Temporal dynamics of public transportation ridership in Seoul before, during, and after COVID-19 from urban resilience perspective.

We delve into the temporal dynamics of public transportation (PT) ridership in Seoul, South Korea, navigating the periods before, during, and after the COVID-19 pandemic through a spatial difference-in-difference model (SDID). Rooted in urban resilience theory, the study employs micro-level public transportation card data spanning January 2019 to December 2023. Major findings indicate a substantial ridership decline during the severe COVID impact phase, followed by a period in the stable and post-COVID phases.

Exposure to airborne particulate matter induces renal tubular cell injury : the role of vitamin D signaling and renin-angiotensin system.

Background: Exposure to air pollution can interfere with the vitamin D endocrine system. This study investigated the effects of airborne particulate matter (PM) on renal tubular cell injury and explored the underlying mechanisms.

Methods: HK-2 human renal proximal tubule cells were treated with PM with or without 1,25(OH)D analog, 19-Nor-1,25(OH)D (paricalcitol, 10 nM) for 48 h.

Effectiveness of activated carbon disk for the analysis of iodine in water samples using wavelength dispersive X-ray fluorescence spectrometry.

A novel approach using wavelength dispersive X-ray fluorescence (WDXRF) spectrometry combined with an activated carbon (AC) disk was developed for the determination of total iodine concentrations in water samples. Dissolved iodine species (i.e.

Formation of dimethyldithioarsinic acid in a simulated landfill leachate in relation to hydrosulfide concentration.

Dimethyldithioarsinic acid (DMDTA(V)), present in such intense sources as municipal landfill leachate, has drawn a great deal of attention due to its abundant occurrence and different aspect of toxicity. The hydrosulfide (HS(-)) concentration in leachate was studied as a major variable affecting the formation of DMDTA(V). To this end, the HPLC-ICPMS system equipped with the reversed-phase C18 column was used to determine DMDTA(V).

A simplified analysis of dimethylarsinic acid by wavelength dispersive X-ray fluorescence spectrometry combined with a strong cation exchange disk.

Dimethylarsinic acid (DMA(V)) was pre-concentrated from water samples using a strong cation exchange (SCX) disk functionalized with sulfonic groups, before being analyzed by wavelength dispersive X-ray fluorescence spectrometry (WDXRF). The adsorption of DMA(V) occurred preferentially on the surface of the SCX disk, regardless of pH levels, probably due to interactions with the sulfonic functional groups. However, no other arsenic species, such as arsenate (iAs(V)), arsenite (iAs(III)), and monomethylarsonic acid (MMA(V)), were retained.

Characteristics of atmospheric hydrogen peroxide variations in Seoul megacity during 2002-2004.

Atmospheric hydrogen peroxides (H(2)O(2)) and methyl hydroperoxide (CH(3)OOH) were measured in Seoul, the capital of South Korea. Experiments were performed for several days almost every month from January 2002 to April 2004. Gaseous hydroperoxide was collected in aqueous solution and determined by HPLC-fluorescence method.