Software tool for mining liquid chromatography/multi‐stage mass spectrometry data for comprehensive glycerophospholipid profiling

Electrospray ionization mass spectrometry (ESI‐MS) has emerged as an indispensable tool in the field of lipidomics. Despite the growing interest in lipid analysis, there are only a few software tools available for data evaluation, as compared for example to proteomics applications. This makes comprehensive lipid analysis a complex challenge. Thus, a computational tool for harnessing the raw data from liquid chromatography/mass spectrometry (LC/MS) experiments was developed in this study and is available from the authors on request. The Profiler‐Merger‐Viewer tool is a software package for automatic processing of raw‐data from data‐dependent experiments, measured by high‐performance liquid chromatography hyphenated to electrospray ionization hybrid linear ion trap Fourier transform mass spectrometry (FTICR‐MS and Orbitrap) in single and multi‐stage mode. The software contains three parts: processing of the raw data by Profiler for lipid identification, summarizing of replicate measurements by Merger and visualization of all relevant data (chromatograms as well as mass spectra) for validation of the results by Viewer. The tool is easily accessible, since it is implemented in Java and uses Microsoft Excel (XLS) as output format. The motivation was to develop a tool which supports and accelerates the manual data evaluation (identification and relative quantification) significantly but does not make a complete data analysis within a black‐box system. The software's mode of operation, usage and options will be demonstrated on the basis of a lipid extract of baker's yeast (S. cerevisiae). In this study, we focused on three important representatives of lipids: glycerophospholipids, lyso‐glycerophospholipids and free fatty acids. Copyright © 2010 John Wiley & Sons, Ltd.     

Quantitative analysis of the mono- and sesquiterpenoids of douglas-fir sapwood by solvent extraction and gas chromatography with mass selective detection

In order to investigate the relationship between terpenoid content and black bear foraging preference, an analytical method was required to quantify mono- and sesquiterpenoids present in Douglas-fir sapwood. Sapwood samples were scraped from trees, immediately frozen in liquid nitrogen, and then homogenized. A simple extraction requiring no clean-up step was performed with ethyl acetate. Extracts were analyzed by gas chromatography with mass selective detection versus external standards. The recoveries of 22 terpenoids from fortified controls were approximately 90% with good precision (relative standard deviations of approximately 10%).     

Cyclometalated Iridium(III) Complexes Containing Semicarbazone Ligands: Synthesis,Characterization, Photophysical and Biological Studies

The synthesis, crystal structure, photophysical properties, and biological activity of the novel bis‐cyclometalated complexes [Ir(ptpy)₂(vnsc)] ( 2 ) and [Ir(ptpy)₂(acsc)] ( 3 ) [ptpy = 2‐(p‐tolyl)pyridinato, vnsc = vanillin semicarbazone, acsc = acetone semicarbazone] are described. The new compounds were prepared by the reaction of [{Ir(μ‐Cl)(ptpy)₂}₂] ( 1 ) with the corresponding semicarbazone ligands under basic conditions. The molecular structure of compound 3 was confirmed by a single‐crystal X‐ray diffraction study. The complex crystallized from chloroform as a mono‐ solvate in the orthorhombic space group Pcab with eight molecules in the unit cell.     

A Remarkably Simple Class of Imidazolium‐Based Lipids and Their Biological Properties

A series of imidazolium salts bearing two alkyl chains in the backbone of the imidazolium core were synthesized, resembling the structure of lipids. Their antibacterial activity and cytotoxicity were evaluated using Gram‐positive and Gram‐negative bacteria and eukaryotic cell lines including tumor cells. It is shown that the length of alkyl chains in the backbone is vital for the antibiofilm activities of these lipid‐mimicking components. In addition to their biological activity, their surface activity and their membrane interactions are shown by film balance and quartz crystal microbalance (QCM) measurements. The structure–activity relationship indicates that the distinctive chemical structure contributes considerably to the biological activities of this novel class of lipids.     

On the derivation and comparative analysis of large rotation shell theories

Summary For the geometrically nonlinear first approximation theory of elastic shells three energy-consistent large rotation shell variants are constructed. The governing shell equations are derived as Euler-Lagrange equations of an associated variational principle of stationary total potential energy. The numerical applicability is considered for a highly nonlinear shell problem. To incorporate the presented theories into the frame of shell models published in the literature a comparative analysis is carried out for a large number of shell equations.

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Zur Herleitung und vergleichenden Untersuchung von Schalentheorien für große Rotationen

Übersicht Im Rahmen der geometrisch-nichtlinearen ersten Schalenapproximation werden drei energiekonsistente Schalentheorien für große Rotationen hergeleitet. Die Schalengleichungen werden als Euler-Lagrange Gleichungen eines zugehörigen Variationsprinzips vom stationären Wert der potentiellen Gesamtenergie hergeleitet. Die numerische Anwendbarkeit wird anhand eines stark-nichtlinearen Schalenbeispiels nachgewiesen. Um die in dieser Arbeit hergeleiteten Theorien entsprechend einordnen zu können, wird für eine größere Zahl von in der Literatur angegebenen Schalengleichungen eine vergleichende Untersuchung mit numerischer Auswertung durchgeführt.

     

Condensation from steam—air mixtures in a horizontal annular flow channel

Experiments were performed on the condensation of steam from steam-air mixtures in annular flow at a cooled inner tube. The range of investigation was varied for laminar and turbulent flow for 1.5 × 10³ Re 1.3 × 10⁴ and inlet concentrations 0.59 p_steam/p_total 0.95. The measurements, performed at an open test loop at p_total ≈ 0.96 bar, allowed local heat and mass transfer coefficients to be evaluated for various inlet lengths in the 2 m long annulus. The steam concentration was measured locally inside the annulus with a newly developed dew-point probe. The heat flux was measured locally using the temperature gradient in the cooled inner tube.

Near the inlet region the experiments showed a slightly higher heat flux at the bottom of the tube compared to the top, although it is expected to be smaller there owing to a thicker liquid film. Far downstream from the inlet region the heat transfer at the top was higher than at the bottom. The reasons for these effects are discussed, yielding a better understanding of the thermal and fluid processes involved in condensation from vapor-gas mixtures. The measured data allow the development of correlations for predicting the local Nusselt and Sherwood numbers in a horizontal annular-flow chanbel.     

The Structure of the “Third‐Generation” Tris(pyrazolyl)borate Caesium Salt p‐BrC6H4TpCs

Slow crystallisation at lowered temperature yielded crystals of the “third‐generation” tris(pyrazolyl)borate transfer agent p‐BrC₆H₄TpCs (Tp′Cs) 1 (triclinic; P$\bar{1}$ ; a = 8.540(4), b = 15.045(6), c = 15.879(7) Å; α = 65.853(8), β = 88.457(8), γ = 75.056(8)°; V = 1791.4(13) Å³; Z = 4). The central caesium ion in 1 interacts with three individual p‐BrC₆H₄Tp ligands in two different chelating fashions.In particular, κ¹‐N‐coordination and η⁵‐π‐coordination of pyrazole moieties as well as η⁶‐π‐coordination of the p‐BrC₆H₄ substituent are observed. Further, comparable coordination of neighbouring caesium ions leads to the formation of polymeric structures connected by two bridging modes.     

Studies on photoinduced effects in pulse-electrodeposited Ag/Hg-1212/CdSe hetero-nanostructures

Metal/superconductor/semiconductor (Ag/Hg-1212/CdSe) hetero-nanostructures have been fabricated using pulse-electrodeposition technique and are characterized by X-ray diffraction (XRD), full-width at half-maximum (FWHM) and scanning electron microscopy (SEM) studies. The junction capacitance of Ag/Hg-1212, Hg-1212/CdSe and Ag/Hg-1212/CdSe heterojunctions is measured in dark and under laser irradiation at room temperature. The nature of the junction formed and built-in-junction potentials were determined. The increase in carrier concentration across the junction due to photo-irradiation has been observed.