39,808 results match your criteria gating


The setting of heartbeat acceptance windows on gated myocardial perfusion single-photon emission computed tomography using CZT camera: effect of left ventricular functional parameters in patients with arrhythmia.

Nucl Med Commun 2021 Apr 12. Epub 2021 Apr 12.

Department of Central Radiology, Gifu Prefectural Gero Hot Spring Hospital, Gero Department of Radiological Technology, Kurashiki Central Hospital, Kurashiki Department of Quantum Medical Technology, Institute of Medical, Pharmaceutical and Health Sciences, Kanazawa University, Kanazawa, Japan.

Objectives: Consistently variable with several peaks in heart rate histogram (e.g. bigeminy and trigeminy) is one of the arrhythmia types. Read More

View Article and Full-Text PDF

An arginine residue in the outer segment of hASIC1a TM1 affects both proton affinity and channel desensitization.

J Gen Physiol 2021 May;153(5)

Department of Basic Sciences, Tsinghua University School of Medicine, Beijing, China.

Acid-sensing ion channels (ASICs) respond to changes in pH in the central and peripheral nervous systems and participate in synaptic plasticity and pain perception. Understanding the proton-mediated gating mechanism remains elusive despite the of their structures in various conformational states. We report here that R64, an arginine located in the outer segment of the first transmembrane domain of all three isoforms of mammalian ASICs, markedly impacts the apparent proton affinity of activation and the degree of desensitization from the open and preopen states. Read More

View Article and Full-Text PDF

Profound gating error and flattened time-volume curve from inefficient triggering from improper setting of ECG leads in myocardial perfusion SPECT.

J Nucl Cardiol 2021 Apr 13. Epub 2021 Apr 13.

Department of Nuclear Medicine, Taleghani Educational Hospital, School of Medicine, Shahid Beheshti University of Medical Sciences, Yaman St., Velenjak, Tehran, 1985711151, Iran.

View Article and Full-Text PDF

Does pericentral mu-rhythm "power" corticomotor excitability? - a matter of EEG perspective.

Brain Stimul 2021 Apr 10. Epub 2021 Apr 10.

Danish Research Centre for Magnetic Resonance, Centre for Functional and Diagnostic Imaging and Research, Copenhagen University Hospital, Amager and Hvidovre, Hvidovre, Denmark; Department of Neurology, Copenhagen University Hospital Bispebjerg, Copenhagen, Denmark; Institute for Clinical Medicine, Faculty of Medical and Health Sciences, University of Copenhagen, Copenhagen, Denmark.

Background: Electroencephalography (EEG) and single-pulse transcranial magnetic stimulation (spTMS) of the primary motor hand area (M1-HAND) have been combined to explore whether the instantaneous expression of pericentral mu-rhythm drives fluctuations in corticomotor excitability, but this line of research has yielded diverging results.

Objectives: To re-assess the relationship between the mu-rhythm power expressed in left pericentral cortex and the amplitude of motor potentials (MEP) evoked with spTMS in left M1-HAND.

Methods: 15 non-preselected healthy young participants received spTMS to the motor hot spot of left M1-HAND. Read More

View Article and Full-Text PDF

Hunger-promoting AgRP neurons trigger an astrocyte-mediated feed-forward auto-activation loop in mice.

J Clin Invest 2021 Apr 13. Epub 2021 Apr 13.

Department of Comparative Medicine, Yale University School of Medicine, New Haven, United States of America.

Synaptic plasticity is identified as innate to hypothalamic feeding circuits in their adaptation to the changing metabolic milieu in control of feeding and obesity. However, less is known about the regulatory principles of the dynamic changes of AgRP perikarya, a crucial region of the neuron gating excitation, and hence, feeding. Here we show that AgRP neurons activated either by food deprivation, ghrelin or chemogenetics decreased their own inhibitory tone while triggering mitochondrial adaptations in neighboring astrocytes. Read More

View Article and Full-Text PDF

Extracellular cap domain is an essential component of the TRPV1 gating mechanism.

Nat Commun 2021 04 12;12(1):2154. Epub 2021 Apr 12.

Department of Biochemistry and Molecular Biophysics, Columbia University, New York, NY, USA.

Transient receptor potential (TRP) channels are polymodal molecular sensors involved in numerous physiological processes and implicated in a variety of human diseases. Several structures of the founding member of the TRP channel family, TRPV1, are available, all of which were determined for the protein missing the N- and C-termini and the extracellular S5-P-loop. Here, we present structures of the full-length thirteen-lined ground squirrel TRPV1 solved by cryo-EM. Read More

View Article and Full-Text PDF

A Light-Operated Molecular Cable Car for Gated Ion Transport.

Angew Chem Int Ed Engl 2021 Apr 11. Epub 2021 Apr 11.

Key Labs for Advanced Materials, East China University of Science and Technology, CHINA.

Inspired by the nontrivial and controlled movements of molecular machines, we report an azobenzene-based molecular shuttle PR2 , which can perform light-gated ion transport across lipid membranes. The amphiphilicity and membrane-spanned molecular length enable PR2 to insert into the bilayer membrane and efficiently ferry K + (EC 50 = 4.1 µM) through the thermally driven stochastic shuttle motion of the crown ether ring along the axle. Read More

View Article and Full-Text PDF

Combining rescanning and gating for a time-efficient treatment of mobile tumors using pencil beam scanning proton therapy.

Radiother Oncol 2021 Apr 8. Epub 2021 Apr 8.

Center for Proton Therapy, Paul Scherrer Institute (PSI), 5232 Villigen PSI, Switzerland. Electronic address:

Background And Purpose: Respiratory motion during proton therapy can severely degrade dose distributions, particularly due to interplay effects when using pencil beam scanning. Combined rescanning and gating treatments for moving tumors mitigates dose degradation, but at the cost of increased treatment delivery time. The objective of this study was to identify the time efficiency of these dose degradation-motion mitigation strategies for different range of motions. Read More

View Article and Full-Text PDF

Neuropsychological effect of working memory capacity on mental rotation under hypoxia environment.

Int J Psychophysiol 2021 Apr 8. Epub 2021 Apr 8.

Key Laboratory of Brain, Cognition and Education Sciences, Ministry of Education, School of Psychology, Center for Studies of Psychological Application, Guangdong Key Laboratory of Mental Health and Cognitive Science, South China Normal University, China; Plateau Brain Science Research Center, South China Normal University/Tibet University, China. Electronic address:

High-altitude exposure induces the decline of spatial manipulation such as mental rotation which is limited by working memory capacity, but the underlying neuropsychological effect remains to be identified. We evaluated the mental rotation task and the contralateral delay activity (CDA) task under hypoxia environment using the event-related potential. When compared with the controls, the behavior response was slowed on two tasks in the high-altitude group. Read More

View Article and Full-Text PDF

Rats with elevated genetic risk for metabolic syndrome exhibit cognitive deficiencies when young.

Physiol Behav 2021 Apr 7:113417. Epub 2021 Apr 7.

Centre for Interdisciplinary Brain Research, Department of Psychology, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland; Faculty of Sport and Health Sciences, University of Jyväskylä, P.O. Box 35, FI-40014 University of Jyväskylä, Finland.

Metabolic syndrome (MetS) is a known risk factor for cognitive decline. Using polygenic rat models selectively bred for high and low intrinsic exercise capacity and simultaneously modelling as low and high innate risk factor for MetS respectively, we have previously shown that adult animals with lower exercise capacity/higher MetS risk perform poorly in tasks requiring flexible cognition. However, it is not known whether these deficits in cognition are present already at young age. Read More

View Article and Full-Text PDF

Sound therapy can modulate the functional connectivity of the auditory network.

Prog Neuropsychopharmacol Biol Psychiatry 2021 Apr 7;110:110323. Epub 2021 Apr 7.

Department of Radiology, Beijing Friendship Hospital, Capital Medical University, Beijing 100050, China. Electronic address:

The functional connectivity of the auditory network is considered to be important in the development of tinnitus. We hypothesized that sound therapy, as a commonly used effective treatment for tinnitus, can modulate the functional connectivity of the auditory network. In this prospective observational study, we recruited 27 tinnitus patients who had undergone 12 weeks of sound therapy and 27 matched healthy controls. Read More

View Article and Full-Text PDF

Altered acoustic startle, prepulse facilitation, and object recognition memory produced by corticosterone withdrawal in male rats.

Behav Brain Res 2021 Apr 6:113291. Epub 2021 Apr 6.

Division of Medical Sciences, University of Victoria, Victoria, BC, V8W 2Y2, Canada.

The symptoms of human depression often include cognitive deficits. However, cognition is not frequently included in the behavioral assessments conducted in preclinical models of depression. For example, it is well known that repeated corticosterone (CORT) injections in rodents produce depression-like behavior as measured by the forced swim test, sucrose preference test, and tail suspension test, but the cognitive impairments produced by repeated CORT have not been thoroughly examined. Read More

View Article and Full-Text PDF

Differential white blood cell counts in rabbits: a comparison of the Advia 2120 and a manual method.

J Vet Diagn Invest 2021 Apr 9:10406387211007877. Epub 2021 Apr 9.

Easter Bush Pathology, Royal (Dick) School of Veterinary Studies and The Roslin Institute, University of Edinburgh, Roslin, UK.

We evaluated the performance of the Advia 2120 (Siemens) differential leukocyte count (A-Diff) compared to the manual method (M-Diff) in rabbits. EDTA-anticoagulated blood samples collected for diagnostic purposes were analyzed within 6 h of collection. The M-Diff was performed blindly by 2 observers on blood smears by counting 200 cells. Read More

View Article and Full-Text PDF

Pollen PCP-B peptides unlock a stigma peptide-receptor kinase gating mechanism for pollination.

Science 2021 04;372(6538):171-175

School of Life Sciences, East China Normal University, Shanghai, China.

Sexual reproduction in angiosperms relies on precise communications between the pollen and pistil. The molecular mechanisms underlying these communications remain elusive. We established that in , a stigmatic gatekeeper, the ANJEA-FERONIA (ANJ-FER) receptor kinase complex, perceives the RAPID ALKALINIZATION FACTOR peptides RALF23 and RALF33 to induce reactive oxygen species (ROS) production in the stigma papillae, whereas pollination reduces stigmatic ROS, allowing pollen hydration. Read More

View Article and Full-Text PDF

A surface charge governed nanofluidic diode based on a single polydimethylsiloxane (PDMS) nanochannel.

Authors:
Jun Li Dongqing Li

J Colloid Interface Sci 2021 Mar 24;596:54-63. Epub 2021 Mar 24.

Department of Mechanical and Mechatronics Engineering, University of Waterloo, Waterloo, Ontario N2L 3G1, Canada. Electronic address:

Hypothesis: Nanofluidic diodes have attracted intense attention recently. Commonly used materials to design these devices are membrane-based short nanopores and aligned Carbon nanotube bundles. It is highly desirable and very challenging to develop a nanofluidic diode based on a single PDMS nanochannel which is easier to be introduced into an integrated electronic system on a chip. Read More

View Article and Full-Text PDF

Orientational Jahn-Teller Isomerism in the Dark-Stable State of Nature's Water Oxidase.

Angew Chem Int Ed Engl 2021 Apr 8. Epub 2021 Apr 8.

Max-Planck-Institut für Kohlenforschung, Molecular Theory and Spectroscopy, Kaiser-Wilhelm-Platz 1, 45470, Muelheim an der Ruhr, GERMANY.

The tetramanganese-calcium cluster of the oxygen evolving complex of photosystem II adopts electronically and magnetically distinct but interconvertible valence isomeric forms in its first light-driven oxidized catalytic state, S 2 . This bistability is implicated in gating the final catalytic states preceding O-O bond formation, but it is unknown how the biological system enables its emergence and controls its effect. Here we show that the Mn 4 CaO 5 cluster in the resting (dark-stable) S 1 state adopts orientational Jahn-Teller isomeric forms arising from a directional change in electronic configuration of the "dangler" Mn(III) ion. Read More

View Article and Full-Text PDF

High-Resolution Structures of K Channels.

Authors:
Qiu-Xing Jiang

Handb Exp Pharmacol 2021 Apr 8. Epub 2021 Apr 8.

Laboratory of Molecular Physiology and Biophysics and the Cryo-EM Center, Hauptmann-Woodward Medical Research Institute, Buffalo, NY, USA.

Potassium channels are present in every living cell and essential to setting up a stable, non-zero transmembrane electrostatic potential which manifests the off-equilibrium livelihood of the cell. They are involved in other cellular activities and regulation, such as the controlled release of hormones, the activation of T-cells for immune response, the firing of action potential in muscle cells and neurons, etc. Pharmacological reagents targeting potassium channels are important for treating various human diseases linked to dysfunction of the channels. Read More

View Article and Full-Text PDF

Review of MR-Guided Radiotherapy for Esophageal Cancer.

Front Oncol 2021 22;11:628009. Epub 2021 Mar 22.

Department of Radiation Oncology, University Medical Center Utrecht, Utrecht University, Utrecht, Netherlands.

In this review, we outline the potential benefits and the future role of MRI and MR-guided radiotherapy (MRgRT) in the management of esophageal cancer. Although not currently used in most clinical practice settings, MRI is a useful non-invasive imaging modality that provides excellent soft tissue contrast and the ability to visualize cancer physiology. Chemoradiation therapy with or without surgery is essential for the management of locally advanced esophageal cancer. Read More

View Article and Full-Text PDF

A Heart Failure-Associated Splice Variant Leads to a Reduction in Sodium Current Through Coupled-Gating With the Wild-Type Channel.

Front Physiol 2021 22;12:661429. Epub 2021 Mar 22.

Department of Physiology and Cell Biology, Frick Center for Heart Failure and Arrhythmias, Davis Heart and Lung Research Institute, The Ohio State University, Columbus, OH, United States.

Na1.5, encoded by the gene , is the predominant voltage-gated sodium channel expressed in the heart. It initiates the cardiac action potential and thus is crucial for normal heart rhythm and function. Read More

View Article and Full-Text PDF

Electrical tunability of terahertz nonlinearity in graphene.

Sci Adv 2021 Apr 7;7(15). Epub 2021 Apr 7.

Fakultät für Physik, Universität Bielefeld, Universitätsstr. 25, 33615 Bielefeld, Germany.

Graphene is conceivably the most nonlinear optoelectronic material we know. Its nonlinear optical coefficients in the terahertz frequency range surpass those of other materials by many orders of magnitude. Here, we show that the terahertz nonlinearity of graphene, both for ultrashort single-cycle and quasi-monochromatic multicycle input terahertz signals, can be efficiently controlled using electrical gating, with gating voltages as low as a few volts. Read More

View Article and Full-Text PDF

Differential sensitivity of cinnamaldehyde-evoked calcium fluxes to ruthenium red in guinea pig and mouse trigeminal sensory neurons.

BMC Res Notes 2021 Apr 7;14(1):127. Epub 2021 Apr 7.

Molecular Pharmacology & Physiology, Morsani College of Medicine, University of South Florida, 12901 Bruce B Downs Blvd, Tampa, FL, 33612, USA.

Objective: Transient receptor potential ankyrin 1 (TRPA1) is an excitatory ion channel expressed on a subset of sensory neurons. TRPA1 is activated by a host of noxious stimuli including pollutants, irritants, oxidative stress and inflammation, and is thought to play an important role in nociception and pain perception. TRPA1 is therefore a therapeutic target for diseases with nociceptive sensory signaling components. Read More

View Article and Full-Text PDF

Toward Compact High-Performance Ion Mobility Spectrometers: Ion Gating in Ion Mobility Spectrometry.

Anal Chem 2021 Apr 7. Epub 2021 Apr 7.

Leibniz University Hannover, Institute of Electrical Engineering and Measurement Technology, Department of Sensors and Measurement Technology, Appelstrasse 9A, 30167 Hannover, Germany.

Printed circuit board (PCB) based drift tube ion mobility spectrometers enable the use of state-of-the-art production techniques to manufacture compact devices with excellent performance at minimum cost. The new PCB ion mobility spectrometer (PCB-IMS) presented here is equipped with either a 140 MBq tritium or a 95 MBq nickel-63 ionization source and consists of a combination of horizontally arranged 6-layer PCBs for the drift and reaction regions and vertically arranged PCBs for interfacing the ionization source, ion shutter, and detector. The design allows the reproducible manufacturing and thus comparison of different IMS topologies. Read More

View Article and Full-Text PDF

Single-Molecule Electrochemical Transistors.

Adv Mater 2021 Apr 6:e2005883. Epub 2021 Apr 6.

State Key Laboratory of Physical Chemistry of Solid Surfaces, Collaborative Innovation Center of Chemistry for Energy Materials (iChEM), College of Chemistry and Chemical Engineering, Xiamen University, Xiamen, 361005, China.

Single-molecule electrochemical transistors are a type of novel molecular devices in which the tunneling current through the single-molecule junction is modulated by the electrochemical gate, and is considered a promising candidate to be employed in molecular integrated circuits for building the future "molecular computers." Benefiting from the particular interfacial electrical double layer, the current modulation process can be realized through direct orbital gating as well as electrochemical electron transfer driven by electrode potential, thus significantly enriching the functions of the transistor devices. This review focuses on the transfer characteristics and the performance of several typical types of single-molecule electrochemical transistors and the prospects for the fabrication toward integrated devices. Read More

View Article and Full-Text PDF

Estrous cycle plasticity in the central clock output to kisspeptin neurons: Implications for the preovulatory surge.

Endocrinology 2021 Apr 7. Epub 2021 Apr 7.

Centre for Neuroendocrinology & Department of Physiology, University of Otago, Dunedin, New Zealand.

Coordination of ovulation and behavior is critical to reproductive success in many species. During the female estrous cycle, the preovulatory gonadotropin surge occurs when ovarian follicles reach maturity and, in rodents, begins just before the daily onset of activity, ensuring ovulation coincides with sex behavior. Timing of the surge relies on projections from the suprachiasmatic nucleus (SCN), the locus of the central circadian clock, to hypothalamic circuits that regulate gonadotropin secretion. Read More

View Article and Full-Text PDF

Kir4.1/Kir5.1 channels possess strong intrinsic inward rectification determined by a voltage-dependent K+-flux gating mechanism.

J Gen Physiol 2021 May;153(5)

Centro Universitario de Investigaciones Biomédicas, Universidad de Colima, Colima, México.

Inwardly rectifying potassium (Kir) channels are broadly expressed in both excitable and nonexcitable tissues, where they contribute to a wide variety of cellular functions. Numerous studies have established that rectification of Kir channels is not an inherent property of the channel protein itself, but rather reflects strong voltage dependence of channel block by intracellular cations, such as polyamines and Mg2+. Here, we identify a previously unknown mechanism of inward rectification in Kir4. Read More

View Article and Full-Text PDF

Unmasking coupling between channel gating and ion permeation in the muscle nicotinic receptor.

Elife 2021 Apr 6;10. Epub 2021 Apr 6.

Receptor Biology Laboratory, Department of Physiology and Biomedical Engineering, Rochester, United States.

Whether ion channel gating is independent of ion permeation has been an enduring, unresolved question. Here, applying single channel recording to the archetypal muscle nicotinic receptor, we unmask coupling between channel gating and ion permeation by structural perturbation of a conserved intramembrane salt bridge. A charge-neutralizing mutation suppresses channel gating, reduces unitary current amplitude, and increases fluctuations of the open channel current. Read More

View Article and Full-Text PDF

Theta oscillations gate the transmission of reliable sequences in the medial entorhinal cortex.

eNeuro 2021 Apr 2. Epub 2021 Apr 2.

Division of Biology, Indian Institute of Science Education and Research, Pune, India

Stability and precision of sequential activity in the entorhinal cortex is crucial for encoding spatially guided behavior and memory. These sequences are driven by constantly evolving sensory inputs and persist despite a noisy background. In a realistic computational model of a medial entorhinal cortex (MEC) microcircuit, we show that intrinsic neuronal properties and network mechanisms interact with theta oscillations to generate reliable outputs. Read More

View Article and Full-Text PDF

Non-invasive single photon imaging through strongly scattering media.

Opt Express 2021 Mar;29(7):9981-9990

Non-invasive optical imaging through opaque and multi-scattering media remains highly desirable across many application domains. The random scattering and diffusion of light in such media inflict exponential decay and aberration, prohibiting diffraction-limited imaging. By non-interferometric few picoseconds optical gating of backscattered photons, we demonstrate single photon sensitive non-invasive 3D imaging of targets occluded by strongly scattering media with optical thicknesses reaching 9. Read More

View Article and Full-Text PDF

STARGATE: A new instrument for high-resolution photodissociation spectroscopy of cold ionic species.

Rev Sci Instrum 2021 Mar;92(3):033307

Institute of Condensed Matter and Nanosciences, Université catholique de Louvain, Louvain-la-Neuve B-1348, Belgium.

Spectroscopy of transient anions and radicals by gated and accelerated time-of-flight experiment is a new spectrometer developed in UCLouvain. This instrument measures high-resolution photodissociation spectra of mass-selected ions by the combination of a time-of-flight spectrometer including a specific gating, bunching, and re-referencing unit with a nanosecond pulsed dye laser, a pulsed deflection, and an energy selector. The ionic species are generated in a supersonic jet expansion by means of an electric discharge or by the impact of electrons coming from an electron gun. Read More

View Article and Full-Text PDF

Mass-tag barcoding for multiplexed analysis of human synaptosomes and other anuclear events.

Cytometry A 2021 Apr 5. Epub 2021 Apr 5.

Department of Pathology, Stanford University, Stanford, California, USA.

Mass-tag cell barcoding has increased the throughput, multiplexing, and robustness of multiple cytometry approaches. Previously, we adapted mass cytometry for cells to analyze synaptosome preparations (mass synaptometry or SynTOF), extending mass cytometry to these smaller, anuclear particles. To improve throughput and individual event resolution, we report here the application of palladium-based barcoding in human synaptosomes. Read More

View Article and Full-Text PDF