Thermoelectric clathrates hold significant promise for high temperature applications with zT values exceeding 1.3. The inorganic clathrates have been shown to be both chemically and thermally stable at high temperatures, and high performance can be obtained from both single crystals and processed powders.
View Article and Find Full Text PDFIn Norway there is an ongoing outbreak in pigs of infections with pandemic influenza A(H1N1)v virus. The first herd was confirmed positive on 10 October 2009. As of 26 October, a total of 23 herds have been diagnosed as positive.
View Article and Find Full Text PDFActa Crystallogr B
December 2009
Details of the complex bonding environment present in the molecular centre of an alkyne-bridged dicobalt complex have been examined using a combination of experimental and theoretical charge-density modelling for two compounds which share a central Co(2)C(2) tetrahedral moiety as their common motif. Topological analysis of the experimental electron density illustrates the problem of separating the Co-C bond-critical points (b.c.
View Article and Find Full Text PDFBoehmite (AlOOH) nanoparticles have been synthesized in subcritical (300 bar, 350 degrees C) and supercritical (300 bar, 400 degrees C) water. The formation and growth of AlOOH nanoparticles were studied in situ by small- and wide-angle X-ray scattering (SAXS and WAXS) using 80 keV synchrotron radiation. The SAXS/WAXS data were measured simultaneously with a time resolution greater than 10 s and revealed the initial nucleation of amorphous particles takes place within 10 s with subsequent crystallization after 30 s.
View Article and Find Full Text PDFBackground: A new A(H1N1) influenza virus was detected in April 2009. The virus is now causing a pandemic of influenza. The article presents an overview of symptoms, complications, vulnerable groups, diagnosis and treatment.
View Article and Find Full Text PDFA general solution: In situ synchrotron X-ray scattering in a high-pressure pulsed injection reactor (see picture) shows that magnetite nucleation and growth are temporally separated. Gram-scale crystalline, pure phase, superparamagnetic magnetite nanoparticles were synthesized without surfactants in supercritical water in less than one hour using a laboratory-scale continuous-flow reactor.
View Article and Find Full Text PDFDepending on the number of interstitial solvent molecules, n, crystals of the linear chain compound Co(3)(dipyridylamide)(4)Cl(2) x nCH(2)Cl(2) adopt either symmetrical or unsymmetrical metal chain structures. We explore here the possible reasons for such behavior using Hirshfeld surface analysis of intermolecular interactions as well as the charge density determined from 100(1) K X-ray diffraction data on the unsymmetrical complex Co(3)(dipyridylamide)(4)Cl(2) x 2.11 CH(2)Cl(2), u-1, and crystal structures of u-1 determined from single crystal synchrotron X-ray diffraction data at 20, 150, and 300 K.
View Article and Find Full Text PDFHand hygiene represents the single most effective way to prevent healthcare-associated infections. The World Health Organization, as part of its First Global Patient Safety Challenge, recommends implementation of multi-faceted strategies to increase compliance with hand hygiene. A questionnaire was sent by the European Centre for Disease Prevention and Control to 30 European countries, regarding the availability and organisation of their national hand hygiene campaigns.
View Article and Find Full Text PDFPreviously, we found increased expression of l-arginine metabolizing enzymes in both kidneys from two-kidney, one-clip (2K1C) hypertensive rats (Helle F, Hultstrom M, Skogstrand T, Palm F, Iversen BM. Am J Physiol Renal Physiol 296: F78-F86, 2009). In the present study, we investigate whether AT(1) receptor activation can induce the changes observed in 2K1C.
View Article and Find Full Text PDFThe experimental electron density distribution in a crystal consisting of the simplest conceivable trinuclear carboxylate-bridged iron-mu3-oxo dianion with two alpha-picolinium cations has been determined using both synchrotron (15 K) and conventional (100 K) X-ray diffraction data. The constituent trinuclear oxo-centered molecule consists of six mu2-bridging formate groups between the iron pairs, while the axial ligand for all iron atoms is another formate group. The compound {[FeO(HCOO)5(HCOO)3]2-.
View Article and Find Full Text PDFExperimental charge density modeling of a magnesium dimer complex and subsequent topological analysis reveals the existence of a chemical bond between the two central Mg atoms. Analysis of the molecular system using the energy density, the source function, and several density profiles along the entire bond path portrays the bond as one between two monovalent Mg atoms containing significant covalent character.
View Article and Find Full Text PDFX-ray vision: Single-crystal XRD experiments (see picture) reveal the excited-state structure of the photomagnetic heterobimetallic title complex. The system shows a decrease in all the iron-ligand bond lengths, suggesting that photoexcitation involves a ligand-to-metal charge transfer or a change in the superexchange coupling between the metal centers.
View Article and Find Full Text PDFNanocrystalline ZrO(2) samples with narrow size distributions and mean particle sizes below 10 nm have been synthesized in a continuous flow reactor in near and supercritical water as well as supercritical isopropyl alcohol using a wide range of temperatures, pressures, concentrations and precursors. The samples were comprehensively characterized by powder X-ray diffraction (PXRD), transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS), and the influence of the synthesis parameters on the particle size, particle size distribution, shape, aggregation and crystallinity was studied. On the basis of the choice of synthesis parameters either monoclinic or tetragonal zirconia phases can be obtained.
View Article and Find Full Text PDFIn 2002, Norway experienced a large outbreak of Pseudomonas aeruginosa infections in hospitals with 231 confirmed cases. This fuelled intense public and professional debates on what were the causes and who were responsible. In epidemiology, other sciences, in philosophy and in law there is a long tradition of discussing the concept of causality.
View Article and Find Full Text PDFTwo-kidney, one-clip (2K1C) is a model of renovascular hypertension where we previously found an exaggerated intracellular calcium (Ca(i)(2+)) response to ANG II in isolated afferent arterioles (AAs) from the clipped kidney (Helle F, Vagnes OB, Iversen BM. Am J Physiol Renal Physiol 291: F140-F147, 2006). To test whether nitric oxide (NO) ameliorates the exaggerated ANG II response in 2K1C, we studied ANG II (10(-7) mol/l)-induced calcium signaling and contractility with or without the NO synthase (NOS) inhibitor N(G)-nitro-l-arginine methyl ester (l-NAME).
View Article and Find Full Text PDFAm J Physiol Regul Integr Comp Physiol
December 2008
The effect of tetradecylthioacetic acid (TTA) on the cyclooxygenase (COX) system was investigated in two-kidney, one-clip (2K1C) hypertensive rats. The systolic blood pressure (BP) was increased 6 wk after clipping to 183 +/- 4 vs.127 +/- 3 mmHg in TTA-treated 2K1C rats.
View Article and Find Full Text PDFEngineering of materials with specific physical properties has recently focused on the effect of nano-sized 'guest domains' in a 'host matrix' that enable tuning of electrical, mechanical, photo-optical or thermal properties. A low thermal conductivity is a prerequisite for obtaining effective thermoelectric materials, and the challenge is to limit the conduction of heat by phonons, without simultaneously reducing the charge transport. This is named the 'phonon glass-electron crystal' concept and may be realized in host-guest systems.
View Article and Find Full Text PDFBackground: It is unknown whether preeclampsia is a risk marker for subsequent end-stage renal disease (ESRD).
Methods: We linked data from the Medical Birth Registry of Norway, which contains data on all births in Norway since 1967, with data from the Norwegian Renal Registry, which contains data on all patients receiving a diagnosis of end-stage renal disease (ESRD) since 1980, to assess the association between preeclampsia in one or more pregnancies and the subsequent development of ESRD. The study population consisted of women who had had a first singleton birth between 1967 and 1991; we included data from up to three pregnancies.
Prediction of the movement of water and solutes in the vadose zone requires information on the distribution of spatial trends and heterogeneities in porous media. The present study describes different lithofacies origination mainly from glaciofluvial deposits. Among different lithofacies, hydrological relationships were investigated.
View Article and Find Full Text PDFPesticides applied to agricultural soils are subject to environmental concerns because leaching to groundwater reservoirs and aquatic habitats may occur. Knowledge of field variation of pesticide-related parameters is required to evaluate the vulnerability of pesticide leaching. The mineralization and sorption of the pesticides glyphosate and metribuzin and the pesticide degradation product triazinamin in a field were measured and compared with the field-scale variation of geochemical and microbiological parameters.
View Article and Find Full Text PDFPesticide mineralization and sorption were determined in 75 soil samples from 15 individually drilled holes through the vadose zone along a 28km long transect of the Danish outwash plain. Mineralization of the phenoxyacetic acid herbicide MCPA was high both in topsoils and in most subsoils, while metribuzine and methyltriazine-amine was always low. Organic matter and soil pH was shown to be responsible for sorption of MCPA and metribuzine in the topsoils.
View Article and Find Full Text PDFObjective: Pseudomonas aeruginosa is an opportunistic pathogen that may cause invasive disease. We describe the epidemiology of invasive P. aeruginosa infection in Norway and identify associated clinical factors.
View Article and Find Full Text PDFBackground/aim: Passive Heymann nephritis (PHN) in rats is a commonly used model of membranous glomerulonephritis in man where the cause of proteinuria is not fully resolved. This study was designed to investigate the role of the glomerular charge barrier in development of PHN proteinuria.
Methods: We studied female Sprague-Dawley rats (n = 33) at days 0, 2, 5 and 14 after induction of PHN by injection of antiserum against renal tubular epithelial antigens (anti-Fx1A).
The charge density (CD) of coordination polymer Co3(C8H4O4)4(C4H12N)2(C5H11NO)3 (1) has been determined from multipole modeling of structure factors obtained from single-crystal synchrotron X-ray diffraction measurements at 16 K. The crystal structure formally contains a negatively charged framework with cations and neutral molecules in the voids. However, the CD suggests that the framework is close to neutral, and therefore qualitative conclusions based on formal charge counting, e.
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