Numerical Simulation of the Influence of Water Flow on the Piers of a Bridge for Different Incidence Angles

A two-dimensional mathematical model is used to simulate the influence of water flow on the piers of a bridge for different incidence angles.In particular,a finite volume method is used to discretize the Navier-Stokes control equations and calculate the circumferential pressure coefficient distribution on the bridge piers’surface.The results show that the deflection of the flow is non-monotonic.It first increases and then decreases with an increase in the skew angle.

干细胞球聚体微针促进糖尿病创面愈合

根据世界卫生组织统计,全球范围内有超过4亿人患有糖尿病^([1]).由于其发病机制涉及神经病变、血管病变和免疫功能受损等多个因素,患者易出现皮肤感觉减退、血液供应不足及免疫功能下降等问题^([2]).经统计,约15%~25%的糖尿病患者会并发难以愈合的皮肤溃疡,即糖尿病溃疡,好发于患者下肢、足部或其他容易受压的部位^([3]).

基于植物光合系统赋予人体细胞能量的再生医学

To fulfill the long-held dream of human beings to stay health and extend life,regenerative medicine has merged as the future medical direction.Generally,the regenerative medicine aims to repairing or replacing the dysfunctional organs caused by diseases or aging[1].The phenomenon of regeneration is widespread among natural species[2].Many animals are born with the ability to repair severely defected tissues or regenerate partially damaged organs.For example,geckoes can grow back their severed tails without leaving any scars;earthworms are able to regenerate new bodies on the cut surface after being chopped.

3D-Printed Janus Piezoelectric Patchesfor Sonodynamic Bacteria Elimination and Wound Healing

Management of infected wounds has raised worldwide concerns.Attempts in this field focus on the development of intelligent patches for improving the wound healing.Here,inspired by the cocktail treatment and combinational therapy stratagem,we present a novel Janus piezoelectric hydrogel patch via 3-dimensional printing for sonodynamic bacteria elimination and wound healing.The top layer of the printed patch was poly(ethylene glycol)diacrylate hydrogel with gold-nanoparticle-decorated tetragonal barium titanate encapsulation,which realizes the ultrasound-triggered release of reactive oxygen species without leaking nanomaterials.The bottom layer is fabricated with methacrylate gelatin and carries growth factors for the cell proliferation and tissue reconstruction.Based on these features,we have demonstrated invivo that the Janus piezoelectric hydrogel patch can exert substantial infection elimination activity under the excitation of ultrasound,and its sustained release of growth factors can promote tissue regeneration during wound management.These results indicated that the proposed Janus piezoelectric hydrogel patch had practical significance in sonodynamic infection alleviation and programmable wound healing for treating different clinical diseases.

Emerging diagnostic and therapeutic technologies based on ultrasound-triggered biomaterials

Ultrasound(US)is a kind of acoustic wave with frequency higher than 20 kHz.Learning from the echo detection ability of bats and dolphins,scientists applied US for clinical imaging by sending out US waves and detecting echoes with shifted intensities and frequencies from human tissue.US has long played a critical role in noninvasive,real-time,low-cost and portable diagnostic imaging.With the in-depth study of US in multidisciplinary fields,US and US-responsive materials have shown practical value in not only disease diagnosis,but also disease treatment.In this review,we introduce the recently proposed and representative US-responsive materials for biomedical applications,including diagnostic and therapeutic applications.We focused on US-mediated physicochemical therapies,such as sonodynamic therapy,high-intensity focused US ablation,sonothermal therapy,thrombolysis,etc,and US-controlled delivery of chemotherapeutics,gases,genes,proteins and bacteria.We conclude with the current challenges facing the clinical translation of smart US-responsive materials and prospects for the future development of US medicine.

Christmas Tree-Shaped Microneedles as FOLFIRINOX Spatiotemporal Delivery System for Pancreatic Cancer Treatment

As an effective combination chemotherapy,FOLFIRINOX regimen(fluorouracil,leucovorin,irinotecan,and oxaliplatin)has shown definite antitumor eficacy for treating pancreatic cancer(PC)nowadays.However,the traditional systematic administration of these chemotherapeutics limits the drug targeting and causes unwanted effects.

Ultrasound-responsive matters for biomedical applications

Ultrasound(US)is a biofavorable mechanical wave that has shown practical significance in biomedical fields.Due to the cavitation effect,sonoluminescence,sonoporation,pyrolysis,and other biophysical and chemical effects,a wide range of matters have been elucidated to be responsive to the stimulus of US.This review addresses and discusses current developments in US-responsive matters,including US-breakable intermolecular conjugations,US-catalytic sonosensitizers,fluorocarbon compounds,microbubbles,and US-propelled micro-and nanorobots.Meanwhile,the interactions between US and advanced matters create various biochemical products and enhanced mechanical effects,leading to the exploration of potential biomedical applications,from US-facilitated biosensing and diagnostic imaging to US-induced therapeutic applications and clinical translations.Finally,the current challenges are summarized and future perspectives on US-responsive matters in biomedical applications and clinical translations are proposed.

Liver spheroids on chips as emerging platforms for drug screening

Liver plays a critical role in drug metabolism and nowadays multi-cellular culture systems aiming at imitating liver-specific morphology and functionality are advancing robustly.Numerous immortalized or stem cell-induced hepatic cell lines have been investigated to enhance the hepatic phenotype in establishing co-culture systems.Owing to the robust progresses of microtechnology and bioengineering,two-dimensional(2D)co-cultures such as sandwich culture and micropatterned co-culture systems have emerged.Controllably arranging the hepatocytes and fibroblasts allows bio-mimic homotypic and heterotypic interactions,and the miniaturized co-culture platform realizes high-throughput and sensitive drug screening.Yet,to address the rapid dedifferentiation and the decreased maintenance of hepatic functions existing in 2D cellular systems,various three-dimensional(3D)and dynamic hepatocyte co-culturing formats have been established to obtain more physiologically relevant liver microsystems and prolonged hepatic functionalities,such as spheroid barcodes,liver organoids,bioengineered hepatic spheroids,and microfluidic perfused liver-on-a-chip.In this review,we first introduce the typical structural color spheroid barcodes which facilitate multiple screening and testing.Then we sketch various advances in liver-imitating cellular co-culture protocols through representative examples.Meanwhile,we summarize current difficulties and propose the prospects of bioengineered liver-on-barcode systems for reliable and high-throughput drug screening.

孙景尧（英文）

Jingyao Sun is the pioneer and founder of Chinese comparative literature,and he made an indelible contribution to the development of Chinese comparative literature.Professor Sun was born in Shanghai in 1943.He graduated from Fudan University

Developing tissue engineering strategies for liver regeneration

The regenerative function of liver can be destroyed by viral infection,drug poisoning and tumorigenesis,resulting in irreversible damage.Numerous approaches in promoting liver repair intend to replace liver transplantation,which is faced with a shortage of donors.Owing to the significant advantages in cell programming and bioscaf-fold engineering,liver tissue engineering is considered to be the most promising alternative for mimicking liver microstructure,maintaining hepatic function or implanting whole liver.Cell sources gradually develop from pri-mary hepatocytes,tumor cells,stem cell-induced cells to multiple cell coculture formats,spheroids and organoids,which have realized the improvement of cell function,overcome the problem of large-scale cell expansion and avoid the risk of immune rejection.Scaffolds,biocompatible materials are applied as cell carriers,and decel-lularized scaffolds and three-dimensional bioprinting liver pipeline structures are also used to accelerate cell colonization and proliferation.We enumerate sufficient research concerning liver tissue engineering in this re-view,including single and multiple cell sources,implantable and extracorporeal scaffold materials,and so on,providing critical conclusions and future implications of tissue engineering in liver regenerative applications.

基于压印细胞片组装的仿生肝小叶

Liver-tissue engineering has proven valuable in treating liver diseases,but the construction of liver tissues with high fidelity remains challenging.Here,we present a novel three-dimensional(3D)-imprinted cell-sheet strategy for the synchronous construction of biomimetic hepatic microtissues with high accuracy in terms of cell type,density,and distribution.To achieve this,the specific composition of hepatic cells in a normal human liver was determined using a spatial proteogenomics dataset.The data and biomimetic hepatic micro-tissues with hexagonal hollow cross-sections indicate that cell information was successfully generated using a homemade 3D-imprinted device for layer-by-layer imprinting and assembling the hepatic cell sheets.By infiltrating vascular endothelial cells into the hollow section of the assembly,biomimetic hepatic microtissues with vascularized channels for nutrient diffusion and drug perfusion can be obtained.We demonstrate that the resultant vascularized biomimetic hepatic micro-tissues can not only be integrated into a microfluidic drug-screening liver-on-a-chip but also assembled into an enlarged physiological structure to promote liver regeneration.We believe that our 3D-imprinted cell sheets strategy will open new avenues for biomimetic microtissue construction.