Expiration Date Effect on Mechanical and Chemical Properties of Glass Ionomer Cements

ABSTRACT: The glass ionomer cements (GICs) is a generic name given to a group of materials widely used in clinical dentistry which if used after the specified expiration date, material properties may be affected. to evaluate the Vick ers microhardness, surface morphology and the energy dispersive X-ray microanalysis (EDX), of GICs with different expiration dates that were stored at room temperature. specimens of highly viscous glass ionomer cement (HVGIC) (Ketac Cem and Ketac Molar) and resin-modified glass ionomer cement (RMGIC) (Vitrebond) with different expiration dates (current, close to their expiration and expired) were prepared for Vickers microhardness test and scanning electronic microscopy (SEM) with EDX, measuring 5 mm in diameter and 2 mm length, per the manufacturer's instructions, in standard cylindrical teflon molds. For the comparison of obtained values, the ANOVA test was used, while Tukey test was used for the multiple comparisons. In all the GICs used, the microhardness decreased as the expiration date approached, finding a significant statistical differen ce (P<0.05) in Ketac Molar and Vitrebond. SEM sample analysis revealed similar cohesive cracks in all tested materials. The EDX analysis revealed the presence of the elements F, Al and Si in all GICs and Ca only in Ketac Molar and Ketac Cem. The elements were found in a higher atomic percentage in the GICs with an current date and in a lower percentage in those with an expired date. HVGIC and RMGIC with an expiration date finish and that were stored at room temperature, suffer significant physical and chemical changes, which could put doubts its clinical effectiveness.

RESUMEN: El cemento de ionómero de vidrio (CIV) es un nombre genérico que se le da a un grupo de materiales ampliamente utilizados en odontología clínica que si se usan después de la fecha de vencimiento especificada, las propiedades del material pueden verse afectadas. evaluar la microdureza Vickers, la morfología superficial y el microanálisis de energía dispersa de rayos X (EDX), de CIV con diferentes fechas de caducidad almacenados a temperatura ambiente. Muestras de cemento de ionómero de vidrio de alta viscosidad (CIVAV) (Ketac Cem y Ketac Molar) y cemento de ionómero de vidrio modificado con resina (CIVMR) (Vitrebond) con diferentes fechas de vencimiento (vigente, próximo a su vencimiento y vencido) de 5 x 2 mm, fueron preparadas para microscopía electrónica de barrido (MEB) con EDX y microdureza Vickers, según las instrucciones del fabricante, en moldes de teflón cilíndricos estándar. Para la comparación de los valores obtenidos se utilizó la prueba ANOVA, mientras que para las comparaciones múltiples se utilizó la prueba de Tukey. En todos los CIV utilizados, la microdureza disminuyó a medida que se acercaba la fecha de vencimiento, encontrándose una diferencia estadística significativa (P <0.05) en Ketac Molar y Vitrebond. El análisis de la muestra en MEB reveló grietas cohesivas similares en todos los materiales probados. El análisis EDX reveló la presencia de los elementos F, Al y Si en todos los GIC y Ca solo en Ketac Molar y Ketac Cem. Los elementos se encontraron en mayor porcentaje atómico en los GIC con fecha vigente y en menor porcentaje en aquellos con una fecha vencida. Los CIVAV y CIVMR con fecha de caducidad vencida y que fueron alma- cenados a temperatura ambiente, sufrieron cambios físicos y químicos importantes, lo que podría poner en duda su efectividad clínica.

Evaluation of biodegradable polymers as encapsulating agents for the development of a urea controlled-release fertilizer using biochar as support material.

Biochar constitutes a promising support material for the formulation of controlled-release fertilizers (CRFs). In this study we evaluated the effect of different polymeric materials as encapsulating agents to control nitrogen (N) leaching from biochar based CRFs. Nitrogen impregnation onto biochar was performed in a batch reactor using urea as N source. The resulting product was encapsulated by using sodium alginate (SA), cellulose acetate (CA) and ethyl cellulose (EC). Leaching potential was studied in planted and unplanted soil columns, monitoring nitrate, nitrite, ammonium and urea concentrations. After 90 days, plants were removed from the soil columns and plant yield was evaluated. It was observed that the ammonium concentration in leachates presented a maximum concentration for all treatments at day 22. The highest concentration of N in the leachates was the nitrate form. The crop yield was negatively affected by all developed CRFs using biochar compared with the traditional fertilization.

LC-MS/MS quantitative analysis of reducing carbohydrates in soil solutions extracted from crop rhizospheres.

A simple, sensitive, and specific analytical method has been developed for the quantitative determination of 15 reducing carbohydrates in the soil solution of crop rhizosphere. Reducing carbohydrates were derivatized with 1-phenyl-3-methyl-5-pyrazolone, separated by reversed-phase high-performance liquid chromatography and detected by electrospray ionization tandem mass spectrometry. Lower limits of quantitation of 2 ng/mL were achieved for all carbohydrates. Quantitation was performed using peak area ratios (analyte/internal standard) and a calibration curve spiked in water with glucose-d(2) as the internal standard. Calibration curves showed excellent linearity over the range 2-100 ng/mL (10-1,000 ng/mL for glucose). The method has been tested with quality control samples spiked in water and soil solution samples obtained from the rhizosphere of wheat and canola and has been found to provide accurate and precise results.

[Evaluation of the social care program for persons with severe mental disorders: a Delphi study]. / Valoración del programa social de atención a personas con trastorno mental grave: un estudio Delphi.

BACKGROUND: In January 2005 the Government of Navarre approved the "Care Program for Persons with Severe Mental Disorder" (PA-TMG). This article is intended to ascertain the opinion of experts regarding the PA-TMG. To identify the elements of agreement in the evaluation of positive aspects and aspects that can be improved. To make recommendations on the basis of their opinions. METHODS: A Delphi study was designed with 34 experts in health or social care of mentally ill persons. By means of repeated questionnaires, ideas that achieved a consensus of (3)90% were identified and a level of priority was assigned. The percentages of agreement and descriptive statistics of priority were presented, and the recommendations of analysis of the areas of consensus were drawn up. RESULTS: Out of the 34 participating experts, 25 (71.4%) completed the study: 1 sociologist, 5 social workers, 3 psychiatrists, 5 psychologists, one representative of the families, 3 occupational therapists, 1 technician in social integration and 6 family doctors. Sixty-four percent evaluated the Plan positively, and 72% were of the opinion that it was drawn up without sufficient professional participation. All thought that it could be improved by widening the participation of experts. CONCLUSIONS: The principal ideas on which there was consensus were: socio-health care must be guaranteed by the public administration; good systems of information and evaluation must be established; the Plan must have its own budget; professional follow-up of the patient by the different mechanisms must be guaranteed; a lot of the decision making must be decentralised; access to social benefits for these patients must be universalised.

Valoración del programa social de atención a personas con trastorno mental grave: un estudio Delphi / Evaluation of the social care program for persons with severe mental disorders: a Delphi study

Fundamento. En enero de 2005 el Gobierno de Navarra aprobó el “Programa de Atención a Personas con Trastorno Mental Grave” (PA-TMG). El objetivo del presente trabajo es conocer la opinión de expertos acerca del PA-TMG. Identificar los elementos de acuerdo en la valoración de aspectos positivos y aspectos mejorables. Realizar recomendaciones a partir de su opinión. Material y métodos. Se diseñó un estudio Delphi con 34 expertos en la atención sanitaria o social de enfermos mentales. Mediante cuestionarios repetidos se identificaron las ideas que alcanzaran un consenso >=90%, y se asignó un nivel de prioridad. Se presentan los porcentajes de acuerdo, estadísticos descriptivos de la prioridad, y se elaboran las recomendaciones de análisis de las áreas de consenso. Resultados. De los 34 expertos participantes, finalizaron el estudio 25 (71,4%): 1 socióloga, 5 trabajadoras sociales, 3 psiquiatras, 5 psicólogos, 1 representante de las familias, 3 terapeutas ocupacionales, 1 técnico en integración social y 6 médicos de familia. Valoran positivamente el Plan el 64% y 72% opinan que se ha elaborado sin suficiente participación profesional. Todos piensan que podría mejorarse si se amplia la participación de expertos. Conclusiones. Las principales ideas consensuadas han sido que: la atención socio-sanitaria debe garantizarse por los poderes públicos; se deben establecer buenos sistemas de información y de evaluación; el Plan debe tener presupuesto propio; debe garantizar el seguimiento profesional del paciente por los diferentes dispositivos; se deben descentralizar muchas tomas de decisiones; se debe universalizar el acceso a un catálogo de prestaciones sociales para estos enfermos

Background. In January 2005 the Government of Navarre approved the “Care Program for Persons with Severe Mental Disorder” (PA-TMG). This article is intended to ascertain the opinion of experts regarding the PA-TMG. To identify the elements of agreement in the evaluation of positive aspects and aspects that can be improved. To make recommendations on the basis of their opinions. Methods. A Delphi study was designed with 34 experts in health or social care of mentally ill persons. By means of repeated questionnaires, ideas that achieved a consensus of >=90% were identified and a level of priority was assigned. The percentages of agreement and descriptive statistics of priority were presented, and the recommendations of analysis of the areas of consensus were drawn up. Results. Out of the 34 participating experts, 25 (71.4%) completed the study: 1 sociologist, 5 social workers, 3 psychiatrists, 5 psychologists, one representative of the families, 3 occupational therapists, 1 technician in social integration and 6 family doctors. Sixty-four percent evaluated the Plan positively, and 72% were of the opinion that it was drawn up without sufficient professional participation. All thought that it could be improved by widening the participation of experts. Conclusions. The principal ideas on which there was consensus were: socio-health care must be guaranteed by the public administration; good systems of information and evaluation must be established; the Plan must have its own budget; professional follow-up of the patient by the different mechanisms must be guaranteed; a lot of the decision making must be decentralised; access to social benefits for these patients must be universalised

Preparation and characterization of activated carbon derived from the thermo-chemical conversion of chicken manure.

Physico-chemical properties of a bioorganic char were modified by pyrolysis in the presence of NaOH, and with subsequent physical activation of carbonaceous species with CO2 a value-added activated carbon was fabricated. Bioorganic char is produced as a co-product during the production of bio-fuel from the pyrolysis of chicken litter. Untreated char contains approximately 37 wt% of C and approximately 43-45 wt% of inorganic minerals containing K, Ca, Fe, P, Cu, Mg, and Si. Carbonization and chemical activation of the char at 600 degrees C in the presence of NaOH in forming gas (4% H2 balanced with Ar) produced mainly demineralized activated carbon having BET (Brunauer, Emmett, and Teller) surface area of 486 m2/g and average pore size of 2.8 nm. Further physical activation with CO2 at 800 degrees C for 30 min resulted in activated carbon with BET surface area of 788 m2/g and average pore size of 2.2 nm. The mineral content was 10 wt%. X-ray photoelectron spectroscopy (XPS) indicated that the latter activation process reduced the pyrrolic- and/or pyridonic-N, increased pyridinic-N and formed quaternary-N at the expense of pyrrolic- and/or pyridonic-N found in the untreated char.

Sorption of herbicides in relation to soil variability and landscape position.

Using the soil-water sorption partitioning coefficient (Kd), this study quantified the spatial variation of 2,4-D sorption by soil in an undulating-to-hummocky terrain landscape near Minnedosa, MB, Canada. Herbicide sorption was most strongly related to soil organic matter content and slope position, with greatest sorption occurring in lower landscape positions with greater soil organic matter content. The relation between sorption and slope position was more pronounced under conventional tillage (CT) than under long-term zero-tillage (ZT). Using multivariate regression and three independent variables (soil organic matter content, soil clay content and soil pH), the prediction of herbicide sorption by soil was very good for CT (R2 = 0.89) and adequately for ZT (R2 = 0.53).