Ultrasound pasteurization: the effects of temperature, soluble solids, organic acids and pH on the inactivation of Escherichia coli ATCC 25922

The objectives of this research were to study the effects of temperature, sugar concentration (8, 12, and 16 g/100ml), organic acids (citric and malic acids) and pH (2.5 and 4.0) on ultrasound pasteurization. The model organism used for the research was Escherichia coli ATCC 25922, and ultrasound treatment times were conducted to achieve a 5 log (base 10) reduction. Ultrasound generates heat, therefore the study involved removing the heat using a jacketed beaker with refrigerant (-30 degrees C) to maintain processing temperature at or below 30 degrees C and eliminate the thermal inactivation effects. Overall, ultrasound increased the sensitivity of E. coli to thermal inactivation. The presence of soluble solids had a protective effect where the sonication time requirement increased. Similar to heat sensitivity, the lower pH environment resulted in E. coli having less resistance to sonication. The type of organic acid had the least significant effect on ultrasound inactivation of E. coli.     

The enthalpy of formation of 2II CH

The standard enthalpy of formation, δ_fH^o, of² II CH has been determined at converged levels of ab initio electronic structure theory, including high order coupled cluster and full configuration interaction benchmarks. The atomic Gaussian basis sets employed include the (aug)-cc-p(C)VXZ family with X = 3, 4, 5 and 6. Extrapolations to the complete one-particle basis set and the full configuration interaction limits, where appropriate, have been performed to reduce remaining computational errors. Additional improvements in the enthalpy of formation of ²II CH were achieved by appending the valence-only treatment with core-valence correlation, relativistic effects including spin-orbit correlation, and the diagonal Born-Oppenheimer correction. The recommended values for δfH^o ₀ and δA_f H _o ²⁹⁸ of ²II CH are 592.48^+0.47 _?0.56 kJ mol_?1 and 595.93 ^+0.47 _?0.56 kJ mol_?1, respectively.     

Anatomy of relativistic energy corrections in light molecular systems

Relativistic energy corrections which arise from the use of the Dirac-Coulomb Hamiltonian, and the Gaunt and Breit interaction operators, plus Lamb-shift effects have been determined for the global minima of the ground electronic states of C₂H₆, NH₃, H₂O, [H,C,N], HNCO, HCOOH, SiC₂, SiH^? ₃, and H₂S, and for barrier characteristics for these molecular systems (inversion barrier of NH₃ and SiH^? ₃, barrier to linearity of H₂O, H₂S, and HNCO, rotational barrier of C₂H₆, difference between conformations of HCOOH (Z/E) and SiC₂ (linear/T-shaped), and isomerization barrier of HCN/HNC). The relativistic calculations performed at the Hartree-Fock and the highly correlated CCSD(T) levels employed a wide variety of basis sets. Comparison of the perturbational and the four-component fully variational results indicate that the Coulomb-Pauli Hamiltonian and the lowest order Hamiltonian of direct perturbation theory (DPT(2)) are highly successful for treating the relativistic energy effects in light molecular systems both at a single point on the potential energy hypersurface and along the surface. Electron correlation contributions to the relativistic corrections are relatively small for the systems studied, and are comparable with the 2-electron Darwin correction. Corrections beyond the Dirac-Coulomb treatment are usually rather small, but may become important for high accuracy ab initio calculations.     

Investigation of Thermal Degradation of PVC in the Solid State

The thermal degradation of PVC powders and the inhibition of this process by cadmium laurate was investigated by the measurement of discoloration, diffuse reflectance spectra, and the quantity of hydrochloric acid formed. Kinetic analysis of the data obtained by us previously showed that both the data of color measurements and those of diffuse reflectance spectra may be used conveniently for the calculation of the number of double bonds formed during the degradation.     

Gas-chromatographic determination of a mixture of testosterone and oestradiol esters in oily injection

Summary A gas-liquid chromatographic method is described for the determination of testosterone and oestradiol esters in oily injection. The separation of the steroids from the injection is performed by partition in the acetonitrile-hexane system. For gas chromatography the oestradiol esters were preliminary transformed to their mono-TMS derivatives. For the separation Dexsil 400 was preferably used as stationary phase. Mestranol was employed as internal standard for quantitation. A complete separation for all the individual components can be achieved within 12 min. The relative standard deviation is in the range of 1–1.5%.

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Gas-chromatographische Bestimmung eines Gemisches von Testosteron- und Östradiolestern in öliger Injektionslösung

Zusammenfassung Die Abtrennung der Steroide aus der Injektionslösung erfolgt durch Extraktion mit Acetonitril und n-Hexan. Zur Gas-Chromatographie werden die Östradiolester in die Mono-trimethylsilylderivate übergeführt. Als stationäre Phase dient vorzugsweise Dexsil 400. Zur quantitativen Bestimmung wird Mestranol als inneren Standard benutzt. Eine vollständige Trennung der Ester läßt sich innerhalb von 12 min erreichen. Die relative Standardabweichung liegt im Bereich von 1–1,5%.