Quick X-ray reflectivity using monochromatic synchrotron radiation for time-resolved applications.

A new technique for the parallel collection of X-ray reflectivity (XRR) data, compatible with monochromatic synchrotron radiation and flat substrates, is described and applied to the in situ observation of thin-film growth. The method employs a polycapillary X-ray optic to produce a converging fan of radiation, incident onto a sample surface, and an area detector to simultaneously collect the XRR signal over an angular range matching that of the incident fan. Factors determining the range and instrumental resolution of the technique in reciprocal space, in addition to the signal-to-background ratio, are described in detail. This particular implementation records ∼5° in 2θ and resolves Kiessig fringes from samples with layer thicknesses ranging from 3 to 76 nm. The value of this approach is illustrated by showing in situ XRR data obtained with 100 ms time resolution during the growth of epitaxial La0.7Sr0.3MnO3 on SrTiO3 by pulsed laser deposition at the Cornell High Energy Synchrotron Source (CHESS). Compared with prior methods for parallel XRR data collection, this is the first method that is both sample-independent and compatible with the highly collimated, monochromatic radiation typical of third-generation synchrotron sources. Further, this technique can be readily adapted for use with laboratory-based sources.

[Comparison of Health-related Behavior Patterns of Boys and Girls in Germany: Results of the MoMo Study]. / Vergleich gesundheitsrelevanter Verhaltensmuster von Jungen und Mädchen in Deutschland: Ergebnisse der MoMo Studie.

AIM OF THE STUDY: For optimal health promotion in adolescents, it is important to know their typical behavior patterns. The aims of this study were to identify and compare sex-specific health-related behavior patterns of adolescents in Germany. METHODS: The KiGGS Survey and the MoMo Study assessed the health behavior of 832 boys and 811 girls by means of a questionnaire. The indices physical activity, diet quality and media use were included in cluster analyses for boys and girls separately. RESULTS: For each sex, 4 clusters with similar characteristics on the three included indices were identified. However, cluster size, level of the characteristics and correlates were different in boys and girls: fewer girls showed high activity levels. Overall, physical activity and media use were less pronounced in the behavior pattern of girls. There was a stronger association of behavior patterns with socio-economic status in girls. In boys, behavior patterns were significantly associated with prevalence of overweight. CONCLUSIONS: The similar cluster solutions for boys and girls support the assumption that there are typical health-related behavior patterns among German adolescents. This finding might facilitate the precise definition of homogeneous target groups for health promotion programs. Furthermore, it seems that sex-specific foci should be set.

Age- and sex-dependent disparity in physical fitness between obese and normal weight children and adolescents.

AIM: Aim of the present study was to determine whether the association between obesity and physical fitness in children and adolescents is age- and sex-specific. METHODS: A total of 4519 children and adolescents aged 4-17 years grouped by age (4-5, 6-10, 11-13 and 14-17 years), sex and BMI (normal-weight: BMI≤90th percentile; overweight: BMI>90th percentile; adipose: BMI>97th percentile) participated in this large-scale representative cross-sectional study. Endurance, strength, flexibility and fine and gross motor coordination was measured using the following physical fitness tests: PWC170, push-ups test, standing long-jumps, side-to-side jumps, one-minute single leg stance on the dominant leg, balancing backwards on three beams of different width, lowest point reached by the fingertips while standing on a box with legs extended, reaction to colour changes of traffic light, tracing lines without touching the rim and sorting 25 pens. RESULTS: Overweight and obese boys and girls had lower physical fitness values describing endurance, strength and gross motor coordination than normal-weight boys and girls, respectively (P<0.001 for all; boys: -12% and -19%, respectively; girls: -9% and -19%, respectively). Differences in physical fitness between weight groups were greater in older groups (P<0.001). Fine motor skills and flexibility values did not differ between weight groups. CONCLUSION: The disparity in physical fitness, in particular in endurance, strength and gross motor coordination, between obese and normalweight is greater in adolescents than in children. Physical fitness programs are warranted for all overweight and obese children and adolescents but especially for overweight and obese adolescents.

[Relationship between physical activity and health in children and adolescents. Results of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS) and the "Motorik-Modul" (MoMo)]. / Zum Zusammenhang zwischen körperlicher Aktivität und Gesundheit bei Kindern und Jugendlichen. Ergebnisse des Kinder- und Jugendgesundheitssurveys (KiGGS) und des Motorik-Moduls (MoMo).

The question of whether physical activity is associated with positive aspects of health becomes increasingly more important in the light of the health status in today's children and adolescents and due to the changing lifestyle with respect to everyday activity. The German Health Interview and Examination Survey for Children and Adolescents (KiGGS) collected the first set of nationwide representative cross-sectional data to examine the relationship between health and physical activity. Taking sociodemographic parameters into consideration, the results suggest a positive association between self-estimated general health and several types of physical activity. The results vary with respect to gender and type of physical activity. For methodological reasons, causal conclusions can only be drawn after longitudinal data of the second wave of KiGGS are available.

Hyperthermal organic thin film growth on surfaces terminated with self-assembled monolayers. I. The dynamics of trapping.

We have examined the initial stages of growth of a crystalline small molecule organic thin film, diindenoperylene (DIP), on SiO(2) surfaces terminated with a series of self-assembled monolayers (SAMs). In this study we make use of supersonic molecular beam techniques to vary the incident kinetic energy of the DIP molecules, and we use in situ, real time synchrotron x-ray scattering to monitor the buildup of each molecular layer in the growing thin film. We find that the effects of the SAMs are most apparent concerning growth in the sub-monolayer regime, before the substrate is entirely covered by the DIP thin film. In this coverage regime on bare SiO(2), and SiO(2) terminated with either hexamethyldisilazane or perflurooctyltrichlorosilane the adsorption dynamics are consistent with trapping-mediated adsorption as observed in more simple systems, where the probability of adsorption decreases significantly with increasing kinetic energy. Once these surfaces are covered with DIP, however, the adsorption probability increases, particularly at the highest incident kinetic energy, and the probability of adsorption exhibits only a weak dependence on the incident kinetic energy. In contrast, on surfaces terminated by octyl- (OTS) and octadecyltrichlorosilane (ODTS) the trapping probability is high and exhibits little dependence on the incident kinetic energy, essentially the same as what is observed on these same surfaces covered by DIP. We postulate, which is backed by the results of molecular dynamics simulations, that direct molecular insertion into the OTS and ODTS layers is a primary explanation for efficient trapping on these surfaces.

Measurements of surface diffusivity and coarsening during pulsed laser deposition.

Pulsed laser deposition (PLD) of homoepitaxial SrTiO(3) 001 was studied with in situ x-ray specular reflectivity and surface diffuse x-ray scattering. Unlike prior reflectivity-based studies, these measurements access both time and length scales of the evolution of the surface morphology during growth. In particular, we show that this technique allows direct measurements of the diffusivity for both inter- and intralayer transport. Our results explicitly limit the possible role of island breakup, demonstrate the key roles played by nucleation and coarsening in PLD, and place an upper bound on the Ehrlich-Schwoebel barrier for downhill interlayer diffusion.

Coverage dependent adsorption dynamics in hyperthermal organic thin film growth.

We have examined the dynamics of adsorption of diindenoperylene (DIP) on SiO(2) and SiO(2) modified with an interfacial organic layer using in situ real time synchrotron x-ray scattering, focusing on the effects of coverage. On both surfaces we observe a substantial increase in the probability of adsorption with increasing coverage, which is most dramatic at the highest incident kinetic energies. On the initially uncovered surfaces, we observe a smooth decrease in the probability of adsorption with increasing incident kinetic energy, indicative of trapping-mediated adsorption. Once both surfaces are covered by DIP, the effects of incident kinetic energy are greatly reduced, and trapping is very efficient over the range of kinetic energies examined. Possible reasons for efficient trapping at high coverage and at high incident kinetic energy include more efficient momentum transfer due to mass matching, and possibly direct molecular insertion. Comparison to results on another small-molecule, pentacene, suggests that this behavior should be common to hyperthermal growth of a variety of other small-molecule thin films.

Revealing the biography of a hidden medieval manuscript using synchrotron and conventional imaging techniques.

Reading the content of hidden texts from ancient manuscripts has become an increasingly important endeavor thanks to the variety of non-destructive analytical tools and image processing routines available for this task. In this study, portable macro X-Ray Fluorescence (MA-XRF-tube), Visible Hyperspectral Imaging (HSI) together with Synchrotron based macro X-Ray Fluorescence (MA-XRF-SR) are combined with signal processing methods to reveal the biography of a degraded manuscript recycled as binding material for a 16th century printed edition of Hesiod's Works and Days. The analytical techniques allow visualizing the hidden text, revealing passages from the Institutes Justinian, a 6th century A.D codification of the Roman Law, with further marginal comments on medieval Canon Law. In addition, the identification of the materials (e.g. pigments, inks) part of the original manuscript together with their sequence of use are revealed: i) the preparation of the parchment using a Ca-based preparation layer, ii) drawing of ruled guide lines, using a Pb-based pen or ink, iii) writing of the main text using a rich Fe-gall ink with modulating color pigments (Hg-, Cu- and Pb- based) and iv) addition of two types of comments to the main text, one of the ink used for the comments being a Fe-gall ink rich in Cu.

Time-resolved x-ray diffraction techniques for bulk polycrystalline materials under dynamic loading.

We have developed two techniques for time-resolved x-ray diffraction from bulk polycrystalline materials during dynamic loading. In the first technique, we synchronize a fast detector with loading of samples at strain rates of ~10(3)-10(4) s(-1) in a compression Kolsky bar (split Hopkinson pressure bar) apparatus to obtain in situ diffraction patterns with exposures as short as 70 ns. This approach employs moderate x-ray energies (10-20 keV) and is well suited to weakly absorbing materials such as magnesium alloys. The second technique is useful for more strongly absorbing materials, and uses high-energy x-rays (86 keV) and a fast shutter synchronized with the Kolsky bar to produce short (~40 µs) pulses timed with the arrival of the strain pulse at the specimen, recording the diffraction pattern on a large-format amorphous silicon detector. For both techniques we present sample data demonstrating the ability of these techniques to characterize elastic strains and polycrystalline texture as a function of time during high-rate deformation.

[Physical activity among children and adolescents in Germany. Results of the German Health Interview and Examination Survey for Children and Adolescents (KiGGS)]. / Körperlich-sportliche Aktivität von Kindern und Jugendlichen in Deutschland. Ergebnisse des Kinder- und Jugendgesundheitssurveys (KiGGS).

Regular physical activity has a positive effect on health and wellbeing at any age. For this reason, sports and exercise enhancing measures are inherent parts of public health in Germany. The German Health Interview and Examination Survey for Children and Adolescents (KiGGS) provides a nationally representative database which allows a comprehensive analysis of physical activity behaviour among young people. This may support the planning and implementation of health intervention measures. Primary results of KiGGS indicate that most children aged 3 to 10 years regularly go in for sports: around three quarters of girls and boys go in for sports at least once a week, and even more than one third three times a week or more. Children without sport engagement come disproportionately often from families with low socioeconomic status, with a migration background or from former East Germany. Also among adolescents sports and exercise activity is very common. Among 11-17 year olds, how ever, the current recommendation to conduct physical and or sports activities on most days of the week is only achieved by every fourth boy and every sixth girl. Especially girls with low socioeconomic status and with a migration background show a lack of physical activity. These results underline the importance of sports- and exercise-promoting measures in childhood and adolescence, designed for specific target groups.

Multiple time scales in diffraction measurements of diffusive surface relaxation.

We grew SrTiO3 on SrTiO3(001) by pulsed laser deposition, using x-ray scattering to monitor the growth in real time. The time-resolved small-angle scattering exhibits a well-defined length scale associated with the spacing between unit-cell high surface features. This length scale imposes a discrete spectrum of Fourier components and rate constants upon the diffusion equation solution, evident in multiple exponential relaxation of the "anti-Bragg" diffracted intensity. An Arrhenius analysis of measured rate constants confirms that they originate from a single activation energy.

[Benefits of sport activity in adulthood. A longitudinal study over 10 years]. / Nutzen von sportlicher Aktivität im Erwachsenenalte. Eine Längsschnittstudie über 10 Jahre.

This article deals with the question of which longitudinal effect physical activity at the adult age can have on physical fitness and on people's subjective as well as objective state of health. Are persons who are regularly and continuously physically active healthier and fitter than people beginning physical activity at a later age, or than those who have never been physically active at all? The results of the presented longitudinal study, run over a time range of 10 years, with subjects at the middle and later adult age, show that on average physical fitness and subjective health decline with in the analysed time range, but positive effects of physical activity do exist. These show up in a decelerated decline. The constant sportsmen benefit most here, but also a late start with physical activity can improve and stabilize physical fitness and health. Anyway, former physical activity is no guarantee for lifelong fitness and health. The group of the dropouts registers large degradations in both variables after quitting physical activity.

[Examination of motor fitness within the scope of The Child and Adolescent Health Survey]. / Untersuchungen zur Motorik im Rahmen des Kinder- und Jugendgesundheitssurveys.

Several studies indicate that physical performance of children and young people is declining. However, actually available data on physical performance and physical activity of children and young people are not representative and hence no countrywide predictions can be made. The examination of motor fitness in association with development and health of children and young people is indispensable for the implementation of appropriate measures of intervention. The module 'Motoric' in the National Health Survey for Children and Adolescents shall remedy the deficiency of information. For the module, 6,000 children and adolescents, age 4-17 years, will be representatively drawn from the total survey sample. Their physical performance and physical activity will be comprehensively assessed. For this purpose, appropriate tests have been developed. In pilot studies, all methods were tested for practicability, objectivity, reliability, and validity. The application of methods was coordinated between the Robert Koch-Institute and the Institute of Sport and Science of Sports, University of Karlsruhe.