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The Influence of the Precipitation Heat Treatment Temperature on the Metallurgical, Microstructure, Thermal Properties, and Microhardness of an Alpha Brass

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Materials Sciences and Applications 2018年第4期9卷 440-454页

作者： Ignacio Rojas-Rodríguez Alberto Lara-Guevara Mauricio Salazar-Sicacha Julio Cesar Mosquera-Mosquera Minerva Robles-Agudo Cristian Ramirez-Gutierrez Mario Rodríguez-García División Industrial Universidad Tecnológica de Querétaro Querétaro México División de Posgrado Facultad de Informática Universidad Autónoma de Querétaro Querétaro México Programa de Física Universidad del Quindío Armenia Colombia Catedras Conacyt Universidad Tecnológica de Querétaro Querétaro México Posgrado en Ciencia e Ingeniería de Materiales Centro de Física Aplicada y Tecnología Avanzada Universidad Nacional Autónoma De México Campus Juriquilla Querétaro México Departamento de Nanotecnología Centro de Física Aplicada y Tecnología Avanzada Universidad Nacional Autónoma de México Campus Juriquilla Querétaro México

Metals obtain optimum conditions of metallurgical and physical properties through a heat treatment. Brass is one of the copper alloys which has many applications in everyday life and in the industry. Brass is one of the copper alloys which has many applications in everyday life and the industry. In this work, the influence of the precipitation heat treatment temperature on the metallurgical microstructure, structure, thermal properties, and microhardness of an alpha brass is analyzed. Samples were heat treated by precipitation for 2 h at 300°C, 400°C, 500°C, 600°C, and 700°C. The best mechanical properties were found at 500°C of precipitation heat treatment temperature. Specimens were characterized by scanning electron microscopy, X-ray diffraction, Vickers microhardness, photothermal radiometry, and photoacoustic to study the thermal diffusivity and conductivity, as well as the heat capacity. The inverse of the full width at the half maximum analysis showed that the crystallinity decreased as the precipitation heat treatment temperature increased. Metallurgical microstructure and microhardness were correlated to the precipitation heat treatment temperatures to determine the effect on the metallurgical and mechanical properties, as well as the effect on the thermal properties of alpha brass.

关键词： Alpha Brass Kunial Brass Crystallinity Photoacoustic Precipitation Heat Treatment X Ray Diffraction

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Crystallographic Study of the TiO<sub>2</sub>Obtained by Different Synthesis Methods

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Journal of Materials Science and Chemical Engineering 2013年第6期1卷 30-37页

作者： Fidel Alejandro Cortez-Lorenzo Miguel Galván Ruiz Rufino Nava Mendoza Mario Enrique Rodriguez García Rodrigo Rafael Velazquez Castillo Centro de Física Aplicada y Tecnología Avanzada UNAM Campus Juriquilla Querétaro México División de Investigación y Posgrado Facultad de Ingeniería Universidad Autónoma de Querétaro Querétaro México División de Investigación y Posgrado Facultad de Ingeniería Universidad Autónoma de Querétaro Querétaro México CBTis 145 San Juan del Río Querétaro México

In this work, the crystal structure of titanium dioxide was studied, and the effect of the different synthesis routes on the microstructure and morphology of the nanostructures was analyzed. Samples characterization was carried out by X-ray diffraction by powders (XRD) to determine the different crystalline phases contented in the samples and using scanning electron microscopy (SEM), the morphology and topology of all samples were studied. XRD results were analyzed through Eva provided by Bruker to determine the average crystallite size. The results portrayed here showed that all the synthesis process produced anatase nanostructures with an average crystallite size smaller than 27 nm. Synthesized powders presented similar morphologies in all cases and they were homogeneous in their chemical composition.

关键词： Anatase Sol-Gel Hydrothermal Assisted Microwaves Crystallization

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Sensory neurons in the spinal cord of nominal female embryos in the marine turtle Lepidochelys olivacea respond to shifts in incubation temperature:implications for temperature dependent sex determination

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Advances in Bioscience and Biotechnology 2011年第1期2卷 1-7页

作者： Francisco Jimenez-Trejo Leonora Olivos-Cisneros Julieta Mendoza-Torreblanca Sofia Diaz-Cintra Esperanza-Melendez-Herrera Armida Baez-Saldana Patricia Padilla Cortes Gabriel Gutierrez-Ospina Alma Lilia Fuentes-Farias Departamento de Biologia Facultad de QuimicaUniversidad Nacional Autonoma de MexicoMexico D.F.Mexico 04510 Departamento de Biologia Celular y Fisiologia Instituto de Investigaciones BiomedicasUniversidad Nacional Autonoma de MexicoMexico D.F.Mexico 04510 Departamento de Neuroquimica Instituto Nacional de PediatriaMexicoDF.Mexico 04530 Departamento de Neurobiologia del Desarrollo y Neurofisiologia Instituto de NeurobiologiaUniversidad Nacional Autonoma de MexicoCampus UNAM-JuriquillaJuriquillaQueretaro Mexico AP.1-1141 Laboratorio de Invertebrados y Ecofisiologia Animal Facultad de BiologiaUniversidad Michoacana de San Nicolas de HidalgoMoreliaMichoacanMexico 58040 Unidad de Cromatografia Liquida de Alta Resolucion Instituto de Investigaciones BiomedicasUniversidad Nacional Autonoma de MexicoMexico D.F.Mexico 04510

Gonadal determination in marine turtles depends on incubation temperature. The mechanisms that spark off this process remain unclear. Previously, we proposed that sensory nerves reaching the gonadal primordium in nominal female embryos of Lepidochelys (L) olivacea may sense and signal incubation temperature. These nerves could later trigger ovarian determination by releasing neurotransmitters in a code constructed based on the thermal information (Gutierrez-Ospina et al., Acetylcholinesterase-positive innervation is present at the undifferentiated stages of the sea turtle Lepidochelys olivacea embryo gonads: implications for temperature-dependent sex determination, J. Comp. Neurol. 410 (1999) 90-98). The hypothesis briefly described, however, has been recently refuted under weak theoretical grounds and experimental misinterpretations (see introduction). Here, we present preliminary results that show that nominal female embryos have sensory neurons located in the dorsal horn laminae I and II of the lumbar spinal cord that display increased c-Fos-like immuno-staining after being incubated either at 15°C or 50°C. Because these spinal neurons are the primary central target of dorsal root ganglion neurons that innervate the urogential crest, these observations keep open the possibility that gonadal sensory nerves indeed signal thermal information that could later be used to trigger or instruct ovarian specification in marine turtles.

关键词： Reptiles Ovarian Determination c-Fos Incubation Temperature Sensory Neurons

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Tibolone modulates neuronal plasticity through regulating Tau, GSK3β/Akt/PI3K pathway and CDK5 p35/p25 complexes in the hippocampus of aged male mice

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Neural Regeneration Research 2017年第4期12卷 588-595页

作者： Teresa Neri-Gomez Judith Espinosa-Raya Sofia Diaz Cintra Julia Segura-Uribe Sandra Orozco-Suarez Juan Manuel Gallardo Christian Guerra-Araiza Unidad de Investigación Médica en Farmacología Hospital de Especialidades Centro Médico Nacional Siglo XXI Instituto Mexicano del Seguro Social Ciudad de México México Laboratorio de Farmacología Conductual Escuela Superior de Medicina Instituto Politécnico Nacional Plan de San Luis y Díaz Mirón Col. Sto. Tomás Ciudad de México México Departamento de Neurobiología del Desarrollo y Neurofisiología Instituto de Neurobiología Universidad Nacional Autónoma de México Campus Juriquilla Querétaro Querétaro México Enfermedades Neurológicas (Neurological Diseases) Hospital de Especialidades Centro Médico Nacional Siglo XXI Instituto Mexicano del Seguro Social Ciudad de México México Enfermedades Nefrológicas (Kidney Diseases) Hospital de Especialidades Centro Medico Nacional Siglo XXI Instituto Mexicano del Seguro Social Ciudad de Mexico Mexico

Aging is a key risk factor for cognitive decline and age-related neurodegenerative disorders. Also, an age-related decrease in sex steroid hormones may have a negative impact on the formation of neurofibrillary tangles （NFTs）; these hormones can regulate Tau phosphorylation and the principal kinase GSK3β involved in this process. Hormone replacement therapy decreases NFTs, but it increases the risk of some types of cancer. However, other synthetic hormones such as tibolone （TIB） have been used for hormone replacement therapy. The aim of this work was to evaluate the long-term effects of TIB （0.01 mg/kg and 1mg/kg, intragastrically for 12 weeks） on the content of total and hyperphosphorylated Tau （PHF-1） proteins and the regulation of GSK3β/Akt/PI3K pathway and CDK5/p35/p25 complexes in the hippocampus of aged male mice. We observed that the content of PHF-1 decreased with TIB administration. In contrast, no changes were observed in the active form of GSK3β or PI3K. TIB decreased the expression of the total and phosphorylated form of Akt while increased that of p110 and p85. The content of CDK5 was differentially modified with TIB： it was increased at low doses and decreased at high doses. When we analyzed the content of CDK5 activators, an increase was found on p35; however, the content of p25 decreased with administration of low dose of TIB. Our results suggest a possible mechanism of action of TIB in the hippocampus of aged male mice. Through the regulation of Tau and GSK3β/Akt/PI3K pathway, and CDK5/p35/p25 complexes, TIB may modulate neuronal plasticity and regulate learning and memory processes.

关键词： nerve regeneration Tibolone hippocampus aged mice sex steroids Akt GSK3β PI3K neuralplasticity Tau neurofibrillary tangles neural regeneration

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Chilean crude extract of <i>Ruta graveolens</i>generates vasodilatation in rat aorta at subtoxic cellular concentrations

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Advances in Bioscience and Biotechnology 2013年第1期4卷 29-36页

作者： Ignacio Jofré Fernández Patricia Navarrete Gómez Jorge Parodi Fernando Romero Mejía Raúl Salvatici Salazar Center of Neurosciences and Peptides Biology Faculty of Medicine Universidad de La Frontera Temuco Chile Laboratorio de Fisiología de la Reproducción Núcleo de Producción Alimentaria Escuela de Medicina Veterinaria Facultad de Recursos Naturales Universidad Católica de Temuco Temuco Chile Laboratory of Molecular and Cellular Neurobiology Department of Molecular and Cellular Neurobiology Neurobiology Institute Campus Juriquilla-Querétaro Universidad Nacional Autónoma de México Mexico City Mexico

In Chile elevated percentage of population have cardiovascular diseases, 70% of this populations is a hypertensive peoples. The Ruta graveolens (Ruta) is a medicinal plant used in different parts of the world with different therapeutics properties like dermatologic as far as anti-helmintic properties. We analyzed the vascular action measuring the tension to identify vasodilator effect of Ruta extract in norm-tense rat’s aorta incubated and measured in isolated organ bath, and evaluating the toxicity effect in CRL-1730 cell line, through enzymatic assay (MTT), confocal microscopy (propidium iodide stain) and flow cytometry (TUNEL assay), including extracellular reactive oxygen species (ROS) production through luminescence assay. The results show with DE50 29 ± 0.1 μg/mL evidenced vasodilatation, partially endothelium-depend. The cytotoxicity showed with DE50 304.6 ± 2 μg/mL in enzymatic assay (MTT) while evidenced membrane permeability in high concentrations (1500 μg/mL), DNA fragmentation in absence of oxidative stress in only observed when high concentrations of Ruta are used over the cell culture. The vasodilatation activity is executed in subtoxic concentration and partially endothelium-depend without permeability effect in the membrane and deterioration of the cells viability suggesting a complex effect of Ruta preparation in the regulation of vascular tone.

关键词： Vasodilatation Ruta graveolens Toxicity Endothelium

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The Effect of Maize Grain Size on the Physicochemical Properties of Isolated Starch, Crude Maize Flour and Nixtamalized Maize Flours

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Agricultural Sciences 2016年第2期7卷 114-125页

作者： Lineth J. Vega-Rojas Margarita Contreras-Padilla Natalia Rincon-Londoño Alicia del Real López Rosa M. Lima-Garcia Natalia Palacios-Rojas Mario E. Rodriguez-Garcia Maestría en Ciencias Químico-Biológicas Facultad de Química Universidad Autónoma de Querétaro Querétaro México División de Investigación y Posgrado Facultad de Ingeniería Universidad Autónoma de Querétaro Cerro de las Campanas s/n Las Campanas Santiago de Querétaro Querétaro México Departamento de Nanotecnología Centro de Física Aplica y Tecnología Avanzada Universidad Nacional Autónoma de México Campus Juriquilla Querétaro México Posgrado en Ciencia e Ingeniería de Materiales Centro de Física Aplica y Tecnología Avanzada Universidad Nacional Autónoma de México Campus Juriquilla Querétaro México International Maize and Wheat Improvement Center (CIMMYT) Km 45 Carretera México-Veracruz Texcoco México Licenciatura en Ingeniería Física Facultad de Ingeniería Universidad Autónoma de Querétaro Querétaro México

Usually, the maize cob is formed by grains of medium size. However, the extremes have larger or smaller size grains. The objective of this study was to investigate the influence of grain size from the same hybrid on the physicochemical properties of isolated starch, crude maize flours and nixtamalized maize flours. Two hybrids, one from CIMMyT-Mexico called IMIC-254 and one commercial sample from Monsanto (Puma) were studied. The isolated starch granules from small, medium, and large grains exhibit the same size and distribution. The grain size has influence in the determination of cooking and steeping times;small grains reach these parameters faster than medium and large ones. The hardness of the grain size for both hybrids does not showed statistical differences between them. The starch from small, medium and large grains is mainly composed of amylopectin;this result is confirmed by X-ray diffraction and Megazine analysis. The apparent viscosity of the isolated starches of small grains showed statistically significant higher peak values. According to these results, it is possible to use small, medium, and large grains to obtain products with the same physicochemical properties, by adjusting the cooking and steeping times and Ca2+ content.

关键词： Maize Grain Size Nixtamalization Starch Rheological Properties

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Influence of Geological Factor on Indoor Radon Concentrations in Dwelling of Queretaro,Mexico

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Open Journal of Geology 2014年第12期4卷 627-635页

作者： Rocio García Martínez Anatoliy Kotsarenko Roman Pérez Enriquez Jose Antonio López Cruz Abeyro Svetlana Koshevaya Jesús Efrén Ospina Norena Centro de Ciencias de la Atmósfera Universidad Nacional Autónoma de MéxicoCiudad UniversitariaMéxico CityMéxico Universidad Autónoma del Carmen(UNACAR) Facultad de IngenieríaCiudad del CarmenMéxico Centro de Geociencias Universidad Nacional Autónoma de MéxicoCampus JuriquillaQuerétaroMéxico CIICAp Autonomous University of State Morelos(UAEM)CuernavacaMéxico Programa de Investigación de Cambio Climático Universidad Nacional Autónoma de MéxicoCiudad UniversitariaMéxico CityMéxico

In this study, radon-222 concentrations were measured within 34 houses distributed in the northern, southern, and central areas of the city of Querétaro in 2007. The objective of this study was to establish the spatial distribution of radon with respect to geological faults and its relation to certain environmental variables. For each sampling site, the radon-222 concentration was analyzed as a function of various climate variables, relative humidity, temperature, and atmospheric pressure, in addition to the ventilation of the house and distance of each site from any geological faults in the area. A multivariate statistical technique was used to analyze these variables based on two components. For component 1, the relative humidity and temperature had the greatest weight, 0.677 and 0.492, respectively, while for component 2, the greatest weights corresponded to radon and the temperature with 0.693 and 0.609, respectively. The average radon concentration across the entire sampling period was 38.92 Bq/m3, the minimum detected value was 6.01 Bq/m3?for site 91GAG0607, and the maximum detected value was 225.95 Bq/m3?for site 91CAM20907. This last value is outside the standards permitted by the Environmental Protection Agency of the United Stated, which is 148 Bq/m3?for indoor environments. With respect to geological faults and their relationship to radon-222, the concentrations for the sampling sites had no relationship to the closeness or distance to these faults.

关键词： Indoor Radon Geology Building Characteristics and Seasonal Variations

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Canopy Storage Implications on Interception Loss Modeling

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American Journal of Plant Sciences 2014年第20期5卷 3032-3048页

作者： Cesar Véliz-Chávez Carlos Alberto Mastachi-Loza Enrique González-Sosa Rocio Becerril-Pina Norma Maricela Ramos-Salinas Facultad de Ingenieria Centro Universitario S/NCerro de las CampanasSantiago de QuerétaroUniversidad Autonoma de QuerétaroQuerétaroMéxico Centro Interamericano de Recursos del Agua Facultad de Ingeniería Cerro de CoatepecCiudad UniversitariaUniversidad Autónoma del Estado de México TolucaToluca de LerdoMéxico Departamento de Tecnología Ciencia Arte y Humanidades Blvd Villas del Meson No.1000 col.Provincia JuriquillaSantiago de QuerétaroUniversidad del Valle de México Campus QuerétaroQuerétaroMéxico Division de Estudios de Posgrado Facultad de Contabilidad y AdministracionUniversidad Autonoma de QuerétaroCerro de las Campanas S/N CentroQuerétaroMéxico

A rainfall interception methodology was implemented in a deciduous Ficus benjamina (L.) tree to evaluate the interception loss, as well as the dynamics on canopy storage capacity (S) and free through fall (ρ). Measurements of gross precipitation (Pg), through fall and meteorological data were recorded every 5 minutes. Nineteen individual storms from summer to autumn 2005, and twenty one in spring to autumn, 2006 were analyzed. For the studied period, 151.59 mm and 203.35 mm of rainfall occurred on 2005 and 2006 respectively. Canopy interception was 59.46% and 70.98% of Pg for the first and second year. Throughfall data recorded during 2005 were ?38.14% (of Pg) and 27.21% (of Pg) for 2006. The throughfall and gross precipitation relationship yielded S = 1.50 mm for the 2005 data. In 2006 storms were analyzed in detail, where ρ and S varied in a range from 0.10 to 0.64 and from 1.00 to 2.03 mm, respectively. Moreover, application of the Rutter and Gash models with two years of rainfall data (2005-2006) from the study area indicated an underestimation and overestimation of 69% and 88%, respectively. The slightly best prediction of the interception loss was obtained with the Gash model. Yet S and ρ change significantly due to wind speed, temperature, rainfall intensity and seasonal vegetation development.

关键词： Interception Storage Capacity Throughfall Gash Model

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结肠直肠癌患者血清泌乳素与存活率的负相关关系:手术前放疗的影响

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世界核心医学期刊文摘（胃肠病学分册） 2006年第6期2卷 8-8页

作者： De La Barrera M.G. Trejo B. Luna-Pérez P. C. Clapp 陈云茹 Instituto de Neurobiologa Universidad Nacional Autónoma de México Campus UNAM-Juriquilla Km 15 Carretera Qro-SLP Querétaro Qro. 76230 Mexico Dr.

Prolactin (PRL) is a pleiotropic hormone associated with the progression of various cancers, including colorectal cancer (CRC). Here we investigate whether the association of serum PRL concentration and survival is affected by tumor location and preoperative radiotherapy (PRERT) in patients with CRC cancer. Serum PRL was determined in 82 CRC patients without previous treatment. Patients with PRL concentrations at and above the 75th percentile (high PRL) or below this level (low PRL), had a significant correlation with overall survival determined using the Kaplan-Meier method. In colon cancer, there was an increased risk of mortality when PRL values were at and above the highest quartile (22%vs. 73%; P = 0.01). In contrast, in rectal cancer, high PRL values were associated with a significant overall survival advantage (88%vs. 44%; P = 0.05), which became more significant (100%vs. 34%; P = 0.005) when only rectal cancer patients receiving PRERT were compared. These findings suggest that tumor location and adjuvant radiotherapy influence the association between circulating PRL and survival in CRC.

关键词：直肠癌患者血清泌乳素结肠直肠癌手术前放疗存活率负相关肿瘤部位辅助性放疗

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