• Analytical Science and Technology
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• v.21 no.5
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• pp.397-402
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• 2008

Uranium dioxide was dissolved with nitric acid and a trace amount of HF. The analytical conditions of a spectrophotometer were investigated to determine a trace amount of silicon in the uranium matrices without a separation process. The effects of a trace amount of HF on the determination of silicon were examined. Boric acid was used to eliminate HF the interference in the colorimetric process. The recovery of silicon in the presence of a trace amount of HF in uranium solutions with or without saturated boric acid was $103.3{\pm}0.8$ and $76.6{\pm}6.8%$, respectively. The amount of saturated boric acid did not affect the recovery of the silicon. Therefore it was possible for this procedure to measure a trace amount of silicon in a uranium matrix without a separation by a UV-VIS spectrophotometry.

• Advances in concrete construction
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• v.16 no.1
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• pp.69-78
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• 2023

This investigation delves into the adverse repercussions stemming from the impact of arsenic on steel pipes concealed within soil designated for rice cultivation. Simultaneously, the study aims to ascertain effective techniques for detecting arsenic in the soil and to provide strategies for mitigating the corrosion of steel pipes. The realm of nanotechnology presents promising avenues for addressing the intricate intersection of renewable energy, oil, and environmental pollution from a novel perspective. Nanostructured materials, characterized by distinct chemical and physical attributes, unveil novel pathways for pioneering materials that exert a substantial impact across diverse realms of food production, storage, packaging, and quality control. Within the scope of the food industry, the scope of nanotechnology encompasses processes, storage methodologies, packaging paradigms, and safeguards to ensure the safety of consumables. Of particular note, silver nanoparticles, in addition to their commendable antibacterial efficacy, boast anti-fungal and anti-inflammatory prowess, environmental compatibility, minimal irritability and allergenicity, resilience to microbial antagonism, thermal stability, and robustness. Confronting the pressing issue of arsenic contamination within both environmental settings and the food supply is of paramount importance to preserve public health and ecological equilibrium. In response, this study introduces detection kits predicated upon silver nanoparticles, providing an expeditious and economically feasible avenue for identifying arsenic concentrations ranging from 0.5 to 3 ppm within rice. Subsequent quantification employs Hydride Atomic Absorption Spectroscopy (HG-AAS), which features a detection threshold of 0.05 ㎍/l. A salient advantage inherent in the HG-AAS methodology lies in its capacity to segregate analytes from the sample matrix, thereby significantly reducing instances of spectral interference. Importantly, the presence of arsenic in the soil beneath rice cultivation establishes a causative link to steel pipe corrosion, with potential consequences extending to food contamination-an intricate facet embedded within the broader tapestry of renewable energy, oil, and environmental pollution.

• Journal of the Semiconductor & Display Technology
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• v.22 no.3
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• pp.28-35
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• 2023

Moiré patterns emerge due to the interference between the non-emission area of the LED screen and the grid line in an image sensor of a video recording device when taking a video in the presence of the LED screen. To reduce the moiré intensity, we have fabricated an anti-moiré filter using hollow glass microspheres (HGMs) by slot-die coating. The LED screen has a large non-emission area because of a large pitch (distance between LED chips), causing more severe moiré phenomenon, compared with a display panel having a very narrow black matrix (BM). It is shown that HGMs diffuse light in such a way that the periodicity of the screen is broken and thus the moiré intensity weakens. To quantitatively analyze its moiré suppression capability, we have calculated the spatial frequencies of the moiré fringes using fast Fourier transform. It is addressed that the moiré phenomenon is suppressed and thus the amplitude of each discrete spatial frequency term is reduced as the HGM concentration is increased. Using the filter with the HGM concentration of 9 wt%, the moiré fringes appeared depending sensitively on the distance between the LED screen and the camera are almost completely removed and the visibility of a nature image is enhanced at a sacrifice of luminance.

• Analytical Science and Technology
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• v.31 no.4
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• pp.171-178
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• 2018

Recently, for successful lactation, many breastfeeding mothers seek various products, including herbal medicine, dietary supplements, and prescribed medicines, to improve milk production. As demand for galactogogues grows, it is highly possible that pharmaceutical galactogogues may be adulterated with illegal products to maximize their efficacy. For continuous control and supervision of illegal products, we developed and validated a simple and sensitive LC-MS/MS method capable of simultaneously determining five galactogogues. Chromatographic separation was conducted using an Agilent Poroshell $120SB-C_{18}$ column with a mobile phase consisting of 20 mM ammonium formate (pH 5.4) and 100 % acetonitrile. The total run time was 13 min per analyte. The proposed method was performed according to the guidelines of the International Conference of Harmonization and it produced reliable results. This method showed high sensitivity and specificity, with a limit of detection (LOD) and limit of quantitation (LOQ) of 0.01-0.82 ng/mL and 0.02-2.45 ng/mL, respectively, for the solid- and liquid-type samples. Specificity was evaluated by analyzing matrix-blank samples spiked with the target compounds at LOQ levels, which provided a good separation of all peaks without interference. Additionally, the repeatability and intermediate precision were typically <15 %, whereas the recovery was 80-120 % of the values obtained using blank samples. Thus, we concluded that this method could be used for the identification and quantification of galactogogues in food or herbal products.

• Journal of the Korean Chemical Society
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• v.53 no.1
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• pp.27-33
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• 2009

A sensitive technique for the determination of trace Cd(II) in various real samples after preconcentration onto microcrystalline p-dichlorobenzene loaded with 2-mercaptobenzothiazole was developed. Several experimental conditions such as the pH of the sample solution, the amount of chelating agent 2-mercaptobenzothiazole, the amount of adsorbent p-dichlorobenzene-2-MBT, and the flow rate of sample solution were optimized. The interfering effects of various concomitant ions were investigated. Cu(II) interfered with more seriously than any other ions. However, the interference by Cu(II) could be overcome sufficiently by adjusting tartrate ion concentration to be 0.01M or by controlling the amount of 2-mercaptobenzothiazole contained in 0.20 g p-dichlorobenzene to be 0.12 g. The dynamic range, the correlation coefficient ($R^2$) and the detection limit obtained by this proposed technique were $0.5{\sim}30$ ng $mL^{-1}$, 0.9962, and 0.39 ng $mL^{-1}$, respectively. Thus, good results were obtained by the use of p-dichlorobenze as adsorbent matrix. For validating this proposed technique, the aqueous samples(wastewater, stream water, and reservoir water) and the plastic sample were used. Recovery yields of $93{\sim}104$ % were obtained. By F test, these measured data were not different from ICP-MS data at 95 % confidence level. Based on the results from the experiment, it was found that this proposed technique could be applied to the preconcentration and determination of Cd(II) in various real samples.

• Analytical Science and Technology
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• v.7 no.1
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• pp.33-39
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• 1994

The purpose on this study was to develop a new improved chromatographic method for determination of trace phenols from environmental waste water. The research was carried out with selected 8 phenols, and solid-phase extraction was employed as sample pretreatment method. The coupling of XAD-4 and Dowex $1{\times}8$ resin as preconcentration column increased the selectivities toward interferences coexisted in matrix. Automation was accomplished with on-line process of pretreatment and HPLC system. After elution of sample through XAD-4 column, phenols were adsorbed by dispersion force, then displaced from it by ACN basified, simultaneously and selectively readsorbed via anion exchange on Dowex $1{\times}8$. Dowex $1{\times}8$ column was washed by water. Phenols readsorbed were removed from Dowex $1{\times}8$ column by a minimum volumn of methanol containing HCl. Each pretreatment step was connected by switching valves and the eluate was directly on-line injected to obtain fast and reliable results into the HPLC. Recovery of phenols was greater than 90%. To examine utility of this method, analysis of phenols from laboratory waste water sample which was added some organic pollutants to find with phenols on environmental waste water were also accomplished without their interference effects.

• Microbiology and Biotechnology Letters
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• v.40 no.2
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• pp.83-91
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• 2012

Quorum sensing (QS) is a cell-to-cell communication system, which is used by many bacteria to regulate diverse gene expression in response to changes in population density. Bacteria recognize the differences in cell density by sensing the concentration of signal molecules such as N-acyl-homoserine lactones (AHL) and autoinducer-2 (AI-2). In particular, QS plays a key role in biofilm formation, which is a specific bacterial group behavior. Biofilms are dense aggregates of packed microbial communities that grow on surfaces, and are embedded in a self-produced matrix of extracellular polymeric substances (EPS). QS regulates biofilm dispersal as well as the production of EPS. In some bacteria, biofilm formations are regulated by c-di-GMP-mediated signaling as well as QS, thus the two signaling systems are mutually connected. Biofilms are one of the major virulence factors in pathogenic bacteria. In addition, they cause numerous problems in industrial fields, such as the biofouling of pipes, tanks and membrane bioreactors (MBR). Therefore, the interference of QS, referred to as quorum quenching (QQ) has received a great deal of attention. To inhibit biofilm formation, several strategies to disrupt bacterial QS have been reported, and many enzymes which can degrade or modify the signal molecule AHL have been studied. QQ enzymes, such as AHL-lactonase, AHL-acylase, and oxidoreductases may offer great potential for the effective control of biofilm formation and membrane biofouling in the future. This review describes the process of bacterial QS, biofilm formation, and the close relationship between them. Finally, QQ enzymes and their applications for the reduction of biofouling are also discussed.

• Korean Journal of Food Science and Technology
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• v.42 no.4
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• pp.390-397
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• 2010

Residual solvents in foods are defined as organic volatile chemicals used or produced in manufacturing of extracts or additives, or functional foods. The solvents are not completely eliminated by practical manufacturing techniques and they also may become contaminated by solvents from packing, transportation or storage in warehouses. Because residual solvents have no nutritional value but may be hazardous to human health, there is a need to remove them from the final products or reduce their amounts to below acceptable levels. The purpose of this study was to develop and evaluate an analytical method for the screening of residual solvents in health functional foods. Furthermore, the aim of this study was to constitute a reasonable management system based on the current state of the market and case studies of foreign countries. Eleven volatile solvents such as MeOH, EtOH, trichloroethylene and hexane were separated depending on their column properties, temp. and time using Gas Chromatography (GC). After determining the GC conditions, a sample preparation method using HSS (Head Space Sampling) was developed. From the results, a method for analyzing residual solvents in health functional foods was developed considering matrix effect and interference from the sample obtained from the solution of solvents-free health functional foods spiked with 11 standards solutions. Validation test using the developed GC/HSS/MS (Mass Spectrometry) method was followed by tests for precision, accuracy, recovery, linearity and adequate sensitivity. Finally, examination of 104 samples grouped in suits was performed by the developed HSS/GC/MS for screening the solvents. The 11 solvents were isolated from health functional foods based on vapor pressure difference, and followed by separation within 15 minutes in a single run. The limt of detection (LOD), limit of quantification (LOQ), recovery and coefficient of variation (C.V.) of these compounds determined by the HSS/GC/MS were found to be 0.1 pg/mL, 0.1-125 pg/g, 51.0-104.6%, and less than 15%, respectively. Using the developed HSS/GC/MS method, residual solvent from 16 out of 104 health functional products were detected as a EtOH. This method therefore seems t o be a valuable extension ofanalytical method for the identification of residual solvents in health functional food.

• Analytical Science and Technology
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• v.16 no.5
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• pp.391-398
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• 2003

Basic research for the determination of boron content in biological sample has been carried out using the PGAA facility of the 24MW research reactor(HANARO). For investigation of characteristics for the measurement condition, neutron flux and its homogeneity were measured at irradiating geometry. The size of thermal neutron beam collimated from beam guide is $2{\times}2cm^2$ at the sample position. The neutron flux measured was the range of $1.0{\sim}6.5{\times}10^7n{\cdot}cm^{-2}{\cdot}s^{-1}$, and flux distribution from center within the radius of 4.5 mm and 9.0 mm was $5.77{\pm}0.71{\times}10^7n{\cdot}cm^{-2}{\cdot}s^{-1}$ and $4.68{\pm}1.64{\times}10^7n{\cdot}cm^{-2}{\cdot}s^{-1}$, respectively. Accordingly, sample size is adjusted within 10 mm for a homogeneous irradiation of high quality. Measurement system is designed to reduce the background source by Compton scattering and to improve the analytical sensitivity. To investigate the energy calibration and Compton suppression effect of gamma-ray counting system, the background conditions on both of Compton and single-mode were measured using NaCl standard. On the other hand, degree of spectral interference for sodium 472 keV peak as a matrix effect in the sample is established for an accurate boron analysis, and then boron content in three certified reference materials (NIST SRM 1570a, 1547, 1573a) was measured by using two modes and the results were compared with each other.

• BMB Reports
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• v.53 no.6
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• pp.323-328
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• 2020

Matrix metalloproteinase 1 (MMP-1), a calcium-dependent zinccontaining collagenase, is involved in the initial degradation of native fibrillar collagen. Tissue necrosis factor-alpha (TNFα) is a pro-inflammatory cytokine that is rapidly produced by dermal fibroblasts, monocytes/macrophages, and keratinocytes and regulates inflammation and damaged-tissue remodeling. MMP-1 is induced by TNFα and plays a critical role in tissue remodeling and skin aging processes. However, the regulation of the MMP1 gene by TNFα is not fully understood. We aimed to find additional cis-acting elements involved in the regulation of TNFα-induced MMP1 gene transcription in addition to the nuclear factor-kappa B (NF-κB) and activator protein 1 (AP1) sites. Assessments of the 5'-regulatory region of the MMP1 gene, using a series of deletion constructs, revealed the requirement of the early growth response protein 1 (EGR-1)-binding sequence (EBS) in the proximal region for proper transcription by TNFα. Ectopic expression of EGR-1, a zinc-finger transcription factor that binds to G-C rich sequences, stimulated MMP1 promoter activity. The silencing of EGR-1 by RNA interference reduced TNFα-induced MMP-1 expression. EGR-1 directly binds to the proximal region and transactivates the MMP1 gene promoter. Mutation of the EBS within the MMP1 promoter abolished EGR-1-mediated MMP-1 promoter activation. These data suggest that EGR-1 is required for TNFα-induced MMP1 transcriptional activation. In addition, we found that all three MAPKs, ERK1/2, JNK, and p38 kinase, mediate TNFα-induced MMP-1 expression via EGR-1 upregulation. These results suggest that EGR-1 may represent a good target for the development of pharmaceutical agents to reduce inflammation-induced MMP-1 expression.