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Nonlinear criterion for strength mobilization in brittle failure of rock and its extension to the tunnel scale

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International journal of Mining Science and Technology 2022年第4期32卷 685-705页

作者： Rodolfo cabezas javier Vallejos Faculty of Engineering and Technology Universidad San SebastianSantiagoChile Advanced Mining Technology Center Universidad de ChileSantiagoChile Department of Mining Engineering Universidad de ChileSantiagoChile

As underground excavations are getting deeper and field stresses increase, the behavior of intact rock blocks plays an increasingly important role in understanding and estimating the overall rock mass strength. To model the brittle behavior of intact rock blocks, the stress–strain curve is usually idealized considering a linear strength mobilization approach(cohesion-weakening-friction-strengthening, CWFS),however, it is well recognized that rock presents a nonlinear behavior in terms of the confining *** study extends the strength mobilization in brittle failure of rock using nonlinear criteria. To determine the model parameters, a standard statistical method that uses the complete laboratory stress–strain curves of the intact rock is employed. Several hypotheses of linear and nonlinear models are statistically compared for different types of rock and confining stress levels. Results demonstrate that the best approach to model the brittle failure of rock is to consider a nonlinear strength envelope, such as the Hoek-Brown criterion assuming a residual uniaxial compressive strength different from zero and a mi parameter that increases, both with simultaneous mobilization. This model helps to recreate highconfining conditions and a more realistic transition between peak and post-peak strength. The obtained parameters are discussed and compared with literature values to verify the validity and to develop guidelines for the estimation of parameters, providing an objective mobilization criterion. Finally, the nonlinear model was applied to a finite element code and extended to a tunnel scale in the brittle rock under high-stress conditions. A reasonable fit between the simulations and the in-situ overbreak measurements was found.

关键词： Nonlinear strength Strength mobilization Brittle failure Intact rock Scaling

South Asian dairy smallholders: A scoping review of practices and zoonoses

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Asian Pacific journal of Tropical Medicine 2023年第10期16卷 446-452页

作者： Emily Schembri Angus j D Campbell juan Pablo villanueva-cabezas Melbourne School of Population and Global Health The University of MelbourneVictoriaAustralia The Nossal Institute for Global Health The University of MelbourneVictoriaAustralia The Peter Doherty Institute for Infection and Immunity The University of Melbourne and the Royal Melbourne HospitalVictoriaAustralia

Objective: To identify and discuss on-farm management practices linked to bacterial zoonosis risk in smallholder dairy farmers in South Asia. Methods: This scoping review was conducted as per the PRISMA-ScR guidelines. Five hundred and two publications were retrieved from five online databases using a comprehensive search strategy. Studies were selected if they discussed a farm management practice which impacted human health within a South Asian country. Results: Twenty-two studies were included. Seven management practices relevant to farmers, livestock and their shared environment were identified including raw milk consumption, farm hygiene management, personal protective equipment uses, animal vaccination, cleaning udders, hand washing and disposal of afterbirth materials. Preventive practices were found to be utilized at lower frequencies compared to risk increasing practices. Awareness of bacterial zoonoses is particularly low within the region. Conclusions: Based on the results of this review, it was determined that improving farmer awareness of bacterial zoonotic diseases may favor several of the presented leverage points within the South Asian smallholder dairy system. Relying on formal school education to improve this awareness may not solve this problem, instead, more focus on accessible and affordable zoonoses education and farming programs is required.

关键词： Management practices Zoonoses Dairy Smallholder system

Constrained sintering and wear properties of Cu-WC composite coatings

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Transactions of Nonferrous Metals Society of China 2017年第10期27卷 2214-2224页

作者： j.L.cabezas-villa L.OLMOS H.j.VERGARA-HERNáNDEZ O.jIMéNEZ P.GARNICA D.BOUVARD M.FLORES División de Estudios de Posgrado e Investigación TecNM/Instituto Tecnológico de MoreliaAv. Tecnológico #1500 Colonia Lomas de Santiaguito Morelia Michoacán C. P. 58120 México INICIT Universidad Michoacana de San Nicolás de HidalgoFco. J. Mujica S/N Morelia Michoacán C. P. 58060 México Universidad de Guadalajara Departamento de Ingeniería de ProyectosJosé Guadalupe Zuno # 48 Los Belenes Zapopan Jalisco C. P. 45100 México Univ. Grenoble Alpes CNRS SIMaP 38000 Grenoble France

Coatings of metal matrix composites(Cu?WC)were fabricated by solid-state *** reinforcing particles indifferent quantities from5%up to30%(volume fraction)were mixed with Cu *** mixing,the powders were poured ontothe surface of copper *** was carried out at1000°C under a reducing atmosphere in a vertical *** was affected by both rigid substrates and WC particles which retarded the radial and axial densification of ***,the coatings were strongly attached to the substrate,and WC particles were randomly distributed within the *** addition ofthe reinforcing particles enhanced the microhardness and reduced the volume loss in wear tests to1/17compared to the *** predominant wear mechanism was identified as abrasion at a load of5N.20%WC(volume fraction)reinforcingparticles led to the maximum values of properties for the composite coating.

关键词： constrained sintering dilatometry dry sliding wear microhardness metal matrix composites coating

Early transmission dynamics of COVID-19 in a southern hemisphere setting:Lima-Peru:February 29^(th)-March 30^(th),2020

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Infectious Disease Modelling 2020年第1期5卷 338-345页

作者： César V.Munayco Amna Tariq Richard Rothenberg Gabriela G.Soto-cabezas Mary F.Reyes Andree Valle Leonardo Rojas-Mezarina César cabezas Manuel Loayza Gerardo Chowell 无 Centro Nacional de Epidemiología Prevencion y Control de EnfermedadesPeruvian Ministry of HealthLimaPeru Department of Population Health Sciences School of Public HealthGeorgia State UniversityAtlantaGAUSA Instituto Nacional de Salud Peruvian Ministry of HealthLimaPeru Peru COVID-19 working group

The COVID-19 pandemic that emerged in Wuhan China has generated substantial morbidity and mortality impact around the world during the last four *** daily trend in reported cases has been rapidly rising in Latin America since March 2020 with the great majority of the cases reported in Brazil followed by Peru as of April 15th,*** Peru implemented a range of social distancing measures soon after the confirmation of its first case on March 6th,2020,the daily number of new COVID-19 cases continues to accumulate in this *** assessed the early COVID-19 transmission dynamics and the effect of social distancing interventions in Lima,*** estimated the reproduction number,R,during the early transmission phase in Lima from the daily series of imported and autochthonous cases by the date of symptoms onset as of March 30th,*** also assessed the effect of social distancing interventions in Lima by generating short-term forecasts grounded on the early transmission dynamics before interventions were put in *** to the implementation of the social distancing measures in Lima,the local incidence curve by the date of symptoms onset displays near exponential growth dynamics with the mean scaling of growth parameter,p,estimated at 0.96(95%CI:0.87,1.0)and the reproduction number at 2.3(95%CI:2.0,2.5).Our analysis indicates that school closures and other social distancing interventions have helped slow down the spread of the novel coronavirus,with the nearly exponential growth trend shifting to an approximately linear growth trend soon after the broad scale social distancing interventions were put in place by the *** the interventions appear to have slowed the transmission rate in Lima,the number of new COVID-19 cases continue to accumulate,highlighting the need to strengthen social distancing and active case finding efforts to mitigate disease transmission in the region.

关键词： COVID-19 SARS-CoV-2 Transmission potential Short-term forecast Reproduction number Generalized growth model

Geochemical elements in suspended particulate matter of Ensenada de La Paz Lagoon,Baja California Peninsula,Mexico:Sources,distribution,mass balance and ecotoxicological risks

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journal of Environmental Sciences 2024年第2期136卷 422-436页

作者： Sandra Soledad Morales-García Pilar de Acacia Pérez-Escamilla Suresh Babu Sujitha Pichaimani Godwyn-Paulson Andrés Felipe Zuniga-cabezas Muthuswamy Ponniah jonathan Instituto Politécnico Nacional(IPN) Centro Mexicano para la Producción más Limpia(CMPL)Av.Acueducto s/nCol.Barrio la Laguna TicománDel Gustavo A.MaderoC.P.07340Ciudad de MéxicoMexico Instituto Politécnico Nacional(IPN) Escuela Superior de Ingeniería y Arquitectura(ESIA)Unidad Ticomán***án 600Delg.Gustavo A.MaderoC.P.07340Ciudad de México(CDMX)Mexico Instituto Politécnico Nacional(IPN) Centro Interdisciplinario de Investigaciones y Estudios sobre Medio Ambiente y Desarrollo(CIIEMAD)Calle 30 de Junio de 1520Barrio la Laguna TicománDel.Gustavo A.MaderoC.P.07340Ciudad de MéxicoMéxico

The present study aimed to evaluate multi-element concentrations(Al,As,Ca,Cd,Co,Cr,Cu,Fe,Mg,Mn,Mo,Ni,Pb,Sr)in suspended particulate material(SPM)collected from Ensenada de La Paz(ELP)lagoon,Baja California Sur,Mexico in two different periods(September and May)to comprehend their origin,geochemical behavior,mass transfer and associated ecotoxicological *** 24 hr variation coefficient of volumetric SPM levels were found to be 51.7%in September and 40.5%in May,signifying the effects of oceanic *** calculated enrichment factor(EF)values for all the studied elements were of higher magnitude because of the high surface area and oxide nature of SPM,and in this study,Mo had the highest EF of 46.77 probably due to its origin from continental *** the ecotoxicological perspective,the integrated toxic risk index revealed low toxic risk to the benthic ***,the mean-ERM-Quotient calculated using the particulate concentrations of As,Cd,Cr,Cu,Ni,Pb indicated 9%probability of toxicity to *** comprehensive geochemical and ecotoxicological assessment of particulate metal concentrations in the ELP lagoon signify low to moderate contamination.

关键词： Suspended particulate material Heavy metals Risk assessment Mass transfer Ensenada de La Paz

Lipase-catalyzed synthesis of fructosyl myristic acid esters as biosurfactants in a low solvent media: Optimization of the bioconversion

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Food Bioscience 2022年第6期50卷 492-501页

作者： juan Tamayo cabezas Amanda Waglay Salwa Karboune Department of Food Science and Agricultural Chemistry McGill University21 111 LakeshoreSte.Anne de BellevueQuebecH9X 3V9Canada

Lipase-catalyzed synthesis of fructosyl myristic acid esters as natural food biosurfactants in low solvent reaction media was investigated. The effect of chain length of fructose-based glycosides as acyl acceptors was found to be inversely proportional to the bioconversion yield. The application of molecular sieves proved unsuccessful in low-solvent media due to their saturation and mass transfer limitations. The substitution of low-solvent myristic acid reaction media with 5% oleic acid led to similar bioconversion yield than that achieved without oleic acid, while no solidification of the reaction media was observed. Response surface methodology using a 3-factor and 5-level central composite design was used to achieve a compromise between mass transfer limitations and catalytic activity of lipase in low-solvent myristic acid reaction media enriched with oleic acid. Modeling found reduced quadratic models accurately described the yield and productivity of the reaction. Maximum bioconversion yield (22%) was achieved using 0.2 mol/L of fructose and 5% (w/v) of Lipozyme® RM IM in a reaction media composed of 80% myristic acid and 10% oleic acid. Lipozyme® RM IM catalyzed successfully 5 consecutive reactions before showing reduction of its synthetic activity at the 6th cycle. The end-product profile analysis confirmed the selectivity of Lipozyme® RM IM towards saturated fatty acids over unsaturated one and the formation of fructosyl monoester and diester of myristic acids. This study lays the ground of a sustainable approach for the acylation of myristic or longer saturated fatty acids with carbohydrates for a great potential as functional ingredients.

关键词： Low-solvent reaction media Lipozyme®RM IM Lipase-catalyzed esterification Carbohydrate fatty acid esters

Prevalence of and risk factors for erectile dysfunction in young nondiabetic obese men:results from a regional study

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Asian journal of Andrology 2020年第4期22卷 372-378页

作者： María Molina-Vega Maite Asenjo-Plaza María joséBanderas-Donaire María Dolores Hernández-Ollero Silvia Rodríguez-Moreno juan jálvarez-Millán Pablo cabezas-Sanchez Fernando Cardona-Díaz juan Alcaide-Torres Lourdes Garrido-Sánchez Daniel Castellano-Castillo Francisco j Tinahones joséC Fernández-García Department of Endocrinology and Nutrition Virgen de la Victoria University Hospital(IBIMA)Málaga UniversityMálaga 29010Spain Centro de Investigación Biomédica en Red de la Fisiopatología de la Obesidad y Nutrición(CIBEROBN) Instituto de Salud Carlos IIIMadrid 28029Spain Cruz de Humilladero Primary Care Center Málaga 29010Spain Teatinos Primary Care Center Málaga 29010Spain Chemical Sanitary Consulting(CQS Lab) Madrid 28003Spain

Erectile dysfunction(ED),a condition closely related to cardiovascular morbidity and mortality,is frequently associated with *** this study,we aimed to determine the prevalence of ED and evaluate the associated risk factors in a cohort of 254 young(18–49 years)nondiabetic obese(body mass index[BMI]≥30 kg m−2)men from primary *** function(International Index of Erectile Function[IIEF-5]questionnaire),quality of life(Aging Males'Symptoms[AMS scale]),and body composition analysis(Tanita MC-180MA)were *** testosterone was determined using high-performance liquid chromatography–mass *** logistic regression analysis was used to study the factors associated with *** prevalence was 42.1%.Subjects with ED presented higher BMI,waist circumference,number of components of the metabolic syndrome,AMS score,insulin resistance,and a more unfavorable body composition than those without *** logistic regression analysis showed that a pathological AMS score(odds ratio[OR]:4.238,P40%of subjects.A pathological AMS score,the degree of obesity,and age were positively associated with ED,while elevated HDL-cholesterol levels were inversely associated with the odds of presenting *** prospective studies are needed to evaluate the long-term consequences of ED in this population.

关键词： Aging Males'Symptoms score erectile dysfunction International Index of Erectile Function-5 questionnaire obesity testosterone

Impact of an acute hemodynamic response-guided protocol for primary prophylaxis of variceal bleeding

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World journal of Clinical Cases 2018年第13期6卷 611-623页

作者： josé Ignacio Fortea ángela Puente Patricia Ruiz Iranzu Ezcurra javier Vaquero Antonio Cuadrado María Teresa Arias-Loste joaquín cabezas Susana Llerena Paula Iruzubieta Carlos Rodríguez-Lope Patricia Huelin Fernando Casafont Emilio Fábrega javier Crespo Servicio de Aparato Digestivo Hospital Universitario Marques? de Valdecilla Instituto de Investigación Sanitaria Marqués de Valdecilla Centro de Investigación Biomédica Red de Enfermedades Hepáticas y Digestivas Laboratorio de Investigación en Hepatología y Gastroenterología Hospital General Universitario Gregorio Mara?ón-Instituto de Investigación Sanitaria Gregorio Mara?ón

AIM To evaluate the long-term outcome of an acute hemodynamic response-guided protocol in which acute responders to intravenous propranolol received traditional nonselective beta-blockers(NSBBs) and acute nonresponders received *** Retrospective review of a protocol for primary prophylaxis of variceal bleeding guided by the acute hemodynamic response to intravenous propranolol. Fifty-two acute responders treated with traditional NSBB(i.e. propranolol or nadolol) were compared with 24 acute nonresponders receiving carvedilol. A second hemodynamic study was performed in 27 and 13 patients, respectively. The primary endpoint was development of first or further decompensation. Secondary endpoints included death from any cause, association between acute and chronic hemodynamic response, and baseline clinical and laboratory variables related to the acute hemodynamic *** Acute responders and acute nonresponders presented similar 1, 2, and 3-year probabilities of first decompensation(NSBB: 0%, 13.7%, 26.1% vs carvedilol: 0%, 20%, 20%, P = 0.968) or further decompensation(21.2%, 26.1%, 40.9% vs 21.2%, 50.0%, 50.0%, P = 0.525). A previous episode of hepatic encephalopathy was the only independent predictor of decompensation [hazard ratio(95% confidence interval): 8.03(2.76-23.37)]. Mortality rates were similar in acute responders and acute nonresponders with compensated(P = 0.428) or decompensated cirrhosis(P = 0.429). No clinical, laboratory, endoscopic or hemodynamic parameter predicted the acute hemodynamic response. In patients receiving traditional NSBB, the acute and chronic changes of hepatic venous pressure gradient were correlated(r = 0.59, P = 0.001). Up to 69.2% of acute nonresponders gained chronic response with *** Early identification and treatment with carvedilol of acute nonresponders to intravenous propranolol improves the clinical outcome of this high-risk group of patients, probably due to its greater effects fo

关键词： Gastrointestinal hemorrhage Propranolol Carvedilol Liver cirrhosis Portal hypertension

模块表达序列标签技术的建立及相关水稻cDNA阵列的应用

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中国水稻科学 2004年第1期18卷 1-6页

作者：庄晓峰李德葆 cabezas DANIEL 戴承恩娄沂春董海涛浙江大学农业与生物技术学院生物信息与基因网络研究组浙江杭州310029

提出了一种新的表达序列标签制作技术———模块表达序列标签 (M EST)技术 ,利用该技术短时间内分离完成1985条水稻cDNA片段 ,制备完成相应的水稻cDNA阵列。实验证实 :该技术体系能成功分离目的基因 ,正确检测基因表达丰度的改变 ,并具... 详细信息

提出了一种新的表达序列标签制作技术———模块表达序列标签 (M EST)技术 ,利用该技术短时间内分离完成1985条水稻cDNA片段 ,制备完成相应的水稻cDNA阵列。实验证实 :该技术体系能成功分离目的基因 ,正确检测基因表达丰度的改变 ,并具备通过对基因群体表达模式的监测以实现对生物学事件的精确描述。M EST概念是对EST技术的完善和重要补充 ,运用M EST技术能有效利用生物信息学知识 ,加快基因克隆速率 ,为基因功能的研究提供手段和工具。

关键词：蛋白模体蛋白模块表达序列标签 cDNA阵列水稻