• Journal of the Korean Institute of Telematics and Electronics B
• /
• v.33B no.2
• /
• pp.209-216
• /
• 1996

This paper deals with the speed control of the switched reluctnace motor using fuzzy PI controller. A fuzzy logic control provides a good approach to nonlinear system because it does not require a detailed mathematical model to formulate the algorithm. The fuzzy PI controller is implemented by MCS80C196KB, a 16 bit one-chip microcontroller, and an EPROM is used for the commutation logic of the SRM. The simulation and experimental results show that the performance of the fuzzy PI controller is superior to that of the conventional PI controller in terms of response time, settling time and overshoot. In particular, the robustness of the system is largely improved.

• Macromolecular Research
• /
• v.15 no.2
• /
• pp.173-177
• /
• 2007

Living anionic and cationic polymerizations have been combined to prepare various types of comb-like copolymers composed of polystyrene (PS) and polyisoprene (PI) blocks, with a precisely controlled architecture. According to the relative placement of these elementary building blocks, combs with randomly distributed PS and PI or with poly(styrene-b-isoprene) diblock branches (I & II, respectively) can be prepared. The reaction procedure initially includes the synthesis of a poly(chloroethylvinyl ether) using living cationic polymerization, which is used as the reactive backbone to successively graft $PS^-Li^+$ and $PI^-Li^+$ or $PI-b-PS^-Li^+$ to obtain structures (I) or (II). The synthesis of Janus-type PS-comb-b-PI-combs (III) initially involves the synthesis of a diblock backbone using living cationic polymerization, which bears two distinct reactive functions having either a protected or activated form. Living $PS^-Li^+$ and $PI^-Li^+$ are then grafted, in two separate steps, onto each of the reactive functions of the backbone, respectively.

• Korean Journal of Veterinary Research
• /
• v.44 no.3
• /
• pp.433-439
• /
• 2004

This study was carried out to investigate the efficacy of rifampin with or without streptomycin in male Sprague-Dawley (SD) rats experimentally inoculated with Brucella abortus. Thirty rats were intraperitoneally inoculated with $1.0{\times}10^9$colony-forming units of B. abortus. They were divided into 3 groups by treatment with antibiotic. 10 rats in Group A were orally administrated with rifampin, 10 rats in Group B with rifampin orally and with streptomycin intramuscularly over 12 weeks starting at 1 week post infection (PI). A placebo recipient in Group C was inoculated with sterile saline without antibiotics. All animals were monitored by tube agglutination test (TAT) and AMOS-PCR to evaluate the efficiency of the antibiotics to B. abortus infection. The antibody titers in Groups A, B and C were 1:400, 1:400 and 1:800 as measured by TAT at the first week PI, respectively. The antibody titer in Group A decreased to 1:100 by the 13th week PI. That in the control group was observed as high antibody titer until 13th weeks PI, but the antibody response in Group B was low(1:50) from the 5th week to the 13th week PI. AMOS-PCR there was evidence of relapse of B. abortus in group A in liver and spleen specimens at the 13th week PI. B. abortus DNA was detected in Group C in liver and spleen specimens from the 1st week to 13th week PI by AMOS-PCR. However AMOS-PCR could not detect any organism in Group B from the 3rd week PI until the end of the study. This study demonstrated that administration of a combination of rifampin and streptomycin was more efficacious than administration of rifampin alone. A significant reduction in antibody titer was observed when a combination of 15 mg/kg/day of rifampin per os and 15 mg/kg/day streptomycin intramuscularly was used in comparison with the antibody of control group.

• Journal of Advanced Marine Engineering and Technology
• /
• v.32 no.1
• /
• pp.147-152
• /
• 2008

This paper has been fabricated the two different type of variable attenuators using a characteristics of a 3 dB directional coupler and pin diodes. One was not analyzed using the conventional even-odd modes but used simple two-port techniques. The resulting scattering parameters described operation characteristics for the general case where the terminating impedances are equal and unequal. After analyzing resistor role of the ${\pi}$ type fixed attenuator. this paper used a pin diode instead of a resistor. The variable attenuators were fabricated using pin diodes for current-controlled attenuation on the coupled ports of a 3 dB branch-line coupler and ${\pi}$ type fixed attenuator. The realized variable attenuators have more than 33 dB attenuation ranges at 2.1 GHz. and the input and output reflection coefficients are less than -13 dB. These results could be applied to mobile communication systems. It can be varied gain of the power amplifier according to change a outdoor environmental temperature and improved linearity.

• Molecules and Cells
• /
• v.26 no.1
• /
• pp.48-52
• /
• 2008

We here demonstrate an anti-inflammatory action of raloxifene, a selective estrogen receptor modulator, in lipopolysaccharide (LPS)-induced murine macrophage RAW264.7 cells. Treatment with raloxifene at micromolar concentrations suppressed the production of nitric oxide (NO) by down-regulating expression of the inducible nitric oxide synthase (iNOS) gene in LPS-activated cells. The decreased expression of iNOS and subsequent reduction of NO were due to inhibition of nuclear translocation of transcription factor NF-${\kappa}B$. These effects were significantly inhibited by exposure to the phosphatidylinositol 3-kinase (PI 3-kinase) inhibitor, LY294002, or by expression of a dominant negative mutant of PI 3-kinase. In addition, pretreatment with raloxifene reduced LPS-induced Akt phosphorylation as well as NF-${\kappa}B$ DNA binding activity and NF-${\kappa}B$-dependent reporter gene activity. Thus our findings indicate that raloxifene exerts its anti-inflammatory action in LPS-stimulated macrophages by blocking the PI 3-kinase-Akt-NF-${\kappa}B$ signaling cascade, and eventually reduces expression of pro-inflammatory genes such as iNOS.

• Journal of the Korean Magnetics Society
• /
• v.7 no.6
• /
• pp.299-307
• /
• 1997

NdFeB films have been grown onto Si(100) substrate by a KrF pulsed laser ablation of the targets of $Nd_xFe_{90.98-x}B_{9.02}$ (x=17.51~27.51) at the substrate temperature of 620~700 $^{\circ}C$ and the laser beam energy density of 2.75~5.99 J/$\textrm{cm}^2$. The films exhibit no preferred orientation, however, good hard magnetic properties were produced from as-deposited condition : $4{\pi}M_s$=7 kG, $4{\pi}M_r$=4 kG, and $H_c$=300~1000 Oe. The depositon rate was not greatly influenced by changing the substrate temperature, but it increases linearly by increasing the beam energy density. The beam energy density of 3 J/$\textrm{cm}^2$ gave the optimal condition to have the highest $4{\pi}M_r$ and $H_c$ as well. The higher content of Nd induces a higher coercivity and $4{\pi}M_r$ at the same time without prominent change in $4{\pi}M_s$.

• IMMUNE NETWORK
• /
• v.11 no.2
• /
• pp.123-133
• /
• 2011

Background: Mycobacterium tuberculosis (Mtb) heparin binding hemagglutinin (HBHA) is an Ag known to evoke effective host immune responses during tuberculosis infection. However, the molecular basis of the host immune response to HBHA has not been fully characterized. In this study, we examined the molecular mechanisms by which HBHA can induce the expression of proinflammatory cytokines in macrophages. Methods: HBHA-induced mRNA and protein levels of proinflammatory cytokines were determined in bone marrow-derived macrophages (BMDMs) using RT-PCR and ELISA analysis. The roles of intracellular signaling pathways for NF-${\kappa}B$, PI3-K/Akt, and MAPKs were investigated in macrophage proinflammatory responses after stimulation with HBHA. Results: HBHA robustly activated the expression of mRNA and protein of both TNF-${\alpha}$ and IL-6, and induced phosphorylation of NF-${\kappa}B$, Akt, and MAPKs in BMDMs. Both TNF-${\alpha}$ and IL-6 production by HBHA was regulated by the NF-${\kappa}B$, PI3-K, and MAPK pathways. Furthermore, PI3-K activity was required for the HBHA-induced activation of ERK1/2 and p38 MAPK, but not JNK, pathways. Conclusion: These data suggest that mycobacterial HBHA significantly induces proinflammatory responses through crosstalk between the PI3-K and MAPK pathways in macrophages.

• Proceeding of EDISON Challenge
• /
• 2014.03a
• /
• pp.385-397
• /
• 2014

신약을 개발하거나 단백질 구조를 예측하는데 Molecular Mechanics (MM)의 방법을 사용한다. 하지만, MM 만으로는 자연현상에서 일어나는 결과를 정확하게 기술하기 어렵다. 본 연구는 기존의 MM 방법으로는 정확히 예측이 불가능한 비 공유결합 중 하나인 ${\pi}-{\pi}$ interaction을 양자역학 계산을 통해 정확한 예측이 가능한지 보았다. ${\pi}-{\pi}$ interaction 이란 생체 내, 의약 화합물에서 발견되는 결합이기 때문에, 단백질과 결합하는 구조의 예측이 중요하다고 할 수 있다. 본 실험은 ${\pi}-{\pi}$ interaction을 갖는 Sandwich, T shape, 그리고 Parallel displaced 세 가지 모형을 가지고 양자역학 계산을 수행하였다. 양자역학 계산은 DFT의 세가지 함수 M06_2X, M05_2X, B3LYP를 이용하였다. 실험결과에서 세 가지 함수가 각기 다른 결과를 보였는데, M06_2X의 결과에서 ${\pi}-{\pi}$ interaction을 더 정확하게 계산하였다. 이러한 결과를 바탕으로, 양자역학의 방법을 통해 MM에서는 예측이 불가능한 ${\pi}-{\pi}$ interaction을 계산 할 수 있고 이 부분을 고려하여 화합물 간의 결합구조를 예측을 향상시킬 수 있다.

• Journal of Life Science
• /
• v.34 no.2
• /
• pp.94-104
• /
• 2024

β-Lapachone is a natural quinone compound originally obtained from the bark of the lapacho tree (Tabebuia vellanedae), which has been used in traditional medicine in several South and Central American countries for treating various diseases. Although β-lapachone has been reported to have potent anticancer activity in many types of cancer cells, its effect on the proliferation of hepatocellular carcinoma (HCC) cells is still unclear. Therefore, in this study, we investigated the effect of β-lapachone on the proliferation of human HCC Hep3B cells. According to our results, the decrease in cell viability of Hep3B cells caused by β-lapachone was closely related to the induction of apoptosis, which was confirmed through changes in nuclear morphology and flow cytometry. In addition, in Hep3B cells treated with β-lapachone, the expression of Bcl-2, an anti-apoptotic factor, was decreased, while the expression of Bax, an apoptosis inducer, was increased, and the activity of the caspase cascade was also increased. However, in the presence of a pan-caspase inhibitor, β-lapachone-induced apoptosis was weakened, indicating that the induction of apoptosis by β-lapachone was caspase-dependent. Moreover, β-lapachone treatment activated extracellular-regulated kinase (ERK) signaling while inhibiting activation of the phosphoinositide 3 kinase (PI3K)/Akt pathway. Furthermore, the effect of the ERK inhibitor on suppressing the induction of apoptosis by β-lapachone was minimal, and the PI3K inhibitor significantly increased β-lapachone-induced apoptosis. The findings from this study will contribute to a better understanding of the anticancer activity of β-lapachone in HCC cells.

• Bulletin of the Korean Mathematical Society
• /
• v.40 no.1
• /
• pp.91-99
• /
• 2003

In this paper, we show that if the ring of a Merits context (A, B, M, N, ${\psi},\;{\phi}$) with zero pairings is a strongly $\pi$-regular ring of bounded index if and only if so are A and B. Furthermore, we extend this result to the ring of a Merits context over quasi-duo strongly $\pi$-regular rings.