Giant Room-Temperature Electrocaloric Effect of Polymer-Ceramic Composites with Orientated BaSrTiO3 Nanofibers.

Cooling based on the electrocaloric effect (ECE) is a promising solution to environmental and energy efficiency problems of vapor-compression refrigeration. Ferroelectric polymer-ceramics nanocomposites, integrating high electric breakdown of organic ferroelectrics and large EC strength of ceramics, are attractive EC materials. Here, we tuned the orientation of Ba0.67Sr0.33TiO3 nanofibers (BST nfs) in the P(VDF-TrFE-CFE) polymer. When the nfs were aligned parallel to the field, a ΔT of 11.3 K with an EC strength of 0.16 K·m/MV was achieved in the blends. The EC strength not only surpasses advanced nanocomposites but also is comparable to ferroelectric ceramics. The simulation indicates that a significantly higher electric field is concentrated in polymer regions around the ends of the orientated nfs, contributing to easier flipping of polymer chains for large ECE. This work provides a new method to obtain large ECE in composites for next-generation refrigeration.

A unified framework of mixed quantum-classical dynamics with trajectory branching.

As popular mixed quantum-classical dynamics methods, trajectory surface hopping and Ehrenfest mean field have been widely utilized to simulate nonadiabatic dynamics. Recently, we have proposed the branching-corrected surface hopping and the branching-corrected mean field methods, both of which closely reproduce the exact quantum dynamics in a series of standard scattering models. Here, the mixed surface hopping and mean field with branching correction (BCSHMF) is presented as a unified framework of mixed quantum-classical dynamics. As benchmarked in thousands of diverse three-level and four-level scattering models, BCSHMF achieves high reliability and flexibility, implying that surface hopping and mean field are compatible with each other in nature, and trajectory branching is essential for the mixed quantum-classical description of nonadiabatic dynamics.

Photoexcitation-controlled self-recoverable molecular aggregation for flicker phosphorescence.

Chemical systems with external control capability and self-recoverability are promising since they can avoid additional chemical or energy imposition during the working process. However, it remains challenging to employ such a nonequilibrium method for the engineering of optoelectronic function and for visualization. Here, we report a functional molecule that can undergo intense conformational regulation upon photoexcitation. It enables a dynamical change in hydrophobicity and a follow-up molecular aggregation in aqueous media, accordingly leading to an aggregation-induced phosphorescence (AIP) behavior. This successive performance is self-recoverable, allowing a rapid (second-scale cycle) and long-standing (>103 cycles) flicker ability under rhythmical control of the AIP. Compared with traditional bidirectional manipulations, such monodirectional photocontrol with spontaneous reset profoundly enhances the operability while mostly avoiding possible side reactions and fatigue accumulation. Furthermore, this material can serve as a type of luminescent probe for dynamically strengthening visualization in bioimaging.

Branching and phase corrected surface hopping: A benchmark of nonadiabatic dynamics in multilevel systems.

Since the seminal work of Tully [J. Chem. Phys. 93, 1061 (1990)], two-level scattering models have been extensively adopted as the standard benchmark systems to assess the performance of different trajectory surface hopping methods for nonadiabatic dynamics simulations. Here, we extend the branching and phase corrections to multilevel systems and combine them with both the traditional fewest switches surface hopping (FSSH) and its variant global flux surface hopping (GFSH) algorithms. To get a comprehensive evaluation of the proposed methods, we construct a series of more challenging and diverse three-level and four-level scattering models and use exact quantum solutions as references. Encouragingly, both FSSH and GFSH with the branching and phase corrections produce excellent and nearly identical results in all investigated systems, indicating that the new surface hopping methods are robust to describe multilevel problems and the reliability is insensitive to the definition of self-consistent hopping probabilities in the adiabatic representation. Furthermore, the branching correction is found to be especially important when dealing with strongly repulsive potential energy surfaces, which are common in realistic systems, thus promising for general applications.

Learning Decoherence Time Formulas for Surface Hopping from Quantum Dynamics.

Surface hopping simulations have achieved great success in many different fields, but their reliability has long been limited by the overcoherence problem. We here present a general machine learning assisted approach to identify optimal decoherence time formulas for surface hopping using exact quantum dynamics as references. In order to avoid computationally expensive force calculations, we use the nuclear kinetic energy and the adiabatic energy difference to iteratively generate the descriptor space. Through multilayer screening of the candidate descriptors and discrete optimization of the relevant parameters, we obtain new energy-based decoherence time formulas. As benchmarked in thousands of diverse multilevel systems and six standard scattering models, surface hopping with our new decoherence time formulas nearly reproduces the exact quantum dynamics while maintaining high efficiency. Thereby, our approach provides a promising avenue for systematically improving the accuracy of surface hopping simulations in complex systems from quantum dynamics data.

Study on the Mechanism of Improving HIV/AIDS Immune Function with Jian Aikang Concentrated Pill Based on Network Pharmacology Combined with Experimental Validation.

Purpose: This study was the first to screen the active compounds of Jian Aikang Concentrated Pill (JAKCP) with network pharmacology, predict its potential targets, screen the signaling pathways, and combine with cellular experimental validation to explore the potential mechanism of JAKCP for the treatment of acquired immunodeficiency syndrome (AIDS). Methods: The main compounds and targets of Chinese herbs in JAKCP were identified by TCMSP; the targets of AIDS were collected from Genecards, Online Mendelian Inheritance in Man (OMIM), Disgenet, Therapeutic Target Database (TTD) and Drugbank; the network of "Chinese herbs-active compounds-targets" for JAKCP was constructed by Cytoscape, and protein-protein interaction (PPI) network was constructed using STRING to generate the intersection targets, Metascape was conducted to analyze the Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG), and the network of "main active compounds-core targets-pathways" was constructed by Cytoscape. Finally, the effect of JAKCP on the survival rate of HIV pseudovirus-infected MT-4 cells was investigated by CCK-8 assay, and the predicted targets were verified by ELISA, qPCR and Western blot. Results: A total of 147 active compounds of JAKCP were screened covering 351 targets and 416 AIDS disease targets were obtained, besides 140 intersection targets and 321 KEGG pathways were collected. Ultimately, quercetin, kaempferol, stigmasterol, beta-sitosterol, epigallocatechin gallate were identified as the important compounds, the core targets are HSP90AA1, IL-10, IL-6, TNF, IL-1ß, TP53, and IL-1ɑ, and the biological pathways and processes mainly include T cell activation, regulation of DNA-binding transcription factor activity and apoptotic signaling pathway. Experiments on the targets of "T cell activation" demonstrated that JAKCP promotes the survival of HIV pseudovirus-infected MT-4 cells. Also, JAKCP down-regulated mRNA and protein levels of IL-1ɑ, IL-1ß, and IL-6 while up-regulated mRNA and protein levels of IL-2, IL-6ST, and IL-10 in vitro. Conclusion: JAKCP exerted regulatory immune functions through multi-component, multi-target and multi-pathway, thereby providing novel ideas and clues for the treatment of AIDS.

Oxytocin is implicated in social memory deficits induced by early sensory deprivation in mice.

Early-life sensory input plays a crucial role in brain development. Although deprivation of orofacial sensory input at perinatal stages disrupts the establishment of the barrel cortex and relevant callosal connections, its long-term effect on adult behavior remains elusive. In this study, we investigated the behavioral phenotypes in adult mice with unilateral transection of the infraorbital nerve (ION) at postnatal day 3 (P3). Although ION-transected mice had normal locomotor activity, motor coordination, olfaction, anxiety-like behaviors, novel object memory, preference for social novelty and sociability, they presented deficits in social memory and spatial memory compared with control mice. In addition, the social memory deficit was associated with reduced oxytocin (OXT) levels in the hypothalamus and could be partially restored by intranasal administration of OXT. Thus, early sensory deprivation does result in behavioral alterations in mice, some of which may be associated with the disruption of oxytocin signaling.