Diatoms are the only ecological phytoplankton that require silicic acid for growth.They are also the dominant contributor of ocean's total primary productivity.Generation and circulation with silica walls,which th...Diatoms are the only ecological phytoplankton that require silicic acid for growth.They are also the dominant contributor of ocean's total primary productivity.Generation and circulation with silica walls,which the siliceous organisms form,is an important component of the marine biological pump.It is crucial to the study of the operational mechanisms of biological pump with different sea areas.Moreover,it is the key link to the study of global silicon cycle.This paper introduces the basic mechanism of the formation of diatom silica walls and a new way of researching silicic acid metabolism,namely the 2-(4-pyridyl)-5-((4-(2-dimethylaminoethylaminocarbamoyl)-methoxy)phenyl)oxazole(PDMPO) dyeing method.Under a fluorescence microscope after excitation with bright green fluorescence,it can combine with silicic acid to form a complex into the Si deposition within diatom cells.The advantage of this method is that it can monitor the metabolism of silicate after adding PDMPO.For experimentation and sample collection in each of the specified time points,samples were determinated through the unutilized silicic acid,silica dissoluble intracellular and Si deposition within diatom cells,not only using hot alkaline digestions method but also PDMPO dyeing method.Results showed a good linear relationship between PDMPO fluorescent value and biogenic silica concentration.It was also indicated that PDMPO had no deleterious impact on Skeletonema cf.costatum growth for 34 h and was useful for tracking newly-deposited biogenic silica in diatoms' frustules.展开更多
We investigate the geometries and energies of seven electronic states X-1A1, A1B1, a-3B1, B-1A2,b-3A2, C1B2 and c-3B2 of CF2 carbene using internally contracted multireference configuration interaction methods includi...We investigate the geometries and energies of seven electronic states X-1A1, A1B1, a-3B1, B-1A2,b-3A2, C1B2 and c-3B2 of CF2 carbene using internally contracted multireference configuration interaction methods including Davidson correction （icMRCIq-Q） with different basis sets aug-cc-pVXZ （X=T, Q, 5）. For the first time, the potential energy curves of electronic states of CF2 related icMRCI＋Q/aug-cc-pVTZ level. The ab initio results will and dynamics of electronic states of CF2 radical. to the lowest dissociation limit are calculated at the further increase our understanding of the structures展开更多
基金The National Natural Science Foundation of China primarily supported this studyDr.J.Sun received grants from the National Natural Science Foundation of China(Nos.41276124 and 41676112)+2 种基金Program for Changjiang Scholars and the Science Fund for University Creative Research Groups in Tianjin(No.TD12-5003)Dr.Y.Feng received grants from the National Natural Science Foundation of China(No.41306118)Dr.G.Zhang received grants from the Foundation of Tianjin Key Laboratory of Marine Resources and Chemistry(Tianjin University of Science&Technology),P.R.China(No.201504)
文摘Diatoms are the only ecological phytoplankton that require silicic acid for growth.They are also the dominant contributor of ocean's total primary productivity.Generation and circulation with silica walls,which the siliceous organisms form,is an important component of the marine biological pump.It is crucial to the study of the operational mechanisms of biological pump with different sea areas.Moreover,it is the key link to the study of global silicon cycle.This paper introduces the basic mechanism of the formation of diatom silica walls and a new way of researching silicic acid metabolism,namely the 2-(4-pyridyl)-5-((4-(2-dimethylaminoethylaminocarbamoyl)-methoxy)phenyl)oxazole(PDMPO) dyeing method.Under a fluorescence microscope after excitation with bright green fluorescence,it can combine with silicic acid to form a complex into the Si deposition within diatom cells.The advantage of this method is that it can monitor the metabolism of silicate after adding PDMPO.For experimentation and sample collection in each of the specified time points,samples were determinated through the unutilized silicic acid,silica dissoluble intracellular and Si deposition within diatom cells,not only using hot alkaline digestions method but also PDMPO dyeing method.Results showed a good linear relationship between PDMPO fluorescent value and biogenic silica concentration.It was also indicated that PDMPO had no deleterious impact on Skeletonema cf.costatum growth for 34 h and was useful for tracking newly-deposited biogenic silica in diatoms' frustules.
基金Supported by the 2014 Postdoctoral Sustentation Fund of Qingdao under Grant No 01020120517the Natural Science Foundation of Shandong Province under Grant No ZR2014AP001+1 种基金the National Natural Science Foundation of China under Grant No11447226the Scientific Research Foundation of Shandong University of Science and Technology for Recruited Talents under Grant No 2015RCJJ015
文摘We investigate the geometries and energies of seven electronic states X-1A1, A1B1, a-3B1, B-1A2,b-3A2, C1B2 and c-3B2 of CF2 carbene using internally contracted multireference configuration interaction methods including Davidson correction （icMRCIq-Q） with different basis sets aug-cc-pVXZ （X=T, Q, 5）. For the first time, the potential energy curves of electronic states of CF2 related icMRCI＋Q/aug-cc-pVTZ level. The ab initio results will and dynamics of electronic states of CF2 radical. to the lowest dissociation limit are calculated at the further increase our understanding of the structures
