High temperature micropillar compression of Al/SiC nanolaminates

The effect of the temperature on the compressive stress–strain behavior of Al/SiC nanoscale multilayers was studied by means of micropillar compression tests at 23 °C and 100 °C. The multilayers (composed of alternating layers of 60 nm in thickness of nanocrystalline Al and amorphous SiC) showed a very large hardening rate at 23 °C, which led to a flow stress of 3.1 ± 0.2 GPa at 8% strain. However, the flow stress (and the hardening rate) was reduced by 50% at 100 °C. Plastic deformation of the Al layers was the dominant deformation mechanism at both temperatures, but the Al layers were extruded out of the micropillar at 100 °C, while Al plastic flow was constrained by the SiC elastic layers at 23 °C. Finite element simulations of the micropillar compression test indicated the role played by different factors (flow stress of Al, interface strength and friction coefficient) on the mechanical behavior and were able to rationalize the differences in the stress–strain curves between 23 °C and 100 °C

High temperature nanoindentation behavior of Al/SiC multilayers

Nanoscale Al/SiC composite laminates have unique properties, such as high strength, high toughness, and damage tolerance. In this article, the high-temperature nanoindentation response of Al/SiC nanolaminates is explored from room temperature up to 300_C. Selected nanoindentations were analyzed postmortem using focused ion beam and transmission electron microscopy to ascertain the microstructural changes and the deformation mechanisms operating at high temperature

Mechanical Characterization of Lead-Free Sn-Ag-Cu Solder Joints by High-Temperature Nanoindentation

The reliability of Pb-free solder joints is controlled by their microstructural constituents. Therefore, knowledge of the solder microconstituents’ mechanical properties as a function of temperature is required. Sn-Ag-Cu lead-free solder alloy contains three phases: a Sn-rich phase, and the intermetallic compounds (IMCs) Cu6Sn5 and Ag3Sn. Typically, the Sn-rich phase is surrounded by a eutectic mixture of β-Sn, Cu6Sn5, and Ag3Sn. In this paper, we report on the Young’s modulus and hardness of the Cu6Sn5 and Cu3Sn IMCs, the β-Sn phase, and the eutectic compound, as measured by nanoindentation at elevated temperatures. For both the β-Sn phase and the eutectic compound, the hardness and Young’s modulus exhibited strong temperature dependence. In the case of the intermetallics, this temperature dependence is observed for Cu6Sn5, but the mechanical properties of Cu3Sn are more stable up to 200°C

Radiation effects in the environment

Although the Navajo possess substantial resource wealth-coal, gas, uranium, water-this potential wealth has been translated into limited permanent economic or political power. In fact, wealth or potential for wealth has often made the Navajo the victims of more powerful interests greedy for the assets under limited Navajo control. The primary focus for this education workshop on the radiation effects in the environment is to provide a forum where scientists from the nuclear science and technology community can share their knowledge toward the advancement and diffusion of nuclear science and technology issues for the Navajo public. The scientists will make an attempt to consider the following basic questions; what is science; what is mathematics; what is nuclear radiation? Seven papers are included in this report: Navajo view of radiation; Nuclear energy, national security and international stability; ABC`s of nuclear science; Nuclear medicine: 100 years in the making; Radon in the environment; Bicarbonate leaching of uranium; and Computational methods for subsurface flow and transport. The proceedings of this workshop will be used as a valuable reference materials in future workshops and K-14 classrooms in Navajo communities that need to improve basic understanding of nuclear science and technology issues. Results of the Begay-Stevens research has revealed the existence of strange and mysterious concepts in the Navajo Language of nature. With these research results Begay and Stevens prepared a lecture entitled The Physics of Laser Fusion in the Navajo language. This lecture has been delivered in numerous Navajo schools, and in universities and colleges in the US, Canada, and Alaska

Exposure to depleted uranium does not alter the co-expression of HER-2/neu and p53 in breast cancer patients

<p>Abstract</p> <p>Background</p> <p>Amongst the extensive literature on immunohistochemical profile of breast cancer, very little is found on populations exposed to a potential risk factor such as depleted uranium. This study looked at the immunohistochemical expression of HER-2/neu (c-erbB2) and p53 in different histological types of breast cancer found in the middle Euphrates region of Iraq, where the population has been exposed to high levels of depleted uranium.</p> <p>Findings</p> <p>The present investigation was performed over a period starting from September 2008 to April 2009. Formalin-fixed, paraffin-embedded blocks from 70 patients with breast cancer (62 ductal and 8 lobular carcinoma) were included in this study. A group of 25 patients with fibroadenoma was included as a comparative group, and 20 samples of normal breast tissue sections were used as controls. Labeled streptavidin-biotin (LSAB+) complex method was employed for immunohistochemical detection of HER-2/neu and p53.</p> <p>The detection rate of HER-2/neu and p53 immunohistochemical expression were 47.14% and 35.71% respectively in malignant tumors; expression was negative in the comparative and control groups (p < 0.05).</p> <p>HER-2/neu immunostaining was significantly associated with histological type, tumor size, nodal involvement, and recurrence of breast carcinoma (<it>p </it>< 0.05), p53 immunostaining was significantly associated with tumor size, nodal involvement and recurrence of breast cancer (<it>p </it>< 0.05). There was greater immunoexpression of HER-2/neu in breast cancer in this population, compared with findings in other populations.</p> <p>Both biomarkers were positively correlated with each other. Furthermore, all the cases that co-expressed both HER-2/neu and p53 showed the most unfavorable biopathological profile.</p> <p>Conclusion</p> <p>P53 and HER-2/neu over-expression play an important role in pathogenesis of breast carcinoma. The findings indicate that in regions exposed to high levels of depleted uranium, although p53 and HER-2/neu overexpression are both high, correlation of their expression with age, grade, tumor size, recurrence and lymph node involvement is similar to studies that have been conducted on populations not exposed to depleted uranium. HER-2/neu expression in breast cancer was higher in this population, compared with results on non-exposed populations.</p

Ambulatory care improvement demo project evaluation study.

The Outpatient Department (OPD) of the Alaska Native Medical Center in Anchorage, Alaska offers ambulatory health care services to Alaskan Natives throughout the state. The Outpatient Department focuses on acute and chronic care within the context of all hospital services offered at the Alaska Native Medical Center. Three areas of the OPD were targeted for examination: 1) consumer satisfaction with services provided; 2) identification of areas where Native regional corporations could provide assistance in the development of new programs; and 3) development of a model whereby the Indian Health Service and the Alaska Native Medical Center could work cooperatively with the Cook Inlet Native Association on a five year plan. The scope of the study included consumer satisfaction, a profile of consumer problems, a review of selected day-to-day operational issues, and a review of selected issues of concern to the provider staff. A consumer-oriented and responsive-naturalistic approach was used to evaluate the OPD. Because of the need to develop a cooperative relationship and the desire to address as many functional areas or issues as possible, the methodology for the study was quite subjective. After developing a working relationship with OPD staff, existing data on issues under study was collected and reviewed. Observations were then conducted where appropriate. Interviews were conducted as appropriate and findings were reviewed and analyzed in a series of meetings with study participants. An open-ended Consumer Satisfaction Opinion Poll was conducted in English by researchers with selected participants in the waiting room of the clinic. Additionally, a consumer-problem profile was developed by identifying utilization patterns through review of individual consumer charts. Five hundred sixty-five charts were reviewed by a physician\u27s assistant according to criteria established cooperatively by the study participants. Day-to-day operational issues identified by the study participants were also investigated by several consultants who observed activities and procedures. The recommendation with the highest priority was to add a modular unit to the present OPD and make an additional 2500 to 2700 square feet available. Cook Inlet Native Association recommended that this space be used for an appointment clinic, leaving the present OPD for an emergency and walk-in clinic. This appointment clinic would allow the OPD to adopt a family practice treatment mode. It was also recommended that future resources for ambulatory care should be expended in areas where an impact on Native health status could be expected to result. Further studies on the issues of health education, mental health, social services, and alcoholism, as they relate to ambulatory care services should be investigated. This Phase I study resulted in a broader understanding of the Outpatient Department on the part of the Native consumer and identified areas where improvements could be made

Environmental, policy, and cultural factors related to physical activity in sedentary American Indian women.

Focus group interviews were conducted to explore sociocultural, environmental, and policy-related determinants of physical activity among sedentary American Indian women. Thirty women aged 20 to 50 years (mean = 37.4 +/- 10.6 years) participated. Three sessions were conducted with women aged 20 to 34 years and three with women aged 35 to 50 to evaluate response differences by age. Because no obvious age differences were observed, data were pooled. Barriers to physical activity included inadequate support for household and child care responsibilities and difficulties balancing home-related and societal expectations with physical activity. In addition, women reported little support from their communities and work sites to be physically active. Environmental barriers included lack of safe outdoor areas and accessible walking trails. Weather and stray dogs were also commonly mentioned. Sociocultural barriers included giving family obligations priority above all other things, being expected to eat large portions of high-fat foods, and failing to follow a traditionally active lifestyle. Enablers of physical activity included support from family and coworkers and participation in traditional community events. Suggested intervention approaches included accessible and affordable programs and facilities, community emphasis on physical activity, and programs that incorporated the needs of larger women and of families. Participants emphasized a preference for programs that were compatible with the role expectations of their families and communities, and they expressed the desire for acceptance and encouragement to be physically active from the family, the community, the worksite, and their tribal leaders