• Maxillofacial Plastic and Reconstructive Surgery
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• 제34권6호
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• pp.384-390
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• 2012

Purpose: The purpose of this study is to examine in vivo osteogenesis of cultured human periosteal-derived cells and polydioxanone/pluronic F127 scaffold. Methods: Two one-year-old miniature pigs were used in this study. $2{\times}10^6$ periosteal-derived cells in 1 mL medium were seeded by dropping the cell suspension into the polydioxanone/pluronic F127 scaffold. These cell-scaffold constructs were cultured in osteogenic Dulbecco's modified Eagle's medium for 7 days. Under general anesthesia with azaperone and tiletamine-zolazepam, the mandibular body and ramus of the pigs were exposed. Three bony defects were created. Polydioxanone/pluronic F127 scaffold with periosteal-derived cells and the scaffold only were implanted into each defect. Another defect was left empty. Twelve weeks after implantation, the animals were sacrificed. Results: New bone formation was clearly observed in the polydioxanone/pluronic F127 scaffold with periosteal-derived cells. Newly generated bone was also observed in the scaffold without periosteal-derived osteoblasts and empty defect, but was mostly limited to the periphery. Conclusion: These results suggest that cultured human periosteal-derived cells have good osteogenic capacity in a polydioxanone/pluronic F127 scaffold, which provides a proper environment for the osteoblastic differentiation of these cells.

• 한국식품위생안전성학회지
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• 제38권6호
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• pp.508-516
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• 2023

본 연구는 팽이버섯 생산현장에서 사용하는 권지 접착포에서 팽이버섯으로 Listeria monocytogenes 교차오염을 예방하기 위하여 화학적 살균제에 의한 L. monocytogenes 저감 효과를 확인하였다. 과산화초산, 미산성전해수, 이산화염소수, 차아염소산나트륨을 10분간 처리했을 때 권지표면에 부착된 L. monocytogenes를 최대 99.99% 이상 저감화시켰고, 이들 4종의 살균소독제는 팽이버섯 유기물 존재 여부에 관계없이 높은 살균능을 보이므로 권지의 세척소독에 활용가능성이 있음을 확인하였다. 특히 과산화초산은 권지 접착포 거친면과 부드러운면 모두에서 L. monocytogenes를 99.999% 이상 감소시킬 수 있으므로 팽이버섯 권지 세척시 30mg/L 이상의 과산화초산에 30분 이상 침지한 후 사용하면 권지에 오염된 L. monocytogenes의 교차오염을 예방할 수 있을것으로 사료된다.

• Biomolecules & Therapeutics
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• 제24권3호
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• pp.260-267
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• 2016

Mesenchymal stem cells (MSCs) offer significant therapeutic promise for various regenerative therapies. However, MSC-based therapy for injury exhibits low efficacy due to the pathological environment in target tissues and the differences between in vitro and in vivo conditions. To address this issue, we developed adipose-derived MSC spheroids as a novel delivery method to preserve the stem cell microenvironment. MSC spheroids were generated by suspension culture for 3 days, and their sizes increased in a time-dependent manner. After re-attachment of MSC spheroids to the plastic dish, their adhesion capacity and morphology were not altered. MSC spheroids showed enhanced production of hypoxia-induced angiogenic cytokines such as vascular endothelial growth factor (VEGF), stromal cell derived factor (SDF), and hepatocyte growth factor (HGF). In addition, spheroid culture promoted the preservation of extracellular matrix (ECM) components, such as laminin and fibronectin, in a culture time- and spheroid size-dependent manner. Furthermore, phosphorylation of AKT, a cell survival signal, was significantly higher and the expression of pro-apoptotic molecules, poly (ADP ribose) polymerase-1 (PARP-1) and cleaved caspase-3, was markedly lower in the spheroids than in MSCs in monolayers. In the murine hindlimb ischemia model, transplanted MSC spheroids showed better proliferation than MSCs in monolayer. These findings suggest that MSC spheroids promote MSC bioactivities via secretion of angiogenic cytokines, preservation of ECM components, and regulation of apoptotic signals. Therefore, MSC spheroid-based cell therapy may serve as a simple and effective strategy for regenerative medicine.

• Geomechanics and Engineering
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• 제12권1호
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• pp.139-160
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• 2017

The bearing mechanism of tunnel-type anchorage (TTA) for suspension bridges is studied. Model tests are conducted using different shapes of plug bodies, which are circular column shape and circular truncated cone shape. The results show that the plug body of the latter shape possesses much larger bearing capacity, namely 4.48 times at elastic deformation stage and 4.54 times at failure stage compared to the former shape. Numerical simulation is then conducted to understand the mechanical and structural responses of plug body and surrounding rock mass. The mechanical parameters of the surrounding rock mass are firstly back-analyzed based on the monitoring data. The calculation laws of deformation and equivalent plastic strain show that the numerical simulation results are rational and provide subsequent mechanism analysis with an established basis. Afterwards, the bearing mechanism of TTA is studied. It is concluded that the plug body of circular truncated cone shape is able to take advantage of the material strength of the surrounding rock mass, which greatly enhances its bearing capacity. The ultimate bearing capacity of TTA, therefore, is concluded to be determined by the material strength of surrounding rock mass. Finally, recommendations for TTA design are proposed and discussed.

• The Plant Pathology Journal
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• 제30권1호
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• pp.25-32
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• 2014

Fusarium head blight (FHB; scab) caused mainly by Fusarium graminearum is a devastating disease of wheat and barley around the world. FHB causes yield reductions and contamination of grain with trichothecene mycotoxins such as deoxynivalenol (DON) which are a major health concern for humans and animals. The objective of this research was to develop an easy seed or seedling inoculation assay, and to compare these assays with whole plant resistance of twenty-nine Korean winter wheat cultivars to FHB. The clip-dipping assay consists of cutting off the coleoptiles apex, dipping the coleoptiles apex in conidial suspension, covering in plastic bag for 3 days, and measuring the lengths of lesions 7 days after inoculation. There were significant cultivar differences after inoculation with F. graminearum in seedling relative to the controls. Correlation coefficients between the lesion lengths of clip-dipping inoculation and FHB Type II resistance from adult plants were significant (r=0.45; P<0.05). Results from two other seedling inoculation methods, spraying and pin-point inoculation, were not correlated with adult FHB resistance. Single linear correlation was not significant between seed germination assays (soaking and soak-dry) and FHB resistance (Type I and Type II), respectively. These results showed that clip-dipping inoculation method using F. graminearum may offer a real possibility of simple, rapid, and reliable for the early screening of FHB resistance in wheat.

• The Plant Pathology Journal
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• 제23권3호
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• pp.223-225
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• 2007

Many plant growth-promoting rhizobacteria (PGPRs) have been known for beneficial effects on plants including biological control of soilborne pathogens, induced systemic resistance to plant pathogens, phytohormone production, and improvement of nutrient and water uptake of plants. We developed a simple and rapid method for screening potential PGPR, especially phytohormone producing rhizobacteria, or for analyzing their functions in plant growth using cucumber seedling cuttings. Surface-sterilized cucumber seeds were grown in a plastic pot containing steamed vermiculite. After 7 days of cultivation, the upper part 2 cm in length of cucumber seedling, was cut and used as cucumber cuttings. The base of cutting stem was then dipped in a microcentrifuge tube containing 1.5ml of a bacterial suspension and incubated at $25^{\circ}C$ with a fluorescent light for 10 days. Number and length of developed adventitious roots from cucumber cuttings were examined. The seedling cuttings showed various responses to the isolates tested. Some isolates resulted in withering at the day of examination or in reduced number of roots developed. Several isolates stimulated initial development of adventitious roots showing more adventitious root hair number than that of untreated cuttings, while some isolate had more adventitious root hair number and longer adventitious roots than that of untreated control. Similar results were obtained from the trial with rose cuttings. Our results suggest that this bioassay method may provide a useful way for differentiating PGPR's functions involved in the development of root system.

• 폴리머
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• 제38권2호
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• pp.225-231
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• 2014

고분자 결합제로 vinyl acetate(VA) 함량이 각각 30, 60%인 poly(ethylene-co-vinyl acetate)(EVA)를 사용하여 고농축 복합화약 시뮬란트의 유변학적 특성을 연구하였다. 충전제로는 탄산칼슘 및 research department explosive (RDX)와 물리적 특성이 유사한 Dechlorane을 사용하였다. 회분식 용융 혼련기를 사용하여 농축 현탁계를 혼련하였는데 최대 75 v%까지 충전이 가능하였다. 동적 기계적 물성 변화를 측정한 결과 Dechlorane이 탄산칼슘보다 결합제수지와 더 높은 상호작용을 보였다. 일정 전단속도 방식과 일정 전단응력 방식의 평판-평판 레오미터를 사용하여 현탁계의 미세구조의 변화가 유변물성에 미치는 영향을 조사하였고, Krieger-Dougherty 식을 사용하여 최대 충전 부피분율 및 고유점도를 구하였다. EVA31/Dechlorane 현탁계의 최대 충전 부피분율은 약 70 v%이고, 혼련시 전단응력이 약 2000 Pa 정도 부가되는 것이 적절함을 알 수 있었다.

• Korean Chemical Engineering Research
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• 제45권5호
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• pp.442-447
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• 2007

투명 플라스틱 필름의 표면강도를 향상시키기 위하여 유-무기 혼성 코팅용액을 Sol-Gel 법을 이용하여 합성하였다. 코팅용액은 입자 직경이 12 nm 크기의 무기물인 colloidal silica 용액(Ludox)에 유기물인 GPTMS(glycidoxypropyl trimethoxysilane)를 첨가하여 제조하였다. 그 후에 기재인 PC(polycarbonate) 필름에 담금 코팅(dip-coating)시키고, 상온에서 10분 동안 건조시킨 후, $80^{\circ}C$에서 30분 동안 열 경화시켜 하드 코팅 막을 제조하였다. 이 과정 중 코팅용액의 pH 변화와 GPTMS 첨가량의 변화가 코팅 막의 물성에 미치는 영향을 살펴보았다. pH 4의 산성 조건에서 제조된 코팅용액으로 PC 필름 위에 코팅한 경우는 중성이나 염기성 조건으로 제조된 경우 보다 우수한 연필경도 및 기재와의 부착력을 보였다. 또한 GPTMS의 첨가량이 증가할수록 코팅 막의 연필경도 및 기재와의 부착력이 증가하였다.

• 대한수의학회지
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• 제40권2호
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• pp.311-323
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• 2000

Immunosuppressive effects of reticuloendotheliosis virus (REV) infection in chickens were investigated. Primary antibody responses to Newcastle disease virus (strain B1) and sheep red blood cells were significantly low in chickens inoculated with the local isolate 89-74 of REV compared to those of uninfected chickens. In chickens infected with REV strain T or 89-74, blastogenesis of spleen cells and peripheral blood lymphocytes (PBL) to concanavalin A (Con A) was severely suppressed. When specific pathogen free (SPF) chickens were inoculated with the isolate, the suppressive effect was observed up to 7 weeks of age while, in the contact infected chickens, the suppression was absent. Similar suppressive effects were observed in chickens inoculated with REV strain T at 2, 3 and 4 weeks of age. When spleen cells or PBL from uninfected chickens were co-cultured with spleen cells or PBL from chickens infected with REV at 1 day-old or 2 week-old, the blastogenesis of the normal cells was suppressed. The suppressive effect of PBL from REV-infected chickens on normal lymphocytes was abrogated by the treatment with trypsin. However the suppressive activity of the REV-infected PBL was not influenced at removing machrophage from the cell suspension by incubation in plastic petri dishes. In addition to the immunosuppression, chickens infected with the REV isolate showed abnormal feather development (nakanuke), anemia, paralysis and retarded growth. Three out of 11 chickens inoculated with the isolate at day-old died between 6 and 9 weeks of age by bacterial infections.

• 원예과학기술지
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• 제30권4호
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• pp.426-431
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• 2012

Fusarium oxysporum f. sp. lycopersici(FOL)에 의해 발생하는 토마토 시들음병에 대한 효과적인 저항성 검정법을 확립하기 위하여, 시판 중인 토마토 6개 품종에서 FOL 5개 균주에 의한 시들음병 발생을 조사한 후에 토마토 2개 품종(도태랑마스터, race 1 저항성; 슈퍼선로드, race 1과 2 저항성)과 FOL 2개 균주(KACC40043, race 2; TF104, race 3)를 선발하였다. 선발한 토마토 품종과 FOL 균주를 이용하여 뿌리 상처 유무, 재배 온도, 접종원 농도 및 포자현탁액에 침지하는 시간 등에 따른 시들음병 발생을 조사하였다. FOL에 대한 토마토 품종의 저항성 및 감수성 반응은 레이스 특이적이며, $20^{\circ}C$의 재배온도를 제외한 실험한 모든 발병 조건에 의해 이들 반응은 영향을 받지 않았다. 그리고 FOL에 의한 토마토 시들음병 발생의 최적 온도는 $25-30^{\circ}C$임을 알 수 있었다. 따라서, 토마토 시들음병에 대한 저항성을 효과적으로 검정하는 방법으로 2엽기 토마토 유묘의 뿌리를 $1{\times}10^7conidia/mL$ 농도의 FOL 포자 현탁액에 30분간 침지한 후에 원예용 상토에 이식하고 $25^{\circ}C$ 생육상에서 하루에 12시간씩 광을 조사하면서 3주 동안 재배하는 것을 제안한다.