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1.
Biomaterials ; 212: 1-16, 2019 08.
Artigo em Inglês | MEDLINE | ID: mdl-31100479

RESUMO

The residual bacteria in the second revision surgery caused by infection would further lead to the failure of the implantation. Pathogenic bacteria adhesion to an implant surface not only interfere the functions of bone-formation related cells, but also activate the host immune system, thus resulting in inflammation and osteogenesis inhibition. Thus, to fabricate multifunctional (antibacterial, anti-inflammation and pro-osteogenesis) titanium implants is essential to address this issue. In this work, hybrid magnesium/zinc-metal organic framework (Mg/Zn-MOF74) coating was constructed on alkali-heat treated titanium (AT) surface. The hybrid Mg/Zn-MOF74 coating displayed good stability and its stability was related to the content of Zn2+. The MOF74-modified samples were sensitive to bacterial acid microenvironment and displayed strong antibacterial ability against both Escherichia coli and Staphylococcus aureus due to the degradation of MOF74 coating, leading to alkaline microenvironment (about pH 8.0) and degradation products (2,5-dihydroxyterephthalic acid and Zn2+). The coating also showed good early anti-inflammatory property to native Ti substrates. In vivo results further verified that AT-Mg/Zn3 implants had high antibacterial and anti-inflammatory properties at early stage of implantation, and greatly improved new bone formation around implants both at non-infected and infected femur sites.


Assuntos
Infecções Bacterianas/prevenção & controle , Regeneração Óssea/efeitos dos fármacos , Magnésio/farmacologia , Estruturas Metalorgânicas/farmacologia , Próteses e Implantes , Titânio/farmacologia , Zinco/farmacologia , Fosfatase Alcalina/metabolismo , Animais , Animais Recém-Nascidos , Antibacterianos/farmacologia , Anti-Inflamatórios/farmacologia , Morte Celular/efeitos dos fármacos , Colágeno/metabolismo , Escherichia coli/efeitos dos fármacos , Escherichia coli/ultraestrutura , Concentração de Íons de Hidrogênio , Camundongos , Testes de Sensibilidade Microbiana , Osteogênese/efeitos dos fármacos , Ácidos Ftálicos/química , Células RAW 264.7 , Ratos , Staphylococcus aureus/efeitos dos fármacos , Staphylococcus aureus/ultraestrutura , Difração de Raios X
2.
Materials (Basel) ; 12(8)2019 Apr 18.
Artigo em Inglês | MEDLINE | ID: mdl-31003521

RESUMO

The feasibility and effectivity of recycling waste rubber and waste plastic (WRP) into asphalt binder as a waste treatment approach has been documented. However, directly blending WRP with asphalt binder brings secondary environmental pollution. Recent research has shown that the addition of WRP into asphalt binder may potentially improve the workability of asphalt binder without significantly compromising its mechanical properties. This study evaluates the feasibility of using the additives derived from WRP as a multifunctional additive which improves both the workability and mechanical properties of asphalt binder. For this purpose, WRP-derived additives were prepared in laboratory. Then, three empirical characteristics-viscosity, rutting factor, fatigue life were analyzed. Fourier transform infrared spectroscopy (FTIR) and differential scanning calorimetry (DSC) were employed to evaluate the effect of WRP-derived additive on the workability and chemical and mechanical properties of base binder. The dispersity of WRP-derived additive inside asphalt binder was also characterized using fluorescence microscope (FM). Results from this study showed that adding WRP-derived additive increases the workability of base binder. The WRP-derived additive appears positive on the high- and low- temperature performance as well as the fatigue life of base binder. The distribution of the WRP-derived additive inside base binder was uniform. In addition, the modification mechanism of WRP-derived additive was also proposed in this paper.

3.
Bioact Mater ; 3(1): 110-117, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29744448

RESUMO

High corrosion kinetics and localised corrosion progress are the primary concerns arising from the clinical implementation of magnesium (Mg) based implantable devices. In this study, a binary Mg-lithium (Li) alloy consisting a record high Li content of 14% (in weight) was employed as model material aiming to yield homogenous and slow corrosion behaviour in a simulated body fluid, i.e. minimum essential medium (MEM), in comparison to that of generic Mg alloy AZ31 and biocompatible Mg-0.5Zn-0.5Ca counterparts. Scanning electron microscopy examination reveals single-phase microstructural characteristics of Mg-14Li (ß-Li), whilst the presence of insoluble phases, cathodic to α-Mg matrix, in AZ31 and Mg-0.5Zn-0.5Ca. Though slight differences exist in the corrosion kinetics of all the specimens over a short-term time scale (no longer than 60 min), as indicated by potentiodynamic polarisation and electrochemical impedance spectroscopy, profound variations are apparent in terms of immersion tests, i.e. mass loss and hydrogen evolution measurements (up to 7 days). Cross-sectional micrographs unveil severe pitting corrosion in AZ31 and Mg-0.5Zn-0.5Ca, but not the case for Mg-14Li. X-ray diffraction patterns and X-ray photoelectron spectroscopy confirm that a compact film (25 µm in thickness) consisting of lithium carbonate (Li2CO3) and calcium hydroxide was generated on the surface of Mg-14Li in MEM, which contributes greatly to its low corrosion rate. It is proposed therefore that the single-phase structure and formation of protective and defect-free Li2CO3 film give rise to the controlled and homogenous corrosion behaviour of Mg-14Li in MEM, providing new insights for the exploration of biodegradable Mg materials.

4.
Molecules ; 20(12): 21178-92, 2015 Nov 27.
Artigo em Inglês | MEDLINE | ID: mdl-26633320

RESUMO

A highly porous metal-organic framework (Cu-TDPAT), constructed from a paddle-wheel type dinuclear copper cluster and 2,4,6-tris(3,5-dicarboxylphenylamino)-1,3,5-triazine (H6TDPAT), has been tested in Ullmann and Goldberg type C-N coupling reactions of a wide range of primary and secondary amines with halobenzenes, affording the corresponding N-arylation compounds in moderate to excellent yields. The Cu-TDPAT catalyst could be easily separated from the reaction mixtures by simple filtration, and could be reused at least five times without any significant degradation in catalytic activity.


Assuntos
Aminas/química , Cobre/química , Compostos Organometálicos/química , Triazinas/química , Catálise , Estrutura Molecular
5.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 12): m1818-9, 2011 Dec 01.
Artigo em Inglês | MEDLINE | ID: mdl-22199598

RESUMO

In the crystal structure of the title coordination polymer, {[Zn(2)(C(24)H(18)N(4)O(10))(H(2)O)(4)]·H(2)O}(n), the mol-ecular building block (MBB), viz [Zn(2)(CO(2))(4)(H(2)O)(4)], comprises two Zn(II) cations, each bridged by three carboxyl-ate groups from different ligand mol-ecules. These two Zn(II) cations exhibit different coordination environments: a distorted trigonal-pyramidal coordination, as an inter-mediate, is formed by the two coordinated water mol-ecules and three carboxyl-ate groups, and a distorted octa-hedral geometry defined by three water mol-ecules and three carboxyl-ate groups, in which two carboxyl-ate groups from the same side of the clip glycoluril ring and one water mol-ecule are bidentate bridging, whereas others are monodentate units. Every ligand mol-ecule connects four MBBs, thus forming a three-dimensional structure. Extensive intra- and inter-molecular O-H⋯O hydrogen bonding is observed.

6.
Acta Crystallogr Sect E Struct Rep Online ; 67(Pt 10): m1406, 2011 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-22064841

RESUMO

In the crystal structure of the title coordination polymer, {[Zn(2)(C(17)H(8)O(10))(C(3)H(7)NO)(2)]·C(3)H(7)NO}(n), the mol-ecular build-ing block (MBB), viz. {Zn(2)(CO(2))(4)(C(3)H(7)NO)(2)}, comprises two zinc atoms, each bridged by three carboxyl-ate groups. These two Zn atoms exhibit different coordination environments: a distorted coordination intermediate between trigonal-pyramidal, and square-pyramidal formed by the two coordinated dimethyl-formamide mol-ecules and three carboxylate groups, and a distorted tetra-hedral coordination defined by carboxy-late groups of which three are bidentate bridging and the fourth is a monodentate ligand. Thus, each ligand connects four MBBs, forming the three-dimensional polymer.

7.
Acta Crystallogr Sect E Struct Rep Online ; 66(Pt 7): m829, 2010 Jun 23.
Artigo em Inglês | MEDLINE | ID: mdl-21587742

RESUMO

In the title coordination polymer, [Zn(C(8)H(4)O(4))(C(5)H(5)N)(2)](n), the Zn(II) atom, located on a twofold rotation axis, is tetra-coordinated by two monodentate O atoms from two different carboxyl-ate groups and two pyridyl N atoms, forming a distorted tetra-hedral geometry. The Zn(II) atoms are bridged by terephthalate ligands, generating an infinite zigzag chain along [101].

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