Distinction of directional coupling in sensorimotor networks between active and passive finger movements using fNIRS

The purpose of this study is to investigate cerebral cortex activation during active movement and passive movement by using a functional near-infrared spectroscopy (fNIRS). Tasks were the flexion/extension of the right hand finger by active movement and passive movement. Oxy-hemoglobin concentration changes calculated from fNIRS and analyzed the activation and connectivity so as to understand dynamical brain relationship. The results demonstrated that the brain activation in passive movements is similar to motor execution. During active movement, the estimated causality patterns showed significant causality value from the supplementary motor area (SMA) to the primary motor cortex (M1). During the passive movement, the causality from the primary somatosensory cortex (S1) to the primary motor cortex (M1) was stronger than active movement. These results demonstrated that active and passive movements had a direct effect on the cerebral cortex but the stimulus pathway of active and passive movement is different. This study may contribute to better understanding how active and passive movements can be expressed into cortical activation by means of fNIRS. © 2018 Optical Society of America under the terms of the OSA Open Access Publishing Agreement.1

The difference in cortical activation pattern for complex motor skills: A functional near- infrared spectroscopy study

The human brain is lateralized to dominant or non-dominant hemispheres, and controlled through large-scale neural networks between correlated cortical regions. Recently, many neuroimaging studies have been conducted to examine the origin of brain lateralization, but this is still unclear. In this study, we examined the differences in brain activation in subjects according to dominant and non-dominant hands while using chopsticks. Fifteen healthy right-handed subjects were recruited to perform tasks which included transferring almonds using stainless steel chopsticks. Functional near-infrared spectroscopy (fNIRS) was used to acquire the hemodynamic response over the primary sensory-motor cortex (SM1), premotor area (PMC), supplementary motor area (SMA), and frontal cortex. We measured the concentrations of oxy-hemoglobin and deoxy-hemoglobin induced during the use of chopsticks with dominant and non-dominant hands. While using the dominant hand, brain activation was observed on the contralateral side. While using the non-dominant hand, brain activation was observed on the ipsilateral side as well as the contralateral side. These results demonstrate dominance and functional asymmetry of the cerebral hemisphere. © 2019, The Author(s).1

Retrieval of NO2 Column Amounts from Ground-Based Hyperspectral Imaging Sensor Measurements

Total column amounts of NO2 (TCN) were estimated from ground-based hyperspectral imaging sensor (HIS) measurements in a polluted urban area (Seoul, Korea) by applying the radiance ratio fitting method with five wavelength pairs from 400 to 460 nm. We quantified the uncertainty of the retrieved TCN based on several factors. The estimated TCN uncertainty was up to 0.09 Dobson unit (DU), equivalent to 2.687 ?? 1020 molecules m???2) given a 1?? error for the observation geometries, including the solar zenith angle, viewing zenith angle, and relative azimuth angle. About 0.1 DU (6.8%) was estimated for an aerosol optical depth (AOD) uncertainty of 0.01. In addition, the uncertainty due to the NO2 vertical profile was 14% to 22%. Compared with the co-located Pandora spectrophotometer measurements, the HIS captured the temporal variation of the TCN during the intensive observation period. The correlation between the TCN from the HIS and Pandora also showed good agreement, with a slight positive bias (bias: 0.6 DU, root mean square error: 0.7 DU)

COMPARISON OF ANGULAR KINEMATIC PATTERNS BETWEEN CARVING TURN AND SKIDDING TURN DURING ALPINE SKIING

The purpose of this study was to investigate the movement patterns between segments (lower spine, pelvis, thigh, shank) and ski using the relative angular displacement on anteroposterior and vertical axis. Fourteen alpine ski instructors were participated in this study. Eight inertial measurement units were used to measure kinematic variables. Each skier was asked to perform ten carving turns and ten skidding turns on the groomed 15°slope, respectively. On the vertical axis, relative angular displacement of lower spine-ski was significantly increased during carving turn, whereas relative angular displacement of shank-ski was significantly increased during skidding turn. On the anteroposterior axis, relative angular displacement of lower spine-ski, pelvis-ski and thigh-ski were significantly increased during carving turn

Hemispheric asymmetry in hand preference of right-handers for passive vibrotactile perception: an fNIRS study

Hemispheric asymmetry in hand preference for passive cutaneous perception compared to active haptic perception is not well known. A functional near-infrared spectroscopy was used to evaluate the laterality of cortical facilitation when 31 normal right-handed participants were involved in 205 Hz passive vibrotactile cutaneous stimuli on their index fingers of preferred and less-preferred hand. Passive cutaneous perception resulted that preferred (right) hand stimulation was strongly leftward lateralized, whereas less-preferred (left) hand stimulation was less lateralized. This confirms that other manual haptic exploration studies described a higher hemispheric asymmetry in right-handers. Stronger cortical facilitation was found in the right primary somatosensory cortex (S1) and right somatosensory association area (SA) during left-hand stimulation but not right-hand stimulation. This finding suggests that the asymmetric activation in the S1 and SA for less-preferred (left) hand stimulation might contribute to considerably reinforce sensorimotor network just with passive vibrotactile cutaneous stimulation. © 2020, The Author(s).1

Session D5: Current Status of Fish Passages in South Korea

Abstract: Weirs are important for countries that agriculture is the primary industry due to the stable supply of water to agricultural fields. Because agriculture is still important in Korean peninsula, weirs have been constructing until now from small streams to large rivers. However, only limited fish passages were installed in weirs, and there were no managements. As a results, streams and rivers have become highly fragmented, with fish migration being severely impeded. Thus, ministry of agriculture, food and rural affairs investigated entire fish passages in Korea in 2010-2011, and estimated current status and problems. A total of 33,718 weirs were installed (until year 2012), and this means that weirs are arithmetically located every 0.81km of the total stream length in Korea. Fish passages, however, were constructed only in 4,496 weirs (13.3% of installation rate). The weir type fish passages with Ice- Harbor type fishways (8.1%) which are favoured nowadays was showed the greatest number (36%), and the vertical slot type passages was in the second place (31%). The denil type and nature-like type were rarely installed. Only 18.1% of installed fish passages were left whole, and urgent repair is needed for 56.7%. Fish passages of 31.3% were incorporated into the recommended slope range of Korea (1:20). Most of problems are related discharge, poor entrance, breakage and sedimentation. With these structural problems, discontinuous installation of fish passages generates poor continuity of streams. Currently, to improve stream connectivity many projects from Korean government are now conducting and preparing, and additionally development of fish passages specialized for Korean fishes are required

Revealing salt-expedited reduction mechanism for hollow silicon microsphere formation in bi-functional halide melts

The thermochemical reduction of silica to silicon using chemical reductants requires high temperature and has a high activation energy, which depends on the melting temperature of the reductant. The addition of bi-functional molten salts with a low melting temperature may reduce the required energy, and several examples using molten salts have been demonstrated. Here we study the mechanism of reduction of silica in the presence of aluminum metal reductant and aluminum chloride as bi-functional molten salts. An aluminum-aluminum chloride complex plays a key role in the reduction mechanism, reacting with the oxygen of the silica surfaces to lower the heat of reaction and subsequently survives a recycling step in the reaction. This experimentally and theoretically validated reaction mechanism may open a new pathway using bi-functional molten salts. Furthermore, the as-synthesized hollow porous silicon microsphere anodes show structural durability on cycling in both half/full cell tests, attributed to the high volume-accommodating ability

Risk factors for transmission in a COVID-19 cluster infection in a high school in the Republic of Korea

Objectives This study aimed to examine the scale, characteristics, risk factors, and modes of transmission in a coronavirus disease 2019 (COVID-19) outbreak at a high school in Seoul, Republic of Korea. Methods An epidemiological survey was conducted of 1,118 confirmed cases and close contacts from a COVID-19 outbreak at an educational facility starting on May 31, 2021. In-depth interviews, online questionnaires, flow evaluations, and CCTV analyses were used to devise infection prevention measures. Behavioral and spatial risk factors were identified, and statistical significance was tested. Results Among 3rd-year students, there were 33 confirmed COVID-19 cases (9.6%). Students who used a study room in the annex building showed a statistically significant 4.3-fold elevation in their relative risk for infection compared to those who did not use the study room. Moreover, CCTV facial recognition analysis confirmed that 17.8% of 3rd-year students did not wear masks and had the lowest percentage of mask-wearers by grade. The air epidemiological survey conducted in the study room in the annex, which met the 3 criteria for a closed space, confirmed that there was only 10% natural ventilation due to the poor ventilation system. Conclusion To prevent and manage the spread of COVID-19 in educational facilities, advance measures that consider the size, operation, and resources of each school are crucial. In addition, various survey methodologies should be used in future studies to quickly analyze a wider range of data that can inform an evidence-based quarantine response