Some elementary observations regarding reductive Cartan geometries

After defining generalizations of the notions of covariant derivatives and geodesics from Riemannian geometry for reductive Cartan geometries in general, various results for reductive Cartan geometries analogous to important elementary results from Riemannian geometry are proven using these generalizations. In particular, a generalization of the Hopf-Rinow theorem is given with a pleasantly concise proof.Comment: 8 pages, no figure

The conversion of citrulline to arginine in kidney

Glycocyamine is formed in the kidney by the transfer of the amidine group of arginine to the nitrogen atom of glycine. In the study of this reaction it was observed that glycocyamine was also formed from citrulline and glycine. No other donor or precursor of the amidine group was found (1)

Dimethylthetin and dimethyl-β-propriothetin in methionine synthesis

In a previous communication it was shown that choline and betaine are effective in promoting methionine synthesis from homocysteine in tissue homogenates (1). Data presented in this paper indicate that dimethylthetin, (CH3)2+SCH2COO-, which has been shown by Welch (2) to be lipotropic and has been reported by du Vigneaud (3) to promote growth on a methionine-free, homocysteine-containing diet, is 20 times as active as betaine in methionine formation. Dimethyl-β-propiothetin, (CH3)2+S(CH2)2COO-, recently isolated from Polysiphonia fastigiata by Challenger and Simpson (4) is also highly active. The enzyme for this transmethylation is found in the liver and kidney of all animals tested. Its high activity and general distribution suggest its biological importance in methionine synthesis

Classifying Families of Character Degree Graphs of Solvable Groups

We investigate prime character degree graphs of solvable groups. In particular, we consider a family of graphs $\Gamma_{k,t}$ constructed by adjoining edges between two complete graphs in a one-to-one fashion. In this paper we determine completely which graphs $\Gamma_{k,t}$ occur as the prime character degree graph of a solvable group.Comment: 7 pages, 5 figures, updated version is reorganize

Methionine formation by transmethylation in vitro

We reported in a previous communication (1) that guanidoacetic acid is methylated to creatine by rat liver slices in the presence of choline and either homocysteine or homocystine. Choline, homocystine, or homocysteine alone had little or no effect. These observations closed the gap which had existed between the evidence from tissue slice experiments on the one hand (2) and that from experiments in viva on the other (3-5) regarding the transfer of choline methyl in the formation of creatine