Evaluation of an oral carrier system in rats: bioavailability and gastrointestinal absorption properties of curcumin encapsulated PBCA nanoparticles

A new oral delivery system, polybutylcyanoacrylate nanoparticles (PBCNs), was introduced to improve the oral bioavailability of curcumin (CUR), a poorly soluble drug. The formulation was optimized by orthogonal design and the optimal PBCNs loading CUR exhibited a spherical shape under transmission electron microscopy with a range of 40?C400?nm. Physicochemical state of CUR in PBCN was investigated by X-ray diffraction and the possible structure changes occurring in CUR after conjugating with polybutylcyanoacrylate were studied with FTIR. The results indicated that CUR in PBCN was in a non-crystalline state and CUR was encapsulated in PBCN without chemical reaction. The oral pharmacokinetic study was conducted in rats and the relative bioavailability of CUR encapsulated PBCNs to the crude CUR was more than 800%. The in situ absorption experiment in rat intestine indicated the absorption was first order with passive diffusion mechanism. The absorption results in various segments of intestine showed that the main absorption sites were ileum and colon. It can be concluded that PBCNs as an oral carrier can significantly improve the oral absorption of a poorly soluble drug.     

夹套冰温库内流场的数值模拟

随着计算机技术的飞速发展,计算流体力学(CFD)越来越广泛地应用于各个领域。通过CFD对复杂流动问题进行研究,能够较精确地反映流场的流动情况。利用CFD技术对夹套冰温库内的流场进行了稳态数值模拟,分析了夹套冰温库内流场的分布情况,讨论了该库体结构下不同送风速度对库内流场均匀性的影响。研究表明,具有夹套结构的冰温库,库内流场分布均匀,采用顶部静压箱送风,底部四周回风的送回风方式,能够使库内形成自上而下的均匀活塞流,不同送风速度对冰温库内流场的影响很小。研究结果证明数值模拟能较好地反映现实情况。     

Solution-combustion synthesis of Tb-doped Y3Al5O12 nanoparticles

Nano-sized YAG:Tb powder phosphors were prepared by a solution-combustion method, using the general inorganic salts as starting materials. The X-ray diffraction (XRD) measurements showed that the precursor can be well-crystallized at 900 °C. As-prepared particles have sizes mostly in the range between 30 and 100 nm as obtained by scanning electron microscope (SEM) and transition electron microscope (TEM). Selected area electron diffraction (SAED) patterns proved that the larger particles are monocrystalline. The effects of annealing temperature and Tb-doping concentration on the luminescence intensity were studied.     

Low-loss, compact waveguiding with TE mode in metal/dielectric waveguides for planar lightwave circuit

We propose a low-loss metal/dielectric waveguide for compact planar lightwave circuit. The basic waveguide structure is a metal-defined high-index-contrast strip waveguide based on silicon/silica. As the guide is designed for TE single mode waveguiding, extremely low propagation loss (e.g. <0.04 dB/cm), very low bend loss (e.g. 0.0043 dB/90°-turn) and small waveguide pitch of zero-crosstalk are theoretically achievable, and can be further improved by compromising with component size and density. Examples of multi-bends and device integration are demonstrated with numerical simulations. The proposal is compatible with silicon technology and appealing for development of silicon-based planar lightwave circuit.     

Incoherently coupled Hermite-Gaussian breather and soliton pairs in strongly nonlocal nonlinear media

We theoretically investigate the propagation of incoherently coupled Hermite-Gaussian breather and soliton pairs in strongly nonlocal nonlinear media. It is found that multipole-mode soliton pairs with arbitrary different orders of Hermite-Gaussian shape can exist when the total power of two beams equals the critical power and the ratio of the beam widths for the Gaussian part is inversely proportional to the square root of the ratio of the wave numbers. When the total power does not equal the critical power, the Hermite-Gaussian breather pair exists and their beam widths evolve analogously. For general cases where the ratio of the beam widths is arbitrary, soliton-breather pairs or breather-breather pairs can be formed and their beam widths evolve synchronously in-phase or out-of-phase. Numerical simulations directly based on the nonlocal nonlinear Schrödinger equation are conducted for comparison with our theoretical predictions. The numerical stability analysis shows the higher-order Hermite-Gaussian solitons can not be stable for small nonlocality or for some media like liquid crystals.     

In situ functionalized self-assembled monolayer surfaces for selective chemical vapor deposition of copper

Recent studies show that the self-assembled monolayer (SAM) is well suited to control the selectivity of chemical vapor deposition (CVD). Here, we reported the selective CVD for copper on the functionalized SAM surfaces (with -SH, -SS-, and -SO₃H terminal groups). The -SS- and -SO₃H terminal group surfaces were obtained through in situ chemical transformation of -SH terminal group surface of a 3-mercaptopropyltrimethoxysilane-SAM (MPTMS-SAM). As a result, the -SS- terminal group surface reduces copper deposition and the -SO₃H terminal group surface enhances copper deposition comparing to the -SH terminal group surface. In addition, the MPTMS-SAM was irradiated by UV-light through a photo mask to prepare SH-group and OH-group regions. Then, copper films were deposited only on the SH-group region of the substrate in chemical vapor deposition. Finally, patterns of copper films were formed in the way of UV-light irradiation. These results are expected for use of selective deposition of copper metallization patterns in IC manufacturing processes.     

Synchrotron radiation assistant MOCVD deposition of ZnO films on Si substrate

The growth of ZnO film on Si(1 0 0) substrate has been studied with synchrotron radiation (SR) assisted MOCVD method. The diethylzinc (DEZn) and CO₂ are used as source materials, while Nitrogen is employed as a carrier gas for DEZn. With the assistance of SR the ZnO film can be deposited even at room temperature. XRD, SEM and photoluminescence (PL) studies show that the crystal quality of ZnO films grown with the assistance of SR is higher than that of those without SR assistance. The growth mechanism of ZnO film with the SR assistant MOCVD system is primarily discussed.     

LaB6场发射阵列牺牲层制备工艺

 分析了传统牺牲层材料铝在制备LaB6场发射阵列时存在的问题,利用溅射及热蒸发工艺依次制备铝膜和氧化锌膜,制备出了一种新型的牺牲层——ZnO-Al复合牺牲层,并对所制备的阵列进行了测试。实验结果表明：ZnO-Al复合牺牲层能够有效地解决电化学腐蚀的问题,所制备出的LaB₆场发射阵列尖锥保持了完好的形貌,其发射特性也达到了最初制备场发射阵列的要求,说明ZnO-Al复合牺牲层是作为LaB₆场发射阵列牺牲层的理想材料。     

高效液相色谱法同时测定心可舒胶囊中齐墩果酸和熊果酸

建立高效液相色谱法同时测定心可舒胶囊中齐墩果酸和熊果酸的含量。采用HypersiL ODSC₁₈（4.6mm×250mm,5μm）色谱柱;流动相:甲醇-乙腈-水=79:5:16（V/V/V）;柱温:30℃;流速:1mL/min;检测波长:210nm。齐墩果酸在2.04—81.60μg/mL浓度范围内线性关系良好（r=0.9998）,熊果酸在5.00—80.00μg/mL浓度范围内线性关系良好（r=0.9998）,齐墩果酸的平均回收率为100.54%,RSD为1.56%,熊果酸的平均回收率为101.10%,RSD为1.13%。该法简单、准确、快捷,可用于心可舒胶囊中齐墩果酸和熊果酸的含量测定。     

利用非线性传输线产生高功率射频场

根据孤立子理论,分析了利用变容非线性传输线产生射频场的机理。利用电路仿真方法系统地研究了影响射频场产生的相关参数,发现电感和零压电容越小、输入电压越大,射频场的频率越高;电容的非线性率越大,射频场的峰值电压越高、高频成分越多。并在此基础上,仿真设计了能产生峰值功率为0.8 GW、主频为19.42 MHz射频场的非线性传输线。