In-situ impact of natural sunlight and tidal action on the composition and toxicity of sediment-associated organic pollutants

Organic pollutants pose a haz.ard to living resources of the Chesapeake Bay and elsewhere. P AHs and other compounds present in creosote are major contaminants of concern. Polychlorinated terphenyls (PCTs), PCB-like compounds, have also been detected in high concentrations in sediments from several areas. Fates of these toxic compounds in-situ are poorly understood. In this study the impacts of physical processes operating in a tidal creek on the fate of creosote constituents (i.e. P AHs and heterocyclics) and PCTs were examined. Two representative sediments ( a coarse/low organic carbon (LOC) and a fine, high organic carbon (HOC)) were fortified with creosote and PCT formulations 5432 and 5460. Pollutant fortified sediments and unspiked controls were placed in the: 1) subtidal; 2) intertidal; and 3) epitidal zones of a southeastern VA tidal creek and permitted to weather under ambient conditions for 33 days. Sealed, UV-protected and unspiked treatments were also deployed. Water extractable fractions (WEFs) generated from these sediments were chemically characterized and tested for acute toxicity using the bacterial luminescence assay Microtox. WEFs were examined, as the water solubilized components have been found responsible for the majority of toxic effects associated with contaminated sediments. Examination of WEF composition also provides valuable information on contaminant behavior and fate

Two Projects Informed by Work on Glucosepane

Part 1: Having developed a reaction to synthesize the protein-sugar crosslink glucosepane, we sought to apply our lessons to the synthesis of structurally similar molecules. Marine alkaloids containing a diaminoimidazole-derived core possess intriguing chemical structures and have displayed promising antimicrobial activity in preliminary screens. However, these compounds generally contain densely functionalized multicyclic cores and relatively large numbers of nitrogen atoms. For these reasons, they have proven difficult to synthesize. In this work, we report a novel total synthesis of the marine alkaloid (±)-dibromoagelaspongin. Our key intermediate is a 2,5-diaminoisoimidazole accessed in one step from a suitably protected guanylhydrazine and an amidoketone through a [3,3]-sigmatropic rearrangement-elimination. The incorporation of the densely functionalized core in a single step enabled a dramatically simplified synthetic route, and the natural product was obtained in fewer than half the number of steps of the sole prior published route in excellent overall yield.Part 2: It is well known that glucosepane, which is associated with many diseases and aging, forms on opposing strands of collagen subunits that are comprised of three intertwined polypeptides. Because glucosepane is a post-translational modification that forms very slowly in vivo, no method to express glucosepane-crosslinked collagen exists, and isolation of the crosslink through tissue digestion has yielded few fruits. Accordingly, a need for model systems exists. Since optical tweezers often find application in characterizing large molecules—including expressed tropocollagen molecules—and chemical changes to them that are too fast or too slow for an ensemble average to be effective, they stand to play a major role in the characterization of synthetic collagen-mimicking peptides bearing an artificially installed crosslink. We believe the data presented herein constitute a significant advance toward what to the best of our knowledge would be the first force-extension data generated on an optical tweezer from a synthetic collagen-mimicking peptide

Alterations in land surface-atmosphere processes resulting from the 1988 Greater Yellowstone Area fires.

Meteorological observations for the 10-year period 1984 to 1993 have been collected from 178 stations within the GYA, quality assured, and spatially and temporally interpolated to produce gridded data suitable for model input. These data comprise 8-km resolution hourly values of seven meteorological variables: near-surface air temperature, relative humidity, precipitation, wind speed, atmospheric pressure, and downwelling solar and longwave radiation.New algorithms for modeling of snow and frozen soil have been implemented in the Simulator for Hydrology and Energy Exchange at the Land Surface (SHEELS) model. These added capabilities, necessary for using the SHEELS model in the GYA, allow for the hydrologic, thermal, and albedo effects of snow cover and frozen soil to be realized in model output.Substantial alterations of the latent and sensible heat fluxes were found to result from the removal of vegetation by the 1988 fires. Specifically, latent heat flux was decreased and sensible heat flux increased in the burn area. Furthermore, these effects also were seen downwind of the burn area, indicating that regional climate may have been affected by the fires. Soil moisture was not substantially affected by the fire-induced vegetation changes, however.The SHEELS model was then used to examine surface energy budget and soil moisture variables before and after the 1988 fires. Four datasets of these variables were produced for each of three regions within the GYA: a burn area consisting of fire-affected regions, an area upwind of the burn area, and an area downwind from the burn area. The four datasets provide a basis for differentiation among possible causes of any observed alterations in surface energy budget or soil moisture variables and result from varying the vegetation or meteorological model forcing.During the late summer of 1988, wildland fires in Yellowstone National Park and the surrounding Greater Yellowstone Area (GYA) burned approximately 570,000 ha. The dramatic alteration in land cover resulting from these fires coupled with the availability of surface and satellite data necessary for modeling land surface-atmosphere processes provides an ideal opportunity to study the effects of fire-induced vegetation changes on surface energy budget variables and soil moisture

Wordsworth\u27s Mother Tongue: Identification, Separation, and Recognition.

This psychoanalytic study complicates prevailing notions about William Wordsworth\u27s representations of mothers. Wordsworth does not invariably conflate mothers with Nature or consistently construct women as silent objects of male quest. Rather, he explores a variety of mothers\u27 voices, often associating them with language acquisition and poetic composition. In early work he acknowledges mothers\u27 significance directly and creates more vocal mothers, while in later work and revisions he often conceals mothers\u27 significance and depicts more object-like mothers. In the 1805 version of book two of The Prelude, Wordsworth recalls himself as a blessed babe who recognizes his mother as a separate subject. From this relationship, the babe derives the creative and receptive powers of the poetic spirit and expands the development of poetic powers to the relationship between child and a Nature personified as a mother. In the 1850 version of book two, however, he objectifies the mother and Nature and reduces their explicit significance on the poetic spirit. The dynamic of similitude in dissimilitude, which Wordsworth discusses in The Preface to Lyrical Ballads and which structures much of his poetic theory, is rooted in the mother-child experience of recognition described in The Prelude. Wordsworth splits off mother associations in later revisions, but an ungendered maternal dynamic remains as the matrix for his definition of the Poet. In Her Eyes Are Wild, Wordsworth experiments with a mother\u27s voice to depict a filial relationship. He demonstrates the consequences of a mother\u27s over-identification with her child and implies what might happen when poets over-identify with their subjects. In later editions the balladeer finds a more stable voice by identifying with the mother and maintaining self-awareness; however, the mother never achieves such balance. In The Sailor\u27s Mother, The Emigrant Mother, The Affliction of Margaret, The Force of Prayer, and The Widow on Windermere, Wordsworth represents mothers physically separated from their children by distance or death and explores how they resist separation through mourning. The way these mothers articulate their desires often resembles the way poets construct poems: both strive to recollect persons or re-order experiences to accept separation and maintain a sense of connection

Accumulation of toxic organic pollutants in the blue crab Callinectes sapidus (aromatic hydrocarbons, gas chromatography, polychlorinated biphenyls, Virginia)

Levels of toxic organic pollutants (TOP) were examined in the blue crabs, Callinectes sapidus, of Virginia waters. Alkyl substituted polynuclear aromatic hydrocarbons (ASPAH), thought derived from weathered petroleum, were the most common organic pollutants present. Unsubstituted aromatics, heterosubstituted aromatics, polychlorinated biphenyls (PCB), and DDT metabolites were also detected by the analytical procedure employed. Highest levels of ASPAH were found in crabs from the heavily industrialized Hampton Roads area of the James River. Lower concentrations were detected in crabs from the Pocomoke Sound, the upper James and the Rappahannock River sampling sites. PCB levels were elevated in samples taken from both James River stations. Levels of TOP were generally higher in crabs sampled in June than in September of 1981. Concentrations of pollutants in the tissues and tissue lipid content were correlated. Highest levels of both were detected in the hepatopancreas, followed by egg, ovary and muscle. TOP levels in field samples and in-vivo biotransformation of the model compound benzo(a)pyrene (B(a)P) in the hepatopancreas, during in-laboratory experiments, suggested that differences may exist in the uptake and elimination of pollutants as a function of the sex and maturity of the crabs. It appeared that the metabolism of aromatic hydrocarbons varied with the molt stage of the crabs. A variety of polar metabolites of tritium labeled B(a)P were detected in the hepatopancreas of blue crabs, when examined by normal and reverse phase high performance liquid chromatography. In conclusion, to accurately assess the levels and effects of TOP in biota from the field, several factors must be considered. Among these are the species and tissues examined, the sex, maturity and condition of the individuals selected for analysis, and the location and season of sampling

Bioavailability of Organic Pollutants to Aquatic Organisms

Settlement of the Chesapeake Bay region began in earnest in the early 17th century. The native American population and early colonists were impressed by the abundance of fish and shellfish and located their population centers to take advantage of these and other natu!al resources. Introduction of wastes into the bay was coincident with this settlement. As the human population increased, so did the pressure on the ecological system. In the 20th century significant quantities of synthetic chemicals began to be introduced, many of which were toxic and nonbiodegradable [Faust and Hunter 1971]. Today the areas surrounding the bay are experiencing unprecedented development; introduction of toxic organic pollutants has correspondingly increased. Water quality and the abundance of many aquatic organisms have suffered accordingly [O\u27Connor and Huggett 1988].https://scholarworks.wm.edu/vimsbooks/1177/thumbnail.jp