Hepatocellular carcinoma (HCC) is the most frequent subtype of primary liver cancer and one of the leading causes of cancer-related death worldwide. However, the molecular mechanisms underlying HCC ...pathogenesis have not been fully understood. Emerging evidences have recently suggested the crucial role of long noncoding RNAs (lncRNAs) in the tumorigenesis and progression of HCC. Various HCC-related lncRNAs have been shown to possess aberrant expression and participate in cancerous phenotypes (e.g. persistent proliferation, evading apoptosis, accelerated vessel formation and gain of invasive capability) through their binding with DNA, RNA or proteins, or encoding small peptides. Thus, a deeper understanding of lncRNA dysregulation would provide new insights into HCC pathogenesis and novel tools for the early diagnosis and treatment of HCC. In this review, we summarize the dysregulation of lncRNAs expression in HCC and their tumor suppressive or oncogenic roles during HCC tumorigenesis. Moreover, we discuss the diagnostic and therapeutic potentials of lncRNAs in HCC.
In this paper, using electron backscatter diffraction (EBSD) and transmission electron microscope (TEM) characterization, we systematically investigated the dynamic recrystallization (DRX) mechanism ...and its effects on the texture orientation and grain refinement of Ti6Al4V titanium alloy subjected to laser shock peening (LSP). The results indicated shear bands-induced DRX mechanism played a vital role in texture transition and grain refinement during LSP. Based on the observation, the DRX mechanism was determined as continuous dynamic recrystallization (CDRX). Due to the wide range of local misorientation of grains within shear bands, the new dynamic recrystallized grains exhibited preferred selection of 1−21−0 orientation, thereby resulting in the original 011−0 fiber component weakening. The deformation is mainly supported by basal slip and pyramidal <c+a> slip in α phase during LSP, activating massive non-basal dislocation for the subsequent CDRX process. The more nucleation sites available closer to the surface, as well as the increasing adiabatic temperature induced by ultra-high strain rate deformation there, contributed to the improved DRX, resulting in more intense grain refinement on the top surface.
•Continuous dynamic recrystallization occurred during laser shock peening.•The new dynamic recrystallized grains with a wider crystal crystallographic orientation nucleate from shear bands.•The dynamic recrystallization process was mainly supported by basal slip and pyramidal <c+a> slip.•The finer grains are formed on the surface by dynamic recrystallization.
Neurodegenerative diseases, a subset of age-driven diseases, have been known to exhibit increased oxidative stress. The resultant increase in reactive oxygen species (ROS) has long been viewed as a ...detrimental byproduct of many cellular processes. Despite this, therapeutic approaches using antioxidants were deemed unsuccessful in circumventing neurodegenerative diseases. In recent times, it is widely accepted that these toxic by-products could act as secondary messengers, such as hydrogen peroxide (H
O
), to drive important signaling pathways. Notably, mitochondria are considered one of the major producers of ROS, especially in the production of mitochondrial H
O
. As a secondary messenger, cellular H
O
can initiate redox signaling through oxidative post-translational modifications (oxPTMs) on the thiol group of the amino acid cysteine. With the current consensus that cellular ROS could drive important biological signaling pathways through redox signaling, researchers have started to investigate the role of cellular ROS in the pathogenesis of neurodegenerative diseases. Moreover, mitochondrial dysfunction has been linked to various neurodegenerative diseases, and recent studies have started to focus on the implications of mitochondrial ROS from dysfunctional mitochondria on the dysregulation of redox signaling. Henceforth, in this review, we will focus our attention on the redox signaling of mitochondrial ROS, particularly on mitochondrial H
O
, and its potential implications with neurodegenerative diseases.
Vibratory finishing is an existing processing technology in the manufacturing process of aircraft engine blades. Laser shock peening (LSP) is to be applied in the blades manufacturing, and it is ...inevitable to combine with vibratory finishing. Firstly, the compound process sequence was determined by residual stress and surface roughness test on the Ti-3.5Mo-6.5Al-1.5Zr-0.25Si titanium alloy in this work, and the best-performing sequence of the compound process was ascertained to be LSP + vibratory finishing. Secondly, the surface microstructure was characterized after different surface treatments. It can be found that nanoscale grains were formed in the surface layer after LSP treatment, and more homogeneous nanostructure and lower surface roughness were achieved after LSP + vibratory finishing. Lastly, the vibration fatigue was chosen to verify the feasibility of the compound process. The results showed that the fatigue strength improved from 438 MPa to 544 MPa after the compound process treatment compared with the specimens treated by vibratory finishing only.
•A compound process of LSP and vibratory finishing was proposed.•A surface nanostructure was produced in Ti alloy by the compound process treatment.•The fatigue strength was improved from 438 to 544 MPa after compound process treatment.
High-temperature fatigue performance of turbine blades (material: nickel-based alloy) is improved by a surface nanocrystallization technology. Surface nanocrystallization characterized by XRD, SEM ...and TEM, can be achieved by laser shock peening (LSP). Different microstructures are observed at the depths along the direction of propagation of the shock wave. A layer of isometric 30–500 nm nanocrystalline (1-μm-thick) is formed homogeneously at the surface of materials after LSP. With a heat treatment at 600 °C, the surface nanocrystals remain, while most of the residual compressive stresses are relaxed. The nanohardness of the deformed plastic layer (surface) is improved by a single laser shock impact, and an increase in the number of impacts improves the nanohardness amplitude. This nanohardness exhibits good stability against temperature, because of dislocation strengthening after thermal effect. The results of combined high-and-low cycle fatigue tests at 530 °C reveal that fatigue life of the turbine blades increased significantly by LSP, which are primarily associated with the effects such as surface nanocrystallization, high-density dislocation and residual compressive stress after thermal relaxation.
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•Surface nanocrystallization in GH4133B alloy can be achieved by LSP.•Surface nanocrystals showed a good thermal stability after heat treatment.•Fatigue life of the turbine blades with LSP increased dramatically.
Laser shock peening (LSP) is an innovative surface treatment technique, and can significantly improve the fatigue performance of metallic components. In this paper, the objective of this work was to ...improve the fatigue resistance of TC6 titanium alloy by laser shock peening. Firstly, the effects on the microstructure and mechanical properties with different LSP impacts were investigated, which were observed and measured by X-ray diffraction (XRD), transmission electron microscope (TEM), residual stress tester and microhardness tester. Specially, nanostructure was detected in the laser-peened surface layer with multiple LSP impacts. Whereafter, a better parameter was chosen to be applied on the standard vibration fatigue specimens. Via the high-cycle vibration fatigue tests, the high cycle fatigue limits of the specimens without and with LSP were obtained and compared. The fatigue results demonstrate that LSP can effectively improve the fatigue limit of TC6 titanium alloy. The strengthening mechanism was indicated by analyzing the effects on the microstructure and mechanical properties comprehensively.
Multilayer gradient TiN/Ti (MLG-TiN/Ti) and multilayer TiN/Ti (ML-TiN/Ti) coatings with different layer numbers were deposited on Ti6Al4V alloy by filtered cathodic vacuum arc technique (FCVA) to ...improve the erosion resistance of the substrates. Scan electron microscopy (SEM), energy dispersive spectrometer (EDS), X-ray diffraction (XRD) and nanoindentation were used to examine the microstructural and mechanical properties of the as-deposited coatings. The erosion resistance of these coatings was evaluated with home-made erosion tester. Though the two types of coatings showed similar grain structure, the finer grain sizes and higher hardness were obtained for MLG-TiN/Ti coatings. The structure parameters had a significant influence on erosion resistance. The coating MLG-4 with total thickness 12.09 μm exhibited the lowest erosion rate both among MLG-TiN/Ti and ML-TiN/Ti coatings. It contains two TiN layers, two Ti layers and three gradient layers and the thickness ratio of these three kinds of the layer is 9:1:1. The gradient layers, which can restrain the propagation of lateral cracks, formed in MLG-TiN/Ti coatings made the contribution to the great improvement of the erosion resistance of MLG-TiN/Ti comparing with ML-TiN/Ti coatings.
•The MLG-TiN/Ti coatings have finer grain sizes and higher hardness comparing with the ML-TiN/Ti coatings.•The coating MLG-4 reduces the erosion rate of ML-4 from 0.085 mg/g to 0.007 mg/g under the same erosion condition.•The MLG-TiN/Ti coatings outperformed the corresponding multilayer coatings, showing a better resistance to cracking.•The erosion mechanisms and erosion resistance improvement mechanism of multilayer gradient TiN/Ti coatings were discussed.
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•3D-printed Ni-superalloy single crystals face four major challenges (R.A.S.H.).•Designed a single-step treatment to meet all the RASH requirements.•Recovery to avoid ...recrystallization while preventing stray grain growth.•Optimized annealing duration homogenizes chemical and precipitates distribution.
Single-crystal Ni-based superalloys are currently the material of choice for turbine blade applications, especially with the emerging additive manufacturing (AM) that facilitates the manufacture/repair of these single crystals. This promising AM route, however, comes with a dilemma: in the fusion and heat affected zones after e-beam or laser induced melting, one needs a solutionizing annealing to relieve the residual stresses and homogenize the chemical/microstructure. The super-solvus solutionizing temperature is usually adopted from the protocol for the cast superalloys, which almost always causes recrystallization and stray grain growth, resulting in a polycrystalline microstructure and degrading the high-temperature mechanical performance. Here we demonstrate a custom-designed post-printing heat treatment to replace the conventional super-solvus one. The recovery and relatively low temperature diminish the driving force for recrystallization and the movement of stray grain boundaries, without suffocating the chemical/microstructural homogenization thanks to the narrow dendrite width and short element segregation distance. The optimal duration of the heat treatment is proposed to achieve atomic-diffusion mediated chemical homogenization while limiting γ′-particle coarsening in the interdendritic regions. Our strategy makes it practically feasible to resolve several bottleneck problems with one processing/treatment, removing a seemingly formidable obstacle to effective additive manufacturing of superalloy single crystal products.
A desirable microenvironment is essential for wound healing, in which an ideal moisture content is one of the most important factors. The fundamental function and requirement for wound dressings is ...to keep the wound at an optimal moisture. Here, we prepared serial polyurethane (PU) membrane dressings with graded water vapor transmission rates (WVTRs), and the optimal WVTR of the dressing for wound healing was identified by both in vitro and in vivo studies. It was found that the dressing with a WVTR of 2028.3 ± 237.8 g/m(2)·24 h was able to maintain an optimal moisture content for the proliferation and regular function of epidermal cells and fibroblasts in a three-dimensional culture model. Moreover, the dressing with this optimal WTVR was found to be able to promote wound healing in a mouse skin wound model. Our finds may be helpful in the design of wound dressing for wound regeneration in the future.
Laser shock peening (LSP) is an effective surface treatment for improving fatigue resistance of metallic materials, in which high-amplitude beneficial residual stresses and structure changes can be ...produced. In aero-engines, the compressor blade made of TC11 titanium alloy was prone to result in high cycle fatigue (HCF) failure. The aim of this paper was to utilize LSP with befitting parameters to improve the HCF performance of TC11 titanium alloy. Firstly, the microstructure and mechanical properties of TC11 titanium alloy with different LSP impacts were observed and measured via transmission electron microscope (TEM), residual stress tester and microhardness tester. High-density dislocations and nanostructure were observed in the surface layer. High-amplitude compressive residual stresses were induced and microhardness was remarkably improved. According to the effects, a set of LSP parameters with three LSP impacts was confirmed and applied on standard vibration specimens. Vibration fatigue tests were conducted to validate the strengthening effect on HCF strength. The fracture mechanism was analyzed by fracture analysis. The strengthening mechanism of LSP was indicated by establishing the relationship between fatigue characteristics and effects on residual stress and microstructural changes.
•High-density dislocations and nanostructure are generated after LSP processing.•With LSP impacts increased, nano-grains get smaller and more uniform.•The fatigue strength of TC11 titanium alloy is improved from 483.2MPa to 593.6MPa.•The strengthening mechanism was indicated by LSP effects for fatigue behavior.
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