Se sorption onto Ca-type montmorillonite purified from Bentonil-WRK—a new research bentonite introduced by Korea Atomic Energy Research Institute—was examined under ambient conditions (pH 4−9, pe 7−9, I = 0.01 M CaCl2, and T = 25°C). Se(IV) was identified as the oxidation state responsible for weak sorption (Kd < 22 L∙kg−1) by forming surface complexes with edge functional groups of the montmorillonite. Thermodynamic modeling, considering reaction mechanisms of outer-sphere complexation (≡AlOH2 + + HSeO3 − ⇌ ≡AlOH3SeO3, log K = 0.50 ± 0.21), inner-sphere complexation (2≡AlOH + H2SeO3(aq) ⇌ (≡Al)2SeO3 + 2H2O(l), log K = 7.89 ± 0.51), and Ca2+-involved ternary complexation (≡AlOH + Ca2+ + SeO3 2− ⇌ ≡AlOHCaSeO3, log K = 7.69 ± 0.28) between selenite and aluminol sites of montmorillonite, acceptably reproduced the batch sorption data. Outer- and inner-sphere complexes are predominant Se(IV) forms sorbed in acidic (pH ≈ 4) and near-acidic (pH ≈ 6) regions, respectively, whereas ternary complexation accounts for Se(IV) sorption at neutral pHs under the ambient conditions. The experimental and modeling data generally extend a material-specific sorption database of Bentonil-WRK, which is essential for assessing its radionuclide retention performance as a buffer candidate of deep geological disposal system for high-level radioactive waste.

Technetium has been identified as an element of interest for the safety assessment of a deep geological repository for used nuclear fuel. In this study, the sorption of Tc(IV) onto MX-80 bentonite, illite, and shale in ionic strength (I) 0.1–6 mol·kgw−1 (m) Na-Ca-Cl solutions at pHm = 4–9 and limestone at pHm = 5–9 was studied. Tc(IV) sorption on MX-80 increased with pHm from 4 to 6, reached the maximum at pHm = 6–7, and then gradually decreased with pHm from 7 to 9. Tc(IV) sorption on illite gradually increased with pHm from 4 to 7, and then decreased as pHm increased. The sorption properties of Tc(IV) on shale were quite similar to those on illite. Tc(IV) sorption on limestone slightly increased with pHm from 5 to 6 and then seemed to be constant at pHm = 6–9. Tc(IV) sorption on all four solids was independent of ionic strength (0.1–6 m). The 2 site protolysis non-electrostatic surface complexation and cation exchange model successfully simulated the sorption of Tc(IV) onto MX-80 and illite and the optimized values of surface complexation constants were estimated.

Technetium-99 is identified as an element of interest for the safety assessment of a deep geological repository for used nuclear fuel. The sorption behavior of Tc(IV) onto MX-80 and granite in Ca-Na-Cl solutions of varying ionic strength (0.05–1 mol·kgw−1 (m)) and across a pHm range of 4–9 was studied in this paper. Sorption of Tc(IV) was found to be independent of ionic strength in the range of 0.05 to 1 m for both MX-80 and granite. Sorption of Tc(IV) on MX-80 increased with pHm from 4 to 7 and then decreased with pHm from 8 to 9. Sorption of Tc(IV) on granite gradually increased with pHm from 4 to 8 and then became almost constant or slightly decreased with pHm from 8 to 9. A 2 site protolysis non-electrostatic surface complexation and cation exchange sorption model successfully simulated sorption of Tc(IV) on MX-80 and granite. Optimized values of surface complexation constants (log K0) are proposed.

본 연구는 인도의 전통의학인 아유르베다와 중국의 중의학 사이의 유사점과 차이점을 통해 아유르베다의 다섯 원소아 ( 까샤, 바유, 떼자스, 아빠스, 쁘리띠위)와 중의학의 오행(수, 화, 목, 금, 토)의 개념을 중심으로 두 의학 체계의 기본 구조 와 생명력에 대한 이해를 돕고자 한다. 아유르베다에서는 세 가지 도샤와 일곱 가지 기본 조직(다뚜)을 통해 신체의 기능 과 질병을 설명하는 반면, 중의학은 다섯 원소와 장부의 상 호 작용을 중심으로 신체와 질병을 파악하였다. 두 체계 모 두 생명력 에너지와 신체의 다양한 조직 및 장기와의 관계를 중요시하며, 질병의 원인과 치료에 대한 접근 방식에서 유사 성이 있으며, 특히, 소화의 중요성과 감정 및 에너지 흐름과 의 관계를 중요시한다. 문화적 기후적 지리적 차이에서 오는 두 이론의 성립에 대한 차이로 인해 각기 다른 의학의 형태 를 가지고 있지만, 본질적인 면인 인간의 신체와 마음을 이 해하는데 유사한 방식을 사용함을 보여주며, 두 전통 의학 체계에 대한 깊은 이해와 추가 연구를 위한 기반을 제공한다.

Composite-based piezoelectric devices are extensively studied to develop sustainable power supply and selfpowered devices owing to their excellent mechanical durability and output performance. In this study, we design a leadfree piezoelectric nanocomposite utilizing (Ba0.85Ca0.15)(Ti0.9Zr0.1)O3 (BCTZ) nanomaterials for realizing highly flexible energy harvesters. To improve the output performance of the devices, we incorporate porous BCTZ nanowires (NWs) into the nanoparticle (NP)-based piezoelectric nanocomposite. BCTZ NPs and NWs are synthesized through the solidstate reaction and sol-gel-based electrospinning, respectively; subsequently, they are dispersed inside a polyimide matrix. The output performance of the energy harvesters is measured using an optimized measurement system during repetitive mechanical deformation by varying the composition of the NPs and NWs. A nanocomposite-based energy harvester with 4:1 weight ratio generates the maximum open-circuit voltage and short-circuit current of 0.83 V and 0.28 A, respectively. In this study, self-powered devices are constructed with enhanced output performance by using piezoelectric energy harvesting for application in flexible and wearable devices.

In this investigation, samples of the chemical (Hg1-xPbxBa2Ca1.8Mg0.2Cu3O8+δ) were prepared utilizing a solid-state reaction technique with a range of lead concentrations (x = 0.0, 0.05, 0.10, and 0.20). Specimens were pressed at 8 tons per square centimeter and then prepared at 1,138 K in the furnace. The crystalline structure and surface topography of all samples were examined using X-ray diffraction (XRD) and atomic force microscopy (AFM). X-ray diffraction results showed that all of the prepared samples had a tetragonal crystal structure. Also, the results showed that when lead was partially replaced with mercury, an increase in the lead value impacted the phase ratio, and lattice parameter values. The AFM results likewise showed excellent crystalline consistency and remarkable homogeneity during processing. The electrical resistivity was calculated as a function of temperature, and the results showed that all samples had a contagious behavior, as the resistivity decreased with decreasing temperature. The critical temperature was calculated and found to change, from 102, 96, 107, and 119 K, when increasing the lead values in the samples from 0.0 to 0.05, 0.10, and 0.20, respectively.

Thermodynamic sorption modeling can enhance confidence in assessing and demonstrating the radionuclide sorption phenomena onto various mineral adsorbents. In this work, Ca-montmorillonite was successfully purified from Bentonil-WRK bentonite by performing the sequential physical and chemical treatments, and its geochemical properties were characterized using X-ray diffraction, Brunauer-Emmett-Teller analysis, cesium-saturation method, and controlled continuous acidbase titration. Further, batch experiments were conducted to evaluate the adsorption properties of Cs(I) and Sr(II) onto the homoionic Ca-montmorillonite under ambient conditions, and the diffuse double layer model-based inverse analysis of sorption data was performed to establish the relevant surface reaction models and obtain corresponding thermodynamic constants. Two types of surface reactions were identified as responsible for the sorption of Cs(I) and Sr(II) onto Ca-montmorillonite: cation exchange at interlayer site and complexation with edge silanol functionality. The thermodynamic sorption modeling provides acceptable representations of the experimental data, and the species distributions calculated using the resulting reaction constants accounts for the predominance of cation exchange mechanism of Cs(I) and Sr(II) under the ambient aqueous conditions. The surface complexation of cationic fission products with silanol group slightly facilitates their sorption at pH > 8.

The permanent disposal of discharged spent nuclear fuel (SNF) and contaminated radioactive waste generated from the subsequent chemical treatments of SNF has become a serious pending issue in many countries that operate the nuclear power plants. Among the diverse engineering solutions proposed for the disposal of high-level radioactive waste (HLW), deep geological disposal (DGD) has been considered as the most proven and safe option to prevent any significant release of radionuclides into the biosphere and to predictably ensure the long-term performance of disposal system. The DGD system consists of multiple structural components; the bentonite clay-based buffer and tunnel backfills are designed to perform the primary hydrogeochemical functions of 1) inhibiting the ingress of groundwater and reactive substances that could compromise the integrity of canister and 2) retarding the migration of released radionuclides into biosphere by providing the sufficient chemisorption sites. Montmorillonite, which is a 2:1 phyllosilicate mineral belonging to smectite group, constitutes the majority of bentonite, and it mainly predominate the swelling and chemisorption capacities of the clay material. Thus, it is essentially required to thoroughly understand the chemical interactions of major radionuclides and other important substances with montmorillonite in advance to accurately evaluate the long-term retention performance of engineered barriers and to reduce the uncertainties in the safety assessment of a deep geological repository (DGR) ultimately. Thus far, sorption of dissolved species onto mineral adsorbents has been generally described and quantified using the simple sorption-desorption distribution coefficient (Kd) concept; since any specific reaction mechanisms are not considered and reflected in the Kd concept, an empirical Kd value is intrinsically dependent on the aqueous conditions under which it was measured. In this framework, substantial scientific efforts have been made to develop a robust basis for geochemically parametrizing the sorption phenomena more reliably, and the application of thermodynamic sorption modeling (TSM), which is based on the chemical principle of mass action laws, has been studied with the aim of improving overall confidence in the description of radionuclide migration under a wide range of aquatic conditions. The disposal performance demonstration R&D division of KAERI introduced a new reference Ca-bentonite clay called Bentonil-WRK (Clariant Korea) for HLW disposal research in 2021 as the domestic Ca-bentonite sources have being depleted. We successfully separated and purified Ca-montmorillonite from the Bentonil-WRK clay, and its geochemical characteristics were meticulously studied by means of XRD, BET, CEC, FT-IR analyses and controlled acid-base titration. In this work, chemical sorption behaviors of aqueous iodide and benzoate, which are a major fission product in HLW and a model ligand of complex natural organic matters present in the deep geological environment, onto the purified Camontmorillonite were assessed under ambient conditions of S/L = 5 g/L, I = 0.01 M CaCl2, pH = 4- 9, pCO2 = 10-3.4 atm, and T = 25°C. Further, their unique adsorption envelopes and corresponding thermodynamic reaction constants refined from the diffuse double layer model (DDLM)-based inverse modeling of experimental sorption data were discussed.

Buffer materials play an important role in preventing the leakage of radionuclides from the residue. The mineralogical properties of these buffer materials are critical in repository design. This study presents the fundamental properties of Na-type MX80 and a novel Ca-type Bentonil- WRK. The CaO to MgO ratio in Bentonil-WRK was approximately 1:1, and the CaO to Na2O ratio was approximately 2.8:1. These results suggest that Bentonil-WRK demonstrates a lower swelling index compared to Gyeongju bentonite due to its CaO-to-MgO ratio’s proximity to 1:1, despite having a higher montmorillonite content than Gyeongju bentonite. The results of this research can provide useful foundational data for the evaluation of the thermal-hydraulic-mechanical-chemical behavior of buffer materials.

Graphene-based sensors have emerged as significant tools for biosensing applications due to their unique electrical, mechanical, and thermal properties. In this study, we have developed an innovative and sensitive aptasensor based on the surfacemodified graphene for the detection of lung cancer biomarker CA125. The sensor leverages the combination of graphene surface and gold nanoparticles (AuNPs) electrodeposition to achieve a high level of sensitivity and selectivity for the biomarker detection. A noticeable decrease in electron transfer resistance was observed upon the AuNPs deposition, demonstrating the enhancement of electrochemical performance. Our experimental findings showed a strong linear relationship between the sensor response and CA125 concentrations, ranging from 0.2 to 15.0 ng/mL, with a detection limit of 0.085 ng/ mL. This study presents a novel approach to lung cancer detection, surpassing the traditional methods in terms of invasiveness, cost, and accuracy. The results from this work could pave the way for the development of graphene-based sensors in various other biosensing applications.

This study evaluated a potential sterilization process that uses calcium hypochlorite (Ca(ClO)2) as a disinfectant and hydrogen peroxide (H2O2) as a neutralizing agent for monoculture processes of microalgae (Nannochloropsis oculata). The results showed that no contaminants (prokaryote) were present when the Ca(ClO)2 concentration was greater than 0.010%. The use of an equivalent amount of H2O2 completely neutralized Ca(ClO)2 and had an additional bactericidal effect because of the formation of singlet oxygen. No substantial difference was observed in the biomass accumulation and chlorophyll contents compared to those in cultures sterilized using conventional physical methods such as autoclaving. Therefore, chemical sterilization using Ca(ClO)2 and H2O2 has an excellent economic advantage, and we expect the proposed ecofriendly chemical sterilization method to become a critical culture technology for microalgae-related industrialization.

In this study we examine variations in the structure of perovskite compounds of LaBa2Cu2O9, LaBa2CaCu3O12 and LaBa2Ca2Cu5O15 synthesized using the solid state reaction method. The samples’ compositions were assessed using X-ray fluorescence (XRF) analysis. The La: Ba: Ca: Cu ratios for samples LaBa2Cu2O9, LaBa2CaCu3O12 and LaBa2Ca2Cu5O15 were found by XRF analysis to be around 1:2:0:2, 1:2:1:3, and 1:2:2:5, respectively. The samples’ well-known structures were then analyzed using X-ray diffraction. The three samples largely consist of phases 1202, 1213, and 1225, with a trace quantity of an unknown secondary phase, based on the intensities and locations of the diffraction peaks. According to the measured parameters a, b, and c, every sample has a tetragonal symmetry structure. Each sample’s mass density was observed to alter as the lead oxide content rose. Scanning electron microscope (SEM) images of the three phases revealed that different Ca-O and Cu-O layers can cause different grain sizes, characterized by elongated thin grains, without a preferred orientation.

United States Nuclear Regulatory Commission (U.S. NRC) specifies regulations on obtaining licenses and describes the technical position on the average waste concentration, also known as Concentration Averaging and Encapsulation Branch Technical Position (CA BTP); CA BTP helps classify blendable waste and discrete items and address concentration averaging. The technical position details are reviewed and compared in a real environment in Korea. A few cases of concentration averaging based on the application of CA BTP to domestic radioactive waste are presented, and the feasibility of the application is assessed. The radioactive waste considered herein does not satisfy the Disposal Concentration Limit (DCL) of the second-phase disposal facility while applying the preliminary classification. However, if CA BTP is applied when the radioactive waste is mixed with other radioactive waste items in a large and heavy container, it can be disposed of at the second-phase disposal facility in Gyeongju Repository. To apply the CA BTP of the U.S. NRC, it is necessary to investigate the safety assessment conditions of the US and Korea.

The safe disposal of high-level radioactive waste (HLW), including the discharged spent nuclear fuel (SNF) and contaminated by-products produced from relevant chemical treatments, has become a serious pending problem for numerous countries that operate the nuclear power plants. The deep geological disposal (DGD) has thus far been considered the most proven and viable solution for isolation of the HLW and preventing any significant release of radionuclides into the biosphere. The DGD system consists of the multiple engineered and natural barrier components. Among them, the montmorillonite-based buffer and tunnel backfills are designed to perform the two major geochemical functions: 1) preventing the ingress of groundwater and any chemicals that compromise the safety of waste canister and 2) retarding the migration of released radionuclides by providing sufficient chemisorption sites. Therefore, it is essential to investigate the sorption mechanism of radionuclides onto montmorillonite and develop a thermodynamic reaction model in advance in order to accurately predict the long-term performance of engineered barriers and to reduce the uncertainties in the safety assessment of a deep geological repository (DGR) ultimately; thus far, sorption of chemical species onto mineral adsorbents has been widely described based on the concept of sorption-desorption distribution coefficient (Kd), the value of which is intrinsically conditional, and active scientific efforts have been made to develop robust thermodynamic sorption models which offer the potential to improve confidence in demonstration of radionuclide migration under a wide range of geochemical conditions. The natural montmorillonites are generally classified into Na-type or Ca-type according to its exchangeable cation, and the Ca-montmorillonite containing clays are being considered as candidate materials for the engineered barriers of DGR in several countries; they generally have advantages of higher thermal conductivity and lower price than the Na-montmorillonite based clays, but their sorption capacities are still comparable. In this framework, we aimed to investigate the chemical interactions of Ca-montmorillonite with selenite [Se(IV)], which is a major oxyanionic species in terms of HLW disposal, and develop a reliable thermodynamic sorption model (TSM). The present work summarizes the characterization of Ca-montmorillonite separated from the newly adopted reference bentonite (Bentonil-WRK) by means of XRD, BET, FTIR, CEC measurement, and acid-base titration. Further, its sorption behaviors with aqueous selenite species under aqueous conditions of S/L = 5 g/L, I = 0.01-0.1 m CaCl2, pH = 4.5-8.5, pCO2 = 10-3.5 atm, and T = 25°C were examined, and the resulting thermodynamic data are discussed as well.

Porphyromonas gingivalis, a major pathogen of chronic periodontitis, colonizes in subgingival crevice and affects surrounding oral tissues, especially in periodontitis patients. Oral cancer mainly occurs in old-aged persons, and are exposed to the P. gingivalis, released from periodontitis, one of the most common inflammatory disease of oral cavity. Thus oral cancer cells may be infected with P. gingivalis, and its biologic behavior are autologously and/or heterogeneously modulated by altering gene expression. Exosomes which are derived from cells contain not only coding genes but also non-coding RNAs such as long non-coding RNAs, miRNA, and piRNAs. Here, to investigate the effect of P. gingivalis on oral cancer cells and to gain insight into the crosstalk between inflammatory signal from tumor microenvironment and oral cancer, we observed miRNA profiles of exosomes from P. gingivalis–infected oral cancer cells. Upregulation of 6 miRNAs, miR-203-3p, miR-6516-3p, miR-483-5p, miR-1275, miR-8485, and miR-19a-3p, were observed whereas 14 miRNAs including let-7a-3p, miR-106a-5p were downregulated. In addition, KEGG pathway analysis using the upregulated- and downregulated- miRNAs showed association with cell adhesion molecules pathway and ECM-receptor interaction pathway, respectively. These findings suggest that P. gingivalis could modulate biologic behavior of oral cancer cells through changes of exosomal miRNAs.

Nuclear spent fuel (SNF) disposal in deep geological repositories is considered as one of sound options for the long-term and safe sequestration of radiotoxic SNF and the sustainable use of nuclear energy. The chemical behaviors of various radionuclides originated from SNF should be well understood to evaluate the migrational behaviors of radionuclides and their reactions and interactions with various geochemical components. Formation of secondary minerals, colloids, other insoluble precipitates is of interest since the concentrations of radionuclides in groundwaters can be limited by the solubility of those solid phases. Particularly when evaluating their solubility, the use of well-defined solid materials in terms of chemical composition and molecular structure is crucial to obtain reliable measurement results. In this study, a synthetic calcium uranyl silicate (Ca-U(VI)-silicate, or uranophane) was prepared and characterized by using various analytical methods including powder X-ray diffraction (pXRD), scanning electron microscopy/energy dispersive X-ray spectrometry (SEM/EDX), and vibrational (FTIR and Raman) spectroscopies. Uranyl silicate minerals are significant to the disposal of nuclear wastes. Our simulation demonstrates that uranophane (Ca[UO2SiO3OH]2·5H2O), one having a U:Si ratio of 1:1, can be a mineral species limiting U(VI) solubility under groundwater conditions in Korea. For the preparation of Ca-U(VI)-silicate, we applied a two-step hydrothermal synthetic procedure reported in literature with modification. Briefly, we conclude that the obtained mineral phase is the ‘α-uranophane’; our characterization results show that the structural and spectroscopic properties of the synthetic Ca-U(VI)-silicate agree well with those of α-uranophane. For instance, the pXRD patterns obtained from the solid show nearly identical diffraction peak positions with those from the reference XRD pattern. From IR and Raman spectroscopy it is noticed that the stretching modes of UO2 2+ and SiO4 4- ions result in strong absorption bands in a region of 700 ~ 1,100 cm-1. Elemental compositions of the synthetic solids were also estimated by using EDX analysis, which results in a Ca:U:Si ratio close to 1:2:2 on average. However, we found that it is difficult to obtain good crystallinity of uranophane, which can be observable by using SEM and its image analysis. We believe that this work serves as a model study to provide synthetic routes of radionuclide-related mineral phases and applicable solid phase characterization methods. In the presentation, the potential use of the U(VI)-silicate solid phase for the upcoming groundwater solubility measurements will be discussed. Keywords: Hexavalent Uranium, Silicate

Store-operated Ca2+ entry (SOCE) represents one of the major Ca2+ entry routes in non-excitable cells. It is involved in a variety of fundamental biological processes and the maintenance of Ca2+ homeostasis. The Ca2+ releaseactivated Ca2+ (CRAC) channel consists of stromal interaction molecule and Orai; however, the role and action of Homer proteins as an adaptor protein to SOCE-mediated Ca2+ signaling through the activation of CRAC channels in non-excitable cells still remain unknown. In the present study, we investigated the role of Homer2 in the process of Ca2+ signaling induced by the interaction between CRACs and Homer2 proteins in non-excitable cells. The response to Ca2+ entry by thapsigargin-mediated Ca2+ store depletion remarkably decreased in pancreatic acinar cells of Homer2–/– mice, as compared to wild-type cells. It also showed critical differences in regulated patterns by the specific blockers of SOCE in pancreatic acinar cells of Homer2–/– mice. The response to Ca2+ entry by the depletion in Ca2+ store markedly increased in the cellular overexpression of Orai1 and STIM1 as compared to the overexpression of Homer2 in cells; however, this response was remarkably inhibited by the overexpression of Orai1, STIM1, and Homer2. These results suggest that Homer2 has a critical role in the regulatory action of SOCE activity and the interactions between CRAC channels.