GO/HTPB composite liner for anti-migration of small molecules

Hydroxyl-terminated polybutadiene/toluene diisocyanate(HTPB/TDI)system is widely used in composite solid propellants.The migrations of plasticizers and water molecules from solid propellants and surrounding environment to the inhibitor have always been the important issues.This study focuses on the preparation,characterization and anti-migration behavior of graphene oxide(GO)/HTPB nanocomposite liner.The GO/HTPB(GH)composite liners affect the migration of small molecules through a tighter cross-linked structure and weakening function of small molecule adsorption.The anti-migration performance of the liner at different temperatures was analyzed,and the influence of the added amount of GO on the anti-migration performance and adhesion performance was also systematically studied.The overall performance of the liner is optimized when the amount of GO filler is 0.3 wt%.After adding 0.3 wt%GO,the concentration of dioctyl sebacate(DOS)migrated into the liner is decreased by 23.28%,and the concentration of water molecules is decreased by 51.89%,indicating that the introduction of GO can significantly improve the anti-migration performance of the liner.In addition,the bond strength is greatly increased from 0.25 MPa to 0.95 MPa,which meets the application requirements of the current propellant system.This research provides an important way for the preparation of structure-function synergistic anti-migration composite liners.

Regeneration and anti-migration of sand waves associated with sand mining in the Taiwan Shoal

Sand waves in the Taiwan Shoal are characterized by two distinct spatial scales. Giant sand waves have a length of2 kilometers with height between 5 m and 25 m, whilst small sand waves is less than 100-m long with height less than 5 m between giant sand wave peaks(crests). A series of five high-resolution multi-beam echo-sounding surveys between 2012 and 2020 in the middle of Taiwan Shoal indicated that artificial dredging on the giant sand waves had caused sand wave reform and evolution. Overall, the removal of giant sand waves significantly affected the migration of small sand waves adjacent to the dredging site, with the latter on both sides of the former appear to migrate towards the dredging pit. Moreover, in the dredging area, new sand waves emerged with wavelength much smaller than the original giant sand waves, while the convergent pattern of the small sand waves tends to store and form the giant sand waves, which might spread far beyond the survey period.

Evaluation of anti-migration properties of biliary covered self-expandable metal stents

AIM: To assess anti-migration potential of six biliary covered self-expandable metal stents(C-SEMSs) by using a newly designed phantom model. METHODS: In the phantom model, the stent was placed in differently sized holes in a silicone wall and retracted with a retraction robot. Resistance force to migration(RFM) was measured by a force gauge on the stent end. Radial force(RF) was measured with a RF measurement machine. Measured flare structure variables were the outer diameter, height, and taper angle of the flare(ODF, HF, and TAF, respectively). Correlations between RFM and RF or flare variables were analyzed using a linear correlated model.RESULTS: Out of the six stents, five stents were braided, the other was laser-cut. The RF and RFM of each stent were expressed as the average of five replicate measurements. For all six stents, RFM and RF decreased as the hole diameter increased. For all six stents, RFM and RF correlated strongly when the stent had not fully expanded. This correlation was not observed in the five braided stents excluding the laser cut stent. For all six stents, there was a strong correlation between RFM and TAF when the stent fully expanded. For the five braided stents, RFM after full stent expansion correlated strongly with all three stent flare structure variables(ODF, HF, and TAF). The laser-cut C-SEMS had higher RFMs than the braided C-SEMSs regardless of expansion state.CONCLUSION: RF was an important anti-migration property when the C-SEMS did not fully expand. Once fully expanded, stent flare structure variables plays an important role in anti-migration.

Toxicarioside A inhibits SGC-7901 proliferation,migration and invasion via NF-κB/bFGF signaling

AIM:To investigate the inhibitory role of toxicarioside A on the gastric cancer cell line human gastric cancer cell line(SGC-7901) and determine the underlying molecular mechanism.METHODS:After SGC-7901 cells were treated with toxicarioside A at various concentrations(0.5,1.5,4.5,9.0 μg/mL) for 24 h or 48 h,cell viability was determined by 3-(4,5-dimethyl-thiazol-2-yl)-2,5-diphenyl2H-tetrazolium bromide assay,and the motility and invasion of tumor cells were assessed by the Transwell chamber assay.Immunofluorescence staining,reverse transcription polymerase chain reaction and Western blotting were performed to detect the expression of basic fibroblast growth factor(bFGF) and fibroblast growth factor receptor-1(FGFR1),and nuclear factorkappa B(NF-κB) activation was examined by electrophoretic mobility shift assay.RESULTS:The results showed that toxicarioside A was capable of reducing cell viability,inhibiting cell growth,and suppressing cell migration and invasion activities in a time-and dose-dependent manner in SGC-7901 cells.Further analysis revealed that not only the expression of bFGF and its high-affinity receptor FGFR1 but also the NF-κB-DNA binding activity were effectively blocked by toxicarioside A in a dose-dependent manner compared with the control group(P < 0.05 or P < 0.01).Interestingly,application of the NF-κB specific inhibitor,pyrrolidinedithiocarbamate(PDTC),to SGC-7901 cells significantly potentized the toxicarioside A-induced down-regulation of bFGF compared with the control group(P < 0.05).CONCLUSION:These findings suggest that toxicarioside A has an anti-gastric cancer activity and this effect may be achieved partly through down-regulation of NF-κB and bFGF/FGFR1 signaling.

Kinetic Migration of Diethylhexyl Phthalate in Functional PVC Films

Plasticizers that are generally used in plastics to produce flexible food packaging materials have proved to cause reproductive system problems and women＇s infertility. A long- term consumption may even cause cancer diseases. Hence a nano-scale layer, named as functional barrier layer, was deposited on the plastic surface to prevent plasticizer diethylhexyl phthalate＇s （DEHP） migration from plastics to foods. The feasibility of functional barrier layer i.e. SiOx coating through plasma enhanced chemical vapor deposition （PECVD） process was then described in this paper. We used Fourier transform infrared spectroscopy （FTIR） to analyze the chemical composition of coatings, scanning electron microscope （SEM） to explore the topography of the coating surfaces, surface profilemeter to measure thickness of coatings, and high-performance liquid chromatography （HPLC） to evaluate the barrier properties of coatings. The results have clearly shown that the coatings can perfectly block the migration of the DEHP from plastics to their containers. It is also concluded that process parameters significantly influence the block efficiency of the coatings. When the deposition conditions of SiOx coatings were optimized, i.e. 50 W of the discharge power, 4 ： 1 of ratio of O2 ： HMDSO, and ca.100 nm thickness of SiOx, 71.2% of the DEHP was effectively blocked.

Essential oil from Saussurea costus inhibits proliferation and migration of Eca109 cells via mitochondrial apoptosis and STAT3 signaling

Objective:To investigate the effect and its underlying molecular mechanisms of essential oil from Saussurea costus in esophageal cancer cell line Eca109.Methods:The chemical composition of essential oil from Saussurea costus was investigated by gas chromatography-mass spectrometry(GC-MS).The anti-proliferative,anti-migrative,and apoptotic effects of essential oil from Saussurea costus against Eca109 cells were analyzed.Moreover,the expression of proteins associated with cell cycle,metastasis,and apoptosis was determined.Results:GC-MS analysis showed that essential oil from Saussurea costus was predominantly comprised of sesquiterpenes.Saussurea costus essential oil inhibited the viability of Eca109 cells in a dose-and time-dependent manner with IC_(50) values of(24.29±1.49),(19.16±2.27)and(6.97±0.86)μg/mL at 12,24,and 48 h,respectively.The expression levels of target proteins in the cell cycle(phase G_(1)/S),including cyclin D1,p21,and p53,were affected by Saussurea costus essential oil.The essential oil also downregulated the expression of metastasis-related proteins MMP-9 and MMP-2.Moreover,it induced apoptosis of Eca109 cells through the mitochondrial pathway,as well as inhibition of STAT3 phosphorylation.Conclusions:The essential oil from Saussurea costus exhibited anti-proliferative,anti-migrative,and apoptotic effects on Eca109 cells,and could be further explored as a potential anti-esophageal cancer agent.