Sm-Co/α-Fe/Sm-Co三层膜磁性能的微磁学模拟

以微磁学理论为基础,利用OOMMF软件采用三维动力学模型模拟研究了Sm-Co/α-Fe/Sm-Co交换耦合三层膜体系的磁滞回线,并对其磁性能分别与软、硬磁层厚度的关系进行了系统的分析.研究结果表明:只有当软磁层厚度小于其临界尺寸(5 nm)时,磁滞同线近似为矩形,此时三层膜完全耦合;硬磁层的厚度对体系的磁性能也有着密切的关系,而且硬磁层的厚度对体系软磁相的临界尺寸也有着一定的影响,只有在合适的软、硬磁含量比例的情况下才能得到具有最佳磁性能的三层膜.     

In situ encapsulation of laccase in nanofibers by electrospinning for development of enzyme biosensors for chlorophenol monitoring

A biosensor based on Trametes versicolor laccase (Lac) was developed for the determination of phenolic compounds. The biosensor was prepared by in situ electrospinning of a mixture of polyvinyl alcohol (PVA), Lac, PEO-PPO-PEO (F108) and gold nanoparticles (Au NPs), where F108 was used as an enzyme stabilizing additive and Au NPs was used to enhance the conductivity of the biosensor. Laser confocal scanning microscopy and electrochemical impedance spectroscopy proved that the enzyme was successfully encapsulated into the electrospun nanofibers. Under the optimal conditions, the lowest detection limit was found to be 0.04 μM (S/N = 3) for 2,4-DCP and the highest detection limit was found to be 12.10 μM for 4-CP. The sensitivity of the biosensor obtained in the linear range for chlorophenols followed the sequence 2,4-dichlorophenol (2,4-DCP) > 2,4,6-trichlorophenol (2,4,6-TCP) > 4-chlorophenol (4-CP). The sensing performance for chlorophenols was attributed to the suitable electrochemical interface of PVA/F108/Au NPs/Lac, resulting from biocompatibility, a high surface area-to-volume ratio (10.42 m(2) g(-1)) and superior mechanical properties of the electrospun nanofibers. The biosensor exhibited good repeatabilities of 7.6%, 2.8% and 9.0% (R.S.D.) and reproducibilities of 14.9%, 10.4% and 13.7% (R.S.D.) for 4-CP, 2,4-DCP and 2,4,6-TCP, respectively. Lac retained 65.8% of its initial activity after a 30-day storage period.     

Construction of covalent organic framework for catalysis: Pd/COF-LZU1 in Suzuki-Miyaura coupling reaction

Covalent organic frameworks (COFs) are crystalline porous solids with well-defined two- or three-dimensional molecular structures. Although the structural regularity provides this new type of porous material with high potentials in catalysis, no example has been presented so far. Herein, we report the first application of a new COF material, COF-LZU1, for highly efficient catalysis. The easily prepared imine-linked COF-LZU1 possesses a two-dimensional eclipsed layered-sheet structure, making its incorporation with metal ions feasible. Via a simple post-treatment, a Pd(II)-containing COF, Pd/COF-LZU1, was accordingly synthesized, which showed excellent catalytic activity in catalyzing the Suzuki-Miyaura coupling reaction. The superior utility of Pd/COF-LZU1 in catalysis was elucidated by the broad scope of the reactants and the excellent yields (96-98%) of the reaction products, together with the high stability and easy recyclability of the catalyst. We expect that our approach will further boost research on designing and employing functional COF materials for catalysis.     

Aggregation-induced emission of tetraphenylethene derivative as a fluorescence method for probing the assembling/disassembling of amphiphilic molecules

The aggregation-induced emission (AIE) of a 1,2-diphenyl-1,2-di(p-tolyl)ethene (TPE) was explored as a novel fluorescence method for probing the assembling/disassembling of amphiphilic molecules. The fluorescence intensity was able to monitor the formation of micelles and determine the critical micelle concentration (CMC) of surfactants. The temperature-dependent micellization of the pharmaceutically important PEO-PPO-PEO copolymer, Pluronic F127, was further studied by using the TPE fluorescence spectrum intensity. Our results showed good agreement with those reported in the literature by using other methods. The special advantage of the AIE probe method was further explored to determine the assembling/disassembling process of the colored amphiphilic molecule, 1-[4-(3-phenylazophenoxy)butyl]triethylamine bromide (AzoC4), whose CMC value has not previously been described. Since the TPE fluorescence signal mainly comes from the aqueous phase, not from the inside of hydrophobic core, it provides a possible platform to study the CMC of those colored surfactants. Based on the novel fluorescence properties of TPE in the aggregated and dispersed states, one can conclude that the TPE method is a promising method for the determination of the CMC and critical micellization temperature (CMT), particularly having a special advantage to determine the assembling/disassembling process of colored amphiphilic molecules.     

Specifically colorimetric recognition of calcium, strontium, and barium ions using 2-mercaptosuccinic acid-functionalized gold nanoparticles and its use in reliable detection of calcium ion in water

A colorimetric probe based on 2-mercaptosuccinic acid-functionalized gold nanoparticles has been developed to exhibit selectivity towards Ca(2+), Sr(2+), and Ba(2+) ions over other metallic cations under specified conditions and finds its practical application in detecting Ca(2+) levels in water.     

高效液相色谱-电喷雾离子阱串联质谱法检测芥子气经皮肤染毒SD大鼠肺中的DNA加合物

运用高效液相色谱-电喷雾离子阱串联质谱(HPLC-ESI-MS/MS)技术,建立了快速、简单、灵敏的SD大鼠肺中N7-(2-羟乙基硫代乙基)鸟嘌呤(N7-HETEG)的检测方法。以N7-苯甲基鸟嘌呤为内标,用甲醇和水为流动相进行梯度洗脱,正离子模式检测,方法的检出限(信噪比(S/N)≥10)为300 pg/mL,定量限(S/N≥20)为850 pg/mL。在300 pg/mL～1.28 μg/mL的质量浓度范围内,N7-HETEG浓度与N7-HETEG和内标的峰面积比呈良好的线性关系(线性相关系数为0.9929)。高、中、低3个添加水平的日内测定精密度(以相对标准偏差(RSD)计)和日间测定精密度均小于10%(n=7),回收率为100%～132%。对SD大鼠背部皮肤染芥子气,剂量分别为5.5、11、22和45 mg/kg,染毒4 d后检测大鼠肺脏中N7-HETEG的含量。各个不同染毒剂量下,每克组织中分别检测到（0.56±0.16）、（0.67±0.12）、（1.36±0.68）和(5.14±0.92) ng N7-HETEG, N7-HETEG的含量随着染毒剂量的增大而增大,表明N7-HETEG可用作芥子气暴露的体内生物标志物。     

多壁碳纳米管固相萃取净化气相色谱法分析蔬菜中有机氯和拟除虫菊酯农药残留

建立了多壁碳纳米管为吸附剂的固相萃取(SPE)净化、气相色谱-电子捕获检测(GC-ECD)测定蔬菜中6种有机氯和7种拟除虫菊酯农药的方法。采用双柱(HP-50和HP-1色谱柱)双检测器进行定性和定量分析。蔬菜样品采用乙腈提取,多壁碳纳米管SPE柱净化,正己烷溶解上样,丙酮-正己烷(7:3, v/v)洗脱,13种农药中有11种农药的添加回收率高于70%。将该净化方法用于荷兰黄瓜、卷心菜、红圣女果、奶油生菜、紫甘蓝、韭菜、大葱和洋葱等样品的净化,与弗罗里硅土SPE柱相比较,净化效果更好,表明多壁碳纳米管具有较强的吸附去除色素的能力,可以避免色素对测定的干扰。     

基于液相色谱-质谱联用技术的代谢组学方法用于中药通心络和人参对过度疲劳大鼠干预作用的评价

用代谢组学方法评价了中药通心络和人参对过度疲劳大鼠的干预作用.通过构造大鼠过度疲劳模型,并分别用通心络和人参进行干预,采用快速液相色谱-离子阱飞行时间质谱(UFLC-IT-TOF-MS)获取大鼠血浆代谢轮廓,并用正交偏最小二乘法(OPLS)进行多变量统计分析,分别找出用于区分通心络和人参干预组大鼠同正常对照大鼠、过度疲...     

Convenient Synthesis of Terminal Alkynes from anti‐3‐Aryl‐2,3‐dibromopropanoic Acids Using a K2CO3/DMSO System

A convenient, efficient, and generally applicable method was developed for the synthesis of terminal alkynes from anti‐3‐aryl‐2,3‐dibromopropanoic acids in the presence of DMSO and K₂CO₃.     

Synthesis and bioactivity of novel nitric oxide-releasing ursolic acid derivatives

A series of furoxan-based novel nitric oxide-donating ursolic acid(UA) derivatives(7a-f) were synthesized,and their cytotoxic activities against HepG2 cells in vitro were evaluated by MTT method.It was found that 7a-d and 7f showed more potent cytotoxic activities than control 5-fluorouracil and UA.