Składowe ogólnej sprawności fizycznej 13−16 letnich polskich futbolistów a ich codzienne odżywianie

У статті розглянуто питання взаємозв’язку між розвитком фізичної підготовленості футболістів віком 13−16 років із їх харчуванням. Установлено позитивну кореляцію між споживанням продуктів різного складу (молочних, фруктів, овочів) та розвитком швидкості, спритності й витривалості в юнаків

Linking microbial enzymatic activities and functional diversity of soil around earthworm burrows and casts

The aim of this work was to evaluate the effect of earthworms (Lumbricidae) on the enzymatic activity and microbial functional diversity in the burrow system (burrow wall 0–3 mm, transitional zone 3–7 mm, bulk soil >20 mm from the burrow wall) and cast aggregates of a loess soil under a pear orchard. The dehydrogenase, β-glucosidase, protease, alkaline phosphomonoesterase, and acid phosphomonoesterase enzymes were assessed using standard methods. The functional diversity (catabolic potential) was assessed using the Average Well Color Development and Richness Index following the community level physiological profiling from Biolog Eco Plates. All measurements were done using soil from each compartment immediately after in situ sampling in spring. The enzymatic activites including dehydrogenase, protease, β-glucosidase and alkaline phosphomonoesterase were appreciably greater in the burrow wall or casts than in bulk soil and transitional zone. Conversely, acid phosphomonoesterase had the largest value in the bulk soil. Average Well Color Development in both the transitional zone and the bulk soil (0.98-0.94 A590nm) were more than eight times higher than in the burrow walls and casts. The lowest richness index in the bulk soil (15 utilized substrates) increased by 86-113% in all the other compartments. The PC1 in principal component analysis (PCA) mainly differentiated the burrow walls and the transitional zone. Utilization of all substrate categories was the lowest in the bulk soil. The PC2 differentiated the casts from the other compartments. The enhanced activity of a majority of the enzymes and increased microbial functional diversity in most earthworm-influenced compartments make the soils less vulnerable to degradation and thus increases the stability of ecologically relevant processes in the orchard ecosystem

Cholinesterase activity in blood and pesticide presence in sweat as biomarkers of children's environmental exposure to crop protection chemicals

Introduction. On the contrary to the adult population exposed to pesticides, mostly on occupational basis, rural children are mostly exposed to pesticides deposited in the environment. However, even this constant, distributed in time exposure to low concentrations of pesticides may led to permanent health disorders and limit children’s harmonious development. Objective. The main objective of the study was to evaluate the usefulness of aacetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) activity determination as a marker of children’s environmental exposure to pesticides. An additional aim was to evaluate the usefulness of sweat patches as a novel, non-invasive method of detection of pesticides in sweat as a measure of pesticide exposure. Materials and method. A total of 108 children living in areas of intense pesticide use, and as a control group, 92 children living in an agro-tourist area were enrolled in the study. The AChE and BuChE activity was assayed colorimetricaly in diluted whole blood or plasma, respectively. In addition, selected pesticides were measured by GC/MS analysis in samples of the subject’s sweat absorbed onto a sorbent. Results. The study demonstrated significantly lower AChE and BuChE activity, respectively, in the diluted whole blood and plasma of children exposed to pesticides, compared to the control group (p<0.001 and p=0.003, respectively). The measured mean level of AChE activity was 241.63 ± 26.76 and 348.0±46.95 mU/µmolHb in the exposed and the control group, respectively, whereas the mean activity of BuChE was 424.1±81.1 and 458.6 ± 86.5 mmol/L/min. In addition, pesticide metabolites were detected in 19 (17.6%) sweat samples collected from exposed children. Conclusions. Altogether, the study indicated that cholinesterase activity is a sensitive marker of the children’s environmental exposure to pesticides, whereas sweat patches are useful devices for collecting samples to be analysed for the presence of the pesticides

Role of Metallic Adlayer in Limiting Ge Incorporation into GaN

Atomically thin metal adlayers are used as surfactants in semiconductor crystal growth. The role of the adlayer in the incorporation of dopants in GaN is completely unexplored, probably because n-type doping of GaN with Si is relatively straightforward and can be scaled up with available Si atomic flux in a wide range of dopant concentrations. However, a surprisingly different behavior of the Ge dopant is observed, and the presence of atomically thin gallium or an indium layer dramatically affects Ge incorporation, hindering the fabrication of GaN:Ge structures with abrupt doping profiles. Here, we show an experimental study presenting a striking improvement in sharpness of the Ge doping profile obtained for indium as compared to the gallium surfactant layer during GaN-plasma-assisted molecular beam epitaxy. We show that the atomically thin indium surfactant layer promotes the incorporation of Ge in contrast to the gallium surfactant layer, which promotes segregation of Ge to the surface and Ge crystallite formation. Understanding the role of the surfactant is essential to control GaN doping and to obtain extremely high n-type doped III-nitride layers using Ge, because doping levels &gt;1020 cm&minus;3 are not easily available with Si

Dependence of InGaN Quantum Well Thickness on the Nature of Optical Transitions in LEDs

The design of the active region is one of the most crucial problems to address in light emitting devices (LEDs) based on III-nitride, due to the spatial separation of carriers by the built-in polarization. Here, we studied radiative transitions in InGaN-based LEDs with various quantum well (QW) thicknesses&mdash;2.6, 6.5, 7.8, 12, and 15 nm. In the case of the thinnest QW, we observed a typical effect of screening of the built-in field manifested with a blue shift of the electroluminescence spectrum at high current densities, whereas the LEDs with 6.5 and 7.8 nm QWs exhibited extremely high blue shift at low current densities accompanied by complex spectrum with multiple optical transitions. On the other hand, LEDs with the thickest QWs showed a stable, single-peak emission throughout the whole current density range. In order to obtain insight into the physical mechanisms behind this complex behavior, we performed self-consistent Schrodinger&ndash;Poisson simulations. We show that variation in the emission spectra between the samples is related to changes in the carrier density and differences in the magnitude of screening of the built-in field inside QWs. Moreover, we show that the excited states play a major role in carrier recombination for all QWs, apart from the thinnest one