Switching Behavior Research Articles

Aggregation-Caused Quenching Dyes as Potent Tools to Track the Integrity of Antitumor Nanocarriers: A Mini-Review

Cancer has become one of the major causes of death worldwide. Chemotherapy remains a cornerstone of cancer treatment. To enhance the tumor-targeting efficiency of chemotherapy agents, pharmaceutical scientists have developed nanocarriers. However, the in vivo structural integrity and dynamic changes in nanocarriers after administration are not well understood, which may significantly impact their tumor-targeting abilities. In this paper, we propose the use of environmentally responsive fluorescent probes to track the integrity of antitumor nanocarriers. We compare three main types of dyes: fluorescence resonance energy transfer (FRET) dyes, aggregation-induced emission (AIE) dyes, and aggregation-caused quenching (ACQ) dyes. Among them, ACQ dyes, possessing sensitive water-quenching properties and easily detected “on–off” switching behavior, are regarded as the most promising choice. We believe that ACQ dyes are suitable for investigating the in vivo fate of antitumor nanocarriers and can aid in designing improved nanoformulations for chemotherapy agents.

Rational vs religious: which is more important for ultra­micro SMEs when dealing with financial institutions?

Purpose This paper aims to examine a range of factors that may influence the intention of ultra-micro-SMEs in Indonesia in choosing the type of microfinance facilities in the case of getting better offerings. Design/methodology/approach Drawing from the theory of planned behavior (TPB) framework, religious elements factors include religious leader endorsements, religiosity and Sharia compliance, whereas socially/commercially driven factors include social and rational sociodemographic indicators. Data was obtained from 319 ultra-micro-SMEs in emerging economies such as Indonesia, and structural equation modeling was used to analyze the survey data. Findings The findings reveal that commercial aspects, as rational variables, have a negative influence on the intention to switch from Islamic to conventional microfinancing. On the contrary, social influence from peers and family positively influences the intention to switch from Islamic to conventional microfinancing. Religious aspects, however, have no influence on the intention to switch or actual switching behavior from Islamic to conventional. Intention to switch was shown to positively influence actual switching behavior as per the prediction of the TPB. Originality/value There is a lack of research on the choice or behavior of ultra-micro-SMEs when deciding whether to use Islamic or conventional microfinance. This study enriches the literature by providing empirical evidence on the factors affecting this choice-making.

Where Does the Proton Go? Structure and Dynamics of Hydrogen-Bond Switching in Aminophosphine Chalcogenides.

Aminophosphates are the focus of research on prebiotic phosphorylation chemistry. Their bifunctional nature also makes them a powerful class of organocatalysts. However, the structural chemistry and dynamics of proton-binding in phosphorylation and organocatalytic mechanisms are still not fully understood. Aminophosphine chalcogenides, preserving the H2N-P+-Ch- structural motif, represent well-suited molecular models that mimic proton-binding, hydrogen-bond switching and supramolecular self-assembling behavior of catalytically and prebiotically relevant molecules. Through spectroscopic (IR, 1H DOSY, 15N NMR), molecular dynamics, and computational investigations, the dynamic proton switching capability of aminophosphate analogs was demonstrated. It was shown under which conditions the amino (NH2) or chalcogen (Ch) functions in H2N-P+-Ch- structural units are protonated. In fact, all conceivable modes of hydrogen-bonding were identified, revealing substantial differences between the oxygen derivative and the heavier congeners. Using coordinating anions, supramolecular zigzag- and cube-shaped arrangements were found in the solid-state and in solution. After break-up of the cube structure, the sulfides and selenides no longer form stable interactions with HCl molecules. In the absence of coordinating anions, protonation of the chalcogen function is preferred. In contrast to the oxygen derivative, the heavier congeners show dynamic intramolecular proton-hopping between the chalcogen and the amino function.

Flexible Synaptic Memristors With Controlled Rigidity in Zirconium-Oxo Clusters for High-Precision Neuromorphic Computing.

Flexible memristors are promising candidates for multifunctional neuromorphic computing applications, overcoming the limitations of conventional computing devices. However, unpredictable switching behavior and poor mechanical stability in conventional memristors present significant challenges to achieving device reliability. Here, a reliable and flexible memristor using zirconium-oxo cluster (Zr6O4OH4(OMc)12) as the resistive switching layer is demonstrated. The optimization of the structural rigidity of the hybrid oxo-cluster network by thermal polymerization allows the precise formation of dispersed conductive cluster networks, enhancing the repeatability of the resistive switching with mechanical flexibility. The optimized memristor exhibits endurance of ∼104 cycles and stable memory retention performance up to 104 s, maintaining a high ION/IOFF ratio of 104 under a bending radius of 2.5mm. Moreover, the device achieves a pattern recognition accuracy of 97.44%, enabled by highly symmetric analog switching with multilevel conductance states. These results highlight that hybrid metal-oxo clusters can provide novel material design principles for flexible and reliable neuromorphic applications, contributing to the development of artificial neural networks.

Introduction to Memristive Mechanisms and Models.

The increase in computational power demand led by the development of Artificial Intelligence is rapidly becoming unsustainable. New paradigms of computation, which potentially differ from digital computation, together with novel hardware architecture and devices, are anticipated to reduce the exorbitant energy demand for data-processing tasks. Memristive systems with resistive switching behavior are under intense research, given their prominent role in the fabrication of memory devices that promise the desired hardware revolution in our intensive data-driven era. They are suggested to provide the hardware substrate to scale up computational capabilities while improving their energy expenditure and speed. This work provides an orientation map for those interested in the vast topic of memristive systems with application to neuromorphic computing. We address the description of the most notable emerging devices and we illustrate models that capture the complex dynamical behavior of these systems under the dynamical-systems framework developed by Chua. We then review the memristive behavior under the perspective of statistical physics and percolation theory suited to describe fluctuations and disorder which are otherwise precluded in the dynamical-system approach. Percolation theory allows the investigation of these systems at the mesoscopic level, enabling material-independent modeling of non-linear conductance networks. We finally discuss recent and less recent successes in deep learning methods that bridge the field of physics-based and biological- inspired neuromorphic computing.

Comparative analysis of eco-epidemic model with disease in prey and gestation delay in predator: implications for population dynamics

Gestation is a very significant phenomenon in predator-prey dynamics. It influences the future predation rates and the growth of species. Gestation is the period of development of an embryo or fetus in a female mammal, from conception to birth. It plays a critical role in population dynamics and reproductive strategies in ecological studies. This article presents a comparative study of eco-epidemic models with and without time delay terms. The model takes into account a prey-predator system, dividing the prey population into susceptible and infected compartments. This article incorporates a time delay into the predator growth term to represent gestation delay. This article investigates the impact of time delay as a gestation delay on the model’s dynamics and compares the results with those of the non-delay model. Our analytical and numerical studies reveal that the time delay stabilizes the model, exhibits switching behaviour, and leads to chaotic behaviour through periodic doubling. Moreover, the gestation delay destabilizes the model by causing Hopf bifurcations to emerge at multiple points. Our findings indicate that the delay model has richer dynamics than the non-delay model. The numerical simulations using MATLAB, along with the DDE-biftool and Matcont packages, illustrate the bifurcation analysis, phase portraits, and time series plots for both models. Our findings highlight the significant effects of gestation delay on the dynamics of eco-epidemic models.

Surfing the Growth Parameters in the Quest for Low-Power, Forming-Free, and Highly Stable TiOx Memristors for Nanoscale Electronics.

Understanding the resistive switching (RS) behavior of oxide-based memory devices at nanoscale is crucial for advancement of high-integration density in-memory computing platforms. This study explores a comprehensive growth parameter space to address the RS behavior of pulsed-laser-deposited substoichiometric TiO2 (TiOx) thin films in search of tailored nanoscale memristors with low-power consumption and high stability. Conductive-atomic-force-microscopy-based measurements facilitate deciphering the switching behavior at nanoscale, providing a direct avenue to understand the microstructure-property relationships. The present investigation reveals that rutile TiOx in an optimal stoichiometric configuration exhibits superior RS attributes, enabling forming-free, low-power, and highly stable memory functionalities at nanoscale. By contrast, the expected formation of the Magnéli phase within a highly defective as-grown TiOx film hinders the occurrence of switching. Detailed analyses yield a comprehensive parametric phase diagram, providing valuable insights to predict the optimal growth parameters for fabricating on-demand TiOx-based switching devices. As bulk RS attributes do not always translate seamlessly to the nanoscale, present study leads the pathway to develop tailored memristors for nanoscale electronics promoting their integration into ultrahigh-density, low-energy-consuming advanced memory technologies across diverse disciplines including robotics, data storage, and sensing.

Tuning resistive switching behavior and conduction mechanism in Se₈₀Te₂₀ alloy with Fe, Co, Ni, and Cu additives

Tuning resistive switching behavior and conduction mechanism in Se₈₀Te₂₀ alloy with Fe, Co, Ni, and Cu additives

Design of spike-timing-dependent plasticity synapses based on CoPt-SOT device and its application in all-spin spiking neural network

Spintronic could be used to simulate synapses or neurons due to its multistate storage characteristics. In this work, a reliable design of all-spin spiking neural networks (SNN) based on spin–orbit torque (SOT) devices has been proposed in A1 CoPt single layer. The CoPt-SOT devices exhibited field-free SOT switching, and the magnetization reversal mechanism was inferred to be a combination of domain nucleation and domain-wall propagation as observed through magneto-optical Kerr microscopy images. Moreover, the current-induced SOT switching process of the device exhibited stable multistate magnetic switching behavior, which can be controlled by varying the amplitude and pulse width of the current pulse. Meanwhile, the spike-timing-dependent plasticity (STDP) curve was inverted when the SOT switching polarity was reversed by different magnetic fields, and the change in anomalous Hall resistances (ΔRH) in the STDP curve was linearly related to the SOT switching ratio. In addition, at the zero magnetic field, we constructed an all-spin SNN using STDP synapses and leaky integrate-and-fire neurons of CoPt-SOT devices. The handwritten digits recognition rate of this all-spin SNN network was 89.9%. These results substantiate that the CoPt single layer represents a promising hardware solution for high-performance neuromorphic computing, with applicability in the domain of SNN.

Thermocontrolled Radical Nucleophilicity vs Radicophilicity in Regiodivergent C-H Functionalization.

The temperature-dependent switching behavior of the saccharin radical is demonstrated, enabling the regiodivergent C3-H and C7-H functionalization of quinoxalin-2(1H)-ones. The saccharin radical was generated through N-Br bond cleavage in N-bromosaccharin (NBSA) and was observed to transition between radical and radicophile roles. At -10 °C, it was utilized as a radicophile, resulting in 100% C3-amination, while at +35 °C, it acted as a radical, leading to exclusive C7-bromination. Radical nucleophilicity was controlled by temperature modulation.

Experimental discrimination of domain switching behaviors within interfacial and bulk layers in the LiNbO3 domain-wall memory

Experimental discrimination of domain switching behaviors within interfacial and bulk layers in the LiNbO3 domain-wall memory

Coordination-Defect-Driven Construction of Responsive Pure-MOF Microspheres for Switchable Mode-Dependent Anticounterfeiting Labels.

Luminescent metal-organic frameworks (MOFs) with exceptional dynamics and diverse active sites possess tremendous potential in information security and anticounterfeiting applications. However, traditional MOF systems are based on broadband spectral signals with spectrum overlap, which easily leads to low-resolution signal identification, compromising the overall security level. Here, we report the coordination-defect-induced amorphous pure-MOF microsphere with switchable whispering-gallery-mode (WGM) signals as a mode-dependent security platform. Amorphous MOF microspheres are prepared by a chlorine coordination-defect-driven growth strategy based on the aperiodic arrangement in coordinate networks. The as-prepared amorphous MOF microspheres with well-defined circular morphology display the typical WGM resonance with dimension-dependent character, permitting the creation of photonic barcodes with substantial encoding capacity. Furthermore, the amorphous MOF microspheres exhibit optical mode switching behavior due to reversible framework shrinkage, which enables the design of covert photonic barcodes as anticounterfeiting labels, finally demonstrating responsive coding property and enhanced information security. The results provide a novel strategy for exploring an MOF-based security platform for information encryption and optical anticounterfeiting.

The push-pull-mooring model of consumer service switching: a meta-analytical review to guide future research

PurposeFor nearly 2 decades, the push-pull-mooring (PPM) model has been used frequently by scholars to explain consumers’ service switching intention and behavior. However, heterogeneity and incomparability between PPM model studies are prevalent issues: The chosen predictor variables, their categorization, their measurement, reported effect sizes, and effect directions vary considerably. By addressing these issues, the present meta-analytical review enables future researchers applying the PPM model to identify relevant variables and use valid measurements.Design/methodology/approachBased on 148 empirical studies employing the PPM model, the variables used to predict consumers’ service switching intention and behavior, their frequency of use, their categorization into push, pull, and mooring factors, and their measurement are assessed. The effect sizes and directions of the relationships between these variables and consumers’ service switching intention and behavior are analyzed using meta-analytic structural equation modeling. Additionally, the predictive capacity of this model and the influence of moderators are assessed.FindingsAmong the 148 empirical studies, 382 different independent variables were used. The three most frequently used and distinctly categorized independent variables are dissatisfaction (push), alternative attractiveness (pull), and switching costs (mooring). Overall, 152 unique sources were cited to measure these variables and the dependent variables. Dissatisfaction and alternative attractiveness increase switching intention, which positively affects switching behavior, while switching costs decrease switching intention. The model explains 30% of the variance in switching intention and 31% of the variance in switching behavior.Originality/valueThis study provides the first meta-analytical review of the PPM model to guide future research systematically.

Re-routing game: The inadequacy of mean-field approach in modeling the herd behavior in path switching

Coordination of vehicle routes is a feasible way to ease traffic congestion issues amid a fixed road infrastructure. Nevertheless, even when optimal route configurations are provided to individual drivers, it is hard to achieve due to the fact that greedy drivers may switch to other routes to lower individual costs. Recent research uses a mean-field cavity approach from spin glass studies to analyze the impact of path switching in optimized transportation networks. However, this method only provides a mean-field approximation, which does not account for the collective herd behavior in path switching due to uncoordinated individual decisions. In this study, we propose an exhaustive cavity approach to investigate the impact of uncoordinated path switching in a re-routing game and reveal that greedy drivers’ decisions can be highly correlated, leading to the failure of mean-field approaches. Our theoretical results fit well with simulations, and our developed framework can be generalized to analyze other games with multiple players and rounds. Our results shed light on the impact of herd behavior among uncoordinated human drivers in suppressing congestion through path coordination.

Memristive behavior of ferrocene-functionalized polymer for artificial nociceptor application

Organic memristors have attracted widespread attention as highly promising candidates for implementing neuromorphic systems and wearable electronic devices. The donor–acceptor (D-A) polymers P1 and P2 are designed and successfully synthesized where the only disparity between the two polymers is the inclusion of a ferrocene (Fc) pendant group. The as-fabricated memristors Ag/P1/ITO and Ag/P2/ITO exhibit volatile threshold switching (TS) behavior, which is dominated by pseudo-bridging conductive filaments (CFs) depending on the diffusion dynamics of the Ag active metal species in the active layer. The more stable TS behavior of the P1-based memristor under a positive voltage sweep is attributed to the Fc units, which can reduce the random growth of CFs to some extent. The volatile ternary switching behavior in the negative working window can be attributed to the synergistic effect of Ag CFs and bilayer ICT process originated from two acceptor units of DPP2T and azobenzene groups. Moreover, the characteristics related to the application of the P1-based memristor on artificial nociceptors are demonstrated, including threshold, relaxation, no adaptation, and sensitization. This work demonstrated that leveraging the effect of constructing bilayer ICT mechanism represents an efficient strategy for building up multi-level memristors capable of versatile applications.

Molecular-scale in-operando reconfigurable electronic hardware.

It is challenging to reconfigure devices at molecular length scales. Here we report molecular junctions based on molecular switches that toggle stably and reliably between multiple operations to reconfigure electronic devices at molecular length scales. Rather than static on/off switches that always revert to the same state, our voltage-driven molecular device dynamically switches between high and low conduction states during six consecutive proton-coupled electron transfer steps. By changing the applied voltage, different states are accessed resulting in in operando reconfigurable electronic functionalities of variable resistor, diode, memory, and NDR (negative differential conductance). The switching behavior is voltage driven but also has time-dependent features making it possible to access different memory states. This multi-functional switch represents molecular scale hardware operable in solid-state devices (in the form of electrode-monolayer-electrode junctions) that are interesting for areas of research where it is important to have access to time-dependent changes such as brain-inspired (or neuromorphic) electronics.

A supramolecular assembly of a novel green fluorescent protein chromophore-based analogue and its application in fluorescence anti-counterfeiting.

Supramolecular fluorescent materials with switchable behavior and induced luminescence enhancement are a new class of special materials for constructing fluorescence anti-counterfeiting materials. Since these materials are constructed by self-assembly through supramolecular host-guest interactions of non-covalent bonds, such fluorescent materials can regulate their optical properties through a reversible assembly-disassembly process. Inspired by the role of the β-barrel scaffold in activating strong fluorescence of a green fluorescent protein (GFP) chromophore, we designed a supramolecular system based on a novel GFP analogue (CA) and cucurbit[7]uril (CB[7]). CA molecules are encapsulated by CB[7] to form a 1 : 2 host-guest assembly, thereby the fluorescence brightness of CA can be tuned. The reversible regulation of fluorescence intensity was additionally realized by controlling the dynamic assembly-disassembly process in the presence of a higher binding competitor, amantadine hydrochloride. The CA-CB[7] system was successfully used for information anti-counterfeiting through the reversible fluorescence readout on A4 paper, which enables the GFP chromophore analogue and cucurbituril system to become a potential candidate for constructing intelligent information encryption and anti-counterfeiting materials.

Analysis of a class of two-delay fractional differential equation.

The differential equations involving two discrete delays are helpful in modeling two different processes in one model. We provide the stability and bifurcation analysis in the fractional order delay differential equation Dαx(t)=ax(t)+bx(t-τ)-bx(t-2τ) in the ab-plane. Various regions of stability include stable, unstable, single stable region (SSR), and stability switch (SS). In the stable region, the system is stable for all the delay values. The region SSR has a critical value of delay that bifurcates the stable and unstable behavior. Switching of stable and unstable behaviors is observed in the SS region.

Mechanistic switch in corrosion behavior of magnesium alloy diamond lattice structures induced by argon plasma treatment

Mechanistic switch in corrosion behavior of magnesium alloy diamond lattice structures induced by argon plasma treatment

Enhancing the Resistive Switching Properties of Nd2Ti2O7 Thin Films through Ca-Doping and Thermal Treatments

This study successfully synthesized Nd2(1-x)Ca2xTi2O7 (x = 0、0.05、0.09、0.13、0.17) thin films via sol-gel method, and systematically investigated the effects of different film thickness, thermal treatment, and doping concentration on the resistive switching characteristics. The results demonstrate that all devices exhibit bipolar resistive switching (BRS) behavior. Compared to undoped NTO thin film devices, doped devices exhibit significant improvements, particularly at a doping concentration of 13%, where the switching cycles increase from 524 to 1022, and the Ron/Roff ratio increases to approximately 102. Furthermore, after post-metal annealing (PMA) treatment, the switching cycles further increase to 1839, with Vset/VReset of −1.48V/0.66V, Ron/Roff >102, and data retention capability reaching 104seconds at both 25°C and 85°C. These improvements in electrical properties are attributed to the effective enhancement of oxygen vacancy concentration within the thin film due to Ca2+ doping, as well as the diffusion effects of Al and In ions after PMA treatment. In summary, this study demonstrates the potential application of Al/Nd2(1-x)Ca2xTi2O7/ITO devices in low-power non-volatile memory applications.