Sonochemical synthesis and fabrication of perovskite type calcium titanate interfacial nanostructure supported on graphene oxide sheets as a highly efficient electrocatalyst for electrochemical detection of chemotherapeutic drug

In green approaches for electrocatalyst synthesis, sonochemical methods play a powerful role in delivering the abundant surface areas and nano-crystalline properties that are advantageous to electrocatalytic detection. In this article, we proposed the sphere-like and perovskite type of bimetal oxides which are synthesized through an uncomplicated sonochemical procedure. As a yield, the novel calcium titanate (orthorhombic nature) nanoparticles (CaTiO₃ NPs) decorated graphene oxide sheets (GOS) were obtained through simple ultrasonic irradiation by a high-intensity ultrasonic probe (Titanium horn; 50 kHz and 60 W). The GOS/CaTiO₃ NC were characterized morphologically and chemically through the analytical methods (SEM, XRD, and EDS). Besides, as-prepared nanocomposites were modified on a GCE (glassy carbon electrode) and applied towards electrocatalytic and electrochemical sensing of chemotherapeutic drug flutamide (FD). Notably, FD is a crucial anticancer drug and also a non-steroidal anti-androgen chemical. Mainly, the designed and modified sensor has shown a wide linear range (0.015–1184 µM). A limit of detection was calculated as nanomolar level (5.7 nM) and sensitivity of the electrode is 1.073 μA μM⁻¹ cm⁻². The GOS/CaTiO₃ modified electrodes have been tested in human blood and urine samples towards anticancer drug detection.     

Electrochemical photoluminescence modulation of functional materials and their electrochemical devices

This paper describes overview of electrofluorochromism, which is a phenomenon that controls photoluminescence through a change in the redox states of functional molecules, metal complexes, polymeric films, etc. Electrofluorochromic materials are considered prospective innovative materials because they can convert electrical input into intuitive visual signals. This field opens novel systems by combining absorption, reflection, and luminescence properties, leading to high contrast, night and day visibility, low-cost displays, and various sensing applications. The former sections provided a short overview of the electrofluorochromic phenomena and observation setups. The electrofluorochromic reactions and devices synchronized with the absorption change based on the electrochemical reaction we reported were also reviewed.     

Rapid one-pot fabrication of magnetic calcium phosphate nanoparticles immobilizing DNA and iron oxide nanocrystals using injection solutions for magnetofection and magnetic targeting

This is the first report on rapid (5–30 min) one-pot fabrication of magnetic calcium phosphate (CaP) nanoparticles (NPs) co-immobilizing DNA and iron oxide (IO) nanocrystals with high immobilization efficiencies (DNA (～90%) and IO (～70%)). NPs were fabricated via coprecipitation under clean bench in supersaturated CaP solutions using DNA, IO-based MRI contrast agent, and infusion quality source solutions (even the water used was of injectable quality) that ensured high safety level of the fabrication process and product. Prepared DNA-IO-CaP NPs exhibited strong magnetic property allowing their noncontact manipulation by external magnet. These NPs were smaller than 500 nm, had relatively large negative zeta potential showing stable dispersion without any additional surfactant, and exhibited no significant cytotoxicity under the tested transfection conditions. The IO content of these NPs was significantly varied and by adjusting the initial IO concentration, DNA-IO-CaP NPs with gene delivery capability to CHO-K1 cells as high as that of the IO-free DNA-CaP NPs without external magnetic field were prepared. Fabricated DNA-IO-CaP NPs showed significantly improved gene delivery capability under external magnetic field compared to the IO-free DNA-CaP NPs. Thus, the present coprecipitation process can be considered as a novel technique to fabricate multifunctional CaP-based NPs to achieve magnetofection and targeted delivery.     

TEM preparation methods and influence of radiation damage on the beam sensitive CaCO3 shell of Emiliania huxleyi

The ultrastructure of biologically formed calcium carbonate crystals like the shell of Emiliania huxleyi depends on the environmental conditions such as pH value, temperature and salinity. Therefore, they can be used as indicator for climate changes. However, for this a detailed understanding of their crystal structure and chemical composition is required. High resolution methods like transmission electron microscopy can provide those information on the nanoscale, given that sufficiently thin samples can be prepared. In our study, we developed sample preparation techniques for cross-section and plan-view investigations and studied the sample stability under electron bombardment. In addition to the biological material (Emiliania huxleyi) we also prepared mineralogical samples (Iceland spar) for comparison. High resolution transmission electron microscopy imaging, electron diffraction and electron energy-loss spectroscopy studies revealed that all prepared samples are relatively stable under electron bombardment at an acceleration voltage of 300 kV when using a parallel illumination. Above an accumulated dose of ∼10⁵ e/nm² the material – independent whether its origin is biological or geological – transformed to poly-crystalline calcium oxide.     

Studies on shallow traps in Li2B4O7:Eu,Mn

Li₂B₄O₇ (LTB) single crystals doped with 0.5 mol% Mn and 0.005 mol% Eu have been grown by the Czochralski method. The presence of Eu³⁺ has been confirmed by photoluminescence spectra of non-irradiated crystals, whereas the presence of Mn²⁺ by absorption spectra of gamma-irradiated ones, as well as by EPR measurements. Unlike in most thermoluminescence studies on pure and doped LTB, performed usually above 300 K, glow curves have been recorded between 10 and 300 K in order to focus the attention on shallow traps. A broad, intense glow peak is observed around 80 K, with three weaker peaks at 205, 255, and 280 K. Based on supplementary T_max − T_stop experiments, the trap parameters have been derived assuming that the glow curve is in fact formed by a superposition of a double Gaussian band related to a quasi-continuous distribution of trapping levels, and several glow peaks produced by discrete traps. The nature of the traps is also discussed.     

一种对质子敏感Eu(Ⅲ)配合物的合成及性质

合成了一种新型铕配合物Eu(PTBMA)3(PTBMA为N-丙基-4-[4′-(2,2′:6′,2″-三联吡啶)基]-苯甲胺),通过紫外及荧光光谱对其质子化过程进行详细的研究。结果表明:低浓度质子的加入由于阻碍了配合物体系内的PET(Photo-induced electron transfer)过程,有利于Eu(Ⅲ)离子的5D0→7FJ(     

草酸铕颗粒微米层状颗粒的合成及其光学性能

Hierarchical europium oxalate Eu₂(C₂O₄)₃·10H₂O micro-particles were synthesized through a simple precipitation method at room temperature in present of trisodium citrate. The prod-ucts were characterized by X-ray diffraction, X-ray photoelectron spectroscopy, field-emission scanning electron microscopy, and photoluminescence. The possible formation mechanism of the hierarchical europium oxalate Eu₂(C₂O₄)₃·10H₂O micro-particles was discussed.     

新型β-二酮配体及其Eu(Ⅲ)三元配合物的合成、表征及发光性能的研究

采用Claisen缩合反应合成了一种新型的β-二酮化合物1-(4-溴苯)-3-苯基丙烷-1,3-二酮(L),并以其为第一配体,邻菲罗啉(Phen)为第二配体,合成出新型稀土Eu(Ⅲ)三元配合物。通过元素分析、红外光谱、紫外光谱、荧光光谱对合成的配体及三元配合物进行了表征。红外光谱的分析表明：配体L含有β-二酮结构,且烯醇式含量高;配合物中L的氧原子以及Phen中的氮原子与稀土离子进行了配位。紫外光谱的分析表明配合物中的能量传递主要来自第一配体。通过荧光光谱研究了配合物的发光性质,结果显示配合物表现出Eu3+的特征发射,主发射峰为Eu3+的5D₀ →7F₂发射,属于窄带发射,单色性较好,是具有潜在应用价值的红色发光材料。     

Differences in Adsorption of Anionic Surfactant AOT by Calcium Oxalate: Effect of Crystal Size and Crystalline Phase

The adsorption of anionic surfactant sodium diisooctyl sulfosuccinate(AOT) onto calcium oxalate monohydrate(COM) and dihydrate(COD) with sizes of 50, 100 nm, 1, 3 and 10 μm was comparatively studied to simulate the interaction between urinary crystallites and urine components. The adsorption quantity of different concentrations of AOT onto COD and COM with different sizes was detected using a UV-Vis spectrophotometer. The crystalline phase transition of COM and COD before and after adsorption was analyzed by X-ray powder diffraction and Fourier transform infrared spectrometry. The zeta potential of the crystal surface after adsorption of different concentrations of AOT was measured using a zeta potential analyzer. The adsorption quantity of AOT on COM and COD with different sizes was ranked in the following order: 50 nm>100 nm>1 μm>3 μm>10 μm. The adsorption quantity of COM was greater than that of COD with the same size because the density of the positive charges on the COM surface was higher than that on COD surface. With the increase of AOT concentration, the adsorption curves of the large-sized COM and COD(3 and 10 μm) were S-type, whereas the adsorption curves of the small-sized COM and COD(50 nm, 100 nm and 1 μm) were linear. The adsorption capacities of small-sized COM and COD were much greater than those of the 3 and 10 μm crystals. On the basis of the above results, we proposed a molecular model to summarize the absorption of AOT onto COM and COD crystals. Small crystals exhibit a large specific surface area and high surface energy. Thus, the adsorption capacities of them are stronger than those of large crystals. Overall, this study implies that small crystals can easily absorb anionic molecules in urine and may easily adhere to a negatively charged cell surface, thereby increasing the severity of cell injury.     

基于钙内标的贝壳元素成分微区LIBS分析方法研究

贝类生物作为海洋生态系统监测的理想标识,以Ca为内标进行元素比例变化的分析,将有可能获知气候演化及贝类生长等有用信息。区别于其他技术,微区激光诱导击穿光谱技术(Micro-LIBS：micro-probe laser induced breakdown spectroscopy)应用于贝类贝壳探测时,Ca的特征发射谱线将分布于整个光谱探测区间,如何选择合适谱线作为内标是Ca内标法用于贝壳成分元素分析的关键。以Ca元素为内标进行贝壳成分元素的Micro-LIBS探测,通过归一化Ca元素全谱谱线、最强离子谱线Ca Ⅱ 393.3 nm和不同强度原子谱线(Ca Ⅰ 422.7 nm/Ca Ⅰ 487.9 nm)为内标情况下Sr/Ca元素比例变化的比较,结果发现相较于Ca离子线Ca Ⅱ 393.3 nm和强度较弱原子线Ca Ⅰ 487.9 nm,以Ca元素全谱强度或最强原子线Ca Ⅰ 422.7 nm为内标时,Sr/Ca分布在贝壳分析区域内变化较小,其浮动分别小于7%和10%,符合贝壳分析区域为同一生长周期的纹理特征,较为准确地反映了贝壳的生长发展;同时,应用Ca全谱强度为内标对贝壳成分元素分析发现,元素比例Li/Ca, K/Ca, Na/Ca相较于Mn/Ca,具有明显的相似特征,说明海水富含轻质元素在贝壳生长分布上具有明显的相似性。研究结果表明,较强Ca原子线或全谱强度比Ca离子线更适合作为内标用于贝壳成分元素的微区LIBS分析,证明了Micro-LIBS用于贝壳分析的可行性。