Graphene Gold Nanoparticle Hybrid Based Near Infrared Photodetector

This paper presents novel and simplistic approach towards the development of graphene based near infrared (NIR) photodetectors. The developed device comprises of Au nanoparticles integrated within the channel of the back-gated graphene field effect transistors. The introduction of Au nanoparticles enhanced response of the device under IR illumination due improved NIR absorption. Further, dynamic response of the device under IR illumination is presented. This study will trigger the development of novel hybrid graphene device for graphene based photodetectors in IR regime

Tuning Electrical Conductivity of CNT-PDMS Nanocomposites for Flexible Electronic Applications

This paper presents a study into the electrical conductivity of multi-wall carbon nanotube-polydimethylsiloxane (MWNT-PDMS) nanocomposite and their dependence on the filler concentration. It is observed that the electrical conductivity of the composites can be tailored by altering the filler concentration. Accordingly, the nanocomposites with filler weight ratio ranging from 1% to 8% were prepared and tested. Finally, the significance of results presented here for flexible pressure sensors and stretchable interconnects for electronic skin applications have been discussed

Piezoelectric graphene field effect transistor pressure sensors for tactile sensing

This paper presents graphene field-effect transistor (GFET) based pressure sensors for tactile sensing. The sensing device comprises GFET connected with a piezoelectric metal-insulator-metal (MIM) capacitor in an extended gate configuration. The application of pressure on MIM generates a piezo-potential which modulates the channel current of GFET. The fabricated pressure sensor was tested over a range of 23.54–94.18 kPa, and it exhibits a sensitivity of 4.55 × 10−3 kPa−1. Further, the low voltage (∼100 mV) operation of the presented pressure sensors makes them ideal for wearable electronic applications

Garbage in, garbage out: how reliable training data improved a virtual screening approach against SARS-CoV-2 MPro

Introduction: The identification of chemical compounds that interfere with SARS-CoV-2 replication continues to be a priority in several academic and pharmaceutical laboratories. Computational tools and approaches have the power to integrate, process and analyze multiple data in a short time. However, these initiatives may yield unrealistic results if the applied models are not inferred from reliable data and the resulting predictions are not confirmed by experimental evidence.Methods: We undertook a drug discovery campaign against the essential major protease (MPro) from SARS-CoV-2, which relied on an in silico search strategy –performed in a large and diverse chemolibrary– complemented by experimental validation. The computational method comprises a recently reported ligand-based approach developed upon refinement/learning cycles, and structure-based approximations. Search models were applied to both retrospective (in silico) and prospective (experimentally confirmed) screening.Results: The first generation of ligand-based models were fed by data, which to a great extent, had not been published in peer-reviewed articles. The first screening campaign performed with 188 compounds (46 in silico hits and 100 analogues, and 40 unrelated compounds: flavonols and pyrazoles) yielded three hits against MPro (IC50 ≤ 25 μM): two analogues of in silico hits (one glycoside and one benzo-thiazol) and one flavonol. A second generation of ligand-based models was developed based on this negative information and newly published peer-reviewed data for MPro inhibitors. This led to 43 new hit candidates belonging to different chemical families. From 45 compounds (28 in silico hits and 17 related analogues) tested in the second screening campaign, eight inhibited MPro with IC50 = 0.12–20 μM and five of them also impaired the proliferation of SARS-CoV-2 in Vero cells (EC50 7–45 μM).Discussion: Our study provides an example of a virtuous loop between computational and experimental approaches applied to target-focused drug discovery against a major and global pathogen, reaffirming the well-known “garbage in, garbage out” machine learning principle

Infrared study of the adsorption of nitrogen dioxide, nitric oxide and nitrous oxide on hematite

An infrared spectroscopic study of the adsorption of NO2, NO, and N2O on \u3b1-Fe2O3 was carried out in order to identify chemisorbed species which could act as catalytic intermediates. Presorptions of pyridine and water were used in addition to usual pretreatments of the surface, in order to identify and discuss adsorption sites and mechanisms. Stable nitrate ions are formed on the surface, starting at beam temperature (b.t.) with NO and are predominant at 150 \ub0C with NO2. Between b.t. and 150 \ub0C, NO2 mainly chemisorbs as such or as its dimer N2O4. Depending on the pressure, NO chemisorbs at b.t. also as is or as NO- ions, as well as in the form of its dimer N2O2. N2O merely physisorbs on an "oxygen-rich" surface, but it strongly chemisorbs on an "evacuated" surface producing species which can be identified as N2O-. \ua9 1981

Infrared study of CO2 adsorption on haematite

This work has shown that CO2 molecules can interact at b.t. with high surface \u3b1-Fe2O3 obtained by thermal decomposition of goethite giving: a) physisorption, possibly via charge transfer mechanism between the carbon atom and the oxygen of a surface hydroxyl; b) formation of both monodentate and bidentate carbonate ions which can be easily decomposed by degassing even at b.t.. More severe conditions of contact allow the progressive formation of Fe2O2CO3 layers thermally stable up to 400\ub0C which can be identified through their characteristic IR absorptions. \ua9 1980

Infrared study of the reactivity of acetone and hexachloroacetone adsorbed on haematite

Infrared spectra of acetone adsorbed at beam temperature on \u3b1-Fe2O3 show that acetone can chemisorb on Lewis-acid sites and gives, at least partially, enolate anions; these, by aldolic condensation with molecules from the gas phase, produce a chemisorbed form of mesityl oxide. At 523 K acetate ions are formed. Two different forms of trichloroacetate ions are formed on the surface at beam temperature by the adsorption of hexachloroacetone and trichloroacetic acid. This behaviour indicates the presence of pairs of acid-base sites on the surface of haematite, and also shows that its surface hydroxy groups have a lower degree of nucleophilic character with respect to those of other oxides such as aluminas, SnO2 and alkaline-earth oxides