基于二维相关近红外光谱判定牛奶中掺杂的目标物

分别配制含有不同浓度尿素(1～20g.L-1)、葡萄糖(1～20g.L-1)和三聚氰胺(0.01～3g.L-1)的牛奶溶液共120个,采用二维相关近红外光谱对掺杂牛奶进行了快速判别分析。以牛奶中掺杂目标物浓度为外扰,构建二维相关近红外光谱,研究了各掺杂牛奶的二维相关近红外特性,并进行对比、分析。掺杂尿素牛奶在同步图上出现两个较强的自相关峰,分别在4 552,4 648cm-1处;掺杂葡萄糖牛奶,在同步图中出现3个较强的自相关峰,分别在4 456,4 392,4 360cm-1处;而掺杂三聚氰胺牛奶也有两个较强的自相关峰,出现在4 256,4 328cm-1处。结果表明:所提出的方法能实现对含有上述掺杂物牛奶的正确识别,为快速判别牛奶的安全性提供新方法。     

磷掺杂缺陷WS2纳米片诱导的高效析氢性能

通过超声剥离法制备二硫化钨(WS₂)纳米片,将纳米片和红磷(P)混合,用氩气(Ar)等离子体对混合物进行处理,制备了P掺杂缺陷WS₂纳米片。对制备的材料进行电催化析氢(hydrogen evolution reaction,HER)测试,结果表明P掺杂的缺陷WS₂纳米片相对于缺陷WS₂纳米片和WS₂纳米片表现出优越的HER催化活性(较小的过电位和Tafel斜率,优异的稳定性)。密度泛函理论计算结果表明,在WS₂结构中P原子和缺陷结构改善了其电子结构,使其具有更加合适的H⁺吸附能垒和H₂生成动力学性能,从而提高催化活性。     

熔盐法制备氧化锆纳米棒

采用非水解溶胶-凝胶工艺合成氧化锆干凝胶粉,然后将干凝胶粉与熔盐混合制备氧化锆纳米棒。借助DTA-TG、XRD、FE-SEM、TEM等测试手段研究了氧化锆的物相转变过程,探讨了熔盐种类与用量、氟化物的添加等工艺参数对制备氧化锆纳米棒的影响。结果表明：以NaVO₃为熔盐,用量为1：1（熔盐与干凝胶的质量比）,并且在添加氟化钠的条件下能够制备产率高,且沿[010] 方向择优生长的单斜氧化锆纳米棒;氟离子一方面加速了熔盐中Zr⁴⁺离子的传质,促使氧化锆干凝胶粉的溶解,另一方面吸附在氧化锆的高能晶面上抑制该晶面的生长,两者的共同作用促进了大量氧化锆纳米棒的形成。     

小体积液液萃取气相色谱-质谱法测定水体中邻苯二甲酸酯

采用小体积液液萃取气相色谱-质谱(GC-MS)法测定水体中邻苯二甲酸酯,有效地避免了各种空白干扰。该法以正己烷为萃取剂,对6种目标化合物的富集倍数达8～321倍。在0.40～20.0μg/L范围内线性良好,6种邻苯二甲酸酯的检出限在0.01～0.10μg/L范围内,适用于实际水体中低浓度邻苯二甲酸酯的测定。     

高效液相色谱法同时检测4种金线莲黄酮苷元及其在提取工艺评价中的应用

基于高效液相色谱(HPLC)和提取离子流色谱-质谱(EIC-MS),建立了金线莲提取成分定性定量分析及提取效率评价新方法。方法采用20RBAX Ecipse XDB-C18色谱柱,以乙腈-0.03%乙酸水溶液为流动相,采用梯度洗脱,同时分离测定金线莲提取液中芦丁、山奈酚、异鼠李素和槲皮素4种黄酮苷元的含量,经EIC-MS验证,结果可靠。以黄酮提取率为指标,评价酶解-醇提、回流-醇提、搅拌-醇提、超声-醇提、超声-微波-醇提和煎煮6种提取工艺,结果显示,最佳提取工艺为回流-醇提法,提取时间短,醇用量少,总提取率最高,可达14.96mg/g。     

Single and Binary Dye Adsorption of Methylene Blue and Methyl Orange in Alcohol Aqueous Solution via Rice Husk Based Activated Carbon: Kinetics and Equilibrium Studies

The present work was mainly focused on the single and binary adsorption of methylene blue(MB) and methyl orange(MO) from alcohol aqueous solution over rice husk based activated carbon(RHAC). The study of single dye adsorption equilibrium experiments found that the Langmuir adsorption model was consistent with the adsorption behavior of RHAC on MB and MO, indicating that it was a single layer adsorption. The adsorption behavior conformed to the pseudo-second-order kinetic model. The binary dye adsorption experiments showed that the Langmuir-Freundlich model could be applied to describe the adsorption behavior of RHAC on MB and MO. Comparation with the single dye system, the adsorption capacity on the binary dye system was larger, and there was "competitive adsorption" and "synergistic adsorption" effects existed. Meanwhile, the pseudo-second-order kinetic model also fit for the binary dye adsorption behavior.     

DNA Nanotechnology on Live Cell Membranes

Recent developments in DNA nanotechnology have brought various nanoscale structures,devices and functional systems for different applications.As biological barriers with significant functions,cell membranes proide direct interfaces for studying cellular environment and states.So far,DNA nanotechnology engineered on live cell membranes has advanced our fundamental understandings of DNA nanomaterials and facilitated the designs of novel sensing,imaging and therapeutic platforms.In this review,we highlighted strategies and outcomes of using DNA nanotechnology on cell membranes towards various biomedical applications,including biosensing,imaging,cellular function regulations and targeted cancer therapy.Furthermore,we also discussed the challenges and opportunities of DNA nanotechnology on cell membranes towards broader applications.     

卒中后癫痫的静息态脑功能磁共振成像研究

本文探讨了静息态脑功能磁共振成像(rs-fMRI)检查在评价卒中后癫痫患者静息态脑功能改变中的应用价值。选择2017年5月~2019年5月我院收治的80例卒中后癫痫患者作为观察组,另选择同期健康体检者53例作为对照组。两组均完成rs-fMRI检查,采集相关数据,计算并比较两组被试全脑低频振幅(ALFF)值。分别以大脑(小脑)ALFF差异区作为种子区,计算并比较其与小脑(大脑)所有体素之间静息态功能连接(rsFC)。与对照组比较,卒中后癫痫患者右侧楔前叶、左侧额中回的ALFF明显升高,而右侧海马、右侧小脑脚2区、左侧小脑4/5区的ALFF明显降低(P<0.05)。以各大脑ALFF差异区(右侧海马、右侧楔前叶、左侧额中回)作为种子区域,卒中后癫痫患者依次对应在左侧小脑8区、右侧小脑4/5区的rsFC值明显升高(P<0.05);以各小脑ALFF差异区(右侧小脑脚2区、左侧小脑4/5区)作为种子区域,卒中后癫痫患者依次对应在左侧额下回、右侧颞中回的rsFC值明显降低(P<0.05)。结果表明,卒中后癫痫患者大脑和小脑之间多个脑区功能连通性发生改变,rs-fMRI检查可客观评价患者静息态脑功能变化,为患者的临床诊疗及预后评估提供影像学依据。     

生物质水热催化制备重要含氧化学品研究进展

作为唯一可再生、 分布广泛的绿色含碳资源, 生物质的高值化利用尤其是制备高品质含氧化学品日益引起研究者的广泛关注, 其中生物质水热催化制备重要含氧化学品是当前的一个重要研究方向. 本文对生物质经水热催化加氢、 脱水和水解制备多元醇、 5-羟甲基糠醛和乳酸的研究进展进行了系统总结和评述, 分析了催化剂的作用机制和产物生成机理, 并对生物质水热催化的研究前景进行了展望.     

A New 1D Cd(Ⅱ) Coordination Polymer Constructed by 2,2'-H_2biimidazole:[Cd(H_2biim)_2(SO_4)]_n·3nH_2O

A new 1D Cd(II) coordination polymer, [Cd(H2biim)2(SO4)]n·3n H2O(1, H2 biim = 2,2'-H2biimidazole), has been hydrothermally synthesized and characterized by single-crystal X-ray diffraction. It crystallizes in monoclinic, space group P21/c with a = 6.8405(14), b = 17.792(4), c = 14.987(3) A, β = 92.68(3), V = 1822.1(6) A3, Z = 4, C12H18 Cd N8O7S, Mr = 530.80, Dc = 1.935 g/cm3, F(000) = 1064, μ(Mo Ka) = 1.371 mm-1, R = 0.0280 and w R = 0.0617. In 1, adjacent Cd(II) atoms are bridged by sulfate anions in bidentate modes to yield a 1D chain. H2 biim ligands are located on both sides of the chain in chelating bidentate modes. Further, the H2 biim ligands from neighboring chains are paired through π-π interactions to generate a supramolecular layer, which is stabilized by the complicated N–H···O and O–H···O hydrogen bonds. In addition, thermal behavior and luminescent property of 1 have been investigated.