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Aquaculture and Fisheries 2021年第1期6卷 69-74页

作者： Mario Nieves-Soto Ricardo Lozano-Huerta Diana J.Lòpez-Peraza María a.medina-Jasso Miguel AHurtado-Oliva JoséF.Bermudes-Lizárraga Facultad de Ciencias del Mar Universidad Autónoma de SinaloaPaseo Claussen s/n.Los PinosMazatlánC.P.8200Mexico

Artemia is deficient in polyunsaturated fatty acids(PUFAs),particularly in arachidonic(ARA,20:4n-6),eicosapentaenoic(EPA,20:5n-3),and docosahexaenoic acid(DHA,22:6n-3).The aim of this study was to determine the optimal time in which the higher contents of PUFAs in juveniles of Artemia franciscana were obtained by the effect of enrichment with the tuna orbital oil *** enrichment periods were evaluated:3,6,9,12,15 and 18 h,in addition to a control treatment(0 h).The most abundant fatty acids in *** were monounsaturated(43.10%±4.35–52.92%±5.82%),followed by saturated(33.83%±1.71–42.33%±2.31%)and PUFAs(8.86%±2.83%–21.32%±2.38%).ARA decreased over the enrichment time;the maximum content was 5.74±0.37%at 3 h,which was not statistically different with respect to the content recorded at 0 *** highest content of EPA was at 3 h(6.47%±1.44%),without significant differences with the content registered at 0 h,while that from 6 h and until 15 h tended to decrease *** 6 h,the content of DHA(8.84%±2.72%)was significantly higher compared to the rest of the treatments,which did not differ among themselves,or with the *** to the 6 h and until 15 h,the content of PUFAs tended to decrease,which could indicate the metabolization of them by ***,coupled with the possible oxidation of these fatty acids in the enrichment solution.

关键词： Artemia franciscana juveniles Bioencapsulation Essential fatty acids Tuna orbital oil emulsion

Effect of Sn on synthesis of nanocrystalline Ti-based alloy with fcc structure

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Transactions of Nonferrous Metals Society of China 2020年第8期30卷 2119-2131页

作者： C.AGUILAR E.PIO a.medina C.PARRA R.MANGALARAJA P.MARTIN I.ALFONSO K.TELLO Departamento de Ingeniería Metalúrgica y de Materiales Departamento de Física(+)Universidad Técnica Federico Santa MaríaValparaísoChile Instituto de Investigación en Metalurgia y Materiales Universidad Michoacana de San Nicolás de HidalgoMoreliaMéxico Laboratorio de Cerámicos Avanzados y Nanotecnologia Departamento de Ingeniería de MaterialesUniversidad de ConcepciónConcepciónChile Instituto de Investigaciones en Materiales Universidad Nacional Autónoma de MéxicoCampus Morelia UNAMMoreliaMéxico

The effect of the amount of Sn on the formation of fcc phase in Ti-13 Ta-x Sn(x=3,6,9 and 12,at.%)alloys was *** alloys were synthesized by mechanical alloying using a planetary mill,jar and balls of stabilized *** Rietveld refinement,it was found that the obtained fcc phase has crystallite size smaller than 10 nm and microstrain larger than *** conditions are required to form an fcc phase in Ti-based *** all samples,the microstructure of the fcc phase consists of equiaxial crystallites with sizes smaller than 10 *** largest presence of fcc phase in the studied Ti alloy was found with 6 at.%Sn,because this alloy exhibits the largest microstrain(1.5×10-2)and crystallite size of 6.5 *** data reveal that a solid solution and an amorphous phase were formed during *** necessary conditions to promote the formation of solid solution and amorphous phases were determined using thermodynamic *** the amount of Sn increases,the energy required to form an amorphous phase varies from approximately 10 to approximately-5 k J/mol for 3 and 12 at.%Sn,*** thermodynamic calculations are in agreement with XRD patterns analysis and HRTEM results.

关键词： Ti-based alloy phase transformation fcc phase Rietveld analysis mechanical alloying

Performance Improvement of Artificial Neural Network Model in Short-term Forecasting of Wind Farm Power Output

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Journal of Modern Power Systems and Clean Energy 2020年第3期8卷 484-490页

作者： Sergio Velázquez medina Ulises Portero Ajenjo Department of Electronics and Automatics Engineering Universidad de Las Palmas de Gran CanariaCampus de Tafira s/n35017 Las Palmas de Gran CanariaCanary IslandsSpain School of Industrial and Civil Engineering University of Las Palmas de Gran CanariaCampus de Tafira s/n35017 Las Palmas de Gran CanariaCanary IslandsSpain

Due to the low dispatchability of wind power,the massive integration of this energy source in power systems requires short-term and very short-term wind power output forecasting models to be as efficient and stable as possible.A study is conducted in the present paper of potential improvements to the performance of artificial neural network(ANN)models in terms of efficiency and ***,current ANN models have been developed by considering exclusively the meteorological information of the wind farm reference station,in addition to selecting a fixed number of time periods prior to the *** this respect,new ANN models are proposed in this paper,which are developed by:varying the number of prior 1-h periods(periods prior to the forecasting hour)chosen for the input layer parameters;and/or incorporating in the input layer data from a second weather station in addition to the wind farm reference *** has been found that the model performance is always improved when data from a second weather station are *** mean absolute relative error(MARE)of the new models is reduced by up to 7.5%.Furthermore,the longer the forecasting horizon,the greater the degree of improvement.

关键词： Artificial neural networks(ANN) wind power forecasting model performance wind power output

Orientation of larval and juvenile horseshoe crabs Limulus polyphemus to visual cues: Effects of chemical odors

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Current Zoology 2010年第5期56卷 618-633页

作者： Julie M.medina Richard A.TANKERSLEY Department of Biological Sciences Florida Institute of Technology

Adult horseshoe crabs Limulus polyphemus have long served as models for the study of vision in marine arthropods. Yet, little is known about the ability of early life history stages to detect and respond to visual cues. We examined the visually directed movements of larvae and first stage juveniles to horizons containing dark visual targets of different sizes. The study tested the hypotheses that （1） larval and juvenile crabs can detect and respond to visual targets and （2） the direction of orientation varies with the presence of chemical cues associated with settlement habitats. Orientation of larval and juvenile crabs to rectangles subtending angles from 30--330~ was tested in a circular arena containing water that either lacked estuarine chemical cues （offshore water） or contained odors from aquatic vegetation or known predators. In the absence of chemical odors, larvae oriented toward and juveniles moved away from dark horizons subtending angles 〉 60~. When placed in water containing chemical odors from potential nursery habitats, including the seagrasses Halodule wrightii and Syringodium filiforme, crabs reversed their direction of orientation relative to their responses in offshore water. Odors from two known predators, the mummichug Fundulus grandis and blue crab Callinectes sapidus, had no affect on the orientation of larvae. Yet, juveniles responded to both odors by moving toward the visual target. Results support the hypothesis that the visual orientation of larval and juvenile horseshoe crabs changes upon exposure to habitat and predator cues and that the direction of the response undergoes an ontogenetic shift following metamorphosis

关键词： Orientation Visual cues Chemical odors

Biodiesel production from waste frying oil in sub- and supercritical methanol on a zeolite Y solid acid catalyst

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Frontiers of Chemical Science and Engineering 2013年第4期7卷 401-407页

作者： Jorge medina-VALTIERRA Jorge RAMIREZ-ORTIZ Department of Chemical & Biochemical Engineering Aguascalientes Institute of Technology Aguascalientes Ags. 20256 M6xico Academic Unit of Chemical Sciences Autonomous University of Zacatecas Zac. 98160 Mexico

Waste frying oil （WFO） is a very important feedstock for obtaining biodiesel at low cost and using WFO in transesterification reactions to produce biodiesel helps eliminate local environmental problems. In this study biodiesel was produced from WFO in sub- and super- critical methanol on a zeolite Y solid acid catalyst. The procedure was optimized using a design of experiments by varying the methanol to WFO molar ratio, the reaction temperature, and the amount of catalyst. Typical biodiesel yields varied from 83 to nearly 100% with methyl esters content ranging from 1.41-1.66mol.L-~ and typical dynamic viscosities of 22.1-8.2 cE Gas chromatography was used to determine the molecular composition of the biodiesel. The reaction products contained over 82 wt-% methyl esters, 4.2 wt-% free acids, 13.5 wt-% monoglycer- ides, and 0.3 wt-% diglycerides. The transesterification of WFO with methanol around its critical temperature combined with a zeolite Y as an acid catalyst is an efficient approach for the production of biodiesel with acceptable yields.

关键词： biodiesel methanol critical temperature,waste frying oil zeolite Y

GPU Accelerated Discontinuous Galerkin Methods for Shallow Water Equations

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Communications in Computational Physics 2015年第6期18卷 37-64页

作者： Rajesh Gandham David medina Timothy Warburton Department of Computational and Applied Mathematics Rice University6100 Main StreetMS-134HoustonTX-77005USA

We discuss the development,verification,and performance of a GPU accelerated discontinuous Galerkin method for the solutions of two dimensional nonlinear shallow water *** shallow water equations are hyperbolic partial differential equations and are widely used in the simulation of tsunami wave *** algorithms are tailored to take advantage of the single instruction multiple data(SIMD)architecture of graphic processing *** time integration is accelerated by local time stepping based on a multi-rate Adams-Bashforth scheme.A total variational bounded limiter is adopted for nonlinear stability of the numerical *** limiter is coupled with a mass and momentum conserving positivity preserving limiter for the special treatment of a dry or partially wet element in the ***,robustness and performance are demonstrated with the aid of test ***,we developed a unified multi-threading model *** kernels expressed in OCCA model can be cross-compiled with multi-threading models OpenCL,CUDA,and *** compare the performance of the OCCA kernels when cross-compiled with these models.

关键词： Shallow water equations discontinuous Galerkin positivity preserving slope limiting GPUs accelerators multi-threading

Asymmetric dimethylarginine as a mediator of vascular dysfunction in cirrhosis

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World Journal of Gastroenterology 2015年第32期21卷 9466-9475页

作者： Paloma Lluch Gloria Segarra Pascual medina Department of Gastroenterology and Hepatology and Institute of Health Research INCLIVA Hospital Clínico Universitario Valencia Department of Physiology University of Valencia and Institute of Health Research INCLIVA Hospital Clínico Universitario Valencia

Cirrhosis is associated with marked abnormalities in the circulatory function that involve a reduction in systemic vascular resistance. An important cause of this vasodilatation is the increased production or activity of nitric oxide(NO) in the splanchnic circulation. During portal hypertension and cirrhosis an increased endothelial NO synthase(e NOS) activity is demonstrated in splanchnic vessels. In contrast, the activity of e NOS in the cirrhotic liver is decreased, which suggests a different regulation of e NOS in the liver and in the splanchnic vessels. Asymmetric dimethylarginine(ADMA) is an endogenous NO inhibitor and higher plasma levels of ADMA are related to increased cardiovascular risk in both the general population and among patients with cirrhosis. It has been demonstrated that the liver is a key player in the metabolism of ADMA. This observation was further supported by investigations in human patients, showing a close correlation between ADMA plasma levels and the degree of hepatic dysfunction. ADMA is degraded to citrulline and dimethylamine by dimethylarginine dimethylaminohydrolases(DDAHs). DDAHs are expressed as type 1 and 2 isoforms and are widely distributed in various organs and tissues, including the liver. In this review, we discuss experimental and clinical data that document the effects of dimethylarginines on vascular function in cirrhosis. Our increasing understanding of the routes of synthesis and metabolism of methylarginines is beginning to provide insights into novel mechanisms of liver disease and allowing us to identify potential therapeutic opportunities.

关键词： Dimethylarginine dimethylaminohydrolase Nitric oxi

Updates on the hepatocyte growth factor/c-Met axis in hepatocellular carcinoma and its therapeutic implications

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World Journal of Gastroenterology 2018年第33期24卷 3695-3708页

作者： Javier A García-Vilas Miguelángel medina Department of Pediatrics University of AlbertaEdmonton T6G 2S2Canada Departamento de Biología Molecular y Bioquímica Facultad de CienciasAndalucía TechUniversidad de MálagaMálaga 29071Spain Unidad 741 de CIBER“de Enfermedades Raras”(CIBERER) Málaga 29071Spain Institute of Biomedical Research in Málaga Málaga 29071Spain

Hepatocellular carcinoma(HCC) is the fifth most common cancer and is the second leading cause of cancer death. Since the diagnosis of HCC is difficult, in many cases patients with HCC are diagnosed advanced stage of development. Hepatocyte growth factor(HGF)/c-mesenchymal-epithelial transition receptor(c-Met) axis is a key signaling pathway in HCC, either via canonical or non-canonical pathways. Available treatments against HCC based upon HGF/c-Met inhibition can increase patient lifespan, but do not reach the expected therapeutic benefits. In HCC, c-Met monomers can bind other receptor monomers, activating several noncanonical signaling pathways, leading to increased cell proliferation, invasion, motility, and drug resistance. All of these processes are enhanced by the tumor microenvironment, with stromal cells contributing to boost tumor progression through oxidative stress, angiogenesis, lymphangiogenesis, inflammation, and fibrosis. Novel treatments against HCC are being explored to modulate other targets such as microR NAs, methyltransferases, and acetyltransferases, which are all involved in the regulation of gene expression in cancer. This review compiles basic knowledge regarding signaling pathways in HCC, and compounds already used or showing potential to be used in clinical trials.

关键词： Hepatocellular carcinoma Hepatocyte growth factor/c-MET Tumor microenvironment c-Met

Assessment of compressive strength of jet grouting by machine learning

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第1期16卷 102-111页

作者： Esteban Diaz Edgar Leonardo Salamanca.medina Roberto Tomas Departamento de Ingeniería Civil Escuela Politécnica SuperiorUniversidad de AlicanteP.O.Box 99E-03080AlicanteSpain

Jet grouting is one of the most popular soil improvement techniques,but its design usually involves great uncertainties that can lead to economic cost overruns in construction *** high dispersion in the properties of the improved material leads to designers assuming a conservative,arbitrary and unjustified strength,which is even sometimes subjected to the results of the test *** present paper presents an approach for prediction of the uniaxial compressive strength(UCS)of jet grouting columns based on the analysis of several machine learning algorithms on a database of 854 results mainly collected from different research *** selected machine learning model(extremely randomized trees)relates the soil type and various parameters of the technique to the value of the compressive *** the complex mechanism that surrounds the jet grouting process,evidenced by the high dispersion and low correlation of the variables studied,the trained model allows to optimally predict the values of compressive strength with a significant improvement with respect to the existing ***,this work proposes for the first time a reliable and easily applicable approach for estimation of the compressive strength of jet grouting columns.

关键词： Jet grouting Ground improvement Compressive strength Machine learning

Study on Characteristics of Co-firing Ammonia/Methane Fuels under Oxygen Enriched Combustion Conditions

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Journal of Thermal Science 2018年第3期27卷 270-276页

作者： XIAO Hua WANG Zhaolin VALERa.medina Agustin BOWEN Philip J School of Engineering Cardiff University College of Energy Xiamen University

Having a background of utilising ammonia as an alternative fuel for power generation, exploring the feasibility of co-firing ammonia with methane is proposed to use ammonia to substitute conventional natural gas. However, improvement of the combustion of such fuels can be achieved using conditions that enable an increase of oxygenation, thus fomenting the combustion process of a slower reactive molecule as ammonia. Therefore, the present study looks at oxygen enriched combustion technologies, a proposed concept to improve the performance of ammonia/methane combustion. To investigate the characteristics of ammonia/methane combustion under oxygen enriched conditions, adiabatic burning velocity and burner stabilized laminar flame emissions were studied. Simulation results show that the oxygen enriched method can help to significantly enhance the propagation of ammonia/methane combustion without changing the emission level, which would be quite promising for the design of systems using this fuel for practical applications. Furthermore, to produce low computational-cost flame chemistry for detailed numerical analyses for future combustion studies, three reduced combustion mechanisms of the well-known Konnov's mechanism were compared in ammonia/methane flame simulations under practical gas turbine combustor conditions. Results show that the reduced reaction mechanisms can provide good results for further analyses of oxygen enriched combustion of ammonia/methane. The results obtained in this study also allow gas turbine designers and modellers to choose the most suitable mechanism for further combustion studies and development.

关键词： Ammonia/Methane Oxygen-enriched Combustion Reduced Mechanism Gas Turbine