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Gradient structured (GS) materials have been widely studied due to their excellent balance between strength and ductility. Surface mechanical attrition treatment (SMAT) can achieve grain refinement on the surface of materials, thereby obtaining gradient layers significantly impact the mechanical properties of materials. However, this processing method inevitably introduces high roughness on the surface. It cannot be ignored for the smoothness of the sample surface in a tensile test. In the present study, GS pure copper was prepared by SMAT. After fully annealing this gradient material in a vacuum environment and allowing the grains to grow completely (retaining the roughness caused by SMAT processing), it was found that its tensile mechanical properties were similar to those of fully annealed coarse-grained copper before SMAT processing. This indicates that the surface roughness of the sample is not an important factor affecting the tensile mechanical properties of pure GS copper. This work provides a meaningful insight into understanding the tensile mechanical behavior of gradient materials with high surface roughness.

For most metallic materials, the surface mechanical attrition treatment (SMAT) resulted in a substantial increase in the yield strength, but accompanied by a certain decrease in the ductility. However, the regulating of the yield strength and ductility in the gradient-structured Cu–Al–Zn alloys by the SMAT and annealing was less studied systematically. In this study, the microstructural evolution and mechanical properties of gradient-structured Cu–Al–Zn alloys with different stacking fault energy (SFE) after annealing were systematically investigated. The tensile properties show that the SMAT Cu–Al–Zn alloys with low SFE after annealing at 320 °C for 20 min exhibits a superior combination of strength and ductility. The microstructure characterizes reveal that the density of dislocations is decreased in the SMAT Cu–Al–Zn alloys with low SFE after annealing, meanwhile the degree of accumulated dislocations on the deformed twins is also weakened and maintains deformation twins feature, which thus achieve a superior balance of yield strength and ductility. Further analysis demonstrates that the annealed SMAT Cu–Al–Zn alloy with low SFE still maintains an obvious HDI strengthening. Furthermore, the digital image correlation (DIC) results indicate that during tensile deformation, gradient-structured Cu–Al–Zn alloys with low SFE can form dispersed strain bands, which contributes to improved ductility. This study provides a feasible strategy for regulating the strength and ductility of gradient-structured copper alloys.

Abstract Background The biomechanical environment created by suture‐button fixation Latarjet is conducive to the healing and shaping of the transplanted coracoid, but its mechanism remains unclear. The latest research has found that the absence of stem cell chemokine (CXCL12) impeded bone regeneration in Sonic Hedgehog (SHH)‐deficient animals. However, whether the biomechanical environment affects SHH and CXCL12 function has not been studied. Methods Rat fracture models were constructed to simulate stress environments under non‐load‐bearing and load‐bearing conditions. The fracture healing and shaping, as well as the expression levels of SHH and CXCL12, were assessed through gross viewing, micro‐computed tomography (micro‐CT), and histochemical staining. Results Under flexible fixation, the relative bone volume (BV/TV) of rats exposed to the load‐bearing stress environment was significantly higher than that of rats under a non‐load‐bearing stress environment (p ≤ 0.05). Adverse bone shaping was not observed in rats subjected to flexible fixation. The levels of SHH and CXCL12 in load‐bearing rats exhibited significant elevation (p ≤ 0.05). Under a load‐bearing stress environment, no significant difference was observed in the BV/TV between the flexible fixation group and the rigid fixation group (p ≥ 0.05), but there was excessive hyperplasia of the fracture callus in the rigid fixation group. The levels of SHH and CXCL12 in rats subjected to rigid fixation were significantly elevated (p ≤ 0.05). Conclusions Flexible fixation and load‐bearing stress environment may contribute to bone healing and shaping by influencing the levels of SHH and CXCL12, suggested that this mechanism may be relevant to the healing and shaping of the transplanted coracoid after suture‐button fixation Latarjet.

Abstract Background Native cartilage has low capacity for regeneration because it has very few progenitor cells. Human umbilical cord blood‐derived mesenchymal stem cells (hUCB‐MSCs) and human umbilical cord‐derived MSCs (hUC‐MSCs) have been employed as promising sources of stem cells for cartilage injury repair. Reproduction of hyaline cartilage from MSCs remains a challenging endeavor. The paracrine factors secreted by chondrocytes possess the capability to induce chondrogenesis from MSCs. Methods The conditioned medium derived from chondrocytes was utilized to induce chondrogenic differentiation of hUCB‐MSCs and hUC‐MSCs. The expression levels of collagen type I alpha 1 chain (Col1a1), collagen type II alpha 1 chain (Col2a1), and SRY‐box transcription factor 9 (SOX9) were assessed through quantitative real‐time polymerase chain reaction (qRT‐PCR), Western blot (WB), and immunofluorescence (IF) assays. To elucidate the mechanism of differentiation, the concentration of transforming growth factor‐β1 (TGF‐β1) in the conditioned medium of chondrocytes was quantified using enzyme‐linked immunosorbent assay (ELISA). Meanwhile, the viability of cells was assessed using Cell Counting Kit‐8 (CCK‐8) assays. Results The expression levels of Col2a1 and SOX9 were found to be higher in induced hUC‐MSCs compared to those in induced hUCB‐MSCs. The conditioned medium of chondrocytes contained TGF‐β1. The CCK‐8 assays revealed that the proliferation rate of hUC‐MSCs was significantly higher compared to that of hUCB‐MSCs. Conclusions The chondrogenic potential and proliferation capacity of hUC‐MSCs surpass those of hUCB‐MSCs, thereby establishing hUC‐MSCs as a superior source of seed cells for cartilage tissue engineering.

The SAF2507 duplex stainless steel with the heterogeneous structure is produced through cold rolling (ε = 90%) and subsequent 1-min normalizing at 1273 K. Compared with the corresponding initial samples, the grain sizes of ferrite and austenite phases in the 90%-1273 sample are refined by 90%, which led to an increase in the number of grain or phase boundaries between the two phases. The yield strength (YS) of the 90%-1273 sample increased to 715 MPa from 541 MPa, while the uniform elongation of 24.8% is slightly smaller than that of the coarse-grained sample. The higher YS is mainly contributed by the strengthening of grain refinement and dislocation strengthening by incorporating geometrically necessary dislocations (GNDs). During tensile deformation, the accumulation of GNDs in the heterostructured sample continuously generates hetero-deformation-induced (HDI) stress. The HDI stress plays a positive role in the 90%-1273 sample showing an ultimate tensile strength of 939 MPa. Additionally, the amount of twin boundaries in the 90%-1273 sample rose from 4.5% to 35% during tensile deformation, which indicated that the twinning induced plasticity effect was helpful in retaining the ductility of the 90%-1273 sample. This work provides strategies for optimizing the mechanical properties of duplex stainless steels and contributes to understanding the essence of a superior combination of strength and ductility of heterostructured materials.

Permeability is a fundamental property of porous media that governs the ability of a pore network to facilitate fluid flow through its pore spaces. However, the permeability test results are highly influenced by the type of fluid used during the measurements. This study investigates the influence of different fluids on permeability, excluding fluid-solid interactions. Permeability measurements were conducted on 30 clay-free Fontainebleau sandstones and 30 clay-free Y sandstones using kerosene and N2, with Klinkenberg-corrected gas permeability determined for comparison. Scanning electron microscopy (SEM) was employed to examine the presence of liquid films and particle migration within pore throats. The results consistently showed lower oil permeability compared to gas permeability across all samples. SEM analysis revealed that liquid films on rock surfaces and particle migration within pore throats contributed to the permeability disparity between liquid and gas in Fontainebleau sandstone. In contrast, the lower hydrophilicity of Y sandstone resulted in a negligible presence of liquid films, with particle migration being the primary factor for reduced liquid permeability. Furthermore, a more pronounced slip effect was observed in Y sandstone compared to Fontainebleau sandstone, attributed to its finer pore throats. These findings underscore the critical roles of liquid films, particle migration, and pore throat characteristics in determining permeability and highlight the relationship between the slip factor and permeability in porous media.

Studying immiscible fluid displacement patterns can provide a better understanding of displacement processes within heterogeneous porous media, thereby helping improving oil recovery and optimizing geological CO2 sequestration. As the injection rate of water displacing oil increases and the displacement pattern transits from capillary fingering to viscous fingering, there is a broad crossover zone between the two that can adversely affect the oil displacement efficiency. While previous studies have utilized phase diagrams to investigate the influence of the viscosity ratio and wettability of the crossover zone, fewer have studied the impact of rock heterogeneity. In this study, we created pore network models with varying degrees of heterogeneity to simulate water flooding at different injection rates. Our model quantifies capillary and viscous fingering characteristics while investigating porous media heterogeneity's role in the crossover zone. Analysis of simulation results reveals that a higher characteristic front flow rate within the crossover zone leads to earlier breakthrough and reduced displacement efficiency. Increased heterogeneity in the porous media raises injection-site pressure, lowers water saturation, and elevates the characteristic front flow rate, thereby expanding the extent of crossover zone.

Requirements-to-code traceability link recovery (RC-TLR) can establish connections between requirements and target code artifacts, which is critical for the maintenance and evolution of large software systems. However, to the best of our knowledge, there is no existing experimental study focused on state-of-the-art (SOTA) methods for the RC-TLR problem, and there is also a lack of uniform benchmarks for evaluating new methods in the field. We developed a framework to identify SOTA methods using the Systematic Literature Review method and applied it to research in the RC-TLR field from 2018 to 2023. Through experiments replication on 13 datasets using 6 methods, we observed that for information retrieval-based methods, Close Relations between Target artifacts-based method (CRT), TraceAbility Recovery by Consensual biTerms (TAROT), and Fine-grained TLR (FTLR) performed well on COEST dataset, while Combining Part-Of-Speech with information-retrieval techniques (Conpos) and TAROT achieve promising results in large datasets. As concerns machine learning-based methods, Random Forest consistently exhibits strong performances on all datasets. We hope that this study can provide a comparative benchmark for performance evaluation in the RC-TLR field. The resource repository that we have established is expected to alleviate the workload of researchers in performance analysis, and promote progress of the field.

The design of gradient structure (GS) in metallic materials has been reported to obtain superior mechanical properties due to the interaction between the GS layer and the coarse-grained (CG) matrix. In this study, the mechanical response and microstructural evolution of the corresponding constituent layers of GS Cu-4.5Al alloy at different pre-strains were systematically investigated. The tensile results showed that the strain hardening capability of the GS layer was improved due to the constraint of the CG matrix. Meanwhile, an extra strengthening was observed at the interface between the GS layer and the CG matrix, resulting in a higher yield strength of the CG matrix constrained by the GS layer than that of the CG matrix without the GS layer constraints. Moreover, the extra strengthening at the interface of the GS and CG matrix was gradually reduced with increasing pre-strain due to the weakening of the interaction at the interface. Microstructural observations at the interface between the GS layer and the CG matrix revealed that more dislocations and twins were activated during pre-strain in the CG matrix having GS constraints than that of the CG matrix without GS constraints. The present work provides important insights on the interaction between constituent layers, in terms of the mechanical response and microstructure evolution.

Heterostructured materials consist of heterogeneous zones with dramatic variations in mechanical properties, and have attracted extensive attention due to their superior performance. Various heterostructured materials have been widely investigated in recent years. In the present study, a combination of two different types of heterogeneous structures, a surface bimodal structure and gradient structure, was designed using the traditional surface mechanical attrition treatment (SMAT) method in pure copper, and the mechanical properties and microstructural evolution of dual-heterostructure Cu were studied in depth. In total, 100 stainless steel balls with a diameter of 6 mm were utilized to impact the specimen surface at room temperature for a short period of time. In this work, the sample surface was divided into hard areas and soft areas, along with a roughly 90 μm gradient structure in the cross-sectional direction after 30 s of SMAT processing. After the partial SMAT processing, lasting 30 s, the strength increased to 158.0 MPa and a considerable ductility of 25.7% was sustained, which overcomes the strength–ductility trade-off. The loading–unloading–reloading (LUR) test was utilized to measure the HDI stress, and the result showed that the HDI stress of the partial SMAT sample was much higher than the annealed one, especially for the Cu-SMAT-30S specimen, the strength of which increased from 80.4 MPa to 153.8 MPa during the tensile test. An in situ digital image correlation (DIC) investigation demonstrated that the strain developed stably in the Cu-SMAT-10S specimen. Furthermore, electron backscatter diffraction (EBSD) was carried out to study the microstructural evolution after partial SMAT processing; the KAM value increased to 0.34 for the Cu-SMAT-10S specimen. This research provides insights for the effective combination of superior strength and good ductility in dual-heterostructure materials.

Water shortage seriously restricts the development of grassland agriculture in arid land and dramatically impacts alfalfa (Medicago sativa L.) quality content and hay yield. Reasonable irrigation methods have the potential to enhance the alfalfa quality content, hay yield, and thus quality yield. Whether partial root-zone drying subsurface drip irrigation (PRDSDI) improves the alfalfa quality yield, quality content, and hay yield is still unknown compared with conventional subsurface drip irrigation (CSDI). The effects of PRDSDI compared with that of CSDI and the interaction with irrigation volume (10 mm/week, 20 mm/week, and 30 mm/week) on the alfalfa quality yield were investigated in 2017–2018 and explained the change in quality yield with the alfalfa quality content and hay yield. Here, the results showed that PRDSDI did not increase the alfalfa quality yield in 2 years. PRDSDI significantly increased acid detergent fiber by 13.3% and 12.2% in 2018 with 10-mm and 20-mm irrigation volumes and neutral detergent fiber by 16.2%, 13.2%, and 12.6% in 2017 with 10-mm, 20-mm, and 30-mm irrigation volumes, respectively. PRDSDI significantly decreased the crude protein by 5.4% and 8.4% in 2018 with 10-mm and 20-mm irrigation volumes and relative feed value by 15.0% with 20-mm irrigation volume in 2017 and 9.8% with 10-mm irrigation volume in 2018, respectively. In addition, PRDSDI significantly increased the alfalfa average hay yield by 49.5% and 59.6% with 10-mm and 20-mm irrigation volumes in 2018, respectively. Our results provide a counterexample for PRDSDI to improve crop quality. Although there was no significant improvement in average quality yield by PRDSDI, the positive impact of average hay yield on quality yield outweighed the negative impact of quality content. Thus, it has the potential to improve quality yields. The novel findings regarding the effects of PRDSDI on quality yield are potentially favorable for the forage feed value in water-limited areas.

BackgroundMany studies have investigated the efficacy of acupuncture in treating depression, but the mechanism of acupuncture for depression is still controversial and there is a lack of meta-analysis of mechanisms. Consequently, we investigated acupuncture’s efficacy and mechanism of depression.MethodsWe searched the Cochrane Library, PubMed, EMBASE, Web of Science. The SYRCLE Risk of Bias Tool was used to assess bias risk. Meta-analysis was performed using Stata 15.0 for indicators of depression mechanisms, body weight and behavioral tests.ResultsA total of 22 studies with 497 animals with depressive-like behaviors were included. Meta-analysis showed that acupuncture significantly increased BDNF [SMD = 2.40, 95% CI (1.33, 3.46); I2 = 86.6%], 5-HT [SMD = 2.28, 95% CI (1.08, 3.47); I2 = 87.7%] compared to the control group (p

Traceability links between issues and commits (issue-commit links recovery (ILR)) play a significant role in software maintenance tasks by enhancing developers’ observability in practice. Recent advancements in large language models, particularly pre-trained models, have improved the effectiveness of automated ILR. However, these models’ large parameter sizes and extended training time pose challenges in large software projects. Besides, existing methods often overlook the association and distinction among artifacts, leading to the generation of erroneous links. To mitigate these problems, this paper proposes a novel link recovery method called MTLink. It utilizes multi-teacher knowledge distillation (MTKD) to compress the model and employs an adaptive multi-task strategy to reduce information loss and improve link accuracy. Experiments are conducted on four open-source projects. The results show that (i) MTLink outperforms state-of-the-art methods; (ii) The multi-teacher knowledge distillation maintains accuracy despite model size reduction; (iii) The adaptive multi-task tracing method effectively handles confusion caused by similar artifacts and balances each task. In conclusion, MTLink offers an efficient solution for ILR in software traceability. The code is available at https://zenodo.org/records/10321150.

Nanocrystallization can significantly improve the strength and hardness of metallic materials, but usually sacrifice ductility due to low work hardening capability. Heterostructured materials are an emerging class of materials with superior performances, because of their outstanding work hardening capability. In this work, a type of heterostructured material, a gradient structured Cu-Al alloy, was produced by surface mechanical attrition treatment (SMAT) at liquid nitrogen temperature. After SMAT processing, the yield strength was increased to more than 1.5 times, and the ductility remained almost unchanged. In conjunction with hetero-deformation induced (HDI) hardening, stacking fault energy is another important factor to increase the strain hardening in the system. Low stacking fault energy increased the density of stacking fault, and led to a finer spacing of nano twins (∼5.4 nm) and higher dislocation storage (8 × 1013 m−2) in the SMATed Cu-Al alloy at the intermediate strain stage. A significant up-turn of strain-hardening rate was also induced by low stacking fault energy.

SAF2507 duplex stainless steel (DSS) is often used as a structural component in ocean-going vessels and marine petroleum exploitation equipment, which require superior mechanical properties. In this study, we used cold rolling (CR) at room temperature with 55% or 80% deformation amounts and subsequent annealing at 1273 K in 1 min to prepare SAF2507 samples with a heterogeneous structure (HS) that was composed of ferrite and austenite phases with different grain sizes. Compared with the homogeneous structure samples, the yield strength of the HS samples increased, while the ductility did not decrease. The 55%-1273 and 80%-1273 samples exhibited the hetero-zone boundary-affected regions on both sides of the grain boundary, phase boundary, and twin boundary. This resulted in hetero-deformation-induced (HDI) strengthening and strain hardening of samples during tensile deformation, which improved the ultimate tensile strength of the HS samples while maintaining a good uniform elongation. In addition, the heterogeneous structure of DSS had better corrosion resistance than the initial sample of coarse grain (CG) structure; mainly because the HS samples had finer grains and more grain boundaries on the DSS surface than the CG structure, which is conducive to the formation of high-density passivation film on the surface of stainless steel. The current study provides a new method of material selection of some structural components with the demands of high strength and good ductility.

Recent studies have shown distinct soil microbial assembly patterns across taxonomic types, habitat types and regions, but little is known about which factors play a dominant role in soil microbial communities. To bridge this gap, we compared the differences in microbial diversity and community composition across two taxonomic types (prokaryotes and fungi), two habitat types (Artemisia and Poaceae) and three geographic regions in the arid ecosystem of northwest China. To determine the main driving factors shaping the prokaryotic and fungal community assembly, we carried out diverse analyses including null model, partial mantel test and variance partitioning analysis etc. The findings suggested that the processes of community assembly were more diverse among taxonomic categories in comparison to habitats or geographical regions. The predominant driving factor of soil microbial community assembly in arid ecosystem was biotic interactions between microorganisms, followed by environmental filtering and dispersal limitation. Network vertex, positive cohesion and negative cohesion showed the most significant correlations with prokaryotic and fungal diversity and community dissimilarity. Salinity was the major environmental variable structuring the prokaryotic community. Although prokaryotic and fungal communities were jointly regulated by the three factors, the effects of biotic interactions and environmental variables (both are deterministic processes) on the community structure of prokaryotes were stronger than that of fungi. The null model revealed that prokaryotic community assembly was more deterministic, whereas fungal community assembly was structured by stochastic processes. Taken together, these findings unravel the predominant drivers governing microbial community assembly across taxonomic types, habitat types and geographic regions and highlight the impacts of biotic interactions on disentangling soil microbial assembly mechanisms.

Excessive selenium has gradually become a potential environmentally hazardous element for all organisms. Limited knowledge is available regarding the toxic mechanism of selenium in pepper, so the quantitative proteomics of phosphorylation was studied by Tandem Mass Tag approaches. A total of 4434 phosphorylation sites were identified on 2058 proteins, of which 3749 sites of 1919 proteins contained quantitative information. In the Se/mock (seedlings without Se treatment) comparison group, the number of upregulated phosphoproteins (658) was significantly higher than that of the downregulated ones (61). Systematic bioinformatics analysis, including protein annotation, functional classification, subcellular localization, and cluster analysis was performed. A total of 33 over-represented motifs were found in serine phosphorylation, and the most frequent motif was ‘sP’ (308 occurrences). According to KEGG enrichment analysis, the upregulated phosphorylated proteins (DPPs) were most strongly associated with the ’phenylpropanoid biosynthesis’ and ’nicotinate and nicotinamide metabolism’ pathways, while those that were downregulated were associated with the ’ABC transporters’ and ‘plant hormone signal transduction’ pathways. Our data can provide new insights for evaluating the response mechanism of plants to selenium pollution and improving their resistance to selenium.

Mesenchymal stem/stromal cells (MSCs) are promising cell sources for regenerative medicine and the treatment of autoimmune disorders. Comparing MSCs from different tissues at the single-cell level is fundamental for optimizing clinical applications. Here we analyzed single-cell RNA-seq data of MSCs from four tissues, namely umbilical cord, bone marrow, synovial tissue, and adipose tissue. We identified three major cell subpopulations, namely osteo-MSCs, chondro-MSCs, and adipo/myo-MSCs, across all MSC samples. MSCs from the umbilical cord exhibited the highest immunosuppression, potentially indicating it is the best immune modulator for autoimmune diseases. MSC subpopulations, with different subtypes and tissue sources, showed pronounced differences in differentiation potentials. After we compared the cell subpopulations and cell status pre-and-post chondrogenesis induction, osteogenesis induction, and adipogenesis induction, respectively, we found MSC subpopulations expanded and differentiated when their subtypes consist with induction directions, while the other subpopulations shrank. We identified the genes and transcription factors underlying each induction at the single-cell level and subpopulation level, providing better targets for improving induction efficiency.

The connective eccentricity index (CEI) of a hypergraph G is defined as ξce(G)=∑v∈V(G)dG(v)εG(v), where εG(v) and dG(v) denote the eccentricity and the degree of the vertex v, respectively. In this paper, we determine the maximal and minimal values of the connective eccentricity index among all k-uniform hypertrees on n vertices and characterize the corresponding extremal hypertrees. Finally, we establish some relationships between the connective eccentricity index and the eccentric connectivity index of hypergraphs.

Introduction: To assess the effect of baricitinib on patient-reported outcomes (PROs) in patients with moderately to severely active rheumatoid arthritis (RA) who had an inadequate response to methotrexate (MTX). Methods: This was a 52-week, randomized, double-blind, placebo controlled, phase III study in patients with RA who had an inadequate response to MTX. Patients ( n = 290) receiving stable background MTX were randomly assigned (1:1) to receive placebo or baricitinib 4 mg once daily with a primary endpoint at week 12. PROs assessed included Health Assessment Questionnaire-Disability Index (HAQ-DI), Patient’s Global Assessment of Disease Activity, patient’s assessment of pain, Functional Assessment of Chronic Illness Therapy-Fatigue (FACIT-F), European Quality of Life-5 Dimensions-5 Level index scores and visual analogue scale, and measures collected in electronic patient daily diaries: duration of morning joint stiffness, Worst Tiredness, and Worst Joint Pain. Treatment comparisons were made with logistic regression and analysis of covariance models for categorical and continuous variables, respectively. Results: Statistically significant ( p ⩽ 0.05) improvements in all PROs were observed in the baricitinib 4 mg group compared to placebo as early as week 1 to week 4; and were sustained to week 24. These improvements were maintained until week 52 for the baricitinib group. A significantly larger proportion of patients met or exceeded the minimum clinically important difference for HAQ-DI (⩾0.22) and FACIT-F (3.56) profiles in the baricitinib group. Conclusion: Baricitinib provided significant improvements in PROs compared to placebo to 52 weeks of treatment in patients with RA who had an inadequate response to MTX. Clinicaltrials.gov identifier: https://clinicaltrials.gov/ct2/show/NCT02265705 ; NCT02265705; RA-BALANCE. Registered 13 October 2014

A graph is a block graph if its blocks are all cliques. In this paper, we study the average eccentricity of block graphs from the perspective of block order sequences. An equivalence relation is established under the block order sequence and used to prove the lower and upper bounds of the eccentricity on block graphs. The result is that the lower and upper bounds of the average eccentricity on block graphs are 1 and 1n⌊34n2−12n⌋, respectively, where n is the order of the block graph. Finally, we devise a linear time algorithm to calculate the block order sequence.

Abstract Background The role of rabbit synovial fluid-derived mesenchymal stem cells (rbSF-MSCs) in cartilage defect repair remains undefined. This work evaluates the in vivo effects of rbSF-MSCs to repair knee articular cartilage defects in a rabbit model. Methods Cartilage defects were made in the patellar grooves of New Zealand white rabbits. The rbSF-MSCs were generated from the knee cavity by arthrocentesis. Passage 5 rbSF-MSCs were assayed by flow cytometry. The multipotency of rbSF-MSCs was confirmed after 3 weeks induction in vitro and the autologous rbSF-MSCs and predifferentiated rbSF-MSCs were injected into the synovial cavity. The intra-articular injection was performed once a week for 4 weeks. The animals were euthanized and the articular surfaces were subjected to macroscopic and histological evaluations at 8 and 12 weeks after the first intra-articular injection. Results Hyaline-like cartilage was detected in the defects treated with rbSF-MSCs, while fibrocartilage tissue formed in the defects treated with chondrocytes induced from rbSF-MSCs. Conclusions Our results suggest that autologous undifferentiated rbSF-MSCs are favorable to articular cartilage regeneration in treating cartilage defects.

In this study, two different types of heterogeneous structures were prepared by controlling different surface mechanical attrition treatment (SMAT) time (5 s, 10 s, 30 s, 60 s). The effect of heterogeneous Cu with bimodal grain size structure (BGSS) and gradient structure (GS) on heterogeneous deformation induced (HDI) stress and mechanical properties was investigated systematically. By combining surface morphology with microhardness distribution, it was found that the surface grains of the SMAT-ed Cu (5 s and 10 s) were partially refined to exhibit BGSS, while the surface grains of SMAT-ed Cu (30 s and 60 s) were sufficiently refined to form GS. The load-unload-reload (LUR) tests results showed that HDI stress for SMAT 60s Cu was much higher than that of the SMAT 10s Cu. Furthermore, microstructure characterizations revealed that SMAT-ed Cu with BGSS and GS suppressed strain localization, which resulted in high strength and reasonable ductility.

In this paper, a magnetically guided micromanipulation method is proposed to accurately create artistic patterns with magnetic microrobots in a liquid environment for tissue engineering. A magnetically guided device is developed depend on symmetrical combination of square permanent magnets and array layout of soft magnetic wires, which changed the space distribution of magnetic field of conventional permanent magnet and generated powerful magnetic flux density and high magnetic field gradient. Furthermore, the morphological structure of the magnetic microrobot is flexibly adjusted via precise control of the volumetric flow rates inside the microfluidic device and the magnetic nanoparticles are taken along to enable its controllability by rapid magnetic response. And then, the spatial posture of the magnetic microrobot is contactless controlled by the magnetically guided manipulator and it is released under the influence of surface tension and gravity. Subsequently, the artistic fashions of the magnetic microrobots are precisely distributed via the dot-matrix magnetic flux density of the magnetically guided device. Finally, the experimental results herein demonstrate the accuracy and diversity of the pattern structures in the water and the developed method will be providing a new way for personalized functional scaffold construction.

Tissue engineering is focusing on processing tissue micro-structures for a variety of applications in cell biology and the “bottom-up” construction of artificial tissue. Over the last decade, microfluidic devices have provided novel tools for producing alginate hydrogel microfibers with various morphologies, structures, and compositions for cell cultivation. Moreover, microfluidic spun alginate microfibers are long, thin, and flexible, and these features facilitate higher-order assemblies for fabricating macroscopic cellular structures. In this paper, we present an overview of the microfluidic spinning principle of alginate hydrogel microfibers and their application as micro-scaffolds or scaffolding elements for 3D assembly in tissue engineering.

Purpose: To evaluate bone preservation and esthetic recovery between the socket-shield technique (SST) with different labial bone plate thicknesses and the conventional immediate implant technique (CIIT). Materials and Methods: Patients who underwent immediate implant placement in the anterior region were divided into three groups: the SST with a thickwall phenotype (> 1 mm; SSTA group), the SST with a thin-wall phenotype (< 1 mm; SSTB group), and the CIIT with a thickwall phenotype (> 1 mm; CIIT group). Radiologic images and clinical photos were collected before surgery, immediately postoperatively, and 6 months postoperatively. The labial bone width, labial bone width change (BWC), labial bone volume change (BVC), pink esthetic score (PES), and complication rate were evaluated among the three groups. Statistical analysis was performed using SPSS software. Results: A total of 60 patients (n = 20/group) were enrolled in this 6-month retrospective study. The BWC in the SSTA group (0.22 to 0.30 mm) and the SSTB group (0.18 to 0.33 mm) was less than that in the CIIT group (0.61 to 0.80 mm; P < .004). The SSTA group and the SSTB group had a lower BVC (24.08 vs 21.14 vs 54.81, respectively; P = .004) and greater PES (11.75 vs 11.65 vs 10.65, respectively; P = .009) than the CIIT group. No complications occurred among these patients. Conclusions: With the limitations of this study, it can be concluded that the SST is a reliable method for preserving bone and achieving satisfactory esthetic outcomes. The labial bone plate phenotype associated with the SST has minimal impact on both clinical and radiologic outcomes. [ABSTRACT FROM AUTHOR]

Surface mechanical attrition treatment (SMAT) method has been widely acknowledged to obtain desired combination of strength and ductility in metals and alloys, and helpfully overcome the "trade-off" between the two mechanical properties. Within researches for more than 20-years, the favorable mechanical properties are related to the typical gradient structure (GS) in metals and alloys prepared by SMAT. In this overview, the principle and process parameters of SMAT are concisely presented. The strengthening mechanisms are interpreted by traditional dislocation-twin theory, hetero-deformation induced (HDI) theory and theory of shear band and strain delocalization. Besides, the strengthening mechanisms and methods to obtain excellent mechanical properties are discussed. Furthermore, both the latest progresses in design of GS materials prepared by SMAT and some other research interests are displayed. [ABSTRACT FROM AUTHOR]