硅肺发病前期肺中钙量的变化

硅肺发病前期肺钙变化的研究是探索Ca~(2 )在硅肺发生中的作用的重要内容。本文以离子选择性电极和Tb~(3 )-荧光光谱法首次检测了硅肺大鼠发病前期肺组织的钙量。结果表明:大鼠在染尘后3.5-14天,肺游离[Ca~(2 )]显著升高;肺[Ca~(2 )]的上升部分来自肺组织线粒体Ca~(2 )的释放。     

基于联萘酚衍生物的荧光传感器对Ca~(2+)的选择性测定

设计了基于联萘酚衍生物(LZ)的高选择性的荧光化学传感器,分别采用荧光光谱和紫外-可见光谱法研究了其对Ca~(2+)的识别.结果显示,与其他金属离子,如Ag~+、Al ~(3+)、Bi ~(3+)、Cd~(2+)、Co~(3+)、Cr~(3+)、Cu~(2+)、Fe~(3+)、Hg~(2+)、K~+、Mg~(2+)、Mn~(2+)、Ni ~(2+)、Pb~(2+)、Zn~(2+)相比,探针LZ对Ca~(2+)呈现良好的选择性.并且该探针在486nm处的荧光强度与Ca~(2+)浓度在2~7μmol/L范围内呈现良好的线性关系,其回归系数为0.994,检测限为0.8μmol/L,多次测定的相对标准偏差为2%.     

α-石英对离体巨噬细胞内游离Ca2+的影响

本文用荧光试剂Fura-2/AM和AR-CM-MlC阳离子测定系统研究了α-石英对离体肺泡巨噬细胞内游离Ca~(2+)的影响.结果表明:在含Ca~(2+)介质中,α-石英对巨噬细胞的毒性作用引起胞浆游离Ca~(2+)浓度的升高,α-石英剂量越大或作用时间增长,胞浆游离Ca~(2+)浓度升高越大,这种效应只能部分地被Ca~(2+)通道阻断剂异搏定所阻断.但在无Ca~(2+)介质中未观察到细胞胞浆游离Ca~(2+)浓度升高的现象.     

靶向检测Cu^(2+)和S^(2-)的多肽探针及其在细胞和斑马鱼成像中的应用EI北大核心CSCD

设计了一种新型多肽探针L(Dansyl-Gly-Ser-Ser-Gly),该多肽探针L单独存在时有强的荧光信号,Cu^(2+)的顺磁性淬灭传感机制可导致多肽探针L的荧光淬灭。因此探针L可以靶向检测Cu^(2+)而不受其他常见金属离子的干扰。滴定和Job工作曲线结果表明,L-Cu检测平台以摩尔比1∶1的方式结合,结合常数为8.60×10^(4)L/mol。计算机模拟结果表明,Cu^(2+)与多肽探针L中的2个丝氨酸上的氮原子结合。S^(2-)的加入使L-Cu检测平台中的多肽探针L游离出来,多肽探针L的荧光恢复。多肽探针L能够实现对Cu^(2+)和S^(2-)的靶向检测,并以“On-Off-On”模式响应,检出限分别为114 nmol/L和357 nmol/L。多肽探针L已成功用于L929细胞和斑马鱼中Cu^(2+)和S^(2-)的荧光成像,为人体内靶向检测Cu2+和S2-提供了一种新的机遇。     

基于杯[4]冠醚的1,3,4-噁二唑荧光探针的合成及对金属离子的识别

分别以2-苯基-5-(2-吡啶基)-1,3,4-噁二唑及2,5-二苯基-1,3,4-噁二唑为荧光基团,设计合成了基于杯[4]冠醚结构的荧光探针分子1a和1b;利用核磁共振氢谱(~1H NMR)、碳谱(~(13)C NMR)及高分辨质谱(HRMS)表征了其结构.采用紫外-可见光谱及荧光光谱考察了探针分子1a和1b对碱金属离子(Na~+,K~+,Cs~+)、碱土金属离子(Mg~(2+),Ca~(2+))及过渡金属离子(Mn~(2+),Co~(2+),Ni~(2+),Cu~(2+),Zn~(2+),Cd~(2+),Ag~+)的识别作用.结果表明,Na~+可使探针分子1a的二氯甲烷溶液荧光强度显著增强,K+和Cs~+对探针分子1a的荧光强度几乎无影响,而Ca~(2+)及所有过渡金属离子均可有效猝灭探针分子1a的荧光.探针分子1b对于碱金属离子的识别作用与探针分子1a相似,但其与过渡金属离子的络合作用弱于探针分子1a.根据核磁共振表征结果讨论了金属离子与荧光探针的络合位点.     

新型香豆素类Zn~(2+)荧光探针的合成及细胞成像研究

设计、合成了一种光诱导电子转移(Photoinduced Electron Transfer,PET)型香豆素类水溶性Zn~(2+)荧光探针1和2.通过荧光光谱分析实验发现,该探针具有较好的选择性和灵敏度,其荧光强度随着Zn~(2+)的浓度增大而逐渐增强,并可成功实现对人乳腺癌细胞(MCF-7)和枯草杆菌(B.subtilis)的标记.目标探针分子结构均经1H NMR,13C NMR,IR,HRMS及X单晶射线衍射进行了表征,并且还获得了探针2与Zn~(2+)络合物[Zn(2)]的单晶结构,X单晶衍射实验表明络合物[Zn(2)]中Zn~(2+)为五配位,其几何构型为双锥体.     

Tb~(3+)配合物修饰的磁性纳米荧光探针对水中Cu~(2+)的超灵敏检测

合成了一种Tb~(3+)配合物修饰的磁性纳米荧光探针cs124-DTPA-NH-PEGDBI-Fe3O4∶Tb。该复合荧光探针与Cu~(2+)有很强的结合能力,Cu~(2+)对Tb~(3+)配合物修饰的磁性纳米荧光探针具有荧光猝灭作用。实验表明,该复合荧光探针稳定性良好且有很好的水溶性,可在较宽的pH范围(5.0~10.0)快速检测Cu~(2+)。此外,在竞争实验中发现,该纳米荧光探针能够实现对溶液中Cu~(2+)的超灵敏和选择性检测而对其他多种常见离子响应较小,对Cu~(2+)的检测限甚至可达到1nmol/L。     

卵磷脂抗石英毒作用的研究

本文采用家兔肺泡巨噬细胞(AM)体外培养法,以细胞内游离钙浓度([Ca~(2+)]_i)、细胞存活率、乳酸脱氢酶(LDH)和酸性磷酸酶(ACP)活性为指标,观察了卵磷脂、脑磷脂及现用防治硅肺药物克矽平(PVPNO)、柠檬酸铝等抗石英毒效果。结果表明:卵磷脂在所试各药物中效果最佳.初步探讨了卵磷脂拮抗石英细胞毒性的机理.卵磷脂有成为防治硅肺药物的可能性.     

一种基于AIE机理识别Fe2+的荧光探针研究

合成了一种基于苯并噻唑衍生物的Fe~(2+)荧光探针YBTM。YBTM具有聚集诱导发光(AIE)性质,考察了YBTM在DMF/H_2O混合溶液中的荧光性质。在DMF/H_2O(1/9,v/v,HEPES 10 m M,p H=7.4)溶液中,探针YBTM对Fe~(2+)具有良好的选择性,Fe~(2+)可引起荧光猝灭,探针对Fe~(2+)响应快速,检测限为2.46×10~(-6)M。以酒石酸二铵作为掩蔽剂消除Fe~(3+)的潜在干扰。此外,探针YBTM可用于MCF-7细胞中Fe~(2+)的荧光成像。     

高灵敏度席夫碱镁离子荧光探针的合成及识别性能研究

以对氨基苯甲酰肼为连接基团,分别通过氨基和酰肼基团引入丹磺酰氯和2-羟基-1-萘醛,制备了新型席夫碱(Schiff's base)类荧光探针TZ,实现了对镁离子(Mg~(2+))的高灵敏度识别。利用电喷雾质谱、紫外光谱、荧光光谱等研究了荧光探针TZ对Mg~(2+)的识别作用与机理。紫外光谱表明,单纯探针TZ在386.5 nm出现了萘醛的特征吸收峰;当探针TZ与Mg~(2+)结合后,在411 nm处出现新的吸收峰,等吸收点为400 nm。荧光光谱表明,探针TZ与Mg~(2+)结合后激发波长红移到400 nm,在发射波长468 nm处荧光强度增强10倍,量子产率为0.57。当向TZ中加入其它金属离子(Li~+、Na~+、K~+、Zn~(2+)、Ca~(2+)、Mn~(2+)、Cd~(2+)、Pb~(2+)、Ag~+等)时,荧光强度并未发生明显变化,表明TZ对Mg~(2+)具有较高的选择性。通过ESI-MS滴定和Job's plot曲线确定了TZ与Mg~(2+)的配位模式为1∶1的关系,检出限可达0.13μmol/L。     

Luminescence Properties of Ca2Ga2SiO7:RE Phosphors for UV White‐Light‐Emitting Diodes

A series of Eu²⁺‐, Ce³⁺‐, and Tb³⁺‐doped Ca₂Ga₂SiO₇ phosphors is synthesized by using a high‐temperature solid‐state reaction. The powder X‐ray diffraction and structure refinement data indicate that our prepared phosphors are single phased and the phosphor crystalizes in a tetrahedral system with the ${P\bar 42m}$ (113) space group. The Eu²⁺‐ and Ce³⁺‐doped phosphors both have broad excitation bands, which match well with the UV light‐emitting diodes chips. Under irradiation of λ=350 nm, Ca₂Ga₂SiO₇:Eu²⁺ and Ca₂Ga₂SiO₇:Ce³⁺, Li⁺ have green and blue emissions, respectively. Luminescence of Ca₂Ga₂SiO₇:Tb³⁺, Li⁺ phosphor varies with the different Tb³⁺ contents. The thermal stability and energy‐migration mechanism of Ca₂Ga₂SiO₇:Eu²⁺ are also studied. The investigation results indicate that the prepared Ca₂Ga₂SiO₇:Eu²⁺ and Ca₂Ga₂SiO₇:Ce³⁺, Li⁺ samples show potential as green and blue phosphors, respectively, for UV‐excited white‐light‐emitting diodes.     

Influence of composition on corroding process of Na<Subscript>2</Subscript>O-K<Subscript>2</Subscript>O-CaO-ZrO<Subscript>2</Subscript>-SiO<Subscript>2</Subscript> glasses

The corroding process of six glasses of the Na₂O-K₂O-CaO-ZrO₂-SiO₂ system with ZrO₂content 0–2.13 mass % by water was observed during static tests at 121°C and pressure of 0.25 MPa in steam sterilizer. Significant increase of Na⁺ and K⁺ content in leachates was observed after the addition of ZrO₂ into glass. Further increase of the content of ZrO₂ in glasses slowed down the rate of Na⁺ and K⁺ leaching. The leaching process of SiO₂ as well as Na⁺, K⁺, and Ca²⁺ ions was evaluated on the basis of comparison with model leaching processes. Variation of the concentrations of Na⁺, K⁺, Ca²⁺, and SiO₂ in leachates with time was described by empirical equation. Observed changes in the initial leaching rates of Na⁺, K⁺, Ca²⁺, and SiO₂ can be ascribed to the content of ZrO₂ in glasses. The presence of ZrO₂ in glasses reduced the overall rate of glass dissolution.     

CALCIUM AS POTENTIAL DETERMINING ION IN AQUEOUS CALCITE SUSPENSIONS

Electrokinetic mobility was measured on calcite particles dispersed in aqueous solutions as a function of pH, ion concentration and type (Na⁺, Ca²⁺, CI^-, S0₄ ^2-). Whatever the pH value, experimental results show a good correlation between electrokinetic potential and Ca²⁺ activity. Considering Ca²⁺ as a potential determining ion and using a simple complexation model at the surface, we show that the displacement of the isoelectric point can be attributed to the relative affinity of CO₃ ^2- and Ca²⁺ for the surface.     

Electrochemical Capacitive K+ EMIS Chemical Sensor Based on the Dibromoaza[7]helicene as an Ionophore for Potassium Ions Detection

A K⁺‐sensitive capacitive electrolyte‐membrane‐insulator‐semiconductor (EMIS) based on a novel dibromoaza[7]helicene ionophore has been developed. An ion‐sensitive membrane based on polyvinylchloride (PVC) doped with the ionophore was deposited on the Si₃N₄/SiO₂/Si‐p/Cu‐Al transducer. The properties of the K⁺‐EMIS chemical sensor were investigated by electrochemical impedance spectroscopy (EIS). All the developed devices upon being tested have shown good sensitivity and linearity responses within the range 10^?6 M to 10^?1 M of potassium activity, with good selectivity over a wide variety of other cations (Na⁺, Li⁺, Cu²⁺, Ca²⁺, and Mg²⁺). To our knowledge, this is the first time that a capacitive field‐effect sensor has been fabricated using helicene as a carrier for K⁺‐detection, combined with the structure: Si₃N₄/SiO₂/Si‐p/Cu‐Al as a transducer.     

Bis(naphthol)-based fluorescent chemoprobe for cesium cation and its immobilisation on silica nanoparticle as a high selective adsorbent

Abstract

A bis(naphthol)-based cation receptor 1 has been synthesised by three steps of synthetic procedure. The spectroscopic properties of 1 upon addition of various metal ions were investigated by UV–vis absorption and fluorescence spectroscopy. As a result, the absorption of 1 was linearly decreased as a function of concentration of added Cs⁺. Also, 1 exhibited dramatic fluorescence quenching effect upon exposure to caesium cation. Contrastively, no significant quenching effect was observed upon addition of other metal ions such as Na⁺, K⁺, Rb⁺, Mg²⁺, Ca²⁺, Sr²⁺, Ba²⁺, Ni²⁺ and Zn²⁺. It was found that 1 formed a 1:1 complex with Cs⁺ by Job’s plot. Furthermore, we also prepared 1-functionalised silica nanoparticle (SiO₂-1) as an adsorbent for Cs⁺. SiO₂-1 showed a great capacity for selective removal of caesium ion from aqueous solution as well as from tap water. Thus, it is potentially useful for the detection and removal of caesium cation from environmental and biological fluids polluted by nuclear radiation and nuclear waste.     

Adsorption behaviors of strontium using macroporous silica based hexagonal tungsten oxide

A novel macroporous silica-based hexagonal tungsten oxide (h-WO₃/SiO₂) with exchangeable sodium cations located in hexagonal tunnel structure was synthesized by a facile hydrothermal treatment of sodium tungstate dihydrate with 1 mol/L HCl solution. Utilization of the h-WO₃/SiO₂ adsorbent to remove aqueous strontium was investigated under the condition of various pH values, contact time, the initial concentration of metal ions, salt ion concentration, and coexisting ions. According to the experimental data, Sr²⁺ adsorption equilibrium was achieved within 15 min in acidic solution, and the maximum removal capacity of Sr²⁺ occurred at pH 4. The kinetic adsorption of Sr²⁺ on h-WO₃/SiO₂ was controlled by pseudo second-order model, and the saturated adsorption of Sr²⁺ on h-WO₃/SiO₂ was better described by Langmuir and Redlich-Peterson isotherm models compared with the Freundlich isotherm model. The distribution coefficient of Sr²⁺ was more than 2000 cm³/g in the presence of Ca²⁺, Mg²⁺, La³⁺, and Eu³⁺, indicating that the h-WO₃/SiO₂ showed excellent selectivity towards Sr²⁺ in pH 4.     

Ion-selective field effect transistors with polymeric membranes

The construction and operation of ion-selective field effect transistors (ISFET) with polymeric membranes are described, and their electrical and chemical performance are discussed. The H⁺, K⁺, and Ca²⁺ ISFET's all show responses similar to those of the corresponding ion-selective electrodes, with t_95% response times of approximately 40 ms and accurate ion activity measurements for periods up to one month.     

Approach to De-NOx-ing photocatalysis. II excited state of copper ions supported on silica and photocatalytic activity for no decomposition

Cu²⁺ ions supported on SiO₂ (Cm²⁺ /SiO₂) prepared by an ion-exchange method are reduced to Cu⁺ when Cu²⁺/SiO₂ samples are evacuated at temperatures higher than 573 K Reduced Cu²⁺ ions on SiO₂ (Cu⁺/SiO₂ catalyst) decomposes NO molecules photocatalytically and stoichiometrically into N₂ and O₂ at 275 K. The physicochemical and photochemical properties of copper ions anchored onto SiO₂ have been investigated by means of ESR and dynamic photoluminescence spectroscopies, as well as the analysis of photoreaction products. These results indicate that the excited state of the copper ions (Cu⁺ species) plays a significant role in the photocatalytic decomposition of NO molecules and the photoreaction involves an electron transfer from the excited state of the Cu⁺ ion into an anti-bonding π orbital of NO molecule within the lifetime of its excited state. Thus, the present results obtained with the Cu⁺/SiO₂ catalysts imply the possibility of their utilization as a potentially promising type of photocatalysts in gas-solid systems.     

Synthesis and characterization of novel blue emitting Na2CaSiO4:Ce3+ phosphor

The blue phosphors Na_(2?x)Ca_(1?x)SiO₄:xCe³⁺ were synthesized by the sol–gel method and their luminescence characteristics were investigated for the first time. Structural information about prepared samples is obtained by analyzing the XRD patterns and SEM micrographs. The photoluminescence (PL) excitation spectra indicate that the Na_(2?x)Ca_(1?x)SiO₄:xCe³⁺ phosphors can be effectively excited by ultraviolet (360 nm) light. The PL emission spectra exhibit tunable blue broadband emission with the dominant wavelength of 427–447 nm under excitation of 360 nm by controlling the doping concentration of Ce³⁺. The concentration quenching effect for Ce³⁺ was found at the optimum doping concentration of 4 mol%. The Commission Internationale de l’Eclairage 1931 chromaticity coordinates of Na_1.96Ca_0.96SiO₄:0.04Ce³⁺ are (0.1447, 0.0787), which are better color purity compared to the commercial Eu²⁺-doped BaMgAl₁₀O₁₇ phosphor. Na_1.96Ca_0.96SiO₄:0.04Ce³⁺ composition shows intense blue emission (peak wavelength, 439 nm) with relative intensity versus commercial BaMgAl₁₀O₁₇:Eu²⁺ blue phosphor (Nichia) 65 and 158 % under 254 and 365 nm excitation, respectively. All the results indicate that Na_(2?x)Ca_(1?x)SiO₄:xCe³⁺ phosphors are potential candidate as a blue emitting phosphor for UV-converting white light-emitting diodes.     

Sorption properties of oxides—VII: Reversibility of cation exchange on hydrous thorium oxide

Li⁺Ca²⁺, Na⁺Ca²⁺, K⁺Ca²⁺ and NH₄⁺Ca²⁺ exchanges at 0.01 M OH⁻ concentration and Co²⁺Cu²⁺, Ni²⁺Cu²⁺ and Zn²⁺Cu²⁺ exchanges from neutral solutions on hydrous thorium oxide were studied at room temperature. Except NH₄⁺Ca²⁺ exchange, all other exchanges investigated were non-reversible. Results indicate that specific chemical interactions play an important role during the exchange and/or sorption process.