Quality of soil humic substances and compost quality was assessed using different techniques of fluorescence spectroscopy. Emission, excitation, synchronous and emission-excitation matrix help us to characterize diffe...Quality of soil humic substances and compost quality was assessed using different techniques of fluorescence spectroscopy. Emission, excitation, synchronous and emission-excitation matrix help us to characterize different fluorophores in humic substances molecule. Content of stabile carbon forms in soil was assessed by humic substances fractionation. Content of labile water extractable carbon and nitrogen was determined by analyzer Shimadzu TOC-VCSH with chemo-luminescent detection in infrared spectral region. Results showed that compost amendment caused changes in both stabile （recalcitrant） and labile carbon content. Humic substances isolated from compost consist mainly of simple structural components of wide molecular heterogeneity and low molecular weight. Humification degree and content of conjugated fluorophores in compost was lower compared with stabile soil humic substances. The last contained more conjugated aromatic π-electron systems with electron-withdrawing functional groups, which are responsible for the fluorescence shift to lower energy levels or longer wavelengths.展开更多
The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor （SBR）, and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances （EPS） of sludge samples were e...The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor （SBR）, and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances （EPS） of sludge samples were extracted and analyzed during the granulation and storage process. The results show that the contents of protein and EPS increase along with the granulation process, while polysaccharides remain almost unchanged. The content of protein in EPS is almost two-fold larger than that of polysaccharides in granular sludge cultivated with municipal wastewater. Moreover, some of the granules disintegrate during storage, corresponding to the decrease of protein contents in EPS. Three peaks are identified in three-dimensional excitation emission matrix （EEM） fluorescence spectra of the EPS in the aerobic granules. Two peaks （A and B） are attributed to the protein-like fluorophores, and the third （peak C） is related to visible fulvic-like substances. Peak A gradually disappears during storage, while a new peak related to ultraviolet fulvic acid （peak D） is formed. The formation and the stability of aerobic granules are closely dependent on the quantity and composition of EPS proteins. Peak C has no obvious changes during granulation, while the fulvic-like substances present an increase in fluorescence intensities during storage, accompanied with an increase in structural complexity. The fulvie-like substances are also associated with the disintegration of the aerobic granules.展开更多
A model HA-type polymer of para-benzoquinone synthetic humic acid (SHA) and its complexes with copper, iron and manganese metal ions were studied using atomic force microscopy (AFM). Natural humic acids (HA) and synth...A model HA-type polymer of para-benzoquinone synthetic humic acid (SHA) and its complexes with copper, iron and manganese metal ions were studied using atomic force microscopy (AFM). Natural humic acids (HA) and synthetic humic acids (SHA) were examined by fluorescence spectroscopy, which indicated similarity of SHA and HA spectra. The AFM images of SHA and its complexes revealed variable morphologies, such as small spheres, aggregates and a sponge-like structure. The SHA complexes displayed morphologies similar to those of natural HA. The presence of copper, iron and manganese ions led to the formation of aggregate-type structures in an apparent arrangement of smaller SHA particles.展开更多
Biosorption of extracellular polymeric substances （EPS） from Synechocystis sp. （cyanobacterium） with Cu（II） was investigated using fluorescence spectroscopy. Three fluorescence peaks were found in the excitation...Biosorption of extracellular polymeric substances （EPS） from Synechocystis sp. （cyanobacterium） with Cu（II） was investigated using fluorescence spectroscopy. Three fluorescence peaks were found in the excitation-emission matrix （EEM） fluorescence spectra of EPS. Fluorescence of peak A （Ex/Em = 275/452 nm） and peak C （Ex/Em= 350/452nm） were originated from humic-like substances and fluorescence of peak B （Ex/ Em= 275/338nm） was attributed to protein-like sub- stances. Fluorescence of peaks A, B, and C could be quenched by Cu（II）. The effective quenching constants （lg Ka） were 2.8-5.84 for peak A, 6.4-9.24 for peak B, and 3.48-6.68 for peak C, respectively. The values of lg Ka showed a decreasing trend with increasing temperature, indicating that the quenching processes were static in nature. The binding constants （lg Kb） followed the order of peak A 〉 peak B 〉 peak C, implying that the humic-like substances in EPS have greater Cu（II） binding capacity than the protein-like substances. The binding site number, n, in EPS-Cu（II） complexes for peaks A, B, and C was less than 1. This suggests the negative cooperativity between multiple binding sites and the presence of more than one Cu binding site.展开更多
We proposed a method to identify spatial position of fluorescent substance in living body. With the assumption that cancerous lesion has been successfully targeted by a specific exogenous fluorescent probe, the object...We proposed a method to identify spatial position of fluorescent substance in living body. With the assumption that cancerous lesion has been successfully targeted by a specific exogenous fluorescent probe, the objective of this study is to seek a straightforward and simple solution for localizing fluorescent material inside scattering turbid media. Our method enables estimation of horizontal position and depth of the fluorescent substance. A fluorescence detection system and corresponding simulation method are also developed to evaluate the proposed method. The phantom experimental results showed that the fluorescence produced by the fluorescent substance in scattering medium that simulates the adipose tissue could be detected. The fluorescence localizing can provide more precision position information to surgeons as to whether resection of certain parts of stomach is necessary. This method is possible to be used in gastric cancer diagnosis, therefore helping to reduce over-resection.展开更多
文摘Quality of soil humic substances and compost quality was assessed using different techniques of fluorescence spectroscopy. Emission, excitation, synchronous and emission-excitation matrix help us to characterize different fluorophores in humic substances molecule. Content of stabile carbon forms in soil was assessed by humic substances fractionation. Content of labile water extractable carbon and nitrogen was determined by analyzer Shimadzu TOC-VCSH with chemo-luminescent detection in infrared spectral region. Results showed that compost amendment caused changes in both stabile （recalcitrant） and labile carbon content. Humic substances isolated from compost consist mainly of simple structural components of wide molecular heterogeneity and low molecular weight. Humification degree and content of conjugated fluorophores in compost was lower compared with stabile soil humic substances. The last contained more conjugated aromatic π-electron systems with electron-withdrawing functional groups, which are responsible for the fluorescence shift to lower energy levels or longer wavelengths.
基金Project(2006AA06Z318) supported by the National High-Tech Research and Development Program of China
文摘The aerobic granular sludge was cultivated in a pilot-scale sequencing batch reactor （SBR）, and some of the granules were stored at 8 ℃ for 150 d. Extracellular polymeric substances （EPS） of sludge samples were extracted and analyzed during the granulation and storage process. The results show that the contents of protein and EPS increase along with the granulation process, while polysaccharides remain almost unchanged. The content of protein in EPS is almost two-fold larger than that of polysaccharides in granular sludge cultivated with municipal wastewater. Moreover, some of the granules disintegrate during storage, corresponding to the decrease of protein contents in EPS. Three peaks are identified in three-dimensional excitation emission matrix （EEM） fluorescence spectra of the EPS in the aerobic granules. Two peaks （A and B） are attributed to the protein-like fluorophores, and the third （peak C） is related to visible fulvic-like substances. Peak A gradually disappears during storage, while a new peak related to ultraviolet fulvic acid （peak D） is formed. The formation and the stability of aerobic granules are closely dependent on the quantity and composition of EPS proteins. Peak C has no obvious changes during granulation, while the fulvic-like substances present an increase in fluorescence intensities during storage, accompanied with an increase in structural complexity. The fulvie-like substances are also associated with the disintegration of the aerobic granules.
基金The authors acknowledge CAPES(Coordenação de Aperfeiçoamento de Pessoal de Nível Superior)and CNPq(Conselho Nacional de Desenvolvimento Científico e Tecnológico)process 302756/2009-4 for their financial supportEMBRAPA(Empresa Brasileira de Pesqui-sa Agropecuária)for its structural support of this work
文摘A model HA-type polymer of para-benzoquinone synthetic humic acid (SHA) and its complexes with copper, iron and manganese metal ions were studied using atomic force microscopy (AFM). Natural humic acids (HA) and synthetic humic acids (SHA) were examined by fluorescence spectroscopy, which indicated similarity of SHA and HA spectra. The AFM images of SHA and its complexes revealed variable morphologies, such as small spheres, aggregates and a sponge-like structure. The SHA complexes displayed morphologies similar to those of natural HA. The presence of copper, iron and manganese ions led to the formation of aggregate-type structures in an apparent arrangement of smaller SHA particles.
基金This work was supported by Program of 100 Distinguished Young Scientists of the Chinese Academy of Sciences and National Natural Science Foundation of China （Grant Nos. Ul120302 and 21177127）.
文摘Biosorption of extracellular polymeric substances （EPS） from Synechocystis sp. （cyanobacterium） with Cu（II） was investigated using fluorescence spectroscopy. Three fluorescence peaks were found in the excitation-emission matrix （EEM） fluorescence spectra of EPS. Fluorescence of peak A （Ex/Em = 275/452 nm） and peak C （Ex/Em= 350/452nm） were originated from humic-like substances and fluorescence of peak B （Ex/ Em= 275/338nm） was attributed to protein-like sub- stances. Fluorescence of peaks A, B, and C could be quenched by Cu（II）. The effective quenching constants （lg Ka） were 2.8-5.84 for peak A, 6.4-9.24 for peak B, and 3.48-6.68 for peak C, respectively. The values of lg Ka showed a decreasing trend with increasing temperature, indicating that the quenching processes were static in nature. The binding constants （lg Kb） followed the order of peak A 〉 peak B 〉 peak C, implying that the humic-like substances in EPS have greater Cu（II） binding capacity than the protein-like substances. The binding site number, n, in EPS-Cu（II） complexes for peaks A, B, and C was less than 1. This suggests the negative cooperativity between multiple binding sites and the presence of more than one Cu binding site.
基金Grant-in-Aid for Scientific Research of JSPSgrant number:23680049
文摘We proposed a method to identify spatial position of fluorescent substance in living body. With the assumption that cancerous lesion has been successfully targeted by a specific exogenous fluorescent probe, the objective of this study is to seek a straightforward and simple solution for localizing fluorescent material inside scattering turbid media. Our method enables estimation of horizontal position and depth of the fluorescent substance. A fluorescence detection system and corresponding simulation method are also developed to evaluate the proposed method. The phantom experimental results showed that the fluorescence produced by the fluorescent substance in scattering medium that simulates the adipose tissue could be detected. The fluorescence localizing can provide more precision position information to surgeons as to whether resection of certain parts of stomach is necessary. This method is possible to be used in gastric cancer diagnosis, therefore helping to reduce over-resection.
