摘要：additive manufacturing,also known as three-dimensional(3D)printing,has attracted increasing attention due to the innovations in materials science and manufacturing over recent decades[1].Recently,innovations in biocompatible materials and biology have enabled the extension of 3D printing techniques into bioadditive manufacturing,which focuses on the fabrication of 3D engineered native-like tissues/organs[2].Currently,bioadditive manufacturing technologies can be categorized into inkjet-based bioprinting,microextrusion-based bioprinting,digital light processing(DLP)bioprinting,electric field-assisted bioprinting,and fused deposition modeling(FDM),to name a few[3,4](Fig.1).Artificial tissues and organs with delicate structures,such as the heart[5]and liver[6],have been successfully fabricated using various bioadditive manufacturing techniques.

摘要：Peripheral nerve injury and nerve conduit manufacturing The global nerve injury repair and regeneration market is expected to reach$9.7 billion by 2025,a compound annual growth rate of 9.1%between 2020 and 2025[1].One component alone,peripheral nerve injury(PNI),encompasses 5 million new cases worldwide every year[2].Although nerve autograft is considered the gold standard for PNI repair,this process sufers because of a short supply of autologous nerves as well as potential harm caused to the *** recent decades,as a promising alternative to autografts。

摘要：An asymptotic existence of balanced incomplete block (BIB) designs and pairwise balanced designs (PBD) has been discussed in [1]-[3]. On the other hand, the existence of additive BIB designs and pairwise additive BIB designs with k = 2?and?λ = 1?has been discussed with direct and recursive constructions in [4]-[8]. In this paper, an asymptotic existence of pairwise additive BIB designs is proved by use of Wilson’s theorem on PBD, and?also for some l?and k the exact existence of l?pairwise additive BIB designs with block size k and?λ = 1?is discussed.

摘要：As an emerging technology to promote the combination of medicine and industry,the three-dimensional(3D)printing has developed rapidly in the fields of orthopedics,while its unique advantages in improving precise treatment still need to be further *** this report,our team have exhibited several classic cases of integrating 3D printing into orthopedic clinical application,thereby further elaborating thoughts and opinions on the significance of 3D printing in the orthopedic clinical application,technical advantages,existing main problems and coping strategies.

摘要：The surface topography of acetabular implants plays a key role in providing cell attachment and *** measurement and characterisation of the surface texture of the cellular scaffold layer on the acetabular cup are very difficult due to the 3D nature of scaffold *** is proposed to use X-ray computed tomography(XCT)to measure the surface texture of an electron beam melting-produced titanium acetabular *** surface texture of its cellular scaffold is evaluated using the newly developed 3D surface texture parameters,which allows surface characterisation on 3D triangular mesh *** commonly used height parameters,*** arithmetical mean height Sa,the root mean square height Sq,the skewness Ssk and the kurtosis Sku,are calculated from surface patches extracted from the XCT scanned triangular mesh *** addition,the surface peak density and pit density,which are more related to cell communication and proliferation,are estimated based on the 3D watershed *** Wolf pruning with an empirical threshold 12μm is used to control the over-segmentation.

摘要：Graphic abstract Concept of 3D bioprinting 3D printing,also called additive manufacturing,is a layerby-layer manufacturing method,and it has been implemented in a wide variety of areas.3D printing could be treated as the reverse process of potato cutting,automatically assembling the chips or slicing into a potato[1].When this simple idea is met with biomedical engineering,3D bioprinting is born.

摘要：Orthopedic bone plates are most commonly used for bone fracture fixation for more than 100 *** bone plate design had evolved over time overcoming many challenges such as insufficient strength and excessive plate–bone contact affecting the blood ***,it is only made of two materials,either stainless steel(AISI 316L)or titanium(Ti–6Al–4V).There are two main limitations of metallic bone implants,namely stress shielding and the problem of malocclusion caused by the displacement of the fracture site during *** overcome the two problems,a new bone plate design with the incorporation of auxetic structures is proposed in this *** study aims to use auxetic structure section in the bone plate that would decrease the stiffness of the region,thereby mitigating the stress-shielding effect and at the same time act as a deformable section to enable intra-operative bending for effective alignment while having enough bending strength and *** different auxetic structures namely re-entrant honeycomb and missing rib structures were *** auxetic structure incorporated bone plates were designed,finite element analysis was done,fabricated using direct metal laser sintering technique,and *** results indicate that the re-entrant honeycomb structure incorporated bone plates serve as an effective bone design compared to the conventional bone plate design,in terms of stress shielding and intra-operative bending while offering similar mechanical and bending strength.

摘要：Hybrid Manufacturing combines the advantages of additive Manufacturing (AM)and Subtractive Manufacturing on a single *** previous research has provided a good background of the manufacturing parameters,the analysis is often carried out separately and there is a lack of combined *** purpose of this research is to examine the influence of the main manufacturing parameters involved in AM and subtracfive processes using different ***,the study is focused on the Material Extrusion process concerning the layer height,fill angle and fill density;as well as two factors related to machining,including stepover and pass *** parameters that were examined include the dimension,hardness, flatness,weight and roughness.A mulfifactofial Design of Experiments was proposed with a total of 64 ***,a statistical analysis was carried out to assess the influence of the different groups on the response ***,a decision table presented and facilitated the selection of parameters depending on the desired objectives,leading to a framework that was applied to a case study for *** decision guide could enable designers and engineers to select the best strategy for a specific application,leading to a more efficient approach for manufacturing.

摘要：Polycaprolactone-carboxymethyl cellulose composites have been obtained and used to print porous structures by material *** materials used contained 0,2 and 5% w/w of the carboxymethyl cellulose *** structures have been analyzed in terms of their morphology (including the evaluation of their porosity),mechanical properties under compression load and cell *** affinity has been evaluated by culturing sheep mesenchymal stem cells and analyzing their viability by the Alamar Blue(R)assay at days 1,3,6 and *** results show that composites samples have similar values of porosity and apparent density than pure polycaprolactone ***,samples containing 5%w/w of carboxymethyl cellulose have micropores on the filaments due to a hindered deposition *** characteristic affects the mechanical properties of the structures,so these ones have a mean compression modulus significantly lower than pure polycaprolactone ***, the samples containing 2%w/w of carboxymethyl cellulose show no significant difference with the pure polycaprolactone ones in terms of their mechanical ***,the presence of 2%w/w of additive improves cell proliferation on the surface of the porous *** complementary information,the flow properties of the composite materials were studied and the power law equations at 210℃ obtained,as this temperature was the 3D printing *** equations can be useful for simulation and designing purposes of other manufacturing processes.

摘要：引言　　3D打印，亦称“增材制造”（ additive manufacturing ），是制造业领域正在迅速发展的一项新兴技术，被誉为“具有工业革命意义的制造技术”［1］22。开源硬件②（ open source hardware ）是以类似于开源软件③（ open source soft-ware）的方式设计的硬件，其作用在于鼓励硬件的源代码（即产品设计文件）由硬件设计者、制造者和消费者组成的共享社区内开放分享。从3D打印产业的发展现状来看，正是有了3D 打印设备中的开源硬件（ open source hardware），才使得3D打印机的成本大幅降低，使其从昂贵的、复杂的工业化用途向易于操作、成本低廉的大众化、个性化消费发展［1］27-28。开源硬件许可证是以著作权为基础，构建具有法律约束力的许可协议，并通过许可协议约定源代码的许可方式以及复制、改编行为的界限，规制源代码共享社区中的许可行为和侵权行为。相比开源软件取得的巨大成功，开源硬件仍然裹足不前，缺乏有效和可强制执行的著作权许可协议制约其发展。3D打印技术的出现，为解决开源硬件的这一问题提供了契机。本文拟分析3D打印开源硬件许可证的著作权基础，并探讨3D打印开源硬件的许可方式。