• Journal of Korean Society of Water and Wastewater
• /
• v.35 no.1
• /
• pp.63-69
• /
• 2021

Microalgae are primary producers of aquatic ecosystems, securing biodiversity and health of the ecosystem and contributing to reducing the impact of climate change through carbon dioxide fixation. Also, they are useful biomass that can be used as biological resources for producing valuable industrial products. However, harvesting process, which is the separation of microalgal biomass from mixed liquor, is an important bottleneck in use of valorization of microalgae as a bioresource accounting for 20 to 30% of the total production cost. This study investigates the applicability of sewage sludge-derived extracellular polymeric substance (EPS) as bioflucculant for harvesting microalgae. We compared the flocculation characteristics of microalgae using EPSs extracted from sewage sludge by three methods. The flocculation efficiency of microalgae is closely related to the carbohydrate and protein concentrations of EPS. Heat-extracted EPS contains the highest carbohydrate and protein concentrations and can be a best-suited bioflocculant for microalgae recovery with 87.2% flocculation efficiency. Injection of bioflocculant improved the flocculation efficiency of all three different algal strains, Chlorella Vulgaris, Chlamydomonas Asymmetrica, Scenedesmus sp., however the improvement was more significant when it was used for flocculation of Chlamydomonas Asymmetrica with flagella.

• Food Science and Industry
• /
• v.50 no.1
• /
• pp.67-73
• /
• 2017

Control of food pathogens is critical in food safety field. Norovirus is one of the major causes of gastroenteritis and food poisoning worldwide, however, currently, there is not a vaccine or a specific drug available for its treatment. There are several methods to inactivate norovirus during food processing by chemical and physical treatments, however, the use of natural substance has been suggested as an optional strategy due to their safety and consumer preference. In this study supported by Ministry of Food and Drug Safety in Korea, we identified novel plant-derived substances with significant anti-norovirus activities. The aim of this project was to determine the antiviral activity of a wide range of natural substances, including plant-derived extracts and essential oils, using a norovirus surrogate system, human norovirus replicon-bearing cells, and mouse in vivo experiments. During the activity screening test, we identified novel anti-norovirus substances or oils using plaque assay with MNV-1. Six selected substances were formulated into an optimum mixture and used as an ingredient for salad sauce of which anti-novovirus activity was confirmed(pending for patent and paper submission). The potential application of selected natural substances as a metal surface sanitizer was also tested. Interestingly, the mixture of selected natural compounds showed a significant inhibitory effect against norovirus. These results suggest that these substances may be used as food ingredient with anti-norovirus antivity or components for surface sanitizers to prevent norovirus contamination.

• Journal of Industrial Convergence
• /
• v.21 no.2
• /
• pp.79-84
• /
• 2023

This study was analyzed based on 1051 analyzes of questionnaires in order to examine the status and perception of abused drugs according to the gender of the young people entering the adult group from the adolescents. The gender of the young people who participated in the survey was 686 males and 365 females, and the types of abused drugs and their perceptions of harmful effects of narcotics and abused drugs were analyzed according to gender. As a result of the study, the experience of using alcohol, tobacco, appetite suppressants, sedatives, and opioid analgesics was statistically significant according to gender. Among the harmful effects of narcotic drugs and drugs of abuse, significant results were shown on the recognition of risks, induced problems, and sympathy for risks. As for the desirable way to improve the problem of narcotics and substance abuse, 257 women (68.2%) of women wanted publicity (enlightenment) activities, and about effective education for preventing narcotics and substance abuse, 379 men (54.2%) of men %) appeared as online online education. It is considered that proper education and publicity about drug use is necessary in the reality that drug addiction among young people due to drug abuse is increasing.

• Preventive Nutrition and Food Science
• /
• v.10 no.1
• /
• pp.95-102
• /
• 2005

The term pharmacognosy as applied to a constituent scientific discipline of Korean Medical Food (KMF) has been in use for nearly several years, and it refers to studies on the pharmacological properties of natural products foods. During the last half of the 20th century, pharmacognosy for KMF evolved from being a descriptive botanical subject to one having a more chemical and biological focus. At the beginning of the 21st century, teaching pharmacognosy for KMF teaching in academic culinary arts and natural healing institutions has been given new relevance as a result of the explosive growth in the use of herbal foods (health foods) in modern KMF practice. In turn, pharmacognosy for KMF research areas are continuing to expand, and now include aspects of cellular and molecular biology in relation to natural products, ethnobotany and phytotherapy, in addition to the more traditional analytical method development and phytochemistry. Examples are provided in this review of promising bioactive compounds obtained in two multidisciplinary natural product KMF development and discovery projects, aimed at the elucidation of new plant-derived cancer chemotherapeutic agents and novel cancer chemopreventives, respectively. The systematic study of KMF offers pharmacognosy groups an attractive new area of research, ranging from investigating the biologically active principles of KMF and their mode of action and potential active substance interactions, to sanitary and quality control, and involvement in clinical trials.

• Proceedings of the Korean Vacuum Society Conference
• /
• 2013.02a
• /
• pp.627-627
• /
• 2013

Recently, most studies concerning inorganic CdSe/ZnS quantum dot (QD)-polymer hybrid LEDs have been concentrated on the structure with multiple layers [1,2]. The QD LEDs used almost CdSe materials for color reproduction such as blue, green and red from the light source until current. However, since Cd is one of six substances banned by the Restriction on Hazardous Substances (RoHS) directive and classified into a hazardous substance for utilization and commercialization as well as for use in life, it was reported that the use of CdSe is not suitable to fabricate a photoelectronic device. In this work, we demonstrate a novel, simple and facile technique for the synthesis of ZnO-graphene quasi-core.shell quantum dots utilizing graphene nanodot in order to overcome Cd material including RoHS materials. Also, We investigate the optical and structural properties of the quantum dots using a number of techniques. In result, At the applied bias 10 V, the device produced bluish-white color of the maximum brightness 1118 cd/$m^2$ with CIE coordinates (0.31, 0.26) at the bias 10 V.

• KIEAE Journal
• /
• v.8 no.1
• /
• pp.81-86
• /
• 2008

Due to the recent environmental problems, lots of studies on the solutions to reduce the environmental pollutions are on the way. In the field of construction, concrete that we are currently consuming approximately 1 ton each year is the most common and cheap building material. We must cut down on this preoccupied use of this material and develop an alternative material as recommended by the late environmental standards. In this regard, this study propose the 'yellow soil' as the main substance that composes the final state, 'yellow soil concrete'. This study also aims to analyze the physical and chemical performances of this concrete mixed with the yellow soil by comparing it with the cement and assesses the possibility of its application to the cement. The results of the experiment shows that, assuming the solidity of the cement concrete to be around $210kg/cm^2$ (20.58MPa), the solidity of the yellow soil combined material may be around 45%~55% in terms of the range of W/B use, 200 to 400 in the per unit fission amount and less than 2% in the addition proportion of admixing agents. But the scope of the optimal concoction amount of the yellow soil concrete should better be limited as following. 40% to 50% in W/B, 300 to 400 in the per unit fission amount and less than 2% in the addition of admixing agents.

• Proceedings of the Korean Geotechical Society Conference
• /
• 2008.10a
• /
• pp.1673-1677
• /
• 2008

A method of construction with a basis treatment that uses a latticed bamboo mat puts bamboo's peculiarity and bamboo mat's bending substance to use, and a latticed bamboo mat equally distributes to embankment loading in a basis ground. Therefore it prevents ground destruction by an ill-balanced load and an irregular ground subsidence, and it makes safety system. This investigation make progress a soil box model by a dredged reclamation ground of west and south sea at domestic area, and make a comparative study and analyze the strengthening effect based on a grid size of a bamboo-mat and ground failure that it will use in the field.

• Journal of Powder Materials
• /
• v.27 no.6
• /
• pp.458-463
• /
• 2020

Hispidin is a secondary metabolite found in numerous medicinal mushrooms that has attracted significant attention, owing to its distinct biological effects, including antioxidant, anti-inflammatory, antitumor, and cytoprotective properties. Experiments are being carried out to study the interaction of detonation nanodiamonds (DNDs) with synthetic and natural hispidin sourced from extracts of Pholiota sp. fungus. The bioluminescence method is used to determine the adsorption/desorption properties of DNDs toward hispidin. It is found that hispidin forms strong conjugates with DNDs, and the use of various eluents does not result in a significant release of the adsorbed hispidin molecules. DND-bovine serum albumin (BSA) complex, where DNDs serve as a carrier for the protein and the latter acts as a hispidin sorbent, has been developed and applied in hispidin adsorption/desorption tests. The results support the use of the DNDs as a carrier for hispidin in medical applications. They also advocate the application of the DND-BSA complex for isolating the substance from fungal extracts.

• International conference on construction engineering and project management
• /
• 2022.06a
• /
• pp.295-303
• /
• 2022

Residential heating systems in South Korea are largely based on the use of ondol pipelines. Heat is transferred to the floor by passing hot water through a metal or plastic pipe buried within the concrete of the floor. Consequently, it is difficult to clean the inside of these pipes after installation. Over time, foreign substances such as scale accumulate in the pipe when the ondol heating method is used for an extended period. Therefore, in the past, pipes were cleaned by removing foreign substances attached to the inside surfaces of the pipes using high-pressure water or by disassembling the pipes and removing foreign substances with chemical agents. Recently, a method for removing foreign substances through the cavitation effect of ultrasound has been proposed. This idea might lead to the development of new technologies for cleaning pipe interiors. Consequently, this study investigated the use of ultrasound to clean pipes embedded in concrete. In this study, devices that generated ultrasonic waves with various frequencies and directions were prepared. After preparing arbitrarily contaminated pipes, the appropriate frequency, output strength, and output direction for each foreign substance were determined through repeated experiments. The results of this experiment could provide important information for future methods of cleaning the interior of ondol piping systems.

• Microbiology and Biotechnology Letters
• /
• v.37 no.2
• /
• pp.125-132
• /
• 2009

In order to develop probiotics which may be a viable alternative of antibiotic use in pig industry, five bacterial strains (Lactobacillus sp. HN 52, 92, 98, 235 and AP 116) possessing antimicrobial properties were selected from 500 strains isolates of pig intestines. The bacteriocin produced by Lactobacillus sp. HN 235 displayed a relative broad spectrum of inhibitory activity against all Enterococcus strains, Pseudomonas aeruginosa, Listeria monocytogenes and Clostridium perfringens using the spot-on-lawn method. The production of antimicrobial substance started in the middle of the exponential growth phase, reached maximum levels (6,400 AU/mL) in the stationary phase, and then declined. Bacteriocin activity remained unchanged after 30 min of heat treatment at $95^{\circ}C$ and stable from pH 2.0 to 10 for 1 h, or exposure to organic solvents; however, it diminished after treatment with proteolytic enzymes. The molecular weight of the bacteriocin was about 5 kDa according to a tricine SDS-PAGE analysis.