Approaches to Stretchable Polymer Active Channels for Deformable Transistors

The fabrication of deformable devices has been explored by interconnecting nonstretchable unit devices with stretchable conductors or by developing stretchable unit devices consisting of all stretchable device components such as electrodes, active channels, and dielectric layers. Most researches have followed the first approach so far, and the researches based on the second approach are at the very beginning stage. This paper discusses the perspectives of the second approach, specifically focusing on the polymer semiconductor channel layers, that is expected to facilitate high density device integration in addition to large area devices including polymer solar cells and light-emitting diodes. Three different routes are suggested as separate sections according to the principles imparting stretchability to polymer semiconductor layers: structural configurations of rigid semiconductors, two-dimensional network structure of semiconductors on elastomer substrates, and ductility enhancement of semiconductor films. Each section includes two subsections divided by the methodological difference. This Perspective ends with discussion on the future works for the routes and the challenges related to other device components.112417Ysciescopu

Aerobic Copper-Promoted Oxidative Dehydrosulfurative Carbon-Oxygen Cross-Coupling of 3,4-Dihydropyrimidine-1: H -2-Thiones With Alcohols

An aerobic Cu-promoted oxidative dehydrosulfurative carbon-oxygen cross-coupling of 3,4-dihydropyrimidin-1H-2-thiones (DHPMs) with both aliphatic and aromatic alcohols is described. Together with the ready availability of DHPMs and both alcohols, the method furnishes facile access to biologically valuable 2-alkoxypyrimidines with rapid diversification

High performance gas sensor platform based on integrated sensing mechanisms

We introduce a gas sensor platform consisting of resistive sensor, thin film transistor (TFT) type sensor, and Si-based field effect transistor (FET) type sensor fabricated on the same wafer. The FET type sensor has a horizontal floating gate interdigitated with the control gate. The schematic structures of these gas sensors are shown in Fig. 1. These gas sensors can be fabricated using only 5 masks. The sensing layer of these sensors is a 15nm thick n-type ZnO film prepared using atomic layer deposition (ALD) in the final process step. Although these sensors have the same sensing material, they have different sensing characteristics because of different sensing mechanisms. Our group has reported the studies of resistive- and FET-type gas sensors having ALD ZnO sensing layer previously [1], [2]. Fig. 2 shows the transfer (I-V) characteristics of these sensors. These sensors have different sensing characteristics when exposed to 500 ppb of oxidizing gas, NO2. When exposed to NO2 gas, the currents of resistive- and TFT-type gas sensors are decreased [2]. On the other hand, the drain current of the FET-type gas sensor increases when exposed to NO2 gas [1], [2]. As a result, the difference in response of these sensors can be used as a fingerprint to more accurately detect the target gas in the gas sensor platform composed of three types of gas sensors. Please click Additional Files below to see the full abstract

Recovery of off-state stress-induced damage in FET-type gas sensor using self-curing method

The need for high-performance gas sensors is driven by concerns over indoor and outdoor air quality, and industrial gas leaks. Due to their structural diversity, vast surface area, and geometric tunability, metal oxides show significant potential for the development of gas sensing systems. Despite the fact that several previous reports have successfully acquired a suitable response to various types of target gases, it remains difficult to maintain the reliability of metal oxide-based gas sensors. In particular, the degradation of the sensor platform under repetitive operation, such as off-state stress (OSS) causes significant reliability issues. We investigate the impact of OSS on the gas sensing performances, including response, low-frequency noise, and signal-to-noise ratio of horizontal floating-gate field-effect-transistor (FET)-type gas sensors. The 1/f noise is increased after the OSS is applied to the sensor because the gate oxide is damaged by hot holes. Therefore, the SNR of the sensor is degraded by the OSS. We applied a self-curing method based on a PN-junction forward current at the body–drain junction to repair the damaged gate oxide and improve the reliability of the sensor. It has been demonstrated that the SNR degradation caused by the OSS can be successfully recovered by the self-curing method

Tandem Dehydrogenation/Oxidation/Oxidative Cyclization Approach to Wrightiadione and Its Derivatives

Wrightiadione contains a unique tetracyclic isoflavone moiety and has been shown to exhibit a broad range of biological activities. An efficient and straightforward synthetic method for generating the molecular complexity of wrightiadione was developed through three-step tandem dehydrogenation/oxidation/oxidative cyclization reactions with a Pd/Cu catalytic system. This unprecedented one-pot route utilizes a broad range of substrates, providing a convenient and powerful synthetic tool for accessing naturally occurring tetracyclic isoflavone wrightiadione and its nitrogen-containing derivatives. © 2015 American Chemical Society1771sciescopu

Selective and potent small-molecule inhibitors of PI3Ks

Class I PI3Ks are composed of four catalytic subunit variants (p110, p110, p110 and p110). The PI3K pathway is among the most frequently activated pathways in many diseases, and has emerged as an attractive target for drug development, in particular for the treatment of many human cancers including breast, prostate, ovarian, gastric, colon and hepatocellular cancers. One of the challenges in the discovery of drugs that target kinases is designing small-molecule inhibitors that are sufficiently selective to minimize off-target activity and reduce the risk of potential toxicity. This review explores the current landscape of PI3K-selective inhibitor development and highlights recent advances in achieving selectivity for PI3Ks over other protein kinases, with an emphasis on available structural information.110101sciescopu

Strategies to overcome acquired resistances conferred by mutations in the kinase domain of EGFR

Deregulation of EGFR is involved in the development of many cancers. The inhibition of EGFR kinase activity has been clinically validated as a promising approach for the treatment of non-small-cell lung cancer (NSCLC). However, all NSCLC patients who initially benefited from first-generation EGFR inhibitors eventually develop drug resistance. A point mutation at the gatekeeper position, T790M in EGFR kinase domain accounts for more than 50% of acquired resistance. Therefore, second- and third-generation EGFR inhibitors have been developed to overcome the resistance conferred by the gatekeeper mutation. This review has highlighted recent advances in overcoming acquired resistance for the development of each generation of EGFR inhibitors along with their potential issues, and urgent quest for the development of new generation of EGFR inhibitors. © 2016 Future Science Ltd1341sciescopu

Discovery of wrightiadione as a novel template for the TrkA kinase inhibitors

Enzymatic kinase assays and docking simulation studies have shown that the natural product wrightiadione displays inhibitory activity toward TrkA and PLK3. In this study, the template of wrightiadione served as a starting point for Trk inhibitor development campaigns. Molecular simulation provided structural insights for the design of derivatives that were efficiently generated by our recently developed 3-step tandem synthetic approach, resulting in the discovery of compound 2h with biochemical potency at the single-digit micromolar level. © 2015 Elsevier Ltd. All rights reserved1111sciescopu

Rh(iii)-catalyzed direct C-H/C-H cross-coupling of quinones with arenes assisted by a directing group: Identification of carbazole quinones as GSKβ inhibitors

Rh-catalyzed direct C-H/C-H cross-coupling reaction of various (hetero)arenes with quinones is developed. This protocol is effective for a broad range of both quinone and arene substrates and a wide range of directing groups for this reaction, affording structurally diverse aryl-substituted quinones with high synthetic utility. Moreover, the present synthetic route allowed for the rapid construction of the carbazole quinone moiety that was identified as a new inhibitor scaffold for GSKβ. This journal is © The Royal Society of Chemistry 2015119211sciescopu

Recommendation system with minimized transaction data

This paper deals with the recommendation system in the so-called user-centric payment environment where users, i.e., the payers, can make payments without providing self-information to merchants. This service maintains only the minimum purchase information such as the purchased product names, the time of purchase, the place of purchase for possible refunds or cancellations of purchases. This study aims to develop AI-based recommendation system by utilizing the minimum transaction data generated by the user-centric payment service. First, we developed a matrix-based extrapolative collaborative filtering algorithm based on open transaction data. The recommendation methodology was verified with the real transaction data. Based on the experimental results, we confirmed that the recommendation performance is satisfactory only with the minimum purchase information