Non-invasive monitoring of protein adsorption and removal in a turbulent flow cell

A flow cell was designed for continuous non-invasive measurements of macromolecular adsorption and removal under well-defined flow conditions. The adsorption of the protein beta-lactoglobulin to stainless steel surfaces and its subsequent detergent-induced removal were followed in the flow cell using in situ ellipsometry under both laminar and turbulent conditions. Factors varied include the cleaning agent type and concentration, the flow rate and the protein concentration. In addition, the experiments studying different cleaning agents were repeated in a stirred cuvette system employed in previous work. The ellipsometer as well as the experimental set-ups are described, with particular emphasis on the flow cell design. Evaluation of the results is done by comparing the amounts of protein adsorbed from solution, the initial adsorption rates, the amounts removed in water or detergent and the residual amounts after cleaning. The results are discussed in terms of beta-lactoglobulin unfolding, preferential adsorption, different states of adsorbed molecules, additional physicochemical aspects and hydrodynamic characteristics.     

Recombination processes related to Eu2+ energy level position in ionic CaxCd1-xF2 crystals

Abstract

We study efficiency of autoionization and recombination transitions for europium in Ca_xCd_1-xF₂ host lattice depending on the energy level position of Eu²⁺ 4f⁶5d¹(e) excited states in respect to the conduction band (CB) states. From photoluminescence (PL) and absorption measurements we conclude that for x in the range of 1 - 0.65 thermalization within the 4f⁶5d¹(e) multiplet is faster than the appropriate autoionization transition. For x > 0.65, when all the excited 4f⁶5d¹ states are degenerate with the CB autoionization is immediate, Eu²⁺ intra-ion emission is quenched and a new Eu-related emission appears, which we tentatively assign to a radiative capture emission of hot nonequilibrium electrons.     

水解—— 空气提升反应器处理生活污水

水解──空气提升反应器处理生活污水吴锡福，陈红英（浙江工业大学土木工程系杭州３１００３２）我们把水解（酸化）和空气提升反应器的工艺结合起来，设计成一体化的设备，对我校一幢教学大楼的生活污水做了小试，处理效果良好，该处理工艺流程如图１所示．污水先经水解...     

Measurements and analysis of high-intensity turbulent characteristics in a turbine-agitated tank

Turbulent flow in the impeller zone and the bulk zone in a turbine-agitated tank was measured by constant temperature anemometry. A split-film probe was used which sensed the directionality of the flow. Turbulent characteristics such as intensity and anisotropy were expressed by statistical moments for all three directions of flow. Turbulent kinetic energy and mean Reynolds stresses were also calculated. The convective velocity was estimated from Taylor's hypotheses as well as from other hypothesis and approximations which considered both the mean velocity and the fluctuations of the flow. The local energy dissipation rates were calculated using three different methods. They were based on energy dissipation spectrum. Kolmogorov's hypotheses and dimensional analysis. The method based on Kolmogorov's hypotheses is suggested here. Received: 4 February 1997 / Accepted: 22 May 1998     

Effects of Heavy Ion Irradiation on Short-Range Order of Fe–Cr–P–C Amorphous Alloys Investigated by Mössbauer and DSC Measurements

Rapidly quenched Fe–Cr–P–C amorphous alloys irradiated with 209 MeV energy ⁸⁴Kr ions were investigated by Mössbauer spectroscopy, X-ray diffraction, and differential scanning calorimetry measurements. Significant changes were found between Mössbauer spectra of the irradiated and non-irradiated amorphous alloys. The changes were analysed by the hyperfine field distribution method, too. The crystallisation temperature as well as the phase composition at a certain stage of crystallisation were found to be different in the non-irradiated and irradiated samples. These results reflect the changes in the short-range ordering due to the irradiation with energetic heavy ions.     

Über ausgezeichnete Tangenten einer regulären Kurve

Ohne Zusammenfassung     

Antimicrobial activity of new bicyclic lactones with three or four methyl groups obtained both synthetically and biosynthetically

Ten new derivatives of isophorone were obtained through a five-step synthesis. Among the products were several unsaturated, bicyclic lactones with three or four methyl groups. These lactones were used as the substrates for biotransformation mediated by selected fungal strains (Fusarium species, Syncephalastrum racemosum, Cunninghamella japonica, Penicillium species, Absidia species, and Pleurotus ostreatus). Four new hydroxylactones were obtained as a result of biotransformation. Because the unsaturated lactone with four methyl groups was a diastereoisomeric mixture, a structural analysis was conducted. The hydroxylactones were also included in this analysis. Both the unsaturated lactones and hydroxylactones were examined for their antimicrobial activity. It was found that some of these compounds exhibited growth inhibition against pathogenic strains of bacteria (Staphylococcus aureus, Pseudomonas fluorescens), yeasts (Candida albicans) and filamentous fungi (Alternaria sp., Penicillium sp.). All obtained compounds were also subjected to scent analysis.