Who profits from the Canadian nanotechnology reward system? Implications for gender-responsible innovation

Scientometrics - Gender equality is one of the primary dimensions of responsible research and innovation. Based on bibliometric and survey data of nanotechnology researchers in Canada, this paper...     

Long-range electron tunnelling in oligo-porphyrin molecular wires

Short chains of porphyrin molecules can mediate electron transport over distances as long as 5-10 nm with low attenuation. This means that porphyrin-based molecular wires could be useful in nanoelectronic and photovoltaic devices, but the mechanisms responsible for charge transport in single oligo-porphyrin wires have not yet been established. Here, based on electrical measurements of single-molecule junctions, we show that the conductance of the oligo-porphyrin wires has a strong dependence on temperature, and a weak dependence on the length of the wire. Although it is widely accepted that such behaviour is a signature of a thermally assisted incoherent (hopping) mechanism, density functional theory calculations and an accompanying analytical model strongly suggest that the observed temperature and length dependence is consistent with phase-coherent tunnelling through the whole molecular junction.     

Some fixed point theorems for maps with fuzzy distance in uniform space

The purpose of this paper is to define the notion of fuzzy A-distance in uniform spaces and give several new common fixed point results for weakly compatible contractive or expansive selfmappings on uniform spaces.     

The Investigation of the Weak Link Behavior in the Niobium (Nb) Doped Bi1.6Pb0.4Sr2Ca2Cu3O δ Superconductor

The Nb substitution effect on structural, DC electrical resistivity, and AC susceptibility properties of polycrystalline Bi_1.6Pb_0.4Sr₂Ca₂Cu₃O _δ samples is investigated. The behavior of weak link and intergranular coupling in the substituted samples is discussed. While the Bi-2223 phase concentration increases in the X-ray diffraction (XRD) pattern, the intragrain transition temperature remains nearly unchanged in the substituted samples. The intergrain transition temperature is changed with Nb substitution.     

Effects of preparation conditions on the morphology and gas permeation properties of polyethylene (PE) and ethylene vinyl acetate (EVA) films

In this study, the effect of film preparation conditions on the gas permeation properties of polyethylene (PE) and ethylene vinyl acetate (EVA) films (containing 18 and 28 wt% vinyl acetate) was investigated. Film blowing and phase inversion methods were applied in the production of PE and EVA films, respectively. The permeation of pure oxygen and carbon dioxide gases was measured at room temperature. The results indicated that with the increase of PE film thickness, permeability and solubility of O₂ and CO₂ in these films decreased; but the diffusivities of gases through PE films increased. In addition, in the case of EVA copolymers, by increasing the content of vinyl acetate, the permeability of CO₂ increased. The rate of increase in CO₂ permeability was different for samples having different preparation conditions. For example, the samples prepared using chloroform as the solvent instead of THF, showed lower CO₂ permeability. Also, the morphological studying of film structure indicated that the higher CO₂ permeability for the samples made from THF solvent is due to the existing of higher porosity in the under layer polymer area. Also scanning electron microscopy (SEM) micrographs showed that with the usage of phase inversion method, there will be a thin dense layer near to the glass substrate.     

Egg yolk conjugated linoleic acid alters phospholipid molecular species in chick tissues

The effects of egg conjugated linoleic acid (CLA) on chick yolk sac and liver phospholipid composition and molecular species were determined. Fertile eggs with no (control), low (CLA1) or high (CLA2) levels of CLA were incubated. Upon hatching, total lipid in the remnant yolk sac constituted 11.5, 18.9 and 15.3% in control, CLA1 and CLA2, respectively (p <0.05). Maternal CLA led to a decrease in phosphatidylcholine (PtdCho) and phosphatidylethanolamine (PtdEtn) and an increase in lysophosphatidylcholine (LPtdCho) in the yolk sac and liver tissues of CLA1 and CLA2 when compared to control (p <0.05). The effect of maternal dietary CLA was very prominent in yolk sac PtdCho (34:1) where 13 and 38% reductions were observed in CLA1 and CLA2, respectively, when compared to control. Among different liver PtdCho species, the highest difference was found in 36:2, where a 41% increase was observed in CLA2 when compared with control chicks. The liver LPtdCho of CLA1 and CLA2 chicks had a 92% increase in 16:0 and 18:0 when compared to control. Over 80% increase was observed for 18:2 and 20:4 in the liver LPtdCho of CLA2 chicks compared to control. These results suggest that the yolk CLA content alters the proportions of phospholipids in the progeny during avian embryogenesis.     

Natural Load Indices (NLI) for scientific simulation

We present Natural Load Indices (NLIs) as an alternative to measurement-based load indices. NLIs facilitate further performance improvement and better resource usage. Example NLIs are rainfall amounts in a climate simulation, mass of an atom in a Molecular Dynamics (MD) code and surface fluxes in an ocean model. The process of obtaining an NLI occurs during model development or as a preprocessing step and implementing NLIs minimizes run-time costs associated with dynamic load balancing.     

Removal of toxic nitrate ions from drinking water using conducting polymer/MWCNTs nanocomposites

New application of conducting polymers as stable nanocomposites for nitrate ion exchange materials in water and wastewater treatment and for environmental protection is introduced in this work. The nanocomposites of multi-walled carbon nanotubes (MWCNTs) with different polymers such as: polyaniline (PANI), polypyrrole (PPY), poly(1,8-diaminonaphthalene) [P(1,8-DAN)] and poly(2-vinylpyridine) (P2VP) were synthesized with different dopants as effective and reusable nanocomposites for nitrate removal from drinking water. Nitrate anions at toxic concentrations were removed from water using ion exchange mechanism without any toxic byproducts. The obtained results demonstrate that effective ion exchange occurs between NO₃ ^? and Cl^?. There are some protonated heteroatoms in polymer chains that are bonded with anions of dopants and their counter ions in nanocomposites. These dopant anions on the =NH⁺– groups of polymers can be exchanged with NO₃ ^? in water. Adsorption of NO₃ ^? on polymer/MWCNTs nanocomposites showed dependency to some parameters. Different experimental parameters such as pH and temperature of the sample, polymers dopant, and the ratio of polymer to MWCNTs in nanocomposites affect the amount of nitrate removal. The highest removal efficiency was achieved at 1.20 g L^?1 of PANI/MWCNTs (3:1) nanocomposite, pH = 6.5 and ambient temperature. After five successive cycles of nitrate removal, this parameter was still up to 70 % compared to the first run (up to 80 %).     

Synthesis of conducting water‐soluble polyaniline with iron(III) porphyrin

The porphyrin‐catalyzed, template‐guided polymerization of aniline was carried out in an aqueous buffer solution. Hydrogen peroxide and iron(III) tetrasulfonated tetraphenyl porphyrin catalyzed the polymerization of aniline in the presence of sulfonated polystyrene as a template. The polymerization was carried out at different pHs ranging from 1 to 5. Ultraviolet–visible spectroscopy indicated the formation of a conducting form of polyaniline. The extent of the polymerization increased with decreasing pH of the solution. The maximum absorbance of the polaron band at 750 nm was obtained at pH 2, but when the polymerization was performed with pH 4, this band shifted to a longer wavelength. These results confirmed that a longer chain length of polyaniline was obtained with pH 4. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 102: 2929–2934, 2006     

Polyisoprene-nanostructured carbon composite (PNCC) organic solvent vapour sensitivity and repeatability

In this paper highly structured carbon black (HSCB) dispersion method effect on polyisoprene-nanostructured carbon composite (PNCC) organic solvent vapour (OSV) sensitivity is presented. PNCC has been produced using two different HSCB dispersion techniques: (1) dry method: the HSCB dispersed in polyisoprene mixing ingredients by cold rolling and (2) wet method: the HSCB dispersed in chloroform by ultrasonic homogenizer and mixed with solution of rubber in chloroform by magnetic stirring. The sensitivity to OSV of the obtained PNCC is tested by holding the samples in vapour of toluene or ethyl acetate and measuring in situ electrical resistance, mass, and length of the sample. Obtained results indicate two mechanisms of the change of electrical resistance in PNCC. Repeatability of the response of PNCC is tested in case of toluene vapour.