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126 results on '"Kumata, Hidetoshi"'

2. SOURCE APPORTIONMENT OF ATMOSPHERIC AND SEDIMENTARY PAHS FROM KOLKATA, INDIA USING COMPOUND-CLASS-SPECIFIC RADIOCARBON ANALYSIS (CCSRA).

Author

Kumata, Hidetoshi, Uchida, Masao, Saha, Mahua, Saitoh, Shoichi, Mantoku, Kanako, Kobayashi, Toshiyuki, Okuda, Tomoaki, Nakajima, Fumiyuki, Hatakeyama, Shiro, Shibata, Yasuyuki, and Takada, Hideshige

Abstract

Polycyclic aromatic hydrocarbons (PAHs) are major air pollutants that are ubiquitously produced by the combustion of organic materials, and it is extremely important to identify their pollution sources. In this study, molecular fingerprinting and compound class-specific radiocarbon dating (CCSRA) were performed on PAHs from canal sediments and air samples collected in Kolkata, India's third largest city (population approximately 16 million), where PAHs pollution has been a serious problem. Average PAH (Σ12-parent PAHs) concentrations in air samples were 65.1 ng m–3 in summer and 70.9 ng m–3 in winter and in canal sediments were 32.7 µg g–1, which are classified as "very high-level" pollution. Molecular fingerprinting using methyl-PAH/PAH (MPAHs/PAHs) ratios and isomer pair ratios with molecular weights of 178, 202, 228, and 276 suggested that wood and coal combustion were the dominant sources of PAHs in the sediment, and that atmospheric PAHs were influenced by oil combustion in addition to them. The fraction of contemporary carbon (ƒC) of sedimentary PAHs (0.056–0.100), together with the extremely low MPAHs/PAHs ratio results, lead to the conclusion that the major source of the high concentration of PAHs in the canals is from coal combustion. On the other hand, the ƒC of atmospheric PAHs (0.272–0.369) was close to the share of biomass fuels in India's domestic fuel consumption in 2011 (about 35%). Furthermore, the observed ƒC-discrepancy between atmospheric and sedimentary PAHs in the same urban environment was interpreted to give an insight into the loading pathway of PAHs to canal sediments in Kolkata. [ABSTRACT FROM AUTHOR]

Published
2024
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17. The ER cholesterol sensor SCAP promotes CARTS biogenesis at ER–Golgi membrane contact sites

Author

Wakana, Yuichi, Hayashi, Kaito, Nemoto, Takumi, Watanabe, Chiaki, Taoka, Masato, Angulo-Capel, Jessica, Garcia-Parajo, Maria F., Kumata, Hidetoshi, Umemura, Tomonari, Inoue, Hiroki, Arasaki, Kohei, Campelo, Felix, Tagaya, Mitsuo, Wakana, Yuichi, Hayashi, Kaito, Nemoto, Takumi, Watanabe, Chiaki, Taoka, Masato, Angulo-Capel, Jessica, Garcia-Parajo, Maria F., Kumata, Hidetoshi, Umemura, Tomonari, Inoue, Hiroki, Arasaki, Kohei, Campelo, Felix, and Tagaya, Mitsuo

Abstract

In response to cholesterol deprivation, SCAP escorts SREBP transcription factors from the endoplasmic reticulum to the Golgi complex for their proteolytic activation, leading to gene expression for cholesterol synthesis and uptake. Here, we show that in cholesterol-fed cells, ER-localized SCAP interacts through Sac1 phosphatidylinositol 4-phosphate (PI4P) phosphatase with a VAP–OSBP complex, which mediates counter-transport of ER cholesterol and Golgi PI4P at ER–Golgi membrane contact sites (MCSs). SCAP knockdown inhibited the turnover of PI4P, perhaps due to a cholesterol transport defect, and altered the subcellular distribution of the VAP–OSBP complex. As in the case of perturbation of lipid transfer complexes at ER–Golgi MCSs, SCAP knockdown inhibited the biogenesis of the trans-Golgi network–derived transport carriers CARTS, which was reversed by expression of wild-type SCAP or a Golgi transport–defective mutant, but not of cholesterol sensing–defective mutants. Altogether, our findings reveal a new role for SCAP under cholesterol-fed conditions in the facilitation of CARTS biogenesis via ER–Golgi MCSs, depending on the ER cholesterol., Peer Reviewed, Postprint (published version)

Published
2020

20. The ER cholesterol sensor SCAP promotes CARTS biogenesis at ER–Golgi membrane contact sites

Author

Wakana, Yuichi, primary, Hayashi, Kaito, additional, Nemoto, Takumi, additional, Watanabe, Chiaki, additional, Taoka, Masato, additional, Angulo-Capel, Jessica, additional, Garcia-Parajo, Maria F., additional, Kumata, Hidetoshi, additional, Umemura, Tomonari, additional, Inoue, Hiroki, additional, Arasaki, Kohei, additional, Campelo, Felix, additional, and Tagaya, Mitsuo, additional

Published
2020
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21. Preparation of Horizontal Miniature TLC Developing Chamber for Ultra-thin Layer Chromatography

Author

IMAZAKI, Ryunosuke, primary, KONDOH, Keita, additional, TANI, Natsumi, additional, AOKI, Motohide, additional, KUMATA, Hidetoshi, additional, UCHIDA, Tatsuya, additional, NAGANAWA, Tsuyoshi, additional, SHIMADA, Taisuke, additional, TAGUCHI, Yoshihiko, additional, SATO, Hiroaki, additional, YASUI, Takao, additional, and UMEMURA, Tomonari, additional

Published
2020
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23. Determination of 2-(4-Morpholinyl)benzothiazole in environmental samples by a gas chromatograph equipped with a flame photometric detector

Author

Kumata, Hidetoshi, Takada, Hideshige, and Ogura, Norio

Subjects
Gas chromatography -- Usage, Photometry -- Usage, Chemicals -- Evaluation, Chemistry
Abstract

2-(4-Morpholinyl)benzothiazole (24MoBT) exists in automobile tire rubber as an impurity of a vulcanization accelerator and has been proposed as a potential molecular marker of street runoff (Spies, R. B.; Andresen, B. D.; Rice, D. W., Jr. Nature 1987, 327, 697-699). The present paper describes an analytical method for 24MoBT in environmental samples (e.g., street dusts and river sediments) by gas chromatography. The method relies upon extraction with a 6:4 (v/v) mixture of benzene and methanol, purification by acid extraction, and adsorption column chromatography, followed by determination using capillary GC equipped with a sulfur-selective detector (i.e., FPD). The recovery of 24MoBT for the entire procedure was 85%, and the relative standard deviation for four replicated analyses was 1.5%. The detection limit was 0.08 ng injected 24MoBT, corresponding to 0.20 ng/g of dry sample. The selectivity and sensitivity of the present method permit the determination of 24MoBT at the trace levels (e.g., [similar to] ng/g) encountered in environmental samples. 24MoBT concentrations in various environmental samples are also reported.

Published
1996

36. Distribution of polycyclic aromatic hydrocarbons (PAHs) in rivers and estuaries in Malaysia: a widespread input of petrogenic PAHs

Author

Zakaria, Mohamad Pauzi, Takada, Hideshige, Tsutsumi, Shinobu, Ohno, Kei, Yamada, Junya, Kouno, Eriko, Kumata, Hidetoshi, Zakaria, Mohamad Pauzi, Takada, Hideshige, Tsutsumi, Shinobu, Ohno, Kei, Yamada, Junya, Kouno, Eriko, and Kumata, Hidetoshi

Abstract

This is the first publication on the distribution and sources of polycyclic aromatic hydrocarbons (PAHs) in riverine and coastal sediments in South East Asia where the rapid transfer of land-based pollutants into aquatic environments by heavy rainfall and runoff waters is of great concern. Twenty-nine Malaysian riverine and coastal sediments were analyzed for PAHs (3−7 rings) by gas chromatography mass spectrometry. Total PAHs concentra tions in the sediment ranged from 4 to 924 ng/g. Alkylated homologues were abundant for all sediment samples. The ratio of the sum of methylphenanthrenes to phenanthrene (MP/P), an index of petrogenic PAHs contribution, was more than unity for 26 sediment samples and more than 3 for seven samples for urban rivers covering a broad range of locations. The MP/P ratio showed a strong correlation with the total PAHs concentrations, with an r2 value of 0.74. This ratio and all other compositional features indicated that Malaysian urban sediments are heavily impacted by petrogenic PAHs. This finding is in contrast to other studies reported in many industrialized countries where PAHs are mostly of pyrogenic origin. The MP/P ratio was also significantly correlated with higher molecular weight PAHs such as benzo[a]pyrene, suggesting unique PAHs source in Malaysia which contains both petrogenic PAHs and pyrogenic PAHs. PAHs and hopanes fingerprints indicated that used crankcase oil is one of the major contributors of the sedimentary PAHs. Two major routes of inputs to aquatic environments have been identified: (1) spillage and dumping of waste crankcase oil and (2) leakage of crankcase oils from vehicles onto road surfaces, with the subsequent washout by street runoff. N-Cyclohexyl-2-benzothiazolamine (NCBA), a molecular marker of street dust, was detected in the polluted sediments. NCBA and other biomarker profiles confirmed our hypothesis of the input from street dust contained the leaked crankcase oil. The fingerprints excluded crude oil, f

Published
2002

50. Radiocarbon-based source apportionment of black carbon (BC) in PM10 aerosols from residential area of suburban Tokyo

Author

Uchida, Masao, Kumata, Hidetoshi, Koike, Yasuyo, Tsuzuki, Mikio, Uchida, Tatsuya, Fujiwara, Kitao, and Shibata, Yasuyuki

Subjects
*CARBON isotopes, *CARBON-black, *AEROSOLS, *SUBURBS, *ACCELERATOR mass spectrometry, *POLYCYCLIC aromatic hydrocarbons, *FOSSIL fuels
Abstract

Abstract: The AMS technique was applied to analyse black carbon (BC), total organic carbon (TOC), and previously reported polycyclic aromatic hydrocarbons (PAHs) in PM10 aerosols from a residential area, suburban Tokyo, to determine natural abundance of radiocarbon (14C), an ideal tracer to distinguish fossil fuel (14C-free) from modern biomass combustion sources of pyrolytic products. The 14C concentrations in BC, isolated using the CTO-375 method, were 42% and 30% pMC (in terms of percent Modern Carbon: pMC) in summer and winter, respectively. The 14C concentrations in BC were also compared with those of compound-class specific 14C content of PAHs previously reported for the same samples: they were 45% and 33% pMC in summer and winter, respectively. The 14C signals of BC were identical to those of high molecular weight (MW⩾226, 5–6 rings) PAHs. The resemblance between 14C signals of BC and PAHs can be referred as a ‘certificate’ for the validity of the BC isolation method employed in this study. Also, it suggests that 14C-BC approach can be a surrogate for PAHs specific 14C analyses to monitor seasonal source variation of combustion-derived pyrolytic products. On the other hand, 14C contents of total organic carbon in 2004 were 61% and 42% pMC in summer and winter, respectively. This is likely attributed to higher contribution of plant activity in summer. [Copyright &y& Elsevier]

Published
2010
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