To improve the deteriorated capacity gain and source recovery performance due to channel mismatch problem,this paper reports a research about blind separation method against channel mismatch in multiple-input multiple...To improve the deteriorated capacity gain and source recovery performance due to channel mismatch problem,this paper reports a research about blind separation method against channel mismatch in multiple-input multiple-output(MIMO) systems.The channel mismatch problem can be described as a channel with bounded fluctuant errors due to channel distortion or channel estimation errors.The problem of blind signal separation/extraction with channel mismatch is formulated as a cost function of blind source separation(BSS) subject to the second-order cone constraint,which can be called as second-order cone programing optimization problem.Then the resulting cost function is solved by approximate negentropy maximization using quasi-Newton iterative methods for blind separation/extraction source signals.Theoretical analysis demonstrates that the proposed algorithm has low computational complexity and improved performance advantages.Simulation results verify that the capacity gain and bit error rate(BER) performance of the proposed blind separation method is superior to those of the existing methods in MIMO systems with channel mismatch problem.展开更多
The affinity heptapeptide(HWWWPAS)for insulin,selected from phage display library,was coupled to EAH Sepharose 4B gel and packed to a 1-mL column.The column was used for the affinity purification of insulin from prote...The affinity heptapeptide(HWWWPAS)for insulin,selected from phage display library,was coupled to EAH Sepharose 4B gel and packed to a 1-mL column.The column was used for the affinity purification of insulin from protein mixture and commercial insulin preparation.It was observed that the minor impurity in the commercial insulin was removed by the affinity chromatography.Nearly 40 mg of insulin could be purified with the 1-mL affinity column.The results revealed the high specificity and capacity of the affinity column for insulin purification.Moreover,based on the analysis of the amino acids in the peptide sequence,shorter peptides were designed and synthesized for insulin chromatography.As a result,HWWPS was found to be a good alternative to HWWWPAS,while the other two peptides with three or four amino acids showed weak affinity for insulin.The results indicated that the peptide sequence of HWWWPAS was quite conservative for specific binding of insulin.展开更多
The conventional saponification method could result in lower recoveries and artificial changes of longchain fatty acids. The main reason is the error judgment of the intermediate layer suspended between the aqueous an...The conventional saponification method could result in lower recoveries and artificial changes of longchain fatty acids. The main reason is the error judgment of the intermediate layer suspended between the aqueous and organic layer during the liquid–liquid extraction process.This study shows that the intermediate layer consists of lots of medium- to long-chain carboxylic salts for their special physical and chemical properties. An improved saponification extraction method is also developed and the results show that the carboxylic salts distributed in the intermediate layer could be obtained completely, which greatly enhances the authenticity and accuracy of fatty acid analysis. Additionally, the possible reasons of formation of the intermediate layer are also discussed.展开更多
This study evaluated in vitro activity of ethanol extract, fractions, and isolated substance from Amazon species against promastigotes of L. amazonensis. The ethanol extracts were concentrated and fractionation. The a...This study evaluated in vitro activity of ethanol extract, fractions, and isolated substance from Amazon species against promastigotes of L. amazonensis. The ethanol extracts were concentrated and fractionation. The anti-promastigote activity was evaluated through the cell viability assessment method （MTT）. The ethanol extract, fractions, and isolated substance from Himatanthus articulatus and Parahancorniafasciculata were inactive in promastigote ofL. amazonensis, as the ethanol extract ofPhysalis angulata. The hexane fractions from different parts ofMontrichardia linifera showed anti-promastigote activity probably due to the presence of steroids and terpenes. All species in studies were inactive, except ofM. linifera. The few polar constituents can be responsible for the activity. Therefore, the isolation and purification of the active on L. amazonensis promastigotes are urgently required.展开更多
Isolation and purification of single-walled carbon nanotubes （SWCNTs） are prerequisites for their implementation in various applications. In this work, we present a fast （-5 min）, low-cost, and easily scalable ben...Isolation and purification of single-walled carbon nanotubes （SWCNTs） are prerequisites for their implementation in various applications. In this work, we present a fast （-5 min）, low-cost, and easily scalable bench-top approach to the extraction of high-quality isolated SWCNTs from bundles and impurities in an aqueous dispersion. The extraction procedure, based on aqueous two-phase （ATP） separation, is widely applicable to any SWCNT source （tested on samples up to 1.7 nm in diameter） and independent of defect density, purity, diameter, and length. The extracted dispersions demonstrate that the removal of large aggregates, small bundles, and impurities is comparable to that by density gradient ultracentrifugation, but without the need for high-end instrumentation. Raman and fluorescence-excitation spectroscopy, single-nanotube fluorescence imaging, atomic force and transmission electron microscopy, and thermogravimetric analysis all confirm the high purity of the isolated SWCNTs. By predispersing the SWCNTs without sonication （only gentle stirring）, full-length, pristine SWCNTs can be isolated （tested up to 20 μm）. Hence, this simple ATP method will find immediate application in the generation of SWCNT materials for all levels of nanotube research and applications, from fundamental studies to high-performance devices.展开更多
基金supported by Sichuan Youth Science and Technology Innovation Research Team Project(No.2015TD0022)the Talents Project of Sichuan University of Science and Engineering(No.2017RCL11 and No.2017RCL10)the first batch of science and technology plan key R&D project of Sichuan province(No.2017GZ0068)
文摘To improve the deteriorated capacity gain and source recovery performance due to channel mismatch problem,this paper reports a research about blind separation method against channel mismatch in multiple-input multiple-output(MIMO) systems.The channel mismatch problem can be described as a channel with bounded fluctuant errors due to channel distortion or channel estimation errors.The problem of blind signal separation/extraction with channel mismatch is formulated as a cost function of blind source separation(BSS) subject to the second-order cone constraint,which can be called as second-order cone programing optimization problem.Then the resulting cost function is solved by approximate negentropy maximization using quasi-Newton iterative methods for blind separation/extraction source signals.Theoretical analysis demonstrates that the proposed algorithm has low computational complexity and improved performance advantages.Simulation results verify that the capacity gain and bit error rate(BER) performance of the proposed blind separation method is superior to those of the existing methods in MIMO systems with channel mismatch problem.
基金Supported by Natural Science Foundation of China(No.20476081)the Programfor Changjiang ScholarsInnovative Research Team in University from the Ministry of Education of China.
文摘The affinity heptapeptide(HWWWPAS)for insulin,selected from phage display library,was coupled to EAH Sepharose 4B gel and packed to a 1-mL column.The column was used for the affinity purification of insulin from protein mixture and commercial insulin preparation.It was observed that the minor impurity in the commercial insulin was removed by the affinity chromatography.Nearly 40 mg of insulin could be purified with the 1-mL affinity column.The results revealed the high specificity and capacity of the affinity column for insulin purification.Moreover,based on the analysis of the amino acids in the peptide sequence,shorter peptides were designed and synthesized for insulin chromatography.As a result,HWWPS was found to be a good alternative to HWWWPAS,while the other two peptides with three or four amino acids showed weak affinity for insulin.The results indicated that the peptide sequence of HWWWPAS was quite conservative for specific binding of insulin.
基金supports by the National Natural Science Foundation of China (No.41003021)the Key Laboratory Project of Gansu Province (Grant No.1309RTSA041)
文摘The conventional saponification method could result in lower recoveries and artificial changes of longchain fatty acids. The main reason is the error judgment of the intermediate layer suspended between the aqueous and organic layer during the liquid–liquid extraction process.This study shows that the intermediate layer consists of lots of medium- to long-chain carboxylic salts for their special physical and chemical properties. An improved saponification extraction method is also developed and the results show that the carboxylic salts distributed in the intermediate layer could be obtained completely, which greatly enhances the authenticity and accuracy of fatty acid analysis. Additionally, the possible reasons of formation of the intermediate layer are also discussed.
文摘This study evaluated in vitro activity of ethanol extract, fractions, and isolated substance from Amazon species against promastigotes of L. amazonensis. The ethanol extracts were concentrated and fractionation. The anti-promastigote activity was evaluated through the cell viability assessment method （MTT）. The ethanol extract, fractions, and isolated substance from Himatanthus articulatus and Parahancorniafasciculata were inactive in promastigote ofL. amazonensis, as the ethanol extract ofPhysalis angulata. The hexane fractions from different parts ofMontrichardia linifera showed anti-promastigote activity probably due to the presence of steroids and terpenes. All species in studies were inactive, except ofM. linifera. The few polar constituents can be responsible for the activity. Therefore, the isolation and purification of the active on L. amazonensis promastigotes are urgently required.
文摘Isolation and purification of single-walled carbon nanotubes （SWCNTs） are prerequisites for their implementation in various applications. In this work, we present a fast （-5 min）, low-cost, and easily scalable bench-top approach to the extraction of high-quality isolated SWCNTs from bundles and impurities in an aqueous dispersion. The extraction procedure, based on aqueous two-phase （ATP） separation, is widely applicable to any SWCNT source （tested on samples up to 1.7 nm in diameter） and independent of defect density, purity, diameter, and length. The extracted dispersions demonstrate that the removal of large aggregates, small bundles, and impurities is comparable to that by density gradient ultracentrifugation, but without the need for high-end instrumentation. Raman and fluorescence-excitation spectroscopy, single-nanotube fluorescence imaging, atomic force and transmission electron microscopy, and thermogravimetric analysis all confirm the high purity of the isolated SWCNTs. By predispersing the SWCNTs without sonication （only gentle stirring）, full-length, pristine SWCNTs can be isolated （tested up to 20 μm）. Hence, this simple ATP method will find immediate application in the generation of SWCNT materials for all levels of nanotube research and applications, from fundamental studies to high-performance devices.
