摘要:

dl-Tryptophan-β-C14was fed to sprouting barley and radioactive gramine isolated from the shoots. Activity in the alkaloid resided entirely in one position, corresponding to that in the tracer administered to the plants, indicating that tryptophan is a precursor of gramine.

ISSN:0008-4042    

DOI:10.1139/v51-121

出版商:NRC Research Press    

年代:1951

数据来源: NRC

摘要:

Radioautographs of leaves of barley fed with C14-tryptophan have been taken at intervals. In the early stages of development a radioactive area appeared at the bottom of the leaves, which was due mainly to free tryptophan. Later an area, consisting mainly of gramine, developed at the top of the leaves.

ISSN:0008-4042    

DOI:10.1139/v51-122

出版商:NRC Research Press    

年代:1951

数据来源: NRC

摘要:

not available

ISSN:0008-4042    

DOI:10.1139/v51-123

出版商:NRC Research Press    

年代:1951

数据来源: NRC

摘要:

The activity after progressive aging and thermal treatment of silver permanganate supported on zinc oxide and beryllium oxide was found to be closely related to the extent of decomposition of the crystalline silver permanganate. The silver salt decomposed, with loss of active oxygen, to a relatively insoluble, amorphous product resembling a manganito-manganate of the composition, Ag2O Mn2O5or [AgMnO3]2. From a mass balance of solid–gas reactants in a reacting column, it was demonstrated that in the most active stage, during which the efficiency of oxidation did not fall below 90%, the course of the reaction was about evenly divided between stoichiometric and catalytic processes.

ISSN:0008-4042    

DOI:10.1139/v51-124

出版商:NRC Research Press    

年代:1951

数据来源: NRC

摘要:

Diphenylcyanamide is conveniently prepared by the action of cyanogen chloride on diphenylamine. When it is hydrolyzed in the presence of hydroxylated solvents, of the type ROH, stable isoureas are formed. These are readily hydrolyzed in aqueous alkaline medium to the corresponding urea derivative. Chlorination of diphenylcyanamide occurs in theparapositions yielding a nitrogen analogue of DDT. This chlorinated derivative is only 1/80th as toxic as DDT toSitophilusgranarius(L).

ISSN:0008-4042    

DOI:10.1139/v51-125

出版商:NRC Research Press    

年代:1951

数据来源: NRC

摘要:

Some diaminate and tetraminate addition compounds of silicon tetrachloride with butylamine, diethylamine, piperidine, triethylamine, and tributylamine have been prepared and analyzed. The tetraminates begin to decompose at temperatures above and below 200°C. The thermal stabilities and the products of the decompositions of these compounds indicate that coordinate bonds, and hydrogen bonds when possible, are involved in the formation of the tetraminates of silicon tetrachloride.

ISSN:0008-4042    

DOI:10.1139/v51-126

出版商:NRC Research Press    

年代:1951

数据来源: NRC

摘要:

The mercaptolysis of the α-and β-pentaacetyl derivatives of glucopyranose and galactopyranose at 0 °C. with zinc chloride catalyst was studied. The β-pentaacetates were rapidly transformed to the corresponding ethyl tetraacetyl-1-thio-β-D-glycosides in excellent yields; however, the α-anomers were highly resistant to the mercaptolytic conditions. The results are interpreted on the basis of a participation by the C2-acetoxy group in the replacements at the lactol carbon atom of the β-pentaacetates with the intermediate formation of a resonance stabilized cyclic carbonium ion.

ISSN:0008-4042    

DOI:10.1139/v51-127

出版商:NRC Research Press    

年代:1951

数据来源: NRC

摘要:

The photolysis of CH3CD2COCD2CH3has been studied over a temperature range from 25°C. to 365°C. The results confirm several features of the mechanism, previously proposed for the photolysis of diethyl ketone. It is concluded that disproportionation of ethyl radicals occurs by a "head to tail" mechanism. As activation energy for the reactiona valueE4 = 8.7 kcal. was found. As activation energy for Reaction (5)a value ofE5 = 11.7 kcal. was found. An activation energy of ∼ 17 kcal. is estimated for the thermal decomposition of the pentanonyl radical

ISSN:0008-4042    

DOI:10.1139/v51-128

出版商:NRC Research Press    

年代:1951

数据来源: NRC

摘要:

Measurements of osmotic pressures of polyvinyl acetate solutions in various solvents have been made. These pressures are precise to ±0.005 cm. of solvent and can be repeated on successive samples to 0.02 cm. In five solvents, plots of reduced osmotic pressure (π/C2) against concentration show distinct upward curvature which differs significantly from theoretical equations derived by Flory and by Huggins. The evidence suggests that further refinement of these theoretical equations is required to bring them into exact agreement with experimental data.

ISSN:0008-4042    

DOI:10.1139/v51-129

出版商:NRC Research Press    

年代:1951

数据来源: NRC

摘要:

The protective colloid indices have been determined on the sera of 83 normal rats and on 74 rats with transplanted Walker carcinosarcoma. As previously found with humans, the sera from tumor animals have much less of the protective colloids than the sera of normals. When 0.12 ml. of serum was used, 82% of the cancerous animal gave residual dye of less than 51γ per ml., whereas 100% of the normals gave concentrations above this value. Half of the false negative tests were from rats having tumors less than 15 gm. in weight. When 0.10 ml. of serum was used, 89.2% had an index below 15γ with an average of 7.8γ while the index of 91% of the normals was above 15γ with an average of approximately 42γ. The protective indices and polarograms have been compared for the sera of 43 cancerous and 47 normal rats. In 91% of the cancerous animals characteristic curves were obtained having a wave height greater than 50 mm., with 4.2% false positives in the normal group. The two tests are of approximately equal value in classifying the sera. The serum constituents responsible for the polar-graph wave are different from those indicated by the protective colloid index.

ISSN:0008-4042    

DOI:10.1139/v51-130

出版商:NRC Research Press    

年代:1951

数据来源: NRC