Flavonoid,tannin and hypericin concentrations in the leaves of St. John’s wort (Hypericum perforatum L.) are affected by UV-B radiation levels

St. John’s wort (Hypericum perforatum L.) herb is used as a herb-tea or as a food supplement because of its antidepressive properties. St. John’s wort, grown under different levels of UV-B radiation, was analysed for its concentrations of flavonoids, tannins and hypericin. A high level of UV-B radiation increased leaf concentrations of flavonoids from 6.31 to 9.00/100 g in dry matter (DM) and of tannins from 26.6 to 31.4/100 g in DM. The concentration of hypericin in leaves exposed to enhanced UV-B radiation (0.08/100 g in DM) was lower than that of leaves exposed to reduced UV-B radiation (0.09/100 g in DM). We conclude that the concentrations of bioactive substances in St. John’s wort herb can be altered by regulating the environment during plant growth.     

Selenium concentration in St. John’s wort (Hypericum perforatum L.) herb after foliar spraying of young plants under different UV-B radiation levels

St. John’s wort (Hypericum perforatum L.) was grown under different levels of UV-B radiation, with selenium (10 mg l⁻¹ Se applied by foliar spraying in the form of sodium selenate) or without foliar Se application. The different levels of UV-B radiation comprised an enhanced level simulating 17% ozone depletion, ambient level, and a reduced level of UV-B radiation. The concentration of Se in unsprayed plants was from 20 ng g⁻¹ to 120 ng g⁻¹. The concentration of Se in the organs of plants foliarly sprayed with Se ranged from 1000 ng g⁻¹ to 12,000 ng g⁻¹, the highest concentration being detected in plants grown under reduced levels of UV-B radiation. Foliar application of Se fertiliser is feasible and effective in St. John’s wort and results in Se-enriched nutritional supplements.     

On the accuracy of CFD modeling of cyclic high heat flux divertor experiment

To investigate the heat removal capability of conceptual divertor cooling fingers, accurate computational fluid dynamics (CFD) analyses are indispensable. Although the cooling performance of the divertor finger has been successfully high-heat-flux tested under real DEMO conditions in a combined helium loop and electron beam facility at the Efremov Institute, Russia, an accompanying numerical simulation of the experiments is of great importance. This might help to better understand the complex thermo-hydraulic conditions with the aim of predicting other different load cases. To accurately reproduce the experimental boundary conditions, the Gaussian-like shape of the absorbed power was taken into account and the heat losses were estimated. Modeling of the structure thermal conductivity was also found to be an important source of modeling uncertainty. In the context of accurate modeling of experimental conditions, the effect of some modeling assumptions was evaluated. Transient simulations of the cyclic heat flux experiment were performed only for the solid part of the cooling finger to avoid excessively long computation times. The helium cooling was taken into account by the heat transfer coefficient (HTC) on the fluid–structure interface, obtained from the steady-state simulations of the full solid–fluid model. The HTC distribution did not vary with time throughout the entire transient simulation. The modeling error associated with such HTC approximation was estimated for the particular cyclic experiment. It is shown that the simulated temperature cycles on the top of experimental mock-up agree well with the measured data.     

Effect of active medium on sclera creep

Irreversible stretching (creep) of the eye sclera, regarded as the cause of high myopia, has been studied experimentally. Both dramatic acceleration and appreciable deceleration of the bovine sclera creep have been observed in the presence of some enzymes. Connective tissue creep caused by static and cyclic mechanical stress (gravitation, blood pressure, etc.) can be associated with many age-specific and pathological changes. The authors believe that detection of appropriate creep inhibitors will make it possible to replace surgery with preventive therapy in ophthalmology and cosmetology.     

Premorbid personality of patients with adolescent seizure-like schizophrenia

The premorbid personality, features of early ontogenesis and childhood crises periods were studied in 226 patients with attack-like forms of schizophrenia, manifesting itself in adolescence with florid psychotic attacks. The authors describe 8 types of the premorbid personality: 1) hyperthymic; 2) sthenic; 3) sensitive; 4) dissociated; 5) passive; schizoid; 6) explosive; 7) model and 8) deficitary personalities. A clinical analysis of the studied cases deomnstrated that the premorbid type of the patient, along with some other factor may be considered as one of the important indices when making a probability prognosis of the development of the disease.     

Evolution of the structure of a mixed Cu<Subscript>60</Subscript>Fe<Subscript>40</Subscript> powder with increasing deformation

The structure of compacted Cu₆₀Fe₄₀ powder in various stages of thermomechanical processing (with a logarithmic strain varied within e = 0?7.4) has been studied by X-ray diffraction. It is established that the atomic order evolution in this system is characterized by a certain critical strain (e = 4.6), at which a specific deformation-induced nanostructure is formed. In this structure, clusters of a bcc α-Fe phase with dimensions on the order of 200 Å are coherently conjugated with a polycrystalline fcc structure of copper, thus representing a new class of materials.     

High-efficiency LEDs based on <Emphasis Type="Italic">n</Emphasis>-GaSb/<Emphasis Type="Italic">p</Emphasis>-GaSb/<Emphasis Type="Italic">n</Emphasis>-GaInAsSb/<Emphasis Type="Italic">P</Emphasis>-AlGaAsSb type-II thyristor heterostructures

A new type of light-emitting diodes (LEDs), a high-efficiency device based on an n-GaSb/p-GaSb/n-GaInAsSb/P-AlGaAsSb thyristor heterostructure, with the maximum emission intensity at wavelength λ = 1.95 μm, has been suggested and its electrical and luminescent characteristics have been studied. It is shown that the effective radiative recombination in the thyristor structure in the n-type GaInAsSb active region is provided by double-sided injection of holes from the neighboring p-type regions. The maximum internal quantum efficiency of 77% was achieved in the structure under study in the pulsed mode. The average optical power was as high as 2.5 mW, and the peak power in the pulsed mode was 71 mW, which exceeded by a factor of 2.9 the power obtained with a standard n-GaSb/n-GaInAsSb/P-AlGaAsSb LED operating in the same spectral range. The approach suggested will make it possible to improve LED parameters in the entire mid-IR spectral range (2–5 μm).     

American Diabetes Association annual meeting, 1997, and the Teczem Consultant Meeting. Diabetic nephropathy

Increasing numbers of genetic diseases involving bone development and models for these diseases have been identified recently. Analysis of these bone diseases have revealed that regulated action of multiple growth factors and subsequent signal transduction are essential for normal bone formation. In this paper, two murine mutant mice viable motheaten and osteopetrosis are analyzed. Mice with the recessive 'viable motheaten' mutation express a severe immunodeficiency syndrome and bone defects. Mutations at the motheaten locus were shown to be the result of aberrant splicing of the gene encoding hematopoietic cell phosphatase (Hcph). Mice homozygous for the osteopetrosis mutation develop congenital osteopetrosis due to a severe deficiency of osteoclasts. It has been recognized that bone trace element composition analysis helps to define bone-related physiological conditions. We have analyzed bone trace element composition in viable motheaten and osteopetrosis mutant animal models in this study. In order to gain insights into the effects of particular genetic defects on bone trace element composition, inductively coupled plasma atomic emissions spectrometry (ICP-AES) analysis was performed. Marked changes in bone trace element levels were found in limb bones of viable motheaten and osteopetrosis mutant mice. An assessment of these trace element spectrum in the two mutant models with respect to each genetic defects are discussed in this paper.