Stochastic Simulation Of Excitation-contraction Coupling

工作摘要专用的48处理器集群已投入使用并安装了软件。目前正在开发3D模型，包括在所有细胞、空间和时间尺度上的扩散和运输过程。这涉及到完全重新编码蒙特卡罗算法，以将其分层嵌入到处理不同比例的嵌套解算器系列中。同时，我们还构建了两个近似模型。其中一个模型在二维网格上风格化了钙释放单位，似乎能够解释局部钙释放事件令人惊讶的一系列行为。此模型现在已在集群上并行化，允许累积大量事件的统计信息。第二个非随机模型在解释窦房结细胞起搏活动的稳健性和激素调节方面取得了出人意料的成功。

SUMMARY OF WORK The dedicated 48-processor cluster has been commissioned and software installed. Work on development of the 3d model including diffusion and transport processes on all cellular spatial and temporal scales is underway. This involves completely recoding the Monte Carlo algorithm to embed it hierarchically in a nested series of solvers handling different scales. Meanwhile, we have constructed two approximate models. One of these models stylized calcium release units on a two-dimensional grid, and appears able to account for a surprising range of behaviors of local calcium release events. This model has now been parallelized on the cluster, allowing statistics of large numbers of events to be accumulated. A second, non-stochastic model was developed which has been unexpectedly successful in accounting for the robustness and hormonal regulation of the pacemaking activity of sino-atrial node cells.