The microstructural evolution and mechanical properties of S31042 heat-resistant steel after crept at 923K were systematically investigated. Results show that secondary NbCrN and M23C6 are the ...predominant precipitates during creep. Long-term creep results in the precipitation of a small amount of σ phase and a few Cr3Ni2SiX. Secondary NbCrN is the most important strengthening precipitate of S31042 steel. At least 75% of the precipitation hardening results from secondary NbCrN. Furthermore, secondary NbCrN is the main factor to affect the variation of hardness of S31042 steel during creep. The dramatic degradation of plasticity is mainly caused by the precipitation of M23C6 at the grain boundaries. Chain-like M23C6, cuboids M23C6 and undissolved NbCrN are also harmful to the creep plasticity of S31042 steel.
Stainless steel core panel is a novel structure for fast modular building, but its brazing foils are susceptible to defects due to the difficulty of precisely controlling the brazing process. An ...automated, nondestructive testing technique is highly desirable for quick inspection of the brazing defects buried in the stainless-steel core panel. In this paper, pulsed eddy current testing (PECT) was employed to inspect local incomplete brazing defects. Finite element simulation and experiment verification were conducted to investigate the feasibility and effectiveness of the proposed method. The peak value of the PECT signal was found to be sensitive to the presence of the defect. With the aid of an industrial robotic arm, line and two-dimensional scans were performed of the PECT probe above the panel specimen. The prefabricated incomplete brazing foil was successfully imaged as a notched ring, whose opening coincides with the physical length of the missing brazing. The proposed method shows potential to serve as an effective tool for in-line or off-line automated nondestructive testing of the brazing defects in stainless steel core panels.
In this paper, a design method for the yarn tension sensor based on a surface acoustic wave is presented. When the yarn tension is applied to the sensor's doubly clamped beam (i.e., piezoelectric ...substrate), it is linearly related to the output frequency shift, which achieves the purpose of measuring the yarn tension. This paper deduces the functional relationship between the oscillation frequency shift of the sensor and the yarn tension. We put forward the choice of a piezoelectric substrate material, the choice of the piezoelectric die size, and the placement of interdigital transducers (IDTs) as the three key issues to be determined. By using the ANSYS software, we determined that the optimal piezoelectric substrate is quartz, and determined the optimal size of the die and the maximum strain area of the die. When IDTs are placed in the maximum strain area of the piezoelectric substrate, the sensor has the best sensitivity. We have designed and produced the sensor and also have tested the sensor. Experimental results: the range is 0-2 N, the linearity is 1.0112%, the hysteresis is 0.6153%, the repeatability is 1.1067%, the accuracy is 1.6205%, the maximum overload capacity is 200% (i.e., 4 N), and the fracture strength of the substrate is 5 N.
Radiation therapy toward malignancies is often ineffective owing to radioresistance of cancer cells. On the basis of anti-tumor properties of cordycepin, we examined the effects of cordycepin on ...sensitizing breast cancer cells toward radiotherapy. Cordycepin administration promoted G2/M arrest and apoptosis of MCF-7 and MDA-MB-231 cells resulting in restraining the proliferation of the cells in vitro and in vivo following irradiation. Mechanistic investigations showed that the breast cancer cells cultured with cordycepin harbored higher levels of intracellular reactive oxygen species (ROS) and incremental numbers of γ-H2AX foci after irradiation exposure. Importantly, cordycepin treatment down-regulated the expression levels of Nuclear factor erythroid 2-related factor (Nrf2) and a series of downstream genes, such as heme oxygenase-1 (HO-1), to enhance ROS in breast cancer cells exposed to irradiation. Together, our observations demonstrate that cordycepin treatment sensitizes breast carcinoma cells toward irradiation via Nrf2/HO-1/ROS axis. Thus, our findings provide novel insights into the function and the underlying mechanism of cordycepin in radiotherapy, and suggest that cordycepin might be employed as a radiosensitizer during radiotherapy toward breast cancer in a pre-clinical setting.
•Cordycepin sensitizes breast carcinoma cells toward irradiation covering TNBC.•Cordycepin administration induces DNA damage following irradiation.•Cordycepin hijacks Nrf2/HO-1/ROS axis to sensitize breast cancer cells toward IR.•Clinically, cordycepin might be employed as a radiosensitizer for breast cancer.
This article aims to investigate the protection of the intestine from ionizing radiation-induced injury by using D-galactose (D-gal) to alter the gut microbiome. In addition, this observation opens ...up further lines of research to further increase therapeutic potentials. Male C57BL/6 mice were exposed to 7.5 Gy of total body irradiation (TBI) or 13 Gy of total abdominal irradiation (TAI) in this study. After adjustment, D-gal was intraperitoneally injected into mice at a dose of 750 mg/kg/day. Survival rates, body weights, histological experiments and the level of the inflammatory factor IL-1β were observed after TBI to investigate radiation injury in mice. Feces were collected from mice for 16S high-throughput sequencing after TAI. Furthermore, fecal microorganism transplantation (FMT) was performed to confirm the effect of D-gal on radiation injury recovery. Intraperitoneally administered D-gal significantly increased the survival of irradiated mice by altering the gut microbiota structure. Furthermore, the fecal microbiota transplanted from D-gal-treated mice protected against radiation injury and improved the survival rate of recipient mice. Taken together, D-gal accelerates gut recovery following radiation injury by promoting the growth of specific microorganisms, especially those in the class Erysipelotrichia. The study discovered that D-gal-induced changes in the microbiota protect against radiation-induced intestinal injury. Erysipelotrichia and its metabolites are a promising therapeutic option for post-radiation intestinal regeneration.
Background
Breast cancer (BRCA) is the leading cause of cancer‐related death in women worldwide. Pre‐ and postoperative radiotherapy play a pivotal role in BRCA treatment but its efficacy remains ...limited and plagued by the emergence of radiation resistance, which aggravates patient prognosis. The long noncoding RNA (lncRNA)‐implicated mechanisms underlying radiation resistance are rarely reported. The aim of this study was to determine whether lncRNA HOX transcript antisense RNA (HOTAIR) modulated the radiosensitivity of breast cancer through HSPA1A.
Methods
A Gammacell 40 Exactor was used for irradiation treatment. Bioinformatic tools and luciferase reporter assay were adopted to explore gene expression profile and demonstrate the interactions between lncRNA, miRNA and target mRNA 3′‐untranslated region (3′‐UTR). The expression levels of certain genes were determined by real‐time PCR and western‐blot analyses. in vitro and in vivo functional assays were conducted by cell viability and tumorigenicity assays.
Results
The levels of oncogenic lncRNA HOTAIR were positively correlated with the malignancy of BRCA but reversely correlated with the radiosensitivity of breast cancer cells. Moreover, the expression levels of HOTAIR were positively associated with those of heat shock protein family A (Hsp70) member 1A (HSPA1A) in clinical BRCA tissues and HOTAIR upregulated HSPA1A at the mRNA and protein levels in irradiated BRCA cells. Mechanistically, miR‐449b‐5p restrained HSPA1A expression through targeting the 3′‐UTR of HSPA1A mRNA, whereas HOTAIR acted as a competing sponge to sequester miR‐449b‐5p and thereby relieved the miR‐449b‐5p‐mediated HSPA1A repression. Functionally, HOTAIR conferred decreased radiosensitivity on BRCA cells, while miR‐449b‐5p overexpression or HSPA1A knockdown abrogated the HOTAIR‐enhanced BRCA growth under the irradiation exposure both in vitro and in vivo.
Conclusions
LncRNA HOTAIR facilitates the expression of HSPA1A by sequestering miR‐449b‐5p post‐transcriptionally and thereby endows BRCA with radiation resistance.
Key points
Therapeutically, HOTAIR and HSPA1A may be employed as potential targets for BRCA radiotherapy. Our findings shed new light into the mechanism by which lncRNAs modulate the radiosensitivity of tumors.
Radiation therapy is a cornerstone of modern management methods for malignancies but is accompanied by diverse side effects. In the present study, we showed that food additives such as polysorbate 80 ...(P80) exacerbate irradiation-induced gastrointestinal (GI) tract toxicity. A 16S ribosomal RNA high-throughput sequencing analysis indicated that P80 consumption altered the abundance and composition of the gut microbiota, leading to severe radiation-induced GI tract injury. Mice harboring fecal microbes from P80-treated mice were highly susceptible to irradiation, and antibiotics-challenged mice also represented more sensitive to radiation following P80 treatment. Importantly, butyrate, a major metabolite of enteric microbial fermentation of dietary fibers, exhibited beneficial effects against P80 consumption-aggravated intestinal toxicity via the activation of G-protein-coupled receptors (GPCRs) and maintenance of the intestinal bacterial composition in irradiated animals. Moreover, butyrate had broad therapeutic effects on common radiation-induced injury. Collectively, our findings demonstrate that P80 are potential risk factors for cancer patients during radiotherapy and indicate that butyrate might be employed as a therapeutic option to mitigate the complications associated with radiotherapy.
Based on molecular dynamics (MD) simulation, the Young's moduli of carbon nanotubes are studied. The inter-atomic short-range interaction and long-range interaction of carbon nanotubes are ...represented by a second generation reactive empirical bond order (REBO) potential and Lennard–Jones (LJ) potential, respectively. The obtained potential expression is used to calculate the total potential energies of carbon nanotubes. Three types of single-walled carbon nanotubes (SWCNTs), armchair, zigzag and chiral tubules, are calculated, respectively. The computational results show that the Young's moduli of SWCNTs are in the range of 929.8±11.5GPa. From the simulation, the Young's moduli of SWCNTs are weakly affected by the tube chirality and tube radius. The numeric results are in good agreement with the existing experimental results.
Abstract-In this paper, we present the bulk acoustic wave (BAW), the sound-electricity reclamation (SER), and the insertion loss as the three key problems of a wavelet transform processor using ...surface acoustic wave devices. The solutions to these problems are achieved in this study. The more the number of electrode pairs for the interdigital transducer (IDT) is, the weaker the excited BAW is, so the BAW can be eliminated when the number of electrode pairs for IDT is large enough. The substrate material of a small electromechanical coupling coefficient (ECC) k 2 and the low-impedance load of IDT can eliminate SER. When the output ends of the wavelet transform processors are respectively connected to the amplifiers, their insertion losses can be compensated. X-112 o Y LiTaO 3 (small ECC k 2 ) is used as a substrate material to fabricate the wavelet transform processor.
Background
To identify radio‐responsive genes and explore the biological function of encoded proteins in non‐small cell lung cancer (NSCLC).
Methods
Radio‐responsive genes in irradiated H460 cells ...were screened from microarray data deposited in the Gene Expression Omnibus (GEO) database. A quantitative real time polymerase chain reaction assay was used to detect the expression of candidate radio‐responsive genes in irradiated cells. CCK‐8 assay, EDU assay, clone formation assay, immunofluorescence and flow cytometry were conducted to evaluate the biological function of B cell translocation gene 2 (BTG2) in NSCLC.
Results
Bioinformatic analysis using GES20549 showed that BTG2 was a radio‐responsive gene in irradiated H460 cells. The mRNA expression level of BTG2 was lower in H460 cells compared with that in BEAS‐2B normal lung epithelial cells. BTG2 expression was elevated upon IR exposure, in a dose‐dependent but not a time‐dependent manner. CCK‐8 and EDU assays revealed that BTG2 overexpression inhibited the growth rate of irradiated cells. Clone formation showed that elevated BTG2 promoted DNA damage of irradiated H460 cells. The number of γ‐H2AX foci induced by DNA damage was also markedly increased upon BTG2 overexpression. Flow cytometry showed that BTG2 increased IR‐induced cell apoptosis.
Conclusions
BTG2 may be a novel radio‐responsive factor and a promising therapeutic target for radiotherapy of NSCLC.
Radiation upregulated BTG2 expression in H460 cells in a dose‐dependent manner. BTG2 overexpression could inhibit the growth rate of irradiated cells, enhance the degree of radiation‐induced DNA damage, and promote radiation‐induced cell apoptosis in vitro.
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