Kinetic Phase Research Articles

Abstract 15277: High-Throughput Optical Oxygen Measurements for Human IPSC-Cardiomyocytes and Ventricular Fibroblasts in 96-Well Plates

For metabolically active cells like cardiomyocytes, a balanced state of oxygen supply and demand is crucial for basic cell function. Human-induced pluripotent stem cell-derived cardiomyocytes (hiPSC-CMs) are a valuable experimental model due of their scalability and relevance to human physiology. Oxygen consumption and availability have not been characterized in high-throughput format (HT), used in pre-clinical studies. Here, we quantified pericellular oxygen in syncytia of hiPSC-CM and human cardiac fibroblasts, grown in glass-bottom 96-well plates ( Fig 1A-C ). We deployed Ruthenium-based oxygen sensors and a ratiometric optical oxygen measurement system ( Fig 1B ) to track pericellular oxygen over time across all wells. Measured ratios were calibrated to % oxygen using two-point calibration with 5% Na 2 SO 3 and upon saturation with ambient air. Solution height and cell density were varied (4 solution heights, 3 cell densities) to understand their role in oxygen diffusion and oxygen consumption rate (OCR) by the cells. Michaelis-Menten kinetics and the Thiele modulus were used to computationally simulate oxygen availability in matching conditions. Without active perfusion or mass transport, for all tested conditions in the hiPSC-CMs, oxygen was depleted to <5% within approximately an hour. The drop of oxygen occurred in two phases - a zero-order decrease phase, followed by Michaelis-Menten kinetic phase ( Fig 1D ). Increase in culture medium volume/ height was found to be a powerful determinate of oxygen availability in simulations and in experiments ( Fig 1E n = 5 per group). Higher cell density correlated with steeper slope in the first phase of decline in oxygen availability, n = 4 per group. Cardiac fibroblasts followed a similar pattern (n = 4 per group) with noticeably slower OCR. Overall, our results indicate that pericellular oxygen in HT glass-bottom plates may reach hypoxic levels quickly; solutions for active mass transport need to be considered.

Plastic collapse analysis in multiaxially loaded defective pipe specimens at different temperatures

A comprehensive numerical investigation is carried out using a newly developed constitutive model to describe failure at low temperatures in multiaxially loaded cracked pipes made of 316L stainless steel. The kinetic phase transformation and the temperature-dependent fracture criterion are implemented to accurately capture the mechanical response at different temperature levels. Although experimental observations of these simulations were not available, their results were quite consistent with some already published results obtained on similar materials and loading conditions at room temperature. The results indicate that the existing multiaxial plastic collapse failure criterion, including shearing, still provides a fail-safe design margin for low temperature loading conditions, including internal pressure. Moreover, martensite kinetic phase transformation plays an important role, especially during straining at low temperatures.

Value of MRI in Differentiation between Benign and Malignant Breast Mass

Objectives: This study aimed to evaluate the role of MRI in differentiation between benign and malignant well-circumscribed breast masses.
 Methods: A prospective cross-sectional study conducted on selected female patients with Breast mass who their age older than 35 years. All patients underwent examination using 1.5 Tesla magnetic resonance unit (MAGNETOM AERA, SIMENS).
 Results: 30 female patients were selected (mean age of 44.2±9.2 years, range between 35-69). Final findings of MRI revealed that 6 (20%) women had malignant breast mass while 24 (80%) women had benign breast mass. The histopathology revealed that 4 (13.3%) women were having malignancy while 26 (86.6%) were having benign breast tumor. There was a highly significant association between malignancy and hyperdense mammography findings of women (p<0.001), multiple lymph nodes for women (p<0.001), increased size of mass by MRI (p<0.001), circumscribed macrolabular lesion on MRI, rapid early kinetic phase of enhanced MRI (p<0.001), washout late kinetic phase enhanced MRI (p<0.001), and MRI kinetic curve type 3(p<0.001). There was a highly significant association between homogenous enhanced MRI findings of women and benign lesions (p<0.001).
 Conclusion: The validity results of MRI in differentiation between benign and malignant circumscribed breast masses are high, except for positive predictive value, and application of kinetic curve dynamic contrast enhancement increases magnetic resonance in differentiation between benign and malignant circumscribed breast masses.

Anomalous transport tuned through stochastic resetting in the rugged energy landscape of a chaotic system with roughness.

Stochastic resetting causes kinetic phase transitions, whereas its underlying physical mechanism remains to be elucidated. We here investigate the anomalous transport of a particle moving in a chaotic system with a stochastic resetting and a rough potential and focus on how the stochastic resetting, roughness, and nonequilibrium noise affect the transports of the particle. We uncover the physical mechanism for stochastic resetting resulting in the anomalous transport in a nonlinear chaotic system: The particle is reset to a new basin of attraction which may be different from the initial basin of attraction from the view of dynamics. From the view of the energy landscape, the particle is reset to a new energy state of the energy landscape which may be different from the initial energy state. This resetting can lead to a kinetic phase transition between no transport and a finite net transport or between negative mobility and positive mobility. The roughness and noise also lead to the transition. Based on the mechanism, the transport of the particle can be tuned by these parameters. For example, the combination of the stochastic resetting, roughness, and noise can enhance the transport and tune negative mobility, the enhanced stability of the system, and the resonant-like activity. We analyze these results through variances (e.g., mean-squared velocity, etc.) and correlation functions (i.e., velocity autocorrelation function, position-velocity correlation function, etc.). Our results can be extensively applied in the biology, physics, and chemistry, even social system.

An online movement and tremor identification algorithm for evaluation during deep brain stimulation

Abstract INTRODUCTION: Deep brain stimulation (DBS) is widely used to alleviate symptoms of movement disorders. During intraoperative stimulation the influence of active or passive movements on the neuronal activity is often evaluated but the evaluation remains mostly subjective. The objective of this paper is to investigate the potential of a previously developed Weighted-frequency Fourier Linear combiner and Kalman filter-based recursive algorithm to identify tremor phases and types. METHODS: Ten accelerometer recordings from eight patients were acquired during DBS from which 186 phases were manually annotated into: rest, postural and kinetic phase without tremor, and rest, postural and kinetic phase with tremor. The method first estimates the instantaneous tremor frequency and then decomposes the motion signal into voluntary and tremorous parts. The tremorous part is used to quantify tremor and the voluntary part to differentiate rest, postural and kinetic phases. RESULTS: Instantaneous tremor frequency and amplitude are successfully tracked online. The overall accuracy for tremorous phases only is 89.1% and 76.3% when also non-tremorous phases are considered. Two main misclassification cases are identified and further discussed. CONCLUSION: The results demonstrate the potential of the developed algorithm as an online tremorous movement classifier. It would benefit from a more advanced tremor detector but nevertheless the obtained digital biomarkers offer an evidence-based analysis and could optimize the efficacy of DBS treatment.

R2 gravity effects on the kinetic axion phase space

In this work we consider the effect of an R 2 term on the kinetic misalignment axion theory. By using the slow-roll assumptions during inflation and the field equations, we construct an autonomous dynamical system for the kinetic axion, including the effects of the R 2 term and we solve numerically the dynamical system. As we demonstrate, the pure kinetic axion attractor is transposed to the right in the field phase space, and it is no longer , but it is , with some non-zero value of the scalar field with . This feature indicates that the kinetic axion mechanism is enhanced, and the axion oscillations are further delayed, compared with the pure kinetic axion case. The phenomenological implications on the duration of the inflationary era, on the commencing of the reheating era and the reheating temperature, are also discussed.

Kinetic Phase Diagram for Nucleation and Growth of Competing Crystal Polymorphs in Charged Colloids.

We determine the kinetic phase diagram for nucleation and growth of crystal phases in a suspension of charged colloids. Exploiting the seeding approach in extensive simulations, we calculate nucleation barrier heights for face-centered cubic (fcc) and body-centered cubic (bcc) phases for varying screening lengths and supersaturations. We determine for the entire metastable fluid region the crystal polymorph with the lowest nucleation barrier, and find a regime close to the triple point where metastable bcc can form due to a lower nucleation barrier, even though fcc is the stable phase. For higher supersaturation, we find that the difference in barrier heights decreases and we observe a mix of hexagonal close-packed, fcc, and bcc structures in the growth of crystalline seeds as well as in spontaneously formed crystals. Our kinetic phase diagram rationalizes the different crystallization mechanisms observed in previous work.

Rapid solidification of hypoeutectic aluminum copper alloys using fast-scanning calorimetry

The rapid solidification behaviour of binary aluminum copper alloys in the hypoeutectic range of compositions has been studied in this work. Solidification at cooling rates up to 40,000 °Cs−1 can be achieved using a chip-based calorimeter, but present challenges in sample preparation and temperature correction, which are addressed in this work. Data from calorimetry has been used to produce fraction of solid curves which are important input to metal manufacturing processing models. Undercoolings range from around 50 °C at 100 °Cs−1 to around 100 °C at 40,000 °Cs−1. From these, a kinetic phase diagram was constructed for the hypoeutectic region of the Al-Cu system, for cooling rates up to 40,000 °Cs−1. The undercoolings measured in this experiment are considerably higher than those predicted theoretically for growth-based rapid solidification, but not as high as those predicted under homogeneous nucleation.

Operando monitoring of single-particle kinetic state-of-charge heterogeneities and cracking in high-rate Li-ion anodes

To rationalize and improve the performance of newly developed high-rate battery electrode materials, it is crucial to understand the ion intercalation and degradation mechanisms occurring during realistic battery operation. Here we apply a laboratory-based operando optical scattering microscopy method to study micrometre-sized rod-like particles of the anode material Nb14W3O44 during high-rate cycling. We directly visualize elongation of the particles, which, by comparison with ensemble X-ray diffraction, allows us to determine changes in the state of charge of individual particles. A continuous change in scattering intensity with state of charge enables the observation of non-equilibrium kinetic phase separations within individual particles. Phase field modelling (informed by pulsed-field-gradient nuclear magnetic resonance and electrochemical experiments) supports the kinetic origin of this separation, which arises from the state-of-charge dependence of the Li-ion diffusion coefficient. The non-equilibrium phase separations lead to particle cracking at high rates of delithiation, particularly in longer particles, with some of the resulting fragments becoming electrically disconnected on subsequent cycling. These results demonstrate the power of optical scattering microscopy to track rapid non-equilibrium processes that would be inaccessible with established characterization techniques.

Using Proton Geminate Recombination as a Probe of Proton Migration on Biological Membranes.

Proton migration on biological membranes plays a major role in cellular respiration and photosynthesis, but it is not yet fully understood. Here we show that proton dissociation kinetics and related geminate recombination can be used as a probe of such proton migration mechanisms. We develop a simple model for the process and apply it to analyze the results obtained using a photo-induced proton release probe (chemically modified photoacid) tethered to phosphatidylcholine membranes. In our theoretical model, we apply approximate treatment for the diffusional cloud of the geminate proton around the dissociated photoacid and consider arbitrary dimension of the system, 1 < d < 3. We observe that in d > 2, there is a kinetic phase transition between an exponential and a power-law kinetic phases. The existence of an exponential decay phase at the beginning of the proton dissociation is a signature of d > 2 systems. In most other cases, the exponential decay phase is not present, and the kinetics follows a diffusional power-law P(t) ∼ t-d/2 that develops after a short initiation time. Specifically, in a 1D case, which corresponds to the desorption of a proton from the surface, the dissociation occurs by the slow power-law and explains the abnormally slow desorption rate reported recently in experiments.

Structural Evolution of Atomically Thin 1T’‐MoTe2 Alloyed in Chalcogen Atmosphere

Alloying is widely applied to tailor properties of 2D materials. Herein, a space‐confined chemical vapor deposition (CVD) strategy to homogeneously grow 100 μm‐sized monolayer 1T’‐MoTe2 in batches is developed. Aberration‐corrected annular dark‐field scanning transmission electron microscopy combined with density functional theory calculations is applied to investigate the atomic structural alteration of 1T’‐MoTe2 alloyed with sulfur. 1T’‐to‐2H phase transition is observed, triggered by both thermodynamic (stability improvement) and kinetic (phase transition barrier reduction) reasons. The alloying degrees of MoS2xTe2(1−x) grown at different temperatures display homophilic and random configurations, respectively, providing a feasible approach to tailor the atomic mixture of the alloying elements. The intralayer reconstruction and the interlayer displacement take place as defect concentration increases at elevated alloying temperatures. In contrast, 1T’‐MoTe2 displays high susceptibility in the presence of oxygen. An encapsulation method is developed using CVD‐grown monolayer MoS2, extending the lifetime of monolayer tellurides from several minutes to at least 24 h. These results gain fundamental insights into the structural change in both the beneficial (sulfurization) and detrimental (oxidation) alloying processes of atomically thin 1T’‐MoTe2 and provide a new degree of freedom for the controllable growth of 2D alloys (i.e., tailoring the alloying degree).

API solubility in semi-crystalline polymer: Kinetic and thermodynamic phase behavior of PVA-based solid dispersions

The formulation of amorphous solid dispersions (ASDs) represents a promising strategy for improving the poor bioavailability of many active pharmaceutical ingredients (APIs). The objective of this study was to investigate and compare the long-term physical stability (LTPS) of polyvinyl alcohol (PVA)-based solid dispersions formulated via hot-melt extrusion (HME) with their respective API–PVA temperature–composition (T–C) phase diagram. Furthermore, the impact of API glass-forming ability (GFA) on the LTPS was evaluated through the selection of two APIs with contrasting GFA (i.e., indomethacin (IND; good GFA) and naproxen (NAP; poor GFA)). Even though the predicted solubility of both APIs in PVA was less than 1 wt% at T = 25 °C, IND remained fully amorphous in HME-formulated IND–PVA extrudates with initial API loadings of 50, 40, and 30 wt% after a 24-month storage period. Meanwhile, NAP recrystallized to a considerable degree in each analogous sample with an amorphous NAP content of 22.5–23.5 wt% remaining after a 12-month storage period. While the constructed T–C phase diagrams were still in agreement with their respective LTPS study, they did not account for the impact of water uptake as well as potential HME-induced effects on the extrudate glass-transition temperature. This work may serve as a useful reference point for researchers who are interested in determining the solubility of an API in a semi-crystalline polymer and the challenges therein.

A Stochastic Reduced-Order Model for Statistical Microstructure Descriptors Evolution

Abstract Integrated computational materials engineering (ICME) models have been a crucial building block for modern materials development, relieving heavy reliance on experiments and significantly accelerating the materials design process. However, ICME models are also computationally expensive, particularly with respect to time integration for dynamics, which hinders the ability to study statistical ensembles and thermodynamic properties of large systems for long time scales. To alleviate the computational bottleneck, we propose to model the evolution of statistical microstructure descriptors as a continuous-time stochastic process using a non-linear Langevin equation, where the probability density function (PDF) of the statistical microstructure descriptors, which are also the quantities of interests (QoIs), is modeled by the Fokker–Planck equation. We discuss how to calibrate the drift and diffusion terms of the Fokker–Planck equation from the theoretical and computational perspectives. The calibrated Fokker–Planck equation can be used as a stochastic reduced-order model to simulate the microstructure evolution of statistical microstructure descriptors PDF. Considering statistical microstructure descriptors in the microstructure evolution as QoIs, we demonstrate our proposed methodology in three integrated computational materials engineering (ICME) models: kinetic Monte Carlo, phase field, and molecular dynamics simulations.

Predicting kinetic interface condition for austenite to ferrite transformation by multi-component continuous growth model

A critical issue restricting the application of Hillert-Agren-Liu solute-drag based model to predict interfacial conditions at a migrating ferrite-austenite interface is the lack of value for trans-interface diffusion parameter, i.e., the L parameter. Even an estimation of the parameter's order of magnitude is difficult due to its ambiguous physical interpretation. In this paper we extend a different solute-drag based model, namely the binary continuous growth model originally developed for rapid solidification, toward austenite to ferrite phase transformation to avoid this long-standing issue. The extensions consist of the treatments of multi-alloying components including interstitial carbon element and Gibbs-Thomson effect. The extended multi-component continuous growth model employs a physical parameter with clear physical meanings, i.e., interface diffusive speed in describing trans-interface energy dissipation, and can predict kinetic interface conditions and spontaneous diffusion-controlled to diffusion-less transition without using the ambiguous L parameter. The model is verified by the good agreement of its calculation results with those predicted by Hillert-Agren-Liu model for Fe–C alloys and Fe–C–Mn alloys. Further the model's advantages over Hillert-Agren-Liu model are demonstrated by calculating the kinetic interface condition phase diagrams of Fe–C–Mn–Ni alloys. It is concluded that the extended multi-component continuous growth model is valuable in unifying the efforts in addressing the common question of predicting deviations from local equilibrium at a fast-migrating interface during solidification and solid-state phase transformation.

Anomalous aggregation regimes of temperature-dependent Smoluchowski equations

Temperature-dependent Smoluchowski equationsdescribe the ballistic agglomeration. In contrast to the standard Smoluchowski equationsfor the evolution of cluster densities, with constant rate coefficients, the temperature-dependent equationsdescribe both-the evolution of the densities as well as cluster temperatures, which determine the agglomeration rates. To solve these equations, we develop a Monte Carlo technique based on the low-rank approximation for the aggregation kernel. Using this highly effective approach, we perform a comprehensive study of the kinetic phase diagram of the system and reveal a few surprising regimes, including permanent temperature growth and "density separation" regime, with a large gap in the size distribution for middle-size clusters. We perform scaling analysis and classify the aggregation kernels for the temperature-dependent equations. Furthermore, we conjecture the lack of gelation in such systems. The results of the scaling theory agree well with the simulation data.

Experimental study on carbon dioxide hydrate formation in the presence of static magnetic field

The formation kinetic parameters, phase equilibrium and dissociation enthalpy of carbon dioxide hydrate in the presence of static magnetic field were investigated in this work. The experiments were carried out in pure water and (0.029, 0.056 and 0.110, mass fraction) sodium chloride (NaCl) aqueous solution with a magnetic field of 0.39 T. The experimental results showed that the induction time of carbon dioxide hydrate nucleation was shortened, the consumption amount and rate of carbon dioxide were significantly increased with the magnetic field. This phenomenon is mainly attributed to the fact that the magnetic effect decreases the contact angle between water and solid surface to reduce the critical size and critical free energy of hydrate nucleation. Moreover, the phase equilibrium of carbon dioxide hydrate in both pure water and NaCl aqueous solution shifted to lower pressure or higher temperature with the magnetic field, and the equilibrium temperature in pure water decreased by 3.0 K, which is due to the change of the hydrogen bond in small clusters and ions mobility by magnetic effect. In addition, the dissociation enthalpies of carbon dioxide hydrate in pure water and (0.029, 0.056 and 0.110) NaCl solution calculated by Clausius-Clapeyron equation were 91.5, 91.4, 62.8 and 52.0 kJ·mol−1, respectively, in the magnetic field, which is related to the movements of ions caused by magnetic effect and heat absorption.

Review of modification strategies in emerging inorganic solid-state electrolytes for lithium, sodium, and potassium batteries

<h2>Summary</h2> The design of solid-state electrolyte (SSE) entails controlling not only its bulk structure but also the internal (e.g., grain boundary and pore) and heterophase (e.g., anode-SSE reaction layer) interfaces. Moreover, defects are integral for establishing both the initial all-solid-state battery (ASSB) cell performance and its ultimate cycling lifetime. This topical review discusses 5 highly promising inorganic lithium-, sodium-, and potassium-based SSEs, providing case studies of strategies to enhance ionic conductivity, tune the internal and heterophase interfaces, and prevent dendrites and deleterious side reactions. The primary focus is on garnet LLZO (Li₇La₃Zr₂O₁₂), argyrodite (Li₆AS₅X, A = P, Sb and X = Cl, Br, I), Na₃AB₄ (A = P, Sb, As and B = S, Se), and NASICON-type electrolytes, with several exploratory potassium systems being presented as well. The article begins with a discussion of the superionic conduction mechanisms, which is assisted by defects, topology, correlation, and disorder. The discussion then shifts to the thermodynamic or kinetic phase stability of metastable SSEs, followed by the SSE internal interfaces (pores and grain boundaries), and finally the complex microstructure associated with the reactive boundaries between the SSE and the metal anode and the SSE and the high-voltage ceramic cathode. This review explores why SSE systems with highly promising bulk ionic conductivity values do not demonstrate comparable performance in full cells. A major cause is the cycling-induced formation of ionically insulating but electrically conducting new phases at both the anode and the cathode. For the SSEs that do not rapidly decompose when contacting the anode, site-specific variations in ionic conductivity/electrical resistivity lead to growth of metal dendrites. In each electrolyte class, creative fabrication strategies have been employed to minimize, but not fully eliminate, new phase formation and dendrites, creating ample opportunities for additional analytical and synthesis-focused research. The emphasis of the discussion is on the bulk doping strategies for SSEs, emerging simulation and characterization findings in relation to SSE performance and cell failure, and new synthesis approaches and cell architectures to improve cycling stability. Throughout the article, outstanding scientific questions are identified, and future research directions are proposed.

Negative rectification and anomalous diffusion in nonlinear substrate potentials: Dynamical relaxation and information entropy.

We numerically investigate the rectification of the probability flux and dynamical relaxation of particles moving in a system with and without noise. The system, driven by two external forces, consists of two substrate potentials that have identical shapes and different potential barriers with different friction coefficients. The deterministic model exhibits the perfect rectification of the probability flux, ratchet effect, and the dependence of the unpredictability of the dynamics on basin of attraction. In contrast, the stochastic model displays that the rectification is sensitive to the temperature and an external bias. They can induce kinetic phase transitions between no transport and a finite net transport. These transitions lead to an unexpected phenomenon, called negative rectification. The results are analyzed through the corresponding time-dependent diffusion coefficient, information entropy (IE), etc. At a low temperature, anomalous diffusions occur in system. For the occurrence of the flux in certain parameter regimes, the larger the diffusion is, the smaller the corresponding IE is, and vice versa. We also present the selected parameter regimes for the emergence of the rectification and negative rectification. Additionally, we study the rectification of the interacting particles in the system and find that the flux may depend on the coupling strength and the number of the interacting particles, and that collective motions occur for the forward flux. Our work provides not only a way of the rectification for the transport of various particles (e.g., ions, electrons, photons, phonons, molecules, DNA chains, nanoswimmers, dust particles, etc.) in physics, chemistry, biology, and material science, but also a design of various circuits.

The kinetic origin of the fluid helicity—A symmetry in the kinetic phase space

Helicity, a topological degree that measures the winding and linking of vortex lines, is preserved by ideal (barotropic) fluid dynamics. In the context of the Hamiltonian description, the helicity is a Casimir invariant characterizing a foliation of the associated Poisson manifold. Casimir invariants are special invariants that depend on the Poisson bracket, not on the particular choice of the Hamiltonian. The total mass (or particle number) is another Casimir invariant, whose invariance guarantees the mass (particle) conservation (independent of any specific choice of the Hamiltonian). In a kinetic description (e.g., that of the Vlasov equation), the helicity is no longer an invariant (although the total mass remains a Casimir of the Vlasov’s Poisson algebra). The implication is that some “kinetic effect” can violate the constancy of the helicity. To elucidate how the helicity constraint emerges or submerges, we examine the fluid reduction of the Vlasov system; the fluid (macroscopic) system is a “sub-algebra” of the kinetic (microscopic) Vlasov system. In the Vlasov system, the helicity can be conserved if a special helicity symmetry condition holds. To put it another way, breaking helicity symmetry induces a change in the helicity. We delineate the geometrical meaning of helicity symmetry and show that for a special class of flows (the so-called epi-two-dimensional flows), the helicity symmetry is written as ∂γ = 0 for a coordinate γ of the configuration space.

Corrosion Behavior and Mechanical Properties of 30CrMnSiA High-Strength Steel under an Indoor Accelerated Harsh Marine Atmospheric Environment.

In this work, the corrosion behavior and mechanical properties of 30CrMnSiA high-strength steel under a harsh marine atmosphere environment were systematically studied using accelerated test technology, along with corrosion kinetic analysis, microstructure and phase composition analysis, electrochemical measurements, and mechanical property tests. The influence of corrosion time on corrosion kinetics was characterized by the weight loss method. The corrosion layer and its product evolution were analyzed by SEM, EDS, XRD, and XPS. The corrosion behavior of steel was studied by a potentiodynamic polarization curve and EIS. Finally, the influence of corrosion on mechanical properties was studied by tensile and fatigue tests. The results show that 30CrMnSiA high strength steel has good corrosion resistance in a harsh marine atmosphere environment. Its corrosion behavior is cyclical: the outer rust layer exfoliated, the inner rust layer became the outer rust layer, and the matrix became inner rust due to the attack by the corrosive medium. The rust layer had a great protective effect on the matrix. The mechanical properties of 30CrMnSiA high-strength steel were reduced under the corrosive environment, and corrosion had a significant effect on its fatigue resistance.