Numerical simulations are carried out to investigate the crystallization process of a protein macromolecular substance under two different conditions: pure diffusive regime and microgravity conditions present on space laboratories. The configuration under investigation consists of a protein reactor and a salt chamber separated by an "interface". The interface is strictly related to the presence of agarose gel in one of the two chambers. Sedimentation and convection under normal gravity conditions are prevented by the use of gel in the protein chamber (pure diffusive regime). Under microgravity conditions periodic time-dependent accelerations (g-jitter) are taken into account. Novel mathematical models are introduced to simulate the complex phenomena related to protein nucleation and further precipitation (or resolution) according to the concentration distribution and in particular to simulate the motion of the crystals due to g-litter in the microgravity environment. The numerical results show that gellified lysozyme (crystals "locked"on the matrix of agarose gel) precipitates to produce "spaced deposits". The crystal formation results modulated in time and in space (Liesegang patterns), due to the non-linear interplay among transport, crystal nucleation and growth. The propagation of the nucleation front is characterized by a wave-like behavior. In microgravity conditions (without gel), g-jitter effects act modifying the phenomena with respect to the on ground gellified configuration. The role played by the direction of the applied sinusoidal acceleration with respect to the imposed concentration gradient (parallel or perpendicular) is investigated. It has a strong influence on the dynamic behaviour of the depletion zones and on the spatial distribution of the crystals. Accordingly the possibility to obtain better crystals for diffraction analyses is discussed.

中文翻译：

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g抖动引起的对流干扰对溶菌酶周期性沉淀的影响。

进行了数值模拟，以研究蛋白质大分子物质在两种不同条件下的结晶过程：纯扩散条件和空间实验室中存在的微重力条件。研究中的配置包括一个蛋白质反应器和一个被“界面”隔开的盐室。该界面与两个腔室之一中琼脂糖凝胶的存在严格相关。通过在蛋白室中使用凝胶（纯扩散方案）可防止在正常重力条件下发生沉淀和对流。在微重力条件下，需要考虑与时间有关的周期性加速度（g抖动）。引入了新的数学模型，以根据浓度分布模拟与蛋白质成核和进一步沉淀（或分辨率）有关的复杂现象，特别是模拟由于微重力环境中的g碎屑引起的晶体运动。数值结果表明，凝胶化的溶菌酶（晶体“锁定”在琼脂糖凝胶基质上）沉淀，产生“间隔的沉积物”。由于运输，晶体成核和生长之间的非线性相互作用，晶体形成的结果在时间和空间上得到了调制（李泽刚模式）。成核锋面的传播以波状行为为特征。在微重力条件下（无凝胶），相对于地面上的胶凝构型，g抖动效应可以改变现象。研究了施加的正弦加速度的方向相对于所施加的浓度梯度（平行或垂直）所起的作用。它对耗尽区的动态行为和晶体的空间分布有很大影响。因此，讨论了获得更好的晶体用于衍射分析的可能性。