217 research outputs found

    Eosinophilic Gastroenteritis as a Rare Cause of Recurrent Epigastric Pain

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    Eosinophilic gastroenteritis (EGE) is a rare inflammatory disorder of gastrointestinal tract characterized by eosinophilic infiltration of the bowel wall. It can mimic many gastrointestinal disorders due to its wide spectrum of presentations. Diagnose is mostly based on excluding other disorders and a high suspicion. Here we report a case of 26 year old man with a history of sever epigastric pain followed by nausea, vomiting since a few days before admission with final diagnosis of EGE

    Exploring Strategies Adopted by Adolescent Girls for Continuing Sports Activities

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    Background: Physical activity maintenance is an active process that requires active use of strategies and techniques for its maintenance. The present study was designed to understand these strategies from the viewpoints of adolescent girls, who are often significantly less physically active than their male counterparts. Methods: This study was a qualitative content analysis conducted through semi-structured interviews with 25 participants (16 adolescent girls, 7 mothers and two fathers). Data gathering was continued until data saturation. All the interviews were recorded, transcribed, and finally were analyzed by conventional content analysis using OneNote. Results: The Strategy of "strive for perfection", with categories of reviewing experiences and thoughtful decision making and activity, was the dominant strategy used by adolescent girls to continue their sport activities. Conclusion: Adolescent girls in the recent study facilitated the continuation of their sports activities through using cognitive and behavioral strategies appropriate to their conditions. Therefore, it seems that paying attention to creating conditions for adolescents to have their own choices, decisions and strategies is useful in the continuation of sports activities

    Online Weighted Degree-Bounded Steiner Networks via Novel Online Mixed Packing/Covering

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    We design the first online algorithm with poly-logarithmic competitive ratio for the edge-weighted degree-bounded Steiner forest (EW-DB-SF) problem and its generalized variant. We obtain our result by demonstrating a new generic approach for solving mixed packing/covering integer programs in the online paradigm. In EW-DB-SF, we are given an edge-weighted graph with a degree bound for every vertex. Given a root vertex in advance, we receive a sequence of terminal vertices in an online manner. Upon the arrival of a terminal, we need to augment our solution subgraph to connect the new terminal to the root. The goal is to minimize the total weight of the solution while respecting the degree bounds on the vertices. In the offline setting, edge-weighted degree-bounded Steiner tree (EW-DB-ST) and its many variations have been extensively studied since early eighties. Unfortunately, the recent advancements in the online network design problems are inherently difficult to adapt for degree-bounded problems. In particular, it is not known whether the fractional solution obtained by standard primal-dual techniques for mixed packing/covering LPs can be rounded online. In contrast, in this paper we obtain our result by using structural properties of the optimal solution, and reducing the EW-DB-SF problem to an exponential-size mixed packing/covering integer program in which every variable appears only once in covering constraints. We then design a generic integral algorithm for solving this restricted family of IPs. As mentioned above, we demonstrate a new technique for solving mixed packing/covering integer programs. Define the covering frequency k of a program as the maximum number of covering constraints in which a variable can participate. Let m denote the number of packing constraints. We design an online deterministic integral algorithm with competitive ratio of O(k*log(m)) for the mixed packing/covering integer programs. We prove the tightness of our result by providing a matching lower bound for any randomized algorithm. We note that our solution solely depends on m and k. Indeed, there can be exponentially many variables. Furthermore, our algorithm directly provides an integral solution, even if the integrality gap of the program is unbounded. We believe this technique can be used as an interesting alternative for the standard primal-dual techniques in solving online problems

    Nanoporous Polyether Sulfone Membrane, Preparation and Characterization: Effect of Porosity and Mean Pore Size on Performance

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    Flat sheet membranes were prepared by phase inversion technique using polyether sulfone (PES) dissolved in dimethylacetamide (DMAc) with and without adding polyvinylpyrrolidone (PVP) or polyethyleneglycol (PEG). The characteristics of the prepared membranes were evaluated using Scanning Electron Microscope (SEM) images, Atomic Force Microscopy (AFM), and Optical Contact Angle (OCA) measurements, and porosity tests. The porosity test and SEM images show that increasing additives to a certain value increases the porosity of the membrane. Also, as the coagulation bath temperature is increased, the porosity of the membrane is increased. The roughness of the membrane is increased by increasing the additive concentration. The analysis of AFM images confirms the nanoporous structure of the prepared membranes, and that the membranes with appropriate pore size distribution can be prepared by the applied method. Permeability tests using single-layer membranes show that the direct relationship between porosity and the flux of pure water or salt solution is dominated by the effect of applied additive while the salt rejection shows an inverse relationship with the mean pore size regardless of the applied additive. The salt permeation flux is a function of total porosity while the salt rejection is a function of surface porosity. Pervaporation tests show that both permeation flux and enrichment factor depend on the total porosity of the support membrane
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