L-苯丙氨酸衍生物的一锅法合成及其抗/促凝活性

氨基酸及其衍生物在止血/抗凝活性方面有一定的应用。以L-苯丙氨酸为起始原料,经磺化引入磺酸基,再与甲醇、乙醇、丙醇、异丙醇和正丁醇脱水酯化,一锅法合成了6种未见报道的L-苯丙氨酸的磺酸酯类衍生物(L1~L6),以期获得具有的较强血液生理活性的潜在药物。实验中采用了质谱、核磁共振进行结构表征。该合成方法产率高(78%~95%),后处理简单,不失为合成该类衍生物的好方法。衍生物的凝血四项实验表明:抗促凝效果是内源性和外源性凝血途径共同作用的结果。血浆复钙实验表明:衍生物均具有一定的抗凝活性,其抗凝效果随浓度变化而变化,但是随R链的长度增加,抗凝效果并未见规律性。衍生物的抗凝活性主要受磺酸基及酯基的影响,因此在设计合成抗血栓化合物时可以考虑引入磺酸基及酯类基团。     

Photoinduced Magnetization Change in Multiferroic YbFe2O4

We investigate the influence of laser illumination on the magnetization in multiferroic YbFe2O4 single crystals. A photoinduced magnetization change is confirmed in both ab plane and the c-axis directions. The temperature dependence of the photoinduced magnetization reduction excludes laser heating as the cause. In terms of the breakdown of charge order driven by laser illumination, the photoinduced magnetization change provides strong evidence for the spin-charge coupling in YbFe2O4. This photomagnetic effect based on charge-order-induced multiferroicity could be used for the non-thermal optical control of magnetization.     

Coexistence of Quasi-two-dimensional Superconductivity and Tunable Kondo Lattice in a van der Waals Superconductor

Realization of Kondo lattice in superconducting van der Waals materials not only provides a unique opportunity for tuning the Kondo lattice behavior by electrical gating or intercalation, but also is helpful for further understanding the heavy fermion superconductivity. Here we report a low-temperature and vector-magneticfield scanning tunneling microscopy and spectroscopy study on a superconducting compound（4Hb-TaS₂） with alternate stacking of 1T-TaS₂ and 1H-TaS₂     

Modulation of Insulator-Metal Transition Temperature by Visible Light in La7/8Sr1/8MnO3 Thin Film

Effects of magnetic field and light illumination on the electrical transport properties of La7/8Sr1/8MnO3 thin film grown on a Si substrate are investigated. The film shows an insulator-metal transition at Tp - 191.9 K and a low-temperature resistance minimum at Tmin ≈ 48 K in darkness. Both magnetic field and light illumination shift the insulator-metal transition temperature Tp to be higher, while the low-temperature transport properties of the film induced by them show different trends. That is, the magnetic field and light illumination make the Tmin shift to lower and higher temperatures, respectively. The enhancement of both Tp and Train under light illumination could be explained in terms of photoinduced hole-doping and demagnetization effects of La7 /8Sr1/8MnO3.     

在线固相萃取/液相色谱-串联质谱法快速检测全血及尿液中15种杀鼠药

建立了同时测定血液和尿液样品中15种杀鼠药的在线固相萃取/液相色谱-三重四极杆串联质谱(On-line SPE/LC-MS/MS)分析方法。用乙腈沉淀样品中的蛋白质,经稀释、离心、过滤后直接进样。通过在线固相萃取柱HLB富集纯化,以ZORBAX Eclipse Plus C18柱为分析柱,乙腈-0.01 mol/L乙酸铵水溶液为流动相进行梯度洗脱。采用电喷雾电离(ESI+/ESI-)快速正负切换模式,动态多反应监测模式(DMRM)扫描,外标法定量。结果表明,15种杀鼠药采用二次方程拟合时线性关系良好,血液中r~2≥0.997 8,尿液r~2≥0.996 5,方法的检出限和定量下限分别为0.10~5.00μg/L和0.50~10.0μg/L,3个添加水平下的回收率为81.8%~109.6%,日内相对标准偏差(RSD)为0.3%~3.6%,日间RSD为0.3%~3.8%(n=6)。该方法简单方便,灵敏度高,能够用以血液和尿液样品中15种杀鼠药的快速筛查和准确定量。     

L-酪氨酸衍生物的合成及其与人血清白蛋白的相互作用

以L-酪氨酸为原料,分别与邻甲氧基肉桂酸和间甲氧基肉桂酸进行了酰胺化反应,合成了两种L-酪氨酸衍生物(E)-3-(4'-羟基苯基)-2-[3″-(2-甲氧基苯基)丙烯酰胺基]丙酸(I)和(E)-3-(4'-羟基苯基)-2-[3″-(3-甲氧基苯基)丙烯酰胺基]丙酸(II),运用ESI-MS、1H NMR、13C NMR对其结构进行表征确认。通过荧光光谱、紫外可见吸收光谱结合Auto Dock分子对接方法,研究了化合物I和II对人血清白蛋白(HSA)的作用机制。结果表明,I和II对HSA的猝灭机制为静态猝灭,过程中伴随着非辐射能量转移。化合物I和II主要通过疏水作用与HSA的结合,结合过程是自发的。Auto Dock分子对接结果表明化合物I和II与HSA之间主要是疏水作用力,结合位点位于亚结构域IIA形成的疏水腔中,即site I。分子对接结果与光谱实验结果基本一致。     

在线固相萃取-液相色谱-串联质谱法测定血液和尿液中31种有毒植物化学组分的含量

取血液或尿液样品0.20mL,加入乙腈0.60mL,涡旋振荡1min,并离心10min,取上清液0.40mL,加入10mol·L~(-1)乙酸铵溶液(pH 7.0)1.1mL,振荡1min,用0.22μm滤膜过滤后,溶液经HLB在线固相萃取柱富集纯化,所用流动相A为水,B为甲醇,C为乙腈。所得淋出液经Poroshell 120EC-C18色谱柱并用流动相A 10mol·L~(-1)乙酸铵溶液和流动相B乙腈(上述二流动相中均含φ0.1%甲酸)进行梯度洗脱,使所测定的31种有毒植物的化学组分达到分离,并进行质谱测定。所测定的31种目标物的质量浓度在一定范围内与其峰面积之间呈线性关系,其检出限(3S/N)在0.01～5.00μg·L~(-1)之间。分别以上述两种样品为基体,用标准加入法进行回收试验,测得31种化合物在血液样品中的回收率在90.4%～107%之间,在尿液样品中的回收率在90.0%～103%之间。测定值的相对标准偏差(n=6)依次在0.2%～2.6%,0.3%～2.9%之间。     

Different effects of Ce-doping on orbital and spin ordering in perovskite vanadate Sm_(1-χ)Ce_χ VO_3

The effects of Ce-doping on the phase transition of the orbital/spin ordering (OO/SO) are studied through the structural, magnetic, and electrical transport measurements of perovskite vanadate Sm1 x Ce x VO 3 . The measurements of structure show that the cell volume decreases as x≤ 0.05, and then increases as Ce-doping level increases further. The OO state exists but is suppressed progressively in the sample with x≤0.2 and disappears as x0.2. The temperature at which the C-type SO transition is present increases monotonically with Ce-doping level increasing. The temperature dependence of resistivity for each of the samples shows a semiconducting transport behavior and the transport can be well described by the thermal activation model. The activation energy first decreases as x ≤0.2, and then increases for further doping. The obtained results are discussed in terms of the mixed-valent state of the doped-Ce ions.     

二维层状材料FePSe3的高压物性

FePSe₃在高压下会出现半导体到金属的转变、超导电性以及高自旋到低自旋的转变等多种有趣的物理现象，但目前对其在高压下的晶体结构分析仍以理论研究为主，结构的不确定阻碍了对其物理性质的深入研究。为此，利用金刚石对顶砧结合高压拉曼光谱、高压同步辐射X射线衍射以及高压电输运测量，对FePSe₃在高压下的行为进行了研究。结果表明，FePSe₃在低于60.0 GPa的压力范围内经历了3次结构相变，完成了LP—HP1—HP2—HP3的转变。首次在实验上观测到FePSe₃的高压新相HP2和HP3，并给出其可能的空间对称群。HP2相和HP3相具有超导电性，超导温度随压力的升高而降低，致使超导相图呈现“穹顶”状。研究结果为进一步厘清FePSe₃的压致相变行为提供了重要的实验支撑。