Publications by authors named "Tsuyoshi Kawakami"

Workers and employers in the informal economy are often outside the scope of legal frameworks of occupational safety and health (OSH) service in South Asia. The present study aimed to find practical support measures to improve their safety and health. International Labour Organization's participatory training activities in five selected informal economy workplaces comprising waste collection and recycling in India, sewage cleaning in Pakistan, home-based manufacturing in Nepal, small-scale construction in Nepal, and cotton farming in India were studied.

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Henna is a plant-based dye obtained from the powdered leaf of the pigmented plant Lawsonia inermis, and has often been used for grey hair dyeing, treatment, and body painting. As a henna product, the leaves of Indigofera tinctoria and Cassia auriculata can be blended to produce different colour variations. Although allergy from henna products attributed to p-phenylenediamine, which is added to enhance the dye, is reported occasionally, raw material plants of henna products could also contribute to the allergy.

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In Japan, the use of frame retardants [tris(2,3-dibromopropyl)phosphate: TDBPP and bis(2,3-dibromopropyl)phosphate: BDBPP] in several household textile products is banned under the "Act on the Control of Household Products Containing Harmful Substances." As the official analytical methods for testing these substances have not been revised for over 42 years, several issues such as the using of harmful reagents, have been pointed out. Therefore, we developed a new method to revise the official method in our previous study.

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Tris(1-aziridinyl)phosphine oxide (APO) used as flame retardant in textile products, such as curtains, carpets, and sleeping clothes, is prohibited in Japan under the "Act on the Control of Household Products Containing Harmful Substances." This study developed a GC-MS-based method to quantify APO more accurately and safely than the current official method. The APO in textile products was extracted with methanol, the extract was replaced with acetone instead of hexane as previously reported, and purified by florisil cartridge column.

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Background: In recent years, due to the global shortage of helium gas, the development of gas chromatography (GC) analytical methods using alternatives to helium carrier gases is necessary.

Objective: The objective of this study was to examine the applicability of hydrogen and nitrogen as alternative carrier gases using the test method for azo compounds in the Act on Control of Household Products Containing Harmful Substances of Japan.

Method: The gas chromatograph mass spectrometer (GC-MS) analytical method using hydrogen and nitrogen as alternative carrier gases was compared with a method using helium for 26 primary aromatic amines (PAAs) originated from azo dyes.

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Polycyclic aromatic hydrocarbons (PAHs) in creosote products used for wood preservation are regulated in Japan. Although the analytical method for this regulation has been stipulated by law, two main problems have been highlighted, namely the use of dichloromethane, a potential carcinogen, as a solvent and inadequate purification. Therefore, an analytical method to solve these problems was developed in this study.

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The objectives of this study were to develop a novel analytical method for quantifying vinyl chloride (VC) emitted from aerosol products, to provide analytical data on VC in aerosol products, and to evaluate consumer VC exposure by aerosol products. Our quantitative method involves absorbing VC into dimethyl sulfoxide and analyzing it using headspace gas chromatography/mass spectrometry. The correlation coefficients of the VC calibration curves were ≥ 0.

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Transient Receptor Potential Ankyrin 1 (TRPA1), which is expressed in the airways, has causative and exacerbating roles in respiratory diseases. TRPA1 is known as a target of sick building syndrome-related air pollutants, such as formaldehyde. Thus, an in vitro TRPA1 activation assay would be useful for predicting the potential risk of air pollution.

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Amino acid derivative reactivity assay (ADRA) is an assay for assessing the skin sensitization potential of chemicals by evaluating the reactivity of nucleophilic reagents that mimic skin proteins. -(2-(1-Naphthyl)acetyl)-l-cysteine (NAC) and α--(2-(1-naphthyl)acetyl)-l-lysine (NAL), used as nucleophilic reagents, are small-molecule derivatives of two different amino acids, each with a naphthalene ring attached. The rate of decrease in the amount of NAC or NAL in the reaction solution is evaluated in this assay as an indicator of the test substance's skin sensitization ability.

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Background: Several primary aromatic amines (PAAs) have been designated carcinogenic or suspected of carcinogenicity. Several kinds of PAAs may occur either via the reduction of azo compounds or as impurities in azo colorants or other agents.

Objective: An analytical method was developed and applied to determine whether certain PAAs are present as impurities in synthetic organic colorants.

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Article Synopsis
  • In August 2021, certain batches of the Moderna COVID-19 vaccine were recalled in Japan due to the discovery of foreign particles in some vaccine vials.
  • Analysis revealed that the foreign particles were made of stainless steel and varied in size from under 50 μm to 548 μm.
  • Investigations indicated that the particles were also present in vials stored by the manufacturer, leading to concerns that some individuals may have already received contaminated doses, prompting a discussion on prevention strategies.
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Although the health effects of artificial turf fillings have been investigated in Europe and the United States, the actual situation in Japan is unclear. To address this issue, the concentrations of 46 polyaromatic hydrocarbons (PAHs) and related compounds in rubber infills were analyzed prior to their use in synthetic turf fields in Japan. Based on information obtained from the sample suppliers, the investigated samples were divided into five categories: discarded tires, industrial rubber, combinations of these products or unidentified components (mixture/unknown), synthetic rubber specifically manufactured for synthetic turf, and special-purpose thermoplastic elastomers (TPEs).

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Article Synopsis
  • This study investigates how the SARS-CoV-2 virus and a model virus, bovine coronavirus (BCoV), survive on different surfaces, observing that non-porous surfaces retain infectious virus longer than porous ones.
  • On porous materials like non-woven masks, the virus takes longer to decrease to detectable levels compared to non-porous surfaces, but overall, both viruses showed reduced infectious levels over time.
  • The research also found that RNA from SARS-CoV-2 can persist on surfaces beyond the time the virus remains infectious, indicating the need for careful measurement of viral titers to avoid misestimating contamination risks.
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We evaluated the total content of 28 metals in synthetic turf rubber granule infill and performed extraction tests using four types of simulated biofluids to assess the health effects of synthetic turf crumb rubbers used in Japan. The highest median metal concentration was obtained for Zn, with median concentrations above 100 μg/g, followed by Al, Fe, and Mn. The highest median Pb concentration was 19.

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We have conducted several studies with an overall goal of assessing the effects of rubber granules in synthetic turf on the health of athletes, other players, and children in Japan. As part of these studies, the investigation reported herein was aimed at analyzing the concentrations of rubber additives (vulcanization accelerators, antioxidants, and cross-linking agents) and related chemicals in 46 rubber infills prior to their use in synthetic turf fields in Japan. Of the 36 chemicals selected for targeted analysis, 26 were detected and quantified.

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There has been extensive studies on the composition of tires and industrial rubber. However, there is insufficient information on volatile organic compounds (VOCs) emitted from rubber granule products used to fill synthetic turf fields. In this study, we applied a passive sampling method for assessing the VOCs emitted from rubber granule products used for filling synthetic turf fields.

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The effect of nanoparticle type, shape, as well as primary and secondary particle size on toxicity remains poorly characterized. In this study, suspensions of nickel oxide (NiO) nanoparticles with the same primary particle size (< 50 nm) but different secondary particle sizes were prepared, and their cytotoxicity was investigated. A planetary ball mill wet nanopulverizer with zirconium milling balls of decreasing sizes (φ: 0.

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Since the Coronavirus Disease 2019 (COVID-19) pandemic began, people have been wearing face masks for many hours every day. As these face masks are in contact with the skin, it is important to pay more attention to their quality and safety. This study examined the concentration of free formaldehyde in 90 non-medical face masks and related products (33 nonwoven, 30 woven cloth, 12 polyurethane, and 15 related products) because formaldehyde is a common contact allergen in textile products.

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The use of flame retardants, namely bis(2,3-dibromopropyl) phosphate (BDBPP) and tris(2,3-dibromopropyl) phosphate (TDBPP), in textile products such as curtains, carpets and sleeping clothes is banned in Japan under the 'Act on the Control of Household Products Containing Harmful Substances'. Herein, we developed a GC-MS based method to quantify these compounds with greater accuracy and safety than the current official method. For accurate and sensitive quantification, deuterated compounds, BDBPP-d and TDBPP-d, were used as surrogate standards.

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The amino acid derivative reactivity assay (ADRA) is an in chemico alternative assay for skin sensitization listed in OECD test guideline 442C. ADRA evaluates the reactivity of sensitizers to proteins, which is key event 1 in the skin sensitization adverse outcome pathway. Although the current key event 1 evaluation method is a simple assay that evaluates nucleophile and test chemical reactivity, mixtures of unknown molecular weights cannot be evaluated because a constant molar ratio between the nucleophile and test chemical is necessary.

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Amino acid derivative reactivity assay (ADRA) for skin sensitization was adopted as an alternative method in the 2019 OECD Guideline for the Testing of Chemicals (OECD TG 442C). The molar ratio of the nucleophilic reagent to the test chemicals in the reaction solution was set to 1:50. Imamura et al.

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