Memory Effect Research Articles

Interference of ATP-Adenosine Axis by Engineered Biohybrid for Amplifying Immunogenic Cell Death-Mediated Antitumor Immunotherapy.

Immunogenic cell death (ICD) often results in the production and accumulation of adenosine (ADO), a byproduct that negatively impacts the therapeutic effect as well as facilitates tumor development and metastasis. Here, an innovative strategy is elaborately developed to effectively activate ICD while avoiding the generation of immunosuppressive adenosine. Specifically, ZIF-90, an ATP-responsive consumer, is synthesized as the core carrier to encapsulate AB680 (CD73 inhibitor) and then coated with an iron-polyphenol layer to prepare the ICD inducer (AZTF), which is further grafted onto prebiotic bacteria via the esterification reaction to obtain the engineered biohybrid (Bc@AZTF). Particularly, the designed Bc@AZTF can actively enrich in tumor sites and respond to the acidic tumor microenvironment to offload AZTF nanoparticles, which can consume intracellular ATP (iATP) content and simultaneously inhibit the ATP-adenosine axis to reduce the accumulation of adenosine, thereby alleviating adenosine-mediated immunosuppression and strikingly amplifying ICD effect. Importantly, the synergy of anti-PD-1 (αPD-1) with Bc@AZTF not only establishes a collaborative antitumor immune network to potentiate effective tumoricidal immunity but also activates long-lasting immune memory effects to manage tumor recurrence and rechallenge, presenting a new paradigm for ICD treatment combined with adenosine metabolism.

Investigation of solution structures in a nonlinear electric transmission network incorporating dissipative elements through physical phenomena analysis

This paper presents an innovative approach to solving the voltage equation in a multi-coupled nonlinear transmission network with dissipative elements. By employing the G′G2 -expansion method and fractional derivatives, we explore the behavior of current and voltage, considering memory effects. Our investigation delves into the impact of fractional calculus on signal transmission, revealing insights into period, amplitude, and propagation direction. Additionally, we analyze the influence of obliqueness angles and various fractional-order derivatives on voltage waveforms Stability analysis demonstrates the significant role of dissipative elements and modulation parameters on signal stability and network resistance to interference. Furthermore, we examine the effects of free parameters on signal transmission characteristics. Our findings highlight the intricate interplay between fractional order, wave obliqueness, and physical parameters on voltage propagation, addressing gaps in previous research.

Phase-dependent visual and sensorimotor integration of features for grasp computations before and after effector specification.

The simple act of viewing and grasping an object involves complex sensorimotor control mechanisms that have been shown to vary as a function of multiple object and other task features such as object size, shape, weight, and wrist orientation. However, these features have been mostly studied in isolation. In contrast, given the nonlinearity of motor control its computations require multiple features to be incorporated concurrently. Therefore, the present study tested the hypothesis that grasp computations integrate multiple task features superadditively in particular when these features are relevant for the same action phase. We asked male and female human participants to reach-to-grasp objects of different shapes and sizes with different wrist orientations. Also, we delayed movement onset using auditory signals to specify which effector to use. Using electroencephalography (EEG) and representative dissimilarity analysis to map the time course of cortical activity we found that grasp computations formed superadditive integrated representations of grasp features during different planning phases of grasping. Shape-by-size representations and size-by-orientation representations occurred before and after effector specification, respectively, and could not be explained by single-feature models. These observations are consistent with the brain performing different preparatory, phase-specific computations; visual object analysis to identify grasp points at abstract visual levels and downstream sensorimotor preparatory computations for reach-to-grasp trajectories. Our results suggest the brain adheres to the needs of nonlinear motor control for integration. Furthermore, they show that examining the superadditive influence of integrated representations can serve as a novel lens to map the computations underlying sensorimotor control.Significance Statement The nonlinearity of the sensorimotor control of grasping should require computations to incorporate multiple task features such as object shape, size, and orientation concurrently. However, grasp research so far has primarily investigated the influences of task features in isolation. In contrast, integrated representations of task features have been studied in cognitive paradigms showing that multiple visual and action features are joined together in abstract representations based on working memory or priming effects called events files. Using multivariate analysis of EEG, here we observe a new form of integrated representations of task features for grasping that cannot be explained by single-feature models or event files. Our approach offers novel insights into the preparatory processes of sensorimotor grasp control.

Tailoring the stress-free two-way shape memory effect in sol-gel crosslinked poly(ε-caprolactone)-based semicrystalline networks

Abstract Two-way shape memory polymers are stimulus-responsive materials capable of changing their shape between two configurations based on an on/off thermal stimulus. While the traditional effect has been studied under the application of an external mechanical load, it was demonstrated also in the absence of an external load. Such a response only relies on a carefully tailored macromolecular architecture of the polymer combined with a specific thermo-mechanical protocol. In particular, semicrystalline networks, either consisting of a multi-phase copolymer network or a homopolymer based network with broad phase transitions, have been proposed to this aim under ad-hoc thermo-mechanical histories. In this work, the two-way shape memory behaviour is studied on a poly(ε-caprolactone)-based network, crosslinked by means of a sol-gel approach and tailored on the selection of the molecular weight of the precursor polymer. Changing the prepolymer precursor allowed to tune the melting/crystallization regions of the networks, thus the thermal region of the reversible shape memory effect. The application of properly designed thermo-mechanical cycles allowed to study the two-way shape memory effect without the application of an external load under tensile conditions. Given a specific network, the stress-free actuation of the reversible elongation-contraction cycle under tensile conditions was induced across its specific melting/crystallization region. The extent of the effect was found to depend on the crystalline fraction remaining for the given actuation temperature and on the tensile stretched state imposed on the materials during the training step.
The results were compared with the response achieved under the traditional two-way shape memory protocol under stress. The stress-free two-way shape memory effect was also successfully demonstrated and emphasized, under flexural conditions, which suggests the potential of these materials as intrinsically reversible actuators, promising for applications in the biomedical field and/or for soft robotics. 

The synaptic correlates of serial position effects in sequential working memory

Sequential working memory (SWM), referring to the temporary storage and manipulation of information in order, plays a fundamental role in brain cognitive functions. The serial position effect refers to the phenomena that recall accuracy of an item is associated to the order of the item being presented. The neural mechanism underpinning the serial position effect remains unclear. The synaptic mechanism of working memory proposes that information is stored as hidden states in the form of facilitated neuronal synapse connections. Here, we build a continuous attractor neural network with synaptic short-term plasticity (STP) to explore the neural mechanism of the serial position effect. Using a delay recall task, our model reproduces the the experimental finding that as the maintenance period extends, the serial position effect transitions from the primacy to the recency effect. Using both numerical simulation and theoretical analysis, we show that the transition moment is determined by the parameters of STP and the interval between presented stimulus items. Our results highlight the pivotal role of STP in processing the order information in SWM.

The capacitance and shape memory effect of highly stretchable and flexible nanocomposite electrodes based on polyaniline

AbstractThe increasing demand for portable and flexible energy storage devices drives the rapid development of flexible electrodes and electrolytes. Meanwhile, the free‐standing polymer electrodes face great chance and challenge. In this work, the stretchable and flexible polyaniline/carbon nanotube/poly(vinyl alcohol) electrode (PANI/CNT/PVA‐E) was fabricated by in‐situ polymerization of aniline in CNT/PVA‐E substrate, where CNT was used to enhance the conductivity and mechanical properties of the polymer electrodes. Compared with PANI/PVA, the comprehensive performance of PANI/CNT/PVA‐E was improved. In addition, the electrochemical performance and tensile property of the electrodes depended on the CNT content. The nanocomposite electrode with 0.25% of CNT possessed optimal properties with high capacitance of 248.69 mF cm−2, and 75.29% of capacity retention over 4000 charge–discharge cycles at 1 mA cm−2. It also exhibited outstanding tensile strength of 3.88 MPa and elongation up to 462.3%. Interestingly, the electrode possessed good heat driven shape memory effect. The temporary shape could be fixed at 70°C under extra force, and the fixed shape recovered within 10 s when it was reheated to the same temperature. It is concluded that the present work may contribute to the development and fabrication of flexible energy‐storage devices, portable and highly stretchable electric devices.

Shape memory and shape recovery characterization of thermoplastic urethane

ABSTRACT Polyurethane shape memory polymer, as a smart material, has been becoming more and more popular due to its greater multifunctionality in various industrial and biomedical applications. Here, the authors reported the characterisation, and comprehensive methodology and acquired the results of thermoplastic urethane (SMTPU) as a shape memory polymer, with 35°C as the glass transition temperature, by examining its creep. This smart polymer exhibits excellent shape memory behaviour due to its steady, chemically cross-linked network. Such behaviour of shape memory polymer determines its usability in various functional applications. Furthermore, the activation temperature range of SMPTPU is close to body temperature and room temperature as well, so it can be employed in more demanding industrial applications. Thus, it becomes essential to investigate the shape-changing/memory behaviour of commercial SMTPU. A quantitative analysis was done to determine the effects of programming temperature, maximum uniaxial strain, and compressive strain on shape memory characteristics viz. the shape recovery ratios and shape fixity ratios. Along with the excellent shape memory effect, this material also exhibits high creep and elasticity at room temperature, indicating that it may be used for various industrial and biomedical applications.

Fluorinated Titanium Oxide (TiO2-xFx) Nanospindles as Ultrasound-Triggered Pyroptosis Inducers to Boost Sonodynamic Immunotherapy.

Pyroptosis is an inflammatory form of programmed cell death associated with the immune system that can be induced by reactive oxygen species (ROS). As a therapeutic strategy with better penetration depth, sonodynamic therapy (SDT) is expected to induce pyroptosis of cancer cells and boost the immune response. However, it is still a limited problem to precisely adjust the structure of sonosensitizers to exhibit satisfactory sono-catalytic properties. Herein, fluorinated titanium oxide (TiO2-xFx) sonosensitizers were developed to induce pyroptosis under ultrasound (US) to boost antitumor immune responses, enabling highly effective SDT. On the one hand, the introduction of F atoms significantly reduced the adsorption energy of TiO2-xFx for oxygen and water, which is conducive to the occurrence of sono-catalytic reactions. On the other hand, the process of F replacing O increased the oxygen vacancies of the sonosensitizer and shortened the band gap, which enabled powerful ROS generation ability under US stimulation. In this case, large amounts of ROS could effectively kill cancer cells by inducing mitochondrial damage and disrupting oxidative homeostasis, leading to significant cell pyroptosis. Moreover, SDT treatment with TiO2-xFx not only suppressed tumor proliferation but also elicited robust immune memory effects and hindered tumor recurrence. This work highlighted the importance of precisely regulating the structure of sonosensitizers to achieve efficient ROS generation for inducing pyroptosis, which sets the stage for the further development of SDT-immunotherapy.

The influence of emotion on temporal context models

ABSTRACT Temporal context models (TCMs) have been influential in understanding episodic memory and its neural underpinnings. Recently, TCMs have been extended to explain emotional memory effects, one of the most clinically important findings in the field of memory research. This review covers recent advances in hypotheses for the neural representation of spatiotemporal context through the lens of TCMs, including their ability to explain the influence of emotion on episodic and temporal memory. In recent years, simplifying assumptions of “classical” TCMs – with exponential trace decay and the mechanism by which temporal context is recovered – have become increasingly clear. The review also outlines how recent advances could be incorporated into a future TCM, beyond classical assumptions, to integrate emotional modulation.

Manipulating and investigating the room-temperature magnetic memory phenomenon: The impact of rare-earth ion doping on nickel oxide nanoparticles

This study investigates the relationship between point defect density and magnetic properties in nickel oxide (NiO) nanoparticles (NPs). Specifically, we explore the effects of 0.5 % trivalent rare-earth ion (RE3+: Ce3+, Pr3+, Nd3+, Sm3+, and Dy3+) doping on NiO NPs, considering the influence of RE3+ ionic radius on structural modulation and magnetic properties. Our findings reveal important trends: increased microstrain (0.08 %–0.17 %) and decreased crystalline size (36–17 nm) with increasing ionic radius (r = 0.91 to 1.01 Å), along with a preference for growth along the (1 1 1) plane over (2 0 0). Additionally, multivalent point defects increase with the increase of ionic radius. Substituting Ni2+ site with RE3+ ion promotes nearest-neighbor weak ferromagnetic interaction over next-nearest-neighbor strong antiferromagnetic (AF) interaction. This leads to a redshift of two magnons (2 M) frequency by 50 cm−1 and enhanced room temperature (RT) magnetization (0.23–0.43 emu/g) with increasing ionic radius. Ce-doped NiO (r = 1.01 Å) shows the smallest crystalline size (17 nm), maximum 2 M redshift, and enhanced RT magnetization (0.43 emu/g) based on interacting bound magnetic polaron model. Ce-, Pr-, Nd-, and Sm-doped NiO NPs exhibit RT magnetic memory effects, while Dy-doped NiO NPs (r = 0.912 Å) display AF properties. Our analysis provides valuable insights for designing RT magnetic memory materials with tailored properties through suitable RE3+ ion substitutions.

Influence of local defects in the generation of memory effect in Dy2Ti2O7 compound: Fe-doped study

The study of defect-induced effects in functional materials is high-priority research for the miniaturization of smart devices. To elucidate the influence of local defects stemming from intrinsic or extrinsic factors on the enigmatic behavior of cooperative spin dynamics, we investigated the Dy2-xFexTi2O7 compound within a narrow Fe substitution range (x = 0–0.15). Our experimental findings unequivocally demonstrate that the dynamic response of cooperative spins and the emergence of anomalous memory effect are intricately linked to local defects. Depending on the nature and dynamics of these defects, the dynamic response of cooperative spins undergoes alteration. Notably, observed anomalous effect becomes more pronounced in scenarios characterized by slower defect dynamics and when cooperative spins are further from equilibrium. The emergence and sensitivity of thermomagnetic hysteresis (memory effect) to cooperative spin dynamics and external stimuli underscore the richness of Dy2Ti2O7 as a material for captivating physics investigations.

Axialgravisolitons at infinite corner

Abstract Gravitational solitons (gravisolitons) are particular exact solutions of Einstein field equation in vacuum build on a given background solution. Their interpretation is not yet fully clear but they contain many of the physically relevant solutions low N-solitons solutions. 
However, a systematic study and characterization of gravisolitons solution for every N is lacking and their relevance in a theory of quantum gravity is not fully understood. This work aims to investigate and characterize some properties of N-axialsoliton solutions such as their asymptotically behaviour and asymptotic symmetries given minimal assumptions on the background metric. We develop an explicit systematic asymptotically expansion for the N-axialsoliton solution and we compute the leading order of the asymptotic killing vectors. Moreover, in the perspective to better understand the role of gravisolitons in quantum gravity we make a link, and a one of the first explicit test, to the corner symmetry proposal deriving which subalgebra of the universal corner symmetry algebra is generated by the asymptotic Killing vectors of N-axialsoliton solution. In the spirit of the corner proposal, the axialgravisoliton corner symmetry algebra (agcsa) can be useful for the quantization of the non-asymptotically flat sector of gravity while, in the spirit of IR triangle, new soft theorems and memory effects could emerge.

The seasonal model of chili price movement with the effect of long memory and exogenous variables for improving time series model accuracy

The seasonal model of chili price movement with the effect of long memory and exogenous variables for improving time series model accuracy

The seasonal model of chili price movement with the effect of long memory and exogenous variables for improving time series model accuracy

This study aimed to explore big-time series data on agricultural commodities with an autocorrelation model comprising long-term processes, seasonality, and the impact of exogenous variables. Among the agricultural commodities with a large amount of data, chili prices exemplified criteria for long-term memory, seasonality, and the impact of various factors on production as an exogenous variable. These factors included the month preceding the new year and the week before the Eid al-Fitr celebration in Indonesia. To address the factors affecting price fluctuations, the Seasonal Autoregressive Fractionally Integrated Moving Average (SARFIMA) model was used to manage seasonality and long-term memory effects in the big data analysis. It improved with the addition of exogenous variables called SARFIMAX (SARFIMA with exogenous variables is known as SARFIMAX). After comparing the accuracy of both models, it was discovered that the SARFIMAX performed better, indicating the influence of seasonality and previous chili prices for an extended period in conjunction with exogenous variables. The SARFIMAX model gives an improvement in model accuracy by adding the effect of exogenous variables. Consequently, this observation concerning price dynamics established the cornerstone for maintaining the sustainability of chili supply even with the big data case.

Fractional dynamics of entropy generation in unsteady mixed convection of a reacting nanofluid over a slippery permeable plate in Darcy–Forchheimer porous medium

AbstractThis paper presents a theoretical investigation of the inherent irreversibility in unsteady fractional time derivative mixed convection of a reacting nanofluid with heat and mass transfer mechanism over a slippery permeable plate embedded in a Darcy–Forchheimer porous medium. The model fractional partial differential equations are obtained based on conservation laws and numerically solved using the implicit finite difference scheme. The study displays and discusses the effects of various emerging parameters on the overall flow structure, such as velocity profiles, temperature distribution, nanoparticles concentration profiles, skin friction, Nusselt number, Sherwood number, entropy generation rate, and Bejan number. It was found that an increase in dimensionless time and fractional parameters leads to a decrease in both the entropy generation rate and the Bejan number. The study revealed that fractional order derivatives can capture intrinsic memory effects, non‐local behaviour, and anomalous diffusion in the nanofluid flow process. This can ultimately lead to better engineering system design and control.

Event-related potentials during encoding coincide with subsequent forced-choice mnemonic discrimination

Computational models and eye-tracking research suggest that encoding variability accounts for the reduced recognition of targets (A) when paired with non-corresponding lures (B′) relative to corresponding lures (A′). The current study examined whether neural activity during learning coincided with subsequent performance on the forced-choice Mnemonic Similarity Task (MST). Event-related potential responses were collected during encoding while young adults completed A–B′ and A–A′ trials of the forced-choice MST. Consistent with previous research, performance was lower on A–B′ trials than A–A′ trials. The subsequent memory effect was not significant for the A–A′ test format. However, for A–B′ trials, we observed a significant Accuracy × Stimulus interaction 1000–1200 ms poststimulus onset across frontal and fronto-central electrodes. As hypothesized, subsequently correct A–B′ trials were associated with a larger amplitude response at encoding to the target (A) than the original version of the non-corresponding lure (B). However, subsequently incorrect trials were associated with a larger amplitude response to the non-corresponding lure (B) than the target stimulus (A). These findings provide additional support for the effect of encoding variability on mnemonic discrimination.

Photo-assisted charging of heterostructured NiCo2S4@NiCo-LDH composite electrode with remarkable photoelectronic memory effect for high-performance asymmetric supercapacitor

Rational establishment of photo-assisted supercapacitor represents a viable strategy for achieving solar energy conversion and storage. In this study, NiCo2S4@NiCo-LDH (NCS@NC-LDH) composite electrode was effectively synthesized for a highly efficient asymmetric supercapacitor (ASC). Specific capacitance of NCS@NC-LDH under light condition (3286.25 F g−1 at 1 A g−1) demonstrated notable improvement in contrast to that under dark condition (2171.5 F g−1 at 1 A g−1). Meanwhile, NCS@NC-LDH displayed strong photoelectronic memory, as a merely 3 % specific capacitance decreased when discharged under dark compared to that of continuous illumination. Additionally, the assembled aqueous ASC (NCS@NC-LDH//AC) exhibited substantial energy density (83.2 Wh kg−1 at 800 W kg−1) under light condition. Density functional theory (DFT) calculation further demonstrated that the formed matched band facilitated efficient generation-transfer of photoinduced electrons/holes and thus improved the energy storage behavior. We anticipated that this work may offer new perspectives on developing multi-component composite electrodes tailored for high-performance solar-driven electrochemical energy storage.

Role of prey refuge and fear level in fractional prey–predator model with anti-predator

Ecological modeling is an effective tool for studying the interactions between predator and prey species by considering various functional responses and ecological effects. Employing computational or mathematical models allows us to determine the impact of specific human interventions or animal behaviors on the evolution of these species. The fear experienced by prey due to the presence of predators plays a crucial role in shaping the dynamics of their interactions. The manuscript focuses on developing and examining a novel prey–predator model that considers predation fear, prey refuge, and anti-predator effects. Caputo fractional derivative is utilized in the construction and analysis of the model, which integrates ecological principles like memory effects to improve our comprehension of species relationship. The study investigates aspects such as stability, well-posedness, and solution uniqueness for the proposed model. We carried out extensive numerical simulation to support theoretical results. Graphical results are provided for the model encompassing a broad spectrum of fractional order values. The effect of the fear level, growth rate of prey, saturation rate and prey refuse on the behavior of the solution are discussed.

Fracton Infrared Triangle

In theories with conserved dipole moment, isolated charged particles (fractons) are immobile, but dipoles can move. We couple these dipoles to the fracton gauge theory and analyze the universal infrared structure. This uncovers an observable double kick memory effect which we relate to a novel dipole soft theorem. Together with their asymptotic symmetries this constitutes the first realization of an infrared triangle beyond Lorentz symmetry. This demonstrates the robustness of these IR structures and paves the way for their investigation in condensed matter systems and beyond. Published by the American Physical Society 2024

Event-related potentials during encoding coincide with subsequent forced-choice mnemonic discrimination

Computational models and eye-tracking research suggest that encoding variability accounts for the reduced recognition of targets (A) when paired with non-corresponding lures (B′) relative to corresponding lures (A′). The current study examined whether neural activity during learning coincided with subsequent performance on the forced-choice Mnemonic Similarity Task (MST). Event-related potential responses were collected during encoding while young adults completed A–B′ and A–A′ trials of the forced-choice MST. Consistent with previous research, performance was lower on A–B′ trials than A–A′ trials. The subsequent memory effect was not significant for the A–A′ test format. However, for A–B′ trials, we observed a significant Accuracy × Stimulus interaction 1000–1200 ms poststimulus onset across frontal and fronto-central electrodes. As hypothesized, subsequently correct A–B′ trials were associated with a larger amplitude response at encoding to the target (A) than the original version of the non-corresponding lure (B). However, subsequently incorrect trials were associated with a larger amplitude response to the non-corresponding lure (B) than the target stimulus (A). These findings provide additional support for the effect of encoding variability on mnemonic discrimination.