Laser ablation ICP-MS profiling and semiquantitative determination of trace element concentrations in desert tortoise shells: documenting the uptake of elemental toxicants

The outer keratin layer (scute) of desert tortoise shells consists of incrementally grown laminae in which various bioaccumulated trace elements are sequestered during scute deposition. Laser ablation ICP-MS examination of laminae in scutes of dead tortoises revealed patterns of trace elemental distribution from which the chronology of elemental uptake can be inferred. These patterns may be of pathologic significance in the case of elemental toxicants such as arsenic, which has been linked to both shell and respiratory diseases. Laser ablation transects, performed along the lateral surfaces of sectioned scutes, offered the most successful means of avoiding exogenous contamination that was present on the scute exterior. Semiquantitative determination of elemental concentrations was achieved using sulfur, a keratin matrix element, as an internal standard. The results presented here highlight the potential of laser ablation ICP-MS as a diagnostic tool for investigating toxic element uptake as it pertains to tortoise morbidity and mortality.     

Concentration profiles through thin oxide scales by ion-probe microanalysis

The ion microanalyzer has been used to measure concentration profiles through oxide scales formed on oxide dispersion-containing Ni-20 wt pct Cr alloys after high-temperature oxidation. These protective scales are sufficiently thin, generally less than 1.0 μm, to render examination by more established techniques such as electron-probe microanalysis difficult and often fruitless. The operation of the technique is described and the results obtained are discussed. Although the analyses are not yet quantitative, the profiles obtained indicate that the dispersoid is incorporated throughout the whole thickness of the scales, and allow further insight into the mechanism of oxidation of these alloys.     

The relative risk and timing of divorce in families of children with an autism spectrum disorder.

We compared the occurrence and timing of divorce in 391 parents of children with an autism spectrum disorder (ASD) and a matched representative sample of parents of children without disabilities using a survival analysis. Parents of children with an ASD had a higher rate of divorce than the comparison group (23.5% vs. 13.8%). The rate of divorce remained high throughout the son's or daughter's childhood, adolescence, and early adulthood for parents of children with an ASD, whereas it decreased following the son's or daughter's childhood (after about age 8 years) in the comparison group. Younger maternal age when the child with ASD was born and having the child born later in the birth order were positively predictive of divorce for parents of children with an ASD. Findings have implications for interventions focused on ameliorating ongoing and long-term marital strains for parents of children with an ASD. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

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)     

Protein tyrosine phosphorylation in signalling pathways leading to the activation of gelatinase A: activation of gelatinase A by treatment with the protein tyrosine phosphatase inhibitor sodium orthovanadate

Fibroblasts in monolayer culture secrete gelatinase A (MMP2; 72 kDa type IV collagenase) only in its proenzyme form. Unlike other secreted matrix metalloproteinases, progelatinase A is refractory to activation by serine proteinases. Disparate agents, including monensin, cytochalasin D, and concanavalin A, have been found to mediate the activation of gelatinase A zymogen secreted by fibroblast monolayers. Our finding that monensin-mediated activation can be reversed by the protein tyrosine kinase inhibitor genistein (Li et al., Experimental Cell Research 232 (1997) 332) prompted us to investigate the effect of the specific inhibitor of protein tyrosine phosphatases, sodium orthovanadate, on progelatinase A activation. Treatment of fibroblast monolayers with orthovanadate also results in the secretion of activated gelatinase A. This activation is dose- and time-dependent, requires protein synthesis, and is associated with cell membranes. Vanadate-mediated activation does not occur in the presence of herbimycin A, a protein tyrosine kinase inhibitor. As with progelatinase activation mediated by monensin, concanavalin A, and cytochalasin D, orthovanadate treatment results in increased synthesis of the membrane proteinase MT1-MMP, that can catalyze the activation of progelatinase A. Protein tyrosine kinase inhibitors are able to prevent the increase of MT1-MMP mRNA, as shown by Northern blot and RT-PCR. In addition, orthovanadate potentiates the effects of monensin and concanavalin A. While treatment with monensin or concanavalin A result only in an increase of the putative activator MT1-MMP, orthovanadate also reduces the production of the specific inhibitor TIMP-2. These experiments implicate protein tyrosine phosphorylation in the signal transduction pathways which lead to the activation of progelatinase A.     

High-power 1.5 mu m all-MOVPE buried heterostructure graded index separate confinement multiple quantum well lasers

A maximum total CW output power of 190 mW has been obtained at 1.55 mu m using a buried heterostructure graded index separate confinement multiple quantum well laser grown entirely by metalorganic vapour-phase epitaxy.<>     

Fluorometric determination of pyruvate and alpha-ketoglutarate in cerebrospinal fluid and plasma of infants and children. A simple test that screen for metabolic disorders

Levels of pyruvate and alpha-ketoglutarate in the cerebrospinal fluid (CSF) of 26 children, aged 4 months to 5 1/2 years, with febrile seizures and of 19 children, aged 4 months to 14 years, with the diagnosis of epilepsy were not different from values seen in 119 "normal" children 8 days to 14 years of age. The CSF samples from 24 adults, 24 to 81 years of age, suspected of having a herniated disk were also examined. In the pediatric age group, the data showed a highly significant downward trend of CSF and plasma alpha-ketoglutarate values with age; pyruvate values did not change. A correlation of the values of the two keto acids in the blood and CSF of 42 other children without apparent neurologic disease was also made. Findings in a child with thiamine deficiency suggest that CSF alpha-ketoglutarate may be a more sensitive indicator of deficiency than plasma alpha-ketoglutarate or pyruvate. Measurements of these keto acids in plasma and CSF may be diagnostically useful in a variety of metabolic disorders. Findings in 155 children from birth (20 minutes) to 17 years of age without neurologic disease are submitted as a standard of reference.     

Evaluation of impact fracture toughness of polymeric materials by means of the J‐integral approach

The most commonly accepted method of determining impact fracture toughness of polymeric materials that exhibit small scale yielding and negligible influence of dynamic effects is given by the ISO/DIS 17281 Standard, which states that for brittle behavior, basically a linear relationship exists between the fracture energy, U, and the energy calibration factor, ?. This relationship allows calculation of the critical strain energy release rate, G_IC from the slope of the U vs. BW? plot. This paper describes a simpler alternative methodology capable of evaluating impact fracture toughness using the J_c parameter. The J‐integral is evaluated at the instability load point, by calculating the fracture energy required to produce cleavage behavior of a pre‐cracked specimen. The methodology is limited to single edge notched three‐point‐bending specimens with a crack to depth ratio equal to 0.5. Tests were carried out on an instrumented falling weight impact testing machine on the following materials: PP (polypropylene), HDPE (high‐density polyethylene), MDPE (mid‐density polyethlene) and RT‐PMMA (rubber toughened polymethylmetacrylate). Results are in excellent agreement with the critical values determined by the ISO/DIS 17281 Standard.     

Siblings of adults with mild intellectual deficits or mental illness: Differential life course outcomes.

The present study contrasted the later life sibling relationships, patterns of family formation, and psychological distress and well-being of siblings of adults with disabilities to a nondisabled normative group. The authors identified 268 siblings of adults with mild intellectual deficits (ID) and 83 siblings of adults with mental illness (MI) from the Wisconsin Longitudinal Study (R. M. Hauser & W. H. Sewell, 1985; R. M. Hauser, J. Sheridan, & J. R. Warren, 1998), a prospective longitudinal study that followed participants from age 18 years to age 64 years. Compared with the norm (n = 791), siblings of adults with mild ID had more contact with family members and were more likely to live in the same state as the sibling with the disability but reported less affective closeness. Siblings of adults with MI reported more psychological distress, less psychological well-being, and less adaptive personality characteristics compared with the norm, particularly for siblings of men with MI. There were no differences between groups in the patterns of marriage and childbearing. (PsycINFO Database Record (c) 2010 APA, all rights reserved)