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Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Radiotherapie. Traitement instrumental. Physiotherapie. Reeducation. Readaptation, orthophonie, crenotherapie. Traitement dietetique et traitements divers (generalites), Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects), Technologie. Biomatériaux. Equipements. Matériel. Appareillage, Technology. Biomaterials. Equipments. Material. Instrumentation, Cardiotonique, Cardiotonic agent, Cardiotónico, Génie biomédical, Biomedical engineering, Ingeniería biomédica, Stimulant dopaminergique, Dopamine agonist, Estimulante dopaminérgico, Acide ascorbique, Ascorbic acid, Acido ascórbico, Configuration électrode, Electrode configuration, Configuración electrodo, Contact métal oxyde, Metal oxide contact, Contacto metal óxido, Dopamine, Dopamina, Graphite, Grafito, Réaction catalytique, Catalytic reaction, Reacción catalítica, Simultanéité, Simultaneity, Simultaneidad, Système redox, Redox system, Sistema redox, Séparation, Separation, Separación, Technique, Técnica, Voltammétrie, Voltammetry, and Voltametría

In this paper, a new method was introduced to separate dopamine and ascorbic acid simultaneously. When a graphite electrode was modified with nanosized TiO2 powder, it exerted little influence on the redox behavior of dopamine, but led to the anodic potential of ascorbic acid to move negatively which enlarged the anodic separation potential between dopamine and ascorbic acid to some extent. Better separation could be achieved with bare C and TiO2 modified electrode at higher scan rate. The catalytical ability of nanosized metal oxide on the voltammetric behavior of dopamine and ascorbic acid was discussed as well.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Chirurgie (generalites). Transplantations, greffes d'organes et de tissus. Pathologie des greffons, Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases, Chirurgie orl et maxillofaciale. Chirurgie dentaire. Orthodontie, Head and neck surgery. Maxillofacial surgery. Dental surgery. Orthodontics, Chirurgie maxillofaciale. Chirurgie dentaire. Orthodontie, Maxillofacial surgery. Dental surgery. Orthodontics, Génie biomédical, Biomedical engineering, Ingeniería biomédica, Animal, Article synthèse, Review, Artículo síntesis, Biomatériau, Biomaterial, Cellule souche, Stem cell, Célula primitiva, Chirurgie, Surgery, Cirugía, Culture cellulaire, Cell culture, Cultivo celular, Homme, Human, Hombre, Maxillofacial, Maxilofacial, Ostéogenèse, Osteogenesis, Osteogénesis, Protéine morphogénétique osseuse, Bone morphogenetic protein, Proteína morfogenética ósea, Reconstruction, Reconstrucción, Transplantation, and Trasplantación

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Radiotherapie. Traitement instrumental. Physiotherapie. Reeducation. Readaptation, orthophonie, crenotherapie. Traitement dietetique et traitements divers (generalites), Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects), Technologie. Biomatériaux. Equipements. Matériel. Appareillage, Technology. Biomaterials. Equipments. Material. Instrumentation, Génie biomédical, Biomedical engineering, Ingeniería biomédica, Analyse structurale, Structural analysis, Análisis estructural, Analyse thermogravimétrique, Thermogravimetric analysis, Apatite hydroxylée, Hydroxyapatite, Hidroxiapatito, Calcium phosphate, Calcio fosfato, Effet température, Temperature effect, Efecto temperatura, Phase cristalline, Crystalline phase, Fase cristalina, Projection plasma, Plasma spraying, Proyección plasma, Reconstruction, Reconstrucción, Transformation phase, Phase transformation, and Transformación fase

Commercial hydroxyapatite (HAP) powders were quenched from 1500°C to room temperature and reheated at different temperatures by a program controlled SiC-heated furnace to investigate the reconstruction behavior of quenched HAP powder in air. X-ray diffractometer (XRD) and Fourier-transformed infrared (FTIR) analysis were used to examine changes in crystalline phases and functional groups of quenched HAP powders at different temperatures. Weight changes of the quenched powders during heating were recorded by thermogravimetric analysis (TGA). The XRD results showed that the quenched HAP powder was composed of two crystalline phases of tetracalcium phosphate (TTCP) and α-tricalcium phosphate (αTCP). There was no other calcium phosphate phases to be traced. When quenched HAP powders were reheated, TTCP gradually reconstructed into HAP around 500°C and yield Ca(OH)2. αTCP did not convert to HAP at a temperature lower than 700°C but the transformation of αTCP to βTCP was observed during heating. αTCP reacted with Ca(OH)2, the product of reconstruction of TTCP, to form more HAP at temperatures over 700°C. In addition, the CO32- ion was incorporated into the lattice of the reconstructed HAP around 500°C. The intensity of CO32- ion in FTIR decreased as the temperature increased and totally disappeared around 900°C. Above 1000°C, reconstructed HAP lost OH ions and transformed into oxyhydroapatite.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Radiotherapie. Traitement instrumental. Physiotherapie. Reeducation. Readaptation, orthophonie, crenotherapie. Traitement dietetique et traitements divers (generalites), Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects), Maladies du système ostéoarticulaire. Traitement orthopédique, Diseases of the osteoarticular system. Orthopedic treatment, Lagomorpha, Mammalia, Système ostéoarticulaire pathologie, Diseases of the osteoarticular system, Sistema osteoarticular patología, Vertebrata, Amélioration, Improvement, Mejoría, Animal, Chondrocyte, Condrocito, Cicatrisation, Cicatrization, Cicatrización, Facteur croissance, Growth factor, Factor crecimiento, In vitro, In vivo, Lapin, Rabbit, Conejo, Membre inférieur, Lower limb, Miembro inferior, Multiplication cellulaire, Cell proliferation, Multiplicación celular, Ménisque, Semilunar cartilage, Menisco, Thérapie génique, Gene therapy, and Terapia génica

The meniscus plays important roles in the knee joint, including load transmission at the tibiofemoral articulation, shock absorption, lubrication, and stabilization of the knee joint, though its healing capacity remains limited. Meniscal healing requires the proliferation of meniscal fibrochondrocytes from either an intrinsic source at the site of injury or an extrinsic source from the blood supply or synovium. We have characterized the effects of various doses of nine growth factors on the meniscal fibrochondrocyte proliferation and collagen and non-collagen synthesis, and identified epidermal growth factor (EGF), transforming growth factor alpha (TGFα ), basic fibroblast growth factor (bFGF) and platelet derived growth factor AB (PDGF-AB) as candidate molecules to improve meniscal healing. The direct administration of the human recombinant growth factor protein is likely to be limited by the short biological half-life of these proteins and the rapid clearance of the injected proteins. We have therefore evaluated the feasibility of gene therapy and tissue engineering to deliver marker genes into the meniscus and found that direct and myoblast mediated ex viva gene transfer can be used to deliver high levels and persistent expression of these growth factors into the injured meniscus. This study will help in the development of strategies to improve meniscal healing using new innovative technologies such as gene therapy approaches.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Chirurgie (generalites). Transplantations, greffes d'organes et de tissus. Pathologie des greffons, Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases, Chirurgie orl et maxillofaciale. Chirurgie dentaire. Orthodontie, Head and neck surgery. Maxillofacial surgery. Dental surgery. Orthodontics, Chirurgie des voies aérodigestives supérieures, Surgery of the upper aerodigestive tract, Cavité buccale pathologie, Oral cavity disease, Cavidad bucal patología, Greffe, Graft, Injerto, Génie biomédical, Biomedical engineering, Ingeniería biomédica, Appareil circulatoire, Circulatory system, Aparato circulatorio, Autogreffe, Autograft, Autoinjerto, Cavité buccale, Oral cavity, Cavidad bucal, Homme, Human, Hombre, Mandibule, Mandible, Mandíbula, Microchirurgie, Microsurgery, Microcirugía, Propriété matériau, Properties of materials, Propiedad material, Reconstruction, Reconstrucción, Stade avancé, Advanced stage, Estadio avanzado, Tumeur maligne, Malignant tumor, Tumor maligno, Vascularisation, Vascularization, and Vascularización

Autogenous vascularized bone grafts in combination with microsurgical techniques have revolutionized mandibular reconstruction in oral cancer surgery. The vascularized bone graft carries its own blood supply, resists infection, and heals rapidly even in the irradiated bed. However, its use in advanced oral cancer patients is controversial due to the gloomy prognosis of these patients. Effective alloplastic materials such as titanium plate or tray for mandibular reconstruction is a reasonable alternative. These can easily be shaped and have sufficient structural rigidity to maintain the mandibular fragments in proper orientation. Likewise, it is a fast and reliable procedure which can obtain good oral function. However, its potential late exposure due to breakdown of overlying skin, especially after radiotherapy, is well documented. This paper discusses our experience to rescue the oral function after alloplastic material failure using the vascularized fibula osteocutaneous flap, in irradiated patients. All fibula osteocutaneous flaps survived. Symmetry and contour of the reconstructed mandible were judged to be good, and patients were able to eat without saliva drooling Donor-site morbidity was also low. From this clinical study, we believe that in advanced oral cancer, the titanium plate or tray is a useful adjunct for immediate mandibular reconstruction after surgical resection. The vascularized bone graft should be reserved for patients with alloplastic material failure. This rationale can avoid subjecting the patient to an unnecessary extensive mandibular reconstructive procedure.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Chirurgie (generalites). Transplantations, greffes d'organes et de tissus. Pathologie des greffons, Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases, Technologie. Biomatériaux. Equipements, Technology. Biomaterials. Equipments, Génie biomédical, Biomedical engineering, Ingeniería biomédica, Mammalia, Rodentia, Vertebrata, Animal, Biocompatibilité, Biocompatibility, Biocompatibilidad, Chirurgie, Surgery, Cirugía, Ethylène polymère, Polyethylene, Etileno polímero, Inflammation, Inflamación, Matériau implanté, Implanted material, Material implantado, Propriété matériau, Properties of materials, Propiedad material, Rat, Rata, Structure surface, Surface structure, Estructura superficie, Vinylique alcool polymère, Polyvinylalcohol, and Vinílico alcohol polímero

The purpose of this study was to examine the relationship between tissue response and the membrane surface structure. A series of ethylene vinyl alcohol (EVAL) membranes provide an ideal system for a study of the relative contributions to biocompatibility derived from the surface morphology. This is different from other reports using different kinds of polymers, which may thus result in considerable variation since polymer implants are both chemically and physically heterogeneous. This study demonstrated that the tissue response to three different membrane structures were quite different. Flat and dense EVAL surfaces induced a mild foreign body reaction indicating that EVAL copolymer does not provide a stimulus for a continued inflammatory response. The inflammatory response was strong using a porous surface and a surface with a particulate morphology. In addition, particulate surfaces provoked a more intense inflammatory response than porous surfaces, indicating that a material in particulate form, suitable for phagocytosis, may provoke a different degree of inflammatory response than the same material in a nonphagocytosable form. Therefore, although a material may be considered to be biocompatible, however, its surface properties may alter the observed tissue reaction and inflammatory response. Consequently, the surface properties should be suitably selected according to the purpose for which the material is to be used.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Radiotherapie. Traitement instrumental. Physiotherapie. Reeducation. Readaptation, orthophonie, crenotherapie. Traitement dietetique et traitements divers (generalites), Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects), Technologie. Biomatériaux. Equipements. Matériel. Appareillage, Technology. Biomaterials. Equipments. Material. Instrumentation, Génie biomédical, Biomedical engineering, Ingeniería biomédica, Essai déchirement, Tearing test, Ensayo desgarramiento, Matériau renforcé, Reinforced material, Material reforzado, Procédé sol gel, Sol gel process, Procedimiento sol gel, Propriété matériau, Properties of materials, Propiedad material, Propriété mécanique, Mechanical properties, Propiedad mecánica, Précipitation, Precipitation, Precipitación, Silice, Silica, Sílice, Siloxane(diméthyl) polymère, Dimethylsiloxane polymer, Siloxano(dimetil) polímero, Thermogravimétrie, Thermogravimetry, and Termogravimetría

Tetraethoxysilane was used to end-link functionally-terminated poly(dimethyl-siloxane) chains, and then to serve as the source of reinforcing silica particles upon its hydrolysis and condensation within the elastomeric networks. These in-situ filled elastomers were characterized using transmission electron microscopy, thermogravimetric analysis, and tearing energy measurements. The electron micrographs showed the presence of well-dispersed, unagglomerated silica particles with average diameters rather narrowly distributed over the range 150-250 A. These reinforcing particles were found to improve the thermal properties of the networks. Specifically, the larger the amount of filler thus incorporated, the higher the onset degradation temperature, and the larger the weight residue at 800°C. Effects were also found with regard to the tearing measurements, with the filled materials showing unstable tearing (stick-slip tearing), particularly at higher tearing rates. In contrast, the unfilled materials showed steady tearing. The tearing energies of the filled materials were significantly larger than those of the unfilled material. A marked increase in the tear strength occurred upon increasing the silica content up to 10 wt.%, followed by smaller improvements with additional increases in silica content.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Radiotherapie. Traitement instrumental. Physiotherapie. Reeducation. Readaptation, orthophonie, crenotherapie. Traitement dietetique et traitements divers (generalites), Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects), Technologie. Biomatériaux. Equipements. Matériel. Appareillage, Technology. Biomaterials. Equipments. Material. Instrumentation, Génie biomédical, Biomedical engineering, Ingeniería biomédica, Biodégradabilité, Biodegradability, Biodegradabilidad, Caprolactone polymère, Polycaprolactone, Caprolactona polímero, Depsipeptide, Depsipéptido, Glycolique acide polymère, Glycolic acid polymer, Glicólico ácido polímero, Hydrogel, Hidrogel, Microsphère, Microsphere, Microsfera, Polymérisation photochimique, Photopolymerization, Polimerización fotoquímica, Propriété physicochimique, Physicochemical properties, Propiedad fisicoquímica, Rayonnement UV, Ultraviolet radiation, Radiación ultravioleta, Synthèse chimique, Chemical synthesis, Síntesis química, Sérine, Serine, and Serina

Polydepsipeptide networks and cross-linked beads have been prepared by UV photopolymerization of acrylated poly(ε-caprolactone-co-glycolic acid-co-L-serine) [PCL (Glc-Ser)]. The acrylated PCL(Glc-Ser) cross-linked polymer networks obtained were glassy and transparent, and the gel content was approximately 85%. The network showed relatively low swelling in water but is easily swelled in chloroform and in dimethyl sulfoxide. The acrylate polymers on copolymerization with 2-hydroxyethyl methacrylate (HEMA) resulted in cross-linked networks [PCL(Glc-Ser)/HEMA], which were swelling in water and in DMSO showing the potential of the polymer in hydrogel applications. The modified PCL(Glc-Ser) beads prepared by UV initiated suspension polymerization and were characterized by optical microscopy. These degradable networks and beads may be useful as polymer scaffolds for biomaterial applications.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Chirurgie (generalites). Transplantations, greffes d'organes et de tissus. Pathologie des greffons, Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases, Technologie. Biomatériaux. Equipements, Technology. Biomaterials. Equipments, Génie biomédical, Biomedical engineering, Ingeniería biomédica, Amidon, Starch, Almidón, Calcium carbonate, Calcio carbonato, Consolidation, Consolidación, Céramique, Ceramic materials, Cerámica, Matériau bioactif, Bioactive material, Material bioactivo, Matériau implanté, Implanted material, Material implantado, Matériau poreux, Porous material, Material poroso, Microstructure, Microestructura, Procédé fabrication, Manufacturing process, and Procedimiento fabricación

Macroporous calcium carbonate (CaCO3) materials with porous structures suitable for implantation purposes were prepared in the present work, A new direct consolidation technique that uses starch granules as consolidator agent and as pore formers, combined with other larger organic inclusions, enabled us to tailor the porous microstructure for the intended application. Pore sizes as large as several hundreds of micrometers could be generated without matrix cracking, due to the high solid loading of the starting suspensions. The macroporous CaCO3 bodies fabricated exhibit an accentuated bioactivity even for short soaking time periods. The crystalline calcium phosphate phases precipitate preferentially in the pores, pore boundaries, or in other strained sites at the surface of the samples.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Biotechnologie, Biotechnology, Méthodes. Procédés. Technologies, Methods. Procedures. Technologies, Techniques d'immobilisation, Immobilization techniques, Immobilisation d'enzymes et autres molécules, Immobilization of enzymes and other molecules, Enzyme, Enzima, Génie biomédical, Biomedical engineering, Ingeniería biomédica, Hydrolases, Peptidases, Serine endopeptidases, Acrylamide dérivé polymère, Acrylamide derivative polymer, Acrilamida derivado polímero, Catalyseur, Catalyst, Catalizador, Chymotrypsin, Composé hydrophobe, Hydrophobic compound, Compuesto hidrofobo, Enzyme immobilisée, Immobilized enzyme, Enzima inmovilizada, Gel, Freeze, Helada, Mécanisme réaction, Reaction mechanism, Mecanismo reacción, Sensibilité thermique, Thermal sensibility, Sensibilidad térmica, Synthèse peptidique, Peptide synthesis, and Síntesis peptídica

The peptide syntheses were performed with α-chymotrypsin immobilized in the thermosensitive poly(N-isopropylacrylamide/acrylamide) (NIPAAm/AAm) gels. In the reaction between N-acetylphenylalanine ethyl ester (Ac-Phe-OEt) and alaninamide (Ala-NH2), the product ratio of Ac-Phe-Ala-NH2/Ac-Phe-OH increased with lowering temperature. The highest ratio was 3.3 in the reaction with immobilized enzyme at -10°C, while that was around 1.4 with free enzyme at 34°C. On the contrary, CBZ-Phe-Leu-NH2 obtained from N-carbobenzoxyphenylalanine (CBZ-Phe) and leucinamide (Leu-NH2) increased with increasing temperature (conversion: 13% at 10°C, 34% at 35°C) in Tris buffer without the organic solvent. The gel of NIPAAm copolymerized with AAm (NIPAAm/AAm = 80/20) was effective as compared with the poly(NIPAAm) gel for the peptide production catalyzed by α-chymotrypsin using the ester substrate as the acyl donor. The reaction mechanism was discussed in connection with the hydrophobic surroundings inside the deswollen thermosensitive polymer gel.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Vertebres: systeme osteoarticulaire, muscle strie, Vertebrates: osteoarticular system, musculoskeletal system, Squelette et articulations, Skeleton and joints, Artiodactyla, Mammalia, Ungulata, Vertebrata, Animal, Biomécanique, Biomechanics, Biomecánica, Bovin, Bovine, Bovino, Essai charge, Loading test(mechanics), Ensayo carga, Essai cisaillement, Shear test, Ensayo cortante, Essai propagation fissure, Fracture toughness test, Prueba propagación fisuras, Essai traction, Tension test, Ensayo tracción, In vitro, Orientation, Orientación, Os cortical, Cortical bone, Hueso cortical, Système ostéoarticulaire, Osteoarticular system, and Sistema osteoarticular

The fracture toughness at crack initiation were determined for bovine cortical bone under tension (mode I), shear (mode II), and tear (mode III). A total of 140 compact tension specimens, compact shear specimens and triple pantleg (TP) specimens were used to measure fracture toughness under tension, shear, and tear, respectively. Multiple-sample compliance method was utilized to measure the critical strain energy release rate (Gc) at the a/W = 0.55 (crack length, a, to specimen width, W, ratio). The critical stress intensity factor (Kc) was also calculates from the critical loading (Pc) of the specimens at the a/W=0.55, The effect of the anisotropy of bone on its resistance to crack initiation under shear and tear loading was investigated as well. Fracture toughness of bone with precrack orientations parallel (designed as longitudinal fracture) and vertical (designed as transverse fracture) to the longitudinal axis of bone were compared. In longitudinal fracture, the critical strain energy release rate (Gc) of cortical bone under tension, shear, and tear was 644 ± 102, 2430 ± 836, and 1723 ± 486 N/m, respectively. In transverse fracture, the critical strain energy release rate (Gc) of cortical bone under tension, shear, and tear was 1374 ± 183, 4710 ± 1284, and 4016 ± 948 N/m, respectively. An unpaired t-test analysis demonstrated that the crack initiation fracture toughness of bone under shear and tear loading were significantly greater than that under tensile loading in both longitudinal and transverse fracture (P < 0.0001 for all). Our results also suggest that cortical bone has been designed to prevent crack initiation in transverse fracture under tension, shear, and tear.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Radiotherapie. Traitement instrumental. Physiotherapie. Reeducation. Readaptation, orthophonie, crenotherapie. Traitement dietetique et traitements divers (generalites), Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects), Technologie. Biomatériaux. Equipements. Matériel. Appareillage, Technology. Biomaterials. Equipments. Material. Instrumentation, Génie biomédical, Biomedical engineering, Ingeniería biomédica, Absorption, Absorción, Biodégradabilité, Biodegradability, Biodegradabilidad, Cellulose(hydroxypropyl), Celulosa(hidroxipropil), Cellulose(hydroxyéthyl), Cellulose(hydroxyethyl), Celulosa(hidroxietil), Copolymère greffé, Graft copolymer, Copolímero injertado, Copolymérisation ouverture cycle, Ring opening copolymerization, Copolimerización abertura ciclo, Lactique acide copolymère, Lactic acid copolymer, Láctico ácido copolímero, Propriété matériau, Properties of materials, Propiedad material, Proton, Protón, Spectrométrie RMN, NMR spectrometry, Espectrometría RMN, Synthèse chimique, Chemical synthesis, Síntesis química, Toxicité, Toxicity, and Toxicidad

This paper reported the grafting copolymerization of L-lactide onto hydroxyethyl cellulose (PLA-HEC) or hydroxypropyl cellulose (PLA-HPC). They were obtained from ring-opening copolymerization of L-lactide with HEC or HPC in different mole ratios at 128°C. Sn(Oct)2 or LiCl was used as catalysts for the polymerization reaction. 400 MHz 1H NMR analysis of products indicated that both Sn(Oct)2 and LiCl could catalyze the reactions. Both PLA-HEC and PLA-HPC were biodegradable polymers with a good bioabsorbability, lack of toxicity, and were suitable for the use as tissue engineering materials.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Biologie moleculaire et cellulaire, Molecular and cellular biology, Physiologie cellulaire, Cell physiology, Effets d'agents physiques et chimiques, Effects of physical and chemical agents, Analyse structurale, Structural analysis, Análisis estructural, Apoptose, Apoptosis, Basse énergie, Low energy, Baja energía, Blé, Wheat, Trigo, Culture cellulaire, Cell culture, Cultivo celular, Hydrogène, Hydrogen, Hidrógeno, Implantation ion, Ion implantation, Implantación ión, Modélisation, Modeling, Modelización, Morphologie, Morphology, Morfología, Produit radioactif, Radioactive product, and Producto radioactivo

Embryos of wheat (Triticum aestivum L.) seeds were implanted by 14N+ at the energy of 30 keV. The fluence ranged from 5 x 1014 to 6 X 1016 cm-2. Scanning electron microscopy (SEM) and optical microscopy (OM) were used to study the structural evolution of the irradiated embryonic cells. With the increase of fluence, the cells in the several layers near the surface of the embryos suffered gradually intensified damage. A schematic model was proposed to illustrate the progressive morphological development of the cells during ion irradiation with the increase of fluence. Cell death was observed in the embryos of the seeds cultivated for 12 h or more, which may attribute to the death of the seeds.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Traumatismes. Maladies dues aux agents physiques, Traumas. Diseases due to physical agents, Traumatismes des membres. Traumatismes du rachis, Injuries of the limb. Injuries of the spine, Système ostéoarticulaire pathologie, Diseases of the osteoarticular system, Sistema osteoarticular patología, Traumatisme, Trauma, Traumatismo, Cal, Callus, Callo, Cicatrisation, Cicatrization, Cicatrización, Collagène, Collagen, Colágeno, Fibrille, Fibril, Fibrilla, Fracture, Fractura, Homme, Human, Hombre, Microstructure, Microestructura, Mécanisme action, Mechanism of action, Mecanismo acción, Os long, Long bone, Hueso largo, Os, Bone, Hueso, Réparation, Repair, and Reparación

Accurate knowledge of bone fracture healing process is of clinical and theoretical importance in bone repair and regeneration, and biomineralization. It is well known that the histological healing occurs via the formation of hematoma, fibrocartilage, bony callus and bone modeling/remodeling. However, the detailed process from fracture to healing at the microstructural level remains unclear. In the present study, an evolutionary model of external callus is proposed, in which five representative stages are presented in terms of the organization of collagen and minerals during the formation of bony callus. The first stage is the formation of loose, disordered collagen fibrils, which is followed by mineralization on some of these individual microfibrils. Then the matrix is characterized by the fusion of mineralized individual fibrils into bundles. In the third stage, the absorption of disordered matrix occurs. This is gradually replaced by ordered collagen in stage four. Finally, completely ordered mineralized tissue is formed. The proper sequence of the process plays an important role in deciding the success of healing. In addition to the common mineral phase of hydroxyapatite (HA), dicalcium phosphate dihydrate (DCPD) phase was also found in early stage of healing, especially in rapid healing (children's callus). It vanished in the following process of healing. The deposition of DCPD is supposed to be brought about by some non-collagenous protein.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Radiotherapie. Traitement instrumental. Physiotherapie. Reeducation. Readaptation, orthophonie, crenotherapie. Traitement dietetique et traitements divers (generalites), Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects), Technologie. Biomatériaux. Equipements. Matériel. Appareillage, Technology. Biomaterials. Equipments. Material. Instrumentation, Génie biomédical, Biomedical engineering, Ingeniería biomédica, Analyse structurale, Structural analysis, Análisis estructural, Anisotropie, Anisotropy, Anisotropía, Article synthèse, Review, Artículo síntesis, Composition chimique, Chemical composition, Composición química, Milieu synthétique, Synthetic medium, Medio sintético, Minéralisation, Mineralization, Mineralización, Propriété mécanique, Mechanical properties, Propiedad mecánica, Technologie matériau, Material engineering, Tecnología material, and Matériau but multiple

The materials formed by organisms are often the products of hundreds of millions of years of fine-tuning by evolution. They thus incorporate some neat solutions to complex structural problems. Here, we examine four different mineralized biological materials that all appear to fulfill a multipurpose function. They are the crossed lamellar structure of mollusk shells, the skeleton of sea urchins, the lamellar bone type of vertebrates, and the biogenic silica deposited by a wide variety of organisms. They all have very different structures and compositions, but are all structurally designed to reduce the extent of mechanical anisotropy. The strategies for reducing anisotropy are manifold, including features that to date have not been incorporated into synthetic materials.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Biotechnologie, Biotechnology, Méthodes. Procédés. Technologies, Methods. Procedures. Technologies, Méthodes et appareillages divers, Various methods and equipments, Biodétecteurs. Biocapteurs, Biosensors, Enzyme, Enzima, Génie biomédical, Biomedical engineering, Ingeniería biomédica, Oxidoreductases, Biodétecteur, Biosensor, Biodetector, Chimiluminescence, Chemiluminescence, Quimioluminiscencia, Enzyme immobilisée, Immobilized enzyme, Enzima inmovilizada, Etat natif, Native state, Estado nativo, Etude comparative, Comparative study, Estudio comparativo, Glucose oxidase, Procédé sol gel, Sol gel process, and Procedimiento sol gel

In this paper, glucose oxidase (GOD) was immobilized in the course of sol-gel process of TEOS, and we cast the GOD-doped sol to different supports (silica gel and molecular sieve) to prepare the GOD columns. It was demonstrated that the activity of GOD remained high in sol-gel matrix. With the application of the GOD column prepared with sol-gel method to a flowing injection chemiluminescent system, glucose could be effectively determined with the linear range of the concentration in 3.5-70 μmol/l and the detection limit was at 0.6 μ mol/l.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Chirurgie (generalites). Transplantations, greffes d'organes et de tissus. Pathologie des greffons, Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases, Chirurgie cardiaque, Surgery of the heart, Appareil circulatoire pathologie, Cardiovascular disease, Aparato circulatorio patología, Artiodactyla, Cardiopathie, Heart disease, Cardiopatía, Mammalia, Myocarde pathologie, Myocardial disease, Miocardio patología, Succédané sang, Blood substitute, Substituto sangre, Ungulata, Vertebrata, Animal, Calcification, Calcificación, Chirurgie, Surgery, Cirugía, Collagène, Collagen, Colágeno, Glutaral, In vivo, Matériau implanté, Implanted material, Material implantado, Porc, Pig, Cerdo, Prévention, Prevention, Prevención, Rayonnement UV, Ultraviolet radiation, Radiación ultravioleta, Réticulation, Crosslinking, Reticulación, Valvule cardiaque, Heart valve, and Válvula cardíaca

Porcine aortic valve, of which tissue structural collagen matrix is cross-linked by glutaraldehyde (GA) to enhance mechanical property, is widely used in clinics, but gradual calcification occurs after implantation. Cross-linking the valve by 24 h of ultraviolet (UV) ray irradiation that induces collagen fibrous cross-link resulted in less calcium deposition than GA-pretreated leaflets. After 3 days, calcium level in GA-treated leaflets was distinctively higher than in leaflets cross-linked by UV irradiation for 24 h and in the non-treated control leaflets. The exposure time of UV irradiation was not significantly correlated with the extent of calcification. In all the test groups, molar [Ca]/[P] ratio gradually decreased as time went by, and UV-irradiated and control leaflets demonstrated molar [Ca]/[P] ratio close to apatite as the predominant mineral phase and GA-treated leaflet reached the similar molar ratio after 30 days. In animal experiment, the leaflet treated by UV irradiation demonstrated a stable surface without calcification after 2 months of implantation.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Radiotherapie. Traitement instrumental. Physiotherapie. Reeducation. Readaptation, orthophonie, crenotherapie. Traitement dietetique et traitements divers (generalites), Radiotherapy. Instrumental treatment. Physiotherapy. Reeducation. Rehabilitation, orthophony, crenotherapy. Diet therapy and various other treatments (general aspects), Technologie. Biomatériaux. Equipements. Matériel. Appareillage, Technology. Biomaterials. Equipments. Material. Instrumentation, Génie biomédical, Biomedical engineering, Ingeniería biomédica, Collagène, Collagen, Colágeno, Diffusivité, Diffusivity, Difusibilidad, Effet soluté, Solute effect, Efecto disolución, Etude comparative, Comparative study, Estudio comparativo, Gel, Freeze, Helada, In vitro, Microstructure, Microestructura, Milieu culture, Culture medium, Medio cultivo, Procédé fabrication, Manufacturing process, Procedimiento fabricación, Réticulation, Crosslinking, Reticulación, Teneur eau, Water content, and Dosis agua

Collagen gel was prepared by an ordinary method as that used for preparing a cell-culture medium from an aqueous type-1 atelocollagen solution through crosslinking with glutaraldehyde (GA). Solute diffusivity in the gels prepared in the different conditions was discussed, being related to their water content. The water content of the gel decreased with increasing GA concentration at crosslinking but the solute diffusivity in the gel hardly changed. On the other hand, collagen concentration, at crosslinking of the collagen solution, dramatically affected the solute diffusivity of the obtained gel, although the water content of the gel was not changed and maintained at higher value around 0.9. The inconsistency suggested that the gel had a heterogeneous microstructure although the content of the gel was almost water. This result suggests that the process to prepare collagen medium for cell culture affects cell growth in the case that mass transfer is dominant.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences biologiques fondamentales et appliquees. Psychologie, Fundamental and applied biological sciences. Psychology, Biotechnologie, Biotechnology, Méthodes. Procédés. Technologies, Methods. Procedures. Technologies, Techniques d'immobilisation, Immobilization techniques, Immobilisation de cellules entières et d'organites cellulaires, Immobilization of organelles and whole cells, Génie biomédical, Biomedical engineering, Ingeniería biomédica, Alginate, Alginates, Alginato, Cellule immobilisée, Immobilized cell, Célula inmovilizada, Lysine polymère, Lysine polymer, Lisina polímero, Microencapsulation, Microencapsulación, Méthode photochimique, Photochemical method, Método fotoquímico, Photosensibilité, Photosensitivity, Fotosensibilidad, Polycation, Policatión, Propriété matériau, Properties of materials, Propiedad material, Propriété mécanique, Mechanical properties, Propiedad mecánica, Réticulation, Crosslinking, and Reticulación

Microencapsulation is one of the most important techniques used in immobilizing cells for biomedical applications. Of the many microcapsules derived from various materials, the one formed by alginate and poly(L-lysine) is probably the most common. These microcapsules, prepared under mild conditions, provide an adequate environment for cell growth. Unfortunately, they usually lack mechanical strength due to the ionic interaction, instead of covalent bonding, between alginate and polycations. In order to improve the mechanical strength, we have investigated the feasibility of using poly(vinylamine) and poly(allylamine) to replace the conventional poly(L-lysine). Of these two polycations, poly(allylamine) formed microcapsules of about the same strength as that prepared from poly(L-lysine). On the other hand, microcapsules prepared from alginate and poly(vinylamine) have about 40% of capsules weaker than that prepared from poly(L-lysine). However, the remaining 60% of its population remained intact even after 48 h of mechanical vibration test. An alternative strengthening method is to cross-link poly(L-lysine) by chemical or photochemical process. The chemical method was conducted by treating microcapsules with tosylated poly(vinylalcohol). This treatment resulted in the cross-linking of poly(L-lysine) in the capsular membrane and therefore, a significant improvement of capsular strength. For the photochemical method, a photosensitive polycation was prepared by partially modifying the amino groups of the poly(L-lysine) with α-phenylcinnamyldieneneacetyl chloride. The capsules formed from alginate and this photosensitive polymer yield the highest mechanical strength after irradiation of light at ∼ 320 nm. All microcapsules investigated were permeable to the proteins of mid-size molecular weight such as myoglobin. Cells can be entrapped and cultured by using this encapsulation technology.

Biochemistry, molecular biology, biophysics, Biochimie, biologie moléculaire, biophysique, General chemistry, physical chemistry, Chimie générale, chimie physique, Polymers, paint and wood industries, Polymères, industries des peintures et bois, Sciences biologiques et medicales, Biological and medical sciences, Sciences medicales, Medical sciences, Chirurgie (generalites). Transplantations, greffes d'organes et de tissus. Pathologie des greffons, Surgery (general aspects). Transplantations, organ and tissue grafts. Graft diseases, Chirurgie orl et maxillofaciale. Chirurgie dentaire. Orthodontie, Head and neck surgery. Maxillofacial surgery. Dental surgery. Orthodontics, Chirurgie des voies aérodigestives supérieures, Surgery of the upper aerodigestive tract, Greffe, Graft, Injerto, Amélioration, Improvement, Mejoría, Autogreffe, Autograft, Autoinjerto, Cavité buccale, Oral cavity, Cavidad bucal, Chirurgie, Surgery, Cirugía, Cicatrisation, Cicatrization, Cicatrización, Culture tissu, Tissue culture, Cultivo tejido, Efficacité, Efficiency, Eficacia, Epithélium, Epithelium, Epitelio, Homme, Human, Hombre, Palais, Palate, and Paladar

Cultured allografts derived from mucosal tissue provide a potent stimulus to wound healing in a wide variety of wounds. In the field of oral surgery, mucoperiosteal defect of the hard palate after palatoplasty causes scar contraction, leading to poor growth of the maxilla. The promotion of wound healing in these cases through cultured epithelial allografting has been reported. Cultured epithelial allografting was done using a stranger's cultured cells. We grafted cultured oral epithelium in the hope of improving growth of maxilla. Clefts of the soft and hard palate (seven patients), and a cleft of the soft palate (two patients) were present. Average patient age was 1 year 4 months. Palatoplasty was done by a conventional pushback operation. Oral epithelial cells in healthy adults were cultured using 3T3 cells as the feeder layer. After 3 weeks, cultured oral mucosal epithelium was grafted on a raw surface following palatoplasty. In all patients, the grafted areas underwent re-epithelialization after about 1 week and did not exhibit any side effects of graft rejection. Grafted areas healed completely after 2-3 weeks in all cases. Cultured epithelial allografts serve as a temporary biological dressing, and accelerates epithelialization and wound healing. Allografting by cultured oral epithelium has proved to be a very useful therapeutic modality in palatoplasty, as well as effective augmentation materials in cases of oral mucosal defects.