University of Extremadura

About: University of Extremadura is a education organization based out in Badajoz, Spain. It is known for research contribution in the topics: Population & Hyperspectral imaging. The organization has 7856 authors who have published 18299 publications receiving 396126 citations. The organization is also known as: Universidad de Extremadura.

An in-depth view of the microscopic dynamics of ising spin glasses at fixed temperature

Abstract: Using the special-purpose computer Janus, we follow the nonequilibrium dynamics of the Ising spin glass in three dimensions for eleven orders of magnitude. The use of integral estimators for the coherence and correlation lengths allows us to study dynamic heterogeneities and the presence of a replicon mode and to obtain safe bounds on the Edwards-Anderson order parameter below the critical temperature. We obtain good agreement with experimental determinations of the temperature-dependent decay exponents for the thermoremanent magnetization. This magnitude is observed to scale with the much harder to measure coherence length, a potentially useful result for experimentalists. The exponents for energy relaxation display a linear dependence on temperature and reasonable extrapolations to the critical point. We conclude examining the time growth of the coherence length, with a comparison of critical and activated dynamics.

Interethnic and intraethnic variability of NAT2 single nucleotide polymorphisms.

Abstract: Genetic polymorphisms of human arylamine N-acetyltransferase 2 (NAT2) are responsible for interindividual variation in the acetylation of numerous drugs and in the transformation of aromatic and heterocyclic amines into carcinogenic intermediates. Although large interethnic variability in the frequency for NAT2 variant alleles has been reported, comparison of allele frequencies is hampered by differences in the criteria for the assignment of allelic variants. To avoid such sources of bias, in this review we analyze the occurrence of both interethnic and intraethnic variability for the seven commonest single nucleotide polymorphisms (SNP) in the NAT2 gene by using raw SNP data instead of inferred haplotypes. Besides the large interethnic variability observed for all SNPs except C282T, intraethnic variability for NAT2 SNPs was identified for the SNPs G191A among Caucasians (p<0.0001), T341C among Oriental (p<0.001) or African individuals (p<0.012), C481T among Oriental (p<0.001) or African individuals (p<0.001), and G590A among Oriental individuals (p<0.001). In contrast, no major intraethnic differences were identified for the SNPs C282T, A806G or G857A. Intraethnic variability may have relevant clinical implications. For instance, case-control NAT2 studies should not be extrapolated from one Oriental population to another. Nonsynonymous SNPs occur in 32% of alleles in Japanese individuals and in 47% of alleles in Chinese individuals, therefore the frequency of adverse effects and cancer related to slow acetylation is expected to be higher in individuals with Chinese descent than in those with Japanese descent. Intraethnic variability reinforces the need for proper selection of control subjects and points against the use of surrogate control groups for studies involving association of NAT2 alleles with adverse drug effects or spontaneous diseases.

Protein carbonylation and water-holding capacity of pork subjected to frozen storage: effect of muscle type, premincing, and packaging.

Abstract: The present work aimed to study the relationship between protein carbonylation and the loss of water-holding capacity (WHC) occurring during frozen storage of porcine muscles. Pork samples corresponding to two different muscle types, glycolytic M. longissimus dorsi (LD) and oxidative M. psoas major (PM), and subjected to two different premincing, minced (MINCED) and intact pork pieces (INTACT), and packaging, vacuum packaged (VACUUM) and packed in oxygen-permeable bags (OXYGEN), procedures were frozen (-18 °C/12 weeks) and analyzed at sampling times upon thawing (weeks 1, 4, 8, and 12) for the relative amount of specific protein carbonyls, α-aminoadipic and γ-glutamic semialdehydes (AAS and GGS, respectively), and their ability to hold water using two different techniques. The formation of protein carbonyls occurred concomitantly with the loss of WHC, and both phenomena were found to be more intense in LD muscles and in MINCED and OXYGEN pork samples. The loss in WHC was from ca. 10 to 30% in 12 weeks, depending on the method of determination. Plausible mechanisms by which protein carbonylation may decrease the WHC of pork samples are thoroughly discussed in the present paper. Besides the likely impact of protein carbonylation in the water-myofibrillar protein relationships, the implication of AAS and GGS in further reactions including plausible cross-linking would explain the decrease of these semialdehydes by the end of frozen storage and would reinforce their liability in the loss of WHC of porcine muscles. The exact nature of these reactions, however, should be investigated in further studies.

The plastid ancestor originated among one of the major cyanobacterial lineages.

Abstract: Chloroplasts originate from endosymbiosis between a cyanobacterium and a eukaryotic mitochondriate ancestor. Here, the authors show that the plastid ancestor is related to a cyanobacterial lineage that include N2-fixing filamentous cyanobacteria and species with specialized nitrogen-fixing cells.