Synthesis of n-type semiconducting polymer consisting of benzodipyrrolidone and thieno-[3,4-c]-pyrrole-4,6-dione via CH direct arylation

Direct arylation polycondensation of 3,​7-​bis(4-​bromophenyl)​-​1,​5-​bis(2-​octyldodecyl)​benzo[1,​2-​​b:4,​5-​b\u27]​dipyrrole-​2,​6(1H,​5H)​-​dione with 5-(2-ethylhexyl)-thieno-[3,4-c]-pyrrole-4,6-dione gave the corresponding benzodipyrrolidone-based conjugated polymer with a molecular weight of 147,000 in 92% yield. The optical and thermal properties of the polymer were evaluated. The polymer showed n-type semiconducting behavior in organic field-effect transistors with an electron mobility of 1.3 ± 0.2 × 10−3 cm2 V−1 s−1

Facile one-pot access to π-conjugated polymers via sequential bromination/direct arylation polycondensation

The synthesis of π-conjugated polymers starting from unfunctionalized aromatic monomers via sequential bromination/direct arylation polycondensation was investigated. The developed protocol provides a step-economical access to the polymers in a one-pot fashion, without the need for prior preparation and purification of dibrominated aromatic monomers or organometallic monomers. Benzyltrimethylammonium tribromide was effective for the bromination of 10-(2-octyldodecyl)phenothiazine and 4,4′-didodecyl-2,2′-bithiophene, and the obtained dibrominated aromatic monomers were used for the subsequent direct arylation polycondensation without isolation and purification. The direct arylation polycondensation reaction yielded the corresponding donor–acceptor-type π-conjugated polymers in moderate to good yields. The sequential protocol was also applicable to the synthesis of poly(3-hexylthiophene-2,5-diyl) from 3-hexylthiophene. The obtained polymers served as semiconducting materials in organic light-emitting diodes and organic photovoltaics

MicroRNA-133 regulates the expression of GLUT4 by targeting KLF15 and is involved in metabolic control in cardiac myocytes

GLUT4 shows decreased levels in failing human adult hearts. We speculated that GLUT4 expression in cardiac muscle may be fine-tuned by microRNAs. Forced expression of miR-133 decreased GLUT4 expression and reduced insulin-mediated glucose uptake in cardiomyocytes. A computational miRNA target prediction algorithm showed that KLF15 is one of the targets of miR-133. It was confirmed that over-expression of miR-133 reduced the protein level of KLF15, which reduced the level of the downstream target GLUT4. Cardiac myocytes infected with lenti-decoy, in which the 3′UTR with tandem sequences complementary to miR-133 was linked to the luciferase reporter gene, had decreased miR-133 levels and increased levels of GLUT4. The expression levels of KLF15 and GLUT4 were decreased at the left ventricular hypertrophy and congestive heart failure stage in a rat model. The present results indicated that miR-133 regulates the expression of GLUT4 by targeting KLF15 and is involved in metabolic control in cardiomyocytes

Spin-triplet superconductivity due to antiferromagnetic spin-fluctuation in Sr_2RuO_4

A mechanism leading to the spin-triplet superconductivity is proposed based on the antiferromagnetic spin fluctuation. The effects of anisotropy in spin fluctuation on the Cooper pairing and on the direction of d vector are examined in the one-band Hubbard model with RPA approximation. The gap equations for the anisotropic case are derived and applied to Sr_2RuO_4. It is found that a nesting property of the Fermi surface together with the anisotropy leads to the triplet superconductivity with the d=z(sin{k_x}\pm isin{k_y}), which is consistent with experiments.Comment: 4 pages, 3 eps figures, revte

Emission from Charge-Transfer States in Bulk Heterojunction Organic Photovoltaic Cells Based on Ethylenedioxythiophene-Fluorene Polymers

We investigated the electroluminescence (EL) from charge-transfer (CT) in the interface state of PEDOTF/PC70BM, known to be empirically related to Voc, to elucidate a difference in Voc of 0.24 V in bulk heterojunction (BHJ) organic photovoltaic cells (OPVs) based on two polymers (H-PEDOTF and S-PEDOTF with a high and low molecular weight, respectively) having almost the same HOMO energy levels. The difference in the energies of CT EL peaks is relatively small (0.06 eV) compared to the difference in the Vocs. Consequently, we mainly attribute the excessive loss of Voc in S-PEDOTF-based OPVs to a trap assisted recombination mechanism

The renin–angiotensin system promotes arrhythmogenic substrates and lethal arrhythmias in mice with non-ischaemic cardiomyopathy

[Aims]The progression of pathological left ventricular remodelling leads to cardiac dysfunction and contributes to the occurrence of malignant arrhythmias and sudden cardiac death. The underlying molecular mechanisms remain unclear, however. Our aim was to examine the role of the renin–angiotensin system (RAS) in the mechanism underlying arrhythmogenic cardiac remodelling using a transgenic mouse expressing a cardiac-specific dominant-negative form of neuron-restrictive silencer factor (dnNRSF-Tg). This mouse model exhibits progressive cardiac dysfunction leading to lethal arrhythmias. [Methods and results]Subcutaneous administration of aliskiren, a direct renin inhibitor, significantly suppressed the progression of pathological cardiac remodelling and improved survival among dnNRSF-Tg mice while reducing arrhythmogenicity. Genetic deletion of the angiotensin type 1a receptor (AT1aR) similarly suppressed cardiac remodelling and sudden death. In optical mapping analyses, spontaneous ventricular tachycardia (VT) and fibrillation (VF) initiated by breakthrough-type excitations originating from focal activation sites and maintained by functional re-entry were observed in dnNRSF-Tg hearts. Under constant pacing, dnNRSF-Tg hearts exhibited markedly slowed conduction velocity, which likely contributes to the arrhythmogenic substrate. Aliskiren treatment increased conduction velocity and reduced the incidence of sustained VT. These effects were associated with suppression of cardiac fibrosis and restoration of connexin 43 expression in dnNRSF-Tg ventricles. [Conclusion]Renin inhibition or genetic deletion of AT1aR suppresses pathological cardiac remodelling that leads to the generation of substrates maintaining VT/VF and reduces the occurrence of sudden death in dnNRSF-Tg mice. These findings demonstrate the significant contribution of RAS activation to the progression of arrhythmogenic substrates

Synthesis of conjugated polymers via direct C–H/C–Cl coupling reactions using a Pd/Cu binary catalytic system

Direct arylation polycondensation is regarded as an efficient synthetic method for conjugated polymers. This methodology is difficult to apply to dichloroaryl monomers because of the low reactivity of the C–Cl bonds compared to that of the C–Br bonds in dibromoaryl monomers, which have been widely used in direct arylation polycondensation. In this research, direct arylation polycondensation of dichloroaryl monomers was achieved by the use of a Pd/Cu binary catalytic system. Optimisation of the molar ratio of the Pd and Cu catalyst resulted in the formation of high-molecular-weight polymers in good yields. Structural defects of the polymer at the terminal unit were minimised by logical choice of the monomer ratio on the basis of the reaction mechanism. The obtained polymer with relatively low structural defects showed a higher quantum efficiency of photoluminescence and electroluminescence than that of the polymer with irregular terminal structures