(a.) Of or pertaining to chemical action of light, or produced by it; as, the photochemical changes of the visual purple of the retina.
Example Sentences:
(1) These results suggest that photochemical modification of a single residue of aspartate (or asparagine) is largely, if not entirely, responsible for photoinactivation of the enzyme under these conditions.
(2) The probes were biotin treated by chemical modification of the DNA by the peraminating reagent or photochemically.
(3) All recombinants were found to be photochemically active, in that optical bleaching produced a temperature- and lipid chain-length-dependent mixture of species absorbing at 480 and 380 nm.
(4) We have investigated the relationship between rhodopsin photochemical function and the retinal rod outer segment (ROS) disk membrane lipid composition using flash photolysis techniques.
(5) Once training was complete, unilateral, bilateral or sham-infarction restricted to the region of the primary somatosensory cortex was produced by a non-invasive photochemical technique, which induces platelet-activated vascular occlusion combined with blood-brain barrier changes and subsequent cell death.
(6) Finally, the estimate of the photochemical activity of P-700, based upon the measured fluorescence quantum yield and upon the measured nonradiative losses of excitation energy, was done.
(7) The purpose of the present study was to develop a technique capable of detecting photochemical changes in the genetic material of human cells in tissue culture.
(8) The photochemical activities and fluorescence properties of cells, spheroplasts and spheroplast particles from the blue-green alga Phormidium luridum were compared.
(9) The photochemical action spectrum for the light reversal of inhibition showed a single maximum of effectiveness at about 420 nm.
(10) In the present study we examined the effect of systemic tocainide on sensory hypersensitivity in rats after spinal cord ischemia induced by a photochemical technique.
(11) Because there is no lower intensity threshold for photochemical reactions, it seems probable that the photobiological effects described in this paper occur in most newborns to some degree.
(12) The antithrombotic properties of Placenta Protein 4 (PP4) were investigated in laser or photochemically induced thrombus formation models in rats.
(13) The photochemical reactions were initiated by ultraviolet light of lambda greater than 300 mn, employing acetone as a photosensitizer.
(14) Photochemical alterations following ultraviolet irradiation of the alternating copolymer d(GT)n.d(CA)n were studied.
(15) Model experiments with two structurally different proteins (alcohol dehydrogenase and salmine) show that glycine, alanine, and tyrosine are by far more frequently involved in photochemically induced cross-link formations with DNA than is cysteine.
(16) Reaction centers reconstituted with other quinones also showed restored photochemical activity, although they exhibited changes in their low-temperature recombination kinetics and light-induced (g = 1.8) EPR signal is interpreted in terms of a magnetically coupled ubiquinone--Fe2+ acceptor complex.
(17) For this purpose photochemically induced dynamic nuclear polarization 1H nuclear magnetic resonance (CIDNP 1H NMR) spectroscopy and quenching of tryptophan and tyrosine fluorescence by acrylamide were applied to an apocytochrome c-sodium dodecyl sulfate (SDS) micellar system.
(18) The effect of photochemical fluorochromizing used in the method suggested consists in the following: after the exposure of sections to short-wave ultraviolet irradiation the preparations start to fluorescence intensively in the visible region with the long-wave the myocardium of mice, dogs and section materials showed that following photochemical fluorochroming the intensity of lumenescence of damaged cells of the myocardium increased markedly as compared with that of intact cells.
(19) KCN or iodine also blocked NO production by tissue, but had no effect upon photochemical NO release.
(20) The main limitation of phototherapy is that it is inefficient, a limitation that seems to be imposed by transport processes in the body and the optics of skin rather than by the photochemical reactions on which it depends.
Photochemistry
Definition:
(n.) The branch of chemistry which relates to the effect of light in producing chemical changes, as in photography.
Example Sentences:
(1) Photolysis of the photosystem I particles induces a progressive depletion of phylloquinone, however, photochemistry as assayed at room temperature by the photooxidation of P-700 is unaffected.
(2) Examples have been given for the three possibilities concerning photochemistry of nucleic acids and proteins.
(3) Studies of acrylamide quenching of tryptophan (Trp) fluorescence, photochemistry, and photoionization have been conducted.
(4) These results indicate that plastoquinone functions as the primary electron acceptor of Photosystem II and that beta-carotene does not play a direct role in the primary photochemistry but is required for the C-550 absorbance change.
(5) The photochemistry (Type I and II) of the phototoxic textile dye Disperse Blue (DB-35) and its purified components has been studied using electron spin resonance in conjunction with spin trapping technique and the direct detection of singlet oxygen (1O2) luminescence.
(6) The photochemistry of drugs can be useful (phototherapy) or harmful (phototoxicity).
(7) The photophysics and photochemistry of the 4'-diethylamino derivative of both 2-phenyl-benzothiazole and 2-(2'-hydroxyphenyl)benzothiazole have been studied by nanosecond and microsecond laser flash photolysis and picosecond emission spectroscopy.
(8) The HisM200----Leu RC, which has a heterodimer consisting of a bacteriochlorophyll and a bacteriopheophytin, is capable of the primary photochemistry observed in wild-type Rb.
(9) The photochemistry of benzanthrone (7H-benz[de]-anthracene-7-one) has been studied using electron paramagnetic resonance (EPR) in conjunction with the spin trapping technique and the direct detection of singlet molecular oxygen luminescence.
(10) The results are related to the photochemistry of thymidine and of bacteriophages containing incorporated 5-ethyluracil in place of thymine.
(11) The Hb photochemistry is a complex set of photoreactions leading to successive photoconversions of Hb forms: from oxy- to met- to deoxy- and, finally, to carboxy-form.
(12) The quenching action of dibromothymoquinone on fluorescence and on primary photochemistry was examined in chloroplasts at minus 196 degrees C. Both the initial (F0) and final (FM) levels of fluorescence as well as the fluorescence of variable yield (FV equals FM minus FO) were quenched at minus 196 degrees C to a degree which depended on the concentration of dibromothymoquinone added prior to freezing.
(13) These results were determined through nonlinear least squares regression and residual analyses, with some knowledge of the possible photochemistry of the cofactor by itself.
(14) The photochemistry of trace amounts of isobutene and oxides of nitrogen in an atmosphere of air was studied both in the presence and in the absence of small amounts of carbon monoxide.
(15) The basic law is: "No photobiology--no photochemistry".
(16) The photochemistry of the isolated Photosystem II reaction-centre core from pea and the green alga Scenedesmus was examined by e.s.r.
(17) This information is important not only for the understanding of the basic structure of vitamin A but also the photochemistry of vision.
(18) We have also attempted to do in situ fluorescence spectroscopy on isolated intact eye lenses, which has enabled us to follow the photochemistry and the status of the photoproduct of the oxidation of the trp residues of the crystallins of the lens.
(19) We have studied the photochemistry of the thymine-PABA and thymidine-PABA systems and report here the isolation and characterization of thymine-PABA and thymidine-PABA photoadducts.
(20) This indicates that the high irradiances available from the excimer laser cause the same DNA photochemistry as the lower-irradiance CW sources.