Graphene Based Sensors for Air Quality Monitoring - Preliminary Development Evaluation

Indoor air pollution can induce adverse health effects on building occupants and pose a significant role in health worldwide. To avoid such effects, it is extremely important to monitor and control common indoor pollutants such as CO2, VOCs and relative humidity. Therefore, this work focuses on recent advances in the field of graphene-based gas sensors, emphasizing the use of modified graphene that broadly expands the range of nanomaterials sensors. Graphene films were grown on copper by chemical vapor deposition (CVD) and transferred to arbitrary substrates. After synthesis, the samples were functionalized with Al2O3 by ALD and characterized by a large set of experimental techniques such as XPS, Raman and SEM. The results demonstrated that graphene was successfully synthesized and transferred to SiO2, glass and polymer. As a proof-of-concept, ALD of Al2O3 was performed on the graphene surface to produce a graphene/metal oxide nanostructure towards the development of nanocomposites for gas sensing. From this perspective, a laboratory prototype device based in measuring the electrical properties of the graphene sample as a function of the gas absorption is under development

Synthesis and Structure-Activity Relationship Studies of Dioxane- and Oxathiane-Based Analogs of (–)-Zampanolide

We have prepared a series of analogs of the complex marine macrolide (–)-zampanolide, which incorporate a dioxane-, oxathiane-, or oxathiane-dioxide ring in place of the natural tetrahydropyran moiety and we have determined their microtubule-binding affinity and antiproliferative activity against human cancer cells. The synthesis of these analogs was based on a convergent strategy with a HWE-based macrocyclization and a stereoselective aza-aldol reaction as key steps. The microtubule-binding affinity and cellular potency of the dioxane- and oxathiane-based analogs with a natural (Z,E)-sorbamide-based side chain were essentially indistinguishable from those of natural (–)-zampanolide; changing the configuration of the sorbamide unit from Z,E to E,E resulted in a slight loss in activity. In contrast, the presence of an oxathiane-dioxide ring caused a steep decrease in microtubule-binding and a significant loss in growth inhibitory activity. In addition, a substantial loss in potency was observed against a multidrug-resistant, P-glycoprotein-overexpressing cell line, while no such effect was found for the dioxane- or oxathiane-based analogs. A high-resolution X-ray crystal structure of the complex between beta-tubulin and dioxane-zampanolide was obtained, which showed that this compound, like natural (–)-zampanolide, induces helical structuring of the M-loop

Two step mechanochemical synthesis of Nb doped MgO rock salt nanoparticles and its application for hydrogen storage in MgH2

In the present study, we demonstrate two mechanochemical approaches suitable for the bulk scale synthesis of catalytically active Nb doped MgO rock salt nanoparticles. In the first method, Nb2O5 initially was reduced to NbO2 by MgH2 and then transformed to MgxNbyOx+y. In the second method, MgO and Nb2O5 were initially combined to make MgNb2O6 and then converted to MgxNbyOx+y. The DSC-TG and Sievert's volumetric analysis suggest that the end product, MgxNbyOx+y, is catalytically more active in comparison to all other oxide phases involved in the reaction, such as Nb2O5, NbO2 and MgNb2O6. (C) 2015 Hydrogen Energy Publications LLC. Published by Elsevier Ltd. All rights reserved

Contemporary use of cefazolin for MSSA infective endocarditis: analysis of a national prospective cohort

Objectives: This study aimed to assess the real use of cefazolin for methicillin-susceptible Staphylococcus aureus (MSSA) infective endocarditis (IE) in the Spanish National Endocarditis Database (GAMES) and to compare it with antistaphylococcal penicillin (ASP). Methods: Prospective cohort study with retrospective analysis of a cohort of MSSA IE treated with cloxacillin and/or cefazolin. Outcomes assessed were relapse; intra-hospital, overall, and endocarditis-related mortality; and adverse events. Risk of renal toxicity with each treatment was evaluated separately. Results: We included 631 IE episodes caused by MSSA treated with cloxacillin and/or cefazolin. Antibiotic treatment was cloxacillin, cefazolin, or both in 537 (85%), 57 (9%), and 37 (6%) episodes, respectively. Patients treated with cefazolin had significantly higher rates of comorbidities (median Charlson Index 7, P <0.01) and previous renal failure (57.9%, P <0.01). Patients treated with cloxacillin presented higher rates of septic shock (25%, P = 0.033) and new-onset or worsening renal failure (47.3%, P = 0.024) with significantly higher rates of in-hospital mortality (38.5%, P = 0.017). One-year IE-related mortality and rate of relapses were similar between treatment groups. None of the treatments were identified as risk or protective factors. Conclusion: Our results suggest that cefazolin is a valuable option for the treatment of MSSA IE, without differences in 1-year mortality or relapses compared with cloxacillin, and might be considered equally effective