Lutein and lutein esters in marigold flowers was quantitatively determined by high performance chromatography （HPLC） with ODS-C 18 column.A mixture of CH3CNCD*2CH3OHCD*2CH3COOCH2CH3 with volume ratio of 55∶1∶44 wa...Lutein and lutein esters in marigold flowers was quantitatively determined by high performance chromatography （HPLC） with ODS-C 18 column.A mixture of CH3CNCD*2CH3OHCD*2CH3COOCH2CH3 with volume ratio of 55∶1∶44 was used as mobile phase at a flow rate of 1.0 mL/min and detection was carried out at 460nm. The column temperature was about 20℃. The contents of lutein and lutein esters were determined by analytical curve of lutein since lutein and lutein esters have the same spectral characteristics. Determination results of hexane extracts and saponified samples of lutein show that the saponification transforms the esters into free lutein. The increase of the content of dipalmitate and palmitate stearate reveals that the reaction includes transesterifications.展开更多
Ramanujan sums （RS） and their Fourier transforms have attracted more and more attention in signal processing in recent years. Due to their non-periodic and non-uniform spectrum, RS are widely used in low-frequency n...Ramanujan sums （RS） and their Fourier transforms have attracted more and more attention in signal processing in recent years. Due to their non-periodic and non-uniform spectrum, RS are widely used in low-frequency noise processing, Doppler spectrum estimation and time-frequency analysis. However, the traditional method for calculating RS values is rather complex since it requires two numbers＇ factorization in two arithmetic functions. For a length-n vector, its Ramanujan-Fourier transform usually involves a series of RS values which will occupy O（n2） memory units. Thus, in this paper an approach based on prime-composition is proposed to reduce the complexity of RS calculation to O（n）. Meanwhile, the complexity of Ramanujan-Fourier transform can be further reduced from O（n2） to O（n In（In（n））） .展开更多
The enzyme activities of phenylalanine ammonia-lyase from six years old Ginkgo biloba leaves in the potted orchard were induced by four groups of metal ions respectively. The PAL activities and flavonoids content were...The enzyme activities of phenylalanine ammonia-lyase from six years old Ginkgo biloba leaves in the potted orchard were induced by four groups of metal ions respectively. The PAL activities and flavonoids content were measured by the UV-Vis spectrophotometer. Changes of the whole year were also studied. The results showed that four groups of metal ion treatments had significant effects on the PAL activities and flavonoids contents in Ginkgo leaves. The treatments with 0.1% and 0.3% FeSO4, 0.1%, 0.2% and 0.3% ZnSO4, 0.1%, 0.3% and 0.5% MnSO4, 0.1% and 0.4% CuSO4 not only enhanced flavonoids contents, but also extended the optimum harvest dates of ginkgo leaves. The optimum combination was 0.1% FeSO4, 0.2% ZnSO4, 0.3% MnSO4, and 0.4% CuSO4. It could improve flavonoids content up to 1.619 4%.展开更多
Highly stable dispersions of nanosized copper （Cu） particles with an average size of （2.6 ± 0.5） nm were synthesized by in situ reduction of Cu（II） to immobilize Cu nanoparticles on the amino-enriched surfa...Highly stable dispersions of nanosized copper （Cu） particles with an average size of （2.6 ± 0.5） nm were synthesized by in situ reduction of Cu（II） to immobilize Cu nanoparticles on the amino-enriched surface of chitosan （CTS）. The synthetic process and stability of the L-ascorbic acid-stabilized Cu-CTS nanocomposites were investigated by X-ray photoelectron spectroscopy and Fourier transform Infrared spectroscopy. The antimicrobial efficiency and potency of the Cu-CTS nanocomposites were studied. The Cu-CTS nanocomposites were found to exhibit a broad antimicrobial spectrum and high antimicrobial activity against Gram-positive bacterial pathogen Staphylococcus aureus and fungal pathogen Monilia albican. The minimum inhibitory concentration of the Cu-CTS nanocomposites toward S. aureus was found to be 6.4 μg mL^-1, much lower than those reported in the literature. Furthermore, the Cu-CTS nanocomposites were stable and main- tained good disinfection potential even after 90-day shelf-time under ambient conditions.展开更多
文摘Lutein and lutein esters in marigold flowers was quantitatively determined by high performance chromatography （HPLC） with ODS-C 18 column.A mixture of CH3CNCD*2CH3OHCD*2CH3COOCH2CH3 with volume ratio of 55∶1∶44 was used as mobile phase at a flow rate of 1.0 mL/min and detection was carried out at 460nm. The column temperature was about 20℃. The contents of lutein and lutein esters were determined by analytical curve of lutein since lutein and lutein esters have the same spectral characteristics. Determination results of hexane extracts and saponified samples of lutein show that the saponification transforms the esters into free lutein. The increase of the content of dipalmitate and palmitate stearate reveals that the reaction includes transesterifications.
基金Supported by the National Natural Science Foundation of China(No.61071070)
文摘Ramanujan sums （RS） and their Fourier transforms have attracted more and more attention in signal processing in recent years. Due to their non-periodic and non-uniform spectrum, RS are widely used in low-frequency noise processing, Doppler spectrum estimation and time-frequency analysis. However, the traditional method for calculating RS values is rather complex since it requires two numbers＇ factorization in two arithmetic functions. For a length-n vector, its Ramanujan-Fourier transform usually involves a series of RS values which will occupy O（n2） memory units. Thus, in this paper an approach based on prime-composition is proposed to reduce the complexity of RS calculation to O（n）. Meanwhile, the complexity of Ramanujan-Fourier transform can be further reduced from O（n2） to O（n In（In（n））） .
基金Acknowledgments： This work was funded by the New Century Talent Support Program （No. NCET-04-0746） and the Region Technology Development Program of Chinese Ministry of Education （No. 02095）, and the Natural Science Foundation of Hubei province （No. 2002AB094）, the Youth Talent Foundation of Hubei province （No. 2003AB014） and the Educational Office Key Research Program of Hubei Province of China （No. Z200627002）.
文摘The enzyme activities of phenylalanine ammonia-lyase from six years old Ginkgo biloba leaves in the potted orchard were induced by four groups of metal ions respectively. The PAL activities and flavonoids content were measured by the UV-Vis spectrophotometer. Changes of the whole year were also studied. The results showed that four groups of metal ion treatments had significant effects on the PAL activities and flavonoids contents in Ginkgo leaves. The treatments with 0.1% and 0.3% FeSO4, 0.1%, 0.2% and 0.3% ZnSO4, 0.1%, 0.3% and 0.5% MnSO4, 0.1% and 0.4% CuSO4 not only enhanced flavonoids contents, but also extended the optimum harvest dates of ginkgo leaves. The optimum combination was 0.1% FeSO4, 0.2% ZnSO4, 0.3% MnSO4, and 0.4% CuSO4. It could improve flavonoids content up to 1.619 4%.
基金partially supported by theNational Natural Science Foundation of China(21173047 and21073036)
文摘Highly stable dispersions of nanosized copper （Cu） particles with an average size of （2.6 ± 0.5） nm were synthesized by in situ reduction of Cu（II） to immobilize Cu nanoparticles on the amino-enriched surface of chitosan （CTS）. The synthetic process and stability of the L-ascorbic acid-stabilized Cu-CTS nanocomposites were investigated by X-ray photoelectron spectroscopy and Fourier transform Infrared spectroscopy. The antimicrobial efficiency and potency of the Cu-CTS nanocomposites were studied. The Cu-CTS nanocomposites were found to exhibit a broad antimicrobial spectrum and high antimicrobial activity against Gram-positive bacterial pathogen Staphylococcus aureus and fungal pathogen Monilia albican. The minimum inhibitory concentration of the Cu-CTS nanocomposites toward S. aureus was found to be 6.4 μg mL^-1, much lower than those reported in the literature. Furthermore, the Cu-CTS nanocomposites were stable and main- tained good disinfection potential even after 90-day shelf-time under ambient conditions.
