Little is understood about why some youth from low-socioeconomic-status (SES) environments exhibit good health despite adversity. This study tested whether role models and "shift-and-persist" approaches (reframing stressors more benignly while persisting with future optimism) protect low-SES youth from cardiovascular risk. A total of 163 youth, ages 13-16, completed role model interviews and shift-and-persist measures while cholesterol and inflammatory markers, interleukin-6 (IL-6), and C-reactive protein were assessed. Low-SES youth with supportive role models had lower IL-6. Low-SES youth high in shift-and-persist also had lower IL-6. Shift-and-persist partially mediated the interaction of SES and role models on IL-6. Benefits were not found among high-SES youth. Identifying psychological buffers in low-SES youth has implications for health disparities.

Alcohol is a known myocardial depressant. In a dose-dependent fashion, one can show progressive decline in left ventricular systolic function. This observation has been used to implicate alcohol as a major cause of up to 30% of all dilated cardiomyopathies. However, it is not well recognized that there appears to be a biphasic cardiovascular effect based on the chronic dose of alcohol ingested. At low to moderate doses, studies suggest that alcohol has a favorable impact on cardiovascular outcomes. In other words, patients who have one to two glasses of alcohol per day have fewer myocardial infarctions and an improved survival. Large trials, such as the Physician Health Study, indicate that this benefit may be over wide ranges of doses, from one to seven glasses per week. When this is looked at in higher-risk diabetic patients, the benefit of low to moderate doses of alcohol persists. Together, this information suggests that low to moderate doses of alcohol improve cardiovascular risk, and this benefit may exceed the risk of hypertension or heart failure. It is equally important to recognize the serious down side to alcohol ingestion. At chronic high-dose intake of alcohol, there is a direct relationship to elevated blood pressure. Also, prolonged exposure to alcohol increases the likelihood of developing congestive heart failure. Combining the negative cardiovascular effects with potential danger to other organs, such as the liver, underscores the risk for high-dose alcohol. Therefore, there is a biphasic dose response to alcohol. At low to moderate doses, patients experience an overall cardiovascular benefit; it is only when a critical threshold is reached by high-dose alcohol that one observes the toxic effects. Patients on low to moderate ingestion of alcohol should be reassured, but those on high doses should be strongly encouraged to abstain due to potential toxic effects of alcohol.

Flaws in Zr-2.5 Nb alloy pressure tubes of CANDU nuclear reactors are susceptible to a crack initiation and growth mechanism called Delayed Hydride Cracking (DHC), which is a repetitive process that involves hydrogen diffusion, hydride precipitation, growth of the hydrided region and fracture of the hydrided region at the flaw-tip. The presence of small surface irregularities, or secondary flaws, at the bottom of service-induced fretting flaws in pressure tubes requires an integrity assessment in terms of DHC initiation. Experimental data and analytical modeling are required to predict whether DHC initiation can occur from the secondary flaws. In the present work, an experimental program was carried out to examine the impact of small secondary flaws with sharp radii on DHC initiation from simulated fretting flaws. Groups of cantilever beam specimens containing blunt notches with and without secondary flaws were prepared from unirradiated pressure tube materials hydrided to a nominal concentration of 50 wt ppm hydrogen. The specimens were subjected to multiple thermal cycles to form hydrides at the flaw-tip at different applied stress levels, which straddled the threshold value for DHC initiation. The threshold conditions for DHC initiation were established for different simulated fretting and secondary flaws. The experimental results are compared with predictions from the engineering process-zone DHC initiation model.

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