Pressure inactivation of microorganisms

Abstract

The kinetics of inactivation by hydrostatic pressure is measured for Pseudomonas aeruginosa, Staphylococcus aureus, Escherichia coli, bacteriophage T4, and the spores of Bacillus subtilis. Temperature and pressure effects are discussed as well as the interrelation between germination and inactivation in the case of bacterial spores.     

Experimental Study of the Influence of Different Load Changes in Inlet Gas and Solvent Flow Rate on CO2 Absorption in a Sieve Tray Column

An experimental study was conducted in a sieve tray column. This study used a simulated flue gas consisting of 30% CO₂ and 70%. A 10% mass fraction of methyl diethanolamine (MDEA) aqueous solution was used as a solvent. Three ramp-up tests were performed to investigate the effect of different load changes in inlet gas and solvent flow rate on CO₂ absorption. The rate of change in gas flow rate was 0.1 Nm³/h/s, and the rate of change in MDEA aqueous solution was about 0.7 NL/h/s. It was found that different load changes in inlet gas and solvent flow rate significantly affect the CO₂ volume fraction at the outlet during the transient state. The CO₂ volume fraction reaches a peak value during the transient state. The effect of different load changes in inlet gas and solvent flow rate on the hydrodynamic properties of the sieve tray were also investigated. The authors studied the correlation between the performance of the absorber column for CO₂ capture during the transient state and the hydrodynamic properties of the sieve tray. In addition, this paper presents an experimental investigation of the bubble-liquid interaction as a contributor to entropy generation on a sieve tray in the absorption column used for CO₂ absorption during the transient state of different load changes.     

Dynamic diffraction and interband transitions in two-dimensional photonic lattices

We reveal a direct link between two fundamental wave phenomena in periodic media, Pendell?sung oscillations and resonant coupling between spectral bands. We experimentally measure the power transfer between laser beams associated with the high-symmetry points in periodic and biased hexagonal photonic lattices. As a result, we demonstrate that Pendell?sung oscillations dominate the dynamics of resonant interband transitions on a short propagation scale.     

Antibody purification by affinity chromatography based on small molecule affinity ligands identified by SPR-based screening of chemical microarrays

Libraries of small molecules were searched for Fc-fragment selective binders to a recombinant human antibody ("MDJ8″, IgG(1)-subtype, κ-light chain) via SPR-based screening of chemical microarrays. Identified hit structures were immobilised on NHS-activated Sepharose for the determination of MDJ8 binding and selectivity versus typical proteineous impurities represented by the spend cell culture supernatant. Columns were packed and the most promising ligands further characterized in terms of binding constants, binding kinetics, as well as dynamic and equilibrium binding capacities. The performance of the best ligand, 2A10, was compared to standard Protein A chromatography. Using ligand 2A10 antibody capture from unprocessed cell culture supernatants was possible at similar recovery yield (>90%), purity (>80%), and eluting concentration (approximately 1 g/L) as with Protein A. Affinity constants (K(d)) of 2A10 were an order of magnitude higher than for the Protein A material, but still in the nM-range, while maximum binding capacities and binding kinetics were in the same order of magnitude. Ligand 2A10 was also able to capture a murine monoclonal antibody, again with similar efficiency as Protein A, as well as a number of humanised therapeutic antibodies. Antibody elution from the 2A10 column was possible using the Protein A standard protocol, i.e. 100mM glycine HCl pH 3.0, but also at near physiological pH, when some organic solvent or modifiers were present. Ligand 2A10 thus constitutes a cheaper, more robust alternative to Protein A as possible generic antibody binder. Moreover, the outlined approach to ligand selection could in principle by used to create suitable affinity ligands for other high value biotech products.