Eects of State of Charge on the Physical Characteristics of V(IV)/V(V) Electrolytes and Membrane for the All Vanadium Flow Battery

The VO2+/VO2+ redox couple commonly employed on the positive terminal of the all-vanadium redox flow battery was investigated at various states of charge (SOC) and H2SO4 supporting electrolyte concentrations. Electron paramagnetic resonance was used to investigate the VO2+ concentration and translational and rotational diffusion coefficient (DT, DR) in both bulk solution and Nafion membranes. Values of DT and DR were relatively unaffected by SOC and on the order of 10−10 m2s−1. Cyclic voltammetry measurements revealed that no significant changes to the redox mechanism were observed as the state of charge increased; however, the mechanism does appear to be affected by H2SO4 concentration. Electron transfer rate (k0) increased by an order of magnitude (10−6 ms−1 to 10−8 ms−1) for each H2SO4 concentrations investigated (1, 3 and 5 M). Analysis of cyclic voltammetry switching currents suggests that the technique might be suitable for fast determination of state of charge if the system is well calibrated. Membrane uptake and permeability measurements show that vanadium absorption and crossover is more dependent on both acid and vanadium concentration than state of charge. Vanadium diffusion in the membrane is about an order of magnitude slower (~10−11 m2s−1) than in solution (~10−10 m2s−1)

A Bacillus subtilis cell fraction (BCF) inducing calcium carbonate precipitation: biotechnological perspectives for monumental stone reinforcement

Abstract Monumental stone decay is a consequence of the weathering action of physical, chemical and biological factors, which induce a progressive increase in porosity. To cope this degradation, bacterial calcium carbonate mineralization has been proposed as a tool for the conservation of monumental calcareous stones. The advantage of this kind of treatment is to obtain a mineral product similar to the stone substrate, mimicking the natural process responsible for stone formation. In this work, the possibility to induce CaCO3 mineralization by a bacteria-mediated system in absence of viable cells was investigated and tested on stone. Our results showed that Bacillus subtilis dead cells as wells as its bacterial cell wall fraction (BCF) can act as calcite crystallization nuclei in solution. BCF consolidating capability was further tested in laboratory on slab stones, and in situ on the Angera Church, a valuable 6th century monumental site. New crystals formation was observed inside pores and significant decrease in water absorption (up to 16.7%) in BCF treated samples. A little cohesion increase was observed in the treated area of the Angera Church, showing the potential of this application, even though further improvements are needed

Black microcolonial fungi as deteriogens of two famous marble statues in Florence, Italy

Blackened areas on outdoor marble statues are a significant esthetic problem due to the presence of deteriorating agents. Microcolonial black fungi, which have their natural ecological niche on rocks, play an important role in deterioration of stones used in monuments, such as marble and limestone. Black fungi were isolated from two very valuable statues exposed to the outdoor environment in Florence, Italy, the "Ratto delle Sabineâ" and the "Copia del David", and these fungi were demonstrated to be responsible for the blackening areas on the statues. The black strains showed many features common to members of rock-inhabitants dematiaceous fungi. Morphological and molecular characterization, including phylogenetic analysis, indicated that the strains isolated from both statues and in different times belong to the same species and can be assigned to the rock-inhabitant genera Sarcinomyces and Phaeococcomyces. Red yeasts growing in close proximity to the black ones, with no visible effect on the statues, were also characterized on the morphological and molecular level and identified as Sporobolomyces yunnanensis

The Effect of Sulfuric Acid Concentration on the Physical and Electrochemical Properties of Vanadyl Solutions

The effects of sulfuric acid concentration in VO2+ solutions were investigated via electrochemical methods and electron paramagnetic resonance. Viscosity of solutions containing 0.01 M VOSO4 in 0.1–7 M H2SO4 was measured. Diffusion coefficients were independently measured via electrochemical methods and EPR with excellent agreement between the techniques employed and literature values. Analysis of cyclic voltammograms suggest the oxidation of VO2+ to VO2+ is quasi-reversible at high H2SO4 concentrations (\u3e5 mol/L) and approaching irreversible at lower H2SO4 concentrations. Further analysis reveals a likely electrochemical/chemical (EC) mechanism where the H2SO4 facilitates the electrochemical step but hinders the chemical step. Fundamental insights of VO2+/H2SO4 solutions can lead to a more comprehensive understanding of the concentration effects in electrolyte solutions

Aquatic Respiration Rate Measurements at Low Oxygen Concentrations

Despite its huge ecological importance, microbial oxygen respiration in pelagic waters is little studied, primarily due to methodological difficulties. Respiration measurements are challenging because of the required high resolution of oxygen concentration measurements. Recent improvements in oxygen sensing techniques bear great potential to overcome these limitations. Here we compare 3 different methods to measure oxygen consumption rates at low oxygen concentrations, utilizing amperometric Clark type sensors (STOX), optical sensors (optodes), and mass spectrometry in combination with 18-18O2 labeling. Oxygen concentrations and consumption rates agreed well between the different methods when applied in the same experimental setting. Oxygen consumption rates between 30 and 400 nmol L−1 h−1 were measured with high precision and relative standard errors of less than 3%. Rate detection limits in the range of 1 nmol L−1 h−1 were suitable for rate determinations in open ocean water and were lowest at the lowest applied O2 concentration

Coenzyme Q10 treatment in infertile men with idiopathic asthenozoospermia: a placebo-controlled, double-blind randomized trial

OBJECTIVE: To evaluate the effectiveness of coenzyme Q(10) treatment in improving semen quality in men with idiopathic infertility. DESIGN: Placebo-controlled, double-blind randomized trial. SETTING: Andrology Unit, Department of Internal Medicine, Polytechnic University of Marche, Italy. PATIENT(S): Sixty infertile patients (27-39 years of age) with the following baseline sperm selection criteria: concentration >20 x 10(6)/mL, sperm forward motility 30%; 55 patients completed the study. INTERVENTION(S): Patients underwent double-blind therapy with coenzyme Q(10), 200 mg/day, or placebo; the study design was 1 month of run-in, 6 months of therapy or placebo, and 3 months of follow-up. MAIN OUTCOME MEASURE(S): Variations in semen parameters used for patient selection and variations of coenzyme Q(10) and ubiquinol concentrations in seminal plasma and spermatozoa. RESULT(S): Coenzyme Q(10) and ubiquinol increased significantly in both seminal plasma and sperm cells after treatment, as well as spermatozoa motility. A weak linear dependence among the relative variations, baseline and after treatment, of seminal plasma or intracellular coenzyme Q(10) and ubiquinol levels and kinetic parameters was found in the treated group. Patients with a lower baseline value of motility and levels of coenzyme Q(10) had a statistically significant higher probability to be responders to the treatment. CONCLUSION(S): The exogenous administration of coenzyme Q(10) increases the level of the same and ubiquinol in semen and is effective in improving sperm kinetic features in patients affected by idiopathic asthenozoospermia

A Common Mechanism Underlying the E1A Repression and the cAMP Stimulation of the H Ferritin Transcription

Transcription of the H ferritin gene in vivo is stimulated by cAMP and repressed by the E1A oncoprotein. We report here the identification of the cis-element in the human promoter responsive to both cAMP- and E1A-mediated signals. This promoter region is included between positions -62 to -45 and binds a approximate 120-kDa transcription factor called Bbf. Bbf forms a complex in vivo with the coactivator molecules p300 and CBP. Recombinant E1A protein reduces the formation of these complexes. In vivo overexpression of p300 in HeLa cells reverses the E1A-mediated inhibition of the ferritin promoter transcription driven by Bbf. These data suggest the existence of a common mechanism for the cAMP activation and the E1A-mediated repression of H ferritin transcription

A Ten-Fold Solvent Kinetic Isotope Effect for the Nonradiative Relaxation of the Aqueous Ferrate(VI) Ion

Hypervalent iron intermediates have been invoked in the catalytic cycles of many metalloproteins, and thus it is crucial to understand how the coupling between such species and their environment can impact their chemical and physical properties in such contexts. In this 2 work, we take advantage of the solvent kinetic isotope effect (SKIE) to gain insight into the nonradiative deactivation of electronic excited states of the aqueous ferrate(VI) ion. We observe an exceptionally large SKIE of 9.7 for the nanosecond-scale relaxation of the lowest energy triplet ligand field state to the ground state. Proton inventory studies demonstrate that a single solvent O-H bond is coupled to the ion during deactivation, likely due to the sparse vibrational structure of ferrate(VI). Such a mechanism is consistent with that reported for the deactivation of f-f excited states of aqueous trivalent lanthanides, which exhibit comparably large SKIE values. This phenomenon is ascribed entirely to dissipation of energy into a higher overtone of a solvent acceptor mode, as any impact on the apparent relaxation rate due to a change in solvent viscosity is negligible

Responding to the crisis: are policies aimed at a strong indigenous industrial base a necessary condition for sustainable economic growth?

peer-reviewedWe examine whether a strong indigenous manufacturing base is a necessary condition for sustainable economic growth in the case of two small, open economies, Ireland and Sweden. Sweden has been impacted by the economic crisis to a lesser degree than Ireland; we explore (through a manufacturing activity lens) the reasons for the asymmetric impacts and ask if the nature of the shock is related to 'Economic Sovereignty' and to the type of industrial policy. We argue Sweden was less affected given that its indigenous firms control the highly export-focused and technology-based engineering sector whereas in Ireland high-technology sectors are controlled by foreign firms. In terms of policy implications, we suggest that industrial policy should aim for sustainable economic activity and growth such that industrial activity within the economy should be able to minimise the impact of asymmetric shocks such as the current global economic recession.ACCEPTEDpeer-reviewe