989 research outputs found

    Feeding Frequency Affects Cultured Rat Pituitary Cells in Low Gravity

    Get PDF
    In this report, we describe the results of a rat pituitary cell culture experiment done on STS-65 in which the effect of cell feeding on the release of the six anterior pituitary hormones was studied. We found complex microgravity related interactions between the frequency of cell feeding and the quantity and quality (i.e. biological activity) of some of the six hormones released in flight. Analyses of growth hormone (GH) released from cells into culture media on different mission days using gel filtration and ion exchange chromatography yielded qualitatively similar results between ground and flight samples. Lack of cell feeding resulted in extensive cell clumping in flight (but not ground) cultures. Vigorous fibroblast growth occurred in both ground and flight cultures fed 4 times. These results are interpreted within the context of autocrine and or paracrine feedback interactions. Finally the payload specialist successfully prepared a fresh trypsin solution in microgravity, detached the cells from their surface and reinserted them back into the culture chamber. These cells reattached and continued to release hormone in microgravity. In summary, this experiment shows that pituitary cells are microgravity sensitive and that coupled operations routinely associated with laboratory cel1 culture can also be accomplished in low gravity

    Bioprocessing in Microgravity: Applications of Continuous Flow Electrophoresis to Rat Anterior Pituitary Particles

    Get PDF
    In this report we describe the results of a continuous flow electrophoresis (CFE) experiment done on STS-65 in which we tested the idea that intracellular growth hormone (GH) particles contained in a cell lysate prepared from cultured rat anterior pituitary cells in microgravity might have different electrophoretic mobilities from those in a synchronous ground control cell lysate. Collectively, the results suggested that CFE processing in microgravity was better than on earth; more samples could be processed at a time (6 x) and more variant forms of GH molecules could be resolved as well. We had also hoped to carry out a pituitary cell CFE experiment, but failure of the hardware required that the actual cell electrophoresis trials be done on earth shortly after Shuttle landing. Data from these experiments showed that space-flown cells possessed a higher electrophoretic mobility than ground control cells, thereby offering evidence for the idea that exposure of cultured cells to microgravity can change their net surface charge-density especially when the cells are fed. Collectively, the results from this pituitary cell experiment document the advantage of using coupled cell culture and CFE techniques in the microgravity environment

    Nocardia brain abscess - case report and literature review

    Get PDF
    Background and purposeNocardia species is an aerobic soil-saprophyte bacterium, responsible for rare opportunistic infections, mainly reported in immunocompromised patients. Nocardia brain abscess accounts for 1 to 2% of cerebral abscess. Abscesses are mainly located in the brain stem. Prognosis is poor.Methods The authors report one biloculated cerebral abscess case located in the left cerebellar and occipital lobes. We describe clinical, radiological and bacteriological findings and management; we also a review literature on Nocardia cerebral abscess.Case report A 56 year old man who was immunosuppressed, presented with headache and cerebellar syndrome. Head Computerised Tomography showed an irregularly enhancing cystic lesion in the left cerebellar and occipital lobes. He underwent posterior fossa cranitomy and chemotherapy that included high doses of Sulfamethoxazole-Trimethoprim and cefotaxime as microbateriologic examination revealed norcardia asteroids. He was eventually discharged home.Conclusion Nocardiasis is a rare cause of cerebral abcess in Morocco. Effective management includes early surgery and treatment with appropriate antibiotics

    Multinational Firms, Internal Capital Markets, and the Value of Global Diversification

    Get PDF
    Over the past 30 years, multinational firms’ investment grew four times faster than worldwide GDP. Yet the evidence on whether global diversification is valuable is inconclusive. This paper uses detailed foreign direct investment (FDI) data for 251 UK multinational firms and 4,676 subsidiaries for the period 1999–2005 to show that multinational firms exhibit, on average, a global diversification premium. I investigate this result and show that the premium is positively related to “winner-picking” transfers in internal capital markets, and more so for better-governed firms. The findings help explain why multinational firms’ investment and global diversification have significantly increased over the past three decades. </jats:p

    Institutional reform and FDI decision in transition economies: a qualitative study of Syria

    Get PDF
    The article considers the impact of institutional reform on the decision of foreign enterprises and foreign entrepreneurs to directly invest in the transition economy of Syria. It responds to the calls for more open research design that can go beyond the borders of the quantitative findings of previous econometric research by adopting a qualitative research strategy. The results reveal that institutional reforms enhanced Syria’s attractiveness to foreign direct investment. Institutional barriers proved to be less daunting to foreign investors whose backgrounds were culturally similar to that of Syria and/or already had experience in Syria or in a similar type of economy. The impact of background similarity and previous experience in similar contexts appeared to be less important when the foreign investor was a multinational enterprise than for individual entrepreneur. Moreover, these factors also appeared to be less important for large enterprises compared to small enterprises

    The ordinary city trap

    Get PDF
    The paper is a critique of a critique, it explains why the most salient and influential critiques of the neo-Marxist world city and global city concepts, made by those arguing to further postcolonialize urban studies through such suppositions that all cities are ‘ordinary’, are misguided. First, it is explained how the charges of economism and ethnocentrism against the world city and global city concepts are ignoratio elenchi: they do not even begin to address or critique their neo-Marxist argument that, across the difference and diversity of the world’s cities, a few major cities have the necessary economic specialization and therefore extraordinary function of commanding and controlling neoliberal globalization. Second, the error made by advocates of ordinary cities of supposing that world-systems analysis and the world city concept are forms of developmentalism is understood as the source for a wider postcolonial mistake of conflating the neo-Marxist world city and global city literatures with the very neoliberal practices toward urban development that they have long attempted to disclose and counter. Finally, the charges against the world city and global city concepts as paradigmatic, peripheralizing, and normative are also rebutted, not only to highlight how those critiques are consequentialist and dependent on the respective charges of economism, ethnocentrism, and developmentalism having veracity, but to demonstrate how an acceptance of the ordinary cities argument for an idiographic, provincial, nominalist, and comparative approach to urban studies, as an alternative to the two neo-Marxist concepts, is only to fall into the trap of making the mistake of confusing evidence of absence for absence of evidence

    Why Social Enterprises Are Asking to Be Multi-stakeholder and Deliberative: An Explanation around the Costs of Exclusion.

    Get PDF
    The study of multi-stakeholdership (and multi-stakeholder social enterprises in particular) is only at the start. Entrepreneurial choices which have emerged spontaneously, as well as the first legal frameworks approved in this direction, lack an adequate theoretical support. The debate itself is underdeveloped, as the existing understanding of organisations and their aims resist an inclusive, public interest view of enterprise. Our contribution aims at enriching the thin theoretical reflections on multi-stakeholdership, in a context where they are already established, i.e. that of social and personal services. The aim is to provide an economic justification on why the governance structure and decision-making praxis of the firm needs to account for multiple stakeholders. In particular with our analysis we want: a) to consider production and the role of firms in the context of the “public interest” which may or may not coincide with the non-profit objective; b) to ground the explanation of firm governance and processes upon the nature of production and the interconnections between demand and supply side; c) to explain that the costs associated with multi-stakeholder governance and deliberation in decision-making can increase internal efficiency and be “productive” since they lower internal costs and utilise resources that otherwise would go astray. The key insight of this work is that, differently from major interpretations, property costs should be compared with a more comprehensive range of costs, such as the social costs that emerge when the supply of social and personal services is insufficient or when the identification of aims and means is not shared amongst stakeholders. Our model highlights that when social costs derived from exclusion are high, even an enterprise with costly decisional processes, such as the multistakeholder, can be the most efficient solution amongst other possible alternatives

    Target company cross-border effects in acquisitions into the UK

    Get PDF
    We analyse the abnormal returns to target shareholders in crossborder and domestic acquisitions of UK companies. The crossborder effect during the bid month is small (0.84%), although crossborder targets gain significantly more than domestic targets during the months surrounding the bid. We find no evidence for the level of abnormal returns in crossborder acquisitions to be associated with market access or exchange rate effects, and only limited support for an international diversification effect. However, the crossborder effect appears to be associated with significant payment effects, and there is no significant residual crossborder effect once various bid characteristics are controlled for
    • 

    corecore