• Bulletin of the Korean Chemical Society
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• 제23권2호
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• pp.225-228
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• 2002

Amorphous $Ga_2O_3$ films have been grown on Si(100) substrates by metal organic chemical vapor deposition (MOCVD) using gallium isopropoxide, $Ga(O^iPr)_3$, as single precursor. Deposition was carried out in the substrate temperature range 400-800 $^{\circ}C$. X-ray photoelectron spectroscopy (XPS) analysis revealed deposition of stoichiometric $Ga_2O_3$ thin films at 500-600 $^{\circ}C$. XPS depth profiling by $Ar^+$ ion sputtering indicated that carbon contamination exists mostly in the surface region with less than 3.5% content in the film. Microscopic images of the films by scanning electron microscopy (SEM) and atomic force microscopy (AFM) showed formation of grains of approximately 20-40 nm in size on the film surfaces. The root-mean-square surface roughness from an AFM image was ${\sim}10{\AA}$. The interfacial layer of the $Ga_2O_3$/Si was measured to be ${\sim}35{\AA}$ thick by cross-sectional transmission electron microscopy (TEM). From the analysis of gaseous products of the CVD reaction by gas chromatography-mass spectrometry (GC-MS), an effort was made to explain the CVD mechanism.

• Journal of Crop Science and Biotechnology
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• 제11권2호
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• pp.91-100
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• 2008

Melting curve analysis of fluorescently labeled DNA fragments is used extensively for genotyping single nucleotide polymorphism(SNP). Here, we evaluated a SNP genotyping method by melting curve analysis with the two probe chemistries in a 384-well plate format on a Roche LightCycler 480. The HybProbe chemistry is based on the fluorescence resonance energy transfer(FRET) and the SimpleProbe chemistry uses a terminal self-quenching fluorophore. We evaluated FRET HybProbes and SimpleProbes for two SNP sites closely linked to two quantitative trait loci(QTL) for southern root-knot nematode resistance. These probes were used to genotype the two parents and 94 $F_2$ plants from the cross of PI 96354$\times$Bossier. The SNP genotypes of all samples determined by the LightCycler software agreed with previously determined SSR genotypes and the SNP genotypes determined on a Luminex 100 flow cytometry instrument. Multiplexed HybProbes for the two SNPs showed a 98.4% success rate and 100% concordance between repeats two of the same 96 DNA samples. Also, we developed a HybProbe assay for the Rcs3 gene conditioning broad resistance to the frogeye leaf spot(FLS) disease. The LightCycler 480 provides rapid PCR on 384-well plate and allows simultaneous amplification and analysis in approximately 2 hours without any additional steps after amplification. This allowed for a reduction of the potential contamination of PCR products, simplicity, and enablement of a streamlined workflow. The melting curve analysis on the LightCycler 480 provided high-throughput and rapid SNP genotyping and appears highly effective for marker-assisted selection in soybean.

• 한국식품조리과학회지
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• 제30권1호
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• pp.51-63
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• 2014

A microbiological quality evaluation on cooked food, food materials and cooking equipment was conducted in 14 school food services in Changwon area, South Korea for Ojingeochaesomoochim (vegetable salad with blanched squid) which went through cooking process after heating treatment. Only 5 schools out of the 14 (35.7%) observed the sanitization criteria of the Korean School Meals Sanitization Management for raw vegetables (concentration of chlorine solution: 100ppm, immersion time of sanitizing: 5 min). The acceptance rates regarding the microbial standards for Korean school meals showed improvement before and after of sanitization: for onions 57.1% vs 71.4%; cucumber 42.9% vs. 78.6%. However, garlic showed adverse sanitizing effect as the acceptance rate went down from 42.9% to 35.7%. Blanched squid and red pepper paste was acceptable in all 14 schools (100%), while squid seasoned with red pepper powder was acceptable in only 42.9% of the schools. Microbial results for knives, cutting boards, mixing bowls were satisfactory, however 35.7% of sanitary gloves that were put on right before the seasoning showed poor sanitization, and this indicated high probability of cross-contamination from the gloves. We calculated that 57.1% of the cooked foods were in accordance with the microbial standards for Korean school meals. Therefore, it is strongly recommended to have verification process, especially on the effectiveness of sanitization of raw vegetables, in cooking foods through cooking process after heating treatment in HACCP system of school food service.

• 한국산업정보학회:학술대회논문집
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• 한국산업정보학회 2000년도 춘계학술대회논문집
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• pp.59-64
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• 2000

능동 레이더 반사기는 지금까지는 특히 비행물체와 미사일의 레이더 유효 반사 면적을 효과적으로 증가시키기 위한 군사적 응용에만 사용이 제한되어져 왔기 때문에 그다지 친숙한 용어는 아니다. 레이더 트랜스폰더의 가장 잘 알려진 응용은 군용의 피아 식별 장치 (IFF ; Identification Friend or Foe)와 이것의 민간 항공부문이고, 항공 교통 관제(An , hir Traffic Control)를 위한 2차 감시 레이더(SSR : Second Surveillance Radar), 그리고 보다 최근에는 전 세계 해상 조난 및 안전 제도(GMDSS ; Global Maritime Distress and Safety System)의 수색 구조용 트랜스폰더(SART ; Search And Rescue Transponder)등이 있다. 최근 연안이나 대양에서의 해난사고가 빈번히 발생되고 있으므로, 이로 인한 해양오염이 심각한 실정이다. 이제는 전통적인 항해표지 및 시설로써 해상교통의 안전을 유지하기에는 충분치 못하며, 새로운 개념과 구조가 적용되어야만 한다. 따라서 본 연구에서는 개선된 구조를 가진 능동 레이더 반사기를 제안하고 제작하였다. 제작된 시스템은 기존의 시설에 비해 높은 성능 향상을 보인다.

• Journal of Trauma and Injury
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• 제33권1호
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• pp.18-22
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• 2020

Purpose: Damage control laparotomy has contributed to improved survival rates for severe abdominal injuries. A large part of severe abdominal injury occurs with a concomitant pelvic bone fracture. The safety and effectiveness of internal fixation of pelvic bone fracture(s) has not been established. The aim of the present study was to evaluate infection risk in the pelvic surgical site in patients who underwent emergent abdominal surgery. Methods: This single-center retrospective observational study was based on data collected from a prospectively maintained registry between January 2015 and June 2019. Patients who underwent laparotomy and pelvic internal fixation were included. Individuals <18 and ≥80 years of age, those with no microbiological investigations, and those who underwent one-stage abdominal surgery were excluded. Comprehensive statistical comparative analysis was not performed due to the small number of enrolled patients. Results: A total of six patients met the inclusion criteria, and the most common injury mechanism was anterior-posterior compression (67%). The average duration of open abdomen was 98 hours (range, 44-98), and the time interval between abdominal closure and pelvic surgery was 98 hours. One patient (16.7%) died due to multi-organ dysfunction syndrome. Micro-organisms were identified in the abdominal surgical site in five patients (83%), with no micro-organisms in pelvic surgical sites. There was no unplanned implant removal. Conclusions: Internal fixation of pelvic bone fracture(s) could be performed in the state of open abdomen, and the advantages of early fixation may countervail the risks for cross contamination.

• 미생물학회지
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• 제43권1호
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• pp.1-6
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• 2007

Epstein-Barr virus (EBV), cytomegalovirus (CMV), hepatitis B virus (HBV), parvovirus B19 (B19)등 4종의 바이러스는 인체에 감염을 일으키는 병원체로서 DNA를 유전물질로 함유한다. 각 바이러스 유전자의 염기서열을 분석하여 EBV CMV, HBV의 pol 유전자와 B19의 ns 유전자에 특이적으로 결합할 수 있는 primer를 설계 제작하고 단일 시험으로 4종의 바이러스를 동시에 검출할 수 있는 다중 중합효소 연쇄반응(Multiplex PCR)법을 확립하였다. Primer 염기서열, PCR 반응조성물의 농도, PCR 반응시간 및 온도조건을 최적화하여 민감도를 증대시킴으로써, 단일 시험으로 5-10 분자수의 유전물질까지 검출이 가능하였다. 또한 4종의 바이러스 사이에 교차반응이 일어나지 않았으며 생체시료를 이용한 시험에서도 특이성과 민감도가 유지됨을 확인하였다. 그러므로 본 연구에서 확립한 다중 중합효소 연쇄반응은 세포배양액 또는 생체 시료에 감염된 4종 DNA 바이러스진단에 효율적으로 이용할 수 있을 것이라고 판단된다.

• Environmental Analysis Health and Toxicology
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• 제28권
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• pp.9.1-9.5
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• 2013

Objectives Geographic Information Systems (GIS) is a powerful tool for assessing exposure in epidemiologic studies. We used GIS to determine the geographic extent of contamination by perfluorooctanoic acid, C8 (PFOA) that was released into the environment from the DuPont Washington Works Facility located in Parkersburg, West Virginia. Methods Paper maps of pipe distribution networks were provided by six local public water districts participating in the community cross-sectional survey, the C8 Health Project. Residential histories were also collected in the survey and geocoded. We integrated the pipe networks and geocoded addresses to determine which addresses were serviced by one of the participating water districts. The GIS-based water district assignment was then compared to the participants' self-reported source of public drinking water. Results There were a total of 151,871 addresses provided by the 48,800 participants of the C8 Health Project that consented to geocoding. We were able to successfully geocode 139,067 (91.6%) addresses, and of these, 118,209 (85.0%) self-reported water sources were confirmed using the GIS-based method of water district assignment. Furthermore, the GIS-based method corrected 20,858 (15.0%) self-reported public drinking water sources. Over half (54%) the participants in the lowest GIS-based exposure group self-reported being in a higher exposed water district. Conclusions Not only were we able to correct erroneous self-reported water sources, we were also able to assign water districts to participants with unknown sources. Without the GIS-based method, the reliance on only self-reported data would have resulted in exposure misclassification.

• Journal of Periodontal and Implant Science
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• 제39권sup2호
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• pp.239-251
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• 2009

Purpose: Full-mouth disinfection enables to reduce the probability of cross contamination from untreated pockets to treated ones, for completing the entire SRP under local anesthesia with chlorhexidine as a mouth wash in two visits within 24 hours. This study aimed to compare the clinical effects of modified full-mouth disinfection (Fdis) after 6 months with those of conventional SRP (cSRP). Methods: Thirty non-smoking chronic periodontitis subjects were randomly allocated two groups. The Fdis group underwent the entire SRP under local anesthesia in two visits within 24 hours, a week after receiving supragingival scaling. A chlorhexidine (0.1%) solution was used for rinsing and subgingival irrigation for Fdis. The cSRP group received SRP per quadrant under local anesthesia at one-week intervals, one week after they had received scaling. Clinical parameters were recorded at baseline, after 1, 3 and 6 months. Results: There are significant (P<0.05) decreases in the sulcus bleeding index, and plaque index, and the increases in gingival recession were significantly smaller with Fdis after six months compared with cSRP. There was significant improvement in the probing depth and clinical attachment level for initially medium-deep pockets (4-6mm) after Fdis compared with cSRP. Multi-rooted teeth showed significantly larger attachment gain up to six months after Fdis. Single-rooted teeth showed significantly more attachment gain, 1 and 6 months after Fdis. Conclusions: Fdis has more beneficial effects on reducing gingival inflammation, plaque level, probing depth, gingival recession and improving clinical attachment level over cSRP.

• 한국환경보건학회지
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• 제40권4호
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• pp.304-312
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• 2014

Objectives: This study was performed to examine bioaerosols in indoor air in public restrooms, as well as to assess the effects of air temperature and relative humidity on bioaerosol levels. Methods: A cross-sectional survey was performed in ten male and ten female restrooms. An air sampler (Anderson type) was used for sampling total suspended bacteria (TSB), Gram-negative bacteria (GNB), Gram-positive bacteria (GPB), opportunistic bacteria (OP), Staphylococcus spp., and total suspended fungi (TSF). Results: The levels of TSB were $10-10^2CFU/m^3$ and TSF $10-10^2CFU/m^3$, respectively. The GNB level was $0-10CFU/m^3$, and GPB and OP levels were $10-10^2CFU/m^3$. Staphylococcus aureus and methicillin-resistant S. aureus (MRSA) were detected in 90% of the restrooms. The GPB level was higher in the female restrooms than in the male restrooms (p < 0.05). TSB, GNB, and TSF showed higher levels in restrooms in buildings over 30 years old (p < 0.01). The main effect of air temperature or relative humidity and interaction effect of the two factors on the TSB level were significant (p < 0.05), while the effect of relative humidity on the TSF level was significant (p < 0.001). Conclusions: These results indicate that there is a wide variation in the bioaerosol levels among different restrooms. The observed differences in bioaerosol levels reflect different building histories. The effects of air temperature and/or relative humidity reveal that bioaerosol levels may vary according to season or time of day. Future research is needed to further characterize the relation between the bioaerosol levels and surface contamination in restrooms.

• 한국치위생학회지
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• 제12권3호
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• pp.641-646
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• 2012

Objectives : The purpose of this study is to analyze the sterilizing effects of toothbrushes by administering bacteria into toothbrushes and reproducing the antibacterial effects using a microwave oven. Methods : The heads of four-row mid-strength toothbrushes were cut, put in a bacterial solution ($3{\times}10^9cells/ml$) for vortexing, and sterilized with microwaves for 0, 30, and 60 seconds. They were then moved into four tubes containing DW 10 ml and suspended in a vortex mixer for two minutes to separate bacteria from them. DW 9ml was added by 1ml of bacteria for dilution of $10{\sim}10^6$ times. It was then administered to the BHI agar plate by 0.1ml and cultured at $37^{\circ}C$ for 24 hours. Total number of bacteria adhered to a toothbrush was obtained by multiplying the number of colonies by the dilution factor. The experiment was done in the first, second, and third step, being repeated in a normal temperature drier ($23^{\circ}C$) after 5, 9 and 24 hours. Results : The results of the experiment revealed that the sterilizing effects were 95% or over. When toothbrushes were sterilized for 60 seconds, the number of colonies is about 11 after drying for 5 hours, 7 after drying for 9 hours and 2 after drying for 24 hours. The sterilizing effects reached 98% when the bacteria-administered toothbrush was sterilized for 1 minute after drying for 24 hours. Conclusions : The results demonstrated that toothbrush sterilizing by using microwave is a suitable way to prevent cross-contamination of toothbrushes by oral bacterial infection and thus easy to use at home. However, this study suggests that toothbrush sterilizing by using microwave should be limited within two times a week because the physical properties of toothbrush might be changed.