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Introduction to wastewater treatment
Published in Nick F. Gray, Water Science and Technology: An Introduction, 2017
The various growth phases on the microbial growth curve (Figure 10.18) can be represented quantitatively. The net microbial growth rate (mg L−1 day−1) can be expressed as follows: dXdt=μX−kdX where X is the concentration of microorganisms (mg L−1), φ is the specific growth rate (day−1), kd is the endogenous decay coefficient (day−1) and t is the time in days. The integrated form of this equation when plotted on semi-log arithmetic graph paper results in a straight line, hence the term logarithmic growth phase. The equation assumes that all the microorganisms are viable, and while this may be true for a test tube culture, it cannot be the case for a wastewater treatment unit with long retention times. It is, however, assumed that a constant fraction of the organisms within the biological treatment unit will remain viable.
Synthesis and application of cationic fluorocarbon surfactants
Published in Journal of Dispersion Science and Technology, 2023
Saipeng Zhang, Mingxin Zhang, Xingjiang Liu, Liuhe Wei
Mouse macrophage RAW 264.7 toxicity evaluation method (MTT): RAW 264.7 cells in logarithmic growth were resuspended in DMEM cell culture medium (10% FBS and 1% double antibodies), then inoculated with 5 × 104/well cells in 96-well plates and incubated at 37 °C, 5% CO2 for 12-16 h. The medium was aspirated and washed with PBS. Five different concentrations of the tested samples (DMEM medium containing 20% FBS (Gibco) was used as a positive control group) were added separately from fresh medium (DMEM basal medium containing 1% double antibodies), and five replicate wells were set for each concentration, and incubated at 37 °C for 48 h in a 5% CO2 incubator, followed by the addition of 20 μL MTT (5 mg/mL), and then incubated in the incubator for 4 h. After incubation for 48 h at 37 °C in a 5% CO2 incubator, 20 μL of MTT (5 mg/mL) was added, followed by incubation for 4 h in the incubator. The results were recorded.
Synthesis, characterization, and biological activity of sterically hindered fluorine-containing platinum(II) complexes
Published in Journal of Coordination Chemistry, 2023
Pan Zhao, Lihua Chen, Jing Yang, Xiali Liao, Bo Yang, Chuanzhu Gao
Antiproliferative activities of Y1–Y5 and positive controls: cisplatin and picoplatin against the cancer cell lines (A549, SW480, HCT116, MCF-7, and HepG2) and normal cell line (LO2) were evaluated by MTT assay. First, tumor cells of the logarithmic growth phase were taken for the experiment and inoculated in 96-well cell culture plates, and the cell density was adjusted so that there were about 2 × 104 cells per well. Then, Y1–Y5 and the positive controls cisplatin and picoplatin were dissolved in DMF and diluted with medium to bring the concentration of DMF below 0.2%. The final volume of each well was 200 μL, and the cells were incubated for 48 h. Subsequently, MTT reagent (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) was added to the wells, incubated for 4 h, the supernatant cleared away, and the purple soild was dissolved with addition of 200 μL DMSO. The absorbance value (OD) of each well at 490 nm was measured by a multifunctional enzyme marker, and the inhibition rate was calculated and evaluated for its in vitro antiproliferative activity based on the IC50 value of the complexes. Each test was repeated three times. The half-maximal inhibitory concentrations (IC50) were obtained by drawing cell viability (%) against complex concentration (µM).
Response surface methodology to optimize self-flocculation harvesting of microalgae Desmodesmus sp.CHX1
Published in Environmental Technology, 2022
Bangxi Zhang, Linhai Liu, Xiaoai Lin, Zhicheng Xu, Wenhai Luo, Longzao Luo
The representative microalgae Desmodesmus sp.CHX1 was obtained from a local oxidation pond based on the method reported previously [12]. Microalgae cells were cultivated to attain the logarithmic growth in the Blue Green Algae medium (i.e. BG-11 medium) and then collected using 1 μm filter papers to transfer into a series of 1 L flasks containing 0.8 L synthetic wastewater, which was prepared using the BG-11 medium. The synthetic wastewater was formulated with a chemical oxygen demand (COD) of 1000 mg L-1 organic matter, ammonium nitrogen (NH4-N) of 200 mg L−1, and total phosphorus (TP) of 50 mg L−1. The pH of the synthetic wastewater was 7.4. Microalgae cells were inoculated in the synthetic wastewater with the initial concentration of 0.1 g cell·L−1 based on the dry weight. An illumination incubator with continuous white fluorescent light (6000 lx) and a constant temperature of 30°C was used for microalgae cultivation.