Alternative representations of war zone stressors: Relationships to posttraumatic stress disorder in male and female Vietnam veterans.

Four conceptualizations of war zone stressor experiences were defined: traditional combat, atrocities-abusive violence, perceived threat, and malevolent environment. Items from the National Vietnam Veterans Readjustment Study (NVVRS) were reviewed for content, and stressor indexes were created. Using retrospective self-report data from the NVVRS, intercorrelations among stressor scores and between these scores and measures of posttraumatic stress disorder (PTSD) were computed for all veterans and for men and women separately. Structural equation modeling procedures followed. Results indicated that the four stressor indexes were internally consistent, reasonably distinct from one another, and influenced PTSD differentially. Men scored significantly higher than women on all 4 indexes. Whereas the pattern of relationships among the variables was comparable across genders, there was evidence that one path coefficient in the model differed for men and women. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Process modeling with neural networks for pulsed GMAW braze welds

In this work, an improved weld-bead geometry and reduced sheet metal distortion were desired in a weld-brazing process used to finish exterior sheet metal prior to painting. Numerical modeling techniques are widely used to model welding processes, but accurate methods for modeling pulsed-welding processes are lacking. Instead, a continuous empirical model of the welding process was developed using a statistically designed experiment and a neural network for data analysis. Graphical methods were used to simulate the process, and robust parameter design techniques were used to analyze response surfaces produced by the model. Using the response surfaces, possible welding procedures were generated and tested. A new process that resulted in improved joint quality was implemented in production.     

Segregation in Yttrium Aluminum Garnet: I, Experimental Determination

Single crystals of yttrium aluminum garnet (YAG) that were doped with various cations were annealed in air at different temperatures for varying amounts of time. Dopants were chosen to probe the effect of size, charge, and site occupancy on surface segregation. Of the dopants that were chosen for the study (calcium, silicon, neodymium, chromium, and strontium), calcium was the only one that consistently segregated upon annealing in air. Calcium enrichment to the (111) surface was measured using Auger electron spectroscopy, and the segregation enthalpy was determined to be δ H _seg≈−32 ± 10 kJ/mol. Enrichment occurred according to variations in valence, as opposed to variations in size; therefore, it is suggested that surface segregation is electrostatically driven. The results indicate that aliovalent substituents could be used for interface property tailoring, whereas isovalent dopants would not be useful.     

TLC and <Superscript>31</Superscript>P-NMR Analysis of Low Polarity Phospholipids

High-performance TLC and ³¹P-NMR were assessed as methods of observing the presence of numerous low polarity phospholipids: bis-phosphatidic acid (BPA), semi-lyso bis-phosphatidic acid (SLBPA), N-acyl phosphatidylethanolamine (NAPE), N-(1,1-dimethyl-3-oxo-butyl)-phosphatidylethanolamine (diacetone adduct of PE, DOBPE), N-acetyl PE, phosphatidylmethanol (PM), phosphatidylethanol (PEt), phosphatidyl-n-propanol (PP), phosphatidyl-n-butanol (PB). Both techniques are non-discriminative and do not require the prior isolation of individual lipids. It appears that 2D TLC is superior to ³¹P NMR in the analysis of low polarity phospholipids. All phosphatidylalcohols were well separated by 2D TLC. However, some compounds which can present difficulty in separation by 2D-TLC (e.g., SLBPA and NAPE; or DOBPE and N-acetyl PE) were easily distinguished using ³¹P NMR so the methods are complimentary. A disadvantage of 2D TLC is that Rf values can vary with different brands and batches of TLC plates. The chemical shifts of ³¹P NMR were less variable, and so a library of standards may not be necessary for peak identification. Another advantage of ³¹P NMR is the ease of quantification of phospholipids. The applicability of the methods was tested on natural extracts of fish brain and cabbage stem.     

Phthalonitrile‐epoxy blends: Cure behavior and copolymer properties

Binary blends composed of 4,4′‐bis(3,4‐dicyanophenoxy)biphenyl (biphenyl PN) and diglycidyl ether of bisphenol A (epoxy resin) and oligomeric n = 4 phthalonitrile (n = 4 PN) and epoxy resin were prepared. The cure behavior of the blends was studied under dynamic and isothermal curing conditions using differential scanning calorimetry, simultaneous thermogravimetric/differential thermal analysis, infrared spectroscopy, and rheological analysis. The studies revealed that phthalonitrile‐epoxy blends exhibited good processability and that they copolymerized with or without the addition of curing additive. In the absence of curing additive, the blends required higher temperatures and longer cure times. The thermal and dynamic viscoelastic properties of amine‐cured phthalonitrile‐epoxy copolymers were examined and compared with those of the neat epoxy resin. The properties of the epoxy resin improved with increasing biphenyl PN content and with n = 4 PN addition. Specifically, the copolymers exhibited higher glass transition temperatures, increased thermal and thermo‐oxidative stabililty, and enhanced dynamic mechanical properties relative to the commercially available epoxy resin. The results showed that the phthalonitrile‐epoxy blends and copolymers have an attractive combination of processability and high temperature properties. © 2008 Wiley Periodicals, Inc. J Appl Polym Sci, 2008     

Ferroelectric lithography

The fact that domain polarization affects the surface properties suggests a method to direct chemical reactions on ferroelectric substrates. In combination with domain manipulation at small scales, a new lithography process is developed to assemble several classes of nanostructures. Three domain patterning techniques, which employ contact electrodes, SPM and e-beam are introduced, with focus on the physical interactions between electrons and ferroelectrics. The effects of electron beam parameters on polarization reorientation are quantified and it is shown that both positive and negative polarization can be achieved depending on conditions. Potential applications of ferroelectric lithography on fabrication of complex structures are illustrated.     

Acid- and base-catalyzed epoxy-phenol thermosets from catechol,resorcinol and hydroquinone: A structure–property study

In order to better understand the design rules of epoxy–phenol thermosets we will report on the chemistry and (thermo)mechanical properties of cured epoxy–phenol thermoset films. Ortho-, meta- and para-isomers of dihydroxybenzene (DHB) were reacted with the diglycidyl ether of bisphenol A (DGEBA) in the presence of an acid catalyst or triphenylphosphine (PPh₃). The glass transition temperatures (T_g) of the cross-linked films decreases in the order of meta- (T_g = 115°C) > ortho- (T_g = 102°C) > para-DHB (T_g = 96°C) as measured by differential scanning calorimetry. Uniaxial tensile testing of cross-linked films showed excellent stress–strain behavior. The average ultimate strength values ranged from 65 to 82 MPa and the average values of the strain-at-break ranged from 4.8% to 6.9% at 25°C for all cross-linked films. When a PPh₃ was used, the network properties were profoundly different. The base catalyzed thermoset of DGEBA and meta-DHB shows a T_g of 85°C, which is 30°C lower than the T_g of the acid-catalyzed analog. Tensile films appear to be more ductile, as they exhibit a strain-at-break of 20%. The results of this study confirm that simple dihydroxybenzene hardeners can be used to prepare cross-linked films with excellent thermomechanical properties.     

Stochastic independence between two implicit memory tasks.

Two experiments tested the statistical relation between performances on two implicit, priming tests of memory: word-fragment completion and perceptual identification. If performance on implicit priming tests is mediated by a single memory system, then stochastic dependence between them should be found. Contrary to this prediction, stochastic independence was obtained between performances on the two tests in all but one condition. For that condition (Experiment 1) the results suggest that subjects may have knowingly used information derived from the first test to complete the second. When perceived similarity was eliminated by altering contextual cues (Experiment 2), stochastic independence was found in this condition as well. The results are not consistent with current multiple memory system interpretations that assign all implicit, priming tests to one system and explicit tests to another. An alternative interpretation is that the degree of dependence between performances on memory tests is determined by the similarity of the component processes that the tests engage and of the information they use. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Feasibility of a Cognitive Restructuring Intervention for Treatment of Chronic Pain in Persons With Disabilities.

Objective: To determine the feasibility of a cognitive restructuring intervention relative to an education intervention for treatment of pain in persons with chronic pain secondary to disability. Study Design: Quasi-experimental. Participants: 18 adults with chronic pain and disability. Interventions: Cognitive restructuring (n = 13) or education (n = 5) group intervention. Main Outcome Measure: Average pain intensity. Results: Participants in the cognitive group reported greater pre- to posttreatment decreases in pain than those in the education group. Participants rated both interventions positively and expressed enthusiasm for psychosocial interventions for pain. Conclusions: Preliminary findings suggest that decreases in pain can occur as a result of a cognitive restructuring intervention and support the feasibility of conducting intervention trials in persons with disability-related chronic pain. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Theoretical implications of the mnemonic benefits of perceptual interference.

How should interfering with the perception of items during study affect memory for those items? Recent research by J. Nairne (see, PA, Vol 76:7468) and E. Hirshman and N. Mulligan (see record 1991-26469-001) has demonstrated that backward pattern masking during study enhances later memory. This article examines whether traditional explanations of encoding benefits, including rehearsal, visual distinctiveness, and encoding effort, can account for this result. No evidence was found for any of these hypotheses. An explanation that focuses on the compensatory processing of higher level perceptual representations is proposed. This explanation provides a plausible explanation of the results of 7 experiments. The article concludes with a discussion of the implications of the explanation for perceptual priming and other manipulations of perceptual interference. (PsycINFO Database Record (c) 2010 APA, all rights reserved)