Cells from a region on the posterior margin of the developing avian limb bud (the polarizing region) can signal positional information to responding anterior cells. Polarizing activity may be assayed by disaggregation of the tissue into single cells, followed by reaggregation and grafting of cell pellet. This method enables treatments of the cells while in single-cell suspension. The effects of...

Several investigators have reported that white light will counteract the effects produced in lower organisms exposed to ultraviolet light. Whitaker (14) has observed that the inhibitory effects of ul traviolet on fucus eggs could be counteracted by white light. Kelner (6)-has demonstrated spectac ular recoveries of various micro-organisms in activated with ultraviolet. Blum and Matthews (3) hav...

OBJECTIVE To compare the conventional psoralen-ultraviolet A treatment with psoralen-ultraviolet B therapy in the treatment of psoriasis. METHODOLOGY We studied 50 patients of plaque type psoriasis who were selected to receive either conventional psoralen-ultraviolet A or psoralen-ultraviolet B treatment. RESULTS There was no significant difference between the two treatment groups in the nu...

1. A study has been made of the effect of ultraviolet irradiation on the conformational changes taking place in cooled solutions of thermally denatured acid-soluble calf-skin collagen. 2. The increase in negative rotation and viscosity at 15 degrees for irradiated and thermally denatured collagen solutions becomes less as the irradiation dose is increased. 3. The principal effect of ultraviolet...

The effect of ultraviolet-B (280 to 320 nm) irradiation on physiological activities of Anabaena flos-aquae and the water fern Azolla caroliniana has been studied under conditions where lethal effects of irradiation are absent. Nitrogenase activity, measured as acetylene reduction, specifically declined during irradiation with low levels of ultraviolet-B, whereas other physiological activities w...

Introduction. Azithromycin is among the broad-spectrum antibiotics that is widely available in various environmental systems and could have destructive effects on the ecosystem and human health due to its bacterial resistance. In this study, removal of azithromycin from wastewater using an advanced oxidation process of ultraviolet light with and without persulfate was investigated and effective...