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The Republic of Korea has a high prevalence of hepatitis B virus (HBV) infection, and the policies concerning costly antiviral medication have been revised recently. However, in the past 10 years, no related research on costs has been conducted. The objective of this study was to estimate the economic burden of viral hepatitis B and determine the trend of changes in its costs between 2002 and 2015. Claims data from the National Health Insurance Service were used. To identify viral hepatitis B cases, the ICD-10th code B16, B17.0, B18.0 and B18.1 were used based on a primary diagnosis. This study was conducted from a societal perspective regarding both direct and indirect costs. Annual costs were adjusted for inflation by calculations based on the 2015 costs. The number of patients with viral hepatitis B increased from 213 758 in 2002 to 342 672 in 2015. The total socio-economic costs increased from 127.1 million USD in 2002 to 459.1 million USD in 2015, mainly due to the increase in pharmaceutical costs, which accounted for the largest proportion of total costs since 2009-220.5 million USD in 2015, which was ~15 times higher than that in 2002. The healthcare costs for viral hepatitis B accounted for 0.13% of the national health expenditure in 2002, increasing to 0.31% in 2015. The economic burden of viral hepatitis B has increased in the Republic of Korea. It is therefore essential to reduce the healthcare costs of HBV infection by establishing an effective management policy.

Surface-wetting properties are an important cause of changing the groundwater and two-phase fluid flows. Various factors affecting the surface wettability were investigated in a parallel-walled glass fracture with non-aqueous phase liquid (NAPL) (gasoline, diesel, trichloroethylene, and creosote) wetted surfaces. First, the effect of the duration of NAPL exposure on wettability change was considered at pre-wet fracture surfaces using the various NAPL species, and the result showed that the surface became hydrophobic after the exposure time of NAPL exceeded 2000 min. Second, the initial wetting state of the surface affected the timing when the wettability change begins as well as the extent of the wettability change in an NAPL-wetted rock fractures. Under the dry condition, the wettability change was completed within a very short time of exposure to NAPL (~5 min), and then it finally reached the intermediate and weakly NAPL wetting (contact angle of 118°). Under the pre-wet condition, a relatively long time of exposure (~5000 min) was needed to observe the obvious change of the surface wettability, which was changed up to strongly NAPL wetting (contact angle of 142°). Third, the wettability changed by NAPL exposure was stable and maintained for a long time, regardless of water flushing rate and temperature. Finally, the wettability change by the exposure of NAPL on parallel fracture surfaces was evaluated at various groundwater flow velocities. Result showed that groundwater flow velocity has an important impact upon measured contact angle. Although fracture surfaces were exposed to NAPL at the low groundwater flow velocity, the wettability was not changed from hydrophilic to hydrophobic when the contact time between NAPL and mineral surfaces was not sufficient owing to the pulse-type movement of NAPL. This implies that the variation of exposure pattern due to groundwater flow on the wettability change can be an important factor affecting the wettability change of fracture surface and migration behaviour at natural fractured rock aquifers in case of NAPL spill. Copyright © 2015 John Wiley & Sons, Ltd.

To analyze the effect of filter pack arrangement on the hydraulic properties and the well efficiency of a well design, a step drawdown was conducted in a sand-filled tank model. Prior to the test, a single filter pack (SFP), granule only, and two dual filter packs (DFPs), type A (granule-pebble) and type B (pebble-granule), were designed to surround the well screen. The hydraulic properties and well efficiencies related to the filter packs were evaluated using the Hazen's, Eden-Hazel's, Jacob's, and Labadie-Helweg's methods. The results showed that the hydraulic properties and well efficiency of the DFPs were higher than those of a SFP, and the clogging effect and wellhead loss related to the aquifer material were the lowest owing to the grain size and the arrangement of the filter pack. The hydraulic conductivity of the DFPs types A and B was about 1.41 and 6.43 times that of a SFP, respectively. In addition, the well efficiency of the DFPs types A and B was about 1.38 and 1.60 times that of the SFP, respectively. In this study, hydraulic property and well efficiency changes were observed according to the variety of the filter pack used. The results differed from the predictions of previous studies on the grain-size ratio. Proper pack-aquifer ratios and filter pack arrangements are primary factors in the construction of efficient water wells, as is the grain ratio, intrinsic permeability (k), and hydraulic conductivity (K) between the grains of the filter packs and the grains of the aquifer.

In this study, a UV-curable glycidyl methacrylate–methyl methacrylate (GMA–MMA) copolymer with an acrylic acid (AA) pendant group was synthesized via simple radical polymerization. The procedure for forming the backbone (GMA–MMA) consisted of two polymerization steps; step 1 was performed under excess solvent and step 2 involved the introduction of additional monomer except solvent owing to the high degree of polymerization at a minimum solvent. The use of these separate steps during GMA–MMA polymerization improved the degree of conversion (DC) during polymerization optimization. The DC was estimated using Fourier transform infrared (FTIR) spectroscopy and proton nuclear magnetic resonance (H NMR) spectroscopy. The behaviors of AA and GMA in the copolymer were interpreted on the basis of the glass transition temperature (Tg) and the molecular weight (Mw).The hardness and flexibility of the film were monitored with respect to the molar ratios of GMA/MMA and AA/GMA, respectively; the optimized molar ratios of GMA/MMA and AA/GMA were 1.6 and 1.8, respectively. The copolymer fabricated in this study was applied as a UV-curable thin layer via a coating method. © 2011 Wiley Periodicals, Inc. Adv Polym Techn 31: 271–279, 2012; View this article online at wileyonlinelibrary.com. DOI 10.1002/adv.20250

More than 80 percent of US growth between 1950 and 1993 can be attributed to transition dynamics (increases in R&D intensity and educational attainment), with less than 20 percent of growth deriving from population growth. Similarly, growth accounting shows that 80 percent of economic growth in Korea can be attributed to transition dynamics. However, the specific factors that have moved Korea far from its steady state are significantly different from the factors that have done so for the USA. In addition to the growth rates of the two countries, we also analyzed the (steady-state) level of output per worker to determine where the Korean economy is headed relative to the USA. In 1960, Korea was characterized as poor (0.111) relative to its own steady state (0.765), and incomes were at 11.1 percent of those in the USA. Since then, however, Korea has been growing more rapidly than the USA. In our analysis, we also consider the extreme case where total factor productivity levels converge completely. Interestingly, in this case, the USA and Korea exhibit unconditional convergence similar to what is generally observed in the OECD. As the economy approaches the steady-state income level, however, the growth rate of output per capita will decline.

To enhance nitrogen removal in an existing microbial contact oxidation (MCO) system with a treatment capacity of 900 m3/d, an upflow multilayer bioreactor (UMBR) was chosen as a preanoxic reactor for the removal of organic matter and nitrate. The removal performance of the retrofitted plant was evaluated during the startup phase at a low temperature in winter. The high removal (>80%) of organic matter and suspended solids in the UMBR provided stable nitrification conditions in the MCO system, as a result of the substantial reduction in organic matter and solids loaded onto the MCO system. This treatment system showed a stable nitrogen removal efficiency of 75.3%, even in the low temperature range 7 to 10 degrees C. Phosphorus was completely removed by chemical precipitation. Production rates of excess sludge, as a function of the loads of influent flowrate and biological oxygen demand (BOD), were 0.022 kg dry solid/m3 wastewater and 0.132 kg dry solid/kg BOD.

BACKGROUND: Non-uniform distribution of pore size and depth of porous Si chip for a Fabry–Perot interferometer, in a previous study, led to relatively low sensitivity with poor reproducibility when its surface was immobilized with calyx crown derivative (Prolinker A). In this study, porous anodized aluminium oxide (AAO) was used as an alternative biochip substrate for detecting β-galactosidase, and chip fabrication and surface functionalization methods were optimized. RESULTS: According to structural and spectral analysis of the AAO surface, an optimal operating voltage for anodization was determined as 40 V, which gave the best uniformity in pore size (about 30 nm) and fringe pattern. The ΔEOT (difference in effective optical thickness) showed a linear relationship (R2 = 0.9932) with β-galactosidase concentration in the range 0.05–5 units enzyme mL−1, corresponding to 0.07–7.0 µg protein mL−1. CONCLUSIONS: With uniformly porous AAO immobilized with Prolinker A, sensitivity was enhanced about 200 times compared with the lowest detection concentration of 10 units mL−1 with the porous Si chip used in the previous study. Copyright © 2007 Society of Chemical Industry

Photocatalytic disinfection using TiO2 particles suspended in a reactor involves two major problems; the exponential decrease of light availability due to the scattering of UV light by particles themselves and the difficulty of recycling particles. To resolve these problems, scratched optical-fibres, inserted in glass tubes were used to diffuse UV light uniformly in a reactor. Comparative disinfection studies using these optical-fibres were done in both cases of suspended and immobilised photocatalysts. Disinfection capability with the immobilised photocatalysts at 4.9 µE s−1 dm−3 was twice that of the slurry reactor. Survival ratios of less than 0.2 were obtained with a residence time of 50 min and an initial cell concentration of 10000 cfu cm−3 in the 6 dm3 plug-flow type reactor. © 2000 Society of Chemical Industry

Bioconversion of hydrogen sulfide to elementary sulfur by the photosynthetic bacterium Chlorobium thiosulfatophilum was studied in immobilized-cell and sulfur-settling free-cell recycle reactors. The cells immobilized in strontium alginate beads excreted elementary sulfur and accumulated it as crystal in the bead matrices, which made it possible that the reactor broth remained clear and the light penetrated the reactor deeper than with the free cells. In comparison with the free cells, the immobilized cells required 30% less light energy at a H2S removal rate of 2 mM/(L.h) and showed an activity of 2.4 times that of the free cells. However, in 40 h after the reaction the deterioration of the H2S removal efficiency became significant due to the accumulation of sulfur in the beads. The scanning electron micrograph (SEM) and energy-dispersive X-ray spectrometer (EDS) studies showed that the sulfur in the beads existed within a layer of 0.4 mm from the bead surface. In the sulfur-settling free-cell recycle reactor, about 80% of the sulfur excreted by the free cells could be removed in a settler. The 4-L fed batch reactor with the settler improved the light transmission to result in a H2S removal rate of 3 mumol/(mg of protein.h), 50% higher than that without it. The settling recycle reactor was much better in the removal of H2S than the immobilized-cell reactor because the former was a continuous system with the constant removal of sulfur particles by settling and of spent medium by supplying fresh medium at the same rate as the filtering rate of the reactor broth, while the latter was essentially a batch system where toxic metabolites and produced sulfur could not be removed.

Quantitative cytology was performed in nasal secretions of normal control (NC), seasonal allergic rhinitis in season (SAR), perennial allergic rhinitis (PAR), chronic sinusitis with mucoid secretion (MS), and chronic sinusitis with mucopurulent secretion (MPS). The majority of inflammatory cells were neutrophils in NC, MS, and MPS; the majority were eosinophils in SAR and PAR. The concomitant appearance of inflammatory cells in nasal secretions was found, i.e., there were significant correlations between neutrophil and eosinophil counts in MPS, and between eosinophil and basophil counts in SAR. The eosinophil/neutrophil ratio was more than 0.1 in SAR and PAR, but the ratio was less than 0.1 in all NC, all MPS, and in 93% of MS; this indicates that 0.1 in eosinophil/neutrophil ratio is the critical value between allergic and nonallergic nasal diseases.