General chemistry, physical chemistry, Chimie générale, chimie physique, Crystallography, Cristallographie cristallogenèse, Nanotechnologies, nanostructures, nanoobjects, Nanotechnologies, nanostructures, nanoobjets, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure, proprietes mecaniques et thermiques, Condensed matter: structure, mechanical and thermal properties, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Couche mince, Thin films, Photoluminescence, Procédé sol gel, Sol-gel process, Préparation, Preparation, Preparación, Silicium, Silicon, Spectre transformée Fourier, Fourier transform spectra, Si, Fourier transform infrared spectrum, MgxZn1_xO thin films, Photocatalytic activity, and Photoluminescence spectrum

Magnesium doped zinc oxide (MgxZn1-xO) thin films were synthesized on silicon substrate through sol-gel process. Mg0.15Zn0.85O thin films were annealed at 500-800 °C and ZnO, Mg0.1 Zn0.9O, Mg0.05Zn0.95O thin films were annealed at 600 °C for 60 min, respectively. The results show that all the samples are of a hexagonal wurtzite structure of ZnO. The surface morphology is strongly dependent on mean grain size and surface fluctuation. Fourier transform infrared spectra reveal that the vibration peak at 420 cm-1 is of the intrinsic lattice absorption of ZnO. The peak at 1083 cm-1 belongs to Si—O—Si asymmetric stretching vibration. Photoluminescence spectra show that the ultraviolet emission (365-400 nm) and the broad visible emission (469-569 nm) are observed. In particular, Mg0.05Zn0.95O thin film annealed at 600 °C exhibits the highest photocatalytic activity, degrading MO by almost 85.8% after 180 min illumination. The photocatalytic activity of the thin film is a synergistic effect defined by grain size, roughness factor, oxygen defects and amorphous MgO.

Inorganic chemistry, Chimie minérale, Crystallography, Cristallographie cristallogenèse, Metallurgy, welding, Métallurgie, soudage, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés et matériaux magnétiques, Magnetic properties and materials, Diamagnétisme, paramagnétisme et superparamagnétisme, Diamagnetism, paramagnetism and superparamagnetism, Arrangements de spin dans les matériaux magnétiquement ordonnés (incluant les études par neutrons et électrons à spin polarisé, la diffusion de rayons x synchrotroniques, etc.), Spin arrangements in magnetically ordered materials (including neutron and spin-polarized electron studies, synchrotron-source x-ray scattering, etc.), Autres propriétés intrinsèques des matériaux magnétiquement ordonnés, Magnetically ordered materials: other intrinsic properties, Moments à saturation et susceptibilités magnétiques, Saturation moments and magnetic susceptibilities, Etudes de matériaux magnétiques particuliers, Studies of specific magnetic materials, Ferrimagnétiques, Ferrimagnetics, Activation thermique, Thermal activation, Termoactivación, Addition chrome, Chromium additions, Cristal hexagonal, Hexagonal crystals, Diffraction RX, XRD, Dopage, Doping, Double échange, Double exchange, Energie activation, Activation energy, Ferrimagnétisme, Ferrimagnetism, Ferromagnétique, Ferromagnetic materials, Material ferromagnético, Haute énergie, High energy, Alta energía, Interaction échange, Exchange interactions, Matériau ferrimagnétique, Ferrimagnetic materials, Matériau ferromagnétique, Ordre magnétique, Magnetic ordering, Paramagnétisme, Paramagnetism, Petit polaron, Small polaron, Pequeño polarón, Phénomène transport, Transport processes, Polycristal, Polycrystals, Propriété transport, Transport properties, Propiedad transporte, Propriété électrique, Electrical properties, Refroidissement, Cooling, Réaction état solide, Solid state reaction, Reacción estado sólido, Réseau hexagonal, Hexagonal lattices, Réseau monoclinique, Monoclinic lattices, Réseau orthorhombique, Orthorhombic lattices, Susceptibilité magnétique, Magnetic susceptibility, Traitement thermique, Heat treatments, 7530C, 7550C, 7550G, YMnO3, Cr-doped manganite, Double-exchange interaction, and X-ray diffraction

Half Cr-doped YMn0.5Cr0.5O3 polycrystalline has been synthesized by means of a standard solid-state reaction method. Powder X-ray diffraction gives evidence that the sample is a single phase of orthorhombic (Pbnm) or monoclinic (P21/c) structure as observed for other doped manganites, rather than the hexagonal structure as YMnO3. Upon cooling, the magnetic susceptibility increases sharply at TC ∼ 75 K, indicating a magnetic ordering occurs. The detailed analysis on the paramagnetic behavior at higher temperatures reveals that the low-temperature order is a ferrimagnetic state. The electrical transport properties show an insulator behavior dominated by the adiabatic small polaron hopping mechanism with high thermal activation energy. The results indicate that the ferromagnetic double exchange (DE) interaction is unreasonable in Cr-doped manganites.

Electronics, Electronique, Condensed state physics, Physique de l'état condensé, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Etat condense: structure electronique, proprietes electriques, magnetiques et optiques, Condensed matter: electronic structure, electrical, magnetic, and optical properties, Propriétés et matériaux magnétiques, Magnetic properties and materials, Phénomènes de magnétotransport, matériaux pour le magnétotransport, Magnetotransport phenomena, materials for magnetotransport, Manganites, Composition chimique, Chemical composition, Conduction petit polaron, Small polaron conduction, Conduction saut, Hopping conduction, Conductivité électrique, Electrical conductivity, Densité électron, Electron density, Diffraction RX, XRD, Dopage, Doping, Double échange, Double exchange, Energie activation, Activation energy, Manganite, Manganites, Manganito, Perovskites, Réseau cubique, Cubic lattices, Susceptibilité magnétique, Magnetic susceptibility, Transition ferromagnétique antiferromagnétique, Ferromagnetic-antiferromagnetic transitions, Verre spin, Spin glasses, Cr-doped manganite, Double-exchange interaction, Ferrimagnetism, Spin glass, and X-ray diffraction

We report an investigation on the evolution of structural, magnetic and transport properties in double-doped manganites Y0.5+ySr0.5-yMn1-yCryO3 (0≤y≤0.5), remaining eg electron density (x=0.5) unchanged. From a pseudo-cubic perovskite structure for Y0.5Sr0.5MnO3 with y=0, powder X-ray diffraction patterns demonstrate that Cr3+ substitution on the Mn-site leads to a tetragonal distortion, which increases with the doping level y. The temperature dependence of magnetic susceptibility shows that the magnetic state at low temperatures evolves from an antiferromagnetic-spin-glass state for y=0, undergoing a ferromagnetic-spin-glass state, finally to a ferrimagnetic state for y=0.5. The electrical transport properties of all samples show an insulator behavior dominated by the small polaron hopping mechanism and the activation energy increases significantly along with y. Consequently, the enhancement of ferromagnetic component in the Y0.5+ySr0.5-yMn1-yCryO3 series may be attributed to the anisotropic ferromagnetic superexchange interactions of Mn3+ ions collaborating with the ordered arrangement of Mn3+/Cr3+ ions, rather than the double exchange interaction via eg-electron hopping process.

Biotechnology, Biotechnologies, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Biotechnologie, Biotechnology, Echafaudage, Scaffold, Andamiaje, Fibrine, Fibrin, Fibrina, Hétérogreffe, Heterograft, Heteroinjerto, In vivo, Ligament, Ligamento, Os, Bone, Hueso, Protéine morphogénétique osseuse, Bone morphogenetic protein, Proteína morfogenética ósea, Tendon, Tendón, Anterior cruciate ligament, Fibrin glue, Recombined bone xenograft, and Tendon-bone interface healing

Fibrin glue combined with bone morphogenetic protein (BMP) and recombined bone xenograft (RBX), were compared to evaluate their effect on the tendon―bone interface healing. The interface of fibrin glue-BMP developed new cartilage but the new bone was thinner whereas the interface of RBX had large areas of chondrocyte-like cells, bone formation and an immature neo-enthesis structure. At 12 weeks, bone mineral density of RBX group (152 ± 52 cm3) and fibrin glue-BMP group (109 ± 13 cm3) was calculated by micro-computed tomography. The ultimate load of fibrin glue-BMP group (60 ± 18 and 51 ± 14 N) and RBX group (65 ± 21 and 57 ± 15 N) was shown by biomechanics at 6 and 12 weeks. RBX thus has an advantage on accelerating tendon―bone interface healing.

Orthopedics traumatology, Orthopédie, traumatologie, Rheumatology, Rhumatologie, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Pathologie osteoarticulaire, Diseases of the osteoarticular system, Adipocyte, Adipocito, Cartilage, Cartílago, Cellule souche, Stem cell, Célula primitiva, Gélatine, Gelatin, Gelatina, Microsphère, Microsphere, Microsfera, Rhumatologie, Rheumatology, Reumatología, Régénération, Regeneration, Regeneración, Réparation, Repair, Reparación, Tissu adipeux, Adipose tissue, Tejido adiposo, Cellules souches adipeuses, Chitosan, Microsphères, and Réparation du cartilage

Objectif. - Notre étude a eu pour but l'évaluation de la capacité de microsphères (MS) hybrides composées de MS de gélatine chargées en transforminggrowth factor-beta (TGF-β1) et de MS de chitosan, à augmenter la différenciation in vitro de cellules souches du tissu adipeux (CSA) en chondrocytes dans un pellet de culture, et la capacité de réparer in vivo des lésions cartilagineuses à l'aide de pellets formés d'un mélange de CSA et de MS hybrides-TGF. Méthodes. - La morphologie des MS à libération contrôlée a été visualisée avec un microscope électronique à balayage. Leurs propriétés mécaniques ont aussi été étudiées. La libération in vitro du TGF-β1 a été évaluée par une méthode Elisa. L'expression protéique du collagène de type Il a été évaluée par Western Blot. De plus, une étude préliminaire sur la réparation cartilagineuse in vivo a été effectuée. Résultats. - L'analyse de la différenciation chondrocytaire des CSA dans chaque type de microsphère a montré une expression du collagène de type Il significativement supérieure dans le groupe MS hybrides-TGF par rapport au groupe MS gélatine-TGF. L'analyse des propriétés mécaniques a montré que les MS hybrides étaient supérieures aux MS de gélatine. Les analyses histologiques in vivo ont montré que le pellet du mélange CSA/MS hybrides-TGF stimule la réparation des lésions cartilagineuses de manière plus efficace que les autres groupes. Conclusion. - Notre étude démontre que le pellet du mélange CSA/MS hybrides-TGF peut constituer une méthode facile et efficace pour la reconstruction tissulaire du cartilage tant in vitro que in vivo.

Gerontology geriatrics, Gérontologie, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Vertebres: anatomie et physiologie, organisme dans son ensemble ou etude de plusieurs organes ou systemes, Vertebrates: anatomy and physiology, studies on body, several organs or systems, Développement. Métamorphose. Mue. Sénescence, Development. Metamorphosis. Moult. Ageing, Vertebrata, Cartilage, Cartílago, Cellule souche, Stem cell, Célula primitiva, Chondrogenèse, Chondrogenesis, Condrogénesis, Facteur croissance transformant β1, Transforming growth factor β1, Factor crecimiento transformante β1, Libération, Release, Liberación, Mammalia, Sénescence, Senescence, Senescencia, Tissu, Tissue, Tejido, Adipose-derived stem cells, Cartilage tissue engineering, Chitosan, Gelatin, and Microspheres

Background: Articular cartilage has a limited self-regenerative capacity, and tissue engineering is a promising solution to the problem of cartilage damage. Objective: The aim of this study was to evaluate the effect of hybrid microspheres (MS) composed of transforming growth factor (TGF)-β1-loaded gelatin MS and chitosan MS on enhancement of the differentiation of adipose-derived stem cells (ASCs) into chondrocytes in pellet culture. Methods: In vitro TGF-β1 release was evaluated by an enzyme-linked immunosorbent assay. The content of DNA and glycosaminoglycans (GAGs) was tested by biochemical methods. In addition, quantitative PCR was used to analyze the expression of collagen II and aggrecan. Results: Increased proliferation of ASCs was observed in the hybrid TGF-β1-loaded MS in comparison to the TGF-β1-loaded gelatin MS. The chondrogenic differentiation of ASCs in both constructs was evaluated, and GAG content and the gene expression of collagen II and aggrecan were significantly higher in the hybrid TGF-β1-loaded MS than in the TGF-β1-loaded gelatin MS. Conclusions: Enhanced differentiation of ASCs by hybrid TGF-β1-loaded MS may provide an easy and effective way to construct tissue-engineered cartilage.

General chemistry, physical chemistry, Chimie générale, chimie physique, Metallurgy, welding, Métallurgie, soudage, Sciences exactes et technologie, Exact sciences and technology, Physique, Physics, Domaines interdisciplinaires: science des materiaux; rheologie, Cross-disciplinary physics: materials science; rheology, Science des matériaux, Materials science, Traitements de surface, Surface treatments, Prototypage rapide, Rapid prototyping, Prototipificación rápida, Traitement surface, Surface treatments, Apatite, Collagen, Hybrid, Rapid prototyping (RP), and Scaffold

The objective of this experiment is to produce a novel scaffold composed of poly (lactic-co-glycolic acid) (PLGA)/p-tricalciumphosphate (p-TCP) skeleton covered with apatite/collagen sponge. BMSCs were used to evaluate the cell behavior on the hybrid scaffold. Cell morphology on the surfaces of PLGA/p-TCP skeleton and PLGA/p-TCP skeleton with apatite/collagen sponge composite coating was studied by scanning electron microscopy (SEM). Cell proliferation was assessed by cell number counting. Differentiated BMSCs function was monitored by measuring alkaline phosphates activity of the cells. These results demonstrated that the apatite/collagen sponge composite coating could improve cell proliferation and ALP activity of the hybrid scaffolds and increase its hydrophilicity after hybridization. The experiment suggested that the PLGA/p-TCP skeleton with apatite/collagen sponge composite coating is promising as a candidate 3D substrate for bone tissue engineering.

Medicine

Adipose-derived stem cells (ASCs) appear to be a useful stem cell population, which has been shown to possess multipotentiality. The aim of this study was to evaluate the utility of ASCs in tissue-engineered cartilage using a hybrid scaffold from fibrin-modified PLGA scaffold. ASCs were isolated from rabbit adipose tissue. The PLGA scaffold was prepared by low-temperature deposition technology and the hybrid scaffold was fabricated by a freeze-drying method. When ASCs were seeded onto fibrin-modified PLGA scaffold in vitro, enhanced cellular viability was observed compared to unmodified PLGA scaffold. The analysis of proteoglycan and collagen II revealed that fibrin-modified scaffold succeeded in inducing ASCs to differentiate into chondrocytes in vitro. A preliminary study on cartilage regeneration was also performed in vivo. Observation of histology and immunoblotting demonstrated that ASCs containing the hybrid scaffold promoted cartilage regeneration in the defects of articular cartilage much better than other groups. These results indicated that ASCs containing the hybrid scaffold are a more effective way to potentially enhance articular cartilage regeneration.

EXTRACELLULAR matrix, MESENCHYMAL stem cells, CHONDROGENESIS, MESENCHYME, and COLLAGEN

Background: Cartilage formation from self-assembling mesenchymal stem cells (MSCs) in vitro recapitulate important cellular events during mesenchymal condensation that precedes native cartilage development. The goal of this study was to investigate the effects of cartilaginous extracellular matrix (ECM) components and culture regimen on cartilage formation by self-assembling human MSCs in vitro and in vivo. Methods: Human bone marrow-derived MSCs (hMSCs) were seeded and compacted in 6.5-mm-diameter transwell inserts with coated (type I, type II collagen) or uncoated (vehicle) membranes, at different densities (0.5 × 106, 1.0×106, 1.5 × 106 per insert). Pellets were formed by aggregating hMSCs (0.25 × 106) in round-bottomed wells. All tissues were cultured for up to 6 weeks for in vitro analyses. Discs (cultured for 6, 8 or 10 weeks) and pellets (cultured for 10 weeks) were implanted subcutaneously in immunocompromised mice to evaluate the cartilage stability in vivo. Results: Type I and type II collagen coatings enabled cartilage disc formation from self-assembling hMSCs. Without ECM coating, hMSCs formed dome-shaped tissues resembling the pellets. Type I collagen, expressed in the prechondrogenic mesenchyme, improved early chondrogenesis versus type II collagen. High seeding density improved cartilage tissue properties but resulted in a lower yield of disc formation. Discs and pellets exhibited compositional and organizational differences in vitro and in vivo. Prolonged chondrogenic induction of the discs in vitro expedited endochondral ossification in vivo. Conclusions: The outcomes of cartilage tissues formed from self-assembling MSCs in vitro and in vivo can be modulated by the control of culture parameters. These insights could motivate new directions for engineering cartilage and bone via a cartilage template from self-assembling MSCs. [ABSTRACT FROM AUTHOR]

HYPOXEMIA, BONE growth, CHONDROGENESIS, HOMEOSTASIS, METAZOA, and TRANSCRIPTION factors

Oxygen availability is a critical signal for the proper development of many tissues. The transcription factor hypoxia-inducible factor (HIF) plays an important role in maintenance of oxygen homeostasis in all metazoans. Numerous growth and transcription factors have been implicated in the development of the skeletal system. Many of the factors that are up-regulated during hypoxia are downstream of HIF activation. Recent work has demonstrated that HIF has a critical function in cartilage and bone development. We summarize current understanding of the role of HIF in bone and cartilage development. [ABSTRACT FROM AUTHOR]