Alfred J. Richard

Ultracentrifugal studies of the isothermal compressibilities of organic alcohols and alkanes. Correlation with surface tension

Abstract The isothermal compressibility, specific volume, and the dependence of each on pressure, have been determined for several organic alcohols, alkanes, and alkenes by analytical ultracentrifugation. The variation of surface tension of liquids with pressure, at 0.1 MPa, has also been calculated. It was found to be constant for homologous alcohols up to C 9 and also for linear and branched alkanes up to C 10 .

Low-pressure studies of the isothermal compressibilities and specific volumes of organic liquids

Abstract The Spinco E analytical ultracentrifuge has been used to determine the isothermal compressibilities and specific volumes of a series of 13 organic liquids at pressures from 0.1 to 10 MPa at 293.15 and 298.15 K. Trends in the results suggest that rigidity of molecular structure decreases compressibility. Cyclization of C 6 compounds decreases compressibility.

Immunochemical and serological studies of enzymatically fragmented human IgG globulins—II: Hydrolysis with subtilisin, elastase, trypsin, and chymotrypsin

Abstract Fragmentation of the IgG globulins of a single anti-Rh serum by trypsin, chymotrypsin, subtilisin and elastase is compared to previous studies using papain, pepsin, ficin and bromelin. Natural antibodies in human sera are able to differentiate the Fab fragments produced by the different enzymes.

An inert liquid marker for density gradient ultracentrifugation in CsCl.

Abstract An inert perfluorodated liquid (FC-78) has been found that may be used as a density marker during density gradient centrifugation of DNA in CsCl. The isothermal compressibility of FC-78 at 25°C has been measured at pressures up to 280 atm.

The isolotion of serologically active peptides of low molecular weight from a hydrolyzate of bovine plasma albumin

Abstract Nine peptide fractions, ranging in molecular weight from 3200 to 6800, have been isolated by paper electrophoresis from an ultrafiltrate of a chymotryptic hydrolyzate of bovine plasma albumin. All these peptide fractions formed specific precipitates with antiserum against bovine plasma albumin, but the concentration necessary was approximately 1000 times that required for albumin.

The isothermal piezooptic coefficient of n-alkanes, n-alcohols, and some substituted benzenes

The isothermal piezooptic coefficients (∂n∂p)T of 27 pure liquids have been measured with an ultracentrifuge equipped with laser optics, in good agreement with available literature values. The isotropic part (R1s) of light scattered by pure liquids has also been calculated. A decrease in R1s has been observed with increasing chain length of n-alkanes. For n-alcohols R1s remains constant at least up to nonanol.

Factors influencing bonding of bromelain agglutinators and their Fab fragments.

The complex of bromelain agglutinators and their homologous Fab fragments is dissociated by gel chromatography under certain conditions. When albumin is present as a source of thiol groups, Fab fragments previously treated with N-ethylmaleimide (NEM) will dissociate from the agglutinators (fluid phase). If anti-Rh Fab fragments are bound to Rh-positive erythrocytes, the agglutinates are not dissociated by thiols (cellular phase). Prior to erythrocyte sensitization, the agglutinator site on Fab fragments can be blocked by thiol-disulfide exchange. Once the Fab fragments are coated on erythrocytes, the agglutinator site is more readily available than it was prior to sensitization, as evidenced by inhibition with 0.01 M NEM. The differences between the bonding characteristics of the fluid phase and the cellular phase and the influence of mercaptoalbumin on the agglutinator-Fab complex suggest that the agglutinators are not antibodies.