• Restorative Dentistry and Endodontics
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• 제45권4호
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• pp.53.1-53.11
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• 2020

Objectives: This study investigated the incidence of root dentin defects after the use of different post space preparation (PSP) drills. Materials and Methods: Seventy-two bovine incisors were selected and obtained 14-mm-long root sections. Twelve roots served as controls with no intervention (G1). The 60 root canals remaining were instrumented using the crown-down technique with the ProTaper Next system and obturated using the lateral condensation technique. Specimens were randomly distributed into 5 groups (n = 12) according to the operative steps performed: G2, root canal instrumentation and filling (I+F); G3, I+F and PSP with Gates-Glidden drills; G4, I+FI+F and PSP with Largo-Peeso reamers; G5, I+F and PSP with Exacto drill; and G6, I+F and PSP with WhitePost drill. Roots were sectioned at 3, 6, 9, and 12 mm from the apex, and digital images were captured. The presence of root dentin defects was recorded. Data were analyzed by the χ² test, with p < 0.05 considered to indicate statistical significance. Results: Root dentin defects were observed in 39.6% of the root sections. No defects were observed in G1. G5 had significantly more cracks and craze lines than G1, G2, and G3 (p < 0.05), and more fractures than G1, G2, G3, and G4 (p < 0.05). When all root sections were analyzed together, significantly more defects were observed at the 12-mm level than at the 3-mm level (p < 0.05). Conclusions: PSP drills caused defects in the root dentin. Gates-Glidden drills caused fewer root defects than Largo-Peeso reamers and Exacto drills.

• 대한수학회논문집
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• 제30권3호
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• pp.313-325
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• 2015

An H-magic labeling in a H-decomposable graph G is a bijection $f:V(G){\cup}E(G){\rightarrow}\{1,2,{\cdots},p+q\}$ such that for every copy H in the decomposition, $\sum{_{{\upsilon}{\in}V(H)}}\;f(v)+\sum{_{e{\in}E(H)}}\;f(e)$ is constant. f is said to be H-V -super magic if f(V(G))={1,2,...,p}. In this paper, we prove that complete bipartite graphs $K_{n,n}$ are H-V -super magic decomposable where $$H{\sim_=}K_{1,n}$$ with $n{\geq}1$.

• 대한수학회보
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• 제52권1호
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• pp.105-123
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• 2015

Let $f_{\beta}=h_{\beta}+\bar{g}_{\beta}$ and $F_a=H_a+\bar{G}_a$ be harmonic mappings obtained by shearing of analytic mappings $h_{\beta}+g_{\beta}=1/(2isin{\beta})log\((1+ze^{i{\beta}})/(1+ze^{-i{\beta}})\)$, 0 < ${\beta}$ < ${\pi}$ and $H_a+G_a=z/(1-z)$, respectively. Kumar et al. [7] conjectured that if ${\omega}(z)=e^{i{\theta}}z^n({\theta}{\in}\mathbb{R},n{\in}\mathbb{N})$ and ${\omega}_a(z)=(a-z)/(1-az)$, $a{\in}(-1,1)$ are dilatations of $f_{\beta}$ and $F_a$, respectively, then $F_a\tilde{\ast}f_{\beta}{\in}S^0_H$ and is convex in the direction of the real axis, provided $a{\in}[(n-2)/(n+2),1)$. They claimed to have verified the result for n = 1, 2, 3 and 4 only. In the present paper, we settle the above conjecture, in the affirmative, for ${\beta}={\pi}/2$ and for all $n{\in}\mathbb{N}$.

• 대한수학회지
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• 제41권1호
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• pp.131-143
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• 2004

Let Ε and F be locally convex spaces over C. We assume that Ε is a nuclear space and F is a Banach space. Let f be a holomorphic mapping from Ε into F. Then we show that f is of uniformly bounded type if and only if, for an arbitrary locally convex space G containing Ε as a closed subspace, f can be extended to a holomorphic mapping from G into F.

• 대한수학회논문집
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• 제33권3호
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• pp.889-899
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• 2018

In this paper, we present some upper bounds for unitarily invariant norms inequalities. Among other inequalities, we show some upper bounds for the Hilbert-Schmidt norm. In particular, we prove $${\parallel}f(A)Xg(B){\pm}g(B)Xf(A){\parallel}_2{\leq}{\Large{\parallel}}{\frac{(I+{\mid}A{\mid})X(I+{\mid}B{\mid})+(I+{\mid}B{\mid})X(I+{\mid}A{\mid})}{^dA^dB}}{\Large{\parallel}}_2$$, where A, B, $X{\in}{\mathbb{M}}_n$ such that A, B are Hermitian with ${\sigma}(A){\cup}{\sigma}(B){\subset}{\mathbb{D}}$ and f, g are analytic on the complex unit disk ${\mathbb{D}}$, g(0) = f(0) = 1, Re(f) > 0 and Re(g) > 0.

• Archives of Pharmacal Research
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• 제21권6호
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• pp.640-644
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• 1998

AT cells exhibit defective cell cycle regulation following DNA damage. Previous studies have shown that induction of p53 and p2i proteins are delayed in response to ionizing rad iation, resulting in the failure of G1/S checkpoint in AT cells. In this study, further investigation of the molecular mechanisms underlying G1/S phase progression in AT cells was conducted. Exponentially growing normal and AT cells were exposed to 2 Gly of ionizing radiation and the expression levels and functional activities of Rb and E2F-1 proteins were determined. We observed overexpression of hyperphosphorylated Rb and E2F-1 proteins in AT cells, which was unaffected post-irradiation. Furthermore, gel shift assays showed that E2F-1-DNA binding was constitutive in AT cells, whereas it was inhibited in control cells following exposure to ionizing radiation. The data suggests that abnormalities in the function of Rb and E2F-1 proteins may also be responsible for the failure of AT cells to arrest in the G1/S checkpoint in response to DNA damage.

• Journal of Ginseng Research
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• 제40권2호
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• pp.121-126
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• 2016

Background: Ginsenoside F1, a pharmaceutical component of ginseng, is known to have antiaging, antioxidant, anticancer, and keratinocyte protective effects. However, the usage of ginsenoside F1 is restricted owing to the small amount found in Korean ginseng. Methods: To enhance the production of ginsenoside F1 as a 10 g unit with high specificity, yield, and purity, an enzymatic bioconversion method was developed to adopt the commercial enzyme Cellulase KN from Aspergillus niger with food grade, which has ginsenoside-transforming ability. The proposed optimum reaction conditions of Cellulase KN were pH 5.0 and $50^{\circ}C$. Results: Cellulase KN could effectively transform the ginsenosides Re and Rg1 into F1. A scaled-up biotransformation reaction was performed in a 10 L jar fermenter at pH 5.0 and $50^{\circ}C$ for 48 h with protopanaxatriol-type ginsenoside mixture (at a concentration of 10 mg/mL) from ginseng roots. Finally, 13.0 g of F1 was produced from 50 g of protopanaxatriol-type ginsenoside mixture with $91.5{\pm}1.1%$ chromatographic purity. Conclusion: The results suggest that this enzymatic method could be exploited usefully for the preparation of ginsenoside F1 to be used in cosmetic, functional food, and pharmaceutical industries.

• 한국패류학회지
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• 제26권4호
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• pp.291-296
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• 2010

본 연구에서는 제주도산 소라의 자원생태학적 특성치인 생잔율, 순간자연사망계수 및 순간어획사망계수, 어획개시연령을 추정하였으며, 직접 조사를 통한 자원량을 확인하였다. 생태학적 특성치 추정을 위한 표본은 2009년 9월부터 2010년 5월까지의 자료를 활용하였다. 순간전사망계수는 2.2062 /year로 추정되었으며, 순간자연사망계수는 0.8743/year로 추정되었다. 어구가입연령은 2.636 세로 추정되었다. 소라 자원을 가입당어획량 모델에 적용시킨 결과, 현재의 순간어획사망계수, 어획개시연령에서의 가입당생산량은 7.92 g으로 추정되었다. 따라서 현재의 순간어획사망계수를 그대로 유지한다면 어획개시연령을 2세에 맞추어야 하고, 현재의 어획개시연령을 유지한다면 순간어획사망계수를 0.2보다 낮은 수준으로 낮추어야 한다. $F_{0.1}$의 경우, 1세에서 2.58 g으로 가장 높은 가입당생산량을 나타내고 있다. 또한 가입당산란자원량 모델을 이용하여 생물학적 관리기준인 $F_{40%}$의 값을 현재의 어획상태를 고려하여 추정하였다. $F_{max}$, $F_{0.1}$, $F_{35%}$, 및 $F_{40%}$ 에서의 가입당생산량은 10.44 g, 1.87 g, 6.53 g and 7.46 g으로 추정되었다.

• 한국자연치유학회지
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• 제12권1호
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• pp.7-15
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• 2023

배경: 야생 망초(줄기와 잎)의 성분을 분석한 결과에서 생리활성 성분의 함유가 확인되어 화합물의 규명이 필요하다. 목적: 망초에는 항산화성 물질이 함유되었다는 선행연구 결과가 있어서 화합물의 분자적 구조를 연구하는 것이 목적이었다. 방법: 망초(줄기와 잎) 초음파 분쇄물을 1차로 90% 메탄올로, 다음에 유기 용매로 추출하였다. 다음에 HPLC, LC/MS 크로마토그래피 등으로 분획하였고, 분핵물을 NMR 분광기로 정밀 분석하여 분자의 구조를 동정하였다. 결과: 망초 100 g을 초음파기로 파쇄하여 90% methanol로 추출하고, 감압 농축하여 조 추출물 11.96 g을 얻었다. 조추출물을 유기용매로 재추출하여 n-hexane으로 123.8 mg, dichloromethane으로 448.2 mg, ethyl acetate(EA)로는 1047.7 mg, butanol로는 2563.8 mg, water로는 7.04 g을 얻었다. EA 추출물을 LC-MS 크로마토그래피로 분획하고, 정밀 분획하여 F1~F20의 20개를 얻었다. F15 분획을 다시 분획하여 9개를 얻었다. F17 분획을 재분획하여 10개의 분획을 얻었다. F15-7 분획물을 LC-MS 분석과 NMR 분광기로 분석한 결과는 이 화합물의 구조가 3,5-di-caffeoylquinic acid로 확인되었다. F17-4와 F17-5의 구조를 조사한 결과는 Quercetin-3-o-β-galactose로 동정 되었다. F17-10의 구조를 확인한 결과는 1,3,4-tri-caffeoylquinic acid로 확인되었다. 결론: 본 연구에서 망초 성분에도 항산화성 물질이 있었으며, 이의 활용성을 기대하며, 식물에는 항산화성 물질인 phenol 성분을 다양하게 함유하였다.

• Kyungpook Mathematical Journal
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• 제52권1호
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• pp.39-47
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• 2012

Let $\mathcal{F}$ be a family of meromorphic functions in a domain D, and let $k$, $n({\geq}2)$ be two positive integers, and let $S=\{a_1,a_2,{\ldots},a_n\}$, where $a_1$, $a_2$, ${\ldots}$, $a_n$ are distinct finite complex numbers. If for each $f{\in}\mathcal{F}$, all zeros of $f$ have multiplicity at least $k+1$, $f$ and $G(f)$ share the set $S$ in $D$, where $G(f)=P(f^{(k)})+H(f)$ is a differential polynomial of $f$, then$\mathcal{F}$ is normal in $D$.