Single-turnover and multiple-turnover measurement of phytoplankton photosynthesis parameters using variable light pulse induced fluorescence

Using a measurement system based on fluorescence induced by variable pulse light, photosynthesis parameters of chlorella pyrenoidosa are obtained, employing single-turnover and multiple-turnover protocols under darkadapted and light-adapted conditions. Under the light-adapted condition,σ’PSII is larger, and F’v/F’m（ST） and F’v/F’m（MT） are smaller than those of the dark-adapted condition, but the corresponding parameters possess good linear correlations.Fm（MT）, F’m（MT）, Fv/Fm（MT） and F’v/F’m（MT） which are measured using the multipleturnover protocol, are larger than those of the single-turnover protocol. The linear correlation coefficient between Fm（ST） and Fm（MT） is 0.984,and Fv/Fm（MT） = 1.18 Fv/Fm（ST） The linear correlation coefficient between F’m（ST） and F’m（MT） is 0.995, and F’v/F’m（MT） = 1.36 F’v/F’m/（ST）.

Synthesis of newly cationic surfactant based on dimethylaminopropyl amine and their silver nanoparticles:Characterization;surface activity and biological activity

The chemical structure of newly synthesized cationic surfactants based on Schiff base was confirmed using Fourier transform infrared spectroscopy,proton nuclear magnetic resonance spectroscopy,and mass spectroscopy.The synthesized surfactants were used in the synthesis of silver nanoparticles by a simple one-step method.The silver nanoparticle（AgNPs） formation was confirmed using transmission electron microscopy（TEM）,electron diffraction（SAED）,dynamic light scattering（DLS）,and energy dispersive X-ray spectroscopy（EDX）.The structure of the surfactant played an important role in the synthesis process.Increasing the hydrophobic chain length,the stability,and the amount of surfactant increased the quantity of AgNPs formed.The surface activity of the synthesized cationic surfactants was determined using surface tension measurements at three different temperatures.The synthesized surfactants showed a high tendency toward adsorption and micellization.Increasing the hydrophobic chain length of the synthesized surfactant increased its adsorption.Screening the synthesized cationic surfactants and their nano-form against bacteria and fungi showed that they are highly effective.The silver nanoparticles enhanced the biological activity of the synthesized cationic surfactants.