An electron microscopy investigation of the structure of porous silicon by oxide replication

The morphology of porous silicon is studied by scanning electron microscopy (SEM) by making an oxide replica of the pore structure. Highly branched n-type porous silicon samples were prepared and a replica was formed by oxidation of the pores followed by selective removal of the silicon substrate to expose the oxide pores. Scanning and transmission electron microscopy images confirmed many previously held assumptions about porous silicon formation, including the fractal structure and crystallographic propagation; they also provided a clearer understanding of the details of pore formation. The replica procedure also provides a platform for a more facile and comprehensive analysis of the porous silicon morphology.     

Determination of trace isoflavone phytoestrogens in biological materials by capillary electrochromatography

Capillary electrochromatography using a specialty monolithic matrix was utilized in developing a rapid and highly efficient separation of isoflavones in biological materials. Without a preconcentration technique, it is relatively easy to reach ppm-ppb concentrations of these compounds in soy-based foods and verify them structurally using a photodiode array detector. With on-column preconcentration, we were able to measure low-ppb levels in human serum. Using blood samples from human volunteers, whose diet was supplemented by a soy-based product, the method has been validated for high-throughput screening of isoflavones in clinical studies.     

Micro-attenuated total reflection spectral imaging in archaeology: application to Maya paint and plaster wall decorations

Fourier transform infrared (FT-IR) attenuated total reflection (ATR) imaging has been successfully used to identify individual mineral components of ancient Maya paint. The high spatial resolution of a micro FT-IR-ATR system in combination with a focal plane array detector has allowed individual particles in the paint to be resolved and identified from their spectra. This system has been used in combination with micro-Raman spectroscopy to characterize the paint, which was found to be a mixture of hematite and silicate particles with minor amounts of calcite, carbon, and magnetite particles in a sub-micrometer hematite and calcite matrix. The underlying stucco was also investigated and found to be a combination of calcite with fine carbon particles, making a dark sub-ground for the paint.     

Short-term reliability of a brief hazard perception test

Hazard perception tests (HPTs) have been successfully implemented in some countries as a part of the driver licensing process and, while their validity has been evaluated, their short-term stability is unknown. This study examined the short-term reliability of a brief, dynamic version of the HPT. Fifty-five young adults (M_age = 21 yrs) with at least two years of post-licensing driving experience completed parallel, 21-scene HPTs with a one-month interval separating each test. Minimal practice effects (∼0.1 s) were manifested. Internal consistency (Cronbach's alpha) averaged 0.73 for the two forms. The correlation between the two tests was 0.55 (p < 0.001) and correcting for lack of reliability increased the correlation to 0.72. Thus, a brief form of the HPT demonstrates acceptable short-term reliability in drivers whose hazard perception should be stable, an important feature for implementation and consumer acceptance. One implication of these results is that valid HPT scores should predict future crash risk, a desirable property for user acceptance of such tests. However, short-term stability should be assessed over longer periods and in other driver groups, particularly novices and older adults, in whom inter-individual differences in the development of hazard perception skill may render HPT tests unstable, even over short intervals.     

The many faces of social isolation in childhood.

Eighty-eight Grade 2 children were observed during free play and were assessed by peers and teachers on measures of social withdrawal, popularity, and aggression. The children's perceptions of their social skills were also measured. In Grade 4, 81 children were assessed, 55 of whom had been in the original sample. In addition to the Grade 2 measures, children's reports of loneliness and depression were gathered. In Grade 5, 77 children participated, including 51 from the original sample; all measures taken in this grade were similar to those in Grade 4, with the exclusion of behavioral observations. The data revealed at least two distinct subtypes of social isolation, passive-anxious and active-immature. Passive isolation was stable across the three grades; was consistently and concurrently related to peer rejection, internalizing difficulties, and negative social self-perceptions. Active-immature isolation was infrequent and unstable, and was more often associated with aggression and with externalizing difficulties. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Health promotion for women with physical disabilities: A pilot study.

Objective: To pilot test a health promotion intervention for women with physical disabilities. Design: Pre- and postintervention questionnaires. Participants: Two groups of women with physical disabilities (n=15). Intervention: Seven-session weekly workshop intervention grounded primarily in social-cognitive theory. Setting: Disability and rehabilitation settings. Main Outcome Measures: Indicators of health status. Results: Statistically significant positive changes between pre- and postintervention scores on measures of self-efficacy for dietary behaviors, medical decision making, social interaction, physical functioning, impact of physical limitation on role activities, and vitality. Conclusion: Women with disabilities who participate in this health promotion intervention may exhibit improvements on indicators of health status. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Perceived employment barriers and their relation to workforce-entry intent among people with HIV/AIDS.

As treatments have improved health and quality of life for people with HIV/AIDS, many have contemplated workforce reentry. Workforce reentry rarely occurs among people with illness-related disability. The authors mailed a survey that included workforce-entry-related concerns to 1,991 HIV/AIDS clients. Factor analysis extracted 6 areas of concern (benefits loss, work-related health, job skills, discrimination, personal health care, workplace accommodation). Levels of concern generally increased with HIV acuity level and time since last worked. Work-related health concerns predicted consideration of workforce entry, and work-related health concerns and benefits-loss concerns predicted estimated time to return to work. Findings provide quantitative validation of intuitive categories of workforce-entry concerns among people with HIV/AIDS and suggest that concerns may shift with progress toward workforce entry. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Clients Who Stalk Psychologists: Prevalence, Methods, and Motives.

There is emerging recognition that psychologists are susceptible to various forms of intrusiveness by clients, including stalking. Information regarding the contexts in which stalking emerges and the behaviors to which clinicians are subjected is limited. A random sample of Australian psychologists (N = 1,750) was surveyed to ascertain the prevalence, nature, and occupational impact of stalking by clients. Of the 830 respondents, 19.5% had been stalked for 2 weeks or more. Psychologists typically perceived the stalking to be motivated by resentment (42%) or infatuation (19%). Most practitioners altered their professional practice as a consequence of the harassment and 29% considered leaving the profession. Stalking by clients is a salient professional issue that requires greater attention to better manage conduct that is potentially damaging to both therapists and clients. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Social support, support groups, and the cancer patient.

Surveys the literature on social support and cancer and reports results from an empirical investigation of the factors that led cancer patients to join social support groups. Questionnaire data from 666 21–89 yr old cancer patients show that although most Ss received high levels of social support following cancer, some experienced isolated instances of rejection or did not receive the type of support they wanted from family, friends, and medical caregivers. This appeared to be 1 impetus for joining cancer support groups, although Ss reporting a lack of social support were not generally more likely to join support groups than were other Ss. The Profile of Mood States suggested that attenders were somewhat less likely to be depressed than were nonattenders. In addition, cancer support group attenders were more likely to be White middle-class females, to report having more problems, and to use social support resources of all kinds than were nonattenders. Implications for outreach to cancer patients are discussed, and it is concluded that while support groups may be beneficial for many cancer patients, current programs tend to be used largely by the same segment of the population that uses traditional mental health services. (81 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cardiovascular and neurohumoral responses to behavioral challenge as a function of race and sex.

Cardiovascular and hormonal responses to a structured interview, an electronic video game, a cold pressor test, and exercise on a bicycle ergometer were assessed in 83 normotensive Black and White men and women (aged 25–44 yrs). Black Ss showed significantly greater diastolic blood pressure (DBP) responses than White Ss during the cold pressor test, which were not accounted for by an increase in plasma catecholamines. Exercise produced reliably greater systolic blood pressure (SBP) increases in Black women than in Black men or White women. Men showed significantly greater SBP and DBP changes than women during the video game. The pattern of physiological reactivity elicited by challenge may be related to the Ss' race and sex. (PsycINFO Database Record (c) 2010 APA, all rights reserved)