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.

Enhanced activity and reusability of TiO2 loaded magnetic activated carbon for solar photocatalytic ozonation

Abstract: Magnetically separable photocatalysts with high activity under solar illumination were successfully synthesized from a commercial meso-to-microporous activated carbon. First magnetite and then titania (anatase) were deposited onto the activated carbon support by impregnation and sol–gel methods, respectively. Various catalyst samples were prepared with different iron and titania contents. The synthesized photocatalysts were characterized by nitrogen adsorption, XRD, SEM, EDX, XPS and SQUID magnetometer. Photocatalytic performance of some selected samples was examined under various irradiation conditions in the wavelength ranges of 300–800 nm, 320–800 nm and 390–800 nm. Metoprolol tartrate (MTP) in aqueous solution (50 mg L −1 ) was chosen as target compound for catalytic activity tests. The most efficient catalyst had TiO 2 and Fe mass compositions of 64 wt% and 9 wt%, respectively. It showed high activity in photocatalytic ozonation with complete removal of MTP in less than 2 h reaction time and 85% mineralization after 5 h. This catalyst was also easily separable due to its developed magnetic properties. Catalyst reusability and stability was proved to be rather good after completing a series of 10 consecutive photocatalytic ozonation runs.

Age-related change in breeding performance in early life is associated with an increase in competence in the migratory barn swallow Hirundo rustica

Abstract: 1. We investigated age-related changes in two reproductive traits (laying date and annual fecundity) in barn swallows Hirundo rustica L. using a mixed model approach to di-stinguish among between- and within-individual changes in breeding performance with age. 2. We tested predictions of age-related improvements of competence (i.e. constraint hypothesis) and age-related progressive disappearance of poor-quality breeders (i.e. selection hypothesis) to explain age-related increase in breeding performance in early life. 3. Reproductive success increased in early life, reaching a plateau at middle age (e.g. at 3 years of age) and decreasing at older age (> 4 years). Age-related changes in breeding success were due mainly to an effect of female age. 4. Age of both female and male affected timing of reproduction. Final linear mixed effect models (LME) for laying date included main and quadratic terms for female and male age, suggesting a deterioration in reproductive performance at older age for both males and females. 5. We found evidence supporting the constraints hypothesis that increases in competence within individuals, with ageing being the most probable cause of the observed increase in breeding performance with age in early life. Two mechanisms were implicated: (1) advance in male arrival date with age provided middle-aged males with better access to mates. Yearling males arrived later to the breeding grounds and therefore had limited access to high-quality mates. (2) Breeding pairs maintaining bonds for 2 consecutive years (experienced pairs) had higher fecundity than newly formed inexperienced breeding pairs. 6. There was no support for the selection hypothesis because breeding performance was not correlated with life span. 7. We found a within-individual deterioration in breeding and migratory performance (arrival date) in the oldest age-classes consistent with senescence in these reproductive and migratory traits.

Mitochondrial ATP is required for the maintenance of membrane integrity in stallion spermatozoa, whereas motility requires both glycolysis and oxidative phosphorylation.

Abstract: To investigate the hypothesis that oxidative phosphorylation is a major source of ATP to fuel stallion sperm motility, oxidative phosphorylation was suppressed using the mitochondrial uncouplers CCCP and 2,4,-dinitrophenol (DNP) and by inhibiting mitochondrial respiration at complex IV using sodium cyanide or at the level of ATP synthase using oligomycin-A. As mitochondrial dysfunction may also lead to oxidative stress, production of reactive oxygen species was monitored simultaneously. All inhibitors reduced ATP content, but oligomycin-A did so most profoundly. Oligomycin-A and CCCP also significantly reduced mitochondrial membrane potential. Sperm motility almost completely ceased after the inhibition of mitochondrial respiration and both percentage of motile sperm and sperm velocity were reduced in the presence of mitochondrial uncouplers. Inhibition of ATP synthesis resulted in the loss of sperm membrane integrity and increased the production of reactive oxygen species by degenerating sperm. Inhibition of glycolysis by deoxyglucose led to reduced sperm velocities and reduced ATP content, but not to loss of membrane integrity. These results suggest that, in contrast to many other mammalian species, stallion spermatozoa rely primarily on oxidative phosphorylation to generate the energy required for instance to maintain a functional Na+/K+ gradient, which is dependent on an Na+-K+ antiporter ATPase, which relates directly to the noted membrane integrity loss. Under aerobic conditions, however, glycolysis also provides the energy required for sperm motility.

Interethnic differences in drug metabolism: influence of genetic and environmental factors on debrisoquine hydroxylation phenotype.

Abstract: Genetic and environmental factors are determinants of the interindividual and interethnic variability in drug metabolism. The metabolism of several important drugs (e.g. haloperidol) cosegregates with that of debrisoquine. Thus, interethnic differences in debrisoquine hydroxylation polymorphism (CYP2D6) might be partly responsible for the variation in haloperidol disposition between races. The influence of tobacco, ethanol, caffeine, gender, and oral contraceptive use on the debrisoquine metabolic ratio (MR) has been analyzed in 633 Spanish healthy volunteers. MR was also determined in panels of healthy volunteers. 18 smokers were studied during a tobacco abstinence period, and 31 women three times during the same menstrual cycle. Among EMs, debrisoquine MR was significantly (P < 0.05) lower during smoking cessation (mean antilog +/- SD, 0.48 +/- 0.29) compared to a smoking period (0.61 +/- 0.23). During the lutheal phase of the menstrual cycle, debrisoquine MR was also significantly (P < 0.01) lower (0.33 +/- 0.41) compared to the ovulatory-phase (0.41 +/- 0.34) and the phase before ovulation (0.44 +/- 0.36). Among EMs, it is suggested that debrisoquine MR may be modified by tobacco smoking and sexual hormones. The clinical relevance of these findings remains unclear.

Glutathione S-transferases mu 1, theta 1, pi 1, alpha 1 and mu 3 genetic polymorphisms and the risk of colorectal and gastric cancers in humans.

Abstract: Introduction: Glutathione S-transferases (GSTs) are considered to be cancer susceptibility genes as they play a role in the detoxification of carcinogenic species. This study aimed to elucidate the influence of several GST polymorphisms on colorectal and gastric cancer risk. Patients and methods: GST μ1 (GSTM1), θ1 (GSTT1), π1 (GSTP1), α1 (GSTA1) and μ3 (GSTM3) genotypes were determined in 144 colorectal cancer patients, 98 gastric cancer patients and 329 healthy control individuals. Results: Colorectal cancer: the risk is greater for carriers of the GSTM1 null genotype (odds ratio [OR] = 1.91, 95% confidence interval [CI] = 1.25–2.91), for carriers of the GSTT1 null genotype (OR = 3.62, 95% CI = 2.34–5.62), and for simultaneous carriers of both GSTM1 and GSTT1 null genotypes (OR = 4.98, 95% CI = 2.77–9.00). Carriers of the GSTP1 104 Val/Val genotype are at a lower risk (OR = 0.31, 95% CI = 0.09–0.88). Among carriers of the GSTP1 Ile/Ile genotype, smoking increases the risk compared with nonsmoking (OR = ...