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The effect of nano-Y 2 O 3 addition on tensile properties and creep behavior of Ti–45Al–6Nb-2.5V alloy prepared by induction skull melting (ISM) has been studied in this paper. The results reveal that 0.15 at% Y 2 O 3 increases both ultimate tensile strength and elongation of the alloy, as 666 MPa and 0.56% at room temperature, 747 MPa and 14.1% at 800 °C, 597 MPa and 22.5% at 900 °C. And the alloy with nano-Y 2 O 3 addition displays a better creep resistance and longer creep life at 800 °C. Additionally, the fracture feature shows that the main failure mechanism of TiAl alloy at 800 °C during creep is initiation, growth and coalescence of voids and cracks in grain boundary. Particularly, Y 2 O 3 could impede dislocation movement and defer initiation and propagation of cracks to improve creep resistance. • The TiAl alloy with nano-Y 2 O 3 addition exhibited the desired high temperature tensile strength. • The addition of nano-Y 2 O 3 improved the creep resistance of TiAl alloy. • The effect of nano-Y 2 O 3 addition on the creep failure mechanism of TiAl alloy was concluded. [ABSTRACT FROM AUTHOR]

Ti6Al4V–Ti43Al9V laminate composites were successfully fabricated by hot-pack rolling using as-forged Ti43Al9V alloy and as-rolled Ti6Al4V alloy. The microstructure evolution of composites was investigated by electron probe microanalysis (EPMA) equipped with energy dispersive X-ray spectrometry (EDS) and the electron back scattered diffraction (EBSD). In order to better control the properties of laminate composites, two models are established for better control the thickness and phase formation of interfacial region, respectively. The mechanical properties of composites show a negative correlation with rolling temperature. The composite fabricated at 1125 °C exhibits the highest tensile strength 805 MPa and fracture toughness 49.2 MPa•m1/2 which are much higher than Ti43Al9V alloy and other Ti–Al based laminate composites. The fracture features reveal that the increase of tensile strength is attributed to high density of dislocations and sub-structures stored in TiAl alloy and the crack propagation features show that the enhancement of toughness is associated with the aggravation of misorientation of α 2 phase and the increase of the amount of γ/B2 boundaries. [ABSTRACT FROM AUTHOR]

Ti6Al4V (wt.%)-Ti43Al9V0·3Y (at.%) laminated composites were fabricated from as-forged TiAl and commercial Ti6Al4V sheet by hot-pack rolling, and the microstructure of composites were investigated. The results showed that the target laminated composites were achieved by reaction and diffusion bonding. A defect free interfacial region was observed indicating that The Kirkendall effect was successfully avoided by substituting Al metal foils with Ti43Al9V alloy sheets. The microstructure, from the Ti6Al4V side to the Ti43Al9V side, had four different microstructure regions which are α+β, α 2 , α 2 +γ+B2 and B2+γ, respectively. The tensile properties and fracture toughness of composites were examined. It was noteworthy that the composites not only retained high tensile properties in both room temperature and 700 °C, but also possessed high fracture toughness. It was also proved that the unique mix-phase interfacial region obtained by hot-pack rolling has a great contribution to the improvement of the properties of composites and strengthening-toughening mechanism were clarified profoundly. • The Ti6Al4V – Ti43Al9V laminated composites are successfully fabricated by hot-pack rolling. • The formation of interfacial region are controlled by atomic diffusion and interfacial reaction barriers. • The strength – fracture toughness balance of composites are achieved. • The mix-phase and gradient interfacial region makes a great contribution to improve the properties of composites. [ABSTRACT FROM AUTHOR]

Effects of TiB2 addition on Microstructure and Fluidity of Ti–48Al–2Cr–2Nb + x TiB 2 (x = 0.18, 0.36, 0.54, 0.72, 0.9, 1.8 wt%) alloys fabricated by vacuum non-consumable tungsten arc melting were investigated. Results showed that with adequate TiB 2 addition (0.72% TiB 2 and more), the as-cast microstructure transformed from coarse columnar grains to fine equiaxed grains, and the grain size was reduced from 800 μm to 200 μm. The morphology of borides transformed from flake to block and needlelike, resulted from the dissolution and re-precipitation of original TiB 2 powders. The fluidity of TiAl alloy was improved by the addition of TiB 2 , and the T4822–0.72TiB 2 alloy showed the largest filling length of 266.5 mm, 17.4% higher than that of the matrix alloy. The enhancement of fluidity and the cessation mechanism of melt flow for the TiB 2 -containing TiAl alloy were analyzed and discussed in light of the microstructure evolution, borides and solidification characterization. • Columnar grains transformed to equiaxed grains with 0.54 wt% TiB 2. • Grain size was refined from 800 μm to 200 μm with TiB 2 addition. • 0.72 wt% TiB 2 promoted the increase of fluidity by 17.4%. [ABSTRACT FROM AUTHOR]

High temperature titanium alloy/Ti-43Al-9V metal-intermetallic laminate composite was successfully fabricated by hot-pack rolling. The titanium alloy exhibits a lamellar structure and the TiAl alloy consists of B2 phase and elongated γ phase. Due to the low rolling and annealing temperature, the TiAl alloy shows a low extent of dynamic recrystallization (69.3%) and a high dislocations density (17%). The composite shows an excellent combination of the enhanced tensile strength and fracture toughness. The tensile strength of composite at 25 °C and 700 °C are 845 MPa and 730 MPa respectively. The fracture toughness of composite are 29.4 MPa∙m1/2 and 26.6 MPa∙m1/2 in arrester orientation and divider orientation respectively, which are much higher than monolithic Ti-43Al-9V alloy. The strengthening of composite is mainly attributed to high density dislocations and sub-structures stored in composite and the toughening mechanisms of composite are crack deflection, secondary cracks and crack tip convolution. • The Ti-TiAl laminate composite is successfully fabricated by hot-pack rolling. • High dislocations density and low extent of DRX are found in TiAl alloy. • The composite shows high tensile strength at 25 °C and 700 °C. • The fracture toughness of composite is much improved by laminate structure. [ABSTRACT FROM AUTHOR]

Limited by the composition, the service temperature of high-temperature titanium alloys have been restricted to 600 °C for many years. In this study, a self-designed Ti–6Al–3Sn–10Zr-(Mo, Nb, W, Si) near-α titanium alloy that can be used at 650–700 °C was fabricated by vacuum arc remelting (name as DsTi700). Isothermal compression tests were performed at 975–1100 °C and in the strain rate range of 0.01–1 s−1. The results indicate that the flow behaviors of DsTi700 alloy under high strain rate are different from that of some traditional near-α titanium alloys and the peak stress values are generally higher than those of some common near-α titanium alloys at the same/similar deformation conditions. The deformation activation energy Q in β phase field is 240.2 kJ/mol. Moreover, the processing map were developed to determine the optimal processing window. Finally, DsTi700 alloy pancake with basket-weave microstructure was successfully prepared by multi-pass hot-forging. Tensile tests exhibit that the elongation of DsTi700 alloy at room temperature is nearly 13%, the UTS exceeds 600 MPa at 650 °C, which is almost equal to the UTS of some traditional near-α titanium alloys at 600 °C. Moreover, the UTS and elongation of DsTi700 pancake are 511 MPa and 24.1% at 700 °C. • Hot deformation behavior of a novel near-α titanium alloy designed for the temperature of 650–700 °C were investigated. • The high peak stress can be attributed to abundant alloying elements including 10 wt% Zr and silicides in the matrix. • The processing map were developed successfully and theoptimal deformation conditions were determined. • The alloy pancake with improved tensile properties was successfully prepared by multi-pass hot-forging. [ABSTRACT FROM AUTHOR]

It is shown that a uniform and refined fully lamellar microstructure can be generated by tempering the quenched samples in the single α region of as-forged Ti–43Al–9V–Y alloy. The refining effect was mainly connected with the quenched microstructures especially for their substructure, grain size and the residual β particles after the quenching. A series of β-decomposed products: martensite plate, massive α and coarsened α lath with increasing grain size were produced due to the decreasing cooling rate during the wedge-shaped sample quenched into iced brine. In addition, the decomposition of β directly to γ has also been observed during the quenching with different cooling rate. The lamellar colony size can be controlled in the range of 25–50 μm after tempering. • Uniform and refined fully lamellar structure can be obtained by quenching and tempering. • The β-decomposed product varies from martensitic α plate, massive α to coarsened α lath with decreasing quenching rate. • The lamellar colony size after tempering is mainly connected with the quenched microstructures. [ABSTRACT FROM AUTHOR]

• A fluoride-containing anodic oxide layer with oriented porous structure on Ti-50Al was fabricated by anodizing. • The porous structure can be controlled accurately by optimizing anodic oxidation parameters. • Oriented porous anodic oxide layers indicated outstanding oxidation resistance with little or even no spallation at 800 °C. • Anti-oxidation mechanism of oriented porous anodic oxide layer was analyzed in detail. A fluoride-containing anodic oxide layer with oriented porous structure coated Ti-50Al intermetallic can be fabricated by anodizing in sulfuric acid (H 2 SO 4) solution containing a small quantity of hydrofluoric acid (HF). X-ray photoelectron spectroscopy (XPS) analysis reveals that the porous anodic oxide layer consists mainly of TiO 2 , Al 2 O 3 , titanium fluoride and aluminum fluoride. Cyclic oxidation tests indicate that all Ti-50Al samples anodized in fluorine-containing electrolyte exhibit outstanding oxidation resistance with little or even no scale spallation at 800 °C. The improvement of oxidation resistance is mainly attributed to the fluorine effect and the oriented porous structure of anodic oxide layer. [ABSTRACT FROM AUTHOR]

In recent years, electroconductive hydrogels (ECHs) have shown great potential in promoting nerve regeneration and motor function recovery following diabetic peripheral nerve injury (PNI), attributed to their similar electrical and mechanical characteristics to innate nervous tissue. It is well-established that PNI causes motor deficits and pain, especially in diabetics. Current evidence suggests that ropivacaine (ROP) encapsulated in poly lactic-co-glycolic acid (PLGA) microspheres (MSs) yield a sustained analgesic effect. In this study, an ECH electroconductive network loaded with MS/ROP (ECH-MS/ROP) was designed as a promising therapeutic approach for diabetic PNI to exert lasting analgesia and functional recovery. This dual delivery system allowed ROP's slow and sequential release, achieving sustained analgesia as demonstrated by our in vivo experiments. Meanwhile, this system was designed like a lamellar dressing, with desirable adhesive and self-curling properties, convenient for treating injured nerve tissues via automatically wrapping tube-like structures, facilitating the process of implantation. Our in vitro assays verified that ECH-MS/ROP was able to enhance the adhesion and motility of Schwann cells. Besides, both in vitro and in vivo studies substantiated that ECH-MS/ROP stimulated myelinated axon regeneration through the MEK/ERK signaling pathway, thereby improving muscular denervation atrophy and facilitating functional recovery. Therefore, this study suggests that the ECH-MS/ROP dressing provides a promising strategy for treating diabetic PNI to facilitate nerve regeneration, functional recovery and pain relief., Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (© 2023 The Authors.)

Melatonin is crucial for protecting neural stem cells (NSCs) from reactive oxygen species (ROS). However, the mechanism underlying these processes is unclear. In this study, we first investigated the significantly upregulated lncRNA MEG3 biomarker in the H 2 O 2 -induced NSCs and control groups. Melatonin inhibited the expression of MEG3 by methylation. MEG3 overexpression reversed the positive effects of melatonin on NSCs against H 2 O 2 . Furthermore, MEG3 reduced the expression levels of its targeted miRNA-27a-3p, which could be considered a neuroprotective effect. In addition, the elevated miRNA-27a-3p decreased JNK phosphorylation by targeting MAP2K4. Overexpression of MAP2K4 suppressed the neuroprotective effects of miRNA-27a-3p. Therefore, melatonin appeared to protect NSCs from H 2 O 2 -induced ROS by modification of the MEG3/miRNA-27a-3p/MAP2K4 axis., (Copyright © 2020 IBRO. Published by Elsevier Ltd. All rights reserved.)

Emerging evidence indicates that microRNAs play a pivotal role in neural remodeling after spinal cord injury (SCI). This study aimed to investigate the mechanisms of miR-135a-5p in regulating the functional recovery of SCI by impacting its target genes and downstream signaling. The gene transfection assay and luciferase reporter assay confirmed the target relationship between miR-135a-5p and its target genes (specificity protein 1 [SP1] and Rho-associated kinase [ROCK]1/2). By establishing the H 2 O 2 -induced injury model, miR-135a-5p transfection was found to inhibit the apoptosis of PC12 cells by downregulating the SP1 gene, which subsequently induced downregulation of pro-apoptotic proteins (Bax, cleaved caspase-3) and upregulation of anti-apoptotic protein Bcl-2. By measuring the neurite lengths of PC12 cells, miR-135a-5p transfection was found to promote axon outgrowth by downregulating the ROCK1/2 gene, which subsequently caused upregulation of phosphate protein kinase B (AKT) and phosphate glycogen synthase kinase 3β (GSK3β). Use of the rat SCI models showed that miR-135a-5p could increase the Basso, Beattie, and Bresnahan (BBB) scores, indicating neurological function recovery. In conclusion, the miR-135a-5p-SP1-Bax/Bcl-2/caspase-3 and miR-135a-5p-ROCK-AKT/GSK3β axes are involved in functional recovery of SCI by regulating neural apoptosis and axon regeneration, respectively, and thus can be promising effective therapeutic strategies in SCI., (© 2020 The Authors.)

Objectives: Enhanced recovery after surgery (ERAS) principle and minimally invasive surgery allow patients to recover faster and better postoperatively. Due to a paucity of their integration, this retrospective study aims to assess clinical outcomes of ERAS pathway in microendoscopy-assisted minimally invasive transforaminal lumbar interbody fusion (MIS-TLIF)., Patients and Methods: A total of 72 consecutive cases were enrolled. According to their inclusion order, the former 21 cases received microendoscopy-assisted MIS-TLIF without any ERAS approach (control group), while the latter 51 participants underwent the same surgery with ERAS protocol (observation group). Perioperative parameters, including operative duration, intraoperative estimated blood loss (EBL), length of stay, postoperative analgesic usage and ambulatory time, were recorded. Visual analogue scale (VAS, back and leg), Barthel index were obtained before and at three days, one month, six months postoperatively. Modified MacNab criteria and Bridwell grading were used to assess surgical outcome and interbody fusion at one week and two years after surgery, respectively., Results: Observation group had statistically improved perioperative parameters (operative duration, intraoperative EBL, length of stay, postoperative analgesic usage and ambulatory time) in comparison with control group. Remarkable decreases in VAS (back and leg) were observed continuously at three days, one month and six months post-surgery in both groups when compared with scores prior to the surgery. More significant improvement of VAS (back and leg) was found in observation group at both three days and one month postoperatively. Regarding Barthel index, despite its transient decrease at three days after surgery in control group, it showed statistical increase at postoperative one month when compared with preoperative values in both groups; moreover, its inter-groups comparison revealed much more improvement in patients receiving ERAS recommendations; while at final follow-up, it continued further increase in either group. Marginally higher proportion of patients in observation group showed perfect or good clinical outcome, as well as solid interbody fusion., Conclusions: ERAS pathway in microendoscopy-assisted MIS-TLIF has advantages of decreased operative time, reduced intraoperative haemorrhage, increased initial back pain relief, decreased length of stay, lowered analgesic usage and earlier daily activity recovery and thus, benefit postoperative rehabilitation further., (Copyright © 2020 Elsevier B.V. All rights reserved.)