A new orbit of Triton was provided by our previous work, benefitted by new Gaia Data, both in a new precise reduction of charge-coupled device observations and in the planetary ephemeris INPOP19 a.In this paper, we pr...A new orbit of Triton was provided by our previous work, benefitted by new Gaia Data, both in a new precise reduction of charge-coupled device observations and in the planetary ephemeris INPOP19 a.In this paper, we provide a new ephemeris for another main Neptunian satellite, Nereid. The orbit is fitted for the newest observations, including 2 075 ground-based observations during the period 1949-2018 and 83 space observations acquired by the Voyager 2 spacecraft in 1989. The dynamical model used here is consistent with that of our previous work. For the ground-based absolute observations of Nereid, the rootmean-square deviations are 0.201′′in right ascension and 0.189′′in declination. Finally, a comparison with the HORIZONS ephemeris is made and discussed.展开更多
Adaptation of microbial communities to anthropogenic stress has often been shown to involve reduction in diversity and in selective enrichment of species capable of survival. The gut bacterial community of pollution-s...Adaptation of microbial communities to anthropogenic stress has often been shown to involve reduction in diversity and in selective enrichment of species capable of survival. The gut bacterial community of pollution-stressed polychaete Neanthes chilkaensis was studied using cultivation dependent and independent approaches. The possible role of the gut bacteria in remediation of pollutants was also studied. The analysis of clones covering about 90% of the 16S rRNA clone library indicated that the majority of the taxa in the library resemble GenBank entries of aromatic- hydrocarbon pollutant degraders. Among them Firmicutes and Actinobacteria were dominant. About 84% of the gut isolates were capable of utilizing PAHs as sole carbon sources while 20% of isolates were found to produce biosurfactants. Production of surfactant along with capability to utilize PAH and other pollutants indicate the role of the gut community in alleviating the pollution stress. The results also show the potential source of microorganisms with industrial and environmental application.展开更多
目的:测定不同品种沙蚕中15种氨基酸含量并进行多元统计分析。方法:采用酸水解法制备水解氨基酸样品溶液,以异硫氰酸苯酯为衍生化试剂衍生后进行HPLC分析。采用CAPCELL PAK C18色谱柱(4.6 mm×250 mm,5μm),以0.1 mol·L^(-1)...目的:测定不同品种沙蚕中15种氨基酸含量并进行多元统计分析。方法:采用酸水解法制备水解氨基酸样品溶液,以异硫氰酸苯酯为衍生化试剂衍生后进行HPLC分析。采用CAPCELL PAK C18色谱柱(4.6 mm×250 mm,5μm),以0.1 mol·L^(-1)醋酸钠溶液(p H 6.5)-乙腈(93∶7)为流动相A,乙腈-水(8∶2)为流动相B,梯度洗脱,流速1.0 m L·min^(-1),柱温40℃,检测波长254 nm,进样量2μL。采用主成分分析法对不同品种沙蚕中15种氨基酸相对含量进行分析。结果:15种氨基酸在一定浓度范围内呈良好线性关系,线性相关系数r值均大于0.999 6,加样回收率(n=6)为96.1%~101.5%,氨基酸衍生溶液在12 h内稳定;氨基酸相对含量的主成分分析可以达到降维的目的,各品种沙蚕样品得到较好的区分。结论:所建立的条件方法可靠,精密度和重复性良好,可用于沙蚕中水解氨基酸含量的测定,主成分分析可用于揭示沙蚕的特征氨基酸,为沙蚕品质特征评价提供依据。展开更多
基金funded by the B-type Strategic Priority Program of the Chinese Academy of Sciences(Grant No.XDB41000000)the National Natural Science Foundation of China(NSFC)under Nos.12073062 and 11803019the Preresearch Project on Civil Aerospace Technologies funded by the China National Space Administration(Grant No.D020303)。
文摘A new orbit of Triton was provided by our previous work, benefitted by new Gaia Data, both in a new precise reduction of charge-coupled device observations and in the planetary ephemeris INPOP19 a.In this paper, we provide a new ephemeris for another main Neptunian satellite, Nereid. The orbit is fitted for the newest observations, including 2 075 ground-based observations during the period 1949-2018 and 83 space observations acquired by the Voyager 2 spacecraft in 1989. The dynamical model used here is consistent with that of our previous work. For the ground-based absolute observations of Nereid, the rootmean-square deviations are 0.201′′in right ascension and 0.189′′in declination. Finally, a comparison with the HORIZONS ephemeris is made and discussed.
文摘Adaptation of microbial communities to anthropogenic stress has often been shown to involve reduction in diversity and in selective enrichment of species capable of survival. The gut bacterial community of pollution-stressed polychaete Neanthes chilkaensis was studied using cultivation dependent and independent approaches. The possible role of the gut bacteria in remediation of pollutants was also studied. The analysis of clones covering about 90% of the 16S rRNA clone library indicated that the majority of the taxa in the library resemble GenBank entries of aromatic- hydrocarbon pollutant degraders. Among them Firmicutes and Actinobacteria were dominant. About 84% of the gut isolates were capable of utilizing PAHs as sole carbon sources while 20% of isolates were found to produce biosurfactants. Production of surfactant along with capability to utilize PAH and other pollutants indicate the role of the gut community in alleviating the pollution stress. The results also show the potential source of microorganisms with industrial and environmental application.
文摘目的:测定不同品种沙蚕中15种氨基酸含量并进行多元统计分析。方法:采用酸水解法制备水解氨基酸样品溶液,以异硫氰酸苯酯为衍生化试剂衍生后进行HPLC分析。采用CAPCELL PAK C18色谱柱(4.6 mm×250 mm,5μm),以0.1 mol·L^(-1)醋酸钠溶液(p H 6.5)-乙腈(93∶7)为流动相A,乙腈-水(8∶2)为流动相B,梯度洗脱,流速1.0 m L·min^(-1),柱温40℃,检测波长254 nm,进样量2μL。采用主成分分析法对不同品种沙蚕中15种氨基酸相对含量进行分析。结果:15种氨基酸在一定浓度范围内呈良好线性关系,线性相关系数r值均大于0.999 6,加样回收率(n=6)为96.1%~101.5%,氨基酸衍生溶液在12 h内稳定;氨基酸相对含量的主成分分析可以达到降维的目的,各品种沙蚕样品得到较好的区分。结论:所建立的条件方法可靠,精密度和重复性良好,可用于沙蚕中水解氨基酸含量的测定,主成分分析可用于揭示沙蚕的特征氨基酸,为沙蚕品质特征评价提供依据。
