Self-repairing functionality and corrosion resistance of in-situ Mg-Al LDH film on Al-alloyed AZ31 surface

A novel Mg-Al LDH film was in-situ prepared hydrothermally in an alkaline aqueous solution on an Al-alloyed AZ31 substrate.The structural,chemical and functional characteristics of the film were explored by means of scanning electron microscope(SEM),X-ray diffraction(XRD),energy dispersive spectrometer(EDS),polarization curve,AC impedance and salt immersion tests,respectively.The anti-corrosion results indicated that the Mg-Al LDH film on the Al-alloyed AZ31 surface could effectively protect the AZ31 from corrosion attack even after 90 days of immersion in 3.5 wt.%NaCl solution.The protection performance is surprisingly better than most of the reported coatings on Mg alloys.More interestingly,when the Mg-Al LDH film was scratched,the exposed Al-alloyed surface might gradually release metal ions and re-generate dense LDH nano-sheets in the corrosive environment to inhibit the further corrosion there,exhibiting a self-repairing behavior.The combination of the benign long-term protection and desirable self-repairing performance in this new process of surface-alloying and LDH-formation may significantly extend the practical application of magnesium alloys.

Rare manifestation of familial vitreous amyloidosis caused by Gly103Arg transthyretin

AIM:To identify and analyze the genotype of the patients with special ocular manifestations of familial vitreous amyloidosis(FVA)in a Chinese Han family.METHODS:Pars plana vitrectomy(PPV)surgery was performed on a 52-year-old Chinese woman presented with vitreous amyloidosis and progressive visual impairment,without evidence of cardiac,renal,gastrointestinal,central nervous system or peripheral nervous system dysfunction.During the surgery,the patient presented with a gray-white dense and thick cotton woollike change in the vitreous body,accompanied by complete retinal detachment.Additionally,hard,free and movable yellow-white deposits were observed in the posterior pole and surrounding retina,the vitreous and subretinal deposits were examined by Congo red staining and immunohistochemical pathological examination,and whole exome sequencing was performed on blood samples from the patient and her cousin.RESULTS:During the operation,it was discovered that there was a complete detachment of the retina and a significant amount of hard,free-floating yellow-white deposits were observed beneath the posterior pole and surrounding retina.This is an exceedingly rare ocular manifestation.Pathological examination of the vitreous and subretinal deposit specimens revealed positive Congo red staining,as well as elevated vascular endothelial growth factor(VEGF)expression in vascular endothelial cells within the sediment specimens upon immunohistochemical examination.The patient and her cousin both exhibited a heterozygous mutation in Glyl03Arg within the transthyretin(TTR)gene,resulting in a substitution of glycine(Gly)at position 103 with arginine(Arg).CONCLUSION:FVA may present with various ocular manifestations,but panretinal detachment is a rare occurrence.In cases where retinal detachment persists for an extended period of time,amyloid deposits may form under the retina through retinal tears,leading to subretinal deposits that can impede retinal reattachment and negatively impact visual prognosis.Elevated levels of VEGF in the eyes of FVA patients may indicate an overexpression state,necessitating careful postoperative follow-up.The heterozygous mutation Gly103Arg may represent a unique pathogenic site in Chinese individuals.

基于可牺牲中间层制备大规模、可控双金属氢氧化物膜的协同策略

层状双金属氢氧化物(LDHs)作为一种类水滑石薄膜,以其优异的特性在许多领域中具有广泛的应用.然而,现有的LDH膜制备路线具有大规模生长受限和不可控等问题.本文中,我们受一种草本植物“落地生根”(Bryophyllum Pinnatum)具有肆意生长特性的启发,首次引入可牺牲的共溅射锌-铝中间层作为“植物种子”,通过“局部溶解”和“溶液渗透”的结构转化机制在任意形状、大小及材质的基底材料上实现大规模、厚度可控的LDH膜制备.通过调控中间膜的成分、结构和表面形貌,设计具有不同特性的LDH转化膜.实验结果表明,所制备的LDH膜具有较大的厚度和多级微观结构的特性,在严苛的磨损条件下仍能实现良好的机械稳定性.另外,我们设计了一系列基于锌-铝单金属中间层的电偶模拟实验对LDH膜的化学转化机理进行了深入探究,解决了传统复杂水热过程中实时监测困难的问题.本工作不仅开发了一种制备具有多尺度特性的LDH转化膜的新策略,同时揭示了复杂的LDH原位转化机理,为拓宽LDH材料在先进智能材料上的实际应用提供了新的发展思路.