387 research outputs found

    A heuristic for the container loading problem: A tertiary-tree-based dynamic space decomposition approach

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    Increasing fuel costs, post-911 security concerns, and economic globalization provide a strong incentive for container carriers to use available container space more efficiently, thereby minimizing the number of container trips and reducing socio-economic vulnerability. A heuristic algorithm based on a tertiary tree model is proposed to handle the container loading problem (CLP) with weakly heterogeneous boxes. A dynamic space decomposition method based on the tertiary tree structure is developed to partition the remaining container space after a block of homogeneous rectangular boxes is loaded into a container. This decomposition approach, together with an optimal-fitting sequencing and an inner-right-corner-occupying placement rule, permits a holistic loading strategy to pack a container. Comparative studies with existing algorithms and an illustrative example demonstrate the efficiency of this algorithm

    In Vivo Turnover of Tau and APP Metabolites in the Brains of Wild-Type and Tg2576 Mice: Greater Stability of sAPP in the β-Amyloid Depositing Mice

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    The metabolism of the amyloid precursor protein (APP) and tau are central to the pathobiology of Alzheimer's disease (AD). We have examined the in vivo turnover of APP, secreted APP (sAPP), Aβ and tau in the wild-type and Tg2576 mouse brain using cycloheximide to block protein synthesis. In spite of overexpression of APP in the Tg2576 mouse, APP is rapidly degraded, similar to the rapid turnover of the endogenous protein in the wild-type mouse. sAPP is cleared from the brain more slowly, particularly in the Tg2576 model where the half-life of both the endogenous murine and transgene-derived human sAPP is nearly doubled compared to wild-type mice. The important Aβ degrading enzymes neprilysin and IDE were found to be highly stable in the brain, and soluble Aβ40 and Aβ42 levels in both wild-type and Tg2576 mice rapidly declined following the depletion of APP. The cytoskeletal-associated protein tau was found to be highly stable in both wild-type and Tg2576 mice. Our findings unexpectedly show that of these various AD-relevant protein metabolites, sAPP turnover in the brain is the most different when comparing a wild-type mouse and a β-amyloid depositing, APP overexpressing transgenic model. Given the neurotrophic roles attributed to sAPP, the enhanced stability of sAPP in the β-amyloid depositing Tg2576 mice may represent a neuroprotective response

    Imiquimod 3.75% Cream Applied Daily to Treat Anogenital Warts: Combined Results from Women in Two Randomized, Placebo-Controlled Studies

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    Objective. To evaluate if new imiquimod formulations using a shorter treatment duration are safe and efficacious to treat anogenital warts. Methods. In two studies 534 women ≥12 years of age (mean 33.4) with 2–30 warts (mean 7.9) and total wart area ≥10 mm2 (mean 166.3) were randomized (1 : 2 : 2) to placebo (106), imiquimod 2.5% (212) or 3.75% (216) creams applied once daily until complete clearance or a maximum of 8 weeks. Results. For placebo, imiquimod 2.5% and 3.75%, respectively, complete clearance of all warts was achieved in 14.2%, 28.3%, and 36.6% of women (intent-to-treat, P = 0.008 imiquimod 2.5%, and P < 0.001 3.75% versus placebo). Mean changes in wart counts were −10.7%, −50.9%, and −63.5% (per-protocol, P < 0.001 each active versus placebo) and safety-related discontinuation rates 0.9%, 1.4%, and 2.3%. Conclusions. Imiquimod 3.75% applied daily for up to 8 weeks was well tolerated and superior to placebo in treating women with external anogenital warts

    High use of private providers for first healthcare seeking by drug-resistant tuberculosis patients: a cross-sectional study in Yangon, Myanmar.

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    BACKGROUND: Drug resistance is a growing challenge to tuberculosis (TB) control worldwide, but particularly salient to countries such as Myanmar, where the health system is fragmented across the public and private sector. A recent systematic review has identified a critical lack of evidence for local policymaking, particularly in relation to drivers of drug-resistance that could be the target of preventative efforts. To address this gap from a health systems perspective, our study investigates the healthcare-seeking behavior and preferences of recently diagnosed patients with drug-resistant tuberculosis (DR-TB), focusing on the use of private versus public healthcare providers. METHODS: The study was conducted in ten townships across Yangon with high DR-TB burden. Patients newly-diagnosed with DR-TB by GeneXpert were enrolled, and data on healthcare-seeking behavior and socio-economic characteristics were collected from patient records and interviews. A descriptive analysis of healthcare-seeking behavior was followed by the investigation of relationships between socio-economic factors and type of provider visited upon first feeling unwell, through univariate logistic regressions. RESULTS: Of 202 participants, only 8% reported first seeking care at public facilities, while 88% reported seeking care at private facilities upon first feeling unwell. Participants aged 25-34 (Odds Ratio = 0.33 [0.12-0.95]) and males (Odds Ratio = 0.39 [0.20-0.75]) were less likely to visit a private clinic or hospital than those aged 18-24 and females, respectively. In contrast, participants with higher income were more likely to utilize private providers. Prior to DR-TB diagnosis, 86% of participants took medications from private providers. After DR-TB diagnosis, only 7% of participants continued to take medications from private providers. CONCLUSION: In urban Myanmar, most patients shifted to being managed exclusively in the public sector after being formally diagnosed with DR-TB. However, since the vast majority of DR-TB patients first visited private providers in the period leading to diagnosis, related issues such as unregulated quality of care, potential delays to diagnosis, and lack of care continuity may greatly influence the emergence of drug-resistance. A greater understanding of the health system and these healthcare-seeking behaviors may simultaneously strengthen TB control programmes and reduce government and out-of-pocket expenditures on the management of DR-TB

    The Demise of Islet Allotransplantation in the US: A Call for an Urgent Regulatory Update The ISLETS FOR US Collaborative

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    Islet allotransplantation in the United States (US) is facing an imminent demise. Despite nearly three decades of progress in the field, an archaic regulatory framework has stymied US clinical practice. Current regulations do not reflect the state-of-the-art in clinical or technical practices. In the US, islets are considered biologic drugs and more than minimally manipulated human cell and tissue products (HCT/Ps). Across the world, human islets are appropriately defined as minimally manipulated tissue which has led to islet transplantation becoming a standard-of-care procedure for patients with type 1 diabetes mellitus and problematic hypoglycemia. As a result of the outdated US regulations, only eleven patients underwent allo-ITx in the US between 2011-2016 and all in the setting of a clinical trial. Herein, we describe the current regulations pertaining to islet transplantation in the United States. We explore the progress which has been made in the field and demonstrate why the regulatory framework must be updated to both, better reflect our current clinical practice and to deal with upcoming challenges. We propose specific updates to current regulations which are required for the renaissance of ethical, safe, effective, and affordable allo-ITx in the United States

    High CD8+ T Cell Activation Marks a Less Differentiated HIV-1 Specific CD8+ T Cell Response that Is Not Altered by Suppression of Viral Replication

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    The relationship of elevated T cell activation to altered T cell differentiation profiles, each defining features of HIV-1 infection, has not been extensively explored. We hypothesized that anti-retroviral suppression of T cell activation levels would lead to alterations in the T cell differentiation of total and HIV-1 specific CD8+ T cell responses among recently HIV-1 infected adults.We performed a longitudinal study simultaneously measuring T cell activation and maturation markers on both total and antigen-specific T cells in recently infected adults: prior to treatment; after the initiation of HAART; and after treatment was halted. Prior to treatment, HIV-1 Gag-specific CD8+ T cells were predominantly of a highly activated, intermediate memory (CD27+CD28-) phenotype, while CMV pp65-specific CD8+ T cells showed a late memory (CD27-CD28-), low activation phenotype. Participants with the highest fraction of late memory (CD27-CD28-) HIV-1-specific CD8+ T cells had higher CD4+ T cell counts (rho = +0.74, p = 0.004). In turn, those with the highest fraction of intermediate memory (CD27+ CD28-) HIV-1 specific CD8+ T cells had high total CD8+ T cell activation (rho = +0.68, p = 0.01), indicating poorer long-term clinical outcomes. The HIV-1 specific T cell differentiation profile was not readily altered by suppression of T cell activation following HAART treatment.A more differentiated, less activated HIV-1 specific CD8+ T cell response may be clinically protective. Anti-retroviral treatment initiated two to four months after infection lowered T cell activation but had no effect on the differentiation profile of the HIV-1-specific response. Intervention during the first month of acute infection may be required to shift the differentiation phenotype of HIV-1 specific responses to a more clinically favorable profile

    Modulation of SOCS protein expression influences the interferon responsiveness of human melanoma cells

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    <p>Abstract</p> <p>Background</p> <p>Endogenously produced interferons can regulate the growth of melanoma cells and are administered exogenously as therapeutic agents to patients with advanced cancer. We investigated the role of negative regulators of interferon signaling known as suppressors of cytokine signaling (SOCS) in mediating interferon-resistance in human melanoma cells.</p> <p>Methods</p> <p>Basal and interferon-alpha (IFN-α) or interferon-gamma (IFN-γ)-induced expression of SOCS1 and SOCS3 proteins was evaluated by immunoblot analysis in a panel of n = 10 metastatic human melanoma cell lines, in human embryonic melanocytes (HEM), and radial or vertical growth phase melanoma cells. Over-expression of SOCS1 and SOCS3 proteins in melanoma cells was achieved using the PINCO retroviral vector, while siRNA were used to inhibit SOCS1 and SOCS3 expression. Tyr<sup>701</sup>-phosphorylated STAT1 (P-STAT1) was measured by intracellular flow cytometry and IFN-stimulated gene expression was measured by Real Time PCR.</p> <p>Results</p> <p>SOCS1 and SOCS3 proteins were expressed at basal levels in melanocytes and in all melanoma cell lines examined. Expression of the SOCS1 and SOCS3 proteins was also enhanced following stimulation of a subset of cell lines with IFN-α or IFN-γ. Over-expression of SOCS proteins in melanoma cell lines led to significant inhibition of Tyr<sup>701</sup>-phosphorylated STAT1 (P-STAT1) and gene expression following stimulation with IFN-α (IFIT2, OAS-1, ISG-15) or IFN-γ (IRF1). Conversely, siRNA inhibition of SOCS1 and SOCS3 expression in melanoma cells enhanced their responsiveness to interferon stimulation.</p> <p>Conclusions</p> <p>These data demonstrate that SOCS proteins are expressed in human melanoma cell lines and their modulation can influence the responsiveness of melanoma cells to IFN-α and IFN-γ.</p

    Rapid Processing of Both Reward Probability and Reward Uncertainty in the Human Anterior Cingulate Cortex

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    Reward probability and uncertainty are two fundamental parameters of decision making. Whereas reward probability indicates the prospect of winning, reward uncertainty, measured as the variance of probability, indicates the degree of risk. Several lines of evidence have suggested that the anterior cingulate cortex (ACC) plays an important role in reward processing. What is lacking is a quantitative analysis of the encoding of reward probability and uncertainty in the human ACC. In this study, we addressed this issue by analyzing the feedback-related negativity (FRN), an event-related potential (ERP) component that reflects the ACC activity, in a simple gambling task in which reward probability and uncertainty were parametrically manipulated through predicting cues. Results showed that at the outcome evaluation phase, while both win and loss-related FRN amplitudes increased as the probability of win or loss decreased, only the win-related FRN was modulated by reward uncertainty. This study demonstrates the rapid encoding of reward probability and uncertainty in the human ACC and offers new insights into the functions of the ACC

    A Genetic and Structural Study of Genome Rearrangements Mediated by High Copy Repeat Ty1 Elements

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    Ty elements are high copy number, dispersed repeated sequences in the Saccharomyces cerevisiae genome known to mediate gross chromosomal rearrangements (GCRs). Here we found that introduction of Ty912, a previously identified Ty1 element, onto the non-essential terminal region of the left arm of chromosome V led to a 380-fold increase in the rate of accumulating GCRs in a wild-type strain. A survey of 48 different mutations identified those that either increased or decreased the rate of Ty-mediated GCRs and demonstrated that suppression of Ty-mediated GCRs differs from that of both low copy repeat sequence- and single copy sequence-mediated GCRs. The majority of the Ty912-mediated GCRs observed were monocentric nonreciprocal translocations mediated by RAD52-dependent homologous recombination (HR) between Ty912 and a Ty element on another chromosome arm. The remaining Ty912-mediated GCRs appeared to involve Ty912-mediated formation of unstable dicentric translocation chromosomes that were resolved by one or more Ty-mediated breakage-fusion-bridge cycles. Overall, the results demonstrate that the Ty912-mediated GCR assay is an excellent model for understanding mechanisms and pathways that suppress genome rearrangements mediated by high copy number repeat sequences, as well as the mechanisms by which such rearrangements occur
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