Spermidine as a target for cancer therapy.

Spermidine, as a natural component from polyamine members, is originally isolated from semen and also existed in many natural plants, and can be responsible for cell growth and development in eukaryotes. The supplementation of spermidine can extend health and lifespan across species. Although the elevated levels of polyamines and the regulation of rate-limiting enzymes for polyamine metabolism have been identified as the biomarkers in many cancers, recent epidemiological data support that an increased uptake of spermidine as a caloric restriction mimic can reduce overall mortality associated with cancers. The possible mechanisms between spermidine and cancer development may be related to the precise regulation of polyamine metabolism, anti-cancer immunosurveillance, autophagy, and apoptosis. Increased intake of polyamine seems to suppress tumorigenesis, but appears to accelerate the growth of established tumors. Based on these observations and the absolute requirement for polyamines in tumor growth, spermidine could be a rational target for chemoprevention and clinical therapeutics of cancers.

Accuracy Improvement of Binocular Vision Measurement System for Slope Deformation Monitoring.

This paper studies the limitations of binocular vision technology in monitoring accuracy. The factors affecting the surface displacement monitoring of the slope are analyzed mainly from system structure parameters and environment parameters. Based on the error analysis theory, the functional relationship between the structure parameters and the monitoring error is studied. The error distribution curve is obtained through laboratory testing and sensitivity analysis, and parameter selection criteria are proposed. Corresponding image optimization methods are designed according to the error distribution curve of the environment parameters, and a large number of tests proved that the methods effectively improved the measurement accuracy of slope deformation monitoring. Finally, the reliability and accuracy of the proposed system and method are verified by displacement measurement of a slope on site.

An annotated street view image dataset for automated road damage detection.

Road damage is a great threat to the service life and safety of roads, and the early detection of pavement damage can facilitate maintenance and repair. Street view images serve as a new solution for the monitoring of pavement damage due to their wide coverage and regular updates. In this study, a road pavement damage dataset, the Street View Image Dataset for Automated Road Damage Detection (SVRDD), was developed using 8000 street view images acquired from Baidu Maps. Based on these images, over 20,000 damage instances were visually recognized and annotated. These instances were distributed in five administrative districts of Beijing City. Ten well-established object detection algorithms were trained and assessed using the SVRDD dataset. The results have demonstrated the performances of these algorithms in the detection of pavement damages. To the best of our knowledge, SVRDD is the first public dataset based on street view images for pavement damages detection. It can provide reliable data support for future development of deep learning algorithms based on street view images.

Hydrogel-based immunoregulation of macrophages for tissue repair and regeneration.

The rational design of hydrogel materials to modulate the immune microenvironment has emerged as a pivotal approach in expediting tissue repair and regeneration. Within the immune microenvironment, an array of immune cells exists, with macrophages gaining prominence in the field of tissue repair and regeneration due to their roles in cytokine regulation to promote regeneration, maintain tissue homeostasis, and facilitate repair. Macrophages can be categorized into two types: classically activated M1 (pro-inflammatory) and alternatively activated M2 (anti-inflammatory and pro-repair). By regulating the physical and chemical properties of hydrogels, the phenotypic transformation and cell behavior of macrophages can be effectively controlled, thereby promoting tissue regeneration and repair. A full understanding of the interaction between hydrogels and macrophages can provide new ideas and methods for future tissue engineering and clinical treatment. Therefore, this paper reviews the effects of hydrogel components, hardness, pore size, and surface morphology on cell behaviors such as macrophage proliferation, migration, and phenotypic polarization, and explores the application of hydrogels based on macrophage immune regulation in skin, bone, cartilage, and nerve tissue repair. Finally, the challenges and future prospects of macrophage-based immunomodulatory hydrogels are discussed.

Polyphenolic-modified cellulose acetate membrane for bone regeneration through immunomodulation.

To enhance the bioactivity of cellulosic derivatives has become an important strategy to promote their value for clinical applications. Herein, protocatechualdehyde (PCA), a polyphenolic molecule, was used to modify a cellulose acetate (CA) membrane by combining with metal ions to confer an immunomodulatory activity. The PCA-modified CA membrane has shown a significant radical scavenging activity, thereby suppressed the inflammatory response and created a favorable immune microenvironment for osteogenesis and mineralization. Moreover, addition of metal ions could further stimulate the osteogenic differentiation of stem cells and accelerate bone regeneration both in vitro and in vivo. This study may provide a strategy to promote the immunomodulatory activity of cellulose-based biomaterials for bone regeneration.

Techniques for increasing the yield of stem cell-derived exosomes: what factors may be involved?

Exosomes are nano-scale extracellular vesicles secreted by cells and constitute an important part in the cell-cell communication. The main contents of the exosomes include proteins, microRNAs, and lipids. The mechanism and safety of stem cell-derived exosomes have rendered them a promising therapeutic strategy for regenerative medicine. Nevertheless, limited yield has restrained full explication of their functions and clinical applications To address this, various attempts have been made to explore the up- and down-stream manipulations in a bid to increase the production of exosomes. This review has recapitulated factors which may influence the yield of stem cell-derived exosomes, including selection and culture of stem cells, isolation and preservation of the exosomes, and development of artificial exosomes.