Ultrasonic attenuation spectroscopy for multivariate statistical process control in nanomaterial processing

Ultrasonic attenuation spectroscopy （UAS） is an attractive process analytical technology （PAT） for on-line real-time characterisation of slurries for particle size distribution （PSD） estimation. It is however only applicable to relatively low solid concentrations since existing instrument process models still cannot fully take into account the phenomena of particle-particle interaction and multiple scattering, leading to errors in PSD estimation. This paper investigates an alternative use of the raw attenuation spectra for direct multivariate statistical process control （MSPC）. The UAS raw spectra were processed using principal component analysis. The selected principal components were used to derive two MSPC statistics, the Hotelling＇s T2 and square prediction error （SPE）. The method is illustrated and demonstrated by reference to a wet milling process for processinR nanoparticles.

Spectrum-Toxicity Correlation Study Revealed the Influence of the Nine-Time Steaming and Sun Drying Method on Hepatotoxic Components of Polygoni Multiflori Radix

Objective:Polygoni Multiflori Radix(PM)is a traditional herbal medicine with repeated reports of liver injury events in recent years.We wondered whether the classical processing method,namely,nine-time steaming and sun drying(NSSD),had toxicity-attenuating effects on PM and the relationships between toxicity and times of processing,as well as with the alteration trends of its compounds.Materials and Methods:The chemical fingerprints of different PM extracts were developed using ultra-high-performance liquid chromatography.The spectrum-toxicity correlation between the chemical fingerprints and hepatocellular toxicity was analyzed with multiple correlation analysis.Results:The results suggested that the hepatotoxicity of NSSD processing products markedly decreased with the repeated steaming and sun drying,which was obviously superior to the product processed by the modern method.Comprehensive analysis revealed that the contents of cis-stilbene glycoside and emodin-8-O-β-D-glucoside related to liver injury susceptibility were reduced with the times of NSSD processing,which was consistent with the decreased trend of hepatocellular toxicity.After the five times of NSSD,the contents of them as well as the hepatotoxicity of PM were steady.Moreover,we found that the contents of catechin and physcion declined rapidly after the one time of NSSD and then remained stable until the nine times of NSSD.Based on the fact,they could be utilized to indicate whether PM products were processed by steaming and sun drying.Conclusions:This paper confirmed that the NSSD had a good influence on the toxicity attenuating to PM and found four compounds which could apply for the quality control of PM.

A surface plasmon resonance imaging system for the stimulated living cell analysis

In this paper, a surface plasmon resonance imaging(SPRI) system for cell analysis is developed for obtaining the surface plasmon resonance(SPR) signal from the interactions between cells and different stimuli. The system is constructed with a red laser light source, a P-polarizer, a glass prism, a 5× objective lens, a charge coupled device(CCD) camera, a gold sensor chip, a polydimethylsiloxane(PDMS) reaction well and a mechanical scanning device. The system is applied to mapping living cells in response to stimuli by characterization of the refractive index(RI) changes. Cell responses to K+ in KCl solutions with concentrations of 5 mmol/L, 20 mmol/L, 50 mmol/L and 100 mmol/L are collected, which indicates that the SPRI method can distinguish the concentration of the stimuli. Furthermore, cell responses to epidermal growth factor(EGF) and vascular endothelial growth factor(VEGF) are studied independently. The binding of EGF receptor(EGFR) and EGF is collected as the first signal, and the internal change in cells is recorded as the second signal. The cell response to VEGF is different from that to EGF, which indicates that the SPRI as a label-free, real-time, fast and quantitative method has a potential to distinguish the cell responses to different stimuli.