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Nano to micro size transition of hydroxyapatite in porcine bone during heat treatment with low heating rates

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Progress in Natural Science:Materials International 2020年第4期30卷 494-501页

作者： Angélica M.Castillo-Paz Sandra M.Londo?o-Restrepo Liliana Tirado-Mejía M.A.Mondragón mario E.rodríguez-García Grupo de Optoelectrónica Instituto Interdisciplinario de las Ciencias Universidad del Quindío Centro de Investigación y de Estudios Avanzados del IPN Departamento de Nanotecnología Centro de Física Aplicada y Tecnología Avanzada Universidad Nacional Autónoma de México Campus Juriquilla

This work focuses on the changes of raw hydroxyapatite obtained from porcine bones during heat treatment with heating rates of 2.5 and 5.0 °C/min between 600 °C and 1100 °C. High-Resolution transmission electron microscopy(HR-TEM) images showed that raw hydroxyapatite was formed by high-ordered nanometric platelet crystals with a length of around 18 nm and width around 7 nm. High-Resolution scanning electron microscopy(HR-SEM) images evidenced the coalescence phenomena during heating giving. It was found that the growth of the crystals and the transition from nano to a micro-size occurred at around 700 °C. And the changes in the full width at half maximum(FWHM) for the characteristic(002) plane of the X-ray diffraction patterns and the FWHM of the characteristic Raman band at 960 cm-1 for ν1 PO43-exhibited the transition from nano to a micro size, that was confirmed by HR-SEM images and the thermogravimetric(TG) analysis. The porosity of the BIOHAp changes from intra nanometric to intercrystalline.

关键词： Bone composition Hydroxyapatite nanoparticles Mineral composition Porosity formation Raman analysis

Temporal Evolution of Anodization Current of Porous Silicon Samples

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Materials Sciences and Applications 2013年第8期4卷 43-47页

作者： Adriana Gutiérrez Jairo Giraldo mario Enrique rodríguez-García Centro de Física Aplicada y Tecnología Avanzada Universidad Nacional Autónoma de México Querétaro México Departamento de Física Universidad Nacional de Colombia-Sede Bogotá Ciudad Universitaria Bogotá DC Colombia Departamento de Física Universidad Nacional de Colombia-Sede Bogotá Ciudad Universitaria Bogotá DC Colombia Departamento de Física Universidad Militar Nueva Granada Bogotá DC Colombia

Temporal evolution of the anodization current of porous silicon samples was studied by means of a model of resistances connected in series that represented the temporal changes of the substrate and of the interface between the substrate and the electrolyte during the porous sample formation process. The porous samples were obtained by means of photoelectrochemical etching of (100) n-type silicon wafers with different resistivity values, all in the range of 1 - 25 Wcm. The samples were formed at room temperature in an electrolytic bath composed by a mixture of hydrofluoric acid (48%) and ethanol having a composition ratio of 1:1 in volume under potentiostatic condition (10 V and 20 V) and an etching time of 2 minutes using back illumination provided by a laser beam with a wavelength of 808 nm.

关键词： Porous Silicon Electrochemical Etching Anodization Current

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

Electroencephalographic coherences during emotion identification task

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World Journal of Neuroscience 2012年第4期2卷 248-253页

作者： Erzsebet Marosi Holczberger Jorge Bernal Juan Silva Guillermina Yanez mario rodríguez Belen Prieto Vicente Guerrero National University of Mexico FES IztacalaNeurosciences DepartmentMexico CityMexico

Coherence, a measure of spectral similarity, may estimate cortical coupling between two EEG signals as a function of frequency. The coherence between EEG signals from different brain areas depends on the structural connection and functional coupling between two regions. The theory of hemispheric specialization proposes left hemisphere activation to positive emotions and right one to negative emotions. Other proposal is that right hemisphere activation occurs with emotional stimuli. In the present study EEG coherences were calculated during the presentation of the International Affective Pictures to 36 healthy male university students. The subjects’ task was to determine the valence of the stimuli. Base line recording were done with subjects observing the blank monitor. Our results showed higher coherences during the emotional condition. No differences between negative and positive emotions were obtained. Neutral pictures evoked the highest coherence values. These data suggest that coherences between functionally coupled brain areas do not reflect emotional recognition of the valence of stimuli, but they are internal indicators of different mental processes such as memory, mental effort and arousal. Our findings do not support the theory of hemispheric specialization, neither the theory of right hemisphere;rather they suggest a complex activation pattern that involves mostly frontal areas in connection with the entire cortex.

关键词： EEG Coherences Emotions of Positive and Negative Valence International Affective Pictures

In vitro Antibacterial Activity of Moringa oleifera Ethanolic Extract against Tomato Phytopathogenic Bacteria

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Phyton-International Journal of Experimental Botany 2021年第3期90卷 895-906页

作者： Roberto Arredondo-Valdés Francisco D.Hernández-Castillo mario Rocandio-rodríguez Julia C.Anguiano-Cabello Madai Rosas-Mejía Venancio Vanoye-Eligio Salvador Ordaz-Silva Imelda V.López-Sánchez Laura D.Carrazco-Peña Julio C.Chacón-Hernández Institute of Applied Ecology Universidad Autónoma de TamaulipasCiudad VictoriaTamaulipas87019México Parasitology Department Universidad Autónoma Agraria Antonio NarroSaltillo25315México Health Area Universidad La Salle SaltilloSaltillo25298México Faculty of Engineering and Business San Quintin Universidad Autónoma de Baja CaliforniaSan Quintín22930México

The tomato(Solanum lycopersicum L.)is one of the world’s most important vegetable ***,phytopathogenic bacteria affect the yield and quality of tomato cultivation,like Agrobacterium tumefeciens(At),Clavibacter michiganensis ***(Cmm),Pseudomonas syringae ***(Pst),Ralstonia solanacearum(Rs),and Xanthomonas axonopodis(Xa).Synthetic chemical products are used mostly on disease plant control,but overuse generates resistance to bacterial *** study aimed to evaluate the in vitro antibacterial activity of the ethanolic extract of Moringa oleifera *** against At,Cmm,Pst,Rs,and Xa,as well as information about this plant species’chemical *** activity against pathogens observed by microplate technique,phytochemical screening,and FTIR analysis revealed different bio-active compounds on ethanolic extracts with antibacterial *** growth inhibition rate ranged between 0.08%and 99.94%.The inhibitory concentration,IC50,required to inhibit 50%of At,Cmm,Pst,Rs,and Xa bacterial growth,was 276.67,350.48,277.85,351.49,and 283.22 mg/L,*** of phytopathogen bacteria’s growth increased as the concentrations of the extract also *** oleifera extract can be recommended as a potent bio-bactericide.

关键词： Biological control secondary metabolites tomato crop inhibitory concentration botanical extract

Genome-wide comparison inferred the origin and evolution of B-cell epitopes on the proteins of human influenza A virus

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Health 2012年第10期4卷 946-954页

作者： Edgar E. Lara-Ramírez Aldo Segura-Cabrera Ma. Isabel Salazar mario A. rodríguez-Pérez Xianwu Guo Centro de Biotecnología Genómica Instituto Politécnico Nacional Reynosa México Departamento de Inmunología Escuela Nacional de Ciencias Biológicas Unidad Profesional Lázaro Cárdenas Instituto Politécnico Nacional México

The novel strain H1N1 caused the outbreak of first pandemic influenza in 21 century. Now it is a common component of current seasonal influenza viruses. The recent transmission and plentiful genome sequences available provided a good opportunity to study the origin and evolution of epitopes on the proteins of human influenza virus. In the present study, the B-cell epitope compositions in the pandemic strains, circulating traditional seasonal strains, swine strains as well as highly virulent avian strain H5N1 were identified with the aid of the Immune Epitope DataBase (IEDB) and were compared at genomic level. A total of 14210 distinct sequences down-loaded from NCBI database were used for analysis. Some epitopes on proteins HA or NA, not conserved in recent seasonal strains, were found in 2009 pandemic strains but existed in the early human strains (1919-1935). The pandemic strain shared higher conserved epitopes with “bird flu” virus H5N1than classic human seasonal strains. The epitopes that could exist at common antigenic regions of HA protein are needed to further identify. The genetic exchanges between human and swine population by transmission was very active but the princepal side of the transmission could be from swine to human. These results provided valuable information on influenza A virus evolution and transmission by means of epitope analysis at genomic level.

关键词： Influenza A Virus H1N1 Pandemic Epitopes Genome Comparison

Synthesis of Amine Terminated Pegylated Iron Oxide Nanoparticles for Prospective Astrocytoma Resection Grade Improvement

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材料科学与工程（中英文A版） 2019年第1期9卷 25-37页

作者： Isaias Eduardo Hernández-Verdin María Luisa Martínez Alejandro Miranda-González Mónica Alicia Sierra del Río Oracio Serrano-Torres mario Avila-rodríguez Experimental neuro-oncology Groupe Hospitalier Pitié-SalpêtrièreParis 75013France Departamento de Ciencias e Ingeniería Universidad Iberoamericana LeónLeón 37238Mexico Departamento de Neurociencias Hospital Regional de Alta Especialidad del BajíoLeón 37660Mexico Departamento de Química División de Ciencias Naturales y ExactasCampus GuanajuatoUniversidad de GuanajuatoGuanajuato 36040Mexico

Having a survival rate to 5 years of only 3%,Glioblastoma’s(GBM)main treatment is surgical *** oxide nanoparticles have been proved to be a magnetic resonance imaging contrast agent and,if synthesized and tuned correctly,could be used to improve complete GBM *** this work monodisperse iron oxide nanoparticles were synthesized using thermal decomposition method,then a ligand exchange reaction with 3-aminopropyl trimethoxysilane(APS)was performed,following Pegylation of the particles using dicarboxylic acid PEG(PEG-diacid)and finally aminating with 2,2’-(ethylenedioxy)bis(ethylamine),last two by amide *** and DLS demonstrate monodispersity(log σ<0.2)and desired size range to penetrate the blood-brain barrier(BBB);FT-IR shows the reactions were executed correctly and finally stability in deionized water,0.07 M NaCl and PBS 1X,as a function of 0-30 days,was *** revealed the importance that the oleic acid/iron oleate molar ratio and the growth stage time represents for determining iron oxide nanoparticles’ size;as well as APS concentration and nucleation time influence on silica coating when performing the ligand exchange *** produced iron oxide nanoparticles exhibit stability and proper amine terminated groups which are needed to allow easy incorporation of Chlorotoxin,a 36-amino acid peptide that binds specifically to astrocytoma cells,and a fluorescent molecule,which enables real time visualization of the tumor during surgery.

关键词： Iron oxide nanoparticles silanization pegylation astrocytoma

Removal of carbofuran is not affected by co-application of chlorpyrifos in a coconut fiber/compost based biomixture after aging or pre-exposure

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Journal of Environmental Sciences 2016年第8期28卷 182-189页

作者： Juan Salvador Chin-Pampillo mario Masís-Mora Karla Ruiz-Hidalgo Elizabeth Carazo-Rojas Carlos E.rodríguez-rodríguez Research Center of Environmental Contamination (CICA) University of Costa Rica

Biomixtures constitute the biologically active part of biopurification systems（BPS）, which are used to treat pesticide-containing wastewater. The aim of this work was to determine whether co-application of chlorpyrifos（CLP） affects the removal of carbofuran（CFN）（both insecticide/nematicides） in a coconut fiber–compost–soil biomixture（FCS biomixture）, after aging or previous exposure to CFN. Removal of CFN and two of its transformation products（3-hydroxycarbofuran and 3-ketocarbofuran） was enhanced in pre-exposed biomixtures in comparison to aged biomixtures. The co-application of CLP did not affect CFN removal, which suggests that CLP does not inhibit microbial populations in charge of CFN *** to the removal behavior, mineralization of radiolabeled14C-pesticides showed higher mineralization rates of CFN in aged biomixtures（with respect to freshly prepared or pre-exposed biomixtures）. In the case of CLP, mineralization was favored in freshly prepared biomixtures, which could be ascribed to high sorption during aging and microbial inhibition by CFN in pre-exposure. Regardless of removal and mineralization results, toxicological assays revealed a steep decrease in the acute toxicity of the matrix on the microcrustacean Daphnia magna（over 97%） after 8 days of treatment of individual pesticides or the mixture CFN/*** suggest that FCS biomixtures are suitable to be used in BPS for the treatment of wastewater in fields where both pesticides are employed.

关键词： Biomixture Pesticide Mineralization Toxicity Biopurification system

Fungal contamination of stored automobile-fuels in a tropical environment

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Journal of Environmental Sciences 2010年第10期22卷 1595-1601页

作者： Carlos E.rodríguez-rodríguez Evelyn rodríguez Rigoberto Blanco Ivannia Cordero Daniel Segura Research Center in Tropical Diseases and Laboratory of Research in Anaerobic Bacteriology Faculty of MicrobiologyUniversity of Costa Rica Department of Chemical Engineering School of EngineeringAutonomous University of Barcelona Research Center in Electrochemistry and Chemical Energy University of Costa Rica

Because of the lack of reports, the base levels of microbial contamination on stored fuels are unknown in tropical regions and it is unclear whether these levels have some influence on fuel quality parameters. Therefore, fungal quality in automobile fuels stored across Costa Rican territory was evaluated during two years according to the standard ASTM D6974-04. For a total of 96 samples, counts and identification of molds and yeasts were performed on regular gas, premium gas and diesel taken from the bottom and superior part of the container tanks. The highest contamination was found on the bottom of the tanks, where an aqueous phase was usually identified, showing populations over the ones present in the hydrocarbon itself （up to 108 CFU/L）. Diesel was the most contaminated fuel （up to 107 CFO/L）; however, an alteration on the physicochemical parameters was not observed in any kind of fuel. Seventy-five mold strains were isolated, Penicillium sp. being the most common genus （45.8% of the samples）, and ten yeast strains, from the genera Candida sp. and Rhodotorula sp. Four of the yeasts were able to grow on diesel as the sole carbon source, at concentrations ranging from 0.5% to 25%. Increasing the frequency of tank cleaning, adding antimicrobial agents and monitoring microbial populations are recommended strategies to improve microbial quality of stored fuels.

关键词： fuel microbial contamination biodegradation molds yeasts