• 한국대기환경학회지
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• 제34권2호
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• pp.207-222
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• 2018

In this study, light absorption of carbonaceous species in $PM_{2.5}$ was investigated using a dual-spot 7-wavelength Aethalometer(model AE33) with 1-min time interval between January 01 and September 30, 2017 at an urban site of Gwangju. During the study period, two Asian dust (AD) events occurred in April (AD I) and May (AD II), respectively, during which light absorption in total suspended particles was observed. Black carbon (BC) was the dominant light absorbing aerosol component at all wavelengths over the study period. Light absorption coefficients by aerosol particles were found to have 2.7~3.3 times higher at 370 nm than at 880 nm. This would be attributed to light absorbing organic aerosols, which is called brown carbon (BrC), as well as BC as absorbing agents of aerosol particles. Monthly average absorption ${{\AA}}ngstr{\ddot{o}}m$ exponent ($AAE_{370-950nm}$) calculated over wavelength range of 370~950 nm ranged from 1.10 to 1.35, which was lower than the $AAE_{370-520nm}$ values ranging from 1.19~1.68 that was enhanced due to the presence of BrC. The estimated $AAE_{370-660nm}$ of BrC ranged from 2.2 to 7.5 with an average of 4.22, which was fairly consistent to the values reported by previous studies. The BrC absorption at 370 nm contributed 10.4~28.4% to the total aerosol absorption, with higher contribution in winter and spring and lower in summer. Average $PM_{10}$ and $PM_{2.5}$ concentrations were $108{\pm}36$ and $24{\pm}14{\mu}g/m^3$ during AD I, respectively, and $164{\pm}66$ and $43{\pm}26{\mu}g/m^3$ during AD II, respectively, implying the greater contribution of local pollution and/or regional pollution to $PM_{2.5}$ during the AD II. BC concentration and aerosol light absorption at 370 nm were relatively high in AD II, compared to those in AD I. Strong spectral dependence of aerosol light absorption was clearly found during the two AD events. $AAE_{370-660nm}$ of both light absorbing organic aerosols and dust particles during the AD I and II was $4.8{\pm}0.5$ and $6.2{\pm}0.7$, respectively. Higher AAE value during the AD II could be attributed to mixed enhanced urban pollution and dust aerosols. Absorption contribution by the light absorbing organic and dust aerosols estimated at 370 nm to the total light absorption was approximately 19% before and after the AD events, but it increased to 32.9~35.0% during the AD events. In conclusion, results from this study support enhancement of the aerosol light absorption due to Asian dust particles observed at the site.

• 한국조경학회지
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• 제37권1호
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• pp.50-64
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• 2009

도시 근교에 입지한 담수호소는 다양한 생물이 서식하는 생물다양성의 보고이나, 무계획적인 이용의 증가로 수질오염과 식생훼손의 위험에 직면해 있다. 이에 본 연구는 사천시 두량저수지를 대상으로 담수호소의 생물다양성 유지와 이용의 조화를 추구하기 위한 관리방안을 제안하고자 동 식물 생태계의 정밀한 조사 분석 자료에 근거한 관리지역 설정 과정을 거쳐 생물다양성 증진을 위한 생태적인 관리방안을 제안하였다. 생태계 조사 분석 자료를 바탕으로 비오톱 유형 평가, 야생동물 서식처 평가, 보호종 출현 유무를 종합한 결과, 생태계 보전지역으로 설정된 지역은 층위 구조가 형성된 자연림과 생물서식의 기반을 제공하는 수면 및 습지, 서식처 다양성이 높은 주연부 지역이 보전가치가 있었다. 관리지역은 식생이 교란된 지역, 오염강도가 높은 상업지, 공업지 등과 낚시로 인해 훼손된 수변지역으로, 식생천이 유도, 관목식재 등의 식생관리와 오염물질관리 체계 구축을 통한 적극적인 관리가 시도되어야 할 것이다. 담수호소에 있어 수변식생과 산림식생 훼손은 생물다양성 및 수질에 직접적인 영향을 미치므로 보존지역과 이용지역을 명확하게 구분하고 이용지역 이외에는 엄정하게 복원 관리하여야 할 것이다.

• 대한지리학회지
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• 제50권1호
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• pp.73-90
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• 2015

본 연구는 라오스 자본주의 발전의 지리제도적 분화와 다중스케일 분석에 주목한다. 또한 메콩유역권이 신제도주의 경제학과 경제지리학적 배열에 미친 영향을 논의하고 아시아 자본주의 다양성 접근법의 유용성을 제시한다. 본 연구는 상위 스케일에 연결되어 있는 다양한 국가 내 제도적 분포를 밝히기 위해 중국의 수요로 성장하고 있는 라오스의 고무산업을 사례로 선정하였다. 라오스 고무산업의 자본주의적 발전은 중국, 태국, 베트남 투자자들의 서로 다른 전략에 의한 지리제도적 분화를 보여준다. 이행기에 있는 라오스 자본주의의 분포를 정확하게 파악하는 것은 어렵지만, 고무산업에서 나타나는 증거는 다양한 제도적 분포가 존재함을 드러낸다. 그러나 포괄성의 부재는 지역발전 측면에서 우려되는 점이 있는데, 배타적 분포가 지역의 불균등한 발전과 불평등을 악화시킬 가능성이 높기 때문이다. 그리고 개발도상국 국가 내 자본주의의 다양성에 대한 이론을 정교화하기 위해 지역의 사적 자본주의 개념, 국가와 지역정부의 복합적 상호작용, 그리고 자본축적과 생계수단분석 간의 관계를 분명히 고려하는 것이 필요하다.

• Investigative Magnetic Resonance Imaging
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• 제19권3호
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• pp.178-185
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• 2015

Purpose: To compare the frequency of posterior globe flattening between two-dimensional T2-weighted imaging (2D T2WI) and three-dimensional (3D T2WI). Materials and Methods: Sixty-nine patients (31 female; mean age, 44.4 years) who had undergone both 5-mm axial T2WI and sagittal 3D 1-mm isovoxel T2WI of the whole brain for evaluation of various diseases (headache [n = 30], large hemorrhage [n = 19], large tumor or leptomeningeal tumor spread [n = 15], large infarct [n = 3], and bacterial meningitis [n = 2]) were used in this study. Two radiologists independently reviewed both sets of images at separate sessions. Axial T2WI and multi-planar imaging of 3D T2WI were visually assessed for the presence of globe flattening. The optic nerve sheath diameter (ONSD) was measured at a location 4 mm posterior to each globe on oblique coronal imaging reformatted from 3D T2WI. Results: There were significantly more globes showing posterior flattening on 3D T2WI (105/138 [76.1%]) than on 2D T2WI (27/138 [19.6%], P = 0.001). Inter-observer agreement was excellent for both 2D T2WI and 3D T2WI (Cohen's kappa = 0.928 and 0.962, respectively). Intra-class correlation coefficient for the ONSD was almost perfect (Cohen's kappa = 0.839). The globes with posterior flattening had significantly larger ONSD than those without on both 2D and 3D T2WI (P < 0.001; $6.14mm{\pm}0.44$ vs. $5.74mm{\pm}0.44$ on 2D T2WI; $5.90mm{\pm}0.47$ vs. $5.56mm{\pm}0.34$ on 3D T2WI). Optic nerve protrusion was significantly more frequent on reformatted 1-mm 3D T2WI than on 5-mm 2D T2WI (8 out of 138 globes on 3D T2WI versus one on 2D T2WI; P = 0.018). Conclusion: Posterior globe flattening is more frequently observed on 3D T2WI than on 2D T2WI in patients suspected of having increased intracranial pressure. The globes with posterior flattening have significantly larger ONSD than those without.

• Asian Pacific Journal of Cancer Prevention
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• 제14권11호
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• pp.6493-6499
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• 2013

Background: Non-epithelial malignant ovarian tumors and clear cell carcinomas, Brenner tumors, transitional cell tumors, and carcinoid tumors of the ovary are rare ovarian tumors (ROTs). In this study, our aim was to determine the clinicopathological features of ROT patients and prognostic factors associated with survival. Materials and Methods: A total of 167 patients with ROT who underwent initial surgery were retrospectively analyzed. Prognostic factors that may influence the survival of patients were evaluated by univariate and multivariate analyses. Results: Of 167 patients, 75 (44.9%) were diagnosed with germ-cell tumors (GCT) and 68 (40.7%) with sex cord-stromal tumors (SCST); the remaining 24 had other rare ovarian histologies. Significant differences were found between ROT groups with respect to age at diagnosis, tumor localization, initial surgery type, tumor size, tumor grade, and FIGO stage. Three-year progression-free survival (PFS) rates and median PFS intervals for patients with other ROT were worse than those of patients with GCT and SCST (41.8% vs 79.6% vs 77.1% and 30.2 vs 72 vs 150 months, respectively; p=0.01). Moreover, the 3-year overall survival (OS) rates and median OS times for patients with both GCT and SCST were better as compared to patients with other ROT, but these differences were not statistically significant (87.7% vs 88.8% vs 73.9% and 170 vs 122 vs 91 months, respectively; p=0.20). In the univariate analysis, tumor localization (p<0.001), FIGO stage (p<0.001), and tumor grade (p=0.04) were significant prognostic factors for PFS. For OS, the univariate analysis indicated that tumor localization (p=0.01), FIGO stage (p=0.001), and recurrence (p<0.001) were important prognostic indicators. Multivariate analysis showed that FIGO stage for PFS (p=0.001, HR: 0.11) and the presence of recurrence (p=0.02, HR: 0.54) for OS were independent prognostic factors. Conclusions: ROTs should be evaluated separately from epithelial ovarian cancers because of their different biological features and natural history. Due to the rarity of these tumors, determination of relevant prognostic factors as a group may help as a guide for more appropriate adjuvant or recurrent therapies for ROTs.

• Applied Microscopy
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• 제35권4호
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• pp.24-31
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• 2005

본 연구는 2002년 9월 묘지 이장 과정 중에 경기도 파주에서 발견된 여성미라 머리카락의 미세구조와 보존상태를 투과 및 주사전자현미경으로 관찰하였다. 16세기에 만들어진 미라의 머리카락은 완벽한 상태로 관찰되었다. 머리카락의 큐티클층과 피질 및 수질도 분해되거나 부서지지 않은 상태로 보존되어 있다. 큐티클층은 윤곽이 뚜렷하게 구별되는데 이 층은 $6{\sim}7$개의 큐티클세포들로 구성되어 있다. 각각의 큐티클세포는 세포사이막복합체에 의해서 견고하게 부착되어 있다. 피질은 거대원섬유들에 의해서 채워져 있으며 이들 사이에 멜라닌과립들이 산재되어 있다. 막대모양을 하고 있는 거대원섬유는 머리카락의 종축을 따라 평행하게 배열되어 있다. 특히, 피질에서 멜라닌과립은 큐티클층과 인접한 부위에 집중적으로 분포되어 있다. 440년 동안 머리카락이 보존된 원인은 머리카락을 피복하고 있는 다양한 물질들에 의해서 일어났는데, 피복물질을 에너지분산분광분석기로 분석한 결과 칼슘성분이 검출되었다. 머리카락 표면을 덮고 있는 칼슘이온은 머리카락에 수분이나 미생물 등의 접촉을 억제하는 역할을 하는 것으로 사료된다.

• 미생물학회지
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• 제46권4호
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• pp.326-333
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• 2010

2003년부터 2009년까지 서울지역 소아에서 분리된 nontyphoid Salmonella 105주에 대해서 혈청형, 항생제 내성양상, integron의 특징과 PFGE를 수행하였다. 혈청형은 총 18종으로 S.Enteritidis가 가장 많이 분리되었고, 그 다음은 Montevide였다. 항균제 내성은 혈청형별로 차이가 있었으나 전체 살모넬라에 대해서 10종의 항균제에 대한 내성률은 ampicillin이 60%로 가장 높았으며, tetracycline 46.7%, streptomycin 35.2%, nalidixic acid 28.6% 순이었다. 다재내성 유형을 알아본 결과 nalidixic acid 단독 내성이 15.7%로 가장 많았고, ampicillinampicillin/sulbactam-tetracycline형이 14.5%, ampicillin-streptomycin-chloramphenicol-tetracycline형이 10.8%였다. Integron에 대한 연구 결과 integron 보유율은 19%로 20주에서 class 1 integron을 가지고 있었고 gene cassette는 20%만 확인이 되었다. 확인된 gene cassette는 aadA2, blaP1과 dfrA12-aadA2, dfr17-aadA5, aadA7이였다. 연도별 분리균의 유연관계를 확인 하고자 가장 분리율이 높은 S. Enteritidis 50주에 대해서 PFGE를 수행한 결과 3가지 Pulsotype으로 나눠어졌다. 3주를 제외한 모든 균주는 similarity 89.8%의 비교적 유연관계가 높은 균임을 확인할 수 있었다.

• Restorative Dentistry and Endodontics
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• 제11권1호
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• pp.77-88
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• 1985

The purpose of this study was to examine the thermal diffusion through bases and restorations. The three principle types of base and two restorative materials were included in this study. They were representive brands of a zinc phosphate cement, a zinc oxide-eugenol cement, a calcium hydroxide paste, an amalgam and a composite resin (table 1). The specimens were prepared by placing the bases or restorative materials in laminated plastic molds. 5-mm diameter holes were prepared in the center of square of plastics which were 0.5, 1.0, 2.0, and 3.0mm thick respectively (fig. 1). All materials were manipulated in accordance with manufacturer's recommended proportions. All experimental procedures were carried out dividing them into eight different groups (table 2). Thermal diffusion was measured by means of digital thermometer (DP-100, RKC. instrument Inc. JAPAN) with the surface thermocouple placed on bottom surface of the specimen applying a constant source of heat and cold to the top surface of the each specimen. The thermal stimulus temperature applied on the each specimen surface was in the range of $60^{\circ}C$, $0^{\circ}C$ and $-50^{\circ}C$ respectively. The thermal change were recorded automatically on the multi-Pen recorder (R-16, Rikadenki, Co. JAPAN) connected with thermocouple tips which were centered on the bottom of the specimen. The following results were as follows, 1. Temperature diffusion was highest through amalgam and slowest through the composite resin. 2. As the thickness of restorations increased, the temperature change was decreased. 3. Thermal diffusion was slowest in the presence of zinc oxide-eugenol bases, followed by calcium hydroxide and zinc phosphate cement. 4. The efficiency of the cement bases in providing thermal insulation was dependent on their thickness beneath the restorations. 5. Thermal change was great in the range of $60^{\circ}C$ and $-50^{\circ}C$, but little in the range of $0^{\circ}C$.

• 한국치위생학회지
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• 제18권5호
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• pp.831-842
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• 2018

Objectives: This study was conducted to reveal the biological basis of dental plaque and preschool children's dental health status through repetitive and continuous toothbrushing instruction to preschool children, using quantitative criteria, and to emphasize the importance of the role of an oral health manager for the prevention of dental caries. Methods: After IRB approval, toothbrushing instruction and oral microbial specimen collection were conducted with children of preschool age at the Daycare Center attached to D. University, Busan. Specimens from 27 children were characterized by analysis with real-time multi-chain enzymatic polymerization reaction technique at an agency specializing in genetic analysis. Results: In a survey of the children's dental health behaviors, 48.1% responded that the toothbrushing time is 91 to 150 seconds; 66.7% responded that the frequency of toothbrushing is more than three times per day; 81.5% stated that they performed tongue brushing; and 81.5% brushed their teeth. Regarding levels of dental cariogenic bacteria, after children received continuous toothbrushing instruction, there were reductions in both Streptococcus mutans and Streptococcus sobrinus. Regarding toothbrushing time, the time increased in relation to the presence of instruction. Regarding Quigley Hein Index, the index decreased in the early and middle periods upon addition of instruction, then increased in the middle and later periods. Conclusions: Through persistent and repetitive toothbrushing instruction, healthy behavior can be positively established in children of preschool age; it is necessary to prepare institutional measures so opportunities for dental health education can be consistently provided and maintained. In the future, it will be necessary to conduct a follow-up study to verify the factors affecting toothbrushing time and volume of oral pathogens.

• Journal of Dairy Science and Biotechnology
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• 제28권2호
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• pp.13-18
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• 2010

방사선 조사된 완제품 조제분유를 포함한 시료 4종의 ESR 스펙트럼 특성을 측정하였다. 조제분유와 전지분유의 비조사 시료는 g=2.0050의 아주 약한 singlet 형태의 스펙트럼을 나타내었다. 조사 시료에서 전지분유는 g=2.0050의 singlet 형태의 스펙트럼, 조제분유는 전지분유와 같은 중심 피크 옆에 g=2.0006의 작은 피크를 가진 비대칭 형태의 스펙트럼을 나타내었고, 두 시료 모두 비조사 시료와 조사 시료의 신호 세기 차이가 명확하여 조사유무 판별이 가능하였다. 포도당과 유당의 비조사 시료는 아무런 시그널을 나타내지 않았으며, 조사 시료는 이미 알려져 있는 결정형 당 유래의 다형 피크를 가진 스펙트럼을 나타내었다. 선량이 증가함에 따라 신호 세기도 증가하였고, 회귀방정식의 상관계수는 0.95 이상의 높은 값을 나타내었다. 감마선과 전자선 조사에 의한 ESR 스팩트럼 간의 유의성 있는 차이는 없는 것으로 확인되었다. 결론적으로 본 실험을 통하여 ESR 분석은 방사선 조사된 조제분유 및 원료의 판별에 유용한 방법으로 적용될 수 있는 것으로 판단되었으며, 온도, 습도 및 전처리 조건 등의 요인에 의한 변화 가능성과 식품 생산 및 장기유통 기간 등을 고려할 때 이에 대한 지속적인 연구와 자료 축적이 요구된다고 할 것이다.