State Equilibrium Research Articles

Myosin and tropomyosin-troponin complementarily regulate thermal activation of muscles.

Contraction of striated muscles is initiated by an increase in cytosolic Ca2+ concentration, which is regulated by tropomyosin and troponin acting on actin filaments at the sarcomere level. Namely, Ca2+-binding to troponin C shifts the "on-off" equilibrium of the thin filament state toward the "on" state, promoting actomyosin interaction; likewise, an increase in temperature to within the body temperature range shifts the equilibrium to the on state, even in the absence of Ca2+. Here, we investigated the temperature dependence of sarcomere shortening along isolated fast skeletal myofibrils using optical heating microscopy. Rapid heating (25 to 41.5°C) within 2 s induced reversible sarcomere shortening in relaxing solution. Further, we investigated the temperature-dependence of the sliding velocity of reconstituted fast skeletal or cardiac thin filaments on fast skeletal or β-cardiac myosin in an in vitro motility assay within the body temperature range. We found that (a) with fast skeletal thin filaments on fast skeletal myosin, the temperature dependence was comparable to that obtained for sarcomere shortening in fast skeletal myofibrils (Q10 ∼8), (b) both types of thin filaments started to slide at lower temperatures on fast skeletal myosin than on β-cardiac myosin, and (c) cardiac thin filaments slid at lower temperatures compared with fast skeletal thin filaments on either type of myosin. Therefore, the mammalian striated muscle may be fine-tuned to contract efficiently via complementary regulation of myosin and tropomyosin-troponin within the body temperature range, depending on the physiological demands of various circumstances.

Water vapor sorption and transport in carbon molecular sieve membranes

Carbon Molecular Sieve (CMS) membranes have been extensively studied for gas separations. Many gas separation applications involve humidified streams, but reports on water vapor transport in CMS membranes are limited. In this study, water permeability, diffusivity, and solubility were determined as a function of water activity for CMS membranes. Water transport properties of membranes synthesized at different pyrolysis temperatures (550 °C and 800 °C) and with different polyimide precursors were examined. Water sorption followed Type V isotherms as previously observed for the adsorption of water in microporous carbons. Water permeability was much higher at all water activity values for CMS samples prepared at lower pyrolysis temperature. Water permeabilities as a function of water activity of the three different polyimides pyrolyzed at 800 °C were very similar. Water permeability of CMS membranes was high compared to many other polymeric materials, showing potential for dehydration applications. Finally, the steady-state water vapor diffusivity (Dss), estimated from steady state permeability and equilibrium sorption measurements, was compared to the experimental transient diffusivity (D), matching reasonably well.

Structurally Constrained Evolutionary Algorithm for the Discovery and Design of Metastable Phases.

Metastable materials are abundant in nature and technology, showcasing remarkable properties that inspire innovative materials design. However, traditional crystal structure prediction methods, which rely solely on energetic factors to determine a structure's fitness, are not suitable for predicting the vast number of potentially synthesizable phases that represent a local minimum corresponding to a state in thermodynamic equilibrium. Here, we present a new approach for the prediction of metastable phases with specific structural features and interface this method with the XtalOpt evolutionary algorithm. Our method relies on structural features that include the local crystalline order (e.g, the coordination number or chemical environment), and symmetry (e.g, Bravais lattice and space group) to filter the breeding pool of an evolutionary crystal structure search. The effectiveness of this approach is benchmarked on three known metastable systems: XeN8, with a two-dimensional polymeric nitrogen sublattice, brookite TiO2, and a high pressure BaH4 phase, which was recently characterized. Additionally, a newly predicted metastable melaminate salt, P1̅ WC3N6, was found to possess an energy that is lower than that of two phases proposed in a recent computational study. The method presented here could help in identifying the structures of compounds that have already been synthesized, and in developing new synthesis targets with desired properties.

A novel zinc finger transcription factor, BcMsn2, is involved in growth, development, and virulence in Botrytis cinerea.

Reactive oxygen species (ROS) are important for plant defense against fungal attack. As a necrotrophic fungus, Botrytis cinerea can exploit ROS that originated from both sides of the host and pathogen during interaction to facilitate its infestation. Meanwhile, B. cinerea needs to exert an efficient oxidative stress responsive system to balance the intracellular redox state when encountering deleterious ROS levels. However, the machinery applied by B. cinerea to cope with ROS remains obscure. Herein, we investigated the role of the transcription factor BcMsn2 in regulating B. cinerea redox homeostasis. Disruption of the BcMsn2 gene severely impaired vegetative growth, sclerotium formation, conidial yield, and fungal virulence. The intracellular oxidative homeostasis of the ∆bcmsn2 mutant was disrupted, leading to significantly elevated levels of ROS and reduced activities of enzymes closely associated with oxygen stress, such as catalase (CAT) and superoxide dismutase (SOD). RNA-Seq and qRT-PCR analyses showed remarkable downregulation of the expression of several genes encoding ROS scavenging factors involved in maintaining the redox homeostasis in ∆bcmsn2, suggesting that BcMsn2 functions as a transcriptional regulator of these genes. Our findings indicated that BcMsn2 plays an indispensable role in maintaining the equilibrium of the redox state in B. cinerea, and intracellular ROS serve as signaling molecules that regulate the growth, asexual reproduction, and virulence of this pathogen.

Discrete-time layered-network epidemics model with time-varying transition rates and multiple resources

This paper studies a discrete-time time-varying multi-layer networked SIWS (susceptible-infected-water-susceptible) model with multiple resources under both single-virus and competing multi-virus settings. Besides the human-to-human interaction, we also consider that the disease can diffuse on different types of medium. We use resources to refer to any media through which the pathogen of a virus can spread, and do not restrict the resource only to be water. In the single-virus case, we give a full analysis of the system’s behaviour related to its healthy state and endemic equilibrium. In the multi-virus case, we show analytically that different equilibria appear driven by the competition among all viruses. We also show that some analytical results of the time-invariant system can be expanded into time-varying cases. Finally, we illustrate the results through some simulations.

Economically optimised target state of uneven-aged forest management for main forest types in Slovakia

Abstract The study presented a bioeconomic modelling approach for an uneven-aged mixed forest management planning. Regression models for transition (increment), and ingrowth (regeneration) used the National Forest Inventory (NFI) of Slovakia and regional inventory data. Mortality was based on salvage logging records. Models were specific for five tree species within three forest types (FT) (oak with hornbeam and beech, beech, mixed fir-beech-spruce). Net timber prices were calculated with regard to stem quality. Tree growth depended on crown characteristics. The regression models were adjusted to three main geobiotope (GBT) sites per FT. Forest growth was simulated with the density-dependent stand-level matrix transition model. Financial optimisation of harvest was sensitive to an interest rate. Long-time optimisation stabilised in a steady state equilibrium characterised by a stable diameter distribution. Target diameters were specific for site and tree species, and were highest for fir, a dense crown, a good stem quality, and a lower interest rate. Standing timber volume varied from 150 m3 ha–1 (oak forests, 2% interest rate) to 400 m3 ha–1 (beech and fir-beech-spruce forests, 0.5% interest rate). Harvested volume varied from 38 to 93 m3 ha–1 per 10 years, stand basal area (ba) varied from 19 to 36 m2 ha–1 depending on the site, timber price, and interest rate. The discussion pointed out that the relative low volume of the oak FT resulted from the light-demanding characteristics of oak. The mean of oak mosaic structures was lower compared to the high level of more storeys present in the single tree selection structures in beech and mixed fir-beech-spruce forests.

ПРОЦЕССУАЛЬНОЕ ФОРМИРОВАНИЕ НОРМЫ В СИСТЕМЕ ОБЩЕСТВЕННЫХ ОТНОШЕНИЙ

The article deals with the problem of social normality, which is actualized in the conditions of a communicative and information society. It is quite justifi ed that in modern realities, the study of the role of the norm in human behavioral strategies is the most relevant. This article is based on the assumption that the norm cannot be reduced to a set of rules of behavior as an external regulator of human activity. In the traditions of psychoanalysis and the phenomenological school, it is proposed to consider the norm in the unity of intentionality and rationality. In a comparative analysis of the conclusions of psychological and sociological sciences, it is determined that the norm is a mechanism for motivating activity. The possibility of the evolution of the norm from recognition as an external stimulus to a factor of internal action is revealed. The approaches to the norm as a form of state equilibrium of public relations are analyzed. Particular attention is paid to the state of the norm as a combination of hypothetical punishment and the degree of inner sensitivity of a person to the norm. An attempt was made to analyze the thesis about the unconditional nature of some, in particular, using the example of morality. In this regard, a critical section of modern classifi cations of normative components is given. The theoretical consequences of singling out regulation as an independent part of standards were traced. The psychic nature of social normality has been proven. It is shown that the norm can be considered as a mechanism of human changes. The importance of taking into account the norm in the processes of pleasure-without pleasure is noted.

A study of non-equilibrium wave groups in two-phase flow in high-contrast porous media with relative permeability hysteresis

Non-equilibrium models are applicable in various physical situations, including phase transitions, hysteresis, and chemical reactions, among others. To model the dynamics of such phenomena, partial differential equations are employed with source terms, as seen in Eq. (1.1). This work focuses on situations where we connect states in equilibrium while allowing for non-equilibrium times. In our model, we model non-equilibrium through relaxation. The source term, in this case, acts as an attractor, and the model’s dynamics allow only a small-time far from equilibrium. We use this theory to model a two-equation system in a two-phase fluid in porous media, where different permeabilities of the flow lead to hysteresis phenomena. We show several examples and study the Riemann solution to gain a better understanding of the solution. We investigate the interplay between nonlinear wave groups of water–oil saturation with different permeabilities in the non-wetting phase and the high-contrast heterogeneity of the porous medium in two-space dimensions. This phenomenon is described by a coupled set of time-dependent partial differential equations of hyperbolic–parabolic–elliptic mixed type. We present and discuss a new projection method with relaxation to obtain 1D-analytical Riemann solutions in an idealized homogenized medium, and we use this solution to validate our numerical method. The primary components of obtaining these solutions are shocks, rarefactions, and bifurcations. We obtain 2D-numerical solutions using an operator splitting approach based on physics, highlighting the discretization methods used. We provide robust analytical–numerical examples to verify the theory and illustrate the approach’s capabilities. In particular, we discuss the 1D-2D behavior of wave groups in situations driven by water–oil infiltration problems of permeable reservoir rocks.

What role public debt plays to moderate the influence of natural resources on financial development? Appraising Resource-Curse Hypothesis in MENA Region

A sound financial structure is one of the imperative macroeconomic goals for developed and developing ones, particularly for resource-abundant countries, which are more vulnerable due to the unexpected shock of COVID-19 and experiencing the financial resource curse (FRC). The literature has extensively discussed the assimilation of natural resources (NR) into a blessing or curse; however, little is known concerning the FRC hypothesis through integrating public debts (PD). Therefore, the present research scrutinizes the FRC in the Middle East and North African (MENA) countries by considering the PD, NR, institutional quality (IQ), and financial development (FD) in an integrating framework from 2001 to 2020. The study employs a cross-section augmented distributed lag (CS-ARDL) estimator to address the concerns of cross-section dependency and slope heterogeneity. The long-run empirical findings elucidate that NR significantly reduces FD and affirms the FRC hypothesis, while IQ positive promotes the FD in the MENA region. Another pertinent factor, PD reduces FD significantly, and the moderating impact of PD through NR reveals the inverse association with FD. Additionally, consistent findings are investigated in the short run with a smaller coefficient magnitude, and the cointegrating term converges towards the steady state equilibrium with a 29.4% adjustment rate in any diverging situation. Similar empirical outcomes are echoed from the alternative panel techniques, and panel causality testing indicates the bi-directional causality among all model variables except IQ and FD. Overall results provide valuable policy implications to the MENA region that should empower the IQ levels in mitigating the adverse impacts of FRC.

Dephasing effects on quantum correlations and teleportation in presence of state dependent bath

Quantum information protocols are often designed in the ideal situation with no decoherence. However, in real setup, these protocols are subject to the decoherence and thus reducing fidelity of the measurement outcome. In this work, we analyze the effect of state-dependent bath on the quantum correlations and the fidelity of a single qubit teleportation. We model our system-bath interaction as qubits interacting with a common bath of bosons, and the state dependence of the bath is generated through a projective measurement on the joint state in thermal equilibrium. The analytic expressions for the time evolution of entanglement, discord and average fidelity of quantum teleportation are calculated. It is shown that due to the presence of initial system-bath correlations, the system maintains quantum correlations for long times. Furthermore, due to the presence of finite long-time entanglement of the quantum channel, the average fidelity is shown to be higher than its classical value.

Temperature-Dependent Modulation of Short-Wave-Infrared Light Transparency Based on Associated Structures of a Liquescent Nickel(III) Complex.

A liquescent bis(malononitriledithiolato)nickel(III) complex with a bis(methoxyethyl)imidazolium cation, 1[Ni(mnt)2 ], exhibits three-stage thermochromic modulation of transparency/absorption in the short-wave-infrared (SWIR) region (1000-2500nm), driven by associated structural changes. Upon heating, the electronic spectra of 1[Ni(mnt)2 ] in the SWIR region shift to shorter wavelengths accompanying with the solid-liquid phase transition at 76°C. Further heating to over 109°C induces a second transition of the electronic spectra, characterized by a blue-shift of the SWIR absorption in the liquid phase. The results of temperature-dependent electronic spectra and magnetic susceptibility indicated that the thermochromic changes can be attributed to the two-step dissociation of the associated structures of [Ni(mnt)2 ]- , occurring during the solid-liquid phase transition and the shift of dimer-monomer equilibrium in the liquid state. These changes can be visualized using an SWIR imaging camera under appropriate SWIR lights.

Set Stability of Probabilistic Logical Networks and Its Application to State-Based Games

Set stability of probabilistic multi-valued logical networks (PMLNs) is investigated in this paper. Different from the existing concepts of set stability, the set stability considered in this paper is starting from a given initial set to a given destination set. Firstly, an algebraic expression of PMLNs is established by using the semi-tensor product method. Then, a matrix method is proposed to obtain the largest invariant subset contained in the given destination set. Based on the invariant subset, a necessary and sufficient condition for set stability from a given initial set to a destination set is presented. Finally, application to state-based games is considered, and the criterion proposed for PMLNs is applied to verify the stability of recurrent state equilibrium.

Light impurities: equilibrium, transport and density profiles in tokamak and stellarator plasmas

The density profiles of light impurities observed in recent decades in a relatively wide variety of experiments on tokamaks and stellarators are analyzed and modeled based on the concept of self-consistent equilibrium and transport of impurity charge states (Shurygin 2020 Nuclear Fusion 60 046001). The emphasis is on the formation of charge-radial equilibrium and its invariant properties affecting transport and density profile. The impurity invariant equilibrium arises due to random compatible charge-radial variations, linking the impurity motion into a general ergodic (Markovian) process governed by a matrix of final probabilities. More than 60 profiles of helium, boron and carbon with central accumulation, flat and hollow were accurately reproduced by invariant dimensionless transport functions. It is shown that the leading processes determining the formation of impurity invariant density profiles in stationary plasma are the processes of ionization-recombination, and not the transport of particles. Successive variations in the hollow density profiles of helium, boron, and carbon observed in experiments can be described as successive invariant profile changes in the recombination rate profiles. The invariant particle diffusive-convective profiles can be calculated directly from the impurity density profiles. A general empirical formula for equilibrium constant of light impurities was proposed.

The biophysical modelling of the human organism by the biophysical point of view

Biophysics is searching for, dealing of and teaching the forms of the connections between the inanimate nature, the living world and the spiritual life, the applicability limits of their own laws in the other medium, their common mutual interactions. Biophysics undertakes, by means of mathematics, desc¬ription of the so-called homeostasis established by the dynamic equilibrium of the common normal state of the nature, the living world and that of the spirit. According to system theory, the human is a system, the five subsystems of which (digestive, respiratory, circulatory, exc¬retory, and reproductive) formed during phylogenetic develop¬ment short are addressed in this article. In living organisms, structure and function can be con¬sidered as a symbiosis: structure defines function, and function influences, modifies and develops the struc¬ture, which again enables a higher level function and activity. Many long-lasting structural perturbations result in func¬tional perturbations and similarly, long-lasting functional perturbations result in structural perturbations. This perturbation symbiosis is represented by the large group of psychological perturbations.

The Amount ofZeaxanthin Epoxidase But Not the Amount ofViolaxanthin De-Epoxidase Is a Critical Determinant ofZeaxanthin Accumulation inArabidopsis thaliana andNicotiana tabacum.

The generation of violaxanthin (Vx) de-epoxidase (VDE), photosystem II subunit S (PsbS) and zeaxanthin (Zx) epoxidase (ZEP) (VPZ) lines, which simultaneously overexpress VDE, PsbS and ZEP, has been successfully used to accelerate the kinetics of the induction and relaxation of non-photochemical quenching (NPQ). Here, we studied the impact of the overexpression of VDE and ZEP on the conversion of the xanthophyll cycle pigments in VPZ lines of Arabidopsis thaliana and Nicotiana tabacum. The protein amount of both VDE and ZEP was determined to be increased to about 3- to 5-fold levels of wild-type (WT) plants for both species. Compared to WT plants, the conversion of Vx to Zx, and hence VDE activity, was only marginally accelerated in VPZ lines, whereas the conversion of Zx to Vx, and thus ZEP activity, was strongly increased in VPZ lines. This indicates that the amount of ZEP but not the amount of VDE is a critical determinant of the equilibrium of the de-epoxidation state of xanthophyll cycle pigments under saturating light conditions. Comparing the two steps of epoxidation, particularly the second step (antheraxanthin to Vx) was found to be accelerated in VPZ lines, implying that the intermediate Ax is released into the membrane during epoxidation by ZEP.

Spatial-temporal variability: characterisation of a beach system using high resolution radar data

Intertidal areas experience a series of complex dynamic processes that affect beach morphology. Many of these processes are difficult to monitor, particularly due to the limited availability of high-resolution data. This study utilises high resolution radar-derived DEMs obtained through the temporal waterline method high resolution to perform a spatio-temporal analysis of beach morphology over the macrotidal nearshore of Rossall Beach, UK. Beach elevation changes are characterized, providing new insights into the morphological processes from fortnightly to seasonal time scales. The results of this analysis draw focus to the short-term variations in beach morphology and their contributions to long-term change. Observation of spatio-temporal variation displayed an intertidal system in a seasonal steady state equilibrium, somewhat dominated by elevation changes within the spring and summer months. Furthermore, the upper-intertidal zone displays evidence of continuing accretion. Though the analysis within this study is mostly explorative, it shows the potential of radar data for autonomous monitoring and spatio-temporal characterization of the coast. This enables coastal managers and stakeholders to build a long-term picture of the coastline, reducing vulnerability to coastal hazards and building resilience.

Algorithmic criteria for the validity of quasi-steady state and partial equilibrium models: the Michaelis-Menten reaction mechanism.

We present "on the fly" algorithmic criteria for the accuracy and stability (non-stiffness) of reduced models constructed with the quasi-steady state and partial equilibrium approximations. The criteria comprise those introduced in Goussis (Combust Theor Model 16:869-926, 2012) that addressed the case where each fast time scale is due to one reaction and a new one that addresses the case where a fast time scale is due to more than one reactions. The development of these criteria is based on the ability to approximate accurately the fast and slow subspaces of the tangent space. Their validity is assessed on the basis of the Michaelis-Menten reaction mechanism, for which extensive literature is available regarding the validity of the existing various reduced models. The criteria predict correctly the regions in both the parameter and phase spaces where each of these models is valid. The findings are supported by numerical computations at indicative points in the parameter space. Due to their algorithmic character, these criteria can be readily employed for the reduction of large and complex mathematical models.

Myoglobin content and oxidative status to understand meat products’ color: Phenomenological based model

Meat color is attributed to myoglobin concentration and redox state. Myoglobin is a water-soluble hemoprotein with iron in its prosthetic group, which defines myoglobin’s redox state via its valence state and ligand linked to the free coordination site. In fresh meat, myoglobin can be in one of three states in dynamic equilibrium: deoxymyoglobin, oxymyoglobin, and metmyoglobin. Myoglobin can chemically interact with numerous components in meat products, affecting its redox state. These structural alterations in myoglobin caused by processing conditions will affect its thermal stability and consequently meat product color. Presently, cured meat products are made with sodium nitrite, a curing agent that reacts with myoglobin in meat, forming nitrosomyoglobin, a stable compound that gives the final meat product a distinctive pink color. This work proposes a mathematical model for understanding myoglobin structural changes during the production of a cured meat product. Because of the phenomenological structure of the established model, valuable knowledge is obtained, allowing new possibilities to be explored in the color of meat products while considering the chemical state of myoglobin. The proposed phenomenological model is validated with an error of roughly 10%.

Functional regulation of an intrinsically disordered protein via a conformationally excited state.

A longstanding goal in the field of intrinsically disordered proteins (IDPs) is to characterize their structural heterogeneity and pinpoint the role of this heterogeneity in IDP function. Here, we use multinuclear chemical exchange saturation (CEST) nuclear magnetic resonance to determine the structure of a thermally accessible globally folded excited state in equilibrium with the intrinsically disordered native ensemble of a bacterial transcriptional regulator CytR. We further provide evidence from double resonance CEST experiments that the excited state, which structurally resembles the DNA-bound form of cytidine repressor (CytR), recognizes DNA by means of a "folding-before-binding" conformational selection pathway. The disorder-to-order regulatory switch in DNA recognition by natively disordered CytR therefore operates through a dynamical variant of the lock-and-key mechanism where the structurally complementary conformation is transiently accessed via thermal fluctuations.

Identification of soil strength parameters for assessing stability of a sliding slope

The article presents the results of assessment of stability of the sliding slope, which was performed with the use methods of limit equilibrium and numerical modeling of the stress-strained state of the slope soils. It is obvious that usage of soil strength parameters c and φ without their clarification (identification) can lead to an overestimation of the value of the safety factor and thus slopes will be mistakenly classified as stable. The choice of the correct soil parameters is a key factor in the calculations in order to obtain calculated slip surfaces close to the actually recorded ones. The object of the study is an artificial landscape massif located on a slope. The site has the shape of an amphitheater in the form of stairs that occupy half of the entire area in the central part and sloping surfaces at the edges. The radius of the upper face is 42.20 m, the lower face is 21.95 m. The total number of steps is six. The absolute mark of the first step is 289.00 m, the mark of the bottom of the amphitheater is 280.00 m. During construction works related to the formation of a stepped landform of the landmass, a landslide happened on the territory of the object, therefore, during the calculation of the stability of the slope, the main task was to choose the correct values of c and φ so that the modeling results coincide with the data of field observations and on the basis of these data, it would be later on possible to make reasonable engineering decisions about measures to stabilize the slope and ensure its stability at the stage of operation. To assess stability of the slope, a series of calculations was performed in the initial (natural) state and in the current state with characteristics changed due to wetting. Soil parameters were identified on the basis of engineering and geological investigations. As a result of specifying the strength parameters, the coefficients of the stability were determined, which reflect the ultimate equilibrium of the slope, which corresponds to the real picture in the area. For numerical modeling, the initial stability coefficients had the following values: for 3 steps K=2.396; with complete excavation K=1.428. After adjusting c and φ, they decreased by 2.3 times and 1.4 times, respectively. A similar situation occurred for the assessment of slope stability using the limit equilibrium method. For three steps, the initial coefficient K=2.70 decreased by 2.5 times; with complete excavation, K=1.54 decreased by 1.5 times.