• 전기의세계
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• 제31권3호
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• pp.204-208
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• 1982

The objective of this paper is to present a digital method for improving the lateral resolution of the B-scan images in the medical applications of ultrasound. The method is based upon a mathematical model of the lateral blurring caused by the finite beam width of the transducers. This model provides a simple method of applying a recursive scheme for image restoration with fast computation time. The point spread function (P.S.F.) can be measured by the reflective signals after scanning the small pins located along the depth of interest. From the measured P.S.F., one can compute the coefficient matrices of the inverse discrete-time dynamic state variable equation of the blurring process. Then, a recursive scheme for deblurring is applied to the recorded B-scan to improve the lateral resolution. One major advantage of the present recursive scheme over the transform method is in its applicability for the space-variant imaging, such as in the case of the rotational movement of transducer.

• Journal of Periodontal and Implant Science
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• 제41권3호
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• pp.157-163
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• 2011

Purpose: Curcumin is known to exert numerous biological effects including anti-inflammatory activity. In this study, we investigated the effects of curcumin on the production of interleukin-6 (IL-6) by murine macrophage-like RAW 264.7 cells stimulated with lipopolysaccharide (LPS) from Prevotella intermedia, a major cause of inflammatory periodontal disease, and sought to determine the underlying mechanisms of action. Methods: LPS was prepared from lyophilized P. intermedia ATCC 25611 cells by the standard hot phenol-water method. Culture supernatants were collected and assayed for IL-6. We used real-time polymerase chain reaction to detect IL-6 mRNA expression. $I{\kappa}B-{\alpha}$ degradation, nuclear translocation of NF-${\kappa}B$ subunits, and STAT1 phosphorylation were characterized via immunoblotting. DNA-binding of NF-${\kappa}B$ was also analyzed. Results: Curcumin strongly suppressed the production of IL-6 at both gene transcription and translation levels in P. intermedia LPS-activated RAW 264.7 cells. Curcumin did not inhibit the degradation of $I{\kappa}B-{\alpha}$ induced by P. intermedia LPS. Curcumin blocked NF-${\kappa}B$ signaling through the inhibition of nuclear translocation of NF-${\kappa}B$ p50 subunit. Curcumin also attenuated DNA binding activity of p50 and p65 subunits and suppressed STAT1 phosphorylation. Conclusions: Although further study is required to explore the detailed mechanism of action, curcumin may contribute to blockade of the host-destructive processes mediated by IL-6 and appears to have potential therapeutic values in the treatment of inflammatory periodontal disease.

• 정보관리학회지
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• 제40권4호
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• pp.73-94
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• 2023

본 연구는 Web of Science (WoS) 논문을 기반으로 주요 5개국의 Open Access (OA) 논문 비중과 방식을 분석하고 조절효과(Moderating Effect) 검증을 통해 OA의 피인용 유도에 차이가 나타나는지 검증하였다. 분석 결과, OA 비중은 영국이 62.7%로 가장 높았으며, 중국이 38.0%로 가장 낮게 나타났다. 또한 셀프 아카이빙과 Gold Hybrid가 OA의 주요 실천 방법 중 하나로 나타난 영미와 달리, 중국과 한국의 OA 논문은 Gold 저널 출판에 집중되어 있는 것으로 분석되었다. 두 번째, 조절효과 분석 결과, 우수 논문의 OA 출판 및 유통이 활성화된 영국, 미국, 일본의 경우 OA 비중이 높을수록 피인용량을 유도하는 효과가 커지는 것으로 나타났으나, 한국(B=-0.00003, p<0.01)과 중국(B=-0.00001, p<0.01)에서는 역의 방향성이 나타나 차이를 보였다. 더불어 대부분의 학문분야에서 OA가 피인용을 유도하였으나 공학 분야(B=-0.00002, p<0.01)에서는 역의 방향성을 보이는 것으로 분석되었다.

• 한국광학회지
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• 제23권6호
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• pp.246-250
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• 2012

We derive analytical expressions for the output spectral density and the noise power $P_{\beta}$ in noise loading analysis using Volterra kernels to characterize fiber nonlinearities. The bandwidth of the input noise source has little effect on $P_{\beta}$, but the power of the input noise source and the dispersion parameter value of the fiber have a significant effect on $P_{\beta}$. The Volterra method predicts ${\Delta}P_{\beta}[dB]$ = 30 dB/decade, which agrees very accurately over a wide range of fiber parameters compared with the numerical results by the split-step Fourier method. Therefore the Volterra method could be useful to predict the performance of a dense WDM system when we plan to upgrade fiber or increase signal power.

• 디지털융복합연구
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• 제11권1호
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• pp.361-368
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• 2013

본 연구의 목적은 악성 및 양성 여성골반 병변에서 자기공명 확산강조영상의 정량적, 정성적평가을 통하여 최적의 확산경사계수(b-values) 값을 구하고, 임상적 유용성을 알아보고자 하였다. 확산강조영상의 b-value($s/mm^2$)값을 600, 800, 1000, 1200, 1400까지 변화시키면서 얻었다. 정량적 분석결과 b-values 값 중 800에서 자궁근종의 평균 신호대 잡음비 $84.6{\pm}4.57$(p=0.024) 와 대조도대 잡음비 $50.13{\pm}5.47$(p=0.028)로 가장 높았고, 자궁경부암의 평균 신호대 잡음비 $12.0{\pm}2.04$(p=0.047)와 대조도대 잡음비 $10.6{\pm}1.24$(p=0.001)로 가장 높았으며, 이때 현성확산계수는 자궁근종 $1.19{\times}10^{-3}$(p=0.008), 자궁경부암 $0.96{\times}10^{-3}$(p=0.027) 이었다. 정성적 분석결과로서 병변의 묘출도와 명확성은 $4.02{\pm}0.18$(p=0.028), $4.39{\pm}0.25$(p=0.015)로 800에서 가장 높았다. 결론적으로 확산강조 자기공명영상은 여성골반 병변 검출에 있어서 중요한 방법이고, 최적의 b-value($s/mm^2$)값은 $800s/mm^2$ 이었으며, 정량적, 정성적 평가는 여성골반의 악성 및 양성 감별진단에 도움을 주었다.

• 한국식품과학회지
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• 제20권1호
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• pp.85-89
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• 1988

본 실험은 포장우육에서 가장 주요한 부패균의 하나인 B. thermosphacta의 생육특성을 조사하여 포장육 실험의 기초 자료를 마련하고자 실시하였으며 진공포장우육에서 B. thermosphacta와 lactic acid bacteria의 존재에 따른 B. thermosphacta의 생육 특성을 조사하였다. 통기성 포장우육에서는 높은 우육의 pH 범위에서 pH가 B. thermosphacta의 생육에 크게 영향을 미치지 않았으며 진공포장우육에서는 pH 5.5-5.6에서 pH 5.7이상에서 보다 크게 증식이 지연되었다. 포장방법에 따른 B. thermosphacta의 증식은 pH 5.7-6.0의 우육에서 100%가스포장했을 때 이들의 증식이 중지되었고, $20%CO_2$와 $80%N_2$ 혼합가스포장 했을 때 가벼운 증식억제 효과를 보였다. 또한 1 actic acid bacteria의 B. thermosphacta 증식억제 작용은 통기성 포장에서 약하게 나타났으나, 진공포장에서는 pH가 낮을수록 크게 나타났으며, pH 5.5-5.6의 우육에서 B. thermosphacta 는 거의 성장이 중지되었다.

• Journal of Gastric Cancer
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• 제22권2호
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• pp.83-93
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• 2022

Background: To analyze the short- and long-term clinical outcomes of 2 reconstruction methods after distal gastrectomy for gastric cancer. Methods: Three keywords, "gastric neoplasm," "distal gastrectomy," and "reconstruction," were used to search PubMed. We selected only randomized controlled trial that compared the anastomosis methods. A total of 11 papers and 8 studies were included in this meta-analysis. All statistical analyses were performed using the R software. Results: Among short-term clinical outcomes, a shorter operation time, reduced morbidity, and shorter hospital stay were found for Billroth type I (B-I) than for Roux-en-Y (RNY) reconstruction in the meta-analysis (P<0.001, P=0.048, P<0.001, respectively). When comparing Billroth type II (B-II) to RNY, the operation time was shorter for B-II than for RNY (P<0.019), but there were no differences in morbidity or length of hospital stay (P=0.500, P=0.259, respectively).Regarding long-term clinical outcomes related to reflux, there were significantly fewer incidents of reflux esophagitis, reflux gastritis, and bile reflux (P=0.035, P<0.001, P=0.019, respectively) for RNY than for B-I in the meta-analysis, but there was no difference between the 2 methods in residual food (P=0.545). When comparing B-II to RNY, there were significantly fewer incidents of reflux gastritis (P<0.001) for RNY than for B-II, but the amount of residual food and patient weight gain showed no difference. Conclusion: B-I had the most favorable short-term outcomes, but RNY was more advantageous for long-term outcomes than for other methods. Surgeons should be aware of the advantages and disadvantages of each type of anastomosis and select the appropriate method.

• 전자공학회논문지B
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• 제33B권11호
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• pp.72-82
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• 1996

In this paper, newly developed algorithm for enhancing images corrupted by white gaussian noise is proposed. In the method proposed here, image is subdivided into a number of subblocks, and each block is separated into cimponents corresponding to signal and noise subspaces, respectively through the signal subspace method. A clean signal is then estimated form the signal subspace by the adaptive wiener filtering. The decomposition of noisy signal into noise and signal subspaces in is implemented by eigendecomposition of covariance matrix for noisy image, and by performing blockwise KLT (karhunen loeve transformation) using eigenvector. To reduce the perceptual noise level and distortion, wiener filtering is implementd by adaptively adjusting noise level according to activity characteristics of given block. Simulation results show the effectiveness of proposed method. In particular, edge bluring effects are reduced compared to the previous methods.

• Biomolecules & Therapeutics
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• 제28권2호
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• pp.152-162
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• 2020

Cerebral ischemia exhibits a multiplicity of pathophysiological mechanisms. During ischemic stroke, the reactive oxygen species (ROS) concentration rises to a peak during reperfusion, possibly underlying neuronal death. Recombinant human erythropoietin (EPO) supplementation is one method of treating neurodegenerative disease by reducing the generation of ROS. We investigated the therapeutic effect of PEGylated EPO (P-EPO) on ischemic stroke. Mice were administered P-EPO (5,000 U/kg) via intravenous injection, and middle cerebral artery occlusion (MCAO) followed by reperfusion was performed to induce in vivo ischemic stroke. P-EPO ameliorated MCAO-induced neurological deficit and reduced behavioral disorder and the infarct area. Moreover, lipid peroxidation, expression of inflammatory proteins (cyclooxygenase-2 and inducible nitric oxide synthase), and cytokine levels in blood were reduced by the P-EPO treatment. In addition, higher activation of nuclear factor kappa B (NF-κB) was found in the brain after MCAO, but NF-κB activation was reduced in the P-EPO-injected group. Treatment with the NF-κB inhibitor PS-1145 (5 mg/kg) abolished the P-EPO-induced reduction of infarct volume, neuronal death, neuroinflammation, and oxidative stress. Moreover, P-EPO was more effective than EPO (5,000 U/kg) and similar to a tissue plasminogen activator (10 mg/kg). An in vitro study revealed that P-EPO (25, 50, and 100 U/mL) treatment protected against rotenone (100 nM)-induced neuronal loss, neuroinflammation, oxidative stress, and NF-κB activity. These results indicate that the administration of P-EPO exerted neuroprotective effects on cerebral ischemia damage through anti-oxidant and anti-inflammatory properties by inhibiting NF-κB activation.

• 대한화학회지
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• 제51권1호
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• pp.21-30
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• 2007

다중파장 분광광도법 적정을 사용하여 25 oC에서 0.1M NaNO3를 함유한 에탄올-물 이성분 혼합 용매 중에서 네 가지 수용성 비타민인 엽산(비타민 B9 또는 B10), 티아민(비타민 B1), 리보플라빈(비타민 B2) 및 피리독살(비타민 B6)의 양성자이전상수를 조사하였다. 인자분석모형으로 pH-흡광도 데이터를 적절한 질량균형방정식에 곡선맞추기 (curve fitting)하여 양성자이전 평형상수, 스펙트럼, 농도 도표와 성분 수를 계산하였다. DATAN 프로그램으로 산도상수를, SPECFIT 프로그램으로 표준편차와 부분상관계수를 계산하였다. Gran 도시에 바탕을 둔 4-파라미터 식, pH = α + SpcH + JH+[H+] + JOH-Kw/[H+]에 의거한 유리전극 보정과정을 사용하여 pH값을 농도 척도(pcH)로 읽었으며, 용매가 양성자이전상수에 미치는 영향을 고찰하였다.