Computer simulations of the diffusion of Na and Cl ions across POPC lipid bilayer membranes.

We have carried out molecular dynamics simulations using NAMD to study the diffusivity of Na and Cl ions across a POPC lipid bilayer membrane. We show that an imbalance of positively and negatively charged ions on either side of the membrane leads to the diffusion of ions and water molecules. We considered the cases of both weak and very strong charge imbalance across the membrane.

Physical activity and fruit and vegetable intake: correlations between and within adults in a longitudinal multiethnic cohort.

Purpose: To determine if changes in physical activity were associated with changes in fruit and vegetable intake.

Design: Prospective cohort.

Setting: Hawaii.

Are constructs of the transtheoretical model for physical activity measured equivalently between sexes, age groups, and ethnicities?

Background/purpose: Identifying mediators of physical activity change requires measurement instruments that are reliable, valid, and generalizable to multiple populations. Despite continued application of the transtheoretical model (TTM) to the study of physical activity, the structural components of the TTM measurement instruments have been understudied in diverse populations.

Methods: A multiethnic sample (N = 700, M (age) = 47, 63% women, 38% Caucasian) of participants living in Hawaii completed TTM measures.

Effects of a mandibular repositioning appliance on sleep structure, morning behavior and clinical symptomatology in patients with snoring and sleep-disordered breathing.

Background: Mandibular repositioning appliances (MRAs) have become an established treatment for snoring and sleep-disordered breathing - though most studies only focused on the evaluation of respiratory variables.

Methods: This single-blind, placebo-controlled case-series study investigated the effects of an individually adjustable MRA on psychopathology, macro-/microstructure of sleep, periodic leg movements, morning performance, mood/affect and psychophysiology. Fifty patients (37 males) aged 59.

Oct-4 expression in human endometrium.

The transcription factor Oct-4 is crucial for the maintenance of cell pluripotency and is known to be expressed in embryonic stem cells, germ cells and whole embryos at various stages of development. Oct-4 regulates cell fate in a dose-dependent manner and plays a key role in germ-cell tumours. In the past, several stem-cell markers have been detected, and their role in the pathogenesis of diseases has been discussed frequently.

Efficiency of an infiltration basin in removing contaminants from urban stormwater.

The efficiency of a Stormwater Infiltration Basin (SIB) to remove contaminants from urban stormwater was assessed in the current investigation. The SIB, installed in an urban suburb in eastern Sydney (Australia), was monitored over seven rainfall events to assess the removal efficiency of the remedial device for total suspended solids (TSS), nutrients (TP, TKN, N(ox), TN), trace metals (Cd, Cr, Cu, Fe, Mn, Ni, Pb, Zn), organochlorine pesticides and faecal coliforms (FC) from stormwater. The weighted average concentration (WAC) of TSS in the stormwater effluent from the SIB was reduced by an average of 50%, whereas the WAC of Cu, Pb and Zn were also reduced by an average 68%, 93% and 52%, respectively.

Trace metals and organochlorines in sediments near a major ocean outfall on a high energy continental margin (Sydney, Australia).

Sewage effluent from a large ocean outfall south of Sydney, southeastern Australia, is efficiently dispersed on this high energy continental margin. An enrichment of Ag, Cu, Pb and Zn is only detectable in the fine fraction (<62.5 microm) of sediment.

Investigation of the forest-fire model on a small-world network.

It is shown that the forest-fire model of Bak et al. run on a square lattice network with additional long-range interactions in the spirit of a small-world network results in a scale-free system reminiscent of self-organized criticality without recourse to fine tuning. As the number of these long-range interactions is increased, the cluster size distribution exponent is found to decrease in magnitude as the small-world regime is entered, indicating a change in its universality class.

Simulation studies of polymer translocation through a channel.

Monte Carlo simulation studies of the translocation of homopolymers of length N driven through a channel have been performed. We find that the translocation time tau depends on temperature in a nontrivial way. For temperatures below some critical temperature theta(c), tau approximately T-1.

Anthropogenic trace metals in sediment and settling particulate matter on a high-energy continental shelf (Sydney, Australia).

The anthropogenic contribution of trace metals to settling particulate matter (SPM) and surficial sediments was determined on the high-energy continental shelf adjacent to Sydney, Australia. Settling particulate matter and surficial sediment was collected in the vicinity of a major sewage outfall and at five control sites on the middle shelf (80-100 m water depth). Sediment traps were deployed on 10 occasions for up to 2 weeks during the summer and winter of 1995 and SPM was analyzed for Ag, Co, Cr, Cu, Fe, Mn, Ni, Pb and Zn.

Force-extension curves for a single polymer chain under varying solvent conditions.

We show that Langevin dynamics can be used to obtain force-extension curves for a single polymer chain under varying solvent conditions. We find that the chains obey Hooke-type and Pincus regime behavior for Theta and good solvents. However, in poor solvents a coil-strand coexistence is observed in the equilibrium state and this leads to a quite different type of deformation behavior.

Wavelet and receiver operating characteristic analysis of heart rate variability.

Multiresolution wavelet analysis has been used to study the heart rate variability in two classes of patients with different pathological conditions. The scale dependent measure of Thurner et al. was found to be statistically significant in discriminating patients suffering from hypercardiomyopathy from a control set of normal subjects.

Detection of anthropogenic Cu, Pb and Zn in continental shelf sediments off Sydney, Australia--a new approach using normalization with cobalt.

Concentrations of Co, Cu, Pb and Zn were determined in 107 surficial sediment samples from the continental margin adjacent to Sydney, Australia. The spatial distributions of trace metals in the sediments and the mud content are similar and increase with greater distance from the coast. In contrast, normalization of the concentrations of Cu, Pb and Zn in the total sediment with Co enables a coastal anthropogenic source to be identified.

Small-scale spatial and temporal variance in the concentration of heavy metals in aquatic sediments: a review and some new concepts.

Uncertainty associated with data derived by the analyses of heavy metals in aquatic sediment is due to variance produced in the laboratory (precision), plus 'natural', small-scale spatial variance, (or field variance) at the sampling site. Precision is easily determined and is usually reported in contaminant studies, but field variance is poorly understood and seldom documented. It is important to have an understanding of the field variance because if small-scale spatial variance in the concentration of heavy metals is excessive, regional trends may be limited value.

Physical resuspension and vertical mixing of sediments on a high energy continental margin (Sydney, Australia).

Four sediment cores from the continental margin adjacent to Sydney were analyzed for 210Pb, 137Cs, trace metals (Ag, Cd, Co, Cu, Mn, Ni, Pb, Zn), iron, dry bulk density, mud and moisture content. The concentrations of trace metals in the total sediment are low at all sites, although slightly elevated concentrations of Ag, Cu, Pb and Zn are present in the fine fraction of sediment (< 62.5 microns) near a major ocean outfall.

[Epidemiologic aspects of the histologic types of lung cancer].

An epidemiological study was performed in the county of Erfurt including all lung cancer patients of the years 1963, 1968, and 1972 to 1977, together 2,585 males and 358 females. The following results were found: 1. The incidence of lung cancer increased significantly from 1963 to 1977.

[Lung cancer in the DDR with special reference to histological types and cigarette consumption].

By an analysis in detail of incidences of lung cancer of the years 1971 to 1984 and of the data of consumption of cigarettes per head in GDR during the years 1960 to 1984 we discussed the further trends of morbidity and mortality in lung cancer in our country. We pointed out: 1. From 1972 to 1985 the mortality of lung cancer in males dropped from 6,023 per year to 5,213, while that of females increased from 698 to 959.