Size-Dependent Persistent Luminescence of YAGG:Cr3+ Nanophosphors

In the current work, YAGG:Cr³⁺ nanophosphors were synthesized by the Pechini method and then annealed at different temperatures in the range 800–1300 °C. The structure and morphology of the samples were characterized by X-ray Powder Diffraction (XRPD). The lattice parameters and average crystalline sizes as site occupation by Al³⁺ and Ga³⁺ ions were calculated from the Rietveld refinement data. To investigate the effect of crystalline size of the materials on their optical properties: excitation and emission spectra were recorded and analyzed. Finally, the effect of crystalline size on the probability of carrier recombination leading to PersL was determined experimentally with thermoluminescence analyses. The T_max-T_stop method was applied to determine the trap type and particle size (calcination temperature) effect on their redistribution. A correlation between structural changes and trap redistribution was found. In particular, the extinction of high-temperature TL maximum with increasing annealing temperatures is observed, while low-temperature TL maximum increases and reaches a maximum when the lattice parameter reaches saturation.     

Approaches to Preceramic Polymer Fiber Fabrication and On-Demand Applications

The demand for lightweight, high-modulus, and temperature-resistant materials for aerospace and other high-temperature applications has contributed to the development of ceramic fibers that exhibit most of the favorable properties of monolithic ceramics. This review demonstrates preceramic-based polymer fiber spinning and fiber classifications. We discuss different types of fiber spinning and the advantages of each. Tuning the preceramic polymer chemical properties, molar mass, functional chemistry influences, and incorporation with fillers are thoroughly investigated. Further, we present the applications of preceramic-based polymer fibers in different fields including aerospace, biomedical, and sensor applications. This concise review summarizes recent developments in preceramic fiber chemistry and essential applications.     

金属冠脉支架磁共振适用性检测方法

目的:建立金属冠脉支架磁共振适用性实验平台,以实验室测试为基础,研究金属冠脉支架的磁共振适用性。方法:金属冠脉支架磁共振适用性试验分为四个部分,在3T磁共振环境下,分别进行磁位移力试验、磁扭矩试验、致热试验和图像干扰试验。结果:退磁效果好的金属冠脉支架,磁位移力小于其自身重力,磁扭矩小于其自身重力扭矩,温度升高值小,图像畸变值小。退磁效果不好的支架,磁位移力大于其自身重力,温度升高多,图像畸变值大。结论:实验平台可以对金属冠脉支架磁共振适用性进行检测,并对其退磁效果进行评价。     

原子荧光光度法测定常通口服液中重金属砷的含量

目的测定中药常通口服液中重金属砷（As）的含量。 方法采用原子荧光光度法，负高压300 V，光源用砷空心阴极灯，灯电流为60 mA，原子化器高度8.0 mm，载气流量300 mL·min^-1，屏蔽气流量700 mL·min 1。结果重金属砷在0.4～25.6 ng·mL^-1浓度范围内线性关系良好，r＝0.999 7，平均回收率为98.27%，RSD＝2.83%（n＝5）。结论该法简单、快速、灵敏，常通口服液中重金属砷含量符合规定。     

中药中外源性有害残留物的控制

分析了中药中外源性有害残留的种类及危害、对其研究进展进行了全面回顾,综述了国内外的监控情况。     

川崎病血清MMP-3、MMP-9及其TIMP-1水平变化及与冠状动脉病变的关系

目的检测川崎病患儿血清中基质金属蛋白酶-3（MMP-3）、基质金属蛋白酶-9（MMP-9）及其特异性组织抑制剂-1（TIMP-1）水平的变化,以探讨上述因子水平的变化与冠状动脉病变的关系。方法收集2011年1月～2012年9月在本院儿科住院的川崎病患儿,设为观察组,采取ELISA法测定川崎病患儿急性期和恢复期血清MMP-3、MMP-9和TIMP-1的含量,并与同期进行健康体检的正常健康儿童（设为对照组）进行对比观察,通过心脏彩超检查明确川崎病患儿冠状动脉损伤情况。结果观察组与对照组MMP-3、MMP-9、TIMP-1检测值及MMP-3/TIMP-1、MMP-9/TIMP-1比较,差异均有统计学意义（P〈0.05、P〈0.01）;观察组中有冠状动脉病变组各检测因子结果与无冠状动脉病变组比较差异有统计学意义（P〈0.01）。结论 MMP-3、MMP-9与TIMP-1均参与了川崎病的病理生理过程,对早期诊断冠状动脉病变有提示作用,且MMP-3/TIMP-1、MMP-9/TIMP-1比值持续失调可判断冠状动脉炎症病变的严重程度。     

青霉素V钾胶囊微生物限度检查法的方法学研究

目的:建立青霉素V钾胶囊的微生物限度检查方法。方法:分别采用平皿法、培养基稀释法和薄膜过滤法(每膜100、300、500 ml+青霉素酶)对青霉素V钾胶囊进行微生物限度检查法的研究及控制菌的检查(每膜100、200 ml)。结果 :细菌检查采用薄膜过滤法(每膜500 ml、大于300万u青霉素酶),霉菌和酵母菌采用平皿法,控制菌采用薄膜过滤法(每膜200 ml)时,细菌、霉菌和酵母菌回收率均大于70%。结论:采用薄膜过滤法检查青霉素V钾胶囊中的细菌,平皿法检查霉菌及酵母菌,薄膜过滤法检查控制菌,结果可靠。     

Microstructure and Mechanical Properties of Metal Foams Fabricated via Melt Foaming and Powder Metallurgy Technique: A Review

Metal foams possess remarkable properties, such as lightweight, high compressive strength, lower specific weight, high stiffness, and high energy absorption. These properties make them highly desirable for many engineering applications, including lightweight materials, energy-absorption devices for aerospace and automotive industries, etc. For such potential applications, it is essential to understand the mechanical behaviour of these foams. Producing metal foams is a highly challenging task due to the coexistence of solid, liquid, and gaseous phases at different temperatures. Although numerous techniques are available for producing metal foams, fabricating foamed metal still suffers from imperfections and inconsistencies. Thus, a good understanding of various processing techniques and properties of the resulting foams is essential to improve the foam quality. This review discussed the types of metal foams available in the market and their properties, providing an overview of the production techniques involved and the contribution of metal foams to various applications. This review also discussed the challenges in foam fabrications and proposed several solutions to address these problems.     

Evaluation of the Biocompatibility and Osteogenic Properties of Metal Oxide Coatings Applied by Magnetron Sputtering as Potential Biofunctional Surface Modifications for Orthopedic Implants

Biomaterials with adequate properties to direct a biological response are essential for orthopedic and dental implants. The surface properties are responsible for the biological response; thus, coatings with biologically relevant properties such as osteoinduction are exciting options to tailor the surface of different bulk materials. Metal oxide coatings such as TiO₂, ZrO₂, Nb₂O₅ and Ta₂O₅ have been suggested as promising for orthopedic and dental implants. However, a comparative study among them is still missing to select the most promising for bone-growth-related applications. In this work, using magnetron sputtering, TiO₂, ZrO₂, Ta₂O₅, and Nb₂O₅ thin films were deposited on Si (100) substrates. The coatings were characterized by Optical Profilometry, Scanning Electron Microscopy, Energy-Dispersive X-ray Spectroscopy, X-ray Photoelectron Spectroscopy, X-ray Diffraction, Water Contact Angle measurements, and Surface Free Energy calculations. The cell adhesion, viability, proliferation, and differentiation toward the osteoblastic phenotype of mesenchymal stem cells plated on the coatings were measured to define the biological response. Results confirmed that all coatings were biocompatible. However, a more significant number of cells and proliferative cells were observed on Nb₂O₅ and Ta₂O₅ compared to TiO₂ and ZrO_2. Nevertheless, Nb₂O₅ and Ta₂O₅ seemed to induce cell differentiation toward the osteoblastic phenotype in a longer cell culture time than TiO₂ and ZrO₂.     

Adsorption of Heavy Metals Ions from Mining Metallurgical Tailings Leachate Using a Shell-Based Adsorbent: Characterization,Kinetics and Isotherm Studies

This study defines the optimal parameters that allow the use of waste mollusk shells (WS) to remove heavy metals from three mining and metallurgical leachates. First, the influence of parameters such as pH, contact time, initial metal concentration, adsorbent dose and the presence of co-ions in Cu²⁺, Cd²⁺, Zn²⁺ and Ni²⁺ adsorption was investigated in synthetic solutions. Metal uptake was found to be dependent on the initial pH of the solution, the removal rate increasing with the increase in pH, showing the highest affinity at pH 5–6. The removal efficiency at lower concentrations was greater than at higher values. The competitive adsorption results on bimetallic solutions showed that the adsorption capacity of the sorbent was restricted by the presence of other ions and suppressed the uptake of heavy metals compared to the single adsorption. Cu²⁺ was the metal that most inhibited the removal of Cd²⁺, Zn²⁺ and Ni²⁺. The Langmuir isotherm provided the best fit to the experimental data for Cu²⁺, Cd²⁺ and Zn²⁺ and the Freundlich isotherm, for Ni²⁺. The data showed that the maximum adsorption capacity a_max for Zn²⁺, Cd²⁺ and Cu²⁺, was 526.32 mg g⁻¹, 555.56 mg g⁻¹ and 769.23 mg g⁻¹, respectively. Sorption kinetics data best fit the pseudo-second-order kinetic model. The results obtained in the tests with three mining and metallurgical leachates showed that WS were effective in simultaneously removing several heavy metals ions such as Cu, Ni, Zn, Cd, Ni, As and Se.