Sökresultat

Filtyp

Din sökning på "*" gav 531412 sökträffar

Photoemission study of LT-GaAs

The electronic structure of GaAs (100) grown by low-temperature molecular beam epitaxy was investigated by means of photoemission spectroscopy. Slight differences are found in the valence band spectra of GaAs layers grown at different As-2/Ga flux ratios. Analysis of As 3d core level spectra does not indicate qualitative differences in respect to high temperature grown GaAs (100) layers. The Ga 3d

Determination of specific surface by the BET method

Abstract in French On peut déterminer la surface spécifique par des mesures d’adsorption des gaz ou des vapeurs d’après la théorie de Brunauer-Emmett-Teller, que l’on examine ici, de même que les techniques expérimentales disponibles: méthodes statiques (volumétriques ou gravimétriques) et dynamiques plus ou moins complexes. En s’aidant d’exemples, on discute l’application de la théorie de B.E.T. The theoretical background of the adsorption isotherm equation of Brunauer, Emmett and Teller is reviewed, together with the experimental techniques available for measuring physical adsorption of gases by solids. Examples are given to show how such measurements are used to determine the specific surface of constructional materials.

Tertiary phosphine abstraction from a platinum(II) coordination complex with SeCN-: Crystal and molecular structures of Se=PTA and [Se=PTA-Me]I center dot CH3OH

Reacting [PtCl(PTA)(3)]Cl (PTA = 1,3,5-triaza-7-phosphatricyclo[3.3.1.1(3,7)]decane) with KSeCN in aqueous or MeOH medium results in the abstraction of the PTA ligands to yield Se = PTA. The reaction also proceeds quantitatively by direct reaction of PTA and KSeCN in water or methanol. The methylated PTA ligand, [PTA-Me]I (1-methyl-1-azonia-3,5-diaza-7-phosphatricyclo[3.3. 1.1(3,7)]decane iodide),

Ärans och hjältarnas tid - eller de bondska töntarnas epok?

This subject of this article is the discrepancy in 20th-century popular culture with regard to views on the Middle Ages. On the one hand, the medieval period has come to represent darkness, stupidity and, in the negative sense of the word, an old-fashioned attitude to life. On the other hand, the Middle Ages is often visualised as a positive antithesis to modernity, an age of heoric values, knight

Optimization of energy-window settings for scatter correction in quantitative In-111 imaging: Comparison of measurements and Monte Carlo simulations

Activity quantification in nuclear medicine imaging is highly desirable, particularly for dosimetry and biodistribution studies of radiopharmaceuticals. Quantitative In-111 imaging is increasingly important with the current interest in therapy using Y-90 radiolabeled antibodies. One of the major problems in quantification is scatter in the images, which leads to degradation of image quality. The a

Tubular secretion of Tamm-Horsfall protein is decreased in type 1 (insulin-dependent) diabetic patients with diabetic nephropathy

Signs of glomerular, proximal and distal tubular dysfunction as well as metabolic control were studied in type 1 diabetes mellitus. To that end, the urinary excretion rates of albumin, sodium, phosphate and Tamm-Horsfall protein as well as HbA1c levels were measured in 20 patients with different degrees of diabetic nephropathy (positive Albustix for several years). Eight diabetic patients with sho

Antifeedant and toxic activity of Adhatoda vasica leaf extract against Spodoptera littoralis (Lep., Noctuidae)

The effect of crude methanolic extracts of Adhatoda vasica leaves on the feeding and performance of Spodoptera littoralis larvae was investigated in the laboratory. Feeding on fresh leaves resulted in 100% mortality of larvae after 26 days of unsubstantial growth. The extract exhibited strong antifeedant and toxic activity against the larvae when applied either on leaf discs or incorporated into a

Broadband UBVRCIC photometry of horizontal-branch and metal-poor candidates from the HK and Hamburg/ESO surveys. I.

We report broadband UBV and/or BVRCIC CCD photometry for a total of 1857 stars in the thick-disk and halo populations of the Galaxy. The majority of our targets were selected as candidate field horizontal-branch or other A-type stars (FHB/ A, N = 576), or candidate low-metallicity stars (N = 1221), from the HK and Hamburg/ESO objective-prism surveys. Similar data for a small number of additional s

The inverse conjunction fallacy

If people believe that some property is true of all members of a class such as sofas, then they should also believe that the same property is true of all members of a conjunctively defined subset of that class such as uncomfortable handmade sofas. A series of experiments demonstrated a failure to observe this constraint, leading to what is termed the inverse conjunction fallacy. Not only did peopl

Evidence for the key role of the adipocyte cGMP-inhibited cAMP phosphodiesterase in the antilipolytic action of insulin

Enhancement of cAMP degradation by increased cGMP-inhibited cAMP phosphodiesterase (cGI-PDE) activity is thought to be an important component of the mechanism whereby insulin counteracts catecholamine-induced lipolysis in adipocytes. In this study the selective cGI-PDE inhibitor OPC3911 was used to evaluate this role of cGI-PDE activation in intact rat adipocytes with special reference to changes

Non-analog beta decay of Rb-74

The magnitude of the Coulomb mixing parameter delta (l)(IM) has been experimentally deduced, for the first time, for the B decay of Rb-74. Th, estimated magnitude is derived from the feeding of the non-analog first excited 0(+) state in Kr-74. The inferred upper Limit of 0.07% is small compared to theoretical predictions. The half-life was measured to be 64.90(9) ms. (C) 2001 Published by Elsevier

Experimental human exposure to N,N-dimethylbenzylamine: generation of a controlled atmosphere and biological monitoring

The aim of the present study was to develop a method for generation of dimethylbenzylamine (DMBA) atmospheres in an exposure chamber and to investigate the possibility of using urinary DMBA metabolites for biological monitoring of exposure to DMBA. A DMBA atmosphere was generated by use of the gas-permeation principle. Six healthy male volunteers were exposed for 8 h to DMBA at air levels of 20, 4

On the Consistency of Line-Drawings, Obtained by Projections of Piecewise Planar Objects

This paper deals with line-drawings, obtained from images of piecewise planar objects after edge detection. Such images are used, e.g., for navigation and recognition. In order to be a possible image of a three dimensional piecewise planar object, it has to obey some projective conditions. Criteria for a line-drawing to be correct is given in this paper, along with methods to find possible interpr

STRENGTH TRAINING AFTER STROKE: EFFECTS ON MUSCLE FUNCTION, GAIT PERFORMANCE AND PERCEIVED PARTICIPATION

Popular Abstract in Swedish Det övergripande syftet med denna avhandling var att hos individer med kvarstående muskelsvaghet efter stroke utvärdera effekterna av progressiv styrketräning (PRT) av knäledens sträck- och böjmuskler på muskelstyrka och muskelspänning, men även att analysera om en förbättrad muskelstyrka påverkar gångförmåga och upplevd delaktighet (individens egen upplevelse av hur maThe overall aim of this thesis was to evaluate the effects of strength training on muscle function, gait performance and perceived participation in subjects with chronic mild to moderate post-stroke hemiparesis. A main impairment after stroke is reduced muscle strength. This post-stroke weakness is a major contributor to mobility limitations, which can prevent the resumption of activities of dail

Dictyostelium discoideum salvages purine deoxyribonucleosides by highly specific bacterial-like deoxyribonucleoside kinases

The salvage of deoxyribonucleosides in the social amoeba Dictyostelium discoideum, which has an extremely A + T-rich genome, was investigated. All native deoxyribonucleosides were phosphorylated by D. discoideum cell extracts and we subcloned three deoxyribonucleoside kinase (dNK) encoding genes. D. discoideum thymidine kinase was similar to the human thymidine kinase 1 and was specific for thymid