Direct Graphene Deposition via a Modified Laser-Assisted Method for Interdigitated Microflexible Supercapacitors.

The transcendence toward smarter technologies and the rapid expansion of the Internet of Things requires miniaturized energy storage systems, which may also be shape-conformable, such as microflexible supercapacitors. Their fabrication must be compatible with emerging manufacturing platforms with regard to scalability and sustainability. Here, we modify a laser-based method we recently developed for simultaneously synthesizing and transferring graphene onto a selected substrate.

Toxicological assessment of commercial monolayer tungsten disulfide nanomaterials aqueous suspensions using human A549 cells and the model fungus Saccharomyces cerevisiae.

The utilization of tungsten disulfide (WS) nanomaterials in distinct applications is raising due to their unique physico-chemical properties, such as low friction coefficient and high strength, which highlights the necessity to study their potential toxicological effects, due to the potential increase of environmental and human exposure. The aim of this work was to analyze commercially available aqueous dispersions of monolayer tungsten disulfide (2D WS) nanomaterials with distinct lateral size employing a portfolio of physico-chemical and toxicological evaluations. The structure and stoichiometry of monolayer tungsten disulfide (WS-ACS-M) and nano size monolayer tungsten disulfide (WS-ACS-N) was analyzed by Raman spectroscopy, whereas a more quantitative approach to study the nature of formed oxidized species was undertaken employing X-ray photoelectron spectroscopy.

Assessment of Physico-Chemical and Toxicological Properties of Commercial 2D Boron Nitride Nanopowder and Nanoplatelets.

Boron nitride (BN) nanomaterials have been increasingly explored for potential applications in chemistry and biology fields (e.g., biomedical, pharmaceutical, and energy industries) due to their unique physico-chemical properties.

Fate assessment of commercial 2D MoS aqueous dispersions at physicochemical and toxicological level.

The physicochemical properties and the toxicological potential of commercially available MoS nanoparticles with different lateral size and degradation stage were studied in the present research work. To achieve this, the structure and stoichiometry of fresh and old aqueous suspensions of micro-MoS and nano-MoS was analyzed by Raman, while x-ray photoelectron spectroscopy allowed to identify more quantitatively the nature of the formed oxidized species. A, the toxicological impact of the nanomaterials under analysis was studied using adenocarcinomic human alveolar basal epithelial cells (A549 cells) and the unicellular fungus S.

Optical Properties and Structure of As-Sb Chalcohalide Glasses by Raman Scattering and Density Functional Theory Calculations.

We report an investigation of the optical properties, structure, and vibrational modes of SbAsSI glasses (0 at. % < < 37 at. %).

Thermal dewetting tunes surface enhanced resonance Raman scattering (SERRS) performance.

Surface Enhanced Raman Spectroscopy (SERS) belongs to the techniques of ultra-sensitive chemical analysis and involves both identification and quantification of molecular species. Despite the fact that theoretically derived enhancement factors imply that even single molecules may be identified, which in some cases has indeed been experimentally observed, the application of this specific technique as an analytical tool is still an open field of research due to the need for reproducible, stable and simple to prepare SERS active substrates. The current work attempts to contribute to the already established knowledge on the substrates of metallic nanostructured films by a systematic study on the optimal conditions required for the detection of a specifically selected (model) material, the antitumor drug mitoxantrone (MTX).

Laser-induced transformation of graphitic materials to two-dimensional graphene-like structures at ambient conditions.

Laser processing of carbon compounds towards the formation of graphene-based structures gains ground in view of the practicality that lasers offer against other conventional graphene preparation methods. The current work explores the viability of low-cost lasers, operating at ambient conditions, for the transformation of various graphitic materials to structures with graphene-like atomic arrangements. Starting materials are at two opposing sides.

Factors Affecting the Power Conversion Efficiency in ZnO DSSCs: Nanowire vs. Nanoparticles.

A comparative assessment of nanowire versus nanoparticle-based ZnO dye-sensitized solar cells (DSSCs) is conducted to investigate the main parameters that affect device performance. Towards this aim, the influence of film morphology, dye adsorption, electron recombination and sensitizer pH on the power conversion efficiency (PCE) of the DSSCs is examined. Nanoparticle-based DSSCs with PCEs of up to 6.

The Essential Elements of a Risk Governance Framework for Current and Future Nanotechnologies.

Societies worldwide are investing considerable resources into the safe development and use of nanomaterials. Although each of these protective efforts is crucial for governing the risks of nanomaterials, they are insufficient in isolation. What is missing is a more integrative governance approach that goes beyond legislation.

X-Ray Crystallographic Analysis, EPR Studies, and Computational Calculations of a Cu(II) Tetramic Acid Complex.

In this work we present a structural and spectroscopic analysis of a copper(II) N-acetyl-5-arylidene tetramic acid by using both experimental and computational techniques. The crystal structure of the Cu(II) complex was determined by single crystal X-ray diffraction and shows that the copper ion lies on a centre of symmetry, with each ligand ion coordinated to two copper ions, forming a 2D sheet. Moreover, the EPR spectroscopic properties of the Cu(II) tetramic acid complex were also explored and discussed.

Facile, substrate-scale growth of mono- and few-layer homogeneous MoS2 films on Mo foils with enhanced catalytic activity as counter electrodes in DSSCs.

The growth of MoS2 films by sulfurization of Mo foils at atmospheric pressure is reported. The growth procedure provides, in a controlled way, mono- and few-layer thick MoS2 films with substrate-scale uniformity across square-centimeter area on commercial foils without any pre- or post-treatment. The prepared few-layer MoS2 films are investigated as counter electrodes for dye-sensitized solar cells (DSSCs) by assessing their ability to catalyse the reduction of I3(-) to I(-) in triiodide redox shuttles.

Lipid-like self-assembling peptide nanovesicles for drug delivery.

Amphiphilic self-assembling peptides are functional materials, which, depending on the amino acid sequence, the peptide length, and the physicochemical conditions, form a variety of nanostructures including nanovesicles, nanotubes, and nanovalves. We designed lipid-like peptides with an aspartic acid or lysine hydrophilic head and a hydrophobic tail composed of six alanines (i.e.

The influence of Au film thickness and annealing conditions on the VLS-assisted growth of ZnO nanostructures.

High temperature evaporation methods, such as the vapor-liquid-solid mechanism, have been exploited for the controlled growth of ZnO nanostructures on various substrates. While Au is the most frequently used catalyst for growing ZnO nanowires, its morphological features on the substrate, which determine the size and shape of the nanostructures grown, have not yet been methodically explored. In the current work, we investigated the details of the thermal dewetting of Au films into nanoparticles on Si substrates.

The glassy and supercooled state of elemental sulfur: vibrational modes, structure metastability, and polymer content.

We report a detailed investigation of vibrational modes, structure, and dynamics of elemental sulfur in the glassy and the supercooled state, using Raman scattering and ab initio calculations. Polarized Raman spectra are recorded--for sulfur quenched from 473 K--over a broad temperature range from 93 K to 273 K where the supercooled liquid crystallized. The temperature induced shifts of the majority of the vibrational modes are determined and compared with the corresponding ones of crystalline sulfur.

Laser-assisted growth of t-Te nanotubes and their controlled photo-induced unzipping to ultrathin core-Te/sheath-TeO(2) nanowires.

One dimensional (1D) nanostructures of semiconducting oxides and elemental chalcogens culminate over the last decade in nanotechnology owing to their unique properties exploitable in several applications sectors. Whereas several synthetic strategies have been established for rational design of 1D materials using solution chemistry and high temperature evaporation methods, much less attention has been given to the laser-assisted growth of hybrid nanostructures. Here, we present a laser-assisted method for the controlled fabrication of Te nanotubes.

Stability and physicochemical characterization of novel milk-based oral formulations.

Purpose: The purpose of this work was to assess the colloidal stability of novel milk-based formulations.

Methods: Milk-based formulations were prepared in situ by adding into milk alkaline- or ethanolic-drug solutions containing an array of drugs namely; ketoprofen, tolfenamic acid, meloxicam, tenoxicam and nimesulide, mefenamic acid, cyclosporine A, danazol and clopidogrel besylate. The produced formulations were characterized by means of dynamic lightscattering, ζ-potential studies, atomic force microscopy, fluorescence spectroscopy, Raman spectroscopy complemented with ab initio calculations and stability studies.

Chalcogenide glass layers in silica photonic crystal fibers.

We report a novel approach for deposition of amorphous chalcogenide glass films inside the cylindrical air channels of photonic crystal fiber (PCF). In particular, we demonstrate the formation of nanocolloidal solution-based As(2)S(3) films inside the air channels of PCFs of different glass-solvent concentrations for two fibers with cladding-hole diameter 3.5 and 1.

Nonergodicity factor, fragility, and elastic properties of polymeric glassy sulfur.

We present a detailed investigation of the vibrational dynamics of glassy sulfur (g-S). The large frequency range spanned in this study has allowed us to carefully scrutinize the elastic properties of g-S and to analyze their relation to various features of both the glassy and the liquid state. In particular, the acoustic properties of g-S present a quasi-harmonic behavior in the THz frequency range, while at lower frequency, in the GHz range, they are affected by a strong anharmonic contribution.

Composition-dependent photosensitivity in As-S glasses induced by bandgap light: structural origin by Raman scattering.

Massive photoinduced short- and medium-range structural changes (photopolymerization) in As-S glasses are induced by near-bandgap light and studied by Raman scattering. Structural changes involve bond restructuring in sulfur-rich nanodomains of these nanoscale-phase-separated glasses. The spectral dependence of the photopolymerization effect demonstrates that various wavelengths can be used to optically change the structure of As-S glasses.

Vibrational dynamics and surface structure of amorphous selenium.

In contrast to crystalline solids in which structural order governs dynamics and thermodynamics, the lack of long-range periodicity in amorphous materials is responsible for several anomalies. Although the relation between these anomalies and the 'bulk structure' is generally understood, the surface structure and the corresponding vibrational spectrum of amorphous solids is practically an unexplored theme. In this study, we resolve the differences in vibrational dynamics and atomic structure between bulk and surface (top 5  nm) atoms of amorphous selenium.

Stabilisation of SWNTs by alkyl-sulfate chitosan derivatives of different molecular weight: towards the preparation of hybrids with anticoagulant properties.

We have previously demonstrated that chitosan derivative N-octyl-O-sulfate chitosan (NOSC), which presents important pharmacological properties, can suspend single walled carbon nanotubes (SWNTs) up to 20 times more effectively than other chitosan derivatives in an aqueous environment. In an attempt to further investigate the impact of different molecular weights of chitosan to the solubilization and anticoagulant properties of these hybrids an array of NOSC derivatives varying their molecular weight (low, medium and high respectively) was synthesised and characterised by means of FT-IR spectroscopy, NMR spectroscopy and thermal gravimetric analysis (TGA). Microwave and nitric acid purified SWNTs, characterised by FT-IR spectroscopy, transmission electron microscopy (TEM) and Raman spectroscopy, were colloidally stabilised by these polymers and their anticoagulant activity was assessed.

Novel composites materials from functionalized polymers and silver coated titanium oxide capable for calcium phosphate induction, control of orthopedic biofilm infections: an "in vitro" study.

Three copolymers containing the functional groups P=O, S=O and C=O were prepared, and upon the introduction in calcium phosphate aqueous solutions at physiological conditions, "in vitro" were induced the precipitation of calcium phosphate crystals. The investigation of the crystal growth process was done at constant supersaturation. It is suggested that the negative end of the above functional groups acts as the active site for nucleation of the inorganic phase.

Physisorbed o-carborane onto lyso-phosphatidylcholine-functionalized, single-walled carbon nanotubes: a potential carrier system for the therapeutic delivery of boron.

A combination of data from ICP-MS, Raman spectroscopy, UV-vis spectrometry, atomic force microscopy, zeta-potential measurements and gel electorphoresis studies has shown that o-carborane may be immobilized on stable aqueous dispersions of lyso-phosphatidylcholine-functionalized single-walled carbon nanotubes, which in turn indicates the potential of such structures for deployment as carrier vehicles in boron neutron capture therapy.

High pressure transition in amorphous As(2)S(3) studied by EXAFS.

We report an in situ high pressure investigation of the structural change in vitreous As(2)S(3) up to 60 GPa using the diamond anvil cell and energy dispersive x-ray absorption spectroscopy. The main finding of the present study is a gradual elongation of the average As-S bond length, which takes place in the pressure range of 15-50 GPa. This change is interpreted as a signature of the coordination number increase around As atoms.

Comment on "Dynamic aspects of the liquid-liquid phase transformation in silicon" [J. Chem. Phys. 129, 104503 (2008)].

Recently, Jakse and Pasturel [J. Chem. Phys.