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Green tea polyphenols inhibit testosterone production in rat Leydig cells

Asian Journal of Andrology 2009年第3期11卷 362-370页

作者： Marina S. Figueiroa Juliany S. B. Cesar Vieira Disleide S. Leite ruben C. o. Andrade Filho Fabiano Ferreira Patricia S. Gouveia Daniel P. Udrisar Maria I. Wanderley Department of Physiology and Pharmacology Federal University of Pernambuco 50607-901 Recife PE Brazil

This study investigated the acute effects of green tea extract （GTE） and its polyphenol constituents, （-）-epigallocatechin-3-gallate （EGCG） and （-）-epicatechin （EC）, on basal and stimulated testosterone production by rat Leydig cells in vitro. Leydig cells purified in a Percoll gradient were incubated for 3 h with GTE, EGCG or EC and the testosterone precursor androstenedione, in the presence or absence of either protein kinase A （PKA） or protein kinase C （PKC） activators. The reversibility of the effect was studied by pretreating cells for 15 min with GTE or EGCG, allowing them to recover for 1 h and challenging them for 2 h with human chorionic gonadotropin （hCG）, luteinizing hormone releasing hormone （LHRH）, 22（R）-hydroxycholesterol or androstenedione. GTE and EGCG, but not EC, inhibited both basal and kinase-stimulated testosterone production. Under the pretreatment conditions, the inhibitory effect of the higher concentration of GTE/EGCG on hCG/LHRH-stimulated or 22（R）- hydroxycholesterol-induced testosterone production was maintained, whereas androstenedione-supported testosterone production returned to control levels. At the lower concentration of GTE/EGCG, the inhibitory effect of these polyphenols on 22（R）-hydroxycholesterol-supported testosterone production was reversed. The inhibitory effects of GTE may be explained by the action of its principal component, EGCG, and the presence of a gallate group in its structure seems important for its high efficacy in inhibiting testosterone production. The mechanisms underlying the effects of GTE and EGCG involve the inhibition of the PKA/PKC signalling pathways, as well as the inhibition of P450 side-chain cleavage enzyme and 17β-hydroxysteroid dehydrogenase function.

关键词： green tea polyphenols Leydig cells protein kinase A protein kinase C testosterone

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Machine perfusion and the prevention of ischemic type biliary lesions following liver transplant:What is the evidence?

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World Journal of Gastroenterology 2023年第20期29卷 3066-3083页

作者： Manuel Durán Rafael Calleja Angus Hann George Clarke ruben Ciria Anisa Nutu Rebeca Sanabria-Mateos María Dolores Ayllón Pedro López-Cillero Hynek Mergental Javier Briceño M Thamara P R Perera Department of Liver Transplantation Reina Sofía University HospitalCórdoba 14004Spain The Liver Unit Queen Elizabeth Hospital BirminghamBirmingham B152THUnited Kingdom Centre for Liver and Gastrointestinal Research Institute of Immunology and ImmunotherapyUniversity of BirminghamBirmingham B152THUnited Kingdom

The widespread uptake of different machine perfusion(MP)strategies for liver transplant has been driven by an effort to minimize graft *** to the cholangiocytes during the liver donation,preservation,or early posttransplant period may result in stricturing of the biliary tree and inadequate biliary *** problem continues to trouble clinicians,and may have catastrophic consequences for the graft and *** injury,as a result of compromised hepatic artery flow,is a well-known cause of biliary strictures,sepsis,and graft ***,very similar lesions can appear with a patent hepatic artery and these are known as ischemic type biliary lesions(ITBL)that are attributed to microcirculatory dysfunction rather than main hepatic arterial *** the warm and cold ischemic period duration appear to influence the onset of *** of the commonly used MP techniques deliver oxygen to the graft cells,and therefore may minimize the cholangiocyte injury and subsequently reduce the incidence of *** clinical experience and published evidence grows for these modalities,the impact they have on ITBL rates is important to *** this review,the evidence for the three commonly used MP strategies(abdominal normothermic regional perfusion[A-NRP],hypothermic oxygenated perfusion[HoPE],and normothermic machine perfusion[NMP])for ITBL prevention has been critically *** with ITBL definitions used in trials,coupled with variations in techniques of MP,make interpretation ***,the evidence suggests that both HoPE and A-NRP prevent ITBL in donated after circulatory death grafts compared to cold *** evidence for ITBL prevention in donor after brain death grafts with any MP technique is weak.

关键词： Liver transplant Ischemic type biliary lesions Hypothermic oxygenated machine perfusion Normothermic machine perfusion Abdominal normothermic regional perfusion Donation after circulatory death

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The need to develop tailored tools for improving the quality of thematic bibliometric analyses: Evidence from papers published in Sustainability and Scientometrics

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Journal of Data and Information Science 2023年第4期8卷 10-35页

作者： Alvaro Cabezas-Clavijo Yusnelkis Milanés-Guisado ruben Alba-Ruiz Ángel MDelgado-Vázquez Universidad Internacional de La Rioja(UNIR) Avenida de la Paz137Logroño26006Spain Universidad Pablo de olavide Ctra.de UtreraKm 1Sevilla41013Spain Hospital Universitario Virgen de las Nieves Avenida de las Fuerzas Armadas2Granada 18014Spain

Purpose: The aim of this article is to explore up to seven parameters related to the methodological quality and reproducibility of thematic bibliometric research published in the two most productive journals in bibliometrics, Sustainability(a journal outside the discipline) and Scientometrics, the flagship journal in the ***/methodology/approach: The study identifies the need for developing tailored tools for improving the quality of thematic bibliometric analyses, and presents a framework that can guide the development of such tools. A total of 508 papers are analysed, 77% of Sustainability, and 23% published in Scientometrics, for the 2019-2021 ***: An average of 2.6 shortcomings per paper was found for the whole sample, with an almost identical number of flaws in both journals. Sustainability has more flaws than Scientometrics in four of the seven parameters studied, while Scientometrics has more shortcomings in the remaining three *** limitations: The first limitation of this work is that it is a study of two scientific journals, so the results cannot be directly extrapolated to the set of thematic bibliometric analyses published in journals from all *** implications: We propose the adoption of protocols, guidelines, and other similar tools, adapted to bibliometric practice, which could increase the thoroughness, transparency, and reproducibility of this type of ***/value: These results show considerable room for improvement in terms of the adequate use and breakdown of methodological procedures in thematic bibliometric research, both in journals in the Information Science area and journals outside the discipline.

关键词： Thematic bibliometric analyses Sustainability Scientometrics Reproducibility Methodological quality

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Economically-Driven Partisanship-- official Advertising and Political coverage in Mexico： The Case of Morelia

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Journalism and Mass communication 2013年第1期3卷 14-33页

作者： ruben A. Gonzalez Macias Tecnologico de Monterrey Campus Puebla Mexico

Partisanship and dependence on government support have characterized Mexican media along its history. That is, on the one hand, the journalistic practice has been determined by the alignment towards a political stance. on the other, thanks to the intervention of the state, news outlets---especially newspapers--have survived in an economically difficult environment. Nowadays, the support from the government mainly comes in the form of official advertising, which has become a token to trade revenues for publicity. Therefore, this paper argues that media partisanship in Mexico has shifted from ideological to economic. Based upon a case study conducted in Morelia （the capital city of Michoacan）, this article analyzes the impact of the official advertising on the political information published by the local newspapers.

关键词： Mexican media journalism partisanship coercion official advertising

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Theoretical Investigations of Ti-Based Binary Shape Memory Alloys

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Materials Sciences and Applications 2011年第10期2卷 1355-1366页

作者： Rita John Hannah ruben 不详

The electronic structure and ground state properties of TiX (X = Fe, Ni, Pd, Pt and Cu) type Shape Memory alloys have been calculated using the self consistent Tight- Binding Linear Muffin Tin orbital (TB-LMTo) method. The systematic total energy studies made on TiX alloys in both B2 and (B19/B19’) structures successfully explain the structural stability of these compounds. The equilibrium lattice parameters, bulk moduli (Bo), cohesive energy (Ecoh) and heat of formation (ΔH) are calculated for these systems and compared with the available experimental and other theoretical results. The bonding nature of these TiX alloys is analyzed via the density of states (DoS) histogram.

关键词： Shape Memory Alloys TB-LMTo B2-B19 Phases Structural Parameters

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Dark Fermentative H2 Production from Wastes： Effect of operating conditions

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Journal of Environmental Science and Engineering(A) 2012年第7期1卷 936-950页

作者： ruben Moreno Xiomar Gomez Institute of Natural Resources University of Leon Leon 24071 Spain

Hydrogen （H2） appears as one of the most promising alternative forms of energy supply, as it is non-pollutant and has a high heating value. The production of H2 by non-conventional ways, such as fermentative production, depends on economic factors and the H2 yield achieved in the process. Therefore, this review summarizes the basic aspects of hydrogen production, specifically focusing on the role of the dark fermentation process, as a way to produce this gas by biological means. The different parameters affecting the production of H2 are also discussed. The existence of different hydrogen producing microorganisms with different enzymes causes the necessity to investigate the effect of the conditions under which the process is carried out. Thus, the factors influencing the fermentative process, such as pH, temperature, inoculum pretreatment, hydraulic retention time, hydrogen partial pressure and substrate composition （metal ions, nitrogen source, etc.） are summarized.

关键词： Anaerobic digestion hydrogen economy hydrogenase.

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Strategies to reduce hepatitis C virus recurrence after liver transplantation

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World Journal of Hepatology 2013年第5期5卷 237-250页

作者： ruben Ciria María Pleguezuelo Shirin Elizabeth Khorsandi Diego Davila Abid Suddle Hector Vilca-Melendez Sebastian Rufian Manuel de la Mata Javier Briceo Pedro López Cillero Nigel Heaton Institute of Liver Studies King’s College HospitalLondon SE5 9RSUnited Kingdom Unit of Hepatology and Liver Transplantation University Hospital Reina Sofías/n 1400 CórdobaSpain Unit of Hepatobiliary Surgery and Liver Transplantation University Hospital Reina Sofías/n 1400 CórdobaSpain

Hepatitis C virus (HCV) is a major health problem that leads to chronic hepatitis, cirrhosis and hepatocellular carcinoma, being the most frequent indication for liver transplantation in several countries. Unfortunately, HCV re-infects the liver graft almost invariably following reperfusion, with an accelerated history of recurrence, leading to 10%-30% of patients progressing to cirrhosis within 5 years of transplantation. In this sense, some groups have even advocated for not retransplanting this patients, as lower patient and graftoutcomes have been reported. However, the management of HCV recurrence is being optimized and several strategies to reduce post-transplant recurrence could improve outcomes, decrease the rate of re-transplantation and optimize the use of available grafts. Three moments may be the focus of potential actions in order to decrease the impact of viral recurrence: the pretransplant moment, the transplant environment and the post-transplant management. In the pre-transplant setting, it is not well established if reducing the pre transplant viral load affects the risk for HCV progression after transplant. obviously, antiviral treatment can render the patient HCV RNA negative post transplant but the long-term benefit has not yet been fully established to justify the cost and clinical risk. In the transplant moment, factors as donor age, cold ischemia time, graft steatosis and ischemia/reperfusion injury may lead to a higher and more aggressive viral recurrence. After the transplant, discussion about immunosuppression and the moment to start the treatment (prophylactic, pre-emptive or once-confirmed) together with new antiviral drugs are of interest. This review aims to help clinicians have a global overview of posttransplant HCV recurrence and strategies to reduce its impact on our patients.

关键词： Hepatitis C virus Recurrence Liver Trans- plantation outcomes

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Deepening Democracy

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Beijing Review 2022年第13期65卷 24-25页

作者： ruben Guzzetti Marcelo Rodriguez China Studies Department of the Center for Marxist Studies and Training in Argentina said department of the Center for Marxist Studies and Training in Argentina

The debate about what democracy is crosses political and academic boundaries,extending across certain contexts of *** system,conceived to defend the people’s right to elect and supervise their rulers through mechanisms of direct or indirect participation,is adopted in many Western countries,and in Latin America in particular,the *** is used.

关键词： Latin debate participation

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Critical relative indentation depth in carbon based thin films

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Progress in Natural Science:Materials International 2014年第3期24卷 287-290页

作者： ruben Bartali Alessandro Vaccari Victor Micheli Gloria Gottardi Rajesh Pandiyan Amos collini Paolo Lori Gianni coser Nadhira Laidani Fondazione Bruno Kessler - Ricerca Scientifica e Tecnologica Center for Materials and Microsystems Fondazione Bruno Kessler – Ricerca Scientifica e Tecnologica Center for Materials and Microsystems

The thin film hardness estimation by nanoindentation is influenced by substrate beyond a critical relative indentation depth(CRID). In this study we developed a methodology to identify the CRID in amorphous carbon film. Three types of amorphous carbon film deposited on silicon have been studied. The nanoindentation tests were carried out applying a 0.1–10 mN load range on a Berkovich diamond tip, leading to penetration depth-to-film thickness ratios of 8–100%. The work regained during unloading(We) and the work performed during loading(Wt) was estimated for each indentation. The trend of unload-to-load ratio(We/Wt) data as a function of depth has been studied. We/Wtdepth profiles showed a sigmoid trend and the data were fitted by means of a Hill sigmoid equation. Using Hill sigmoid fit and a simple analytical method it is possible to estimate CRID of carbon based films.

关键词： Nanoindentation Carbon film Critical relative indentation depth We/Wt

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Potential role of lava lizards as pollinators across the Galápagos Islands

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Integrative Zoology 2020年第2期15卷 144-148页

作者： Sandra HERVÍAS-PAREJo Manuel NoGALES Beatriz GUZMÁN María del Mar TRIGo Jens MoLESEN Pablo VARGAS ruben HELENo Anna TRAVESET Global Change Research Group Mediterranean Institute for Advanced StudiesMallorcaBalearic IslandsSpain Island Ecology and Evolution Research Group Institute of Natural Products and AgrobiologyCanary IslandsSpain Royal Botanical Garden of Madrid MadridSpain Department of Plant Biology Málaga UniversityMálagaSpain Department of Bioscience Aarhus UniversityAarhusDenmark Centre for Functional Ecology Department of Life SciencesUniversity of CoimbraCoimbraPortugal

Lizards have been reported as important pollinators on several oceanic *** we evaluate the potential role of Galápagos lava lizards(Microlophus spp.)as pollinators across their *** 3 years,we sampled pollen transport by 9 lava lizard species on the 10 islands where they are present,including 7 single-island ***,only 25 of 296 individuals sampled(8.4%)transported pollen of 10 plant species,the most common being Prosopis juliflora,Exodeconus miersii,Sesuvium *** cordia *** least 8 of these plant species were native,and none were confirmed as introduced to the *** the low overall proportion of individuals carrying pollen,this was observed in 7 of the nine lizard species,and on 8 of the ten main islands(Española,Fernandina,Floreana,Isabela,Marchena,Pinta,Santa Cruz and Santiago),suggesting that this is a widespread *** results reported here support the potential role of lava lizards as pollinators across their radiation,although they may represent a relatively modest contribution when compared with birds and ***,we cannot discard that lizards may be ecologically significant for particular plant species and ecosystems given the specific climatic condition and functional diversity of each island.

关键词： flower visitation Microlophus spp. mutualistic interactions pollination vertebrate radiation

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