Influence Of Ultraviolet Light Research Articles

Hydrolytic De-amination of Amino-Acids

Virtanen and Erkama1 discovered recently in B. fluorescens liquefaciens an enzyme which causes hydrolysis of aspartic acid into malic acid and ammonia. This, however, is not the first example of hydrolytic de-amination of amino-acids. In a series of papers2, we have been able to show that in aqueous solution, amino-acids are hydrolysed under the influence of ultra-violet light to give the corresponding hydroxy-acids: R.CH(NH2).COOH→R.CH(OH).COOH. Here again, a certain resemblance exists between enzymatic and photochemical processes.

Photochemical Interaction between Ketones and Secondary Alcohols

IT has been observed by various authors1 and recently confirmed by an extensive investigation in our laboratory, that under the influence of ultraviolet light, secondary alcohols and ketones undergo a process of mutual oxidation and reduction. This can consist of a complete hydrogen exchange, or of the formation of pinacols,

286. The chain theory of the oxidation of phosphorus vapour. Part I. Comparison of the effect of hydrogen, deuterium, and helium on the lower explosion limit of phosphorus–oxygen mixtures. Part II. Displacement of the lower limit by ultra-violet light. Part III. Influence of ultra-violet light on the upper limit. Part IV. The stable oxidation reaction below the lower limit. Part

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The Action of Chlorine on p-Toluenearsonic Acid under the Influence of Ultraviolet Light and its Chlorination with Hypochlorous Acid

The Action of Chlorine on p-Toluenearsonic Acid under the Influence of Ultraviolet Light and its Chlorination with Hypochlorous Acid

Influence of Ultraviolet Light on the Glucose Tolerance of Rabbits

Influence of Ultraviolet Light on the Glucose Tolerance of Rabbits

Societies and Academies

Societies and Academies

Influence of Ultraviolet Light, Solar Irradiation and Cod-Liver Oil on Production, Fertility and Incubation of Eggs.

During the summers of 1926 and 1927 several sets of experiments were conducted in which eggs (from the same flock of white leghorns) were incubated under normal and under abnormal conditions. In all instances eggs were arranged in such a manner that some groups did not receive irradiation from a quartz-mercury are whereas other groups were irradiated for 10, 15 or 30 minutes a day, respectively. In general, these experiments showed that the daily average loss of weight for each egg when normally incubated amounted to 0.35 gm. Under abnormal incubation (with excessive moisture in the incubator) the loss of weight when the eggs were not irradiated was about 0.20 gm. With normal incubation, irradiation with ultraviolet light shortened the period of incubation 24 to 48 hours in about 20% of the eggs. The percentage hatch of normally incubated irradiated and nonirradiated eggs was practically the same. With abnormal incubation, ultraviolet irradiation increased the daily loss of weight and, with 30 minutes of ...

EXPERIMENTAL OBSERVATIONS ON IRRADIATED, NORMAL, AND PARTIALLY PARATHYROIDECTOMIZED RABBITS

The experiments described in the three papers of this series were undertaken to determine if possible the significance of the parathyroid hypertrophy that has repeatedly been found in rabbits after exposure to ultra-violet light. The fact that the hypertrophy was not accompanied by a corresponding increase in blood calcium led us to infer that the upper level of blood calcium concentration is governed by factors independent of parathyroid control, and that the gland hypertrophy under the influence of ultra-violet light might represent a potential functional capacity, or increased factor of safety, to protect the calcium level under conditions of stress or emergency. Partial parathyroidectomy in irradiated rabbits, compared with the same operation in normal controls, resulted in a similar immediate drop in blood calcium; but a more rapid restoration of the calcium level in the irradiated rabbits indicated a more prompt and active response to the emergency on the part of the remaining glands. In the second group of experiments no significant differences were found in the reactions of irradiated, normal, or partially parathyroidectomized rabbits to injections of calcium chloride or of disodium hydrogen phosphate. All three groups of rabbits rapidly eliminated the excess calcium from the blood. Their reactions to large doses of sodium phosphate, given subcutaneously, appeared to be related to phosphate elimination or retention in the individual animals. Those in each group which had phosphate retention in the blood died in acute tetany. So also in the fasting experiments, reported in this paper, no distinctions could be drawn between normal, irradiated, and partially parathyroidectomized rabbits on the basis of their calcium and phosphorus metabolism. Blood calcium was reduced in a similar manner in all three groups of rabbits, and wide individual variations in serum phosphorus levels preclude significant deductions. But the irradiated rabbits suffered disproportionate losses of weight during the fasting period and four of five of them died during the course of the experiment. The deaths of these rabbits are attributed to this more rapid consumption of their own tissues and possibly also to suprarenal injury caused both by fasting and by exposure to ultra-violet light.

THE INFLUENCE OF ULTRA-VIOLET LIGHT UPON THE GROWTH OF ANIMALS

The Influence of Ultra-Violet Light upon the Growth of Animals Kozo Suzuki, Kozo Suzuki Imperial Zootechnical Experiment Station, Chiba, Japan Search for other works by this author on: Oxford Academic Google Scholar Tadashi Hatano Tadashi Hatano Imperial Zootechnical Experiment Station, Chiba, Japan Search for other works by this author on: Oxford Academic Google Scholar Bulletin of the Agricultural Chemical Society of Japan, Volume 3, Issue 1, 1 January 1927, Pages 14–16, https://doi.org/10.1080/03758397.1927.10856808 Published: 01 January 1927 Article history Published: 01 January 1927 Received: 10 January 1927

The Influence of Ultraviolet Light Upon Blood Platelets in Young Rabbits.

Summary(1) Exposure to the mercury vapor quartz lamp has produced, within less than a week, a distinct platelet increase, in 6 normal young rabbits.(2) This increase varied from 40 to 100 per cent of the original normal, but always amounted to at least twice that of the normal variation in the animal. The platelet count returned to normal rather rapidly after having reached its maximum.(3) The red cells, at first decreased, began to rise at about the time of the platelet peak, returned to normal within 6 days, reached a million above normal in 2 weeks and in 2 cases maintained this level for 3 weeks after cessation of radiation.

Einstein's Photoelectric Equation and Contact Electromotive Force

Einstein's photoelectric equation for the maximum energy of emission of a negative electron under the influence of ultra-violet light, namely, 1/2mv^2 = Ve = hv - p cannot in my judgment be looked upon at present as resting upon any sort of a satisfactory theoretical foundation.

XIII. On acquired radio-activity

1. About forty years ago I sealed in a vacuum tube a yellow diamond cut as a brilliant. This diamond was chosen because it phosphoresced in the dark after exposure to bright sunshine,—it also phosphoresced slightly under the influence of ultra-violet light. In the vacuum tube, as the anti-cathode, it emitted a brilliant yellowish white light giving almost as much light as a candle. It was often exhibited to illustrate the glow of a diamond under the influence of cathode rays in vacuo ; scarcely a week passed without the vacuum tube containing the diamond being exhibited to friends. It was by far the most attractive tube in my collection. After forty years of hard work the diamond has become much dis-coloured. It was of interest to see if the repeated bombardment, as the anti-cathode, in the vacuum tube had conferred radio-activity on the diamond. Accordingly I opened the tube, quickly removed the diamond, and in the dark put it on a sensitive film, a thin sheet of black paper intervening. Over the diamond was placed a pad of cotton-wool and a weight, to prevent the stone from shifting its position. After nine days’ contact the film was developed. An exceedingly slight action could, with difficulty, be detected, showing that the off and on action for forty years had conferred practically no radio-activity on the diamond. 2. A sensitive electroscope was now made, with sulphur insulation. The fall of the leaf was observed with a small telescope having a photographed scale. The normal fall due to natural leakage was 5° in 165 seconds. A piece of a thoria gas mantle caused a fall of 5° in two seconds, and radio-active diamonds caused a fall in from two or three seconds to a fraction of a second. Tested in this instrument I found this special diamond to be entirely devoid of action.

Concerning the Influence of ultraviolet Light on the Circulation in Man1

Skandinavisches Archiv Für PhysiologieVolume 30, Issue 3 p. 73-96 Free Access Concerning the Influence of ultraviolet Light on the Circulation in Man† J. Lindhard, J. Lindhard Laboratory of the Finsen-InstitutSearch for more papers by this author J. Lindhard, J. Lindhard Laboratory of the Finsen-InstitutSearch for more papers by this author First published: September 1913 https://doi.org/10.1111/j.1748-1716.1913.tb00666.xCitations: 9 † Der Redaktion am 13. Februar 1913 zugegangen. AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat Citing Literature Volume30, Issue3September 1913Pages 73-96 RelatedInformation

The photo-electric fatigue of Zinc

Hertz’s observation that ultra-violet light can facilitate the passage of an electric spark led to the discovery of other photo-electric actions. In the earliest experiments on the photo-electric effect of metals it was noticed that the action was diminished by exposure to light. Thus Hallwachs, who found that a metal becomes positively electrified under the influence of ultra-violet light, states that “old surfaces no longer show the phenomenon. The radiation itself lowers the potential to which the plates can be electrified, so that with any succeeding experiment made with the same surface the potential obtained is lower, while the rise to it takes place more rapidly, and the decrease is greater than when for the same interval of time between the experiments the plate was not illuminated.” This diminution of the photo-electric action is spoken of as the "fatigue" of metals under the influence of light. It has received attention from many physicists, of whom Buisson and Ladenburg may be specially referred to.