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Surfactant-free synthesis of metallic bismuth spheres by microwave-assisted solvothermal approach as a function of the power level

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Frontiers of Materials Science 2016年第4期10卷 394-404页

作者： Miriam ESTRADa.flores Patricia SANTIAGO JACINTO Carmen M. REZA SAN GERMAN Luis RENDON VAZQUEZ Raul BORJA URBY Nicolas CAYETANO CASTRO Instituto de Investigaciones en Materiales Circuito Exterior S/N Zona de Institutos Ciudad Universitaria C.P. 04510 Mexico D.F. Mexico Instituto de Fisica Circuito de la Investigaci6n Cientffica Edificio Marcos MoshinskyLaboratorio de Materiales Nanoestructurados Ciudad Universitaria C.P. 04510 Mexico D.F. Mexico Escuela Superior de Ingenierfa Qufmica e Industrias Extractivas Unidad Profesional Adolfo L6pez Mateos Edif. Z-5 2do. Piso Instituto Politecnico Nacional C.P. 07738 Mexico D.F. Mexico Centro de Nanociencias y Micro y Nanotecnologfas. Instituto Politecnico Nacional Av. Luis Enrique Erro S/NUnidad Profesional Adolfo Lopez Mateos Zacatenco Delegaci6n Gustavo A. Madero C.P. 07738 Mexico D.F. Mexico

In the present work, the synthesis of micro- and nano-sized spheres of metallic bismuth by microwave-assisted solvothermal method is reported. The synthesis method was carried out at different power levels and at a unique frequency of microwave irradiation. The sphere sizes were controlled by the microwave power level and the concentration of dissolved precursor. Structural and morphological characterization was performed by SEM, HRTEM, EELS and XRD. The results demonstrated that rhombohedral zero valent Bi spheres were synthesized after microwave radiation at 600 and 1200 W. However, if the power level is decreased to 120 W, a monoclinic phase of Bi203 is obtained with a flake-like morphology. In comparison with a conventional hydrothermal process, the microwave-assisted solvothermal approach provides many advantages such as shorter reaction time, optimum manipulation of morphologies and provides a specific chemical phase and avoids the mixture of structural phases and morphologies which is essential for further applications such as drug delivery or functionalization with organic materials, thanks to its biocompatibility.

关键词： microwave oven power level metallic bismuth spherical structures mechanism of formation electron energy loss spectroscopy (EELS)

Luminescent Properties of the Mn<sup>2+</sup>Ion in Zinc Phosphate Glass

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Open Journal of Applied Sciences 2021年第11期11卷 1212-1217页

作者： Frida Lissete flores rivera Dulce Yolotzin Medina Velazquez Gabriela Verenice Arredondo Martínez Jorge Roberto Oliva Uc Carlos Eduardo Rodriguez Garcia Miguel Angel Barron-Meza Joan Reyes Miranda Autonomus Metropolitan University Material Area Mexico City Mexico Potosino Institute for Scientific and Technological Research Advanced Materials Division San Luis Mexico Faculty of Physics-Mathematics Autonomous University of Coahuila Saltillo Mexico

In the development of new optoelectronic devices, mainly those related to solid state technology (SSL), the generation of luminescent materials with high intensity in visible region and low cost is of vital importance. For this reason, this work presents the luminescent properties of zinc phosphate glasses doped with the manganese ion 2+. The manganese ion offers a series of advantages with respect to rare earths, such as a more accessible cost and an intense emission in the red color that make it a great candidate for the generation of new optoelectronic devices. The methodology for the synthesis is presented in this work, as well as its luminescent properties, for concentrations of 2%, 10%, 13% and 15% atomic.

关键词： Luminescence Manganese Advanced Glasses

Male age and strain affect ejaculate quality in the Mexican fruit fly

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Insect Science 2018年第4期25卷 703-711页

作者： Mariana Herrera-Cruz Solana Abraham Nicolas NuSez-Beverido Norma.flores-Estevez Martha Reyes-Hernandez Mayvi Alvarado Diana P6rez-Staples Catedra CONACYT- Facultad de Medicina y Cirugia Universidad Autonoma 'Benito Juarez' de Oaxaca Oaxaca Mexico Laboratorio de Investigaciones Ecoetologicas de Moscas de la Fruta y sus Enemigos Naturales (LIEMEN) PROIMI Tucuman Argentina CONICET Argentina INBIO TECA Universidad Veracruzana Xalapa Veracruz Mexico Instituto de Neuroetologia Universidad Veracruzana Xalapa Veracruz Mexico

Aging in all organisms is inevitable. Male age can have profound effects on mating success and female reproduction, yet relatively little is known on the effects of male age on different components of the ejaculate. Furthermore, in mass-reared insects used for the Sterile Insect Technique, there are often behavioral differences between mass-reared and wild males, while differences in the ejaculate have been less studied. The ejaculate in insects is composed mainly of sperm and accessory gland proteins. Here, we studied how male age and strain affected （i） protein quantity of testes and accessory glands, （ii） the biological activity of accessory gland products injected into females, （iii） sperm viability, and （iv） sperm quantity stored by females in wild and mass-reared Anastrepha ludens （Diptera： Tephritidae）. We found lower protein content in testes of old wild males and lower sperm viability in females mated with old wild males. Females stored more sperm when mated to young wild males than with young mass-reared males. Accessory gland injections of old or young males did not inhibit female remating. Knowledge of how male age affects different ejaculate components will aid our understanding on investment of the ejaculate and possible postcopulatory consequences on female behavior.

关键词： accessory glands age Anastrepha ludens mass-rearing sperm Tephritidae

Spatial Distribution of Fuel Models Based on the Conditional-Fuel-Loading Concept

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Journal of Environmental Protection 2018年第2期9卷 111-121页

作者： José Germán flores Garnica Instituto Nacional de Investigaciones Forestales Agrícolas y Pecuarias Guadalajara México

Fuel model mapping has followed in general two trends: 1) indirect inferences, where some factors, presumably associated with fuel production, are related to a given fuel model;and 2) experts consulting, which has been used to classify and to validate other people classifications. However, reliance on expert judgment implies a subjective approach. Thus, I propone the integration of geostatistic techniques and the Conditional-Fuels-Loading concept (CFL) to define a more objective perspective in the fuel-model mapping. The information used in this study was collected in a forest of Chihuahua, Mexico, where fuels were inventoried in 554 (1000 m2) sample plots. These sample plots were classified using the CFL;and ordinary kriging (Gaussian, spherical and exponential) was used to interpolate the fuel-model values. Using the Akaike’s Information Criterion the spherical model performed best. The methodology allowed a finer definition of spatial distribution of fuel models. Some advantages of the CFL are: 1) it is based on actual fuel loads, and not only on vegetation structure and composition;2) it is objective and avoids the bias of different classifiers (experts);and 3) it avoids the need of the advice of experts.

关键词： Validation Fuel Mapping Geostatistics Ordinary Kriging

A CFD study of the transport and fate of airborne droplets in a ventilated office:The role of droplet−droplet interactions

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Frontiers of Environmental Science & Engineering 2022年第3期16卷 49-62页

作者： Allan Gomez-flores Gukhwa Hwang Sadia Ilyas Hyunjung Kim Department of Environment and Energy Jeonbuk National UniversityJeonju Jeonbuk 54896Republic of Korea Department of Mineral Resources and Energy Engineering Jeonbuk National UniversityJeonju Jeonbuk 54896Republic of Korea

Previous studies reported that specially designed ventilation systems provide good air quality and safe environment by removing airborne droplets that contain viruses expelled by infected *** water droplets can be stable in the environment and remain suspended in air for prolonged *** between droplets may occur and droplet interactions should be ***,the previous studies focused on other physical phenomena(air flow,drag force,evaporation)for droplet transport and neglected droplet *** this work,we used computational fluid dynamics(CFD)to simulate the transport and fate of airborne droplets expelled by an asymptomatic person and considered droplet *** drag with turbulence for prediction of transport and fate of droplets indicated that the turbulence increased the transport of 1μm droplets,whereas it decreased the transport of 50μm *** contrast to only considering drag and turbulence,consideration of droplet interactions tended to increase both the transport and *** the length scale of the office is much larger than the droplet sizes,the droplet interactions,which occurred at the initial stages of release when droplet separation distances were shorter,had a significant effect in droplet fate by considerably manipulating the final locations on surfaces where droplets ***,it is proposed that when an exact prediction of transport and fate is required,especially for high droplet concentrations,the effects of droplet interactions should not be ignored.

关键词： Droplet interactions Aerosols Colloids CFD Transport Fate

Structure and Density Analysis of a Semi Desert Ecosystem Disturbed by Fire

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Open Journal of Forestry 2018年第2期8卷 155-166页

作者： José Germán flores Garnica Instituto Nacional de Investigaciones Forestales Agrícolas y Pecuarias Guadalajara Jalisco México

In Mexico, forest ecosystems are disturbed by fires and generally these are considered to have negative impacts. However, it is important to consider that fire is an element of these ecosystems, and is important for its functionality. So it should be understood that in many cases the effects of a forest fire are beneficial, which can be determined through studies of population dynamics of these ecosystems. However, most of these studies currently focused only on aspects of species composition, with few cases concerning the analysis of the structure and density. In this study, a comparative analysis of the vegetation showed that conditions prevailing between burned and unburned areas of a site covered by microphyll desert species (shrubs and mesquite). The results suggest that the structure and density conditions of vegetation between burned and unburned areas are not statistically different. This is highlighted because one year after the fire occurred there is no evidence that fire had altered the structure and density of vegetation. Moreover, both in burned and unburned areas, vegetation had a healthy condition. Finally, although this may suggests that the fire was of low intensity, which resulted in a low impact on vegetation, in future studies it is recommended to determine if the same results are observed under different possible fire behavior and intensity.

关键词： Population Dynamic Forest Fire Semi-Desert

Implementation of Neural Networks in Time Series to Generate a Portfolio of Investment in Cryptocurrencies

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Journal of Mathematics and System Science 2020年第1期10卷 1-12页

作者： Jose B.Hernandez C. Jorge a.flores S. Jesus Lares Escuela de Matematicas Universidad Central de VenezuelaLos Chaguaramos1020CaracasVenezuela Centro de Investigacion en Matematicas A.C.Unidad Monterrey.Av.Alianza Centro 502PIIT 66628ApodacaNuevo LeonMexico EY Wavespace MadridSpain Parallel and Distributed Computing Center Universidad Central de VenezuelaLos Chaguaramos1020CaracasVenezuela

The present work aims to implement two types of neural networks and an analysis of a multivariate time series model of VAR type to predict the price of cryptocurrencies like Bitcoin,Dash,Ethereum,Litecoin,and *** subject has been popular in recent years due to the rapid price fluctuations and the immense amount of money involved in the cryptocurrencies *** technologies have been developed around cryptocurrencies,with Blockchain rising as the most *** has been implementing other information technology projects which have helped to open a wide variety of job positions in some industries.A“New Economy”is emerging and it is important to study its basis in order to establish the pillars that help us to understand its behavior and be ready for a new era.

关键词： Neural networks time series cryptocurrencies VAR models

Acute Nephronia and Renal Abscesses in Children from Quito, Ecuador

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Advances in Infectious Diseases 2021年第4期11卷 375-383页

作者： Adriana Arnao Maria Augusta Guerrero Nathaly Arias Piedad Villacís Katia Rivas Mariana.flores Jhoana rivera Jack Saltos Gloria Soto Jorge García Edison Aymacaña Diego Bonilla Marcelo Merizalde Cristina Garzón Hospital Axxis Quito Ecuador Hospital Vozandes Quito Ecuador Hospital de los Valles Quito Ecuador Hospital Metropolitano Quito Ecuador

Renal abscess and nephronia are uncommon diseases in children and with unknown global prevalence. Nephronia represents an intermediate state between pyelonephritis and renal abscess. Prompt diagnosis is important to prevent morbidity and mortality (sepsis, renal injury, death). Scientific advances have made these entities more evident, although they may still be underdiagnosed. Patients with this disease require prolonged intravenous antibiotic therapy and potentially surgical resolution, mostly when their size is bigger than 3 - 5 cm when therapy with intravenous antibiotics alone fails and they are accessible to percutaneous drainage. We describe five cases of pediatric patients from four private hospitals in Quito, Ecuador followed during a one-year period. In every case, the diagnosis was suspected mostly because of persistent fever, abdominal pain, severe leukocytosis and/or elevated inflammation biomarkers. Only one of them had a previous history of urinary tract malformation while in another one malformation was revealed in his actual admission. Every case had microbiologic isolation. All of them recovered successfully. To our knowledge, in our country, there are no previous reports of these diseases in pediatric patients, and worldwide, there is scarce data. Our aim is to alert doctors who work with children to be aware of this condition.

关键词： Infectious Diseases Kidney Pediatric Nephrology Nephronia Renal Abscess Ecuador

Intestinal pseudo-obstruction in patients with systemic lupus erythematosus: A real diagnostic challenge

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World Journal of Gastroenterology 2014年第32期20卷 11443-11450页

作者： Carlos Alberto García López Fernando Laredo-Sánchez José Malagón-Rangel Miguel G flores-Padilla Haiko Nellen-Hummel Department of Internal Medicine Specialities Hospital National Medical Centre "Siglo XXI" Mexican Social Security Institute Distrito Federal 06720 México

Intestinal pseudo-obstruction secondary to systemic lupus erythematosus(SLE) is a rare syndrome described in recent decades. There are slightly over 30 published cases in the English language literature, primarily associated with renal and hematological disease activity. Its presentation and evolution are a diagnostic challenge for the clinician. We present four cases of intestinal pseudo-obstruction due to lupus in young Mexican females. One patient had a previous diagnosis of SLE and all presented with a urinary tract infection of varying degrees of severity during their evolution. We consider that recognition of the disease is of vital importance because it allows for establishing appropriate management, leading to a better prognosis and avoiding unnecessary surgery and complications.

关键词： Intestinal pseudo-obstruction Systemic lupus erythematosus Uretero-hydronephrosis Urinary tract infection Diagnostic challenge