Editorial for the special issue on carbon based electronic devices

For more than 50 years, silicon has dominated the electronics industry [...]

Microwave characterization of polymer composite based on Biochar: A comparison of composite behaviour for Biochar and MWCNTs

In this work, Biochar is used as a filler in Epoxy resin for composite preparation. The electrical characteristics of composites are analyzed in function of different filler percentages. Results obtained are compared with composites based on multi-wall carbon nanotubes

Multiwalled carbon nanotube - Strength to polymer composite

Carbon nanotubes (CNTs), a rather fascinating material, are among the pillars of nanotechnology. CNTs exhibit unique electrical, mechanical, adsorption, and thermal properties with high aspect ratio, exceptional stiffness, excellent strength, and low density, which can be exploited in the manufacturing of revolutionary smart nano composite materials. The demand for lighter and stronger polymer composite material in various applications is increasing every day. Among all the possibilities to research and exploit the exceptional properties of CNTs in polymer composites we focused on the reinforcement of epoxy resin with different types of multiwalled carbon nano tubes (MWCNTs). We studied mechanical properties such as stress, strain, ultimate tensile strength, yield point, modulus and fracture toughness, and Young's modulus by plotting and calculating by means of the off-set method. The mechanical strength of epoxy composite is increased intensely with 1 and 3 wt.% of filler

Ceramide-induced BOK promotes mitochondrial fission in preeclampsia

Mitochondria are in a constant balance of fusing and dividing in response to cellular cues. Fusion creates healthy mitochondria, whereas fission results in removal of non-functional organelles. Changes in mitochondrial dynamics typify several human diseases. However, the contribution of mitochondrial dynamics to preeclampsia, a hypertensive disorder of pregnancy characterized by placental cell autophagy and death, remains unknown. Herein, we show that the mitochondrial dynamic balance in preeclamptic placentae is tilted toward fission (increased DRP1 expression/activation and decreased OPA1 expression). Increased phosphorylation of DRP1 (p-DRP1) in mitochondrial isolates from preeclamptic placentae and transmission electron microscopy corroborated augmented mitochondrial fragmentation in cytotrophoblast cells of PE placentae. Increased fission was accompanied by build-up of ceramides (CERs) in mitochondria from preeclamptic placentae relative to controls. Treatment of human choriocarcinoma JEG3 cells and primary isolated cytrophoblast cells with CER 16:0 enhanced mitochondrial fission. Loss- and gain-of-function experiments showed that Bcl-2 member BOK, whose expression is increased by CER, positively regulated p-DRP1/DRP1 and MFN2 expression, and localized mitochondrial fission events to the ER/MAM compartments. We also identified that the BH3 and transmembrane domains of BOK were vital for BOK regulation of fission. Moreover, we found that full-length PTEN-induced putative kinase 1 (PINK1) and Parkin, were elevated in mitochondria from PE placentae, implicating mitophagy as the process that degrades excess mitochondria fragments produced from CER/BOK-induced fission in preeclampsia. In summary, our study uncovered a novel CER/BOK-induced regulation of mitochondrial fission and its functional consequence for heightened trophoblast cell autophagy in preeclampsia

Pacientes atendidos en un centro toxicológico de venezuela

Objetivo Caracterizar los pacientes atendidos en un Centro Toxicológico de la Región Centro Occidental de Venezuela. Métodos Se realizó un estudio descriptivo y transversal. La población estuvo constituida por 1 938 pacientes registrados durante los años 2006 y 2007 en las planillas de recolección de datos del Centro. Resultados Del total de pacientes registrados en las planillas del Centro Toxicológico en el bienio 06-07,  57,4 % consultaron en el 2006. La edad media de los pacientes atendidos fue de 19 años en el 2006 y 20 años en el 2007, con atención tanto de niños como de adultos, siendo el sexo masculino el que mayormente consultó (55,4 %). La causa de consulta más frecuente en el lapso estudiado para ambos sexos fue emponzoñamientos, de los cuales más del 40 % fue por serpientes del género Bothrops, en hombres la segunda causa fue intoxicación por plaguicidas (20,6 %) y en mujeres intoxicación medicamentosa con un 26,6 %. El municipio del Estado Lara con mayor afluencia de pacientes fue Iribarren con 47,8 %, y durante los dos años se atendieron 95 pacientes (4,9 %) que provenían de Estados vecinos (Portuguesa y Yaracuy principalmente).  Conclusiones Se espera que con el presente estudio se implementen programas especiales de educación y atención para las patologías diagnosticadas con mayor frecuencia, así como los correctivos considerando los riesgos individuales y colectivos en las diferentes zonas geográficas del Estado Lara

Contabilidade ambiental em emergia do processamento de rocha calcária para uso agrícola.

Resumo: O presente estudo propõe uma contabilidade ambiental do processamento de calcário de rocha para uso agrícola, com aplicação da metodologia da síntese em emergia de um empreendimento atuante no referido setor, localizado no município de Arcos - MG. Na produção agrícola, o calcário é utilizado com a finalidade de corrigir o pH do solo e fornecer suplemento de cálcio e magnésio para as plantas. Os estudos de contabilidade ambiental via método da síntese em emergia de empreendimentos agrícolas têm utilizado apenas a transformidade da rocha calcária, sem consideração para etapas de processamento. Neste sentido, o presente estudo visa calcular a transformidade do Calcário Agrícola, que é a rocha calcária processada. A metodologia apresenta resultados sintéticos e de fácil entendimento que auxiliam na busca do desenvolvimento sustentável. As análises indicam que a emergia total do sistema é de 8,70E+21 sej/ano, resultando em uma transformidade de 2,81E+6 sej/J como co-produto e de 4,30E+6 sej/J como ?Split?. Em relação à transformidade da rocha calcária calculada por Odum (1996; 2000) o Calcário Agrícola representa um aumento de 2% no co-produto e 55% no ?Split?

Repurposing Face Masks after Use: From Wastes to Anode Materials for Na-Ion Batteries

Nowadays, face masks play an essential role in limiting coronavirus diffusion. However, their disposable nature represents a relevant environmental issue. In this work, we propose the utilization of two types of disposed (waste) face masks to prepare hard carbons (biochar) by pyrolytic conversion in mild conditions. Moreover, we evaluated the application of the produced hard carbons as anode materials in Na-ion batteries. Pristine face masks were firstly analyzed through infrared spectroscopy and thermogravimetric analysis. The pyrolysis of both mask types resulted in highly disordered carbons, as revealed by field-emission scanning electron microscopy and Raman spectroscopy, with a very low specific surface area. Anodes prepared with these carbons were tested in laboratory-scale Na-metal cells through electrochemical impedance spectroscopy, cyclic voltammetry and galvanostatic cycling, displaying an acceptable specific capacity along a wide range of current regimes, with a good coulombic efficiency (>98% over at least 750 cycles). As a proof of concept, the anodes were also used to assemble a Na-ion cell in combination with a Na3V2(PO4)(2)F-3 (NVPF) cathode and tested towards galvanostatic cycling, with an initial capacity of almost 120 mAhg(-1) (decreasing at about 47 mAhg(-1) after 50 cycles). Even though further optimization is required for a real application, the achieved electrochemical performances represent a preliminary confirmation of the possibility of repurposing disposable face masks into higher-value materials for Na-ion batteries

Mechanical properties of epoxy/multi-walled carbon nanotubes composites

In this paper, two types of multi-wall carbon nanotubes (MWCNTs) were dispersed into two different epoxy resins b high - shear mixing. Dispersion and homogenisation of nanofillers was analysed by Field Emission Scanning Electron Microscopy (FESEM). Microhardness of epoxy/MWCNTs nanocomposites, as well as of neat epoxy resins, is measure by Vickers method. The evolution of nanocomposites microhardness values were studied in function of curing time takin in account the influence of two different epoxy matrix and MWCNTs. Asymptotic values were analysed and compare with those of pure epoxy resin

Bi2O3/Nylon multilayered nanocomposite membrane for the photocatalytic inactivation of waterborne pathogens and degradation of mixed organic pollutants

Worldwide there is an increasing demand for clean water and sanitation systems and any different solutions are under evaluation, including advanced oxidation processes such as photocatalysis. This work describes the scalable synthesis process of an electrospun composite membrane made of Nylon and embedded α/β-Bi2O3 nanoparticles that can be activated by visible light instead of UV light typically used with other nanomaterials (e.g. TiO2). As a proof of concept, the efficacy of the α/β-Bi2O3 electrospun composite membrane in the visible light inactivation of pollutants and pathogens was demonstrated in a Continuous-flow Photocatalytic Membrane Reactor, highlighting the great potential of this advanced photocatalytic process for clean water and sanitation