According to the World Health Organization, more than 400 million people worldwide suffer from diabetes Due to its pathogenesis involving multiple factors such as neuropathy, vascular disease, and impaired immune function, patients are prone to problems such as decreased skin sensation, insufficient blood supply, and decreased immune function According to statistics, about 15%~25% of diabetes patients will have skin ulcers that are difficult to heal, that is, diabetes ulcers, which tend to occur in patients' lower limbs, feet or other parts prone to pressure At present, the main methods to promote the healing of diabetes ulcers include wound management, infection control, negative pressure suction, application of growth factors, skin substitutes and skin flaps However, because of its complex pathogenesis, the recurrence rate and disability rate of diabetes ulcer are still high, so more effective treatment methods need to be developed In recent years, as a cutting-edge treatment method, stem cell therapy has been widely studied and applied in many fields, and its therapeutic value in diabetes ulcer has also been widely verified Stem cells come from various sources, including hematopoietic stem cells, mesenchymal stem cells, neural stem cells, human embryonic stem cells, and induced pluripotent stem cells Among them, mesenchymal stem cells have a wide range of sources and multi-directional differentiation potential, which helps promote wound repair and tissue regeneration; In addition, mesenchymal stem cells can also release growth factors and cytokines, promote angiogenesis, reduce inflammatory reactions, and improve wound healing ability Therefore, mesenchymal stem cells have broad application prospects in the field of regenerative medicine The application of stem cells has a significant impact on the therapeutic effect of diseases At present, the application methods of stem cells are mainly divided into direct injection and tissue engineering construction Direct injection refers to the direct injection of stem cells into the area around an ulcer or wound to promote wound repair Tissue engineering refers to the cultivation of stem cells in vitro and the construction of tissue engineered composite materials, followed by the implantation of stem cell composite materials into wounds to achieve tissue repair and regeneration Research has shown that due to the complex inflammatory microenvironment on the wound surface, directly injected stem cells often quickly become inactive, resulting in low cell retention rate and poor therapeutic effect To solve this problem, scientists often use tissue engineering technology to develop various new cell scaffolds or carriers as stem cell delivery strategies Cell scaffolds and cell carriers can provide biological and physical support for stem cells to reduce their loss and inactivation during transportation It is worth noting that cell scaffolds with special shapes and structures have been proven to further enhanc
The electrocatalytic decomposition of water to produce hydrogen driven by renewable energy is an effective way to achieve hydrogen economy and is of great significance for achieving the dual carbon goal. However, the oxygen evolution half reaction (OER) located at the anode involves multi-step four electron transfer, slow kinetics, and the presence of high overpotential seriously restricts the energy conversion efficiency of electrolytic water to produce hydrogen At present, high-performance anode materials mainly rely on precious metal based IrO2 and RuO2 catalysts. Therefore, the development of non precious metal catalysts with high catalytic activity and excellent stability is a long-term challenge for the large-scale application of hydrogen production by electrolysis of water In recent years, perovskite oxides have attracted widespread attention due to their adjustable composition, high electron/ion conductivity, good catalytic activity, and low material cost In 2017, Professor Shaoyang's research group at the Massachusetts Institute of Technology based on perovskite oxide SrCoO3 − δ A new mechanism has been discovered for the involvement of lattice oxygen in OER, namely the lattice oxygen oxidation mechanism (LOM) LOM, due to its involvement in direct O-O coupling, breaks the dependence of HO * and HOO * in traditional adsorption evolution mechanisms (AEM), bringing the Gibbs free energy of each OER step closer to the theoretical value, thus exhibiting higher catalytic activity Due to the involvement of lattice oxygen escape in LOM, a certain amount of oxygen vacancies (VOs) are inevitably formed on the catalyst surface Interestingly, recent studies have shown that oxygen vacancies play a crucial role in regulating the electronic structure of catalysts and driving LOM Although oxygen defect regulation based on ion doping and heat treatment has been proven to be an effective strategy for activating LOM, it has not fundamentally changed the rigid lattice of metal oxygen bonds, resulting in higher VOs formation energy and OER Gibbs free energy changes in the catalyst Compared to perovskite oxides, metal halide perovskite exhibits soft lattice properties due to the weak bonding properties between constituent elements, providing greater structural flexibility for triggering LOM Due to the poor stability of halide perovskite in water and polar solvents, researchers usually use various matrices (such as organic polymers, metal/non-metallic oxides, etc.) as external coatings to isolate halide perovskite nanocrystals from water, oxygen, etc. to improve the water stability of perovskite However, considering the high current density of industrial water electrolysis for hydrogen production and the requirements for long-term durability of catalysts, the lack of stability of halide perovskite water in composite materials and the lack of exposed catalytic active sites are the main obstacles to their electrocatalytic water oxidation Molecular sieves are a t
Wenjun Wang, Li Zheng, Hong Cheng, Xiaowei Xu, Bo Meng
{"title":"机器学习在可穿戴智能传感系统中的应用与进展","authors":"Wenjun Wang, Li Zheng, Hong Cheng, Xiaowei Xu, Bo Meng","doi":"10.1360/tb-2023-0636","DOIUrl":"https://doi.org/10.1360/tb-2023-0636","url":null,"abstract":"","PeriodicalId":10230,"journal":{"name":"Chinese Science Bulletin","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46477844","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
{"title":"Chemical relics of very massive first-generation stars from LAMOST","authors":"Q. Xing, G. Zhao","doi":"10.1360/tb-2023-0586","DOIUrl":"https://doi.org/10.1360/tb-2023-0586","url":null,"abstract":"","PeriodicalId":10230,"journal":{"name":"Chinese Science Bulletin","volume":" ","pages":""},"PeriodicalIF":0.0,"publicationDate":"2023-07-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48515624","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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