ABSTRACT
In this study a phosphate-free glass-ceramic porous scaffold was synthesized by a three-step methodology involving slurry preparation, induction of porosity by surfactant-assisted foaming following by freeze-drying and sintering. This inorganic scaffold was characterized by X-ray diffraction, scanning electron microscope (SEM), degradation and bioactivity. Thermal treatment at 750 °C showed two new crystalline phases, combeite and nepheline, into the glassy matrix responsible for its properties. The cell response of the scaffold was also evaluated for using as a bone graft substitute. A commercial Biphasic Calcium Phosphate, BCP, scaffold was assessed in parallel as reference material. Microstructures obtained by SEM showed the presence of macro, meso and microporosity. The glass-ceramic scaffold possesses an interconnected porosity around 31% with a crack-pore system that promote the protein adsorption and cell attachment. Glass-ceramic scaffold with high concentration of calcium ions shows an antimicrobial behavior against Escherichia coli after 24 h of contact. Nepheline phase present in the glass-ceramic structure is responsible for its high mechanical properties being around 87 MPa. Glass-ceramic scaffold promotes greater protein adsorption and therefore the attachment, spreading and osteodifferentiation of Adipose Derived Stem Cells than BCP scaffold. A higher calcification was induced by glass-ceramic scaffold compared to reference BCP material.
Subject(s)
Bone Substitutes/chemistry , Ceramics/pharmacology , Escherichia coli/drug effects , Mesenchymal Stem Cells/cytology , Tissue Scaffolds/chemistry , Bone Regeneration , Calcium/chemistry , Cell Adhesion , Cell Proliferation , Cells, Cultured , Ceramics/chemistry , Escherichia coli/growth & development , Freezing , Hot Temperature , Humans , Materials Testing , Microscopy, Electron, Scanning , Porosity , Tissue Engineering/methods , Tissue Scaffolds/microbiology , X-Ray DiffractionABSTRACT
OBJECTIVES: To compare biofilm formation on the surface of different ceramic biomaterials to be used in implant dentistry. METHODS: In vitro biofilm formation was investigated from mixtures of standard reference strains of Streptococcus oralis, Veillonella parvula, Actinomyces naeslundii, Fusobacterium nucleatum, Aggregatibacter actinomycetemcomitans and Porphyromonas gingivalis. Sterile ceramic calcium hydroxyapatite discs (HA) as control, sterile Al2O3/Ce-TZP nanocomposite sandblasted discs (material A1) and sterile Al2O3/Ce-TZP nanocomposite sandblasted discs and coated with two types of antimicrobial glasses (materials A2 and A3) were used. Biofilms were grown on the four surfaces and evaluated after 12, 24, 48 and 72 h of incubation. Biofilms were examined by confocal laser scanning microscopy (CLSM). In addition, counts of live bacterial cells of the target species A. actinomycetemcomitans, F. nucleatum and P. gingivalis were calculated by quantitative polymerase chain reaction (qPCR) combined with propidium monoazide (PMA). For data analysis, bacterial counts were compared with a multivariate general lineal model. RESULTS: Using CLSM, cell vitality decreased in A2 and A3. With qPCR-PMA, significant differences in vitality were observed forA. actinomycetemcomitans in A3 after 48 and 72 h of incubation. With respect to the development of the biofilms, a significant increase in counts on HA and materials A1 and A2 was observed for A. actinomycetemcomitans and F. nucleatum. Conversely, for P. gingivalis, no differences were found for HA and materials A1 and A2. SIGNIFICANCE: Differences in biofilm formation were detected among the different tested materials. The ceramic material A3 has an effect on the vitality of A. actinomycetemcomitans growing in an in vitro biofilm model.
Subject(s)
Biocompatible Materials , Fusobacterium nucleatum , Biofilms , Ceramics , Porphyromonas gingivalis , Streptococcus oralisABSTRACT
Human exposure to nanomaterials and nanoparticles is increasing rapidly, but their effects on human health are still largely unknown. Epigenetic modifications are attracting ever more interest as possible underlying molecular mechanisms of gene-environment interactions, highlighting them as potential molecular targets following exposure to nanomaterials and nanoparticles. Interestingly, recent research has identified changes in DNA methylation, histone post-translational modifications, and noncoding RNAs in mammalian cells exposed to nanomaterials and nanoparticles. However, the challenge for the future will be to determine the molecular pathways driving these epigenetic alterations, the possible functional consequences, and the potential effects on health.
Subject(s)
Environmental Exposure/adverse effects , Epigenesis, Genetic/drug effects , Mammals/genetics , Nanoparticles/toxicity , Animals , DNA Methylation/drug effects , DNA Methylation/genetics , Histones/metabolism , Humans , Protein Processing, Post-Translational/drug effectsABSTRACT
Two types of antimicrobial glass fibers containing ZnO and CaO, with diameters ranging from tens of nanometers to 1 µm, were successfully fabricated by a laser spinning technique. The antimicrobial performance was corroborated according to ISO 20743:2013, by using gram-negative (Escherichia coli) and gram-positive (Streptococcus oralis, Streptococcus mutans and Staphylococcus aureus) bacteria, and yeast (Candida krusei) (more than 3 logs of reduction). The metabolic activity and endosomal system of eukaryotic cells were not altered by using eluents of CaO glass submicrometric fibers and ZnO fibers at 1 : 10 dilution as cellular media (viability rates over 70%). A dental material was functionalized by embedding ZnO nanofibers above the percolation threshold (20% wt), creating a three-dimensional (3D) fiber network that added an antimicrobial profile. This new ZnO glass fiber composite is proved non-cytotoxic and preserved the antimicrobial effect after immersion in human saliva. This is the first time that a fiber-reinforced liner with strong antimicrobial-activity has been created to prevent secondary caries. The potential of developing new fiber-reinforced composites (FRCs) with antimicrobial properties opens up an extensive field of dental applications where most important diseases have an infectious origin.
Subject(s)
Anti-Infective Agents/chemistry , Dental Materials/chemistry , Glass/chemistry , Resin Cements/chemistry , Animals , Calcium Compounds/chemistry , Candida , Composite Resins , Dental Stress Analysis , Escherichia coli , Humans , Methacrylates/chemistry , Mice , Microbial Sensitivity Tests , NIH 3T3 Cells , Oxides/chemistry , Saliva/chemistry , Saliva/drug effects , Staphylococcus aureus , Streptococcus mutans , Streptococcus oralis , Zinc/chemistry , Zinc Oxide/chemistryABSTRACT
Introducción: El manejo y administración de hemoderivados es una actividad que realiza el personal de enfermería, por lo cual es de gran importancia tener presente que un uso inadecuado de éstos puede tener consecuencias graves en los pacientes, siendo fundamental el buen desempeño del personal de enfermería para la práctica segura. Objetivo: Evaluar el desempeño de enfermería en el manejo y administración de hemoderivados en un hospital de segundo nivel. Métodos: Estudio de diseño transversal. Se incluyeron enfermeras durante el 1º Enero al 30 junio del 2013. Se utilizó un instrumento validado que consta de 4 criterios con 27 ítems de respuestas dicotómicas para identificar el desempeño en el manejo y ministración de hemoderivados. La población fue dividida por categoría contractual. Análisis estadístico: prueba Chi-cuadrada y/ exacta de Fisher. Resultados: Se incluyeron un total de 110 observaciones a personal de enfermería que administró hemoderivados. Se obtuvo un índice de eficiencia global parcial (IEG) parcial a excelente de 64.5%. No se encontró asociación en el turno (p=0.16), servicio (p=0.31) y/o categoría contractual (p=0.25). Los porcentajes de excelente en el IEF fueron bajos (por turno: matutino y nocturno de 10 y 13 respectivamente, medicina interna y cirugía general 5 y 7%, y conforme a la categoría contractual, la enfermera general obtuvo en excelente sólo el 7.5%). Conclusiones: Nuestros resultados nos alertan para implantar programas de capacitación a enfermeras, para otorgar atención de calidad, disminuyendo los riesgos que comprometan la vida del paciente.
Introduction: Handling and managing blood-derived products is a nursing staff activity and thus, it is very important to keep in mind that an inadequate handling of these products can have serious consequences on patients. Therefore, a safe practice from the nursing staff is fundamental. Objective: To assess the nursing performance related to the handling and management of blood-derived products in a second level hospital. Methods: A transversal study design. Nurses were observed from January 1 to June 30, of 2013. A validated instrument with 27 dichotomy-items, and based on 4 criteria, to assess the handling and management of blood-derived products was used. The population was divided by contractual category. Statistical analysis: Chi square and/or Fisher exact test. Results: A total of 110 observations to the nursing staff handling and managing blood-derived products were included. An index of global efficiency (IGE) of partial to excellent of 64.5% was obtained. No associations were found with shift (p=.16), service (p=.31) and/or contractual category (p=.25). The percentages of excellent in the IEF were low (per shift: morning and night of 10 and 13 respectively; per service: internal medicine and general surgery 5 and 7%, and according to the contractual category, overall excellent nurse obtained only 7.5%). Conclusions: Our results encourage us to foster training programs for nurses in order to enhance the quality of care and also decrease the life risks on the patients.
Subject(s)
Humans , Male , Female , Nursing Staff , Blood Transfusion , MexicoABSTRACT
A biocompatible soda-lime glass-ceramic in the SiO2-Na2O-Al2O3-CaO-B2O3 system containing combeite and nepheline as crystalline phases, has been obtained at 750°C by two different routes: (i) pressureless sintering and (ii) Spark Plasma Sintering. The SPS glass-ceramic showed a bending strength, Weibull modulus, and toughness similar values to the cortical human bone. This material had a fatigue limit slightly superior to cortical bone and at least two times higher than commercial dental glass-ceramics and dentine. The in vitro studies indicate that soda-lime glass-ceramic is fully biocompatible. The in vivo studies in beagle jaws showed that implanted SPS rods presented no inflammatory changes in soft tissues surrounding implants in any of the 10 different cases after four months implantation. The radiological analysis indicates no signs of osseointegration lack around implants. Moreover, the biocide activity of SPS glass-ceramic versus Escherichia coli, was found to be >4log indicating that it prevents implant infections. Because of this, the SPS new glass-ceramic is particularly promising for dental applications (inlay, crowns, etc).
Subject(s)
Calcium Compounds/chemistry , Ceramics/chemistry , Coated Materials, Biocompatible/chemistry , Disinfectants/chemistry , Materials Testing , Mechanical Phenomena , Oxides/chemistry , Sodium Hydroxide/chemistry , Animals , Calcium Compounds/metabolism , Calcium Compounds/pharmacology , Coated Materials, Biocompatible/metabolism , Coated Materials, Biocompatible/pharmacology , Disinfectants/metabolism , Disinfectants/pharmacology , Dogs , Escherichia coli/drug effects , Humans , Minerals/chemistry , Oxides/metabolism , Oxides/pharmacology , Saliva/metabolism , Sodium Hydroxide/metabolism , Sodium Hydroxide/pharmacologyABSTRACT
Objetivo: Medir, mediante el Maslach Burnout Inventory (MBI), los tres aspectos de desgaste profesional que permitan determinar el grado de síndrome del trabajador «quemado» (burnout) que presentan los farmacéuticos comunitarios rurales de España, y correlacionarlo con las características sociodemográficas y de prestación farmacéutica de estos últimos. Metodología: Estudio descriptivo transversal con componentes analíticos realizado mediante encuestas autoadministradas por correo postal dirigidas a una muestra de farmacéuticos titulares de oficinas de farmacia de España de pueblos de hasta 5.000 habitantes. El muestreo tipo aleatorio estratificado se realizó en dos oleadas, entre junio y noviembre de 2009. Se diseñó un cuestionario que contiene tres tipos de variables: sociodemográficas, variables que permiten caracterizar el trabajo del farmacéutico en la oficina de farmacia rural, y los 22 ítems del MBI. La información encuestal se evaluó mediante un análisis descriptivo (frecuencias, medias y desviación estándar), así como con un tratamiento analítico basado en el análisis de la varianza simple y el test de la t de Student. Resultados: Un 9,52% de farmacéuticos padecen el síndrome de burnout, y los valores obtenidos para las tres subescalas, cansancio emocional (CE), despersonalización (DP) y realización personal (RP), muestran unos niveles medios de afectación para las tres, con medias y desviaciones estándar, de 16,4 (DE= 11,7), 5,4 (DE= 5,6) y 36,2 (DE= 9,3), respectivamente. La subescala CE presentó diferencias significativas en la variable «comunidad autónoma», la subescala DP en «población del municipio », «tipo de centro médico del municipio», «dispensaciones de productos de parafarmacia al día» y «facturación anual de la farmacia», y la subescala RP en «relaciones personales del farmacéutico » y «relaciones profesionales con el médico». Conclusiones: Se han obtenido niveles de burnout preocupantes, aunque inferiores a los de otras profesiones sanitarias, pero con mayor realización personal. Novedad del estudio: Se ha determinado por primera vez la afectación por síndrome de burnout de los farmacéuticos rurales de España (AU)
Objective: Measure by the Maslach Burnout Inventory (MBI) the three aspects of professional burnout, that allow to determine the extent of burn out worker syndrome (burnout) within the rural community pharmacists in Spain, correlating this with their socio-demographic characteristics and pharmaceutical care. Methodology: Transversal descriptive study with analytical components through self-administered surveys conducted by mail, addressed to a sample of head pharmacists in dispensing pharmacies in Spain from towns of up to 5,000 people. This stratified random sampling rate, was conducted in two waves, between June and November of 2009. A questionnaire that contained three types of variables was designed: socio-demographic, variables that allow characterizing the work of pharmacists in a rural pharmacy, and the 22 items of the MBI. The survey-based information was evaluated by descriptive analysis (frequencies, means and standard deviation) and an analytical approach based on simple analysis of variance and t-test of Student. Results: 9.52% of the pharmacists have burnout syndrome, and the values obtained for the three subscales, emotional exhaustion (EC), depersonalization (DP) and personal accomplishment (PA), showed average levels of affection for the three, with means and standard deviations of 16.4 (SD= 11.7), 5.4 (SD= 5.6) and 36.2 (SD= 9.3) respectively. The EC subscale showed significant differences within autonomous communities, DP within population of the town, type of medical center in the town, parapharmacy products dispensed daily and annual invoicing of the pharmacy. And PA pharmacists personal relationships and professional relationships with the physician. Conclusions: Worrying burnout levels have been obtained, albeit lower than those of other health professions, but with greater personal accomplishment. Latest news of the study: It has been determined for the first time the condition for burnout syndrome of rural pharmacists in Spain (AU)
Subject(s)
Humans , Male , Female , Burnout, Professional/complications , Burnout, Professional/diagnosis , Burnout, Professional/psychology , Pharmacies/organization & administration , Pharmacies/standards , Pharmacies , Surveys and Questionnaires , Surveys and Questionnaires/standards , 24419ABSTRACT
Alumina-zirconia nano-composites were recently developed as alternative bearing materials for orthopedics. Previous, preliminary reports show that such alumina-zirconia nanocomposites exhibit high crack resistance and low wear rate. In this paper, additional information is given in terms of wear, crack resistance and ageing behaviour: femoral heads are inspected after 7 million cycles of wear testing on a hip simulator, crack resistance is measured and compared to other ceramics used today in orthopedics, slow crack growth is reported under static and cyclic fatigue, and aging resistance is assessed. We also report on the load to failure of femoral heads prototypes during compression tests. This overall reliability assessment ensures a potential future development for these kinds of new nanocomposites in the orthopedic field.
Subject(s)
Materials Testing/methods , Nanocomposites , Orthopedics , Aluminum Oxide/chemistry , Ceramics/chemistry , Hip Joint/surgery , Hip Prosthesis , Luminescent Measurements , Microscopy, Atomic Force , Microscopy, Electron, Scanning , Prosthesis Failure , Stress, Mechanical , Time Factors , Zirconium/chemistryABSTRACT
Two different methods to obtain silver nanoparticles supported on kaolin crystals have been performed: the first one followed a thermal reduction and the second one a chemical reduction. In both cases, the silver nanoparticles with two different average particles size (ca.12 and 30 nm) were perfectly isolated and attached to the surface of the kaolin plates. The silver nanoparticles were localized mainly at the edge of the single crystal plates, the hydroxyl groups being the main centres of adsorption. The samples were fully characterized by XRD, UV-vis spectroscopy and TEM. The antimicrobial benefits of the composites were evaluated as antibacterial against common Gram-positive and Gram-negative bacteria, and antifungal activity against yeast. The results indicated a high antimicrobial activity for Escherichia coli JM 110 and Micrococcus luteus, while being inactive against yeast under our experimental conditions. The chemical analysis of Ag in the fermentation broths show that only a small portion of metal (<9 ppm) is released from the kaolin/metakaolin particles. Therefore, the risk of toxicity due to a high concentration of metal in the medium is minimized.
Subject(s)
Anti-Infective Agents/chemistry , Anti-Infective Agents/pharmacology , Kaolin/chemistry , Nanoparticles/chemistry , Silver/chemistry , Silver/pharmacology , Bacteria/drug effects , Chemical Precipitation , Nanoparticles/ultrastructure , Yeasts/drug effectsABSTRACT
A light scattering model under the Rayleigh-Gans-Debye approximation has been developed for polycristalline alumina. The model states that transmittance of dense alumina ceramics basically depends not only on the maximum grain size but also on the preferential orientation of their c-axis, or texture. The effect of texture in transparency has been experimentally measured on several dense alumina samples with different grain size and compared to that obtained from x-ray Rietveld refinements with a very good agreement. The Rayleigh-Gans-Debye approximation also allows to represent optical data in a very simple way (logarithm of transmittance vs. the inverse of the wavelength square). Using these variables, a straight line is obtained for the Rayleigh-Gans-Debye approximation, its slope being proportional to the maximum grain size and textural parameter. Deviation from this law implies the presence of pores or grain of extremely large size.
Subject(s)
Aluminum Oxide/chemistry , Models, Chemical , Nanospheres/chemistry , Nanospheres/ultrastructure , Nanotechnology/methods , Refractometry/methods , Anisotropy , Computer Simulation , Light , Scattering, RadiationABSTRACT
Isolated tungsten nanoparticles (α-W and ß-W phase) were synthesized and epitaxially grown on alumina and spinel particle surfaces with an average tungsten size of ≤20 nm for a low tungsten content (of ≤1.5 vol%). Using tungsten (VI) ethoxide alcoholic solutions, tungsten trioxide hydrated precursors were attached to a ceramic grains surface as a nanoparticle coating. High-resolution transmission electron microscopy (HRTEM) micrographs showed epitaxial interfaces between alumina, spinel and metallic tungsten. This epitaxial growth is assumed to be due to the effect of water vapour on the sublimation of ortho-tungstic acid during the reduction process in a hydrogen atmosphere. The planes involved in the epitaxy were found to be [Formula: see text] and [Formula: see text].
ABSTRACT
The use of ceramic-on-ceramic (alumina- and zirconia-based) couplings in hip joint prostheses has been reported to produce lower wear rates than other combinations (i.e., metal-on-polyethylene and ceramic-on-polyethylene). The addition of zirconia into an alumina matrix (zirconia-toughened alumina, ZTA) has been reported to result in an enhancement of flexural strength, fracture toughness, and fatigue resistance. The development of new processing routes in nonaqueous media has allowed to obtain high-density ZTA nanocomposites with a very homogeneous microstructure and a significantly smaller and narrower particle-size distribution of zirconia than conventional powder mixing methods. The aim of the present study was to set up and validate a new ZTA nanocomposite by testing its biocompatibility and wear behavior in a hip-joint simulator in comparison with commercial alumina and experimental alumina specimens. The primary osteoblast proliferation onto ZTA nanocomposite samples was found to be not significantly different from that onto commercial alumina samples. After 7 million cycles, no significant differences were observed between the wear behaviors of the three sets of cups. In this light, it can be affirmed that ZTA nanocomposite materials can offer the option of improving the lifetime and reliability of ceramic joint prostheses.
Subject(s)
Aluminum Oxide , Biocompatible Materials , Hip Prosthesis , Nanotechnology , ZirconiumABSTRACT
Oxide ceramics are sensitive to slow crack growth because adsorption of water can take place at the crack tip, leading to a strong decrease of the surface energy in humid (or air) conditions. This is a major drawback concerning demanding, long-term applications such as orthopaedic implants. Here we show that a specific nanostructuration of ceramic oxides can lead to a crack resistance never reached before, similar to that of covalent ceramics.
Subject(s)
Aluminum Oxide/chemistry , Biocompatible Materials/chemistry , Ceramics/chemistry , Crystallization/methods , Nanostructures/chemistry , Zirconium/chemistry , Aluminum Oxide/analysis , Biocompatible Materials/analysis , Ceramics/analysis , Hardness , Materials Testing , Molecular Conformation , Nanostructures/analysis , Oxides/analysis , Oxides/chemistry , Surface Properties , Water/chemistry , Zirconium/analysisABSTRACT
Mono-phase bio-ceramics (alumina and zirconia) are widely used as femoral heads in total hip replacements (THR) as an alternative to metal devices. Unfortunately, the orthopaedic community reports significant in-vivo failures. Material scientists are already familiar with composites like alumina zirconia. Since both are biocompatible, this could prove to be a new approach to implants. This paper deals with a new generation of alumina-zirconia nano-composites having a high resistance to crack propagation, and as a consequence may offer the option to improve lifetime and reliability of ceramic joint prostheses. The reliability of the above mentioned three bio-ceramics (alumina, zirconia and zirconia toughened alumina) for THR components is analysed based on the study of their slow crack-growth behaviour. The influence of the processing conditions on the microstructure development, of the zirconia toughened alumina composites and the effect of these microstructures, on its mechanical properties, are discussed.
