Temporally massed CS presentations generate more fear extinction than spaced presentations.

Rodent fear conditioning models both excitatory learning and the pathogenesis of human anxiety, whereas extinction of conditional fear is a paradigm of inhibitory learning and the explicit model for behavior therapy. Many studies support a general learning rule for acquisition: Temporally spaced training is more effective than massed training. The authors asked whether this rule applies to extinction of conditional fear in mice. The authors find that both short- and long-term fear extinction are greater with temporally massed presentations of the conditional stimulus (CS). The data also indicate that once CS presentations are sufficiently massed to initiate, or "induce," extinction learning, further CS presentations are more effective when spaced. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Older and younger patients with substance use disorders: Outpatient mental health service use and functioning over a 12-month interval.

This observational study compared a nationwide sample of older patients with substance use disorders (n = 3,598; age > 55) with a demographically and diagnostically matched sample of younger patients on initial functioning, subsequent outpatient mental health service use, and 12-month follow-up outcomes. Older patients were initially functioning as well as or better than younger patients according to substance use, psychiatric, family, and legal criteria. The groups received comparable amounts of outpatient mental health care. At a 12-month follow-up, older patients generally had better substance use and functioning outcomes than did younger patients. The findings suggest that older patients with substance use disorders are keeping pace with demographically and diagnostically comparable younger patients in obtaining specialized outpatient mental health services and that they have positive treatment prognoses. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Interaction between birth complications and early maternal rejection in predisposing individuals to adult violence: specificity to serious, early-onset violence

OBJECTIVE: The authors previously reported that birth complications interact with early maternal rejection in predisposing individuals to violence at age 18 years. This study extended the follow-up period for violent offending from 18 years to 34 years, thus increasing the sample of violent offenders threefold and allowing more detailed analyses on onset and type of violence, the form of maternal rejection, and the effect of maternal mental illness. METHOD: Complications in the births of 4,269 males in Denmark, maternal rejection of these individuals before the age of 1 year, and their histories of criminal offenses at age 34 years were assessed. RESULTS: The biosocial interaction previously observed held for violent but not nonviolent crime, was specific to more serious forms of violence and not threats of violence, held for early-onset but not late-onset violence, and was not accounted for by psychiatric illness in the mothers. Being reared in a public care institution in the first year of life and the mother's attempt to abort the fetus were the key aspects of maternal rejection that interacted with birth complications in predisposing a subject to violence. CONCLUSIONS: These findings 1) indicate that the mechanisms underlying early-onset, serious violence differ from those for less serious, late-onset violence, 2) implicate very early factors in the development of violence, 3) highlight the potential importance of integrating psychosocial with biological factors in understanding and preventing violence, and 4) suggest that interventions to reduce birth complications and maternal rejection may help reduce violence.     

SiC-Whisker-Reinforced Glass-Ceramic Composites: Interfaces and Properties

Different types of SiC whiskers were incorporated into lithium aluminosilicate (LAS) and calcium aluminosilicate (CAS) glass-ceramic matrices. Interfaces in these composites were characterized using Auger spectroscopy, scanning electron microscopy (SEM), and transmission electron microscopy (TEM), and the observations were correlated with measurements of fracture toughness and strength. The chemistry and morphology of the resulting interfaces affected the composite strength and toughness and controlled the mode of crack propagation. Certain types of SiC whiskers were characterized by a carbon-rich near-surface chemistry that became more carbon rich after composite fabrication. In these materials, the flexural strength at 20°C increased by up to 400% and the fracture toughness increased by up to 500%. Crack propagation modes were characterized by crack deflection, whisker–matrix debonding, and crack bridging. In contrast, SiC whiskers with stoichiometric near-surface chemistry generally did not form carbon-rich interfaces during composite fabrication, resulting in composites with low strength and fracture toughness.     

Improved burn scar assessment with use of a new scar-rating scale

The subjective assessment of scar appearance is a widely used method in the evaluation of burn outcomes and the efficacy of treatment methods. The purpose of this study is to design a numeric scar-rating scale with better interrater reliability than has previously been reported. The rating scale assesses scar surface, thickness, border height, and color differences between a scar and the adjacent normal skin. Eight raters were trained with use of a standardized set of photographs that provide examples of the scores to be assigned to each level of severity of each scar characteristic. The raters then rated 10 photographs of different scars, referring to the teaching set of pictures for comparison. The intraclass correlation (interrater reliability) was 0.94, 0.95, 0.90, and 0.85 for scar surface, border height, thickness, and color, respectively. This rating system has proved to be a useful tool for the evaluation of scar surface, thickness, border height, and color.     

Experimental study of the kinetics of transient liquid phase solidification reaction in electroplated gold-tin layers on copper

The kinetics of transient liquid phase (TLP) solidification in Au-Sn layers electroplated on Cu foil was investigated using differential scanning calorimetry (DSC). The solidification reaction takes place between a eutectic liquid of melting point 280 °C, which is shown to form in preference to other compositions, and an excess gold-rich layer. The solidification kinetics and the amount of melt formed were measured as a function of foil aging time. It is shown that the well-documented rapid interdiffusion at low temperatures between gold and tin can account for a decrease in the amount of melt produced during heating with age time. An estimate of the effective diffusivity of tin into gold at 295 °C has been obtained from measured solidification rates. The effect of copper diffusing through the gold film on the solidification kinetics was also investigated.     

Electrospray ionisation mass spectrometry facilitates detection of fibrinogen (Bbeta 14 Arg --> Cys) mutation in a family with thrombosis

We report the first direct detection of a fibrinogen mutation by electrospray ionisation mass spectrometry. The propositus, from a family with a history of thrombosis, came to attention after a pulmonary embolism subsequent to a spontaneous abortion. Prolonged thrombin (41 s) and reptilase times (26 s) together with an impairment of fibrinopeptide B release suggested a mutation at the thrombin cleavage site of the Bbeta chain. Direct mass analysis of purified fibrin chains from a thrombin induced clot showed that 50% of the Bbeta chains remained uncleaved. The measured mass of the mono sialo isoform of this uncleaved chain was 54150 Da, compared to a value of 54198 Da for normal Bbeta chains. This decrease of 48 Da in the intact protein is indicative of either a Bbeta 14 Arg to Cys, or Arg to Leu substitution. Heterozygosity for the Bbeta 14 Arg --> Cys mutation was verified by PCR amplification and DNA sequence analysis.     

Effect of residual stress on ACFM crack measurements in drill collar threaded connections

The drill collar threaded connection of the type used in hydrocarbon exploration is a critical component of the drillstring that is highly susceptible to fatigue damage. In an attempt to reduce costly downhole failures the connections are cold rolled to introduce compressive residual stress, and when in service the connections are routinely inspected. The Alternating Current Field Measurement (ACFM) technique is an increasingly popular method of thread inspection, however, results have indicated that the ACFM defect sizing capability may be compromised when it is used to inspect recently cold rolled connections. If a connection is cold rolled without first being defect free, subsequent inspections may under estimate crack depth with the standard interpretation. Inspection before rolling is therefore necessary.