Home and mother: Relations with infant temperament.

Mothers of about 100 toddlers at 12, 18, and 24 months completed the Toddler Temperament Scale. Three other data sets were also available: (a) factors representing lab observations; (b) measures of the mothers who completed the Thurstone Temperament Schedule and ratings made by a social worker of the mother's home; and (c) home measures from Home Observation for Measurement of the Environment and the Family Environment Scale. Direct correlations between the first principal component factor from the Toddler Temperament Scale and the corresponding component from the lab factor were .50, .36, .52, at 12, 18, and 24 months, respectively. Maternal characteristics—emotional stability and social dominance—from the Thurstone Temperament Schedule were related to maternal ratings of the toddler on the Toddler Temperament Scale at all ages (rs?=?.25 to .46). There were only a few low-order correlations from environmental characteristics. A regression analysis, with lab factors entered first, indicated that, after the lab component was extracted, maternal temperament made a modest but significant contribution to maternal reports of toddler temperament. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Atomic-level molecular modeling of the nonionic surfactant Triton X-100: the OPE9 component in vacuum and water

The commercially available nonionic surfactant Triton X-100 is a mixture of polyoxyethylene tert-octylphenyl ethers (OPE_n) with an average of n = 9.5 oxyethylene (OE) units in the molecules, and the population maximum at n = 9. Thus, the OPE_{n = 9} component was chosen to be studied by atomic level molecular modeling, using second-generation force fields. The 1,000 conformers generated via random sampling of torsional angles around single bonds yielded 11 clusters based on geometrical similarity. Representatives of geometrically distinctly different clusters with significant populations were chosen from a narrow energy range around the most probable energy to be analyzed for interaction with water. The effect of water on the conformation of the OE chain was found to be modest, similar to the situation that had been reported earlier for the anionic surfactant Aerosol-OT (AOT). The number of bound water molecules is strongly dependent on the conformation of the OE chain and is affected by electrostatic as well as steric effects. Unlike the case of AOT, for which the length of the hydrophobic tail was found to govern the size of reverse micelles in CCl₄, the size of reverse micelles of OPE_{n = 9} cannot be predicted from the dimensions of the hydrophilic tail.     

Adsorption characteristics of polyacrylamide and sulfonate-containing polyacrylamide copolymers on sodium kaolinite

Polyacrylamide and its copolymer containing 6.8 mole % 2-acrylamido-2-methylpropane sulfonic acid were prepared by an irradiation-initiated precipitation polymerization technique. The polymer was characterized by intrinsic viscosity under conditions similar to those used during adsorption measurements. Hydrolytic degradation of the polyacrylamide was found to be negligible under conditions used. The adsorption substrate, sodium kaolinite, was prepared by extensive ion exchange treatment. Equilibrium adsorption of the polymers on the sodium kaolinite was made as a function of polymer concentration, solution pH, ionic strength, and temperature.     

Reactivity imaging of a passive ferritic FeAlCr steel

A technique named reactivity imaging is introduced. It combines optical imaging of a polycrystalline material with orientation imaging by electron back scattering diffraction (EBSD) for a determination of the crystallographic orientation map and scanning electrochemical microscopy (SECM) for a visualization of the local reactivity. Dissolving metal ions from the substrate are directly detected by the scanning Pt tip of the SECM to measure the amount of locally dissolving material. A ferritic light weight steel (alloy Fe7.5Al7Cr) with a strong anisotropic dissolution behaviour was investigated as an example. This steel shows good passivation behaviour both, in air and through anodisation. In the passive state investigated here, the difference in dissolution rate between various crystallographic orientations is only marginal. Grain boundaries on the other hand showed a higher activity as compared to the grains themselves, which is attributed to the electronic tunnelling in the grain boundaries. The results demonstrate that the rate determining step responsible for the anisotropic dissolution does not result from a deficiency in passivation but from the active dissolution kinetics.     

An inter-laboratory trial of the unified BARGE bioaccessibility method for arsenic, cadmium and lead in soil

The Bioaccessibility Research Group of Europe (BARGE) has carried out an inter-laboratory trial of a proposed harmonised in vitro physiologically based ingestion bioaccessibility procedure for soils, called the Unified BARGE Method (UBM). The UBM includes an initial saliva phase and simulated stomach and intestine compartments. The trial involved the participation of seven laboratories (five European and two North American) providing bioaccessibility data for As (11 samples), Cd (9 samples) and Pb (13 samples) using soils with in vivo relative bioavailability data measured using a swine model. The results of the study were compared with benchmark criteria for assessing the suitability of the UBM to provide data for human health risk assessments. Mine waste and slag soils containing high concentrations of As caused problems of poor repeatability and reproducibility which were alleviated when the samples were run at lower soil to solution ratios. The study showed that the UBM met the benchmark criteria for both the stomach and stomach & intestine phase for As. For Cd, three out of four criteria were met for the stomach phase but only one for the stomach & intestine phase. For Pb two, out of four criteria were met for the stomach phase and none for the stomach & intestine phase. However, the study recommends tighter control of pH in the stomach phase extraction to improve between-laboratory variability, more reproducible in vivo validation data and that a follow up inter-laboratory trial should be carried out.     

Viscosity ratio: A key factor for control of oil drop size distribution in effervescent atomization of oil-in-water emulsions

The present study focused on the effervescent atomization of oil-in-water emulsions and its influence on the internal emulsion structure. The impact of atomization conditions and nozzle geometry on an oil-in-water emulsion with varied viscosity ratio of disperse phase to emulsion was determined. The viscosity ratio is known as a key factor for the drop breakup in emulsification processes. The results depict that oil drops are broken up according to emulsification mechanisms during atomization. A maximum breakup was found for a viscosity ratio between 0.5 and 1. The expected stress dependency of the drop size change was observed for high viscosity ratios only. Relevance of elongational stress on the drop breakup was proven with significant drop size change at high viscosity ratios. The viscosity ratio thus allows for an efficient control of oil drop size change in effervescent atomization as the spray characteristics are invariant to viscosity changes within certain limits.     

Deposition Uniformity and Particle Size Distribution of Ambient Aerosol Collected with a Rotating Drum Impactor

Rotating drum impactors (RDI) are cascade type impactors used for size and time resolved aerosol sampling, mostly followed by spectrometric analysis of the deposited material. They are characterized by one rectangular nozzle per stage and are equipped with an automated stepping mechanism for the impaction wheels. An existing three-stage rotating drum impactor was modified, to obtain new midpoint cutoff diameters at 2.5 μm, 1 μm, and 0.1 μm, respectively. For RDI samples collected under ambient air conditions, information on the size-segregation and the spatial uniformity of the deposited particles are key factors for a reliable spectrometric analysis of the RDI deposits. Two aerodynamic particle sizers (APS) were used for the determination of the RDI size fractionation characteristics, using polydisperse laboratory room air as quasi-stable proxy for urban ambient air. This experimental approach was suitable for the scope of this study, but was subject to numerous boundary conditions that limit a general use. Aerodynamic stage penetration midpoint diameters were estimated to be 2.4 and 1.0 μm for the first two RDI stages. Additionally, the spatial uniformity and geometrical size distribution of the deposited aerosol were investigated using micro-focus synchrotron radiation X-ray fluorescence spectrometry (micro-SR-XRF) and transmission electron microscopy (TEM), respectively. The size distribution of the particles found on the TEM samples agreed well with the results from the APS experiments. The RDI deposits showed sufficient uniformity for subsequent spectrometric analysis, but in the 2.5–10 μm size range the particle area density was very low. All of the applied methods confirmed the theoretical cutoff values of the modified RDI and showed that compared to other cascade impactors, the determined stage penetration sharpness was rather broad for the individual impactor stages.