In culturing early mouse embryos in vitro,liquid paraffin and alcohol exert deleterious influence on the development of embryos. Some of light liquid paraffin produced by Chinese factories have proved harmful for earl...In culturing early mouse embryos in vitro,liquid paraffin and alcohol exert deleterious influence on the development of embryos. Some of light liquid paraffin produced by Chinese factories have proved harmful for early mouse embryos. As shown by our experiments, the nitronaphthalene contained and the specific gravity of liquid paraffin were not involved in the injurious effects.However,alcohol mingled in medium had harmful effects on the development of embryos. At the 0.1% concentration of alcohol in medium the proportion of embryos developing to blastocysts decreased to 73.9%. When the concentration of alcohol was increased to 0.8%, all embryos ceased developing. In our experiments, CO_2 which contained 0.13% alcohol had no visible effects on the development of embrvos in vitro.展开更多
Octacosanol is purified by agitated short-path distillation (SPD). Effects of evaporation temperature,number of SPD steps in series and other distillation method on the octacosanol recovery and decomposition are studi...Octacosanol is purified by agitated short-path distillation (SPD). Effects of evaporation temperature,number of SPD steps in series and other distillation method on the octacosanol recovery and decomposition are studied. Although the experimental results indicate some decomposition when the mixture of higher primary aliphatic alcohols is distillated by SPD, SPD is still an effective method to purify octacosanol. It is concluded that evaporation temperature affects greatly on the purity and recovery of octacosanol.展开更多
In this study, phylogenetic relationships of 33 species belonging to 19 genera of Issidae and 1 outgroup (Paravarcia decapterix) were analyzed using maximum parsimony (MP) and Bayesian inference (BI) methods bas...In this study, phylogenetic relationships of 33 species belonging to 19 genera of Issidae and 1 outgroup (Paravarcia decapterix) were analyzed using maximum parsimony (MP) and Bayesian inference (BI) methods based on partial sequences of the nuclear 18S rDNA and wingless genes (Wg). The topologies of the phylogenetic trees generated from different methods were quite similar. The phylogenetic analysis divided Issidae into five subfamilies: Caliscelinae, Tonginae, Parahiraciinae, Hemisphaeriinae and Issinae. The results also supported that the genus Eusudasina should be transferred from Issinae to Hemisphaeriinae.展开更多
This study was conducted to resolve the problems of water conservation of sandy soil in desertification areas. The surface of soil particles was modified by molecules of natural Japanese wax through some specially scr...This study was conducted to resolve the problems of water conservation of sandy soil in desertification areas. The surface of soil particles was modified by molecules of natural Japanese wax through some specially screened surfactant. The modified particles were then well sprayed onto the sand, which was placed in an artificial climate box with simulating desert environment, to form a soil film with effect of suppressing water and gas-permeability. Structure of soil film was analyzed by means of X-ray diftYaction (XRD) and infrared spectrometry (IR). And its mechanism of water inhibition was illustrated with DSC and TG curves. Its influence on grass-planting was tested through the instruments of water detector. The results show that sorbitol anhydride stearate ( Span 80) could well disperse the Japanese wax and make it combine with the clay which is also dispersed. The pores among soil particles grew smaller and turned from hydrophilic into hydrophobic, in which way resistance to water penetrating through the film was increased. Experimental grass grows normally on sandy soil with the soil film in the artificial desert climate box, indicating that the soil particles modified with Japanese wax is an effective method to inhibit water evaporation.展开更多
The forewing base structure of a representative species from 13 families of Fulgoroidea were examined.Results show that these families differ mainly from the characters of various sclerites,the presence or absence of ...The forewing base structure of a representative species from 13 families of Fulgoroidea were examined.Results show that these families differ mainly from the characters of various sclerites,the presence or absence of humeral plate,proximal and distal median plate,and the method of connection between each sclerite.The phylogenetic relationships based on forewing structure support the monophyly of Fulgoroidea.Ricaniidae and Flatidae were recovered as sister taxa.Kinnaridae is the most primitive family in Fulgoroidea.展开更多
Marine microorganisms are a new source of natural antifouling compounds. In this study, two bacterial strains, Kytococcus sedentarius QDG-B506 and Bacillus cereus QDG-B509, were isolated from a marine biofilm and iden...Marine microorganisms are a new source of natural antifouling compounds. In this study, two bacterial strains, Kytococcus sedentarius QDG-B506 and Bacillus cereus QDG-B509, were isolated from a marine biofilm and identified. The bacteria fermentation broth could exert inhibitory effects on the growth of Skeletonema costatum and barnacle larvae. A procedure was employed to extract and identify the antifouling compounds. Firstly, a toxicity test was conducted by graduated pH and liquid-liquid extraction to determine the optimal extraction conditions. The best extraction conditions were found to be pH 2 and 100% petroleum ether. The EC50 value of the crude extract of K. sedentarius against the test microalgae was 236.7 ± 14.08 μg mL-1, and that of B. cereus was 290.6 ± 27.11 μg mL-1. Secondly, HLB SPE columns were used to purify the two crude extracts. After purification, the antifouling activities of the two extracts significantly increased: the EC50 of the K. sedentarius extract against the test microalgae was 86.4 ± 3.71 μg mL-1, and that of B. cereus was 92.6 ± 1.47 μg mL-1. These results suggest that the metabolites produced by the two bacterial strains are with high antifouling activities and they should be fatty acid compounds. Lastly, GC-MS was used for the structural elucidation of the compounds. The results show that the antifouling compounds produced by the two bacterial strains are myristic, palmitic and octadecanoic acids.展开更多
文摘In culturing early mouse embryos in vitro,liquid paraffin and alcohol exert deleterious influence on the development of embryos. Some of light liquid paraffin produced by Chinese factories have proved harmful for early mouse embryos. As shown by our experiments, the nitronaphthalene contained and the specific gravity of liquid paraffin were not involved in the injurious effects.However,alcohol mingled in medium had harmful effects on the development of embryos. At the 0.1% concentration of alcohol in medium the proportion of embryos developing to blastocysts decreased to 73.9%. When the concentration of alcohol was increased to 0.8%, all embryos ceased developing. In our experiments, CO_2 which contained 0.13% alcohol had no visible effects on the development of embrvos in vitro.
基金Supported by the National Natural Science Foundation of China(No. 20176037), and the Development Foundation from the Science & Technology Commission of Tianjin, China (No. 01310864).
文摘Octacosanol is purified by agitated short-path distillation (SPD). Effects of evaporation temperature,number of SPD steps in series and other distillation method on the octacosanol recovery and decomposition are studied. Although the experimental results indicate some decomposition when the mixture of higher primary aliphatic alcohols is distillated by SPD, SPD is still an effective method to purify octacosanol. It is concluded that evaporation temperature affects greatly on the purity and recovery of octacosanol.
基金supported by the National Natural Science Foundation of China(31372234,30970388)the Ministry of Education of China(TS2011XBNL061)Fauna Sinica(2006FY120100)under the Ministry of Science and Technology of China
文摘In this study, phylogenetic relationships of 33 species belonging to 19 genera of Issidae and 1 outgroup (Paravarcia decapterix) were analyzed using maximum parsimony (MP) and Bayesian inference (BI) methods based on partial sequences of the nuclear 18S rDNA and wingless genes (Wg). The topologies of the phylogenetic trees generated from different methods were quite similar. The phylogenetic analysis divided Issidae into five subfamilies: Caliscelinae, Tonginae, Parahiraciinae, Hemisphaeriinae and Issinae. The results also supported that the genus Eusudasina should be transferred from Issinae to Hemisphaeriinae.
基金supported by the Key (Key grant) Project of Chinese Ministry of Education (No. 106086)
文摘This study was conducted to resolve the problems of water conservation of sandy soil in desertification areas. The surface of soil particles was modified by molecules of natural Japanese wax through some specially screened surfactant. The modified particles were then well sprayed onto the sand, which was placed in an artificial climate box with simulating desert environment, to form a soil film with effect of suppressing water and gas-permeability. Structure of soil film was analyzed by means of X-ray diftYaction (XRD) and infrared spectrometry (IR). And its mechanism of water inhibition was illustrated with DSC and TG curves. Its influence on grass-planting was tested through the instruments of water detector. The results show that sorbitol anhydride stearate ( Span 80) could well disperse the Japanese wax and make it combine with the clay which is also dispersed. The pores among soil particles grew smaller and turned from hydrophilic into hydrophobic, in which way resistance to water penetrating through the film was increased. Experimental grass grows normally on sandy soil with the soil film in the artificial desert climate box, indicating that the soil particles modified with Japanese wax is an effective method to inhibit water evaporation.
基金supported by the National Natural Science Foundation of China(32170475,31750002)。
文摘The forewing base structure of a representative species from 13 families of Fulgoroidea were examined.Results show that these families differ mainly from the characters of various sclerites,the presence or absence of humeral plate,proximal and distal median plate,and the method of connection between each sclerite.The phylogenetic relationships based on forewing structure support the monophyly of Fulgoroidea.Ricaniidae and Flatidae were recovered as sister taxa.Kinnaridae is the most primitive family in Fulgoroidea.
基金supported by the National Basic Research Program of China (973 program, No. 2010CB735806)
文摘Marine microorganisms are a new source of natural antifouling compounds. In this study, two bacterial strains, Kytococcus sedentarius QDG-B506 and Bacillus cereus QDG-B509, were isolated from a marine biofilm and identified. The bacteria fermentation broth could exert inhibitory effects on the growth of Skeletonema costatum and barnacle larvae. A procedure was employed to extract and identify the antifouling compounds. Firstly, a toxicity test was conducted by graduated pH and liquid-liquid extraction to determine the optimal extraction conditions. The best extraction conditions were found to be pH 2 and 100% petroleum ether. The EC50 value of the crude extract of K. sedentarius against the test microalgae was 236.7 ± 14.08 μg mL-1, and that of B. cereus was 290.6 ± 27.11 μg mL-1. Secondly, HLB SPE columns were used to purify the two crude extracts. After purification, the antifouling activities of the two extracts significantly increased: the EC50 of the K. sedentarius extract against the test microalgae was 86.4 ± 3.71 μg mL-1, and that of B. cereus was 92.6 ± 1.47 μg mL-1. These results suggest that the metabolites produced by the two bacterial strains are with high antifouling activities and they should be fatty acid compounds. Lastly, GC-MS was used for the structural elucidation of the compounds. The results show that the antifouling compounds produced by the two bacterial strains are myristic, palmitic and octadecanoic acids.