Dispersion and Phase Separation of Water‐Oil‐Amphiphile Systems in Stirred Tanks

Drop size distributions and phase separation behavior of water‐oil‐nonionic amphiphile systems are investigated using an in situ endoscope measurement technique and an external camera in stirred tanks in batch mode. The fitting procedure and the simulation results of a phase separation model are analyzed under the condition that either the swarm sedimentation speed or the mean drop size during sedimentation is known. The steady‐state drop size distributions are self‐similar over the whole range of process parameters, but not in the decaying turbulence field after agitation stop. The coalescence rate in the first seconds after agitation stop clearly affects the separation behavior, so that a prediction of the separation time based on the initial conditions in steady state is not trivial.     

Multilongitudinal-mode dynamics in a semiconductor laser subject tooptical injection

Multilongitudinal-mode dynamics in a semiconductor laser subject to optical injection are investigated both experimentally and numerically. We found that there are parameter regimes for which the slave laser hops into an adjacent longitudinal mode as we vary the detuning of the optical frequencies between the master and slave laser. A traveling wave model is used to numerically investigate the mode hopping. Good qualitative agreement is found between the numerical computations and the experimental observations     

Hypadapter: An adaptive hypertext system for exploratory learning and programming

We have developed an adaptive hypertext system designed to individually support exploratory learning and programming activities in the domain of Common Lisp. Endowed with domain-specific knowledge represented in a hyperspace of topics, the system builds up a detailed model of the user's expertise which it utilizes to provide personalized assistance. Unlike other work emerging in the field of adaptive hypertext systems, our approach exploits domain and user modelling techniques to support individuals in different ways. The system not only generates individualized presentations of topic nodes, but also provides adaptive navigational assistance for link-based browsing. By identifying and suggesting useful hyperlinks according to the user's knowledge state and preferences, the system encourages and guides exploration. While browsing through the hyperspace of topics, the system analyses the user's navigational behaviour to infer the user's learning progress and to dynamically adapt presentations of topics and links accordingly.     

Characteristics of Stable Pickering Emulsions under Process Conditions

Emulsions stabilized by solid particles are so called Pickering emulsions which are characterized by their high stability against coalescence. This type of emulsion can be used for a lot of applications. Very little is known about how reaction conditions affect their properties. In this study the influence of important reaction conditions like shear stress, pressure, temperature, and the influence of synthesis gas on Pickering emulsions is investigated. It is shown that the emulsions remain stable in terms of coalescence in a broad range of the reaction conditions and are suitable as reaction media for industrial processes and for a reaction optimization with a subsequent separation step.     

Tuning Pickering Emulsions for Optimal Reaction and Filtration Conditions

The use of Pickering emulsions has recently received increased attention in catalyzed multiphase reactions. Here, the ultrafiltration of Pickering emulsions is studied for product separation and to retain the catalyst in the reactor. To find the optimum between a high specific surface area for high reaction rates and a suited drop size distribution for high permeate fluxes, the preparation method of Pickering emulsion was investigated. It was found that the stability of the emulsion during filtration does not only depend on the solid particle content, but also on the drop size distribution.     

Genetically Encoded Biotin Analogues: Incorporation and Application in Bacterial and Mammalian Cells

The biotin–streptavidin interaction is among the strongest known in nature. Herein, the site-directed incorporation of biotin and 2-iminobiotin composed of noncanonical amino acids (ncAAs) into proteins is reported. 2-Iminobiotin lysine was employed for protein purification based on the pH-dependent dissociation constant to streptavidin. By using the high-affinity binding of biotin lysine, the bacterial protein RecA could be specifically isolated and its interaction partners analyzed. Furthermore, the biotinylation approach was successfully transferred to mammalian cells. Stringent control over the biotinylation site and the tunable affinity between ncAAs and streptavidin of the different biotin analogues make this approach an attractive tool for protein interaction studies, protein immobilization, and the generation of well-defined protein–drug conjugates.     

Dihydroergotamine and heparin or heparin alone for the prevention of postoperative thromboembolism in gynecology

Lens epithelial cells from rats aged 5 days were grown in long-term cultures. These cells age, differentiate and transform spontaneously. Morphological observations indicate five different stages (A-E). The epithelial character is lost after the first two passages. Elongated cells appearing afterwards are considered as cells that have started differentiation to fiberlike cells. Big flattened cells are considered as senescent cells that have lost theie proliferative capacity. Data from population kinetics also reflect these five stages. Chromosome analysis shows that three of the five stages are no longer diploid. Two alternative modes of spontaneous transformation are possible. The proliferative capacity of rat lens epithelial cells is higher than that of rat embryonic fibroblast systems.     

Adenosine, inosine, and guanosine protect glial cells during glucose deprivation and mitochondrial inhibition: correlation between protection and ATP preservation

The purpose of this study was to determine the mechanism by which adenosine, inosine, and guanosine delay cell death in glial cells (ROC-1) that are subjected to glucose deprivation and mitochondrial respiratory chain inhibition with amobarbital (GDMI). ROC-1 cells are hybrid cells formed by fusion of a rat oligodendrocyte and a rat C6 glioma cell. Under GDMI, ATP was depleted rapidly from ROC-1 cells, followed on a much larger time scale by a loss of cell viability. Restoration of ATP synthesis during this interlude between ATP depletion and cell death prevented further loss of viability. Moreover, the addition of adenosine, inosine, or guanosine immediately before the amobarbital retarded the decline in ATP and preserved cell viability. The protective effects on ATP and viability were dependent on nucleoside concentration between 50 and 1,500 microM. Furthermore, protection required nucleoside transport into the cell and the continued presence of nucleoside during GDMI. A significant positive correlation between ATP content at 16 min and cell viability at 350 min after the onset of GDMI was established (r = 0.98). Modest increases in cellular lactate levels were observed during GDMI (1.2 nmol/mg/min lactate produced); however, incubation with 1,500 microM inosine or guanosine increased lactate accumulation sixfold. The protective effects of inosine and guanosine on cell viability and ATP were >90% blocked after treatment with 50 microM BCX-34, a nucleoside phosphorylase inhibitor. Accordingly, lactate levels also were lower in BCX-34-treated cells incubated with inosine or guanosine. We conclude that under GDMI, the ribose moiety of inosine and guanosine is converted to phosphorylated glycolytic intermediates via the pentose phosphate pathway, and its subsequent catabolism in glycolysis provides the ATP necessary for maintaining plasmalemmal integrity.     

Decision rule-based approach to automatic tree crown detection and size classification

The goal of this study was to develop a decision rule heuristic that would incorporate theories of forest stand dynamics and crown competition into an automatic crown detection and crown size search algorithm. Specifically, we sought to develop new multi-dimensional template matching methods fused with knowledge-based decision rules that model spatial considerations for crown competition and develop multi-scale assessment criteria for appraisal of crown detection and crown size at the stand, local neighbourhood and individual crown levels. The decision rule approach to crown detection and crown size was tested on a mature mixed coniferous and deciduous forest typical of southern New England, USA. Multi-dimensional template matching was applied to a high resolution (30 cm per pixel side) colour infrared image of the study site. The decision rule heuristic developed for this study effectively reduced 2626 potential crown detections to 568 crowns, producing a 91% rate of crown detection when compared with the 516 field-measured crowns. The automatically derived crown size class distribution was shown to be statistically similar to the distribution of field crown size classes using the Kolomogorov–Smirnov statistic. Finally, a fuzzification of classification assignments to crown classes either one above or below actual crown size class resulted in an 80% match between individual field crowns and remotely sensed crowns within a 6 m spatial lag.