The Self-Association of Graphane Is Driven by London Dispersion and Enhanced Orbital Interactions

We investigated the nature of the cohesive energy between graphane sheets via multiple CH center dot center dot center dot HC interactions, using density functional theory (DFT) including dispersion correction (Grimmes D3 approach) computations of n]graphane sigma dimers (n = 6-73). For comparison, we also evaluated the binding between graphene sheets that display prototypical pi/pi interactions. The results were analyzed using the block-localized wave function (BLW) method, which is a variant of ab initio valence bond (VB) theory. BLW interprets the intermolecular interactions in terms of frozen interaction energy (Delta E-F) composed of electrostatic and Pauli repulsion interactions, polarization (Delta E-pol), charge-transfer interaction (Delta E-CT), and dispersion effects (Delta E-disp). The BLW analysis reveals that the cohesive energy between graphane sheets is dominated by two stabilizing effects, namely intermolecular London dispersion and two-way charge transfer energy due to the sigma CH -> sigma*(HC) interactions. The shift of the electron density around the nonpolar covalent C-H bonds involved in the intermolecular interaction decreases the C-H bond lengths uniformly by 0.001 angstrom. The Delta E-CT term, which accounts for similar to 15% of the total binding energy, results in the accumulation of electron density in the interface area between two layers. This accumulated electron density thus acts as an electronic glue for the graphane layers and constitutes an important driving force in the self-association and stability of graphane under ambient conditions. Similarly, the double faced adhesive tape style of charge transfer interactions was also observed among graphene sheets in which it accounts for similar to 18% of the total binding energy. The binding energy between graphane sheets is additive and can be expressed as a sum of CH center dot center dot center dot HC interactions, or as a function of the number of C-H bonds.

Creating a specialist protein resource network: a meeting report for the protein bioinformatics and community resources retreat

During 11-12 August 2014, a Protein Bioinformatics and Community Resources Retreat was held at the Wellcome Trust Genome Campus in Hinxton, UK. This meeting brought together the principal investigators of several specialized protein resources (such as CAZy, TCDB and MEROPS) as well as those from protein databases from the large Bioinformatics centres (including UniProt and RefSeq). The retreat was divided into five sessions: (1) key challenges, (2) the databases represented, (3) best practices for maintenance and curation, (4) information flow to and from large data centers and (5) communication and funding. An important outcome of this meeting was the creation of a Specialist Protein Resource Network that we believe will improve coordination of the activities of its member resources. We invite further protein database resources to join the network and continue the dialogue.

Precision estimates and suggested sample sizes for length-frequency data

For most fisheries applications, the shape of a length-frequency distribution is much more important than its mean length or variance. This makes it difficult to evaluate at which point a sample size is adequate. By estimating the coefficient of variation of the counts in each length class and taking a weighted mean of these, a measure of precision was obtained that takes the precision in all length classes into account. The precision estimates were closely associated with the ratio of the sample size to the number of size classes in each sample. As a rule-of-thumb, a minimum sample size of 10 times the number of length classes in the sample is suggested because the precision deteriorates rapidly for smaller sample sizes. In absence of such a rule-of-thumb, samplers have previously under-estimated the required sample size for samples with large fish, while over-sampling small fish of the same species.

High current density nanofilament cathodes for microwave amplifiers

The fabrication of high current density nanofilament cathodes for microwave amplifiers was discussed. Metallic nanowires grown on silicon wafers and carbon nanotubes/nanofibers grown by catalytic plasma enhanced chemical vapor deposition (PECVD) were the two types of nanofilament arrays analyzed as cathodes materials. It was observed that the arrays of 5.8 μm height and 50 nm diameter carbon nanotubes exhibited geometrical enhancement factor of 240+-7.5%. The results show that carbon nanotubes/nanofibers arrays are best suited for nanofilament cathodes.

On the troll line investigations off Cochin during five fishing seasons. Pt. 1. Investigations during 1960-61 and 1961-62 seasons

There is apparently great scope for improvement of the design and operational aspects of the gear particularly for the effective exploitation of seasonal fisheries like that of seer, tuna, barracuda etc. In order to evolve improved, yet cheap trolling gear regular investigations were undertaken by the Craft & Gear Wing of the Central Institute of Fisheries Technology, off Cochin for five fishing seasons and the results of these studies are incorporated in this paper.

Characterizing a monotopic membrane enzyme. Biochemical, enzymatic and crystallization studies on Aquifex aeolicus sulfide:quinone oxidoreductase

Monotopic membrane proteins are membrane proteins that interact with only one leaflet of the lipid bilayer and do not possess transmembrane spanning segments. They are endowed with important physiological functions but until now only few of them have been studied. Here we present a detailed biochemical, enzymatic and crystallographic characterization of the monotopic membrane protein sulfide:quinone oxidoreductase. Sulfide:quinone oxidoreductase is a ubiquitous enzyme involved in sulfide detoxification, in sulfide-dependent respiration and photosynthesis, and in heavy metal tolerance. It may also play a crucial role in mammals, including humans, because sulfide acts as a neurotransmitter in these organisms. We isolated and purified sulfide:quinone oxidoreductase from the native membranes of the hyperthermophilic bacterium Aquifex aeolicus. We studied the pure and solubilized enzyme by denaturing and non-denaturing polyacrylamide electrophoresis, size-exclusion chromatography, cross-linking, analytical ultracentrifugation, visible and ultraviolet spectroscopy, mass spectrometry and electron microscopy. Additionally, we report the characterization of its enzymatic activity before and after crystallization. Finally, we discuss the crystallization of sulfide:quinone oxidoreductase in respect to its membrane topology and we propose a classification of monotopic membrane protein crystal lattices. Our data support and complement an earlier description of the three-dimensional structure of A. aeolicus sulfide:quinone oxidoreductase (M. Marcia, U. Ermler, G. Peng, H. Michel, Proc Natl Acad Sci USA, 106 (2009) 9625-9630) and may serve as a reference for further studies on monotopic membrane proteins. (C) 2010 Elsevier B.V. All rights reserved.

Wavelength division multiplexing at 2μm

This paper shows, for the first time, the implementation of a WDM subsystem at the 2μm wavelength window with mixed formats. Three wavelength channels were directly modulated withBPSK Fast-OFDM at 5Gbit/s per channel, with a fourth channel NRZ-OOK externally modulated at8.5Gbit/s giving a total capacity in excess of 20 Gbit/s.

Systemic recruitment of osteoblastic cells in fracture healing

We hypothesise that following a bone fracture there is systemic recruitment of bone forming cells to a fracture site. A rabbit ulnar osteotomy model was adapted to trace the movement of osteogenic cells. Bone marrow mesenchymal stem cells from 41 NZW rabbits were isolated, culture-expanded and fluorescently labelled. The labelled cells were either re-implanted into the fracture gap (Group A); into a vein (Group B); or into a remote tibial bone marrow cavity 48 h after the osteotomy (Group C) or 4 weeks before the osteotomy was established (Group D), and a control group (Group E) had no labelled cells given. To quantify passive leakage of cells to an injury site, inert beads were also co-delivered in Group B. Samples of the fracture callus tissue and various organs were harvested at discrete sacrifice time-points to trace and quantify the labelled cells. At 3 weeks following osteotomy, the number of labelled cells identified in the callus of Group C, was significantly greater than following IV delivery, Group B, and there was no difference in the number of labelled cells in the callus tissues, between Groups C and A, indicating the labelled bone marrow cells were capable of migrating to the fracture sites from the remote bone marrow cavity. Significantly fewer inert beads than labelled cells were identified in Group B callus, suggesting some of the bone-forming cells were actively recruited and selectively chosen to the fracture site, rather than passively leaked into the circulation and to bone injury site. This investigation supports the hypothesis that some osteoblasts involved in fracture healing were systemically mobilised and recruited to the fracture from remote bone marrow sites. © 2005 Orthopaedic Research Society. Published by Elsevier Ltd. All rights reserved.

Effects of plastic coating on K-alpha yield from ultra-short pulse

A study of the K-alpha radiation emitted from Ti foils irradiated with intense, similar to0.2 J, 67 fs, 800 nm laser pulses, scanning a range of intensities (similar to10(15)-10(18) W cm(-2)), is reported. The brightness of single-shot K-alpha line emission from the front of the targets is recorded. The yield from bare titanium (Ti) is compared to that from plastic (parylene-E) coated Ti. It is demonstrated that, for a defocused beam, a thin layer of plastic increases the yield.

On the road from consultation cynicism to energising e-consultation

A major concern in recent political discourse is that government has become both isolated from and unresponsive to its citizens. Democracy, by definition, demands a two-way flow of communication between government and civil society and it is now commonly argued that ICTs have the potential to facilitate such improved flows of communication--hence, e-democracy and e-consultation. The preliminary research findings presented here are part of a larger ongoing research project on e-consultation on the island of Ireland (see http://e-consultation.org). The paper initially draws on focus group discussions on the theme of (e)consultation conducted amongst activist citizens. High levels of frustration, scepticism and cynicism were expressed on the form, nature and process of extant consultation processes. The main focus addressed in this paper, however, is on how these citizens envisage ICT being used in future e-consultations. In general, most focus group participants were open to the use of ICT in future e-consultation processes but the consensus was that community groups did not currently have access to an appropriate level or range of infrastructure, technologies or skills. As a follow up to the focus group findings the research group ran a number of demonstrations on e-consultation technologies with invited activist citizens. Technologies introduced included chat room, video-conferencing, WikiPedia, WebIQ, Zing and others. The main preliminary findings and feedback from one such demonstration, and our own observations, are then presented which suggest that the potential does exist for using e-consultation technologies in local democracy and in local government to drive positive change in the government-citizen relationship. We present no na�¯ve solutions here; we merely point to some possibilities and we acknowledge that ICT alone is very unlikely to be a panacea for the declining levels of citizen participation in most democratic societies.