• The Korean Journal of Physiology and Pharmacology
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• 제11권2호
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• pp.65-70
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• 2007

Chinese herb medicines have traditionally been used to treat or alleviate the symptom of various diseases. The rationale for use of certain herbs to certain disorder is now getting unveiled by modern technology. In the present study, we investigated whether herb mix extract(HMX), which is alleged to be useful for gastric ulcer, protects stomach from oxidative stress. Rats were allowed to normal diet with and without HMX (1, 5, 10 mg/kg) for 30 days. To induce gastric ulcer, ethanol (75%, 1.5 ml) or acidified aspirin (100 mg/kg in 0.2 N HCl) was administered by oral route in 24 h-fasted rats and examined the gastric ulceration(bleeding) by measuring the size 1 h after the treatment. Results indicated the area of gastric bleeding was significantly less in HMX fed rats than in normal diet fed ones, and it was dependent on the duration and amount of HMX. To investigate the underlying mechanism by which HMX protects stomach from oxidative stress, expression of enzymes like heme oxygenase (HO), cyclooxygenase (COX), and inducible nitric oxide (iNOS) were investigated in MKN-74 cells, where aspirin or H. pylori was introduced. The results were compared with RAW 264.7 cells to check if there's cell specificities exist. The expression of HO-1 but not COX-2, iNOS was significantly increased by HMX. Furthermore, HO-1 inhibitor, SnPP IX reduced the HO-1 activity and reversed the survival rate in HMX-treated MKN-74 cells. There's no difference between RAW 264.7 cells and MKN-74 cells. We, thus, concluded that HMX is beneficial for protection from oxidative injury, and induction of HO-1 by HMX in gastric cells is, at least, responsible for protection from oxidative stress such as ethanol, aspirin and possibly H. pylori infection.

• 한국사회복지학
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• 제69권1호
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• pp.223-254
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• 2017

본 연구는 기혼자의 결혼불만족이 외로움을 통해 SNS중독에 미치는 매개효과가 연구 대상자가 지각하는 사회자본의 크기 및 구성 장면에 따라 차이를 보이는 지, 즉 조절된 매개효과를 나타내는 지 확인하고자 하였다. 연구대상은 전국 20~40대 성인 기혼 남 녀 714명이다. 온라인 전문 리서치회사에 자료 조사를 의뢰해 인구통계학적 비례에 따른 할당 표집을 기본으로 임의 선택의 과정을 거쳐, 연구자료를 수집하였다. 본 연구모형 검증을 위해 구조방정식을 사용한 조절된 매개효과 분석 절차를 따랐다. 주요 분석 결과는 다음과 같다. 첫째, 외로움은 기혼 성인의 결혼불만족과 SNS 중독 사이를 매개하는 것으로 확인되었다. 특히, 독립변수와 종속변수 간 관계가 비유의적인 것으로 나타나, 매개효과의 완전 혹은 부분 여부를 경쟁모형 비료를 통해 확인한 결과, $x^2$을 비롯한 다양한 적합도 지수가 상대적으로 양호한 완전매개 모형을 최종적으로 채택하였다. 둘째, 결혼불만족과 외로움, SNS 중독 간 매개모형에서 사회자본 크기가 조절된 매개효과를 나타냈다. 구체적인 경로를 살펴보면, 자신의 사회자본을 상대적으로 크게 인식하는 집단이 작게 인식하는 집단에 비해 외로움에서 SNS중독에 이르는 과정과 결혼불만족에서 SNS중독에 이르는 경로의 효과 크기를 더 크게 인식했다. 이와 함께, 사회자본 형태별로 비중 차이에 따른 조절된 매개효과도 확인했다. 즉, 사회자본의 형태를 면대면 그리고 SNS 장면으로 구분해 각각의 비중 차이에 따라 면대면 우세, SNS우세 집단으로 구분해 매개모형의 다집단분석을 실시한 결과 각 경로 간 효과크기에 차이가 나타났다. 자신의 사회자본이 면대면 보다는 SNS 온라인 상에 더 편중되었다고 느끼는 집단에서는 외로움이 SNS 중독에 미치는 영향을 더 크게 느끼는 것으로 나타났다. 이는 면 대 면과 SNS 사회자본 사이의 불균형이 결혼불만족과 외로움, SNS 중독 간의 관계에서 위험요인으로 작용함을 의미한다. 이러한 연구결과를 토대로 기혼 성인들의 SNS 중독에 대처하기 위한 정책적, 실천적 대응방안을 제언하였다.

• Toxicological Research
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• 제20권3호
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• pp.195-203
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• 2004

4-Tert-Octylphenol (OP) is a surfactant additive widely used in the manufacture of a variety of detergents and plastic products. OP can disrupt endocrine function in humans and animals. This study was carried out to obtain toxicokinetic parameters of OP in male Sprague-Dawley (SD) rats. Male rats were administered with OP by single oral application of 200 mg/kg body weight. Blood, urine and tissues samples were taken at several time intervals after administration. Analysis of samples for OP was performed by column-switching high performance liquid chromatography (HPLC). In addition, we exam-ined tissue distribution and accumulation of OP after single oral application of 50, 100, and 200 mg/kg, single intravenous injection of 1, 5 and 10 mg/kg or daily application of 50 mg/kg for 14 consecutive days. After single oral administration of 200 mg/kg, Cmax of 213 $\pm$ 123 ng/ml was reached within the first 1.3 hr (Tmax) in the plasma. AUC was calculated for 1,333$\pm$484 ngㆍhr/ml. The final elimination half-life of plasma was longer than that of urine, but urinary clearance was lower than oral. A very small fraction of OP (Fe < 0.0017%) was excreted in urine within 24 hr. These results indicated that the major excretion route of OP was not urine. The mean maximal tissue distribution of OP was obserbed at 6 hr after treatment and slowly decreased time-dependently. High OP concentrations were detected in fat at 24 hr. The OP in fat was slowly released with longer elimination half-life and lower clearance than that of other tissues. OP was not accumulated in the liver following single oral application but 14-day oral treatments resulted in two-fold accumulation. It was probably due to the saturation of detoxification pathways. On the other hand, the mRNA expression of cytochrome P450 isoforms except CYP2C11 was not affected by OP at any dose. The expression of CYP2C11 mRNA decreased in a dose-dependent manner. This result suggests that OP changes expression of the male-specific cytochrome P450 isoforms in rat liver, and these changes are closely related to the toxic and estrogenic effect of OP.

• Toxicological Research
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• 제26권4호
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• pp.275-283
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• 2010

Placenta transfer study in non-human primate (NHP) is one of the crucial components in the assessment of developmental toxicity because of the similarity between NHP and humans. To establish the method to determine placenta transfer in non-human primate, toxicokinetics of valproic acid (VPA), a drug used to treat epilepsy in pregnant women, were determined in pregnant cynomolgus monkeys. After mating, pregnancy-proven females were daily administered with VPA at dose levels of 0, 20, 60 and 180 mg/kg by oral route during the organogenesis period from gestation day (GD) 20 to 50. Concentrations of VPA and its metabolite, 4-ene-VPA, in maternal plasma on GDs 20 and 50, and concentrations of VPA and 4-ene-VPA in placenta, amniotic fluid and fetus on GD 50 were analyzed using LC/MS/MS. Following single oral administration of VPA to pregnant monkeys, concentrations of VPA and 4-ene-VPA were generally quantifiable in the plasma from all treatment groups up to 4-24 hours post-dose, demonstrating that VPA was absorbed and the monkeys were systemically exposed to VPA and 4-ene-VPA. After repeated administration of VPA to the monkeys, VPA was detected in amniotic fluid, placenta and fetus from all treatment groups, demonstrating that VPA was transferred via placenta and the fetus was exposed to VPA, and the exposures were increased with increasing dose. Concentrations of 4-ene-VPA in amniotic fluid and fetus were below the limit of quantification, but small amount of 4-ene-VPA was detected in placenta. In conclusion, pregnant monkeys were exposed to VPA and 4-ene-VPA after oral administration of VPA at dose levels of 20, 60 and 180 mg/kg during the organogenesis period. VPA was transferred via placenta and the fetus was exposed to VPA with dose-dependent exposure. The metabolite, 4-ene VPA, was not detected in both amniotic fluid and fetus, but small amount of 4-ene-VPA was detected in placenta. These results demonstrated that proper procedures to investigate placenta transfer in NHP, such as mating and diagnosis of pregnancy via examining gestational sac with ultrasonography, collection of amniotic fluid, placenta and fetus after Caesarean section followed by adequate bioanalysis and toxicokinetic analysis, were established in this study using cynomolugus monkeys.

• Journal of Pharmaceutical Investigation
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• 제31권4호
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• pp.265-271
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• 2001

In order to elucidate the influence of intestinal and hepatic first-pass effect on the pharmacokinetics of triflusal, the biotransformation of triflusal in the gastrointestinal tract and liver was designed. Moreover, we tried to establish an HPLC method applicable for bioassay and available to pharmacokinetics, not only with the simultaneous determination of triflusal and its active metabolite, 2-hydroxy-4-trifluoromethyl benzoic acid (HTB), but also with improving sensitivity. After the administration of triflusal (10 mg/kg) and HTB (10 mg/kg) into femoral vein, portal vein (only triflusal) and oral route (only triflusal), pharmacokinetic parameters were investigated from the plasma concentration-time profiles of triflusal and HTB in rats. An HPLC method was developed for the simultaneous determination of triflusal and HTB in rat plasma, urine and bile. The HPLC analysis was carried out using a C18 column and acetonitrile-methanol-water (25:10:65, v/v/v) as the mobile phase and UV detection at 234 nm. Furosemide was used as the internal standard. The calibration curves were linear over the concentration range $0.05-5.0\;{\mu}g/ml$ for triflusal and $0.2-200.0\;{\mu}g/ml$ for HTB with correlation coefficients greater than 0.999 and with intra-day or inter-day coefficients of variation not exceeding 10.0%. This assay procedure was applied to the study of metabolite pharmacokinetics of triflusal and HTB in rats. It was supposed that triflusal was almost metabolized in vivo because urinary and biliary excreted amounts of triflusal could be ignored as it was lower than 1.2% of the administered dose. According to the gastrointestinal and hepatic biotransformation pathways of triflusal, it was found that triflusal was hydrolyzed by about 5% in intestine and metabolized by about 53% in liver, and that the bioavailability of triflusal after oral administration of triflusal was 0.44, and also that the fraction of total elimination rate of triflusal which formed HTB in liver $(F_{mi},\;%)$ was about 98%. These results showed that triflusal was almost metabolized in liver, and the total elimination of triflusal in the body was dependent to the formation rate of HTB from triflusal in liver.

• 환경영향평가
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• 제20권4호
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• pp.497-507
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• 2011

This research studied human health risk assessment of benzene from industrial complexes of Chungcheong Province (Seosan industrial complex) and Jeonla Province (Iksan industrial complex and Yeosoo industrial complex). The residents near the industrial complexes areas can be often exposed to volatile organic compounds (e.g., benzene, toluene, xylenes) through a number of exposure pathways, including inhalation of the organic pollutant via various environmental matrices (air, water and soil), contaminated water, and soil intake. Benzene is well known to be a common carcinogenic and toxic compound that is produced from industrial and oil refinery complexes. In this study, a number of samples from water, air, and soil were taken from the residential settings and public school zones located near the industrial complex sites. Based on the carcinogenic risk assessment, the risk estimates were slightly above $10{\times}10^{-6}$ at all three industrial sites. According to deterministic risk assessment, inhalation was the most important route. The distribution of benzene in the environment would be dependent on vapor pressure, and the physical property influencing the extent of the potential risks. Non-carcinogenic risk assessment of benzene shows that the values of Hazard Index(HI) were much lower than 1.0 at all industrial complexes. Therefore, benzene was not a cause of concern in terms of non-carcinogenic risk posed to the residents near the sites. When compared to probabilistic risk assessment, the CTE(central tendency exposure) cancer risk values of deterministic risk assessment were close to the mean values predicted by the probabilistic risk assessment. The RME(reasonable maximum exposure) values fell within the range of 95% to 99.9% estimated by the probabilistic risk assessment. Since the values of carcinogenic risk assessment were higher than $10{\times}10^{-6}$, further detailed monitoring and refined risk assessment for benzene may be warranted to estimate more reliable and potential inhalation risks to receptors near the industrial complexes.

• 디지털융복합연구
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• 제15권9호
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• pp.487-495
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• 2017

본 연구는 직장인의 스트레스와 불안이 업무몰입 간의 관계에서 스마트폰 중독이 어떻게 매개역할을 하는지를 살펴보았다. 이를 위해 전국적인 조직을 가지고 있는 K공기업의 직원 329명으로부터 자료를 수집하였고, AMOS 구조모형방정식을 이용하여 분석하였다. 분석결과 첫째, 스트레스와 불안이 높을수록 스마트폰 중독에 직접적인 영향을 미치는 것으로 나타났다. 둘째, 스마트폰 중독은 업무몰입에 직접적인 영향요인으로 유의한 부적 관계를 나타냈다. 셋째, 스마트폰 중독은 스트레스와 불안, 업무몰입 간의 관계에서 매개역할을 하는 것으로 나타났다. 즉 스트레스와 불안이 높은 직장인일수록 스마트폰에 과도하게 의존하게 되고 이로 인해 업무몰입이 감소하는 것으로 확인되었다. 이에 직장인의 스마트폰 중독 문제를 예방하기 위해서는 직장에서도 올바른 스마트폰 사용에 대한 지침 마련이 필요하며, 중독수준에 따른 서비스 지원도 이루어져야한다. 또한 업무몰입을 향상시키기 위해서는 스트레스를 잘 관리할 수 있도록 기업복지적인 측면에서 관심과 적극적인 지원이 필요하다. 본 연구는 직장인들의 스마트폰 중독에 이르는 경로를 밝혔다는 점에서 정책적인 시사점을 갖는다.

• 대한화학회지
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• 제37권8호
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• pp.765-772
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• 1993

Flux인 $K_2MoO_4$와 섬유원료물질인 $K_2CO_3,\;TiO_2$를 혼합하고 1150$^{\circ}C$에서 용융시킨 다음 950$^{\circ}C$까지 서냉하여(서냉속도=5$^{\circ}C$/h) 층상구조를 갖는 사티탄산칼륨($K_2Ti_4O_9$)과 육티탄산칼륨($K_2Ti_6O_{13}$) 섬유를 합성하였다. Flux(F)와 출발원료물질(R)의 혼합비에 따른 최적 섬유성장 조건을 조사하기 위하여 F:R을 변화시키면서 반응시킨 결과 섬유의 결정상 및 성장속도가 F:R의 비에 크게 의존함을 알 수 있었으며 본 실험조건에서는 사티탄산칼륨과 육티탄산칼륨 모두 F:R=7:3 일 때 섬유의 성장이 가장 양호하였다. F:R = 7:3이고, 출발조성이 $K_2O{\cdot}4TiO_2$인 경우 생성물은 $K_2Ti_4O_9$과 약간의 $K_2Ti_6O_{13}$의 혼합상이 얻어졌으며 평균 섬유 길이는 ${\thickapprox}$ 4 mm 정도의 비교적 장섬유를 얻을 수 있었다. $K_2O{\cdot}6TiO_2$ 조성인 경우도 $K_2Ti_4O_9$의 혼합상이 형성되었고 섬유의 평균길이는 ${\thickapprox}$ 2 mm 정도임을 관찰할 수 있었다.

• 농약과학회지
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• 제3권2호
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• pp.54-59
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• 1999

제초제 metolachlor [2-chloro-6'-ethyl-N-(2-methoxy-1-methylethyl)aceto-O-toluidid]의 잉어체내 행적을 구명하기 위하여 $LC_{10}$(1.93 mg/L)으로 metolachlor를 처리한 시험수에 잉어를 경시적으로 노출시켰다. 수중의 metolachlor는 잉어 체내에 신속히 흡수 이행되어 노출 후 6시간에 최대 흡수량을 나타내었으며, 잉어에 흡수 이행된 metolachlor의 주요 배설경로는 담도이었다. 또한 잉어 체내에 흡수 이행된 방사능의 추출율이 처리 후 6시간까지 현저히 감소하여 잉어 체내에서 생성된 극성 대사산물이 잉어체내에서 접합체를 형성한 후추출이 불가한 결합잔류물을 형성하였음을 시사하였다. 시험수와 잉어 추출액중 방사능이 수상으로 분배된 양이 각각 처리후 12시간과 6시간에 가장 높았고 그 양도 각각 총처리 방사능의 약 14% 및 12%로써 metolachlor가 잉어 체내에서 신속히 대사될 가능성을 시사하였다.

• 한국언론정보학보
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• 제71권
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• pp.116-154
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• 2015

1987년 이후 광주민주화운동이라는 역사적 기표를 공식 부여받은 $5{\cdot}18$은 극우보수 집단에 의해 북한의 지령이나 북한과 연계된 불순분자들에 의한 내란과 폭동으로 재서술되고 있다. 내란과 반란, 폭동의 주범들이 보상을 받고 종북좌파가 득세하는 국가가 탄생했다고 주장하는 극우보수 집단의 서사는 $5{\cdot}18$을 향한 극단적 적대감을 고취시킨다. 정당, 대학, 언론, 시민단체 등에서 활동하는 극우보수 인사들이 $5{\cdot}18$의 역사와 기억을 자신들의 서사 속에서 재정립하려는 담화 정치를 수행한다. '일베'에서 '젊은 우파' 집단으로 평가받는 이들 또한 $5{\cdot}18$에 대한 극우보수 집단의 언설들을 지지하고 확산시킨다. '일베'는 극우보수 인사들의 언설과 $5{\cdot}18$ 관련 정보들의 재구성과 재생산의 주요한 통로다. '일베'는 $5{\cdot}18$에 대한 폄하와 조롱, 적대와 혐오의 언설들이 펼쳐지는 주된 무대 중 하나다. 이 논문에서는 '일베'에서 펼쳐지는 언설과 이야기들이 $5{\cdot}18$을 어떻게 의미화하고 있는지, 언설들이 의존하고 있는 정보 자원들은 무엇이며 서로 어떻게 연결되어 있는지 살펴보았다. 이를 통해 '일베'와 극우보수 집단에 의한 $5{\cdot}18$ 관련 언설들이 공명(共鳴)하면서 만들어 내는 역사의 내전화에 대해 살펴보고자 했다.