We developed a microscope by a combination of synchrotron radiation X-ray fluorescence (SR-XRF) microscope and scanning electron microscope (SEM) with an energy dispersive X-ray spectrometer (EDX). ...SR-XRF is appropriate to detect trace and micro amount of elements and sensitive to heavy elements in an analyte but it cannot observe the real time image. SEM-EDX can observe the secondary electron image of a single particle in real time and is appropriate to detect lighter elements. This combination microscope can ensure the identification of the XRF spectrum to the SEM image without transferring the sample. For aerosol analysis, it is important to analyze each particle. The present method makes feasible to analyze not only the average elemental composition as the total particles but also elemental composition of each particle, which is dependent on the particle shape and size. The microscope was applied to an individual aerosol particle study. The X-ray spectra were different among the particles, but also different between SR-XRF and SEM-EDX for the same particle, due to the difference in fluorescence yields between X-ray excitation and electron excitation.
We developed a reliability index named SRED (Spot Reliability Evaluation Score for DNA microarrays) that represents the probability that the calibrated gene expression level from a DNA microarray ...would be less than a factor of 2 different from that of quantitative real-time polymerase chain reaction assays whose dynamic quantification range is treated statistically to be similar to that of the DNA microarray. To define the SRED score, two parameters, the reproducibility of measurement value and the relative expression value were selected from nine candidate parameters. The SRED score supplies the probability that the expression level in each spot of a microarray is less than a certain-fold different compared to other expression profiling data, such as QRT-PCR. This score was applied to ∼1,500,000 points of the expression profile in the RIKEN Expression Array Database.
We pursue research and development on the detection of the weak magnetic field generated by the neural propagation along the spinal cord and the investigation of non-invasive diagnosis of spinal cord ...function based on the analysis of the detected magnetic signals. So far, we have reported the developed prototype of the SQUID spinal cord evoked magnetic field (SCEF) measurement system applicable to patients with spinal cord disorder in actual hospitals. We have also reported the development of the visualization of the current distribution along the spinal cord by magnetic source analysis. In this paper, the improvement of the dynamic range by the newly designed multiple feedback FLL (flux locked loop) and the noise reduction using reference magnetic flux sensors are described. These features enabled to prevent saturation of the SQUID electronics and to detect separately not only the fast SCEF component reported previously but also the slow SCEF component simultaneously even in the presence of large low-frequency noise.
A new 10-stage low-pressure impactor of MAIS-10 has been developed to sample size-segregated aerosol particles for subsequent chemical analysis by ion or X-ray beam method such as PIXE or XRF and ...thermo-optical analysis for carbonaceous components. The impactor has reversible impaction plates with the diameters of the aerosol deposition areas smaller than 10 mm for all stages and can employ the collection substrates of two different thicknesses. The collection efficiency curves were experimentally determined for all stages and the 50% cut-off diameters ranging from 30 nm to 8 µm agreed well with the theoretical calculations at each stage. The particle wall losses were experimentally obtained using oleic acid particles labeled with uranine. The performance of MAIS-10 has been tested to collect urban aerosols simultaneously with a commercially available impactor for 24 hrs. The samples were subjected to TXRF, PIXE and thermal optical analysis. MAIS-10 samples showed the reasonable size distributions of typical elements and carbonaceous components, while the levels of the samples collected by the usual impactor in the analytical areas were below the detection limit of each analytical method and the size distributions were not able to be determined.
The RIKEN high-throughput 384-format sequencing pipeline (RISA system) including a 384-multicapillary sequencer (the so-called RISA sequencer) was developed for the RIKEN mouse encyclopedia project. ...The RISA system consists of colony picking, template preparation, sequencing reaction, and the sequencing process. A novel high-throughput 384-format capillary sequencer system (RISA sequencer system) was developed for the sequencing process. This system consists of a 384-multicapillary auto sequencer (RISA sequencer), a 384-multicapillary array assembler (CAS), and a 384-multicapillary casting device. The RISA sequencer can simultaneously analyze 384 independent sequencing products. The optical system is a scanning system chosen after careful comparison with an image detection system for the simultaneous detection of the 384-capillary array. This scanning system can be used with any fluorescent-labeled sequencing reaction (chain termination reaction), including transcriptional sequencing based on RNA polymerase, which was originally developed by us, and cycle sequencing based on thermostable DNA polymerase. For long-read sequencing, 380 out of 384 sequences (99.2%) were successfully analyzed and the average read length, with more than 99% accuracy, was 654.4 bp. A single RISA sequencer can analyze 216 kb with >99% accuracy in 2.7 h (90 kb/h). For short-read sequencing to cluster the 3' end and 5' end sequencing by reading 350 bp, 384 samples can be analyzed in 1.5 h. We have also developed a RISA inoculator, RISA filtrator and densitometer, RISA plasmid preparator which can handle throughput of 40,000 samples in 17.5 h, and a high-throughput RISA thermal cycler which has four 384-well sites. The combination of these technologies allowed us to construct the RISA system consisting of 16 RISA sequencers, which can process 50,000 DNA samples per day. One haploid genome shotgun sequence of a higher organism, such as human, mouse, rat, domestic animals, and plants, can be revealed by seven RISA systems within one month.
X-ray fluorescence spectra have a tail in their low-energy side of characteristic discrete lines. Though the origin of the tailing was believed to be a response of electron gas in the conduction band ...to the creation of a core hole, the author proposes a new interpretation; the radiative Auger effect is an additional origin of the tailing. Information contained in the shape of tailing is discussed.
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