1,465 research outputs found

    The Influence of Microstructure on Hydrogen Diffusion and Embrittlement of Multiphase Fine-Grained Steels with Increased Plasticity and Strength

    Get PDF
    The influence of microstructure on hydrogen diffusion and embrittlement of multiphase fine-grained structural steels with increased plasticity and strength was studied with electrochemical experiments which provide the hydrogenation of specimens in conditions simulating practice requirements. By means of all experimental data obtained from permeation experiments, mechanical investigations, SEM and EDS analyses, TRIP steel has shown greater resistance to hydrogen embrittlement than DP steel, testified by lower index of hydrogen embrittlement, lower diffusion coefficient, less inclusions and favourable microstructure with residual austenite. Namely, the residual austenite in the aspect of hydrogen embrittlement is a favourable phase in relation to martensite, because of its higher solubility of carbon and hydrogen and lower hardness. Therefore, TRIP steel could be considered the more suitable structural material than DP steel for application in conditions where contact with hydrogen is inevitable

    A prospective analysis of the injury incidence of young male professional football players on artificial turf

    Get PDF
    Background: The effects of synthetic surfaces on the risk of injuries is still debated in literature and the majority of published data seems to be contradictory. For such reasons the understanding of injury incidence on such surfaces, especially in youth sport, is fundamental for injury prevention. Objectives: The aim of this study was to prospectively report the epidemiology of injuries in young football players, playing on artificial turfs, during a one sports season. Patients and Methods: 80 young male football players (age 16.1 ± 3.7 years; height 174 ± 6.6 cm; weight 64.2 ± 6.3 kg) were enrolled in a prospective cohort study. The participants were then divided in two groups; the first included players age ranging from 17 to 19 (OP) whereas the second included players age ranging from 13 to 16 (YP). Injury incidence was recorded prospectively, according to the consensus statement for soccer. Results: A total of 107 injuries (35 from the OP and 72 from the YP) were recorded during an exposure time of 83.760 hours (incidence 1.28/1000 per player hours); 22 during matches (incidence 2.84/1000 per player hours, 20.5%) and 85 during training (incidence 1.15/1000 per player hours, 79.5%). Thigh and groin were the most common injury locations (33.6% and 21.5%, respectively) while muscle injuries such as contractures and strains were the most common injury typologies (68.23%). No statistical differences between groups were displayed, except for the rate of severe injuries during matches, with the OP displaying slightly higher rates compared to the YP. Severe injuries accounted for 10.28% of the total injuries reported. The average time lost due to injuries was 14 days. Re-injuries accounted for 4.67% of all injuries sustained during the season. Conclusions: In professional youth soccer injury rates are reasonably low. Muscle injuries are the most common type of injuries while groin and thigh the most common locations. Artificial turf pitches don’t seem to contribute to injury incidence in young football players

    Lens epithelial cell apoptosis and intracellular Ca(2+) increase in the presence of xanthurenic acid

    Get PDF
    BACKGROUND: Xanthurenic acid is an endogenous product of tryptophan degradation by indoleamine 2,3-dioxygenase (IDO). We have previously reported that IDO is present in mammalian lenses, and xanthurenic acid is accumulated in the lenses with aging. Here, we studied the involvement of xanthurenic acid in the human lens epithelial cell physiology. METHODS: Human lens epithelial cells primary cultures were used. Control cells, and cells in the presence of xanthurenic acid grow in the dark. Western blot analysis and immunofluorescence studies were performed. RESULTS: In the presence of xanthurenic acid human lens epithelial cells undergo apoptosis-like cell death. In the control cells gelsolin stained the perinuclear region, whereas in the presence of 10 μM xanthurenic acid gelsolin is translocated to the cytoskeleton, but does not lead to cytoskeleton breakdown. In the same condition caspase-3 activation, and DNA fragmentation was observed. At low (5 to 10 μM) of xanthurenic acid concentration, the elongation of the cytoskeleton was associated with migration of mitochondria and cytochrome c release. At higher concentrations xanthurenic acid (20 μM and 40 μM) damaged mitochondria were observed in the perinuclear region, and nuclear DNA cleavage was observed. We observed an induction of calpain Lp 82 and an increase of free Ca(2+) in the cells in a xanthurenic acid concentration-dependent manner. CONCLUSIONS: The results show that xanthurenic acid accumulation in human lens epithelial cells disturbs the normal cell physiology and leads to a cascade of pathological events. Xanthurenic acid induces calpain Lp82 and caspases in the cells growing in the dark and can be involved in senile cataract development

    Analisis Keragaman Genetik Pada Ikan Kerapu Macan (Epinephelus Fuscoguttatus) Yang Tahan Terhadap Penyakit Yang Disebabkan Bakteri Vibrio Alginolyticus

    Full text link
    The research was purposed to analyse genetic similarity of tiger grouper (Epinephelus fuscoguttatus) inorder to select grouper that was resistant to Vibrio alginolyticus. In this study, fish were challenged with Vibrioalginolyticus and genetic similarity was examined by a PCR-RAPD method. Eight RAPD primers were used forPCR-RAPD analysis. The results showed that only three primers of RAPD primer (YNZ-22, UBC-456, danUBC-457) generated high number of RAPD fragments. The resistant group of tiger groupers generated higherpolymorph RAPD fragments than the susceptible groups. RAPD primer YNZ-22 and UBC-457 generated 82 %and 71 % of RAPD polymorph fragments from resistant group of fish and 71% and 60 % from susceptiblegroups, respectively. Primer YNZ-22 is a best genetic marker to analyse genetic similarity of tiger groupersproduced specific marker ranging from 1,2-2,0 kb. Genetic distances between the population of resistant fishand population of susceptible fish was 0.5091 and between individual of the resistant fish and susceptible fishwas 0.7032

    non-linear relationships in children 6-10 years

    Get PDF
    Background: Given the concern for health?related consequences of an elevated body mass index (BMI; obesity), the potential consequences of a low BMI in children are often overlooked. The purpose was to evaluate the relationship between the BMI across its entire spectrum and motor coordination (MC) in children 6?10 years. Methods: Height, weight, and MC (K?rperkoordinationstest f?r Kinder, KTK test battery) were measured in 1,912 boys and 1,826 girls of 6?10 years of age. BMI (kg/m2) was calculated. KTK scores for each of the four tests were also converted to a motor quotient (MQ). One?way ANOVA was used to test differences in the BMI, individual test items, and MQ among boys and girls within age groups. Sex?specific quadratic regressions of individual KTK items and the MQ on the BMI were calculated. Girls and boys were also classified into four weight status groups using International Obesity Task Force criteria: thin, normal, overweight, and obese. Differences in specific test items and MQ between weight status groups were evaluated by age group in each sex. Results: Thirty?one percent of the sample was overweight or obese, whereas 5% was thin. On average, normal weight children had the highest MQ in both sexes across the age range with few exceptions. Overweight/obese children had a lower MQ than normal weight and thin children. The quadratic regression lines generally presented an inverted parabolic relationship between the BMI and MC and suggested a decrease in MC with an increase in the BMI. Conclusion: In general, BMI shows a curvilinear, inverted parabolic relationship with MC in children 6?10 years.4811-99FE-2ECD | Luis Paulo Rodriguesinfo:eu-repo/semantics/publishedVersio

    Limits on the early afterglow phase of gamma-ray burst sources from TAROT-1

    Get PDF
    The T\'elescope \`a Action Rapide pour les Objets Transitoires (TAROT-1) has as prime objective the observation of the prompt and delayed emission of cosmic gamma-ray bursts (GRBs). We have performed a search for optical emission from 6 GRBs detected by BATSE. The positioning error circle was fully covered within typically thirty minutes after the trigger. No detection of the early afterglow phase was made, and magnitude limits in the range of mR=1315 \mathrm{m}_{\mathrm{R}} = 13-15 were estimated using 20s exposures. These limits are compared to optical afterglow data obtained in later phases and the results are interpreted in terms of source distances. They correspond to a median redshift of z = 0.5. With HETE-2 and the planned instrument upgrade, TAROT-1 will be able to detect the early optical emission of GRBs up to a redshift of the order of 5.Comment: 7 pages, accepted in Astronomy and Astrophysic

    Social physique anxiety and physical activity in early adolescent girls : the influence of maturation and physical activity motives

    Get PDF
    This study considered the influence of maturation on social physique anxiety (SPA), the relationship between SPA and current and future physical activity (PA) levels and the influence of motives for physical activity on this relationship in early adolescent girls (n=162; mean age=11.80±0.33 years). Participants completed the Pubertal Development Scale, the modified Social Physique Anxiety Scale and the Motives for Physical Activity Scale at baseline and the Physical Activity Questionnaire for Older Children at baseline and 6 months later. The girls became less active across the 6 months and girls in the early stages of maturation had significantly lower SPA than the girls in the middle and late stages of maturation. SPA was not related to current or future physical activity in the sample as a whole. Cluster analysis identified four groups with different motive profiles and the High Appearance and Fitness group demonstrated a moderate negative relationship between SPA and PA at phase 1, whereas the other groups did not. These findings indicate that SPA may increase with maturation and the relationship between SPA and PA is dependent on reasons for being active. For girls who are motivated to be active primarily by body-related reasons SPA is likely to lead to lower levels of PA

    Large-Amplitude Ultraviolet Variations in the RR Lyrae Star ROTSE-I J143753.84+345924.8

    Full text link
    The NASA Galaxy Evolution Explorer (GALEX) satellite has obtained simultaneous near and far ultraviolet light curves of the ROTSE-I Catalog RR Lyrae ab-type variable star J143753.84+345924.8. A series of 38 GALEX Deep Imaging Survey observations well distributed in phase within the star's 0.56432d period shows an AB=4.9mag variation in the far UV (1350-1750A) band and an AB=1.8mag variation in the near UV (1750-2750A) band, compared with only a 0.8mag variation in the broad, unfiltered ROTSE-I (4500-10000A) band. These GALEX UV observations are the first to reveal a large RR Lyrae amplitude variation at wavelengths below 1800A. We compare the GALEX and ROTSE-I observations to predictions made by recent Kurucz stellar atmosphere models. We use published physical parameters for the comparable period (0.57433d), well-observed RR Lyrae star WY Antliae to compute predicted FUV, NUV, and ROTSE-I light curves for J143753.84+345924.8. The observed light curves agree with the Kurucz predictions for [Fe/H]=-1.25 to within AB=0.2mag in the GALEX NUV and ROTSE-I bands, and within 0.5mag in the FUV. At all metallicities between solar and one hundredth solar, the Kurucz models predict 6-8mag of variation at wavelengths between 1000-1700A. Other variable stars with similar temperature variations, such as Cepheids, should also have large-amplitude FUV light curves, observable during the ongoing GALEX imaging surveys.Comment: This paper will be published as part of the Galaxy Evolution Explorer (GALEX) Astrophysical Journal Letters Special Issue. Links to the full set of papers will be available at http:/www.galex.caltech.edu/PUBLICATIONS after November 22, 200

    The GALEX UV luminosity function of the cluster of galaxies Abell 1367

    Full text link
    We present the GALEX NUV (2310 A) and FUV (1530 A) galaxy luminosity functions of the nearby cluster of galaxies A1367 in the magnitude range -20.3< M_AB < -13.3. The luminosity functions are consistent with previous (~ 2 mag shallower) estimates based on the FOCA and FAUST experiments, but display a steeper faint-end slope than the GALEX luminosity function for local field galaxies. Using spectro-photometric optical data we select out star-forming systems from quiescent galaxies and study their separate contributions to the cluster luminosity function. We find that the UV luminosity function of cluster star-forming galaxies is consistent with the field. The difference between the cluster and field LF is entirely due to the contribution at low luminosities (M_AB >-16 mag) of non star-forming, early-type galaxies that are significantly over dense in clusters.Comment: 4 pages, 4 figures, 1 table. Accepted for publication in Astrophysical Journal Letter
    corecore