Direct synthesis of 1,1'-[1,4-phenylenebis(methylene)]-bis- 1,4,8,11-tetraazacyclotetradecane octahydrochloride (AMD 3100) without the use of protecting groups

A four-step synthesis of the title compound starting from methyl acrylate, ethylenediamine, and dimethyl malonate is reported. The synthesis can be run on a multigram scale and is operationally simple. The use of protecting groups is avoided by utilizing the trioxocyclam as the key coupling intermediate.     

High-resolution ion mobility separations coupled to mass spectrometry: What's next?

Herein, I provide a personal perspective on high-resolution multipass ion mobility spectrometry-mass spectrometry (IMS-MS), with a specific emphasis on cyclic (cIMS) and structures for lossless ion manipulations (SLIM IMS)-based separations. My overarching goal for this perspective was to detail what I believe will be the key important areas in which IMS-MS will help shape the bioanalytical community and especially omics-based research.     

Dark matter: The leptonic connection

Recent observations of high-energy positrons and electrons by the PAMELA and ATIC experiments may be an indication of the annihilation of dark matter into leptons and not quarks. This leptonic connection was foreseen already some years ago in two different models of radiative neutrino mass. We discuss here the generic interactions (νη⁰−lη⁺)χ$(\nu {\eta }^0-l{\eta }^{+})\chi$ and lcζ⁻χc$l^c{\zeta }^{-}{\chi }^c$ which allow this to happen, where χ   and/or χc${\chi }^c$ are fermionic dark-matter candidates. We point out in particular the importance of χχ→l⁺l⁻γ$\chi \chi \to l^{+}{l}^{-}\gamma$ to both positron and gamma-ray signals within this framework.     

Absorption enhancement of oligothiophene dyes through the use of a cyanopyridone acceptor group in solution-processed organic solar cells

Improvements in the performance of small molecule-based organic solar cells have been reported through the use of a cyanopyridone acceptor group. This acceptor fragment enhances the absorbance of an oligothiophene-based dye and enables the addition of a solubilising alkyl chain that facilitates simple device fabrication from solution.     

Nanowell-mediated multidimensional separations combining nanoLC with SLIM IM-MS for rapid,high-peak-capacity proteomic analyses

Mass spectrometry (MS)–based analysis of complex biological samples is essential for biomedical research and clinical diagnostics. The separation prior to MS plays a key role in the overall analysis, with separations having larger peak capacities often leading to more identified species and improved confidence in those identifications. High-resolution ion mobility (IM) separations enabled by Structures for Lossless Ion Manipulation (SLIM) can provide extremely rapid, high-resolution separations and are well suited as a second dimension of separation following nanoscale liquid chromatography (nanoLC). However, existing sample handling approaches for offline coupling of separation modes require microliter-fraction volumes and are thus not well suited for analysis of trace biological samples. We have developed a novel nanowell-mediated fractionation system that enables nanoLC-separated samples to be efficiently preconcentrated and directly infused at nanoelectrospray flow rates for downstream analysis. When coupled with SLIM IM-MS, the platform enables rapid and high-peak-capacity multidimensional separations of small biological samples. In this study, peptides eluting from a 100 nL/min nanoLC separation were fractionated into ~ 60 nanowells on a microfluidic glass chip using an in-house–developed robotic system. The dried samples on the chip were individually reconstituted and ionized by nanoelectrospray for SLIM IM-MS analysis. Using model peptides for characterization of the nanowell platform, we found that at least 80% of the peptide components of the fractionated samples were recovered from the nanowells, providing up to ~tenfold preconcentration for SLIM IM-MS analysis. The combined LC-SLIM IM separation peak capacities exceeded 3600 with a measurement throughput that is similar to current one-dimensional (1D) LC-MS proteomic analyses.

A nanowell-mediated multidimensional separation platform that combines nanoLC with SLIM IM-MS enables rapid, high-peak-capacity proteomic analyses.

     

Preparation of reactive polymeric nanoparticles (RPNPs)

A series of reactive polymeric nanoparticles (RPNPs) was prepared by free radical nonlinear copolymerization of mono (M ₁) and trivinyl acrylic (M ₂) monomers in miniemulsion. The crosslinking density was determined by the mole ratio of the trivinyl component. It was found that the unswelled latex nanoparticles showed a narrower dispersity than in the organic solution of macromolecules. In latex, the size increased with the ratio of M ₂ monomer due to its higher polarity in the aqueous medium. However, the swollen nanoparticles, dissolved or dispersed in organic solvent, showed a higher dispersity as a function of composition and the crosslinking density. The residual vinyl groups adjacent to the nanoparticles were subjected to further crosslinking reactions. The reactive vinyl groups were detected by nuclear magnetic resonance spectroscopy (NMR). The size of particles in swollen state was determined by dynamic laser light scattering (DLS) method and the dried form by scanning electron microscopy (SEM). It was found that size of RPNPs is in the range of 50 to 500 nm. These particles possess properties that may allow their application in areas as disparate as dental filling material and as a component in industrial powder-based coatings.     

Double grating interferometers II. Application to collimated beams

The application of a shearing interferometer consisting of two identical gratings to measurements of the aberrations of collimated beams is described. The theory of the system is derived, and it is shown how the shear as well as the tilt between the sheared wavefronts can be varied.