REPAIR OF PSORALEN PLUS NEAR ULTRAVIOLET LIGHT DAMAGE IN BACTERIOPHAGES T3 AND T4

Abstract— Repair of T3 and T4 DNA damaged by treatment with 8-methoxypsoralen plus near UV (PNUV) has been investigated. It is shown that the excision repair mechanisms of the host cell can repair a substantial fraction of the psoralen-DNA mono-adducts in T3 DNA, but cannot by themselves repair crosslinks. In contrast neither the excision repair system of the host nor the phage coded v gene endonuclease is involved in the repair of psoralen adducts in T4 DNA. Multiplicity reactivation is effective in the recovery of T4 DNA containing psoralen-DNA mono-adducts, but is ineffective in the recovery of crosslinked phages. Comparisons of the lethality of PNUV treatment and the number of crosslinks induced in T4 DNA show clearly that mono-adducts are lethal to this phage. Both T3 and T4, however, appear to effectively repair many mono-adducts by postreplicational repair.     

On the solid solution of the spinel phase in the system NiO-Al2O3

The solid solubility of Al₂O₃ in NiAl₂O₄ spinel has been investigated by powder X-ray diffraction of samples prepared by solid state synthesis. The solid solution region found was in agreement with a previous report. The cubic cell parameter of the spinel solid solution was observed to decrease with increasing alumina content. Spinel with high alumina content was shown to be close to an inverse spinel as previously reported for stoichiometric NiAl₂O₄ and the inversion parameter proved to be relatively independent of the overall composition.     

Application of the CPA equation of state to reservoir fluids in presence of water and polar chemicals

The complex phase equilibrium between reservoir fluids and associating compounds like water, methanol and glycols has become more and more important as the increasing global energy demand pushes the oil industry to target reservoirs with extreme or complicated conditions, such as deep or offshore reservoirs. Conventional equation of state (EoS) with classical mixing rules cannot satisfactorily predict or even correlate the phase equilibrium of those systems. A promising model for such systems is the Cubic-Plus-Association (CPA) EoS, which has been successfully applied to well-defined systems containing associating compounds. In this work, a set of correlations was proposed to calculate the CPA model parameters for the narrow cuts in ill-defined C₇₊ fractions. The correlations were then combined with either the characterization method of Pedersen et al. or that of Whitson et al. to extend CPA to reservoir fluids in presence of water and polar chemical such as methanol and monoethylene glycol. With a minimum number of adjustable parameters from binary pairs, satisfactory results have been obtained for different types of phase equilibria in reservoir fluid systems and several relevant model multicomponent systems. In addition, modeling of mutual solubility between light hydrocarbons and water is also addressed.     

Untersuchung von Fleisch, Fleischerzeugnissen und Fleischbestandteilen

Ohne Zusammenfassung     

Untersuchung von Fetten und fettartigen Stoffen

Ohne Zusammenfassung     

2-(p -toluidino)-6-naphthalene sulfonate as a fluorescent probe for flocculation studies of cationic potato amylopectin and nanosized silica particles. 2. Flocculation by binding of nanosized silica particles

2-(p-toluidino)-6-naphthalene sulfonate (TNS) is a probe that fluoresces strongly when bound to certain proteins and polymers, but weakly in aqueous solutions. The reversible association of TNS is used to monitor the binding of anionic nanosized silica particles (NSP) to cationic potato amylopectin starch (CApS) through the decreasing fluorescence emission as TNS is competitively released by the particle binding. Steady-state fluorescence measurements at different mixing ratios of CApS and NSP provide data on the equilibrium binding. The isotherm derived is used to establish the fact that the most efficient flocculation between CApS and NSP occurs when the polymer coils are nearly saturated by NSP, but still have positively charged parts left. This supports a patch-flocculation mechanism. Stopped-flow experiments show that NSP binding to CApS occurs within a few milli seconds. This observation allows turbidity changes which occur on longer timescales to be ascribed to particle-decorated polymers undergoing changes in the conformation or aggregation. Received: 14 August 1998 Accepted in revised form: 4 December 1998