Bernard S. Wildi

Electrical Properties of Poly‐Copper Phthalocyanine

Hall effect and electrical resistivity measurements as a function of temperature to ∼450°C have been carried out on a polymer of copper phthalocyanine. From the Hall effect data it is concluded that intrinsically the polymer of copper phthalocyanine is P type. Two states of this polymer have been determined, one has an activation energy of 0.26 ev and a carrier density ∼1016/cm3 (the carrier concentration varying with temperature), a second, a heat‐treated polymer, also shows P type conductivity but the carrier density is ∼1018/cm3 and is constant in the range of temperature measured. The mobility in the heat‐treated polymer is found to increase with increasing temperature. N type conductivity observed on the first structure is believed to be a consequence of impurities.

Bacillus cereus neutral protease

Abstract 1. 1.Bacillus cereus protease has been purified from culture filtrates by acetone precipitation, treatment with active charcoal, (NH4)2SO4 fractionation and chromatography over hydroxylapatite and DEAE-cellulose. 2. 2.The enzyme has been shown to be a zinc-containing neutral protease. 3. 3.The specificity towards a series of furylacryloyl dipeptides was similar to that of the neutral proteases from Bacillus subtilis and Bacillus megaterium and thermolysin. 4. 4.The B. cereus enzyme partially crossreacted with anti-thermolysin serum with loss of activity but did not crossreact with antisera to either the B. megaterium nor B. subtilis neutral proteases.

Lysolecithin-induced fusion of fibroblasts

SummaryLysolecithin has been used to induce cell fusion between two metabolically deficient mouse fibroblast lines, A9 and B82. Attempted fusion in suspension led to excessive cell clumping and complete loss of viability. Addition of lysolecithin solutions to confluent monolyers caused extensive detachment of cells from glass or plastic surfaces. At higher levels of lysolecithin few cells survived. When the conditions were controlled (50 to 250 μg per ml for up to 20 min), extensive polykaryocyte formation was observed. In the presence of selective medium (HAT) colonies of hybrid cells grew and a series of cell strains were isolated. The presence of inosinic acid pyrophosphorylase (absent in A9 cells) was demonstrated in the hybrid cells which were shown to have almost double the cell volume of the parent A9 and B82 cells. Unlike the parent cell lines, the hybrid cells grew well in the presence of HAT both as monolayers and in suspension.

Growth of anchorage dependent mammalian cells on glycine-derivatized polystyrene in suspension culture

SummaryGlycine-derivatized polystyrene beads were prepared and used as microcarriers to grow normal cells of human embryonic kidney, rhesus monkey kidney, and human foreskin fibroblasts in suspension cultures. Growth of the cells on polystyrene beads derivatized with other amino acids, peptides, and carboxylic acids also was investigated.

Semiconducting Organic Polymers Derived from Nitriles. Thermoelectric Power and Thermal Conductivity Measurements

The thermal conductivities and thermoelectric powers of two previously reported polymeric organic semiconductive materials are reported. One system, thought to be a form of oxidized polyphthalocyanine, shows very complex behavior on heating in the presence of oxygen. The thermoelectric power is very sensitive to this treatment but the electrical resistivity, although changing slightly, is relatively insensitive. Two different oxygen—polymer effects, one reversible and one irreversible, appear to be superimposed in this system.

Mammalian cell culture: technology and physiology.

During the last decade phenomenal advances have taken place in large-scale mammalian cell culture both for microcarriers and suspension methods. The cost of serum and product quality require that such systems be examined in terms of both their physical and chemical parameters. Data are presented as to the method used to more than double the final harvest cell density of 100-liter batch culture reactors by simple temperature measurements and 12-liter reactors by increasing the oxygen potential of the liquid. The results are interpreted in terms of physical transport phenomena of momentum, heat and mass via the theoretical relationships of Navier -Stokes, Fourier and Fick respectively. In addition, data are presented of 3-, 12-, and 100 liter reactors that the spent cell growth media were analyzed for ten different chemistries. The Monod cell growth curve was used to interpret the results. The cost savings and product quality improvements can be enormous by approaching both the technology and physiology of mammalian cell culture from the vantage points of chemistry, thermodynamics and transport phenomena.