Aims The cardiac ryanodine receptor (RyR) Ca2þ release channel homotetramer harbours 21 potentially redox-sensitive cysteine residues on each subunit and may act as a sensor for reactive oxygen species (ROS), linking ROS homeostasis to the regulation of Ca2þ signalling. In cardiac myocytes, arrayed RyRs or Ca2þ release units are packed in the close proximity of mitochondria, the primary source ...

Calcium sparks in cardiac myocytes are brief, localized calcium releases from the sarcoplasmic reticulum (SR) believed to be caused by locally regenerative calcium-induced calcium release (CICR) via couplons, clusters of ryanodine receptors (RyRs). How such regeneration is terminated is uncertain. We performed numerical simulations of an idealized stochastic model of spark production, assuming ...

This paper reports the results of a study into the effectiveness of the SPARK toolset for showing the absence of run-time errors in safety-critical Ada software. In particular, the toolset is examined to determine how effective it is in finding run-time errors in a SPARK program, and how much of the process of proving freedom from run-time errors can be performed automatically. The study identi...

EGR and excess-air dilution have been investigated in a 1.5 L four cylinders gasoline direct injection (GDI) turbocharged engine equipped with prechamber. The influences of the two different technologies on performance are explored. results show that at 2400 rpm 12 bar, can adopt more aggressive ignition advanced angle to achieve optimal combustion phasing. However, has greater fuel economy tha...

The ef®ciencies of methods employed in solution of building simulation models are considered and compared by means of benchmark testing. Direct comparisons between the Simulation Problem Analysis and Research Kernel (SPARK) and the HVACSIM‡ programs are presented, as are results for SPARK versus conventional and sparse matrix methods. An indirect comparison between SPARK and the IDA program is ...

Most points-to analysis research has been done on different systems by different groups, making it difficult to compare results, and to understand interactions between individual factors each group studied. Furthermore, points-to analysis for Java has been studied much less thoroughly than for C, and the tradeoffs appear very different. We introduce SPARK, a flexible framework for experimenting...

J.M. Lehr, C.E. Baum, W.D. Prather and F.J. Agee High Energy Sources Division, Phillips Laboratory Kirtland AFB, New Mexico 87117 The Air Force is interested in compact ultra-wideband systems which utilize a minimum volume of high pressure gas. These desires lead us to look closely at single channel spark gaps, because both the size and volume of gas, for example, hydrogen, under pressure can b...

Spark-assisted homogeneous charge compression ignition (HCCI) combustion may be a method to improve the operation of HCCI engines. In the current study, the impact of spark assist on the fundamental properties of ignition and combustion was investigated in a single cylinder, optically-accessible research engine. Early port fuel injection and air preheating were used with indolene fuel in the st...