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  • 1
    Electronic Resource
    Electronic Resource
    A comparison of geochemical information obtained from two fluvial bed sediment fractions (2000)
    Springer
    Environmental geology 39 (2000), S. 330-341 
    Details
    ISSN: 1432-0495
    Keywords: Key words Fluvial bed sediments ; Contamination indices ; Grain-size partitioning ; Non-parametric statistics ; Manoa Stream
    Source: Springer Online Journal Archives 1860-2000
    Topics: Geosciences
    Notes: Abstract  A total of 121 bed sediment samples were collected from a 5.8-km stretch of Manoa Stream, Hawaii. Samples were physically partitioned into two grain-size fractions, 〈63 μm and 63–125 μm, acid digested and analyzed by ICP-AES and FAAS. Non-parametric matched-pair statistical testing and correlation analysis were used to assess differences and strengths of association between the two fractions for Al, Ba, Cu, Fe, Mn, Ni, Pb, Ti and Zn. Results indicated statistically significant differences between fractions for all elements except Mn. Concentrations were significantly greater in the 〈63 μm fraction for Al, Cu, Pb, Ti and Zn, while Ba, Fe and Ni were higher in the 63–125 μm fraction. Though some elements had statistically significant differences between fractions (Al, Ba, Fe and Zn) percentage differences were in the range of analytical precision of the instrument and thus differences were not practically significant. Correlation analysis indicated strong positive associations for all elements between the two fractions (p〈0.0001). Three contamination indices indicated similar degrees of pollution for each size fraction for four elements having an anthropogenic signal (Ba, Cu, Pb and Zn). The environmental information obtained from the 63–125 μm fraction was essentially equivalent to that from the 〈63 μm fraction. In this system it is clear that both bed sediment fractions indicate anthropogenic enrichment of trace metals, especially Pb, and further supports previous research that has found that aquatic sediments are critical median for tracing sources of pollution.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1007/s002540050012
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  • 2
    Electronic Resource
    Electronic Resource
    On the X 1∑+ state of KLi (2001)
    College Park, Md. : American Institute of Physics (AIP)
    The Journal of Chemical Physics 115 (2001), S. 4118-4124 
    Details
    ISSN: 1089-7690
    Source: AIP Digital Archive
    Topics: Physics , Chemistry and Pharmacology
    Notes: Laser-induced fluorescence spectra of the B–X system of 39K7Li, recorded on a Fourier transform interferometer, have allowed 47 vibrational levels of the electronic ground state to be observed. The ground state energies have been fitted to a Dunham polynomial expansion, and also directly to a numerical potential curve. Both fits reproduce the data to within the experimental accuracy of measurement (0.005 cm−1). © 2001 American Institute of Physics.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1063/1.1388555
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  • 3
    Electronic Resource
    Electronic Resource
    Structures and comparison of the Y98H (2.0 Å) and Y98W (1.5 Å) mutants of flavodoxin (Desulfovibrio vulgaris) (2001)
    Copenhagen : International Union of Crystallography (IUCr)
    Acta crystallographica 57 (2001), S. 527-535 
    Details
    ISSN: 1399-0047
    Source: Crystallography Journals Online : IUCR Backfile Archive 1948-2001
    Topics: Chemistry and Pharmacology , Geosciences , Physics
    Notes: The structures for two mutants at the Tyr98 site of Desulfovibrio vulgaris flavodoxin have been determined. The first, a tyrosine-to-histidine (Y98H) variant, was determined at the moderately high resolution of 2.0 Å, while the tyrosine-to-tryptophan variant (Y98W) yielded very high resolution data (beyond 1.5 Å) allowing a detailed look at the water structure, alternate side-chain conformations and the planarity of the FMN. Both structures were solved by molecular replacement beginning with the native (P2A) coordinates as a starting point. The Y98H variant of D. vulgaris flavodoxin crystallizes in space group P212121, with unit-cell parameters a = 41.96, b = 61.45, c = 57.04 Å, while the Y98W mutant adopts space group P21, with a = 41.29, b = 55.82, c = 32.52 Å, β = 100.68°. Refinement for both mutants utilized PROLSQ followed by, for the high-resolution Y98W structure, anisotropic refinement as implemented in SHELXL. Final R factors of 17% for the Y98H mutant and 9.8% for the Y98W mutant were obtained. For the high-resolution (1.5 Å) Y98W mutant, 31 010 unique reflections were collected from a single crystal. The final model includes 273 solvent molecules, with eight side chains assuming multiple conformations. At this resolution, the detailed conformation of the FMN can be observed, with both a bow and twist being noted. A comparison is made between the two mutants and the different oxidation states of the native flavodoxin. Although both mutants show similar E2 (oxidized/semiquinone) one-electron redox potentials to the native, the E1 (semiquinone/hydroquinone) redox potential for the Y98H mutant is significantly different from that of the Y98W variant and the native protein. The surprising similarity in the folding of the polypeptide chain 60–64 between the two mutants and the reduced states of the native is discussed. The interaction between O61 and N5 in the flavin is discussed because of the new conformation of this loop.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1107/S0907444901002554
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  • 4
    Electronic Resource
    Electronic Resource
    Woodrow Wilson, World War I, and American National Security (2001)
    Boston, USA and Oxford, UK : Blackwell Publishers Inc.
    Diplomatic history 25 (2001), S. 0 
    Details
    ISSN: 1467-7709
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: History , Political Science
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/0145-2096.00247
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  • 5
    Electronic Resource
    Electronic Resource
    PREDICTING HUMAN DRUG GLUCURONIDATION PARAMETERS: Application of In Vitro and In Silico Modeling Approaches (2004)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Pharmacology 44 (2004), S. 1-25 
    Details
    ISSN: 0362-1642
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Medicine , Chemistry and Pharmacology
    Notes: Cytochrome P450 (CYP) and UDP-glucuronosyltransferase (UGT), which both exist as enzyme "superfamilies," are together responsible for the metabolism of most hepatically cleared drugs. There is currently intense interest in the development of techniques that permit identification of the CYP and UGT isoform(s) involved in the metabolism of a newly discovered drug, and hence prediction of factors likely to alter elimination in vivo. In addition, the quantitative scaling of kinetic parameters for a metabolic pathway assumes importance for identifying newly discovered drugs with undesirable in vivo pharmacokinetic properties. Although qualitative and quantitative in vitro-in vivo correlation based on data generated using human liver tissue or recombinant enzymes have been applied successfully to many drugs eliminated by CYP, these strategies have proved less definitive for glucuronidated compounds. Computational (in silico) modeling techniques that potentially provide a facile and economic alternative to the in vitro methods are now emerging. This review assesses the utility of in vitro and in silico approaches for the qualitative and quantitative prediction of drug glucuronidation parameters and the challenges facing the development of generalizable models.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.pharmtox.44.101802.121546
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  • 6
    Electronic Resource
    Electronic Resource
    Ecology Global amphibian population declines (2001)
    [s.l.] : Nature Publishing Group
    Nature 412 (2001), S. 499-500 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The decline and disappearance of relatively undisturbed populations of amphibians in several high-altitude regions since the 1970s suggests that they may have suffered a global decline, perhaps with a common cause or causes. Houlahan et al. examined means of trends for 936 amphibian populations ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/35087658
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  • 7
    Electronic Resource
    Electronic Resource
    Antarctic climate cooling and terrestrial ecosystem response (2002)
    [s.l.] : Nature Publishing Group
    Nature 415 (2002), S. 517-520 
    Details
    ISSN: 1476-4687
    Source: Nature Archives 1869 - 2009
    Topics: Biology , Chemistry and Pharmacology , Medicine , Natural Sciences in General , Physics
    Notes: [Auszug] The average air temperature at the Earth's surface has increased by 0.06 °C per decade during the 20th century, and by 0.19 °C per decade from 1979 to 1998. Climate models generally predict amplified warming in polar regions, as observed in Antarctica's peninsula ...
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1038/nature710
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  • 8
    Electronic Resource
    Electronic Resource
    Restricted, but abundant, expression of the novel rat gene-3 (R3) relaxin in the dorsal tegmental region of brain (2002)
    Oxford, UK : Blackwell Science Ltd
    Journal of neurochemistry 82 (2002), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Relaxin is a peptide hormone with known actions associated with female reproductive physiology, but it has also been identified in the brain. Only one relaxin gene had been characterized in rodents until recently when a novel human relaxin gene, human gene-3 (H3) and its mouse equivalent (M3) were identified. The current study reports the identification of a rat homologue, rat gene-3 (R3) relaxin that is highly expressed in a discrete region of the adult brain. The full R3 relaxin cDNA was generated using RT-PCR and 3′ and 5′ RACE protocols. The derived amino acid sequence of R3 relaxin retains all the characteristic features of a relaxin peptide and has a high degree of homology with H3 and M3 relaxin. The distribution of R3 relaxin mRNA in adult rat brain was determined and highly abundant expression was only detected in neurons of the ventromedial dorsal tegmental nucleus (vmDTg) in the pons, whereas all other brain areas were unlabelled or contained much lower mRNA levels. Relaxin binding sites and relaxin immunoreactivity were also detected in the vmDTg. These together with earlier findings provide strong evidence for a role(s) for multiple relaxin peptides as neurotransmitters and/or modulators in the rat CNS.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1471-4159.2002.01114.x
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  • 9
    Electronic Resource
    Electronic Resource
    Organic carbon cycling in Taylor Valley, Antarctica: quantifying soil reservoirs and soil respiration (2001)
    Oxford, UK : Blackwell Science Ltd
    Global change biology 7 (2001), S. 0 
    Details
    ISSN: 1365-2486
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology , Energy, Environment Protection, Nuclear Power Engineering , Geography
    Notes: Organic carbon reservoirs and respiration rates in soils have been calculated for most major biomes on Earth revealing patterns related to temperature, precipitation, and location. Yet data from one of the Earth's coldest, driest, and most southerly soil ecosystems, that of the McMurdo Dry Valleys of Antarctica, are currently not a part of this global database. In this paper, we present the first regional calculations of the soil organic carbon reservoirs in a dry valley ecosystem (Taylor Valley) and report measurements of CO2 efflux from Antarctic soils. Our analyses indicate that, despite the absence of visible accumulations of organic matter in most of Taylor Valley's arid soils, this soil environment contained a significant percentage (up to 72%) of the seasonally unfrozen organic carbon reservoir in the terrestrial ecosystem. Field measurements of soil CO2-efflux in Taylor Valley soils were used to evaluate biotic respiration and averaged 0.10 ± 0.08 μmol CO2 m−2 s−1. Laboratory soil microcosms suggested that this respiration rate was sensitive to increases in temperature, moisture, and carbon addition. Finally, a steady-state calculation of the mean residence time for organic carbon in Taylor Valley soils was 23 years. Because this value contradicts all that is currently known about carbon cycling rates in the dry valleys, we suggest that the dry valley soil carbon dynamics is not steady state. Instead, we suggest that the dynamic is complex, with at least two (short- and long-term) organic carbon reservoirs. We also suggest that organic carbon in the dry valley soil environment may be more important, and play a more active role in long-term ecosystem processes, than previously believed.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1365-2486.2001.00393.x
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  • 10
    Electronic Resource
    Electronic Resource
    Demographic Analysis of a Disjunct Population of Froelichia floridana in the mid-Ohio River Valley (2002)
    Boston, MA, USA : Blackwell Science Inc
    Restoration ecology 10 (2002), S. 0 
    Details
    ISSN: 1526-100X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Biology
    Notes: Froelichia floridana (cottonweed) occurs as a disjunct population along the Ohio River in southeastern Ohio. The anomalous occurrence of F. floridana in this area has led to its designation as a state endangered species and a management regime to maintain the habitat conditions in which it occurs. As part of this effort, a restoration site was established on public lands in 1984 from seed collected in areas threatened by development. This study seeks to determine the demographic characteristics of this species in the restored and non-restored managed sites to provide basic ecological information regarding life history parameters and to judge the effectiveness of the restoration. For two years (1997–1998) we collected information on seed bank abundance, field seed germination, plant survivorship, and seed production to create a stage-based transition matrix model. The model suggests that population growth and abundance as assayed by λ (rate of increase) are stable to declining and are similar between the restoration and natural sites. A reduction in competition had a positive effect on population growth. Elasticity analysis showed that plants germinating earlier in the spring and becoming established as an early cohort contributed a greater level of reproductive output than plants germinating in late spring. Lowered population growth for 1997 is attributed to a cooler and dryer than average early spring that delayed germination and subsequent seed production. Elasticity analysis also suggested that the presence of a persistent seed bank was crucial for long-term population maintenance and may allow for recovery in areas of low aboveground abundance through soil manipulation.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1046/j.1526-100X.2002.02021.x
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