UV-curable hyperbranched polyurethane acrylate-polyurethane diacrylate/SiO2 dispersion(HBPUA-PUDA/SiO2) was prepared with isophorone diisocyanate(IPDI),hyperbranched polyester Boltorn H20(H20),hydroxy-ethyl acrylate(H...UV-curable hyperbranched polyurethane acrylate-polyurethane diacrylate/SiO2 dispersion(HBPUA-PUDA/SiO2) was prepared with isophorone diisocyanate(IPDI),hyperbranched polyester Boltorn H20(H20),hydroxy-ethyl acrylate(HEA),polyethyleneglycol(PEG-200) and nano-SiO2.The UV curing kinetics of the films was investigated by FTIR.The results show that the curing speed of the films increases with the adding of nano-SiO2 and decreases with the adding of PUDA due to the slower chain movement.The thermal stability of the HBPUA-PUDA/SiO2 films was studied by using thermogravimetric analysis coupled with Fourier transform infrared spectroscopy(TGA/FTIR).The results show that all films exhibit two degradation stages located at about 320 and 440 °C corresponding to the degradation for hard segments of urethane-acrylate and the degradation for soft segment and polyester core.In addition,the results from the analysis of TGA/FTIR also indicate that the decomposition temperature of HBPUA-PUDA/SiO2 film is 15 °C higher than that obtained for pure polymer.The degradation mechanism was proposed according to TGA/FTIR results.展开更多
Copper ions(e.g.,Cu^(2+)) have outstanding antibacterial properties,but the exact mechanism is rather complex and not fully understood.In this work,synchrotron Fourier transform infrared(FTIR) spectroscopy was used as...Copper ions(e.g.,Cu^(2+)) have outstanding antibacterial properties,but the exact mechanism is rather complex and not fully understood.In this work,synchrotron Fourier transform infrared(FTIR) spectroscopy was used as an analytical tool to investigate the CuCl_2-induced biochemical changes in Escherichia coli.Our spectral measurements indicated that this technique is sensitive enough to detect changes in membrane lipids,nucleic acids,peptidoglycans and proteins of Cu^(2+)-treated bacteria.Interestingly,for short-time treated cells,the effects on phospholipid composition were clearly shown,while no significant alterations of proteins,nucleic acids and peptidoglycans were found.PeakForce quantitative nano-mechanics mode atomic force microscopy(AFM)confirmed the changes in the topography and mechanical properties of bacteria upon the Cu^(2+) exposure.This study demonstrated that FTIR spectroscopy combined with AFM can provide more comprehensive evaluation on the biochemical and mechanical responses of bacteria to copper.展开更多
It has been generally unclear over the mechanism of inhibitory influence of silicate on structural rearrangement or solely physical adsorption onto manganese dioxide(MnO_2) about the decomposition of hydrogen peroxide...It has been generally unclear over the mechanism of inhibitory influence of silicate on structural rearrangement or solely physical adsorption onto manganese dioxide(MnO_2) about the decomposition of hydrogen peroxide(H_2O_2). Consequently,several experiments were carried out by using MnO_2 as a catalyst for the decomposition of H_2O_2 in a concentration series under certain concentrations of silicates. The silicates were analyzed by using a molybdenum blue colorimetric method. The results showed that the determination of silicates was inhibited by H_2O_2, whose inhibitory effect was greatly increased by increasing its concentration, but not limited by p H. SEM-EDX(scanning electron microscopy-energy dispersive x-ray spectrometry) results showed that the adsorption of silicates onto the surface of MnO_2 was not purely via a structural rearrangement, with increasing Mn atoms protruding on the outer surface by covering oxygen and silicon atoms. XRD(X-ray diffraction) and FTIR(Fourier transform infrared) spectra results further revealed no significant total crystal structural changes in MnO_2 after the adsorption of silicates, but only a small shift of 0.21° at 2θ from 56.36° to 56.15°, and a FTIR vibration showed at around 1 050 cm-1. The results, therefore, showed that silicate adsorption onto MnO_2 took place via both surface adsorption and structural rearrangement by interfacial reaction.展开更多
In plant cells the plasma membrane is a highly elaborated structure that functions as the point of exchange with adjoining cells, cell walls and the external environment. In this study, we investigated the structure a...In plant cells the plasma membrane is a highly elaborated structure that functions as the point of exchange with adjoining cells, cell walls and the external environment. In this study, we investigated the structure and function characteristic of wheat root plasma membrane (PM) as affected by H2O2 and Fe by using fluorescence spectroscopic and attenuated total reflectance infrared (ATR-IR) techniques. The results showed that these oxidant damaged induced an obviously reduced membrane fluidity were observed in the roots PM treated with the 200 μM H2O2, FeSO4, and FeCl3. Computer-aided software analyses of the FTIR spectrum indicated that the content of the α-helices decreased and β-sheet increased in the secondary structures of proteins after exposure to the oxidants of 200 μM H2O2, FeSO4, and FeCl3. The number of P=O and C=C bonds area declined rapidly in the lipids of the membrane under the oxidants stress. These structural alterations might explain the reason of the roots PM instability under most of the abiotic stress.展开更多
文摘UV-curable hyperbranched polyurethane acrylate-polyurethane diacrylate/SiO2 dispersion(HBPUA-PUDA/SiO2) was prepared with isophorone diisocyanate(IPDI),hyperbranched polyester Boltorn H20(H20),hydroxy-ethyl acrylate(HEA),polyethyleneglycol(PEG-200) and nano-SiO2.The UV curing kinetics of the films was investigated by FTIR.The results show that the curing speed of the films increases with the adding of nano-SiO2 and decreases with the adding of PUDA due to the slower chain movement.The thermal stability of the HBPUA-PUDA/SiO2 films was studied by using thermogravimetric analysis coupled with Fourier transform infrared spectroscopy(TGA/FTIR).The results show that all films exhibit two degradation stages located at about 320 and 440 °C corresponding to the degradation for hard segments of urethane-acrylate and the degradation for soft segment and polyester core.In addition,the results from the analysis of TGA/FTIR also indicate that the decomposition temperature of HBPUA-PUDA/SiO2 film is 15 °C higher than that obtained for pure polymer.The degradation mechanism was proposed according to TGA/FTIR results.
基金Supported by National Natural Science Foundation of China(No.11474298)Shanghai Pujiang Program(No.13PJ1410500)+1 种基金Special Funds for Enterprise Independent Innovation of Shanghai(CXY-2013-58)Hundred Talents Program of the Chinese Academy Sciences
文摘Copper ions(e.g.,Cu^(2+)) have outstanding antibacterial properties,but the exact mechanism is rather complex and not fully understood.In this work,synchrotron Fourier transform infrared(FTIR) spectroscopy was used as an analytical tool to investigate the CuCl_2-induced biochemical changes in Escherichia coli.Our spectral measurements indicated that this technique is sensitive enough to detect changes in membrane lipids,nucleic acids,peptidoglycans and proteins of Cu^(2+)-treated bacteria.Interestingly,for short-time treated cells,the effects on phospholipid composition were clearly shown,while no significant alterations of proteins,nucleic acids and peptidoglycans were found.PeakForce quantitative nano-mechanics mode atomic force microscopy(AFM)confirmed the changes in the topography and mechanical properties of bacteria upon the Cu^(2+) exposure.This study demonstrated that FTIR spectroscopy combined with AFM can provide more comprehensive evaluation on the biochemical and mechanical responses of bacteria to copper.
基金Supported by the Provincial Basic Research Program of Hebei Education Department(ZD2015110)the National Special Project on Key Technologies and Demonstration of Wetland Ecological Restoration in the Haihe River Basin(2014ZX07203008)
文摘It has been generally unclear over the mechanism of inhibitory influence of silicate on structural rearrangement or solely physical adsorption onto manganese dioxide(MnO_2) about the decomposition of hydrogen peroxide(H_2O_2). Consequently,several experiments were carried out by using MnO_2 as a catalyst for the decomposition of H_2O_2 in a concentration series under certain concentrations of silicates. The silicates were analyzed by using a molybdenum blue colorimetric method. The results showed that the determination of silicates was inhibited by H_2O_2, whose inhibitory effect was greatly increased by increasing its concentration, but not limited by p H. SEM-EDX(scanning electron microscopy-energy dispersive x-ray spectrometry) results showed that the adsorption of silicates onto the surface of MnO_2 was not purely via a structural rearrangement, with increasing Mn atoms protruding on the outer surface by covering oxygen and silicon atoms. XRD(X-ray diffraction) and FTIR(Fourier transform infrared) spectra results further revealed no significant total crystal structural changes in MnO_2 after the adsorption of silicates, but only a small shift of 0.21° at 2θ from 56.36° to 56.15°, and a FTIR vibration showed at around 1 050 cm-1. The results, therefore, showed that silicate adsorption onto MnO_2 took place via both surface adsorption and structural rearrangement by interfacial reaction.
文摘In plant cells the plasma membrane is a highly elaborated structure that functions as the point of exchange with adjoining cells, cell walls and the external environment. In this study, we investigated the structure and function characteristic of wheat root plasma membrane (PM) as affected by H2O2 and Fe by using fluorescence spectroscopic and attenuated total reflectance infrared (ATR-IR) techniques. The results showed that these oxidant damaged induced an obviously reduced membrane fluidity were observed in the roots PM treated with the 200 μM H2O2, FeSO4, and FeCl3. Computer-aided software analyses of the FTIR spectrum indicated that the content of the α-helices decreased and β-sheet increased in the secondary structures of proteins after exposure to the oxidants of 200 μM H2O2, FeSO4, and FeCl3. The number of P=O and C=C bonds area declined rapidly in the lipids of the membrane under the oxidants stress. These structural alterations might explain the reason of the roots PM instability under most of the abiotic stress.
