The level of chemical oxygen demand(COD)is an important index to evaluate whether sewage meets the discharge requirements,so corresponding tests should be carried out before discharge.Fourier transform infrared spectr...The level of chemical oxygen demand(COD)is an important index to evaluate whether sewage meets the discharge requirements,so corresponding tests should be carried out before discharge.Fourier transform infrared spectroscopy(FTIR)and attenuated total reflectance(ATR)can detect COD in sewage effectively,which has advantages over conventional chemical analysis methods.And the selection of characteristic bands was one of the key links in the application of FTIR/ATR spectroscopy.In this work,based on the moving window partial least-squares(MWPLS)regression to select a characteristic wavelength,a method of equivalent wavelength selection was proposed combining with paired t-test equivalent concept.The results showed that the prediction effect of the selected wavelength was very close to that of the MWPLS method,while the number of wavelength points was much smaller.SEPAve,RP,Ave,SEPStd,and RP,Std which characterized the modeling effect were 26.3 mg L^-1,0.969,3.49 mg L^-1,and 0.006,respectively.The validation effect V-SEP and V-RP were 28.64 mg L^-1 and 0.960,respectively.The selected waveband was between 1809 cm^-1 and 1568 cm^-1.The method was of more reference value for the design of FTIR/ATR spectral instrument for COD detection.展开更多
目的探讨薄荷醇对皮肤角质层结构影响的作用机制。方法大鼠皮肤角质层样本和健康志愿者皮肤给予薄荷醇后,测定全衰减反射傅里叶变换红外光谱(ATR-FTIR)在皮肤角质层的变化,以确定皮肤角质层结构是否改变。结果在大鼠皮肤实验中,与对照...目的探讨薄荷醇对皮肤角质层结构影响的作用机制。方法大鼠皮肤角质层样本和健康志愿者皮肤给予薄荷醇后,测定全衰减反射傅里叶变换红外光谱(ATR-FTIR)在皮肤角质层的变化,以确定皮肤角质层结构是否改变。结果在大鼠皮肤实验中,与对照组和溶剂组相比,氮酮组大鼠角质层中的CH2对称振动(2 854 cm 1)发生了相对位移,角蛋白NH-C=O振动I峰(1 659 cm 1)及II峰(1 637 cm 1)发生了位移,NH-C=O振动I峰发生了裂峰;薄荷醇组大鼠角质层中CH2非对称振动(2 925 cm 1)、CH2对称振动(2 854 cm 1)发生相对位移。在人体皮肤试验中,与对照区和溶剂区相比,氮酮组CH2非对称振动(2 921.5 cm 1)和CH2对称振动(2 852.1 cm 1)发生了3～4个波长位移;薄荷醇组CH2非对称振动(2 922.7 cm 1)和CH2对称振动(2 853.8 cm 1)发生了3～4个波长位移。结论薄荷醇可能是通过改变角质层中脂质的构象,使角质层脂质双分子层的流动性增加、有序致密结构改变,降低皮肤屏障作用,从而使药物的透过性增加。展开更多
Comparison of the ATR-FITR spectra of nature and artificial leather shows that their feature peak positions do not overlap,By analysing their spectra and their corresponding second derivative infrared spectra we can d...Comparison of the ATR-FITR spectra of nature and artificial leather shows that their feature peak positions do not overlap,By analysing their spectra and their corresponding second derivative infrared spectra we can discriminate them easily.Analysis and discrimination of leather products by ATR-FTIR is an accurate,sensitive,quick method.展开更多
The mechanism of enhancers （methanol,chloroform,azone and thiozone） was studied in vitro in mouse stratum corneum （SC）.Attenuated total reflectance Fourier-transform infrared spectroscopy （ATR-FTIR） was applied ...The mechanism of enhancers （methanol,chloroform,azone and thiozone） was studied in vitro in mouse stratum corneum （SC）.Attenuated total reflectance Fourier-transform infrared spectroscopy （ATR-FTIR） was applied to monitor the wavenumber shifts of CH2 stretching absorbance as well as the lipid content in the SC,which were used as criteria to explain the effect of the enhancers on mouse SC.The FTIR spectra record that treatment with these four enhancers would result in significant shifts toward higher wavenumber at vasCH2 and vsCH2 and the integration areas of vasCH2 and vsCH2 decrease when treatment of methanol and choloroform.It is concluded that these four enhancers could increase the gauche conformational isomer content of lipid CH2,made the lipid in the SC a more fluid state,thus the resistance of drug transdermal delivery was reduced.展开更多
基金This work was financially supported by the Natural Science Foundation of Hainan Province(417087)the Key Research and Development Program of Hainan Province(ZDYF2018007)Research Fund for Advanced Talents of Hainan University(No.kyqd1577).
文摘The level of chemical oxygen demand(COD)is an important index to evaluate whether sewage meets the discharge requirements,so corresponding tests should be carried out before discharge.Fourier transform infrared spectroscopy(FTIR)and attenuated total reflectance(ATR)can detect COD in sewage effectively,which has advantages over conventional chemical analysis methods.And the selection of characteristic bands was one of the key links in the application of FTIR/ATR spectroscopy.In this work,based on the moving window partial least-squares(MWPLS)regression to select a characteristic wavelength,a method of equivalent wavelength selection was proposed combining with paired t-test equivalent concept.The results showed that the prediction effect of the selected wavelength was very close to that of the MWPLS method,while the number of wavelength points was much smaller.SEPAve,RP,Ave,SEPStd,and RP,Std which characterized the modeling effect were 26.3 mg L^-1,0.969,3.49 mg L^-1,and 0.006,respectively.The validation effect V-SEP and V-RP were 28.64 mg L^-1 and 0.960,respectively.The selected waveband was between 1809 cm^-1 and 1568 cm^-1.The method was of more reference value for the design of FTIR/ATR spectral instrument for COD detection.
文摘目的探讨薄荷醇对皮肤角质层结构影响的作用机制。方法大鼠皮肤角质层样本和健康志愿者皮肤给予薄荷醇后,测定全衰减反射傅里叶变换红外光谱(ATR-FTIR)在皮肤角质层的变化,以确定皮肤角质层结构是否改变。结果在大鼠皮肤实验中,与对照组和溶剂组相比,氮酮组大鼠角质层中的CH2对称振动(2 854 cm 1)发生了相对位移,角蛋白NH-C=O振动I峰(1 659 cm 1)及II峰(1 637 cm 1)发生了位移,NH-C=O振动I峰发生了裂峰;薄荷醇组大鼠角质层中CH2非对称振动(2 925 cm 1)、CH2对称振动(2 854 cm 1)发生相对位移。在人体皮肤试验中,与对照区和溶剂区相比,氮酮组CH2非对称振动(2 921.5 cm 1)和CH2对称振动(2 852.1 cm 1)发生了3～4个波长位移;薄荷醇组CH2非对称振动(2 922.7 cm 1)和CH2对称振动(2 853.8 cm 1)发生了3～4个波长位移。结论薄荷醇可能是通过改变角质层中脂质的构象,使角质层脂质双分子层的流动性增加、有序致密结构改变,降低皮肤屏障作用,从而使药物的透过性增加。
文摘Comparison of the ATR-FITR spectra of nature and artificial leather shows that their feature peak positions do not overlap,By analysing their spectra and their corresponding second derivative infrared spectra we can discriminate them easily.Analysis and discrimination of leather products by ATR-FTIR is an accurate,sensitive,quick method.
文摘The mechanism of enhancers （methanol,chloroform,azone and thiozone） was studied in vitro in mouse stratum corneum （SC）.Attenuated total reflectance Fourier-transform infrared spectroscopy （ATR-FTIR） was applied to monitor the wavenumber shifts of CH2 stretching absorbance as well as the lipid content in the SC,which were used as criteria to explain the effect of the enhancers on mouse SC.The FTIR spectra record that treatment with these four enhancers would result in significant shifts toward higher wavenumber at vasCH2 and vsCH2 and the integration areas of vasCH2 and vsCH2 decrease when treatment of methanol and choloroform.It is concluded that these four enhancers could increase the gauche conformational isomer content of lipid CH2,made the lipid in the SC a more fluid state,thus the resistance of drug transdermal delivery was reduced.
