• ALGAE
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• 제37권2호
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• pp.149-161
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• 2022

Noctiluca scintillans is a heterotrophic dinoflagellate that causes red-colored oceans during the day (red tides) and glowing oceans at night (bioluminescence). This species feeds on diverse prey, including phytoplankton, heterotrophic protists, and eggs of metazoans. Thus, many scientists have conducted studies on the ecophysiology of this species. It is easy to cultivate N. scintillans at a scale of <1 L, but it is difficult to cultivate them at a scale of >100 L because N. scintillans cells usually stay near the surface, while prey cells stay below the surface in large water tanks. To obtain mass-cultured N. scintillans cells, we developed an automatic system for cultivating N. scintillans on a scale of 100 L. The system consisted of four tanks containing fresh nutrients, the chlorophyte Dunaliella salina as prey, N. scintillans for growth, and N. scintillans for storage, respectively. The light intensities supporting the high growth rates of D. salina and N. scintillans were 300 and 20 µmol photons m^-2 s^-1, respectively. Twenty liters of D. salina culture from the prey culture tank were transferred to the predator culture tank, and subsequently 20 L of nutrients from the nutrient tank were transferred to the prey culture tank every 2 d. When the volume of N. scintillans in the predator culture tank reached 90 L 6 d later, 70 L of the culture were transferred to the predator storage tank. To prevent N. scintillans cells from being separated from D. salina cells in the predator culture tank, the culture was mixed using an air pump, a sparger, and a stirrer. The highest abundance of N. scintillans in the predator culture tank was 45 cells mL^-1, which was more than twice the highest abundance when this dinoflagellate was cultivated manually. This automatic system supplies 100 L of N. scintillans pure culture with a high density every 10 d for diverse experiments on N. scintillans.

• Journal of Dairy Science and Biotechnology
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• 제40권4호
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• pp.163-172
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• 2022

Although the USA, Canada, and several EU countries allow raw milk cheese to be aged more than 60 days, these countries have strict standards for its aging conditions, such as temperature. Many developed countries have employed standards of identity which effectively prevent the manufacture and sale, of cheese made from unpasteurized milk (i.e., raw milk) in interstate commerce, unless such cheese has been aged for a minimum of 60 days. The microbiological safety of raw milk Camembert cheese, aged for more than 60 days, was evaluated using spiking experiments. We spiked Listeria monocytogenes into raw milk with different inoculation levels (high, medium and low). Camembert cheese was prepared from the inoculated raw milk, then aged in an incubator for up to 9 weeks (63 days). The number of cells was determined every week using the agar-plating method. Inoculated cells were completely eliminated, especially in Camembert cheese, after 60 days, and the reduction rate of cells was much faster in Camembert cheese. There were no significant differences in pH and water activity (aW) between the uninoculated cheese and the cheese samples in which Listeria monocytogenes was inoculated (p<0.05). The pH and aW of the Camembert cheese decreased throughout the storage period. In conclusion, the pathogenic bacteria used in this study did not affect the pH and aW of the Camembert cheese samples.

• 한국농공학회지
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• 제37권3_4호
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• pp.23-33
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• 1995

Geographic data which are difficult to handle by the characteristics of spatial variation and variety turned into a possibility to analyze with tlie computer-aided digital map and the use of Geographic Information System(GIS). The purpose of this study is to develop and apply a GIS application model (GISCELWAB) for the spatial simulation of surface runoff from a small watershed. This paper discribes the modeling procedure and the applicability of the cell water balance model (CELWAB) which calculates the water balance of a cell and simulates surface runoff of watershed simultaneously by the interaction of cells. The cell water balance model was developed to simulate the temporal and spatial storage depth and surface runoff of a watershed. The CELWAB model was constituted by Inflow-Outflow Calculator (JOC) which was developed to connect cell-to-cell transport mechanism automatically in this study. The CELWAB model requests detail data for each component of a cell hydrologic process. In this study, therefore, BANWOL watershed which have available field data was selected, and sensitivity for several model parameters was analyzed. The simulated results of surface runoff agreed well with the observed data for the rising phase of hydrograph except the recession phase. Each mean of relative errors for peak discharge and peak time was 0.21% and2.1 1% respectively. In sensitivity analysis of CELWAB , antecedent soil moisture condition(AMC) affected most largely the model.

• 한국수소및신에너지학회논문집
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• 제29권5호
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• pp.458-465
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• 2018

This study reports the fabrication of anion exchange membranes (AEMs) containing two kinds of functional groups: i) trimethylphosphite (TMP) and ii) trimethylamine (TMA). We carried out the synthesis of polymers to enhance thermal stability and ion conductivity. The alternative polymer was prepared using 2,2-bis(4-hydroxy-3-methylphenyl)propane and decafluorobiphenyl. The membrane was fabricated by solution casting method. The thermal stability of membranes was examined by TGA. The physiochemical properties of membranes were also investigated in terms of water uptake, swelling ratio, ion exchange capacity, and ion conductivity. The hydroxide ion conductivity of the membranes reached about 20.2 mS/cm for quaternary ammonium poly(arylene ether) (QA-PAE) containing TMA moiety and 5.1 mS/cm for quaternary phosphonium PAE (QP-PAE) containing TMP moiety at $90^{\circ}C$.

• 한국동물생명공학회지
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• 제34권3호
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• pp.190-196
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• 2019

Tight junctions are constituents of the blood-epididymis barrier that play roles in regulating the unidirectional transcellular transport of ions, water, and solutes to maintain optimal conditions for sperm maturation and storage. Claudin 1 (Cldn1) and 4 (Cldn4) are known as tight junction proteins and are expressed in the basolateral membranes as well as tight junctions in the epididymis of rodents. Here, we examined the expression and localization of Cldn1 and 4 to determine the function of these proteins in the pig epididymis. Cldn1 was highly expressed in the basolateral membrane of epithelial cells in the caput and corpus regions of the epididymis. In the cauda region, however, Cldn1 labeling was significantly decreased in the basolateral membrane of epithelial cells. In contrast, labeling indicated that Cldn4 was expressed in the basolateral membrane in the cauda region of the epididymis and was present at punctate reactive sites in the caput and corpus regions. However, in no region of the epididymis did we detect colocalization of Cldn1 and 4 with labeled ZO-1, the distribution of which is restricted to the tight junctions. Our results indicate that Cldn1 and 4 were region-specifically expressed in the pig epididymis but not present in the tight junctions of epididymal epithelium. In addition, reciprocal regulation in specific regions of the epididymis between Cldn1 and 4 may play an important role in generating an optimal luminal environment for sperm maturation and storage in the pig epididymis.

• 한국식품조리과학회지
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• 제26권6호
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• pp.831-839
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• 2010

The results of wet noodles added with 0, 1, 3, 5, and 7% freeze-dried maesangi powder demonstrate that the addition of maesangi powder up to 5% was desirable formation of noodles. The moisture contents of wet noodle 35.48~36.42%. As the added amount of maesangi powder increased, weight, volume, water absorption, and turbidity the wet noodle soup after cooking increased. Measurement of color changes between before and after cooking the wet noodles found that as the added amount of maesangi powder increased, the lightness and yellowness increased. Measurement of texture after boiling found that, hardness, chewiness and gumminess tended to increase as the amount of added maesangi powder increased whereas, springiness and cohesiveness were significantly different between the different samples. The results of the sensory evaluation showed that the 3%-added group was the best for color, flavor, and taste while the control groups had the best texture. For overall acceptability, the 3%-added group showed found the highest preference level. Measurement of the changes in total viable cells during storage at $5^{\circ}C$ for 18 days found that 6-days was the optimal storage period for the noodles from the control groups and added groups. As the storing period increased, the maesangi powder added groups showed slower propagation speed for viable cells compared to the control groups.

• Restorative Dentistry and Endodontics
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• 제39권3호
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• pp.149-154
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• 2014

Objectives: This study was performed to evaluate the cytotoxicity of four calcium silicate-based endodontic cements at different storage times after mixing. Materials and Methods: Capillary tubes were filled with Biodentine (Septodont), Calcium Enriched Mixture (CEM cement, BioniqueDent), Tech Biosealer Endo (Tech Biosealer) and ProRoot MTA (Dentsply Tulsa Dental). Empty tubes and tubes containing Dycal were used as negative and positive control groups respectively. Filled capillary tubes were kept in 0.2 mL microtubes and incubated at $37^{\circ}C$. Each material was divided into 3 groups for testing at intervals of 24 hr, 7 day and 28 day after mixing. Human monocytes were isolated from peripheral blood mononuclear cells and cocultered with 24 hr, 7 day and 28 day samples of different materials for 24 and 48 hr. Cell viability was evaluated using an MTT assay. Results: In all groups, the viability of monocytes significantly improved with increasing storage time regardless of the incubation time (p < 0.001). After 24 hr of incubation, there was no significant difference between the materials regarding monocyte viability. However, at 48 hr of incubation, ProRoot MTA and Biodentine were less cytotoxic than CEM cement and Biosealer (p < 0.01). Conclusions: Biodentine and ProRoot MTA had similar biocompatibility. Mixing ProRoot MTA with PBS in place of distilled water had no effect on its biocompatibility. Biosealer and CEM cement after 48 hr of incubation were significantly more cytotoxic to on monocyte cells compared to ProRoot MTA and Biodentine.

• 한국수소및신에너지학회논문집
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• 제33권1호
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• pp.19-27
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• 2022

A series of QPAE/TiO₂-x (x = 1, 4, 7 and 10 wt%) organic/inorganic composite membranes were prepared as electrolyte membranes for alkaline anion exchange membrane fuel cells by controlling the content of inorganic filler with quaternized poly(arylene ether) (QPAE) random copolymer. Among the prepared QPAE/TiO₂-x organic/inorganic composite membranes, the highest ionic conductivity was 26.6 mS cm^-1 at 30℃ in QPAE/TiO₂-7 composite membrane, which was improvement over the ionic conductivity value of 6.4 mS cm^-1 (at 30℃) of the pristine QPAE membrane. Furthermore, the water uptake, swelling ratio, ionic exchange capacity, and thermal property of QPAE/TiO₂-x composite membranes were improved compared to the pristine QPAE membrane. The results of these studies suggest that the fabricated QPAE/TiO₂-x composite membranes have good prospects for alkaline anion exchange membrane fuel cell applications.

• 한국환경보건학회지
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• 제28권3호
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• pp.9-18
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• 2002

This study was to observe the occurrence of heterotrophic bacteria in terms of free chlorine residuals in two different water distribution systems belong to both K and Y water treatment plant. The data analyzed in this study showed that in distribution systems(DS), the free chlorine residuals were decreased from 0.10 to 0.56 ㎎/1 for K, and 0.51 and 0.78 ㎎/l for Y The decay of free chlorine were clearly higher in both March and August than those in January. The HPC in DS were ranged from 0 to 40 CFU/ml for K,0 to 270 CFU/ml for Y, on R2A medium. In particular, Its level was relatively high at consumers' ground storage tanks, taps and point-of-end area of Y, The predominant genera found in the distribution systems were Acinetobacter, Sphingomonas (branch of Pseudomonas), Microroccus, Bacillus, Staphylococcus. The diversity of heterotrophic bacteria was increased in the end-point area. Most of them were either encapsulated cells or cocci of gram-positve. In conclusion, the point-of-end area in distribution systems showed that the longer flow distance from WTP the greater diversity and higher level of heterotrophic bacteria due to the significant decay of free chlorine residuals.

• 한국식품조리과학회지
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• 제21권5호
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• pp.717-724
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• 2005

본 연구는 품질 특성과 기능성을 가진 우리밀 국수를 개발하기 위하여 송화 분말을 물과 70% 에탄올로 추출하여 추출물의 전자공여능 및 아질산염 소거능 등의 기능성을 검토하고 송화를 첨가한 우리밀 국수의 품질특성을 검토하였다. 1. 추출물의 전자공여능은 물 및 에탄올 추출물 모두에서 농도가 증가함에 따라 전자공여능도 증가하였으며, 1,000 ppm에서 물 추출물은 67%, 에탄올 추출물은 74%로 에탄올 추출물의 전자공여능이 물 추출물 보다 높았다. 2. 추출물의 아질산염 소거능은 물 및 에탄올 추출물 모두에서 pH가 낮아짐에 따라 증가하여 pH 1.2에서 가장 높았고 동일 pH에서는 농도가 높아짐에 따라 증가하였다. 3. 송화를 첨가한 우리밀 국수 생면을 $20^{\circ}C$에서 일주일간 저장하였을 때 3% 송화첨가국수가 총균수 및 진균수는 대조구의 최대균수를 나타낸 저장일의 균수에 비해 유의적으로 낮았으나 pH 및 산도는 대조구 및 실험구간에 유의적인 차이는 없었다. 4. 송화를 첨가한 우리밀 국수의 명도(L)와 적색도(a)는 송화첨가량이 증가할수록 유의적으로 낮았으나 (p<0.05) 삶은면의 명도는 대조구와 추출물 첨가 농도에 따라 유의적인 차이는 없었다. 황색도(b)는 실험구의 농도가 증가할수록 높아져 유의적인 차이를 보였다(p<0.05). 5. 송화를 첨가한 우리밀 생면, 건면, 삶은면의 관능검사 결과 종합 기호도에서 3% 첨가구가 가장 높아 유의적인 차이를 보였다(p<0.05).