钙不依赖性钙调素结合蛋白的研究进展

钙调素是普遍存在于真核生物细胞中、发挥多种生物学调控作用的信号组分.钙调素不仅在有Ca2+情况下通过与钙依赖性钙调素结合蛋白作用而传递信号,也能在相对无Ca2+条件下直接结合钙不依赖性钙调素结合蛋白而传递信号.综述了无钙离子结合钙调素及钙不依赖性钙调素结合蛋白的结构特性、钙不依赖性钙调素结合蛋白的种类及其可能的生物学作用,这将有助于我们深入认识钙调素介导信号途径的特异性、复杂性和多样性.

无钙氧化铝结合的耐火浇注料干燥过程中的动态透气现象

了解与耐火浇注料脱水现象相关的值是必需的,尤其是透气值,它是控制过程最重要的参数。因透气值经常在室温下获得,因此,不能反映水排除过程中发生的明显的微观结构的变化。对于脱水过程仍不清楚且易发生剥落的以无钙结合剂结合的浇注料配方,这个问题变得更加迫切。这项研究已经从无钙高铝质耐火浇注料试样在700℃以上的干燥过程的动态透气性开始进行。试样在110～1650℃的温度范围内经预处理,以提供浇注料的可逆和不可逆的微观结构变化的信息。结果显示了在接近200℃时透气量的波动和明显下降,它有助于解释此类浇注料出现剥落现象的原因。

Composition and Structural Features of Calcium—Bound and Iron—and Aluminium—Bound Humus in Soils

Calcium-bound and iron-and aluminium-bound humus extracted from different soils collected from north to south of China were characterized by chemical and spectroscopic methods. Meaningful differences in the composition and structure between them were revealed by (13)C NMR, visible spectroscopy and elemental analysis. Results showed that the contents of carbon, hydrogen and nitrogen were higher in iron-and aluminium-bound humus than in calcium-bound humus while oxygen content in calcium-bound humus was shown to be higher. The calcium-bound humus had hasher C/N and O/C ratios than iron- and aluminumbound humus. The calcium-bound humic acid (HA1) showed higher E4/E6 ratios than iron- and aluminumbound humic acid (HA2) while iron- and aluminum-bound pulvic acid (FA2) showed higher E4/E6 ratios than calcium-bound fulvic acid (PA1). An inverse relationship between E4/E6 ratios and aromaticity as determined by (13)C NMR spectra was observed for HA and FA from black soil. The (13)C NMR spectroscopy revealed that HA2 was more aromatic than HA1. On the other hand, FA1 exhibited a higher aromaticitythan FA2.