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Mo_(2)P Monolayer as a Superior Electrocatalyst for Urea Synthesis from Nitrogen and Carbon Dioxide Fixation:A Computational Study

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Energy & Environmental Materials 2024年第1期7卷 207-214页

作者： Dongxu Jiao Zhongxu Wang Yuejie Liu Qinghai Cai Jingxiang Zhao carlos r.cabrera Zhongfang Chen College of Chemistry and Chemical Engineering and Key Laboratory of Photonic and Electronic Bandgap Materials Ministry of EducationHarbin Normal UniversityHarbin 150025China Modern Experiment Center Harbin Normal UniversityHarbin 150025China Heilongjiang Province Collaborative Innovation Center of Cold region Ecological Safety Harbin 150025China Department of Chemistry and Biochemistry The University of Texas at El PasoEl Paso TX 79968USA Department of Chemistry University of Puerto RicoRio Piedras CampusSan JuanPuerto Rico 00931USA

Urea synthesis through the simultaneous electrocatalytic reduction of N_(2)and CO_(2)molecules under ambient conditions holds great promises as a sustainable alternative to its industrial production,in which the development of stable,highly efficient,and highly selective catalysts to boost the chemisorption,activation,and coupling of inert N_(2)and CO_(2)molecules remains rather ***,by means of density functional theory computations,we proposed a new class of two-dimensional nanomaterials,namely,transition-metal phosphide monolayers(TM_(2)P,TM=Ti,Fe,Zr,Mo,and W),as the potential electrocatalysts for urea *** results showed that these TM_(2)P materials exhibit outstanding stability and excellent metallic ***,the Mo_(2)P monolayer was screened out as the best catalyst for urea synthesis due to its small kinetic energy barrier(0.35 eV)for C-N coupling,low limiting potential(-0.39 V),and significant suppressing effects on the competing side *** outstanding catalytic activity of the Mo_(2)P monolayer can be ascribed to its optimal adsorption strength with the key^(*)NCON species due to its moderate positive charges on the Mo active *** findings not only propose a novel catalyst with high-efficiency and high-selectivity for urea production but also further widen the potential applications of metal phosphides in electrocatalysis.

关键词： C-N coupling density functional theory Mo_(2)P monolayer urea synthesis

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Single-atom catalysts with anionic metal centers: Promising electrocatalysts for the oxygen reduction reaction and beyond

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Journal of Energy Chemistry 2021年第12期30卷 285-293,I0006页

作者： Jinxing Gu Yinghe Zhao Shiru Lin Jingsong Huang carlos r.cabrera Bobby G.Sumpter Zhongfang Chen Department of Chemistry University of Puerto Rico.Rio Piedras Campus.San Juan.Puerto Rico 00931USA Center for Nanophase Materials Sciences Oak Ridge National LaboratoryOak RidgeTennessee 37831USA Department of Chemistry and Biochemistry The University of Texas at El PasoEl PasoTexas 79968USA

Ongoing efforts to develop single-atom catalysts(SACs) for the oxygen reduction reaction(Orr) typically focus on SACs with cationic metal centers,while SACs with anionic metal centers(anionic SACs) have been generally ***,anionic SACs may offer excellent active sites for Orr,since anionic metal centers could facilitate the activation of O_(2) by back donating electrons to the antibonding orbitals of O_(2).In this work,we propose a simple guideline for designing anionic SACs:the metal centers should have larger electronegativity than the surrounding atoms in the substrate on which the metal atoms are *** means of density functional theory(DFT) simulations,we identified 13 anionic metal centers(Co,Ni,Cu,ru,rh,Pd,Ag,re,Os,Ir,Pt,Au,and Hg) dispersed on pristine or defective antimonene substrates as new anionic SACs,among which anionic Au and Co metal centers exhibit limiting potentials comparable to,or even better than,conventional Pt-based catalysts towards *** also found that anionic Os and re metal centers on the defective antimonene can electrochemically catalyze the nitrogen reduction reaction(Nrr) with a limiting potential close to that of stepped ru(0001).Overall,our work shows promise towards the rational design of anionic SACs and their utility for applications as electrocatalysts for Orr and other important electrochemical reactions.

关键词： Single-atom catalysts Anionic metal centers Antimonene Oxygen reduction reaction Nitrogen reduction reaction

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Vulcan/Pt/Ce Catalysts Prepared by Impregnation Using EDTA for Direct Methanol Fuel Cell,Direct Ethanol Fuel Cell,and Polymer Electrolyte Membrane Fuel Cell

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Smart Grid and renewable Energy 2013年第7期4卷 1-9页

作者： rolando Guzmán-Blas Christian L.Menéndez carlos A.Vélez Estevao rosim Fachini Aaron Johnston-Peck Sanjaya D.Senanayake Dario Stacchiola Kotaro Sasaki carlos r.cabrera NASA-University research Centers for Advanced Nanoscale Materials Department of Chemistry and PhysicsUniversity of Puerto RicoRio Piedras CampusSan JuanUSA Chemistry Graduate Program University of Puerto RicoRio Piedras CampusSan JuanUSA General Studies College Physical Sciences DepartmentUniversity of Puerto RicoRio Piedras CampusSan JuanUSA Center for Functional Nanomaterials Brookhaven National LaboratoryUptonUSA Chemistry Department Brookhaven National LaboratoryUptonUSA

A wet chemistry synthesis of Pt-Ce doped catalysts on carbon Vulcan support using an impregnation method with EDTA is presented. The composite catalyst was characterized by XrD, XPS and TEM. The catalytic activity of the prepared material was tested in a direct fuel cell using methanol, ethanol and hydrogen as fuels. The polarization and power curves showed that the Vulcan/Pt/Ce(III) doped catalysts improved the performance of the fuel cells when compared with Vulcan-Pt anode materials.

关键词： Cerium Fuel Cell Pt Methanol Ethanol Hydrogen

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A computer vision system for early detection of anthracnose in sugar mango(Mangifera indica)based on UV-A illumination

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Information Processing in Agriculture 2023年第2期10卷 204-215页

作者： Leonardo ramırez Alberto carlos Eduardo cabrera Ardila Flavio Augusto Prieto Ortiz Facultad de Ingenierı´a Universidad Nacional de ColombiaBogota´D.C.111321Colombia

The present work describes the development of a computer vision system for the early detection of anthracnose in sugar mango based on Ultraviolet A illumination(UV-A).Anthracnose,a disease caused by the fungus Colletotrichum sp,is commonly found in the fruit of sugar mango(Mangifera indica).It manifests as surface defects including black spots and is responsible for reducing the quality of the ***,it decreases its commercial *** more detail,this study poses a system that begins with image acquisition under white and ultraviolet ***,it proposes to analyze the red,Green and Blue color information(r,G,B)of the pixels under two types of illumination,using four different methods:rGB-threshold,rGB-Linear Discriminant Analysis(rGBLDA),UV-LDA,and *** analysis produces an early semantic segmentation of healthy and diseased areas of the mango *** results showed that the combination of the linear discriminant analysis(LDA)and UV-A light(called UV-LDA method)in sugar mango images allows early detection of ***,this method achieves the identification of the disease one day earlier than by an expert with respect to the scale of anthracnose severity implemented in this work.

关键词： Sugar mango Anthracnose LDA UV-A light Grading Image processing

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The cold-induced factor CBF3 mediates root stem cell activity,regeneration,and developmental responses to cold

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Plant Communications 2023年第6期4卷 197-211页

作者： Pablo Perez-Garcia Ornella Pucciariello Alvaro Sanchez-Corrionero Javier.cabrera Cristina del Barrio Juan carlos del Pozo Mariano Perales Krzysztof Wabnik Miguel A.Moreno-risueno Centro de Biotecnologíay Genómica de Plantas(Universidad Politécnica de Madrid(UPM)–Instituto Nacional de Investigacióny Tecnología Agraria y Alimentaria–CSIC(INIA-CSIC)) MadridSpain

Plant growth and development involve the specification and regeneration of stem cell niches(SCNs).Although plants are exposed to disparate environmental conditions,how environmental cues affect developmental programs and stem cells is not well *** stem cells are accommodated in meristems in SCNs around the quiescent center(QC),which maintains their *** a combination of genetics and confocal microscopy to trace morphological defects and correlate them with changes in gene expression and protein levels,we show that the cold-induced transcription factor(TF)C-rEPEAT BINDING FACTOr 3(CBF3),which has previously been associated with cold acclimation,regulates root development,stem cell activity,and ***3 is integrated into the SHOrT-rOOT(SHr)regulatory network,forming a feedback loop that maintains SHr ***3 is primarily expressed in the root endodermis,whereas the CBF3 protein is localized to other meristematic tissues,including root *** of cbf3-1 using a wild-type CBF3 gene and a CBF3 fusion with reduced mobility show that CBF3 movement capacity is required for SCN patterning and regulates root ***,cold induces CBF3,affecting QC ***,exposure to moderate cold around 10℃–12℃promotes root regeneration and QC respecification in a CBF3-dependent manner during the recuperation *** contrast,CBF3 does not appear to regulate stem cell survival,which has been associated with recuperation from more acute cold(-4℃).We propose a role for CBF3 in mediating the molecular interrelationships among the cold response,stem cell activity,and development.

关键词： stem cells regeneration organ patterning protein movement cell fate low temperature

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Chronic hepatitis C in hemodialysis patients:Prevalence and liver fibrosis impact in the National Center for renal Health in Peru

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iLIVEr 2022年第3期1卷 141-144页

作者： P.Martin Padilla-Machaca Eduardo Luna-Victoria Ada cabrera Juan-carlos Gómez-De la Torre rocio Galloso Pedro Montes Guillermo Almenara National Hospital EsSaludLimaPerú National University of San Marcos LimaPerú National renal Health Center EsSaludLimaPerú Laboratorio Clínico roe LimaPerú Asociacion Peruana para el Estudio del Hígado(APEH) LimaPerú

Background:Hepatitis C(HCV)remains a serious public health problem in high-risk persons such as patients on chronic *** aimed to estimate the serological prevalence of HCV,the HCV viral load and genotype,and liver fibrosis stage among patients on chronic hemodialysis at the National renal Health Center in Lima,***:From June 2019 to March 2021,all patients who received chronic hemodialysis were invited to *** who provided written informed consent were *** with HCV-positive serology underwent determination of HCV viral *** from subjects with detectable viral load,underwent determination of HCV ***,HCV infected subjects underwent determination of liver fibrosis using transitional elastography(Fibroscan 402):Metavir score:F0-F1:2.5-7.5 kPa,F2:7.6-9.5 Kpa,F3:9.6-12 Kpa,F4(Cirrhosis):12.1-75 ***:Of the 303 subjects invited to participate,174(57.4%)subjects gave their written *** age was 52 years(range 22-91)and 116(66.6%)were *** serology was positive in 35.1%of patients(61/174);however,the prevalence of positive serology with detectable viral load was 20.11%(35/174).Genotype 1a was the most prevalent(85%).The majority(83.6%)of subjects with detectable viral load had values lower than 800.000 IU/***-nine of those 35 subjects underwent elastography evaluation,and 13(44.8%)of them were found to have stage F2-F4 ***:The prevalence of HCV at the largest reference center for hemodialysis in Lima remains high,with GT1a predominance,viral load usually below 800,000 IU/mL and significant liver fibrosis.

关键词： Hepatitis C Hemodialysis Liver fibrosis HCV genotype

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Arc Stability Characterization of Double Coated Electrodes for Hardfacing

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Journal of Mechanical Engineering research 2021年第1期4卷 22-28页

作者： Odonel Gonzalez-cabrera carlos r.Gomez-Perez HectorA.Kairus-Hernandez-Diaz Felix A.Diaz-rosell Villa Clara Information and Technological Management Center.Marta Abreu#55 entre Zayas y Villuendas.Santa Clara.Villa Clara Weldingresearch Center.Central University“Marta Abreu”of Las Villas.Carretera a Camajuaní km 5½.Santa Clara.Villa Clara Electrical Engineering.Central University“Marta Abreu”of Las Villas.Carretera a Camajuaní km 5½.Santa Clara.Villa Clara Physics Mathematics and Computing.Central University“Marta Abreu”of Las Villas.Carretera a Camajuaníkm 5½.Santa Clara.Villa Clara

The aim of this work is to establish the influence of the relative position of the alloy charge C-Cr-Mn in the structure of the coating of rutile electrodes for hardfacing,on the operational behavior(arc stability).For this,three variants of electrodes with similar chemical composition are elaborated in the metallic core and the coating,differentiating only in the relative position that occupies the alloy charge(C-Cr-Mn)in the structure of the coating:internal,external and *** the development of the research,a completely random design is *** operative characterization of the electrodes is performed in terms of the arc *** conclusion,it can be seen that the position of the alloy load influences the operation behavior(stability of the arc).The variant of internal alloy charge in the coating presents the better arc stability performance.

关键词： Arc stability Welding electrode Hardfacing Position of alloy charge

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Six forests in one:Tree species diversity in the Bosque Protector Chongón Colonche,a lowland mountain range in coastal Ecuadorian

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Forest Ecosystems 2022年第6期9卷 725-733页

作者： Oswaldo Jadan David ADonoso Edwin Ponce-ramírez Franz Pucha-Cofrep Omar.cabrera Facultad de Ciencias Agropecuarias Universidad de Cuenca12 de Octubre y Diego de TapiaCuenca010107Ecuador Programa de Doctorado en Conservacion de recursos Naturales Escuela Internacional de DoctoradoUniversidad Rey Juan CarlosMostolesMadridES-28933Spain Departamento de Biología Escuela Politecnica NacionalLadron de Guevara E11⋅253Quito170525Ecuador Geoforest S.A 12 de febrero y Av.Franklin VegaMacas140150Ecuador Grupo de Investigacion Hidrología y Climatología Universidad Tecnica Particular de LojaSan Cayetano Alto S/NLoja110101Ecuador Brandenburg University of Technology(BTU)Cottbus-Senftenberg 03044CottbusGermany Departamento de Ciencias Biologicas y Agropecuarias Universidad Tecnica Particular de LojaSan Cayetano Alto S/NLoja110101Ecuador

Tropical mountain ranges shape the structure of tree communities and promote highly diverse natural ***“Bosque Protector Chong on-Colonche”(BPCC),an 86,000-ha mountain formation situated on the coast of Ecuador,is biogeographically important for the region by connecting floristic elements of the wet Choco and the dry Tumbesian *** understanding of the factors that model tree and palm diversity and distribution in this mountain range are *** measured and identified all trees and palms(DBH≥10 cm)in 289 plots of0.2 ha,distributed throughout *** used generalized linear models to explain the relationship between forest diversity and structure and climatic variables(temperature,rain,aridity),and *** then used cluster and non-metric multidimensional scale(NMDS)analyses to search for distinct forest communities within the *** partition(varpart)was used to determine which predictor variables best explained these distinct forest communities.A species indicator analysis identified the species most likely to define these distinct forest ***,we carried out a niche modeling approach to identify the potential distribution of these forest communities within *** total,we identified 220 tree and palm species in our *** average number of species per plot was 17.8±5.8,ranging from 3 to 40 *** methods sorted the 289study plots into six different forest communities,three communities in the dry forest and three in the semi-humid Garúa *** and temperature,but not altitude or aridity,explained floristic *** results emphasize the high but little cataloged diversity in the lowland mountain rainforests of coastal Ecuador.

关键词： Chongón-Colonche Climatic variables Dry forest Forest communities Garúa forest

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Attenuation of dextran sodium sulphate induced colitis in matrix metalloproteinase-9 deficient mice

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World Journal of Gastroenterology 2006年第40期12卷 6464-6472页

作者： Alfredo Santana carlos Medina Maria Cristina Paz-cabrera Federico Díaz-Gonzalez Esther Farré Antonio Salas Marek W radomski Enrique Quintero Gastroenterology Department and research Unit Hospital Universitario de Canarias Tenerife Spain reumathology Department Hospital Universitario de Canrias Tenerife Spain Pathology Department Hospital Mutua de Terrassa Barcelona Spain Institute of Molecular Medicine University of Texas Houston-Texas United States

AIM: To study whether matrix metalloproteinase-9 (MMP-9) is a key factor in epithelial damage in the dextran sodium sulphate (DSS) model of colitis in ***: MMP-9-deficient and wild-type (wt) mice were given 5% DSS in drinking water for 5 d followed by recovery up to 7 d. On d 5 and 12 after induction of colitis, gelatinases, MMP-2 and MMP-9, were measured in homogenates of colonic tissue by zymography and Western blot, whereas tissue inhibitor of metalloproteinases (TIMPs) were measured by reverse zymography. The gelatinolytic activity was also determined in supernatants of polymorphonuclear leukocytes (PMN) isolated from mice blood. Moreover, intestinal epithelial cells were stimulated with TNF-α to study whether these cells were able to produce MMPs. Finally, colonic mucosal lesions were measured by microscopic examination. rESULTS: On d 5 of colitis, the activity of MMP-9 was increased in homogenates of colonic tissues (0.24 ± 0.1 vs 21.3 ± 6.4, P rom peripheral blood in wt (0.5 ± 0.1 vs 10.4 ± 0.7, P regulated by TNF-α in epithelial intestinal cells (2.5 ± 0.5 vs 14.7 ± 3.0, P rease of TIMP-1 activity, the MMP-9/TIMP-1 balance remained elevated. Finally, in the MMP-9-deficient colitic mice both the extent and severity of intestinal epithelialinjury were significantly attenuated when compared with wt mice. CONCLUSION: We conclude that DSS induced colitis is markedly attenuated in animals lacking MMP-9. This suggests that intestinal injury induced by DSS is modu-lated by MMP-9 and that inhibition of this gelatinase may reduce inflammation.

关键词： Matrix metalloproteinases MMP-9-deficient Dextran sodium sulphate Inflammatory bowel disease Experimental colitis

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Darunavir resistance in HIV Infecting Protease Inhibitor-Experienced Mexican Patients

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World Journal of AIDS 2013年第3期3卷 280-286页

作者： carlos AAgudelo Luis ESoto-ramirez Abraham Katime-Zuniga Lorena cabrera-ruiz Hugo Lara-Sanchez Juan JCalva Department of Infectious Diseases “Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran”Mexico CityMexico Department of Infectious Diseases Hospital Medica Sur and GUIAR GroupMexico CityMexico The Clinical Epidemiology Unit “Instituto Nacional de Ciencias Medicas y Nutricion Salvador Zubiran”Mexico CityMexico.

Background: Darunavir (DrV) is a useful antiretroviral treatment in the salvage therapy of multiclass-resistant HIV-infected patients. This study’s aim was to determine the frequency and risk factors for DrV resistance-associated mutations (DrV-rAM) among DrV-naive Mexican patients with virologic failure after extensive antiretroviral treatment and exposure to at least one protease inhibitor (PI). Methods: HIV-infected patients with a history of at least 2 failed regimes were included and their clinical histories and genotype resistance tests were analyzed. Major PI resistance-associated mutations (PI-rAM), DrV-rAM and resistance to DrV were defined according to the IAS-USA criteria. Previous exposure to PI was compared between patients with DrV-resistant HIV and DrV-susceptible HIV-infected controls. results: The median number of major PI-rAM was 2 (IQr = 0?- 3). In 54.7% (95% CI = 50.0% - 59.4%) of 631 subjects, no DrV-rAM were found on viral genotyping and 6.7% (95% CI = 4.8% - 8.6%) had 3 or more DrV-rAM. The two most frequently found DrV-rAM were in codons I84V (in 22.7% of cases) and L33F (in 20% of cases) in the viral protease gene. The number of major PI-rAM (as a surrogate marker of duration and number of PI used) and previous exposure to (fos) amprenavir or tipranavir were independently associated with DrV-resistant HIV infection. Conclusions: In this Mexican population, despite a high prior PI exposure, HIV-DrV resistance rate is relatively low and successful viral control with DrV-containing combined salvage therapy is expected in most patients.

关键词： Darunavir resistance risk Factors Prevalence Mexico

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