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International Journal of Molecular... Dec 2020An action potential (AP) triggers neurotransmitter release from synaptic vesicles (SVs) docking to a specialized release site of presynaptic plasma membrane, the active... (Review)
Review
An action potential (AP) triggers neurotransmitter release from synaptic vesicles (SVs) docking to a specialized release site of presynaptic plasma membrane, the active zone (AZ). The AP simultaneously controls the release site replenishment with SV for sustainable synaptic transmission in response to incoming neuronal signals. Although many studies have suggested that the replenishment time is relatively slow, recent studies exploring high speed resolution have revealed SV dynamics with milliseconds timescale after an AP. Accurate regulation is conferred by proteins sensing Ca entering through voltage-gated Ca channels opened by an AP. This review summarizes how millisecond Ca dynamics activate multiple protein cascades for control of the release site replenishment with release-ready SVs that underlie presynaptic short-term plasticity.
Topics: Animals; Humans; Neuronal Plasticity; Neurotransmitter Agents; Presynaptic Terminals; Synaptic Transmission
PubMed: 33396919
DOI: 10.3390/ijms22010327 -
JAMA Cardiology Oct 2022
Topics: Humans; Mitral Valve; Tachycardia, Paroxysmal; Tachycardia, Supraventricular
PubMed: 36069967
DOI: 10.1001/jamacardio.2022.2902 -
Behavior Research Methods Apr 2022Virtual reality (VR) is a new methodology for behavioral studies. In such studies, the millisecond accuracy and precision of stimulus presentation are critical for data...
Virtual reality (VR) is a new methodology for behavioral studies. In such studies, the millisecond accuracy and precision of stimulus presentation are critical for data replicability. Recently, Python, which is a widely used programming language for scientific research, has contributed to reliable accuracy and precision in experimental control. However, little is known about whether modern VR environments have millisecond accuracy and precision for stimulus presentation, since most standard methods in laboratory studies are not optimized for VR environments. The purpose of this study was to systematically evaluate the accuracy and precision of visual and auditory stimuli generated in modern VR head-mounted displays (HMDs) from HTC and Oculus using Python 2 and 3. We used the newest Python tools for VR and Black Box Toolkit to measure the actual time lag and jitter. The results showed that there was an 18-ms time lag for visual stimulus in both HMDs. For the auditory stimulus, the time lag varied between 40 and 60 ms, depending on the HMD. The jitters of those time lags were 1 ms for visual stimulus and 4 ms for auditory stimulus, which are sufficiently low for general experiments. These time lags were robustly equal, even when auditory and visual stimuli were presented simultaneously. Interestingly, all results were perfectly consistent in both Python 2 and 3 environments. Thus, the present study will help establish a more reliable stimulus control for psychological and neuroscientific research controlled by Python environments.
Topics: Humans; Virtual Reality
PubMed: 34346042
DOI: 10.3758/s13428-021-01663-w -
Ear, Nose, & Throat Journal Feb 2023Fatigue is thought of as a leading cause of iatrogenic accidents. A significant deterioration in qualitative balance function has been shown in sleep deprived...
BACKGROUND
Fatigue is thought of as a leading cause of iatrogenic accidents. A significant deterioration in qualitative balance function has been shown in sleep deprived individuals.
AIM/OBJECTIVES
To quantify the degree to which balance is impaired by sleep deprivation (SD) in post-call medical residents.
METHODS
Medical residents voluntarily underwent computed dynamic posturography (CDP) before and after an on-call night, at an identical time of the day. Order of test performance was random to avoid behavioral learning. Each participant served as his or her own control.
RESULTS
Seventeen residents were enrolled (median age 32years). Average sleeping duration the night before and during the night shift was 6.5 and 1 hour, respectively. The average response times difference between alert and fatigued was 10.15 milliseconds (95% CI: 6.81-13.49 milliseconds), yielding a significantly prolonged response times from 120 milliseconds before to 130 milliseconds after the night shift ( < .001). Comparison of additional measurements of CDP performance did not differ between test conditions.
CONCLUSION
Medical residents are fatigued due to the effect of on-call nights. Sleep deprivation prolongs response times to vestibular stimuli. This finding probably has an effect on execution of manual skills and may reflect a more generalized slowing of responses and overall performance impairment.
SIGNIFICANCE
The vestibular system is susceptible to SD.
Topics: Humans; Male; Female; Adult; Sleep Deprivation; Internship and Residency; Sleep; Sleep Duration; Work Schedule Tolerance; Fatigue
PubMed: 33393818
DOI: 10.1177/0145561320980242 -
Frontiers in Molecular Biosciences 2023Nuclear chromosome compaction is non-random and dynamic. The spatial distance among genomic elements instantly modulates transcription. Visualization of the genome... (Review)
Review
Nuclear chromosome compaction is non-random and dynamic. The spatial distance among genomic elements instantly modulates transcription. Visualization of the genome organization in the cell nucleus is essential to understand nuclear function. In addition to cell type-dependent organization, high-resolution 3D imaging shows heterogeneous compaction of chromatin organization among the same cell type. Questions remain to be answered if these structural variations were the snapshots of dynamic organization at different time points and if they are functionally different. Live-cell imaging has provided unique insights into dynamic genome organization at short (milliseconds) and long (hours) time scales. The recent development of CRISPR-based imaging opened windows for studying dynamic chromatin organization in single cells in real time. Here we highlight these CRISPR-based imaging techniques and discuss their advances and challenges as a powerful live-cell imaging method that poses high potential to generate paradigm-shifting discoveries and reveal functional implications of dynamic chromatin organization.
PubMed: 37065447
DOI: 10.3389/fmolb.2023.1173545 -
ELife Aug 2021Human standing balance relies on self-motion estimates that are used by the nervous system to detect unexpected movements and enable corrective responses and adaptations...
Human standing balance relies on self-motion estimates that are used by the nervous system to detect unexpected movements and enable corrective responses and adaptations in control. These estimates must accommodate for inherent delays in sensory and motor pathways. Here, we used a robotic system to simulate human standing about the ankles in the anteroposterior direction and impose sensorimotor delays into the control of balance. Imposed delays destabilized standing, but through training, participants adapted and re-learned to balance with the delays. Before training, imposed delays attenuated vestibular contributions to balance and triggered perceptions of unexpected standing motion, suggesting increased uncertainty in the internal self-motion estimates. After training, vestibular contributions partially returned to baseline levels and larger delays were needed to evoke perceptions of unexpected standing motion. Through learning, the nervous system accommodates balance sensorimotor delays by causally linking whole-body sensory feedback (initially interpreted as imposed motion) to self-generated balance motor commands.
Topics: Adult; Computer Simulation; Feedback, Sensory; Female; Humans; Learning; Male; Motion; Postural Balance; Posture; Robotics; Vestibule, Labyrinth; Young Adult
PubMed: 34374648
DOI: 10.7554/eLife.65085 -
Journal of Magnetic Resonance (San... Sep 2022We review recent efforts to develop and apply an experimental approach to the structural characterization of transient intermediate states in biomolecular processes that... (Review)
Review
We review recent efforts to develop and apply an experimental approach to the structural characterization of transient intermediate states in biomolecular processes that involve large changes in molecular conformation or assembly state. This approach depends on solid state nuclear magnetic resonance (ssNMR) measurements that are performed at very low temperatures, typically 25-30 K, with signal enhancements from dynamic nuclear polarization (DNP). This approach also involves novel technology for initiating the process of interest, either by rapid mixing of two solutions or by a rapid inverse temperature jump, and for rapid freezing to trap intermediate states. Initiation by rapid mixing or an inverse temperature jump can be accomplished in approximately-one millisecond. Freezing can be accomplished in approximately 100 microseconds. Thus, millisecond time resolution can be achieved. Recent applications to the process by which the biologically essential calcium sensor protein calmodulin forms a complex with one of its target proteins and the process by which the bee venom peptide melittin converts from an unstructured monomeric state to a helical, tetrameric state after a rapid change in pH or temperature are described briefly. Future applications of millisecond time-resolved ssNMR are also discussed briefly.
Topics: Magnetic Resonance Spectroscopy; Molecular Conformation; Nuclear Magnetic Resonance, Biomolecular; Peptides; Proteins
PubMed: 35998398
DOI: 10.1016/j.jmr.2022.107285 -
IScience Sep 2021Neurons in the visual cortex quickly adapt to constant input, which should lead to perceptual fading within few tens of milliseconds. However, perceptual fading is...
Neurons in the visual cortex quickly adapt to constant input, which should lead to perceptual fading within few tens of milliseconds. However, perceptual fading is rarely observed in everyday perception, possibly because eye movements refresh retinal input. Recently, it has been suggested that amplitudes of large saccadic eye movements are scaled to maximally decorrelate presaccadic and postsaccadic inputs and thus to annul perceptual fading. However, this argument builds on the assumption that adaptation within naturally brief fixation durations is strong enough to survive any visually disruptive saccade and affect perception. We tested this assumption by measuring the effect of luminance adaptation on postsaccadic contrast perception. We found that postsaccadic contrast perception was affected by presaccadic luminance adaptation during brief periods of fixation. This adaptation effect emerges within 100 milliseconds and persists over seconds. These results indicate that adaptation during natural fixation periods can affect perception even after visually disruptive saccades.
PubMed: 34485868
DOI: 10.1016/j.isci.2021.102986 -
Lasers in Surgery and Medicine Jan 2021To evaluate the efficacy of an enhanced pulsed dye laser (PDL) for treatment of facial-dyschromia.
BACKGROUND AND OBJECTIVES
To evaluate the efficacy of an enhanced pulsed dye laser (PDL) for treatment of facial-dyschromia.
STUDY DESIGN/MATERIALS AND METHODS
Thirteen patients were enrolled in the study. Nine patients were female, four were male, with a mean age of 61 years. All patients presented with either facial telangiectasia, rosacea, pigment, or a combination thereof. At the initial evaluation, test spots were performed to determine the subject's response to selected treatment parameters. In the study, the enhanced 595 nm PDL deployed a spot size range of 5-12 mm with fluences ranging from 8 to 18 J/cm . Pulse duration was 10 milliseconds. Enhancements in this device included the option for contact or cryogen spray cooling, increased maximum pulse energy, increased repetition rate, option for addition of radiofrequency (RF), an option for a 15 mm spot size, and longer dye life. The smaller spots were used only for focal low contrast pigmented lesions that persisted after overall facial treatment with the larger spot. Smaller fluences were applied for general rejuvenation with the 12 mm spot (mean ~9 J/cm ). Sapphire contact cooling was applied at 10°C. A smaller area of the skin was reserved (typically pre-auricular area) for addition of RF energy just before the pulse (40-70 J/cm ) over 100 milliseconds with a 20 milliseconds delay between the end of the RF pulse and beginning of the laser pulse. The minimum fluence that achieved vessel closure/vessel bluing and/or slight immediate pigment darkening was applied based on test spots performed just before treatment to the entire face. Determinations of improvement were made by evaluation of photographs with standard settings using polarized and nonpolarized images. Up to three treatments were performed approximately 1 month apart with follow-up visits 1 and 3 months after the final treatment.
RESULTS
Evaluation by a panel of blind observers determined a mean clearance of at least 50% in all lesions, while 77% of lesions had 50-75% clearance, and 23% of lesions had 76-100% clearance. Pain was approximately 4/10. Subjective lesion improvement and satisfaction rates were 3 out of 4 and 3.6 out 4, respectively.
CONCLUSION
An enhanced PDL is effective in one pass treatments for facial rejuvenation with considerably less operative time than previous commercially available systems. A second pass applied to focal challenging lesions results in even more improvement, in a single treatment session. Lasers Surg. Med. © 2020 Wiley Periodicals LLC.
Topics: Female; Humans; Laser Therapy; Lasers, Dye; Male; Middle Aged; Pigmentation Disorders; Rejuvenation; Telangiectasis; Treatment Outcome
PubMed: 32779273
DOI: 10.1002/lsm.23309 -
Nanomaterials (Basel, Switzerland) Aug 2023A human body monitoring system remains a significant focus, and to address the challenges in wearable sensors, a nanotechnology-enhanced strategy is proposed for...
A human body monitoring system remains a significant focus, and to address the challenges in wearable sensors, a nanotechnology-enhanced strategy is proposed for designing stretchable metal-organic polymer nanocomposites. The nanocomposite comprises reduced graphene oxide (rGO) and in-situ generated silver nanoparticles (AgNPs) within elastic electrospun polystyrene-butadiene-polystyrene (SBS) fibers. The resulting Sandwich Structure Piezoresistive Woven Nanofabric (SSPWN) is a tactile-sensitive wearable sensor with remarkable performance. It exhibits a rapid response time (less than three milliseconds) and high reproducible stability over 5500 cycles. The nanocomposite also demonstrates exceptional thermal stability due to effective connections between rGO and AgNPs, making it suitable for wearable electronic applications. Furthermore, the SSPWN is successfully applied to human motion monitoring, including various areas of the hand and RGB sensing shoes for foot motion monitoring. This nanotechnology-enhanced strategy shows promising potential for intelligent healthcare, health monitoring, gait detection, and analysis, offering exciting prospects for future wearable electronic products.
PubMed: 37630960
DOI: 10.3390/nano13162375