Development of analytical methods for the determination of 3-hydroxy fatty acids and muramic acid as bacterial markers in airborne particles and settled dust.

Inhalation of airborne bacteria in indoor environments is known to be associated with respiratory diseases. Analytical methods for the determination of 3-hydroxy fatty acids (3-OHFAs) and muramic acid (MA) as chemical markers of gram-negative and gram-positive bacteria, respectively, were developed for airborne particle and dust samples in this study. 3-OHFAs as markers of endotoxin were released and esterified during the hydrolysis process under methanolic acid conditions, and their hydrolysates, i.

Airborne fungal and bacterial microbiome in classrooms of elementary schools during the COVID-19 pandemic period: Effects of school disinfection and other environmental factors.

The aim of the study was to examine the effects of environmental factors including disinfection on airborne microbiome during the coronavirus disease 2019 pandemic, we evaluated indoor and outdoor air collected from 19 classrooms regularly disinfected. Extracted bacterial and fungal DNA samples were sequenced using the Illumina MiSeq™ platform. Using bacterial DNA copy number concentrations from qPCR analysis, multiple linear regressions including environmental factors as predictors were performed.

Physical and biomimetic treatment methods to reduce microplastic waste accumulation.

Background: Since the Covid-19 pandemic in 2019, the use of plastics has increased exponentially, so it is imperative to manage and dispose of these plastic wastes safely.

Objectives: This review focuses on the management strategies governed by the policies of each country to reduce plastic waste through physical collection methods and methods that use eco-imitation technologies.

Results: Thus far, physical treatment methods have been applied to sewage and drinking water treatment.

Reduction in Toxicity of Polystyrene Nanoplastics Combined with Phenanthrene through Binding of Jellyfish Mucin with Nanoplastics.

Mucin (Mu), a biological substance extracted from jellyfish (), was used to reduce the toxic effect of polystyrene nanoplastics (PS-NP) combined with phenanthrene (Phe) in the aquatic environment of zebrafish (), among other aquatic organisms. Mu showed a high binding capacity, as it bound to 92.84% and 92.

Investigation of bacterial and fungal communities in indoor and outdoor air of elementary school classrooms by 16S rRNA gene and ITS region sequencing.

The advent of high-throughput sequencing methods allowed researchers to fully characterize microbial community in environmental samples, which is crucial to better understand their health effects upon exposures. In our study, we investigated bacterial and fungal community in indoor and outdoor air of nine classrooms in three elementary schools in Seoul, Korea. The extracted bacterial 16S rRNA gene and fungal ITS regions were sequenced, and their taxa were identified.

Reduction in Toxicity of Nano-Ag-Polyvinyl-pyrrolidone Using Proteins and Peptides during Zebrafish Embryogenesis.

cells reduce the toxicity of silver nanomaterials to zebrafish () embryos. In this study, we investigated whether protein (HP) and basal disc peptide (Hym176) materials reduce nano-Ag-polyvinylpyrrolidone (N-Ag-PVP) toxicity during embryogenesis of the nanosensitive organism zebrafish. Protein (HP) was extracted from , and peptide (Hym176) was extracted from the hydra basal disc, which is attractive to nanomaterials and related to the immune system.

Trophic transfer of citrate, PVP coated silver nanomaterials, and silver ions in a paddy microcosm.

We used replicated paddy microcosm systems to estimate the tropic transfer of citrate-coated silver nanoparticles (AgNP citrate), polyvinylpyrrolidone (PVP)-coated AgNP (AgNP PVP), and silver ions (AgNO) for 14 days under two exposure regimes (a single high-dose exposure; 60 μg L and a sequential low-dose exposure at 1 h, 4 days and 9 days; 20 μg L × 3 = 60 μg L). Most Ag ions from AgNO had dispersed in the water and precipitated partly on the sediment, whereas the two Ag NPs rapidly coagulated and precipitated on the sediment. The bioconcentration factors (BCFs) of Ag from AgNPs and AgNO in Chinese muddy loaches and biofilms were higher than those of river snails in both exposure conditions.

Trophic transfer of nano-TiO2 in a paddy microcosm: A comparison of single-dose versus sequential multi-dose exposures.

In the present study, replicated paddy microcosm systems were used to investigate the environmental fate and trophic transfer of titanium nanoparticles (NPs) over a period of 14 days. Most TiO2 NPs immediately settled down in the sediment, and high accumulations of nano TiO2 in the sandy loam sediment and biofilm were observed. The test organisms (quillworts, water dropworts, duckweeds, biofilms, river snails, and Chinese muddy loaches) and environmental media (freshwater, sandy loam sediment) were exposed to sequential low doses (2 mg/L at 1 h, 4 days, and 9 days) or a single high-dose (6 mg/L) of TiO2 NPs.

Influence of different types of nanomaterials on their bioaccumulation in a paddy microcosm: a comparison of TiO2 nanoparticles and nanotubes.

We investigated the environmental fate and bioaccumulation of TiO2 nanomaterials in a simplified paddy microcosm over a period of 17 days. Two types of TiO2 nanomaterials, nanoparticles (TiO2-NP) and nanotubes (TiO2-NT), were synthesized to have a negative surface charge. Ti concentrations in the environmental media (water, soil), crops (quillworts, water dropworts), and some lower and higher trophic organisms (biofilms, algae, plant-parasitic nematodes, white butterfly larva, mud snail, ricefish) were quantified after exposure periods of 0, 7, and 17 days.

Photodecomposition of bisphenol A on nanometer-sized TiO2 thin film and the associated biological toxicity to zebrafish (Danio rerio) during and after photocatalysis.

We investigated the relationship between the TiO2 photocatalytic decomposition of bisphenol A and biological toxicity to zebrafish (Danio rerio). TiO2 particles, which prepared using a solvothermal method, were applied to produce a nanometer-sized TiO2 thin film. An alcoholic solution containing the TiO2 particles and an inorganic binder was directly coated on the UV-lamp substrate.