Effect of chelators and reductants on the mobilization of metals from ambient particulate matter

Ambient urban particulate matter (PM) contains various transition metals. When the PM is inhaled into the lung, not all but some part of metals from the particles might be mobilized to participate in a reaction that can damage various biomolecules, such as DNA and proteins. The dust particle size as well as organic acids may influence the metal mobilization. Thus, the mobilization of the metal from two standard reference materials (SRM; NIST, USA) and urban PM (PM2.5 and PM10) collected in the Seoul area was measured in the presence of artificial or biological chelator with or without reductant. The degree of the mobilization was higher with the artificial or biological chelator than the control with saline. In some cases, a reductant increased the mobilization as much as about 5 times the control without the reductant. Especially, the mobilization of Fe was greatly influenced by the presence of reductants. In general, the degree of the mobilization of the transition metal was higher with PM2.5 than with PM10. Therefore, it is expected that, considering the previously known toxicities of the transition metals, PM2.5 is more damaging to various biomolecules than PM10. The results also suggest that not the total amount but the mobilizable fraction of the metal in the ambient PM should be considered with regard to the toxicity of the urban particulate matter.     

A resource-efficient and scalable wireless mesh routing protocol

By binding logic addresses to the network topology, routing can be carried out without going through route discovery. This eliminates the initial route discovery latency, saves storage space otherwise needed for routing table, and reduces the communication overhead and energy consumption. In this paper, an adaptive block addressing (ABA) scheme is first introduced for logic address assignment as well as network auto-configuration purpose. The scheme takes into account the actual network topology and thus is fully topology-adaptive. Then a distributed link state (DLS) scheme is further proposed and put on top of the block addressing scheme to improve the quality of routes, in terms of hop count or other routing cost metrics used, robustness, and load balancing. The network topology reflected in logic addresses is used as a guideline to tell towards which direction (rather than next hop) a packet should be relayed. The next hop is derived from each relaying node’s local link state table. The routing scheme, named as topology-guided DLS (TDLS) as a whole, scales well with regard to various performance metrics. The ability of TDLS to provide multiple paths also precludes the need for explicit route repair, which is the most complicated part in many wireless routing protocols. While this paper targets low rate wireless mesh personal area networks (LR-WMPANs), including wireless mesh sensor networks (WMSNs), the TDLS itself is a general scheme and can be applied to other non-mobile wireless mesh networks.     

Effect of Conductive Particle Properties on the Reliability of Anisotropic Conductive Film for Chip-on-Glass Applications

This paper describes how the material properties of conductive particles in anisotropic conductive films (ACFs) affect the electrical conductivity and the reliability of ACF interconnections for chip-on-glass (COG) applications. For the conductive particles, Au/Ni-coated polymer particles with a 5-diameter were used. Two different types of conductive particles were characterized with respect to their mechanical and electrical properties, such as ball hardness, recovery behavior, and electrical resistance. In addition, two ACFs were fabricated in the form of a double-layered structure, in which the thickness of the ACF and a nonconductive film (NCF) layer were optimized to have as many conductive particles as possible on the bump after COG bonding. The electrical contact resistance of an ACF interconnection in a COG structure depends mainly on the electrical properties of conductive particles in the ACF. The electrical reliability of an ACF interconnection in a COG structure also depends more on the electrical properties than the mechanical properties of conductive particles under a high-temperature and humid condition. Conductive particles with a lower electrical resistance, higher mechanical hardness, and lower recovery rate show better reliability than conductive particles with a higher electrical resistance, lower mechanical hardness, and higher recovery rate. Cross-sectional scanning electron microscopic (SEM) pictures of a COG interconnection show the deformation of two different conductive particles after the reliability tests. The ACF interconnections in the edge or corner of a driver IC show less reliable joints due to high absorption of moisture.     

An asymptotically exact LMI solution to the robust discretisation of LTI systems with polytopic uncertainties and its application to sampled-data control

In this paper, the problem of robust discretisation of linear time-invariant (LTI) systems with polytopic uncertainties is introduced. More specifically, the main objective is to provide a systematic way to find an approximate discrete-time (DT) model of a continuous-time (CT) plant with uncertainties in polytopic domain. The system matrices of polytopic DT model to be found are expressed as parameter-dependent matrices which are homogeneous polynomials of arbitrary degree with respect to the uncertain variables in the simplex, and is obtained in such a way that the norm between the system matrices and the truncated power series of the exact DT model is minimised while preserving the polytopic structure of the original CT plant. The solution procedures proposed are presented in terms of single-parameter minimisation problems subject to linear matrix inequality (LMI) constraints which are numerically tractable via LMI solvers. Finally, examples are given to show the validity and effectiveness of the proposed techniques.     

A synchronization algorithm for distributed multimedia environments

Network synchronization plays a significant role in transmitting multimedia objects over computer networks. Even packets from a single channel must be synchronized due to the problems in a packet switching environment, such as network jitter, frequency, and time offsets. We present an algorithm that determines the set of packets generated periodically by various participants arriving at a node. The basic advantage of the proposed algorithm is that the receiver estimates the reference times (expected arrival times of the packets) and achieves synchronization, without knowledge of the packet delays. The accuracy is improved and the complexity is reduced by predicting the time/frequency offsets between the clocks at the source and the mixer. The error is calculated by the Chernoff bound, demonstrated by simulation, and shown to be acceptable in practical applications.     

40 GHz Vertical Transition with a Dual‐Mode Cavity for a Low‐Temperature Co‐fired Ceramic Transceiver Module

A new vertical transition between a substrate integrated waveguide in a low‐temperature co‐fired ceramic substrate and an air‐filled standard waveguide is proposed in this paper. A rectangular cavity resonator with closely spaced metallic vias is designed to connect the substrate integrated waveguide to the standard air‐filled waveguide. Physical characteristics of an air‐filled WR‐22 to WR‐22 transition are compared with those of the proposed transition. Simulation and experiment demonstrate that the proposed transition shows a ?1.3 dB insertion loss and 6.2 GHz bandwidth with a 10 dB return loss for the back‐to‐back module. A 40 GHz low‐temperature co‐fired ceramic module with the proposed vertical transition is also implemented. The implemented module is very compact, measuring 57 mm × 28 mm × 3.3 mm.     

Points‐based user interface for character posing

We present a points‐based user interface for character posing. In our method, users insert a number of three‐dimensional (3D) points in a virtual environment. The system performs a linear search of a motion capture database for the best matched pose and then places the pose immediately in the virtual environment to be overlapped with the input points. For a fast and precise distance computation between the input points and the example poses from the database, we developed a closed‐form solution of the 3D points registration problem. To demonstrate the easiness and usability of our approach, we built a motion database including various kinds of human motion and conducted a user study of character posing tasks with non‐expert users. Copyright © 2016 John Wiley & Sons, Ltd.     

A convenience UPLC/PDA method for the quantitative analysis of panaxfuraynes A and B from Panax ginseng

Panaxfurayne A and B, biologically novel tetrahydrofuranic polyacetylene glycosides, were founded from roots of Panax ginseng C. A. Meyer (Araliaceae). To study the contents of panaxfurynes A and B, a quantitative analysis method was developed using ultra performance liquid chromatography (UPLC) coupled with photo diode array detector. The dried (65 °C, 72 h) and powdered sample (5 g) was extracted with ethanol (15%, 100 ml) for 30 min at 50 °C and concentrate. The constituents were separated using an isocratic mobile phase consisting acetonitrile (16%) in water for 10 min on a ODS column. The contents of panaxfuraynes A and B in the roots of Panax quinquefolium, Panax japonicum, Panax notoginseng and P. ginseng were found to less than 3 and 2 ng/g approximately, respectively. The constituents were not detected from P. japonicum.     

Spherical approximation for multiple cameras in motion estimation: Its applicability and advantages

Estimating motions of a multi-camera system which may not have overlapping fields of view is generally complex and computationally expensive because of the non-zero offset between each camera’s center. It is conceivable that if we can assume that multiple cameras share a single optical center, and thus can be modeled as a spherical imaging system, motion estimation and calibration of this system would become simpler and more efficient.     

A systematic framework for evaluating design concepts of a new product

This study aims to suggest a systematic framework to evaluate design concepts for a new product at the concept‐development phase. It focuses especially on evaluating design concepts based on user requirements and implicit tasks, defining trends in technology alternatives, and relating users' perceived value to product functionality. The potential user needs and functional requirements were identified through scenario‐based analysis and hierarchical task analysis. Technology alternatives were also investigated to support users in performing the required tasks effectively and efficiently. For a quantifiable evaluation measure, customer‐perceived value (CPV) attributes were used to evaluate the benefits and costs of the current design concept as compared to perceived alternatives. A case study was conducted to evaluate the design concepts of a new computer‐supported cooperative work (CSCW)‐based system with a tangible user interface, which was designed to support group decision‐making activities, such as business meetings. At the concept‐development phase, engineering specifications are not determined, and cost cannot be precisely estimated. Thus, while we dealt with design‐concept evaluation, we had no choice but to exclude cost attributes, such as monetary expenditure. It is still expected that our framework would be effective in incorporating user‐centered design perspectives early in the process of new product development. © 2010 Wiley Periodicals, Inc.