Visualizing Complex Anatomical Structure in Bamboo Nodes Based on X-ray Microtomography

In recent years,bamboo has been widely used in a broad range of applications,a thorough understanding of the structural characteristics of bamboo nodes is essential for better processing and manufacturing of biomimetic materials.This study investigated the complex anatomical structure for the nodes of two bamboo species,Indocalamus latifolius(Keng)McClure and Shibataea chinensis Nakai,using a high-resolution X-ray microtomography(μCT).The results show that the vascular bundle system in the nodal region of I.latifolius and S.chinensis is a net-like structure composed of horizontal and axial vascular bundles.Furthermore,the fiber sheath surrounding metaxylem vessels tended to be shorter in the tangential direction.This structure of bamboo nodes facilitates the tangential and axial transport of moisture and nutrients.The anatomical structure of I.latifolius and S.chinensis nodes has obvious differences,especially in the arrangement of vascular bundles.Vascular bundle frequency was significantly higher in S.chinensis nodes than in I.latifolius nodes.These findings indicate thatμCT is a nondestructive three-dimensional imaging method that can used to examine the anatomical structure of bamboo nodes.

The recent development of soft x-ray interference lithography in SSRF

This paper introduces the recent progress in methodologies and their related applications based on the soft x-ray interference lithography beamline in the Shanghai synchrotron radiation facility.Dual-beam,multibeam interference lithography and Talbot lithography have been adopted as basic methods in the beamline.To improve the experimental performance,a precise real-time vibration evaluation system has been established;and the lithography stability has been greatly improved.In order to meet the demands for higher resolution and practical application,novel experimental methods have been developed,such as high-order diffraction interference exposure,high-aspect-ratio and large-area stitching exposure,and parallel direct writing achromatic Talbot lithography.As of now,a 25 nm half-pitch pattern has been obtained;and a cm2 exposure area has been achieved in practical samples.The above methods have been applied to extreme ultraviolet photoresist evaluation,photonic crystal and surface plasmonic effect research,and so on.

Nonuniform self-imaging of achromatic Talbot lithography

Achromatic Talbot lithography(ATL)with high resolution has been demonstrated to be an excellent technique for large area periodic nano-fabrication.In this work,the uniformity of pattern distribution in ATL was studied in detail.Two ATL transmission masks with^50%duty cycle in a square lattice were illuminated by a spatial coherent broadband extreme ultraviolet beam with a relative bandwidth of 2.38%.Nonuniform dot size distribution was observed by experiments and finite-difference time-domain simulations.The sum of the two kinds of diffraction patterns,with different lattice directions(45°rotated)and different intensity distributions,results in the final nonuniform pattern distribution.

Quick photofabrication of functional nanospheres from de novo designed peptides for NIR fluorescence and MR imaging

Combining the noncovalent and covalent interactions,a series of peptide amphiphiles were designed de novo and synthesized to architect functional assemblies by means of photochemistry.The strand of peptide sequence was structurally capped with photoactive tyrosine-tyrosine(YY)motifs at both termini,and the spacing was filled by alternating of hydrophilic D(L-aspartate)and hydrophobic X(ε-aminocaproic acid)structure.Upon visible-light irradiation,these de novo designed peptides underwent rapid photocrosslinking within merely 10 min.Interestingly,the modulation of alternating D-X pairs in occupying spacer would adjust molecular amphiphilicity,regulate charge distribution,and control particle size and loading capacity of peptide nanospheres(PNS)in aqueous media.With entirely peptide-based matrix,this PNS system could host cationic indicators of fluorescent rhodamine and magnetic GdIII for exemplar near infrared(NIR)fluorescence and magnetic resonance(MR)imaging,which paves a pathway to biomaterial and biomedical applications using de novo designed peptides.