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2-Bromopropane (2-BP) is a colorless liquid at room temperature and is used in closed systems in factories, mainly as an intermediate for medicines, pesticides, and other chemicals. However, the carcinogenicity of 2-BP is still unknown. The CByB6F1-Tg(HRAS)2Jic (rasH2) transgenic mouse model has been established as an alternative to long-term studies (1.5 years-lifetime) to detect carcinogenicity in as short a time as six months. We performed a 26-week inhalation exposure study of 2-BP using the rasH2 mouse model. Male and female rasH2 mice were exposed to 0, 67, 200, or 600 ppm of 2-BP for 6 h/day, 5 days/week for 26 weeks. All tissues and blood were collected and subjected to biological and histopathological analyses. The results showed a concentration-dependent increase in lung tumor development in male and female rasH2 mice exposed by inhalation to 2-BP, which was significant by Peto's and Poly-3 trend tests. Furthermore, in male rasH2 mice, 2-BP was found to be a testicular toxin. This study is the first to demonstrate that 2-BP is carcinogenic in male and female mice and a testicular toxin in male mice using the rasH2 mouse model., (© 2023. The Author(s).)

With the rapid development of alternative methods based on the spirit of animal welfare, the publications of animal studies evaluating endpoints such as cancer have been extremely reduced. We performed a 26-week inhalation exposure studies of titanium dioxide nanoparticles (TiO 2 NPs) using CByB6F1-Tg(HRAS)2Jic (rasH2) mice model for detecting carcinogenicity. Male and female rasH2 mice were exposed to 2, 8 or 32 mg/m 3 of TiO 2 NPs for 6 h/day, 5 days/week for 26 weeks. All tissues and blood were collected and subjected to biological and histopathological analyses. TiO 2 NPs exposure induced deposition of particles in lungs in a dose-dependent manner in each exposure group. Exposure to TiO 2 NPs, as well as other organs, did not increase the incidence of lung tumors in any group, and pulmonary fibrosis and pre-neoplastic lesions were not observed in all groups. Finally, the cell proliferative activity of alveolar epithelial type 2 cells was examined, and it was not increased by exposure to TiO 2 NPs. This is the first report showing the lack of pulmonary fibrogenicity and carcinogenicity (no evidence of carcinogenic activity) of TiO 2 NPs in 26-week inhalation study in rasH2 mice exposed up to 32 mg/m 3 , which is considered to be a high concentration., (© 2022. The Author(s).)

Designing a high-capacity positive electrode material is critical for the advancement of lithium-ion batteries. Sulfurized polyethylene glycol (SPEG), containing ca. 61 wt% of sulfur, is a promising positive electrode material that exhibits a large initial discharge capacity of more than 800 mAh g -1 . In this study, we present the local structure and electrochemical performances of SPEG. A high-energy X-ray total scattering experiment revealed that sulfur in SPEG is predominantly fragmented and bound to carbon atoms. The changes in the physicochemical properties of SPEG due to heat treatment with nitrogen gas at various temperatures were investigated using thermogravimetric analysis, Raman spectroscopy, X-ray absorption near edge structure, and extended X-ray absorption fine structure. Comparing the electrochemical performances of SPEG after heat treatment at various temperatures, it was found that S-S and C=S bonds contribute to the overall electrochemical performance of SPEG.

Using sodium, instead of lithium, in rechargeable batteries is a way to circumvent the lithium's resource problem. The challenge is to find an electrode material that can reversibly undergo redox reactions in a sodium-electrolyte at the desired electrochemical potential. We proved that indigo carmine (IC, 5,5'-indigodisulfonic acid sodium salt) can work as a positive-electrode material in not only a lithium-, but also a sodium-electrolyte. The discharge capacity of the IC-electrode was ~100 mAh g(-1) with a good cycle stability in either the Na or Li electrolyte, in which the average voltage was 1.8 V vs. Na(+)/Na and 2.2 V vs. Li(+)/Li, respectively. Two Na ions per IC are stored in the electrode during the discharge, testifying to the two-electron redox reaction. An X-ray diffraction analysis revealed a layer structure for the IC powder and the DFT calculation suggested the formation of a band-like structure in the crystal.