Inclusion and mechanical properties of ODS-RAFM steels with Y, Ti, and Zr fabricated by melting

Qiu Guo-xing,Wei Xu-li,Bai Chong,Miao De-jun,Cao Lei,Li Xiao-ming 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.7

Two groups of oxide dispersionestrengthened reduced-activation ferritic/martensitic steels (A and B) were prepared by adding Y, Ti, and Zr into steels through vacuum induction melting to investigate the inclusions, microstructures, mechanical properties of the alloys. Results showed that particles with Y, Ti, and Zr easily formed. Massive, Zr-rich inclusions were found in B steel. Density of micron inclusions in A steel was 1.42 1014 m3 , and density of nanoparticles was 3.61 1016 m3 . More and finer MX carbides were found in steel tempered at 650 C, and yield strengths (YS) of A and B steel were 714±2 and 664±3.5 MPa. Thermomechanical processing (TMP) retained many dislocations, which improved the mechanical properties. YSs of A and B treated by TMP were 725±3 and 683±4 MPa. The existence of massive Zr-rich inclusions in B steels interrupted the continuity of the matrix and produced microcracks (fracture), which caused a reduction in mechanical properties. The presence of fine prior austenite grain size and inclusions was attributed to the low DBTTs of the A steels; DBTTs of A650 and A700 alloy were 79 and 65 C. Tempering temperature reduction and TMP are simple, readily useable methods that can lead to a superior balance of strength and impact toughness in industry applications

Ganoderma Lucidum Polysaccharides Target a Fas/Caspase Dependent Pathway to Induce Apoptosis in Human Colon Cancer Cells

Liang, Zengenni,Guo, Yu-Tong,Yi, You-Jin,Wang, Ren-Cai,Hu, Qiu-Long,Xiong, Xing-Yao Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.9

Ganoderma lucidum polysaccharides (GLP) extracted from Ganoderma lucidum have been shown to induce cell death in some kinds of cancer cells. This study investigated the cytotoxic and apoptotic effect of GLP on HCT-116 human colon cancer cells and the molecular mechanisms involved. Cell proliferation, cell migration, lactate dehydrogenase (LDH) levels and intracellular free calcium levels ($[Ca^{2+}]i$) were determined by MTT, wound-healing, LDH release and fluorescence assays, respectively. Cell apoptosis was observed by scanning and transmission electron microscopy. For the mechanism studies, caspase-8 activation, and Fas and caspase-3 expression were evaluated. Treatment of HCT-116 cells with various concentrations of GLP (0.625-5 mg/mL) resulted in a significant decrease in cell viability (P< 0.01). This study showed that the antitumor activity of GLP was related to cell migration inhibition, cell morphology changes, intracellular $Ca^{2+}$ elevation and LDH release. Also, increase in the levels of caspase-8 activity was involved in GLP-induced apoptosis. Western blotting indicated that Fas and caspase-3 protein expression was up-regulated after exposure to GLP. This investigation demonstrated for the first time that GLP shows prominent anticancer activities against the HCT-116 human colon cancer cell line through triggering intracellular calcium release and the death receptor pathway.

Rapid and Sensitive Detection of Salmonella in Chickens Using Loop-Mediated Isothermal Amplification Combined with a Lateral Flow Dipstick

( Zhi-ke Liu ),( Qiu-yu Zhang ),( Ning-ning Yang ),( Ming-guo Xu ),( Jin-feng Xu ),( Ming-long Jing ),( Wen-xing Wu ),( Ya-dong Lu ),( Feng Shi ),( Chuang-fu Chen ) 한국미생물생명공학회(구 한국산업미생물학회) 2019 Journal of microbiology and biotechnology Vol.29 No.3

Salmonellosis is a highly contagious bacterial disease that threatens both human and poultry health. Tests that can detect Salmonella in the field are urgently required to facilitate disease control and for epidemiological investigations. Here, we combined loop-mediated isothermal amplification (LAMP) with a chromatographic lateral flow dipstick (LFD) to rapidly and accurately detect Salmonella. LAMP primers were designed to target the Salmonella invA gene. LAMP conditions were optimized by adjusting the ratio of inner to outer primers, MgSO₄ concentration, dNTP mix concentration, amplification temperature, and amplification time. We evaluated the specificity of our novel LAMP-LFD method using six Salmonella species and six related non-Salmonella strains. All six of the Salmonella strains, but none of the non-Salmonella strains, were amplified. LAMP-LFD was sensitive enough to detect concentrations of Salmonella enterica subsp. enterica serovar Pullorum genomic DNA as low as 89 fg/μl, which is 1,000 times more sensitive than conventional PCR. When artificially contaminated feed samples were analyzed, LAMP-LFD was also more sensitive than PCR. Finally, LAMP-LFD gave no false positives across 350 chicken anal swabs. Therefore, our novel LAMP-LFD assay was highly sensitive, specific, convenient, and fast, making it a valuable tool for the early diagnosis and monitoring of Salmonella infection in chickens.

An Analysis of the Focus Variation Microscope and Its Application in the Measurement of Tool Parameter

Lin Yuan,Tong Guo,Zhongjun Qiu,Xing Fu,Xiaotang Hu 한국정밀공학회 2020 International Journal of Precision Engineering and Vol.21 No.12

Ultra-precision manufacturing is essential to the production of workpieces of the highest quality in terms of form accuracy, surface accuracy, and integrity. Compared with physical and chemical material removal methods, it has the advantages of high efficiency, high flexibility, and low cost. Because of the direct interaction between the workpiece and the tool during the process of ultra-precision manufacturing, the geometrical parameters of the tool directly affect the surface quality of the workpiece and need to be measured accurately and comprehensively. However, due to the large surface slopes of some tools, some three-dimensional measurement methods cannot measure their geometrical parameters because of limited maximum measurement angle. In this work, we build a focus variation system to make three-dimensional measurements of tools and extract their geometrical parameters. The data processing procedures and the selection of experimental parameters are analyzed in detail using simulations and experiments. Furthermore, we use a step height standard to verify the high accuracy of the measurement system and a roughened fl at surface to evaluate the measurement noise and vertical resolution. Measurements of the parameters of a round nose cutting tool and the surface texture parameters of a grinding tool are conducted and indicate that the focus variation system is suitable for measuring the geometrical parameters of tools for ultra-precision manufacturing.

β-elemene Induces Caspase-dependent Apoptosis in Human Glioma Cells in vitro through the Upregulation of Bax and Fas/FasL and Downregulation of Bcl-2

Li, Chen-Long,Chang, Liang,Guo, Lin,Zhao, Dan,Liu, Hui-Bin,Wang, Qiu-Shi,Zhang, Ping,Du, Wen-Zhong,Liu, Xing,Zhang, Hai-Tao,Liu, Yang,Zhang, Yao,Xie, Jing-Hong,Ming, Jian-Guang,Cui, Yu-Qiong,Sun, Ying Asian Pacific Journal of Cancer Prevention 2014 Asian Pacific journal of cancer prevention Vol.15 No.23

Background: ${\beta}$-elemene, extracted from herb medicine Curcuma wenyujin has potent anti-tumor effects in various cancer cell lines. However, the activity of ${\beta}$-elemene against glioma cells remains unclear. In the present study, we assessed effects of ${\beta}$-elemene on human glioma cells and explored the underlying mechanism. Materials and Methods: Human glioma U87 cells were used. Cell proliferation was determined with MTT assay and colony formation assay to detect the effect of ${\beta}$-elemene at different doses and times. Fluorescence microscopy was used to observe cell apoptosis with Hoechst 33258 staining and change of glioma apoptosis and cell cycling were analyzed by flow cytometry. Real-time quantitative PCR and Western-blotting assay were performed to investigated the influence of ${\beta}$-elemene on expression levels of Fas/FasL, caspase-3, Bcl-2 and Bax. The experiment was divided into two groups: the blank control group and ${\beta}$-elemne treatment group. Results: With increase in the concentration of ${\beta}$-elemene, cytotoxic effects were enhanced in the glioma cell line and the concentration of inhibited cell viability ($IC_{50}$) was $48.5{\mu}g/mL$ for 24h. ${\beta}$-elemene could induce cell cycle arrest in the G0/G1 phase. With Hoechst 33258 staining, apoptotic nuclear morphological changes were observed. Activation of caspase-3,-8 and -9 was increased and the pro-apoptotic factors Fas/FasL and Bax were upregulated, while the anti-apoptotic Bcl-2 was downregulated after treatment with ${\beta}$-elemene at both mRNA and protein levels. Furthermore, proliferation and colony formation by U87 cells were inhibited by ${\beta}$-elemene in a time and does-dependent manner. Conclusions: Our results indicate that ${\beta}$-elemene inhibits growth and induces apoptosis of human glioma cells in vitro. The induction of apoptosis appears to be related with the upregulation of Fas/FasL and Bax, activation of caspase-3,-8 and -9 and downregulation of Bcl-2, which then trigger major apoptotic cascades.

Effects of pulsed laser surface remelting on microstructure, hardness and lead-bismuth corrosion behavior of a ferrite/martensitic steel

Hao Wang,Qian Yuan,Linjiang Chai,Ke Zhao,Ning Guo,Jun Xiao,Xing Yin,Bin Tang,Yuqiong Li,Shaoyu Qiu 한국원자력학회 2022 Nuclear Engineering and Technology Vol.54 No.6

A typical ferritic/martensitic (F/M) steel sheet was subjected to pulsed laser surface remelting (LSR) andcorrosion test in lead-bismuth eutectic (LBE) at 550 C. There present two modification zones withdistinct microstructures in the LSRed specimen: (1) remelted zone (RZ) consisting of both bulk d-ferritegrains and martensitic plates and (2) heat-affected zone (HAZ) below the RZ, mainly composed ofmartensitic plates and high-density precipitates. Martensitic transformation occurs in both the RZ andthe HAZ with the Kurdjumov-Sachs and Nishiyama-Wassermann orientation relationships followedconcurrently, resulting in scattered orientations and specific misorientation characteristics. Hardnessesof the RZ and the HAZ are 364 ± 7 HV and 451 ± 15 HV, respectively, considerably higher than that of thematrix (267 ± 3 HV). In oxygen-saturated and oxygen-depleted LBE, thicknesses of oxide layers developed on both the as-received and the LSRed specimens increase with prolonging corrosion time (oxidelayers always thinner under the oxygen-depleted condition). The corrosion resistance of the LSRed F/Msteel in oxygen-saturated LBE is improved, which can be attributed to the grain-refinement acceleratedformation of dense FeeCr spinel. In oxygen-depleted LBE, the growth of oxide layers is very low withboth types of specimens showing similar corrosion resistance