• Title/Summary/Keyword: small-signal

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The Research to Correct Overestimation in TOF-MRA for Severity of Cerebrovascular Stenosis (3D-SPACE T2 기법에 의한 TOF-MRA검사 시 발생하는 혈관 내 협착 정도의 측정 오류 개선에 관한 연구)

  • Han, Yong Su;Kim, Ho Chul;Lee, Dong Young;Lee, Su Cheol;Ha, Seung Han;Kim, Min Gi
    • Journal of the Institute of Electronics and Information Engineers
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    • v.51 no.12
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    • pp.180-188
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    • 2014
  • It is very important accurate diagnosis and quick treatment in cerebrovascular disease, i.e. stenosis or occlusion that could be caused by risk factors such as poor dietary habits, insufficient exercise, and obesity. Time-of-flight magnetic resonance angiography (TOF-MRA), it is well known as diagnostic method without using contrast agent for cerebrovascular disease, is the most representative and reliable technique. Nevertheless, it still has measurement errors (also known as overestimation) for length of stenosis and area of occlusion in celebral infarction that is built by accumulation and rupture of plaques generated by hemodynamic turbulence. The purpose of this study is to show clinical trial feasibility for 3D-SPACE T2, which is improved by using signal attenuation effects of fluid velocity, in diagnosis of cerebrovascular disease. To model angiostenosis, strictures of different proportions (40%, 50%, 60%, and 70%) and virtual blood stream (normal saline) of different velocities (0.19 ml/sec, 1.5 ml/sec, 2.1 ml/sec, and 2.6 ml/sec) by using dialysis were made. Cross-examinations were performed for 3D-SPACE T2 and TOF-MRA (16 times each). The accuracy of measurement for length of stenosis was compared in all experimental conditions. 3D-SPACE 2T has superiority in terms of accuracy for measurements of the length of stenosis, compared with TOF-MRA. Also, it is robust in fast blood stream and large stenosis than TOF-MRA. 3D-SPACE 2T will be promising technique to increase diagnosis accuracy in narrow complex lesions as like two cerebral small vessels with stenosis, created by hemodynamic turbulence.

The Result of Bone Grafting for Fibrous Dysplasia (섬유성 골 이형성증에서 시행한 골 이식술의 결과 분석)

  • Jeong, Won-Ju;Kim, Tae-Seong;Cho, Hwan-Seong;Yoon, Jong-Pil;Park, Il-Hyung
    • The Journal of the Korean bone and joint tumor society
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    • v.20 no.2
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    • pp.74-79
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    • 2014
  • Purpose: Fibrous dysplasia is related to the mutation of gene encoding the alpha-subunit of a signal-transducing G-protein and has variable clinical course. Operation can be performed to prevent functional disorder or structural deformity. After curettage, autologous bone graft were used to fill the defects after curettage. The aim of this study is to compare the result of autogenous cancellous bone grafting and allogenic bone grafting for fibrous dysplasia. Materials and Methods: Among the patients who visit our hospital during the period of April, 1997 to October, 2013, we selected 34 patients who diagnosed fibrous dysplasia and visited our clinic over 1 year. There were 13 males and 21 females. Average age was 26.4 (range 2 to 57) years old. Autogenous bone graft (group I) in 5 cases, Non-autogenous bone graft (group II) in 30 cases. Iliac bone is used in all cases of autogenous bone graft. There were no significant difference in age, follow-up period, preoperational laboratory finding between two groups. Radiographic image was done to evaluate the recurrence of fibrous dysplasia or secondary degeneration. Results: There were four cases in recurrence (group I: 1 case, group II: 3 cases, p=0.554). In all recurrent cases, reoperations were done using curettage and autogenous iliac bone graft. There was no re-recurrence after reoperation. One case of secondary aneurysmal bone cyst was confirmed (group II) and 1 cases of pathologic fractures had developed (group I: 0 case, group II: 1 cases, p=0.559). No malignant change occurred. Conclusion: There were no significant difference between autogenous bone graft group and non-autogenous bone graft group. Our result suggested that autogenous bone graft seems to be good method to treat fibrous dysplasia, in the case of small volume of tumor lesion or non-weight bearing portion.

MR Imaging Findings of Uterine Cervical Adenocarcinoma (자궁경부 선암종의 자기공명영상 소견)

  • 김종철
    • Investigative Magnetic Resonance Imaging
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    • v.2 no.1
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    • pp.113-119
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    • 1998
  • Purpose : Because adenocarcinomas of the uterine cervix have lower 5-year survival rate than squamous cell carcinomas due to early lymph node metastasis and local extension, scrutiny of lymph node metastasis and local extension by radiologic examination is necessary in case of clinically diagnosed or suspected adenocarcinomas. The purpose of this study is to evaluate whether there are specific findings of these tumors, compared with squamous cell carcinomas, through the analysis of magnetic resonance (MR) imaging findings. Materials and Methods : Of 21 pathologically proven cervical adenocarcinomas, MR imaging findings of 18 tumors (histologic staging : two Ib, four IIa, two IIb, one IIIa, and one IIIb) were retrospectively analyzed and compared with those of 40 wquamous cell carcinoma in consecutive patients as a control group. T1-wetighted and fast spin echo T2-weighted images were obtained on the axial and sagittal planes, using a 1.5-T MR scanner. The largest diameter, location, signal intensity and degree of contrast enhancement contour, shape and longitudinal extent of the tumor and associated findings on MR image were analyzed. Results : The largest diameters of cervical adenocarcinomas ranged from 0.8 to 4.1 cm(mean, 2.2 cm). Of 18 adenocarcinomas, nine were of endocervical type. All adenocarcinomas were isointense to surrounding cervical stroma on T1-weighted images and hyperintense(homogeneous in ten, inhomogeneous in eight) on fast spin echo T2-weighted images. Adenocarcinomas enhanced on contrast study in all patients (homogeneous in six, inhomogeneous in 12 with hyperintese enhnacing rim in two). Eight adenocarcinomas had smooth contours and ten had irregular ones. The shape of adenocarcinoma was irregular in eight patients, barrel shape in six, papillary/polypod in three, and nodular in one. All adenocarcinomas involved lower half of the uterine cervix and six tumors extended up to the upper half. Pelvic lymph nodes of more than 1.5cm in diameter in two adenocarcinomas pateints and no detectable small pelvic lymph nodes on MR imaging in one patient were pathologically positive. Hydrometra was associated in two adenocarcinomas patients, and hematometra in one patient. Compared with squamous cell carcinomas, more frequent MR findings of endocervical type and barrel shape in cervical adenocarcinomas were statistically significant. Conclusion : Cervical adenocarcinomas had more frequent MR findings of endocervical type and barrel shape, compared with wquamous cell carcinomas. Adenocarcinoma of the uterine cervix may be suspected on MR imaging, when a cervical carcinoma is of barrel shape along the endocervical canal and tends to involve lymth nodes in earlier stages.

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Resolution of Shallow Marine Subsuface Structure Image Associated with Acquisition Parameters of High-resolution Multi-channel Seismic Data (고해상 다중채널 탄성파탐사 자료취득변수에 따른 천부 해저지층영상의 해상도)

  • Lee Ho-Young;Koo Nam-Hyung;Park Keun-Pil;Yoo Dong-Geun;Kang Dong-Hyo;Kim Young-Gun;Seo Gab-Seok;Hwang Kyu-Duk;Kim Jong-Chon;Kim Ji-Soo
    • Geophysics and Geophysical Exploration
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    • v.6 no.3
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    • pp.126-133
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    • 2003
  • High-resolution shallow marine seismic surveys have been carried out for the resources exploration, engineering applications and Quaternary mapping. To improve the resolution of subsurface structure image, multichannel digital technique has been applied. The quality of the image depends on the vertical and horizontal resolution and signal to noise (S/N) ratio which are associated with the data acquisition parameters such as sample interval, common midpoint (CMP) interval and CMP fold. To understand the effect of the acquisition parameters, a test survey was carried out off Yeosu and the acquired data were analyzed. A 30 $in^3$ small air gun was used as a seismic source and 8 channel streamer cable with a 5 m group interval was used as a receiver. The data were digitally recorded with a shot interval of 2 s and sample interval of 0.1 ms. The acquired data were resampled with various sample intervals, CMP intervals and CMP folds. The resampled data were processed, plotted as seismic sections and compared each other. The analysis results show that thin bed structure with ${\~}1m$ thickness and ${\~}6^{\circ}$ slope can be imaged with good resolution and continuity and low noise using the acquisition parameters with a sample interval shorter than 0.2 ms, CMP interval shorter than 2.5 m and CMP fold more than 4. Because seismic resolution is associated with the acquisition parameters, the quality of the subsurface structure can be imaged successfully using suitable and optimum acquisition parameters.

Availability Assessment of Single Frequency Multi-GNSS Real Time Positioning with the RTCM-State Space Representation Parameters (RTCM-SSR 보정요소 기반 1주파 Multi-GNSS 실시간 측위의 효용성 평가)

  • Lee, Yong-Chang;Oh, Seong-Jong
    • Journal of Cadastre & Land InformatiX
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    • v.50 no.1
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    • pp.107-123
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    • 2020
  • With stabilization of the recent multi-GNSS infrastructure, and as multi-GNSS has been proven to be effective in improving the accuracy of the positioning performance in various industrial sectors. In this study, in view that SF(Single frequency) GNSS receivers are widely used due to the low costs, evaluate effectiveness of SF Real Time Point Positioning(SF-RT-PP) based on four multi-GNSS surveying methods with RTCM-SSR correction streams in static and kinematic modes, and also derive response challenges. Results of applying SSR correction streams, CNES presented good results compared to other SSR streams in 2D coordinate. Looking at the results of the SF-RT-PP surveying using SF signals from multi-GNSS, were able to identify the common cause of large deviations in the altitude components, as well as confirm the importance of signal bias correction according to combinations of different types of satellite signals and ionospheric delay compensation algorithm using undifferenced and uncombined observations. In addition, confirmed that the improvement of the infrastructure of Multi-GNSS allows SF-RT-SPP surveying with only one of the four GNSS satellites. In particular, in the case of code-based SF-RT-SPP measurements using SF signals from GPS satellites only, the difference in the application effect between broadcast ephemeris and SSR correction for satellite orbits/clocks was small, but in the case of ionospheric delay compensation, the use of SBAS correction information provided more than twice the accuracy compared to result of the Klobuchar model. With GPS and GLONASS, both the BDS and GALILEO constellations will be fully deployed in the end of 2020, and the greater benefits from the multi-GNSS integration can be expected. Specially, If RT-ionospheric correction services reflecting regional characteristics and SSR correction information reflecting atmospheric characteristics are carried out in real-time, expected that the utilization of SF-RT-PPP survey technology by multi-GNSS and various demands will be created in various industrial sectors.

Vibrio Vulnificus Induces the Inflammation of Mouse Ileal Epithelium: Involvement of Protein Kinase C and Nuclear Factor-Kappa B (회장 상피세포에서 비브리오균(Vibrio vulnificus)의 염증 유도 기작 연구: protein kinase C와 nuclear factor kappa-B의 관련성)

  • Han, Gi Yeon;Jung, Young Hyun;Jang, Kyung Ku;Choi, Sang Ho;Lee, Sei-Jung
    • Journal of Life Science
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    • v.24 no.6
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    • pp.664-670
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    • 2014
  • In the present study, we investigate the role of V. vulnificus in promoting the inflammation of mouse ileal ephitelium and its related signaling pathways. ICR mice were infected orally with V. vulnificus ($1{\times}10^9CFU$) for 16 h as a representative model of food-borne infection. To find the major portal of entry of V. vulnificus in mouse intestine, we have measured the levels of bacterial colonization in small intestine, colon, spleen, and liver. V. vulnificus appeared to colonize in intestine and colon in the order of ileum >> jejunum> colon, but lack in the duodenum, spleen, and liver. V. vulnificus in ileum caused severe necrotizing enteritis and showed shortened villi heights accompanied by an expanded width and inflammation, compared with the control mice. V. vulnificus induced ileal epithelium inflammation by activating phosphorylation of PKC and membrane translocation of $PKC{\alpha}$. V. vulnificus induced the phosphorylation of ERK and JNK, but did not affect p38 MAPK phosphorylation. Notably, V. vulnificus stimulated the I-${\kappa}B$-dependent phosphorylation of NF-${\kappa}B$ in mouse ileal epithelium. Finally, the ileal infection of V. vulnificus resulted in a significant increase in expression of proinflammatory cytokines and Toll-like receptors, respectively, compared to the control. Collectively, our results indicate that V. vulnificus induces ileal epithelium inflammation by increasing NF-${\kappa}B$ phosphorylation via activation of PKC, ERK, and JNK, which is critical for host defense mechanism in food-borne infection by V. vulnificus.

The Study on the Factors for Detection of Renal Stone on Ultrasound (초음파 검사에서 신장 결석의 검출 요인에 관한 연구)

  • Sim, Hyun-Sun;Jung, Hong-Ryang;Lim, Cheong-Hwan
    • Journal of radiological science and technology
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    • v.29 no.1
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    • pp.1-6
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    • 2006
  • Purpose: Renal stones are common and typically arise within the collecting system. The renal sinus are contains the collection system, the renal vessels, lymphatcs, fat, and fibrous tissue. Because of the compression of all the large echoes in signal processing, the echo from the renal stone generally cannot be distinguished from large echoes emanating from normal structures of the renal sinus. Use of ultrasonography has been difficult for detecting small renal stone without posterior shadowing and chemical composition of stone. The aim of study was measuring for posterior acoustic shadowing to a stone for various scan parameter and it examines a help in renal stone diagnosis. Material & Methods: The stone was place on sponge examined in a water bath with a 3.5MHz or 7.5MHz transducer(LOGIQ 400, USA). First, tested a variety of gain. Second, tested a variety of dynamic range. Third, tested a variety of focal zone. Fourth, measuring of the echo level for low and high frequency for depth. Results: 1) Average echo level was 98 for low total gain(10 dB) and was 142 for high total gain(40 dB). Posterior acoustic shadowing of renal stone was clear for low gain. 2) Average echo level was 129 for low dynamic range(42 dB) and was 101 for high dynamic range(72 dB). Posterior acoustic shadowing of renal stone was clear for high dynamic range. 3) When stone is in focal zone of transducer, definite posterior acoustic shadow is identified. 4) Stone was clear appeared for high frequency(7.5 MHz) than low frequency(3.5 MHz) and it is not distorted. Conclusion: The demonstration of an posterior acoustic shadow of renal stone dependents on several technical factors such as gain, dynamic range, focus, and frequency. This various factors are a help in renal stone diagnosis.

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Molecular Miology of the Poliovirus (폴리오바이러스의 분자생물학)

  • 최원상
    • Journal of Life Science
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    • v.7 no.4
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    • pp.392-401
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    • 1997
  • The poliovirus is a small, and non-enveloped virus. The RNA genome of poliovirus is continuous, linear, and has a single open reading frame. This polyprotein precursor is cleaved proteolytically to yield mature products. Most of the cleavages occur by viral protease. The mature proteins derived from the P1 polyprotein precursor are the structural components of the viral capsid. The initial cleavage by 2A protease is indirectly involved in the cleavage of a cellular protein p220, a subunit of the eukaryotic translation initiation factor 4F. This cleavage leads to the shut-off of cap-dependent host cell translation, and allows poliovirus to utilize the host cell machinery exclusively for translation its own RNA, which is initiated by internal ribosome entry via a cap-independent mechanism. The functional role of the 2B, 2C and 2BC proteins are not much known. 2B, 2C, 2BC and 3CD proteins are involved in the replication complex of virus induced vesicles. All newly synthesized viral RNAs are linked with VPg. VPg is a 22 amino acid polypeptide which is derived from 3AB. The 3C and 3CD are protease and process most of the cleavage sites of the polyprotein precursor. The 3C protein is also involved in inhibition of RNA polymerase II and III mediated transcription by converting host transcription factor to an inactive form. The 3D is the RNA dependent RNA polymerase. It is known that poliovirus replication follows the general pattern of positive strand RNA virus. Plus strand RNA is transcribed into complementary minus strand RNA that, in turn, is transcribed for the synthesis of plus strand RNA is transcribed into complementary minus strand RNA that, in turn, is transcribed for the synthesis of plus strand RNA strands. Poliovirus RNA synthesis occurs in a membranous environment but how the template RNA and proteins required for RNA replication assemble in the membrane is not much known. The RNA requirements for the encapsidation of the poliovirus genome (packaging signal) are totally unknown. The poliovirus infection cycle lasts approximately 6 hours.

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A Formulated Korean Red Ginseng Extract Inhibited Nitric Oxide Production through Akt- and Mitogen Activated Protein Kinase-dependent Heme Oxygenase-1 Upregulation in Lipoteichoic Acid-stimulated Microglial Cells (홍삼추출액은 lipoteichoic acid로 자극된 소교세포에서 Akt 및 MAPK 의존적으로 heme oxygenase-1 발현을 유도함으로써 NO 생성을 억제함)

  • Shin, Ji Eun;Lee, Kyungmin;Kim, Ji-Hee;Madhi, Iskander;Kim, YoungHee
    • Journal of Life Science
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    • v.29 no.4
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    • pp.402-409
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    • 2019
  • Korean red ginseng made from steaming and drying fresh ginseng has long been used as a traditional herbal medicine due to its effects on the immune, endocrine, and central nerve systems and its anti-inflammatory activity. In this study, we investigated the molecular mechanism responsible for the anti-inflammatory effects of a formulated Korean red ginseng extract (RGE) in response to lipoteichoic acid (LTA), a cell wall component of gram-positive bacteria. RGE inhibited LTA-induced nitric oxide (NO) secretion and inducible nitric oxide synthase (iNOS) expression in BV-2 microglial cells, without affecting cell viability. RGE also inhibited nuclear translocation of nuclear factor kappa B ($NF-{\kappa}B$) p65 and degradation of $I{\kappa}B-{\alpha}$. In addition, RGE increased the expression of heme oxygenase-1 (HO-1) in a dose-dependent manner, and the inhibitory effect of RGE on iNOS expression was abrogated by small interfering RNA-mediated knockdown of HO-1. Moreover, RGE induced nuclear translocation of nuclear factor E2-related factor 2 (Nrf2), a transcription factor that regulates HO-1 expression. Furthermore, the phosphoinositide-3-kinase (PI-3K) inhibitor and mitogen-activated protein kinase (MAPK) inhibitors suppressed RGE-mediated expression of HO-1, and RGE enhanced the phosphorylation of Akt, extracellular signal-regulated kinases (ERKs), p38, and c-JUN N-terminal kinases (JNKs). These results suggested that RGE suppressed the production of NO, a proinflammatory mediator, by inducing HO-1 expression via PI-3K/Akt- and MAPK-dependent signaling in LTA-stimulated microglia. The findings indicate that RGE could be used for the treatment of neuroinflammation induced by grampositive bacteria and that it may have therapeutic potential for various neuroinflammation-associated disorders.

INTENSIVE MONITORING SURVEY OF NEARBY GALAXIES (IMSNG)

  • Im, Myungshin;Choi, Changsu;Hwang, Sungyong;Lim, Gu;Kim, Joonho;Kim, Sophia;Paek, Gregory S.H.;Lee, Sang-Yun;Yoon, Sung-Chul;Jung, Hyunjin;Sung, Hyun-Il;Jeon, Yeong-beom;Ehgamberdiev, Shuhrat;Burhonov, Otabek;Milzaqulov, Davron;Parmonov, Omon;Lee, Sang Gak;Kang, Wonseok;Kim, Taewoo;Kwon, Sun-gill;Pak, Soojong;Ji, Tae-Geun;Lee, Hye-In;Park, Woojin;Ahn, Hojae;Byeon, Seoyeon;Han, Jimin;Gibson, Coyne;Wheeler, J. Craig;Kuehne, John;Johns-Krull, Chris;Marshall, Jennifer;Hyun, Minhee;Lee, Seong-Kook J.;Kim, Yongjung;Yoon, Yongmin;Paek, Insu;Shin, Suhyun;Taak, Yoon Chan;Kang, Juhyung;Choi, Seoyeon;Jeong, Mankeun;Jung, Moo-Keon;Kim, Hwara;Kim, Jisu;Lee, Dayae;Park, Bomi;Park, Keunwoo;O, Seong A
    • Journal of The Korean Astronomical Society
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    • v.52 no.1
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    • pp.11-21
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    • 2019
  • Intensive Monitoring Survey of Nearby Galaxies (IMSNG) is a high cadence observation program monitoring nearby galaxies with high probabilities of hosting supernovae (SNe). IMSNG aims to constrain the SN explosion mechanism by inferring sizes of SN progenitor systems through the detection of the shock-heated emission that lasts less than a few days after the SN explosion. To catch the signal, IMSNG utilizes a network of 0.5-m to 1-m class telescopes around the world and monitors the images of 60 nearby galaxies at distances D < 50 Mpc to a cadence as short as a few hours. The target galaxies are bright in near-ultraviolet (NUV) with $M_{NUV}$ < -18.4 AB mag and have high probabilities of hosting SNe ($0.06SN\;yr^{-1}$ per galaxy). With this strategy, we expect to detect the early light curves of 3.4 SNe per year to a depth of R ~ 19.5 mag, enabling us to detect the shock-heated emission from a progenitor star with a radius as small as $0.1R_{\odot}$. The accumulated data will be also useful for studying faint features around the target galaxies and other science projects. So far, 18 SNe have occurred in our target fields (16 in IMSNG galaxies) over 5 years, confirming our SN rate estimate of $0.06SN\;yr^{-1}$ per galaxy.