A Series of Pyrene‐Substituted Silicon Phthalocyanines as Near‐IR Sensitizers in Organic Ternary Solar Cells

An attractive method to broaden the absorption bandwidth of polymer/fullerene‐based bulk heterojunction (BHJ) solar cells is to blend near infrared (near‐IR) sensitizers into the host system. Axial substitution of silicon phthalocyanines (Pcs) opens a possibility to modify the chemical, thermodynamic, electronic, and optical properties. Different axial substitutions are already designed to modify the thermodynamic properties of Pcs, but the impact of extending the π‐conjugation of the axial ligand on the opto‐electronic properties, as a function of the length of the alkyl spacer, has not been investigated yet. For this purpose, a novel series of pyrene‐substituted silicon phthalocyanines (SiPc‐Pys) with varying lengths of alkyl chain tethers are synthesized. The UV–vis and external quantum efficiency (EQE) results exhibit an efficient near IR sensitization up to 800 nm, clearly establishing the impact of the pyrene substitution. This yields an increase of over 20% in the short circuit current density (J _SC) and over 50% in the power conversion efficiency (PCE) for the dye‐sensitized ternary device. Charge generation, transport properties, and microstructure are studied using different advanced technologies. Remarkably, these results provide guidance for the diverse and judicious selection of dye sensitizers to overcome the absorption limitation and achieve high efficiency ternary solar cells.     

Effect of Epichloë fungal endophyte symbiosis on tall fescue to cope with flooding-derived oxygen-limited conditions depends on the host genotype

Plant and Soil - There is little information about the role of fungal endophytes on plant performance under oxygen-limited conditions. This study aimed to investigate the effect of Epichloë...     

No association between the PPARG gene and schizophrenia in a British population

It has consistently been reported that patients with schizophrenia have an increased risk of type-2 diabetes. To investigate a genetic link between these two diseases, the combined effects of the PLA2G4A, PTGS2 and PPARG genes were tested among 221 British nuclear families consisting of fathers, mothers and affected offspring with schizophrenia. A total of 10 single nucleotide polymorphisms (SNPs) were tested and the likelihood-based association analysis for nuclear families was used to analyse the genotyping data. Eight SNPs detected across the PPARG gene did not show allelic association with schizophrenia; a weak association was detected at rs2745557 in the PTGS2 locus (χ²=4.19, p=0.041) and rs10798059 in the PLA2G4A locus (χ²=4.28, p=0.039) but these associations did not survive after 10,000 permutations to correct the p-value (global p=0.246). The gene–gene interaction test did not show any evidence of either cis-phase interactions for the PLA2G4A and PTGS2 combinations or a trans-phase interaction for the PLA2G4A and PPARG combinations. The PPARG gene has been reported to be strongly associated with type-2 diabetes, but the present study did not support the hypothesis that the PPARG gene may also play an important role in the development of schizophrenia.     

Interface Design to Improve the Performance and Stability of Solution‐Processed Small‐Molecule Conventional Solar Cells

A systematic study on the effect of various cathode buffer layers on the performance and stability of solution‐processed small‐molecule organic solar cells (SMOSCs) based on tris{4‐[5‐(1,1‐dicyanobut‐1‐en‐2‐yl)‐2,2‐bithiophen‐5‐yl]phenyl}amine (N(Ph‐2T‐DCN‐Et)₃):6,6‐phenyl‐C71‐butyric acid methyl ester (N(Ph‐2T‐DCN‐Et)₃:PC₇₀BM) is presented. The power conversion efficiency (PCE) in these systems can be significantly improved from approximately 4% to 5.16% by inserting a metal oxide (ZnO) layer between the active layer and the Al cathode instead of an air‐sensitive Ba or Ca layer. However, the low work‐function Al cathode is susceptible to chemical oxidation in the atmosphere. Here, an amine group functionalized fullerene complex (DMAPA‐C₆₀) is inserted as a cathode buffer layer to successfully modify the interface towards ZnO/Ag and active layer/Ag functionality. For devices with ZnO/DMAPA‐C₆₀/Ag and DMAPA‐C₆₀/Ag cathodes the PCEs are improved from 2.75% to 4.31% and to 5.40%, respectively, compared to a ZnO/Ag device. Recombination mechanisms and stability aspects of devices with various cathodes are also investigated. The significant improvement in device performance and stability and the simplicity of fabrication by solution processing suggest this DMAPA‐C₆₀‐based interface as a promising and practical pathway for developing efficient, stable, and roll‐to‐roll processable SMOSCs.     

Regioselectivity in Sonogashira synthesis of 6-(4-nitrobenzyl)-2-phenylthiazolo[3,2-b]1,2,4-triazole: a quantum chemistry study

In the present research, the experimentally observed regioselectivity in Sonogashira synthesis of 6-(4-nitrobenzyl)-2-phenylthiazolo[3,2-b]1,2,4triazole has been modeled by means of density functional theory (DFT) employed to investigate the structural and thermochemical aspects of this synthesis in the gas and solution phases. Comparison of our calculated structural parameters of the title compound with the available X-ray crystallographical data demonstrate a reliable agreement. Then, the effect of two different solvents, DMF and ethanol, are examined via polarized continuum model calculations, showing a significant decrease in the computed values of the reaction enthalpy and free energy changes compared with the gas phase results. We have also considered two tautomeric structures of the intermediate species that it seems the mode of its intermolecular cyclization has an important role in regioselectivity of the final products. Moreover, all obtained results in the gas and solution phases also confirm that the synthesis of the title compound is thermodynamically more favorable than the other regioisomeric product. We also discuss the thermodynamical feasibility of this reaction at higher temperatures. Finally, we concentrate on the survey of substituent effect by choosing electron-withdrawing and electron-donating groups on the aryl iodide. Our calculated thermochemical data in the gas and solution phases indicate that the use of electron-withdrawing moieties is more favorable thermodynamically than electron-donating ones which has been previously concluded via the experimental elucidations.

An Efficient Solution‐Processed Intermediate Layer for Facilitating Fabrication of Organic Multi‐Junction Solar Cells

Photovoltaic tandem technology has the potential to boost the power conversion efficiency of organic photovoltaic devices. Here, a reliable and efficient fully solution‐processed intermediate layer (IML) consisting of ZnO and neutralized poly(3,4‐ethylenedioxythiophene):poly(styrenesulfonate) (PEDOT:PSS) is demonstrated for series‐connected multi‐junction organic solar cells (OSCs). Drying at 80 °C in air is sufficient for this solution‐processed IML to obtain excellent functionality and reliability, which allow the use of most of high performance donor materials in the tandem structure. An open circuit voltage (V_oc) of 0.56 V is obtained for single‐junction OSCs based on a low band‐gap polymer, while multi‐junction OSCs based on the same absorber material deliver promising fill factor values along with fully additive V_oc as the number of junctions increase. Optical and electrical simulations, which are reliable and promising guidelines for the design and investigation of multi‐junction OSCs, are discussed. The outcome of optical and electrical simulations is in excellent agreement with the experimental data, indicating the outstanding efficiency and functionality of this solution‐processed IML. The demonstration of this efficient, solution‐processed IML represents a convenient way for facilitating fabrication of multi‐junction OSCs to achieve high power conversion efficiency.     

Mutant p53 binds to estrogen receptor negative promoter via DNMT1 and HDAC1 in MDA-MB-468 breast cancer cells

DNA methylation and histone deacetylation are two epigenetic mechanisms involved in the lack of estrogen receptor (ER) expression. Our previous studies demonstrated that mutant p53 along with repression complex proteins including DNMT1, HDAC1 and MeCP2 is associated with ER-negative promoter in MDA-MB-468 cells. To elucidate the molecular mechanism of estrogen receptor 1 (ESR1) gene silencing in these cells, we down-regulated DNMT1 and HDAC1 expression using siRNAs and studied the ability of DNMT1, HDAC1, MeCP2 and p53 in binding to ESR1 promoter CpG island. Our results showed that DNMT1 or HDAC1 down-regulation disassembled the repression complex proteins and mutant p53 from ER-negative promoter. The partial demethylation of ESR1 promoter and ER re-expression in down-regulated cells supports these findings. In vivo binding studies demonstrated that mutation of p53 protein in this cell line did not affect its binding capacity to DNMT1, HDAC1 and MeCP2 proteins. Our observations suggest that not only histone deacetylase activity of HDAC1 contributes to inactivation of methylated ESR1 gene but also HDAC1 presence on ESR1 promoter is important for assembly of DNMT1 in repression complex. In addition, our data revealed that mutant p53 protein binds to the promoter of ESR1 through direct interaction with HDAC1 and indirect interaction with DNMT1, MeCP2 proteins in the ER-negative MDA-MB-468 cells.     

Evaluating Drug Resistant Mutations to HCV NS3 Protease Inhibitors in Iranian Naïve Patients

International Journal of Peptide Research and Therapeutics - Hepatitis C virus (HCV) is an important causative agent of acute and chronic hepatitis. The non-structural protein 3 (NS3) of HCV...     

Combination effect of exercise training and eugenol supplementation on the hippocampus apoptosis induced by chlorpyrifos

The aim of this study was to investigate the combination effect of exercise training and eugenol supplementation on the hippocampus apoptosis induced by CPF. 64 adult male albino rats were randomly selected and devided into eight groups of eight including: control, exercise (EXE), chlorpyrifos (CPF), Control?+?Oil (Co?+?Oil), Control?+?DMSO (Co?+?DMSO), chlorpyrifos?+?eugenol (CPF?+?Sup), chlorpyrifos?+?exercise (CPF?+?Exe) and, chlorpyrifos?+?exercise?+?eugenol (CPF?+?Exe?+?Eu). Four experimental groups received intraperitoneal injection (5 days a week) of 3.0 mg/kg body weight CPF in DMSO for 6 consecutive weeks. The exercise groups performed aerobic 5 days per week over 4 weeks. Eugenol were administered by gavage. Finally, the animals were sacrificed using CO₂ gas (a half of the rats were anesthetized with ketamine and xylazine and then perfused) to evaluate hippocampus histology and parameters. The results of this study showed that CPF injection significantly decreased BDNF, AChE and ATP in CA1 area of the hippocampus (p ? 0.05). Also, CA1 apoptosis by tunnel assay, it was found that CPF receiving groups with different dosage, showed a significant increase compared to other groups, which was confirmed by increasing cytochrome C and procaspase-3 in CPF groups (p ? 0.05). The result of this study show that 4 weeks of exercise training and eugenol supplementation does not improve the destructive effects of CPF in CA1 area of the hippocampus. As a result, it is recommended that future studies longer periods for treatment with exercise and eugenol supplementation.