scholarly journals The distillation of vitamin D

1930 ◽  
Vol 107 (748) ◽  
pp. 76-90 ◽  
Keyword(s):  
Vitamin D ◽  
Vacuum Distillation ◽  
Complex Mixture ◽  
Ultra Violet ◽  
Mercury Vapour ◽  
Silica Tube ◽  
Ethereal Solution ◽  
Mercury Vapour Lamp

The work described below has been done in an attempt to isolate vitamin D from the complex mixture formed by the ultra-violet irradiation of ergosterol. It is evident that vacuum distillation might be of use for this purpose, but, except for a brief statement by Windaus and Holtz (1927), we are unaware of previous work on the distillation of vitamin D. We have distilled various products obtained from ergosterol, and most frequently have used resinous products prepared as follows. A solution of ergosterol in ether was exposed to the unfiltered radiation from a mercury vapour lamp while flowing through a narrow silica tube at a rate such tat about 40 per cent. of the ergosterol was destroyed. Thy unchanged ergosterol was then removed by precipitation with digitonin as described in a previous paper (Webster and Bourdillon, 1928) and the ethereal solution of the products of radiation was evaporated in vacuo to a dry resin.

scholarly journals The coagulation of protein by sunlight

1922 ◽  
Vol 93 (651) ◽  
pp. 235-248 ◽  
Keyword(s):  
Temperature Coefficient ◽  
Tap Water ◽  
Wave Length ◽  
Ultra Violet ◽  
Protein Molecule ◽  
Mercury Vapour ◽  
Absorption Bands ◽  
Ultra Violet Light ◽  
Violet Light ◽  
Mercury Vapour Lamp

It was first shown by Dreyer and Hanssen (1) in 1917 that ultra-violet light produced a change in protein solutions which appeared to be similar to coagulation by heat. They exposed various solutions in quartz chambers to the light of a Bang lamp with iron and silver electrodes. Vitellin was found most easily coagulated, while globulin, albumin and fibrinogen showed a decreasing sensitivity to ultra-violet rays in the order mentioned. These investigators also discovered that acids markedly increase the rate of precipitation. Soret (2) had shown in 1883 that there are absorption bands in the extreme ultra-violet region of the spectrum of various proteins, e. g. , casein, ovalbumin, mucin and globulin. Tyrosine likewise has this band in the ultra-violet and Soret attributed to this constituent of the protein molecule its power of absorbing ultra-violet rays. In this connection Harris and Hoyt (3) carried out some interesting experiments on the protective power of various substances for paramœcium cultures exposed to ultra-violet radiations. They found that gelatin peptone, amino-benzoic acid, cystine, leucine and especially tyrosine possessed the power of detoxicating ultra-violet rays when placed as a thin layer of aqueous solution over paramœcium cultures under a quartz-mercury lamp. The toxicity of the radiations for paramœcia or protoplasm in general can be understood in the light of the discovery of Dreyer and Hanssen coupled with that of Soret. From a physico- chemical standpoint Bovie (4) has published a study of the coagulation of proteins by ultra-violet light. By exposing solutions of crystalline ovalbumin, both dialysed and containing electrolytes, to the light of a mercury-vapour lamp, he came to the conclusion that there were two reactions involved in the coagulation of ovalbumin by ultra-violet light. The first is a photochemical one with a low temperature coefficient,—denaturation; and the second is one with a higher temperature coefficient of two and is dependent upon the electrolytes present,—coagulation. While using solutions dialysed against tap water Bovie made the observation that the protein appeared to become sensitive to light of longer wave-length, for his control tubes in glass were slowly coagulated.

scholarly journals The photo-chemistry of potassium permanganate.-Part II. On the energetics of the photo-decomposition of potassium permanganate

1923 ◽  
Vol 103 (722) ◽  
pp. 366-382 ◽  
Keyword(s):  
Potassium Permanganate ◽  
Wave Length ◽  
Ultra Violet ◽  
Mercury Vapour ◽  
Interesting Contribution ◽  
Quartz Mercury ◽  
Mercury Vapour Lamp ◽  
The Subject ◽  
Photo Chemistry ◽  
Photo Decomposition

It has been demonstrated in a previous communication that potassium permanganate is decomposed on illumination by light from the quartz mercury-vapour lamp. It was, therefore, of interest to determine the wave-length of the chemically active light and to investigate if possible the validity of the Einstein law of photo-chemical equivalent which so far has been stated not to apply to substances in solution. A study was, therefore, made of the absorption spectrum of potassium permanganate, particularly with reference to the ultra-violet, since this region is the most lacking in qualitative data. The absorption in the visible regions of the spectrum has been studied by many authors, notably Formänek, and has recently been the subject of an interesting contribution by Hagenbach and percy, who have the subject of an interesting contribution by Hagenbach and percy, who have resolved it into a simple spectral series.

scholarly journals Certain pathological effects of ultra-violet radiation on mosquito larvæ and pupæ

1932 ◽  
Vol 112 (774) ◽  
pp. 27-38 ◽  
Keyword(s):  
Ovarian Function ◽  
Wave Length ◽  
Ultra Violet ◽  
Mercury Vapour ◽  
Mosquito Larvae ◽  
Wave Band ◽  
Ultra Violet Radiation ◽  
Quartz Mercury ◽  
Mercury Vapour Lamp ◽  
Violet Radiation

In the course of recent work on the possible effect the ultra-violet wave-band may have on the activation of ovarian function in female mosquitoes, it became apparent that mosquito larvae are highly susceptible to a remarkable form of injury by radiations from the unshielded mercury-arc generated by the ordinary Cooper-Hewitt vacuum type of quartz mercury-vapour lamp. This effect upon the larvae has been studied, and an attempt was made (1) to determine the wave-length of the radiations responsible for the injury by means of screens interposed between the lamp and the larvae; and (2) to ascertain the physiological and histological nature of the injury.

Light Therapy in Mental Hospitals

1929 ◽  
Vol 75 (310) ◽  
pp. 410-419 ◽  
Author(s):  
H. Dove Cormac
Keyword(s):  
Ultra Violet ◽  
Light Therapy ◽  
Electric Arc ◽  
Mercury Vapour ◽  
The Sun ◽  
The Past ◽  
Mental Hospitals ◽  
Quartz Mercury ◽  
Mercury Vapour Lamp ◽  
Carbon Arc

The value of sunlight in the maintenance of health has been recognized from early ages, and history records sun-worship by many nations in the past as well as at the present time. In Europe records exist of the use of the light of the sun for medical and surgical purposes since before the Christian era, but it was only towards the end of the last century that its possibilities began to be studied and the value of the electric arc lamp as a substitute recognized. In 1893 Finsen demonstrated the value of sunlight and electric arc radiation in the treatment of lupus, and at the beginning of the present century Bernhard of Samaden treated wounds and tuberculous lesions with sunlight. In 1903 Rollier opened his first clinic at Leysin, where he obtained excellent results in the treatment of tuberculosis, especially of the surgical type, by insolation in the brilliant Alpine sunshine. In 1908 Gauvain introduced heliotherapy at Hayling Island and at Alton. Nagelschmidt used the air-cooled quartz mercury vapour lamp for general irradiation in the same year, and in 1913 Reyn commenced the use of the carbon arc for the same purpose. The value of ultra-violet rays in the cure of rickets was not recognized till demonstrated by Huldschinsky in 1918, though Palm (1), as early as 1890, urged that deficiency of sunshine was a cause of the condition.

scholarly journals Effects of ultra-violet radiation upon involuntary muscle, and the supposed physiological interference of visible rays

1926 ◽  
Vol 99 (696) ◽  
pp. 221-229 ◽  
Keyword(s):  
Ultra Violet ◽  
The Other ◽  
Pigment Cells ◽  
Mercury Vapour ◽  
Ultra Violet Radiation ◽  
The Earth ◽  
Involuntary Muscle ◽  
Mercury Vapour Lamp ◽  
Violet Radiation ◽  
Exciting Effect

It was shown by Adler (1) that involuntary muscle is excited and its tone increased by radiation with ultra-violet rays. The excised frog’s stomach, the bladder and the uterus of the rabbit, and that of the guinea-pig, were suspended by him, each in a suitable salt solution, and excited by the mercury vapour lamp. With a glass screen interposed no result was obtained, the visible and longer ultra-violet rays, e. g ., those longer than about 3200 A. U., having no exciting effect. There may be recalled the old observation of Lambert (1760) that the excised iris of fish and frogs reacts to light by contraction; the visible rays in this case act through the pigment which absorbs them (Steinach, Hertel). Contraction of the pigment-free ventral band of the earth-worm can be produced by ultra-violet, but not by visible rays. On the other hand, visible rays excite the pigmented ventral band of Sipunculus nucleus (Hertel, 2). Probably the nerve plexus is excited by the conversion of visible rays into heat in the pigment cells which absorb these rays.

scholarly journals A photoelectric spectrophotometer using dual electrostatic compensation

1934 ◽  
Vol 144 (851) ◽  
pp. 118-128 ◽  
Keyword(s):  
Light Intensity ◽  
Light Source ◽  
Wave Length ◽  
Ultra Violet ◽  
Mercury Vapour ◽  
Extinction Coefficients ◽  
Mercury Vapour Lamp ◽  
Terminal Voltage ◽  
Mechanical Devices ◽  
Approximate Result

The photometer here described is suitable for the purpose of measuring extinction coefficients of substances in solution, more particularly in the ultra-violet region. The method employed is a purely electrical one, and does not involve the use of any mechanical devices (sectors or wedges, etc.) for the quantitative variation of light intensity. Errors due to fluctuations of the light source are eliminated by the use of two photoelectric cells, while the simultaneous electrostatic compensation of both cells does away with the necessity of measuring or controlling times of exposure. The actual observations are of (i) a resistance plugged into a resistance box, and (ii) an electrometer defection. The former gives tbs approximate result and the latter the correction to be applied. II. Description of apparatus and method . The source of light is a vertical mercury vapour lamp, running at about 3½ amps, and about 100 volts terminal voltage. The light from this source is condensed upon the slit of a double quarts monochromator by a suitable cylindrical quarts lens with its axis vertical. means of the double quarts monochromator, which has auxiliary dispersing prisms rotated by means of wave-length drums, any desired wave-length emitted by the source can be selected and allowed to enter the photoelectric photometer.

X.—A New Method of Starting Mercury Vapour Apparatus

1914 ◽  
Vol 33 ◽  
pp. 117-123
Author(s):  
John S. Anderson ◽  
George B. Burnside
Keyword(s):  
Ultra Violet ◽  
Electrical Energy ◽  
Electrical Current ◽  
Public Works ◽  
Mercury Vapour ◽  
Great Success ◽  
Reference Spectrum ◽  
Ultra Violet Radiation ◽  
Mercury Vapour Lamp ◽  
Violet Radiation

The mercury vapour lamp, although very economical in its use of electrical energy, is not employed very extensively at the present day for illuminating purposes, chiefly because the light it emits is not white, but of a greenish hue. Many attempts have been made to produce the deficient red radiation, but these have so far not met with any great success. The lamp, however, is useful as an illuminant where the colour of the light is of no great importance, such as in public works, etc. Further, it is very much used, in the form of rectifiers, for changing alternating to direct electrical current. During the past few years there has been an increasing demand for lamps which are rich in ultra-violet radiation, which is useful for photographic and medical purposes, as, for example, the sterilisation of water, milk, etc. This requirement is met by the mercury vapour lamp, for the ultra-violet spectrum of mercury is particularly intense; lamps used for this purpose must be made of quartz, since ordinary glass absorbs ultra-violet radiation. Then, again, the mercury spectrum is extremely useful in spectroscopic work as a reference spectrum.

scholarly journals Studies on the Myoneural Physiology of Echinodermata

1963 ◽  
Vol 40 (4) ◽  
pp. 713-726
Author(s):  
R. E. BOLTT ◽  
D. W. EWER
Keyword(s):  
Ultra Violet ◽  
Retractor Muscle ◽  
Mercury Vapour ◽  
Light Stimulation ◽  
Light Pulses ◽  
Rhythmical Activity ◽  
Mercury Vapour Lamp ◽  
Initial Depression ◽  
Simple Summation ◽  
Rapid Contraction

1. The lantern retractor muscle of Parechinus angulosus responds to light stimulation by a rapid contraction which is followed by a slower increase in tension. The details of these contractions vary from preparation to preparation. 2. With very brief light exposures only the quick response is shown, while with prolonged light stimulation rhythmical activity develops after a minute or more. 3. Exposure of a contracting preparation to the light of a mercury vapour lamp causes a slight fall in tone. This is not due to the ultra-violet component of this light. 4. Responses to repeated light pulses may result in simple summation or the response to the first pulse may be markedly greater than those which follow. In preparations which show this latter effect, there is evidence for an inhibitory phenomenon which persists for about 30 sec. 5. With paired stimuli the response to the second stimulus may show an initial depression which reaches a maximum at an interval of about 10 sec., then a recovery and finally a second depression of response which is maximal when the interval between stimuli is about 5 min. 6. There is evidence that stimulation of the comminator muscles may result in loss of tone of the lantern retractor muscles. 7. A provisional hypothesis to explain these effects is presented.

scholarly journals Effects of ultra-violet rays upon skeletal muscle

1927 ◽  
Vol 101 (706) ◽  
pp. 24-29 ◽  
Keyword(s):  
Skeletal Muscle ◽  
Calcium Ions ◽  
Ultra Violet ◽  
Mercury Vapour ◽  
Silk Thread ◽  
Nutritive Solution ◽  
Involuntary Muscle ◽  
Rhythmical Movement ◽  
Mercury Vapour Lamp ◽  
Nerve System

Leonard Hill and the author have studied the contracture of involuntary muscle produced by radiation with ultra-violet rays, and the author has shown that the presence of calcium ions in the nutritive solution is necessary for this contracture. The mechanism of the contracture produced by these rays is still undetermined. Leo Adler considers it due to changes in the cells of the involuntary muscles, and not to excitation of the vegetative nerve system, which has so great an influence upon rhythmical movement as well as tonus. On the suggestion of Dr. Leonard Hill the author investigated the action of the rays on skeletal muscle, but before doing so studied the effect of exposing various materials (cotton, linen, artificial silk and real silk-thread) to the mercury-vapour lamp. There might be a slight shortening of such fibres, but no remarkable difference in length occurred on irradiation. Tendon or skeletal muscle behaves quite differently from such dead fibres, showing distinct shortening on irradiation.

scholarly journals Growth under Vita Glass

1932 ◽  
Vol 32 (2) ◽  
pp. 211-218 ◽  
Author(s):  
Ian N. Sutherland
Keyword(s):  
Window Glass ◽  
Growth Curves ◽  
Ultra Violet ◽  
Normal Rate ◽  
Mercury Vapour ◽  
Short Discussion ◽  
Natural Sunlight ◽  
White Rats ◽  
Quartz Mercury ◽  
Mercury Vapour Lamp

White rats reared from the age of 30 days to 275 days under vita glass, and properly fed, do not grow at a different rate from those reared under ordinary glass.The offspring of these rats, kept in the same environment, grow at the normal rate when compared with controls born and reared under ordinary window glass.A short discussion of these results is given in the text.Addendum. The temptation to use an artificial source of ultra-violet rays having proved irresistible, a further experiment was performed with 20 males, 10 under vita glass and 10 under window glass. These were exposed to the radiation of a Hanovia quartz mercury vapour lamp on alternate days, at a distance of four feet from the burner. The growth curves are shown on Chart V, and the lengths of exposure have been entered on this chart: it will be seen that the results are the same as with natural sunlight.

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