• Restorative Dentistry and Endodontics
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• 제42권4호
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• pp.316-323
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• 2017

Objectives: This study compared the amount of apically extruded bacteria during the glide-path preparation by using multi-file and single-file glide-path establishing nickel-titanium (NiTi) rotary systems. Materials and Methods: Sixty mandibular first molar teeth were used to prepare the test apparatus. They were decoronated, blocked into glass vials, sterilized in ethylene oxide gas, infected with a pure culture of Enterococcus faecalis, randomly assigned to 5 experimental groups, and then prepared using manual stainless-steel files (group KF) and glide-path establishing NiTi rotary files (group PF with PathFiles, group GF with G-Files, group PG with ProGlider, and group OG with One G). At the end of canal preparation, 0.01 mL NaCl solution was taken from the experimental vials. The suspension was plated on brain heart infusion agar and colonies of bacteria were counted, and the results were given as number of colony-forming units (CFU). Results: The manual instrumentation technique tested in group KF extruded the highest number of bacteria compared to the other 4 groups (p < 0.05). The 4 groups using rotary glide-path establishing instruments extruded similar amounts of bacteria. Conclusions: All glide-path establishment instrument systems tested caused a measurable apical extrusion of bacteria. The manual glide-path preparation showed the highest number of bacteria extruded compared to the other NiTi glide-path establishing instruments.

• 대한치과교정학회지
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• 제37권6호
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• pp.400-406
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• 2007

교정치료에서 고정원의 조절은 교정 장치의 선택과 적용에서 가장 중요한 요소 중 하나이다. 이 연구의 목적은 교정용 미니스크류의 식립 즉시 교정력을 적용한 군과 교정력을 적용하지 않은 군의 제거회전력 측정과 조직학적 분석을 통해 즉시 교정력을 가한 미니스크류의 고정원으로서의 안정성을 확인하여 식립 후 교정력을 적용 수 있는 시기의 선택에 도움을 주고자 하는 것이다. 외경 1.6 mm. 길이 8 mm인 총 40개의 타이타늄 미니스크류를 10마리 가토의 경골에 식립하였다. 20개의 미니스크류 실험군은 식립 직후부터 6주 동안 지속적인 200g의 교정력을 적용하였고 나머지 20개의 미니스크류 대조군은 교정력을 적용하지 않았다. 제거 회전력은 디지털 토크 게이지를 이용하여 측정하였으며 t-test를 이용하여 통계처리 하였고, 조직표본은 미니스크류를 제거한 후 H-E 염색하여 조직 소견을 관찰하였다. 제거회전력은 실험군과 대조군에서 통계학적으로 유의성 있는 차이를 보이지 않았으며, 조직학적으로 두 군간의 차이는 없었다. 본 연구의 결과는 교정용 미니스크류에 즉시 교정력을 가하더라도 안정적인 고정원으로 활용 할 수 있다는 점을 제시한다.

• Journal of Preventive Medicine and Public Health
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• 제32권3호
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• pp.269-275
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• 1999

Background : In April 6, 1990, a male researcher who has worked at a research unit at the Basic Research Building of Seoul National University(SNU) College of Medicine admitted to SNU Hospital due to persistent fever. He was diagnosed serologically as hemorrhagic fever with renal syndrome(HFRS). Another female researcher in the same unit was also diagnosed as HFRS at the same hospital several days later. Epidemic investigation of HFRS was conducted to determine the magnitude of the problems since these two cases were strongly suspected to have laboratory-acquired infections of HFRS. Methods : All researchers and employees working at the Basic Research Building(BRB) of SNU College of Medicine as of April 1, 1996 were recruited for the study, information on symptoms of HFRS and history of contact to experimental animals were collected by self-administered questionnaires and serological tests among study subjects were also conducted by indirect immunofluorescent antibody(IFA) to hantavirus. The experimental animals were also serologically tested for infection with hantavirus by IFA. Results : Among 218 surveyed, six researchers and an animal caretaker had hantavirus antibodies above 1:20 in IFA titer. Five of seven sero-positive subjects had antibodies above 1:640 in IFA titer and had shown clinical symptoms compatible to HFRS during Jan. 1 to Apr, 20, 1996. The sero-positive persons had handled animals more frequently than sero-negative persons (OR, 19,68; 95% Cl, 1.11-350.40) and handling animals at the animal quarter at School of Public Health(SPH) had shown consistently higher risk to get infected with hantavirus irrespective of types of animals handled (OR, 4.90-6.37). Sero-positivity of rats of the aniamal quarter at BRB was 30-60%, whereas 80% of rats at SPH tested were shown sero-positivity. Conclusion: There was a epidemic of HFRS in research units of a medical school during the period from Jan. through Apr, Further investigation is needed to determine the extent and the mode of transmission of the laboratory-acquired infection with hantavirus in other research facilities.

• 한국환경과학회지
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• 제22권1호
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• pp.17-23
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• 2013

In order to evaluate the effect of various organic soil conditioner ratios on the soil moisture content and growth of Cotoneaster horizontalis, a container type for wall-planting experiment was conducted in a greenhouse at Konkuk University under non-irrigation. The experimental planting grounds were prepared with different organic soil conditioner ratios ($A_1L_0$, $A_8L_1$, $A_4L_1$ $A_2L_1$ and $A_1L_1$), and a drought-tolerant ornamental variety of Cotoneaster horizontalis was planted. The change in soil moisture content, plant height, number of branches, number of dead leaves, number of leaves, number of shoots, length of node, length of leaf, width of leaf, root-collar caliper, chlorophyll content, and survival rate were investigated, from April to Jun 2010. The results of soil moisture content measurements were analyzed with weight units in the container type for wall-planting during the dry summer season. The soil moisture contents were significantly enhanced in the container type for wall-planting in increasing order as the amount of soil conditioner level was increased ($A_1L_1$ > $A_2L_1$ > $A_4L_1$ > $A_8L_1$ > $A_1L_0$). Compared to the control treatment application (amended soil with 100% + organic soil conditioner 0%), the highest plant growth was observed in the treatment of $A_1L_1$ application (amended soil with 50% + organic soil conditioner 50%). However, the differences between the organic soil conditioner ratio treatments of $A_1L_1$, $A_4L_1$, and $A_8L_1$ organic soil conditioner application were mostly not significant. The survival rate increased with the increasing application of organic soil conditioner, but in the control treatment application all the plants died. The experimental results from clearly demonstrated that the organic soil conditioner improved the survival rate more than the growth of Cotoneaster horizontalis. Therefore, Cotoneaster horizontalis is expected to be a highly valuable shrub for green wall systems, when considered for us in integration system or for increasing soil water contents in planting grounds.

• 환경영향평가
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• 제25권6호
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• pp.384-401
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• 2016

본 연구는 하천환경평가체계 구축의 일환으로서 식생 평가 지표 및 평가 기준의 검증을 목적으로 수행하였다. 본 연구를 위해 5개 시험하천을 대상으로 68개의 평가단위에서 총 204개의 식생 표본조사구를 설정하였으며, 표본조사구별 상관-종조성 수준에서 식생군집의 분류 및 현존식생도를 작성하였다. 현존식생도를 기준으로 식생자료의 분석을 통해 표본조사의 적정 규모, 식생 지수의 점수 기준, 식생 군집분류의 표준화, 그리고 식생평가지표의 등급화를 위한 종합 점수기준을 검토하였다. 하천 식생 평가를 위해 개발된 식생 다양도 지수와 식생 복잡도, 그리고 식생자연도 지수로 이루어진 식생평가지표의 종합점수 산정 및 등급화는 타당한 것으로 판단되었다. 식생평가지표의 등급화에 대한 식생지수의 기여도를 분석한 결과 식생자연도 지수가 다른 지수에 비해 보다 큰 역할을 하는 것으로 판단되었으나 세부 식생지수 사이의 상호보완적인 관계가 성립되어 있음을 확인할 수 있었다. 또한, 선행 연구에서의 기준의 재검토 및 식생군집 분류의 표준화 작업 등을 통해 개정된 기준을 적용한 결과 식생평가등급 간 변별력이 크게 확보되었음을 확인 할 수 있었으나, 하천구간의 유형에 따른 식생 지수 및 식생평가지표의 등급화는 큰 차이가 없는 것으로 나타났다.

• 한국가금학회지
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• 제33권1호
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• pp.41-47
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• 2006

본 연구는 산란계의 생산성과 계란의 품질에 미치는 지렁이 분말(EWM)의 첨가 효과를 구명하기 위해서 실시되었다. 총 360수의 55주령의 산란계를 공시하여서 EWM 0(대조구), 0.3, 0.6%를 첨가한 사료로 5주 동안의 사양 시험을 실시하였다. 계란은 매일 수집하여 난중을 측정하였고 산란율 및 사료 요구율은 시험기간 동안 매주 단위로 조사하였다. 뿐만 아니라 시험 마지막 주에는 계란의 품질도 측정하였다. 산란율과 일일 평균 산란량은 EWM 0.3 및 0.6% 급여 모두 대조구에 비해서 증가하는 경향이 인정되었지만, 0.3 % 와 0.6%처리구간에는 차이가 인정되지 않았다. 한편 사료 섭취량과 사료 요구율은 처리구간에 차이는 인정되지 않았다. 난각 두께, 강도, 색 및 난황색은 EWM 0.3 및 0.6% 처리구 모두 대조구와 비교해서 개선되는 경향이 인정되었다. 산란 1일째, haugh unit는 처리구간에 차이는 인정되지 않았지만, 보관기간에 따른 haugh unit의 변화는 EWM 급여구에서 커졌다. 지렁이분말(EWM)중의 As, Cd, Cr, Hg 및 Pb는 각각 4.41, 1.23, 1.18, 0.00 및 3.39ppm검출되었지만, 계란중에는 검출되지 않았다. 결론적으로 55주령의 산란계에 0.3%지렁이 분말(EWM)의 첨가는 산란계의 생산성 및 계란의 품질을 개선시킬 가능성이 인정된다.

• 한국작물학회:학술대회논문집
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• 한국작물학회 2017년도 9th Asian Crop Science Association conference
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• pp.338-338
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• 2017

One of the problems in increasing rice production is getting lines or varieties that have high adaptability so that able to produce maximum production in a variety of environmental conditions. One strategy that can be done to get adaptive varieties is through the improvement of native varieties. This research was conducted in rain fed paddy field, Aceh province, Indonesia from June to September 2014. The texture of the soil was clay-loam with the soil pH ranged from 6.5-6.7. Five potential progenies of rice from crossing between native Indonesian rice with introduced rice varieties consist of C3, C4, S3, S5, S6 were used in this study. Besides that, one national rice variety Ciherang also used as a comparison. The plants were growth in the plot with the size of $2m{\times}1.4m$ with plant distance was $20cm{\times}20cm$. The fertilizers used in this study were Urea, NPK, and KCl. Randomized block design with 6 rice progenies/variety and 3 replications were used in this study. There were 18 experimental units and each experimental unit had 10 samples for the sources of data. The variables that were observed in this study including plant height at harvesting time, number of productive tiller, the percentage of empty grains and filled grain per panicle, weight of filled grains per hill, weight of filled grain per plot and yield potential per hectare. Analyzed were also conducted for the depth of root penetration, dry-root weight, dry-shoot weight, shoot-root weight ratio and its correlation with the weight of filled grain per hill. The research results show that there was significant difference on plant height at harvesting time, number of productive tillers, the percentage of empty grains and filled grain per panicle, weight of filled grains per hill, weight of filled grain per plot and yield potential per ha (p>0.01) among the treatments. In addition, depth root penetration, dry-root weight, dry-shoot weight, shoot-root weight ratio also had significant difference (p>0.01) among the treatment. The highest plant at harvesting time was found in S6, reaching 129.8 cm and the shortest plants was found in C3 reaching 107.5 cm. The largest number of productive tillers and the highest percentage of filled grains per panicle were found in Ciherang reaching 10.5 tillers and 80.7% respectively. Ciherang also had the heaviest weight of filled grains per hill and per plot reaching 21.1 g and 2.18 kg respectively. Whereas, S6 had the lowest number of tillers and the lowest percentage of filled grain per panicle.. The highest yield potential per ha was found in Ciherang reaching 7.79 tons. Among the progenies, S5 had the highest yield potential reaching 5 tons/Ha. The result also showed significant relationship between shoot-root weight ratio with weight of filled grains per hill. The highest value of shoot-root weight ratio (1.57) in Ciherang is thought had closed relationship with its yield potential.

• Asian-Australasian Journal of Animal Sciences
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• 제19권6호
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• pp.811-815
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• 2006

The objective of this study was to evaluate the effect of electric fan installation for milk production improvement of dairy cattle in Thailand. The study was conducted using 2 small-holder dairy farms in Chiang Mai province, during April to August 2004. Electric fans were installed in front of each row of cows. Each of the two rows of cows in the barn was defined as an experimental unit, thus each farm had two experimental units. The fans were operated alternately in 7-day intervals between rows of cows within each farm during the day or between 8.00 am to 8.00 pm. Non-operation periods were used as control. Milk yields were recorded. Data on environmental temperature and humidity were obtained from Chiang Mai Meteorological Center. Result from statistically analysis of milk record suggested an interaction between lactation period and fan installation. Therefore, this interaction term of lactation period and fan installation (PERIOD_FAN) was added as a variable to the regression model. Due to the repeated data collection of milk yield from the same cow (alternate week), milk yield was analyzed by repeated measure analysis (Mixed model). Least square means were calculated for all levels and used to compare between each pair-wise values. The final data were collected from the total of 18 cows with 2,072 data. Overall means and SEM of milk yields and days in milk separated into farm were $14.7{\pm}0.06kg/day$ and $176.3{\pm}2.2days$, and $15.2{\pm}0.22kg/day$ and $202.5{\pm}3.7$ days for farm A and farm B, respectively. For multivariable analysis, only PERIOD_FAN and humidity were significantly associated with milk yield. Only the first period of lactation showed that the amount of milk yields during fan installation was higher than that of non-fan installation (p<0.05). Cows with fan installation produced approximately 1.2 kg/cow more milk than cows without fan installation during this period. In conclusion, the use of electric fan operated during the day time increased milk production of cows during the first period of lactation.

• 한국유기농업학회지
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• 제21권2호
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• pp.271-282
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• 2013

본 실험은 중부지방에서 벼 재배 시 유기 우분의 연용과 화학비료 시용이 유기 벼의 생산성, 볏짚의 사료가치 및 가축사육능력에 미치는 영향을 조사하였고, 결과를 요약하면 다음과 같다. 유기 벼의 생초수량, 건물수량, 식물 1개체 당 낱알의 건물 중 및 개수는 1, 2년차에는 화학비료 시용구가 유의하게 높았으나(p<0.05), 3년차에는 각 시험구 간 유의차는 없었다. 또한 수확지수는 3년 모두 화학비료 시용구가 유의하게 높았으며(p<0.05), 해가 거듭할수록 각 시험구 간의 차이가 약간 줄어드는 경향을 보였다. 또한 단위면적당 가축사육능력은 $K_{CP}$와 $K_{TDN}$의 평균값으로 비교해 보았을 때, 화학비료 시용구가 높은 값을 보였고, 각 시험구 간의 차이는 점점 줄어드는 경향을 보였다. 특히 $K_{ME}$의 경우 3년차에 우분 시용구가 유의한 차이는 없었지만 높은 값을 보이기도 하였다. 이상의 결과로 볼 때 중부 지방에서 유기 벼 재배 시 우분을 연용 했을 경우, 처음 1, 2년은 화학비료를 시용했을 때 보다는 수량이 낮았지만 3년차부터는 화학비료를 시용했을 때와의 격차가 줄어들기 시작하였으며, 추후 우분을 연용한다면 그 격차는 더욱 줄어들 것으로 판단된다.

• 한국해안·해양공학회논문집
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• 제28권5호
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• pp.277-283
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• 2016

테트라포드는 경사식 방파제의 피복재로 가장 많이 사용되는 콘크리트 소파블록이다. 테트라포드의 안정수를 계산하는 것은 테트라포드의 적정 중량을 결정하기 위해 필요한 과정이다. 1950년대의 Hudson 식부터 최근에 Suh and Kang이 제안한 식까지 테트라포드의 안정수를 계산하기 위한 다양한 경험식들이 제안되었다. 이러한 경험식들은 대부분이 식의 형태를 가정하고 실험 자료를 이용하여 식의 계수들을 회귀분석을 통해 결정하였다. 최근에는, 실험 데이터가 많은 경우, software engineering (또는 machine learning) 방법이 도입되고 있다. 예를 들어서, 방파제 피복석의 안정수를 계산하기 위한 인공신경망 모델이 제안된 바 있다. 그러나 이러한 방법들은 기존의 경험식보다 정확도가 크게 뛰어나지 않고 엔지니어들에게 생소하기 때문에 아직까지 설계에 거의 사용되지 않고 있다. 본 연구에서는 인공신경망 모델의 가중치와 편의를 이용하여 테트라포드의 안정수를 계산하는 양해법을 제안한다. 이 방법은 행렬 연산을 할 줄 아는 엔지니어라면 인공신경망에 대한 지식이 없어도 사용할 수 있으며, 기존의 경험식에 비해 정확도도 우수하다.