In the present study, a novel pH-sensitive hydrogel composite of pectin-grafted-poly (acrylic acid-co-itaconic acid)/MWCNTs- COOH was prepared by using graft copolymerization of acrylic acid and itaconic acid on pectin backbone with incorporation of MWCNTS- COOH. The prepared hydrogel composite has been employed for the adsorption and controlled release of the diclofenac sodium (DS) drug. The hydrogel composite was characterized by the analysis methods: FTIR, XRD, SEM, and TGA to analyze structural characteristics before and after DS drug adsorption. The swelling ratio of the hydrogel composite was investigated at different pH values from pH 1.2 to 10. According to the results, the swelling ratio of the hydrogel composite was found 4195% at pH 7.4. Adsorption process parameters such as pH, contact time, adsorbent dose, and temperature were investigated and found to have a significant influence on DS drug adsorption. The maximum DS drug loading through adsorption of 91% was obtained at pH 3, adsorbent dose of 0.05 g, contact time of 150 min, and temperature of 15 °C. The adsorption isotherm and kinetic results were well-fitted to Freundlich and second-order models. Thermodynamic parameters including changes in Gibb’s free energy, enthalpy, and entropy suggested that the adsorption of DS drug onto hydrogel composite was a spontaneous and exothermic process. The in vitro drug release experiment showed that the cumulative release of DS drug from hydrogel composite after 35 h was significantly higher in simulated intestinal fluid at pH 7.4 than in simulated gastric fluid at pH 1.2.
The objective of this study is to analyze the indoor air quality of multi-use facilities using an IoT-based monitoring and control system. Thise study aims to identify effective management strategies and propose policy improvements. This research focused on 50 multi-use facilities, including daycare centers, medical centers, and libraries. Data on PM10, PM2.5, CO2, temperature, and humidity were collected 24 hours a day from June 2019 to April 2020. The analysis included variations in indoor air quality by season, hour, and day of the week (including both weekdays and weekends). Additionally, ways to utilize IoT monitoring systems using big data were propsed. The reliability analysis of the IoT monitoring network showed an accuracy of 81.0% for PM10 and 76.1% for PM2.5. Indoor air quality varied significantly by season, with higher particulate matter levels in winter and spring, and slightly higher levels on weekends compared to weekdays. There was a positive correlation found between outdoor and indoor pollutant levels. Indoor air quality management in multi-use facilities requires season-specific strategies, particularly during the winter and spring. Furhtermore, enhanced management is necessary during weekends due to higher pollutant levels.
Flexible self-supported laser-induced graphene (LIG) electrode devices were facilely fabricated through laser ablation technique by employing commercial polyimide film as the precursor material. Compared with the widely used traditional glassy carbon electrodes, the resulted LIG electrodes displayed abundant porous structure and surface defects. Notably, the onestep yielded LIG electrode devices were endowed with large electrochemically active surface area and accelerated electron transfer ability. Benefiting from its superior electrochemical property, these unmodified LIG electrodes exhibited remarkable enhanced electrochemical oxidation reactivity toward the food additive molecule Allura Red. Based on the augmented oxidation signal of Allura Red molecules on the LIG electrodes, a novel electrochemical sensor with high sensitivity for the detection of Allura Red was successfully developed. The sensor demonstrated a linear detection range spanning from 5 nM to 1 μM and exhibited a detection limit as low as 2.5 nM. Besides, the sensitivity was calculated to be 240.62 μA μM−1 cm− 2. More importantly, the sensor manifested outstanding stability, reproducibility, and practicality, further emphasizing its potential for real-world application.
Sulfamonomethoxine (SMM) is widely used to inhibit Gram-positive and Gram-negative bacteria, and improper use of SMM is detrimental to human health and ecological stability. Therefore, a sensitive determination method is of great importance for monitoring SMM residues in water, meat, milk, eggs, etc. Herein, a Pt-functionalized S-doped graphitic carbon nitride (Pt/Sg- C3N4) was constructed for the electrochemical determination of SMM. The as-developed Pt3/ S3-g-C3N4 sensor showed a significant SMM determination performance. The electrochemical oxidation of SMM on Pt3/ S3-g-C3N4/GCE involves two electron transference and was limited by a diffusion process. The as-developed Pt3/ S3-g-C3N4/GCE sensor has good linearity in a wide range of 0.1–120 μmol/L and a remarkably low limit of detection (LOD) of 0.026 μmol/L for SMM determination. In addition, the sensor has high selectivity and anti-interference properties for SMM detection. Furthermore, this Pt3/ S3-g- C3N4/GCE sensor has good reproducibility and stability. Moreover, the recoveries were in the range of 89.6–112.2% for the detection of the SMM in a real sample of egg. The proposed Pt3/ S3-g-C3N4/GCE sensor shows great potential for practical applications in detecting trace amounts of antibiotics.
The blackish cicada, Cryptotympana atrata Fabricius, 1775 (Hemiptera: Cicadidae) was originally distributed mainly in the southernmost remote island, Jeju and rarely throughout low lands in South Korea, but has been explosively increased at the urban areas, where annual temperature is higher. In this study, we sequenced a partial mitochondrial COI from a total of 171 individuals collected throughout 12 localities in South Korea. The haplotype found with the highest frequency in Jeju island shares only with two inland localities in southern region with a low frequency, whereas the haplotype found with the highest frequency throughout inland localities was not found in Jeju island. These results showed that Jeju population, southern region, and other inland populations form somewhat different genetic groups.
4-Nitrophenol (4NP) is a vital intermediate in organic industries, and its exploitation creates serious environmental issues. We propose a fluorescence quenching-based strategy with nitrogen and sulfur co-doped carbon dots (NS-CDs) for highly sensitive 4NP detection with excellent selectivity. The NS-CDs are produced through the hydrothermal process, in which citric acid serves as a carbon source and cysteamine hydrochloride as a source of N and S. The effect of doping was also studied by synthesizing undoped CDs and examining their properties. As-developed NS-CDs exhibit a bright cyan blue color with maximum emission centered at 465 nm. The fluorescence of NS-CDs is significantly quenched in an approximately linear fashion with increasing 4NP concentration (7.5–97.5 μM). The inner filter effect (IFE) and static quenching (SQ) between NS-CDs and 4NP are responsible for such fluorescence reduction. The fluorimetry technique enables the quantification of 4NP with a limit of detection (LOD) of about 0.028 μM. Moreover, the fluorescence quenching is tested for several other chemical compounds but they generate false quenching signals; only 4NP leads to fluorescence quenching of NS-CDs, demonstrating excellent selectivity. The “turn-off” fluorescence properties and visually apparent color change of the fluorescent probe reveal the excellent performance for 4NP sensing. The NS-CDs’ capability of quantifying 4NP in real water samples (tap water and drinking water) produces an excellent recovery rate ranging between 96.24 and 98.36%.
A semi-natural composite of κ-carrageenan and bentonite, two natural biopolymers, was synthesized through free radical polymerization. This synthesis aimed to obtain a biodegradable, biocompatible, and swellable composite that is environmentally friendly. The components used in this synthesis are readily available, making it economically feasible and promising for potential biomedical applications. The composite is pH-responsive and intended for oral delivery of metformin hydrochloride and aminophylline, which have low bioavailability and undesirable side effects, respectively. The organic composite exhibits the advantage of reducing drug release in the acidic gastric medium. This composite is a stimuli-responsive polymeric material that has garnered significant attention in recent years for its application in oral drug delivery systems. These materials enable site-specific and controlled drug release while minimizing toxicity. The carrageenan-g-poly(acrylamide-co-acrylic acid)/bentonite composite was characterized using Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), transmission electron microscopy (TEM), and field emission scanning electron microscopy (FE-SEM), which confirmed the successful synthesis of the composite. The swelling behaviour and point of zero charge of the composite were studied at different pH values, which showed a strong influence on the swelling properties of the composite. The drug loading capacity of the composite was measured at pH 5.3, and it was 70.60 mg/g for metformin and 95.66 mg/g for aminophylline at pH(3). The in vitro release profile of both drugs from the composite was also affected by the ionic strength, and it exhibited a lower release rate with higher salt concentration. The maximum release percentage of the drugs from carrageenan-g-poly(acrylic acid-acrylamide)/bentonite in simulated gastric, intestinal, and colon fluids was achieved within 40 h. The maximum release was 80% for metformin in simulated intestinal fluid (SIF) and 75% for aminophylline after 40 h.
In this paper, a simple, cost-effective, and efficient electrochemical sensor for molecular imprinting melatonin was established. The molecular imprinted films were formed by in situ electrochemical polymerization using molecular imprinting technology. The modification method, modification time and other parameters of the electrode were optimized. Under optimized conditions, the sensor responds to melatonin concentration in a linear range of 0–100 μM. The detection limit was 0.171 μM. In addition, the sensor has little response to interfering substances, such as uric acid, vitamin B6, vitamin C, and glucose, and can be tested in real samples. The recoveries were 98.73–101.60%.
In this study, we synthesized a reduced graphene oxide-manganese dioxide (rGO-MnO2) composite material using a one-step hydrothermal method and used it as a transducer layer in solid-state ion-selective electrodes (ISEs) for monitoring potassium and sodium ions in sweat. The rGO-MnO2 composite was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), revealing its unique surface morphology and crystalline structures. Electrochemical characterizations, including cyclic voltammetry (CV) and potential response testing, demonstrated the excellent performance of the rGO-MnO2 composite material as a transducer layer in ISEs. The fabricated electrodes displayed good linear responses to potassium and sodium ions, with a voltage response of 36.4 mV and 47.6 mV per unit concentration change, respectively. The electrodes also exhibited improved resistance to gas interference, such as O2, N2, and CO2. We utilized these ISEs to measure changes in potassium and sodium ion concentrations in sweat samples collected over nine days of exercise, demonstrating the practical application of the rGO-MnO2-based ISEs. This work highlights the potential of using graphene/metal oxide composites as solid contact materials in ISEs for cost-effective and stable ion sensing applications.
Hypertension caused by high-fat and high-salt diets is is a well-known significant risk factor for cardiovascular and cerebrovascular diseases. In this study, to confirm the relationship between hypertension and immune cells, angiotensin (Ang) II was administered to Dahl salt-sensitive (SS) rats and Dahl salt-resistant (SR) rats. Then the expression of immune cells and the proinflammatory cytokines were compared between the SS and SR rats. It was observed that after administration of Ang II (50ng/kg/min) for three weeks, blood pressure was increased in the SS rats, but there was no significant change in the SR rats. In addition, the expression of T helper (Th) cells and Th 17 cells in the spleen and the expression of Th cell Rorγt and regulatory T regulatory (Treg) cells in the peripheral blood mononuclear cells did not show a significant difference between the two experimental groups even after the administration of Ang II.IL-1β expression was significantly increased in the kidney tissue of the SS rats, while there was no significant difference in the IL-6 expression in all the experimental groups. The results of this study suggest that Ang II induces hypertension by stimulating IL-1β secretion from renal macrophage in SS rats.
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.
Sulfur and nitrogen co-doped carbon dots (NSCDs) were quickly synthesized by the microwave-assisted method from triammonium citrate and thiourea. NSCDs showed a quantum yield of 11.5% with excitation and emission bands at 355 and 432 nm, respectively. Also, a fluorescence quenching was observed in the presence of Pb(II) ions, and the as-synthesized CDs were used as a sensitive probe for detecting Pb(II) in water and food samples. The results showed the optimal conditions for Pb(II) determination were CDs concentration of 0.02 mg mL− 1 at pH 6.0–7.0 and an incubation time of 20 min. The relative fluorescence intensity of NSCDs was proportional to Pb(II) concentrations in the range of 0.029–2.40 and 2.40–14.4 μmol L− 1 with a correlation coefficient (R2) of 0.998 and 0.955, respectively, and a detection limit of 9.2 × 10– 3 μmol L− 1. Responses were highly repeatable, with a standard deviation below 3.5%. The suggested method demonstrates the potential of a green, fast, and low-cost approach for Pb(II) determination in water, tea, and rice samples with satisfying results.
2021년 7월 자치경찰제가 실시되면서, 지역 안전에 대한 관심이 고조 되었다. 지금까지 지역 안전은 전통적 의미의 치안 관점에서 접근하였으 나, 안전에 대한 여성의 두려움이 증가하면서, 지역에서의 안전이 더이상 치안의 차원에 머무를 수 없게 되었다. 그러나, 지역 안전을 확인할 수 있는 안전지표는 안전에 대한 취약성을 주로 측정하고 있어, 여성의 범 죄에 대한 두려움이나 예방적 차원의 지표는 포함되어 있지 않았다. 따 라서, 본 연구는 지역의 안전을 측정할 수 있는 새로운 안전지표의 구성 이 필요하며, 새로운 안전지표는 성인지적 관점의 적용으로부터 출발하 였다. 새로운 안전지표는 기존 안전이론과 함께 성인지 감수성 이론에 기반하여, 4개 영역 22개 지표를 구성하였다. 이 연구는 새로운 안전지 표를 개발하기 위한 것으로 지표가 적합한지를 탐색적으로 조사하였다. 이를 위해 성인지 전문가와 자치경찰 전문가를 대상으로 델파이 조사를 실시한 후 적합한 지표를 제시하였다. 조사 결과, 영역별 적합도는 높은 편이었고, 22개 세부 지표 가운데 14개 지표는 적합, 1개 지표는 부적 합, 7개 지표는 고려할 필요가 있는 것으로 나타났다. 이러한 결과는 향 후 자치경찰제 실시에 따른 지역 안전 지표를 구성하는 데 기여할 것으 로 기대할 수 있다.
황련(Coptis Japonica)의 뿌리로 제조한 황련 추출물 화장품이 민감한 피부에도 안전한지 검 증하기 위해 민감성 피부를 대상으로 인체 첩포 시험을 실시하였다. 젖산 자상 검사 결과 민감성 피부 로 판정한 총 32명의 시험대상자에게 황련 추출물을 2% 배합한 가용화 에센스를 시험대상자 등 부위에 20 ㎕ 취하여 24 h 동안 폐쇄 첩포한 후 이를 제거하고 30 min과 24 h 후의 시험 부위를 피부과 전문 의가 육안으로 관찰하여 피부 자극 지수를 산출하였다. 그 결과 육안으로 이상 반응이 확인되지 않았고 자극 지수가 총 0점으로 나타나 황련 추출물 2%를 배합한 화장품이 민감한 피부에 안전한 것을 확인하 였다. 다수의 황련 연구에서 항균, 항산화, 항염 등의 활성이 밝혀지고 화장품 소재로 이용 가능성이 보 고되고 있지만 본 연구를 통해 황련 추출물 화장품이 민감한 피부에도 안전한 것으로 나타나 향후 황련 화장품의 무자극 또는 저자극의 소재연구에서 본 연구가 기초 자료로 활용될 것으로 기대된다.
In this study, we evaluate artificial neural network (ANN) models that estimate the positions of gamma-ray sources from plastic scintillating fiber (PSF)-based radiation detection systems using different filtering ratios. The PSF-based radiation detection system consists of a single-stranded PSF, two photomultiplier tubes (PMTs) that transform the scintillation signals into electric signals, amplifiers, and a data acquisition system (DAQ). The source used to evaluate the system is Cs-137, with a photopeak of 662 keV and a dose rate of about 5 μSv/h. We construct ANN models with the same structure but different training data. For the training data, we selected a measurement time of 1 minute to secure a sufficient number of data points. Conversely, we chose a measurement time of 10 seconds for extracting time-difference data from the primary data, followed by filtering. During the filtering process, we identified the peak heights of the gaussian-fitted curves obtained from the histogram of the time-difference data, and extracted the data located above the height which is equal to the peak height multiplied by a predetermined percentage. We used percentage values of 0, 20, 40, and 60 for the filtering. The results indicate that the filtering has an effect on the position estimation error, which we define as the absolute value of the difference between the estimated source position and the actual source position. The estimation of the ANN model trained with raw data for the training data shows a total average error of 1.391 m, while the ANN model trained with 20%-filtered data for the training data shows a total average error of 0.263 m. Similarly, the 40%-filtered data result shows a total average error of 0.119 m, and the 60%-filtered data result shows a total average error of 0.0452 m. From the perspective of the total average error, it is clear that the more data are filtered, the more accurate the result is. Further study will be conducted to optimize the filtering ratio for the system and measuring time by evaluating stabilization time for position estimation of the source.
Licensees are required to protect critical digital assets (CDAs) in nuclear facilities against cyber-attacks, up to and including design basis threat (DBT), according to「ACT ON PHYSICAL PROTECTION AND RADIOLOGICAL EMERGENCY」. However, CDAs may be excluded from cyber security regulations at nuclear power plant decommissioning, and this may lead to severe consequences if the excluded CDAs contain sensitive information such as the number and location of nuclear fuels and information on security officers. In that case, that information could be leaked to the adversary without adequately removing the information before discarding the CDAs. It can be potentially abused to threaten nuclear facilities inducing radiological sabotage and nuclear material theft. So, controls of sensitive information are needed. This study aims to derive regulatory improvements related to discarding CDAs that have sensitive information by analyzing foreign cases such as IAEA and U.S. NRC. The sensitive information in the IAEA guide is the following: (1) details of physical protection systems and any other security measures in place for nuclear material, other radioactive material, associated facilities, and activities; (2) information relating to the quantity and form of nuclear material or other radioactive material in use or storage; (3) information relating to the quantity and form of nuclear material or other radioactive material in transport; (4) details of computer systems; (5) contingency and response plans for nuclear security events; (6) personal information; (7) threat assessments and security alerting information; (8) details of sensitive technology; (9) details of vulnerabilities or weaknesses that relate to the above topics; (10) historical information on any of the above topics. In the case of the U.S. NRC, they categorize sensitive information into three groups: (1) classified information, (2) safeguard information (SGI), (3) sensitive unclassified non-safeguards information (SUNSI). Classified information is information whose compromise would cause damage to national security or assist in manufacturing nuclear weapons. The SGI concerns the physical protection of operating power reactors, spent fuel shipments, strategic special nuclear material, or other radioactive material. Finally, SUNSI is generally not publicly available information such as personnel privacy, attorney-client privilege, and a confidential source. IAEA recommends protecting the above sensitive information in accordance with NSS No.23-G (Security of Nuclear Information), and NRC protects classified information, SGI, and SUNSI under relative laws. In the case of ROK, if security control measures are enhanced CDAs that possess sensitive information, the risk of information leakage will be decreased when those CDAs are discarded.
Wild birds, especially aquatic birds, are the natural reservoir of avian influenza virus (AIV), and many kinds of water body can be contaminated with feces of these birds. Seasonally, AIVs can be dissolved in the environmental water from the feces of the infected birds, and this water can be a target for viral detection and identification. In this study, we employed and tested three different filters for concentrating AIV, and it was shown that high concentration factor in terms of viral density could be achieved with viral samples diluted with natural water. Wild bird fecal samples containing low pathogenicity H5 AIVs were successfully concentrated with the adsorption and elution method using mixed cellulose esters membrane; the recovery rate of virus was 35.5 % and the concentration factor was about 50 on average. For the larger volume of water sample, we proved that an inline disposable filter with high surface area, 300 cm2, has a comparable concentration factor to the adsorption and elution method and the filter could be used in the field conveniently by being plugged into peristaltic pump. These validated methods for water sampling may be used as a supplementary for virological surveillance on wild migratory birds or during the epidemiological investigation on the environment near affected premises by AIV.