43 research outputs found

    Solvent-dependent photo-induced dynamics in a non-rigidly linked zinc phthalocyanine-perylenediimide dyad probed using ultrafast spectroscopy

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    In this work, we characterize the energy and electron transfer kinetics of a zinc phthalocyanine-perylenediimide dyad (ZnPc-PDI) in various solvents using steady-state and tunable narrowband pump-probe spectroscopy. We fit the ultrafast data with global analysis techniques and find that upon excitation of the PDI moiety (pump pulse at 540 nm), the excitation energy transfer (EET) rate to the ZnPc moiety displays a solvent sensitivity that we attribute to changes in the relative equilibrium moiety orientation. We rationalize these observations by considering the nature of the non-rigid bridge used to link the two moieties as well as the degenerate nature of the Q band transitions in the ZnPc species. By tuning the pulse into resonance with the ZnPc Q band (685 nm) we can directly photo-induce an electron transfer (ET) process back to the PDI moiety. Employing the same global analysis, we find that the dynamics of the ultrafast electron transfer are completely kinetically controlled according to the Bixon-Jortner model of barrierless solvent-controlled curve crossing, while the recombination to reform the ground state is well-described using the static energetic picture according to Marcus theory

    Examining the Incremental Validity and Adverse Impact of Cognitive Ability and Conscientiousness On Job Performance

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    Using archival data from a large home improvement organization, the current study examined the incremental validity of conscientiousness over cognitive ability in predicting different performance criteria. Also, the study examined the effects of conscientiousness and cognitive ability on adverse impact. Results indicated that conscientiousness provided incremental validity over cognitive ability in the prediction of several performance criteria. Specifically, conscientiousness had the highest increases in validity over cognitive ability in the prediction of contextual performance factors (e.g., contextual performance, customer service orientation, dealing with others). However, the addition of conscientiousness failed to ameliorate the adverse impact associated with cognitive ability. In addition, limitations of the study and future directions of research are addressed

    Conscientiousness as a Predictor of Productive and Counterproductive Behaviors

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    This article extends the integrity testing literature by examining relationships between conscientiousness subscales and productive and counterproductive workplace behaviors. Correlational analyses (n = 359 employees) indicated conscientiousness predicted overall performance, supervisors\u27 willingness to rehire and employee attendance, but not integrity/safety ratings. Conscientiousness subscales differentially predicted criteria and were more parsimonious

    Advanced Glycation End-Product Accumulation Reduces Vitreous Permeability

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    PurposeTo evaluate the effect of nonenzymatic cross-linking (glycation) upon the permeability of the vitreous to small- and large-solute diffusion.MethodsVitreous from freshly excised porcine eyes was treated for 30 minutes with control or 0.01%, 0.1%, or 1% methylglyoxal (MG) solution. The efficacy of the glycation regimen was verified by measuring nonenzymatic cross-link density by fluorescence in the vitreous samples. Resistance to collagenase digestion as well as N(ε)-(carboxyethyl) lysine (CEL) content were also measured. The permeability coefficient for fluorescein and fluorescein isothiocyanate (FITC)-IgG diffusion through 3 mL of the vitreous samples was determined by using a custom permeability tester.ResultsVitreous cross-linking with MG treatment was confirmed by increased fluorescence, increased CEL concentration, and increased resistance to collagenase digestion. Vitreous glycation resulted in a statistically significant decrease in the permeability coefficient for fluorescein diffusion when either 0.1% or 1% MG solution was used (5.36 ± 5.24 × 10(-5) cm s(-1), P = 0.04; and 4.03 ± 2.1 × 10(-5) cm s(-1), P = 0.001; respectively, compared with control, 9.77 ± 5.45 × 10(-5) cm s(-1)). The permeability coefficient for diffusion of FITC-IgG between control (9.9 ± 6.37 × 10(-5) cm s(-1)) and treatment groups was statistically significant at all MG concentrations (0.01% MG: 3.95 ± 3.44 × 10(-5) cm s(-1), P = 0.003; 0.1% MG: 4.27 ± 1.32 × 10(-5) cm s(-1), P = 0.004; and 0.1% MG: 3.72 ± 2.49 × 10(-5) cm s(-1), P = 0.001).ConclusionsAdvanced glycation end-product (AGE) accumulation reduces vitreous permeability when glycation is performed in ex vivo porcine vitreous. The permeability change was more pronounced for the larger solute, suggesting a lower threshold for AGE-induced permeability changes to impact the movement of proteins through the vitreous when compared with smaller molecules

    Synthesis of hemoglobin F in adult simian erythroid progenitor-derived colonies.

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