27 research outputs found

    Unveiling the origin of oxygen atomic impurities in Au nanowires

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    The appearance of unusually large Au-Au bond distances in linear atomic chains (LACs) of Au nanowires is commonly attributed to the presence of atomic impurities. However, the origin of those contaminants is unknown. We present a study based on density functional theory calculations using quasistatic (T=0) and finite-temperature ab initio molecular-dynamics simulations of a possible route for the formation of atomic impurities in Au nanowires. This process starts with the adsorption of an O2 molecule followed by a CO molecule on Au LACs, leading to the formation of an intermediate O2CO complex. Upon thermal activation at finite temperatures, the complex is able to proceed to oxidation forming a CO2 molecule and leaving an atomic O impurity in the Au LAC

    Germinación Y Crecimiento En Vivero Y En Campo De Zaya (Amoreuxia palmatifida DC.), Una Especie Nativa Amenazada En México

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    The food needs by the human population is increasing; In that sense, having a new crop can contribute to ameliorate the demand for food. The zaya (Amoreuxia palmatifida DC.) has been used as food both before and after the arrival of the European settlers in several states of northwest Mexico and southwestern United States. Over a hundred years ago there are authors recommending the zaya as a native plant with potential to be cultivated, being one of the problems to overcome the difficulty of its seeds to germinate. The study objectives were to evaluate germination treatments of zaya seeds and measure plantula grow under two systems. It was found that seeds physically scarified by sanding were those that germinated (73%; p <0.0001), compared to treatments control, of soaking for 24 hours and addition, of boiling water, were does not germinate any seed. The results of zaya growth were greater (p <0.0001), for plants in open field under drip irrigation, compared to the plants planted in pots under shadehouse, for all variables evaluated. The results obtained in this work, about the germination and growing of zaya, can be used to multiply their propagules and restore natural populations affected in northwest of Mexico. It is necessary to continue research on agronomic aspects of the zaya cultivation, a plant with great potential for both human and animal feeding, ornamental, and possibly medicinal use

    Perspectivas del cultivo de la saya (Amoreuxia spp.) en el noroeste de México como nuevo producto agronómico.

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    In the past, the inhabitants of northwestern Mexico benefited from the saya plant (several species from the Amoreuxia genus), taking advantage of it for both food and medicinal purposes, and subsequently European colonizers utilized it as food, when faced with famine. Currently, some of these species have shown a decline in populations, so they are now considered to be in the NOM 059, 2010 risk category of the Ministry of the Environment and Natural Resources. Recent endeavors have provided knowledge concerning how to propagate this plant under agricultural conditions. In this work, cultivation of saya (A. palmatifida) crop was evaluated over two consecutive years, in order to compare productivity during the first year with plants obtained from direct germination of seeds under agricultural conditions, with those produced the second year from tuberous root regrowth. Greater plant productivity was found in the second year evaluation (p<0.0001), in terms of plant growth, seed production and weight of tuberous roots. In the future, it may be possible for some species from the Amoreuxia genus to have very positive social impact, if multiplication techniques for this species, as described in this work are applied, in order to rehabilitate this plant in grazing lands of northwestern Mexico and even to generate new plants.En el pasado los pobladores del noroeste de México se beneficiaron de la planta saya (varias especies del género Amoreuxia), aprovechándola tanto con fines alimenticios como medicinales, luego los colonizadores europeos la aprovecharon como alimento ante hambrunas. Actualmente algunas de estas especies presentan disminución en sus poblaciones, por lo cual han sido consideradas en categorías de riesgo de la NOM 059 de la Secretaría del Medio Ambiente y Recursos Naturales en el año 2010. Esfuerzos recientes han aportado conocimiento sobre formas de multiplicación de la planta bajo condiciones agrícolas. En este trabajo se evaluó el cultivo de saya (A. palmatifida) durante dos años consecutivos, para comparar la productividad del primer año de plantas obtenidas de germinación directa de semillas en condiciones agrícolas, con la productividad del segundo año a partir del rebrote las raíces tuberosas. Se encontró una mayor productividad de las plantas en el segundo año de evaluación (p < 0.0001), tanto en crecimiento de la planta, producción de semillas y peso de las raíces tuberosas. El futuro impacto social de algunas especies del género Amoreuxia puede ser muy positivo aplicando las técnicas de multiplicación de esta especie, descritas en este trabajo, para recuperar esta planta en los terrenos de agostadero del noroeste de México e incluso para generar nuevos cultivos

    Manejo de los materiales plásticos reciclados y mejoramiento de sus propiedades

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    El presente artículo hace un estudio de lo que es un material plástico reciclado y susaplicaciones. Se inicia con una revisión del concepto de material plástico, sus propie-dades, aspectos y aplicaciones. Adicionalmente, se listan los materiales plásticos másempleados comercialmente y los que se están desarrollando con el fin de reducir elimpacto en el medio ambiente. Posteriormente se hace una revisión de las metodologíasexistentes tanto a nivel mecánico como químico para el procesamiento de los materialesplásticos reciclados, con el fin de obtener objetos de material reciclado, combustibles uotro tipo de plásticos. Finalmente, se hace el planteamiento de una alternativa para elmejoramiento de su calidad

    Megaproyectos urbanos y productivos. Impactos socio-territoriales

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    El desarrollo de megaproyectos productivos trae consigo oportunidades para el crecimiento económico, la generación de empleos y el desarrollo regional. No obstante, en la actualidad, los grandes temas como la expansión urbana, el desarrollo industrial, las cementeras, la minería, el uso intensivo del agua y demás recursos naturales, preocupan a las comunidades por los impactos generados y porque en lo general, no consideran la racionalidad y responsabilidad ambiental y social hacia el entorno. En este contexto son diversos los estudios científicos que, en el marco de la política de económica imperante, intentan posicionarse como alternativas a proyectos económicos que confrontan los intereses particulares y comunitarios y que afectan la salud humana y ambiental. Megaproyectos urbanos y productivos. Impactos socio-territoriales, reúne veinticinco textos académicos sobre las afectaciones que éstos emprendimientos tienen para la sociedad y el entorno. Los temas expuestos recogen experiencias en el desarrollo urbano, industrial, turístico, portuario y aeroportuario, entre otros. Así mismo se retoman temas como la ética, la dialéctica, la política y la economía y su relación en el emprendimiento de megaproyectos. La búsqueda de esquemas productivos racionales y responsables con el entorno, que reivindiquen el derecho de las comunidades a un medio ambiente sano, a la preservación del territorio y sus recursos y de las formas de vida tradicionales, son los referentes para la realización del presente libro. Como elemento central se concibe el territorio como contenedor de identidad y vida, siendo preocupación y tema de estudio de la comunidad académica, las organizaciones de la sociedad civil y las redes de activistas organizados.UAEM, CONACyT, se

    Clonal chromosomal mosaicism and loss of chromosome Y in elderly men increase vulnerability for SARS-CoV-2

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    The pandemic caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2, COVID-19) had an estimated overall case fatality ratio of 1.38% (pre-vaccination), being 53% higher in males and increasing exponentially with age. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, we found 133 cases (1.42%) with detectable clonal mosaicism for chromosome alterations (mCA) and 226 males (5.08%) with acquired loss of chromosome Y (LOY). Individuals with clonal mosaic events (mCA and/or LOY) showed a 54% increase in the risk of COVID-19 lethality. LOY is associated with transcriptomic biomarkers of immune dysfunction, pro-coagulation activity and cardiovascular risk. Interferon-induced genes involved in the initial immune response to SARS-CoV-2 are also down-regulated in LOY. Thus, mCA and LOY underlie at least part of the sex-biased severity and mortality of COVID-19 in aging patients. Given its potential therapeutic and prognostic relevance, evaluation of clonal mosaicism should be implemented as biomarker of COVID-19 severity in elderly people. Among 9578 individuals diagnosed with COVID-19 in the SCOURGE study, individuals with clonal mosaic events (clonal mosaicism for chromosome alterations and/or loss of chromosome Y) showed an increased risk of COVID-19 lethality

    Prevalence, associated factors and outcomes of pressure injuries in adult intensive care unit patients: the DecubICUs study

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    Funder: European Society of Intensive Care Medicine; doi: http://dx.doi.org/10.13039/501100013347Funder: Flemish Society for Critical Care NursesAbstract: Purpose: Intensive care unit (ICU) patients are particularly susceptible to developing pressure injuries. Epidemiologic data is however unavailable. We aimed to provide an international picture of the extent of pressure injuries and factors associated with ICU-acquired pressure injuries in adult ICU patients. Methods: International 1-day point-prevalence study; follow-up for outcome assessment until hospital discharge (maximum 12 weeks). Factors associated with ICU-acquired pressure injury and hospital mortality were assessed by generalised linear mixed-effects regression analysis. Results: Data from 13,254 patients in 1117 ICUs (90 countries) revealed 6747 pressure injuries; 3997 (59.2%) were ICU-acquired. Overall prevalence was 26.6% (95% confidence interval [CI] 25.9–27.3). ICU-acquired prevalence was 16.2% (95% CI 15.6–16.8). Sacrum (37%) and heels (19.5%) were most affected. Factors independently associated with ICU-acquired pressure injuries were older age, male sex, being underweight, emergency surgery, higher Simplified Acute Physiology Score II, Braden score 3 days, comorbidities (chronic obstructive pulmonary disease, immunodeficiency), organ support (renal replacement, mechanical ventilation on ICU admission), and being in a low or lower-middle income-economy. Gradually increasing associations with mortality were identified for increasing severity of pressure injury: stage I (odds ratio [OR] 1.5; 95% CI 1.2–1.8), stage II (OR 1.6; 95% CI 1.4–1.9), and stage III or worse (OR 2.8; 95% CI 2.3–3.3). Conclusion: Pressure injuries are common in adult ICU patients. ICU-acquired pressure injuries are associated with mainly intrinsic factors and mortality. Optimal care standards, increased awareness, appropriate resource allocation, and further research into optimal prevention are pivotal to tackle this important patient safety threat
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