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Biomedical subjects

U E Loening

Publications and source records attributed to U E Loening.

At least 19 recordsLinked to original sources
PubMed1993

The ecological challenges to population growth.

Human societies have developed by overcoming the constraints of nature. The result is population growth that will exceed, and probably has already exceeded, the carrying capacity--it is the most dramatic period in the history of the planet. It is not only growth, but existing numbers and their demands, that destroy the ecological basis. The obligation on humanity now is to add to this success over nature a negative instead of a positive feedback system. There can be no simple technical answer; solutions must come from the co-ordinated attention to environment, population, poverty and equity. Most political social and economic institutions militate against the changes needed. Two approaches are outlined: a tool for thought for communities to determine their aims in terms of fundamental human needs, and a resource modelling system to assess whether such aims are physically possible.

Conservation of Natural Resources↗
PubMed1975

The ribosomal ribonucleic acid of Agrobacterium tumefaciens.

The 23S rRNA of Agrobacterium tumefaciens contains at least two nicks which result in the formation of RNA components with mol.wts. of 0.52 X 10(6) and 0.48 X 10(6). Thus under the usual conditions of extraction and analysis, no 23S rRNA was recovered from the bacterium. The experiments show that 23S rRNA is synthesized as a continuous chain, in which one or two nicks are formed almost immediately near the ends of the molecule and an additional nick in the middle at a later time.

Electrophoresis, Polyacrylamide Gel↗
PubMed1969

The determination of the molecular weight of ribonucleic acid by polyacrylamide-gel electrophresis. The effects of changes in conformation.

1. The effects of changes in experimental conditions on the mobility of RNA in polyacrylamide-gel electrophoresis were investigated. 2. The linear relation between log(molecular weight) and electrophoretic mobility was shown to be independent within limits of salt or gel concentration. 3. The relative mobility of RNA with low content of guanylic acid and cytidylic acid residues was decreased in low-ionic-strength buffer. This was related to a small relative decrease in sedimentation coefficient. 4. However, Mg(2+) ion caused almost no increase in mobility although it was associated with large increases in sedimentation coefficient. This suggested opposing actions of Mg(2+) ion on the size and effective charge of the RNA. 5. It is concluded that the method provides a satisfactory measurement of molecular weight, which is almost independent of the nucleotide composition of RNA at moderate salt concentrations.

Acrylates↗