Kinetics of nitric acid leaching of low-grade rare earth elements from phosphogypsum

Phosphogypsum(PG)is a potential resource for rare earth elements(REEs).Several studies have been carried out on REE leaching from PG.However,few in-depth studies have investigated the kinetics of this leaching process.In this study,the leaching kinetics of REEs from PG in nitric acid at different temperatures were explored in depth.The experiments show that the maximum leaching recovery for ΣREE was 58.5%,75.9%and 83.4%at 30,60 and 80℃,respectively.Additionally,among La,Ce,Y and Nd,Y had the highest leaching rate.A new shrinking core model(SCM)based on the dissolution reaction of a cylindrical solid particle with interfacial transfer and diffusion across the product layer as the rate-controlling step was deduced and could well fit the leaching process of REEs from PG.The activation energies for the leaching of La,Ce,Y and Nd were determined on the basis of the new cylindrical SCM.In summary,the cylindrical SCM was a more suitable fitting model than the spherical SCM,and the interfacial transfer and diffusion across the product layer were the rate-controlling step for REE leaching from the PG sample.

基于癌症基因组图谱数据库结直肠癌免疫细胞浸润预测模型的建立

目的:研究结直肠癌组织的免疫细胞浸润与临床预后之间的相关性。方法:从癌症基因组图谱(the can-cer genome atlas,TCGA)中提取结直肠癌数据,基于反卷积算法(CIBERSORT)分析评估结直肠癌组织中22种肿瘤浸润性免疫细胞(tumor-infiltrating immune cells,TIICs)的浸润模式,以确定不同TIICs表达程度与5年生存率之间的关联。使用条形图展示结直肠癌样本中TIICs比例,绘制矩阵图分析不同TIICs之间的相关性。结果:共从TCGA数据库中提取了473例结直肠癌组织和41个正常对照组织,对比分析表明,结直肠癌组织中各种TIICs比例存在差异。在研究的细胞亚群中,结直肠癌组织中M0、M1和M2巨噬细胞和单核细胞的比例相对较高,而B细胞和中性粒细胞的比例相对较低。TIICs的比例与患者的TNM分期及临床分级显著相关:静息NK细胞、CD8+T细胞、浆细胞与T期相关,活化树突状细胞与N期相关,嗜酸性粒细胞、M1巨噬细胞及活化肥大细胞与M期相关,M1巨噬细胞和单核细胞与临床分级相关。生存分析结果显示,活化的树突状细胞与结直肠癌患者的5年生存率呈正相关,幼稚CD4+T细胞与5年生存率呈负相关。结论:分析结直肠癌患者肿瘤组织TIICs亚群比例具有潜在的临床预后价值,可通过其识别可能从化疗中受益的患者,并预测新药的可能靶点。