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Search Results: 1 - 10 of 83485 matches for " Ricardo Antonio HERNáNDEZ VIRUEL "
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LAVADO DE SALES EN SUELOS ALUVIALES COSTEROS DE OAXACA, MéXICO, CON AGUAS RESIDUALES MUNICIPALES TRATADAS
Edgar Iván SáNCHEZ BERNAL,Héctor Manuel Ortega Escobar,Gelia Tomasa SANDOVAL OROZCO,Ricardo Antonio HERNáNDEZ VIRUEL
Revista internacional de contaminación ambiental , 2012,
Abstract: Los suelos de planicie aluvial costera de Colotepec, Oaxaca, con deficiente drenaje natural, napa freática somera e irrigados con aguas de pozo de moderada salinidad, acumulan sales en sus 20 cm superiores. Su tipogénesis forma Solonchaks que limitan el crecimiento y desarrollo de cultivos agrícolas. Con el fin de estudiar el desplazamiento de sales de la capa arable mediante su lixiviación con aguas residuales tratadas, como alternativa de uso sustentable para evitar su descarga sin tratar en la zona intermareal, así como la sobre extracción de aguas subterráneas por el riego, se experimentó en condiciones de invernadero el lavado de sales en columnas de suelo colectadas en campo. Se aplicó una norma de lavado (Qa/Qπ) = 1, equivalente a 54.82 m3/ha con los tratamientos agua destilada (control), agua de pozo, agua residual tratada y una mezcla de agua de pozo y agua residual tratada en proporción 1:1. La salinidad inicial edáfica se determinó en 5.40 g/L (91.83 Mg/ha). El porcentaje de sodio intercambiable fue superior a 15 % y el pH mayor a 8.5. La salinidad residual promedio del espesor de suelo (0-30 cm) lixiviado con agua de pozo fue de 0.67 g/L (11.39 Mg/ha) y el porcentaje de sodio intercambiable fue de 2.76 %, mientras que con agua residual tratada, se determinó en 0.86 g/L (14.62 Mg/ha) y el porcentaje de sodio intercambiable fue de 6.53 %. Estos valores indican adecuados niveles salinos y de sodio intercambiable. El lavado con ambos tipos de agua desalinizó en forma temporal el estrato arable.
Processing of Nuclear Viroids In Vivo: An Interplay between RNA Conformations
María-Eugenia Gas,Carmen Hernández,Ricardo Flores,José-Antonio Daròs
PLOS Pathogens , 2007, DOI: 10.1371/journal.ppat.0030182
Abstract: Replication of viroids, small non-protein-coding plant pathogenic RNAs, entails reiterative transcription of their incoming single-stranded circular genomes, to which the (+) polarity is arbitrarily assigned, cleavage of the oligomeric strands of one or both polarities to unit-length, and ligation to circular RNAs. While cleavage in chloroplastic viroids (family Avsunviroidae) is mediated by hammerhead ribozymes, where and how cleavage of oligomeric (+) RNAs of nuclear viroids (family Pospiviroidae) occurs in vivo remains controversial. Previous in vitro data indicated that a hairpin capped by a GAAA tetraloop is the RNA motif directing cleavage and a loop E motif ligation. Here we have re-examined this question in vivo, taking advantage of earlier findings showing that dimeric viroid (+) RNAs of the family Pospiviroidae transgenically expressed in Arabidopsis thaliana are processed correctly. Using this methodology, we have mapped the processing site of three members of this family at equivalent positions of the hairpin I/double-stranded structure that the upper strand and flanking nucleotides of the central conserved region (CCR) can form. More specifically, from the effects of 16 mutations on Citrus exocortis viroid expressed transgenically in A. thaliana, we conclude that the substrate for in vivo cleavage is the conserved double-stranded structure, with hairpin I potentially facilitating the adoption of this structure, whereas ligation is determined by loop E and flanking nucleotides of the two CCR strands. These results have deep implications on the underlying mechanism of both processing reactions, which are most likely catalyzed by enzymes different from those generally assumed: cleavage by a member of the RNase III family, and ligation by an RNA ligase distinct from the only one characterized so far in plants, thus predicting the existence of at least a second plant RNA ligase.
Tricobezoar gástrico y síndrome de Rapunzel en una adolescente
Ojeda López,Luis Alberto; Labaut Arévalo,Nadia; Gorina del Cristo,Ricardo; Hernández Dinza,Pablo Antonio;
MEDISAN , 2010,
Abstract: the case report of a 17 year-old adolescent , with poor social conditions, admitted at san juan de dios hospital, challapata municipality (bolivia), for presenting epigastralgia, nauseas and vomits is described . an upper digestive endoscopy was carried out and a case of upper intestinal occlusion due to gastric tricobezoar simulating a rapunzel syndrome was confirmed, reason why she had an emergent surgery. the postoperative clinical course was favorable and she was discharged after 7 days, with recommendations of attending the out patient department of general surgery and psychology.
Genotype frequencies of C/T-13910 and G/A-22018 polymorphisms in a Colombian Caribbean population do not correspond with lactase persistence prevalence reported in the region
Mendoza,Evelyn; Hernández,Adriana Carolina; Wilches,Ricardo; Varela,Lourdes Luz; Villarreal,José Luis; Barrera,Luis Alejandro; Villanueva,Daniel Antonio;
Colombia Médica , 2010,
Abstract: introduction: the c/t-13910 and g/a-22018 polymorphisms located upstream of the lactase gene are reliable predictors of lactase persistence in caucasian-derived populations. assessing the presence and distribution of these polymorphisms in other populations is central to developing genotyping assays and understanding the evolutionary mechanism behind this trait in several human populations. objective: genotyping the c/t-13910 and g/a-22018 polymorphisms in a sample of colombian caribbean individuals. materials and methods: the polymorphisms were identified through polymerase chain reaction/restriction fragment length polymorphism. amplified fragments were digested using hinf i and hha i. arlequin v. 3. 1 was used to determine allelic and genotypic frequencies, hardy weinberg equilibrium, and linkage disequilibrium. results: genotypic frequencies were cc (81.4%), ct (18.6%), and tt (0%) for the c/t-13910 polymorphism. frequencies were aa (55.5%), ga (45.5%), and gg (0%) for the g/a-22018 polymorphism. no linkage disequilibrium was found between the two loci. only the locus containing the c/t-13910 polymorphism was found in hardy weinberg equilibrium. conclusion: the allelic and genotypic distributions observed in this first genotyping study in a colombian caribbean population indicate a distribution pattern different from the one of the north european caucasians and do not correspond to the lactase persistence prevalence reported for caribbean populations.
Tricobezoar gástrico y síndrome de Rapunzel en una adolescente GastricTrichobezoar and Rapunzel syndrome in an adolescent
Luis Alberto Ojeda López,Nadia Labaut Arévalo,Ricardo Gorina del Cristo,Pablo Antonio Hernández Dinza
MEDISAN , 2010,
Abstract: Se describe el caso clínico de una adolescente de 17 a os de edad, con malas condiciones sociales, ingresada en el Hospital San Juan de Dios, municipio de Challapata (Bolivia), por presentar epigastralgia, náuseas y vómitos. Se realizó endoscopia digestiva superior y se confirmó un cuadro de oclusión intestinal alta por tricobezoar gástrico en forma de síndrome de Rapunzel, por lo cual fue operada de urgencia. La evolución posoperatoria resultó favorable y egresó a los 7 días, con recomendaciones de asistir a consultas externas de cirugía general y psicología. The case report of a 17 year-old adolescent , with poor social conditions, admitted at San Juan de Dios Hospital, Challapata municipality (Bolivia), for presenting epigastralgia, nauseas and vomits is described . An upper digestive endoscopy was carried out and a case of upper intestinal occlusion due to gastric tricobezoar simulating a Rapunzel syndrome was confirmed, reason why she had an emergent surgery. The postoperative clinical course was favorable and she was discharged after 7 days, with recommendations of attending the out patient department of general surgery and psychology.
Obtención de crudos de saponinas hipocolesteromizantes del Chenopodium quinoa Willd
Hernández Royero,Ricardo;
Revista Cubana de Medicina Militar , 1997,
Abstract: crudes of saponins were obtained from the small thin shell of grains of chenopodium quinoa willd (quinúa) by reflow with ethanol at 80 % v/v in order to use them as anticholesteraemia agents. the different batches of gross saponins obtained showed an average yield of 37.12 % on the basis of the total amount of small thin shell (8.03 %) and of 2.98 % on the basis of the whole number of grains. these products reacted strongly in the tests of liebermann-burchard and selivoflo, and their hemolytic potency (h50 in mg/ml) was in the run from 42.6 to 28.4. 6 samples of crudes were subjected to saponification and no significant changes were observed in the hemolytic potency of the saponified products (h50 between 37.2 and 22.7). this fact, and the fact that the total of crudes had a negative reaction in the fehling and molish's tests, suggest that the products obtained are in the form of sapogenins or other non-saponifiable derivatives.
Obtención de crudos de saponinas hipocolesteromizantes del Chenopodium quinoa Willd Obtention of crudes of saponins from chenopodium quinoa willd as anticholesteraemia agents
Ricardo Hernández Royero
Revista Cubana de Medicina Militar , 1997,
Abstract: Para su empleo como agente hipocolesteromizante, se procedió a la obtención de crudos de saponinas a partir de la cascarilla de granos de Chenopodium quinoa Willd (quinúa), mediante reflujo con etanol al 80 % v/v. Los diferentes lotes de saponinas brutas obtenidos presentaron un rendimiento promedio de 37,12 %, sobre la base del total de cascarilla (8,03 % de la masa de granos) y de 2,98 % sobre la base del total de granos. Estos productos reaccionaron fuertemente en las pruebas de Liebermann-Burchard y Selivoflo, y su potencia hemolítica (H50 en mg/mL) se enmarcó en un recorrido de 42,6 hasta 28,4. Seis muestras de crudos fueron sometidas a saponificación sin que se observaron cambios notables en la potencia hemolítica de los productos saponificados (H50 entre 37,2 y 22,7). Este hecho, unido a que el total de los crudos obtenidos manifestaron una reacción negativa en las pruebas de Fehling y Molish. Sugieren que los productos obtenidos se encuentran en forma de sapogeninas u otros derivados "no saponificables". Crudes of saponins were obtained from the small thin shell of grains of Chenopodium Quinoa Willd (quinúa) by reflow with ethanol at 80 % v/v in order to use them as anticholesteraemia agents. The different batches of gross saponins obtained showed an average yield of 37.12 % on the basis of the total amount of small thin shell (8.03 %) and of 2.98 % on the basis of the whole number of grains. These products reacted strongly in the tests of Liebermann-Burchard and Selivoflo, and their hemolytic potency (H50 in mg/mL) was in the run from 42.6 to 28.4. 6 samples of crudes were subjected to saponification and no significant changes were observed in the hemolytic potency of the saponified products (H50 between 37.2 and 22.7). This fact, and the fact that the total of crudes had a negative reaction in the Fehling and Molish's tests, suggest that the products obtained are in the form of sapogenins or other non-saponifiable derivatives.
Caracterización morfológica de la calabaza pipiana (Cucurbita argyrosperma Huber)
Rodríguez-Amaya, Ricardo;Montes-Hernández, Salvador;Rangel-Lucio, José Antonio;Mendoza-Elos, Mariano;Latournerie-Moreno, Luis;
Agricultura técnica en México , 2009,
Abstract: the pipiana squash (cucurbita argyrosperma huber) lacks formal descriptors of their existent morphological diversity in mexico. with this antecedent and regarding the importance of conserving and to describe the genetic resources of this species, a research was carried out with the aim of characterizing 32 accessions of pipiana squash from the gene bank of the instituto nacional de investigaciones forestales agrícolas y pecuarias, at campo experimental bajio, mexico during the spring-summer cycle (2006). seedlings of the 32 populations were distributed in the field under a complete random block design, and the agronomic handling was carried out according to the techniques used for commercial squash production in the "bajio guanajuatense" of mexico. for the characterization, two sets of descriptors were used, one set included 37 qualitative traits and a second set of 13 quantitative traits; traits were recorded during the cultivation cycle and at post harvest. data handling included principal components and clusters analysis. in the qualitative traits the distribution of the tertiary color, intensity of spots, color of the margin and seed coat plus the form of the leaf border, showed large variation in the evaluated accessions, these traits influenced the formation of seven groups of accessions. meanwhile, the quantitative traits weight of one hundred seeds with and without coat, fruit weight and days to flowering contributed more to the distinction of the characterized accessions, separating them in five groups. the characteristics of anthropocentric interest, weigh of a hundred seeds with and without coat, showed the most diversity in the germplasm of pipiana squash.
Mal de Pott en pediatría: presentación de 5 casos y revisión de la literatura
Abreu Suárez,Gladys; González Valdés,José Antonio; Zamora Fuentes,Ricardo; Portuondo Leyva,Reyna; Sandín Hernández,Natacha; Pérez,Aurelia;
Revista Cubana de Pediatr?-a , 2002,
Abstract: 5 of the 6 children affected by pott?s disease from 1995 to 2001 are presented in this paper for an incidence of 4.5 % of the total of cases of infantile tuberculosis in cuba. most of the children were about 2 years old. a predominance of lumbar affection was observed in 4 patients. the clinical picture was insidious and back pain and walking disorders were more frequent. the diagnosis was clinicoradiological and tuberculin was positive in 4 children. micobacterium tuberculosis was only isolated from a patient with concomitant pulmonary injuries. paravertebral abscesses (2 in the dorsal region and the other in the psoas) were found in 3 patients. there are still 3 patients under treatment: one of the two that were cured suffers from loss of the physiological lumbar lordosis and the other lost a vertebral body and presents a mild residual hump. it is concluded that though infantile tuberculosis is not a health problem in cuba and pott?s disease is not common, it should be taken into account when a child with insidious manifestations of walking disorders and back pain seeks medical assistance.
Post-traumatic hepatic artery pseudoaneurysm treated with endovascular embolization and thrombin injection
Lloret Esta? Francisco, López Conesa Asunción, Capel Alemán Antonio, Robles Campos Ricardo, Reus Pintado Manuel, Marín Hernández Caridad
World Journal of Hepatology , 2010,
Abstract: Post-traumatic hepatic artery pseudoaneurysm is uncommon, appearing in approximately 1% of hepatic trauma cases. Most are extrahepatic (80%) and have a late onset. Although they are usually asymptomatic, they should always be treated becasue of the high risk of complications, especially breakage. Currently the treatment of choice is endovascular embolization with coils or the exclusion of the pseudoaneurysm using other intravascular devices. Recently there have been accounts of a treatment that combines embolization with coils and image-guided percutaneous human thrombin injection. We present a case of post-traumatic hepatic artery pseudoaneurysm that was successfully treated using this combined technique
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