Occurrence, distribution, and potential exposure risk of organophosphate flame retardants in house dust in South Korea.

Concentrations of organophosphate flame retardants (OPFRs), which are used in various plastic products, were analyzed in house dust samples collected from three Korean cities (Suwon, n = 23; Jeonju, n = 20; Kunsan, n = 42). OPFRs, including tris (2-chloroethyl) phosphate (TCEP), tris (2-chloroisopropyl) phosphate (TCPP), and tris (1,3-dichloro-2-propyl) phosphate (TDCPP), were detected in 95%-100% of the samples analyzed, suggesting the widespread use of these compounds in Korea. The levels of TCEP, TCPP, and TDCPP in Suwon, Jeonju, and Kunsan ranged from the limit of quantitation to 46,000, 28,000, and 2400 ng/g, respectively. The concentrations of all OPFRs were significantly higher in house dust samples from Suwon than from Jeonju and Kunsan; this is likely due to the increased use of these compounds in Suwon, which may be associated with the number, volume, and variety of household products in homes. In Korean homes, the estimated daily intake (EDI) of OPFRs through house dust ingestion was lower than the guideline values; however, the EDI of OPFRs for toddlers was 30-fold greater than for adults, suggesting a limited risk to human health. This is the first comprehensive study of the occurrence and distribution of OPFRs in house dust in Korea.

Effects of picosecond laser on the multi-colored tattoo removal using Hartley guinea pig: A preliminary study.

Picosecond lasers have emerged as the leading technology for tattoo removal due to their shorter pulse lengths. To clarify the features of picosecond lasers, we compared picosecond and nanosecond lasers in their ability to remove multi-colored tattoo in an animal model. We first compared a nanosecond quality-switched Nd:YAG laser with picosecond Alexandrite and quality-switched Nd:YAG lasers and then the picosecond quality-switched Nd:YAG laser with the picosecond Alexandrite laser, using a guinea pig model. The colors in the tattoos included red, orange, yellow, green, blue, and black. Guinea pigs were treated for one session with each type of laser. The clearance of pigmentation and local reactions were evaluated based on clinical photographic assessment, quantitative assessment using a colorimeter, histopathology, and electron microscopic examination before laser treatment, immediately after, and at 3 weeks after the treatment. Regardless of pulse duration, a 532-nm laser was the most effective in clearing red, orange, and yellow pigments, although the overall effect and safety was better with the picosecond 532 nm laser. A picosecond 755 nm laser demonstrated excellent efficacy in removing only green and blue pigments. a picosecond 1064 nm laser demonstrated some effects on non-black colored tattoos. In terms of safety, picosecond lasers produced less tissue injury than nanosecond lasers. Conclusively, picosecond lasers are more effective and safer than nanosecond lasers.

Effects of pore structure on the high-performance capacitive deionization using chemically activated carbon nanofibers.

Capacitive deionization (CDI) electrodes were constructed from activated carbon fibers prepared using electrospinning and chemical activation. The CDI efficiencies of these electrodes were studied as a function of their specific surface areas, pore volumes and pore sizes via salt ion adsorption. The specific surface areas increased approximately 90 fold and the pore volume also increased approximately 26 fold with the use of greater amounts of the chemical activation agent. There was a relative increase in the mesopore fraction with higher porosity. A NaCI solution was passed through a prepared CDI system, and the salt removal efficiency of the CDI system was determined by the separation of the Na+ and Cl- ions toward the anode and cathode. The CDI efficiency increased with greater specific surface areas and pore volumes. In addition, the efficiency per unit pore volume increased with a reduction in the micropore fraction, resulting in the suppressed overlapping effect. In conclusion, the obtained improvements in CDI efficiency were mainly attributed to mesopores, but the micropores also played an important role in the high-performance CDI under conditions of high applied potential and high ion concentrations.