• 대한물리의학회지
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• 제12권1호
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• pp.51-59
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• 2017

PURPOSE: This study compared cognitive task-directed functional motor control ability for reaching and kicking movements in younger and older adults. METHODS: Subjects were divided into two groups of younger and older adults, with 13 subjects in each group. Subjects were required to perform a dual task combining a functional movement and cognitive component. The task consisted of reaching and kicking movements. Participants performed indicated movements when a target appeared on a monitor. The target randomly appeared on the monitor every 10 seconds. The total performance time (TPT), joint angular velocity (JAV), and muscle activation time were used to evaluate motor control ability. RESULTS: There were significant differences in all evaluation factors in a comparison of younger and older adults (p<.05). TPT was significantly shorter in older adults, and JAV and muscle activation time were significantly slower than that in the younger adult group. Although the results for older adults were within the normal range for functional assessment, their motor control abilities were significantly worse for cognitive tasks compared with those of younger adults. CONCLUSION: The results of this study indicated that a motor control assessment tool using a cognitive task would be helpful in assessment of motor control ability in healthy older adults.

• The Korean Journal of Legal Medicine
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• 제42권4호
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• pp.146-152
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• 2018

We investigated the neural correlates of accurate eyewitness memory retrieval using functional near-infrared spectroscopy. We analyzed oxygenated hemoglobin ($HbO_2$) concentration in the prefrontal cortex during eyewitness memory retrieval task and examined regional $HbO_2$ differences between observed objects (target) and unobserved objects (lure). We found that target objects elicited increased activation in the bilateral ventrolateral prefrontal cortex, which is known for monitoring retrieval processing via bottom-up attentional processing. Our results suggest bottom-up attentional mechanisms could be different during accurate eyewitness memory retrieval. These findings indicate that investigating retrieval mechanisms using functional near-infrared spectroscopy might be useful for establishing an accurate eyewitness recognition model.

• Carbon letters
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• 제28권
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• pp.116-120
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• 2018

Nitrogen-doped carbons have attracted much attention due to their novel application in relation to gas storage. In this study, nitrogen-doped porous carbons were synthesized using SBA-15 as a template, polypyrrole as the carbon and nitrogen precursor, and KOH as an activating agent. The effect of the activation temperature ($600-850^{\circ}C$) on the $CO_2$ adsorption capacity of the obtained porous carbons was studied. Characterization of the resulting carbons showed that they were micro-/meso-porous carbon materials with a well-developed pore structure that varied with the activation temperature. The highest surface area of $1488m^2g^{-1}$ was achieved at an activation temperature of $800^{\circ}C$ (AC-800). The nitrogen content of the activated carbon decreased from 4.74 to 1.39 wt% with an increase in the activation temperature from 600 to $850^{\circ}C$. This shows that nitrogen is oxidized and more easily removed than carbon during the activation process, which indicates that C-N bonds are more easily ruptured at higher temperatures. Furthermore, $CO_2$ adsorption isotherms showed that AC-800 exhibited the best $CO_2$ adsorption capacity of $110mg\;g^{-1}$ at 298 K and 1 bar.

• Nutrition Research and Practice
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• 제11권5호
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• pp.381-387
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• 2017

BACKGROUND/OBJECTIVES: Vascular dementia (VaD) caused by reduced blood supply to the brain manifests as white matter lesions accompanying demyelination and glial activation. We previously showed that arabinoxylan consisting of arabinose and xylose, and arabinose itself attenuated white matter injury in a rat model of VaD. Here, we investigated whether larch arabinogalactan (LAG) consisting of arabinose and galactose could also reduce white matter injury. MATERIALS/METHODS: We used a rat model of bilateral common carotid artery occlusion (BCCAO), in which the bilateral common carotid arteries were exposed and ligated permanently with silk sutures. The rats were fed a modified AIN-93G diet supplemented with LAG (100 mg/kg/day) for 5 days before and 4 weeks after being subjected to BCCAO. Four weeks after BCCAO, the pupillary light reflex (PLR) was measured to assess functional consequences of injury in the corpus callosum (cc). Additionally, Luxol fast blue staining and immunohistochemical staining were conducted to assess white matter injury, and astrocytic and microglial activation, respectively. RESULTS: We showed that white matter injury in the the cc and optic tract (opt) was attenuated in rats fed diet supplemented with LAG. Functional consequences of injury reduction in the opt manifested as improved PLR. Overall, these findings indicate that LAG intake protects against white matter injury through inhibition of glial activation. CONCLUSIONS: The results of this study support our hypothesis that cell wall polysaccharides consisting of arabinose are effective at protecting white matter injury, regardless of their origin. Moreover, LAG has the potential for development as a functional food to prevent vascular dementia.

• The Korean Journal of Physiology and Pharmacology
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• 제5권5호
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• pp.367-371
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• 2001

The chromosome 7-linked long QT syndrome (LQT2) is caused by mutations in the human ether-a- go-go-related gene (HERG) that encodes the rapidly activating delayed rectifier $K^+$ current, $I_{Kr},$ in cardiac myocytes. Different types of mutations have been identified in various locations of HERG channel. One of the mechanisms for the loss of normal channel function is due to membrane trafficking of channel protein. The decreased channel function in some deletion mutants appears to be due to loss of coupling with wild type HERG to form the functional channel as the tetramer. Most of missense mutants with few exceptions could interact with wild type HERG to form functional tetramer and caused dominant negative suppression with co-injection with wild type HERG showing variable effects on current amplitude, voltage dependence, and kinetics of activation and inactivation. Two missense mutants at pore regions of HERG found in Japanese LQT2 (A614V and V630L) showed accentuated inward rectification due to a negative shift in steady-state inactivation and fast inactivation. One mutation in S4 region (R534C) produced a negative shift in current activation, indicating the S4 serving as the voltage sensor and accelerated deactivation. The C-terminus mutation, S818L, could not express the current by mutant alone and did not show dominant negative suppression with co-injection of equal amount of wild type cRNA. Co-injection of excess amount of mutant with wild type produced dominant negative suppression with a shift in voltage dependent activation. Therefore, multiple mechanisms are involved in different mutations and functional abnormality in LQT2. Further characterization with the interactions between various mutants in HERG and the regulatory subunits of the channels (MiRP1 and minK) is to be clarified.

• Investigative Magnetic Resonance Imaging
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• 제1권1호
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• pp.114-118
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• 1997

목적: 기능적 MR 영상은 외부자극에 따라, 이에 상응하는 특정한 뇌피질 부위의 혈류량의 변화를 신호강도의 차이로 나타내는 방법이다. 시각피질에 대한 기능적 MR은 환자가 광자극을 응시함으로써 수행될 수 있는 것으로, 이의 수행에는 적절한 형태의 광자극원이 필수적이다. 이에 저자는 광자극원의 크기가 시각피질 활성화에 영향을 미칠 수 있는지 알아보기 위하여 본 연구를 하였다. 대상 및 방법: 정상적인 시력을 가진 자원자 5명을 대상으로 시각활성화 기능적 MR을 시행하였다. 광자극원은 $11{\times}8cm$ 크기의 기판에 적색 LED(light-emitting diodes) 39개를 박고 직류전원을 사용하도록 만들었다. 이를 크기에 따라 full field, half field 및 focal central field의 3가지로 구분하고 8Hz로 점멸하였다. EPI 기법으로 6회의 광자극 기간과 6회의 휴식기간을 번갈아 3차례 시행하여 총 36회의 검사를 하고, Z-score로 통계처리하였다. 이 때 얻은 활성화 영상을 같은 부위의 T1강조영상에 결합시켰다. 각 경우에서 시각피질에서 활성화된 pixel의 수를 full field, half field 및 focal central field에서 얻어진 pixel 수의 합으로 나누어 활성화지수를 구하였다. 이 활성화지수를 토대로 광원크기와의 관계를 분석하였다. 결과: Full field로 자극을 주었을 때 시각피질의 평균 신호강도의 증가는 약 9.6%였다. 4명에서 활성화지수는 full field, half field, focal central field의 순으로 감소하였으며, 나머지 1명에서는 half field 시의 값이 full field 시의 값보다 컸다. 광원크기에 따른 활성화지수의 범위는 full field 43-73%(평균 55%), half field 22-40%(평균 32%), focal central field 5-24%(평균 13%)였다. 결론: 기능적 MR영상을 이용하여 시각피질의 활성화를 용이하게 확인할 수 있었으며 광자극원의 크기에 따라 증가되는 시각피질 활성화를 입증할 수 있었다.

• Journal of Plant Biotechnology
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• 제34권4호
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• pp.285-291
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• 2007

본 연구는 아그로박테리움 공동배양법을 이용한 기능획득 인삼 모상근의 대량생산을 위한 조건 확립에 대한 것이다. 일반적으로, 인삼과 같이 형질전환을 통한종자의 확보가 어려운 식물에서는 loss-of-function을 이용한 기능유전체 연구에 한계가 있다. 한편, 유전자의 기능을 활성화시키는 방법 (gain-of-function)인 activation tagging 기술은 이러한 문제점을 극복할 수 있는 대안이 될 수 있으며, Agrobacterium rhizogenes를 이용한 모상근 생산 시스템은 대량의 돌연변이체를 안정적으로 용이하게 얻을 수 있다는 점에서 최적의 시스템이라고 할 수 있다. 본 연구에서는 activation-tagging된 효율적인 형질전환 모상근 생산에 있어서의 최적의 아그로박테리움 균주 및 인삼조직, 배지조성 등에 대한 조건을 확립하였으며, 다양한 배지에서의 형질전환 모상근의 생장률 및 분지율, 표현형 등을 조사하였다. 엽병 절편을 activation-tagging vector pKH01을 가지고 있는 A. rhizogenes R1000와 공동배양하였을 때 배양 4주후 85.9%의 빈도로 모상근이 생산되었다. 모상근의 최대 생장과 분지도를 나타내는 배양조건을 조사한 바 엽병절편을 1/2 SH 배지에서 4주 배양하였을 때 왕성하게 생장하였으며 2.6의 분지도를 보여주었다. 최종적으로 1,989개체의 독립적인 형질전환 모상근 line을 생산하였으며, 이들 모상근 line은 인삼 진세노사이드 생합성 관련 유전자의 발굴 및 기능해석에 유용하게 쓰일 것이다.

• 한국정밀공학회지
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• 제22권7호
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• pp.200-207
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• 2005

This study compares two different methods of measuring brain-BOLD activation. By comparing two different methods of measurement i.e., one method calculating the neural activation area (the number of activated voxels), while the other measured the neural activation intensity (the mean intensity of selected activated yokels), this study identified the more precise method of measuring brain activation which results from the completion of a visuospatial task. 16 right-handed male college students (mean age 23.2 years) participated in this study as subjects. Functional brain images were scanned on them using a 3T MRI single-shot EPI method. No correlation was found between the levels of cognitive performance and number of activated yokels in the activated brain areas. However, a significant correlation was found between the levels of cognitive performance and the mean intensity of selected activated yokels in the parietal, frontal, and other areas. In conclusion, the method of mean intensity was considered a better index of brain activity rather than the activated yokels measurement method.

• 대한의용생체공학회:학술대회논문집
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• 대한의용생체공학회 1997년도 춘계학술대회
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• pp.92-94
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• 1997

By measuring the increase of regional cerebral blood flow (rCBF) during the activation tasks, we can describe the brain regions that participate in certain specific functions. In this study, we composed the functional maps of verbal and nonverbal memory by performing the rCBF positron emission tomography (PET) activation studies and analyzing the differences between control and each activation state. Successive four tasks, which consist of one control state and three different activation tasks, were performed on 6 normal volunteers. All images were spatially normalized on standard atlas and the differences between control and activation states were statistically analyzed. The verbal memory activated predominantly left-sided structures, especially left superior temporal cortex, and the nonverbal short-term memory activated the right frontal cortex. Also, some regions ,where is thought to be related with short-term memory system, such as cingulate gyrus and hippocampus were activated. We conclude that biological validity of the brain regions for verbal and nonverbal memory could be tested using rCBF PET imaging technique and statistical analysis.

• Biomolecules & Therapeutics
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• 제32권1호
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• pp.56-64
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• 2024

Biased signaling or functional selectivity refers to the ability of an agonist or receptor to selectively activate a subset of transducers such as G protein and arrestin in the case of G protein-coupled receptors (GPCRs). Although signaling through arrestin has been reported from various GPCRs, only a few studies have examined side-by-side how it differs from signaling via G protein. In this study, two signaling pathways were compared using dopamine D₂ receptor (D₂R) mutants engineered via the evolutionary tracer method to selectively transduce signals through G protein or arrestin (D₂G and D₂Arr, respectively). D₂G mediated the inhibition of cAMP production and ERK activation in the cytoplasm. D₂Arr, in contrast, mediated receptor endocytosis accompanied by arrestin ubiquitination and ERK activation in the nucleus as well as in the cytoplasm. D₂Arr-mediated ERK activation occurred in a manner dependent on arrestin3 but not arrestin2, accompanied by the nuclear translocation of arrestin3 via importin1. D₂R-mediated ERK activation, which occurred in both the cytosol and nucleus, was limited to the cytosol when cellular arrestin3 was depleted. This finding supports the results obtained with D₂Arr and D₂G. Taken together, these observations indicate that biased signal transduction pathways activate distinct downstream mechanisms and that the subcellular regions in which they occur could be different when the same effectors are involved. These findings broaden our understanding on the relation between biased receptors and the corresponding downstream signaling, which is critical for elucidating the functional roles of biased pathways.