• Journal of the Optical Society of Korea
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• 제2권1호
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• pp.9-12
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• 1998

Rational harmonic mode-locking of an Er-doped fiber ring laser has been successfully demonstrated up to the 16-th harmonic, of the RF frequency applied to the electro-optic modulator. This is the highest harmonic reported so far to our knowledge.

• 대한약침학회지
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• 제22권1호
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• pp.7-15
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• 2019

Portulaca oleracea L. (PO) or Purslane is an annual grassy plant that is distributed in many parts of the world, especially the tropical and subtropical areas. PO has some pharmacological properties such as analgesic, antibacterial, skeletal muscle-relaxant, wound-healing, anti- inflammatory and a radical scavenger. This review article is focused on the anti-inflammatory, immuno-modulatory, anti-oxidant and anti-tumor activities of the PO. Anti-inflammatory, immuno-modulatory, anti-oxidant and Anti-tumor effects of PO were searched using various databases until the end of August 2018. The online literature was searched using PubMed, Science Direct, Scopus, Google Scholar and Web of Science. Our review showed that PO exerts its effects through anti-inflammatory properties and balancing the adaptive and innate immune system depending on situations. PO acts as immune-modulator and anti-oxidant agent in both inflammatory states by the dominance of Th2 response such as asthma, cancer and atopic dermatitis and evoked Th1 disorders including hepatitis and multiple sclerosis.

• 한국응용약물학회:학술대회논문집
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• 한국응용약물학회 1994년도 춘계학술대회 and 제3회 신약개발 연구발표회
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• pp.287-287
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• 1994

In the present study, it was aimed to asses the possibility that calcitonin gene-related peptide (CGRP) released in response to transient hypotension may contribute to the reflex autoregulation of cerebral blood flow as a putative modulator. Changes in pial arterial diameter (mean, 33.0 ${\pm}$ 1.1 $\mu\textrm{m}$) with changes in systemic arterial blood pressure (mean, 101.9 ${\pm}$ 2.7 mmHg) were observed directly through a closed cranial window in anesthetized normotensive rats. Image of the pial vessels was captured with a stereoscope connected to a CCD video camera and the diameter was measured with a microscaler. In the capsaicin-treated rats (one day prior to experiment, 50 nmol capsaicin injected intracisternally), both vasodilater and vasoconstrictor responses evoked by a transient hypotension and the reverse of blood pressure were markedly attenuated or almost abolished. When changes in pial arterial diameter were plotted as a function of changes in blood pressure, the slopes of both regression lines (for vasodilators and vasoconstrictors ) were markedly reduced. Similar reductions were evidenced under treatment wi th the CGRP antibody serum (1:1,000) and following CGRP receptor desensitization. However, the autoregulatory mechanics were neither affected by treatment wi th spantide (1 ${\mu}$M), substance P antagonist, nor by substance P receptor desensitization. Suffusion wi th mock cerebrospinal fluid containing CGRP and cromakalim caused a vasodilatation in a concentration-dependent manner, respectively and their effects were antagonized by glibenclamide. Substance P produced a vasodilatation, which was, however, little affected by glibenclamide. These observations indicate that the CGRP released from the perivascular sensory fibers in response to a hypotension is implicated in the modulation of the autoregulation of cerebral blood flow.

• JSTS:Journal of Semiconductor Technology and Science
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• 제17권3호
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• pp.438-445
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• 2017

This paper presents a low-power high-resolution band-pass ${\Sigma}{\Delta}$ ADC for accelerometer applications. The proposed band-pass ${\Sigma}{\Delta}$ ADC consists of a high-performance 6-th order feed-forward ${\Sigma}{\Delta}$ modulator with 1-bit quantization and a low-power, area-efficient digital filter. The ADC is fabricated in 180 nm 1P6M mixed-signal CMOS process with a die area of $5mm^2$. This high-resolution ADC got 90 dB peak signal to noise plus distortion ratio (SNDR) and 96 dB dynamic range (DR) over 4 kHz bandwidth, while the intermediate frequency (IF) is shifting from 100 KHz to 200 KHz. The power dissipation of the chip is 5.6 mW under 1.8 V (digital)/3.3 V (analog) power supply.

• ETRI Journal
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• 제46권2호
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• pp.194-204
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• 2024

A new method is proposed to generate a 32-tupling frequency millimeter wave (MMW) with eight Mach-Zehnder modulators (MZMs) connected in parallel. Theoretical analyses and simulation experiments are conducted. The optical sideband suppression ratio (OSSR) of the obtained ±16th order optical sidebands are 61.54 dB and 61.42 dB, and the radio frequency spurious suppression ratios (RFSSRs) of the generated 32-tupling frequency MMW are 55.52 dB and 55.27 dB based on the theoretical analysis and simulation experiments, respectively; these outcomes verified the feasibility of the new method. The main parameters used to affect the stability of the generated signal are the modulation index and extinction ratio of MZM. Their effects on the OSSR and RFSSR of the generated signals are investigated when they deviate from their designed values. Compared with the other proposed methods for the generation of 32-tupling frequency MMW by MZM, our method has the best spectral purity and stability, and it is expected to have important MMW over fiber applications.

• Journal of Ginseng Research
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• 제47권2호
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• pp.337-346
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• 2023

Background: Ginsenoside Rb2, a major active component of Panax ginseng, has various physiological activities, including anticancer and anti-inflammatory effects. However, the mechanisms underlying the rejuvenation effect of Rb2 in human skin cells have not been elucidated. Methods: We performed a senescence-associated β-galactosidase staining assay to confirm cellular senescence in human dermal fibroblasts (HDFs). The regulatory effects of Rb2 on autophagy were evaluated by analyzing the expression of autophagy marker proteins, such as microtubule-associated protein 1A/1B-light chain (LC) 3 and p62, using immunoblotting. Autophagosome and autolysosome formation was monitored using transmission electron microscopy. Autophagic flux was analyzed using tandem-labeled GFP-RFP-LC3, and lysosomal function was assessed with Lysotracker. We performed RNA sequencing to identify potential target genes related to HDF rejuvenation mediated by Rb2. To verify the functions of the target genes, we silenced them using shRNAs. Results: Rb2 decreased β-galactosidase activity and altered the expression of cell cycle regulatory proteins in senescent HDFs. Rb2 markedly induced the conversion of LC3-I to LC3-II and LC3 puncta. Moreover, Rb2 increased lysosomal function and red puncta in tandem-labeled GFP-RFP-LC3, which indicate that Rb2 promoted autophagic flux. RNA sequencing data showed that the expression of DNA damage-regulated autophagy modulator 2 (DRAM2) was induced by Rb2. In autophagy signaling, Rb2 activated the AMPK-ULK1 pathway and inactivated mTOR. DRAM2 knockdown inhibited autophagy and Rb2-restored cellular senescence. Conclusion: Rb2 reverses cellular senescence by activating autophagy via the AMPK-mTOR pathway and induction of DRAM2, suggesting that Rb2 might have potential value as an antiaging agent.

• 한국인터넷방송통신학회논문지
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• 제8권4호
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• pp.53-58
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• 2008

본 논문은 고 해상도 및 저 전력을 가지는 시그마-델타 D/A(Digital-to-Analog) 컨버터를 구현하였다. A/D 컨버터의 출력을 채널당 1비트씩 입력 받아 LJ, RJ, I2S 모드와 비트 모드에 따라서 입력 데이터를 재구성한다. D/A 컨버터는 HBF(Half Band Filter)와 Hold, 5차 CIFB Sigma-Delta 변조기를 통과하여 원래의 아날로그 신호로 복원한다. 면적과 전력, 성능을 고려하여 곱셈 연산 대신 덧셈 연산을 반복 사용하였다. 또한, 비슷한 구조의 HBF 3개를 하나의 블록으로 구성하였고, sinc 필터 대신에 샘플-홀드 블록을 사용하여, 면적을 감소시키는 간략한 D/A 구조를 제안하였다. 블록안의 각 필터들은 매트랩 툴을 이용하여 특성을 평가하였다. 전체 블록은 Top-down 설계 방식을 사용하여, Verilog 언어로 설계하였다. 설계된 블록은 Samsung 0.35um CMOS 표준 셀 라이브러리를 사용해 칩으로 제작되었다. 칩의 면적은 1500 * 1500um 이다.

• 한국광학회지
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• 제10권2호
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• pp.146-151
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• 1999

고반복률의 안정된 솔리톤 펄스열 출력을 얻기 위해 재생형 위상 변조에 의한 고차 조화 모드록킹 방식을‘8’구조 광섬유 레이저에 적용하고 실험하였다. 레이저 펄스 출력의 종모드간 맥놀이 스펙트럼으로부터 모드록킹 기본 주파수의 96차 고조파인 400 MHz 성분을 추출하고. 이를 증폭하여 공진기 내의 위상 변조기를 구동함으로써 변조기의 변조 신호에 따라 등간격으로 정렬된 솔리톤 펄스열 출력을 얻을 수 있었다. 이때 솔리톤 펄스의 반치폭 930 fs, 반치 파장선폭은 3.1 nm 였으며, 펄스폭과 주파수 대역폭의 곱이 0.359로써 변환한계에 가까운 솔리톤 펄스임을 알 수 있었다. 변조 주파수가 레이저의 종모드간 주파수 차이와 언제나 정확히 일치하므로 능동형 모드록킹에서 흔히 요구되는 공진기 길이의 조절없이도 안정적인 고차 조화 모드록킹이 가능하였다.

• 동국한의학연구소논문집
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• 제9권
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• pp.51-71
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• 2000

본 실험은 월국환합보중익기탕(越鞠丸合補中益氣湯)의 항스트레스효과를 조사하기 위하여 시행되었다. 월국환합보중익기탕(越鞠丸合補中益氣湯)이 전기자극으로 스트레스 상황을 유발시킨 mouse에게 끼친 B 임파구 면역계 변화를 mouse 혈청의 면양적혈구(綿羊赤血球)에 대한 적혈구 응집소가와 비장세포에서 B 세포 및 T 세포가 차지하는 백분율의 변화를 통하여 측정하였으며 이를 대조군과 비교 분석하였다. 혈청 항체가의 측정에서 스트레스 자극하에서 월국환합보중익기탕(越鞠丸合補中益氣湯)을 투여받은 그룹에서 약제를 투여받지 않은 그룹에 비하여 유의성 있는 차이를 보여(p<0.01) 면역 기능을 정상군의 수준으로 유지하는 결과를 얻었다. T 세포와 B 세포의 백분율의 측정에서도 스트레스 자극하에서 월국환합보중익기탕(越鞠丸合補中益氣湯)을 투여 받은 그룹에서 약제를 투여 받지 않은 그룹에 비하여 유의성 있는 차이를 보여(p<0.01) 면역 기능을 정상군의 수준으로 유지하는 결과를 얻었다. 실험결과들로 보아 월국환합보중익기탕(越鞠丸合補中益氣湯)이 체액성 면역 반응과 비장 내 면역 세포의 백분율을 정상의 수준으로 유지하는 효과를 보여 면역 기능의 이상에 응용할 수 있는 가능성을 제시한다고 사료된다.

• Journal of Acupuncture Research
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• 제17권2호
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• pp.187-208
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• 2000

By the activation of ovary hormone, many morphological changes occur in the epithelial cell lines and muscle cells in rat uterus. These two cells in uterus are important to the implantation of embryo, maintaining pregnancy and starting parturition. One important change associated with the morphological change of these two cells in uterus is the change on prostaglandin(PG) metabolism. Its presence and synthesis in endometriurn and myometrium in uterus affects estrous cycle and the start of embryo implantation in uterus. It also performs as an important modulator in parturition. So the abnormally weak expression of PG causes difficulty during labor and over-expression causes pre-term labor. PG biosynthesis starts from either free or liberated arachidonic acids from membrane phospholipid by phospholipase. Such arachidonic acids are converted into PG catalyzed by Cyclooxygenase. Under normal physiological condition, Cyclooxygenase-1(COX-1) having 602 units of amino acids controls the synthesis of PG. It acts as a local hormone regulating vasomodulation of blood flow, flexible muscle movement, increasing the blood permeability and contributing the protective role in preserving integrity of the stomach lining and Cyclooxygenase-2 (COX-2) is induced by the inflammation, pregnancy and increased its expression until parturition. Lipid metabolite like PG is located in uterine and expression of COX-2 increased with pregnancy. Increased expression of COX proteins in epithelial cells and myometrial cells are told to increase the muscle contractility in uterus but decreased right after the labor in rat. It is a good sign indicating that COX proteins are deeply related to the start of labor. Currently, Several studies report the use of PG and COX-2 inhibitor as medication for controlled abortion or to prevent pre-term labor but they entail various side-effects. Our study proposed to suggest use of acupuncture as an another mediator to control abortion or pre-term labor without causing unnecessary side-effects by those medicines. Two acupuncture sites, LI-4 & SP-6 were selected due to their known efficacy. From the immunohistochemical staining of COX-2, normal expression of COX-2 protein in nonpregnant SD rat's uterus revealed that COX-2 protein was primarily detected in the lumina epithelial lining and in the epithelial cell lining contacting the stromal cells. High resolution optical microscopic scanning revealed distinguishable staining in the myometrial mucosa. LI-4 acupuncture administered nonpregnant rat's uterus showed strong expression for COX-2 in endometrium contacted with lumina epithelial lining of rat uterus and in myometrial mucosa. Stromal cells showed more staining than untreated nonpregnant rat's uterus and stronger staining in stromal cells contacting myometrial layer compared to untreated nonpregnant rat's uterus. SP-6 acupuncture administered nonpregnant rat's uterus showed weak expression for COX-2 in myometrial layers and stromal cells but no staining was visible in lumina epitheliai and glandular epithelial cells. Few stromal cells and myometrial mucosa were positively stained for COX-2. Pregnant SD rat's uterus was also immunostained for COX-2 expression after 18 days of pregnancy. Unlike to untreated nonpregnant rat's uterus, luminal epithelial cells were not positively stained for COX-2 but stronger staining for COX-2 was revealed in stromal cells. LI-4 acupunctured SD rat's uterus had very strong expression of COX-2 in luminal epithelial lining. Few stromal cells showed stronger positive COX-2 staining and myometrial layers also showed more expression than untreated pregnant rat. SP-6 acupuncture administered pregnant SD rat's uterus showed positive expression of COX-2 in epithelial cells of luminal mucosa layer but weaker than that of LI-4 acupuncture treatment's case. However, strong positive staining was revealed in stromal mucosa and myometrial layers. Virgin SD rat's uterus motility index during LI-4 acupuncture was 66.52 % (Prob〉T = 0.0197) compared to its motility before the acupuncture treatment but the motility index was slighdy elevated up to 79.58 % (Prob〉T = 0.1175) after the acupuncture. During the SP-6 acupuncture treatment for 30 minutes, uterus motility index was 90.52 % (Prob〉T = 0.1832) showing lesser decrement but consequently reached similar motility index decreasal to 79.95 % (Prob〉T = 0.0215) after the acupuncture treatment as LI-4 showed. LI-4 acupuncture tend to be a quick treatment to reducing the uterus motility in a virgin rat but eventually both two acupuncture administration created very similar reduction of uterus motility seeing the index after the both acupunctures. The uterus movement monitored during the LI-4 acupuncture administered for 30 minutes, Pregnant SD rat showed decreased motility down to 77.90 % (Prob〉 T = 0.0076) compared to uterus motility before the acupuncture and it continuously decreased down to 71.81 %(Prob〉T = 0.0214) after the removal of needle. The statistical analysis using paired t-test showed significance difference for both two motility indexs at =0.05. SP-6 acupuncture administered to pregnant SD rat also had similar pattern of decreasing uterus motility index down to 74.70 % (Prob〉T = 0.1730) during the initial 30 minutes acupuncture administration and it was continuously lowered to 71.52 % (Prob〉T = 0.0155) after the acupuncture. The paired t-test resuit for SP-6 suggest prompt response of uterus motility index to the SP-6 acupuncture treatment but consequently reached same level of inducing the motility reduction as LI-4 at =0.05 level.