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Once a baseline resolution to the question of Palestine, the two-state solution has become contested after decades of failed negotiation and renewed support for a one-state solution. This study measures Palestinian university students' understandings of these different solutions through a representative survey. Results indicate that despite being unconvinced by it, the majority of respondents prefer a two-state solution, although their conception of its specificities differs to that of the Palestinian Authority. Most respondents held unclear ideas of the meaning of the one-state solution. Finally, a model based on analysis of this data explains the reasons and circumstances behind students' preferences. [ABSTRACT FROM AUTHOR]

Abstract It has been a long time to analyze the stability of micro-grids. However, present researches are for small signal (or linear) stability analysis. Such system loses its stability after passing Hopf branches that can be divided into subcritical or super-critical. In the subcritical branch conditions, the stable area defined by small signal stability analysis may have an unstable limit cycle. The algorithm takes the congestion and non-congestion performances of the communication network into full account. The controller will be adaptive to the changes of communication network state with real-time estimation of network state and by using the gain scheduling technology. Additionally, the mobile average threshold estimator is used. Methods for selecting the buffer length and threshold value are provided in the congested/non-congested PLC communication network. Lastly, analysis of the micro-grid stability margin and validation of the algorithm effectiveness are performed. [ABSTRACT FROM AUTHOR]

Protein folding is a complex physicochemical process whereby a polymer of amino acids samples numerous conformations in its unfolded state before settling on an essentially unique native three-dimensional (3D) structure. To understand this process, several theoretical studies have used a set of 3D structures, identified different structural parameters, and analyzed their relationships using the natural logarithmic protein folding rate (ln(k f )). Unfortunately, these structural parameters are specific to a small set of proteins that are not capable of accurately predicting ln(k f ) for both two-state (TS) and non-two-state (NTS) proteins. To overcome the limitations of the statistical approach, a few machine learning (ML)-based models have been proposed using limited training data. However, none of these methods can explain plausible folding mechanisms. In this study, we evaluated the predictive capabilities of ten different ML algorithms using eight different structural parameters and five different network centrality measures based on newly constructed datasets. In comparison to the other nine regressors, support vector machine was found to be the most appropriate for predicting ln(k f ) with mean absolute differences of 1.856, 1.55, and 1.745 for the TS, NTS, and combined datasets, respectively. Furthermore, combining structural parameters and network centrality measures improves the prediction performance compared to individual parameters, indicating that multiple factors are involved in the folding process., Competing Interests: Declaration of competing interest The author declares no conflict of interests., (Copyright © 2023 The Authors. Published by Elsevier Ltd.. All rights reserved.)

We present an analysis of atomistic MD simulations of glycerol that give evidence of two distinct dynamic states at short times in a realistic molecular liquid and show that these are associated with hopping at temperatures well above the melting temperature and the mode coupling critical temperature, T c . We find that this hopping mode contributes significantly to transport, even at these high temperatures. The simulations support our previous interpretation of incoherent quasi-elastic neutron scattering (QENS) where we determined that, on a 1 ps timescale and over a very wide temperature range, molecules are either highly confined or free to undergo relatively large scale motion. [ABSTRACT FROM AUTHOR]

Abstract: Three-state unfolding profiles obtained using spectroscopic techniques can generally be fitted using two-state equation, making it difficult to make a distinction between two-state and three-state transition. Simulations of fluorescence intensity–temperature profile for a three-state transition and subsequent fitting using two-state equation suggest that it is easier to decipher three-state nature of protein unfolding from temperature induced unfolding profile rather than denaturant induced unfolding profile. However, there are some extreme cases where it is difficult to predict the three-state transition even from temperature induced protein unfolding profiles. The simulation and the analysis of unfolding data of bovine serum albumin in the absence and presence of sodium dodecyl sulfate suggest that the addition of a fluorescence quencher helps in differentiating a two-state model with three-state model in such extreme cases. In addition, it helps to distinguish two different three-state models, one with higher first enthalpy ΔH m1 and other with lower ΔH m1. [Copyright &y& Elsevier]

The two-state current conduction phenomenon in \Al_2\O_3/\SiO_2/\SiC stacked structure was investigated by varying the process of dielectric preparation. All the devices exhibited obvious two-state current conduction behavior under I\--V measurements. The threshold voltage of trap-assisted tunneling current conduction in the devices with \Al_2\O_3 layer prepared by \HNO_3 oxidation occurred at a smaller voltage than that by anodization; additionally, the former could be reset after positive bias stress with very small reset current but the latter could not. Meanwhile, the sample in \SiO_2 formation without UV light illumination exhibited faster electrical reset speed than that with UV light illumination. Both of endurance and retention characteristics were examined. The results show that different dielectric layer preparations strongly affect the characteristics of two-state current conduction in device with \Al_2\O_3/\SiO_2/\SiC stacked structure. [ABSTRACT FROM PUBLISHER]

The ability to determine conformational parameters of protein-folding landscapes is critical for understanding the link between conformation, function, and disease. Monitoring hydrogen exchange (HX) of labile protons at equilibrium enables direct extraction of thermodynamic or kinetic landscape parameters in two limiting extremes. Here, we establish a quantitative framework for relating HX behavior to landscape. We use this framework to demonstrate that the range of predicted global HX behavior for the majority of a set of characterized two-state proteins under near-native conditions does not readily span between both extremes. For most, stability may be quantitatively determined under physiological conditions, with semiquantitative boundaries on kinetics additionally determined using modest experimental perturbations to shift HX behavior. The framework and relationships derived in the simple context of two-state global folding highlight the importance of understanding HX across the entire continuum of behavior, in order to apply HX to map landscapes. [ABSTRACT FROM AUTHOR]

Abstract: The mobility of particles is generally lowered by the presence of a confining medium, both because of geometrical effects, and because of the interactions with the confining surfaces, especially when the latter are charged. The water/mineral interface plays a central role in the dynamics of ions. The ionic mobility in clays is often understood as an interplay between the diffusion of mobile ions and their possible trapping at the mineral surfaces. We describe how to build a two-state diffusion–reaction scheme from the microscopic dynamics of ions, controlled by their interaction with a mineral surface. The starting point is an atomic description of the clay interlayer using molecular simulations. These provide a complete description of the ionic dynamics on short time and length scales. Using the results of these simulations, we then build a robust mesoscopic (Fokker–Planck) description. In turn, this mesoscopic description is used to determine the mobility of the ions in the interlayer. These results can then be cast into a diffusion–reaction scheme, introducing in particular the fraction of mobile ions, or equivalently the distribution coefficient . This coefficient is of great importance in characterizing electrokinetic phenomena in porous materials. [Copyright &y& Elsevier]

Microtubules (MT) are composed of 13 protofilaments, each of which is a series of two-state tubulin dimers. In the MT wall, these dimers can be pictured as “lattice” sites similar to crystal lattices. Based on the pseudo-spin model, two different location states of the mobile electron in each dimer are proposed. Accordingly, the MT wall is described as an anisotropic two-dimensional (2D) pseudo-spin system considering a periodic triangular “lattice”. Because three different “spin-spin” interactions in each cell exist periodically in the whole MT wall, the system may be shown to be an array of three types of two-pseudo-spin-state dimers. For the above-mentioned condition, the processing of quantum information is presented by using the scheme developed by Lloyd. [ABSTRACT FROM AUTHOR]

Abstract: The 37-residue Formin-binding protein, FBP28, is a canonical three-stranded β-sheet WW domain. Because of its small size, it is so insensitive to chemical denaturation that it is barely possible to determine accurately a denaturation curve, as the transition spans 0–7 M guanidinium hydrochloride (GdmCl). It is also only marginally stable, with a free energy of denaturation of just 2.3 kcal/mol at 10 °C so only small changes in energy upon mutation can be tolerated. But these properties and relaxation times for folding of 25 μs–400 μs conspire to allow the rapid acquisition of accurate and reproducible kinetic data for Φ-analysis using classical temperature-jump methods. The transition state for folding is highly polarized with some regions having Φ-values of 0 and others 1, as readily seen in chevron plots, with Φ-values of 0 having the refolding arms overlaying and those of 1 the unfolding arms superimposable. Good agreement is seen with transition state structures identified from independent molecular dynamics (MD) simulations at 60, 75, and 100 °C, which allows us to explore further the details of the folding and unfolding pathway of FBP28. The first β-turn is near native-like in the transition state for folding (experimental) and unfolding (MD and experiment). The simulations show that there are transient contacts between the aromatic side-chains of the β-strands in the denatured state and that these interactions provide the driving force for folding of the first β-hairpin of this three-stranded sheet. Only after the backbone hydrogen bonds are formed between β1 and β2 does a hydrogen bond form to stabilize the intervening turn, or the first β-turn. [Copyright &y& Elsevier]

The folding of naturally occurring, single-domain proteins is usually well described as a simple, single-exponential process lacking significant trapped states. Here we further explore the hypothesis that the smooth energy landscape this implies, and the rapid kinetics it engenders, arises due to the extraordinary thermodynamic cooperativity of protein folding. Studying Miyazawa-Jernigan lattice polymers, we find that, even under conditions where the folding energy landscape is relatively optimized (designed sequences folding at their temperature of maximum folding rate), the folding of protein-like heteropolymers is accelerated when their thermodynamic cooperativity is enhanced by enhancing the nonadditivity of their energy potentials. At lower temperatures, where kinetic traps presumably play a more significant role in defining folding rates, we observe still greater cooperativity-induced acceleration. Consistent with these observations, we find that the folding kinetics of our computational models more closely approximates single-exponential behavior as their cooperativity approaches optimal levels. These observations suggest that the rapid folding of naturally occurring proteins is, in part, a consequence of their remarkably cooperative folding. [ABSTRACT FROM AUTHOR]

Abstract: A Markovian dichotomic system driven by a deterministic time-periodic force is analyzed in terms of the statistical properties of the switching events between the states. The consideration of the counting process of the switching events leads us to define a discrete phase. We obtain expressions for the instantaneous output frequency and phase diffusion associated to the dichotomic process, as well as for their cycle averages. These expressions are completely determined by the rates of escape from both states. They are a convenient starting point for the study of the stochastic frequency and phase synchronization in a wide range of situations (both classical and quantum) in which two metastable states are involved. [Copyright &y& Elsevier]

Recent years have seen the publication of both empirical and theoretical relationships predicting the rates with which proteins fold. Our ability to test and refine these relationships has been limited, however, by a variety of difficulties associated with the comparison of folding and unfolding rates, thermodynamics, and structure across diverse sets of proteins. These difficulties include the wide, potentially confounding range of experimental conditions and methods employed to date and the difficulty of obtaining correct and complete sequence and structural details for the characterized constructs. The lack of a single approach to data analysis and error estimation, or even of a common set of units and reporting standards, further hinders comparative studies of folding. In an effort to overcome these problems, we define here a 'consensus' set of experimental conditions (25°C at pH 7.0, 50 mM buffer), data analysis methods, and data reporting standards that we hope will provide a benchmark for experimental studies. We take the first step in this initiative by describing the folding kinetics of 30 apparently two-state proteins or protein domains under the consensus conditions. The goal of our efforts is to set uniform standards for the experimental community and to initiate an accumulating, self-consistent data set that will aid ongoing efforts to understand the folding process. [ABSTRACT FROM AUTHOR]

In the last couple of years, there has been increasing debate as to the presence and role of intermediate states on the folding pathways of several small proteins, including the 76-residue protein ubiquitin. Here, we present detailed kinetic studies to establish whether an intermediate state is ever populated during the folding of this protein. We show that the differences observed in previous studies are attributable to the transient aggregation of the protein during folding. Using a highly soluble construct of ubiquitin, which does not aggregate during folding, we establish the conditions in which an intermediate state is sufficiently stable to be observed by kinetic measurements. [Copyright &y& Elsevier]

We compare the folding of representative members of a protein superfamily by experiment and simulation to investigate common features in folding mechanisms. The homeodomain superfamily of three-helical, single-domain proteins exhibits a spectrum of folding processes that spans the complete transition from concurrent secondary and tertiary structure formation (nucleation-condensation mechanism) to sequential secondary and tertiary formation (framework mechanism). The unifying factor in their mechanisms is that the transition state for (un)folding is expanded and very native-like, with the proportion and degree of formation of secondary and tertiary interactions varying. There is a transition, or slide, from the framework to nucleation-condensation mechanism with decreasing stability of the secondary structure. Thus, framework and nucleation-condensation are different manifestations of an underlying common mechanism. [ABSTRACT FROM AUTHOR]

We address the importance of natural selection in the origin and maintenance of rapid protein folding by experimentally characterizing the folding kinetics of two de novo designed proteins, NC3-NCAP and ENH-FSM1. These 51 residue proteins, which adopt the helix-turn-helix homeodomain fold, share as few as 12 residues in common with their most closely related natural analog. Despite the replacement of up to 3/4 of their residues by a computer algorithm optimizing only thermodynamic properties, the designed proteins fold as fast or faster than the 35,000 s−1 observed for the closest natural analog. Thus these de novo designed proteins, which were produced in the complete absence of selective pressures or design constraints explicitly aimed at ensuring rapid folding, are among the most rapidly folding proteins reported to date. [Copyright &y& Elsevier]

To what extent does natural selection act to optimize the details of protein folding kinetics? In an effort to address this question, the relationship between an amino acid''s evolutionary conservation and its role in protein folding kinetics has been investigated intensively. Despite this effort, no consensus has been reached regarding the degree to which residues involved in native-like transition state structure (the folding nucleus) are conserved. Here we report the results of an exhaustive, systematic study of sequence conservation among residues known to participate in the experimentally (Φ-value) defined folding nuclei of all of the appropriately characterized proteins reported to date. We observe no significant evidence that these residues exhibit any anomalous sequence conservation. We do observe, however, a significant bias in the existing kinetic data: the mean sequence conservation of the residues that have been the subject of kinetic characterization is greater than the mean sequence conservation of all residues in 13 of 14 proteins studied. This systematic experimental bias gives rise to the previous observation that the median conservation of residues reported to participate in the folding nucleus is greater than the median conservation of all of the residues in a protein. When this bias is corrected (by comparing, for example, the conservation of residues known to participate in the folding nucleus with that of other, kinetically characterized residues) the previously reported preferential conservation is effectively eliminated. In contrast to well-established theoretical expectations, both poorly and highly conserved residues are apparently equally likely to participate in the protein-folding nucleus. [Copyright &y& Elsevier]

A direct conflict between the stabilization free energy parameters of cytochrome c determined by optical methods and by hydrogen exchange (HX) is quantitatively explained when the partially folded intermediates seen by HX are taken into account. The results support the previous HX measurements of intermediate populations, show how intermediates can elude the standard melting analysis, and illustrate how they confuse the analysis when they are significantly populated within the melting transition region. [ABSTRACT FROM PUBLISHER]