In this study, we proposed a rapid and sensitive method for quantification and spatial distribution of salicylic acid in film tablets using FT-Raman spectroscopy with multivariate curve resolution(MCR). For this purpo...In this study, we proposed a rapid and sensitive method for quantification and spatial distribution of salicylic acid in film tablets using FT-Raman spectroscopy with multivariate curve resolution(MCR). For this purpose, the constituents of film tablets were identified by using FT-Raman spectroscopy, and then eight different concentrations of salicylic acid tablets were visualized by Raman mapping. MCR was applied to mapping data to expose the active pharmaceutical ingredients in the presence of other excipients by monitoring distribution maps and combination of FT-Raman mapping with MCR enabled the determination of lower salicylic acid concentrations. In addition, the distribution of major excipient, lactose, was examined in the tablet form. A calibration curve was obtained by plotting the intensity of the Raman signal at 1635 cm^(-1) versus the concentration of salicylic acid and the correlation was found to be linear within the range of 0.5%–3.9% with a correlation coefficient of 0.99. The limit of detection for the technique was determined 0.35%. The ability of the technique to quantify salicylic acid in tablet test samples was also investigated.展开更多
A conformal multi-resolution time-domain( CMRTD) method is presented for modeling curved objects. The effective dielectric constant and area weighting are used to derive the update equations of CMRTD. The backward sca...A conformal multi-resolution time-domain( CMRTD) method is presented for modeling curved objects. The effective dielectric constant and area weighting are used to derive the update equations of CMRTD. The backward scattering bistatic radar cross sections( RCS) of the dielectric cylinder and ellipsoid are used to validate the proposed method. The results show that the proposed conformal method is more accurate to deal with the complex curved objects in electromagnetic simulations.展开更多
Background: Pyrazinamide (PZA) is one of the most important drugs for tuberculosis (TB) treatment, however, its susceptibility is not routinely tested. High-resolution melting (HRM) curve analysis has been widely used...Background: Pyrazinamide (PZA) is one of the most important drugs for tuberculosis (TB) treatment, however, its susceptibility is not routinely tested. High-resolution melting (HRM) curve analysis has been widely used for many applications. In this study, HRM assay was developed and evaluated for the detection of PZA resistance in Mycobacterium tuberculosis clinical isolates. Methods: Ninety five M. tuberculosis clinical isolates with different susceptibility patterns to anti-TB drugs were used to evaluate this assay. Isolates were phenotypically (Bactec MGIT 960) and genotypically (HRM and pncA gene sequencing) analysed for PZA resistance. Results: Bactec MGIT 960 analysis revealed that 29 of the 95 M. tuberculosis isolates were PZA resistant. In comparison to the Bactec MGIT 960, HRM showed a sensitivity of 47.7% and specificity of 74.6%, and the overall agreement between the two methods was 68.4%. Based on DNA sequencing, a correlation of 0.67 (significant at p-value pncA mutations was observed. PZA resistance was strongly associated with multi-drug resistant (MDR)-TB as it was shown in 79.3% of the MDR isolates included in the study. Conclusion: HRM is simple and useful for screening clinical M. tuberculosis isolates for PZA resistance, however, further modifications to improve its performance are required.展开更多
Hydrophobic hydration,whereby water spontaneously structures around hydrophobic and amphiphilic molecules,plays a key role in the process of surfactant micelle formation and micellar oil solubilization.Using vibration...Hydrophobic hydration,whereby water spontaneously structures around hydrophobic and amphiphilic molecules,plays a key role in the process of surfactant micelle formation and micellar oil solubilization.Using vibrational Raman multivariate curve resolution spectroscopy,we characterized changes in the hydrophobic hydration occurring within nonionic alkylphenol ethoxylate surfactant Tergitol NP-12 micelles as a function of oil solubilization.We report trends in the changes of hydrophobic hydration depending on the chain length of the oil as well as the presence of a halogen atom in the oil chemical structure.Changes in hydrophobic hydration directly correlate to changes in the physical properties of the micellar solution,including cloud point and micelle hydrodynamic diameter.We compare hydrophobic hydration of Tergitol NP-12 to nonionic linear alkyl ethoxylate surfactant Makon TD-12 and ionic sodium dodecyl sulfate and observe similar trends;the molecular structure of the oil has the largest impact on the hydrophobic hydration.We believe these studies contribute to a fundamental understanding of the importance of hydrophobic hydration in surfactant and oil aggregates,especially as it relates to micellar oil solubilization,and provide insight into how the molecular solubilizate can impact micellar structure,size,and stability.展开更多
3,4-Bis（4＇-aminofurazano-3＇）furoxan（DATF）, one of a new generation of high energy density materials, shows lots of interesting properties such as lower sensitivity, excellent thermal stability and superior deton...3,4-Bis（4＇-aminofurazano-3＇）furoxan（DATF）, one of a new generation of high energy density materials, shows lots of interesting properties such as lower sensitivity, excellent thermal stability and superior detonation perfor- mance in chemistry and physics. In this paper, on-line infrared（IR） spectroscopy was used to monitor the synthesis process of DATF. The concentration profiles and IR spectra of the components were determined by analyzing the IR data via principal component analysis（PCA）, evolving factor analysis（EFA） and multivariate curve resolution-alternating least squares（MCR-ALS）. The geometric configurations of reactant, intermediates and product were optimized with the density functional theory（DFT） at B3LYP/6-3 l＋G（d, p） level. Their vibrational frequencies and IR spectra were obtained on the basis of vibrational analysis. The result obtained by the chemometric resolution methods agreed well with that obtained by quantum chemical calculation method, which demonstrated the reliability of the proposed chemometric resolution methods. The unstable intermediate 3-amino-4-oxycyanofurazan（AOF） was confirmed via comparing the IR spectra resloved by chemometric resolution methods with those calculated by B3LYP/6-3 l＋G（d,p） and analyzed by MCR-ALS. Finally, the possible synthesis mechanism of DATF was deduced by analyzing the above IR spectra.展开更多
基金supported by grant from Gazi University, Project no: 02/2012-27
文摘In this study, we proposed a rapid and sensitive method for quantification and spatial distribution of salicylic acid in film tablets using FT-Raman spectroscopy with multivariate curve resolution(MCR). For this purpose, the constituents of film tablets were identified by using FT-Raman spectroscopy, and then eight different concentrations of salicylic acid tablets were visualized by Raman mapping. MCR was applied to mapping data to expose the active pharmaceutical ingredients in the presence of other excipients by monitoring distribution maps and combination of FT-Raman mapping with MCR enabled the determination of lower salicylic acid concentrations. In addition, the distribution of major excipient, lactose, was examined in the tablet form. A calibration curve was obtained by plotting the intensity of the Raman signal at 1635 cm^(-1) versus the concentration of salicylic acid and the correlation was found to be linear within the range of 0.5%–3.9% with a correlation coefficient of 0.99. The limit of detection for the technique was determined 0.35%. The ability of the technique to quantify salicylic acid in tablet test samples was also investigated.
基金Supported by the National Natural Science Foundation of China(61172024)the Funding of Jiangsu Innovation Program for Graduate Education and the Fundamental Research Funds for the Central Universities(CXZZ12-0156)
文摘A conformal multi-resolution time-domain( CMRTD) method is presented for modeling curved objects. The effective dielectric constant and area weighting are used to derive the update equations of CMRTD. The backward scattering bistatic radar cross sections( RCS) of the dielectric cylinder and ellipsoid are used to validate the proposed method. The results show that the proposed conformal method is more accurate to deal with the complex curved objects in electromagnetic simulations.
文摘Background: Pyrazinamide (PZA) is one of the most important drugs for tuberculosis (TB) treatment, however, its susceptibility is not routinely tested. High-resolution melting (HRM) curve analysis has been widely used for many applications. In this study, HRM assay was developed and evaluated for the detection of PZA resistance in Mycobacterium tuberculosis clinical isolates. Methods: Ninety five M. tuberculosis clinical isolates with different susceptibility patterns to anti-TB drugs were used to evaluate this assay. Isolates were phenotypically (Bactec MGIT 960) and genotypically (HRM and pncA gene sequencing) analysed for PZA resistance. Results: Bactec MGIT 960 analysis revealed that 29 of the 95 M. tuberculosis isolates were PZA resistant. In comparison to the Bactec MGIT 960, HRM showed a sensitivity of 47.7% and specificity of 74.6%, and the overall agreement between the two methods was 68.4%. Based on DNA sequencing, a correlation of 0.67 (significant at p-value pncA mutations was observed. PZA resistance was strongly associated with multi-drug resistant (MDR)-TB as it was shown in 79.3% of the MDR isolates included in the study. Conclusion: HRM is simple and useful for screening clinical M. tuberculosis isolates for PZA resistance, however, further modifications to improve its performance are required.
基金Army Research Office,Grant/Award Number:W911NF-18-1-0414David and Lucile Packard Foundation,Grant/Award Number:2019-69664National Science Foundation,Grant/Award Number:CHE-2004050。
文摘Hydrophobic hydration,whereby water spontaneously structures around hydrophobic and amphiphilic molecules,plays a key role in the process of surfactant micelle formation and micellar oil solubilization.Using vibrational Raman multivariate curve resolution spectroscopy,we characterized changes in the hydrophobic hydration occurring within nonionic alkylphenol ethoxylate surfactant Tergitol NP-12 micelles as a function of oil solubilization.We report trends in the changes of hydrophobic hydration depending on the chain length of the oil as well as the presence of a halogen atom in the oil chemical structure.Changes in hydrophobic hydration directly correlate to changes in the physical properties of the micellar solution,including cloud point and micelle hydrodynamic diameter.We compare hydrophobic hydration of Tergitol NP-12 to nonionic linear alkyl ethoxylate surfactant Makon TD-12 and ionic sodium dodecyl sulfate and observe similar trends;the molecular structure of the oil has the largest impact on the hydrophobic hydration.We believe these studies contribute to a fundamental understanding of the importance of hydrophobic hydration in surfactant and oil aggregates,especially as it relates to micellar oil solubilization,and provide insight into how the molecular solubilizate can impact micellar structure,size,and stability.
基金Supported by the National Natural Science Foundation of China（No.21175106） and the Specialized Research Fund for the Doctoral Program of Higher Education, China（No.20126101110019）.
文摘3,4-Bis（4＇-aminofurazano-3＇）furoxan（DATF）, one of a new generation of high energy density materials, shows lots of interesting properties such as lower sensitivity, excellent thermal stability and superior detonation perfor- mance in chemistry and physics. In this paper, on-line infrared（IR） spectroscopy was used to monitor the synthesis process of DATF. The concentration profiles and IR spectra of the components were determined by analyzing the IR data via principal component analysis（PCA）, evolving factor analysis（EFA） and multivariate curve resolution-alternating least squares（MCR-ALS）. The geometric configurations of reactant, intermediates and product were optimized with the density functional theory（DFT） at B3LYP/6-3 l＋G（d, p） level. Their vibrational frequencies and IR spectra were obtained on the basis of vibrational analysis. The result obtained by the chemometric resolution methods agreed well with that obtained by quantum chemical calculation method, which demonstrated the reliability of the proposed chemometric resolution methods. The unstable intermediate 3-amino-4-oxycyanofurazan（AOF） was confirmed via comparing the IR spectra resloved by chemometric resolution methods with those calculated by B3LYP/6-3 l＋G（d,p） and analyzed by MCR-ALS. Finally, the possible synthesis mechanism of DATF was deduced by analyzing the above IR spectra.
