1,446 research outputs found
On Observability of Chaotic Systems: An Example
The concept of observability of a special chaotic system, namely the dyadic map, is studied here in case the observation is not exact. The usual concept of observable subspace does not distinguish among the behavior of different models. It turns out that a suitable extension of this concept can be obtained using the idea of Hausdorff dimension. It is shown that this dimension increases as the observation error becomes smaller, and is equal to one only if the system is observable
Ibuprofen modulates allosterically NO dissociation from ferrous nitrosylated human serum heme-albumin by binding to three sites
Human serum albumin (HSA) is a monomeric allosteric protein. Here, the effect of ibuprofen on denitrosylation kinetics (k(off)) and spectroscopic properties of HSA-heme-Fe(II)-NO is reported. The k(off) value increases from (1.4 +/- 0.2) x 10(-4) s(-1), in the absence of the drug, to (9.5 +/- 1.2) x 10(-3) s(-1), in the presence of 1.0 x 10(-2) M ibuprofen, at pH 7.0 and 10.0 degrees C. From the dependence of k(off) on the drug concentration, values of the dissociation equilibrium constant for ibuprofen binding to to HSA-heme-Fe(II)-NO (K-1 = (3.1 +/- 0.4) x 10(-7) M, K-2= (1.7 +/- 0.2) x 10(-4) M. and K-3 (2.2 +/- .2) x 10(-3) M) were determined. The K-3 value corresponds to the HSA-heme-Fe(II)-NO determined by monitoring drug-dependent absorbance spectroscopic changes (H = (2.6 +/- 0.3) x 10(-3) M). Present data indicate that ibuprofen binds to the FA3-FA4 cleft (Sudlow's site II), to the FA6 site, and possibly to the FA2 pocket, inducing the hexa-coordination of HSA-heme-Fe(II)-NO and triggering the heme-ligand dissociation kinetics. (C) 2009 Elsevier Inc. All rights reserved
Stone fruits, pears and citrus integrated pest management interdisciplinary network with focus on the exchange of knowledge, innovation and technology transfer (RED-MIFRUT).
The creation of a stone fruit, pear and citrus integrated pest management (IPM) interdisciplinary network (entomology, and field and post-harvest pathology) to strengthen the exchange of knowledge and experiences of participating working groups is proposed; emphasizing on the development of new methodologies to improve the IPM that reduce the use of pesticides and presence of residues, and improves the ability to transfer technology to society. The specific objectives are: 1) Promote the collaboration among the multidisciplinary groups including knowledge transfer themes, integrating the social area. 2) Elaborate guidelines for the exchange of biological and experimental material for research. 3) Facilitate the implementation of research projects coordinated by the participating groups. 4) Analyze aspects related to effective technology transfer to the society, in each of the regions, and propose specific actions. 5) Build a database of the main pests and pathogens (including their vectors) of the fruits involved, and the strategies used for their control. 6) Create the conditions to convert the network in a source of information about IPM in fruits for the social agents. 7) Promote the public-private interaction to improve the adoption of the available technologies, and guide the development of new knowledge. 8) Establish contact with other existing networks with similar themes, like the European network Endure (European Network for the Durable Exploitation of Crop Protection Strategies), and with other institutions, like IOBC. In May of 2014, the first meeting of the area coordinators for each country was held in RĂo Negro, Argentina. A document was elaborated with the situation and the alternatives for pest control and cultivation in the respective participating countries. The results will be available in the World Wide Web and will be broadcast in the main participating centers
Chitosan-whey protein edible films produced in the absence or presence of transglutaminase: Analysis of their mechanical and barrier properties
Chitosan-whey protein edible films with different protein concentrations were prepared in the absence or presence of microbial transglutaminase as cross-linking agent. The films prepared in the presence of the enzyme showed low solubility at a wide range of pH, a lower degree of swelling, and good biodegradability following protease treatments. The presence of transglutaminase induced also an enhancement in film mechanical resistance and a reduction in their deformability. Finally, the barrier efficiency toward oxygen and carbon dioxide was found to be markedly improved in the cross-linked films which showed also a lower permeability to water vapor. Some potential practical applications of transglutaminase-treated chitosan-whey protein films are suggested
Effects of an aquagym training in postmepausal women
Los cambios en la composiciĂłn corporal de mujeres posmenopáusicas, principalmente, el aumento del tejido adiposo visceral y abdominal, son indicadores de enfermedades metabĂłlicas y cardiovasculares. Veintiuna mujeres posmenopáusicas participaron en un programa de 16 semanas de clases de Aquagym. Las variables analizadas fueron la circunferencia de cintura (CCi), la circunferencia de cadera (CCa), el Ăndice cintura-cadera (ICC), el diámetro sagital abdominal (DAS) y el tejido adiposo visceral (TAV). El tratamiento estadĂstico empleado fue una prueba t para comparar entre los grupos y el test de Goodman para analizar las alteraciones en la clasificaciĂłn cualitativa del ICC. Se han obtenido reducciones significativas (p≤0,05) para todas las variables medidas despuĂ©s de la intervenciĂłn de ejercicio. El programa de Aquagym fue capaz de reducir el tejido adiposo visceral y abdominal, además de disminuir el riego para el desarrollo de enfermedades de enfermedades metabĂłlicas y cardiovasculares, constituyendo una estrategia eficaz para tratar la obesidad central.Changes in body composition in postmenopausal women and increased abdominal visceral adipose tissue are markers of metabolic and cardiovascular diseases. Twenty-one postmenopausal women participated in Aquagym's classes during 16 weeks. The analyzed variables included measures of waist circumference (WC), hip circumference (HC), waist-hip ratio (ICC), abdominal sagittal diameter (ASD) and intra-abdominal adipose tissue (IAAT). Statistical treatment was used as the paired t test for comparisons between the groups before and after Aquagym practice and Goodman`s test to analyze the changes in the qualitative classification of the ICC. Significant reductions (p≤0.05) have been found for all measured variables. Aquagym program was able to reduce the abdominal visceral adipose tissue, thus decreasing the risk of developing metabolic and cardiovascular diseases, constituting an effective strategy to deal with central obesity
Evaluation of polygenic determinants of non-alcoholic fatty liver disease (NAFLD) by a candidate genes resequencing strategy
NAFLD is a polygenic condition but the individual and cumulative contribution of identified genes remains to be established. To get additional insight into the genetic architecture of NAFLD, GWAS-identified GCKR, PPP1R3B, NCAN, LYPLAL1 and TM6SF2 genes were resequenced by next generation sequencing in a cohort of 218 NAFLD subjects and 227 controls, where PNPLA3 rs738409 and MBOAT7 rs641738 genotypes were also obtained. A total of 168 sequence variants were detected and 47 were annotated as functional. When all functional variants within each gene were considered, only those in TM6SF2 accumulate in NAFLD subjects compared to controls (P = 0.04). Among individual variants, rs1260326 in GCKR and rs641738 in MBOAT7 (recessive), rs58542926 in TM6SF2 and rs738409 in PNPLA3 (dominant) emerged as associated to NAFLD, with PNPLA3 rs738409 being the strongest predictor (OR 3.12, 95% CI, 1.8-5.5, P 0.28 was associated with a 3-fold increased risk of NAFLD. Interestingly, rs61756425 in PPP1R3B and rs641738 in MBOAT7 genes were predictors of NAFLD severity. Overall, TM6SF2, GCKR, PNPLA3 and MBOAT7 were confirmed to be associated with NAFLD and a score based on these genes was highly predictive of this condition. In addition, PPP1R3B and MBOAT7 might influence NAFLD severity
Basil (Ocimum basilicum L.) Leaves as a Source of Bioactive Compounds
Basil (Ocimum basilicum L.) is an annual spicy plant generally utilized as a flavouring agent for food. Basil leaves also have pharmaceutical properties due to the presence of polyphenols, phenolic acids, and flavonoids. In this work, carbon dioxide was employed to extract bioactive compounds from basil leaves. Extraction with supercritical CO2 (p = 30 MPa; T = 50 °C) for 2 h using 10% ethanol as a cosolvent was the most efficient method, with a yield similar to that of the control (100% ethanol) and was applied to two basil cultivars: “Italiano Classico” and “Genovese”. Antioxidant activity, phenolic acid content, and volatile organic compounds were determined in the extracts obtained by this method. In both cultivars, the supercritical CO2 extracts showed antiradical activity (ABTS●+ assay), caffeic acid (1.69–1.92 mg/g), linalool (35–27%), and bergamotene (11–14%) contents significantly higher than those of the control. The polyphenol content and antiradical activity measured by the three assays were higher in the “Genovese” cultivar than in the “Italiano Classico” cultivar, while the linalool content was higher (35.08%) in the “Italiano Classico” cultivar. Supercritical CO2 not only allowed us to obtain extracts rich in bioactive compounds in an environmentally friendly way but also reduced ethanol consumption
Clostridium difficile Toxins A and B: Insights into Pathogenic Properties and Extraintestinal Effects
Clostridium difficile infection (CDI) has significant clinical impact especially on the elderly and/or immunocompromised patients. The pathogenicity of Clostridium difficile is mainly mediated by two exotoxins: toxin A (TcdA) and toxin B (TcdB). These toxins primarily disrupt the cytoskeletal structure and the tight junctions of target cells causing cell rounding and ultimately cell death. Detectable C. difficile toxemia is strongly associated with fulminant disease. However, besides the well-known intestinal damage, recent animal and in vitro studies have suggested a more far-reaching role for these toxins activity including cardiac, renal, and neurologic impairment. The creation of C. difficile strains with mutations in the genes encoding toxin A and B indicate that toxin B plays a major role in overall CDI pathogenesis. Novel insights, such as the role of a regulator protein (TcdE) on toxin production and binding interactions between albumin and C. difficile toxins, have recently been discovered and will be described. Our review focuses on the toxin-mediated pathogenic processes of CDI with an emphasis on recent studies
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