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췌장암에서 Cyclooxygenase - 2 발현의 역할
김은경,이용욱,이규택,최규완,박동일,백승운,이준행,이종균,고광철,이풍렬,이종철,김재준,김완선,공구 대한소화기학회 2001 대한소화기학회지 Vol.38 No.3
Background/Aims: Accumulating evidence suggests that the use of NSAID may reduce the incidence of colorectal cancer. The likely mechanisms of these effects by NSAID is cyclooxygenase-2 (COX-2)-related inhibition of tumor proliferation and induction of apoptosis. The aim of our study was to examine possible roles and clinical significance of COX-2 expression in pancreatic cancer. Methods: Seventy-two pancreatic adenocarcinoma tissue specimens were obtained from surgical resection. After the immunohistochemical staining of the specimens, we examined proliferation activity (assayed by Ki-67 expression), apoptosis (by TUNEL stain), and microvessel density (by CD34 expression). We also investigated the relationship between the immunohistochemical expression of COX-2 and various clinicopathological characteristics. Results: The COX-2 positive rate in pancreatic epithelial cells was 41.7%. Proliferation index (PI) was significant higher in COX-2 positive specimens comparing to negative specimen (p=0.015) and the increase in intensity of COX-2 expression correlated with increasing PI (p=0.036). Apoptotic index (AI) was significantly higher in positivee COX-2 expression than in negative expression (p=0.044), but there was no significant difference in AI/PI between the COX-2 positive and negative specimens (p=0.44). The expression of COX-2 protein did not correlate with microvessel density, sex, age, differentiation, tumor size, stage, metastasis or patients survival. Conclusions: The expression of COX-2 enzyme in pancreatic cancer contributes to tumor proliferation, but is not related to apoptosis, angiogenesis or clinical characteristics. Further study is needed to examine the clinical usefulness of NSAID and COX-2 selective inhibitors.
Yves Guéron(Yves Guéron ) 서울대학교 경제연구소 2023 經濟論集 Vol.62 No.1
This paper offers a survey of the recent literature related to the economics of data. In particular, we look at how data can confer market power and facilitate collusion, and consider some of the privacy implications of data ownership.
Redox-Dependent Spatially Resolved Electrochemistry at Graphene and Graphite Step Edges
Gü,ell, Aleix G.,Cuharuc, Anatolii S.,Kim, Yang-Rae,Zhang, Guohui,Tan, Sze-yin,Ebejer, Neil,Unwin, Patrick R. American Chemical Society 2015 ACS NANO Vol.9 No.4
<P>The electrochemical (EC) behavior of mechanically exfoliated graphene and highly oriented pyrolytic graphite (HOPG) is studied at high spatial resolution in aqueous solutions using Ru(NH<SUB>3</SUB>)<SUB>6</SUB><SUP>3+/2+</SUP> as a redox probe whose standard potential sits close to the intrinsic Fermi level of graphene and graphite. When scanning electrochemical cell microscopy (SECCM) data are coupled with that from complementary techniques (AFM, micro-Raman) applied to the same sample area, different time-dependent EC activity between the basal planes and step edges is revealed. In contrast, other redox couples (ferrocene derivatives) whose potential is further removed from the intrinsic Fermi level of graphene and graphite show uniform and high activity (close to diffusion-control). Macroscopic voltammetric measurements in different environments reveal that the time-dependent behavior after HOPG cleavage, peculiar to Ru(NH<SUB>3</SUB>)<SUB>6</SUB><SUP>3+/2+</SUP>, is not associated particularly with any surface contaminants but is reasonably attributed to the spontaneous delamination of the HOPG with time to create partially coupled graphene layers, further supported by conductive AFM measurements. This process has a major impact on the density of states of graphene and graphite edges, particularly at the intrinsic Fermi level to which Ru(NH<SUB>3</SUB>)<SUB>6</SUB><SUP>3+/2+</SUP> is most sensitive. Through the use of an improved voltammetric mode of SECCM, we produce movies of potential-resolved and spatially resolved HOPG activity, revealing how enhanced activity at step edges is a subtle effect for Ru(NH<SUB>3</SUB>)<SUB>6</SUB><SUP>3+/2+</SUP>. These latter studies allow us to propose a microscopic model to interpret the EC response of graphene (basal plane and edges) and aged HOPG considering the nontrivial electronic band structure.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2015/ancac3.2015.9.issue-4/acsnano.5b00550/production/images/medium/nn-2015-00550c_0009.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn5b00550'>ACS Electronic Supporting Info</A></P>
Layer-by-Layer Doping of Few-Layer Graphene Film
Gü,neş,, Fethullah,Shin, Hyeon-Jin,Biswas, Chandan,Han, Gang Hee,Kim, Eun Sung,Chae, Seung Jin,Choi, Jae-Young,Lee, Young Hee American Chemical Society 2010 ACS NANO Vol.4 No.8
<P>We propose a new method of layer-by-layer (LbL) doping of thin graphene films. Large area monolayer graphene was synthesized on Cu foil by using the chemical vapor deposition method. Each layer was transferred on a polyethylene terephthalate substrate followed by a salt-solution casting, where the whole process was repeated several times to get LbL-doped thin layers. With this method, sheet resistance was significantly decreased up to ∼80% with little sacrifice in transmittance. Unlike samples fabricated by topmost layer doping, our sample shows better environmental stability due to the presence of dominant neutral Au atoms on the surface which was confirmed by angle-resolved X-ray photoelectron spectroscopy. The sheet resistance of the LbL-doped four-layer graphene (11 × 11 cm<SUP>2</SUP>) was 54 Ω/sq at 85% transmittance, which meets the technical target for industrial applications.</P><P><B>Graphic Abstract</B> <IMG SRC='http://pubs.acs.org/appl/literatum/publisher/achs/journals/content/ancac3/2010/ancac3.2010.4.issue-8/nn1008808/production/images/medium/nn-2010-008808_0006.gif'></P><P><A href='http://pubs.acs.org/doi/suppl/10.1021/nn1008808'>ACS Electronic Supporting Info</A></P>
Effect of Welding Time on Resistance Spot Weldability of Aluminum 5052 Alloy
Gu‑Cheol Kim,Insung Hwang,Munjin Kang,Dongcheol Kim,Hyunsung Park,김영민 대한금속·재료학회 2019 METALS AND MATERIALS International Vol.25 No.1
In the study, the effect of welding time on resistance spot weldability of aluminum 5052-H32 alloy was analyzed throughsimulation and experiments. The resistance spot weldability was evaluated by measuring the tensile shear strength, nuggetsize, and hardness of welds with variations in the welding time. The simulated results of parameters such as tensile shearstrength and nugget size obtained using the SORPAS program were compared with the experimental results. Furthermore,a simulation was performed to calculate the temperature inside the weld nugget based on the distance from the center of thenugget. Hence, an optimum welding time to retain the required weld strength of the aluminum 5052-H32 alloy was obtained.