• The Plant Pathology Journal
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• 제32권2호
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• pp.85-94
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• 2016

Studies were conducted to determine the role of 3-methylthioproprionic acid (MTPA) in the pathogenicity of potato stem canker, Rhizoctonia solani, and the concentrations required to inhibit growth of R. solani under laboratory and plant house-based conditions. The experiments were laid out in a completely randomized design with five treatments and five replications. The treatments were 0, 1, 2, 4, and 8 mM concentrations of MTPA. The purified toxin exhibited maximal activity at pH 2.5 and $30^{\circ}C$. MTPA at 1, 2, 4, and 8 mM levels reduced plant height, chlorophyll content, haulm fresh weight, number of stolons, canopy development, and tuber weight of potato plants, as compared to the control. MTPA significantly affected mycelial growth with 8 mM causing the highest infection. The potato seedlings treated with MTPA concentrations of 1.0-8.0 mM induced necrosis of up to 80% of root system area. Cankers were resulted from the injection of potato seedling stems with 8.0 mM MTPA. The results showed the disappearance of cell membrane, rough mitochondrial and cell walls, change of the shape of chloroplasts, and swollen endoplasmic reticulum. Seventy-six (76) hours after toxin treatment, cell contents were completely broken, cytoplasm dissolved, and more chromatin were seen in the nucleus. The results suggested that high levels of the toxin concentration caused cell membrane and cytoplasm fracture. The integrity of cellular structure was destroyed by the phytotoxin. The concentrations of the phytotoxin were significantly correlated with pathogenicity and caused damage to the cell membrane of potato stem base tissue.

• Food Science and Biotechnology
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• 제14권1호
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• pp.73-76
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• 2005

The acaricidal activities of 12 commercial constituents derived from Eugenia caryophyllata leaf oils against Dermatophagoides farinae, D. pteronyssinus and Tyrophagus putrescentiae adults were examined using an impregnated fabric disk application and compared with that of the commercial benzyl benzoate as synthetic acaricide. On the basis of $LD_{50}$ values, the most toxic compound was methyl eugenol ($4.13\;{\mu}g/cm^2$), followed by methyl isoeugenol ($4.19\;{\mu}g/cm^2$), isoeugenol ($4.29\;{\mu}g/cm^2$), eugenol ($4.94\;{\mu}g/cm^2$), and acetyl eugenol ($13.91\;{\mu}g/cm^2$) against D. farinae. In the case of D. pteronyssinus, isoeugenol ($2.93\;{\mu}g/cm^2$) was the most toxic, followed by methyl isoeugenol ($3.28\;{\mu}g/cm^2$), methyl eugenol ($3.87\;{\mu}g/cm^2$), eugenol ($3.92\;{\mu}g/cm^2$), and acetyl eugenol ($7.21\;{\mu}g/cm^2$). These results suggest that D. pteronyssinus may be controlled more effectively by the application of eugenol congeners than D. farinae. In comparison with synthetic acaricides, the acaricidal activities of eugenol, isoeugenol, methyl eugenol, and methyl isoeugenol were about 1.9-2.2 times more toxic than benzyl benzoate. Furthermore, the most toxic constituent against T. putrescentiae was exhibited on eugenol ($10.11\;{\mu}g/cm^2$), followed by methyl eugenol ($38.67\;{\mu}g/cm^2$) and acetyl eugenol ($70.09\;{\mu}g/cm^2$), but no activity was observed for isoeugenol and methyl isoeugenol. The results suggested that eugenol congeners may be useful as a new source for selective control of house dust mites and stored food mites.

• 대한지역사회영양학회지
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• 제16권6호
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• pp.782-793
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• 2011

The purposes of this study were to classify university students by their lifestyle and to investigate the relationships between lifestyle and coffee satisfaction. The survey had been undertaken for 360 Korean and Chinese university students in Daejeon from November to December 2009. A total of 242 usable questionnaires were received with 67.2% response rate. The statistical analysis was performed by the SPSS 18.0 package program. Lifestyles of subjects, based on AIO (Activities, Interests, Opinions) method and factor analysis, were segmented into 2 groups of "outgoing activity" (n = 137) and "introverted devotion" (n = 105). "Outgoing activity" group exhibited highly health-oriented (p < 0.001) and convenience-oriented (p < 0.001) characteristics, but "introverted devotion" group showed highly goal-oriented (p < 0.01) and safety-oriented (p < 0.01) features. Comparing to "introverted devotion" group, "outgoing activity" group showed higher intake of coffee (p < 0.01) and more expense for beverage (p < 0.01). Three factors were extracted from 15 coffee quality attributes by factor analysis; "fundamentals", "supplement" and "inducement". These factors were positively correlated with coffee satisfaction according to lifestyle groups (p < 0.01). For "outgoing activity" group, 'fundamentals' was independent factor for satisfaction on coffee in coffee house (${\beta}$ = 0.268, p < 0.05) and canned or bottled coffee (${\beta}$ = 0.314, p < 0.01), and "supplement" was independent factor for satisfaction on coffee in vending machine (${\beta}$ = 0.235, p < 0.05). For "introverted devotion" group, "inducement" was independent factor for satisfaction on coffee in vending machine (${\beta}$ = 0.238, p < 0.001). These results provide an understanding for lifestyles of coffee consumers and give an insight into differentiated marketing plans for coffee industry.

• 한국화재소방학회논문지
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• 제19권4호
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• pp.69-74
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• 2005

본 연구는 건물화재의 정전시 완전 암흑상태에서 축광유도표지가 피난에 미치는 영향을 측정하기 위하여 조사하였다 실험조사는 대구 Fire EXPO '05에 실험 장치를 전시하여 엑스포 관람자 520명을 대상으로 2005년 5월 26일부터 29일까지 실시되었다. 실험 조사결과 안전 암흑상태일 때 피난자세는 남자의 경우 $70\%$, 여자는 $72\%$가 벽을 더듬으며 피난한 반면에 축광유도표지가 설치된 경우에는 남자의 경우 $88\%$, 여자의 경우 $83\%$가 선채로 피난을 한 것으로 나타났다. 나이별, 신장별, 시력별로 53초에서 64초까지 피난시간이 단축된 것으로 나타났다. 공공건물의 바닥에 축광유도표지를 설치하면 화재시 정전이 되더라도 평소와 다름없이 피난을 할 수 있는 것으로 나타났다.

• Wind and Structures
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• 제28권3호
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• pp.181-190
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• 2019

Light-frame wood structures have the ability to carry gravity loads. However, their performance during severe wind storms has indicated weakness with respect to resisting uplift wind loads exerted on the roofs of residential houses. A common failure mode observed during almost all main hurricane events initiates at the roof-to-wall connections (RTWCs). The toe-nail connections typically used at these locations are weak with regard to resisting uplift loading. This issue has been investigated at the Insurance Research Lab for Better Homes, where full-scale testing was conducted of a house under appropriate simulated uplift wind loads. This paper describes the detailed and sophisticated numerical simulation performed for this full-scale test, following which the numerical predictions were compared with the experimental results. In the numerical model, the nonlinear behavior is concentrated at the RTWCs, which is simulated with the use of a multi-linear plastic element. The analysis was conducted on four sets of uplift loads applied during the physical testing: 30 m/sincreased by 5 m/sincrements to 45 m/s. At this level of uplift loading, the connections exhibited inelastic behavior. A comparison with the experimental results revealed the ability of the sophisticated numerical model to predict the nonlinear response of the roof under wind uplift loads that vary both in time and space. A further component of the study was an evaluation of the load sharing among the trusses under realistic, uniform, and code pressures. Both the numerical model and the tributary area method were used for the load-sharing calculations.

• 한국동물위생학회지
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• 제46권2호
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• pp.167-173
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• 2023

An 8-year-old female neutered Maltese dog exhibited signs of serious thunderstorm phobia including panting, wandering, shivering, hiding, crying or whining, or trying to escape from the house. In this study, we administered clomipramine and alprazolam and observed behavioral improvement for 3 years. Clinical symptoms measured according to the storm phobia assessment (SPA) were significantly high with an initial total score of 19 points. However, it improved to a total score of 8 on day 176 after drugs administration and returned to the normal level with the total score of 5 points on the 983 days. When the symptoms for the first 4 treatments and the last 4 treatments were compared in 2 groups, the total score of all clinical symptoms decreased to -62.83% in the last 4 treatments. This study found that treatment with alprazolam and clomipramine was associated with a decrease in clinical signs of storm anxiety, suggesting that two drugs would be effective in reducing symptoms caused by anxiety, thunderstorm phobia, and noise phobia. In this follow up study, we hope that more studies would be conducted on behavior modification for treatment of storm phobia in veterinary medicine.

• Elastomers and Composites
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• 제59권2호
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• pp.73-81
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• 2024

In the field of electronic components, the potting material, which is a part of the electronic circuit package, plays a significant role in protecting circuits from the external environment and reducing signal interference among electronic devices during operation. This significantly affects the reliability of the components. Therefore, the accurate prediction and assessment of the lifespan of a material are of paramount importance in the electronics industry. We conducted an accelerated thermal aging evaluation using the Arrhenius technique on elastic potting material developed in-house, focusing on its insulation, waterproofing, and contraction properties. Through a comprehensive analysis of these properties and their interrelations, we confirmed the primary factors influencing molding material failure, as increased hardness is related to aggregation, adhesion, and post-hardening or thermal-aging-induced contraction. Furthermore, when plotting failure times against temperature, we observed that the hardness, adhesive strength, and water absorption rate were the predominant factors up to 120 ℃. Beyond this temperature, the tensile properties were the primary contributing factors. In contrast, the dielectric constant and loss tangent, which are vital for reducing signal interference in electric devices, exhibited positive changes(decreases) with aging and could be excluded as failure factors. Our findings establish valuable correlations between physical properties and techniques for the accurate prediction of failure time, with broad implications for future product lifespans. This study is particularly advantageous for advancing elastic potting materials to satisfy the stringent requirements of reliable environments.

• Journal of Veterinary Science
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• 제25권5호
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• pp.62.1-62.13
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• 2024

Importance: Antimicrobial resistance (AMR) is a serious public health threat. AMR bacteria and their resistance determinants in food can be transmitted to humans through the food chain and by direct contact and disseminate directly to the environment. Objective: This study examined the AMR characteristics and transferable R plasmids in Escherichia coli isolated from meat ducks raised in an open-house system. Methods: One hundred seventy-seven (n = 177) commensal E. coli were examined for their antimicrobial susceptibilities and horizontal resistance transfer. The plasmids were examined by PCR-based plasmid replicon typing (PBRT) and plasmid multi-locus sequence typing (pMLST). Results: The highest resistance rate was found against ampicillin (AMP, 83.0%) and tetracycline (TET, 81.9%), and most isolates exhibited multidrug resistance (MDR) (86.4%). The R plasmids were conjugally transferred when TET (n = 4), AMP (n = 3), and chloramphenicol (n = 3) were used as a selective pressure. The three isolates transferred resistance genes either in AMP or TET. The blaCTX-M1 gene resided on conjugative plasmids. Five replicon types were identified, of which Inc FrepB was most common in the donors (n = 13, 38.4%) and transconjugants (n = 16, 31.2%). Subtyping F plasmids revealed five distinct replicons combinations, including F47:A-:B- (n = 2), F29:A-:B23 (n = 1), F29:A-:B- (n = 1), F18:A-B:- (n = 1), and F4:A-:B- (n = 1). The chloramphenicol resistance was significantly correlated with the other AMR phenotypes (p < 0.05). Conclusions and Relevance: The meat ducks harbored MDR E. coli and played an important role in the environmental dissemination of AMR bacteria and its determinants. This confirms AMR as a health issue, highlighting the need for routine AMR monitoring and surveillance of meat ducks.

• 한국가금학회지
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• 제40권2호
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• pp.97-103
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• 2013

본 연구는 산란계의 동물복지를 적용한 운동장 면적에서 사육한 산란계의 생산성, 면역성 및 스트레스 반응에 미치는 영향을 조사하여 동물복지농가 육성과 안전축산물 생산을 위한 기초자료로 활용하고자 수행하였다. 사양시험은 13주령의 Hy-line-Brown 계열의 실용 산란계 90수를 공시하여 38주간 실시하였다. 대조구는 수당 $0.042m^2$ 면적의 케이지에서 사육(케이지 사육), 수당 축사 $0.11m^2$(평사)와 운동장 $1.1m^2$를 결합한 환경에서 사육($1.1m^2$ 운동장), 수당 축사 $0.11m^2$(평사)와 운동장 $2.2m^2$를 결합한 환경에서 사육($2.2m^2$ 운동장)으로 시험구를 편성하여 처리구당 3반복, 반복당 10수씩 난괴법으로 배치하여 시험하였다. 초기 산란율은 유의적으로 케이지 사육에서 유의적으로 높았으나(P<0.05), 중 후반기에는 운동장 사육 시험구에서 다소 높은 산란율을 보였다. 사료섭취량은 39주령까지 운동장 시험구에서 유의적으로 많았으나(P<0.05), 이후에서 종료 시 까지는 차이가 없었다. 시산일령은 대조구 비해 운동장 사육 시험구에서 16일 지연되었으며(P<0.05), 사육 환경이 계란의 품질에는 영향을 미치지 않았다. 면역 활성을 조사한 결과, 운동장사육 시험구에서 IgA는 유의적으로 높았고(P<0.05), IgG, IgM 및 corticosterone은 비교적 높았다. 결론적으로 산란계운동장 사육은 산란 초기의 생산성을 저하시키나, 중 후기의 생산성은 약간 증가를 보였으며, 면역성은 증가하였으나 스트레스는 다소간 더 받는 것으로 나타났다. 따라서 초기 산란율을 향상시키고, 적절한 외부의 환경에 의한 스트레스를 줄일 수 있는 사육 환경이 뒷받침된다면 운동장 사육이 동물복지형 사육으로 매우 적합한 사양방법이라고 사료된다.

• Journal of the Korean Association of Oral and Maxillofacial Surgeons
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• 제30권6호
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• pp.455-464
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• 2004

The purpose of this study was to evaluate and compare the influence of Steroid topical irrigation and implant surface on bone healing in the irradiated rabbit tibia. Implant to bone contact surface ratio and the pattern of bone healing around hydroxyapatite(HA) coated implant and pure titanium (Ti) implant which were inserted into the irradiated rabbit tibia were compared. 16 Korean house mature male rabbits were used as experimental animal. Each rabbit received 15 Gy of irradiation. 4 weeks after the irradiation, two holes were prepared in the irradiated tibia of each rabbits, where two surface type of implants were inserted :1) HA coated type and 2) pure Ti type. Right before placing implants, one group of rabbit received steroid irrigation and the other group did saline. After the irrigation, two implants of HA coated type and pure Ti type were inserted into the tibia of each rabbits. Each rabbit were sacrificed at 2nd, 4th, and 8th week after the implantation and the specimens were observed by the light microscope. The pattern of bone healing and histomorphometric analysis of the implant-bone interface were done. The results were as follows. 1. All implants inserted into the irradiated tibia of rabbit did not show any sign of clinical mobility and the bone around implants inserted into the irradiated tibia of rabbit did not show any resorption. 2. The bone to implant contact surface ratio around HA coated implants that received steroid irrigation got more bone to implant contact surface ratio than that of the saline irrigation. This result showed statistically significant(p<0.05). There was no statistically significant difference in 8th week group. 3. Though there was no statistically significant difference HA coated implants had more bone to implant contact surface ratio than pure Ti implant in 2nd and 4th groups, and there was no difference in 8th week group. 4. All implants inserted into the irradiated tibia of rabbit had exhibited successful osseointegraion.