1,032 research outputs found

    Molecular-dynamics simulations of nickel clusters

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    Structural stability and energetics of nickel clusters, Nih (N = 3 - 459), have been inves tigated by molecular-dynamics simulations, A size-dependent empirical model potential energy function has been used in the simulations. Stable structures of the microclusters with sizes N = 3 - 55 and clusters generated from fee crystal structure with sizes N = 79 - 459 have been determined by molecular-dynamics simulations. It has been found that the fivefold symmetry appears on the surface of the spherical clusters. The average coordination number shows a size-dependent characteristic, on the other hand the average nearest-neighbor distance does not show a size-dependence

    Spectral Properties of Fourth Order Differential Operators with Periodic and Antiperiodic Boundary Conditions

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    In this paper, we consider the following periodic and antiperiodic problem yiv + p2 (x) y + p1 (x) y + p0 (x) y = λy, 0 <x< 1, y(s) (1) − (−1)σ y(s) (0) = 0, s = 0, 3, where λ is a spectral parameter; pj (x) ∈ L1(0, 1), j = 0, 1, p2(x) ∈ W1 1 (0, 1) with 1 0 p2(Ο)dΟ = 0 are complex-valued functions and σ = 0, 1. The boundary conditions of this problem are periodic-antiperiodic boundary conditions and it is well known that they are regular but not strongly regular. Asymptotic formulae for eigenvalues and eigenfunctions of the considered boundary value problem are established. Under the condition (p2 (1) − p2 (0) − 2c1) (p2 (1) − p2 (0) + 2c1) = 0, it is proved that all the eigenvalues (except for finite number) are simple, where c1 = 1 0 p1(Ο)dΟ. Furthermore, we prove that the system of root functions of this spectral problem forms a basis in the space Lp(0, 1), 1 <p< ∞, when p1(1) = p1(0); p(s) 2 (1) = p(s) 2 (0), s = 0, 1; pj (x) ∈ Wj 1 (0, 1), j = 0, 1, 2; c1 = 0. Also, it is shown that this basis is unconditional for p = 2

    Matching patient and physician preferences in designing a primary care facility network

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    Cataloged from PDF version of article.This paper introduces an integer programming model for planning primary care facility networks, which accounts for the interests of different stakeholders while maximizing access to health care. Physician allocation to health-care facilities is explicitly modelled, which allows consideration of physician incentives in the planning phase. An illustrative case study in the Turkish primary care system is presented to show the implications of focusing on patient or physician preferences in the planning phase. A discussion of trade-offs between the different stakeholder preferences and some recommendations for modelling choices to match these preferences are provided. In the context of this case, we found that using an access measure that decays with distance, and incorporating nearest allocation constraints improves performance for all stakeholders. We also show that increasing the number of physicians may have adverse affects on access measures when physician preferences are addressed

    Evaluation of vertebral artery dominance, hypoplasia and variations in the origin: angiographic study in 254 patients

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    Background: The aim of this study was to determine the dimensional characteristics and variations in the origin of vertebral arteries (VA). Materials and methods: We retrospectively reviewed angiographic studies in 254 patients (133 males, 121 females) for the evaluation of diameter differences in VA. We examined different criteria from the literature (difference of ≄ 0.3 mm, ≄ 0.8 mm, ≄ 1 mm between the widths of two VA and diameter ratio more than 1.4) to find out the dominant VA, rate of co-dominance and hypoplasia. The differences among groups were analysed using the c2 and Kruskal-Wallis test. Also concordance analysis test was used to determine correspondence between the tests. We also noticed the variations in the origin of VA. Results: The average diameter of VA in 254 patients was 3.21 ± 0.7 mm on the right, and 3.16 ± 0.7 mm on the left. The average diameter difference was found 0.88 ± 0.7 mm. The rate of hypoplasia was found 7.1% on the right and 9.4% on the left. Among 254 patients according to the criterion of any diameter difference; right side was found wider in 126 (49.6%) patients and left side was found wider in 120 (47.2%) patients. The criterion of 0.3 mm or greater difference showed right VA dominance in 107 (42.1%) patients, left VA dominance in 99 (39%) patients. Co-dominance was mainly observed when we used the criteria of 0.8 mm and 1 mm or greater difference and diameter ratio more than 1.4. We found out harmony of two criterion of difference of ≄ 0.8 mm and ≄ 1 mm (concordance analysis test, 76.1%). There was no statistically significant relation between age, gender and any dominance criteria (p &gt; 0.05). The majority of VA showed classical origin arising from both subclavian arteries with a rate of 94.9%. Conclusions: The most striking result we have found is the dominance of the right VA in diameter by using all different criteria unlike with previous reports in the literature.

    Promoter methylation analysis of CDH1 and p14ARF genes in patients with urothelial bladder cancer

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    BACKGROUND/AIM: Urothelial bladder cancer arises from the accumulation of multiple epigenetic and genetic changes. We aimed to investigate the specificity and sensitivity of gene-specific promoter methylation of CDH1 and p14ARF genes in the early diagnosis of bladder cancer and compare those with other diagnostic tests in our population. PATIENTS AND METHODS: In the current study, 65 patients with urothelial bladder cancer and 35 controls without any history of cancer were recruited. Methylation profiles of CDH1 and p14ARF genes from tumor and urine samples were determined by methylation-specific polymerase chain reaction method. RESULTS: Methylation of CDH1 and p14ARF genes in tumor samples was 95.4% and 78.5%, respectively. The methylation frequencies were found to be 68.8% for CDH1 gene and 72.9% for p14ARF gene in urine samples. Sensitivities of CDH1, p14ARF and urine cytology were found to be 67.4%, 72.1% and 34.9%, respectively, while their specificities were 93.9%, 63.6% and 93.9%, respectively. CONCLUSION: Aberrant promoter methylation of CDH1 and p14ARF genes can be used to detect urothelial bladder cancer. In low-grade tumors, when compared with urine cytology, combined methylation analysis of CDH1 and p14ARF genes may not increase the sensitivity to identify malignant cells in urine samples

    A new multi-modal dataset for human affect analysis

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    In this paper we present a new multi-modal dataset of spontaneous three way human interactions. Participants were recorded in an unconstrained environment at various locations during a sequence of debates in a video conference, Skype style arrangement. An additional depth modality was introduced, which permitted the capture of 3D information in addition to the video and audio signals. The dataset consists of 16 participants and is subdivided into 6 unique sections. The dataset was manually annotated on a continuously scale across 5 different affective dimensions including arousal, valence, agreement, content and interest. The annotation was performed by three human annotators with the ensemble average calculated for use in the dataset. The corpus enables the analysis of human affect during conversations in a real life scenario. We first briefly reviewed the existing affect dataset and the methodologies related to affect dataset construction, then we detailed how our unique dataset was constructed

    Copula-based multivariate input modeling

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    In this survey, we review the copula-based input models that are well suited to provide multivariate input-modeling support for stochastic simulations with dependent inputs. Specifically, we consider the situation in which the dependence between pairs of simulation input random variables is measured by tail dependence (i.e., the amount of dependence in the tails of a bivariate distribution) and review the techniques to construct copula-based input models representing positive tail dependencies. We complement the review with the parameter estimation from multivariate input data and the random-vector generation from the estimated input model with the purpose of driving the simulation. © 2012 Elsevier Ltd

    Crystal structure of a lipoxygenase in complex with substrate: The arachidonic acid-binding site of 8R-lipoxygenase

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    Lipoxygenases (LOX) play critical roles in mammalian biology in the generation of potent lipid mediators of the inflammatory response; consequently, they are targets for the development of isoform-specific inhibitors. The regio- and stereo-specificity of the oxygenation of polyunsaturated fatty acids by the enzymes is understood in terms of the chemistry, but structural observation of the enzyme-substrate interactions is lacking. Although several LOX crystal structures are available, heretofore the rapid oxygenation of bound substrate has precluded capture of the enzyme-substrate complex, leaving a gap between chemical and structural insights. In this report, we describe the 2.0 Å resolution structure of 8R-LOX in complex with arachidonic acid obtained under anaerobic conditions. Subtle rearrangements, primarily in the side chains of three amino acids, allow binding of arachidonic acid in a catalytically competent conformation. Accompanying experimental work supports a model in which both substrate tethering and cavity depth contribute to positioning the appropriate carbon at the catalytic machinery

    Two-year long safety and efficacy of deferasirox film-coated tablets in patients with thalassemia or lower/intermediate risk MDS: phase 3 results from a subset of patients previously treated with deferasirox in the ECLIPSE study

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    Background: Despite the proven benefits of iron chelation therapy (ICT) in the management of chronic iron overload and related complications, compliance to long-term ICT is challenging. Results from the ECLIPSE study, an open-label, randomized, multicenter, 2-arm, phase 2 study evaluated the safety of deferasirox dispersible tablet and film-coated tablet (FCT) formulations in patients with transfusion-dependent thalassemia (TDT) or very low, low, or intermediate risk myelodysplastic syndrome (MDS) treated over 24 weeks. Methods: The aim of the current study (a 2-year, open-label, multicenter, single-arm, phase 3 study) is to evaluate the long-term safety and efficacy of deferasirox FCT in a subset of patients with TDT or lower/intermediate-risk MDS treated for 2 years after the completion of 24 weeks of treatment with deferasirox in the ECLIPSE phase 2 study. Results: Of 53 patients enrolled, 34 (64.2%) completed treatment and study. Adverse events (AEs) reported in most patients (similar to 70%) were of mild to moderate severity. Headache and diarrhea were the most frequently (&gt; 25%) reported AEs. None of the serious AEs (including 1 death) were considered treatment related. No new safety signal was identified, and long-term safety of deferasirox FCT was consistent with the known safety profile of deferasirox. No major concerns associated with gastrointestinal tolerability, renal safety, or hematological abnormalities (thrombocytopenia/neutropenia) were reported during the 2 years. Patients receiving deferasirox FCT had a treatment compliance (by pill count) of similar to 90% and persistence (continuous use for &gt;= 30 days) of &gt; 95%. Reduction in serum ferritin level was almost consistent starting from week 2 across all post-baseline time points (relative reduction: month 6, 19%; month 12, 29%). Conclusions: The results from this 2-year interventional study suggest that the recommended dosing of deferasirox FCT, with better tolerability, palatability, and compliance, offers a favorable option of ICT for long-term management of iron overload and associated complications in TDT

    The analysis of facial beauty: an emerging area of research in pattern analysis

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    Much research presented recently supports the idea that the human perception of attractiveness is data-driven and largely irrespective of the perceiver. This suggests using pattern analysis techniques for beauty analysis. Several scientific papers on this subject are appearing in image processing, computer vision and pattern analysis contexts, or use techniques of these areas. In this paper, we will survey the recent studies on automatic analysis of facial beauty, and discuss research lines and practical application
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