• Journal of the Mineralogical Society of Korea
• /
• v.26 no.2
• /
• pp.101-110
• /
• 2013

Due to the large specific surface area and great reactivity toward environmental contaminants, nanocrystalline mackinawite (FeS) has been widely applied for the remediation of contaminated groundwater and soil. Furthermore, nanocrystalline FeS is rather thermodynamically stable against anoxic corrosion, and its reactivity can be regenerated continuously by the activity of sulfate-reducing bacteria. However, nanocrystalline mackinawite is prone to either spread out along the groundwater flow or cause pore clogging in aquifers by particle aggregation. Accordingly, this mineral should be modified for the application of permeable reactive barriers (PRBs). In this study, coating methods were investigated by which mackinawite nanoparticles were deposited on the surface of alumina or activated alumina. The amount of FeS coating was found to significantly vary with pH, with the highest amount occurring at pH ~6.9 for both minerals. At this pH, the surfaces of mackinawite and alumina (or activated alumina) were oppositely charged, with the resultant electrostatic attraction making the coating highly effective. At this pH, the coating amounts by alumina and activated alumina were 0.038 and 0.114 $mmol{\cdot}FeS/g$, respectively. Under anoxic conditions, arsenite sorption experiments were conducted with uncoated alumina, uncoated activated alumina, and both minerals coated with FeS at the optimal pH for comparison of their reactivity. Uncoated activated alumina showed the higher arsenite removal compared to uncoated alumina. Notably, the arsenite sorption capacity of activated alumina was little changed by the coating with FeS. This might be attributed to the abundance of highly reactive hydroxyl functional groups (${\equiv}$AlOH) on the surface of activated alumina, making the arsenite sorption by the coated FeS unnoticeable. In contrast, the arsenite sorption capacity of alumina was found to increase substantially by the FeS coating. This was due to the consumption of the surface hydroxyl functional groups on the alumina surface and the subsequent occurrence of As(III) sorption by the coated FeS. Alumina, on the surface area basis, has about 8 times higher FeS coating amount and higher As(III) sorption capacity than silica. This study indicates that alumina is a better candidate than silica for the coating of nanocrystalline mackinawite.

• Journal of Korean Society for Atmospheric Environment
• /
• v.34 no.4
• /
• pp.567-587
• /
• 2018

A severe haze event occurred in October 2015 in Gwangju, Korea. In this study, the driving chemical species and the formation mechanisms of $PM_{2.5}$ pollution were investigated to better understand the haze event. Hourly concentrations of $PM_{2.5}$, organic and elemental carbon, water-soluble ions, and elemental constituents were measured at the air quality intensive monitoring station in Gwangju. The haze event occurred was attributed to a significant contribution (72.3%) of secondary inorganic species concentration to the $PM_{2.5}$, along with the contribution of organic aerosols that were strongly attributed to traffic emissions over the study site. MODIS images, weather charts, and air mass backward trajectories supported the significant impact of long-range transportation (LTP) of aerosol particles from northeastern China on haze formation over Gwangju in October 2015. The driving factor for the haze formation was stagnant atmospheric flows around the Korean peninsula, and high relative humidity (RH) promoted the haze formation at the site. Under the high RH conditions, $SO{_4}^{2-}$ and $NO_3{^-}$ were mainly produced through the heterogenous aqueous-phase reactions of $SO_2$ and $NO_2$, respectively. Moreover, hourly $O_3$ concentration during the study period was highly elevated, with hourly peaks ranging from 79 to 95ppb, suggesting that photochemical reaction was a possible formation process of secondary aerosols. Over the $PM_{2.5}$ pollution, behavior and formation of secondary ionic species varied with the difference in the impact of LTP. Prior to October 19 when the influence of LTP was low, increasing rate in $NO_3{^-}$ was greater than that in $NO_2$, but both $SO_2$ and $SO{_4}^{2-}$ had similar increasing rates. While, after October 20 when the impact of haze by LTP was significant, $SO{_4}^{2-}$ and $NO_3{^-}$ concentrations increased significantly more than their gaseous precursors, but with greater increasing rate of $NO_3{^-}$. These results suggest the enhanced secondary transformation of $SO_2$ and $NO_2$ during the haze event. Overall, the result from the study suggests that control of anthropogenic combustion sources including vehicle emissions is needed to reduce the high levels of nitrogen oxide and $NO_3{^-}$ and the high $PM_{2.5}$ pollution occurred over fall season in Gwangju.

• Proceedings of the Korean Biophysical Society Conference
• /
• 2003.06a
• /
• pp.80-80
• /
• 2003

${\beta}$-lapachone(${\beta}$-Lap), a natural o-naphthoquinone, presents in the bark of the Lapacho tree. ${\beta}$-Lap is cytotoxic against a variety of human cancer cells and it potentiates the anti-tumor effect of Taxol. In addition, ${\beta}$-Lap has been reported to radiosensitize cancer cells by inhibiting the repair of radiation-induced DNA damage.In the present study, we investigated the cytotoxicity of ${\beta}$-Lap against RKO human colorectal cancer cells as well as the combined effect of ${\beta}$-LaP and ionizing radiation. An incubation of RKO cells with 5 ${\mu}$M of ${\beta}$-Lap for 4 h killed almost 90％ of the clonogenic cells. An incubation of RKO cells with 5 ${\mu}$M of ${\beta}$-Lap for 4 h or longer also caused massive apoptosis. Unlike other cytotoxic agents, ${\beta}$-Lap did not increase the expression of p53 and p21 and it suppressed the NFkB expression. The expression of Caspase 9 and 3 was minimally altered by ${\beta}$-Lap. Radiation and ${\beta}$-Lap acted synergistically in inducing clonogenic cell death and apoptosis in RKO cells when ${\beta}$-Lap treatment was applied after but not before the radiation exposure of the cells. Interestingly, a 4 h treatment with 5 ${\mu}$M of ${\beta}$-Lap starting 5 h after irradiation was as effective as that starting immediately after irradiation. The mechanisms of ${\beta}$-Lap-induced cell killing is controversial but a recent hypothesis is that ${\beta}$-Lap is activated by NAD(P)H: quinone-onidoreductase (NQO1) in the cells followed by an elevation of cytosolic Ca$\^$2+/ level and activation of proteases leading to apoptosis. It has been reported that NQO1 level in cells is markedly up-regulated for longer than 10 h after irradiation. Indeed, using immunological staining of NQO1, we observed a significant elevation of NQO1 expression in RKO cells 5h after 2-4 Gy irradiation. Such a prolonged elevation of NQO1 level after irradiation may be the reasons why the ${\beta}$-Lap treatment applied S h after irradiation was as effective as that applied immediately after irradiation in killing the cells. In view of the fact that the repair of radiation-induced damage is usually completed within 1-2 h after irradiation, it is highly likely that the ${\beta}$-Lap treahment applied 5 h after irradiation could not inhibit the repair of radiation-induced damage. For in vivo study, RKO cells were injected S.C. into the hind-leg of Nu/Nu mice, and allowed to grow to 130 mm3 tumor. The mice were i.p. injected with ${\beta}$-lapachone or saline 2 h after irradiation of tumors with 10 Gy of X-rays. The radiation induced growth delay was increased by 2.4 $\mu\textrm{g}$/g of ${\beta}$-lapachone. Taken together, we may conclude that the synergistic interaction of radiation and ${\beta}$-Lap in killing cancer cells is not due to radiosensitization by ${\beta}$-Lap but to an enhancement of ${\beta}$-Lap cytotoxicity by radiation through an upregulation of NQO1. The fact that NQO1 is elevated in tumors and that radiation causes prolonged increase of the NQO1 expression may be exploited to preferentially kill tumor cells using ${\beta}$-Lap in combination with radiotherapy.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.40 no.9
• /
• pp.1208-1214
• /
• 2011

Caffeine, a psychoactive stimulant, has been implicated in the modulation of learning and memory functions due to its action as a non-selective adenosine receptors antagonist. On the contrary, some side effects of caffeine have been reported, such as an increased energy loss and metabolic rate, decrease DNA synthesis in the spleen, and increased oxidative damage to exerted on LDL particles. Therefore, the aim of this study was to develop a safe stimulant from natural plants mixture (Aralia elata, Acori graminei Rhizoma, Chrysanthemum, Dandleion, Guarana, Shepherd's purse) that can be used as a substitute for caffeine. Thirty SD rats were divided into three groups; control group, caffeine group (15.0 mg/kg, i.p.), and natural plants mixture group (NP, 1 mL/kg, p.o.). The effect of NP extract on stimulant activity was evaluated with open-field test (OFT) and plus maze test for measurement of behavioral profiles. Plasma lipid profiles, lipid peroxidation in LDL (conjugated dienes), total antioxidant capacity (TRAP) and DNA damage in white blood, liver, and brain cells were measured. In the OFT, immobility time was increased significantly by acute (once) and chronic (3 weeks) supplementation of NP and showed a similar effect to caffeine treatment. Three weeks of caffeine treatment caused plasma lipid peroxidation and DNA damage in liver cells, whereas there were no changes in the NP group. NP group showed a higher plasma HDL cholesterol concentration compared to the caffeine group. The results indicate that the natural plants mixture had a stimulant effect without inducing oxidative stress.

• Journal of the Korean Society of Food Science and Nutrition
• /
• v.40 no.5
• /
• pp.625-634
• /
• 2011

Green tea seed coat (GTSC) was extracted with 100% ethanol for 4 hr and then fractionated with petroleum ether (PE), ethyl acetate (EtOAC) and butanol (BuOH). The EtOAC fraction showed the highest level in total phenol contents and the lowest level in nitric oxide (NO) production in LPS-stimulated RAW264.7 macrophage cell. Thus, this study was carried out to investigate the anti-inflammatory and its mechanisms of GTSC EtOAC fraction in LPS-stimulated RAW264.7 macrophage cell. GTSC EtOAC fraction contained EGC ($1146.48{\pm}11.01\;{\mu}g/g$), tannic acid ($966.99{\pm}32.24\;{\mu}g/g$), EC ($70.88{\pm}4.39\;{\mu}g/g$), gallic acid ($947.61{\pm}1.03\;{\mu}g/g$), caffeic acid ($37.69{\pm}1.46\;{\mu}g/g$), ECG ($35.46{\pm}3.19\;{\mu}g/g$), and EGCG ($15.53{\pm}0.09\;{\mu}g/g$) when analyzed by HPLC. NO production was significantly (p<0.05) suppressed in a dose-dependent manner with an $IC_{50}$ of $80.11\;{\mu}g$/mL. Also prostaglandin $E_2$ level was also inhibited in a dose-dependent manner. Moreover, iNOS protein expression was suppressed in dose-dependent manner but COX-2 gene expression was not affected. Total antioxidant capacity and glutathione (GSH) levels were enhanced more than the LPS-control. Expressions of antioxidative enzymes including catalase, GSH-reductase and Mn-SOD were elevated compared to LPS-control. Nuclear p65 level was decreased in the GTSC EtOAC fraction in a dose-dependent manner. These results indicate that GTSC EtOAC fraction inhibit oxidative stress and inflammatory responses through elevated GSH levels, antioxidative enzymes expressions and suppression of iNOS expression via NF-${\kappa}B$ down-regulation.

• Journal of Periodontal and Implant Science
• /
• v.36 no.1
• /
• pp.125-137
• /
• 2006

1. 목적 흡연은 치주질환의 주요한 위험 인자 중의 하나이다. 일반적으로 흡연자는 비흡연자보다 비외과적 및 외과적 치주치료에 대한 반응이 덜 효과적인 것으로 알려져 있다. 이 연구에서는 중등도의 만성 치주염이 존재하는 한국인 흡연자와 비흡연자를 대상으로 하여, 비외과적 치주치료인 치석 제거술과 치근 활택술을 시행한 후 6개윌 동안의 임상적 치유 반응을 비교해 보고자 하였다. 2. 방법 20명의 중등도 만성 치주염 환자(흡연자 10명, 비흡연자 10명)를 대상으로 치주낭 깊이(Probing Pocket Depth, PPD), 치은퇴축(GR), 치주탐침시 출혈유무(BOP), #16, 12, 24, 32, 36, 44의 치태지수(Plaque Index, Silness & $L{\"{o}}e$ 1964)를 임상변수로 측정하였다. 치주낭 깊이 (PD)와 치은퇴축(GR)은 전자 탐침(Florida $Probe^{(R)}$ Co. Gainesville, FL)을 이용하여 각 치아당 6군데를 측정하였다. 임상적 부착 수준(CAL)은 치주낭 깊이(PD)와 치은퇴축(GR)의 합으로 계산하였다. 초진시에 전악 임상 검사를 시행하였고, 초진시의 치주낭 깊이에 따라 조사 대상이 되는 치아 부위를 선정하였다. 치주적으로 건강한 부위 $(PD{\leq}3mm)$를 대조군인 1군으로 하고 치주낭 깊이가 4 mm를 초과하고 5 mm 미만인 부위를 2군, 5 mm 이상의 치주낭 깊이를 가지는 부위를 3군으로 설정하였다. 비외과적 치주치료인 치석 제거술, 치근 활택술과 구강위생 교육을 시행하였고 2개월(T1), 4개윌(T2), 6개윌(T3)에 선정된 해당 치아 부위에 대해 임상 재검사를 시행하였다. 3. 결과 BOP와 Plaque Index는 초진, 2, 4, 6개월에 흡연자와 비흡연자 간에 유의할 만한 차이가 없었으나 전반적으로 감소하는 경향이 나타났다. 대조군인 l군에 서는 흡연자와 비흡연자 간에 모든 시기에서 PD, GR, CAL에 유의할 만한 차이가 없었다. 치주낭 깊이가 4 mm를 초과하고 5 mm 미만인 2군에서는 비흡연자에서 6개월에 유의할 만한 치주낭 깊이 감소가 나타났으며, 4개월과 6개윌에 유의할 만한 부착수준의 증가가 관찰되었다(p<0.05). 치주낭 깊이가 5 mm이상인 3군에서는 비흡연자에서 치주낭 깊이 감소가 일관되게 더 많이 나타났으나 통계학적으로 유의할 만한 차이는 6개월째에서만 관찰되었다. 2군과 유사하게 치주낭 갚이 감소는 흡연자보다 비흡연자에서 0.6 mm 더 크게 나타났다. 부착수준의 획득은 2군에서는 4, 6개월째에, 3군에서는 6개월째에 비흡연자에서 유의하게 더 많이 일어났다. 초진시의 치주낭 깊이와 각 시기별 ${\Delta}PD$ 간의 상관관계에서는 치주낭 갚이가 5mm 이상인 3군에서 비흡연자의 경우 6개월째에 가장 강한 상관성이 나타났다($r_s=0.43$, p<0.05). 흡연자에서는 3군에서 어떠한 유의한 상관관계도 나타나지 않았다. 결론적으로 중등도 만성 치주염 환자를 대상으로 한 6개윌의 단기간 연구에서 비외과적 치주치료 후 흡연자에서 비흡연자보다 치주낭 깊이 감소의 개선과 부착수준의 획득이 더 적게 나타나 임상적 치유반응이 좋지 않음을 확인하였다. 이는 흡연이 숙주의 치유반응 부정적인 영향을 주기 때문으로 생각된다.

• Tuberculosis and Respiratory Diseases
• /
• v.55 no.4
• /
• pp.370-377
• /
• 2003

Background : Pneumocystis carinii pneumonia (PCP) is one of the most common cause of infection in patients with HIV infection. Recently, the incidence of PCP have been increasing in immunocompromised hosts without HIV infection. We compared the clinical characteristics of PCP between HIV infected and non-infected persons. Patients and Methods : We retrospectively reviewed the charts of 25 patients diagnosed as PCP from 1996 to 2002. Age, sex, underlying conditions, use of immunosuppressants, clinical courses, laboratory findings, treatment and prognosis were compared between HIV infected and non-infected persons. Results : Twenty-five patients with PCP were identified. 16 were HIV infected, and 9 were HIV non-infected. The mean age of overall patients was $43.4{\pm}13.2$ years. Underlying conditions in HIV non-infected persons were hematologic malignancy (7 cases), solid organ transplant (1 case), and autoimmune disease (1 case). Seven cases (77.8%) of HIV non-infected persons had a history of steroid use. Mean duration of symptoms was longer in HIV infected persons than in HIV non-infected persons, but it was not statistically significant. PaO2 was lower in HIV infected persons ($61.2{\pm}16.9$ mmHg vs. $65.4{\pm}15.4$), but it was not statistically significant. Chest X ray showed typical ground glass opacity in 12 cases (75%) of HIV infected persons and in 4 cases (44.4%) of HIV non-infected persons. Twelve cases (75%) of HIV infected persons were treated with steroid, as were 6 cases (66.7%) of HIV non-infected persons. Ventilator care was needed in 6 cases (37.5%) of HIV infected persons and in 2 cases (22.2%) of HIV non-infected persons. Mortality of HIV infected persons was 50%, and that of HIV non-infected persons was 11.1%. Conclusions : PCP showed some different clinical characteristics between HIV infected and non-infected persons. Prospective studies regarding the risk factors of PCP, prophylaxis, treatment and prognosis in HIV infected and non-infected persons are warranted.

• Journal of the Korean Geographical Society
• /
• v.40
• /
• pp.1-13
• /
• 1989

The brightness temperature from NOAA AVHRR CH 4 images was examined for the metropolitan Seoul area, the capital city of Korea, to detect the characteristics of the urban heat island for this study. Surface data from 21 meteorological stations were compared with the brightness temperatures Through computer enhancement techniques, more than 20 heat islands could be recognized in South Korea, with 1 km spatii resolution at a scale of 1: 200, 00O(Fig. 3, 4 and 6). The result of the analysis of AVHRR CH 4 images over the metropolitan Seoul area can be summerized as follows (1) The pattern of brightness temperature distribution in the metropolitan Seoul area shows a relatively strong temperature contrast between urban and rural areas. There is some indication of the warm brightness temperature zone characterrizing built-up area including CBD, densely populated residential district and industrial zone. The cool brightness temperature is asociaed with the major hills such as Bukhan-san, Nam-san and Kwanak-san or with the major water bodies such as Han-gang, and reservoirs. Although the influence of the river and reservoirs is obvious in the brightness temperauture, that of small-scaled land use features such as parks in the cities is not features such as parks in the cities is not apperent. (2) One can find a linerar relationshop between the brightenss temperature and air temperature for 10 major cities, where the difference between two variables is larger in big cities. Though the coefficient value is 0.82, one can estimate that factors of the heat islands can not be explained only by the size of the cities. The magnitude of the horizontal brightness temperature differences between urban and rural area is found to be greater than that of horizontal air temperature difference in Korea. (3) Also one can find the high heat island intensity in some smaller cities such as Changwon(won(Tu-r=9.0$^{\circ}$C) and Po-hang(Tu-r==7.1$^{\circ}$~)T. he industrial location quotient of Chang-won is the second in the country and Po-hang the third. (4) A comparision of the enhanced thermal infrared imageries in 1986 and 1989, with the map at a scale of 1:200, 000 for the meotropolitan Seoul area showes the extent of possible urbanization changes. In the last three years, the heat islands have been extended in area. zone characterrizing built-up area including (5) Although the overall data base is small, the data in Fig. 3 suggest that brightness tempeautre could ge utilized for the study on the heat island characteristics. Satellite observations are required to study and monitor the impact of urban heat island on the climate and environment on global scale. This type of remote sensing provides a meams of monitoring the growth of urban and suburban aeas and its impact on the environment.

• Tuberculosis and Respiratory Diseases
• /
• v.49 no.6
• /
• pp.774-779
• /
• 2000

Pseudomembranous colitis, although uncommon, is an important complication of antibiotics that is related to a variety of deleterious effects on the gastrointestinal tract. Rifampicin is one of the 1st line agents in the treatment of tuberculosis and a large number of patients are exposed to its potential adverse effects. We report upon a patient that had diarrhea due to pseudomembranous colitis after receiving antitubeculous medication, and which was probably caused by rifampicin. A 77-year-old man was admitted with diarrhea of three weeks duration. One month previously, he suffered from left pleuritic chest pain and left pleural effusion was noticed at chest X-ray. One week prior to the onset of diarrhea, he was started on empirically isoniazid, rifampicin, ethambutol and pyrazynamide as antituberculous medication. On admission, he complained of diarrhea, left pleuritic chest pain, dyspnea and sputum. On physical examination, breathing sound was decreased in the left lower lung field and bowel sound increased. Pleural biopsy revealed chronic granulomatous inflammation, which was compatible with tuberculosis, Sigmoidoscopy showed whitish to yellowish pseudomembrane with intervening normal mucosa, and his stool was positive for C.difficle toxin. He was diagnosed as pseudomembranous colitis and treated with oral metronidazole and vancomycin. The diarrhea did not recur after reinstitution of the anti-tuberculous medication without rifampicin inpatients with severe diarrhea receiving anti-tuberculous medication, rifampicin induced pseudomembranous colitis should be excluded.

• Tuberculosis and Respiratory Diseases
• /
• v.38 no.1
• /
• pp.16-24
• /
• 1991

Adenosine deaminase (ADA) is an enzyme which is essential for the differentiation of lymphoid cells, especially T-cells and ADA plays a role in the maturation of monocyte to macrophage. Therefore ADA levels are related to stimulation of cellular immunity. We have investigated the measurement of ADA activity in bronchoalveolar lavage fluid of the patients with active and inactive pulmonary tuberculosis and control group. The results obtained are as follows: 1) The ADA activity and corrected ADA activity from the BAL fluid in active tuberculosis group (Total Lavage ADA; $18.4{\pm}22.5\;mU$, Total Lavage ADA/Albumin; $2.45{\pm}1.61\;mU/mg$) were increased when compared with those in inactive tuberculosis (TL-ADA; $5.8{\pm}2.5\;mU$, TL-ADA/Alb; $1.83{\pm}O.53\;mU/mg$) and control (TL-ADA; $6.6{\pm}4.3\;mU$, TL-ADA/Alb; $1.62{\pm}0.60\;mU/mg$) groups. 2) The ADA activity and lavage ADA/serum ADA activity ratio in BAL fluid from the lesion site (TL-ADA; $42.9{\pm}42.3\;mU$, L-ADA/S-ADA; $0.53{\pm}0.32$) were increased when compared with those from the non-lesion site (TL-ADA; $12.5{\pm}11.2\;mU$, L-ADA/S-ADA; $0.29{\pm}0.12$)and normal side (TL-ADA; $12.7{\pm}11.0\;mU$, L-ADA/S-ADA; $0.34{\pm}0.27$) in active tuberculosis group. 3) The ADA activity in BAL fluid from far advanced group (TL-ADA; $62.5{\pm}30.3\;mU$) was increased when compared with those from the mild group (TL-ADA; $10.5{\pm}7.5\;mU$) and moderate advanced group (TL-ADA; $13.2{\pm}11.7\;mU$) in active tuberculosis. 4) The albumin level from the BAL fluid was correlated with the ADA activity (R=0.89). 5) The ADA activity recovered from the BAL fluid was correlated with the recovered lymphocyte percentage (R=0.60). In conclusion, the ADA activity from the BAL fluid in active tuberculosis group was increased when compared with that in inactive tuberculosis and control groups, especially from the lesion site. To evaluated the specificity of ADA determination for diagnosis of active tuberculosis, BAL must be done at lesion site of the diseased lung and the proper correcting material other than albumin must be chosen to correct the dilution factor of lavage fluid.