Bonelike apatite formation on niobium metal treated in aqueous NaOH

The essential condition for a biomaterial to bond to the living bone is the formation of a biologically active bonelike apatite on its surface. In the present work, it has been demonstrated that chemical treatment can be used to create a calcium phosphate (CaP) surface layer, which might provide the alkali treated Nb metal with bone-bonding capability. Soaking Nb samples in 0.5 M NaOH, at 25 degrees C for 24 h produced a nano-porous approximately 40 nm thick amorphous sodium niobate hydrogel layer on their surface. Immersion in a simulated body fluid (SBF) lead to the deposition of an amorphous calcium phosphate layer on the alkali treated Nb. The formation of calcium phosphate is assumed to be a result of the local pH increase caused by the cathodic reaction of oxygen reduction on the finely porous surface of the alkali-treated metal. The local rise in pH increased the ionic activity product of hydroxyapatite and lead to the precipitation of CaP from SBF that was already supersaturated with respect to the apatite. The formation of a similar CaP layer upon implantation of alkali treated Nb into the human body should promote the bonding of the implant to the surrounding bone. This bone bonding capability could make Nb metal an attractive material for hard tissue replacements.     

The impact of continuing care adherence on environmental risks, substance use, and substance-related problems following adolescent residential treatment.

The effectiveness of adolescent treatment to reduce substance use has been demonstrated by a number of different literature reviews, yet longer term outcome studies have suggested that continued alcohol and other drug use is common. Participation in continuing care services and reductions in environmental risk factors (e.g., peer substance use or alcohol or drug use in the home) have both been found to be associated with improved posttreatment substance use. The authors conducted Path analysis to examine the experimental direct effect of the Assertive Continuing Care Protocol (S. H. Godley, M. D. Godley, & M. L. Dennis, 2001) on general continuing care adherence following residential treatment and the protocol's indirect effect (via general continuing care adherence) on social and environmental risk factors, as well as subsequent substance use and substance-related problems. Supporting previous findings, the final model indicates that greater adherence to continuing care is associated with reductions in environmental risk, which in turn is associated with reduced adolescent substance use and substance-related problems 9 months after discharge from residential treatment. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

FACTORS AFFECTING THE SOIL MICROBIAL QUALITY MEASUREMENTS OF BIOMASS QUOTIENT AND RESPIRATION QUOTIENT

The soil microbial biomass quotient (expressed as a percentage of the total soil organic carbon) and the specific rate of carbon-dioxide production by soil microbes (respiration quotient) are often used as indicators of stress on soil microbial populations. A low biomass quotient or a high respiration quotient is considered to be an indication of stress from, for example, toxicity from metals in sewage sludge applied to soils. These metabolic quotients are affected by a wide variety of other factors such as the biodegradability of soil organic-carbon amendments, plant inputs of organic carbon into soils, natural variations in microbial population sizes with depth, and in the rhizosphere of plants. These variations could be sufficiently large to make interpretation of changes in biomass quotient and respiration quotient, as a response to stress, problematical.     

Working Alliance, Treatment Satisfaction, and Patterns of Posttreatment Use Among Adolescent Substance Users.

This longitudinal study examined the relationships among the working alliance, treatment satisfaction, and posttreatment use among adolescents in treatment for substance abuse. Adolescents (N = 600) from the Cannabis Youth Treatment study (M. L. Dennis et al., 2002) completed measures of working alliance and treatment satisfaction as well as substance use and substance-related problems at intake and 3, 6, 9, 12, and 30 months' postintake. When controlling for initial substance use and substance-related problems, working alliance, but not treatment satisfaction, predicted use at 3 and 6 months' postintake. Neither working alliance nor treatment satisfaction were predictive of longitudinal patterns of posttreatment use. Implications for the assessment of working alliance and treatment satisfaction are discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Gender and racial differences in treatment process and outcome among participants in the adolescent community reinforcement approach.

Increasingly, evidence-based treatments are being implemented by community treatment providers, and it is important to understand whether they can be implemented with similar quality and equivalent effectiveness across gender and racial groups. This study examined whether initiation, engagement, dosage, treatment satisfaction, or outcomes for adolescents who received the Adolescent Community Reinforcement Approach (A-CRA) in a large implementation effort were equivalent by gender or racial group. Analyses of data from 2,141 adolescents representing 33 sites across the United States revealed no significant differences for initiation, engagement, or retention by gender or race. Ninety-six percent of the sample reported being satisfied with treatment; however, male adolescents had significantly higher rates of treatment satisfaction than female adolescents, and African American adolescents had significantly higher rates of treatment satisfaction than Caucasian adolescents. A subset of the initial sample (n = 1,819) was used to investigate outcomes. All racial groups had significant increases in days abstinent from alcohol and other drugs and in the percentage in recovery across the measurement period but did not differ from one another at the six-month follow-up. Female adolescents had a higher percentage of days abstinent from alcohol and other drugs and were more likely to be in recovery at the six-month follow-up than male adolescents. Overall, process indicators suggest the intervention was well implemented across gender and racial groups and equally effective across racial groups, with males having equivalent gains in abstinence and recovery compared with females despite males having greater intake severity and differential outcomes at six months. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Driving simulator validation for speed research

The behavioral validation of an advanced driving simulator for its use in evaluating speeding countermeasures was performed for mean speed. Using mature drivers, 24 participants drove an instrumented car and 20 participants drove the simulator in two separate experiments. Participants drove on roads which contained transverse rumble strips at three sites, as well as three equivalent control sites. The three pairs of sites involved deceleration, and were the approaches to stop sign intersections, right curves, and left curves. Numerical correspondence (absolute validity), relative correspondence (or validity), and interactive (or dynamic) relative validity were analyzed, the latter using correlations developed from canonical correlation. Participants reacted to the rumble strips, in relation to their deceleration pattern on the control road, in very similar ways in both the instrumented car and simulator experiments, establishing the relative validities. However, participants generally drove faster in the instrumented car than the simulator, resulting in absolute validity not being established.     

99Tcm-DMSA as a dynamic imaging agent for estimating renal blood flow. A comparison with 99Tcm-DTPA

A technique for estimating fractional renal blood flow (RBF) from the early part of the 99Tcm-diethylenetriaminepentaacetate (DTPA) renogram has been described previously and its reproducibility validated in the pig model. The technique is assumed to be applicable to any recirculating gamma-emitting tracer compound. The aim of this study was to determine whether the same method could be applied to 99Tcm-dimercaptosuccinic acid (DMSA) which has been largely neglected as a dynamic imaging agent. Paired estimates of fractional RBF were obtained in Large White (n = 16) and G?ttingen miniature pigs (n = 6) in three groups: group 1, paired 99Tcm-DTPA studies; group 2, paired 99Tcm-DMSA studies; group 3, alternate 99Tcm-DTPA and 99Tcm-DMSA studies. The results showed good agreement between paired results independent of whether 99Tcm-DTPA or 99Tcm-DMSA was used, supporting the assumption that the technique is applicable to any recirculating gamma-emitting tracer compound. The demonstration that fractional RBF can be reliably estimated from the DMSA renogram means that, if required, it may be combined in a single nuclear medicine procedure with conventional static DMSA renal imaging.     

ArgRewrite V.2: an annotated argumentative revisions corpus

Language Resources and Evaluation - Analyzing how humans revise their writings is an interesting research question, not only from an educational perspective but also in terms of artificial...