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4-Chloro-2-Isopropyl-5-Methylphenol Exhibits Antimicrobial and Adjuvant Activity against Methicillin-Resistant Staphylococcus aureus

  • Kim, Byung Chan;Kim, Hyerim;Lee, Hye Soo;Kim, Su Hyun;Cho, Do-Hyun;Jung, Hee Ju;Bhatia, Shashi Kant;Yune, Philip S.;Joo, Hwang-Soo;Kim, Jae-Seok;Kim, Wooseong;Yang, Yung-Hun
    • Journal of Microbiology and Biotechnology
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    • v.32 no.6
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    • pp.730-739
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    • 2022
  • Methicillin-resistant Staphylococcus aureus (MRSA) causes severe infections and poses a global healthcare challenge. The utilization of novel molecules which confer synergistical effects to existing MRSA-directed antibiotics is one of the well-accepted strategies in lieu of de novo development of new antibiotics. Thymol is a key component of the essential oil of plants in the Thymus and Origanum genera. Despite the absence of antimicrobial potency, thymol is known to inhibit MRSA biofilm formation. However, the anti-MRSA activity of thymol analogs is not well characterized. Here, we assessed the antimicrobial activity of several thymol derivatives and found that 4-chloro-2-isopropyl-5-methylphenol (chlorothymol) has antimicrobial activity against MRSA and in addition it also prevents biofilm formation. Chlorothymol inhibited staphyloxanthin production, slowed MRSA motility, and altered bacterial cell density and size. This compound also showed a synergistic antimicrobial activity with oxacillin against highly resistant S. aureus clinical isolates and biofilms associated with these isolates. Our results demonstrate that chlorinated thymol derivatives should be considered as a new lead compound in anti-MRSA therapeutics.

Self-pressurization Effect and PEMFC Performance Improvement Using Metal Foam Compression (금속 폼 압축에 의한 자가 가압 효과 및 PEMFC 성능 개선)

  • Kim, Hyeonwoo;Kim, Junbom
    • Applied Chemistry for Engineering
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    • v.33 no.6
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    • pp.618-623
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    • 2022
  • The bipolar plate is a key component of the polymer electrolyte membrane fuel cell (PEMFC) that transfers reactants and electrons, discharges water and heat as by-products, and serves as a mechanical support for the membrane electrode assembly (MEA). Therefore, the flow field structure of the bipolar plate plays an important role in improving fuel cell performance. In this study, PEMFC performance was investigated with copper foams with different compressibility ratios applied to cathode bipolar plates using a 25 cm2 unit cell. The total resistance decreased as the compressibility ratio of the metal foams increased, and, in particular, the charge transfer and mass transfer resistance were significantly improved compared to the serpentine flow field, lowering voltage loss in medium and high current density region. In the case of pressurized air reactant flow with serpentine structure, fuel cell performance was similar to that of a compressed metal foam flow field (S3) up to the medium current density region, but low performance appeared in the high current density region due to flow field structure limitations.

Optimization of extrusion cooking conditions for seasoning base production from sea mustard (Undaria pinnatifida)

  • Lee, Chaehyeon;Shin, Eui-Cheol;Ahn, Soo-Young;Kim, Seonghui;Kwak, Dongyun;Kwon, Sangoh;Choi, Yunjin;Choi, Gibeom;Jeong, Hyangyeon;Kim, Jin-Soo;Lee, Jung Suck;Cho, Suengmok
    • Fisheries and Aquatic Sciences
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    • v.25 no.3
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    • pp.175-186
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    • 2022
  • Sea mustard (Undaria pinnatifida), an important edible seaweed belonging to the brown algal family of Alariaceae, contains copious physiologically active substances. It has long been popular in Korea as a food and is frequently consumed in the form of soup. It is also commercially available as a home meal replacement. In this study, we developed a seasoning key base with a high degree of sensory preference from sea mustard using the extrusion cooking process. Extrusion cooking conditions were optimized through response surface methodology. Barrel temperature (X1, 140℃-160℃) and screw speed (X2, 158-315 rpm) were set as independent variables, and overall preference was determined as the dependent variable (Y, points). An optimal condition was obtained at X1 = 148.5℃ and X2 = 315 rpm, and the dependent variable (Y, overall acceptance) was 7.95 points, similar to the experimental value of 7.81. Umami taste had a relationship with the overall acceptance of sea mustard seasoning. In the electronic nose and tongue, increased sourness and umami intensities were associated with the highest sensory score. The samples were separated well by each characteristic via principal component analysis. Collectively, our study provides imperative preliminary data for the development of various seasonings using sea mustard.

Fast Adaptation Techniques of Compensation Coefficient of Active Noise Canceller using Binary Search Algorithm (이진 탐색 알고리즘을 이용한 능동 노이즈 제거용 보정 계수 고속 적용 기법)

  • An, Joonghyun;Park, Daejin
    • Journal of the Korea Institute of Information and Communication Engineering
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    • v.25 no.11
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    • pp.1635-1641
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    • 2021
  • Portable systems with built-in active noise control is required low power operation. Excessive anti noise search operation can lead to rapid battery consumption. A method that can adaptively cancel noise according to the operating conditions of the system is required and the methods of reducing power are becoming very important key feature in today's portable systems. In this paper, we propose the method of active noise control(ANC) using binary search algorithm in noisy systems. The implemented architecture detects a frequency component considered as noise from the input signal and by using the binary search algorithm, the system find out an appropriate amplitude value for anti-noise in a much faster time than the general linear search algorithm. Through the experimental results, it was confirmed that the proposed algorithm performs a successful functional operation.

Study of an improved and novel venturi scrubber configuration for removal of radioactive gases from NPP containment air during severe accident

  • Farooq, Mujahid;Ahmed, Ammar;Qureshi, Kamran;Shah, Ajmal;Waheed, Khalid;Siddique, Waseem;Irfan, Naseem;Ahmad, Masroor;Farooq, Amjad
    • Nuclear Engineering and Technology
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    • v.54 no.9
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    • pp.3310-3316
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    • 2022
  • Owing to the rising concerns about the safety of nuclear power plants (NPP), it is essential to study the venturi scrubber in detail, which is a key component of the filtered containment venting system (FCVS). FCVS alleviates the pressurein containment byfiltering and venting out the contaminated air. Themain objective of this research was to perform a CFD investigation of different configurations of a circular, non-submerged, self-priming venturi scrubber to estimate and improve the performance in the removal of elemental iodine from the air. For benchmarking, a mass transfer model which is based on two-film theory was selected and validated by experimental data where an alkaline solution was considered as the scrubbing solution. This mass transfer model was modified and implemented on a unique formation of two self-priming venturi scrubbers in series. Euler-Euler method was used for two-phase modeling and the realizable K-ε model was used for capturing the turbulence. The obtained results showed a remarkable improvement in the removal of radioactive iodine from the air using a series combination of venturi scrubbers. The removal efficiency was improved at every single data point.

An Empirical Study on the Effects of Export Promotion on Korea-China-Japan Using Logistics Performance Index (LPI)

  • La, Kong-Woo;Song, Jin-Gu
    • Journal of Korea Trade
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    • v.23 no.7
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    • pp.96-112
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    • 2019
  • Purpose - "Trade Facilitation" aims the easier flow of trade across borders, driven not only by effective customs administration, the efficiency of appropriate authorities, but also by telecommunications, the quality of infrastructures and competent logistics. Facilitating trade will help lower trade development costs as well as improve economic development and enhance economic benefits for emerging economies at a time when imports and exports are sent in and out across borders several times in the form of intermediate and final products. Not only that, globalization is being accelerated, which in turn increases competitiveness and this makes logistics one of the key factors when it comes to international trade. Highly efficient logistics services promote product movement, ensure product safety and delivery speed, and reduce trade costs between countries. The purpose of this study is, by using the LPI indices based on gravity model estimates, to analyze the impact of each LPI component on trade with the 20 biggest exporting countries of Northeast Asian countries-Korea, Japan, and China-which account for 19.05% of global exports. Design/methodology - Also, this study statistically analyzes the impact of trade on Northeast Asian countries' top 20 exporting countries, using the LPI indices relevant to Trade Facilitation based on the gravity model estimates. Findings - As a result, it was turned out that the distance, GDP, and the LPI components have relevant impact on the trade exports of all three countries but demonstrated little relation to the demographic perspective. Originality/value - The study also found we can increase the trade volume by improving three countries' trade partners' LPI indices since Korea, Japan, and China share most of their 20 biggest trade partners.

Incorporating concepts of biodiversity into modern aquaculture: macroalgal species richness enhances bioremediation efficiency in a lumpfish hatchery

  • Knoop, Jessica;Barrento, Sara;Lewis, Robert;Walter, Bettina;Griffin, John N.
    • ALGAE
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    • v.37 no.3
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    • pp.213-226
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    • 2022
  • Aquaculture is one of the fastest growing food producing sectors; however, intensive farming techniques of finfish have raised environmental concerns, especially through the release of excessive nutrients into surrounding waters. Biodiversity has been widely shown to enhance ecosystem functions and services, but there has been limited testing or application of this key ecological relationship in aquaculture. This study tested the applicability of the biodiversity-function relationship to integrated multi-trophic aquaculture (IMTA), asking whether species richness can enhance the efficiency of macroalgal bioremediation of wastewater from finfish aquaculture. Five macroalgal species (Chondrus crispus, Fucus serratus, Palmaria palmata, Porphyra dioica, and Ulva sp.) were cultivated in mono- and polyculture in water originating from a lumpfish (Cyclopterus lumpus) hatchery. Total seaweed biomass production, specific growth rates (SGR), and the removal of ammonium (NH4+), total oxidised nitrogen (TON), and phosphate (PO43-) from the wastewater were measured. Species richness increased total seaweed biomass production by 11% above the average component monoculture, driven by an increase in up to 5% in SGR of fast-growing macroalgal species in polycultures. Macroalgal species richness further enhanced ammonium uptake by 25%, and TON uptake by nearly 10%. Phosphate uptake was not improved by increased species richness. The increased uptake of NH4+ and TON with increased macroalgal species richness suggests the complementary use of different nitrogen forms (NH4+ vs. TON) in macroalgal polycultures. The results demonstrate enhanced bioremediation efficiency by increased macroalgal species richness and show the potential of integrating biodiversity-function research to improve aquaculture sustainability.

Development of Pore-Filled Anion-Exchange Membranes for High Performance Reverse Electrodialysis (고성능 역전기투석을 위한 세공충진 음이온교환막의 개발)

  • Kim, Do-Hyeong;Song, Hyeon-Bee;Yoon, Kyungseok;Kang, Moon-Sung
    • Membrane Journal
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    • v.32 no.5
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    • pp.336-347
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    • 2022
  • Reverse electrodialysis (RED) is one of the promising eco-friendly renewable energy technologies which can generate electricity from the concentration difference between seawater and freshwater by using ion-exchange membranes as a diaphragm. The ion-exchange membrane is a key component that determines the performance of RED, and must satisfy requirements such as low electrical resistance, high permselectivity, excellent durability, and low manufacturing cost. In this study, pore-filled anion-exchange membranes were fabricated using porous polymer substrates having various thicknesses and porosity, and the effects of ion-exchange polymer composition and membrane thickness on the power generation performance of RED were investigated. When the electrical resistance of the ion-exchange membrane is sufficiently low, it can be confirmed that the RED power generation performance is mainly influenced by the apparent permselectivity of the membrane. In addition, it was confirmed that the apparent permselectivity of the membranes can be improved through IEC, crosslinking degree, membrane thickness, surface modification, etc., and the optimum condition must be found in consideration of the trade-off relationship with electrical resistance.

Mission Management Technique for Multi-sensor-based AUV Docking

  • Kang, Hyungjoo;Cho, Gun Rae;Kim, Min-Gyu;Lee, Mun-Jik;Li, Ji-Hong;Kim, Ho Sung;Lee, Hansol;Lee, Gwonsoo
    • Journal of Ocean Engineering and Technology
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    • v.36 no.3
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    • pp.181-193
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    • 2022
  • This study presents a mission management technique that is a key component of underwater docking system used to expand the operating range of autonomous underwater vehicle (AUV). We analyzed the docking scenario and AUV operating environment, defining the feasible initial area (FIA) level, event level, and global path (GP) command to improve the rate of docking success and AUV safety. Non-holonomic constraints, mounted sensor characteristic, AUV and mission state, and AUV behavior were considered. Using AUV and docking station, we conducted experiments on land and at sea. The first test was conducted on land to prevent loss and damage of the AUV and verify stability and interconnection with other algorithms; it performed well in normal and abnormal situations. Subsequently, we attempted to dock under the sea and verified its performance; it also worked well in a sea environment. In this study, we presented the mission management technique and showed its performance. We demonstrated AUV docking with this algorithm and verified that the rate of docking success was higher compared to those obtained in other studies.

Study on the Development and Functional Characteristics of Salted Egg with Liquid Smoke

  • Putri Widyanti Harlina;Tri Yuliana;Fetriyuna;Raheel Shahzad;Meihu Ma
    • Food Science of Animal Resources
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    • v.43 no.3
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    • pp.471-490
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    • 2023
  • In this study, the duck eggs were salted with none or 2.5% and 5.0% (v/v) of liquid smoke (LS), respectively. As a control, samples salted without LS were used. The 2-thiobarbituric acid (TBA) values, 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging ability, and reducing power of the three groups were tested at 0, 7, 14, and 21 and 28 days to determine the effects of LS on the antioxidant activity of treated eggs. In addition, gas chromatography-mass spectrometry (GC-MS) and electronic nose (E-Nose) were used to analyze the volatile flavor components of fresh duck eggs, LS, control, and salted duck eggs enriched with 2.5% (v/v) LS after 28 days of salting. The TBA value considerably increased with an increase in salting period, and the treated egg's TBA value significantly associated with LS concentration. The TBA value decreased as the LS concentration increased. The amount of LS present was highly associated with their capacity to scavenge DPPH radicals. The reducing power of the samples was substantially correlated with the LS concentration, and the reducing power increased with increasing LS concentration. The GC-MS data revealed that phenols and ketones were the predominant chemicals present in the LS, and they were also found in the eggs added to the LS even though they were absent in the fresh eggs and control. The flavor of the control group and treated eggs with LS differed significantly, according to the principal component analysis and radar map of the E-nose. The texture study results revealed that the LS significantly impacted the hardness, cohesiveness, and chewiness of eggs.