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Wang K.,University of Sichuan | Wang K.,Hong Kong University of Science and Technology | Leng Y.,Hong Kong University of Science and Technology | Lu X.,Key Laboratory of Advanced Technologies of Materials | And 2 more authors.
Journal of Materials Science: Materials in Medicine

This study numerically studies absorption of human serum albumin (HSA) and basic protein lysozyme (LSZ) on crystallographic planes of octacalcium phosphate (OCP), an essential bioactive calcium phosphate. The molecular simulations include constructing atomic structure of OCP crystallographic planes and representative segments of HSA and LSZ with three different initiate orientations respect to OCP planes. The simulation reveals the dynamic process of the protein absorption. The absorption behavior of proteins is quantified by the interaction energy between proteins and OCP planes and the strain energy of proteins in absorption. The results show that absorption interaction energy of basic LSZ is higher than that of acidic HSA, which indicates that LSZ is more favorable to adsorb onto OCP surface than HSA. The interaction energies change with the OCP crystallographic planes, the trend of changes for both proteins are similar, that is OCP (001) > OCP (111) > OCP (110) > OCP (100), which is corrected with surface energy variation of crystallographic planes. The strain energy strongly depends on the orientations of the proteins before absorption, but weakly depends on crystallographic planes. The simulation results provide useful significant information for predicting/ designing interface between bioceramic materials and organic tissues as well as for understanding the mechanism of the osteoinductivity at an atomic level. © Springer Science+Business Media, LLC 2012. Source

Zhang B.,Key Laboratory of Advanced Technologies of Materials | Chen J.,Georgia Institute of Technology | Jin L.,Key Laboratory of Advanced Technologies of Materials | Deng W.,Key Laboratory of Advanced Technologies of Materials | And 7 more authors.
ACS Nano

Wireless traffic volume detectors play a critical role for measuring the traffic-flow in a real-time for current Intelligent Traffic System. However, as a battery-operated electronic device, regularly replacing battery remains a great challenge, especially in the remote area and wide distribution. Here, we report a self-powered active wireless traffic volume sensor by using a rotating-disk-based hybridized nanogenerator of triboelectric nanogenerator and electromagnetic generator as the sustainable power source. Operated at a rotating rate of 1000 rpm, the device delivered an output power of 17.5 mW, corresponding to a volume power density of 55.7 W/m3 (Pd = P/V, see Supporting Information for detailed calculation) at a loading resistance of 700 ω The hybridized nanogenerator was demonstrated to effectively harvest energy from wind generated by a moving vehicle through the tunnel. And the delivered power is capable of triggering a counter via a wireless transmitter for real-time monitoring the traffic volume in the tunnel. This study further expands the applications of triboelectric nanogenerators for high-performance ambient mechanical energy harvesting and as sustainable power sources for driving wireless traffic volume sensors. © 2016 American Chemical Society. Source

Wang H.,Southwest Jiaotong University | Wang H.,Key Laboratory of Advanced Technologies of Materials | King R.B.,University of Georgia

Abstract Cyclooctatetraene has been found experimentally to form the perpendicular binuclear sandwich compounds (η3,η3-C8H8)2Ni2 and [η5,5-(Me3Si)2C8H6]2Ti2. The entire series of such cyclooctatetraene sandwich compounds (C8H8)2M2 has now been examined by density functional theory. Bis(pentahapto) folded η5,η5-C8H8 rings are found in the lowest energy (C8H8)2M2 derivatives of the early transition metals Ti, V, Cr, and Mn. The lowest energy Ti derivative is the singlet spin state structure (η5,η5-C8H8)2Ti2 containing two such rings with geometry close to the experimental structure for the known silylated derivative [η5,5-(Me3Si)2C8H6]2Ti2. The lowest energy (C8H8)2M2 structures for V, Cr, and Mn are (η5,η5-C8H8)M2(η3,η3-C8H8) having metal-metal multiple bonds of various orders. For (η5,η5-C8H8)V2(η3,η3-C8H8) singlet and triplet spin state structures are approximately equal in energy. For (η5,η5-C8H8)M2(η3,η3-C8H8) (M = Cr, Mn) the triplet state structures are the lowest energy structures. The lowest energy (C8H8)2M2 structures for the later transition metals Fe, Co, Ni are triplet spin state structures for Fe and Co and a singlet spin state structure for Ni. All three such (η3,η3-C8H8)2M2 (M = Fe, Co, Ni) structures have two bis(trihapto) η3,η3-C8H8 rings containing uncomplexed CC double bonds. © 2015 Elsevier Ltd. Source

Wang Z.,Key Laboratory of Advanced Technologies of Materials | Wang K.,University of Sichuan | Lu X.,Key Laboratory of Advanced Technologies of Materials | Li M.,Shandong University | And 6 more authors.
Journal of Biomedical Materials Research - Part A

Bone morphology protein-2 (BMP-2) encapsulated chitosan/chondrotin sulfate nanoparticles (CHI/CS NPs) are developed to enhance ectopic bone formation on biphasic calcium phosphate (BCP) scaffolds. BMP-2 contained CHI/CS NPs were prepared by a simple and mild polyelectrolyte complexation process. It does not involve harsh organic solvents and high temperature, and therefore retain growth factors activity. These NPs were immobilized on BCP scaffolds, and realize the sustained release of growth factors from the scaffolds. The bare BCP scaffolds, NP loaded scaffolds (BCPNP), and NP loaded and polydopamine coated scaffolds (BCP-Dop-NP) were seeded with bone marrow stroma cells (BMSC) to evaluate the osteoinductivity of the scaffolds. BMSC culture results indicate that all scaffolds favor cell adhesion, proliferation, differentiation. Afterwards, the bare BCP, BCP-NP, and BCP-Dop-NP scaffolds were implanted into rabbits intramuscularly to evaluate the ectopic bone formation of scaffolds. In vivo results indicate that the BCP-NP and BCP-Dop-NP scaffolds enhance more ectopic bone formation than the bare BCP scaffolds. Both the in vitro and in vivo results demonstrate that BMP-2 encapsulated polysaccharide NPs are effective to improve the osteoinductivity of the scaffolds. In addition, BCP-NP scaffolds induce more bone formation than BCP-Dop-NP scaffolds. This is because BCP-NP scaffolds harness the intrinsic osteoinductivity BCP and BMP-2, whereas BCP-Dop-NP scaffolds have polydopamine coatings that inhibit the surfaces biological features of BCP scaffolds, and therefore weaken the bone formation ability of scaffolds. © 2014 Wiley Periodicals, Inc. Source

Wang H.,Southwest Jiaotong University | Wang H.,Key Laboratory of Advanced Technologies of Materials | Wang H.,University of Georgia | Sun S.,Southwest Jiaotong University | And 2 more authors.
New Journal of Chemistry

Reactions of cyclooctatetraene with iron carbonyls under various conditions give not only the monomeric (η4-C8H8)Fe(CO)3 but three C8H8Fe2(CO)6 isomers and one C8H8Fe2(CO)5 isomer. Density functional theory on the C8H8Fe2(CO)6 system shows the trans-(η4,η4-C8H8)Fe2(CO)6 isomer to be the lowest energy isomer. The cis-(η3,η3-C8H8)Fe2(CO)6 isomer with an Fe-Fe bond and an uncomplexed CC double bond in the C8H8 ring lying ∼11 kcal mol-1 in energy above trans-(η4,η4-C8H8)Fe2(CO)6 appears to correspond to one of the metastable C8H8Fe2(CO)6 isomers obtained under relatively mild conditions. However, the cis-(η4,η4-C8H8)Fe2(CO)6 structure without an Fe-Fe bond suggested for the other metastable isomer appears to be a high-energy structure with a large imaginary vibrational frequency. Following the corresponding normal mode leads to cis-(η3,η3-C8H8)Fe2(CO)6. For C8H8Fe2(CO)5 the two lowest energy structures are singly bridged cis-C8H8Fe2(CO)4(μ-CO) structures differing only by a 22.5°rotation of the C8H8 ring around the central Fe2 unit. One of these structures is the experimental C8H8Fe2(CO)5 structure. The closeness in energy of these two C8H8Fe2(CO)5 structures is consistent with the experimentally observed fluxionality of this molecule in the NMR spectrum at low temperatures. The unsaturated C8H8Fe2(CO)n (n = 4, 3) structures obtained by further decarbonylation of C8H8Fe2(CO)5 retain the bridging bis(tetrahapto) or bis(pentahapto) C8H8 rings of C8H8Fe2(CO)5 and provide examples of structures with formal Fe=Fe double bonds with the lowest energy such structures having triplet rather than singlet spin states. Viable carbonyl-rich (η2,η2-C8H8)Fe2(CO)8 and (η4,η2-C8H8)Fe2(CO)7 structures represent possible intermediates in the formation of the various C8H8Fe2(CO)n (n = 6, 5) species from cyclooctatetraene and iron carbonyls. © The Royal Society of Chemistry and the Centre National de la Recherche Scientifique. Source

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