Assessment of atrial septal defect morphology by transthoracic three dimensional echocardiography using standard grey scale and Doppler myocardial imaging techniques: comparison with magnetic resonance imaging and intraoperative findings

The properties of chemically cured and light-cured composite resins were recorded at baseline and at intervals over seven years, while the materials were exposed to controlled storage conditions as well as to various conditions typical of clinical situations. For chemically cured resins in clinical conditions, mechanical properties decreased, and working and setting times increased over four years; if refrigerated (controlled), properties remained constant past seven years. For light-cured resins, test results were constant over the entire seven-year test period regardless of storage conditions. An accelerated aging protocol was developed to allow for the evaluation of the relative storage stability of new and similar materials.     

Human C-peptide. Part I: Radioimmunoassay

Synthetic human C-peptide bearing a Tyrosine group at its amino end is labelled with 125iodine using chloramin T or hydrogen peroxide and lactoperoxidase. The results are compared applying both methods. Antiserum to synthetic human C-peptide (without Tyrosine) which was partially compared to rabbit albumin, is raised in guinea pigs and goats. Goats show to be superior to guinea pigs concerning antibody production. The so-called "hook effect" phenomenon is observed in setting up the standard curves for the radioimmunoassay. Monotonically decreasing standard curves are obtained on dilution of antiserum with a high antibody titer which was produced by repeated immunization in goats. Free C-peptide and C-peptide bound to antiserum are separated with the anxion exchange resin Amberlite. Using this separation technique we excluded unspecific binding of labelled C-peptide to protein fractions in serum of diabetics. The sensitivity of our radioimmunoassay is approx. 0.3 ng C-peptide/ml serum. Intra- and interassay variability are below 10%. Human proinsulin is the only substance found to crossreact with the antiserum.     

Effects of piracetam on the performance of rats in a delayed match-to-position task

The growing use of antibody-based separation methods has paralleled the expansion of immunochemical detection methods in moving beyond the clinical diagnostic field to applications in environmental monitoring. In recent years high-performance immunoaffinity chromatography, which began as a separation technique in biochemical and clinical research, has been adapted for separating and quantifying environmental pollutants. Bioaffinity offers a selective biological basis for separation that can be incorporated into a modular analytical process for more efficient environmental analysis. The use of immunoaffinity chromatography for separation complements the use of immunoassay for detection. A widely used immunochemical detection method for environmental analyses is enzyme immunoassay. The objective of this paper is to review the status of bioaffinity-based analytical procedures for environmental applications and human exposure assessment studies. Environmental methods based on bioaffinity range from mature immunoassays to emerging techniques such as immunosensors and immunoaffinity chromatography procedures for small molecules.     

Pentalithium Ferrite (Li5FeO4) as Highly Active Material for Hydrogen Production in the Chemical Looping Partial Oxidation of Methane

In this work, the pentalithium ferrite was synthetized by solid-state method, and it was characterized by XRD and N₂ adsorption–desorption techniques. Then, H₂ production was obtained through a catalytic conversion process; chemical looping partial oxidation (CLPO) of methane using Li₅FeO₄ as multifunctional material. The catalytic decomposition of methane is an easy way to obtain clean energy, such as hydrogen, but in this process carbon deposition is also possible. The results showed that this material has the ability to convert methane to hydrogen, but it is also capable to donate oxygen atoms from its crystalline network, producing carbon monoxide and/or carbon dioxide, limiting the carbon deposition on the ceramic surface. In addition, it was demonstrated that this lithium-based ceramic produces hydrogen over a wide temperature range (550–900 °C), with a stable hydrogen production for 3 h at 825 °C. Furthermore, it was possible to achieve a cyclic test of methane decomposition with a pre-oxidation process between each cycle obtaining an outstanding increase in hydrogen production from 10% in cycle 1 to ~?100% in the cycle 10. This previous stage not only induces an increase in the decomposition of methane, but also avoids carbon deposition accompanied by the production of both CO_X compounds. Finally, it must be mentioned that Li₅FeO₄ is capable to chemisorb both carbon oxides produced, promoting high purity hydrogen production.

     

Objektorientierung in der Informatikausbildung auf der Basis von Smalltalk

Zusammenfassung   Eine in der Informatikausbildung verwendete Programmiersprache sollte dazu geeignet sein, mit geringem Aufwand Konzepte moderner Softwareentwicklung und Abstraktionstechniken zu vermitteln. Wichtige Kriterien einer geeigneten Sprache sind u. a. Orthogonalit?t der Sprache, Sicherheit, geringer Lernaufwand und – aus Sicht praxisbezogener Ausbildung – hohe Verbreitung sowohl in der akademischen als auch der kommerziellen Welt. Smalltalk erfüllt diese Kriterien in hohem Ma?e. Als erste Programmiersprache eingesetzt, wird die objektorientierte Denkweise von Beginn des Studiums an vermittelt. Modellierungstechniken und Designfragen treten in den Vordergrund, w?hrend sprachtechnische Fragen an Bedeutung verlieren. Smalltalk kann durchg?ngig im gesamten Studium verwendet werden, was einerseits die Sprachvielfalt in der Ausbildung zu vermeiden hilft und andererseits Softwarekonzepte aus unterschiedlichen Bereichen wie Software-Engineering und KI nahtlos zu integrieren gestattet. Hierdurch wird ein Beitrag zur Straffung des Studiums geleistet, was angesichts einer als zunehmend wichtig erachteten st?rkeren Vermittlung von nicht-informatischer Kompetenz im Studium dringend notwendig erscheint. Eingegangen am 05.06.1997, in überarbeiteter Form am 22.10.1997     

Middle and long latency auditory evoked potentials in cat. II. Component distributions and dependence on stimulus factors

The middle (10-50 ms) and long (50-600 ms) latency periods of the auditory evoked potential (AEP) were investigated in muscle-paralyzed, artificially respired cats with respect to two issues: (1) the distribution of components across the skull, and (2) the effects of changing stimulus intensity on component latencies and amplitudes. The distributional data were gathered during a behavioral study in which four behavioral tasks related to classical pupillary conditioning were used to vary attentional and arousal processes. The distributions across the skull surface (averaged across tasks) of 12 peaks and troughs (P10, N13, P17, N22, P31, N41, P55, N70, N100, N140, P260 and N520) and seven principal components derived from the set of waveforms collected during this experiment are reported. Both peak amplitudes and principal component scores were distributed differentially across the skull surface. In the second experiment, acoustic stimulus intensity was varied, and AEPs collected from a vertex and temporal electrode site. In general, increasing stimulus intensity had a stronger influence on the earlier portions of the AEP, where increased amplitude and decreased latency was the rule, than on later ones. The relationships between cat and human AEP components were discussed based on both the data presented in this paper and in previous papers.     

PRACTICAL INCONSISTENCY MANAGEMENT FOR CRITICAL-TASKS DECISION-SUPPORT SYSTEMS

Abstract

In this paper, the problem of logical consistency in critical-tasks decision systems is addressed. It is shown how local search techniques can be used to check the (in)consistency of very large propositional knowledge bases (KBs). Using new heuristic findings. we can now implement efficient forms of diagnostic reasoning in the context of very large ICBs modeling deep models of complex devices and including patterns of default reasoning.     

The limitations and potential of AVHRR GAC data for continental scale fire studies

Global Area Coverage (GAC) data from the Advanced Very High Resolution Radiometer (AVHRR) are available on a daily basis, dating back to July 1981. The AVHRR's 3·55–3·93 μm channel is suitable for detection of terrestrial hot spots, such as bushfires. The long-term archives and global cover make the GAC a potentially valuable data source for large scale fire studies. However, these data are sampled spatially through a combination of line skipping and averaging. This study shows that the sampling affects the sensitivity of GAC for fire detection in relation to ecosystem and season. The GAC are found to provide a reasonable measure of fire activity in grassland and open b'ush savannah, but to perform poorly in the forest margins. Overall at least 79 per cent of fires detected with non-sampled AVHRR data are missed by the GAC. This severely limits the use of GAC data for quantitative fire studies. The GAC does appear to provide a reasonable measure of fire calendar (i.e., variations in fire activity with time) and on a continental scale successfully identifies the main regions of fire activity. The potential of these data for continental scale fire studies is illustrated through the preliminary analysis of 277 GAC mosaics of Africa for the period September 1988 to August 1989.