274 research outputs found
Determinación preliminar de género y densidades poblacionales de nemátodos asociados a cultivo de arroz (Oryza sativa) en la Región Huertar Norte de Costa Rica
Proyecto de graduación (Bachillerato en Ingeniería en Agronomía) Instituto Tecnológico de Costa Rica, Escuela de Ingeniería en Agronomía, 2006Este trabajo de investigación se efectuó en el cultivo de arroz
(Oryza sativa) en la Región Huetar Norte de Costa Rica. El estudio compendió
los meses de agosto y octubre del 2006 con el objetivo de caracterizar las
poblaciones de nemátodos fitoparásitos presentes en la región y asociados a
este cultivo. Se evaluaron 7 fincas asociadas a la Corporación Arrocera
Nacional (CONAROZ) con un área cultivada de 663 Ha aproximadamente. En
éstas fincas se colectaron 24 muestras de raíz y 24 muestras de suelo. Los
principales géneros asociados al cultivo de Arroz en la Región Huetar Norte de
Costa Rica son: Pratylenchus, Meloidogyne, Helicotylenchus,
Tylenchorhynchus, Tylenchus y Criconomella, en orden de importancia
respectivamente. Pratylenchus spp puede ser considerado el nemátodo de
mayor importancia en la Región Huetar Norte de Costa Rica para el cultivo de
arroz. Pratylenchus spp fue el nemátodo que presentó las mayores densidades
poblacionales en raíz (40. 748 nematodos/100g. raíz), con una frecuencia del
100%. Asimismo Pratylenchus spp obtuvo la segunda población
(55 nemátodos/100g. suelo) y frecuencia más alta (91,67%) en suelo. Por otra
parte Meloidogyne spp presentó una densidad poblacional de
31. 080 nemátodos/100g. raíz y una frecuencia en raíz del 95,83%. Además,
el género Helicotylenchus se encontró en la más alta densidad
(77 nematodos/100g. suelo) y frecuencia (95,83%) en suelo, por lo que se
podría considerar como un problema dentro del cultivo. Tylenchorhynchus spp
y Tylenchus spp registran frecuencias similares (79,17% y 75%
respectivamente); de la misma forma obtuvieron densidades poblacionales en
100 g. de suelo de (5 y 3 respectivamente). Posteriormente Criconomella spp
presentó la mas baja densidad poblacional (0,5 nemátodos/100g. suelo) y
frecuencia (29,17%) en suelo. Estos tres géneros no se consideraron como
problemas dentro del cultivo de arroz.Corporación Arrocera Nacional (CONAROZ)
Instituto Tecnológico de Costa Rica Sede San Carlos. Escuela de Ingeniería en Agronomía
Safety and Efficacy of a New Synthetic Material Based on Monetite, Silica Gel, PS-Wallastonite, and a Hydroxyapatite Calcium Deficient: A Randomized Comparative Clinic Trial
Background and Objectives: Maxillary bone defects related to post-extraction alveolar ridge resorption are usual. These defects may lead to failure in further surgical implant phases given the lack of bone volume to perform the dental implant. The objective of this clinical assay was to evaluate the safety and efficacy of an experimental synthetic bone substitute in the preservation of post-extraction maxillary alveoli. Materials and Methods: 33 voluntary patients who had at least one maxillary premolar tooth that was a candidate for exodontia (n = 39) and subsequent implant rehabilitation participated. The regenerated alveoli were monitored by means of periodic clinical examinations (days 9 ± 1, 21 ± 4, 42 ± 6, and 84 ± 6), measuring the height and width of the alveolar crest (days 0 and 180 ± 5), measurement of radiodensity using tomographic techniques (days 0–5 and 175 ± 5), and histological examination of biopsies collected at 180 ± 5 days. Results: No significant differences were observed during the entire follow-up period between the two groups with respect to the safety variables studied. A variation in width of −0.9 ± 1.3 mm and −0.6 ± 1.5 mm, and a variation in height of −0.1 ± 0.9 mm and −0.3 ± 0.7 mm was observed for experimental material Sil-Oss® and Bio-Oss®, respectively. The radiodensity of the alveoli regenerated with the experimental material was significantly lower than that corresponding to Bio-Oss®. However, the histological study showed greater osteoid matrix and replacement of the material with newformed bone in the implanted beds with the experimental material. Conclusions: Both materials can be used safely and proved equally effective in maintaining alveolar flange dimensions, they are also histologically biocompatible, bioactive and osteoconductive. The experimental material showed the advantage of being resorbable and replaced with newformed bone, in addition to promoting bone regeneration
Maximizing furfural concentration from wheat straw and Eucalyptus globulus by nonisothermal autohydrolysis
The autohydrolysis process as a method for selective extraction of hemicelluloses and conversion to furfural was proposed for lignocellulosic raw materials. Samples of wheat straw (WS) and Eucalyptus globulus (EG) were subjected to nonisothermal autohydrolysis, defined by temperature 180–240°C. Within a biorefinery scheme for the selected materials, the aim of this study is both (a) to optimize furfural processing technology to enable higher yields and improved productivity from EG and WS by autohydrolysis and (b) to not excessively degrade the remaining polymeric constituents (glucan) in solid to facilitate a potential later use. Differences in the rate of the dehydration reaction of xylose to furfural have been observed, and it is faster in the case of WS with respect to that observed for eucalyptus. In that form, 4.25 g/100 g raw material (26% of the initial xylan in WS) could be found at 220°C, and an increase in the temperature (240°C) yielded 4.54 g/100 g raw material, 28% of the initial xylan. In EG, the increase in the hydrolysis temperature (240°C) yielded liquor with higher contents of furfural (4.45 g/100 g raw material, 25% of the initial xylan) and acetic acid (4.49 g/100 g raw material) and smaller contents of arabinose and xylan. In WS, a faster dehydration is found
Nuevos vidrios para reducir la demanda térmica de edificios
España es un país con gran dependencia energética del exterior, donde en el año 2011 más del 76% de la energía se debió importar. Por sectores, la edificación es uno de los consumidores más importantes; en el año 2010 en las viviendas y en los comercios se llegaron a demandar el 14% y el 8% del consumo energético nacional respectivamente. Las necesidades energéticas de los edificios son tanto eléctricas (electrodomésticos, ordenadores, iluminación…), como térmicas (climatización y ACS). Uno de los aspectos que tiene gran influencia sobre esta demanda es la epidermis del edificio, teniendo
gran relevancia en ello las superficies acristaladas. Estas tienen aspectos positivos (favorecen la iluminación natural y aumentan la habitabilidad de los locales) y negativos (aumentan la demanda energética de la climatización).
Intentando reducir la demanda térmica, el mercado tradicional se dedicó a mejorar los vidrios: aumentando el espesor, introduciendo una o varias cámaras de aire intermedias, y mejorando la calidad para disminuir el calor radiante que los atraviesa. Pero en los últimos años se han ido aplicando diferentes tecnologías que han permitido fabricar los llamados vidrios activos o inteligentes. Éstos, mediante diferentes fenómenos físicos, modifican su comportamiento respecto al paso de la radiación solar, y por lo tanto mejoran su comportamiento térmico con lo que reducen la demanda térmica del edificio.
En esta ponencia se realiza un estudio, mediante simulación, del comportamiento de la demanda térmica en un edificio tomando como variable el factor solar de los vidrios que componen los huecos en las
diferentes fachadas. Además, se presentan los diversos tipos de vidrios activos o inteligentes que se están introduciendo en el mercado; la incipiente irrupción de estos vidrios en el mercado obligará a la modificación de los programas de cálculo de cargas térmicas y simulación de demanda energética para que consideren su inclusión entre los elementos del edificio, ya que estos programas tienen en cuenta aspectos como la colocación de toldos u otras protecciones, pero no el cambio en las propiedades del vidrio
Caracterización y degradación de los materiales graníticos de la Colegiata de San Isidro, Madrid, España
Original granitoids from the façade of the Colegiata de San Isidro are medium-grained-biotitic adamellites, from quarries of the Valdemorillo area (Madrid). The petrophysical properties of the materials allow to establish a clear difference between the two original granites: the most abundant one (A), with a lower porosity, lower water sorption capacity, a lower water vapour permeability coefficient, a higher ultrasonic waves transmission velocity, and a higher strength, respect to the least abundant granite (B). So it can be said the former is more resistant and of better quality than B-granite, or in other words, is a less-alterable granite than B-granite. In relation to the granites alteration trend, data make possible to establish that A-granite suffers less alteration than B-granite, because in the latter, values of the properties determined in internal and external sections, vary much more than for the A-granite. A brief reference to the conservation state of the main façade and to the monitoring of the atmospheric pollutants registered by two stations close to the building, with the aim of determining its inluence on the material degradation, which mainly consists of soiling and blackenning
CHL1 hypermethylation as a potential biomarker of poor prognosis in breast cancer
The CHL1 gene encodes a cell-adhesion molecule proposed as being a putative tumour-suppressor gene in breast cancer (BC). However, neither the underlying molecular mechanisms nor the clinical value of CHL1 downregulation in BC has been explored. The methylation status of three CpG sites in the CHL1 promoter was analysed by pyrosequencing in neoplastic biopsies from 142 patients with invasive BC and compared with that of non-neoplastic tissues. We found higher CHL1 methylation levels in breast tumours than in non-neoplastic tissues, either from mammoplasties or adjacent-to-tumour, which correlated with lower levels of protein expression in tumours measured by immunohistochemistry. A panel of five BC cell lines was treated with two epigenetic drugs, and restoration of CHL1 expression was observed, indicating in vitro dynamic epigenetic regulation. CHL1 was silenced by shRNA in immortalized but non-neoplastic mammary cells, and enhanced cell proliferation and migration, but not invasion, were found by real-time cell analysis. The prognostic value of CHL1 hypermethylation was assessed by the log-rank test and fitted in a Cox regression model. Importantly, CHL1 hypermethylation was very significantly associated with shorter progression-free survival in our BC patient series, independent of age and stage (p = 0.001). In conclusion, our results indicate that CHL1 is downregulated by hypermethylation and that this epigenetic alteration is an independent prognostic factor in BC
Control jerárquico en micro-redes AC
Los sistemas eléctricos experimentan cambios importantes relacionados con su composición y la estructura, así como en las estrategias de control, protección y operación. Las micro-redes están encargadas de suministrar la energía al usuario final, y son objeto de valiosos estudios y publicaciones actuales, debido principalmente a que contribuyen con la integración de sistemas de generación distribuida y de unidades almacenamiento de energía a pequeña escala. Las micro-redes son sistemas de energía que funcionan de manera controlada, ya que en la mayoría de los casos hay disponibilidad de mediciones, algoritmos de control y actuadores. Las mediciones de voltaje y corriente se utilizan para analizar el comportamiento local en varios lugares de la micro-red. Los algoritmos de control se aplican para tomar decisiones que permitan alcanzar los objetivos de control, como la regulación de la tensión y la frecuencia, y el seguimiento de potencia, entre otros. Los actuadores más importantes en las micro-redes son los convertidores de potencia, que interconectan tanto las fuentes primarias como los dispositivos de almacenamiento de energía con las otras partes de la micro-red. Estos actuadores son responsables de entregar la energía producida por las fuentes primarias a la micro-red, y también de administrar el estado de carga de los dispositivos de almacenamiento de energía. Este libro contiene los aspectos fundamentales del desarrollo de esquemas de control de convertidores del tipo fuente de tensión (voltage source converter - VSC), aplicados a las micro-redes, bajo el enfoque de optimización unificado. Las estrategias de control desarrolladas consideran los diferentes niveles de control jerárquico que
incluye: el control de nivel cero en sus lazos interno y externo; el control primario orientado a mantener la estabilidad del sistema luego de una perturbación; el control secundario orientado a mejorar la calidad de la tensión y la frecuencia luego de la acción del control primario; y finalmente, el control terciario, asociado a la operación de la micro-red, considerando la disponibilidad del recurso energético primario, los requerimientos de los clientes y los aspectos económicos de la operación
Silver clusters of five atoms as highly selective antitumoral agents through irreversible oxidation of thiols
Low atomicity clusters present properties dependent on the size, due to the quantum confinement, with well-defined electronic structures and high stability. Here it is shown that Ag5 clusters catalyze the complete oxidation of sulfur to S+6. Ag5 catalytic activity increases with different oxidant species in the order O2 ≪ H2O2 < OH•. Selective oxidation of thiols on the cysteine residues of glutathione and thioredoxin is the primary mechanism human cells have to maintain redox homeostasis. Contingent upon oxidant concentration, Ag5 catalyzes the irreversible oxidation of glutathione and thioredoxin, triggering apoptosis. Modification of the intracellular environment to a more oxidized state to mimic conditions within cancer cells through the expression of an activated oncogene (HRASG12V) or through ARID1A mutation, sensitizes cells to Ag5 mediated apoptosis. While cancers evolve to evade treatments designed to target pathways or genetic mutations that drive them, they cannot evade a treatment that takes advantage of aberrant redox homeostasis, which is essential for tumor progression and metastasis. Ag5 has antitumor activity in mice with orthotopic lung tumors reducing primary tumor size, and the burden of affected lymphatic nodes. The findings suggest the unique intracellular redox chemistry of Ag5 may lead to new redox-based approaches to cancer therapyThis research was partially supported by 1) “la Caixa” Foundation, Ref. LCF/PR/PR12/11070003 to F.D. and M.A.L.Q.; 2) Ministerio de Ciencia, Innovación y Universidades (MAT2017-89678-R, AEI/FEDER, UE) to F.D. and A.V.; 3) the Consellería de Educación (Xunta de Galicia), Grants No. Grupos Ref. Comp. ED431C 2017/22, ED431C 2019/13 and AEMAT-ED431E2018/08 to M.A.L.Q.; and ED431C 2019/13 to A.V. This project has received funding from the European Union's Horizon 2020 Research and Innovation Programme (Bac-To-Fuel) under Grant Agreement No. 825999 (M.A.L.Q.). J.C.H. acknowledge financial support from European Union's Horizon 2020 research and innovation programme under grant agreement no. 823717-ESTEEM3, and the MICIIN (projects PID2019-107578GA-100 and PID-110018GA-100). J.M.D, L.J.G., and F.G.R. thank to the ANPCyT (PICT 2015-2285 and 2017-3944), UNLP (Project 11/X790) and the partial support by the Laboratório Nacional de Luz Síncrotron (LNLS, Brazil) under proposal SXS-20180280. G.B. acknowledges the CINECA Award N. IsC51, year 2017, under the ISCRA initiative, for the availability of high-performance computing resources and support. D.B. expresses gratitude for a postdoctoral grant from Xunta de Galicia, Spain (POS-A/2013/018). B.D. expresses gratitude for a predoctoral grant from MICINN, Spain (BES-2016-076765). F.D. and A.V. also acknowledged Xunta de Galicia (Centro singular de investigación de Galicia accreditation 2019-2022 ref ED431G 2019/02) and the European Union (European Regional Development Fund – ERDF). Work in M.P.M.'s lab was supported by the Medical Research Council UK (MC_U105663142). T.G.C. gratefully acknowledges the technical assistance of María José Otero-Fraga (FIDIS)S
Ajustando RFR por Preditores de Discordância, “The Adjusted RFR”: Uma Metodologia Alternativa para Melhorar a Capacidade Diagnóstica de Índices Coronarianos
Background: Cutoff thresholds for the "resting full-cycle ratio" (RFR) oscillate in different series, suggesting that population characteristics may influence them. Likewise, predictors of discordance between the RFR and fractional flow reserve (FFR) have been documented. The RECOPA Study showed that diagnostic capacity is reduced in the RFR "grey zone", requiring the performance of FFR to rule out or confirm ischemia.
Objectives: To determine predictors of discordance, integrate the information they provide in a clinical-physiological index, the "Adjusted RFR", and compare its agreement with the FFR.
Methods: Using data from the RECOPA Study, predictors of discordance with respect to FFR were determined in the RFR "grey zone" (0.86 to 0.92) to construct an index ("Adjusted RFR") that would weigh RFR together with predictors of discordance and evaluate its agreement with FFR.
Results: A total of 156 lesions were evaluated in 141 patients. Predictors of discordance were: chronic kidney disease, previous ischemic heart disease, lesions not involving the anterior descending artery, and acute coronary syndrome. Though limited, the "Adjusted RFR" improved the diagnostic capacity compared to the RFR in the "grey zone" (AUC-RFR = 0.651 versus AUC-"Adjusted RFR" = 0.749), also showing an improvement in all diagnostic indices when optimal cutoff thresholds were established (sensitivity: 59% to 68%; specificity: 62% to 75%; diagnostic accuracy: 60% to 71%; positive likelihood ratio: 1.51 to 2.34; negative likelihood ratio: 0.64 to 0.37).
Conclusions: Adjusting the RFR by integrating the information provided by predictors of discordance to obtain the "Adjusted RFR" improved the diagnostic capacity in our population. Further studies are required to evaluate whether clinical-physiological indices improve the diagnostic capacity of RFR or other coronary indices.Fundamento: Os limiares de corte para a “relação do ciclo completo de repouso” (RFR) oscilam em diferentes séries, sugerindo que as características da população podem influenciá-los. Da mesma forma, foram documentados preditores de discordância entre a RFR e a reserva de fluxo fracionado (FFR). O Estudo RECOPA, mostrou que a capacidade diagnóstica está reduzida na “zona cinzenta” da RFR, tornando necessária a realização de FFR para descartar ou confirmar isquemia.
Objetivos: Determinar os preditores de discordância, integrar as informações que eles fornecem em um índice clínico-fisiológico: a “RFR Ajustada”, e comparar sua concordância com o FFR.
Métodos: Usando dados do Estudo RECOPA, os preditores de discordância em relação à FFR foram determinados na “zona cinzenta” da RFR (0,86 a 0,92) para construir um índice (“RFR Ajustada”) que pesaria a RFR juntamente com os preditores de discordância e avaliar sua concordância com a FFR.
Resultados: Foram avaliadas 156 lesões em 141 pacientes. Os preditores de discordância foram: doença renal crônica, cardiopatia isquêmica prévia, lesões não envolvendo a artéria descendente anterior esquerda e síndrome coronariana aguda. Embora limitada, a “RFR Ajustada” melhorou a capacidade diagnóstica em comparação com a RFR na “zona cinzenta” (AUC-RFR = 0,651 versus AUC-“RFR Ajustada” = 0,749), mostrando também uma melhora em todos os índices diagnósticos quando foram estabelecidos limiares de corte otimizados (sensibilidade: 59% a 68%; especificidade: 62% a 75%; acurácia diagnóstica: 60% a 71%; razão de verossimilhança positiva: 1,51 a 2,34; razão de verossimilhança negativa: 0,64 a 0,37).
Conclusões: Ajustar a RFR integrando as informações fornecidas pelos preditores de discordância para obter a “RFR Ajustada” melhorou a capacidade diagnóstica em nossa população. Mais estudos são necessários para avaliar se os índices clínico-fisiológicos melhoram a capacidade diagnóstica da RFR ou de outros índices coronarianos
A genome-wide association study suggests the HLA Class II region as the major susceptibility locus for IgA vasculitis.
The genetic component of Immunoglobulin-A (IgA) vasculitis is still far to be elucidated. To increase the current knowledge on the genetic component of this vasculitis we performed the first genome-wide association study (GWAS) on this condition. 308 IgA vasculitis patients and 1,018 healthy controls from Spain were genotyped by Illumina HumanCore BeadChips. Imputation of GWAS data was performed using the 1000 Genomes Project Phase III dataset as reference panel. After quality control filters and GWAS imputation, 285 patients and 1,006 controls remained in the datasets and were included in further analysis. Additionally, the human leukocyte antigen (HLA) region was comprehensively studied by imputing classical alleles and polymorphic amino acid positions. A linkage disequilibrium block of polymorphisms located in the HLA class II region surpassed the genome-wide level of significance (OR = 0.56, 95% CI = 0.46-0.68). Although no polymorphic amino acid positions were associated at the genome-wide level of significance, P-values of potential relevance were observed for the positions 13 and 11 of HLA-DRB1 (P = 6.67E-05, P = 1.88E-05, respectively). Outside the HLA, potential associations were detected, but none of them were close to the statistical significance. In conclusion, our study suggests that IgA vasculitis is an archetypal HLA class II disease
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