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PubMed | Kobe Institute of Health, Meijo University and Aichi Science and Technology Foundation
Type: | Journal: Journal of microbiological methods | Year: 2015

O157, O26, and O111 are the most important O serogroups of enterohemorrhagic Escherichia coli worldwide. Recently we reported a strategy for discriminating these serotypes from the others using matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) based on the S10-spc-alpha operon gene-encoded ribosomal protein mass spectrum (S10-GERMS) method. To realize the fully automated identification of microorganisms at species- or serotype-level with the concept of S10-GERMS method, novel software named Strain Solution for MALDI-TOF MS was developed. In this study, the Strain Solution was evaluated with a total of 45 E. coli isolates including O26, O91, O103, O111, O115, O121, O128, O145, O157, O159, and untyped serotypes. The Strain Solution could accurately discriminate 92% (11/12) of O157 strains, 100% (13/13) of O26 and O111 strains from the others with three biomarkers in an automated manner. In addition, this software could identify 2 different E. coli strains (K-12 as a non-O157 representative and O157) in mixed samples. The results suggest that Strain Solution will be useful for species- or serotype-level classification of microorganisms in the fields of food safety and diagnostics.

PubMed | Tohoku University, Nagoya City University, Aichi Medical University, Nagoya University and Aichi Science and Technology Foundation
Type: Journal Article | Journal: Journal of exposure science & environmental epidemiology | Year: 2014

The aim of this study was to develop a method for quantitative measurement of urinary metabolites of pyrethroid (PYR) insecticides, trans-chrysanthemumdicarboxylic acid (CDCA) and 3-phenoxybenzoic acid (3-PBA), extracted from disposable diapers. This study was approved by the university ethics committees, and informed consent was obtained from all the parents for their children and from adult volunteers. After extraction of PYR metabolites in the absorber of diapers with 5ml acetone, the metabolites in the eluents were extracted with tert-butyl methyl ether, derivatized with 1,1,1,3,3,3-hexafluoroisopropanol and analyzed by gas chromatography-mass spectrometry. The limits of quantitation (LOQs) were 0.55g/l for CDCA and 0.09g/l for 3-PBA in 2ml urine extracted from diapers. Within-series and between-day precisions were <14% (CV%) over the concentration range of metabolites from 0.4 to 20.4g/l urine. When concentrations of each metabolite were measured with the developed method after pouring 2ml urine, which was obtained from adults both in a general population and pest control operators, on diapers, good correlations were shown between the measured results and the concentrations measured directly for the respective urine with the conventional method (Spearmans rank correlation coefficient 0.889 for CDCA and 0.989 for 3-PBA; n=27-28). The developed method would be applicable to epidemiological studies.

Ojima-Kato T.,Aichi Science and Technology Foundation | Ojima-Kato T.,Meijo University | Yamamoto N.,Meijo University | Takahashi H.,Tokyo University of Marine Science and Technology | And 2 more authors.
PLoS ONE | Year: 2016

The genetic lineages of Listeria monocytogenes and other species of the genus Listeria are correlated with pathogenesis in humans. Although matrix-assisted laser desorption ionization-time of flight mass spectrometry (MALDI-TOF MS) has become a prevailing tool for rapid and reliable microbial identification, the precise discrimination of Listeria species and lineages remains a crucial issue in clinical settings and for food safety. In this study, we constructed an accurate and reliable MS database to discriminate the lineages of L. monocytogenes and the species of Listeria (L. monocytogenes, L. innocua, L. welshimeri, L. seeligeri, L. ivanovii, L. grayi, and L. rocourtiae) based on the S10-spc-alpha operon gene encoded ribosomal protein mass spectrum (S10-GERMS) proteotyping method, which relies on both genetic information (genomics) and observed MS peaks in MALDI-TOF MS (proteomics). The specific set of eight biomarkers (ribosomal proteins L24, L6, L18, L15, S11, S9, L31 type B, and S16) yielded characteristic MS patterns for the lineages of L. monocytogenes and the different species of Listeria, and led to the construction of a MS database that was successful in discriminating between these organisms in MALDI-TOF MS fingerprinting analysis followed by advanced proteotyping software Strain Solution analysis. We also confirmed the constructed database on the proteotyping software Strain Solution by using 23 Listeria strains collected from natural sources. © 2016 Ojima-Kato et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Mukai I.,Corpolation Society of ATS Method | Shu S.,Aichi Science and Technology Foundation
Japan Journal of Food Engineering | Year: 2015

Recently, remarkable progress in the fields of IT, biotechnology, space-technology has been achieved. However, it seems that only low development has been achieved in the retort sterilization technology, especially in the methods to estimate temperature of central part of foods exactly. An improved estimation method named ATS method (Ambient Temperature Slide method) was developed to solve some theoretical and practical problems in the sterilization technology in 2006. Both accuracy and convenience of the ATS method have been inspected enough so far by many experimental data, however, the ATS method have been doubted regarding propriety of assumption that the deviation rate (β) of temperature of central part of packed foods from spacemean temperature is equal to one (1). This theoretical problem could be solved by using a similarity relation between the temperature history curves of the space-mean and the central part of the packed food. In addition, it was found that a heat-transfer coefficient (h) was a very small value compared to conventional expectation by using one-dimensional finite-difference method in retort sterilization. This new finding should be investigated by further experiments. © 2015, Japan Society for Food Engineering. All rights reserved.

Murakami Y.,Japan National Institute of Advanced Industrial Science and Technology | Miwa K.,Aichi Science and Technology Foundation | Omura N.,Japan National Institute of Advanced Industrial Science and Technology | Tada S.,Japan National Institute of Advanced Industrial Science and Technology
Materials Transactions | Year: 2012

Semisolid injection molding is expected to be increasingly utilized as a forming process applicable to highly flammable magnesium alloys, since it can be carried out at temperatures lower than those of die casting. In this study, we investigated the effects of molding conditions on the tensile strength and internal casting defects of AZ91D magnesium alloy. Semisolid injection molding was conducted at injection speeds of 220, 300 and 400 mm·s 11 and fraction solids of 0.0, 0.3, 0.4 and 0.5. Whereas the volume fraction of casting defects decreased together with the decrease of injection speed, the mechanical strength reached a maximum at an injection speed of 300 mm·s 11. The investigation results show that in the solidification microstructure, i-Mg and c-Mg 17Al 12 phases, which were liquid during injection, were refined at higher injection speeds, suggesting that the tensile strength increases together with the injection speed if there are no casting defects. This trend might be due to the increased heat transfer coefficient between the mold and the slurry from the higher flow rate. On the other hand, the volume fraction of casting defects increased together with injection speed, and as a result the tensile strength deteriorated. When the injection speed was increased, the effects of decreased strength due to the increase in the volume fraction of casting defects counterbalanced the effects of increased strength due to the refinement of i-Mg + c-Mg 17Al 12 mixed phase. For this reason, the mechanical strength is considered to reach a maximum at an injection speed of 300 mm·s 11. Thus, we demonstrated that the tensile strength of semisolid products is affected not only by the volume fraction of casting defects, but also by the microstructure of the residual mixed phase precipitated, which is refined by increasing the injection speed.

Murakami Y.,Sustainable Development Technology | Miwa K.,Aichi Science and Technology Foundation | Kanetake N.,Nagoya University | Tada S.,Sustainable Development Technology
Magnesium Technology | Year: 2013

Semi-solid process is useful for magnesium alloys because processing temperatures lower than conventional casting processes result in decreased combustibility. Additionally it can decrease casting defects by the increased viscosity and decreased solidification shrinkage. In this study, casting defects of semi-solid injected AZ91D specimens were observed by X-ray CT tomography and tensile test was carried out. Thus, relations between casting defects and fracture starting point were investigated. As a result, the specimens were not always fractured at the site of the largest defect; meanwhile the defects situated near the surface or perpendicularly elongated to the tension axis exerted a potent influence on fracture.

Suzuki T.,Aichi Science and Technology Foundation | Hira H.,Daido University
International SAMPE Technical Conference | Year: 2014

Physical properties of epoxy matrix resins and carbon fiber reinforced polymer composites (CFRPs) prepared by vacuum-assisted resin transfer molding (VaRTM) technique were investigated. The epoxy matrix resins were composed of bisphenol-F epoxy, carboxylic anhydride hardener, curing accelerator, and reactive diluters. Glass transition and thermal degradation temperatures of the cured epoxy matrix resins were decreased by the addition of the reactive diluters, indicating decreased thermal stability. Rotational viscosities of uncured epoxy matrix resins were successfully reduced by the addition of the reactive diluters, which was essentially advantageous for resin infusion to carbon fiber cloth during the VaRTM process. However, flexural strength of the CFRP prepared by the VaRTM process was decreased by the addition of monoglycidyl reactive diluter as similar to the result of corresponding epoxy matrix resin, suggesting the inhibition of robust intermolecular cross-linking by the introduction of monoglycidyl group. Copyright 2014. Used by the Society of the Advancement of Material and Process Engineering with permission.

Murakami Y.,Japan National Institute of Advanced Industrial Science and Technology | Miwa K.,Aichi Science and Technology Foundation | Kito M.,Aisan Industry Co. | Honda T.,Aisan Industry Co. | And 2 more authors.
Materials Transactions | Year: 2013

The semi-solid process is viewed as a promising manufacturing method for producing nearly net-shaped metal products with low porosity and shrinkage. However, the semi-solid slurry is inferior to liquid state in terms of fluidity; thus, the semi-solid process exhibits low formability. Therefore, improving the fluidity of the semi-solid slurry is an important issue. To address the issue, we attempted to improve the fluidity by applying shear stress on the slurry at the gate of the mold. In this study, the effect of shear rate on the fluidity of the semi-solid slurry of the AC4CH aluminum alloy was investigated. The shear rate at the gate was controlled by changing the thickness of the gate to 1.0, 2.2, 3.1 and 4.0 mm. The fluidity was evaluated by injecting through a narrow gate into a spiral cavity in terms of the length that has flowed into the cavity. The microstructures were observed by optical microscopy. The roundness and diameter of the solid particles in the specimens were measured by image analysis. According to the results, the fluidity increased with increasing gate velocity or increasing shear rate at identical injection velocities. However, both the mean roundness and diameter of the solid particles in the specimen decreased with increase in the shear rate obtained by decreasing the gate thickness. Therefore, the slurry composed of fine spherical solid particles could be obtained with a high shear rate. Additionally, both the mean particle roundness and diameter correlated with fluidity. These results suggested that the fluidity of the slurry improved with increase in the gate velocity and the shear rate because the viscosity of slurry decreased. As mentioned previously, the fluidity of semi-solid slurry could be improved by controlling the gate velocity and shear rate. It is expected that this method can enable the production of semi-solid forming products with complex configurations. © 2013 The Japan Institute of Light Metals.

Fuchi S.,Aoyama Gakuin University | Shimizu Y.,Aoyama Gakuin University | Watanabe K.,Aoyama Gakuin University | Uemura H.,Aichi Science and Technology Foundation | Takeda Y.,Aichi Science and Technology Foundation
Applied Physics Express | Year: 2014

We have synthesized 0.3Sm2O3-0.12Pr2O 3-10Bi2O3-45Sb2O3- 45B2O3 glass as an ultrawide-band near-infrared phosphor for LED-based light sources. We have achieved an ultrawide-band luminescence from 760 to 1100nm with an output power of over 1mW by combining a blue LED with Sm3+,Pr3+-codoped borate glass in one package. Absorption bands corresponding to C-H and O-H stretchings in aqueous solutions of glucose have been observed using this light source and a multichannel spectrometer. These results indicate that the Sm3+,Pr3+-codoped borate glass combined with the blue LED is a useful novel light source for absorption spectrometry. © 2014 The Japan Society of Applied Physics.

PubMed | Japan Food Research Laboratories, Meijo University and Aichi Science and Technology Foundation
Type: Journal Article | Journal: PloS one | Year: 2014

Enterohemorrhagic Escherichia coli (EHEC), causes a potentially life-threatening infection in humans worldwide. Serovar O157:H7, and to a lesser extent serovars O26 and O111, are the most commonly reported EHEC serovars responsible for a large number of outbreaks. We have established a rapid discrimination method for E. coli serovars O157, O26 and O111 from other E. coli serovars, based on the pattern matching of mass spectrometry (MS) differences and the presence/absence of biomarker proteins detected in matrix-assisted laser desorption/ionization time-of-flight MS (MALDI-TOF MS). Three biomarkers, ribosomal proteins S15 and L25, and acid stress chaperone HdeB, with MS m/z peaks at 10138.6/10166.6, 10676.4/10694.4 and 9066.2, respectively, were identified as effective biomarkers for O157 discrimination. To distinguish serovars O26 and O111 from the others, DNA-binding protein H-NS, with an MS peak at m/z 15409.4/15425.4 was identified. Sequence analysis of the O157 biomarkers revealed that amino acid changes: Q80R in S15, M50I in L25 and one mutation within the start codon ATG to ATA in the encoded HdeB protein, contributed to the specific peak pattern in O157. We demonstrated semi-automated pattern matching using these biomarkers and successfully discriminated total 57 O157 strains, 20 O26 strains and 6 O111 strains with 100% reliability by conventional MALDI-TOF MS analysis, regardless of the sample conditions. Our simple strategy, based on the S10-spc-alpha operon gene-encoded ribosomal protein mass spectrum (S10-GERMS) method, therefore allows for the rapid and reliable detection of this pathogen and may prove to be an invaluable tool both clinically and in the food industry.

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