Freezing Transition of Random Heteropolymers Consisting of an Arbitrary Set of Monomers

Mean field replica theory is employed to analyze the freezing transition of random heteropolymers comprised of an arbitrary number ($q$) of types of monomers. Our formalism assumes that interactions are short range and heterogeneity comes only from pairwise interactions, which are defined by an arbitrary $q \times q$ matrix. We show that, in general, there exists a freezing transition from a random globule, in which the thermodynamic equilibrium is comprised of an essentially infinite number polymer conformations, to a frozen globule, in which equilibrium ensemble is dominated by one or very few conformations. We also examine some special cases of interaction matrices to analyze the relationship between the freezing transition and the nature of interactions involved.Comment: 30 pages, 1 postscript figur

N-p-Chlorophenyl-2-thenohydroxamic Acid a Sensitive Reagent for Spectrophotometric Determination of Vanadium

The solvent extraction and spectrophotometric determination of vanadium(V) with N-p-chlorophenyl-2-thenohydroxamic acid (CPTHA) is described. The absorption spectrum of the vanadium(V)- CPTHA extracts in chloroform, from 4 mol/dm3 hydrochloric acid has its absorbance maximum at 530 nm; the reagent being colourless does not absorb at this wavelength. The coloured system obeys Beer\u27s law over a wide range. The molar absorptivity in terms of vanadium is 5500 dm3 mo1-1 cm-1 at 530 nm. The optimum acid range for quantitative extraction of the chelate is 3 to 9 mol/dm3 hydrochloric acid. The method is free from the interference of iron(III) and several other alloying elements which are often associated with vanadium. The method has been successfully used for determination of vanadium in BCS steels

N-p-Chlorophenyl-2-thenohydroxamic Acid a Sensitive Reagent for Spectrophotometric Determination of Vanadium

The solvent extraction and spectrophotometric determination of vanadium(V) with N-p-chlorophenyl-2-thenohydroxamic acid (CPTHA) is described. The absorption spectrum of the vanadium(V)- CPTHA extracts in chloroform, from 4 mol/dm3 hydrochloric acid has its absorbance maximum at 530 nm; the reagent being colourless does not absorb at this wavelength. The coloured system obeys Beer\u27s law over a wide range. The molar absorptivity in terms of vanadium is 5500 dm3 mo1-1 cm-1 at 530 nm. The optimum acid range for quantitative extraction of the chelate is 3 to 9 mol/dm3 hydrochloric acid. The method is free from the interference of iron(III) and several other alloying elements which are often associated with vanadium. The method has been successfully used for determination of vanadium in BCS steels

Dendrimer-Encapsulated Nanoparticles: New Synthetic and Characterization Methods and Catalytic Applications

In this article we describe the synthesis, characterization, and applications of dendrimer-encapsulated nanoparticles (DENs). These materials are synthesized using a template approach in which metal ions are extracted into the interior of dendrimers and then subsequently reduced chemically to yield nearly size-monodisperse particles having diameters in the 1-2 nm range. Monometallic, bimetallic (alloy and core@shell), and semiconductor nanoparticles have been prepared by this route. The dendrimer component of these composites serves not only as a template for preparing the nanoparticle replica, but also as a stabilizer for the nanoparticle. In this perspective, we report on progress in the synthesis, characterization, and applications of these materials since our last review in 2005. Significant advances in the synthesis of core@shell DENs, characterization, and applications to homogeneous and heterogeneous catalysis (including electrocatalysis) are emphasized.U.S. Department of Energy, Office of Basic Energy Sciences DE-FG02-09ER16090U.S. National Science Foundation 0847957Robert A. Welch Foundation F-0032Chemistr

Is Heteropolymer Freezing Well Described by the Random Energy Model?

It is widely held that the Random Energy Model (REM) describes the freezing transition of a variety of types of heteropolymers. We demonstrate that the hallmark property of REM, statistical independence of the energies of states over disorder, is violated in different ways for models commonly employed in heteropolymer freezing studies. The implications for proteins are also discussed.Comment: 4 pages, 3 eps figures To appear in Physical Review Letters, May 199

Gunrock: A High-Performance Graph Processing Library on the GPU

For large-scale graph analytics on the GPU, the irregularity of data access and control flow, and the complexity of programming GPUs have been two significant challenges for developing a programmable high-performance graph library. "Gunrock", our graph-processing system designed specifically for the GPU, uses a high-level, bulk-synchronous, data-centric abstraction focused on operations on a vertex or edge frontier. Gunrock achieves a balance between performance and expressiveness by coupling high performance GPU computing primitives and optimization strategies with a high-level programming model that allows programmers to quickly develop new graph primitives with small code size and minimal GPU programming knowledge. We evaluate Gunrock on five key graph primitives and show that Gunrock has on average at least an order of magnitude speedup over Boost and PowerGraph, comparable performance to the fastest GPU hardwired primitives, and better performance than any other GPU high-level graph library.Comment: 14 pages, accepted by PPoPP'16 (removed the text repetition in the previous version v5

A retrospective analysis comparing functional and radiological outcomes after treatment of unstable distal radius fractures using volar locked plate versus percutaneous fixation

Background: Distal radius fractures are one of the most routinely encountered injuries in an orthopaedic setting. Despite the wide variety of treatment options available there is still debate about the optimal way to treat these fractures. The aim was to evaluate and compare functional and radiological outcomes of unstable distal radius fractures treated by either by using volar locking compression plating (VLP) or by using percutaneous fixation augmented by Kirschner (K) wires (EF).Methods: A retrospective analysis was carried out on all cases of acute unstable unilateral fracture distal radius who were admitted between January 2015 and December 2017 and were treated either by VLP or EF. QuickDASH score and PRWE were documented at every follow up in OPD at 6 weeks, 6 months and 1 year post-op along with serial X-rays at immediate post-op and 01 year which were then compared.Results: A total of 122 cases of fracture distal radius were selected for study which fulfilled the inclusion criteria out of which 49 were treated by VLP and 73 by EF. There was no statistical difference in QuickDASH, PRWE scores or wrist ROM between two groups at1 year follow up. However VLP group was better in maintaining palmar tilt, radial length and inclination at the end of 1 year.Conclusions: Both VLP and EF show comparable and predictable good outcomes in treating unstable distal radius fractures when measured in terms of ROM and clinically validated patient outcome scores at 01 year follow up with similar rate of complications.

Primary Sequences of Protein-Like Copolymers: Levy Flight Type Long Range Correlations

We consider the statistical properties of primary sequences of two-letter HP copolymers (H for hydrophobic and P for polar) designed to have water soluble globular conformations with H monomers shielded from water inside the shell of P monomers. We show, both by computer simulations and by exact analytical calculation, that for large globules and flexible polymers such sequences exhibit long-range correlations which can be described by Levy-flight statistics.Comment: 4 pages, including 2 figures; several references added, some formulations improve

Connecting Localism and Community Empowerment: Research Review and Critical Synthesis for the AHRC Connected Community Programme

The Connecting Localism and Community Empowerment project sought to assess the merits of the assumption that localisms brings about community empowerment through a review of the existing academic and policy literatures. The key findings from the review point towards a lack of clarity and coherence in the literature in the usage and interpretations of the terms ‗localism‘ and ‗community empowerment‘. They are often defined by implication or tacitly assumed to have an accepted definition. Whilst greater localism is generally claimed to increase community empowerment, there are substantive grounds for questioning this claim, which arise from critically analysing these concepts and how they interact. These grounds highlight conditions which need to be fulfilled if localism is to realise its potential to enhance community empowerment. To understand these conditions we analysed four international case studies. We also consider two assessments of the New Labour government‘s localist policies in the UK

Two State Behavior in a Solvable Model of β\beta-hairpin folding

Understanding the mechanism of protein secondary structure formation is an essential part of protein-folding puzzle. Here we describe a simple model for the formation of the $\beta$-hairpin, motivated by the fact that folding of a $\beta$-hairpin captures much of the basic physics of protein folding. We argue that the coupling of ``primary'' backbone stiffness and ``secondary'' contact formation (similar to the coupling between the ``secondary'' and ``tertiary'' structure in globular proteins), caused for example by side-chain packing regularities, is responsible for producing an all-or-none 2-state $\beta$-hairpin formation. We also develop a recursive relation to compute the phase diagram and single exponential folding/unfolding rate arising via a dominant transition state.Comment: Revised versio