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Yoshinari Suzuki

Bio: Yoshinari Suzuki is an academic researcher from Chuo University. The author has contributed to research in topics: Inductively coupled plasma mass spectrometry & Selenium deficiency. The author has an hindex of 8, co-authored 13 publications receiving 220 citations.

Papers
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Journal ArticleDOI
TL;DR: Results show that atmospheric REE cycling is affected by the physico-chemical properties of APM, and Eu-selective dissolution from or adsorption onto the trapped particles of Eu might account for the negative anomaly.
Abstract: Concentrations of 14 rare earth elements (REEs) in six size classes of airborne particulate matter (APM) ( 11 μm) and in two different phases (suspended particulate and dissolved) in rainwater were determined by inductively coupled plasma mass spectrometry (ICP-MS). Positive Eu and Tb anomalies were observed in size-classified APM. These anomalies may be due to large emissions of Eu and Tb to the atmosphere resulting from the recent change in Japan from the use of cathode-ray tubes to plasma displays in television sets (Eu and Tb) and from the widespread use of magneto-optical disks (Tb). The light REEs were enriched in fine APM particles (diameter 2.1 μm), and a positive Tb anomaly was observed, suggesting that coarse particles easily become trapped in rain droplets. A negative Eu anomaly was observed in the dissolved phase in rainwater, but not in APM or in the suspended particulate phase in rainwater. Unlike other REEs, Eu can exist as both bivalent and trivalent ions in nature, and Eu-selective dissolution from or adsorption onto the trapped particles of Eu might account for the negative anomaly. These results show that atmospheric REE cycling is affected by the physico-chemical properties of APM.

52 citations

Journal ArticleDOI
TL;DR: The finding indicated that cGPx synthesis was suppressed under Se-deficient conditions and did not recover with selenite injection, and any excess amount of Se was excreted mainly as a selenosugar in urine.
Abstract: The selenoprotein, cellular glutathione peroxidase (cGPx), has an important role in protecting organisms from oxidative damage through reducing levels of harmful peroxides The liver and kidney in particular, have important roles in selenium (Se) metabolism and Se is excreted predominantly in urine and feces In order to characterize the dynamics of these pathways we have measured the time-dependent changes in the quantities of hepatic, renal, urinary, and fecal Se species in mice fed Se-adequate and Se-deficient diets after injection of (82)Se-enriched selenite Exogenous (82)Se was transformed to cGPx in both the liver and kidney within 1 h after injection and the synthesis of cGPx decreased 1 to 6 h and continued at a constant level from 6 to 72 h after injection The total amount of Se associated with cGPx in mice fed Se-deficient diets was found to be less than in mice fed Se-adequate diets This finding indicated that cGPx synthesis was suppressed under Se-deficient conditions and did not recover with selenite injection Excess Se was associated with selenosugar in liver and transported to the kidney within 1 h after injection, and then excreted in urine and feces within 6 h after injection Any excess amount of Se was excreted mainly as a selenosugar in urine

34 citations

Journal ArticleDOI
TL;DR: The analytical method established in this study was applied to the determination of REEs in APM collected in Tokyo, Japan and showed a high degree of the anthropogenic effect in fine APM with a diameter of <1.1 µm.
Abstract: The determination of rare earth elements (REEs) in airborne particulate matter (APM) was conducted, and the distribution pattern of atmospheric REEs was evaluated in this study. The APM was collected in the center of Tokyo, Japan, where serious air pollution is always of concern. A cellulose acetate membrane filter was used to collect the APM because Ba and REEs contamination is lower than that in a quartz glass fiber filter. The REEs measurement was conducted by ICP-MS after the digestion of the APM by a microwave acid digestion procedure. The standard reference material (SRM) of NIST 1648 urban particulate matter was used to validate the accuracy of the analytical method. The analytical results for SRM well agreed with those of the reference and reported values. Consequently, the analytical method established in this study was applied to the determination of REEs in APM collected in Tokyo, Japan. The obtained REEs distribution pattern in the APM showed a positive anomaly of Tb and Eu. The La/Sm ratio, which is considered to be as a good indicator of the anthropogenic effect, in size-classified APM showed a high degree of the anthropogenic effect in fine APM with a diameter of <1.1 μm. Emission sources of Tb, Eu and other REEs are discussed.

33 citations

Journal ArticleDOI
TL;DR: In this article, the authors used a differential mobility analyzer, an aerosol particle mass analyzer and a gas exchange device to continuously introduce airborne nanoparticles (ANPs) to an inductively coupled plasma mass spectrometer.
Abstract: We used a differential mobility analyzer, an aerosol particle mass analyzer, and a gas exchange device to continuously introduce airborne nanoparticles (ANPs) to an inductively coupled plasma mass spectrometer. Pb concentrations in single ANPs with a diameter of 90 nm and a mass of 0.458 fg (density is 1.20 g cm−3) were determined. The developed method enabled us to determine Pb in ANPs having a Pb content of more than 10%.

33 citations

Journal ArticleDOI
TL;DR: In this article, a new calibration system for real-time determination of trace elements in airborne particulates was developed, where external standard solutions were nebulized by an ultrasonic nebulizer (USN) coupled with a desolation sys-tem, and the resulting aerosol was introduced into the plasma.

23 citations


Cited by
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Journal ArticleDOI
TL;DR: This review summarizes the most recent findings on the biochemistry of active selenium species in humans, and addresses the latest evidence on the link betweenselenium intake, selenoproteins functionality and beneficial health effects.
Abstract: Despite its very low level in humans, selenium plays an important and unique role among the (semi)metal trace essential elements because it is the only one for which incorporation into proteins is genetically encoded, as the constitutive part of the 21st amino acid, selenocysteine. Twenty-five selenoproteins have been identified so far in the human proteome. The biological functions of some of them are still unknown, whereas for others there is evidence for a role in antioxidant defence, redox state regulation and a wide variety of specific metabolic pathways. In relation to these functions, the selenoproteins emerged in recent years as possible biomarkers of several diseases such as diabetes and several forms of cancer. Comprehension of the selenium biochemical pathways under normal physiological conditions is therefore an important requisite to elucidate its preventing/therapeutic effect for human diseases. This review summarizes the most recent findings on the biochemistry of active selenium species in humans, and addresses the latest evidence on the link between selenium intake, selenoproteins functionality and beneficial health effects. Primary emphasis is given to the interpretation of biochemical mechanisms rather than epidemiological/observational data. In this context, the review includes the following sections: (1) brief introduction; (2) general nutritional aspects of selenium; (3) global view of selenium metabolic routes; (4) detailed characterization of all human selenoproteins; (5) detailed discussion of the relation between selenoproteins and a variety of human diseases.

544 citations

Journal ArticleDOI
TL;DR: This review summarizes recent insights into properties of individual selenoproteins such as tissue distribution, subcellular localization, and regulation of expression as well as potential roles the different seleniproteins play in human health and disease.
Abstract: Selenium (Se) is a nutritional trace mineral essential for various aspects of human health that exerts its effects mainly through its incorporation into selenoproteins as the amino acid, selenocysteine. Twenty-five selenoprotein genes have been identified in humans and several selenoproteins are broadly classified as antioxidant enzymes. As progress is made on characterizing the individual members of this protein family, however, it is becoming clear that their properties and functions are quite diverse. This review summarizes recent insights into properties of individual selenoproteins such as tissue distribution, subcellular localization, and regulation of expression. Also discussed are potential roles the different selenoproteins play in human health and disease.

455 citations

Journal ArticleDOI
TL;DR: The regulated whole-body pool of selenium is shifted to needy cells and then to vital selenoproteins in them to supply seenium where it is needed, creating a whole- body seleniprotein hierarchy.
Abstract: Selenium is regulated in the body to maintain vital selenoproteins and to avoid toxicity. When selenium is limiting, cells utilize it to synthesize the selenoproteins most important to them, creating a selenoprotein hierarchy in the cell. The liver is the central organ for selenium regulation and produces excretory selenium forms to regulate whole-body selenium. It responds to selenium deficiency by curtailing excretion and secreting selenoprotein P (Sepp1) into the plasma at the expense of its intracellular selenoproteins. Plasma Sepp1 is distributed to tissues in relation to their expression of the Sepp1 receptor apolipoprotein E receptor-2, creating a tissue selenium hierarchy. N-terminal Sepp1 forms are taken up in the renal proximal tubule by another receptor, megalin. Thus, the regulated whole-body pool of selenium is shifted to needy cells and then to vital selenoproteins in them to supply selenium where it is needed, creating a whole-body selenoprotein hierarchy.

380 citations

Journal ArticleDOI
TL;DR: In this paper, a methodological approach for identification, characterization and determination of mass and number concentration of dissolved Ag(I) and silver nanoparticles at environmentally relevant concentrations is presented, where the frequency plots with respect to the intensity measured for each pulse show independent distributions for dissolved silver and Ag nanoparticles, whose profiles are also different.
Abstract: The different behaviours of dissolved silver and silver nanoparticles under ICP-MS single particle detection conditions have been used to differentiate directly between both forms of silver in aqueous samples. Suspensions containing silver nanoparticles at number concentrations below 109 L−1 and/or dissolved Ag(I) are introduced into the ICP-MS by conventional pneumatic nebulization and measured with a time resolution of 5 ms. Each silver nanoparticle is converted in the ICP into a packet of ions, which are detected as a single pulse, whose intensity is proportional to the number of silver atoms in the nanoparticle, whereas dissolved silver produces pulses of averaged constant intensity. The frequency plots with respect to the intensity measured for each pulse show independent distributions for dissolved silver and silver nanoparticles, whose profiles are also different (Poisson and lognormal, respectively). Size limits of detection for pure Ag nanoparticles of 18 nm, equivalent to a silver mass of 32 ag, were obtained. Number concentration limits of detection of 1 × 104 L−1 can be achieved. A methodological approach for identification, characterization and determination of mass and number concentration of dissolved Ag(I) and silver nanoparticles at environmentally relevant concentrations is presented.

331 citations

Journal ArticleDOI
TL;DR: Selenium nanoparticles (SeNPs) represent what the authors believe to be a novel prospect for nutritional supplementation because of their lower toxicity and ability to gradually release selenium after ingestion.

315 citations