摘要:

A crude extract ofAscaris lumbricoidesstrongly inhibits pepsin and trypsin but not papain; the extract shows no proteolytic activity. An active trypsin inhibitor was isolated by fractional precipitation. It is not precipitated by trichloracetic acid and has the properties of a polypeptide.The inhibitor acts instantaneously on trypsin, exerting its maximum effect at neutral and acid reactions, with a minimum at pH 5. The effect of concentration suggests a reversible combination between enzyme and inhibitor. The inhibitor has no effect on papain, but stimulates peptic digestion.

ISSN:1923-4287    

DOI:10.1139/cjr41b-013

出版商:NRC Research Press    

年代:1941

数据来源: NRC

摘要:

Under the conditions prescribed for the Pett test, which is described, it has been found that: (i) antecedent light does not affect the median of the three tests usually performed; (ii) no error results from the wearing or not wearing of glasses; (ii) the use of pilocarpine to contract the pupils is not advisable; (iv) some light may be admitted into the test room; (v) the time of exposure to the bright light (30 sec.) is suitable; (vi) repeated tests cause a 'learning' effect so rarely as to be of little concern; (vii) the standard error of the mean is ±1.4 and of the median is ±2.4 sec. Some results are presented suggesting that a diurnal rhythm in the vitamin A content of the blood exists.

ISSN:1923-4287    

DOI:10.1139/cjr41b-014

出版商:NRC Research Press    

年代:1941

数据来源: NRC

摘要:

When the isotropic hexahydrate of tricalcium aluminate is dehydrated, calcium oxide is liberated with the formation of a calcium aluminate lower in lime. A quantitative study of this reaction was made in order to determine the composition of the aluminate formed. Errors due to impurities in the tricalcium aluminate used, incompleteness of hydration to the hexahydrate, carbonation during treatment, retention of water by the final product, and recombination of the free lime with the aluminate formed were eliminated. The results indicated the formation of an aluminate of the composition 12CaO∙7Al2O3.The aluminate formed during the dehydration was found to give the same X-ray diffraction pattern as apparently homogeneous samples of the compositions 5CaO∙3Al2O3and 12CaO∙7Al2O3prepared directly from lime and alumina by thermal methods. The results support the assumption that the so-called "5:3" calcium aluminate should be assigned the formula 12CaO

ISSN:1923-4287    

DOI:10.1139/cjr41b-015

出版商:NRC Research Press    

年代:1941

数据来源: NRC

摘要:

A modification of the Kaye apparatus for the determination of moisture by distillation and of lipids by isopropyl ether extraction is described. The modified apparatus has been used in the analysis of plant material and faeces, and typical results are presented. It appears that isopropyl ether and ethyl ether yield similar amounts of extract, but that oven-drying may result in values that are too low.

ISSN:1923-4287    

DOI:10.1139/cjr41b-016

出版商:NRC Research Press    

年代:1941

数据来源: NRC