Modelling of Glulam beams pre-stressed by compressed wood

Finite element models were, in the first time, developed to simulate the pre-stressing behaviour of Glulam beams with insertion of compressed wood blocks, which were further used to simulate the structural behaviour of the pre-stressed beams subjected to subsequent destructive bending. Here, both the Glulam and compressed wood were modelled as orthotropic elasto-viscoplastic materials. The moisture-dependent, including spring back, swelling of the compressed wood block and the creep of the Glulam were considered in the modelling. The models developed were validated against the corresponding experimental results, with reasonably good correlation in terms of the free swelling, the precamber, initial stress state of the Glulam beams reinforced and load-deflection relationships. With validated models, further studies were then undertaken to investigate effects of the thickness, depth and spacing of compressed wood blocks on the precamber, initial bending stiffness and ultimate load carrying capacity of the beams pre-stressed. The results indicate that there are significant enhancements on the precamber (up to 1/288 of the deflection/span ratio), the initial bending stiffness (up to 23.8%) and the ultimate load carrying capacity (up to 10.4%

<inf>Blast response of aluminium/thermoplastic polyurethane sandwich panels – experimental work and numerical analysis</inf>

© 2019 Elsevier Ltd This article presents experimental and numerical results following blast tests on a polyether grade thermoplastic polyurethane (TPU). Aluminium alloy (AA) 2024-T3 skins were used as facings to enhance the blast resistance of sandwich structures with TPU cores and varying thicknesses. The experimental results highlighted an improvement in blast resistance with the addition of skins to the TPU core. Increasing the thickness of the TPU core in the sandwich panels served to increase the blast resistance of the structure. For example a 20 mm core offered a blast resistance that was 50.2% higher than an equivalent 5 mm core and 71.2% higher than a plain (i.e. no skin) 5 mm TPU core. Numerical simulations of the blast response of the TPU panels were conducted by converting the explosive loading regime applied to the panels to a simplified pressure pulse loading. Good agreement was obtained between the numerical and experimental results for the back face deflection profiles through the central cross-sections of the panels

Competitive Binding Between Id1 and E2F1 to Cdc20 Regulates E2F1 Degradation and Thymidylate Synthase Expression to Promote Esophageal Cancer Chemoresistance

Purpose: Chemoresistance is a major obstacle in cancer therapy. We found that fluorouracil (5-FU)-resistant esophageal squamous cell carcinoma cell lines, established through exposure to increasing concentrations of 5-FU, showed upregulation of Id1, IGF2, and E2F1. We hypothesized that these genes may play an important role in cancer chemoresistance. Experimental Design: In vitro and in vivo functional assays were performed to study the effects of Id1–E2F1–IGF2 signaling in chemoresistance. Quantitative real-time PCR, Western blotting, immunoprecipitation, chromatin immunoprecipitation, and dual-luciferase reporter assays were used to investigate the molecular mechanisms by which Id1 regulates E2F1 and by which E2F1 regulates IGF2. Clinical specimens, tumor tissue microarray, and Gene Expression Omnibus datasets were used to analyze the correlations between gene expressions and the relationships between expression profiles and patient survival outcomes. Results: Id1 conferred 5-FU chemoresistance through E2F1-dependent induction of thymidylate synthase expression in esophageal cancer cells and tumor xenografts. Mechanistically, Id1 protects E2F1 protein from degradation and increases its expression by binding competitively to Cdc20, whereas E2F1 mediates Id1-induced upregulation of IGF2 by binding directly to the IGF2 promoter and activating its transcription. The expression level of E2F1 was positively correlated with that of Id1 and IGF2 in human cancers. More importantly, concurrent high expression of Id1 and IGF2 was associated with unfavorable patient survival in multiple cancer types. Conclusions: Our findings define an intricate E2F1-dependent mechanism by which Id1 increases thymidylate synthase and IGF2 expressions to promote cancer chemoresistance. The Id1–E2F1–IGF2 regulatory axis has important implications for cancer prognosis and treatment. ©2015 AACR.postprin

Cancer cell-secreted IGF2 instigates fibroblasts and bone marrow-derived vascular progenitor cells to promote cancer progression

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Effects of Thioglycolic Acid on Parthenogenetic Activation of Xenopus Oocytes

BACKGROUND: Existing in Permanent-wave solutions (PWS), thioglycolic acid (TGA) is widely used in hairdressing industry for its contribution to hair styling. However, the toxicity of TGA, especially its reproductive toxicity, gradually calls the attention of more and more researchers. METHOD: In this work, xenopus oocytes were pretreated with different concentration of TGA, and then activated by calcium ionophore A23187. During culture, the oocytes activation rates were taken note at different time after adding calcium ionophore A23187. At the end of the culture period, the nuclear status was detected under confocal microscope. In addition, some other samples were collected for Western-Blotting analysis. RESULT: TGA significantly inhibited the oocytes activation rate and pronuclear formation. It may be resulted from the inhibition of the degradation of p-ERK1, Mos and CyclinB2. CONCLUSION: TGA inhibits in vitro parthenogenetic activation of xenopus oocytes with inhibited the degradation of proteins involved in mitogenic-activated protein kinase (MAPK) and maturation-promoting factor (MPF) pathways