Mammalian survival depends on ultrasensitive olfactory detection of volatile sulfur compounds, since these compounds can signal the presence of rancid food, O depleted atmospheres, and predators (through carnivore excretions). Skunks exploit this sensitivity with their noxious spray. In commerce, natural and liquefied gases are odorized with t-BuSH and EtSH, respectively, as warnings. The 100-million-fold difference in olfactory perception between structurally similar EtSH and EtOH has long puzzled those studying olfaction. Mammals detect thiols and other odorants using odorant receptors (ORs), members of the family of seven transmembrane G-protein-coupled receptors (GPCRs). Understanding the regulator cofactors and response of ORs is particularly challenging due to the lack of X-ray structural models. Here, we combine computational modeling and site-directed mutagenesis with saturation transfer difference (STD) NMR spectroscopy and measurements of the receptor response profiles. We find that human thiol receptor OR2T11 responds specifically to gas odorants t-BuSH and EtSH requiring ionic copper for its robust activation and that this role of copper is mimicked by ionic and nanoparticulate silver. While copper is both an essential nutrient for life and, in excess, a hallmark of various pathologies and neurodegenerative diseases, its involvement in human olfaction has not been previously demonstrated. When screened against a series of alcohols, thiols, sulfides, and metal-coordinating ligands, OR2T11 responds with enhancement by copper to the mouse semiochemical CHSCHSH and derivatives, to four-membered cyclic sulfide thietane and to one- to four-carbon straight- and branched-chain and five-carbon branched-chain thiols but not to longer chain thiols, suggesting compact receptor dimensions. Alcohols are unreactive.

In this paper, we report the application of the advanced distillation-curve (ADC) approach to the gas turbine fuels Jet-A, JP-8, and JP-5, in order to obtain information about the variability of these gas turbine fuels. The measurements of the ADC derived temperatures T k and T h provide volatility information as an approximation of the vapor–liquid equilibrium, VLE. The composition channel of the advanced distillation curve provides access to more detailed insight into the fluid behavior. Finally, we have shown how the composition channel allows the combination of thermochemical data with the temperature data of the distillation curve. The variability in distillation curves and calculated heat of combustion between jet fuels is significant. Understanding of this variability is critical information for a more effective and reliable thermophysical property modeling system.

Carbon dioxide Assisted Nebulization with a Bubble Dryer((R)) (CAN-BD) processing allows particles to be made in the 3-5 mum size range, which is desirable for lung delivery, without destroying biological activity. In response to the Grand Challenge in Global Health Initiative #3, we have been developing an inhalable needle-free live-attenuated measles virus vaccine for use in developing countries. Measles was chosen because it is the number one vaccine preventable killer of children worldwide. Powders were processed by CAN-BD, where a solution containing excipients and live-attenuated measles virus in water was mixed intimately with supercritical or near superctitical carbon dioxide to form an emulsion. The emulsion was expanded to atmospheric pressure through a flow restrictor. The resulting plume was dried by heated nitrogen and the powders collected on a filter at the bottom of the drying chamber. Powders were analyzed using varying techniques including X-ray diffraction, scanning electron microscopy, Andersen cascade impaction, differential scanning calorimetery, Karl Fischer titration, and viral plaque assay. CAN-BD has been used to produce powders of live-attenuated measles virus vaccine with characteristics desirable for lung delivery. The powders retain viral activity through forming and drying the microparticles by CAN-BD, and have passed the WHO stability test for 1 week at 37 degrees C. The powders have an amorphous character and a glass transition temperature of around 60 degrees C. Lyophilization, the present standard commercial method of processing measles vaccine makes solids with a water content of less than 1%. By substituting myo-inositol for sorbitol and using the CAN-BD drying technique the water content can be lowered to 0.5%. The most successful formulations to date have been based conceptually on the current lyophilized formulation, but with modifications to the type and amounts of sugar. Of current interest are formulations containing myo-inositol, as they retain high viral activity and have low initial water content.

The analysis of gas turbine fuels by 1 H and 13 C nuclear magnetic resonance (NMR) spectroscopy as applied to the composition-explicit advanced distillation curve method is reported. To demonstrate the general applicability for such fuels, eight independent fuel samples were characterized: one sample of JP-5, one sample of JP-8, and six samples of Jet-A. Distillate fractions were obtained for each fuel by use of the advanced distillation curve (ADC) method. These fractions were analyzed by 1 H and 13 C NMR, along with the undistilled residue (i.e., the undistilled liquid remaining in the kettle after 90 vol % had been distilled) and the neat fuel. NMR spectroscopy is useful for the analysis of complex hydrocarbon mixtures because it provides the mole fractions of various classes of hydrocarbons, such as aromatics and linear alkanes, without the need to calibrate. NMR spectroscopy also gives ready access to other average properties for the components of each fuel sample, such as the extent and type of alkane branching. For example, the abundance of branch points at the β position of aliphatic chains changes little for the various distillate fractions; however, branching on the interior of the aliphatic chains approximately doubles over the course of the distillation. For the heavier fractions of the fuel, interior branching becomes as important as branching at the β and γ positions. Such information is useful for the development of realistic fuel surrogates required for reliable thermophysical models. Finally, we compare the results obtained by NMR spectroscopy to previously reported GC−MS and GC-FID analyses of the same fuel samples. ■ INTRODUCTIONThe distillation curve of a complex mixture provides a great deal of information about the mixture's properties; indeed it is one of the few volatility measurements that can be used for complex fluids. 1−4 Moreover, when measured properly, it is useful for thermodynamic modeling and for the development of surrogate mixtures. 5−7 A recent approach to distillation, known as the composition-explicit advanced distillation curve (ADC) method, has proven to be especially useful for the characterization of complex mixtures such as fuels. 8−17 The ADC method offers several improvements over earlier distillation methods (such as ASTM D-86); 8−14 one of the most valuable improvements is that it provides detailed information about the composition of each distillate fraction. This method uses a specially designed adapter that allows discrete distillate fractions to be sampled with a syringe. The samples can then be submitted to any desired quantitative or qualitative analysis methods.The distillate fractions from the ADC method typically have been analyzed by gas chromatography with flame ionization detection (GC-FID) or mass spectral detection (GC−MS). GC-FID is useful for the quantitative analysis of fuels because, for hydrocarbons, the detector response is (to a good approximation) proportional to the number of moles of carbon. 18 However, by itself, GC-FID provides very little ...