785 research outputs found

    Come, Lord of Glory

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    Elementary Teachers Committed to Actively Teaching Science and Engineering

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    Committed elementary teachers of science and engineering, members of a professional learning community called Collaborative Conversations in STEM, were studied to elicit their perceptions of experiences that influenced their commitment to, and their pedagogical content knowledge of, STEM teaching and learning

    Study of Apollo water impact. Volume 8 - Unsymmetric shells of revolution analysis Final report

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    Numerical analysis of static, and dynamic shell response to water impact load

    5 Równoczasowa chemioterapia chorych na drobnokomórkowego raka płuc (DKRP) w postaci ograniczonej. Doświadczenia własne w pilotowej grupie 32 chorych

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    W styczniu 1994 roku w Krakowskim Centrum Onkologii rozpoczęto prospektywne badanie II fazy celem oceny skuteczności i toksyczności równoczesnego leczenia chemicznego wg schematu EP (etopozyt + cysplatyna) i napromienianiem chorych na DKRP w postaci ograniczonej. Do lutego 1998 roku zakończono leczenie 32 chorych. W całej grupie uzyskano 21% 3-letnich aktualizowanych przeżyć bezobjawowych. Przeprowadzono analizę wpływu na wyniki leczenia takich czynników jak: profilaktyczne napromienianie mózgu, opóźnienie radioterapii w stosunku do leczenia chemicznego, liczba serii chemioterapii, zaawansowanie kliniczne według TNM, obecność regresji potwierdzonej w badaniu histologicznym. Uzyskane wyniki wstępne wskazują na konieczność dalszych modyfikacji protokołu leczenia

    Evaluation of the fidelity of feature descriptor-based specimen tracking for automatic NDE data integration

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    This research addresses inspection location tracking in the field of nondestructive evaluation (NDE) using a computer vision technique to determine the position and orientation of typical NDE equipment in a test setup. The objective is the tracking accuracy for typical NDE equipment to facilitate automatic NDE data integration. Since the employed tracking technique relies on surface curvatures of an object of interest, the accuracy can be only experimentally determined. We work with flash-thermography and conducted an experiment in which we tracked a specimen and a thermography flash hood, measured the spatial relation between both, and used the relation as input to map thermography data onto a 3D model of the specimen. The results indicate an appropriate accuracy, however, unveiled calibration challenges

    Two Enabling Strategies for the Stereoselective Conversion of Internal Alkynes into Trisubstituted Alkenes

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    An expedient method for the C-methylation of alkenylstannanes with formation of trisubstituted alkenes is described, which relies on the use of MeI in combination with copper thiophene-2-carboxylate (CuTC) as promotor and tetra-n-butylammonium diphenylphosphinate as an effective tin scavenger; in some cases, it proved beneficial to further supplement the mixture with catalytic amounts of Pd(PPh3)4. Under these conditions, the reaction is robust, high yielding, and compatible with many functional groups that might not subsist under more traditional conditions used to C-alkylate organotin derivatives. A qualitative analysis of the reaction profile suggested that the in situ formation of a reactive organocopper intermediate and its interception by MeI is only barely faster than O-methylation of the phosphinate additive by the same alkylating agent. To guarantee high yields and prevent net protodestannation from occurring, the reaction protocol had to be optimized such that these competing processes are properly decoupled. The new method is particularly well suited for the stereoselective preparation of the (E)-2-methylbut-2-en-1-ol motif that is present in numerous natural products. Alternatively, this particular target structure can be accessed starting from α-hydroxy alkenylsiloxane precursors, which get C-methylated upon exposure to CuI/LiOtBu and MeI by what is thought to be a Brook rearrangement/ alkylation sequence. The required substrates are best prepared by ruthenium-catalyzed trans-hydrosilylation or trans-hydrostannation of propargyl alcohols

    Toward the Total Synthesis of Spirastrellolide A. Part 2: Conquest of the Northern Hemisphere

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    North and South: The unique biological activity of the natural product spirastrellolide A renders it an attractive lead for anticancer agents. The southern hemisphere (C1–C25) and the northern hemisphere (including the chlorinated [5,6,6]-bis-spiroacetal entity and the lateral C42–C47 chain) are prepared by concise and efficient routes. Consequently, the entire carbon framework of this potent phosphatase inhibitor, which contains 21 chiral centers, is prepared in an optically active form, and an important step toward structure determination by total synthesis is achieved

    Analysis of gene expression to predict dynamics of future hypertension incidence in type 2 diabetic patients

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    BACKGROUND: The main focus of the Genetic Analysis Workshop 19 (GAW19) is identification of genes related to the occurrence of hypertension in the cohort of patients with type 2 diabetes mellitus (T2DM). The aim of our study was to predict dynamics of the future hypertension incidence, based on gene expression profiles, systolic and diastolic blood pressure changes in time, sex, baseline age, and cigarette smoking status. We analyzed data made available to GAW19 participants, which included gene expression profiles of peripheral blood mononuclear cells (PBMCs) from the diabetic members of 20 Mexican American families. METHODS: On the basis of mid blood pressure measurements at several time points, the coefficient of regression (slope) was calculated for each individual. We corrected the slope value in patients treated with antihypertensive medications. Feature preprocessing methods were used to remove highly correlated probes and linear dependencies between them. Subsequently, multiple linear regression model was used to associate gene expression with the regression coefficient calculated for each T2DM patient. Tenfold cross-validation was used to validate the model. We used linear mixed effects model and kinship coefficients to account for the family structure. All calculations were performed in R. RESULTS: This analysis allowed us to identify 6 well-annotated genes: RTP4, FXYD6, GDF11, IFNAR1, NOX3, and HLA-DQ2, associated with dynamics of future hypertension incidence. Two of them, IFNAR1 and NOX3 were previously implicated in pathogenesis of hypertension. CONCLUSIONS: There is no obvious mechanism that links all detected genes with dynamics of hypertension incidence. Identification of possible connection with hypertension needs further investigation

    Toward the Total Synthesis of Spirastrellolide A. Part 1: Strategic Considerations and Preparation of the Southern Domain

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    North and South: The unique biological activity of the natural product spirastrellolide A renders it an attractive lead for anticancer agents. The southern hemisphere (C1–C25) and the northern hemisphere (including the chlorinated [5,6,6]-bis-spiroacetal entity and the lateral C42–C47 chain) are prepared by concise and efficient routes. Consequently, the entire carbon framework of this potent phosphatase inhibitor, which contains 21 chiral centers, is prepared in an optically active form, and an important step toward structure determination by total synthesis is achieved
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