STUDY ON IN VITRO ANTI-TUMOR ACTIVITY OF BIDENS BIPINNATA L. EXTRACT

We studied the in vitro anti-tumor activity of Bidens Bipinnata L. extract. MTT assay was used to investigate the inhibitory effect of different concentrations of the extracts on human hepatocellular carcinoma (HepG2) cell lines and human cervical carcinoma (Hela) cell lines, and the IC50 values were calculated. The Bidens Bipinnata L. extract had different degrees of inhibitory effects on these two cells, and when exposure time was 48 h, the inhibition rate reached its peak, with IC50 values of 14.80 μg/mL and 13.50 μg/mL respectively. The Bidens Bipinnata L. extract had a good inhibitory effect on human HepG2 cell lines and Hela cell lines, and thus has certain development prospects

Field Study of Residual Forces Developed in PHC Pipe Piles

A large-scale field testing program for the study of residual forces in Pre-stressed High-strength Concrete (PHC) pipe piles is presented in this paper. Five open-ended PHC pipe piles with 13 or 18 m embedded length were installed and used for static loading tests at a building site in Hangzhou, China. All the piles were instrumented with Fiber Bragg Grating (FBG) strain gauges. The residual forces in these piles were recorded during and after installation. The measured load transfer data along a pile during the static loading tests are reported. The effect of the residual forces on the interpretation of the load transfer behavior is discussed. The field data show that residual forces along the installed piles increase approximately exponentially to the neutral plane and then reduce towards the toe. The residual force decreases with time to a stable value after pile jacking due to the secondary interaction between the pile and the disturbed soil around the pile and other factors. The large residual forces along the PHC pipe piles affect significantly the evaluation of the pile load distributions, and thus the shaft and toe resistances. The conventional bearing capacity theory tends to overestimate the shaft resistance at positions above the neutral plane, and underestimate both the shaft resistance at positions below the neutral plane and the toe resistance for open-ended PHC pipe piles founded in stratified soils.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Use of a waste-based binder for high water content soil treatment

In recent years, roads in Singapore have had to be constructed on reclaimed land using marine clay as fill materials. Improving the engineering properties of the high water content, soft clayey soil in the reclaimed land in a cost-effective way before road construction becomes a challenge. It is expensive to treat high water content soil using cement because the amount of cement required would be excessive. In this paper, a study on the potential use of a waste-based binder as a substitute for portland cement for the improvement of high water content soil is presented. A series of laboratory tests were carried out to assess the undrained shear strength of binder-treated marine clay compared with the use of cement. The test results indicated that for soil with a high initial water content, the use of waste-based binder could shorten the curing period by about 20% while achieving the same unconfined compressive strength or increase the undrained shear strength at 14 or 28 days by 20 to 50% compared with the marine clay treated with cement of the same dosage. The aging effect of the waste-based binder was stronger. A microstructural study also shows that there are interlocking matrixes produced between soil particles in the binder-treated soil that contributes toward the increase in shear strength in the soil

Stress Monitoring on GFRP Anchors Based on Fiber Bragg Grating Sensors

Glass fiber-reinforced polymer (GFRP) bolts have been widely used in some applications of grouted anchors because of the advantages of better resistance to corrosion, high strength-to-weight ratio, low electromagnetic properties, and so on. This study presents a field test to assess the feasibility of fiber Bragg grating (FBG) sensors in monitoring the stress profile of GFRP anchors during pulling test. Two GFRP anchors were fully instrumented with FBG sensors and then installed into the ground using a drilling and grouting method. To measure the stress profile along test anchors, seven bare FBG sensors were arranged in a single optical fiber and then embedded in the middle of GFRP bolts in the process of extrusion molding. The procedure for embedding bare FBG sensors into GFRP bolts is introduced first. Then, the axial forces and shear stresses that were calculated from the measurements of the FBG sensors are discussed. The field test results indicate that the embedded FBG technology was feasible to monitor the stress state of GFRP anchors during pulling