Charge Generation and Recombination in Fullerene-Attached Poly(3-hexylthiophene)-Based Diblock Copolymer Films

The charge generation and recombination dynamics in fullerene-attached poly­(3-hexythiophene) (P3HT)-based diblock copolymer were studied in comparison with those in blend films of P3HT and a fullerene derivative (PCBM) in order to understand the potential advantage of diblock copolymer-based polymer solar cells. Upon photoexcitation, P3HT singlet excitons are promptly converted to P3HT polarons with a time constant of ∼30 ps in both P3HT-PCBM diblock copolymer and P3HT/PCBM blend films. This similar charge generation dynamics is indicative of analogous phase-separated morphology both in these films on a scale of nanometers. After the charge generation, a part of polarons in disorder phases geminately recombine to the ground state in diblock copolymer films, while no geminate recombination is observed in blend films. This geminate recombination loss is probably due to defects of phase-separated structures in diblock copolymer films. On the other hand, charge carrier lifetime is as long as 15 μs in diblock copolymer films. Such a long carrier lifetime may result in a relatively high fill factor in P3HT-PCBM copolymer films. Finally, we discuss the overall device performance in terms of phase-separated structures

Ectopic bone formation analyses.

<p>A: Bone formation capability of muscle-derived cells. Representative histological sections of a scaffold loaded with BMSCs or MuSCs cultured with both dexamethasone and BMP-2. Scale bar: 1 mm (left panels), 200 μm (middle panels) and 50 μm (right panels). Black arrows indicate new bone formation in the scaffold. Black arrow heads indicate osteocytes and green arrow heads indicate bone lining cells. B: Newly formed bone, T: β-TCP, P: Porous area. B: Recruitment of cells residing in muscle tissue to participate in BMP-2-induced ectopic bone formation. Cells labeled prior to local BMP-2 administration were detected in the newly formed woven bone area. Representative histological sections were stained with H&E and evaluated for i-QD fluorescence. The black arrows in the H&E image show the locations of fluorescently labeled cells indicated with white arrows in the fluorescent image. Scale bar: 200 μm. B: Newly formed bone, T: β-TCP, P: Porous area. C: Augmentation of ectopic bone formation by dexamethasone. C-1, 2: Representative histological sections of an excised scaffold that had been loaded with BMP-2 alone and a scaffold that had been loaded with dexamethasone and BMP-2. The sections were stained with H&E and immunostained for osteocalcin. Black arrows indicate new bone formation in the scaffold. Red arrows indicate osteocalcin positive staining area. Scale bar: 1 mm (top panels of C-1), 200 μm (bottom panels of C-1) and 50 μm (C-2). B: Newly formed bone, T: β-TCP, P: Porous area. C-3: Quantification of bone formation at 3 weeks after transplantation. The Y axis indicates the bone formation ratio calculated as total bone area/total scaffold area. Each bar represents the mean with the standard deviation (SD). *denotes <i>P</i> < 0.05.</p

Dexamethasone pretreatment and osteogenic induction with combined dexamethasone and BMP-2 treatment enhance the osteogenic differentiation of BMSCs and MuSCs.

<p>A: Schematic representation of the cell culture protocol. Gross images of ALP staining (ALP) and Von Kossa staining (VK) of BMSCs (B) and MuSCs (D). Quantitative analysis of the mRNA expression of ALP and osteocalcin in BMSCs (C) and MuSCs (E). The fold change in gene expression was normalized to that of BM-Dex-AG or Mu-Dex-AG. Bars show the mean and SEM. Statistical significance was confirmed between the BM and BM-Dex groups (ALP: p = 0.015, OCN: p = 0.023) and between the Mu and Mu-DEX groups (ALP: p = 0.019, OCN: p = 0.015). Effects of combinations of differentiation reagents were significant for ALP in BM-Dex (p = 0.032) and Mu-DEX (p = 0.019) and for OCN in Mu-DEX (p = 0.024).</p

Western blot analyses of the SMAD1/5/8 and phosphorylation of SMAD 1/5.

<p>Western blot analyses of P-SMAD 1/5, SMAD1/5/8 and α-tubulin expression in BMSCs (A) and MuSCs (B) under four different osteogenic induction conditions with or without dexamethasone.</p

Dexamethasone affects cell proliferation during osteogenic differentiation.

<p>The absorbance at 585 nm was measured for dye extracted from the wells, and ratios relative to the standard are presented in the graphs. A: BM, B: BM-Dex, C: Mu, and D: Mu-Dex</p

Colony formation assay of BMSCs and MuSCs.

<p>A: Schematic representation of the colony formation unit assay protocol. Cells seeded at P2 were allowed to form single-cell-derived colonies with or without 10^-7 M dexamethasone for 7 days before osteogenic induction. ND-ND indicates normal growth medium at P0, P1, and P2. ND-D indicates normal growth medium at P0 and P1 and dexamethasone-containing medium at P2. D-ND indicates dexamethasone-containing medium at P0 and P1 and normal growth medium at P2. D-D indicates dexamethasone-containing medium at P0, P1, and P2. Gross images of BMSCs (B) and MuSCs (D) in each dish stained by ALP and crystal violet. Quantification of the total colony number and fraction of ALP-positive colonies (%) among total colonies in BMSCs (C) and MuSCs (E). *** denotes P < 0.001 as determined by Student’s t-test.</p

RT-PCR primers used in this study.

<p>RT-PCR primers used in this study.</p

New Genetic Biomarkers Predicting Azathioprine Blood Concentrations in Combination Therapy with 5-Aminosalicylic Acid

<div><p>Background and Aims</p><p>Azathioprine (AZA) is widely used for the treatment of inflammatory bowel disease (IBD) patients. AZA is catabolized by thiopurine S-methyltransferase (TPMT), which exhibits genetic polymorphisms. It has also been reported that 5-aminosalicylic acid (5-ASA) inhibits TPMT activity, and that increased 6-thioguanine nucleotide (6-TGN, a metabolite of AZA) blood concentrations result in an increased number of ADRs. In this study, single nucleotide polymorphisms (SNPs) related to differential gene expression affecting AZA drug metabolism in combination therapy with 5-ASA were examined.</p><p>Methods</p><p>To identify genetic biomarkers for the prediction of 6-TGN blood concentration, ExpressGenotyping analysis was used. ExpressGenotyping analysis is able to detect critical pharmacogenetic SNPs by analyzing drug-induced expression allelic imbalance (EAI) of premature RNA in HapMap lymphocytes. We collected blood samples on 38 patients with inflammatory bowel disease treated with AZA and corroboration of the obtained SNPs was attempted in clinical samples.</p><p>Results</p><p>A large number of SNPs with AZA/5-ASA-induced EAI within the investigated HapMap lymphocytes was identified by ExpressGenotyping analysis. The respective SNPs were analyzed in IBD patients' blood samples. Among these SNPs, several that have not yet been described to be induced by AZA/5-ASA were found. SNPs within SLC38A9 showed a particular correlation with patients' 6-TGN blood concentrations.</p><p>Conclusions</p><p>Based on these results, ExpressGenotyping analysis and genotyping of patients appears to be a useful way to identify inter-individual differences in drug responses and ADRs to AZA/5-ASA. This study provides helpful information on genetic biomarkers for optimized AZA/5-ASA treatment of IBD patients.</p></div

Results of drug-induced EAI for SNP (rs6897117) of SLC38A9.

<p>The SNP of SLC38A9 shows a consistent relationship between 6-TGN risk ratios and drug-induced EAI.</p

Clinical information of drug administration for patients.

<p>Clinical information related to drug administration for patients.</p><p>Since the 5-ASA dose was less than 2000 mg/day in sample numbers 3, 8, 13, 28, 35, and 38, they were not used for data analysis in this study.</p