Perylene diimides functionalized with N-thiadiazole substituents: Synthesis and electronic properties in OFET devices

Two new perylene diimide derivatives N,N′-bis(5-tridecyl-1,3,4- thiadiazol-2-yl)perylene-3,4,9,10-tetracarboxylic 3,4:9,10-diimide (PDI-T1) and N,N′-bis[5-(1-hexyl)nonyl-1,3,4-thiadiazol-2-yl]perylene-3,4,9, 10-tetracarboxylic 3,4:9,10-diimide (PDI-T2), achieved by functionalizing the basic perylene molecular core at imide nitrogen with 1,3,4-thiadiazole rings, have been synthesized. Both these compounds make possible the fabrication of n-type organic thin-film transistors able to work in air, even when bare SiO2 surfaces are utilized as gate dielectric. As active channels of transistors in the bottom-contact bottom-gate configuration, PDI-T1 evaporated films exhibited a maximum mobility of 0.016 cm2/V s in vacuum. For evaporated PDI-T2 films, instead, mobility values were found to be more than one order of magnitude lower, because of their reduced degree of crystalline order. However, PDI-T2 films can be also deposited by solution techniques and field-effect transistors were fabricated by spin-coating, displaying mobility values ranging between 10-6 and 10-5 cm2/V s. Similar to what previously found for other perylene diimide derivatives, our experimental work also demonstrates that the electrical response of both PDI-T1 and PDI-T2 transistors under ambient conditions can be improved by increasing the level of hydrophobicity of the dielectric surface. © 2012 Elsevier B.V. All rights reserved

A natural Finsler--Laplace operator

We give a new definition of a Laplace operator for Finsler metric as an average with regard to an angle measure of the second directional derivatives. This definition uses a dynamical approach due to Foulon that does not require the use of connections nor local coordinates. We show using 1-parameter families of Katok--Ziller metrics that this Finsler--Laplace operator admits explicit representations and computations of spectral data.Comment: 25 pages, v2: minor modifications, changed the introductio

Synthesis of highly regioregular poly[3-(4-alkoxyphenyl)-thiophene]s by oxidative catalysis using copper complexes

A novel, easy, and cost-effective synthetic procedure is reported for the production of very highly regioregular poly[3-(4-alkoxyphenyl)thiophene]s by means of oxidative coupling. Four copper complexes were synthesized and used as catalysts to obtain polymers with higher regioregularity compared to the previous oxidative coupling methodologies reported in the literature and similar to that obtained by McCullough and Rieke methods in the synthesis of poly-3-alkylthiophenes. The regioregularity of the synthesized polymers was investigated by UV-Visible characterization on polymer thin films and 1H NMR analysis. The remarkable potentialities of these polymers have emerged from field-effect transistor mobility measurements operated on devices with bottom-contact configuration and hexamethyldisilazane-treated SiO 2 gate dielectric, showing a well-defined p-type field-effect response and maximum mobility values in air higher than 10-4 cm 2 V-1 s-1. © 2013 Wiley Periodicals, Inc

Novel USH1G homozygous variant underlying USH2-like phenotype of Usher syndrome

PURPOSE: Usher syndrome (USH) is an autosomal recessive disorder characterized by congenital sensorineural hearing impairment and retinitis pigmentosa. Classification distinguishes three clinical types of which type I (USH1) is the most severe, with vestibular dysfunction as an added feature. To date, 15 genes and 3 loci have been identified with the USH1G gene being an uncommon cause of USH. We describe an atypical USH1G-related phenotype caused by a novel homozygous missense variation in a patient with profound hearing impairment and relatively mild retinitis pigmentosa, but no vestibular dysfunction. METHODS: A 26-year-old female patient with profound congenital sensorineural hearing loss, nyctalopia and retinitis pigmentosa was studied. Audiometric, vestibular and ophthalmologic examination was performed. A panel of 13 genes was tested by next-generation sequencing (NGS). RESULTS: While the hearing loss was confirmed to be profound, the vestibular function resulted normal. Although typical retinitis pigmentosa was present, the age at onset was unusually late for USH1 syndrome. A novel homozygous missense variation (c.1187T>A, p.Leu396Gln) in the USH1G gene has been identified as causing the disease in our patient. CONCLUSIONS: Genetic and phenotypic heterogeneity are very common in both isolated and syndromic retinal dystrophies and sensorineural hearing loss. Our findings widen the spectrum of USH allelic disorders and strength the concept that variants in genes that are classically known as underlying one specific clinical USH subtype might result in unexpected phenotypes

The conserved C-terminus of the PcrA/UvrD helicase interacts directly with RNA polymerase

Copyright: © 2013 Gwynn et al. This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Funding: This work was supported by a Wellcome Trust project grant to MD (Reference: 077368), an ERC starting grant to MD (Acronym: SM-DNA-REPAIR) and a BBSRC project grant to PM, NS and MD (Reference: BB/I003142/1). The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.Peer reviewedPublisher PD

Differential Requirements of Two recA Mutants for Constitutive SOS Expression in Escherichia coli K-12

Background Repairing DNA damage begins with its detection and is often followed by elicitation of a cellular response. In E. coli, RecA polymerizes on ssDNA produced after DNA damage and induces the SOS Response. The RecA-DNA filament is an allosteric effector of LexA auto-proteolysis. LexA is the repressor of the SOS Response. Not all RecA-DNA filaments, however, lead to an SOS Response. Certain recA mutants express the SOS Response (recAC) in the absence of external DNA damage in log phase cells. Methodology/Principal Findings Genetic analysis of two recAC mutants was used to determine the mechanism of constitutive SOS (SOSC) expression in a population of log phase cells using fluorescence of single cells carrying an SOS reporter system (sulAp-gfp). SOSC expression in recA4142 mutants was dependent on its initial level of transcription, recBCD, recFOR, recX, dinI, xthA and the type of medium in which the cells were grown. SOSC expression in recA730 mutants was affected by none of the mutations or conditions tested above. Conclusions/Significance It is concluded that not all recAC alleles cause SOSC expression by the same mechanism. It is hypothesized that RecA4142 is loaded on to a double-strand end of DNA and that the RecA filament is stabilized by the presence of DinI and destabilized by RecX. RecFOR regulate the activity of RecX to destabilize the RecA filament. RecA730 causes SOSC expression by binding to ssDNA in a mechanism yet to be determined

Bromodomain inhibition of the transcriptional coactivators CBP/EP300 as a therapeutic strategy to target the IRF4 network in multiple myeloma

Abstract Pharmacological inhibition of chromatin co-regulatory factors represents a clinically validated strategy to modulate oncogenic signaling through selective attenuation of gene expression. Here, we demonstrate that CBP/EP300 bromodomain inhibition preferentially abrogates the viability of multiple myeloma cell lines. Selective targeting of multiple myeloma cell lines through CBP/EP300 bromodomain inhibition is the result of direct transcriptional suppression of the lymphocyte-specific transcription factor IRF4, which is essential for the viability of myeloma cells, and the concomitant repression of the IRF4 target gene c-MYC. Ectopic expression of either IRF4 or MYC antagonizes the phenotypic and transcriptional effects of CBP/EP300 bromodomain inhibition, highlighting the IRF4/MYC axis as a key component of its mechanism of action. These findings suggest that CBP/EP300 bromodomain inhibition represents a viable therapeutic strategy for targeting multiple myeloma and other lymphoid malignancies dependent on the IRF4 network

Valorisation of agricultural biomass‑ash with CO2

This work is part of a study of different types of plant-based biomass to elucidate their capacity for valorisation via a managed carbonation step involving gaseous carbon dioxide (co2). the perspectives for broader biomass waste valorisation was reviewed, followed by a proposed closed‑loop process for the valorisation of wood in earlier works. the present work newly focusses on combining agricultural biomass with mineralised co2. Here, the reactivity of selected agricultural biomass ashes with co2 and their ability to be bound by mineralised carbonate in a hardened product is examined. three categories of agricultural biomass residues, including shell, fibre and soft peel, were incinerated at 900 ± 25 °C. The biomass ashes were moistened (10% w/w) and moulded into cylindrical samples and exposed to 100% CO2 gas at 50% RH for 24 h, during which they cemented into hardened monolithic products. the calcia in ashes formed a negative relationship with ash yield and the microstructure of the carbonate‑cementing phase was distinct and related to the particular biomass feedstock. this work shows that in common with woody biomass residues, carbonated agricultural biomass ash‑based monoliths have potential as novel low‑carbon construction products