Signature of a silver phase percolation threshold in microscopically phase separated ternary Ge0.15Se0.85-xAgx (0 <= x <= 0.20) glasses

Temperature modulated Alternating Differential Scanning Calorimetric (ADSC) studies show that Se rich Ge0.15Se0.85-xAgx (0 <= x <= 0.20) glasses are microscopically phase separated, containing Ag2Se phases embedded in a Ge0.15Se0.85 backbone. With increasing silver concentration, Ag2Se phase percolates in the Ge-Se matrix, with a well-defined percolation threshold at x = 0.10. A signature of this percolation transition is shown up in the thermal behavior, as the appearance of two exothermic crystallization peaks. Density, molar volume and micro-hardness measurements, undertaken in the present study, also strongly support this view of percolation transition. The super-ionic conduction observed earlier in these glasses at higher silver proportions, is likely to be connected with the silver phase percolation.Comment: 4 pages, 7 figure

Effects of Growth Regulators and Explant-Type on Agrobacterium-Mediated Transformation in Brinjal (Solanum melongena L.) cv. Manjarigota

Effects of growth regulators and type of explants on transformation and in vitro morphogenetic responses of brinjal cv. Manjarigota were studied. Both hypocotyl and cotyledonary explants showed marked influence on in vitro morphogenetic responses after Agrobacterium co-cultivation. Hypocotyl explants showed callus initiation and regeneration responses earlier than cotyledonary leaves. Hypocotyl explants were found to be better than cotyledonary leaf explants in regenerating shoots after Agrobacterium co-cultivation. There was delay and reduction in both callus and regeneration responses in Agrobacterium co-cultivated explants. Hypocotyl explants showed the highest regeneration response on MS medium containing 2 μM BAP and 0.05 μM NAA while cotyledonary leaves did not show regeneration response after Agrobacterium co-cultivation. However, they showed green buds on MS medium containing 10 μM BAP and 1 μM NAA, which could not differentiate into shoots. Overall, hypocotyl explants were found better in regenerating shoots after Agrobacterium co-cultivation

Effect of Antibiotics and Gelling Agents in Transformation of Brinjal (Solanum melongena L.) cv. Manjarigota

A study was conducted to find out the effect of antibiotics and gelling agents on Agrobacterium-mediated transformation using hypocotyl explants of brinjal cv. Manjarigota. Hypocotyl explants of brinjal were found to be sensitive even to the lowest level of kanamycin (25 mg/l) tested. Explants that showed increased callus initiation and regeneration response upon cocultivation with Agrobacterium and on kanamycin at 100 mg/l were selected as this indicated a highly effective selection pressure. Cefotaxime did not affect regeneration response and at 500 mg/l, it effectively inhibited Agrobacterium overgrowth completely on Agrobacterium cocultivated hypocotyl explants. There were marked differences in regeneration response in hypocotyl explants cultured on medium solidified with various gelling agents indicating the influence of gelling agent on the activity of kanamycin in culture medium, which indirectly affects selection and recovery of transformants. Antibiotics and gelling agents could therefore affect, directly or indirectly, transformation of brinjal cv. Manjarigota

Synergistic Use of Hypocotyl Explants and High Bap Preconditioning for Enhanced Transformation Frequency in Brinjal (Solanum melongena L.)

Poor regeneration is one of the limiting factors in the development of transgenic crops since Agrobacterium as a plant pathogen can disturb the fragile in vitro conditions with wounding and infection regimes. We have tried to optimize the transformation system in two important varieties of brinjal after Agrobacterium infection to the explants. The effect of explant was studied and hypocotyls were found to be better than cotyledonary leaves. High BAP during the preconditioning period was found to further enhance the regeneration rate. Therefore, use of hypocotyls and high BAP during preconditioning can improve the regeneration of transformed cells and recovery of transformants in vegetables especially brinjal

Electrochemical testing of carbon materials as bromine electrodes for the hydrogen-bromine redox flow battery

This is the final version. Available on open access from MDPI via the DOI in this recordHydrogen-bromine (H2-Br2) redox flow batteries (RFBs) have gained a lot of interest due to their advantages in mitigating the performance shortcomings of conventional zinc-bromine and vanadium flow batteries. Various carbon materials have been tested in H2-Br2 RFBs as bromine electrodes. However, a comparative study between different carbon materials has not been reported in literature. This work reports for the first time an evaluation of carbon papers, felt and cloth in a three-electrode half-cell setup as potential bromine electrodes, in pristine and thermally treated state. A systematic evaluation was performed by comparing the surface morphologies, kinetic parameters, polarisation curves and stability tests of different carbon electrodes. Thermally treated graphite felt electrode demonstrated the best electrochemical performance as bromine electrode owing to its improved surface area, hydrophilicity and intrinsic activity. Further in-depth studies will shed important insights which will help understand the electrode characteristics for future bromine battery design. The current study will assist in evaluating the performance of upcoming novel electrode materials in three electrode assembly.European Union Horizon 2020Engineering and Physical Sciences Research Council (EPSRC)Royal Academy of Engineering (RAE

An siRNA Screen Identifies the U2 snRNP Spliceosome as a Host Restriction Factor for Recombinant Adeno-associated Viruses

Adeno-associated viruses (AAV) have evolved to exploit the dynamic reorganization of host cell machinery during co-infection by adenoviruses and other helper viruses. In the absence of helper viruses, host factors such as the proteasome and DNA damage response machinery have been shown to effectively inhibit AAV transduction by restricting processes ranging from nuclear entry to second-strand DNA synthesis. To identify host factors that might affect other key steps in AAV infection, we screened an siRNA library that revealed several candidate genes including the PHD finger-like domain protein 5A (PHF5A), a U2 snRNP-associated protein. Disruption of PHF5A expression selectively enhanced transgene expression from AAV by increasing transcript levels and appears to influence a step after second-strand synthesis in a serotype and cell type-independent manner. Genetic disruption of U2 snRNP and associated proteins, such as SF3B1 and U2AF1, also increased expression from AAV vector, suggesting the critical role of U2 snRNP spliceosome complex in this host-mediated restriction. Notably, adenoviral co-infection and U2 snRNP inhibition appeared to target a common pathway in increasing expression from AAV vectors. Moreover, pharmacological inhibition of U2 snRNP by meayamycin B, a potent SF3B1 inhibitor, substantially enhanced AAV vector transduction of clinically relevant cell types. Further analysis suggested that U2 snRNP proteins suppress AAV vector transgene expression through direct recognition of intact AAV capsids. In summary, we identify U2 snRNP and associated splicing factors, which are known to be affected during adenoviral infection, as novel host restriction factors that effectively limit AAV transgene expression. Concurrently, we postulate that pharmacological/genetic manipulation of components of the spliceosomal machinery might enable more effective gene transfer modalities with recombinant AAV vectors

Detecting Distributed Denial of Service Attacks in Neighbour Discovery Protocol Using Machine Learning Algorithm Based on Streams Representation

© 2018, Springer International Publishing AG, part of Springer Nature. The main protocol of the Internet protocol version 6 suites is the neighbour discovery protocol, which is geared towards substitution of address resolution protocol, router discovery, and function redirection in Internet protocol version 4. Internet protocol version 6 nodes employ neighbour discovery protocol to detect linked hosts and routers in Internet protocol version 6 network without the dependence on dynamic host configuration protocol server, which has earned the neighbour discovery protocol the title of the stateless protocol. The authentication process of the neighbour discovery protocol exhibits weaknesses that make this protocol vulnerable to attacks. Denial of service attacks can be triggered by a malicious host through the introduction of spoofed addresses in neighbour discovery protocol messages. Internet version 6 protocols are not well supported by Network Intrusion Detection System as is the case with Internet Protocol version 4 protocols. Several data mining techniques have been introduced to improve the classification mechanism of Intrusion detection system. In addition, extensive researches indicated that there is no Intrusion Detection system for Internet Protocol version 6 using advanced machine-learning techniques toward distributed denial of service attacks. This paper aims to detect Distributed Denial of Service attacks of the Neighbour Discovery protocol using machine-learning techniques, due to the severity of the attacks and the importance of Neighbour Discovery protocol in Internet Protocol version 6. Decision tree algorithm and Random Forest Algorithm showed high accuracy results in comparison to the other benchmarked algorithms

Rings and rigidity transitions in network glasses

Three elastic phases of covalent networks, (I) floppy, (II) isostatically rigid and (III) stressed-rigid have now been identified in glasses at specific degrees of cross-linking (or chemical composition) both in theory and experiments. Here we use size-increasing cluster combinatorics and constraint counting algorithms to study analytically possible consequences of self-organization. In the presence of small rings that can be locally I, II or III, we obtain two transitions instead of the previously reported single percolative transition at the mean coordination number $\bar r=2.4$, one from a floppy to an isostatic rigid phase, and a second one from an isostatic to a stressed rigid phase. The width of the intermediate phase $~ \bar r$ and the order of the phase transitions depend on the nature of medium range order (relative ring fractions). We compare the results to the Group IV chalcogenides, such as Ge-Se and Si-Se, for which evidence of an intermediate phase has been obtained, and for which estimates of ring fractions can be made from structures of high T crystalline phases.Comment: 29 pages, revtex, 7 eps figure

Efficient Performance of Electrostatic Spray-Deposited TiO2 Blocking Layers in Dye-Sensitized Solar Cells after Swift Heavy Ion Beam Irradiation

A compact TiO2 layer (~1.1 μm) prepared by electrostatic spray deposition (ESD) and swift heavy ion beam (SHI) irradiation using oxygen ions onto a fluorinated tin oxide (FTO) conducting substrate showed enhancement of photovoltaic performance in dye-sensitized solar cells (DSSCs). The short circuit current density (Jsc = 12.2 mA cm-2) of DSSCs was found to increase significantly when an ESD technique was applied for fabrication of the TiO2 blocking layer, compared to a conventional spin-coated layer (Jsc = 8.9 mA cm-2). When SHI irradiation of oxygen ions of fluence 1 × 1013 ions/cm2 was carried out on the ESD TiO2, it was found that the energy conversion efficiency improved mainly due to the increase in open circuit voltage of DSSCs. This increased energy conversion efficiency seems to be associated with improved electronic energy transfer by increasing the densification of the blocking layer and improving the adhesion between the blocking layer and the FTO substrate. The adhesion results from instantaneous local melting of the TiO2 particles. An increase in the electron transport from the blocking layer may also retard the electron recombination process due to the oxidized species present in the electrolyte. These findings from novel treatments using ESD and SHI irradiation techniques may provide a new tool to improve the photovoltaic performance of DSSCs

Functional Analysis of the Putative Integrin Recognition Motif on Adeno-associated Virus 9

Adeno-associated viruses (AAVs) display a highly conserved NGR motif on the capsid surface. Earlier studies have established this tripeptide motif as being essential for integrin-mediated uptake of recombinant AAV serotype 2 (AAV2) in cultured cells. However, functional attributes of this putative integrin recognition motif in other recombinant AAV serotypes displaying systemic transduction in vivo remain unknown. In this study, we dissect the biology of an integrin domain capsid mutant derived from the human isolate AAV9 in mice. The AAV9/NGA mutant shows decreased systemic transduction in mice. This defective phenotype was accompanied by rapid clearance of mutant virions from the blood circulation and nonspecific sequestration by the spleen. Transient vascular hyperpermeability, induced by histamine coinjection, exacerbated AAV9/NGA uptake by the spleen but not the liver. However, such treatment did not affect AAV9 virions, suggesting a potential entry/post-entry defect for the mutant in different tissues. Further characterization revealed modestly decreased cell surface binding but a more pronounced defect in the cellular entry of mutant virions. These findings were corroborated by the observation that blocking multiple integrins adversely affected recombinant AAV9 transduction in different cell types, albeit with variable efficiencies. From a structural perspective, we observed that the integrin recognition motif is located in close proximity to the galactose binding footprint on AAV9 capsids and postulate that this feature could influence cell surface attachment, cellular uptake at the tissue level, and systemic clearance by the reticuloendothelial system