Technologies

The transition to renewable energy is generating numerous changes across different continents, some with greater impact than others, but the progress achieved is recognized and widely accepted. In particular, there are various solutions that include electric vehicles as elements that influence grid behavior when connected. Higher levels of electric vehicle penetration can present opportunities and solutions related to energy storage, V2G connections encompassing the distribution system, and long-term evaluation. High participation in V2G connections maintains the availability of the electrical system, while the high proportion of variable renewable energy sources forms the backbone of the overall electrical system. This study presents a systematic review of V2G systems in the Americas. The design of the Sustainable Mobility scenario and the high participation of V2G maintain the balance of the electrical system for most of the day, simplifying storage equipment requirements. Consequently, the influence of V2G systems on energy storage is an important outcome that must be considered in the energy transition and presents development opportunities for the various countries that make up the Americas. The stored electricity will not only serve as storage for future grid use, but V2G batteries will also act as a buffer between generation from diversified renewable sources and the end-use stage. This article shows that research on the design of V2G energy systems in scientific publications is relatively recent, but it has gained increasing attention in recent years. In total, 151 articles published since 1995 have been identified and analyzed. The overall result indicates that North American countries have developed the most V2G applications, and their deployment in the coming years will be significant. Meanwhile, in South and Central America, these systems are not yet being fully utilized due to the lack of growth in the electric vehicle market.

The stock market serves as an important channel for investors to preserve and increase their assets and has attracted significant attention. However, stock price is affected by multiple factors and represents complex characteristics such as high volatility, nonlinearity, and non-stationarity, making accurate prediction highly challenging. To improve forecasting accuracy, this study proposes FT-iTransformer, a stock price prediction model based on time–frequency domain collaborative analysis. The model integrates a frequency domain feature extraction module and a multi-scale temporal convolution network module to comprehensively capture both time and frequency domain features, and then the extracted features are fused and input into iTransformer. It models the complex relationships among multiple variables through the self-attention mechanism, utilizes the feedforward network to capture temporal dependencies, and finally the prediction results are output through the projection layer. This study conducts both comparative and ablation experiments on six stock datasets to evaluate the proposed FT-iTransformer model. The results of comparative experiments show that, compared with seven mainstream baseline models, such as LSTM, Informer, and FEDformer, FT-iTransformer achieves superior performance on all evaluation metrics. Furthermore, the results of ablation experiments exhibit the contributions of each core module to the overall predictive performance, and confirming the validity of the model’s design. In summary, FT-iTransformer provides an effective framework for predicting stock price accurately.

Cell morphology and its mechanical properties are crucial factors in cancer development, affecting migration, invasiveness, and the potential risk of metastasis. However, most studies address these aspects separately, limiting the understanding of how morphological complexity relates to cellular mechanics. This work presents an integrated approach that simultaneously quantifies morphology and viscoelasticity in the human osteosarcoma cell line MG-63. Stress–relaxation experiments and optical imaging of the same cells were performed using a custom-built system that couples Atomic Force Microscopy (AFM) with an inverted optical microscope. Morphometric parameters were extracted from cell contours, while viscoelastic properties were obtained by fitting AFM data to the Fractional Kelvin (FK) and Fractional Zener (FZ) models. Among the morphological descriptors, the Shape Complexity (SC) was proposed. It is derived from the Lobe Contribution Elliptical Fourier Analysis (LOCO-EFA), which captures fine-scale contour features overlooked by conventional metrics. Experimental results show that, in MG-63 cells, higher SC values are associated with greater stiffness, indicating a correlation between cell shape complexity and cell stiffness. Furthermore, loading-rate analysis shows that the FZ model captures strain-rate-dependent stiffening more effectively than the FK model. This methodology provides a first approach to jointly analyzing quantitative morphological parameters and mechanical properties, underlining the importance of combined studies to achieve a comprehensive understanding of cell behavior.