Analysis of position of trial sequence and type of diluent on the detection threshold for phenyl ethyl alcohol using a single staircase method.

Although detection thresholds for odors are commonly measured in academic and medical settings, the influences of procedural factors on threshold values are poorly understood. The present study evaluated the influences of (i) trial sequence position and (ii) diluent type on the threshold value for the rose-like odorant phenyl ethyl alcohol. In Exp. 1, detection thresholds were measured in 24 subjects on two occasions in which different diluents were used in the concentration series, propylene glycol and light mineral oil. The thresholds were estimated using a 7-reversal initially ascending single-staircase procedure. Threshold values were significantly influenced by the type of diluent (lower for mineral oil) and trial sequence (lower for later threshold reversals). In Exp. 2, 24 subjects were administered a staircase threshold test which continued through 15 staircase reversals. Continued testing resulted in a significant lowering of the threshold measure. These findings demonstrate the importance of both diluent and test length on detection threshold values measured by a single staircase procedure and emphasize the need for standardization of procedures for threshold testing.

Odor as an aid to chemical safety: odor thresholds compared with threshold limit values and volatilities for 214 industrial chemicals in air and water dilution.

The body of information in this paper is directed to specialists in industrial health and safety, and air and water pollution, who need quantitative data on the odor thresholds of potentially hazardous chemical vapors and gases. The literature, largely unorganized, has been reviewed for 214 compounds and condensed into tables based on consistent units. Data on the volatility, solubility, ionization and water-air distribution ratio at 25 degrees C are included. From the currently recommended threshold limit value (TLV), a safe dilution factor and an odor safety factor are calculated for each compound. The equivalent data are presented for both air and water dilutions of the chemicals. Available data are summarized on the variability of odor sensitivities in the population, and the increased odor concentrations that are required to elicit responses from persons whose attention is distracted, or who are sleeping. This information is reduced to calibration charts that may be used to estimate the relative detectability, warning potential and rousing capacity of the odorous vapors. Each compound has been assigned a letter classification, from A to E, to indicate the margin of safety, if any, that may be afforded by the odor of the compound as a warning that its threshold limit value is being exceeded.

Practical test kits for quantitatively evaluating the sense of smell.

A set of polypropylene squeeze-bottles, containing serial dilutions of pyridine in mineral oil, are used to deliver puffs of accurately odorized air to the nose. The patient's olfactory threshold can be quantitatively measured in a few minutes, and placed in the normal, hyposmic or hyperosmic range of sensitivity.

The pyridine scale for clinical measurement of olfactory threshold: a quantitative reevaluation.

Serial dilutions of pyridine in water are employed for measuring the olfactory detection thresholds of patients. Experimental precautions are described that improve the precision and accuracy of the method. Existing data on the sensitivities of hyposmic patients are confirmed, but the sensitivities of normal subjects and of hyperosmic patients are believed to have been substantially overestimated in some earlier publications. Routine clinical applications of the revised pyridine odor threshold test are discussed. In the author's experience, the average cystic fibrosis patient is slightly hyposmic, and some cases of pituitary tumor are accompanied by a 100,000-fold hyperosmia.

Ant alarm pheromone activity: correlation with molecular shape by scanning computer.

The ant Iridomyrmex pruinosus utilizes 2-heptanone as an alarm pheromone. The activities of 49 ketones and 35 nonketones as alarm pheromones for this species were determined. The molecular shapes of these compounds were assessed by submitting silhouette photographs of their molecular models to a pattern recognition machine. A highly significant correlation exists between molecular shape and alarm activity.