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Controlled synthesis and magnetic properties of Fe_3O_4 walnut spherical particles and octahedral microcrystals

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Science China(Technological Sciences) 2008年第11期51卷 1911-1920页

作者： JIAO Hua1,2 & YANG HeQing1 1 Key Laboratory of Macromolecular Science of Shaanxi Province, School of Chemistry and Materials Science, Shaanxi Normal University, Xi’an 710062, China 2 Department of Chemistry and Chemical Engineering, Weinan Teachers University, Wei nan 714000, China Key Laboratory of Macromolecular Science of Shaanxi Province School of Chemistry and Materials Science Shaanxi Normal University Xi’an China Department of Chemistry and Chemical Engineering Weinan Teachers University Wei nan China

Magnetite Fe3O4 walnut spherical particles and octahedral microcrystals were suc- cessfully synthesized from K4 [Fe (CN) 6], K3 [Fe (CN) 6] and NaOH reagents via a simple hydrothermal process. And the uniform morphology of octahedral micro- crystals was obtained in the presence of ethylene glycol. The morphology and structure of products were characterized by powder X-ray diffraction, scanning electron microscopy and transmission electron microscopy. The results showed that the Fe3O4 walnut spherical particles and octahedral microcrystals were single crystals with the face-center cubic structure and with size distributions from 2.2 to 8.6 μm and 1.6 to 12.5 μm, respectively. Their magnetic properties were detected by a vibrating sample magnetometer at room temperature. The walnut spherical parti- cles exhibited a ferromagnetic behavior with the coercive force (Hc), saturation magnetization (Ms) and remanent magnetization (Mr) being 150.57 Oe, 97.634 and 12.05 emu/g, respectively. For the octahedral microcrystals they were 75.28 Oe, 101.90 and 6.69 emu/g, respectively. Different sizes of walnut spherical particles were controlled synthesized through adjusting the NaOH concentration. It was found that ethylene glycol molecules have a significant effect on the formation of Fe3O4 octahedra. A possible mechanism was also proposed to account for the growth of these Fe3O4 products

关键词： a hydrothermal route Fe3O4 walnut spherical particles octahedral microcrystals magnetic property

Intra-Articular injection of acid-sensitive stearoxyl-ketal-dexamethasone microcrystals for long-acting arthritis therapy

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Asian Journal of Pharmaceutical Sciences 2021年第2期16卷 213-221页

作者： Yang Xu Ziqi Chen Zunkai Xu Yanyan Du Jianghao Han Xiaoyong Yuan Shubiao Zhang Shutao Guo Key Laboratory of Functional Polymer Materials of Ministry of Education State Key Laboratory of Medicinal Chemical Biology and Institute of Polymer ChemistryCollege of ChemistryNankai UniversityTianjin 300071China Key Laboratory of Biotechnology and Bioresources Utilization of Ministry of Education Dalian Minzu UniversityDalian 116600China Clinical College of Ophthalmology Tianjin Medical UniversityTianjin Eye HospitalTianjin Key Laboratory of Ophthalmology and Visual ScienceTianjin Eye InstituteTianjin 300022China

Despite advances in treatment of chronic arthritis,there is still a strong need for the development of long-acting formulations that can enable local and sustained drug release at the inflamed *** this work,we fabricated microcrystals of an acid-sensitive stearoxyl-ketal-dexamethasone prodrug for treatment of *** of the prodrug with two sizes were successfully engineered and showed pH-dependent hydrolysis kinetics in *** a collagen-induced arthritis rat model,we evaluated the influence of particle size and injection dose on anti-inflammatory effect after intra-articular *** prodrug demonstrated long-acting anti-arthritis effects with good *** results indicate ketal-based prodrugs are promising for the development of long-acting injectables and may stimulate the development of new treatments for chronic diseases.

关键词： microcrystals Dexamethasone Prodrugs Long-acting formulations Arthritis

Synthesis and Upconversion Luminescence of LaF_3:Yb^(3+),Er^(3+)/SiO_2 Core/Shell microcrystals

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Journal of Rare Earths 2007年第5期25卷 605-608页

作者：王艳秦伟平张继森曹春燕张继双金叶 Key Laboratory of Excited State Processes Changchun Institute of Optics Fine Mechanics and Physics Chinese Academy of Sciences State Key Laboratory of Integrated Optoelectronics College of Electronic Science & Engineering Jilin University Changchun 130012 China

LaF3：Yb^3＋ , Er^＋ microcrystals were synthesized by a hydrothermal method, and then, the LaF3： Yb^3＋ , Er^＋ microcrystals were coated with silica. Phase identification of LaF3： Yb^3＋ , Er^＋ and LaF3： Yb^3＋ , Er^＋/SiO2 was performed via XRD. The TEM image showed that the size of LaF3： Yb^3＋ , Er^＋ was 150 nm and LaF3： Yb^3＋ , Er^＋/SiO2 presented clearly a core/shell structure with 20 nm shell thickness. The upconversion spectra of LaF3： Yb^3＋ , Er^＋ and LaF3： Yb^3＋ , Er^＋/SiO2 in solid state and in ethanol were studied with a 980 nm diode laser as the excitation source. The upconversion spectra showed that the silica shell had little effect on the properties of fluorescence of the LaF3：Yb^3＋ , Er^＋ microcrystals. At the same time, the green luminescence photo of LaF3： Yb3＋, Er3＋/SiO2 in the PBS buffer was obtained, which indicated that the LaF3： Yb^3＋ , Er^＋/SiO2 could be used in biological applications.

关键词： upconversion luminescence LaF3:Yb^3+ , Er^+ SiO2 core/shell microcrystals rare earths

Optical properties of nano-size ZnS semiconductor microcrystals doped with Mn^(2+) ions

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Chinese Science Bulletin 1995年第21期40卷 1782-1784页

作者：靳春明侯尚公窦恺陈一民黄世华虞家琪 Changchun Institute of Physics Chinese Academy of Sciences Changchun 130021 China

In recent years, me synthesis and optical properties of nano-size semiconductor particles were studied more extensively. Semiconductor (such as ZnS, CdS and GaP) nanometer microcrystallites were prepared in polymers, organic solutions and glasses. The quantum-size effects occurred and the optical properties were changed in those materials as the microcrystal radius decreased. Most of the previous studies were devoted to understanding the intrinsic properties and the interaction with surrounding medium. Bhargava

关键词： Mn2+-doped semiconductor microcrystals optical properties colloidal method transition metal.

Studies on the preparation and pharmacokinetics of puerarin microcrystals and nanocrystals for oral administration to rat

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Studies on the preparation and pharmacokinetics of puerarin ...

New design for multi-crystal data collection at SSRF

“好医生杯”中药制剂创新与发展论坛

作者： Liangxing Tu Yueneng Yi Wei Wu Fuqiang Hu Kaili Hu Jianfang Feng Murad Research Center for Modernized Chinese Medicine Shanghai University of Traditional Chinese Medicine School of Pharmacy Fudan University School of Pharmacy Zhejiang University

由中药葛根中提取而来的葛根素目前在临床上广泛用于心血管疾病的治疗。但由于其水溶性差和注射给药所带来的不良反应,目前迫切需要一种技术来用于葛根素口服给药制剂的开发。现如今,纳米结晶技术已慢慢成为难溶性药物口服制剂开发的首... 详细信息

由中药葛根中提取而来的葛根素目前在临床上广泛用于心血管疾病的治疗。但由于其水溶性差和注射给药所带来的不良反应,目前迫切需要一种技术来用于葛根素口服给药制剂的开发。现如今,纳米结晶技术已慢慢成为难溶性药物口服制剂开发的首选技术。在本研究中,我们分别采用高剪切分散法和高压均质法来制备粒径分别为1875.6 nm、525.8 nm的葛根素微米结晶和纳米结晶,并考察了不同粒径的制剂对于药物药动学的影响。同时我们采用DLS、DSC、XRD和SEM技术来对所制备的制剂进行表征,发现在制备过程中葛根素的晶型发生了变化并显示药物颗粒分散于HPMC中。在药动学的研究中,我们发现随着制剂粒径的减小,最大峰浓度(C)和曲线下面积(AUC)增加,同时消除率(CL/F)下降。纳米结晶的绝对生物利用度为21.44%,为葛根素原料药的7.6倍。以上实验结果显示,纳米结晶技术是一种能够有效提高葛根素口服生物利用度的技术。

关键词： puerarin nanocrystals microcrystals bioavailability particle size.

来源： cnki会议评论

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Nuclear Science and Techniques 2018年第2期29卷 48-56页

作者： Bing Li Sheng Huang Qiang-Yan Pan Min-Jun Li Huan Zhou Qi-Sheng Wang Feng Yu Bo Sun Jian-Qiao Chen Jian-Hua He Shanghai Institute of Applied Physics Chinese Academy of SciencesShanghai 201800China University of Chinese Academy of Sciences Beijing 100049China

Data collection with microcrystals at synchrotron radiation facilities is challenging because it is difficult to harvest and locate microcrystals. Moreover,microcrystals are sensitive to radiation damage; thus, typically, a complete data set cannot be obtained with a single microcrystal. Herein, we report a new method for data collection with multiple microcrystals having a crystal size ranging from 1 to 30 lm. This method is suitable for not only low-temperature(100 K) data collection but also room-temperature data collection. Thin Kapton membranes were used to capture multiple crystals simultaneously. The microcrystals were visible under an optical microscope and easily located because the membrane was transparent and sufficiently thin. The film was fixed to a bracket that was prepared using a three-dimensional printer. The bracket was fixed on a magnetic base via screwing and employed by the goniometer system for data collection. Multiple data sets of fatty acid-binding protein 4(FABP4) and lysozyme microcrystals were collected using this novel designed device. Finally, the structures of protein FABP4 and lysozyme were obtained from these data via the molecule replacement method. The data statistics reveal that this method provides a comparable result to traditional methods such as a nylon loop.

关键词： Kapton membrane microcrystals Multicrystal data collection Protein structure

Preparation of sol-gel derived microcrystalline corundum abrasives with hexagonal platelets

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International Journal of Minerals,Metallurgy and Materials 2013年第1期20卷 71-75页

作者： Na Li Yu-Mei Zhu Kai Gao Zhi-Hong Li Key Laboratory of Advanced Ceramics and Machining Technology School of Materials Science and Engineering Tianjin University

The effects of different additives on the mechanical properties, microstructures, and wear behavior of corundum abra- sives were investigated. When the number of additive phases increases, the sintering temperature and wear rate decrease, while the densification and mechanical properties increase. The additive SiO2 is responsible for the development of equiaxed grains, whereas both CaO and MgO promote the development of platelike grains. By controlling the molar ratio of additives, it is pos- sible to obtain different microstructures. With SiO2-MgO-CaO （molar ratio, 2：1：1） as the additives and nano a-Al203 powders as the seed, microcrystalline corundum abrasives with hexagonal platelets were obtained using sol-gel process by sintering at 1300℃ for 0.5 h. The average diameter and thickness of hexagonal platelets are 1.38 μm and 360 nm respectively, the sin- gle-particle compressive strength is 26.44 N, and the wear rate is （3.06±=0.21）× 10^-7 mm^3/（N.m）.

关键词： additives corundum microcrystals sol-gel process platelets compressive strength wear

Simple point contact WO_3 sensor for NO_2 sensing and relevant impedance analysis

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International Journal of Minerals,Metallurgy and Materials 2012年第12期19卷 1142-1148页

作者： Wu-bin Gao Yun-han Ling Xu Liu Jia-lin Sun School of Materials Science and Engineering University of Science and Technology Beijing Beijing 100083 China Department of Materials Science and Engineering Tsinghua University Beijing 100084 China

A simple and new point contact tungsten trioxide （WO3） sensor, which can be prepared by the oxidation of tungsten filaments via in-situ induction heating, likely detects low concentration （ppm level） environmental pollutants such as NO2. X-ray diffraction （XRD） and field emission scanning electron microscopy （FE-SEM） were applied to characterize the phase and the microstructure of the samples, respec-tively. It was found that the synthesized WO3 films exhibited a monoclinic phase and were composed of hierarchical microcrystals and nanocrystals. The point contact WO3 sensor （W-WO3-W） showed rectifying characteristics and an ideal sensing performance of about 110 C. A single semicircle in Nyquist plots was recorded by electrochemical impedance spectroscopy （EIS） at a relatively low temperature of 150 C but faded away above 200 C, which revealed that the sensing process was governed by a determining factor, i.e., grain boundaries at the contact site.

关键词： gas sensors tungsten trioxide metal oxide semiconductors thin fills microcrystals nanocrystals electrochemical impedancespectroscopy (EIS)

In vitro/vivo assessment of praziquantel nanocrystals: Formulation, characterization, and pharmacokinetics in beagle dogs

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Asian Journal of Pharmaceutical Sciences 2019年第3期14卷 321-328页

作者： Ruyi Yang Tao Zhang Jiang Yu Yan Liu Yingli Wang Zhonggui He Wuya College of Innovation Shenyang Pharmaceutical University

To investigate the impact of particle size on in vitro/vivo performance of praziquantel(PZQ), nanocrystals(NCs) and microcrystals(MCs) of PZQ were prepared using the methods of wet milling and jet milling, respectively. PZQ NCs and MCs were characterized with dynamic light scattering, laser particle size analyzer, transmission electron microscopy, differential scanning calorimetry, X-ray powder diffraction and fourier transform infrared spectroscopy. The average diameters of PZQ NCs and MCs were 364.4 nm and 3.7 μm, respectively. No change in crystalline form was observed. Dissolution tests were performed in two different media, where the cumulative dissolution and dissolution rate of NCs were significantly improved in comparison with those of MCs and KANGQING~? in non-sink condition. Similarly, oral bioavailability of PZQ NCs in beagle dogs was 1.68( P < 0.05) and 1.83 fold( P < 0.01) higher than that of MCs and KANGQING~? . Considering the advantages of in vitro/vivo performance and facile preparation, PZQ NCs may have a great application in the treatment of schistosomiasis.

关键词： Praziquantel Nanocrystals microcrystals Dissolution Pharmacokinetics