Memory effects in polymers. I. Orientational memory in the molten state; its relationship to polymer structure and influence on recrystallization rate and morphology

The influence of polymer structure on the orientational memory in the molten state has been studied by observing the crystallization behavior of the molten polymer through differential scanning calorimetry. It is shown that polymers with strong intermolecular forces (e.g., H-bonding) retain the orientation memory even at temperatures above their equilibrium melting temperatures. The retained orientation memory of the polymer melt is shown to influence its recrystallization rate and the morphology.     

The Affinity of Basic Dyes for Leacril 16 Acrylic Fibre

The dyeing affinity of some thiazole and benzothiazole basic azo dyes for Leacril 16 acrylic fibre was measured using Langmuir isotherms. Results show a close dependence of dye structure on affinity.     

Imaginary refractive-index effects on desert-aerosol extinction versus backscatter relationships at 351 nm: numerical computations and comparison with Raman lidar measurements

A numerical model is used to investigate the dependence at 351 nm of desert-aerosol extinction and backscatter coefficients on particle imaginary refractive index (mi). Three ranges (-0.005 < or = mi < or = -0.001, -0.01 < or = mi < or = -0.001, and -0.02 < or = mi < or = -0.001) are considered, showing that backscatter coefficients are reduced as /mi/ increases, whereas extinction coefficients are weakly dependent on mi. Numerical results are compared with extinction and backscatter coefficients retrieved by elastic Raman lidar measurements performed during Saharan dust storms over the Mediterranean Sea. The comparison indicates that a range of -0.01 to -0.001 can be representative of Saharan dust aerosols and that the nonsphericity of mineral particles must be considered.     

The Future of Mental Health.

Examines the two sets of criteria that generally categorize mental health: those that emphasize internal events and those that deal with external events. The author discusses the future of mental health in light of many of its current trends, including greater acceptance of diversity, and he discusses the potential future role of the mental health professional. The author notes that greater numbers of mental health professionals have gotten involved with different populations, and suggests that the majority of mental health professionals will probably be experts in handling small units of behavior or experience for a limited time. The very process of making predictions changes the future course of events. Let us hope that this intricate process will result in greater satisfaction for greater numbers of people. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Timing modulation of a 40-MHz laser-pulse train for target ranging and identification

We have demonstrated a target ranging and identification technique based on the timing modulation of a mode-locked laser coupled with fast incoherent detection. The range-to-target and the target-depth information have been determined with a resolution of better than 25 cm at single-pulse signal-to-noise ratios below 0.1. Our modeling results suggest that laser average power requirements remain a challenge, with upwards of 100 W likely needed for extension of this technique to ranges over 10 km, but improvements in overall system throughput would allow realization of its potential.     

Quantitation of underivatized free amino acids in mammalian cell culture media using matrix assisted laser desorption ionization time-of-flight mass spectrometry

In this investigation, a quantitative matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOFMS) method was developed for the analysis of underivatized free amino acids in mammalian cell culture media. Calibration curves were developed for 12 amino acids over the linear range of 1-100 microM with coefficients of determination ranging from r2 = 0.9220 to r2 = 0.9973. An aerospray method was utilized for the sample deposition method, and the matrix, alpha-cyano-4-hydroxycinnamic acid, served as the internal standard. This assay was used to analyze bioreactor samples from five time points in the process. Concentrations determined through interpolation of the calibration curves were comparable to those obtained via reversed-phase HPLC based analysis with an average percent difference of 19.71%. Repeatability and intermediate precision studies were also performed, and the relative standard deviations ranged from 0.5943 to 21.41 and 3.157 to 18.97, respectively.     

Developing an initial physical function item bank from existing sources

The objective of this article is to illustrate incremental item banking using health-related quality of life data collected from two samples of patients receiving cancer treatment. The kinds of decisions one faces in establishing an item bank for computerized adaptive testing are also illustrated. Pre-calibration procedures include: identifying common items across databases; creating a new database with data from each pool; reverse-scoring "negative" items; identifying rating scales used in items; identifying pivot points in each rating scale; pivot anchoring items at comparable rating scale categories; and identifying items in each instrument that measure the construct of interest. A series of calibrations were conducted in which a small proportion of new items were added to the common core and misfitting items were identified and deleted until an initial item bank has been developed.     

Single mode waveguide properties of m-NA doped Au/PVA nano-composites: Synthesis, characterization and studies

Meta-nitroaniline (m-NA) doped gold/polyvinyl alcohol (Au/PVA) nano-composites are prepared via in-situ reduction of gold salt by employing hydrazine hydrate (HH). Effect of the NLO (non-linear optical) active m-nitroaniline (m-NA) on the photo-physical properties of nano-particles of gold is studied in the colloidal as well as self-supported film form. The UV-Visible absorption bands between 530 and 555 nm due to surface plasmon resonance in Au nano-particles are observed. The absorption values show a shift in the position due to variation in m-NA with respect to the gold concentration. Additional absorption bands are observed after m-NA doping that influences the original position of gold absorption bands. The solutions and the films are further characterized by photoluminescence (PL), FTIR spectroscopy, XRD, TEM and thermal analysis. The particle size as shown by TEM is found to be less than 10 nm. Spin cast nano-composite films show single mode waveguide properties.