Flash nanoprecipitation with Gd(III)‐based metallosurfactants to fabricate polylactic acid nanoparticles as highly efficient contrast agents for magnetic resonance imaging

Polylactic acid (PLA) nanoparticles coated with Gd(III)‐based metallosurfactants (MS) are prepared using a simple and rapid one‐step method, flash nanoprecipitation (FNP), for magnetic resonance imaging (MRI) applications. By co‐assembling the Gd(III)‐based MS and an amphiphilic polymer, methoxy poly(ethylene glycol)‐b‐poly(?‐caprolactone) (mPEG‐b‐PCL), PLA cores were rapidly encapsulated to form biocompatible T₁ contrast agents with tunable particle size and narrow size distribution. The hydrophobic property of Gd(III)‐based MS were finely tuned to achieve their high loading efficiency. The size of the nanoparticles was easily controlled by tuning the stream velocity, Reynolds number and the amount of the amphiphilic block copolymer during the FNP process. Under the optimized condition, the relaxivity of the nanoparticles was achieved up to 35.39 mM^?1 s^?1 (at 1.5 T), which is over 8 times of clinically used MRI contrast agents, demonstrating the potential application for MR imaging.     

New Wine in Old Bottles: Prolonging Room‐Temperature Phosphorescence of Crown Ethers by Supramolecular Interactions

Supramolecular macrocyclic hosts have long been used in smart materials. However, their triplet emission and regulation at crystal level is rarely studied. Herein, ultralong and universal room‐temperature phosphorescence (RTP) is reported for traditional crown ethers. A supramolecular strategy involving chain length adjustment and morphological locking through complexation with K⁺ was explored as a general method to tune the phosphorescence lifetime in the solid state. A maximum 10‐fold increase of lifetime after complex formation accompanied with by invisible to visible phosphorescence was achieved. A deep encryption based on this activated RTP strategy was also facilely fabricated. This work thus opens a new world for supramolecular macrocycles and their intrinsic guest responsiveness offers a new avenue for versatile smart luminescent materials.     

白蛋白/透明质酸纳米颗粒制备及递送顺铂效果

利用白蛋白模板法,以白蛋白、酰肼化透明质酸和醛基化透明质酸为原料,制备出了白蛋白/透明质酸(B-HA)纳米载体,其可通过配位作用装载顺铂(Cis)得到B-HA/Cis纳米药物.利用FT-IR光谱、1H-NMR谱、透射电子显微镜和电感耦合等离子体-质谱(ICP-MS)等手段表征了B-HA纳米载体的化学结构和B-HA/Ci...     

牛顿第三定律的研究

1引言 牛顿第三定律是牛顿力学的重要基础之一.在物理教学中,往往会碰到牛顿第三定律不能给予正确的解释的例子,如两个运动电荷之间的相互作用.下面我们就这一问题进行一些探讨.     

钯卟啉室温燐光氧传感器的研究

以Dowex 5 0× 2 1 0 0树脂为载体固定四 (三甲氨基苯基 )钯卟啉 (Pd TAPP) ,利用其光被氧猝灭的特性 ,采用流动注射分析 (FIA)技术 ,制成氧传感器。该方法响应快 (响应时间从氮气到氧气为 1 8s,反之为86s) ,灵敏度高 (I0 I1 0 0 值为 5 .6) ,检测限可达 0 .0 9% (V V)。     

The investigation of compound YAG phase-conjugate resonator

How to improve the quality of output beam of phase-conjugation cavity is a problem. And there are a few reports on how to improve the quality of output beam mode [1]. On this paper, the output characteristic of compound phase-conjugate resonator was reported. The experiment results indicated that it has high output energy and excellent mode. The output energy is 7.4 mJ, and the width of it is about 15 ns. The results of pulse widths and output energies and beam profiles were given and it indicates that using the compound cavity is a useful and easy method to improve the quality of beam mode.     

N(4S)+CH3X(X=Cl、Br)反应机理的理论研究

利用abinitio方法对N(4S)+CH3X(X=Cl、Br)反应进行了理论研究,在MP2/6311+G(d,p)水平上优化得到了反应途径上的反应物、过渡态和产物的几何构型和谐振频率,在MP2/6311++G(3df,2p)和QCISD(T)/6311+G(d,p)水平上进行单点能计算,并用G2MP2方法计算了所有物种的能量.计算结果表明,反应存在三条反应通道:H抽提反应通道a、Cl或Br抽提反应通道b和替代反应通道c.对于N(4S)+CH3Cl反应,a反应通道是主反应通道,b和c反应通道在反应中有少量贡献.对于N(4S)+CH3Br反应,a反应通道是主反应通道,b和c反应通道在反应中有一定的贡献.