670 research outputs found

    An experimental investigation of the laminar horseshoe vortex around an emerging obstacle

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    An emerging long obstacle placed in a boundary layer developing under a free-surface generates a complex horseshoe vortex (HSV) system, which is composed of a set of vortices exhibiting a rich variety of dynamics. The present experimental study examines such flow structure and characterizes precisely, using PIV measurements, the evolution of the HSV geometrical and dynamical properties over a wide range of dimensionless parameters (Reynolds number Reh[750,8300]Re_h \in [750, 8300], boundary layer development ratio h/δ[1.25,4.25]h/\delta \in [1.25, 4.25] and obstacle aspect ratio W/h[0.67,2.33]W/h \in [0.67, 2.33]). The dynamical study of the HSV is based on the categorization of the HSV vortices motion into an enhanced specific bi-dimensional typology, separating a coherent (due to vortex-vortex interactions) and an irregular evolution (due to appearance of small-scale instabilities). This precise categorization is made possible thanks to the use of vortex tracking methods applied on PIV measurements, A semi-empirical model for the HSV vortices motion is then proposed to highlight some important mechanisms of the HSV dynamics, as (i) the influence of the surrounding vortices on a vortex motion and (ii) the presence of a phase shift between the motion of all vortices. The study of the HSV geometrical properties (vortex position and characteristic lengths and frequencies) evolution with the flow parameters shows that strong dependencies exist between the streamwise extension of the HSV and the obstacle width, and between the HSV vortex number and its elongation. Comparison of these data with prior studies for immersed obstacles reveals that emerging obstacles lead to greater adverse pressure gradients and down-flows in front of the obstacle

    Decision-analytic evaluation of the comparative effectiveness and cost-effectiveness of strategies to prevent breast and ovarian cancer in German women with BRCA-1/2 mutations

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    Abstract Background Women with inherited mutations in the BRCA1 or BRCA2 genes have increased lifetime risks for developing breast and/or ovarian cancer and may develop these cancers around the age of 30 years. Therefore, prevention of breast and ovarian cancer in these women may need to start relatively early in life. In this study we systematically evaluate the long-term effectiveness and cost effectiveness of different prevention strategies for breast and ovarian cancer in women with BRCA-1/2 mutation in Germany. Methods A decision-analytic Markov model simulating lifetime breast and ovarian cancer development in BRCA-1/2 carriers was developed. Different strategies including intensified surveillance (IS), prophylactic bilateral mastectomy (PBM), and prophylactic bilateral salpingo-oophorectomy (PBSO) alone or in combination at different ages were evaluated. German clinical, epidemiological, and economic (in 2022 Euro) data were used. Outcomes included cancer incidences, mortality, life years (LYs), quality-adjusted life years (QALYs), and discounted incremental cost-effectiveness ratios (ICER). We adopted the German health-care system perspective and discounted costs and health effects with 3% annually. Results All intervention strategies are more effective and less costly than IS alone. Prevention with PBM plus PBSO at age 30 maximizes life expectancy with 6.3 LYs gained, whereas PBM at age 30 with delayed PBSO at age 35 improves quality of life with 11.1 QALYs gained, when compared to IS alone. A further delay of PBSO was associated with lower effectiveness. Both strategies are cost effective with ICERs significantly below 10,000 EUR/LYG or QALY. Conclusion Based on our results, PBM at age 30 plus PBSO between age 30 and 40 prolongs life and is cost effective in women with BRCA-1/2 mutations in Germany. Serial preventive surgeries with delayed PBSO potentially improve quality of life for women. However, delaying PBM and/or PBSO further may lead to increased mortality and reduced QALYs

    Manajemen Rantai Pasok Beras di Kecamatan Kotamobagu Selatan, Kota Kotamobagu

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    This study aims to determine the rice supply chain management. Data retrieval is done is primary data and secondary data. Primary data were obtained through a list of questions that had been prepared, while secondary data obtained from relevant agencies to study the Agriculture Department Kotamobagu. The sampling method is done by snowball sampling, where the sample is obtained based on information from first responders then browse to the next respondent. Data presented in tables and descriptive analysis to describe the characteristics of respondents. The concept of measuring variables used is the procurement, planning and control, operations or production and delivery or distribution. These results indicate that the rice supply chain management in the District of South Kotamobagu starting from farmers in the form of grain and then distributed by the farmers to millers. Activities drying, milling and packaging is done by the rice mill, then sold to wholesalers and retailers or directly to the final consumer in the form of rice. The process of the activities in the implementation of supply chain management is divided into three main streams are managed properly, the flow of goods / products, financial flows and the flow of information so that the production of rice in each member of the supply chain is always available

    Herpes simplex Natural Remedies for Herpes simplex

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    Abstract Herpes simplex is a common viral infection of th

    Immunoglobulin A1 Protease, an Exoenzyme of Pathogenic Neisseriae, Is a Potent Inducer of Proinflammatory Cytokines

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    A characteristic of human pathogenic Neisseriae is the production and secretion of an immunoglobulin (Ig)A1-specific serine protease (IgA1 protease) that cleaves preferentially human IgA1 and other target proteins. Here we show a novel function for native IgA1 protease, i.e., the induction of proinflammatory cytokines such as tumor necrosis factor (TNF)-α, interleukin (IL)-1β, IL-6, and IL-8 from peripheral blood mononuclear cells. The capacity of IgA1 protease to elicit such cytokine responses in monocytes was enhanced in the presence of T lymphocytes. IgA1 protease did not induce the regulatory cytokine IL-10, which was, however, found in response to lipopolysaccharide and phytohemagglutinin. The immunomodulatory effects caused by IgA1 protease require a native form of the enzyme, and denaturation abolished cytokine induction. However, the proteolytic activity is not required for the cytokine induction by IgA1 protease. Our results indicate that IgA1 protease exhibits important immunostimulatory properties and may contribute substantially to the pathogenesis of neisserial infections by inducing large amounts of TNF-α and other proinflammatory cytokines. In particular, IgA1 protease may represent a key virulence determinant of bacterial meningitis
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