• Computers and Concrete
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• v.23 no.3
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• pp.189-201
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• 2019

Recent advances in the concrete technology are aiding in minimizing the use of conventional materials by substituting by-products of various industries and energy sources. A large amount of stone waste i.e., dust and slurry form both are being originated during natural stone processing and causing deadily effects on the environment. The disposal problem of stone waste can be resolved effectively by using waste in construction industries. In present work, Kota stone slurry powder, as a substitution of cement was used along with accelerators namely calcium nitrate and triethanolamine as additives, to study their impact on various properties of the concrete mixtures. Kota stone slurry powder (7.5%), calcium nitrate (1%) and triethanolamine (0.05%) were used separately as well in combination in different concrete mixtures. Mechanical Strength, modulus of elasticity and electrical resistivity of concrete specimens of different mix proportions under water curing were studied experimentally. The durability properties in terms of strength and electrical resistivity against sulphate and chloride solution attack at various curing ages were also studied experimentally. Results showed that accelerators and Kota stone slurry powder separately enhanced the mechanical strength and electrical resistivity; but, their combination decreased strength at all curing ages. The durability of concrete specimens was also affected under the exposure to chemical attack too. Kota stone slurry powder found to be the most effective material among all materials. Material characterization was also done to study the microstructural properties.

• Environmental Engineering Research
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• v.23 no.4
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• pp.354-363
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• 2018

We examined the levels of brominated flame-retardants (BFRs) including polybrominateddiphenyl ethers (PBDEs), tetrabromobisphenol-A (TBBPA), hexabromocyclododecane (HBCD), and phthalates in indoor dusts in residential houses in Korea, and their distribution patterns depending on building characteristics. Mean concentrations of phthalate esters ($1,825{\mu}g\;g^{-1}$) were significantly higher than that of BFRs (PBDE: $1,332ng\;g^{-1}$, HBCDs: $459ng\;g^{-1}$, and TBBPA: $213ng\;g^{-1}$), indicating more frequent use of phthalate-containing products such as PVC flooring in the Korean houses. PVC flooring house was associated with higher concentrations of DEHP (p = 0.001) and BBP (p = 0.012), indicating that exposure to phthalate was higher in the PVC flooring house. Building age was significantly related with levels of PBDEs especially BDE-47 (p = 0.062), BDE-203 (p = 0.007), DEHP (p = 0.004), and BBP (p = 0.070), respectively, indicating that older buildings can produce higher amounts of PBDEs and phthalates. Our study can provide important information on the sources of BFRs and phthalates in residential houses in Korea.

• 대한예방의학회:학술대회논문집
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• 1994.02a
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• pp.405-411
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• 1994

Hazardous wastes released into the general environment are of concern to the public and to public health authorities. In response to this concern, the Comprehensive Environmental Response, Compensation, and Liability Act, as amended (commonly called Superfund), was enacted in 1980 to provide a framework for environmental, public health, and legal actions concerning uncontrolled releases of hazardous substances. The Agency for Toxic Substances and Disease Registry (ATSDR) was created by Superfund to address the public health issues of hazardous wastes in the community environment. Two key Agency programs, Public Health Assessments and Toxicological Profiles, are designed to assess the risk to human health of exposures to hazardous substances that migrate from waste sites or through emergency releases (e.g., chemical spills). The Agency's public health assessment is a structured process that permits ATSDR to identify which waste sites or other point sources require traditional public health actions (e.g.. human exposure studies, health studies, registries, health surveillance, health advisories). The ATSDR qualitative public health assessment complements the U.S. Environmental Protection Agency's quantitative risk assessment. For Superfund purposes, both assessments are sitespecific. ATSDR's toxicological profiles are prepared for priority hazardous substances found most frequently at Superfund sites. Each profile presents the current toxicologic and human health effects information about the substance being profiled. Each profile also contains Minimal Risk Levels (MRLs), a type of risk assessment value. This paper covers ATSDR's experience in conducting public health assessments and developing MRLs, and it relates this experience to recommendations on how to improve chemical risk assessments.

• Pediatric Infection and Vaccine
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• v.30 no.3
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• pp.141-151
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• 2023

Purpose: Intestinal parasitic infections (IPIs) are a major health problem worldwide, especially in developing countries. According to the literature, children are more likely to get infected due to more frequent exposure to sources of infection. Methods: In this study, we collected 500 fecal samples from children under 15 years of age who referred to labs in Ilam city. All samples were microscopically examined using formalin-ether concentration and Trichrome staining techniques. The results were analyzed using SPSS 20.0. Results: Among 500 investigated samples, 4 types of parasites were detected. Giardia lamblia, Entameba coli, and Blastocystis hominis were identified as intestinal protozoa, and pinworm as intestinal worm. In this study, 23 cases (4.6%) had parasitic infections. 13 patients (2.6%) were infected with Giardia parasite, 4 patients (0.8%) with E. coli, 3 patients (0.6%) with B. hominis and 3 patients (0.6%) had pinworms. Conclusions: The findings of this study showed that the prevalence of IPIs among children aged under 15 years in Ilam is relatively down, which can be attributed of sufficient information of parents and children about the modes of parasite transmission and the important role of carriers in the pathogen cycle.

• Nuclear Engineering and Technology
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• v.56 no.6
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• pp.2428-2435
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• 2024

Training for radiation protection and control requires a visual understanding of radiation, which cannot be perceived by the human senses. Trainees must also master the effective use of measuring instruments. Traditionally, such training has exposed trainees to radiation sources. Here, we present a novel e-training strategy that enables safe, exposure-free handling of a radiation measuring tool called a survey meter. Our mixed reality radiation-training system merges the physical world with a digital one. Collaborating with a mixed reality headset (HoloLens 2), this system constructs a mock-up of a survey meter in real-world space. The HoloLens 2 employs a browser-based application to visualize radiation and to simulate/share the use of the survey meter, including its physical movements. To provide a dynamic learning experience, the system adjusts the survey-meter mock-up readings according to the operator's movements, distance from the radiation source, the response time of survey meter, and shielding levels. Through this approach, we expect that trainees will acquire practical skills in interpreting survey-meter readings and gain a visual understanding of radiation in real-world situations.

• Nuclear Engineering and Technology
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• v.56 no.10
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• pp.4375-4383
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• 2024

In this study, we first produced the Korean-specific dose coefficients (DCs) for soil contamination using the Mesh-type Reference Korean Phantoms (MRKPs). The Korean DCs were compared with the values in ICRP Publication 144 produced using the Caucasian-based ICRP reference phantoms to investigate dosimetric impact due to the racial difference (Korean/Asian vs Caucasian). Monte Carlo dose calculations using the Geant4 code were conducted where the photon and electron sources in the phase-space data used for the ICRP-144 DC calculations were irradiated to the MRKPs. For photons, the organ DCs of the MRKPs showed a good agreement with the ICRP-144 DCs (deviations <20 %) for most energies, while significant differences at energies below 0.05 MeV were observed by up to a factor of 55.6 (thymus at 0.015 MeV). For electrons, notable differences in the organ DCs were observed the overall energy region (deviations >20 % for most cases). The effective DCs of the MRKPs showed an excellent agreement with the ICRP-144 DCs for photons (deviations <16 %), whereas notable differences by up to 1.7 times (0.05 MeV) were observed for electrons. The Korean DCs for soil contamination will be beneficially used in dose estimates for Koreans especially in risk assessments.

• Journal of Environmental Policy
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• v.7 no.2
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• pp.67-90
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• 2008

The purpose of this study is to develop indoor air quality management strategies regarding indoor air pollutants while considering various factors affecting indoor pollutants concentration. The Integrated Indoor Air Quality model(IIAQ) developed by Seoul National University is used for this study. The IIAQ model is a tool that can provide an integrated view to indoor environmental pollution by simulating suggested scenarios. The results of the modeling are used to assess health risk. The concentrations that are used for the risk characterization are weighted concentrations based on the period of time in each place and existing Indoor Air Quality(IAQ) standards. The estimated concentration of toluene and formaldehyde for 10 years through the IIAQ model was 207.3 $ug/m^3$ and 36.4 $ug/m^3$ in indoors, and 55.9 $ug/m^3$ and 8.62 $ug/m^3$ in outdoors. These concentrations are lower than the existing IAQ standards. The estimated carcinogenic risk of formaldehyde is up to 1.05E-03 for the adult male group and exceeds 1E-06 for all receptor groups. This value means that cancer could affect one person out of 1000. The estimated non-carcinogenic risk of toluene was lower than 1, which means that there was no serious non- carcinogenic risk. The result of modeling shows that using low emitting indoor sources is the most effective strategy for both formaldehyde and toluene. This risk assessment suggests that the total exposure levels of existing IAQ standards may cause serious carcinogenic risk. In order to avoid uncontrolled risk, it is suggested that the current IAQ standards should be adjusted by taking into account the total amount of exposure from all exposure pathways from indoor and outdoor sources.

• Journal of radiological science and technology
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• v.39 no.3
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• pp.421-427
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• 2016

We aim to offer basic materials about infection management through conducting bacterial contamination test about general radiography equipment and CT equipment installed in ER of three general hospitals with 100 sickbeds or more located in Gyeongsangbuk-do Province, and suggest management plan. It had been conducted from 1st December 2015 to 31st December, and objects were general radiography equipment and CT equipment of emergency room located in Gyeongsangbuk-do Province. For general radiography equipment, sources were collected from 4 places such as upper side of control box which employees use most, upper side of exposure button, whole upper side of table which is touching part of patient's skin, upper side of stand bucky's grid, and where patients put their jaws on. For CT equipment, sources were collected from 3 places such as upper side of control box which radiography room employees use most, X-ray exposure button, whole upper side of table which is touching part of patient's skin, and gantry inner. Surface contamination strain found at general radiography equipment in emergency room of radiology are Providencia stuartii(25%), Stenotrophomonas maltophilia(18%), Enterobacter cloacae(8%), Pseudomonas species(8%), Staphylococcus epidermidis(8%), Gram negative bacilli(8%), and ungrown bacteria at incubator after 48 hours of incubation (67%) which is the biggest. Most bacteria were found at upper side of stand bucky-grid and stand bucky of radiology's general radiography equipment, and most sources of CT equipment were focused at patient table, which means it is contaminated by patients who have various diseases, and patients who have strains with decreased immunity may get severe diseases. Thus infection prevention should be made through 70% alcohol disinfection at both before test and after test.

• Journal of Preventive Medicine and Public Health
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• v.27 no.4 s.48
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• pp.711-734
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• 1994

Among chemical agents in herbicides, dioxin (2, 3, 7, 8-tetrachloro dibenzo-$\rho$-dioxin : TCDD), a chemical contaminant in herbicides sprayed during the Vietnam War has been known to be the major agent causing toxic effects. Approximately 320,000 korean soldiers participated the Vietnam War from 1964 to 1974. Although the potential hazards of the herbicides among Korean veterans exposed were implicated, the problem had not been a public issue until 1991 when Korean veterans were informed U.S. companies, the herbicides manufacturer payed fund, from which a trust fund for New Zealand and Australian Class members were established in 1985. After a series of appeals and demonstration by the Korean Veterans demanding medical care and compensation for their serious health damages, a bill of medical care and compensation for herbicides victims was promulgated in March 1993 and become effective from May 1993, This study was carried out with two major objectives : the first to understand the health problems caused from the herbicides by reviewing literatures published, and the second to examine the nature and extent of health impacts among Korean veterans exposed and to develop valid study methods for the major study by interviewing and reviewing records on a part of veterans (638 persons) registered and completed medical examination in Seoul Veterans Administration Hospital from June to October 1993. The results obtained are as followings: 1. The literature review of 107 papers revealed that 1) Dioxin is teratogenic, carcinogenic and affects almost all organs including nervous, endocrine, and reproductive systems in animal experiments. 2) The diseases showing evidence of causal association were Hodgkin's disease, non-Hodgkin's disease, lung cancer, lymphoma, soft tissue sarcoma, chloroacne and polyneuropathy when judged on the basis of consistency in study results and biological plausibility. 2. Interview and medical record review study on 638 veterans, though limited validity owing to lack of control group, crude estimates of dioxin exposure levels (no biomarkers measurable), and uncertainty of diagnosis, showed that: 1) Most of the study subject's were in their 40's of age and had been dispatched to Vietnam during the period from $1965{\sim}1970$ around one year. 2) Most frequently complained symptoms in medical examination were motor weakness (32%), sensory abnormalities in extremities (23%), skin diseases (22%), and pain in extremities (20%) whereas in Interview they were more frequent in order of skin problem (44%), motor weakness (38%), sensory abnormalities and pain in extremities(17% and 19% each). Kappa indices on the same category of complaints between two sources of information were variable and relatively low. 3) On medical examination, only a part of the 638 subjects had initial impression (442 pts) and final diagnosis (218 pts) suggesting decision making on diagnosis appeared to be difficult even with all available modern medical technologies: in initial impression disorders from peripheral and central neuropathy were predominant whereas in final diagnosis various types of skin disorder were most frequent 4) When dose-response relationship between several conditions (from questionnaire) and arbitrary exposure scores were examined by CMH linear trend test, spontaneous abortion, sexual problems and health problem of offsprings showed statistically significant linear trends. However, pregnancy, accident and suicidal attempts did not show any relationship in this study capacity. 5) Among complaints, psychosis and neurosis (anxiety, phobia) in interview study, and memory disorder and psychosis in medical record study revealed linear trend. 6) Skin disorder was the only condition showing linear trend in initial impression and none in final diagnosis on medical examination. Even though objective to select out dioxin-related disease or group of diseases from this study was not achieved the research experiences provided firm basis for developing various methodological approaches. 3. From this preliminary study we concluded that a larger scale major epidemiologic study on health impacts of herbicides among Korean veterans exposed is not only Indispensible but also well designed study with more valid exposure information and diagnosis may be able to establish causal relationship between certain groups of diseases and exposure to the herbicides among Korean veterans.

• Journal of Radiation Protection and Research
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• v.37 no.4
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• pp.219-225
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• 2012

This study makes differentiated regulations which can maximize the efficiency and convenience of radiation safety regulations by deriving evidence required to establish reasonable safety regulatory structure based on the determination of the levels of actual radiation safety regulations for radiation safety managers to perform radiation safety. We surveyed approximately 10% of radiation safety managers from domestic radiation-using organizations which was based on the Nuclear Safety Act and NUREG Vol. 1~21 of RS-G-1.9 (2005), NRC of IAEA, etc. The radiation safety managers showed the highest level of awareness on the requirements for exposure management ($3.32{\pm}0.910$), and the lowest level on the requirements for record keeping and storage of documents ($2.84{\pm}0.826$). Industrial organizations showed higher levels of awareness than medical organizations whose regulations should be more stringent on requirements of the status and management of radioactive sources, facilities, measurements, pollution control, measuring equipment, monitoring, education and training, and exposure management. This suggests that the actual regulations need to be re-evaluated because it is attributed to the regulations which are statistically significant difference of the levels of radiation safety regulations between industrial organizations and medical organizations. The process of developing regulatory requirements for each characteristic of domestic organizations needs to be done in future studies, as well as safety regulations to maximize convenience should be achieved if radiation safety regulations are conducted in consideration with the characteristics of each organization.