Hideki Kuramitz

Toyama University, Тояма, Toyama, Japan

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Publications (87)191.56 Total impact


  • No preview · Conference Paper · Nov 2015

  • No preview · Conference Paper · Oct 2015

  • No preview · Conference Paper · Sep 2015
  • Hiroki Shinohara · Hideki Kuramitz · Kazuharu Sugawara
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    ABSTRACT: We designed a new electroactive peptide probe that has a molecular recognition function for the sensing of a protein. Ovalbumin (OVA) was the model protein, and when RNRCKGTDVQAW interacted with OVA, it conjugated with a tyrosine-rich peptide (Y4C). This peptide is electroactive, has a high degree of biocompatibility, and offers the possibility of gene expression. To measure the effect of a number of the tyrosine residues, voltammetric measurements were conducted using a series of tyrosine-rich peptides (YnC, n = 3-7) with sensitivities that ranged from 10(-9) to 10(-8) M. The electrode response of Y5C was the maximum value in the series. However, the peak current did not increase when the number of tyrosine residues was increased in a linear fashion. This may have been due to the micelles that are formed by a tyrosine-rich surfactant peptide. Thus, Y4C was suitable as an electroactive label for the construction of the peptide probe. The electrode response of Y4CRNRCKGTDVQAW obtained by a glassy carbon electrode was 100-fold that of tyrosine alone. The measurement of OVA via the peptide probe resulted in a detection on the order of 10(-12) M. In contrast, the sensitivity of OVA using RCKGTDVQAWY4C probe was at the 10(-11) M level, because the hydrophobic moiety gave it a molecular recognition function. The recoveries of the OVA using Y4CRNRCKGTDVQAW in a solution containing fetal bovine serum ranged between 98 and 101%. Consequently, the combination of a specific peptide and an electroactive element could be a powerful probe for the sensing of proteins.
    No preview · Article · Sep 2015 · Analytica chimica acta
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    ABSTRACT: In this paper, we introduce a simple and effective method to improve the transmission power respond of a polyelectrolyte (PE)-coated arc-induced long-period fiber grating (LPFG) sensor toward external perturbation. Experiments using single-pass and double-pass configurations were conducted to measure sucrose concentrations of between 0 and 80 wt%. The results showed that the transmission power sensitivity of the PE-coated LPFG sensor in the double-pass configuration was almost double compared to the single-pass configuration.
    Full-text · Article · Jul 2015 · Journal of Electromagnetic Waves and Applications
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    ABSTRACT: A simple and rapid pre-concentration technique was proposed for the simultaneous determination of eight trace heavy metals in water by energy-dispersive X-ray fluorescence (EDXRF) spectrometry. Yttrium was added as a carrier ion to a sample solution containing Cd, Cr, Cu, Fe, Mn, Ni, Pb and Zn. The metals were collected on a membrane filter as precipitates or co-precipitates with 1-(2-pyridylazo)-2-naphthol at pH 10. The metals on the filter were determined by EDXRF spectrometry. Yttrium improved the collection efficiency of Cr(III) drastically and also expanded the pH ranges for quantitative recoveries of the metals. Only fifteen min was required to prepare the membrane filter retaining the metals. Linear calibrations were obtained from μg L-1 to mg L-1 levels of the metals in 50 mL sample solution. The limits of detection were as follows: Cd, 1 μg L-1 ; Cr, 0.3 μg L-1; Cu, 1 μg L-1; Fe, 1 μg L-1; Mn, 0.3 μg L-1; Ni, 2 μg L-1; Pb, 2 μg L-1; Zn, 2 μg L-1. The sensitivities were enough for monitoring drinking water. The proposed method was applied to river water and underground waters. The analytical results were agreed with those obtained by GF-AAS for the detected metals. The recoveries of the spiked metals in the waters were quantitative. This method was advanced to the separation and determination of Cr(III) and Cr (VI). The proposed system of pre-concentration and EDXRF spectrometry has high potential for routine monitoring of trace heavy metals because of its simplicity and rapidity besides cost-effectiveness.
    No preview · Article · Jul 2015 · Analytical methods
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    ABSTRACT: A study based on the physicochemical parameters and dissolved metals levels from three main rivers around Dhaka City, Bangladesh, was conducted in order to determine the present pollution status and their alteration trends with the seasonal change of discharge amount. The water samples were collected from the rivers Buriganga, Turag, and Shitalakkhya during both dry and monsoon seasons. Physicochemical analyses revealed that most of the water quality parameters exceeded the recommended levels set by the Department of Environment (DoE), Bangladesh, during both the dry and monsoon OPEN ACCESS Environments2015, 2 281 seasons. A very strong positive correlation was found between biochemical oxygen demand (BOD) and chemical oxygen demand (COD) in all sampling points. Both BOD and COD values had a strong negative correlation with dissolved oxygen (DO) in the Shitalakkhya River. Most of the dissolved metals concentrations in the water samples were similar. However, the concentrations of different physicochemical properties varied with the seasons. The dry season had significantly higher contamination loads, which were decreased during the monsoon season. Anthropogenic activities, as well as the variation in river water flow during different seasons were the main reasons for this high degree of water pollution.
    Full-text · Article · Jun 2015 · Environments
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    ABSTRACT: Coagulation experiments were performed to find out the optimum coagulant and alkaline chemical for the removal of humic acid (HA) from environmental water. This research clearly indicates the effectiveness of coagulation method using polyaluminum chloride (PAC) with calcium carbonate as neutralizer and coagulant aid to remove HA. The removal of HA was evaluated from absorbance at 260 nm and concentration of dissolved organic carbon (DOC). The highest removal ratio was found to be 96.6% for the absorbance of HA and 91.6% for DOC concentration when 30 mg/L of PAC with calcium carbonate (CaCO3) was used as an alkaline reagent. In this method, the sludge volume (SV) was reduced about half compared with the PAC method using NaOH as neutralizer. Ca2+ which is derived from CaCO3 makes HA colloid size bigger and easier to form flocks because of the compression in the electrical double layer (EDL) between HA colloids. The adsorption of HA onto porous CaCO3 particles also plays an important role. The experiments conducted with sample water collected from Sebangau River, Indonesia consists of 33.4 mg/L of DOC and was found to have a removal efficiency of 86.5%, whereby the final concentration of DOC was 4.5 mg/L. These results suggested that CaCO3 requires a lesser amount of coagulants and also shortens the settling time. This proposed technique provides a more effective and conventional removal method for HA by coagulation-precipitation processes.
    Full-text · Article · Jun 2015 · Journal of Environmental Chemical Engineering
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    ABSTRACT: A rapid and simple method for the determination of anionic surfactants based on an evanescent wave fiber optic was developed using ethyl violet. The sensor was prepared by removing the middle of the multimode fiber cladding. The optical signal from ethyl violet decreased with an increase in the sodium dodecyl sulfate concentration. The calibration curve was linear from 4 to 15 milligrams per liter with a limit of detection of 3.3 milligrams per liter. This simple fiber optic sensor requires a low volume of sample and does not employ extraction with organic solvents compared with conventional methods.
    No preview · Article · May 2015 · Analytical Letters
  • Kazuharu Sugawara · Toshihiko Kadoya · Hideki Kuramitz
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    ABSTRACT: Daunomycin penetrates the membrane of a U937 cell, which is a human histiocyte-related lymphoma cell. Several arginine-rich peptides have also exhibited a high degree of permeability with these cells. Therefore, we attempted to improve the membrane permeability of daunomycin by coupling it with an arginine-rich peptide. The cell membrane permeability of daunomycin was monitored using voltammetry, because daunomycin is an electroactive compound. First, daunomycin was combined with N-(6-maleimidocaproyloxy)sulfosuccinimide. Second, the cross-linking agent with daunomycin was bound to the cysteine residue of RRRRRRRRGC (peptide-1). The two-step synthesis suppressed the formation of by-products that might have conjugated with the amino groups of peptide-1. After the quinone moieties of daunomycin were reduced using an electrode, an oxidation peak appeared due to the moieties. The peak current of daunomycin with U937 cells had decreased. For the mixture of the daunomycin/peptide-1 probe and cells, the electrode response was smaller than that of daunomycin with the cells. Thus, the membrane penetration of the daunomycin/peptide-1 probe was improved compared with the use of only daunomycin. In addition, the membrane penetration of the probe was measured using fluorescence spectroscopy. The sensitivity of the electrochemical procedure was 100-fold that was obtained by fluorescence spectrometry. Copyright © 2015 Elsevier B.V. All rights reserved.
    No preview · Article · May 2015 · Bioelectrochemistry
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    Kazuto Sazawa · Hideki Kuramitz
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    ABSTRACT: Soil enzymes play essential roles in catalyzing reactions necessary for nutrient cycling in the biosphere. They are also sensitive indicators of ecosystem stress, therefore their evaluation is very important in assessing soil health and quality. The standard soil enzyme assay method based on spectroscopic detection is a complicated operation that requires the removal of soil particles. The purpose of this study was to develop a new soil enzyme assay based on hydrodynamic electrochemical detection using a rotating disk electrode in a microliter droplet. The activities of enzymes were determined by measuring the electrochemical oxidation of p-aminophenol (PAP), following the enzymatic conversion of substrate-conjugated PAP. The calibration curves of β-galactosidase (β-gal), β-glucosidase (β-glu) and acid phosphatase (AcP) showed good linear correlation after being spiked in soils using chronoamperometry. We also performed electrochemical detection using real soils. Hydrodynamic chronoamperometry can be used to assess the AcP in soils, with a detection time of only 90 s. Linear sweep voltammetry was used to measure the amount of PAP released from β-gal and β-glu by enzymatic reaction after 60 min. For the assessment of soil enzymes, the results of hydrodynamic voltammetry assay compared favorably to those using a standard assay procedure, but this new procedure is more user-friendly, rapid and simple.
    Preview · Article · Mar 2015 · Sensors
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    ABSTRACT: This study proposes an optical fiber sensor for calcium carbonate (CaCO3) scale formation in water. The sensor is easily fabricated by removing the cladding of a multimode fiber to expose the core towards the surrounding medium in order to detect refractive index change. A variation of the transmittance response from the high refractive index of CaCO3 which precipitated on the fiber core surface was observed. The proposed setup can be used to analyze the transmittance response over wide range of wavelength using white light as a source and also a spectroscopy detector. The curve of the transmittance percentage over time showed that a fiber core with 200 μm has higher sensitivity as compared to a fiber core with 400 μm. The findings from this study showed that the sensor detection region at near infrared (NIR) wavelengths showed better sensitivity than visible light (VIS) wavelengths. Field tests were conducted using natural geothermal water at Matsushiro, Japan in order to verify the performance of the proposed sensor. The optical response was successfully evaluated and the analytical results confirmed the capability of monitoring scale formation in a geothermal water environment.
    Full-text · Article · Mar 2015 · Analytical Sciences
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    ABSTRACT: A sensitive visual colorimetry was proposed for the on-site determination of arsenic in drinking water supplied from ground water. The method was based on an advanced molybdenum blue (MB) colorimetry combined with enrichment technique using membrane filter. A portable device equipped with two attachments of a CaCO3-cartridge was used to eliminate interference from phosphate and a tiny membrane holder to retain the MB was proposed for on-site analysis. Ten mL of sample solution containing 0.1-0.4 μg arsenic was passed through the CaCO3-cartridge. The arsenic in the sample solution was converted into MB and collected on a membrane filter as an ion-associate with a cationic surfactant. The arsenic was determined visually from the color intensity of the filter using color chart made from standard solution. The sensitivity is sufficient to detect the concentration of 10 μg L-1 adopted by the WHO standard. The speciation analysis for As(III) and As(V) was also successfully performed. The proposed method was applied to several ground water samples, and the analytical results were well comparable with those obtained by HG-AAS.
    No preview · Article · Feb 2015 · Analytical methods
  • Kazuharu Sugawara · Toshihiko Kadoya · Hideki Kuramitz
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    ABSTRACT: In this study, a peptide-1 (RNRCKGTDVQAW) constructing lysozyme was conjugated with an electroactive daunomycin in order to voltammetrically detect ovalbumin (OVA). Hetero-bifunctional cross-linking agents with four kinds of ethylene chains in differing lengths were used to bind the peptide-1 and daunomycin. After a cross-linking agent had reacted with an amino group of daunomycin, the compound was introduced into the peptide to the cysteine residue in the peptide using a pendant arm. The OVA was sensed via a change in the electrode response of the daunomycin moiety, based on the binding between the peptide and the OVA. The adsorption of the peptide probe on the electrode increased with increases in the ethylene chain. The binding constants between the peptide probes and the OVA, however, did not depend on the length of the chain. This was because the ethylene chain influenced the binding. When the peptide and the daunomycin were bound using N-(6-maleimidocaproyloxy) sulfosuccinimide, the electrode response of the peptide probe was the most sensitive from among the four cross-linking agents. The calibration curve of the OVA using the peptide probe was linear and ranged from 1.5 × 10−11 to 3.0 × 10−10 M. Furthermore, this method could be applied to the electrochemical sensing of the OVA in egg whites and in fetal bovine serum.
    No preview · Article · Feb 2015 · Analytica Chimica Acta
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    ABSTRACT: Herein, we present a novel spectroelectrochemical fiber optic sensor that combines electrochemistry, spectroscopy, and electrostatic adsorption in three modes of selectivity. The proposed sensor is simple and consists of a gold mesh cover on a multimode fiber optic that uses attenuated total reflection (ATR) as the optical detection mode. The sensing is based on changes in the attenuation of the light that passes through the fiber optic core accompanying the electrochemical oxidation-reduction of an analyte at the electrode. Methylene blue and ferrocyanide were used as model analytes to evaluate the performance of the proposed sensor. The optical transmission changes generated by electrochemical manipulation showed a good linear relationship with the concentration and the limits of detection (3σ) for methylene blue and ferrocyanide at 2.0×10-7 M and 1.6×10-3 M, respectively. The sensor responses were successfully enhanced with an additional level of selectivity via an electrostatically adsorpted, self-assembled monolayer (SAM), which consisted of a silane coupling layer, a poly anion, and a poly cation. The improvement observed in the sensitivity of a SAM-modified fiber optic sensor was rather encouraging. The optimized sensor had detection limits (3σ) for 8.3×10-9 M of methylene blue and 7.1×10-4 M of ferrocyanide. The developed sensor was successfully applied to the detection of ferrocyanide in stimulated nuclear waste.
    No preview · Article · Jan 2015 · Analytical Chemistry
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    Mey C. Loh · Faidz A. Rahman · Hideki Kuramitz · Yun T. Yong
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    ABSTRACT: The sensitivity of the arc-induced long period fiber grating (LPFG) sensor was improved utilizing the double-pass configuration. The sensitivity in terms of transmission attenuation of the resonance wavelength for the double-pass LPFG configuration was better compared to the single-pass configuration when it was used to monitor the avidin–biotin interaction over a period of 60 min. © 2014 Wiley Periodicals, Inc. Microwave Opt Technol Lett 56:2766–2769, 2014
    Full-text · Article · Dec 2014 · Microwave and Optical Technology Letters
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    Full-text · Conference Paper · Sep 2014
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    ABSTRACT: Tetrabromobisphenol A (TBBPA), a type of brominated flame retardant that shows endocrine disruption effects, has been identified in leachates from landfills. Iron(III)-porphyrins that mimic the active site of peroxidases have been shown to be effective in oxidizing halogenated phenols, such as TBBPA. In the present study, TBBPA was subjected to oxidation with potassium monopersulfate (KHSO5) using an iron(III)-phthalocyanine-tetrasulfonic acid (FePcTS), structural analogue of iron(III)-porphyrin, in the presence of humic acid (HA), a major component in landfill leachates. When TBBPA was oxidized using the above system, the levels of degradation and debromination increased with increasing pH in the presence of HA. Because of landfill leachates are weakly alkaline (around pH 8), oxidation products derived from TBBPA were investigated at pH 8. Approximately 48% of the bromine in the degraded TBBPA was incorporated into HA, and hydroxy-tribromobisphenol A was determined to be the major brominated intermediate in the HA fraction. In the iron(III)-porphyrin catalytic systems, the brominated intermediate incorporated into HA is mainly TBBPA, and no hydroxy-substituted bromophenols are found. Thus, the catalytic power of FePcTS is higher than that of iron(III)-porphyrin catalysts.
    No preview · Article · Jul 2014 · Journal of Environmental Science and Health Part A Toxic/Hazardous Substances & Environmental Engineering
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    ABSTRACT: For this study, a new method was developed to electrochemically detect ovalbumin via its binding with the peptide-1(RNRCKGTDVQAW) in lysozymes. The peptide that exists at the C-terminal of a lysozyme was combined with ovalbumin. When an electroactive compound was introduced to the N-terminal side of the peptide through ethylene gycolbis(sulfosuccinimidyl succinate), the labeled peptide-1 served as a probe for the detection of ovalbumin. The electrode responses of labeled peptide-1 were measured after the labeled peptide-1 and ovalbumin were incubated in a 0.1M phosphate buffer (pH 5.6). As a result, the electrode response decreased as the concentration of ovalbumin increased. The detection limit of ovalbumin was 2.3×10(-11)M as estimated at 3-fold the standard deviation (3σ) (n=5). Because the steric structure of the peptide and some of the amino acid residues were related to the binding, we prepared a peptide-2, to which the N- and C-terminals of peptide-1 were alternated. The decrease in the response for the labeled peptide-2 was less than that for the labeled peptide-1. In addition, the peak current of a peptide-3, for which the D of peptide-1 was replaced with S, was hardly changed with or without ovalbumin. Therefore, it was clear that the binding was influenced by the steric factors and by the sequence of the peptide. However, a peptide-1 with bis(sulfosuccinimidyl) suberate was designed to investigate the hydrophobic influences on the probe. The change in the peak current was smaller than that of peptide-1 with ethylene gycolbis(sulfosuccinimidyl succinate), which was due to the hydrophobic properties of the alkyl chain between the peptide and the ovalbumin. The proposed method could be applied to the determination of ovalbumin in egg whites. Consequently, the concept becomes an electrochemical sensing method for proteins based on the protein-peptide interaction.
    No preview · Article · Jun 2014 · Analytica Chimica Acta
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    ABSTRACT: When peat forest fires happen, it leads to burn soil and also humic acids as a dominant organic matter contained in peat soil as well as the forest. The structure and properties of humic acids vary depending on their origin and environment, therefore the transformation of humic acid is also diverse. The impacts of the peat fires on peat soil from Central Kalimantan, Indonesia were investigated through the characterization of humic acids, extracted from soil in burnt and unburnt sites. The characterization of humic acids was performed by elemental composition, functional groups, molecular weight by HPSEC, pyrolysate compounds by pyrolysis-GC/MS, fluorescence spectrum by 3DEEM spectrofluorometer, and thermogravimetry. The elemental composition of each humic substance indicated that the value of H/C and O/C of humic acids from burnt sites were lower than that from unburnt sites. The molecular weight of humic acids from burnt sites was also lower than that from unburnt sites. Pyrolysate compounds of humic acids from unburnt sites differed from those of humic acids from burnt soil. The heating experiment showed that burning process caused the significant change in the properties of humic acids such as increasing the aromaticity and decreasing the molecular weight.
    No preview · Article · May 2014 · Environmental Science and Pollution Research

Publication Stats

933 Citations
191.56 Total Impact Points

Institutions

  • 2005-2015
    • Toyama University
      Тояма, Toyama, Japan
  • 2006-2014
    • University of Toyama
      • Department of Environmental Biology and Chemistry
      Тояма, Toyama, Japan
  • 2004-2009
    • University of Cincinnati
      • Department of Chemistry
      Cincinnati, Ohio, United States
  • 1999-2005
    • Hokkaido University
      • Graduate School of Environmental Science
      Sapporo, Hokkaidō, Japan
  • 2002
    • Gunma University
      • Faculty of Education
      Maebashi, Gunma Prefecture, Japan