Journal of Korean Society of Environmental Engineers
/
v.29
no.4
/
pp.425-437
/
2007
Flow distribution of water and sedimentation rate were investigated to understand the hydrodynamics and settling characteristics of particulate materials in a constructed wetland for treatment of non-point sources pollutants, the Sihwa constructed wetland, Korea. The Sihwa constructed wetland is divided into three sub-wetlands(the Banwol, the Donghwa and the Samhwa wetlands) to treat the polluted water from three streams, the Banwol stream, the Donghwa stream and the Samhwa stream. From the results of water flow experiment using dye(Rhodamine 50WT Red), it was found that the water flow in the wetland was prevailing at the waterway and open water. Dye was spread slowly in the closed water area planted by plants. The mean hydraulic retention time(HRT) at the upper area of high wetland and lower wetland of Banwol, was found to be 34.1 hr at the upper area and 74.6 hr at the lower area respectively, totaling approximately 108.7 hr(4.5 days). The sedimentation rate was higher at lower area(sites of B, C and D) of the wetland than upper area(site of A which is settling zone). Based on the forecast for 20 years as to the amount of sediment that can be deposited in the open water in the future, the sediment depth of each area would be like this: A: 6.3 cm, B: 8.3 cm, C: 7.0 cm, D: 9.5 cm. The contents of organic materials in the sediment deposited within the sediment trap were found to be higher overly in the first investigation period which had much rainfall, and B, C and D areas were found to have an increased COD accumulation than A area. Also, nitrogen and phosphorus were found to increase in the down-stream of the wetland. The results of this study suggest that a sustainable research and management for the characteristics of water flow pattern and sedimentation changeable as time passes is needs to maintain or improve the efficiency of water treatment in the constructed wetland.
Shon, Hokyong;Okour, Yousef;Saliby, Ibrahim El;Park, Jun;Cho, Dong-Lyun;Kim, Jong Beom;Park, Hee Ju;Kim, Jong-Ho
Applied Chemistry for Engineering
/
v.20
no.3
/
pp.241-250
/
2009
During the past few years, titanium salts were investigated as alternative coagulants for the removal of organic matter of different molecular sizes in contaminated water. The flocculation efficiency of Ti-salt was comparable to those of $FeCl_3$ and $Al_2(SO_4)_3$ salts, commonly used coagulants. Incinerated sludge-$TiO_2$ showed higher surface area and photocatalytic activity than commercially available $TiO_2$. Metal-doped forms were produced by adding coagulant aids such as iron (Fe-), aluminium (Al-) and (Ca-) calcium salts during Ti-salt flocculation to increase pH. Ca- and Al- doped $TiO_2$ showed very high photocatalytic activity compared to Fe-doped $TiO_2$. When tested in a pilot scale plant for treatment of dye wastewater to check practical feasibility of the novel process, the removal ratio of the chemical oxygen demand was comparable to those of commonly used coagulants but the settling of sludge was faster. The $TiO_2$ generated after sludge incineration showed a high photocatalytic activity for degradation of volatile organic compounds and increased the rate of hydrogen production by water photosplitting. $TiCl_4$ coagulant and $TiO_2$ produced from different water sources with different concentrations had low acute toxicity compared to heavy metals and commercial $TiO_2$ when examined based on D. Magna mortality. This paper presents the production, characterisation and the photoactivity of $TiO_2$ produced from Ti-salt flocculated sludge. Different case studies are discussed to highlighted recent advances in this field.
A total of 29 eyes (25 dogs: one eye, 2 dogs: both eyes) with indolent corneal ulcer were treated with grid keratotomy from January 2008 to March 2010. The corneal lesions were reevaluated at 7-14 day intervals. The treatments had been repeated until fluorescein dye was not retained on the cornea and the epithelium did not appear to be loosely attached to the stromal layer. The healing rate of the corneal ulcers was 86.2%. The mean healing time ($mean{\pm}SD$) was $15.92{\pm}9.19$ days, ranged from 7 to 39 days. The lesions of remaining 4 eyes had deteriorated or not improved for more than 6 weeks. In those cases, $3^{rd}$ eyelid flap following grid keratotomy was applied. After 2 weeks, all of the eyes healed by the treatment. The results in this study suggest that grid keratotomy could be an excellent choice as an initial treatment for superficial corneal ulcers in dogs. In the cases of recurrence or to promote healing of the lesions, however, $3^{rd}$ eyelid flap following grid keratotomy is recommended.
Intracellular ions which have a major role in cellular function have been reported to affect repair of radiation damage. Recently it has been reported that ouabain sensitizes A549 tumor cellls but not CCL-120 normal cells to radiation. Ouabain inhibits the $Na^+-K^+$-pump rapidly thus it increases intracellular Na concentration, Vanadate which is distributed extensively in almost all living organisms is known to be a $Na^+-K^+$-ATPase inhibitors, This study was performed to see any change in radiosensitivity of tumor cell by vanadate and any role of $Na^+-K^+$ATPase in radiosensitization. Experiments have been carried out by pretreatment with vanadate in human cell line(A549, JMG) and mouse cell line(L1210, spleen). For the cell survival MTT assay was performed for A549 and JMC cells and frypan blue dye exclusion test for L120, and spleen cells. Measurements of $Na^+-K^+$-ATPase activity in control, vanadate treated cell, radiation treated cell (9 Gy for A549 and JMG, 2 Gy for L1201, spleen), and combined $10^{-6}M$ vanadate and radiation treated cells were done. The results were summerized as fellows. 1. L1210 cell was most radiosensitive, and spleen cell and JMG cell were intermediate, and A549 cell was least radiosensitive. 2. Mininum or no cytotoxicity was seen with vanadate below concentration of $10^{-6}M$. 3. In A549 cells there was a little change in radiosensitivity with treatment of vanadate. However radiation sensitization was shown in low dose level of radiation i. e. 2- Gy. In JMG cells no change in radiosensitivity was noted. Both L1210 and spleen cell had radiosensitization but change was greater in tumor cell. 4. $Na^+-K^+$-ATPase activity was inhibited significantly in tumor cell by treatment of vanadate. 5. Radiaiton itself inhibited $Na^+-K^+$-ATPase activity of tumor cell with high $Na^+-K^+$-ATPase concention. Increase in radiosensitivity by vanadate was closely associated with orginal $Na^+-K^+$-ATPase contents. From the above results vanadate had little cytotoxicity and it sensitized tumor cells to radiation. Inhibitory effect of vanadate on $Na^+-K^+$-ATPase activity might be one of the contributing factors for radiosensitization to tumor cells which has greater enzyme activity than that of normal cell. It was suggested vanadate could be used as a potential radiosensitizer for tumor cells.
The proteins of the ruminant erythrocyte membranes were analysed by polyacrylamide gel electrophoresis in sodium dodecyl sulfate, and their relations to the slow erythrocyte sedimentation rate(ESR) of the ruminants were investigated by treating the erythrocytes with proteinases such as trypsin, chymotrypsin and pronase, and glycosidases such as neuraminidase and galactosidase. Protein content in the erythrocyte membrane was $2.85{\pm}0.28$ in human, $3.60{\pm}0.41$ in Korean cattle, $3.71{\pm}0.36$ in Holstein, $4.13{\pm}0.83$ in Korean native goat and $3.94{\pm}0.56mg/ml$ in sheep, showing higher in ruminant animals than in human(p<0.01). Although the general protein profiles of the ruminant erythrocyte membranes were almost similar to that of human, all the ruminant erythrocyte membranes showed one additional protein band, called band-Q in the previous report on proteins of bovine erythrocyte membrane, which migrated electrophoretically to the mid position between band-2 and band-3 in human erythrocyte membranes. The glycoprotein profiles of ruminant erythrocyte membranes revealed by periodic acid Schiff(PAS) stain showed a marked difference from that of human. The PAS-1(glycophorin) and PAS-2(sialoglycogrotein) present in human erythrocyte membranes were almost absent from the ruminant animals. Instead, a strong PAS-positive band near the origin of the electrophorograms, which was named as PAS-B in the previous report on proteins of bovine erythrocyte membranes, was shown in the ruminant animals except sheep. In addition, the erythrocyte membranes of Korean native goat and sheep showed a moderate PAS-negative band near the tracking dye of the electrophorograms, which was named as PAS-G in this study. In the erythrocyte treated with the enzymes, the migration of each protein fracture of erythrocyte membranes in response to each enzyme was diverse according to different species or breed of ruminant animals. Among others, band-Q present in ruminants was slightly or moderately decreased by trypsin-, chymotrypsin-, and pronase- treatments of the erythrocytes, but not only in sheep. It was particularly noticeable that PAS-B, a fraction of glycoprotein, present in ruminants except sheep, was better digested by proteinases than by glycosidases, showing remarkable increase(p<0.01) of the ESR in accord with complete digestion(disappearance) of the PAS-B band by pronase, trypsin or chymotrypsin treatment of erythrocytes. In sheep, there was almost no any response to the various enzymes in general protein and glycoprotein profiles of the erythrocyte membranes except PAS-G, which was markedly decreased by pronase treatment of the erythrocytes. Nevertheless, the ESRs were accelerated in erythrocytes treated with pronase, trypsin, chymotrypsin and neuraminidase. Erythrocyte osmotic fragility was increased in erythrocytes treated with only pronase among five enzymes in all the human and ruminant animals used in this study.
We have studied the effect of heat treatment of multi-walled carbon nanotubes (MWNTs) as a counter electrode on the electro-chemical properties of dye-snsitized solar cells. MWNTs on the p-type Si substrate were synthesized by thermal chemical vapor deposition (CVD) using Fe catalysts. We prepared the two types of MWNTs samples with the different diameters. The rapid thermal annealing (RTA) treatment for the MWNTs was carried out at the growth temperature ($900^{\circ}C$) for 1 minute with $N_2$ gas atmosphere. The structural, electrical and electrochemical properties of MWNTs were investigated by field-emission scanning electron microscopy (FE-SEM), Raman spectroscopy, 2-point probe station and electrochemical impedance spectroscopy (EIS). The I(D)/I(G) ratio of heat-treated MWNTs in Raman spectra was considerably decreased. It was also found that the heat-treated MWNTs showed better redox reaction of iodide at the interface between MWNTs surface and electrolyte than that of as-grown MWNTs. The redox resistance value of heat-treated electrodes was measured to be much lower than that of as-grown electrode at the interface. As a result, the counter electrode using the heat-treated MWNTs showed better electrochemical properties.
Park, Dong-Il;Jeong, Jin-Woo;Park, Cheol;Hong, Su-Hyun;Shin, Soon-Shik;Choi, Sung-Hyun;Choi, Yung-Hyun
Herbal Formula Science
/
v.23
no.2
/
pp.199-208
/
2015
Objectives : In the present study, we investigated the effects of ethanol extract of Scutellaria baicalensis (EESB) on the progression of cell cycle in human renal cell carcinoma Caki-1 cells. Methods : The effects of EESB on cell growth and apoptosis induction were evaluated by trypan blue dye exclusion assay and flow cytometry, respectively. The mRNA and protein levels were determined by Western blot analysis and reverse transcription-polymerase chain reaction, respectively. Results : It was found that EESB treatment on Caki-1 cells resulted in a dose-dependent inhibition of cell growth and induced apoptotic cell death as detected by Annexin V-FITC staining. The flow cytometric analysis indicated that EESB resulted in G2/M arrest in cell cycle progression which was associated with the down-regulation of cyclin A expression. Our results also revealed that treatment with EESB increased the mRNA and proteins expression of tumor suppressor p53 and cyclin-dependent kinase (Cdk) inhibitor p21(WAF1/CIP1), without any noticeable changes in cyclin B1, Cdk2 and Cdc2. In addition, the incubation of cells with EESB resulted in a significant increase in the binding of p21 and Cdk2 and Cdc2. These findings suggest that EESB-induced G2/M arrest and apoptosis in Caki-1 cells is mediated through the p53-mediated upregulation of Cdk inhibitor p21. Conclusions : Taken together, these findings suggest that EESB may be a potential chemotherapeutic agent and further studies will be needed to identify the biological active compounds that confer the anti-cancer activity of S. baicalensis.
Journal of Korean Society of Environmental Engineers
/
v.22
no.6
/
pp.1149-1158
/
2000
A radioisotope tracer experiment was carried out in the submerged fixed bioreactor of a dye wastewater treatment facility to evaluate the flow behaviors in the 6 compartments of the reactor and to find any possible factors which may affect to the efficiency of the process. Approximately 20mCi of $^{131}I$ was injected into the system as a tracer and 8 radiation detectors were placed in the 6 compartments and at the inlet and the outlet of the system to measure the change of the tracer concentration with time. Using the Perfect Mixers in Series Model the measured data were analyzed to calculate the mean residence time and the characteristic parameters of the flow in the system. The mean residence time of the system was calculated as 17 hours which is 76% of the designed MRT(22.3hr). Among the 6 compartments, the first compartment doesn't show the characteristic of perfect mixer, whereas, the other 5 compartments are working as perfect mixers. The output response of the first compartment is fit well with the simulated output of a model which consists of a perfect mixer with an exchange volume. It indicates that a quarter of the tank volume is working as a dead volume or an exchange volume. From the measured residence time distributions in each compartment, the appropriate sampling times after the change of operational condition of the electron beam accelerator were evaluated.
Blue light with strong energy is required for light-curing resin treatment, which is being used more frequently in dentistry. To reduce the risk of exposure to scattered light, we tried to use colored lenses. The tips for light curing machine and a commercially available yellow-type blue-light blocking lens and a yellow lens colored with yellow dye, which are expected to be effective in blocking blue light, were placed in a UV-Vis spectrometer device, and transmission and blocking of blue light were tested respectively. As a result, the average blue light blocking rate of the light curing machine tips was 99.49%, and the C lens with the highest color density among commercially available lenses showed a high blue light blocking rate of 99.54%. In the case of lenses tinted with yellow, the yellow tinted C lens with the highest tint concentration showed 87.57% of blue light blocking rate. It is judged that the side effects related to the eyes caused by blue light can be reduced if a yellow-type commercially available or colored lens is worn along with a light curing machine tip during resin treatment.
Purpose: Cancer is the leading cause of death in Koreans, with breast cancer being the most common among women. Breast cancer readily metastasizes, and the existing treatment processes impose a significant burden on patients. This study examined whether pomegranate-derived exosome-like nanovesicles (PNVs) have anti-cancer effects by inhibiting cell infiltration and metastasis while increasing apoptosis on breast cancer MDA-MB-231 cells. Methods: Initially, exosome-like nanovesicles were isolated from pomegranate using ultracentrifugation. Subsequently, the size range of these nanovesicles was confirmed using nanoparticle tracking analysis. The ability of breast cancer MDA-MB-231 cells to internalize these natural nanovesicles was assessed with flourescence microscope. The anti-cancer effects of the PNVs were confirmed by applying various concentrations of PNVs (10, 50, 100 ㎍/mL) to MDA-MB-231 cells and systematically assessing their impact on cell viability and migration. Results: The round shape of the lipid bilayer in the PNVs was confirmed, providing crucial insights into their structural properties. We demonstrate that PNVs-associated DiD dye can be efficiently internalized by the MDA-MB-231 cells. The data showed that the PNVs inhibited cell viability, invasion rates, and migration in MDA-MB-231 cells. In addition, PNVs were absorbed into the MDA-MB-231 cells, leading to an increased expression of apoptosis proteins, such as cleaved caspase-3 and phosphorus-JNK, in a concentration-dependent manner. Furthermore, a reduction in cell infiltration and decreased expression of the transition markers MMP-2 and MMP-9 proteins were observed. Conclusion: For the first time, this study suggests that PNVs may be useful in the prevention or treatment of breast cancer by inhibiting the infiltration and metastasis of MDA-MB-231 cells and inducing apoptosis.
본 웹사이트에 게시된 이메일 주소가 전자우편 수집 프로그램이나
그 밖의 기술적 장치를 이용하여 무단으로 수집되는 것을 거부하며,
이를 위반시 정보통신망법에 의해 형사 처벌됨을 유념하시기 바랍니다.
[게시일 2004년 10월 1일]
이용약관
제 1 장 총칙
제 1 조 (목적)
이 이용약관은 KoreaScience 홈페이지(이하 “당 사이트”)에서 제공하는 인터넷 서비스(이하 '서비스')의 가입조건 및 이용에 관한 제반 사항과 기타 필요한 사항을 구체적으로 규정함을 목적으로 합니다.
제 2 조 (용어의 정의)
① "이용자"라 함은 당 사이트에 접속하여 이 약관에 따라 당 사이트가 제공하는 서비스를 받는 회원 및 비회원을
말합니다.
② "회원"이라 함은 서비스를 이용하기 위하여 당 사이트에 개인정보를 제공하여 아이디(ID)와 비밀번호를 부여
받은 자를 말합니다.
③ "회원 아이디(ID)"라 함은 회원의 식별 및 서비스 이용을 위하여 자신이 선정한 문자 및 숫자의 조합을
말합니다.
④ "비밀번호(패스워드)"라 함은 회원이 자신의 비밀보호를 위하여 선정한 문자 및 숫자의 조합을 말합니다.
제 3 조 (이용약관의 효력 및 변경)
① 이 약관은 당 사이트에 게시하거나 기타의 방법으로 회원에게 공지함으로써 효력이 발생합니다.
② 당 사이트는 이 약관을 개정할 경우에 적용일자 및 개정사유를 명시하여 현행 약관과 함께 당 사이트의
초기화면에 그 적용일자 7일 이전부터 적용일자 전일까지 공지합니다. 다만, 회원에게 불리하게 약관내용을
변경하는 경우에는 최소한 30일 이상의 사전 유예기간을 두고 공지합니다. 이 경우 당 사이트는 개정 전
내용과 개정 후 내용을 명확하게 비교하여 이용자가 알기 쉽도록 표시합니다.
제 4 조(약관 외 준칙)
① 이 약관은 당 사이트가 제공하는 서비스에 관한 이용안내와 함께 적용됩니다.
② 이 약관에 명시되지 아니한 사항은 관계법령의 규정이 적용됩니다.
제 2 장 이용계약의 체결
제 5 조 (이용계약의 성립 등)
① 이용계약은 이용고객이 당 사이트가 정한 약관에 「동의합니다」를 선택하고, 당 사이트가 정한
온라인신청양식을 작성하여 서비스 이용을 신청한 후, 당 사이트가 이를 승낙함으로써 성립합니다.
② 제1항의 승낙은 당 사이트가 제공하는 과학기술정보검색, 맞춤정보, 서지정보 등 다른 서비스의 이용승낙을
포함합니다.
제 6 조 (회원가입)
서비스를 이용하고자 하는 고객은 당 사이트에서 정한 회원가입양식에 개인정보를 기재하여 가입을 하여야 합니다.
제 7 조 (개인정보의 보호 및 사용)
당 사이트는 관계법령이 정하는 바에 따라 회원 등록정보를 포함한 회원의 개인정보를 보호하기 위해 노력합니다. 회원 개인정보의 보호 및 사용에 대해서는 관련법령 및 당 사이트의 개인정보 보호정책이 적용됩니다.
제 8 조 (이용 신청의 승낙과 제한)
① 당 사이트는 제6조의 규정에 의한 이용신청고객에 대하여 서비스 이용을 승낙합니다.
② 당 사이트는 아래사항에 해당하는 경우에 대해서 승낙하지 아니 합니다.
- 이용계약 신청서의 내용을 허위로 기재한 경우
- 기타 규정한 제반사항을 위반하며 신청하는 경우
제 9 조 (회원 ID 부여 및 변경 등)
① 당 사이트는 이용고객에 대하여 약관에 정하는 바에 따라 자신이 선정한 회원 ID를 부여합니다.
② 회원 ID는 원칙적으로 변경이 불가하며 부득이한 사유로 인하여 변경 하고자 하는 경우에는 해당 ID를
해지하고 재가입해야 합니다.
③ 기타 회원 개인정보 관리 및 변경 등에 관한 사항은 서비스별 안내에 정하는 바에 의합니다.
제 3 장 계약 당사자의 의무
제 10 조 (KISTI의 의무)
① 당 사이트는 이용고객이 희망한 서비스 제공 개시일에 특별한 사정이 없는 한 서비스를 이용할 수 있도록
하여야 합니다.
② 당 사이트는 개인정보 보호를 위해 보안시스템을 구축하며 개인정보 보호정책을 공시하고 준수합니다.
③ 당 사이트는 회원으로부터 제기되는 의견이나 불만이 정당하다고 객관적으로 인정될 경우에는 적절한 절차를
거쳐 즉시 처리하여야 합니다. 다만, 즉시 처리가 곤란한 경우는 회원에게 그 사유와 처리일정을 통보하여야
합니다.
제 11 조 (회원의 의무)
① 이용자는 회원가입 신청 또는 회원정보 변경 시 실명으로 모든 사항을 사실에 근거하여 작성하여야 하며,
허위 또는 타인의 정보를 등록할 경우 일체의 권리를 주장할 수 없습니다.
② 당 사이트가 관계법령 및 개인정보 보호정책에 의거하여 그 책임을 지는 경우를 제외하고 회원에게 부여된
ID의 비밀번호 관리소홀, 부정사용에 의하여 발생하는 모든 결과에 대한 책임은 회원에게 있습니다.
③ 회원은 당 사이트 및 제 3자의 지적 재산권을 침해해서는 안 됩니다.
제 4 장 서비스의 이용
제 12 조 (서비스 이용 시간)
① 서비스 이용은 당 사이트의 업무상 또는 기술상 특별한 지장이 없는 한 연중무휴, 1일 24시간 운영을
원칙으로 합니다. 단, 당 사이트는 시스템 정기점검, 증설 및 교체를 위해 당 사이트가 정한 날이나 시간에
서비스를 일시 중단할 수 있으며, 예정되어 있는 작업으로 인한 서비스 일시중단은 당 사이트 홈페이지를
통해 사전에 공지합니다.
② 당 사이트는 서비스를 특정범위로 분할하여 각 범위별로 이용가능시간을 별도로 지정할 수 있습니다. 다만
이 경우 그 내용을 공지합니다.
제 13 조 (홈페이지 저작권)
① NDSL에서 제공하는 모든 저작물의 저작권은 원저작자에게 있으며, KISTI는 복제/배포/전송권을 확보하고
있습니다.
② NDSL에서 제공하는 콘텐츠를 상업적 및 기타 영리목적으로 복제/배포/전송할 경우 사전에 KISTI의 허락을
받아야 합니다.
③ NDSL에서 제공하는 콘텐츠를 보도, 비평, 교육, 연구 등을 위하여 정당한 범위 안에서 공정한 관행에
합치되게 인용할 수 있습니다.
④ NDSL에서 제공하는 콘텐츠를 무단 복제, 전송, 배포 기타 저작권법에 위반되는 방법으로 이용할 경우
저작권법 제136조에 따라 5년 이하의 징역 또는 5천만 원 이하의 벌금에 처해질 수 있습니다.
제 14 조 (유료서비스)
① 당 사이트 및 협력기관이 정한 유료서비스(원문복사 등)는 별도로 정해진 바에 따르며, 변경사항은 시행 전에
당 사이트 홈페이지를 통하여 회원에게 공지합니다.
② 유료서비스를 이용하려는 회원은 정해진 요금체계에 따라 요금을 납부해야 합니다.
제 5 장 계약 해지 및 이용 제한
제 15 조 (계약 해지)
회원이 이용계약을 해지하고자 하는 때에는 [가입해지] 메뉴를 이용해 직접 해지해야 합니다.
제 16 조 (서비스 이용제한)
① 당 사이트는 회원이 서비스 이용내용에 있어서 본 약관 제 11조 내용을 위반하거나, 다음 각 호에 해당하는
경우 서비스 이용을 제한할 수 있습니다.
- 2년 이상 서비스를 이용한 적이 없는 경우
- 기타 정상적인 서비스 운영에 방해가 될 경우
② 상기 이용제한 규정에 따라 서비스를 이용하는 회원에게 서비스 이용에 대하여 별도 공지 없이 서비스 이용의
일시정지, 이용계약 해지 할 수 있습니다.
제 17 조 (전자우편주소 수집 금지)
회원은 전자우편주소 추출기 등을 이용하여 전자우편주소를 수집 또는 제3자에게 제공할 수 없습니다.
제 6 장 손해배상 및 기타사항
제 18 조 (손해배상)
당 사이트는 무료로 제공되는 서비스와 관련하여 회원에게 어떠한 손해가 발생하더라도 당 사이트가 고의 또는 과실로 인한 손해발생을 제외하고는 이에 대하여 책임을 부담하지 아니합니다.
제 19 조 (관할 법원)
서비스 이용으로 발생한 분쟁에 대해 소송이 제기되는 경우 민사 소송법상의 관할 법원에 제기합니다.
[부 칙]
1. (시행일) 이 약관은 2016년 9월 5일부터 적용되며, 종전 약관은 본 약관으로 대체되며, 개정된 약관의 적용일 이전 가입자도 개정된 약관의 적용을 받습니다.