• Journal of Dairy Science and Biotechnology
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• 제40권4호
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• pp.151-162
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• 2022

Although many developed countries (USA, Canada, and several EU countries) allow raw milk cheese to be aged more than 60 days, these countries have strict standards for the aging conditions, such as temperature, of raw milk cheese. Spiking experiments were conducted with Camembert cheese made from raw milk, to assess the microbiological safety of raw milk cheese aged for more than 60 days. We spiked Escherichia coli O157:H7 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). There were no significant differences in pH and water activity (aW) between uninoculated cheese and cheese samples inoculated with E. coli O157:H7 (p<0.05). The pH and aWof the Camembert cheese decreased throughout the storage period. In conclusion, E. coli O157:H7 did not affect the pH and aW of the cheese samples. Cell counts were conducted 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.

• 환경생물
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• 제41권2호
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• pp.167-178
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• 2023

Large amounts of waste and wastewater from aquaculture have negatively impacted ecosystems. Among them, shrimp aquaculture wastewater contains large amounts of nitrogen contaminants derived from feed residues in an aerobic environment. This study isolated candidate strains from adult rockworms to treat shrimp aquaculture wastewater (SAW) in an aerobic environment. Among 87 strains isolated, 25 grew well at the same temperature as the shrimp aquaculture with excellent polymer degradation ability (>0.5 cm clear zone). Six isolates (strains AL1, AL4, AL5, AL6, LA10, and PR15) were finally selected after combining strains with excellent polymer degradation ability without antagonism. 16S rRNA sequencing analysis revealed that strains AL1, AL4, AL5, AL6, LA10, and PR15 were closely related to Bacillus paramycoides, Bacillus pumilus, Stenotrophomonas rhizophila, Bacillus paranthracis, Bacillus paranthracis, and Micrococcus luteus, respectively. When these six isolates were applied to SAW, they reached a maximum cell viability of 2.06×10⁵ CFU mL^-1. Their chemical oxygen demand (COD_Cr) and total nitrogen(TN) removal rates for 12h were 51.0% and 44.6%, respectively, when the COD_Cr/TN ratio was approximately 10.0. Considering these removal rates achieved in this study under batch conditions, these six isolates could be used for aerobic denitrification. Consequently, these six isolates from rockworms are good candidates that can be applied to the field of aquaculture wastewater treatment.

• Journal of Medicine and Life Science
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• 제19권2호
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• pp.46-56
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• 2022

The incidence of fever complicating percutaneous coronary intervention (PCI) is rare. However, little is known regarding the cause of fever after PCI. Therefore, this study aimed to determine the clinical characteristics of patients with acute myocardial infarction (AMI), with or without fever, after PCI. We enrolled a total of 926 AMI patients who underwent PCI. Body temperature (BT) was measured every 4 hours or 8 hours for 5 days after PCI. Patients were divided into two groups according to BT as follows: BT<37.7℃ (no-fever group) and BT ≥37.7℃ (fever group). The 2 years clinical outcomes were compared subsequently. Fever after PCI was associated with higher incidence of major adverse cardiac events (MACE) (hazard ratio [HR], 1.56; 95% confidence interval [CI], 1.07-2.28; P=0.021), all-cause death (HR, 2.32; 95% CI, 1.18-4.45; P=0.014), cardiac death (CD) (HR, 2.57; 95% CI, 1.02-6.76; P=0.049), and any revascularization (HR, 1.69; 95% CI, 1.02-2.81; P=0.044) than without fever. In women, prior chronic kidney disease, lower left ventricular (LV) ejection fraction, higher LV wall motion score index, white blood cell count, peak creatine kinase-myocardial band level, and longer PCI duration were associated with fever after PCI. Procedures such as an intra-aortic balloon pump, extracorporeal membrane oxygenation, continuous renal replacement therapy, central and arterial line insertion, and cardiopulmonary resuscitation were related to fever after PCI. Fever after PCI in patients with AMI was associated with a higher incidence of MACE, all-cause death, CD, and any revascularization at the 2 years mark than in those without fever.

• Animal Bioscience
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• 제36권8호
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• pp.1285-1292
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• 2023

Objective: The objective of this study was to develop a novel endolysin (PanLys.1) for the specific killing of the ruminal hyper-ammonia-producing bacterium Peptostreptococcus anaerobius (P. anaerobius). Methods: Whole genome sequences of P. anaerobius strains and related bacteriophages were collected from the National Center for Biotechnology Information database, and the candidate gene for PanLys.1 was isolated based on amino acid sequences and conserved domain database (CDD) analysis. The gene was overexpressed using a pET system in Escherichia coli BL21 (DE3). The lytic activity of PanLys.1 was evaluated under various conditions (dosage, pH, temperature, NaCl, and metal ions) to determine the optimal lytic activity conditions. Finally, the killing activity of PanLys.1 against P. anaerobius was confirmed using an in vitro rumen fermentation system. Results: CDD analysis showed that PanLys.1 has a modular design with a catalytic domain, amidase-2, at the N-terminal, and a cell wall binding domain, from the CW-7 superfamily, at the C-terminal. The lytic activity of PanLys.1 against P. anaerobius was the highest at pH 8.0 (p<0.05) and was maintained at 37℃ to 45℃, and 0 to 250 mM NaCl. The activity of PanLys.1 significantly decreased (p<0.05) after Mn²⁺ or Zn²⁺ treatment. The relative abundance of P. anaerobius did not decrease after administration PanLys.1 under in vitro rumen conditions. Conclusion: The application of PanLys.1 to modulate P. anaerobius in the rumen might not be feasible because its lytic activity was not observed in in vitro rumen system.

• Current Photovoltaic Research
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• 제11권2호
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• pp.44-48
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• 2023

In heterojunction technology (HJT) solar cells, low-temperature curing paste is used because the passivation layer deteriorates at high temperatures of 200℃ or higher. However, manufacturing HJT photovoltaic (PV) modules is challenging due to the weak peel strength between busbar electrodes and cells after soldering process. For this issue, the electrode thicknesses of the busbars of the HJT solar cell were analyzed, and the peel strengths between electrodes and wires were measured after soldering using an infrared (IR) lamp. As a result, the electrodes printed by the screen printing method had a difference in thickness due to screen mask. Also, as the thickness of the electrode increased, the peel strength of the wire increased.

• 한국식생활문화학회지
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• 제24권6호
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• pp.749-755
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• 2009

We investigated the chemical components of red onion powder dried using the low temperature vacuum method and the inhibitory effects of solvent extracts of the dried red onion powder on the growth of HT-1080 human fibrosarcoma and HT-29 human colon cancer cells and $H_2O_2$-induced oxidative stress. The moisture content of the dried red onion powder was 17.95%, while the vitamin C content was 96 mg/100 g and the total phenols content was 39.1 mg/mL. The inhibitory effects of acetone with methylene chloride (A+M) and methanol (MeOH) extracts of the red onion powder on the growth of HT-1080 and HT-29 cancer cells increased in a dose dependent manner (p<0.05). The inhibitory effect was greater on the growth of HT-29 cells, while the A+M extracts had a higher inhibitory effect than the MeOH extracts. Treatment with the hexane, 85% aq. methanol, butanol and water fractions of the extract led to significant inhibition of the growth of both cancer cell lines (p<0.05). Among the fractions, the hexane and 85% aq. methanol fractions showed a greater inhibitory effect. To determine the protective effect on $H_2O_2$-induced oxidative stress, a DCFH-DA (dichlorodihydrofluorescin diacetate) assay was conducted. All fractions, including the crude extracts of dried red onion, appeared to lead to a significant reduction in the levels of intracellular reactive oxygen species (ROS), and these reductions occurred in a dose dependent fashion (p<0.05). Among the fractions, the 85% methanol fraction showed the greatest protective effect on the production of lipid peroxides.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2022년도 추계학술대회
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• pp.221-221
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• 2022

Chromosome breakage occurred by DNA methylation inhibitor. Zebularine is known as DNA methylation inhibitor and suitable for water solubility among different DNA methylation inhibitors as 5-Azacytidine and 5-aza-2'-deoxycytidine. We used zebularine as mutagen according to different methods by roots absorption and seed imbibition. After zebularine treatment, DNA methylation inhibitor, we observed mitotic chromosome behavior what is different according to two different treatment methods. First, seed imbibition treatment in 1,000 μM of zebularine solution for 72 hours in dark conditions. The second treatment to seedlings of Keumkang was also treated in 1,000 μM of zebularine solution for 72 hours after germination. Root and shoot showed different elongations in each treatment. Root absorption treatment(3.01±0.48, 2.00±0.26) showed the shortest elongation in root and shoot than control(8.16±0.61, 4.03±0.48) and seed imbibition treatment(4.33±0.80, 2.48±0.36). It can be explained root tip meristematic cell activity was damaged by DNA methylation inhibitor. Primary root tips were collected in DW for 24 hours at low temperature(0℃) and fixed in fixation solution for 3 days to chromosome observation in mitosis. Mitotic index, chromosome structure and chromosome aberration were observed by phase-contrast microscope. Mitotic index of the control(0.29) showed twice mitotic cells as the treated groups(imbibition 0.15, absorption 0.14). Observation of chromosomes showed some short chromosomes and loosen chromosomes affected by zebularine. It is considered because of zebularine damage DNA in mitosis. We observed "gap by chromosome breakage" in chromosomes that have loose parts between centromere and telomere. It seems demethylation of zebularine occurs chromosome breakage.

• 광물과 암석
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• 제36권4호
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• pp.337-343
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• 2023

감람석은 철감람석과 마그네슘감람석의 완전고용체로서 암석형 행성, 운석, 소행성, 행성간 먼지 등에 풍부하게 함유되어 있다. 감람석은 조성범위가 매우 넓기 때문에 감람석 함유 시료의 광물정량분석을 위해서는 다양한 조성의 감람석 표준물질을 구비해야 한다. 감람석 표준물질을 전기로와 스테인리스강관을 이용하여 1000~1100 ℃ 범위의 온도에서 합성하였다. 엑스선회절분석에 의하면 시료에 따라 합성불순물과 미반응물이 있으나 전반적으로 전조성 범위를 포함하는 감람석이 합성되었다. 합성 감람석들은 출발물질의 철감람석 몰비에 비례하여 단위포 치수가 선형으로 증가하는 경향을 보였으며, 회절강도도 자연산 감람석과 부합하였다. 그러나 철 함량이 높은 합성 감람석에서 불순물 함량이 증가하는 경향이 있어 아직 모든 합성 감람석을 표준물질로 사용할 수 없으며, 출발물질의 고순도화, 반응시간 및 온도 조절 등의 합성과정 개선이 필요하다.

• Current Photovoltaic Research
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• 제12권1호
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• pp.1-5
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• 2024

Perovskite solar cells have exhibited a remarkable increase in efficiency from an initial 3.8% to 26.1%, marking a significant advancement. However, challenges persist in the commercialization of perovskite solar cells due to their low stability with respect to humidity, light exposure, and temperature. Moreover, the instability of the organic charge transport layer underscores the need for exploring inorganic alternatives. In the manufacturing process of the perovskite solar cells' oxide charge transport layer, ultraviolet-ozone (UVO) treatment is commonly applied to enhance the wettability of the perovskite solution. The UVO treatment on metal oxides has proven effective in suppressing surface oxygen vacancies and removing surface organic contaminants. This study focused on the characterization of nickel oxide as the hole transport material in perovskite solar cells, specifically investigating the impact of UVO treatment on film properties. Through this analysis, changes induced by the UVO treatment were observed, and consequent alterations in the device characteristics were identified.

• 한국지반환경공학회 논문집
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• 제25권7호
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• pp.21-27
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• 2024

동상은 동토지반의 중요한 공학적 특성 중 하나로, 겨울철에 국내에서는 동상으로 인한 다양한 피해가 발생한다. 미국과 일본은 동토지역을 포함하고 있어 동상에 대한 연구가 활발히 이루어졌으며, 표준화된 실험법을 보유하고 있다. 특히, 일본 동상 실험법은 시료 준비와 실험 과정이 비교적 간단하다는 장점이 있다. 그러나 동상 실험 결과의 공학적 해석이 모호하며, 동상 민감성 판정 기준이 제시되지 않아 실제 활용에 문제가 있다. 본 논문에서는 모래-실트 혼합토를 대상으로 일본 동상 실험법에 따라 온도제어형 셀을 활용한 실내실험을 수행하고, 동상속도 산정 과정을 면밀히 분석하였다. 더불어, 일본 동상 실험법으로 산정된 동상속도가 미국에서 제시한 동상 민감성 판정 기준에 적용 가능한지 검토하였다.