Controlling Polarity of Organic Bulk Heterojunction Field-Effect Transistors via Solvent Additives

The effect of additives such as 1,8-diiodooctane (DIO) and 1-chloronaphthalene (CN) on the electronic structures, charge transport and phase separation of small-molecule-based bulk heterojunction (BHJ) films was investigated. Charge transport properties of the BHJ layers significantly changed via the introduction of additives, even though the molecular energy levels remained unchanged. X-ray photoelectron microscopy (XPM) images show the distribution of each phase of the blend films upon the use of additives. The CN additive, in particular, results in a well-percolated network through the active layer

β‑Alkyl substituted Dithieno[2,3‑<i>d</i>;2′,3′<i>-d</i>′]benzo[1,2‑<i>b</i>;4,5‑<i>b</i>′]dithiophene Semiconducting Materials and Their Application to Solution-Processed Organic Transistors

A novel highly π-extended heteroacene with four symmetrically fused thiophene-ring units and solubilizing substituents at the terminal β-positions on the central ring, dithieno­[2,3-<i>d</i>;2′,3′<i>-d</i>′]­benzo­[1,2-<i>b</i>;4,5-<i>b</i>′]­dithiophene (DTBDT) was synthesized via intramolecular electrophilic coupling reaction. The α-positions availability in the DTBDT motif enables the preparation of solution-processable DTBDT-based polymers such as <b>PDTBDT</b>, <b>PDTBDT-BT</b>, <b>PDTBDT-DTBT</b>, and <b>PDTBDT-DTDPP</b>. Even with its highly extended acene-like π-framework, all polymers show fairly good environmental stability of their highest occupied molecular orbitals (HOMOs) from −5.21 to −5.59 eV. In the course of our study to assess a profile of semiconductor properties, field-effect transistor performance of the four DTBDT-containing copolymers via solution-process is characterized, and <b>PDTBDT-DTDPP</b> exhibits the best electrical performance with a hole mobility of 1.70 × 10^–2 cm² V^–1 s^–1. <b>PDTBDT-DTDPP</b> has a relatively smaller charge injection barrier for a hole from the gold electrodes and maintains good coplanarity of the polymer backbone, indicating the enhanced π–π stacking characteristic and charge carrier transport. The experimental results demonstrate that our molecular design strategy for air-stable, high-performance organic semiconductors is highly promising

Fibroblast Growth Factor-2 Induced by Enriched Environment Enhances Angiogenesis and Motor Function in Chronic Hypoxic-Ischemic Brain Injury

<div><p>This study aimed to investigate the effects of enriched environment (EE) on promoting angiogenesis and neurobehavioral function in an animal model of chronic hypoxic-ischemic (HI) brain injury. HI brain damage was induced in seven day-old CD-1® mice by unilateral carotid artery ligation and exposure to hypoxia (8% O2 for 90 min). At six weeks of age, the mice were randomly assigned to either EE or standard cages (SC) for two months. Rotarod, forelimb-use asymmetry, and grip strength tests were performed to evaluate neurobehavioral function. In order to identify angiogenic growth factors regulated by EE, an array-based multiplex ELISA assay was used to measure the expression in frontal cortex, striatum, and cerebellum. Among the growth factors, the expression of fibroblast growth factor-2 (FGF-2) was confirmed using western blotting. Platelet endothelial cell adhesion molecule-1 (PECAM-1) and α-smooth muscle actin (α-SMA) were also evaluated using immunohistochemistry. As a result, mice exposed to EE showed significant improvements in rotarod and ladder walking performances compared to SC controls. The level of FGF-2 was significantly higher in the frontal cortex of EE mice at 8 weeks after treatment in multiplex ELISA and western blot. On the other hand, FGF-2 in the striatum significantly increased at 2 weeks after exposure to EE earlier than in the frontal cortex. Expression of activin A was similarly upregulated as FGF-2 expression pattern. Particularly, all animals treated with FGF-2 neutralizing antibody abolished the beneficial effect of EE on motor performance relative to mice not given anti-FGF-2. Immunohistochemistry showed that densities of α-SMA⁺ and PECAM-1⁺ cells in frontal cortex, striatum, and hippocampus were significantly increased following EE, suggesting the histological findings exhibit a similar pattern to the upregulation of FGF-2 in the brain. In conclusion, EE enhances endogenous angiogenesis and neurobehavioral functions mediated by upregulation of FGF-2 in chronic hypoxic-ischemic brain injury.</p></div

Synthesis and Properties of Two Cationic Narrow Band Gap Conjugated Polyelectrolytes

We report the design, synthesis, and optical and electronic properties of two novel narrow band gap conjugated polyelectrolytes (NBGCPEs) based on a poly­[2,6-(4,4-bis-alkyl-4<i>H</i>-cyclopenta­[2,1-<i>b</i>;3,4-<i>b</i>′]­dithio­phene)-<i>alt</i>-4,7-(2,1,3-benzothiadiazole)] donor/acceptor backbone. Comparison with the properties of the neutral precursor material shows that the ionic component in these cationic NBGCPEs leads to a red-shift in the absorption spectra and to a modification of the polymer electronic energy levels. Both the HOMO and the LUMO are lowered in energy, with the net effect being dependent on the choice of counterion, i.e. bromide vs tetrakis­(1-imid­azolyl)­borate. Moreover, we unexpectedly find n-type transport in thin-film transistors, as opposed to the widely studied p-type transport in neutral systems with isoelectronic backbones. From these observations we conclude that introduction of ionic functionalities adjacent to semiconducting polymers that exhibit charge-transfer excitations offers unique opportunities for materials design

Western blot analysis also confirmed activin A upregulation in the brain.

<p>(A–C) Analysis of activin A level in the striatum, cerebellum, and frontal cortex using western blotting. (A) Activin A was significantly upregulated in the striatum at 2 weeks after exposure to EE (^*<i>p</i><0.05, n = 3 each). (B) The activin A in the cerebellum is also highly expressed at 2 weeks after EE treatment (n = 3 each). (C) On the other hand, activin A significantly increased in the striatum at 8 weeks after exposure to EE (^*<i>p</i><0.05, n = each). HIE: hypoxic-ischemic encephalopathy, EE: enriched environment, SC: standard cages.</p

Environmental enrichment also enhanced endogenous angiogenesis in the hippocampus.

<p>(A, B) After exposure to EE, the capillary count and densities of PECAM-1⁺ cells were quantified using the MetaMorph Imaging System. Scale bar 150 μm. (A) Capillary count was increased in the dentate gyrus of the hippocampus at 8 weeks following the exposure to EE. (B) In particular, the densities of PECAM-1 in the EE mice were significantly higher than those in the SC controls at 8 weeks after treatment (^*<i>p</i><0.05, n = 5 each). HIE: hypoxic-ischemic encephalopathy, EE: enriched environment, SC: standard cages.</p

Environmental enrichment enhanced endogenous angiogenesis in the frontal cortex and striatum.

<p>(A–H, K–R) Two and 8 weeks after exposure to EE, the densities of α-SMA⁺ cells and PECAM-1⁺ cells were quantified using the MetaMorph Imaging System. Scale bar 50 μm. (I) The density of α-SMA⁺ cells was significantly higher in frontal cortex of EE mice than SC controls 8 weeks after treatment (^*<i>p</i><0.05, n = 5 each). (J) The HIE-EE mice also showed an increase in PECAM-1⁺ angiogenesis 2 weeks and 8 weeks after treatment (^*<i>p</i><0.05, n = 5 each). (S, T) The densities of α-SMA⁺ cells (S) and PECAM-1⁺ cells (T) were higher in the striatum of EE mice than SC controls at 2 weeks after treatment (^*<i>p</i><0.05, ^†<i>p</i><0.1, n = 5 each). (T) The densities of PECAM-1⁺ cells were also significantly increased at 8 weeks following the EE treatment (^*<i>p</i><0.05, n = 5 each). HIE: hypoxic-ischemic encephalopathy, EE: enriched environment, SC: standard cages.</p

Infusion of FGF-2 neutralizing antibody reversed functional recovery.

<p>(A, B) To confirm the relationship between EE-induced FGF-2 upregulation and behavioral benefits, subgroups of EE and SC mice with HI brain injury were randomly assigned to either SC/anti-FGF-2 (n = 3) or EE/anti-FGF-2 (n = 4). (A) All animals treated with anti-FGF-2 abolished the beneficial effect on motor performance relative to EE mice not given anti-FGF-2 at 8 weeks after treatment (^*<i>p</i><0.05). (B). Mice treated with EE/anti-FGF-2 also showed the decreased grip strength whereas grip strength of EE mice not given anti-FGF-2 was significantly increased compared to the other groups (^*<i>p</i><0.05).</p

Easily Attainable Phenothiazine-Based Polymers for Polymer Solar Cells: Advantage of Insertion of <i>S</i>,<i>S</i>-dioxides into its Polymer for Inverted Structure Solar Cells

Two donor– (D−) acceptor (A) type polymers based on a soluble chromophore of phenothiazine (PT) unit that is a tricyclic nitrogen–sulfur heterocycle, have been synthesized by introducing an electron-deficient benzothiadiazole (BT) building block copolymerized with either PT or phenothiazine-<i>S</i>,<i>S</i>-dioxide (PT-<i>SS</i>) unit as an oxidized form of PT. The resulting polymers, <b>PPTDTBT</b> and <b>PPTDTBT-</b><i><b>SS</b></i> are fully characterized by UV–vis absorption, electrochemical cyclic voltammetry, X-ray diffraction (XRD), and DFT theoretical calculations. We find that the maximum absorption of <b>PPTDTBT</b> is not only markedly red-shifted with respect to that of <b>PPTDTBT-</b><i><b>SS</b></i> but also its band gap as well as molecular energy levels are readily tuned by the insertion of <i>S</i>,<i>S</i>-dioxides into the polymer. The main interest is focused on the electronic applications of the two polymers in organic field-effect transistors (OFETs) as well as conventional and inverted polymeric solar cells (PSCs). <b>PPTDTBT</b> is a typical p-type polymer semiconductor for OFETs and conventional PSCs based on this polymer and PC₇₁BM show a power conversion efficiency (PCE) of 1.69%. In case of <b>PPTDTBT-</b><i><b>SS</b></i>, the devices characteristics result in: (i) 1 order of magnitude higher hole mobility (μ = 6.9 × 10^–4 cm² V^–1 s^–1) than that obtained with <b>PPTDTBT</b> and (ii) improved performance of the inverted PSCs (1.22%), compared to its conventional devices. Such positive features can be accounted for in terms of closer packing molecular characteristics owing either to the effects of dipolar intermolecular interactions orientated from the sulfonyl groups or the relatively high coplanarity of <b>PPTDTBT-</b><i><b>SS</b></i> backbone

Image_1_The Effect of Environmental Enrichment on Glutathione-Mediated Xenobiotic Metabolism and Antioxidation in Normal Adult Mice.pdf

<p>Olfactory bulb (OB) plays an important role in protecting against harmful substances via the secretion of antioxidant and detoxifying enzymes. Environmental enrichment (EE) is a common rehabilitation method and known to have beneficial effects in the central nervous system. However, the effects of EE in the OB still remain unclear. At 6 weeks of age, CD-1® (ICR) mice were assigned to standard cages or EE cages. After 2 months, we performed proteomic analysis. Forty-four up-regulated proteins were identified in EE mice compared to the control mice. Gene Ontology analysis and Kyoto Encyclopedia of Genes and Genomes Pathway demonstrated that the upregulated proteins were mainly involved in metabolic pathways against xenobiotics. Among those upregulated proteins, 9 proteins, which participate in phase I or II of the xenobiotic metabolizing process and are known to be responsible for ROS detoxification, were validated by qRT-PCR. To explore the effect of ROS detoxification mediated by EE, glutathione activity was measured by an ELISA assay. The ratio of reduced glutathione to oxidized glutathione was significantly increased in EE mice. Based on a linear regression analysis, GSTM2 and UGT2A1 were found to be the most influential genes in ROS detoxification. For further analysis of neuroprotection, the level of iNOS and the ratio of Bax to Bcl-2 were significantly decreased in EE mice. While TUNEL⁺ cells were significantly decreased, Ki67⁺ cells were significantly increased in EE mice, implicating that EE creates an optimal state for xenobiotic metabolism and antioxidant activity. Taken together, our results suggested that EE protects olfactory layers via the upregulation of glutathione-related antioxidant and xenobiotic metabolizing enzymes, eventually lowering ROS-mediated inflammation and apoptosis and increasing neurogenesis. This study may provide an opportunity for a better understanding of the beneficial effects of EE in the OB.</p