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frontiers of Structural and Civil Engineering 2022年第10期16卷 1249-1266页

作者： Soheila KOOKALANI Bin CHENG Jose Luis chavez TORRES Department of Civil Engineering Shanghai Jiao Tong UniversityShanghai 200240China Department of Civil Engineering Technical University of LojaLoja 110102Ecuador

The prediction of structural performance plays a significant role in damage assessment of glass fiber reinforcement polymer(GfRP)elastic gridshell *** learning(ML)approaches are implemented in this study,to predict maximum stress and displacement of GfRP elastic gridshell *** ML algorithms,including linear regression(LR),ridge regression(RR),support vector regression(SVR),K-nearest neighbors(KNN),decision tree(DT),random forest(Rf),adaptive boosting(AdaBoost),extreme gradient boosting(XGBoost),category boosting(CatBoost),and light gradient boosting machine(LightGBM),are implemented in this *** features of structural performance considered in this study are the maximum stress as f1(x)and the maximum displacement to self-weight ratio as f2(x).A comparative study is conducted and the Catboost model presents the highest prediction ***,interpretable ML approaches,including shapely additive explanations(SHAP),partial dependence plot(PDP),and accumulated local effects(ALE),are applied to explain the *** is employed to describe the importance of each variable to structural performance both locally and *** results of sensitivity analysis(SA),feature importance of the CatBoost model and SHAP approach indicate the same parameters as the most significant variables for f1(x)and f2(x).

关键词： machine learning gridshell structure regression sensitivity analysis interpretability methods

Evaluation of the ability of arsenic species to traverse cell membranes by simple diffusion using octanol-water and liposome-water partition coefficients

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Journal of Environmental Sciences 2016年第11期28卷 222-232页

作者： Teresa chavez-Capilla William Maher Tamsin Kelly Simon foster Ecochemistry Laboratory Institute for Applied Ecology University of Canberra Canberra ACT 2601 Australia National Centre for forensic Studies Faculty of Education Science Technology and Mathematics University of Canberra CanberraACT 2601 Australia

Arsenic metabolism in living organisms is dependent on the ability of different arsenic species to traverse biological membranes. Simple diffusion provides an alternative influx and efflux route to mediated transport mechanisms that can increase the amount of arsenic available for metabolism in cells. Using octanol-water and liposome-water partition coefficients, the ability of arsenous acid, arsenate, methylarsonate, dimethylarsinate, thio-methylarsonate, thiodimethylarsinic acid, arsenotriglutathione and monomethylarsonic diglutathione to diffuse through the lipid bilayer of cell membranes was investigated. Molecular modelling of arsenic species was used to explain the results. All arsenic species with the exception of arsenate, methylarsonate and thio-methylarsonate were able to diffuse through the lipid bilayer of liposomes, with liposome-water partition coefficients between 0.04 and 0.13. Trivalent arsenic species and thio-pentavalent arsenic species showed higher partition coefficients, suggesting that they can easily traverse cell membranes by passive simple diffusion. Given the higher toxicity of these species compared to oxo-pentavalent arsenic species, this study provides evidence supporting the risk associated with human exposure to trivalent and thio-arsenic species.

关键词： ArsenicLiposomesPartition coefficientsPassive simple diffusionTrivalent arsenic speciesThio-arsenic species

Hepatic hemangioma:What internists need to know

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World Journal of Gastroenterology 2020年第1期26卷 11-20页

作者： Monica Leon Luis chavez Salim Surani Centro Medico ABC Ciudad de MexicoCDMX 01120Mexico Department of Internal Medicine Texas Tech University Health Sciences CenterEl PasoTX 79905United States Texas A&M University Corpus ChristiTX 78405United States

Hepatic hemangioma(HH)is the most common benign liver tumor and it is usually found incidentally during radiological *** tumor arises from a vascular malformation;however,the pathophysiology has not been clearly *** usually correlate with the size and location of the *** commonly the presence of a large HH may cause life-threatening *** diagnosis can be established by the identification of HH hallmarks in several imaging *** patients that present with abdominal symptoms other etiologies should be excluded first before attributing HH as the *** asymptomatic patient’s treatment is not required and follow up is usually reserved for HH of more than 5 *** patients can be managed surgically or with other non-surgical modalities such as transcatheter arterial embolization or radiofrequency *** surgery has shown to have fewer complications as compared to hepatectomy or other surgical *** of the tumor is seen in less than 40%.Hormone stimulation may play a role in HH growth;however,there are no contraindications for hormonal therapy in patients with HH due to the lack of concrete *** clinicians encounter this condition,they should discern between observation and surgical or non-surgical management based on the clinical presentation.

关键词： Hepatic hemangioma Liver masses Liver Vascular lesion

Abdominal compartment syndrome among surgical patients

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World Journal of Gastrointestinal Surgery 2021年第4期13卷 330-339页

作者： Monica Leon Luis chavez Salim Surani Department of Medicine Centro Medico ABCCiudad de Mexico 01120Mexico Department of Medicine University of TexasEl PasoTX 79905United States Department of Medicine Texas A&M UniversityCorpus ChristiTX 78405United States

Abdominal compartment syndrome(ACS)develops when organ failure arises secondary to an increase in intraabdominal *** abdominal pressure is determined by multiple factors such as blood pressure,abdominal compliance,and other factors that exert a constant pressure within the abdominal *** conditions in the critically ill may increase abdominal pressure compromising organ perfusion that may lead to renal and respiratory *** surgical and trauma patients,aggressive fluid resuscitation is the most commonly reported risk factor to develop *** conditions that have also been identified as risk factors are ascites,hemoperitoneum,bowel distention,and large *** patients with abdominal trauma possess a higher risk of developing intra-abdominal hypertension(IAH).Certain surgical interventions are reported to have a higher risk to develop IAH such as damage control surgery,abdominal aortic aneurysm repair,and liver transplantation among *** monitoring of organ function and intra-abdominal pressure(IAP)allows clinicians to diagnose ACS rapidly and intervene with target-specific management to reduce *** decompression followed by temporary abdominal closure should be considered in all patients with signs of organ *** is still a great need for more studies to determine the adequate timing for interventions to improve patient outcomes.

关键词： Intra-abdominal hypertension Abdominal compartment syndrome Intraabdominal pressure Open abdomen treatment Multiple organ failure Surgical decompression

Very-early-stage Hepatocellular Carcinoma,Are We at Long Last on Route for Achieving Better Patient Outcomes?

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Journal of Clinical and Translational Hepatology 2021年第2期9卷 141-142页

作者： Paulina Vidal-Cevallos Norberto chavez-Tapia Obesity and Digestive Disease Unit Medica Sur Clinic and FoundationMexico CityMexico

Hepatocellular carcinoma(HCC)represents∼90%of the primary liver cancer cases,and 90%of HCC cases occur in patients with chronic liver disease.1 It also represents the sixth most common cancer(4.7%)and the third leading cause of cancer-related death globally(8.3%).2 More troubling,the global incidence and mortality rates have been increasing since 1990.3 In the United States,the highest average annual percentage change(known as AAPC)reported between 2000 and 2012 involved individuals between 55 and 59 years of age(AAPC:8.9%;95%confidence interval:7.1–10.7%).

关键词： Carcinoma mortality cancer

Translational approaches: from fatty liver to non-alcoholic steatohepatitis

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World Journal of Gastroenterology 2014年第27期20卷 9038-9049页

作者： Natalia Rosso Norberto C chavez-Tapia Claudio Tiribelli Stefano Bellentani fondazione Italiana fegato 34149 Trieste Italy Obesity and Digestive Diseases Unit Médica Sur Clinic and FoundationMexico 14050 México Department of Medical Sciences University of Trieste Department of Gastroenterology and Endoscopy Azienda USL di ModenaOspedale "Ramazzini" 41012 Carpi (Modena) Italy

Over the past few decades, non-alcoholic fatty liver disease(NAfLD) has become one, if not the most common,cause of chronic liver disease affecting both adults and children. The increasing number of cases at an early age is the most worrying aspect of this pathology, since it provides more time for its evolution. The spectrum of this disease ranges from liver steatosis to steatohepatitis, fibrosis and in some cases, hepatocellular carcinoma. NAfLD may not always be considered a benign disease and hepatologists must be cautious in the presence of fatty liver. This should prompt the use of the available experimental models to understand better the pathogenesis and to develop a rational treatment of a disease that is dangerously increasing. In spite of the growing efforts, the pathogenesis of NAfLD is still poorly understood. In the present article we review the most relevant hypotheses and evidence that account for the progression of NAfLD to non-alcoholic steatohepatitis(NASH) and fibrosis. The available in vitro and in vivo experimental models of NASH are discussed and revised in terms of their validity in translational studies. These studies must be aimed at the discovery of the still unknown triggers or mediators that induce the progression of hepatic inflammation, apoptosis and fibrosis.

关键词： fatty Liver Obesity Metabolic syndrome Inflammation In vitro Experimental model

Incidence rate of prostate cancer in men treated for erectile dysfunction with phosphodiesterase type 5 inhibitors： retrospective analysis

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Asian Journal of Andrology 2013年第2期15卷 246-248,I0008页

作者： Anthony H chavez K Scott Coffield M Hasan Rajab Chanhee Joe Departments of Urology Scott & White Healthcare Temple Texas 76508 USA Departments of Biostatistics Scott & White Healthcare Temple Texas 76508 USA Deparment of Biostatistics College of Medicine Alfaisal University Riyadh 11533 Saudi Arabia

The purpose of this study was to determine the incidence rate of prostate cancer among men with erectile dysfunction （ED） treated with phosphodiesterase type 5 inhibitors （PDE-5i） over a 7-year period vs. men with ED of the same age and with similar risk factors who were not treated with PDE-5i. In a retrospective review of electronic medical records and billing databases between the years 2000 and 2006, men with ED between the ages of 50 and 69 years and no history of prostate cancer prior to 2000 were identified. These individuals were divided into two groups： 2362 men who had treatment with PDE-5i, and 2612 men who did not have treatment. Demographic data in each group were compared. During the study period, 97 （4.1%） men with ED treated with PDE-5i were diagnosed with prostate cancer compared with 258 （9.9%） men with ED in the non-treated group （P〈00001）. A higher percentage of African Americans were treated with PDE-5i vs. those who were not （10.5% vs. 7.1%; P〈O.O001）. The PDE-5i group had lower documented diagnosis of elevated prostate-specific antigen （10.0% vs. 13.1%; P=-0.0008） and higher percentage of benign prostatic hyperplasia （38.4% vs. 35.1%; P=0.0149）. Men with ED treated with PDE-5i tended to have less chance （adjusted odds ratio： 0.4; 95% confidence intervals： 0.3-0.5; P〈0.0001） of having prostate cancer. Our data suggest that men with ED treated with PDE-5i tended to have less of a chance of beine diaenosed with orostate cancer. further research is warranted.

关键词： erectile dysfunction (ED) phosphodiesterase 5 inhibitors (PDE-5i) prostate cancer prostatic neoplasms

Effects of yttria content on the CMAS infiltration resistance of yttria stabilized thermal barrier coatings system

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Journal of Materials Science & Technology 2020年第8期36卷 74-83页

作者： Juan JGomez chavez Ravisankar Naraparaju Peter Mechnich Klemens Kelm Uwe Schulz C.V.Ramana University of Texas at El Paso Department of Mechanical EngineeringEl PasoTX79968USA German Aerospace Center(DLR) Institute of Materials ResearchCologne51170Germany

The effects of YO(1.5)doping in yttria-zirconia based thermal barrier coatings(TBCs)against CMAS interaction/infiltration are *** TBCs with an YO(1.5)content ranging from 43–67 mol.%(balance Zr O2)were produced by electron beam physical vapor deposition(EB-PVD)*** results reveal a trend of higher apatite formation probability with the higher free YO(1.5)available in the yttriazirconia ***,the infiltration resistance and amount of consumed coating appears to be strongly dependent on the YO(1.5)content in the *** thinnest reaction layer and lowest infiltration was found for the highest produced 67 YO(1.5)*** XRD experiments with volcanic ash/YO(1.5)powder mixtures with higher yttria contents than in the coatings(80 YO(1.5)and pure YO(1.5))also showed higher apatite formation with respect to increasing yttria *** threshold composition to promote apatite-based reaction products was found to be around 50 YO(1.5)in zirconia which was proved in the coatings and XRD powder *** YO(1.5)-ZrO2-fe O-TiO2 bearing zirconolite-type phase was formed as a reaction product for all the coating compositions which implicates that TiO2 in the melt acts as a trigger for zirconolite *** phase could be detrimental for CMAS/volcanic ash infiltration resistance since it can be formed alongside with apatite which controls or limits the amount of Y^(3+)available for glass *** fe rich garnet phase containing all the possible elements exhibited a slower nucleation compared to apatite and its growth was enhanced with slow cooling *** implications of phase stability and heat treatment effects on the reaction products are discussed for tests performed at 1250°C.

关键词： CMAS Volcanic ash Infiltration Electron beam physical vapor deposition Thermal barrier coating

Energy efficient and delay aware ternary-state transceivers for aerial base stations

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Digital Communications and Networks 2019年第1期5卷 40-50页

作者： Nahina Islam Kandeepan Sithamparanathan Karina Gomez chavez James Scott Hamid Eltom School of Electrical and Computer Engineering RMIT University Melbourne Australia Data61 CSIRO Melbourne Australia

In recent times, Aerial Base Stations(AeBSs) are being investigated to provide wireless coverage to terrestrial radio terminals. There are many advantages of using aerial platforms to provide wireless coverage, including larger coverage in remote areas and better line-of-sight conditions, etc. Energy is a scarce resource for the AeBSs, hence the wise management of energy is quite beneficial for the aerial network. In this context, we study the means of reducing the total energy consumption by designing and implementing an energy efficient AeBSs as presented in this paper. Implementing the sleep mode in the Base Stations (BSs) has been proven to be a very good approach for improving the energy efficiency and we propose a novel strategy for further improving energy efficiency by considering ternary state transceivers for AeBSs. Using the three state model, we propose a Markov Decision Process (MDP) based algorithm, which intelligently switches among three states of the transceivers based on the offered traffic meanwhile maintaining a prescribed minimum channel rate per user. We define a reward function for the MDP, which helps us to get an optimal policy for selecting a particular mode for the transceivers of the AeBS. Considering an AeBS with transceivers whose states are changeable, we perform simulations to analyse the performance of the algorithm. Our results show that, compared with the always active model, around 40% gain in the energy efficiency is achieved by using our proposed MDP algorithm together with the three-state transceivers model. We also show the energy-delay tradeoff in order to design an efficient AeBS.

关键词： Aerial base station UAV Green communication Sleep mode Markov decision process Energy efficiency Energy delay tradeoff