Sökresultat

The mechanical behavior of individual P pili of uropathogenic Escherichia coli has been investigated using optical tweezers. P pili, whose main part constitutes the PapA rod, composed of 103 PapA subunits in a helical arrangement, are distributed over the bacterial surface and mediate adhesion to host cells. They are particularly important in the pathogenesis of E. coli colonizing the upper urinar

The liquid crystal formed by surfactant AOT/water mixtures in its lamellar mesophase at a spacing between lamellae, d, equal to 8 nm, is mixed with poly(dimethylacrylamide) (PDMAA) polymers of low molecular weight in the range M-n= 2-20 x 10(3); the polymers are synthesized by living radical polymerization. The lowest molecular weights do not affect d significantly, indicating that the polymer coi

A graphic method was developed for presentation of the location and extent of the myocardium at risk in patients with acute myocardial infarction (AMI). This method is based on a mathematical processing of ST-segment deviations of standard 12-lead electrocardiogram following the concept of Titomir and Ruttkay-Nedecky in their dipolar electrocardiotopographic method. The center of the location of t

Using effective infinite dilution ion-ion interaction potentials derived from explicit-water molecular dynamics (MD) computer simulations in the hypernetted-chain (HNC) integral equation theory we calculate the liquid structure and thermodynamic properties, namely, the activity and osmotic coefficients of various multicomponent aqueous electrolyte mixtures. The electrolyte structure expressed by t

Forty-three strains of group B streptococci (GBS) of types Ia, Ib, II and III were tested for susceptibility to chlorhexidine in concentrations ranging from 256 to 0.25 mg/l using the agar and tube dilution methods. The strains showed minimum inhibitory concentration (MIC) values ranging from 0.5 to 1 mg/l. Serum added to the test medium (50%) increased the MIC values to 4-8 mg/l, while amniotic f

Samples were prepared for ultrastructural studies of the intact interface between metallic implants and tissue by transmission electron microscopy. The method is based on plastic embedding of implant and tissue and subsequent removal of the bulk metal by electrochemical dissolution (electropolishing), to facilitate preparation of ultrathin sections for transmission electron microscopy. Surface sen

Intestinal spirochetes in humans have been recognized for more than a century, but it is still a matter of debate whether they are just commensal organisms or whether they cause colorectal disease. Most descriptions to date are of adult patients, while reports in the pediatric literature have been scarce. In a retrospective study we found eight children with intestinal spirochetosis. The findings,

In 1994 and 1995, we investigated the relationship between stream morphology and water chemistry and levels of organochlorines (HCB, PCB, and DDT) in young-of-the-year brown trout (Salmo trutta) from 25 streams in southern Sweden. Contrary to earlier findings for lakes, we found a positive relationship between trophic status (total phosphorus) and uptake of persistent pollutants in stream biota (t

Generalist predators contribute to pest suppression in agroecosystems. Spider communities, which form a substantial fraction of the generalist predator fauna in arable land, are characterized by two functional groups: web-building and cursorial (non-web-building) species. We investigated the relative impact of these two functional groups on a common pest (Sitobion avenae, Aphididae) in wheat by co

Vascular smooth muscle contractile responses to neuropeptide Y, alpha,beta-methyleneATP and noradrenaline were studied in circular segments of isolated vessels with intact endothelium in vitro from 12 patients with diabetes mellitus type 2 (NIDDM) and 12 control subjects. The dilatory effect of acetylcholine was used to test the function of the endothelium. Subcutaneous arteries and veins (diamete

1. In models of size-structured predator-prey systems, the effects are evaluated of gape-size limited predation on prey population growth and density when predators are non-interacting, cannibalistic, interfering, and cannibalistic and interfering. 2. Predation from non-interacting predators markedly reduces prey density, compared with prey densities in the absence of predation. When density-depen

We here use knockin mutagenesis in the mouse to model the spectrum of acquired CEBPA mutations in human acute myeloid leukemia. We find that C-terminal C/EBP alpha mutations increase the proliferation of long-term hematopoietic stem cells (LT-HSCs) in a cell-intrinsic manner and override normal HSC homeostasis, leading to expansion of premalignant HSCs. However, such mutations impair myeloid progr

Possible causes of deaths of Oreochromis niloticus in Lake Chivero were examined in relation to changes in limnological conditions monitored over a 25-month period. The fish deaths coincided with the collapse of an algal bloom that had developed and builtup in the lake for 8 months. Chlorophyll a and dissolved oxygen increased to average concentrations of 42.4 mu g l(-1) and 10.9 mg l(-1) respecti

The increasing demand for detecting and quantifying the negative effects on natural habitats caused by anthropogenic activity has led to the development of impact assessment tools. Here, we propose a monitoring method based on the concept of developmental instability (DI) estimated from fluctuating asymmetry (FA) in bilateral morphological traits in a monoclonal strain. The use of monoclonal popul

Simulated and measured correlation and diversity performance for a couple of two-antenna concepts are presented. The results indicate that the three-dimensional isotropic incident field is a good reference case to evaluate diversity performance in a multi-antenna application.