Voltammetric determination of citric acid and quinine hydrochloride using polypyrrole–pentacyanonitrosylferrate/platinum electrode

Cyclic voltammetry was used to investigate the electrochemical behavior of citric acid (CA) and quinine hydrochloride (QH) at a polypyrrole-pentacyanoferrate/Platinum (PPY–PCNFe/Pt) electrode in aqueous medium. The analytical plots obtained were found to be linear in the concentration range between 1.0 and 9.0 mM for both the analyte solutions. The detection limits (3δ) were found to be 1.17 × 10^?4 M and 1.08 × 10^?5 M for CA and QH analyte solutions, respectively. It was further observed that the diffusion of ionic species into and out of the polymeric film made the PPY–PCNFe/Pt electrode highly electroactive thereby enabling it to efficiently detect the analyte solutions having concentration as low as 1 mM.     

Can Agile and Traditional Systems Development Approaches Coexist? An Ambidextrous View

Emerging evidence seems to indicate that most systems development organizations are attempting to utilize both agile and traditional approaches. This study aims to understand the reasons organizations feel the need for this unlikely juxtaposition and the organizational challenges in sustaining the opposing cultures. Drawing on the extensive literature in organizational theory and management, we advocate ambidexterity as a viable solution to systems development organizations attempting to harness the benefits of both agile and traditional development.     

A survey on resource allocation in high performance distributed computing systems

An efficient resource allocation is a fundamental requirement in high performance computing (HPC) systems. Many projects are dedicated to large-scale distributed computing systems that have designed and developed resource allocation mechanisms with a variety of architectures and services. In our study, through analysis, a comprehensive survey for describing resource allocation in various HPCs is reported. The aim of the work is to aggregate under a joint framework, the existing solutions for HPC to provide a thorough analysis and characteristics of the resource management and allocation strategies. Resource allocation mechanisms and strategies play a vital role towards the performance improvement of all the HPCs classifications. Therefore, a comprehensive discussion of widely used resource allocation strategies deployed in HPC environment is required, which is one of the motivations of this survey. Moreover, we have classified the HPC systems into three broad categories, namely: (a) cluster, (b) grid, and (c) cloud systems and define the characteristics of each class by extracting sets of common attributes. All of the aforementioned systems are cataloged into pure software and hybrid/hardware solutions. The system classification is used to identify approaches followed by the implementation of existing resource allocation strategies that are widely presented in the literature.     

Temperature-induced control over phase selection among hydroxides of nickel

While at low (4°C) temperatures, addition of ammonia to aqueous metal nitrate solutions induces the precipitation of α-nickel hydroxide and at high (25–65°C) temperatures, β-Ni(OH)₂ is formed. The crystallinity of the product improves at higher temperatures of precipitation and the product obtained at 65°C is devoid of various disorders such as stacking faults, turbostraticity and interstratification. This provides a simple and efficient alternative to the hydrothermal synthesis of crystalline β-Ni(OH)₂. The temperature induced control over phase selection provides direct experimental evidence for the metastability of α-nickel hydroxide. Crystalline β-Ni(OH)₂ is, however, a poor electrode material for alkaline secondary cells and exhibits a capacity of only 75 ± 10 mAh/g, against the theoretically expected 289 mAh/g.     

Electron-electron scattering and ultrasonic attenuation in potassium

The electron-electron scattering contribution to the ultrasonic attenuation in potassium at low temperatures is evaluated using the Landau Fermi liquid theory. The scattering function is evaluated using the approximation suggested by MacDonald and Geldart. The results are compared with theoretically evaluated electron-phonon scattering contributions. The results show that the electron-electron scattering contribution is of the same order as the electron-phonon scattering contribution in the 2–5 K range. Below 2 K the electron-electron scattering predominates.     

Microwave‐assisted facile and convenient synthesis of fatty acid amide (erucamide): Chemical‐catalyzed rapid method

The present investigation explores a process for the production of erucamide, utilizing microwave irradiation as the heating element for the reaction between erucic acid and gaseous ammonia liberated by urea in the presence of catalyst (di‐ammonium hydrogen ortho‐phosphate) at atmospheric pressure and high temperature. In this process, the time of reaction is very short (25 min) and the yield is also good (92%).     

Fluorescence spectroscopic studies on interactions between liver annexin VI and nucleotides--a possible role for a tryptophan residue

Annexin VI is a 68-kDa calcium-, phospholipid-, and cytoskeletal-element-binding protein, which has been implicated in various processes, including calcium release and sequestration in calcifying cartilage, in a receptor-mediated endocytosis in human fibroblasts, and in secretion from chromaffin granules. In these processes it was found that, in addition to Ca2+ and annexin, the presence of ATP is also a prerequisite. In the present report we show that annexin VI binds ATP and the binding of nucleotide to protein is accompanied by quenching of an intrinsic fluorescence of annexin VI, which was found to be specific for 2'-(or 3')-O-(2,4,6-trinitrophenyl)adenosine 5'-triphosphate, GTP and ATP, and dependent on the annexin conformation. The nucleotide-binding site within an annexin VI molecule is likely to be close to the tryptophan-containing domain of annexin VI. We propose that ATP plays the role of a physiological ligand for annexin VI, and its binding to annexin VI may represent an alternative cellular mechanism for the regulation of annexin-membrane interactions coupled to overall energy transitions in the cell.     

Weathering grade classification of lesser Himalayan granites,Western India

Lesser Himalayan granites show various stages of weathering. Primary cracks, grain boundaries and joints have initiated and controlled the weathering processes and resulted in the decomposition of the granites. Feldspars and mica act as key minerals for the initiation of weathering. Later stages of weathering are dominated by the varying nature of weathered clay.     

Structural and thermodynamic consequences of introducing {{alpha}}-aminoisobutyric acid in the S peptide of ribonuclease S

The S protein–S peptide interaction is a model systemto study binding thermodynamics in proteins. We substitutedalanine at position 4 in S peptide by