Evaluation of a Semi-Automated Multidimensional Gas Chromatography-Infrared-Mass Spectrometry System for Irritant Analysis

The use of a semi-automated, multidimensional gas chromatography (MDGC) Fourier transform infrared (FT-IR) mass spectrometry (MS) system in the determination of components causing contact dermatitis has been investigated. Fragrances are widely used in cosmetic and household products and are the leading cause of contact dermatitis. Such products contain numerous components such as emulsifiers, thickeners, solubilizers, pigments, antioxidants, and many other compounds, which can make it difficult to isolate the compound of interest. MDGC has the capability for component analysis in such complex matrices. A semi-automated MDGC system, which consists of a commercial instrument modified in our laboratory to include two computer controlled valves and a single trap which is manually controlled was evaluated for analysis of irritants in a total of thirteen soaps. Using heartcutting techniques, components causing dermatitis were identified in eight of the thirteen soaps by examining both the infrared and mass spectra obtained and matching them with computer spectral libraries. Results from these analyses show that a baby soap and three other mild soaps were free of irritants. Irritants were identified in the remaining eight soaps. In addition, to demonstrate the versatility of the semi-automated system, the enantiomeric composition of a chiral irritant in two soaps also was determined.     

Electrical properties of r. f. sputtered thin films of CuInSe2(II). Conduction mechanism and intrinsic doping effects

An analysis of the conduction mechanism in p-type polycrystalline films of CuInSe₂ is given. It is shown that in the r.f. sputtered films the hole mobility is limited by tunneling through the grain boundary potential barrier. It is suggested that the charge carrier transport is governed by conduction through valence band states at high temperatures and by impurity band conduction at low temperatures. On the basis of the chemical composition data for the r.f. sputtered films no conclusions can be made regarding the type of the acceptor-like intrinsic defect responsible for the p-type conductivity of the films.     

Preparation of novel multifunctional amino alcohols from nitroparaffins and α,β-unsaturated aldehydes

A series of novel multifunctional amino alcohols were prepared by tandem Michael–Henry reaction by reacting nitroalkanes such as 2-nitropropane with readily available α,β-unsaturated aldehydes. The dinitro compounds were further reduced by catalytic hydrogenation to obtain respective diamines. This synthetic route provides a very convenient method of preparing multifunctional amino alcohols.     

Selective and Potent Proteomimetic Inhibitors of Intracellular Protein–Protein Interactions

Inhibition of protein–protein interactions (PPIs) represents a major challenge in chemical biology and drug discovery. α‐Helix mediated PPIs may be amenable to modulation using generic chemotypes, termed “proteomimetics”, which can be assembled in a modular manner to reproduce the vectoral presentation of key side chains found on a helical motif from one partner within the PPI. In this work, it is demonstrated that by using a library of N‐alkylated aromatic oligoamide helix mimetics, potent helix mimetics which reproduce their biophysical binding selectivity in a cellular context can be identified.     

Thermoelastic investigations for fatigue life assessment

An investigation is presented on the suitability and accuracy of a thermoelastic technique for the analysis of fatigue cracks. The stress intensity factor ranges ΔK _I and ΔK _II are determined from thermoelastic data recorded from around the tip of a sharp slot in a steel specimen under biaxial load, in order to assess the accuracy of the technique. ΔK _I and ΔK _II are determined to within 4% and 9% of a theoretical prediction, respectively. The results from a similar test on a fatigue crack under biaxial load are also presented. These show that thermoelastic stress analysis is a rapid and accurate way of analyzing mixed-mode fatigue cracks. A discussion is given on the potential of thermoelastic stress analysis of propagating cracks.     

PLS vs zeolites as sorbents and catalysts. Part 7. The role of oxide pillars and aluminosilicate sheets in alcohol dehydration on PILCs

Reactions of primary aliphatic C2-C8 alcohols on alumina and iron-aluminium-oxides pillared montmorillonite and beidellite indicate that dehydration reaction occurs on Lewis sites of pillars, while clays are responsible of cracking. This revised version was published online in June 2006 with corrections to the Cover Date.     

A new approach for second‐order perturbation theory

A new second‐order perturbation theory (MP2) approach is presented for closed shell energy evaluations. The new algorithm has a significantly lower memory footprint, a lower FLOP (floating point operations) count, and a lower time to solution compared to previously implemented parallel MP2 methods in the GAMESS software package. Additionally, this algorithm features an adaptive approach for the disk/distributed memory storage of the MP2 amplitudes. The algorithm works well on a single workstation, small cluster, and large Cray cluster, and it allows one to perform large calculations with thousands of basis functions in a matter of hours on a single workstation. The same algorithm has been adapted for graphical processing unit (GPU) architecture. The performance of the new GPU algorithm is also discussed. © 2016 Wiley Periodicals, Inc.     

A flow cytometry-based dopamine transporter binding assay using antagonist-conjugated quantum dots

Here we present the development and validation of a flow cytometry-based dopamine transporter (DAT) binding assay that uses antagonist-conjugated quantum dots (QDs). We anticipate that our QD-based assay is of immediate value to the high throughput screening of novel DAT modulators.     

Photoinduced cytotoxicity and thioadduct formation by a prodigiosin analogue

[reaction: see text] The prodigiosin alkaloid 1 and the synthetic analogue 2 show photoinduced cytotoxicity against HL-60 cancer cells. Photoirradiation of 1 and 2 causes photofading, photooxidation, and thioadduct formation. These results provide a model for the redox properties of prodigiosins that play a role in their biological activity and provide a new way to functionalize their pyrromethene entity with water-soluble thiol groups.     

Quasiparticle lifetimes due to A1 impurities in Zn

We have calculated the quasiparticle lifetimes due to Al impurities in Zn. For the Zn electronic structure we use the wave functions, Fermi velocities and surface elements calculated by Tomlinson and Swihart who based their work on the accurate pseudopotential fit to the de Haas-van Alphen data obtained by Stark and Falicov. The impurity pseudopotential form factor is obtained from the procedure developed by Shaw.