Search results for "note"

Surface and interface effects on the current-voltage characteristic curves of multiwall carbon nanotube-Si hybrid junctions selectively probed throug…

2021

The possibility to increase the efficiency of photovoltaic (PV) cells based on hybrid carbon nanotube (CNT)–Si heterojunctions is related to the ability to control the chemical properties of the CNT–Si interface and of the CNT bundle layer. In spite of the encouraging performances of PV cells based on multiwall (MW) CNT, so far few efforts have been made in the study of this device compared to single wall (SW) CNT–Si interfaces. Here, surface and interface effects on the current–voltage characteristic curves of MW CNT–Si hybrid junctions are investigated through exposure to HF vapors and to 10 ppm-NO2 and compared to the effects detected in SW CNT–Si junctions. Quite similar results in term…

Heterogeneous Photocatalysis for Selective Formation of High-Value-Added Molecules: Some Chemical and Engineering Aspects

2018

This review deals with the parameters that influence heterogeneous photocatalysis (PC) for selective synthesis of high-value chemicals by itself or in combination with other technologies. In particular, the parameters related to the photocatalysts, such as crystallinity degree, type of polymorph, surface acid-base properties, exposure of particular crystalline facets, coupling of different semiconductors, position of the valence and conduction band edge, addition of doping agents, and those related to the reaction system, such as setup configuration and reactor geometry, type of solvent, type and amount of photocatalyst, affecting the selectivity toward specific products are described and d…

Nanomanipulaatioon ja elektronimikroskopiaan perustuva hiilinanoputkien käsittelymenetelmä

2008

A Computational Study of Adsorption of CO2, SO2, and H2CO on Free-Standing and Molybdenum-Supported CaO Films

2018

Oxide films play a significant role in a wide range of fields from catalysis to solar cell materials. CaO films are promising sorbents for many environmentally harmful molecules. Here, we report a systematic investigation of adsorption of CO2, SO2, and H2CO on bulk and Mo-supported CaO(100) films using density functional theory. Significant effects on adsorption energy, charge transfer to the molecules, and degree of the C–O bond activation were demonstrated on Mo-supported CaO films by changing the film thickness, composition, and the strength and direction of an applied external electric field. These findings are relevant for interpreting results from scanning tunneling microscopy of smal…

Organoterapia de la diabetes mellitus (1889-1923): la controversia de prioridades en torno al descubrimiento de la hormona antidiabética

2021

La introducción del tratamiento hormonal en la diabetes grave en 1922 representó un impacto clínico-social similar al de la antibioterapia. En octubre de 1923 la Asamblea del Instituto Karolinska decidió premiar con el Nobel de Fisiología o Medicina al canadiense Frederick Grant Banting y al escocés John James Rickard Macleod, investigadores de la Universidad de Toronto (UT), por “el descubrimiento de insulina un año antes”. Transcurridas pocas semanas, investigadores europeos y estadounidenses protestaron la decisión. La polémica permanece hasta la actualidad. En septiembre de 2005, la European Association for the Study of Diabetes (EASD) organizó el simposio internacional Who Discovered I…

Cationic and Anionic Impact on the Electronic Structure of Liquid Water

2017

Hydration shells around ions are crucial for many fundamental biological and chemical processes. Their local physicochemical properties are quite different from those of bulk water and hard to probe experimentally. We address this problem by combining soft X-ray spectroscopy using a liquid jet and molecular dynamics (MD) simulations together with ab initio electronic structure calculations to elucidate the water–ion interaction in a MgCl2 solution at the molecular level. Our results reveal that salt ions mainly affect the electronic properties of water molecules in close vicinity and that the oxygen K-edge X-ray emission spectrum of water molecules in the first solvation shell differs signi…

Biological Effects of New Hydraulic Materials on Human Periodontal Ligament Stem Cells.

2019

Background: The aim of this study was: to evaluate the biological properties of new hydraulic materials: Bio-C Repair and Bio-C Sealer. Methods: Periodontal ligament stem cells were exposed to several dilutions of Bio-C Repair and Bio-C Sealer. The ion release profile and pH were determined. Metabolic activity, cell migration and cell survival were assessed using the 3-(4, 5-dimethylthiazol-2-yl)-2, 5-diphenyltetrazolium bromide (MTT), wound-healing assays and Annexin assays, respectively. Cells were cultured in direct contact with the surface of each material. These were then analyzed via scanning electron microscopy (SEM) and energy dispersive X-ray (EDX). Statistical differences were ass…

Revisited Dual Luminescence of 2,2′-Dipyridylamine Hydrochloride in Solution and Physical Processes behind It

2018

Structural and Electrochemical Analysis of CIGS: Cr Crystalline Nanopowders and Thin Films Deposited onto ITO Substrates

2021

A new approach for the synthesis of nanopowders and thin films of CuInGaSe2 (CIGS) chalcopyrite material doped with different amounts of Cr is presented. The chalcopyrite material CuInxGa1 − xSe2 was doped using Cr to form a new doped chalcopyrite with the structure CuInxCryGa1 − x − ySe2, where x = 0.4 and y = 0.0, 0.1, 0.2, or 0.3. The electrical properties of CuInx CryGa1 − x − ySe2 are highly dependent on the Cr content and results show these materials as promising dopants for the fabrication thin film solar cells. The CIGS nano-precursor powder was initially synthesized via an autoclave method, and then converted into thin films over transparent substrates. Both crystalline precursor p…

Co-reductive fabrication of carbon nanodots with high quantum yield for bioimaging of bacteria

2018

A simple and straightforward synthetic approach for carbon nanodots (C-dots) is proposed. The strategy is based on a one-step hydrothermal chemical reduction with thiourea and urea, leading to high quantum yield C-dots. The obtained C-dots are well-dispersed with a uniform size and a graphite-like structure. A synergistic reduction mechanism was investigated using Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy. The findings show that using both thiourea and urea during the one-pot synthesis enhances the luminescence of the generated C-dots. Moreover, the prepared C-dots have a high distribution of functional groups on their surface. In this work, C-dots proved …