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Peptide Deravatives as New Chiral Ligands for Enantioselective Phenylacetylene Addition to Aldehydes

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有机化学 2004年第Z1期24卷 162-页

作者： ZHOU,Yi-feng GAO,Yan-feng kang,Yong-feng HAN,Zhi-Jian YAN,Wen-Jin NI,Ming WANG,Rui State Key Laboratory of Applied Organic Chemistry Department of Biochemistry & Molecular Biology School of Life Sciences Lanzhou University Lanzhou 730000 State Key Laboratory of Applied Organic Chemistry Department of Biochemistry & Molecular Biology School of Life Sciences Lanzhou University Lanzhou 730000 State Key Laboratory of Applied Organic Chemistry Department of Biochemistry & Molecular Biology School of Life Sciences Lanzhou University Lanzhou 730000 State Key Laboratory of Applied Organic Chemistry Department of Biochemistry & Molecular Biology School of Life Sciences Lanzhou University Lanzhou 730000 State Key Laboratory of Applied Organic Chemistry Department of Biochemistry & Molecular Biology School of Life Sciences Lanzhou University Lanzhou 730000 State Key Laboratory of Applied Organic Chemistry Department of Biochemistry & Molecular Biology School of Life Sciences Lanzhou University Lanzhou 730000 State Key Laboratory of Applied Organic Chemistry Department of Biochemistry & Molecular Biology School of Life Sciences Lanzhou University Lanzhou 730000

　　The asymmetric addition of alkynylzinc to aldehydes is an important method of synthesizing chiral propargyl alcohols, which are important precursors to many chiral organic compounds. Recently, many significant chiral ligands in this area have been disclosed.[1] Use of a short peptide as a catalyst would allow expansion beyond the (still uncharted) repertoire of single amino acids, while conserving the advantages of a small molecule catalyst. To the best of our knowledge,no results of peptide derivatives as chiral ligands in this reaction has been disclosed to date.[2] Herein, we report the initial results of peptide derivatives, which have been used directly as a chiral ligand in this reaction (Scheme 1).……

关键词： chiral ligands asymmetric addition organic compounds small molecule amino acids method of

CONTACT ALGORITHMS FOR CONTACT DYNAMICAL SYSTEMS

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Journal of Computational Mathematics 1998年第1期16卷 1-14页

作者： kang feng 中科院计算数学与科学工程计算所北京

In this paper, we develop a general way to construct contact algorithms for contact dynamical systems. Such an algorithm requires the corresponding step transition map preserve the contact structure of the underlying contact phase space. The constructions are based on the correspondence between the contact geometry of R2n+1 and the conic symplectic one of R2n+2 and therefore, the algorithms are derived naturally from the symplectic algorithms of Hamiltonian systems.

关键词： contact algorithms contact systems conic symplectic geometry generating functions

Analysis of the anti-T2DM components in dichloromethane fraction of Schisandra sphenanthera and its mechanism

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Traditional Medicine Research 2025年第1期10卷 27-43页

作者： Shi-Bo feng Hai-Hui Jiang Hui-Li kang Yi Jiang Hua-Wei Zhang Xiao-Mei Song Yu-Ze Li Wen-Li Huang Dong-Dong Zhang Chong Deng School of Pharmacy Shaanxi University of Chinese MedicineXianyang 712046China School of Pharmacy and Shaanxi Qinling Application Development and Engineering Center of Chinese Herbal Medicine Shaanxi University of Chinese MedicineXianyang 712046China Key Laboratory for Research and Development of“Qin Medicine”of Shaanxi Administration of Traditional Chinese Medicine Xianyang 712046China Shaanxi Key Laboratory of Research and Application of“Taibai Qi Yao” Xianyang 712046China

Background:The type 2 diabetes mellitus(T2DM)pharmacodynamic study of various parts of Schisandra sphenanthera was conducted in the previous stage,and it was found that dichloromethane extracted part(SDP)had a significant hypoglycemic ***,the components of SDP were analyzed,and the specific mechanism of its anti-T2DM was ***:We used a high-fat,high-sugar diet in combination with streptozotocin to induce a T2DM rat model,and the model rats were divided into two groups according to body weight and blood ***,oral glucose tolerance test,fasting blood glucose,low density lipoprotein cholesterol,superoxide dismutase,insulin,glycated hemoglobin,total cholesterol,nonesterified free fatty acids,alanine aminotransferase,high-density lipoprotein cholesterol,aspartate aminotransferase,malondialdehyde,and glutathione peroxidase were measured,organ indices were calculated,and pathological sections of pancreas and liver were *** 16S rRNA V3–V4 region of intestinal flora was sequenced to explore the effect of SDP on biochemical indicators and intestinal *** on the above indicators,the anti-T2DM mechanism of SDP in Schisandra sphenanthera was ***:After six weeks of administration,the biochemical indices of diabetic rats were diminished compared to the control *** SDP could significantly increase the gut microbialα-diversity index,resulting in significant changes in the flora of T2DM rats,with increased richness and diversity,reduced harmful flora,and significantly back-regulated the levels of acetic acid,propionic acid,and butyric ***:SDP can improve the symptoms associated with elevated blood glucose,dyslipidemia,elevated fasting insulin levels,and damaged glucose tolerance in *** against T2DM may be through the control of intestinal flora to normalize and exert anti-diabetic effect;its main active components may be lignans and terpenoids.

关键词： Schisandra sphenanthera T2DM intestinal flora HPLC

Potential role of tanycyte-derived neurogenesis in Alzheimer's disease

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Neural Regeneration Research 2025年第6期20卷 1599-1612页

作者： Guibo Qi Han Tang Jianian Hu Siying kang Song Qin Department of Anatomy Histologyand EmbryologySchool of Basic Medical SciencesFudan UniversityShanghaiChina State Key Laboratory of Medical Neurobiology and MOE Frontiers Center for Brain Science Fudan UniversityShanghaiChina

Tanycytes, specialized ependymal cells located in the hypothalamus, play a crucial role in the generation of new neurons that contribute to the neural circuits responsible for regulating the systemic energy balance. The precise coordination of the gene networks controlling neurogenesis in naive and mature tanycytes is essential for maintaining homeostasis in adulthood. However, our understanding of the molecular mechanisms and signaling pathways that govern the proliferation and differentiation of tanycytes into neurons remains limited. This article aims to review the recent advancements in research into the mechanisms and functions of tanycyte-derived neurogenesis. Studies employing lineage-tracing techniques have revealed that the neurogenesis specifically originating from tanycytes in the hypothalamus has a compensatory role in neuronal loss and helps maintain energy homeostasis during metabolic diseases. Intriguingly,metabolic disorders are considered early biomarkers of Alzheimer's disease. Furthermore,the neurogenic potential of tanycytes and the state of newborn neurons derived from tanycytes heavily depend on the maintenance of mild microenvironments, which may be disrupted in Alzheimer's disease due to the impaired blood–brain barrier ***, the specific alterations and regulatory mechanisms governing tanycyte-derived neurogenesis in Alzheimer's disease remain unclear. Accumulating evidence suggests that tanycyte-derived neurogenesis might be impaired in Alzheimer's disease, exacerbating neurodegeneration. Confirming this hypothesis, however, poses a challenge because of the lack of long-term tracing and nucleus-specific analyses of newborn neurons in the hypothalamus of patients with Alzheimer's disease. Further research into the molecular mechanisms underlying tanycyte-derived neurogenesis holds promise for identifying small molecules capable of restoring tanycyte proliferation in neurodegenerative diseases. This line of investigation could pro

关键词： Alzheimer's disease blood–brain barrier ependymoglial cells hypothalamus metabolic diseases neural stem cells neurogenesis neuroinflammatory diseases neurons tanycyte

Experimental research on grouser traction of deep-sea mining machine

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Applied Mathematics and Mechanics(English Edition) 2015年第9期36卷 1243-1252页

作者： Wenbo MA Qiuhua RAO kang feng feng XU School of Civil Engineering Central South University

The traction characteristics of the grouser, cutting the simulative soil of deepsea sediment, with different tooth widths, tooth heights, and ground pressures are studied with traction characteristic test apparatus. A traction-displacement model is obtained by combining the analysis of the cutting mechanism. The results show that the tractiondisplacement curves of grousers with different tooth widths, tooth heights, and ground pressures have the same changing trend, which matches the Wong traction model. Their sensitivity coefficient and shear modulus are slightly fluctuated. Therefore, the average values can be used as the traction model parameters. The maximum traction of the grouser with a two-side edge and a 10 mm tooth width increment changing with the tooth height and ground pressure can be determined according to the grousers with different tooth widths. By combining the traction model parameters, the traction-displacement curve of the grouser with a certain group values of tooth width, tooth height, and ground pressure can be predicted. Therefore, the slip of the mining machine can be prevented to improve the mining efficiency.

关键词： deep-sea sediment simulative soil traction test deep-sea mining machine,grouser traction model

Application of low-temperature thermochronology on ore deposits preservation framework in South China:a review

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Acta Geochimica 2022年第2期41卷 165-184页

作者： kang Min Jian-feng Gao State Key Laboratory of Ore Deposit Geochemistry Institute of GeochemistryChinese Academy of SciencesGuiyang 550081China University of Chinese Academy of Sciences Beijing 100049China

South China can be divided into four metallogenic belts:The Middle-Lower Yangtze Metallogenic Belt(MLYB),Qinzhou-Hangzhou Metallogenic Belt(QHMB),Nanling Metallogenic Belt(NLMB),and Wuyi Metallogenic Belt(WYMB).The major mineralization in the four metallogenic belts is granite-related Cu–Au–Mo and porphyrite Fe-apatite,porphyry Cu(Au),and epithermal Pb–Zn–Ag,hydrothermal Cu–Au–Pb–Zn–Ag,and granite-related skarn-type and quartz-veins W–Sn,***-temperature thermochronology,including fissiontrack and U-Th/He dating,has been widely used to constrain tectonic thermal evolution and ore deposits *** fission-track annealing and He diffusion kinetics in accessory minerals,such as zircon and apatite,is essential for dating and *** this study,previous zircon fission-track(ZFT)and apatite fission-track(AFT)ages in South China were *** result shows that the ZFT ages are mainly concentrated at140–90 Ma,and the AFT ages are mainly distributed at70–40 *** age distribution and inversion temperature–time paths reveal heterogeneous exhumation histories in South *** MLYB experienced Late CretaceousCenozoic extremely slow exhumation after rapid cooling in the Early *** northern QHMB(*** southern Anhui province to the Hangzhou Bay)had a relatively faster rate of uplifting and denudation than the southern QHMB in the ***,the northern QHMB rapidly exhumed,while the continuously slow exhumation operated the southern QHMB in the *** southern NLMB had a more rapid cooling rate than the northern NLMB during the Cretaceous time,and the whole NLMB experienced rapid cooling in the Cenozoic,except that the southern Hunan province had the most rapid cooling *** WYMB possibly had experienced slow exhumation since the Late *** exhumation thickness of the four metallogenic belts since90 Ma is approximately calculated as follows:the MLYB≤3.5 km,the northern QHMB concentrated at

关键词： Low-temperature thermochronology Fissiontrack annealing and He diffusion kinetics South China Exhumation history Deposits preservation

Dynamical model of encapsulated gas microbubble under ultrasound based on elastic mechanics

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Science China(Physics,Mechanics & Astronomy) 2017年第7期60卷 60-69页

作者： kang Chen JiangTao feng KaiYu Xu Shanghai Institute of Applied Mathematics and Mechanics Shanghai University Shanghai 200072 China College of Sciences Shanghai University Shanghai 200444 China

Based on the theory of elastic mechanics, a dynamical model of an encapsulated gas microbubble under ultrasound is *** dynamical motion of the microbubble is divided into three states: buckled, elastic, and ruptured. The model describes the compression-only behavior appropriately and derives the transient variation of the resonance frequency of the damped oscillation and the relation between the critical rupture radius and initial outer radius. The normal stress in the tangential direction plays the principal role in the rupture and buckling of the encapsulating shell, resulting in likely rupture for a larger microbubble and resistance to rupture for a thicker-shell microbubble. Comparison of proposed dynamical model with Marmottant's model has been given. The dynamical model can be employed in ultrasound medical diagnostics and therapy of drug incorporation or extravasation through further understanding the influence of the encapsulating shell.

关键词： dynamical model encapsulated gas microbubble ultrasound buckle rupture

State of the art of bioimplants manufacturing： part II

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Advances in Manufacturing 2018年第1期6卷 137-154页

作者： Cheng-Wei kang feng-Zhou Fang Centre of MicroNano Manufacturing Technology (MNMT- Dublin) University College Dublin Belfield Ireland State Key Laboratory of Precision Measuring Technology & Instruments Centre of MicroNano Manufacturing Technology Tianjin University Tianjin 300072 People's Republic of China

The manufacturing of bioimplants not only involves selecting proper biomaterials with satisfactory bulk physicochemical properties, but also requires special treatments on surface chemistry or topography to direct a desired host response. The lifespan of a bioimplant is also critically restricted by its surface properties. Therefore, developing proper surface treatment technologies has become one of the research focuses in biomedical engineering. This paper covers the recent progress of surface treatment of bioimplants from the aspects of coating and topography modification. Pros and cons of various tech- nologies are discussed with the aim of providing the most suitable method to be applied for different biomedical products. Relevant techniques to evaluate wear, corrosion and other surface properties are also reviewed.

关键词： Bioimplant Precision manufacturing Surfacetreatment Evaluation

Effects of irrigation efficiency on chemical transport processes

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Science China(Technological Sciences) 2009年第11期52卷 3287-3292页

作者： WANG kang ZHANG RenDuo SHENG feng State Key Laboratory of Water Resources and Hydropower Engineering Science Wuhan UniversityWuhan 430072China School of Environmental Science and Engineering Sun Yat-sen UniversityGuangzhou 510275China

Irrigation practices greatly affect sustainable agriculture development. In this study, we investigated the effects of irrigation efficiency on water flow and chemical transport in soils, which had significant impact on the environment. Field dye staining experiments were conducted at different soils with various irrigation amount. Image analysis was conducted to study the heterogeneous flow patterns and their relationships with the irrigation efficiency. Irrigation efficiency and its environmental effects were evaluated using various indictors, including application efficiency, deep percolation ratio, storage efficiency, and uniformity. Under the same irrigation condition, soil chemical distributions were more heterogeneous than soil water distributions. The distributions were mainly affected by soil texture, initial soil water content, and irrigation amount. Storage efficiency, irrigation uniformity, and deep percolation ratio increased with irrigation amount. Since the chemical distribution uniformity was lower than the water uniformity, the amount of chemical leaching increased sharply with decrease of irrigation uniformity, which resulted in high environmental risks of groundwater pollution.

关键词： irrigation efficiency chemical transport groundwater pollution