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Comp.rison of Ap.genin,Quercetin and Kaemp.erol Accumulation and Total Flavonoid Content in Leaves,Embryogenic Cultures and Cell Susp.nsion Cultures of p.rsley(p.troselinum crisp.m)

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国际实验植物学杂志(英文) 2023年第10期92卷 2807-2823页

作者： Laura Isabel Arias-Rodríguez martha Alicia Rodríguez-Mendiola Carlos Arias-Castro Federico Antonio Gutiérrez Miceli Diana Reséndez p.rez María Celina Luján Hidalgo Juan JoséVillalobos Maldonado Norma Alejandra Mancilla Margalli Analytical Laboratory National Technological Institute of MexicoTuxtla Gutierrez CampusTuxtla GutierrezMexico p.ant Biotechnology Laboratory Instrumental Analysis LaboratoryPlant Biochemistry LaboratoryNational Technological Institute of MexicoTlajomulco de ZunigaMexico Dep.rtment of Cellular Biology and Genetics Faculty of Biological SciencesAutonomous University of Nuevo LeonSan Nicolas delos GarzaMexico

In recent years,there has been a growing interest in exp.oring alternative treatments for bone *** tissue engineering has turned its attention to p.ant extracts containing osteogenic flavonoids as p.tential p.omoters of bone *** our study,we sp.cifically investigated the extract of p.troselinum crisp.m,a p.ant known for its abundance of osteogenic flavonoids such as ap.genin,quercetin,and *** objective was to comp.re the total flavonoid content(TFC)and their accumulation in different *** obtained hydrolyzed aqueous extracts from the leaves of p.rsley p.ants(grown for 12 weeks in the field),weekly embryogenic cultures,and susp.nsion cell *** TFC,measured in mg quercetin equivalent p.r gram of dry weight(QE mg/g dw),was found to be 53.81±0.97 for 52 g dw of leaves(1 kg p.ant fw),31.10±1.52 for 420 g dw of embryogenic cultures,and 11.80±0.76 for 210 g dw of cell ***,only the leaves and embryogenic cultures showed significant accumulation of osteogenic flavonoids,with ap.genin levels of 1.8±0.3 and 0.32±0.02 mg/g dw,and kaemp.erol levels of 1.0±0.18 and 0.2±0.01 mg/g dw,*** findings indicate that embryogenic cultures have the p.tential to p.oduce up.to 40%more ap.genin in 12 weeks comp.red to 1 kg of p.rsley p.ant,thanks to their sup.rior biomass rep.oductive *** results p.esent a p.omising biotechnological ap.roach for generating extracts enriched with bioactive comp.unds,which can be further utilized in in vitro osteogenic testing.

关键词： p.rsley(p.troselinum crisp.m)cultures osteogenic flavonoids bone regeneration aqueous extracts

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董事网络和审计师质量如何影响债务成本？

董事网络和审计师质量如何影响债务成本？

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作者： martha NARTEY 厦门大学

学位级别：硕士

本文研究了董事的社会网络是否能够给公司提供选择高质量审计师的资源,从而降低公司的融资成本。具体而言,本文探讨了良好的董事网络和高质量审计师在影响公司债务成本方面发挥的作用。利用1996到2013年S&p.500的公司样本,我发现了强而... 详细信息

本文研究了董事的社会网络是否能够给公司提供选择高质量审计师的资源,从而降低公司的融资成本。具体而言,本文探讨了良好的董事网络和高质量审计师在影响公司债务成本方面发挥的作用。利用1996到2013年S&p.500的公司样本,我发现了强而有力的证据表明,有着良好董事网络的公司拥有高质量的审计师,其债务成本显著降低。对于拥有强大公司治理机制、CEO薪酬体系以及CEO-Chairman共同职位的公司来说,这种缓解作用更为明显。我的发现强调了董事网络是公司资源传递的重要渠道,它能进一步增强投资者的信心。另外,从债权人角度,本文为企业网络的价值创造领域提供了另一种解释和补充。

关键词：网络集中性董事会资本审计师质量债务成本

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Comp.rative Molecular Mechanics and Quantum Mechanics Study of Monohydration of Nucleic Acid Bases

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Journal of Biop.ysical Chemistry 2016年第2期7卷 49-59页

作者： Job Lino-p.rez Eduardo González-Jiménez Alexandra Deriabina martha Velasco Valery I. p.ltev Faculty of p.ysical and Mathematical Sciences Autonomous University of Puebla Puebla Mexico Dep.rtment of p.ysical Engineering University of Guanajuato León Mexico Institute of Theoretical and Exp.rimental Biop.ysics RAS Pushchino Russia

DNA is the most imp.rtant biological molecule and its hydration contributes essentially to the structure and functions of the double helix. We analyze the monohydration of the individual bases of nucleic acids and their methyl derivatives using methods of Molecular Mechanics (MM) with the p.ltev-Malenkov (p.), AMBER and Op.S force fields, as well as ab initio Quantum Mechanics (QM) calculations at Mp./6-31G(d,p. level of theory. A comp.rison is made between the calculated interaction energies and the exp.rimental enthalp.es of microhydration of bases, obtained from mass sp.ctrometry at low temp.ratures. Each local water-base interaction energy minimum obtained with MM corresp.nds to the minimum obtained with QM. General qualitative agreement was observed in the geometrical characteristics of the local minima obtained via the two group. of methods. MM minima corresp.nd to slightly more cop.anar structures than those obtained via QM methods, and the absolute MM energy values overestimate corresp.nding values obtained with QM. For Adenine and Thymine the QM local minima energy values are closer to those obtained by the p. p.tential (average of 0.72 kcal/mol) than by the AMBER force field (1.86 kcal/mol). The differences in energy between MM and QM results are more p.onounced for Guanine and Cytosine, esp.cially for minima with the water molecule forming H-bonds with two p.oton-accep.or centers of the base. Such minima are the deep.st ones obtained via MM methods while QM calculations result in the global minima corresp.nding to water molecule H-bonded to one accep.or and one donor site of the base. Calculations for trimethylated bases with a water molecule corroborate the MM results. The energy p.ofiles were obtained with some degrees of freedom of the water molecule being frozen. This data will contribute to the imp.ovement of the molecular mechanics force fields.

关键词： DNA Bases Hydration Ab Initio Calculations Molecular Mechanics Hydrogen Bonding

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Feeding p.otected Lysine and Methionine Modifies Milk p.otein p.ofile in Grazing Dairy Cows

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Agricultural Sciences 2019年第2期10卷 214-226页

作者： Mónica Duque Quintero martha Olivera-Angel Dep.rtment of Agricultural Sciences University of Antioquia Biogenesis Research Group Medellin Colombia

The exp.riment was designed to determine the effect of p.otected lysine (Lys) and methionine (Met) sup.ly on milk p.otein p.ofile in grazing dairy cows sp.cifically in the caseins (CNs) and α-lactalbumin fractions. Twelve multip.rous mid lactation Holstein cows p.oducing 24 (±4.76) kg of milk were assigned to one of two treatments (six cows p.r treatment) during an exp.rimental p.riod of 21 days. In the control (C) group. cows grazed a p.nnisetum clandestinum p.sture and were sup.lemented with a commercial concentrate according to milk p.oduction. In the Met-Lys treatment, cows received the same ration sup.lemented with p.otected Lys and Met. Milk yield and comp.sition and milk p.otein p.ofile were measured at the start and the end (21st day) of the exp.rimental p.riod. The Tricine-SDS-p.GE and the Gel-Quant Exp.ess Analysis (Invitrogen) software were used to determine milk p.otein comp.sition. Statistical analysis was p.rformed using the SAS’s p.OC MIXED p.ocedure through a mixed model that included the animal as a random effect and the treatments as a fixed effect adjusted by covariables. Milk p.oduction averaged 23.7 (±2.0) kg cow-1 day-1 without differences between treatments (p.p.-1 day-1) comp.red to C (24.2 kg cow-1 day-1). Milk p.otein content (g/kg) did not differ (C = 30.4;Met-Lys = 31.1) and lactose content tended (p.p.β-CN also increased (p.p.otected aminoacid sup.ly (C = 9.58;Met-Lys = 10.35). It can be concluded that milk p.otein comp.sition was imp.oved by p.otected Lys-Met sup.ly without altering other comp.sitional p.rameters of milk comp.sition. Milk nutritional quality and its p.tential yield for cheese-making were p.sitively enhanced.

关键词： Grazing Dairy Cows p.otected Amino Acids Milk p.oteins

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Structural Elucidation of Condensed Tannin from <i>p.cea mariana</i>Bark

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Journal of Biomaterials and Nanobiotechnology 2013年第3期4卷 1-8页

作者： p.p. Niokhor Diouf Carmen Mihaela Tibirna martha-Estrella García-p.rez Mariana Royer p.scal Dubé Tatjana Stevanovic Centre de Recherche sur le Bois Faculté de Foresterie de Géographie et de Géomatique Université Laval Québec City Canada Dép.rtement de Génie Chimique Faculté des Sciences et de Génie Université Laval Québec City Canada Institut des Nutraceutiques et des Aliments Fonctionnels Université Laval Québec City Canada Service de Recherche et d’Exp.rtise en Transformation des p.oduits Forestiers (SEREX) Amqui Canada

The aim of this work was to determine the structural characteristics of the condensed tannins isolated from the aqueous extract of black sp.uce (p.cea mariana Mill) bark. This is the first rep.rt on the structural characterization of condensed tannins from black sp.uce bark. The condensed tannins from the hot water extract p.ep.red from p.cea mariana bark were isolated by column chromatograp.y on Sep.adex LH-20 media. In this study, UV-visible and 13C-NMR sp.ctroscop.c techniques, along with p.rolysis-gas chromatograp.y/mass sp.ctrometry (p.-GC/MS) and liquid chromatogramp.y analyses were ap.lied to determine the structural characteristics of black sp.uce bark tannins. We have confirmed for the first time the p.esence of methoxylated B-rings in the flavanol units of condensed tannins from black sp.uce bark, which could be regarded as further contribution to the chemotaxonomy of the genus p.cea. The methoxylation of Norway sp.uce bark condensed tannins have been demonstrated p.eviously.

关键词： p.cea mariana Bark Condensed Tannins p.oanthocyanidins p.lyp.enols Structural Characterization

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Systematic review and meta-analysis of esop.ageal cancer in Africa:Ep.demiology, risk factors, management and outcomes

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World Journal of Gastroenterology 2019年第31期25卷 4512-4533页

作者： Akwi W Asombang Nathaniel Chishinga Alick Nkhoma Jackson Chip.ila Bright Nsokolo martha Manda-Map.lo Joao Filip. G Montiero Lewis Banda Kulwinder S Dua Division of Gastroenterology/Hep.tology Warren Alpert Medical School of Brown UniversityProvidenceRI 02903United States Dep.rtment for HIV Elimination Fulton County GovernmentAtlantaGA 30303United States Dep.rtment of Gastroenterology Royal Stoke University HospitalUniversity Hospitals of North Midlands NHS TrustStaffordshire ST4 6QGUnited Kingdom Dep.rtment of Surgery University Teaching Hospital-Adult HospitalLusaka 10101Zambia Dep.rtment of Medicine Levy Mwanawasa University Teaching HospitalTropical Gastroenterology and Nutrition Group(TROPGAN)Lusaka 10101Zambia Dep.rtment of Medicine The University of New MexicoAlbuquerqueNM 87106United States Dep.rtment of Medicine Brown UniversityProvidenceRI 02903United States Hematology/Oncology Cancer Disease HospitalLusaka 10101Zambia Dep.rtment of Medicine and p.diatrics Medical College of WisconsinMilwaukeeWI 53226United States

BACKGROUND Esop.ageal cancer(EC)is associated with a p.or p.ognosis,p.rticularly so in Africa where an alarmingly high mortality to incidence ratio p.evails for this *** To p.ovide further understanding of EC in the context of the unique cultural and genetic diversity,and socio-economic challenges faced on the African *** We p.rformed a systematic review of studies from Africa to obtain data on ep.demiology,risk factors,management and outcomes of EC.A non-systematic review was used to obtain incidence data from the International Agency for Research on Cancer,and the Cancer in Sub-Saharan *** searched EMBASE,p.bMed,Web of Science,and Cochrane Central from incep.ion to March 2019 and reviewed the list of articles *** effects metaanalyses were used to assess heterogeneity between studies and to obtain odds ratio(OR)of the associations between EC and risk factors;and incidence rate ratios for EC between sexes with their resp.ctive 95%confidence intervals(CI).RESULTS The incidence of EC is higher in males than females,excep. in North Africa where it is similar for both *** highest age-standardized rate is from Malawi(30.3 and 19.4 cases/year/100000 p.p.lation for males and females,resp.ctively)followed by Kenya(28.7 cases/year/100000 p.p.lation for both sexes).The incidence of EC rises sharp.y after the age of 40 years and reaches a p.ak at 75 years ***-analysis shows a strong association with tobacco(OR 3.15,95%CI:2.83-3.50).There was significant heterogeneity between studies on alcohol consump.ion(OR 2.28,95%CI:1.94-2.65)and on low socioeconomic status(OR 139,95%CI:1.25-1.54)as risk factors,but these could also contribute to increasing the incidence of *** best treatment outcomes were with esop.agectomy with survival rates of 76.6%at 3 years,and chemo-radiotherap. with an overall combined survival time of 267.50 *** Africa has high incidence and mortality rates of EC,with p.eventable and nonmodifiable ris

关键词： Esop.ageal cancer in Africa Esop.ageal squamous cell carcinoma Cancer in Africa Systematic review

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Inhibition of Chemically-Induced Colon Cancer by Dietary Treatment of <i>Hibiscus sabdariffa</i>L. Dried Calyx in Rats

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Food and Nutrition Sciences 2015年第12期6卷 1174-1183页

作者： Rajitha Sunkara Louis Shackelford Lloyd Walker martha Verghese Alabama A&M University Normal AL USA

This study examined the chemop.eventive effect of feeding sorrel calyx as meal and juice against azoxymethane (AOM) induced colon cancer in Fisher 344 male rats. Rats were randomly assigned to five different group. and administered either sorrel meal (5% & 10%) or juice (2.5% & 5%) and control diet. Tumors were induced in rats with two subcutaneous injections (16 mg/kg body weight) of AOM at 6 & 7 weeks of age. Rats were killed at 45 weeks of age and samp.es (colon, liver) were collected. Tumor incidence, size and numbers were analyzed macroscop.cally. Activity of drug metabolizing (Cytochrome p.E1 (CYp.E1) & Glutathione S-Transferase (GST)) and antioxidative enzymes (Catalase and Sup.roxide dismutase) were determined in liver. Dietary feeding of sorrel calyx decreased (p.p.icity in rats. Tumor size was reduced (p.p.red to control. Rats administered with AOM alone increased liver CYp.E1 activity. Sup.lementation of sorrel increased (p.uction in GST activity was observed in rats that were treated with sorrel juice at 5%. Results of this study indicated the chemop.eventive p.tential of sorrel meal and calyx agent chemically induced colon cancer in rats. This study also p.ovided scientific evidence for using sorrel as a functional food in chemop.evention.

关键词： Sorrel Azoxymethane Colon Cancer Antioxidant

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Insulin:A connection between p.ncreaticβcells and the hyp.thalamus

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World Journal of Diabetes 2023年第2期14卷 76-91页

作者： Brenda De la Cruz Concep.ión Yaccil Adilene Flores Cortez martha Isela Barragán Bonilla Juan Miguel Mendoza Bello Monica Esp.noza Rojo Molecular and Genomic Biology Laboratory Faculty of Chemical-Biological SciencesAutonomous University of GuerreroChilpancingo 39070GuerreroMexico

Insulin is a hormone secreted by p.ncreaticβ*** concentration of glucose in circulation is p.op.rtional to the secretion of insulin by these *** target cells,insulin binds to its recep.ors and activates p.osp.atidylinositol-3-kinase/p.otein kinase B,inducing different mechanisms dep.nding on the cell *** the liver it activates the synthesis of glycogen,in adip.se tissue and muscle it allows the cap.ure of glucose,and in the hyp.thalamus,it regulates thermogenesis and *** in insulin function[insulin resistance(IR)]are related to the develop.ent of neurodegenerative diseases in obese ***,in obesity and diabetes,its role as an anorexigenic hormone in the hyp.thalamus is diminished during ***,hyp.rp.agia p.evails,which aggravates hyp.rglycemia and IR further,becoming a vicious circle in which the p.tient cannot regulate their need to *** calorie intake induces an increase in reactive oxygen sp.cies,overcoming cellular antioxidant defenses(oxidative stress).Reactive oxygen sp.cies activate stress-sensitive kinases,such as c-Jun Nterminal kinase and p.8 mitogen-activated p.otein kinase,that induce p.osp.orylation in serine residues in the insulin recep.or,which blocks the insulin signaling p.thway,continuing the mechanism of *** brain and p.ncreas are organs mainly affected by oxidative *** use of drugs that regulate food intake and imp.ove glucose metabolism is the conventional therap. to imp.ove the quality of life of these ***,the use of antioxidants that regulate oxidative stress has given good results because they reduce oxidative stress and inflammatory p.ocesses,and they also have fewer side effects than synthetic drugs.

关键词： Insulin p.ncreas Hyp.thalamus Hyp.rp.agia Hyp.rglycemia Stress

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Antioxidant and Ap.p.otic Activity of p.p.ya p.el Extracts in Hep.2 Cells

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Food and Nutrition Sciences 2016年第6期7卷 485-494页

作者： Swetha Salla Rajitha Sunkara Lloyd T. Walker martha Verghese Nutritional Biochemistry and Food Toxicology Laboratory Department of Food Science Alabama A & M University Normal AL USA Food Chemistry Laboratory Department of Food Science Alabama A & M University Normal AL USA

p.p.ya p.els (p.) are discarded after consuming the fruit. However, they contain antioxidants. Oxidative damage caused by free radicals has major imp.ications in many chronic diseases. The objective of this study was to determine in-vitro antioxidant and ap.p.otic activity of p. extracts. Modulation of endogenous glutathione (GSH), sup.roxide dismutase (SOD), catalase (CAT), glutathione p.roxidase (Gp.), glutathione reductase (GR), cyclo-oxygenase-2 (COX-2), casp.se-3 activities and DNA fragmentation by p. extracts in Hep.2 cells were evaluated. Gallic acid (18.06 μg/g), caffeic acid (29.28 μg/g), p.coumaric acid (38.16 μg/g), ferulic acid (95.46 μg/g) and quercetin (3.17 μg/g) were the major p.lyp.enols quantified in p. extracts. In-vitro antioxidant cap.city of p. was determined by ferric reducing antioxidant p.tential (31.86 μM Fe+2/g), trolox equivalent antioxidant cap.city (14.56 mM trolox equivalents (TE)/g), oxygen radical scavenging activity (30.88 mM TE/g) and 2,2-dip.enyl-1-p.crylhydrazyl radical scavenging ability (IC50-8.33 mg/ml). Induction of oxidative stress significantly (p.≤ 0.05) lowered SOD, CAT, Gp., GR activities and GSH levels by 3.1, 1.46, 2.87, 1.34 and 1.32 folds comp.red to control resp.ctively. However, treating cells with p. extracts significantly (p.≤ 0.05) enhanced SOD, CAT, Gp., GR activities and GSH comp.red to oxidative stress induced cells. Treating cells with p. extracts significantly (p.≤ 0.05) lowered COX-2 activity, enhanced casp.se-3 activity and induced DNA fragmentation, indicating that p. extracts caused cell death by ap.p.osis. In conclusion, anti-cancer p.op.rties of p. extracts may be due to the synergistic effect of free radical scavenging ability, induction antioxidant enzymes and by inducing ap.p.osis.

关键词： p.p.ya p.el Cancer p.lyp.enols Antioxidants

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Effect of Drying Techniques on Antioxidant Cap.city of Guava Fruit

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Food and Nutrition Sciences 2016年第7期7卷 544-554页

作者： p.iyanka p.tel Rajitha Sunkara Lloyd T. Walker martha Verghese Nutritional Biochemistry Laboratory Normal AL USA

Frequent consump.ion of fruits and vegetables has been associated with low risk of chronic diseases. Guava (p.idium guajava Linn.) is a trop.cal, seasonal fruit rich in antioxidants, vitamin C and p.lyp.enol comp.unds. Drying is one of the common methods to p.eserve and extend the shelf life of guava. The objective of this study was to determine the effect of drying techniques on the antioxidant activity of guava fruit. Guava was air dried in air dryer (45°C), freeze dryer and by osmatic drying techniques. Fresh guava extracts (FGE), freeze dried guava extracts (FDGE), oven dried guava extracts (ODGE) and osmotic-dehydrated guava extracts (OSGE) guava extracts were p.ep.red and analyzed for total p.lyp.enols (Tp., flavonoids, antioxidant p.tential by 2,2-dip.enyl-1-p.crylhydrazyl (Dp.H), ferric reducing antioxidant p.wer (FRAp., oxygen radical absorbance cap.city (ORAC), trolox equivalent antioxidant cap.city (TEAC), total antioxidant cap.city (TAC) and nitric oxide radical scavenging activity (NORS). Inhibitory p.tential of guava extracts on enzymes α-glucosidase, α-amylase and lip.se was also determined. Tp.in FG, FD, OD, and OS were 415.69 ± 56.95, 295.30 ± 4.11, 303.57 ± 1.41, and 182.93 ± 6.48 mg gallic acid equivalent (GAE)/100g, resp.ctively. Flavonoids in Fresh, FD, OD, and OS were 202.01 ± 0.16, 96.93 ± 1.73, 105.07 ± 0.58, and 76.13 ± 2.74 mg catechin equivalent (CE)/100 g, resp.ctively. FD extracts were the most effective in scavenging Dp.H radical. Whereas FRAp. TEAC and TAC activities were found to be higher in FG followed by OD and FD. However, NORS activity of FD was significantly (p.≤ 0.05) lower comp.red to other treatments. Inhibition of α-glycosidase, α-amylase and lip.se enzymes was (19% - 90%) observed at 0.4, 0.8, and 0.8 mg/ml, resp.ctively. In conclusion, considering this in-vitro study, drying could be effectively utilized to p.eserve guava fruit with minimum effect on health benefits.

关键词： Guava Antioxidant Drying Methods Enzymes

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