• Journal of Plant Biology
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• 제31권2호
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• pp.91-100
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• 1988

The effect of Ca2+ and polyamines on the activity $\beta$-glucan synthetase II(GSII) related to cell wall synthesis was studied in carrot suspension cultured cells. The activity of GS II is four times higher than that of $\beta$-glucan synthetase I in carrot suspension cultured cells and in vitro expreiment, the activity of GSII was increased in response to increase in concentration of Ca2+ and polyamines. When carrot suspension cultured cells were incubated together with Ca2+ and polyamines, the GSII activity was high at 0.1mM of Ca2+ and 1mM of putrescine. Also, polycationic poly-L-lysine and poly-L-ornithine increased about 50% the GSII activity than that of the control, respectively. These results may imply that Ca2+ and polyamines were related to the enzyme activity as a polycationic nature. In addition, verapamil as the calcium channel blocker and flunarizine as an antagonist of calcium mechanism in cytoplasm decreased GSII activity ramarkably, Ca2+ and calmodulin stimulated GSII activity as Ca2+ of free ion rather than Ca2+ calmodulin complex. The effect of 2,4-D on the GSII activity in culture medium is shown to be low at 0.1mg per liter and GSII activity increased about 30% more than that of the 0.1mg/l at the range of 0.3-1.0mg per litere. Cummulative results suggest that Ca2+ and polyfamines stimulate the cell wall synthesis by means of the enhancement of GSII activity responsible for synthesizing the cell wall components.

• 대한전자공학회논문지SD
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• 제38권1호
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• pp.69-78
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• 2001

본 논문은 휴대용 고속 페이징 시스템을 위한 FLEXTM 프로토콜 신호 처리기의 설계 및 FPGA 구현에 관한 것이다. 본 논문에서는 A/D 변환기의 입력 단에서 수신된 interleaved 4-level 비트 심볼 데이터의 동기를 위한 심볼 동기 알고리듬과 (31,21)BCH 부호에 대해 실시간 2중 오류정정이 가능한 개선된 복호 알고리듬을 제안한다. 설계된 프로토콜 신호처리기는 6개의 기능 모듈로 구성되어 있으며, 각 모듈은 VHDL(VHSIC Hardware Description Language)로 모델링을 행하였다. 제안된 프로토콜 신호기는 Axil-320 워크스테이션 상에서 Synopsys/sup TM/툴을 이용하여 기능 시뮬레이션 및 논리합성(Altera 10K 라이브러리 이용)을 수행하였다. 논리합성 결과 전체 셀의 수는 약 2,631이었다 또한, 설계된 FPGA 칩의 설계검증을 위하여 Altera MAX+ PLUS Ⅱ 상에서 타이밍 시뮬레이션을 수행하였다. PCB 상에서 testbed를 구축한 후, Logic Analyzer를 이용하여 제작된 FPGA 칩의 동작상태를 확인하였고, 실험을 통하여 제작된 칩이 정확히 동작함을 확인하였다.

• 대한수의학회지
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• 제36권3호
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• pp.599-605
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• 1996

This study was designed to examine the mechanism of penile erection in adult bull by analyzing the responses of bovine proximal retractor penile muscle strips(BRP) to electtical field stimulation(EFS), exogenous nitric oxide(NO), NO synthesis precursor(L-arginine), NO synthase inhibitors(L-NAME, L-NMMA), guanylate cyclase inhibitor(methylene blue) and nonspecific potassium channel blocker(tetraethylammonium, TEA) treatments. Isometric tension of BRP was measured using physiograph. Results were summarized as follows: 1. EFS of nonadrenergic noncholinrgic(NANC) nerve in BRP produced frequency-dependent inhibitory responses to the contraction induced by co-treatment of epinephrine, guanethidine and atropine. The inhibitory responses to EFS were blocked by tetrodotoxin(TTX, $1{\mu}M$). 2. Treatment of L-NAME ($10,\;20{\mu}M$) inhibited the relaxation to EFS whereas L-NMMA ($100{\mu}M$) had no effect. 3. Treatment of NO($20,\;40{\mu}M$; as an acidified solution of $NaNO_2$) induced concentration-dependent relaxation whereas preincubation of TTX($1{\mu}M$) and L-NAME($20{\mu}M$) had no effect on the relaxation response. 4. L-arginine treatment(10mM) blocked the inhibitory effect of L-NAME($20{\mu}M$). 5. Pretreatment of methylene blue($40{\mu}M$) reduced the NANC-induced relaxation of BRP. 6. Tetraethylammonium(TEA, 80mM) reduced NANC relaxation. These results suggest that NO may act as a NANC neurotransmitter in BRP and the effects might be mediated by cGMP and potassium channel.

• Bulletin of the Korean Chemical Society
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• 제34권2호
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• pp.482-488
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• 2013

Two piperazine-containing 3,4-dihyroquinazolines (BK10007S/8S) have been synthesized, based on our previous work on the synthesis and antitumoral activity of 3,4-dihyroquinazolines. After evaluating them for T-type calcium channel blocking effect and in vitro anti-cancer effect, they were profiled for acute and repeat dose toxicity (40 mg/kg, 2 weeks) to BALB/c mice. BK10007S/8S were further in vivo evaluated against human pancreatic MIA PaCa-2 carcinoma in $BALB/c^{nu/nu}$ nude mice, which exhibited 54 and 61% tumor growth inhibition through 57-day oral administration of 2 mg/kg of body weight, respectively.

• The Korean Journal of Physiology and Pharmacology
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• 제25권1호
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• pp.87-94
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• 2021

Skin photoaging occurs due to chronic exposure to solar ultraviolet radiation (UV), the main factor contributing to extrinsic skin aging. Clinical signs of photoaging include the formation of deep, coarse skin wrinkles and hyperpigmentation. Although melanogenesis and skin wrinkling occur in different skin cells and have different underlying mechanisms, their initiation involves intracellular calcium signaling via calcium ion channels. The ORAI1 channel initiates melanogenesis in melanocytes, and the TRPV1 channel initiates MMP-1 production in keratinocytes in response to UV stimulation. We aimed to develop a drug that may simultaneously inhibit ORAI1 and TRPV1 activity to help prevent photoaging. We synthesized nootkatol, a chemical derivative of valencene. TRPV1 and ORAI1 activities were measured using the whole-cell patch-clamp technique. Intracellular calcium concentration [Ca2+]i was measured using calcium-sensitive fluorescent dye (Fura-2 AM). UV-induced melanin formation and MMP-1 production were quantified in B16F10 melanoma cells and HaCaT cells, respectively. Our results indicate that nootkatol (90 μM) reduced TRPV1 current by 94% ± 2% at -60 mV and ORAI1 current by 97% ± 1% at -120 mV. Intracellular calcium signaling was significantly inhibited by nootkatol in response to ORAI1 activation in human primary melanocytes (51.6% ± 0.98% at 100 μM). Additionally, UV-induced melanin synthesis was reduced by 76.38% ± 5.90% in B16F10 melanoma cells, and UV-induced MMP-1 production was reduced by 59.33% ± 1.49% in HaCaT cells. In conclusion, nootkatol inhibits both TRPV1 and ORAI1 to prevent photoaging, and targeting ion channels may be a promising strategy for preventing photoaging.

• 한국가스학회지
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• 제21권4호
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• pp.92-102
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• 2017

피셔-트롭쉬 합성반응은 CO와 H2의 혼합가스로 이루어진 합성가스를 부가가치가 높은 탄화수소 제품으로 변환시킨다. 본 논문에서는 저온 피셔-트롭쉬 합성반응과 단일, 다중 마이크로채널 반응기에 패킹시킨 촉매를 기반으로 강화된 반응조건의 열전달을 고려하여 전산유체역학 기반의 시뮬레이션을 진행하고 분석하였다. 단일채널모델을 통하여 CO 전환률이 ~65% 이상, $C_{5+}$ 선택도가 ~74% 이상을 달성하면서도 Co 기반의 super-active 촉매를 통해 GHSV를 $30000hr^{-1}$을 달성할 수 있음을 보였다. 다중 마이크로채널 반응기모델에서는 열전달 시뮬레이션을 동시에 해석하여, 3가지의 다른 반응기구조에 대해서, 직교류 wall boiling 냉매를 사용시 ${\Delta}T_{max}$가 23 K였으며 평행유동 subcooled 냉매와 평행유동 wall boiling 냉매의 경우 각각 15 K와 13 K의 ${\Delta}T_{max}$를 보였다. 반응기 전체적으로 498 - 521 K에서 온도제어가 가능했으며 계산된 사슬성장 가능성은 저온 피셔-트롭쉬 합성에 적합한 것으로 보인다.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2012년도 제43회 하계 정기 학술대회 초록집
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• pp.368-368
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• 2012

We report solution-processed, high-performance single-crystal organic nanowire transistors fabricated from a novel indolocarbazole (IC) derivative. The direct printing process was utilized to generate single-crystal organic nanowire arrays enabling the simultaneous synthesis, alignment and patterning of nanowires using molecular ink solutions. Using this method, single-crystal organic nanowires can easily be synthesized by self-assembly and crystallization of organic molecules within the nanoscale channels of molds, and these nanowires can then be directly transferred to specific positions on substrates to generate nanowire arrays by a direct printing process. These new molecules are particularly suitable for p-channel organic field-effect transistors (OFETs) because of the high level of crystallinity usually found in IC derivatives. Selected area diffraction (SAED) and X-ray diffraction (XRD) experiments on these solution-processed nanowires showed high crystallinity. Transistors fabricated with these nanowires gave a hole mobility as high as 1.0 cm2V-1s-1 with nanowire arrays with the direct printing process.

• 센서학회지
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• 제29권2호
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• pp.133-140
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• 2020

This study proposes a method of blending visible and near infrared images to enhance edge details and local contrast. The proposed method consists of radiance map generation and color compensation. The radiance map is produced by a Laplacian pyramid and a soft mixing method based on principal component analysis. The color compensation method uses the ratio between the composed radiance map and the luminance channel of a visible image to preserve the visible image chrominance. The proposed method has better edge details compared to a conventional visible and NIR image blending method.

• 대한전기학회:학술대회논문집
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• 대한전기학회 2005년도 제36회 하계학술대회 논문집 A
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• pp.226-228
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• 2005

This paper deals with power system stabilization problem using a network control system in which the control is applied through a communication channel in feedback form. Analysis and synthesis issues are investigated by modeling the packet delivery characteristics of the network as a Bernoulli random variable, which is described by a two state Markov chain. This model assumption yields an overall system which is described by a discrete-time Markov jump linear system. These employ the norm to measure the performance of the system, and they compute the norm via a necessary and sufficient matrix inequality condition.

• 한국정밀공학회:학술대회논문집
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• 한국정밀공학회 2001년도 춘계학술대회 논문집
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• pp.723-726
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• 2001

The design of delivery system is one of the most important subject in injection molding. Delivery system is a channel to flow the polymer melt from the injection molding machine to the mold cavities and affect quality and productivity of the part. The synthesis of delivery system of injection molding has been done empirically, since it requires profound knowledge about the moldability and causal effects on the properties of the part, which are not available to designers through the current CAD systems. A knowledge-based CAD system is constructed by adding the knowledge module to an existing geometric modeler and contains knowledge to permit non-experts ad well as mold design experts to generate the acceptable geometries of gate and runner for injection molded parts.