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Stimulation of sympathetic nerves in the vas deferens yields biphasic contractions consisting of a rapid transient component resulting from activation of P2X1 receptors by ATP and a secondary sustained component mediated by activation of α1-adrenoceptors by noradrenaline. Noradrenaline can also potentiate the ATP-dependent contractions of the vas deferens, but the mechanisms underlying this effect are unclear. The purpose of the present study was to investigate the mechanisms underlying potentiation of transient contractions of the vas deferens induced by activation of α1-adrenoceptors. Contractions of the mouse vas deferens were induced by electric field stimulation (EFS). Delivery of brief (1s duration) pulses (4 Hz) yielded transient contractions that were inhibited tetrodotoxin (100 nM) and guanethidine (10 µM). α,β-meATP (10 µM), a P2X1R desensitising agent, reduced the amplitude of these responses by 65% and prazosin (100 nM), an α1-adrenoceptor antagonist, decreased mean contraction amplitude by 69%. Stimulation of α1-adrenoceptors with phenylephrine (3 µM) enhanced EFS and ATP-induced contractions and these effects were mimicked by the phorbol ester PDBu (1 µM), which activates PKC. The PKC inhibitor GF109203X (1 µM) prevented the stimulatory effects of PDBu on ATP-induced contractions of the vas deferens but only reduced the stimulatory effects of phenylephrine by 40%. PDBu increased the amplitude of ATP-induced currents recorded from freshly isolated vas deferens myocytes and HEK-293 cells expressing human P2X1Rs by 93%. This study indicates that: (1) potentiation of ATP-evoked contractions of the mouse vas deferens by α1-adrenoceptor activation were not fully blocked by the PKC inhibitor GF109203X and (2) that the stimulatory effect of PKC on ATP-induced contractions of the vas deferens is associated with enhanced P2X1R currents in vas deferens myocytes.

Let T be an injective bounded linear operator on a complex Hilbert space. We characterize the complex numbers λ , μ for which (I + λ T) (I + μ T) − 1 is a contraction, the characterization being expressed in terms of the numerical range of the possibly unbounded operator T − 1. When T = V , the Volterra operator on L 2 [ 0 , 1 ] , this leads to a result of Khadkhuu, Zemánek and the second author, characterizing those λ , μ for which (I + λ V) (I + μ V) − 1 is a contraction. Taking T = V n , we further deduce that (I + λ V n) (I + μ V n) − 1 is never a contraction if n ≥ 2 and λ ≠ μ. [ABSTRACT FROM AUTHOR]

We study fixed-point theorems of contractive mappings in b-metric space, cone b-metric space, and the newly introduced extended b-metric space. To generalize an existence and uniqueness result for the so-called Φ s functions in the b-metric space to the extended b-metric space and the cone b-metric space, we introduce the class of Φ M functions and apply the Hölder continuous condition in the extended b-metric space. The obtained results are applied to prove the existence and uniqueness of solutions and positive solutions for nonlinear integral equations and fractional boundary value problems. Examples and numerical simulation are given to illustrate the applications. [ABSTRACT FROM AUTHOR]

Purpose: Eccentric quasi-isometric (EQI) resistance training is emerging as a promising option in sports medicine and rehabilitation. Despite prior research on EQI contractions in quadriceps and biceps brachii, their use in hamstring injury contexts is underexplored. Therefore, our study examines and contrasts the biomechanics and fatigue effects of EQI training on knee extensors and flexors. Methods: Following familiarization, 16 healthy, active participants (9 men, 7 women; 23.5 ± 2.6 years, 72.1 ± 12.8 kg, 173.4 ± 10.7 cm) performed, in random order, four EQI contractions for knee extensions and flexions, respectively. EQI contractions were isotonically loaded to 70% of concentric (60°·s−1) maximal voluntary contraction. Rest between repetitions was set at three minutes, while four minutes separated each muscle group. Peak torque, mean torque, and optimal angle were evaluated pre- and post-bouts. Inter-repetition contraction time and angular velocity were also assessed. Results: Average torque was 160.9 ± 44.2 and 71.5 ± 23.2 Nm for the extensors and flexors. Peak and mean torque significantly decreased for both extensors (p < 0.001, d = 0.70–0.71) and flexors (p ≤ 0.022, d = 0.36) after EQI contractions, respectively. However, the optimal angle increased for extensors (p < 0.001, d = 1.00) but not flexors (p = 0.811, d = 0.06). During EQI contractions, knee flexors exhibited greater intra-repetition velocity than extensors (p = 0.002; η2 = 0.50). Decreases in inter-repetition time and range of motion were more consistent for the extensors. Conclusions: Distinct responses exist when comparing EQI contractions of the knee extensors and flexors, particularly their effect on peak torque angles. These findings suggest knee flexors may require lower relative intensities to align more closely with extensor EQI contractions. [ABSTRACT FROM AUTHOR]

Estradiol (E2) and relaxin (Rln) are steroid and polypeptide hormones, respectively, with important roles in the female reproductive tract, including myometrium. Some actions of Rln, which are mediated by its membrane receptor RXFP1, require or are augmented by E2 signaling through its cognate nuclear steroid receptor, estrogen receptor alpha (ERα). In contrast, other actions of Rln act in opposition to the effects of E2. Here we explored the molecular and genomic mechanisms that underlie the functional interplay between E2 and Rln in the myometrium. We used both ovariectomized female mice and immortalized human myometrial cells expressing wild-type or mutant ERα (hTERT-HM-ERα cells). Our results indicate that Rln modulates the genomic actions and biological effects of estrogen in the myometrium and myometrial cells by reducing phosphorylation of ERα on serine 118 (S118), as well as by reducing the E2-dependent binding of ERα across the genome. These effects were associated with changes in the hormone-regulated transcriptome, including a decrease in the E2-dependent expression of some genes and enhanced expression of others. The inhibitory effects of Rln cotreatment on the E2-dependent phosphorylation of ERα required the nuclear dual-specificity phosphatases DUSP1 and DUSP5. Moreover, the inhibitory effects of Rln were reflected in a concomitant inhibition of the E2-dependent contraction of myometrial cells. Collectively, our results identify a pathway that integrates Rln/RXFP1 and E2/ERα signaling, resulting in a convergence of membrane and nuclear signaling pathways to control genomic and biological outcomes. [ABSTRACT FROM AUTHOR]

We reorganize, simplify and expand the theory of contractions or interior products of multivectors, and related topics like Hodge star duality. Many results are generalized and new ones are given, like: geometric characterizations of blade contractions and regressive products, higher-order graded Leibniz rules, determinant formulas, improved complex star operators, etc. Different contractions found in the literature are discussed and compared, in special those of Clifford Geometric Algebra. Applications of the theory are developed in a follow-up paper. [ABSTRACT FROM AUTHOR]

Problem: Uterine contractions signal labor onset, with elevated pro‐inflammatory cytokines playing a pivotal role. Prior studies have explored their effects on prostaglandins, oxytocin, and signaling pathways, but have overlooked their direct effects on uterine contractions. Here, we aim to investigate the direct effects of interleukin‐1β (IL‐1β), interleukin‐6 (IL‐6), and tumor necrosis factor‐α (TNF‐α) on contractions to ascertain if they have immediate observable effects like those reported for lipopolysaccharide (LPS) and other effects. Method of Study: Tension recordings were used to assess the direct effects of cytokines and/or LPS on mouse uterine contractions. Calcium imaging was employed to observe calcium oscillations in cytokine‐pretreated myometrial smooth muscle cells (MSMCs) in response to oxytocin. The release of inflammatory cytokines and chemokines from uterine explants after LPS and/or cytokines application was investigated using Luminex. Results: IL‐1β, IL‐6, and TNF‐α rapidly enhanced contractions of term pregnant mouse uterus. LPS combined with TNF‐α intensified contractions compared to LPS alone, although this effect was not statistically significant in our results (p > 0.050). Pretreatment of MSMCs with IL‐1β, IL‐6, or TNF‐α increased calcium oscillations in response to oxytocin. LPS and/or cytokine significantly stimulated the release of IL‐1β, IL‐6, TNF‐α, Chemokine (C‐X‐C motif) ligand 1 (CXCL1), and monocyte chemoattractant protein‐1 (MCP1) from uterine explants in vitro. Conclusions: Inflammatory cytokines have short‐term and long‐term effects on mouse uterine contractions, which together contribute to progressively stronger contractions during labor. [ABSTRACT FROM AUTHOR]

Contraction of solid elements and compounds by cooling from room temperature to 0 K or by mechanical pressing to the same volume at 298 K is experimentally determined. We found that the energy cost of cold compression exceeds the energy of mechanical compression on average by two orders of magnitude. This fact is caused by the different mechanisms of contraction: pressing directly reduces interatomic distances, cooling mainly reduces the amplitudes of harmonic vibrations of atoms, whereas the anharmonic part of the vibration energy, responsible for the thermal contraction, is very small, ca. 1%. [ABSTRACT FROM AUTHOR]

Objective: Atomoxetine (ATX), a selective noradrenaline re-uptake inhibitor, is a preferred drug with sufficient efficacy and favorable safety profile for the treatment of attention-deficit hyperactivity disorder. Ejaculatory dysfunctions have been reported in the patients receiving ATX as sexual side effects, of which underlying mechanisms are largely unknown. The present study aimed to investigate the effect of ATX on mouse isolated vas deferens (VD) contractility as a potential mechanism of ATX-induced ejaculatory dysfunction. Material and Methods: Isolated organ bath studies were performed on prostatic parts of VD obtained from adult male Balb/c mice. The effect of ATX (10-6, 10-5, 3x10-5 and 10-4 M) on KCl (80 mM)-, phenylephrine (PhE, 3x10-4 M)-, adenosine 5'-triphosphate (ATP, 10-2 M)- and electrical field stimulation (EFS; 100 V, 64 Hz)-induced contractions of VD strips were evaluated in concentration dependent manner. Results: ATX at 10-6 and 10-5 did not alter the contractile responses (p > 0.05), however, higher concentrations of ATX (3x10-5 or 10-4 M) significantly inhibited the KCl-, PhE-, ATP- and EFSinduced contractions of VD strips (p < 0.05). Conclusion: The present study demonstrated for the first time that ATX decreased the contractile responses of mouse isolated VD concentration-dependently. Our results suggest that ejaculatory dysfunction might be related to the inhibitory effect of ATX on VD. [ABSTRACT FROM AUTHOR]

The main goal of the article is the creation and study of thermosensitive and wound-healing gelatin-alginate biopolymer hydrogels modified with humic acids. Their rheological properties, swelling and contraction behavior were experimentally investigated, elucidated using Fourier transform infrared spectroscopy and used to achieve the physiological melting point, which is necessary for successful drug delivery. It has been shown that in the gelatin-alginate-humic acid biopolymer hydrogels systems, it is possible to obtain a gel-sol transition temperature close to the physiological temperature of 37°C, which is important for drug delivery in the treatment of wounds. By changing the type and concentration of humic acids in the gelatin-alginate hydrogel, it turned out to be achievable to regulate the softening time of the gel on the human body in the range from 6 to 20 min, which provides the possibility of controlled prolonged delivery of drugs. Based on the study of the influence of calcium ions on the properties of humic acids and ion exchange, as well as the interaction of humic acids, sodium alginate and gelatin with the formation of tighter gel networks, approaches to regulate the rate of softening of hydrogels at physiological temperature and their swelling, which simulates the absorption of exudate, were proposed and implemented. In addition, low shrinkage of the hydrogel surface due to cross-linking of gelatin-alginate networks when modified with humic acids was experimentally confirmed, which is important for avoiding problems of wound contracture and contour deformations when using dressings for wound healing. Thus, the developed optimized innovative biopolymer hydrogels synergistically combine the outstanding properties of natural molecular polymers and humic acids and are promising for the creation of effective medicines for wound healing. [ABSTRACT FROM AUTHOR]

Skeletal muscle plays a crucial role in generating force to facilitate movement. Skeletal muscle is a heterogenous tissue composed of diverse fibers with distinct contractile and metabolic profiles. The intricate classification of skeletal muscle fibers exists on a continuum ranging from type I (slow-twitch, oxidative) to type II (fast-twitch, glycolytic). The heterogenous distribution and characteristics of fibers within and between skeletal muscles profoundly influences cellular signaling; however, this has not been broadly discussed as it relates to macroautophagy/autophagy. The growing interest in skeletal muscle autophagy research underscores the necessity of comprehending the interplay between autophagic responses among skeletal muscles and fibers with different contractile properties, metabolic profiles, and other related signaling processes. We recommend approaching the interpretation of autophagy findings with careful consideration for two key reasons: 1) the distinct behaviors and responses of different skeletal muscles or fibers to various perturbations, and 2) the potential impact of alterations in skeletal muscle fiber type or metabolic profile on observed autophagic outcomes. This review provides an overview of the autophagic profile and response in skeletal muscles/fibers of different types and metabolic profiles. Further, this review discusses autophagic findings in various conditions and diseases that may differentially affect skeletal muscle. Finally, we provide key points of consideration to better enable researchers to fine-tune the design and interpretation of skeletal muscle autophagy experiments. Abbreviation: AKT1: AKT serine/threonine kinase 1; AMPK: AMP-activated protein kinase; ATG: autophagy related; ATG4: autophagy related 4 cysteine peptidase; ATG5: autophagy related 5; ATG7: autophagy related 7; ATG12: autophagy related 12; BECN1: beclin 1; BNIP3: BCL2 interacting protein 3; CKD: chronic kidney disease; COPD: chronic obstructive pulmonary disease; CS: citrate synthase; DIA: diaphragm; EDL: extensor digitorum longus; FOXO3/FOXO3A: forkhead box O3; GAS; gastrocnemius; GP: gastrocnemius-plantaris complex; MAP1LC3/LC3: microtubule associated protein 1 light chain 3; MAPK: mitogen-activated protein kinase; MYH: myosin heavy chain; PINK1: PTEN induced kinase 1; PLANT: plantaris; PRKN: parkin RBR E3 ubiquitin protein ligase; QUAD: quadriceps; RA: rectus abdominis; RG: red gastrocnemius; RQ: red quadriceps; SOL: soleus; SQSTM1: sequestosome 1; TA: tibialis anterior; WG: white gastrocnemius; WQ: white quadriceps; WVL: white vastus lateralis; VL: vastus lateralis; ULK1: unc-51 like autophagy activating kinase 1. [ABSTRACT FROM AUTHOR]

In this work, we obtain contraction results for a class of diagrams of ring morphisms which strictly includes the ones obtained by Lipman. Further, we present some applications on quotient and in the changing of the base ring in the saturation. [ABSTRACT FROM AUTHOR]

Abstract In this paper, we investigate the optimal conditions to the boundaries where the unique existence of the solutions to an advection-diffusion-reaction equation is secured by applying the contraction mapping theorem from the study of fixed points. Also, we extract, traveling wave solutions of the underlying equation. To this purpose, a new extended direct algebraic method with traveling wave transformation has been used. Achieved soliton solutions are different functions which are hyperbolic, trigonometric, exponential, and some mixed trigonometric functions. These functions show the nature of solitons. Two and three-dimensional plots are drawn using different values of parameters and coefficients for the comparison and behavior of solitons as combined bright-dark, dark, and bright solitons.

Abstract The level of airway constriction in thin slices of lung tissue is highly variable. Owing to the labor-intensive nature of these experiments, determining the number of airways to be analyzed in order to allocate a reliable value of constriction in one mouse is challenging. Herein, a new automated device for physiology and image analysis was used to facilitate high throughput screening of airway constriction in lung slices. Airway constriction was first quantified in slices of lungs from male BALB/c mice with and without experimental asthma that were inflated with agarose through the trachea or trans-parenchymal injections. Random sampling simulations were then conducted to determine the number of airways required per mouse to quantify maximal constriction. The constriction of 45 ± 12 airways per mouse in 32 mice were analyzed. Mean maximal constriction was 37.4 ± 32.0%. The agarose inflating technique did not affect the methacholine response. However, the methacholine constriction was affected by experimental asthma (p = 0.003), shifting the methacholine concentration–response curve to the right, indicating a decreased sensitivity. Simulations then predicted that approximately 35, 16 and 29 airways per mouse are needed to quantify the maximal constriction mean, standard deviation and coefficient of variation, respectively; these numbers varying between mice and with experimental asthma.

Myotropes are pharmaceuticals that have recently been developed or are under investigation for the treatment of heart diseases. Myotropes have had varied success in clinical trials. Initial research into myotropes have widely focused on animal models of cardiac dysfunction in comparison with normal animal cardiac physiology—primarily using males. In this study we examined the effect of danicamtiv, which is one type of myotrope within the class of myosin activators, on contractile function in permeabilized (skinned) myocardial strips from male and female Sprague–Dawley rats. We found that danicamtiv increased steady-state isometric force production at sub-maximal calcium levels, leading to greater Ca2+-sensitivity of contraction for both sexes. Danicamtiv did not affect maximal Ca2+-activated force for either sex. Sinusoidal length-perturbation analysis was used to assess viscoelastic myocardial stiffness and cross-bridge cycling kinetics. Data from these measurements did not vary with sex, and the data suggest that danicamtiv slows cross-bridge cycling kinetics. These findings imply that danicamtiv increases force production via increasing cross-bridge contributions to activation of contraction, especially at sub-maximal Ca2+-activation. The inclusion of both sexes in animal models during the formative stages of drug development could be helpful for understanding the efficacy or limitation of a drug's therapeutic impact on cardiac function. [ABSTRACT FROM AUTHOR]

The level of airway constriction in thin slices of lung tissue is highly variable. Owing to the labor-intensive nature of these experiments, determining the number of airways to be analyzed in order to allocate a reliable value of constriction in one mouse is challenging. Herein, a new automated device for physiology and image analysis was used to facilitate high throughput screening of airway constriction in lung slices. Airway constriction was first quantified in slices of lungs from male BALB/c mice with and without experimental asthma that were inflated with agarose through the trachea or trans-parenchymal injections. Random sampling simulations were then conducted to determine the number of airways required per mouse to quantify maximal constriction. The constriction of 45 ± 12 airways per mouse in 32 mice were analyzed. Mean maximal constriction was 37.4 ± 32.0%. The agarose inflating technique did not affect the methacholine response. However, the methacholine constriction was affected by experimental asthma (p = 0.003), shifting the methacholine concentration–response curve to the right, indicating a decreased sensitivity. Simulations then predicted that approximately 35, 16 and 29 airways per mouse are needed to quantify the maximal constriction mean, standard deviation and coefficient of variation, respectively; these numbers varying between mice and with experimental asthma. [ABSTRACT FROM AUTHOR]

In this paper, we consider a planar viscous shock of moderate strength for a scalar viscous conservation law in multi-D. We consider a strictly convex flux, as a small perturbation of the Burgers flux, along the normal direction to the shock front. However, for the transversal directions, we do not have any restrictions on flux function. We first show the contraction property for any large perturbations in L2 of the planar viscous shock. If the initial L2-perturbation is also in L1, the large perturbation converges to zero in L2 as time goes to infinity with t−1/4 decay rate. The contraction and decay estimates hold up to dynamical shift. For the results, we do not impose any smallness conditions on the initial value. This result extends the 1D case [M.-J. Kang and A. F. Vasseur, L2-contraction for shock waves of scalar viscous conservation laws, Ann. Inst. H. Poincaré C Anal. Non Linéaire 34 (2017) 139–156] by the first author and Vasseur to the multi-dimensional case. [ABSTRACT FROM AUTHOR]

Fixed-point theory, which has been developing since 1922, is widely used. Various contraction principles have been defined in the literature. In this work, we define rational-type contraction and weak Choudhury type contraction using α -series in F-metric spaces and prove common fixed-point theorems for sequences of self-mappings. This method is based on the convergence series of coefficients. Our results are the generalized version of the results in the literature. Finally, we apply our main results to solve an integral equation and a differential equation. [ABSTRACT FROM AUTHOR]

Age-related impairment of the diaphragm causes respiratory complications. Neuromuscular junction (NMJ) dysfunction can be one of the triggering events in diaphragm weaknesses in old age. Prominent structural and functional alterations in diaphragm NMJs were described in elderly rodents, but NMJ changes in middle age remain unclear. Here, we compared diaphragm muscles from young adult (3 months) and middle-aged (12 months) BALB/c mice. Microelectrode recordings, immunofluorescent staining, electron microscopy, myography, and whole-body plethysmography were used. We revealed presynaptic (i) and postsynaptic (ii) changes. The former (i) included an increase in both action potential propagation velocity and neurotransmitter release evoked by low-, moderate-, and high-frequency activity but a decrease in immunoexpression of synapsin 1 and synaptic vesicle clustering. The latter (ii) consisted of a decrease in currents via nicotinic acetylcholine receptors and the area of their distribution. These NMJ changes correlated with increased contractile responses to moderate- to high-frequency nerve activation. Additionally, we found alterations in the pattern of respiration (an increase in peak inspiratory flow and a tendency of elevation of the tidal volume), which imply increased diaphragm activity in middle-aged mice. We conclude that enhancement of neuromuscular communication (due to presynaptic mechanism) accompanied by improved contractile responses occurs in the diaphragm in early aging. [ABSTRACT FROM AUTHOR]

Background: Clonidine has been used in clinical medicine, e.g., to treat high blood pressure and other conditions. Animal studies have linked its use to impairments of male reproductive functions, and although only a few reports exist for the human species, such actions may exist in man as well. The underlying reasons and, specifically, possible actions of clonidine at the level of the testis are not known. Introduction: Clonidine is an agonist at the α2A-adrenoceptor (ADRA2A), which, as data bank mining indicated, is expressed by several cells of the human testis. The human testis and most of its cells are, however, not readily accessible to experimental testing. Cells from the peritubular wall compartment (human testicular peritubular cells; HTPCs) are the exception. Methods and Results: As shown by immunohistochemical/immunocytochemical and PCR techniques these cells express ADRA2A and retain expression upon isolation and culture. When tested over a concentration range (1–1000 µM) and 24 h, clonidine did not visibly affect HTPC morphology but significantly stimulated IL6 mRNA levels in a concentration-dependent manner. ELISA measurements of cell culture supernatants confirmed a stimulatory action of clonidine (10 µM) on secreted IL6. When examined in collagen gel contraction assays of HTPCs, clonidine (10 µM) exerted a slight relaxing action, while a proteomic study revealed that clonidine (10 µM) did not significantly change cellular protein abundance of HTPCs after 24 h (data available via ProteomeXchange with identifier PXD052220). Conclusion: Thus, ADRA2A-bearing cells in the human testis are targets for catecholamines and drugs such as clonidine. The results of this HTPCs-focused study only show the tip of the iceberg. It is likely that catecholamines/catecholaminergic drugs have the potential to interfere with human testicular functions. [ABSTRACT FROM AUTHOR]

We give a survey of the implosion construction, extending some of its aspects relating to hypertoric geometry from type A to a general reductive group, and interpret it in the context of the Moore–Tachikawa category. We use these ideas to discuss how the contraction construction in symplectic geometry can be generalized to the hyperkähler or complex symplectic situation. [ABSTRACT FROM AUTHOR]

This article presents a systematic approach to nonlinear state‐feedback control design that has three main advantages: (i) it ensures exponential stability and ℒ2$$ {\mathcal{L}}_2 $$‐gain performance with respect to a user‐defined set of reference trajectories, (ii) it provides constructive conditions based on convex optimization and a path‐integral‐based control realization, and (iii) it is less restrictive than previous similar approaches. In the proposed approach, first a virtual representation of the nonlinear dynamics is constructed for which a behavioral (parameter‐varying) embedding is generated. Then, by introducing a virtual control contraction metric, a convex control synthesis formulation is derived. Finally, a control realization with a virtual reference generator is computed, which is guaranteed to achieve exponential stability and ℒ2$$ {\mathcal{L}}_2 $$‐gain performance for all trajectories of the targeted reference behavior. We show that the proposed methodology is a unified generalization of the two distinct categories of linear‐parameter‐varying (LPV) state‐feedback control approaches: global and local methods. Moreover, it provides rigorous stability and performance guarantees as a method for nonlinear tracking control, while such properties are not guaranteed for tracking control using standard LPV approaches. Code is available at https://github.com/ruigangwang7/VCCM. [ABSTRACT FROM AUTHOR]

In this study, we prove a common fixed-point theorem for generalized rational-type contraction in supermetric space. Our findings expand the contractions of metric spaces to a supermetric space through Kannan's contraction, Reich's contraction, and Dass-Gupta's rational contraction. These theorems also extend to the supermetric context and generalize many interesting results from metric fixedpoint theory. Additionally, we provide an example to elucidate our theorems. [ABSTRACT FROM AUTHOR]

This paper summarises several contributions to the theory of belief change by the authors' dissertation thesis. First, a relational characterization of belief revision for Tarskian logics is considered, encompassing first-order predicate logic, description logic, modal logics and many monotonic logics with model-theoretic semantics. Those logics where total preorders are the standard semantics for revision are characterized. The second contribution considered is a theory of belief revision that builds upon the idea that agents are limited in what the outcome of a revision is. Furthermore, advancements in principles for iterated belief contraction given in the thesis are outlined. [ABSTRACT FROM AUTHOR]

We show that there is a simple derivation of triviality with very few assumptions involving the formula that the negated conditional entails the antecedent of the conditional. [ABSTRACT FROM AUTHOR]

In this paper we prove new fixed point results in partially ordered bicomplete quasimetric spaces. Our results extends/generalized celebrated results, on the one hand, by Nieto and Rodríguez-López for contraction mappings in partially ordered complete metric spaces and, on the other hand, by Schellekens for contraction mappings in bicomplete quasi-metric spaces. Moreover, it is also shown that neither our assumptions can be weakened nor our results can be deduced from the celebrated Kleene's fixed point theorem. Finally, an application of our results to the asymptotic analysis of recurrence equations is given. [ABSTRACT FROM AUTHOR]

The study of the coagulation-fragmentation model has provided insights into various engineering and scientific disciplines. However, the characteristics of particle ensembles are determined by multiple parameters in a multidimensional parameter space, including mass, volume, porosity, binder content, enthalpy, mole number, and more. This work focuses on establishing the existence of a continuous solution for the higher dimensional model, subject to certain restrictions on the kernels. Additionally, the conservation of volume of the solution are investigated. The results are derived based on the compactness result of Arzelà-Ascoli and the Banach contraction mapping principle. [ABSTRACT FROM AUTHOR]

In the present paper, we obtain three results on the existence of a fixed point for nonexpansive mappings. Two of them are generalizations of the result for F-contraction, while third one is a generalization of a recent result for set-valued contractions. [ABSTRACT FROM AUTHOR]

Diphenyleneiodonium (DPI) has been widely used as an inhibitor of NADPH oxidase (Nox) to discover its function in cardiac myocytes under various stimuli. However, the effects of DPI itself on Ca2+ signaling and contraction in cardiac myocytes under control conditions have not been understood. We investigated the effects of DPI on contraction and Ca2+ signaling and their underlying mechanisms using video edge detection, confocal imaging, and whole-cell patch clamp technique in isolated rat cardiac myocytes. Application of DPI suppressed cell shortenings in a concentration-dependent manner (IC50 of -0.17 µM) with a maximal inhibition of ~70% at ~100 µM. DPI decreased the magnitude of Ca2+ transient and sarcoplasmic reticulum Ca2+ content by 20%-30% at 3 µM that is usually used to remove the Nox activity, with no effect on fractional release. There was no significant change in the half-decay time of Ca2+ transients by DPI. The L-type Ca2+ current (ICa) was decreased concentration-dependently by DPI (IC50 of -40.3 µM) with -13.1%-inhibition at 3 µM. The frequency of Ca2+ sparks was reduced by 3 µM DPI (by ~25%), which was resistant to a brief removal of external Ca2+ and Na+. Mitochondrial superoxide level was reduced by DPI at 3-100 µM. Our data suggest that DPI may suppress L-type Ca2+ channel and RyR, thereby attenuating Ca2+-induced Ca2+ release and contractility in cardiac myocytes, and that such DPI effects may be related to mitochondrial metabolic suppression. [ABSTRACT FROM AUTHOR]

Shoulder muscles are active during front-crawl swimming to provide propulsion and stabilize the glenohumeral and scapulothoracic joints. Researchers have proposed that fatigue might contribute to altered activation of these muscles and represent a risk factor for injuries. Tensiomyography (TMG) might function as a noninvasive tool to detect changes in contractile measures of the skeletal muscles due to exercise-induced neuromuscular fatigue, though it has not yet been used in the shoulder muscles of swimmers. To assess the effects of a fatiguing swimming protocol on shoulder muscle TMG measures and isometric strength in competitive swimmers. Cross-sectional study. Swimming pool facility. A total of 14 young front-crawl competitive swimmers (11 males and 3 females; age = 21 ± 3 years [range, 17–26 years], height = 1.78 ± 0.06 m, mass = 73.1 ± 9.2 kg). Participants completed TMG and isometric strength assessments before and after 30-minute, high-intensity swim training. The TMG assessment was performed on 7 muscles of the shoulder according to front-crawl biomechanics and the applicability of the technique to obtain data, such as time to contraction and muscle-belly radial displacement. Isometric strength was assessed using a digital handheld dynamometer during shoulder flexion, extension, external rotation, and internal rotation. Fatigue induced a smaller radial displacement, mostly observable in latissimus dorsi (−1.0 mm; 95% CI = −1.7, −0.3 mm; P =.007) and pectoralis major muscles (−1.4 mm; 95% CI = −2.4, −0.4 mm; P =.007). Only shoulder extension showed an isometric strength reduction after the fatiguing protocol (−0.03 N/kg; 95% CI = −0.05, −0.01 N/kg; F1,13 = 4.936; P =.045; ηp2 = 0.275). This study provides preliminary evidence for the usefulness of TMG to detect fatigue-induced changes in contractile properties of the shoulder muscles in swimmers, in particular the latissimus dorsi and pectoralis major. [ABSTRACT FROM AUTHOR]

In this paper, we propose a new fixed point theorem in b-dislocated metric space which extend, generalize and unify some important results in literature. Also, we present an example to illustrate our main results. [ABSTRACT FROM AUTHOR]

The technique to broaden the scope of fixed point theory is to extend the class of spaces that have stronger conceptual frameworks than metric spaces. Therefore, this paper explores the introduction of novel metric spaces, namely, Branciari suprametric spaces, and investigates some of its fundamental topological properties. An illustration is provided to validate the newly defined idea of Branciari suprametric spaces. Further two intriguing, fixed point results are proved, and a corollary is presented as an implication of our main result. The following is a specification of the analogue of the rectangle inequality in Branciari suprametric spaces dB (τ,ι) ≤ dB (τ,ν)+dB(ν,σ)+dB(σ,ι) + μdB (τ,ν)dB(ν,σ)dB(σ,ι) for all t≠v, v≠σ and σ≠1. Furthermore, by employing the results obtained, the present study intends to provide an appropriate solution for the nonlinear fractional differential equations of the RiemannLiouville type. [ABSTRACT FROM AUTHOR]

This study aims to compare the differences in strength training at velocity of muscle contraction in 400-meter runners. The sample group consisted of 12 female athletes who participated in the Thailand National Sports competition qualifiers in 2023. The group was divided into two: the first group underwent strength training at a fast muscle contraction rate with 80 bpm, while the second group trained at a normal muscle contraction rate with 40 bpm. The training lasted for 8 weeks, and after a 2-week post-training period, both groups were tested by swapping strength training programs. They were tested for 400-meter speed, strength from finding the 1 RM of Leg curl, Leg extension, and Leg press measured in kilograms, and explosive power from Squat jump, Countermovement jump, and Long jump. The data collected was analyzed to find the average, standard deviation, and one-way ANOVA with a statistical significance level set at .05. From the research's results, it was found that percentage change muscle contraction rates differs significantly between the two strength training formats: one with fast muscle contraction and the other with normal-muscle contraction rate (1.04±0.02 and 1.02±0.02, respectively) at a significance level of .05. Additionally, the strength and explosive power percentage change also significantly differ between the two strength training formats. Therefore, based on this study, it is possible to utilize the fast muscle contraction rate strength training format to enhance the athletic performance of athletes. [ABSTRACT FROM AUTHOR]

When publishing Old Bulgarian chants, hymnologists almost always reconstruct the genitive inflection for the masculine and neuter singular of the full-form adjectives, ordinal numerals and participles in its most archaic form: -aego (or -аjego). However, the early acrostics contain only the contracted variant-ago. This contradiction is resolved in the present article by examining the syllabic structure of various original (not translated) Old Bulgarian chants, among which the four canons with 12-syllable verse have the greatest evidential value. The analyses show that the disciples of SS Cyril and Methodius used both uncontracted and contracted forms of the genitive ending. Taking this characteristic linguistic feature into account will lead to more accurate results of the versification studies on the most ancient Slavic hymnographic works. [ABSTRACT FROM AUTHOR]

This work presents a significant contribution to the field of mathematical analysis by introducing θ-Fℵ-contractions of Darbo-type. These newly introduced contractions serve as pivotal tools within our study. By employing these contractions, we systematically establish several pivotal fixed point theorems that allow us to guarantee the existence of fixed points in the Banach spaces. We construct particular examples in order to support the validity and effectiveness of our theoretical results. Moreover, we extend the utility of our established theorems by applying them to solve real-world problems. Specifically, we direct our attention to exploring the existence of solutions to the fractional order Lymphatic filariasis infection model.

Introduction. Being an integral part of the modern construction, concrete is a complex nonlinear material. The behaviour of concrete depends to a large extent on stress–strain state and loading history. Among the structures of newly constructed and reconstructed buildings, there are a large number of elements operating in the conditions of the triaxial stress–strain state, alternating and cyclic loading. A phenomenological material model used in the numerical methods can serve as a universal tool that allows to describe the behavior of concrete under such conditions. The aim of the research is to develop the concrete model that allows to simulate material behavior with sufficient accuracy under static short-term loading. The model should reflect the key features, which characterizes the behaviour of concrete and have an algorithm for regularizing the problem of localization of irreversible deformations.Materials and methods. This research is based on the analytical generalization and systematization of the data received from domestic and foreign sources devoted to the plasticity theory and fracture mechanics of concrete and reinforced concrete.Results. The model was implemented in the ANSYS finite-element software package, with the help of which it is possible to apply custom material models. Comparison of the laboratory and numerical results for concrete and reinforced concrete was made.Conclusions. The presented model allows to simulate behavior of concrete with substantial accuracy within the static short-term loading and reflects main features of the material behavior. To regularize the problem of localization of irreversible deformations, the model uses an approach based on the crack band theory. The values of all parameters required for the utilisation of the material model are presented.

Chronic venous disease (CVD) is a proqgressive and underestimated condition related to a vicious circle established by venous reflux and endothelial inflammation, leading to vein dilation and histology distortion, including loss of media tone. Sulodexide (SDX) is a drug restoring the glycocalyx that demonstrated endothelial protection and permeability regulation, together with anti-thrombotic and anti-inflammatory roles. In the lab it also exhibited vein contractility function. The aim of the present study was to show the possible role of endothelium and nitric oxide pathway on SDXs veno-contractile effect on human saphenous veins. The remnants of great saphenous vein (GSV) segments (n = 14) were harvested during coronary artery bypass graft surgery. They were dissected as endothelium-intact (n = 8) and denuded rings (n = 6). First, a viability test was carried out in bath with Krebs-Henseleit solution to investigate a control and basal tension value. After this, cumulative doses of SDX were applied to rings and contraction values were studied in endothelium-intact phenylephrine (PheE, 6 × 10-7 M) pre-contracted vein rings. Finally, endothelium-intact PheE pre-contacted vein rings were treated by nitric oxide synthase inhibitor Nω-nitro-L-arginine methyl ester (L-NAME, 10-4 M) for 10 min. Contraction protocol was applied, and contraction values were measured in cumulative doses of SDX. The same protocol was applied to endothelium-denuded vein rings to investigate the effect of SDX. Saphenous vein rings showed an increase in contraction to cumulative doses of SDX. In endothel-intact rings, KCL-induced contraction from 92.6% ± 0.3 to 112.9% ± 0.4 with cumulative SDX doses. However, SDX did not show any veno-contractile effect on endothel-denuded rings. In denuded rings contraction responses measured from 94.9% ± 0.3 to 85.2% ± 0.3 with increasing doses of SDX, indicating no significant change. Nitric oxide synthase inhibitor (L-NAME) prohibited the contraction response of the sulodexide in all dosages, indicating that the contractile function of SDX was mediated by endothelial derived nitric oxide. Results of endothel-intact and denuded rings with L-NAME showed a similar incline with denuded rings with SDX only. The results confirmed SDXs veno-contractile effect in human samples, by means of nitric oxide synthase pathways involvement.

Aims: As uterine extracellular pH decreases during the ischemic conditions of labor, but its effects on myometrial contraction are largely unknown, there is a need to elucidate its physiological effects and mechanisms of action. Furthermore, it is not known if any of the effects of extracellular acidification are affected by pregnancy, thus we also determined how gestation affects the response to acidification. Methods: Nonpregnant, mid‐, and term‐pregnant myometrial strips were obtained from humanely killed mice. Contractions were recorded under spontaneous, depolarized, and oxytocin‐stimulated conditions. The extracellular pH of the perfusate was changed from 7.4 to 6.9 or 7.9 in HEPES‐buffered physiological saline. Intracellular pH was measured using SNARF, and intracellular calcium was measured using Indo‐1. Statistical differences were tested using the appropriate t‐test. Results: Extracellular acidification significantly increased the frequency and amplitude of spontaneous contractions in pregnant, but not nonpregnant, myometrium, whereas alkalinization decreased contractions. Intracellular acidification, via Na‐butyrate, transiently increased force in pregnant tissue. Intracellular pH was gradually acidified when extracellular pH was acidified, but extracellular acidification increased contractility before any significant change in intracellular pH. If myometrial force was driven by oxytocin or high‐K depolarization, then extracellular pH did not further increase force. Intracellular calcium changes mirrored those of force in the spontaneously contracting pregnant myometrium, and if calcium entry was prevented by nifedipine, extracellular acidification could not induce a rise in force. Conclusion: Extracellular acidification increases excitability, calcium entry, and thus force in pregnant mouse myometrium, and this may contribute to increasing contractions during labor when ischemic conditions and acidemia occur. [ABSTRACT FROM AUTHOR]

In this paper, we investigate several new classes of multi-dimensional almost automorphic type sequences and focus on their applications to various difference equations involving Volterra difference equations. We provide many structural results, illustrative examples and open problems about the notion under consideration. [ABSTRACT FROM AUTHOR]

Two of the most well-known belief contraction operators are partial meet contractions (PMCs) and kernel contractions (KCs). In this paper we propose two new classes of contraction operators, namely the class of generalized partial meet contractions (GPMC) and the class of generalized kernel contractions (GKC), which strictly contain the classes of PMCs and of KCs, respectively. We identify some extra conditions that can be added to the definitions of GPMCs and of GKCs, which give rise to some interesting subclasses of those classes of functions, namely the classes of extensional and of uniform GPMCs/GKCs. In the context of contractions on belief sets the classes of partial meet contractions, uniform GPMCs and extensional GPMCs are all identical. Nevertheless, when considered as operations on belief bases, the class of uniform GPMCs coincides with the class of partial meet contractions, but the extensional GPMCs constitute a new kind of belief base contraction functions whose characterizing postulate of irrelevance of syntax is extensionality—the same postulate of irrelevance of syntax which occurs in the classical axiomatic characterization of partial meet contractions for belief sets—rather than the postulate of uniformity—which is the irrelevance of syntax postulate used in the axiomatic characterization for partial meet contractions on belief bases. Analogous results are obtained regarding the classes of extensional and of uniform GKCs. We present the interrelations in the sense of inclusion among all the new classes of operators presented in this paper and several well known classes of PMCs and of KCs. [ABSTRACT FROM AUTHOR]

This work presents a significant contribution to the field of mathematical analysis by introducing θ - F ℵ -contractions of Darbo-type. These newly introduced contractions serve as pivotal tools within our study. By employing these contractions, we systematically establish several pivotal fixed point theorems that allow us to guarantee the existence of fixed points in the Banach spaces. We construct particular examples in order to support the validity and effectiveness of our theoretical results. Moreover, we extend the utility of our established theorems by applying them to solve real-world problems. Specifically, we direct our attention to exploring the existence of solutions to the fractional order Lymphatic filariasis infection model. [ABSTRACT FROM AUTHOR]

Negative cumulative effects of lanthanides on the human body are well known; they are mainly related to the toxic effects of rare earth metals (REE) on muscle tissue. However, the effects of low concentrations of these metals on muscle are much less well studied. In our work, we identified an unusual stimulatory effect of low concentrations of europium (Eu3+) on spontaneous contractions of frog cardiac muscle atrial preparations. The aim of the present study was to investigate the stimulatory effect of europium (Eu3+) on the contraction of heart muscle atrial preparations, both normally and in the presence of the mitochondrial respiration inhibitor sodium azide (NaN3). The study was carried out using two experimental models: muscle preparations obtained from isolated atria of the frog Rana ridibunda heart and mitochondria isolated from the heart of male Wistar rats. As a result of these studies, it was found that Eu3+ at a concentration of 0.2 mM, at a temperature of 20°C, potentiated frog atrial contractions in situ, with an increase in both the amplitude and the maximum rate of increase in the strength of single spontaneous contractions. Spontaneous atrial contractions became more resistant to the effects of 1 mM NaN3. At the same time, Eu3+ did not affect the respiration of energized mitochondria, (activated by ADP (state 3) or 2,4-dinitrophenol (state 3UDNP)). The intensity of this respiration decreased under conditions of calcium loading of mitochondria regardless of the presence of Eu3+ in the medium. Thus, on the basis of these studies, it was concluded that Eu3+ ions at low concentration (0.2 mM) stimulate atrial contraction and have a positive inotropic effect. The stimulating effect of low concentration of Eu3+ on the heart can be explained by synergism in the action of Ca2+ and Eu3+ on calcium channels, stimulation of Ca2+-dependent processes in cardiomyocytes and absence of negative effect on mitochondrial respiration. [ABSTRACT FROM AUTHOR]

We obtain results on the existence and approximation of fixed points of enriched contractions in quasi-Banach spaces and thus extend the previous results for enriched contractions defined on Banach spaces [Berinde, V.; Păcurar, M. Approximating fixed points of enriched contractions in Banach spaces. J. Fixed Point Theory Appl. 22 (2020), no. 2, Paper No. 38, 10 pp.]. The theoretical results are illustrated by means of an appropriate example of enriched contraction on a quasi-Banach space which is not a Banach space and thus show that our new results are effective generalizations of the previous ones in literature. [ABSTRACT FROM AUTHOR]

Skeletal muscle mediates the beneficial effects of exercise, thereby improving insulin sensitivity and reducing the risk for type 2 diabetes. Current human skeletal muscle models in vitro are incapable of fully recapitulating its physiological functions especially muscle contractility. By supplementation of insulin-like growth factor 1 (IGF1), a growth factor secreted by myofibers in vivo, we aimed to overcome these limitations. We monitored the differentiation process starting from primary human CD56-positive myoblasts in the presence/absence of IGF1 in serum-free medium in daily collected samples for 10 days. IGF1-supported differentiation formed thicker multinucleated myotubes showing physiological contraction upon electrical pulse stimulation (EPS) following day 6. Myotubes without IGF1 were almost incapable of contraction. IGF1 treatment shifted the proteome toward skeletal muscle-specific proteins that contribute to myofibril and sarcomere assembly, striated muscle contraction, and ATP production. Elevated PPARGC1A, MYH7, and reduced MYH1/2 suggest a more oxidative phenotype further demonstrated by higher abundance of proteins of the respiratory chain and elevated mitochondrial respiration. IGF1-treatment also upregulated glucose transporter (GLUT)4 and increased insulin-dependent glucose uptake compared with myotubes differentiated without IGF1. To conclude, addition of IGF1 to serum-free medium significantly improves the differentiation of human myotubes that showed enhanced myofibril formation, response to electrical pulse stimulation, oxidative respiratory capacity, and glucose metabolism overcoming limitations of previous standards. This novel protocol enables investigation of muscular exercise on a molecular level. NEW & NOTEWORTHY: Human skeletal muscle models are highly valuable to study how exercise prevents type 2 diabetes without invasive biopsies. Current models did not fully recapitulate the function of skeletal muscle especially during exercise. By supplementing insulin-like growth factor 1 (IGF1), the authors developed a functional human skeletal muscle model characterized by inducible contractility and increased oxidative and insulin-sensitive metabolism. The novel protocol overcomes the limitations of previous standards and enables investigation of exercise on a molecular level. [ABSTRACT FROM AUTHOR]

Let G = (V , E) be a simple graph. A dominating set of G is a subset S ⊆ V such that every vertex not in S is adjacent to at least one vertex in S. The cardinality of a smallest dominating set of G , denoted by γ (G) , is the domination number of G. A dominating set S is called a super dominating set of G , if for every vertex u ∈ S ¯ = V − S , there exists v ∈ S such that N (v) ∩ S ¯ = { u }. The cardinality of a smallest super dominating set of G , denoted by γ sp (G) , is the super domination number of G. In this paper, we study super domination number of some graph classes and present sharp bounds for some graph operations. [ABSTRACT FROM AUTHOR]