Synthesis of new fluorene-based copolymers containing an anthracene derivative and their applications in polymeric light-emitting diodes

We report the synthesis of copolymers containing fluorene and highly soluble anthracene derivatives, of general formula, poly{9,9'-bis-(4-octoloxy-phenyl)-fluorene-2,7-diyl-co-9,10-bis-(decy-1-ynyl)-anthracene-2,6-diyl}s (PFAnts). The PFAnts were synthesized via Suzuki coupling and the feed ratios of the anthracene derivative (Ant) were 1, 5, 10, 30, and 50 mol % of the total amount of monomer. PFAnts showed well-defined high molecular weights and were more soluble in conventional organic solvents. The photoluminescence spectra of PFAnts shifted to longer wavelengths with increases in Ant proportion and the PFAnts emitted various colors varying from greenish-blue to orange. The highest occupied molecular orbital and lowest unoccupied molecular orbital energy levels trended toward enhanced hole and electron recombination balance as the Ant proportion increased, due to the better electron-accepting ability of the anthracene moiety compared to the fluorene moiety. Polymeric light-emitting diodes with the configurations ITO/PEDOT:PSS(40 nm)/polymer(60 nm)/Ca(10 nm)/Al(100 nm) (Device A) and ITO/PEDOT:PSS(40 nm)/polymer(60 nm)/Balq(40 nm)/LiF(1 nm)/Al(100 nm) (Device B) were fabricated using the polymers as emissive layers. Especially, Device B with PFAnt01 exhibited the highest measured maximum brightness of 1760 cd/m2 at 14 V, a maximum current efficiency of 1.66 cd/A, and a maximum external quantum efficiency of 0.70%.     

Can expensive research equipment boost research and development performances?

Scientometrics - Research equipment is as essential for researchers as modes of transportation are for travelers. Thus, to ascertain the extent to which research equipment affects research...     

AP Collagen Peptides Prevent Cortisol-Induced Decrease of Collagen Type I in Human Dermal Fibroblasts

Cortisol is an endogenous glucocorticoid (GC) and primary stress hormone that regulates a wide range of stress responses in humans. The adverse effects of cortisol on the skin have been extensively documented but the underlying mechanism of cortisol-induced signaling is still unclear. In the present study, we investigate the effect of cortisol on collagen type I expression and the effect of AP collagen peptides, collagen tripeptide-rich hydrolysates containing 3% glycine-proline- hydroxyproline (Gly-Pro-Hyp, GPH) from the fish skin, on the cortisol-mediated inhibition of collagen type I and the cortisol-induced signaling that regulates collagen type I production in human dermal fibroblasts (HDFs). We determine that cortisol downregulates the expression of collagen type I. AP collagen peptides or GC receptor (GR) inhibitors recover the cortisol-mediated inhibition of collagen type I and GR activation. AP collagen peptides or GR inhibitors also prevent the cortisol-dependent inhibition of transforming growth factor (TGF)-β signaling. AP collagen peptides or GR inhibitors are effective in the prevention of collagen type I inhibition mediated by cortisol in senescent HDFs and reconstituted human skin models. Taken together, GR signaling might be responsible for the cortisol-mediated inhibition of TGF-β. AP collagen peptides act as GR-mediated signaling blockers, preventing the cortisol-dependent inhibition of collagen type I. Therefore, AP collagen peptides have the potential to improve skin health.     

Effects of high pressure processing on fatty acid composition and volatile compounds in Korean native black goat meat

This study investigated the effects of high pressure processing (HPP) on fatty acid composition and volatile compounds in Korean native black goat (KNBG) meat. Fatty acid content in KNBG meat was not significantly (p > 0.05) different among the control goats and those subjected HPP. The 9,12-octadecadienoic acid and octadecanoic acid, well-known causes of off-flavors, were detected from meat of some KNBG. A difference between the control and HPP treatment was observed in the discriminated function analysis using an electronic nose. The results suggest that the volatile compounds in KNBG meat were affected by HPP.     

Brain Atrophy and White Matter Damage Linked to Peripheral Bioenergetic Deficits in the Neurodegenerative Disease FXTAS

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder affecting subjects (premutation carriers) with a 55-200 CGG-trinucleotide expansion in the 5′UTR of the fragile X mental retardation 1 gene (FMR1) typically after age 50. As both the presence of white matter hyperintensities (WMHs) and atrophied gray matter on magnetic resonance imaging (MRI) are linked to age-dependent decline in cognition, here we tested whether MRI outcomes (WMH volume (WMHV) and brain volume) were correlated with mitochondrial bioenergetics from peripheral blood monocytic cells in 87 carriers with and without FXTAS. As a parameter assessing cumulative damage, WMHV was correlated to both FXTAS stages and age, and brain volume discriminated between carriers and non-carriers. Similarly, mitochondrial mass and ATP production showed an age-dependent decline across all participants, but in contrast to WMHV, only FADH₂-linked ATP production was significantly reduced in carriers vs. non-carriers. In carriers, WMHV negatively correlated with ATP production sustained by glucose-glutamine and FADH₂-linked substrates, whereas brain volume was positively associated with the latter and mitochondrial mass. The observed correlations between peripheral mitochondrial bioenergetics and MRI findings—and the lack of correlations with FXTAS diagnosis/stages—may stem from early brain bioenergetic deficits even before overt FXTAS symptoms and/or imaging findings.     

Lay theory of race affects and moderates Asian Americans' responses toward American culture.

People may hold different understandings of race that might affect how they respond to the culture of groups deemed to be racially distinct. The present research tests how this process is moderated by the minority individual's lay theory of race. An essentialist lay theory of race (i.e., that race reflects deep-seated, inalterable essence and is indicative of traits and ability) would orient racial minorities to rigidly adhere to their ethnic culture, whereas a social constructionist lay theory of race (i.e., that race is socially constructed, malleable, and arbitrary) would orient racial minorities to identify and cognitively assimilate toward the majority culture. To test these predictions, the authors conducted 4 studies with Asian American participants. The first 2 studies examine the effect of one's lay theory of race on perceived racial differences and identification with American culture. The last 2 studies tested the moderating effect of lay theory of race on identification and assimilation toward the majority American culture after this culture had been primed. The results generally supported the prediction that the social constructionist theory was associated with more perceived similarity between Asians and Americans and more consistent identification and assimilation toward American culture, compared with the essentialist theory. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Stable anatase TiO₂ coating on quartz fibers by atomic layer deposition for photoactive light-scattering in dye-sensitized solar cells

Quartz fibers provide a unique high surface-area substrate suitable for conformal coating using atomic layer deposition (ALD), and are compatible with high temperature annealing. This paper shows that the quartz fiber composition stabilizes ALD TiO(2) in the anatase phase through TiO(2)-SiO(2) interface formation, even after annealing at 1050 °C. When integrated into a dye-sensitized solar cell, the TiO(2)-coated quartz fiber mat improves light scattering performance. Results also confirm that annealing at high temperature is necessary for better photoactivity of ALD TiO(2), which highlights the significance of quartz fibers as a substrate. The ALD TiO(2) coating on quartz fibers also boosts dye adsorption and photocurrent response, pushing the overall efficiency of the dye-cells from 6.5 to 7.4%. The mechanisms for improved cell performance are confirmed using wavelength-dependent incident photon to current efficiency and diffuse light scattering results. The combination of ALD and thermal processing on quartz fibers may enable other device structures for energy conversion and catalytic reaction applications.