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Behavior of Arsenic and Fluoride Concentration in Guadiana Valley Aquifer of Durango, Mexico

Journal of Environmental Protection 2013年第12期4卷 14-20页

作者： maría adriana martínez-prado maría Elena Pérez-López Ignacio Villanueva-Fierro Cecilia Corazón González-Nevarez Chemical Engineering Department Technological Institute of Durango (ITD) Durango Mexico National Polytechnic Institute Interdisciplinary Research Center for Regional Integral Development at Durango (IPN-CIIDIR-DGO) Durango Mexico

Fluorine (F) and arsenic (As) are inorganic elements present in the subsurface depending on the geology of the region. These compounds are found in high concentrations in the underground strata of Guadiana Valley of Durango affecting water quality for human consumption (NOM-127-SSA-1994). In the present research the main objective was to assess the behavior in time and space of fluoride (F-) and arsenic concentration, from 1996 to date, in the groundwater of the city of Durango and some wells of the rural area as a reference. The highest concentration of arsenic was found in a rural well, Colonia Hidalgo (0.149 mg/L or ppm), 6 times the maximum permissible limit (MPL);within the city well 54 located in the western sector had the highest value (0.076 ppm), 3 times the MPL, 67% of the wells in the city and 60% of the Guadiana Valley had levels that exceeded the MPL (0.025 ppm), the concentration in the city ranged from 0.009 to 0.149 ppm and from 0.08 to 0.15 ppm for the rural zone. With respect to F-, the highest value was also found in the Colonia Hidalgo well (17.8 mg/L), 12 times the MPL;within the city the highest value was recorded in well 16 in the eastern sector with 7.6 ppm (5 times the MPL) 97% of the wells in the city and 100% of the wells in the Guadiana Valley rural area had concentrations greater than MPL (1.5 ppm), the concentration in the city ranged from 1.1 to 7.6 ppm, while in the Guadiana Valley from 1.7 to 17.8 ppm. Statistical analysis showed no significant difference for fluoride concentration over time (1996-2013);whereas the concentration of arsenic decreased, probably due to the degree of precision required for such small concentrations in groundwater and different analysts ran the samples.

关键词： Aquifer Arsenic Fluoride Groundwater Quality Guadiana Valley

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Concentration of Fluoride and Arsenic in Bottled Drinking Water in Durango City, Mexico

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Journal of Environmental Protection 2013年第12期4卷 8-13页

作者： maría adriana martínez-prado maría Elena Pérez-López maría Guadalupe Vicencio-de la Rosa Cecilia Corazón González-Nevarez Chemical Engineering Department Technological Institute of Durango (ITD) Durango Mexico National Polytechnic Institute Interdisciplinary Research Center for Regional Integral Development at Durango (IPN-CIIDIR-DGO) Durango Mexico

Arsenic and fluoride are elements known to cause human health problems and it has been documented that both elements are found in high concentrations in the Guadiana Valley aquifer, in the state of Durango, Mexico. Since underground water is the source for potable water bottling companies commercialized in Durango City;such high concentrations reduced the quality of bottled water for human consumption according to NOM-041-SSA1-1993. Legislation establishes a maximum permissible limit (MPL) of 0.7 mg/L for fluoride and 0.025 mg/L for arsenic. In this research the main objective was to evaluate the quality of bottled water expended in Durango City with respect to the well from which water is extracted. Findings showed that the highest fluoride concentration was 5.86 mg/L (8.4 times MPL), with 100% of sampled brands exceeding the MPL (range: 1.09 to 5.86 mg/L). On the other hand, for arsenic, the highest concentration was 0.076 mg/L (threefold), with 38% exceeding the MPL (range: 0.001 to 0.076 ppm). Statistical analysis showed significant differences only for fluoride, according to Fisher LSD (Least Significant Difference) test, with an F value of 14.5 at a p value of 0.0005. According to the comparison between the quantified concentrations in bottled water and groundwater, it was found that groundwater was subjected to treatment;however, although a significant decrease in fluoride and arsenic concentration was observed, the removal processes used were not efficient to meet set standards.

关键词： Arsenic Bottled Water Quality Fluoride Guadiana Valley Aquifer Groundwater

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Global evolution of Equidae and Gomphotheriidae from South America

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Integrative Zoology 2014年第4期9卷 434-443页

作者： JoséL.prado maría T.ALBERDI INCUAPA CONICET-UNICENNational University of Central Buenos Aires ProvinceOlavarríaArgentina Department of Paleobiology Museo Nacional de Ciencias NaturalesCSICMadridSpain

The contemporary South American mammalian communities were determined by the emergence of the Isthmus of Panama and by the profound climatic oscillations during the *** and gomphotheres were 2 very conspicuous groups of immigrant mammals from North America that arrived in South America during the *** present study compiles updated data on the phylogeny,systematics and ecology of both groups in South *** horses in South America are represented by 2 genera,Hippidion and Equus,as are the gomphotheres,represented by Cuvieronius and *** genera of horses include small(Hippidion devillei,***,*** and ***)and large forms(Equus neogeus and ***),which dispersed into South America using 2 different *** possible model for this dispersion indicates that the small forms used the Andes corridor,while larger horses dispersed through the eastern route and through some coastal *** the case of gomphotheres,Cuvieronius and Stegomastodon reached South America in 2 independent dispersal events,and Cuvieronius dispersed across the Andean corridor,while large Stegomastodon spread along the eastern *** and gomphotheres present values ofδ^(13)C from woodlands to C4 grass*** present lower values ofδ^(13)C than Equus in the late Pleistocene,whereas the gomphotheres diverge from value ofδ^(18)O,reflecting that Cuvieronius inhabited the Andean corridor and Stegomastodon dispersed through eastern *** gomphothere and horse species recorded in South America became extinct around the time that humans arrived.

关键词： Equidae Gomphotheriidae Plio-Pleistocene South America

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Development of Aircraft Maintenance Glossaries in Higher Education:Exploring Methodological Paths to Corpus-Driven Analysis of Key Keywords

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中国科技术语 2025年第1期27卷 83-93页

作者： Malila prado Daniela TERENZI Diego BRITO BNU-HKBU United International College Zhuhai 519087 Federal Institute of Education Science and Technology of São PauloSão Carlos 13.565-820

This paper presents a project aimed at developing a trilingual visual dictionary for aircraft maintenance professionals and *** project addresses the growing demand for accurate communication and technical terminology in the aviation industry,particularly in Brazil and *** study employs a corpus-driven approach,analyzing a large corpus of aircraft maintenance manuals to extract key technical terms and their *** specialized subcorpora and a comparative analysis,this paper demonstrates challenges and solutions into the identification of high-frequency keywords and explores their contextual use in aviation documentation,emphasizing the need for clear and accurate technical *** incorporating these findings into a trilingual visual dictionary,the project aims to enhance the understanding and usage of aviation terminology.

关键词： aircraft maintenance corpus keyword extraction

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Precipitation Kinetics on a Nb-V Microalloyed Steel

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Journal of Iron and Steel Research International 2011年第S1期18卷 148-153页

作者： Cartaya Elio Armando Cabrera José maría prado José Manuel Departamento de Ciencia de Materiales e Ingeniería Metalúrgica ETSEIBUniversidad Politécnica de Catalua Av.Diagonal 64708028 BarcelonaSpain Departamento de Manufactura y Materiales Facultad de Ingeniería MecánicaUniversidad de OrienteSantiago de CubaCuba Fundación CTM Centro Tecnológico Av.Bases de Manresa 108242 ManresaSpain

The precipitation kinetics in a low carbon high strength low alloy (HSLA) steel,microalloyed with V+Nb has been studied by using the stress relaxation *** technique was carried out in a dynamic dilatometer and allows to determine the onset and finishing precipitation times in hot deformed *** evolution of the precipitates was also observed using field emission scanning electron microscopy (FESEM) on samples quenched at different times at given *** is completed with the predictions by the thermodynamic software FactSage to identify stable precipitate phases under equilibrium *** confirm the feasibility of the stress relaxation technique as an efficient method for investigating precipitation kinetics.

关键词： stress relaxation microalloyed steels precipitation FESEM

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Strain Influence on the Precipitation Kinetic Nb-V Microalloyed HSLA Steel

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Journal of Iron and Steel Research International 2011年第S1期18卷 278-281页

作者： Cartaya Elio Armando Cabrera José maría prado José Manuel Departamento de Ciencia de Materiales e Ingeniería Metalúrgica ETSEIBUniversidad Politécnica de Catalu a Av.Diagonal 64708028 BarcelonaSpain Departamento de Manufactura y Materiales Facultad de Ingeniería MecánicaUniversidad de Oriente90400 Santiago de CubaCuba Fundación CTM Centro Tecnológico Av.Bases de Manresa 108242 ManresaSpain

The strain induced effect on the precipitation kinetics of a high strength low alloy (HSLA) steel microalloyed with Nb-V was *** stress relaxation method was employed to determine the dependence of the precipitation-time-temperature curves (PTT) on previous *** tests were performed over a temperature range of 850 to 1150 oC at a constant strain rate of 0.1 s-1 at three deformation levels,namely 5,15 and 25 *** emission scanning electron microscopy (FESEM) was used to study the progress of precipitation on samples obtained by interrupted relaxation test at different *** display the acceleration kinetics at increasing *** models are discussed and compared with the present experimental results.

关键词： strain induced precipitation kinetic HSLA stress relaxation PTT

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The relation between ductility at high temperature and solid solution in Mg alloys

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Journal of Magnesium and Alloys 2022年第1期10卷 241-256页

作者： D.F.Shi C.M.Cepeda-Jiménez M.T.Pérez-prado IM DEA Materials Institute C/Eric Ka ridel228906 GetafeMadridSpain Department of Materials Science Polytechnic University of Madrid/Universidad Politecnica de MadridE.T.S.de Ingenieros de Caminos28040MadridSpain Department of Physical Metallurgy CENIMCSICAv.Gregorio del Amo 828040 MadridSpain

This work investigates the effect of solid solution on ductility and on the activation of individual deformation mechanisms at moderate temperatures and at quasi-static strain rates in Mg-Zn and Mg-Al alloys. With that aim, four solid solution Mg-Zn and Mg-Al binary alloy ingots containing 1 and 2 wt.% solute atoms were subjected to hot rolling and subsequent annealing to generate polycrystals with similar average grain size and basal-type texture for each composition. The activity of the different slip systems after tensile testing at 150°C and at 250°C was evaluated in pure Mg and in the alloys by EBSD-assisted slip trace analysis. In addition, segregation of Zn and Al atoms at grain boundaries during the thermo-mechanical processing was characterized by HAADF-STEM and EDX. It was found that while the addition of Al and Zn atoms to pure Mg does not lead to major changes in the mechanical strength at the investigated temperatures, it does enhance ductility significantly, especially at 250℃. Our results show that this increase in ductility cannot be attributed to a higher activation of non-basal systems in the alloys, as reported earlier, as the incidence of non-basal systems is indeed considerably higher in pure Mg. This work suggests, on the contrary, that the ductility increase may be attributed to the presence of a more homogenous basal activity in the alloys due to a lower degree of orientation clustering, to grain boundary solute segregation, and to a higher slip diffusivity at grain interiors.

关键词： Magnesium Solute segregation Slip trace analysis Ductility Deformation mechanisms

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Potential of Bamboo Species Guadua trinii and Guadua angustifolia for Nanocellulose Production

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Journal of Renewable Materials 2024年第9期12卷 1541-1555页

作者： Agatha E.R.prado Gárate Fernando E.Felissia maría Cristina Area Teresa Suirezs maría Evangelina Vallejos Círculo de Investigación del Bambú Universidad Nacional Agraria La Molina(UNALM)Lima15026Perú Instituto de Materiales de Misiones(IMAM) Universidad Nacional de Misiones(UNaM)Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET)Facultad de Ciencias ExactasQuímicas y Naturales(FCEQYN)Programa de Celulosa y Papel(PROCyP)Posadas3300Argentina Instituto de Materiales de Misiones(IMAM) Universidad Nacional de Misiones(UNaM)Consejo Nacional de Investigaciones Científicas y Técnicas(CONICET)Facultad de Ciencias Forestales(FCF)Eldorado3380Argentina

Non-traditional lignocellulosic materials are a significant resource for producing high-value products,including *** work studied the nanocellulose obtention from chemical pulps of the two fast-growing bamboo species,Guadua trinii,and Guadua *** pulps were produced by soda-anthraquinone(S)pulping from both autohydrolysis-pretreated(H)and unpretreated bamboo ***-pretreated(SHP)and unpretreated soda-anthraquinone(AQ)(SP)pulps were characterized by yield,Kappa number,alpha,beta,and gamma cellulose,degree of polymerization,water retention value,and *** nanocellulose was produced by a sequential chemical oxidation treatment(2,2,6,6-tetramethylpiperidine-1-oxyl,TEMPO reagent)and mechanical *** was characterized by carboxylic group content and *** results revealed that autohydrolysis pretreatment resulted in a higher hemicelluloses extraction in *** contrast,the pulping yield of unpretreated samples was higher for ***,and the soda-AQ pulps from this species exhibited better delignification than the autohydrolysis-pretreated *** crystallinity index values of the obtained pulps were high(>80%),and the alpha-cellulose contents were *** viscosities of the aqueous nanocellulose suspensions were higher for the nanocellulose solutions obtained from the unpretreated soda-AQ ***,nanocellulose from *** unpretreated soda-AQ pulps had a higher rate of carboxylic *** results of this work are significant in assessing the potential of both bamboo species as a source of high-value products within the biorefinery framework because the viscosities of the aqueous nanocellulose suspensions depend on the size and shape of *** has significant importance for industrial unit operations and potential applications.

关键词： Natural fiber Guadua angustifolia Guadua trinii soda-anthraquinone pulp nanocellulose

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Expanding the Boundaries of the Chemical Space of DNA Methyltransferase 1 Modulators

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Computational Molecular Bioscience 2024年第1期14卷 1-16页

作者： Massyel S. martínez-Cortés Diana L. prado-Romero José L. Medina-Franco DIFACQUIM Research Group Department of Pharmacy School of Chemistry Universidad Nacional Autónoma de México Avenida Universidad 3000 Mexico City México

DNA methyltransferase 1 (DNMT1), one of the main epigenetic targets, is involved in the duplication of the DNA methylation pattern during replication, and it is essential for proper mammalian development. Small molecule DNMT1 modulators are attractive for biochemical epigenetic studies and have the potential to become drugs. So far, more than five hundred small molecules have been reported as DNMT1 inhibitors. However, only a limited number of DNMT1 activators have been disclosed because, at least in part, DNMT1 activators are typically regarded as negative data in virtual screening campaigns or optimization projects. This manuscript aims to report the chemical structures and biological activity of small molecules that increase the enzymatic activity of DNMT1. Results of the biochemical experimental assays are discussed. It was found that small molecule activators have a large variety of chemical scaffolds but share pharmacophore features. Visual analysis of the chemical space and multiverse based on molecular fingertips supported that activators are structurally diverse. This is the first report of eight small molecules that increase the enzymatic activity of DNMT1 by more than 400% in an enzymatic-based assay. The outcome warrants further investigation of the epigenetic activity of the compounds in a counter-screen assay, e.g., cell-based and in vivo context.

关键词： Chemical Multiverse Chemoinformatics Epigenetics Pharmacophore Hypothesis Small Molecules

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How nerve-sparing technique has been applied to radiotherapy？

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Asian Journal of Andrology 2016年第6期18卷 898-899页

作者： Kris prado Arnold I Chin Department of Urology UCLA Los Angeles CA 90095 USA Broad Stem Cell Research Center UCLA Los Angeles CA 90095 USA Jonsson Comprehensive Cancer Center UCLA Los Angeles CA 90095 USA

The introduction of nerve-sparing technique is one of the most significantadvances in the surgical treatment of prostate cancer and heralded a shift from a curing cancer at all-cost model to a curing cancer and preser... 详细信息

关键词： @@

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