Gas-solid contactors and catalytic reactors with direct microwave heating: current status and perspectives

Microwave heating (MWH) transforms energy from an electromagnetic wave to heat. In contrast to conventional heating (CH) mechanisms that use slower heat transfer processes via conduction, convection or radiation, microwaves (MW) directly interact with MW susceptor materials and induce a rapid conversion of the electromagnetic energy into heat. This rapid heating provides MWH with distinct features that can be leveraged to increase conversion, selectivity and/or energy efficiency of chemical processes. Here we discuss recent significant advances reported in MWH processes involving gas-solid interactions. Special attention is devoted to key aspects such as the methodologies to accurately determine local temperatures under the influence of electromagnetic (EM). Other relevant aspects such as the consideration of the solid catalyst dielectric properties or the design of novel gas-solid contactor configurations will be discussed. Emerging aspects such as the potential of MWH to minimize secondary by-products in high temperature reactions or to efficiently perform in transient processes, e.g. adsorption-desorption cycles, are highlighted. Finally, current challenges and perspectives towards a wide application of MWH in gas solid contactors will be critically discussed

Cost-utility of a walking programme for moderately depressed, obese, or overweight elderly women in primary care: a randomised controlled trial

<p>Abstract</p> <p>Background</p> <p>There is a considerable public health burden due to physical inactivity, because it is a major independent risk factor for several diseases (e.g., type 2 diabetes, cardiovascular disease, moderate mood disorders neurotic diseases such as depression, etc.). This study assesses the cost utility of the adding a supervised walking programme to the standard "best primary care" for overweight, moderately obese, or moderately depressed elderly women.</p> <p>Methods</p> <p>One-hundred six participants were randomly assigned to an interventional group (n = 55) or a control group (n = 51). The intervention consisted of an invitation, from a general practitioner, to participate in a 6-month walking-based, supervised exercise program with three 50-minute sessions per week. The main outcome measures were the healthcare costs from the Health System perspective and quality adjusted life years (QALYs) using EuroQol (EQ-5D.)</p> <p>Results</p> <p>Of the patients invited to participate in the program, 79% were successfully recruited, and 86% of the participants in the exercise group completed the programme. Over 6 months, the mean treatment cost per patient in the exercise group was €41 more than "best care". The mean incremental QALY of intervention was 0.132 (95% CI: 0.104–0.286). Each extra QALY gained by the exercise programme relative to best care cost €311 (95% CI, €143–€394). The cost effectiveness acceptability curves showed a 90% probability that the addition of the walking programme is the best strategy if the ceiling of inversion is €350/QALY.</p> <p>Conclusion</p> <p>The invitation strategy and exercise programme resulted in a high rate of participation and is a feasible and cost-effective addition to best care. The programme is a cost-effective resource for helping patients to increase their physical activity, according to the recommendations of general practitioners. Moreover, the present study could help decision makers enhance the preventive role of primary care and optimize health care resources.</p> <p>Trial Registration</p> <p>[ISRCTN98931797]</p

Non-oxidative methane conversion in microwave-assisted structured reactors

The main problem to be addressed in the valorization of methane under non-oxidative conditions (MNOC) is to reduce or even avoid coke formation. In this work we report the use of microwave-assisted heating for MNOC. We have developed a system able to heat-up a Mo-ZSM5 catalyst coated on silicon carbide monolith that could operate stable for at least 19¿h at reaction conditions, 700°C. We demonstrate that under MW-heating the selectivity shifts to C2s and benzene. In contrast, the operation under conventional heating (CH) produces more coke and polyaromatics. The selective microwave heating has two effects in this reaction: i) during the activation of the catalyst the formation of the active catalytic species of Mo2C inside the microporous support is different affecting the selectivity and product distribution; ii) a gas-solid temperature gradient is established that prevents the formation of coke from PAHs in the gas phase. The MNOC process under controlled MW heating at high space velocity (3000¿mL/gcat·h) gives a hydrocarbon yield of around 6% with a very low deactivation rate. These results open up new possibilities for process intensification using alternative sources of energy, as is the case of microwaves, for heating structured catalytic reactors

Atypical presentation and percutaneous repair of ascending aortic pseudoaneurysm: a case report

Pseudoaneurisma aòrtic; Tancament percutani; SíncopePseudoaneurisma aórtico; Cierre percutáneo; SíncopeAortic pseudoaneurysm; Percutaneous closure; SyncopeBackground Ascending aortic pseudoaneurysms (AAPs) are an unusual complication of cardiac or aortic surgery and are associated with a high risk of complications and mortality. Guidelines recommend surgical repair. There is few data concerning percutaneous occlusion of AAP. We present a case of syncope due to vascular and heart chamber compression by a large post-surgical AAP that was filled through a focal leak. Ascending aortic pseudoaneurysm was successfully occluded percutaneously. Case summary A 66-year-old man with a mechanical aortic prosthesis and a Dacron tube in the ascending aorta presented with syncope due to compression of the right atrium and superior vena cava by a large peritube collection. A computed tomography angiography (CTA) showed a large AAP that was filled through a small focal dehiscence of the tube proximal suture. Patient was dismissed for surgery due to high surgical risk. Then, AAP was successfully occluded percutaneously via a 6-French radial access and local anaesthesia. Discussion In patients with syncope and previous cardiac surgery, aortic complications should be ruled out. Although transthoracic echocardiography may be useful, CTA is the recommended diagnostic test for ruling out post-surgical AAP and allows the characterization of the number, localization, and size of the leaks. In selected patients with high surgical risk and favourable anatomic characteristics, a percutaneous closure could be indicated

Significado de la anemia en las diferentes etapas de la vida

Overview: Anemia is very common in primary care consultations and pediatrics, and IDA is the cause of 50% of all cases of anemia. Methodology: Literature review and documentary descriptive analysis of the pathogenesis of iron-deficiency anemia, the basic diagnostic tests to study IDA and the significance of such using a specific time period in the documentary search and inclusion criteria that takes into account factors that are analyzed in the study: Ideas about the metabolism of iron. Ideas about hematopoiesis. Laboratory diagnosis and classification of anemia. Clinical features of iron deficiency anemia. Causes of iron deficiency. Results and conclusion: The staged documentary study covers the publications on the pathogenesis of iron deficiency anemia, the basic diagnostic tests to study the IDA and the significance of such, and it shows how important this data is for professional nursing in the area of primary care and pediatrics, to identify it and act accordingly.Resumen: La anemia presenta una elevada prevalencia en las consultas de atención primaria y pediatría, y la ADH representa el 50% de todos los casos de anemia. Metodología: Revisión bibliográfica y análisis descriptivo documental sobre etiopatogenia de la anemia ferropénica, las pruebas diagnósticas básicas para el estudio de la ADH  y su significado, utilizando una temporalidad determinada en la búsqueda documental y criterios de inclusión atendiendo a las dimensiones que se analizan en el estudio: Nociones acerca del metabolismo del hierro. Nociones acerca de la hematopoyesis. Diagnóstico por el laboratorio y clasificación de las anemias. Clínica de la anemia ferropénica. Causas de la deficiencia de hierro. Resultados y conclusión: EL estudio documental efectuado nos presenta la existencia de publicaciones con contenidos sobre etiopatogenia de la anemia ferropénica, las pruebas diagnósticas básicas para el estudio de la ADH  y su significado, evidenciando la importancia de este contenido para el profesional de enfermería en el área de la atención primaria y pediatría

Divergent modulation of nociception by glutamatergic and GABAergic neuronal subpopulations in the periaqueductal gray

The ventrolateral periaqueductal gray (vlPAG) constitutes a major descending pain modulatory system and is a crucial site for opioid-induced analgesia. A number of previous studies have demonstrated that glutamate and GABA play critical opposing roles in nociceptive processing in the vlPAG. It has been suggested that glutamatergic neurotransmission exerts antinociceptive effects, whereas GABAergic neurotransmission exert pronociceptive effects on pain transmission, through descending pathways. The inability to exclusively manipulate subpopulations of neurons in the PAG has prevented direct testing of this hypothesis. Here, we demonstrate the different contributions of genetically defined glutamatergic and GABAergic vlPAG neurons in nociceptive processing by employing cell type-specific chemogenetic approaches in mice. Global chemogenetic manipulation of vlPAG neuronal activity suggests that vlPAG neural circuits exert tonic suppression of nociception, consistent with previous pharmacological and electrophysiological studies. However, selective modulation of GABAergic or glutamatergic neurons demonstrates an inverse regulation of nociceptive behaviors by these cell populations. Selective chemogenetic activation of glutamatergic neurons, or inhibition of GABAergic neurons, in vlPAG suppresses nociception. In contrast, inhibition of glutamatergic neurons, or activation of GABAergic neurons, in vlPAG facilitates nociception. Our findings provide direct experimental support for a model in which excitatory and inhibitory neurons in the PAG bidirectionally modulate nociception