310 research outputs found

    Strain in GaAs by low-dose ion implantation

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    The production of strain in (100) GaAs by low-dose ion implantation has been investigated. Implantations were conducted at room temperature with ions of He, B, C, Ne, Si, P, and Te. Energies were between 100 and 500 keV, and each species was implanted over a range of doses sufficient to create perpendicular strain below 0.3%. The perpendicular strains epsilon [perpendicular] were measured by x-ray double-crystal diffractometry about the (400) Bragg condition. Detailed depth profiles of epsilon[perpendicular] were obtained by fitting the resulting rocking curves with a kinematic model for the diffraction. For all implantations the maximum in the epsilon[perpendicular] distribution was found approximately from the separation of the lowest-angle prominent oscillation from the substrate peak. The depth profiles of perpendicular strain had the same shape as the calculated profiles of energy deposited per ion by nuclear collisions, FD. The maximum perpendicular strains scaled linearly with the dose phi of the implanted ions for all ion species. Also the ratio of maximum strain to dose was found to vary linearly with FD over more than 2 orders of magnitude in FD. We therefore conclude that epsilon[perpendicular]=KphiFD at all depths, where K is a constant. The value of K was found to be (5±1)×10^−2 Å^3/eV. Our results suggest that this holds for any ion species in the mass range 4–128 amu, with energy in the hundreds of keV, implanted into (100) GaAs at room temperature, provided the maximum strain is less than 0.3%

    Identification and cost of adverse events in metastatic breast cancer in taxane and capecitabine based regimens.

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    PurposeWe sought to compare the economic impact of treatment-related adverse events (AEs) in patients with metastatic breast cancer (mBC) using taxane- or capecitabine-based treatment regimens as either first- or second-line (FL or SL) therapy in the US.MethodsWe used healthcare claims data from the Truven Health Analytics MarketScan® Commercial Databases to conduct a retrospective cohort study comparing the economic impact of AEs amongst taxane- and capecitabine-treated mBC patients in the US. We selected women diagnosed with mBC between 2008-2010 who received a taxane or capecitabine as first- or second-line (FL or SL) chemotherapy. Costs related to hospitalization, outpatient services, emergency department visits, chemotherapy and other medications were tabulated and combined to determine total healthcare costs. The incremental monthly costs associated with the presence of AEs compared to no AEs were estimated using generalized linear models, controlling for age and Charlson Comorbidity Index.ResultsWe identified 15,443 mBC patients meeting inclusion criteria. Adjusted total monthly costs were significantly higher in those who experienced AEs than in those without AEs in both lines of treatment (FL incremental cost: taxanes 1,142,capecitabine1,142, capecitabine 1,817; SL incremental cost: taxanes 1,448,capecitabine1,448, capecitabine 4,437). Total costs increased with the number of AEs and were primarily driven by increased hospitalization amongst those with AEs.ConclusionsAdverse events in taxane- or capecitabine-treated mBC patients are associated with significant increases in costs. Selecting treatment options associated with fewer AEs may reduce costs and improve outcomes in these patients

    Treatment patterns and clinical outcomes for patients with de novo versus recurrent HER2-positive metastatic breast cancer

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    Improvements in screening and adjuvant therapy for breast cancer are associated with decreased recurrence, which may have the effect of increasing the proportion of patients presenting with first-line de novo versus recurrent metastatic breast cancer (MBC). Here, we describe and compare patients with de novo versus recurrent human epidermal growth factor 2 (HER2)-positive MBC. registHER was a prospective observational cohort study (late 2003–early 2006) of 1,023 patients with HER2-positive MBC. Baseline characteristics, treatment patterns, and clinical outcomes were examined in patients with newly diagnosed de novo (n = 327) compared with recurrent HER2-positive MBC after prior treatment for early-stage disease (n = 674). Patients with de novo HER2-positive MBC were less likely to have lung metastases, more likely to have lymph node, bone, and/or liver metastases and >4 sites of metastases and more likely to receive combined or concurrent chemotherapy and hormonal therapy with or without trastuzumab than those with recurrent HER2-positive MBC. Median follow-up was 29 months. Median progression-free survival was 12.1 versus 9.3 months [hazard ratio = 0.716 (95 % confidence interval (CI) 0.617–0.831)], and overall survival was 41.7 versus 32.8 months [hazard ratio = 0.766 (95 % CI 0.633–0.928)] for patients with de novo versus recurrent HER2-positive MBC, respectively. Patients with recurrent HER2-positive MBC had similar outcomes regardless of whether they received prior adjuvant therapy, excluding hormonal therapy. Despite presenting with more advanced-stage disease and higher tumor burdens, patients with de novo HER2-positive MBC have more favorable clinical outcomes than those with recurrent HER2-positive MBC. These differences may be due to effects of prior drug exposure and could have implications for designing and interpreting clinical trials

    Do residents’ perceptions of being well-placed and objective presence of local amenities match? A case study in West Central Scotland, UK

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    Background:<p></p> Recently there has been growing interest in how neighbourhood features, such as the provision of local facilities and amenities, influence residents’ health and well-being. Prior research has measured amenity provision through subjective measures (surveying residents’ perceptions) or objective (GIS mapping of distance) methods. The latter may provide a more accurate measure of physical access, but residents may not use local amenities if they do not perceive them as ‘local’. We believe both subjective and objective measures should be explored, and use West Central Scotland data to investigate correspondence between residents’ subjective assessments of how well-placed they are for everyday amenities (food stores, primary and secondary schools, libraries, pharmacies, public recreation), and objective GIS-modelled measures, and examine correspondence by various sub-groups.<p></p> Methods:<p></p> ArcMap was used to map the postal locations of ‘Transport, Health and Well-being 2010 Study’ respondents (n = 1760), and the six amenities, and the presence/absence of each of them within various straight-line and network buffers around respondents’ homes was recorded. SPSS was used to investigate whether objective presence of an amenity within a specified buffer was perceived by a respondent as being well-placed for that amenity. Kappa statistics were used to test agreement between measures for all respondents, and by sex, age, social class, area deprivation, car ownership, dog ownership, walking in the local area, and years lived in current home.<p></p> Results:<p></p> In general, there was poor agreement (Kappa <0.20) between perceptions of being well-placed for each facility and objective presence, within 800 m and 1000 m straight-line and network buffers, with the exception of pharmacies (at 1000 m straight-line) (Kappa: 0.21). Results varied between respondent sub-groups, with some showing better agreement than others. Amongst sub-groups, at 800 m straight-line buffers, the highest correspondence between subjective and objective measures was for pharmacies and primary schools, and at 1000 m, for pharmacies, primary schools and libraries. For road network buffers under 1000 m, agreement was generally poor.<p></p> Conclusion:<p></p> Respondents did not necessarily regard themselves as well-placed for specific amenities when these amenities were present within specified boundaries around their homes, with some exceptions; the picture is not clear-cut with varying findings between different amenities, buffers, and sub-groups

    Antiangiogenic therapy for breast cancer

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    Angiogenesis is an important component of cancer growth, invasion and metastasis. Therefore, inhibition of angiogenesis is an attractive strategy for treatment of cancer. We describe existing clinical trials of antiangiogenic agents and the challenges facing the clinical development and optimal use of these agents for the treatment of breast cancer. Currently, the most promising approach has been the use of bevacizumab, a humanized monoclonal antibody directed against the most potent pro-angiogenic factor, vascular endothelial growth factor (VEGF). Small molecular inhibitors of VEGF tyrosine kinase activity, such as sorafenib, appear promising. While, the role of sunitinib and inhibitors of mammalian target of rapamycin (mTOR) in breast cancer has to be defined. Several unanswered questions remain, such as choice of drug(s), optimal duration of therapy and patient selection criteria

    Normal growth and development in mice over-expressing the CCN family member WISP3

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    Loss-of-function mutations in the gene WISP3 cause the autosomal recessive human skeletal disease Progressive Pseudorheumatoid Dysplasia, whereas mice with knockout mutations of Wisp3 have no phenotype. The lack of a phenotype in the Wisp3 knockout mice has constrained studies of the protein’s in vivo function. Over-expression experiments in zebrafish indicated that WISP3 may function as a BMP and Wnt signaling modulator. To determine whether these biologic activities are retained in mice, we created two strains of transgenic mice that over-express WISP3 in a broad array of tissues. Despite strong and persistent protein over-expression, the transgenic mice remained phenotypically indistinguishable from their non-transgenic littermates. Surprisingly, WISP3 contained in conditioned medium recovered from transgenic mouse primary kidney cell cultures was able to bind BMP and to inhibit BMP signaling in vitro. Factors that account for the difference between the in vitro and in vivo activities of WISP3 remain unknown. At present, the mouse remains a challenging model organism in which to explore the biologic function of WISP3

    Measurement Properties of Questionnaires Assessing Complementary and Alternative Medicine Use in Pediatrics: A Systematic Review

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    Complementary and alternative medicine (CAM) is commonly used by children, but estimates of that use vary widely partly due to the range of questionnaires used to assess CAM use. However, no studies have attempted to appraise measurement properties of these questionnaires. The aim of this systematic review was to critically appraise and summarize measurement properties of questionnaires of CAM use in pediatrics.A search strategy was implemented in major electronic databases in March 2011 and conference websites, scientific journals and experts were consulted. Studies were included if they mentioned a questionnaire assessing the prevalence of CAM use in pediatrics. Members of the team independently rated the methodological quality of the studies (using the COSMIN checklist) and measurement properties of the questionnaires (using the Terwee and Cohen criteria).A total of 96 CAM questionnaires were found in 104 publications. The COSMIN checklist showed that no studies reported adequate methodological quality. The Terwee criteria showed that all included CAM questionnaires had indeterminate measurement properties. According to the Cohen score, none were considered to be a well-established assessment, two approached the level of a well-established assessment, seven were promising assessments and the remainder (n = 87) did not reach the score's minimum standards.None of the identified CAM questionnaires have been thoroughly validated. This systematic review highlights the need for proper validation of CAM questionnaires in pediatrics, which may in turn lead to improved research and knowledge translation about CAM in clinical practice
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