Television watching, videogames, and excess of body fat in Spanish adolescents: the AVENA study

OBJECTIVE: We assessed the individual association of sedentary behaviors with the risk of overweight and excess body fat (overfat) in adolescents. METHODS: A representative sample (1960 subjects, 1012 males, age 13-18.5 y) of Spanish adolescents was studied within the framework of the Alimentación y Valoración del Estado Nutricional de los Adolescentes (AVENA) study. Television (TV) watching, videogame and computer usage, doing homework, and the way students got to school, physical activity, and socioeconomic status were analyzed. Anthropometrics were measured to describe overweight (International Obesity Task Force cutoffs for body mass index) and overfat (body fat percentage >85th percentile). RESULTS: When all subjects were considered as an entire group, the overweight risk increased by 15.8% (P < 0.05) per increasing hour of TV watching. The overweight risks decreased by 32.5% in females, 22% per increasing year of age, and 12.5% by increasing socioeconomic status by 1 U (all Ps < 0.05). The obesity risks decreased with age by 17.8% per year in males and 27.1% in females (both Ps < 0.05). The overfat risks increased by 26.8% and 9.4% per increasing hour of TV and weekend videogame usage, respectively (both Ps < 0.05). In males, the overfat risk increased by 21.5% per increasing hour in weekend videogame usage (P < 0.05). Each hour of TV use increased the overfat risks by 22% in males and 28.3% in females (both Ps < 0.05). CONCLUSIONS: Time spent watching TV increased the risk of overweight and obesity in Spanish adolescents, but the effect was influenced by age, sex, and socioeconomic status. Moreover, an excess of body fat was more directly explained by the time spent watching TV and playing videogames during the weekend.     

Determination of Clara cell protein urinary elimination as a marker of tubular dysfunction

Clara cell 16-kDa protein (CC16) is a protein expressed primarily by the bronchial cells. It is rapidly eliminated by glomerular filtration, reabsorbed almost entirely, and catabolized in proximal tubule cells. To date, normal values for urinary CC16 in healthy children have not been determined. We have studied 63 pediatric patients (mean age 8.17 ± 3.91 years) and 31 healthy children (control group; mean age 8.83 ± 3.65 years). In the control group, the CC16/creatinine ratio was 1.22 ± 1.52 μg/g. In 16 out of 31 control children, the value of the ratio was zero. Fourteen patients (22.2%) showed a high CC16/creatinine ratio; in contrast, among these same patients, the ratio N-acetyl-β-d-glucosaminidase (NAG)/creatinine was elevated in seven cases (11.1%) and the ratio β2-microglobulin/creatinine was elevated in seven cases (11.1%). The three parameters were in agreement in 51 patients (80.9%). Among the patients, the CC16/creatinine ratio was correlated with both the β2-microglobulin/creatinina ratio (r = 0.76, P < 0.001) and the NAG/creatinine ratio (r = 0.6, P < 0.001). Our findings indicate that CC16 is a good marker of proximal tubular function in childhood. The highest observed values were in children with proximal tubulopathies, in children with chronic renal failure, and in those treated with cyclosporine.     

Multicriteria optimal operation of a microgrid considering risk analysis,renewable resources,and model predictive control

This paper proposes an optimal power dispatch by taking into account risk management and renewable resources. In particular, it examines how control engineering and risk management techniques can be applied in the field of power systems through their use in the design of risk-based model predictive controllers. To this end, this paper proposes a two-layer control scheme for microgrid management where both levels are based on model predictive control (MPC): the higher level is devoted to risk management while the lower layer is dedicated to power dispatching. In particular, the high-level controller is based on a risk-based approach where potential risks have been identified and evaluated. Mitigation actions are the decision variables to be optimized to reduce the consequences of risks and costs. The MPC-based algorithm decides the appropriate frequency of mitigation actions such as changes in references, constraints, and insurance contracting, by relying on a model that includes integer variables, identifiable risks, their costs, and the cost/benefit assessment of mitigating actions. On the other hand, the low-level controller drives the plant to suitable values to satisfy demands. A series of simulations on a nonlinear model of a real laboratory-scale power plant located in the facilities of the University of Seville are conducted under varying conditions to demonstrate the effectiveness of the algorithm when risks are explicitly considered.     

Influence of a nonrinse conditioner on the bond strength of brackets bonded with a resin adhesive system

The objective of this study was to compare the effect of a nonrinse conditioner (NRC) and the conventional acid-etch technique on the shear bond strength and the adhesive remnant on the tooth after debonding brackets bonded with the resin orthodontic adhesive system Transbond XT. A total of 40 human premolars were divided into group I, phosphoric Acid/Transbond XT (n = 25) and group II, NRC/ Transbond XT (n = 15). Shear bond strength was measured with a universal test machine with a crosshead speed of 1 mm/min. The adhesive remnant was quantified using image analysis equipment. Scanning electron microscope (SEM) observations were also carried out to observe enamel surfaces treated with each product. No significant differences were observed in the bond strengths of the two groups evaluated. The amount of adhesive remnant on the tooth after debonding was significantly less when conditioning the enamel with NRC compared with phosphoric acid. SEM observations showed that the NRC produced a more conservative etch pattern than phosphoric acid.