Cerebral hemodynamic responses to seizure in the mouse brain: simultaneous near-infrared spectroscopy-electroencephalography study.

Lee, Seungduk,Lee, Mina,Koh, Dalkwon,Kim, Beop-Min,Choi, Jee Hyun SPIE--the International Society for Optical Engine 2010 JOURNAL OF BIOMEDICAL OPTICS Vol.15 No.3

<P>We applied near-infrared spectroscopy (NIRS) and electroencephalography (EEG) simultaneously on the mouse brain and investigated the hemodynamic response to epileptic episodes under pharmacologically driven seizure. gamma-butyrolactone (GBL) and 4-aminopyridine (4-AP) were applied to induce absence and tonic-clonic seizures, respectively. The epileptic episodes were identified from the single-channel EEG, and the corresponding hemodynamic changes in different regions of the brain were characterized by multichannel frequency-domain NIRS. Our results are the following: (i) the oxyhemoglobin level increases in the case of GBL-treated mice but not 4-AP-treated mice compared to the predrug state; (ii) the dominant response to each absence seizure is a decrease in deoxyhemolobin; (iii) the phase shift between oxy- and deoxyhemoglobin reduces in GBL-treated mice but no 4-AP-treated mice; and (iv) the spatial correlation of hemodynamics increased significantly in 4-AP-treated mice but not in GBL-treated mice. Our results shows that spatiotemporal tracking of cerebral hemodynamics using NIRS can be successfully applied to the mouse brain in conjunction with electrophysiological recording, which will support the study of molecular, cellular, and network origin of neurovascular coupling in vivo.</P>

Characterization of Lipophilic Nutraceutical Compounds in Seeds and Leaves of Perilla frutescens

Seungduk Um,Shiva Ram Bhandari,Nam-Hoon Kim,Tae-Jin Yang,Ju Kyoung Lee,Young-Sang Lee 한국원예학회 2013 원예과학기술지 Vol.31 No.2

Perilla frutescens, which comprises var. frutescens and var. crispa, has been cultivated traditionally in Asian countries as an edible oil, leaf vegetable, and medicinal crop. To evaluate the lipophilic phytonutrient properties of P. frutescens, we selected 54 Perilla accessions [19 landraces of var. frutescens (FL), 22 weedy type var. frutescens (FW), 9 weedy type var. crispa (CW), 2 cultivars of var. frutescens widely cultivated for seed oil (FCS), and 2 cultivars of var. frutescens cultivated as a leaf vegetable (FCL)] and analyzed their seeds and leaves for vitamin E, squalene, and phytosterols. Among the four vitamin E isomers analyzed, γ-tocopherol was the major form of vitamin E in seeds, whereas α-tocopherol was the major form in leaves of all types of P. frutescens. The highest total vitamin E content in seeds was present in FL (170.0 ㎎ㆍ㎏⁻¹), whereas that in leaves was highest in FCL (358.1 ㎎ㆍ㎏⁻¹). The highest levels of squalene in seeds and leaves were in FL (65.5 ㎎ㆍ㎏⁻¹) and CW (719.3 ㎎ㆍ㎏⁻¹), respectively. Among the three phytosterols, β-sitosterol occurred in the highest amount in both leaves and seeds of all of the crop types. Phytonutrient contents were comparatively higher in leaves than in seeds of all crop types. All of these results suggest that the consumption of leaves and seeds of Perilla crops could be beneficial to human health, as Perilla possesses considerable amounts of various lipophilic compounds.

Hemodynamic Responses of Rat Brain Measured by Near-infrared Spectroscopy During Various Whisker Stimulations

Seungduk Lee,김법민,Dalkwon Koh,권기운,이현주,Yiran Lang,신형철 한국광학회 2009 Current Optics and Photonics Vol.13 No.1

NIRS (Near-infrared spectroscopy) is a relatively, new, non-invasive, and non-ionizing method of measuring hemodynamic responses in thick biological tissues such as the cerebral cortex. In this study, we measured the hemodynamic responses of the rat barrel cortex to whisker stimulation by using a frequency-domain NIRS system. We designed multiple optical probes comprising multi- mode optical fibers and manipulating arms, both of which can be easily applied to small animals. Various electrical stimulations were applied to rat whiskers at different voltage levels and stimulation frequencies. Our results show that the hemodynamic responses are highly dependent on the stimulation voltage level, and not so much on stimulation frequency. This paper suggests that NIRS technology is highly suitable for the study of small animal brains.

Characterization of Lipophilic Nutraceutical Compounds in Seeds and Leaves of Perilla frutescens

Um, Seungduk,Bhandari, Shiva Ram,Kim, Nam-Hoon,Yang, Tae-Jin,Lee, Ju Kyoung,Lee, Young-Sang Korean Society of Horticultural Science 2013 원예과학기술지 Vol.31 No.2

Perilla frutescens, which comprises var. frutescens and var. crispa, has been cultivated traditionally in Asian countries as an edible oil, leaf vegetable, and medicinal crop. To evaluate the lipophilic phytonutrient properties of P. frutescens, we selected 54 Perilla accessions [19 landraces of var. frutescens (FL), 22 weedy type var. frutescens (FW), 9 weedy type var. crispa (CW), 2 cultivars of var. frutescens widely cultivated for seed oil (FCS), and 2 cultivars of var. frutescens cultivated as a leaf vegetable (FCL)] and analyzed their seeds and leaves for vitamin E, squalene, and phytosterols. Among the four vitamin E isomers analyzed, ${\gamma}$-tocopherol was the major form of vitamin E in seeds, whereas ${\alpha}$-tocopherol was the major form in leaves of all types of P. frutescens. The highest total vitamin E content in seeds was present in FL ($170.0mg{\cdot}kg^{-1}$), whereas that in leaves was highest in FCL ($358.1mg{\cdot}kg^{-1}$). The highest levels of squalene in seeds and leaves were in FL ($65.5mg{\cdot}kg^{-1}$) and CW ($719.3mg{\cdot}kg^{-1}$), respectively. Among the three phytosterols, ${\beta}$-sitosterol occurred in the highest amount in both leaves and seeds of all of the crop types. Phytonutrient contents were comparatively higher in leaves than in seeds of all crop types. All of these results suggest that the consumption of leaves and seeds of Perilla crops could be beneficial to human health, as Perilla possesses considerable amounts of various lipophilic compounds.

동적 코디네이터 기반의 능동형 복제를 통한 결함허용 시스템 설계

류승덕 ( Seungduk You ),이인환 ( Inhwan Lee ) 한국정보처리학회 2005 한국정보처리학회 학술대회논문집 Vol.12 No.2

본 논문에서는 인터넷 기반의 예약 시스템 설계시 가용성(Availability)을 높이기 위해 능동형 레플리케이션(Active Replication)기법을 이용하였으며 서비스 요청에 대한 응답지연 시간을 줄이고자 레플리케이션 그룹 내에 동적 코디네이터(Dynamic Coordinator)를 이용하였다. 실험 결과는 코디네이터를 사용하였을 경우 33% 빠른 응답속도를 보였다. 그러나 코디네이터 선출 방식을 동적으로 하였을 경우 코디네이터 선출시 사용되는 많은 메시지로 인하여 79.98% 증가된 지연시간을 확인하였다.

Estimation of directional coupling between cortical areas using Near-Infrared Spectroscopy (NIRS)

Im, Chang-Hwan,Jung, Young-Jin,Lee, Seungduk,Koh, Dalkwon,Kim, Do-Won,Kim, Beop-Min The Optical Society 2010 Optics express Vol.18 No.6

<P>This study invesitigated the feasibility of measuring directional coupling between cortical areas with near-infrared spectroscopy (NIRS). Cerebral hemodynamic responses were recorded at the primary somatosensory cortex (S1), secondary somatosensory cortex (S2), and primary motor cortex (M1) regions of the rat barrel cortex during electrical stimulation of rat whiskers. Deoxyhemoglobin concentration changes were calculated from NIRS recordings and the Granger causality based on the multivariate autoregressive (MVAR) model was used to estimate the effective causal connectivity among S1, S2, and M1. The estimated causality patterns of seven rats showed consistent unidirectional coupling between the somatosensory areas and the motor areas (S1 and S2-->M1), which coincided well with our hypothesis because the rats' motor function was completely anesthetized. Our preliminary results suggest that cortico-cortical directional coupling can be successfully investigated with NIRS.</P>

윈도우즈 시스템의 보안 강화를 위한 정책 제어 시스템 설계

박정진(Jungjin Park),박진섭(Jinsub Park),이승혁(Seunghyeok Lee),백승덕(Seungduk Baek) 한국정보과학회 2007 한국정보과학회 학술발표논문집 Vol.34 No.2D

인터넷 및 네트워크의 사용이 일반화됨으로써 컴퓨터 시스템을 사용하지 않는 분야 및 사용자가 없을 정도이다. 컴퓨터 시스템을 사용함에 있어 순기능이 있는 반면 이에 대한 역기능 또한 급속하게 증가하고 있다. 역기능 중 가장 심각한 문제를 발생시킬 수 있는 부분이 웜 및 바이러스, 또한 악의적인 목적이 해킹 등이 있다. 이러한 문제를 해결하기 위해 각종 보안시스템 및 소프트웨어를 도입하여 사용하고 있지만 이에 앞서 일반적으로 사용하는 윈도우즈 시스템 자체에 포함되어 있는 각종 보안 설정을 통하여 근본적인 원인을 해결할 수 있다면 악의적인 목적에 의한 피해는 미연에 방지할 수 있을 것이다. 본 논문에서는 이러한 위도우즈 시스템 자체에 있는 보안설정 기능을 자동으로 설정 및 제어할 수 있는 시스템을 제안하고자 한다.

Development of Wireless NIRS System with Dynamic Removal of Motion Artifacts

Beop-Min Kim,Choong-Ki Kim,Dalkwon Koh,Seungduk Lee 대한의용생체공학회 2011 Biomedical Engineering Letters (BMEL) Vol.1 No.4

Purpose Along with recent advances in neuroscience, nearinfrared spectroscopy (NIRS) has been widely used to measure changes in cerebral oxygenation non-invasively. An NIRS system can be constructed to be portable unlike other imaging modalities, but its signals are often distorted by artifacts generated by arterial pulsation, vasomotion and head motion. To overcome these problems, we have developed a wireless NIRS system with a real time accelerometer that allows noise reduction. Methods Our wireless NIRS system includes a microcontroller,a Bluetooth communication, a fPCB (flexible printed circuit board), an accelerometer, batteries, LEDs (light emitting diode) and PDs (photodiode). Distorted signal caused by head motion was removed by active noise cancellation (ANC)algorithm. Results Two different tasks, arterial occlusion and brain hypoxia, were tested to validate the performance of our system. During arterial occlusion and breath holding, the NIRS signal showed corresponding hemodynamic changes such as increase in deoxy-hemoglobin (Hbr) and decrease in oxy-hemoglobin (HbO2) concentrations. Signal distortions generated by head motion were effectively removed. Conclusions Wireless NIRS system combined with real time noise cancellation algorithm has great potential to be utilized in brain-computer interface (BCI) for physically challenged people, dynamic exercise tasks and cognitive studies for children. Furthermore we expect the system will be highly applicable in neuroscience.