Ultrafast time_resolved fluorescence experiments have been performed with core antennas CP43 and CP47 of PS Ⅱ. Their dynamic fluorescence spectra were obtained with excitation wavelength 514.5 nm. For CP43, the emiss...Ultrafast time_resolved fluorescence experiments have been performed with core antennas CP43 and CP47 of PS Ⅱ. Their dynamic fluorescence spectra were obtained with excitation wavelength 514.5 nm. For CP43, the emission spectrum was found to be from 640 to 780 nm with a peak at ～680 nm and the lifetime of fluorescence was 3.54 ns. For CP47, the emission spectrum was from 630 to 775 nm with a peak at ～691 nm and the fluorescence lifetime was 3.22 ns. The fluorescence emission efficiencies of Chl a in CP43 and CP47 were calculated to be approximately 38.3% and 40.6%, respectively. The energy transfer from β_Car to Chl a in CP43 and CP47 was discussed. The rates of energy transfer from β_Car to Chl a were measured to be about 9.6×10 11 s -1 and 1.3×10 12 s -1 and energy transfer efficiencies 47.5% and 66.5% respectively. The edge_edge distances between β_Car and Chl a in CP43 and CP47 were estimated to be ～0.110 nm and ～0.085 nm respectively.展开更多
A phytosociological study of a weed community dominated by Hydrocotyle mannii and Centella asiatica was carried out in Kampala, the capital city of Uganda from 2000 to 2002. The Zurich-Montpellier School of Phytosocio...A phytosociological study of a weed community dominated by Hydrocotyle mannii and Centella asiatica was carried out in Kampala, the capital city of Uganda from 2000 to 2002. The Zurich-Montpellier School of Phytosociology method was used with special emphasis on floristic and synecological structure as well as on dynamic aspects. This community was found to grow on shady moist roadsides and is about 15 cm high. In total, 54 species were recorded; most of them are annual, anemochorous and widespread. The Hydrocotyle mannii and Centella asiatica community is described as a new weed association： Hydocotylo-Centelletum asiaticae Mosango ass. nova.. Hydrocotyle mannii, Centella asiatica, Dichondra repens and Sida veronicifolia have been recognized as the character species of this association. The Hydrocotylo-Centelletum is a pioneer association. It has been ascribed to the alliance Eleusinion indicae Leonard 1950 which includes plant communities growing on shady roadsides. In terms of ecological succession, it appears to be evolving to the Asystasia gangetica herbaceous fallow association which belongs to the alliance Panicion maximi. It belongs to the order Ruderali-Euphorbietalia Schmitz 1971 and the class Ruderali-Manihotetea Leonard in Taton 1949.展开更多
This research aimed at the use of natural products to extend the shelf life of perishable vegetables. Studies were conducted on the preservative effects of four plant extracts--Xylopia aethiopica, Piper nigrum, Tetrap...This research aimed at the use of natural products to extend the shelf life of perishable vegetables. Studies were conducted on the preservative effects of four plant extracts--Xylopia aethiopica, Piper nigrum, Tetrapleura tetraptera and Carica papaya seeds on tomato and pepper. Tomato and pepper were dipped into four different concentrations of aqueous extracts of the four plants as well as water serving as control. The result of the study showed that aqueous extract of all plants extended the shelf life of tomato and pepper with increasing concentration of the extracts, except for Carica papaya seeds which produced significant elongation of 12.0 ±0.6 d and 14.0 ± 0.7 d on tomato and pepper, respectively, at the least concentration of 0.25 mg/mL. The results showed that these ethnomedicinal plants can serve as good and potent sources of natural preservatives which can be used to substitute existing synthetics used in the food industry.展开更多
Waldorf Astoria Beijing’s new tea time treats make it all better as temperatures soar.When it seems hotter than ever and the hustle and bustle of city life is making you blue,escape to the cool comfort and elegant su...Waldorf Astoria Beijing’s new tea time treats make it all better as temperatures soar.When it seems hotter than ever and the hustle and bustle of city life is making you blue,escape to the cool comfort and elegant surroundings of Peacock Alley.展开更多
文摘Ultrafast time_resolved fluorescence experiments have been performed with core antennas CP43 and CP47 of PS Ⅱ. Their dynamic fluorescence spectra were obtained with excitation wavelength 514.5 nm. For CP43, the emission spectrum was found to be from 640 to 780 nm with a peak at ～680 nm and the lifetime of fluorescence was 3.54 ns. For CP47, the emission spectrum was from 630 to 775 nm with a peak at ～691 nm and the fluorescence lifetime was 3.22 ns. The fluorescence emission efficiencies of Chl a in CP43 and CP47 were calculated to be approximately 38.3% and 40.6%, respectively. The energy transfer from β_Car to Chl a in CP43 and CP47 was discussed. The rates of energy transfer from β_Car to Chl a were measured to be about 9.6×10 11 s -1 and 1.3×10 12 s -1 and energy transfer efficiencies 47.5% and 66.5% respectively. The edge_edge distances between β_Car and Chl a in CP43 and CP47 were estimated to be ～0.110 nm and ～0.085 nm respectively.
文摘A phytosociological study of a weed community dominated by Hydrocotyle mannii and Centella asiatica was carried out in Kampala, the capital city of Uganda from 2000 to 2002. The Zurich-Montpellier School of Phytosociology method was used with special emphasis on floristic and synecological structure as well as on dynamic aspects. This community was found to grow on shady moist roadsides and is about 15 cm high. In total, 54 species were recorded; most of them are annual, anemochorous and widespread. The Hydrocotyle mannii and Centella asiatica community is described as a new weed association： Hydocotylo-Centelletum asiaticae Mosango ass. nova.. Hydrocotyle mannii, Centella asiatica, Dichondra repens and Sida veronicifolia have been recognized as the character species of this association. The Hydrocotylo-Centelletum is a pioneer association. It has been ascribed to the alliance Eleusinion indicae Leonard 1950 which includes plant communities growing on shady roadsides. In terms of ecological succession, it appears to be evolving to the Asystasia gangetica herbaceous fallow association which belongs to the alliance Panicion maximi. It belongs to the order Ruderali-Euphorbietalia Schmitz 1971 and the class Ruderali-Manihotetea Leonard in Taton 1949.
文摘This research aimed at the use of natural products to extend the shelf life of perishable vegetables. Studies were conducted on the preservative effects of four plant extracts--Xylopia aethiopica, Piper nigrum, Tetrapleura tetraptera and Carica papaya seeds on tomato and pepper. Tomato and pepper were dipped into four different concentrations of aqueous extracts of the four plants as well as water serving as control. The result of the study showed that aqueous extract of all plants extended the shelf life of tomato and pepper with increasing concentration of the extracts, except for Carica papaya seeds which produced significant elongation of 12.0 ±0.6 d and 14.0 ± 0.7 d on tomato and pepper, respectively, at the least concentration of 0.25 mg/mL. The results showed that these ethnomedicinal plants can serve as good and potent sources of natural preservatives which can be used to substitute existing synthetics used in the food industry.
文摘Waldorf Astoria Beijing’s new tea time treats make it all better as temperatures soar.When it seems hotter than ever and the hustle and bustle of city life is making you blue,escape to the cool comfort and elegant surroundings of Peacock Alley.
