119 research outputs found

    Analysis of unresolved complex mixtures of hydrocarbons extracted from Late Archean sediments by comprehensive two-dimensional gas chromatography (GC×GC)

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    Author Posting. © Elsevier B.V., 2008. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Organic Geochemistry 39 (2008): 846-867, doi:10.1016/j.orggeochem.2008.03.006.Hydrocarbon mixtures too complex to resolve by traditional capillary gas chromatrography display gas chromatograms with dramatically rising baselines or “humps” of coeluting compounds that are termed unresolved complex mixtures (UCMs). Because the constituents of UCMs are not ordinarily identified, a large amount of geochemical information is never explored. Gas chromatograms of saturated/unsaturated hydrocarbons extracted from Late Archean argillites and greywackes of the southern Abitibi Province of Ontario, Canada contain UCMs with different appearances or “topologies” relating to the intensity and retention time of the compounds comprising the UCMs. These topologies appear to have some level of stratigraphic organization, such that samples collected at any stratigraphic formation collectively are dominated by UCMs that either elute early- (within a window of C15-C20 of n-alkanes), early- to mid- (C15-C30 of n-alkanes), or have a broad UCM that extends through the entire retention time of the sample (from C15-C42 of n-alkanes). Comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC×GC-MS) was used to resolve the constituents forming these various UCMs. Early- to mid- eluting UCMs are dominated by configurational isomers of alkyl-substituted and non substituted polycyclic compounds that contain up to six rings. Late eluting UCMs are composed of C36-C40 mono-, bi-, and tricyclic archaeal isoprenoid diastereomers. Broad UCMs spanning the retention time of compound elution contain nearly the same compounds observed in the early-, mid-, and late retention time UCMs. Although the origin of the polycyclic compounds is unclear, the variations in the UCM topology appear to depend on the concentration of initial compound classes that have the potential to become isomerized. Isomerization of these constituents may have resulted from hydrothermal alteration of organic matter.This project was supported by NASA Exobiology grant #NAG5-13446 to Fabien Kenig. GC×GC analysis was supported by NSF grant IIS-0430835 and the Seaver Foundation to Christopher M. Reddy. Preparation of the archaeal biphytane standard was supported by NSF grant ARC-0520226 to Benjamin Van Mooy

    Protein-retention expansion microscopy of cells and tissues labeled using standard fluorescent proteins and antibodies

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    Expansion microscopy (ExM) enables imaging of preserved specimens with nanoscale precision on diffraction-limited instead of specialized super-resolution microscopes. ExM works by physically separating fluorescent probes after anchoring them to a swellable gel. The first ExM method did not result in the retention of native proteins in the gel and relied on custom-made reagents that are not widely available. Here we describe protein retention ExM (proExM), a variant of ExM in which proteins are anchored to the swellable gel, allowing the use of conventional fluorescently labeled antibodies and streptavidin, and fluorescent proteins. We validated and demonstrated the utility of proExM for multicolor super-resolution (~70 nm) imaging of cells and mammalian tissues on conventional microscopes.United States. National Institutes of Health (1R01GM104948)United States. National Institutes of Health (1DP1NS087724)United States. National Institutes of Health ( NIH 1R01EY023173)United States. National Institutes of Health (1U01MH106011

    Using Parahydrogen Induced Polarization to Study Steps in the Hydroformylation Reaction.

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    A range of iridium complexes, Ir(η3-C3H5)(CO)(PR2R’)2 (1a-1e) [where 1a, PR2R’ = PPh3, 1b P(p-tol)3, 1c PMePh2, 1d PMe2Ph and 1e PMe3] were synthesized and their reactivity as stoichiometric hydroformylation precursors studied. Para-hydrogen assisted NMR spectroscopy detected the following intermediates: Ir(H)2(η3-C3H5)(CO)(PR2R’) (2a-e), Ir(H)2(η1-C3H5)(CO)(PR2R’)2 (4d-e), Ir(H)2(η1-C3H5)(CO)2(PR2R’) (10a-e), Ir(H)2(CO-C3H5)(CO)2(PR2R’) (11a-c), Ir(H)2(CO-C3H7)(CO)2(PR2R’) (12a-c) and Ir(H)2(CO-C3H5)(CO)(PR2R’)2 (13d-e). Some of these species exist as two geometric isomers according to their multinuclear NMR characteristics. The NMR studies suggest a role for the following 16 electron species in these reactions: Ir(η3-C3H5)(CO)(PR2R’), Ir(η1-C3H5)(CO)(PR2R’)2, Ir(η1-C3H5)(CO)2(PR2R’), Ir(CO-C3H5)(CO)2(PR2R’), Ir(CO-C3H7)(CO)2(PR2R’) and Ir(CO-C3H5)(CO)(PR2R’)2. Their role is linked to several 18 electron species in order to confirm the route by which hydroformylation and hydrogenation proceeds

    Competition and Combative Advertising: An Historical Analysis

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    Fred K. Beard (PhD, University of Oklahoma) is a professor of advertising in the Gaylord College of Journalism and Mass Communication, University of Oklahoma. His research interests include comparative advertising, advertising humor, and advertising history. His work has appeared in the Journal of Advertising, the Journal of Advertising Research, the Journal of Business Ethics, the Journal of Business Research, Journalism History, the Journal of Historical Research in Marketing, the Journal of Macromarketing, and the Journal of Marketing Communications, among others.Yeshttps://us.sagepub.com/en-us/nam/manuscript-submission-guideline

    Outcome measures for the evaluation of treatment response in hidradenitis suppurativa for clinical practice

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    Importance Although several clinician- and patient-reported outcome measures have been developed for trials in hidradenitis suppurativa (HS), there is currently no consensus on which measures are best suited for use in clinical practice. Identifying validated and feasible measures applicable to the practice setting has the potential to optimize treatment strategies and generate generalizable evidence that may inform treatment guidelines. Objective To establish consensus on a core set of clinician- and patient-reported outcome measures recommended for use in clinical practice and to establish the appropriate interval within which these measures should be applied. Evidence Review Clinician- and patient-reported HS measures and studies describing their psychometric properties were identified through literature reviews. Identified measures comprised an item reduction survey and subsequent electronic Delphi (e-Delphi) consensus rounds. In each consensus round, a summary of outcome measure components and scoring methods was provided to participants. Experts were provided with feasibility characteristics of clinician measures to aid selection. Consensus was achieved if at least 67% of respondents agreed with use of a measure in clinical practice. Findings Among HS experts, response rates for item reduction, e-Delphi round 1, and e-Delphi round 2 surveys were 76.4% (42 of 55), 90.5% (38 of 42), and 92.9% (39 of 42), respectively; among patient research partners (PRPs), response rates were 70.8% (17 of 24), 100% (17 of 17), and 82.4% (14 of 17), respectively. The majority of experts across rounds were practicing dermatologists with 18 to 19 years of clinical experience. In the final e-Delphi round, most PRPs were female (12 [85.7%] vs 2 males [11.8%]) and aged 30 to 49 years. In the final e-Delphi round, HS experts and PRPs agreed with the use of the HS Investigator Global Assessment (28 [71.8%]) and HS Quality of Life score (13 [92.9%]), respectively. The most expert-preferred assessment interval in which to apply these measures was 3 months (27 [69.2%]). Conclusions and Relevance An international group of HS experts and PRPs achieved consensus on a core set of HS measures suitable for use in clinical practice. Consistent use of these measures may lead to more accurate assessments of HS disease activity and life outcomes, facilitating shared treatment decision-making in the practice setting

    Cross-cultural variations in climate for autonomy, stress and organizational productivity relationships:A comparison of Chinese and UK manufacturing organizations

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    Cross-cultural researchers have questioned the extent to which European– American management practices can be transported to major markets in Asia, such as the People’s Republic of China. Applying employee involvement theory, we examined the relationships between climate for autonomy, work demands climate, employee stress and organizational productivity in a crossnational study of 51 UK and 104 Chinese manufacturing organizations. We predicted and found that climate for autonomy was positively and negatively related to stress in the Chinese and UK contexts, respectively. The interaction of climate for autonomy and work demands climate was significant: climate for autonomy was positively related to organizational productivity only when work demands climate was low
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