黄颡鱼成鱼池塘养殖试验

针对目前大众对高档水产品需求旺盛的实际,通过选择对黄颡鱼成鱼的养殖试验,总结了黄颡鱼成鱼在养殖过程中水质管理、饲料投喂和病害防治等方面的经验。提出黄颡鱼成鱼养殖完全可以在山西省得以推广。     

Cooperative, heparan sulfate-dependent cellular uptake of dimeric guanidinoglycosides

Oligoarginine and guanidinium-rich molecular transporters have been shown to facilitate the intracellular delivery of a diverse range of biologically relevant cargos. Several such transporters have been suggested to interact with cell-surface heparan sulfate proteoglycans as part of their cell-entry pathway. Unlike for other guanidinium-rich transporters, the cellular uptake of guanidinoglycosides at nanomolar concentrations is exclusively heparan sulfate dependent. As distinct cells differ in their expression levels and/or the composition of cell-surface heparan sulfate proteoglycans, one might be able to exploit such differences to selectively target certain cell types. To systematically investigate the nature of their cell-surface interactions, monomeric and dimeric guanidinoglycosides were synthesized by using neomycin, paromomycin, and tobramycin as scaffolds. These transporters differ in the number and 3D arrangement of their guanidinium groups. Their cellular uptake was measured by flow cytometry in wild-type and mutant Chinese hamster ovary cells after the corresponding fluorescent streptavidin-phycoerythrin-Cy5 conjugates had been generated. All derivatives showed negligible uptake in mutant cells lacking heparan sulfate. Decreasing the number of guanidinium groups diminished uptake, but the three dimensional arrangement of these groups was less important for cellular delivery. Whereas conjugates prepared with the monomeric carriers showed significantly reduced uptake in mutant cells expressing heparan sulfate chains with altered patterns of sulfation, conjugates prepared with the dimeric guanidinoglycosides could overcome this deficiency and maintain high levels of uptake in such deficient cells. This finding suggests that cellular uptake depends on the valency of the transporter and both the content and arrangement of the sulfate groups on the cell-surface receptors. Competition studies with chemically desulfated or carboxy-reduced heparin derivatives corroborated these observations. Taken together, these findings show that increasing the valency of the transporters retains heparan sulfate specificity and provides reagents that could distinguish different cell types based on the specific composition of their cell-surface heparan sulfate proteoglycans.     

An efficient paradigm for wavelet‐based image processing using cellular neural networks

We propose a novel paradigm for cellular neural networks (CNNs), which enables the user to simultaneously calculate up to four subband images and to implement the integrated wavelet decomposition and a subsequent function into a single CNN. Two sets of experiments were designated to test the performance of the paradigm. In the first set of experiments, the effects of seven different wavelet filters and five feature extractors were studied in the extraction of critical features from the down‐sampled low‐low subband image using the paradigm. Among them, the combination of DB53 wavelet filter and the r=2 halftoning processor was determined to be most appropriate for low‐resolution applications. The second set of experiments demonstrated the capacity of the paradigm in the extraction of features from multi‐subband images. CNN edge detectors were embedded in a two‐subband digital wavelet transformation processor to extract the horizontal and vertical line features from the LH and HL subband images, respectively. A CNN logic OR operator proceeds to combine the results from the two subband line‐edge detectors. The proposed edge detector is capable of delineating more subtle details than using typical CNN edge detector alone, and is more robust in dealing with low‐contrast images than traditional edge detectors. The results demonstrate the proposed paradigm as a powerful and efficient scheme for image processing using CNN. Copyright © 2008 John Wiley & Sons, Ltd.     

TOA模式下消除观测站位置误差的移动台定位新方法

针对移动台定位中各观测站位置存在随机测量误差的情况,提出了一种结合TOA测量值与观测站位置坐标测量值,建立统一观测方程实现精确定位的方法。该方法通过Taylor级数展开实现观测方程的线性化,采用加权最小二乘进行多次迭代运算,完成对移动台和观测站位置坐标的同时估计。通过不同观测站数量条件下的仿真分析,该方法的定位性能逼近CRLB,且不论观测站几何布局的优劣,在正确选取初始值保证迭代收敛的条件下,定位性能明显优于传统的定位解算方法。     

Amphibious Territories

Since 2005, when Hurricane Katrina wreaked havoc on the Gulf Coast and New Orleans, our polarised perception of land and water has been irrevocably shifted by the failure of static levee flood-control systems. Ila Berman explains how a more fluid geographical approach to land and water, which places an emphasis on continuous mutable ecologies, is key to a more sustainable future. She describes four experimental projects that are ground-breaking in their treatment of the relationship between the aquatic and terra firma. Copyright © 2010 John Wiley & Sons, Ltd.     

Urban Interactive

Valentina Croci profiles the work of entertainment design office Area/Code which foregrounds urban locations in its games. As Croci explains the approach of this NewYork-based partnership, which delivers sat nav-inspired gaming to the mobile phone, demonstrates an inherent understanding of the importance of the physical in enhancing the imaginary. Copyright © 2010 John Wiley & Sons, Ltd.     

Small-sized carbon nanohorns enabling cellular uptake control

Carbon nanotubes perform well in preclinical tests for drug delivery and diagnostic imaging, but controlling the size at less than 100 nm to avoid nonspecific uptake by reticuloendothelial systems while targeting delivery to cells of interest via receptor-mediated endocytosis is difficult, which currently limits their widespread use. Herein, 20-50-nm graphene tubules, small-sized single-walled carbon nanohorns (S-SWNHs), are obtained with a yield of 20% or higher by an oxidative exfoliation of 100 nm pristine SWNH aggregates. S-SWNHs are highly hydrophilic and remarkably resistant to cellular uptake by macrophages (RAW 264.7 cells), tumor cells (HeLa or KB), or normal cells (FHs 173We). The nonstimulatory property to cell membranes therefore makes cellular uptake control of S-SWNHs by functionalization easy. By attaching phospholipid polyethylene glycol, the cellular internalization of S-SWNHs is almost completely inhibited in RAW 264.7 macrophages. When functionalized with tumor-targeting folic acid (FA), FA-S-SWNHs are taken up by FA receptor-overexpressing KB cells but not by normal human embryonic cells (FHs 173We), which do not express the FA receptor. With a high rate of stealth and targeting in vitro, S-SWNHs are one of the most promising nanoparticles for medical use.     

A New Approach to Assess Gold Nanoparticle Uptake by Mammalian Cells: Combining Optical Dark‐Field and Transmission Electron Microscopy

Toxicological effects of nanoparticles are associated with their internalization into cells. Hence, there is a strong need for techniques revealing the interaction between particles and cells as well as quantifying the uptake at the same time. For that reason, herein optical dark‐field microscopy is used in conjunction with transmission electron microscopy to investigate the uptake of gold nanoparticles into epithelial cells with respect to shape, stabilizing agent, and surface charge. The number of internalized particles is strongly dependent on the stabilizing agent, but not on the particle shape. A test of metabolic activity shows no direct correlation with the number of internalized particles. Therefore, particle properties besides coating and shape are suspected to contribute to the observed toxicity.     

Shear Modulus Determination of Cuboid Metallic Open‐Lattice Cellular Structures by Analytical,Numerical and Homogenisation Methods

Abstract: The shear response of irregular open‐lattice cellular cores made of interconnected metallic struts is analysed, and the core shear modulus in the three material principal directions is derived. The analytical approach is based on the technical beam theory, which is used for the determination of the unit‐cell response under complex loading. The influence of the strut geometrical parameters and unit‐cell shape and size on the cellular core shear stiffness is determined. The analytical determination of the unit‐cell properties is successfully validated by a reference numerical model of the unit cell, which is developed for comparison purposes. Furthermore, the homogenisation principles are applied to the prediction of the shear response of a core block structure comprising a high number of unit cells, for which experimental results were available; the comparison revealed that the experimental results coincide well with the results obtained from the homogenised model.     

软质泡沫聚合材料拉伸强度测定结果的不确定度评定

依据GB／T6344--2008测定了聚氨酯软泡的拉伸强度,并对拉伸强度测定结果的不确定度进行了分析评定。结果表明：该聚氨酯软泡的拉伸强度为142kPa时,测定结果的扩展不确定度为2kPa,包含因子k=2。