Research on the Analysis of Residual Stress in Heat Treatment of Bellows Using ABAQUS.

Taking austenitic stainless-steel bellows as the research object, a finite element model for the heat treatment of austenitic stainless-steel bellows was constructed based on ABAQUS CAE 2022. The physical properties of the bellows after the heat treatment were analyzed using experimental and simulated curve processing analysis methods. The changes in residual stress and deformation in relation to the bellows under different cooling times were explored, as well as the distribution of residual stress and deformation at a certain cooling time. The results show that as the cooling time of the heat treatment increases, the residual stress of the bellow decreases significantly, the reduction rate accelerates, and the degree of deformation gradually decreases. When the cooling time of the heat treatment is 900 s, the residual stress of the wave peak in the middle position of the bellow is relatively small, and the residual stress value of the wave valley along the axis direction does not change significantly. The deformation degree of the wave peak and valley axis direction is relatively uniform.

Long noncoding RNA DLEU2 promotes growth and invasion of hepatocellular carcinoma by regulating miR-30a-5p/PTP4A1 axis.

Increasing data indicate that long noncoding RNA (lncRNA) DLEU2 is implicated in carcinogenesis in multiple malignancies including hepatocellular carcinoma (HCC). However, the role and molecular mechanism by which lncRNA DLEU2 contributes to HCC remain unknown. The association of lncRNA DLEU2 with clinicopathological characteristics and prognosis in patients with HCC was analyzed by qRT-PCR, and public TCGA dataset. CCK-8, colony formation and Transwell assays were performed to verify the role of lncRNA DLEU2 in HCC. RNA immunoprecipitation (RIP), luciferase gene report and qRT-PCR assays were employed to uncover lncRNA DLEU2-spevific binding with miR-30a-5p. The effect of lncRNA DLEU2 and (or) miR-30a-5p on PTP4A1 expression was examined by Western blot analysis. As a consequence, we found that lncRNA DLEU2 was upregulated in HCC tissue samples and associated with distant metastasis and poor survival in patients with HCC. Knockdown of lncRNA DLEU2 impaired HCC cell proliferation, colony formation and invasion, but ectopic expression of lncRNA DLEU2 abolished these effects. Furthermore, lncRNA DLEU2 harbored a negative correlation and specific binding with miR-30a-5p in HCC cells. Knockdown of lncRNA DLEU2 upregulated miR-30a-5p, but downregulated its target PTP4A1, and miR-30a-5p abrogated lncRNA DLEU2-induced tumor-promoting effects and PTP4A1 upregulation. Taken together, our findings demonstrate that lncRNA DLEU2 promotes growth and invasion of HCC cells by regulating miR-30a-5p/ PTP4A1 axis.

The coupling interaction of soil organic carbon stock and water storage after vegetation restoration on the Loess Plateau, China.

Vegetation restoration may increase the soil organic carbon stock (SOCS) but decrease the soil water storage (SWS) of terrestrial ecosystems in arid and semiarid regions. To guarantee the sustainability of restoration, it is critical to evaluate the coupling interaction of SOCS and SWS. Here, we examined the spatial distributions of SOCS and SWS across a 0-200 cm soil profile in a grassland, forestland and shrubland on the Loess Plateau and determined the driving factors that affected their variations. Our results showed that SOCS and SWS varied across the 0-200 cm soil profile and considerably accumulated in the deep soil layers (100-200 cm). In comparison to SOCS, SWS generally had higher relative benefits in most studied plant communities, which ensured sustainable restoration. In addition, land use played a less important role than local environmental conditions in determining the variations in SOCS and SWS. Specifically, the interaction between SOCS and SWS was mainly strong in the surface soil layers (0-20 cm). Topography was a predominant factor that affected SOCS and SWS in the deep soil layers (100-200 cm), while soil texture was a stable driving factor influencing their variations across the whole soil profile (0-200 cm). Given the low moisture consumption of grasslands and the lowest root mean square deviation (RMSD) of Hippophae rhamnoides, we proposed an advanced scenario for ecological restoration on the Loess Plateau: establishing reasonably large Hippophae rhamnoides patches with fewer edges in a contiguous grassland matrix. Furthermore, this scenario should be tailored to local environmental conditions, such as soil water, texture and topography, followed by natural vegetation succession.

[Construction of recombinant adenovirus vector expressing shRNAs targeting COX-2, AKT1 and PIK3R1 gene and its inhibition effect on proliferation of human gastric adenocarcinoma].

OBJECTIVE: To construct a recombinant adenovirus vector that expresses small hairpin RNAs (shRNA) against COX-2, AKT1 and PIK3R1 gene and to evaluate its potential for suppressing the cell proliferation of human gastric adenocarcinoma SGC701 cell in vitro and in vivo, which will enable the development of a gene therapy protocol for the treatment of human gastric adenocarcinoma. METHODS: Three strips of shRNA targeting AKT1, COX-2 and PIK3R1, was subcloned into adenovirus expression vector. After verification, it was amplified and titered. The recombinant adenovirus expression vector was infected into human gastric adenocarcinoma SGC7901 cells in vitro and the infected cells were injected in nude mice. The mRNA and protein expression levels of AKT1, COX-2 and PIK3R1 were determined by real-time PCR and Western blot respectively. Cell proliferation in vitro was determined by methyl thiazolyltetrazolium (MTT) assay and flow cytometry, tumor growth in vivo was measured by volume of tumor in nude mice. RESULTS: Restriction digestion and sequencing analysis showed that the rAd5-C-A-P adenovirus expression vector was constructed successfully. It significantly inhibited the expression of AKT1, COX-2 and PIK3R1, and cell growth was inhibited over 70% as indicated by MTT assay and accompanied with G0/G1 phase arrest. Cell growth on matrigel matrix showed that the rAd5-C-A-P transfected cells were detached from the matrix or grew in a scattered clustering pattern, indicating poor cell growth activities in 2-D matrigel. Tumor growth in nude mice in the C + A + P group was inhibited (P<0.01). CONCLUSION: shRNA targeting COX-2, AKT1 and PIK3R1 down regulated significantly the expression of the three genes in a sequence-specific manner, exerted proliferation inhibition effect on SGC7901 cells in vitro and in vivo.

[Inhibitory effect of adenovirus-mediated short hairpin RNA targeting P85 and Akt1 on growth of human gastric adenocarcinoma cell].

OBJECTIVE: To construct a short hairpin RNA(shRNA) adenovirus vector targeting P85 and protein kinase B1 (PKB1/Akt1) and study its effects on the growth of SGC-7901 human gastric adenocarcinoma cells. METHODS: P85 and Akt1 shRNA expression frames were subcloned to pGSadeno adenovirus vector with homologous recombination technology to construct pGSadeno-P85 + Akt1 (rAd5-P + A) vector. After screening and amplification, the recombinant adenovirus vector was digested with PacI and transfected into SGC-7901 cells and then its titer and transfection efficiency were detected with fluorescent microscope. P85 and Akt1 mRNA protein expression was identified with real-time PCR and Western blot. The proliferative activity of tumor cells was evaluated with MTT assay and flow cytometry in vitro. rAd5-HK and rAd5-P + A mediated by adenovirus were injected into the established subcutaneous SGC-7901 gastric adenocarcinoma in nude mice. During the observation period of 21 days, tumor volume was measured every 3 days to further testify the anti-tumor effect of rAd5-P + A on the SGC-7901 gastric adenocarcinoma cells and cell in situ apoptosis was detected with TUNEL assay. RESULTS: The adenovirus vector rAd5-P + A was successfully constructed and it dramatically downregulated P85 and Akt1 mRNA expression in SGC-7901 gastric adenocarcinoma cells. Compared with a control group of SGC-7901 cells and cells transfected with general adenovirus rAd5-HK as control, P85 and Akt1 protein expression 48 h and 72 h after rAd5-P + A transfection was decreased by 57.5% and 63.7%, 67.8% and 75.6% with statistical significance (P = 0.005, P = 0.003). Cell proliferative activity in rAd5-P + A transfected cells was suppressed from the second day (P < 0.001) and the decreased P85 and Akt1 expression was accompanied by 5.9% -7.1% decrease of S phase fraction and 12.1% - 13.7% increase of G0/G1 phase. The tumor volume of rAd5-P + A treated group was smaller than that of the control and rAd5-HK group with statistical significance (F = 9.871, P = 0.025). Moreover, rAd5-P + A could induce cell in situ apoptosis. CONCLUSIONS: Adenovirus-mediated targeting P85 and Akt1 shRNA can inhibit the growth of SGC-7901 human gastric adenocarcinoma cells and this may provide a new strategy of combination gene therapy in gastric adenocarcinoma.

Expression of p-Akt and COX-2 in gastric adenocarcinomas and adenovirus mediated Akt1 and COX-2 ShRNA suppresses SGC-7901 gastric adenocarcinoma and U251 glioma cell growth in vitro and in vivo.

Cyclooxygenase-2 (COX-2) and Protein kinase B (PKB/Akt) play a crucial role in the formation of many malignant tumors and have been shown to be the important therapeutic targets. In the present study, we examined immunohistochemical expression of phosphorylated Akt (p-Akt) and COX-2 in 45 gastric adenocarcinomas with different tumor grades. Then, adenovirus-mediated small hairpin RNA (shRNA) expression vectors rAd5-Akt1+COX-2 (rAd5-A+C) that target sequences of human COX-2 and Akt1 were used to examine the inhibitory effects on cell proliferation, invasion and apoptosis in SGC7901 gastric adenocarcinoma and U251 glioma cells. Cell growth was inhibited by over 70%, as indicated by a MTT assay, and was accompanied by G1/G0 phase arrest in the rAd5-A+C treated group, indicating poor cell growth activities. The number of cells invading through the matrigel in the rAd5-A+C treated group was significantly decreased (36.2+/-3.1) compared with that of the control group SGC7901 (105.0+/-4.0) and the nonsense sequence group rAd5-HK (102.5+/-6.4). In addition, the tumor volumes in the SGC7901 subcutaneous nude mouse model treated with rAd5-A+C was significantly smaller than those of the control group and nonsense sequence group rAd5-HK. When COX-2 and Akt1 were dramatically downregulated, Ki-67, CyclinD1, MMP-2, MMP-9 and Bcl-2 were also downregulated. Our results demonstrated that p-Akt and COX-2 were overexpressed in gastric adenocarcinomas and their expression levels were elevated with the ascending order of tumor malignancy; rAd5-A+C targeting COX-2 and Akt1 downregulated their expression significantly in a sequence-specific manner, exerting inhibitory effects on SGC7901 and U251 cell proliferation, invasion and apoptosis. In conclusion, our data suggest a novel mechanism for the regulation of malignant tumor cell growth and provide evidence for combined gene therapy for malignant tumors.

Inhibitory effects of adenovirus mediated COX-2, Akt1 and PIK3R1 shRNA on the growth of malignant tumor cells in vitro and in vivo.

Cyclooxygenase-2 (COX-2) and phosphatidylinositol 3-kinase (PI3K)/Akt play a critical role in the formation of many malignant tumors, and have been shown to be important therapeutic targets. In the present study, small hairpin RNA (shRNA) expression constructs that target sequences of human COX-2, Akt1 and PIK3R1 were used to examine the proliferation and invasion inhibition effects on SGC7901 gastric adenocarcinoma cells and U251 glioma cells. Cell growth was inhibited by over 70%, as indicated by a MTT assay, and was accompanied by G1/G0 phase arrest in the shRNA treated group, indicating poor cell growth activities. The number of cells invading through the matrigel in the shRNA treated group were significantly decreased (26.4+/-4.6) compared with that of the control group (105+/-4.0) and the nonsense sequence group (102.5+/-6.4). In addition, the tumor volumes in the SGC7901 subcutaneous nude mouse model treated with shRNA was significantly smaller than those of the control group and nonsense sequence group. When COX-2, Akt1 and PIK3R1 were dramatically downregulated, proliferating cell nuclear antigen (PCNA), CyclinD1 and matrix metalloproteinases (MMP-2, MMP-9) were downregulated, while tissue-inhibitor of metalloproteinase-2 (TIMP-2) and P53 were upregulated. Our results demonstrated that shRNA targeting COX-2, Akt1 and PIK3R1 downregulates their expression significantly in a sequence-specific manner, exerting proliferation and invasion inhibition effects on SGC7901 and U251 cells. In conclusion, our data suggest a novel mechanism for the regulation of malignant tumor cell growth and provide evidence for new combinatory gene therapy for malignant tumors.

Inhibitory effects of adenovirus mediated Akt1 and PIK3R1 shRNA on the growth of malignant tumor cells in vitro and in vivo.

Phosphatidylinositol 3-kinase (PI3K)/Akt plays a critical role in the formation of many malignant tumors, and has been shown to be an important therapeutic target. In the present study, small hairpin RNA (shRNA) expression constructs that target sequences of human Akt1 and PIK3R1 were used to examine the proliferation and invasion inhibition effects on SGC7901 gastric adenocarcinoma cells and U251 glioma cells. Cell growth was inhibited by over 60%, as indicated by a MTT assay, and was accompanied by G(1)/G(0) phase arrest in the shRNA treated group, indicating poor cell growth activities. The number of cells invading through the matrigel in the shRNA treated group were significantly decreased (51.6 +/- 3.9) compared with that of the control group (105 +/- 4.0) and the nonsense sequence group (102.5 +/- 6.4). In addition, the tumor volumes in the SGC7901 subcutaneous nude mouse model treated with shRNA were significantly smaller than those of the control group and nonsense sequence group. When Akt1 and PIK3R1 were dramatically downregulated, proliferating cell nuclear antigen (PCNA), CyclinD1 and matrix metalloproteinases (MMP-2, MMP-9) were downregulated, while tissue-Inhibitor of Metalloproteinase-2 (TIMP-2) and p53 were upregulated. Our results demonstrated that shRNA targeting Akt1 and PIK3R1 downregulates their expression significantly in a sequence-specific manner, exerting proliferation and invasion inhibition effects on SGC7901 and U251 cells. In conclusion, our data suggests a novel mechanism for the regulation of malignant tumor cell growth and provides evidence for new combinatory gene therapy for malignant tumors.

[Inhibitory effects of targeting protein kinase B1 and cyclooxygenase-2 shRNA upon human gastric adenocarcinoma cell growth].

OBJECTIVE: To construct a short hairpin RNA (shRNA) adenovirus vector targeting Akt1 (protein kinase B1, PKB1/Akt1) and cyclooxygenase-2 (COX-2) and study its effects on the growth of SGC-7901 human gastric adenocarcinoma cell. METHODS: Adenovirus pGSadeno-Akt1 + COX-2 (rAd5-A + C) vector was constructed and transfected into SGC-7901 cell. The proliferative activity of tumor cell was evaluated by MTT assay and flow cytometry in vitro. rAd5-HK and rAd5-A + C were injected into the established subcutaneous SGC-7901 gastric adenocarcinoma in nude mice. During the observation period of 21 days, tumor volume was measured every 3 days to further observe the anti-tumor effects of rAd5-A + C on SGC-7901 cell and cell situ apoptosis was detected by TUNEL assay. RESULTS: After transfection of constructed adenovirus vector rAd5-A + C into SGC-7901 cell, cell proliferative activity in rAd5-A + C treatment group was significantly suppressed, and cell cycle indicated that control group SGC-7901 and no-load group rAd5-A + C cells in G0/G1, S and G2/M phases accounted for the total number of cells 49.8%, 35.2%, 15.0% and 50.8%, 36.5%, 12.7% respectively. While the treatment group rAd5-A + C in G0/ G1, S and G2/M phases accounted for the total number of cells 68.1%, 21.8% and 10.1% respectively. The tumor volume in treatment group was lower than that of control and no-load groups and the difference had statistical significance (F = 3.679, P = 0.043) and rAd5-A + C could induce the apoptosis of tumor cell. CONCLUSION: Adenovirus-mediated Akt1 and COX-2 shRNA can inhibit the growth of SGC-7901 human gastric adenocarcinoma cell. It may provide a new strategy for gastric cancer gene therapy.