1,098 research outputs found

    Wind tunnel calibration of the ''Arcasonde 1-A'' at simulated altitudes between 35 and 57 km

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    Subsonic wind tunnel calibration of Arcasonde 1-A atmospheric temperature sensing unit at simulated altitudes between 35 and 56 k

    Exploring Students’ Perceptions of their Experiences in a Social Justice Living–Learning Community

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    Contemporary higher education leaders continue to deem the development of civic-minded graduates as among the primary goals of postsecondary education (Astin, 1996Astin, H. S. (1996). Leadership for social change. About Campus, 1(3), 4–10. doi:10.1002/abc.v1.3[Crossref] , [Google Scholar]; Cress, Burack, Giles, Elkins, & Stevens, 2010Cress, C., Burack, C., Giles, D. E., Elkins, J. E., & Stevens, M. C. (2010). A promising connection: Increasing college access and success through civic engagement. Boston, MA: Campus Compact. [Google Scholar]; Hurtado, Ruiz, & Whang, 2012Hurtado, S., Ruiz, A., & Whang, H. (2012). Assessing student social responsibility and civic learning. Paper presented at the 2012 Annual Forum of the Association for Institutional Research, New Orleans, Louisiana. [Google Scholar]). Today’s undergraduates are poised to engage with their communities in numbers greater than their predecessors in previous generations, believing it is their responsibility to make society better (Kiesa et al., 2007Kiesa, A., Orlowski, A. P., Levine, P., Both, D., Kirby, E. H., Lopez, M. H., & Marcelo, K. B. (2007). Millennials talk politics: A study of college student political engagement. New York, NY: The Center for Information & Research on Civic Learning & Engagement. [Google Scholar]). In 2012, more than two-thirds of postsecondary students reported participation in community service over the past year, despite their overwhelming disillusionment with the United States government and social institutions (Levine & Dean, 2012Levine, A., & Dean, D. R. (2012). Generation on a tightrope: A portrait of today’s college student. San Francisco, CA: Wiley. [Google Scholar]) Civic engagement lacks a common definition in the literature (Jacoby, 2009Jacoby, B. (Ed.). (2009). Civic engagement in higher education: Concepts and practices. San Francisco, CA: Jossey-Bass. [Google Scholar]), however it typically includes involvement in the community with the purpose of “enhancing students’ understanding of civic life” (Cress et al., 2010Cress, C., Burack, C., Giles, D. E., Elkins, J. E., & Stevens, M. C. (2010). A promising connection: Increasing college access and success through civic engagement. Boston, MA: Campus Compact. [Google Scholar], p. 4). A growing body of research raised concerns with community service, service-learning, and other forms of civic engagement as reinforcing stereotypes (Dooley & Burant, 2015Dooley, J. C., & Burant, T. J. (2015). Lessons from pre-service teachers: Under the surface of service learning. In O. Delano-Oriaran, M. Penick-Parks, & S. Fondrie (Eds.), Service-learning and civic engagement: A sourcebook (pp. 325–332). Thousand Oaks, CA: SAGE Publications.[Crossref] , [Google Scholar]). These studies urged greater care when designing community involvement opportunities, including attention to students’ development and previous experience, meaningful curricular connections, and adequate contextualization and reflection (Dooley & Burant, 2015Dooley, J. C., & Burant, T. J. (2015). Lessons from pre-service teachers: Under the surface of service learning. In O. Delano-Oriaran, M. Penick-Parks, & S. Fondrie (Eds.), Service-learning and civic engagement: A sourcebook (pp. 325–332). Thousand Oaks, CA: SAGE Publications.[Crossref] , [Google Scholar]). Some campuses have linked social justice to civic engagement to advance students’ knowledge about inequity, thus moving them away from a savior orientation (Dooley & Burant, 2015Dooley, J. C., & Burant, T. J. (2015). Lessons from pre-service teachers: Under the surface of service learning. In O. Delano-Oriaran, M. Penick-Parks, & S. Fondrie (Eds.), Service-learning and civic engagement: A sourcebook (pp. 325–332). Thousand Oaks, CA: SAGE Publications.[Crossref] , [Google Scholar]) and deepening their understanding of the experience (Prentice, 2007Prentice, M. (2007). Service-learning and civic engagement. Academic Questions, 20(2), 135–145. doi:10.1007/s12129-007-9005-y[Crossref] , [Google Scholar]). Although conceptualized in varying ways, for this article social justice is defined as work toward ending the system of oppression giving certain social groups greater privilege and power over other groups (Broido, 2000Broido, E. M. (2000). The development of social justice allies during college: A phenomenological investigation. Journal of College Student Development, 41(1), 3–18.[Web of Science ¼] , [Google Scholar]). When coupled, the terms civic engagement and social justice often indicate the educators’ desire to situate students in their broader communities and increase their awareness of social inequity, which may inspire them to work for social change at the individual, cultural, and institutional levels (Boyle-Baise & Langford, 2004Boyle-Baise, M., & Langford, J. (2004). There are children here: Service learning for social justice. Equity & Excellence in Education, 37(1), 55–66. doi:10.1080/10665680490422115[Taylor & Francis Online], [Web of Science ¼] , [Google Scholar]). Living–learning communities (LLCs) are increasingly utilized to deepen and cohere students’ collegiate experiences (Matthews, Smith, & MacGregor, 2012Matthews, R. S., Smith, B. L., & MacGregor, J. (2012). The evolution of learning communities: A retrospective. In K. Buch & K. E. Barron (Eds.), New directions for teaching and learning: No. 132. Discipline centered learning communities (pp. 99–111). San Francisco, CA: Jossey-Bass.[Crossref] , [Google Scholar]). Although variation exists in thematic and organizational type, these communities typically group students together in a residence hall, offer a shared academic experience, and provide co-curricular activities related to a theme (Inkelas & Soldner, 2011Inkelas, K. K., & Soldner, M. (2011). Undergraduate living–learning programs and student outcomes. Higher Education: Handbook of Theory and Research, 26, 1–55.[Crossref] , [Google Scholar]). Social justice LLCs, which focus on increasing students’ awareness of social inequity and providing them with opportunities to work for social change, are often found on college campuses (Inkelas, 2007Associates; Inkelas, K. K. (2007). National study of living–learning programs: 2007 report of findings. College Park, MD: Authors. [Google Scholar]). Yet little formal research has been done that explores the impact of these communities on students. Thus, the purpose of this study was to explore students’ experiences throughout their time in a social justice-focused LLC (hereafter referred by the pseudonym SJLLC) and one year after participation, focusing on how students described their participation in SJLLC and what aspects of the LLC had a lasting impression on them

    The Effects of Supplemental Fish Oil on Blood Pressure and Morning Cortisol in Normotensive Adults: A Pilot Study

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    Purpose: To determine the effects of 6wk of supplementation with fish oil (FO) on blood pressure and the morning salivary cortisol concentration in normotensive adults. Methods: Testing was performed following an overnight fast. Subjects (n=40; 35+/-13y, mean+/-SD) rested supine for 40 min, at which time blood pressure and heart rate were measured. Saliva was collected and analyzed for cortisol. Subjects were then randomly assigned to either: 4g/d of Safflower Oil (SO); pr 4g/d of FO supplying 1,600mg/d eicosapentaenoic acid and 800mg/d docosahexaenoic acid. Testing was repeated following 6wk treatment. Results: Compared to SO, there was a significant decrease in systolic blood pressure with FO (SO= 1.3+/-5.8 mmHg; FO= -6.8+/-10.2 mmHg; p=0.004), a significant reduction in pulse pressure with FO (SO= 0.2+/-7.8 mmHg; FO= -6.4+/-8.8 mmHg; p=0.02), and a tendency for a decrease in mean arterial pressure (SO= 1.2+/-5.3 mmHg; FO= -2.5+/-7.3 mmHg; p=0.08). There was a tendency for salivary cortisol to decrease with FO (SO= 0.005+/-0.129 ”g/dL; FO= -0.068+/-0.148 ”g/dL; p=0.072), however, this change was not significant;y correlated with the change in systolic blood pressure (r=0.021, p=0.929). Conclusion: 6wk of supplementation with FO significantly decreases systolic blood pressure in normotensive adults and this change was not significantly correlated with a reduction in salivary cortisol

    Supplemental fish oil decreases urinary excretion of a marker of bone resorption in healthy adults

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    Background: Incorporation of fish oil (FO) into the diet of rodents has been shown to result in positive changes in bone health. Currently it is poorly understood if FO has the same effects on bone health in humans. The purpose of this study was to determine the effects of supplemental FO on levels of urinary N-terminal cross-linked telopeptide (NTx), which is a marker of bone breakdown, and how this is related to the morning levels of salivary cortisol and urinary excretion of interleukin 6 (IL-6). Methods: A total of twenty-eight females and twelve males(35 ± 13yrs; 69.1 ± 14.1kg; 29.4 ± 9.2% body fat; mean ± SD) participated in this study. All testing was conducted in the morning following an overnight fast. Baseline measurements of salivary cortisol were collected via passive drool and baseline measurements of urinary NTxand IL- 6 were collected from the second void of the day and corrected for creatinine excretion. After baseline testing, subjects were assigned randomly in a double blind manner to one of two groups: 4 g/d of Safflower Oil (SO) or 4 g/d of FO supplying 1,600 mg/d eicosapentaenoic acid (EPA) and 800 mg/d docosahexaenoic acid (DHA). All tests were repeated following 6wk of treatment. A treatment by time, repeated measures ANOVA was used to evaluate differences between groups over time, and a standard Pearson’s r was used to evaluate correlations. Additionally, within group pre-post differences were evaluated using a repeated measures t-test. For all analysis, the alpha level was set at p\u3c0.05. Results: Compared to the SO group, there was a significant decrease in urinary creatinine corrected NTx excretion following FO treatment (SO = 17.5 ± 42.9 BCE/mM; FO = -11.3 ± 27.7 BCE/mM; p=0.02). There was also a tendency for urinary creatinine corrected IL-6 excretion (SO = -0.08 ± 1.18pg/mg; FO = -1.8 ± 3.8 pg/mg; p=0.08), and salivary cortisol (SO = 0.029±0.283 ÎŒg/dL; FO = -0.069 ± 0.144 ÎŒg/dL; p=0.13) to decrease following FO treatment.When analyzed independently, however, there was a significant pre-post reduction for salivary cortisol in the FO group (p=0.04), with no change in the SO group (p=0.68), as well as a significant reduction pre-post for urinary IL-6 in the FO group (p=0.05), with no change in the SO group (p=0.78). However, the change in urinary NTx concentrationwas not related to the change insalivary cortisol concentration( r=-0.017, p=0.9), or the change in urinary IL-6 concentration (r=-0.323, p=0.26). Conclusions: Six weeks of supplementation with FO in adults significantly decreased urinary NTx excretion, but this change was not related to changes in cortisol or IL-6

    Targeted Stimuli-Responsive Dextran Conjugates for Doxorubicin Delivery to Hepatocytes

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    A targeted, stimuli-responsive, polymeric drug delivery vehicle is being developed in our lab to help alleviate severe side-effects caused by narrow therapeutic window drugs. Targeting specific cell types or organs via proteins, specifically, lectin-mediated targeting holds potential due to the high specificity and affinity of receptor-ligand interactions, rapid internalization, and relative ease of processing. Dextran, a commercially available, biodegradable polymer has been conjugated to doxorubicin and galactosamine to target hepatocytes in a three-step, one-pot synthesis. The loading of doxorubicin and galactose on the conjugates was determined by absorbance at 485 nm and elemental analysis, respectively. Conjugation efficiency based on the amount loaded of each reactant varies from 20% to 50% for doxorubicin and from 2% to 20% for galactosamine. Doxorubicin has also been attached to dextran through an acid-labile hydrazide bond. Doxorubicin acts by intercalating with DNA in the nuclei of cells. The fluorescence of doxorubicin is quenched when it binds to DNA. This allows a fluorescence-based cell-free assay to evaluate the efficacy of the polymer conjugates where we measure the fluorescence of doxorubicin and the conjugates in increasing concentrations of calf thymus DNA. Fluorescence quenching indicates that our conjugates can bind to DNA. The degree of binding increases with polymer molecular weight and substitution of doxorubicin. In cell culture experiments with hepatocytes, the relative uptake of polymer conjugates was evaluated using flow cytometry, and the killing efficiency was determined using the MTT cell proliferation assay. We have found that conjugate uptake is much lower than that of free doxorubicin. Lower uptake of conjugates may increase the maximum dose of drug tolerated by the body. Also, non-galactosylated conjugate uptake is lower than that of the galactosylated conjugate. Microscopy indicates that doxorubicin localizes almost exclusively at the nucleus, whereas the conjugates are present throughout the cell. Doxorubicin linked to dextran through a hydrazide bond was used to achieve improved killing efficiency. Following uptake, the doxorubicin dissociates from the polymer in an endosomal compartment and diffuses to the nucleus. The LC₅₀ of covalently linked doxorubicin is 7.4 ÎŒg/mL, whereas that of hydrazide linked doxorubicin is 4.4 ÎŒg/mL.Singapore-MIT Alliance (SMA

    Recovery from a cycling time trial is enhanced with carbohydrate-protein supplementation vs. isoenergetic carbohydrate supplementation

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    Background: In this study we assessed whether a liquid carbohydrate-protein (C+P) supplement (0.8 g/kg C; 0.4 g/kg P) ingested early during recovery from a cycling time trial could enhance a subsequent 60 min effort on the same day vs. an isoenergetic liquid carbohydrate (CHO) supplement (1.2 g/kg). Methods: Two hours after a standardized breakfast, 15 trained male cyclists completed a time trial in which they cycled as far as they could in 60 min (AMex) using a Computrainer indoor trainer. Following AMex, subjects ingested either C+P, or CHO at 10, 60 and 120 min, followed by a standardized meal at 4 h post exercise. At 6 h post AMex subjects repeated the time trial (PMex). Results: There was a significant reduction in performance for both groups in PMex versus AMex. However, performance and power decreases between PMex and AMex were significantly greater (p ≀ 0.05) with CHO (-1.05 ± 0.44 km and -16.50 ± 6.74 W) vs C+P (-0.30 ± 0.50 km and -3.86 ± 6.47 W). Fat oxidation estimated from RER values was significantly greater (p ≀ 0.05) in the C+P vs CHO during the PMex, despite a higher average workload in the C+P group. Conclusion: Under these experimental conditions, liquid C+P ingestion immediately after exercise increases fat oxidation, increases recovery, and improves subsequent same day, 60 min efforts relative to isoenergetic CHO ingestion

    Ligand Valency Affects Transcytosis, Recycling and Intracellular Trafficking Mediated by the Neonatal Fc Receptor

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    The neonatal Fc receptor (FcRn) transports IgG across epithelial cell barriers to provide maternal antibodies to offspring and serves as a protection receptor by rescuing endocytosed IgG and albumin from lysosomal degradation. Here we describe the generation of polarized Madin–Darby canine kidney (MDCK) cells expressing rat FcRn (rFcRn) to investigate the potential requirement for ligand bivalency in FcRn-mediated transport. The rFcRn-MDCK cells bind, internalize and bidirectionally transcytose the bivalent ligands IgG and Fc across polarized cell monolayers. However, they cannot be used to study FcRn-mediated transport of the monovalent ligand albumin, as we observe no specific binding, internalization or transcytosis of rat albumin. To address whether ligand bivalency is required for transport, the ability of rFcRn to transcytose and recycle wild-type Fc homodimers (wtFc; two FcRn-binding sites) and a heterodimeric Fc (hdFc; one FcRn-binding site) was compared. We show that ligand bivalency is not required for transcytosis or recycling, but that wtFc is transported more efficiently than hdFc, particularly at lower concentrations. We also demonstrate that hdFc and wtFc have different intracellular fates, with more hdFc than wtFc being trafficked to lysosomes and degraded, suggesting a role for avidity effects in FcRn-mediated IgG transport
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