Correlating the structures and photovoltaic properties in phase-separated blends of conjugated donor polymers and acceptors

The power conversion efficiency of polymer solar cells strongly depends on the microscale morphology of the interpenetrating network structures between the polymer donor and acceptor materials. Therefore, it is essential to understand the relationship between photovoltaic properties and phase-separated structures in the blend active layer. Here, we discuss the relationship between charge generation and collection and phase-separated structures, which was analyzed by a ternary phase diagram for polymer solar cells based on blends of a thiophene-based conjugated polymer donors and the following different acceptors: a fullerene derivative, a nonfullerene acceptor, and a conjugated polymer acceptor. By considering the ternary phase diagram based on the Flory–Huggins interaction parameters, we discuss the binodal point and acceptor volume fraction in the mixed phase in each material combination. Furthermore, we suggest strategies for improving the efficiency of polymer solar cells according to the molecular weight of acceptor materials. These findings will provide a guideline for developing highly efficient polymer solar cells

〓

本稿では, マイクロカプセル化法としての噴霧乾燥法の最近の進歩を解説する。初めに・噴霧造粒法によるマイクロカプセルの製法を概説し・次いで噴霧造粒法により製したマイクロカプセルの応用について説明する。ここで取りあげた応用実例は, 1)芯物質の放出速度の調節, 2)芯物質の保護と安定化, 3)液状物質の粉末化及びその他の応用, である。最後に噴霧乾燥法の最近のトピックスとして,1)壁膜材の熱変性, 2)芯物質の多形, 3)反応を伴う乾燥操作, について著者等の研究を中心にして説明する。In the present article, the recent advances of spray drying technique for microencapsulation are reviewed. At first, the preparation methods of microcapsule by spray agglomeration are introduced and the applications of the resultant microcapsule are described. As a practical application of the microcapsule, 1) controlled release of encapsulated substance, 2) protection and stabilization of encapsulated substance, 3) transformation of liquid substance into solid powder and miscellaneous are considered. Finally, as a recent topic on spray drying, 1) thermal denaturalization of wall material, 2) polymorphism of encapsulated substance, and 3) drying process with reaction are explained by referring mainly to the present authors\u27 studies

Anisotropic Optical Conductivity Accompanied by a Small Energy Gap in One-Dimensional Thermoelectric Telluride Ta4SiTe4

We investigated the optical properties of single crystals of one-dimensional telluride Ta4SiTe4, which shows high thermoelectric performance below room temperature. Optical conductivity estimated from reflectivity spectra indicates the presence of a small energy gap of 0.1-0.15 eV at the Fermi energy. At the lowest energy, optical conductivity along the Ta4SiTe4 chain is an order of magnitude higher than that perpendicular to this direction, reflecting the anisotropic electron conduction in Ta4SiTe4. These results indicate that coexistence of a very small band gap and anisotropic electron conduction is a promising strategy to develop a high-performance thermoelectric material for low temperature applications.Comment: 6 pages, 4 figure

Is Preoperative Magnetic Resonance Imaging in a Daily Clinical Setting Useful to Evaluate Tumor Invasion Beyond the Pseudocapsule in Renal Cell Carcinoma?

Background: We wanted to clarify whether preoperative magnetic resonance imaging (MRI) in the clinical setting can evaluate the pathologic pseudocapsule (PC) morphology with high accuracy in renal cell carcinoma (RCC). Methods: We retrospectively analyzed 34 consecutive patients who underwent MRI (1.5 or 3.0T, 5 mm slices) prior to partial nephrectomy (PN) for RCC at our institution between January 2010 and December 2019. First, the correlation between PC morphology (complete or incomplete) and tumor infiltration to the renal parenchyma was examined as pathologic validation. Second, the concordance rate of PC morphology between pathologic tissue and preoperative MRI was evaluated as radiologic validation. Third, risk factor for renal parenchymal invasion in RCC was analyzed. Results: In the pathologic validation, parenchymal invasion rates were 11% and 28% in the “complete PC” and “incomplete PC” groups, respectively. In the radiologic validation, pathological PC morphology could be diagnosed on preoperative MRI in 17 patients (50.0%). “None PC” on MRI had the lowest positive predictive value (PPV) (0%), “partial PC” on MRI had a good PPV (76.5%), “complete PC” on MRI had a relatively low PPV (33.3%). Unfortunately, these data were insufficient for diagnostic accuracy. As risk factor for renal parenchymal invasion in RCC, only pathologic subtype (non-clear cell) was found to have significant differences in the multivariate analysis. Conclusion: The results of this study suggest that renal tumors with pathologically incomplete PC have a high possibility of renal parenchymal invasion. However, it is currently difficult to accurately evaluate pathologic PC morphology by preoperative MRI in the clinical setting

A Method for Similarity Search of Genomic Positional Expression Using CAGE

With the advancement of genome research, it is becoming clear that genes are not distributed on the genome in random order. Clusters of genes distributed at localized genome positions have been reported in several eukaryotes. Various correlations have been observed between the expressions of genes in adjacent or nearby positions along the chromosomes depending on tissue type and developmental stage. Moreover, in several cases, their transcripts, which control epigenetic transcription via processes such as transcriptional interference and genomic imprinting, occur in clusters. It is reasonable that genomic regions that have similar mechanisms show similar expression patterns and that the characteristics of expression in the same genomic regions differ depending on tissue type and developmental stage. In this study, we analyzed gene expression patterns using the cap analysis gene expression (CAGE) method for exploring systematic views of the mouse transcriptome. Counting the number of mapped CAGE tags for fixed-length regions allowed us to determine genomic expression levels. These expression levels were normalized, quantified, and converted into four types of descriptors, allowing the expression patterns along the genome to be represented by character strings. We analyzed them using dynamic programming in the same manner as for sequence analysis. We have developed a novel algorithm that provides a novel view of the genome from the perspective of genomic positional expression. In a similarity search of expression patterns across chromosomes and tissues, we found regions that had clusters of genes that showed expression patterns similar to each other depending on tissue type. Our results suggest the possibility that the regions that have sense–antisense transcription show similar expression patterns between forward and reverse strands