An Experimental and Numerical Study on the Ballistic Performance of Multi-Layered Moderately-Thick Metallic Targets against 12.7-mm Projectiles

Themain goal of this work is to study the ballistic performance ofmulti-layered moderately-thick metallic targets.Several target configurations have been considered in thiswork,with various types of interlayer connection(spaced,contacted and adhesive)and the number of layers(four and eight),and the influence of target configurations on ballistic performance has been studied experimentally and numerically.In the experiments,the targets were impacted by 12.7-mm projectiles at a velocity around 820 m/s.The experimental results show that,with similar total thickness,the contacted and adhesive targets exhibit better ballistic performance than the monolithic targets,and the four-layered targets are better than the eight-layered targets with the same connection type.To explore the ballistic resistance mechanism,numerical method has been used to simulate the penetration process of each target.The numerical results indicate that petal formation and friction have significant influence on targets’ballistic performance.Friction has stronger influence on themulti-layered targets than on themonolithic ones.According to the numerical results,about 14%of projectile’s initial kinetic energy is dissipated by friction during penetrating the four-layered contacted target,which is proved to be the most effective type of target studied in thiswork.The results also indicate that,in contrast to common understanding,friction plays an important role even when the impact velocity is significantly higher than the ballistic limit.The outcome of this work may provide useful information for a better understanding of ballistic resistant mechanisms and more efficient utilization of multi-layered metallic targets in armor structural design.

Modulation of starch synthesis in Arabidopsis via phytochrome B-mediated light signal transduction

Starch is a major storage carbohydrate in plants and is critical in crop yield and quality.Starch synthesis is intricately regulated by internal metabolic processes and external environmental cues;however,the precise molecular mechanisms governing this process remain largely unknown.In this study,we revealed that high red to far-red(high R:FR)light significantly induces the synthesis of leaf starch and the expression of synthesis-related genes,whereas low R:FR light suppress these processes.Arabidopsis phytochrome B(phyB),the primary R and FR photoreceptor,was identified as a critical positive regulator in this process.Downstream of phyB,basic leucine zipper transcription factor ELONGATED HYPOCOTYL5(HY5)was found to enhance starch synthesis,whereas the basic helix-loop-helix transcription factors PHYTOCHROME INTERACTING FACTORs(PIF3,PIF4,and PIF5)inhibit starch synthesis in Arabidopsis leaves.Notably,HY5 and PIFs directly compete for binding to a shared G-box cis-element in the promoter region of genes encoding starch synthases GBSS,SS3,and SS4,which leads to antagonistic regulation of their expression and,consequently,starch synthesis.Our findings highlight the vital role of phyB in enhancing starch synthesis by stabilizing HY5 and facilitating PIFs degradation under high R:FR light conditions.Conversely,under low R:FR light,PIFs predominantly inhibit starch synthesis.This study provides insight into the physiological and molecular functions of phyB and its downstream transcription factors HY5 and PIFs in starch synthesis regulation,shedding light on the regulatory mechanism by which plants synchronize dynamic light signals with metabolic cues to module starch synthesis.

Bioinspired mineral-in-shell nanoarchitectonics:Functional empowerment of mineral precursors for guiding intradentinal mineralization

Effective mineralization of biological structures poses a significant challenge in hard tissue engineering as it necessitates overcoming geometric complexities and multistep biomineralization processes.In this regard,we propose“mineral-in-shell nanoarchitectonics”,inspired by the nanostructure of matrix vesicles,which can influence multiple mineralization pathways.Our nanostructural design empowers mineral precursors with tailorable properties through encapsulating amorphous calcium phosphate within a multifunctional tannic acid(TA)and silk fibroin(SF)nanoshell.The bioinspired nanosystem facilitates efficient recruitment of mineral precursors throughout the dentin structures,followed by large-scale intradentinal mineralization both in vitro and in vivo,which provides persistent protection against external stimuli.Theoretical simulations combined with experimental studies attribute the success of intradentinal mineralization to the TA-SF nanoshell,which exhibits a strong affinity for the dentin structure,stabilizing amorphous precursors and thereby facilitating concomitant mineral formation.Overall,this bioinspired mineral-in-shell nanoarchitectonics shows a promising prospect for hard tissue repair and serves as a blueprint for next-generation biomineralization-associated materials.

Ectopic mineralization-inspired cell membrane-based matrix vesicle analogs for in-depth remineralization of dentinal tubules for treating dentin hypersensitivity

The invasion of etched dentinal tubules(DTs)by external substances induces dentin hypersensitivity(DH).The deep and compact occlusion of DTs is highly desirable for treating DH but still challenging due to the limited penetrability and mineralization capacities of most current desensitizers.Matrix vesicles(MVs)participate in the regulation of ectopic mineralization.Herein,ectopic MV analogs are prepared by employing natural cell membranes to endow mineral precursors with natural biointerfaces and integrated biofunctions for stimulating dentin remineralization.The analogs quickly access DTs(>20μm)in only 5 min and further penetrate deep into the interior of DTs(an extraordinary~200μm)in 7 days.Both in vitro and in vivo studies confirm that the DTs are efficiently sealed by the newly formed minerals(>50μm)with excellent resistance to wear and acid erosion,which is significantly deeper than most reported values.After repair,the microhardness of the damaged dentin can be recovered to those of healthy dentin.For the first time,cell membrane coating nanotechnology is used as a facile and efficient therapy for in-depth remineralization of DTs in treating DH with thorough and long-term effects,which provides insights into their potential for hard tissue repair.

Alum colloid encapsulated insideβ-glucan particles enhance humoral and CTL immune responses of MUC1 vaccine

We have developed a MUC1 antigen-based antitumor vaccine loaded on alum colloid encapsulated insideβ-glucan particles(GP-Al).The constructed vaccine induced strong MUC1 antigen specific Ig G antibody titers and enhanced CD^(8+)T cells cytotoxic effect to kill tumor cells.These results indicated that GP-Al can be served as an efficient delivery system and adjuvant for the development of cancer vaccines especially small molecule antigens based cancer vaccines.