Determination of solvation descriptors for terpene hydrocarbons from chromatographic measurements

This article discusses the determination of solvation descriptors for terpene hydrocarbons from chromatographic measurements

Solvation Descriptors for Ferrocene, and the Estimation of Some Physicochemical and Biochemical Properties

Article on solvation descriptors for ferrocene, and the estimation of some physiochemical and biochemical properties

Determination of solvation descriptors for terpene hydrocarbons from chromatographic measurements

This article discusses the determination of solvation descriptors for terpene hydrocarbons from chromatographic measurements

Odorous and pungent attributes of mixed and unmixed odorants

In order to explore functional properties of the olfactory and common chemical senses as well as their relation to the total nasal sensation experienced, various concentrations of two pungent odorants were presented alone and in the presence of different backgrounds of the other irritant. Stimuli comprised formaldehyde (at 1.0, 3.5, 6.9, and 16.7 ppm), ammonia (at 210, 776, 1,172, and 1,716 ppm), and their 16 possible binary mixtures. Subjects were asked to estimate the total nasal perceived intensity, and then to assess the olfactory (odor) and common chemical (pungency) attributes of the evoked sensations. The results showed that stimulus-response functions for pungency are steeper than those for odor. Furthermore, odor was always hypoadditive in mixtures (i.e., mixtures were perceived as less intense than the sum of their components), whereas pungency was, mainly, additive, and even suggested hyperadditivity. Total perceived intensity of the stimuli, alone and in mixtures, followed the stimulus-response patterns for pungency, which, therefore, emerged as the dominating attribute used by subjects in scaling the explored range of concentrations. The relationship between total nasal perceived intensity of the mixtures and that of their components reflected hypoaddition, resembling the outcome for the odor attribute

Odorant-Dependent Generation of Nitric Oxide in Mammalian Olfactory Sensory Neurons

The gaseous signalling molecule nitric oxide (NO) is involved in various physiological processes including regulation of blood pressure, immunocytotoxicity and neurotransmission. In the mammalian olfactory bulb (OB), NO plays a role in the formation of olfactory memory evoked by pheromones as well as conventional odorants. While NO generated by the neuronal isoform of NO synthase (nNOS) regulates neurogenesis in the olfactory epithelium, NO has not been implicated in olfactory signal transduction. We now show the expression and function of the endothelial isoform of NO synthase (eNOS) in mature olfactory sensory neurons (OSNs) of adult mice. Using NO-sensitive micro electrodes, we show that stimulation liberates NO from isolated wild-type OSNs, but not from OSNs of eNOS deficient mice. Integrated electrophysiological recordings (electro-olfactograms or EOGs) from the olfactory epithelium of these mice show that NO plays a significant role in modulating adaptation. Evidence for the presence of eNOS in mature mammalian OSNs and its involvement in odorant adaptation implicates NO as an important new element involved in olfactory signal transduction. As a diffusible messenger, NO could also have additional functions related to cross adaptation, regeneration, and maintenance of MOE homeostasis

Using Human Panels for Subjective Evaluation of Emissions from Indoor Activities and Materials: Principles and State of Technology

This report addresses the topic of sensory evaluation of indoor air through the use of human subjects. It begins by discussing the chemical senses involved in such evaluation, specifically the senses of smell (olfaction) and chemical sensory irritation (common chemical sense, CCS, now called chemesthesis). An analysis of similarities and differences between these two sensory modalities regarding key measurements and issues follows. Later, the report discusses the quantification of sensory reactions to indoor pollutants, including aspects related to subjects, exposure techniques, sensory methodology, quality assurance, and data evaluation. An Appendix presents the results of a survey of opinion regarding a tentative protocol for sensory evaluation of emissions from indoor activities and materials, based on the responses of 16 out of the 25 indoor air researchers initially contacted to fill out the questionnaire

Percepción de Estímulos Químicos Irritantes Aislados y en Mezclas Binarias (Perception of Irritant Chemical Stimuli Singly and in Binary Mixtures).

Section I of this Thesis presents the stimulus-response (i.e., psychophysical) functions for the total nasal perceived intensity of two pungent odorants, formaldehyde and ammonia, presented either alone or mixed with varying concentrations of the other irritant. Stimuli comprised formaldehyde at 1.0, 3.5, 6.9, and 16.7 ppm; ammonia at 210, 776, 1,172, and 1,716 ppm; and their 16 binary mixtures. At low, medium, and high concentrations within the ranges selected, the total perceived intensity of the mixtures was, respectively, significantly lower than (hypoadditivity), equal to (simple additivity), and greater than (hyperadditivity) the sum of the intensities of its individual components. In Section II, subjects were again asked to rate the total nasal perceived intensity of the previous stimuli, but now they also rated the olfactory (i.e., odor) and the trigeminal (i.e., pungency or irritation) attributes of the evoked sensations. Psychophysical functions for pungency were steeper than those for odor. Furthermore, odor was always hypoadditive in mixtures, whereas pungency was, mainly, additive, and even reached hyperadditivity. Total nasal perceived intensity of the stimuli, singly and in mixtures, followed the stimulus-response patterns for pungency, which, therefore, emerged as the dominating attribute used by the subjects to rate the explored range of concentrations. In turn, the relationship between total nasal perceived intensity of the mixtures and the sum of the intensities of their components reflected hypoadditivity, resembling the outcome for the odor attribute