This study developed an efficient and reliable system for inducing polyploidy in
Hayata, a top-grade medicinal orchid. The resulting tetraploid gave a significant enhancement on various agronomic ...traits, including dry weight, fresh weight, shoot length, root length, leaf width, the size of stoma, and number of chloroplasts per stoma. A reduction of the ratio of length to width was observed in stomata and leaves of the tetraploid, and consequently, an alteration of organ shape was found. The major bioactive compounds, total flavonoid and gastrodin, were determined by the aluminum chloride colorimetric method and ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS), respectively. The tetraploid produced significantly higher contents of total flavonoid and gastrodin in the leaf, the stem, and the whole plant when compared with the diploid. The resulting tetraploids in this study are proposed to be suitable raw materials in the pharmaceutical industry for enhancing productivity and reducing cost.
In this study, we propose an innovative method to add trace in situ TiC nanoparticles into 40Cr steel to manipulate its microstructure and mechanical properties. The trace TiC nanoparticle/40Cr ...steels fabricated using this method exhibited better room- and high-temperature properties than those exhibited by unreinforced 40Cr steel. The yield strength, tensile strength, fracture strain, and impact toughness of the 0.054 wt% TiC nanoparticle/40Cr steel were 1293 MPa, 1460 MPa, 10.4%, and 24.2 J/cm2, respectively, which increased by 19.7%, 30.4%, 15.6%, and 33.0% than 40Cr steel. The good combination of strength, ductility, and toughness after adding trace TiC nanoparticles to 40Cr steel was attributed to fine grain strengthening, thermal mismatch strengthening, and second phase strengthening. This research provides a new method for fabricating nanosized ceramic particle-reinforced steel that can be used to develop high-performance steel with high efficiency and low cost.
•TiC nanoparticles offered nucleation sites for γFe and αFe by low lattice misfits.•In situ trace TiC nanoparticles enabled microstructure refinement of 40Cr steel.•More and fine RA were obtained by adding trace TiC nanoparticles.•Excellent strength and toughness were yielded by adding trace TiC nanoparticles.
Forging and welding are common necessary procedures for AA6××× alloys, and recrystallization is an inevitable process. However, it is still difficult to realize the control of the recrystallization ...behavior, while realizing the strengthening of mechanical properties of the base metal and welded joint. In this study, we overcome this problem through 0.5 wt% TiC–TiB2 nanoparticles, and fully reveal the influence of the nanoparticles on the recrystallization behavior of the base metal and nugget zone of a friction-stir-welded (FSW)-ed joint from the perspectives of dislocation rearrangement and grain boundary motion. The strengthening mechanisms of the base metal and FSW-ed joint are clarified. The recrystallization driving force of the base metal and nugget zone was increased. Dislocations with a higher density rearranged and formed more grain boundaries in the nugget zone. Besides, nanoparticles distributed on the grain boundaries restrained the vanishing of low-angle grain boundaries. The nugget zone microstructures were refined from 3.1 to 2.3 μm, and the recrystallization ratio was increased from 7.2% to 10.4% at 800 rpm. The grains in the nugget zone were refined from 2.2 to 1.9 μm, and the recrystallization ratio was increased from 16.1% to 18.4% at 1200 rpm. The promoted recrystallization in the nugget zone accelerated the release of stress. Nanoparticles weakened the precipitate coarsening in the nugget zone. After strengthening, the ultimate tensile strength and plastic strain of the FSW-ed joint at 800 rpm were increased by 4.7% and 18.8%, respectively. This study provides new approaches for a systematic microstructure evolution control in FSW-ed 6061 Al alloys.
•Trace nanoparticles double the recrystallization driving force of base metal.•More dislocation tangles promoted recrystallization of nugget zone.•Nanoparticle also inhibited grain coarsening of nugget zone.•Precipitate coarsening in the nugget zone was weakened.•FSW-ed joint softening was alleviated and the mechanical properties were enhanced.
Background
The incidence of left ventricular thrombus (LVT) is 4% to 15% in patients with anterior acute ST‐segment elevation myocardial infarction (ant‐AMI) in the era of primary percutaneous ...coronary intervention (PPCI). And patients with LVT have higher in‐hospital mortality.
Hypothesis
There is a relationship between LVT formation and 1‐year major adverse cardio‐cerebrovascular events (MACCE) in patients with ant‐AMI treated by PPCI.
Methods
Our study population included 1488 consecutive patients with ant‐AMI. The primary endpoint was the incidence of MACCE within 1 year after AMI. The secondary endpoint was the thrombosis disappearance.
Results
A total of 106 (7.1%) patients were diagnosed with LVT and 1382 (92.9%) patients without LVT. Patients with LVT had a higher incidence of MACCE than in patients without LVT (21.7%vs10.3%; P < 0.001). Univariate analysis showed LVT was associated with an increase in MACCE risk (odds ratio OR = 2.40; 95% confidence interval CI 1.37‐4.21; P < 0.001). When examining MACCE components individually, LVT was only associated with the incidence of congestive heart failure (OR = 2.41; 95% CI 1.29‐4.58; P = 0.001). After adjustment for principal confounders, LVT remained an independent risk factor for MACCE (HR = 2.28; 95% CI 1.12‐6.38; P = 0.020). Other independent predictors include 24‐hour LVEF, creatine kinase peak value, and age. Further analysis found patients with LVT in international normalized ratio (INR) ≥ 2 group had lower MACCE risk and higher thrombus disappearance than in INR < 2 group (13.5%vs29.6%; P = 0.044; 90.4%vs74.1%; P = 0.029).
Conclusion
For patients with ant‐AMI treated by PPCI, LVT is an independent predictor of 1‐year MACCE events. Treatment with vitamin K antagonist in the therapeutic range (INR ≥ 2) has the potential to reduce MACCE risk and promote disappearance of thrombus.
Optimizing strength and toughness are always the key issues for cutter materials. Generally, increasing the strength of the material would sacrifice its toughness or vice versa. In this work, the ...TiB2–Ti(C,N)-(Ni + Mo) cermets with high strength and high toughness were fabricated in Mo–Ni–B4C-Ti-BN systems by reactive hot pressing. With the addition of Mo, the highest combustion temperature decreased and the matching degree between ceramic particles and Ni binder was improved, which lead to the decrease in the porosity of cermets and the refinement of ceramic particles. The fabricated TiB2–Ti(C,N)–Ni cermet with 2 wt.% Mo addition exhibited the simultaneously improved strength and toughness. The σUCS and KIC of the TiB2– Ti(C,N)-(Ni+2Mo) cermet were 3.24 GPa and 7.28 MPa·m1/2 respectively, which were increased by 11% and 20% compared with those of the cermet without Mo addition. The strengthening mechanisms of the cermets with Mo addition were attributed to the refinement of ceramic particles, the improved homogeneity in the microstructure and the simultaneously increase in the strength of interfacial bonding and the binder itself.
•TiB2–Ti(C,N)-(Ni + Mo) cermet is in situ synthesized in Mo–Ni–B4C-Ti-BN reaction system.•Crystallographic matching degrees between ceramic particles and binder are improved.•Porosity and ceramic particles size are significantly reduced by Mo addition.•TiB2–Ti(C,N)-(Ni+2Mo) cermet exhibits improved strength and toughness.•The σUCS and KIC of TiB2–Ti(C,N)-(Ni+2Mo) are 3.24 GPa and 7.28 MPa m1/2 respectively.
The application of Cu-graphite composites in the field of friction materials is limited by the poor wettability between Cu and graphite and weakened mechanical properties. In this work, in-situ TiC ...layers were generated by interfacial resistance sintering with direct current to manipulate the interfacial bonding of the composites and enhance their comprehensive properties. The Ti added to the composites would react with graphite at the interface to generate TiC layers and form strong Cu–TiC-graphite interfaces due to interfacial reactions. When the added Ti content is 6 wt%, the composite demonstrates the most excellent mechanical properties and tribological characteristics, i.e., yield strength (168 MPa) and wear rate (2.7 × 10−10 m2/N) are 93.1% higher and 29.7% lower than those of the Cu-graphite composite without Ti addition, respectively. The dense TiC layer induces the strengthening of the Cu matrix and serves as the reinforcing phase to optimize the interfacial bonding and stress transfer, which not only greatly enhances the mechanical properties of the composite but also enables the composite to take full advantage of the hard TiC and graphite phases to obtain stable friction coefficient and low wear rate. This work provides a simpler technique to prepare modified Cu-graphite composites with excellent performance and contributes to the in-depth understanding of the enhancement mechanism of hard ceramic layers on the mechanical and tribological properties of composites.
Sirtuin 1 (
) overexpression significantly inhibits lipid deposition during yak intramuscular preadipocyte (YIMA) differentiation; however, the regulatory mechanism remains unknown. We elucidated the ...role of
in YIMA differentiation using lentivirus-mediated downregulation technology and conducted mRNA-seq and ChIP-seq assays using H3K9ac antibodies after
overexpression in order to reveal
targets during YIMA adipogenesis. Gene Ontology (GO) and Kyoto Encyclopedia of Genes and Genomes (KEGG) analyses were performed in order to identify the functional annotation of common genes. In addition, a potential target of
was selected to verify its effects on the differentiation and proliferation of YIMAs.
interfered with lipid deposition and promoted YIMA differentiation. In total, 143,518 specific peaks were identified after
overexpression, where genes associated with downregulation peaks were enriched in transcription, gene expression, lipid-related processes, and classical lipid-related pathways. The H3K9ac signal in the whole genome promoter region (2 kb upstream and downstream of the transcription start site (TSS)) was weakened, and the peaks were distributed across all gene functional regions. Genes that lost signals in their TSS region or gene body region were enriched in both biological processes and pathways associated with lipogenesis. The ChIP-seq results revealed 714 common differential genes in mRNA-seq, which were enriched in "MAPK signaling", "lipid and atherosclerosis", "mTOR signaling", and "FoxO signaling" pathways. A total of 445 genes were downregulated in both their H3K9ac signals and mRNA expression, and one of their most significantly enriched pathways was FoxO signaling. Nine genes (
,
,
,
,
,
,
,
, and
) lost the H3K9ac signal in their TSS regions and had low mRNA expression, and three genes (
,
, and
) had low expression but lost their H3K9ac signal in the gene body region. The interference of
significantly inhibited fat deposition during preadipocyte differentiation and promoted cell proliferation by increasing S-phase cell numbers. The present study provides new insights into the molecular mechanism of intramuscular fat content deposition and the epigenetic role of
in adipocyte differentiation.
It is challenging to concurrently control the microstructure evolutions after undergoing casting, sheet forming and welding. This study successfully addressed this challenge via trace TiC–TiB2 ...nanoparticles in the amelioration of solidification-rolling-welding microstructural evolution. Nanoparticles refined the solidified microstructures and significantly increased the net driving force for recrystallization, promoting the precipitation of nanoscale Guinier–Preston zones and β'' phases. The coarsening of the fusion and heat-affected zones was also effectively suppressed. The yield strength (YS) and ultimate tensile strength (UTS) of the rolled plates were enhanced by 31.3% and 16.3%, respectively, without significantly sacrificing ductility. Additionally, the YS and UTS of the as-welded welding joints were enhanced by 30.2% and 7.8%, respectively. The amelioration mechanism of TiC–TiB2 throughout the microstructural evolution and strengthening process was systematically investigated. This study provides a typical model for the complete amelioration of microstructural evolution in aluminum alloys under multiple processing conditions.
•The nucleation of solidified phases is promoted, and their growth is hindered.•Recrystallization and formation of coherent nanoscale precipitates are promoted.•Coarsening of fusion zone and heat affected zone is suppressed.•Building better microstructure configuration for improved properties.
This paper presents investigations on a new column form, namely, concrete-filled fiber-reinforced polymer-steel wire reinforced thermoplastics pipe (FRP-SRTP) columns (CFFSCs) which consist of a SRTP ...tube with an outer FRP confinement system and concrete filled in the core area. A series of axial compression tests were performed on CFFSCs, and parameters including the number of FRP layers, the FRP fiber type and the clear spacing of the FRP rings were investigated. The test results demonstrate that the concrete-filled SRTP tube columns have an excellent ductility and the outer FRP confinement system provides efficient confinement to CFFSCs. The dilation behavior of the concrete in CFFSCs with polyethylene terephthalate FRP is different to that of the concrete in CFFSCs with carbon FRP. Four existing design-oriented models are adopted to generate the ultimate axial stresses and their corresponding strains of concrete in CFFSCs. By comparing the test results and the theoretical predictions, it is found that the existing models provides inaccurate predictions for CFFSCs. The new column form is particularly suitable as a form of standing support for underground mines, where a novel supporting system requires both a large deformation capacity and a good structural integrity.
A classical Lagrangian staggered‐grid hydrodynamic (SGH) method on triangular grids is prone to cell‐to‐cell oscillations. The causes of these oscillations can be divided into two categories. One is ...dissipation and the other is fluid deformation. For dissipation, when the kinematic energy stored on nodes are dissipated into internal energy in cells (shock wave is the most typical case), the dissipated energy may be unevenly assigned among cells, thus causes oscillations. This kind of oscillations can be controlled to a small level through a carefully designed viscous stress tensor or artificial heat flux, as studied widely in references. For fluid deformation, as the grid composed of straight lines cannot deform as flexibly as a continuous fluid, the volume of a grid cell would not accurately represent that of a fluid element, and this volume error will lead to oscillations too. In this article, we study in the SGH framework a matter‐flow method, whose design principle is representing the under‐grid bending motion of fluid elements by matter transport through grid edges. We first derive governing equations of the matter flow velocity defined at each edge of a grid, then derive formulas for the mass, energy, and momentum fluxes on the edge with the matter flow velocity. We test the matter‐flow method in largely deforming fluids problems on triangular meshes. It is shown that serious oscillations arise in the regular SGH simulations, while they are well controlled after implementing the matter‐flow method. In order to get a knowledge about the adaptability of the matter‐flow method, we also test it in shock problems that do not fall within its design goal. For this purpose, an artificial heat flow is introduced in the SGH scheme to play a major role in stabilizing the shock capture. The test results show that the matter‐flow method can help improve the shock simulations. The source code can be downloaded from the GitHub repository:
https://github.com/zhaoli0321/Matterflow.
The traditional Lagrangian staggered‐grid hydrodynamic (SGH) method on triangular grids easily yields cell‐to‐cell oscillations due to mesh stiffness. This work develops in the SGH framework a novel matter‐flow method that allows matter to be transported between grid elements to overcome mesh stiffness. Numerical experiments show that the proposed method can effectively control oscillations arising from the large deformation of fluids, and can also help stabilize the shock captures.
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