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Selected AbstractsRelB/p50 regulates CCL19 production, but fails to promote human DC maturationEUROPEAN JOURNAL OF IMMUNOLOGY, Issue 8 2009Chiara Gasparini Abstract DC, when fully matured are the APC best able to activate naïve T cells. Recently, we demonstrated using adenoviruses overexpressing I,B, and proteosome inhibitors that NF-,B is involved in DC activation, but the role of the individual subunits is still not clear. We investigated the role of the NF-,B subunits RelB and p50 in human DC activation using adenoviral vectors expressing RelB or p50. Nuclear RelB, in the form of RelB/p50, was active only in DC infected with both viruses, this induced the production of the soluble homeostatic chemokine CCL19, but not other homeostatic chemokines, particularly in LPS-matured DC. However, RelB/p50 did not affect the expression of costimulatory and antigen-presenting molecules, and increased the allogeneic mixed lymphocyte reaction only in LPS-matured DC. This enhanced mixed lymphocyte reaction is most likely due to enhanced CCL19 production, which sustains the interaction between mature DC and naïve T cells. In conclusion, we demonstrated that RelB/p50 was active only in DC expressing both RelB and p50, and induced CCL19 production, but not DC maturation. [source] Bird densities are associated with household densitiesGLOBAL CHANGE BIOLOGY, Issue 8 2007JAMIE TRATALOS Abstract Increasing housing density is an important component of global land transformation, with major impacts on patterns of biodiversity. However, while there have been many studies of the changes in biodiversity across rural,urban gradients, which are influenced in large part by housing densities, how biodiversity changes across the full range of regional variation in housing density remains poorly understood. Here, we explore these relationships for the richness and abundance of breeding birds across Britain. Total richness, and that of 27 urban indicator species, increased from low to moderate household densities and then declined at greater household densities. The richness of all species increased initially faster with household density than did that of the urban indicator species, but nonurban indicator species richness declined consistently after peaking at a very low housing density. Avian abundance showed a rather different pattern. Total abundance and that summed across all urban indicator species increased over a wide range of household densities, and declined only at the highest household densities. The abundance of individual urban indicator species generally exhibited a hump-shaped relationship with housing density. While there was marked intraspecific variation in the form of such relationships, almost invariably avian abundance declined at housing densities below that at which the UK government requires new developments to be built. Our data highlight the difficulties of maintaining biodiversity while minimising land take for new development. High-density housing developments are associated with declines in many of those species otherwise best able to exploit urban environments, and those components of native biodiversity with which human populations are often most familiar. [source] ESTIMATING THE TAX BENEFITS OF DEBTJOURNAL OF APPLIED CORPORATE FINANCE, Issue 1 2001John Graham The standard approach to valuing interest tax shields assumes that full tax benefits are realized on every dollar of interest deduction in every scenario. The approach presented in this paper takes account of the possibility that interest tax shields cannot be used in some scenarios, in part because of variations in the firm's profitability. Because of the dynamic nature of the tax code (e.g., tax-loss carrybacks and carryforwards), it is necessary to consider past and future taxable income when estimating today's effective marginal tax rate. The paper uses a series of numerical examples to show that (1) the incremental value of an extra dollar of interest deduction is equal to the marginal tax rate appropriate for that dollar; and (2) a firm's effective marginal tax rate (and therefore the marginal benefit of incremental interest deductions) can actually decline as the firm takes on additional debt. Based on marginal benefit functions for thousands of firms from 1980,1999, the author concludes that the tax benefits of debt averaged approximately 10% of firm value during the 1980s, while declining to around 8% in the 1990s. By taking maximum advantage of the interest tax shield, the average firm could have increased its value by approximately 15% over the 1980s and 1990s, suggesting that the consequences of being underlevered are significant. Surprisingly, many of the companies that appear best able to service debt (i.e., those with the lowest apparent costs of debt) use the least amount of debt, on average. Treasurers and CFOs should critically reevaluate their companies' debt policies and consider the benefits of additional leverage, even if taking on more debt causes their credit ratings to slip a notch. [source] Attacking Poverty,a strategic dilemma for the World BankJOURNAL OF INTERNATIONAL DEVELOPMENT, Issue 3 2001Michael Hubbard Attacking Poverty has attracted more than the usual interest in World Development Reports mainly because it reflects the dilemma in future strategy for the World Bank. Its basis in a widely welcomed consultation with the poor, its transparent process and new conceptual framework contrast with limited development of the new themes , equality, security, empowerment of the poor , and of issues to do with aid: resources and rights. Contributors to this special issue discuss the dilemma reflected in Attacking Poverty from a number of angles: critical self-awareness by World Bank, promoting equality, shifting from the Washington Consensus, limits to the Bank's role, and enabling collective action by the poor. Other contributions discuss how the analysis in Attacking Poverty should be strengthened: inclusion of urban poverty and urbanisation's role in political development, promoting informal means of reducing vulnerability, and investigation of the long term consequences of the HIV/AIDS pandemic. Priorities for the next poverty-focused World Development Report (2010?) should include a more disaggregated and complete view of who is poor, why and where, and analysis of progress in political development. The World Bank may be best able to contribute to political development by extending to the subnational and public services level its main achievement of recent decades: the gathering, analysis and dissemination of comparative development data, to help move the focus of politics towards improving services and living standards. Copyright © 2001 John Wiley & Sons, Ltd. [source] A Quantum-Mechanical QSAR Model to Predict the Refractive Index of Polymer MatricesMOLECULAR INFORMATICS, Issue 10 2006Andrew Abstract Refractive index (RI) is an important optical property for polymer matrices, especially when the color or tint of the cured material is of interest. This is certainly the case for dental restorative applications. In this work, results are presented for a quantitative,structure activity relationship derived from relevant semiempirical quantum mechanical information. This model predicts the RI for a wide variety of polymer matrices using representative structures of polymers, including resin components of several currently used dental restorative materials. The AM1 semiempirical method was used for calculations due to its speed and general reliability. Several structural subunits of the polymer chains were used for the QSAR analysis, but dimer moieties produced the best results for some 60 polymers. The final QSAR model was composed of a multilinear equation that featured the highest occupied molecular orbital , the lowest unoccupied molecular orbital gap and a polarizability index as the two descriptors best able to account for the variation in the data. The final model had R2=0.963, R2cv=0.959, F=740, and s2=0.0002. Other quality indicators for the correlation and the individual descriptors were within acceptable limits. The presence of electronically related descriptors is encouraging, as these are conceptually tied to the phenomenon of RI. The difference between a theoretically predicted value for poly(propylene oxide) and its monomer was 0.04, as compared to 0.09 from experimental data. [source] Liposomes in investigative dermatologyPHOTODERMATOLOGY, PHOTOIMMUNOLOGY & PHOTOMEDICINE, Issue 5 2001Daniel B. Yarosh Liposomes are microscopic spheres, usually composed of amphiphilic phospholipids. They may be useful without skin penetration if they simply protect or sequester compounds that would otherwise be unstable in the formulation. Liposomes that remain on the skin surface are useful as light-absorbers, agents to deliver color or sunscreens, or as depots for timed-release. Liposomes that penetrate the stratum corneum have the potential to interact with living tissue. Topically applied liposomes can either mix with the stratum corneum lipid matrix or penetrate the stratum corneum by exploiting the lipid-water interface of the intercellular matrix. There are at least four major routes of entry into the skin: pores, hair follicles, columnular spaces and the lipid:water matrix between squames. A major force driving liposome penetration is the water gradient, and flexible liposomes are best able to exploit these delivery opportunities. Some liposomes release their contents extracellularly. Topical application of photosensitizers may be enhanced by encapsulation in liposomes. Higher and longer-lasting drug concentrations may be produced in localized areas of skin, particularly at disease sites where the stratum corneum and the skin barrier function are disrupted. The liposome membrane should be designed to capture lipophilic drugs in the membrane or hydrophilic drugs in the interior. Other types of liposomes can be engineered to be taken up by cells. Once inside cells, the lysosomal sac and clatherin-coated pit are the dead-end destinations for liposomes unless an escape path has been engineered into the liposome. A novel method has been developed to allow delivery into cells of the skin, by escape from the lysosomal sac. These liposomes have been used to topical deliver active DNA repair enzymes from liposomes into epidermal cells and to enhance DNA repair of UV-irradiated skin. From these studies a tremendous amount has been learned about the relationship of DNA damage and skin cancer. Both mutations and immunosuppression appear to be essential to skin cancer and both are induced by DNA damage. DNA damage produces immediate effects by inducing the expression of cytokines, which means that DNA damage can induce signaling in neighboring, undamaged cells. The repair of only a fraction of the DNA damage has a disproportionate effect on the biological responses, clearly demonstrating that not all DNA damage is equivalent. This technology demonstrates that biologically active proteins can be delivered into the cells of skin, and opens up a new field of correcting or enhancing skin cell metabolism to improve human health. [source] Breastfeeding structure as a test of parental investment theory in Papua New Guinea,AMERICAN JOURNAL OF HUMAN BIOLOGY, Issue 5 2009David P. Tracer Evolutionary parental investment theory predicts that parents invest preferentially in offspring best able to translate investments into fitness payoffs. It has also been proposed that where the reproductive prospects of offspring are directly correlated with parental investment and variance in fertility is higher for males than females, parents in better condition should bias investment toward males while those in poorer condition should bias investment toward females. Lactation is arguably among the costliest forms of investment expended by mothers and is thus expected to be allocated in ways consistent with fitness payoffs. Quantitative data collected among 110 Papua New Guinean mother-infant pairs during 470 h of focal follows on nursing frequency and duration and responses to infant demands by maternal and offspring characteristics are presented to provide empirically-based descriptions of infant care and tests of evolutionary parental investment theory. Results indicate that mothers show very high levels of investment in offspring. However, although breastfeeding in developing countries is often characterized as on-demand, fussing and crying by infants were only attended to with breastfeeding about 30% of the time. Contrary to expectations of parental investment theory that parents should invest less in poorer quality offspring, mothers increased investment in offspring in poorer condition. The expectation that mothers in better condition would bias investment toward male offspring was also not supported; better nourished mothers biased investment toward female offspring. This study illustrates how infant feeding data may be used for testing larger evolutionary questions such as those derived from parental investment theory. Am. J. Hum. Biol. 2009. © 2009 Wiley-Liss, Inc. [source] Inconsistent Evidence: Analysis of Six National Guidelines for Vaginal Birth After Cesarean SectionBIRTH, Issue 1 2010GradDipClinEpi, Maralyn Foureur BA Abstract:, Background:, Guidelines are increasingly used to direct clinical practice, with the expectation that they improve clinical outcomes and minimize health care expenditure. Several national guidelines for vaginal birth after cesarean section (VBAC) have been released or updated recently, and their range has created dilemmas for clinicians and women. The purpose of this study was to summarize the recommendations of existing guidelines and assess their quality using a standardized and validated instrument to determine which guidelines, if any, are best able to guide clinical practice. Methods:, English language guidelines on VBAC were purposively selected from national and professional organizations in the United Kingdom, United States, Canada, New Zealand, and Australia. The Appraisal of Guidelines for Research and Evaluation (AGREE) instrument was applied to each guideline, and each was analyzed to determine the range and level of evidence on which it was based and the recommendations made. Results:, Six guidelines published or updated between 2004 and 2007 were examined. Only two of the six guidelines scored well overall using the AGREE instrument, and the evidence used demonstrated great variety. Most guidelines cited expert opinion and consensus as evidence for some recommendations. Reported success rates for VBAC ranged from 30 to 85 percent, and reported rates of uterine rupture ranged from 0 to 2.8 percent. Conclusions:, VBAC guidelines are characterized by quasi-experimental evidence and consensus-based recommendations, which lead to wide variability in recommendations and undermine their usefulness in clinical practice. (BIRTH 37:1 March 2010) [source] | |||||||||||||