Seismic performance of steel-reinforced concrete-filled rectangular steel tubes after exposure to non-uniform fire.

In actual engineering, non-uniform fire boundary circumstances including single-sided fire, neighboring or related two-sided fire, and three-sided fire, are created due to the varying placements of the columns. In this paper, the seismic performance of SRCFST members subjected to non-uniform fire was investigated by the method of finite element simulation. First of all, the P-Δ curve, ductility coefficient, stiffness, and energy dissipation of the members following non-uniform fire were investigated. As the number of fire surfaces decreases, the maximum overfire temperature at the center of the section decreases, damage decreases, stiffness degradation decreases, and energy dissipation capacity increases. Next, the load distribution of each component in the SRCFST member was calculated using a three-sided fire as an example, the results show that steel tubes play the most dominant role in the seismic performance after fire, followed by steel sections and concrete the least. Last, a parametric study of the key variables influencing the ductility coefficient was carried out.

[Moderate-to-vigorous Physical Activities and Gestational Weight Gains during the Second and Last Trimesters of Pregnancy].

OBJECTIVE: To determine the level of moderate-to-vigorous physical activities (MVPA) and its relationship with gestational weight gains (GWG) in the second and the last trimesters of pregnancy. METHODS: A prospective study was conducted in Chengdu on 362 healthy pregnant women at the 24-28 gestation weeks who delivered a singleton. Demographic data and pre-pregnancy body mass were collected using a questionnaire. Weight gains at the gestation weeks of 24-28 and 32-36 were measured for the first two trimesters and the last trimester of pregnancy. The Denmark self-reported physical activity scale was used for measuring the duration and intensity of physical activities. Multiple linear regression models were established to determine the relationship between MVPA and GWG. RESULTS: The last trimester had lower average daily MVPA 〔(0.76±0.93) h〕 compared with the second trimester 〔(1.61±1.61) h, t=9.056, P<0.001〕. About 74.6% of the participants met the PA recommendations for the second trimester, compared with 60.5% for the last trimester (χ2=16.387, P<0.001). The participants experienced an average GWG of (7.36±3.78) kg during the first two trimesters, and (5.80±2.57) kg during the last trimester, corresponding to a growth rate of (0.30±0.15) kg/week for the first two trimesters and (0.51±0.22) kg/week for the last trimester. Compared with the most inactive group, the participants with medium PA experienced less GWG 〔(5.34±2.91) kg vs.(6.26±2.54) kg, P<0.05〕 and a lower GWG rate 〔(0.48±0.26) kg/week vs.(0.56±0.20) kg/week, P<0.05〕 during the last trimester. Age, gestational week, ethnicity, pre-pregnant BMI, GDM, pre-pregnant smoking and employment were associated with GWG and the GWG rates during the first two trimesters and the third trimester (P<0.05). Compared with the most inactive group, low 〔-0.358(-0.691--0.026)〕 and medium 〔-0.762(-1.486- -0.037)〕 PA were associated with lower GWG during the last trimester. Moderate PA was associated with a lower GWG rate 〔-0.071(-0.133--0.008)〕 after adjustment for gestational age, energy intake, pre-pregnancy BMI and other potential confounders. CONCLUSIONS: Insufficient physical activities are a serious problem in the pregnant women of Chengdu over the last two trimesters. Appropriate MVPA in the last trimester of pregnancy may reduce GWG and GWG rates.

Radiosensitization effect of hsa-miR-138-2-3p on human laryngeal cancer stem cells.

BACKGROUND: Treatments that target cancer stem cells play an important role in the controlling and eliminating of tumor initiation as well as in development, progression, and chemotherapy/radiotherapy resistance. In our previous study, we cultured and harvested human laryngeal cancer stem cells (CSCs) and applied microRNA biochips to screen differentially expressed miRNAs that were related to radiation tolerance in irradiated human laryngeal CSCs. According to the predicted genes and pathways of differential miRNAs target, down-regulated expression of hsa-miR-138-2-3p under radiation was thought to play a key role in enhancing the radio-sensitivity in human laryngeal squamous cancer stem cells. METHOD: To investigate the radiational enhancement of hsa-miR-138-2-3p, we transfected hsa-miR-138-2-3p mimics that were synthesized based on the sequences of hsa-miR-138-2-3p in vitrointo human laryngeal CSCs (Hep-2, M2e, and TU212 cell lines) to make hsa-miR-138-2-3p overexpressed, and the tumorous specialities of CSCs, like cell proliferation, invasion, apoptosis, cell cycle arrest, and DNA damage were evaluated by CCK-8 assay, clone formation assay, invasion assay, flow cytometry, and comet assay. Furthermore, we explored the signal transduction pathways that regulated the cancer stem cell initiation, development, invasion, apoptosis and cell cycle arrest, which were controlled by hsa-miR-138-2-3p. RESULT: Overexpressed hsa-miR-138-2-3p played a key role in many anti-cancer biological processes in human laryngeal CSCs: (1) it decreased laryngeal CSCs proliferation and invasion in response to radiotherapy; (2) it increased the proportion of early and late apoptosis in laryngeal CSCs after radiation, raised G1 phase arrest in laryngeal CSCs after radiation, and decreased the proportion of S stage cells of cell cycle that were related to radio-resistance in laryngeal CSCs; (3) it down-regulated the expression of ß-catenin in Wnt signal pathway that was related to the tolerance of laryngeal CSCs to radiotherapy; (4) it down-regulated the expression of YAP1 in Hippo signal pathway that regulated cell proliferation, invasion and apoptosis; (5) it up-regulated the expression of p38 and JNK1 in MAPK signal pathway that was concerned to radio-sensitivity. CONCLUSION: In the present study, it was found that hsa-miR-138-2-3p regulated the Wnt/ß-catenin pathways, the Hippo/YAP1 pathways, and the MAPK/p38/JNK1 pathways that were involved in cell proliferation, invasion, apoptosis, cell cycle arrest, radio-resistance and radio-sensitivity in laryngeal CSCs. These results will be useful for a better understanding of the cell biology of hsa-miR-138-2-3p in laryngeal CSCs, and for serving hsa-miR-138-2-3p as a promising biomarker and as a target for diagnosis and for novel anti-cancer therapies for laryngeal cancers.