Synthesis of triphenylamine-based thiophene-(N-aryl)pyrrole-thiophene dyes for dye-sensitized solar cell applications

Two new triphenylamine-based metal-free organic dyes (TPTDYE-1 and TPTDYE-2) containing 1-(2,6-diisopropylphenyl)-2,5-di(2-thienyl)pyrrole as a new π-conjugated chromophore were synthesized for dye-sensitized solar cell (DSSC) applications. TPTDYE-1 containing three donor groups around the acceptor group was found to show relatively narrow absorption band from 300 nm to 470 nm while TPTDYE-2 having extended π–π delocalization between the donor and acceptor group showed broad absorption band from 300 nm to 550 nm. The electrochemical studies indicate that the HOMO–LUMO energy gap of TPTDYE-1 is considerably wider than that of TPTDYE-2. The dye-sensitized solar cell performance of each dye was investigated, and the TPTDYE-2-sensitized cell was found to show a maximum monochromatic incident photon-to-current conversion efficiency (IPCE) of 75%, a short-circuit photocurrent density (J_sc) of 13.50 mA/cm², an open-circuit voltage (V_oc) of 0.72 V, and a fill factor (FF) of 0.69, corresponding to an overall conversion efficiency of 6.71% under simulated AM 1.5 irradiation (100 mW/cm²). Under the same condition the TPTDYE-1-sensitized cell showed the same IPCE value of 75% with a promising conversion efficiency of 6.00%, a J_sc of 11.11 mA/cm², a V_oc of 0.76 V, and a FF of 0.71.     

Comparative resin kinetics using in situ fluorescence measurements

The aminolysis of a novel activated ester resin was utilized for kinetic study via continuous in situ fluorescence measurements. A variety of resin compositions (polystyrene, JandaJel, ArgoPore, TentaGel, NovaGel, and PEGA) and solvents (dimethylformamide, acetonitrile, tetrahydrofuran, 1,2-dichlorethane, and toluene) were tested to compare their effects on the reaction rate. A linear relationship between the reaction rate and (solvent polarity x swelling of resin) was elucidated for the aminolysis reaction.     

CDK5-dependent inhibitory phosphorylation of Drp1 during neuronal maturation

Mitochondrial functions are essential for the survival and function of neurons. Recently, it has been demonstrated that mitochondrial functions are highly associated with mitochondrial morphology, which is dynamically changed by the balance between fusion and fission. Mitochondrial morphology is primarily controlled by the activation of dynamin-related proteins including dynamin-related protein 1 (Drp1), which promotes mitochondrial fission. Drp1 activity is regulated by several post-translational modifications, thereby modifying mitochondrial morphology. Here, we found that phosphorylation of Drp1 at serine 616 (S616) is mediated by cyclin-dependent kinase 5 (CDK5) in post-mitotic rat neurons. Perturbation of CDK5 activity modified the level of Drp1^S616 phosphorylation and mitochondrial morphology in neurons. In addition, phosphorylated Drp1^S616 preferentially localized as a cytosolic monomer compared with total Drp1. Furthermore, roscovitine, a chemical inhibitor of CDKs, increased oligomerization and mitochondrial translocation of Drp1, suggesting that CDK5-dependent phosphorylation of Drp1 serves to reduce Drp1''s fission-promoting activity. Taken together, we propose that CDK5 has a significant role in the regulation of mitochondrial morphology via inhibitory phosphorylation of Drp1^S616 in post-mitotic neurons.     

Enhanced interfacial adhesion,mechanical, and thermal properties of natural flour-filled biodegradable polymer bio-composites

This study examined the interfacial adhesion, mechanical, and thermal properties of compatibilizing agent-treated and non-treated biocomposites as a function of the type of compatibilizing agent. The tensile strength, interfacial adhesion, and heat deflection temperature (HDT) of maleic anhydride-grafted poly(butylene succinate) (PBS-MA) and maleic anhydride-grafted poly(lactic acid) (PLA-MA)-treated biocomposites are greater than those of untreated maleic anhydride-grafted poly(styrene-b-ethylene-co-butylene-b-styrene) triblock copolymer (SEBS-MA) and maleic anhydride-grafted polypropylene (MAPP)-treated biocomposites. The storage modulus (E′) values and the tan δ_max temperatures (T _g) of PBS-MA and PLA-MA-treated biocomposites were slightly higher than that of the untreated biocomposites.     

A Diels-Alder route to angularly functionalized bicyclic structures

A Diels-Alder-based route to trans-fused angularly functionalized bicyclic structures has been developed. This transformation features the use of a tetrasubstituted dienophile in the cycloaddition step.