Geo-referenced multimedia environmental fate model (G-CIEMS): model formulation and comparison to the generic model and monitoring approaches

A spatially resolved and geo-referenced dynamic multimedia environmental fate model, G-CIEMS (Grid-Catchment Integrated Environmental Modeling System) was developed on a geographical information system (GIS). The case study for Japan based on the air grid cells of 5 x 5 km resolution and catchments with an average area of 9.3 km2, which corresponds to about 40,000 air grid cells and 38,000 river segments/catchment polygons, were performed for dioxins, benzene, 1,3-butadiene, and di-(2-ethyhexyl)phthalate. The averaged concentration of the model and monitoring output were within a factor of 2-3 for all the media. Outputs from G-CIEMS and the generic model were essentially comparable when identical parameters were employed, whereas the G-CIEMS model gave explicit information of distribution of chemicals in the environment. Exposure-weighted averaged concentrations (EWAC) in air were calculated to estimate the exposure ofthe population, based on the results of generic, G-CIEMS, and monitoring approaches. The G-CIEMS approach showed significantly better agreement with the monitoring-derived EWAC than the generic model approach. Implication for the use of a geo-referenced modeling approach in the risk assessment scheme is discussed as a generic-spatial approach, which can be used to provide more accurate exposure estimation with distribution information, using generally available data sources for a wide range of chemicals.     

Nitrosomonas communis strain YNSRA, an ammonia-oxidizing bacterium, isolated from the reed rhizoplane in an aquaponics plant

An ammonia-oxidizing bacterium (strain YNSRA) was isolated from the rhizoplane of the reed (Phragmites communis) used in an aquaponics plant which is a wastewater treatment plant. Strain YNSRA was identified as Nitrosomonas communis by taxonomic studies. The hydroxylamine-cytochrome c reductase (HCR) of strain YNSRA was found to have a higher activity (25.60 u/mg) than that of Nitrosomonas europaea ATCC25978T (8.94 u/mg). Ribulose-1,5-bisphosphate carboxylase (RubisCO) activity was detected at very low levels in strain YNSRA, whereas strain ATCC25978T had definite activity.     

Identification of the luciferin-luciferase system and quantification of coelenterazine by mass spectrometry in the deep-sea luminous ostracod Conchoecia pseudodiscophora

The bioluminescence system of the ostracod Conchoecia pseudodiscophora, which is abundant in the Sea of Japan, has been characterized. The luminescence (lambda(max)=463 nm) is produced by a luciferin-luciferase reaction, and the luciferin has been identified as coelenterazine. Coelenterazine, coelenteramide, and coelenteramine from C. pseudodiscophora were quantified by LC-ESI-MS/MS analysis. The coelenterazine content was estimated to be approximately 230 pg per animal by using a calibration curve of synthetic coelenterazine. The reaction between homogenates of C. pseudodiscophora and synthetic coelenterazine showed luminescence activity; this suggests that a coelenterazine-type luciferase is present.     

Fabrication of diffraction grating for X-ray Talbot interferometer

Imaging technology using the phase data attracts attention from many researchers as the observation technique of a biomechanical material. We produced a diffraction grating for obtaining high-resolution phase data. We designed the new process flow and developed the fabrication technique composed of MEMS technology, X-ray lithography, and micro electroplating. The X-ray lithography process was performed using the NewSUBARU synchrotron radiation facility. The line and the aspect ratio of this grating were 4 μm and above 5 μm, respectively. We evaluated the diffraction grating in SPring-8.     

Large area and wide dimensions X-ray lithography using energy variable synchrotron radiation

We developed a new X-ray lithography system for the lithographite, galvanoformung and abformung (LIGA) process using synchrotron radiation at the New SUBARU facility of the University of Hyogo. The X-ray lithography system can utilize two different energy regions: one is a high-energy region: from 2 to 12 keV, and the other is a low-energy region from 1 to 2 keV. Each energy region can be selected in accordance with the size and shape of the desired microstructures. Large-area patterning across an A4-size area was successfully performed with a highly uniform pattern thickness. Furthermore, high-aspect-ratio patterning using a high-X-ray-energy region was also achieved using this X-ray lithography system.     

Planar microreactor for biochemical application made from silicon and polymer films

Recently the progress of life science has been increasing rapidly, and the importance of the microfluidics for DNA analysis systems has been widely recognized, especially in medical fields. The polymerase chain reaction (PCR) is an essential technique for DNA assay of various diseases and it has been a strong requirement to shorten the total of PCR cycles more and more. We developed the microreactor with a single cell for PCR using fabrication technologies of MEMS. The reactor body and cover were sealed using high thickness PDMS prototyping film without using adhesive in order to achieve repeat grabbing motion for direct sample injection, resumption and cleansing the reaction cell. Good reproducibility of the heat cycling was obtained. The heating rate and cooling rate during PCR was 6.8 and 2.7°C, respectively, which well corresponds to the design parameters. The homogenous temperature distribution of variance less than 2.0°C was obtained. It is demonstrated that amplification of the DNA was successfully achieved by using the microreactor.     

Structure of beta-amyloid fibrils and its relevance to their neurotoxicity: implications for the pathogenesis of Alzheimer's disease

Alzheimer's disease and cerebral amyloid angiopathy are characterized by the deposition of beta-amyloid fibrils consisting of 40- and 42-mer peptides (A beta 40 and A beta 42). Since the aggregation (fibrilization) of these peptides is closely related to the pathogenesis of these diseases, numerous structural analyses of A beta 40 and A beta 42 fibrils have been carried out. A beta 42 plays a more important role in the pathogenesis of these diseases since its aggregative ability and neurotoxicity are considerably greater than those of A beta 40. This review summarizes mainly our own recent findings from the structural analysis of A beta 42 fibrils and discusses its relevance to their neurotoxicity in vitro.     

Origins of material contrast in scanning ion microscope images

A Monte Carlo simulation of ion-induced kinetic electron emission (KE) was carried out to study the material contrast in scanning ion microscope (SIM) images, i.e. secondary electron (SE) yields decreasing with atomic number Z2 of the target, which is opposite to that for scanning electron microscope (SEM) images. The simulations show that SE yields decrease with increasing Z2 for the targets of Al (Z2 = 13), Cu (Z2 = 29) and Au (Z2 = 79) bombarded by 10 approximately 40 keV gallium (Ga) ions. Details of the SE yield according to the collision partners (i.e. Ga ion, recoiled target-atom and excited electron) clarify the origins of material (or Z2) contrast in the Ga-SIM images. Cause and effect on the material contrast are as follows: the heavier (or slower) collision partner transfers less energy to the excited electrons and leads to a poorer multiplication of other excited electrons in the cascade process. The simulation also predicts that the Ga-SIM images are more sensitive to the outermost target surface than the SEM images. material contrast, atomic number contrast, secondary electrons, secondary electron yield, scanning ion microscope, scanning electron microscope     

Fabrication of a distributed-feedback dye laser with a grating structure in its plastic waveguide

Two approaches of fabricating grating structures for waveguided plastic dye lasers are described and compared for lasing performance. Rhodamine6G-doped poly(methyl methacrylate) (PMMA) film on a PMMA substrate was used for the waveguide, and a distributed-feedback (DFB) laser operation with a single-propagation mode was demonstrated. The performances of both types of permanent grating structured DFB dye laser were better than those of a DFB dye laser on a plain waveguide with a dynamic grating formed by the interference of two pump beams. Wide tuning range is expected by use of a multistripe DFB laser with different grating pitches.