Ethanol threshold

Vasopressin is a peptide hormone produced by the hypothalamus and secreted by the posterior pituitary in response to stimulation. Normal stimuli for vasopressin release are hyperosmolarity and hypovolemia, with thresholds for secretion of greater than 280 mOsm/kg and greater than 20% plasma volume depletion. A number of other stimuli, such as pain, nausea, epinephrine, and numerous drugs, induce release of vasopressin. Vasopressin release is inhibited by volume expansion, ethanol, and norepinephrine. The physiological effect of vasopressin is to promote free water clearence by altering the permeability of the renal collecting duct to water. In addition, it has a direct vasoconstrictor effect. Consequently, vasopressin results in water retention and volume restoration. In patients with septic shock, vasopressin is appropriately secreted in response to hypovolemia and to elevated serum osmolarity (R14). 

Determine (a) whether the following chemicals are covered under the PSM regulation and (b) their threshold quantities ammonia (anhydrous), hydrogen selenide, formaldehyde, methane, and ethanol. 

The specific compounds that are responsible for the "pea" flavor have not been identified. Bengtsson and Bosund (52) suggested that acetaldehyde, hexanal and ethanol were important, while Murray et al. (53) isolated three methoxypyrazines that have very low taste or recognition thresholds and might, therefore, be of major significance in pea flavor. 

Ethylene and D2O were formed only above a threshold exposure of the surface to ethanol. Figure 27 shows that acetaldehyde was first formed this was the result of the reactions... 

For some agents for example valproic acid and ethanol, a threshold concentration must be reached before teratogenicity is induced and the effect is therefore related to the maximum plasma concentration For others such as retinoids and cyclophos-... 

Table 10.1 gives a summary of the main by-products of fermentation by yeasts and other microbiological activities which can be identified in distilled spirits from different raw materials, like fruits, wine, grain, sugar cane, or other carbohydrate-containing plants. Since the sensory relevance of a flavour compound is related to its odour thresholds and odour quality. Table 10.1 presents also odour qualities and a review of threshold values of the fermentation by-products in ethanol solutions [9-10] and/or water [11-14] (Christoph and Bauer-Christoph 2006, unpublished results). 

Table 10.1 Odour quality, odour threshold value in water and/or ethanol solution, and concentration range of single volatile compounds in distilled spirits produced during alcoholic fermentation from carbohydrates by yeasts and other microorganisms ...

Compound Flavour quality Threshold (mgL water) Threshold (mgT ethanol solution) Typical concentration [mgL (40% v/v)] ... 

The odour thresholds given in Table 11.1 should be interpreted with caution. They differ according to the matrix in which they were determined (air, water, water-ethanol model, real wine), the sensitivity of the judges, the methodology... 

Typical results are shown in Fig. 44. The spectral threshold of the proper photoconductivity and the photo-emf of PAC is situated at 520 nm. The spectral response for the photo emf of PAC itself is shown by curve 1. After PAC has been immersed in an ethanol solution of methylene blue and dried its spectral response is represented by curves 2 and 2. The photo-response appears in the range of the absorption maximum of the dye at 680 nm characteristic of the monomolecular form in the dilute initial solution (curve 3). The observed enhancement of the second maximum at 620 nm in comparison to the solution spectrum is obviously connected with the presence of dye dimers. The shift of the maximum photoresponse to the longer wavelength by 15 nm relatively to the solution is usually the case for the adsorbed state. The sign of the charge carriers both in the proper and sensitized spectra ranges is positive. As seen in Fig. 44 the adsorption of the dye also markedly changes the proper photosensitivity of the PAC. When the monomolecular form of the adsorbed dye dominates, the... 

Asbestos dust in air can be trapped with an impinger dust-sampling apparatus using 25% aq ethanol as the collecting medium (Ref 4). The safe threshold value for asbestos dust exposure is considered 5 million particles per cubic foot... 

In cyclohexane no photoionization occurs after excitation of the La state and in ethanol the ionization threshold is at 256 nm [5] which is not reached even with the blue wing of our 270 nm excitation pulse with a width of 3.3 nm. To investigate the ultrafast photoionization we also investigate the ultrafast dynamics of indole dissolved in water. 

Figure 4 presents data on the cofermentation of glucose and xylose. The production of ethanol still appeared to be at the expense of glucose consumption. Note that systems E and F did not show significant differences whereas the amount of ethanol in system D was roughly 25% higher. This could imply that a threshold cell concentration is necessary. 

From these estimations of relative KP/L one can say that ethyl acetate would be the best choice in terms of the tendency to migrate into the beverage. Other considerations such as taste and odor thresholds may favor ethanol. 

The threshold level of a substance can be decreased by the presence of less sensori-cally active substances. In a mixture of ethanol, ethylacetate, ethyleneglycol mono-ethylether and toluene, the odor threshold level of ethyl acetate was reduced to half and in the case of cookies a factor of 5 decrease was observed. A reason for this finding may be the adsorption process taking place in the solid food. Compared to the solution processes in the complete food, the influence of other components on the ethyl acetate partition coefficient during a simple adsorption on the surface is likely to be larger. The repulsion of ethyl acetate from the surface increases its partial pressure over the food. 

Correct answer = D. Barbiturates and ethanol are a potentially lethal combination. Phenobarbital is unable to alter the pain threshold. 

---