1,856 research outputs found

    Unveiling Hidden Values of Optimization Models with Metaheuristic Approach

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    Considering that the decision making process for constrained optimization problem is based on modeling, there is always room for alternative solutions because there is usually a gap between the model and the real problem it depicts. This study looks into the problem of finding such alternative solutions, the non-optimal solutions of interest for constrained optimization models, the SoI problem. SoI problems subsume finding feasible solutions of interest (FoIs) and infeasible solutions of interest (IoIs). In all cases, the interest addressed is post-solution analysis in one form or another. Post-solution analysis of a constrained optimization model occurs after the model has been solved and a good or optimal solution for it has been found. At this point, sensitivity analysis and other questions of import for decision making come into play and for this purpose the SoIs can be very valuable. An evolutionary computation approach (in particular, a population-based metaheuristic) is proposed for solving the SoI problem and a systematic approach with a feasible-infeasible- two-population genetic algorithm is demonstrated. In this study, the effectiveness of the proposed approach on finding SoIs is demonstrated with generalized assignment problems and generalized quadratic assignment problems. Also, the applications of the proposed approach on the multi-objective optimization and robust-optimization issues are examined and illustrated with two-sided matching problems and flowshop scheduling problems respectively

    Effective Heuristic Methods for Finding Non-Optimal Solutions of Interest in Constrained Optimization Models

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    This paper introduces the SoI problem, that of finding non-optimal solutions of interest for constrained optimization models. SoI problems subsume finding FoIs (feasible solutions of interest), and IoIs (infeasible solutions of interest). In all cases, the interest addressed is post-solution analysis in one form or another. Post-solution analysis of a constrained optimization model occurs after the model has been solved and a good or optimal solution for it has been found. At this point, sensitivity analysis and other questions of import for decision making (discussed in the paper) come into play and for this purpose the SoIs can be of considerable value. The paper presents examples that demonstrate this and reports on a systematic approach, using evolutionary computation, for obtaining both FoIs and IoIs

    Preparation of ZnO membrane by chemical bath deposition method via regulated acidity

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    In this study, the chemical bath deposition (CBD) method was used to deposit a ZnO membrane on an indium tin oxide glass substrate. The deposition reaction working temperature was 90°C and the temperature retaining deposition time was 60 min; NH4OH was used to control the pH value in the range 10~11, and after deposition, the specimen was thermally annealed in air. Annealing temperatures in the range of 100~500°C were adopted to investigate the thin-film growth behavior and the effect of processing temperature on the ZnO membrane performance during the annealing process. The process parameters related to the preparation of the ZnO membrane by CBD were the pH value, retaining temperature deposition time, working temperature for the deposition reaction, annealing thermal processing, and so on. Scanning electron microscopy (SEM) was used to observe and analyze the surface morphology and microstructure of the membrane cross section, and UV-Vis spectrometry was used to measure the optical transmission of the ZnO membrane in air at different annealing temperatures. We investigated the effects of different pH values on the growth of the ZnO membrane by CBD. The experimental results show that at a pH of 10.7, we can obtain a transparent and electrically conductive ZnO thin film with a thickness of 240 nm, which has very good optical transmission and high electrical mobility at an annealing temperature of 200°C. Keywords: Chemical bath deposition, ZnO membrane, pH valu

    Cancer and Radiation Therapy: Current Advances and Future Directions

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    In recent years remarkable progress has been made towards the understanding of proposed hallmarks of cancer development and treatment. However with its increasing incidence, the clinical management of cancer continues to be a challenge for the 21st century. Treatment modalities comprise of radiation therapy, surgery, chemotherapy, immunotherapy and hormonal therapy. Radiation therapy remains an important component of cancer treatment with approximately 50% of all cancer patients receiving radiation therapy during their course of illness; it contributes towards 40% of curative treatment for cancer. The main goal of radiation therapy is to deprive cancer cells of their multiplication (cell division) potential. Celebrating a century of advances since Marie Curie won her second Nobel Prize for her research into radium, 2011 has been designated the Year of Radiation therapy in the UK. Over the last 100 years, ongoing advances in the techniques of radiation treatment and progress made in understanding the biology of cancer cell responses to radiation will endeavor to increase the survival and reduce treatment side effects for cancer patients. In this review, principles, application and advances in radiation therapy with their biological end points are discussed

    Fibroblast Growth Factor Receptor 3 Is a Negative Regulator of Bone Growth

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    AbstractEndochondral ossification is a major mode of bone formation that occurs as chondrocytes undergo proliferation, hypertrophy, cell death, and osteoblastic replacement. We have identified a role for fibroblast growth factor receptor 3 (FGFR-3) in this process by disrupting the murine Fgfr-3 gene to produce severe and progressive bone dysplasia with enhanced and prolonged endochondral bone growth. This growth is accompanied by expansion of proliferating and hypertrophic chondrocytes within the cartilaginous growth plate. Thus, FGFR-3 appears to regulate endochondral ossification by an essentially negative mechanism, limiting rather than promoting osteogenesis. In light of these mouse results, certain human disorders, such as achondroplasia, can be interpreted as gain-of-function mutations that activate the fundamentally negative growth control exerted by the FGFR-3 kinase

    Intrastrain and interstrain genetic variation within a paralogous gene family in Chlamydia pneumoniae

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    BACKGROUND: Chlamydia pneumoniae causes human respiratory diseases and has recently been associated with atherosclerosis. Analysis of the three recently published C. pneumoniae genomes has led to the identification of a new gene family (the Cpn 1054 family) that consists of 11 predicted genes and gene fragments. Each member encodes a polypeptide with a hydrophobic domain characteristic of proteins localized to the inclusion membrane. RESULTS: Comparative analysis of this gene family within the published genome sequences provided evidence that multiple levels of genetic variation are evident within this single collection of paralogous genes. Frameshift mutations are found that result in both truncated gene products and pseudogenes that vary among isolates. Several genes in this family contain polycytosine (polyC) tracts either upstream or within the terminal 5' end of the predicted coding sequence. The length of the polyC stretch varies between paralogous genes and within single genes in the three genomes. Sequence analysis of genomic DNA from a collection of 12 C. pneumoniae clinical isolates was used to determine the extent of the variation in the Cpn 1054 gene family. CONCLUSIONS: These studies demonstrate that sequence variability is present both among strains and within strains at several of the loci. In particular, changes in the length of the polyC tract associated with the different Cpn 1054 gene family members are common within each tested C. pneumoniae isolate. The variability identified within this newly described gene family may modulate either phase or antigenic variation and subsequent physiologic diversity within a C. pneumoniae population

    Nitroprusside modulates pulmonary vein arrhythmogenic activity

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    <p>Abstract</p> <p>Background</p> <p>Pulmonary veins (PVs) are the most important sources of ectopic beats with the initiation of paroxysmal atrial fibrillation, or the foci of ectopic atrial tachycardia and focal atrial fibrillation. Elimination of nitric oxide (NO) enhances cardiac triggered activity, and NO can decrease PV arrhythmogensis through mechano-electrical feedback. However, it is not clear whether NO may have direct electrophysiological effects on PV cardiomyocytes. This study is aimed to study the effects of nitroprusside (NO donor), on the ionic currents and arrhythmogenic activity of single cardiomyocytes from the PVs.</p> <p>Methods</p> <p>Single PV cardiomyocytes were isolated from the canine PVs. The action potential and ionic currents were investigated in isolated single canine PV cardiomyocytes before and after sodium nitroprusside (80 μM,) using the whole-cell patch clamp technique.</p> <p>Results</p> <p>Nitroprusside decreased PV cardiomyocytes spontaneous beating rates from 1.7 ± 0.3 Hz to 0.5 ± 0.4 Hz in 9 cells (P < 0.05); suppressed delayed afterdepolarization in 4 (80%) of 5 PV cardiomyocytes. Nitroprusside inhibited L-type calcium currents, transient outward currents and transient inward current, but increased delayed rectified potassium currents.</p> <p>Conclusion</p> <p>Nitroprusside regulates the electrical activity of PV cardiomyocytes, which suggests that NO may play a role in PV arrhythmogenesis.</p

    Information and communication technology to link criminal justice reentrants to HIV care in the community

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    The United States has the world’s highest prison population, and an estimated one in seven HIV-positive persons in the USA passes through a correctional facility annually. Given this, it is critical to develop innovative and effective approaches to support HIV treatment and retention in care among HIV-positive individuals involved in the criminal justice (CJ) system. Information and communication technologies (ICTs), including mobile health (mHealth) interventions, may offer one component of a successful strategy for linkage/retention in care. We describe CARE+ Corrections, a randomized controlled trial (RCT) study now underway in Washington, that will evaluate the combined effect of computerized motivational interview counseling and postrelease short message service (SMS) text message reminders to increase antiretroviral therapy (ART) adherence and linkage and retention in care among HIV-infected persons involved in the criminal justice system. In this report, we describe the development of this ICT/mHealth intervention, outline the study procedures used to evaluate this intervention, and summarize the implications for the mHealth knowledge base

    Cbfbeta reduces Cbfbeta-SMMHC-associated acute myeloid leukemia in mice

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    The gene encoding for core-binding factor beta (CBFbeta) is altered in acute myeloid leukemia samples with an inversion in chromosome 16, expressing the fusion protein CBFbeta-SMMHC. Previous studies have shown that this oncoprotein interferes with hematopoietic differentiation and proliferation and participates in leukemia development. In this study, we provide evidence that Cbfbeta modulates the oncogenic function of this fusion protein. We show that Cbfbeta plays an important role in proliferation of hematopoietic progenitors expressing Cbfbeta-SMMHC in vitro. In addition, Cbfbeta-SMMHC-mediated leukemia development is accelerated in the absence of Cbfbeta. These results indicate that the balance between Cbfbeta and Cbfbeta-SMMHC directly affects leukemia development, and suggest that CBF-specific therapeutic molecules should target CBFbeta-SMMHC function while maintaining CBFbeta activity
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