RESUMEN
Conductive bridge random access memory (CBRAM) devices exhibit great potential as the next-generation nonvolatile memory devices. However, they suffer from two major disadvantages, namely relatively high power consumption and large cycle-to-cycle and device-to-device variations, which hinder their more extensive commercialization. To learn how to enhance their device performance, kinetic Monte Carlo (KMC) simulations were employed to illustrate the variation of electroforming processes in nanomanipulated CBRAM devices by introducing an ion-blocking layer with scalable nanopores and tuning the microstructures of dielectric layers. Both the size of nanopores and the inhomogeneity of dielectric layers have significant impacts on the forming processes of conductive filaments. The dielectric layer with a high-content loose texture plus the scalable nanopore-containing ion-blocking layer leads to the formation of size-controlled and uniform filaments, which remarkably contributes to miniaturizable and stable CBRAM devices. Our study provides insights into nanomanipulation strategies to realize high-performance CBRAM devices, still awaiting future experimental confirmation.
RESUMEN
In order to realize the prevailing artificial intelligence technology, memristor-implemented in-memory or neuromorphic computing is highly expected to break the bottleneck of von Neumann computers. Although high-performance memristors have been vigorously developed in labs or in industry, systematic computational investigations on memristors are seldom. Hence, it is urgent to provide theoretical or computational support for the exploration of memristor operating mechanisms or the screening of memristor materials. Here, a computational method based on the main input parameters learned from the first-principles calculations was developed to measure resistance switching of two-terminal memristors with sandwiched metal/ferroelectric semiconductor/metal architectures, which strikingly agrees with the experimental measurements. Based on our developed method, the diverse multiterminal memristors were designed to fully exploit the application of interlocked ferroelectricity of a ferroelectric semiconductor and realize their heterosynaptic plasticity, and their heterosynaptic behaviors can still be well described. Our developed method can provide a paradigm for the emulation of ferroelectric memristors and inspire subsequent computational exploration. Furthermore, our study also supplies a device optimization strategy based on the interlocked ferroelectricity and easy processing of two-dimensional van der Waals ferroelectric semiconductors, and our proposed heterosynaptic memristors still await further experimental exploration.
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BACKGROUND: Colorectal cancer stem cells (CCSCs) are heterogeneous cells that can self-renew and undergo multidirectional differentiation in colorectal cancer (CRC) patients. CCSCs are generally accepted to be important sources of CRC and are responsible for the progression, metastasis, and therapeutic resistance of CRC. Therefore, targeting this specific subpopulation has been recognized as a promising strategy for overcoming CRC. AIM: To investigate the effect of VX-509 on CCSCs and elucidate the underlying mechanism. METHODS: CCSCs were enriched from CRC cell lines by in conditioned serum-free medium. Western blot, Aldefluor, transwell and tumorigenesis assays were performed to verify the phenotypic characteristics of the CCSCs. The anticancer efficacy of VX-509 was assessed in HCT116 CCSCs and HT29 CCSCs by performing cell viability analysis, colony formation, sphere formation, flow cytometry, and western blotting assessments in vitro and tumor growth, immunohistochemistry and immunofluorescence assessments in vivo. RESULTS: Compared with parental cells, sphere cells derived from HCT116 and HT29 cells presented increased expression of stem cell transcription factors and stem cell markers and were more potent at promoting migration and tumorigenesis, demonstrating that the CRC sphere cells displayed CSC features. VX-509 inhibited the tumor malignant biological behavior of CRC-stem-like cells, as indicated by their proliferation, migration and clonality in vitro, and suppressed the tumor of CCSC-derived xenograft tumors in vivo. Besides, VX-509 suppressed the CSC characteristics of CRC-stem-like cells and inhibited the progression of epithelial-mesenchymal transition (EMT) signaling in vitro. Nodal was identified as the regulatory factor of VX-509 on CRC stem-like cells through analyses of differentially expressed genes and CSC-related database information. VX-509 markedly downregulated the expression of Nodal and its downstream phosphorylated Smad2/3 to inhibit EMT progression. Moreover, VX-509 reversed the dedifferentiation of CCSCs and inhibited the progression of EMT induced by Nodal overexpression. CONCLUSION: VX-509 prevents the EMT process in CCSCs by inhibiting the transcription and protein expression of Nodal, and inhibits the dedifferentiated self-renewal of CCSCs.
RESUMEN
Birth defects have always been one of the most important diseases in medical research as they affect the quality of the birth population. Orofacial clefts (OFCs) are common birth defects that place a huge burden on families and society. Early screening and prevention of OFCs can promote better natal and prenatal care and help to solve the problem of birth defects. OFCs are the result of genetic and environmental interactions; many genes are involved, but the current research has not clarified the specific pathogenesis. The mouse animal model is commonly used for research into OFCs; common methods of constructing OFC mouse models include transgenic, chemical induction, gene knockout, gene knock-in and conditional gene knockout models. Several main signal pathways are involved in the pathogenesis of OFCs, including the Sonic hedgehog (SHH) and transforming growth factor (TGF)-ß pathways. The genes and proteins in each molecular pathway form a complex network to jointly regulate the formation and development of the lip and palate. When one or more genes, proteins or interactions is abnormal, OFCs will form. This paper summarises the mouse models of OFCs formed by different modelling methods, as well as the key pathogenic genes from the SHH and TGF-ß pathways, to help to clarify the pathogenesis of OFCs and develop targets for early screening and prevention.