252Cf-plasma desorption and cesium-ion liquid secondary-ion mass spectrometric analysis of recombinant proteins.

The 35 keV Cs+ liquid secondary-ion mass spectrometry (LSIMS) and 252Cf-plasma desorption (PD) mass spectra of recombinant proteins in the 10-25 kDa mass range are compared. Both techniques showed comparable mass accuracy and sensitivity, and in the case of LSIMS, remarkably short analysis time. Analysis by the PD/nitrocellulose method demonstrated slightly higher sensitivity and relatively lower dependence on the salt and buffer content of the protein sample.     

Mass spectrometric mapping of disulfide bonds in recombinant human interleukin-13

Interleukin 13 (IL-13), a member of the a-helical family of cytokines, has approximately 30% primary sequence homology with IL-4 and shares a common receptor component. The biologically active rhIL-13 is monomeric and non-glycosylated, and contains two disulfide bonds as determined by comparative electrospray mass spectrometric (MS) analysis of the protein before and after reduction with dithiothreitol-dithioerythritol. A trypsin-resistant core peptide of rhIL-13 was isolated and analyzed by plasma desorption (PD) MS, identifying a disulfide-linked core peptide. Subsequent digestion of this core peptide by pepsin, followed by PDMS analysis of the resulting cystine-containing peptic fragments, provided rapid determination of the existing disulfide bonds between cysteine residues 28-56 and 44-70. This disulfide arrangement is similar to that observed for the analogous four internal cysteine residues in hIL-4. The conservation of disulfide bond arrangements between hIL-13 and hIL-4, coupled with their alpha-helical structure and sequence homologies, confirms that IL-13 and IL-4 are structural homologues. It is also consistent with their reported similarities in biological function and receptor binding kinetics.     

Synthesis of multi-functionalized benzofurans through the condensation of ninhydrin and phenols using SSA as a recyclable heterogeneous acid catalyst

A simple and efficient one-pot methodology has been developed for the synthesis of biologically important multi-functionalized 3-(2\(^{\prime }\)-hydroxyaryl)-2-(2\(^{\prime }\)-carboxyphenyl)benzofurans using silica sulfuric acid (SSA) as a heterogeneous acid catalyst in DMF medium. The significant advantages of this methodology are the use of SSA as a recyclable solid acid catalyst, operational simplicity, easy availability of the starting materials, and good yield of the products with high atom-economy.     

Kakeya-Type Sets Over Cantor Sets of Directions in $$\mathbb {R}^{d+1}$$

Given a Cantor-type subset \(\Omega \) of a smooth curve in \(\mathbb R^{d+1}\), we construct examples of sets that contain unit line segments with directions from \(\Omega \) and exhibit analytical features similar to those of classical Kakeya sets of arbitrarily small \((d+1)\)-dimensional Lebesgue measure. The construction is based on probabilistic methods relying on the tree structure of \(\Omega \), and extends to higher dimensions an analogous planar result of Bateman and Katz (Math Res Lett 15(1):73–81, 2008). In contrast to the planar situation, a significant aspect of our analysis is the classification of intersecting tube tuples relative to their location, and the deduction of intersection probabilities of such tubes generated by a random mechanism. The existence of these Kakeya-type sets implies that the directional maximal operator associated with the direction set \(\Omega \) is unbounded on \(L^p(\mathbb {R}^{d+1})\) for all \(1\le p<\infty \).     

Efficient Synthesis of Fully Substituted and Diversely Functionalized Pyrazoles through p-TSA Catalyzed One-Pot Condensation of Cyclic β-Diketones,Arylglyoxals and Arylhydrazones

A one-pot, three-component, and atom economic synthesis of biologically and pharmaceutically important fully substituted and functionalized pyrazole derivatives has been accomplished under metal-catalyst-free benign conditions. The strategy involves early condensation of readily available cyclic β-diketones (dimidone, 4-hydroxycoumarin and 2-hydroxy-1,4-naphthoquinone) and arylglyoxals to generate a chalcone type intermediate which upon acid catalyzed condensation with ambident nucleophile arylhydrazones produces various aryl and cyclic β-diketone substituted pyrazole derivatives. The synthesis embraces high functional group tolerance, broad substrate scope, excellent yield of the products, short reaction time and operationally simple and mild reaction conditions. The synthesis provides an easy opportunity of incorporating biologically important N-diarylsulfide/selenide functionality, various enolisable cyclic β-diketones and other bioactive heterocycles concurrently to pyrazole, which may help in designing and development of pyrazole derivatives of pharmacological significance.     

Dehydrogenative Silylation of Alcohols Under Pd-Nanoparticle Catalysis

Pd-nanoparticle-catalyzed dehydrogenative coupling between various hydrosilanes and alcohols was shown to provide silyl ethers in good and reproducible yields. The synthetic methodology is effective for a wide range of simple and bulky silanes and secondary alcohols, while keeping various other functional groups intact. The procedure also exhibits high selectivity for the silylation of primary versus secondary alcohols in 1,2-diols, and allows the successive silylation of alkynols and hydrogenation of the triple bond to afford Z-alkenols in good yields.     

Solvent free,fast and asymmetric Michael additions of ketones to nitroolefins using chiral pyrrolidine–pyridone conjugate bases as organocatalysts

New chiral organocatalysts are envisaged based on a pyrrolidine–pyridone conjugate and synthesized from commercially available proline employing standard protocols. These catalysts were found to be useful for asymmetric Michael additions of ketones to nitroolefins to afford the desired products in very good yields (up to 98%) with excellent diastereo- and enantioselectivities (>97:3 syn/anti and up to 98% ee) in very short reaction time compared with the existing reports.     

Structure of high-Tc superconducting Bi-Sr-Ca-Cu-O films prepared by spray pyrolysis

High-T_c superconducting films of Bi-Sr-Ca-Cu-O have been synthesized by spray pyrolysis of nitrate precursors onto yttria stabilized zirconia (YSZ), followed by rapid annealing at 840°C in air/oxygen. The films are preferentially oriented with c-axis parallel to the plane of the substrate surface. The diffraction patterns of the films correspond to a mixed phase orthorhombic structure, with different c-values of 24.49 Å, 30.78 Å and 37.25 Å. These films exhibit superconductivity at 91 K and zero resistance at 77 K.     

A solution growth technique for the preparation of copper (II) selenide thin films

A solution growth technique has been developed for the deposition of thin films of copper(II) selenide on glass substrate using a copper(II) salt solution, triethanolamine, ammonia, and sodium selenosulfate as the reacting agents. The material has been characterized through X-ray powder photography, optical absorption, and Hall measurements at room temperature. The films are found to be degenerate and p type with a Moss-Burstein shifted direct band gap of 2.14 eV.