3D Printing of Tough Hydrogel Scaffolds with Functional Surface Structures for Tissue Regeneration

Hydrogel scaffolds have numerous potential applications in the tissue engineering field.However,tough hydrogel scaffolds implanted in vivo are seldom reported because it is difficult to balance biocompatibility and high mechanical properties.Inspired by Chinese ramen,we propose a universal fabricating method(printing-P,training-T,cross-linking-C,PTC&PCT)for tough hydrogel scaffolds to fill this gap.First,3D printing fabricates a hydrogel scaffold with desired structures(P).Then,the scaffold could have extraordinarily high mechanical properties and functional surface structure by cycle mechanical training with salting-out assistance(T).Finally,the training results are fixed by photo-cross-linking processing(C).The tough gelatin hydrogel scaffolds exhibit excellent tensile strength of 6.66 MPa(622-fold untreated)and have excellent biocompatibility.Furthermore,this scaffold possesses functional surface structures from nanometer to micron to millimeter,which can efficiently induce directional cell growth.Interestingly,this strategy can produce bionic human tissue with mechanical properties of 10 kPa-10 MPa by changing the type of salt,and many hydrogels,such as gelatin and silk,could be improved with PTC or PCT strategies.Animal experiments show that this scaffold can effectively promote the new generation of muscle fibers,blood vessels,and nerves within 4 weeks,prompting the rapid regeneration of large-volume muscle loss injuries.

Application of Scaffolding Theory to Higher Vocational Students Classroom Interaction in English Teaching

Scaffolding theory is one of the mature teaching methods of constructivism model . The effective interaction between teachers and students is one characteristic of scaffold teaching. This paper aims at combining scaffolding theory with classroom interaction in teaching higher vocational students English to help students arouse interest and enhance their comprehensive ability in English learning.

Effective Teaching and Learning: Scaffolding in Reading Class

This paper explores a teaching method—scaffolding in reading class, and also studies its background theories and proposes effective plans to carry out the scaffolding method. By this cooperative teaching and learning, students can not only complete teaching activities with the help of the teacher and students themselves, but also cultivate their abilities to use English and think critically.

The “Wrong Love” Between the Zone of Proximal Development and Scaffolding:An Interview With Prof.James P.Lantolf

The zone of proximal development(ZPD) and the scaffolding theory are very different,both in terms of their theoretical origins and connotations,and can even be said to be very different.However,during the development of the two concepts,some scholars have misunderstood them,resulting in the two being mistaken for similar concepts and therefore often confused.Professor James Lantolf from Pennsylvania State University(State College,USA) was interviewed by Professor Lili Qin from Dalian University of Foreign Studies(Dalian,China) and provides an indepth analysis of these issues.The interview begins with the theoretical roots,connotations and definitions of the ZPD and scaffolding concepts,and then unravels the story of how they have been“mistakenly loved for life”,and ultimately it is made clear that the two concepts are completely different in their practical application to language teaching and should not continue to be used interchangeably.

Lexical Chunks as Scaffolding in College English Teaching

Lexical chunks minimize the language learners'burden of memorization and play a very important role in saving language pro cessing efforts so as to improve the learners'language fluency,appropriacy and idiomaticity.Lexical chunks are taken as"scaffolding"in college English teaching to effectively enhance learners'language proficiency.

Undiscovered pathology of transient scaffolding remains a driver of failures in clinical trials

AIM To statistically examine the released clinical trials and meta-analyses of polymeric bioresorbable scaffolds resuming the main accomplishments in the field with a translation to the routine clinical practice. METHODS The statistical power in clinical trials such as ABSORB Japan, ABSORB China, EVERBIO II, AIDA, and few meta-analyses by the post hoc odds ratio-based sample size calculation, and the patterns of artery remodeling published in papers from ABSORB A and B trials were evaluated. RESULTS The phenomenal admiration from the first ABSORB studies in 2006-2013 was replaced by the tremendous disappointment in 2014-2017 due to reported relatively higher rates of target lesion failure(a mean prevalence of 9.16%) and device thrombosis(2.38%) in randomized controlled trials. Otherwise, bioresorbable vascular scaffold(BVS) performs as well as the metallic drugeluting stent(DES) with a trend toward some benefits for cardiac mortality [risk ratio(RR), 0.58-0.94, P > 0.05]. The underpowered design was confirmed for some studies such as ABSORB Japan, ABSORB China, EVERBIO Ⅱ, AIDA trials, and meta-analyses of Polimeni, Collet, and Mahmoud with some unintentional bias(judged by the asymmetrical Funnel plot). Scaffold thrombosis rates with Absorb BRS were comparable with DES performed with a so-called strategy of the BVS implantation with optimized pre-dilation(P), sizing(S) and post-dilation(P)(PSP) implantation(RR, PSP vs no PSP 0.37) achieving 0.35 per 100 patient-years, which is comparable to the RR 0.49 with bare-metal stents and the RR 1.06 with everolimus DES. Both ABSORB Ⅱ and ABSORB Ⅲ trials were powered enough for a five-year follow-up, but the results were not entirely conclusive due to the mostly non-significant fashion of data. The powered metaanalyses were built mostly on statistically poor findings. CONCLUSION The misunderstanding of the pathology of transient scaffolding drives the failures of the clinical trials. More bench studies of the vascular response are required. Several next-generation BVS including multifunctional electronic scaffold grant cardiology with a huge promise to make BVS technology great again.

How to Promote Learner-Learner Scaffolding in ESL Classroom

The current study attempts to investigate learner-learner scaffolding in ESL classroom.Analyzing how learners providing scaffolding with each other,and presenting methods how to promote learner-learner scaffolding.In this paper,discourse analysis methodology utilized to carry out the research.In the study,the data collected from the transcripts of audio and video- recorded interaction during lessons in ESL classrooms at advanced level.The finding indicated that effective scaffolding among learners can promote their metacognition.It is hoped that the present study can serve to raise teachers' awareness of the importance of learner-learner scaffolding in English language teaching and learning.

Insights into Nano-and Micro-Structured Scaffolds for Advanced Electrochemical Energy Storage

Adopting a nano-and micro-structuring approach to fully unleashing the genuine potential of electrode active material benefits in-depth understandings and research progress toward higher energy density electrochemical energy stor-age devices at all technology readiness levels.Due to various challenging issues,especially limited stability,nano-and micro-structured(NMS)electrodes undergo fast electrochemical performance degradation.The emerging NMS scaffold design is a pivotal aspect of many electrodes as it endows them with both robustness and electrochemical performance enhancement,even though it only occupies comple-mentary and facilitating components for the main mechanism.However,extensive efforts are urgently needed toward optimizing the stereoscopic geometrical design of NMS scaffolds to minimize the volume ratio and maximize their functionality to fulfill the ever-increasing dependency and desire for energy power source supplies.This review will aim at highlighting these NMS scaffold design strategies,summariz-ing their corresponding strengths and challenges,and thereby outlining the potential solutions to resolve these challenges,design principles,and key perspectives for future research in this field.Therefore,this review will be one of the earliest reviews from this viewpoint.

Ag-doped CNT/HAP nanohybrids in a PLLA bone scaffold show significant antibacterial activity

Bacterial infection is a major problem following bone implant surgery.Moreover,poly-l-lactic acid/carbon nanotube/hydroxyapatite(PLLA/CNT/HAP)bone scaffolds possess enhanced mechanical properties and show good bioactiv-ityregardingbonedefectregeneration.Inthisstudy,wesynthesizedsilver(Ag)-dopedCNT/HAP(CNT/Ag-HAP)nanohybrids via the partial replacing of calcium ions(Ca2+)in the HAP lattice with silver ions(Ag+)using an ion doping technique under hydrothermal conditions.Specifically,the doping process was induced using the special lattice structure of HAP and the abundant surface oxygenic functional groups of CNT,and involved the partial replacement of Ca2+in the HAP lattice by doped Ag+as well as the in situ synthesis of Ag-HAP nanoparticles on CNT in a hydrothermal environment.The result-ing CNT/Ag-HAP nanohybrids were then introduced into a PLLA matrix via laser-based powder bed fusion(PBF-LB)to fabricate PLLA/CNT/Ag-HAP scaffolds that showed sustained antibacterial activity.We then found that Ag+,which pos-sesses broad-spectrum antibacterial activity,endowed PLLA/CNT/Ag-HAP scaffolds with this activity,with an antibacterial effectiveness of 92.65%.This antibacterial effect is due to the powerful effect of Ag+against bacterial structure and genetic material,as well as the physical destruction of bacterial structures due to the sharp edge structure of CNT.In addition,the scaffold possessed enhanced mechanical properties,showing tensile and compressive strengths of 8.49 MPa and 19.72 MPa,respectively.Finally,the scaffold also exhibited good bioactivity and cytocompatibility,including the ability to form apatite layers and to promote the adhesion and proliferation of human osteoblast-like cells(MG63 cells).

Discussion on Scaffolding Teaching Mode of Traditional Chinese Medicine under the Background of Internet

This study was conducted to explore the construction of scaffolding teaching mode of Traditional Chinese Medicine under the background of"Internet+".The students of Grade 2018 majoring in traditional Chinese medicine were selected as the object,and some chapters of the textbook of traditional Chinese medicine were selected and taught by the traditional teaching mode while interspersing the scaffolding teaching mode,in order to help the implementation of the scaffolding teaching model.We adopted the methods of setting up situational scaffolding,question scaffolding and guide scaffolding to carry out relevant teaching contents.The scaffolding instruction model has a good degree of participation,and to a certain extent,it stimulates students'self-consciousness and enthusiasm,and improves their ability of analyzing and solving problems and their spirit of innovation.

Critical Reflection:Using Peer Scaffolding to Facilitate Students' Awareness of Collaboration

Traditional spoon-fed teaching in English classroom has exposed students to a trouble where they might lack enough collaborative experiences of language use in solving daily problems.In order to solve the problem,teachers are facing the challenge of prompting peer interaction within a scaffold.So the question of how to improve students’awareness of collaboration in English classes has become the main focus of this article.It will try to discuss about the concept of peer scaffolding while at the same time,reflect on a detailed lesson plan which uses it to raise students’awareness to cooperate in problem solving.

Effects of Peer-scaffolding on EFL Students in Completing a Collaborative Oral Task

This mini research explored effects of peer-scaffolding on EFL students through a collaborative oral task. In general,there are two research questions. The first one is: What kind of peer scaffolding behaviors can be reflected from the two participants? While the other is: How do these peer scaffolding behaviors affect or help EFL students to complete the collaborative oral task? From the research, 10 scaffolding behaviors were analyzed and classified into 5 aspects. Meanwhile, effects of peer-scaffolding can be investigated from 5 aspects mentioned above. In short, all the peer-scaffolding behaviors in this study play a positive role in helping two participants to complete the task.

Study on the Scaffolding Teaching of Three-dimensional Animation Foundation based on Modularization

In this paper, the teaching of course Three-dimensional Animation Foundation is designed mainly based on teaching content modularization and scaffolding teaching model. The modularized content design for Three-dimensional Animation Foundation is specifically expounded, and also the ideas for developing the scaffolding teaching model are analyzed. How to integrate the scaffolding teaching model into course teaching is introduced in details. Finally, new methods for guiding students to think independently in course teaching and improve students＇ self-awareness and self-learning ability are proposed.

Scaffolding Information of Learner’s Dictionaries for L2 Writing: A User Perspective

As a major resource and tool of language learning, learner’s dictionaries have provided sufficient information forL2 writing, which serves as a good guide of peer feedback. Hence, learner’s dictionaries are an indispensable partof scaffolding in the L2 writing feedback system. However, the effects of dictionary use in L2 writing have longbeen ignored either in L2 writing pedagogy or in learner lexicography. By applying the concept of “scaffolding” topeer feedback as the theoretical framework, this study first clarifies three distinct types of scaffolding informationpresented in current English learner’s dictionaries, and then makes an investigation into EFL learners’ perceptionand practical use of scaffolding information in their English writing. Results show that most EFL learners havepositive attitudes towards scaffolding information and its role in motivating effective feedback in English writing.But their practical use of such information is not satisfactory owing to their inadequate skills and knowledge ofdictionary use. This reflects a high demand of a dictionary use course in universities, which will help to raise EFLlearners’ dictionary use efficiency as well as improve English teachers’ lexicographical expertise in English writingpedagogy.

The Analysis of Scaffolding Instruction Application in Senior High School English Writing Teaching —— Based on Students of Zuoyun High School in Datong

This study aims to investigate the relationship between English Writing achievement and scaffolding instruction with 100 Students from Zuoyun high school as subjects in a quantitative method.Results show that:1)On the whole,high school students have good use of scaffolding in English writing.2)The application of scaffolding instruction in high school English writing teaching has a significant positive correlation with English writing performance.3)On the whole,there is a significant difference in the application of the scaffolds in English writing between high and low-score group students.

Application of Scaffolding Instructional Models to English Listening Comprehension

The paper tries to research Scaffolding Instructional Model in listening English teaching. There will be the theoretical research of Scaffolding Instructional Model and then the findings confirmed by the questionnaire. The subjects in the experiment is a group of 80 students randomly selected from the Grade Three at a senior high school in Yili. The questionnaire I presents that the students are on the close level of English listening. They are divided into Experimental Group and Control Group. The Scaffolding Instructional Model will be used on the Experimental Group and Control Group will take the traditional teaching method. After four weeks two groups will attend the listening post-test and questionnaire II. According to the analysis of experimental data, the Experimental Group would get better listening comprehension grades than the Control Group.

Customized scaffolds for large bone defects using 3D‑printed modular blocks from 2D‑medical images

Additive manufacturing(AM)has revolutionized the design and manufacturing of patient-specific,three-dimensional(3D),complex porous structures known as scaffolds for tissue engineering applications.The use of advanced image acquisition techniques,image processing,and computer-aided design methods has enabled the precise design and additive manufacturing of anatomically correct and patient-specific implants and scaffolds.However,these sophisticated techniques can be timeconsuming,labor-intensive,and expensive.Moreover,the necessary imaging and manufacturing equipment may not be readily available when urgent treatment is needed for trauma patients.In this study,a novel design and AM methods are proposed for the development of modular and customizable scaffold blocks that can be adapted to fit the bone defect area of a patient.These modular scaffold blocks can be combined to quickly form any patient-specific scaffold directly from two-dimensional(2D)medical images when the surgeon lacks access to a 3D printer or cannot wait for lengthy 3D imaging,modeling,and 3D printing during surgery.The proposed method begins with developing a bone surface-modeling algorithm that reconstructs a model of the patient’s bone from 2D medical image measurements without the need for expensive 3D medical imaging or segmentation.This algorithm can generate both patient-specific and average bone models.Additionally,a biomimetic continuous path planning method is developed for the additive manufacturing of scaffolds,allowing porous scaffold blocks with the desired biomechanical properties to be manufactured directly from 2D data or images.The algorithms are implemented,and the designed scaffold blocks are 3D printed using an extrusion-based AM process.Guidelines and instructions are also provided to assist surgeons in assembling scaffold blocks for the self-repair of patient-specific large bone defects.

Application of Scaffolding in Combination with Other Teaching Strategies in Translation Lessons among Senior High School Students in China

This study measures the effectiveness of combining group discussions,pre-questionings,or both with scaffolding teaching strategies in translation lessons based on Angelelli's translation competence model.However,in practice,the feasibility of using the Angelelli’s scoring scale to measure translation competence requires further verification by other empirical studies.The results of this study are only for reference,in hope that future researchers may contribute to the improvement in this subject.

Biological scaffold as potential platforms for stem cells:Current development and applications in wound healing

Wound repair is a complex challenge for both clinical practitioners and researchers.Conventional approaches for wound repair have several limitations.Stem cell-based therapy has emerged as a novel strategy to address this issue,exhibiting significant potential for enhancing wound healing rates,improving wound quality,and promoting skin regeneration.However,the use of stem cells in skin regeneration presents several challenges.Recently,stem cells and biomaterials have been identified as crucial components of the wound-healing process.Combination therapy involving the development of biocompatible scaffolds,accompanying cells,multiple biological factors,and structures resembling the natural extracellular matrix(ECM)has gained considerable attention.Biological scaffolds encompass a range of biomaterials that serve as platforms for seeding stem cells,providing them with an environment conducive to growth,similar to that of the ECM.These scaffolds facilitate the delivery and application of stem cells for tissue regeneration and wound healing.This article provides a comprehensive review of the current developments and applications of biological scaffolds for stem cells in wound healing,emphasizing their capacity to facilitate stem cell adhesion,proliferation,differentiation,and paracrine functions.Additionally,we identify the pivotal characteristics of the scaffolds that contribute to enhanced cellular activity.

3D-printed Mg-1Ca/polycaprolactone composite scaffolds with promoted bone regeneration

In bone tissue engineering,polycaprolactone(PCL)is a promising material with good biocompatibility,but its poor degradation rate,mechanical strength,and osteogenic properties limit its application.In this study,we developed an Mg-1Ca/polycaprolactone(Mg-1Ca/PCL)composite scaffolds to overcome these limitations.We used a melt blending method to prepare Mg-1Ca/PCL composites with Mg-1Ca alloy powder mass ratios of 5,10,and 20 wt%.Porous scaffolds with controlled macro-and microstructure were printed using the fused deposition modeling method.We explored the mechanical strength,biocompatibility,osteogenesis performance,and molecular mechanism of the Mg-1Ca/PCL composites.The 5 and 10 wt%Mg-1Ca/PCL composites were found to have good biocompatibility.Moreover,they promoted the mechanical strength,proliferation,adhesion,and osteogenic differentiation of human bone marrow stem cells(hBMSCs)of pure PCL.In vitro degradation experiments revealed that the composite material stably released Mg_(2)+ions for a long period;it formed an apatite layer on the surface of the scaffold that facilitated cell adhesion and growth.Microcomputed tomography and histological analysis showed that both 5 and 10 wt%Mg-1Ca/PCL composite scaffolds promoted bone regeneration bone defects.Our results indicated that the Wnt/β-catenin pathway was involved in the osteogenic effect.Therefore,Mg-1Ca/PCL composite scaffolds are expected to be a promising bone regeneration material for clinical application.Statement of significance:Bone tissue engineering scaffolds have promising applications in the regeneration of critical-sized bone defects.However,there remain many limitations in the materials and manufacturing methods used to fabricate scaffolds.This study shows that the developed Ma-1Ca/PCL composites provides scaffolds with suitable degradation rates and enhanced boneformation capabilities.Furthermore,the fused deposition modeling method allows precise control of the macroscopic morphology and microscopic porosity of the scaffold.The obtained porous scaffolds can significantly promote the regeneration of bone defects.