735 research outputs found

    Deoxidation and Inclusion Control for Alloy Steel

    Get PDF
    DEOXIDATION of quality steels is directed toward the casting of sound ingots free from excessive segregation, having good rolling and forging characteristics, and containing it minimum of harmful impurity elements and inclusions. In addition, deoxidation is employed for grain size control to promote maximum toughness of the steel. These objectives are a chieved by selection of suitable charge material, slag control and initial deoxi-dation practice in the furnace, and final deoxidation practice in the ladle. Although much has been learned of the physical chemistry of the process,the art of steel-making is still in large part empirical, and successful practices are somewhat difficult to rationalize. For this reason, equilibrium relations in the iron-oxygen deoxidizer systems are important, but the kinetics of deoxidation and the sequence of operations may be more significant to the operator

    Human Mesenchymal Stromal Cells Decrease Mortality Following Intestinal Ischemia and Reperfusion Injury

    Get PDF
    Background Cellular therapy is a novel treatment option for intestinal ischemia. Bone marrow–derived mesenchymal stromal cells (BMSCs) have previously been shown to abate the damage caused by intestinal ischemia/reperfusion (I/R) injury. We therefore hypothesized that (1) human BMSCs (hBMSCs) would produce more beneficial growth factors and lower levels of proinflammatory mediators compared to differentiated cells, (2) direct application of hBMSCs to ischemic intestine would decrease mortality after injury, and (3) decreased mortality would be associated with an altered intestinal and hepatic inflammatory response. Methods Adult hBMSCs and keratinocytes were cultured on polystyrene flasks. For in vitro experiments, cells were exposed to tumor necrosis factor, lipopolysaccharides, or 2% oxygen for 24 h. Supernatants were then analyzed for growth factors and chemokines by multiplex assay. For in vivo experiments, 8- to 12-wk-old male C57Bl6J mice were anesthetized and underwent a midline laparotomy. Experimental groups were exposed to temporary superior mesenteric artery occlusion for 60 min. Immediately after ischemia, 2 × 106 hBMSCs or keratinocytes in phosphate-buffered saline were placed into the peritoneal cavity. Animals were then closed and allowed to recover for 6 h (molecular/histologic analysis) or 7 d (survival analysis). After 6-h reperfusion, animals were euthanized. Intestines and livers were harvested and analyzed for inflammatory chemokines, growth factors, and histologic changes. Results hBMSCs expressed higher levels of human interleukin (IL) 6, IL-8, vascular endothelial growth factor (VEGF), and epidermal growth factor and lower levels of IL-1, IL-3, IL-7, and granulocyte-monocyte colony-stimulating factor after stimulation. In vivo, I/R resulted in significant mortality (70% mortality), whereas application of hBMSCs after ischemia decreased mortality to 10% in a dose-dependent fashion (P = 0.004). Keratinocyte therapy offered no improvements in mortality above I/R. Histologic profiles were equivalent between ischemic groups, regardless of the application of hBMSCs or keratinocytes. Cellular therapy yielded significantly decreased murine intestinal levels of soluble activin receptor-like kinase 1, betacellulin, and endothelin, whereas increasing levels of eotaxin, monokine induced by gamma interferon (MIG), monocyte chemoattractant protein 1, IL-6, granulocyte colony-stimulating factor (G-CSF), and interferon gamma-induced protein 10 (IP-10) from ischemia were appreciated. hBMSC therapy yielded significantly higher expression of murine intestinal VEGF and lower levels of intestinal MIG compared to keratinocyte therapy. Application of hBMSCs after ischemia yielded significantly lower murine levels of hepatic MIG, IP-10, and G-CSF compared to keratinocyte therapy. Conclusions Human BMSCs produce multiple beneficial growth factors. Direct application of hBMSCs to the peritoneal cavity after intestinal I/R decreased mortality by 60%. Improved outcomes with hBMSC therapy were not associated with improved histologic profiles in this model. hBMSC therapy was associated with higher VEGF in intestines and lower levels of proinflammtory MIG, IP-10, and G-CSF in liver tissue after ischemia, suggesting that reperfusion with hBMSC therapy may alter survival by modulating the systemic inflammatory response to ischemia

    Methodology for achieving GASB 34 modified approach compliance using U.S. Navy "Smart Base" facility management practices

    Get PDF
    Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Civil and Environmental Engineering, 2002.Includes bibliographical references (p. 101-102).by Michael D. Crafts.S.M

    How good was the profitability of British Railways, 1870-1912?

    Get PDF
    This paper provides new estimates of the return on capital employed (ROCE) for major British railway companies. It shows that ROCE was generally below the cost of capital after the mid-1870s and fell till the turn of the century. Addressing issues of cost inefficiency could have restored ROCE to an adequate level in the late 1890s but not in 1910. Declines in ROCE hit share prices and returns to shareholders were negative after 1897. Optimal portfolio analysis shows that, whilst railway securities would have had a substantial weight prior to this date, investors would have been justified in rushing to the exits thereafter

    Accounting for early job turnover in recent pediatric surgery fellowship graduates: An American Pediatric Surgical Association Membership and Credentials Committee study

    Get PDF
    PURPOSE: Employment opportunities for graduating pediatric surgeons vary from year to year. Significant turnover among new employees indicates fellowship graduates may be unsophisticated in choosing job opportunities which will ultimately be satisfactory for themselves and their families. The purpose of this study was to assess what career, life, and social factors contributed to the turnover rates among pediatric surgeons in their first employment position. METHODS: American Pediatric Surgical Association members who completed fellowship training between 2011 and 2016 were surveyed voluntarily. Only those who completed training in a pediatric surgery fellowship sanctioned by the American Board of Surgery and whose first employment involved the direct surgical care of patients were included. The survey was completed electronically and the results were evaluated using chi-squared analysis to determine which independent variables contributed to a dependent outcome of changing place of employment. RESULTS: 110 surveys were returned with respondents meeting inclusion criteria. 13 (11.8%) of the respondents changed jobs within the study period and 97 (88.2%) did not change jobs. Factors identified that likely contributed to changing jobs included a perceived lack of opportunity for career [p = <0.001] advancement and the desire to no longer work at an academic or teaching facility [p = 0.013]. Others factors included excessive case load [p = 0.006]; personal conflict with partners or staff [p = 0.007]; career goals unfulfilled by practice [p = 0.011]; lack of mentorship in partners [p = 0.026]; and desire to be closer to the surgeon's or their spouse's family [p = 0.002]. CONCLUSIONS: Several factors appear to play a role in motivating young pediatric surgeons to change jobs early in their careers. These factors should be taken into account by senior pediatric fellows and their advisors when considering job opportunities

    Three-Dimensional Printing and Its Applications in Otorhinolaryngology–Head and Neck Surgery

    Get PDF
    Objective Three-dimensional (3D)-printing technology is being employed in a variety of medical and surgical specialties to improve patient care and advance resident physician training. As the costs of implementing 3D printing have declined, the use of this technology has expanded, especially within surgical specialties. This article explores the types of 3D printing available, highlights the benefits and drawbacks of each methodology, provides examples of how 3D printing has been applied within the field of otolaryngology–head and neck surgery, discusses future innovations, and explores the financial impact of these advances. Data Sources Articles were identified from PubMed and Ovid MEDLINE. Review Methods PubMed and Ovid Medline were queried for English articles published between 2011 and 2016, including a few articles prior to this time as relevant examples. Search terms included 3-dimensional printing, 3D printing, otolaryngology, additive manufacturing, craniofacial, reconstruction, temporal bone, airway, sinus, cost, and anatomic models. Conclusions Three-dimensional printing has been used in recent years in otolaryngology for preoperative planning, education, prostheses, grafting, and reconstruction. Emerging technologies include the printing of tissue scaffolds for the auricle and nose, more realistic training models, and personalized implantable medical devices. Implications for Practice After the up-front costs of 3D printing are accounted for, its utilization in surgical models, patient-specific implants, and custom instruments can reduce operating room time and thus decrease costs. Educational and training models provide an opportunity to better visualize anomalies, practice surgical technique, predict problems that might arise, and improve quality by reducing mistakes

    Growth in densely populated Asia: implications for primary product exporters

    Get PDF
    Economic growth and integration in Asia is rapidly increasing the global economic importance of the region. To the extent that this growth continues and is strongest in natural resource-poor Asian economies, it will add to global demand for imports of primary products, to the benefit of (especially nearby) resource-abundant countries. How will global production, consumption and trade patterns change by 2030 in the course of such economic developments and structural changes? We address this question using the GTAP model and Version 8.1 of the 2007 GTAP database, together with supplementary data from a range of sources, to support projections of the global economy from 2007 to 2030 under various scenarios. Factor endowments and real gross domestic product are assumed to grow at exogenous rates, and trade-related policies are kept unchanged to generate a core baseline, which is compared with an alternative slower growth scenario. We also consider the impact of several policy changes aimed at increasing China's agricultural self-sufficiency relative to the 2030 baseline. Policy implications for countries of the Asia-Pacific region are drawn out in the final section

    Middle Ordovician Black River Ostracods from Michigan, Introduction and Part I The Nature of Macronotella

    Full text link
    293-314http://deepblue.lib.umich.edu/bitstream/2027.42/48341/2/ID182.pd

    State education as high-yield investment: human capital theory in European policy discourse

    Get PDF
    Human Capital Theory has been an increasingly important phenomenon in economic thought over the last 50 years. The central role it affords to education has become even more marked in recent years as the concept of the ‘knowledge economy’ has become a global concern. In this paper, the prevalence of Human Capital Theory within European educational policy discourse is explored. The paper examines a selection of policy documents from a number of disparate European national contexts and considers the extent to which the ideas of Human Capital Theory can be seen to be influential. In the second part of the paper, the implications of Human Capital Theory for education are considered, with a particular focus on the possible ramifications at a time of economic austerity. The paper argues that Human Capital Theory risks offering a diminished view of the person, a diminished view of education, but that with its sole focus on economic goals leaves room for educationists and others to argue for the educational, social, and moral values it ignores, and for the conception of the good life and good society it fails to mention
    corecore