU 145 cells might result from the high levels of expression of 25-hydroxyvitamin D-24-hydroxylase (24-hydroxylase) induced by treatment with 1,25-(OH)2D3. As this P450 enzyme initiates 1,25-(OH)2D3 catabolism, we presumed that a high level of enzyme induction could limit the effectiveness of the 1,25-(OH)2D3 antiproliferative action. To examine this hypothesis we explored combination therapy with liarozole fumarate (R85,246), an imidazole derivative currently in trials for prostate cancer therapy. As imidizole derivatives are known to inhibit P450 enzymes, we postulated that this drug would inhibit 24-hydroxylase activity, increasing the 1,25-(OH)2D3 half-life, thereby enhancing 1,25-(OH)2D3 antiproliferative effects on DU 145 cells. Cell growth was assessed by measurement of viable cells using the MTS assay. When used alone, neither 1,25-(OH)2D3 (1-10 nM) nor liarozole (1-10 microM) inhibited DU 145 cell growth. However, when added together, 1,25-(OH)2D3 (10 nM)/liarozole (1 microM) inhibited growth 65% after 4 days of culture. We used a TLC method to assess 24-hydroxylase activity and demonstrated that liarozole (1-100 microM) inhibited this P450 enzyme in a dose-dependent manner. Moreover, liarozole treatment caused a significant increase in 1,25-(OH)2D3 half-life from 11 to 31 h. In addition, 1,25-(OH)2D3 can cause homologous up-regulation of the vitamin D receptor (VDR), and in the presence of liarozole, this effect was amplified, thus enhancing 1,25-(OH)2D3 activity. Western blot analyses demonstrated that DU 145 cells treated with 1,25-(OH)2D3/liarozole showed greater VDR up-regulation than cells treated with either drug alone. In summary, our data demonstrate that liarozole augments the ability of 1,25-(OH)2D3 to inhibit DU 145 cell growth. The mechanism appears to be due to inhibition of 24-hydroxylase activity, leading to increased 1,25-(OH)2D3 half-life and augmentation of homologous up-regulation of VDR. We raise the possibility that combination therapy using 1,25-(OH)2D3 and liarozole or other inhibitors of 24-hydroxylase, both in nontoxic doses, might serve as an effective treatment for prostate cancer.
- Published
- 1999
183. Induction of androgen receptor by 1alpha,25-dihydroxyvitamin D3 and 9-cis retinoic acid in LNCaP human prostate cancer cells
- Author
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X Y, Zhao, L H, Ly, D M, Peehl, and D, Feldman
- Subjects
Gene Expression Regulation, Neoplastic ,Male ,Protein Synthesis Inhibitors ,Calcitriol ,Receptors, Androgen ,Tumor Cells, Cultured ,Humans ,Prostatic Neoplasms ,Tretinoin ,Cycloheximide ,Alitretinoin ,Cell Division ,Up-Regulation - Abstract
We have recently shown that 1alpha,25-dihydroxyvitamin D3 [1,25-(OH)2D3] inhibits proliferation of LNCaP cells, an androgen-responsive human prostate cancer cell line. Also, 1,25-(OH)2D3 increases androgen receptor (AR) abundance and enhances cellular responses to androgen in these cells. In the current study, we have investigated the mechanism by which 1,25-(OH)2D3 regulates AR gene expression and the involvement of AR in the 1,25-(OH)2D3- and 9-cis retinoic acid (RA)-mediated growth inhibition of LNCaP cells. Northern blot analyses demonstrated that the steady-state messenger RNA (mRNA) level of AR was significantly increased by 1,25-(OH)2D3 in a dose-dependent manner. Time-course experiments revealed that the increase of AR mRNA by 1,25-(OH)2D3 exhibited delayed kinetics. In response to 1,25-(OH)2D3, AR mRNA levels were first detected to rise at 8 h and reached a maximal induction of 10-fold over the untreated control at 48 h; the effect was sustained at 72 h. Furthermore, the induction of AR mRNA by 1,25-(OH)2D3 was completely abolished by incubation of cells with cycloheximide, a protein synthesis inhibitor. 1,25-(OH)2D3 was unable to induce expression of an AR promoter-luciferase reporter. Together, these findings indicate that the stimulatory effect of 1,25-(OH)2D3 on AR gene expression is indirect. Western blot analyses showed an increase of AR protein in 1,25-(OH)2D3-treated cells. This increased expression of AR was followed by 1,25-(OH)2D3-induced inhibition of growth in LNCaP cells. Similar to 1,25-(OH)2D3, 9-cis RA also induced AR mRNA expression, and the effect of both hormones was additive. Moreover, 1,25-(OH)2D3 and 9-cis RA acted synergistically to inhibit LNCaP cell growth. These antiproliferative effects of 1,25-(OH)2D3 and 9-cis RA, alone or in combination, were blocked by the pure AR antagonist, Casodex. In conclusion, our results demonstrate that growth inhibition of LNCaP cells by 1,25-(OH)2D3 and 9-cis RA is mediated by an AR-dependent mechanism and preceded by the induction of AR gene expression. This finding, that differentiating agents such as vitamin D and A derivatives are potent inducers of AR, may have clinical implications in the treatment of prostate cancer.
- Published
- 1999
184. Auditory P300, CT scans and cognitive state in Binswanger's disease
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C F, Chen, H Y, Jia, X Y, Zhao, H, Guo, W, Luo, and X, Cao
- Subjects
Male ,Cognition ,Dementia, Vascular ,Evoked Potentials, Auditory ,Brain ,Humans ,Female ,Middle Aged ,Tomography, X-Ray Computed ,Event-Related Potentials, P300 ,Aged - Abstract
The P300 component of evoked potential can reflect cognitive state in dementia patients. The purpose of this study was to investigate the value of P300 as an indicator of cognition in Binswanger's disease (BD) and to explore the possible causes of dementia in BD patients. P300 was measured at Cz site in 21 patients with BD and 21 controls matched with age, sex, handedness, and education. This measurement included P300 latency and amplitude. All patients were also given WAIS-RC test and scanned with computerized tomography (CT), and were treated with hyperbaric oxygenation (HBO). The relationships among P300, CT and WAIS-RC score were studied. BD patients had significantly prolonged P300 latency and a tendency of low amplitude P300, but the amplitude difference was not significant compared with controls. P300 latency was found to be negatively correlated with WARS-RC scale, and positively correlated with the change of white matter low attenuation (WMLA). WMLA was also correlated with WAIS-RC score. Treatment with HBO reduced P300 latency and had effect on the cognitive part of P300 but had no effect on CT changes. The significant association between neurophysiological and neuropsychological measurement suggests that P300 measurement reflects a disrupted aspect of cognitive function in BD patients, and it may be a useful means to assess the degree of subcortical cognitive deterioration and the effect of therapy. White matter lesion in BD is concerned to the occurrence of dementia by disturbing axonal conduction.
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- 1997
185. Effects of quercetin on production and release of endothelin and cGMP from cultured endothelial cells
- Author
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X Y, Zhao and Z L, Gu
- Subjects
Umbilical Veins ,Endothelins ,Humans ,Quercetin ,Endothelium, Vascular ,Cyclic GMP ,Cells, Cultured - Abstract
To evaluate the effects of quercetin (Que) on the formation and release of endothelin (ET) and cyclic guanosine monophosphate (cGMP) by endothelial cells.Radioimmunoassay (RIA) was used to assess the amounts of ET and cGMP produced by unstimulated human umbilical vein cells (HUVEC) or HUVEC stimulated with activated platelets and thrombin.Following the treatment of the cultured HUVEC with activated platelets, the amount of ET in the medium was increased, but no significant effect on cGMP within the cells was seen. Thrombin not only increased the amount of ET in the medium, but also raised the level of cGMP within the cells. Pretreatment of HUVEC with Que 0.5, 5, and 50 mumol.L-1, the release of ET by HUVEC stimulated with thrombin and thrombin-activated platelets was much inhibited. Que 0.5-50 mumol.L-1 markedly increased the amount of cGMP in HUVEC stimulated with thrombin and activated platelets. Que also inhibited the release of ET from unstimulated HUVEC, but increased the production of cGMP from unstimulated EC.Thrombin and activated platelets stimulated the release of ET from HUVEC and Que inhibited the release of ET and promoted the formation of cGMP from HUVEC.
- Published
- 1996
186. Cyclic mechanical fatigue of a feldspathic dental porcelain
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S N, White, X Y, Zhao, Y, Zhaokun, and Z C, Li
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Dental Stress Analysis ,Analysis of Variance ,Potassium Compounds ,Materials Testing ,Regression Analysis ,Aluminum Silicates ,Stress, Mechanical ,Models, Theoretical ,Dental Porcelain ,Elasticity - Abstract
A blunt-indentation fracture mechanics technique was used to investigate the response of a feldspathic dental porcelain to cyclic mechanical fatigue. The indentation stress-strain curve was determined first, which showed the critical pressure necessary for crack initiation. This research also demonstrated that pressures too small to cause immediate catastrophic failure can still cause irreversible damage. A second series of fatigue experiments, using pressure parameters chosen from the first project investigated strength loss. These experiments showed that the porcelain was susceptible to cyclic mechanical fatigue, and that cyclic mechanical fatigue is different from quasistatic fatigue. Strength loss curves indicated that cyclic mechanical fatigue damage is cumulative and permitted quantification of the severity of accumulated damage.
- Published
- 1995
187. [Current progress in the treatment of acute promyelocytic leukemia with retinoic acid]
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H, Zeng and X Y, Zhao
- Subjects
Leukemia, Promyelocytic, Acute ,Recurrence ,Drug Resistance ,Humans ,Tretinoin - Published
- 1994
188. [Clinical analysis of ovarian and cervical malignant lymphoma]
- Author
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W F, Wang, R, Sun, and X Y, Zhao
- Subjects
Adult ,Ovarian Neoplasms ,L-Lactate Dehydrogenase ,Lymphoma, Non-Hodgkin ,Humans ,Uterine Cervical Neoplasms ,Female ,Middle Aged ,Prognosis ,Combined Modality Therapy ,Aged ,Retrospective Studies - Abstract
From Oct. 1980 to Oct. 1990, 456 cases with ovarian malignant tumor and 1,281 cases with cervical malignant tumor were admitted in our hospital. Among them, 7 were ovarian lymphoma and 3 were cervical lymphoma, accounting for 1.5% and 0.23% of ovarian and cervical malignant tumors respectively. According to the standard set up by Foxs, 5 were primary and 5 were metastatic in 10 lymphoma cases. Ovarian and cervical lymphoma were few, the primary cases were fewer. But its prognosis was better than the metastatic cases. The prognosis varied with the stages, the more advanced clinical stage, the high worse prognosis. The following condition indicates poor prognosis: rapid onset of abdominal symptoms; the presence of systemic symptoms; bone marrow infiltration; bilateral ovarian tumors; noncleaved cell pattern and cleaved-noncleaved cell mixture pattern; only treated with chemotherapy. Surgery was the first choice in the treatment of lymphoma. The typical operation on ovarian lymphoma was total hysterectomy, bilateral adnexectomy and omentectomy. The cytoreductive surgery which was used to advanced ovarian cancer was also proper for lymphoma, leaving the remained tumor 2cm in diameter, followed by introperitoneal and intravenous chemotherapy. The chemotherapy method was COP or COHP regimen. The treatment of primary cervical lymphoma was radical hysterectomy and pelvic paraaorta abdominal lymphodenectomy or radiotherapy. It seems that lymphoma was highly sensitive to radiotherapy. But radiotherapy was not proper for the metastatic cases because the affected areas were large. SLDH elevated in 5 cases of the 6 cases. It suggested that SLDH can serve as relative indicator for the diagnosis and prognosis of lymphoma.
- Published
- 1994
189. Proposed Mechanisms for the Involvement of Lactoferrin in the Hydrolysis of Nucleic Acids
- Author
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X Y Zhao and T W Hutchens
- Subjects
Nuclease ,biology ,Lactoferrin ,Chemistry ,food and beverages ,RNA ,chemistry.chemical_compound ,Hydrolysis ,Biochemistry ,Agarose gel electrophoresis ,biology.protein ,Nucleic acid ,Ribonuclease ,DNA - Abstract
Lactoferrin has recently been proposed to have ribonuclease activity in the absence of bound iron. We and others have demonstrated previously that lactoferrin interacts with DNA and will bind a number of transition metal ions via surface-exposed histidyl residues. In the present study, we investigated the possibility that surface-bound copper ions on lactoferrin may catalyze the production of active oxygen species responsible for the hydrolysis of nucleic acids. Purified lactoferrin (apo- and holo-forms) was incubated with CuCl2 in solution to obtain lactoferrin with surface binding sites saturated by Cu(II) ions. The lactoferrin-Cu(II) complex was purified by Bio-Gel P-6 chromatography columns and tested for hydrolytic activity against DNA and RNA as analyzed by agarose gel electrophoresis. Incubation of lactoferrin-Cu(II) complexes with supercoiled plasmid Bluescript II SK DNA led to the rapid formation of relaxed open circular or linear forms of DNA characterized by changed electrophoretic mobility. Lactoferrin with bound Cu(II) also caused extensive degradation of yeast tRNA molecules in the presence of hydrogen peroxide. Covalent modification of surface-exposed histidyl residues by carboxyethylation with diethylpyrocarbonate abolished the lactoferrin-associated hydrolytic activity. These results indicate that lactoferrin-bound Cu(II) can indeed facilitate the hydrolysis of DNA and RNA molecules. Copper-binding sites on lactoferrin appear to serve as centers for repeated production of hydroxyl radicals via a Fenton-type Haber-Weiss reaction. Enhanced nuclease activity associated with elevated local concentrations of lactoferrin would promote microbial degradation.
- Published
- 1994
- Full Text
- View/download PDF
190. Proposed mechanisms for the involvement of lactoferrin in the hydrolysis of nucleic acids
- Author
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X Y, Zhao and T W, Hutchens
- Subjects
Lactoferrin ,Deoxyribonucleases ,Ribonucleases ,Spectrophotometry ,Hydrolysis ,Humans ,RNA ,DNA ,Apoproteins ,Chromatography, Affinity ,Plasmids - Abstract
Lactoferrin has recently been proposed to have ribonuclease activity in the absence of bound iron. We and others have demonstrated previously that lactoferrin interacts with DNA and will bind a number of transition metal ions via surface-exposed histidyl residues. In the present study, we investigated the possibility that surface-bound copper ions on lactoferrin may catalyze the production of active oxygen species responsible for the hydrolysis of nucleic acids. Purified lactoferrin (apo- and holo-forms) was incubated with CuCl2 in solution to obtain lactoferrin with surface binding sites saturated by Cu(II)ions. the lactoferrin-Cu(II) complex was purified by Bio-Gel P-6 chromatography columns and tested for hydrolytic activity against DNA and RNA as analyzed by agarose gel electrophoresis. Incubation of lactoferrin-Cu(II) complexes with supercoiled plasmid Bluescript II SK DNA led to the rapid formation of relaxed open circular or linear forms of DNA characterized by changed electrophoretic mobility. Lactoferrin with bound Cu(II) also caused extensive degradation of yeast tRNA molecules in the presence of hydrogen peroxide. Covalent modification of surface-exposed histidyl residues by carboxyethylation with diethylpyrocarbonate abolished the lactoferrin-associated hydrolytic activity. These results indicate that lactoferrin-bound Cu(II) can indeed facilitate the hydrolysis of DNA and RNA molecules. Copper-binding sites on lactoferrin appear to serve as centers for repeated production of hydroxyl radicals via a Fenton-type Haber-Weiss reaction. Enhanced nuclease activity associated with elevated local concentrations of lactoferrin would promote microbial degradation.
- Published
- 1994
191. The Occurrence of Satsuma Dwarf Virus in China
- Author
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X. Y. Zhao, Y. H. Jiang, X. H. He, and C. Y. Zhou
- Subjects
Horticulture ,Satsuma dwarf virus ,biology ,Life Sciences ,biology.organism_classification ,China - Published
- 1993
192. [The polymerization shrinkage of light cure composite resin]
- Author
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X Y, Zhao
- Subjects
Dental Materials ,Time Factors ,Chemical Phenomena ,Light ,Chemistry, Physical ,Materials Testing ,Color ,Composite Resins - Abstract
The polymerization shrinkage of a number of commercially available composite resin (Starfiil, Durafill, VLC-1 and GD) and an experimental composite #1 which contains 16% DMSOC (a new monomer which expands on polymerization) has been determined using a water-filled dialometer. The results indicated that GD displayed the largest shrinkage value at 2.62 +/- 0.20%, while VLC-1, Durafill and Staifill had smaller values at 2.10 +/- 0.10%, 1.84 +/- 0.20% and 1.42 +/- 0.16%, respectively. The experimental composite. #1 underwent least contraction during setting (0.14 +/- 0.13%). The polymerization shrinkage was influenced by the filler loading and the duration of the exposure to the activating light source. There was little influence of shade of materials on the polymerization shrinkage for VLC-1.
- Published
- 1991
193. [Diagnosis of pancreatic cancer with simultaneous detection of a pancreatic-cancer-associated antigen and pancreas-specific antigen]
- Author
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X Y, Zhao, S Y, Yu, and L, Bai
- Subjects
Pancreatic Neoplasms ,Antigens, Neoplasm ,Biomarkers, Tumor ,Humans ,Enzyme-Linked Immunosorbent Assay - Abstract
We reported the purification and characterization of a pancreatic cancer-associated antigen from normal colonic mucosa (PCAAc) and pancreas-specific antigen (PaA) according to Kitada's and Loor's methods as well as the established method of double antibody enzyme-linked immunoassay for the detection of serum PaA and PCAAc; respectively. In our study, 155 serum samples were detected (including normal controls 40; pancreatic cancer 31; other malignant disease 56 and benign diseases 28). The results indicated that the overall sensitivity and specificity of a single PCAAc test for pancreatic cancer were calculated to be 70.98% and 96.43%; a single PaA to be 80.65% and 95.23%, respectively. Furthermore, the sensitivity and specificity of combined tests (PCAAc and/or PaA) for pancreatic cancer were calculated to be 96.77% and 90.91%. The diagnostic efficiency was 90.91%. None of 84 cases of nonpancreatic cancer and benign diseases has been found elevated PCAAc and PaA simultaneously. The results suggest that simultaneous detection of PCAAc and PaA would have increased the sensitivity of diagnosis for pancreatic cancer.
- Published
- 1990
194. [The relationship between IL-2 production and T cell subpopulation in patients with systemic lupus erythematosus]
- Author
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D P, Zuo, Q S, Tian, and X Y, Zhao
- Subjects
Adult ,CD4-Positive T-Lymphocytes ,Male ,T-Lymphocyte Subsets ,Humans ,Interleukin-2 ,Lupus Erythematosus, Systemic ,Female - Abstract
The authors reported IL-2 production and T cell subpopulation of peripheral blood lymphocytes from patients with systemic lupus erythematosus(SLE). The results indicated that patients with SLE showed a decreased IL-2 production and a decreased T4/T8 cell ratio. The relation between IL-2 production and T4/T8 ratio was also observed. Our data suggest that IL-2 production correlates significantly with T4/T8 cell ratio.
- Published
- 1990
195. [Histological changes of the thymus in the aged]
- Author
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X Y, Zhao and T L, Wang
- Subjects
Adult ,Aged, 80 and over ,Male ,Aging ,Cerebrovascular Disorders ,Liver Neoplasms ,Myocardial Infarction ,Humans ,Female ,Thymus Gland ,Middle Aged ,Aged ,Syphilis, Cardiovascular - Abstract
Thymus tissues from 70 autopsy cases (aged 40-89 years) were examined. The thymic parenchyma decreased progressively corresponding with ageing and was replaced synchronously by the adipose tissue. Anyhow, the thymic tissue did not disappear completely, but became small irregular islands distributed dispersively in the fibroadipose tissue and lost its normal structure of thymic lobules and demarcation between cortex and medulla. Additionally, lymphocytes and Hassall's corpuscles were markedly decreased in number. In stress involution caused by chronic diseases, the thymic parenchyma presented further atrophic changes.
- Published
- 1990
196. Influence of fullerene dispersion on high temperature thermoelectric properties of BayCo4Sb12-based composites
- Author
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L. D. Chen, S. Q. Bai, Xun Shi, Q. Yao, X. Y. Zhao, X. Y. Huang, and Ctirad Uher
- Subjects
Fullerene ,Materials science ,General Physics and Astronomy ,chemistry.chemical_element ,Spark plasma sintering ,Sintering ,Barium ,engineering.material ,Condensed Matter::Materials Science ,chemistry ,Impurity ,Condensed Matter::Superconductivity ,Thermoelectric effect ,engineering ,Condensed Matter::Strongly Correlated Electrons ,Grain boundary ,Skutterudite ,Composite material - Abstract
BayCo4Sb12-based composites with dispersed fullerene or barium fulleride have been synthesized by the solid state reaction and spark plasma sintering technique. When fullerene was used as a dispersed phase, a part of barium in the filled skutterudite reacted with fullerene to form barium fullerides. Most of the extended impurity aggregated to form large defects at the grain boundaries of the matrix. The thermoelectric properties of the composites were measured from room temperature to 850 K. Both the electrical conductivity and thermal conductivity decreased with increasing impurity contents. We attributed these significant reductions to enhanced grain-boundary scattering of charge carriers and phonons. A large ZT value of 1.3 was obtained in a composite with an appropriate content of fullerene dispersants.
- Published
- 2007
- Full Text
- View/download PDF
197. Room-temperature ferromagnetism in n-type Cu-doped ZnO thin films
- Author
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H. J. Zhou, X. L. Li, X. Y. Zhao, X. J. Ye, Congmian Zhen, H. J. Meng, and D. L. Hou
- Subjects
Magnetization ,Nuclear magnetic resonance ,Materials science ,Ferromagnetic material properties ,Ferromagnetism ,Sputtering ,Transition temperature ,Analytical chemistry ,General Physics and Astronomy ,Curie temperature ,Thin film ,Sputter deposition - Abstract
A series of n-type Cu-doped ZnO thin films was prepared by magnetron sputtering. Such films have shown ferromagnetic properties at room temperature. The Cu ion is in a univalent state as identified by x-ray photoelectron spectroscopy. The moment per Cu ion decreases as the Cu concentration increases. The largest moment about 0.52 μB∕Cu was observed for Zn0.95Cu0.05O thin film. The Curie temperature about 360 K was observed for Zn0.95Cu0.05O:N film. To explore the relationship between ferromagnetism and carrier density, nitrogen was introduced into the samples which resulted magnetization and the transition temperature decreasing. These results indicate that the electron density plays an important role in ferromagnetism.
- Published
- 2007
- Full Text
- View/download PDF
198. Synthesis and thermoelectric properties of KyCo4Sb12
- Author
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Sai Bai, Zhi-Gang Mei, X. Y. Zhao, Yanzhong Pei, Xun Shi, Xinxing Li, Wei Zhang, and Lidong Chen
- Subjects
Thermal conductivity ,Materials science ,Physics and Astronomy (miscellaneous) ,Condensed matter physics ,Electrical resistivity and conductivity ,Seebeck coefficient ,Atom ,Thermoelectric effect ,Figure of merit ,Crystallite ,Thermoelectric materials - Abstract
Polycrystalline K-filled CoSb3 are synthesized successfully. The uplimit for K filling is at least 0.45, being higher than those of either alkaline-earth (AE) or rare-earth (RE) metals but being in consistent with our earlier theoretical prediction. The measured transport properties (300–800K) show that K filling does not lower thermal conductivity much in comparison with AE or RE filling due to the relatively low mass of K atom. However, it improves electrical conductivity, retains large Seebeck coefficient, and leads to a reasonably good thermoelectric performance for the filled skutterudites. The maximum figure of merit ZT reaches 1 at 800K for K0.38Co4Sb12.
- Published
- 2006
- Full Text
- View/download PDF
199. Synthesis of YbyCo4Sb12∕Yb2O3 composites and their thermoelectric properties
- Author
-
Lidong Chen, Xinxing Li, Wenfu Zhang, Yanzhong Pei, Xun Shi, Sai Bai, X. Y. Zhao, and Takashi Goto
- Subjects
chemistry.chemical_compound ,Thermal conductivity ,Materials science ,Physics and Astronomy (miscellaneous) ,Phonon scattering ,chemistry ,Phonon ,Thermoelectric effect ,Oxide ,Figure of merit ,Grain boundary ,Composite material ,Nanoscopic scale - Abstract
Composites containing Yb-filled CoSb3 and well-distributed Yb2O3 particles are synthesized by in situ reaction method. The structural, chemical, and transport properties of the composites are studied. Some Yb2O3 particles with microsize locate at the grain boundaries of matrix and others distribute within YbyCo4Sb12 grains as nanoscale inclusions. The combination of the “rattling” of Yb ions inside the voids of CoSb3 and the phonon scattering of the oxide defects results in a remarkable reduction in the lattice thermal conductivity. The thermoelectric performance of the composites is significantly improved, and the maximum figures of merit reach 1.3 for the Yb0.25Co4Sb12∕Yb2O3 and 1.2 for the Yb0.21Co4Sb12∕Yb2O3 composites at 850K.
- Published
- 2006
- Full Text
- View/download PDF
200. Study of domain boundary polarization in (111)-cut [Pb(Mg1∕3Nb2∕3)O3]0.7(PbTiO3)0.3 single crystal by piezoresponse force microscopy
- Author
-
X. Y. Zhao, Jiyan Dai, K. S. Wong, H. S. Luo, X. Z. Zhao, and Chung-loong Choy
- Subjects
Condensed Matter::Materials Science ,Crystallography ,Materials science ,Piezoresponse force microscopy ,Physics and Astronomy (miscellaneous) ,Condensed matter physics ,Capacitive sensing ,Orthorhombic crystal system ,Ising model ,Polarization (waves) ,Single crystal ,Ferroelectricity ,Piezoelectricity - Abstract
Ferroelectric domain structure, especially the domain boundary polarization, in as-grown and poled (111)-cut PMN-30%PT single crystal has been studied by means of out-of-plane and in-plane piezoresponse force microscopies (PFMs). It revealed that the as-grown sample exhibits speckle-shaped microdomains, and the domain number distribution decreases exponentially as the domain size increases which can be described by the random field Ising model; in contrast, the poled sample shows stripe-shaped domains. Capacitive force-free PFM revealed a detailed domain boundary characteristic with net in-plane polarization. The presence of the in-plane polarization at the domain boundary also suggests the existence of orthorhombic phase in the rhombohedral matrix.
- Published
- 2006
- Full Text
- View/download PDF
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