Chemical mediation of egg capsule deposition by mud snails

Mud snails (Ilyanassa obsoleta = Nassarius obsoletus = Nassa obsoleta) deposit eggs in protective capsules on hard substrata in soft bottom environments. We studied sites of egg capsule deposition and snail movement responses to odors to determine if chemoreception plays a role in deposition site selection. From results of field surveys, laboratory experiments, and field experiments, we conclude that mud snails use chemoreception for capsule deposition. Attractive odors originate from mud snail and whelk egg capsules and from living bivalves. Evidence for attractive odors from conspecifics is equivocal. Capsules are deposited on living odor sources and nearby hard substrates. We hypothesize that deposition of capsules on living substrates increases the likelihood that embryos will survive by decreasing the chance of smothering of embryos by sediments.     

环氧复合材料低温固化剂研究进展

低温固化(固化温度低于100℃)可获得高尺寸稳定性、低成本、力学性能优良的环氧复合材料,室温储存期长的低温固化剂体系是低温固化环氧复合材料的关键。重点探讨了微胶囊型、潜伏性以及其它改性环氧低温固化剂,展望了其未来前景及发展方向。     

基于超像素分割的无线内窥镜出血图像检测

将图像形态学处理和计算机辅助诊断方法应用于无线内窥镜出血图像检测。在对无线内窥镜图像进行形态学处理和超像素分割的基础上,提出红色纯度特征,应用最小二乘支持向量机分类器对分割后的图像进行分类。试验结果表明,该方法能够有效地检测无线内窥镜图像中的出血区域,敏感性、特异性和准确率分别达到了99%、94%和95%,可以作为临床医生的辅助诊断工具。     

基于明暗信息的胶囊内镜图像三维形状恢复

利用明暗恢复形状技术,将视频胶囊内镜二维图像的明暗信息重构小肠内腔表面的三维场景信息。针对传统的明暗恢复形状技术的约束条件,提出了一种针对胶囊内镜图像的预处理方法,利用预处理后的图像恢复出更为平滑的视觉场景,同时保留被检查对象的结构信息。基于临床数据的实验结果表明,三维形状恢复技术可以增强胶囊内镜视频的可读性,提高小肠疾病的诊断准确率。     

A 2.4GHz Low Power ASK Transmitter for Wireless Capsule Endoscope Applications

提出了一种应用于无线内窥镜系统的2.4GHz低功耗ASK发射机.为了获得高的数据传输速率,采用了基于混频器的直接上变换发射机结构.为了节省功耗,提出了一种基于电流复用技术的伪差分堆栈结构的A类功放.低功耗发射机由两部分组成:基于恒幅度锁相环(PLL)的20MHz的ASK基带调制器和直接上变换的射频电路.该设计已经采用TSMC 0.25μm CMOS工艺实现并进行了验证.测试结果表明,发射数据速率为1Mbps时,发射机的输出功率为-23.217dBm.采用单2.5V的电源供电下,低功耗发射机消耗的电流约为3.17mA.     

Some key technics of drop tower experiment device of National Microgravity Laboratory (China) (NMLC)

Microgravity science and application pro-ject is a very important part of Chinese space effort. This area has been very active along with the international space activities in re-cent years and has got many important re-sults. The completion and running of the international space station will further pro-mote the research activities in the area of microgravity science and application. The National Microgravity Laboratory (China) (NMLC) was established in the mid-dle of the 1990s. Drop towe…     

新型充Ar靶丸设计

从惯性约束聚变实验物理诊断需求出发,提出并分析了利用聚碳硅烷空心微球作为DT燃料容器实现扩散法充氩的可行性。初步实验研究表明,聚碳硅烷微球有望替代玻璃微球作为DT燃料容器用于内爆物理研究。     

快速有效的半自动组织分割技术

针对医学可视化和虚拟内窥镜技术中的组织分割问题，提出边界模型和局部特征结构相结合的半自动解决方法，通过给定的特定体素点，结合边界模型找出特定组织的内部、外部体素，对边界体素计算汉森矩阵的特征值并按其特征结构进行分割．该方法只需要计算边界体素汉森矩阵的特征值，能够快速、有效地实现单一组织的分割．     

一种结肠靶向给药胶囊的研究

以1号胃溶空心胶囊为母体,以聚丙烯酸树酯类高分子材料为包衣材料,以愈创木酚甘油醚为模型药物,对不同包衣厚度的结肠溶肠溶胶囊进行了体内外参数研究,结果表明包衣厚度为60～100μm的该肠溶胶囊较为理想.该厚度的胶囊在pH≥7.0的条件下,崩解后所释放出的颗粒在结肠的分布广泛,个体差异小,50%胶囊到达人体回盲部和结肠的时间分别约为4h和5h,达到了结肠靶向给药的设计要求.     

Effects of powder flow properties on capsule filling weight uniformity

Filling capsules with the right amount of powder ingredients is an important quality parameter. The purpose of this study was to develop effective laboratory methods for characterizing flow properties of pharmaceutical powder blends and correlating such properties to weight variability in filled capsules. The methods used for powder flow characterization were bulk and tapped density, gravitational displacement rheometer (GDR) flow index, Freeman Technology V.4 (FT4) powder rheometer compressibility, FT4 basic flow energy (BFE), and cohesion parameters [cohesion, (C) and flow factor (ffc)] measured in a shear cell also using the FT4. Capsules were filled using an MG2-G140 continuous nozzle dosator capsule-filling machine. Powder flow properties were the most predominant factors affecting the weight and weight variability in the filled capsules. Results showed that the weight variability decreased with increasing bulk and tapped density, ffc and BFE, while the weight variability increased with increasing compressibility, cohesion and GDR flow index. Powder flow properties of the final blends were significantly correlated to the final capsule weight and weight variability of the filled capsules.