23,755 results match your criteria channels small

A small-molecule Psora-4 acts as a caloric restriction mimetic to promote longevity in C. elegans.

Geroscience 2021 May 14. Epub 2021 May 14.

Department of Biochemistry, Yong Loo Lin School of Medicine, National University of Singapore, Singapore, 117608, Singapore.

In populations around the world, the fraction of humans aged 65 and above is increasing at an unprecedented rate. Aging is the main risk factor for the most important degenerative diseases and this demographic shift poses significant social, economic, and medical challenges. Pharmacological interventions directly targeting mechanisms of aging are an emerging strategy to delay or prevent age-dependent diseases. Read More

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Homocysteine alters vasoreactivity of human internal mammary artery by affecting the K channel family.

Ann Transl Med 2021 Apr;9(8):625

Center for Basic Medical Research & Department of Cardiovascular Surgery, TEDA International Cardiovascular Hospital, Chinese Academy of Medical Sciences & Peking Union Medical College, Tianjin, China.

Background: Hyperhomocysteinemia is an independent risk factor for atherosclerotic heart disease. We previously demonstrated that disruption of calcium-activated potassium (K) channel activity is involved in homocysteine-induced dilatory dysfunction of porcine coronary arteries. Recently we reported that the K channel family, including large-, intermediate-, and small-conductance K (BK, IK, and SK) subtypes, are abundantly expressed in human internal mammary artery (IMA). Read More

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Falling-Point Recognition and Scoring Algorithm in Table Tennis Using Dual-Channel Target Motion Detection.

J Healthc Eng 2021 19;2021:5529981. Epub 2021 Apr 19.

Department of Basic Course, Wuhan Donghu University, Wuhan 430212, Hubei, China.

In table tennis, the ball has numerous characteristics of high speed, small size, and changeable trajectory. Due to these characteristics, the human eye often cannot accurately judge the ball's movement and position, leading to the problem of precise detection of the ball's falling point and movement tracking. In sports, the use of machine learning for locating and detecting the ball and the use of deep learning for reconstructing and displaying the ball's trajectories are considered futuristic technologies. Read More

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Dense-code free space transmission by local demultiplexing optical states of a composed vortex.

Opt Express 2021 May;29(10):14412-14424

We describe an innovative data transmission scheme exploiting optical vortices to multiplex and demultiplex independent data channels in a standard asynchronous laser link. We report extensive results of the proof of concept of the method, successfully used to transmit two parallel ASCII strings, demultiplexed and decoded in the far field of the radiation beam. A phase locked two arms interferometer is proved to be effective even accessing a small portion of the beam only. Read More

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Sevoflurane excites nociceptive sensory neurons by inhibiting K conductances in rats.

Neurosci Lett 2021 May 10;756:135951. Epub 2021 May 10.

Department of Pharmacology, School of Dentistry, Kyungpook National University, Daegu, 41940, Republic of Korea; Brain Science & Engineering Institute, Kyungpook National University, Daegu, 41940, Republic of Korea. Electronic address:

Sevoflurane, which is preferentially used as a day-case anesthetic based on its low blood solubility, acts on the central nervous system and exerts analgesic effects. However, it still remains unknown whether sevoflurane affects the excitability of nociceptive sensory neurons. Therefore, we conducted this study to examine the effects of sevoflurane on the excitability of small-sized dorsal root ganglion (DRG) neurons of rats using the whole-cell patch-clamp technique. Read More

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Semiconducting α'-boron sheet with high mobility and low all-boron contact resistance: a first-principles study.

Nanoscale 2021 May;13(18):8474-8480

Chemistry Department, Taif University, Taif, Saudi Arabia. and Department of Chemistry, Rice University, Houston, Texas 77005, USA.

Two-dimensional field effect transistors (2D FETs) with high mobility semiconducting channels and low contact resistance between the semiconducting channel and the metallic electrodes are highly sought components of future electronics. Recently, 2D boron sheets (borophene) offer a great platform for realizing ideal 2D FETs but stable semiconducting phases still remain much unexplored. Herein, based on first-principles calculations and tight-binding model, we first clarify that α'-boron is the most stable semiconductor phase of boron sheets, while reveal the mechanism of metal-to-semiconductor transition from α- to α'-boron. Read More

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Genetics of atrial fibrillation - practical applications for clinical management: If not now, when and how?

Cardiovasc Res 2021 May 12. Epub 2021 May 12.

Department of Cardiology, University Heart and Vascular Center, University Medical Center Hamburg Eppendorf, Hamburg, Germany.

The prevalence and economic burden of atrial fibrillation (AF) are predicted to more than double over the next few decades. In addition to anticoagulation and treatment of concomitant cardiovascular conditions, early and standardized rhythm control therapy reduces cardiovascular outcomes as compared with a rate control approach, favoring the restoration and maintenance of sinus rhythm safely. Current therapies for rhythm control of AF include anti-arrhythmic drugs (AAD) and catheter ablation (CA). Read More

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Bio-inspired incorporation of phenylalanine enhances ionic selectivity in layer-by-layer deposited polyelectrolyte films.

Soft Matter 2021 May 13. Epub 2021 May 13.

Sandia National Laboratories, PO Box 5800, MS 1411, Albuquerque, NM 87185, USA.

The addition of a common amino acid, phenylalanine, to a Layer-by-Layer (LbL) deposited polyelectrolyte (PE) film on a nanoporous membrane can increase its ionic selectivity over a PE film without the added amino acid. The addition of phenylalanine is inspired by detailed knowledge of the structure of the channelrhodopsins family of protein ion channels, where phenylalanine plays an instrumental role in facilitating sodium ion transport. The normally deposited and crosslinked PE films increase the cationic selectivity of a support membrane in a controllable manner where higher selectivity is achieved with thicker PE coatings, which in turn also increases the ionic resistance of the membrane. Read More

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Enlarged Phase Regions of Multi-Continuous 3D Network Nanostructures in ABC Triblock Copolymers.

Langmuir 2021 May 12. Epub 2021 May 12.

Faculty of Materials Science and Chemical Engineering, Ningbo University, Ningbo, Zhejiang 315211, China.

Aiming to increase the stability region of three-dimensional (3D) multi-continuous morphologies due to great potential application in smart sensors, gas separation membranes, and photonic materials, in this paper, we control the block ratio of different channels of an ABC triblock copolymer according to the curvature of these multi-continuous nanostructures. In the small A volume fraction region, the multi-continuous gyroid nanostructure is stable when / equals 1/3, while two-domain lamellae () and three-layer lamellae () are obtained when B and C blocks have comparable volume fractions, suggesting that changing the / ratio is an effective way of forming multi-continuous polymer network nanostructures. Interestingly, a large phase region of the core-shell gyroid and are found under the condition of / = 4. Read More

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Detecting pollutant sources and pathways: High-frequency automated online monitoring in a small rural French/German transborder catchment.

J Environ Manage 2021 May 7;290:112619. Epub 2021 May 7.

Institute of Inorganic and Analytical Chemistry, Saarland University, Dudweiler Zeile 4, 66125, Saarbruecken, Germany.

Great temporal and spatial variability of inputs make comprehensive monitoring in small and middle sized rivers difficult. In this study, relevant inputs in a small river were recorded with suitable online monitoring equipment coupled in mobile water quality monitoring stations, the study area being a transborder catchment with French and German (Saarland federal state) subcatchments. In addition to a pronounced spatial variability necessitating a denser net of measuring points this catchment has also to be assessed in the light of different national regulations. Read More

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MR-compatible optical microscope for in-situ dual-mode MR-optical microscopy.

PLoS One 2021 10;16(5):e0250903. Epub 2021 May 10.

Department of Microsystemes Engineering (IMTEK), Laborarory for Microactuators, University of Freiburg, Freiburg, Germany.

We present the development of a dual-mode imaging platform that combines optical microscopy with magnetic resonance microscopy. Our microscope is designed to operate inside a 9.4T small animal scanner with the option to use a 72mm bore animal RF coil or different integrated linear micro coils. Read More

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Inward calcium current through the polycystin-2-dependent channels of renal primary cilia.

Am J Physiol Renal Physiol 2021 May 10. Epub 2021 May 10.

Pharmacology & Systems Physiology, University of Cincinnati, United Statesgrid.24827.3b.

In 15% of cases, autosomal dominant polycystic kidney disease (ADPKD) arises from defects in polycystin-2 (PC2). PC2 is a member of the TRPP subfamily of cation-conducting channels and is expressed in the endoplasmic reticulum and primary cilium of renal epithelial cells. PC2 opposes a pro-cystogenic influence of the cilium, and it has been proposed that this beneficial effect is mediated in part by a flow of Ca through PC2 channels into the primary cilium. Read More

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Inhibition of Small-Conductance, Ca-Activated K Current by Ondansetron.

Front Pharmacol 2021 22;12:651267. Epub 2021 Apr 22.

Division of Cardiology, Department of Medicine, The Krannert Institute of Cardiology, Indiana University School of Medicine, Indianapolis, IN, United States.

Small-conductance Ca-activated K channels (SK channels) have been proposed as antiarrhythmic targets for the treatment of atrial fibrillation. We previously demonstrated that the 5-HT receptor antagonist ondansetron inhibits heterologously expressed, human SK2 (hSK2) currents as well as native cardiac SK currents in a physiological extra-/intracellular [K] gradient at therapeutic (i.e. Read More

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State Transitions During Discrimination Learning in the Gerbil Auditory Cortex Analyzed by Network Causality Metrics.

Front Syst Neurosci 2021 22;15:641684. Epub 2021 Apr 22.

Leibniz Institute for Neurobiology (LIN), Magdeburg, Germany.

This work studies the evolution of cortical networks during the transition from escape strategy to avoidance strategy in auditory discrimination learning in Mongolian gerbils trained by the well-established two-way active avoidance learning paradigm. The animals were implanted with electrode arrays centered on the surface of the primary auditory cortex and electrocorticogram (ECoG) recordings were made during performance of an auditory Go/NoGo discrimination task. Our experiments confirm previous results on a sudden behavioral change from the initial naïve state to an avoidance strategy as learning progresses. Read More

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Therapeutic Antibodies Targeting Potassium Ion Channels.

Handb Exp Pharmacol 2021 May 8. Epub 2021 May 8.

TetraGenetics Inc, Arlington, MA, USA.

Monoclonal antibodies combine specificity and high affinity binding with excellent pharmacokinetic properties and are rapidly being developed for a wide range of drug targets including clinically important potassium ion channels. Nonetheless, while therapeutic antibodies come with great promise, K channels represent particularly difficult targets for biologics development for a variety of reasons that include their dynamic structures and relatively small extracellular loops, their high degree of sequence conservation (leading to immune tolerance), and their generally low-level expression in vivo. The process is made all the more difficult when large numbers of antibody candidates must be screened for a given target, or when lead candidates fail to cross-react with orthologous channels in animal disease models due to their highly selective binding properties. Read More

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KCNK13 potassium channels in the ventral tegmental area of rats are important for excitation of VTA neurons by ethanol.

Alcohol Clin Exp Res 2021 May 7. Epub 2021 May 7.

Department of Physiology and Biophysics, University of Illinois at Chicago, Chicago, 60612.

Background: Alcohol excites neurons of the ventral tegmental area (VTA) and the release of dopamine from these neurons is a key event in ethanol reward and reinforcement. Many mechanisms for ethanol actions on neurons of the VTA have been proposed, but antagonists generally do not eliminate ethanol-induced excitation of VTA neurons. We have previously demonstrated that the ion channel KCNK13 plays an important role in ethanol excitation of mouse VTA neurons. Read More

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A Novel Modulator of STIM2-Dependent Store-Operated Ca2+ Channel Activity.

Acta Naturae 2021 Jan-Mar;13(1):140-146

Institute of Cytology of Russian Academy of Sciences, St. Petersburg, 194064 Russia.

Store-operated Ca entry is one of the main pathways of calcium influx into non-excitable cells, which entails the initiation of many intracellular processes. The endoplasmic reticulum Ca sensors STIM1 and STIM2 are the key components of store-operated Ca entry in mammalian cells. Under physiological conditions, STIM proteins are responsible for store-operated Ca entry activation. Read More

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On Local Activity and Edge of Chaos in a NaMLab Memristor.

Front Neurosci 2021 20;15:651452. Epub 2021 Apr 20.

Department of Electrical Engineering and Computer Sciences, University of California, Berkeley, Berkeley, CA, United States.

Local activity is the capability of a system to amplify infinitesimal fluctuations in energy. Complex phenomena, including the generation of action potentials in neuronal axon membranes, may never emerge in an open system unless some of its constitutive elements operate in a locally active regime. As a result, the recent discovery of solid-state volatile memory devices, which, biased through appropriate DC sources, may enter a local activity domain, and, most importantly, the associated stable yet excitable sub-domain, referred to as edge of chaos, which is where the seed of complexity is actually planted, is of great appeal to the neuromorphic engineering community. Read More

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Dendritic Mesoporous Silica Nanospheres: Toward the Ultimate Minimum Particle Size for Ultraefficient Liquid Chromatographic Separation.

ACS Appl Mater Interfaces 2021 May 6. Epub 2021 May 6.

State Key Laboratory of Analytical Chemistry for Life Science, School of Chemistry and Chemical Engineering, Nanjing University, 163 Xianlin Avenue, Nanjing 210023, China.

Use of smaller particle size of packing materials in liquid chromatography leads to faster separation and higher efficiency. This basic law has driven the evolution of packing materials for several generations. However, the use of nanoscale packing materials has been severely hampered by extremely high back pressure. Read More

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Tomographic X-ray scattering based on invariant reconstruction: analysis of the 3D nanostructure of bovine bone.

J Appl Crystallogr 2021 Apr 3;54(Pt 2):486-497. Epub 2021 Mar 3.

Department of Biomaterials, Max Planck Institute of Colloids and Interfaces, Am Mühlenberg 1, 14476 Potsdam, Germany.

Small-angle X-ray scattering (SAXS) is an effective characterization technique for multi-phase nanocomposites. The structural complexity and heterogeneity of biological materials require the development of new techniques for the 3D characterization of their hierarchical structures. Emerging SAXS tomographic methods allow reconstruction of the 3D scattering pattern in each voxel but are costly in terms of synchrotron measurement time and computer time. Read More

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Integration of sequential analytical processes into sub-100 nm channels: volumetric sampling, chromatographic separation, and label-free molecule detection.

Nanoscale 2021 May 4. Epub 2021 May 4.

Department of Bioengineering, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo 113-8656, Japan. and Department of Applied Chemistry, School of Engineering, The University of Tokyo, 7-3-1, Hongo, Bunkyo, Tokyo 113-8656, Japan.

The progress of nanotechnology has developed nanofluidic devices utilizing nanochannels with a width and/or depth of sub-100 nm (101 nm channels), and several experiments have been implemented in ultra-small spaces comparable to DNAs and proteins. However, current experiments utilizing 101 nm channels focus on a single function or operation; integration of multiple analytical operations into 101 nm channels using nanofluidic circuits and fluidic control has yet to be realized despite the advantage of nanochannels. Herein, we report the establishment of a label-free molecule detection method for 101 nm channels and demonstration of sequential analytical processes using integrated nanofluidic devices. Read More

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Calcium-Activated K Channels (KCa) and Therapeutic Implications.

Handb Exp Pharmacol 2021 May 5. Epub 2021 May 5.

Smooth Muscle Research Centre, Dundalk Institute of Technology, Dundalk, Ireland.

Potassium channels are the most diverse and ubiquitous family of ion channels found in cells. The Ca and voltage gated members form a subfamily that play a variety of roles in both excitable and non-excitable cells and are further classified on the basis of their single channel conductance to form the small conductance (SK), intermediate conductance (IK) and big conductance (BK) K channels.In this chapter, we will focus on the mechanisms underlying the gating of BK channels, whose function is modified in different tissues by different splice variants as well as the expanding array of regulatory accessory subunits including β, γ and LINGO subunits. Read More

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Small subpopulations of β-cells do not drive islet oscillatory [Ca2+] dynamics via gap junction communication.

PLoS Comput Biol 2021 May 3;17(5):e1008948. Epub 2021 May 3.

Department of Bioengineering, University of Colorado, Anschutz Medical campus, Aurora, Colorado, United States of America.

The islets of Langerhans exist as multicellular networks that regulate blood glucose levels. The majority of cells in the islet are excitable, insulin-producing β-cells that are electrically coupled via gap junction channels. β-cells are known to display heterogeneous functionality. Read More

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C-bouton components on rat extensor digitorum longus motoneurons are resistant to chronic functional overload.

J Anat 2021 May 3. Epub 2021 May 3.

Department of Neuromuscular Diseases, UCL Queen Square Institute of Neurology, University College London, London, UK.

Mammalian motor systems adapt to the demands of their environment. For example, muscle fibre types change in response to increased load or endurance demands. However, for adaptations to be effective, motoneurons must adapt such that their properties match those of the innervated muscle fibres. Read More

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Anisotropic Evaporator with a T-Shape Design for High-Performance Solar-Driven Zero-Liquid Discharge.

Small 2021 May 3:e2100969. Epub 2021 May 3.

State Key Laboratory of Applied Organic Chemistry, Lanzhou University, Lanzhou, Gansu, 730000, China.

Solar-driven evaporation is regarded as a sustainable wastewater treatment strategy for clean water recovery and salt condensation. However, achieving both high evaporation rate and long-term stability remain challenging due to poor thermal management and rapid salt accumulation and blocking. Here, a T-shape solar-driven evaporator, composed of a surface-carbonized longitudinal wood membrane (C-L-wood) is demonstrated as the top "" for solar harvesting/vapor generation/salt collection and another piece of natural L-wood as the support "" for brine transporting and thermally insulating. Read More

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College Students' Digital Media Preferences for future HPV Vaccine Campaigns.

J Cancer Educ 2021 May 2. Epub 2021 May 2.

College of Health Solutions, Arizona State University, 425 N. 5thStreet, Phoenix, AZ, 85004, USA.

In the USA, although college-aged populations are at the greatest risk for initial infection with human papillomavirus (HPV), they are one of the age-based populations with lower HPV vaccine rates, largely due to their lack of perceived need to vaccinate against HPV. Health communication campaigns can help address this perception. This research identifies college students' preferred digital media channels for future HPV vaccine communication campaigns. Read More

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A detailed characterization of the hyperpolarization-activated "funny" current (I) in human-induced pluripotent stem cell (iPSC)-derived cardiomyocytes with pacemaker activity.

Pflugers Arch 2021 May 2. Epub 2021 May 2.

The Cell Physiology MiLab, Department of Biosciences, Università degli Studi di Milano, Via Celoria 26, 20133, Milano, Italy.

Properties of the funny current (I) have been studied in several animal and cellular models, but so far little is known concerning its properties in human pacemaker cells. This work provides a detailed characterization of I in human-induced pluripotent stem cell (iPSC)-derived pacemaker cardiomyocytes (pCMs), at different time points. Patch-clamp analysis showed that I density did not change during differentiation; however, after day 30, it activates at more negative potential and with slower time constants. Read More

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Mitochondrial K channels and their implications for disease mechanisms.

Pharmacol Ther 2021 Apr 27:107874. Epub 2021 Apr 27.

Department of Biology, University of Padova, Italy; CNR Institute of Neurosciences, Italy. Electronic address:

The field of mitochondrial ion channels underwent a rapid development during the last decade, thanks to the molecular identification of some of the nuclear-encoded organelle channels and to advances in strategies allowing specific pharmacological targeting of these proteins. Thereby, genetic tools and specific drugs aided definition of the relevance of several mitochondrial channels both in physiological as well as pathological conditions. Unfortunately, in the case of mitochondrial K channels, efforts of genetic manipulation provided only limited results, due to their dual localization to mitochondria and to plasma membrane in most cases. Read More

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TRPM2 ion channels steer neutrophils towards a source of hydrogen peroxide.

Sci Rep 2021 Apr 29;11(1):9339. Epub 2021 Apr 29.

Wolfson Centre for Age-Related Diseases, King's College London, Guy's Campus, London Bridge, London, SE1 1UL, UK.

Neutrophils must navigate accurately towards pathogens in order to destroy invaders and thus defend our bodies against infection. Here we show that hydrogen peroxide, a potent neutrophil chemoattractant, guides chemotaxis by activating calcium-permeable TRPM2 ion channels and generating an intracellular leading-edge calcium "pulse". The thermal sensitivity of TRPM2 activation means that chemotaxis towards hydrogen peroxide is strongly promoted by small temperature elevations, suggesting that an important function of fever may be to enhance neutrophil chemotaxis by facilitating calcium influx through TRPM2. Read More

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