Lipid-modulated assembly of magnetized iron-filled carbon nanotubes in millimeter-scale structures

Biomolecule-functionalized carbon nanotubes (CNTs) combine the molecular recognition properties of biomaterials with the electrical properties of nanoscale solid state transducers. Application of this hybrid material in bioelectronic devices requires the development of methods for the reproducible self-assembly of CNTs into higher-order structures in an aqueous environment. To this end, we have studied pattern formation of lipid-coated Fe-filled CNTs, with lengths in the 1–5 µm range, by controlled evaporation of aqueous CNT-lipid suspensions. Novel diffusion limited aggregation structures composed of end-to-end oriented nanotubes were observed by optical and atomic force microscopy. Significantly, the lateral dimension of assemblies of magnetized Fe-filled CNTs was in the millimeter range. Control experiments in the absence of lipids and without magnetization indicated that the formation of these long linear nanotube patterns is driven by a subtle interplay between radial flow forces in the evaporating droplet, lipid-modulated van der Waals forces, and magnetic dipole–dipole interactions. Keywords

Nomenclature of sp2 carbon nanoforms

Carbon’s versatile bonding has resulted in the discovery of a bewildering variety of nanoforms which urgently need a systematic and standard nomenclature [1]. Besides fullerenes, nanotubes and graphene, research teams around the globe now produce a plethora of carbon-based nanoforms such as ‘bamboo’ tubes, ‘herringbone’ and ‘bell’ structures. Each discovery duly gains a new, sometimes whimsical, name, often with its discoverer unaware that the same nanoform has already been reported several times but with different names (for example the nanoform in Fig. 1h is in different publications referred to as ‘bamboo’ [2], ‘herringbone-bamboo’ [3], ‘stacked-cups’ [4] and ‘stacked-cones’ [5]). In addition, a single name is often used to refer to completely different carbon nanoforms (for example, the ‘bamboo’ structure in [2] is notably different from ‘bamboo’ in [6]). The result is a confusing overabundance of names which makes literature searches and an objective comparison of results extremely difficult, if not impossible

3D Electrospinning of Al2O3/ZrO2 fibrous aerogels for multipurpose thermal insulation

Ceramic aerogels are excellent ultralight-weight thermal insulators yet impractical due to their tendency towards structural degradation at elevated temperatures, under mechanical disturbances, or in humid environments. Here, we present flexible and durable alumina/zirconia fibrous aerogels (AZFA) fabricated using 3D sol–gel electrospinning — a technique enabling in situ formation of 3D fiber assemblies with significantly reduced time consumption and low processing cost compared to most existing methods. Our AZFAs exhibit ultralow density (> 3.4 mg cm−3), low thermal conductivity (> 21.6 mW m−1 K−1), excellent fire resistance, while remaining mechanically elastic and flexible at 1300 °C, and thermally stable at 1500 °C. We investigate the underlying structure-thermal conductivity relationships, demonstrating that the macroscopic fiber arrangement dictates the solid-phase thermal conduction, and the mesopores in the fiber effectively trap air thereby decreasing the gas conduction. We show experimentally and theoretically that directional heat transport, i.e., anisotropic thermal conductivity, can be achieved through compressing the fiber network. We further solve the moisture sensitivity problem of common fibrous aerogels through fluorination coating. The resulting material possesses excellent hydrophobicity and self-cleaning properties, which can provide reliable thermal insulation under various conditions, including but not limited to high-temperature conditions in vehicles and aircraft, humid conditions in buildings, and underwater environments for oil pipelines. Graphical Abstract: [Figure not available: see fulltext.

Claves para la gestión de un centro de investigación científica en un contexto en el que se percibe saturación de responsabilidades y exigencias

Incluye bibliografía y anexosVencimiento de confidencialidad: 19/08/2018.El presente informe da cuenta de un proceso de asesoría organizacional, integrando un estudio diagnóstico y un plan de mejora, para una organización del área pública orientada a la investigación científica con funciones de formación. La demanda identificada fue la percepción de sobrecarga de responsabilidades y tareas en los responsables de áreas científicas. Para atender dicha demanda, se buscaron estrategias en conjunto con la institución, para lograr un escenario con un mejor clima organizacional y favorecer la eficacia institucional. De esta forma. se desarrolló un plan de mejora cuyo objetivo es aumentar la satisfacción de los responsables de áreas científicas, ligada a la eficacia del apoyo logístico brindado por la institución. Al finalizar el trabajo, se extrajeron cinco claves para la gestión del centro en cuestión que presentan un aporte a la comunidad científica, ya que pueden servir de antecedentes para otros estudios

Hierarchical porosity design enables highly recyclable and efficient Au/TiO2 composite fibers for photodegradation of organic pollutants

Titanium dioxide (TiO2) nanomaterials are ideal for photocatalytic degradation of organic pollutants but remain infeasible for industrial and municipal wastewater treatment because they cannot simultaneously satisfy two essential criteria for practical application, i.e., high performance and good recyclability. Here, we design and create hierarchically porous TiO2 fibers by dual-polymer templating sol–gel electrospinning combined with precise control over crystallization. The produced fibers own unique interconnected macropores throughout the fiber body that enable significantly enhanced light absorption and unlimited mass transport, making them ideal hosts for anchoring plasmonic nanoparticles (NPs). The Au NP-coupled TiO2 fibers have photocatalytic efficiencies up to 6.6 times higher than plain TiO2 fibers, showing comparable ability as commercial P25 nanopowder in photodegrading methyl blue (MB) and achieving complete decomposition of methyl orange (MO) in 90 min while P25 degrades only 66% MO. Unlike P25 or anatase TiO2 nanopowders that non-reversibly disperse/aggregate in water, our composite fibers can be recollected through natural sedimentation, and their superior performance remains for at least six cycles. This work offers a practical and feasible design for high-performance recyclable photocatalysts for industrial-scale water treatment

Frecuencia de los trastornos de adicción conductual encontrados en pacientes atendidos en el Hospital Hermilio Valdizán del 2009 al 2012

Publicación a texto completo no autorizada por el autorDetermina la frecuencia de los trastornos de adicción conductual encontrados en pacientes atendidos en el Hospital Hermilio Valdizan del 2009 al 2012. El estudio es de tipo descriptivo y transversal. La muestra es en base a las historias de pacientes que contienen algún diagnóstico de adicción conductual, la información fue ingresada a una base de datos y analizada por el paquete estadístico EpiInfo. Los resultados están basados en un total de 531 pacientes que representan el 0.24% de pacientes con alguna adicción conductual, las conductas adictivas encontradas fueron el uso problemático del internet, el juego patológico, el uso problemático del videojuego, adicción a la pornografía, adicción al sexo y cleptomanía. Se concluye que las conductas adictivas más tratadas son el uso problemático del internet y el juego patológico; la población más afectada en general es la de los adolescentes y adultos jóvenes, con características socio ocupacionales variadas, en la mayoría estudiantes.Tesi

Electrospinning nonspinnable sols to ceramic fibers and springs

Electrospinning has been applied to produce ceramic fibers using sol gel-based spinning solutions consisting of ceramic precursors, a solvent, and a polymer to control the viscosity of the solution. However, the addition of polymers to the spinning solution makes the process more complex, increases the processing time, and results in porous mechanically weak ceramic fibers. Herein, we develop a coelectrospinning technique, where a nonspinnable sol (2, ZrO2, SiO2, and Al2O3. The polycrystalline TiO2 fibers possess excellent flexibility and a high Young's modulus reaching 54.3 MPa, solving the extreme brittleness problem of the previously reported TiO2 fibers. The single-component ZrO2 fibers exhibit a Young's modulus and toughness of 130.5 MPa and 11.9 KJ/m3, respectively, significantly superior to the counterparts prepared by conventional sol-gel electrospinning. We also report the creation of ceramic fibers in micro- and nanospring morphologies and examine the formation mechanisms using thermomechanical simulations. The fiber assemblies constructed by the helical fibers exhibit a density-normalized toughness of 3.5-5 times that of the straight fibers due to improved fracture strain. This work expands the selection of the electrospinning solution and enables the development of ceramic fibers with more attractive properties

Identification of Electron Donor States in N-doped Carbon Nanotubes

Nitrogen doped carbon nanotubes have been synthesized using pyrolysis and characterized by Scanning Tunneling Spectroscopy and transmission electron microscopy. The doped nanotubes are all metallic and exhibit strong electron donor states near the Fermi level. Using tight-binding and ab initio calculations, we observe that pyridine-like N structures are responsible for the metallic behavior and the prominent features near the Fermi level. These electron rich structures are the first example of n-type nanotubes, which could pave the way to real molecular hetero-junction devices.Comment: 5 pages, 4 figures, revtex, submitted to PR

Presencia de aceite de palma en los productos alimenticios: Percepción del consumidor

[ES] El objetivo de este trabajo fue determinar la presencia del aceite de palma en los productos alimenticios que se encuentran a la venta, así como estudiar y comparar la opinión de los consumidores en relación a este tipo de aceite en España (país importador) y Perú (país productor). Para ello, se analizaron las noticias recientes en ambos países que podrían influir en la percepción de los consumidores. Se llevó a cabo un estudio del etiquetado de productos alimenticios y se realizó una encuesta a consumidores en España y en Perú. Los resultados mostraron diferencias en las noticias que se difundieron en ambos países, respecto a la importancia del contenido en grasas saturadas del aceite de palma. Se encontró aceite de palma en un gran número de productos y en una gama muy variada de alimentos, destacando el sector de bollería. Los porcentajes de grasa saturada fueron muy variables dentro de un mismo tipo de productos. Los consumidores españoles mostraron un mayor interés por el etiquetado y la información relativa a propiedades nutricionales, especialmente, en lo relativo a valor energético, grasas saturadas y azúcar, mientras que los peruanos se fijaban más en el valor energético, contenido en proteínas, vitaminas y minerales. En España el aceite de palma fue el que consideraron de peor calidad y con un claro efecto negativo para la salud y el medio ambiente. En Perú el aceite de palma no fue percibido por la mayoría como un aceite de mala calidad y no fue asociado por la mayoría de los encuestados a efectos negativos sobre la salud, aunque sí consideraron los problemas medioambientales que puede conllevar su producción.[EN] The objective of this work was to determine the presence of palm oil in the food products that are on sale, as well as to study and compare the opinion of consumers regarding this type of oil in Spain (importing country) and Peru (Producing country). To do this, we analyzed the recent news in both countries that could influence the perception of consumers. A study of the labeling of foodstuffs was carried out and a survey was realized to consumers in Spain and Peru. The results showed differences in the news that spread in both countries, regarding the importance of the saturated fat content of palm oil. Palm oil was found in a large number of products and in a very varied range of foods, especially the bakery sector. The percentages of saturated fat were very variable within the same type of products. Spanish consumers showed a greater interest in labeling and information regarding nutritional properties, especially in terms of energy value, saturated fats and sugar, while Peruvians focused more on the energy value, contained in proteins, vitamins and minerals. Minerals. In Spain, palm oil was considered the worst quality and with a clear negative effect on health and the environment. In Peru palm oil was not perceived by most as a poor quality oil and was not associated by the majority of the respondents with negative health effects, although theyGuadalupe Chuqui, GA. (2017). Presencia de aceite de palma en los productos alimenticios: Percepción del consumidor. http://hdl.handle.net/10251/87861.TFG