104 research outputs found
Tailoring hierarchical meso- macroporous 3D scaffolds: from nano to macro
Bone tissue regeneration requires the use of 3D scaffolds which mimic the architecture of the natural extracellular matrix, creating an adequate microenvironment for bone cell growth. Such 3D scaffolds need surface properties suitable for biological recognition in the early stage of cell adhesion, necessary to ensure complete cell colonization, retained cell functionality, and subsequently bone regeneration. Herein, hierarchical 3D scaffolds based on new hydroxyapatite/mesoporous glass nanocomposite bioceramic (MGHA) exhibiting different scales of porosity have been synthesized. These 3D scaffolds possess: (i) highly ordered mesopores with diameters of 10 nm; (ii) macropores with diameters in the 30-80 mu m range with interconnections of 1-10 mu m; and (iii) large macropores of ca. 500 mu m. To improve their surface properties, 3D scaffolds were modified through direct functionalization with amine propyl groups, which notably improve preosteoblast adhesion, proliferation (2.3 fold), differentiation (4.8 fold) and further cell colonization of these scaffolds. The observed enhancement can be related to these amine groups which favour early adhesion, e. g., based on nonspecific protein adsorption as was demonstrated by ellipsometry. These results suggest that the combination of hierarchical structure design and amine surface modification of hydroxyapatite/mesoporous nanocomposite scaffolds yields a double increase in cell proliferation, as well as a quadruple increase in cell differentiation, demonstrating the potential of these nanocomposite materials for bone tissue regeneration purposes
Razvoj i validacija spektrofotometrijskih metoda za odreÄivanje ceftazidima u farmaceutskim doziranim pripravcima
Two spectrophotometric methods for the determination of ceftazidime (CFZM) in either pure form or in its pharmaceutical formulations are described. The first method is based on the reaction of 3-methylbenzothiazolin-2-one hydrazone (MBTH) with ceftazidime in the presence of ferric chloride in acidic medium. The resulting blue complex absorbs at λmax 628 nm. The second method describes the reaction between the diazotized drug and N-(1-naphthyl)ethylenediamine dihydrochloride (NEDA) to yield a purple colored product with λmax at 567 nm. The reaction conditions were optimized to obtain maximum color intensity. The absorbance was found to increase linearly with increasing the concentration of CFZM; the systems obeyed the Beerâs law in the range 210 and 1050 ”g mL1 for MBTH and NEDA methods, respectively. LOD, LOQ and correlation coefficient values were 0.15, 0.79 and 0.50, 2.61. No interference was observed from common excipients present in pharmaceutical formulations. The proposed methods are simple, sensitive, accurate and suitable for quality control applications.Razvijene su dvije spektrofotometrijske metode za odreÄivanje ceftazidima (CFZM), Äistog ili u farmaceutskim pripravcima. Prva metoda se temelji na reakciji 3-metilbenzotiazolin-2-on hidrazona (MBTH) sa ceftazidimom u prisutnosti ĆŸeljezovog(III) klorida u kiselom mediju. Nastaje plavi kompleks s maksimumom apsorpcije pri λmax 628 nm. Druga metoda se temelji na reakciji izmeÄu diazotiranog lijeka i N-(1-naftil)etilendiamin dihidroklorida (NEDA), pri Äemu nastaje ljubiÄasti produkt s λmax pri 567 nm. Reakcijski uvjeti su optimirani da se dobije maksimalni intenzitet boje. Apsorbancija raste linearno s poraĆĄÄu koncentracije CFZM; sustavi slijede Beerov zakon u koncentracijskom podruÄju 210 za MBTH metodu i 1050 ”g mL1 za NEDA metodu. LOD i LOQ te vrijednosti korelacijskog koeficijenta su 0,15, 0,79 i 0,50, 2,61. UobiÄajene pomoÄne tvari ne smetaju odreÄivanju ceftazidima. PredloĆŸene metode su jednostavne, osjetljive, toÄne i pogodne za primjenu u kontroli kvalitete
Revista de Vertebrados de la Estación Biológica de Doñaña
AlimentaciĂłn de la boga del Guadiana (Chondrostoma polylepis wi/lkommi, Stein. 1866) en la interfase rĂo-embalse de Sierra Boyera (CĂłrdoba. España)PredaciĂłn del bĂșho real (Bubo bubo) sobre la perdiz roja (Alectoris rufa): selecciĂłn de edad y sexoAlimentaciĂłn de la nutria (Lutra lufra L, 1758)en el Nordeste de la PenĂnsula IbĂ©ricaDatos sobre la distribuciĂłn espacialde micromamĂferos en el Parque Nacionalde DoñanaGuĂa para el reconocimiento microscĂłpico de los pelos de los mamĂferos de la Patagonia.Sobre la distribuciĂłn geogrĂĄfica de Anaecypris hispanica (STEINDACHNER, 1866) (OSTEICHTHYES, CYPRINIDAE)CronologĂa del periodo reproductor de Rana temporaria L. en La Coruña (NW de España).Un nuevo caso de melanismo en Natrix natrix (LINNAEUS 1758) procedente de Fuente DĂ© (Santander)Nuevas citas de anfibios y reptiles para el SE de la PenĂnsula IbĂ©rica.Datos sobre la dieta invernal del BĂșho chico (Asia atus) en la provinvia de LeĂłnLa DistribuciĂłndel Mara (Dolichotis patagonum) segĂșn criterios ecolĂłgicos e histĂłricosSolapamiento entre la dieta de la cabra montĂ©s (Capra pyrenaica) y la del muflĂłn (Ovis musimon)Nota sobre dietas de carnĂvoros e Ăndices de abundancia en una Reserva de caza del norte de España.DiscriminaciĂłn osteomĂ©trica en el gĂ©neroTalpa (LINNEO, 1758), en el norte IbĂ©ricoObservaciones sobre el comportamiento depredativo de algunos colĂșbridos IbĂ©ricos en estado salvajePeer reviewe
Permanent Genetic Resources added to Molecular Ecology Resources Database 1 October 2010-30 November 2010
This article documents the addition of 277 microsatellite marker loci to the Molecular Ecology Resources Database. Loci were developed for the following species: Ascochyta rabiei, Cambarellus chapalanus, Chionodraco hamatus, Coptis omeiensis, Cynoscion nebulosus, Daphnia magna, Gerbillus nigeriae, Isurus oxyrinchus, Lates calcarifer, Metacarcinus magister, Oplegnathus fasciatus, Pachycondyla verenae, Phaethon lepturus, Pimelodus grosskopfii, Rotylenchulus reniformis, Scomberomorus niphonius, Sepia esculenta, Terapon jarbua, Teratosphaeria cryptica and Thunnus obesus. These loci were cross-tested on the following species: Austropotamobius italicus, Cambarellus montezumae, Cambarellus puer, Cambarellus shufeldtii, Cambarellus texanus, Chionodraco myersi, Chionodraco rastrospinosus, Coptis chinensis, Coptis chinensis var. brevisepala, Coptis deltoidea, Coptis teeta, Orconectes virilis, Pacifastacus leniusculus, Pimelodus bochii, Procambarus clarkii, Pseudopimelodus bufonius, Rhamdia quelen, Sepia andreana, Sepiella maindroni, Thunnus alalunga, Thunnus albacares, Thunnus maccoyii, Thunnus orientalis, Thunnus thynnus and Thunnus tonggol
Interaction of Mesoporous Silica Nanoparticles with Human Red Blood Cell Membranes: Size and Surface Effects
The interactions of mesoporous silica nanoparticles (MSNs) of different particle sizes and surface properties with human red blood cell (RBC) membranes were investigated by membrane filtration, flow cytometry, and various microscopic techniques. Small MCM-41-type MSNs (âŒ100 nm) were found to adsorb to the surface of RBCs without disturbing the membrane or morphology. In contrast, adsorption of large SBA-15-type MSNs (âŒ600 nm) to RBCs induced a strong local membrane deformation leading to spiculation of RBCs, internalization of the particles, and eventual hemolysis. In addition, the relationship between the degree of MSN surface functionalization and the degree of its interaction with RBC, as well as the effect of RBCâMSN interaction on cellular deformability, were investigated. The results presented here provide a better understanding of the mechanisms of RBCâMSN interaction and the hemolytic activity of MSNs and will assist in the rational design of hemocompatible MSNs for intravenous drug delivery and in vivo imaging
Silica Materials for Medical Applications
The two main applications of silica-based materials in medicine and biotechnology, i.e. for bone-repairing devices and for drug delivery systems, are presented and discussed. The influence of the structure and chemical composition in the final characteristics and properties of every silica-based material is also shown as a function of the both applications presented. The adequate combination of the synthesis techniques, template systems and additives leads to the development of materials that merge the bioactive behavior with the drug carrier ability. These systems could be excellent candidates as materials for the development of devices for tissue engineering
Interaction of Mesoporous Silica Nanoparticles with Human Red Blood Cell Membranes: Size and Surface Effects
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