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  • 1
    Electronic Resource
    Electronic Resource
    Fused quartz couplings for capillary columns and restrictors in SFC (1992)
    Weinheim : Wiley-Blackwell
    Journal of High Resolution Chromatography 15 (1992), S. 341-343 
    Details
    ISSN: 0935-6304
    Keywords: Capillary SFC ; Column coupling ; Restrictor ; Dead volume ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/jhrc.1240150514
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    Paper (German National Licenses)
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  • 2
    Electronic Resource
    Electronic Resource
    The effect of temperature on selectivity in capillary SFC (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 4 (1992), S. 215-220 
    Details
    ISSN: 1040-7685
    Keywords: retention index ; supercritical fluid chromatography ; selectivity ; temperature ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: Retention indices (RI) for a variety of probe compounds were determined on 50-μm i. d. columns coated with eight different stationary phases under density programmed SFC conditions at isothermal temperatures of 80 and 150°C. RI values were strongly dependent on temperature for polar probes on the polar phases containing high levels of cyanopropyl or polyethylene glycol (PEG) functionality. A lower apparent polarity was observed for polar columns at higher temperatures. Moderate RI differences were apparent with the same probes on columns with polarizable stationary phases of high phenyl or biphenyl content. Nonpolar alkyl substituted stationary phases showed only a slight temperature dependence on RI for all test compounds. Alkanes of lower molecular weight eluted at lower densities on all columns when the temperature was raised because of the contribution of volatility to elution in SFC. This same effect was observed for the higher alkanes on both nonpolar and PEG columns, but they eluted at similar densities on cyanopropyl columns and at higher densities on columns with polarizable phases when the temperature was raised. Temperature controlled selectivity tuning is a useful tool in optimizing separations in SFC.
    Additional Material: 4 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mcs.1220040306
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    Paper (German National Licenses)
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  • 3
    Electronic Resource
    Electronic Resource
    Degradation and regeneration of the cross-linking agent azo-t-butane (1992)
    New York, NY [u.a.] : Wiley-Blackwell
    Journal of Microcolumn Separations 4 (1992), S. 221-225 
    Details
    ISSN: 1040-7685
    Keywords: Azo-t-butane ; cross-linking ; immobilization ; capillary columns ; Chemistry ; Analytical Chemistry and Spectroscopy
    Source: Wiley InterScience Backfile Collection 1832-2000
    Topics: Chemistry and Pharmacology
    Notes: The ability of commercially available azo-t-butun (ATB) to facilitate immobilization of polysiloxane stationary phases in capillary columns deteriorates upon storage. Aged ATB produces columns with high bleed, solute retention shifts, erratic immobilization efficiency, and high activity. This deterioration is accelerated in the presence of light, suggesting free radical processes are involved. The loss of certain lowlevel impurities, which act as free radical transfer agents or radical sinks, may be responsible for the performance change. Regeneration can often temporarily be accomplished using platinum catalyzed reduction with trichlorosilane. The addition of small amounts of toluene or other radical transfer agents to aged ATB moderates the cross-linking process, allowing the reproducible production of columns with good immobilization efficiency, excellent intertness, low thermal bleed, and proper polarity.
    Additional Material: 3 Ill.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1002/mcs.1220040307
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    Paper (German National Licenses)
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  • 4
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    Habitat, not resource availability, limits consumer production in lake ecosystems (2015)
    Wiley-Blackwell
    Details
    Publication Date: 2015-09-04
    Description: Food web productivity in lakes can be limited by dissolved organic carbon (DOC), which reduces fish production by limiting the abundance of their zoobenthic prey. We demonstrate that in a set of 10 small, north temperate lakes spanning a wide DOC gradient, these negative effects of high DOC concentrations on zoobenthos production are driven primarily by availability of warm, well-oxygenated habitat, rather than by light limitation of benthic primary production as previously proposed. There was no significant effect of benthic primary production on zoobenthos production after controlling for oxygen, even though stable isotope analysis indicated that zoobenthos do use this resource. Mean whole-lake zoobenthos production was lower in high-DOC lakes with reduced availability of oxygenated habitat, as was fish biomass. These insights improve understanding of lake food webs and inform management in the face of spatial variability and ongoing temporal change in lake DOC concentrations.
    Print ISSN: 0024-3590
    Electronic ISSN: 1939-5590
    Topics: Biology , Geosciences , Physics
    Published by Wiley-Blackwell on behalf of The Association for the Sciences of Limnology and Oceanography (ASLO).
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  • 5
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    Life history constraints explain negative relationship between fish productivity and dissolved organic carbon in lakes (2017)
    Wiley-Blackwell
    Details
    Publication Date: 2017-07-04
    Description: Resource availability constrains the life history strategies available to organisms and may thereby limit population growth rates and productivity. We used this conceptual framework to explore the mechanisms driving recently reported negative relationships between fish productivity and dissolved organic carbon (DOC) concentrations in lakes. We studied populations of bluegill ( Lepomis macrochirus ) in a set of lakes with DOC concentrations ranging from 3 to 24 mg/L; previous work has demonstrated that primary and secondary productivity of food webs is negatively related to DOC concentration across this gradient. For each population, we quantified individual growth rate, age at maturity, age-specific fecundity, maximum age, length-weight and length-egg size relationships, and other life history characteristics. We observed a strong negative relationship between maximum size and DOC concentration; for instance, fish reached masses of 150 to 260 g in low-DOC lakes but 〈120 g in high-DOC lakes. Relationships between fecundity and length, and between egg size and length, were constant across the DOC gradient. Because fish in high-DOC lakes reached smaller sizes but had similar fecundity and egg size at a given size, their total lifetime fecundity was as much as two orders of magnitude lower than fish in low-DOC lakes. High DOC concentrations appeared to constrain the range of bluegill life history strategies available; populations in high-DOC lakes always had low initial growth rates and high ages at maturity, whereas populations in low-DOC showed higher variability in these traits. This was also the case for the intrinsic rates of natural increase of these populations, which were always low at the high end of the DOC gradient. The potentially lower capacity for fish populations in high-DOC lakes to recover from exploitation has clear implications for the sustainable management of recreational fisheries in the face of considerable spatial heterogeneity and ongoing temporal change in lake DOC concentrations. We explored the mechanisms driving recently reported negative relationships between fish productivity and dissolved organic carbon (DOC) concentrations in lakes using a multi-lake study. We observed a strong negative relationship between maximum size and DOC concentration; because fish in high-DOC lakes were smaller but had similar fecundity and egg size at a given size, their total lifetime fecundity was as much as two orders of magnitude lower than fish in low-DOC lakes. High DOC concentrations appeared to constrain the range of bluegill life history strategies available.
    Electronic ISSN: 2045-7758
    Topics: Biology
    Published by Wiley-Blackwell
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  • 6
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    Dissolved organic carbon concentration controls benthic primary production: Results from in situ chambers in north-temperate lakes (2015)
    Wiley-Blackwell
    Details
    Publication Date: 2015-01-06
    Description: We evaluated several potential drivers of primary production by benthic algae (periphyton) in north-temperate lakes. We used continuous dissolved oxygen measurements from in situ benthic chambers to quantify primary production by periphyton at multiple depths across 11 lakes encompassing a broad range of dissolved organic carbon (DOC) and total phosphorous (TP) concentrations. Light-use efficiency (primary production per unit incident light) was inversely related to average light availability (% of surface light) in 7 of the 11 study lakes, indicating that benthic algal assemblages exhibit photoadaptation, likely through physiological or compositional changes. DOC alone explained 86% of the variability in log-transformed whole-lake benthic production rates. TP was not an important driver of benthic production via its effects on nutrient and light availability. This result is contrary to studies in other systems, but may be common in relatively pristine north-temperate lakes. Our simple empirical model may allow for the prediction of whole-lake benthic primary production from easily obtained measurements of DOC concentration.
    Print ISSN: 0024-3590
    Electronic ISSN: 1939-5590
    Topics: Biology , Geosciences , Physics
    Published by Wiley-Blackwell on behalf of The Association for the Sciences of Limnology and Oceanography (ASLO).
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  • 7
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    Erratum Dissolved organic carbon concentration controls benthic primary production: Results from in situ chambers in north-temperate lakes (2015)
    Wiley-Blackwell
    Details
    Publication Date: 2015-11-29
    Print ISSN: 0024-3590
    Electronic ISSN: 1939-5590
    Topics: Biology , Geosciences , Physics
    Published by Wiley-Blackwell on behalf of The Association for the Sciences of Limnology and Oceanography (ASLO).
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  • 8
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    A phase I dose-ranging study of bendamustine and rituximab in chronic lymphocytic leukemia patients with comorbidities (2016)
    Wiley-Blackwell
    Details
    Publication Date: 2016-07-06
    Print ISSN: 0007-1048
    Electronic ISSN: 1365-2141
    Topics: Medicine
    Published by Wiley-Blackwell
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