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877 result(s) for "Kim, Ung"
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A gift for Nai Nai
\"Struggling to crochet a lucky hat for her beloved Nai Nai's birthday, Lyn Lyn learns that the best gift of all comes from within\"-- Provided by publisher.
Deep Eutectic Solvent as Green Solvent in Extraction of Biological Macromolecules: A Review
Greater awareness of environmental sustainability has driven many industries to transition from using synthetic organic solvents to greener solvents in their manufacturing. Deep eutectic solvents (DESs) have emerged as a highly promising category of green solvents with well-demonstrated and wide-ranging applications, including their use as a solvent in extraction of small-molecule bioactive compounds for food and pharmaceutical applications. The use of DES as an extraction solvent of biological macromolecules, on the other hand, has not been as extensively studied. Thereby, the feasibility of employing DES for biomacromolecule extraction has not been well elucidated. To bridge this gap, this review provides an overview of DES with an emphasis on its unique physicochemical properties that make it an attractive green solvent (e.g., non-toxicity, biodegradability, ease of preparation, renewable, tailorable properties). Recent advances in DES extraction of three classes of biomacromolecules—i.e., proteins, carbohydrates, and lipids—were discussed and future research needs were identified. The importance of DES’s properties—particularly its viscosity, polarity, molar ratio of DES components, and water addition—on the DES extraction’s performance were discussed. Not unlike the findings from DES extraction of bioactive small molecules, DES extraction of biomacromolecules was concluded to be generally superior to extraction using synthetic organic solvents.
Concentrations of THC, CBD, and CBN in commercial hemp seeds and hempseed oil sold in Korea
•Extraction and GC/MS methods for hemp seeds and hempseed oil were developed and validated.•Concentrations of THC, CBD, and CBN in commercial hemp seeds and hempseed oil were measured.•A trend was observed by comparing THC, CBD, and CBN ratios in hemp seeds and hempseed oil. Hemp seeds and hempseed oil are marketed on- and off-line as health foods and cosmetics and have been reported to have high nutrient contents. However, because of the various side effects of cannabinoids, especially △9-tetrahydrocannabinol (THC), many countries regulate upper limits for THC in products, which creates the need for analytical techniques capable of measuring THC, cannabidiol (CBD), and cannabinol (CBN) levels in commercial hemp seeds and hempseed oil. In the present study, hemp seed and hempseed oil extracts obtained by methanol extraction, were analyzed by gas chromatography–mass spectrometry (GC/MS). Validation of the technique used was performed using calibration curves and by determining LODs, LOQs, specificities, selectivities, and intra- and inter-day precision and accuracies. In addition, matrix effects, process efficiencies, recoveries, and sample stabilities were investigated. In hemp seeds, as determined using the fully optimized method THC concentrations ranged from 0.06 to 5.91 μg/g, CBD concentrations from 0.32 to 25.55 μg/g, and CBN concentrations from 0.01 to 1.50 μg/g; CBN/THC ratios ranged from 0.1 to 1.60, and CBD/THC ratios from 0.11 to 62.56. Furthermore, the (THC + CBN)/CBD ratio of most hemp seed samples was less than one. In hempseed oil, THC concentrations ranged from 0.3 to 19.73 μg/mL, CBD concentrations from 6.66 to 63.40 μg/mL, CBN concentrations from 0.11 to 2.31 μg/mL, CBN/THC ratios from 0.12 to 0.42, and CBD/THC ratios from 3.21 to 22.50. Furthermore, (THC + CBN)/CBD ratios in all hempseed oil samples were less than one. The optimized methanol extraction-GC/MS technique was found to be satisfactory for determining THC, CBD, and CBN concentrations in hemp seeds and hempseed oil.
Effects of Alkaline Extraction pH on Amino Acid Compositions, Protein Secondary Structures, Thermal Stability, and Functionalities of Brewer’s Spent Grain Proteins
A high alkaline pH was previously demonstrated to enhance the extraction yield of brewer’s spent grains (BSG) proteins. The effects of extraction pH beyond the extraction yield, however, has not been investigated before. The present work examined the effects of extraction pH (pH 8–12) on BSG proteins’ (1) amino acid compositions, (2) secondary structures, (3) thermal stability, and (4) functionalities (i.e., water/oil holding capacity, emulsifying, and foaming properties). The ideal extraction temperature (60 °C) and BSG-to-solvent ratio (1:20 w/v) for maximizing the extraction yield were first determined to set the conditions for the pH effect study. The results showed that a higher extraction pH led to more balanced compositions between hydrophilic and hydrophobic amino acids and higher proportions of random coils structures indicating increased protein unfolding. This led to superior emulsifying properties of the extracted proteins with more than twofold improvement between pH 8 and a pH larger than 10. The extraction pH, nevertheless, had minimal impact on the water/oil holding capacity, foaming properties, and thermal denaturation propensity of the proteins. The present work demonstrated that a high alkaline pH at pH 11–12 was indeed ideal for both maximizing the extraction yield (37–46 wt.%) and proteins’ functionalities.
Inhibition of SARS-CoV-2 Virus Entry by the Crude Polysaccharides of Seaweeds and Abalone Viscera In Vitro
Much attention is being devoted to the potential of marine sulfated polysaccharides as antiviral agents in preventing COVID-19. In this study, sulfated fucoidan and crude polysaccharides, extracted from six seaweed species (Undaria pinnatifida sporophyll, Laminaria japonica, Hizikia fusiforme, Sargassum horneri, Codium fragile, Porphyra tenera) and Haliotis discus hannai (abalone viscera), were screened for their inhibitory activity against SARS-CoV-2 virus entry. Most of them showed significant antiviral activities at an IC50 of 12~289 μg/mL against SARS-CoV-2 pseudovirus in HEK293/ACE2, except for P. tenera (IC50 > 1000 μg/mL). The crude polysaccharide of S. horneri showed the strongest antiviral activity, with an IC50 of 12 μg/mL, to prevent COVID-19 entry, and abalone viscera and H. fusiforme could also inhibit SARS-CoV-2 infection with an IC50 of 33 μg/mL and 47 μg/mL, respectively. The common properties of these crude polysaccharides, which have strong antiviral activity, are high molecular weight (>800 kDa), high total carbohydrate (62.7~99.1%), high fucose content (37.3~66.2%), and highly branched polysaccharides. These results indicated that the crude polysaccharides from seaweeds and abalone viscera can effectively inhibit SARS-CoV-2 entry.
Cellulose-chitosan beads crosslinked by dialdehyde cellulose
Crosslinked cellulose-chitosan beads were obtained via dissolution-regeneration of cellulose and chitosan by a LiOH/urea aqueous solution, followed by the crosslinking of chitosan via dialdehyde cellulose (DAC). This crosslinking reaction involved the Schiff base formation between the aldehyde groups of DAC and the amino groups of chitosan and subsequent reduction. DAC was prepared through periodate oxidation of cellulose and solubilization in hot water at 100 °C for 1 h. Four grades of DAC-crosslinked cellulose-chitosan were prepared by controlling the amount of cellulose and chitosan. The DAC-crosslinked cellulose-chitosan showed higher stability in the pH range of 2–9 over a long-term 21-day test. Additionally, the DAC-crosslinked chitosan showed a higher bovine serum albumin adsorption capacity as a result of the increased amino group content due to the crosslinking between DAC and chitosan, which occurred at multiple points in spite of a lower degree in crosslinking.
Aspirin versus clopidogrel for chronic maintenance monotherapy after percutaneous coronary intervention (HOST-EXAM): an investigator-initiated, prospective, randomised, open-label, multicentre trial
Optimal antiplatelet monotherapy during the chronic maintenance period in patients who undergo coronary stenting is unknown. We aimed to compare head to head the efficacy and safety of aspirin and clopidogrel monotherapy in this population. We did an investigator-initiated, prospective, randomised, open-label, multicentre trial at 37 study sites in South Korea. We enrolled patients aged at least 20 years who maintained dual antiplatelet therapy without clinical events for 6–18 months after percutaneous coronary intervention with drug-eluting stents (DES). We excluded patients with any ischaemic and major bleeding complications. Patients were randomly assigned (1:1) to receive a monotherapy agent of clopidogrel 75 mg once daily or aspirin 100 mg once daily for 24 months. The primary endpoint was a composite of all-cause death, non-fatal myocardial infarction, stroke, readmission due to acute coronary syndrome, and Bleeding Academic Research Consortium (BARC) bleeding type 3 or greater, in the intention-to-treat population. This trial is registered with ClinicalTrials.gov, NCT02044250. Between March 26, 2014, and May 29, 2018, we enrolled 5530 patients. 5438 (98·3%) patients were randomly assigned to either the clopidogrel group (2710 [49·8%]) or to the aspirin group (2728 [50·2%]). Ascertainment of the primary endpoint was completed in 5338 (98·2%) patients. During 24-month follow-up, the primary outcome occurred in 152 (5·7%) patients in the clopidogrel group and 207 (7·7%) in the aspirin group (hazard ratio 0·73 [95% CI 0·59–0·90]; p=0·0035). Clopidogrel monotherapy, compared with aspirin monotherapy during the chronic maintenance period after percutaneous coronary intervention with DES significantly reduced the risk of the composite of all-cause death, non-fatal myocardial infarction, stroke, readmission due to acute coronary syndrome, and BARC bleeding type 3 or greater. In patients requiring indefinite antiplatelet monotherapy after percutaneous coronary intervention, clopidogrel monotherapy was superior to aspirin monotherapy in preventing future adverse clinical events. ChongKunDang, SamJin, HanMi, DaeWoong, and the South Korea Ministry of Health and Welfare.
Smart pH Sensing: A Self-Sensitivity Programmable Platform with Multi-Functional Charge-Trap-Flash ISFET Technology
This study presents a novel pH sensor platform utilizing charge-trap-flash-type metal oxide semiconductor field-effect transistors (CTF-type MOSFETs) for enhanced sensitivity and self-amplification. Traditional ion-sensitive field-effect transistors (ISFETs) face challenges in commercialization due to low sensitivity at room temperature, known as the Nernst limit. To overcome this limitation, we explore resistive coupling effects and CTF-type MOSFETs, allowing for flexible adjustment of the amplification ratio. The platform adopts a unique approach, employing CTF-type MOSFETs as both transducers and resistors, ensuring efficient sensitivity control. An extended-gate (EG) structure is implemented to enhance cost-effectiveness and increase the overall lifespan of the sensor platform by preventing direct contact between analytes and the transducer. The proposed pH sensor platform demonstrates effective sensitivity control at various amplification ratios. Stability and reliability are validated by investigating non-ideal effects, including hysteresis and drift. The CTF-type MOSFETs’ electrical characteristics, energy band diagrams, and programmable resistance modulation are thoroughly characterized. The results showcase remarkable stability, even under prolonged and repetitive operations, indicating the platform’s potential for accurate pH detection in diverse environments. This study contributes a robust and stable alternative for detecting micro-potential analytes, with promising applications in health management and point-of-care settings.
A Study on Improvement of Blockchain Application to Overcome Vulnerability of IoT Multiplatform Security
IoT devices are widely used in the smart home, automobile, and aerospace areas. Note, however, that recent information on thefts and hacking have given rise to many problems. The aim of this study is to overcome the security weaknesses of existing Internet of Things (IoT) devices using Blockchain technology, which is a recent issue. This technology is used in Machine-to-Machine (M2M) access payment—KYD (Know Your Device)—based on the reliability of existing IoT devices. Thus, this paper proposes a BoT (Blockchain of Things) ecosystem to overcome problems related to the hacking risk of IoT devices to be introduced, such as logistics management and history management. There are also many security vulnerabilities in the sensor multi-platform from the IoT point of view. In this paper, we propose a model that solves the security vulnerability in the sensor multi-platform by using blockchain technology on an empirical model. The color spectrum chain mentioned in this paper suggests a blockchain technique completed by using the multiple-agreement algorithm to enhance Thin-Plate Spline (TPS) performance and measure various security strengths. In conclusion, we propose a radix of the blockchain’s core algorithm to overcome the weaknesses of sensor devices such as automobile, airplane, and close-circuit television (CCTV) using blockchain technology. Because all IoT devices use wireless technology, they have a fundamental weakness over wired networks. Sensors are exposed to hacking and sensor multi-platforms are vulnerable to security by multiple channels. In addition, since IoT devices have a lot of security weaknesses we intend to show the authentication strength of security through the color spectrum chain and apply it to sensor and multi-platform using Blockchain in the future.
Preparation of Cellulose-Activated Carbon Gel with High Activated Carbon Content and Its Adsorption of Methylene Blue
Activated carbon is a useful adsorbent for the removal of pollutants from the aqueous phase. In this study, an easy method to overcome the difficulty in separating activated carbon from a solution after adsorption has been developed. Cellulose-activated carbon gels with a high activated carbon content up to 70% in the total solids were successfully prepared via the dissolution–regeneration process of cellulose using a LiBr aqueous solution. Activated carbon suspended in a cellulose solution dissolved by heating with a LiBr aqueous solution was embedded into a gel directly formed by lowering the temperature of the cellulose solution. The cellulose-activated carbon gels exhibited large specific surface areas and sufficient mechanical properties. The adsorption capacity of methylene blue onto the cellulose-activated carbon gels proportionally increased with the increasing content of activated carbon. The cellulose-activated carbon gels maintained a high adsorption capacity even after repeated adsorption–desorption cycles, demonstrating their potential as reusable adsorbents.