Structure-Function Relationship of the Ryanodine Receptor Cluster Network in Sinoatrial Node Cells.

The rate of spontaneous action potentials (APs) generated by sinoatrial node cells (SANC) is regulated by local Ca release (LCR) from the sarcoplasmic reticulum via Ca release channels (ryanodine receptors, RyRs). LCR events propagate and self-organize within the network of RyR clusters (Ca release units, CRUs) via Ca-induced-Ca-release (CICR) that depends on CRU sizes and locations: While larger CRUs generate stronger release signals, the network's topology governs signal diffusion and propagation. This study used super-resolution structured illumination microscopy to image the 3D network of CRUs in rabbit SANC.

High-Statistics Measurement of Collins and Sivers Asymmetries for Transversely Polarized Deuterons.

New results are presented on a high-statistics measurement of Collins and Sivers asymmetries of charged hadrons produced in deep inelastic scattering of muons on a transversely polarized ^{6}LiD target. The data were taken in 2022 with the COMPASS spectrometer using the 160 GeV muon beam at CERN, statistically balancing the existing data on transversely polarized proton targets. The first results from about two-thirds of the new data have total uncertainties smaller by up to a factor of three compared to the previous deuteron measurements.

Final COMPASS Results on the Transverse-Spin-Dependent Azimuthal Asymmetries in the Pion-Induced Drell-Yan Process.

The COMPASS Collaboration performed measurements of the Drell-Yan process in 2015 and 2018 using a 190  GeV/c π^{-} beam impinging on a transversely polarized ammonia target. Combining the data of both years, we present final results on the amplitudes of five azimuthal modulations, which correspond to transverse-spin-dependent azimuthal asymmetries (TSAs) in the dimuon production cross section. Three of them probe the nucleon leading-twist Sivers, transversity, and pretzelosity transverse-momentum dependent (TMD) parton distribution functions (PDFs).

Thermal Stability of Highly Filled Cellulosic Biocomposites Based on Ethylene-Vinyl Acetate Copolymer.

The effect of plant-based fillers on thermal resistance in highly filled biocomposites based on ethylene-vinyl acetate copolymer (EVA) was studied. Wood flour and microcrystalline cellulose were used as fillers. It was shown that the introduction of microcrystalline cellulose into EVA did not affect the thermal stability of the polymer matrix.

Neuroprotective thiourea derivative uncouples mitochondria and exerts weak protonophoric action on lipid membranes.

The isothiourea derivative NT-1505 is known as a neuroprotector and cognition enhancer in animal models of neurodegenerative diseases. Bearing in mind possible relation of the NT-1505-mediated neuroprotection to mitochondrial uncoupling activity, here, we examine NT-1505 effects on mitochondria functioning. At concentrations starting from 10 μM, NT-1505 prevented Ca-induced mitochondrial swelling, similar to common uncouplers.

Dual network structure of the AV node.

Biological systems, particularly the brain, are frequently analyzed as networks, conveying mechanistic insights into their function and pathophysiology. This is the first study of a functional network of cardiac tissue. We use calcium imaging to obtain two functional networks in a subsidiary but essential pacemaker of the heart, the atrioventricular node (AVN).

A novel conceptual model of heart rate autonomic modulation based on a small-world modular structure of the sinoatrial node.

The present view on heartbeat initiation is that a primary pacemaker cell or a group of cells in the sinoatrial node (SAN) center paces the rest of the SAN and the atria. However, recent high-resolution imaging studies show a more complex paradigm of SAN function that emerges from heterogeneous signaling, mimicking brain cytoarchitecture and function. Here, we developed and tested a new conceptual numerical model of SAN organized similarly to brain networks featuring a modular structure with small-world topology.

Mitochondria and Oxidative Stress as a Link between Alzheimer's Disease and Diabetes Mellitus.

This review is devoted to the problems of the common features linking metabolic disorders and type 2 diabetes with the development of Alzheimer's disease. The pathogenesis of Alzheimer's disease closely intersects with the mechanisms of type 2 diabetes development, and an important risk factor for both pathologies is aging. Common pathological mechanisms include both factors in the development of oxidative stress, neuroinflammation, insulin resistance, and amyloidosis, as well as impaired mitochondrial dysfunctions and increasing cell death.

Early Postnatal Experience Modifies Activation of the Pituitary Testicular Complex in Male House Mice (Mus Musculus) Exposed to the Odor of Receptive Con- and Heterospecific Females.

For the first time, it was shown that activation of the pituitary-testicular complex in male house mice exposed to the odor of receptive females of their own and closely related species was modified under the influence of early postnatal experience and the maternal environment. We have confirmed associated formation of behavioral and physiological mechanisms of precopulatory isolation in early ontogenesis. The serum levels of free testosterone in males of closely related species M.

Elementary intracellular Ca signals approximated as a transition of release channel system from a metastable state.

Cardiac muscle contraction is initiated by an elementary Ca signal (called Ca spark) which is achieved by collective action of Ca release channels in a cluster. The mechanism of this synchronization remains uncertain. We approached Ca spark activation as an emergent phenomenon of an interactive system of release channels.

Order-Disorder Phase Transition and Ionic Conductivity in a LiBH Solid Electrolyte.

Temperature-induced phase transitions and ionic conductivities of LiBH and LiCBH were simulated with the use of machine learning interatomic potentials based on van der Waals-corrected density functional theory (rev-vdW-DF2 functional). The simulated temperature of order-disorder phase transition, lattice parameters, diffusion, ionic conductivity, and activation energies are in good agreement with experimental data. Our simulations of LiBH uncover the importance of the reorientational motion of the [BH] anion.

Correction: Krivonogov et al. Microbial Diversity and Authigenic Mineral Formation of Modern Bottom Sediments in the Littoral Zone of Lake Issyk-Kul, Kyrgyz Republic (Central Asia). 2023, , 642.

Sergei Krivonogov was not included as an author in the original publication [...

Ultralow reaction barriers for CO oxidation in Cu-Au nanoclusters.

Systematic structure prediction of CuAu nanoclusters was carried out for a wide compositional area ( + ≤ 15) using the evolutionary algorithm USPEX and DFT calculations. The obtained structural data allowed us to assess the local stability of clusters and their suitability for catalysis of CO oxidation. Using these two criteria, we selected several most promising clusters for an accurate study of their catalytic properties.

Microbial Diversity and Authigenic Mineral Formation of Modern Bottom Sediments in the Littoral Zone of Lake Issyk-Kul, Kyrgyz Republic (Central Asia).

This article presents geochemical, mineralogical and microbiological characteristics of five samples of modern bottom sediments in the littoral zone of the high-mountain salty lake Issyk-Kul. The 16S rRNA gene sequencing method shows that the microbial community consists of organic carbon degraders (representatives of phyla: , , and and families and ), photosynthetic microorganisms (representatives of , phototrophic , purple sulphur bacteria and cyanobacteria) and bacteria of the reducing branches of the sulphur biogeochemical cycle (representatives of , and ). The participation of microorganisms in processes in the formation of a number of authigenic minerals (calcite, framboidal pyrite, barite and amorphous Si) is established.

Chronic Administration of Non-Constitutive Proteasome Inhibitor Modulates Long-Term Potentiation and Glutamate Signaling-Related Gene Expression in Murine Hippocampus.

Proteasomes degrade most intracellular proteins. Several different forms of proteasomes are known. Little is known about the role of specific proteasome forms in the central nervous system (CNS).

Structure and Thermomechanical Properties of Polyvinylidene Fluoride Film with Transparent Indium Tin Oxide Electrodes.

This paper is devoted to the study of the structure and thermomechanical properties of PVDF-based ferroelectric polymer film. Transparent electrically conductive ITO coatings are applied to both sides of such a film. In this case, such material acquires additional functional properties due to piezoelectric and pyroelectric effects, forming, in fact, a full-fledged flexible transparent device, which, for example, will emit a sound when an acoustic signal is applied, and under various external influences can generate an electrical signal.

Combination of Total-Reflection X-Ray Fluorescence Method and Chemometric Techniques for Provenance Study of Archaeological Ceramics.

The provenance study of archaeological materials is an important step in understanding the cultural and economic life of ancient human communities. One of the most popular approaches in provenance studies is to obtain the chemical composition of material and process it with chemometric methods. In this paper, we describe a combination of the total-reflection X-ray fluorescence (TXRF) method and chemometric techniques (PCA, k-means cluster analysis, and SVM) to study Neolithic ceramic samples from eastern Siberia (Baikal region).

[Otorhinolaryngological symptoms of tumors of the pharyngeal process of the parotid saliva (clinical case with literature review)].

The parotid gland is the largest salivary gland. Tumors of the salivary gland account for 5% in the structure of oncological morbidity, and up to 80% of tumors affect the large salivary glands with tumor localization in 20% of cases in the pharyngeal process of the parotid salivary gland. The main clinical sign of a tumor of the parotid salivary gland is the presence of a slowly growing mass in the area of the gland.

Bidirectional regulation by "star forces": Ionotropic astrocyte's optical stimulation suppresses synaptic plasticity, metabotropic one strikes back.

The role of astrocytes in modulating synaptic plasticity is an important question that until recently was not addressed due to limitations of previously existing technology. In the present study, we took an advantage of optogenetics to specifically activate astrocytes in hippocampal slices in order to study effects on synaptic function. Using the AAV-based delivery strategy, we expressed the ionotropic channelrhodopsin-2 (ChR2) or the metabotropic Gq-coupled Opto-a1AR opsins specifically in hippocampal astrocytes to compare different modalities of astrocyte activation.

Amyloid Aβ Aggregates Say 'NO' to Long-Term Potentiation in the Hippocampus through Activation of Stress-Induced Phosphatase 1 and Mitochondrial Na/Ca Exchanger.

The search for strategies for strengthening the synaptic efficiency in Aβ-treated slices is a challenge for the compensation of amyloidosis-related pathologies. Here, we used the recording of field excitatory postsynaptic potentials (fEPSPs), nitric oxide (NO) imaging, measurements of serine/threonine protein phosphatase (STPP) activity, and the detection of the functional mitochondrial parameters in suspension of brain mitochondria to study the Aβ-associated signaling in the hippocampus. Aβ aggregates shifted the kinase-phosphatase balance during the long-term potentiation (LTP) induction in the enhancement of STPP activity.

The Heart's Pacemaker Mimics Brain Cytoarchitecture and Function: Novel Interstitial Cells Expose Complexity of the SAN.

Background: The sinoatrial node (SAN) of the heart produces rhythmic action potentials, generated via calcium signaling within and among pacemaker cells. Our previous work has described the SAN as composed of a hyperpolarization-activated cyclic nucleotide-gated potassium channel 4 (HCN4)-expressing pacemaker cell meshwork, which merges with a network of connexin 43/F-actin cells. It is also known that sympathetic and parasympathetic innervation create an autonomic plexus in the SAN that modulates heart rate and rhythm.

Disorder in Ca2+ release unit locations confers robustness but cuts flexibility of heart pacemaking.

Excitation-contraction coupling kinetics is dictated by the action potential rate of sinoatrial-nodal cells. These cells generate local Ca releases (LCRs) that activate Na/Ca exchanger current, which accelerates diastolic depolarization and determines the pace. LCRs are generated by clusters of ryanodine receptors, Ca release units (CRUs), residing in the sarcoplasmic reticulum.

Pharmacological sequestration of mitochondrial calcium uptake protects against dementia and β-amyloid neurotoxicity.

All forms of dementia including Alzheimer's disease are currently incurable. Mitochondrial dysfunction and calcium alterations are shown to be involved in the mechanism of neurodegeneration in Alzheimer's disease. Previously we have described the ability of compound Tg-2112x to protect neurons via sequestration of mitochondrial calcium uptake and we suggest that it can also be protective against neurodegeneration and development of dementia.