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  • Author or Editor: Jian Zhang x
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Abstract  

We introduce a new visual analytic approach to the study of scientific discoveries and knowledge diffusion. Our approach enhances contemporary co-citation network analysis by enabling analysts to identify co-citation clusters of cited references intuitively, synthesize thematic contexts in which these clusters are cited, and trace how research focus evolves over time. The new approach integrates and streamlines a few previously isolated techniques such as spectral clustering and feature selection algorithms. The integrative procedure is expected to empower and strengthen analytical and sense making capabilities of scientists, learners, and researchers to understand the dynamics of the evolution of scientific domains in a wide range of scientific fields, science studies, and science policy evaluation and planning. We demonstrate the potential of our approach through a visual analysis of the evolution of astronomical research associated with the Sloan Digital Sky Survey (SDSS) using bibliographic data between 1994 and 2008. In addition, we also demonstrate that the approach can be consistently applied to a set of heterogeneous data sources such as e-prints on arXiv, publications on ADS, and NSF awards related to the same topic of SDSS.

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Abstract

Large-scale scientific projects have become a major impetus of scientific advances. But few studies have specifically analyzed how those projects bolster scientific research. We address this question from a scientometrics perspective. By analyzing the bibliographic records of papers relevant to the Sloan Digital Sky Survey (SDSS), we found that the SDSS helped scientists from many countries further develop their own research; investigators initially formed large research groups to tackle key problems, while later papers involved fewer authors; and the number of research topics increased but the diversity of topics remains stable. Furthermore, the entropy analysis method has proven valuable in terms of analyzing patterns of research topics at a macroscopic level.

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Abstract  

To investigate the radio impurity in the radiolysis of 18F-FDG at high radiodose and radioconcentrated solutions and develop methods of repurification. The radiolysis of 18F-FDG was analyzed by TLC. The radio-impurity was confirmed by biodistribution and small animal PET/CT studies. 18F-FDG was unstable at high radioconcentrition over 37 GBq/mL or under basic condition. TLC, biodistribution and PET/CT all indicated that the main autoradiolysis byproduct was free fluoride ion. The radiolyzed 18F-FDG was repurified by solid-phase extraction (SPE) column. The repurified 18F-FDG had a radiochemical purity (RCP) of over 99% and significantly lower bone uptake than that was before repurification (P = 0.0003). There was a positive correlation between the recovery yield and the purity of 18F-FDG (R 2 = 0.66).

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Abstract  

The concentrations of up to 11 elements in subcellular fractions of human brain (normal and malignant tumor) have been determined by a combination of gradient centrifugation and INAA methods. Samples of human brain were homogenized in a glass homogenizer tube, the homogenate was separated into nuclei, mitochondrial, myelin, synaptosome fractions, and these fractions were then analyzed using the INAA method. The discussions of elemental subcellular distributions in human brain malignant tumor are presented in this paper.

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Abstract  

The need of reliable production of N-succinimidyl 4-[18F]fluorobenzoate ([18F]SFB), a versatile 18F-labeled prosthetic group for protein labeling, has increased dramatically due to the easy availability of proteins or their engineered derivatives for targeted molecular imaging. A module-assisted radiosynthesis of [18F]SFB was developed using a three-step, one-pot procedure and ethyl 4-(trimethylammonium)benzoate triflate (1) as the starting material. The radiochemical transformations were carried out in a general-purpose, custom-made module and streamlined by an anhydrous deprotection strategy using t-BuOK/DMSO. After HPLC-purification, [18F]SFB was synthesized in radiochemical yields of 20–30% (n > 10, not decay-corrected) and excellent radiochemical and chemical purities (>98%). The total synthesis and purification time required is ~90 min. Using the purified [18F]SFB, three 18F-labeled proteins, bovine serum albumin (BSA), chicken egg albumin (CEA) and transferrin, were synthesized in yields of 61.0–79.5%. The 18F-Annexin V for apoptosis imaging was also produced in 5% radiolabeling yield and >95% radiochemical purity.

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Journal of Radioanalytical and Nuclear Chemistry
Authors: Shuye Yang, Xuebin Wang, Haixun Guo, Jian Liu, Fenglong Wang, and Xianzhong Zhang

Abstract  

Mixed ligand fac-tricarbonyl complex of [99mTc(CO)3-DMSA-MIBI] has been prepared starting from the precursor [99mTc(OH2)3(CO)3]+. The complex can be obtained in good yield and purity in a two-step procedure by first attaching meso-2,3-dimercaptosuccinic acid (DMSA, HOOCCH(SH)CH(SH)COOH) with [99mTc(OH2)3(CO)3]+, followed by addition of MIBI [tetrakis-2-methoxyisobutylisonitrile (CH3OC(CH3)2CH2-N≡C) copper(I) tetrafluoroborate] solution. The complex was characterized by TLC and HPLC and was studied by means of octanol-water partition coefficient, electrophoresis, stability in vitro, and normal mice experiment. Biodistribution in mice demonstrated that the complex showed higher myocardial uptake after 0.5-hour p.i. The ratios of heart/liver (%ID/g) in the case of 99mTc(CO)3-DMSA-MIBI was higher (1.88) than that observed in case of 99mTc-MIBI1 (0.93) after 0.5-hour p.i. (P<0.05). Results showed that the complex may be developed to a novel myocardial perfusion-imaging agent.

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JPC - Journal of Planar Chromatography - Modern TLC
Authors: Yuping Wang, Dongyuan Wang, Jie Wang, Zhili Xiong, Hongxia Zhang, Gaohong She, Jian Li, and Shengtao Xiao

A new AMD instrument made in our laboratory is described in this paper. The main advantages of the instrument are very low cost both of construction and in use. Compared with ascending development in conventional instruments, a laboratory-made horizontal sandwich chamber is used for development, and, with the help of a series of special accessories, no obvious mobile phase remains in the distributor after each step; this saves a large amount of solvent. All the components of the instrument are easy to obtain, so the average worker in a chemical laboratory could construct all the instrument except the control unit. An application of the instrument is described; the results obtained were satisfactory.

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Abstract  

Systematically complicated technique used for preparing high-intensity (more than 8.0 GBq/cm2)241Am -source by a new enamel technique is presented. High intensity241Am -sources with activities ranging from 3.7 to 37 GBq have been made by this new technique. The activity and photon output have been measured. The results were compared with the data reported by the Radiochemical Centre Amersham in their specification. The photon output of241Am -source produced by us meets the technical specification of241Am -sources produced by Amersham. Moreover, the highest intensity can reach 1789 mCi/cm2. The overall utilization ratio of241Am activity (59.5 keV) is 31.2%.

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Journal of Thermal Analysis and Calorimetry
Authors: Yanni Qi, Jian Zhang, Shujun Qiu, Lixian Sun, Fen Xu, Min Zhu, Liuzhang Ouyang, and Dalin Sun

Abstract  

Polyaniline/NiO (PANI/NiO) composites were synthesized by in situ polymerization at the presence of HCl (as dopant). FTIR, TEM and XRD were used to characterize the composites. Thermogravimetry (TG)–mass spectrometer (MS) and temperature modulated differential scanning calorimetry (TMDSC) were used to study the thermal stability, decomposition and glass transition temperature (T g) of the composites, respectively. FTIR and XRD results showed that NiO nanoparticles connected with PANI chains in the PANI/NiO composites. TEM results exhibited that the morphologies of PANI/NiO composites were mostly spherical, which were different from the wirelike PANI. TG–MS curves indicated that the products for oxidative degradation of both PANI and PANI/NiO composite were H2O, CO2, NO and NO2. TG curves showed that with NiO contents increased in PANI/NiO composites, thermal stability of PANI/NiO composites increased firstly and then decreased when the NiO content was higher than 66.2 wt%. T g of PANI/NiO composites also increased from 163.19 to 252.36 °C with NiO content increasing from 0 to 50 wt%, and then decreased with NiO content increasing continuously.

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Abstract

A three-dimensional lithium-based metal–organic framework Li2(2,6-NDC) (2,6-NDC = 2,6-naphthalene dicarboxylate) has been synthesized solvothermally and characterized by X-ray powder diffraction, elemental analysis, FT-IR spectroscopy, thermogravimetry and mass spectrometer analysis (TG–MS). The framework has exceptional stability and is stable to 863 K. The thermal decomposition characteristic of this compound was investigated through the TG–MS from 293 to 1250 K. The molar heat capacity of the compound was measured by temperature modulated differential scanning calorimetry (TMDSC) over the temperature range from 195 to 670 K for the first time. The thermodynamic parameters such as entropy and enthalpy versus 298.15 K based on the above molar heat capacity were calculated.

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