Function of Graphene Oxide as the “Nanoquencher” for Hg2+ Detection Using an Exonuclease I-Assisted Biosensor

Graphene oxide is well known for its excellent fluorescence quenching ability. In this study, positively charged graphene oxide (pGO25000) was developed as a fluorescence quencher that is water-soluble and synthesized by grafting polyetherimide onto graphene oxide nanosheets by a carbodiimide reaction. Compared to graphene oxide, the fluorescence quenching ability of pGO25000 is significantly improved by the increase in the affinity between pGO25000 and the DNA strand, which is introduced by the additional electrostatic interaction. The FAM-labeled single-stranded DNA probe can be almost completely quenched at concentrations of pGO25000 as low as 0.1 μg/mL. A simple and novel FAM-labeled single-stranded DNA sensor was designed for Hg²⁺ detection to take advantage of exonuclease I-triggered single-stranded DNA hydrolysis, and pGO25000 acted as a fluorescence quencher. The FAM-labeled single-stranded DNA probe is present as a hairpin structure by the formation of T–Hg²⁺–T when Hg²⁺ is present, and no fluorescence is observed. It is digested by exonuclease I without Hg²⁺, and fluorescence is recovered. The fluorescence intensity of the proposed biosensor was positively correlated with the Hg²⁺ concentration in the range of 0–250 nM (R² = 0.9955), with a seasonable limit of detection (3σ) cal. 3.93 nM. It was successfully applied to real samples of pond water for Hg²⁺ detection, obtaining a recovery rate from 99.6% to 101.1%.     

长螺旋压灌扩底桩新施工工艺特点及工程优势浅析

普通钻孔灌注桩在施工过程中常造成倾斜过大、断桩、偏移、钻孔偏斜、桩承载力低、颈缩、孔壁坍塌和孔底沉渣等工程问题。通过对普通钻孔灌注桩施工工艺和长螺旋压灌扩底桩新施工工艺进行对比分析,对长螺旋压灌扩底桩的同步技术、振捣插筋逆作法、特制扩底钻头扩底技术、钻孔成桩一体化和压力灌注进行阐述,总结出长螺旋压灌扩底桩新施工工艺应用于工程中具有成桩质量好、经济性好、单桩承载力高、施工效率高和适用性好等工程优势。     

国内外能源利用效率比较及对我国的启示

经济增长与能源消耗之间有着密切的关系。通过对快速增长的新兴经济体以及经历类似阶段的发达国家的能源利用效率的比较和政策的分析,指出我国能源问题的原因在于生活、建筑能耗方面及高耗能行业的过度消耗,进而提出规范市场、优化产业结构等政策建议,从而实现使经济发展走上资源节约型、环境友好型的良性循环这一目标。     

大安山煤矿轴13顺槽沿空留巷锚杆支护技术研究

通过对大安山煤矿轴部锚杆支护技术方案的分析、设计、施工和现场监测,确定了大安山轴13槽锚杆支护的合理参数,并取得了良好的经济和社会效益.     

水库移民经济风险及其防范和规避对策研究

水库移民是由于水电工程建设需要征用土地而引起的非自愿移民,涉及到区域性的人口大规模迁移与社会系统的重建.由于长期以来形成的重工程、轻移民思想束缚,导致水库移民面临各种经济风险.对水库移民经济风险进行科学分析,研究其产生原因,并有针对性地提出防范和规避各种经济风险的措施,为地方移民工作提出合理化建议,以保障水库移民的顺利进行.     

检测实验室质量改进及统计技术的运用

探讨了在检测实验室中开展检测过程质量改进活动,以及在此过程中统计技术的运用.     

Differential MicroRNA Expression in Porcine Endometrium Related to Spontaneous Embryo Loss during Early Pregnancy

Litter size is an important indicator to measure the production capacity of commercial pigs. Spontaneous embryo loss is an essential factor in determining sow litter size. In early pregnancy, spontaneous embryo loss in porcine is as high as 20–30% during embryo implantation. However, the specific molecular mechanism underlying spontaneous embryo loss at the end of embryo implantation remains unknown. Therefore, we comprehensively used small RNA sequencing technology, bioinformatics analysis, and molecular experiments to determine the microRNA (miRNA) expression profile in the healthy and arresting embryo implantation site of porcine endometrium on day of gestation (DG) 28. A total of 464 miRNAs were identified in arresting endometrium (AE) and healthy endometrium (HE), and 139 differentially expressed miRNAs (DEMs) were screened. We combined the mRNA sequencing dataset from the SRA database to predict the target genes of these miRNAs. A quantitative real-time PCR assay identified the expression levels of miRNAs and mRNAs. Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway enrichment analyses were performed on differentially expressed target genes of DEMs, mainly enriched in epithelial development and amino acids metabolism-related pathways. We performed fluorescence in situ hybridization (FISH) and the dual-luciferase report gene assay to confirm miRNA and predicted target gene binding. miR-205 may inhibit its expression by combining 3′-untranslated regions (3′ UTR) of tubulointerstitial nephritis antigen-like 1 (TINAGL1). The resulting inhibition of angiogenesis in the maternal endometrium ultimately leads to the formation of arresting embryos during the implantation period. This study provides a reference for the effect of miRNA on the successful implantation of pig embryos in early gestation.     

负载氯喹的骨靶向纳米颗粒打破肿瘤细胞增殖与骨吸收之间的恶性循环

肿瘤细胞增殖与骨吸收之间的恶性循环加剧了骨肿瘤的进展和转移风险.为此,我们设计并制备了聚乙二醇-阿仑膦酸钠修饰的聚多巴胺(PPA)纳米粒子,并在其表面负载自噬抑制剂氯喹(CQ),期望利用该治疗载体(PPA/CQ)打破肿瘤细胞增殖与骨吸收之间的恶性循环,从而有效地治疗骨肿瘤.实验证明,PPA/CQ可以有效地富集到骨组织,...     

基于Moodle和PhoneGap的移动学习客户端的设计与应用研究

本文将结合用户移动学习现状及偏好,确定移动学习客户端的系统需求,进而基于Moodle和PhoneGap平台,实现对移动学习客户端的设计,并将移动学习客户端应用到实际教学过程中,确定应用成效。