Cooperative Structure-Directing Effects in the Synthesis of a High-Silica Zeolite Mazzite Analogue

A zeolite Mazzite (MAZ) analogue with high silica content has been synthesized from a Na2O-Al2O3-SiO2-morpholine-H2O system. The crystal morphology of this MAZ analogue was found to consist of spherical agglomerates of diameter up to 17 μm. It has been unequivocally demonstrated that zeolite Mordenite (MOR) or amorphous material was produced instead in the absence of either morpholine or Na+. Associated phases indicate that the MAZ may be a “intermediate phase” between the crystallization fields of zeolites Analcime (ANA) and MOR. Thus, the zeolite MAZ analogue is seemingly derived from the cooperative structure-directing effect of the organic molecule morpholine and the inorganic cation Na+. The results of CHN elemental analyses as well as of thermogravimetric (TG) analyses confirmed that morpholine had been incorporated into the zeolitic structure.

单域抗体的研究和应用进展

传统IgG抗体分子一般由轻链和重链组成,轻链包含1个可变区(VL)和1个恒定区(CL),重链包含1个可变区(VH)和3个恒定区(CH1,CH2,CH3)。单域抗体(Single domain antibody,sdAb),是指缺失抗体轻链而只有重链可变区的一类抗体,因其分子量小,也被称为纳米抗体(Nanobody)。20世纪90年代,单域抗体最早在骆驼科动物中被发现,之后在护士鲨、大星鲨和鳐鱼等软骨鱼纲动物中也发现了类似的抗体。单域抗体虽然结构简单,但仍然可以达到与传统抗体相当甚至更高的与特异抗原结合的亲和力。相比于传统抗体,单域抗体具有分子量小、稳定性强、易于重组表达等优点。近年来在生物学基础研究和医学临床应用方面均备受关注并被广泛应用。文中将从单域抗体的结构特征、理化性质、筛选方法及其在生物医学领域的重要应用进展进行综述。