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Science China Chemistry 2015年第5期58卷 885-891页

作者： Jingfang Guo Yamei Yang Xiaoli Hu yuanfang li Key Laboratory of Luminescent and Real-Time Analytical Chemistry Ministry of Education College of Chemistry and Chemical Engineering Southwest University

A simple and sensitive method for detection of captopril was established based on its obstructive effect on nanomaterial sur- face energy transfer （NSET）. It was found that the acridine orange （AO） could be adsorbed onto the surface of citrated-gold nanoparticles （AuNPs） through electrostatic interaction. Incidentally, the fluorescence of AO was quenched owing to the dipole-dipole interaction of NSET between AO fluorophore and the AuNPs. However, captopril could obstruct the occurrence of NSET between AO and AuNPs effectively with the formation of Au-S covalent bonds between it and the AuNPs. Consequently, AO molecules were moved away from the surface of AuNPs leading to a decline of the energy transfer efficiency. Moreover, the fluorescence of AO could be gradually restored with the addition of captopril. Under the optimal conditions, the recovered fluorescence intensity correlated linearly with the concentration of captopril in the range of 400 nmol/L-2.0μmol/L with a detection limit of 71 μmol/L. Besides, the proposed method was successfully applied for the detection of captopril in troches with the recovery of 93%-102% and the RSD lower than 2.24%. The results were in good agreement with those obtained from the HPLC method,

关键词： nanomaterial surface energy transfer gold nanoparticles acridine orange captopril

Shape- and size-dependent catalysis activities of iron-terephthalic acid metal-organic frameworks

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Science China Chemistry 2015年第10期58卷 1553-1560页

作者： Yali liu Pengfei Gao Chengzhi Huang yuanfang li Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University) Ministry of Education College of Chemistry and Chemical Engineering Southwest University College of Pharmaceutical Science Southwest University

Precise control of the size and morphology of metal-organic frameworks(MOFs) presents an important direction for extending these inorganic-organic materials to many more advanced applications. However, because of the limit of the crystal-growth rule and mechanism, good-control of the size and morphology of MOFs remains challenging. In this contribution, an iron-terephthalic acid metal-organic framework with different shapes(octahedron, spindle and bipyramidal hexagonal) was easily and reproducibly synthesized via a solvothermal method. Sodium acetate and glycerol were used as modulators. Mechanism studies showed that the crystal nucleation rate and orientational growth both play important roles in determining the final shape of the MOFs. Further investigations showed that the as prepared MOFs exhibit shape-dependent catalytic activities, which means that MOFs can be designed to perform different catalytic functions. This investigation not only provides an effective guideline for the precise control of the size and morphology of metal-organic frameworks, but also extends MOFs to much more advanced applications in terms of catalyst chemistry.

关键词： controllable synthesis metal-organic frameworks catalytic activity

Spatio-temporal analysis of cropland change in the Guanzhong area, China, from 1650 to 2016

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Journal of Geographical Sciences 2021年第9期31卷 1381-1400页

作者： WEI Xueqiong li yuanfang GUO Yu CHEN Tiexi li Beibei School of Geographical Sciences Nanjing University of Information Science and TechnologyNanjing 210044China Research Institute for History of Science and Technology Nanjing University of Information Science and TechnologyNanjing 210044China

As one of the most critical impact factors of global change,historical land-use change is an indispensable input in climate and environment *** better understand the cropland change in the Guanzhong area,gazetteers,statistics,and survey data were collected as data *** of registered tax-paying cropland data collection,selection of time points,and data interpolation and calibration were used to reconstruct changes in the cropland *** cropland area data at the county level were allocated to 1 km×1 km grid *** total cropland area in the Guanzhong area was influenced by changes in population,wars,natural disasters,and land-use types,and it fluctuated from 1650 to *** 1780 to 1830,the cropland expanded in the northern and western parts of Guanzhong area,and the cropland in the north of Qinling Mountains increased *** spatial pattern of cropland reached its maximum range in 1980,and the cropland area declined in the whole study area,especially in the cities of Xi’an and Xianyang in *** comparison between HYDE 3.2 and the data obtained in this study showed that the grid cells of HYDE 3.2 exhibit lower values of cropland area fractions in the Guanzhong Basin and higher values in high-altitude areas around the Guanzhong Basin as compared to those in this study.

关键词： cropland change reconstruction Guanzhong area past 300 years

Maintenance of the activity of mono-dispersed Au and Ag nano-particles embedded in agar gel for ion-sensing and antimicrobial applications

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Science China Chemistry 2015年第4期58卷 666-672页

作者： Yijuan Long Yi Wang Yue liu Qiaoling Zeng yuanfang li Key Laboratory on Luminescence and Real-Time Analysis Ministry of Education College of Chemistry and Chemical Engineering Southwest University College of Pharmaceutical Sciences Southwest University

Composite materials were synthesized by encapsulating Au and Ag nanoparticles in an agar gel matrix. These metallic nano-particles were found to be separately stored, so their optical, catalytic, and antibacterial properties were retained both in the composite gel and a composite membrane. The composite gels were stable under hard external conditions. Based on this, a sensor for the detection of Hg2+ was developed using the Au nanoparticle/agar composite gel. Antibacterial materials were achieved using the Ag nanoparticle/agar composite gel and composite membrane. These two Ag nanoparticle-based materials showed good antibacterial activity against Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus.

关键词： nanoparticles composite materials optical sensors

Facile synthesis of gold nanoflowers as SERS substrates and their morphological transformation induced by iodide ions

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Science China Chemistry 2016年第8期59卷 1045-1050页

作者： Shujun Zhen Tong Wu Xin Huang yuanfang li Chengzhi Huang Key Laboratory of Luminescent and Real-Time Analytical Chemistry (Southwest University) Ministry of Education College of Chemistry and Chemical Engineering Southwest University 400715 Chongqing China Department of ChemiStry and Chemical Engineeringl Yibin University Yibin 644000 China College of Pharmaceutical Science Southwest University Chongqing 400715 China

We report a new strategy to prepare gold nanoflowers （AuNFs） using a two-step seed-mediated method. The as-prepared AuNFs were employed as surface-enhance Raman scattering （SERS） substrates, showing strong signal enhancement. We further found that iodide ions （I^-） could selectively induce the morphological transformation of AuNFs to spheres, resulting in a blue-shift of the localized surface plasmon resonance （LSPR） bands, a color change of the AuNFs solution from blue to red, and decreased SERS activity. This behavior allows the AuNFs to be used in the determination of I^-.

关键词： gold nanoflowers SERS iodide ions

Highly selective recognition of adenosine 5′-triphosphate against other nucleosides triphosphate with a luminescent metal-organic framework of [Zn(BDC)(H_2O)_2]_n(BDC = 1,4-benzenedicarboxylate)

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Science China Chemistry 2013年第11期56卷 1651-1657页

作者： ZHAO XiJuan FANG JingMei li yuanfang HUANG ChengZhi Education Ministry Key Laboratory on Luminescence and Real-Time Analysis School of Chemistry and Chemical Engineering Southwest University College of Pharmaceutical Science Southwest University

Selective recognition of adenosine 5＇-triphosphate （ATP） is of great significance owing to its indispensable functions to organisms. Also, it is a challenging task because other nucleosides triphosphate hold the same triphosphate group and structurally planar bases as ATP. It is known that metal-organic frameworks （MOFs） are a new type of sensing material. In this work, highly selective recognition of ATP against other nucleosides triphosphate is successfully achieved with a luminescent MOF of [Zn（BDC）（H2O）2]n （BDC2- = 1,4-benzenedicarboxylate）. [Zn（BDC）（H2O）2]n dispersed in water shows a remarkable redshift of the emission wavelength upon addition of ATP, while cytidine 5＇-triphosphate （CTP）, uridine 5＇-triphosphate （UTP） and guanosine 5＇-triphosphate （GTP）, as well as some inorganic anions such as P2074- or PO43- can＇t induce such spectral change as ATP. 1H NMR, 31p NMR and Raman spectra indicate that both π-π stacking interactions and the coordination of Zn（II） with adenine and the phosphate group are involved in the interaction of [Zn（BDC）（H2O）2],, with ATP. In addition, the experimental results showed that the redshift extent of the emission wavelength of [Zn（BDC）（HzO）2]n has the linear relation- ship with the concentration of ATP in the range of 0.3-1.8 mmol/L. Based on this, the detection of ATP content in the sample of ATP injection was made with satisfactory results. This system pioneers the application of MOFs in the recognition of nucle- otides, and testifies that the participation of base in the recognition process can improve the selectivity against the other nucleotides.

关键词： adenosine 5'-triphosphate luminescent metal-organic framework

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The adsorption of silver nanoparticles on the proteins-immobilized glass slides and a visual investigation on proteins immobilization

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Science China Chemistry 2009年第5期52卷 639-643页

作者： liU Yue liNG Jian li yuanfang HUANG ChengZhi Key Laboratory of Luminescence and Real-Time Analysis Ministry of EducationSouthwest UniversityChongqing 400715China College of Pharmaceutical Science Southwest UniversityChongqing 400715China College of Chemistry and Chemical Engineering Southwest UniversityChongqing 400715China

Silver nanoparticles (AgNPs), owing to the property of plasmon resonance light scattering (PRLS), can be used as a light scattering spectral probe for visually tracing and detecting target molecules. In this study, we investigated the adsorption features of proteins immobilized on glass slides for AgNPs, and found that the scattering light of AgNPs adsorbed on the surface of glass slides could be seen by naked eyes under the irradiation of a common white light-emitting diode (LED) torch. Hereby, we established a method for visually determining the least complete quantity of immobilization of proteins on glass slides.

关键词： light scattering adsorption mechanism the least complete quantity of immobilization visualization

Thermodynamics of the long range assembly of safranine T on molecular surfaces of nucleic acids

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西南师范大学学报(自然科学版) 1998年第5期23卷 49-53页

作者： li yuanfang 不详

By making use of the fluorescence quenching properties of safranine T(ST) in its long range assembly on the molecular surfaces of nucleic acids, the assembly number and constant of ST with calf thymus DNA, fish sperm DNA and yeast RNA were determined at 12℃. The corresponding free energy change, enthalpy change and entropy change of the long range assembly were calculated at the same temperature. It was found the assembly complexes are very stable and the assembly is a spontaneous process characterized an entropy increase.

关键词： nucleic acids safranine T supramolecular interaction molecular emission spectroscopy

Investigations of the interaction between cuprous oxide nanoparticles and Staphylococcus aureus

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Science China Chemistry 2009年第7期52卷 1028-1032页

作者： SHEN Chengling li yuanfang QI WenJing HUANG ChengZhi Key Laboratory on Luminescence and Real-Time Analysis of Ministry of Education College of Chemistry and Chemical EngineeringSouthwest UniversityChongqing 400715China College of life Science Southwest UniversityChongqing 400715China College of Pharmaceutical Science Southwest UniversityChongqing 400715China

In this study, cuprous oxide nanoparticles of 30–50 nm in size were prepared in the presence of cetyltrimethylammonium bromide (CTAB). By taking Staphylococcus aureus (S.a), which always causes a variety of suppurative infections and toxinoses in humans, as a model bioparticle, the negative bioeffect of nano-Cu2O on S.a cells was evaluated, and minimal inhibitory concentration (MIC) was determined by imitating the MIC of antibiotics. Cellularity and bactericidal effect were measured by flow cytometry (FCM), dark field light scattering imaging and SEM photography. The results showed that nano-Cu2O particles may, by absorbing on the cell surface, impair the cell wall, damage the cell membrane, and finally increase permeability of the cell membrane, thus leading to a decrease in the viability of bacteria in the nano-Cu2O solution.

关键词： cuprous oxide nanoparticles Staphylococcus aureus minimal inhibitory concentration (MIC) flow cytometry (FCM)

One-step synthesis of fluorescent hydroxyls-coated carbon dots with hydrothermal reaction and its application to optical sensing of metal ions

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Science China Chemistry 2011年第8期54卷 1342-1347页

作者： liU liQin li yuanfang ZHAN Lei liU Yue HUANG ChengZhi Education Ministry Key Laboratory on Luminescence and Real-Time Analysis College of Chemistry and Chemical Engineering Southwest University Chongqing 400715 China CoUege of Pharmaceutical Sciences Southwest University Chongqing 400715 China

Carbon dots (CDs) with average diameter of 3.1 ± 0.5 nm were facilely synthesized with candle soot through hydrothermal reaction in sodium hydroxide aqueous solution. The as-prepared CDs were covered with a lot of hydroxyls, possessed properties of good water-solubility, anti-photobleaching, salt tolerance, and low cytotoxicity, and had a fluorescence quantum yield (QY) of about 5.5%. The fluorescence of the hydroxyls-coated CDs could be selectively quenched by metal ions such as Cr3+, Al3+ and Fe3+, which is because these metals can easily combine with the hydroxyl groups on the surface of CDs and induce aggregation of hydroxyls-coated CDs. Experiments showed that the quenching of Cr3+ had a Sterm-Volmer constant of 1.03 × 107 M-1 with a liner range of 1.0-25.0 μM and detection limit of 60 nM (3σ).

关键词： carbon dots fluorescence quantum yield cytotoxicity metal ions