For the first time, we report photoacoustic (PA) signal detection in a cell placed within the Michelson interferometer cavity in an attempt to relate photoacoustic effect to the Michelson fringe shift as a result of c...For the first time, we report photoacoustic (PA) signal detection in a cell placed within the Michelson interferometer cavity in an attempt to relate photoacoustic effect to the Michelson fringe shift as a result of changes in the cell. Both detection schemes were investigated using IR absorption and their sensitivities compared. Signals related to Michelson interferometer fringe and PA effect have shown good correlations with each other using different samples including some essential oils and their corresponding plant part from which the essential oil is usually obtained. Results were encouraging and will open the door widely to use the combined Michelson interferometer-photoacoustic spectroscopy (PAS) in trace gas detection for different applications.展开更多
Enterococcus species are one of the leading causes of nosocomial infections, which are difficult to treat specially with the rise of its Vancomycin resistant. Studies of Enterococcus isolates are essential for epidemi...Enterococcus species are one of the leading causes of nosocomial infections, which are difficult to treat specially with the rise of its Vancomycin resistant. Studies of Enterococcus isolates are essential for epidemiological investigation. Typing Enterococci is often based on the traditional phenotypic as well as genotypic methods. In this study Fourier-transform infrared (FTIR) spectroscopy is used as a novel phenotypic approach to the typing of Enterococci. FTIR spectroscopy results compared to antibiotic susceptibility testing and PCR amplification of Vancomycin gene results;the analysis showed that, 6 isolates were positive for Van gene (4 of VanA, 1 of VanB and 1 VanA plus VanB). Three of VanA and VanA plus VanB were resistant to all antibiotic tested (Ampicillin, Teicoplamin and Vancomycin) and VanB was found to be sensitive. FTIR spectroscopy (first derivatives) divided the isolates into 8 groups. 3 groups of VanA (4 isolates), one of VanB (one isolate), one of VanA plus VanB (one isolate) and the other 13 Enterococcus isolates were divided into 3 clusters. The study demonstrated that FTIR spectroscopy has good discriminative capacity and high reproducibility as compared to other techniques.展开更多
文摘For the first time, we report photoacoustic (PA) signal detection in a cell placed within the Michelson interferometer cavity in an attempt to relate photoacoustic effect to the Michelson fringe shift as a result of changes in the cell. Both detection schemes were investigated using IR absorption and their sensitivities compared. Signals related to Michelson interferometer fringe and PA effect have shown good correlations with each other using different samples including some essential oils and their corresponding plant part from which the essential oil is usually obtained. Results were encouraging and will open the door widely to use the combined Michelson interferometer-photoacoustic spectroscopy (PAS) in trace gas detection for different applications.
文摘Enterococcus species are one of the leading causes of nosocomial infections, which are difficult to treat specially with the rise of its Vancomycin resistant. Studies of Enterococcus isolates are essential for epidemiological investigation. Typing Enterococci is often based on the traditional phenotypic as well as genotypic methods. In this study Fourier-transform infrared (FTIR) spectroscopy is used as a novel phenotypic approach to the typing of Enterococci. FTIR spectroscopy results compared to antibiotic susceptibility testing and PCR amplification of Vancomycin gene results;the analysis showed that, 6 isolates were positive for Van gene (4 of VanA, 1 of VanB and 1 VanA plus VanB). Three of VanA and VanA plus VanB were resistant to all antibiotic tested (Ampicillin, Teicoplamin and Vancomycin) and VanB was found to be sensitive. FTIR spectroscopy (first derivatives) divided the isolates into 8 groups. 3 groups of VanA (4 isolates), one of VanB (one isolate), one of VanA plus VanB (one isolate) and the other 13 Enterococcus isolates were divided into 3 clusters. The study demonstrated that FTIR spectroscopy has good discriminative capacity and high reproducibility as compared to other techniques.
