The public perspective on renewable energy versus nuclear power for carbon neutrality in South Korea.

South Korea has legislated "2050 carbon neutrality" in 2021 and is currently implementing it, and debate is brewing over which to focus on as the main means of achieving it in the power generation sector: renewable energy (RE) or nuclear power (NP). This article aims to collect and analyze data on the public preference for RE versus NP. In a national survey of 1000 people, respondents were first asked which was preferred, RE or NP, and then asked to indicate the preference intensity along a 5-point scale. Of all the respondents, 60.3% preferred RE and 27.7% preferred NP. The preference for the former was about 2.2 times more than that for the latter. However, the intensity of the preference for NP was 1.3 times more than that for RE. Both the two-limit Tobit model and ordered probit model have been applied to analyzing the factors influencing the preference. The effects of some variables on the preference for RE over NP are explained, and implications from this are discussed. The findings can be used as a reference to determine the main means of implementation of carbon neutrality or to increase the public acceptance of the specified means.

Vacuum-powered soft actuator with oblique air chambers for easy detachment of artificial dry adhesive by coupled contraction and twisting.

A gecko foot-inspired, mushroom-shaped artificial dry adhesive exploiting intermolecular forces between microstructure and surface has drawn research attention for its strong adhesive force. However, the high pull-off strength corresponding to the adhesive force matters when detaching fragile substrates. In this study, we report a vacuum-powered soft actuator having oblique air chambers and a dry adhesive. The soft actuator performs coupled contraction and twisting by applying negative pneumatic pressure inward and exhibits not only high pull-off strength but also easy detachment. This effective detachment can be achieved thanks to the twisting motion of the soft actuator. The detachment performances of the actuator models are assessed using a 6-degrees-of-freedom robot arm. Results show that the soft actuators exhibit remarkable pull-off strength decrement from ~20 N cm-2 to ~2 N cm-2 due to the twisting. Finally, to verify a feasible application of this study, we utilize the inherent compliance of the actuators and introduce a glass transfer system for which a glass substrate on a slope is gripped by the flexibility of the soft actuators and delivered to the destination without any fracture.

Economic benefits of preventing bird collisions in South Korea: findings from a choice experiment survey.

Bird deaths due to collisions with artificial structures, such as glass windows of buildings and transparent noise barriers, are continuing to occur in South Korea. The government is trying to prevent bird collisions by increasing the attachment of specially designed tapes to help birds avoid windows. This article estimates the economic benefits arising from the prevention of collisions by applying a choice experiment (CE). For this purpose, a CE survey of 1000 South Korean interviewees was conducted. The four attributes to be attached with the tapes for the CE application were a transparent soundproof wall window on an expressway, a transparent soundproof wall window on a general road, a glass window in a public building, and a glass window in a private building. The unit was the percentage of each structure with the tapes attached to the window. The marginal values of a one-unit (1%p) increase in each attribute were computed to be KRW 534 (USD 0.46), KRW 233 (USD 0.20), KRW 1,318 (USD 1.13), and KRW 12,930 (USD 11.05), respectively. This quantitative information will be an important reference for implementing the prevention policy. For example, based on the collision prevention of 1000 birds per structure, the priority for attaching tapes can be placed in the order of expressways, public buildings, private buildings, and general roads.

Public willingness to pay for eradicating a harmful marine organism: the case of Aurelia aurita in South Korea.

Aurelia aurita (AA), a legally registered harmful marine organism in South Korea, is damaging marine human leisure activities, local residents' tourism income, fisheries, and cooling water intake at power plants. The government is therefore seeking to eradicate AA by removing AA-attached larvae (polyps). This article looks into the public willingness to pay (WTP) for the eradication, utilizing a contingent valuation. For the sake of eliciting the WTP response, the one-and-one-half-bounded (OB) model was adopted. For comparison, the single-bounded (SB) model, which uses only the response to the first question in the OB model, was also applied. A spike model with a considerable plausibility that could explicitly deal with zero WTP responses was employed. Consequently, the estimation results of the SB model were used for further policy analysis. The household average WTP was estimated as KRW 3,911 (USD 3.49) per year, securing statistical significance. The national value was KRW 80.46 billion (USD 71.71 million) per annum. This figure can be interpreted as public value of the AA eradication project and used as essential basic data to evaluate the economic feasibility of implementing the project. Some factors such as income and education level significantly positively affected the intention of paying a suggested bid.

Monetary valuation of air quality improvement with the stated preference technique: A multi-pollutant perspective.

Air pollution is an important global issue, and governments are making efforts to reduce air pollutant emissions. The elaborate calculation of the social costs of air pollution is essential for justifying the substantial public expenditure on air pollution control policies. This study aims to derive the monetary value of reducing different kinds of air pollutants through the public's willingness to pay (WTP). A choice experiment survey is conducted to examine the public perception of air quality improvement, and the collected stated preference data are analysed with the hierarchical Bayesian logit model. The analysis results show that the public valuation of the emission reduction differs for individual pollutants. On average, the monetary value of one ton of emission reduction follows the order of PM2.5, PM10, SOx, TSP, NOx, and VOC. Based on the elicited WTP, the economic feasibility of the two air pollutant reduction plans of the South Korean Government is assessed. The benefit-to-cost ratio of the plans is 0.61 and 0.66, respectively, based on the mean WTP, indicating that they are not economically feasible at the moment. Implications for the efficient budget allocation of air pollution control policies are provided based on the results.

Environmental conservation value of an endangered species: the case of Cypripedium Japonicum.

The South Korean government is seeking information on the environmental conservation value (ECV) of Cypripedium japonicum, a plant on the first-level priority endangered species list of the Korea Ministry of Environment, as well as on the Red List of the International Union for Conservation of Nature. This research paper aims to assess the ECV by employing contingent valuation (CV) to elicit people's willingness to pay (WTP) for its conservation. To achieve this aim, in May 2020, a CV survey of 1,000 interviewees in South Korea was carried out employing a closed-ended question. The average household WTP is estimated to be KRW 3,770 (USD 3.07) per annum and secures statistical significance. From a national point of view, using information on the national population, this value comes to KRW 76.72 billion (USD 62.42 million) per year. Although the cost of conserving the species has not yet been accurately estimated, the ECV seems to be larger than the cost of conservation. Thus, it is socially desirable to conserve Cypripedium japonicum, and the conservation should be carried out in a stable and continuous manner.

Surface roughness and chemical composition changes of resin-modified glass ionomer immersed in 0.2% sodium fluoride solution.

BACKGROUND/PURPOSE: Glass ionomers undergo degradation when exposed to fluoride, which changes the physico-chemical characteristics of the materials. The purpose of this study was to evaluate the surface changes of resin-modified glass ionomer (RMGI) when immersed in a sodium fluoride (NaF) solution according to pH and time. MATERIALS AND METHODS: 120 RMGI specimens were prepared, and 30 specimens were placed in four types of storage solutions for four weeks; pH 7 artificial saliva with or without 0.2% NaF (As7 and NaF7), pH 5 artificial saliva with or without 0.2% NaF (As5 and NaF5). Interferometry and microscopy were performed to evaluate the surface roughness and topography, while spectroscopy was used to analyze the chemical composition changes. RESULTS: Rougher topography and increased roughness was exhibited in NaF groups, owing to the disintegration of the polysalt matrix. Reduced Sr and F was exhibited in all groups, whereas NaF group showed a decrease in Al and inorganic components. CONCLUSION: This study suggest that excessive use of fluoride therapy could lead to severe degradation of RMGI.

Public preference toward an energy transition policy: the case of South Korea.

South Korea is pursuing an energy transition policy (ETP) of expanding the use of renewable energy and natural gas and decreasing that of nuclear energy and coal in total generation. An investigation of whether the public is for or against the ETP is needed by the government. This article explores the public preference toward the ETP employing the data collected through a survey of 1000 individuals. They were asked to reveal their preference for the ETP on a five-point scale in the survey. Overall, there are more advocates of the ETP than those who opposed it. For the purpose of analyzing the determinants of advocacy and opposition of the ETP, an ordered probit model is employed. The results suggest that people living in the Seoul Metropolitan area think that the environment is more important than new jobs, or know the renewable energy 100% campaign before the survey is more favorable to the ETP than others. However, people who use electricity for heating tend to be negative about the ETP. As the age increases, people approve of the ETP, but when age goes beyond a certain level, they oppose it.

Deep Learning-Based Decision-Tree Classifier for COVID-19 Diagnosis From Chest X-ray Imaging.

The global pandemic of coronavirus disease 2019 (COVID-19) has resulted in an increased demand for testing, diagnosis, and treatment. Reverse transcription polymerase chain reaction (RT-PCR) is the definitive test for the diagnosis of COVID-19; however, chest X-ray radiography (CXR) is a fast, effective, and affordable test that identifies the possible COVID-19-related pneumonia. This study investigates the feasibility of using a deep learning-based decision-tree classifier for detecting COVID-19 from CXR images. The proposed classifier comprises three binary decision trees, each trained by a deep learning model with convolution neural network based on the PyTorch frame. The first decision tree classifies the CXR images as normal or abnormal. The second tree identifies the abnormal images that contain signs of tuberculosis, whereas the third does the same for COVID-19. The accuracies of the first and second decision trees are 98 and 80%, respectively, whereas the average accuracy of the third decision tree is 95%. The proposed deep learning-based decision-tree classifier may be used in pre-screening patients to conduct triage and fast-track decision making before RT-PCR results are available.

What do we know about public acceptance of designating marine protected area? The case of Jaran Bay in South Korea.

The South Korean Government is considering designating Jaran Bay, the habitat of the endangered marine species, Neophocaena asiaeorientalis, as a marine protected area. The Government needs information about public acceptance and the economic benefits of the designation. To unveil the information, this article aims to examine the public willingness to pay (WTP) using a contingent valuation based on a nationwide survey of 1000 households. As a WTP elicitation method, the one-and-one-half-bounded question format of asking an interviewee whether she/he has the intention of paying a presented bid through annual income tax was adopted. The WTP for the designation was statistically significantly estimated to be KRW 2665 (USD 2.27) per year per household. The estimate of the annual national value amounted to KRW 53 billion (USD 45.30 million). This value is by no means small, but it would take a huge amount of effort to elicit public consensus on the designation considering that a significant proportion of respondents (64.4%) revealed zero WTP.

Public perspectives on reducing the environmental impact of onshore wind farms: a discrete choice experiment in South Korea.

Onshore wind farms have the advantage of a lower cost than offshore wind farms, but their negative environmental impact has been pointed out as a problem. If this environmental impact can be lessened, public acceptance of onshore wind farms will be significantly increased. This study investigates public attitudes to the lessening of the environmental impact of onshore wind farms, focusing on three specific attributes: visual impact, ecosystem destruction and noise pollution. The area of empirical analysis is South Korea, and the choice experiment data are analysed using a mixed logit model to reflect the heterogeneity of the respondents' preferences. The analysis results show that there is considerable heterogeneity in respondents' preferences and that they regard the visual impact and the ecosystem destruction as more important than the noise pollution. Respondents are willing to pay KRW 197, KRW 138 and KRW 69 for a 1% improvement in visual impact, a 1% reduction in ecosystem destruction and a 1-dB reduction in noise, respectively. The results of the scenario analysis show that simultaneous improvements in the three attributes should be made in order to ensure a certain level of public acceptance. Related policy implications are provided based on the analysis results.

Study on the RBE estimation for carbon beam scanning irradiation using a solid-state microdosimeter.

PURPOSE: The purpose of this study was to study the field size effect on the estimated Relative Biological Effectiveness (RBE) for carbon scanning beam irradiation. METHODS: A silicon-on-insulator (SOI) microdosimeter system developed by the Centre for Medical Radiation Physics, University of Wollongong, Australia, was used for lineal-energy measurements (microdosimetric quantity). The RBE values were derived based on the modified microdosimetric kinetic model (MKM) at different depths in a water phantom in the scanning carbon beam for various scanned areas. RESULTS: Our study shows that the difference in RBE values derived from the SOI microdosimeter measurements with the MKM model and from the Treatment Planning System (TPS). The difference of the RBE values is within 6.5 % at the peak point of the spread-out Bragg Peak (SOBP) region. Compared to the spot-beam, RBE values obtained in the scanned-beam with a larger scanned area of 1.0 × 1.0 cm2 have better agreement with which estimated by the TPS. CONCLUSIONS: This study shows the possibility of using the SOI microdosimeter system as a quality assurance (QA) tool for RBE evaluation in carbon-pencil beam scanning radiotherapy.

How much value do people place on preserving the Seocheon coastal wetland in South Korea?

The ecosystem of the Seocheon coastal wetland (SCW), one of the wetland protected areas in South Korea, was registered in the Ramsar Wetlands in 2009 as an area rich in biodiversity and inhabited by endangered wild animals and plants. Since then, preserving the ecosystem of the SCW has emerged as an important task. Thus, the South Korean government is carrying out various research and management projects to preserve the ecological integrity of the SCW. This article aims to analyze public willingness to pay for preserving the SCW. For this purpose, 1000 households were surveyed, applying the contingent valuation (CV) method during September 2017. The respondents clearly understood the CV question and gave meaningful answers. The results show that an average value for the preservation was statistically significantly estimated to be KRW 2341 (USD 2.04) for all respondents. The national value expanded from the sample to the population is worth KRW 47.79 billion (USD 42.15 million) per year. Therefore, it can be seen that the public have sufficient acceptance for preserving the SCW.

Does combined heat and power mitigate CO2 emissions? A cross-country analysis.

Combined heat and power (CHP), which produces both heat and electricity at the same time, is so efficient that it can reduce energy use and emit less carbon dioxide (CO2) than conventional fossil fuel use. This article attempts to look empirically into the impact of CHP share in total electricity generation on CO2 emissions in a cross-country context. Data from 35 countries during the period 2009-2015 are used. For this purpose, the variable of CO2 emissions is regressed on three variables of constant, gross domestic product, and CHP share using two robust estimators. The results show that the level of CHP share of a country affects the level of its CO2 emissions negatively. That is, CHP leads to less CO2 emissions.

Assessing the external benefits of contaminated soil remediation in Korea: a choice experiment study.

Korean government has made and will continue to make a considerable investment in contaminated soil remediation to rectify the problems that arise from soil pollution. Quantitative information on the benefits of contaminated soil remediation is widely demanded by the public as well as the government. This article aims to assess the external benefits of contaminated soil remediation. A survey of 1000 randomly selected households was undertaken in Korea. The results show that the marginal willingness to pay values for a 1% decrease in human health hazard, a 1% improvement in biodiversity restoration, and 1000 new job creation by contaminated soil remediation are estimated to be KRW 204 (USD 0.17), 593 (0.50), and 238 (0.20) per household per year. The findings can provide policy-makers with useful information for both evaluating and planning the contaminated soil remediation.

Gold nanoparticles as a potent radiosensitizer in neutron therapy.

The purpose of this study was to investigate the potential of gold nanoparticles as radiosensitizer for use in neutron therapy against hepatocellular carcinoma. The hepatocellular carcinoma cells lines Huh7 and HepG2 were irradiated with γ and neutron radiation in the presence or absence of gold nanoparticles. Effects were evaluated by transmission electron microscopy, cell survival, cell cycle, DNA damage, migration, and invasiveness. Gold nanoparticles significantly enhanced the radiosensitivity of Huh7 and HepG2 cells to γ-rays by 1.41- and 1.16-fold, respectively, and by 1.80- and 1.35-fold to neutron radiation, which has high linear energy transfer. Accordingly, exposure to neutron radiation in the presence of gold nanoparticles induced cell cycle arrest, DNA damage, and cell death to a significantly higher extent, and suppressed cell migration and invasiveness more robustly. These effects are presumably due to the ability of gold nanoparticles to amplify the effective dose from neutron radiation more efficiently. The data suggest that gold nanoparticles may be clinically useful in combination therapy against hepatocellular carcinoma by enhancing the toxicity of radiation with high linear energy transfer.

Tumor treating fields inhibit glioblastoma cell migration, invasion and angiogenesis.

Treatment with alternating electric fields at an intermediate frequency (100-300 kHz), referred to as tumor treating fields (TTF) therapy, inhibits cancer cell proliferation. In the present study, we demonstrated that TTF application suppressed the metastatic potential of U87 and U373 glioblastoma cell lines via the NF-kB, MAPK and PI3K/AKT signaling pathways. Wound-healing and transwell assays showed that TTF suppressed cell migration and invasion compared with controls. Soft agar and three-dimensional culture assays showed that TTF inhibited both anchorage-dependent (cell proliferation) and anchorage-independent (colony formation) GBM cell growth. TTF dysregulated epithelial-to-mesenchymal transition-related genes, such as vimentin and E-cadherin, which partially accounted for TTF inhibition of cell migration and invasion. We further demonstrated that TTF application suppressed angiogenesis by downregulating VEGF, HIF1α and matrix metalloproteinases 2 and 9. TTF also inhibited NF-kB transcriptional activity. Collectively, our findings show that TTF represents a promising novel anti-invasion and anti-angiogenesis therapeutic strategy for use in GBM patients.

Biological effect of an alternating electric field on cell proliferation and synergistic antimitotic effect in combination with ionizing radiation.

Alternating electric fields at an intermediate frequency (100~300 kHz), referred to as tumour-treating fields (TTF), are believed to interrupt the process of mitosis via apoptosis and to act as an inhibitor of cell proliferation. Although the existence of an antimitotic effect of TTF is widely known, the proposed apoptotic mechanism of TTF on cell function and the efficacy of TTF are controversial issues among medical experts. To resolve these controversial issues, a better understanding of the underlying molecular mechanisms of TTF on cell function and the differences between the effects of TTF alone and in combination with other treatment techniques is essential. Here, we report experimental evidence of TTF-induced apoptosis and the synergistic antimitotic effect of TTF in combination with ionizing radiation (IR). For these experiments, two human Glioblastoma multiforme (GBM) cells (U373 and U87) were treated either with TTF alone or with TTF followed by ionizing radiation (IR). Cell apoptosis, DNA damage, and mitotic abnormalities were quantified after the application of TTF, and their percentages were markedly increased when TTF was combined with IR. Our experimental results also suggested that TTF combined with IR synergistically suppressed both cell migration and invasion, based on the inhibition of MMP-9 and vimentin.

Combination effects of tissue heterogeneity and geometric targeting error in stereotactic body radiotherapy for lung cancer using CyberKnife.

We have investigated the combined effect of tissue heterogeneity and its variation associated with geometric error in stereotactic body radiotherapy (SBRT) for lung cancer. The treatment plans for eight lung cancer patients were calculated using effective path length (EPL) correction and Monte Carlo (MC) algorithms, with both having the same beam configuration for each patient. These two kinds of plans for individual patients were then subsequently recalculated with adding systematic and random geometric errors. In the ordinary treatment plans calculated with no geometric offset, the EPL calculations, compared with the MC calculations, largely overestimated the doses to PTV by ~ 21%, whereas the overestimation were markedly lower in GTV by ~ 12% due to relatively higher density of GTV than of PTV. When recalculating the plans for individual patients with assigning the systematic and random geometric errors, no significant changes in the relative dose distribution, except for overall shift, were observed in the EPL calculations, whereas largely altered in the MC calculations with a consistent increase in dose to GTV. Considering the better accuracy of MC than EPL algorithms, the present results demonstrated the strong coupling of tissue heterogeneity and geometric error, thereby emphasizing the essential need for simultaneous correction for tissue heterogeneity and geometric targeting error in SBRT of lung cancer.

Comparison of Ocular Pulse Amplitude-Lowering Effects of Tafluprost and Latanoprost by Dynamic Contour Tonometry.

PURPOSE: A prospective study was performed to compare the ocular pulse amplitude (OPA)-lowering effects of tafluprost and latanoprost, used in the treatment of glaucoma, using dynamic contour tonometry. METHODS: The study population consisted of patients with normal-tension glaucoma (NTG) (n = 27) or primary open-angle glaucoma (POAG) (n = 14) treated with tafluprost and latanoprost. All patients were newly diagnosed with NTG and POAG and had undergone no previous treatment. Intraocular pressure (IOP) was measured by Goldmann applanation tonometry (GAT), OPA was measured by dynamic contour tonometry, and corrected OPA (cOPA) was calculated before and after 1 week, 1-3 months of treatment. RESULTS: Initial IOP and OPA were 17.12 ± 3.75, 2.30 ± 0.56 mmHg and 17.53 ± 2.87, 2.65 ± 0.94 mmHg in the tafluprost and latanoprost groups, respectively. After 3 months of treatment, IOP and OPA were 13.00 ± 2.04 mmHg (24.1%) and 1.51 ± 0.30 mmHg (34.3%), respectively, in the tafluprost group. These values were 15.40 ± 2.32 mmHg (12.2%) and 2.08 ± 0.83 mmHg (21.5%), respectively, in the latanoprost group. Therefore, tafluprost significantly reduced IOP (P = 0.01), but OPA-lowering effects did not differ significantly between the 2 groups (P = 0.17). However, the cOPA-lowering effect of tafluprost (1.27 mmHg, 55.2%) was significantly greater than that of latanoprost (0.84 mmHg, 31.7%) after 3 months of treatment (P < 0.001). CONCLUSIONS: Tafluprost and latanoprost, used to treat glaucoma, have marked OPA-lowering effects as well as IOP-lowering effects. Moreover, tafluprost has a greater effect than latanoprost. Therefore, it can be used for patients in need of IOP reduction and at risk of glaucoma progression.