478 research outputs found

    Underuse and Overuse of Colonoscopy for Repeat Screening and Surveillance in the Veterans Health Administration

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    Regular screening with colonoscopy lowers colorectal cancer incidence and mortality. We aimed to determine patterns of repeat and surveillance colonoscopy and identify factors associated with over- and underuse of colonoscopy

    Ce(OH)2Cl and lanthanide-substituted variants as precursors to redox-active CeO2 materials

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    The cerium(III) hydroxide chloride Ce(OH)2Cl crystallises directly as a polycrystalline powder from a solution of CeCl3·7H2O in poly(ethylene) glycol (Mn = 400) heated at 240 °C and is found to be isostructural with La(OH)2Cl, as determined from high-resolution synchrotron powder X-ray diffraction (P21/m, a = 6.2868(2) Å, b = 3.94950(3) Å, c = 6.8740(3) Å, β = 113.5120(5)°). Replacement of a proportion of the cerium chloride in synthesis by a second lanthanide chloride yields a set of materials Ce1−xLnx(OH)2Cl for Ln = La, Pr, Gd, Tb. For La the maximum value of x is 0.2, with an isotropic expansion of the unit cell, but for the other lanthanides a wider composition range is possible, and the lattice parameters show an isotropic contraction with increasing x. Thermal decomposition of the hydroxide chlorides at 700 °C yields mixed-oxides Ce1−xLnxO2−δ that all have cubic fluorite structures with either expanded (Ln = La, Gd) or contracted (Ln = Pr, Tb) unit cells compared to CeO2. Scanning electron microscopy shows a shape memory effect in crystal morphology upon decomposition, with clusters of anisotropic sub-micron crystallites being seen in the precursor and oxide products. The Pr- and Tb-substituted oxides contain the substituent in a mixture of +3 and +4 oxidation states, as seen by X-ray absorption near edge structure spectroscopy at the lanthanide LIII edges. The mixed oxide materials are examined using temperature programmed reduction in 10%H2 in N2, which reveals redox properties suitable for heterogeneous catalysis, with the Pr-substituted materials showing the greatest reducibility at lower temperature

    Reviews

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    Tolkien, Race and Cultural History: From Fairies to Hobbits. Dimitra Fimi. Reviewed by Jason Fisher. Charles Williams and his Contemporaries. Suzanne Bray and Richard Sturch, eds. Reviewed by Joe R. Christopher. In the Land of Invented Languages: Esperanto Rock Stars, Klingon Poets, Loglan Lovers, and the Mad Dreamers who Tried to Build a Perfect Language. Arika Okrent. Reviewed by Harley J. Sims. Millennial Mythmaking: Essays on the Power of Science Fiction and Fantasy Literature, Films and Games. John Perlich & David Whitt, eds. Reviewed by Priscilla Hobbs Middle-earth Minstrel: Essays on Music in Tolkien. Bradford Lee Eden, ed. Reviewed by Emily A. Moniz. Harry Potter & Imagination: The Way Between Two Worlds. Travis Prinzi. Reviewed by David D. Oberhelman. Fastitocalon: Studies in Fantasticism Ancient to Modern: Immortals and the Undead. Eds. Thomas Honneger and Fanfan Chen. Reviewed by Janet Brennan Croft. Theodor Seuss Geisel [sic]. Donald E. Pease. Reviewed by Joe R. Christopher

    A theory-based approach to understanding condom errors and problems reported by men attending an STI clinic

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    The official published version can be accessed from the link below - Copyright @ 2008 Springer VerlagWe employed the information–motivation–behavioral skills (IMB) model to guide an investigation of correlates for correct condom use among 278 adult (18–35 years old) male clients attending a sexually transmitted infection (STI) clinic. An anonymous questionnaire aided by a CD-recording of the questions was administered. Linear Structural Relations Program was used to conduct path analyses of the hypothesized IMB model. Parameter estimates showed that while information did not directly affect behavioral skills, it did have a direct (negative) effect on condom use errors. Motivation had a significant direct (positive) effect on behavioral skills and a significant indirect (positive) effect on condom use errors through behavioral skills. Behavioral skills had a direct (negative) effect on condom use errors. Among men attending a public STI clinic, these findings suggest brief, clinic-based, safer sex programs for men who have sex with women should incorporate activities to convey correct condom use information, instill motivation to use condoms correctly, and directly enhance men’s behavioral skills for correct use of condoms

    Circulating tumor DNA predicts survival in patients with resected high risk stage II/III melanoma

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    Background: Patients with high-risk stage II/III resected melanoma commonly develop distant metastases. At present, we cannot differentiate between patients who will recur or those who are cured by surgery. We investigated if circulating tumor DNA (ctDNA) can predict relapse and survival in patients with resected melanoma. Patients and methods: We carried out droplet digital polymerase chain reaction to detect BRAF and NRAS mutations in plasma taken after surgery from 161 stage II/III high-risk melanoma patients enrolled in the AVAST-M adjuvant trial. Results: Mutant BRAF or NRAS ctDNA was detected (≥1 copy of mutant ctDNA) in 15/132 (11%) BRAF mutant patient samples and 4/29 (14%) NRAS mutant patient samples. Patients with detectable ctDNA had a decreased disease-free interval [DFI; hazard ratio (HR) 3.12; 95% confidence interval (CI) 1.79–5.47; P < 0.0001] and distant metastasis-free interval (DMFI; HR 3.22; 95% CI 1.80–5.79; P < 0.0001) versus those with undetectable ctDNA. Detectable ctDNA remained a significant predictor after adjustment for performance status and disease stage (DFI: HR 3.26, 95% CI 1.83–5.83, P < 0.0001; DMFI: HR 3.45, 95% CI 1.88–6.34, P < 0.0001). Five-year overall survival rate for patients with detectable ctDNA was 33% (95% CI 14%–55%) versus 65% (95% CI 56%–72%) for those with undetectable ctDNA. Overall survival was significantly worse for patients with detectable ctDNA (HR 2.63; 95% CI 1.40–4.96); P = 0.003) and remained significant after adjustment for performance status (HR 2.50, 95% CI 1.32–4.74, P = 0.005). Conclusion: ctDNA predicts for relapse and survival in high-risk resected melanoma and could aid selection of patients for adjuvant therapy

    Conservationists’ perspectives on poverty: an empirical study

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    1. Biodiversity conservation interventions have long confronted challenges of human poverty. The ethical foundations of international conservation, including conservation’s relationship with poverty, are currently being interrogated in animated debates about the future of conservation. However, while some commentary exists, empirical analysis of conservation practitioner perspectives on poverty, and their ethical justification, has been lacking thus far. 2. We used Q methodology complemented by more detailed qualitative analysis to examine empirically perspectives on poverty and conservation within the conservation movement, and compare these empirical discourses to positions within the literature. We sampled conservation practitioners in western headquartered organisations, and in Bolivia, China, Nepal and Uganda, thereby giving indications of these perspectives in Latin America, Asia and Africa. 3. While there are some elements of consensus, for instance the principle that the poor should not shoulder the costs of conserving a global public good, the three discourses elicited diverge in a number of ways. Anthropocentrism and ecocentrism differentiate the perspectives, but beyond this, there are two distinct framings of poverty which conservation practitioners variously adhere to. 4. The first prioritises welfare, needs and sufficientarianism, and is more strongly associated with the China, Nepal and Uganda case studies. The second framing of poverty focuses much more on the need for ‘do no harm’ principles and safeguards, and follows an internationalised human rights-oriented discourse. 5. There are also important distinctions between discourses about whether poverty is characterised as a driver of degradation, or more emphasis is placed on overconsumption and affluence in perpetuating conservation threats. This dimension particularly illuminates shifts in thinking in the 30 or so years since the Brundtland report, and reflecting new global realities. 6. This analysis serves to update, parse and clarify differing perspectives on poverty within the conservation, and broader environmental movement, in order to illuminate consensual aspects between perspectives, and reveal where critical differences remain
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