Trends and Prospects of Stem Cell Research in China

Great progresses have been made in fundamental and clinical stem cell research in China in recent years. The official policy on stem cells, which was announced in 2015, seems as the spring of stem cell therapy in China. However, the regulation, governance, and management of clinical expectations are still challenging. This review summarized the current stem cell research and development in the field, as well as its rapidly evolving commercial, regulatory and ethical environment in China. As expected, the prospects of stem cells in China look prospective.

Synthesis and antibacterial activity of novel[1,2,4]triazolo[3,4-h][1,8]naphthyridine-7-carboxylic acid derivatives

Novel tricyclic fluoroquinolones,[1,2,4]triazolo[3,4-h][1,8]naphthyridine-8-one-7-carboxylic acid derivatives 4a-4h bearing carrying a functional Mannich-base moiety at the C-8 position,were synthesized and evaluated for their antimicrobial activity.The results showed that some compounds with a piperazine side chain exhibited comparable or better antibacterial activity than comparator cirprofloxacin.Furthermore,the targeted compounds also displayed a broad spectrum of activity against resistant strains including both Gram-negative and Gram-positive bacteria.In particular,compound 4h showed an MIC of 0.25 μg/mL in antibacterial assay against multiple drug-resistant Escherichia coli,which represents an about 30-fold increase of potency compared to ciprofloxacin.Thus,their excellent antibacterial activity against resistant strains suggests that triazole-fused fluoroquinolones warrant further optimization as novel anti-infective chemotherapies.

Submicron single-crystalline LiNi_(0.5)Mn_(1.5)O_(4) cathode with modulated Mn^(3+) content enabling high capacity and fast lithium-ion kinetics

Disordered single-crystalline LiNi_(0.5)Mn_(1.5)O_(4)(LNMO)cathode materials with different Mn^(3+)contents were prepared by a simple temperature control strategy of a solid-state reaction.The effects of the mutual modulation of the Mn^(3+) content and the bulk microstructure on the crystal structure and electrochemical properties of LNMO were systematically investigated.Results showed that a suitable Mn^(3+) content can enhance the structural stability and alleviate structural degradation and capacity fading.The excellent performance originates from the simultane-ous inhibition of microcrack formation and side reaction with electrolytes,ensuring the rapid diffusion of Li+during extraction and insertion.Consequently,the LNMO-800 sample delivers an excellent cycling stability with a capacity retention of 98.37%after 200 cycles,remarkable rate capacity of 115 mAh·g^(-1) at 10.0C,and rapid Li+diffusion coefficient of 4.43×10^(-9)cm^(2)·s^(-1).This work will allow for a deeper understanding of the coupling effect between Mn^(3+)content and bulk microstructure,especially in the design and development of Mn-based cathode materials.

Design, synthesis and antitumor activity of C3/C3 bis-fluoroquonolones cross-linked with [1,2,4]triazolo[3,4-b] [1,3,4]thiadiazole

To contribute to the development of an efficient method for the conversion of antibacterial fluoroquinolones to antitumor fluoroquinolones,a series of C3/C3 bis-fluoroquinolone fused heterocycles cross-linked with a[1,2,4]-triazolo[3,4-b][1,3,4]-thiadiazole core as a common bioisostere of two carboxylic acid groups was designed and synthesized as their hydrochloride salts.Structures were characterized by elemental analysis and spectral data and their in vitro antitumor activity against L1210,CHO and HL60 cell lines was screened by determination of their IC50 values in the methylthiazole trazolium(MTT)assay.Two compounds were highly potent against the HL60 cell line and represent promising lead compounds for future development.

Depositing natural stibnite on 3D TiO_(2) nanotube array networks as high-performance thin-film anode for lithium-ion batteries

Three-dimensional(3D) thin-film electrodes are promising solution to the volume change of active materials in lithium-ion batteries.As a conductive current collector,the 3D TiO_(2) nanotube array networks(TNAs) have a one-dimensional stable electronic conductive path and increase the adhesion between the current collector and raw material,thereby improving the cycle stability of active materials.In this study,a novel 3D-TNAs@Sb_(2)S_(3) anode was fabricated by directly depositing natural stibnite onto3D TNAs.The adhesion of Sb_(2)S_(3) particles to the substrate was enhanced due to the large surface area provided by 3D-TNAs.Moreover,the porous layered structure composed of Sb_(2)S_(3) nanoparticles relieved the stress generated during lithiation and adapted to the volume change of Sb_(2)S_(3) during cycling.Therefore,the resulting composite anode exhibits high cycle and rate performance,reaching0.36 mAh·cm^(-2) after 80 cycles at the galvanostatic rate of1 mA·cm^(-2),with high coulombic efficiency of 98%.

The optimal vaccination strategy to control COVID-19:a modeling study in Wuhan City,China

Background: Reaching optimal vaccination rates is an essential public health strategy to control the coronavirus disease 2019 (COVID-19) pandemic. This study aimed to simulate the optimal vaccination strategy to control the disease by developing an age-specific model based on the current transmission patterns of COVID-19 in Wuhan City, China.Methods: We collected two indicators of COVID-19, including illness onset data and age of confirmed case in Wuhan City, from December 2, 2019, to March 16, 2020. The reported cases were divided into four age groups: group 1, ≤ 14 years old;group 2, 15 to 44 years old;group 3, 44 to 64 years old;and group 4, ≥ 65 years old. An age-specific susceptible-exposed-symptomatic-asymptomatic-recovered/removed model was developed to estimate the transmissibility and simulate the optimal vaccination strategy. The effective reproduction number (R_(eff)) was used to estimate the transmission interaction in different age groups.Results: A total of 47 722 new cases were reported in Wuhan City from December 2, 2019, to March 16, 2020. Before the travel ban of Wuhan City, the highest transmissibility was observed among age group 2 (R_(eff) = 4.28), followed by group 2 to 3 (R_(eff) = 2.61), and group 2 to 4 (R_(eff) = 1.69). China should vaccinate at least 85% of the total population to interrupt transmission. The priority for controlling transmission should be to vaccinate 5% to 8% of individuals in age group 2 per day (ultimately vaccinated 90% of age group 2), followed by 10% of age group 3 per day (ultimately vaccinated 90% age group 3). However, the optimal vaccination strategy for reducing the disease severity identified individuals ≥ 65 years old as a priority group, followed by those 45-64 years old.Conclusions: Approximately 85% of the total population (nearly 1.2 billion people) should be vaccinated to build an immune barrier in China to safely consider removing border restrictions. Based on these results, we concluded that 90% of adults aged 15-64 years should first be vaccinated to prevent transmission in China.