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Brain organoids derived from human pluripotent stem cells provide a highly valuable in vitro model to recapitulate human brain development and neurological diseases. However, the current systems for brain organoid culture require further improvement for the reliable production of high-quality organoids. Here, we demonstrate two engineering elements to improve human brain organoid culture, (1) a human brain extracellular matrix to provide brain-specific cues and (2) a microfluidic device with periodic flow to improve the survival and reduce the variability of organoids. A three-dimensional culture modified with brain extracellular matrix significantly enhanced neurogenesis in developing brain organoids from human induced pluripotent stem cells. Cortical layer development, volumetric augmentation, and electrophysiological function of human brain organoids were further improved in a reproducible manner by dynamic culture in microfluidic chamber devices. Our engineering concept of reconstituting brain-mimetic microenvironments facilitates the development of a reliable culture platform for brain organoids, enabling effective modeling and drug development for human brain diseases. Brain organoids derived from human pluripotent stem cells can model human brain development and disease, though current culture systems fail to ensure reliable production of high-quality organoids. Here the authors combine human brain extracellular matrix and culture in a microfluidic device to promote structural and functional maturation of human brain organoids.

Enzymatically induced carbonate precipitation (EICP) using urea hydrolysis is a well-known bio-cementation process that not only promotes the precipitation of calcium carbonate (CaCO 3 ) but can provide excess calcium cations for further reaction depending on the substrate constituents and reaction stage. This study presents the EICP recipe to contain sulfate ions in landfill leachate sufficiently using remaining calcium cations and a series of tests were conducted to validate its ability to retain sulfates. The reaction rate for 1 M CaCl 2 and 1.5 M urea was identified by controlling the purified urease content and the curing time of the EICP process. The results showed that 0.3 g/L of purified urease produced 46% CaCO 3 and reduced sulfate ions by 77% after 3 days of curing. The shear stiffness in EICP-treated sand was enhanced 13 times by CaCO 3 precipitation followed by 1.12 times increment due to subsequent precipitation of gypsum (CaSO 4 ·2H 2 O) crystals implying sulfate containment. A cost-efficient EICP treatment using soybean crude urease instead of lab-grade purified urease exhibited lower sulfate removal efficiency (i.e., 18%) with only nominal formation of gypsum in the EICP-treated sand. The addition of gypsum powder was effective in increasing sulfate removal by 40% when soybean crude urease was used for EICP.

The Balloon Analogue Risk Task (BART) provides a reliable and ecologically valid model for the assessment of individual risk-taking propensity and is frequently used in neuroimaging and developmental research. Although the test-retest reliability of risk-taking behavior during the BART is well established, the reliability of brain activation patterns in response to risk-taking during the BART remains elusive. In this study, we used functional magnetic resonance imaging (fMRI) and evaluated the test-retest reliability of brain responses in 34 healthy adults during a modified BART by calculating the intraclass correlation coefficients (ICC) and Dice’s similarity coefficients (DSC). Analyses revealed that risk-induced brain activation patterns showed good test-retest reliability (median ICC ​= ​0.62) and moderate to high spatial consistency, while brain activation patterns associated with win or loss outcomes only had poor to fair reliability (median ICC ​= ​0.33 for win and 0.42 for loss). These findings have important implications for future utility of the BART in fMRI to examine brain responses to risk-taking and decision-making. •Risk-taking behavior during the BART showed excellent test-retest reliability.•Brain responses to risk-taking during the BART showed good test-retest reliability.•Brain responses to risk-taking showed moderate to high spatial consistency.•Brain activation patterns associated with win or loss outcomes had poor to fair reliability.

Twenty-four-hour movement guidelines are reported to correlate with a reduction in the risk of metabolic disease in all age groups. We explored the association between meeting 24-h Movement Guidelines and cardiometabolic syndrome in the general adult population using data from the Korea National Health and Nutrition Examination Survey (KNHANES). This population-based cross-sectional study used data from the KNHANES 2014–2017 and included 2151 adults. Physical activity and sedentary behavior were measured using a three-axis accelerometer. Sleep time was measured using a self-reported questionnaire. Compared with adherence to none of the three guidelines, the odds ratio (OR) for meeting two of the three guidelines were 0.66 (95% confidence interval 0.45–0.98), whereas the OR for meeting all three guidelines was 0.24 (95% CI 0.10–0.59). In the analysis of specific combinations, the group that met the physical activity and sleep time guidelines had a significantly lower risk of cardiometabolic syndrome (OR 0.45, 95% CI 0.21–0.90). Consequently, we suggest that adherence to two or more physical activity guidelines may reduce the risk of cardiometabolic syndrome in Korean adults. Furthermore, meeting all three guidelines is more closely associated with cardiometabolic health owing to their synergistic effects.

Traumatic brain injury (TBI) is a leading cause of morbidity worldwide, for which biomarkers are needed to better understand the underlying pathophysiology. Microvascular injury represents a subset of pathological mechanisms contributing to cognitive dysfunction after TBI, which may also impair subsequent neural repair thereby inhibiting cognitive recovery. Magnetic resonance imaging (MRI)-based measurement of cerebral blood flow (CBF) by arterial spin labeling (ASL) provides an appealing means of assessing microvascular disruption in TBI; however, the relationship between CBF alterations in the early chronic post-TBI setting and cognitive dysfunction as well as subsequent cognitive recovery remain poorly understood. Structural MRI and ASL were performed in 42 TBI subjects 3 months post-injury and 35 matched healthy controls. Neuropsychological testing was performed in each subject, as well as in a subset of TBI patients (n = 33) at 6 and/or 12 months post-injury. TBI and control subject CBF data were compared between groups in a voxel-wise fashion while controlling for the effects of structural atrophy. A region-of-interest approach was then used to compare CBF to clinical and neuropsychological measures within the TBI group in a cross-sectional fashion, as well as to the degree of subsequent cognitive recovery among subjects with follow-up testing. At 3 months post-injury, the TBI group demonstrated lower performance in each cognitive domain (p < 0.05), as well as widespread reductions in gray matter CBF independent of structural atrophy (p < 0.05). Within the TBI group, CBF was moderately correlated with injury severity (r = −0.43; p = 0.009) and executive function (r = 0.43; p = 0.01). In the longitudinal analysis, there was a positive correlation between initial CBF and processing speed recovery (r = 0.43; p = 0.015) independent of age, education level, and initial test score. Early chronic TBI is associated with widespread gray matter CBF deficits, which are correlated with injury severity and cognitive dysfunction. CBF may predict subsequent recovery in some cognitive domains.

Reducing sedentary behavior and increasing physical activity may be important for maintaining good cardiometabolic health. However, many studies have focused on the independent effect of sedentary behavior and physical activity, but it is unclear whether replacing time spent in sedentary behavior with physical activity is beneficial for cardiometabolic health. Therefore, this population-based cross-sectional study aimed to investigate the effect of behavioral transformations between sedentary behavior and level of physical activity on cardiometabolic health in Korean adults using data from the Korea National Health and Nutrition Examination Survey (KNHANES) 2014–2017. The study participants included 2197 adults from the KNHANES. In the partition model, moderate-to-vigorous physical activity (MVPA) was significantly associated with adverse cardiometabolic health, adjusted for potential confounding factors. The odds ratio for adverse cardiometabolic health significantly decreased with the replacement of sedentary behavior and light intensity activity with MVPA in the isotemporal substitution model (p < 0.05). In the models stratified by sex, we observed significant associations between handgrip strength and cardiometabolic health in women (p < 0.001), but not in men. Thus, our findings suggest that replacing sedentary behavior with MVPA may contribute to improved cardiometabolic health.

Sleep deprivation significantly impairs a range of cognitive and brain function, particularly episodic memory and the underlying hippocampal function. However, it remains controversial whether one or two nights of recovery sleep following sleep deprivation fully restores brain and cognitive function. In this study, we used functional magnetic resonance imaging (fMRI) and examined the effects of two consecutive nights (20-hour time-in-bed) of recovery sleep on resting-state hippocampal connectivity and episodic memory deficits following one night of total sleep deprivation (TSD) in 39 healthy adults in a controlled in-laboratory protocol. TSD significantly reduced memory performance in a scene recognition task, impaired hippocampal connectivity to multiple prefrontal and default mode network regions, and disrupted the relationships between memory performance and hippocampal connectivity. Following TSD, two nights of recovery sleep restored hippocampal connectivity to baseline levels, but did not fully restore memory performance nor its associations with hippocampal connectivity. These findings suggest that more than two nights of recovery sleep are needed to fully restore memory function and hippocampal-memory associations after one night of total sleep loss.

To comprehend the volumetric neural connectivity of a brain organoid, it is crucial to monitor the spatiotemporal electrophysiological signals within the organoid, known as intra-organoid signals. However, previous methods risked damaging the three-dimensional (3D) cytoarchitecture of organoids, either through sectioning or inserting rigid needle-like electrodes. Also, the limited numbers of electrodes in fixed positions with non-adjustable electrode shapes were insufficient for examining the complex neural activity throughout the organoid. Herein, we present a magnetically reshapable 3D multi-electrode array (MEA) using direct printing of liquid metals for electrophysiological analysis of brain organoids. The adaptable distribution and the softness of these printed electrodes facilitate the spatiotemporal recording of intra-organoid signals. Furthermore, the unique capability to reshape these soft electrodes within the organoid using magnetic fields allows a single electrode in the MEA to record from multiple points, effectively increasing the recording site density without the need for additional electrodes. Conventional platforms for electrophysiological recording of organoids have limited recording site density. Here, the authors present the magnetically reshapable 3D liquid metal-based electrode array for high-resolution analysis on neural activities of brain organoids.

This paper analyzes low-Earth-orbit (LEO) satellite downlinks when an airborne interference source moves parallel to the satellite trajectory by considering the relative angle differences between the satellites and the interference sources. To make the experimental interference situations more like actual environments, the LEO trajectories are obtained from two-line element set (TLE) data. Airborne interference sources with various altitudes move parallel to the LEO trajectories, and a jamming to signal (J/S) ratio is calculated based on the relative angle differences between the ground station, the LEO satellite, and the interference source. To accurately calculate the J/S ratio, we should apply the sidelobe gain from which the interference signal enters to the ground station antenna. In order to calculate the relative angle difference ψ, the coordinates of the satellite and the interference source are converted from the World Geodetic System 1984 (WGS84) to the ground station-centered east–north-up (ENU) system. The resulting J/S ratio demonstrates that the distance and the relative angle difference ψ between the ground stations, LEO satellite, and airborne interference source appear to be important factors causing changes in the J/S ratio. Among them, the relative angle difference ψ, which determines the sidelobe gain of the ground station antenna, is the most significant factor affecting the J/S ratio variation.

The prospective association of muscular weakness with the risk of all-cause and premature mortality in a general population remains unknown. The aim of this study was to investigate the prospective effects of handgrip strength and muscular weakness on risk for all-cause and premature mortality over 10 years using a large nationwide sample of Korean adults. The study participants included 9229 middle and older adults (4131 males and 5098 females), using data from the Korean Longitudinal Study of Ageing 2006–2016. Muscular strength was measured using handgrip strength. Muscle weakness was defined using the sex-specific handgrip strength index based on the Asian Working Group on Sarcopenia in Older People (AWGSOP). The primary outcome was all-cause and premature mortality assessed based on the death certificate. The hazard ratio (HR) for all-cause mortality was negatively associated with level of handgrip strength independent of potential confounding factors (HR: 2.06, 95% confidence interval [CI]: 1.62–2.63 for lowest quartile vs. highest quartile). When examined using muscle weakness defined using the AWGSOP diagnosis, the mortality was 1.56 times higher in the weak group (HR: 1.56, 95% CI: 1.36–1.78). We also found that risk of premature mortality was observed in the lowest quartile (HR: 2.34, 95% CI: 1.80–3.05) and the muscle weakness group (HR: 1.80, 95% CI: 1.52–2.13) in the fully adjusted model. Our 10-year prospective cohort study showed that handgrip strength and muscle weakness are strongly associated with an increased risk of all-cause and premature mortality in healthy middle-aged and older adults.