The present paper describes the preparation and characterization of stable aqueous dispersions of poly (3-hexylthiophene) (P3HT) by a precipitation method. P3HT was first synthesized by oxidative polymerization of 3HT with iron(III) chloride as an oxidant. Number-average molecular weight (M n ) of P3HT increased with an increase in 3HT concentration. Colloidal particles were prepared by adding a tetrahydrofuran (THF) solution of P3HT into a large amount of distilled water. TEM observations showed that the particle size increased with an increase in the concentration and M n of P3HT. The size of the particles was in the range of 50 to 600 nm. The spectral features of the aqueous dispersions were investigated by means of UV-vis spectroscopy. P3HT provided the -Ã absorption band at 436 nm in THF. On the other hand, the dispersions brought about a bathochromic shift of the bands and a larger red shift was observed as the polymer concentration became higher, indicating that P3HT would take a well-stacked structure in the particles. Temperature dependence of UV-vis absorption spectra for P3HT aqueous dispersions was also studied in the temperature range of 0 to 80 C, which revealed that P3HT in the dispersed state showed a thermochromism similar to that of P3HT in THF.KEY WORDS: Polythiophene / -Conjugated Polymer / Poly(3-hexylthiophene) / Colloidal Particle / Conducting Polymer / Precipitation Method / Thermochromism / Poly(3-hexylthiophene) (P3HT) is a subject of extensive study because of its solubility, fusibility, and environmental stability.1 P3HT also exhibits unique properties such as thermochromism and solvatochromism. [2][3][4][5][6] This functional polymer is viewed as potentially useful materials in fieldeffect transistors, optical and electronic sensors, light-emitting devices, nonlinear optical materials, etc. 7-9Our attention has focused on colloidal dispersions of P3HT particles. Colloidal particles are of great importance due to their interesting physical properties as well as their potential technological applications.10,11 Several attempts have been made so far to produce P3HT particles. Yamamoto et al. employed a reprecipitation method to prepare colloidal dispersions of P3HT. Methanol, which is a poor solvent for P3HT, was added to the CHCl 3 solution of P3HT, resulting in the formation of P3HT particles. 12,13 Takeuchi and Kobashi also investigated in detail the kinds of poor solvents and clarified the precipitation conditions for improved yields. 14 Furthermore, it has been reported that the use of a nonionic surfactant, Tween 80, provided stable aqueous dispersions of P3HT. 15To our knowledge, few reports on water self-dispersible P3HT particles have been published. 15 There is hence a lack of information about colloidal properties of P3HT water dispersions, such as particle size, particle morphology, optical property, etc. Development and characterization of such dispersions are of great significance from an environmental as well as industrial aspect. The purpose of the present study is to de...
A frog retinal protein named s26 is a 26-kDa protein found during purification of S-modulin in frog retina (Kawamura, S. (1992) Photochem. Photobiol. 56, 1173-1180). To identify its role in frog retina, first s26 was purified to nearly homogeneity with three chromatographical steps. Based on the partial amino acid sequences of the proteolysed fragments of s26, we isolated cDNAs that encode s26. The analysis of its amino acid sequence revealed that s26 is an S-modulin-like protein, while it shows higher homology to visinin. Visinin is a Ca 2؉ -binding protein reported to be present in chicken cones, but its localization in the retina had been a subject in dispute. The present study showed that s26 is present in cone photoreceptors. The study also showed that s26 inhibits phosphorylation of rhodopsin after a light flash at high Ca 2؉ concentrations as S-modulin does. From these results, we concluded that s26 is a cone homologue of S-modulin. The result is consistent with the idea that each type of photoreceptors expresses each cell-type specific version of phototransduction proteins.
Nuclear factor I A (NFIA) is a transcription factor that belongs to the NFI family. Truncating variants or intragenic deletion of the NFIA gene are known to cause the human neurodevelopmental disorder known as NFIA‐related disorder, but no patient heterozygous for a missense mutation has been reported. Here, we document two unrelated patients with typical phenotypic features of the NFIA‐related disorder who shared a missense variant p.Lys125Glu (K125E) in the NFIA gene. Patient 1 was a 6‐year‐old female with global developmental delay, corpus callosum anomaly, macrocephaly, and dysmorphic facial features. Patient 2 was a 14‐month‐old male with corpus callosum anomaly and macrocephaly. By using Drosophila and zebrafish models, we functionally evaluated the effect of the K125E substitution. Ectopic expression of wild‐type human NFIA in Drosophila caused developmental defects such as eye malformation and premature death, while that of human NFIA K125E variant allele did not. nfia‐deficient zebrafish embryos showed defects of midline‐crossing axons in the midbrain/hindbrain boundary. This impairment of commissural neurons was rescued by expression of wild‐type human NFIA, but not by that of mutant variant harboring K125E substitution. In accordance with these in vivo functional analyses, we showed that the K125E mutation impaired the transcriptional regulation of HES1 promoter in cultured cells. Taken together, we concluded that the K125E variant in the NFIA gene is a loss‐of‐function mutation.
Copy number variants (CNVs) are significant causes of rare and undiagnosed diseases. Parallel detection of single nucleotide variants (SNVs) and CNVs with exome analysis, if feasible, would shorten the diagnostic closure in a timely manner. We validated such "parallel" approach through a cohort study of 791 undiagnosed patients. In addition to routine exome analysis, we applied an innovative algorithm EXCAVA-TOR2 which enhances sensitivity by paradoxically exploiting read depth data that covers nonexonic regions where baits were not originally intended to hybridize. About 48 patients had copy number variations, 42 deletions, and 6 duplications with a resolution of 0.51-14.7 mega base pairs. Importantly from a clinical standpoint, we identified three patients with "dual diagnosis" due to concurrent pathogenic CNV and SNV. We suggest "hitting two birds with one stone" approach to exome data is an efficient strategy in deciphering undiagnosed patients and may well be considered as a first-tier genetic test.
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