1,053 research outputs found

    Limitations of Online Information on Abdominal Aortic Aneurysm

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    Background. Patients with AAA face a complex decision, and knowledge of the risks and benefits of each treatment option is essential to informed decision-making. Here we assess the current information on the internet accessible to patients regarding the management of AAA. Study Design. We performed a search on Google using the keywords “abdominal aortic aneurysm” and reviewed the top 50 web sites. We focused on information related to treatment options and alternatives to treatment and the risks of each option. Results. Twenty-seven websites were included in the study. Nearly 30% of websites discussed the risk of mortality and myocardial infarction after open surgery, compared to only 7.4% for both risks after EVAR. Other complications were listed by fewer websites. Fifty-five percent of websites reported that patients had a faster recovery following EVAR, but only 18.5% mentioned the risk of reintervention after EVAR or the need for long-term surveillance with CT scans. Conclusions. While most websites included descriptive information on AAA and mentioned the potential treatment options available to patients, the discussion of the risks of open surgery and EVAR was inadequate. These results suggest that websites frequently accessed by patients lack important information regarding surgical risk

    Locating Discretionary Service Facilities II: Maximizing Market Size, Minimizing Inconvenience

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    Revised November 1992Discretionary service facilities are providers of products and/or services that are purchased by customers who are traveling on otherwise pre-planned trips such as the daily commute. Optimum location of such facilities requires them to be at or near points in the transportation network having sizable flows of different potential customers. In [1] a first version of this problem was formulated, assuming that customers would make no deviations, no matter how small, from the pre-planned route to visit a discretionary service facility. Here the model is generalized in a number of directions, all sharing the property that the customer may deviate from the pre-planned route to visit a discretionary service facility. Three different generalizations are offered, two of which can be solved approximately by greedy heuristics and the third by any approximate or exact method used to solve the pmedian problem. It is shown for those formulations yielding to a greedy heuristic approximate solution, including the formulation in [1], that the problems are examples of optimizing submodular functions for which the Nemhauser et. al. [51 bound on the performance of a greedy algorithm holds. In particular, the greedy solution is always within 37% of optimal, and for one of the formulations it is proved that the bound is tight

    Self-interaction chromatography as a tool for optimizing conditions for membrane protein crystallization

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    The second virial coefficient, or B value, is a measurement of how well a protein interacts with itself in solution. These interactions can lead to protein crystallization or precipitation, depending on their strength, with a narrow range of B values (the `crystallization slot') being known to promote crystallization. A convenient method of determining the B value is by self-interaction chromatography. This paper describes how the light-harvesting complex 1-reaction centre core complex from Allochromatium vinosum yielded single straight-edged crystals after iterative cycles of self-interaction chromatography and crystallization. This process allowed the rapid screening of small molecules and detergents as crystallization additives. Here, a description is given of how self-interaction chromatography has been utilized to improve the crystallization conditions of a membrane protein

    Promoting Positive Youth Development The Miami Youth Development Project (YDP)

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    The Miami Youth Development Project (YDP) had its beginnings in the early 1990s as a grassroots response to the needs of troubled (multiproblem) young people in the community (Arnett, Kurtines, & Montgomery, 2008, this issue). YDP is an important outcome of efforts to create positive youth development interventions that draw on the strengths of developmental intervention science outreach research in the development of community-supported positive development programs (i.e., an approach that focuses on meeting community needs as well as youth needs by generating innovative knowledge of evidence-based change intervention strategies that are feasible, affordable, and sustainable in “real world” settings, (Kurtines, Ferrer-Wreder, Cass Lorente, Silverman, Montgomery, 2008, this issue). Now completing its second decade, YDP represents an effort to bring together a more empowering model of knowledge development for research involvement in the community, a nuanced and contextualized notion of youth and their development, and methodologies that richly reflect rather than reduce the experiences of the young people whose development the authors seek to promote

    Promoting Positive Identity Development in Troubled Youth: A Developmental Intervention Science Outreach Research Approach

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    This article illustrates how developmental intervention science outreach research contributes to knowledge development on the promotion of positive identity development by describing results from the Miami Youth Development Project. The project is committed to the use of descriptive and explanatory knowledge about evidence-based individual and institutional intervention strategies for promoting developmental change in self and identity. Our efforts, described here, include a method for measuring theoretically and personally meaningful identity change, a procedure for integrating key aspects of qualitative and quantitative data through relational data analysis, and an evidence-based positive youth development intervention that fosters measurable and meaningful identity change

    Acoustic Analog to Quantum Mechanical Level Splitting

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    A simple physical system is discussed that mirrors the quantum mechanical infinite square well with a central delta well potential. The physical realization consists of a continuous sound wave traveling in a pair of tubes separated by an adjustable diaphragm. The equivalence between the quantum system and the acoustic system is explored. The analytic solution to the quantum system exhibits level splitting as does the acoustic system

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    Increased shedding of HU177 correlates with worse prognosis in primary melanoma

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    <p>Abstract</p> <p>Background</p> <p>Increased levels of cryptic collagen epitope HU177 in the sera of melanoma patients have been shown to be associated with thicker primary melanomas and with the nodular histologic subtype. In this study, we investigate the association between HU177 shedding in the sera and clinical outcome in terms of disease-free survival (DFS) and overall survival (OS).</p> <p>Methods</p> <p>Serum samples from 209 patients with primary melanoma prospectively enrolled in the Interdisciplinary Melanoma Cooperative Group at the New York University Langone Medical Center (mean age = 58, mean thickness = 2.09 mm, stage I = 136, stage II = 41, stage III = 32, median follow-up = 54.9 months) were analyzed for HU177 concentration using a validated ELISA assay. HU177 serum levels at the time of diagnosis were used to divide the study cohort into two groups: low and high HU177. DFS and OS were estimated by Kaplan-Meier survival analysis, and the log-rank test was used to compare DFS and OS between the two HU177 groups. Multivariate Cox proportional hazards regression models were employed to examine the independent effect of HU177 category on DFS and OS.</p> <p>Results</p> <p>HU177 sera concentrations ranged from 0-139.8 ng/ml (mean and median of 6.2 ng/ml and 3.7 ng/ml, respectively). Thirty-eight of the 209 (18%) patients developed recurrences, and 34 of the 209 (16%) patients died during follow-up. Higher HU177 serum level was associated with an increased rate of melanoma recurrence (p = 0.04) and with increasing mortality (p = 0.01). The association with overall survival remained statistically significant after controlling for thickness and histologic subtype in a multivariate model (p = 0.035).</p> <p>Conclusions</p> <p>Increased shedding of HU177 in the serum of primary melanoma patients is associated with poor prognosis. Further studies are warranted to determine the clinical utility of HU177 in risk stratification compared to the current standard of care.</p

    The Structure of Amorphous and Deeply Supercooled Liquid Alumina

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    Liquid Al2O3 has been supercooled more than 500 K below its melting point (Tm = 2,327 K) using aerodynamic levitation and laser heating techniques. High energy synchrotron x-ray measurements were performed over a temperature range of 1,817 ≤ T (K) ≤ 2,700 and stroboscopic neutron diffraction at 1,984 and 2,587 K. The diffraction patterns have been fitted with Empirical Potential Structure Refinement (EPSR) models and compared to classical Molecular Dynamics (MD) simulation results. Both sets of models show similar trends, indicating the presence of high populations of AlO4 and AlO5 polyhedral units predominantly linked by triply shared oxygen atoms. EPSR reveals that the mean Al–O coordination number changes linearly with temperature with nAlO = 4.41 – [1.25 × 10−4] (T – Tm), with a 2.5 Å cutoff. Both EPSR and MD simulations reveal a direction of the temperature dependence of the aluminate network structure which moves further away from the glass forming ideal (nAlO = 3) during supercooling. Furthermore, we provide new experimental data and models for amorphous alumina grown by sequential infiltration synthesis of a polymer template. The amorphous solid form likely has a larger Al-O coordination number than the liquid, consistent with expectations for the hypothetical glass
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