Thermal stability of metal-supported catalysts for reduction of cold-start emissions in a wood-fired domestic boiler

The aim of the present work is to develop a catalyst based on a mixture of manganese oxides and platinum supported on a metallic monolith for abatement of emissions from wood combustion, particularly during the cold-start phase. The activity and the thermal stability of the catalysts have been studied in the laboratory, before performing tests in a wood-stove. The effect of the hydrothermal treatment at 900°C on the adherence of the washcoat onto a metallic substrate was studied using scanning electronic microscope. It revealed well-adhering washcoat onto the metallic support due to the growth of the alumina whiskers during the treatment. The influence of the amount of washcoat, as well as the influence of the concentration of manganese oxides in it (Mn: 5 to 20 mol%/Al₂O₃) on the activity of fresh and hydrothermally-treated catalysts were studied. The activity tests were carried out using a mixture of carbon monoxide, naphthalene and methane in the presence of air, steam and carbon dioxide to resemble the flue gases from wood combustion. On the fresh catalysts, containing the same total amount of manganese, a high concentration of manganese oxides in the washcoat favoured the oxidation of carbon monoxide and naphthalene, whereas a lower concentration of manganese oxides in the washcoat gave higher activity for the oxidation of methane. An increased total amount of manganese oxides in the catalysts, which had the same amount of washcoat, resulted in an increase in activity for the oxidation of the three combustibles. After thermal treatment at 900°C for 270 h in steam, most of the manganese oxide catalysts were activated for the oxidation of carbon monoxide and naphthalene while only being slightly deactivated for the oxidation of methane. The addition of manganese oxides in the washcoat, however, lowers the temperature of the γ- to -alumina phase transformation. Platinum (0.5 mol%) was added to the manganese oxide (10 mol%) catalyst to improve its activity. A platinum catalyst was also tested for comparison. The platinum and the mixed catalysts showed similar activity for the oxidation of carbon monoxide and naphthalene, while the mixed catalysts were more active for the oxidation of methane. A similarly mixed MnO_x–Pt (10–0.5 mol%) catalyst supported on Al₂O₃ stabilised with 3% lanthanum, but at larger scale, was tested in a wood-stove. The possibility of pre-heating the catalyst during the start-up phase was studied. The tests revealed a strong decrease of the carbon monoxide and unburned hydrocarbons emissions during the start-up phase when the catalyst was pre-heated with hot air compared with no pre-heating or no catalyst.     

Integration in Europe of human genetics results obtained by Spaniards in the USA: A historical perspective

The mobility of Spanish biochemists from Europe to the United States over the past 80 years (1927–2006) is approached from a historical perspective. The academic community on human genetics has awarded this emigrated Spanish community with the Nobel prize as well as other awards from European foundations. The vertical/horizontal integration methodology offers an opportunity to understand the extremely satisfactory history of a small European community overseas. To piece the puzzle together, continuous reference is made to the theory of systems. To test and use this holistic history, the circulation of the knowledge produced on cancer has been studied as intrinsically related to time by using the algorithmic historiography. Francisco Duran Reynals and Severo Ochoa have been selected as examples of the vertical integration. The former one because he was the director of an important collaborator, his own wife; the latter, as the founder of a Spanish specific research school in America based in his own work. The simultaneous stay of several young Spanish scientists at the Columbia University (Mariano Barbacid, Manuel Perucho and ángel Pellicer) serves to design the horizontal integration, to create a holon hierarchy to reflect the criteria of subsidiarity and acceptability, and to focus on the Spanish discoveries and contributions to cancer research. The transatlantic flows of knowledge generated by the Spanish elite of biochemists in the USA from 1927 on define a network of geographical displacements. As a result, the social structure thus visualizes the identity of the international mobility of scientists who leave for Europe/USA, and their return to Spain. A model of the brain drain of professionals to the USA, that retain 80% of the Spanish cancer researchers, is developed. A version of theis paper was a contribution to: 2nd International Conference of the European Society for the History of Science (Cracow, Sept. 2006).     

New,Non‐quinone Fluorogeldanamycin Derivatives Strongly Inhibit Hsp90

Streptomyces hygroscopicus is a natural producer of geldanamycin. Mutasynthetic supplementation of an AHBA‐blocked mutant with all possible monofluoro 3‐aminobenzoic acids provided new fluorogeldanamycins. These showed strong antiproliferative activity and inhibitory effects on human heat shock protein Hsp90. Binding to Hsp90 in the low nanomolar range was determined from molecular modelling, AFM analysis and by calorimetric studies.     

Formulation Optimization of a Palm-Based Nanoemulsion System Containing Levodopa

Response surface methodology (RSM) was utilized to investigate the influence of the main emulsion composition; mixture of palm and medium-chain triglyceride (MCT) oil (6%–12% w/w), lecithin (1%–3% w/w), and Cremophor EL (0.5%–1.5% w/w) as well as the preparation method; addition rate (2–20 mL/min), on the physicochemical properties of palm-based nanoemulsions. The response variables were the three main emulsion properties; particle size, zeta potential and polydispersity index. Optimization of the four independent variables was carried out to obtain an optimum level palm-based nanoemulsion with desirable characteristics. The response surface analysis showed that the variation in the three responses could be depicted as a quadratic function of the main composition of the emulsion and the preparation method. The experimental data could be fitted sufficiently well into a second-order polynomial model. The optimized formulation was stable for six months at 4 °C.     

A novel approach to correlation reflectometry

The use of microwave synthesized sources improved significantly the performance of correlation reflectometry diagnostics for fusion plasmas providing broadband operation with high quality signals and fast frequency switching times. Recent new developments of those sources made at IPFN opened an all-new way to build correlation reflectometry diagnostics with improved performance and measuring capability. Some of the key features now attainable are independent probing and local oscillator signals generated by separated frequency synthesizers; very good frequency control and synchronization of both the local and the radio-frequency oscillators providing very high stability. The technological advances make it possible to further reduce the switching time between adjacent probing frequencies while keeping the ability to operate in a broad frequency range.Here we present a multichannel correlation system based on those novel technologies using several independent and self-contained fully synthesized broadband channels. With this type of system various type of measurements are possible: (i) fast stepwise radial scans to extract the radial profile of turbulence parameters (spectra, RMS, rotation from Doppler shift, etc.); (ii) radial scans of the plasma using two identical systems in parallel where one system operates in frequency steps and the other makes multiple small steps around each selected frequency of the first system. The proposed diagnostic is very powerful and versatile. With a system having n identical channels, all transmitting and receiving simultaneously, the number of simultaneous correlations measurements that can be performed is given by n × (n ? 1)/2. The minimal configuration uses two channels thus providing one (time domain) correlation signal channels can be easily added at any time increasing the measuring capability of the diagnostic. Several examples are given that illustrate the wide range of measurements that can be made using the novel approach for correlation reflectometry diagnostics.     

Adhesion, spreading and osteogenic differentiation of mesenchymal stem cells cultured on micropatterned amorphous diamond, titanium, tantalum and chromium coatings on silicon

It was hypothesized that human mesenchymal stromal cell (hMSC) can be guided by patterned and plain amorphous diamond (AD), titanium (Ti), tantalum (Ta) and chromium (Cr) coatings, produced on silicon wafer using physical vapour deposition and photolithography. At 7.5 h hMSCs density was 3.0–3.5× higher (P < 0.0003, except Ti) and cells were smaller (68 vs. 102 μm, P 0.000006–0.02) on patterns than on silicon background. HMSC-covered surface of the background silicon was lower on Ti than AD patterns (P = 0.015), but at 5 days this had reversed (P = 0.006). At 7.5 h focal vinculin adhesions and actin cytoskeleton were outgoing from pattern edges so cells assumed geometric square shapes. Patterns allowed induced osteogenesis, but less effectively than plain surfaces, except for AD, which could be used to avoid osseointegration. All these biomaterial patterns exert direct early, intermediate and late guidance on hMSCs and osteogenic differentiation, but indirect interactions exist with cells on silicon background.     

Colours in La Boca: Patrimonial identity in the Urban landscape

This article explores the chromatic reconstruction of La Boca neighborhood of Buenos Aires, Argentina and seeks to protect its patrimonial heritage. This article is organized into three parts: an Introduction, a section entitled Searching for Colours, and a Conclusion. The Introduction explains the historical factors contributing to the large‐scale Italian immigration that settled in La Boca neighborhood as well as their influence in shaping the character and landscape of the area. This section also comments on the emergence of the zone's brightly coloured homes, which have become a trademark of the neighborhood. The second section, Searching for Colours, details the composition of the paints made and used by La Boca residents, in addition to the field research, the method of analysis and the results of the study. The Conclusion highlights the importance of preserving areas of significant historical and patrimonial heritage such as La Boca, an ever more timely challenge in an increasingly globalized world. © 2010 Wiley Periodicals, Inc. Col Res Appl, 36, 222–228, 2011;     

Capacitance properties of electrochemically deposited polyazulene films

Polyazulene films formed by electrochemical oxidation of azulene have been studied as active components in electrochemical capacitors. The film shows reversible electrochemical behavior in the positive potential range and exhibits p-doping properties. The influence of film formation conditions on the films electrochemical properties has been investigated. A strong effect of solvent on the polyazulene deposition has been observed. The highest yield of film deposition was found for dichloromethane. Polyazulene films also exhibit stable voltammetric properties in aprotic solvents. The voltammetric response of the film is affected by the size of the anion of the supporting electrolyte. In solutions containing tetra(alkyl)ammonium perchlorates, tetrafluoroborates or hexafluorophosphates, reversible oxidation of polyazulene is obtained. In the presence of large tetra(phenyl)borate anions, polyazulene is irreversibly oxidized upon electrochemical oxidation. The capacitance properties of these materials have been investigated by cyclic voltammetry and electrochemical impedance spectroscopy. The polyazulene film displays a relatively high specific capacitance close to 400 F g⁻¹. Such high value of C_s locates this material among very good polymeric redox pseudo-capacitors.     

Mechanism of swift chemical sputtering: Comparison of Be/C/W dimer bond breaking

Current and future tokamak-like fusion reactors include the three elements Be, C, and W as the plasma-facing materials. During reactor operation, also mixtures of all these elements will form. Hence it is important to understand the atom-level mechanisms of physical and chemical sputtering in these materials. We have previously shown that athermal low-energy sputtering of pure C and Be can be understood by the swift chemical sputtering mechanism, where an incoming H (or D or T) ion enters between two atoms and pushes them apart. In the current article, we examine the model system of D impacting on a single dimer to determine the detailed mechanism of bond breaking and its probability for the Be₂, C₂, W₂, WC, BeW, and BeC dimers. The results are found to correlate well with recent experiments and simulations of sputtering of the corresponding bulk materials during prolonged H isotope bombardment.