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Landscape-scale alterations that accompany urbanization may negatively affect the population structure of wildlife species such as freshwater turtles. Changes to nesting sites and higher mortality rates due to vehicular collisions and increased predator populations may particularly affect immature turtles and mature female turtles. We hypothesized that the proportions of adult female and immature turtles in a population will negatively correlate with landscape urbanization. As a collaborative effort of the Ecological Research as Education Network (EREN), we sampled freshwater turtle populations in 11 states across the central and eastern United States. Contrary to expectations, we found a significant positive relationship between proportions of mature female painted turtles (Chrysemys picta) and urbanization. We did not detect a relationship between urbanization and proportions of immature turtles. Urbanization may alter the thermal environment of nesting sites such that more females are produced as urbanization increases. Our approach of creating a collaborative network of scientists and students at undergraduate institutions proved valuable in terms of testing our hypothesis over a large spatial scale while also allowing students to gain hands-on experience in conservation science.

A new phytochemical study of the indigenous Brazilian species Hippeastrum papilio is reported herein. Three novel Amaryllidaceae alkaloids were isolated, including hippapiline (1), papiline (2), and 3-O-demethyl-3-O-(3-hydroxybutanoyl)haemanthamine (3). Their structures were determined by physical and spectroscopic methods. In addition, the known alkaloids, haemanthamine (4), galanthamine (5), narwedine (6), 11β-hydroxygalanthamine (7), apogalanthamine (8), and 9-O-demethyllycosinine B (9) were identified. The unusual cis-B/C-ring fusion for the new homolycorine representative hippapiline was ratified by NMR and CD spectroscopy. Fil: Guo, Ying. University of Barcelona. Faculty of Pharmacy. Department of Natural Products, Plant Biology and Soil Science; España Fil: Andrade, Jean P. de. University of Barcelona. Faculty of Pharmacy. Department of Natural Products, Plant Biology and Soil Science; España. Universidade Federal do Espírito Santo; Brasil Fil: Pigni, Natalia Belen. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba. Instituto de Ciencia y Tecnología de Alimentos Córdoba. Universidad Nacional de Córdoba. Facultad de Ciencias Químicas. Instituto de Ciencia y Tecnología de Alimentos Córdoba; Argentina. University of Barcelona. Faculty of Pharmacy. Department of Natural Products, Plant Biology and Soil Science; España Fil: Torras-Claveria, Laura. University of Barcelona. Faculty of Pharmacy. Department of Natural Products, Plant Biology and Soil Science; España. Universidade Federal do Espírito Santo; Brasil Fil: Tallini, Luciana R.. University of Barcelona. Faculty of Pharmacy. Department of Natural Products, Plant Biology and Soil Science; España Fil: Souza Borges, Warley de. Universidade Federal do Espírito Santo; Brasil Fil: Viladomat, Francesc. University of Barcelona. Faculty of Pharmacy. Department of Natural Products, Plant Biology and Soil Science; España Fil: Nair, Jerald J.. University of Barcelona. Faculty of Pharmacy. Department of Natural Products, Plant Biology and Soil Science; España Fil: Zuanazzi, José A. S.. Universidade Federal do Rio Grande do Sul; Brasil Fil: Bastida, Jaume. University of Barcelona. Faculty of Pharmacy. Department of Natural Products, Plant Biology and Soil Science; España

Question To what extent are species, including native and non-native species, influencing one another's distribution and abundance in the herb layer of a Minnesota oak woodland? Location Oak woodland succeeding into a more mesic forest, on bluffland of the Mississippi River, east-central Minnesota. Methods We collected plant composition and species cover data in 182 1.0 × 0.5 m quadrats regularly spaced on a 6-ha study grid in the oak woodland. We also recorded slope, slope position, aspect, elevation and photosynthetically active radiation (PAR) at each quadrat. Results Presence and abundance of other plant species, topographic variables and light availability explained only a small portion of the variation (5–19%) in the distribution and abundance of individual species. The most common strongest predictor of cover for the ten most common species was species richness, with the association being positive. The non-native species, garlic mustard (Alliaria petiolata) exhibited the strongest positive association with species richness. Only one of the 45 pair-wise comparisons of the ten species resulted in a negative relationship between the species. Abundance and distribution of two species were associated with topographic features, but this accounted for much less of the variation in abundance than did species richness. Conclusion We found little evidence that competition or any other interactions among common herb layer species, including the non-native Alliaria petiolata, play an important role in determining the abundance and the distribution of herb layer species in this oak woodland. Topographic factors may explain a small amount of the distribution and abundance patterns of a few species. But, for the most part, species are more likely to be present when other species are present, suggesting that they are simply establishing in microsites favourable to plants in general.

The magnesium chloride catalyzed anti-aldol reaction of phenyl acetate derived oxazolidinones proceeds readily with enolizable L-threose derivative 8 to provide anti-aldol adducts in high yields and with very high diastereoselectivities. The reaction is also efficient with aromatic aldehydes and provides slightly lower diastereoselectivities. This extension

A catalyst system consisting of a chromium source, a 2,6-disubstituted phenol and an aromatic ether solvent, on activation with triethylaluminium, is active and selective for the trimerisation of ethylene to form 1-hexene. The aromatic ether appears to play a role as both solvent and reagent and is pivotal in ensuring both the good activity of the system as well as selectivity to the desired product, 1-hexene.

Aim of this study was to develop and characterize an applicable in vivo model to investigate angiogenesis of human gliomas. An established glioblastoma spheroid model was used to investigate the neovascularization of a standardized avascular solid tumor mass. Spheroids of two human glioma cell lines were labeled with an in vivo fluorescent dye. Single spheroids were implanted into the cortex of athymic rats. After 1, 3, 7, 14, and 21 days, brain sections containing the spheroid were immunostained for endothelial cells or vascular endothelial growth factor (VEGF). The dye-stained glioma spheroid and the endothelial cells were visualized by confocal microscopy. Two distinct mechanisms of tumor vascularization could be observed. (1) "Classical" angiogenesis with new vessels sprouting from existing host vessels into the spheroid was seen. (2) Individual endothelial cells were found to migrate towards and into the center of the spheroid where they coalesced to form new vessels. This process occurred as early as 24 hr after spheroid implantation. Spheroid vascularization was accompanied by an increase of VEGF expression, which peaked 7 days after implantation and returned to normal patterns by 14-21 days. Besides the "classical" angiogenesis by angiogenic blood vessels, the recruitment of individual endothelial cells seems to be an additional mechanism in early glioma vascularization. Our model proves to be a reliable, reproducible system to study in vivo angiogenesis of human gliomas.

Cell adhesion receptors of the integrin superfamily, CD44, and adhesion receptors of the immunoglobulin superfamily are expressed by high-grade astrocytic tumors of the central nervous system. These receptors are critical for the invasion of these tumors in the nervous system. Glioma cells utilize these receptors to adhere to and migrate along the components of the extracellular matrix, which is uniquely distributed and regulated within the brain and the spinal cord. For this reason, glioma cell invasion into the adjacent brain tissue is dependent on the interaction of glioma cells with the extracellular matrix. The receptor-ECM component interaction is discussed, focusing on the role of cell adhesion molecules of the integrin family and CD44 in glioma cell adhesion and invasion.

The following series of experiments explores the post-xenografting differentiation of a naturally occurring, non-neuronal cell cultured from the leptomeninges of an 84-year-old woman. In culture, flat process-bearing human cells from the leptomeninges were positive for GFAP and 200 kDa neurofilament protein (negative for 68, 160 kDa neurofilament protein). The C3 spinal cord was exposed in 30 adult athymic rats. The hindlimb dorsal columns were transected at C3 and the nerve fibers aspirated to form a pocket, into which 10(6) fast blue-labeled, human leptomeningeal-derived cells were placed. The C3 spinal cord was studied immunohistochemically over 60 days. Three days later the dorsal horn contained fast blue-GFAP-positive astrocyte-like cells that were negative for neurofilament protein. By 7 days, large, process-bearing, fast blue-GFAP-positive (neurofilament protein-negative), astrocyte-like cells joined the native astrocytes of the pia-glia membrane and were in the gray matter of the spinal cord. Some of these astrocyte-like cells were also positive for the human specific histocompatibility complex, HLADR. These data extend the age, species and tissue of origin for pluripotential cells for CNS transplantation.

Astrocytes appear to be excluded from blood vessels. In order to test this observation, pial blood vessels were seeded upon cultures of purified E14 fetal astrocytes. One to seven days later co-cultures were immunohistochemically stained for laminin and fibronectin. Confocal microscopy revealed that laminin-positive cultured astrocytes migrated from the coverslip to and on to the surface of the blood vessels. The fetal astrocytes migrated along the basement membrane but did not enter the blood vessel. Viable (live) basement membrane is a barrier to astrocyte intravasation and is a pathway for astrocyte migration. Published by Elsevier Science Ltd.

I. INTRODUCTION Public awareness about the health and environmental consequences of agricultural chemical use has continued to grow following publication of Rachael Carson's Silent Spring in 1962. That concern led policymakers to form the Environmental Protection Agency (EPA) in 1972 and to enact legislation such as the Clean Water Act and the Federal Insecticide, Fungicide, and Rodenticide Act. However, agricultural nonpoint-source pollution--that is, water pollution from runoff of fertilizers, pesticides, and agricultural land sediment--remains largely unregulated.(1) Solving a number of important remaining water pollution problems requires reducing agricultural nonpoint pollution. However, the best way to achieve that reduction is unclear. Agricultural nonpoint pollution policy traditionally has relied on voluntary programs such as those administered by the USDA Soil Conservation Service. These programs often couple technical assistance with a subsidy covering a portion of the recommended practice's cost. Voluntary programs are popular with farmers. However, conventional wisdom suggests that farmers would be unlikely to adopt voluntarily pollution-reducing practices without a subsidy covering full costs of the practice plus any revenue loss. Abbreviations EPA: Environmental Protection Agency PMB: Private Marginal Benefit PMC: Private Marginal Cost WTA: Willingness-to-accept Alternatives to voluntary programs include regulation, increased farmer liability for water quality damages, and taxes on pesticide and fertilizer purchases. Policymakers commonly regulate pesticides but rarely regulate fertilizers. (Nebraska, for example, does restrict fertilizer use in areas that are susceptible to nitrate contamination of groundwater.) EPA, through its pesticide registration process, may limit pesticide use to particular crops or particular regions. EPA also may restrict farm laborers from entering fields just after spraying. The Food and Drug Administration sets maximum allowable tolerances for pesticide residues on foods. EPA may ban use of a pesticide that constitutes an undue health or environmental threat by cancelling its registration. Regulation is a reasonably effective way of dealing with toxic substances such as pesticides. However, regulation can be a cumbersome and expensive alternative for non-toxic substances that cause environmental damages when present in excessive amounts. With some exceptions, sediment pollution and fertilizer pollution fall into this category. Liability is another important alternative policy. Although certain states, such as Connecticut, use limited farmer liability for groundwater pollution, liability also is problematic. Lawsuits can produce "highly unsystematic levels of compensation, distorted incentives, and high transactions costs" (Menell, 1991). Economists often recommend taxes on fertilizer and pesticide purchases since such taxes would reduce the use of polluting inputs. However, studies show that to have a noticeable impact on nitrogen fertilizer usage, nitrogen taxes would have to be over 100 percent (Johnson et al., 1991). Voluntary programs coupled with subsidies are not free of shortcomings, but in certain cases voluntary programs may be more effective than one might expect because the farming business possesses a unique structure. In farming, the owner/operator and the owner/operator's family generally reside on the farm site. Industrial or "corporate" farms owned by nonresident shareholders are uncommon. In 1987, 99.2 percent of all farms were sole proprietorships, partnerships, or family held corporations (U.S. Department of Commerce, 1989). Therefore, the owners and decision makers on a farm may bear a portion of the pollution costs of their production decisions and thus have an incentive to reduce that pollution.(2) For example, pesticides and fertilizers can leach into the farmer's own well water and endanger family health in addition to polluting water off the farm, such as the community water supply. …

The assessment of environmental quality problems and the design and economic evaluation of alternative federal, state, and local policy strategies to address environmental issues require complex analyses which must address the underlying physical, biological, social, and economic processes. The study of environmental problems is thus inherently multidisciplinary and should involve the physical, biological, and social sciences. Unfortunately, the multidisciplinary nature of environmental issues has caused problems with the quality and general availability of the data necessary for appropriate analyses. While data have been collected in many areas to address discipline-specific problems, there has been little regard for the eventual need to coordinate analyses across disciplinary lines. As Portney points out, this lack of coordination in data collection is reflected in the often Bal

Cultured C6 glioma cells were prelabeled with the plant lectin Phaseolus vulgaris leuco-agglutinin (PHAL) and grafted as a cell suspension (10(6) cells in 5.0 microliters) into freshly made cortical implantation pockets in adult host rats. Animals were killed 1-21 days post-implantation (DPI). The brains were removed, dehydrated, embedded in paraffin and sectioned at 8 microns. Paraffin sections were processed for light level immunofluorescent double labeling for PHAL, a marker for graft derived cells, and glial fibrillary acidic protein (GFAP), a specific marker for C6 glioma cells and astrocytes. Cells positive for both PHAL and GFAP were graft-derived C6 cells. By 7 DPI a large mass developed which extended above the surface of the brain and invaded (displacement of host tissue by a cell mass) the host parenchyma. This mass increased in size over the next 14 days. The invading tumor mass contained double labeled cells at all time periods examined. In addition to the invasion process, grafted C6 cells spread through the host parenchyma by migration (movement of single cells). Individual graft-derived C6 (GFAP/PHAL positive) cells migrated into host cortex surrounding the implantation pocket, corpus callosum ventral to the implantation pocket, ipsilateral internal capsule and bilaterally in the habenula.

Application of phosphonium salt ionic liquids in the carbonylation of aryl and vinyl halides is presented. Anionic effects were uncovered with the bromide ionic liquid emerging as the superior media. Acid bromide intermediates were detected in control experiments providing an extended view on the overall catalytic cycle involved. Solvent-free product isolation and recycling of the ionic liquid containing active Pd-catalyst are also demonstrated.