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Chinese Chemical Letters 2006年第11期17卷 1511-1514页

作者： Li Gang REN xiang Yang liu yi GU State Key Laboratory of Polymeric Materials Engineering College of Polymer Science and Engineering Sichuan University Chengdu 610065

A novel diamine 4-[（4＇-butoxyphenoxy）carbonyl]phenyl-3＂,5＂-diaminobenzoate （BCDA） was synthesized from 4-butoxyphenol, 4-hydroxybenzoic acid and 3,5-dinitrobenzoic acid through four main intermediates, and a series of polyimides were also synthesized. All the intermediates and the final product were characterized by FTIR and 1H-NMR. The key step in synthesis route is selective hydrolyzation of two ester groups in 4-butoxyphenyl-4＇-acetoxybenzoate, by adjusting the reaction temperature and the concentration of ammonia, shorteding the reaction time. The properties of the novel polyimides, such as the aggregation structures, glass transition temperature, solubility and the pretilt angles, were carded out.

关键词： Synthesis polyimides side chain alignment film.

Ultra-early amplitude decrement after repetitive nerve stimulation supports early neuromuscular junction injury in amyotrophic lateral sclerosis:a prospective cross-sectional study

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Neural Regeneration Research 2022年第3期17卷 655-660页

作者： Jing-Yue Ma xiang-yi liu Shuo Zhang Dong-Sheng Fan Department of Neurology Peking University Third HospitalBeijingChina Beijing Municipal Key Laboratory of Biomarker and Translational Research in Neurodegenerative Diseases BeijingChina

The dying-back hypothesis holds that the damage to neuromuscular junctions and distal axons in amyotrophic lateral sclerosis occurs at the earliest stage of the *** basic studies have confirmed early damage to neuromuscular junctions,but it is difficult to obtain such evidence directly in clinical *** this prospective cross-sectional study,we recruited 22 patients with early amyotrophic lateral sclerosis with disease duration < 12 months and with clinical symptoms limited to the upper *** also recruited 32 healthy *** nerve stimulation was performed,and patients were followed for 12 *** found a significant change in the response to repetitive nerve stimulation in amyotrophic lateral sclerosis patients without spontaneous electromyographic *** that were prone to denervation had an increased decrement response of target muscles after repetitive nerve *** results suggest that changes in response to repetitive nerve stimulation may occur before denervation in amyotrophic lateral sclerosis *** damage to lower motor neurons is more obvious in patients with a higher percentage of repetitive never stimulation-related amplitude *** study was approved by the Institutional Ethics Committee of Peking University Third Hospital(approval No.M2017198) on August 24,2017.

关键词： amplitude decremental response amyotrophic lateral sclerosis dying-back hypothesis motor neuron disease nerve electrophysiology physiopathology prognosis repetitive nerve stimulation

Promising application of a new ulnar nerve compound muscle action potential measurement montage in amyotrophic lateral sclerosis:a prospective cross-sectional study

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Neural Regeneration Research 2023年第4期18卷 908-912页

作者： yi-Xuan Zhang Jing-Yue Ma xiang-yi liu Shuo Zhang Zhou Yu Dong-Sheng Fan Department of Neurology Peking University Third HospitalBeijingChina Beijing Municipal Key Laboratory of Biomarker and Translational Research in Neurodegenerative Diseases BeijingChina Key Laboratory for Neuroscience National Health Commission/Ministry of EducationPeking UniversityBeijingChina

Previous studies have shown that ulnar nerve compound muscle action potential recorded by the conventional“belly-tendon”montage does not accurately and completely reflect the action potential of the ulnar nerve dominating the abductor digiti minimi muscle due to the effects of far-field potentials of intrinsic hand muscles.A new method of ulnar nerve compound muscle action potential measurement was developed in 2020,which adjusts the E2 electrode from the distal tendon of the abductor digitorum to the middle of the back of the proximal *** new method may reduce the influence of the reference electrode and better reflect the actual ulnar nerve compound muscle action *** this prospective cross-sectional study,we included 64 patients with amyotrophic lateral sclerosis and 64 age-and sex-matched controls who underwent conventional and novel ulnar nerve compound muscle action potential measurement between April 2020 and May 2021 in Peking University Third *** compound muscle action potential waveforms recorded by the new montage were unimodal and more uniform than those recorded by traditional *** the controls,no significant difference in the compound muscle action potential waveforms was found between the traditional montage and new montage *** amyotrophic lateral sclerosis patients presenting with abductor digiti minimi spontaneous activity and muscular atrophy,the amplitude of compound muscle action potential-pE2 was significantly lower than that of compound muscle action potential-dE2(P<0.01).Using the new method,damaged axons were more likely to exhibit more severe amplitude decreases than those measured with the traditional method,in particular for patients in early stage amyotrophic lateral *** addition,the decline in compound muscle action potential amplitude measured by the new method was correlated with a decrease in Revised Amyotrophic Lateral Sclerosis Functional Rating Scale *** findings suggest tha

关键词： amyotrophic lateral sclerosis axonal degeneration biomarker compound muscle action potential distal E2 electrode early diagnosis far field potential nerve electrophysiology prognosis evaluation proximal E2 electrode ulnar motor nerve conduction

Clinical features and therapeutic strategies of obstructive azoospermia in patients treated by bilateral inguinal hernia repair in childhood

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Asian Journal of Andrology 2014年第5期16卷 745-748,I0010页

作者： xiang-Feng Chen Hong-xiang Wang yi-Dong liu Kai Sun Li-Xin Zhou yi-Ran Huang Zheng Li Ping Ping Department of Urology Ren Ji Hospital School of Medicine Shanghai Jiao Tong University Shanghai Institute of Andrology Shanghai China

Childhood inguinal herniorrhaphy is one common cause of seminal tract obstruction. Vasovasostomy （VV） can reconstruct seminal deferens and result in appearance of sperm and natural pregnancy in some patients. Secondary epididymal obstruction caused by a relatively long-term vasal obstruction is a common cause of lower patency compared with VV due to vasectomy in adults. From July 2007 to June 2012, a total of 62 patients, with history of childhood inguinal herniorrhaphy and diagnosed as obstructive azoospermia were treated in our center. The overall patency rate and natural pregnancy rate were 56.5% （35/62） and 25.8% （16/62）, respectively. 48.4% （30/62） of the patients underwent bilateral VV in the inguinal region, with a patency rate of 76.7% （23/30） and a natural pregnancy rate of 36.7% （11/30）, respectively. 30.6% （19/62） of the patients underwent bilateral VV and unilateral or bilateral vasoepididymostomies due to ipsilateral epididymal obstruction with the patency and natural pregnancy rate decreasing to 63.2% （12/19） and 26.3% （5/19）. 21.0% （13/62） of the patients merely underwent vasal exploration without reconstruction due to failure to find distal vasal stump, etc. Our study indicate that microsurgical reanastomosis is an effective treatment for some patients with seminal tract obstruction caused by childhood inguinal herniorrhaphy.

关键词： azoospermia inguinal herniorrhaphy microsurgical reanastomosis

Elimination of HBr from CH_3Br by Cu^+ and Au^+:A DFT study

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Chinese Chemical Letters 2008年第7期19卷 881-884页

作者： Tao Hong Li Chuan Ming Wang xiang yi liu Xiao Guang Xie Faculty of Chemistry Southwest Forestry University Kunming 650224 China Department of Biology Honghe University Menzi 661100 China Department of Chemistry Yunnan University Kunming 650091 China

The elimination of HBr from CH3Br by ground state of Cu＋ and Au＋ has been investigated by using DFT methods. A mechanism of one-step HBr elimination leading to CuCH2＋ was identified. For the formation of AuCH2＋, besides the one-step mechanism, another two-step HBr elimination pathway through a C-Br bond insertion intermediate was also found, and this pathway is energetically more favorable than the one-step mechanism. The calculated reaction energy barriers show that the formation of AuCH2＋ is energetically much more favorable than the formation of CuCH2＋. The experimental observations are well explained.

关键词： Copper and gold Alkyl halide HBr elimination

Influence of vibration on the lubrication effect of a splash-lubricated gearbox

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Journal of Zhejiang University-Science A(Applied Physics & Engineering) 2024年第4期25卷 324-339页

作者： yi liu Kailin ZHANG Shuai SHAO Hongxu xiang Zhijian YE State Key Laboratory of Rail Transit Vehicle System Southwest Jiaotong UniversityChengdu 610031China

In this study,we investigate the effect of rail vibrations on the lubrication and efficiency of a splash-lubricated gearbox;specifically,the gearbox of a rail-transit vehicle.A high-fidelity 3D numerical model of the gearbox in a moving reference system is described,as well as computational fluid dynamics(CFD)simulations of the gearbox with different vibration *** effects of rotational speed,oil-immersion depth,and different oil-injection volume rates on lubrication and efficiency are *** propose a method of evaluating the internal lubrication condition of a splash-lubricated gearbox and quantitatively compare the effects of different operating parameters on lubrication and ***,our experiment to verify the feasibility of the simulation method is *** results show that with vibration,the churning loss and oil supply for the bearings are significantly higher than those under static *** addition,among different vibrational directions,lateral vibration has the greatest influence on the lubrication condition and efficiency of the *** the studied railway-vehicle gearbox,the best lubrication condition is achieved at a rotational speed of 1600 r/min and an oil-immersion depth of two times the tooth height(***).Rotational speed is the operating parameter that has the most significant effect on the lubrication and efficiencyofthegearbox.

关键词： Comprehensive lubrication evaluation Churning loss Moving reference system Splash lubrication Vibrational excitation Gearbox

Vanadium(V) Complexes Containing Unsymmetrical N-Heterocyclic Carbene Ligands: Highly Efficient Synthesis and Catalytic Behavior towards Ethylene/Propylene Copolymerization

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Chinese Journal of Polymer Science 2024年第1期42卷 32-41,I0006页

作者： yi-Cong Wang Hui Zhat Pei-yi Cheng Shu Zhang xiang-Wei liu yi-Xian Wu State Key Laboratory of Chemical Resource Engineering Beijing University of Chemical TechnologyBejing 100029China

The highly efficient method has been developed for the synthesis of NHC·VOCl_(3) containing symmetrical or unsymmetrical Nheterocyclic carbene(NHC) ligands by the transmetallation reaction of NHC·AgCl with VOCl_(3).The total isolated yield of VOCl_(3)[1,3-(2,4,6-Me_(3)C_(6)H_(2))_(2)(NCH=)_(2)C:](V4') reached 86% by transmetallation reaction,which is much higher than that(48%) by direct coordination *** methodology has also been used to synthesize the novel vanadium complexes containing unsymmetrical NHC ligands of VOCl_(3)[PhCH_(2)NCH=CHNR)C:](V5',R=2,4,6-Me_(3)C_(6)H_(2);V6',R=2,4-Me_(2)-6-Ph-C_(6)H_(2);V7',R=2,6-^(i)Pr_(2)-C_(6)H_(3)) with high yield,which could not be obtained by direct coordination *** catalytic activity and copolymerization ability would be improved by introducing unsymmetrical NHC ligands due to their less steric bulky *** vanadium complex V5' containing unsymmetrical NHC ligand exhibits higher catalytic activity(3.7×10^(5)g_(copolymer)·mol^(-1) of V·h^(-1)) than that of V4' containing symmetrical NHC ***,the higher propylene incorporation ratio(45.6 mol%) in the copolymers of ethylene with propylene could be obtained by using V5' than that(39.9%) by using V4'.The results would provide a highly efficient strategy for the synthesis of early transition metal complexes containing versitile NHC ligands,affording the catalyst with both high catalytic activity and copolymerization ability for the synthesis of high performance polyolefin elastomers.

关键词： Vanadium complex N-heterocyclic carbene ligand Transmetallation reaction Copolymerization of ethylene with propylene

Relationship Between Short-chain Fatty Acids and Parkinson’s Disease:A Review from Pathology to Clinic

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Neuroscience Bulletin 2024年第4期40卷 500-516页

作者： Wen-xiang Duan Fen Wang Jun-yi liu Chun-Feng liu Department of Neurology and Clinical Research Center of Neurological Disease The Second Affiliated Hospital of Soochow UniversitySuzhou215004China Department of Neurology Dushu Lake Hospital affiliated to Soochow UniversitySuzhou215125China Jiangsu Key Laboratory of Neuropsychiatric Diseases and Institute of Neuroscience Soochow UniversitySuzhou215123China

Parkinson’s disease(PD)is a complicated neurodegenerative disease,characterized by the accumulation ofα-synuclein(α-syn)in Lewy bodies and neurites,and massive loss of midbrain dopamine *** evidence suggests that gut microbiota and microbial metabolites are involved in the development of *** these,short-chain fatty acids(SCFAs),the most abundant microbial metabolites,have been proven to play a key role in brain-gut *** this review,we analyze the role of SCFAs in the pathology of PD from multiple dimensions and summarize the alterations of SCFAs in PD patients as well as their correlation with motor and non-motor *** research should focus on further elucidating the role of SCFAs in neuroinflammation,as well as developing novel strategies employing SCFAs and their derivatives to treat PD.

关键词： Parkinson’s disease Short-chain fatty acids Microbial metabolites Brain-gut-microbiota axis

Effect of slow shot speed on externally solidified crystal,porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy

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China Foundry 2024年第1期21卷 11-19页

作者： Wen-ning liu Wei Zhang Peng-yue Wang yi-xian liu xiang-yi Jiao Ao-xiang Wan Cheng-gang Wang Guo-dong Tong Shou-mei Xiong School of Materials Science and Engineering Tsinghua UniversityBeijing 100084China Key Laboratory for Advanced Materials Processing Technology Tsinghua UniversityBeijing 100084Beijing China FAW Group Co. Ltd.Changchun 130013China China FAW Foundry Co. Ltd.Changchun 130013China

The effect of slow shot speed on externally solidified crystal(ESC),porosity and tensile property in a newly developed high-pressure die-cast Al-Si alloy was investigated by optical microscopy(OM),scanning electron microscopy(SEM)and laboratory computed tomography(CT).Results showed that the newly developed AlSi9MnMoV alloy exhibited improved mechanical properties when compared to the AlSi10MnMg *** AlSi9MnMoV alloy,which was designed with trace multicomponent additions,displays a notable grain refining effect in comparison to the AlSi10MnMg *** elements Ti,Zr,V,Nb,B promote heterogeneous nucleation and reduce the grain size of primaryα-*** a lower slow shot speed,the large ESCs are easier to form and gather,developing into the dendrite net and *** an increase in slow shot speed,the size and number of ESCs and porosities significantly *** addition,the distribution of ESCs is more dispersed and the net-shrinkage *** tensile property is greatly improved by adopting a higher slow shot *** ultimate tensile strength is enhanced from 260.31 MPa to 290.31 MPa(increased by 11.52%),and the elongation is enhanced from 3.72%to 6.34%(increased by 70.52%).

关键词： hypoeutectic Al-Si alloy high pressure die casting porosity externally solidified crystal tensile property

A computational study on the gas phase reaction of Os^+ with N_2O

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Chinese Chemical Letters 2009年第8期20卷 1010-1014页

作者： Tao Hong Li Chuan Ming Wang Shi Wen Yu xiang yi liu Hui Fu Xiao Guang Xie Faculty of Chemistry Southwest Forestry University Kunming 650224 China Department of Biology Honghe University Menzi 661100 PR China Department of Chemistryl Qujing Normal University Qujing 650011 China Department of Chemistry Yunnan University Kunming 650091 China

The reaction of Os^＋（^6D, ^4F） with N20 has been investigated at B3LYP/TZVP and CCSD（T）/6-311＋G^＊ levels of theory. The mechanisms corresponding to O-atom and N-atom transfer reactions have been revealed. It was found that on the sextet reaction surface both the O-atom and N-atom transfer reactions undergo through direct-abstraction mechanism, leading to the formation of OsO^＋ and OsN^＋, whereas on quartet surface the two reactions undergo through O-N bond or N-N bond insertion mechanism. The calculated energetics shows that the reactions on the sextet surface have notable energy barriers, whereas the reactions on quartet surface are barrierless. ？2009 Xiao Guang Xie. Published by Elsevier B.V. on behalf of Chinese Chemical Society. All rights reserved.

关键词： O-Atom transfer N-Atom transfer Abstraction Insertion