Impact of Noncovalent Sulfur–Fluorine Interaction Position on Properties,Structures, and Photovoltaic Performance in Naphthobisthiadiazole‐Based Semiconducting Polymers

Controlling the energetics and backbone order of semiconducting polymers is essential for the performance improvement of polymer‐based solar cells. The use of fluorine as the substituent for the backbone is known to effectively deepen the molecular orbital energy levels and coplanarize the backbone by noncovalent interactions with sulfur of the thiophene ring. In this work, novel semiconducting polymers are designed and synthesized based on difluoronaphthobisthiadiazole (FNTz) as a new family of naphthobisthiadiazole (NTz)–quaterthiophene copolymer systems, which are one of the highest performing polymers in solar cells. The effect of the fluorination position on the energetics and backbone order is systematically studied. It is found that the dependence of the solar cell fill factor on the active layer thickness is very sensitive to the fluorination position. It is thus further investigated and discussed how the structural features of the polymers influence the photovoltaic parameters as well as the diode characteristics and bimolecular recombination. Further, the polymer with fluorine on both the naphthobisthiadiazole and quaterthiophene moieties exhibits a quite high power conversion efficiency of 10.8% in solar cells in combination with a fullerene. It is believed that the results would offer new insights into the development of semiconducting polymers.     

Antimicrobial activity and secondary structure of a novel peptide derived from ovalbumin

A novel antimicrobial peptide derived from ovalbumin has been discovered. First, the peptide fragment RKIKVYLPRMK (TK9.1) was identified based on computerized predictions of the secondary structure of peptides in a protein data bank. Using HeliQuest, the sequence was developed into RKIKRYLRRMI (TK9.1.3), which was synthesized using Fmoc‐solid phase peptide synthesis, and found to have strongly antimicrobial activity against Gram‐positive and Gram‐negative bacteria, and fungi but not cytotoxic to HeLa cells and hemolysis in mouse red blood cells. Although ovalbumin itself does not have an antibacterial activity, our results suggest that it may supply the organisms that consume it with antimicrobial peptides, in support of their immunodefence.     

Redescription of Lepadichthys coccinotaenia Regan 1921 and description of Lepadichthys trishula sp. nov. from southern Japan (Gobiesocidae: Diademichthyinae)

Ichthyological Research - Lepadichthys coccinotaenia Regan 1921 (Gobiesocidae: Diademichthyinae) is redescribed on the basis of 60 specimens, including the holotype, and a new species of...     

SCF-Fbxo42 promotes synaptonemal complex assembly by downregulating PP2A-B56

Meiosis creates genetic diversity by recombination and segregation of chromosomes. The synaptonemal complex assembles during meiotic prophase I and assists faithful exchanges between homologous chromosomes, but how its assembly/disassembly is regulated remains to be understood. Here, we report how two major posttranslational modifications, phosphorylation and ubiquitination, cooperate to promote synaptonemal complex assembly. We found that the ubiquitin ligase complex SCF is important for assembly and maintenance of the synaptonemal complex in Drosophila female meiosis. This function of SCF is mediated by two substrate-recognizing F-box proteins, Slmb/βTrcp and Fbxo42. SCF-Fbxo42 down-regulates the phosphatase subunit PP2A-B56, which is important for synaptonemal complex assembly and maintenance.     

Microwave irradiation for fixation and immunostaining of endothelial cells in situ

Using microwave irradiation during tissue fixation and immunostaining reduces sample preparation time and facilitates penetration of fixatives and antibody solutions into the tissues. This results in improved fixation and reduction of non-specific binding of antibodies, respectively. Experimental analyses of endothelial cells in blood vessels in situ have been limited because of the difficulty of tissue preparation. We report here a technique using intermittent microwave irradiation for blood vessel fixation and immunostaining the fixed tissues. Intermittent microwave irradiation during fixation reduced blood vessel contraction and resulted in well preserved morphology of blood vessels, especially the endothelial cells. Microwave irradiation also reduced non-specific binding of fluorescein-labeled antibodies. These microwave irradiation-assisted techniques are useful for analysis of endothelial cell function and for pathological study of blood vessels in situ.