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ABSTRACT: By means of the density functional theory calculations, two C88(D2:35)-based endohedral fullerenes, Lu3C2@C88(D2:35) and Lu3N@C88(D2:35) which encapsulate tri-lutetium carbide and tri-lutetium nitride cluster were investigated. For the cores in Lu3C2@C88 and Lu3N@C88, the trivalent C2 and N respectively template a butterfly-shaped endohedral moiety and a planar tri-lutetium cluster within the same D2-symmetric C88 cage. Moreover, Lu3N@C88 - D2 has a closed-shell electronic structure but for LuC3C2@C88 - D2, it owns an unpaired electron mainly localized on the internal Lu3C2 cluster. These results clearly showed that the core unit C2(3) as well as N3- play an important role in constructing molecular structures and electronic features of metallofullerenes. Furthermore, the electrochemical redox potentials, and vibrational frequencies of the two endofullerenes agree well with our experimental results. The electronic structures, ionization energies, electron affinities, inner clusters' dynamic motions of them have been predicted to further disclose the characters of these two metallofullerenes.
Journal of Nanoscience and Nanotechnology 03/2012; 12(3):2254-60. · 1.56 Impact Factor
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ABSTRACT: Self-assembled monolayers (SAMs) of trithiocyanuric acid (TTCA) on Au(111) surfaces are investigated by scanning tunneling microscopy (STM), cyclic voltammetry, and density functional theory calculation (DFT). The SAM exhibits a wormlike disordered structure from 1.0 V to 260 mV vs RHE (reversible hydrogen electrode). At 260 mV, an irreversible disorder–order phase transformation occurs and results in an ordered striped phase. High resolution STM images and DFT calculations suggest that TTCA molecules are parallel to each other within the stripes, which prompts the π–π stacking interactions between the molecules. Each molecule adsorbs vertically on the substrate via two S atoms and one heterocyclic N atom anchoring on the surface at the bridge sites and the top site, respectively. This adsorption geometry promises the SAM with good stability (binding energy 3.27 eV) and free reactive S terminals. The high stability and free S terminals of the TTCA SAM makes it a promising scaffold for applications in molecular electronics and chem/bio sensors.
08/2011;
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ABSTRACT: Stereoisomerism is a fundamental chemistry issue and has been intensively investigated because of its importance in organic chemistry, biology, and pharmacology. Molecules with freely rotatable single bonds have many interconvertable conformers. Herein, we report the surface-adsorption-induced conformer resolution by employing azobenzene-3,3-dicarboxylic acid (ADA-33) as a model compound. Two linear assembly phases composed of trans conformers on a highly oriented pyrolytic graphite (HOPG) surface are observed by scanning tunneling microscopy. With the codeposition with 1-octanoic acid (OA), only one trans conformer of ADA-33 can be recognized by OA to form a two-component assembly with alternately arranged ADA-33 and OA stripes, which can be attributed to the epitaxial assembly of ADA-33 and OA on the HOPG surface, and weak hydrogen bonding exists between conformer I and OA molecules. The results are of significance with respect to the discrimination and resolution of conformers on a solid surface and provide molecular insights into the coadsorption assembly on the surface.
Langmuir 07/2011; 27(16):9994-9. · 4.19 Impact Factor
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ABSTRACT: We report the preparation, isolation, and spectroscopic characterizations of a novel endofullerene Lu3C2@C88, where a planar trimetallic carbide cluster Lu3C2 is encapsulated by D2-symmetric C88 cage. Meanwhile, the trimetallic nitride endofullerene Lu3N@C88 was also isolated and characterized for comparison. The results revealed that both metal carbide Lu3C2 and metal nitride Lu3N share the same D2-symmetric C88 cage. Theoretical studies revealed that the internal moieties supply the C88 cage with six electrons in both Lu3N@C88 and Lu3C2@C88 cases; however, Lu3N@C88 has a closed-shell electronic structure and Lu3C2@C88 owns an unpaired electron localized on the internal [Lu3C2]6+ moiety. The different molecular electronic structures of Lu3C2@C88 and Lu3N@C88 lead to distinct differences on both the UV−vis absorption spectral features and their electrochemical redox properties.
12/2010;
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Tai-Shan Wang,
Lai Feng, Jing-Yi Wu,
Wei Xu,
Jun-Feng Xiang,
Kai Tan,
Yi-Han Ma,
Jun-Peng Zheng,
Li Jiang,
Xin Lu,
Chun-Ying Shu,
Chun-Ru Wang
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ABSTRACT: The endohedral fullerene Sc3NC@C80-Ih has been synthesized and characterized; it has an unprecedented planar quinary cluster in a fullerene cage. It is also the first chemical compound in which the presence of an unprecedented (NC)3− trianion has been disclosed. The fascinating intramolecular dynamics in Sc3NC@C80-Ih enables the whole molecule to display high polarity and promising ferroelectricity. This finding inspires the possibility that such a planar quinary cluster may be useful in constructing many other endohedral fullerenes.
11/2010;
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Tai-Shan Wang,
Lai Feng, Jing-Yi Wu,
Wei Xu,
Jun-Feng Xiang,
Kai Tan,
Yi-Han Ma,
Jun-Peng Zheng,
Li Jiang,
Xin Lu,
Chun-Ying Shu,
Chun-Ru Wang
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ABSTRACT: The endohedral fullerene Sc(3)NC@C(80)-I(h) has been synthesized and characterized; it has an unprecedented planar quinary cluster in a fullerene cage. It is also the first chemical compound in which the presence of an unprecedented (NC)(3-) trianion has been disclosed. The fascinating intramolecular dynamics in Sc(3)NC@C(80)-I(h) enables the whole molecule to display high polarity and promising ferroelectricity. This finding inspires the possibility that such a planar quinary cluster may be useful in constructing many other endohedral fullerenes.
Journal of the American Chemical Society 11/2010; 132(46):16362-4. · 9.91 Impact Factor
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Tai-Shan Wang,
Ning Chen,
Jun-Feng Xiang,
Bao Li, Jing-Yi Wu,
Wei Xu,
Li Jiang,
Kai Tan,
Chun-Ying Shu,
Xin Lu,
Chun-Ru Wang
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ABSTRACT: For the first time, we have produced the stable compound Sc(4)C(2)@C(80)-I(h) and characterized it as a metal carbide endofullerene by FTIR and Raman spectroscopies in combination with DFT calculations. Furthermore, DFT calculations have demonstrated that this molecule has a Russian-doll-type structure, C(2)@Sc(4)@C(80).
Journal of the American Chemical Society 10/2009; 131(46):16646-7. · 9.91 Impact Factor
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ABSTRACT: This study was aimed to explore fgfr3 gene expression in leukemic cells and its clinical significance. The expression levels of fgfr3 mRNA in 4 leukemic cell lines and bone marrow samples from 96 patients with leukemia and 14 controls were assayed by RT-PCR. 96 patients with leukemia included 36 cases of acute myeloid leukemia (AML), 29 cases of acute lymphoblastic leukemia (ALL), 31 cases of chronic myelogenous leukemia (CML). The results indicated that fgfr3 gene could be detected in both K562 and U937 cell lines, but not in HL-60 and SHI-1 cell lines. The positive expression rates of fgfr3 mRNA in AL and CML were 46.15% and 51.61% respectively, and were higher than that in control (14.29%, p < 0.05). The positive expression rates of fgfr3 mRNA in AML and ALL were 44.44% and 48.28% respectively, and were higher than that in control (p < 0.05). The increased level of fgfr3 mRNA had a positive correlation with high white blood cell count of > or = 20 x 10(9)/L (p < 0.05). Higher fgfr3 mRNA expression positively correlated with fuse genes of bcr/abl in ALL (r = 0.151, p < 0.05). The expression of fgfr3 gene in AL was not related with chromosome abnormality. In conclusion, the over expression of fgfr3 gene exists in AL and CML patients, it suggests that fgfr3 gene may be partially involved in leukemogenesis.
Zhongguo shi yan xue ye xue za zhi / Zhongguo bing li sheng li xue hui = Journal of experimental hematology / Chinese Association of Pathophysiology 09/2008; 16(4):738-41.
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ABSTRACT: It has always been assumed that purge-and-trap (P&T) method is only used for the analysis of volatile organic compounds (VOCs) in aqueous samples. In this paper, a novel P&T preconcentrator has been developed for the determination of trace amounts of ammonium ion in high-salinity water samples by ion chromatography (IC). Method performance is evaluated as a function of concentration of assistant purging material, purging time, and flow rate. Under the optimum P&T conditions with the purified nitrogen gas at flow rate 40 mL/min for 15.0 min at 40 degrees C, the overall collection efficiency is independent of the concentration of ammonium over the range 1.2-5.9 microM. The enrichment factor (EF) of ammonium correlates the ratio of the sample volume to the acceptor solution volume in the trap vessel, providing potentially unlimited increase of the ammonium signal. Our results indicate that environmental samples with low levels of ammonium in matrices with high concentrations of sodium can be easily analyzed and the detection limit down to 75 nM (1.35 ppb) level, corresponding to picomole of ammonia in the injected sample. Calibration graph was constructed with ammonium standards ranging from 0.05 to 6.0 microM and the linearity of the present method was good as suggested by the square of correlation coefficients being better than 0.997. Thus, we have demonstrated that the P&T-IC method allows the routine determination of ammonium ion in seawater samples without cation interferences.
Journal of Chromatography 05/2008; 1188(2):69-74. · 4.53 Impact Factor
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Wei Liu,
Zhi-Min Cui,
Qiang Liu,
Dong-Wei Yan, Jing-Yi Wu,
Hui-Juan Yan,
Yun-Long Guo,
Chun-Ru Wang,
Wei-Guo Song,
Yun-Qi Liu,
Li-Jun Wan
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ABSTRACT: PPA nanobelts were synthesized using nanocopper particles as catalysts in the gas-phase polymerization of phenylacetylene. This route offers several advantages over the conventional method: copper is used instead of expensive noble metal catalysts; gas-phase reaction avoids the use of toxic organic solvents; highly crystalline PPA nanobelt arrays can be produced. PPA nanobelts were characterized by XRD, SEM, TEM, AFM, and DSC techniques. The PPA nanobelts were highly crystalline and have the cis-specific conformation. The I−V characteristics of a single nanobelt with different doped levels were characterized. All three belts show semiconductor features. An undoped PPA belt has the largest insulating gap (about 10 V). Doping the nanobelts with iodine significantly decreases the gap. The belt that underwent 30 min of iodine doping is nearly a conductor.
Journal of the American Chemical Society 11/2007; 129(43):12922-3. · 9.91 Impact Factor
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ABSTRACT: Poly (N-isopropylacrylamide) (PNIPAAm) hydrogels possess a lower critical solution temperature (LCST) at around 32 degrees C. When the external temperature is raised above the LCST, the hydrogels experience abrupt and drastic shrinkage. This unique property makes them very useful for biomedical applications such as on-off switches for modulated drug delivery and tissue engineering. The aim of this work was to study the potential of using PNIPAAm hydrogels for protein delivery, and to obtain basic understandings of the protein-gel interactions as well as their effect on protein loading and release. PNIPAAm gels were synthesized with different crosslinker contents. The effects of crosslinker content, in vitro release temperature, protein loading level and molecular size as well as temperature cycling on protein release from PNIPAAm gels were examined. Greater amount of BSA was loaded using gels fabricated with lower crosslinker contents and loading solution with higher concentrations of BSA. An incomplete release of encapsulated BSA from the gels was observed in all cases. Enhanced mass transfer created by oscillating swelling-deswelling in response to temperature cycling across the LCST and lowering in vitro release temperature did not promote BSA release because of strong BSA-gel interactions. Evidence for the residual BSA in the gels after in vitro release was provided by dyeing the gels with protein determination reagent and shift in the LCST of the gels. In contrast, insulin release was much faster and more complete when compared to BSA because of its smaller size. The protein-gel interactions were analysed by investigating the LCST of, and state of water in, the blank and protein-loaded hydrogels.
Journal of Controlled Release 03/2005; 102(2):361-72. · 5.73 Impact Factor
