聚L-谷氨酸苄酯固定相的制备及色谱评价

利用L-谷氨酸苄酯开环聚合得到聚L-谷氨酸苄酯,对其进行表征,将聚L-谷氨酸苄酯溶于四氢呋喃后涂敷在3-氨丙基三乙氧基硅胶上制得液相色谱固定相,研究了正相色谱条件下聚L-谷氨酸苄酯涂敷型固定相对9种位置异构体及10种手性化合物的拆分能力。以不同比例的正己烷/异丙醇为流动相,有6种位置异构体(o,m,p-氯苯胺、o,m,p-溴苯胺、o,m,p-碘苯胺、o,m,p-硝基苯胺、o,m,p-二硝基苯和o,m,p-苯二胺)和4种手性化合物(1-(对氯苯基)乙醇、5-二硝基-N-(1-苯乙基)苯甲酰胺、华法林和四咪唑)得到不同程度的拆分,表明聚L-谷氨酸苄酯涂敷型固定相对位置异构体具有较好的识别作用,同时也表现出良好的手性拆分能力。     

Synthesis and Crystal Structure of a Novel 1D Mercury（II） Iodide Coordination Polymer Containing 40-Membered Macrocycle

A mercury coordination polymer [Hg3(TizT)2I6]n (Mr = 1921.72, TizT = 2,4,6- tri(imidazole-1-yl)-1,3,5-triazine) containing a 40-membered macrocycle which was constructed by four TizT ligands and four mercury(II) iodide molecules had been synthesized by the reaction of HgI2 with TizT. The complex was characterized by elemental analysis, FT-IR, 1H NMR spectra and X-ray crystallography. The crystal of the complex belongs to the monoclinic system and C2/c space group with a = 35.840(5), b = 8.169(5), c = 14.980(5) , β = 104.466(5)°, Z = 4, V = 4247(3) 3, Dc = 3.006 g·cm-3, μ = 15.223 mm-1, F(000) = 3384, Rint = 0.0504, wR = 0.0833 and constructs a chair-like conformation of cyclohexane one by one, which forms a 1-D polymer through the fashion of fused ring aromatic hydrocarbon. The hydrogen bonds and π-π interactions shape the 2-D network structure. The two compounds excited weak fluorescence.     

固相萃取-超高效液相色谱-电喷雾串联质谱法检测梨树叶中熊果苷

建立了固相萃取净化、超高效液相色谱-串联质谱检测梨树叶中熊果苷含量的方法.将粉碎的梨树叶样品用甲醇提取,ENVITM-18固相萃取柱净化,超高效液相-电喷雾串联四级杆质谱检测,外标法定量.测定时用 Acquity UPLC HSS T3 色谱柱(50 mm×2.1 mm,1.8μm)分离,甲醇-水(V/V,7+93)洗...     

Z形石墨带的电子输运性质: 形状与尺寸效应

基于格林函数方法及Landauer-Büttiker公式, 研究了纳米石墨带异质结的电子输运性质, 石墨带异质结由Z 形石墨带与两个锯齿型石墨带电极构成. 研究发现电导大小依赖其几何构型. 由于电子局域在锯齿型石墨带边缘, 因此在费米能级附近出现了电导隙或电导谷. 调节结间石墨带的宽度, 发现准束缚态的存在诱导许多尖锐的电导峰, 电导峰的数目几乎与结间的石墨带长度无关. 在低能区, 当θ为60°或150°时, 宽度均匀的Z型石墨带仍然保持弹道输运特征. 因此, Z形纳米石墨带可选择地应用于未来的纳微电路.     

对直接标准化算法的改进及其应用

由于各种仪器之间存在差异,主机上建立的定量模型用于从机会导致预测结果出现较大偏差。目前主要通过有标样方法和无标样方法来减小预测偏差。该文对现有标样方法中的直接标准化算法进行改进,在转移矩阵的建立过程中,对从仪器数据矩阵进行主成分分解,以预测均方差为判定标准,确定最终的转移矩阵。并以玉米和烟草数据为对象,测试了该法的有效性。玉米样品含有2种成分:水分和蛋白质;烟草样品含有4种成分:还原糖、总糖、总氮和总碱。结果表明,对于玉米样品中的2种成分,采用改进的方法可显著提高预测的准确度;对于烟草中的4种成分而言,采用改进的方法可获得稳健的预测结果。     

Comparison of Different Cartridges of Solid Phase Extraction for Determination of Polyphenols in Tobacco by UPLC/MS/MS and Multivariate Analysis

The comparison of solid phase extraction(SPE) for the preconcentration and isolation of polyphenols in tobacco samples was carried out by ultra-high performance liquid chromatography/tandem mass spectrometry (UPLC/MS/MS) and multivariate analysis.Several adsorbing materials of SPE(C18,NH2,SAX and OASIS) were investigated.It was found that the C18 and OASIS cartridges can not only speed up the purification process,but also simplify the SPE operation.A UPLC/MS/MS was used for the determination of polyphenols ...     

Effects of Hydroxyapatite Nanoparticles on Apoptosis and Invasion of Human Renal Cell Carcinoma 786-0 Cells

Renal cell carcinoma is the most common cancer of the kidney, and resistant to traditional therapies. The aim of this study is to investigate the effects of hydroxyapatite nanoparticles on human renal cell carcinoma 786-0 cells. Cell proliferation was assessed with an 3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazolium bromide(MTT) staining kit. The apoptosis assay was assessed with an FITC Annexin V Apoptosis Detection Kit. Caspase-3 and caspase-12 were detected by immunocytochemical staining and semi-qua...     

萝卜木质素的提取及其抗自由基活性

以浓度为80%的乙二醇水溶液为溶剂,采用高沸醇溶剂法(HBS)从萝卜中提取萝卜木质素,采用红外光谱、紫外光谱和~1H NMR等方法对其结构进行了表征.结果表明,所提取的萝卜木质素具有木质素类化合物的典型结构特征.采用可见光分光光度法研究了萝卜木质素对DPPH·自由基和HO·自由基的抑制效率.结果表明萝卜木质素对两种自由基均具有较高的抑制率,其对两种自由基的抑制率最高分别为90%和68.3%.     

Different charging behaviors between electrons and holes in Si nanocrystals embedded in SiN_x matrix by the influence of near-interface oxide traps

Si-rich silicon nitride films are prepared by plasma-enhanced chemical vapor deposition method,followed by thermal annealing to form the Si nanocrystals(Si-NCs)embedded in Si Nx floating gate MOS structures.The capacitance–voltage(C–V),current–voltage(I–V),and admittance–voltage(G–V)measurements are used to investigate the charging characteristics.It is found that the maximum flat band voltage shift(△VFB)due to full charged holes(～6.2 V)is much larger than that due to full charged electrons(～1 V).The charging displacement current peaks of electrons and holes can be also observed by the I–V measurements,respectively.From the G–V measurements we find that the hole injection is influenced by the oxide hole traps which are located near the Si O2/Si-substrate interface.Combining the results of C–V and G–V measurements,we find that the hole charging of the Si-NCs occurs via a two-step tunneling mechanism.The evolution of G–V peak originated from oxide traps exhibits the process of hole injection into these defects and transferring to the Si-NCs.     

钕敏化多层壳纳米结构的增强型染料敏化上转换发光

对于稀土离子掺杂的上转换发光,由于稀土离子吸收截面小、吸收范围窄,导致其发光强度受限。最近,在稀土上转换纳米粒子的表面连接近红外染料分子敏化发光,被证实是提高上转换发光强度的有效策略。然而,将染料分子连接经典的稀土Yb掺杂纳米粒子,并不能有效利用染料分子的敏化能力。针对这一问题,本文通过高温热分解法成功制备了Nd³⁺敏化的核/壳/壳(NaYF₄:Yb/Er(20/2%)@NaYF₄:Yb(10%)@NaYF₄:Nd(80%))纳米结构,与经典的IR-806敏化的NaYF₄:Yb/Er纳米结构相比,IR-806敏化的Nd³⁺掺杂的核/壳/壳纳米结构的上转换发光(500~700 nm)强度增强了约38倍。通过荧光光谱及荧光寿命分析证实,上转换发光强度增强源于Nd的吸收与近红外染料分子的有效交叠,以及壳层结构对发光中心的保护作用(Er³⁺(⁴S_3/2→⁴I_15/2)的寿命延长了1.7倍)。另外,研究发现纳米壳层结构中最外层掺杂的Yb³⁺离子将导致染料敏化发光减弱。进一步,这种IR-806敏化的Nd掺杂的核/壳/壳纳米结构可实现增强发光中心为Ho及Tm的上转换发光。本文研究为提高染料敏化上转换发光及应用提供了新途径。