Characterization of a peptide family from the skin secretion of the Middle East Tree Frog Hyla savignyi by composition‐based de novo sequencing

A new tryptophyllin‐like peptide family was found in the skin secretion of the tree frog Hyla savignyi. Peptides were characterized by database‐independent sequencing strategies and specific ion fragmentation features were investigated. Skin secretions from specimens of Hyla savignyi were collected by mild electrical stimulation. Peptides were separated by reversed‐phase nano‐high‐performance liquid chromatography (nanoHPLC) and mass spectra were acquired online by electrospray ionization Fourier transform ion cyclotron resonance mass spectrometry (FTICR‐MS). Peptides were characterized by manual de novo sequencing and by composition‐based sequencing (CBS), appearing mostly as C‐terminal free acids and as their acid amide analogs. Amide peptides yielded lower intensities of y‐type ions after collision‐induced dissociation (CID) than their acid analogs. A mechanism of internal b‐ion formation (positive ion mode) and of CO₂ elimination (negative ion mode) is proposed. We also exemplified phenomena such as the proline effect and formation of non‐direct sequence ions after sequence rearrangements. The occurrence of rearrangement products, of internal ions and of the proline effect made the CID spectra highly complex. CBS analysis nevertheless resulted in successful and highly reliable sequence analysis. Copyright © 2010 John Wiley & Sons, Ltd.     

An extended transportation problem: a DEA-based approach

The transportation problem is an important network structured linear programming problem that arises in several contexts and that has received a great deal of attention in the literature. The existing transportation problems are limited to consideration unit of shipping cost or profit along an arc. However, in many real applications, various attributes are usually considered in a transportation problem. The current paper, proposes an extension to this problem in the presence of multiple in-commensurate inputs and outputs for each arc. The concept of relative efficiency is defined for each possible transportation plan. Two linear programming models are proposed to determine the transportation plan with the maximum efficiency. A numerical example is used to illustrate the applicability of the approach.     

Three-Component Reaction of Triphenylphosphine,Dimethyl Acetylenedicarboxylate,and Aldehyde Benzoylhydrazones: An Efficient One-Pot Synthesis of Stable Phosphorus Ylides

Protonation of the reactive 1:1 intermediate produced in the reaction between dimethyl acetylenedicarboxylate and triphenylphosphine by benzoylhydrazones leads to vinylphosphonium salts, which undergo Michael addition with the conjugate base of the NH acid to produce highly fanctionalized, salt-free phosphorus ylides in excellent yields.     

On the deformation theory of Calabi-Yau structures in strongly pseudo-convex manifolds

We study the deformation theory of Calabi-Yau structures in strongly pseudo-convex manifolds with trivial canonical bundles. Our approach could be considered as an alternative proof for a theorem of H. Laufer on the deformation of strongly pseudo-convex surfaces.     

Localization of elastic waves in heterogeneous media with off-diagonal disorder and long-range correlations

Using the Martin-Siggia-Rose method, we study propagation of acoustic waves in strongly heterogeneous media which are characterized by a broad distribution of the elastic constants. Gaussian-white distributed elastic constants, as well as those with long-range correlations with nondecaying power-law correlation functions, are considered. The study is motivated in part by a recent discovery that the elastic moduli of rock at large length scales may be characterized by long-range power-law correlation functions. Depending on the disorder, the renormalization group (RG) flows exhibit a transition to localized regime in any dimension. We have numerically checked the RG results using the transfer-matrix method and direct numerical simulations for one- and two-dimensional systems, respectively.     

Fourier Algebras on Topological Foundation *-Semigroups.

We introduce the notion of the Fourier and Fourier-Stieltjes algebras of a topological *-semigroup and show that these are commutative Banach algebras. For a class of foundation semigroups, we show that these are preduals of von Neumann algebras.     

Silica aerogel–iron oxide nanocomposites: recoverable catalysts for the oxidation of alcohols with hydrogen peroxide

Various aerogels of silica gel doped with Fe₂O₃ were prepared by sol–gel method. They were calcined to produce nanoparticle solids. The nanosized mixed oxides were active in the oxidation of alcohols and produced carbonyl compounds in very good to excellent yields using hydrogen peroxide.     

Synthesis,characterization, and molecular structures of Ni(II) and Cd(II) complexes derived from dithiophosphonate

Two novel dithiophosphonate ligands, HS₂P(p‐C₆H₄OMe)(OCH₂CH₂CH(CH₃)₂) ( 1 ) and HS₂P(p‐C₆H₄OMe)(OCH(CH₃)₂) ( 2 ), were synthesized and characterized by multinuclear (¹H, ³¹P, and ¹³C) NMR, infrared spectroscopy as well as elemental analysis. The reactions of 1 and 2 with NiCl₂·6H₂O and Cd(NO₃)₂·4H₂O in methanol led to novel complexes 3 and 4 . The single crystal X‐ray structures of 3 and 4 showed tetracoordinated structure with square planar geometry for the nickel complex, while it showed pentacoordinated structure with distorted square‐pyramid environment for the cadmium complex.     

Per Aqueous Liquid Chromatography (PALC) as a Simple Method for Native Separation of Protein A

Staphylococcal protein A (protein A) is an important protein frequently used in research studies within the fields of biomedicine and biotechnology. Due to some limitations in available protein purification methods which can hold the native structure of the protein A without changing the folding or adding histidine to structure of this protein, its separation in the native form is difficult. In this study, a new cost-effective and powerful technique was introduced for separation of the full-length and truncated forms of recombinant protein A, without any alteration in their 3D structures. Per aqueous liquid chromatography with bare silica gel stationary phase and water:acetonitrile as the mobile phase was proved to be an attractive choice among the range of separation methods. Similar to hydrophilic liquid chromatography, this method employs high percentage of water in mobile phase. The effects of mobile phase composition, pH, and salt concentration on the retention behavior of protein A on bare silica gel stationary phases were investigated. In this method, applying high amounts of aqueous solvent accompanied by a minimum percentage of organic solvent could successfully separate protein A with preservation of folding, and any affinity-tagged group such as histidine has not occurred on its structure. Purity of the fractions obtained by the proposed method was confirmed using SDS-PAGE, western blotting, and matrix-assisted laser desorption ionization time-of-flight mass spectrometry. According to the results of ELISA, separated proteins retained their ability of binding to antibody.