A builder and his family, 1898-1948; being the historical account of the contracting, engineering & construction career of W. A. Bechtel, and of how his sons and their associates have carried forward his principles in their many activities;

Reprint of the 1949 edition, with a new preface 1961.

Stimulation of MMP-11 (stromelysin-3) expression in mouse fibroblasts by cytokines, collagen and co-culture with human breast cancer cell lines

Background Matrix metalloproteinases (MMPs) are central to degradation of the extracellular matrix and basement membrane during both normal and carcinogenic tissue remodeling. MT1-MMP (MMP-14) and stromelysin-3 (MMP-11) are two members of the MMP family of proteolytic enzymes that have been specifically implicated in breast cancer progression. Expressed in stromal fibroblasts adjacent to epithelial tumour cells, the mechanism of MT1-MMP and MMP-11 induction remains unknown. Methods To investigate possible mechanisms of induction, we examined the effects of a number of plausible regulatory agents and treatments that may physiologically influence MMP expression during tumour progression. Thus NIH3T3 and primary mouse embryonic fibroblasts (MEFs) were: a) treated with the cytokines IL-1β, IL-2, IL-6, IL-8 and TGF-β for 3, 6, 12, 24, and 48 hours; b) grown on collagens I, IV and V; c) treated with fibronectin, con-A and matrigel; and d) co-cultured with a range of HBC (human breast cancer) cell lines of varied invasive and metastatic potential. Results Competitive quantitative RT-PCR indicated that MMP-11 expression was stimulated to a level greater than 100%, by 48 hour treatments of IL-1β, IL-2, TGF-β, fibronectin and collagen V. No other substantial changes in expression of MMP-11 or MT1-MMP in either tested fibroblast culture, under any treatment conditions, were observed. Conclusion We have demonstrated significant MMP-11 stimulation in mouse fibroblasts using cytokines, matrix constituents and HBC cell lines, and also some inhibition of MT1-MMP. Our data suggest that the regulation of these genes in the complex stromal-epithelial interactions that occur in human breast carcinoma, is influenced by several mechanisms.

Interdiffusion and Growth of the Phases in CoNi/Mo and CoNi/W Systems

Deleterious topological-closed-packed (tcp) phases grow in the interdiffusion zone in turbine blades mainly because of the addition of refractory elements such as Mo and W in the Ni- and Co-based superalloys. CoNi/Mo and CoNi/W diffusion couples are prepared to understand the growth mechanism of the phases in the interdiffusion zone. Instead of determining the main and cross-interdiffusion coefficients following the conventional method, we preferred to determine the average effective interdiffusion coefficients of two elements after fixing the composition of one element more or less the same in the interdiffusion zone. These parameters can be directly related to the growth kinetics of the phases and shed light on the atomic mechanism of diffusion. In both systems, the diffusion rate of elements and the phase layer thickness increased because of the addition of Ni in the solid solution phase, probably because of an increase in driving force. On the other hand, the growth rate of the mu phase and the diffusion coefficient of the species decreased because of the addition of Ni. This indicates the change in defect concentration, which assists diffusion. Further, we revisited the previously published Co-Ni-Mo and Co-Ni-W ternary phase diagrams and compared them with the composition range of the phases developed in the interdiffusion zone. Different composition ranges of the tcp phases are found, and corrected phase diagrams are shown. The outcome of this study will help to optimize the concentration of elements in superalloys to control the growth of the tcp phases.

Multi-scale modelling of Suzuki segregation in gamma' precipitates in Ni and Co-base superalloys

The high temperature strength of alloys with (gamma +gamma') microstructure is primarily due to the resistance of the ordered precipitate to cutting by matrix dislocations. Such shearing requires higher stresses since it involves the creation of a planar fault. Planar fault energy is known to be dependent on composition. This implies that the composition on the fault may be different from that in the bulk for energetic reasons. Such segregation (or desegregation) of specific alloying elements to the fault may result in Suzuki strengthening which has not been explored extensively in these systems. In this work, segregation (or desegregation) of alloying elements to planar faults was studied computationally in Ni-3(Al, Ti) and Co-3(W, Al) type gamma' precipitates. The composition dependence of APB energy and heat of mixing were evaluated from first principle electronic structure calculations. A phase field model incorporating the first principles results, was used to simulate the motion of an extended superdislocation under stress concurrently with composition evolution. Results reveal that in both systems, significant (de) segregation occurs on equilibration. On application of stress, solutes were dragged along with the APB in some cases. Additionally, it was also noted the velocity of the superdislocation under an applied stress is strongly dependent on atomic mobility (i. e. diffusivity).

Novel chemical synthesis of Pt-Ru-P electrocatalysts by hypophosphite deposition for enhanced methanol oxidation and CO tolerance in direct methanol fuel cell

A novel method was developed to prepare the highly active Pt-Ru-P/C catalyst. The deposition of phosphorus significantly increased electrochemical active surface (EAS) area of catalyst by reduces Pt-Ru particle size. TEM images show that Pt-Ru-P nanoparticles have an uniform size distribution with an average diameter of 2 nm. Cyclic voltammetry (CV), Chronoamperometry (CA), and CO stripping indicate that the presence of non-metal phosphorus as an interstitial species Pt-Ru-P/C catalyst shows high activity for the electro-oxidation of methanol, and exhibit enhanced performance in the oxidation of carbon monoxide compared with Pt-Ru/C catalyst. At 30 degrees C and pure oxygen was fed to the cathode, the maximum power density of direct methanol fuel cell (DMFC) with Pt-Ru-P/C and Pt-Ru/C catalysts as anode catalysts was 61.5 mW cm(-2) and 36.6 mW cm(-2), respectively. All experimental results indicate that Pt-Ru-P/C catalyst was the optimum anode catalyst for direct methanol fuel cell.

1,1 '-di(tert-butyl)metallocenium cations. The x-ray crystal structures of [M((C5H4Bu)-Bu-t)(2)]PF6 (M = Fe, Co) and [Co((C5H4Bu)-Bu-t)(2)](2)CoCl4

The hexafluorophosphate salts [Fe((C5H4Bu)-Bu-t)(2)]PF6 (1) and [Co((C5H4Bu)-Bu-t)(2)]PF6 (2) crystallize in isotypic structures with centrosymmetric cations which have a staggered (transoid) conformation of the exactly parallel ring Ligands (conformational angle tau = 180 degrees). The tetrachlorocobaltate salt, [CO((C5H4Bu)-Bu-t)(2)](2)CoCl4 (3), contains one almost eclipsed (tau = 140.4 degrees) and one almost staggered (tau = 101.4 degrees) cobaltocenium cation; in both cases, the cyclopentadienyl ring planes are slightly inclined (by alpha = 5.4 degrees and 4.1 degrees, respectively) to give more room to the tert-butyl substituents which are bent away from the metal in all three complexes 1 - 3.

Autonomia w nauce języka obcego – co osiągnęliśmy i dokąd zmierzamy?

Niniejszy tom poświęcony jest niezwykle istotnemu zagadnieniu w dydaktyce języków obcych, jakim jest autonomia, rozumiana nie tylko jako zdolność i chęć uczniów do przejęcia choćby części odpowiedzialności za własną naukę, ale również jako gotowość nauczycieli do wyjścia poza ramy instytucjonalne i stworzenia warunków, w których postawy i zachowania o charakterze autonomicznym mogą być rozwijane. Książka stanowi zbiór artykułów opartych na wybranych referatach wygłoszonych podczas konferencji pod hasłem Autonomia ucznia w nauczaniu języków obcych – co osiągnęliśmy i dokąd zmierzamy, zorganizowanej w maju 2007 roku przez Instytut Neofilologii Państwowej Wyższej Szkoły Zawodowej w Koninie oraz Zakład Filologii Angielskiej Wydziału Pedagogiczno-Artystycznego UAM w Kaliszu. Można ją również uznać za kontynuację rozważań nad autonomią zawartych w publikacji z 2004 roku, zatytułowanej Autonomia w nauce języka obcego i będącej pokłosiem pierwszej konferencji poświęconej tej właśnie tematyce.

Combined studies of DFT atomistic modelling and in situ FTIR spectroscopy on surface oxidants and CO oxidation at Ru electrodes

We report the combined studies of density functional theory (DFT) calculations and electrochemical in situ FTIR spectroscopy on surface oxidants and mechanisms of CO oxidation at the Ru(0001) electrodes. It is shown that CO can co-adsorb with both O and OH species at lower potential region where a low coverage of the (2 x 2)-O/OH adlayer formed; the oxidation of CO adsorbates takes place at higher potentials where a high coverage of the (1 x 1)-O/OH adlayer formed. Surface O species are not the active oxidants under all coverages studied, due to the high reaction barriers between CO and O (>1 eV). However, surface OH species with higher coverage are identified as the active oxidants, and CO oxidation takes place via a two-steps' mechanism of CO + 3OH -> COOH + 2OH -> CO2 + H2O + OH, in which three nearby OH species are involved in the CO2 formation: CO reacts with OH, forming COOH; COOH then transfers the H to a nearby OH to form H2O and CO2, at the same time, another H in the H2O transfers to a nearby OH to form a weak adsorbed H2O and a new OH. The reaction barrier of these processes is reduced significantly to around 0.50 eV. These new results not only provide an insight into surface active oxidants on Ru, which is directly relevant to fuel cell catalysis, but also reveals the extra complexity of catalytic reactions taking place at solid/liquid electrochemical interface in comparison to the relatively simpler ones at solid/gas phase. 

Measurements of stratospheric ozone at a mid-latitude observing station Valentia, Ireland (51.94° N, 10.25° W), using ground-based and ozonesonde observations from 1994 to 2009

Sixteen years (1994 – 2009) of ozone profiling by ozonesondes at Valentia Meteorological and Geophysical Observatory, Ireland (51.94° N, 10.23° W) along with a co-located MkIV Brewer spectrophotometer for the period 1993–2009 are analyzed. Simple and multiple linear regression methods are used to infer the recent trend, if any, in stratospheric column ozone over the station. The decadal trend from 1994 to 2010 is also calculated from the monthly mean data of Brewer and column ozone data derived from satellite observations. Both of these show a 1.5 % increase per decade during this period with an uncertainty of about ±0.25 %. Monthly mean data for March show a much stronger trend of ~ 4.8 % increase per decade for both ozonesonde and Brewer data. The ozone profile is divided between three vertical slots of 0–15 km, 15–26 km, and 26 km to the top of the atmosphere and a 11-year running average is calculated. Ozone values for the month of March only are observed to increase at each level with a maximum change of +9.2 ± 3.2 % per decade (between years 1994 and 2009) being observed in the vertical region from 15 to 26 km. In the tropospheric region from 0 to 15 km, the trend is positive but with a poor statistical significance. However, for the top level of above 26 km the trend is significantly positive at about 4 % per decade. The March integrated ozonesonde column ozone during this period is found to increase at a rate of ~6.6 % per decade compared with the Brewer and satellite positive trends of ~5 % per decade.

Simultaneous and Direct Determination of As, Bi, Pb, Sb, and Se and Co, Cr, Cu, Fe, and Mn in Milk by Electrothermal Atomic Absorption Spectrometry

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)