Diseño, fabricación y aplicaciones analíticas de nanocelulosa y sus híbridos

El gran avance nanotecnológico que ha experimentado la Química Analítica en los últimos años ha sido un indicador del grado de bienestar de la sociedad. La multidisciplinaridad de la Nanociencia y Nanotecnología ha sido esencial para el avance de los métodos y herramientas analíticas, así como para llevar a cabo la automatización, simplificación y miniaturización de los procesos analíticos integrados en los laboratorios [1]. En este campo, son muchos los nanomateriales explorados por sus propiedades excepcionales (ópticas, eléctricas, magnéticas) como sensores y sorbentes así como su amplio rango de aplicación de interés medioambiental o en bienes de consumo, cosmética, agroalimentación, entre otros. Sin embargo, la nanocelulosa no se ha explorado en química analítica aun siendo postulada como uno de los nanomateriales emergentes del siglo XXI, debido a su carácter biodegradable y su abundancia en la naturaleza, así como a otras fascinantes propiedades que le confieren un sinfín de aplicaciones. No cabe duda que en la búsqueda de los nanomateriales del futuro la nanocelulosa revolucionará las industrias electrónica, textil, farmacéutica y la energética, por su producción a gran escala con bajo coste a partir de un recurso natural renovable. Teniendo en cuenta lo anteriormente expuesto, la Tesis Doctoral tiene como objetivo general el estudio de la nanocelulosa en química analítica, centrándonos en el diseño de nanofibras de celulosa como herramienta en la mejora de los procesos analíticos, así como en la separación de productos farmacéuticos y otros

QUANTIFYING IMPACTS DURING BEAM AND FLOOR TRAINING IN PREADOLESCENT GIRLS FROM TWO STREAMS OF ARTISTIC GYMNASTICS

The primary aim of this study was to determine the effects of participation level (international and national), apparatus (beam and floor) and training phase (precompetition and competition) on estimates of training load in a convenient sample of gymnasts aged 7 to 13 years. Video analysis of training sessions along with accelerometer and force platform (500 Hz) peak ground reaction force data were used to establish differences between key gymnastic-specific and non-gymnastic-specific variables. International level gymnasts demonstrated higher incidence in hours of training, number of observed impacts, markers of the quality of periodised training program and lower relative injury rates. Marked differences were also observed between the two training phases. The demand for injury prevention strategies may be higher at the national level of gymnastics training

Low Levels of after School-Hours Social Interaction and Physical Activity of 5-7 Year Olds

As part of a cluster randomized controlled trial (Bundy et al., 2017), the after school-hours activities of 5-7 year old children were recorded by parents and other adult carers on four consecutive weekdays between 3:30pm-7:00pm. Records of time use showed most time was spent indoors in activities involving low levels of physical activity. The most-frequently-recorded activity was screen time, accounting for approximately one quarter of all activities. Higher levels of physical activity were reported when children were outdoors (19.5% of time) and/or with peers (9.58%). If an adult was present, highest activity levels of children occurred when the child was with a teacher/carer (6.07%). Although concern is frequently raised about children spending too much time in organized activities, these structured forms of out-of-school choices accounted for only 8.09% of recordings. The results of the current study strengthen the evidence base, supporting the need to optimise out-ofschool times with more developmentally important social and physical contexts. We discuss ways in which context may support or inhibit opportunities physical activity in after school-hours activities

A Randomized Controlled Trial of Whole Body Vibration Exposure on Markers of Bone Turnover in Postmenopausal Women

Purpose. To examine the effects of two doses of low-frequency (12 Hz), low-magnitude (0.3 g), whole body vibration on markers of bone formation and resorption in postmenopausal women. Methods. Women were recruited and randomized into a sham vibration control group, one time per week vibration group (1×/week), or three times per week vibration group (3×/week). Vibration exposure consisted of 20 minutes of intermittent vibration for the 1×/week and 3×/week groups, and sham vibration (<0.1 g) for the control group for eight weeks. Double-blinded primary outcome measures were urine markers of bone resorption: N-telopeptide X normalised to creatinine (NTx/Cr) and bone formation: bone-specific alkaline phosphatase (ALP). Results. Forty-six women (59.8 ± 6.2 years, median 7.3 years since menopause) were enrolled. NTx/Cr was significantly reduced (34.6%) in the 3×/wk vibration group but not in the 1×/wk vibration group compared with sham control (P < .01) group. No effect of time or group allocation was observed on the bone formation marker ALP (P = .27). Conclusion. We have shown for the first time that low-frequency, low-magnitude vibration 3×/week for eight weeks in postmenopausal women results in a significant reduction in NTx/Cr, a marker of bone resorption, when compared with sham vibration exposure

Outcomes and costs of primary care surveillance and intervention for overweight or obese children: the LEAP 2 randomised controlled trial

Objective To determine whether ascertainment of childhood obesity by surveillance followed by structured secondary prevention in primary care improved outcomes in overweight or mildly obese children

The Sydney Playground Project: popping the bubblewrap - unleashing the power of play: a cluster randomized controlled trial of a primary school playground-based intervention aiming to increase children\u27s physical activity and social skills

Background In the Westernised world, numerous children are overweight and have problems with bullying and mental health. One of the underlying causes for all three is postulated to be a decrease in outdoor free play. The aim of the Sydney Playground Project is to demonstrate the effectiveness of two simple interventions aimed to increase children\u27s physical activity and social skills. Methods/Design This study protocol describes the design of a 3-year cluster randomised controlled trial (CRCT), in which schools are the clusters. The study consists of a 13-week intervention and 1 week each of pre-and post-testing. We are recruiting 12 schools (6 control; 6 intervention), with 18 randomly chosen participants aged 5 to 7 years in each school. The two intervention strategies are: (1) Child-based intervention: Unstructured materials with no obvious play value introduced to the playground; and (2) Adult-based intervention: Risk reframing sessions held with parents and teachers with the aim of exploring the benefits of allowing children to engage in activities with uncertain outcomes. The primary outcome of the study, physical activity as measured by accelerometer counts, is assessed at baseline and post-intervention. Additional assessments include social skills and interactions, self-concept, after school time use and anthropometric data. Qualitative data (i.e., transcriptions of audio recordings from the risk reframing sessions and of interviews with selected teacher and parent volunteers) are analysed to understand their perceptions of risk in play. The control schools have recess as usual. In addition to outcome evaluation, regular process evaluation sessions are held to monitor fidelity to the treatment. Discussion These simple interventions, which could be adopted in every primary school, have the potential of initiating a self-sustaining cycle of prevention for childhood obesity, bullying and mental ill health

The role of protected areas in the avoidance of anthropogenic conversion in a high pressure region : a matching method analysis in the core region of the brazilian cerrado

Global efforts to avoid anthropogenic conversion of natural habitat rely heavily on the establishment of protected areas. Studies that evaluate the effectiveness of these areas with a focus on preserving the natural habitat define effectiveness as a measure of the influence of protected areas on total avoided conversion. Changes in the estimated effectiveness are related to local and regional differences, evaluation methods, restriction categories that include the protected areas, and other characteristics. The overall objective of this study was to evaluate the effectiveness of protected areas to prevent the advance of the conversion of natural areas in the core region of the Brazil’s Cerrado Biome, taking into account the influence of the restriction degree, governmental sphere, time since the establishment of the protected area units, and the size of the area on the performance of protected areas. The evaluation was conducted using matching methods and took into account the following two fundamental issues: control of statistical biases caused by the influence of covariates on the likelihood of anthropogenic conversion and the non-randomness of the allocation of protected areas throughout the territory (spatial correlation effect) and the control of statistical bias caused by the influence of auto-correlation and leakage effect. Using a sample design that is not based on ways to control these biases may result in outcomes that underestimate or overestimate the effectiveness of those units. The matching method accounted for a bias reduction in 94–99% of the estimation of the average effect of protected areas on anthropogenic conversion and allowed us to obtain results with a reduced influence of the auto-correlation and leakage effects. Most protected areas had a positive influence on the maintenance of natural habitats, although wide variation in this effectiveness was dependent on the type, restriction, governmental sphere, size and age group of the unit

Adaptive skeletal responses to mechanical loading during adolescence

Adolescence, defined as the period between puberty and maturity, provides a window of opportunity for positive skeletal adaptations to mechanical loading unlike any other period in life. Age-related bone loss highlights the importance of accumulating sufficient bone mass during formative years. Adolescents who regularly engage in weight-bearing mechanical loading appear advantaged in site-specific markers of bone mass. The positive influence of physical activity on bone mineral accrual during growth has been extensively studied; however, few studies have examined skeletal responses to mechanical loading during adolescence. Weight-bearing physical activity, particularly high-impact sports such as gymnastics, is recognised as being more osteogenic than weight-supported activities. Unilateral loading activities such as tennis or squash provide a direct comparison of skeletal response without sampling bias or genetic confounding. Intervention and longitudinal studies show evidence of positive skeletal adaptations; however, sustainability of skeletal advantages remains unclear. Limitations inherent with single-plane dual x-ray absorptiometry technology are well recognised. The integration of densitometric data with structural responses to mechanical loading using 3-dimensional imaging technologies such as peripheral quantitative computed tomography and magnetic resonance imaging appears vital to enhancing our understanding of adolescent musculoskeletal health. The framework of the human skeleton provides protection of internal organs, support against gravity, a lever system enabling movement and a reserve of ions for the maintenance of serum homeostasis. Active adolescents require a skeletal system with a composition (material properties) and organisation (structural properties) to accommodate functional demands of intense physical activity within a lightweight design facilitating energy-saving locomotion.[1] Peak bone mass reflects the maximal lifetime amount of bone mineral accrued in individual bones and the whole skeleton.[2] Peak bone mass value is a consequence of net accrual of bone during childhood and the balance between accrual and resorption in adulthood.[3] Theoretically, because bone loss occurs with aging, people who acquire maximal bone mass in their early years should be at a reduced risk of skeletal fragility and fracture in later life. Agreement on the age at which peak bone mass is achieved remains illusive and site specific.[2,4, 5, 6, 7, 8] Genetics determine the basic morphology of the skeleton, but final bone mass and architecture are modulated by adaptive mechanisms sensitive to mechanical loading.[9] Pioneer research in loading conducted by Wolff (1882) was the first to document changes in bone mass that accompany different mechanical loadings. Internal architecture and external structure alter as a consequence of primary stimuli from mechanical loading