Sökresultat

Filtyp

Din sökning på "*" gav 536412 sökträffar

Interactions between gemini surfactants, 12-s-12, and beta-cyclodextrin as investigated by NMR diffusometry and electric conductometry

The interaction between beta-cyclodextrin (CD) and gemini surfactant of the type alkyl-alpha,omega-bis(dodecyldimethyl-ammonium bromide) with different spacer lengths of 2, 8, and 10 carbons has been investigated by means of electric conductivity (EC) and proton self-diffusion NMR at 298 K. The formation of a 2: 1 (CD: gemini) complex in a two-step mechanism is observed with the first association

Energy and Mass Exchange and the Productivity of Main Siberian Ecosystems (from Eddy Covariance Measurements). 1. Heat Balance Structure over the Vegetation Season

Direct measurements of heat balance (latent heat and sensible heat fluxes) by the eddy covariance method, undertaken in 1998-2000 and 2002-2004, are used to obtain information on the daily, seasonal, and annual dynamics of energy and mass exchange between the atmosphere and the typical ecosystems of Siberia (middle taiga pine forest, raised bog, and true four grass steppe with data for typical tun

Polyelectrolytes confined to spherical cavities

The effects of confining a polyelectrolyte solution containing a polyion and its counterions in spherical cavities of different sizes have been investigated by Monte Carlo simulations using a simple model system. Polyions of three different linear charge densities and counterions of three different valences have been examined. Structure, energy, and free energy properties of all systems have been

The long-term course of depressive disorders in the Lundby Study.

Background. The Lundby Study is a longitudinal cohort study on a geographically defined population consisting of 3563 subjects. Information about episodes of different disorders was collected during field investigations in 1947, 1957, 1972 and in 1997. Interviews were carried out about current health and past episodes since the last investigation; for all subjects information was also collected fr

Dietary fibre in food and protection against colorectal cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC): an observational study

Background Dietary fibre is thought to protect against colorectal cancer but this view has been challenged by recent prospective and intervention studies that showed no protective effect. Methods We prospectively examined the association between dietary fibre intake and incidence of colorectal cancer in 519 978 individuals aged 25-70 years taking part in the EPIC study, recruited from ten European

A Novel Approach of Retrofitting a Combined Cycle With Post Combustion CO2 Capture

Most state-of-the-art natural gas-fired combined cycle (NGCC) plants are triple-pressure reheat cycles with efficiencies close to 60%. However, with carbon capture and storage, the efficiency will be penalized by almost 10% units. To limit the energy consumption for a carbon capture NGCC plant, exhaust gas recirculation (EGR) is necessary. Utilizing EGR increases the CO2 content in the gas turbine

Palaeoclimate perturbations before the Sheinwoodian glaciation: A trigger for extinctiond during the 'Ireviken Event'

Telychian to Sheinwoodian conodonts (Pterospathodus eopennatus ssp. n. 1 Zone through the Ozarkodina sagitta rhenana Superzone) were studied in detail for their oxygen isotope composition. The Upper Kockelella ranuliformis and Ozarkodina sagitta rhenana Zones represent the peak interval of the Sheinwoodian positive δ18Oapatite excursion reflecting the coolest conditions with marine sea–water tempe

Common variants in LSP1, 2q35 and 8q24 and breast cancer risk for BRCA1 and BRCA2 mutation carriers

Genome-wide association studies of breast cancer have identified multiple single nucleotide polymorphisms (SNPs) that are associated with increased breast cancer risks in the general population. In a previous study, we demonstrated that the minor alleles at three of these SNPs, in FGFR2, TNRC9 and MAP3K1, also confer increased risks of breast cancer for BRCA1 or BRCA2 mutation carriers. Three addi

Implications of the view of programs as formal systems

The prevailing view of software development as the production of program systems is abandoned in favor of software development as theory building. This suggests that software development properly should be regarded as a deductive activity following the same methodology as is used in all deductive sciences. Programming is merely the description process in the activity of building theories about thi

Imaging Ultrafast Demagnetization Dynamics after a Spatially Localized Optical Excitation

Ultrashort, coherent x-ray pulses of a free-electron laser are used to holographically image the magnetization dynamics within a magnetic domain pattern after creation of a localized excitation via an optical standing wave. We observe a spatially confined reduction of the magnetization within a couple of hundred femtoseconds followed by its slower recovery. Additionally, the experimental results s

Stress-related challenges in pentose fermentation to ethanol by the yeast Saccharomyces cerevisiae.

Conversion of agricultural residues, energy crops and forest residues into bioethanol requires hydrolysis of the biomass and fermentation of the released sugars. During the hydrolysis of the hemicellulose fraction, substantial amounts of pentose sugars, in particular xylose, are released. Fermentation of these pentose sugars to ethanol by engineered Saccharomyces cerevisiae under industrial proces

Genome-based identification and analysis of collagen-related structural motifs in bacterial and viral proteins.

Collagens are extended trimeric proteins composed of the repetitive sequence glycine-X-Y. A (c) under bar ollagen- related (S) under bar tructural (m) under bar otif (CSM) containing glycine-X-Y repeats is also found in numerous proteins often referred to as collagen-like proteins. Little is known about CSMs in bacteria and viruses, but the occurrence of such motifs has recently been demonstrated.

Trophic interactions in changing landscapes: responses of soil food webs

Soil communities in landscapes that are rapidly changing due to a range of anthropogenic processes can be regarded as highly transient systems where interactions between competing species or trophic levels may be seriously disrupted. In disturbed communities dispersal in space and time has a role in ensuring continuity of community function. Stable communities, in undisturbed systems, are more dep

A virtual vibrational self-consistent-field method for efficient calculation of molecular vibrational partition functions and thermal effects on molecular properties.

A new method is described for the calculation of molecular vibrational partition functions and thermal effects on molecular properties including an explicit account of anharmonicity. The approach is based on the vibrational self-consistent-field method. Partition functions and thermal averages of the energies calculated with the new method are generally in good agreement with the result of more ac

A Proline-Rich Region with a Highly Periodic Sequence in Streptococcal beta Protein Adopts the Polyproline II Structure and Is Exposed on the Bacterial Surface.

Proline-rich regions have been identified in many surface proteins of pathogenic streptococci and staphylococci. These regions have been suggested to be located in cell wall-spanning domains and/or to be required for surface expression of the protein. Because little is known about these regions, which are found in extensively studied and biologically important surface proteins, we characterized th

Lifespan and mortality of old oaks - combining empirical and modelling approaches to support their management in Southern Sweden

Old oaks (Quercus robur L.) play an important role in the southern Scandinavian landscape by providing habitat for a wide range of species, a large proportion of them being currently on the National Redlists. To provide support for the management of these trees, we review data on oak mortality and formulate a mortality-driven stochastic model analysing interactions between mortality rate, oak recr

Patch testing with a new fragrance mix detects additional patients sensitive to perfumes and missed by the current fragrance mix

The currently used 8% fragrance mix (FM I) does not identify all patients with a positive history of adverse reactions to fragrances. A new FM II with 6 frequently used chemicals was evaluated in 1701 consecutive patients patch tested in 6 dermatological centres in Europe. FM II was tested in 3 concentrations - 28% FM II contained 5% hydroxyisohexyl 3-cyclohexene carboxaldehyde (Lyral((R))), 2% ci

Relationship between the clinical scoring and demyelination in central nervous system with total antioxidant capacity of plasma during experimental autoimmune encephalomyelitis development in mice

Experimental autoimmune encephalomyelitis (EAE) was induced in a mouse model (C57/BL6) to investigate the antioxidant status of animals at various clinical stages of the disease. For this purpose, blood, brain and spinal cord samples from EAE mice were collected and examined at different scores following post-immunization with myelin oligodendrocyte glycoprotein (MOG). The clinical sign of mobilit

In vivo XRF analysis of mercury: the relation between concentrations in the kidney and the urine

The objective of this study was to determine the concentrations of mercury in organs of occupationally exposed workers using in vivo x-ray fluorescence analysis. Twenty mercury exposed workers and twelve occupationally unexposed referents participated in the study. Their mercury levels in kidney, liver and thyroid were measured using a technique based on excitation with partly plane polarized phot