• The Korean Journal of Physiology and Pharmacology
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• 제9권5호
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• pp.255-262
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• 2005

Striatum is involved in the control of movement and habitual memory. It receives glutamatergic input from wide area of the cerebral cortex as well as an extensive serotonergic (5-hydroxytryptamine, 5-HT) input from the raphe nuclei. In our study, the effects of 5-HT on synaptic transmission were studied in the rat corticostriatal brain slice using in vitro whole-cell recording technique. 5-HT inhibited the amplitude as well as frequency of spontaneous excitatory postsynaptic currents (sEPSC) significantly, and neither ${\gamma}-aminobutyric$ acid (GABA)A receptor antagonist bicuculline (BIC), nor $N-methyl-_{D}-aspartate$ (NMDA) receptor antagonist, $_{DL}-2-amino-5-phosphonovaleric$ acid (AP-V) could block the effect of 5-HT. In the presence non-NMDA receptor antagonist, 2,3-dioxo-6-nitro-1,2,3,4-tetrahydrobenxo[f] quinoxaline-7-sulfonamide (NBQX), the inhibitory effect of 5-HT was blocked. We also figured out that 5-HT change the channel kinetics of the sEPSC. There was a significant increase in the rise time during the 5-HT application. Our results suggest that 5-HT has an effect on both pre- and postsynaptic site with decreasing neurotransmitter release probability of glutamate and decreasing the sensitivity to glutamate by increasing the rise time of non-NMDA receptor mediated synaptic transmission in the corticostriatal synapses.

• 대한전자공학회논문지
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• 제21권6호
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• pp.27-33
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• 1984

본 논문은 TDM 전자교환기의 국간신호 장비인 CCITT R2-MF 수신기(32CH용)의 디지탈 하드웨어 실현에 관한 실험적인 연구이다. MF 검출을 위한 DSP(digital signal Processing)방법은 여러 가지가 있지만 본 수신장치의 요구조건은 특정 주파수의 예민한 주파수 응답 특성과 그의 유무 판별이 필요하므로 DFT(discrete Fourier transform)에 의한 방법이 가장 효율적이다 이의 실현은 실 시간 처리를 위해 "bit-slice micro-processor"인 Am2900 series를 사용, micro-programming 기법을 도입하여 고속처리를 하였다. 그리고 전 시스템 제어를 위하여 Z-80A processor를 사용, 하드웨어 및 소프트웨어의 융통성을 최대한 높임으로서 TDM 전자교환기의 국간 신호장치로서의 활용 가능성을 확인하였다.

• 대한의생명과학회지
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• 제25권1호
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• pp.99-106
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• 2019

Amyloid positron emission tomography (PET) allows early and accurate diagnosis in suspected cases of Alzheimer's disease (AD) and contributes to future treatment plans. In the present study, a method of implementing a diagnostic system to distinguish ${\beta}$-Amyloid ($A{\beta}$) positive from $A{\beta}$ negative with objectiveness and accuracy was proposed using a machine learning approach, such as the Principal Component Analysis (PCA) and Support Vector Machine (SVM). $^{18}F$-Florbetaben (FBB) brain PET images were arranged in control and patients (total n = 176) with mild cognitive impairment and AD. An SVM was used to classify the slices of registered PET image using PET template, and a system was created to diagnose patients comprehensively from the output of the trained model. To compare the per-slice classification, the PCA-SVM model observing the whole brain (WB) region showed the highest performance (accuracy 92.38, specificity 92.87, sensitivity 92.87), followed by SVM with gray matter masking (GMM) (accuracy 92.22, specificity 92.13, sensitivity 92.28) for $A{\beta}$ positivity. To compare according to per-subject classification, the PCA-SVM with WB also showed the highest performance (accuracy 89.21, specificity 71.67, sensitivity 98.28), followed by PCA-SVM with GMM (accuracy 85.80, specificity 61.67, sensitivity 98.28) for $A{\beta}$ positivity. When comparing the area under curve (AUC), PCA-SVM with WB was the highest for per-slice classifiers (0.992), and the models except for SVM with WM were highest for the per-subject classifier (1.000). We can classify $^{18}F$-Florbetaben amyloid brain PET image for $A{\beta}$ positivity using PCA-SVM model, with no additional effects on GMM.

• 대한한방내과학회지
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• 제25권3호
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• pp.461-472
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• 2004

Objectives : For the screening of neuroprotective effects of medicinal herbs, the complex system of animal models suffer some disadvantages in controlling critical parameters such as blood pressure and body temperature. Additionally, application of drugs to the appropriate brain area sometimes is difficult, due to poor permeability though the blood brain barrier, and so potential protective effects might be masked. Methods : Organotypic hippocampal slice culture (OHSC) method has the advantages of being relatively easy to prepare and of maintaining the general structure, including tissue integrity and the connections between cells. Drugs can easily be applied and neuronal damage can easily be quantified by using tissues and culture media. This study demonstrates neuroprotective effects of Puerariae radix (葛根, PR), Salviae miltiorrhizae radix (丹蔘, SR), Rhei rhizoma (大黃, RR), and Bupleuri radix (柴胡, BR). These were screenedand compared to MK-801, antagonist of NMDA receptors, by using OHSC of 1 week-old Sprague-Dawley rats. Oxygen/glucose deprivation (OGD) were conducted in an anaerobic chamber $(85%\;N_2,\;10%\;CO_2\;and\;5%\;H_2)$ in a deoxygenated glucose-free medium for 60 minutes. Water extracts of each herbs were treated to culture media with $5\;{\mu}g/ml$ for 48 hours. Results : Neuronal cell death in the cultures was monitored by densitometric measurements of the cellular uptake of propidium iodide (PI). PI fluorescence images were obtained at 48 hours after the OGD and medicinal herb treatment. Also TUNEL-positive cells in the CAI and DG regions and LDH concentrations in culture media were measured at 48 hours after the OGD. According to measured data, MK-801, PR, SR and BR demonstrated significant neuroprotective effect against excessive neuronal cell death and apoptosis induced by the OGD insult. Especially, PR revealed similar neuroprotective effect to MK-801 and RR demonstrated weak neuroprotective effect. Conclusions : These results suggest that OHSC can be a suitable method for screening of neuroprotective effects of medicinal herbs. (This work was supported by the research program of Dongguk University and Grant 01-PJ9-PG1-01CO03-0003 from Ministry of Health & Welfare.)

• Investigative Magnetic Resonance Imaging
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• 제3권2호
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• pp.173-178
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• 1999

목적 : 후두엽의 허혈성 경색환자에서 시각피질의 기능적 자기공명영상의 유용성을 알아보고자 하였다. 대상 및 방법 : 후대뇌동맥의 시각파절 부위에 대한 혈류공급 장애로 인하여 시각피질의 허혈 또는 경색 증후를 보이는 환자 4명을 대상으로 하였다. 모든 환자는 안과적 시야검사를 받았으며 자기공명 혈관조영술(n=4)과 디지털 감산 혈관조영술(n=2)을 시행하여 혈관이상을 확인하였다. 기능적 자기공명영상은 2D-FLASH 기법(TRITE = 90/56 msec, TA = 8.32 see, $FOV{\;}={\;}240{\times}240,{\;}matrix{\;}No.={\;}64{\times}128$, slice thickness = 8mm)을 이용하였으며 초당 8 회로 점멸하는 적색 광자극원을 이용하여 5회의 광자극기간과 5회의 휴식기간을 번갈아 8차례, 총 40회의 검사를 시행하였다. 기능적 자기공명영상 소견을 안과적 시야검사 결과, 고식적 자기 공명영상 결과, 혈관조영술 결과와 비교 분석하였다. 결과 : 기능적 자기공명영상에서는 모든 환자가 혈관조영술에서 혈관이상을 보인쪽의 시각피질의 활성화가 이루어지지 않는 소견을 보였다. 그러나 이중에 2 환자는 고식적 자기공명영상이 정상이었다. 시야결손이 3 환자에서 관찰되었는데 이중 한 환자는 고식적 자기공명영상과 확산 자기공명영상에셔 정상소견이었지만 기능적 자기공명영상에서는 시야결손이 있는 쪽의 시각피 질의 촬성화가 이루어지지 않는 소견을 보였다. 결론 : 시각피질의 기능적 자기공명영상은 안과적 시야검사, T2강조영상 또는 확산강조명영상에서 발견되지 않는 시각피질의 허혈 또는 혈류잠재능 감소 상태를 감지할 수 있는 민감한 검사 방법이라고 생각된다.효율적이고 강력한 QA 도구로 자리 잡을 수 있을 것으로 기대된다.지하였으며 폐사율은 각각 1.9%, 1.9%, 2.9%와 1.0%로써 대조군의 4.8%에 비하여 낮은 수준을 보여 질병에 대한 저항능력이 향상되었다.kg/h로 분석되었다. 6. 건조작업 중에 소요되는 전력은 9.5~19.3 Wh/kg이었으며, 연료효율 6.9~9.3kg-$H_2$O/L와 열효율 50.2~65.1%에 의한 수분증발량은 124.0~125.4 kg-$H_2$O/h 로 나타났다. 7. 건조기의 열효율을 70%를 기준으로 평가한다면, 시작기의 열효율은 조금 낮은 수준이며, 열관리 계통의 개선을 필요로 하였다. 8. 제작된 계분건조기의 시작기를 15,000수 규모의 양계농장에서 사용한다면 관행의 계분처리 방법에 비하여 약 590,700(원/월)의 비용을 절감할 수 있을 것으로 추정되었다}0.09\;ml/1.5\;hr)$. 이상(以上)의 결과(結果)는 ethanol의 혈중농도(血中濃度)가 높을수록 더 심(甚)한 혈압강하작용(血壓降下作用)을 나타내며, ethanol 로 인(因)한 이뇨작용(利尿作用)도 ethanol 량(量)이 증가(增加)함에 따라 뇨량(尿量)도 증가(增加)함을 보여 주었다.ults showed that the overall quality of Sullungtang significantly decreased as the parity increased for Hanwoo cows. The Sullungtang extracted from bones of heifer had the best sensory scores as well as nutritional quality when compared

• Clinical and Experimental Pediatrics
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• 제49권5호
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• pp.558-564
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• 2006

목 적 : 경뇌 전자기 자극법은 변조 자기장을 이용하여 뇌세포에 대한 직접적인 영향을 주지 않으면서 중추 신경계를 자극할 수 있는 비침습적인 방법이다. 이전의 연구들은 대부분 생체 동물을 대상으로 수행되어져 왔으며 배양 조직에서의 연구는 별로 이루어진 바 없다. 이에 본 연구에서는 배양된 해마 절편에서 다른 주파수의 전자기 자극이 신경원에 미치는 영향과 약물에 의한 세포 손상 후 전자기 자극의 세포보호효과 여부에 대해 알아보고자 하였다. 방 법 : 생후 8일된 실험쥐의 대뇌를 적출하여 dissection microscope 하에서 양쪽 해마 부위를 분리하고 tissue chopper를 이용하여 $450{\mu}M$ 두께로 절편을 만든 후 Stoppini가 고안한 방법대로 배양을 시행하였다. 각각 5개의 건강한 해마 절편이 포함된 inserts를 선택하고, 전자기 자극군에 대해 0.67 Hz와 50 Hz의 주파수로 각각 배양 5일부터 3일 간격으로 6차례 전자기 자극을 가하였다. 또한, 배양 제 14일에 inserts 2개에 $100{\mu}M$ NMDA에 노출시키고 3일 후부터 3일 간격으로 insert 1개에 전자기 자극을 3차례 시행하였고 다른 1개의 insert와 대조군에는 자극을 가하지 않았다. 결 과 : 전자기 자극 후 신경원의 활성도를 알아보기 위해 NeuN 단백 발현을 western blotting을 이용하여 측정한 후 ${\beta}$-actin 단백 발현과의 비를 얻어 각 군에서 비교 분석하였다. 대조군($1.01{\pm}0.27$)에 비해 전자기 자극군에서 NeuN의 발현이 증가되어 있었으며, 특히 저주파 자극군($1.12{\pm}0.14$)에서보다 고주파 자극군($1.27{\pm}0.17$)에서 현저하였고 고주파 자극군에서는 대조군에 비해 통계적으로 유의한 증가를 보였다(P<0.05). 또한, NMDA 노출 후 실험군(전자기 자극군 : $1.15{\pm}0.27$, 전자기 비자극군 : $0.92{\pm}0.09$)에서 대조군($1.26{\pm}0.04$)에 비해 NeuN 발현이 감소되었으나 전자기 비자극군에서 더 많이 감소한 것을 알 수 있었다. 결 론 : 배양된 해마조직의 신경세포에 대한 전자기 자극은 저주파 자극군에 비해 고주파 자극군에서 대조군보다 통계적으로 유의한 수준의 NeuN 발현의 증가를 관찰할 수 있었고, NMDA 노출 후 전자기 자극을 가한 군에서 대조군보다 NeuN 발현 감소가 관찰되기는 하였으나 고주파 자극군에서는 통계적으로 유의하지 않은 정도였던 것으로 보아 전자기 자극이 신경원 활성을 증가시켜 신경세포의 발생 및 증식을 유도하며 세포 손상에 대한 신경보호효과도 보인다는 것을 알 수 있었다. 따라서 전자기 자극은 여러 신경 질환에 있어서 치료적 역할을 할 수 있는 가능성이 있다고 사료된다.

• 대한의용생체공학회:의공학회지
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• 제9권2호
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• pp.153-158
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• 1988

A three-dimensional surface is reconstructed from contour information as identified on two-dimensional computed tomographic slices. Gradient operator with curvature constraint would be applied to extract the contour automatically, and backtracking is also adopted to reduce the tracking error. The surface between the consecutive slice is efficiently reconstructed using a triangular surface tiles. Hidden surface elimination, shading and parallel projection of the reconstructed surface are provied on the display screen.

• 천문학회보
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• 제44권1호
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• pp.58.4-58.4
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• 2019

We present the application of the Point Spread Function (PSF) deconvolution method to the astronomical Integral Field Unit (IFU) Spectroscopy data focus on the restoration of the galaxy kinematics. We apply the Lucy-Richardson deconvolution algorithm to the 2D image at each wavelength slice. We make a set of mock IFU data which resemble the IFU observation to the model galaxies with a diverse combination of surface brightness profile, S/N, line-of-sight geometry and Line-Of-Sight Velocity Distribution (LOSVD). Using the mock IFU data, we demonstrate that the algorithm can effectively recover the stellar kinematics of the galaxy. We also show that lambda_R_e, the proxy of the spin parameter can be correctly measured from the deconvolved IFU data. Implementation of the algorithm to the actual SDSS-IV MaNGA IFU survey data exhibits the noticeable difference on the 2D LOSVD, geometry, lambda_R_e. The algorithm can be applied to any other regular-grid IFS data to extract the PSF-deconvolved spatial information.

• Journal of Microbiology and Biotechnology
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• 제18권9호
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• pp.1518-1521
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• 2008

Bacteria sense their population density and coordinate the expression of target genes, including virulence factors in Gram-negative bacteria, by the N-acylhomoserine lactones (AHLs)-dependent quorum sensing (QS) mechanism. In contrast, several soil bacteria are able to interfere with QS by enzymatic degradation of AHLs, referred to as quorum quenching. A potent AHL-degrading enzyme, AiiA, from Bacillus thuringiensis has been reported to effectively attenuate the virulence of bacteria by quorum quenching. However, little is known about the role of AiiA in B. thuringiensis itself. In the present study, an aiiA-defective mutant was generated to investigate the role of AHA in rhizosphere competence in the root system of pepper. The aiiA mutant showed no detectable AHL￢-egrading activity and was less effective for suppression of soft-rot symptom caused by Erwinia carotovora on the potato slice. On the pepper root, the survival rate of the aiiA mutant significantly decreased over time compared with that of wild type. Interestingly, viable cell count analysis revealed that the bacterial number and composition of E. carotovora were not different between treatments of wild type and the aiiA mutant. These results provide evidence that AHA can play an important role in rhizosphere competentce of B. thuringiensis and bacterial quorum quenching to Gram-negative bacteria without changing bacterial number or composition.

• Korean Journal of Radiology
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• 제21권7호
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• pp.891-899
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• 2020

Objective: To assess the diagnostic performance of a deep learning-based algorithm for automated detection of acute and chronic rib fractures on whole-body trauma CT. Materials and Methods: We retrospectively identified all whole-body trauma CT scans referred from the emergency department of our hospital from January to December 2018 (n = 511). Scans were categorized as positive (n = 159) or negative (n = 352) for rib fractures according to the clinically approved written CT reports, which served as the index test. The bone kernel series (1.5-mm slice thickness) served as an input for a detection prototype algorithm trained to detect both acute and chronic rib fractures based on a deep convolutional neural network. It had previously been trained on an independent sample from eight other institutions (n = 11455). Results: All CTs except one were successfully processed (510/511). The algorithm achieved a sensitivity of 87.4% and specificity of 91.5% on a per-examination level [per CT scan: rib fracture(s): yes/no]. There were 0.16 false-positives per examination (= 81/510). On a per-finding level, there were 587 true-positive findings (sensitivity: 65.7%) and 307 false-negatives. Furthermore, 97 true rib fractures were detected that were not mentioned in the written CT reports. A major factor associated with correct detection was displacement. Conclusion: We found good performance of a deep learning-based prototype algorithm detecting rib fractures on trauma CT on a per-examination level at a low rate of false-positives per case. A potential area for clinical application is its use as a screening tool to avoid false-negative radiology reports.