RESUMEN
Zeolites have been found to be promising sensor materials for a variety of gas molecules such as NH3, NOx, hydrocarbons, etc. The sensing effect results from the interaction of the adsorbed gas molecules with mobile cations, which are non-covalently bound to the zeolite lattice. The mobility of the cations can be accessed by electrical low-frequency (LF; mHz to MHz) and high-frequency (HF; GHz) impedance measurements. Recent developments allow in situ monitoring of catalytic reactions on proton-conducting zeolites used as catalysts. The combination of such in situ impedance measurements with diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS), which was applied to monitor the selective catalytic reduction of nitrogen oxides (DeNOx-SCR), not only improves our understanding of the sensing properties of zeolite catalysts from integral electric signal to molecular processes, but also bridges the length scales being studied, from centimeters to nanometers. In this work, recent developments of zeolite-based, impedimetric sensors for automotive exhaust gases, in particular NH3, are summarized. The electrical response to NH3 obtained from LF impedance measurements will be compared with that from HF impedance measurements, and correlated with the infrared spectroscopic characteristics obtained from the DRIFTS studies of molecules involved in the catalytic conversion. The future perspectives, which arise from the combination of these methods, will be discussed.
RESUMEN
BACKGROUND AND AIMS: Osteoarthritis (OA) is the world's most common joint disease and there is currently no cure. Glenohumeral osteoarthritis (GHOA) accounts for an estimated 5%-17% of patients with shoulder complaints. The etiology of GHOA is multifactorial, and we review the various non-specific and specific risk factors and further sub-classify them into local and systemic factors. MATERIALS AND METHODS: Data for this review article were identified by searches of MEDLINE, PubMed, and references from relevant articles using search terms such as "glenohumeral," "osteoarthritis," "epidemiology," "etiology," "imaging," and "pathophysiology." Only articles published in English, German, and Finnish between 1957 and 2017 were included. RESULTS: The prevalence of radiological shoulder OA has been estimated to be as high as 16%-20% in the middle-aged and elderly population, but the concordance between structural findings and symptoms seems to be weak, as many of these individuals are asymptomatic. The vast majority of GHOA is related to non-specific factors, namely advancing age, while specific risk factors are commonly found in young patients. Diagnosis of GHOA is made when typical clinical features and defined radiological findings overlap in an individual. CONCLUSION: Conclusion: Ultimately the determinants of shoulder pain in GHOA remain incompletely understood. Improved understanding of the etiology and diagnosis of GHOA will enable clinicians to better determine which patients will benefit from different treatment modalities, as well as provide new avenues to potential treatments.
Asunto(s)
Osteoartritis , Articulación del Hombro , Anciano , Humanos , Persona de Mediana Edad , Osteoartritis/diagnóstico por imagen , Osteoartritis/epidemiología , Radiografía , Articulación del Hombro/diagnóstico por imagenRESUMEN
BACKGROUND: Recent mass-casualty events have exposed errors with common assumptions about response proc-esses, notably triage and transport of patients. Response planners generally assume that the majority of patients from a mass-casualty event will have received some level of field triage and transport from the scene to the hospital will have been coordinated through on-scene incident command. When this is not the case, emergency response at the hospital is hampered as staff must be pulled to handle the influx of untriaged patients. OBJECTIVE: Determine whether the use of emergency medical service (EMS) field resources in hospital triage could enhance the overall response to active-shooter and other mass-casualty events. DESIGN: A proof of concept study was planned in conjunction with a regularly scheduled mass-casualty hospital ex-ercise conducted by an urban level II trauma center in Utah. This was a cross-over study with triage initially performed by hospital staff, and at the midpoint of the exercise, triage was transferred to EMS field units. General performance was judged by exercise planners with limited additional data collection. RESULTS: EMS crews at the hospital significantly enhanced the efficiency and efficacy of the triage operation in both qualitative and quantitative assessment. CONCLUSIONS: Hospital planners deemed the proof of concept exercise a success and are now experimenting with implementation of this alternate approach to triage. However, much additional work remains to fully implement this change in processes.
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Planificación en Desastres/organización & administración , Servicios Médicos de Urgencia/organización & administración , Servicio de Urgencia en Hospital/organización & administración , Incidentes con Víctimas en Masa , Triaje/organización & administración , Estudios Cruzados , HumanosRESUMEN
A home care agency's patient population with heart failure demonstrated improved outcomes after the agency implemented an evidence-based protocol. The model holds promise for use in other agencies working to improve patient outcomes as well as have an impact on decreasing costs.
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Enfermería en Salud Comunitaria/economía , Enfermería en Salud Comunitaria/normas , Medicina Basada en la Evidencia , Insuficiencia Cardíaca/enfermería , Servicios de Atención de Salud a Domicilio/organización & administración , Guías de Práctica Clínica como Asunto , Ahorro de Costo , Análisis Costo-Beneficio , Femenino , Insuficiencia Cardíaca/diagnóstico , Humanos , Relaciones Interinstitucionales , Masculino , Modelos de Enfermería , Investigación en Evaluación de Enfermería , Competencia Profesional , Sensibilidad y Especificidad , Gestión de la Calidad TotalRESUMEN
In a proof-of-concept study we demonstrate in situ reaction monitoring of DeNO(x)-SCR on proton-conducting zeolites serving as catalyst and gas sensor at the same time. By means of temperature-dependent impedance spectroscopy we found that the thermally induced NH(3) desorption in H-form and in Fe-loaded zeolite H-ZSM-5 follow the same process, while a remarkable difference under DeNO(x)-SCR reaction conditions was found. The Fe-loaded catalyst shows a significantly lower onset temperature, and time-dependent measurements suggest different SCR reaction mechanisms for the two catalysts tested. These results may help in the development of catalysts for the reduction of NO(x) emissions and ammonia consumption, and provide insight into the elementary catalytic process promoting a full description of the NH(3)-SCR reaction system.