摘要:

Gliadin prepared by several different methods had the same nitrogen content and distribution. The critical peptization temperature (C.P.T.) in 60% alcohol and viscosity in 30% urea-buffer solutions, however, showed considerable variation, preparations of high C.P.T. (low solubility) being more viscous. This variation in the physical properties is explained by fractionation or denaturation incidental to the method of preparation.Gluten precipitated from 30% urea solutions at salt concentrations varying from 0.1 to 0.5 of saturation, yielded fractions that varied continuously in their gliadin and glutenin content, as judged from their percentage of arginine nitrogen.Gluten dispersed in buffered 30% urea solutions showed no change in viscosity during 101 hr. after the gluten was completely dispersed. A variation of hydrogen ion concentration between pH 6.0 and 6.95 had little effect on its viscosity. Heating at 70 °C. caused a marked decrease in the viscosity of this dispersion during the first hour. When gliadin dispersions are heated as above only samples having a high initial viscosity and C.P.T. become less viscous. Heating gliadin of natural moisture content (12 to 14%) at 70 °C. for varying periods of time did not change significantly its subsequent C.P.T. and viscosity in 60% alcohol. More severe heat treatments at higher moisture contents rendered the gliadin insoluble in 60% alcohol. Dilute alcoholic extracts of heated flours contained less protein than those of unheated controls. However, the C.P.T. of the former was lower than that of the latter. It is concluded from these experiments that when the gluten proteins are subjected to elevated temperatures, the glutenin fraction is first affected, next the gliadin fractions of low solubility, and finally, under severe conditions, all of the gliadin is denatured.

ISSN:1923-4287    

DOI:10.1139/cjr31-077

出版商:NRC Research Press    

年代:1931

数据来源: NRC

摘要:

Helminthosporium sativum, one of the most prevalent fungous pathogenes affecting the roots and other parts of wheat and related grass plants, grows and fruits readily as a saprophyte on various substrata. It might therefore be expected that it would be found in abundance in the soil. Attempts to isolate it directly from field soils by plating have been successful, but only in a small percentage of the trials. Failures are apparently largely attributable to the fact that this fungus does not sporulate commonly in ordinary field soils. This has been shown by direct microscopic examination of the soil and by artificial cultures. From a study of the latter it has been found thatH.sativumwill sporulate quite readily on several different soil types including sand if they are sterilized, but not if they are not sterilized.The fact that soils capable of supporting sporulation of this fungus may be rendered ineffective by adding small amounts of unsterilized soil, suggests that sporulation is inhibited by the saprophytic micro-organisms of the soil. It would appear that ifH.sativumoccurs in the soil, it must be present chiefly in the form of mycelium. Inability to form spores probably lessens the capability of this fungus to survive as well as to multiply in the soil.

ISSN:1923-4287    

DOI:10.1139/cjr31-078

出版商:NRC Research Press    

年代:1931

数据来源: NRC

摘要:

Four strains ofLeuconostoc mesenterioideshave been studied, and a medium suitable for the production of relatively large amounts of polysaccharide from sucrose has been carefully evolved. All of these organisms brought about polysaccharide formation in nutrient solutions containing sucrose, while two of them showed a slight activity in this respect toward glucose. Melezitose, raffinose, fructose, galactose, lactose, maltose, xylose and glycerol, when employed in the place of sucrose, did not yield any polysaccharide. It is not yet certain if a definite relation exists between the structure of the polysaccharide formed and the sugar utilized, as was found to be the case with levan (8, 9, 10).

ISSN:1923-4287    

DOI:10.1139/cjr31-079

出版商:NRC Research Press    

年代:1931

数据来源: NRC

摘要:

Additional evidence is given regarding the influence of polar radicals, or atoms, on the ease and nature of acetal condensations involving glycerol.Bromoethylidene glycerol has been prepared as a mixture of the isomeric five- and six-membered ring forms, by the condensation of bromoacetaldehyde with glycerol. This mixture was separated into the two isomeric forms by taking advantage of differences in the physical properties of their benzoates.The equilibrium ratio of six- to five-membered acetal at room temperature as obtained in the above preparation was found to be 1:15. Under the influence of 1% dry HCl at 25 °C. the ratio changed to 1:8.By conversion of the acetals into the methyl ethers, and comparison of these with the corresponding products of known constitution obtained by condensation of bromoacetaldehyde with glycerol α- and β-methyl ethers respectively, the identity of each of the acetals was established.A detailed description is given for the preparation of dibromoparacetaldehyde both in the crystalline form (50% yield) and as a crude syrup (75% yield).

ISSN:1923-4287    

DOI:10.1139/cjr31-080

出版商:NRC Research Press    

年代:1931

数据来源: NRC

摘要:

The two-component systems ethyl ether-hydrogen chloride and methyl alcohol-hydrogen chloride have been examined in the gaseous state, and from the pressure-volume-temperature relationship of the binary mixture evidence is adduced of the existence of compound formation. The heats of reaction appear to be constant in the temperature range investigated, and are 5400 calories for the ether hydrochloride, and 9200 calories for the alcohol hydrochloride. The pressure-volume-temperature data for ethyl ether, methyl alcohol and ethyl alcohol are given over the temperature range 50–200 °C., and over the pressure range below one atmosphere.

ISSN:1923-4287    

DOI:10.1139/cjr31-081

出版商:NRC Research Press    

年代:1931

数据来源: NRC

摘要:

An apparatus for the measurement of the vapor density of condensable gases at pressures greater than atmospheric and at various temperatures is described. The vapor density of redistilled hydrogen sulphide was measured at 47°, 25°, 0°, −20°, and −35 °C., and up to 4 atm. pressure. The interpolated value for the vapor density of hydrogen sulphide under standard conditions was found to be 1.537. This value agrees with the values given by Leduc (1.538) and Baume and Perrot (1.539), but the difference may be attributed in part to the neglect of the earlier experimenters to allow for deviations from the gas laws in correcting their values to standard pressure. The results are expressed as apparent molecular weights, and the deviations from the theoretical value shown to be due to the action of molecular attraction.

ISSN:1923-4287    

DOI:10.1139/cjr31-082

出版商:NRC Research Press    

年代:1931

数据来源: NRC

摘要:

A modified flow method has been devised for measuring the velocities of gas reactions, which enables observations to be made by pressure readings rather than by tedious analytical methods. In principle the method consists of passing the reactants through a flow-meter, then through a heated reaction chamber, and finally through a second flow-meter. The ratio of the two flow-meter readings, corrected for the change in the viscosities of the gases, gives a direct measure of the extent to which the reaction has progressed. As a test of the method the thermal decomposition of ammonia on the surface of silica has been investigated.

ISSN:1923-4287    

DOI:10.1139/cjr31-083

出版商:NRC Research Press    

年代:1931

数据来源: NRC

摘要:

The mathematics of fractional distillation of ideal mixtures has been condensed, so that the most economical "reflux ratio" for any such mixture may be decided at once.Particular use is made of the "critical reflux ratio" for any mixture, above which even an infinite column cannot obtain complete separation; and the relation of this critical value to the most economical value for any particular case is given.Some of the conclusions with respect to the infinite column were tested by means of a mixture of methyl and ethyl alcohols using a particularly efficient column. It was found that the vapor produced in the still contained slightly more than the theoretical amount of methyl alcohol, and the magnitude of such error is illustrated from previous work on glycerine solutions.The results are given in the form of a graph of the "critical reflux ratio" for the case where the most volatile constituent boils at 100 °C., and the difference between the boiling points varies from 0.25 °C. to 32 °C., the concentration of the most volatile constituent also being included from 0.001 to 1.0.A table of correction factors is also given, showing the factor by which the "critical reflux ratio" should be varied to produce the greatest economy of time for any particular case.

ISSN:1923-4287    

DOI:10.1139/cjr31-084

出版商:NRC Research Press    

年代:1931

数据来源: NRC

摘要:

A description is given of a simple and efficient apparatus for purifying radon, which has given several years effective service in connection with radium therapy. Potassium hydroxide is used to remove carbon dioxide and most of the water. Since phosphorus pentoxide for drying has been dispensed with, only one Toepler pump and fewer valves and stopcocks are necessary. The number of stopcocks has been reduced to three and there is but one large bulb and one float valve. The impurities are removed by sparking and allowing excess hydrogen to escape through a palladium tube heated electrically; thus there is no danger of clogging the tap with particles of loose reagent. All parts are made of Gundlach glass. Purification takes from two to five minutes.

ISSN:1923-4287    

DOI:10.1139/cjr31-085

出版商:NRC Research Press    

年代:1931

数据来源: NRC

摘要:

The results are set forth of an experimental examination of the action of high-speed electrons on the vapors of acetaldehyde, acetone, methyl alcohol and ethyl alcohol, on gaseous formaldehyde and on ethylene. It has been shown that cathode rays form polymerization compounds with formaldehyde, acetaldehyde and acetone and that these surfer decomposition into the simpler gases. The ultimate decomposition of acetaldehyde has been studied in some detail and has been shown to proceed through the polymer. Exposure to the rays results in the decomposition of methyl and ethyl alcohols with the formation of aldehydes, hydrocarbons, oxides of carbon and hydrogen. The conclusion has been drawn that dehydrogenation is the principle primary reaction in the decomposition of the alcohols, further decomposition proceeding through the aldehydes. Ethylene under the action of the rays yields an unsaturated liquid hydrocarbon which upon further bombardment gives hydrogen, acetylene and saturated hydrocarbons.

ISSN:1923-4287    

DOI:10.1139/cjr31-086

出版商:NRC Research Press    

年代:1931

数据来源: NRC