Facile Approach for Preparation of Xylan-based Double-network Hydrogels

In this study,xylan-based double-network(DN)hydrogels(xylanbased DN gels)with excellent mechanical properties were prepared using acrylic acid and acrylamide(AM)based on a DN approach.The first layer network was obtained by grafting and crosslinking polyacrylic acid(PAA)molecular chains onto xylan with ammonium persulfate(APS)as the initiator and N,N'-methylenebisacrylamide(MBA)as the crosslinking agent;this network was subsequently immersed into an aqueous AM monomer in the presence of APS and MBA for the preparation of the second layer network.The results showed that the double networks were crosslinked by covalent bonds and that the mechanical properties of the xylan-based DN gels were enhanced.Thus,the xylan-based DN gels exhibited a maximum compression stress of 24.9 MPa.The xylan-based DN gels could also recover 97%of their original height after 15 repeated compression cycles;this indicates that the xylan-based DN gels possessed high resistance to friction and wear.Therefore,the prepared xylan-based DN gels have considerable potential for tissue engineering applications.

超声心动图诊断Carney复合征一例

患者,男性,24岁,因脑梗死于2021年1月就诊四川大学华西医院。入院10个月前患者突发短暂意识丧失,自行缓解后未就医;入院2个月前患者再次发生短暂意识丧失,意识恢复后出现言语困难,记忆力减退,在当地医院行相关检查后,考虑脑梗死,为进一步治疗到四川大学华西医院就诊。