Some problems connect ed with production of new light-weight filler type are considered for sandwich layers. Constructively, the filler is the folded structure that can be developed on a plane. This feature makes it...Some problems connect ed with production of new light-weight filler type are considered for sandwich layers. Constructively, the filler is the folded structure that can be developed on a plane. This feature makes it possible to produce the filler by isometric t ransformation of thin sheet through local bending without material stretching.Th e main difficulty is that the bending must be carried out along all lines of com plex-shaped marking-out at a time. The problem of shaping can be solved by use of the original shaping device that can be transformed in operation. The herein -presented technology of production makes it possible to fabricate parts with d eep relief using a wide gamut of different materials even as the thin-sheet met al alloys and paper.展开更多
A minimum mean-squared error （MSE） beamforming algorithm employing the optimum fractional Fourier transform （Opt-FrFT） domain second-order cyclostationarity is proposed. This method can efficiently filter out the ...A minimum mean-squared error （MSE） beamforming algorithm employing the optimum fractional Fourier transform （Opt-FrFT） domain second-order cyclostationarity is proposed. This method can efficiently filter out the compact desired chirp signal, with a consequence that the cyclically uncorrelated interferences and stationary （colored） Gaussian noise are greatly suppressed in the Opt- FrFT domain. This improves the MSE minimization cyclic beamformer by reducing effectively the Opt-FrFY domain signal-noise cross terms in the presence of finite data length de-correlation operation. Simulation results show that the new method works well under a wide range of signal-to-noise ratio （SNR） and signal-to-interference ratio （SIR）.展开更多
Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch. The character- istics of mesophase pitches were examined using polarized light optical microscopy, apparent viscome- try, Fourier...Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch. The character- istics of mesophase pitches were examined using polarized light optical microscopy, apparent viscome- try, Fourier transform infrared spectrometry, IH nuclear magnetic resonance spectrometry, and X-ray diffractometry. The properties of the mesophase pitch were greatly improved because of the eutectic effect. The soluble content increased from 5% to 56%, the mesophase itself increased from 32% to 100%, and the optical texture was changed from a coarse mosaic into a flow domain after the waste polystyrene was added to the ethylene tar pitch. The apparent viscosity showed that the mesophase pitch changed from thixotropic to Newtonian suggesting improved rheological behavior during co-carbonization）The increased number of alkyl groups, which are mainly methylene groups, altered the molecular structure of the mesophase pitch in a way that resulted in the eutectic effect.展开更多
Our previous studies had confirmed that the essential oil from Zanthoxylum bungeanum Maxim. （Z. bungeanum oil） could effectively enhance the percutaneous permeation of drug molecules as a natural transdermal penetra...Our previous studies had confirmed that the essential oil from Zanthoxylum bungeanum Maxim. （Z. bungeanum oil） could effectively enhance the percutaneous permeation of drug molecules as a natural transdermal penetration enhancer. The aim of the present study is to investigate and compare the skin penetration enhancement effect of Z. bungeanum oil and its main components on traditional Chinese medicine （TCM） active components. Toxicities of Z. bungeanum oil and three selected terpene compounds （terpinen-4-ol, 1,8-cineole, and limonene） in epidermal keratinocytes （HaCaT） and dermal flbroblast （CCC-ESF-1） cell lines were measured using an MTT （3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide） assay. Five model drugs in TCM external preparations, namely osthole （OT）, tetramethylpyrazine （TMP）, ferulic acid （FA）, puerarin （PR）, and geniposide （GP）, which were selected based on their lipophilicity denoted by IogKo^w, were tested using in vitro permeation studies in which vertical Franz diffusion ceils and rat abdominal skin were employed. The secondary structure changes of skin stratum corneum （SC） and drug thermodynamic activities were investigated to understand their mechanisms of action using Fourier transform infrared （FTIR） spectroscopy and saturation solubility studies, respectively. It was found that Z. bungeanum oil showed lower toxicities in both HaCaT cells and CCC-ESF-1 cells compared with three terpene compounds used alone. The enhancement permeation capacities by all tested agents were in the following increasing order： terpinen-4-ol=1,8-cineole〈limonene〈Z, bungeanum oil. The mechanisms of permeation enhancement suggested that these enhancers promoted the skin permeation of drugs mainly by affecting SC lipids. These results indicated that Z. bungeanum oil exhibited better performance in enhancing the skin permeation of active components in TCM preparations.展开更多
The aim of this present study is to investigate the effect of Zanthoxylum bungeanum oil （essential oil from Z. bungeanum Maxim.） on cytotoxicity and the transdermal permeation of 5-fluorouracil and indomethacin. The...The aim of this present study is to investigate the effect of Zanthoxylum bungeanum oil （essential oil from Z. bungeanum Maxim.） on cytotoxicity and the transdermal permeation of 5-fluorouracil and indomethacin. The cy- totoxicity of Z. bungeanum oil on dermal fibroblasts and epidermal keratinocytes was studied using an MTT （3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide） assay. The rat skin was employed to determine the percutaneous penetration enhancement effect of Z. bungeanum oil on hydrophilic and lipophilic model drugs, i.e., 5-fluorouracil and indomethacin. The secondary structure changes of the rat stratum comeum （SC） were determined using attenuated total reflectance-Fourier transform infrared spectroscopy （ATR-FTIR）, and saturated solubilities and SC/vehicle partition coefficients of two model drugs with and without Z. bungeanum oil were also measured to un- derstand its related mechanisms of action. It was found that the half maximal inhibitory concentration （ICs0） values of Z. bungeanum oil were significantly lower in HaCaT and CCC-ESF-1 cell lines compared to the well-established and standard penetration enhancer Azone. The Z. bungeanum oil at various concentrations effectively facilitated the percutaneous penetration of two model drugs across the rat skin. In addition, the mechanisms of permeation en- hancement by Z. bungeanum oil could be explained with saturated solubility, SC/vehicle partition coefficient, and secondary structure changes of SC.展开更多
文摘Some problems connect ed with production of new light-weight filler type are considered for sandwich layers. Constructively, the filler is the folded structure that can be developed on a plane. This feature makes it possible to produce the filler by isometric t ransformation of thin sheet through local bending without material stretching.Th e main difficulty is that the bending must be carried out along all lines of com plex-shaped marking-out at a time. The problem of shaping can be solved by use of the original shaping device that can be transformed in operation. The herein -presented technology of production makes it possible to fabricate parts with d eep relief using a wide gamut of different materials even as the thin-sheet met al alloys and paper.
基金Supported by the National Natural Science Foundation of China （ No. 60672084, 60602037, 60736006）.
文摘A minimum mean-squared error （MSE） beamforming algorithm employing the optimum fractional Fourier transform （Opt-FrFT） domain second-order cyclostationarity is proposed. This method can efficiently filter out the compact desired chirp signal, with a consequence that the cyclically uncorrelated interferences and stationary （colored） Gaussian noise are greatly suppressed in the Opt- FrFT domain. This improves the MSE minimization cyclic beamformer by reducing effectively the Opt-FrFY domain signal-noise cross terms in the presence of finite data length de-correlation operation. Simulation results show that the new method works well under a wide range of signal-to-noise ratio （SNR） and signal-to-interference ratio （SIR）.
基金the financial support by the Fundamental Research Funds for the Central Universities (No.2010QNA14)
文摘Ethylene tar pitch was co-carbonized with waste polystyrene to prepare mesophase pitch. The character- istics of mesophase pitches were examined using polarized light optical microscopy, apparent viscome- try, Fourier transform infrared spectrometry, IH nuclear magnetic resonance spectrometry, and X-ray diffractometry. The properties of the mesophase pitch were greatly improved because of the eutectic effect. The soluble content increased from 5% to 56%, the mesophase itself increased from 32% to 100%, and the optical texture was changed from a coarse mosaic into a flow domain after the waste polystyrene was added to the ethylene tar pitch. The apparent viscosity showed that the mesophase pitch changed from thixotropic to Newtonian suggesting improved rheological behavior during co-carbonization）The increased number of alkyl groups, which are mainly methylene groups, altered the molecular structure of the mesophase pitch in a way that resulted in the eutectic effect.
基金supported by the Beijing Natural Science Foundation(No.7132127)the Innovative Research Team in Beijing University of Chinese Medicine(No.2011-CXTD-13),China
文摘Our previous studies had confirmed that the essential oil from Zanthoxylum bungeanum Maxim. （Z. bungeanum oil） could effectively enhance the percutaneous permeation of drug molecules as a natural transdermal penetration enhancer. The aim of the present study is to investigate and compare the skin penetration enhancement effect of Z. bungeanum oil and its main components on traditional Chinese medicine （TCM） active components. Toxicities of Z. bungeanum oil and three selected terpene compounds （terpinen-4-ol, 1,8-cineole, and limonene） in epidermal keratinocytes （HaCaT） and dermal flbroblast （CCC-ESF-1） cell lines were measured using an MTT （3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide） assay. Five model drugs in TCM external preparations, namely osthole （OT）, tetramethylpyrazine （TMP）, ferulic acid （FA）, puerarin （PR）, and geniposide （GP）, which were selected based on their lipophilicity denoted by IogKo^w, were tested using in vitro permeation studies in which vertical Franz diffusion ceils and rat abdominal skin were employed. The secondary structure changes of skin stratum corneum （SC） and drug thermodynamic activities were investigated to understand their mechanisms of action using Fourier transform infrared （FTIR） spectroscopy and saturation solubility studies, respectively. It was found that Z. bungeanum oil showed lower toxicities in both HaCaT cells and CCC-ESF-1 cells compared with three terpene compounds used alone. The enhancement permeation capacities by all tested agents were in the following increasing order： terpinen-4-ol=1,8-cineole〈limonene〈Z, bungeanum oil. The mechanisms of permeation enhancement suggested that these enhancers promoted the skin permeation of drugs mainly by affecting SC lipids. These results indicated that Z. bungeanum oil exhibited better performance in enhancing the skin permeation of active components in TCM preparations.
基金supported by the National Natural Science Foundation of China(No.81073059)the Beijing Natural Science Foundation(No.7132127)the Innovative Research Team in Beijing University of Chinese Medicine(No.2011-CXTD-13),China
文摘The aim of this present study is to investigate the effect of Zanthoxylum bungeanum oil （essential oil from Z. bungeanum Maxim.） on cytotoxicity and the transdermal permeation of 5-fluorouracil and indomethacin. The cy- totoxicity of Z. bungeanum oil on dermal fibroblasts and epidermal keratinocytes was studied using an MTT （3-（4,5-dimethylthiazol-2-yl）-2,5-diphenyltetrazolium bromide） assay. The rat skin was employed to determine the percutaneous penetration enhancement effect of Z. bungeanum oil on hydrophilic and lipophilic model drugs, i.e., 5-fluorouracil and indomethacin. The secondary structure changes of the rat stratum comeum （SC） were determined using attenuated total reflectance-Fourier transform infrared spectroscopy （ATR-FTIR）, and saturated solubilities and SC/vehicle partition coefficients of two model drugs with and without Z. bungeanum oil were also measured to un- derstand its related mechanisms of action. It was found that the half maximal inhibitory concentration （ICs0） values of Z. bungeanum oil were significantly lower in HaCaT and CCC-ESF-1 cell lines compared to the well-established and standard penetration enhancer Azone. The Z. bungeanum oil at various concentrations effectively facilitated the percutaneous penetration of two model drugs across the rat skin. In addition, the mechanisms of permeation en- hancement by Z. bungeanum oil could be explained with saturated solubility, SC/vehicle partition coefficient, and secondary structure changes of SC.
