Search results

Filter

Filetype

Your search for "*" yielded 528650 hits

Spreading introgression in the wake of a moving contact zone

An increasing number of studies describe moving hybrid zones. This raises the issue of their actual frequency and emphasizes the need for methods that enable the detection of zone movements without historical records. Asymmetric introgression, usually considered as a signature of geographical shift, might be misleading when applied to mitochondrial or potentially non-neutral markers. We investigat

Invasion under a trade-off between density dependence and maximum growth rate

The invasion of alien species and genotypes is an increasing concern in contemporary ecology. A central question is, what life-history traits enable invasion amidst populations of wild species and conventional cultivars? In order to invade, the initially rare species must perform better than their resident competitors. We conducted a mathematical analysis and simulation of a two-species extension

Estrogen and the selective estrogen receptor modulator (SERM) protection against cell death in estrogen receptor alpha and beta expressing U2OS cells

In the current work, we compared the ability of 17 beta-estradiol (E-2) and the selective estrogen receptor modulators (SERMs), tamoxifen (Tam), raloxifene (Ral) and ospemifene (Osp) to promote the survival of osteoblast-derived cells against etoposide-incluced apoptosis. In order to compare the roles of the two estrogen receptor (ER) isotypes, we created a U2OS human osteosarcoma cell line stably

Further results on the relation between nonlinearity and resiliency of Boolean functions

A good design of a Boolean function used in a stream cipher requires that the function satisfies certain criteria in order to resist different attacks. In this paper we study the tradeoff between two such criteria, the nonlinearity and the resiliency. The results are twofold. Firstly, we establish the maximum nonlinearity for a fixed resiliency in certain cases. Secondly, we present a simple searc

Epitope-specific recognition of type II collagen by rheumatoid arthritis antibodies is shared with recognition by antibodies that are arthritogenic in collagen-induced arthritis in the mouse

Objective. To analyze the fine specificity of IgG autoantibodies in sera from rheumatoid arthritis (RA) patients for type II collagen (CII) epitopes that are arthritogenic in collagen-induced arthritis (CIA), a relevant murine model of RA. Methods. For enzyme-linked immunosorbent assay (ELISA) analysis of conformation-dependent autoantibody binding, recombinant chimeric collagens that harbor the r

Enhanced hexane biodegradation in a two phase partitioning bioreactor: Overcoming pollutant transport limitations

The use of an organic solvent can allow to increase the mass transfer, and thereby biodegradation, of hydrophobic gaseous pollutants. The biodegradation of hexane by a Pseudomonas aeruginosa strain was thus optimized in a two phase partitioning bioreactor (TPPB). Silicone oil was first selected among various organic solvents based on its biocompatibility and resistance to R aeruginosa and its high

Analysis of the flow field in a high-pressure homogenizer

Numerous theories have been developed describing the drop break-up in a high-pressure homogenizer (HPH), but they are generally based on quite rudimentary descriptions of the flow fields. As the flow in a real HPH is very extreme, with gaps of 10–100 μm and velocities of hundreds of m/s, it is practically impossible to measure the velocity fields. In this study, a scale model of an HPH made of acr

Development and Application of a ReaxFF Reactive Force Field for Oxidative Dehydrogenation on Vanadium Oxide Catalysts

We have developed a new ReaxFF reactive force field to describe accurately reactions of hydrocarbons with vanadium oxide catalysts. The ReaxFF force field parameters have been fit to a large quantum mechanics (QM) training set containing over 700 structures and energetics related to bond dissociations, angle and dihedral distortions, and reactions between hydrocarbons and vanadium oxide clusters.

Distribution of MR-detected cartilage defects of the patellofemoral joint in chronic knee pain

Objectives: The aim of the study was to detect cartilage defects and determine the center of these defects in MR imaging of the patellofemoral joint (PFJ) in middle-aged people with chronic knee pain. Design: In the format of a prospective study of early osteoarthritis (OA), this cross-sectional study of the signal knee (the most painful one at inclusion in the study in 1990) in 59 individuals, 30

Visual ecology: Hiding in the dark.

The ability of many animals to camouflage themselves against a background is a well-known daytime phenomenon. Now it has even been found to occur at night, highlighting the reality of nocturnal visual predation

Effects of atmospheric dispersion on the PSF background level

Atmospheric dispersion represents a relatively overlooked problem in connection with the ultimate quality of ELT images corrected by adaptive optics (AO). The aim of this paper is to evaluate the contribution from atmospheric dispersion to the background level of the point-spread function (PSF). Since proper suppression of this level is important for the prospects for direct exo-planet observation

The role of Tyr41 and His155 in the functional properties of superoxide dismutase from the Archaeon Sulfolobus solfataricus

We have examined and compared the effects of mutating Y41 and H155 in the iron superoxide dismutase (SOD) from the archaeon Sulfolobus solfataricus (Ss). These two neighboring residues in the active site are known to have crucial functions in structurally related SODs from different sources. The metal analysis indicates a slightly lower iron content after either Y41F or H155Q replacement, without

Associations between CB-153 and p,p'-DDE and hormone levels in serum in middle-aged and elderly men.

Background: Animal and epidemiologic data indicate that exposure to persistent organochlorine pollutants (POPs) may disrupt the hypothalamus-pituitary-thyroid (HPT) and the hypothalamus-pituitary-gonadal (HPG) axes. We have assessed whether the POP-biomarkers 2,2'4,4',5,5'-hexachlorobiphenyl (CB-153) and 1,1-dichloro-2,2-bis(4-chlorophenyl)-ethene (p,p'-DDE) affect thyrotropin (TSH), thyroid hormo

Galileo observes electromagnetically coupled dust in the Jovian magnetosphere

Measurements of dust coupled to the Jovian magnetosphere have been obtained with the dust detector on board the Galileo spacecraft. We report on data obtained during the first four orbits about Jupiter that had flybys of the Galilean satellites: Ganymede (orbits 1 and 2), Callisto (orbit 3), and Europa (orbit 4). The most prominent features observed are highly time variable dust streams recorded t

Risk factors for cardiovascular malformation - a study based on prospectively collected data

Objectives The aim of this study was to identify risk factors for cardiovascular malformation. Methods In a case-referent study prospectively collected data were obtained from original medical records. The study included 277 woman who had infants with a severe cardiac defect, and for each case two referents (medical records study) were included. Data on parental age, maternal reproductive history,

Free flow acoustophoresis: Microfluidic-based mode of particle and cell separation

A novel method, free flow acoustophoresis (FFA), capable of continuous separation of mixed particle suspensions into multiple outlet fractions is presented. Acoustic forces are utilized to separate particles based on their size and density. The method is shown to be suitable for both biological and nonbiological suspended particles. The microfluidic separation chips were fabricated using conventio