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2.
Int J Nanomedicine ; 14: 9497-9512, 2019.
Artigo em Inglês | MEDLINE | ID: mdl-31819446

RESUMO

Background: Critical-sized bone defects raise great challenges. Zein is of interest for bone regeneration, but it has limited ability to stimulate cell proliferation. In this regard, a poly (aspartic acid) (PAsp)-zein hybrid is promising, as PAsp can promote rat bone marrow stromal cell (rBMSCs) proliferation and osteogenic differentiation. This research aimed to develop electrospun PAsp-modified zein nanofibers to realize critical-sized bone defects repair. Methods: Three groups of PAsp-modified zein nanofibers were prepared, they were PAsp grafting percentages of 0% (zein), 5.32% (ZPAA-1), and 7.63% (ZPAA-2). Using rBMSCs as in vitro cell model and SD rats as in vivo animal model, fluorescence staining, SEM, CCK-8, ALP, ARS staining, µCT and histological analysis were performed to verify the biological and osteogenic activities for PAsp-modified zein nanofibers. Results: As the Asp content increased from 0% to 7.63%, the water contact angle decreased from 129.8 ± 2.3° to 105.5 ± 2.5°. SEM, fluorescence staining and CCK-8 assay showed that ZPAA-2 nanofibers had a superior effect on rBMSCs spreading and proliferation than did zein and ZPAA-1 nanofibers, ALP activity and ARS staining showed that ZPAA-2 can improve rBMSCs osteogenic differentiation. In vivo osteogenic activities was evaluated by µCT analysis, HE, Masson and immunohistochemical staining, indicating accelerated bone formation in ZPAA-2 SD rats after 4 and 8 weeks treatment, with a rank order of ZPAA-2 > ZPAA-1 > zein group. Moreover, the semiquantitative results of the Masson staining revealed that the maturity of the new bone was higher in the ZPAA-2 group than in the other groups. Conclusion: Electrospun PAsp-modified zein can provide a suitable microenvironment for osteogenic differentiation of rBMSCs, as well as for bone regeneration; the optimal membrane appears to have a PAsp grafting percentage of 7.63%.


Assuntos
Regeneração Óssea/fisiologia , Nanofibras/química , Peptídeos/química , Zeína/química , Fosfatase Alcalina/metabolismo , Animais , Diferenciação Celular , Proliferação de Células , Forma Celular , Células-Tronco Mesenquimais/citologia , Osteogênese/efeitos dos fármacos , Ratos Sprague-Dawley , Crânio/diagnóstico por imagem , Microtomografia por Raio-X
3.
Inorg Chem ; 56(15): 9343-9352, 2017 Aug 07.
Artigo em Inglês | MEDLINE | ID: mdl-28718656

RESUMO

The title compound was synthesized by a reaction of the elemental educts in a corundum crucible at 1200 °C under an Ar atmosphere. The excess of Ga used in the initial mixture served as a flux for the subsequent crystal growth at 600 °C. The crystal structure of Yb4Ga24Pt9 was determined from single-crystal X-ray diffraction data: new prototype of crystal structure, space group C2/m, Pearson symbol mS74, a = 7.4809(1) Å, b = 12.9546(2) Å, c = 13.2479(2) Å, ß = 100.879(1)°, V = 1260.82(6) Å3, RF = 0.039 for 1781 observed reflections and 107 variable parameters. The structure is described as an ABABB stacking of two slabs with trigonal symmetry and compositions Yb4Ga6 (A) and Ga12Pt6 (B). The hard X-ray photoelectron spectrum (HAXPES) of Yb4Ga24Pt9 shows both Yb2+ and Yb3+ contributions as evidence of an intermediate valence state of ytterbium. The evaluated Yb valence of ∼2.5 is in good agreement with the results obtained from the magnetic susceptibility measurements. The compound is a bad metallic conductor.

4.
J Biomed Mater Res B Appl Biomater ; 105(8): 2641-2652, 2017 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-27783470

RESUMO

The aim of this study was to investigate and compare the surface characteristics and initial bioactivity of ceria-stabilized zirconia/alumina nanocomposite (NANOZR) with those of yttria-stabilized zirconia (3Y-TZP) and pure titanium (CpTi) following the use of three surface modification methods; polishing, sandblasting/acid-etching (SB-E) and electrochemical deoxidation (ECD). Physical properties including surface morphology, chemical composition, X-ray diffraction, surface wettability, surface roughness, and hardness were measured. Osteoblast-like MC3T3-E1 cells were used to examine cell morphology and attachment to the surfaces of the materials. ECD treated NANOZR (NANOZR-E) showed a well-arranged, self-organized microporous surface structure with significantly low contact angles when compared with the other specimens (p < 0.05). NANOZR-E also demonstrated a slight decrease in monoclinic phase content (-4.4 wt %). The morphology and attachment of MC3T3-E1 cells on NANOZR-E were similar to those on polished and SBE-treated CpTi surfaces. Higher cell affinity was observed on NANOZR-E when compared with ECD treated 3Y-TZP. The findings of this study indicate the effectiveness of the novel technique, ECD, in the formation of a microporous surface on NANOZR when compared with both CpTi and 3Y-TZP. Moreover, this method also appears to improve the biological activity of NANOZR during the initial stage. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 105B: 2641-2652, 2017.


Assuntos
Técnicas Eletroquímicas , Teste de Materiais , Osteoblastos/metabolismo , Titânio , Molhabilidade , Zircônio , Animais , Linhagem Celular , Camundongos , Osteoblastos/citologia , Porosidade , Titânio/química , Titânio/farmacologia , Zircônio/química , Zircônio/farmacologia
5.
J Synchrotron Radiat ; 24(Pt 1): 296-301, 2017 01 01.
Artigo em Inglês | MEDLINE | ID: mdl-28009570

RESUMO

In this study an analysis strategy towards using the resonant inelastic X-ray scattering (RIXS) technique more effectively compared with X-ray absorption spectroscopy (XAS) is presented. In particular, the question of when RIXS brings extra information compared with XAS is addressed. To answer this question the RIXS plane is analysed using two models: (i) an exciton model and (ii) a continuum model. The continuum model describes the dipole pre-edge excitations while the exciton model describes the quadrupole excitations. Applying our approach to the experimental 1s2p RIXS planes of VO2 and TiO2, it is shown that only in the case of quadrupole excitations being present is additional information gained by RIXS compared with XAS. Combining this knowledge with methods to calculate the dipole contribution in XAS measurements gives scientists the opportunity to plan more effective experiments.

6.
Proc Natl Acad Sci U S A ; 113(40): 11148-11151, 2016 10 04.
Artigo em Inglês | MEDLINE | ID: mdl-27647884

RESUMO

Optically transparent conducting materials are essential in modern technology. These materials are used as electrodes in displays, photovoltaic cells, and touchscreens; they are also used in energy-conserving windows to reflect the infrared spectrum. The most ubiquitous transparent conducting material is tin-doped indium oxide (ITO), a wide-gap oxide whose conductivity is ascribed to n-type chemical doping. Recently, it has been shown that ionic liquid gating can induce a reversible, nonvolatile metallic phase in initially insulating films of WO3 Here, we use hard X-ray photoelectron spectroscopy and spectroscopic ellipsometry to show that the metallic phase produced by the electrolyte gating does not result from a significant change in the bandgap but rather originates from new in-gap states. These states produce strong absorption below ∼1 eV, outside the visible spectrum, consistent with the formation of a narrow electronic conduction band. Thus WO3 is metallic but remains colorless, unlike other methods to realize tunable electrical conductivity in this material. Core-level photoemission spectra show that the gating reversibly modifies the atomic coordination of W and O atoms without a substantial change of the stoichiometry; we propose a simple model relating these structural changes to the modifications in the electronic structure. Thus we show that ionic liquid gating can tune the conductivity over orders of magnitude while maintaining transparency in the visible range, suggesting the use of ionic liquid gating for many applications.

7.
Thromb Res ; 131(6): e270-3, 2013 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-23571140

RESUMO

INTRODUCTION: Quercetin is widely distributed in plants and has been reported to have effects of anti-inflammation and anti-thrombosis. In this study, we evaluated the protective effect of quercetin on LPS-induced experimental DIC in rabbits, and tried to clarify its mechanism against DIC. MATERIALS AND METHODS: LPS-induced DIC model in rabbits was established through continuous infusion of 100 ug · kg(-1) · h(-1) LPS for a period of 6h. Six groups were divided: quercetin-treated groups (0.5, 1.0, and 2.0 mg·kg(-1) · h(-1), respectively), LPS-control group, heparin-control group (100 IU · kg(-1) · h(-1)), and saline-control group. APTT, PT, and plasma FIB level were measured, the plasma levels of ALT, BUN, and TNF-α were detected, and the activity of Protein C and ATIII was recorded. RESULTS: A continuous injection of LPS induced a gradual impairment of hemostatic parameters, a rise in plasma level of TNF-α, and damage in renal and hepatic function. The intravenous administration of quercetin significantly attenuated the increase of APTT, PT, ALT, BUN, and TNF-α, and the decrease of plasma FIB level and activity of Protein C and ATIII. CONCLUSION: Quercetin may have a protective effect against LPS-induced DIC in rabbits through anti-inflammation and anticoagulation.


Assuntos
Antioxidantes/uso terapêutico , Coagulação Intravascular Disseminada/tratamento farmacológico , Quercetina/uso terapêutico , Alanina Transaminase/sangue , Animais , Nitrogênio da Ureia Sanguínea , Coagulação Intravascular Disseminada/sangue , Coagulação Intravascular Disseminada/induzido quimicamente , Lipopolissacarídeos , Masculino , Tempo de Tromboplastina Parcial , Tempo de Protrombina , Coelhos , Fator de Necrose Tumoral alfa/sangue
8.
Ultrasound Med Biol ; 36(2): 227-33, 2010 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-20045591

RESUMO

This study was designed to characterize the changes in the peak systolic longitudinal, circumferential and radial strains by using 2-D strain echocardiography in patients with coronary artery stenosis without segmental wall motion abnormalities on conventional 2-D echocardiography. 2D strain echocardiography was performed in 44 patients with different degrees of coronary artery stenosis. Myocardial longitudinal, circumferential and radial strain profiles were obtained and peak systolic strain values were measured. The peak systolic longitudinal strain was significantly reduced in myocardial segments subtended by coronary arteries with greater than 75% stenosis when compared with those subtended by coronary artery with less than 75% stenosis and those in control. Sensitivity and specificity were 74% and 72%, respectively, for peak systolic longitudinal strain to predict segments subtended by coronary arteries with greater than 75% stenosis (cutoff value--17.7%; area under the receiver operating characteristic curve, 0.825). There were no significant differences in circumferential and radial strains among myocardial segments subtended by coronary arteries with greater than 75% stenosis and those with less than 75% stenosis and in control. In conclusion, our study suggests that analysis of long-axis cardiac function by using the 2-D strain echocardiography may help to identify the myocardial segments subtended by coronary arteries with severe stenosis.


Assuntos
Estenose Coronária/diagnóstico por imagem , Ecocardiografia/métodos , Contração Miocárdica/fisiologia , Adulto , Idoso , Estenose Coronária/fisiopatologia , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Variações Dependentes do Observador , Padrões de Referência
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