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A Modified Molecular Structural Mechanics Method for Analysis of Carbon Nanotubes

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Chinese Journal of Chemical Physics 2006年第4期19卷 286-290页

作者： Ming-yuan huang Hai-bo Chen Ji-nan Lü Pin Lü Pei-qiang Zhang CAS Key Laboratory of Mechanical Behavior and Design of Materials Department of Modern MechanicsUniversity of Science and Technology of China Hefei 230027 China

A modified molecular structural mechanics method, based on molecular mechanics and similar to the finite element method, was developed. The energy of a system was expressed by the force field functions of the molecular mechanics. Under the small deformation assumption and by the principle of minimum potential energy, the system function was established. The properties of tension and bending of single-walled carbon nanotubes were analyzed. The Young＇s modulus is about 0.36 TPa nm, which agrees perfectly with the results of previous analysis by other researchers. It is found, for the first time, that the Young＇s moduli, for Zigzag nanotubes, are different from each other when the system energy was expressed as the sum of two or three individual energy terms in molecular mechanics. Whereas, the Young＇s moduli were the same for the Armchair nanotubes. It is found, when simulating the bending, that the deflections are closer to the theoretical ones, of the classical elasticity, when the diameter of the carbon nanotube increases.

关键词： Carbon nanotube Molecular mechanics Molecular structural mechanics method

An Overview of Mineral Dust Modeling over East Asia

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Journal of Meteorological Research 2017年第4期31卷 633-653页

作者： Siyu CHEN Jianping huang Yun QIAN Chun ZHAO Litai KANG Ben YANG Yong WANG Yuzhi LIU Tiangang yuan Tianhe WANG Xiaojun MA Guolong ZHANG Key Laboratory for Semi-Arid Climate Change of the Ministry of Education Lanzhou University Atmospheric Science and Global Change Division Pacific Northwest National Laboratory School of Atmospheric Sciences Nanjing University Department of Earth System Science Tsinghua University

East Asian dust（EAD） exerts considerable impacts on the energy balance and climate/climate change of the earth system through its influence on solar and terrestrial radiation, cloud properties, and precipitation efficiency. Providing an accurate description of the life cycle and climate effects of EAD is therefore critical to better understanding of climate change and socioeconomic development in East Asia and even worldwide. Dust modeling has undergone substantial development since the late 1990 s, associated with improved understanding of the role of EAD in the earth system. Here, we review the achievements and progress made in recent decades in terms of dust modeling research,including dust emissions, long-range transport, radiative forcing（RF）, and climate effects of dust particles over East Asia. Numerous efforts in dust/EAD modeling have been directed towards furnishing more sophisticated physical and chemical processes into the models on higher spatial resolutions. Meanwhile, more systematic observations and more advanced retrieval methods for instruments that address EAD related science issues have made it possible to evaluate model results and quantify the role of EAD in the earth system, and to further reduce the uncertainties in EAD simulations. Though much progress has been made, large discrepancies and knowledge gaps still exist among EAD simulations. The deficiencies and limitations that pertain to the performance of the EAD simulations referred to in the present study are also discussed.

关键词： East Asia dust aerosol dust modeling dust emissions long-range dust transport dust radiative forcing

基于张量化微结构表征的筏化镍基单晶高温合金疲劳寿命评估

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力学学报 2024年第7期56卷 2029-2050页

作者：罗诚袁荒清华大学航天航空学院北京100084 清华大学航空发动机研究院北京100084

镍基单晶高温合金的微观组织在长时高温服役下会发生粗化和筏化等微结构演化,导致力学性能衰减,影响航空发动机的服役寿命.文章研究了粗化和筏化镍基单晶DD6合金的低周疲劳行为,通过高温热暴露和预蠕变处理分别制备了粗化和筏化合金,针... 详细信息

镍基单晶高温合金的微观组织在长时高温服役下会发生粗化和筏化等微结构演化,导致力学性能衰减,影响航空发动机的服役寿命.文章研究了粗化和筏化镍基单晶DD6合金的低周疲劳行为,通过高温热暴露和预蠕变处理分别制备了粗化和筏化合金,针对具有不同微结构状态的合金开展了980℃下的等温低周疲劳试验,发现粗化和筏化合金的疲劳寿命相比初态合金显著下降.基于电子扫描显微镜和光学显微镜对试件断口表面进行了微观表征,揭示了筏化组织对低周疲劳损伤机理的影响.裂纹扩展路径受微结构状态影响,相比初态合金,粗化和筏化合金中I型微裂纹会更早发生偏折,沿晶体学面扩展而导致更早的疲劳失效.基于组构张量及其张量分解方案对合金的微结构进行了量化表征,提取了微结构的特征参数,进一步提出了一种新的微结构敏感的等温疲劳寿命预测模型.通过分别关联γ-基体相和γ′-强化相组构张量的独立分量,解耦了粗化和筏化对寿命的影响.在新模型中,γ/γ′微结构形态对低周疲劳的影响得到了较好描述,预测结果的准确性和保守性得到了显著提高.研究结果可为工程中镍基单晶涡轮叶片的强度设计和寿命评估提供理论指导.

关键词：单晶合金张量化表征筏化疲劳寿命评估

Degradation behavior of ZE21C magnesium alloy suture anchors and their effect on ligament-bone junction repair

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Bioactive Materials 2023年第8期26卷 128-141页

作者： Delin Ma Jun Wang Mingran Zheng yuan Zhang Junfei huang Wenxiang Li Yiwen Ding Yunhao Zhang Shijie Zhu Liguo Wang Xiaochao Wu Shaokang Guan School of Material Science and Engineering Zhengzhou UniversityZhengzhou450001China Henan Key Laboratory of Advanced Magnesium Alloys Zhengzhou450002China Key Laboratory of Advanced Materials Processing&Mold Ministry of EducationZhengzhou450002China Shimadzu(China)Co. LtdShenzhen BranchShenzhen528042China Zhengzhou Orthopedic Hospital Zhengzhou450053China

Current materials comprising suture anchors used to reconstruct ligament-bone junctions still have limitation in biocompatibility,degradability or mechanical *** alloys are potential bone implant materials,and Mg^(2+) has been shown to promote ligament-bone ***,we used Mg-2 wt.%Zn-0.5 wt.%Y-1 wt.%Nd-0.5 wt.%Zr(ZE21C)alloy and Ti6Al4V(TC4)alloy to prepare suture anchors to reconstruct the patellar ligament-tibia in SD *** studied the degradation behavior of the ZE21C suture anchor via in vitro and in vivo experiments and assessed its reparative effect on the ligament-bone *** vitro,the ZE21C suture anchor degraded gradually,and calcium and phosphorus products accumulated on its surface during *** vivo,the ZE21C suture anchor could maintain its mechanical integrity within 12 weeks of implantation in *** tail of the ZE21C suture anchor in high stress concentration degraded rapidly during the early implantation stage(0-4weeks),while bone healing accelerated the degradation of the anchor head in the late implantation stage(4-12weeks).Radiological,histological,and biomechanical assays indicated that the ZE21C suture anchor promoted bone healing above the suture anchor and fibrocartilaginous interface regeneration in the ligament-bone junction,leading to better biomechanical strength than the TC4 ***,this study provides a basis for further research on the clinical application of degradable magnesium alloy suture anchors.

关键词： ZE21C Suture anchor Degradation behavior Reparative effect Ligament-bone junction

Interplay of transcription factors and microRNAs during embryonic hematopoiesis

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Science China(Life Sciences) 2017年第2期60卷 168-177页

作者： Xueping Gong Ruihua Chao Pengxiang Wang Xiaoli huang Jingjing Zhang Xiaozhou Zhu Yanyang Zhang Xue Yang Chao Hou Xiangjun Ji Tieliu Shi yuan Wang Shanghai Key Laboratory of Regulatory Biology Institute of Biomedical Sciences and School of Life Sciences East China Normal University Shanghai 200241 China

Hematopoietic stem cells (HSCs), which are localized in the bone marrow of adult mammals, come from hematopoietic endothelium during embryonic stages. Although the basic processes of HSC generation and differentiation have been described in the past, the epigenetic regulation of embryonic hematopoiesis remains to be fully described. Here, by utilizing an in vitro differentiation system of mouse embryonic stem cells (ESCs), we identified more than 20 microRNAs that were highly enriched in embryonic hematopoietic cells, including some (e.g. miR-10b, miR-15b, and miR-27a) with previously unknown functions in blood formation. Luciferase and gene expression assays further revealed combinational binding and regulation of these microRNAs by key transcription factors in blood cells. Finally, bioinformatics and functional analyses supported an interactive regulatory control between transcription factors and microRNAs in hematopoiesis.

关键词： hematopoiesis embryonic stem cells microRNA

Diverting colostomy is an effective and reversible option for severe hemorrhagic radiation proctopathy

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World Journal of Gastroenterology 2020年第8期26卷 850-864页

作者： Zi-Xu yuan Qi-yuan Qin Miao-Miao Zhu Qing-Hua Zhong Alessandro Fichera Hui Wang Huai-Ming Wang Xiao-Yan huang Wu-Teng Cao Ye-Biao Zhao Lei Wang Teng-Hui Ma Department of Colorectal Surgery The Sixth Affiliated Hospital of Sun Yat-Sen UniversityGuangzhou 510655Guangdong ProvinceChina Guangdong Provincial Key Laboratory of Colorectal and Pelvic Floor Diseases Guangdong Institute of GastroenterologyThe Sixth Affiliated Hospital of Sun Yat-Sen UniversityGuangzhou 510655Guangdong ProvinceChina Department of Surgery University of North CarolinaChapel HillNC 27514United States Department of Radiology The Sixth Affiliated Hospital of Sun Yat-Sen UniversityGuangzhou 510655Guangdong ProvinceChina

BACKGROUND Severe chronic radiation proctopathy(CRP) is difficult to *** To evaluate the efficacy of colostomy and stoma reversal for *** To assess the efficacy of colostomy in CRP,patients with severe hemorrhagic CRP who underwent colostomy or conservative treatment were *** with tumor recurrence,rectal-vaginal fistula or other types of rectal fistulas,or who were lost to follow-up were *** bleeding,hemoglobin(Hb),endoscopic features,endo-ultrasound,rectal manometry,and magnetic resonance imaging findings were *** of life before stoma and after closure reversal was scored with *** functions were assessed using the CRP symptom scale,which contains the following items:Watery stool,urgency,perianal pain,tenesmus,rectal bleeding,and fecal/gas *** A total of 738 continual CRP patients were *** exclusion,14 patients in the colostomy group and 25 in the conservative group were included in the final *** Hb was only 63 g/L ± 17.8 g/L in the colostomy group compared to 88.2 g/L ± 19.3 g/L(P < 0.001) in the conservative ***14 patients in the former group achieved complete remission of bleeding,and the colostomy was successfully reversed in 13 of 14(93%),excepting one very old *** median duration of stoma was 16(range:9-53) *** Hb level increased gradually from 75 g/L at 3 mo,99 g/L at 6 mo,and 107 g/L at 9 mo to111 g/L at 1 year and 117 g/L at 2 years after the stoma,but no bleeding cessation or significant increase in Hb levels was observed in the conservative *** telangiectasia and bleeding were greatly *** showed decreased vascularity,and magnetic resonance imaging revealed an increasing presarcal space and thickened rectal *** functions and quality of life were significantly improved after stoma reversal,when compared to those before stoma *** Diverting colostomy is a very effec

关键词： Chronic radiation proctitis Hemorrhage Colostomy Anorectal function Quality of life

Ultrasonography of splenic abnormalities

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World Journal of Gastroenterology 2005年第26期11卷 4061-4066页

作者： Ming-Jen Chen Ming-Jer huang Wen-Hsiung Chang Tsang-En Wang Horng-yuan Wang Cheng-Hsin Chu Shee-Chan Lin Shou-Chuan Shih Division of Gastroenterology Department of Internal Medicine Mackay Memorial Hospital Mackay Medicine Nursing and Management College Taipei Taiwan China Division of Hematology and Oncology Department of Internal Medicine Mackay Memorial Hospital Taipei Taiwan China

AIM: This report gives a comprehensive overview of ultrasonography of splenic abnormalities. Certain ultrasonic features are also discussed with pathologic ***: We review the typical ultrasonic characteristics of a wide range of splenic lesions, illustrating them with images obtained in our institution from 2000 to *** hundred and three patients (47 men, 56 women),with a mean age of 54 years (range 9-92 years), were found to have an abnormal ultrasonic pattern of ***: We describe the ultrasonic features of various splenic lesions such as accessory spleen, splenomegaly,cysts, cavernous hemangiomas, lymphomas, abscesses,metastatic tumors, splenic infarctions, hematomas, and rupture, based on traditional gray-scale and color Doppler ***: Ultrasound is a widely available, noninvasive,and useful means of diagnosing splenic abnormalities. A combination of ultrasonic characteristics and clinical data may provide an accurate diagnosis. If the US appearance alone is not enough, US may also be used to guide biopsy of suspicious lesions.

关键词： Ultrasonography Ultrasound Splenic abnormalities Spleen

Milk-derived exosomes exhibit versatile effects for improved oral drug delivery

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Acta Pharmaceutica Sinica B 2022年第4期12卷 2029-2042页

作者： Lei Wu Lingling Wang Xi Liu Yuli Bai Ruinan Wu Xiang Li Yutong Mao Ling Zhang Yongxiang Zheng Tao Gong Zhirong Zhang yuan huang Key Laboratory of Drug Targeting and Drug Delivery System Ministry of EducationWest China School of PharmacySichuan UniversityChengdu 610041China Sichuan University College of Polymer Science and EngineeringChengdu 610041China Sichuan University West China School of Pharmacy Chengdu 610041China

As endogenous courier vesicles,exosomes play crucial roles in macromolecule transmission and intercellular ***,exosomes have drawn increasing attention as biomimetic drug-delivery vehicles over the past few ***,few studies have investigated the encapsulation of peptide/protein drugs into exosomes for oral ***,the mechanisms underlying their biomimetic properties as oral delivery vehicles remain ***,insulin-loaded milk-derived exosomes(EXO@INS)were fabricated and the in vivo hypoglycemic effect was investigated on type I diabetic ***,EXO@INS(50 and 30 IU/kg)elicited a more superior and more sustained hypoglycemic effect compared with that obtained with subcutaneously injected *** mechanism studies indicated that the origin of excellent oral-performance of milk-derived exosomes combined active multi-targeting uptake,pH adaptation during gastrointestinal transit,nutrient assimilation related ERK1/2 and p38 MAPK signal pathway activation and intestinal mucus *** study provides the first demonstration that multifunctional milk-derived exosomes offer solutions to many of the challenges arising from oral drug delivery and thus provide new insights into developing naturally-equipped nanovehicles for oral drug administration.

关键词： Milk-derived exosomes Oral drug delivery system Apical-to-basolateral transport pH Adaptation Biomimetic vehicles Insulin Transcytosis Signal regulation

Population-based carrier screening and prenatal diagnosis of fragile X syndrome in East Asian populations

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Journal of Genetics and Genomics 2021年第12期48卷 1104-1110页

作者： Qiwei Guo Yih-yuan Chang Chien-Hao huang Yu-Shan Hsiao Yu-Chiao Hsiao I-Fan Chiu Yulin Zhou Haixia Zhang Tsang-Ming Ko United Diagnostic and Research Center for Clinical Genetics Women and Children's HospitalSchool of Medicine&School of Public HealthXiamen UniversityXiamenFujian 361102China Genephile Bioscience Laboratory Ko's Obstetrics and GynecologyTaipei 100TaiwanChina Biofast Biotechnology Co. Ltd.XiamenFujian 361102China

Identification of carriers of fragile X syndrome(FXS) with the subsequent prenatal diagnosis and knowledge of FXS-associated genetic profiles are essential for intervention in specific populations. We report the results of carrier screening of 39,458 East Asian adult women and prenatal diagnosis from 87 FXS *** prevalence of FXS carriers and full mutation fetuses was estimated to be 1/581 and 1/3124 in East Asian populations, respectively. We confirmed the validity of the current threshold of CGG trinucleotide repeats for FMR1 categorization;the integral risks of full mutation expansion were approximately 6.0%,43.8%, and 100% for premutation alleles with 55—74, 75—89, and ≥ 90 CGG repeats, respectively. The protective effect of AGG(adenine-guanine-guanine nucleotides) interruption in East Asian populations was validated, which is important in protecting premutation alleles with 75—89 CGG repeats from full mutation expansion. Finally, family history was shown not an effective indicator for FXS carrier screening in East Asian populations, and population-based screening was more cost-effective. This study provides an insight into the largest carrier screening and prenatal diagnosis for FXS in East Asian populations to date. The FXSassociated genetic profiles of East Asian populations are delineated, and population-based carrier screening is shown to be promising for FXS intervention.

关键词： AGG interruption East Asian population Fragile X syndrome Population-based carrier screening Prenatal diagnosis Cost-effectiveness analysis