Lipasekatalysierte Triglyceridumesterung in einem lösungsmittelfreien Prozeß I: Analytik und Umesterungskinetik

Lipase-Catalyzed Interesterification of Triglycerides in a Solvent-Free Process I: Analytics and Kinetics of the Interesterification The interesterification of lipids catalyzed by immobilized lipases is an interesting substitute to the chemical interesterification. Studies using an industrial manufactured biocatalyst in a solvent-free process were performed. The kinetics of the interesterification were examined as a function of temperature and water content of the reaction system. The reaction rate of the interesterification can be described with reversible first order reaction kinetics. A part of the triglycerides of the substrate is hydrolyzed by a lipasecatalyzed lipolysis. Hydrolysis products are 1,2(2,3) and 1,3-diglycerides. This shows that an unspecific interesterification is catalyzed if the residence time is extended.     

Characterization of in Vitro Transdermal Iontophoretic Delivery of Insulin

In-vitro studies were conducted to characterize the transdermal iontophoretic delivery of insulin, thus avoiding potential complications from various biological variations, which may be encountered during in-vivo studies. The proteolytic degradation of insulin in skin homogenates and degradation under the experimental conditions used was investigated. Appropriate adjuvants were incorporated to minimize the potential degradation problems of insulin. ¹²⁵I-Insulin was observed to penetrate into and accumulate in the skin during the iontophoresis period. It was then released gradually from this depot, as a mixture of intact and ¹²⁵-I labelled fragments, into the receptor medium. Drug desorption studies supported the theory of skin depot or reservoir formation. It was found that an electric field could be used to facilitate the desorption of drug from the depot. The post-application flux of insulin (or its fragments) from the skin depot formed during iontophoresis was monitored to study the factors affecting the iontophoretic delivery of insulin. Stripping and delipidization of the skin were noted to increase the skin permeation rate of insulin. The cumulative radioactivity permeated and accumulated in the skin was higher at pH 3.6 than at pH 7.4. The iontophoresis-facilitated transdermal delivery was observed to increase with increasing duration of current application and increasing donor concentration of insulin. Modulation of drug delivery by multiple applications was also found to be feasible.     

A method for efficiently executing horn clause programs using multiple processors

Previous investigations have suggested the use of multiple communicating processors for executing logic programs. However, this strategy lacks efficiency due to competition for memory and communication bandwidth, and this is a problem that has been largely neglected. In this paper we propose a realistic model for executing logic programs with low overhead on multiple processors. Our proposal does not involve shared memory or copying computation state between processors. The model organises computations over the nondeterministic proof tree so that different processors explore unique deterministic computation paths independently, in order to exploit the “OR-parallelism” present in a program. We discuss the advantages of this approach over previous ones, and suggest control strategies for making it effective in practice.     

A new approach to digital current differential protection for lowand medium voltage feeder circuits using a digital voice-frequency gradecommunications channel

A new approach to digital current differential protection is described which provides the capabilities of conventional pilot wire differential protection while using the limited data transfer capabilities of a digital data voice-frequency grade communications channel. This approach compares polyphase polarised current measurements taken at the feeder's terminals to detect faults and can trip in under two power system cycles. The algorithms decouple the measurements from the power system frequency and its waveform, and thereby have a high inherent tolerance to the complications introduced by communication channel delays and their fluctuations. For this project, the communications requirements have been limited to a full duplex 2400 bits/sec system suitable for operation over a voice-frequency grade channel     

All-optical 1.5 μm to 1.3 μm wavelength conversion in awalk-off compensating nonlinear optical loop mirror

We demonstrate highly efficient all-optical conversion from 1.5 μm to 1.3 μm using a novel nonlinear optical loop mirror that compensates for walk-off. We make the fiber loop by splicing alternating segments of standard single-mode and dispersion-shifted fibers and choose their lengths such that the walk-off of the 1.3 μm and 1.5 μm pulses in one segment is completely reversed in the adjacent segment. We also show that the width of the converted pulses can be tailored by this scheme     

Redefinitions of the science-practice relationship without a framework for unity will fail.

Comments on L. T. Hoshmand and D. E. Polkinghorne's (see record 1992-21300-001) article on redefining the science–practice relationship. Contrary to Hoshmand and Polkinghorne's position, it is suggested that the common-sense language of practice needs to be connected to the systematic language of the relevant basic science. Important activities in psychology are currently separated because the connections have not yet been established, not because they are incommensurate. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Has psychology ever been a science of behavior? A comment on Skinner.

Argues that B. F. Skinner (see record 1988-00027-001) failed to recognize the role of behaviorism in the failure of psychology to become a science of behavior. The authors state that behaviorism has generated laws concerning the impact of behavior on certain environments instead of laws of behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Chromium in Austrian foods

The chromium content in foods is relatively low and the most foods have a content below 0.1 ppm. Only spices, cacao, cacao products, poppy and whole meal products contain higher contents. The often published high chromium content of corn germ oil could not be verified. We did not find any chromium enrichment in the entrails of a cow. In addition the chromium contents of each food are strong deviated. The analysed values were sometimes lower than in literature. We expect that the elder values are higher because of different contaminations in some cases.     

Modeling of polypropylene degradation during reactive extrusion with implications for process control

This paper presents the development of a model for free radical initiated polypropylene degradation during reactive extrusion that combines a kinetic model of the polypropylene degradation reaction with a simplified model of the melting mechanism in the extruder. The free radical initiated degradation of polypropylene is characterized by a narrowing of the molecular weight distribution (MWD) and a decrease in the molecular weight averages. A high temperature SEC is used to determine MWD's for three different commercially available polypropylenes degraded at various initiator concentrations in a 1.5 inch single screw extruder (L/D = 24:1). The predictions of the kinetic model alone and the combined kinetic-melting model are compared with the experimentally determined MWD's and molecular weight averages for the degraded polypropylenes. The predictions of a modified kinetic model that includes the possibility of termination by combination are also examined. The kinetic-melting model is found to provide significantly improved predictions of the experimentally determined MWD's and molecular weight averages in comparison to the original kinetic model. A viscosity-molecular weight relationship is also developed, which is then used to determine the gain of the degradation process as a function of the initiator concentration from the molecular weight averages predicted by the kinetic-melting model. Earlier work has shown such prior knowledge of the process gain can be used to significantly improve the performance of process control schemes for the degradation process.