• Title/Summary/Keyword: Mechanism and Factor

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New Retention Mechanism of Mononucleotides with Buffer Concentrations in Ion-suppressing RP-HPLC

  • Lee, Ju-Weon;Row, Kyung-Ho
    • Biotechnology and Bioprocess Engineering:BBE
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    • v.6 no.1
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    • pp.37-41
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    • 2001
  • HPLC separation of ionic samples tends to be more complicated and difficult to understand than that of non-ionic compounds. On the other hand, band spacing is much more easily manipulated for ionic than for neutral samples. Ion-suppression RP-HPLC method was used with organic modifier and aqueous buffer solution. In this work, five mononucleotides of cytidine-5-monophosphate (5-CMP) disodium salt, uridine-5-monophosphate disodium salt (5-UMP), guanosine-5-monophosphate disodium salt (5-GMP), inosine-5-monophosphate disodium salt (5-IMP), and adenosine-5-monophosphate disodium salt (5-AMP) were examined. Acetic acid and sodium phosphate were used as buffers, and methanol as an organic modifier. A new relationship between the retention factor and the buffer concentration at a fixed modifier content (5% of methanol) could be expressed by following: K = (k(sub)-1 + k(sub)0 (k(sub)B/k(sub)S)/(1 + (k(sub)B/k(sub)S) C(sub)B(sup)a), where C(sub)B was the concentration of buffer. Using this relationship, the calculated values closely matched the experimental data. The derived relationship showed that as the buffer concentration increased, the retention factor approached a certain value, and this was buffer dependent.

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Role of HIV Vpr as a Regulator of Apoptosis and an Effector on Bystander Cells

  • Moon, Ho Suck;Yang, Joo-Sung
    • Molecules and Cells
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    • v.21 no.1
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    • pp.7-20
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    • 2006
  • The major event in human immunodeficiency virus type 1 (HIV-1) infection is the death of many cells related to host immune response. The demise of these cells is normally explained by cell suicide mechanism, apoptosis. Interestingly, the decrease in the number of immune cells, such as non-CD4+ cells as well as CD4+ T cells, in HIV infection usually occurs in uninfected bystander cells, not in directly infected cells. It has, therefore, been suggested that several soluble factors, including viral protein R (Vpr), are released from the infected cells and induce the death of bystander cells. Some studies show that Vpr interacts directly with adenine nucleotide translocator (ANT) to induce mitochondrial membrane permeabilization (MMP). The MMP results in release of some apoptogenic factors such as cytochrome-c (cyt-c) and apoptosis-inducing factor (AIF). Vpr also has indirect effect on mitochondria through enhancing the level of caspase-9 transcription and suppressing nuclear factor-kappa B (NF-${\kappa}B$). The involvement of p53 in Vpr-induced apoptosis remains to be studied. On the other hand, low level of Vpr expression has anti-apoptotic effect, whereas it's high level of expression induces apoptosis. Extracellular Vpr also exhibits cytotoxicity to uninfected bystander cells through apoptotic or necrotic mechanism. The facts that Vpr has cytotoxic effect on both infected cells and bystander cells, and that it exhibits both proand anti-apoptotic activity may explain its role in viral survival and disease progression.

The Anti-inflammatory Mechanism of Protaetia brevitarsis Lewis via Suppression the Activation of NF-κB and Caspase-1 in LPS-stimulated RAW264.7 Cells

  • Myung, Noh-Yil;Ahn, Eun-Mi;Kim, Su-Jin
    • Biomedical Science Letters
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    • v.26 no.4
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    • pp.267-274
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    • 2020
  • The larva of Protaetia brevitarsis Lewis (P. brevitarsis), edible insect, is traditionally consumed as alternative source of nutrients and has various health benefits. However, the exact pharmaceutical effects of P. brevitarsis on inflammatory response are still not well understood. Thus, we investigated the anti-inflammatory effects and mechanisms of P. brevitarsis in lipopolysaccharide (LPS)-stimulated RAW264.7 cells. We investigated the effects of P. brevitarsis on the expression levels of inflammatory-related genes, including inflammatory cytokines, prostaglandin E2 (PGE2), cyclooxygenase (COX)-2 and inducible nitric oxide synthase (iNOS) in LPS-stimulated RAW264.7 cells. To understand the anti-inflammatory mechanism of P. brevitarsis, we explored the regulatory effect of P. brevitarsis on nuclear factor (NF)-κB and caspase-1 activation. The findings of this study demonstrated that P. brevitarsis inhibits the LPS-induced inflammatory cytokine and PGE2 levels, as well as COX-2 and iNOS expression. Moreover, we confirmed that the anti-inflammatory effect of P. brevitarsis occurs via suppression of the activation of NF-κB and caspase-1. Conclusively, these findings provide experimental evidence that P. brevitarsis may be useful candidate for the treatment of inflammatory-related diseases.

A Study on the Effect of Processor Stack Frame Mechanism on Secure Programming in C Language (C 언어에서 프로세서의 스택관리 형태가 프로그램 보안에 미치는 영향)

  • 이형봉;차홍준;노희영;이상민
    • The KIPS Transactions:PartC
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    • v.8C no.1
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    • pp.1-11
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    • 2001
  • There are several traditional factors of software quality. Some of them are such as correctness, reliability, efficiency, compatibility, portability, etc. In addition to them, security is required as another factor of software quality nowadays because some application programs are used as a way to attack information systems by stack frame manipulation. Each processor has its own peculiar stack frame mechanism and C language uses the characteristics of them. This paper explains the concept of security problem caused by stack frame manipulation, and the stack frame mechanism of Pentium, Alpha and SP ARC processor in detail. And then it examines the effect of stack frame mechanism on the security of programs in C language.

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Presteady State Kinetics of ATP Hydrolysis by Escherichia coli Rho Protein Monitors the Initiation Process

  • Jeong, Yong-Ju;Kim, Dong-Eun
    • Bulletin of the Korean Chemical Society
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    • v.27 no.2
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    • pp.224-230
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    • 2006
  • Escherichia coli transcription termination factor Rho catalyzes the unwinding of RNA/DNA duplex in reactions that are coupled to ATP binding and hydrolysis. We report here the kinetic mechanism of presteady state ATP binding and hydrolysis by the Rho-RNA complex. Presteady state chemical quenched-flow technique under multiple turnover condition was used to probe the kinetics of ATP binding and hydrolysis by the Rho-RNA complex. The quenched-flow presteady state kinetics of ATP hydrolysis studies show that three ATPs are bound to the Rho-RNA complex with a rate of $4.4\;{\times}\;10^5M^{-1}s^{-1}$, which are subsequently hydrolyzed at a rate of $88s^{-1}$ and released during the initiation process. Global fit of the presteady state ATP hydrolysis kinetic data suggests that a rapid-equilibrium binding of ATP to Rho-RNA complex occurs prior to the first turnover and the chemistry step is not reversible. The initial burst of three ATPs hydrolysis was proposed to be involved in the initialization step that accompanies proper complex formation of Rho-RNA. Based on these results a kinetic model for initiation process for Rho-RNA complex was proposed relating the mechanism of ATP binding and hydrolysis by Rho to the structural transitions of Rho-RNA complex to reach the steady state phase, which is implicated during translocation along the RNA.

Axial load-strain relationships of partially encased composite columns with H-shaped steel sections

  • Bangprasit, Papan;Anuntasena, Worakarn;Lenwari, Akhrawat
    • Steel and Composite Structures
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    • v.45 no.1
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    • pp.51-66
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    • 2022
  • This paper presents the axial compression behavior of partially encased composite (PEC) columns using H-shaped structural steel. In the experimental program, a total of eight PEC columns with H-shaped steel sections of different flange and web slenderness ratios were tested to investigate the interactive mechanism between steel and concrete. The test results showed that the PEC columns could sustain the load well beyond the peak load provided that the flange slenderness ratio was not greater than five. In addition, the previous analytical model was extended to predict the axial load-strain relationships of the PEC columns with H-shaped steel sections. A good agreement between the predicted load-strain relationships and test data was observed. Using the analytical model, the effects of compressive strength of concrete (21 to 69 MPa), yield strength of steel (245 to 525 MPa), slenderness ratio of flange (4 to 10), and slenderness ratio of web (10 to 25) on the interactive mechanism (Kh = confinement factor for highly confined concrete and Kw = reduction factor for steel web) and ductility index (DI = ratio between strain at peak load and strain at proportional load) were assessed. The numerical results showed that the slenderness of steel flange and yield strength of steel significantly influenced the compression behavior of the PEC columns.

Insulin-Like Growth Factor-I Induces Androgen Receptor Activation in Differentiating C2C12 Skeletal Muscle Cells

  • Kim, Hye Jin;Lee, Won Jun
    • Molecules and Cells
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    • v.28 no.3
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    • pp.189-194
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    • 2009
  • The modulating effect of IGF-I on the regulation of AR gene expression and activation in skeletal muscle cells remains poorly understood. In this study, the effects of IGF-I treatment on AR induction and activation in the absence of AR ligands were examined. Differentiating C2C12 cells were treated with different concentrations (0-250 ng/ml) of IGF-I or for various periods of time (0-60 min) of 250 ng/ml IGF-I. Treatment of C2C12 cells with IGF-I resulted in a dose- and time-dependent increase in total AR and phosphorylated AR (Ser 213). IGF-I treatment also led to significantly increased AR mRNA expression when compared with the control. The levels of skeletal ${\alpha}-actin$ and myogenin mRNA, known target genes of AR, were also significantly upregulated after 5 or 10 min of treatment with IGF-I. Confocal images revealed that IGF-I stimulated nuclear localization of AR in the absence of ligands. In addition, an electrophoretic mobility shift assay indicated that IGF-I stimulated the AR DNA binding activity in a time-dependent manner. The present results suggest that IGF-I stimulates the expression and activation of AR by ligand-independent mechanism in differentiating C2C12 mouse skeletal muscle cells.

A New Mechanism for Enhanced Beat Transport of Nanofluid (나노유체의 열전도도 향상에 관한 새로운 메커니즘)

  • Lee Dong-Geun;Kim Jae-Won
    • Transactions of the Korean Society of Mechanical Engineers B
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    • v.30 no.6 s.249
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    • pp.560-567
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    • 2006
  • Although various conjectures have been proposed to explain abnormal increase in thermal conductivity of nanofluids, the detailed mechanism could not be understood and explained yet. The main reason is primarily due to the lack of knowledge on the most fundamental factor governing the mechanisms such as Brownian motion, liquid layering, phonon transport, surface chemical effects and agglomeration. By applying surface complexation model for the measurement data of hydrodynamic size, zeta potential, and thermal conductivity, we have shown that sulfate charge state is mainly responsible for the increase in the present condition and may be the factor incorporating all the mechanisms as well. Moreover, we propose a new model including concepts of fractal and interfacial layer. The properties such as thickness and thermal conductivity of the layer are estimated from the surface charge states and the concept of electrical double layer. With this, we could demonstrate the pH dependences of the layer properties and eventually of the effective thermal conductivity of the nanofluid.

Design of Reliable Adaptive Filter with Fault Tolerance Using TMS320C32 (TMS320C32를 이용한 고장허용을 갖는 신뢰 적응 필터 설계)

  • Ryoo, Dong-Wan;Seo, Bo-Hyeok
    • Proceedings of the KIEE Conference
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    • 2000.07d
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    • pp.2429-2432
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    • 2000
  • Adaptive filter algorithm has been used for plant identifier and noise cancellation. This algorithm has been researched for performance enhancement of filtering. The design and development of a reliable system has been becoming a key issue in industry field because the reliability of a system is considered as an important factor to perform the system's function successfully. And the computing with reliability and fault tolerance is a important factor in the case of aviation and nuclear plant. This paper presents design of reliable adaptive filter with fault tolerance. Generally, redundancy is used for reliability. In this case it needs computing or circuit for voting mechanism or computing for fault detection or switching part. But this presented Filter is not in need of computing for voting mechanism, or fault detection. Therefore it has simple computing, and practicality for application. And in this paper, reliability of adaptive filter is analyzed. The effectiveness of the proposed adaptive filter is demonstrated to the case studies of plant identifier and noise cancellation by using DSP.

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The Ameliorative Effect of Rubi Fructus on DSS-induced Colitis in Mice

  • Myung, Noh-Yil
    • Korean Journal of Plant Resources
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    • v.34 no.3
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    • pp.216-222
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    • 2021
  • Ulcerative colitis (UC) is an inflammatory bowel disease and a chronic gastrointestinal disorder. Rubi Fructus (RF), the fruit of Rubus coreanus Miquel, is known to exert several pharmacological effects including anti-oxidative, anti-obesity and anti-inflammatory properties. However, the improving effect and mechanism of RF on intestinal inflammation is not been fully understood. The purpose of this study was to investigate the regulatory effect of RF on dextran sulfate sodium (DSS)-induced colitis in mice. We evaluated the effects of RF on DSS-induced clinical signs by analyzing weight loss and colon length. The inhibitory effects of RF on inflammatory mediators such as prostaglandin E2 (PGE2), cyclooxygenase (COX)-2, as well as the activation of nuclear factor-κB (NF-κB), were determined in colitis tissue. Our data indicated that mice treated with DSS showed clinical symptoms of colitis, including weight loss, colon length decrease and diarrhea. However, we observed that RF treatment significantly improved these clinical symptoms of weight loss, colon length decrease and diarrhea induced by DSS. RF inhibited the enhanced levels of COX-2 and PGE2 caused by DSS. We also showed that the anti-inflammatory mechanism of RF by suppressing the activation of NF-kB in DSS-treated colon tissues. Collectively, the findings of this study indicate the prospect of developing new drugs from RF for UC treatment.