Assessing children's competence: Mothers' and teachers' ratings of competent behavior.

The purposes of this study were to test the replicability of the factor structure of the Health Resources Inventory (HRI; E. L. Gesten [see PA, Vol 57:7209]) for teachers, to describe the factor organization of the HRI when used with parents, and to assess the strength of agreement between parents' and teachers' views of children's competence. Parents' ratings were available for 269 children (ages 4 to 12 years), and teachers' ratings were gathered for a subset of 102. Analysis of teachers' responses confirmed a 5-factor structure of the HRI. The factor structure for mothers closely mirrored that of teachers. The similarity of factor structure argues for the usefulness of the HRI in assessing children's competence at home and school. The relatively modest correlation between mothers' and teachers' ratings suggests possible setting differences in children's behavior and/or variance related to rater source. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Explosion dust particle size measurements

In situ measurements of the sizes and concentrations of dust particles generated by the detonation of high explosives in clay soil near Leesville, La., sandy clay soil near Huntsville, Ala., and sandy soils near Orogrande, N.M. are reported. Measurements were generally made within 1 m of the surface (in one case 10 m) at distances ranging from 10 to approximately 50 m from the detonation point with a combination of Knollenberg lightscattering counters (for particles with equivalent radius in the submicron to 15-microm range) and a Knollenberg optical array probe (for particles of 10-150 microm). Measurements were made for periods of several tens of seconds following detonation. All dust size distributions, irrespective of soil or explosive type, exhibit a bimodal character with mass mean radii of approximately 7 and 70 microm. Peak aerosol mass loadings inferred from the distributions have values ranging from 0.05 to 10 g gm-3 with the larger mode of particles contributing most to the mass loading. Predictions of dust extinction coefficients at visible (0.55-microm) and IR (10.4-microm) wavelengths were made using the measured size distributions together with estimates of dust refractive indices. These predictions suggest that extinction should be nearly neutral (wavelength independent) in agreement with transmission measurements made during some of the tests. Predicted mass extinction coefficients, under the assumption of dust material density of 2.5 g cm-3, are of the order of 0.05 m2 g-1 at both visible and IR wavelengths. This value is also in good agreement with a test-averaged measured value of 0.03 m3 g-1 (at lambda = 10.6 microm) obtained using a short path transmissometer and hi-vol sampler.     

Response of Knollenberg light-scattering counters to non-spherical doublet polystyrene latex aerosols

Doublet particles of polystyrene, polyvinyltoluene and styrene vinyltoluene latex were measured with the Knollenberg CSASP and ASASP light-scattering aerosol counters. These instruments respond to these non-spherical particles as they do spheres of equal volume and refractive index, providing particles have equivalent radii r 0.4 μm. However, their response to larger nonspherical particles having equivalent radii in the range 0.4 μm r 1.7 μm cannot be approximated by that for spheres of equal volume or equal cross-section. For even larger particles with equivalent radii 1.7 μm r 4 μm the CSASP response is about the same as for spheres of equal cross-section and refractive index. The counting efficiency of the CSASP and ASASP instruments was checked by measurement of monodisperse aerosol particles of known concentration. These instruments measure aerosol concentrations correctly to within a factor 2 for near-micrometer sized particles.     

Ontogeny and Environment as Determinants of the Secondary Chemistry of Three Species of White Birch

This study investigates variation in the secondary chemistry of the bark of three closely related, winter-dormant species of white birch (Betula resinifera, B. pendula, and B. platyphylla) at different ontogenetic stages by using different plant parts (top and base). The experimental birches were grown for 4 years in two growing conditions (pot and field) at different nutrient levels. There was considerable species-specific quantitative and qualitative variation in the secondary chemicals in bark, but this was also affected by fertilization and the age of the plant. In general, there was greater chemical diversity in saplings than in seedlings. The study revealed three new components, secoisolariciresinol 9-O-β-glucopyranoside and two of its derivatives, that have not been reported previously for the bark of white birches. Principal component analysis showed that the species studied had a similar chemical composition at the juvenile stage, but as the plants grew, they became more clearly differentiated, which indicates that the species of older plants can be identified by chemotaxonomy. Evidently, the secondary chemistry of birches is under genetic control, but it is affected by properties of growing conditions and ontogeny. Electronic Supplementary Material Supplementary material to this paper is available in electronic form at     

Fluorescence-Based Nanoparticle Tracking Analysis and Flow Cytometry for Characterization of Endothelial Extracellular Vesicle Release

As extracellular vesicles (EVs) have become a prominent topic in life sciences, a growing number of studies are published on a regular basis addressing their biological relevance and possible applications. Nevertheless, the fundamental question of the true vesicular nature as well as possible influences on the EV secretion behavior have often been not adequately addressed. Furthermore, research regarding endothelial cell-derived EVs (EndoEVs) often focused on the large vesicular fractions comprising of microvesicles (MV) and apoptotic bodies. In this study we aimed to further extend the current knowledge of the influence of pre-isolation conditions, such as cell density and conditioning time, on EndoEV release from human umbilical vein endothelial cells (HUVECs). We combined fluorescence nanoparticle tracking analysis (NTA) and the established fluorescence-triggered flow cytometry (FT-FC) protocol to allow vesicle-specific detection and characterization of size and surface markers. We found significant effects of cell density and conditioning time on both abundance and size distribution of EndoEVs. Additionally, we present detailed information regarding the surface marker display on EVs from different fractions and size ranges. Our data provide crucial relevance for future projects aiming to elucidate EV secretion behavior of endothelial cells. Moreover, we show that the influence of different conditioning parameters on the nature of EndoEVs has to be considered.     

Single-Particle Fluorescence Spectrometer for Ambient Aerosols

A fluorescence particle spectrometer (FPS) for real-time measurement of the fluorescence spectra of aerosol particles in the size range 1-10 w m diameter is reported. The prototype FPS has a sufficiently high sample rate (from 5 to 28 l/min for 3.5 w m to 11 w m diameter particles) to measure aerosol within buildings at practical rates (from 1 up to 600 particle fluorescence spectra per minute). Previously reported bioaerosol prototype detectors for measurement of single particle spectra (Pan et al., Opt. Lett ., 24, 116-118 (1999); Hill et al., Field Anal. Chem. Tech ., 3, 221-239 (1999)) were unable to sample the ambient environment; air containing particles had to be forced under pressure into a sample cell. In addition, sample rates were so small (less than 0.01 l/min) as to be impractical for most applications. The present design overcomes these deficiencies by the use of an airtight cell that highly concentrates micrometer-sized particles. A virtual impactor first concentrates aerosol particles, which are then drawn under negative pressure through an aerodynamic focusing nozzle in the inlet of the instrument, through the sample region, providing further concentration. The rate of particle spectra measured by the FPS increases significantly when the particle inlet is within a few meters of some common sources of indoor biological particles, e.g., a person coughing, sneezing, or rubbing his skin, or the presence of a dog. The spectra obtained have a variety of spectral shapes. The FPS may be useful in a variety of areas, e.g., in studying and monitoring airborne particles that cause diseases or allergies.     

Optimism and Pessimism as Predictors of Change in Health After Death or Onset of Severe Illness in Family.

The authors prospectively examined changes in health after a major life event (death or onset of severe illness in family) among 5,007 employees (mean age=44.8 years) whose optimism and pessimism levels were assessed in 1997 and major life events in 2000. Health was indicated by sickness absence days during a period covering 36 months prior to the event and 18 months after the event. Increase in sick days after the event was smaller and returned to the preevent level more quickly among highly optimistic individuals than among their counterparts with low optimism. Parallel changes were not observed in relation to pessimism. These findings suggest that optimism may reduce the risk of health problems and may be related to a faster recovery after a major life event. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A europium chelate for quantitative point-of-care immunoassays using direct surface measurement

New labels and assay techniques are needed to improve the sensitivity and quantitativeness of point-of-care immunotesting while sustaining the rapidity and ease of use of the assays. We synthesized a novel, intrinsically fluorescent nonadentate europium chelate with two chromophores and hydrophilic alpha-galactose side groups. The chelate is highly fluorescent, soluble in water, and provides effective shielding of Eu from water. The performance of the nonadentate chelate was compared with a heptadentate chelate in a dry reagent immunoassay for human chorionic gonadotropin (hCG). After 15-min incubation and washing, time-resolved fluorescence was measured directly from a wet or dried well surface. Contrary to the heptadentate label, the effect of aqueous quenching on the nonadentate label was found to be insignificant, with calculated analytical detection limits (background + 3 SD) of 0.9 and 0.7 IU/L hCG for wet and dry measurements, respectively, and a linear range up to 5000 IU/L. The CVs for the new label were <8% at the cutoff of 25 IU/L and above in both whole blood and plasma. The novel nonadentate label facilitates short turnaround times and simple instrumentation due to the absence of all signal development steps, at the same time retaining an excellent immunoassay performance.     

Estimation of nonstationary EEG with Kalman smoother approach: an application to event-related synchronization (ERS)

An adaptive spectrum estimation method for nonstationary electroencephalogram by means of time-varying autoregressive moving average modeling is presented. The time-varying parameter estimation problem is solved by Kalman filtering along with a fixed-interval smoothing procedure. Kalman filter is an optimal filter in the mean square sense and it is a generalization of other adaptive filters such as recursive least squares or least mean square. Furthermore, by using the smoother the unavoidable tracking lag of adaptive filters can be avoided. Due to the properties of Kalman filter and benefits of the smoothing the time-frequency resolution of the presented Kalman smoother spectra is extremely high. The presented approach is applied to estimation of event-related synchronization/desynchronization (ERS/ERD) dynamics of occipital alpha rhythm measured from three healthy subjects. With the Kalman smoother approach detailed spectral information can be extracted from single ERS/ERD samples.