Acrylic bone cements modified with graphene oxide: Mechanical, physical, and antibacterial properties

Bacterial infections are a common complication after total joint replacements (TJRs), the treatment of which is usually based on the application of antibiotic-loaded cements; however, owing to the increase in antibiotic-resistant microorganisms, the possibility of studying new antibacterial agents in acrylic bone cements (ABCs) is open. In this study, the antibacterial effect of formulations of ABCs loaded with graphene oxide (GO) between 0 and 0.5 wt. % was evaluated against Gram-positive bacteria: Bacillus cereus and Staphylococcus aureus, and Gram-negative ones: Salmonella enterica and Escherichia coli. It was found that the effect of GO was dependent on the concentration and type of bacteria: GO loadings ≥0.2 wt. % presented total inhibition of Gram-negative bacteria, while GO loadings ≥0.3 wt. % was necessary to achieve the same effect with Gram-positives bacteria. Additionally, the evaluation of some physical and mechanical properties showed that the presence of GO in cement formulations increased wettability by 17%, reduced maximum temperature during polymerization by 19%, increased setting time by 40%, and increased compressive and flexural mechanical properties by up to 17%, all of which are desirable behaviors in ABCs. The formulation of ABC loading with 0.3 wt. % GO showed great potential for use as a bone cement with antibacterial properties

Toward an operative diagnosis in sepsis: a latent class approach

<p>Abstract</p> <p>Background</p> <p>Recent data have suggested that 18 million of new sepsis cases occur each year worldwide, with a mortality rate of almost 30%. There is not consensus on the clinical definition of sepsis and, because of lack of training or simply unawareness, clinicians often miss or delay this diagnosis. This is especially worrying; since there is strong evidence supporting that early treatment is associated with greater clinical success. There are some difficulties for sepsis diagnosis such as the lack of an appropriate gold standard to identify this clinical condition. This situation has hampered the assessment of the accuracy of clinical signs and biomarkers to diagnose sepsis.</p> <p>Methods/design</p> <p>Cross-sectional study to determine the operative characteristics of three biological markers of inflammation and coagulation (D-dimer, C-reactive protein and Procalcitonin) as diagnostic tests for sepsis, in patients admitted to hospital care with a presumptive infection as main diagnosis.</p> <p>Discussion</p> <p>There are alternative techniques that have been used to assess the accuracy of tests without gold standards, and they have been widely used in clinical disciplines such as psychiatry, even though they have not been tested in sepsis diagnosis. Considering the main importance of diagnosis as early as possible, we propose a latent class analysis to evaluate the accuracy of three biomarkers to diagnose sepsis.</p

Nurses' perceptions of aids and obstacles to the provision of optimal end of life care in ICU

Contains fulltext : 172380.pdf (publisher's version ) (Open Access

2011 6th Colombian Computing Congress, CCC 2011

593628

Kernel-based framework for spectral dimensionality reduction and clustering formulation: A theoretical study

This work outlines a unified formulation to represent spectral approaches for both dimensionality reduction and clustering. Proposed formulation starts with a generic latent variable model in terms of the projected input data matrix.Particularly, such a projection maps data onto a unknown high-dimensional space. Regarding this model, a generalized optimization problem is stated using quadratic formulations and a least-squares support vector machine.The solution of the optimization is addressed through a primal-dual scheme.Once latent variables and parameters are determined, the resultant model outputs a versatile projected matrix able to represent data in a low-dimensional space, as well as to provide information about clusters. Particularly, proposedformulation yields solutions for kernel spectral clustering and weighted-kernel principal component analysis

Chitosan Beads Incorporated with Essential Oil of Thymus capitatus: Stability Studies on Red Tilapia Fillets

Red Tilapia is one of the most consumed but perishable fish in the world. As a result, it requires preservation methods for safe consumption without affecting its organoleptic characteristics. Chitosan encapsulating essential oils have shown to be an excellent food conservation method. For that reason, we carried out the study of the protective effect on red Tilapia fillets with chitosan beads (CB) incorporated with Thymus capitatus (TCEO) essential oil at 500, 1000, and 2000 mg/L to assess the conservation of the fillets. The TCEO composition was characterized by gas chromatography-mass spectrometry (CG-MS). For the other side, CB was characterized by Fourier transform infrared spectroscopy (FTIR), X-ray diffraction spectroscopy (XRD), thermogravimetric analysis (TGA), and Scanning electron microscopy (SEM). The protective effect of the beads was tested against the Gram-positive and Gram-negative bacteria growth for four weeks. The results showed an inhibition effect in Gram-positive bacteria at higher TCEO concentration (1000 and 2000 mg/L). Besides that, the pH, total volatile basic nitrogen (T-BNV-N), color, and fillet texture were evaluated as quality attributes. The results suggested that the incorporation of the CB-TCEO allowed a higher contact of the active compounds with the food surface, which reflected more excellent stability. The quality attributes of the fillets were preserved for 26 days, suggesting its uses for the treatment for perishable food

Análisis markoviano de un proceso de estancia hospitalaria en un hospital de tercer nivel de complejidad

Objetivo: estimar el número esperado de pacientes con trauma en los servicios de hospitalización, cirugía y unidad de cuidados intensivos y en la condición de egreso vivo y muerto, luego de ingresar por urgencias a un hospital de tercer nivel de complejidad. Materiales y métodos: con base en la información derivada de un estudio de seguimiento con 2.084 registros correspondientes a ingresos a urgencias por trauma en un hospital de tercer nivel de complejidad, se estimó la matriz de probabilidades de transición y el número esperado de pacientes en cada estado en una unidad de tiempo de 12 horas para todas las cohortes de pacientes, mediante el análisis de cadenas de Markov. Resultados: se obtuvo un análisis de sensibilidad para la probabilidad de permanecer en el servicio de cirugía y de ser trasladado de la unidad de cuidados intensivos a hospitalización. Conclusión: el modelo utilizado es adecuado para la reproducción de lo observado y puede utilizarse para predecir configuraciones observables si se conoce el ritmo de ingreso de las cohortes de pacientes o si se tiene un modelo teórico para ellas

Evaluation of the chitosan films of essential oils from Origanum vulgare L (oregano) and Rosmarinus officinalis L (rosemary)

Abstract Introduction: In recent years, the demand for safe materials derived from biodegradable compounds has increased in order to prolong the shelf life of food. Chitosan is a biological macromolecule that has been used alone or in combination with natural ingredients such as essential oils for its ability to prolong the shelf life of foods, represented by high antimicrobial and antioxidant properties. Origanum vulgare L. (Lamiaceae) and Rosmarinus officinalis L. (Lamiaceae) are two of the traditional plants used in Colombia for medicinal and nutritional purposes due to their bioactive and organoleptic properties. Objective: Research the blending of essential oils of O. vulgare and R. officinalis Colombian varieties with chitosan films, to introduce antioxidant and antimicrobial properties of chitosan films to prevent spoilage and deterioration of food. Methods: Chitosan films incorporated with essential oils were obtained. The essential oils were extracted by hydrodistillation of the leaves of Origanum vulgare L. and Rosmarinus officinalis L. and incorporated into the films in concentrations of 0.4 and 1.5% (v/v), their mechanical properties, total content of phenols (TPC), antioxidant capacity and antibacterial capacity against Escherichia coli K-12 MG 1655 and Bacillus subtillis 102 were evaluated. Results: It was found that the introduction of the essential oils in the chitosan matrix decreases the mechanical properties of the films (tensile strength), increases the opacity (Y) and the total content of phenols (TPC), improves the antioxidant and antibacterial properties of the films Conclusion: The results suggest that the presence of essential oils of R. officinalis and O. vulgare can increase the antioxidant and antimicrobial properties of the films, useful properties for the preservation of foods, suggesting them as an interesting method for packaging applications. However, future experiments should consider the interactions of films with food to understand their effect on sensorial properties