Characterisation of Commercial Vodkas by Solid-Phase Microextraction and Gas Chromatography/Mass Spectrometry Analysis

A reliable method for the characterisation of vodkas has been developed by application of solid-phase microextraction (SPME) and gas chromatography/mass spectrometry (GCMS). Sixty-four samples of commercial Canadian and American vodkas, and one sample each of Japanese and German vodkas, were investigated in this study. The procedure yielded reproducible chromatographic profiles. The detected components were ethyl esters of C₈ to C₁₈ fatty acids at μg litre⁻¹ levels, various additives and contaminants. Distinctive profiles were observed for various brands. Markers for differentiating between Canadian and American vodkas were identified. The results of this study indicate that vodkas are differentiated by the combined effects of the original raw materials, any added substances, and differences in processing.     

Characterization of nonionic and cationic amine-functional polymers by aqueous SEC-MALLS

Molecular weight, root-mean-square radius, and conformational information obtained from aqueous size exclusion chromatography (SEC) and multiangle laser light-scattering (MALLS) detection are examined for amine-functional polymers. These include homopolymers and copolymers of poly(ethenylformamide) and cationic poly(vinylamine). Light-scattering studies for poly(ethenylformamide) employing 15 angles of detection are used to calculate molecular weights as high as 700,000 daltons with a root-mean-square radius of nearly 50 nm. Calculated conformational coefficients indicate a random-coil configuration at low molecular weights and a more compacted conformation at high molecular weights. Molecular weights and root-mean-square radius values for cationic poly(vinylamine) are determined using a three-angle MALLS detector. Root-mean-square radius is strongly dependent on the ionic strength of the mobile phase. Cationic poly(vinylamine) exhibits a rod-like conformation at both low and high ionic strength. Explanations are proposed for this behavior. © 1996 John Wiley & Sons, Inc.     

An analysis of failure-time distributions for product design optimization

Analysis of experimental data is often a problem facing design and manufacturing engineers. Many experiments are run for the express purpose of making a decision between manufacturing process or material alternatives. Statisticians recommend replication in experimental design; however, methods of analysing experimental data, as presented in a majority of engineering curricula, generally review only the most basic situations (checking for a statistically significant difference between the means or variances of two samples, for example). If means and variances change with time, group comparisons may require more sophisticated analyses. This paper presents one method that takes into account shifts in group means and variances over time. Resistance temperature sensor drift data generated from six different design configurations are used as an illustration. This procedure takes into account all drift path information from multiple sensors in multiple groups.     

Effect of silane coupling agent on the chemorheological behaviour of epoxidised natural rubber filled with precipitated silica

Results of measurements of physical properties and solvent swelling of the extrudates indicate that epoxidised natural rubber (ENR) interacts chemically with precipitated silica when the mix of the two was extruded at 150–170°C in a Monsanto Processability Tester (MPT). The extent of interaction between the rubber and the filler depends on the extrusion time, the volume fraction of the filler, the shear rate and the addition of the silane coupling agent, namely N-3-(N-vinyl benzyl amino) ethyl-γ-amino propyl trimethoxy silane monohydrochloride. The activation energy of the chemical interaction between ENR and silica decreases on the addition of the silane coupling agent.     

Task-Related Differences in the Cuticular Hydrocarbon Composition of Harvester Ants, Pogonomyrmex barbatus

Colonies of the harvester ant, Pogonomyrmex barbatus, perform a variety of tasks. The behavior of an individual worker appears to depend on its recent history of brief contacts with ants of the same and other task groups. The purpose of this study was to determine whether task groups differ in cuticular hydrocarbon composition. We compared the cuticular hydrocarbon composition of ants collected under natural conditions as they performed one of three tasks: patrolling (locating food sources), foraging, or nest maintenance. Task groups differed significantly in the relative proportions of classes of hydrocarbon compounds, as well as in individual compounds. Relative to nest maintenance workers, foragers and patrollers had a higher proportion of straight-chain alkanes relative to monomethylalkanes, dimethylalkanes, and alkenes. There was no significant difference in the chain length of n-alkanes among the task groups. Foragers did not differ in hydrocarbon composition from patrollers. Colonies differed significantly from one another in hydrocarbon composition, but task groups differed in consistent ways from colony to colony, suggesting that the mechanism responsible for task-related hydrocarbon composition was the same in all colonies. P. barbatus workers switch tasks during their lifetimes, suggesting that cuticular hydrocarbon composition changes during adulthood as well. Nest maintenance workers are probably younger than foragers and patrollers and perform very little of their work outside of the nest. Task-related hydrocarbon differences detected here may be associated with worker age, and/or the abiotic characteristics (temperature, humidity, and ultraviolet light) of the interior and exterior work environments.     

Producing titanium powder by continuous vapor-phase reduction

One of the goals of the U.S. Department of Energy’s Albany Research Center is to reduce the cost of titanium parts by developing a continuous titanium process. In this work, titanium powder was produced by feeding liquid TiCl₄, with argon as a carrier gas, and magnesium wire into a shaft reactor at 1,000°C. The magnesium and TiCl₄ vaporized and reacted to produce a mixture of titanium, MgCl₂, and magnesium powder. Ti/Mg/MgCl₂ powder was removed from the argon gas stream by an electrostatic precipitator, and the titanium powder was separated from the magnesium and MgCl₂ by either vacuum distillation or leaching. Vacuum distillation produced sintered titanium powder with lower oxygen levels, but unacceptably high levels of magnesium and chlorine. Leached powder was spherical and free-flowing with low levels of magnesium and chlorine, but the oxygen content was no lower than 0.82%. The high oxygen content of the leached powder is caused by surface oxidation of the submicrometer titanium powder. For more information, contact S.J. Gerdemann, Albany Research Center-Department of Energy, 1450 Queen Avenue S.W., Albany, Oregon 97321-2198; (541) 967-5964; fax (541) 967-5868; e-mail gerdeman@alrc.doe.gov.     

Perfluorocyclobutane aromatic ether polymers. III. Synthesis and thermal stability of a thermoset polymer containing triphenylphosphine oxide

The preparation of a novel triaryl phosphine oxide thermoset polymer containing the perfluorocyclobutane linkage is described. The synthetic methodology involves the formation of a Grignard reagent from 4-bromotrifluorovinyloxybenzene and reaction with phosphorous trichloride to form the triaryl phosphine trifluorovinyl ether monomer. Oxidation of the phosphine monomer with hydrogen peroxide in ethanol provides quantitative conversion of the phosphine to the phosphine oxide. Analysis of the thermal decomposition of the resulting polymer in both nitrogen and air indicates improvement in thermal and thermal/oxidative stability with respect to the previously reported polymer prepared from 1,1,1-tris(4-trifluorovinyloxy)phenyl ethane. Differences in thermal and thermal/oxidative performance still exist, indicating that oxidative processes contribute to the polymer decomposition in air. © 1998 John Wiley & Sons, Inc. J Appl Polym Sci 69: 2005–2012, 1998     

Kinetics of trifluorovinyl ether cyclopolymerization via Raman spectroscopy

Polymerization kinetics of tris(trifluorovinyloxyphenyl)ethane (TVE) in the bulk are characterized by measuring the disappearance of the fluoro-olefin Raman signal at 1831cm^-1 normalized to an aromatic ring signal as an internal standard. The nth order kinetic model (dx/dt = k(1 − x)ⁿ) was applied to determine a reaction order of 2·0. Reaction rates below 85% conversion measured for various temperatures ranged from 2·2×10^-3min^-1 (t_1/2 = 454 min) to 3·1×10^-1min^-1 (t_1/2 = 3·3 min) for 130°C and 210°C, respectively. Above 85% olefin conversion, second order rate constants deviated from linearity as gelation ensued. An Arrhenius activation energy of 24·6 kcalmol^-1 was determined. The non-destructive Raman technique was found to be an excellent method for measuring the cure kinetics in the bulk and may be applicable to ‘on-line’ needs for general application of perfluorocyclobutane (PFCB) polyarylether materials. © 1998 SCI.     

Computer‐Guided Design,Synthesis, and Biological Evaluation of Quinoxalinebisarylureas as FLT3 Inhibitors

Activating mutations of FMS‐like tyrosine kinase 3 (FLT3) are present in ～30 % of patients with acute myeloid leukemia (AML) and are associated with poor prognosis. Point mutations in the tyrosine kinase domain (TKD) are observed as primary mutations or are acquired as secondary mutations in FLT3 with internal tandem duplications (ITDs) after treatment with tyrosine kinase inhibitors (TKIs). Although dozens of potent inhibitors against FLT3 ITD have been reported, activating TKD point mutations, especially at residues F691 and D835, remain the leading cause for therapy resistance, highlighting the consistent need for new potent inhibitors. Herein we report the identification and characterization of novel quinoxaline‐based FLT3 inhibitors. We used the pharmacophore features of diverse known inhibitors as a starting point for a new optimization algorithm for type II TKIs, starting from an in silico library pharmacophore search and induced‐fit docking in the known FLT3 structure. This led to the design of a set of diverse quinoxalinebisarylureas, which were profiled in an FLT3 kinase activity assay. The most promising compounds were further evaluated in a zebrafish embryo phenotype assay.     

Antimicrobial properties of commercial annatto extracts against selected pathogenic, lactic acid, and spoilage microorganisms

Annatto preparations are used to impart distinctive flavor and color to foods and are a primary colorant in dairy foods such as cheese and butter. There are several reports indicating that certain fractions of the annatto plant have biological activities against microorganisms of significance in food fermentation, food preservation, and human health. However, little is reported describing the nature of the antimicrobial compound(s) or their potential presence in commercial annatto colorant preparations. This study was conducted to determine whether commonly available annatto extracts are capable of influencing the outgrowth of selected lactic acid, spoilage, and pathogenic microorganisms. Disk diffusion and tube macrodilution techniques were used to determine the MICs and MBCs of double-strength water-soluble annatto extracts. Standard antibiotic disks were used as controls for the disk diffusion assay. The results demonstrate that annatto has an inhibitory effect on Bacillus cereus, Clostridium perfringens, and Staphylococcus aureus, with MICs of 0.08, 0.31, and 0.16% (vol/vol) and diameters of inhibition of 9 to 10, 12 to 13, and 15 to 16 mm, respectively. A concentration of 0.63% (vol/vol) inhibited the growth of Streptococcus thermophilus, Lactobacillus casei subsp. casei, Lactococcus lactis, and Paenibacillus polymyxa. The MICs for Listeria monocytogenes and Enterococcus durans were 1.25 and 2.5% (vol/vol), respectively. No activity was detected against Lactobacillus plantarum, Bifidobacterium bifidum, yeasts, or selected gram-negative bacteria.