Freda Wolfsheimer, transcript only

Transcript of an interview with Freda Wolfsheimer by Lucille Brown of Union College. Freda was born in 1897 in Weickersheim, Germany.https://digitalworks.union.edu/berkoralhistories/1011/thumbnail.jp

Insulin Receptors of Erythrocytes and Liver Membranes in Dogs.

Insulin receptor assays using canine liver membranes and erythrocytes were validated for use in evaluating insulin receptor binding parameters within a healthy population of dogs. Association, dissociation, saturability and specificity were demonstrated for insulin receptors of canine liver membranes and erythrocytes. Assay precision was evaluated by measuring interassay coefficient of variation (liver membrane = 25.0%; erythrocytes = 9.3%). Because the number of high-affinity receptor sites and high-affinity K\sb{\rm D} were determined using physiological concentrations of insulin, they were considered to be more physiologically important than the total number of receptor sites, low-affinity K\sb{\rm D} and Ke, which were derived using supra-physiological concentrations of insulin. The % maximum binding correlated with the number of high-affinity receptor sites and Ke, but negatively correlated with high-affinity K\sb{\rm D}.. In addition to correlating binding parameters within and between tissues, the effects of sex, anesthesia and prednisone treatment were evaluated. Erythrocyte insulin receptor binding did not correlate well with liver insulin receptor binding (3 samples of 12 dogs; Pearson\u27s correlation coefficient). This lack of correlation was possibly due to different mechanisms of receptor regulation or poor precision in the liver membrane assays. No significant differences were observed in mean values for binding parameters observed when comparing male versus female dogs for either liver membranes or erythrocytes using an unpaired t test (p $\u3e$ 0.05). However, there was a significantly greater variation in the % maximum binding and the number of high-affinity receptor binding sites for erythrocytes among females (Prob (a greater F) = 0.0405 % MB; 0.0035 Hi-Affinity Sites). A significant decrease in the % maximum binding of erythrocyte insulin receptors was observed as a result of anesthesia (paired t test; p = 0.028). No significant changes in erythrocyte insulin binding were observed in 6 male dogs given daily prednisone, when evaluated at 52 hours and 3 weeks after onset of treatment (paired t test; p $\u3e$ 0.05). Canine erythrocyte insulin receptors are a potentially valuable tool in evaluating clinical syndromes where alterations in insulin receptor binding may occur

The isotropic-nematic interface in suspensions of hard rods: Mean-field properties and capillary waves

We present a study of the isotropic-nematic interface in a system of hard spherocylinders. First we compare results from Monte Carlo simulations and Onsager density functional theory for the interfacial profiles of the orientational order parameter and the density. Those interfacial properties that are not affected by capillary waves are in good agreement, despite the fact that Onsager theory overestimates the coexistence densities. Then we show results of a Monte Carlo study of the capillary waves of the interface. In agreement with recent theoretical investigations (Eur.Phys.J. E {\bf 18} 407 (2005)) we find a strongly anistropic capillary wave spectrum. For the wave-numbers accessed in our simulations, the spectrum is quadratic, i.e.elasticity does not play a role. We conjecture that this effect is due to the strong bending rigidity of the director field in suspensions of spherocylinders.Comment: 8 pages, 10 figure

Hard colloidal rods near a soft wall: wetting, drying, and symmetry breaking

Within an Onsager-like density functional theory we explore the thermodynamic and structural properties of an isotropic and nematic fluid of hard needle-like colloids in contact with a hard substrate coated with a soft short-ranged attractive or repulsive layer. As a function of the range and the strength of the soft interactions we find wetting and drying transitions, a pre-drying line, and a symmetry-breaking transition from uniaxial to biaxial in the wetting and drying film.Comment: 7 pages, 2 figure

Isotropic-nematic interfacial tension of hard and soft rods: application of advanced grand canonical biased sampling techniques

Coexistence between the isotropic and the nematic phase in suspensions of rods is studied using grand canonical Monte Carlo simulations with a bias on the nematic order parameter. The biasing scheme makes it possible to estimate the interfacial tension gamma in systems of hard and soft rods. For hard rods with L/D=15, we obtain gamma ~ 1.4 kB T/L^2, with L the rod length, D the rod diameter, T the temperature, and kB the Boltzmann constant. This estimate is in good agreement with theoretical predictions, and the order of magnitude is consistent with experiments.Comment: 10 pages, 10 figure

Fluctuating Interfaces in Liquid Crystals

We review and compare recent work on the properties of fluctuating interfaces between nematic and isotropic liquid-crystalline phases. Molecular dynamics and Monte Carlo simulations have been carried out for systems of ellipsoids and hard rods with aspect ratio 15:1, and the fluctuation spectrum of interface positions (the capillary wave spectrum) has been analyzed. In addition, the capillary wave spectrum has been calculated analytically within the Landau-de Gennes theory. The theory predicts that the interfacial fluctuations can be described in terms of a wave vector dependent interfacial tension, which is anisotropic at small wavelengths (stiff director regime) and becomes isotropic at large wavelengths (flexible director regime). After determining the elastic constants in the nematic phase, theory and simulation can be compared quantitatively. We obtain good agreement for the stiff director regime. The crossover to the flexible director regime is expected at wavelengths of the order of several thousand particle diameters, which was not accessible to our simulations

Transfer matrix solution of the Wako-Sait\^o-Mu\~noz-Eaton model augmented by arbitrary short range interactions

The Wako-Sait{\^o}-Mu\~noz-Eaton (WSME) model, initially introduced in the theory of protein folding, has also been used in modeling the RNA folding and some epitaxial phenomena. The advantage of this model is that it admits exact solution in the general inhomogeneous case (Bruscolini and Pelizzola, 2002) which facilitates the study of realistic systems. However, a shortcoming of the model is that it accounts only for interactions within continuous stretches of native bonds or atomic chains while neglecting interstretch (interchain) interactions. But due to the biopolymer (atomic chain) flexibility, the monomers (atoms) separated by several non-native bonds along the sequence can become closely spaced. This produces their strong interaction. The inclusion of non-WSME interactions into the model makes the model more realistic and improves its performance. In this study we add arbitrary interactions of finite range and solve the new model by means of the transfer matrix technique. We can therefore exactly account for the interactions which in proteomics are classified as medium- and moderately long-range ones.Comment: 15 pages, 2 figure