A nonlinear least-squares method for determining cerebrospinal fluid formation and absorption kinetics in pseudotumor cerebri

Data from 14 patients with benign intracranial hypertension (pseudotumor cerebri) have been analyzed using a nonlinear least-squares regression model which was developed and programmed from in-hospital microcomputer use. The method of analysis permits rapid estimation of cerebrospinal fluid (CSF) formation and absorption rates as functions of pressure in individual patients using data from constant-rate infusion manometrics. The analysis predicts that prednisone therapy in pseudotumor cerebri reduces resting CSF pressure by increasing CSF absorption at all intracranial pressures studied, and decreasing CSF formation at high pressures. This result is in accordance with evidence suggesting that impaired CSF absorption plays a major role in the pathogenesis of increased intracranial pressure in pseudotumor cerebri.     

Tear hyperosmolarity in renal dialysis patients asymptomatic for dry eye

Plasma levels of IGF-I, IGFBP-I and IGFBP-3 were measured before and during treatment with tamoxifen up to 19+ months in 34 post-menopausal patients with advanced breast cancer. In 28 patients, pro-IGF-IIE (IGF-IIE) levels were determined and IGFBP-3 was evaluated by immunoblot in 27 patients. Tamoxifen suppressed plasma levels of IGF-I by a mean value of 25.5%-37.7% at different times. This effect was fully developed after 1-2 months of treatment. IGF-IIE was decreased by a mean value of 7.7-23.2% at different time intervals during treatment with tamoxifen, but this effect was significant after long-term treatment (19 months +) only. Plasma IGFBP-I increased by a mean value varying between 48.6% and 190.1%. Tamoxifen had no significant effect on total IGFBP-3 levels. However, patients responding to treatment had a 28% reduction in fragmentation of IGFBP-3, while patients with progressive disease had a 36% increase in fragmentation. The difference between responders and non-responders was highly significant. These findings confirm and extend previous observations regarding the effects of treatment with tamoxifen on IGF-I and IGFBP-I. The finding that patients responding to tamoxifen achieve a reduction in the ratio of fragmented to intact IGFBP-3, while patients progressing on therapy experience an increase in the IGFBP-3 fragmentation ratio, suggest that the tumor burden influences IGFBP-3 protease activity in breast- cancer patients.     

Hoarding-induced lever pressing in golden hamsters (Mesocricetus auratus): Illumination, time of day, and shock as motivating operations.

Assessed the effects of illumination, time of day, and shock on the hoarding-induced lever pressing of 42 male golden hamsters. Results of Exp I show that Ss pouched the pellets instead of eating them when there was illumination. It was also observed that the Ss stopped lever pressing in the absence of chamber illumination. When chamber illumination and time-of-day variables were manipulated systematically, this was especially prominent in Ss tested during their night cycle. In Exp II, it was observed that the presence of mild shock, but not pure tone, could also alleviate the need for food deprivation in maintaining a food-reinforced lever press response. Data are discussed in terms of the potential for using illumination and mild shock as alternative sources of establishing motivation for food-reinforced behaviors. (10 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Autombile bumper standoff and collision repair cost

Measurements were made on thirty-six 1977–1980 cars concerning the relative placement of certain components known to exhibit high collision repair cost. The intention was to help identify car features that increase collision repair cost. The measurements were developed from a concept termed BUMPER STANDOFF, defined as the shortest head-on distance from the bumper (either the inner edge, or the reference barrier placed at the outer edge, perpendicular to the car's longitudinal axis, depending on the component distance being measured) to specific components exhibiting high repair cost or frequency. High correlations in the range of r = 0.47–0.82 (p < 0.05-< 0.01) were found between the front fender standoff distance and headlamp standoff distance vs. claim cost and claim frequency. The first structure likely to be impacted for our overall sample in a simple head-on collision, after the bumper, was the headlamp(s), front fender, hood, or grille, with correlations between 0.48 and 1.00 (p < 0.05-0.00). The front fender was singled out among the subcompacts, while the grille predominated for the compacts and intermediates (r = 1.000, p = 0). Results from these laboratory measurements are essentially in agreement with those results obtained from actual crashes in other studies. That is, they all share very high damage frequency and claim or repair cost rankings for the front fender and headlamp(s). Likewise, measurements relating to the first structure impacted, after the bumper, hold promise as predictors of component damage frequency and claim frequency, in relation to headlamp, front fender, and possibily hood and grille measurements. Bumper standoff measurements are proposed as useful indications of a passenger car's damageability in low speed collisions.     

Polyphosphazenes: Synthesis—properties—applications

Various aspects of polyphosphazene chemistry are reviewed. Stable poly (organophosphazenes) can be prepared from an inorganic precursor, poly(dichlorophosphazene), by careful control of polymerization and substitution reaction conditions. The bulk structure and properties of polyphosphazenes are discussed, and attention is given to those polymers which have promise as useful engineering materials. The successful preparation of stable poly(organophosphazenes) appears to have resulted in a new class of polymers for both specialty and large scale commercial development.     

The Fatality Analysis Reporting System as a tool for investigating racial and ethnic determinants of motor vehicle crash fatalities

The Fatality Analysis Reporting System (FARS) is a Department of Transportation database in the public domain that contains detailed information about fatalities resulting from motor vehicle crashes on public roadways in the United States since 1975. However, data on race and Hispanic ethnicity were not collected by FARS until 1999. Since then, completeness of reported racial and ethnic information has varied from State to State. To assess utility of FARS for investigating race- and ethnicity-specific risk factors associated with motor vehicle crash mortality, we examined yearly national and State-specific reporting rates of race and Hispanic ethnicity for 168,863 motor vehicle crash fatalities from 1999 to 2002. In 1999, national reporting was 85% for race and 78% for Hispanic ethnicity. Over the 4-year study period, a significant linear increase in annual reporting for both race and Hispanic ethnicity was evident at the national level, as reporting by individual States improved over time. In 2002, national reporting rates reached 90% for race and 88% for Hispanic ethnicity. Our findings indicate that FARS has become a valuable resource for population-based studies of motor vehicle crash mortality disparities that exist among racial and ethnic subpopulations in the United States.     

Diffusivity of solutes measured in glass capillaries using Taylor's analysis of dispersion and a commercial CE instrument

We present a strategy for the rapid, efficient, and accurate measurement of the coefficient of diffusion (D) of solutes using a commercial capillary electrophoresis (CE) instrument. This approach utilizes the classic analysis of Taylor of the dispersion of solutes pumped hydrostatically through glass capillaries. To obtain accurate values of D, we modified Taylor's analysis of dispersion to account for the finite time required to reach steady-state flow in the capillary when using a CE instrument. Neglecting this effect results in measured diffusivities of phenylalanine, a model solute, that are in error by as much as 60% when compared with published values. We provide an analysis of this effect and a simple strategy for avoiding these errors. Using this approach, we analyze profiles of concentration fronts and measured values of D for phenylalanine to within 5% of published values. We also analyze profiles of pulses of solute. To determine values of D accurately, measurements of dispersion first need to be made as a function of injection volume to correct for the finite width of the injection plug, before they are corrected for unsteady-state flow. This approach also yields values of D for phenylalanine to within 5% of published values. In contrast to other techniques used for the determination of D, this approach requires no fluorescent labeling and is applicable to solutes of any molecular weight.     

Surface-enhanced Raman scattering from individual au nanoparticles and nanoparticle dimer substrates

Surface-enhanced Raman scattering (SERS) intensities for individual Au nanospheres, nanoshells, and nanosphere and nanoshell dimers coated with nonresonant molecules are measured, where the precise nanoscale geometry of each monomer and dimer is identified through in situ atomic force microscopy. The observed intensities correlate with the integrated quartic local electromagnetic field calculated for each specific nanostructure geometry. In this study, we find that suitably fabricated nanoshells can provide SERS enhancements comparable to nanosphere dimers.