Xi'an Jiaotong University

About: Xi'an Jiaotong University is a education organization based out in Xi'an, China. It is known for research contribution in the topics: Heat transfer & Dielectric. The organization has 85440 authors who have published 99682 publications receiving 1579683 citations. The organization is also known as: '''Xi'an Jiaotong University''' & Xi'an Jiao Tong University.

Magnetic Hydrogels and Their Potential Biomedical Applications

Abstract: Hydrogels find widespread applications in biomedical engineering due to their hydrated environment and tunable properties (e.g., mechanical, chemical, biocompatible) similar to the native extracellular matrix (ECM). However, challenges still exist regarding utilizing hydrogels in applications such as engineering 3D tissue constructs and active targeting in drug delivery, due to the lack of controllability, actuation, and quick-response properties. Recently, magnetic hydrogels have emerged as a novel biocomposite for their active response properties and extended applications. In this review, the state-of-the-art methods for magnetic hydrogel preparation are presented and their advantages and drawbacks in applications are discussed. The applications of magnetic hydrogels in biomedical engineering are also reviewed, including tissue engineering, drug delivery and release, enzyme immobilization, cancer therapy, and soft actuators. Concluding remarks and perspectives for the future development of magnetic hydrogels are addressed.

Fluorination-enabled optimal morphology leads to over 11% efficiency for inverted small-molecule organic solar cells

Abstract: Solution-processable small molecules for organic solar cells have attracted intense attention for their advantages of definite molecular structures compared with their polymer counterparts. However, the device efficiencies based on small molecules are still lower than those of polymers, especially for inverted devices, the highest efficiency of which is <9%. Here we report three novel solution-processable small molecules, which contain π-bridges with gradient-decreased electron density and end acceptors substituted with various fluorine atoms (0F, 1F and 2F, respectively). Fluorination leads to an optimal active layer morphology, including an enhanced domain purity, the formation of hierarchical domain size and a directional vertical phase gradation. The optimal morphology balances charge separation and transfer, and facilitates charge collection. As a consequence, fluorinated molecules exhibit excellent inverted device performance, and an average power conversion efficiency of 11.08% is achieved for a two-fluorine atom substituted molecule.

Metal halide perovskite nanostructures for optoelectronic applications and the study of physical properties

Abstract: Nanostructures of inorganic semiconductors have revolutionized many areas of electronics, optoelectronics and photonics. The controlled synthesis of semiconductor nanostructures could lead to novel physical properties, improved optoelectronic device performance and new areas for exploration. Lead halide perovskites have recently excited the photovoltaic research community owing to their high solar-conversion efficiencies and ease of solution processing; they also hold great promise for optoelectronic applications, such as light-emitting diodes and lasers. In this Review, we summarize recent developments in the synthesis and characterization of metal halide perovskite nanostructures with controllable compositions, dimensionality, morphologies and orientations. We examine the advantageous optical properties, improved stability and potential optoelectronic applications of these 1D and 2D single-crystal perovskite nanostructures and compare them with those of bulk perovskites and nanostructures of conventional semiconductors. Studies in which perovskite nanostructures have been used to study the fundamental physical properties of perovskites are also highlighted. Finally, we discuss the challenges in realizing halide perovskite nanostructures for optoelectronic and photonic applications and offer our perspectives on future opportunities and research directions. Metal halide perovskite nanostructures are promising materials for optoelectronic applications. In this Review, we discuss the synthesis and properties of 1D and 2D single-crystal perovskite nanostructures, examine potential optoelectronic applications and highlight recent studies in which these nanostructures have been used to study the fundamental properties of perovskites.

Gut microbiota and intestinal FXR mediate the clinical benefits of metformin.

Abstract: The anti-hyperglycemic effect of metformin is believed to be caused by its direct action on signaling processes in hepatocytes, leading to lower hepatic gluconeogenesis. Recently, metformin was reported to alter the gut microbiota community in humans, suggesting that the hyperglycemia-lowering action of the drug could be the result of modulating the population of gut microbiota. However, the critical microbial signaling metabolites and the host targets associated with the metabolic benefits of metformin remained elusive. Here, we performed metagenomic and metabolomic analysis of samples from individuals with newly diagnosed type 2 diabetes (T2D) naively treated with metformin for 3 d, which revealed that Bacteroides fragilis was decreased and the bile acid glycoursodeoxycholic acid (GUDCA) was increased in the gut. These changes were accompanied by inhibition of intestinal farnesoid X receptor (FXR) signaling. We further found that high-fat-diet (HFD)-fed mice colonized with B. fragilis were predisposed to more severe glucose intolerance, and the metabolic benefits of metformin treatment on glucose intolerance were abrogated. GUDCA was further identified as an intestinal FXR antagonist that improved various metabolic endpoints in mice with established obesity. Thus, we conclude that metformin acts in part through a B. fragilis-GUDCA-intestinal FXR axis to improve metabolic dysfunction, including hyperglycemia.