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Pretreatment with Rhodiola Rosea Extract Reduces Cognitive Impairment Induced by Intracerebroventricular Streptozotocin in Rats: Implication of Anti-oxidative and Neuroprotective Effects

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Biomedical and Environmental Sciences 2009年第4期22卷 318-326页

作者： peter chung Division of Neuroscience Department of Histology and Embryology Zhongshan School of Medicine Sun Yat-Sen University

Objective To investigate the pretreatment effects of Rhodiola rosea （R. rosea） extract on cognitive dysfunction, oxidative stress in hippocampus and hippocampal neuron injury in a rat model of Alzheimer＇s disease （AD）. Methods Male Sprague-Dawley rats were pretreated with R. rosea extract at doses of 1.5, 3.0, and 6.0 g/kg for 3 weeks, followed by bilateral intracerebroventricular injection with streptozotocin （1.5 mg/kg） on days 1 and 3. Behavioral alterations were monitored after 2 weeks from the lesion using Morris water maze task. Three weeks after the lesion, the rats were sacrificed for measuring the malondialdehyde （MDA）, glutathione reductase （GR） and reduced glutathione （GSH） levels in hippocampus and histopathology of hippocampal neurons. Results The MDA level was significantly increased while the GR and GSH levels were significantly decreased with striking impairments in spatial learning and memory and severe damage to hippocampal neurons in the model rat induced by intracerebroventricular injection of streptozotocin. These abnormalities were significantly improved by pretreatment with R. rosea extract （3.0 g/kg）. Conclusion R. rosea extract can protect rats against cognitive deficits, neuronal injury and oxidative stress induced by intracerebroventricular injection of streptozotocin, and may be used as a potential agent in treatment of neurodegenerative diseases such as AD.

关键词： Rhodiola rosea Oxidative stress Neuroprotective effect Learning and memory Alzheimer's disease Intracerebroventricular streptozotocin

BIOSYNTHESIS AND THERMAL PROPERTIES OF POLY(3-HYDROXYBUTYRATE-co-3-HYDROXYVALERATE)WITH LARGE VARIETY OF HYDROXYVALERATE CONTENTS BY BACILLUS CEREUS

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Chinese Journal of Polymer Science 2007年第4期25卷 341-345页

作者：严群 chung HimYu peter Hoi Fu Yu Key Laboratory of Industrial Biotechnology Ministry of EducationSouthern Yangtze University Department of Applied Biology and Chemical Technology The Hong Kong Polytechnic UniversityHung HomKowloonHong Kong

Biosynthesis and thermal properties of poly（3-hydroxybutyrate-co-3-hydroxyvalerate）（PHBV） with different HV （hydrovalerate） content produced by a Bacillus cereus strain were investigated. A large variety of HV contents （up to about 90 mol%） of PHBV could be produced by this strain. Combined nitrogen sources containing both yeast extract and ammonium sulphate were better for cell growth and polyhydroxyalkanoates （PHA） production than either yeast extract or ammonium sulphate alone. Propionic acid is more favorable for the production of HV content than that of valeric acid. Finally, thermal properties of PHBV produced by this strain are found close to the results of other groups.

关键词： Bacillus cereus Poly(3-hydroxybutyrate-co-3-hydroxyvalerate) Biosynthesis Thermal properties

Tunable electron and phonon properties of folded single-layer molybdenum disulfide

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Nano Research 2018年第3期11卷 1541-1553页

作者： Jie Peng peter W. chung Madan Dubey Raju R. Namburu Department of Mechanical Engineering University of Maryland College Park MD 20742 USA Sensors & Electron Devices Directorate U.S. Army Research Laboratory Adelphi MD 20783 USA Computational & Information Sciences Directorate U.S. Army Research Laboratory Aberdeen Proving Ground MD 21005 USA

A unique feature of transition metal dichalcogenides is their single-layer form, which enables folding. Although folding has been found to significantly affect the photoluminescence spectrum and some in-plane properties, only limited insight has been gained on how to modulate those properties. In this report, we examine the structure of folds of a single sheet of MoS2 and the dependence of the ground-s tate electronic and phonon transport properties on the wrapping length. As the folded structure is effectively a bilayer that terminates in a loop, the wrapping length modulates the relative size of the bilayer region to the closed loop along the edge. A combination of computational methods, including approaches based on variational mechanics, classical potentials, and density functional theory, are employed. Highly accurate calculations of the reference folded structure are first carried out to show that the folded structure is largely insensitive to the wrapping length. The folded structures are subsequently used to estimate the electronic band gap, which is found to vary significantly as a function of the wrapping length, and converges from below to the limit value corresponding to an infinite bilayer. The gap values range from 0.43 to 1.09 eV, with a crossover to an indirect gap, which suggests that the transitions must be lattice-assisted, similar to the transitions in the bilayer and bulk forms. However, the phonons, while affected by the formation of the folded structure, are insensitive to the wrapping length. In fact, the overall thermal transport behavior along the folding axis is unchanged. The possibility of modulating the gap value while keeping the thermal properties unchanged opens up new exciting avenues for further applications of this emerging material.

关键词： molybdenum disulfide folded structure electronic band structure thermal conductivity phonon

Significant Lifetime Enhancement in QLEDs by Reducing Interfacial Charge Accumulation via Fluorine Incorporation in the ZnO Electron Transport Layer

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Nano-Micro Letters 2022年第12期14卷 432-446页

作者： Dong Seob chung Tyler Davidson-Hall Giovanni Cotella Quan Lyu peter Chun Hany Aziz Department of Electrical and Computer Engineering Waterloo Institute for NanotechnologyUniversity of Waterloo200 University Avenue WestWaterlooON N2L 3G1Canada Ipswich Research Centre Huawei Technologies Research&Development(UK)Ltd.Phoenix House(B55)Adastral ParkIpswich IP53REUK Ottawa IC Laboratory Huawei Canada19 Allstate ParkwayMarkhamON L3R 5B4Canada

ZnO nanoparticles are widely used for the electron transport layers(ETLs)of quantum dots light emitting devices(QLEDs).In this work we show that incorporating fluorine(F)into the ZnO ETL results in significant enhancement in device electroluminescence stability,leading to LT50 at 100 cd m^(−2) of 2,370,000 h in red QLED,47X longer than the control devices.X-ray photo-electron spectroscopy,time-of-flight secondary ion mass spectroscopy,photoluminescence and electrical measurements show that the F passivates oxygen vacancies and reduces electron traps in *** photoluminescence versus bias measurements and capacitance-voltage-luminance measurements reveal that the CF4 plasma-treated ETLs lead to increased electron concentration in the QD and the QD/hole transport layer interface,subsequently decreasing hole accumulation,and hence the higher *** findings provide new insights into the critical roles that optimizing charge distribution across the layers play in influencing stability and present a novel and simple approach for extending QLED lifetimes.

关键词： Colloidal quantum dots Quantum dots light emitting device Device stability Zinc oxide nanoparticles Fluorine

Mitochondrial protective and anti-apoptotic effects of Rhodiola crenulata extract on hippocampal neurons in a rat model of Alzheimer's disease

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Neural Regeneration Research 2017年第12期12卷 2025-2034页

作者： Jun-mei Wang Ze-qiang Qu Jin-lang Wu peter chung Yuan-shan Zeng Department of Histology and Embryology Zhongshan School of Medicine Sun Yat-sen University Guangzhou Guangdong Province China Department of Electron Microscope Zhongshan School of Medicine Sun Yat-sen University Guangzhou Guangdong Province China Shanghai Ninth People's Hospital Shanghai liao Tong University School of Medicine Shanghai China Institute of Spinal Cord In)ury Sun Yat-sen University Guangzhou Guangdong Province China Co-innovation Center of Neuroregeneration Nantong University Nantong Jiangsu Province China Guangdong Province Key Laboratory of Brain Function and Disease Zhongshan School of Medicine Sun Yat-sen University Guangzhou Guangdong Province China

In our previous study, we found that the edible alcohol extract of the root of the medicinal plant Rhodiola crenulata（RCE） improved spatial cognition in a rat model of Alzheimer＇s disease. Another study from our laboratory showed that RCE enhanced neural cell proliferation in the dentate gyrus of the hippocampus and prevented damage to hippocampal neurons in a rat model of chronic stress-induced depression. However, the mechanisms underlying the neuroprotective effects of RCE are unclear. In the present study, we investigated the anti-apoptotic effect of RCE and its neuroprotective mechanism of action in a rat model of Alzheimer＇s disease established by intracerebroventricular injection of streptozotocin. The rats were pre-administered RCE at doses of 1.5, 3.0 or 6.0 g/kg for 21 days before model establishment. ATP and cytochrome c oxidase levels were significantly decreased in rats with Alzheimer＇s disease. Furthermore, neuronal injury was obvious in the hippocampus, with the presence of a large number of apoptotic neurons. In comparison, in rats given RCE pretreatment, ATP and cytochrome c oxidase levels were markedly increased, the number of apoptotic neurons was reduced, and mitochondrial injury was mitigated. The 3.0 g/kg dose of RCE had the optimal effect. These findings suggest that pretreatment with RCE prevents mitochondrial dysfunction and protects hippocampal neurons from apoptosis in rats with Alzheimer＇s disease.

关键词： nerve regeneration Alzheimer's disease intracerebroventricular injection streptozotocin neuronal apoptosis neuroprotection cytochrome c oxidase adenosine triphosphate caspase-3 NeuN neural regeneration

Radiofrequency catheter ablation of ventricular tachycardia in a patient with dermatomyositis

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Journal of Geriatric Cardiology 2016年第11期13卷 927-929页

作者： peter Carlo M Nierras Aida P Maranian Ming-Shien Wen chung-Chuan Chou Division of Cardiology Department of Medicine Chang Gung Memorial Hospital Linkou Taiwan China Section of Cardiology Department of Medicine Philippine General Hospital Manila Philippines Section of Cardiology Department of Medicine Southern Philippines Medical Center Davao City Philippines Chang Gung University College of Medicine Taoyuan Taiwan China

A 51-year old male who presented at our hospital for recurrent palpitation for several months was diagnosed dermatomyositis ten years ago and had interstitial lung disease since two years ago. Recently, he was admitte... 详细信息

关键词： Dermatomyositis Radiofrequency ablation Ventricular tachycardia

Bifidobacterium infantis attenuates colitis by regulating T cell subset responses

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World Journal of Gastroenterology 2014年第48期20卷 18316-18329页

作者： Li Zuo Kai-Tao Yuan Li Yu Qing-Hong Meng peter Chee-Keung chung Ding-Hua Yang Department of Immunology Guiyang Medical College Department of Surgery the First AffiliatedHospital of Sun Yat-sen University Department of Paediatrics Guangzhou First Municipal People’s Hospital Department of Hepatobiliary Surgery Nan Fang Hospital Southern Medical University

AIM: to investigate the effect of Bifidobacterium infantis (B. infantis) on the T cell subsets and in attenuating the severity of experimental colitis in mice.

关键词： Bifidobacterium Colitis Cytokines Th17 Regulatory T cells

Association between smoking,pancreatic insulin secretion and insulin resistance in Chinese subjects with or without glucose intolerance

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Chinese Medical Journal 2007年第24期120卷 2233-2237页

作者： KO Gary Tin-Choi TONG peter Chun-Yip SO Wing-Yee COCKRAM Clive S. CHAN Juliana chung-Ngor Hong Kong Institute of Diabetes and Obesity Hong Kong China Department of Medicine and Therapeutics Chinese University of Hong Kong Prince of Wales Hospital Shatin N.T. Hong KongChina

Background There are studies suggesting smoking may increase the risk of type 2 diabetes. Effects of smoking on insulin secretion and insulin resistance （IR） are, however, controversial. Methods This is a cross-sectional study. Since there were very few smokers among Hong Kong Chinese women, only men （n=-1068） were analyzed in this report. Fasting and 2-hour plasma glucose and insulin were measured. Insulinogenic index as well as beta-cell function and IR based on homeostatic model assessment （HOMA） by computer model （HOMA Calculator v2.2） were calculated. Results Of the 1068 men, 147 had newly diagnosed diabetes, 131 newly diagnosed impaired glucose tolerance （IGT） and 790 were non-diabetic normal controls. Smokers had similar fasting and 2-hour insulin levels, insulinogenic index and HOMA derived beta-cell function as compared to non-smokers in the groups with diabetes, IGT or normal oral glucose tolerance test （OGTT）. IR was also similar between smokers, ex-smokers and non-smokers in those with normal OGTT. In men with IGT or diabetes, after adjustment for age and body mass index, smokers were more insulin resistant as compared to non-smokers （IR, IGT： 1.59±1.07 vs 1.03±0.54, P〈0.05; diabetes： 1.96±1.36 vs 1.06±0.45, P〈0.01）. With Logistic regression analysis, comparing smokers and non-smokers, IR was independently associated with smoking （odds ratio （95% C/）, IGT： 2.23 （1.05, 4.71）; diabetes： 3.92 （1.22, 12.58））. None of the other insulin parameters enter into the model among those with normal OGTT or comparing ex-smokers and non-smoker or smokers and ex-smokers. Conclusions In Chinese men, smoking did not show any direct association with insulin levels and pancreatic insulin secretion. Smoking men with IGT or diabetes appeared more insulin resistant than their non-smoking counterparts.

关键词： smoking diabetes mellitus insulin Chinese

NATURAL SUBSTANCE AND ANTI-CANCER

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NATURAL SUBSTANCE AND ANTI-CANCER