Preliminary Study on the Differences in Hydrocarbons Between Phosphine-Susceptible and -Resistant Strains of Rhyzopertha dominica (Fabricius) and Tribolium castaneum (Herbst) Using Direct Immersion Solid-Phase Microextraction Coupled with GC-MS.

Phosphine resistance is a worldwide issue threatening the grain industry. The cuticles of insects are covered with a layer of lipids, which protect insect bodies from the harmful effects of pesticides. The main components of the cuticular lipids are hydrocarbon compounds. In this research, phosphine-resistant and -susceptible strains of two main stored-grain insects, T. castaneum and R. dominica, were tested to determine the possible role of their cuticular hydrocarbons in phosphine resistance. Direct immersion solid-phase microextraction followed by gas chromatography-mass spectrometry (GC-MS) was applied to extract and analyze the cuticular hydrocarbons. The results showed significant differences between the resistant and susceptible strains regarding the cuticular hydrocarbons that were investigated. The resistant insects of both species contained higher amounts than the susceptible insects for the majority of the hydrocarbons, sixteen from cuticular extraction and nineteen from the homogenized body extraction for T. castaneum and eighteen from cuticular extraction and twenty-one from the homogenized body extraction for R. dominica. 3-methylnonacosane and 2-methylheptacosane had the highest significant difference between the susceptible and resistant strains of T. castaneum from the cuticle and the homogenized body, respectively. Unknown5 from the cuticle and 3-methylhentriacontane from the homogenized body recorded the highest significant differences in R. dominica. The higher hydrocarbon content is a key factor in eliminating phosphine from entering resistant insect bodies, acting as a barrier between insects and the surrounding phosphine environment.

Pollutant emissions from gasoline combustion. 1. Dependence on fuel structural functionalities.

To study the formation of air pollutants and soot precursors (e.g., acetylene, 1,3-butadiene, benzene, and higher aromatics) from aliphatic and aromatic fractions of gasoline fuels, the Utah Surrogate Mechanisms is extended to include submechanisms of gasoline surrogate compounds using a set of mechanism generation techniques. The mechanism yields very good predictions of species concentrations in premixed flames of n-heptane, isooctane, benzene, cyclohexane, olefins, oxygenates, and gasoline using a 23-component surrogate formulation. The 1,3-butadiene emission comes mainly from minor fuel fractions of olefins and cyclohexane. The benzene formation potential of gasoline components shows the following trends as functions of (i) chemical class: n-paraffins < isoparaffins < olefins < naphthalenes < alkylbenzenes < cycloparaffins < toluene; (ii) carbon number: n-butane < n-pentane < n-hexane; and (iii) branching: n-hexane < isohexane < 2,2,4-trimethylpentane < 2,2,3,3-tetramethylbutane. In contrast, fuel structure is not the main factor in determining acetylene formation. Therefore, matching the benzene formation potential of the surrogate fuel to that produced by the real fuel should have priority when selecting candidate surrogate components for combustion simulations.

Omega-(2-Naphthyloxy) amino alkanes as a novel class of anti-hyperglycemic and lipid lowering agents.

omega-(2-Naphthyloxy) amino alkanes, obtained as major by-product during course of synthesis of carbamate esters from omega-(2-naphthyloxy) alkyl halides and amines, showed significant anti-hyperglycemic and lipid lowering activities in various test models as a novel class of compounds. Compounds were tested in rat GLM, SLM, STZ, and STZ-S models at 100mg/kg dose. Of these compound 13 was found to be the most active which caused lowering of sugar by 33.6%, 31.0%, 28.5%, and 73.8% in GLM, SLM, STZ, STZ-S, and db/db mice models, respectively. It also significantly effected lowering of LDL in rat model and also in Hamster model without reducing HDL. Most of the compounds showing anti-diabetic and lipid lowering activity have shown promising PPAR-alpha/gamma/delta-activity. Compounds 6, 13, and 19 have shown very good PPAR-alpha/gamma/delta activity.

Strategies for the development of novel Taxol-like agents.

Taxol, the first microtubule stabilizer identified, is one of the most important new anticancer drugs to be brought to the clinic in the past 20 yr. The clinical success of TaxolTM led to the development of a second-generation taxane, docetaxel (Taxotere), and multiple third-generation taxane derivatives are under development. Non-taxane microtubule-stabilizers of diverse chemical structures, including the epothilones and discodermolide, show promising preclinical activities and several epothilones are progressing through clinical trials. One important advantage of the new stabilizers is their ability to circumvent drug resistance mechanisms. The clinical development of these new classes of agents suggests that microtubule stabilizers will continue to be important drugs for the treatment of cancer. This chapter provides a brief history of Taxol and the discovery and development status of other classes of microtubule stabilizers. Although all microtubule-stabilizers share similar mechanisms of action, interesting subtle differences among the stabilizers are being detected. This chapter also provides some strategies for identifying the differences among microtubule stabilizers that may help prioritize them for development and clinical use.

Virtual enantiomers as the solution of optical activity's deterministic offset problem.

Deterministic offsets have remained one of optical activity's most intractable problems. To the extent that the mechanisms by which they are produced do not depend on the chiroptical properties of the sample, they can be eliminated by the subtraction of measurements done on both enantiomers. We show that it is possible to create, by purely optical means, by the sole use of half-wave retarders, the optical antipode of a chiral molecule, to measure the chiroptical properties of the molecule and of its optically generated antipode, and to recover, by subtracting the measurements, the offset-free data of the enantiomer which is physically present. We moreover show that it is possible to do the measurements in a way that eliminates offsets that might occur through the influence of the differing chiroptical properties of the two antipodes. The procedure can be repeated, and by doing so, an almost arbitrarily high precision can be reached. The method is demonstrated by offset-free Raman optical activity back-scattering spectra measured in the so-called scattered circular polarization mode, one of optical activity's so far largely unsolved measurement problems. Such measurements can now be done with 2 mg of substance, in throw-away capillary cells, and on compounds sealed in cylindrical vials.

Selective transport and accumulation of alkanes by Rhodococcus erythropolis S+14He.

Selective transport and accumulation of n-alkanes by Rhodococcus erythropolis S+14He was studied by growing cells on n-hexadecane, n-octadecane or the branched alkane pristane, and on mixtures of hydrocarbons. Ultrastructural analysis by transmission electron microscopy (TEM) revealed hydrocarbon inclusion bodies present in cells grown on the three alkanes, but not in cells grown on soluble media or exposed to nonmetabolized 2,2,4,4,6,8,8-heptamethylnonane (HMN). n-Hexadecane had the highest rates of accumulation within the cells and higher overall consumption rates relative to the other alkanes. These rates decreased when the molar concentration of n-hexadecane was decreased in hydrocarbon mixtures, but at the same time the accumulation of n-hexadecane in intracellular inclusions became increasingly selective. Sodium azide significantly inhibited the accumulation of n-hexadecane, consistent with an active transport mechanism for accumulation. These results indicate that R. erythropolis S+14He is able to selectively discriminate and preferentially transport n-hexadecane from mixtures of structurally similar alkanes into intracellular inclusions by an energy-driven transport system. This selective membrane transport of hydrocarbon isomers has potential application for separations, bioprocessing, and the development of novel biosensors.