Variations in IC50 Values with Purity of Mushroom Tyrosinase

The effects of various inhibitors on crude, commercial and partially purified commercial mushroom tyrosinase were examined by comparing IC₅₀ values. Kojic acid, salicylhydroxamic acid, tropolone, methimazole, and ammonium tetrathiomolybdate had relatively similar IC₅₀ values for the crude, commercial and partially purified enzyme. 4-Hexylresorcinol seemed to have a somewhat higher IC₅₀ value using crude extracts, compared to commercial or purified tyrosinase. Some inhibitors (NaCl, esculetin, biphenol, phloridzin) showed variations in IC₅₀ values between the enzyme samples. In contrast, hydroquinone, lysozyme, Zn²⁺, and anisaldehyde showed little or no inhibition in concentration ranges reported to be effective inhibitors. Organic solvents (DMSO and ethanol) had IC₅₀ values that were similar for some of the tyrosinase samples. Depending of the source of tyrosinase and choice of inhibitor, variations in IC₅₀ values were observed.     

Recipient-provider agreement on enacted support, perceived support, and provider personality.

This study examined agreement between recipients and providers about social support and personality. One hundred daughter caregivers of a parent with Alzheimer's disease and each caregiver's most important support provider independently reported supportive behaviors provided to caregivers, the perceived supportiveness of the provider, and providers' personality traits. For all indices, agreement was higher for enacted support than for perceived support and personality, which were similar to each other for some, but not all, indices of agreement. These findings support the validity of measures of enacted and perceived support. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

A test of the need gratification theory of job satisfaction.

Tested 2 hypotheses of M. Wolf's (see record 1970-05767-001) need gratification theory of job satisfaction-dissatisfaction, which emphasizes the moderating influence of psychological needs on the relationship between job elements and satisfaction. The needs of a stratified random sample of 75 nonacademic college employees were assessed by projective methods (e.g., the TAT). Neither of the original hypotheses was supported. It is suggested that need gratification theory be expanded to include situation variables. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Woman as mediatrix: women as writers on science and technology inthe eighteenth and nineteenth centuries

It is argued that although the writing on science and technology produced by women in the eighteenth and nineteenth centuries has usually been considered peripheral to scientific and technological advancement, the history of the mediatrix, or woman mediator, reveals that women writers carried out essential tasks. History suggests that women assumed the role of mediatrix much more frequently than they assumed other roles, largely because that role allowed women to contribute to science and technology without seriously violating gender norms. The careers and writing of four women mediators are described, showing that mediation is an unrecognized but crucially important aspect of the intellectual activity of science and that mediative writing often clarifies, rather than debases, scientific knowledge. The history of women mediators also suggests that intermediaries are essential for the functioning of the interlocking and overlapping groups and institutions that constitute science and technology and that it might be beneficial to restructure organizations so that the role of mediator is clearly defined and valued