58 research outputs found

    Synthesis and Multi-Scale Characterization of Calcium Silicate Hydrate at Multiple CaO/SiO2 Mixture Ratios

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    Calcium Silicate Hydrate (C-S-H) is the primary binding agent that is responsible for setting and hardening, strength, dimensional stability, and durability of Portland cement paste. Although Portland cement hydration produces C-S-H, Calcium hydroxide (CH), ettringite, and other hydration products are also acquired from this process and make it difficult to characterize C-S-H exclusively. C-S-H was first synthesized by mixing calcium oxide (CaO), created by calcining calcium carbonate (CaCO3) that was heated to 950 \xbaC for 24 hours with fumed silica (SiO2) and deionized water (H2O) under nitrogen which produced the synthetic gel-like C-S-H slurry. This composition mixture of synthetic C-S-H was mixed continuously for 7 days with a constant speed and transferred to a filtration system for removal of excess water. The C-S-H gel was then transferred to a drying unit and purged in nitrogen for 5 weeks with a relative humidity (RH) of 11% using Lithium Chloride (LiCl) for 5 weeks. Specimens were obtained by compacting the dried C-S-H powder at 500 MPa. These compacted samples were tested for identifying its mechanical properties on macro, micro, and nano-scale levels. Nanoindentation was used to identify creep compliance and the reduced elastic modulus of C-S-H. Nanoindentation tests confirmed the 0.7 C/S ratio is stiffer (higher elastic modulus) than C-S-H with 1.5 C/S ratio. Furthermore, C-S-H with 0.7 C/S ratio has a lower creep compliance compared with C-S-H with 1.5 C/S ratios. Microstructural investigations using 29Si nuclear magnetic resonance (NMR) and Transmission Electron Microscopes (TEM) were performed on C-S-H specimens. This work shed light on the significance of silicate polymerization in C-S-H on elastic and creep behavior of cement and concrete. This work might lead to developing alternative cements for concrete structures with time-dependent critical applications

    The Science Around Us: creating culturally relevant STEM-H enrichment activities to engage rural students and community.

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    Presented at: NIH SciEd 2016; May 9-12, 2016; Washington, DC.https://digitalrepository.unm.edu/prc-posters-presentations/1027/thumbnail.jp

    FGF21 is a Hormonal Mediator of the Human "Thrifty" Metabolic Phenotype

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    Fibroblast growth factor 21 (FGF21) regulates energy expenditure (EE) and influences weight change after low-protein overfeeding in rodent models. The change in EE after low-protein overfeeding diet is a predictor of weight change in humans and a feature of the "thrifty" metabolic phenotype. However, there are no studies showing an association between circulating FGF21 and EE in humans. We assessed the changes in plasma FGF21 concentrations after 24 hours of seven dietary interventions with different macronutrient content while in a whole-room indirect calorimeter in 64 healthy subjects with normal glucose regulation. Plasma FGF21 concentration consistently increased by 3-fold only after the two low-protein (3%) overfeeding diets, one high in carbohydrate (75%) and the other high in fat (46%), with larger increases in FGF21 being associated with greater increases in 24-h EE. Subjects with smaller increases in FGF21 after the low-protein high-fat diet gained more weight after six months in free-living conditions. Therefore, the individual predisposition to weight gain over time can be assessed by 24-h overfeeding a low-protein diet and measurements of plasma FGF21 concentrations. Individuals with a blunted FGF21 response to a low-protein diet have a thrifty metabolism and are at risk for future weight gain

    Internet Use for Health Information among American Indians: Facilitators and Inhibitors

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    Our research team explored Internet use among a heterogeneous American Indian (AI) population to determine Internet use in relation to health information seeking behaviors. Participants examined an AI culturally-tailored tobacco website as an example to explain what they wanted in an AI Internet health site. Using community-based participatory research, we conducted 10 focus groups with non-college AI men and women (N=96), stratified by age (18-29, 30-49, and 50 and over) to better understand their perceptions of Internet use and health information needs. We found that Internet use varied greatly among all strata. Participants referenced WebMD© more than any other website, but participants were not pleased with the design and navigation. When examining the sample website, participants across strata stressed that recreational and traditional tobacco use should be discussed. Participants in all strata desired a simple website design with easy to read text accompanied by images. In order to gain and maintain cultural respect, participants stated that web designers should be aware that some images hold cultural meaning, particularly tobacco. Baseline data are needed for AI’s use of the Internet to obtain health information; this research is helpful to address health inequalities among AI, particularly access to web-based health information

    Brown Adipose Tissue Response to Cold Stimulation Is Reduced in Girls With Autoimmune Hypothyroidism

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    The interaction between thyroid status and brown adipose tissue (BAT) activation is complex. We assessed the effect of autoimmune hypothyroidism (ATD) in female children on BAT activation, measured using infrared thermography. Participants with ATD had lower resting (hypothyroid, 34.9 +- 0.7°C; control, 35.4 +- 0.5°C; P = 0.03) and stimulated (hypothyroid, 35.0 +- 0.6°C; control, 35.5 +- 0.5°C; P = 0.04) supraclavicular temperatures compared with controls, but there was no difference between groups in the temperature increase with stimulation. BAT activation, calculated as the relative temperature change comparing the supraclavicular temperature to a sternal reference region, was reduced in participants with ATD (hypothyroid, 0.1 +- 0.1°C; control, 0.2 +- 0.2°C; P = 0.04). Children with ATD were frequently biochemically euthyroid due to replacement therapy, but, despite this, increased relative supraclavicular temperature was closely associated with increased TSH (r = 0.7, P = 0.01) concentrations. Girls with ATD had an attenuated thermogenic response to cold stimulation compared with healthy controls, but, contrary to expectation, those with suboptimal biochemical control (with higher TSH) showed increased BAT activation. This suggests that the underlying disease process may have a negative effect on BAT response, but high levels of TSH can mitigate, and even stimulate, BAT activity. In summary, thyroid status is a complex determinant of BAT activity in girls with ATD.This work was supported by a pump-priming grant from Nottingham University Hospitals Charity (Grant PP-Law-Nov12)

    Resources for Native Education Leaders

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    This resource guide lists institutions and programs, dissertations, articles, and books about Native American education leadership in Native organizations and communitites. It also includes citations from Leadership Quarterly on the same subject. Vol. 13, Issue 4, Summer 2002. Educational levels: Undergraduate upper division, Undergraduate upper division, Graduate or professional

    Beulah Allen: Emergency Medical Service for the Navajo Nation.

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    An interview of Beulah Allen, a Navajo Medical Doctor. This video is a part of the WSU Mass Communication Navajo Oral Histories Series
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