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D Ertel

Publications and source records attributed to D Ertel.

5 recordsLinked to original sources

Luminol luminescence induced by oxidants in antioxidant-deficient yeasts Saccharomyces cerevisiae.

Luminol chemiluminescence induced in the presence of yeast cells and yeast cell homogenates was significantly induced by exogenous oxidants (hydrogen peroxide and menadione). tert-Butyl hydroperoxide did not stimulate chemiluminescence by itself but augmented menadione-induced chemiluminescence. Comparison of yeast strains deficient in catalase, superoxide dismutase or glutathione showed that only glutathione-deficient strains showed elevated chemiluminescence in this system. These results support the idea that more reactive species than hydrogen peroxide and superoxide are critical in the induction of luminol chemiluminescence.

Acatalasia↗

Simple determination of peroxyl radical-trapping capacity.

A simple spectrophotometric method of determination of peroxyl radical-trapping capacity (PRTC) of body fluids and food products is proposed. In this method, decomposition of 2,2'-azobis(2-amidopropane) hydrochloride (ABAP) is the source of peroxyl and alkoxyl radicals which oxidize 2,2'-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) to a green cation radical. Antioxidant present in a sample inhibit the reaction; the induction time of the reaction is proposed as a parameter enabling determination of antioxidant content. Standard assay conditions are: 20 mM ABAP and 150 microM ABTS in 0.1 M phosphate buffer, pH 7.0, at 37 degrees C; absorbance is monitored at 414 nm. A 10-min assay allows for determination of the induction time of appropriately diluted sample. As examples of application of this method, PRTC values of several types of beverages are reported.

Alcoholic Beverages↗

Effect of hyperthermia and lipid peroxidation on the erythrocyte membrane structure.

The hyperthermic exposure (39-49 degrees C) of human erythrocyte membranes augmented their lipid peroxidation stimulated by 0.1 mM FeCl3 + 1.5 mM ascorbate while having no significant influence on the non-stimulated lipid peroxidation. No effect of hyperthermia and lipid peroxidation on the post-exposure fluidity of the erythrocyte membrane lipids was found by the fluorescence anisotropy of hexatriene and trimethylaminophenylhexatriene, and excimerization efficiency of pyrene. Exposure to iron/ascorbate increased the accessibility of membrane protein tryptophan residues to acrylamide as judged by fluorescence quenching. These results suggest a higher sensitivity of membrane protein organization than of membrane lipid fluidity to the effect of the system inducing lipid peroxidation.

Ascorbic Acid↗

Personality correlates of drug preference among college undergraduates.

Three groups of college drug users--those expressing a preference for marijuana, amphetamines, or barbiturates--reported on experiences resulting from their drugs, and these groups, together with a group of nondrug-users, completed the Omnibus Personality Inventory (OPI). On the OPI the nonusers appeared more conventional and conforming than each drug group. Those preferring marijuana were less anxious than any other group, but the most distinctive group was that preferring barbiturates, which appeared the least intellectually inclined and the most emotionally distressed. This group's personality dispositions also seemed generally concordant with the experiences they reported from the drug.

Adolescent↗

Turning negotiation into a corporate capability.

Every company today exists in a complex web of relationships formed, one at a time, through negotiation. Purchasing and outsourcing contracts are negotiated with vendors. Marketing arrangements are negotiated with distributors. Product development agreements are negotiated with joint-venture partners. Taken together, the thousands of negotiations a typical company engages in have an enormous effect on both its strategy and its bottom line. But few companies think systematically about their negotiating activities as a whole. Instead they take a situational view, perceiving each negotiation to be a separate event with its own goals, tactics, and measures of success. Coordinating them all seems an overwhelming and impracticable job. In reality, the author argues, it is neither. A number of companies are successfully building coordinated negotiation capabilities by applying four broad changes in practice and perspective. First, they've established a company-wide negotiation infrastructure to apply the knowledge gained from forging past agreements to improve future ones. Second, they've broadened the measures they use to evaluate negotiators' performance beyond matters of cost and price. Third, they draw a clear distinction between the elements of an individual deal and the nature of the ongoing relationship between the parties. Fourth, they make their negotiators feel comfortable walking away from a deal when it's not in the company's best interests. These changes aren't radical steps. But taken together, they will let companies establish closer, more creative relationships with suppliers, customers, and other partners.

Commerce↗