Heart rate recovery is associated with obesity traits and related cardiometabolic risk factors in children and adolescents.

BACKGROUND AND AIMS: Increased vagal activity is associated with obesity and metabolic risk in children and adolescents. The aim of the present cross-sectional study was to examine the association of parasympathetic function, as assessed by heart rate recovery (HRR) from a maximal exercise cycle-ergometer test, with obesity traits and related cardiometabolic risk factors in Spanish children and adolescents. METHODS AND RESULTS: A sample of 437 Spanish 9-year-old-children and 235 15-year-old-adolescents participated in the study. The variables measured were anthropometric characteristics (height, body mass and waist circumference) and physical activity using the Actigraph accelerometer. Additional measured outcomes included fasting insulin, triglycerides, high-density lipoprotein cholesterol (HDLc) and blood pressure. A metabolic risk score was computed as the mean of the standardised outcomes scores. The HRR was calculated as the difference between peak heart rate and heart rate 1, 3 and 5 min after cessation of the maximal ergometer test. Diastolic blood pressure was associated with all the HRR parameters in 9-year-old-girls. In 9-year-old-boys, the 3-min HRR was inversely associated with systolic blood pressure (p < 0.05) and Homeostasis Model Assessment (HOMA) (p < 0.05). Five minute HRR was inversely associated with waist circumference (p < 0.05), sum of five skinfolds (p < 0.01) and HOMA (p = 0.004). There were no significant associations in adolescents. In 9-year-old-girls, the adjusted 5-min HRR showed significant differences between quartile 2 and 4 of metabolic risk (p = 0.011). In all samples, the adjusted HRR (1-, 3- and 5-min HRR) did not show significant differences across quartiles. CONCLUSION: HRR was inversely associated with obesity traits and related cardiometabolic risk factors mainly in healthy boys.

Patterns of physical activity in Spanish children: a descriptive pilot study.

BACKGROUND: The majority of Spanish adults and children do not engage in enough physical activity to be beneficial for health. There is a need for objective and accurate assessment of the proportion of children meeting the physical activity recommendation for health. Assessing patterns of physical activity both between days (during weekdays and weekend days) and within days is of interest to improve our understanding of the variation in Spanish children's physical activity and to provide efficient intervention programmes. METHODS: A sample of 221 children: 136 9-year-old children (68 boys and 68 girls) and 85 15-year-old children (36 girls and 49 boys) from 12 urban public schools in Madrid, Spain entered the study. The variables measured were anthropometric characteristics (height, weight, body mass index) and physical activity measured during four consecutive days using the GT1M accelerometer. RESULTS: Younger children were more active and less sedentary than older ones during week and weekend days. Nine-year-old boys and girls achieved significantly (P < 0.05) more moderate to vigorous physical activity (MVPA) and significantly (P < 0.01) less sedentary time than older 15-year-old children. During weekdays more children achieved physical activity recommendations versus weekend days. Physical activity patterns analyses indicated that boys achieved relatively high values of MVPA from 1100 till 1300 h (school break) and from 1800 till 2000 h in comparison with the rest of the day. Girls were substantially different, with the 9-year-old girls having only two obvious peaks of weekday MVPA at lunch (1300) and after school (1900 h) while the adolescent girls had no clear peak of MVPA. CONCLUSIONS: Few children achieved the level of MVPA recommended for health; at particular risk were adolescent girls. More effort needs to be devoted to promoting appropriate opportunities for Spanish girls across the day and to promoting physical activity during weekends for all children.

Psychosocial and Environmental Correlates of Sedentary Behaviors in Spanish Children.

Purpose. To evaluate children's psychosocial and environmental factors associated with sedentary behavior (SB). Method. The study involved a total of 420 children (mean 9.2 years; 52.9% girls) from the community of Madrid, Spain. SB and physical activity (PA) were objectively measured using accelerometers. TV viewing and potential correlates were assessed by questionnaire. Mixed-model regression analysis, adjusted for clustering within school locations, evaluated the relation of each independent variable with SBs. Results. Girls showed higher levels of SB than boys, whereas boys reported more TV viewing (p < .001 in all cases). Regression analysis showed that MVPA levels were negatively related to objective SB measurement in both boys and girls (p < .001). Parent and friend support to PA were negatively associated with SB on weekdays in boys and girls, respectively (p < .05). In the boys' group, parental professional level was a positive predictor of SB on weekend days (p = .011). Boys with more positive neighborhood perceptions spent less time watching TV (p < .001), whereas mother's leisure-time PA level was a negative correlate of TV viewing in girls' group (p < .01). Conclusion. Different psychosocial and environmental correlates of SB were identified. Present findings are promising targets for interventions to improve children's health.

Recommended levels of physical activity to avoid adiposity in Spanish children.

UNLABELLED: What is already known about this subject There is an association between adiposity levels and physical activity guidelines for adolescents. Achieving physical activity recommendations helps adolescents to prevent obesity status. What this study adds This paper presents an association between physical activity levels and obesity status. This paper supports physical activity recommendations to avoid children's obesity levels. This paper emphasizes vigorous physical activity for this matter. BACKGROUND: There is no information about physical activity (PA) recommendations to avoid children's obesity levels and how much of vigorous PA (VPA) is included into the '60 minutes of MVPA 5 days a week' recommendation for children. OBJECTIVE: The aim of this study was to examine the association between PA and adiposity in children and to examine whether the current PA guidelines are associated with a low risk of having excess of body fat in children, with special focus on sex differences, and PA intensity. METHODS: A sample of 439 Spanish children aged 8-10 years from the European Youth Heart Study participated in the study. The variables measured were anthropometric characteristics (height, weight, body mass index [BMI], skin-folds and waist circumference) and PA was measured during 6 consecutive days using the GT1M accelerometer. RESULTS: Receiver operating characteristic analysis showed significant cut-off points associated with non-overweight: 45 min d(-1) of VPA and 67 min d(-1) of moderate-to-vigorous physical activity (MVPA) (using BMI categories); and non-fat: 41 min d(-1) of VPA and 67 min d(-1) of MVPA (using percentage of body fat) and 38 min d(-1) of VPA and 47 min d(-1) of MVPA (using waist circumference categories) for boys. For girls, the optimal cut-offs of moderate-to-vigorous activity and MVPA associated with non-overweight were 24 and 57 min d(-1) , respectively (BMI). Boys who did not meet 67 min in MVPA had an increased risk of being overweight + obese and overfat + obese (odds ratio [OR] = 2.48, 95% confidence interval [CI] = 1.36, 4.53, and OR = 2.56, 95% CI = 1.12, 5.82). CONCLUSIONS: The findings support current PA recommendations (60 min d(-1) of MVPA) to avoid excess of body fat in Spanish children. However, VPA appears to be an important component for the prevention of obesity, and our findings suggest that PA recommendations should specify the dose of VPA required for optimal health. Therefore, public health PA recommendations should incorporate specifically a greater dose of VPA into the total amount of MVPA in 8- to 10-year-old boys.

Electron energy-loss spectroscopy of V2O5 nanofibers synthesized by electro-spinning.

The dielectric properties of V2O5 nanofibers, synthesized by the electrospinning method, are studied by analyzing the low-loss region of the electron energy loss spectroscopy (EELS) in a transmission electron microscope. A comparison of experimental EELS spectra and ab initio density-functional theory calculations (WIEN2k code) within the Generalized Gradient Approximation (GGA) is presented, having found an excellent agreement between them. Although the experimental EELS has been acquired for the nanoparticles composing the fibers, and numerical calculations were carried out for bulk material, agreement between experimental and calculated results shows that no difference exists between the electronic structure in calculated bulk material and the nanoparticles. Furthermore, our results from EELS confirm that we accomplished the expected crystalline phase. The origins of interband transitions are identified in the electronic band structure by calculating the partial imaginary part of the dielectric function and the partial density of states.

Experimental and theoretical determination of the low-loss electron energy loss spectroscopy of LiMn2O4.

The dielectric properties of cubic spinel-type LiMn(2)O(4), used as cathode material in lithium ion secondary batteries, are studied by analyzing the low-loss region of the electron energy loss spectroscopy (EELS) spectrum in a transmission electron microscope. A comparison of experimental EELS spectra and ab initio density-functional theory calculations (WIEN2k code) within the generalized gradient approximation (GGA) is presented. The origins of interband transitions are identified in the electronic band structure, by calculating the partial imaginary part of the dielectric function and the partial density of states of Li, Mn and O. Good agreement with experimental spectra is observed which allowed interpreting main features of the EELS spectrum.

In situ study of the metal-insulator transition in VO2 by EELS and ab initio calculations.

Changes in the dielectric properties during the thermochromic transition of commercial VO(2) powders were determined in situ, by analyzing the low-loss region of the electron energy-loss spectroscopy (EELS) spectra in a transmission electron microscope at room temperature (insulator phase) and 100 degrees C (metallic phase). A comparison of experimental EELS spectra and ab initio density-functional theory calculations (WIEN2k code) within the generalized gradient approximation (GGA) is presented. A characteristic peak around 5.6 eV appears in the energy-loss function in metallic phase, which is absent in insulator phase. The origin of the characteristic peak is analyzed by means of energy-band structure calculations.

Mild asthma: an expert review on epidemiology, clinical characteristics and treatment recommendations.

This review is the synthesis of a working group on mild asthma. Mild asthma includes intermittent and persistent mild asthma according to the Global Initiative for Asthma (GINA) classification, and affects between 50% and 75% of asthmatic patients. Mild asthma is more frequent, more symptomatic, and less well controlled in children than in adults. Cohort studies from childhood to adulthood show that asthma severity usually remains stable over time. Nevertheless, mild asthma can lead to severe exacerbations, with a frequency ranging from 0.12 to 0.77 per patient-year. Severe exacerbations in mild asthma represent 30-40% of asthma exacerbations requiring emergency consultation. In mild asthma, inflammation and structural remodelling are constant, of varying intensity, but nonspecific. Therapy with inhaled corticosteroids (ICS) decreases bronchial inflammation, but has only a slight effect on structural remodelling, and, when stopped, inflammation immediately recurs. Permanent low-dose ICS therapy is the reference treatment for persistent mild asthma. Effectiveness is to be reassessed at 3 months, and if it is insufficient the patient is no longer considered mildly asthmatic, and treatment has to be stepped up. As mild asthma is the most frequent form of the disease, diagnosis and management require physicians' particular attention.

Prolonged moderate hyperoxia induces hyperresponsiveness and airway inflammation in newborn rats.

Bronchopulmonary dysplasia is the most common cause of chronic pulmonary disease in premature infants. Airway inflammation appears to play a major pathogenetic role together with barotrauma and oxygen toxicity. The aim of the present study was to determine the effect of a 15-d exposure to moderate hyperoxia (FiO2, 50%) on airway reactivity and inflammatory response in neonatal and adult rats. We studied in isolated tracheal rings the 1) isometric contraction to cumulative concentrations of carbachol (10(-8) to 10(-3) M); 2) epithelial, submucosal, smooth muscle, and connective tissue surface area; and 3) distribution of inflammatory cells (mastocytes, granulocytes, macrophages) by using MAb. Reactivity to carbachol was significantly increased in the hyperoxic pups, in which a 13% increase in tracheal smooth muscle surface area was observed. Type-I mast cells and macrophages (submucosa and connective tissue) and granulocytes (connective tissue) were increased in the neonatal hyperoxic group. Hyperoxia did not influence functional, morphometric, or cellular data in adult rats. In conclusion, exposure of newborn rats to moderate hyperoxia induces airway hyperresponsiveness and histologic changes similar to those reported in bronchopulmonary dysplasia. Hyperresponsiveness may be ascribed to an increase in smooth muscle related to the release of yet undetermined mediators by inflammatory cells infiltrating the airways. Lung immaturity definitely plays a role because similar alterations are not observed in adult rats.