Targeted blue nanoparticles as photoacoustic contrast agent for brain tumor delineation

Distinguishing a tumor from non-neoplastic tissue is a challenging task during cancer surgery. Several attempts have been made to use visible or fluorescent agents to aid in the visualization of a tumor during surgery. We describe a novel method to delineate brain tumors, using a highly sensitive photoacoustic imaging technique that is enhanced by tumor-targeting blue nanoparticles serving as a contrast agent. Experiments on phantoms and on rat brains, ex vivo, demonstrate the high sensitivity of photoacoustic imaging in delineating tumors containing contrast agent at a concentration much lower than needed for visualization by the naked eye. The limit of detection of the system for the nanoparticles is about 0.77 μg/mL in water (equivalent to 0.84 μmol/L Coomassie Blue dye). The present exploratory study suggests that photoacoustic imaging, when used with strongly optical absorbing contrast agents, could facilitate cancer surgery intraoperatively by revealing the distribution and extent of the tumor.      

常规工艺中消毒副产物前体物季节变化研究

对某给水厂进行了一个水文年的月度监测,重点分析了各工艺段出水的三卤甲烷和卤乙酸前体物浓度变化。结果表明,对消毒副产物前体物控制起关键作用的是沉淀工艺和过滤工艺。沉淀工艺对消毒副产物前体物的去除受到混凝效果的影响,随季节有较大波动。过滤工艺出水中三卤甲烷、卤乙酸前体物全年都呈现增长。过滤工艺出水中三卤甲烷前体物的增加明显高于卤乙酸前体物。     

Surface- and bulk- micromachined two-dimensional scanner driven by angular vertical comb actuators

In this paper, we present the design, fabrication, and measurements of a two-dimensional (2-D) optical scanner with electrostatic angular vertical comb (AVC) actuators. The scanner is realized by combining a foundry-based surface-micromachining process (Multi-User MEMS Processes-MUMPs) with a three-mask deep-reactive ion-etching (DRIE) postfabrication process. The surface-micromachining provides versatile mechanical design and electrical interconnect while the bulk micromachining offers high-aspect ratio structures leading to flat mirrors and high-force, large-displacement actuators. The scanner achieves dc mechanical scanning ranges of /spl plusmn/6.2/spl deg/ (at 55 Vdc) and /spl plusmn/4.1/spl deg/ (at 50 Vdc) for the inner and outer gimbals, respectively. The resonant frequencies are 315 and 144 Hz for the inner and the outer axes, respectively. The 1-mm-diameter mirror has a radius of curvature of over 50 cm. [1454].     

基于改进Hough变换的图像线段特征提取

为了从复杂背景中提取欲识别的目标,提出一种基于改进Hough变换的图像线段特征提取方法.针对传统Hough变换的局限性,在经典算法的基础上增加了全局阈值与局部阈值结合去除虚假尖峰,利用动态分组原则确定线段的端点,融合端点邻近的线段等改进算法.实验表明,该方法不但可以识别简单背景中的规则几何图形,还可以有效地提取复杂背景中真实目标的线段特征.     

基于小波多分辨率分析的混沌去噪研究

基于小波多分辨率分析的思想,提出一种降低混沌信号噪声的方法.首先对一个混沌时间序列进行小波分析,得到信号在各个尺度上的不同特性;再对各个高频细节信号进行二次小波去噪;最后对二次小波去噪后的信号进行线性叠加,达到提取真实信号的目的.分别对Rossler系统产生的混沌序列和黄河年径流量混沌序列进行了仿真研究,结果表明了该方法的有效性.     

Lipase from Penicillium camembertii KCCM 11268: Optimization of solid state fermentation and application to biodiesel production

Lipase was produced by Penicillium camembertii KCCM 11268 under solid state fermentation (SSF), and the production process was optimized by using statistical experimental designs. The initial moisture content, cultivation time, inoculum size and concentration of basal medium were considered as the factors of optimum conditions for SSF. P. Camembertii KCCM 11268 was cultivated in SSF using wheat bran as the substrate for lipase production. Under the optimized condition, lipase activity was reached around 7.8 U/ml after eight days fermentation. To partially purify the lipase, ammonium sulfate (80% saturation) was added to the crude lipase solution and concentrated using a diafiltration (VIVAFLOW 50). The concentrated lipase solution from P. Camembertii KCCM 11268 (PCL) was immobilized on silica gel by cross-linking method. Also, PCL was mixed with a commercial lipase solution from Candida rugosa (CRL), and this mixture was co-immobilized on silica gel. The immobilized and co-immobilized lipase activities were 1150.1 and 7924.8 U/g matrix, respectively. Palm oil and methanol were used as substrates and 1mmol of methanol was added every 1.5 h and 2 times during biodiesel production. The reaction was carried out at temperatures of 30, 40, 50, 60 and 70 °C. The maximum biodiesel conversion by co-immobilized lipase was 99% after 5 h at 50 °C.     

Improved reutilization of industrial crude lysine to 1,5-diaminopentane by enzymatic decarboxylation using various detergents and organic solvents

World-wide production of l-lysine has rapidly increased in recent years. In the industrial scale production, it is cost effective to minimize waste as many waste materials are generated during downstream processing. Therefore, the conversion of crude lysine to a more valuable product reduces waste emission. In this study, 1,5-diaminopentane (DAP, trivial name: cadaverine) was produced by l-lysine decarboxylation using Hafnia alvei. The conditions of enzymatic reaction were determined. In particular, the addition of specific detergent (Brij 56) was significantly affected in the bioconversion system. Addition of hydrophobic organic solvent improved the mixing of the reactants. Finally, an industrial crude form of lysine served as a substrate. The DAP conversion by analytical, feed and industrial crude l-lysine was 93.9%, 90.3%, and 63.8%, respectively.     

铌、钒、钛在微合金钢中的作用

微合金化元素Nb、V、Ti在钢中的作用,主要表现在在热加工过程中抑制奥氏体的形变再结晶并阻止其晶粒的长大,并通过它们的碳氮化合物的应变诱导析出,对钢进行沉淀强化。这3个元素虽然都是通过细化晶粒和沉淀强化来提高强度,但它们在钢中的作用机理及强化程度并不同,Nb在钢中具有最强的晶粒细化强化效果,而V在钢中具有最强的沉淀强化效果,Ti则介于Nb和V两者之间。