• Korean Journal of Mathematics
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• 제27권3호
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• pp.735-741
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• 2019

Let ${\mathcal{H}}$ be a complex Hilbert space and ${\mathcal{B}}({\mathcal{H}})$ the algebra of all bounded linear operators on ${\mathcal{H}}$. In this paper, we prove that if ${\varphi}:{\mathcal{B}}({\mathcal{H}}){\rightarrow}{\mathcal{B}}({\mathcal{H}})$ is a unital surjective bounded linear map, which preserves m- isometries m = 1, 2 in both directions, then there are unitary operators $U,V{\in}{\mathcal{B}}({\mathcal{H}})$ such that ${\varphi}(T)=UTV$ or ${\varphi}(T)=UT^{tr}V$ for all $T{\in}{\mathcal{B}}({\mathcal{H}})$, where $T^{tr}$ is the transpose of T with respect to an arbitrary but fixed orthonormal basis of ${\mathcal{H}}$.

• BMB Reports
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• 제55권12호
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• pp.595-601
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• 2022

Polycomb Repressive Complex 2 (PRC2) exhibits key roles in mammalian development through its temporospatial repression of gene expression. EZH1 or EZH2 is the catalytic subunit of PRC2 that mediates the mono-, di- and tri-methylation of histone H3 lysine 27 (H3K27me1/2/3), H3K27me2/me3 being a hallmark of facultative heterochromatin. PRC2 is a chromatin-modifying enzyme that is recruited to a limited number of "nucleation sites", spreads H3K27 methylation and fosters chromatin compaction. EZH1 and EZH2 exhibit differences in their expression patterns, levels of histone methyltransferase activity (HMT) in the context of PRC2, and DNA/nucleosome binding activity. This suggests that their roles in heterochromatin formation are disparate. Dysregulation of PRC2 activity leads to aberrant gene expression and is implicated in cancer and developmental diseases. In this review, we discuss the distinct function of PRC2/EZH1 and PRC2/EZH2 in the early and late developmental stages. We then discuss the cancers associated with PRC2/EZH1 and PRC2/EZH2.

• Pediatric Gastroenterology, Hepatology & Nutrition
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• 제1권1호
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• pp.30-36
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• 1998

목 적: H. pylori가 만성유문부 위염의 원인으로 밝혀지면서 십이지장궤양 환자의 90%이상에서 그 위점막에 H. pylori의 존재가 확인되어 H. pylori의 박멸이 십이지장궤양 치료 및 재발에 미치는 영향에 대해 많은 연구가 이루어져 왔고 여러 보고에서 H. pylori의 박멸로 십이지장궤양의 재발율이 현저히 감소한다고 하였다. 소아에서는 성인에 비해 궤양의 빈도가 낮고 내시경적 검사의 제약으로 인하여 이에 대한 관심이 상대적으로 적었으며 소아 십이지장궤양에 대한 연구는 현재까지 거의 없는 실정이다. 이에 저자들은 내시경으로 진단한 소아 십이지장궤양에서 고식적 궤양치료와 H. pylori 병행치료후의 궤양의 재발에 대해 비교 분석해 보고자 하였다. 방 법: 1987년 7월부터 1995년 8월까지 서울대학병원 어린이 병원에 내원하여 내시경검사상 십이지장궤양으로 진단받은 105명(남:여=78:27)을 대상으로, 고식적 치료(ranitidine+antacid)를 행한 군과, H. pylori 진단을 받은 경우 고식적 치료와 함께 amoxicillin(50 mg/kg) 2주, denol(8 mg/kg) 4주의 균박멸 치료를 병행한 군으로 나누어 궤양재발율에 대하여 비교 조사하여 보았다. H. pylori 양성은 내시경생검을 통한 CLO test, Giemsa 염색과 혈청 IgG 항체검사중 둘 이상이 양성이거나 생검조직의 균배양이 양성인 것으로 하였다. 결 과: 1) 91년 5월이후 진단받은 38명(남:여=30:8) 중 원발성 십이지장궤양은 30명(78.9%)이었으며 모두 H. pylori 검사가 시행되어 이중 27명이 양성으로 H. pylori의 감염율은 90.0%였다. 2) H. pylori 양성인 27명 환아에 대해 고식적 치료와 H. pylori 치료를 병행하였는데 추적내시경검사상 23명에서 궤양치유와 함께 균의 박멸이 확인되어 H. pylori 치료성공율은 85.2%였다. 3) 6주의 치료후 추적검사상 박멸에 실패한 3명은 강화요법으로 균의 소실이 확인되었고 이중 1명(33.3%)이 치료종료 2.4년후 재발하였다. 4) 십이지장궤양 환아의 치료후 추적관찰 1년이내 궤양의 재발율은 고식적 치료만을 시행한 경우 65.3%였고 H. pylori 치료를 병행한 경우는 4.3%였다. 결 론: 십이지장궤양 환아들의 대부분이 H. pylori의 감염이 있으며 H. pylori 양성인 소아 십이지장궤양에서 H. pylori 박멸 요법은 궤양 재발의 방지를 위하여 반드시 필요하다.

• 대한핵의학회:학술대회논문집
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• 대한핵의학회 1999년도 제38차 추계학술대회
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• pp.27.2-27.2
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• 1999

• Korean Journal of Mathematics
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• 제27권2호
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• pp.357-374
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• 2019

In this paper, first we obtain some inequalities of Hadamard type for (h - m)-convex functions via Caputo k-fractional derivatives. Secondly, two integral identities including the (n + 1) and (n+ 2) order derivatives of a given function via Caputo k-fractional derivatives have been established. Using these identities estimations of Hadamard type integral inequalities for the Caputo k-fractional derivatives have been proved.

• 한국유기농업학회지
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• 제27권3호
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• pp.353-363
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• 2019

To identify four cyst nematodes (Heterodera schachtii, H. trifolii, H. glycines, H. sojae) that are economically important plant-parasitic nematodes in Korea, restriction fragment length polymorphism (RFLP) by 8 endonucleases (PstI, VspI, AlwI, RsaI, MvaI, EcoRI, Eco72I, Hinf I) was performed based on sequence difference of mitochondrial DNA cytochrome c oxidase subunit I (COI) gene. As a result, species-specific DNA band patterns by RsaI endonuclease were observed in H. schachtii. The specific patterns was in H. trifolii by 3 endonucleases (VspI, AlwI, Hinf I), and was in H. glycines by Hinf I. While, H. sojae was not digested by 4 endonuclease (VspI, AlwI, RsaI, Hinf I). This study showed that four cyst nematodes could be distinguished using RFLP by 4 endonucleases (RsaI, VspI, AlwI, Hinf I) based on the sequence difference of COI gene.

• The Korean Journal of Ecology
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• 제27권2호
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• pp.107-114
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• 2004

Tomato (Lycopersicon esculentum) seedlings exposed to various concentrations of $CdC1_2$ (0∼100 $\mu$M) in the nutrient solution for up to 9 days were analyzed with the seedling growth, $H_2O_2$ production, glutathione levels and activity changes of enzymes related to $H_2O_2$ removal. The growth of seedlings was inhibited with over 50 $\mu$M Cd, whereas the levels of $H_2O_2$ and glutathione were enhanced with Cd exposure level and time. Meanwhile, Cd exposure increased the activities of catalase (CAT) and glutathione reductase (GR) but decreased the activities of dehydroascorbate acid reductase (DHAR) and ascorbate peroxidase (APX) in both leaves and roots. These results suggest that the altered activities of antioxidant enzymes particularly involved in the $H_2O_2$ removal and the subsequent $H_2O$$_2$ accumulation could induce the Cd-induced phytotoxicity.

• 한국분말재료학회지
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• 제27권6호
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• pp.503-508
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• 2020

The mechanical properties and microstructures of hexagonal boron nitride (h-BN)-reinforced cement composites are experimentally studied for three and seven curing days. Various sizes (5, 10, and 18 ㎛) and concentrations (0.1%, 0.25%, 0.5%, and 1.0%) of h-BN are dispersed by the tip ultrasonication method in water and incorporated into the cement composite. The compressive strength of the h-BN reinforced cements increases by 40.9%, when 0.5 wt% of 18 ㎛-sized h-BN is added. However, the compressive strength decreases when the 1.0 wt% cement composite is added, owing to the aggregation of the h-BNs in the cement composite. The microstructural characterization of the h-BN-reinforced cement composite indicates that the h-BNs act as bridges connecting the cracks, resulting in improved mechanical properties for the reinforced cement composite.

• 한국수학교육학회지시리즈A:수학교육
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• 제14권1호
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• pp.27-27
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• 1975

• KSBB Journal
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• 제27권1호
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• pp.28-32
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• 2012

In this study, the treatment ability of the wastewater containing perchlorate by non-salt tolerant perchlorate reducing bacterial consortium (N-PRBC) was evaluated in a continuous stirred tank bioreactor (CSTR). To obtain the optimal operating condition the bioreactor was operated with the different wastewater empty bed retention time (EBRT). The treatment performance in the bioreactor could be maintained at 100 $mg-ClO_4{^-}L^{-1}$ up to a EBRT of 3 h, and the removal capacity in the CSTR was about 3.3 times higher than that in a batch operation. With a decrease from 9 h to 2 h in a EBRT, the volumetric perchlorate reduction rate was increased from 11.1 $mg-ClO_4{^-}L^{-1}h^{-1}$ to 50.0 $mg-ClO_4{^-}L^{-1}h^{-1}$, and the specific perchlorate reduction rates were increased from 3.01 $mg-ClO_4{^-}g-DCW^{-1}h^{-1}$. In conclusion, the treatment capacities in a CSTR were much better than those obtained in a batch operation.