Non-noble metal composite cathodes for hydrogen evolution. Part I: The Ni–MoOx coatings electrodeposited from Watt’s type bath containing MoO3 powder particles

In this work the Ni-MoO_x coatings have been prepared and characterized in view of their possible application as electrocatalysts for hydrogen evolution reaction (HER) in alkaline solution. The procedure of deposition of Ni-MoO_x coatings from the Watt’s type bath containing MoO₃ powder particles onto Ni mesh, under the conditions of simulated industrial deposition conditions for commercial cathodes, has been presented. The morphology of the obtained coatings was investigated by SEM, the composition by EDS and the phase composition by XRD techniques. The polarization characteristics for hydrogen evolution on the obtained Ni-MoO_x coatings were investigated in the 32 wt.% NaOH at 90 °C and compared with the one recorded for the commercial De Nora’s coating (DN). It was shown that the best Ni-MoO_x coating exhibits almost identical polarization characteristics as the commercial one. By the cross section and XRD analysis of deposited samples it was confirmed that MoO₃ powder particles were not occluded by the Ni deposit and that molybdenum species were deposited from the molybdate ions formed by dissolution of MoO₃, following the mechanism of induced co-deposition. The reaction mechanism for MoO₃ phase deposition has also been proposed.     

Regional economic dynamics and convergence in the European Union

This paper uses an alternative approach to convergence analysis, which, in our opinion, is richer than those traditionally proposed. We believe that the evolution of the whole regional distribution is what matters, not that of an average or representative economy, implicit in the or convergence concepts. Moreover, when analyzing inequality among regional economies, geographic space acquires a preeminent role. We therefore apply spatial association tests recently developed in the spatial econometrics literature and relate them to convergence analysis. Specifically, we apply this methodology to the analysis of regional dynamics and convergence in the European Union (EU). In this context, the progress made in the integration process has highlighted the question of economic disparities at regional level. The process of convergence came to an end in the late seventies, coinciding with major changes in economic activity. This paper shows how these factors appear to have provoked a regionally differentiated response which, though significant, did not, in all likelihood, exacerbate the decrease in regional inequalities.     

Substituted imino and amino derivatives of 4-hydroxycoumarins as novel antioxidant,antibacterial and antifungal agents: Synthesis and in vitro assessments

A series of imino and amino derivatives of 4-hydroxycoumarins were synthesised and evaluated for antioxidant potential, through different in vitro models such as (DPPH) free radical-scavenging activity, linoleic acid emulsion model system, reducing power assay and phosphomolybdenum method. Also, antimicrobial activity of obtained coumarins was evaluated against 13 bacteria and eight fungi. All prepared compounds possessed good antioxidant activity and among them a p-nitrophenol derivative with IC₅₀ at 25.9 μM possessed radical-scavenging activity which was comparable to BHT. Observed data for antibacterial activity indicated strong activity of all tested amino derivatives, while imines showed better antifungal properties.     

Performance Evaluation of an Improved Particle Size Magnifier (PSM) for Single Nanoparticle Detection

Several modifications of the particle size magnifier (PSM) developed by Okuyama et al. have been introduced recently for detection of particles at diameters of 1 nm and below. However, their evaluation has been incomplete. Here we provide the first direct measurements of counting efficiencies near unity below 2 nm. We use the modified PSM described by Sgro and Fernández de la Mora, which separates thermally the PSM's original vapor generator from the water-cooled growth chamber by means of a narrow and short T where turbulent mixing with the aerosol takes place. The counting efficiency is seen to depend greatly on the aerosol flow, the amount of vapor, and temperature. With ethylene glycol vapor, under optimal conditions, the counting efficiency is 100% down to 1.6 nm (actual diameter of 1.2 nm), and negative particles are more easily activated than positive particles. The improved PSM is applied to the measurement of gold nanoparticle size distributions, and the results show it is a powerful aerosol detector for nanoparticles.     

Identification of novel membrane structures in Plasmodium falciparum infected erythrocytes

Phosphorylation sites were introduced into chimeric monoclonal antibody CC49 (MAb-chCC49) by inserting synthetic fragments encoding two and six phosphorylation sites into an expression vector, pdHL7. The phosphorylation sites were created by using the predicted consensus sequences for phosphorylation by the cAMP-dependent protein kinase to the carboxyl terminus of the heavy chain constant region of the MAb-chCC49. The resultant modified antibodies (MAb-chCC49K1 and MAb-chCC49-6P) were expressed in NS0 cells and purified. The MAb-chCC49K1 protein contains two phosphorylation sites per heavy chain whereas the MAb-chCC49-6P protein contains six sites per heavy chain. Both MAb-chCC49K1 and MAb-chCC49-6P proteins can be phosphorylated by the catalytic subunit of cAMP-dependent protein kinase with [gamma-32P]ATP to high specific activity. The 32P-labeled MAb-chCC49K1 and MAb-chCC49-6P proteins bind to cells expressing TAG-72 antigens. The introduction of phosphorylation sites into a monoclonal antibody provides a reagent for the diagnosis and treatment of cancer. The use of multiple phosphorylation sites provides antibodies with very high specific radioactivity and demonstrates that cassettes of phosphorylation sites can be introduced into proteins without altering their functional activity.     

Enrichment of Anammox biomass from municipal activated sludge: experimental and modelling results

Anaerobic Ammonia Oxidising (Anammox) biomass was enriched from sludge collected at a municipal wastewater treatment plant, employing a Sequential Batch Reactor (SBR). After 60 days Anammox activity started to be detected, by consumption of stoichiometric amounts of NO₂^? and NH₄⁺ in the system. Fluorescence In Situ Hybridisation analysis confirmed the increase of Anammox bacteria concentration with time. A final concentration of enriched biomass of 3–3.5 gVSS dm^?3 was obtained, showing a Specific Anammox Activity of 0.18 gNH₄⁺‐N gVSS^?1 d^?1 The reactor was able to treat nitrogen loading rates of up to 1.4 kgN m^?3 d^?1, achieving a removal efficiency of 82 %. On the other hand, the start‐up and operation of the Anammox SBR reactor were consequentially modelled with the Activated Sludge Model nr 1, extended for Anammox. The simulations predicted quite well the experimental data in relation to the concentrations of nitrogenous compounds and can be used to estimate the evolution of Anammox and heterotrophic biomass in the reactor. These simulations reveal that heterotrophs still remain in the system after the start‐up of the reactor and can protect the Anammox microorganisms from a negative effect of the oxygen. Copyright © 2004 Society of Chemical Industry     

Heat transfer in photonic mirrors

The use of secondary mirrors in solar energy concentration is common. However, high concentrated solar radiation heats these mirrors thereby degrading their physical properties. In particular, aluminum mirrors melt because of high temperature due to storage by high radiative heat transfer. In contradistinction photonic crystals could present “perfect reflection” and they can be fabricated using porous silicon which has a higher melting point than aluminum (porous silicon has a melting point higher than 900 K). Porous silicon is a nanostructured semiconductor material which can be fabricated with different porosities and refractive indices. Multilayers of alternating periodic refractive index conform the structure of these photonic crystals. The light that propagates in these structures interacts with its periodic refractive index that generates wavelength gaps of forbidden transmission and so these multilayers conform a mirror. Even these photonic structures are heated when they are exposed to high concentrated solar radiation. In this work we experimentally analyze this heating process and model it using an effective medium approach to explain the increasing temperature behavior.     

Morphological, optical and photocatalytic properties of TiO2–Fe2O3 multilayers

Morphological, optical and photocatalytic properties of TiO₂, Fe₂O₃ and TiO₂–Fe₂O₃ samples (formed by 1, 3 and 5 coatings) were studied. The layers were deposited on glass substrate by the sol–gel method. The catalytic activity of the samples was studied by the photodecomposition of methylene blue (MB) under visible light illumination. The FTIR results indicate that all samples present surface OH radicals that are bound either to the Ti or Fe atoms. This effect is better visualized at larger number of coatings in the TiO₂–Fe₂O₃/glass systems. Also, two mechanisms are observed during the photodecomposition of the MB.     

Assessment of medical occupational radiation doses in Costa Rica

Participation of the University of Costa Rica (UCR) in activities in an IAEA Regional Project RLA/9/066 through training, equipment and expert missions, has enabled to setting up of a national personal monitoring laboratory. Since 2007, the UCR has been in charge of monitoring around 1800 medical radiation workers of the Social Security System. Individual external doses are measured with thermoluminescent dosemeter using a Harshaw 6600 Plus reader. The service has accreditation with ISO/IEC 17025:2005. Distribution of monitored medical personnel is as follows: 83 % in diagnostic radiology, 6 % in nuclear medicine and 6 % in radiotherapy. Preliminary values for the 75 percentile of annual H(p)(10) in mSv are: radiology 0.37; interventional radiology 0.41; radiotherapy 0.53 and nuclear medicine 1.55. The service provided by the UCR in a steady and reliable way can help to implement actions to limit the doses received by the medical workers and optimise their radiation protection programs.     

Characterizing the structure of pharmaceutical granules obtained by wet granulation with varying amounts of water via Raman chemical imaging

A pharmaceutical formulation containing metformin hydrochloride (MET), hydroxypropyl cellulose (HPC), and microcrystalline cellulose (MCC) was wet granulated with varying amounts of water and the structure of the obtained granules was characterized by Raman chemical mapping. Univariate Raman mapping was found to be satisfactory for producing the images of the two components of interest (HPC and MCC). In addition to the images, the average Raman spectra from the maps as well as the micro-Raman spectra from the hot pixels were analyzed. HPC is found to strongly respond to the addition of water, with its domain dissipating and Raman bands becoming weaker as the water addition increases. MCC is also responsive to water, reacting similarly to HPC but to a much smaller extent and only for the largest amounts of water. Granules made with increasing water content also have improved tabletting properties and flow.