Huge Avenues of Opportunities (With Some Potholes) Opened by the Very Small Things

In its incessant exploration of the cosmos into the cosmos, crossing the dimensionality barrier, science is living a unique moment with an unstoppable knowledge growth ranging from the subtle details of the immensity to the vastness of the very small. In the last aspect, progress is now incredible extremely rapid, and today, shape the matter at nanoscale to prepare engineered low dimensional systems (thin films, elongated nanostructures and nanocrystals and quantum dots) is an everyday reality common throughout the world. Nanoscopic objects with an increasing (and sometimes funny) variety of sizes and forms, including ..

Estudio del mecanismo de magnetización en nanoelipsoides de Fe con microestructuras diseñadas, bioinspiradas en la bacteria magnetotáctica

En este trabajo se estudia la preparación de nanoelipsoides magnéticos mediante la reducción con hidrógeno de nanoarquitecturas alargadas compuestas de nanocristales de hematites altamente orientados. En particular, se estudia el efecto del tiempo de reducción en las propiedades microestructurales y magnéticas de los nanoelipsoides prestando especial atención al estudio de las fuentes de anisotropía magnética presentes en el sistema y el posible mecanismo de inversión de la magnetización. In this work, the preparation route of magnetic nanoellipsoids by the hydrogen reduction of elongated nanoarchitectures composed by highly oriented hematite nanocrystals is revised. In particular, the effect of the reduction time on the microstructural and magnetic properties of the nanoellipsoids are studied with special attention to the different magnetic sources and the possible magnetization reversal mechanism

Exploring the potential of plant-derived natural products beyond functional food: Applications in nanomedicine

The use of plant products as nutritional food and therapeutic agents is immemorial and intimately linked to the human life since its origin. Also, the tanning action of plant extracts has been hugely exploited to transform animal skins into leather from ancient times to present. However, the exploitation of the potential applications of the plant biomolecules in some of the modern technologies is rather now emerging. In fact, the power antioxidant, reducing and biological activities of the plant metabolites, together their chelating and their biodegradable properties, make the plant-derived natural products unique raw materials to design new sustainable approaches to prepare promising hybrid formulations and composites at the nanometer scale for innovative diagnostic and therapeutic procedures and nanotechnology applications. In the present contribution, some recent advances in this topic are briefly discussed

Formación de partículas nanométricas en soluciones sobresaturadas

El estudio de los procesos asociados a la precipitación química en soluciones sobresaturadas es crucial para entender los mecanismos de algunos procesos naturales, como la biomineralización de estructuras biológicamente funcionales y la formación de rocas sedimentarias químicas. Por otra parte, este fenómeno puede emplearse en el laboratorio para sintetizar eficaz y versátilmente nuevos materiales de interés fundamental y práctico. En este trabajo se presenta una revisión de los fundamentos del fenómeno de la cristalización en soluciones sobresaturadas considerando su aplicación en la producción de nanopartículas uniformes con características controlables

Influence of the oxygen partial pressure on the growth and optical properties of RF-sputtered anatase TiO2 thin films

Titanium dioxide (TiO2) films with thicknesses around 300 nm were deposited on glass substrates by reactive radio frequency (RF) magnetron sputtering at constant RF sputtering power (200 W), high sputtering pressure and room temperature. The effects of the oxygen presence on the growth and properties of the films were investigated using mixtures of Ar and O2 with different O2/(Ar + O2) ratios (from 0.0 to 0.3) during the sample deposition. The crystalline properties and surface morphology were characterized using X-ray diffraction (XRD) and atomic force microscopy (AFM), respectively. The optical properties were studied by ultraviolet–visible–near infrared (UV–Vis–NIR) spectroscopy, and the refractive index and the thickness of the samples were obtained using the Swanepoel method. The obtained results indicate that all the TiO2 films grew with an anatase phase and with an improved crystallinity at O2/(Ar + O2) = 0.2. However, AFM studies show that the grain size and surface roughness decrease as the O2/(Ar + O2) ratio increases from 0.0 to 0.3. Moreover, a maximum refractive index was obtained for the sample prepared at O2/(Ar + O2) = 0.2

Fenómenos físicos de las nanopartículas de oro

El oro ha sido uno de los materiales más preciados por el hombre desde la antigüedad por sus excelentes propiedades, entre las que destaca su hermoso color y brillo, su maleabilidad y su estabilidad química. En las últimas décadas, el interés por este material se ha incrementado al encontrar que el oro en forma de nanopartículas presenta fenómenos físicos nuevos que incrementan su potencial tecnológico. En esta contribución presentamos una breve descripción de algunos de estos fenómenos, los cuales son objeto de estudio del cuerpo académico física de los sistemas de baja dimensionalidad y sus aplicaciones de la FCFM de la UANL

Synthesis and magnetic properties of iron nanoellipsoids bioinspired by magnetotactic bacteria

Ferromagnetic iron nanoellipsoids were prepared by the hydrogen reduction of ellipsoidal hematite nanoarchitectures. These magnetic nanoscale particles displayed a microstructure that showed clear similarities to the magnetosome chains of the magnetotactic bacteria. Specifically, such nanoellipsoids are formed by single-domain nanocrystals assembled into double chains sharing the same crystallographic orientation. In the present contribution, the magnetic properties of the Fe nanoellipsoids were explained considering the chain of spheres model of Jacobs and Bean, and thermal effects

Evolution over Time of Ventilatory Management and Outcome of Patients with Neurologic Disease∗

OBJECTIVES: To describe the changes in ventilator management over time in patients with neurologic disease at ICU admission and to estimate factors associated with 28-day hospital mortality. DESIGN: Secondary analysis of three prospective, observational, multicenter studies. SETTING: Cohort studies conducted in 2004, 2010, and 2016. PATIENTS: Adult patients who received mechanical ventilation for more than 12 hours. INTERVENTIONS: None. MEASUREMENTS AND MAIN RESULTS: Among the 20,929 patients enrolled, we included 4,152 (20%) mechanically ventilated patients due to different neurologic diseases. Hemorrhagic stroke and brain trauma were the most common pathologies associated with the need for mechanical ventilation. Although volume-cycled ventilation remained the preferred ventilation mode, there was a significant (p < 0.001) increment in the use of pressure support ventilation. The proportion of patients receiving a protective lung ventilation strategy was increased over time: 47% in 2004, 63% in 2010, and 65% in 2016 (p < 0.001), as well as the duration of protective ventilation strategies: 406 days per 1,000 mechanical ventilation days in 2004, 523 days per 1,000 mechanical ventilation days in 2010, and 585 days per 1,000 mechanical ventilation days in 2016 (p < 0.001). There were no differences in the length of stay in the ICU, mortality in the ICU, and mortality in hospital from 2004 to 2016. Independent risk factors for 28-day mortality were age greater than 75 years, Simplified Acute Physiology Score II greater than 50, the occurrence of organ dysfunction within first 48 hours after brain injury, and specific neurologic diseases such as hemorrhagic stroke, ischemic stroke, and brain trauma. CONCLUSIONS: More lung-protective ventilatory strategies have been implemented over years in neurologic patients with no effect on pulmonary complications or on survival. We found several prognostic factors on mortality such as advanced age, the severity of the disease, organ dysfunctions, and the etiology of neurologic disease