579 research outputs found
Functional SWNT Nanohybrids – Associating SWNTs with Water Soluble Enzyme Model Systems
No full textWe succeeded in integrating single-wall carbon nanotubes (SWNTs), several water-soluble pyrene derivatives (pyrene-), which bear negatively charged ionic headgroups, and a series of water-soluble metalloporphyrins (MP8+) into functional nanohybrids through a combination of associative van der Waals and electrostatic interactions
Sulfur-doped graphene/transition metal dichalcogenide heterostructured hybrids with electrocatalytic activity toward the hydrogen evolution reaction
No full textA facile route for the preparation of molybdenum disulfide (MoS2) and tungsten disulfide (WS2), uniformly deposited onto sulfur-doped graphene (SG), is reported. The realization of the SG/MoS2 and SG/WS2 heterostructured hybrids was accomplished by employing microwave irradiation for the thermal decomposition of ammonium tetrathiomolybdate and tetrathiotungstate, respectively, in the presence of SG. Two different weight ratios between SG and the inorganic species were used, namely 3:1 and 1:1, yielding SG/MoS2 (3:1), SG/MoS2 (1:1), SG/WS2 (3:1) and SG/WS2 (1:1). SG and all newly developed hybrid materials were characterized by ATR-IR and Raman spectroscopy, TGA, HR-TEM and EELS. The electrocatalytic activity of the SG/MoS2 and SG/WS2 heterostructured hybrids was examined against the hydrogen evolution reaction (HER) and it was found that the presence of SG not only significantly improved the catalytic activity of MoS2 and WS2 but also made it comparable to that of commercial Pt/C. Specifically, hybrids containing higher amounts of SG, namely SG/MoS2 (3:1) and SG/WS2 (3:1), exhibited extremely low onset overpotentials of 26 and 140 mV vs. RHE, respectively. The latter results highlighted the beneficial role of SG as a substrate for immobilizing MoS2 and WS2 and stressed its significance for achieving optimum electrocatalytic performance toward the HER. Finally, examination of the Tafel slopes as extracted from the electrocatalytic polarization curves, manifested the adsorption of hydrogen as the rate-limiting step for SG/MoS2 (3:1), while for SG/WS2 (3:1) the electrochemical desorption of adsorbed hydrogen atoms to generate hydrogen was revealed to be the rate-limiting step
Cell biology of carbon nanotubes
No full textCarbon nanotubes (CNTs) were first specifically identified and described in 1991.1 These nanoscale materials have since been widely used in a variety of fields due to their extraordinary properties, including high surface area, high mechanical strength, electronic properties, and excellent chemical and thermal stability. CNTs have also been developed and explored for a wide range of applications including in biomedicine, as biosensors, tissue engineering scaffolds, and drug delivery systems. The interaction between CNTs and mammalian cells was first observed by Pantarotto and co-workers in 2003. Chemically functionalized singlewalled CNTs were studied to report internalization by cells. Since then, more experimental techniques, materials, and cell types have been studied to identify the interaction between CNTs and cells in vitro. A variety of investigations are currently underway to study the interaction between biological systems and CNTs
Prometeo de Nikos Kazantzakis
No full textIn this essay about the dramatic trilogy Prometheus by Nikos Kazantzakis, it is analysed the recreation of myth as an esthetic resource allowing the author to show an existencialist conception of life. For that purpose a dialogue is established with the Aeschylos's tragedy who is the first poet to resort to this myth in a dramatic play.Then we analysed the reappropiation of myth carried out by Kazantzakis on the basis of an individual proposal, that describes an existencialist vision of man and life
Cell biology of carbon nanotubes
No full textCarbon nanotubes (CNTs) were first specifically identified and described in 1991.1 These nanoscale materials have since been widely used in a variety of fields due to their extraordinary properties, including high surface area, high mechanical strength, electronic properties, and excellent chemical and thermal stability. CNTs have also been developed and explored for a wide range of applications including in biomedicine, as biosensors, tissue engineering scaffolds, and drug delivery systems. The interaction between CNTs and mammalian cells was first observed by Pantarotto and co-workers in 2003. Chemically functionalized singlewalled CNTs were studied to report internalization by cells. Since then, more experimental techniques, materials, and cell types have been studied to identify the interaction between CNTs and cells in vitro. A variety of investigations are currently underway to study the interaction between biological systems and CNTs
Paramythia Tou Aisopou, Pemptos Tomos
No full textThis is the fifth of six volumes in a series that I found in Greek Video's catalogue. The first two volumes are under 1978/97, while the third and fourth are under 1986/96. Three stories: The Monkey and the Fox, BW, and The Lobster and the Fox. Nikos Neiros illustrates the first two stories and Michales Benetoulias the last. The animals' feats in competing for kingship in the first fable offer perhaps the best illustrations in this series. Many wolves attack the flock in the second fable. This volume returns to the format of the first two, with a small picture and a promythium on the title-page of each story. The monkey king, the fox, and other animals are pictured by Benetoulias on the cover. The back cover of all six volumes is the same.This is a hardbound book (hard cover)Language note: Modern GreekThird editionNestoras Chouno
Book review: Nikos Miltsios / Melina Tamiolaki (eds.): Polybius and His Legacy
No full textThis is the author accepted manuscript. The final version is freely available from the publisher via the link in this recordRezension von: Nikos Miltsios / Melina Tamiolaki (eds.): Polybius and His Legacy, Berlin: de Gruyter 201
Nikos Kazantzakis, un pensador de nuestro tiempo
No full textProfessor Stassinakis, Presiden! of the Société Internationale des Amis de Nikos Kazantzakis presents a summary of diverse aspects of the Greek writer's personality and work. Stassinakis' study has three sections: a) Introduction and analisys of Kazantzakis' thought b) His active presence in society e) The man of the approach between the peoples and the synthesis. -Befare the exposition of the three themes, the author numbers the writer' s work, which is only partially known in our language. In the summarizing of Kazantzakis thought, the author highlights his search for freedom, his veneration for Nature and the primacy of the spirit in his work.
Besides highlighting the Cretan root of his personality and creation, the author studies the effort for the approach between the peoples, by
means of his voyages, his translations, his writings and his different activities.
The article brings a global vision about the Creten writer and his work
Nikos Kazantzakis: La espera muda
No full textUsing two key concepts in existentialist philosophy, "situation" and "limit situation", this article establishes a relation of solidarity between the thought of Nikos Kazantzakis and Karl Jaspers. The dramatic work Comedy...tragedy in one act is analyzed from this existential concept, also establishing some considerations about Jean Paul Sartre's thought on a "theatre of situations". Kazantzakis' work is analyzed taking into consideration elements proper to drama seen from the point of view of the central motif which runs through it, salvation and the pursuit of transcendence. Lastly, the projections of this motif in the whole work of the author are touched upon, as well as the lucidity with which he anticipat es other authors and European tendencies of midtwentieth century.El siguiente artículo establece una relación solidaria entre el pensamiento de Nikos Kazantzakis y Karl Jaspers, a partir de dos conceptos claves para la filosofía existencialista: el de "situación" y "situación límite". Es a partir de esta concepción existencial que se analiza la pieza dramática Comedia...tragedia en un acto, estableciendo también algunas consideraciones con el pensamiento de Jean Paul Sartre en torno a un "Teatro de situaciones". La obra de Kazantzakis es analizada atendiendo a los elementos propios del drama a la luz del motivo central que la recorre, la salvación y búsqueda de trascendencia. Por último, se señalan las proyecciones de este motivo en la obra global del autor y la lucidez co
Molybdenum diselenide-manganese porphyrin bifunctional electrocatalyst for the hydrogen evolution reaction and selective hydrogen peroxide production
No full textElectrochemical reactions for hydrogen and hydrogen peroxide production are essential for energy conversion to diminish the energy crisis but still lack efficient electrocatalysts. Development of non-noble metal bifunctional electrocatalysts for the hydrogen evolution reaction and 2e– oxygen reduction reaction to ease reaction kinetics is a challenging task. Integration of single components by employing easy strategies provides a key step toward the realization of highly active electrocatalysts. In this vein, MoSe2 owns catalytic active sites and a high specific surface area but suffers from insufficient conductivity and high catalytic performance that noble metals provide. Herein, MoSe2 was used as a platform for the incorporation of manganese-metalated porphyrin (MnP). The developed hybrid, namely, MoSe2–MnP, obtained by the initial metal–ligand coordination and the subsequent grafting with MnP was fully characterized and electrochemically assessed. The bifunctional electrocatalyst lowered the overpotential toward hydrogen evolution, improved the reaction kinetics and charge transfer processes, and was extremely stable after 10,000 ongoing cycles. Simultaneously, rotating ring disk electrode analysis showed that oxygen reduction proceeds through the 2e– pathway for the selective production of hydrogen peroxide with a high yield of 97%. The new facile modification route can be applied in diverse transition metal dichalcogenides and will help the development of new advanced functional materials.R.A. acknowledges support from Spanish MICINN (PID2019-104739GB-100/AEI/10.13039/501100011033), the Government of Aragon (projects DGA E13-20R) and from EU H2020 “ESTEEM3” (grant number 823717) and Graphene Flagship (881603). The TEM studies were performed in the Laboratorio de Microscopias Avanzadas (LMA), Universidad de Zaragoza (Spain). R.A. acknowledges support from Spanish MICINN (PID2019-104739GB-100/AEI/10.13039/501100011033), the Government of Aragon (projects DGA E13-20R) and from EU H2020 “ESTEEM3” (grant number 823717) and Graphene Flagship (881603).Peer reviewe
- …
