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NeuroImage. Clinical 2024Magnetoencephalography (MEG) is a non-invasive technique that can precisely capture the dynamic spatiotemporal patterns of the brain by measuring the magnetic fields... (Review)
Review
Magnetoencephalography (MEG) is a non-invasive technique that can precisely capture the dynamic spatiotemporal patterns of the brain by measuring the magnetic fields arising from neuronal activity along the order of milliseconds. Observations of brain dynamics have been used in cognitive neuroscience, the diagnosis of neurological diseases, and the brain-computer interface (BCI). In this study, we outline the basic principle, signal processing, and source localization of MEG, and describe its clinical applications for cognitive assessment, the diagnoses of neurological diseases and mental disorders, preoperative evaluation, and the BCI. This review not only provides an overall perspective of MEG, ranging from practical techniques to clinical applications, but also enhances the prevalent understanding of neural mechanisms. The use of MEG is expected to lead to significant breakthroughs in neuroscience.
Topics: Magnetoencephalography; Humans; Brain; Signal Processing, Computer-Assisted; Brain-Computer Interfaces; Brain Mapping; Nervous System Diseases
PubMed: 38653131
DOI: 10.1016/j.nicl.2024.103608 -
Vision (Basel, Switzerland) Apr 2024Myopia management contact lenses have been shown to successfully decrease the rate of eye elongation in children by changing the peripheral refractive profile of the...
BACKGROUND
Myopia management contact lenses have been shown to successfully decrease the rate of eye elongation in children by changing the peripheral refractive profile of the retina. Despite the efforts of the scientific community, the retinal response mechanism to defocus is still unknown. The purpose of this study was to evaluate the local electrophysiological response of the retina with a myopia control contact lens (CL) compared to a single-vision CL of the same material.
METHODS
The retinal electrical activity and peripheral refraction of 16 eyes (16 subjects, 27.5 ± 5.7 years, 13 females and 3 males) with myopia between -0.75 D and -6.00 D (astigmatism < 1.00 D) were assessed with two CLs (Filcon 5B): a single-vision (SV) CL and an extended-depth-of-focus (EDOF) CL used for myopia management. The peripheral refraction was assessed with an open-field WAM-5500 auto-refractometer/keratometer in four meridians separated by 45° at 2.50 m distance. The global-flash multifocal electroretinogram (gf-mfERG) was recorded with the Reti-port/scan21 (Roland Consult) using a stimulus of 61 hexagons. The implicit time (in milliseconds) and response density (RD, in nV/deg) of the direct (DC) and induced (IC) components were used for comparison between lenses in physiological pupil conditions.
RESULTS
Although the EDOF decreased both the HCVA and the LCVA (one and two lines, respectively; < 0.003), it still allowed a good VA. The EDOF lens induced a myopic shift in most retinal areas, with a higher and statistically significant effect on the nasal retina. No differences in the implicit times of the DC and IC components were observed between SV and EDOF. Compared with the SV, the EDOF lens showed a higher RD in the IC component in the foveal region ( = 0.032). In the remaining retinal areas, the EDOF evoked lower, non-statistically significant RD in both the DC and IC components.
CONCLUSIONS
The EDOF myopia control CL enhanced the response of the inner layers of the fovea. This might suggest that, besides other mechanisms potentially involved, the central foveal retinal activity might be involved in the mechanism of myopia control with these lenses.
PubMed: 38651440
DOI: 10.3390/vision8020019 -
BioRxiv : the Preprint Server For... Apr 2024Memory brain states may influence how we experience an event. Memory encoding and retrieval constitute neurally dissociable brain states that individuals can selectively...
Memory brain states may influence how we experience an event. Memory encoding and retrieval constitute neurally dissociable brain states that individuals can selectively engage based on top-down goals. To the extent that memory states linger in time - as suggested by prior behavioral work - memory states may influence not only the current experience, but also subsequent stimuli and judgments. Thus lingering memory states may have broad influences on cognition, yet this account has not been directly tested utilizing neural measures of memory states. Here we address this gap by testing the hypothesis that memory brain states are modulated by memory judgments, and that these brain states persist for several hundred milliseconds. We recorded scalp electroencephalography (EEG) while participants completed a recognition memory task. We used an independently validated multivariate mnemonic state classifier to assess memory state engagement. We replicate prior behavioral findings; however, our neural findings run counter to the predictions made on the basis of the behavioral data. Surprisingly, we find that prior responses modulate current memory state engagement on the basis of response congruency. That is, we find strong engagement of the retrieval state on incongruent trials - when a target is preceded by a correct rejection of a lure and when a lure is preceded by successful recognition of a target. These findings indicate that cortical brain states are influenced by prior judgments and suggest that a non-mnemonic, internal attention state may be recruited to in the face of changing demands in a dynamic environment.
PubMed: 38645245
DOI: 10.1101/2024.04.05.588245 -
Journal of Colloid and Interface Science Aug 2024Naturally extracted polysaccharides, such as guar gum, are promising candidates for environmentally friendly flotation reagents. It is hypothesized that the kinetics of...
HYPOTHESIS
Naturally extracted polysaccharides, such as guar gum, are promising candidates for environmentally friendly flotation reagents. It is hypothesized that the kinetics of collision of sub- to millimeter gas bubbles with a hydrophobic graphite surface, and the stability of thin liquid film formed between the bubble and surface is affected by an adsorbed layer of guar gum.
EXPERIMENTS
A combination of gravimetric (quartz crystal microbalance with dissipation) and imaging (atomic force microscopy) techniques was used to investigate the adsorption of guar gum on graphite surface, while high-speed camera imaging allowed for direct observation of the bubble collision process with guar gum-modified graphite surfaces with millisecond resolution.
FINDINGS
Atomic force microscope topography images revealed a guar gum concentration-dependent interconnected network of guar gum molecules adsorbed at graphite surface. These adsorbed molecules at low surface coverage, changed the wettability of the graphite surface, resulting in a film drainage time longer by an order of magnitude, while at higher surface coverage successfully prevented bubble attachment to the graphite surface. Most importantly, the adsorbed layer changed the strength of the bubble's bouncing off the graphite surface. This enhanced bubble bouncing can be correlated with the film drainage time and used to predict a successful bubble-particle attachment.
PubMed: 38640658
DOI: 10.1016/j.jcis.2024.04.073 -
PloS One 2024The Internet of Things (IoT) is gradually changing the way teaching and learning take place in on-campus programs. In particular, face capture services improve student...
The Internet of Things (IoT) is gradually changing the way teaching and learning take place in on-campus programs. In particular, face capture services improve student concentration to create an efficient classroom atmosphere by using face recognition algorithms that support end devices. However, reducing response latency and executing face analysis services effectively in real-time is still challenging. For this reason, this paper proposed a pedagogical model of face recognition for IoT devices based on edge computing (TFREC). Specifically, this research first proposed an IoT service-based face capture algorithm to optimize the accuracy of face recognition. In addition, the service deployment method based on edge computing is proposed in this paper to obtain the best deployment strategy and reduce the latency of the algorithm. Finally, the comparative experimental results demonstrate that TFREC has 98.3% accuracy in face recognition and 72 milliseconds in terms of service response time. This research is significant for advancing the optimization of teaching methods in school-based courses, meanwhile, providing beneficial insights for the application of face recognition and edge computing in the field of education.
Topics: Humans; Internet of Things; Internet; Educational Status; Computers; Technology
PubMed: 38635843
DOI: 10.1371/journal.pone.0298534 -
PloS One 2024Wireless Sensor Networks (WSNs) consist of small, multifunctional nodes distributed across various locations to monitor and record parameters. These nodes store data and...
Wireless Sensor Networks (WSNs) consist of small, multifunctional nodes distributed across various locations to monitor and record parameters. These nodes store data and transmit signals for further processing, forming a crucial topic of study. Monitoring the network's status in WSN applications using clustering systems is essential. Collaboration among sensors from various domains enhances the precision of localised information reporting. However, nodes closer to the data sink consume more energy, leading to hotspot challenges. To address these challenges, this research employs clustering and optimised routing techniques. The aggregation of information involves creating clusters, further divided into sub-clusters. Each cluster includes a Cluster Head (CH) or Sensor Nodes (SN) without a CH. Clustering inherently optimises CHs' capabilities, enhances network activity, and establishes a systematic network topology. This model accommodates both multi-hop and single-hop systems. This research focuses on selecting CHs using a Genetic Algorithm (GA), considering various factors. While GA possesses strong exploration capabilities, it requires effective management. This research uses Prairie Dog Optimization (PDO) to overcome this challenge. The proposed Hotspot Mitigated Prairie with Genetic Algorithm (HM-PGA) significantly improves WSN performance, particularly in hotspot avoidance. With HM-PGA, it achieves a network lifetime of 20913 milliseconds and 310 joules of remaining energy. Comparative analysis with existing techniques demonstrates the superiority of the proposed approach.
Topics: Animals; Cluster Analysis; Sciuridae; Algorithms
PubMed: 38630730
DOI: 10.1371/journal.pone.0298756 -
Sports Medicine - Open Apr 2024Practicing sports during childhood and adolescence provides benefits to cardiac autonomic modulation (CAM) at these stages of life. However, it is not known whether...
BACKGROUND
Practicing sports during childhood and adolescence provides benefits to cardiac autonomic modulation (CAM) at these stages of life. However, it is not known whether these benefits to CAM persist into adulthood. Therefore, the objective of this study was to analyze the association of early sports practice (sports practice in childhood and/or adolescence) with CAM in adult life, regardless of habitual moderate-to-vigorous PA.
METHODS
The sample of the present study consisted of 242 adults (141 women and 101 men; age: 41.99 ± 16.24). The assessment of CAM was performed using heart rate variability indices. Sports practice in childhood and adolescence was assessed using a questionnaire. The intensity of physical activity was assessed using accelerometry. To analyze the association between previous sports practice (childhood and/or adolescence) and CAM, the Generalized Linear Model was adopted, considering CAM indices as continuous variables and early sports practice as a 3-fold factor (no sports practice; sports practice in childhood or adolescence; and sports practice in both childhood and adolescence) adjusted by sex, age, socioeconomic condition, and moderate to vigorous PA.
RESULTS
Sports practice in childhood was associated with the average standard deviation of all normal RR intervals expressed in milliseconds (SDNN): β = 5.89; 95%CI: 0.25;11.52, and the standard deviation of the long-term intervals between consecutive heartbeats (SD2): β = 7.63; 95%CI:1.04; 14.23 indices. Sports practice in adolescence was associated in adulthood with the SD2 index: β = 7.37; 95%CI: 0.71;14.04. Sports practice in at least one of the periods (childhood or adolescence) was significantly associated with the square root of the mean square of the differences between adjacent normal RR intervals for a period of time expressed in milliseconds (RMSSD) (β = 8.86; 95%CI = 0.71;17.01), and the standard deviation of the instantaneous beat to beat variability (SD1) (β = 6.21; 95%CI = 0.45;11.97). Sports practice at both stages of life was significantly associated with better SDNN (β = 7.70; 95%CI = 1.16;14.23) and SD2 (β = 10.18; 95%CI = 2.51;17.85).
CONCLUSION
Early sports practice was associated with better CAM in adulthood, independently of the current physical activity level. Based on these findings, sports practice is encouraged from childhood and adolescence, for benefits to CAM in adult life.
PubMed: 38625654
DOI: 10.1186/s40798-024-00707-7 -
Nature Communications Apr 2024Proteins are molecular machines and to understand how they work, we need to understand how they move. New pump-probe time-resolved X-ray diffraction methods open up ways...
Proteins are molecular machines and to understand how they work, we need to understand how they move. New pump-probe time-resolved X-ray diffraction methods open up ways to initiate and observe protein motions with atomistic detail in crystals on biologically relevant timescales. However, practical limitations of these experiments demands parallel development of effective molecular dynamics approaches to accelerate progress and extract meaning. Here, we establish robust and accurate methods for simulating dynamics in protein crystals, a nontrivial process requiring careful attention to equilibration, environmental composition, and choice of force fields. With more than seven milliseconds of sampling of a single chain, we identify critical factors controlling agreement between simulation and experiments and show that simulated motions recapitulate ligand-induced conformational changes. This work enables a virtuous cycle between simulation and experiments for visualizing and understanding the basic functional motions of proteins.
Topics: Proteins; Molecular Dynamics Simulation; X-Ray Diffraction; Protein Conformation
PubMed: 38622111
DOI: 10.1038/s41467-024-47473-4 -
Clinical Cardiology Apr 2024We analyzed the influence of the QRS duration (QRSd) to LV end-diastolic volume (LVEDV) ratio on cardiac resynchronization therapy (CRT) outcomes in heart failure...
BACKGROUND
We analyzed the influence of the QRS duration (QRSd) to LV end-diastolic volume (LVEDV) ratio on cardiac resynchronization therapy (CRT) outcomes in heart failure patients classified as III/IV per the New York Heart Association (NYHA) and with small body size.
HYPOTHESIS
We proposed the hypothesis that the QRSd/LV size ratio is a better index of the CRT substrate.
METHODS
We enrolled 114 patients with advanced heart failure (NYHA class III/IV, and LV ejection fraction >35%) who received a CRT device, including those with left bundle branch block (LBBB) and QRSd ≥120 milliseconds (n = 60), non-LBBB and QRSd ≥150 milliseconds (n = 30) and non-LBBB and QRSd of 120-149 milliseconds (n = 24).
RESULTS
Over a mean follow-up period of 65 ± 58 months, the incidence of the primary endpoint, a composite of all-cause death and hospitalization for heart failure, showed no significant intergroup difference (43.3% vs. 50.0% vs. 37.5%, respectively, p = .72). Similarly, among 104 patients with QRSd/LVEDV ≥ 0.67 (n = 54) and QRSd/LVEDV < 0.67 (n = 52), no significant differences were observed in the incidence of the primary endpoint (35.1% vs. 51.9%, p = .49). Nevertheless, patients with QRSd/LVEDV ≥ 0.67 showed better survival than those with QRSd/LVEDV < 0.67 (14.8% vs. 34.6%, p = .0024).
CONCLUSION
Advanced HF patients with a higher QRSd/LVEDV ratio showed better survival in this small-body-size population. Thus, the risk is concentrated among those with a larger QRSd, and patients with a relatively smaller left ventricular size appeared to benefit from CRT.
Topics: Humans; Cardiac Resynchronization Therapy; Japan; Cardiac Resynchronization Therapy Devices; Heart; Bundle-Branch Block; Heart Failure
PubMed: 38619004
DOI: 10.1002/clc.24267 -
Materials (Basel, Switzerland) Apr 2024To address the issue of the lack of red light in traditional Ce: YAG-encapsulated blue LED white light systems, we utilized spark plasma sintering (SPS) to prepare...
To address the issue of the lack of red light in traditional Ce: YAG-encapsulated blue LED white light systems, we utilized spark plasma sintering (SPS) to prepare spinel-based Cr-doped red phosphor ceramics. Through phase and spectral analysis, the SPS-sintered ZnAlO: 0.5%Cr phosphor ceramic exhibits good density, and Cr is incorporated into [AlO] octahedra as a red emitting center. We analyzed the reasons behind the narrow-band emission and millisecond-level lifetime of ZAO: 0.5%Cr, attributing it to the four-quadrupole interaction mechanism as determined through concentration quenching modeling. Additionally, we evaluated the thermal conductivity and thermal quenching performance of the ceramic. The weak electron-phonon coupling (EPC) effects and emission from antisite defects at 699 nm provide positive assistance in thermal quenching. At a high temperature of 150 °C, the thermal conductivity reaches up to 14 W·m·K, and the 687 nm PL intensity is maintained at around 70% of room temperature. Furthermore, the internal quantum efficiency (IQE) of ZAO: 0.5%Cr phosphor ceramic can reach 78%. When encapsulated with Ce: YAG for a 450 nm blue LED, it compensates for the lack of red light, adjusts the color temperature, and improves the color rendering index (R9). This provides valuable insights for the study of white light emitting diodes (WLEDs).
PubMed: 38612124
DOI: 10.3390/ma17071610