甘草次酸修饰海藻酸钠纳米给药系统的肝靶向性评估

通过EDC/NHS偶联反应将疏水性肝靶向小分子甘草次酸(GA)连接到天然多糖海藻酸钠(ALG)上,制备了具有双亲性肝靶向药物载体材料(GA-ALG).采用乳化法对广谱抗癌药物阿霉素(DOX)进行包载,得到肝靶向载药纳米粒子( DOX/GA-ALG NPs).利用单光子发射型计算机断层成像技术(SPECT)和药物体内分布...     

一种基于边缘特征的亚像素投影配准算法

为了提高红外图像配准准确度,充分利用图像的边缘信息,结合线性插值,对原有的投影算法引入新的图像相似性评价函数——均方误差函数(Mean Sequare Erron,MSE),提出了基于边缘特征的亚像素投影配准算法.提取图像边缘特征明显的部分做配准能提高匹配概率,引入积分投影能有效降低算法的计算复杂度.算法中还运用了线性插值,使配准准确度达到亚像素级水平.     

铁(Ⅱ)和钴(Ⅱ)与巴比妥酸-NO2-显色反应的研究及应用

在碱性介质中,铁(Ⅱ)和钴(Ⅱ)可与巴比妥酸(BA)-NO2-体系反应,分别形成一种稳定的兰色和黄色配合物,铁(Ⅱ)配合物分别在波长630 nm和350 nm具有吸收峰,钴(Ⅱ)配合物只有一个吸收峰位于365 nm波长处,体系的吸光度AFe630、AFe365和ACo365与铁、钴含量在一定的范围内呈良好的线性关系,且...     

Surface Emitting Distributed Feedback Quantum Cascade Laser around 8.3 μm

We demonstrate surface emitting distributed feedback quantum cascade lasers emitting at wavelengths from 8.1 μm at 90 K to 8.4 μm at 210 K. The second？order metalized grating is carefully designed using a modified coupled-mode theory and fabricated by contact lithography. The devices show single mode behavior with a side mode suppression ratio above 18 dB at all working temperatures. At 90 K, the device emits an optical power of 101 mW from the surface and 199 mW from the edge. In addition, a double-lobe far-field pattern with a separation of 2.2° is obtained in the direction along the waveguide.     

Design of surface emitting distributed feedback quantum cascade laser with single-lobe far-field pattern and high outcoupling efficiency

A 7.8-$\mu $m surface emitting second-order distributed feedback quantum cascade laser (DFB QCL) structure with metallized surface grating is studied. The modal property of this structure is described by utilizing coupled-mode theory where the coupling coefficients are derived from exact Floquet--Bloch solutions of infinite periodic structure. Based on this theory, the influence of waveguide structure and grating topography as well as device length on the laser performance is numerically investigated. The optimized surface emitting second-order DFB QCL structure design exhibits a high surface outcoupling efficiency of 22{\%} and a low threshold gain of 10~cm$^{ - 1}$. Using a {$\pi $} phase-shift in the centre of the grating, a high-quality single-lobe far-field radiation pattern is obtained.     

基于海藻酸钠衍生物的肝靶向纳米前药的构建及抗肿瘤活性研究

利用寡聚乙二醇(mOEG)修饰海藻酸钠(ALG), 有效降低了ALG的黏度, 提高了其对疏水性肝靶向配体甘草次酸(GA)的负载量. 结果表明, 靶向材料(GA-ALG-mOEG)的GA负载量为11.8%, 是对照组(GA-ALG)的1.97倍. 在此基础上, 以物理交联的方式引入pH响应的阿霉素前药(DOX-ALG-mOEG), 制备了肝靶向纳米前药(DOX-ALG-mOEG/GA-ALG-mOEG NPs). 细胞实验及抑瘤实验结果表明, 该前药较对照组(DOX-ALG/GA-ALG NPs)具有更高的肝靶向性和药物利用率, 其对肝癌细胞的半致死率浓度(IC₅₀)为58.1 ng/mL, 是对照组(IC₅₀=141.7 ng/mL)的41%; 动物实验结果显示, 该前药的抑瘤率达到了88.4%, 比对照组提高了11.5%.