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Metal oxyhydroxides-carbon hybrid adsorbents to remove priority pollutants from water: fluoride and arsenic
Get PDF"La contaminación del agua por fluoruros (F- ) y arsénico (As) es un problema de importancia mundial, ya que el agua subterránea de varios países excede los límites permisibles establecidos por la Organización Mundial de la Salud (OMS), lo cual representa un riesgo para la salud humana. Por esta razón, el F- y el As se consideran contaminantes prioritarios que determinan la calidad del agua. Para eliminar o reducir la concentración de estos contaminantes se han implementado diversos procesos, tales como: intercambio iónico, precipitación-coagulación, electrodiálisis, nanofiltración, ósmosis inversa, y diálisis Donnan; sin embargo, la mayoría de estos métodos a menudo implican costos de operación elevados y mantenimiento continuo. El uso de adsorbentes diseñados específicamente para eliminar estos elementos representa una alternativa con gran potencial para ser aplicados a corto plazo en sistemas de tratamiento de agua. Una opción atractiva para mitigar la contaminación del agua por F- y As es el uso de carbón activado (CA) como material adsorbente. Sin embargo, este material tiene algunas limitaciones relacionadas con su capacidad y selectividad que deben ser superadas. La modificación de carbón activado con partículas de oxihidróxidos metálicos de tamaño nanométrico tiene el potencial de eliminar selectivamente estos contaminantes, sin embargo, el mayor reto es el anclaje de estos metales en la superficie del CA. Nuestro grupo de investigación ha contribuido en los últimos años a esta área de investigación mediante la síntesis de adsorbentes híbridos basados en oxihidróxidos metálicos-carbón con capacidad de adsorción elevada. Lo anterior considerando la relación entre el área específica, distribución de carga, grupos funcionales, contenido de metal y la capacidad de adsorción.""Water polluted with fluoride (F- ) and arsenic (As) is a problem of global relevance. The groundwater of several countries exceeds the allowable concentration limits for these compounds as recommended by the World Health Organization (WHO), thus posing a serious human health risk. For this reason, F- and As are considered priority pollutants that determine water quality. To eliminate or reduce the concentration of these contaminants, several processes have been implemented such as: ion exchange, precipitation- coagulation, electrodialysis, nano-filtration, reverse osmosis, and Donnan dialysis. However, most of these methods often involve high operating and maintenance costs. The use of adsorbents that are specifically designed for the removal of these elements represent a viable alternative for future water treatments system. An attractive option is the use of activated carbon (AC) as an adsorbent material. Nevertheless, limitations related to its capacity and selectivity must be overcome. The modification of the activated carbons surface with metal oxyhydroxides nanoparticles has the potential to selectively remove these contaminants. The biggest challenge is controlling the anchorage of the oxyhydroxide nanoparticles on the AC surface. Our research group has contributed in recent years to this research area by synthesizing hybrid adsorbents based on metal oxyhydroxides nanoparticles-AC with elevated adsorption capacities and chemical stability, this considering the relationship among surface area, charge distribution, functional groups, metal content, and contaminant uptake.
Microstructure and composition design of magnetic Ni-Mn-Sn Co-sputter deposited films
Get PDF"In this work, we study the effect of the substrate temperature (ST) during sputter-deposition as well as co-sputtering deposition on the fabrication of nanostructured Ni-Mn-Sn thin films. Sputtered films show Mn losses of around 10 at.% while the average grain size () increased from 30 nm to 105 nm with the increasing of ST. Mn losses compensation is proposed by co-sputtered deposition. With such a purpose a variable electrical power was applied to the radio frequency (RF) Mn cathode. By increasing the electrical power applied to the RF Mn cathode both Mn and Ni contents approach to the targeted nominal composition Ni:Mn:Sn = 50:37:13. Elemental chemical composition analyses show that the composition varied between Ni61.5Mn26.2Sn12.3 and Ni54.6Mn30.5Sn14.9 when the applied RF-power increased from 0 W to 30 W.
Newborn expression of microRNAs as potential early biomarkers for metabolic syndrome
Get PDF"El síndrome metabólico es un trastorno caracterizado por obesidad, hipertensión arterial, hipercolesterolemia, hiperlipidemia y alteraciones en el metabolismo de la glucosa, y constituye un factor de riesgo para el desarrollo de diabetes y enfermedades cardiovasculares. Las condiciones nutricionales, hormonales y metabólicas de la madre durante el embarazo y el posparto temprano pueden condicionar el desarrollo de enfermedades metabólicas en la vida adulta de los hijos. Este concepto, llamado “programación fetal”, sugiere la existencia de marcadores moleculares que permitirían estimar de forma temprana el riesgo de desarrollar síndrome metabólico e implementar medidas para prevenirlo. Este trabajo revisa el potencial de los microRNAs como biomarcadores para la detección temprana del síndrome metabólico dada su especificidad y estabilidad, su presencia en fluidos biológicos de obtención rutinaria en la clínica y su expresión temprana en diversas enfermedades.""Metabolic syndrome is a disorder characterised by obesity, hypertension, hypercholesterolemia, hyperlipidemia and alterations in glucose metabolism. It constitutes a risk factor for diabetes and cardiovascular disease development. Nutritional, hormonal and metabolic conditions of the mother during pregnancy and the early life of the offspring can determine metabolic disease development during the offspring's later life. This concept, called “fetal programming”, suggests the possibility of finding molecular markers to make early estimations for the risk of developing metabolic syndrome and of working on prevention strategies. This paper reviews the potential of microRNAs as early detection biomarkers for metabolic syndrome, given that they are specific and stable, are present in body fluids routinely obtained in clinics and have been found in early stages of several diseases.
La maquinaria de silenciamiento génico mediada por sRNAs de Arabidopsis thaliana y su papel en el establecimiento de una relación benéfica con Trichoderma atroviride
Get PDFTesis (Maestría en Ciencias en Biología Molecular)"Las plantas interactúan con microorganismos benéficos y deletéreos, que contrarrestan con sus sistemas de defensa. Para establecer una relación con las plantas, los microorganismos utilizan moléculas efectoras (principalmente proteínas) que suprimen su inmunidad. En las plantas, se han descrito la resistencia sistémica inducida (ISR), contra patógenos necrotróficos y la Resistencia sistémica adquirida (SAR), contra patógenos biotróficos. Se sabe que los RNAs pequeños de los hongos pueden silenciar la inmunidad de las plantas, al secuestrar su maquinaria del silenciamiento. En este trabajo, analizamos la expresión de los genes LOX-2, PR-1a, dicer (DCL) y argonauta (AGO) en Arabidopsis thaliana durante su interacción con Trichoderma atroviride, cuyos productos están involucrados en la ISR, la SAR y el silenciamiento génico mediado por RNAs pequeños respectivamente. Trichoderma indujo de manera sistémica, simultánea y transitoria la ISR y la SAR. La expresión de DCL1 a 4 y AGO1 a 10, presentó la misma cinética que PR-1a y LOX-2, pero con un patrón de expresión diferencial en hojas y raíces. El análisis transcripcional de PR-1a y LOX-2 en la mutante ago4-2, mostró niveles de inducción más bajos comparados con la silvestre, sin embargo, Trichoderma generó un efecto protector en Arabidopsis contra Pseudomonas syringae y Botrytis cinerea.""Plants interact with a plethora of beneficial and deleterious microorganisms to establish a pathogenic or beneficial relationship. To this end, plants have developed sophisticated defense and recognition mechanisms respectively. To establish a relationship with plants, pathogens and beneficial microorganisms use effector molecules (mainly proteins) to suppress plant immunity. Plants have developed the induced systemic resistance (ISR), against necrotrophic microorganisms, whereas the systemic acquired resistance (SAR) is effective against hemibiotrophic and biotrophic pathogens. Recently the small RNAs were described as silencers of plant immunity by hijacking the plant silencing machinery. In this paper, we analyzed the expression of PR-1a, LOX-2, dicer (DCL) and argonaute (AGO) genes in Arabidopsis thaliana during its interaction with T. atroviride, whose products are involved in ISR, SAR and small RNA-mediated gene silencing respectively. Trichoderma induced systemically, simultaneously and transiently the ISR and SAR. The fungus induced the expression of DCL1 to 4 and AGO1 to 10, in a similar kinetics to PR-1a and LOX-2, but with a different expression pattern in leaves and roots. Analysis of PR-1a and LOX-2 in the ago4-2 mutant inoculated with Trichoderma showed a lower expression compared to the wild-type, however, the fungus induced protection against P. syringae and B. cinerea in Arabidopsis.
Identificación y caracterización de la proteína Bl-ARC y su posible papel en el mecanismo de pupilación en Bifidobacterium longum subsp. infantis
Get PDF"La administración oral de bifidobacterias promueve el mantenimiento de la flora intestinal en humanos lo que estimula la respuesta inmune y tiene efectos preventivos en cáncer. A pesar de estas características altamente relevantes, poco se sabe de los eventos moleculares en este organismo y la relación con su hospedero. En nuestro laboratorio se estudian las funciones de las ATPasas de la familia AAA (ATPases Associated with diverse cellular Activities). ATPasas AAA están involucradas en procesos celulares y moleculares clave en todos los organismos. En un estudio previo (trabajo de tesis de Maestría), localizamos el gen IPR003593 AAA+ ATPase en el genoma de Bifidobacterium longum, cuya secuencia codifica una proteína de 56.1 kDa con un dominio característico AAA. Análisis filogenético permitió posicionarla dentro del grupo ARC AAA y denominarla Bl-ARC. Alineamientos del dominio N-terminal de Bl-ARC agrupó ATPasas que participan en la vía de degradación proteínica via proteosoma como ARC de Rhodococcus erythropolis, PAN de Methanococcus jannaschii, Mpa de Mycobacterium tuberculosis y la subunidad proteosomal Rpt1 de humano. En la organización genómica de B. longum, bl-arc está flanqueado por un grupo de genes que incluyen a pafA, pup y dop involucrados en el procesamiento de sustratos en el mecanismo de pupilación. No obstante, ha sido descrito que B. longum carece de los genes que codifican las subunidades α y β proteosomales (prcA y prcB). Estas características hacen aún más interesante el estudio del procesamiento de degradación y/o control de calidad de proteínas. Análisis estructurales preliminares de Bl-ARC confirmaron la formación de un complejo molecular homo-hexamérico de 336 kDa. La caracterización enzimática evidenció además actividad ATPásica en presencia de Mg+2 y ATP y sensibilidad en presencia de N-etilmaleimida (típico de proteínas AAA). Posteriormente se analizó la proteína Pup. Resultados del análisis de dicroísmo circular evidenciaron un patrón de desorden en su secuencia de aminoácidos; esta característica le confiere mayor flexibilidad para interactuar con otras proteínas para conducirlas a degradación. Análisis in silico de las proteínas Dop y PafA revelaron la conservación de sus estructuras y sitios clave contra proteínas ortólogas. Esto permitió la predicción de mecanismos basados en su estructura-función.""Oral administration of bifidobacteria improves intestinal flora in humans for stimulation of immune responses and possibly preventing cancer. Despite these relevant characteristics, information about molecular events is missing and the relationship along their host. In our laboratory we are studying the function of AAA proteins (ATPases Associated with diverse cellular Activities). AAA ATPases are involved in key cellular and molecular processes in all the organisms. In a previous study (M. Sc. Thesis), we found the gene IPR003593 AAA + ATPase core in Bifidobacterium longum genome. This gene codes a protein of 56.1 kDa with an AAA ATPase domain. Phylogenetic analysis positioned this sequence into the ARC AAA branch and we named it as Bl-ARC. N-terminal alignments of Bl-ARC grouped ATPases that participate in the degradation pathway via proteosome such as Rhodococcus erythropolis ARC, Archaeoglobus fulgidus PAN, Mycobacterium tuberculosis Mpa and the human proteasomal Rpt1 subunit. In the genome organization of B. longum, bl-arc is flanked by a cluster of genes that include pafA, pup and dop, all involved in substrate processing via pupylation. It has been described that B. longum lack the α y β proteosomal genes (prcA and prcB). This characteristic makes B. longum an attractive model to study the quality control of proteins and degradation processing. Preliminary structure analyses of Bl-ARC confirmed the formation of a homohexameric complex of 336 kDa. Enzymatic characterization showed Bl-ARC as an active ATPase Mg2+ and ATP dependent, and sensitive against N-ethylmaleimide (typical of AAA proteins). In addition, the Pup protein was analyzed by circular dicroism. Results showed an unruly pattern in its aminoacid sequence; this characteristic allows Pup to have flexibility to interact with other proteins and conduct them to degradation. In silico analysis of Dop and PafA revealed their structure are highly conserved against orthologues. This allowed the prediction of mechanisms based on their structure-function.
Mango (Mangifera indica L.) cv. Kent fruit mesocarp de novo transcriptome assembly identifies gene families important for ripening
Get PDF"Fruit ripening is a physiological and biochemical process genetically programmed to regulate fruit quality parameters like firmness, flavor, odor and color, as well as production of ethylene in climacteric fruit. In this study, a transcriptomic analysis of mango (Mangifera indica L.) mesocarp cv. "Kent" was done to identify key genes associated with fruit ripening. Using the Illumina sequencing platform, 67,682,269 clean reads were obtained and a transcriptome of 4.8 Gb. A total of 33,142 coding sequences were predicted and after functional annotation, 25,154 protein sequences were assigned with a product according to Swiss-Prot database and 32,560 according to non-redundant database. Differential expression analysis identified 2,306 genes with significant differences in expression between mature-green and ripe mango [1,178 up-regulated and 1,128 down-regulated (FDR <= 0.05)1. The expression of 10 genes evaluated by both gRT-PCR and RNA-seq data was highly correlated (R = 0.97), validating the differential expression data from RNA-seq alone. Gene Ontology enrichment analysis, showed significantly represented terms associated to fruit ripening like "cell wall," "carbohydrate catabolic process" and "starch and sucrose metabolic process" among others. Mango genes were assigned to 327 metabolic pathways according to Kyoto Encyclopedia of Genes and Genomes database, among them those involved in fruit ripening such as plant hormone signal transduction, starch and sucrose metabolism, galactose metabolism, terpenoid backbone, and carotenoid biosynthesis. This study provides a mango transcriptome that will be very helpful to identify genes for expression studies in early and late flowering mangos during fruit ripening.
Regulador conmutado usando convertidores de alta reducción para microprocesadores
Get PDF"La tendencia actual en el diseño de microprocesadores está caracterizada por fuentes de alimentación con un voltaje muy bajo (~ 1 V ), una ventana de regulación (~100 mV ), una gran relación de conversión (1/12 a 1/48), y adicionalmente un incremento en las corrientes de suministro (~ 100 A) con una alta rapidez (~ 300 A/µs). Estas tendencias representan un gran reto para el diseño de reguladores de voltaje que son los encargados de suministrar energía a los microprocesadores. Los reguladores de voltaje deben ser diseñados sin un número excesivo de capacitores en su salida. En principio un convertidor reductor óptimo es diseñado para que cumpla con los requerimientos de corriente en su salida. En estos convertidores es recomendable usar capacitores cerámicos con una resistencia serie equivalente pequeña, lo cual es sin duda la selección esperada en los reguladores de voltaje para la próxima generación de microprocesadores. Sin lugar a duda, el desarrollo de nuevas topologías jugará un papel importante para satisfacer los requisitos anteriores. En el Capítulo 2 se discuten algunas topologías que pueden proporcionar amplios rangos de conversión y un voltaje bajo. Se proporciona un estudio comparativo entre los convertidores reductores cuadrático convencional y cuadrático síncrono. En ambos casos, se presentan las consideraciones de diseño de los convertidores no solamente para que puedan proporcionar las relaciones de conversión requeridas sino también para los rizos en los voltajes y corrientes en los capacitores e inductores. En el Capítulo 3 se muestra como es posible obtener un amplio rango de conversión cuando se agrega un arreglo de capacitores y diodos al convertidor. Este esquema también se conoce como multiplicador de voltaje. Un esquema de control es propuesto en el Capítulo 4 el cual consiste en dos lazos de realimentación de acuerdo al control modo-corriente promedio. En el lazo interior se realimenta el error de la corriente con una alta ganancia y amplio ancho de banda para mejorar la velocidad de la respuesta transitoria. El lazo exterior de voltaje utiliza un control proporcional -integral con el propósito de regular el voltaje de salida. Esta estrategia de control funciona muy bien aún para amplios cambios en la carga. En el Capítulo 5 se concluye con algunos comentarios sobre las topologías presentadas y una perspectiva sobre trabajo futuro.""The present trend in the design of microprocessors is driven by power supplies with a very low output voltage (~ 1 V ), a regulation window (~ 100mV ), a wide voltage conversion (1/12 a 1/48), and additionally an increment of current supplied ( 100 A) with a fast response. This trend represents a great challenge in the design of voltage regulators who are responsible to supply energy to the microprocessors. Voltage regulators should be designed without the excessive use of capacitors in the output. As a first choice, an optimized buck converter should be designed such that the requirements of the output current can be satisfied. In this converter, ceramic capacitors with a small equivalent series resistance should be used, which is the expected choice in voltage regulators for the next generation of microprocessors. In fact, the development of new topologies will play an important role to satisfy the aforementioned requirements. In Chapter 2, a discussion is given for topologies that can satisfy a wide conversion ratio, a low voltage and a simple controller. A comparative study between the quadratic buck and synchronous converters is given. In both cases, the design considerations for the converters are given such that the required voltage conversions are obtained but the expressions for the voltage and current ripples of capacitors and inductors are given as well. In Chapter 3, it is shown how a wider range of conversion is obtained when an array of capacitors and diodes is added to the above converters. This scheme is also referred as a voltage multiplier. A controller is proposed in Chapter 4 based on average current-mode control that consists in two feedback loops. The inner current loop uses an error amplifier with high gain and wide bandwidth for a fast transient response. The outer voltage loop uses a proportional integral controller for voltage regulation purposes. The above control strategy works very well even for step changes in the load. In Chapter 5, a discussion is given about the topologies and a perspective of future work as well.
Oligonucleotides of Candida albicans, detection method and kit comprising same
No full text"The invention discloses an in vitro method for the identification of Candida albicans, the sequences associated to said identification, as well as diagnosis kits for identifying Candida albicans.""La invención describe un método in vitro de identificación de Candida albicans, las secuencias asociadas a dicha identificación, así como kits de diagnóstico para identificar Candida albicans.
Removing lateral chromatic aberration in bright field optical microscopy
Get PDF"We present an efficient alternative to remove lateral chromatic aberration (LCA) in bright field light microscopy images. Our procedure is based on error calibration using time-sequential acquisition at different wavelengths, and error correction through digital image warping. Measurement of the displacements of fiducial marks in the red and green images relative to blue provide calibration factors that are subsequently used in test images to realign color channels digitally. We demonstrate quantitative improvement in the position and boundaries of objects in target slides and in the color content and morphology of specimens in stained biological samples. Our results show a reduction of LCA content below the 0.1% level.
Arabidopsis thaliana polyamine content is modified by the interaction with different Trichoderma species
Get PDF"Plants are associated with a wide range of microorganisms throughout their life cycle, and some interactions result on plant benefits. Trichoderma species are plant beneficial fungi that enhance plant growth and development, contribute to plant nutrition and induce defense responses. Nevertheless, the molecules involved in these beneficial effects still need to be identify. Polyamines are ubiquitous molecules implicated in plant growth and development, and in the establishment of plant microbe interactions. In this study, we assessed the polyamine profile in Arabidopsis plants during the interaction with Trichoderma virens and Trichoderma atroviride, using a system that allows direct plant-fungal contact or avoids their physical interaction (split system). The plantlets that grew in the split system exhibited higher biomass than the ones in direct contact with Trichoderma species. After 3 days of interaction, a significant decrease in Arabidopsis polyamine levels was observed in both systems (direct contact and split). After 5 days of interaction polyamine levels were increased. The highest levels were observed with T. atroviride (split system), and with T. virens (direct contact). The expression levels of Arabidopsis ADC1 and ADC2 genes during the interaction with the fungi were also assessed. We observed a time dependent regulation of ADC1 and ADC2 genes, which correlates with polyamine levels. Our data show an evident change in polyamine profile during Arabidopsis – Trichoderma interaction, accompanied by evident alterations in plant root architecture. Polyamines could be involved in the changes undergone by plant during the interaction with this beneficial fungus.