448 research outputs found

    NASA Administrative Data Base Management Systems, 1984

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    Strategies for converting to a data base management system (DBMS) and the implementation of the software packages necessary are discussed. Experiences with DBMS at various NASA centers are related including Langley's ADABAS/NATURAL and the NEMS subsystem of the NASA metrology informaton system. The value of the integrated workstation with a personal computer is explored

    Nitrosative stress induces DNA strand breaks but not caspase mediated apoptosis in a lung cancer cell line

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    BACKGROUND: Key steps crucial to the process of tumor progression are genomic instability and escape from apoptosis. Nitric oxide and its interrelated reactive intermediates (collectively denoted as NO(X)) have been implicated in DNA damage and mutational events leading to cancer development, while also being implicated in the inhibition of apoptosis through S-nitrosation of key apoptotic enzymes. The purpose of this study was to explore the interrelationship between NO(X)-mediated DNA strand breaks (DSBs) and apoptosis in cultured tumor cell lines. METHODS: Two well-characterized cell lines were exposed to increasing concentrations of exogenous NO(X )via donor compounds. Production of NO(X )was quantified by the Greiss reaction and spectrophotometery, and confirmed by nitrotyrosine immunostaining. DSBs were measured by the alkaline single-cell gel electrophoresis assay (the COMET assay), and correlated with cell viability by the MTT assay. Apoptosis was analyzed both by TUNEL staining and Annexin V/propidium iodine FACS. Finally, caspase enzymatic activity was measured using an in-vitro fluorogenic caspase assay. RESULTS: Increases in DNA strand breaks in our tumor cells, but not in control fibroblasts, correlated with the concentration as well as rate of release of exogenously administered NO(X). This increase in DSBs did not correlate with an increase in cell death or apoptosis in our tumor cell line. Finally, this lack of apoptosis was found to correlate with inhibition of caspase activity upon exposure to thiol- but not NONOate-based NO(X )donor compounds. CONCLUSIONS: Genotoxicity appears to be highly interrelated with both the concentration and kinetic delivery of NO(X). Moreover, alterations in cell apoptosis can be seen as a consequence of the explicit mechanisms of NO(X )delivery. These findings lend credence to the hypothesis that NO(X )may play an important role in tumor progression, and underscores potential pitfalls which should be considered when developing NO(X)-based chemotherapeutic agents

    Pengembangan Media Pembelajaran Matematika Berbantu Wondershare dengan Pendekatan Rme pada Materi SMP

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    Pemilihan media pembelajaran yang kurang tepat dapat membuat siswa kurang antusias terhadap mata pelajaran matematika. Sehingga banyak siswa yang mendapat nilai dibawah KKM. Solusinya dibutuhkan media pembelajaran yang menarik serta dapat menumbuhkan antusias siswa dalam belajar.Penelitian ini bertujuan untuk mengembangkan media pembelajaran berbantu wondershare dengan pendekatan RME sehingga menghasilkan media yang layak dan efektif digunakan selama pembelajaran. Jenis penelitian ini adalah penelitian Research and Development dengan menggunakan model pengembangan ADDIE, terdiri dari 5 tahapan yaitu analisis, design, developmen, implementasi, evaluasi.Sebelum diimplementasikan, media pembelajaran terlebih dahulu dilakukan uji validasi oleh ahli media, ahli materi serta angket tanggapan siswa. Hasil validasi ahli tersebut berkriteria sangat baik sehingga media pembelajaran layak untuk digunakan.Pembelajaran dengan media pembelajaran berbantu wondershare dengan pendekatan RME efektif digunakan oleh peserta didik. Hal ini di buktikan dari rata rata kelas eksperimen dan kontrol yaitu 82,03 dan 60,54. Ketuntasan belajar individu kelas ekperimen terdapat 31 siswa tuntas dari 36 siswa, dan kelas kontrol terdapat 8 siswa tuntas dari 27 siswa. Dilihat dari ketuntasan belajar klasikal siswa untuk kelas kontrol dan eksperimen sebesar 22,86% dan 86,11%. Dengan analisis menggunakan uji t pihak kanan diperoleh nilaiyaitu 9,607>1,667 maka H0 ditolak, jadi pembelajaran dengan menggunakan media pembelajaran berbantuan wondershare dengan pendekatan RME lebih baik dibandingkan dengan pembelajaran konvensional pada materi SMP

    Rectal Optical Markers for In-vivo Risk Stratification of Premalignant Colorectal Lesions.

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    Purpose: Colorectal cancer remains the second leading cause of cancer deaths in the U.S. despite being eminently preventable by colonoscopy via removal of premalignant adenomas. In order to more effectively reduce colorectal cancer mortality, improved screening paradigms are needed. Our group pioneered the use of low coherence enhanced backscattering (LEBS) spectroscopy to detect the presence of adenomas throughout the colon via optical interrogation of the rectal mucosa. In a previous ex-vivo biopsy study of 219 patients, LEBS demonstrated excellent diagnostic potential with 89.5% accuracy for advanced adenomas. The objective of the current cross-sectional study is to assess the viability of rectal LEBS in-vivo. Experimental Design: Measurements from 619 patients were taken using a minimally invasive 3.4 mm diameter LEBS probe introduced into the rectum via anoscope or direct insertion, requiring ~1 minute from probe insertion to withdrawal. The diagnostic LEBS marker was formed as a logistic regression of the optical reduced scattering coefficient μs∗ and mass density distribution factor D. Results: The rectal LEBS marker was significantly altered in patients harboring advanced adenomas and multiple non-advanced adenomas throughout the colon. Blinded and cross-validated test performance characteristics showed 88% sensitivity to advanced adenomas, 71% sensitivity to multiple non-advanced adenomas, and 72% specificity in the validation set. Conclusions: We demonstrate the viability of in-vivo LEBS measurement of histologically normal rectal mucosa to predict the presence of clinically relevant adenomas throughout the colon. The current work represents the next step in the development of rectal LEBS as a tool for colorectal cancer risk stratification

    Skeletal Light-Scattering Accelerates Bleaching Response in Reef-Building Corals

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    Background At the forefront of ecosystems adversely affected by climate change, coral reefs are sensitive to anomalously high temperatures which disassociate (bleaching) photosynthetic symbionts (Symbiodinium) from coral hosts and cause increasingly frequent and severe mass mortality events. Susceptibility to bleaching and mortality is variable among corals, and is determined by unknown proportions of environmental history and the synergy of Symbiodinium- and coral-specific properties. Symbiodinium live within host tissues overlaying the coral skeleton, which increases light availability through multiple light-scattering, forming one of the most efficient biological collectors of solar radiation. Light-transport in the upper ~200 μm layer of corals skeletons (measured as ‘microscopic’ reduced-scattering coefficient, μ′S,m), has been identified as a determinant of excess light increase during bleaching and is therefore a potential determinant of the differential rate and severity of bleaching response among coral species. Results Here we experimentally demonstrate (in ten coral species) that, under thermal stress alone or combined thermal and light stress, low-μ′S,m corals bleach at higher rate and severity than high-μ′S,m corals and the Symbiodinium associated with low-μ′S,m corals experience twice the decrease in photochemical efficiency. We further modelled the light absorbed by Symbiodinium due to skeletal-scattering and show that the estimated skeleton-dependent light absorbed by Symbiodinium (per unit of photosynthetic pigment) and the temporal rate of increase in absorbed light during bleaching are several fold higher in low-μ′S,m corals. Conclusions While symbionts associated with low-μ′S,m corals receive less total light from the skeleton, they experience a higher rate of light increase once bleaching is initiated and absorbing bodies are lost; further precipitating the bleaching response. Because microscopic skeletal light-scattering is a robust predictor of light-dependent bleaching among the corals assessed here, this work establishes μ′S,m as one of the key determinants of differential bleaching response

    Effects of a Water-Soluble Cinnamon Extract on Body Composition and Features of the Metabolic Syndrome in Pre-Diabetic Men and Women

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    Purpose: The purpose of this study was to determine the effects of supplementation with a water-soluble cinnamon extract (Cinnulin PF®) on body composition and features of the metabolic syndrome. Methods: Twenty-two subjects with prediabetes and the metabolic syndrome (mean ± SD: age, BMI, systolic blood pressure [SBP], fasting blood glucose [FBG]: 46.0 ± 9.7 y; 33.2 ± 9.3 kg/m 2; 133 ± 17 mm Hg; 114.3 ± 11.6 mg/dL) were randomly assigned to supplement their diet with either Cinnulin PF ® (500 mg/d) or a placebo for 12-weeks. Main outcome measures were changes in FBG, SBP, and body composition measured after 12-weeks of supplementation. The primary statistical analyses consisted of two factor (group x time), repeated-measures ANOVA for between group differences over time. In all analyses, an intent-to-treat approach was used and significance was accepted at P<0.05. Results: Subjects in the Cinnulin PF ® group had significant decreases in FBG (-8.4%: 116.3 ± 12.8 mg/dL [pre] to 106.5 ± 20.1 mg/dL [post], p<0.01), SBP (-3.8%: 133 ± 14 mm Hg [pre] to 128 ± 18 mm Hg [post], p<0.001), and increases in lean mass (+1.1%: 53.7 ± 11.8 kg [pre] to 54.3 ± 11.8 kg [post], p<0.002) compared with the placebo group. Additionally, within-group analyses uncovered small, but statistically significant decreases in body fat (-0.7%: 37.9 ± 9.2 % [pre] to 37.2 ± 8.9 % [post], p<0.02) in the Cinnulin PF ® group. No significant changes in clinical blood chemistries were observed betwee
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