Four groups of female Dutch-belted rabbits (Oryctulagus cuniculus) were given methoxsalen (12 mg/kg) or placebo by oral intubation and 1 hr later were exposed to UVA for either 2 or 8 hr. This procedure was repeated 5 days each week for 18 mo. A fifth group received no drug and no UVA exposure. The skin of the animals given methoxsalen and UVA showed signs of acute and chronic phototoxicity. Multiple peripheral blood parameters of hepatic, renal and hematologic function were normal and were not different between groups. Complete ophthalmoscopic examinations were performed periodically. No cataracts were seen in any of the animals. This data provides the perspective that in one species the daily dose of methoxsalen and UVA required to induce chronic cutaneous photosensitization is lower than the daily dose required to induce cataracts. It is inadvisable to interpret this data as suggesting that no risk exists for patients being treated with oral methoxsalen photochemotherapy. The experimental evidence supporting photosensitization as a cause of cataracts and implicating a role of lens DNA in this cataractogenesis is reviewed. Because methoxsalen-UVA alterations of lens DNA or protein could lead to delayed onset of cataracts, and because of the serious nature and potential preventability of phototoxic lens opacification, appropriate protective eye wear is recommended for all patients receiving oral psoralen photochemotherapy.

Several proteins found in the adhesive system of the common blue mussel Mytilus edulis have chemical properties which may enable them to inhibit the flash rusting of steels. In this work, Mytilus edulis foot proteins (MAPs) 1, 3, and 5 were isolated and applied to a high strength low alloy steel in a number of buffer systems containing varying amounts of borate, acetate, and phosphate at pH 5.5-7.0. Treated steel samples were then monitored in an exposure chamber at 40 • C and 100% relative humidity for 7 days. The MAP treatments were also evaluated using electrochemical impedance spectroscopy (EIS). The effect of enzymatic crosslinking of the applied proteins using mushroom tyrosinase was also investigated. Steel samples treated with MAP-1 did not inhibit corrosion when the protein was dissolved in deionized water, and the effect of MAP-1 dissolved in buffers containing acetate was not significantly different from control samples. However, when dissolved in 0.05 M phosphate buffer solution at pH 5.5, MAP-3 and MAP-5 were capable of significantly increasing the time to corrosion and significantly reducing the mass loss of the steel coupons in the exposure chamber compared with controls when treated with enzyme. The performance of the crosslinked MAP-5 was similar to a commercial flash rust inhibitor applied at the same mass concentration as the protein, suggesting that MAP-5 and similar proteins or polymers may be capable of inhibiting corrosion. In the past two decades, mussel adhesive proteins (MAPs) from the common blue mussel Mytilus edulis (L) have been the subject of a few investigations into their potential use as corrosion inhibitors, with the hope being that the properties of these biomolecules could be replicated in new formulations of environmentally-friendly corrosion inhibitors. [1][2][3][4] MAPs have a number of unique properties, most of which rely to some extent on the presence of the catecholic amino acid L-3, 4 dihydroxyphenylalanine (DOPA). Like other catechols, DOPA can form strong complexes with many metals, particularly Fe(III).5 These metal-catechol complexes can form either in solution, or on a metal oxide surface.6 It has been shown that in some cases the formation of stable organometallic complexes on a metal surface can inhibit corrosion by preventing the dissolution of the oxide layer to which it is adsorbed.7 Previous investigations have indicated that DOPA-containing proteins are capable of inhibiting corrosion to various degrees on some metals. 1,[8][9][10][11][12][13] In addition to this, DOPA can participate in crosslinking reactions as a result of chemical or enzymatic oxidation. When oxidized, DOPA forms a quinone-intermediate, which can in turn react further with catechol groups or nucleophiles present elsewhere in the protein to form a crosslinked protein.14,15 Previous findings by Hansen et al. 16 demonstrated that enzymatic cross-linking of adsorbed MAP-1 protein resulted in thickening of the protein film, whereas others have reported a compression of the adsorbed prot...

Drawing on current psychological, philosophical, and rhetorical theories, a scheme is presented which will allow the classification, indexing, and retrieval of computerized.information using content-free cues. The system i s patterned after that of human information retrieval and with current software packages can be completely 'I'hc primary assumption of any classification theory is that, events, wncepts, referents, etc., can ttc classified according to some kind of scheme. The task of developing :t siiit.:iblc cliissification scheme is complicated by the in-process ixrture of things to be classified ( l ) , and by the variability in form and substance of the classification instmmeiit. A generalizable classification theory should be free from constraints of time, space, and cultural influcnce, and should grow from exigencies within knowledge demanding classification.Authorization for development of a classification scheme is gained through examination of the inherent characteristics of knowledge. A t least two questions arc cssential to development of a viable theory: ( I ) What do we know of knowledge classification? ( 2 ) How can this information be applied to classification theory? The prcsmt treat,ment is an attempt to find tenable answers to these t,wo questions. What Do We Know of Knowledge Classification?Since knowlcdgc is data already processed through the human organism, the structure of knowledge is af€ected by the structure of the human cognitive system through which it is conccptudized. Rules for knowledge classification, then, must come from rules generated by the human conceptual system as it is in the process of interacting with its environment.Fortunately, research findings converge at four points permitting the following axiomatic statements regarding a conceptual structure for knowledge:( 4 ) , Haygood and Bourne ( 5 ) , Bourne (6), Wilson and Arnold ( 7 ) , and others. Of consequence is the fa,ct that at least two axes continually appear. One axis, whose quan-298 American Documentation -October 1969

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