Hole-transporting spirothioxanthene derivatives as donor materials for efficient small-molecule-based organic photovoltaic devices

Poster: no. 30Taking the advantages of the 3D structure and rigid spiro-conjugation, spirobifluorene and its derivatives are a benchmark class of p-type semiconductors in organic electronic devices because of their good charge-transporting properties. However, their low absorption coefficients within the visible spectrum render their application as photoactive materials in the fabrication of organic photovoltaic (OPV) devices. A new class of heterocyclic spirothioxanthene derivatives has been designed and synthesized by the functionalization of the spiro core with various triarylamine groups and the modification of the heteroatom of the spiro core. The photophysical, electrochemical and thermal properties of these spirothioxanthene derivatives have been fully characterized. Of particular interest, all of these compounds exhibit high hole mobilities of up to 10–3 cm2V–1s–1, as determined from thin film transistor measurement. More importantly, these spirothioxanthene derivatives are promising donor materials for the fabrication of high performance OPV devices. With a very low dopant concentration of 7 % doped into fullerene matrix, efficient small molecular-based OPV devices with high open-circuit voltage of 0.94 V and high power conversion efficiency of 5.40 % (the highest PCE of 5.46 %) have been realized. This demonstrates for the first time their application studies as photovoltaic donor materials in OPV devices.published_or_final_versio

Mycotoxin Zearalenone induced apoptosis in BEAS-2B cells through generation of ROS and activation of JNK and p38 MAPKs signalling pathways

Session: ET05P - Ecotoxicology and ecosystem services: A southern perspective: WE 304Human exposure to Zearalenone (ZEA, a non-steroidal estrogenic mycotoxin) through inhalation has raised considerable concern. However, the potential health risk and the mechanism of actions of ZEA are not well understood. In the present study, we used BEAS-2B, cultured human bronchial epithelial cells, as well as Cygb stably transfected BEAS-2B cells to study the cytotoxic effects and the toxic mechanisms of ZEA. Our results indicated that ZEA decreased cell viability, induced apoptosis and promoted ROS level in BEAS-2B cells. Oxidative stress was clearly evident, as shown by an elevated mRNA expression levels of oxidative stress markers (Hsp70 and Hsp27) and endogenous antioxidants (SOD2 and Gpx). Stable transfection of Cygb significantly increased the level of Cygb but reduced level of ROS and the percentage of apoptotic cells induced by ZEA. Cells pretreated with either p38 or JNK inhibitors showed no attenuation in ROS level, but the percentage of apoptotic cells was lower than cells treated with ZEApostprin

Jejunal Variceal Bleeding Successfully Treated with Percutaneous Coil Embolization

A 52-yr-old male with alcoholic liver cirrhosis was hospitalized for hematochezia. He had undergone small-bowel resection due to trauma 15 yr previously. Esophagogastroduodenoscopy showed grade 1 esophageal varices without bleeding. No bleeding lesion was seen on colonoscopy, but capsule endoscopy showed suspicious bleeding from angiodysplasia in the small bowel. After 2 weeks of conservative treatment, the hematochezia stopped. However, 1 week later, the patient was re-admitted with hematochezia and a hemoglobin level of 5.5 g/dL. Capsule endoscopy was performed again and showed active bleeding in the mid-jejunum. Abdominal computed tomography revealed a varix in the jejunal branch of the superior mesenteric vein. A direct portogram performed via the transhepatic route showed portosystemic collaterals at the distal jejunum. The patient underwent coil embolization of the superior mesenteric vein just above the portosystemic collaterals and was subsequently discharged without re-bleeding. At 8 months after discharge, his condition has remained stable, without further bleeding episodes

Magnetism and its microscopic origin in iron-based high-temperature superconductors

High-temperature superconductivity in the iron-based materials emerges from, or sometimes coexists with, their metallic or insulating parent compound states. This is surprising since these undoped states display dramatically different antiferromagnetic (AF) spin arrangements and N$\rm \acute{e}$el temperatures. Although there is general consensus that magnetic interactions are important for superconductivity, much is still unknown concerning the microscopic origin of the magnetic states. In this review, progress in this area is summarized, focusing on recent experimental and theoretical results and discussing their microscopic implications. It is concluded that the parent compounds are in a state that is more complex than implied by a simple Fermi surface nesting scenario, and a dual description including both itinerant and localized degrees of freedom is needed to properly describe these fascinating materials.Comment: 14 pages, 4 figures, Review article, accepted for publication in Nature Physic

Evolutionary and pulsational properties of white dwarf stars

Abridged. White dwarf stars are the final evolutionary stage of the vast majority of stars, including our Sun. The study of white dwarfs has potential applications to different fields of astrophysics. In particular, they can be used as independent reliable cosmic clocks, and can also provide valuable information about the fundamental parameters of a wide variety of stellar populations, like our Galaxy and open and globular clusters. In addition, the high densities and temperatures characterizing white dwarfs allow to use these stars as cosmic laboratories for studying physical processes under extreme conditions that cannot be achieved in terrestrial laboratories. They can be used to constrain fundamental properties of elementary particles such as axions and neutrinos, and to study problems related to the variation of fundamental constants. In this work, we review the essentials of the physics of white dwarf stars. Special emphasis is placed on the physical processes that lead to the formation of white dwarfs as well as on the different energy sources and processes responsible for chemical abundance changes that occur along their evolution. Moreover, in the course of their lives, white dwarfs cross different pulsational instability strips. The existence of these instability strips provides astronomers with an unique opportunity to peer into their internal structure that would otherwise remain hidden from observers. We will show that this allows to measure with unprecedented precision the stellar masses and to infer their envelope thicknesses, to probe the core chemical stratification, and to detect rotation rates and magnetic fields. Consequently, in this work, we also review the pulsational properties of white dwarfs and the most recent applications of white dwarf asteroseismology.Comment: 85 pages, 28 figures. To be published in The Astronomy and Astrophysics Revie

Predictors of anti-convulsant treatment failure in children presenting with malaria and prolonged seizures in Kampala, Uganda

BACKGROUND: In endemic areas, falciparum malaria remains the leading cause of seizures in children presenting to emergency departments. In addition, seizures in malaria have been shown to increase morbidity and mortality in these patients. The management of seizures in malaria is sometimes complicated by the refractory nature of these seizures to readily available anti-convulsants. The objective of this study was to determine predictors of anti-convulsant treatment failure and seizure recurrence after initial control among children with malaria. METHODS: In a previous study, the efficacy and safety of buccal midazolam was compared to that of rectal diazepam in the treatment of prolonged seizures in children aged three months to 12 years in Kampala, Uganda. For this study, predictive models were used to determine risk factors for anti-convulsant treatment failure and seizure recurrence among the 221 of these children with malaria. RESULTS: Using predictive models, focal seizures (OR 3.21; 95% CI 1.42-7.25, p = 0.005), cerebral malaria (OR 2.43; 95% CI 1.20-4.91, p = 0.01) and a blood sugar >or=200 mg/dl at presentation (OR 2.84; 95% CI 1.11-7.20, p = 0.02) were independent predictors of treatment failure (seizure persistence beyond 10 minutes or recurrence within one hour of treatment). Predictors of seizure recurrence included: 1) cerebral malaria (HR 3.32; 95% CI 1.94-5.66, p < 0.001), 2) presenting with multiple seizures (HR 2.45; 95% CI 1.42-4.23, p = 0.001), 3) focal seizures (HR 2.86; 95% CI 1.49-5.49, p = 0.002), 4) recent use of diazepam (HR 2.43; 95% CI 1.19-4.95, p = 0.01) and 5) initial control of the seizure with diazepam (HR 1.96; 95% CI 1.16-3.33, p = 0.01). CONCLUSION: Specific predictors, including cerebral malaria, can identify patients with malaria at risk of anti-convulsant treatment failure and seizure recurrence

Structure and function of the Ts2631 endolysin of <i>Thermus scotoductus</i> phage vB_Tsc2631 with unique N-terminal extension used for peptidoglycan binding

Abstract To escape from hosts after completing their life cycle, bacteriophages often use endolysins, which degrade bacterial peptidoglycan. While mesophilic phages have been extensively studied, their thermophilic counterparts are not well characterized. Here, we present a detailed analysis of the structure and function of Ts2631 endolysin from thermophilic phage vB_Tsc2631, which is a zinc-dependent amidase. The active site of Ts2631 consists of His30, Tyr58, His131 and Cys139, which are involved in Zn2+ coordination and catalysis. We found that the active site residues are necessary for lysis yet not crucial for peptidoglycan binding. To elucidate residues involved in the enzyme interaction with peptidoglycan, we tested single-residue substitution variants and identified Tyr60 and Lys70 as essential residues. Moreover, substitution of Cys80, abrogating disulfide bridge formation, inactivates Ts2631, as do substitutions of His31, Thr32 and Asn85 residues. The endolysin contains a positively charged N-terminal extension of 20 residues that can protrude from the remainder of the enzyme and is crucial for peptidoglycan binding. We show that the deletion of 20 residues from the N-terminus abolished the bacteriolytic activity of the enzyme. Because Ts2631 exhibits intrinsic antibacterial activity and unusual thermal stability, it is perfectly suited as a scaffold for the development of antimicrobial agents

Measurement of the inclusive and dijet cross-sections of b-jets in pp collisions at sqrt(s) = 7 TeV with the ATLAS detector

The inclusive and dijet production cross-sections have been measured for jets containing b-hadrons (b-jets) in proton-proton collisions at a centre-of-mass energy of sqrt(s) = 7 TeV, using the ATLAS detector at the LHC. The measurements use data corresponding to an integrated luminosity of 34 pb^-1. The b-jets are identified using either a lifetime-based method, where secondary decay vertices of b-hadrons in jets are reconstructed using information from the tracking detectors, or a muon-based method where the presence of a muon is used to identify semileptonic decays of b-hadrons inside jets. The inclusive b-jet cross-section is measured as a function of transverse momentum in the range 20 < pT < 400 GeV and rapidity in the range |y| < 2.1. The bbbar-dijet cross-section is measured as a function of the dijet invariant mass in the range 110 < m_jj < 760 GeV, the azimuthal angle difference between the two jets and the angular variable chi in two dijet mass regions. The results are compared with next-to-leading-order QCD predictions. Good agreement is observed between the measured cross-sections and the predictions obtained using POWHEG + Pythia. MC@NLO + Herwig shows good agreement with the measured bbbar-dijet cross-section. However, it does not reproduce the measured inclusive cross-section well, particularly for central b-jets with large transverse momenta.Comment: 10 pages plus author list (21 pages total), 8 figures, 1 table, final version published in European Physical Journal