Backgraound : There have been many reports on the pathogenesis of sepsis-induced acute respiratory distress syndrome(ARDS) but, the precise mechanism has not been elucidated. This study examined the protective effect of an inhibition of platelet activating factor(PAF) remodeling and the adhesion molecule on the oxidative stress of the lungs in rats with an endotoxin induced acute lung injury(ALI). Methods : ALI was induced in Sprague-Dawley rats by instilling an E-coli endotoxin into the trachea. Ketotifen and fucoidan were used respectively to inhibit PAF remodeling and adhesion molecule. The lung leak index, lung myeloperoxidase(MPO) activity, bronchoalveolar lavage(BAL) fluid neutrophil count and lyso PAF acetyltransferase activity(AT), were measured and an ultrastructural study and cytochemical electron microscopy were performed. Results : The lung leak index, lung MPO activity, BAL fluid neutrophil count and lyso PAF AT activity was higher in the endotoxin-treated rats. In addition, severe destruction of the pulmonary architecture and increased hydrogen peroxide production were identified. These changes were reversed by ketotifen. However, fucoidan did not appear to have any protective effects. Conclusion : The inhibition of PAF remodeling appeared to be effective in decreasing the endotoxin-induced ALI. In addition, this effect might be derived from the inhibition of neutrophilic oxidative stress. However, the inhibition of the adhesion molecules by fucoidan appeared to be ineffective in decreasing the endotoxin-induced ALI.
Kim, Hee Yeon;Kim, Hye Jin;Hwang, Ji Sun;Lee, Won Jun
Journal of Life Science
/
v.24
no.11
/
pp.1180-1186
/
2014
Autophagy, the lysosomal degradation pathway, is an intracellular recycling system that is necessary for the metabolic benefits of exercise and for producing lasting beneficial effects of exercise in various diseases. However, the most recent studies have only examined the effect of a single bout of exercise or resistance exercise on autophagic responses. To determine the differential effects of acute and chronic exercise on the expression of autophagy-related genes in D. melanogaster, white-eyed mutant D. melanogaster were assigned randomly to four groups: control, acute exercise, 2 hr chronic exercise, and 3 hr chronic exercise. The flies were exercised using a mechanized platform known as the Power Tower. Our results revealed that a single bout of exercise resulted in increased mRNA levels of the Atg8a gene (~20%, p<0.05). However, Atg1 and Atg6 mRNA expression were not induced by acute exercise. Transcript levels of Atg6 (~29%, p<0.05) related to the nucleation of autophagosomes were significantly induced by 2 hr of chronic exercise. However, this chronic exercise was not enough to increase Atg1 and Atg8a mRNA expression. On the other hand, 3 hr of exercise for 7 days significantly increased Atg1, Atg6, and Atg8a gene expression-about 57%, 37%, and 71%, respectively (p<0.05). These results suggest that a single bout of exercise is not enough to induce full activation of selected autophagy-related genes in D. melanogaster. Our results demonstrated that chronic regular exercise induced autophagy-related gene expression, suggesting that chronic regular exercise training might be required to activate autophagic responses important for producing beneficial effects of exercise in various diseases.
The sexual reproduction of the unicellular green alga Chlamydomonas is reviewed for a comprehensive understanding of the complex processes. The sexual life cycle of C. reinhardtii is distinguished into five main stages: gametogenesis, gamete activation, cell fusion, zygote maturation, and meiosis and germination. Gametogenesis is induced by nitrogen starvation in the environment. C. reinhardtii has two mating types: mating type plus ($mt^+$) and mating type minus ($mt^-$), controlled by a single complex mating type locus ($MT^+$ or $MT^-$) on linkage group VI. In the early gametogenesis agglutinins are synthesized. The $mt^+$ and $mt^-$ agglutinins are encoded by the autosomal genes SAG1 (Sexual AGglutination1) and SAD1 (Sexual ADhesion1), respectively. The agglutinins are responsible for the flagellar adhesion of the two mating type of gametes. The flagellar adhesion initiates a cAMP mediated signal transduction pathways and activates the flagellar tips. In response to the cAMP signal, mating structures between two flagella are activated. The $mt^+$ and $mt^-$ gamete-specific fusion proteins, Fus1 and Hap2/Gcs1, are present on the plasma membrane of the two mating structures. Contact of the two mating structures leads to develop a fertilization tubule forming a cytoplasmic bridge between the two gametes. Upon fusion of nuclei and chloroplasts of $mt^+$ and $mt^-$ cells, the zygotes become zygospores. It is notable that the young zygote shows uniparental inheritance of chloroplast DNA from the $mt^+$ parent and mitochondrial DNA from the $mt^-$ parent. Under the favorable conditions, the zygospores divide meiotically and germinate and then new haploid progenies, vegetative cells, are released.
This experiment was carried out to confirm that phytochrome regulates anthocyanin bio-synthesis during cell suspension culture system of grape or not. In suspension culture of grape, maximum accumulation of anthocyanin was observed at the stationary phase under continuous white light condition. From mono-chromatic light interruption for 24h at the 4th or 7th day on the suspension cultured cells, the anthocyanin accumulation was highly enhanced at the light interruption at 7th day than 4th day under all monochromatic light treatment. However, the cell growth patterns were not affected by any light treatment. In the darkness, the anthocyanin synthesis was very low but remarkably increased by blue light or red light irradiation. However, the increase of anthocyanin accumulation by blue or red light was suppressed by far-red light in the suspension cells of grape. This suppression by far-red light on the anthocyanin synthesis also observed on the cells treated red or far-red light alternatively. These results implied that phytochrome regulation system may be involved in the anthocyanin biosynthesis of the suspension grape cells. By RNA expression analysis, chalcone synthase (CHS) gene was expressed highly by blue and red light but low by far-red light. The synergistic increase of CHS gene expression was also observed at the treatment of blue light followed by red for 24h. This result may explain the increase of anthocyanin accumulation in B/R treatment. Although the expression of phytochrome gene (PHYA or PHYB) was not highly increased by all light treatment (blue, red, and far-red light) the expression of both PHYA gene and PHYB gene was increased a little in cells treated red or far-red light. In grape suspension cells, the red light enhanced the anthocyanin synthesis, whereas the far-red light was suppressed. Although it was not confirmed whether or not phytochrome gene is activated in anthocyanin accumulating grape cells, we believed that anthocyanin biosynthesis in grape cells may be regulated under phytochrome signal transduction system.
Vinclozolin (VCZ) is a systemic fungicide commonly used in fruits, vegetables and the wine industry. VCZ and its metabolites, butenoic acid (M1) and enanilide (M2) derivatives, act as anti-androgens through actions on the androgen receptor. Although there is growing body of evidence that VCZ's action as an endocrine disrupting chemical (EDC) in male reproductive physiology and pathphysiology, no evidence on the VCZ's EDC action in female is available yet. Previously we found that the prepubertal VCZ exposures could effectively delay the onset of puberty in female rats, suggesting the postponed or weakened activities of hypothalamus-pituitary-ovary (H-P-O) reproductive hormonal axis. The present study was performed to examine whether the VCZ administration affects the transcriptional activities of reproductive hormone-related genes in the same animal model. VCZ (10 mg/kg/day) was administered daily from postnatal day 21 (PND 21) through the day when the first vaginal opening (V.O.) was observed. To determine the transcriptional changes of reproductive hormone-related genes in hypothalamus and pituitary, total RNAs were extracted and applied to the semiquantitative reverse transcription polymerase chain reaction (RT-PCR). As a result, treatment with VCZ significantly lowered the transcriptional activity of nitric oxide synthase-2 (NOS-2) which is known to adjust gonadotropin-releasing hormone (GnRH) secretion in the hypothalamus (p<0.01). Similarly, the mRNA levels of KiSS-1, G protein-coupled receptor 54 (GPR54) and GnRH were significantly decreased in hypothalamus (p<0.01) from VCZ-treated group. As expected, the transcriptional activities of luteinizing hormone-${\beta}$ (LH-${\beta}$) and follicle stimulating hormone-${\beta}$ (FSH-${\beta}$) in the anterior pituitary from VCZ-treated group were also significantly lower than those from the control group. The present study indicates that(i) the inhibitory effect of VCZ exposure on the onset of puberty in immature female rats could be derived from the reduced transcriptional activities of gonadotropin subunits and their upstream modulators such as GnRH and KiSS-1 in hypothalamus-pituitary neuroendocrine axis, and (ii) these inhibitory effects could be mediated by NO signaling pathway.
This study aimed to investigate the anti-inflammatory effect of the ethanol extract from Chondrus ocellatus Holmes (COHEE) in RAW 264.7 cells and in a mouse ear edema model, by measuring the production of lipopolysaccharide-induced inflammatory response mediators. There were no cytotoxic effects on the proliferation of macrophages treated with COHEE compared with the control. COHEE inhibited the production of nitric oxide and pro-inflammatory cytokines [interleukin (IL)-6, tumor necrosis factor-α, and IL-1β]. The extract also reduced the expression of inducible nitric oxide synthase, cyclooxygenase-2, nuclear factor-κB p65, and phosphorylated mitogen-activated protein kinase in a dose-dependent manner. In the croton-oil-induced ear edema model, COHEE decreased the formation of mouse ear edema at the highest dose compared with the control, and histological analysis revealed that the epidermal/dermal tissue thickness and mast cell numbers were reduced. Therefore, these results suggest that COHEE may be a promising topical anti-inflammatory therapeutic material through its action of modulating NF-κB and the MAPK signaling pathway.
Seo, Jeong Il;Yoo, Si Uk;Gong, Sung Hyeon;Hwang, Gwang Su;Lee, Hyeon Jung;Kim, Joong Pyo;Choi, Hyeon;Lee, Bo Young;Mok, Ji Sun
Clinical and Experimental Pediatrics
/
v.48
no.7
/
pp.706-710
/
2005
Purpose : Early diagnosis of congenital hearing loss through the neonatal hearing screening test minimizes language defect. This research intends to identify frequency of congenital hearing loss in infants through neonatal hearing screening test with the aim of communicating the importance of hearing test for infants. Methods : From May 20, 2003 to May 19, 2004, infants were subjected to Automated Auditory Brainstem Response test during one month of birth to conduct the test with 35 dB sound. Infants who passed the 1st round of hearing test, were classified into 'pass' group whereas those who did not were classified into 'refer' group. Infants who did not 'pass' in the hearing test conducted within one month of birth were subjected to re-test one month later, and if classified as 'refer' during the re-test, they were subjected to the diagnosis for validation of hearing loss by requesting test to the hearing loss clinic. Results : There was no difference among the 'pass' and 'refer' group in terms of form of childbirth, weight at birth and gestational age. In the 1st test, total of 45 infants were classified into 'refer' group. Six among 35 who were subjected to re-test(17%) did not pass the re-test, and all were diagnosed with congenital hearing loss. This corresponds to 0.35%(3.5 per 1,000) among total number of 1,718 subjects. Conclusion : In our study the congenital hearing loss tends to be considerably more frequently than congenital metabolic disorder. Accordingly, newly born infants are strongly recommended to undergo neonatal hearing screening test.
Kim, Sun Young;Lee, You Jin;Park, Eun Hye;Yi, Ho Keun;Jo, Dae Sun;Kim, Jung Soo;Hwang, Pyoung Han
Clinical and Experimental Pediatrics
/
v.51
no.3
/
pp.307-314
/
2008
Purpose : Capsaicin, the major pungent ingredient in red pepper, has long been used in spices and food additives. It has been recently shown to induce apoptosis in several cell lines through a not well known mechanism. The aim of this study was to investigate the apoptosis-inducing effect of capsaicin on gastric cancer cells, and to provide valuable information concerning the application of capsaicin for therapeutic purposes. Methods : Cultured SNU-668 cells were treated with capsaicin. We analyzed cell survival by trypan blue and crystal violet analysis, cell cytotoxicity by MTT assay, apoptosis by nuclear condensation and DNA fragmentation, bcl-2 and bax mRNA expression by RT-PCR, and the expression of apoptosis related proteins by Western immunoblot analysis. In order to assess whether the growth inhibitory effect of anticancer drugs is enhanced by capsaicin, we investigated the effects of cell cytotoxicity and the expression of apoptosis related proteins of etoposide and adriamycin treated with capsaicin in cells. Results : Capsaicin inhibited growth of SNU-668 cells in a dose-dependent manner. This inhibitory effect of capsaicin on cell growth was mainly due to the induction of apoptosis as evidenced by DNA fragmentation, nuclear condensation and the expression of apoptosis related proteins. Furthermore, capsaicin prominently reduced the ratio of anti-apoptotic Bcl-2 to pro-apoptotic Bax and consequently increased caspase-3 activity. The cells treated with capsaicin were more sensitive to death induced by etoposide and adriamycin than the cells without capsaicin. Conclusion : These results demonstrate that capsaicin efficiently induced apoptosis in SNU-668 cells through a caspase-3-dependent mechanism and sensitizes cancer cells to anticancer drugs toward apoptotic cell death, which may contribute to its anticancer effect and chemosensitizer function against gastric cancer.
The prognosis of chronic hepatitis C is very variable. In some, the disease is progressive and cirrhosis can develop from chronic hepatitis C. Hepatitis C virus(HCV) may act as a trigger towards hepatocellular carcinoma in patients with cirrhosis. Interferon has been used for the treatment of chronic hepatitis C in abroad, 16 patients with chronic C liver disease were treated with ${\alpha}$-interferon (alfa-2b; "Intron A" Schering Corp. Kenilworth. NJ). All patients were given ${\alpha}$-interferon in subcutaneous doses of 3 million units three times weekly for 1 to 9 months. During therapy, CBC and ALT levels were checked weakly to monthly. After therapy, patients were followed for 1 to 8 months. Among 16 patients treated with ${\alpha}$-interferon, progressive decrease of ALT levels was observed in 14(87.5%). In 11 patients(68.8%), ALT levels fell into the normal range during therapy, and in 9 of 11, within one month after therapy, 6 months after the completion of therapy in 4 of 9 patients(44.4%) whose ALT levels were in the normal range, ${\alpha}$-interferon seems to have effect in controlling disease activity in patients with chronic hepatitis C. But the changes in the usage of ${\alpha}$-interferon, dose and duration, long term follow up and more convenient and simple tests for HCV detection are recommended for the better effect and the exact evaluation on the effect of ${\alpha}$-interferon therapy in patients with chronic hepatitis C.
The severe damage of cultural heritages induced by natural hazards like heavy rain has been dramatically increased since 1990. The number of the repair works of stone heritage of 2005 was six times as many as those of 1986 year. Especially the ratio of the repair works of Gyeongsang Province and Jeolla Province stood 63% of those of all over the country. Since 1990, the typhoons usually struck the southern part of Korea and went northward. The heavy damage of stone heritages in two provinces was caused by them. We made a preliminary survey the stone heritages that exposed to the natural hazards on the basis of repair works of them and a field survey. The analysis results indicate that the natural hazards such as landslide and soil disaster of the stone heritages related to a sloping surface stood 58% of all kind of natural hazards. The reasons are caused by the 59 % of all the stone heritages distributed in a sloping surface resulted in natural hazards like landslide and soil disaster. The bases of stone heritages can be easily eroded by the surface water with high energy induced by heavy rainfall. Most of the stone heritages like Maebul were engraved on a natural rock wall(outcrop). But some of them engraved on rolling stones are very vulnerable in a change of a base condition caused by erosion and ground subsidence and they can be tilted or fell down. The distribution of the stone heritages vulnerable in natural hazard is related to that of the rainfall distribution compounded five typhoons after 1990. Most of them are included in level two on the rainfall distribution map except those of Taean peninsula and some of Gyeonggi Province. They seem to be rather related to the rainfall distribution of the Typhoon Olga.
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.