787 research outputs found

    The clinical characteristics of benign oral mucosal tumors

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    Objectives: To investigate the clinical characteristics and pre-biopsy provisional diagnoses of benign oral mucosal tumors. Material and Methods: A 10- year retrospective analysis of all benign tumors of the oral mucosa, from a univer- Methods: A 10- year retrospective analysis of all benign tumors of the oral mucosa, from a univer - sity- affiliated oral and maxillofacial surgery department. Results: 146 benign tumors were included. The mean age was 49.6 years, with an approximately equal gender dis - tribution. The most prevalent tumor types were lipomatous tumors (27.4%), vascular (23.3%), and salivary gland tumors (16.5%). Tongue, labial and buccal mucosa were the most frequently involved sites. The vast majority (98.6%) presented as non-ulcerated masses. Only 2 (1.4%) presented as ulcerated masses. The clinical provisional diagnosis correctly classified lesions as non-malignant in 93.3%. In only 9 (6.7%) suspicion of malignancy was in - cluded in the provisional diagnosis. However, benign neoplasia was unsuspected in 42.1% of tumors. These cases were clinically classified as reactive. Conclusions: Benign tumors were most likely to be clinically correctly classified as non-malignant, but even in the setting of experienced oral surgeons, neoplasia was unsuspected in more than 40% of cases. This data strongly supports the need to biopsy every oral mucosal mass, since inaccurate clinical evaluation of the lesion's biological nature was a frequent event

    Is Routine Multivitamin Supplementation Necessary in US Chronic Adult Hemodialysis Patients? A Systematic Review

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    Because of concern that United States (US) chronic hemodialysis patients are at high risk for the development of vitamin deficiencies, the great majority of such patients are routinely supplemented with a multivitamin. This policy is supported by major US dialysis providers and nonprofit organizations. Yet routine multivitamin supplementation expands hemodialysis patients' already large pill burden, probably accounts for many millions of dollars in annual costs, and in light of previous reports may even carry with it the possibility of increased risk of adverse outcomes. An analysis of the benefits of routine multivitamin supplementation in US patients is therefore in order. We performed a systematic review of the medical literature between 1970 and 2014 using the Ovid MEDLINE database to address this question. We conclude that there is insufficient evidence to support routine multivitamin use and recommend that the decision to supplement be made on an individual basis

    Extremal Optimization at the Phase Transition of the 3-Coloring Problem

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    We investigate the phase transition of the 3-coloring problem on random graphs, using the extremal optimization heuristic. 3-coloring is among the hardest combinatorial optimization problems and is closely related to a 3-state anti-ferromagnetic Potts model. Like many other such optimization problems, it has been shown to exhibit a phase transition in its ground state behavior under variation of a system parameter: the graph's mean vertex degree. This phase transition is often associated with the instances of highest complexity. We use extremal optimization to measure the ground state cost and the ``backbone'', an order parameter related to ground state overlap, averaged over a large number of instances near the transition for random graphs of size nn up to 512. For graphs up to this size, benchmarks show that extremal optimization reaches ground states and explores a sufficient number of them to give the correct backbone value after about O(n3.5)O(n^{3.5}) update steps. Finite size scaling gives a critical mean degree value αc=4.703(28)\alpha_{\rm c}=4.703(28). Furthermore, the exploration of the degenerate ground states indicates that the backbone order parameter, measuring the constrainedness of the problem, exhibits a first-order phase transition.Comment: RevTex4, 8 pages, 4 postscript figures, related information available at http://www.physics.emory.edu/faculty/boettcher

    The Peculiar Phase Structure of Random Graph Bisection

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    The mincut graph bisection problem involves partitioning the n vertices of a graph into disjoint subsets, each containing exactly n/2 vertices, while minimizing the number of "cut" edges with an endpoint in each subset. When considered over sparse random graphs, the phase structure of the graph bisection problem displays certain familiar properties, but also some surprises. It is known that when the mean degree is below the critical value of 2 log 2, the cutsize is zero with high probability. We study how the minimum cutsize increases with mean degree above this critical threshold, finding a new analytical upper bound that improves considerably upon previous bounds. Combined with recent results on expander graphs, our bound suggests the unusual scenario that random graph bisection is replica symmetric up to and beyond the critical threshold, with a replica symmetry breaking transition possibly taking place above the threshold. An intriguing algorithmic consequence is that although the problem is NP-hard, we can find near-optimal cutsizes (whose ratio to the optimal value approaches 1 asymptotically) in polynomial time for typical instances near the phase transition.Comment: substantially revised section 2, changed figures 3, 4 and 6, made minor stylistic changes and added reference

    Cell-to-cell variability of alternative RNA splicing

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    The role of mRNA processing in gene expression variability is poorly characterized. This study investigates the extent of cell-to-cell variability of alternative RNA splicing in mammalian cells using single-molecule imaging of CAPRIN1 and MKNK2 splice isoforms

    Personal Attitudes Toward Weight in Overweight and Obese US Hemodialysis Patients

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    Objective Overweight and obesity have become increasingly common among end-stage renal disease patients on hemodialysis. Yet, little attention has been given to what hemodialysis patients themselves think of their weight, how they perceive it affects their health, and their attitudes about or desire for weight reduction. We explored these issues using a survey that we designed specifically for the dialysis population. Design and Methods Sixty-six chronic hemodialysis patients from a US urban center with a body mass index ≥25 kg/m2 and stable weight were recruited to participate in a cross-sectional study. The 12-question weight-related survey was validated by retesting a random portion of the study population. Results Based on test–retest results, the survey had good to excellent validity. Seventy-nine percent of patients were black, 49% were male, 29% were overweight, and 71% were obese. In general, the patients underestimated their weight excess though 73% were interested in weight loss, of whom nearly half reported attempting to do so mostly through diet and exercise. The majority of participants interested in losing weight felt that doing so would improve their physical and emotional health. The most common barrier to weight reduction was a belief that it was too difficult (55%), followed by a lack of motivation, money, time, resources, and knowledge. Diet was the most common weight loss strategy (85%) considered, whereas bariatric surgery was the least common (6.1%). Conclusions A majority of overweight and obese hemodialysis patients believe their excess weight is adversely impacting their health and quality of life and therefore wish to lose weight

    The effect of algal turbidity on larval performance and the ontogeny of digestive enzymes in the grey mullet (Mugil cephalus)

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    A study comprised of two trials determined the effects of water turbidity produced by live microalgae and inert clay particles on the larval rearing of grey mullet (Mugil cephalus). Trial 1 evaluated the effect of microalgae produced water turbidity on grey mullet larval performance and digestive tract (DT) enzyme ontogeny. Two microalgae (Nannochloropsis oculata and Isochrysis galbana) water turbidity levels (0.76 and 1.20 NTU, respectively) and a non-microalgae control (0.26 NTU) were investigated on 2 to 23 dph grey mullet larvae. The higher turbidity (1.2 NTU) larvae (5 dph) consumed markedly (P < .05) more rotifers than other treatment fish, independently of the microalgae type. There was no clear effect of the turbidity treatments on DT enzyme ontogeny. However, in all treatments lipase and alkaline proteases appeared to be modulated by the diet. Alkaline phosphatase activity was ca. 8 times higher and α-amylase activity increased 5.3 times in 79 dph fish compared to 40 dph individuals. The ratio of alkaline phosphatase and leucine-alanine aminopeptidase indicated gut maturation occurred around 61 dph. Trial 2 compared the most effective N.occulata produced turbidity level (1.2 NTU) with the identical water turbidity produced by inert clay on larval performance. M. cephalus larvae exposed to high algal turbidity demonstrated superior performance (P < .05), in terms of rotifer ingestion, dry weight gain and survival, compared to cohorts reared under the clay treatment and the lower microalgae produced turbidity. These findings suggested that water algal turbidity is not the dominant factor determining improved grey mullet larval performance.info:eu-repo/semantics/acceptedVersio

    Price and service competition with maintenance service bundling

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    In many equipment manufacturing industries, firms compete with each other not only on products price, but also on maintenance service. More and more traditional products oriented firms are offering their customers products bundled with maintenance service (P&S bundles). In this study, we examine firms’ incentive to offer customers products bundling with long-term maintenance or repair support service in a duopoly competitive environment. When providing P&S bundles, a firm need to determine the service level (in terms of average response time guarantee for the service in this paper) to offer and needs to build a service facility to handle the maintenance service requirements. Based on the analysis of three sub-game models, we characterize the market conditions in which only one firm, both firms or neither firm will offer P&S bundles. Finally, we analyze the affects of several market factors on firms’ strategy choices
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