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Chinese Journal of Aeronautics 2012年第4期25卷 631-639页

作者： tu jia GU Defeng WU Yi YI Dongyun College of Science National University of Defense TechnologyChangsha 410073China

In-flight phase center systematic errors of global positioning system（GPS） receiver antenna are the main restriction for improving the precision of precise orbit determination using dual-frequency *** approach is one of the valid methods for in-flight calibration of GPS receiver antenna phase center variations（PCVs） from ground *** this paper,followed by the correction model of spaceborne GPS receiver antenna phase center,ionosphere-free PCVs can be directly estimated by ionosphere-free carrier phase post-fit residuals of reduced dynamic orbit *** the data processing of gravity recovery and climate experiment（GRACE） satellites,the following conclusions are ***,the distributions of ionosphere-free carrier phase post-fit residuals from different periods have the similar systematic ***,simulations show that the influence of phase residual estimations for ionosphere-free PCVs on orbit determination can reach the centimeter ***,it is shown by in-flight data processing that phase residual estimations of current period could not only be used for the calibration for GPS receiver antenna phase center of foretime and current period,but also be used for the forecast of ionosphere-free PCVs in future period,and the accuracy of orbit determination can be well improved.

关键词： global positioning system precise orbit determination phase center variations phase residual estimation GRACE

Spaceborne GPS receiver antenna phase center offset and variation estimation for the Shiyan 3 satellite

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Chinese Journal of Aeronautics 2016年第5期29卷 1335-1344页

作者： Gu Defeng Lai Yuwang Liu Junhong Ju Bing tu jia College of Sciences National University of Defense Technology

In determining the orbits of low Earth orbit （LEO） satellites using spaceborne GPS, the errors caused by receiver antenna phase center offset （PCO） and phase center variations （PCVs） are gradually becoming a major limiting factor for continued improvements to accuracy. Shiyan 3, a small satellite mission for space technology experimentation and climate exploration, was developed by China and launched on November 5, 2008. The dual-frequency GPS receiver payload delivers 1 Hz data and provides the basis for precise orbit determination within the range of a few centimeters. The antenna PCO and PCV error characteristics and the principles influencing orbit determination are analyzed. The feasibility of PCO and PCV estimation and compensation in different directions is demonstrated through simulation and in-flight tests. The values of receiver antenna PCO and PCVs for Gravity Recovery and Climate Experiment （GRACE） and Shiyan 3 satellites are estimated from one month of data. A large and stable antenna PCO error, reaching up to 10.34 cm in the z-direction, is found with the Shiyan 3 satellite. The PCVs on the Shiyan 3 satellite are estimated and reach up to 3.0 cm, which is slightly larger than that of GRACE satellites. Orbit validation clearly improved with independent k-band ranging （KBR） and satellite laser ranging （SLR） measurements. For GRACE satellites, the average root mean square （RMS） of KBR residuals improved from 1.01 cm to 0.88 cm. For the Shiyan 3 satellite, the average RMS of SLR residuals improved from 4.95 cm to 4.06 cm.

关键词： GRACE Phase center offset Phase center variations Shiyan 3 Spaceborne GPS

Acceptorless dehydrogenative amination of alkenes for the synthesis of N-heterocycles

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Science China Chemistry 2022年第7期65卷 1330-1337页

作者： jia-Lin tu Wan Tang Shi-Hui He Ma Su Feng Liu jiangsu Key Laboratory of Neuropsychiatric Diseases and Department of Medicinal Chemistry College of Pharmaceutical SciencesSoochow UniversitySuzhou 215123China Key Laboratory of Organofluorine Chemistry Shanghai Institute of Organic ChemistryChinese Academy of SciencesShanghai 200032China

Catalytic amination of alkenes is one of the most attractive reactions for the construction of complex heterocycles with nitrogen centers. Herein, we present that synergistic photoredox and cobaloxime catalysis allows for highly efficient and mild dehydrogenative reactions between various NH nucleophiles and di-, tri-, and tetrasubstituted alkenes in the absence of external oxidants, thus enabling access to an array of N-heterocycles. Notably, both Z-and E-alkene-containing N-heterocycles are accessible. Mechanistic studies indicated that the Z-cinnamyl derivatives could be generated by photocatalytic E to Z alkene isomerization through an energy transfer process. Moreover, we find that sluggish energy transfer could inhibit the E to Z alkene isomerization process, thus offering the cinnamyl derivatives with E-selectivity. Our results highlight the benefits of the reactions using dual photoredox and cobaloxime catalysis to lead to diverse N-heterocycles.

关键词： nitrogen-centered radical alkene amination photoredox cyclization N-heterocycle

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Science Letters:Determination of benzalkonium chloride in viscous ophthalmic drops of azithromycin by high-performance liquid chromatography

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Journal of Zhejiang University-Science B(Biomedicine & Biotechnology) 2009年第12期10卷 877-882页

作者： Yan SHEN Sheng-jie XU Shi-chun WANG jia-sheng tu Department of Pharmaceutics China Pharmaceutical University Nanjing 210009 China Productivity Center of jiangsu Province Nanjing 210042 China

A high-performance liquid chromatography （HPLC） system was used in the reversed phase mode for the determination ofbenzalkonium chloride （BKC） in azithromycin viscous ophthalmic drops. A Venusil-XBP（L）-C18 （150 mm×4.6 mm, 5 gm） column was used at 50℃. The mobile phase consisted of a mixture of methanol-potassium phosphate （16：5, v/v）. Two sample preparation methods were compared. The results suggested that, compared with an extraction procedure, a deproteinization procedure was much quicker and more convenient. Using the deproteinization procedure for sample preparation, calibration curves were linear in the range 5.0-50μg/ml. The within-day and inter-day coefficients of variation were less than 10%. The average recoveries were determined as 96.70%, 98.52%, and 97.96% at concentrations of 10.0, 30.0, and 50.0 μg/ml, respectively. Variability in precision did not exceed 5%. In conclusion, this HPLC method using a simple sample treatment procedure appears suitable for monitoring BKC content in azithromycin viscous ophthalmic drops.

关键词： Benzalkonium chloride High-performance liquid chromatography Azithromycin Viscous ophthalmic drops

Root stoichiometric dynamics and homeostasis of invasive species Phyllostachys edulis and native species Cunninghamia lanceolata in a subtropical forest in China

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Journal of Forestry Research 2021年第5期32卷 2001-2010页

作者： Chao Peng jia tu Ming Yang Yong Meng Meiqun Li Wensheng Ai Institute of Bamboo Research Hunan Academy of ForestryChangsha 410004Hunan ProvinceP.R.China

The community species abundance and diversity declined with bamboo invasion had been widely reported ***,the physiological strategies used during root competition between native species and invasive bamboo are poorly *** clarify the mechanisms underlying such strategies,the stoichiometric dynamics and homeostasis of nitrogen,phosphorus,organic carbon in root orders of Phyllostachys edulis(I du[=Ⅰ-Pe,years 1 and 2];Ⅱdu[=Ⅱ-Pe,years 3 and 4]),Cunninghamia lanceolata in transition and pure forests were *** increasing intensity of bamboo invasion,N,P,and C content of *** root orders declined,N and P content in *** rhizome orders declined,while C increased,the stoichiometric ratios in mixed forest interface mainly increased,and the stoichiometric differences within native and invasive species root orders ***,the stoichiometric homeostasis index(H)of elements in the same root order and even the same elements in different root orders were not consistent.H of most root orders(except some HP)was greater than 4,the H ranked order wasⅠ-Pe>Cl>Ⅱ-Pe in mixed interfaces,and the N:P ratio of most species root orders was greater than 16,despite being affected by *** research concluded that the bamboo invasion narrows stoichiometric differences within root orders,and the juvenile bamboo rhizome has a stronger capacity for homeostatic regulation than in adult bamboo and ***,which is a key determinant of bamboo invasion success.

关键词： Bamboo invasion Root orders Nutrient dynamics Homeostatic regulation coefficient

Optimization and characterization of deoxypodophyllotoxin loaded mPEG-PDLLA micelles by central composite design with response surface methodology

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Chinese Journal of Natural Medicines 2018年第6期16卷 471-480页

作者： YU Ying-Lan LI Ya-Nan ZHANG Yong SUN Ru-Ning tu jia-Sheng SHEN Yan Department of Pharmaceutics School of PharmacyChina Pharmaceutical UniversityNanjing 210009China Children's Hospital of Nanjing Medical University Nanjing 210008China Department of Professional Institute China Pharmaceutical UniversityNanjing 210009China

The therapeutic application of deoxypodophyllotoxin(DPT) is limited due to its poor water solubility and stability. In the present study, the micelles assembled by the amphiphilic block copolymers(m PEG-PDLLA) were constructed to improve the solubility and safety of DPT for their in vitro and in vivo application. The central composite design was utilized to develop the optimal formulation composed of 1221.41 mg m PEG-PDLLA, the weight ratio of 1 : 4(m PEG-PDLLA : DPT), 30 m L hydration volume and the hydration temperature at 40 oC. The results showed that the micelles exhibited uniformly spherical shape with the diameter of 20 nm. The drug-loading and entrapment efficiency of deoxypodophyllotoxin-polymeric micelles(DPT-PM) were about(20 ± 2.84)% and(98 ± 0.79)%, respectively, indicating that the mathematical models predicted well for the results. Compared to the free DPT, the cytotoxicity showed that blank micelles possessed great safety for Hela cells. In addition, the DPT loaded micelle formulation achieved stronger cytotoxicity at the concentration of 1 × 10^(-7) mol·L^(-1), which showed significant difference from free DPT(P tumor therapy with DPT.

关键词： Deoxypodophyllotoxin Central composite design Micelles Cytotoxicity

Intracellular redox potential-driven live-cell synthesis of CdSe quantum dots in Staphylococcus aureus

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Science China Chemistry 2024年第3期67卷 990-999页

作者： Cai-Qin Wu An-An Liu Xu Li jia-Wei tu Juan Kong Ling-Ling Yang jian-Hong jia Chuan Wang Bin Hu Zhi-Xiong Xie Dai-Wen Pang The Institute for Advanced Studies College of Chemistry and Molecular SciencesCollege of Life SciencesHubei Key Laboratory of Cell HomeostasisWuhan UniversityWuhan 430072China Research Center for Analytical Sciences College of ChemistryState Key Laboratory of Medicinal Chemical BiologyTianjin Key Laboratory of Biosensing and Molecular RecognitionFrontiers Science Center for New Organic MatterFrontiers Science Center for Cell Responsesand Haihe Laboratory of Sustainable Chemical TransformationsNankai UniversityTianjin 300071China

Biosynthesized semiconductor quantum dots(QDs) have bright fluorescence,adjustable particle sizes,and environmental friendliness,endowing them with convenience and potential for biological *** to the unclear mechanism of the cellular environment on the live-cell synthesis of QDs,it is still difficult to regulate their optical ***,the critical role of the intracellular redox environment in regulating the fluorescence properties of biosynthesized CdSe QDs in Staphylococcus aureus(***) has been *** glutathione peroxidase(GPx) activity directly affects the intracellular H_(2)O_(2) produced in the SeO_(3)^(2-) reduction,which further manipulates the glutathione redox cycle to determine the content of low-valence *** a result,the fluorescence intensity of the synthesized CdSe QDs increases by 60% in the GPx overexpressed *** cellular redox potential that is controlled by the GSH redox cycle provides the driving force for the reduction of SeO_(3)^(2-),facilitating the synthesis of CdSe QDs in *** *** proposed mechanism of the cellular redox state provides a new perspective for regulating the synthesis of semiconductor nanomaterials in live cells.

关键词： redox H_(2)O_(2) peroxidase quantum dot Staphylococcus aureus

Thioredoxin pathway regulated live-cell synthesis of CdSe quantum dots in Saccharomyces cerevisiae

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Science China Chemistry 2024年第11期67卷 3851-3860页

作者： Xu Li Cai-Qin Wu jia-Wei tu Juan Kong Ling-Ling Yang Zhi-Xiong Xie Dai-Wen Pang College of Chemistry and Molecular Sciences The Institute for Advanced StudiesCollege of Life SciencesWuhan UniversityWuhan 430072China Research Center for Analytical Sciences College of ChemistryState Key Laboratory of Medicinal Chemical BiologyTianjin Key Laboratory of Biosensing and Molecular RecognitionFrontiers Science Center for New Organic MatterFrontiers Science Center for Cell Responsesand Haihe Laboratory of Sustainable Chemical TransformationsNankai UniversityTianjin 300071China

Currently, the application of synthetic biology to artificially manipulate and utilize organisms for the synthesis of desired products such as nanomaterials with excellent fluorescence properties is attracting considerable attention. However, it is still difficult to obtain designed products efficiently due to insufficient knowledge of the biosynthetic mechanisms. The thioredoxin(TRX) and glutathione(GSH) pathways are generally conserved thiol-reductase systems that protect organisms from oxidative stress and are involved in selenium(Se) metabolism. In this study, we revealed the pivotal role of cytoplasmic TRX pathway in regulating the metabolism of Na_(2)SeO_(3) during the live-cell synthesis of cadmium-selenium quantum dots(Cd Se QDs) in Saccharomyces cerevisiae by regulating the expression level of genes related to TRX pathway and measuring the intracellular content of selenocysteine(Se Cys). The determination of Se Cys metabolism in yeast with GSH pathway-related genes deleted demonstrated that the TRX pathway played a more significant role in Se Cys metabolism than GSH pathway. A 6.4-fold enhancement in the synthetic yield of Cd Se QDs was achieved through the overexpression of TRX pathway-related genes,improvement of synthetic procedure, and supplementation of GSH based on the understanding of biological *** the mechanism of CdSe QDs live-cell synthesis facilitates the precise manipulation of biological processes for the synthesis of inorganic nanomaterials.

关键词： thioredoxin glutathione quantum dot live-cell synthesis selenium metabolism Saccharomyces cerevisiae

Designer cell-self-implemented labeling of microvesicles in situ with the intracellular-synthesized quantum dots

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Science China Chemistry 2020年第4期63卷 448-453页

作者： Ling-Hong Xiong jia-Wei tu Ya-Nan Zhang Ling-Ling Yang Ran Cui Zhi-Ling Zhang Dai-Wen Pang College of Chemistry and Molecular Sciences State Key Laboratory of VirologyInstitute for Advanced Studiesand Wuhan Institute of BiotechnologyWuhan UniversityWuhan 430072China State Key Laboratory of Medicinal Chemical Biology Tianjin Key Laboratoryof Biosensing and Molecular RecognitionResearch Center for Analytical Sciencesand College of ChemistryNankai UniversityTianjin 300071China

Cell-derived microvesicles(MVs) are secreted from almost all kinds of mammalian cells into the extracellular space, and play crucial roles in intercellular communication and transporting biomolecules between cells. However, there is a great challenge for visualizing and monitoring of MVs’ bio-behaviors due to the limitations of existing labeling methods. Herein, we report the first paradigm of designer cell-self-implemented labeling of MVs secreted from living mammalian MCF-7 cells in situ using the intracellular-synthesized fluorescent quantum dots(QDs) during the formation of MVs. By elaborately coupling intracellular biochemical reactions and metabolism pathways, the MCF-7 cells can be illuminated brightly by intracellular-biosynthesized fluorescent CdSe QDs. Simultaneously, intracellular-synthesized QDs can be in situ encapsulated by the secreted MVs budding from the plasma membrane of the fluorescing cells to label the MVs with an efficiency of up to 89.9%. The whole labeling process skillfully combines designer precise cell-tuned intricate synthesis of CdSe QDs with mild in-situ labeling via cell-selfimplementation just after feeding the cell with suitable chemicals, which is structure-or function-nondestructive and much more straightforward and milder than those by chemical conjugation or indirect encapsulation with conventional fluorogenic labels.

关键词： in situ labeling live cell synthesis cell-derived microvesicles quantum dot cell-self-implementation

Synthesis and Crystal Structure of N-cyclopropyl-9 -(3,4-dicholophenyl)-1,2,3,4,5,6,7,8,9,10-decahydroacridine -1,8-dione under Microwave Irradiation

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Chinese Journal of Structural Chemistry 2005年第12期24卷 1457-1461页

作者： FENG You-jian jia Run-Hong tu Shu-jiang ZHANG Xiao-Jin jiaNG Bo ZHANG Yan ZHANG Jun-Yong Department of Chemistry Xuzhou Normal University Key Laboratory of Biotechnology on Medical Plant Xuzhou Jiangsu 221116 China

The N-cyclopropyl-9-（3,4-dicholophenyl）- 1,2,3,4,5,6,7,8,9,10-decahydroacri- dine-1,8-dione was synthesized by the reaction of 1,3-cyclohexanedione, N-cyclopropylamine and 3,4-dicholoaldehyde in water and glycol under microwave irradiation. Its crystal structure was determined by single-crystal X-ray diffraction analysis. It possesses P212121 space group, with a = 9.9103（5）, b = 13.3597（8）, c = 14.5633（8）A, V= 1928.16（18）A3 ,Mr = 402.30, Z = 4, Dc= 1.386 g/cm^3, 2 = 0.7107A,μ（MoKα）=0.354mm^-1 and F （000） = 840. The structure was refined to R = 0.0280 and wR = 0.0757. In the structure, the pyridine ring adopts a boat conformation.

关键词： acridine synthesis microwave irradiation crystal structure