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The influence of TiN addition on the new precipitation sequence and hardening effects of TiN modified Al-Mn-Sc alloy processed by LPBF was systematically studied in this work. The diffusion behavior of TiN particles results in obvious difference in the main alloying elements concentrations, altering the lattice constants of both primary and secondary L12-Al3(Ti,Sc,Zr) precipitates in the alloy matrix composite. After being subjected to peak-aging treatment, a novel precipitation sequence was observed in the sample containing 1.5 wt% TiN via generating a higher volume fraction of coherent L12-Al3Sc and semi-coherent rod-like Al6(Mn,Fe) precursors, corresponding to an alleviated internal strain as well. This new phenomenon has been demonstrated as a novel hardening mechanisms contributing to both microstructure refinement and mechanical property enhancement. As the results, the sample containing 1.5 wt% TiN exhibits an ultra-high yield strength of 651 ± 7 MPa and a compensate fracture elongation rate of 3.9 ± 0.3 %.

In this work, the various amount of Nb powder was mechanically mixed into the Cu–Al–Mn shape memory alloys (SMAs) to prepare quaternary SMAs by laser powder bed fusion (LPBF). Altered microstructure, transformation behaviour of alloys and its underlying mechanisms were analyzed. Corresponding shape memory effect (SME) was also studied. Result shows that Nb content has significant effect on the microstructure, phase transition temperatures (TTs) and SME. The microstructure of the alloy was refined by addition of appropriate Nb content. The formation of precipitates and massive grain boundaries after the addition of Nb caused a reduction of TTs and wide thermal hysteresis. Sample with 1 at%Nb containing fine and small volume fraction precipitate shows the best available strain.

Mechanical and corrosion behaviors perpendicular to build direction (XOY) and along build direction (XOZ) of UNS S31803 duplex stainless steel (DSS) fabricated by laser powder bed fusion (LPBF) were investigated. With the post-annealing, the steel exhibited a ferrite-austenite microstructure. For XOY plane, austenite displayed a primarily texture while ferrite kept preferred orientation, and mainly held a Nishiyama-Wassermann orientation relationship. However, for XOZ plane, austenite showed a mixed texture. The average size of ferrite grains was larger for XOZ plane than XOY. The austenite in XOY plane was mostly island morphology grains, while in XOZ plane, there were a large number of coarse columnar grains. A higher geometrically necessary dislocation density and proportion of low-angle grain boundaries on XOY plane were observed. The yield strength and ultimate tensile strength values perpendicular to build direction were higher than those along build direction. While the total elongation perpendicular to build direction was lower. Moreover, the XOY plane shows slightly better corrosion resistance than the XOZ.

In this paper, a novel design strategy for l-PBFed AlMnMgScZr/TiN composites with ultrahigh strength was proposed. TiN particles can not only function as ceramic reinforcement, but also decompose and reprecipitate to form a large density of L12-precipitates at a high melting temperature during l-PBF. Meanwhile, the primary L12-Al3X (X=Ti/Sc/Zr) phase promotes the columnar-to-equiaxed grain transition effect, creating a fine bi-modal grain structure in the as-built sample. A high volume fraction of L12 nanoparticles are additionally precipitated from Al matrix during post heat treatment. In this regard, effective grain refinement and precipitation hardening mechanism contribute to an excellent tensile performance with a combination of an ultimate tensile strength of 681±4 MPa, a yield strength of 677±4 MPa, and an elongation rate of 5.4 ± 1.2%. The yield strength of 677 MPa is particularly the highest among all previously reported l-PBFed Al matrix composites and Al alloys.

In this study, the Cu-11.85Al-3.88Mn-1.6Nb (wt.%) shape memory alloy with low cost and a highly functional response was manufactured by selective laser melting(SLM). The effects of energy inputs (123–185J/mm3) on their microstructure, mechanical, and shape memory properties were investigated. It was observed that all of the samples were composed of 18R and 2H martensite, and the nanosized (Cu, Mn)3Al3Nd4 phase was formed during selective laser melting(SLM). In addition, the good compressive fracture strength and strain were 1652Mpa, and 15.1% respectively. An excellent shape memory effect of 99.26% recovery ratio and 5.32% shape memory strain was obtained by SLM.

Benzothiadiazole (BTH) is a plant resistance inducer that effectively delays ripening and senescence in fruits. To understand its possible mechanism, transcriptomics and metabolomics analyses were performed on banana (Musa spp.) fruit treated with BTH after their inoculation with the fungal pathogen Colletotrichum musae. A total of 1,747 differentially expressed genes (DEGs) were identified, and 1,160 were up- and 587 downregulated between the BTH and control conditions. These DEGs were highly enriched in metabolic pathways related to disease resistance, such as phenylpropanoid biosynthesis, flavonoids, and starch and sucrose metabolism. A metabolome analysis identified 138 differentially accumulated metabolites (DAMs) of which 73 were upregulated and 65 downregulated between the BTH and control conditions. Flavonoids were significantly upregulated DAMs. Transcriptome and metabolome analyses showed that the lignin biosynthesis and flavonoid biosynthesis pathways played important roles in the disease resistance of banana fruit induced by BTH by upregulating the expression of PAL, 4CL, PER, CHS, FLS, and FL3H. Moreover, WRKY transcription factors (TFs) also played key roles in this process of resistance by mediating genes related to disease resistance, such as PR1, PR1c, TLPH, PTI5, and other genes. Our results suggested that the BTH treatment significantly changed the expression of transcripts and metabolites related to the hormone signaling, secondary metabolism, disease resistance, and key TFs, which induced the disease resistance and delayed the ripening process. The insights into these molecular mechanisms also provide potential targets for genetic or chemical approaches to further enhance fruit quality and resistance.

After hunting, predators tend to leave a large amount of carrion behind. It is widely reported that this resource is commonly used by various species in the ecosystem and is essential for the survival of scavengers, particularly in winter. Although recent studies are focused on mammals, little is known about how this works with facultative scavenger birds, which may lead to a serious underestimation of the key role that top predators such as the Amur tiger (Panthera tigris altaica) play in ecosystems. Here, we conducted a field feeding experiment to quantitatively evaluate the effects of Amur tiger on avian scavengers by simulating their predation residue. The results show that the Corvidae is the main bird species that consumes carrion, while woodpeckers and some insectivorous songbirds also benefit from the remains that Amur tiger leaves behind. We assumed that in winter, if the daily energy demand for the six main scavenger birds completely relied on the predation residues of Amur tiger separately, the prey remains of one Amur tiger could feed about 28 crows, 49 Azure-winged magpies, 61 Eurasian jays, 235 Eurasian nuthatches, 96 Great spotted woodpeckers, or 385 Willow tits. It means that the prey remains of top predators like Amur tiger may be an extremely important resource to avian scavengers and carrion could be a potential ecological indicator of Amur tiger keystone effect. This study provides experimental evidence from the field for the first time, and reveals the ecological mechanism of the role of keystone species of the Amur tiger, i.e., how to indirectly protect other animal groups in the forest ecosystem that have important ecological value for the biodiversity and the health of local forest vegetation through the protection of the Amur tiger.

As a smart material, Shape Memory Polymer (SMP) can perceive changes in the external environment in which it is located, and make corresponding instantaneous active responses to the changes. In this study, polyurethane polymer was synthesized with polycaprolactone (PCL) as the soft segment, 2,2-dihydroxymethyl propionic acid (DMPA) and diisocyanate as the hard segment. DMA is used to evaluate the shape memory performance of the polymer, and results indicate that the synthesized polymer has a wide transition temperature and exhibits excellent thermally induced double and triple shape memory. The polymer with a 1:1 M ratio of PCL and DMPA has a shape fixation rate of 80% and a recovery rate of 99%. After 3 cycles, the film can still quickly return to its original shape. The findings of the study show that the composite material has great application potential under high and low temperature environments drives.

Objectives: To determine if radiomics analysis based on preoperative computed tomography (CT) can predict early postoperative recurrence of giant cell tumor of bone (GCTB) in the spine. Methods: In a retrospective review, 62 patients with pathologically confirmed spinal GCTB from March 2008 to February 2018, with a minimum follow-up of 24 months, were identified. The mean follow-up was 73.7 months (range, 28.7–152.1 months). The clinical information including age, gender, lesion location, multi-vertebral involvement, and surgical methods, were obtained. CT images acquired before the operation were retrieved for radiomics analysis. For each case, the tumor regions of interest (ROI) was manually outlined, and a total of 107 radiomics features were extracted. The features were selected via the sequential selection process by using the support vector machine (SVM), then used to construct classification models with Gaussian kernels. The differentiation between recurrence and non-recurrence groups was evaluated by ROC analysis, using 10-fold cross-validation. Results: Of the 62 patients, 17 had recurrence with a recurrence rate of 27.4%. None of the clinical information was significantly different between the two groups. Patients receiving curettage had a higher recurrence rate (6/16 = 37.5%) compared to patients receiving TES (6/26 = 23.1%) or intralesional spondylectomy (5/20 = 25%). The final radiomics model was built using 10 selected features, which achieved an accuracy of 89% with AUC of 0.78. Conclusions: The radiomics model developed based on pre-operative CT can achieve a high accuracy to predict the recurrence of spinal GCTB. Patients who have a high risk of early recurrence should be treated more aggressively to minimize recurrence.

A significant limitation in the engineering of artificial small-diameter vascular scaffolds is that the number of endothelial cells (ECs) is not sufficient to generate a confluent coverage of the vascular scaffolds, so that the surfaces of vascular scaffolds form thrombus via platelet adhesion and aggregation. Thrombus decrease relies on three-dimensional (3D) scaffolds to mimic the natural extracellular matrix (ECM) as templates to regulate cell behavior and facilitate tissue maturation. Here, we developed 3D scaffolds consisting of silk fibroin (SF) nanofibers and homogeneous microspheres by electrospinning and microfluidics. The nanofibers with diameters ranging from 250 to 350 ​nm doped with microspheres (2–10 ​μm) formed bridge-shaped structures. ECs were seeded and maintained on the 3D microsphere-nanofiber scaffolds with a mean fiber diameter of 300 ​nm. A 10% higher ratio of cell proliferation on 3D microsphere-nanofiber SF scaffolds was noted as compared to that on microporous and sponge-like SF scaffolds with small surface network fabricated by freeze-drying. Moreover, the gene transcript levels including CD146, VE-C and PECAM-1 were better preserved on 3D microsphere-nanofiber SF scaffolds than those on freeze-dried scaffolds. Thus, the developed 3D microsphere-nanofiber structure may have a myriad of applications in vascular tissue engineering scaffolds and cardiovascular devices.