The surface of titanium (Ti) dental implants was modified by applying a zinc (Zn)-doped titanium dioxide (TiO2) coating. Initially, the Ti surfaces were etched with NaOH, followed by a hydrolysis co-condensation using tetrabutyl titanate (TBT, Ti(OC4H9)4) and zinc nitrate hexahydrate (Zn(NO3)2 ‧ 6H2O), with ammonia water (NH3 ‧ H2O) acting as a hydroxide anion source. The morphology and chemical composition of the Zn-doped TiO2-coated Ti plates were characterized using X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS), Raman spectroscopy, and scanning electron microscopy (SEM). Synthesis temperatures were carefully adjusted to produce anatase Zn-doped TiO2 nanoparticles with a bipyramidal structure and approximate sizes of 100 nm. Wettability tests and cell viability assays demonstrated the biomedical potential of these modified surfaces, which showed high biocompatibility with a survival rate of over 95 % (p < 0.05) and improved wettability. Corrosion resistance tests using potentiodynamic polarization reveal that Zn-TiO2-treated samples with an anatase crystal structure exhibited a lower corrosion current density and more noble corrosion potential compared to samples coated with a rutile structure. This method offers a scalable approach that could be adapted by the biomaterial industry to improve the functionality and longevity of various biomedical implants.
Background: The forward head posture acts as a factor that can cause various neurovascular and musculoskeletal dysfunctions. But searching for a study on quality of life for patient with forward head posture was challenging. Therefore, this study aims to find the factors that most affect the quality of life in patients with forward head posture. Objectives: The purpose of this study was to investigate the correlations between the cranio-vertebral angle (CVA), neck disability index (NDI), pain, and sternocleidomastoid (SCM) thickness of patients with forward head posture and the quality of life of the patients and to figure out important factors that affect the quality of life of the patients with forward head posture. Design: Cress-sectional study. Methods: To measure the CVA, the angle at which the visible protrusion of C7 and the ear bead were connected was measured, and the neck disorder index was evaluated using the Korean version of NDI. The degree of pain of the subject was measured using a visual-analog scale (VAS). The SCM thickness was measured using an ultrasound imaging device, and the quality of life was evaluated using the Korean version of the World Health Organization quality of life questionnaire (WHOQL-BREF). Results: A significant predictive model showing 88% explanatory power for the dependent variable was confirmed, with an appropriate regression equation being found. The factor that most affected patients' quality of life in the forward head posture was confirmed by the SCM thickness. Conclusion: When applying an intervention to improve a patient's quality of life for patient with forward head posture, an intervention method that improves the SCM thickness should be recommended.
Emotional labor, characterized by a dysfunctional type of emotional regulation called surface acting, has detrimental psychological consequences on employees, including depression and social anxiety. Because such disorders exhibit psychological characteristics manifested through brain activation, previous studies have succeeded in distinguishing individuals with depression and social anxiety from healthy controls using their functional connectivity characteristics. However, it has not been established whether the functional connectivity characteristics associated with emotional labor are distinguishable. Thus, we obtained resting-state fMRI data from participants in the emotion labor (EL) group and control (CTRL) group, and we subjected their whole-brain functional connectivity matrices to a linear support vector machine classifier. Our analysis revealed that the EL and CTRL groups could be successfully distinguished on the basis of individuals' connectivity patterns, and confidence in the classification was correlated with the scores on the depression and social anxiety scales. These results are expected to provide insight on the neurobiological characteristics of emotional labor and enable the sorting of employees undergoing adverse emotional labor utilizing neurobiological observations.
Recently, elevator inspection and self-examination were strengthened through the revision of the Elevator Safety Management Act, but there have been no significant reduction in serious accidents and major failures. Therefore, the government intends to lay the foundation for reflecting the safety quality rating system, which adjusts the elevator inspection cycle, as a policy to induce safety management of preemptive and active management entities. This study systematically reviewed and classified the safety quality rating system for elevator inspection cycle adjustment in previous studies, collected expert opinions, and reconstructed the key items into realistic evaluation items, and evaluated and scored the relative importance of each factor through the AHP technique.
The objective of this experiment was to investigate the effect of drip irrigation volume on tomatoes (Solanum lycopersicum L.) grown in a greenhouse using perlite medium. Plants were treated by three different irrigation treatment I0, I25, and I50 (where irrigation volume of I25 and I50 was 25% and 50% higher than I0, having limited or no leaching). Growth characteristics of plants, yield and water use efficiency were measured. The result showed that plant height, leaf length and leaf width were lowest in the I0 treated plants. However, these parameters were not statistically significant differences between the plants that were grown in the I25 and I50 treatment. Soluble solids content, acidity and dry matter of 111th, 132nd, and 143rd days harvested tomato were higher in the plants irrigated with lowest volume (I0) than the higher volume (I25 or I50). In addition, water content was lower in the 111th and 132nd days of harvested tomatoes from the I0 treatment. The number of big-size tomatoes (>180 g) was significantly higher in the I25 irrigated plants. There was no significant difference in the total number of harvested fruits among the treatments. The average fruit weight and total yield of harvested tomatoes were lowest in the I0 treated plants. The water consumption of tomato was not significantly different amongst the treatments but water use efficiency was lowest in the I0 treatment. Principal component analysis revealed that total soluble solid and acidity of tomato showed a positive correlation between each other. These results suggest that I25 was the optimum irrigation treatment for tomato based on its measured growth characteristics, yield and water use efficiency.
According to the Nuclear Safety and Security Commission (NSSC) Notice No. 2021-26 “Delivery Regulations for the Low- and Intermediate Level Radioactive Waste (LILW)”, the activity of 3H, 14C, 55Fe, 58Co, 60Co, 59Ni, 63Ni, 90Sr, 94Nb, 99Tc, 129I, 137Cs, 144Ce, and gross alpha must be identified. Currently, the scaling factor of the dry active waste (DAW) for LILW is applied as an indirect evaluation method in Korea. The analyses are used the destructive methods and 55Fe, 60Co, 59Ni, 63Ni, 90Sr, 94Nb, 99Tc, and 137Cs, which are classified as nonvolatile nuclides, are separated through sequential separation and then measured by gamma detector, liquid scintillation counter (LSC), alpha/beta total counter (Gas Proportional Counter, GPC), and ICP-MS. We will introduce how to apply the existing nuclide separation method and improve the measurement method to supplement it.
The bilateral nuclear cooperation agreement provides the basis for technical and economic exchanges and research and development cooperation in the nuclear industry, while also having an important role in the peaceful use of nuclear power. The government of Republic of Korea has signed the supplementary and additional arrangements with the United States, Canada, and Australia to specify detailed procedures necessary for the implementation of the agreement. Currently, items under the bilateral nuclear cooperation agreement (i.e., obligated items) are managed through official documents and e-mails, and it is difficult for the government to systemically track item inventory and identify the person in charge. Another issue is the discrepancy of information between the annual report on obligated items and the report under the import and export procedure. In order to solve these problems, the government is establishing an import and export management system for obligated items to enhance transparency and national reliability in Korea. The ultimate purpose of this project is to not only faithfully fulfill the obligations under the bilateral nuclear cooperation agreement, but also to increase the efficiency of implementation work through systematization of databases and management of obligated items. In this paper, an improved management procedures are suggested by analyzing the required functions and problems. Also, this paper provides a conceptual design that can be applied to the management system for it obligated items by identifying and analyzing practical problems in the import and export management of mandatory items. As a result, key considerations and the conceptual design proposal for the ‘export and import management system for items subject to the nuclear bilateral cooperation agreement’ are derived. The result will be supplemented through continuous discussions with facility operators and the government to be utilized for detailed system design.
IAEA has the right and obligation to verify the states’ commitments for safeguards under the comprehensive safeguards agreement and additional protocols. There are IAEA inspections such as PIV, DIV, RII, SNRI under these agreements. As part of the implementation of this mission, the IAEA inspectors perform the verification for the state’s accounting reports related the nuclear materials such as ICR, PIL, MBR. To do well this verification, the inspectors often use non-destructive analysis, which aims to measure attributes of the items during the inspections. This kind of an activity aims to detect the missing nuclear items or wrong things in the facility using nuclear materials. In general, NDA techniques use the neutron counting and gamma ray spectrometry. Besides, IAEA also performs several verification measures as follows. - C/S (Containment and Surveillance techniques) is to maintain the continuity of the knowledge by giving assurance that its containment remains unimpaired. - Unattended and remote monitoring is to transmit the data from onsite of the facility through the on-line system. - E/S (Environmental Sampling) is to detect the minute traces of nuclear materials by smearing some points in the on-site of the facility. Nowadays, the above mentioned techniques are important ways to increase the effectiveness of the safeguards approaches reducing IAEA actual costs. To strengthen the effectiveness and improve the efficiency of safeguards approaches, IAEA always develops and adopts the techniques and equipment for safeguards. Especially, IAEA seems to be concerned with the improvement and development of the non-destructive techniques and equipment in the fields of nuclear fuel cycle. IAEA develops the new techniques and equipment through the help of MSSP (Member States Support Programs). The IAEA defines the needs of safeguards and coordinates the support programs. After the IAEA tests and evaluates the techniques/equipment developed, IAEA decides whether to use the developed techniques and equipment during the inspection by the procedure of the IAEA quality assurance. This paper aims at studying the current changes of the IAEA equipment such as DCVD, NGSS and HCES.
Accurate understanding of structural integrity and chemical reactivity of UO2 disposed in deep underground sites is of importance. Owing to the specific condition of the site location, UO2 may have substantially different properties from the conventional prediction. In this study, we demonstrate that the oxidation resistivity of UO2 is considerably modified by gadolinium (Gd), which is the element of neutron absorber and a byproduct of nuclear decay of radioactive U-235. Using density functional theory calculations, we investigate how the oxidation mechanism of UO2 changes with Gd incorporation in U lattice. Our study indicates that Gd remarkably enhances the thermodynamic stability of pristine UO2 against surface oxidation via three underlying mechanisms: (i) weakens the chemical bonding of adsorbed oxygen atom (O) with U, (ii) reduces active sites (U) for oxygen adsorption, and (iii) suppresses the subsurface diffusion of adsorbed O delaying the growth of the oxide layers on the UO2. Electronic and lattice structure analyses for Gd-doped UO2 indicate that amount of charge transfer from U to O is critically reduced and the lattice of the UO2 surface is contracted. Our results provide useful information for understanding long-term stability and improving the structural integrity of UO2 through the chemical doping process.
The success of machine learning approach to identify key correlation in large database is critically controlled by the reliability and accuracy of the data. Here, we demonstrate that rigorous material properties of radioactive nuclear fuels can be obtained by integrated approach of first principles calculations and the machine learning approach. The reliable database is established by density functional theory and molecular dynamics simulations, which is the input of the machine learning to analyze any correlation among the database. The outcomes are applied to evaluate thermodynamic, kinetic and electrochemical properties, which plays a key role for safe management of spent nuclear fuels.
The chelating agent and cellulose generated during the operating and decommissioning of a NPP’s form organic complexing compounds. That is accelerate the migration of radionuclide and have a bad influence of LILW disposal site. In this study, the GoldSim (RT module) program was used for the effects of radionuclide migration by organic complex compounds as described above. A scenario was derived for evaluation, and a conceptual design (Concept Art) of the GoldSim model was performed. 1) Derivation of the scenario. For the scenario, we selected a groundwater flow scenario in which groundwater flows in and radionuclides flow out after a lapse of time after the operation of the LILW disposal site in Gyeongju is closed. The inflowing groundwater comes into contact with radioactive waste and the radionuclides dissolve. The dissolved nuclides move past the drum and out of the disposal vessel due to the advection phenomenon. Radionuclides spilled from the disposal vessel pass through the silo internal filler (crushed stone) and reach the engineering barrier concrete. Radionuclides from degraded concrete are scenarios that move along the flow of groundwater to the near and far. 2) Radionuclide migration concept design. The radionuclide movement section was largely designed with Inner (Inside the silo), Near and Far. (A) Inner (Inside the silo) This section is where radionuclides move from the radiation source to the engineering barrier (silo). The detailed migration path was designed to allow radioactive nuclides to flow out and move to waste drums, solidified matrix of indrum, disposal vessel fillers, disposal vessels, silo fillers (crushed stones), and engineered barriers (concrete). The LILW disposal site in Gyeongju has a total of 6 silos. Each of the 6 silos was modeled and designed in consideration of the structural information and positional impact. (B) Near & Far. In generally design, the near is form source term to engineered barrier and far is beyond the engineered barrier. In this study, the near and far designed by radionuclide in the section from the beyond the engineering barrier (silo) to the sea through the groundwater flow through the natural rock. Especially in the case of near, the design was made by applying the position of the natural rock sampling drill hole.
소나무재선충은 소나무에이즈라고 불리는 소나무해충으로서 전국적으로 큰 피해를 끼치고 있다. 최근 소나무재선충 피해는 경북지역의 경주 및 포항지역에 많이 발생하고 있다. 특히 경주지역에는 역사적인 유적지 및 고분공원이 많은데 이 지역의 소나무 숲에 재선충 피해가 확산되고 있어서 역사적 가치뿐만 아니라 관광산업에 큰 피해가 예상된다. 재선충 피해를 줄이기 위하여 재선충 감염목에 대한 신속한 제거작업이 필요한데 이에 대한 진단이 어려운 실정이다. 본 연구에서는 LAMP-PCR 진단키트를 이용하여 경주 고적지 지역의 재선충 감염이 의심되는 소나무를 진단하였다. 경주남산 및 불국사부근 7개 지역에서 재선충 감염 의심목으로부터 시료를 채취하여 조사해 본 결과 약 50%의 소나무에서 양성반응을 나타내었다. 본 연구를 통하여 경주 고적지의 재선충 감염여부를 신속하게 진단할 수 있었고 경주 유적지의 재선충 피해를 억제하는데 기여할 수 있을 것으로 판단한다.