Biodegradation of urea in river waters under controlled laboratory conditions

The biodegradation of urea in river waters has been evaluated under laboratory conditions. Urea will degrade to ammonia at a rate depending on the bacterial state of the river water and on the water temperature. Under normal conditions no breakdown may be expected to occur at temperatures below 8°C for 14 days contact. In river waters with a high suspended solids content, simulating extreme winter river conditions, a maximum breakdown of 3–6 per cent daily of the original urea levels was found for temperatures not exceeding 8°C during the first 7 days contact.     

Fish intake and serum levels of organochlorines among Japanese women

This study evaluates background serum levels of selected organochlorine compounds among Japanese women of reproductive age and investigates whether lifestyle factors, especially dietary factors, may be associated with these levels. A cross-sectional study was performed on 80 Japanese women, aged 26-43 years, who complained of infertility and were confirmed not to have endometriosis. The serum levels of total toxic equivalency (TEQ), 18 polychlorinated dibenzo-p-dioxins (PCDDs)/polychlorinated dibenzofurans (PCDFs), 4 coplanar polychlorinated biphenyls (cPCBs), 36 ortho-substituted polychlorinated biphenyls (PCBs), and 13 chlorinated pesticides or their metabolites were measured and data were collected on the women's age, residence, occupation, body mass index (BMI), smoking and alcohol habit and 6 dietary intakes (fish, meats, rice, vegetables, fruits and dairy products). The serum median level of total TEQ was 25.1 pg TEQ/g lipid, that of PCDDs/PCDFs/cPCBs was 11.5 pmol/g lipid, that of PCBs was 0.46 nmol/g lipid, and that of total pesticides was 1.32 nmol/g lipid. The serum levels of total TEQ, PCDDs/PCDFs/cPCBs, PCBs and pesticides were positively associated with age (P for trend=0.003, 0.01, 0.005 and 0.01, respectively) and frequent fish consumption (P for trend=0.002, 0.003, 0.0003 and 0.006, respectively). Other lifestyle factors were not associated with serum organochlorine levels. The present study suggests that Japanese women who consume fish frequently in their reproductive period tend to accumulate organochlorines in their bodies.     

Microglial Cell Activation Increases Saturated and Decreases Monounsaturated Fatty Acid Content,but Both Lipid Species are Proinflammatory

Neuroinflammation is a component of age-related neurodegenerative diseases and cognitive decline. Saturated (SFA) and monounsaturated (MUFA) fatty acids are bioactive molecules that may play different extrinsic and intrinsic roles in neuroinflammation, serving as exogenous ligands for cellular receptors, or endogenous components of cell structural, energetic and signaling pathways. We determined the fatty acyl profile of BV2 microglial cells before and after acute activation with lipopolysaccharide (LPS). We also investigated the effect of SFA and MUFA pretreatment on the production of an invasive, neurotoxic phenotype in BV2 cells. Acute activation of BV2 microglia resulted in an increase in the relative content of SFA (12:0, 16:0, 18:0, 20:0, 22:0, and 24:0 increased significantly), and a relative decrease in the content of MUFA (16:1n7, 18:1n7, 18:1n9, 20:1n9, 24:1n9 decreased significantly). In agreement, the major stearoyl-CoA desaturase (SCD) isoform in BV2 cells, SCD2, was significantly down-regulated by LPS. We next treated cells with SFA (16:0 or 18:0) or MUFA (16:1n7 or 18:1n9), and found that levels of secreted IL6 were increased, as was secreted MMP9-mediated proteolytic activity. To test the functional significance, we treated SH-SY5Y neuronal cells with conditioned medium from BV2 cells pretreated with fatty acids, and found a small but significant induction of cell death. Our findings suggest differential intrinsic roles for SFA and MUFA in activated microglial cells, but similar extrinsic roles for these fatty acid species in inducing activation. Expansion of SFA is important during microglial cell activation, but either supplemental SFA or MUFA may contribute to chronic low-grade neuroinflammation.     

Trajectories of emotional well-being in mothers of adolescents and adults with autism.

Raising an adolescent or adult child with a developmental disability confers exceptional caregiving challenges on parents. We examined trajectories of 2 indicators of emotional well-being (depressive symptoms and anxiety) in a sample of primarily Caucasian mothers (N = 379; M age = 51.22 years at Time 1) of adolescent and adult children with an autism spectrum disorder (ASD; M age = 21.91 years at Time 1, 73.2% male). We also investigated within-person associations of child context time-varying covariates (autism symptoms, behavior problems, residential status) and maternal context time-varying covariates (social support network size and stressful family events) with the trajectories of emotional well-being. Data were collected on 5 occasions across a 10-year period. Average patterns of stable (depressive symptoms) and improved (anxiety) emotional well-being were evident, and well-being trajectories were sensitive to fluctuations in both child and maternal context variables. On occasions when behavior problems were higher, depressive symptoms and anxiety were higher. On occasions after which the grown child moved out of the family home, anxiety was lower. Anxiety was higher on occasions when social support networks were smaller and when more stressful life events were experienced. These results have implications for midlife and aging families of children with an ASD and those who provide services to these families. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

The validity and incremental validity of knowledge tests, low-fidelity simulations, and high-fidelity simulations for predicting job performance in advanced-level high-stakes selection.

In high-stakes selection among candidates with considerable domain-specific knowledge and experience, investigations of whether high-fidelity simulations (assessment centers; ACs) have incremental validity over low-fidelity simulations (situational judgment tests; SJTs) are lacking. Therefore, this article integrates research on the validity of knowledge tests, low-fidelity simulations, and high-fidelity simulations in advanced-level high-stakes settings. A model and hypotheses of how these 3 predictors work in combination to predict job performance were developed. In a sample of 196 applicants, all 3 predictors were significantly related to job performance. Both the SJT and the AC had incremental validity over the knowledge test. Moreover, the AC had incremental validity over the SJT. Model tests showed that the SJT fully mediated the effects of declarative knowledge on job performance, whereas the AC partially mediated the effects of the SJT. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Predictors of parenting stress among gay adoptive fathers in the United States.

The authors examined correlates of parenting stress among 230 gay adoptive fathers across the United States through an Internet survey. As with previous research on adoptive parents, results showed that fathers with less social support, older children, and children who were adopted at older ages reported more parenting stress. Moreover, gay fathers who had a less positive gay identity also reported more parenting stress. These 4 variables accounted for 33% of the variance in parenting stress; effect sizes were medium to large. Our results suggest the importance of social support and a positive gay identity in facilitating successful parenting outcomes among gay adoptive fathers. (PsycINFO Database Record (c) 2011 APA, all rights reserved)     

Husbands' and wives' alcohol use disorders and marital interactions as longitudinal predictors of marital adjustment.

In this longitudinal study, the relationships among wives' and husbands' lifetime alcoholism status, marital behaviors, and marital adjustment were tested. Participants were 105 couples from the Michigan Longitudinal Study (MLS), an ongoing multimethod investigation of substance use in a community-based sample of alcoholics, nonalcoholics, and their families. At baseline (T1), husbands and wives completed a series of diagnostic measures, and lifetime diagnosis of alcohol use disorder (AUD, as defined in the Diagnostic and Statistical Manual of Mental Disorders, 4th ed.), was assessed. Couples completed a problem-solving marital interaction task 3 years later at T2, which was coded for the ratio of positive to negative behaviors. Couples also completed a measure of marital adjustment at T4 (9 years after T1 and 6 years after T2). Results showed that husbands' lifetime AUD predicted lower levels of their wife's positive marital behaviors 3 years later but was not related to their own or their wife's marital adjustment 9 years from baseline. By contrast, wives' lifetime AUD had direct negative associations with their own and their husband's marital satisfaction 9 years later, and wives' marital behaviors during the problem-solving task predicted their own and their husband's marital satisfaction 6 years later. Findings indicate that marital adjustment in alcoholic couples may be driven more by the wives' than the husbands' AUD and marital behavior. Implications for intervention with alcoholic couples were discussed. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Robust Empirical Predictions of Residual Performance of Damaged Composites with Quantified Uncertainties

Robust predictions with estimated uncertainties were made for the residual strength of impact-damaged composite laminates based on simple non-destructive measurements of the size of the damage from ultrasound C-scans. Experimental data was acquired for two sets of composite coupons, one with a crossply and the other with a quasi-isotropic layup. The laminates were subject to drop-weight impacts, non-destructively evaluated using ultrasound and then loaded to failure in bending. An empirical model of the residual strength of each laminate layup, as a function of the ultrasound measurements, was generated by fitting a Bayesian linear regression model to the normalised measured data. Bayesian linear regression was demonstrated to provide conservative estimates when only minimal data is available. Unlike classical regression, this technique provides a robust treatment of outliers, which avoids underestimation of residual strength. The Leave-One-Out-Cross-Validation (LOOCV) metric was used to assess the performance of models allowing for the quantitative comparison of the predictive power of regression models as well as being consistent in the presence of outliers in the data. The LOOCV metric indicated that predictions of residual strength are up to 25% more accurate when based on damage area than when using measurements of the damage width or length. The proposed approach provides a robust methodology for performing damage assessments in safety critical composite components based on reliable predictions with quantified uncertainties.