In the title compound, the Sr-N distances are 2.624 (3) and 2.676 (3) Angstroms. The Sr-centroid distances are 2.571 and 2.561 Angstroms. The N-C-C-N torsion angle in the bipyridine ligand is 2.2 (4){sup o}. Interestingly, the bipyridine ligand is tilted. The angle between the plane defined by Sr1, N1 and N2 and the plane defined by the 12 atoms of the bipyridine ligand is 10.7{sup o}.

There is a growing interest in Near Infra-Red (NIR) emission originating from organic complexes of Ln{sup III} cations. As a major impetus, biological tissues are considerably more transparent at these low energy wavelengths when compared to visible radiation, which facilitates deeper penetration of incident and emitted light. Furthermore, the long luminescence lifetimes of Ln{sup III} complexes (eg. Yb{sup III}, {tau}{sub rad} {approx} 1 ms) when compared to typical organic molecules can be utilized to vastly improve signal to noise ratios by employing time-gating techniques. While the improved quantum yield of Yb{sub III} complexes when compared to other NIR emitters favors their use for bioimaging applications, there has also been significant interest in the sensitized emission from other 4f metals such as Ln = Nd, Ho, Pr and Er which have well recognized applications as solid state laser materials (eg. Nd {approx} 1.06 {micro}m, Ho {approx} 2.09 {micro}m), and in telecommunications (eg. Er {approx} 1.54 {micro}m) where they can be used for amplification of optical signals. As a result of their weak (Laporte forbidden) f-f absorptions, the direct excitation of Ln{sup III} cations is inefficient, and sensitization of the metal emission is more effectively achieved using the so-called antenna effect. We …

We present a 3-dimensional model of supernova remnants (SNRs) where the hydrodynamical evolution of the remnant is modeled consistently with nonlinear diffusive shock acceleration occurring at the outer blast wave. The model includes particle escape and diffusion outside of the forward shock, and particle interactions with arbitrary distributions of external ambient material, such as molecular clouds. We include synchrotron emission and cooling, bremsstrahlung radiation, neutral pion production, inverse-Compton (IC), and Coulomb energy-loss. Boardband spectra have been calculated for typical parameters including dense regions of gas external to a 1000 year old SNR. In this paper, we describe the details of our model but do not attempt a detailed fit to any specific remnant. We also do not include magnetic field amplification (MFA), even though this effect may be important in some young remnants. In this first presentation of the model we don't attempt a detailed fit to any specific remnant. Our aim is to develop a flexible platform, which can be generalized to include effects such as MFA, and which can be easily adapted to various SNR environments, including Type Ia SNRs, which explode in a constant density medium, and Type II SNRs, which explode in a pre-supernova wind. When …

The two-fluid description is a very successful phenomenological representation of the properties of Helium II. A 3-D model suitable for numerical analysis based on the Landau-Khalatnikov description of Helium II is proposed. In this paper we introduce a system of partial differential equations that is both complete and consistent as well as practical, to be used for a 3-D solution of the flow of Helium II. The development of a 3-D numerical model for Helium II is motivated by the need to validate experimental results obtained by observing the normal component velocity distribution in a Helium II thermal counter-flow using the Particle Image Velocimetry (PIV) technique.

A high contrast 12.6 keV Kr K{alpha} source has been demonstrated on the petawatt-class Titan laser facility. The contrast ratio (K{alpha} to continuum) is 65, with a competitive ultra short pulse laser to x-ray conversion efficiency of 10{sup -5}. Filtered shadowgraphy indicates that the Kr K{alpha} and K{beta} x-rays are emitted from a roughly 1 x 2 mm emission volume, making this source suitable for area backlighting and scattering. Spectral calculations indicate a typical bulk electron temperature of 50-70 eV (i.e. mean ionization state 13-16), based on the observed ratio of K{alpha} to K{beta}. Kr gas jets provide a debris-free high energy K{alpha} source for time-resolved diagnosis of dense matter.

One of the most important applications of the general purpose Monte Carlo N-Particle (MCNPS and MCNPX) codes is neutron shielding design. We employed this method to simulate the shield of a 14-MeV neutron generator used as a thermal neutron source providing an external thermal neutron beam for testing large area neutron detectors developed for diffraction studies in biology and also useful for national security applications. Nuclear reactors have been the main sources of neutrons used for scientific applications. In the past decade, however, a large number of reactors have been shut down, and the importance of other, smaller devices capable of providing neutrons for research has increased. At Brookhaven National Laboratory a moderated Am-Be neutron source with shielding is used for neutron detector testing. This source is relatively weak, but provides a constant flux of neutrons, even when not in use. The use of a 14 MeV energized neutron generator, with an order of magnitude higher neutron flux has been considered to replace the Am-Be source, but the higher fast neutron yield requires a more careful design of moderator and shielding. In the present paper we describe a proposed shielding configuration based on Monte Carlo calculations, and provide calculated neutron …

The MERIT experiment, which ran at CERN in 2007, is a proof-of-principle test for a target system that converts a 4-MW proton beam into a high-intensity muon beam for either a neutrino factory complex or a muon collider. The target system is based on a free mercury jet that intercepts an intense proton beam inside a 15-T solenoidal magnetic field. Here, we describe the design and performance of the 15-T, liquid-nitrogen-precooled, copper solenoid magnet.

Over forty years, there have been major efforts to aim at understanding the properties of surfaces, structure, composition, dynamics on the molecular level and at developing the surface science of heterogeneous and homogeneous catalysis. Since most catalysts (heterogeneous, enzyme and homogeneous) are nanoparticles, colloid synthesis methods were developed to produce monodispersed metal nanoparticles in the 1-10 nm range and controlled shapes to use them as new model catalyst systems in two-dimensional thin film form or deposited in mezoporous three-dimensional oxides. Studies of reaction selectivity in multipath reactions (hydrogenation of benzene, cyclohexene and crotonaldehyde) showed that reaction selectivity depends on both nanoparticle size and shape. The oxide-metal nanoparticle interface was found to be an important catalytic site because of the hot electron flow induced by exothermic reactions like carbon monoxide oxidation.

The Archaea are a fascinating and diverse group of prokaryotic organisms with deep roots overlapping those of eukaryotes. The focus of this GRC conference, 'Archaea: Ecology Metabolism & Molecular Biology', expands on a number of emerging topics highlighting the evolution and composition of microbial communities and novel archaeal species, their impact on the environment, archaeal metabolism, and research that stems from sequence analysis of archaeal genomes. The strength of this conference lies in its ability to couple reputable areas with new scientific topics in an atmosphere of stimulating exchange. This conference remains an excellent opportunity for younger scientists to interact with world experts in this field.

Cellulose, a key component of the plant cell wall, comprises the most abundant source of organic carbon on the planet and its microbial degradation is of considerable biological and industrial importance. Indeed, the microbial degradation of cellulose and other plant structural polysaccharides is critical to the maintenance of the carbon cycle in terrestrial and marine microbial ecosystems, host invasion by several phytopathogens, and herbivore nutrition. While the enzymes that attack cellulose are already widely used in several biotechnology-based industries, the major future application of these biocatalysts is the conversion of plant biomass into bio-ethanol and other forms of energy. In that context, the 2007 Conference will present the latest breakthroughs in our understanding of the enzymology, structural biology and (meta)genomics underpinning the conversion of plant structural polysaccharides into fermentable sugars, both in natural and engineered processes. There is also an increased emphasis on the roles of other carbohydrate active enzymes in plant biomass conversion. The themes for the scientific sessions include: (1) crystallographic and biochemical analyses of enzyme structure and function; (2) molecular mechanisms underpinning enzyme catalysis, processivity and specificity; (3) functional and comparative analyses of carbohydrate binding modules and enzyme-substrate interactions; (4) directed evolution for the development of catalytically …

This conference focuses on kinetic, mechanistic, and thermodynamic studies of reactions that play a role in fields as diverse as catalysis, energy, bioinorganic chemistry, green chemistry, organometallics, and activation of small molecules (oxygen, nitrogen, carbon monoxide, carbon dioxide, alkanes). Participants from universities, industry, and national laboratories present results and engage in discussions of pathways, intermediates, and outcome of various reactions of inorganic, organic, coordination, organometallic, and biological species. This knowledge is essential for rational development and design of novel reactions, compounds, and catalysts.

Microbial Population Biology covers a diverse range of cutting edge issues in the microbial sciences and beyond. Firmly founded in evolutionary biology and with a strongly integrative approach, past meetings have covered topics ranging from the dynamics and genetics of adaptation to the evolution of mutation rate, community ecology, evolutionary genomics, altruism, and epidemiology. This meeting is never dull: some of the most significant and contentious issues in biology have been thrashed out here. We anticipate the 2007 meeting being no exception. The final form of the 2007 meeting is yet to be decided, but the following topics are likely to be included: evolutionary emergence of infectious disease and antibiotic resistance, genetic architecture and implications for the evolution of microbial populations, ageing in bacteria, biogeography, evolution of symbioses, the role of microbes in ecosystem function, and ecological genomics.

This Report describes Molecular & Cellular Bioenergetics.

The results of a review and evaluation of neutron and non-neutron nuclear data published in the scientific literature are presented. The status of new chemical elements is examined. Data on revised values for the isotopic composition of the elements are reviewed and recommended values are presented. Half-lives of very long-lived nuclides are presented, including double beta decay, double electron capture, long-lived alpha decay and long-lived beta decay. Data from new measurements on the very heavy elements (trans-meitnerium elements) are discussed and tabulated. The first observation of the radioactive decay mode of the free neutron is discussed. New measurements that have expanded the neutron drip line for magnesium and aluminum are discussed. Data on recent neutron cross-section and resonance integral measurements are also discussed.

Plant Metabolic Engineering is an emerging field that integrates a diverse range of disciplines including plant genetics, genomics, biochemistry, chemistry and cell biology. The Gordon-Kenan Graduate Research Seminar (GRS) in Plant Metabolic Engineering was initiated to provide a unique opportunity for future researcher leaders to present their work in this field. It also creates an environment allowing for peer-review and critical assessment of work without the intimidation usually associated with the presence of senior investigators. The GRS immediately precedes the Plant Metabolic Engineering Gordon Research Conference and will be for and by graduate students and post-docs, with the assistance of the organizers listed.

The theme of the fifth Gordon Research Conference on Radiation and Climate is 'Integrating multiscale measurements and models for key climate questions'. The meeting will feature lectures, posters, and discussion regarding these issues. The meeting will focus on insights from new types of satellite and in situ data and from new approaches to modeling processes in the climate system. The program on measurements will highlight syntheses of new satellite data on cloud, aerosols, and chemistry and syntheses of satellite and sub-orbital observations from field programs. The program on modeling will address both the evaluation of cloud-resolving and regional aerosol models using new types of measurements and the evidence for processes and physics missing from global models. The Conference will focus on two key climate questions. First, what factors govern the radiative interactions of clouds and aerosols with regional and global climate? Second, how well do we understand the interaction of radiation with land surfaces and with the cryosphere?

This Gordon Research Conference seeks to brings together chemists, physicists, materials scientists and biologists to address perhaps the outstanding technical problem of the 21st Century - the efficient, and ultimately economical, storage of energy from carbon-neutral sources. Such an advance would deliver a renewable, environmentally benign energy source for the future. A great technological challenge facing our global future is energy. The generation of energy, the security of its supply, and the environmental consequences of its use are among the world's foremost geopolitical concerns. Fossil fuels - coal, natural gas, and petroleum - supply approximately 90% of the energy consumed today by industrialized nations. An increase in energy supply is vitally needed to bring electric power to the 25% of the world's population that lacks it, to support the industrialization of developing nations, and to sustain economic growth in developed countries. On the geopolitical front, insuring an adequate energy supply is a major security issue for the world, and its importance will grow in proportion to the singular dependence on oil as a primary energy source. Yet, the current approach to energy supply, that of increased fossil fuel exploration coupled with energy conservation, is not scaleable to meet future demands. …

Time-dependent density-functional theory (TDDFT) provides an efficient, elegant, and formally exact way of describing the dynamics of interacting many-body quantum systems, circumventing the need for solving the full time-dependent Schroedinger equation. In the 20 years since it was first rigorously established in 1984, the field of TDDFT has made rapid and significant advances both formally as well as in terms of successful applications in chemistry, physics and materials science. Today, TDDFT has become the method of choice for calculating excitation energies of complex molecules, and is becoming increasingly popular for describing optical and spectroscopic properties of a variety of materials such as bulk solids, clusters and nanostructures. Other growing areas of applications of TDDFT are nonlinear dynamics of strongly excited electronic systems and molecular electronics. The purpose and scope of this Gordon Research Conference is to provide a platform for discussing the current state of the art of the rapidly progressing, highly interdisciplinary field of TDDFT, to identify and debate open questions, and to point out new promising research directions. The conference will bring together experts with a diverse background in chemistry, physics, and materials science.

A new benchmarking concept is presented for verifying the PEBBED 3D multigroup finite difference/nodal diffusion code with application to pebble bed modular reactors (PBMRs). The key idea is to perform convergence acceleration, also called extrapolation to zero discretization, of a basic finite difference numerical algorithm to give extremely high accuracy. The method is first demonstrated on a 1D cylindrical shell and then on an r,8 wedge where the order of the second order finite difference scheme is confirmed to four places.

A three-dimensional computational fluid dynamics (CFD) electrochemical model has been created to model high-temperature electrolysis cell performance and steam electrolysis in a new novel integrated planar porous-tube supported solid oxide electrolysis cell (SOEC). The model is of several integrated planar cells attached to a ceramic support tube. This design is being evaluated with modeling at the Idaho National Laboratory. Mass, momentum, energy, and species conservation and transport are provided via the core features of the commercial CFD code FLUENT. A solid-oxide fuel cell (SOFC) model adds the electrochemical reactions and loss mechanisms and computation of the electric field throughout the cell. The FLUENT SOFC user-defined subroutine was modified for this work to allow for operation in the SOEC mode. Model results provide detailed profiles of temperature, Nernst potential, operating potential, activation over-potential, anode-side gas composition, cathode-side gas composition, current density and hydrogen production over a range of stack operating conditions. Mean per-cell area-specific-resistance (ASR) values decrease with increasing current density. Predicted mean outlet hydrogen and steam concentrations vary linearly with current density, as expected. Effects of variations in operating temperature, gas flow rate, cathode and anode exchange current density, and contact resistance from the base case are presented. Contour plots …

The concepts and technical challenges related to developing a 4th generation ECR ion source with an RF frequency greater than 40 GHz and magnetic confinement fields greater than twice Becr will be explored in this paper. Based on the semi-empirical frequency scaling of ECR plasma density with the square of operating frequency, there should be significant gains in performance over current 3rd generation ECR ion sources, which operate at RF frequencies between 20 and 30 GHz. While the 3rd generation ECR ion sources use NbTi superconducting solenoid and sextupole coils, the new sources will need to use different superconducting materials such as Nb3Sn to reach the required magnetic confinement, which scales linearly with RF frequency. Additional technical challenges include increased bremsstrahlung production, which may increase faster than the plasma density, bremsstrahlung heating of the cold mass and the availability of high power continuous wave microwave sources at these frequencies. With each generation of ECR ion sources, there are new challenges to be mastered, but the potential for higher performance and reduced cost of the associated accelerator continue to make this a promising avenue for development.

Systems biology recognizes the complex multi-scale organization of biological systems, from molecules to ecosystems. The International Symposium on Systems Biology has been hosted by the Institute for Systems Biology in Seattle, Washington, since 2002. The annual two-day event gathers the most influential researchers transforming biology into an integrative discipline investingating complex systems. Engineering and application of new technology is a central element of systems biology. Genome-scale, or very small-scale, biological questions drive the enigneering of new technologies, which enable new modes of experimentation and computational analysis, leading to new biological insights and questions. Concepts and analytical methods in engineering are now finding direct applications in biology. Therefore, the 2008 Symposium, funded in partnership with the Department of Energy, featured global leaders in "Systems Biology and Engineering."

We develop a new ab initio many-body approach capable of describing simultaneously both bound and scattering states in light nuclei, by combining the resonating-group method with the use of realistic interactions, and a microscopic and consistent description of the nucleon clusters. This approach preserves translational symmetry and Pauli principle. We present phase shifts for neutron scattering on {sup 3}H, {sup 4}He and {sup 10}Be and proton scattering on {sup 3,4}He, using realistic nucleon-nucleon potentials. Our A = 4 scattering results are compared to earlier ab initio calculations. We demonstrate that a proper treatment of the coupling to the n-{sup 10}Be continuum is essential to explain the parity-inverted ground state in {sup 11}Be.

Article on the ab initio solubility prediction of non-electrolytes in ternary solvents using a combination of Jouyban-Acree and Abraham models.