Toxin production of a Malaysian isolate of the toxic red tide dinoflagellate Pyrodiniun bahamense var. compressum was investigated at various stages of the batch culture growth cycle and under growth ...conditions affected by temperature, salinity, and light intensity variations. In all the experiments conducted, only 5 toxins were ever detected. Neosaxitoxin (NEO) and gonyautoxin V (GTX5) made up 80 mole percent or more of the cellular toxin content and saxitoxin (STX), GTX6 and decarbamoylsaxitoxin (dcSTX) made up the remainder. No gonyautoxins I-IV or C toxins were ever detected. In nutrient-replete batch cultures, toxin content rapidly peaked during early exponential phase and just as rapidly declined prior to the onset of plateau phase. Temperature had a marked effect on toxin content, which increased 3-fold as the temperature decreased from the optimum of 28 degrees C to 22 degrees C. Toxin content was constant at salinities of 24 per thousand or higher, but increased 3-fold at 20 per thousand. Toxin content decreased 2-fold and chlorophyll content increased 3-fold when light intensity was reduced from 90 to 15 microeinsteins m-2 s-1. This accompanied a 30% decrease in growth rate. Toxin composition (mole % individual toxin cell-1) remained constant throughout the course of the nutrient-replete culture and during growth at various salinities, but varied significantly with temperature and light intensity changes. At 22 degrees C, GTX5 was 25 mole % and NEO was 65 mole %, while at 34 degrees C, GTX5 increased to 55 mole % and NEO decreased proportionally to 40 mole %. When light intensity was reduced from 90 to 15 microeinsteins m-2 s-1, NEO decreased from 55 to 38 mole %, while GTX5 increased from 40 to 58 mole %. These data suggest that low light and high temperature both somehow enhance sulfo-transferase activity. In general, toxin content and composition in P. bahamense were both influenced by factors that alter the growth rate of the species
Sectors of Zea mays cobs, with and without kernels were cultured in vitro in the presence and absence of fluridone. Cultured kernels, cob tissue, and embryos developed similarly to those grown in the ...field. Abscisic acid (ABA) levels in the embryos were evaluated by enzyme-linked immunosorbant assay. ABA levels in intact embryos cultured in the presence of fluridone were extremely low and indicate an inhibition of ABA synthesis. ABA levels in isolated cob tissue indicate that ABA can be produced by cob tissue. Sections containing kernels cultured in the presence of fluridone were transferred to medium containing fluridone and ABA. Dormancy was induced in more than 50% of the kernels transferred from 13 to 15 days after pollination, but all of the kernels transferred at 16 days after pollination or later were viviparous. ABA recovered from kernels that were placed in medium containing fluridone and ABA suggest that ABA can be transported through the cob tissue into developing embryos and that ABA is required for induction of dormancy in intact embryos
Prompted by a clinical observation of an increase in hospital admissions for acute myocardial infarction during an influenza outbreak, a study was designed to examine the number of deaths from ...ischaemic heart disease (IHD) at the time of influenza. Deaths from IHD were found to be increased at all ages, and particularly in younger age groups when deaths attributed specifically to acute myocardial infarction are considered. The question of whether influenza could act as a precipitating factor in acute myocardial infarction is discussed, together with a possible mechanism.
Adaptive coded modulation (ACM) is a promising tool for transmission in a fading environment. The main motivation for employing ACM schemes is to improve the spectral efficiency of wireless ...communications. In this paper, we present a method for optimizing the average spectral efficiency of an ACM system. One important result of this work is that only a small number of optimally designed codes is needed to yield throughput close to the Shannon limit.
Statistical Methods for Cancer Studies. Edited by R. G. Cornell. New York and Basel, Marcel Dekker, 1984. 496 p. SFr 167. (Statistics: Textbooks and Monographs, Vol. 51)
A combustion-based analytical method, initially developed by the Southwest Research Institute (SwRI) and referred to as the Constant Volume Combustion Apparatus (CVCA), has been further ...researched/developed by an SwRI licensee (Advanced Engine Technology Ltd.). This R&D has resulted in a diesel fuel Ignition Quality Tester (IQT) that permits rapid and precise determination of the ignition quality of middle distillate and alternative fuels. Its features, such as low fuel volume requirement, complete test automation, and self-diagnosis, make it highly suitable for commercial oil industry and research applications. A preliminary investigation, reported in SAE paper 961182, has shown that the IQT results are highly correlated to the ASTM D-613 cetane number (CN). The objective of this paper is to report on efforts to further refine the original CN model and report on improvements to the IQT fuel injection system. The new model, based on the ASTM D-613 reference fuels, has been validated with over 175 fuel samples, which are Adiesel fuels from conventional, oil-sands and offshore sources. It also included cetane-improved, solvent-based and pilot plant diesel fuels. Experiments were also performed to evaluate both the short term and long term variability/repeatability of the test method and further refine the calibration procedures. This investigation confirmed the potential of the IQT to provide repeatable and precise evaluation of the cetane number for a wide range of middle distillate fuels, with 97% of the samples tested within the quoted ASTM precision limits. Based on the test results, the average repeatability of the IQT test for fuels in the 40 to 56 CN range has been established at 0.40 CN, which compares favourably with ASTM D-613 precision data on repeatability. The present paper provides an overview of the precision data from the AET test laboratory for the proposed alternative test method. In addition, the capabilities/benefits of the IQT apparatus in terms of its potential use in research and refinery applications are discussed.
Archäologische Forschungen in Syrien (4) Kühne, Hartmut; Assaf, Ali Abou; Thalmann, J. P. ...
Archiv für Orientforschung,
01/1989, Volume:
36/37
Journal Article
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