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Biomedical subjects

H L Frisch

Publications and source records attributed to H L Frisch.

29 records · Page 2Linked to original sources
PubMed1982

Theory of periodic structures in lipid bilayer membranes.

An approximate, new model for the structure of the periodic, undulated P(beta'), phase of phosphatidylcholine bilayers is proposed. The properties of this phase are deduced by minimizing a Landau-de Gennes expression for the bilayer free energy when this free energy contains a term favoring a spontaneous curvature of the membrane. The theoretical calculation leads to a model for the P(beta') phase of phosphatidylcholine bilayers having a number of novel physical properties, including periodic variations in membrane "fluidity."

Journal Article↗
PubMed1979

Dynamics of skeletal pattern formation in developing chick limb.

During development of the embryonic chick limb the skeletal pattern is laid out as cartilaginous primordia, which emerge in a proximodistal sequence over a period of 4 days. The differentiation of cartilage is preceded by changes in cellular contacts at specific locations in the precartilage mesenchyme. Under realistic assumptions, the biosynthesis and diffusion through the extracellular matrix of a cell surface protein, such as fibronectin, will lead to spatial patterns of this molecule that could be the basis of the emergent primordia. As cellular differentiation proceeds, the size of the mesenchymal diffusion chamber is reduced in descrete steps, leading to sequential reorganizations of the morphogen pattern. The successive patterns correspond to observed rows of skeletal elements, whose emergence, in theory and in practice, depends on the maintenance of a unique boundary condition at the limb bud apex.

Animals↗
PubMed1977

Sex stereotypes in adult-infant play.

24 14-month-old infants played with adult strangers in a laboratory playroom. To examine the effects of sex-role labeling on adult behavior, each infant was introduced as a boy and as a girl in 2 different sessions. After controlling for the adult's scores on the Spence-Helmreich Attitudes toward Women Scale, the adults were found to engage in more Encouragement for Activity and more Male Role Toy Choice when playing with children designated as boys. They showed more Interpersonal Stimulation and more Nurturance Play when playing with children designated as girls. No significant differences were observed between the behavior of the real girls and boys. Men and women showed some differences in their style of play.

Attitude↗
PubMedDate not supplied

Monte Carlo simulation of DNA electrophoresis.

This paper describes an attempt to study the electrophoresis mobility of a DNA molecule in a gel by means of a Monte Carlo simulation. We find that the electrophoresis mobility mu can be well described by the empirical equation mu v kappa 1/N + kappa 2E2 with N being the number of monomers of the model chain and E being the applied field. For small E the data can merge into the linear response result mu = kappa 1/N. The paper also discusses necessary extensions of the present approach.

Computer Simulation↗