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  • 1995-1999  (4)
  • Expert system  (2)
  • Sarcoplasmic reticulum  (2)
  • 1
    ISSN: 1432-2013
    Keywords: Key words Heart muscle ; Extracellular [Ca2+] ; Intracellular [Ca2+] ; Sarcoplasmic reticulum ; Ca-uptake
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  Rat ventricular trabeculae were mounted for isometric tension recording, and then permeabilized with saponin. The Ca2+ concentration ([Ca2+]) within the permeabilized preparation (cytosolic [Ca2+]) was monitored continuously using Indo-1 and the integrals of Ca2+ transients resulting from brief caffeine application used as an index of the sarcoplasmic reticulum (SR) Ca2+ content. The relationship between SR Ca2+ content and cytosolic [Ca2+] was studied within the reported physiological range (i.e. 50–250 nmol · l–1 Ca2+). Increasing cytosolic [Ca2+] from 50 nmol · l–1 to 250 nmol · l–1 increased the steady-state SR Ca2+ content about threefold. However, increasing [Ca2+] above 250 nmol · l–1 typically resulted in spontaneous SR Ca2+ release, with no further increase in SR Ca2+ content. The SR Ca2+ content increased only slowly when cytosolic [Ca2+] was increased; it was unchanged 20 s after a rapid increase in cytosolic [Ca2+], but increased progressively to a new steady-state level during the following 1–2 min. In a parallel series of experiments using intact papillary muscles, increasing extracellular [Ca2+] (from 0.5 to 5 mmol · l–1) significantly increased twitch tension within 20 s of the solution change. These results support previous suggestions that the SR Ca2+ content may increase when diastolic cytosolic [Ca2+] rises during inotropic interventions such as increased stimulus rate or extracellular [Ca2+]. However, the rate at which SR Ca2+ responds to changes in cytoplasmic [Ca2+] within the diastolic range does not appear rapid enough to explain the early potentiation of twitch tension in intact preparations after an increase in extracellular [Ca2+].
    Type of Medium: Electronic Resource
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  • 2
    Electronic Resource
    Electronic Resource
    Springer
    Pflügers Archiv 437 (1998), S. 139-148 
    ISSN: 1432-2013
    Keywords: Key words Ca2+ ; Ca2+ -ATPase ; Caffeine ; Cardiac ; Heart ; Ryanodine ; Sarcoplasmic reticulum
    Source: Springer Online Journal Archives 1860-2000
    Topics: Medicine
    Notes: Abstract  This study was designed to measure the Ca2+ content of rat cardiac sarcoplasmic reticulum (SR) after equilibration with normal diastolic levels of Ca2+ (100 nM), in the absence and presence of caffeine. Measurements of [Ca2+] based on Fura-2 fluorescence were made from a limited bath volume (230 nl) containing individual saponin-permeabilised rat cardiac trabeculae. Injection of caffeine (5–40 mM) into this volume caused an initial release of Ca2+ from the SR, but within 30 s the SR was able to re-accumulate a significant proportion of the Ca2+. Ca2+ re-accumulation into the SR could be prevented by removal of ATP to inhibit the SR Ca2+ pump. Incubation of the preparation in an ATP-containing solution containing caffeine (5–40 mM) and 100 nM Ca2+ indicated that the SR’s ability to retain Ca2+ depends inversely on the dose of caffeine. The relative Ca2+ content of the SR after preincubation with caffeine was 86.7±3.5% at a caffeine concentration of 5 mM, 62.5±5.1% at 10 mM caffeine, 37.8±8.1% at 20 mM caffeine and 7.1±1.9% at 40 mM caffeine. Measurement of the SR Ca2+ release in the presence of different BAPTA concentrations was used to calculate (1) the Ca2+-binding capacity of the preparation (equivalent to 245±10 µM BAPTA) and (2) the Ca2+ content of the SR accessed by caffeine after equilibration with 100 nM Ca2+ (186±11 µmol/l cell volume or 5.6 mmol/l SR volume).
    Type of Medium: Electronic Resource
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  • 3
    Electronic Resource
    Electronic Resource
    Springer
    The international journal of advanced manufacturing technology 14 (1998), S. 350-357 
    ISSN: 1433-3015
    Keywords: Blackboard architecture ; Case-based reasoning ; Expert system ; Process design of injection moulding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract Process design of injection moulding involves the selection of the injection moulding machine, mould design, production scheduling, cost estimation, and determination of injection moulding parameters. An expert system approach has been used to derive the process solution for injection moulding over the past few years. However, this approach is found to be incapable of determining the injection moulding parameters owing to the fragile nature of the knowledge for setting the moulding parameters. In addition, the existing expert systems for process design lack proper architecture for organising heterogeneous knowledge sources. In this paper, the combination of a blackboard-based expert system and a case-based reasoning approach is introduced to eliminate the deficiency of the existing expert-system approach to process design, from which a computational system for the process design of injection moulding, named CSPD, has been developed. CSPD first derives the process solution including the selection of the injection moulding machine and the mould base, tooling cost, processing cost estimation, and production scheduling based on the blackboard-based expert-system approach. It is then followed by the determination of the injection moulding parameters based on the case-based reasoning approach and the previously derived partial solution.
    Type of Medium: Electronic Resource
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  • 4
    Electronic Resource
    Electronic Resource
    Springer
    The international journal of advanced manufacturing technology 14 (1998), S. 239-246 
    ISSN: 1433-3015
    Keywords: Blackboard architecture ; Case-based reasoning ; Expert system ; Process design of injection moulding
    Source: Springer Online Journal Archives 1860-2000
    Topics: Mechanical Engineering, Materials Science, Production Engineering, Mining and Metallurgy, Traffic Engineering, Precision Mechanics
    Notes: Abstract The process design of injection moulding involves the selection of the injection moulding machine, mould design, production scheduling, cost estimation, and determination of injection moulding parameters. Expert system approaches have been attempted to derive the process solution for injection moulding in the past few years. However, this approach has been found to be incapable of determining the injection moulding parameters owing to the difficulty in setting the moulding parameters. In addition, the existing expert systems for process design lack the proper architecture for organising a heterogeneous knowledge source. In this paper, the combination of a blackboard-based expert system and case-based reasoning approach is introduced to make up the deficiencies of the existing expert-system approach to the process design, from which a computational system for process design of injection moulding, named CSPD, was developed and described. CSPD first derives the process solution including the selection of injection moulding machine and mould base, tooling cost, and processing cost estimation, and production scheduling based on the blackboard-based expert-system approach. It is then followed by the determination of the injection moulding parameters based on the case-based reasoning approach and the previously derived partial solution.
    Type of Medium: Electronic Resource
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