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Kigelia africana Fruit:Constituents,Bioactivity, and Reflection on Composition Disparities

World Journal of Traditional Chinese Medicine 2017年第4期3卷 1-6页

作者： Ahmed galal Osman Zulfiqar Ali amar g.chittiboyina lkhlas A.Khan National Center for Natural Products Research University of Mississippi Department of BioMolecular Sciences Division of Pharmacognosy School of PharmacyUniversity of Mississippi

Objective: Kigelia africana, a tropical tree, which has long been used in African traditional medicine. The objective of the current study has been identifying the constituents of K. africana and verifying its utilities in traditional medicine. Materials and Methods: The methanol extract of K. africana fruits was subjected to chromatographic fractionation utilizing different techniques. The methanol extract together with the isolated compounds were tested for their bioactivities in a series of cell-based assays. Results: The current work led to isolation and characterization of nine constituents including iridoid glycosides, phenylpropanoid derivatives, and a eucommiol derivative. The hexanes extract caused inhibition of the opportunistic yeast; Cryptococcus neoformans Pinh. The chloroform extract exhibited substantial antileishmanial activity of Leishmania donovani. Verminoside(1) showed weak inhibition of the CB1, CB2, and Kappa opioid receptors. Compound 4 exhibited weak inhibition of the Kappa and Mu opioid receptors. The hexanes and the chloroform extracts of K. africana exhibited inhibitory activity against the pathogenic parasite Trypanosoma brucei. The ethyl acetate extract showed the same activity. Conclusions: This is the first report on the isolation of coniferyl 4-0-(3-D-glucopyranoside(7), a eucommiol derivative(crescentin IV)(6), and 6-feruloylcatalpol(4) from the genus Kigelia. It is also the first report on the separation of ajugol(2), catalpol(3), and specioside(5) from the fruits of K. africana. Revision of the^1 H and ^(13)C-NMR spectra of 6-feruloylcatalop(4) and 6-p-hydroxycinnamoylcatalpol(5, specioside) is described. Further, the results of the in vitro assays corroborate the traditional utility of this plant in medicine.

关键词： Anticryptoccocal antileishmanial cannabinoid receptors Kigelia africana opioid receptors

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High-speed silicon photonic electro-optic Kerr modulation

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Photonics Research 2024年第1期12卷 51-60页

作者： JONATHAN PELTIER WEIWEI ZHANg LEOPOLD VIROT CHRISTIAN LAFFORgUE LUCAS DENIEL DELPHINE MARRIS-MORINI gUY AUBIN FARAH amar DENH TRAN XINgZHAO YAN CALLUM g.LITTLEJOHNS CARLOS ALONSO-RAMOS KE LI DAVID J.THOMSON gRAHAM REED LAURENT VIVIEN University Paris-Saclay CNRSCentre for Nanoscience and Nanotechnology(C2N)Palaiseau 91120France University grenoble Alpes CEALETIGrenoble 38000France Optoelectronics Research Centre Zepler Institute for Photonics and NanoelectronicsFaculty of Engineering and Physical SciencesUniversity of SouthamptonSouthampton SO171BJUK

Silicon-based electro-optic modulators contribute to easing the integration of high-speed and low-power consumption circuits for classical optical communications and data *** the plasma dispersion modulation,an alternative solution in silicon is to exploit the DC Kerr effect,which generates an equivalent linear electro-optical effect enabled by applying a large DC electric *** some theoretical and experimental studies have shown its existence in silicon,limited contributions relative to plasma dispersion have been achieved in high-speed modulation so *** paper presents high-speed optical modulation based on the DC Kerr effect in silicon PIN *** contributions of both plasma dispersion and Kerr effects have been analyzed in different waveguide configurations,and we demonstrated that the Kerr induced modulation is dominant when a high external DC electric field is applied in PIN ***-speed optical modulation response is analyzed,and eye diagrams up to 80 gbit/s in NRZ format are obtained under a *** of 30 *** work paves the way to exploit the Kerr effect to generate high-speed Pockels-like optical modulation.

关键词： waveguide dispersion effect

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OPTIMAL CONTROL OF AN M/g/1 RETRIAL QUEUE WITH VACATIONS

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Journal of Systems Science and Systems Engineering 2008年第4期17卷 487-502页

作者： amar AISSANI University of Science & Technology Houari Boumediene BP 32 El Alia Bab-Ez-Zouar 16111Algeria

In this note, we consider an M/g/1 retrial queue with server vacations, when retrial times, service times and vacation times are arbitrary distributed. The distribution of the number of customers in the system in stationary regime is obtained in terms of generating function. Next, we give heavy traffic approximation of such distribution. We show that the system size can be decomposed into two random variables, one of which corresponds to the system size of the ordinary M/g/1 FIFO queue without vacation. Such a stochastic decomposition property is useful for the computation of performance measures of interest. Finally, we solve simple problems of optimal control of vacation and retrial policies.

关键词： Retrial queues vacation optimal control stochastic decomposition ageing distribution heavy traffic

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Application of hybrid support vector regression artificial bee colony for prediction of MMP in CO2-EOR process

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Petroleum 2020年第4期6卷 415-422页

作者： Menad Nait amar Noureddine Zeraibi Laboratoire génie Physique des Hydrocarbures Faculty of Hydrocarbons and ChemistryUniversity M'hamed Bougara of BoumerdesAvenue de l’Indépendance35000BoumerdesAlgeria

Minimum miscibility pressure(MMP)is a key parameter in the successful design of miscible gases injection such as CO2 flooding for enhanced oil recovery process(EOR).MMP is generally determined through experimental tests such as slim tube and rising bubble apparatus(RBA).As these tests are time-consuming and their cost is very expensive,several correlations have been ***,and although the simplicity of these correlations,they suffer from inaccuracies and bad generalization due to the limitation of their ranges of *** paper aims to establish a global model to predict MMP in both pure and impure CO2-crude oil in EOR process by combining support vector regression(SVR)with artificial bee colony(ABC).ABC is used to find best SVR hyper-parameters.201 data collected from authenticated published literature and covering a wide range of variables are considered to develop SVR-ABC pure/impure CO2-crude oil MMP model with following inputs:reservoir temperature(TR),critical temperature of the injection gas(Tc),molecular weight of pentane plus fraction of crude oil(MWC5+)and the ratio of volatile components to intermediate components in crude oil(xvol/xint).Statistical indicators and graphical error analyses show that SVR-ABC MMP model yields excellent results with a low mean absolute percentage error(3.24%)and root mean square error(0.79)and a high coefficient of determination(0.9868).Furthermore,the results reveal that SVR-ABC outperforms either ordinary SVR with trial and error approach or all existing methods considered in this work in the prediction of pure and impure CO2-crude oil ***,the Leverage approach(Williams plot)is done to investigate the realm of prediction capability of the new model and to detect any probable erroneous data points.

关键词： CO2-EOR process CO2-Crude oil minimum miscibility pressure Support vector regression(SVR) Artificial bee colony(ABC)

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Propagation of surfactant and polymer flow in natural carbonate cores

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Petroleum 2022年第3期8卷 414-423页

作者： Dongqing Cao Jinxun Wang Ming Han amar J.Alshehri Beijing Research Center Aramco AsiaBeijing100102PR China EXPEC Advanced Research Center Saudi AramcoDhahran31311Saudi Arabia

This paper presents an experimental and analytical study of comprehensive effects of surfactant and polymer in aqueous solutions on the propagation in ***-phase flow tests of surfactant,polymer and surfactant-polymer mixture were respectively conducted on natural carbonate core plugs at high temperature and high salinity reservoir *** effect of different factors on chemical propagation was taken into account by use of a convection-dispersion *** dynamic adsorptions of two amphoteric surfactants at 2000 mg/L concentration onto the carbonate rocks were 0.21 and 0.17 mg/g-rock,*** dynamic adsorptions of a sulfonated polymer at 2000 and 5000 mg/L were 0.11 and 0.17 mg/g-rock,***-polymer mixtures in aqueous solutions were coinjected to evaluate their competitive adsorption,showing the surfactant adsorption was reduced by approximately 50%.The dispersion coefficient of the chemicals in the carbonate cores was in the magnitude of 10^(-3) cm^(2)/*** by dispersion and adsorption,chemical concentration reduction occurred obviously during the propagation in carbonate porous *** separation took place in the surfactant-polymer co-injection scheme,which was estimated by modeling as well.

关键词： Natural carbonate core Chemical propagation Polymer Surfactant Competitive adsorption Convention-dispersion model

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An international program on Silk Road Disaster Risk Reduction--a Belt and Road initiative (2016-2020)

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Journal of Mountain Science 2018年第7期15卷 1383-1396页

作者： LEI Yu CUI Peng amar Deep REgMI Virginia MURRAY Alessandro PASUTO giacomo TITTI Muhammad SHAFIQUE Tilak PRIYADARSHANA D.g. Key Laboratory of Mountain Hazards and Earth Surface Processes/Institute of Mountain Hazards and Environment Chinese Academy of Sciences Chengdu 610041 China University of Chinese Academy of Sciences Bering 100049 China CAS Center for Excellence in Tibetan Plateau Earth Sciences Beijing 100101 China Public Health England London 133-155 England UNISDR Scientific and Technical Advisory group Geneva Switzerland Integrated Research on Disaster Risk Scientific Committee Beijing 100094 China Research Institute for C-eo-Hydrological Protection National Research Council 4- 35127 Padova Italy National Center of excellence in geology University of Peshawar Peshawar 25130 Pakistan Internal Quality Assurance Unit &Center for International Affairs University ofRuhuna Matara Sri Lanka

Belt and Road Initiative(BRI) is a Chinese national strategy which calls for cooperative economic, political and cultural exchange at the global level along the ancient Silk Road. The overwhelming natural hazards located along the belt and road bring great challenges to the success of BRI. In this framework, a 5-year international program was launched to address issues related to hazards assessment and disaster risk reduction(DRR). The first workshop of this program was held in Beijing with international experts from over 15 countries. Risk conditions on Belt and Road Countries(BRCs) have been shared and science and technology advancements on DRR have been disseminated during the workshop. Under this program, six task forces have been setup to carry out collaborative research works and three prioritized study areas have been established. This workshop announced the launching of this program which involved partners from different countries including Pakistan, Nepal, Russia, Italy, United Kingdom, Sri Lanka and Tajikistan. The program adopted the objectives of Sendai Framework for Disaster Risk Reduction 2015-2030 and United Nation Sustainable Development goals 2030 and was implemented to assess disaster risk in BRCs and to propose suitable measures for disaster control which can be appropriate both for an individual country and for specific sites. This paper deals with the outcomes of the workshop and points out opportunities for the near future international cooperation on this matter.

关键词： Natural hazards Silk Road Disaster risk reduction Belt and Road Initiative Sendai Framework International collaboration program

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Structural Characterization of Lignins Isolated from Caragana sinica Using FT-IR and NMR Spectroscopy

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光谱学与光谱分析 2011年第9期31卷 2369-2376页

作者： XIAO Ling-ping SHI Zheng-jun XU Feng SUN Run-cang amar K Mohanty College of Material Science and Technology Beijing Forestry University Beijing 100083 China State Key Laboratory of Pulp and Paper Engineering South China University of Technology Guangzhou 510640 China Department of Plant Agriculture Bioproducts Discovery and Development Centre (BDDC)University of Guelph Guelph Ontario N1G 2Wl Canada

In order to efficiently explore and use woody biomass,six lignin fractions were isolated from dewaxed Caragana sinica via successive extraction with organic solvents and alkaline *** lignin structures were characterized by Fourier transform infrared spectroscopy(FT-IR) and 1D and 2D Nuclear Magnetic Resonance(NMR).FT-IR spectra revealed that the "core" of the lignin structure did not significantly change during the treatment under the conditions *** results of 1H and 13C NMR demonstrated that the lignin fraction L2,isolated with 70% ethanol containing 1% NaOH,was mainly composed of β-O-4 ether bonds together with g and S units and trace p-hydroxyphenyl *** on the 2D HSQC NMR spectrum,the ethanol organosolv lignin fraction L1,extracted with 70% ethanol,presents a predominance of β-O-4′ aryl ether linkages(61% of total side chains),and a low abundance of condensed carbon-carbon linked structures(such as ββ′,β-1′,and β-5′) and a lower S/g ***,a small percentage(ca.9%) of the linkage side chain was found to be acylated at the γ-carbon.

关键词： Caragana sinica Lignin Structural characterization FT-IR NMR

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From dredged sediment to supplementary cementitious material:characterization, treatment, and reuse

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International Journal of Sediment Research 2021年第1期36卷 92-109页

作者： Mouhamadou amar Mahfoud Benzerzour Joelle Kleib Nor-Edine Abriak Univ.Lille IMT Lille Douai Univ.Artois Yncrea Hauts-de-France ULR 4515-LGCg E Laboratoire de Génie Civil et Géo-Environnement

Nowadays,the preservation of natural resources,the reuse,and the recycling of waste and by-products in the cement industry are gaining increasing attention in a sustainable development *** this perspective,many studies focus on finding solutions in order to propose environmentally friendly *** the sediments represent a way to preserve the natural resources by their reuse as a secondary raw material in multiple applications(concrete,roads,landscaped mound,etc).However,they commonly contain contaminants,organic matter(5%-30%),high water content(50%-200%),and relatively small particle size(Dmax ≤300 μm).Therefore to improve the mechanical properties of this material as well as its physiochemical ones,specific methods of characterization and appropriate treatment techniques(calcination,chemical treatment,etc.) are *** article presents a bibliographical review of the efficient use of sediments in cementitious *** details experimental tests that must be performed to ensure the durability of sediment-based structure and assess their environmental impact under prescribed conditions.

关键词： Sediment Characterization Calcination Pozzolanicity Durability

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Inflammatory bowel disease:Therapeutic limitations and prospective of the stem cell therapy

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World Journal of Stem Cells 2020年第10期12卷 1050-1066页

作者： Rangnath Mishra Punita Dhawan Anand S Srivastava amar B Singh Institute of Stem Cell Therapy and Research San DiegoCA 92122United States Department of Biochemistry and Molecular Biology University of Nebraska Medical CenterOmahaNE 68118United States Fred and Pamela Buffett Cancer Center OmahaNE 68118United States VA Nebraska-Western Iowa Health Care System OmahaNE 68118United States

Inflammatory bowel disease(IBD),consisting primarily of ulcerative colitis and Crohn’s disease,is a group of debilitating auto-immune disorders,which also increases the risk of colitis-associated ***,due to the chronic nature of the disease and inconsistent treatment outcomes of current anti-IBD drugs(e.g.,approximately 30%non-responders to anti-TNFαagents),and related serious side effects,about half of all IBD patients(in millions)turn to alternative treatment *** this regard,mucosal healing is gaining acceptance as a measure of disease activity in IBD patients as recent studies have correlated the success of mucosal healing with improved ***,despite the increasing clinical realization of the significance of the concept of mucosal healing,its regulation and means of therapeutic targeting remain largely ***,stemcell therapy,which uses hematopoietic stem cells or mesenchymal stem cells,remains a promising *** cells are the pluripotent cells with ability to differentiate into the epithelial and/or immune-modulatory *** overreaching concept is that the stem cells can migrate to the damaged areas of the intestine to provide curative help in the mucosal healing ***,by differentiating into the mature intestinal epithelial cells,the stem cells also help in restoring the barrier integrity of the intestinal lining and hence prevent the immunomodulatory induction,the root cause of the *** this article,we elaborate upon the current status of the clinical management of IBD and potential role of the stem cell therapy in improving IBD therapy and patient’s quality of life.

关键词： Crohn′s disease Ulcerative colitis Mesenchymal stem cells Hematopoietic stem cells Mucosal healing

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Morphological and functional alterations of female reproduction after regular exposure of bamboo shoots of North East India

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Asian pacific Journal of Reproduction 2017年第4期6卷 151-157页

作者： Deotima Sarkar Arijit Chakraborty Dakshayani Mahapatra amar K Chandra Endocrinology and Reproductive Physiology Laboratory Department of PhysiologyUniversity of Calcutta92APC RoadKolkata-700009

Objective:To evaluate the effect of daily consumption of bamboo shoots (BS) on the morphological features and functional status of the female reproductive system in adult with respect to ***: Adult female rats were divided into control and experimental groups of six each. Control group was given normal diet while experimental group was fed BS by 1/3rd replacement of 180 g of their foodi.e.60 g of BS containing 35 g of goitrogens of cyanogenic origin such that each rat likely consumed 6 mg/100 g of body weight per day for a period of 45 d. Morphological features like changes in body weight and organ weight were noted. Key steroidogenic enzyme levels viz?53β hydroxysteroid dehydrogenase (HSD) and 17β HSD along with serum estradiol, estriol and progesterone levels were measured. Estrous cyclicity of the animals monitored regularly followed by histological analysis of thyroid, ovary and uterus at the end of ***:Increase in body weight, thyroid gland weight and thyroid stimulating hormone, decrease in serum triiodothyronine and thyroxine, a decrease in ovarian as well as uterine weight and the activity of steroidogenic enzymes?53β HSD andβ17β HSD along with diminished serum estradiol, estriol and progesterone levels were noted;while histological plates showed prominent degenerative changes in both the ovary and uterus. Estrous cyclicity of the treated animals were irregular and almost stopped at diestrous stage of the cycle in the latter stage of the treatment as compared to ***: Overall results indicates that BS rich in cyanogenic constituents induces biochemical hypothyroidism in the experimental animals that acts in corroboration to cause morphological and functional alteration of reproductive organs indicating its likely impact in fertility on continued use.

关键词： Bamboo shoots Dietary goitrogens Female reproduction Estrogen Steroidogenic enzymes Reproductive disruptor

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