Nanopillar array chip integrated with on-line stacking for fast DNA separation with high sensitivity and high resolution

Recent developments of nanofabrication techniques have created a trend switching from randomly ordered polymeric matrices, such as gel, to highly ordered sieving nanostructures in the separation of biomolecules. These nanostructures have enormous potential for fast separation of biomolecules, while nanostructure-based separation techniques suffer from critical scaling problems; they are efficient in handling less than nanoliter amounts of sample fluids, but most biomolecule samples are available in a liquid volume that is over several microliter, leading to a reduction in sensitivity and resolution. In this study, we developed a nanopillar array chip integrated with an easy and rapid on-line stacking method and achieved fast DNA separation with high sensitivity and high resolution. The developed on-line stacking method is based on the balance of two forces driven by electric fields: electroosmotic flow (EOF) and electrophoresis. The EOF mobility from the microchannel to the nanopillar-channel is drastically decreased, while, on the other hand, electrophoresis has constant mobilities in the whole length of the channels. The on-line stacking was realized at the well-balanced position of the two forces, and the on-line stacking using the nanopillar array chip can also be achieved within 10 s by just applying electric voltages without any other special reagents and materials. After applying on-line stacking using the nanopillar array chip, the relative fluorescence intensity increased 1,000-fold, and the resolution was twice as good as that without on-line stacking.     

RADIOLYTIC DEGRADATION OF A CROWN ETHER FOR EXTRACT ABILITY OF STRONTIUM

ABSTRACT

Dicyclohexano- 18-crown-6 (DC18C6), dissolved in chloroform, 1-octanol, toluene or cyclohexane, was irradiated by ⁶⁰Co γ-rays. Radiolytic destruction of DC18C6, measured by gas chromatography, decreased in the order: chloroform > cyclohexane > 1-octanol > toluene. Distribution coefficients in the solvent extraction of strontium from nitric acid solution were measured. These distribution coefficients were minimally affected by γ-irradiation in toluene solution, but decreased with the absorbed dose in chloroform solution. It was suggested that the distribution coefficient for the liquid-liquid extraction system was influenced by radiolytic products. The effect of radiolytic products on the distribution coefficients was evaluated by considering DC18C6 remaining in the organic phase after irradiation. The distribution coefficient measured for the organic phase with radiolytic products was larger than that without radiolytic products. The radiolytic products were thus shown to contribute to the increase in the distribution coefficient.     

Framework for Performance-Based Design of Building Structures

Abstract:   This article proposes a new framework for performance-based design (PBD) of building structures. This framework was proposed under the 3-year Japanese Government Comprehensive Research and Development Project on "Development of a New Engineering Framework for Building Structures" launched in the fiscal year of 1995. The primary objective of the project is to create a system in which the performance of buildings is clearly stated, and consumers, that is, occupants, are well informed of how their buildings will perform and how much it will cost to maintain their performance. The framework emphasizes the establishment of target performance, the performance evaluation, and the performance statement as the main three elements. It also stresses that an institutional framework and support systems need to be provided to enable PBD to be practiced efficiently. The implementation of the proposed framework is also expected to promote engineering innovation, progress in building engineering, and globalization. The new framework will also bring other benefits, such as improved design techniques, greater design flexibility, and international harmonization. It is also important for building structural performance to become one of the most important indexes for consumers to define a building's value. The Japanese building code was changed to the performance-based code, based in the clear and comprehensive manner proposed in this article. In the United States, "Vision 2000" ( SEAOC, 1995 ) was published, then many research activities were conducted simultaneously.     

Development of systems reliability analysis code SECOM-2 for seismic PSA

An integrated code system SECOM-2, developed at the Japan Atomic Energy Research Institute (JAERI), has the following functions for systems reliability analysis in seismic probabilistic safety assessments (PSAs): (1) calculation of component failure probability, (2) extraction of minimal cut sets (MCSs) from a given fault tree (FT), (3) calculation of frequencies of accident sequences and core damage, (4) importance analysis with several measures with consideration of unique parameters of seismic PSAs, (5) sensitivity analysis, and (6) uncertainty analysis. This paper summarizes the special features of SECOM-2 to perform the analyses mentioned above. At JAERI, using an integrated FT which represents seismically induced core damage due to all initiating events as a system model to calculate core damage frequency of a nuclear power plant, SECOM-2 can calculate conditional point estimate probabilities of system failures, losses of safety functions, and core damage as a function of earthquake motions. The point estimate is computed by a method which gives an exact numerical solution using the Boolean arithmetic model method. As for consideration of correlation of component failure, which has been an important issue in seismic PSAs, a new technique based on direct FT quantification by a Monte Carlo simulation is being added to SECOM-2. Adding this technique, the core damage frequency can be calculated not only with the upper bound approximation based on MCSs but also with a near exact solution taking into account the correlation among all components. This paper also presents the preliminary results of a seismic PSA of a generic BWR plant in Japan performed at JAERI to demonstrate the functions of the SECOM-2 code.     

Double-level copper interconnections using selective copper CVD

Selective copper CVD technique involving hydrogen reduction of hexafluoro acetylacetonate copper has been used to fill vias for fabricating double-level copper interconnect structure. The surface morphology of selectively deposited copper on copper substrate of the via bottom depends strongly on via opening process. A two-step via opening process consisting of an reactive ion etching of the insulating interlayer and a wet removal of the interlayer metal results in smooth copper plug formation by CVD. Double-level copper interconnect structures have been fabricated using this technique and a via resistance as low as 100 mΩ has been obtained for a 1 μ diameter via.     

Influences of electroosmotic flows in nanopillar chips on DNA separation: Experimental results and numerical simulations

The various potential factors affecting the performance of nanopillar chips on DNA separation were investigated from the viewpoints of both numerical calculations and actual experiments. To yield higher performance and replace the conventional DNA separation techniques such as microchip electrophoresis, the phenomenon specific to the nanopillar chips should be deeply understood. In this paper, although various factors affecting the performance of the nanopillar chips are considered, we focused on the effect of electroosmotic flow, which is particularly noticeable in quartz-made nanopillar chips. High-resolution separation of DNA was realized when an electroosmotic flow was suppressed by simply using a higher concentration of buffer, but DNA separation failed in the presence of an electroosmotic flow. It was confirmed from the numerical simulations and the direct observations that the deformation of DNA band during the injection process was induced by electroosmotic flow and consequently led to a poor resolution.     

Why two kinds of color order systems are necessary?

Two kinds of color order systems—Type I (Munsell system, its representative) and Type II (Swedish Natural Colour System (NCS), its representative)—are widely used for systematic ordering of object colors. The reasons are clarified why two kinds of systems are necessary. The reasons are (1)the problem caused by the use of the present CIE photometric and colorimetric system and (2)the neglection of chromatic strength (CS) of each hue to perceived color attributes. In addition, a comparison is made between NCS and Nayatani Theoretical (NT) systems, which are in the same category of color order system–Type II. The importance of CS function is clarified in the comparison of the three color order systems studied. Special features of the three color order systems (Munsell, NCS, and NT) are described in detail. © 2005 Wiley Periodicals, Inc. Col Res Appl, 30, 295–303, 2005; Published online in Wiley InterScience (www.interscience.wiley.com). DOI 10.1002/col.20127