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Chemical derivatization strategies for enhancing the HPLC analytical performance of natural active triterpenoids

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Journal of Pharmaceutical Analysis 2024年第3期14卷 295-307页

作者： xiao-Feng Huang Ying Xue Li Yong tian-tian Wang Pei luo lin-Sen Qing Chengdu Institute of Biology Chinese Academy of SciencesChengdu610041China State Key Laboratory for Quality Research in Chinese Medicines Macao University of Science and TechnologyMacaoChina Sichuan Center for Disease Control and Prevention Chengdu610041China University of Chinese Academy of Sciences Beijing100049China

Triterpenoids widely exist in nature,displaying a variety of pharmacological *** triterpenoids in different matrices,especially in biological samples holds great ***-performance liquid chromatography(HPLC)has become the predominant method for triterpenoids analysis due to its exceptional analytical ***,due to the structural similarities among botanical samples,achieving effective separation of each triterpenoid proves challenging,necessitating significant improvements in analytical ***,triterpenoids are characterized by a lack of ultraviolet(UV)absorption groups and chromophores,along with low ionization efficiency in mass ***,routine HPLC analysis suffers from poor *** derivatization emerges as an indispensable technique in HPLC analysis to enhance its *** the structural characteristics of triterpenoids,various derivatization reagents such as acid chlorides,rhodamines,isocyanates,sulfonic esters,and amines have been employed for the derivatization analysis of *** review comprehensively summarized the research progress made in derivatization strategies for HPLC detection of ***,the limitations and challenges encountered in previous studies are discussed,and future research directions are proposed to develop more effective derivatization methods.

关键词： Triterpenoid HPLC Derivatization Quantification

Enrichment, isolation and identification of sulfur-oxidizing bacteria from sulfide removing bioreactor

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Journal of Environmental Sciences 2013年第7期25卷 1393-1399页

作者： Jianfei luo Guoliang tian Weitie lin College of Bioscience and Bioengineering South China University of Technology

Sulfur-oxidizing bacteria （SOB） are the main microorganisms that participate in the natural sulfur cycle. To obtain SOBwith high sulfur-oxidizing ability under aerobic or anaerobic conditions, aerobic and anaerobic enrichmentswere carried out. Denaturing gradient gel electrophoresis （DGGE） profiles showed that the microbial community changed according to the thiosulfate utilizationduring enrichments, and Rhodopseudomonas and Halothiobacilluswere the predominant bacteria in anaerobic enrichment and aerobic enrichment, respectively,which mainly contributed to the thiosulfate oxidization in the enrichments. Based on the enriched cultures, six isolateswere isolated from the aerobic enrichment and four isolateswere obtained from the anaerobic enrichment. Phylogenetic analysis suggested the 16S rRNA gene of isolates belonged to the genus Acinetobacter, Rhodopseudomonas, Pseudomonas, Halothiobacillus,0chrobactrum, Paracoccus, Thiobacillus, and Alcaligenes, respectively. The tests suggested isolates related to Halothiobacillus and Rhodopseudomonas had the highest thiosulfate oxidizing ability under aerobic or anaerobic conditions, respectively; Paracoccus and Alcaligenes could aerobically and anaerobically oxidize thiosulfate. Based on the DGGE and thiosulfate oxidizing ability analysis, Rhodopseudomonas and Halothiobacilluswere found to be the main SOB in the sulfide-removing reactor, andwere responsible for the sulfur-oxidizing in the treatment system.

关键词： sulfur-oxidizing bacteria (SOB) thiosulfate-oxidizing microbial community enrichment isolation

Effectiveness of dietary xylo-oligosaccharides for broilers fed a conventional corn-soybean meal diet

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Journal of Integrative Agriculture 2015年第10期14卷 2050-2057页

作者： SUO Hai-qing LU lin XU Guo-hui xiao lin CHEN xiao-gang XIA rui-rui ZHANG Li-yang luo Xu-gang Mineral Nutrition Research Division Institute of Animal Sciences Chinese Academy of Agricultural Sciences High-Technology Development Zone Functional Sugar Engineering Research Center of Shandong Province High-Technology Development Zone Shandong Key Laboratory of Straw and Stover Biorefinement Technologies

An experiment was conducted to investigate the effect of dietary supplementation of xylo-oligosaccharides（XOS） on growth performance, meat quality, immune functions, duodenal morphology and intestinal microbial populations of broilers fed a conventional corn-soybean meal basal diet. A total of 450 1-day-old commercial Arbor Acres male broiler chicks were randomly allocated by bodyweight to 1 of 5 treatments with 6 replicate cages（15 broilers per cage） for each of 5 treatments in a completely randomized design. Chicks were fed the basal corn-soybean meal diets supplemented with 0, 25, 50, 75, or 100 mg of XOS kg–1 of diet, respectively, for an experimental duration of 42 days. The results showed that supplementation of XOS affected feed conversion rate（feed/gain, F/G） during days 22–42 and 1–42（P〈0.03）, drip loss in thigh muscle（P=0.02）, and duodenal crypt depth（P=0.005） on day 42, but had no effect（P〉0.05） on all other measured indices. The chicks fed the diet supplemented with 100 mg of XOS kg–1 had the lowest（P〈0.05） F/G and drip loss in thigh muscle. The drip loss in thigh muscle decreased linearly（P=0.003） as the supplemented XOS increased. Duodenal crypt depth decreased（P〈0.05） at the supplemental level of 75 mg of XOS kg–1. The results indicate that dietary supplementations of 75 and 100 mg of XOS kg–1 are beneficial to broilers fed a conventional corn-soybean meal diet.

关键词： xylo-oligosaccharide effectiveness F/G drip loss broiler chick

Superomniphobic surfaces for easy-removals of environmentalrelated liquids after icing and melting

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Nano Research 2023年第2期16卷 3267-3277页

作者： Lizhong Wang Ze tian xiao luo Changhao Chen Guochen Jiang Xinyu Hu rui Peng Hongjun Zhang Minlin Zhong Laser Materials Processing Research Center Key Laboratory for Advanced Materials Processing Technology(Ministry of Education)Joint Research Center for Advanced Materials&Anti-icing of Tsinghua University(SMSE)-AVIC ARISchool of Materials Science and EngineeringTsinghua UniversityBeijing 100084China

Superhydrophobic surfaces often lose the easy-removal ability of liquids during icing&melting cycles due to the impalement phenomena of air *** for the most common mixed liquids in normal life,their difficult-removals after icing and melting have brought colossal troubles in the fields of aviation,energy,biomedicine,*** we adopt the ultrafast laser to fabricate the optimal micro-nanostructured surfaces,realizing excellent superomniphobicity for seven environmental-related *** is demonstrated that different droplets on the surfaces recover well to the original Cassie-Baxter state after melting,and can be removed easily at low tilted *** ice adhesion strengths of the seven liquids as low as 5 kPa and the micro-nanostructure durability ensure the long-term easy-removal after *** with the ice adhesion strength of untreated surfaces(264.4±17.6 kPa),those of our designed surfaces have decreased by over 50 *** and melting processes are investigated to reveal the easy-removal mechanisms that specifically distributed solutes and bubbles after icing impact downwards significantly to accelerate the recovery of the Cassie–Baxter state during melting.A series of environmental-related durability experiments including continuous icing&melting cycles,long-term salt spray,and high-pressure water jet impact further demonstrate the surfaces promising for real applications.

关键词： superomniphobic surfaces easy-removal environmental-related liquids icing melting

Optimality Conditions for Generalized Convex Nonsmooth Uncertain Multi-objective Fractional Programming

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Journal of the Operations Research Society of China 2023年第4期11卷 809-826页

作者： xiao Pan Guo-lin Yu tian-tian Gong School of Mathematics and Information Science North Minzu UniversityYinchuan750021NingxiaChina

This paper aims at studying optimality conditions of robust weak efficient solutions for a nonsmooth uncertain multi-objective fractional programming problem(NUMFP).The concepts of two types of generalized convex function pairs,called type-I functions and pseudo-quasi-type-I functions,are introduced in this paper for(NUMFP).Under the assumption that(NUMFP)satisfies the robust constraint qualification with respect to Clarke subdifferential,necessary optimality conditions of the robust weak efficient solution are *** optimality conditions are obtained under pseudo-quasi-type-I generalized convexity ***,we introduce the concept of robust weak saddle points to(NUMFP),and prove two theorems about robust weak saddle *** main results in the present paper are verified by concrete examples.

关键词： Multi-objective fractional programming Robust weak efficient solution Generalized convex function Optimality condition Saddle point

B、N小原子对Dy(Gd)基合金非晶形成能力和晶化动力学的影响

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稀有金属材料与工程 2010年第5期39卷 862-866页

作者：田瑞罗林丁铁锁肖学山上海大学上海200072

采用水冷铜模吸铸法制备添加B、N小原子的Dy(Gd)基合金系样品,利用X射线衍射(XRD)仪检测合金的相结构,利用示差扫描量热(DSC)仪研究合金的玻璃转变和晶化行为,用Kissinger和Arrehenius方程分别计算出合金的晶化激活能、频率因子、晶化... 详细信息

采用水冷铜模吸铸法制备添加B、N小原子的Dy(Gd)基合金系样品,利用X射线衍射(XRD)仪检测合金的相结构,利用示差扫描量热(DSC)仪研究合金的玻璃转变和晶化行为,用Kissinger和Arrehenius方程分别计算出合金的晶化激活能、频率因子、晶化速率常数等晶化动力学参数。结果表明:Dy31Gd25Co20Al24合金中添加小原子B和N,晶化模式发生改变;合金的过冷液相区和晶化激活能先减小后增大;加入B原子,合金的晶化速率常数先增大后减小,加入N原子,合金的晶化速率常数先减小后增大。

关键词：玻璃形成能力晶化动力学晶化激活能 Dy基非晶

Anti-hepatoma activity and mechanism of ursolic acid and its derivatives isolated from Aralia decaisneana

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World Journal of Gastroenterology 2006年第6期12卷 874-879页

作者： Ze tian Geng lin rui-Xia Zheng Feng Huang Meng-Su Yang Pei-Gen xiao Department of Pharmacology Institute of Medicinal PlantDevelopment Chinese Academy of Medical Sciences PekingUnion Medical College Beijing 100094 China Departm'entof Biology and Chemistry CityUniversity of Hong Kong Kowloon Hong Kong China

AIM： To investigate the anti-tumor activity of ursolic acid （UA） and its derivatives isolated from Aralia decaisneana on hepatocellular carcinoma both in vitro and in vivo. METHODS： In vivo cytotoxicity was first screened by 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide （MTT） assay. Morphological observation, DNA ladder, flow cytometry analysis, Western blot and real time PCR were employed to elucidate the cytotoxic mechanism of UA. Implanted mouse hepatoma H22 was used to evaluate the growth inhibitory effect of UA in vivo . RESULTS： UA could significantly inhibit the proliferation of HepG2 and its drug-resistance strain, R-HepG2 cells, but had no inhibitory effect on primarily cultured normal mouse hepatocytes whereas all the six derivatives of UA could not inhibit the growth of all tested cell lines. Further study on mechanism demonstrated that apoptosis and G0/G1 arrest were involved in the cytotoxicity and cleavage of poly-（ADP-ribose）- polymerase （PARP）. Downregulation of cyclooxygenase-2 （COX-2） protein and upregulation of heat shock protein （HSP） 105 mRNA correlated to the apoptosis of HepG2 cells treated with UA. In addition, UA also could inhibit the growth of H22 hepatoma in vivo. CONCLUSION： UA is a promising anti-tumor agent, but further work needs to be done to improve its solubility.

关键词： Aralia decaisneana Ursolic acid Hepatoma

Effects of adverse pressure gradient on Reynolds stresses inturbulent boundary layers

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航空动力学报 2017年第2期32卷 463-469页

作者： luo xiao-tian ZHANG Ce MA Wei TENG Jin-fang School of Aeronautics and Astronautics Shanghai Jiao Tong University

The effects of adverse pressure gradient(APG)on Reynolds stresses in turbulent boundary layers(TBLs)with APG were *** difficulty of this work was attributable to the Reynolds stresses in TBLs with APG under two combined effects,i.e.:effect of upstream flow and effect of *** effect of upstream flow is an inherent effect no matter pressure gradient exists or *** individual effect was analyzed from absolute developments of Reynolds stresses in TBLs with zero pressure gradient(ZPG)*** of APG was then analyzed from absolute developments of Reynolds stresses in TBLs with *** showed that,for absolute development of mean streamwise Reynolds stresses,APG accelerated its development in TBL with ZPG;for absolute development of mean normal or shear Reynolds stresses,APG increased their magnitude in the outer part,and decreased their extent of large value region.

关键词： turbulent boundary layer adverse pressure gradient zero pressure gradient Reynolds stresses flat plate

Influence of microstructure on the corrosion resistance of Fe–44Ni thin films

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International Journal of Minerals,Metallurgy and Materials 2016年第6期23卷 691-697页

作者： lin Lu tian-cheng Liu xiao-gang Li Corrosion and Protection Center University of Science and Technology Beijing Central Iron and Steel Research Institute

An Fe–44Ni nanocrystalline（NC） alloy thin film was prepared through electrodeposition. The relation between the microstructure and corrosion behavior of the NC film was investigated using electrochemical methods and chemical analysis approaches. The results show that the NC film is composed of a face-centered cubic phase（γ-（Fe,Ni）） and a body-centered cubic phase（α-（Fe,Ni）） when it is annealed at temperatures less than 400℃. The corrosion resistance increases with the increase in grain size, and the corresponding corrosion process is controlled by oxygen reduction. The NC films annealed at 500℃ and 600℃ do not exhibit the same pattern, although their grain sizes are considerably large. This result is attributed to the existence of an anodic phase, Fe0.947Ni0.054, in these films. Under this condition, the related corrosion process is synthetically controlled by anodic dissolution and depolarization.

关键词： iron nickel alloys nanocrystalline alloys thin films phase composition corrosion resistance annealing temperature grain size