ABSTRACT
Nano-sized titanium dioxide in the aquatic environment has a potential impact on the environment and human health. In this study, the impact of pH value, dissolved organic matter (DOM) and divalent cations (Ca(2+)) on the stability of titanium dioxide nanoparticles (nano-TiO2) in an aqueous environment was investigated in batch tests. The results showed that the particle size of nano-TiO2 was not sensitive to pH value but was inversely proportional to zeta potential. The nano-TiO2 becomes more stable with surface zeta potential, accompanied by small particle size and high dispersion. In the presence of DOM, the particle size was smaller and the stability of nano-TiO2 could be enhanced. This might be a synergistic effect of the ligand exchange and electrostatic force. Particle size increased with the addition of Ca(2+) and the stability decreased.
Subject(s)
Nanoparticles/chemistry , Titanium/chemistry , Water Pollutants, Chemical/chemistry , Calcium/chemistry , Humic Substances , Hydrogen-Ion Concentration , Osmolar Concentration , Particle Size , Surface PropertiesABSTRACT
In this study, fourteen small interfering RNAs (siRNAs) were synthesized for targeting of coding gene sequences, specific 5'-leader sequence of mRNA and 3'-end sequence of the Infectious bronchitis virus (IBV) genome. The expression of viral genes in Vero-E6 cells was detected by real-time PCR. Obtained results indicated that the majority of siRNAs could effectively inhibit the expression of viral genes. The inhibition effect of siRNAs significantly differed among various genes and sites on the virus genome.
Subject(s)
Gene Expression , Infectious bronchitis virus/growth & development , RNA, Small Interfering/genetics , 3' Untranslated Regions/genetics , 5' Untranslated Regions/genetics , Animals , Chlorocebus aethiops , Genome, Viral , Infectious bronchitis virus/genetics , RNA, Viral/biosynthesis , RNA, Viral/genetics , Reverse Transcriptase Polymerase Chain Reaction , Vero CellsABSTRACT
Starting with the occurrence of Cyclops in drinking water sources and its danger to drinking water safety, we extensively investigated the nature of its excess propagation by analyzing the effect of living space and predator pressure in the food chain on its survival. Then we developed an ecological project using fish biomanipulation, different to the conventional fishery culture technique, to control excess propagation of Cyclops. The control effects on Cyclops of four species of fish were investigated experimentally at a stocking density of 30 g/m3 of water. Results showed that the food habit of the fish had a significant influence on the biological control of Cyclops. The propagation of Cyclops could be controlled effectively and also the water quality improved simultaneously by stocking filter-feeding fish, such as silver carp (Hypophthalmichthys molitrix) and bighead carp (Aristichthys nobilis). However, herbivorous Ctenopharyngodon idellus and omnivorous Cyprinus carpio had no obvious biological effects on controlling the growth of Cyclops and restoring water quality. The results further proved that under conditions of proper poly-culture densities of silver carp and bighead carp, the number of Cyclops might be controlled at very low levels and eutrophication might be abated by removing nutrients from the water body.