746 research outputs found

    Thermal Surveillance: Do Infrared Eyes in the Sky Violate the Fourth Amendment?

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    Understanding the Transition between High School and College Mathematics and Science

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    Mathematics and science education is gaining increasing recognition as key for the well-being of individuals and society. Accordingly, the transition from high school to college is particularly important to ensure that students are prepared for college mathematics and science. The goal of this study was to understand how high school mathematics and science course-taking related to performance in college. Specifically, the study employed a nonparametric regression method to examine the relationship between high school mathematics and science courses, and academic performance in college mathematics and science courses. The results provide some evidence pertaining to the positive benefits from high school course-taking. Namely, students who completed high school trigonometry and lab-based chemistry tended to earn higher grades in college algebra and general chemistry, respectively. However, there was also evidence that high school coursework in biology and physics did not improve course performance in general biology and college physics beyond standardized test scores. Interestingly, students who completed high school calculus earned better grades in general biology. The implications of the findings are discussed for high school curriculum and alignment in standards between high schools and colleges

    Tumor vasculature and microenvironment during progression and treatment : insights from optical microscopy

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    Thesis (Ph. D.)--Harvard-MIT Division of Health Sciences and Technology, February 2010.Vita. Cataloged from PDF version of thesis.Includes bibliographical references.In addition to cancer cells, solid tumors consist of a variety of cell types and tissues defining a complex microenvironment that influences disease progression and response to therapy. To fully characterize and probe the tumor microenvironment, new tools are needed to quantitatively assess microanatomical and physiological changes during tumor growth and treatment. Particularly important, is the metabolic microenvironment defined in tumors by hypoxia (low p02) and acidity (low pH). These parameters have been shown to influence response to radiation therapy and chemotherapy. However, very little is known about spatio-temporal changes in p02 and pH during tumor progression and therapy. By modifying the technique of intravital multiphoton microscopy (MPM) to perform phosphorescence quenching microscopy, I developed a non-invasive method to quantify oxygen tension (p02) in living tissue at high three-dimensional resolution. To probe functional changes in the metabolic microenvironment, I measured in vivo P02 during tumor growth and antiangiogenic (vascular targeted) treatment in preclinical tumor models. Nanotechnology is rapidly emerging as an important source of biocompatible tools that may shape the future of medical practice. Fluorescent semiconductor nanocrystals (NCs), also known as quantum dots, are a powerful tool for biological imaging, cellular targeting and molecular sensing.(cont.) I adapted novel fluorescence resonance energy transfer (FRET) -based nanocrystal (NC) biosensors for use with MPM to qualitatively measure in vivo extracellular pH in tumors at high-resolution. While intravital multiphoton microscopy demonstrates utility and adaptability in the study of cancer and response to therapy, the requisite high numerical aperture and exogenous contrast agents result in a limited capacity to investigate substantial tissue volumes or probe dynamic changes repeatedly over prolonged periods. By applying optical frequency domain imaging (OFDI) as an intravital microscopic tool, the technical limitations of multiphoton microscopy can be circumvented providing unprecedented access to previously unexplored, critically important aspects of tumor biology. Using entirely intrinsic mechanisms of contrast within murine tumor models, OFDI is able to simultaneously, rapidly, and repeatedly probe the microvasculature, lymphatic vessels, and tissue microstructure and composition over large volumes. Using OFDI-based techniques, measurements of tumor angiogenesis, lymphangiogenesis, tissue viability and both vascular and cellular responses to therapy were demonstrated, thereby highlighting the potential of OFDI to facilitate the exploration of pathophysiological processes and the evaluation of treatment strategies.by Ryan M. Lanning.Ph.D

    Communication Skills Instruction Utilizing Interdisciplinary Peer Teachers: Program Development and Student Perceptions

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    Lack of curricular time, faculty time, and funding are potential limitations for communication skills training in dentistry. Interdisciplinary collaboration amongst health care faculties could address these limitations. This article describes the development, implementation, and student perceptions of a communication skills program in dentistry. The program has four components: Knowledge, Observation, Simulation, and Experience (KOSE) and spans over the second and third years of dental school. KOSE allows students to obtain knowledge of and observe effective communication skills and practice these skills in the simulated and nonsimulated environment. A key feature of KOSE is the utilization of fourth-year medical and dental students as peer teachers. Evaluation of KOSE was geared toward student perceptions. Cross-sectional data were gathered via written surveys from 143 learners (second- and third-year dental students) in 2006–07. Students perceived the ability to recognize effective communication, demonstrated awareness of their communication strengths and weaknesses, and reported that skills gained were transferable to actual patient care. Interdisciplinary collaboration was a feasible way to address the lack of resources in the development of a communications skills program, which was perceived to be worthwhile by learners

    Observation of Porosity Reduction in a Densification-Prone Test Fuel Rod: Data and Analysis

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    Instrumented fuel assembly (IFA)-431 was irradiated in the Halden Boiling Water Reactor (HBWR) for the purpose of extending the steady-state data base. Rod 6 of this assembly began irradiation with UO{sub 2} fuel of 92% theoretical density (TD) that was unstable with respect to in-reactor densification. Thermal resintering tests resulted in a final density of 95.3% TD while post-irradiation examination (PIE) indicated a final density of 96.5% TD. Observed microstructural changes were consistent with published densification studies; there was a marked depletion of submicrometer diameter pores and total pore volume. However, grain size increased only slightly, indicating that internal pellet temperatures did not reach the 1875K applied in resintering tests. Oensification was observed to increase the temperatures in rod 6, but temperatures did not become as high as for a sibling rod that simulated instantaneous densification. Temperatures calculated with U.S. Nuclear Regulatory Commission (NRC) fuel performance computer codes were generally higher than observed temperatures

    Feasibility of Utilizing Social Media to Promote HPV Self‐Collected Sampling Among Medically Underserved Women in a Rural Southern City in the United States (U.S.)

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    Background: Social media (Facebook, WhatsApp, Instagram, Twitter) as communication channels have great potential to deliver Human papillomavirus self‐test (HPVST) intervention to medically underserved women (MUW) such as women of low income. However, little is known about MUW’s willingness to participate in HPVST intervention delivered through social media. We evaluated factors that contribute to MUW’s intention to participate in the social media‐related intervention for HPVST. Methods: A 21‐item survey was administered among women receiving food from a local food pantry in a U.S. southern state. Independent variables were social media usage facilitators (including confidentiality, social support, cost, and convenience), and barriers (including misinformation, time‐consuming, inefficient, and privacy concerns). Dependent variables included the likelihood of participating in social‐driven intervention for HPVST. Both variables were measured on a 5‐point scale. We used multinomial logistic regression to analyze the data. Results: A total of 254 women (mean age 48.9 ± 10.7 years) comprising Whites (40%), Hispanics (29%), Blacks (27%), and Other (4%) participated in the study. We found that over 44% of the women were overdue for their pap smears for the past three years, 12% had never had a pap smear, and 34% were not sure if they had had a pap smear. Over 82% reported frequent social media (e.g., Facebook) usage, and 52% reported willingness to participate in social media‐driven intervention for HPVST. Women who reported that social media provide privacy (Adjusted Odds Ratio (AOR) = 6.23, 95% CI: 3.56, 10.92), provide social support (AOR = 7.18, 95% CI: 4.03, 12.80), are less costly (AOR = 6.71, 95% CI: 3.80, 11.85), and are convenient (AOR = 6.17, 95% CI: 3.49, 10.92) had significantly increased odds of participating in social media intervention for HPVST. Conclusions: The findings underscore that the majority of the MUW are overdue for cervical cancer screening, regularly use social media, and are willing to participate in social media‐driven intervention. Social media could be used to promote HPV self‐testing among MUW

    Immunolocalization of KATP channel subunits in mouse and rat cardiac myocytes and the coronary vasculature.

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    BACKGROUND: Electrophysiological data suggest that cardiac KATP channels consist of Kir6.2 and SUR2A subunits, but the distribution of these (and other KATP channel subunits) is poorly defined. We examined the localization of each of the KATP channel subunits in the mouse and rat heart. RESULTS: Immunohistochemistry of cardiac cryosections demonstrate Kir6.1 protein to be expressed in ventricular myocytes, as well as in the smooth muscle and endothelial cells of coronary resistance vessels. Endothelial capillaries also stained positive for Kir6.1 protein. Kir6.2 protein expression was found predominantly in ventricular myocytes and also in endothelial cells, but not in smooth muscle cells. SUR1 subunits are strongly expressed at the sarcolemmal surface of ventricular myocytes (but not in the coronary vasculature), whereas SUR2 protein was found to be localized predominantly in cardiac myocytes and coronary vessels (mostly in smaller vessels). Immunocytochemistry of isolated ventricular myocytes shows co-localization of Kir6.2 and SUR2 proteins in a striated sarcomeric pattern, suggesting t-tubular expression of these proteins. Both Kir6.1 and SUR1 subunits were found to express strongly at the sarcolemma. The role(s) of these subunits in cardiomyocytes remain to be defined and may require a reassessment of the molecular nature of ventricular KATP channels. CONCLUSIONS: Collectively, our data demonstrate unique cellular and subcellular KATP channel subunit expression patterns in the heart. These results suggest distinct roles for KATP channel subunits in diverse cardiac structures
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