• 한국응용과학기술학회지
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• 제26권1호
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• pp.45-50
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• 2009

Three-dimensional, statistical-mechanical formulations of problems are usually untractable analytically, and therefore they are commonly solved numerically. However, their one-dimensional counterparts are always to be solved analytically. In general analytical solutions sheds more insights to the problems than numerical solutions. Hence, solutions of one-dimensional problems may provide key properties to the problems, when they are extended to three dimensions. In this article, thermodynamic properties of one-dimensional fluid comprising molecules of rigid rods are analyzed statistical-mechanically. Molecules of rigid rods are characterized with repulsive or excluded volume effect. It is observed that this feature is well reflected in thermodynamic functions such as Helmholtz free energy. volumetric equation of state. chemical potential, entropy, etc.

• 한국전기전자재료학회:학술대회논문집
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• 한국전기전자재료학회 1997년도 춘계학술대회 논문집
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• pp.127-129
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• 1997

The high pretilt angles in nematic liquid crystals (NLCs) have been generated on robbed polythiophene (PTP) surfaces with alkyl chain lengths. The pretilt angle of the NLC was observed on unidirectionally rubbed PTP surfaces with alkyl chains with more than 9 carbon atoms. We obtained the Pretilt angle of 15~40$^{\circ}$ on rubbed PTP surfaces with 10 carbon atoms in the a1ky1 chain. Also, the pretilt angles of 65~80$^{\circ}$ of NLC were obtained on rubbed PTP surfaces with 11 and 12 carbon atoms in the alkyl chain. We suggest that this high pretilt angle generation in NLC is due to the surface-excluded volume effect by the alkyl chain lengths between. the LCs and the PTP surfaces. Finally, we conclude the odd-even effect on rubbed PTP surfaces is clearly contributed to the pretilt angle generation.

• 한국간담췌외과학회지
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• 제27권4호
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• pp.394-402
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• 2023

Backgrounds/Aims: Acute pancreatitis is an emergency presentation, which can range from mild to life threatening. Intravenous fluids are the cornerstone of management. Although the WATERFALL trial described the optimal fluid rate in mild/moderate pancreatitis, this trial excluded patients with moderate-severe/severe pancreatitis. The aim of this study was to establish clinical practice regarding intravenous fluid administration in acute pancreatitis and assess its effect on mortality. Methods: Prospective multi-centre audit of patients with acute pancreatitis was conducted. Data were collected regarding intravenous fluid administration within 72 hours of admission. The primary outcome was 30-day mortality. Multivariable logistic regression was used to identify predictors of 30-day mortality. Results: Those with severe pancreatitis received more fluid; median 5.7 L versus 4 L in 72 hours (p = 0.003). Participants with severe pancreatitis who died within 30 days received a median of 2,750 mL in the first 24 hours, compared to 4,000 mL in those who survived. The following factors were significant predictors of 30-day mortality: age, Glasgow score, C-reactive protein, ischaemic heart disease, and pancreatitis aetiology. Overall, volume of intravenous fluid was not associated with mortality. However, the effect of intravenous fluid volume on mortality differed significantly depending on pancreatitis severity. In severe pancreatitis, increased volume of intravenous fluid was associated with significant reductions in mortality (odds ratio = 0.655; 0.459-0.936; p = 0.020). Conclusions: In severe pancreatitis, more aggressive fluid prescription was associated with decreased mortality; however, this was not the case in milder disease. Further prospective trials guiding fluid resuscitation in severe pancreatitis are needed, as the impact of fluid on this population appears to differ from that in those with milder disease.

• Bulletin of the Korean Chemical Society
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• 제22권11호
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• pp.1255-1260
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• 2001

The expansion of two different kinds of hydrodynamic size of polymethyl methacrylate (PMMA Mw: 1.56- 2.04 ${\times}$ 106 g/mol) has been measured by dynamic light scattering and viscometry above the Flory $\theta$ temperature of the variou s solvents such as n-butyl chloride, 3-heptanone, and 4-heptanone. The expansion of PMMA chains was analyzed in terms of universal temperature parameters and also compared with previous results of polystyrene (PS) system. First it was found that simple $\tau/{\tau}c$ parameter no longer had its universality for the expansion behavior of hydrodynamic size in the chemically different linear polymer chains. However after modifying ${\tau}/{\tau}c$ parameter into $(Mw/Ro2)3}2(\tau/\tauc)$, we observed a much better universality for both PMMA and PS systems. Here Mw, Ro, $\tau[=(T-{\theta}$)/${\theta}$]$, and ${\tau}c[=({\theta}-Tc)/Tc]$ are defined as the weight average molecular weight, the unperturbed end-to-end distance, the reduced temperature and the reduced critical temperature, respectively.

• 자원ㆍ환경경제연구
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• 제13권2호
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• pp.195-218
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• 2004

본 논문은 환경오염저감비용이 무역수지에 미치는 영향에 대해 살펴보았다. 산업연관표를 이용하여 각 산업별 오염저감비용 지출이 생산자물가에 미치는 영향을 분석하고 다시 이를 이용하여 산업별 수출입에의 영향을 도출하였다. 본 연구의 중요한 기여는 이전의 연구에서 제외되었던 오염저감비용 지출의 간접효과를 명시적으로 고려해 줌으로써 분석의 정확도를 높였다는 점이다. 산업연관표를 이용한 분석에서 오염저감비용 지출이 미친 무역수지에의 영향은 총 교역량의 0.30~0.46%로 미국의 1970년대 수준보다 낮았다.

• 대한방사선기술학회지:방사선기술과학
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• 제33권3호
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• pp.239-243
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• 2010

전립선암을 조기진단하기 위한 선별검사로 혈청 전립선특이항원(serum prostate-specific antigen)과 경직장초음파검사(transrectal ultrasonography)가 널리 쓰이고 있으나 어느 한 가지 방법만으로는 진단적 정확성을 갖지 못하여 상호보완적으로 진단이 이루어지고 있다. 이 연구에서는 혈청 전립선특이항원과 경직장초음파검사에 의해 측정된 전립선용적과의 상관관계를 알아보고자 하였다. 연구의 대상은 2008년 01월부터 2008년 12월까지 D대학병원 영상의학과에서 경직장초음파 검사를 시행한 환자들이다. 총 418명의 성인남성 중 전립선암으로 확진된 13명을 제외한 405명을 대상으로 다음과 같은 결과를 얻었다. 전립선용적과 혈청 전립선특이항원은 연령이 증가함에 따라 함께 증가하는 것으로 나타났으나, 40대의 혈청 전립선특이항원 수치는 다른 연령집단에 비해 가장 낮은 것으로 나타났다. 연령과 전립선용적, 혈청 전립선특이항원은 통계적으로 유의한 양의 상관관계가 있는 것으로 나타났으며, 전립선용적과 혈청 전립선특이항원도 통계적으로 유의한 상관관계가 있는 것으로 나타났다. 이상의 결과를 정리해보면 연령과 전립선용적은 혈청 전립선특이항원의 변화에 관여하였으며, 특히 전립선용적은 연령보다 혈청 전립선특이항원 상승과 더 높은 연관성이 있는 것으로 나타났다. 이는 혈청 전립선 특이항원이 상승된 성인 남자의 평가에서 전립선용적이 중요하게 고려되어야 한다는 것을 시사하며, 경직장초음파검사는 전립선암을 진단하는 훌륭한 보조수단으로써 보다 적극적으로 경직장초음파검사를 활용한다면 전립선암을 조기에 진단하고 적절한 치료를 시행하는데 많은 도움을 줄 수 있을 것으로 생각되어진다.

• Journal of Microbiology
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• 제40권4호
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• pp.319-326
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• 2002

Cellular DNA in prokaryotes is organized in nucleic acid-protein self-assemblies referred to as the nucleoid. The physical forces responsible for its stability inside the poor solvent properties of the cytoplasm and their functional implications are not understood. Studies on the organisation and functioning of the cytosol of cells largely rely on experimental protocols performed in highly dilute solutions using biochemically purified molecules, which is not a reliable substitute for the situation existing in vivo. Our current research interest is focused on the characterization of biological and physical forces determining the compaction and phase separation of DNA in Escherichia coli cytoplasm. We have emphasized the effect of excluded volume in solutions with high macromolecular concentrations (macromolecular crowding) upon self-association patterns of reactions. The prokaryotic cytosol was simulated by addition of inert polymer polyethylene glycol (PEG) (average molecular weight 20000), as an agent which afterwards facilitates the self-association of macromolecules. Fluorescence microscopy was used for direct visualization of nucleoids in intact cells, after staining with DAPI (4',6-diamidino-2-phenylindole dihydrochloride). Addition of the crowding agent PEG 20,000, in increasing concentrations generated progressively enhanced nucleoid compaction, the effect being stronger in the presence of 0.2 M NaCl and 5 mM MgCl$\_$2/. Under these conditions, the nucleoids were compacted to volumes of around 2 ㎛$\^$3/ or comparable sizes with that of living cells.

• 한국전기전자재료학회논문지
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• 제12권1호
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• pp.69-74
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• 1999

We have investigated that the high pretilt angle of the NLC, 4-n-pentyl-4-cyanobiphenyl (5CB), was observed on rubbed polythiophene (PTP) surfaces with alkyl chains with more than 10 carbon atoms; it is attributed to the surface-excluded volume effect by the alkyl chain lengths between the LCs and the PTP surfaces. Next, we investigated that the odd-even effect of the polar anchoring strength in 5CB on rubbed PTP surfaces with alkyl chain lengths has been successfully evaluated. The anchoring strength of 5CB for rubbed PTP surfaces with odd-number is weak compared with even-number up to the 6 carbon atoms in the alkyl chain; however, odd-number is strong compared with even-number above 7 carbon atoms. The weak anchoring strength of 5CB is approximately $1\times10^{-3} (J/m^2$) on rubbed PTP surface with 7 carbon atoms; it is relatively strong anchoring strength. Consequently, we conclude that the odd-even effects of the polar anchoring strength in NLCs are strongly related to the characteristics of the polymer and observed clearly for short alkyl chain lengths.

• 한국환경보건학회지
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• 제40권3호
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• pp.204-214
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• 2014

Objectives: Vehicular emissions are one of the main sources of air pollution in urban areas. Correlation analysis was conducted between air pollutants and traffic volume in order to identify causes of air pollution in Gwangju. Methods: Using traffic volumes and air quality monitoring data from 2002 to 2012 from nine stations (seven urban areas, two roadside areas), especially at three sites where traffic volumes were high, the correlation coefficients were obtained between air pollutants as PM-10 (particulate matter), $NO_2$, $SO_2$, CO and $O_3$ at the stations and traffic volumes near the air monitoring stations. Results: Due to traffic volume and distance between the station and the traffic road, concentrations of pollutants at roadside areas were higher than at urban areas, with the exception of $O_3$. The concentration of $O_3$ showed statistically significance with those of other gas materials as $NO_2$, $SO_2$, and CO in winter (p<0.001) and spring (p<0.05). During the period of October 7 to 20, 2012, excluding periods of yellow dust, smog and rainy season, the ratio of $NO/(NO+NO_2)$ showed the highest value 0.57 and 0.40 at Unam and Chipyeong of two roadside stations, followed by 0.35 at Nongseong with vehicular effects. The correlation coefficient between traffic volume and $O_3$, CO, $NO_2$ became higher when the data on mist and haze days were excluded, than when all hourly data were used in that period, at the three sites of Unam, Chipyeong, and Nongseong. Conclusions: Air quality showed a considerable effect from vehicles at roadside areas compared to in urban areas. Air pollutant diminishment strategies need to be aggressively adopted in order to protect atmospheric environment.

• Biomolecules & Therapeutics
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• 제18권3호
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• pp.308-315
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• 2010

Essential oil-excluded Artemisia princeps Pamp var Ssajuarissuk (AP) was fermented with Lactobacillus brevis K-1, which was isolated from cabbage Kimchi, and the anti-inflammatory effects of AP and fermented AP (FAP) on lipopolysaccharide (LPS)-induced inflammatory response in peritoneal macrophages were investigated. AP and FAP inhibited LPS-induced TNF-$\alpha$, IL-$1{\beta}$, COX-2, iNOS and COX-2 expression, as well as NF-${\kappa}B$ activation. AP and FAP also reduced ear thickness, inflammatory cytokine (TNF-$\alpha$, IL-$1{\beta}$ and IL-6) expression and NF-${\kappa}B$ activation with 12-O-tetradecanoylphorbol-13-acetate (TPA) induced dermatitis in mice. Furthermore, AP and FAP also reduced exudate volume, cell number, protein amount, inflammatory cytokines (TNF-$\alpha$, IL-$1{\beta}$ and IL-6) expression and NF-${\kappa}B$ activation in carrageenan-induced air pouch inflammation in mice. The inhibitory effects of FAP were more potent than those of non-fermented AP. Based on these findings, we propose that FAP can improve inflammatory diseases, such as dermatitis, by inhibiting the NF-${\kappa}B$ pathway.