Toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) in the developing male Wistar(Han) rat II: chronic dosing causes developmental delay

We have investigated whether fetal exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD) causes defects in the male reproductive system of the rat, using chronically exposed rats to ensure continuous exposure of the fetus. 5-6 week old rats were exposed to control diet, or diet containing TCDD, to attain an average dose of 2.4, 8 and 46 ng TCDD kg-1 day-1 for twelve weeks, whereupon the rats were mated, and allowed to litter; rats were switched to control diet after parturition. Male offspring were allowed to develop until kills on PND70 (25 per group), or PND120 (all remaining animals). Offspring from the high dose group showed an increase in total litter loss, and the number of animals alive on post-natal day (PND) 4 in the high dose group was ~26% less than control. The high and medium dose offspring showed decreased weights at various ages. Balano-preputial separation was significantly delayed in all three dose groups, compared to control. There were no significant effects of maternal treatment when the offspring were subjected to a functional observational battery, or learning tests, with the exception that the high dose group showed a deficit in motor activity. 20 rats per group were mated to females, and there were no significant effects of maternal treatment on the fertility of these rats, nor on the F1 or F2 sex ratio. Sperm parameters at PND70 and 120 showed no significant effect of maternal treatment, with the exception that there was an increase in the proportion of abnormal sperm in the high dose group at PND70; this is associated with the developmental delay in puberty in this dose group. There were no remarkable findings of maternal treatment on organ weights, with the exception that testis weights were reduced by ~10% at PND70 (but not PND120), and although the experiment was sufficiently powered to detect small changes, ventral prostate weight was not reduced. There were no significant effects of maternal treatment upon histopathological comparison of high dose and control group organs. These data confirm that developmental exposure to TCDD shows no potent effect on adult sperm parameters or accessory sexual organs, but show that delay in BPS occurs after exposure to low doses of TCDD, and this is dependent upon whether TCDD is administered acutely or chronically

Secondary succession in an experimentally fragmented landscape: community patterns across space and time

Secondary succession reflects, at least in part, community assembly—the sequences of colonizations and extinctions. These processes in turn are expected to be sensitive to the size of the site undergoing assembly and its location relative to source pools. In this paper we describe patterns of succession over 18 years in an experimentally fragmented landscape created in eastern Kansas, USA, in 1984. The design of the experiment permits one to assess the influence of patch size and landscape position on successional dynamics. The general trajectory of succession follows that typical of succession in much of the eastern United States. In the initial years of the study, there was relatively little effect of patch size or distance to sources. Here we show that spatial effects in this system have become increasingly evident with time, as gauged both by repeated-measures ANOVA and ordination techniques. Woody plants have colonized more rapidly (per unit area) on large and nearby patches. Species richness at a local (within-quadrat) scale in general has increased, with slightly greater richness in large than in small patches later in the study. Temporal stability in community composition has generally been greater in large patches. Spatial heterogeneity in community composition has increased during succession, but with different patterns in large and small patches. This long-term experiment suggests that landscape structure influences many aspects of community structure and dynamics during succession, and that such effects become more pronounced with the passage of time

Development, Disease, and Regeneration of Tissues in the Dental-Craniofacial Complex

This article has no abstract

Forecasting the cytokine storm following systemic interleukin (IL)-2 administration

Extensive clinical experience has shown that systemic interleukin (IL)-2 administration can induce complete or partial regression of renal cell cancer (RCC) metastases in 15 to 20 % of patients. Since IL-2 has no direct anti-cancer effects, it is believed that cancer regression is mediated either by a direct modulation of immune cell effector functions or through the mediation of soluble factors released as a result of IL-2 administration. We previously observed that transcriptional and protein changes induced by systemic IL-2 administration affect predominantly mononuclear phagocytes with little effect, particularly within the tumor microenvironment, on T cell activation, localization and proliferation. It further appeared that mononuclear phagocyte activation could be best explained by the indirect mediation of a secondary release of cytokines by IL-2 responsive cells either in the circulation or in peripheral tissues. To better characterize the cytokine outburst that follows systemic IL-2 administration we followed the serum levels of 68 soluble factors in ten patients with RCC undergoing high dose (720,000 IU/kg intravenously every 8 hours) IL-2 therapy. Serum was collected before therapy, 3 hours after the 1(st )and 4(th )dose and assayed on a multiplexed protein array platform. This study demonstrated that 1) the serum concentration of more than half the soluble factors studied changed significantly during therapy; 2) changes became more dramatic with increasing doses; 3) subclasses of soluble factors displayed different kinetics and 4) cytokine patterns varied quantitatively among patients. This study shows that the cytokine storm that follows systemic IL-2 administration is complex and far-reaching inclusive of soluble factors with disparate, partly redundant and partly contrasting effects on immune function. Therefore comparing in parallel large number of soluble factors, it sets a comprehensive foundation for further elucidation of "cytokine storm" in larger patient pools. Based on this analysis, we propose a prospective collection of serum samples in a larger cohort of patients undergoing IL-2 administration with the purpose of discerning patterns predictive of clinical outcome and toxicity

Energy Access Scenarios to 2030 for the Power Sector in Sub-Saharan Africa

In order to reach a goal of universal access to modern energy services in Africa by 2030, consideration of various electricity sector pathways is required to help inform policy-makers and investors, and help guide power system design. To that end, and building on existing tools and analysis, we present several ‘high-level’, transparent, and economy-wide scenarios for the sub-Saharan African power sector to 2030. We construct these simple scenarios against the backdrop of historical trends and various interpretations of universal access. They are designed to provide the international community with an indication of the overall scale of the effort required. We find that most existing projections, using typical long-term forecasting methods for power planning, show roughly a threefold increase in installed generation capacity occurring by 2030, but more than a tenfold increase would likely be required to provide for full access – even at relatively modest levels of electricity consumption. This equates to approximately a 13% average annual growth rate, compared to a historical one (in the last two decades) of 1.7%.Energy Access, Power System Planning, Sub-Saharan Africa

Generic, Extensible, Configurable Push-Pull Framework for Large-Scale Science Missions

The push-pull framework was developed in hopes that an infrastructure would be created that could literally connect to any given remote site, and (given a set of restrictions) download files from that remote site based on those restrictions. The Cataloging and Archiving Service (CAS) has recently been re-architected and re-factored in its canonical services, including file management, workflow management, and resource management. Additionally, a generic CAS Crawling Framework was built based on motivation from Apache s open-source search engine project called Nutch. Nutch is an Apache effort to provide search engine services (akin to Google), including crawling, parsing, content analysis, and indexing. It has produced several stable software releases, and is currently used in production services at companies such as Yahoo, and at NASA's Planetary Data System. The CAS Crawling Framework supports many of the Nutch Crawler's generic services, including metadata extraction, crawling, and ingestion. However, one service that was not ported over from Nutch is a generic protocol layer service that allows the Nutch crawler to obtain content using protocol plug-ins that download content using implementations of remote protocols, such as HTTP, FTP, WinNT file system, HTTPS, etc. Such a generic protocol layer would greatly aid in the CAS Crawling Framework, as the layer would allow the framework to generically obtain content (i.e., data products) from remote sites using protocols such as FTP and others. Augmented with this capability, the Orbiting Carbon Observatory (OCO) and NPP (NPOESS Preparatory Project) Sounder PEATE (Product Evaluation and Analysis Tools Elements) would be provided with an infrastructure to support generic FTP-based pull access to remote data products, obviating the need for any specialized software outside of the context of their existing process control systems. This extensible configurable framework was created in Java, and allows the use of different underlying communication middleware (at present, both XMLRPC, and RMI). In addition, the framework is entirely suitable in a multi-mission environment and is supporting both NPP Sounder PEATE and the OCO Mission. Both systems involve tasks such as high-throughput job processing, terabyte-scale data management, and science computing facilities. NPP Sounder PEATE is already using the push-pull framework to accept hundreds of gigabytes of IASI (infrared atmospheric sounding interferometer) data, and is in preparation to accept CRIMS (Cross-track Infrared Microwave Sounding Suite) data. OCO will leverage the framework to download MODIS, CloudSat, and other ancillary data products for use in the high-performance Level 2 Science Algorithm. The National Cancer Institute is also evaluating the framework for use in sharing and disseminating cancer research data through its Early Detection Research Network (EDRN)