• 디지털산업정보학회논문지
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• 제11권3호
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• pp.159-177
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• 2015

As smart phones become more common nowadays, mobile instant messengers such as kakao talk and line are used as essential communication tools exchanging information between individuals. Also, the mobile instant messengers extend their use to business area beyond communication between individuals. This study is on how factors of mobile instant messenger such as perceived security, perceived privacy, perceived enjoyment and perceived interactivity affect business continual usage intention through perceived usefulness. The proposed model is based on Expectation-Confirmation Theory of Oliver and Technology Acceptance Mode of Bhattacherjee. For an analysis, 159 survey responses were collected from the office workers in Seoul and nearby cities, having experiences of mobile instant messengers. To validate the proposed research model, PLS analysis is performed with the valid 154 questionnaires. The path analysis results are as follows. First, perceived security has a positive effect on expectation-confirmation. Second, perceived enjoyment has a positive effect on perceived usefulness. Third, perceived interactivity has a positive effect on both perceived usefulness and expectation-confirmation. Fourth, perceived usefulness has a positive usefulness on satisfaction and continual usage intention of mobile instant messenger. Last, expectation-confirmation has a positive effect on perceived usefulness, and satisfaction has a positive effect on continual usage intention of mobile instant messenger. Since the mobile instant messenger may bring a pressure of work and a violation of privacy, it is necessary that the company provide a guideline for use of the mobile instant messenger and establish the in-house mobile instant messenger system.

• Archives of Pharmacal Research
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• 제21권2호
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• pp.120-127
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• 1998

Peroxisome proliferators induce hepatic peroxisome proliferation and hepatic tumors in rodents. These chemicals increase the expression of the peroxisomal $\beta$-oxidation pathway and the cytochrome P-450 4A family, which metabolizes lipids, including eicosanoids. Peroxisome proliferators transiently induce increased cell proliferation in vivo. However, peroxisome proliferators are weakly mitogenic and are not co-mitogenic with epidermal growth factor (EGF) in cultured hepatocytes. Earlier study found that the peroxisome proliferator ciprofibrate is cornitogenic with eicosanoids. In order to study possible mechanisms of the comitogenicity of peroxisome proliferator ciprofibrate and eicosanoids' we hypothesized that the co-mitogenicity may result from synergistic or additive increases of second messengers in mitogenic signal pathways. We therefore examined the effect of the peroxisome proliferator ciprofibrate, prostaglandin $F_2_{\alpha}$($PGF_2{\alpha}$) and the combination of ciprofibrate and $PGF_2{\alpha}$ with or without growth factors on the protein kinase C (PKC) activity, and inositol-1, 4, 5-triphosphate ($IP_{3-}$) and intracellular calcium ($[Ca^{2+}]_i$) concentrations in cultured rat hepatocytes. The combination of ciprofibrate and $PGF_2{\alpha}$ significantly increased particulate PKC activity. The combination of ciprofibrate and $PGF_2{\alpha}$ also significantly increased EGF, transforming growth factor-$\alpha$ ($TGF_2{\alpha}$) and hepatic growth factor (HGF)-induced particulate PKC activity. The combination of ciprofibrate and $PGF_2_\alpha$greatly increased $[Ca^{2+}]_i$. However, the increases of PKC activity and $[Ca^{2+}]_i$ by ciprofibrate and $PGF_2{\alpha}$ alone were much smaller. Neither ciprofibrate or $PGF_2{\alpha}$ alone nor the combination of ciprofibrate and $PGF_2{\alpha}$ significantly increased the formation of $IP_3$. The combination of ciprofibrate and $PGF_2{\alpha}$, however, blocked the inhibitory effect of $TGF-{\beta}$ on particulate PKC activity and formation of $IP_3$ induced by EGF. These results show that co-mitogenicity of the peroxisome proliferator ciprofibrate and eicosanoids may result from the increase in particulate PKC activity and intracellular calcium concentration but not from the formation of $IP_3$.

• International Journal of Oral Biology
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• 제36권2호
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• pp.83-89
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• 2011

Substantia gelatinosa (SG) neurons receive synaptic inputs from primary afferent $A{\delta}$- and C-fibers, where nociceptive information is integrated and modulated by numerous neurotransmitters or neuromodulators. A number of studies were dedicated to the molecular mechanism underlying the modulation of excitability or synaptic plasticity in SG neurons and revealed that second messengers, such as cAMP and cGMP, play an important role. Recently, cAMP and cGMP were shown to downregulate each other in heart muscle cells. However, involvement of the crosstalk between cAMP and cGMP in neurons is yet to be addressed. Therefore, we investigated whether interaction between cAMP and cGMP modulates synaptic plasticity in SG neurons using slice patchclamp recording from rats. Synaptic activity was measured by excitatory post-synaptic currents (EPSCs) elicited by stimulation onto dorsal root entry zone. Application of 1 mM of 8-bromoadenosine 3,5-cyclic monophosphate (8-Br-cAMP) or 8-bromoguanosine 3,5-cyclic monophosphate (8-Br-cGMP) for 15 minutes increased EPSCs, which were maintained for 30 minutes. However, simultaneous application of 8-BrcAMP and 8-Br-cGMP failed to increase EPSCs, which suggested antagonistic cross-talk between two second messengers. Application of 3-isobutyl-1-methylxanthine (IBMX) that prevents degradation of cAMP and cGMP by blocking phosphodiesterase (PDE) increased EPSCs. Co-application of cAMP/cGMP along with IBMX induced additional increase in EPSCs. These results suggest that second messengers, cAMP and cGMP, might contribute to development of chronic pain through the mutual regulation of the signal transduction.

• 융합보안논문지
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• 제23권3호
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• pp.13-20
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• 2023

본 연구는 안드로이드 환경에서 널리 사용되는 두 개의 보안 메신저인 Signal과 Telegram에 대한 디지털 포렌식 분석을 진행하였다. 현재 모바일 메신저가 일상생활의 중요한 역할을 하는 만큼, 이들 앱 내부의 데이터 관리와 보안성은 매우 중요한 이슈가 됐다. Signal과 Telegram은 그중에서도 사용자들 사이에서 높은 신뢰성을 받고 있는 보안 메신저로, 암호화 기술을 바탕으로 사용자들의 개인 정보를 안전하게 보호한다. 하지만 이러한 암호화된 데이터를 어떻게 분석할 수 있을지에 대해서는 아직까지 많은 연구가 필요하다. 본 연구에서는 이러한 문제점을 해결하기 위해 Signal과 Telegram의 메시지 암호화와 안드로이드 디바이스 내 데이터베이스 구조 및 암호화 방식에 대하여 깊이 있는 분석을 진행하였다. Signal의 경우, 복잡한 알고리즘으로 인해 외부에서 접근하기 어려운 암호화된 메시지를 성공적으로 복호화 하여 내용을 확인할 수 있었다. 또한 두 메신저 앱의 데이터베이스 구조를 세밀하게 분석하여 해당 정보를 수시로 활용할 수 있는 폴더 구조 및 파일 형태로 정리하는 작업도 진행했다. 이렇게 분석한 정보를 바탕으로 보다 발전된 기술과 방법론을 적용함으로써, 앞으로 더욱 정확하고 세밀한 디지털 포렌식 분석이 가능할 것으로 기대된다. 이 연구가 Signal과 Telegram 같은 보안 메신저에 대한 이해를 높이는 데 도움을 주며, 이로 인해 개인 정보 보호와 범죄 예방 등 여러 측면에서의 활용 가능성이 열릴 것으로 예상된다.

• 천문학회지
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• 제37권5호
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• pp.413-420
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• 2004

The current state and future prospects of ultra high energy cosmic ray physics are reviewed. These cosmic rays with energies well above $10^{18}$ eV are messengers of an unknown extremely high-energy universe.

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 1998년도 학술발표회
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• pp.17-17
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• 1998

Although the activation mechanism of PLC-${\gamma}$ isozyme by protein tyrosine kinase (PTK) is well established, several lines of evidence indicate that PLC-${\gamma}$ isozymes can be activated directly by several lipid-derived second messengers In the absence of tyrosine phosphorylation.(omitted)

• 한국생물물리학회:학술대회논문집
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• 한국생물물리학회 2002년도 제9회 학술 발표회 프로그램과 논문초록
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• pp.15-15
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• 2002

Cyclic nucleotide phosphodiesterases (PDEs) regulate physiological processes by degrading ubiquitous intracellular second messengers, cAMP or cGMP. The first crystal structure of PDE4D catalytic domain and a bound inhibitor, zardaverine, was determined. Zardaverine binds to a highly conserved pocket that includes the catalytic metal binding site.(omitted)

• Journal of Microbiology
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• 제35권2호
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• pp.152-157
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• 1997

Infection of human fibroblast (HF) cells with human cytomegalovirus (HCMV) result in changes in the intracellular level of second messengers. Since nitric oxide (NO) production has been known to be related with other second messengers, it is probable that HCMV infection of HF cells may involve NO. To test this possibility, the amount of NO was measured following ogenous addition of NO generators such as sodium nitroprusside (SNP) or S-nitroso-N-a-cetylpenicillamine (SNAP) immediately after HCMV infection, however, inhibited virus multiplication. Furthermore, immunoblot experiment using monoclonal antibody to HCMV major immediate early (MIE) proteins or CAT assay using pCMVIE/CAT (plasmid containing CAT gene driven by HCMV MIE promoter) revealed that SNP or SNAP blocked the MIE gene expression. SNP was more effective than SNAP in hibiting HCMV multiplication or MIE gene expression. SNP produced more NO than SNAP in inhibiting HCMV multiplication or MIE gene expression. SNP produced more NO than SNAP. Although the mechanism for the inhibition of HCMV multiplication and MIE gene expression by NO is still elusive some correlation with NO-mediated inhibition of HCMV-induced increase in cytosolic free Ca$\^$2+/ concentration ([Ca$\^$2+/]) was observed. The increase of [Ca$\^$2+/] following HCMV infection was inhibited by SNP, and less effectively by SNAP. Raising [Ca$\^$2+/ with bromo-A23187 partially reversed the SNP block of MIE gene expression. Thus, there appear to e some relationships among NO. [Ca$\^$2+/], and HCMV MIE gene expression.

• 디지털콘텐츠학회 논문지
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• 제13권3호
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• pp.401-412
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• 2012

스마트폰을 통한 사용자간 소통방법은 휴대성과 공간의 제약을 넘어선 새로운 모바일 커뮤니케이션의 패러다임을 만들고 있다. 스마트폰 모바일 인스턴트 메신저(Mobile Instant Messenger: MIM)는 기존의 데스크톱 환경에서 시작하여, 멀티미디어 콘텐츠, 텍스트, 음성 등 다양한 소통 기능을 제공하고 있다. 유치원, 어린이집에서는 학부모와 소통을 위해 홈페이지, 전화, SMS, 프린트된 유인물, 수기작성 알림장 등을 활용하고 있다. 아이즈플러스는 학부모와 교사, 원장과 사진, 동영상, 채팅 및 등/하원 관리를 포함한 스마트폰을 이용한 커뮤니케이션 활성화를 목적으로 개발되었으며 영유아교육기관 전용 모바일 메신저 초기 개발 사례라는데 그 의의가 있다. 본 연구는, 사용자 환경과 커뮤니케이션 유형분석, App의 기획과정과 스토리텔링을 활용한 인터페이스 디자인개발과 사례를 연구함으로써, 특정그룹을 대상으로 하는 모바일 메신저 개발의 접근법을 제시하였다.

• 정보보호학회논문지
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• 제31권1호
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• pp.61-71
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• 2021

인스턴트 메신저는 현대인의 의사소통 수단으로 스마트폰과 PC 등에서 이용 가능하며, 개별로 사용하거나 연동해서 사용할 수 있다. 메시지, 통화 및 파일 공유 등의 다양한 기능을 제공하는 메신저는 사용자의 행위정보를 포함하므로 포렌식 수사관점에서 중요한 증거로서의 가치를 지닌다. 하지만 스마트폰 데이터는 데이터 추출의 어려움이나 제작자의 보안기술 적용으로 분석의 어려움이 있다. 그러나 스마트폰과 PC 메신저를 연동해 사용하고 있는 경우 스마트폰 대신 PC에서 대화 내용 및 사용자 데이터 획득이 가능하다. 본 논문에서는 Windows 10 환경에서 Wire 메신저의 크리덴셜 정보를 획득했으며, 다른 PC에서 인증 과정 없이 로그인 가능함을 보였다. 또한, 사용자 행위를 기반으로 생성되는 주요 아티팩트 선별하고 정리하였다.