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Purpose: To investigate how well an implant stability quotient (ISQ) represents resonance frequency. Materials and Methods: Benchtop experiments on standardized samples that replicated a mandibular premolar site were conducted to correlate an ISQ value and a resonance frequency to synthetic bone density and an incremental insertion torque; then, a frequency spectrum analysis was performed to check the validity of the resonance frequency analysis (RFA). Brånemark Mk III implants (4 × 11.5 mm; Nobel Biocare) were placed in Sawbones test models of five different densities (40, 30, 40/20, 20, and 15 PCF). An incremental insertion torque was recorded during implant placement. To perform stability measurements, the test models were partially clamped in a vise (unclamped volume: 10 × 20 × 34 mm). A MulTipeg (Integration Diagnostics) was attached to the implants, and a Penguin (Integration Diagnostics) RFA measured ISQ. Simultaneously, the MulTipeg motion was monitored via a laser Doppler vibrometer and processed by a spectrum analyzer to obtain the resonance frequency. Tightness of the clamp was adjusted to vary the resonance frequency. A statistical analysis produced a linear correlation coefficient (R) among the measured ISQ, resonance frequency, and incremental insertion torque. Results: The resonance frequency had high correlation to the incremental insertion torque (R = 0.978), confirming the validity of using RFA for this study. Measured ISQ data were scattered and had low correlation to the resonance frequency (R = 0.214) and the incremental insertion torque (R = 0.386). The spectrum analysis revealed the simultaneous presence of multiple resonance frequencies. Conclusions: For the designed benchtop tests, resonance frequency does indicate implant stability in view of Sawbones density and incremental insertion torque. However, ISQ measurements do not correlate to the resonance frequency and may not reflect the stability when multiple resonance frequencies are present simultaneously. [ABSTRACT FROM AUTHOR]

Premature life exposure, meaning an immature central nervous system, presents a significant challenge for the development of postural control and, in turn, overall motor development. Preventing motor delay thus requires identifying, characterizing, and quantifying deficit in postural control as early as possible. In our study, we reviewed the procedures used in past studies to assess postural control among individuals born preterm, specifically the characterization of participants, the instruments and motor tasks involved, the types of data collected and analyzed, and the outcomes. To that end, we performed a literature search on PubMed, Wiley Online Library, Web of Science, and Scopus using Boolean logic and assessed the quality of the studies with a standardized assessment based on the Strengthening the Reporting of Observational Studies in Epidemiology guidelines and the Cochrane Handbook for Systematic Reviews of Interventions. Of 35 potential studies, 24 were included; all evaluated infants born preterm, but six did not include a control group of full-term infants. Although the heterogeneity of measurements, variability of instruments, and divergence in motor tasks examined limit definitive conclusions based on quantitative synthesis and the generalization of the results, most studies revealed dysfunctional postural control among individuals born preterm. [ABSTRACT FROM AUTHOR]

Multiple sclerosis is a neurodegenerative disease that causes balance deficits, even in early stages. Evidence suggests that people with multiple sclerosis (PwMS) rely more on vision to maintain balance, and challenging balance with optical flow perturbations may be a practical screening for balance deficits. Whether these perturbations affect standing balance in PwMS is unknown. Therefore, the purpose of this study was to examine how optical flow perturbations affect standing balance in PwMS. We hypothesized that perturbations would cause higher variability in PwMS compared with matched controls during standing and that standing balance would be more susceptible to anterior–posterior (A–P) perturbations than medial–lateral (M–L) perturbations. Thirteen PwMS and 13 controls stood under 3 conditions: unperturbed, M–L perturbation, and A–P perturbations. A–P perturbations caused significantly higher A–P trunk sway variability in PwMS than controls, although both groups had similar center-of-pressure variability. Both perturbations increased variability in A–P trunk sway and center of pressure. Trunk variability data supported the hypothesis that PwMS were more susceptible to optical flow perturbations than controls. However, the hypothesis that A–P perturbations would affect balance more than M–L perturbations was partially supported. These results suggest potential for optical flow perturbations to identify balance deficits in PwMS. [ABSTRACT FROM AUTHOR]

This work introduces a simplified deposition procedure for multidimensional (2D/3D) perovskite thin films, integrating a phenethylammonium chloride (PEACl)-treatment into the antisolvent step when forming the 3D perovskite. This simultaneous deposition and passivation strategy reduces the number of synthesis steps while simultaneously stabilizing the halide perovskite film and improving the photovoltaic performance of resulting solar cell devices to 20.8%. Using a combination of multimodal in situ and additional ex situ characterizations, it is demonstrated that the introduction of PEACl during the perovskite film formation slows down the crystal growth process, which leads to a larger average grain size and narrower grain size distribution, thus reducing carrier recombination at grain boundaries and improving the device's performance and stability. The data suggests that during annealing of the wet film, the PEACl diffuses to the surface of the film, forming hydrophobic (quasi-)2D structures that protect the bulk of the perovskite film from humidity-induced degradation.

Metal halide perovskite solar cells (PSCs) are infamous for their batch-to-batch and lab-to-lab irreproducibility in terms of stability and performance. Reproducible fabrication of PSCs is a critical requirement for market viability and practical commercialization. PSC irreproducibility plagues all levels of the community; from institutional research laboratories, start-up companies, to large established corporations. In this work, the critical function of atmospheric humidity to regulate the crystallization and stabilization of formamidinium lead triiodide (FAPbI3) perovskites is unraveled. It is demonstrated that the humidity content during processing induces profound variations in perovskite stoichiometry, thermodynamic stability, and optoelectronic quality. Almost counterintuitively, it is shown that the presence of humidity is perhaps indispensable to reproduce phase-stable and efficient FAPbI3-based PSCs.

Despite being one of the oldest data structures in computer science, hash tables continue to be the focus of a great deal of both theoretical and empirical research. A central reason for this is that many of the fundamental properties that one desires from a hash table are difficult to achieve simultaneously; thus many variants offering different trade-offs have been proposed. This article introduces Iceberg hashing, a hash table that simultaneously offers the strongest known guarantees on a large number of core properties. Iceberg hashing supports constant-time operationswhile improving on the state of the art for space efficiency, cache efficiency, and low failure probability. Iceberg hashing is also the first hash table to support a load factor of up to 1-o(1) while being stable, meaning that the positionwhere an element is stored only ever changes when resizes occur. In fact, in the setting where keys are T(logn) bits, the space guarantees that Iceberg hashing offers, namely that it uses at most log x |U | n x +O(n log logn) bits to store n items froma universeU, matches a lower bound by Demaine et al. that applies to any stable hash table. Iceberg hashing introduces new general-purpose techniques for some of the most basic aspects of hashtable design. Notably, our indirection-free technique for dynamic resizing, which we call waterfall addressing, and our techniques for achieving stability and very-high probability guarantees, can be applied to any hash table that makes use of the front-yard/backyard paradigm for hash table design. [ABSTRACT FROM AUTHOR]

While shifts in gut microbiota have been studied in diseased states, the temporal variability of the microbiome in cats has not been widely studied. This study investigated the temporal variability of the feline dysbiosis index (DI) and the abundance of core bacterial groups in healthy adult cats. The secondary aim was to evaluate the relationship between the fecal abundance of Clostridium hiranonis and the fecal concentrations of unconjugated bile acids. A total of 142 fecal samples collected from 17 healthy cats were prospectively included: nine cats with weekly collection over 3 weeks (at least four time points), five cats with monthly collection over 2 months (three time points), and three cats with additional collections for up to 10 months. The DI remained stable within the reference intervals over two months for all cats (Friedman test, p > 0.2), and 100% of the DI values (n = 142) collected throughout the study period remained within the RI. While some temporal individual variation was observed for individual taxa, the magnitude was minimal compared to cats with chronic enteropathy and antibiotic exposure. Additionally, the abundance of Clostridium hiranonis was significantly correlated with the percentage of fecal primary bile acids, supporting its role as a bile acid converter in cats.

Abstract: Theory predicts intraguild predation (IGP) to be unstable despite its ubiquity in nature, prompting exploration of stabilizing mechanisms of IGP. One of the many ways IGP manifests is through inducible trophic polymorphisms in the intraguild (IG) predator, where a resource-eating predator morph competes with the intraguild (IG) prey for the shared resource while a top predator morph consumes the IG prey. Cannibalism is common in this type of system due to the top predator morph’s specialization on the trophic level below it, which includes the resource-eating predator morph. Here, we explore the consequences of inducible trophic polymorphisms in cannibal predators for IGP stability using an IGP model with and without cannibalism. We employ linear stability analysis and identify regions of coexistence based on the top predator morph’s preference for conspecifics vs. heterospecifics and the IG prey’s competitive ability relative to the resource-eating morph. Our findings reveal that preferential cannibalism (i.e., the preferential consumption of conspecifics) stabilizes the system when the IG prey and resource-eating morph have similar competitive abilities for the shared resource. Though original IGP theory finds that the IG prey must be a superior resource competitor as a general criterion for coexistence, this is not typically the case when the predator has an inducible trophic polymorphism and the resource-eating morph is specialized in resource acquisition. Preferential cannibalism may therefore be a key stabilizing mechanism in IGP systems with a cannibalistic, trophic polymorphic IG predators, providing further insight into what general mechanisms stabilize the pervasive IGP interaction.

Topic models are becoming a frequently employed tool in the empirical methods repertoire of information systems and management scholars. Given textual corpora, such as consumer reviews and online discussion forums, researchers and business practitioners often use topic modeling to either explore data in an unsupervised fashion or generate variables of interest for subsequent econometric analysis. However, one important concern stems from the fact that topic models can be notorious for their instability, i.e., the generated results could be inconsistent and irreproducible at different times, even on the same dataset. Therefore, researchers might arrive at potentially unreliable results regarding the theoretical relationships that they are testing or developing. In this paper, we attempt to highlight this problem and suggest a potential approach to addressing it. First, we empirically define and evaluate the stability problem of topic models using four textual datasets. Next, to alleviate the problem and with the goal of extracting actionable insights from textual data, we propose a new method, Stable LDA, which incorporates topical word clusters into the topic model to steer the model inference toward consistent results. We show that the proposed Stable LDA approach can significantly improve model stability while maintaining or even improving the topic model quality. Further, employing two case studies related to an online knowledge community and online consumer reviews, we demonstrate that the variables generated from Stable LDA can lead to more consistent estimations in econometric analyses. We believe that our work can further enhance management scholars' collective toolkit to analyze ever-growing textual data. [ABSTRACT FROM AUTHOR]

Department stores invest in loyalty strategies that largely focus on retaining current high value customers in response to increasing competition in retail shopping. In this study, we examine the contribution of the top 20% customers for transaction frequency and value ("heavy buyers") to the total sales, and the consistency of this contribution across departments within a store. We also investigate the heavy buyer stability over time across 3 years, from over 550 million transactions from a department store chain in East Asia. The results show that the Pareto ratio of the top 20% spenders account for 71% of revenue (and 52% of the total transactions), and the top 20% transactors represent 58% of revenue (and 62% of total transactions), which may signal the role of such heavy buyers to overall stores sales. At each department level, the heavy buyers (by value) contribute from 65% to 86% of the department revenue. Despite this, the stability of the top 20% segment over time varies greatly by department from 11% to 74%. Finally, whether high value customers in one department store also translate across departments, depends mainly on the department size in terms of its shopper penetration. The research furthers our knowledge on Pareto Law, with important implications for customer retention strategies and loyalty programs especially for retailers. [ABSTRACT FROM AUTHOR]

Objective: To assess the effect of topically applied hyaluronic acid (HA) on the stability of immediately loaded implants in the posterior maxilla. Materials and Methods: For the clinical study, a total of 20 implants were placed in 14 patients seeking the replacement of missing single or multiple posterior maxillary teeth. The patients were randomly divided into two groups. In the clinical control group (CC group), 10 implants were placed and immediately loaded, while in the clinical study group (CS group), 10 implants were coated with HA immediately before placement and immediately loaded. All patients had implant stability clinically evaluated at implant placement time (T0) and 1 (T1), 3 (T3), and 6 (T6) months after loading. Peri-implant pocket depth and modified sulcus bleeding index were evaluated clinically at 6 months in all patients. Bone density was evaluated radiographically after 3 months. All the clinical and radiographic data were subjected to statistical analysis. For the animal study, a total of 12 implants were placed in the tibiae of six rabbits. For each rabbit, 1 implant without any applied HA was placed in the left tibia (AC group), and 1 implant coated with HA was placed in the right tibia (AS group). The rabbits were euthanized at 21 and 45 days after implant insertion. Results: There were no significant statistical differences between the two groups regarding implant stability, peri-implant pocket depth, modified sulcus bleeding index, or bone density from the palatal and apical aspects. However, there was a significant statistical difference in the bone density from the buccal aspect in favor of the study group. The animal study showed that the newly formed bone in the right tibiae showed improved quantity and quality of bone, as it had denser bone trabeculae and smaller marrow spaces compared to the left tibiae. Conclusion: In the clinical study, the application of hyaluronic acid had a superior effect on the buccal bone density around immediately loaded implants. In the animal study, hyaluronic acid had a synergistic effect on the quality and quantity of bone formation around dental implants. [ABSTRACT FROM AUTHOR]

This paper is devoted to observe the physical attributes of static spherically symmetric isotropic compact stellar candidates in the context of Rastall theory of gravity. In order to inspect the structural composition of compact objects, the Heintzmann ansatz is taken into account. The unknown parameters associated with Heintzmann ansatz are evaluated through matching conditions with derived values of radii and masses of some specific star models. The consistency of the adopted ansatz is analyzed via graphical interpretation of matter variables, equation of state parameter, mass components, energy constraints, causality condition, stellar equation and adiabatic index for several choices of Rastall parameter. It is observed that the stars under consideration manifest stable structures corresponding to Heintzmann ansatz in this framework. Moreover, it is shown that for vanishing Rastall coupling parameter, the standard outcomes of general relativity can be retrieved. [ABSTRACT FROM AUTHOR]

The stability of rural credit cooperatives is closely linked to regional economic development in China's vast rural areas. This study aims to investigate how rural credit cooperatives in China can enhance their stability and achieve high-quality development using panel data from 87 county rural credit cooperatives in Shaanxi Province from 2008 to 2016. The Cov-AHP is employed to build an evaluation system and the effect of inclusive finance on the risk-taking capacity of rural credit cooperatives is analysed using a fixed effects model. Results demonstrate that inclusive finance can improve the risk-taking capacity of rural credit cooperatives and enhance their stability. This effect is more significant for rural credit cooperatives with a larger share of corporate shares, although property rights reform and the launch of community banks may weaken this effect. This study recommends vigorously promoting the development of inclusive finance, improving the operational mode of rural commercial banks, strengthening the corporate governance system of rural credit cooperatives, and enhancing the level of financial services for agriculture, rural areas, and farmers. These implications are important for promoting the further reform of rural credit cooperatives, especially in developing countries. [ABSTRACT FROM AUTHOR]

BACKGROUND: Transcranial direct current stimulation (tDCS), as a non-invasive brain stimulation technique, can enhance human muscle strength or improve single-leg landing stability instantly, but no relevant research has demonstrated this yet. OBJECTIVE: To investigate the effect of tDCS on the stability of single-leg landings in human subjects. METHODS: Male undergraduate students from Wuhan Sports University were recruited as study participants. They were divided into two groups, A (n=6) and B (n=5), using a random number table. Group A underwent a sham stimulation session followed by a 3-day washout period, after which they received tDCS. Conversely, Group B received tDCS initially, followed by a 3-day washout period, and subsequently underwent the sham stimulation session. Following the respective stimulation sessions, an immediate single-leg landing test was administered to assess and collect biomechanical parameters. Data resulting from the tDCS intervention were aggregated and analyzed as the experimental group dataset, whereas data stemming from the sham stimulation were consolidated as the control group dataset. RESULTS AND CONCLUSION: Regarding core stability, the tDCS intervention showed a significant interaction with landing height on the maximal trunk flexion angle (P < 0.05). A paired comparison of the data showed a significant decrease in the maximum trunk flexion angle following true stimulation compared to sham stimulation at a 30-cm landing height. Additionally, the tDCS intervention had a significant main effect on the maximum trunk lateral bending angle and the mean trunk lateral bending angular velocity (P < 0.05). Following true stimulation, there was a significant decrease in the maximum trunk lateral bending angle and the mean trunk lateral bending angular velocity compared to sham stimulation. In terms of lower limb joint stability, the tDCS intervention had a significant main effect on the maximum dynamic ankle valgus angle (P < 0.05). This resulted in a significant decrease in the angle following true stimulation compared to sham stimulation. In addition, the tDCS intervention had a significant main effect on the peak muscle activation of the lateral head of the gastrocnemius lateralis (P < 0.05). This showed a significant increase after true stimulation compared to sham stimulation. An interaction between the tDCS intervention and landing height was observed for the peak muscle activation of the tibialis anterior (P < 0.05). Paired comparison analyses revealed a significant increase in muscle activation after true stimulation specifically at a 60-cm landing height. Regarding center of pressure stability, there were no significant interactions or main effects of the tDCS intervention on the mean lateral displacement, mean lateral displacement velocity, mean anterior-posterior displacement, or mean anterior-posterior displacement velocity at the center of pressure (P > 0.05). Furthermore, the tDCS intervention had no significant main effects on any of the center of pressure indicators (P > 0.05). In conclusion, tDCS can immediately improve core stability and lower limb joint stability during single-leg landing, making it an effective warm-up technique for improving single-leg landing stability and reducing the risk of lower limb injuries. [ABSTRACT FROM AUTHOR]

In this article, a fast numerical method is developed for solving the FitzHugh-Nagumo (FHN) model by combining two-grid finite element (TGFE) algorithm in space with a linearized variable-time-step (VTS) two-step backward differentiation formula (BDF2) in time. This algorithm mainly included two steps: firstly, the nonlinear coupled system on the coarse grid is solved by a nonlinear iteration; secondly, a linearized coupled system on the fine grid by making use of a Taylor formula is formulated, and the numerical solution pair is solved directly. The techniques of the discrete orthogonal convolution (DOC) kernels and the discrete complementary convolution (DCC) kernels are used to derive the optimal error estimations in L 2 -norm and the stability analysis for the fully discrete scheme on the coarse and fine grids, and to prove the optimal H 1 -norm error estimation for the fully discrete TGFE scheme. These analyses hold for adjacent time-step ratios 0 < r k ≤ 4.8645 − δ (δ being an arbitrarily small constant). Finally, the effectiveness and computing efficiency of the proposed algorithm are verified through several numerical examples. [ABSTRACT FROM AUTHOR]

The catalytic efficiency of the cathode is paramount in elevating the operational efficacy of low-temperature solid oxide fuel cells (LT-SOFCs) through expeditious facilitation of the oxygen reduction reaction (ORR). Cathode confronts formidable challenges due to oxygen reduction reaction (ORR) kinetics. This work aims to develop a high-performance cathode by doping strontium (Sr) into Nd 2- x Sr 2 x NiO 4. We synthesized a series of Nd 2- x Sr 2x NiO 4 (x : 0, 0.03, 0.06, 0.1) samples with varying Sr doping levels and evaluated their electrochemical performances. Nd2- x Sr 2 x NiO 4 with optimal ratio (x : 0.06) delivers the highest peak power density of 620–338 mw cm−2 at 550-470 °C among all four samples. The electrochemical impedance spectroscopy of the optimal composition revealed that Nd 2- x Sr 2 x NiO 4 exhibits low electrode polarization resistance of 0.34 Ω cm 2 , depicting its high catalytic performance and compatibility with the electrolyte and anode. Furthermore, XPS spectra also suggest higher surface oxygen vacancies than the other three samples, subsequently improving the conductivity and catalytic activity. Along with high power and OCVs, Nd 2- x Sr 2 x NiO 4 cathode-based SOFC is persistently stable for 40 h without significant degradation. These results conclusively point to demonstrating Nd 2- x Sr 2 x NiO 4 as a high-performing cathode for LT-SOFCs. [ABSTRACT FROM AUTHOR]

This work investigates the stability for the wave equation with damping γ (t , x) (− Δ x) α ∂ t u defined on a bounded domain Ω ⊂ R d , d ≥ 1. The damping coefficient γ (t , x) ≥ 0 may degenerate to zero at some (t , x) ∈ [ τ , + ∞) × Ω. In contrast to the classical geometric control condition (GCC), we give the integral control condition (ICC) which means γ only has a positive lower bound in the sense of integral. [ABSTRACT FROM AUTHOR]

The stability of an approximating sequence (A n) for an operator A usually requires, besides invertibility of A , the invertibility of further operators, say B , C , ... , that are well-associated to the sequence (A n). We study this set, { A , B , C , ... } , of so-called stability indicators of (A n) and connect it to the asymptotics of ‖ A n ‖ , ‖ A n − 1 ‖ and κ (A n) = ‖ A n ‖ ‖ A n − 1 ‖ as well as to spectral pollution by showing that lim sup Spec ε A n = Spec ε A ∪ Spec ε B ∪ Spec ε C ∪ .... We further specify, for each of ‖ A n ‖ , ‖ A n − 1 ‖ , κ (A n) and Spec ε A n , under which conditions even convergence applies. [ABSTRACT FROM AUTHOR]

Continuous silicon carbide fibers (SiC f) reinforced SiC ceramic matrix composites (SiC f /SiC CMCs) are promising thermostructural materials with a broad range of high-end technology applications. For the excellent performance of SiC f /SiC CMCs, the interphase plays a crucial role in tailoring the overall mechanical properties and service lifetime of SiC f /SiC CMCs. During the past decades, tremendous effort has been made to develop better interphase materials and deepen the understanding of their functions and mechanisms. In this paper, an overview of the latest advancements in a variety of interfacial coatings, including pyrolytic carbon, boron nitride, newly developed layered candidates, porous oxides and multilayers, is provided. Emphasis is placed on the engineering of constituents, microstructure and interphase thickness, as well as their effects on the mechanical properties and stability of SiC f /SiC CMCs. Moreover, the challenges and future opportunities to achieve the desired behavior of SiC f /SiC CMCs by interphase engineering are discussed. [Display omitted] [ABSTRACT FROM AUTHOR]

In this paper, we propose a new tritrophic food chain model. We address the conditions for the coexistence of two different zooplankton species and one phytoplankton species. The results of the numerical and analytical studies of the model show that the most relevant parameters influencing the plankton ecosystem, to maintain a stable coexistence equilibrium, are the: carrying capacity and the constant intrinsic growth rate of the phytoplankton population, and the conversion rate with a mortality rate of carnivorous zooplankton. We prove the existence and direction of Hopf bifurcation in non delay system. To account for the time delay in the conversion of herbivorous consumption to carnivorous zooplankton, we incorporate a discrete delay into the consume response function. Furthermore, we establish some adequate conditions to prove the occurrence of Hopf bifurcation induced by delay in the delayed model. We also plot two-parameter bifurcation diagrams. The numerical results support the analytical findings. [ABSTRACT FROM AUTHOR]

This work investigates the global dynamics of the bottom hole assembly with non-uniformly distributed cutters on drill-bit which improves stability of steady drilling. In this work, the drill string with a bottom hole assembly is considered as a lumped parameter model in the axial and torsional directions to accommodate axial and torsional vibrations, respectively. The regenerative effect due to the variation in the depth of cut is considered the only source of instability in the system. The engagement of individual cutters with the cut surface is modeled by formulating separate cut surface profile between two simultaneous cutters which is essential in capturing the true global dynamics of the system. Linear stability analysis through eigenvalue analysis reveals the system's improved stability compared to the system equipped with uniformly distributed cutters. An optimal distribution of cutters on the drill-bit for different number of cutters leading to the most stable steady drilling is obtained. This optimal distribution has been found to be robust with respect to changes in the rock strength as well as drill-rig parameters. A detailed nonlinear numerical analysis of the system with the optimal distribution reveals the existence of subcritical and supercritical Hopf bifurcation at different lobes of stability boundaries. Further analysis unveils various complex phenomenon, such as the co-existence of the steady solutions with the chaotic solution, partial bit-bounce, complete bit-bounce, and stick–slip vibrations. [ABSTRACT FROM AUTHOR]

This paper is concerned with the problem of an ellipsoid of revolution rolling on a horizontal plane under the assumption that there is no slipping at the point of contact and no spinning about the vertical. A reduction of the equations of motion to a fixed level set of first integrals is performed. Permanent rotations corresponding to the rolling of an ellipsoid in a circle or in a straight line are found. A linear stability analysis of permanent rotations is carried out. A complete classification of possible trajectories of the reduced system is performed using a bifurcation analysis. A classification of the trajectories of the center of mass of the ellipsoid depending on parameter values and initial conditions is performed. [ABSTRACT FROM AUTHOR]

In recent years, notable progress in computational density functional theory (DFT) has facilitated the collection of extensive datasets in the field of materials science. Machine learning is a crucial technique for effectively processing and analyzing these large datasets and accelerating the creation of new compounds. In this work, we employ the Extreme Gradient Boosting (XGBoost) classification algorithm to predict the crystal structure of 381 halides and oxide perovskites using 78 features. We achieved a classification accuracy of 76.62% for these materials. Subsequently, we utilized the Random Forest and XGBoost algorithms to investigate a dataset comprising 761 perovskite materials from the material project database to predict the band gap energy (best accuracy = 84.78%, mean absolute error(MAE) = 0.410 eV, root mean square error (RMSE) = 0.594 eV) and formation energy (best accuracy = 94.81%, MAE = 0.083 eV/atom, RMSE = 0.157 eV/atom), all of these prediction results based on the chemical formulas. Notably, the feature importance analysis shows the significant influence of the number of d electrons in the d orbit of the B atom on both band gap (Eg) and formation energy (EF) properties. Finally, we applied our prediction model to identify stable perovskite solar cells, achieving an accuracy of 85.18%. These findings provide valuable guidelines for the discovery of stable perovskite solar cells and help researchers tailor the composition of perovskite materials to optimize their light-harvesting capabilities, leading to higher-power conversion efficiencies. [ABSTRACT FROM AUTHOR]

The novelty of this contribution is to propose an implicit numerical scheme for solving time-dependent boundary layer problems. The scheme is multi-step and consists of two stages. It is third-order accurate in time and constructed on three-time levels. For spatial discretization, a fourth-order compact scheme is adopted. The stability of the proposed scheme is analyzed for scalar linear partial differential equation (PDE) that shows its conditional stability. The convergence of the scheme is also provided for a system of time-dependent parabolic equations. Moreover, a mathematical model for heat and mass transfer of mixed convective Williamson nanofluid flow over flat and oscillatory sheets is modified with the characteristic of the Darcy–Forchheimer model. The results show that the temperature profile rises by developing thermophoresis and Brownian motion parameter values. Also, the proposed scheme is compared with an existing Crank–Nicolson method. It is found that the proposed scheme converges faster than the existing one for solving scalar linear PDE as well as the system of linear and nonlinear parabolic equations, which are dimensionless forms of governing equations of a flow phenomenon. The findings provided in this study can serve as a helpful guide for future investigations into fluid flow in closed-off industrial settings. [ABSTRACT FROM AUTHOR]

We consider the viscous incompressible fluids in a three-dimensional horizontally periodic domain bounded below by a fixed smooth boundary and above by a free moving surface. The fluid dynamics are governed by the Navier-Stokes equations with the effect of gravity and surface tension on the free surface. We develop a global well-posedness theory by a nonlinear energy method in low regular Sobolev spaces with several techniques, including: the horizontal energy-dissipation estimates, a new tripled bootstrap argument inspired by Guo and Tice [Arch. Ration. Mech. Anal. (2018)]. Moreover, the solution decays asymptotically to the equilibrium in an exponential rate. • The global well-posedness has been proved in lower regularity space. • The asymptotic stability has been proved around the equilibrium. • The exponential decay of energy has been proved. [ABSTRACT FROM AUTHOR]

Solidifying the soft lattice of all‐inorganic mixed‐halide perovskites is of great importance to restrain the notorious halide segregation under persistent light illumination. Herein, a multifunctional columnar macrocyclic molecule additive, namely cucurbituril into perovskite precursor to enhance the crystallization and reduce the defect density in the final perovskite film is introduced. Based on the theoretical calculation and simulation, the cucurbituril molecule with a strong double‐ended negatively‐charged cavity surrounded by terminated oxygen atoms not only coordinates with dangling Pb2+ ions to form host‐guest complexation but also induces an electric dipole field at perovskite grain boundary to effectively repel the iodide ion migration from the inside grain to the defective boundary, significantly suppressing the halide segregation and improving the device performance. As a result, the carbon‐based, all‐inorganic CsPbI2Br solar cell achieves an enhanced efficiency of 15.59% with great tolerance to environmental stresses. These findings provide new insights into the development of a novel passivation strategy with macrocyclic molecules for making high‐efficiency and stable perovskite solar cells. [ABSTRACT FROM AUTHOR]

Aim Methods Results Conclusions The current study aims to characterize the longitudinal patterns of depression subtypes and investigate the associations among the stability of depression subtypes, COVID‐19‐related stressors, and depression severity.The study utilized data from the Canadian Longitudinal Study on Aging, which is a national, long‐term study of Canadian adults aged 45 and older (n = 12,957). Latent profile analysis was used to identify latent depression subtypes. Latent transition analysis was then applied to assess the stability of these subtypes over time. Hierarchical multivariate linear regression was used to explore the relationships among these identified depression subtypes, COVID‐19‐related stressors, and depression severity among males and females, respectively.Distinct depression subtypes were identified. Except for atypical depression, other depression subtypes showed greater stability over time. We also found that melancholic depression (B = 9.432) and typical depression (B = 6.677) were strongly associated with depression severity during the pandemic. Health‐related stressors (B = 0.840), conflict (B = 3.639), difficulties accessing resources (B = 0.927), separation from family (B = 0.840), and caregiving experience (B = 0.764), were significantly associated with increased depression severity. Sex‐specific analyses also revealed differences in the associations between stressors and depression severity between males and females.This study contributes valuable insights into the latent clustering of depression subtypes and their stability. Stressors were associated with increased depression severity, with distinct associations observed among males and females. These findings have implications for targeted early interventions and integrated clinical management strategies by providing the evidence base for tailored mental health care during and after the pandemic. [ABSTRACT FROM AUTHOR]

A Sr-deficiency approach is utilized to adjust the composition of the standard Sr 2-x Fe 1.5 Mo 0.25 Sc 0.25 O 6 (SFMS) material, with the goal of improving the performance of the SFMS cathode in proton-conducting solid oxide fuel cells (H–SOFCs). The Sr-deficiency concentration is restricted to 10% at the Sr site, and an increase in Sr-deficiency leads to the formation of more oxygen vacancies. However, the presence of increased oxygen vacancies does not consistently enhance the diffusion capabilities of charge carriers. The excess of oxygen vacancies impedes the movement of oxygen and protons. The optimal oxygen and proton transport capabilities are achieved when the Sr-deficiency level is set at 5%. Specifically, this is observed in the compound Sr 1.9 Fe 1.5 Mo 0.25 Sc 0.25 O 6 (S1.9FMS). The enhanced oxygen and proton diffusion kinetics enable H–SOFCs to achieve exceptional performance when employing the S1.9FMS cathode, reaching a power density of 1709 mW cm−2 at 700 °C with a low polarization resistance of 0.023 Ω cm2. The fuel cell's output exceeds that of many previously reported H–SOFCs. Furthermore, the fuel cell utilizing the S1.9FMS cathode not only exhibits excellent fuel cell performance but also maintains reliable operational stability. This indicates that employing the Sr-deficiency technique with an appropriate level of deficiency is a successful approach to enhance the cathode performance for H–SOFCs. • A Sr-deficiency approach was used to tailor Sr 2-x Fe 1.5 Mo 0.25 Sc 0.25 O 6 (SFMS). • The Sr-deficient SFMS showed improved oxygen and proton diffusion kinetics. • A high fuel cell performance was obtained with the Sr 1.9 Fe 1.5 Mo 0.25 Sc 0.25 O 6 cathode. • Good stability was retained for the Sr 1.9 Fe 1.5 Mo 0.25 Sc 0.25 O 6 cathode. [ABSTRACT FROM AUTHOR]

With the growing hydrogen economy, hydrogen is expected to play a significant part in the decarbonization of the world's energy supply. However, the use of hydrogen technologies necessitates the implementation of rigorous safety measures, such as the deployment of accurate hydrogen gas detection systems. Tin oxide (SnO 2) has been mainly studied to detect H 2 gas-sensing applications due to its significant chemical and thermal stability properties. The present review article aims to provide state-of-the-art knowledge of current developments of low-cost, eco-friendly hydrogen (H 2) gas sensors (HGS) based on functionalized tin oxide (SnO 2) nanostructures (SNS), offering greater efficiency and enhanced precision. The review article discuss the various technologies with their fundamental mechanism of hydrogen gas sensing. In this review article, the different fabrication routes of SNS coupled with modifications in their structural, surface, chemical, and electrical properties via metal doping, heterojunctions, ion implantation, light-assisted, carbon, and polymer-based hybrids are taken into account. Further, the study emphasized factors affecting sensing performance, recent technological advancements, and prevailing challenges in the area of SNS-inspired HGS. The review presents a few knowledge gaps, translated herewith as future perspectives and recommendations to instant possibility for future research and development. Hence, the present study could foster novel initiatives that may pave the way to revolutionizing SnO 2 -based HGS. [Display omitted] • The review proves a state-of-the-art of current advances in SnO 2 -based H 2 sensor. • Article includes a comprehensive study of different hydrogen sensing technologies. • Different fabrication routes of SnO 2 -based H 2 sensors are summarized. • SnO 2 modifications via heterojunction, ion & light irradiation, etc. are explained. • Recent technological advancements, and prevailing challenges are well defined. [ABSTRACT FROM AUTHOR]

The peptide CIGB‐210 inhibits HIV replication, inducing a rearrangement of vimentin intermediate filaments. The assessment of the in vitro serum and plasma stability of this peptide is important to develop an optimal pharmacological formulation. A half‐life of 17.68 ± 0.59 min was calculated for CIGB‐210 in human serum by reverse‐phase high‐performance liquid chromatography (HPLC) and mass spectrometry (MS). Eight metabolites of CIGB‐210 were identified with this methodology, all of them lacking the N‐terminal moiety. A previously developed CIGB‐210 in‐house competitive ELISA was used to compare the stability of CIGB‐210 derivatives containing either D‐amino acids, acetylation at the N‐terminus, or both modifications. The half‐life of CIGB‐210 in serum was five times higher when measured by ELISA than by HPLC/MS, and twice higher in plasma as compared to serum. The substitution of D‐asparagine on position 6 doubled the half‐life, while D‐amino acids on positions 8 and 9 did not improve the stability. The acetylation of the N‐terminus resulted in a 24‐fold more stable peptide in plasma. The positive effect of N‐terminal acetylation on CIGB‐210 serum stability was confirmed by the HPLC/MS method, as the half‐life of the peptide was not reached after 2 h of incubation, which represents more than a 6.8‐fold increase in the half‐life with respect to the original peptide. [ABSTRACT FROM AUTHOR]

We propose a notion of stability for constant k$k$‐mean curvature hypersurfaces in a general Riemannian manifold and we give some applications. When the ambient manifold is a Space Form, our notion coincides with the known one, given by means of the variational problem. [ABSTRACT FROM AUTHOR]

In this paper, we study Chaplain–Lolas model in three dimensional bounded domain, which describes the invasion and diffusion process of solid tumors during the vascular growth stage. Although the model has received extensive attention since it was proposed, the existence of solutions in three-dimensional space is still missing, and only a global small solution is established by Pang and Wang (Math Models Methods Appl Sci 28(11):2211–2235, 2018) with sufficiently small proliferation coefficient. As for long time behavior, there are only corresponding stability result of constant steady-state for the case without ECM remodelling (Hillen et al. in Math Models Methods Appl Sci 25(1):165–198, 2013; Tao and Winkler in SIAM J Math Anal 47:4229–4250, 2016). If the remodeling effect of ECM is considered, the relevant research is still blank. In this paper, we first pay our attention to the study of existence of global strong solution and long time behavior. We prove that when the ratio of cell proliferation coefficient to chemotactic intensity μ χ 2 is large, there exists a unique global strong solution around the equilibrium state (1, 1, 0), and the global strong solution converges exponentially to the constant equilibrium point. In fact, such a largeness restriction on μ χ 2 is actually necessary to some extent, since that the constant equilibrium point (1, 1, 0) is actually linearly unstable when such a condition is not satisfied. Subsequently, we turn our attention to the study of dynamic behavior of solutions. We introduce a time periodic external force to this system, and prove that the solution will gradually show the same periodic behavior under the action of periodic external force, and become a time periodic solution. At last, we analysis the stability and instability of equilibrium points, and discuss the influence of spatial diffusion, chemotaxis and haptotaxis effect on the stability of solutions. In particular, we find that only chemotaxis can change the stability of the solution and make the originally stable equilibrium (1, 1, 0) unstable, while the haptotactic term has no effect on the stability. [ABSTRACT FROM AUTHOR]

The characteristics of subvisible particles (SbVPs) are critical quality attributes of injectable and ophthalmic solutions in pharmaceutical manufacturing. However, current compendial SbVP testing methods, namely the light obstruction method and the microscopic particle count method, are destructive and wasteful of target samples. In this study, we present the development of a non-destructive SbVP analyzer aiming to analyze SbVPs directly in drug product (DP) containers while keeping the samples intact. Custom sample housings are developed and incorporated into the analyzer to reduce optical aberrations introduced by the curvature of typical pharmaceutical DP sample containers. The analyzer integrates a light-sheet microscope structure and models the side scattering event from a particle with Mie scattering theory with refractive indices as prior information. Equivalent spherical particle size under assigned refractive index values is estimated, and the particle concentration is determined based on the number of scattering events and the volume sampled by the light sheet. The resulting analyzer's capability and performance to non-destructively analyze SbVPs in DP containers were evaluated using a series of polystyrene bead suspensions in ISO 2R and 6R vials. Our results and analysis show the particle analyzer is capable of directly detecting SbVPs from intact DP containers, sorting SbVPs into commonly used size bins (e.g. ≥ 2 µm, ≥ 5 µm, ≥ 10 µm, and ≥ 25 µm), and reliably quantifying SbVPs in the concentration range of 4.6e2 to 5.0e5 particle/mL with a margin of ± 15 % error based on a 90 % confidence interval. [ABSTRACT FROM AUTHOR]

The incorporation of leucine (Leu), a hydrophobic amino acid, into pharmaceutically relevant particles via spray-drying can improve the physicochemical and particulate properties, stability, and ultimately bioavailability of the final product. More specifically, Leu has been proposed to form a shell on the surface of spray-dried (SD) particles. The aim of this study was to explore the potential of Leu in the SD protein/trehalose (Tre) formulation to control the water uptake and moisture-induced recrystallization of amorphous Tre, using lysozyme (LZM) as a model protein. LZM/Tre (1:1, w/w) was dissolved in water with varied amounts of Leu (0 - 40%, w/w) and processed by spray-drying. The solid form, residual moisture content (RMC), hygroscopicity, and morphology of SD LZM/Tre/Leu powders were evaluated, before and after storage under 22°C/55% RH conditions for 90 and 180 days. The X-ray powder diffraction results showed that Leu was in crystalline form when the amount of Leu in the formulation was at least 20% (w/w). Thermo-gravimetric analysis and scanning electron microscopy results showed that 0%, 5%, and 10% (w/w) Leu formulations led to comparable RMC and raisin-like round particles. In contrast, higher Leu contents resulted in a lower RMC and increased surface corrugation of the SD particles. Dynamic vapor sorption analysis showed that partial recrystallization of amorphous Tre to crystalline Tre·dihydrate occurred in the 0% Leu formulation. However, adding as little as 5% (w/w) Leu inhibited this recrystallization during the water sorption/desorption cycle. In addition, after storage, the formulations with higher Leu contents showed reduced water uptake. Instead of observing recrystallization of amorphous Tre in 0%, 5%, and 10% (w/w) Leu formulations, recrystallization of amorphous Leu was noted in the 5% and 10% (w/w) Leu formulations after storage. In summary, our study demonstrated that the addition of Leu has the potential to reduce water uptake and inhibit moisture-induced recrystallization of amorphous Tre in the SD protein/Tre powder system. [Display omitted] • Leu was in crystalline form when the amount of Leu in the SD LZM/Tre formulation was not less than 20 % (w/w). • The addition of as little as 5 % Leu could inhibit the recrystallization of amorphous Tre during the water sorption/desorption cycle. • Higher Leu contents resulted in a lower RMC and an increased surface corrugation of the SD particles. • Higher Leu contents led to less water uptake after storage. • Rather than recrystallization of amorphous Tre, recrystallization of amorphous Leu was observed in both 5% and 10% Leu formulations after storage. [ABSTRACT FROM AUTHOR]

The extensive and widespread incorporation of wind farms into transmission networks produces many challenges. One of the necessities is to improve power transmission capability to transport large levels of wind energy over long distances. The development of series compensators is a proven method of increasing the power transmission capacity of existing transmission lines and it is of great importance for the grid integration of large wind farms. At the same time, series compensation lines create sub-synchronous resonance (SSR) problems in turbo generators. As a result, electrical unsteadiness may occur in the sub-synchronous frequency components and there is the possibility of failure in the turbo generator tube of the shaft. This paper proposes a novel approach for analyzing SSR in wind farms connected with voltage source inverter (VSI) based photovoltaic cells. The Genetic Window Optimization (GWO) algorithm is used to analyze the multiple electrical parameters that cause SSR. These parameters are the series compensation range, power generation and wind velocity. Steady-state stability is carried out through eigenvalues and participation factors under the various operating conditions of wind farms. The dynamic stability analysis is also achieved through simulations of electromagnetic transients using PSCAD/EMTDC software for the first IEEE bench mark system. Simulation results of wind farms are interfaced with a prototype of real-time photovoltaic cell. A hardware model of solar cells is also presented. The high-level accuracy of GWO results is compared with existing techniques such as Particle Swarm Optimization (PSO) and FIREFLY algorithms. [ABSTRACT FROM AUTHOR]

The primary challenge facing perovskite nanocrystals (PNCs) is their stability, which hinders their potential impact on the industry. This study focuses on new organic–inorganic metal halide perovskites (OIMHPs) with stable deep blue emission using the beneficial encapsulation aspects of metal–organic frameworks (MOFs). Novel (Et)3NHPbBr3 PNCs with deep blue emission were synthesized via the facile ligand‐assisted reprecipitation (LARP) technique. To address both stability issues and low emission efficiency, the (Et)3NHPbBr3 PNCs were effectively embedded within zinc‐based mesoporous MOF‐5 structures. The pore structure of MOF‐5 microporous (with pores size of 1.68 nm) was initially modified to mesoporous (M3 with pores size of 36.88 nm) to facilitate the localization of PNCs inside MOF pores. Then, a full series of experimental parameters were optimized, which resulted in about 10‐fold enhancement in photoluminescence quantum efficiency (PLQE) from 6% for the bare (Et)3NHPbBr3 PNCs to 58% for the (Et)3NHPbBr3@MOF‐5 composite with emission signal located at around 394 nm. The emission stability of the fabricated composite was also investigated against external conditions and showed that the optimized composite has an excellent emission after 180 days of storage in environmental conditions, along with a preserved PL emission at elevated temperatures up to 100 °C. This study presents a straightforward and cost‐effective method for producing novel deep‐blue emissive (Et)3NHPbBr3 PNCs encapsulated within MOFs, showcasing substantial improvements in PLQE and stability that are crucial for the development of efficient optoelectronic devices. [ABSTRACT FROM AUTHOR]

We consider a class of recent rigidity results in a convex cone \Sigma \subseteq \mathbb {R}^N. These include overdetermined Serrin-type problems for a mixed boundary value problem relative to \Sigma, Alexandrov's soap bubble-type results relative to \Sigma, and Heintze-Karcher's inequality relative to \Sigma. Each rigidity result is obtained here by means of a single integral identity and holds true under weak integral overdeterminations in possibly non-smooth cones. Optimal quantitative stability estimates are obtained in terms of an L^2-pseudodistance. In particular, the optimal stability estimate for Heintze-Karcher's inequality is new even in the classical case \Sigma = \mathbb {R}^N. Stability bounds in terms of the Hausdorff distance are also provided. Several new results are established and exploited, including a new Poincaré-type inequality for vector fields whose normal components vanish on a portion of the boundary and an explicit (possibly weighted) trace theory – relative to the cone \Sigma – for harmonic functions satisfying a homogeneous Neumann condition on the portion of the boundary contained in \partial \Sigma. We also introduce new notions of uniform interior and exterior sphere conditions relative to the cone \Sigma \subseteq \mathbb {R}^N, which allow to obtain (via barrier arguments) uniform lower and upper bounds for the gradient in the mixed boundary value-setting. In the particular case \Sigma =\mathbb {R}^N, these conditions return the classical uniform interior and exterior sphere conditions (together with the associated classical gradient bounds of the Dirichlet setting). [ABSTRACT FROM AUTHOR]

Chimeric antigen receptor (CAR) T-cell products are commonly generated using lentiviral vector (LV) transduction. Optimal final formulation buffer (FFB) supporting LV stability during cryostorage is crucial for cost-effective manufacturing. To identify the ideal LV FFB composition for ex vivo CAR-T production, primary human T cells were transduced with vesicular stomatitis virus G-protein (VSV-G) -pseudotyped LVs (encoding a reporter gene or an anti-CD19-CAR). The formulations included phosphate-buffered saline (PBS), HEPES, or X-VIVOTM 15, and stabilizing excipients. The functional and viral particle titers and vector copy number were measured after LV cryopreservation and up to 24 h post-thaw incubation. CAR-Ts were produced with LVs in selected FFBs, and the resulting cells were characterized. Post-cryopreservation, HEPES-based FFBs provided higher LV functional titers than PBS and X-VIVOTM 15, and 10% trehalose-20 mM MgCl 2 improved LV transduction efficiency in PBS and 50 mM HEPES. Thawed vectors remained stable at +4°C, while a ≤ 25% median decrease in the functional titer occurred during 24 h at room temperature. Tested excipients did not enhance LV post-thaw stability. CAR-Ts produced using LVs cryopreserved in 10% trehalose- or sucrose-20 mM MgCl 2 in 50 mM HEPES showed comparable transduction rates, cell yield, viability, phenotype, and in vitro functionality. A buffer consisting of 10% trehalose-20 mM MgCl 2 in 50 mM HEPES provided a feasible FFB to cryopreserve a VSV-G -pseudotyped LV for CAR-T-cell production. The LVs remained relatively stable for at least 24 h post-thaw, even at ambient temperatures. This study provides insights into process development, showing LV formulation data generated using the relevant target cell type for CAR-T-cell manufacturing. [ABSTRACT FROM AUTHOR]

This study presents the interfacial behaviour of benzoylated cellulose of different wettability from melon and moringa pods waste using Pickering emulsions systems. The benzoylated cellulose was prepared in an aqueous alkaline medium using benzoyl chloride as a modifying agent and characterized by X-ray diffraction, thermogravimetric analysis, Fourier transform infrared spectroscopy and scanning electron microscopy (SEM). The X-ray diffraction showed that crystallinity of cellulose from moringa and melon are 67.47 and 70.20%, respectively. The functionalized derivatives are thermally stable than the native counterpart. The SEM revealed that isolated cellulose suffered surface degradation upon functionalization as a result of the repeated collision between reactants. The wetting properties of the cellulose can be controlled by using different quantities of modifying agents, and the emulsions stability depend on the wettability of the emulsifiers. The higher stability recorded for the emulsions stabilized by benzoylated cellulose from moringa pod waste revealed that cellulose wettability depends on the sources. [ABSTRACT FROM AUTHOR]

Summary: In order to improve the adsorption properties and stability of porous starch, the porous starch made from ground rice starch was doubly modified by cross‐linking and esterification using sodium trimetaphosphate (STMP) as a cross‐linking agent and octenyl succinic anhydride (OSA) as an esterifying agent. Structural analysis of the samples showed that the phosphate group in STMP formed a new P‐O‐C covalent bond with the hydroxyl group in starch by substitution, OSA combined with the hydroxyl group of starch formed an ester carbonyl group, and all cross‐linking and esterification occurred in the amorphous region of starch. DSC and TG/DTG analysis showed that STMP modification performed better than OSA modification in thermal stability. However, by analysis of the oil absorption properties and freeze–thaw stability, the OSA‐modified porous starch exhibited better oil‐holding rate and freeze–thaw stability. [ABSTRACT FROM AUTHOR]

This paper aims at studying synchronization, stability and motion characteristics of a new generalized dynamical model with two rigid bodies (RBs), driven by multiple eccentric rotors (ERs) uniformly distributed on the circumference of two different RBs. Using Lagrange's equation, the motion differential equations of the system are deduced. The generalized theoretical analytical expressions of the criteria for implementing synchronization and stable operation of multiple ERs are obtained. Based on the above theoretical results, and taking the present dynamical model with six ERs for example, numerical qualitative discussions are given to deeply reveal the stable states and motion characteristics of the system in different resonant regions. The simulations are further carried out quantitatively, which verifies the validity of the above theoretical and numerical qualitative results. It is shown that, in the sub-resonant state with respect to the natural frequency of the main vibrating system, the stable zero phase difference between arbitrary two ERs on each RB can be achieved, in this case, the relative circular motion of two RBs with anti-phase is realized. This paper can lay a foundation for designing some new types of large scale high-frequency vibrating ball mills with high supply power. [ABSTRACT FROM AUTHOR]

In this work, the miller with a feed-forward capacitor compensated three-stage Operational Transconductance Amplifier (OTA) for a wide range of load capacitors is presented. The proposed OTA can drive a load capacitor with a phase margin of more than ${60^o}$ 60 o from a smaller load capacitor of $1\;pF$ 1 pF to a larger load capacitor of $1\;nF$ 1 nF. It is difficult to stabilise multi-stage OTA for a wide range of load capacitors. The OTA needs a good compensator to stabilise the OTA. The proposed compensator uses a miller capacitor along with the small feed-forward capacitor to stabilise the three-stage OTA for a wide range of load capacitors. Usually, the miller compensated multi-stage OTA with more than two stages is unstable for the smaller load capacitors and demands a minimum load capacitor for the OTA to be stable, but the proposed OTA is stable even for a very small load capacitor of $1\;pF$ 1 pF. The proposed structure uses a slew-rate enhancer (SRE) to enhance the transient performance of the OTA along with the feed-forward transconductors and achieves a settling time of $1.2\;\mu s$ 1.2 μs over the wide range of load capacitors. [ABSTRACT FROM AUTHOR]

Perovskite solar cells (PSCs) have garnered significant interest in recent years due to their high energy conversion efficiency, unique properties, low cost, and simplified fabrication process. However, the reactivity of these devices to external factors such as moisture, water, and UV light presents significant challenges for their commercial viability, potentially compromising their long-term stability and functionality. To overcome these limitations, researchers have focused on two primary strategies: surface passivation and additive engineering. Recent research developments have shown that surface passivation and additive engineering using conducting polymers (CPs), metal-organic framework materials (MOFs), and inorganic additives have significantly improved the operability of perovskite solar cells (PSCs). CPs form resilient interactions with perovskite grains, enhancing film stability through cross-link bonds. MOFs possess a unique network of functional holes that interact with multiple perovskite layers, maintaining morphology and improving interlayer charge transport. Inorganic additives suppress defects at grain boundaries, promoting the formation and growth of perovskite absorbers while providing mechanical protection. These advancements contribute to overcoming the reactivity limitations of PSCs and bring us closer to the commercialization of this technology. The review focuses on the advancements in similar materials, their passivation principles, and the resulting effects on PSC performance. Key aspects covered include the device structure, targeted defects, passivation processes, and synthesis outcomes. By providing a comprehensive overview, the review aims to assist in the selection and synthesis of novel materials. [ABSTRACT FROM AUTHOR]

This article compared two high-order numerical schemes for convection-diffusion delay differential equation via two fractional operators with singular kernels. The objective is to present two effective schemes that give (3 - α) and second order of accuracy in the time direction when α ∈ (0 , 1) using Caputo and Modified Atangana-Baleanu Caputo derivatives, respectively. We also implemented a trigonometric spline technique in the space direction, giving second order of accuracy. Moreover, meticulous analysis shows these numerical schemes to be unconditionally stable and convergent. The efficiency and reliability of these schemes are illustrated by numerical experiments. The tabulated results obtained from test examples have also shown the comparison of these operators. [ABSTRACT FROM AUTHOR]

We explored two types of anticipatory synergy adjustments (ASA) during accurate four-finger total force production task. The first type is a change in the index of force-stabilizing synergy during a steady state when a person is expecting a signal to produce a quick force change, which is seen even when the signal does not come (steady-state ASA). The other type is the drop in in the synergy index prior to a planned force change starting at a known time (transient ASA). The subjects performed a task of steady force production at 10% of maximal voluntary contraction (MVC) followed by a ramp to 20% MVC over 1 s, 3 s, and as a step function (0 s). In another task, in 50% of the trials during the steady-state phase, an unexpected signal could come requiring a quick force pulse to 20% MVC (0-surprise). Inter-trial variance in the finger force space was used to quantify the index of force-stabilizing synergy within the uncontrolled manifold hypothesis. We observed significantly lower synergy index values during the steady state in the 0-ramp trials compared to the 1-ramp and 3-ramp trials. There was also larger transient ASA during the 0-ramp trials. In the 0-surprise condition, the synergy index was significantly higher compared to the 0-ramp condition whereas the transient ASA was significantly larger. The finding of transient ASA scaling is of importance for clinical studies, which commonly involve populations with slower actions, which can by itself be associated with smaller ASAs. The participants varied the sharing pattern of total force across the fingers more in the task with "surprises". This was coupled to more attention to precision of performance, i.e., inter-trial deviations from the target as reflected in smaller variance affecting total force, possibly reflecting higher concentration on the task, which the participants perceived as more challenging compared to a similar task without surprise targets. [ABSTRACT FROM AUTHOR]

Due to their several attractive properties, BDF-type multistep methods are usually the method-of-choice for solving stiff initial value problems (IVPs) of ordinary differential equations (ODEs) and differential-algebraic equations (DAEs). Recently, a class of BDF-type methods based on linear barycentric rational interpolants (LBRIs), referred to as RBDF methods, was introduced for solving ODEs. In the present paper, we are going to introduce a new family of LBRIs-based BDF-type formulas for the numerical solution of ODEs and DAEs with desirable stability properties and smaller error constants than those of the RBDF methods. Numerical experiments of the proposed methods on some well-known IVPs for ODEs and DAEs with index ≤ 3 illustrate the efficiency and capability of the methods in solving such problems. [ABSTRACT FROM AUTHOR]

This paper focuses on the stability and decay rates of solutions to the three dimensional anisotropic magnetohydrodynamic equations with horizontal velocity dissipation and magnetic damping phenomenon. By fully exploiting the structure of the system, the energy methods and the method of bootstrapping argument, we prove the global stability of solutions to this system with initial data small in H 3 (R 3) . Furthermore, we make use of the integral representation approach to obtain the optimal decay rates of these global solutions and their derivatives. This result along with its proof offers an effective approach to the large-time behavior on partially dissipated systems and reveals the stabilizing phenomenon exhibited by electrically conducting fluids. [ABSTRACT FROM AUTHOR]