Transparent and flexible, nanostructured and mediatorless glucose/oxygen enzymatic fuel cells

Here we detail transparent, flexible, nanostructured, membrane-less and mediator-free glucose/oxygen enzymatic fuel cells, which can be reproducibly fabricated with industrial scale throughput. The electrodes were built on a biocompatible flexible polymer, while nanoimprint lithography was used for their nanostructuring. The electrodes were covered with gold, their surfaces were visualised using scanning electron and atomic force microscopies, and they were also studied spectrophotometrically and electrochemically. The enzymatic fuel cells were fabricated following our previous reports on membrane-less and mediator-free biodevices in which cellobiose dehydrogenase and bilirubin oxidase were used as anodic and cathodic biocatalysts, respectively. The following average characteristics of transparent and flexible biodevices operating in glucose and chloride containing neutral buffers were registered: 0.63 V open-circuit voltage, and 0.6 mu W cm(-2) maximal power density at a cell voltage of 0.35 V. A transparent and flexible enzymatic fuel cell could still deliver at least 0.5 mu W cm(-2) after 12 h of continuous operation. Thus, such biodevices can potentially be used as self-powered biosensors or electric power sources for smart electronic contact lenses. (C) 2015 Elsevier B.V. All rights reserved

Approaching microwave photon sensitivity with Al Josephson junctions

Here, we experimentally test the applicability of an aluminium Josephson junction of a few micrometers size as a single photon counter in the microwave frequency range. We have measured the switching from the superconducting to the resistive state through the absorption of 10 GHz photons. The dependence of the switching probability on the signal power suggests that the switching is initiated by the simultaneous absorption of three and more photons, with a dark count time above 0.01 s

Chlorine Adsorption on TiO2(110)/Water Interface: Nonadiabatic Molecular Dynamics Simulations for Photocatalytic Water Splitting

This study was financially supported M-ERA.NET project CatWatSplit. Institute of Solid State Physics, University of Latvia, as the Center of Excellence, has received funding from the European Union’s Horizon 2020 Framework Program H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under Grant Agreement No. 739508, project CAMART2. The calculations were performed at the Latvian SuperCluster (LASC) located in Institute of Solid State Physics, University of Latvia.Chloride is one of the most abundant ions in sea water, which is more available than fresh water. Due to lack of H2O adsorbate states near the valence band maximum (VBM) edge, the difficulty of water dissociation incidents has been reported on the rutile TiO2 surface as the excitation energy is around the band gap energy of TiO2. It is interesting whether the extra chloride can be a benefit to the water dissociation or not. In this study, the models of chlorine adatoms placed on the rutile TiO2 (110)/water interface are constructed using ab initio methods. The time-dependent spatial charges, bond-lengths of water molecules, and Hirshfeld charges are calculated by real-time time-dependent density functional theory and the Ehrenfest dynamics theory for investigating the excited state nonadiabatic dynamics of water dissociation. This study presents two photoinduced water-splitting pathways related to chlorine and analyzes the photogenerated hole along the reactions. The first step of water dissociation relies on the localized competition of oxygen charges between the dissociated water and the bridge site of TiO2 for transforming the water into hydroxyl and hydrogen by photoinduced driving force. --//-- This is an open access article Y.-P. Lin, D. Bocharov, I. Isakoviča, V. Pankratov, A.A. Popov, A.I. Popov, S. Piskunov; Chlorine adsorption on TiO2(110)/water interface: Nonadiabatic molecular dynamics simulations for potocatalytic water splitting; Electron. Mater., 2023, 4, pp. 33-48; DOI: 10.3390/electronicmat4010004; https://www.mdpi.com/2673-3978/4/1/4 published under the CC BY 4.0 licence.M-ERA.NET project CatWatSplit; Institute of Solid State Physics, University of Latvia, as the Center of Excellence, has received funding from the European Union’s Horizon 2020 Framework Program H2020-WIDESPREAD-01-2016-2017-TeamingPhase2 under Grant Agreement No. 739508, project CAMART2

Eco-friendly iron-humic nanofertilizers synthesis for the prevention of iron chlorosis in soybean (Glycine max) grown in calcareous soil

Iron deficiency is a frequent problem for many crops, particularly in calcareous soils and iron humates are commonly applied in the Mediterranean basin in spite of their lesser efficiency than iron synthetic chelates. Development and application of new fertilizers using nanotechnology are one of the potentially effective options of enhancing the iron humates, according to the sustainable agriculture. Particle size, pH, and kinetics constrain the iron humate efficiency. Thus, it is relevant to understand the iron humate mechanism in the plant–soil system linking their particle size, characterization and iron distribution in plant and soil using 57Fe as a tracer tool. Three hybrid nanomaterials (F, S, and M) were synthesized as iron-humic nanofertilizers (57Fe-NFs) from leonardite potassium humate and 57Fe used in the form of 57Fe(NO3)3 or 57Fe2(SO4)3. They were characterized using Mössbauer spectroscopy, X-ray diffraction (XRD), extended X-ray absorption fine structure spectroscopy (EXAFS), transmission electron microscopy (TEM) and tested for iron availability in a calcareous soil pot experiment carried out under growth chamber conditions. Three doses (35, 75, and 150 mmol pot-1) of each iron-humic material were applied to soybean iron deficient plants and their iron nutrition contributions were compared to 57FeEDDHA and leonardite potassium humate as control treatments. Ferrihydrite was detected as the main structure of all three 57Fe- NFs and the plants tested with iron-humic compounds exhibited continuous long-term statistically reproducible iron uptake and showed high shoot fresh weight. Moreover, the 57Fe from the humic nanofertilizers remained available in soil and was detected in soybean pods. The Fe-NFs offers a natural, low cost and environmental option to the traditional iron fertilization in calcareous soilsThe Russian Science Foundation (16-14-00167), the Russian Foundation for Basic Research (18-29-25065), and the Spanish Ministry of Science and Innovation (AGL2013-44474-R) have financially supported this research

Self-charging biosupercapacitors

The thesis is focused on an entirely new class of electric power biodevices – self-charging biosupercapacitors, or in other words, charge-storing biofuel cells. The power generating segments of these biodevices rely on different redox enzymes electrically wired to electrode surfaces. Planar electrodes were additionally nanostructured by gold nanoparticles to increase the real surface area/enhance enzyme loading. Bilirubin oxidase was used as a cathodic biocatalyst responsible for oxygen electroreduction, whereas cellobiose dehydrogenase and glucose dehydrogenase were exploited as anodic bioelements catalyzing electrooxidation of glucose. The charge-storing segments of biosupercapacitors were based on different electroconducting polymers, including carbon nanotube based nanocomposites, and osmium modified redox hydrogels. The particular bioelectrodes were characterized in detail using scanning electron and atomic force microscopies, as well as various electrochemical techniques. Self-charging biosupercapacitors were assembled and basic parameters of the biodevices, viz. open-circuit voltages, power and charge densities, and stability, were studied in continuous and pulse operating modes

Self-charging biosupercapacitors

The thesis is focused on an entirely new class of electric power biodevices –self-charging biosupercapacitors, or in other words, charge-storing biofuelcells. The power generating segments of these biodevices rely on differentredox enzymes electrically wired to electrode surfaces. Planar electrodes wereadditionally nanostructured by gold nanoparticles to increase the real surfacearea/enhance enzyme loading. Bilirubin oxidase was used as a cathodicbiocatalyst responsible for oxygen electroreduction, whereas cellobiosedehydrogenase and glucose dehydrogenase were exploited as anodicbioelements catalyzing electrooxidation of glucose. The charge-storingsegments of biosupercapacitors were based on different electroconductingpolymers, including carbon nanotube based nanocomposites, and osmiummodified redox hydrogels. The particular bioelectrodes were characterized indetail using scanning electron and atomic force microscopies, as well asvarious electrochemical techniques. Self-charging biosupercapacitors wereassembled and basic parameters of the biodevices, viz. open-circuit voltages,power and charge densities, and stability, were studied in continuous andpulse operating modes

Dataset for "Parametric conversion via second harmonic generation and two-hump solitons in phase-matched microresonators"

The present dataset includes all figures (.fig and .png versions) represented in the "Parametric conversion via second harmonic generation and two-hump solitons in phase-matched microresonators" paper and the data used there. The most valuable part of the dataset is dynamics simulation described in the paper, showing the appearance of Turing-pattern-like states and solitons in the chi2 microring resonator.Full details of the methodology may be found in the section II 'Model' of the associated paper.All simulations were performed with MATLAB software. Simulation parameters could be found in the section I of the associated paper

Reductive Smelting of Neutralized Red Mud for Iron Recovery and Produced Pig Iron for Heat-Resistant Castings

The chemical and mineral composition of the red mud from the Ural Aluminum Plant were studied by XRF, XRD, and Mössbauer spectroscopy. Experiments on reductive smelting of red mud were carried out in a range of temperatures (1650–1750 °C) to recover iron from the aluminum production waste with maximum efficiency. It was found that it is possible to obtain pig iron with a high content of titanium, phosphorus, and vanadium, and low sulfur content. The efficiency of iron recovery at 1750 °C was found to be around 98%. Thermodynamic calculations were carried out to assist in finding the optimal conditions for the process (e.g., carbon content, furnace temperature, slag liquidus temperature). It was also found that the pig iron phase obtained at 1650 to 1700 °C is not separated from the slag phase into ingot compared with the sample obtained at 1750 °C. Pig iron obtained at 1750 °C can be used to produce molds for the steel-casting equipment