• Korean Chemical Engineering Research
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• 제57권5호
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• pp.714-722
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• 2019

산 염기성질이 다양하게 존재하는 담체($SiO_2-Y_2O_3$, $Al_2O_3$, $SiO_2-ZrO_2$, $SiO_2$, $TiO_2$, MgO) 상에 17 wt% Ni을 고정한 상태에서 함침법을 사용하여 촉매를 제조하여 수소 존재 하에 에탄올과 암모니아의 환원성 아민화 반응에 대한 촉매활성을 비교 평가하였다. 반응 전후에 있어 사용된 촉매는 X-선 회절, 질소 흡착, 에탄올-승온탈착(EtOH-TPD), 이소프로판올-승온탈착(IPA-TPD), 수소 화학흡착을 사용하여 특성분석을 수행하였다. pH 9.5 이상에서 침전법을 사용하여 $ZrO_2$와 $Y_2O_3$ 담체 제조 시 파이렉스 반응기에서 미량의 Si 용융으로 인해 $SiO_2-ZrO_2$와 $SiO_2-Y_2O_3$ 복합 산화물이 각각 생성되었다. 사용된 촉매 중에서 $Ni/SiO_2-Y_2O_3$ 촉매가 가장 좋은 활성을 보였으며 이는 높은 니켈 분산도와 EtOH-TPD와 IPA-TPD에서의 낮은 탈착온도 등과 밀접한 관련이 있었다. Ni/MgO 촉매상에서의 낮은 촉매 활성은 NiO-MgO 고형물 형성에 기인한 것으로 보이며, $Ni/TiO_2$ 경우에서는 담체-금속 간의 강한 상호 작용으로 인해 낮은 니켈 금속 상 존재로 인해 반응성이 낮게 나왔다. $TiO_2$와 MgO 이외의 담체를 사용한 경우에 있어서 유사한 에탄올 전환율에서의 에틸아민류와 아세토니트릴 선택도는 큰 차이를 보이지 않았다.

• Asian-Australasian Journal of Animal Sciences
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• 제32권10호
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• pp.1528-1539
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• 2019

Objective: To evaluate the effects on microbial diversity and biochemical parameters of gradually increasing temperatures, from $5^{\circ}C$ to $25^{\circ}C$ on corn silage which was previously fermented at ambient or low temperature. Methods: Whole-plant corn silage was fermented in vacuum bag mini-silos at either $10^{\circ}C$ or $20^{\circ}C$ for two months and stored at $5^{\circ}C$ for two months. The mini-silos were then subjected to additional incubation from $5^{\circ}C$ to $25^{\circ}C$ in $5^{\circ}C$ increments. Bacterial and fungal diversity was assessed by polymerase chain reaction-denaturing gradient gel electrophoresis (PCR-DGGE) profiling and biochemical analysis from mini-silos collected at each temperature. Results: A temperature of $10^{\circ}C$ during fermentation restricted silage fermentation compared to fermentation temperature of $20^{\circ}C$. As storage temperature increased from $5^{\circ}C$ to $25^{\circ}C$, little changes occurred in silages fermented at $20^{\circ}C$, in terms of most biochemical parameters as well as bacterial and fungal populations. However, a high number of enterobacteria and yeasts (4 to $5\;log_{10}$ colony forming unit/g fresh materials) were detected at $15^{\circ}C$ and above. PCR-DGGE profile showed that Candida humilis predominated the fungi flora. For silage fermented at $10^{\circ}C$, no significant changes were observed in most silage characteristics when temperature was increased from $5^{\circ}C$ to $20^{\circ}C$. However, above $20^{\circ}C$, silage fermentation resumed as observed from the significantly increased number of lactic acid bacteria colonies, acetic acid content, and the rapid decline in pH and water-soluble carbohydrates concentration. DGGE results showed that Lactobacillus buchneri started to dominate the bacterial flora as temperature increased from $20^{\circ}C$ to $25^{\circ}C$. Conclusion: Temperature during fermentation as well as temperature during storage modulates microorganism population development and fermentation patterns. Silage fermented at $20^{\circ}C$ indicated that these silages should have lower aerobic stability at opening because of better survival of yeasts and enterobacteria.

• 공업화학
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• 제33권2호
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• pp.151-158
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• 2022

본 논문은 활성탄에 의해 작용기가 다른 말라카이트 그린(MG), 다이렉트 레드 81 (DR 81) 및 티오플라빈 S (TS)의 흡착에 대한 파라미터 특성(PH 효과, 등온선, 동역학 및 열역학 파라미터) 및 염료의 경쟁 흡착에 대해 조사하였다. Langmuir, Freundlich 및 Temkin 등온선 모델을 사용하여 염료의 흡착 메커니즘 및 활성탄에 의한 흡착 처리의 적합성을 평가했다. Langmuir 무차원 분리 계수 값은 활성탄에 의한 세 가지 염료의 흡착 처리가 효과적인 방법임을 나타내었다. 활성탄에 대한 세 가지 염료의 흡착 메커니즘은 Temkin 식에서 계산된 흡착열로부터 물리 흡착임을 확인하였다. 세 가지 염료의 흡착 동역학은 유사 2차 모델에 가까웠으며 잘 일치함을 보여주었다. 활성탄에 의한 세 가지 염료의 흡착 과정의 속도 지배 단계는 입자내 확산이었다. 양의 엔탈피와 엔트로피 변화는 각각 흡열 반응과 고액계면에서 흡착에 의한 무질서도가 증가함을 나타내었다. 세 가지 염료의 음의 Gibbs 자유 에너지 값은 온도가 증가함에 따라 자발성이 높아지는 것을 나타냈다. 삼성분 경쟁흡착에서 흡착능력이 높은 MG는 혼합용액에서 DR 81과 TS에 의해 약간의 방해를 받았으나, 흡착능력이 낮은 DR 81과 TS는 흡착력이 좋은 MG의 영향을 받아 흡착률이 크게 증가하였다.

• Advances in nano research
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• 제13권6호
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• pp.575-585
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• 2022

Due to its biofilm formation and colonization of the osteocyte-lacuno canalicular network (OLCN), Staphylococcus aureus (S.aureus) implant-associated bone infection (SIABI) is difficult to cure thoroughly, and may occur recurrently subsequently after a long period dormant. It is essential to explore an alternative therapeutic strategy that can eradicate the pathogens in the infected foci. To address this, the polymethylmethacrylate (PMMA) bone cement and Fe3O4 nanoparticles compound cylinder were developed as implants based on their size and mechanical properties for the alternative magnetic field (AMF) induced thermal ablation, The PMMA mixed with optimized 2% Fe₃O₄ nanoparticles showed an excellent antibacterial efficacy in vitro. It was evaluated by the CFU, CT scan and histopathological staining on a rabbit 1-stage transtibial screw model. The results showed that on week 7, the CFU of infected soft tissue and implants, and the white blood cells (WBCs) of the PMMA+2% Fe₃O₄+AMF group decreased significantly from their controls (p<0.05). PMMA+2% Fe₃O₄+AMF group did not observe bone resorption, periosteal reaction, and infectious reactive bone formation by CT images. Further histopathological H&E and Gram Staining confirmed there was no obvious inflammatory cell infiltration, neither pathogens residue nor noticeably burn damage around the infected screw channel in the PMMA+2% Fe₃O₄+AMF group. Further investigation of nanoparticle distributions in bone marrow medullary and vital organs of heart, liver, spleen, lung, and kidney. There were no significantly extra Fe₃O₄ nanoparticles were observed in the medullary cavity and all vital organs either. In the current study, PMMA+2% Fe₃O₄+AMF shows promising therapeutic potential for SIABI by providing excellent mechanical support, and promising efficacy of eradicating the residual pathogenic bacteria in bone infected lesions.

• 대한본초학회지
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• 제28권3호
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• pp.53-60
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• 2013

Objectives : DojukSan is known to be effective for treating a urinary diseases and stomatitis. However, there has been a lack of studies regarding the effects of Dojuksan on the inflammatory activities and effector inflammatory disease mechanism about macrophage before is not known. To elucidate the molecular mechanisms of Dojuksan water extract (DJS) on pharmacological and biochemical actions in inflammation, we examined the effect of DJS on pro-inflammatory mediators in lipopolysaccharide (LPS)-stimulated macrophages. Methods : In the present study, pro-inflammatory cytokine production was determined by performing enzyme-linked immunosorbent assay, reverse transcription polymerase chain reaction, and western blot analysis to measure the activation of MAPKs. Cells were treated with 200 ng/mL of LPS 1 h prior to the addition of DJS. Cell viability was measured by MTS assay. The investigation focused on whether DJS inhibited nitric oxide (NO) and prostaglandin E2 ($PGE_2$) productions, as well as the expressions of inducible NO synthase (iNOS), cyclooxygenase-2 (COX-2), interleukin-6 (IL-6) and mitogen-activated protein kinases (MAPKs) in LPS-stimulated RAW 264.7 cells. Results : We found that DJS inhibited LPS-induced NO, $PGE_2$ and IL-6 productions as well as the expressions of iNOS and COX-2. Furthermore, DJS suppressed the LPS-induced phosphorylation of p38 MAPK and c-Jun NH2-protein kinase (JNK). Conclusions : These results suggest that DJS has inhibitory effects on LPS-induced $PGE_2$, NO, and IL-6 production, as well as the expressions of iNOS and COX-2 in the murine macrophage. These inhibitory effects occur through blockades on the MAPKs phosphorylation.

• 대한본초학회지
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• 제28권5호
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• pp.7-11
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• 2013

Objectives : Seungmagalgeun-tang (SMGGT) is traditional medicine widely used for inflammatory disease and flu. But SMGGT exhibits potent anti-inflammatory activity with an unknown mechanism. To elucidate the molecular mechanisms of SMGGT water extract on pharmacological and biochemical actions in inflammation, we examined the effect of SMGGT on pro-inflammatory mediators in Phorbol-12-myristate-13-acetate (PMA)+A23187-stimulated mast cells. Methods : In the present study, pro-inflammatory cytokine production was determined by performing enzyme-linked immunosorbent assay (ELISA), reverse transcription polymerase chain reaction (RT-PCR), and western blot analysis to measure the activation of MAPKs. Cells were treated with SMGGT 1 h prior to the addition of 50 nM of PMA and $1{\mu}M$ of A23187. Cell viability was measured by MTS assay. The investigation focused on whether SMGGT inhibited the expressions of interleukin-6 (IL-6), interleukin-8 (IL-8) and mitogen-activated protein kinases (MAPKs) in PMA+A23187-stimulated mast cells. Results : SMGGT has no cytotoxicity at examined concentration (100, 250, and $500{\mu}g/ml$). Also, gene expression of IL-6 and IL-8 in HMC-1 cells stimulated by PMA+A23187 was down regulated by SMGGT. Furthermore, SMGGT suppressed the PMA+A23187-induced phosphorylation of extracellular signal-regulated kinase (ERK) and c-jun N-terminal Kinase(JNK). But, SMGGT could not regulate phosphorylation of p38 MAPK. Conclusions : These results suggest that SMGGT has inhibitory effects on PMA+A23187-induced IL-6 and IL-8 production. These inhibitory effects occur through blockades on the phosphorylation of ERK and JNK.

• 한국동물위생학회지
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• 제45권2호
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• pp.71-77
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• 2022

African swine fever (ASF) is a fatal viral disease in pigs, with a short incubation period and causing immediate death. Few studies exist on the Asian epidemic ASF virus (ASFV) challenge in older pigs, including growing and fattening pigs and sows. We aimed to investigate clinical outcomes, pathomorphological lesions, and viral distribution in organs of 3-month-old growing pigs that were inoculated with the ASFV isolated in Vietnam. The clinical outcomes were recorded daily, and the dead or euthanized pigs immediately underwent necropsy. Viral loads were determined in 10 major organs using quantitative polymerase chain reaction. The average incubation period in growing pigs was more delayed (5.2±0.9 dpi) than that in weaned pigs, and the clinical signs were milder in growing pigs than in weaned pigs. The digestive and respiratory clinical signs in growing pigs showed at the end period of life, but these were observed at an early stage of infection in weaned pigs. The pathomorphological features were severe and nonspecific with hemorrhagic lesions in various organs. The viral loads in organs from growing pigs were higher than those from piglets, and the number of viral copies was related to gross lesions in the tonsil and intestine. In the absence of vaccines against ASF, early clinical detection is important for preventing the spread of the virus. Our findings elucidated that the clinical signs and gross lesions in growing pigs differed from those in weaned pigs, which provide valuable information for diagnosis of pigs with suspected ASF infection.

• 자원리싸이클링
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• 제32권3호
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• pp.9-17
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• 2023

폐리튬인산철 전지의 양극재로부터 리튬을 효율적으로 회수하기 위하여 활발하게 연구 중이며, 이는 리튬 자원의 지역 편재성 및 가격 변동성을 해소하고 환경오염 문제를 해결할 수 있다. 폐리튬인산철 전지로부터 리튬을 침출 및 회수하기 위하여 동형치환 침출 공정을 사용하였다. 상대적으로 저렴한 염화철 에칭액을 침출제로 사용하여 LFP의 Fe²⁺를 동형 치환하여 리튬을 침출하였다. 또한 추가적인 첨가제 및 추출제 없이 염화철 에칭액만을 사용하였으며, 염화철 에칭액을 LFP 이론적 몰 비 대비 0.7배, 1.0배, 1.3배, 그리고 1.6배로 하여 리튬의 침출율을 비교하였다. LFP 몰 비 대비 1.3배의 조건에서 약 98%로 가장 높은 리튬 침출율을 보였고 이후 침출액은 NaOH를 투입하여 pH 조절을 통하여 철을 제거하였다. 철이 제거된 용액으로부터 탄산리튬을 합성하였고, 그 분말 특성을 확인하였다.

• 현장농수산연구지
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• 제18권1호
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• pp.63-70
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• 2016

산채의 일종으로 현재 임업농가에서 활발히 재배되고 있는 눈개승마와 어수리의 수증기압차(vapor pressure deficit; VPD)에 따른 순광합성 속도 등 생리반응을 조사하여 효율적인 생산과 재배관리를 위한 기초자료를 제공하고자 하였다. 건조한 High-VPD 환경에서 눈개승마가 어수리에 비해 증산량을 줄이면서 수분이용효율을 높이는 기작을 통해 높은 순광합성 속도를 유지하는 것을 알 수 있었으며, 어수리에 비해 눈개승마는 엽의 수분 퍼텐셜의 감소가 비교적 크지 않고, 엽의 수분 불포화도 역시 큰 변화가 없는 것으로 보아 건조한 대기 환경에 따른 수분스트레스의 적응력이 비교적 양호한 종임을 알 수 있었다. 어수리는 VPD가 3.0kPa 이상으로 높게 나타나는 건조한 대기상태가 되면 순광합성 속도의 감소가 뚜렷히 나타나고 수분 퍼텐셜의 급속한 저하 및 엽의 수분 불포화도가 10배 이상 높게 나타나 상대적으로 건조한 대기 환경에서 생육하기 어려운 종임을 알 수 있었다. 따라서 재배지의 환경조건이 VPD 3.0kPa 이상의 건조한 환경이 자주 형성되는 곳은 어수리의 생육에 불리할 수 있으며, 눈개승마의 경우 어수리 보다 다소 건조한 대기환경에 더 높은 적응력을 지닌 것을 알 수 있었다.

• Nuclear Engineering and Technology
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• 제56권6호
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• pp.2174-2181
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• 2024

In this work, Sr_0.5Zr₂(PO₄)₃-SmPO₄ dual-phase ceramics were prepared via in-situ synthesis process, which is a potential novel nuclear waste form for immobilizing the fission product ⁹⁰Sr and the trivalent actinide radionuclides in high-level waste (HLW). And the preparation technology, microstructure and chemical durability of Sr_0.5Zr₂(PO₄)₃-SmPO₄ dual-phase ceramics were systematically investigated. It was confirmed that the optimum microwave-sintering temperature (1050 ℃) and heat preservation time (1.5 h) is estimated by Archimedes method. Besides, the as-prepared samples that were consisted of strontium zirconium phosphate (SrZP) and monazite showed the remarkable densification, in which the two crystalline phases were intermixed well with each other. Meanwhile, the formation and evolution of microstructure was also consistent with the variational rule of Sr_0.5Zr₂(PO₄)₃/SmPO₄, indicating that there was not mutual reaction during the in-situ synthesis process. The PCT and MCC-1 experimental results demonstrated that the elemental normalized leaching rates of tested samples are all at a low level (LR_Sr ~10^-4 g·m^-2·d^-1, LR_Zr ~10^-8-10^-6 g·m^-2·d^-1, LR_Sm ~10^-7-10^-5 g·m^-2·d^-1 and LR_P ~10^-4 g·m^-2·d^-1). It is indicated that Sr_0.5Zr₂(PO₄)₃-SmPO₄ dual-phase ceramics possesses excellent chemical durability for HLW disposal.