The 2003 flood of the Muda River reached 1 , 340 m 3 / s at Ladang Victoria and adversely impacted 45,000 people in Malaysia. A flood control remediation plan proposed a levee height based on a 50-year discharge of 1 , 815 m 3 / s obtained from hydrologic models. This design discharge falls outside the 95% confidence intervals of the flood frequency analysis based on field measurements. Instream sand and gravel mining operations also caused excessive riverbed degradation, which largely off sets apparent benefits for flood control. Pumping stations have been systematically required at irrigation canal intakes. Several bridge piers have also been severely undermined and emergency abutment protection works were needed in several places. Instream sand and gravel mining activities should be replaced with offstream mining in the future.
PurposeThe aim of this study was to investigate the potential of the synergetic triple therapeutic combination encompassing bismuth oxide nanoparticles (BiONPs), cisplatin (Cis), and high dose rate (HDR) brachytherapy with Ir-192 source in breast cancer and normal fibroblast cell line.MethodsIn vitro models of breast cancer cell lines (MCF-7, MDA-MB-231) and normal fibroblast cell line (NIH/3T3) were employed. Cellular localization and cytotoxicity studies were conducted prior to inspection on the radiosensitization effects and generation of reactive oxygen species (ROS) on three proposed radiosensitizers: BiONPs, Cis, and BiONPs-Cis combination (BC). The optimal, non-cytotoxic concentration of BiONPs (0.5 mM) and the 25% inhibitory concentration of Cis (1.30 µM) were applied. The radiosensitization effects were evaluated by using a 0.38 MeV Iridium-192 HDR brachytherapy source over a prescribed dose range of 0 Gy to 4 Gy.ResultsThe cellular localization of BiONPs was visualized by light microscopy and accumulation of the BiONPs within the vicinity of the nuclear membrane was observed. Quantification of the sensitization enhancement ratio extrapolated from the survival curves indicates radiosensitization effects for MCF-7 and MDA-MB-231 when treated with BiONPs, Cis, and BC. However, NIH/3T3 cells exhibited contradictive behavior as it only reacted towards the BC combination. Nonetheless, the MCF-7 cell line loaded with BC shows the highest SER of 4.29. ROS production analysis, on the other hand, shows that Cis and BC radiosensitizers generated the highest free radicals in comparison to BiONPs alone.ConclusionA BiONPs-Cis combination was unveiled as a novel approach that offers promising radiosensitization enhancement that will increase the efficiency of tumor control while preserving the normal tissue at a reduced dose. This data is the first precedent to prove the synergetic implication of BiONPs, Cis, and HDR brachytherapy that will be beneficial for future chemoradiotherapy strategies in cancer care.
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