CoCu/TiO_2 catalysts promoted using alkali metals（Li, Na, K, Rb, and Cs） were prepared by the homogeneous deposition-precipitation method followed by the incipient wetness impregnation method. The influences of the ...CoCu/TiO_2 catalysts promoted using alkali metals（Li, Na, K, Rb, and Cs） were prepared by the homogeneous deposition-precipitation method followed by the incipient wetness impregnation method. The influences of the alkali metals on the physicochemical properties of the CoCu/TiO_2 catalysts and the catalytic performance for CO_2 hydrogenation to long-chain hydrocarbons（C_（5＋））were investigated in this work. According to the characterization of the catalysts based on X-ray photoelectron spectroscopy, X-ray diffraction, CO_2 temperature-programmed desorption（TPD）, and H_2-TPD, the introduction of alkali metals could increase the CO_2 adsorption and decrease the H_2 chemisorption, which could suppress the formation of CH_4, enhance the production of C_（5＋）, and decrease the hydrogenation activity. Among all the promoters, the Na-modified CoCu/TiO_2 catalyst provided the maximum C_（5＋） yield of 5.4%, with a CO_2 conversion of 18.4% and C_（5＋） selectivity of42.1%, because it showed the strongest basicity and a slight decrease in the amount of H_2 desorption;it also exhibited excellent catalytic stability of more than 200 h.展开更多
Huanglongbing （HLB） is the most destructive disease of citrus worldwide. The Asian citrus psyllid, Diaphorina citri Kuwayama （Hemiptera： Psyllidae）, is the vector of the phloem-inhabiting bacterium, Candidatus Li...Huanglongbing （HLB） is the most destructive disease of citrus worldwide. The Asian citrus psyllid, Diaphorina citri Kuwayama （Hemiptera： Psyllidae）, is the vector of the phloem-inhabiting bacterium, Candidatus Liberibacter asiaticus, which is presumed to cause HLB in Florida citrus. Laboratory and field studies were conducted to examine the behavioral responses of male and female D. cirri to their cuticular extracts. In olfactometer assays, more male D. citri were attracted to one, five, or 10 female cuticular extract equivalent units than blank controls. The results were confirmed in field studies in which clear or yellow traps baited with 10 female cuticular extract equivalent units attracted proportionately more males than clear traps baited with male cuticular extract or unbaited traps. Analyses of cuticular constituents of male and female D. citri revealed differences between the sexes in chemical composition of their cuticular extracts. Laboratory bioassays with synthetic chemicals identified from cuticular extracts indicated that dodecanoic acid attracted more males than clean air. Traps baited with dodecanoic acid did not increase total catch olD. citri as compared with blank traps at the dosages tested; however, the sex ratio ofpsyllid catch was male biased on traps baited with the highest lure loading dosage tested （10.0 mg）.展开更多
Discrimination between nestmates and non-nestmates in social insects is thought to rely on the pattern of cuticular hydrocarbons.We investigated the cuticular hydrocarbon profiles of 2 parapatric sibling ant species,T...Discrimination between nestmates and non-nestmates in social insects is thought to rely on the pattern of cuticular hydrocarbons.We investigated the cuticular hydrocarbon profiles of 2 parapatric sibling ant species,Temnothorax nylanderi(Förster,1850)and Temnothorax crassispinus(Karavaiev,1926),and their hybrid.We found that although the profiles show considerable similarities,a discriminant analysis based on the relative peak areas of cuticular hydrocarbons separates the 3 taxa.The profiles of hybrids were not consistently intermediate between those of the paternal species,suggesting either non-additive interactions among the parental biosynthetic pathways or systematic differ-ences in environment-derived odor cues.展开更多
It is well established that pheromones are used by insects to transmit infor-mation between individuals.However,research has revealed that individual insects can be both the sender and the receiver of some pheromonal ...It is well established that pheromones are used by insects to transmit infor-mation between individuals.However,research has revealed that individual insects can be both the sender and the receiver of some pheromonal signals.It is therefore interesting to consider whether the pheromonal state of an individual insect can exert an effect on itself.In this study,we monitored the sleep activity of single flies exhibiting a mutation that leads to pheromonal deficiency and found that cuticular hydrocarbons(CHs)exerted self-regulatory effects on the amount of sleep experienced by these flies.To identify the physiological significance of this mechanism,we compared the amounts of sleep in in-dividual young flies and individual old flies(flies are known to sleep less as they get older)and compared this data with young and old flies exhibiting mutations that lead to CH reception defects.The differences in the amount of sleep experienced by young and old mutant flies were significantly lower than those of the control flies.Our data show that hydrocarbon signals produced by the cuticle in Drosophila can be self-perceived and regulate the amount of sleep acquired in a maturation-dependent manner.展开更多
文摘CoCu/TiO_2 catalysts promoted using alkali metals（Li, Na, K, Rb, and Cs） were prepared by the homogeneous deposition-precipitation method followed by the incipient wetness impregnation method. The influences of the alkali metals on the physicochemical properties of the CoCu/TiO_2 catalysts and the catalytic performance for CO_2 hydrogenation to long-chain hydrocarbons（C_（5＋））were investigated in this work. According to the characterization of the catalysts based on X-ray photoelectron spectroscopy, X-ray diffraction, CO_2 temperature-programmed desorption（TPD）, and H_2-TPD, the introduction of alkali metals could increase the CO_2 adsorption and decrease the H_2 chemisorption, which could suppress the formation of CH_4, enhance the production of C_（5＋）, and decrease the hydrogenation activity. Among all the promoters, the Na-modified CoCu/TiO_2 catalyst provided the maximum C_（5＋） yield of 5.4%, with a CO_2 conversion of 18.4% and C_（5＋） selectivity of42.1%, because it showed the strongest basicity and a slight decrease in the amount of H_2 desorption;it also exhibited excellent catalytic stability of more than 200 h.
文摘Huanglongbing （HLB） is the most destructive disease of citrus worldwide. The Asian citrus psyllid, Diaphorina citri Kuwayama （Hemiptera： Psyllidae）, is the vector of the phloem-inhabiting bacterium, Candidatus Liberibacter asiaticus, which is presumed to cause HLB in Florida citrus. Laboratory and field studies were conducted to examine the behavioral responses of male and female D. cirri to their cuticular extracts. In olfactometer assays, more male D. citri were attracted to one, five, or 10 female cuticular extract equivalent units than blank controls. The results were confirmed in field studies in which clear or yellow traps baited with 10 female cuticular extract equivalent units attracted proportionately more males than clear traps baited with male cuticular extract or unbaited traps. Analyses of cuticular constituents of male and female D. citri revealed differences between the sexes in chemical composition of their cuticular extracts. Laboratory bioassays with synthetic chemicals identified from cuticular extracts indicated that dodecanoic acid attracted more males than clean air. Traps baited with dodecanoic acid did not increase total catch olD. citri as compared with blank traps at the dosages tested; however, the sex ratio ofpsyllid catch was male biased on traps baited with the highest lure loading dosage tested （10.0 mg）.
基金This project was carried out with permission from Al-Azhar University,Cairo and the Ministry of High Educa-tion of the Arab Republic of Egypt,and supported by funds from the Deutsche Forschungsgemeinschaft.
文摘Discrimination between nestmates and non-nestmates in social insects is thought to rely on the pattern of cuticular hydrocarbons.We investigated the cuticular hydrocarbon profiles of 2 parapatric sibling ant species,Temnothorax nylanderi(Förster,1850)and Temnothorax crassispinus(Karavaiev,1926),and their hybrid.We found that although the profiles show considerable similarities,a discriminant analysis based on the relative peak areas of cuticular hydrocarbons separates the 3 taxa.The profiles of hybrids were not consistently intermediate between those of the paternal species,suggesting either non-additive interactions among the parental biosynthetic pathways or systematic differ-ences in environment-derived odor cues.
基金supported by the National Natural Science Foundation of China(grant number 31772535)Juan Du by the National Natural Science Foundation of China(grant number 31572317)to Zhangwu Zhao.
文摘It is well established that pheromones are used by insects to transmit infor-mation between individuals.However,research has revealed that individual insects can be both the sender and the receiver of some pheromonal signals.It is therefore interesting to consider whether the pheromonal state of an individual insect can exert an effect on itself.In this study,we monitored the sleep activity of single flies exhibiting a mutation that leads to pheromonal deficiency and found that cuticular hydrocarbons(CHs)exerted self-regulatory effects on the amount of sleep experienced by these flies.To identify the physiological significance of this mechanism,we compared the amounts of sleep in in-dividual young flies and individual old flies(flies are known to sleep less as they get older)and compared this data with young and old flies exhibiting mutations that lead to CH reception defects.The differences in the amount of sleep experienced by young and old mutant flies were significantly lower than those of the control flies.Our data show that hydrocarbon signals produced by the cuticle in Drosophila can be self-perceived and regulate the amount of sleep acquired in a maturation-dependent manner.
