• Title/Summary/Keyword: Without TTP

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Enviromental Toxic Agents on Genetic Material and Cellular Activity III. DNA Polymerase Inhibitors on Repair of Mutagen-Induced DNA Damage in Mammalian Cells (환경성 유해요인이 유전물질과 세포활성에 미치는 영향 III. 포유동물세포에서 돌연변이원에 의한 DNA 상해의 회복에 미치는 DNA 중합효소저해제의 영향)

  • 엄경일;선우양일;이천복;신은주
    • Environmental Mutagens and Carcinogens
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    • v.8 no.1
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    • pp.1-12
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    • 1988
  • The effects of aphidicolin (APC), an inhibitor of DNA polymerase alpha, or 2', 3'-dideoxythymidine 5'-triphosphate (ddTTP), an inhibitor of DNA polymerase beta, on the repair of DNA damage induced by ethyl methanesulfonate (EMS) or bleomycin (BLM) were investigated in Chinese hamster ovary (CHO)-K1 cells. Three assays were employed in this study: unscheduled DNA synthesis, alkaline elution and alkaline sucrose gradient sedimentation. It was shown that APC or ddTTP inhibited DNA induced by EMS, and thus, the post-treatment with APC or ddTTP following EMS treatment was resulted in the more amount of unscheduled DNA synthesis, and the more accumulation of DNA single-stand breaks than the cells post-incubated without APC or ddTTP. While, in the BLM induced DNA repair, only ddTTP inhibited DNA repair induced by BLM. And thus, the groups post-incubated with or without APC after BLM treatment had the same value in the amount of unscheduled DNA synthesis and of DNA single-strand breaks, while post-treatment with ddTTP was resulted in the increased amount of unscheduled DNA synthesis and the increased DNA sin -strand breaks than the group without ddTTP. These results suggested that both of DNA polymerase $\alpha$ and $\beta$ participated in the repair of DNA damage induced by EMS, but in BLM-induced DNA repair, polymerase $\beta$ participated.ipated.

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A Robust Pair-wise Key Agreement Scheme without Trusted Third Party and Pre-distributing Keys for MANET Environments (MANET에서 제 3 신뢰기관(TTP)과 사전 키 분배가 필요 없는 강인한 키 교환 방식)

  • Han, Seung-Jin;Choi, Jun-Hyeog
    • Journal of the Korea Society of Computer and Information
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    • v.13 no.5
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    • pp.229-236
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    • 2008
  • In this paper, re proposed scheme that it safely exchange encrypted keys without Trust Third Party(TTP) and Pre-distributing keys in ubiquitous environments. Existing paper assume that exist a TTP or already pre-distributed encrypted keys between nodes. However, there methods are not sufficient for wireless environments without infrastructure. Some existing paper try to use the Diffie-Hellman algorithm for the problem, but it is vulnerable to Replay and Man-in-the middle attack from the malicious nodes. Therefore, Authentication problem between nodes is solved by modified the Diffie-Hellman algorithm using ${\mu}TESLA$. We propose safe, lightweight, and robust pair-wise agreement algorithm adding. One Time Password(OTP) using timestamp to modified the Diffie-Hellman in ubiquitous environments, and verify a safety about proposed algorithm.

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Platelet-Agglutinating Protein p37 from a Patient with Thrombotic Thrombocytopenic Purpura Has Characteristics Similar to Prethrombin 2

  • Kim, Seung-Ho;Park, Soo-Jeong;Lee, Jong-Woo;Jin, Jong-Youl
    • BMB Reports
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    • v.35 no.5
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    • pp.524-531
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    • 2002
  • Thrombotic thrombocytopenic purpura (TTP) is characterized by widespread platelet thrombi in arterioles and capillaries. Unusually large or multimeric von Willebrand factor, as well as one or ore platelet-agglutinating factors, have been implicated in the pathogenesis of TTP. But, the actual mechanisms of platelet agglutination have not been satisfactorily explained. Recent studies suggested the 37-kDa platelet-agglutinating protein (PAP) p37 to be partially responsible for the formation of platelet thrombi in patients with TTP. We studied mobility in SDS-PAGE, the sequence of N-terminal amino acid residues, DNA and antigenic characteristics of PAP p37, which might be related to the pathogenesis of TTP. PAP p37 was purified from the plasma of a 31-year-old male Korean patient with acute TTP. The findings are as follows: (1) We compared PAP p37 with thrombin through the use of SDS-PAGE, either with or without $\beta$-mercaptoethanol. PAP p37 did not appear to be cleaved between the A- and B-chains of prethrombin 2. However, thrombin did cleave between those of prethrombin 2, but linked with disulfide bridge. (2) N-terminal 21 amino acid sequence of PAP p37 was T-F-G-S-G-E-A-D-X-G-L-R-P-L-F-E-K-K-S-L-E. It appeared to be identical to that of 285-305 amino acid residues of human prothrombin (prethrombin 2). (3) No prothrombin gene DNA mutation was revealed. (4). The antigenicity of PAP p37 was similar to thrombin, which was a result of the competitive binding against the anti-thrombin antibody. With these results, we conclude that PAP p37 has similar characteristics to prethrombin2.

A Ticket based Authentication and Payment Scheme for Third Generation Mobile Communications (3세대 이동 통신을 위한 티켓 기반 인증 및 지불 기법)

  • Lee, Byung-Rae;Chang, Kyung-Ah;Kim, Tai-Yun
    • Journal of KIISE:Information Networking
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    • v.29 no.4
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    • pp.368-374
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    • 2002
  • In the third generation mobile telecommunication systems such as UMTS, one of the important problems for value-added services is to check the recoverability of costs used by a mobile user. Previous authentication and payment schemes for value-added services by a mobile user across multiple service domains, rely on the concept of the on-line TTP, which serves as the users certification authority. In the third generation systems with many service providers, a wide range of services, and a diverse user population, authentication mechanisms with the on-line TTP provide a far from ideal solution. In this paper we present an efficient public-key protocol for mutual authentication and key exchange designed for value-added services in the third generation mobile telecommunications systems. The proposed ticket based authentication and payment protocol provides an efficient way for VASP to check the recoverability of costs without communication with the on-line TTP Furthermore, the proposed ticket based protocol can provide anonymous service usage for a mobile user.

A Robust Pair-wise Key Agreement Scheme based on Multi-hop Clustering Sensor Network Environments (멀티홉 클러스터 센서 네트워크 환경 기반에서 견고한 키 교환)

  • Han, Seung-Jin
    • Journal of the Korea Society of Computer and Information
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    • v.16 no.3
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    • pp.251-260
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    • 2011
  • In this paper, we proposed a scheme that it safely exchanges encrypted keys without Trust Third Party (TTP) and Pre-distributing keys in multi-hop clustering sensor networks. Existing research assume that it exists a TTP or already it was pre-distributed a encrypted key between nodes. However, existing methods are not sufficient for USN environment without infrastructure. Some existing studies using a random number Diffie-Hellman algorithm to solve the problem. but the method was vulnerable to Replay and Man-in-the-middle attack from the malicious nodes. Therefore, authentication problem between nodes is solved by adding a ��TESLA. In this paper, we propose a modified Diffie-Hellman algorithm that it is safe, lightweight, and robust pair-wise agreement algorithm by adding One Time Password (OTP) with timestamp. Lastly, authentication, confidentiality, integrity, non-impersonation, backward secrecy, and forward secrecy to verify that it is safe.

Detection of Malicious Node using Timestamp in USN Adapted Diffie-Hellman Algorithm (Diffie-Hellman 알고리즘이 적용된 USN에서 타임스탬프를 이용한 악의적인 노드 검출)

  • Han, Seung-Jin;Choi, Jun-Hyeog
    • The Journal of the Korea Contents Association
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    • v.9 no.1
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    • pp.115-122
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    • 2009
  • In this paper, we proposed scheme that we use a difference of timestamp in time in Ubiquitous environments as we use the Diffie-Hellman method that OTP was applied to when it deliver a key between nodes, and can detect a malicious node at these papers. Existing methods attempted the malicious node detection in the ways that used correct synchronization or directed antenna in time. We propose an intermediate malicious node detection way at these papers without an directed antenna addition or the Trusted Third Party (TTP) as we apply the OTP which used timestamp to a Diffie-Hellman method, and we verify safety regarding this. A way to propose at these papers is easily the way how application is possible in Ubiquitous environment.

Compact E-Cash with Practical and Complete Tracing

  • Lian, Bin;Chen, Gongliang;Cui, Jialin;He, Dake
    • KSII Transactions on Internet and Information Systems (TIIS)
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    • v.13 no.7
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    • pp.3733-3755
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    • 2019
  • E-cash has its merits comparing with other payment modes. However, there are two problems, which are how to achieve practical/complete tracing and how to achieve it in compact E-cash. First, the bank and the TTP (i.e., trusted third party) have different duties and powers in the reality. Therefore, double-spending tracing is bank's task, while unconditional tracing is TTP's task. In addition, it is desirable to provide lost-coin tracing before they are spent by anyone else. Second, compact E-cash is an efficient scheme, but tracing the coins from double-spender without TTP results in poor efficiency. To solve the problems, we present a compact E-cash scheme. For this purpose, we design an embedded structure of knowledge proof based on a new pseudorandom function and improve the computation complexity from O(k) to O(1). Double-spending tracing needs leaking dishonest users' secret knowledge, but preserving the anonymity of honest users needs zero-knowledge property, and our special knowledge proof achieves it with complete proofs. Moreover, the design is also useful for other applications, where both keeping zero-knowledge and leaking information are necessary.

The Concurrent Use of Rhus verniciflua Stokes as Complementary Therapy with Second or More Line Regimens on Advanced Non-small-cell Lung Cancer: Case Series

  • Lee, Sang-Hun;Kim, Kyung-Suk;Choi, Won-Cheol;Yoon, Seong-Woo
    • The Journal of Korean Medicine
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    • v.30 no.6
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    • pp.112-117
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    • 2009
  • Objective: Rhus verniciflua Stokes (RVS) has anticancer effect confirmed by preclinical studies and historical records. We thus tried to evaluate retrospectively the effect of RVS as a complementary medicine for patients with advanced non-small-cell lung cancer (NSCLC) showing refractory to conventional chemotherapy. Patients and Methods: From June 1, 2006 to June 30, 2007, patients with advanced NSCLC who received both the standardized RVS extract and a standard course of second or more line therapy such as pemetrexed ($Alimta^{(R)}$), erlotinib ($Tarceva^{(R)}$), and gefitinib ($Iressa^{(R)}$) were checked. A total of 13 patients were eligible for the final analysis after fulfilling inclusion/exclusion criteria. Time to progression (TTP) of these patients treated with the standardized RVS extract was checked in the aftercare period. Results: Patients received RVS treatment for a median period of 296 (range 84-698) days. The median TTP was 220.5 (range 36-489) days, and three patients (23.1%) had TTP values of 15 more months. No significant side effects from RVS treatment have been observed. Conclusion: The standardized RVS extract might have synergetic effects by assisting apoptosis in advanced NSCLC with concurrent standard therapy agents, since it prolonged TTP without significant adverse effects. This study suggests that the standardized RVS extract is beneficial to patients with chemotherapy-refractory NSCLC. Further clinical trials and preclinical studies are necessary to determine the efficacy and safety of the standardized RVS extract in NSCLC.

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Monitoring Posterior Cerebral Perfusion Changes With Dynamic Susceptibility Contrast-Enhanced Perfusion MRI After Anterior Revascularization Surgery in Pediatric Moyamoya Disease

  • Yun Seok Seo;Seunghyun Lee;Young Hun Choi;Yeon Jin Cho;Seul Bi Lee;Jung-Eun Cheon
    • Korean Journal of Radiology
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    • v.24 no.8
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    • pp.784-794
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    • 2023
  • Objective: To determine whether dynamic susceptibility contrast-enhanced (DSC) perfusion magnetic resonance imaging (MRI) can be used to evaluate posterior cerebral circulation in pediatric patients with moyamoya disease (MMD) who underwent anterior revascularization. Materials and Methods: This study retrospectively included 73 patients with MMD who underwent DSC perfusion MRI (age, 12.2 ± 6.1 years) between January 2016 and December 2020, owing to recent-onset clinical symptoms during the follow-up period after completion of anterior revascularization. DSC perfusion images were analyzed using a dedicated software package (NordicICE; Nordic NeuroLab) for the middle cerebral artery (MCA), posterior cerebral artery (PCA), and posterior border zone between the two regions (PCA-MCA). Patients were divided into two groups; the PCA stenosis group included 30 patients with newly confirmed PCA involvement, while the no PCA stenosis group included 43 patients without PCA involvement. The relationship between DSC perfusion parameters and PCA stenosis, as well as the performance of the parameters in discriminating between groups, were analyzed. Results: In the PCA stenosis group, the mean follow-up duration was 5.3 years after anterior revascularization, and visual disturbances were a common symptom. Normalized cerebral blood volume was increased, and both the normalized time-topeak (nTTP) and mean transit time values were significantly delayed in the PCA stenosis group compared with those in the no PCA stenosis group in the PCA and PCA-MCA border zones. TTPPCA (odds ratio [OR] = 6.745; 95% confidence interval [CI] = 2.665-17.074; P < 0.001) and CBVPCA-MCA (OR = 1.567; 95% CI = 1.021-2.406; P = 0.040) were independently associated with PCA stenosis. TTPPCA showed the highest receiver operating characteristic curve area in discriminating for PCA stenosis (0.895; 95% CI = 0.803-0.986). Conclusion: nTTP can be used to effectively diagnose PCA stenosis. Therefore, DSC perfusion MRI may be a valuable tool for monitoring PCA stenosis in patients with MMD.

Evaluation of Empirical Porous-Media Parameters for Numerical Simulation of Wave Pressure on Caisson Breakwater Armored with Tetrapods (테트라포드 피복 케이슨 방파제 파압 수치모의를 위한 투수층 경험계수 산정)

  • Lee, Geun Se;Oh, Sang-Ho;Yoon, Sung Bum
    • Journal of Korean Society of Coastal and Ocean Engineers
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    • v.31 no.6
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    • pp.344-350
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    • 2019
  • In this study, waves2Foam implemented in OpenFOAM is used to simulate numerically the wave pressure on a verical caisson under the condition of with and without the placement of Tetrapods in front of the caisson. The comparisons of the numerical results and the experimental data show fairly good agreement between them. Based on this, it is possible to suggest an optimal combination of coefficients for an empirical formula to represent the protective TTP layer as porous media.