FHA涂层的制备及生物活性

采用沉淀法制备了F掺杂HA的FHA(Ca_(10)(PO_4)_6(OH)F)粉末,并通过电泳沉积在钛合金(Ti6Al4V)表面制备了FHA涂层。通过X射线衍射(XRD),扫描电镜(SEM),能谱仪(EDS)研究了基体预处理方式对涂层形貌和结合力的影响,并且研究了涂层的生物活性。结果表明:酸处理后涂层表面有微裂纹存在,酸处理+碱处理后的涂层表面无裂纹并具有更高的结合强度;FHA涂层浸泡后表面形成缺钙类骨磷灰石,成花瓣状生长,长度为几百纳米,具有优良的生物活性。     

Surfactant-free electrochemical synthesis of fluoridated hydroxyapatite nanorods for biomedical applications

Fluoridated hydroxyapatite (FHA) [Ca₁₀(PO₄)₆F_x(OH)_2−x, x = 0–2] is believed to be a promising calcium phosphate (CaP) to replace pure hydroxyapatite (HA) for next-generation implants, owing to its better biocompatibility, higher antibacterial activity, and lower solubility. Notably, the shape and size of the CaP crystals play key roles in their performance and can influence their applications. One-dimensional (1D) FHA nanorods are important CaP materials which have been widely used in regenerative medicine applications such as restorative dentistry. Unfortunately, the traditional synthesis methods for FHA nanorods either employ surfactants or take a relatively long time. In this study, we aimed to propose a facile synthesis route to fabricate FHA nanorods without any surfactants using an electrochemical deposition method for the first time. This study focused on preparing FHA nanorods without the assistance of any surfactant, unlike the traditional synthesis methods, to avoid chemical impurities. FHA nanorods with lengths of 124–2606 nm, diameters of 28–211 nm, and aspect ratios of 4.4–21.8 were synthesized using the electrochemical method, followed by a heat treatment. For the as-synthesized FHA nanorods, the Ca/P ratio was 1.60 and the atomic concentration of F was 2.06 at.%. An ultrastructure examination revealed that each FHA nanorod possessed long-range order, good crystallinity, and a defect-free lattice with a certain crystallographic plane orientation along the whole rod. In short, we propose a novel, surfactant-free, cost-saving, and more efficient route to synthesize FHA nanorods which can be widely applied in multiple biomedical applications, including drug delivery, bone repair, and restorative dentistry.     

Electrophoretic deposition of fiber hydroxyapatite/titania nanocomposite coatings

Hydroxyapatite/titania nanocomposite coatings were electrophoretically deposited from ethanolic suspensions of titania and fiber shaped hydroxyapatite (FHA) nanoparticles. Triethanolamine (TEA) was used to enhance the colloidal stability of particles in suspensions. Electrophoretic deposition (EPD) was performed using the suspensions with different concentrations (wt%) of titania/FHA particles. EPD rate decreased more rapidly with time for suspensions with higher wt% of FHA due to the higher voltage drop over the deposits shaped from them. Stacking of long FHA particles on the substrate during EPD resulted in the formation of coarse pores in the deposits. It was found that titania nanoparticles can more efficiently infiltrate through and fill the pores in TEA containing suspensions due to the stronger electrostatic repulsion force between pore walls (FHA) and titania nanoparticles in them. The coatings deposited from the suspensions with 50 wt% of FHA or more did not crack during drying due to the significant reinforcement action provided by high wt% of FHA in them. Nanocomposite coatings deposited from TEA containing (2 mL/L) suspensions with 50 and 75 wt% of FHA had the best corrosion resistance in simulated body fluid (SBF) solution due to their crack-free microstructure and efficiently filled pores.     

基于FHA的LLC变换器稳态分析

基于对LLC谐振变换器稳态特性的详细分析,推导出一种针对LLC变换器的设计方法。该分析是基于“一次谐波近似“理论,该理论可极大地简化系统的模型,将系统模型线性化,可用经典的交流电路补偿分析方法对系统进行分析。     

生物涂层制备技术的研究现状及进展

羟基磷灰石(HA)由于具有良好的生物相容性和骨组织诱导性,被认为是替代人体硬组织的一种很好的生物医用材料,但其溶解度较高,降低植入体的长效性,而将氟渗入HA晶格中能提高HA结构稳定性并降低其溶解性,将硅掺入HA晶格中能有效地提高HA的生物活性,因此含氟羟基磷灰石(FHA)和含硅羟基磷灰石(Si-HA)成为了新兴的改性材料。介绍了羟基磷灰石(HA)、含氟羟基磷灰石(FHA)以及含硅羟基磷灰石(Si-HA)的性能特点以及涂层的制备技术,重点阐述了采用激光熔覆技术制备生物涂层的研究现状以及本课题组的研究进展,指出了目前研究中存在的不足,并展望了生物涂层今后的研究和发展趋势。     

无细胞百日咳疫苗血清学效价检测方法的建立及适用性的初步验证

目的建立无细胞百日咳疫苗血清学效价检测方法(PSPT),并对其适用性进行初步验证。方法采用纯化的百日咳毒素(PT)和丝状血凝素(FHA)包被酶标板,以羊抗鼠IgG酶标抗体为指示抗体,建立检测小鼠抗PT抗体和抗FHA抗体的间接ELISA法,并对该方法进行初步验证。在此基础上建立PSPT法,并与MICA法进行相关性分析。结果建立了小鼠抗PT抗体ELISA和抗FHA抗体ELISA,标准曲线线性范围内R≥0.99;经验证,两系统与无关抗体之间均无交叉反应;检测限度分别为93.7500和59.0625mEU/ml,检测限量分别为100和70mEU/ml。将10批无细胞百日咳原液分别以PSPT法和MICA法进行效价测定,两者呈正相关,两种方法检测结果差异无统计学意义,且PSPT法比MICA法重复性更好。结论抗PT抗体ELISA和抗FHA抗体ELISA灵敏度高,准确性及精密性均较好,在此基础上建立起来的PSPT法有望替代MICA法,用于检测无细胞百日咳疫苗的效价。     

L-精氨酸生产菌株FHA0055的选育研究

以北京棒杆菌（Corynebacterium pekinense）AS1.299为出发菌株,经复合诱变处理,L-精氨酸结构类似物平板进行抗性筛选,获得了一株L-精氨酸结构类似物抗性菌株FHA0055（D-Argr,SMCr,L-HAr）,在糖含量为10%的培养基中,前期30℃,后期32℃,120r/min摇瓶发酵76 h,产L-精氨酸13.25 g/L,较出发菌株提高了140.6%.     

甲异羟肟酸-硝酸辐解产生的H2和CO

甲异羟肟酸(FHA)是有望用于乏燃料后处理的新型无盐络合剂.用5(A)分子筛填充柱与热导池检测器(TCD)联用的气相色谱法研究了HNO_3-0.2 mol/L FHA辐解产生的H_2和CO.H_2的分析是以Ar作载气,柱温为85 ℃,TCD温度为120 ℃; CO的分析是以H_2作载气,柱温为50 ℃, TCD温度为80 ℃.研究结果表明,H_2的体积分数随剂量的增加而增大,随HNO_3浓度的增大而减小;CO只有在剂量很高时才产生,且其体积分数远比H_2低,CO的体积分数随剂量的增加而增加.当c(HNO_3)≤0.5 mol/L时,CO体积分数低于0.2 mol/L FHA水溶液辐解产生的CO,但当c(HNO_3)≥1.0 mol/L时,CO的体积分数大于0.2 mol/L FHA水溶液辐解产生的CO, 且CO体积分数随c(HNO_3)的增大而增大.     

FHA的热物性能及生物活性研究

采用沉淀-煅烧法制备了F掺杂HA的FHA(Ca10(PO4)6(OH)2-2xF2x,0≤x≤1)粉末。通过X射线衍射(XRD)、热重分析(TG)、高温膨胀仪,扫描电镜(SEM),能谱仪(EDS)以及模拟体液浸泡实验研究了F掺杂对FHA高温热稳定性,高温烧结性能,热膨胀系数和生物活性的影响。结果表明,F掺杂能够提高FHA的高温热稳定性,且随F掺杂量增加,其稳定性逐渐提高;少量F(x=0.25)掺杂提高了HA基体的烧结致密度,随F含量增加(x0.25),烧结致密度下降;F掺杂能降低FHA高温热膨胀系数(CET),随着F含量的增加,FHA的CET值减小。类骨磷灰石在块体表面的生长能力为FHAHAFA,其中x=0.5和0.75的FHA具有最好的生物活性。     

LLC谐振半桥变换器的设计

LLC谐振半桥变换器可以在全电压范围内、全负载条件下使得初级端 MOSFET实现ZVS（零电压开关）,次级整流二极管实现ZCS（零电流开关）,减少了开关损耗,大大提高了效率。而且在输入电压和负载范围变化比较大的情况下,其开关频率变化较小,有利于主参数的设计。这种变换器通常应用在高频功率变换领域。文中首先使用 FHA（基波近似原理）进行 LLC谐振半桥变换器的建模,然后分析了如何对变换器中的电气参数进行选择,最后设计了一个工作在70~150 kHz频率下300 W的 LLC谐振变换器。