Radiofrequency Ablation of Benign Thyroid Nodules and Recurrent Thyroid Cancers: Consensus Statement and Recommendations

Thermal ablation using radiofrequency is a new, minimally invasive modality employed as an alternative to surgery in patients with benign thyroid nodules and recurrent thyroid cancers. The Task Force Committee of the Korean Society of Thyroid Radiology has developed recommendations for the optimal use of radiofrequency ablation for thyroid nodules. These recommendations are based on a comprehensive analysis of the current literature, the results of multicenter studies, and expert consensus

A Prediction Rule to Identify Severe Cases among Adult Patients Hospitalized with Pandemic Influenza A (H1N1) 2009

The purpose of this study was to establish a prediction rule for severe illness in adult patients hospitalized with pandemic influenza A (H1N1) 2009. At the time of initial presentation, the baseline characteristics of those with severe illness (i.e., admission to intensive care unit, mechanical ventilation, or death) were compared to those of patients with non-severe illnesses. A total of 709 adults hospitalized with pandemic influenza A (H1N1) 2009 were included: 75 severe and 634 non-severe cases. The multivariate analysis demonstrated that altered mental status, hypoxia (PaO2/FiO2 ≤ 250), bilateral lung infiltration, and old age (≥ 65 yr) were independent risk factors for severe cases (all P < 0.001). The area under the ROC curve (0.834 [95% CI, 0.778-0.890]) of the number of risk factors were not significantly different with that of APACHE II score (0.840 [95% CI, 0.790-0.891]) (P = 0.496). The presence of ≥ 2 risk factors had a higher sensitivity, specificity, positive predictive value and negative predictive value than an APACHE II score of ≥ 13. As a prediction rule, the presence of ≥ 2 these risk factors is a powerful and easy-to-use predictor of the severity in adult patients hospitalized with pandemic influenza A (H1N1) 2009

Atmospheric levels and distribution of dioxin-like polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) in the vicinity of an iron and steel making plant

Polyurethane foam disk passive air samplers (PAS) were deployed in a steel complex, and in residential and semi-rural areas of a city in Southern Korea between January and April 2006. Dioxin-like polychlorinated biphenyls (PCBs) and polybrominated diphenyl ethers (PBDEs) were monitored to investigate the influence of the steel complex on the residential and semi-rural areas. The average levels of Sigma 12PCB (26.2; 6.1-61.8pg m(-3)) and Sigma 9PBDE (25.2; 9.0-61.6 pg m(-3)) in the steel complex were higher than those of neighboring areas, indicating that the steel complex is a major source of both chemical groups. No significant difference in the congener patterns for the different areas suggests that the study area is commonly affected by the same sources. Elevated air concentrations at the eastern sites of the city and relatively low concentrations at the residential area close to the steel complex were observed. According to air dispersion modeling, the major wind direction plays a key role in determining this spatial distribution of PCBs and PBDEs. Consequently, the levels of these chemicals at the residential area might not be strongly influenced by the emissions from the steel complex. This study suggests that the combination of passive air sampling and air dispersion modeling is a useful tool for assessing source-receptor relationships of persistent organic pollutants (Pops) on a local scale.close343

Influence of a large steel complex on the spatial distribution of volatile polycyclic aromatic hydrocarbons (PAHs) determined by passive air sampling using membrane-enclosed copolymer (MECOP)

Membrane-enclosed copolymer (MECOPs) samplers containing crystalline copolymers of ethylvinylbenzene-divinylbenzene in polyethylene membranes were used to assess the influence of a steel complex on the level and spatial distribution of polycyclic aromatic hydrocarbons (PAHs) in ambient air. MECOPs were deployed at six sites in Pohang, Korea for 37 days (August 9, 2005-September 14, 2005). Fluorene, phenanthrene, anthracene, and fluoranthene were dominant PAHs with the highest contribution of phenanthrene (59%) to the total amount of vapor-phase PAHs. The spatial distribution of total PAHs in the vapor phase ranging from 76 to 1077 ng MECOP-1 and air dispersion modeling suggested that the steel complex was the major PAH source in Pohang. It was revealed that the major wind directions rather than the distance from the steel complex were a significant factor affecting the levels of PAHs at the sampling sites. Finally, we tried to convert MECOP concentrations (ng MECOP-1) to air concentrations (ng m-3) with the modified sampling rates (m3 day-1). This study demonstrates again that passive air samplers are useful tools for spatially resolved and time-integrated monitoring of semivolatile organic compounds (SOCs) in ambient air.close202

Detection of Polychlorinated Biphenyl (PCB-11) in Environmental Samples

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Passive air sampling of persistent organic pollutants in Korea

Atmospheric monitoring is important for the investigation of source and receptor relationships of persistent organic pollutants (POPs). High volume samplers (HiVol), a kind of active air sampler, have been widely used to collect air samples containing POPs. Recently, passive air samplers (PAS) have been developed, and they have several advantages compared with HiVol. In this paper, we introduced the principle, properties, and applications of several types of PAS. Finally, the results of case studies from our group were presented. Since PAS have no electric pump and are much smaller and cheaper than HiVol, they can be used for various scaled monitoring studies. In Korea, we introduced three types of PAS: (1) semipermeable membrane devices (SPMD), (2) polyurethane foam (PUF), and (3) XAD resin-based PAS. The results of monitoring studies using these samplers suggest that PAS are a useful tool for the investigation on the level and distribution of POPs.close

Uptake of Semi-volatile Organic Compounds by Forests

Forests have been known to act as a filter for semi-volatile organic compounds (SOCs). In this study, two methods estimating SOCs fluxes to forest canopies and three processes determining the uptake of SOCs by forests were introduced. An indirect method using bulk samplers is appropriate to estimate long-term fluxes, while a direct method using a vertical gradient of SOCs and the modified Bowen ratio (MBR) method can be used for the estimation of short-term fluxes. The uptake of compounds with intermediate KOA values occurs mainly in the form of kinetically limited gaseous deposition. In addition, a case study carried out in a Canadian mixed deciduous forest was introduced. Vertical profiles and gas/particle partitioning of polycyclic aromatic hydrocarbons (PAHs) indicated that intermediate PAHs (such as phenanthrene, anthracene, and pyrene) were subject to net uptake by the forest canopy in early spring. Based on these results, further studies and applications to Korean forests were proposed.clos

Three-Year Atmospheric Monitoring of Organochlorine Pesticides and Polychlorinated Biphenyls in Polar Regions and the South Pacific

XAD-2 resin based passive air samplers (PAS) were deployed for three one-year periods at the Korean polar and South Pacific research stations at Ny-Alesund (2005-2009), King George Island (2005-2007), and Chuuk (2006-2009) to investigate long-range transport, local sources, and temporal trends of organochlorine pesticides (OCPs) and polychlorinated biphenyls (PCBs). The highest hexachlocyclohexane (HCH) concentration (35.2-78.9 pg.m(-3)) over the entire sampling period was detected at Ny-Alesund, in the Arctic. alpha-HCH was the dominant OCP (31.1-67.1 pg.m(-3)), contributing about 50% of the total OCP load. Additionally, a high and consistent alpha/gamma-HCH ratio was observed at Ny-Alesund. HCHs might reach Arctic sites more easily than other OCPs from surrounding countries through long-range atmospheric transport (LRAT). Interestingly, high levels of the current-use OCP endosulfan-particularly endosulfan-I-were detected at almost all sampling sites, including in Antarctica, ranging 12.2-88.5, 17.7-130, and ND-59.7 pg.m(-3) at King George Island, Ny-Alesund, and Chuuk respectively. Specific OCP and PCB patterns, such as low trans/cis-chlordane ratios and a prevalence of lighter PCB congeners, were observed in all three regions (excepting one site at Ny-Alesund and one site in the South Pacific affected by local sources) during all sampling periods. This indicates that these Polar and remote South Pacific sites are mainly influenced by LRAT. Over the entire sampling period, a decreasing trend of HCHs (alpha- and gamma-HCH) and an increasing trend of endosulfan-I were observed at the Ny-Alesund sites.close242

Estimation of Air Concentrations of PCBs using Passive Air Samplers (PAS) and a Gas/particle Partition Model

Polyurethane foam-disk passive air samplers (PAS) were deployed in a southern area of Korea for three months. The target compounds were 12 coplanar polychlorinated biphenyls (PCBs). The congener profiles measured in this study were the same as those in ambient air and emission gas from the incinerator. A gradient of the total PCBs in different regions (industrial&gt;residential&gt;rural) was observed, suggesting the industrial complex may be an important source of coplanar PCBs. In general, only gas-phase compounds are mainly sequestrated by PAS. In order to estimate the concentration of particle-phase PCBs, a gas/particle partition model was used. A combined result (gas+particle-phase PCBs) was compared with previous results, indicating that the level of coplanar PCBs in our study area is comparable to those in other urban sites in the world. The validation of this method for estimating the total concentration is required through additional backup studies.clos