250 research outputs found
Characterizing the Physical and Chemical Mass Transport of Dissolved Salts in Layered Oil Sands Waste Undergoing Reclamation
This research aims to characterize the physical and chemical transport processes driving the distribution of dissolved salts in experimental reclamation scenarios that layer centrifuged fine tailings, petroleum coke, and reclamation material. Six field lysimeters were constructed at an oil sands mine near Fort McMurray, Alberta to assess various layering scenarios under both saturated and unsaturated conditions. Physical characteristics (temperature, water content), pore water geochemistry, and bulk mineralogy were characterized through collection of samples via multi- level monitoring wells, cores, and data loggers. Complimentary laboratory column experiments were set up to monitor the migration of dissolved ions over time, and conservative transport models developed as a means of assessing the major mass transport processes controlling salt distribution. Logger data and pore water chemistry revealed that self-weight consolidation and seasonal freeze- thaw cycles facilitate a volume change in the CFT that translates to an advective release of pore water toward the surface. Depth profiles of major ions and electrical conductivity consistently demonstrate that dissolved salt concentrations become elevated at the surface of saturated systems without a reclamation cover due to evaporation. Data suggests evaporative solute concentration has a larger influence on pore water chemistry in saturated systems. Measurable analyte concentrations were not observed near the surface of unsaturated systems with petroleum coke, due to a lack of available pore water to act as a vehicle for salt movement. Column experiments support the field data, suggesting that the saturated arrangements are at greater risk of surface salt accumulation than unsaturated complements. Both field and column experiments demonstrate that petroleum coke cannot host exchange reactions that mitigate dissolved salt migration. Modeling results support the idea that advection - hydrodynamic dispersion is the primary transport regime in early time due to initially rapid settlement of CFT. In the long-term, transport transitions to primarily diffusion dominated
Confirmation of symmetrical distributions of clinical attachment loss and tooth loss in a homogeneous Mexican adult male population
Background/purpose
To ascertain whether or not clinical attachment loss and tooth loss are present with similar severity and prevalence across the two sides of the mouth in a homogeneous sample of urban male adults.
Materials and methods
A cross-sectional study was carried out on 161 policemen (a largely homogeneous group in terms of ethnic background, socioeconomic status, sex, occupation, and medical/dental insurance) in Campeche, Mexico. Periodontal examinations were undertaken using the Florida Probe System in a dental chair by one trained and standardized examiner (kappa ≥ 0.60) to determine clinical attachment loss and tooth loss. We examined six sites in all teeth present in the mouth (a maximum of 168 sites, no third molars). Because of correlated data between observations, McNemar (for tooth loss) and Wilcoxon (for attachment loss) signed-rank tests were used to compare right and left sites within the same patient.
Results
The mean age was 38.4 ± 11.0 years. The mean number of teeth present was 24.4 ± 4.6; the mean number of periodontal sites/person was 146.7 ± 27.8. All P values were ≥ 0.05 (except for attachment loss in the upper first premolars), suggesting that there were no statistically significant differences between the right and left sides for the frequency of presentation of these two conditions.
Conclusion
Tooth loss and attachment loss measurements largely resemble each other on both sides of the mouth
Successful Treatment of Acute Prostatitis Caused by Multidrug-Resistant Escherichia coli With Tigecycline Monotherapy
We present a successful treatment, with tigecycline monotherapy, of acute prostatitis caused by multidrug-resistant Escherichia coli harboring an NDM-1 carbapemenase along with a CMY-2 cephalosporinase and a TEM ESBL
On the gamma-ray emission of W44 and its surroundings
We present the analysis of 9.7 years Fermi-LAT data of the middle-aged
supernova remnant W44 and the massive molecular gas complex that surrounds it.
We derived a high-quality spectral energy distribution of gamma-radiation of
the shell over three decades. The very hard spectrum below 1 GeV supports the
earlier claims regarding the hadronic origin of radiation. We also confirm the
presence of two extended -ray structures located at two opposite edges
of the remnant along its major axis. Based on the high-resolution gas maps, we
demonstrate that the gamma-ray structures are caused by the enhanced cosmic-ray
density rather than the gradient of the gas distribution. We argue that the
revealed cosmic-ray "clouds" suggest an anisotropic character of the escape of
high-energy particles from the shell along the magnetic field of the remnant
Meticillin-resistant Staphylococcus aureus Contact Screening Strategy in a Low Prevalence Setting; a Nested Case-Control Study.
Background
The optimal screening strategy in hospitals to identify secondary cases after contact with a meticillin-resistant Staphylococcus aureus (MRSA) index patient in a low prevalence setting is not well defined. We aimed at identifying factors associated with documented MRSA transmissions.
Method
Single center, retrospective, nested case-control study. We evaluated the screening strategy in our 950 bed tertiary care hospital from 2008 - 2014. Room and ward contacts of MRSA index patients present at time of MRSA identification were screened. We compared characteristics of Staphylococcus aureus Protein A (spa)-type matched contact patients (cases) to negative or spa-type mismatched contact patients (controls).
Results
Among 270,000 inpatients from 2008 - 2014, 215 MRSA screenings yielded 3013 contact patients, and 6 (0.2%) spa-type matched pairs. We included 225 controls for the nested case-control study. The contact type for the cases was more frequently "same room" and less frequently "same ward" compared with the controls (P = 0.001). Also, exposure time was longer for cases (median of 6 days [IQR 3-9]) than for controls (1 day [0-3], P=0.016).
Conclusion
The extensive MRSA screening strategy revealed only few index/contact matches based on spa-typing. Prolonged exposure time and a shared room were significantly associated with MRSA transmission. A targeted screening strategy may be more useful in a low prevalence setting than screening entire wards
Revision de casos, estudio inmunohistoquimico y expresion del CKIT en Melanomas de mucosa sinonasal, diagnosticados en los hospitales Clinico Universitario "Lozano Blesa" de Zaragoza y Complejo Hospitalario de Navarra en Pamplona, desde 1990 hasta 2016.
Los melanomas de mucosa sinonasal (SNMM) son entidades agresivas e infrecuentes, originadas en melanocitos presentes en el epitelio y estroma de la mucosa respiratoria. El diagnóstico es complicado debido a su morfología, distintos patrones arquitecturales/citológicos y ocasional ausencia de pigmento melánico. La mutación KIT, identificada en melanomas en 2004, esta descrita en aproximadamente 15-30% de los melanomas acrales y mucosos. Su estudio, plantea aprovechar el potencial terapéutico de fármacos inhibidores de la tirosinquinasa. Se revisaron los casos de SNMM, en los servicios de anatomía patológica de los Hospitales Clínico Universitario “Lozano Blesa” de Zaragoza y Complejo Hospitalario de Navarra en Pamplona, entre enero 1990 y junio 2016. Se estudiaron histológico e Inmunohistoquímicamente, incluyendo la técnica CKIT/CD117. Se recopilaron seis casos, cuatro epitelioides, un fusocelular y un plasmocitoide, todos ellos diagnosticados en adultos/ancianos, con características acordes a las descritas en la literatura. La expresión del CKIT (CD117) fue positiva en todos los casos. El tratamiento de elección fue la cirugía en todos los pacientes, algunos con posterior radioterapia. La sobrevida no fue mayor a tres años. Se plantea la utilidad de la tinción inmunohistoquímica como posible complemento al panel diagnóstico, el estudio mediante FISH para confirmar la presencia de la mutación y considerar una probable connotación terapéutica con inhibidores de la tirosinquinasa
Estudio geomecánico-geotécnico para el diseño de estabilidad de taludes, entre la progresiva del 07+580 al km 08+970, de la carretera Choropampa- Asunción, sector Salabamba, Cajamarca-2021
La presente investigación se centra en el estudio geomecánico-geotécnico para el diseño de estabilidad de taludes, entre la progresiva del km 07+580 al km 08+970, de la carretera Choropampa-Asunción, sector Salabamba, Cajamarca 2021, ubicada al sur Oeste de la ciudad de Cajamarca, conformada por las Formaciones: Inca, Chulec y Farrat pertenecientes al Mesozoico del cretáceo inferior del Grupo Goyllarisquizga, además de evidenciar estructuras fuertemente disturbadas, fósiles, fallamientos, plegamientos y alto fracturamiento. Se establecieron 30 taludes para el análisis geomecánico-geotécnico, los taludes de roca tuvieron una calificación de 30.47 en RMR siendo de clase V calidad malo y promedio de 49.9 en GSI indicando una condición media, así también se evidencia en 4 estaciones, fallas de tipo cuña y vuelco con un SMR promedio de 44.25; los taludes tipo suelo se identificó dos tipos, el aluvial, formado por areniscas con limos, y el coluvial, formado por gravas, margas y escasas areniscas, estos 30 taludes presentan un alto grado de erosión debido a la acción antrópica y altas precipitaciones de la zona. Se hizo el análisis de estabilidad basados en el factor de seguridad y ayudados del software Slide V6 y Autocad 2019, se determinó que en condiciones estáticas hay 16 taludes tipo roca y los taludes suelos todos inestables, mientras que en condiciones seudoestáticas con factor sísmico de 0.35, 19 taludes tipo roca y los taludes en suelo son inestables, los controles a realizar es el aplicar el método de terraceo para algunos taludes, corte y relleno de material, construyendo bermas cada una con ángulo de inclinación, ancho y altura diferente, para otros taludes anclajes de diferente longitud y capacidad de carga, en algunas estaciones una mezcla de los dos métodos (terraceo y anclajes), además de aplicar distribución de fuerzas en algunas bermas y realizar captación de niveles de agua e instalación de drenajes para evitar la filtración en el talud, siendo la zona de estudio, área de alta vulnerabilidad para la población
Characterization of hybrid biocomposite Poly-Butyl-Succinate/Carbon fibers/Flax fibers
The investigation of renewable and recyclable materials becomes more critical every day due to the high levels of
waste and carbon emissions and their impact on the environment. The use of eco-friendly materials, such as
natural fibers and bioplastics, is increasingly important, and their use is always more popular. The aim of this
research is to evaluate the changes in properties of composite materials made of Poly-Butyl-Succinate (PBS), a
biodegradable thermoplastic matrix, and carbon fiber when some layers of carbon fiber are replaced by some
layers of flax fiber to create a hybrid composite; in order to obtain a material more environmentally friendly with
similar mechanical properties. To modify the flax fiber’s surface energy and improve the wettability with the PBS
matrix, an Atmospheric Pressure Plasma Torch (APPT) treatment was performed. The fibers’ surfaces were
characterized by measuring the contact angle; the contact angle values confirmed the wettability and accordingly,
adhesion increased after plasma treatment. Different experiments were performed after substituting carbon
fibers to evaluate the changes in the composite material’s mechanical and thermal properties: tensile test, threepoint
bending test, impact tests and differential scanning calorimetry. Replacing the carbon fiber core layer with
one or two flax fiber layers did not compromise the thermal stability. It led to the manufacturing of a hybrid
composite with improved mechanical properties and higher impact resistance.This work has been supported by Comunidad de Madrid (Spain) - multiannual agreement with UC3M ("Excelencia para el Profesorado Universitario"; - EPUC3M04) - Fifth regional research plan 2016-202
Contribution of prosthetic treatment considerations for dental extractions of permanent teeth
Background. Tooth loss is an easily identifiable outcome that summarizes a complex suite of factors in an individual’s history of dental disease and its treatment by dental services over a lifetime. Assessment of overall tooth loss data is essential for epidemiologically evaluating the adequacy of dental care provided at a systems level, as well as for placing in context tooth loss for non-disease causes. For example, when derived from prosthetic treatment planning, the latter may unfortunately lead to some teeth being extracted (pulled) for the sake of better comprehensive clinical results. The objective of the present manuscript was to identify the contribution to overall tooth loss, by extraction of permanent teeth because of prosthetic treatment reasons.
Material and Methods. A cross-sectional study included sex, age, total number of extractions performed by subject, sextant (anterior vs. posterior), group of teeth (incisors, canines, premolars and molars), upper or lower arch, and the main reason underlying extraction (extraction for any reason vs. prosthetic treatment), in patients 18 years of age and older seeking care at a dental school clinic in Mexico. A multivariate logistic regression model was generated.
Results. A total of 749 teeth were extracted in 331 patients; 161 teeth (21.5% of total) were extracted for explicit prosthetic treatment indications. As age increased, the likelihood of having an extraction for prosthetic reasons increased 3% (OR = 1.03, p < 0.001). Women (OR = 1.57, p < 0.05) were more likely to be in this situation, and molars (OR = 2.70, p < 0.001) were most at risk. As the total number of extractions increased, the risk of having an extraction for prosthetic reasons decreased (OR = 0.94, p < 0.05).
Conclusions. A significant amount (21.5%) of the extractions of permanent teeth were performed for prosthetic reasons in this dental school clinical environment; age, sex, type of tooth, and the total number of extractions moderated such pattern
Prevalence of Functional Dentition in a Group of Mexican Adult Males
Objective: To determine the prevalence of functional dentition and associated periodontal variables in a sample of Mexican adult males. Methods: A cross-sectional study of 161 policemen in Campeche, Mexico, was carried out. A clinical examination using an electronic probe was used to collect variables (dental plaque, periodontal pockets, gingival recession, suppuration, and bleeding on probing) on 6 periodontal sites (a maximum of 168 sites, excluding third molars). Sociodemographic, socioeconomic, and behavioral variables were collected through a self-administered survey. Functional dentition was defined as having 21 or more natural teeth. Data were analyzed with STATA 11.0, using logistic regression models. Results: Mean age was 38.3 (±10.9) years. The prevalence of having a functional dentition was 83.8% in the sample. The odds of having a functional dentition declined with age (odds ratio [OR] = 0.93), having diabetes (OR = 0.27) and with having a high percentage of sites with plaque (OR = 0.77), with bleeding on probing (OR = 0.97), and with gingival recession (OR = 0.82). Conclusion: While a large proportion of subjects had a functional dentition in this community-dwelling sample of adult Mexican males, the likelihood of their having a functional dentition decreased with age, with their having been diagnosed with diabetes, and with assorted negative indicators of periodontal/gingival status
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