We report here on the genome sequence of Pasteurella multocida Razi 0002 of avian origin, isolated in Iran. The genome has a size of 2,289,036 bp, a GC content of 40.3%, and is predicted to contain 2,079 coding sequences.

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Optical nanostructures have enabled the creation of subdiffraction detection volumes for single-molecule fluorescence microscopy. Their applicability is extended by the ability to place molecules in the confined observation volume without interfering with their biological function. Here, we demonstrate that processive DNA synthesis thousands of bases in length was carried out by individual DNA polymerase molecules immobilized in the observation volumes of zero-mode waveguides (ZMWs) in high-density arrays. Selective immobilization of polymerase to the fused silica floor of the ZMW was achieved by passivation of the metal cladding surface using polyphosphonate chemistry, producing enzyme density contrasts of glass over aluminum in excess of 400:1. Yields of single-molecule occupancies of Ϸ30% were obtained for a range of ZMW diameters (70 -100 nm). Results presented here support the application of immobilized single DNA polymerases in ZMW arrays for long-read-length DNA sequencing.fluorescence ͉ metal passivation ͉ microscopy ͉ polyvinyl phosphonic acid ͉ single molecule N anofabrication techniques have enabled new approaches to interrogate individual biomolecules by fluorescence techniques (reviewed in refs. 1 and 2). The extremely small size scale of the associated devices results in a drastic illumination volume reduction, allowing single-molecule investigations to take place at fluorophore concentrations increased to biologically relevant levels. In addition to higher temporal resolution and higher signal-to-noise ratios, they also provide spatial resolution beyond diffraction-limited optics.The zero-mode waveguide (ZMW) is one such nanophotonic confinement structure often consisting of a circular hole in a metal cladding film on a solid transparent substrate (3). In conjunction with laser-excited fluorescence, they provide observation volumes on the order of zeptoliters (10 Ϫ21 l), three to four orders of magnitude smaller than far-field excitation volumes. Applications of circular ZMWs have included the detection of single-molecule DNA polymerase activity by using labeled nucleotides at micromolar concentrations (3), the study of -repressor oligomerization dynamics (4), two-color crosscorrelation to rapidly screen for DNA restriction enzyme activity (5), and diffusion analysis of labeled membrane proteins in lipid bilayers of model membranes and living cells (6-11). C-shaped apertures have been described to study DNA hybridization interactions (12).ZMW technology applications have been limited by the unavailability of selective immobilization methods to position molecules exclusively in the observation volume, immediately above the transparent ZMW floor. One approach to selective immobilization exploits a feature inherent in the ZMW architecture. The transparent substrate and metal cladding are made of different materials, opening the possibility for a selective derivatization that will direct protein adsorption to the floor and not to the nearby metal walls. The nanometer size scale and three-dimensional n...

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Abstract:The addition of chromium and molybdenum to nickel creates alloys with exceptional corrosion resistance in a diverse range of environments. This study examines the complementary roles of Cr and Mo in Ni alloy passivation. Four nickel alloys with varying amounts of chromium and molybdenum were studied in 1 molar salt solutions over a broad pH range. The passive corrosion and breakdown behavior of the alloys suggests that chromium is the primary element influencing general corrosion resistance.The breakdown potential was nearly independent of molybdenum content, while the repassivation potential is strongly dependant on the molybdenum content. This indicates that chromium plays a strong role in maintaining the passivity of the alloy, while molybdenum acts to stabilize the passive film after a localized breakdown event.

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This richly illustrated and clearly written undergraduate textbook captures the excitement and beauty of geometry. The approach is that of Klein in his Erlangen programme: a geometry is a space together with a set of transformations of the space. The authors explore various geometries: affine, projective, inversive, hyperbolic and elliptic. In each case they carefully explain the key results and discuss the relationships between the geometries. New features in this second edition include concise end-of-chapter summaries to aid student revision, a list of further reading and a list of special symbols. The authors have also revised many of the end-of-chapter exercises to make them more challenging and to include some interesting new results. Full solutions to the 200 problems are included in the text, while complete solutions to all of the end-of-chapter exercises are available in a new Instructors' Manual, which can be downloaded from www.cambridge.org/9781107647831.

We introduce an acid addition technique for the rapid assessment of the influence of solution pH, anion ͑such as chloride͒ concentration, and temperature on the dissolution of metals. We demonstrate the technique with the characterization of the dissolution of alloy 22 ͑Ni-22Cr-13Mo-3W-3Fe͒ exposed to chloride-containing hydrochloric, sulfuric, and nitric acid environments as a function of pH ͑from pH 5 to pH −1͒ and temperature ͑25-90°C͒. A combination of electrochemical techniques ͑electrochemical impedance spectroscopy and linear polarization resistance͒ and atomic force microscopy are used to characterize the influence of the various solutions on the dissolution of alloy 22. Below 50°C, corrosion rates are less than 1 m/yr independent of acid type, pH, and temperature. In contrast, between 50°C and the upper explored limit of 90°C, dissolution rates in sulfuric and hydrochloric acid scale approximately linearly with temperature at rates that depend on the solution pH. In nitric acid, corrosion rates are lower at comparable pH values due to the oxidizing effects of nitrates. An increase in the open-circuit potential in conjunction with electrochemical impedance spectroscopy data suggests that nitrates promote a stable passive oxide film that inhibits alloy dissolution in all environments tested.Nickel-based alloys are employed in a wide range of applications where long lifetimes are vital such as in implant materials and nuclear waste storage. The robustness of alloys in these types of environments is due to the formation of a protective "passive" oxide film at the alloy interface. The nature and composition of these oxide films depends on the alloy composition and the pH, temperature, and electrolyte composition of the formation environment. Alloys can be tailored to fit a specific set of environmental conditions by selection of constituent elements that have strengths that compensate in the areas where other elements fail. For example, for Ni-Cr-Mo alloys, it is generally well established that the Mo provides resistance against reducing acidic environments, Cr against oxidizing conditions, Cr and Mo against localized attack, and Ni, Cr, and Mo against stress corrosion cracking due to chloride ions. [1][2][3][4] This combination of corrosion resistance in both reducing and oxidizing environments makes these alloys particularly well suited as long-term storage materials. As a result, the Ni-Cr-Mo alloy, alloy 22 ͑Ni-Cr22-Mo13-W3-Fe3͒, is the candidate material for the outer wall of nuclear waste packages at the proposed Yucca Mountain nuclear waste repository ͑Nevada, USA͒. Over the past decade, a number of studies have been undertaken to characterize its general and localized corrosion properties. 5-8 These studies demonstrate that alloy 22 is exceptionally corrosion resistant in a broad range of concentrated brines including chloride, fluoride, carbonate, sodium, and calcium with pH values ranging from ϳ2.7 to 13 and temperatures from 25 to 120°C. 9 To date, little work has been done to characterize the allo...