Molecules in motion: influences of diffusion on metabolic structure and function in skeletal muscle.

PubMed

Kinsey, Stephen T; Locke, Bruce R; Dillaman, Richard M

2011-01-15

Metabolic processes are often represented as a group of metabolites that interact through enzymatic reactions, thus forming a network of linked biochemical pathways. Implicit in this view is that diffusion of metabolites to and from enzymes is very fast compared with reaction rates, and metabolic fluxes are therefore almost exclusively dictated by catalytic properties. However, diffusion may exert greater control over the rates of reactions through: (1) an increase in reaction rates; (2) an increase in diffusion distances; or (3) a decrease in the relevant diffusion coefficients. It is therefore not surprising that skeletal muscle fibers have long been the focus of reaction-diffusion analyses because they have high and variable rates of ATP turnover, long diffusion distances, and hindered metabolite diffusion due to an abundance of intracellular barriers. Examination of the diversity of skeletal muscle fiber designs found in animals provides insights into the role that diffusion plays in governing both rates of metabolic fluxes and cellular organization. Experimental measurements of metabolic fluxes, diffusion distances and diffusion coefficients, coupled with reaction-diffusion mathematical models in a range of muscle types has started to reveal some general principles guiding muscle structure and metabolic function. Foremost among these is that metabolic processes in muscles do, in fact, appear to be largely reaction controlled and are not greatly limited by diffusion. However, the influence of diffusion is apparent in patterns of fiber growth and metabolic organization that appear to result from selective pressure to maintain reaction control of metabolism in muscle.

Ionic Conduction in Lithium Ion Battery Composite Electrode Governs Cross-sectional Reaction Distribution.

PubMed

Orikasa, Yuki; Gogyo, Yuma; Yamashige, Hisao; Katayama, Misaki; Chen, Kezheng; Mori, Takuya; Yamamoto, Kentaro; Masese, Titus; Inada, Yasuhiro; Ohta, Toshiaki; Siroma, Zyun; Kato, Shiro; Kinoshita, Hajime; Arai, Hajime; Ogumi, Zempachi; Uchimoto, Yoshiharu

2016-05-19

Composite electrodes containing active materials, carbon and binder are widely used in lithium-ion batteries. Since the electrode reaction occurs preferentially in regions with lower resistance, reaction distribution can be happened within composite electrodes. We investigate the relationship between the reaction distribution with depth direction and electronic/ionic conductivity in composite electrodes with changing electrode porosities. Two dimensional X-ray absorption spectroscopy shows that the reaction distribution is happened in lower porosity electrodes. Our developed 6-probe method can measure electronic/ionic conductivity in composite electrodes. The ionic conductivity is decreased for lower porosity electrodes, which governs the reaction distribution of composite electrodes and their performances.

Distinct Structural Elements Govern the Folding, Stability, and Catalysis in the Outer Membrane Enzyme PagP.

PubMed

Iyer, Bharat Ramasubramanian; Mahalakshmi, Radhakrishnan

2016-09-06

The outer membrane enzyme PagP is indispensable for lipid A palmitoylation in Gram-negative bacteria and has been implicated in resistance to host immune defenses. PagP possesses an unusual structure for an integral membrane protein, with a highly dynamic barrel domain that is tilted with respect to the membrane normal. In addition, it contains an N-terminal amphipathic helix. Recent functional and structural studies have shown that these molecular factors are critical for PagP to carry out its function in the challenging environment of the bacterial outer membrane. However, the precise contributions of the N-helix to folding and stability and residues that can influence catalytic rates remain to be addressed. Here, we identify a sequence-dependent stabilizing role for the N-terminal helix of PagP in the measured thermodynamic stability of the barrel. Using chimeric barrel sequences, we show that the Escherichia coli PagP N-terminal helix confers 2-fold greater stability to the Salmonella typhimurium barrel. Further, we find that the W78F substitution in S. typhimurium causes a nearly 20-fold increase in the specific activity in vitro for the phospholipase reaction, compared to that of E. coli PagP. Here, phenylalanine serves as a key regulator of catalysis, possibly by increasing the reaction rate. Through coevolution analysis, we detect an interaction network between seemingly unrelated segments of this membrane protein. Exchanging the structural and functional features between homologous PagP enzymes from E. coli and S. typhimurium has provided us with an understanding of the molecular factors governing PagP stability and function.

A dual-process model of reactions to perceived stigma.

PubMed

Pryor, John B; Reeder, Glenn D; Yeadon, Christopher; Hesson-McLnnis, Matthew

2004-10-01

The authors propose a theoretical model of individual psychological reactions to perceived stigma. This model suggests that 2 psychological systems may be involved in reactions to stigma across a variety of social contexts. One system is primarily reflexive, or associative, whereas the other is rule based, or reflective. This model assumes a temporal pattern of reactions to the stigmatized, such that initial reactions are governed by the reflexive system, whereas subsequent reactions or "adjustments" are governed by the rule-based system. Support for this model was found in 2 studies. Both studies examined participants' moment-by-moment approach-avoidance reactions to the stigmatized. The 1st involved participants' reactions to persons with HIV/AIDS, and the 2nd, participants' reactions to 15 different stigmatizing conditions. (c) 2004 APA, all rights reserved

From bismuth oxide/hydroxide precursor clusters towards stable oxides: Proton transfer reactions and structural reorganization govern the stability of [Bi18O13(OH)10]-nitrate clusters

NASA Astrophysics Data System (ADS)

Walther, M.; Zahn, D.

2018-01-01

Structural relaxation and stability of a Bi18-cluster as obtained from association of [Bi6O4(OH)4](NO3)6 precursor clusters in DMSO solution is investigated from a combination of quantum chemical calculations and μs-scale molecular dynamics simulations using empirical interaction potentials. The Bi18-cluster undergoes a OH⋯OH proton transfer reaction, followed by considerable structural relaxation. While the aggregation of the Bi18-cluster is induced by the dissociation of a single nitrate ion leading to [Bi6O4(OH)4](NO3)5+ as an activated precursor species that can bind two more Bi6-clusters, we find the [Bi18O13(OH)10](NO3)18-x+x species (explored for x = 1-6) rather inert against either nitrate dissociation, collision with Bi6-precursors or combinations thereof.

Kinetically governed polymorphism of d(G₄T₄G₃) quadruplexes in K+ solutions.

PubMed

Prislan, Iztok; Lah, Jurij; Milanic, Matija; Vesnaver, Gorazd

2011-03-01

It has been generally recognized that understanding the molecular basis of some important cellular processes is hampered by the lack of knowledge of forces that drive spontaneous formation/disruption of G-quadruplex structures in guanine-rich DNA sequences. According to numerous biophysical and structural studies G-quadruplexes may occur in the presence of K(+) and Na(+) ions as polymorphic structures formed in kinetically governed processes. The reported kinetic models suggested to describe this polymorphism should be considered inappropriate since, as a rule, they include bimolecular single-step associations characterized by negative activation energies. In contrast, our approach in studying polymorphic behavior of G-quadruplexes is based on model mechanisms that involve only elementary folding/unfolding transitions and structural conversion steps that are characterized by positive activation energies. Here, we are investigating a complex polymorphism of d(G(4)T(4)G(3)) quadruplexes in K(+) solutions. On the basis of DSC, circular dichroism and UV spectroscopy and polyacrylamide gel electrophoresis experiments we propose a kinetic model that successfully describes the observed thermally induced conformational transitions of d(G(4)T(4)G(3)) quadruplexes in terms of single-step reactions that involve besides single strands also one tetramolecular and three bimolecular quadruplex structures.

Ionic Conduction in Lithium Ion Battery Composite Electrode Governs Cross-sectional Reaction Distribution

PubMed Central

Orikasa, Yuki; Gogyo, Yuma; Yamashige, Hisao; Katayama, Misaki; Chen, Kezheng; Mori, Takuya; Yamamoto, Kentaro; Masese, Titus; Inada, Yasuhiro; Ohta, Toshiaki; Siroma, Zyun; Kato, Shiro; Kinoshita, Hajime; Arai, Hajime; Ogumi, Zempachi; Uchimoto, Yoshiharu

2016-01-01

Composite electrodes containing active materials, carbon and binder are widely used in lithium-ion batteries. Since the electrode reaction occurs preferentially in regions with lower resistance, reaction distribution can be happened within composite electrodes. We investigate the relationship between the reaction distribution with depth direction and electronic/ionic conductivity in composite electrodes with changing electrode porosities. Two dimensional X-ray absorption spectroscopy shows that the reaction distribution is happened in lower porosity electrodes. Our developed 6-probe method can measure electronic/ionic conductivity in composite electrodes. The ionic conductivity is decreased for lower porosity electrodes, which governs the reaction distribution of composite electrodes and their performances. PMID:27193448

Shock-wave-like structures induced by an exothermic neutralization reaction in miscible fluids

NASA Astrophysics Data System (ADS)

Bratsun, Dmitry; Mizev, Alexey; Mosheva, Elena; Kostarev, Konstantin

2017-11-01

We report shock-wave-like structures that are strikingly different from previously observed fingering instabilities, which occur in a two-layer system of miscible fluids reacting by a second-order reaction A +B →S in a vertical Hele-Shaw cell. While the traditional analysis expects the occurrence of a diffusion-controlled convection, we show both experimentally and theoretically that the exothermic neutralization reaction can also trigger a wave with a perfectly planar front and nearly discontinuous change in density across the front. This wave propagates fast compared with the characteristic diffusion times and separates the motionless fluid and the area with anomalously intense convective mixing. We explain its mechanism and introduce a new dimensionless parameter, which allows to predict the appearance of such a pattern in other systems. Moreover, we show that our governing equations, taken in the inviscid limit, are formally analogous to well-known shallow-water equations and adiabatic gas flow equations. Based on this analogy, we define the critical velocity for the onset of the shock wave which is found to be in the perfect agreement with the experiments.

The underlying pathway structure of biochemical reaction networks

PubMed Central

Schilling, Christophe H.; Palsson, Bernhard O.

1998-01-01

Bioinformatics is yielding extensive, and in some cases complete, genetic and biochemical information about individual cell types and cellular processes, providing the composition of living cells and the molecular structure of its components. These components together perform integrated cellular functions that now need to be analyzed. In particular, the functional definition of biochemical pathways and their role in the context of the whole cell is lacking. In this study, we show how the mass balance constraints that govern the function of biochemical reaction networks lead to the translation of this problem into the realm of linear algebra. The functional capabilities of biochemical reaction networks, and thus the choices that cells can make, are reflected in the null space of their stoichiometric matrix. The null space is spanned by a finite number of basis vectors. We present an algorithm for the synthesis of a set of basis vectors for spanning the null space of the stoichiometric matrix, in which these basis vectors represent the underlying biochemical pathways that are fundamental to the corresponding biochemical reaction network. In other words, all possible flux distributions achievable by a defined set of biochemical reactions are represented by a linear combination of these basis pathways. These basis pathways thus represent the underlying pathway structure of the defined biochemical reaction network. This development is significant from a fundamental and conceptual standpoint because it yields a holistic definition of biochemical pathways in contrast to definitions that have arisen from the historical development of our knowledge about biochemical processes. Additionally, this new conceptual framework will be important in defining, characterizing, and studying biochemical pathways from the rapidly growing information on cellular function. PMID:9539712

Substituent-directed structural and physicochemical controls of diruthenium catecholate complexes with ligand-unsupported Ru-Ru bonds.

PubMed

Chang, Ho-Chol; Mochizuki, Katsunori; Kitagawa, Susumu

2005-05-30

A family of diruthenium complexes with ligand-unsupported Ru-Ru bonds has been systematically synthesized, and their crystal structures and physical properties have been examined. A simple, useful reaction between Ru2(OAc)4Cl (OAc- = acetate) and catechol derivatives in the presence of bases afforded a variety of diruthenium complexes, generally formulated as [Na(n){Ru2(R4Cat)4}] (n = 2 or 3; R4 = -F4, -Cl4, -Br4, -H4, -3,5-di-t-Bu, and -3,6-di-t-Bu; Cat(2-) = catecholate). The most characteristic feature of the complexes is the formation of short ligand-unsupported Ru-Ru bonds (2.140-2.273 A). These comprehensive studies were carried out to evaluate the effects of the oxidation states and the substituents governing the molecular structures and physicochemical properties. The Ru-Ru bond distances, rotational conformations, and bending structures of the complexes were successfully varied. The results presented in this manuscript clearly demonstrate that the complexes with ligand-unsupported Ru-Ru bonds can sensitively respond to redox reactions and ligand substituents on the basis of the greater degree of freedom in their molecular structures.

Nonequilibrium Self-Assembly of π-Conjugated Oligopeptides in Solution.

PubMed

Li, Bo; Li, Songsong; Zhou, Yuecheng; Ardoña, Herdeline Ann M; Valverde, Lawrence R; Wilson, William L; Tovar, John D; Schroeder, Charles M

2017-02-01

Supramolecular assembly is a powerful method that can be used to generate materials with well-defined structures across multiple length scales. Supramolecular assemblies consisting of biopolymer-synthetic polymer subunits are specifically known to exhibit exceptional structural and functional diversity as well as programmable control of noncovalent interactions through hydrogen bonding in biopolymer subunits. Despite recent progress, there is a need to control and quantitatively understand assembly under nonequilibrium conditions. In this work, we study the nonequilibrium self-assembly of π-conjugated synthetic oligopeptides using a combination of experiments and analytical modeling. By isolating an aqueous peptide solution droplet within an immiscible organic layer, the rate of peptide assembly in the aqueous solution can be controlled by tuning the transport rate of acid that is used to trigger assembly. Using this approach, peptides are guided to assemble under reaction-dominated and diffusion-dominated conditions, with results showing a transition from a diffusion-limited reaction front to spatially homogeneous assembly as the transport rate of acid decreases. Interestingly, our results show that the morphology of self-assembled peptide fibers is controlled by the assembly kinetics such that increasingly homogeneous structures of self-assembled synthetic oligopeptides were generally obtained using slower rates of assembly. We further developed an analytical reaction-diffusion model to describe oligopeptide assembly, and experimental results are compared to the reaction-diffusion model across a range of parameters. Overall, this work highlights the importance of molecular self-assembly under nonequilibrium conditions, specifically showing that oligopeptide assembly is governed by a delicate balance between reaction kinetics and transport processes.

Reaching to a featured formula to deduce the energy of the heaviest particles producing from the controlled thermonuclear fusion reactions

NASA Astrophysics Data System (ADS)

Majeed, Raad H.; Oudah, Osamah N.

2018-05-01

Thermonuclear fusion reaction plays an important role in developing and construction any power plant system. Studying the physical behavior for the possible mechanism governed energies released by the fusion products to precise understanding the related kinematics. In this work a theoretical formula controlled the general applied thermonuclear fusion reactions is achieved to calculating the fusion products energy depending upon the reactants physical properties and therefore, one can calculate other parameters governed a given reaction. By using this formula, the energy spectrum of 4He produced from T-3He fusion reaction has been sketched with respect to reaction angle and incident energy ranged from (0.08-0.6) MeV.

Nonlinear Tollmien-Schlichting/vortex interaction in boundary layers

NASA Technical Reports Server (NTRS)

Hall, P.; Smith, F. T.

1988-01-01

The nonlinear reaction between two oblique 3-D Tollmein-Schlichting (TS) waves and their induced streamwise-vortex flow is considered theoretically for an imcompressible boundary layer. The same theory applies to the destabilization of an incident vortex motion by subharmonic TS waves, followed by interaction. The scales and flow structure involved are addressed for high Reynolds numbers. The nonlionear interaction is powerful, starting at quite low amplitudes with a triple-deck structure for the TS waves but a large-scale structure for the induced vortex, after which strong nonlinear amplification occurs. This includes nonparallel-flow effects. The nonlinear interaction is governed by a partial differential system for the vortex flow coupled with an ordinary-differential one for the TS pressure. The solution properties found sometimes produce a breakup within a finite distance and sometimes further downstream, depending on the input amplitudes upstream and on the wave angles, and that then leads to the second stages of interaction associated with higher amplitudes, the main second stages giving either long-scale phenomena significantly affected by nonparallelism or shorter quasi-parallel ones governed by the full nonlinear triple-deck response.

A comparison of the physical and chemical processes governing the CO2 laser-induced pyrolysis and deflagration of XM39 and M43

NASA Astrophysics Data System (ADS)

Fetherolf, B. L.; Litzinger, T. A.; Lu, Y.-C.; Kuo, Kenneth K.

1993-11-01

The RDX-based composite propellants XM39 and M43 are similar in composition but exhibit significant differences in burning behavior. Experimental studies of the physical and chemical processes governing the CO2 laser-induced pyrolysis and deflagration of these two materials were conducted to characterize these differences in behavior and to gain some insight into the mechanisms responsible for the observed differences. Tests were conducted at one, three, and five atmospheres and laser heat fluxes of 100 - 1000 W/sq cm. Quantitative gaseous species profiles were measured with a microprobe/mass spectrometer system and both gas-phase temperature profiles and surface temperatures were measured with fine-wire thermocouples. Both materials exhibited similar gas-phase reaction chemistry to that of RDX with a primary nonluminous flame zone due to the reaction of CH2O and NO2 and a final luminous flame zone where HCN, NO, and a smaller amount of N2O were consumed to form the final products. However, the gas-phase zonal structure was significantly stretched out in comparison to the structure for pure RDX. The luminous flame was only observed above three atmospheres for M43 and above five atmospheres for XM39. Species and temperature measurements at the surfaces of the pyrolyzing propellants appeared to indicate more reaction in the condensed phase (i.e., melt layer) for M43 than for XM39. Subsurface gas species were measured by placing a probe within a hole drilled partway through a sample of XM39. The results indicated substantially less H2O, CH2O, HCN, and NO2 than were measured directly above the surface. This result and the observation of a temperature rise of about 100 degrees within the first 150 microns above the surface for both XM39 and M43 support the possible existence of a thin gas-phase reaction zone directly above the propellant surface.

Controllable synthesis of Co3O4 nanocrystals as efficient catalysts for oxygen reduction reaction

NASA Astrophysics Data System (ADS)

Li, Baoying; Zhang, Yihe; Du, Ruifeng; Liu, Lei; Yu, Xuelian

2018-03-01

The electrochemical oxygen reduction reaction (ORR) has received great attention due to its importance in fuel cells and metal-air batteries. Here, we present a simple approach to prepare non-noble metal catalyst-Co3O4 nanocrystals (NCs). The particle size and shape were simply controlled by different types and concentrations of metal precursor. Furthermore, different sizes and shapes of Co3O4 NCs are explored as electrocatalysts for ORR, and it has been observed that particles with a similar shape, and smaller particle size led to greater catalytic current densities because of the greater surface area. For particles with a comparable size, the shape or crystalline structure governed the activity of the electrocatalytic reactions. Most importantly, the 9 nm-Co3O4 were demonstrated to act as low-cost catalysts for the ORR with a similar performance to that of Pt catalysts.

A health system in economic crises: a case study from Iceland.

PubMed

Olafsdottir, Anna Elisabet; Allotey, Pascale; Reidpath, Daniel D

2013-03-01

There has been a lack of systematic inquiry into how governments respond during times of crises, how well these responses comply with good governance, and how they affect health systems. The aim of this study was to analyse the reactions of the Icelandic health system during the first 7 months of the economic crisis in 2008. The grounded theory approach was used in data sampling, collection, and data analysis. Secondary data were collected from parliamentary documents, news, and health discussions in two of the largest newspapers in Iceland. Primary data were collected through interviews with key stakeholders in the health sector. Atlas.ti. 5.2 was used to analyse the data. The health sector's first response to the crisis was to close and merge wards on hospitals as well as making structural changes to reduce the overhead costs in healthcare institutions. The Minister of Health attempted to introduce radical changes but because of failures in good governance practices, such as a lack of transparency and fair participation together with a lack of supporting documents, the proposed changes were not executed. Economic crises are a critical test of health systems' resilience. The manner in which governance practices, together with strong stewardship, influence the ability of the health system to adapt to changes and reorganise without causing stress, confusion, or anger and without changing its basic structure and function are important, and open to robust evaluation.

Understanding the structural drivers governing glass-water interactions in borosilicate based model bioactive glasses.

PubMed

Stone-Weiss, Nicholas; Pierce, Eric M; Youngman, Randall E; Gulbiten, Ozgur; Smith, Nicholas J; Du, Jincheng; Goel, Ashutosh

2018-01-01

The past decade has witnessed a significant upsurge in the development of borate and borosilicate based resorbable bioactive glasses owing to their faster degradation rate in comparison to their silicate counterparts. However, due to our lack of understanding about the fundamental science governing the aqueous corrosion of these glasses, most of the borate/borosilicate based bioactive glasses reported in the literature have been designed by "trial-and-error" approach. With an ever-increasing demand for their application in treating a broad spectrum of non-skeletal health problems, it is becoming increasingly difficult to design advanced glass formulations using the same conventional approach. Therefore, a paradigm shift from the "trial-and-error" approach to "materials-by-design" approach is required to develop new-generations of bioactive glasses with controlled release of functional ions tailored for specific patients and disease states, whereby material functions and properties can be predicted from first principles. Realizing this goal, however, requires a thorough understanding of the complex sequence of reactions that control the dissolution kinetics of bioactive glasses and the structural drivers that govern them. While there is a considerable amount of literature published on chemical dissolution behavior and apatite-forming ability of potentially bioactive glasses, the majority of this literature has been produced on silicate glass chemistries using different experimental and measurement protocols. It follows that inter-comparison of different datasets reveals inconsistencies between experimental groups. There are also some major experimental challenges or choices that need to be carefully navigated to unearth the mechanisms governing the chemical degradation behavior and kinetics of boron-containing bioactive glasses, and to accurately determine the composition-structure-property relationships. In order to address these challenges, a simplified borosilicate based model melt-quenched bioactive glass system has been studied to depict the impact of thermal history on its molecular structure and dissolution behavior in water. It has been shown that the methodology of quenching of the glass melt impacts the dissolution rate of the studied glasses by 1.5×-3× depending on the changes induced in their molecular structure due to variation in thermal history. Further, a recommendation has been made to study dissolution behavior of bioactive glasses using surface area of the sample - to - volume of solution (SA/V) approach instead of the currently followed mass of sample - to - volume of solution approach. The structural and chemical dissolution data obtained from bioactive glasses following the approach presented in this paper can be used to develop the structural descriptors and potential energy functions over a broad range of bioactive glass compositions. Realizing the goal of designing third generation bioactive glasses requires a thorough understanding of the complex sequence of reactions that control their rate of degradation (in physiological fluids) and the structural drivers that control them. In this article, we have highlighted some major experimental challenges and choices that need to be carefully navigated in order to unearth the mechanisms governing the chemical dissolution behavior of borosilicate based bioactive glasses. The proposed experimental approach allows us to gain a new level of conceptual understanding about the composition-structure-property relationships in these glass systems, which can be applied to attain a significant leap in designing borosilicate based bioactive glasses with controlled dissolution rates tailored for specific patient and disease states. Copyright © 2017 Acta Materialia Inc. All rights reserved.

Electronic structural changes of Mn in the oxygen-evolving complex of photosystem II during the catalytic cycle.

PubMed

Glatzel, Pieter; Schroeder, Henning; Pushkar, Yulia; Boron, Thaddeus; Mukherjee, Shreya; Christou, George; Pecoraro, Vincent L; Messinger, Johannes; Yachandra, Vittal K; Bergmann, Uwe; Yano, Junko

2013-05-20

The oxygen-evolving complex (OEC) in photosystem II (PS II) was studied in the S0 through S3 states using 1s2p resonant inelastic X-ray scattering spectroscopy. The spectral changes of the OEC during the S-state transitions are subtle, indicating that the electrons are strongly delocalized throughout the cluster. The result suggests that, in addition to the Mn ions, ligands are also playing an important role in the redox reactions. A series of Mn(IV) coordination complexes were compared, particularly with the PS II S3 state spectrum to understand its oxidation state. We find strong variations of the electronic structure within the series of Mn(IV) model systems. The spectrum of the S3 state best resembles those of the Mn(IV) complexes Mn3(IV)Ca2 and saplnMn2(IV)(OH)2. The current result emphasizes that the assignment of formal oxidation states alone is not sufficient for understanding the detailed electronic structural changes that govern the catalytic reaction in the OEC.

Molecular modeling of the microstructure evolution during carbon fiber processing

NASA Astrophysics Data System (ADS)

Desai, Saaketh; Li, Chunyu; Shen, Tongtong; Strachan, Alejandro

2017-12-01

The rational design of carbon fibers with desired properties requires quantitative relationships between the processing conditions, microstructure, and resulting properties. We developed a molecular model that combines kinetic Monte Carlo and molecular dynamics techniques to predict the microstructure evolution during the processes of carbonization and graphitization of polyacrylonitrile (PAN)-based carbon fibers. The model accurately predicts the cross-sectional microstructure of the fibers with the molecular structure of the stabilized PAN fibers and physics-based chemical reaction rates as the only inputs. The resulting structures exhibit key features observed in electron microcopy studies such as curved graphitic sheets and hairpin structures. In addition, computed X-ray diffraction patterns are in good agreement with experiments. We predict the transverse moduli of the resulting fibers between 1 GPa and 5 GPa, in good agreement with experimental results for high modulus fibers and slightly lower than those of high-strength fibers. The transverse modulus is governed by sliding between graphitic sheets, and the relatively low value for the predicted microstructures can be attributed to their perfect longitudinal texture. Finally, the simulations provide insight into the relationships between chemical kinetics and the final microstructure; we observe that high reaction rates result in porous structures with lower moduli.

Bonding reactivity descriptor from conceptual density functional theory and its applications to elucidate bonding formation

NASA Astrophysics Data System (ADS)

Zhou, Pan-Pan; Liu, Shubin; Ayers, Paul W.; Zhang, Rui-Qin

2017-10-01

Condensed-to-atom Fukui functions which reflect the atomic reactivity like the tendency susceptible to either nucleophilic or electrophilic attack demonstrate the bonding trend of an atom in a molecule. Accordingly, Fukui functions based concepts, that is, bonding reactivity descriptors which reveal the bonding properties of molecules in the reaction were put forward and then applied to pericyclic and cluster reactions to confirm their effectiveness and reliability. In terms of the results from the bonding descriptors, a covalent bond can readily be predicted between two atoms with large Fukui functions (i.e., one governs nucleophilic attack while the other one governs electrophilic attack, or both of them govern radical attacks) for pericyclic reactions. For SinOm clusters' reactions, the clusters with a low O atom ratio readily form a bond between two Si atoms with big values of their Fukui functions in which they respectively govern nucleophilic and electrophilic attacks or both govern radical attacks. Also, our results from bonding descriptors show that Si—Si bonds can be formed via the radical mechanism between two Si atoms, and formations of Si—O and O—O bonds are possible when the O content is high. These results conform with experimental findings and can help experimentalists design appropriate clusters to synthesize Si nanowires with high yields. The approach established in this work could be generalized and applied to study reactivity properties for other systems.

Quantum mechanical reaction probability of triplet ketene at the multireference second-order perturbation level of theory.

PubMed

Ogihara, Yusuke; Yamamoto, Takeshi; Kato, Shigeki

2010-09-23

Triplet ketene exhibits a steplike structure in the experimentally observed dissociation rates, but its mechanism is still unknown despite many theoretical efforts in the past decades. In this paper we revisit this problem by quantum mechanically calculating the reaction probability with multireference-based electronic structure theory. Specifically, we first construct an analytical potential energy surface of triplet state by fitting it to about 6000 ab initio energies computed at the multireference second-order Mller-Plesset perturbation (MRMP2) level. We then evaluate the cumulative reaction probability by using the transition state wave packet method together with an adiabatically constrained Hamiltonian. The result shows that the imaginary barrier frequency on the triplet surface is 328i cm-1, which is close to the CCSD(T) result (321i cm-1) but is likely too large for reproducing the experimentally observed steps. Indeed, our calculated reaction probability exhibits no signature of steps, reflecting too strong tunneling effect along the reaction coordinate. Nevertheless, it is emphasized that the flatness of the potential profile in the transition-state region (which governs the degree of tunneling) depends strongly on the level of electronic structure calculation, thus leaving some possibility that the use of more accurate theories might lead to the observed steps. We also demonstrate that the triplet potential surface differs significantly between the CASSCF and MRMP2 results, particularly in the transition-state region. This fact seems to require more attention when studying the "nonadiabatic" scenario for the steps, in which the crossing seam between S0 and T1 surfaces is assumed to play a central role.

Molecules in motion: influences of diffusion on metabolic structure and function in skeletal muscle

PubMed Central

Kinsey, Stephen T.; Locke, Bruce R.; Dillaman, Richard M.

2011-01-01

Metabolic processes are often represented as a group of metabolites that interact through enzymatic reactions, thus forming a network of linked biochemical pathways. Implicit in this view is that diffusion of metabolites to and from enzymes is very fast compared with reaction rates, and metabolic fluxes are therefore almost exclusively dictated by catalytic properties. However, diffusion may exert greater control over the rates of reactions through: (1) an increase in reaction rates; (2) an increase in diffusion distances; or (3) a decrease in the relevant diffusion coefficients. It is therefore not surprising that skeletal muscle fibers have long been the focus of reaction–diffusion analyses because they have high and variable rates of ATP turnover, long diffusion distances, and hindered metabolite diffusion due to an abundance of intracellular barriers. Examination of the diversity of skeletal muscle fiber designs found in animals provides insights into the role that diffusion plays in governing both rates of metabolic fluxes and cellular organization. Experimental measurements of metabolic fluxes, diffusion distances and diffusion coefficients, coupled with reaction–diffusion mathematical models in a range of muscle types has started to reveal some general principles guiding muscle structure and metabolic function. Foremost among these is that metabolic processes in muscles do, in fact, appear to be largely reaction controlled and are not greatly limited by diffusion. However, the influence of diffusion is apparent in patterns of fiber growth and metabolic organization that appear to result from selective pressure to maintain reaction control of metabolism in muscle. PMID:21177946

In situ probing of the active site geometry of ultrathin nanowires for the oxygen reduction reaction

DOE PAGES

Liu, Haiqing; Wong, Stanislaus S.; An, Wei; ...

2015-09-24

To create truly effective electrocatalysts for the cathodic reaction governing proton exchange membrane fuel cells (PEMFC), namely the oxygen reduction reaction (ORR), necessitates an accurate and detailed structural understanding of these electrocatalysts, especially at the nanoscale, and to precisely correlate that structure with demonstrable performance enhancement. To address this key issue, we have combined and interwoven theoretical calculations with experimental, spectroscopic observations in order to acquire useful structural insights into the active site geometry with implications for designing optimized nanoscale electrocatalysts with rationally predicted properties. Specifically, we have probed ultrathin (~2 nm) core–shell Pt~Pd 9Au nanowires, which have been previouslymore » shown to be excellent candidates for ORR in terms of both activity and long-term stability, from the complementary perspectives of both DFT calculations and X-ray absorption spectroscopy (XAS). The combination and correlation of data from both experimental and theoretical studies has revealed for the first time that the catalytically active structure of our ternary nanowires can actually be ascribed to a PtAu~Pd configuration, comprising a PtAu binary shell and a pure inner Pd core. Moreover, we have plausibly attributed the resulting structure to a specific synthesis step, namely the Cu underpotential deposition (UPD) followed by galvanic replacement with Pt. Thus, the fundamental insights gained into the performance of our ultrathin nanowires from our demonstrated approach will likely guide future directed efforts aimed at broadly improving upon the durability and stability of nanoscale electrocatalysts in general.« less

Thermodynamic interpretation of reactive processes in Ni-Al nanolayers from atomistic simulations

NASA Astrophysics Data System (ADS)

Sandoval, Luis; Campbell, Geoffrey H.; Marian, Jaime

2014-03-01

Metals that can form intermetallic compounds by exothermic reactions constitute a class of reactive materials with multiple applications. Ni-Al laminates of thin alternating layers are being considered as model nanometric metallic multilayers for studying various reaction processes. However, the reaction kinetics at short timescales after mixing are not entirely understood. In this work, we calculate the free energies of Ni-Al alloys as a function of composition and temperature for different solid phases using thermodynamic integration based on state-of-the-art interatomic potentials. We use this information to interpret molecular dynamics (MD) simulations of bilayer systems at 800 K and zero pressure, both in isothermal and isenthalpic conditions. We find that a disordered phase always forms upon mixing as a precursor to a more stable nano crystalline B2 phase. We construe the reactions observed in terms of thermodynamic trajectories governed by the state variables computed. Simulated times of up to 30 ns were achieved, which provides a window to phenomena not previously observed in MD simulations. Our results provide insight into the early experimental reaction timescales and suggest that the path (segregated reactants) → (disordered phase) → (B2 structure) is always realized irrespective of the imposed boundary conditions.

Revealing the reaction mechanisms of Li–O2 batteries using environmental transmission electron microscopy

DOE Office of Scientific and Technical Information (OSTI.GOV)

Luo, Langli; Liu, Bin; Song, Shidong

The capacity, Coulombic efficiency, rate, and cyclability of a Li-O2 battery critically depend on the electrode reaction mechanism and the structure/morphology of the reaction product as well as their spatial and temporal evolution1-8, which are all further complicated by the choice of different electrolyte. For the case of aprotic cell, the discharge product, Li2O2, is formed through solution and surface mechanisms9,10, but little is known on the formation mechanism of the perplexing morphology of the reaction product11-15. For the case of Li-O2 battery using solid electrolyte, neither electrode reaction mechanism nor the nature of the reaction production is known. Herein,more » we reveal the full cycle reaction pathway for Li-O2 batteries and its correlation with the nature of the reaction product. Using an aberration-corrected environmental TEM under oxygen environment, we captured, for the first time, the morphology and phase evolution on the carbon nanotube (CNT) cathode of a working solid-state Li-O2 nano-battery16 and directly correlated these features with electrochemical reaction. We found that the oxygen reduction reaction on CNTs initially produces LiO2, which subsequently evolves to Li2O2 and O2 through disproportionation reaction. Surprisingly it is just the releasing of O2 that inflates the particles to a hollow structure with a Li2O outer surface layer and Li2O2 inner-shell, demonstrating that, in general, accommodation of the released O2 coupled with the Li+ ion diffusion and electron transport paths across both spatial and temporal scales critically governs the morphology of the discharging/charging product in Li-O2 system. We anticipate that the direct observation of Li-O2 reaction mechanisms and their correlation with the morphology of the reaction product set foundation for quantitative understanding/modeling of the electrochemical processes in the Li-O2 system, enabling rational design of both solid-state and aprotic Li-O2 batteries.« less

A network dynamics approach to chemical reaction networks

NASA Astrophysics Data System (ADS)

van der Schaft, A. J.; Rao, S.; Jayawardhana, B.

2016-04-01

A treatment of a chemical reaction network theory is given from the perspective of nonlinear network dynamics, in particular of consensus dynamics. By starting from the complex-balanced assumption, the reaction dynamics governed by mass action kinetics can be rewritten into a form which allows for a very simple derivation of a number of key results in the chemical reaction network theory, and which directly relates to the thermodynamics and port-Hamiltonian formulation of the system. Central in this formulation is the definition of a balanced Laplacian matrix on the graph of chemical complexes together with a resulting fundamental inequality. This immediately leads to the characterisation of the set of equilibria and their stability. Furthermore, the assumption of complex balancedness is revisited from the point of view of Kirchhoff's matrix tree theorem. Both the form of the dynamics and the deduced behaviour are very similar to consensus dynamics, and provide additional perspectives to the latter. Finally, using the classical idea of extending the graph of chemical complexes by a 'zero' complex, a complete steady-state stability analysis of mass action kinetics reaction networks with constant inflows and mass action kinetics outflows is given, and a unified framework is provided for structure-preserving model reduction of this important class of open reaction networks.

Functional links between stability and reactivity of strontium ruthenate single crystals during oxygen evolution

NASA Astrophysics Data System (ADS)

Chang, Seo Hyoung; Danilovic, Nemanja; Chang, Kee-Chul; Subbaraman, Ram; Paulikas, Arvydas P.; Fong, Dillon D.; Highland, Matthew J.; Baldo, Peter M.; Stamenkovic, Vojislav R.; Freeland, John W.; Eastman, Jeffrey A.; Markovic, Nenad M.

2014-06-01

In developing cost-effective complex oxide materials for the oxygen evolution reaction, it is critical to establish the missing links between structure and function at the atomic level. The fundamental and practical implications of the relationship on any oxide surface are prerequisite to the design of new stable and active materials. Here we report an intimate relationship between the stability and reactivity of oxide catalysts in exploring the reaction on strontium ruthenate single-crystal thin films in alkaline environments. We determine that for strontium ruthenate films with the same conductance, the degree of stability, decreasing in the order (001)>(110)>(111), is inversely proportional to the activity. Both stability and reactivity are governed by the potential-induced transformation of stable Ru4+ to unstable Run>4+. This ordered(Ru4+)-to-disordered(Run>4+) transition and the development of active sites for the reaction are determined by a synergy between electronic and morphological effects.

Insulin structure and stability.

PubMed

Brange, J; Langkjoer, L

1993-01-01

Insulin is composed of 51 amino acids in two peptide chains (A and B) linked by two disulfide bonds. The three-dimensional structure of the insulin molecule (insulin monomer), essentially the same in solution and in solid phase, exists in two main conformations. These differ in the extent of helix in the B chain which is governed by the presence of phenol or its derivatives. In acid and neutral solutions, in concentrations relevant for pharmaceutical formulation, the insulin monomer assembles to dimers and at neutral pH, in the presence of zinc ions, further to hexamers. Many crystalline modifications of insulin have been identified but only those with the hexamer as the basic unit are utilized in preparations for therapy. The insulin hexamer forms a relatively stable unit but some flexibility remains within the individual molecules. The intrinsic flexibility at the ends of the B chain plays an important role in governing the physical and chemical stability of insulin. A variety of chemical changes of the primary structure (yielding insulin derivatives), and physical modifications of the secondary to quaternary structures (resulting in "denaturation," aggregation, and precipitation) are known to affect insulin and insulin preparations during storage and use (Fig. 8). The tendency of insulin to undergo structural transformation resulting in aggregation and formation of insoluble insulin fibrils has been one of the most intriguing and widely studied phenomena in relation to insulin stability. Although the exact mechanism of fibril formation is still obscure, it is now clear that the initial step is an exposure of certain hydrophobic residues, normally buried in the three-dimensional structure, to the surface of the insulin monomer. This requires displacement of the COOH-terminal B-chain residues from their normal position which can only be accomplished via monomerization of the insulin. Therefore, most methods stabilizing insulin against fibrillation share the property of being able to counteract associated insulin from being disassembled. Chemical deterioration of insulin during storage of pharmaceutical preparations is mainly due to two categories of chemical reactions, hydrolysis and intermolecular transformation reactions leading to insulin HMWT products. The predominant hydrolysis reaction is deamidation of Asn residues which in acid solution takes place at residue A21, in neutral medium at residue B3. An amazing hydrolytic cleavage of the backbone A chain, presumably autocatalyzed by an adjacent insulin molecule, has been identified in insulin preparations containing rhombohedral crystals in combination with free zinc ions.(ABSTRACT TRUNCATED AT 400 WORDS)

The influence of initial conditions on dispersion and reactions

NASA Astrophysics Data System (ADS)

Wood, B. D.

2016-12-01

In various generalizations of the reaction-dispersion problem, researchers have developed frameworks in which the apparent dispersion coefficient can be negative. Such dispersion coefficients raise several difficult questions. Most importantly, the presence of a negative dispersion coefficient at the macroscale leads to a macroscale representation that illustrates an apparent decrease in entropy with increasing time; this, then, appears to be in violation of basic thermodynamic principles. In addition, the proposition of a negative dispersion coefficient leads to an inherently ill-posed mathematical transport equation. The ill-posedness of the problem arises because there is no unique initial condition that corresponds to a later-time concentration distribution (assuming that if discontinuous initial conditions are allowed). In this presentation, we explain how the phenomena of negative dispersion coefficients actually arise because the governing differential equation for early times should, when derived correctly, incorporate a term that depends upon the initial and boundary conditions. The process of reactions introduces a similar phenomena, where the structure of the initial and boundary condition influences the form of the macroscopic balance equations. When upscaling is done properly, new equations are developed that include source terms that are not present in the classical (late-time) reaction-dispersion equation. These source terms depend upon the structure of the initial condition of the reacting species, and they decrease exponentially in time (thus, they converge to the conventional equations at asymptotic times). With this formulation, the resulting dispersion tensor is always positive-semi-definite, and the reaction terms directly incorporate information about the state of mixedness of the system. This formulation avoids many of the problems that would be engendered by defining negative-definite dispersion tensors, and properly represents the effective rate of reaction at early times.

Mixing and non-equilibrium chemical reaction in a compressible mixing layer. M.S. Thesis Final Report

NASA Technical Reports Server (NTRS)

Steinberger, Craig J.

1991-01-01

The effects of compressibility, chemical reaction exothermicity, and non-equilibrium chemical modeling in a reacting plane mixing layer were investigated by means of two dimensional direct numerical simulations. The chemical reaction was irreversible and second order of the type A + B yields Products + Heat. The general governing fluid equations of a compressible reacting flow field were solved by means of high order finite difference methods. Physical effects were then determined by examining the response of the mixing layer to variation of the relevant non-dimensionalized parameters. The simulations show that increased compressibility generally results in a suppressed mixing, and consequently a reduced chemical reaction conversion rate. Reaction heat release was found to enhance mixing at the initial stages of the layer growth, but had a stabilizing effect at later times. The increased stability manifested itself in the suppression or delay of the formation of large coherent structures within the flow. Calculations were performed for a constant rate chemical kinetics model and an Arrhenius type kinetic prototype. The choice of the model was shown to have an effect on the development of the flow. The Arrhenius model caused a greater temperature increase due to reaction than the constant kinetic model. This had the same effect as increasing the exothermicity of the reaction. Localized flame quenching was also observed when the Zeldovich number was relatively large.

Propagation of gaseous detonation waves in a spatially inhomogeneous reactive medium

NASA Astrophysics Data System (ADS)

Mi, XiaoCheng; Higgins, Andrew J.; Ng, Hoi Dick; Kiyanda, Charles B.; Nikiforakis, Nikolaos

2017-05-01

Detonation propagation in a compressible medium wherein the energy release has been made spatially inhomogeneous is examined via numerical simulation. The inhomogeneity is introduced via step functions in the reaction progress variable, with the local value of energy release correspondingly increased so as to maintain the same average energy density in the medium and thus a constant Chapman-Jouguet (CJ) detonation velocity. A one-step Arrhenius rate governs the rate of energy release in the reactive zones. The resulting dynamics of a detonation propagating in such systems with one-dimensional layers and two-dimensional squares are simulated using a Godunov-type finite-volume scheme. The resulting wave dynamics are analyzed by computing the average wave velocity and one-dimensional averaged wave structure. In the case of sufficiently inhomogeneous media wherein the spacing between reactive zones is greater than the inherent reaction zone length, average wave speeds significantly greater than the corresponding CJ speed of the homogenized medium are obtained. If the shock transit time between reactive zones is less than the reaction time scale, then the classical CJ detonation velocity is recovered. The spatiotemporal averaged structure of the waves in these systems is analyzed via a Favre-averaging technique, with terms associated with the thermal and mechanical fluctuations being explicitly computed. The analysis of the averaged wave structure identifies the super-CJ detonations as weak detonations owing to the existence of mechanical nonequilibrium at the effective sonic point embedded within the wave structure. The correspondence of the super-CJ behavior identified in this study with real detonation phenomena that may be observed in experiments is discussed.

Parameters governing ruthenium sawhorse-based decarboxylation of oleic acid

USDA-ARS?s Scientific Manuscript database

Ruthenium-catalyzed decarboxylation of 9-cisoctadecenoic is a path to produce biobased olefins. Here, a mechanistic study of this reaction was undertaken utilizing a closed reaction system and a pressure reactor. The proposed mechanism of an isomerization followed by a decarboxylation reaction was c...

Effect of interface reaction and diffusion on stress-oxidation coupling at high temperature

NASA Astrophysics Data System (ADS)

Yue, Mengkun; Dong, Xuelin; Fang, Xufei; Feng, Xue

2018-04-01

High-temperature structural materials undergo oxidation during the service, and stress would generate in the oxide film. Understanding the coupling effect between stress and oxidation contributes to the understanding of material degradation and failure during the oxidation process. Here, we propose a model to investigative the coupling effect of stress and oxidation at high temperature by considering the three-stage oxidation process, where both the interface reaction and the diffusion process are present. The governing equations including the oxidation kinetics and stress equilibrium for isothermal oxidation under stress-oxidation coupling effect have been derived. The theory is validated by comparing with the experimental results of SiO2 grown on Si substrate. Results show that the coupling of stress and oxidation influences the growth of the oxide film by affecting all three stages of the oxidation process.

Prediction and characterization of heat-affected zone formation due to neighboring nickel-aluminum multilayer foil reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Adams, David P.; Hirschfeld, Deidre A.; Hooper, Ryan J.

2015-09-01

Reactive multilayer foils have the potential to be used as local high intensity heat sources for a variety of applications. Much of the past research effort concerning these materials have focused on understanding the structure-property relationships of the foils that govern the energy released during a reaction. To enhance the ability of researchers to more rapidly develop technologies based on reactive multilayer foils, a deeper and more predictive understanding of the relationship between the heat released from the foil and microstructural evolution in the neighboring materials is needed. This work describes the development of a numerical model for the purposemore » of evaluating new foil-substrate combinations for screening and optimization. The model is experimentally validated using a commercially available Ni-Al multilayer foils and different alloys.« less

Full numerical simulation of coflowing, axisymmetric jet diffusion flames

NASA Technical Reports Server (NTRS)

Mahalingam, S.; Cantwell, B. J.; Ferziger, J. H.

1990-01-01

The near field of a non-premixed flame in a low speed, coflowing axisymmetric jet is investigated numerically using full simulation. The time-dependent governing equations are solved by a second-order, explicit finite difference scheme and a single-step, finite rate model is used to represent the chemistry. Steady laminar flame results show the correct dependence of flame height on Peclet number and reaction zone thickness on Damkoehler number. Forced simulations reveal a large difference in the instantaneous structure of scalar dissipation fields between nonbuoyant and buoyant cases. In the former, the scalar dissipation marks intense reaction zones, supporting the flamelet concept; however, results suggest that flamelet modeling assumptions need to be reexamined. In the latter, this correspondence breaks down, suggesting that modifications to the flamelet modeling approach are needed in buoyant turbulent diffusion flames.

Structural basis for regioisomerization in the alkali-metal-mediated zincation (AMMZn) of trifluoromethyl benzene by isolation of kinetic and thermodynamic intermediates.

PubMed

Armstrong, David R; Blair, Victoria L; Clegg, William; Dale, Sophie H; Garcia-Alvarez, Joaquin; Honeyman, Gordon W; Hevia, Eva; Mulvey, Robert E; Russo, Luca

2010-07-14

Performed with a desire to advance knowledge of the structures and mechanisms governing alkali-metal-mediated zincation, this study monitors the reaction between the TMP-dialkylzincate reagent [(TMEDA)Na(TMP)((t)Bu)Zn((t)Bu)] 1 and trifluoromethyl benzene C(6)H(5)CF(3) 2. A complicated mixture of products is observed at room temperature. X-ray crystallography has identified two of these products as ortho- and meta-regioisomers of heterotrianionic [(TMEDA)Na(TMP)(C(6)H(4)-CF(3))Zn((t)Bu)], 3-ortho and 3-meta, respectively. Multinuclear NMR data of the bulk crystalline product confirm the presence of these two regioisomers as well as a third isomer, 3-para, in a respective ratio of 20:11:1, and an additional product 4, which also exhibits ortho-zincation of the aryl substrate. Repeating the reaction at 0 degrees C gave exclusively 4, which was crystallographically characterized as [{(TMEDA)(2)Na}(+){Zn(C(6)H(4)-CF(3))((t)Bu)(2)}(-)]. Mimicking the original room-temperature reaction, this kinetic product was subsequently reacted with TMP(H) to afford a complicated mixture of products, including significantly the three regioisomers of 3. Surprisingly, 4 adopts a solvent-separated ion pair arrangement in contrast to the contacted ion variants of 3-ortho and 3-meta. Aided by DFT calculations on model systems, discussion focuses on the different basicities, amido or alkyl, and steps, exhibited in these reactions, and how the structures and bonding within these isolated key metallic intermediates (prior to any electrophilic interception step), specifically the interactions involving the alkali metal, influence the regioselectivity of the Zn-H exchange process.

Towards a global system of vigilance and surveillance in unrelated donors of haematopoietic progenitor cells for transplantation.

PubMed

Shaw, B E; Chapman, J; Fechter, M; Foeken, L; Greinix, H; Hwang, W; Phillips-Johnson, L; Korhonen, M; Lindberg, B; Navarro, W H; Szer, J

2013-11-01

Safety of living donors is critical to the success of blood, tissue and organ transplantation. Structured and robust vigilance and surveillance systems exist as part of some national entities, but historically no global systems are in place to ensure conformity, harmonisation and the recognition of rare adverse events (AEs). The World Health Assembly has recently resolved to require AE/reaction (AE/R) reporting both nationally and globally. The World Marrow Donor Association (WMDA) is an international organisation promoting the safety of unrelated donors and progenitor cell products for use in haematopoietic progenitor cell (HPC) transplantation. To address this issue, we established a system for collecting, collating, analysing, distributing and reacting to serious adverse events and reactions (SAE/R) in unrelated HPC donors. The WMDA successfully instituted this reporting system with 203 SAE/R reported in 2011. The committee generated two rapid reports, reacting to specific SAE/R, resulting in practice changing policies. The system has a robust governance structure, formal feedback to the WMDA membership and transparent information flows to other agencies, specialist physicians and transplant programs and the general public.

Evolution of Structural Empowerment: Moving From Shared to Professional Governance.

PubMed

Clavelle, Joanne T; Porter O'Grady, Tim; Weston, Marla J; Verran, Joyce A

2016-06-01

The aim of this study is to describe the maturation of the concept of shared governance to professional governance as a framework for structural empowerment. An analysis of the literature and concept clarification of structural empowerment and shared governance demonstrate that the concept and attributes of shared governance have evolved toward professional governance. A comprehensive, deductive literature review and concept clarification of structural empowerment, shared governance, and related constructs was completed. The concept and practice of shared governance has matured to a concept of professional governance with the attributes of accountability, professional obligation, collateral relationships, and effective decision-making.

Exploration and exploitation of homologous series of bis(acrylamido)alkanes containing pyridyl and phenyl groups: β-sheet versus two-dimensional layers in solid-state photochemical [2 + 2] reactions.

PubMed

Garai, Mousumi; Biradha, Kumar

2015-09-01

The homologous series of phenyl and pyridyl substituted bis(acrylamido)alkanes have been synthesized with the aim of systematic analysis of their crystal structures and their solid-state [2 + 2] reactivities. The changes in the crystal structures with respect to a small change in the molecular structure, that is by varying alkyl spacers between acrylamides and/or by varying the end groups (phenyl, 2-pyridyl, 3-pyridyl, 4-pyridyl) on the C-terminal of the amide, were analyzed in terms of hydrogen-bonding interference (N-H⋯Npy versus N-H⋯O=C) and network geometries. In this series, a greater tendency towards the formation of N-H⋯O hydrogen bonds (β-sheets and two-dimensional networks) over N-H⋯N hydrogen bonds was observed. Among all the structures seven structures were found to have the required alignments of double bonds for the [2 + 2] reaction such that the formations of single dimer, double dimer and polymer are facilitated. However, only four structures were found to exhibit such a solid-state [2 + 2] reaction to form a single dimer and polymers. The two-dimensional hydrogen-bonding layer via N-H⋯O hydrogen bonds was found to promote solid-state [2 + 2] photo-polymerization in a single-crystal-to-single-crystal manner. Such two-dimensional layers were encountered only when the spacer between acryl amide moieties is butyl. Only four out of the 16 derivatives were found to form hydrates, two each from 2-pyridyl and 4-pyridyl derivatives. The water molecules in these structures govern the hydrogen-bonding networks by the formation of an octameric water cluster and one-dimensional zigzag water chains. The trends in the melting points and densities were also analyzed.

The role of professional communities in governing patient safety.

PubMed

Turner, Simon; Ramsay, Angus; Fulop, Naomi

2013-01-01

Using the example of medication safety, this paper aims to explore the impact of three managerial interventions (adverse incident reporting, ward-level support by pharmacists, and a medication safety subcommittee) on different professional communities situated in the English National Health Service (NHS). Semi-structured interviews were conducted with clinical and managerial staff from two English NHS acute trusts, supplemented with meeting observations and documentary analysis. Attitudes toward managerial intervention differ by professional community (between doctors, nurses and pharmacists) according to their existing norms of safety and perceptions of formal governance processes. The heterogeneity of social norms across different professional communities and medical specialties has implications for the design of organisational learning mechanisms in the field of patient safety. The paper shows that theorisation of professional "resistance" to managerialism privileges the study of doctors' reactions to management with the consequent neglect of the perceptions of other professional communities.

Insights into the glycyl radical enzyme active site of benzylsuccinate synthase: a computational study.

PubMed

Bharadwaj, Vivek S; Dean, Anthony M; Maupin, C Mark

2013-08-21

The fumarate addition reaction, catalyzed by the enzyme benzylsuccinate synthase (BSS), is considered to be one of the most intriguing and energetically challenging reactions in biology. BSS belongs to the glycyl radical enzyme family and catalyzes the fumarate addition reaction, which enables microorganisms to utilize hydrocarbons as an energy source under anaerobic conditions. Unfortunately, the extreme sensitivity of the glycyl radical to oxygen has hampered the structural and kinetic characterization of BSS, thereby limiting our knowledge on this enzyme. To enhance our molecular-level understanding of BSS, a computational approach involving homology modeling, docking studies, and molecular dynamics (MD) simulations has been used to deduce the structure of BSS's catalytic subunit (BSSα) and illuminate the molecular basis for the fumarate addition reaction. We have identified two conserved and distinct binding pockets at the BSSα active site: a hydrophobic pocket for toluene binding and a polar pocket for fumaric acid binding. Subsequent dynamical and energetic evaluations have identified Glu509, Ser827, Leu390, and Phe384 as active site residues critical for substrate binding. The orientation of substrates at the active site observed in MD simulations is consistent with experimental observations of the syn addition of toluene to fumaric acid. It is also found that substrate binding tightens the active site and restricts the conformational flexibility of the thiyl radical, leading to hydrogen transfer distances conducive to the proposed reaction mechanism. The stability of substrates at the active site and the occurrence of feasible radical transfer distances between the thiyl radical, substrates, and the active site glycine indicate a substrate-assisted radical transfer pathway governing fumarate addition.

Public reaction to the UK government strategy on childhood obesity in England: A qualitative and quantitative summary of online reaction to media reports.

PubMed

Gregg, Rebecca; Patel, Ajay; Patel, Sumaiya; O'Connor, Laura

2017-04-01

This work aimed to summarise public real-time reaction to the publication of the UK government childhood obesity strategy by applying a novel research design method. We used a netnographic technique to carry out thematic analysis of user-generated comments to online newspaper articles related to the strategy. We examined likes/dislikes associated with comments as a proxy of agreement of the wider community with identified themes. To examine media influence on the comments we carried out thematic analysis of online media headlines published about the strategy, and compared these themes with themes identified from comments. Three newspaper articles and 1704 associated comments were included. Three parent themes were identified: paternalism/libertarianism, lobbyist influence and, anecdotal solutions. The comments were largely negative (94%). Commenters were split as to individual responsibilities and the role of the government, some felt that lobbyist influence had won out over the nation's health and others offered non-evidence based solutions. The ten most liked and disliked comments reflected themes identified in our main analysis. There was parity between themes that emerged from comments and from headlines. This summary of public reaction to the obesity strategy publication may aid translation of public views and receptiveness into practice and inform subsequent government action and policy. Furthermore, the process applied herein may provide a means of informal public engagement. Copyright © 2017 Elsevier B.V. All rights reserved.

Relationships between Atomic Level Surface Structure and Stability/Activity of Platinum Surface Atoms in Aqueous Environments

DOE PAGES

Lopes, Pietro P.; Strmcnik, Dusan; Tripkovic, Dusan; ...

2016-03-07

The development of alternative energy systems for clean production, storage and conversion of energy is strongly dependent on our ability to understand, at atomic-molecular-levels, functional links between activity and stability of electrochemical interfaces. Whereas structure-activity relationships are rapidly evolving, the corresponding structure-stability relationships are still missing. Primarily, this is because there is no adequate experimental approach capable of monitoring in situ stability of well-defined single crystals. Here, by blending the power of Inductively Coupled Plasma-Mass Spectrometer (ICP-MS) connected to a stationary probe to measure in situ and real time dissolution rates of surface atoms (at above 0.4 pg cm-2s-1 levels)more » and a rotating disk electrode method for monitoring simultaneously the kinetic rates of electrochemical reactions in a single unite, it was possible to establish almost “atom-by-atom” the structure-stability-activity relationships for platinum single crystals in both acidic and alkaline environments. Furthermore, we found that the degree of stability is strongly dependent on the coordination of surface atoms (less coordinated yields less stable), the nature of covalent (adsorption of hydroxyl, oxygen atoms and halides species), and non-covalent interactions (interactions between hydrated Li cations and surface oxide), the thermodynamic driving force for Pt complexation (Pt ion speciation in solution) and the nature of the electrochemical reaction (the oxygen reduction/evolution and CO oxidation reactions). Consequently, these findings are opening new opportunities for elucidating key fundamental descriptors that govern both activity and stability trends, that ultimately, will assist to develop real energy conversion and storage systems.« less

Synthesis of amide-functionalized cellulose esters by olefin cross-metathesis.

PubMed

Meng, Xiangtao; Edgar, Kevin J

2015-11-05

Cellulose esters with amide functionalities were synthesized by cross-metathesis (CM) reaction of terminally olefinic esters with different acrylamides, catalyzed by Hoveyda-Grubbs 2nd generation catalyst. Chelation by amides of the catalyst ruthenium center caused low conversions using conventional solvents. The effects of both solvent and structure of acrylamide on reaction conversion were investigated. While the inherent tendency of acrylamides to chelate Ru is governed by the acrylamide N-substituents, employing acetic acid as a solvent significantly improved the conversion of certain acrylamides, from 50% to up to 99%. Homogeneous hydrogenation using p-toluenesulfonyl hydrazide successfully eliminated the α,β-unsaturation of the CM products to give stable amide-functionalized cellulose esters. The amide-functionalized product showed higher Tg than its starting terminally olefinic counterpart, which may have resulted from strong hydrogen bonding interactions of the amide functional groups. Copyright © 2015 Elsevier Ltd. All rights reserved.

Probability and Cumulative Density Function Methods for the Stochastic Advection-Reaction Equation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barajas-Solano, David A.; Tartakovsky, Alexandre M.

We present a cumulative density function (CDF) method for the probabilistic analysis of $d$-dimensional advection-dominated reactive transport in heterogeneous media. We employ a probabilistic approach in which epistemic uncertainty on the spatial heterogeneity of Darcy-scale transport coefficients is modeled in terms of random fields with given correlation structures. Our proposed CDF method employs a modified Large-Eddy-Diffusivity (LED) approach to close and localize the nonlocal equations governing the one-point PDF and CDF of the concentration field, resulting in a $(d + 1)$ dimensional PDE. Compared to the classsical LED localization, the proposed modified LED localization explicitly accounts for the mean-field advectivemore » dynamics over the phase space of the PDF and CDF. To illustrate the accuracy of the proposed closure, we apply our CDF method to one-dimensional single-species reactive transport with uncertain, heterogeneous advection velocities and reaction rates modeled as random fields.« less

Preprogramming Complex Hydrogel Responses using Enzymatic Reaction Networks.

PubMed

Postma, Sjoerd G J; Vialshin, Ilia N; Gerritsen, Casper Y; Bao, Min; Huck, Wilhelm T S

2017-02-06

The creation of adaptive matter is heavily inspired by biological systems. However, it remains challenging to design complex material responses that are governed by reaction networks, which lie at the heart of cellular complexity. The main reason for this slow progress is the lack of a general strategy to integrate reaction networks with materials. Herein we use a systematic approach to preprogram the response of a hydrogel to a trigger, in this case the enzyme trypsin, which activates a reaction network embedded within the hydrogel. A full characterization of all the kinetic rate constants in the system enabled the construction of a computational model, which predicted different hydrogel responses depending on the input concentration of the trigger. The results of the simulation are in good agreement with experimental findings. Our methodology can be used to design new, adaptive materials of which the properties are governed by reaction networks of arbitrary complexity. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

On the synthesis and structure of resorcinol-formaldehyde polymeric networks – Precursors to 3D-carbon macroassemblies

DOE PAGES

Lewicki, James P.; Fox, Christina A.; Worsley, Marcus A.

2015-05-15

With the new impetus towards the development of hierarchical graphene and CNT macro-assemblies for application in fields such as advanced energy storage, catalysis and electronics; there is much renewed interest in organic carbon-based sol–gel processes as a synthetically convenient and versatile means of forming three dimensional, covalently bonded organic/inorganic networks. Such matrices can act as highly effective precursors, scaffolds or molecular ‘glues’ for the assembly of a wide variety of functional carbon macro-assemblies. However, despite the utility and broad use of organic sol–gel processes – such as the ubiquitous resorcinol-formaldehyde (RF) reaction, there are details of the reaction chemistries ofmore » these important sol–gel processes that remain poorly understood at present. It is therefore both timely and necessary to examine these reactions in more detail using modern analytical techniques in order to gain a more rigorous understanding of the mechanisms by which these organic networks form. The goal of such studies is to obtain improved and rational control over the organic network structure, in order to better direct and tailor the architecture of the final inorganic carbon matrix. In this study we have investigated in detail, the mechanism of the organic sol–gel network forming reaction of resorcinol and formaldehyde from a structural and kinetic standpoint, by using a combination of real-time high field solution state nuclear magnetic resonance (NMR), low field NMR relaxometry and differential scanning calorimetry (DSC). These investigations have allowed us to track the network formation processes in real-time, gain both detailed structural information on the mechanisms of the RF sol–gel process and a quantitative assessment of the kinetics of the global network formation process. Here, it has been shown that the mechanism, by which the RF organic network forms, proceeds via an initial exothermic step correlated to the formation of a free aromatic aldehyde. The network growth reaction then proceeds in a statistical manner following a first order Arrhenius type kinetic relationship – characteristic of a typical thermoset network poly-condensation process. Finally, despite the relative complexity and ill-defined nature of the formaldehyde staring material, the final network structure is to a large extent, governed by the substitution pattern of the resorcinol molecule.« less

Synthesis and controlled release properties of 2,4-dichlorophenoxy acetate-zinc layered hydroxide nanohybrid

NASA Astrophysics Data System (ADS)

Bashi, Abbas M.; Hussein, Mohd Zobir; Zainal, Zulkarnain; Tichit, Didier

2013-07-01

Direct reaction of ZnO with 2,4-dichlorophenoxyacetic acid (24D) solutions of different concentrations allows obtaining new organic-inorganic nanohybrid materials formed by intercalation of 24D into interlayers of zinc layered hydroxide (ZLH). XRD patterns show a progressive evolution of the structure as 24D concentration increases. The nanohybrid obtained at higher 24D concentration (24D-ZLH(0.4)) reveals a well ordered layered structure with two different basal spacings at 25.2 Å and 24 Å. The FTIR spectrum showing the vibrations bands of the functional groups of 24D and of the ZLH confirms the intercalation. SEM images are in agreement with the structural evolution observed by XRD and reveal the ribbon morphology of the nanohybrids. The release studies of 24D showed a rapid release of 94% for the first 100 min governed by the pseudo-second order kinetic model.

Flame Structure and Emissions of Strongly-Pulsed Turbulent Diffusion Flames with Swirl

NASA Astrophysics Data System (ADS)

Liao, Ying-Hao

This work studies the turbulent flame structure, the reaction-zone structure and the exhaust emissions of strongly-pulsed, non-premixed flames with co-flow swirl. The fuel injection is controlled by strongly-pulsing the fuel flow by a fast-response solenoid valve such that the fuel flow is completely shut off between pulses. This control strategy allows the fuel injection to be controlled over a wide range of operating conditions, allowing the flame structure to range from isolated fully-modulated puffs to interacting puffs to steady flames. The swirl level is controlled by varying the ratio of the volumetric flow rate of the tangential air to that of the axial air. For strongly-pulsed flames, both with and without swirl, the flame geometry is strongly impacted by the injection time. Flames appear to exhibit compact, puff-like structures for short injection times, while elongated flames, similar in behaviors to steady flames, occur for long injection times. The flames with swirl are found to be shorter for the same fuel injection conditions. The separation/interaction level between flame puffs in these flames is essentially governed by the jet-off time. The separation between flame puffs decreases as swirl is imposed, consistent with the decrease in flame puff celerity due to swirl. The decreased flame length and flame puff celerity are consistent with an increased rate of air entrainment due to swirl. The highest levels of CO emissions are generally found for compact, isolated flame puffs, consistent with the rapid quenching due to rapid dilution with excess air. The imposition of swirl generally results in a decrease in CO levels, suggesting more rapid and complete fuel/air mixing by imposing swirl in the co-flow stream. The levels of NO emissions for most cases are generally below the steady-flame value. The NO levels become comparable to the steady-flame value for sufficiently short jet-off time. The swirled co-flow air can, in some cases, increase the NO emissions. The elevated NO emissions are due to a longer combustion residence time due to the flow recirculation within the swirl-induced recirculation zone. The reaction zone structure, based on OH planar laser-induced fluorescence (PLIF) is broadly consistent with the observation of luminous flame structure for these types of flames. In many cases, the reaction zone exhibits discontinuities at the instantaneous flame tip in the early period of fuel injection. These discontinuities in the reaction zone likely result from the non-ignition of injected fuel, due to a relatively slower reaction rate in comparison with the mixing rate. The discontinuity in the OH zone is generally seen to diminish with increased swirl level. Statistics generated from the OH PLIF signals show that the reaction zone area generally increases with increased swirl level, consistent with a broader and more convoluted OH-zone structure for flames with swirl. The reaction zone area for swirled flames generally exhibits a higher degree of fluctuation, suggesting a relatively stronger impact of flow turbulence on the flame structure for flames with swirl.

State Structures for the Governance of Higher Education: A Comparative Study.

ERIC Educational Resources Information Center

Bowen, Frank M.; Bracco, Kathy Reeves; Callan, Patrick M.; Finney, Joni E.; Richardson, Richard C., Jr.; Trombley, William

This comparative study synthesizes data from a national study which examined differences among states in their governance structures, and asked if differences in performance were related to governing structures and whether governance structure affected strategies of state policymakers. The seven states examined were grouped into four governance…

Synthesis, quantitative structure-property relationship study of novel fluorescence active 2-pyrazolines and application.

PubMed

Girgis, Adel S; Basta, Altaf H; El-Saied, Houssni; Mohamed, Mohamed A; Bedair, Ahmad H; Salim, Ahmad S

2018-03-01

A variety of fluorescence-active fluorinated pyrazolines 13-33 was synthesized in good yields through cyclocondensation reaction of propenones 1-9 with aryl hydrazines 10-12 . Some of the synthesized compounds provided promising fluorescence properties with quantum yield ( Φ ) higher than that of quinine sulfate (standard reference). Quantitative structure-property relationship studies were undertaken supporting the exhibited fluorescence properties and estimating the parameters governing properties. Five synthesized fluorescence-active pyrazolines ( 13 , 15 , 18 , 19 and 23 ) with variable Φ were selected for treating two types of paper sheets (Fabriano and Bible paper). These investigated fluorescence compounds, especially compounds 19 and 23 , provide improvements in strength properties of paper sheets. Based on the observed performance they can be used as markers in security documents.

Synthesis, quantitative structure-property relationship study of novel fluorescence active 2-pyrazolines and application

NASA Astrophysics Data System (ADS)

Girgis, Adel S.; Basta, Altaf H.; El-Saied, Houssni; Mohamed, Mohamed A.; Bedair, Ahmad H.; Salim, Ahmad S.

2018-03-01

A variety of fluorescence-active fluorinated pyrazolines 13-33 was synthesized in good yields through cyclocondensation reaction of propenones 1-9 with aryl hydrazines 10-12. Some of the synthesized compounds provided promising fluorescence properties with quantum yield (Φ) higher than that of quinine sulfate (standard reference). Quantitative structure-property relationship studies were undertaken supporting the exhibited fluorescence properties and estimating the parameters governing properties. Five synthesized fluorescence-active pyrazolines (13, 15, 18, 19 and 23) with variable Φ were selected for treating two types of paper sheets (Fabriano and Bible paper). These investigated fluorescence compounds, especially compounds 19 and 23, provide improvements in strength properties of paper sheets. Based on the observed performance they can be used as markers in security documents.

2012 Photosynthesis Gordon Research Conference and Seminar, JUL 7-13, 2012

DOE Office of Scientific and Technical Information (OSTI.GOV)

Debus, Richard

2012-07-13

The Gordon Research Conference on PHOTOSYNTHESIS was held at Davidson College, Davidson, North Carolina, July 8-13, 2012. The Conference was well-attended with 150 participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. Of the 150 attendees, 65 voluntarily responded to a general inquiry regarding ethnicity which appears on our registration forms. Of the 65 respondents, 20% were Minorities$-$ 5% Hispanic, 15% Asian and 0% African American. Approximately 28% of the participants at the 2012 meeting were women.more » The Gordon Research Seminar on PHOTOSYNTHESIS held at Davidson College, Davidson, North Carolina, July 7-8, 2012.. The Conference was well-attended with 51 participants (attendees list attached). The attendees represented the spectrum of endeavor in this field coming from academia, industry, and government laboratories, both U.S. and foreign scientists, senior researchers, young investigators, and students. Of the 51 attendees, 22 voluntarily responded to a general inquiry regarding ethnicity which appears on our registration forms. Of the 22 respondents, 14% were Minorities $-$0% Hispanic, 14% Asian and 0% African American. Approximately 35% of the participants at the 2012 meeting were women. Focal points for talks and discussions will include: Artificial photosynthesis and solar energy conversion strategies; Engineering organisms for biofuels and hydrogen production; Electron transport, proton transport, and energy coupling; Photoprotection mechanisms; Photosynthetic reaction center structure and function, including rewiring reaction centers for artificial photosynthesis; Energy capture and light harvesting solutions, including quantum coherence; Structure of the oxygen evolving complex and the mechanism of oxygen production.« less

Introducing Fe 2+ into Nickel-Iron Layered Double Hydroxide: Local Structure Modulated Water Oxidation Activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cai, Zhao; Zhou, Daojin; Wang, Maoyu

Exploring materials with regulated local structures and understanding how the atomic motifs govern the reactivity and durability of catalysts are a critical challenge for designing advanced catalysts. Here we report the tuning of the local atomic structure of nickel–iron layered double hydroxides (NiFe–LDHs) by partially substituting Ni 2+ with Fe 2+ to introduce Fe–O–Fe moieties. These Fe 2+–containing NiFe–LDHs exhibit enhanced oxygen evolution reaction (OER) activity with an ultralow overpotential of 195 mV at the current density of 10 mA/cm 2, which is among the best OER catalytic performance reported to date. In–situ X–ray absorption, Raman, and electrochemical analysis jointlymore » reveal that the Fe–O–Fe motifs could stabilize high–valent metal sites at low overpotentials, thereby enhancing the OER activity. Lastly, these results reveal the importance of tuning the local atomic structure for designing high efficiency electrocatalysts.« less

Introducing Fe2+ into Nickel-Iron Layered Double Hydroxide: Local Structure Modulated Water Oxidation Activity.

PubMed

Cai, Zhao; Zhou, Daojin; Wang, Maoyu; Bak, Seongmin; Wu, Yueshen; Wu, Zishan; Tian, Yang; Xiong, Xuya; Li, Yaping; Liu, Wen; Siahrostami, Samira; Kuang, Yun; Yang, Xiao-Qing; Duan, Haohong; Feng, Zhenxing; Wang, Hailiang; Sun, Xiaoming

2018-06-11

Exploring materials with regulated local structures and understanding how the atomic motifs govern the reactivity and durability of catalysts are a critical challenge for designing advanced catalysts. Here we report the tuning of the local atomic structure of nickel-iron layered double hydroxides (NiFe-LDHs) by partially substituting Ni2+ with Fe2+ to introduce Fe-O-Fe moieties. These Fe2+-containing NiFe-LDHs exhibit enhanced oxygen evolution reaction (OER) activity with an ultralow overpotential of 195 mV at the current density of 10 mA/cm2, which is among the best OER catalytic performance reported to date. In-situ X-ray absorption, Raman, and electrochemical analysis jointly reveal that the Fe-O-Fe motifs could stabilize high-valent metal sites at low overpotentials, thereby enhancing the OER activity. These results reveal the importance of tuning the local atomic structure for designing high efficiency electrocatalysts. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Introducing Fe 2+ into Nickel-Iron Layered Double Hydroxide: Local Structure Modulated Water Oxidation Activity

DOE PAGES

Cai, Zhao; Zhou, Daojin; Wang, Maoyu; ...

2018-06-11

Exploring materials with regulated local structures and understanding how the atomic motifs govern the reactivity and durability of catalysts are a critical challenge for designing advanced catalysts. Here we report the tuning of the local atomic structure of nickel–iron layered double hydroxides (NiFe–LDHs) by partially substituting Ni 2+ with Fe 2+ to introduce Fe–O–Fe moieties. These Fe 2+–containing NiFe–LDHs exhibit enhanced oxygen evolution reaction (OER) activity with an ultralow overpotential of 195 mV at the current density of 10 mA/cm 2, which is among the best OER catalytic performance reported to date. In–situ X–ray absorption, Raman, and electrochemical analysis jointlymore » reveal that the Fe–O–Fe motifs could stabilize high–valent metal sites at low overpotentials, thereby enhancing the OER activity. Lastly, these results reveal the importance of tuning the local atomic structure for designing high efficiency electrocatalysts.« less

Tangled nonlinear driven chain reactions of all optical singularities

NASA Astrophysics Data System (ADS)

Vasil'ev, V. I.; Soskin, M. S.

2012-03-01

Dynamics of polarization optical singularities chain reactions in generic elliptically polarized speckle fields created in photorefractive crystal LiNbO3 was investigated in details Induced speckle field develops in the tens of minutes scale due to photorefractive 'optical damage effect' induced by incident beam of He-Ne laser. It was shown that polarization singularities develop through topological chain reactions of developing speckle fields driven by photorefractive nonlinearities induced by incident laser beam. All optical singularities (C points, optical vortices, optical diabolos,) are defined by instantaneous topological structure of the output wavefront and are tangled by singular optics lows. Therefore, they have develop in tangled way by six topological chain reactions driven by nonlinear processes in used nonlinear medium (photorefractive LiNbO3:Fe in our case): C-points and optical diabolos for right (left) polarized components domains with orthogonally left (right) polarized optical vortices underlying them. All elements of chain reactions consist from loop and chain links when nucleated singularities annihilated directly or with alien singularities in 1:9 ratio. The topological reason of statistics was established by low probability of far enough separation of born singularities pair from existing neighbor singularities during loop trajectories. Topology of developing speckle field was measured and analyzed by dynamic stokes polarimetry with few seconds' resolution. The hierarchy of singularities govern scenario of tangled chain reactions was defined. The useful space-time data about peculiarities of optical damage evolution were obtained from existence and parameters of 'islands of stability' in developing speckle fields.

The supramolecular chemistry of lipid oxidation and antioxidation in bulk oils

PubMed Central

Budilarto, Elizabeth S; Kamal-Eldin, Afaf

2015-01-01

The microenvironment formed by surface active compounds is being recognized as the active site of lipid oxidation. Trace amounts of water occupy the core of micro micelles and several amphiphilic minor components (e.g., phospholipids, monoacylglycerols, free fatty acids, etc.) act as surfactants and affect lipid oxidation in a complex fashion dependent on the structure and stability of the microemulsions in a continuous lipid phase such as bulk oil. The structures of the triacylglycerols and other lipid-soluble molecules affect their organization and play important roles during the course of the oxidation reactions. Antioxidant head groups, variably located near the water-oil colloidal interfaces, trap and scavenge radicals according to their location and concentration. According to this scenario, antioxidants inhibit lipid oxidation not only by scavenging radicals via hydrogen donation but also by physically stabilizing the micelles at the microenvironments of the reaction sites. There is a cut-off effect (optimum value) governing the inhibitory effects of antioxidants depending inter alias on their hydrophilic/lipophilic balance and their concentrations. These complex effects, previously considered as paradoxes in antioxidants research, are now better explained by the supramolecular chemistry of lipid oxidation and antioxidants, which is discussed in this review. PMID:26448722

In Situ, Time-Resolved, and Mechanistic Studies of Metal–Organic Framework Nucleation and Growth

DOE Office of Scientific and Technical Information (OSTI.GOV)

Van Vleet, Mary J.; Weng, Tingting; Li, Xinyi

The vast chemical and structural diversity of metal–organic frameworks (MOFs) opens up the exciting possibility of “crystal engineering” MOFs tailored for particular catalytic or separation applications. Yet the process of reaction discovery, optimization, and scale-up of MOF synthesis remains extremely challenging, presenting significant obstacles to the synthetic realization of many otherwise promising MOF structures. Recently, significant new insights into the fundamental processes governing MOF nucleation and growth, as well as the relationship between reaction parameters and synthetic outcome, have been derived using powerful in situ, time-resolved and/or mechanistic studies of MOF crystallization. This Review provides a summary and associated criticalmore » analysis of the results of these and other related “direct” studies of MOF nucleation and growth, with a particular emphasis on the recent advances in instrument technologies that have enabled such studies and on the major hypotheses, theories, and models that have been used to explain MOF formation. We conclude with a summary of the major insights that have been gained from the work summarized in this Review, outlining our own perspective on potential fruitful new directions for investigation.« less

High-Resolution Tracking Asymmetric Lithium Insertion and Extraction and Local Structure Ordering in SnS2.

PubMed

Gao, Peng; Wang, Liping; Zhang, Yu-Yang; Huang, Yuan; Liao, Lei; Sutter, Peter; Liu, Kaihui; Yu, Dapeng; Wang, En-Ge

2016-09-14

In the rechargeable lithium ion batteries, the rate capability and energy efficiency are largely governed by the lithium ion transport dynamics and phase transition pathways in electrodes. Real-time and atomic-scale tracking of fully reversible lithium insertion and extraction processes in electrodes, which would ultimately lead to mechanistic understanding of how the electrodes function and why they fail, is highly desirable but very challenging. Here, we track lithium insertion and extraction in the van der Waals interactions dominated SnS2 by in situ high-resolution TEM method. We find that the lithium insertion occurs via a fast two-phase reaction to form expanded and defective LiSnS2, while the lithium extraction initially involves heterogeneous nucleation of intermediate superstructure Li0.5SnS2 domains with a 1-4 nm size. Density functional theory calculations indicate that the Li0.5SnS2 is kinetically favored and structurally stable. The asymmetric reaction pathways may supply enlightening insights into the mechanistic understanding of the underlying electrochemistry in the layered electrode materials and also suggest possible alternatives to the accepted explanation of the origins of voltage hysteresis in the intercalation electrode materials.

In Situ, Time-Resolved, and Mechanistic Studies of Metal–Organic Framework Nucleation and Growth

DOE PAGES

Van Vleet, Mary J.; Weng, Tingting; Li, Xinyi; ...

2018-03-07

The vast chemical and structural diversity of metal–organic frameworks (MOFs) opens up the exciting possibility of “crystal engineering” MOFs tailored for particular catalytic or separation applications. Yet the process of reaction discovery, optimization, and scale-up of MOF synthesis remains extremely challenging, presenting significant obstacles to the synthetic realization of many otherwise promising MOF structures. Recently, significant new insights into the fundamental processes governing MOF nucleation and growth, as well as the relationship between reaction parameters and synthetic outcome, have been derived using powerful in situ, time-resolved and/or mechanistic studies of MOF crystallization. This Review provides a summary and associated criticalmore » analysis of the results of these and other related “direct” studies of MOF nucleation and growth, with a particular emphasis on the recent advances in instrument technologies that have enabled such studies and on the major hypotheses, theories, and models that have been used to explain MOF formation. We conclude with a summary of the major insights that have been gained from the work summarized in this Review, outlining our own perspective on potential fruitful new directions for investigation.« less

Electron Transfer Governed Crystal Transformation of Tungsten Trioxide upon Li Ions Intercalation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wang, Zhiguo; He, Yang; Gu, Meng

2016-09-21

Reversible insertion/extraction of ions into a host lattice constitutes the fundamental operating principle of rechargeable battery and electrochromic materials. It is far more commonly observed that insertion of ions into a host lattice can lead to structural evolution of the host lattice, and for the most cases such a lattice evolution is subtle. However, it has never been clear as what kind of factors to control such a lattice structural evolution. Based on tungsten trioxide (WO3) model crystal, we use in situ transmission electron microscopy (TEM) and first principles calculation to explore the nature of Li ions intercalation induced crystalmore » symmetry evolution of WO3. We discovered that Li insertion into the octahedral cavity of WO3 lattice will lead to a low to high symmetry transition, featuring a sequential monoclinic→tetragonal→cubic phase transition. The first principle calculation reveals that the phase transition is essentially governed by the electron transfer from Li to the WO6 octahedrons, which effectively leads to the weakening the W-O bond and modifying system band structure, resulting in an insulator to metal transition. The observation of the electronic effect on crystal symmetry and conductivity is significant, providing deep insights on the intercalation reactions in secondary rechargeable ion batteries and the approach for tailoring the functionalities of material based on insertion of ions in the lattice.« less

On understanding nuclear reaction network flows with branchings on directed graphs

NASA Astrophysics Data System (ADS)

Meyer, Bradley S.

2018-04-01

Nuclear reaction network flow diagrams are useful for understanding which reactions are governing the abundance changes at a particular time during nucleosynthesis. This is especially true when the flows are largely unidirectional, such as during the s-process of nucleosynthesis. In explosive nucleosynthesis, when reaction flows are large, and when forward reactions are nearly balanced by their reverses, reaction flows no longer give a clear picture of the abundance evolution in the network. This paper presents a way of understanding network evolution in terms of sums of branchings on a directed graph, which extends the concept of reaction flows to allow for multiple reaction pathways.

Typology of State-Level Community College Governance Structures

ERIC Educational Resources Information Center

Fletcher, Jeffrey A.; Friedel, Janice Nahra

2017-01-01

Despite having a well-documented history about community colleges across the United States, relatively few discussions have covered state-level governance structures. To understand the typology of state community college governance structures, it must first be recognized that community college governance is characterized as a complex web of…

Structure of Aristotelian electrodynamics

NASA Astrophysics Data System (ADS)

Jacobson, Ted

2015-07-01

Aristotelian electrodynamics (AE) describes the regime of a plasma with a very strong electric field that is not shorted out, with the charge current determined completely by pair production and the balance of the Lorentz 4-force against the curvature radiation reaction. Here it is shown how the principal null directions and associated eigenvalues of the field tensor govern AE, and how force-free electrodynamics arises smoothly from AE when the eigenvalues (and therefore the electric field in some frame) vanish. A criterion for validity of AE and force-free electrodynamics is proposed in terms of a pair of "field curvature scalars" formed from the first derivative of the principal null directions.

Vibrational energy transfer from photoexcited carbon nanotubes to proteins observed by coherent phonon spectroscopy

NASA Astrophysics Data System (ADS)

Nakayama, Tomohito; Yoshizawa, Shunsuke; Hirano, Atsushi; Tanaka, Takeshi; Shiraki, Kentaro; Hase, Muneaki

2017-12-01

Vibrational energy transfer from photoexcited single-wall carbon nanotubes (SWCNTs) to coupled proteins is a key to engineering thermally induced biological reactions, for example, in photothermal therapy. Here, we explored vibrational energy transfer from photoexcited SWCNTs to different adsorbed biological materials by means of a femtosecond pump-probe technique. We show that the vibrational relaxation time of the radial breathing modes in SWCNTs depends significantly on the structure of the coupled materials, that is, proteins or biopolymers, indicating that the vibrational energy transfer is governed by overlapping of the phonon densities of states of the SWCNTs and coupled materials.

State Education Governance Structures: 2017 Update. 50-State Review

ERIC Educational Resources Information Center

Railey, Hunter

2017-01-01

This 50-State Review provides an overview of governance structures in the states, as well as implications for practice, deep dives into four governance models and examples of other governance models. One appendix, State Education Governance Models by State, is included.

Adsorbate-induced lifting of substrate relaxation is a general mechanism governing titania surface chemistry.

PubMed

Silber, David; Kowalski, Piotr M; Traeger, Franziska; Buchholz, Maria; Bebensee, Fabian; Meyer, Bernd; Wöll, Christof

2016-09-30

Under ambient conditions, almost all metals are coated by an oxide. These coatings, the result of a chemical reaction, are not passive. Many of them bind, activate and modify adsorbed molecules, processes that are exploited, for example, in heterogeneous catalysis and photochemistry. Here we report an effect of general importance that governs the bonding, structure formation and dissociation of molecules on oxidic substrates. For a specific example, methanol adsorbed on the rutile TiO 2 (110) single crystal surface, we demonstrate by using a combination of experimental and theoretical techniques that strongly bonding adsorbates can lift surface relaxations beyond their adsorption site, which leads to a significant substrate-mediated interaction between adsorbates. The result is a complex superstructure consisting of pairs of methanol molecules and unoccupied adsorption sites. Infrared spectroscopy reveals that the paired methanol molecules remain intact and do not deprotonate on the defect-free terraces of the rutile TiO 2 (110) surface.

Comparative Physiology of Fatigue.

PubMed

Jones, James H

2016-11-01

This review attempts to provide insights into factors associated with fatigue in human and nonhuman animals by using the two fundamental approaches of comparative physiology: determining common principles that govern structure and function in animals that are relatively invariant between animals and evaluating animals that have been highly adapted by natural selection to demonstrate extreme performance. In this review, I approach the topic of fatigue by considering factors that are associated with its reciprocal or inverse or duration of sustained performance before fatigue sets in to end the performance. The two general factors that I consider that affect endurance time more than any other are body temperature and body mass. The former affects endurance time because of thermodynamic effects on chemical reaction rates and metabolism; the latter acts through the mechanism of allometry or scaling. The examples of extreme animal performance that I discuss are two examples of bird migration, the diving performance of marine mammals, and the unique relationship that governs energy cost of locomotion in hopping kangaroos.

Adsorbate-induced lifting of substrate relaxation is a general mechanism governing titania surface chemistry

NASA Astrophysics Data System (ADS)

Silber, David; Kowalski, Piotr M.; Traeger, Franziska; Buchholz, Maria; Bebensee, Fabian; Meyer, Bernd; Wöll, Christof

2016-09-01

Under ambient conditions, almost all metals are coated by an oxide. These coatings, the result of a chemical reaction, are not passive. Many of them bind, activate and modify adsorbed molecules, processes that are exploited, for example, in heterogeneous catalysis and photochemistry. Here we report an effect of general importance that governs the bonding, structure formation and dissociation of molecules on oxidic substrates. For a specific example, methanol adsorbed on the rutile TiO2(110) single crystal surface, we demonstrate by using a combination of experimental and theoretical techniques that strongly bonding adsorbates can lift surface relaxations beyond their adsorption site, which leads to a significant substrate-mediated interaction between adsorbates. The result is a complex superstructure consisting of pairs of methanol molecules and unoccupied adsorption sites. Infrared spectroscopy reveals that the paired methanol molecules remain intact and do not deprotonate on the defect-free terraces of the rutile TiO2(110) surface.

Rationally engineered flavin-dependent oxidase reveals steric control of dioxygen reduction.

PubMed

Zafred, Domen; Steiner, Barbara; Teufelberger, Andrea R; Hromic, Altijana; Karplus, P Andrew; Schofield, Christopher J; Wallner, Silvia; Macheroux, Peter

2015-08-01

The ability of flavoenzymes to reduce dioxygen varies greatly, and is controlled by the protein environment, which may cause either a rapid reaction (oxidases) or a sluggish reaction (dehydrogenases). Previously, a 'gatekeeper' amino acid residue was identified that controls the reactivity to dioxygen in proteins from the vanillyl alcohol oxidase superfamily of flavoenzymes. We have identified an alternative gatekeeper residue that similarly controls dioxygen reactivity in the grass pollen allergen Phl p 4, a member of this superfamily that has glucose dehydrogenase activity and the highest redox potential measured in a flavoenzyme. A substitution at the alternative gatekeeper site (I153V) transformed the enzyme into an efficient oxidase by increasing dioxygen reactivity by a factor of 60,000. An inverse exchange (V169I) in the structurally related berberine bridge enzyme (BBE) decreased its dioxygen reactivity by a factor of 500. Structural and biochemical characterization of these and additional variants showed that our model enzymes possess a cavity that binds an anion and resembles the 'oxyanion hole' in the proximity of the flavin ring. We showed also that steric control of access to this site is the most important parameter affecting dioxygen reactivity in BBE-like enzymes. Analysis of flavin-dependent oxidases from other superfamilies revealed similar structural features, suggesting that dioxygen reactivity may be governed by a common mechanistic principle. Structural data are available in PDB database under the accession numbers 4PVE, 4PVH, 4PVJ, 4PVK, 4PWB, 4PWC and 4PZF. © 2015 FEBS.

Biconvection flow of Carreau fluid over an upper paraboloid surface: A computational study

NASA Astrophysics Data System (ADS)

Khan, Mair; Hussain, Arif; Malik, M. Y.; Salahuddin, T.

Present article explored the physical characteristics of biconvection effects on the MHD flow of Carreau nanofluid over upper horizontal surface of paraboloid revolution along with chemical reaction. The concept of the Carreau nanofluid was introduced the new parameterization achieve the momentum governing equation. Using similarity transformed, the governing partial differential equations are converted into the ordinary differential equations. The obtained governing equations are solved computationally by using implicit finite difference method known as the Keller box technique. The numerical solutions are obtained for the velocity, temperature, concentration, friction factor, local heat and mass transfer coefficients by varying controlling parameters i.e. Biconvection parameter, fluid parameter, Weissenberg number, Hartmann number, Prandtl number, Brownian motion parameter, thermophoresis parameter, Lewis number and chemical reaction parameter. The obtained results are discussed via graphs and tables.

Chemical Dynamics of nano-Aluminum and Iodine Based Oxidizers

NASA Astrophysics Data System (ADS)

Little, Brian; Ridge, Claron; Overdeep, Kyle; Slizewski, Dylan; Lindsay, Michael

2017-06-01

As observed in previous studies of nanoenergetic powder composites, micro/nano-structural features such as particle morphology and/or reactant spatial distance are expected to strongly influence properties that govern the combustion behavior of energetic materials (EM). In this study, highly reactive composites containing crystalline iodine (V) oxide or iodate salts with nano-sized aluminum (nAl) were blended by two different processing techniques and then collected as a powder for characterization. Physiochemical techniques such as thermal gravimetric analysis, calorimetry, X-ray diffraction, electron microscopy, high speed photography, pressure profile analysis, temperature programmed reactions, and spectroscopy were employed to characterize these EM with emphasis on correlating the chemical reactivity with inherent structural features and variations in stoichiometry. This work is a continuation of efforts to probe the chemical dynamics of nAl-iodine based composites.

State Structures for the Governance of Higher Education: Michigan Case Study Summary.

ERIC Educational Resources Information Center

Bracco, Kathy Reeves

This case study, part of the State Structures for the Governance of Higher Education study, focuses on governance and related issues in Michigan's higher education system. The study's overall purpose was to examine differences among states in their governance structures, and to determine if differences in performance were related to governing…

75 FR 21634 - Government-Owned Inventions; Availability for Licensing

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-26

... such as cutaneous T-cell lymphoma (CTCL) and skin disorders such as lupus, contact dermatitis, and drug... result in contact dermatitis, exanthematous reactions, and photoallergic reactions. A topical formulation... the indicated licensing contact at the Office of Technology Transfer, National Institutes of Health...

Catalytic and reactive polypeptides and methods for their preparation and use

DOEpatents

Schultz, Peter

1994-01-01

Catalytic and reactive polypeptides include a binding site specific for a reactant or reactive intermediate involved in a chemical reaction of interest. The polypeptides further include at least one active functionality proximate the binding site, where the active functionality is capable of catalyzing or chemically participating in the chemical reaction in such a way that the reaction rate is enhanced. Methods for preparing the catalytic peptides include chemical synthesis, site-directed mutagenesis of antibody and enzyme genes, covalent attachment of the functionalities through particular amino acid side chains, and the like. This invention was made with Government support under Grant Contract No. AI-24695, awarded by the Department of health and Human Services, and under Grant Contract No. N 00014-87-K-0256, awarded by the Office of Naval Research. The Government has certain rights in this invention.

Design Principles of DNA Enzyme-Based Walkers: Translocation Kinetics and Photoregulation.

PubMed

Cha, Tae-Gon; Pan, Jing; Chen, Haorong; Robinson, Heather N; Li, Xiang; Mao, Chengde; Choi, Jong Hyun

2015-07-29

Dynamic DNA enzyme-based walkers complete their stepwise movements along the prescribed track through a series of reactions, including hybridization, enzymatic cleavage, and strand displacement; however, their overall translocation kinetics is not well understood. Here, we perform mechanistic studies to elucidate several key parameters that govern the kinetics and processivity of DNA enzyme-based walkers. These parameters include DNA enzyme core type and structure, upper and lower recognition arm lengths, and divalent metal cation species and concentration. A theoretical model is developed within the framework of single-molecule kinetics to describe overall translocation kinetics as well as each reaction step. A better understanding of kinetics and design parameters enables us to demonstrate a walker movement near 5 μm at an average speed of ∼1 nm s(-1). We also show that the translocation kinetics of DNA walkers can be effectively controlled by external light stimuli using photoisomerizable azobenzene moieties. A 2-fold increase in the cleavage reaction is observed when the hairpin stems of enzyme catalytic cores are open under UV irradiation. This study provides general design guidelines to construct highly processive, autonomous DNA walker systems and to regulate their translocation kinetics, which would facilitate the development of functional DNA walkers.

Colloidal Aggregate Structure under Shear by USANS

NASA Astrophysics Data System (ADS)

Chatterjee, Tirtha; van Dyk, Antony K.; Ginzburg, Valeriy V.; Nakatani, Alan I.

2015-03-01

Paints are complex formulations of polymeric binders, inorganic pigments, dispersants, surfactants, colorants, rheology modifiers, and other additives. A commercially successful paint exhibits a desired viscosity profile over a wide shear rate range from 10-5 s-1 for settling to >104 s-1 for rolling, and spray applications. Understanding paint formulation structure is critical as it governs the paint viscosity profile. However, probing paint formulation structure under shear is a challenging task due to the formulation complexity containing structures with different hierarchical length scales and their alterations under the influence of an external flow field. In this work mesoscale structures of paint formulations under shear are investigated using Ultra Small-Angle Neutron Scattering (rheo-USANS). Contrast match conditions were utilized to independently probe the structure of latex binder particle aggregates and the TiO2 pigment particle aggregates. Rheo-USANS data revealed that the aggregates are fractal in nature and their self-similarity dimensions and correlations lengths depend on the chemistry of the binder particles, the type of rheology modifier present and the shear stress imposed upon the formulation. These results can be explained in the framework of diffusion and reaction limited transient aggregates structure evolution under simple shear.

Super-resolution and super-localization microscopy: A novel tool for imaging chemical and biological processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dong, Bin

2015-01-01

Optical microscopy imaging of single molecules and single particles is an essential method for studying fundamental biological and chemical processes at the molecular and nanometer scale. The best spatial resolution (~ λ/2) achievable in traditional optical microscopy is governed by the diffraction of light. However, single molecule-based super-localization and super-resolution microscopy imaging techniques have emerged in the past decade. Individual molecules can be localized with nanometer scale accuracy and precision for studying of biological and chemical processes.This work uncovered the heterogeneous properties of the pore structures. In this dissertation, the coupling of molecular transport and catalytic reaction at the singlemore » molecule and single particle level in multilayer mesoporous nanocatalysts was elucidated. Most previous studies dealt with these two important phenomena separately. A fluorogenic oxidation reaction of non-fluorescent amplex red to highly fluorescent resorufin was tested. The diffusion behavior of single resorufin molecules in aligned nanopores was studied using total internal reflection fluorescence microscopy (TIRFM).« less

Active sites and mechanisms for H2O2 decomposition over Pd catalysts

PubMed Central

Plauck, Anthony; Stangland, Eric E.; Dumesic, James A.; Mavrikakis, Manos

2016-01-01

A combination of periodic, self-consistent density functional theory (DFT-GGA-PW91) calculations, reaction kinetics experiments on a SiO2-supported Pd catalyst, and mean-field microkinetic modeling are used to probe key aspects of H2O2 decomposition on Pd in the absence of cofeeding H2. We conclude that both Pd(111) and OH-partially covered Pd(100) surfaces represent the nature of the active site for H2O2 decomposition on the supported Pd catalyst reasonably well. Furthermore, all reaction flux in the closed catalytic cycle is predicted to flow through an O–O bond scission step in either H2O2 or OOH, followed by rapid H-transfer steps to produce the H2O and O2 products. The barrier for O–O bond scission is sensitive to Pd surface structure and is concluded to be the central parameter governing H2O2 decomposition activity. PMID:27006504

Integrodifferential formulations of the continuous-time random walk for solute transport subject to bimolecular A +B →0 reactions: From micro- to mesoscopic

NASA Astrophysics Data System (ADS)

Hansen, Scott K.; Berkowitz, Brian

2015-03-01

We develop continuous-time random walk (CTRW) equations governing the transport of two species that annihilate when in proximity to one another. In comparison with catalytic or spontaneous transformation reactions that have been previously considered in concert with CTRW, both species have spatially variant concentrations that require consideration. We develop two distinct formulations. The first treats transport and reaction microscopically, potentially capturing behavior at sharp fronts, but at the cost of being strongly nonlinear. The second, mesoscopic, formulation relies on a separation-of-scales technique we develop to separate microscopic-scale reaction and upscaled transport. This simplifies the governing equations and allows treatment of more general reaction dynamics, but requires stronger smoothness assumptions of the solution. The mesoscopic formulation is easily tractable using an existing solution from the literature (we also provide an alternative derivation), and the generalized master equation (GME) for particles undergoing A +B →0 reactions is presented. We show that this GME simplifies, under appropriate circumstances, to both the GME for the unreactive CTRW and to the advection-dispersion-reaction equation. An additional major contribution of this work is on the numerical side: to corroborate our development, we develop an indirect particle-tracking-partial-integro-differential-equation (PIDE) hybrid verification technique which could be applicable widely in reactive anomalous transport. Numerical simulations support the mesoscopic analysis.

Barrierless Reactions with Loose Transition States Govern the Yields and Lifetimes of Organic Nitrates Derived from Isoprene

EPA Science Inventory

The chemical reaction mechanism of NO addition to two β and δ isoprene hydroxy–peroxy radical isomers is examined in detail using density functional theory, coupled cluster methods, and the energy resolved master equation formalism to provide estimates of rate co...

The structure of mass-loading shocks. [interaction of solar wind with cometary coma or local interstellar medium using two-fluid model

NASA Technical Reports Server (NTRS)

Zank, G. P.; Khabibrakhmanov, I. KH.; Story, T.

1993-01-01

A new two-fluid model which describes mass loading in the solar wind (e.g., the interaction of the solar wind with a cometary coma or the local interstellar medium) is presented. The self-consistent back-reaction of the mass-loaded ions is included through their effective scattering in low-frequency MHD turbulence and the invocation of a diffusive approximation. Such an approximation has the advantage of introducing self-consistent dissipation coefficients into the governing equations, thereby facilitating the investigation of the internal structure of shocks in mass-loading environments. To illustrate the utility of the new model, we consider the structure of cometary shocks in the hypersonic one-dimensional limit, finding that the incoming solar wind is slowed by both mass loading and the development of a large cometary ion pressure gradient. The shock is broadened and smoothed by the cometary ions with a thickness of the order of the cometary ion diffusion scale.

Microfluidic Technology: Uncovering the Mechanisms of Nanocrystal Nucleation and Growth.

PubMed

Lignos, Ioannis; Maceiczyk, Richard; deMello, Andrew J

2017-05-16

The controlled and reproducible formation of colloidal semiconductor nanocrystals (or quantum dots) is of central importance in nanoscale science and technology. The tunable size- and shape-dependent properties of such materials make them ideal candidates for the development of efficient and low-cost displays, solar cells, light-emitting devices, and catalysts. The formidable difficulties associated with the macroscale preparation of semiconductor nanocrystals (possessing bespoke optical and chemical properties) result from the fact that underlying reaction mechanisms are complex and that the reactive environment is difficult to control. Automated microfluidic reactors coupled with monitoring systems and optimization algorithms aim to elucidate complex reaction mechanisms that govern both nucleation and growth of nanocrystals. Such platforms are ideally suited for the efficient optimization of reaction parameters, assuring the reproducible synthesis of nanocrystals with user-defined properties. This Account aims to inform the nanomaterials community about how microfluidic technologies can supplement flask experimentation for the ensemble investigation of formation mechanisms and design of semiconductor nanocrystals. We present selected studies outlining the preparation of quantum dots using microfluidic systems with integrated analytics. Such microfluidic reaction systems leverage the ability to extract real-time information regarding optical, structural, and compositional characteristics of quantum dots during nucleation and growth stages. The Account further highlights our recent research activities focused on the development and application of droplet-based microfluidics with integrated optical detection systems for the efficient and rapid screening of reaction conditions and a better understanding of the mechanisms of quantum dot synthesis. We describe the features and operation of fully automated microfluidic reactors and their subsequent application to high-throughput parametric screening of metal chalcogenides (CdSe, PbS, PbSe, CdSeTe), ternary and core/shell heavy metal-free quantum dots (CuInS 2 , CuInS 2 /ZnS), and all-inorganic perovskite nanocrystals (CsPbX 3 , X = Cl, Br, I) syntheses. Critically, concurrent absorption and photoluminescence measurements on millisecond to second time scales allow the extraction of basic parameters governing nanocrystal formation. Moreover, experimental data obtained from such microfluidic platforms can be directly supported by theoretical models of nucleation and growth. To this end, we also describe the use of metamodeling algorithms able to accurately predict optimized conditions of CdSe synthesis using a minimal number of sample parameters. Importantly, we discuss future challenges that must be addressed before microfluidic technologies are in a position to be widely adopted for the on-demand formation of nanocrystals. From a technology perspective, these challenges include the development of novel engineering platforms for the formation of complex architectures, the integration of monitoring systems able to harvest photophysical and structural information, the incorporation of continuous purification systems, and the application of optimization algorithms to multicomponent quantum dot systems.

Study the effect of chemical reaction and variable viscosity on free convection MHD radiating flow over an inclined plate bounded by porous medium

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ali, M., E-mail: ali.mehidi93@gmail.com; Department of Mathematics, Chittagong University of Engineering and Technology, Chittagong-4349; Alim, M. A., E-mail: maalim@math.buet.ac.bd

An analysis is performed to study the free convection heat and mass transfer flow of an electrically conducting incompressible viscous fluid about a semi-infinite inclined porous plate under the action of radiation, chemical reaction in presence of magnetic field with variable viscosity. The dimensionless governing equations are steady, two-dimensional coupled and non-linear ordinary differential equation. Nachtsgeim-Swigert shooting iteration technique along with Runge-Kutta integration scheme is used to solve the non-dimensional governing equations. The effects of magnetic parameter, viscosity parameter and chemical reaction parameter on velocity, temperature and concentration profiles are discussed numerically and shown graphically. Therefore, the results of velocitymore » profile decreases for increasing values of magnetic parameter and viscosity parameter but there is no effect for reaction parameter. The temperature profile decreases in presence of magnetic parameter, viscosity parameter and Prandtl number but increases for radiation parameter. Also, concentration profile decreases for the increasing values of magnetic parameter, viscosity parameter and reaction parameter. All numerical calculations are done with respect to salt water and fixed angle of inclination of the plate.« less

Rule-based modeling and simulations of the inner kinetochore structure.

PubMed

Tschernyschkow, Sergej; Herda, Sabine; Gruenert, Gerd; Döring, Volker; Görlich, Dennis; Hofmeister, Antje; Hoischen, Christian; Dittrich, Peter; Diekmann, Stephan; Ibrahim, Bashar

2013-09-01

Combinatorial complexity is a central problem when modeling biochemical reaction networks, since the association of a few components can give rise to a large variation of protein complexes. Available classical modeling approaches are often insufficient for the analysis of very large and complex networks in detail. Recently, we developed a new rule-based modeling approach that facilitates the analysis of spatial and combinatorially complex problems. Here, we explore for the first time how this approach can be applied to a specific biological system, the human kinetochore, which is a multi-protein complex involving over 100 proteins. Applying our freely available SRSim software to a large data set on kinetochore proteins in human cells, we construct a spatial rule-based simulation model of the human inner kinetochore. The model generates an estimation of the probability distribution of the inner kinetochore 3D architecture and we show how to analyze this distribution using information theory. In our model, the formation of a bridge between CenpA and an H3 containing nucleosome only occurs efficiently for higher protein concentration realized during S-phase but may be not in G1. Above a certain nucleosome distance the protein bridge barely formed pointing towards the importance of chromatin structure for kinetochore complex formation. We define a metric for the distance between structures that allow us to identify structural clusters. Using this modeling technique, we explore different hypothetical chromatin layouts. Applying a rule-based network analysis to the spatial kinetochore complex geometry allowed us to integrate experimental data on kinetochore proteins, suggesting a 3D model of the human inner kinetochore architecture that is governed by a combinatorial algebraic reaction network. This reaction network can serve as bridge between multiple scales of modeling. Our approach can be applied to other systems beyond kinetochores. Copyright © 2013 Elsevier Ltd. All rights reserved.

Prebiotic Synthesis of Autocatalytic Products From Formaldehyde-Derived Sugars as the Carbon and Energy Source

NASA Technical Reports Server (NTRS)

Weber, Arthur L.

2003-01-01

Our research objective is to understand and model the chemical processes on the primitive Earth that generated the first autocatalytic molecules and microstructures involved in the origin of life. Our approach involves: (a) investigation of a model origin-of-life process named the Sugar Model that is based on the reaction of formaldehyde- derived sugars (trioses and tetroses) with ammonia, and (b) elucidation of the constraints imposed on the chemistry of the origin of life by the fixed energies and rates of C,H,O-organic reactions under mild aqueous conditions. Recently, we demonstrated that under mild aqueous conditions the Sugar Model process yields autocatalytic products, and generates organic micropherules (2-20 micron dia.) that exhibit budding, size uniformity, and chain formation. We also discovered that the sugar substrates of the Sugar Model are capable of reducing nitrite to ammonia under mild aqueous conditions. In addition studies done in collaboration with Sandra Pizzarrello (Arizona State University) revealed that chiral amino acids (including meteoritic isovaline) catalyze both the synthesis and specific handedness of chiral sugars. Our systematic survey of the energies and rates of reactions of C,H,O-organic substrates under mild aqueous conditions revealed several general principles (rules) that govern the direction and rate of organic reactions. These reactivity principles constrain the structure of chemical pathways used in the origin of life, and in modern and primitive metabolism.

Phase space barriers and dividing surfaces in the absence of critical points of the potential energy: Application to roaming in ozone

DOE Office of Scientific and Technical Information (OSTI.GOV)

Mauguière, Frédéric A. L., E-mail: frederic.mauguiere@bristol.ac.uk; Collins, Peter, E-mail: peter.collins@bristol.ac.uk; Wiggins, Stephen, E-mail: stephen.wiggins@mac.com

We examine the phase space structures that govern reaction dynamics in the absence of critical points on the potential energy surface. We show that in the vicinity of hyperbolic invariant tori, it is possible to define phase space dividing surfaces that are analogous to the dividing surfaces governing transition from reactants to products near a critical point of the potential energy surface. We investigate the problem of capture of an atom by a diatomic molecule and show that a normally hyperbolic invariant manifold exists at large atom-diatom distances, away from any critical points on the potential. This normally hyperbolic invariantmore » manifold is the anchor for the construction of a dividing surface in phase space, which defines the outer or loose transition state governing capture dynamics. We present an algorithm for sampling an approximate capture dividing surface, and apply our methods to the recombination of the ozone molecule. We treat both 2 and 3 degrees of freedom models with zero total angular momentum. We have located the normally hyperbolic invariant manifold from which the orbiting (outer) transition state is constructed. This forms the basis for our analysis of trajectories for ozone in general, but with particular emphasis on the roaming trajectories.« less

Eight polymorphic microsatellite loci for the Australian plague locust, Chortoicetes terminifera.

PubMed

Chapuis, Marie-Pierre; Popple, Julie-Anne; Simpson, Stephen J; Estoup, Arnaud; Martin, Jean-François; Steinbauer, Martin; McCulloch, Laurence; Sword, Gregory A

2008-11-01

Few population genetics studies have been carried out on major locust species. In particular, an understanding of the population genetic structure of the Australian plague locust, Chortoicetes terminifera, is lacking. We isolated and characterized eight polymorphic microsatellite loci in C. terminifera, and described experimental conditions for polymerase chain reaction multiplexing and genotyping these loci. The number of alleles per locus ranged from 11 to 29 and the expected heterozygosity ranged from 0.797 to 0.977. One locus was found to be X-linked. Results of cross-taxon amplification tests are reported in four species of the Oedipodinae subfamily. Journal compilation © 2008 Blackwell Publishing Ltd. No claim to original US government works.

Time to reorganize federal Earth system science and technology?

NASA Astrophysics Data System (ADS)

Kisslinger, Carl

My usual reaction to plans to reorganize activities in the federal government is that these are the last resort of a bureaucrat who is faced with a tough problem and has no idea how to solve it. However, this may be the time to consider seriously a reorganization that would assemble key elements of Earth-oriented science and technology into a single federal agency. This is not a new idea, as proposals to achieve this goal have been formulated in the past and wiring diagrams for a new agency have been developed. These proposals have faded away in the face of resistance to substantial structural change that characterizes the federal bureaucracy.

GRIZZLY Model of Multi-Reactive Species Diffusion, Moisture/Heat Transfer and Alkali-Silica Reaction for Simulating Concrete Aging and Degradation

DOE Office of Scientific and Technical Information (OSTI.GOV)

Huang, Hai; Spencer, Benjamin W.; Cai, Guowei

Concrete is widely used in the construction of nuclear facilities because of its structural strength and its ability to shield radiation. The use of concrete in nuclear power plants for containment and shielding of radiation and radioactive materials has made its performance crucial for the safe operation of the facility. As such, when life extension is considered for nuclear power plants, it is critical to have accurate and reliable predictive tools to address concerns related to various aging processes of concrete structures and the capacity of structures subjected to age-related degradation. The goal of this report is to document themore » progress of the development and implementation of a fully coupled thermo-hydro-mechanical-chemical model in GRIZZLY code with the ultimate goal to reliably simulate and predict long-term performance and response of aged NPP concrete structures subjected to a number of aging mechanisms including external chemical attacks and volume-changing chemical reactions within concrete structures induced by alkali-silica reactions and long-term exposure to irradiation. Based on a number of survey reports of concrete aging mechanisms relevant to nuclear power plants and recommendations from researchers in concrete community, we’ve implemented three modules during FY15 in GRIZZLY code, (1) multi-species reactive diffusion model within cement materials; (2) coupled moisture and heat transfer model in concrete; and (3) anisotropic, stress-dependent, alkali-silica reaction induced swelling model. The multi-species reactive diffusion model was implemented with the objective to model aging of concrete structures subjected to aggressive external chemical attacks (e.g., chloride attack, sulfate attack, etc.). It considers multiple processes relevant to external chemical attacks such as diffusion of ions in aqueous phase within pore spaces, equilibrium chemical speciation reactions and kinetic mineral dissolution/precipitation. The moisture/heat transfer module was implemented to simulate long-term spatial and temporal evolutions of the moisture and temperature fields within concrete structures at both room and elevated temperatures. The ASR swelling model implemented in GRIZZLY code can simulate anisotropic expansions of ASR gel under either uniaxial, biaxial and triaxial stress states, and can be run simultaneously with the moisture/heat transfer model and coupled with various elastic/inelastic solid mechanics models that were implemented in GRIZZLY code previously. This report provides detailed descriptions of the governing equations, constitutive equations and numerical algorithms of the three modules implemented in GRIZZLY during FY15, simulation results of example problems and model validation results by comparing simulations with available experimental data reported in the literature. The close match between the experiments and simulations clearly demonstrate the potential of GRIZZLY code for reliable evaluation and prediction of long-term performance and response of aged concrete structures in nuclear power plants.« less

Semiconductor structural damage attendant to contact formation in III-V solar cells

NASA Technical Reports Server (NTRS)

Fatemi, Navid S.; Weizer, Victor G.

1991-01-01

In order to keep the resistive losses in solar cells to a minimum, it is often necessary for the ohmic contacts to be heat treated to lower the metal-semiconductor contact resistivity to acceptable values. Sintering of the contacts, however can result in extensive mechanical damage of the semiconductor surface under the metallization. An investigation of the detailed mechanisms involved in the process of contact formation during heat treatment may control the structural damage incurred by the semiconductor surface to acceptable levels, while achieving the desired values of contact resistivity for the ohmic contacts. The reaction kinetics of sintered gold contacts to InP were determined. It was found that the Au-InP interaction involves three consecutive stages marked by distinct color changes observed on the surface of the Au, and that each stage is governed by a different mechanism. A detailed description of these mechanisms and options to control them are presented.

Acenaphthenequinone thiosemicarbazone and its transition metal complexes: synthesis, structure, and biological activity.

PubMed

Rodriguez-Argüelles, M C; Belicchi Ferrari, M; Gasparri Fava, G; Pelizzi, C; Pelosi, G; Albertini, R; Bonati, A; Dall'Aglio, P P; Lunghi, P; Pinelli, S

1997-04-01

The reaction of iron, nickel, copper, and zinc chlorides or acetates with acenaphthenequinone thiosemicarbazone, Haqtsc leads to the formation of novel complexes that have been characterized by spectroscopic studies (NMR, IR) and biological properties. The crystal structures of the free ligand Haqtsc 1 and of the compound [Ni(aqtsc)2].DMF 2, have also been determined by X-ray methods from diffractometer data. In 1, the conformation of the two nonequivalent molecules is governed by intramolecular hydrogen bonds, while an intermolecular hydrogen bond is responsible for dimer-like groups formation. In 2, the coordination geometry about nickel is distorted octahedral, and the two ligand molecules are terdentate monodeprotonated. Biological studies have shown that, for the first time at least up the used doses, a free ligand is active both in the inhibition of cell proliferation and in the induced differentiation on Friend erythroleukemia cells (FLC).

76 FR 25697 - Government-Owned Inventions; Availability for Licensing

Federal Register 2010, 2011, 2012, 2013, 2014

2011-05-05

...; Availability for Licensing AGENCY: National Institutes of Health, Public Health Service, HHS. ACTION: Notice... commercially available one, which means it now matches the PCR product generated in the qPCR reaction in the... and directly matches the PCR product generated in the qPCR reaction. The standard plasmid is easy to...

The Future of Public Forests: An Institutional Blending Approach to Forest Governance in England

ERIC Educational Resources Information Center

Hodge, Ian D.; Adams, William M.

2013-01-01

Early in 2011, the Government initiated a consultation on the potential sale of the Public Forest Estate in England. This proposal leads to vociferous negative public reaction and the consultation was withdrawn and an Independent Panel established. This paper reviews the arguments as to the options and appropriate institutional arrangements for…

Interfaces in Heterogeneous Catalysts: Advancing Mechanistic Understanding through Atomic-Scale Measurements.

PubMed

Gao, Wenpei; Hood, Zachary D; Chi, Miaofang

2017-04-18

Developing novel catalysts with high efficiency and selectivity is critical for enabling future clean energy conversion technologies. Interfaces in catalyst systems have long been considered the most critical factor in controlling catalytic reaction mechanisms. Interfaces include not only the catalyst surface but also interfaces within catalyst particles and those formed by constructing heterogeneous catalysts. The atomic and electronic structures of catalytic surfaces govern the kinetics of binding and release of reactant molecules from surface atoms. Interfaces within catalysts are introduced to enhance the intrinsic activity and stability of the catalyst by tuning the surface atomic and chemical structures. Examples include interfaces between the core and shell, twin or domain boundaries, or phase boundaries within single catalyst particles. In supported catalyst nanoparticles (NPs), the interface between the metallic NP and support serves as a critical tuning factor for enhancing catalytic activity. Surface electronic structure can be indirectly tuned and catalytically active sites can be increased through the use of supporting oxides. Tuning interfaces in catalyst systems has been identified as an important strategy in the design of novel catalysts. However, the governing principle of how interfaces contribute to catalyst behavior, especially in terms of interactions with intermediates and their stability during electrochemical operation, are largely unknown. This is mainly due to the evolving nature of such interfaces. Small changes in the structural and chemical configuration of these interfaces may result in altering the catalytic performance. These interfacial arrangements evolve continuously during synthesis, processing, use, and even static operation. A technique that can probe the local atomic and electronic interfacial structures with high precision while monitoring the dynamic interfacial behavior in situ is essential for elucidating the role of interfaces and providing deeper insight for fine-tuning and optimizing catalyst properties. Scanning transmission electron microscopy (STEM) has long been a primary characterization technique used for studying nanomaterials because of its exceptional imaging resolution and simultaneous chemical analysis. Over the past decade, advances in STEM, that is, the commercialization of both aberration correctors and monochromators, have significantly improved the spatial and energy resolution. Imaging atomic structures with subangstrom resolution and identifying chemical species with single-atom sensitivity are now routine for STEM. These advancements have greatly benefitted catalytic research. For example, the roles of lattice strain and surface elemental distribution and their effect on catalytic stability and reactivity have been well documented in bimetallic catalysts. In addition, three-dimensional atomic structures revealed by STEM tomography have been integrated in theoretical modeling for predictive catalyst NP design. Recent developments in stable electronic and mechanical devices have opened opportunities to monitor the evolution of catalysts in operando under synthesis and reaction conditions; high-speed direct electron detectors have achieved sub-millisecond time resolutions and allow for rapid structural and chemical changes to be captured. Investigations of catalysts using these latest microscopy techniques have provided new insights into atomic-level catalytic mechanisms. Further integration of new microscopy methods is expected to provide multidimensional descriptions of interfaces under relevant synthesis and reaction conditions. In this Account, we discuss recent insights on understanding catalyst activity, selectivity, and stability using advanced STEM techniques, with an emphasis on how critical interfaces dictate the performance of precious metal-based heterogeneous catalysts. The role of extended interfacial structures, including those between core and shell, between separate phases and twinned grains, between the catalyst surface and gas, and between metal and support are discussed. We also provide an outlook on how emerging electron microscopy techniques, such as vibrational spectroscopy and electron ptychography, will impact future catalysis research.

76 FR 50719 - Models for a Governance Structure for the National Strategy for Trusted Identities in Cyberspace...

Federal Register 2010, 2011, 2012, 2013, 2014

2011-08-16

... DEPARTMENT OF COMMERCE National Institute of Standards and Technology [Docket No. 110524296-1455-02] Models for a Governance Structure for the National Strategy for Trusted Identities in Cyberspace... comments regarding the governance structure for the National Strategy for Trusted Identities in Cyberspace...

Change in University Governance Structures in Continental Europe

ERIC Educational Resources Information Center

Gornitzka, Åse; Maassen, Peter; de Boer, Harry

2017-01-01

This article discusses changes with respect to university governance structures in six comprehensive universities in Europe. We present an analytical framework on the basis of which we conduct a comparative analysis of the university governance structures along four different dimensions: (a) the internal democratic nature of the governance…

Soft dipole resonance and halo structure of 11Li

NASA Astrophysics Data System (ADS)

Kanungo, Rituparna

2016-03-01

The discovery of the nuclear halo in rare isotopes has ushered a new era in nuclear science breaking the boundaries of conventional concepts. The halo properties elucidate new features that till date remain a challenge to decipher from fundamental principles. Our knowledge on the halo is still gradually unfolding and reaching new levels of precision as efforts continue towards new experimental developments. In recent times, low-energy reactions in inverse kinematics have become possible providing a wealth of new structure information. In this presentation we will introduce a new reaction spectroscopy facility, IRIS, with a novel thin windowless solid H2/D2 target for studying transfer and inelastic scattering reactions of rare isotopes with very low yields. It was postulated that the loosely bound halo of two neutrons may lead to a core-halo oscillation resulting in dipole resonance(s) at very low excitation energy, called soft dipole resonance. Despite decades of search for this new phenomenon using various techniques, such as, no firm conclusion was reached. The presentation will discuss new results from IRIS that shows evidence of a soft dipole resonance state and further unveils its isoscalar character. New results of neutron transfer from 11Li will be presented showing resonance state(s) in the neutron unbound 10Li subsystem hence facilitating a description of the wavefunction of 11Li. NSERC, Canada Foundation for Innovation, Nova Scotia Research and Innovation Trust, grant-in-aid program of the Japanese government under Contract No. 23224008, US DOE Contract No. DE-AC52-07NA27344.

Link between alginate reaction front propagation and general reaction diffusion theory.

PubMed

Braschler, Thomas; Valero, Ana; Colella, Ludovica; Pataky, Kristopher; Brugger, Jürgen; Renaud, Philippe

2011-03-15

We provide a common theoretical framework reuniting specific models for the Ca(2+)-alginate system and general reaction diffusion theory along with experimental validation on a microfluidic chip. As a starting point, we use a set of nonlinear, partial differential equations that are traditionally solved numerically: the Mikkelsen-Elgsaeter model. Applying the traveling-wave hypothesis as a major simplification, we obtain an analytical solution. The solution indicates that the fundamental properties of the alginate reaction front are governed by a single dimensionless parameter λ. For small λ values, a large depletion zone accompanies the reaction front. For large λ values, the alginate reacts before having the time to diffuse significantly. We show that the λ parameter is of general importance beyond the alginate model system, as it can be used to classify known solutions for second-order reaction diffusion schemes, along with the novel solution presented here. For experimental validation, we develop a microchip model system, in which the alginate gel formation can be carried out in a highly controlled, essentially 1D environment. The use of a filter barrier enables us to rapidly renew the CaCl(2) solution, while maintaining flow speeds lower than 1 μm/s for the alginate compartment. This allows one to impose an exactly known bulk CaCl(2) concentration and diffusion resistance. This experimental model system, taken together with the theoretical development, enables the determination of the entire set of physicochemical parameters governing the alginate reaction front in a single experiment.

Kinetic consequences of introducing a proximal selenocysteine ligand into cytochrome P450cam.

PubMed

Vandemeulebroucke, An; Aldag, Caroline; Stiebritz, Martin T; Reiher, Markus; Hilvert, Donald

2015-11-10

The structural, electronic, and catalytic properties of cytochrome P450cam are subtly altered when the cysteine that coordinates to the heme iron is replaced with a selenocysteine. To map the effects of the sulfur-to-selenium substitution on the individual steps of the catalytic cycle, we conducted a comparative kinetic analysis of the selenoenzyme and its cysteine counterpart. Our results show that the more electron-donating selenolate ligand has only negligible effects on substrate, product, and oxygen binding, electron transfer, catalytic turnover, and coupling efficiency. Off-pathway reduction of oxygen to give superoxide is the only step significantly affected by the mutation. Incorporation of selenium accelerates this uncoupling reaction approximately 50-fold compared to sulfur, but because the second electron transfer step is much faster, the impact on overall catalytic turnover is minimal. Density functional theory calculations with pure and hybrid functionals suggest that superoxide formation is governed by a delicate interplay of spin distribution, spin state, and structural effects. In light of the remarkably similar electronic structures and energies calculated for the sulfur- and selenium-containing enzymes, the ability of the heavier atom to enhance the rate of spin crossover may account for the experimental observations. Because the selenoenzyme closely mimics wild-type P450cam, even at the level of individual steps in the reaction cycle, selenium represents a unique mechanistic probe for analyzing the role of the proximal ligand and spin crossovers in P450 chemistry.

The Hidden Rule: A Critical Discussion of Harvard University's Governing Structure. [A Harvard Watch Report].

ERIC Educational Resources Information Center

Weissman, Robert

The governing structure of Harvard University is reviewed, and the findings include the following: (1) Harvard's present administrative and governance structure utilize corporate techniques of management that allow the president to diffuse administrative tasks without diffusing power--the difficulty of locating responsibility in the decentralized…

Review of adverse reactions to injections of Chinese materia medica.

PubMed

Bian, Zhaoxiang; Shang, Hongcai; Cheng, Chungwah; Wu, Taixiang; Li, Youping; Zhang, Boli

2010-05-01

Using Chinese Materia Medica (CM) as injections is an innovation that is proving effective in extensive clinical use in Mainland China. However, recent reports have focused on adverse reactions, ignoring the considerable successes of these preparations. In order to achieve balance in the media and in the minds of the public, we suggest the first step is to clarify the concepts of and differences between adverse drug reactions (ADR) and adverse events (AE) for all concerned-the public, medical practitioners, government officials, and lawmakers. Second, the State Food and Drug Administration should raise the requirements for Chinese Materia Medica Injection (CMI) registration and license approval and emphasize the importance of evidence-based CMI development and evidence-based CMI license approval. Thirdly, drug companies and institutions should reinforce basic research about the quality control of herbs and CMI-drug interactions. Fourth, the Government should clarify the legal responsibilities for CMI approval agencies, CMI developers, medical doctors, and patients. Fifth, the medical association and Government should enhance training for health care professionals concerning the usage of CMIs. And finally sixth, State Food and Drug Administration should monitor the content and quality of the directions for use of CMI. © 2010 Blackwell Publishing Asia Pty Ltd and Chinese Cochrane Center, West China Hospital of Sichuan University.

Parent Participation in School Governance: A Legal Analysis of Experiences in South Africa and Kentucky

ERIC Educational Resources Information Center

Bathon, Justin; Beckmann, Johan; Bjork, Lars G.

2011-01-01

This comparative study on the educational governance systems of South Africa and the Commonwealth of Kentucky examines legal evidence from judicial decisions and administrative law to understand similarities in how school-based governance structures have been developed. We found that although school-level governance structures may provide greater…

Institutional analysis of health system governance.

PubMed

Abimbola, Seye; Negin, Joel; Martiniuk, Alexandra L; Jan, Stephen

2017-11-01

It is important that researchers who study health system governance have a set of collective understandings of the meanings of governance, which can then inform the methods used in research. We present an institutional framing and definition of health system governance; that is, governance refers to making, changing, monitoring and enforcing the rules that govern the demand and supply of health services. This pervasive, relational view of governance is to be preferred to approaches that focus primarily on structures of governments and health care organizations, because health system governance involves communities and service users, and because governments in many low- and middle-income countries tend to under-govern. Therefore, the study of health system governance requires institutional analysis; an approach that focuses not only on structures, but also on the rules (both formal and informal) governing demand and supply relations. Using this 'structure-relations' lens, and based on our field experience, we discuss how this focus could be applied to the three approaches to framing and studying health system governance that we identified in the literature. In order of decreasing focus on structures ('hardware') and increasing focus on relations ('software'), they are: (1) the government-centred approach, which focuses on the role of governments, above or to the exclusion of non-government health system actors; (2) the building-block approach, which focuses on the internal workings of health care organizations, and treats governance as one of the several building blocks of organizations; and (3) the institutional approach, which focuses on how the rules governing social and economic interactions are made, changed, monitored and enforced. Notably, either or both qualitative and quantitative methods may be used by researchers in efforts to incorporate the analysis of how rules determine relations among health system actors into these three approaches to health system governance. © The Author 2017. Published by Oxford University Press in association with The London School of Hygiene and Tropical Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Methyl oleate deoxygenation for production of diesel fuel aliphatic hydrocarbons over Pd/SBA-15 catalysts

PubMed Central

2013-01-01

Background Catalytic deoxygenation is a prominent process for production of renewable fuels from vegetable oil. In this work, deoxygenation of technical grade methyl oleate to diesel fuel aliphatic hydrocarbons (C15 – C18) is evaluated with several parameters including temperature, hydrogen pressure and reaction time in a stirred batch reactor over Pd/SBA-15 catalysts. Results Two different SBA-15 morphologies i.e. spherelike and necklacelike structures have been synthesize as supports for Pd active metal. It is found that Pd dispersion on necklacelike SBA-15 is higher than that of spherelike SBA-15. Notably, higher Pd dispersion on necklacelike SBA-15 provides significant deoxygenation efficiency as compared to Pd/SBA-15-spherelike. Results show that H2 pressures greatly determine the total ester conversion and selectivity to C15 – C18 aliphatic hydrocarbons. Total ester conversions with 55< selectivity to n-heptadecane are achieved using Pd/SBA-15-necklacelike at 270°C and 60 bar H2 pressure within 6 h reaction time. Gas phase study reveals that formation of C17 is generated via indirect decarbonylation when the reaction time is prolonged. Conclusions Pd/SBA-15-necklacelike catalyst exhibits good catalytic performance with high selectivity to diesellike aliphatic hydrocarbons (C15 – C18). The physicochemical properties of the Pd supported on different SBA-15 morphologies influence the deoxygenation activity of the catalysts. Furthermore, the reaction pathways are governed by the H2 pressure as well as reaction duration. PMID:24011181

Selective C-O Hydrogenolysis and Decarboxylation of Biomass-Derived Heterocyclic Compounds over Heterogeneous Catalysts

NASA Astrophysics Data System (ADS)

Chia, Mei

The catalytic deoxygenation of biomass-derived compounds through selective C-O hydrogenolysis, catalytic transfer hydrogenation and lactonization, and decarboxylation to value-added chemicals over heterogeneous catalysts was examined under liquid phase reaction conditions. The reactions studied involve the conversion or production of heterocyclic compounds, specifically, cyclic ethers, lactones, and 2-pyrones. A bimetallic RhRe/C catalyst was found to be selective for the hydrogenolysis of secondary C-O bonds for a broad range cyclic ethers and polyols. Results from experimentally-observed reactivity trends, NH3 temperature-programmed desorption, fructose dehydration reaction studies, and first-principles density functional theory (DFT) calculations are consistent with the hypothesis of a bifunctional catalyst which facilitates acid-catalyzed ring-opening and dehydration coupled with metal-catalyzed hydrogenation. C-O hydrogenolysis and fructose dehydration activities were observed to decrease with an increase in reduction temperature and a decrease in the number of surface metallic Re atoms measured by in situ X-ray absorption spectroscopy. No C-O hydrogenolysis activity was detected over RhRe/C under water-free conditions. The activation of water molecules by Re atoms on the surface of metallic Rh is suggested to result in the formation of Bronsted acidity over RhRe/C. The catalytic transfer hydrogenation and lactonization of levulinic acid and its esters to gamma-valerolactone was accomplished through the Meerwein-Ponndorf-Verley reaction over metal oxide catalysts using secondary alcohols as the hydrogen donor. ZrO2 was a highly active material for CTH under batch and continuous flow reaction conditions; the initial activity of the catalyst was repeatedly regenerable by calcination in air, with no observable loss in catalytic activity. Lastly, the 2-pyrone, triacetic acid lactone, is shown to be a promising biorenewable platform chemical from which a wide range of chemical intermediates and end products can be obtained using heterogeneous catalysts or by thermal decomposition. Mechanistic insights from experimentally-observed reactivity trends and results from DFT calculations indicate that 2-pyrones undergo reactions unique to their structure such as keto-enol tautomerization, retro Diels-Alder, and nucleophilic attack by water. Ring-opening and decarboxylation reactions were found to be governed by key structural features such as the degree of saturation in the ring (e.g., C4=C5 bond), nature of the solvent, and presence of an acid catalyst.

Atomistic Conversion Reaction Mechanism of WO 3 in Secondary Ion Batteries of Li, Na, and Ca

DOE Office of Scientific and Technical Information (OSTI.GOV)

He, Yang; Gu, Meng; Xiao, Haiyan

2016-04-13

Reversible insertion and extraction of ionic species into a host lattice governs the basic operating principle for both rechargeable battery (such as lithium batteries) and electrochromic devices (such as ANA Boeing 787-8 Dreamliner electrochromic window). Intercalation and/or conversion are two fundamental chemical processes for some materials in response to the ion insertion. The interplay between these two chemical processes has never been established. It is speculated that the conversion reaction is initiated by ion intercalation. However, experimental evidence of intercalation and subsequent conversion remains unexplored. Here, using in situ HRTEM and spectroscopy, we captured the atomistic conversion reaction processes duringmore » lithium, sodium and calcium ion insertion into tungsten trioxide (WO3) single crystal model electrodes. An intercalation step right prior to conversion is explicitly revealed at atomic scale for the first time for these three ion species. Combining nanoscale diffraction and ab initio molecular dynamics simulations, it is found that, beyond intercalation, the inserted ion-oxygen bonding formation destabilized the transition-metal framework which gradually shrunk, distorted and finally collapsed to a pseudo-amorphous structure. This study provides a full atomistic picture on the transition from intercalation to conversion, which is of essential for material applications in both secondary ion batteries and electrochromic devices.« less

Effects of gravity on sheared and nonsheared turbulent nonpremixed flames

NASA Technical Reports Server (NTRS)

Elghobashi, Said; Lee, Yong-Yao; Zhong, Rongbin

1995-01-01

The present numerical study is concerned with the fundamental physics of the multiway interaction between turbulence, chemical reaction, and buoyancy in a nonpremixed flame. The method of direct numerical simulation (DNS) is used to solve the instantaneous, three-dimensional governing equations. Because of the present supercomputer limitations, we consider two simple flow geometries, namely an initially uniform flow without shear (equivalent to grid-generated turbulence) and an initially uniform shear flow. In each flow, the fuel and oxidant initially exist as two separate streams. As the reactants mix, chemical reaction takes place and exothermic energy is released causing variations in density. In the presence of a gravity field, the spatial and temporal distributions of the induced buoyancy forces depend on the local density gradients and the direction of the gravitational acceleration. The effects of buoyancy include the generation of local shear, baroclinic production or destruction of vorticity, and countergradient heat and mass transport. Increased vorticity and small-scale turbulence promote further mixing and reaction. However, if the strain-rates become too high, local flame extinction can occur. Our objective is to gain an understanding of the complex interactions between the physical phenomena involved, with particular attention to the effects of buoyancy on the turbulence structure, flame behavior, and factors influencing flame extinction.

Cellular Assays for Ferredoxins: A Strategy for Understanding Electron Flow through Protein Carriers That Link Metabolic Pathways.

PubMed

Atkinson, Joshua T; Campbell, Ian; Bennett, George N; Silberg, Jonathan J

2016-12-27

The ferredoxin (Fd) protein family is a structurally diverse group of iron-sulfur proteins that function as electron carriers, linking biochemical pathways important for energy transduction, nutrient assimilation, and primary metabolism. While considerable biochemical information about individual Fd protein electron carriers and their reactions has been acquired, we cannot yet anticipate the proportion of electrons shuttled between different Fd-partner proteins within cells using biochemical parameters that govern electron flow, such as holo-Fd concentration, midpoint potential (driving force), molecular interactions (affinity and kinetics), conformational changes (allostery), and off-pathway electron leakage (chemical oxidation). Herein, we describe functional and structural gaps in our Fd knowledge within the context of a sequence similarity network and phylogenetic tree, and we propose a strategy for improving our understanding of Fd sequence-function relationships. We suggest comparing the functions of divergent Fds within cells whose growth, or other measurable output, requires electron transfer between defined electron donor and acceptor proteins. By comparing Fd-mediated electron transfer with biochemical parameters that govern electron flow, we posit that models that anticipate energy flow across Fd interactomes can be built. This approach is expected to transform our ability to anticipate Fd control over electron flow in cellular settings, an obstacle to the construction of synthetic electron transfer pathways and rational optimization of existing energy-conserving pathways.

The compositional and evolutionary logic of metabolism

NASA Astrophysics Data System (ADS)

Braakman, Rogier; Smith, Eric

2013-02-01

Metabolism is built on a foundation of organic chemistry, and employs structures and interactions at many scales. Despite these sources of complexity, metabolism also displays striking and robust regularities in the forms of modularity and hierarchy, which may be described compactly in terms of relatively few principles of composition. These regularities render metabolic architecture comprehensible as a system, and also suggests the order in which layers of that system came into existence. In addition metabolism also serves as a foundational layer in other hierarchies, up to at least the levels of cellular integration including bioenergetics and molecular replication, and trophic ecology. The recapitulation of patterns first seen in metabolism, in these higher levels, motivates us to interpret metabolism as a source of causation or constraint on many forms of organization in the biosphere. Many of the forms of modularity and hierarchy exhibited by metabolism are readily interpreted as stages in the emergence of catalytic control by living systems over organic chemistry, sometimes recapitulating or incorporating geochemical mechanisms. We identify as modules, either subsets of chemicals and reactions, or subsets of functions, that are re-used in many contexts with a conserved internal structure. At the small molecule substrate level, module boundaries are often associated with the most complex reaction mechanisms, catalyzed by highly conserved enzymes. Cofactors form a biosynthetically and functionally distinctive control layer over the small-molecule substrate. The most complex members among the cofactors are often associated with the reactions at module boundaries in the substrate networks, while simpler cofactors participate in widely generalized reactions. The highly tuned chemical structures of cofactors (sometimes exploiting distinctive properties of the elements of the periodic table) thereby act as ‘keys’ that incorporate classes of organic reactions within biochemistry. Module boundaries provide the interfaces where change is concentrated, when we catalogue extant diversity of metabolic phenotypes. The same modules that organize the compositional diversity of metabolism are argued, with many explicit examples, to have governed long-term evolution. Early evolution of core metabolism, and especially of carbon-fixation, appears to have required very few innovations, and to have used few rules of composition of conserved modules, to produce adaptations to simple chemical or energetic differences of environment without diverse solutions and without historical contingency. We demonstrate these features of metabolism at each of several levels of hierarchy, beginning with the small-molecule metabolic substrate and network architecture, continuing with cofactors and key conserved reactions, and culminating in the aggregation of multiple diverse physical and biochemical processes in cells.

Gender-related power differences, beliefs and reactions towards people living with HIV/AIDS: an urban study in Nigeria.

PubMed

Mbonu, Ngozi C; Van den Borne, Bart; De Vries, Nanne K

2010-06-12

Although there are an increasing number of studies on HIV-related stigma in Nigeria, very little research has focused on how power differences based on gender perpetuate the stigmatization of people living with HIV/AIDS (PLWHA) and how these gender differences affect the care that PLWHA receive in health care institutions. We explore gender-related beliefs and reactions of society, including health care professionals (HCPs), with regard to PLWHA, using Connell's theoretical framework of gender and power (1987). With Connell's structural theory of gender and power (financial inequality, authority and structure of social norms), we can describe gender differences in stigmatization of PLWHA. We conducted in-depth semi-structured interviews, lasting 60 to 90 minutes, with 100 persons (40 members of the general public, 40 HCPs and 20 PLWHA) in Port Harcourt, Nigeria. The interviews were tape-recorded and transcribed verbatim. The Nvivo 7 computer package was used to analyze the data. There are similarities and differences between the general public and HCPs towards PLWHA in gender-related beliefs and reactions. For instance, although association with promiscuity and power differences were commonly acknowledged in the different groups, there are differences in how these reactions are shown; such as HCPs asking the female PLWHA to inform their partners to ensure payment of hospital bills. Women with HIV/AIDS in particular are therefore in a disadvantaged position with regard to the care they receive. Despite the fact that men and women with HIV/AIDS suffer the same illness, clear disparities are apparent in the negative reaction women and men living with HIV/AIDS experience in society. We show that women's generally low status in society contributes to the extreme negative reactions to which female PLWHA are subject. The government should create policies aimed at reducing the power differences in family, society and health care systems, which would be important to decrease the gender-related differences in stigma experienced by PLWHA. Interventions should be directed at the prevailing societal norms through appropriate legislation and advocacy at grassroots level with the support of men to counter laws that put women in a disadvantaged position. Furthermore, development of a policy that encourages equality in access to health care for all patients with HIV/AIDS by applying the same conditions to both men and women in health care institutions is recommended. There is a need to protect women's rights through implementing support policies, including paying attention to gender in the training of HCPs.

Gender-related power differences, beliefs and reactions towards people living with HIV/AIDS: an urban study in Nigeria

PubMed Central

2010-01-01

Background Although there are an increasing number of studies on HIV-related stigma in Nigeria, very little research has focused on how power differences based on gender perpetuate the stigmatization of people living with HIV/AIDS (PLWHA) and how these gender differences affect the care that PLWHA receive in health care institutions. We explore gender-related beliefs and reactions of society, including health care professionals (HCPs), with regard to PLWHA, using Connell's theoretical framework of gender and power (1987). With Connell's structural theory of gender and power (financial inequality, authority and structure of social norms), we can describe gender differences in stigmatization of PLWHA. Method We conducted in-depth semi-structured interviews, lasting 60 to 90 minutes, with 100 persons (40 members of the general public, 40 HCPs and 20 PLWHA) in Port Harcourt, Nigeria. The interviews were tape-recorded and transcribed verbatim. The Nvivo 7 computer package was used to analyze the data. Results There are similarities and differences between the general public and HCPs towards PLWHA in gender-related beliefs and reactions. For instance, although association with promiscuity and power differences were commonly acknowledged in the different groups, there are differences in how these reactions are shown; such as HCPs asking the female PLWHA to inform their partners to ensure payment of hospital bills. Women with HIV/AIDS in particular are therefore in a disadvantaged position with regard to the care they receive. Conclusion Despite the fact that men and women with HIV/AIDS suffer the same illness, clear disparities are apparent in the negative reaction women and men living with HIV/AIDS experience in society. We show that women's generally low status in society contributes to the extreme negative reactions to which female PLWHA are subject. The government should create policies aimed at reducing the power differences in family, society and health care systems, which would be important to decrease the gender-related differences in stigma experienced by PLWHA. Interventions should be directed at the prevailing societal norms through appropriate legislation and advocacy at grassroots level with the support of men to counter laws that put women in a disadvantaged position. Furthermore, development of a policy that encourages equality in access to health care for all patients with HIV/AIDS by applying the same conditions to both men and women in health care institutions is recommended. There is a need to protect women's rights through implementing support policies, including paying attention to gender in the training of HCPs. PMID:20540794

A structuration framework for bridging the macro-micro divide in health-care governance.

PubMed

Bodolica, Virginia; Spraggon, Martin; Tofan, Gabriela

2016-08-01

Extant studies demonstrate that macro (hierarchical) and micro (relational) governance initiatives in health-care settings continue to be developed in isolation rather than interactively. Government-driven hierarchical governance endeavours that guide health-care reforms and medical practice are disconnected from micro-level physician-patient interactions being unable to account for patient preferences in the macro-level policymaking. We undertake a review of the recent literature to couch our argument for a unified governance framework for bridging the macro-micro divide in medical contexts. Adopting an interdisciplinary approach to health-care delivery, we maintain that the (strong) structuration theory provides a fruitful opportunity for narrowing the gap between hierarchical and relational governance. Emphasizing the coexistence of institutional structures and human agency, the (strong) structuration theory elucidates how macro and micro governance devices shape each other's structure via mutually reinforcing cycles of influence. Micro-level encounters between patients and physicians give rise to social structures that constitute the constraining and enabling forces through which macro-level health-care infrastructures are altered and reproduced over time. Permitting to illustrate how patients' agency can effectively emerge from complex networks of clinical trajectories, the advanced structuration framework for macro-micro governance integration avoids the extremes of paternalism and autonomy through a balanced consideration of professional judgement and patient preferences. The macro-micro integration of governance efforts is a critical issue in both high-income states, where medical institutions attempt to deploy substantial realignment efforts, and developing nations, which are lagging behind due to leadership weaknesses and lower levels of governmental investment. A key priority for regulators is the identification of relevant systems to support this holistic governance by providing clinicians with needed resources for focusing on patient advocacy and installing enabling mechanisms for incorporating patients' inputs in health-care reforms and policymaking. © 2015 John Wiley & Sons Ltd.

Oil on the water: Government regulation of a carcinogen in the twentieth-century Lancashire cotton spinning industry.

PubMed

Higgins, David; Tweedale, Geoffrey

2010-01-01

In the Lancashire cotton textile industry, mule spinners were prone to a chronic and sometimes fatal skin cancer (often affecting the groin). The disease had reached epidemic proportions by the 1920s, which necessitated action by the government, employers, and trade unions. In contrast to previous accounts, this article focuses on the government's reaction to mule spinners' cancer. Using official records in the National Archives, the slow introduction of health and safety measures by the government is explored in detail. Although obstructionism by the employers played a key role, one of the reasons for government inaction was the ambiguity of scientific research on engineering oils. On the other hand, prolonged scientific research suited a government policy that was framed around self regulation - a policy that had proved largely ineffective by the 1950s.

Understanding public reactions to commercialization of biobanks and use of biobank resources.

PubMed

Nicol, Dianne; Critchley, Christine; McWhirter, Rebekah; Whitton, Tess

2016-08-01

Biobanks will be essential to facilitate the translation of genomic research into real improvements to healthcare. Biobanking is a long-term commitment, requiring public support as well as appropriate regulatory, social and ethical guidelines to realize this promise. There is a growing body of research that explores the necessary conditions to ensure public trust in biomedical research, particularly in the context of biobanking. Trust is, however, a complex relationship. More analysis of public perceptions, attitudes and reactions is required to understand the primary triggers that influence gain and loss of trust. Further, the outcomes of these analyses require detailed consideration to determine how to promote trustworthy institutions and practices. This article uses national survey data, combined with the results of a community consultation that took place in Tasmania, Australia in 2013, to analyze the specific issue of public reactions to commercialization of biobanks and their outputs. This research will enhance the ability of biobanks to respond preemptively to public concerns about commercialization by establishing and maintaining governance frameworks that are responsive to those concerns. The results reveal that it is possible to counter the 'natural prejudice' that many people have against commercialization through independent governance of biobank resources and transparency with regard to commercial involvement. Indeed, most participants agreed that they would rather have a biobank with commercial involvement than none at all. This analysis provides nuanced conclusions about public reactions towards commercialization and equips researchers and biobank operators with data on which to base policies and make governance decisions in order to tackle participant concerns respectfully and responsively. Copyright © 2016 Elsevier Ltd. All rights reserved.

Governing board structure, business strategy, and performance of acute care hospitals: a contingency perspective.

PubMed Central

Young, G; Beekun, R I; Ginn, G O

1992-01-01

Contingency theory suggests that for a hospital governing board to be effective in taking on a more active role in strategic management, the board needs to be structured to complement the overall strategy of the organization. A survey study was conducted to examine the strategies of acute care hospitals as related to the structural characteristics of their governing boards. After controlling for organizational size and system membership, results indicated a significant relationship between the governing board structure of 109 acute care hospitals and their overall business strategy. Strategy also accounted for more of the variance in board structure than either organization size or system membership. Finally, the greater the match between board structure and hospital strategy, the stronger the hospitals' financial performance. PMID:1399656

Organic aerogel microspheres

DOEpatents

Mayer, S.T.; Kong, F.M.; Pekala, R.W.; Kaschmitter, J.L.

1999-06-01

Organic aerogel microspheres are disclosed which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonstick gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

Organic aerogel microspheres

DOEpatents

Mayer, Steven T.; Kong, Fung-Ming; Pekala, Richard W.; Kaschmitter, James L.

1999-01-01

Organic aerogel microspheres which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonsticky gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

Organic aerogel microspheres and fabrication method therefor

DOEpatents

Mayer, S.T.; Kong, F.M.; Pekala, R.W.; Kaschmitter, J.L.

1996-04-16

Organic aerogel microspheres which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonsticky gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

Organic aerogel microspheres and fabrication method therefor

DOEpatents

Mayer, Steven T.; Kong, Fung-Ming; Pekala, Richard W.; Kaschmitter, James L.

1996-01-01

Organic aerogel microspheres which can be used in capacitors, batteries, thermal insulation, adsorption/filtration media, and chromatographic packings, having diameters ranging from about 1 micron to about 3 mm. The microspheres can be pyrolyzed to form carbon aerogel microspheres. This method involves stirring the aqueous organic phase in mineral oil at elevated temperature until the dispersed organic phase polymerizes and forms nonsticky gel spheres. The size of the microspheres depends on the collision rate of the liquid droplets and the reaction rate of the monomers from which the aqueous solution is formed. The collision rate is governed by the volume ratio of the aqueous solution to the mineral oil and the shear rate, while the reaction rate is governed by the chemical formulation and the curing temperature.

Development and evaluation of epoxidized soybean oil-based polymers

NASA Astrophysics Data System (ADS)

Juangvanich, Nuanpen

Epoxidized Soybean Oil (ESO) based polymers were developed using diamine curing agents and BF3:NH2C2H5 as catalyst. Reactions involved the curing process were explored and monitored by DSC and IR analysis. Amine-epoxy addition reactions governed the main curing reaction at the temperature range of 60--235°C, and the supplementary reactions at higher temperatures were either homopolymerization or etherification reaction. In the aliphatic curing reactions, the epoxy-rich system favored the supplementary reactions at high temperature, however, ESO cured with 1,6 hexanediamine (HDA) always produced the high temperature reaction products, due to some side reactions and the high volatile nature. The curing reaction with aromatic diamines produced inherent rigidity to the cured ESO network, which decreased the high temperature reactions. The system cured with a short aromatic diamine, 1,4-phenyldiamine (PDA), produced a small extent of high temperature reaction, as well. It was believed that the long length diamine with wide separation of the two amines underwent an intermolecular cross-linking reaction, and derived better properties than the shorter diamine. A post-cure process was used to improve the final polymer properties by increasing the temperature after the initial curing reaction was quenched due to gelation. Extending the time of post-curing did not significantly improve properties of the final ESO polymers. Exposing the cured samples at 180°C for longer than 12 hours decreased the properties of the cured material, due to thermal strain generating in the network structure. To increase time efficiency, short heat cycles were performed by post-curing right after gelation, and the cured ESO polymer had tensile strength of 32 MPa, modulus 750 MPa and toughness 1.3 MPa. With the introduction of EPON 828, the mechanical properties of a new ESO polymer improved; having strength above 40 MPa, modulus great than 1,000 MPa, and Tg higher than 40°C. Finally, a rice hull particleboard was developed using the cured ESO resin as adhesive, and the board had strength comparable to the National Bureau of Standards minimum requirement for particleboard. A 35 wt % of ESO resin imparted the highest strength for the rice hull board, with a value of 15.5 MPa.

Role of innovative institutional structures in integrated governance. A case study of integrating health and nutrition programs in Chhattisgarh, India.

PubMed

Kalita, Anuska; Mondal, Shinjini

2012-01-01

The aim of this paper is to highlight the significance of integrated governance in bringing about community participation, improved service delivery, accountability of public systems and human resource rationalisation. It discusses the strategies of innovative institutional structures in translating such integration in the areas of public health and nutrition for poor communities. The paper draws on experience of initiating integrated governance through innovations in health and nutrition programming in the resource-poor state of Chhattisgarh, India, at different levels of governance structures--hamlets, villages, clusters, blocks, districts and at the state. The study uses mixed methods--i.e. document analysis, interviews, discussions and quantitative data from facilities surveys--to present a case study analyzing the process and outcome of integration. The data indicate that integrated governance initiatives improved convergence between health and nutrition departments of the state at all levels. Also, innovative structures are important to implement the idea of integration, especially in contexts that do not have historical experience of such partnerships. Integration also contributed towards improved participation of communities in self-governance, community monitoring of government programs, and therefore, better services. As governments across the world, especially in developing countries, struggle towards achieving better governance, integration can serve as a desirable process to address this. Integration can affect the decentralisation of power, inclusion, efficiency, accountability and improved service quality in government programs. The institutional structures detailed in this paper can provide models for replication in other similar contexts for translating and sustaining the idea of integrated governance. This paper is one of the few to investigate innovative public institutions of a and community mobilisation to explore this important, and under-researched, topic.

Aboriginal and Torres Strait Islander community governance of health research: Turning principles into practice.

PubMed

Gwynn, Josephine; Lock, Mark; Turner, Nicole; Dennison, Ray; Coleman, Clare; Kelly, Brian; Wiggers, John

2015-08-01

Gaps exist in researchers' understanding of the 'practice' of community governance in relation to research with Aboriginal and Torres Strait Islander peoples. We examine Aboriginal community governance of two rural NSW research projects by applying principles-based criteria from two independent sources. One research project possessed a strong Aboriginal community governance structure and evaluated a 2-year healthy lifestyle program for children; the other was a 5-year cohort study examining factors influencing the mental health and well-being of participants. The National Health and Medical Research Council of Australia's 'Values and ethics: guidelines for ethical conduct in Aboriginal and Torres Strait Islander research' and 'Ten principles relevant to health research among Indigenous Australian populations' described by experts in the field. Adopt community-based participatory research constructs. Develop clear governance structures and procedures at the beginning of the study and allow sufficient time for their establishment. Capacity-building must be a key component of the research. Ensure sufficient resources to enable community engagement, conduct of research governance procedures, capacity-building and results dissemination. The implementation of governance structures and procedures ensures research addresses the priorities of the participating Aboriginal and Torres Strait Islander communities, minimises risks and improves outcomes for the communities. Principles-based Aboriginal and Torres Strait Islander community governance of research is very achievable. Next steps include developing a comprehensive evidence base for appropriate governance structures and procedures, and consolidating a suite of practical guides for structuring clear governance in health research. © 2015 National Rural Health Alliance Inc.

Liquid-assisted grinding and ion pairing regulates percentage conversion and diastereoselectivity of the Wittig reaction under mechanochemical conditions.

PubMed

Denlinger, Kendra Leahy; Ortiz-Trankina, Lianna; Carr, Preston; Benson, Kingsley; Waddell, Daniel C; Mack, James

2018-01-01

Mechanochemistry is maturing as a discipline and continuing to grow, so it is important to continue understanding the rules governing the system. In a mechanochemical reaction, the reactants are added into a vessel along with one or more grinding balls and the vessel is shaken at high speeds to facilitate a chemical reaction. The dielectric constant of the solvent used in liquid-assisted grinding (LAG) and properly chosen counter-ion pairing increases the percentage conversion of stilbenes in a mechanochemical Wittig reaction. Utilizing stepwise addition/evaporation of ethanol in liquid-assisted grinding also allows for the tuning of the diastereoselectivity in the Wittig reaction.

Analytic Modeling of the Hydrodynamic, Thermal, and Structural Behavior of Foil Thrust Bearings

NASA Technical Reports Server (NTRS)

Bruckner, Robert J.; DellaCorte, Christopher; Prahl, Joseph M.

2005-01-01

A simulation and modeling effort is conducted on gas foil thrust bearings. A foil bearing is a self acting hydrodynamic device capable of separating stationary and rotating components of rotating machinery by a film of air or other gaseous lubricant. Although simple in appearance these bearings have proven to be complicated devices in analysis. They are sensitive to fluid structure interaction, use a compressible gas as a lubricant, may not be in the fully continuum range of fluid mechanics, and operate in the range where viscous heat generation is significant. These factors provide a challenge to the simulation and modeling task. The Reynolds equation with the addition of Knudsen number effects due to thin film thicknesses is used to simulate the hydrodynamics. The energy equation is manipulated to simulate the temperature field of the lubricant film and combined with the ideal gas relationship, provides density field input to the Reynolds equation. Heat transfer between the lubricant and the surroundings is also modeled. The structural deformations of the bearing are modeled with a single partial differential equation. The equation models the top foil as a thin, bending dominated membrane whose deflections are governed by the biharmonic equation. A linear superposition of hydrodynamic load and compliant foundation reaction is included. The stiffness of the compliant foundation is modeled as a distributed stiffness that supports the top foil. The system of governing equations is solved numerically by a computer program written in the Mathematica computing environment. Representative calculations and comparisons with experimental results are included for a generation I gas foil thrust bearing.

Consent and Dissent: A Study of the Reaction of Chinese School Teachers in Guangzhou City Schools to Government Educational Reforms

ERIC Educational Resources Information Center

Seifert, Roger; Li, Yingfei

2014-01-01

This paper presents detailed qualitative evidence from a case study of teachers in five Chinese schools in one city. It explicitly seeks to show how developments in government policy towards education have altered the management of teacher labour inside schools as well as the teacher labour process as expressed by the teachers themselves in…

Prediction and characterization of heat-affected zone formation in tin-bismuth alloys due to nickel-aluminum multilayer foil reaction

DOE PAGES

Hooper, R. J.; Davis, C. G.; Johns, P. M.; ...

2015-06-26

Reactive multilayer foils have the potential to be used as local high intensity heat sources for a variety of applications. In this study, most of the past research effort concerning these materials have focused on understanding the structure-property relationships of the foils that govern the energy released during a reaction. To improve the ability of researchers to more rapidly develop technologies based on reactive multilayer foils, a deeper and more predictive understanding of the relationship between the heat released from the foil and microstructural evolution in the neighboring materials is needed. This work describes the development of a numerical modelmore » for the purpose of predicting heat affected zone size in substrate materials. The model is experimentally validated using a commercially available Ni-Al multilayer foils and alloys from the Sn-Bi binary system. To accomplish this, phenomenological models for predicting the variation of physical properties (i.e., thermal conductivity, density, and heat capacity) with temperature and composition in the Sn-Bi system were utilized using literature data.« less

Theory of First Order Chemical Kinetics at the Critical Point of Solution.

PubMed

Baird, James K; Lang, Joshua R

2017-10-26

Liquid mixtures, which have a phase diagram exhibiting a miscibility gap ending in a critical point of solution, have been used as solvents for chemical reactions. The reaction rate in the forward direction has often been observed to slow down as a function of temperature in the critical region. Theories based upon the Gibbs free energy of reaction as the driving force for chemical change have been invoked to explain this behavior. With the assumption that the reaction is proceeding under relaxation conditions, these theories expand the free energy in a Taylor series about the position of equilibrium. Since the free energy is zero at equilibrium, the leading term in the Taylor series is proportional to the first derivative of the free energy with respect to the extent of reaction. To analyze the critical behavior of this derivative, the theories exploit the principle of critical point isomorphism, which is thought to govern all critical phenomena. They find that the derivative goes to zero in the critical region, which accounts for the slowing down observed in the reaction rate. As has been pointed out, however, most experimental rate investigations have been carried out under irreversible conditions as opposed to relaxation conditions [Shen et al. J. Phys. Chem. A 2015, 119, 8784-8791]. Below, we consider a reaction governed by first order kinetics and invoke transition state theory to take into account the irreversible conditions. We express the apparent activation energy in terms of thermodynamic derivatives evaluated under standard conditions as well as the pseudoequilibrium conditions associated with the reactant and the activated complex. We show that these derivatives approach infinity in the critical region. The apparent activation energy follows this behavior, and its divergence accounts for the slowing down of the reaction rate.

Global constitutionalism, applied to global health governance: uncovering legitimacy deficits and suggesting remedies.

PubMed

Ooms, Gorik; Hammonds, Rachel

2016-12-03

Global constitutionalism is a way of looking at the world, at global rules and how they are made, as if there was a global constitution, empowering global institutions to act as a global government, setting rules which bind all states and people. This essay employs global constitutionalism to examine how and why global health governance, as currently structured, has struggled to advance the right to health, a fundamental human rights obligation enshrined in the International Covenant on Economic, Social and Cultural Rights. It first examines the core structure of the global health governance architecture, and its evolution since the Second World War. Second, it identifies the main constitutionalist principles that are relevant for a global constitutionalism assessment of the core structure of the global health governance architecture. Finally, it applies these constitutionalist principles to assess the core structure of the global health governance architecture. Leading global health institutions are structurally skewed to preserve high incomes countries' disproportionate influence on transnational rule-making authority, and tend to prioritise infectious disease control over the comprehensive realisation of the right to health. A Framework Convention on Global Health could create a classic division of powers in global health governance, with WHO as the law-making power in global health governance, a global fund for health as the executive power, and the International Court of Justice as the judiciary power.

Government-Sponsored Programs on Structures Technology

NASA Technical Reports Server (NTRS)

Noor, Ahmed K. (Compiler); Malone, John B. (Compiler)

1997-01-01

This document contains the presentations from the joint UVA/AIAA workshops on Government-Sponsored Programs on Structures Technology, held on April 6, 1997 in Kissimmee, Florida and on September 4, 1997 in Hampton, Virginia. Workshop attendees were the Members and Friends of the AIAA Structures Technical Committee. The objectives of the workshops were to: (a) provide a forum for discussion of current government-sponsored programs in the structures area; (b) identify high-potential research areas for future aerospace systems; and (c) initiate suitable interaction mechanisms with the managers of structures programs.

Reactions of small organic molecules on silver(110)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ayre, C.R.

1992-01-01

The interaction of two pairs of molecules (1) acetone (CH[sub 3])[sub 2]C=O and isobutylene (CH[sub 3])[sub 2] C=CH[sub 2] and (2) 1,2-propanediol CH[sub 3] CH (OH)CH[sub 2]OH and 1,3-propanediol HOCH[sub 2]CH[sub 2]CH[sub 2]OH with clean and oxygen-activated Ag(110) has been explored to investigate the effects of molecular structure on reactivity. Experimental techniques employed include temperature programmed reaction spectroscopy, isotopic labelling, surface displacement reactions, and electron energy loss spectroscopy. Acetone and isobutylene were studied to explore the relative importance of C=O and C=C bonds in governing the reactivity of structurally similar compounds. Nucleophilic attack by oxygen at the electron-deficient carbonyl carbonmore » in acetone results in reversible formation of the metallacycle (CH[sub 3])[sub 2]COO[sub (a)] at 110 K. Upon heating C-H bond activation by O[sub (a)] occurs near 215 K to yield acetone enolate CH[sub 2]=C(CH[sub 3])O[sub (a)] and evolve H[sub 2]O[sub (g)]. Atomic oxygen activates methyl C-H bonds in isobutylene via an acid-base mechanism. Although the major products are CO[sub 2(g)] and H[sub 2]O[sub (g)], a small amount of (CH[sub 3])[sub 2]C=CH[sub 2(g)] evolves near 310 K. Evidence for the formation of [pi]-2-methylallyl CH[sub 3]C(CH[sub 2])[sub 2(a)] and trimethylenementhane C(CH[sub 2])[sub 3(a)] is presented. The reaction of 1,2-propanediol CH[sub 3] CH(OH)CH[sub 2] OH with oxygen-activated Ag(110) has been compared with that of 1,3-propanediol HOCH[sub 2]CH[sub 2]CH[sub 2]OH to evaluate the effects of varying the position of O-H bonds in both diols to produce the corresponding dialkoxides.« less

Osmium Tag for Posttranscriptionally Modified RNA.

PubMed

Debnath, Turja Kanti; Okamoto, Akimitsu

2018-05-25

Nucleotide modifications of cellular RNA are highly abundant and diverse, but their origin and functions have not yet been investigated. 5-Methylcytidine (m5C) and 5-methyluridine (m5U) are highly abundant posttranscriptionally modified nucleotides observed in various natural RNAs. Such nucleotides have been labeled through a chemical approach as both undergo oxidation at the C5-C6 double bond, leading to the formation of osmium-bipyridine complexes, which are identified by mass spectrometry. This osmium tag made it possible to distinguished m5C and m5U from their isomers 2'-O-methylcytidine and 2'-O-methyluridine, respectively. Queuosine and 2-methylthio-N6-isopentenyladenosine in tRNA were also tagged through this complex formation--this is the first time that this has ever been achieved. Osmylation has emerged as a structure-selective reaction and largely governed by the environment of the target site (the steric and higher order structure), therefore it could be helpful for studying the structure and dynamics of RNA-protein interactions. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Supramolecular "Step Polymerization" of Preassembled Micelles: A Study of "Polymerization" Kinetics.

PubMed

Yang, Chaoying; Ma, Xiaodong; Lin, Jiaping; Wang, Liquan; Lu, Yingqing; Zhang, Liangshun; Cai, Chunhua; Gao, Liang

2018-03-01

In nature, sophisticated functional materials are created through hierarchical self-assembly of nanoscale motifs, which has inspired the fabrication of man-made materials with complex architectures for a variety of applications. Herein, a kinetic study on the self-assembly of spindle-like micelles preassembled from polypeptide graft copolymers is reported. The addition of dimethylformamide and, subsequently, a selective solvent (water) can generate a "reactive point" at both ends of the spindles as a result of the existence of structural defects, which induces the "polymerization" of the spindles into nanowires. Experimental results combined with dissipative particle dynamics simulations show that the polymerization of the micellar subunits follows a step-growth polymerization mechanism with a second-order reaction characteristic. The assembly rate of the micelles is dependent on the subunit concentration and on the activity of the reactive points. The present work reveals a law governing the self-assembly kinetics of micelles with structural defects and opens the door for the construction of hierarchical structures with a controllable size through supramolecular step polymerization. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Atomistic Structure of Mineral Nano-aggregates from Simulated Compaction and Dewatering.

PubMed

Ho, Tuan Anh; Greathouse, Jeffery A; Wang, Yifeng; Criscenti, Louise J

2017-11-10

The porosity of clay aggregates is an important property governing chemical reactions and fluid flow in low-permeability geologic formations and clay-based engineered barrier systems. Pore spaces in clays include interlayer and interparticle pores. Under compaction and dewatering, the size and geometry of such pore spaces may vary significantly (sub-nanometer to microns) depending on ambient physical and chemical conditions. Here we report a molecular dynamics simulation method to construct a complex and realistic clay-like nanoparticle aggregate with interparticle pores and grain boundaries. The model structure is then used to investigate the effect of dewatering and water content on micro-porosity of the aggregates. The results suggest that slow dewatering would create more compact aggregates compared to fast dewatering. Furthermore, the amount of water present in the aggregates strongly affects the particle-particle interactions and hence the aggregate structure. Detailed analyses of particle-particle and water-particle interactions provide a molecular-scale view of porosity and texture development of the aggregates. The simulation method developed here may also aid in modeling the synthesis of nanostructured materials through self-assembly of nanoparticles.

Atomistic Structure of Mineral Nano-aggregates from Simulated Compaction and Dewatering

DOE PAGES

Ho, Tuan Anh; Greathouse, Jeffery A.; Wang, Yifeng; ...

2017-11-10

The porosity of clay aggregates is an important property governing chemical reactions and fluid flow in low-permeability geologic formations and clay-based engineered barrier systems. Pore spaces in clays include interlayer and interparticle pores. Under compaction and dewatering, the size and geometry of such pore spaces may vary significantly (sub-nanometer to microns) depending on ambient physical and chemical conditions. Here we report a molecular dynamics simulation method to construct a complex and realistic clay-like nanoparticle aggregate with interparticle pores and grain boundaries. The model structure is then used to investigate the effect of dewatering and water content on micro-porosity of themore » aggregates. The results suggest that slow dewatering would create more compact aggregates compared to fast dewatering. Furthermore, the amount of water present in the aggregates strongly affects the particle-particle interactions and hence the aggregate structure. Detailed analyses of particle-particle and water-particle interactions provide a molecular-scale view of porosity and texture development of the aggregates. The simulation method developed here may also aid in modeling the synthesis of nanostructured materials through self-assembly of nanoparticles.« less

Synthesis-driven, structure-dependent optical behavior in phase-tunable NaYF 4:Yb,Er-based motifs and associated heterostructures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Haiqing; Han, Jinkyu; McBean, Coray

Understanding the key parameters necessary for generating uniform Er,Yb co-activated NaYF 4 possessing various selected phases (i.e. cubic or hexagonal) represents an important chemical strategy towards tailoring optical behavior in these systems. In this paper, we report on a straightforward hydrothermal synthesis in which the separate effects of reaction temperature, reaction time, and precursor stoichiometry in the absence of any surfactant were independently investigated. Interestingly, the presence and the concentration of NH 4OH appear to be the most critical determinants of the phase and morphology. For example, with NH 4OH as an additive, we have observed the formation of novelmore » hierarchical nanowire bundles which possess overall lengths of ~5 μm and widths of ~1.5 μm but are composed of constituent component sub-units of long, ultrathin (~5 nm) nanowires. These motifs have yet to be reported as distinctive morphological manifestations of fluoride materials. The optical properties of as-generated structures have also been carefully analyzed. Specifically, we have observed tunable, structure-dependent energy transfer behavior associated with the formation of a unique class of NaYF 4–CdSe quantum dot (QD) heterostructures, incorporating zero-dimensional (0D), one-dimensional (1D), and three-dimensional (3D) NaYF 4 structures. Our results have demonstrated the key roles of the intrinsic morphology-specific physical surface area and porosity as factors in governing the resulting opto-electronic behavior. Finally and specifically, the trend in energy transfer efficiency correlates well with the corresponding QD loading within these heterostructures, thereby implying that the efficiency of FRET appears to be directly affected by the amount of QDs immobilized onto the external surfaces of the underlying fluoride host materials.« less

Synthesis-driven, structure-dependent optical behavior in phase-tunable NaYF 4:Yb,Er-based motifs and associated heterostructures

DOE PAGES

Liu, Haiqing; Han, Jinkyu; McBean, Coray; ...

2017-01-03

Understanding the key parameters necessary for generating uniform Er,Yb co-activated NaYF 4 possessing various selected phases (i.e. cubic or hexagonal) represents an important chemical strategy towards tailoring optical behavior in these systems. In this paper, we report on a straightforward hydrothermal synthesis in which the separate effects of reaction temperature, reaction time, and precursor stoichiometry in the absence of any surfactant were independently investigated. Interestingly, the presence and the concentration of NH 4OH appear to be the most critical determinants of the phase and morphology. For example, with NH 4OH as an additive, we have observed the formation of novelmore » hierarchical nanowire bundles which possess overall lengths of ~5 μm and widths of ~1.5 μm but are composed of constituent component sub-units of long, ultrathin (~5 nm) nanowires. These motifs have yet to be reported as distinctive morphological manifestations of fluoride materials. The optical properties of as-generated structures have also been carefully analyzed. Specifically, we have observed tunable, structure-dependent energy transfer behavior associated with the formation of a unique class of NaYF 4–CdSe quantum dot (QD) heterostructures, incorporating zero-dimensional (0D), one-dimensional (1D), and three-dimensional (3D) NaYF 4 structures. Our results have demonstrated the key roles of the intrinsic morphology-specific physical surface area and porosity as factors in governing the resulting opto-electronic behavior. Finally and specifically, the trend in energy transfer efficiency correlates well with the corresponding QD loading within these heterostructures, thereby implying that the efficiency of FRET appears to be directly affected by the amount of QDs immobilized onto the external surfaces of the underlying fluoride host materials.« less

An abnormally slow proton transfer reaction in a simple HBO derivative due to ultrafast intramolecular-charge transfer events.

PubMed

Alarcos, Noemí; Gutierrez, Mario; Liras, Marta; Sánchez, Félix; Douhal, Abderrazzak

2015-07-07

We report on the steady-state, picosecond and femtosecond time-resolved studies of a charge and proton transfer dye 6-amino-2-(2'-hydroxyphenyl)benzoxazole (6A-HBO) and its methylated derivative 6-amino-2-(2'-methoxyphenyl)benzoxazole (6A-MBO), in different solvents. With femtosecond resolution and comparison with the photobehaviour of 6A-MBO, we demonstrate for 6A-HBO in solution, the photoproduction of an intramolecular charge-transfer (ICT) process at S1 taking place in ∼140 fs or shorter, followed by solvent relaxation in the charge transferred species. The generated structure (syn-enol charge transfer conformer) experiences an excited-state intramolecular proton-transfer (ESIPT) reaction to produce a keto-type tautomer. This subsequent proton motion occurs in 1.2 ps (n-heptane), 14 ps (DCM) and 35 ps (MeOH). In MeOH, it is assisted by the solvent molecules and occurs through tunneling for which we got a large kinetic isotope effect (KIE) of about 13. For the 6A-DBO (deuterated sample in CD3OD) the global proton-transfer reaction takes place in 200 ps, showing a remarkable slow KIE regime. The slow ESIPT reaction in DCM (14 ps), not through tunnelling as it is not sensitive to OH/OD exchange, has however to overcome an energy barrier using intramolecular as well as solvent coordinates. The rich ESIPT dynamics of 6A-HBO in the used solutions is governed by an ICT reaction, triggered by the amino group, and it is solvent dependent. Thus, the charge injection to a 6A-HBO molecular frame makes the ICT species more stable, and the phenol group less acidic, slowing down the subsequent ESIPT reaction. Our findings bring new insights into the coupling between ICT and ESIPT reactions on the potential-energy surfaces of several barriers.

Organizational Considerations for Implementing Systems Engineering and Integration in the Ares Projects Office

NASA Technical Reports Server (NTRS)

Thomas, LeAnn; Doreswamy, Rajiv N.

2008-01-01

Systems Engineering and Integration (SE&I) is a critical discipline in developing new space systems. In 2005, NASA performed an internal study of 24 agency and Department of Defense (DoD) programs to evaluate methods of integrating SE&I practices and determine their effectiveness. The goal of the study was to determine the best SE&I implementation strategy for the Ares Projects Office. The study identified six SE&I organizational structures: 1. Lead systems integrator (LSI) with SE&I responsibility and government technical insight. 2a. Integration contractor with government SE&I responsibility (government insight). 2b. Integration contractor with government SE&I responsibility (government oversight). 3a. Prime contractor with SE&I responsibility (government insight). 3b. Prime contractor with SE&I responsibility (government oversight). 3c. Prime contractor with SE&I responsibility (government/industry partnership). 4a.Prime contractor with government SE&I responsibility (government insight). 4b. Prime contractor with government SE&I responsibility (government oversight). 4d.Prime contractors with total system performance responsibility (TSPR). 5. Prime contractor with government SE&I responsibility and integration products through a Federally Funded Research and Development Center (FFRDC). 6. Government/FFRDC in-house development with SE&I responsibility and function. The organizational structure used most often was number 4, using a prime contractor with government SE&I responsibility and government technical insight. However, data analyses did not establish a positive relationship between program development costs and specific SE&I organizational types, nor did it positively determine the relationship between successful programs or projects and their SE&I structure. The SE&I study reached the following conclusions: (1) Large, long-duration, technically complex programs or projects reach their technical goals, but rarely meet schedule or cost goals. NASA's recent successes have been smaller, short-duration development projects using heritage hardware/software, focused technology development, technical oversight and stable external factors. (2) Programs and projects have failed or been terminated due to lack of technical insight, relaxing of SE&I processes, and unstable external factors. (3) The study did not find a single, clear optimum SE&I organization type to fit all projects. However, while any organizational structure can be made to work, the fewer complexities in the program, the better the likelihood of success. (4) The most common successful SE&I organization structure type in the study was type 4b, where the government maintained integration responsibility, with the prime contractor providing SE&I products and the government providing technical oversight. This study was instrumental in helping the APO select organization structure 4, following the same SE&I and oversight process used during humanlund7s last voyages to the Moon.

Relationship Governance and Learning in Partnerships

ERIC Educational Resources Information Center

Kohtamaki, Marko

2010-01-01

Purpose: Relationship learning is a topic of considerable importance for industrial networks, yet a lack of empirical research on the impact of relationship governance structures on relationship learning remains. The purpose of this paper is to analyze the impact of relationship governance structures on learning in partnerships.…

Nuclear Astrophysics at DANCE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Reifarth, R.; Bredeweg, T.A.; Esch, E.-I.

2005-05-24

One of the most interesting nuclear physics challenges is obtaining a detailed understanding of the nucleosynthesis processes of the elements. Knowledge about the stellar sites, and how they are governed by stellar evolution and cosmology are crucial in understanding the overall picture. Information on reaction rates for neutron- and charged-particle-induced reactions have a direct impact on existing stellar models. Except for the stable isotopes, very few neutron-induced reactions in the energy range of interest have been measured to date. DANCE measurements on stable and unstable isotopes will provide many of the missing key reactions that are needed to understand themore » nucleosynthesis of the heavy elements.« less

Experimental and theoretical studies of the products of addition-elimination reactions between benzil dihydrazone and three isomeric chlorobenzaldehydes.

PubMed

Liu, Yun-Na; Cheng, Shuang-Shuang; Wang, Chao; Xing, Dian-Xiang; Liu, Yun; Tan, Xue-Jie

2015-07-01

A series of mono- and di-Schiff bases formed between benzil dihydrazone {BDH; systematic name: (1Z)-[(2E)-2-hydrazinylidene-1,2-diphenylethylidene]hydrazine} and three isomeric chlorobenzaldehydes were designed and synthesized to be used as model compounds to help to explain the reaction mechanisms for the formation of Schiff bases. These compounds are 1-(2-chlorobenzylidene)-2-{2-[2-(2-chlorobenzylidene)hydrazin-1-ylidene]-1,2-diphenylethylidene}hydrazine (BDHOCB), and the 3-chloro (BDHMCB) and 4-chloro (BDHPCB) analogues, all having the formula C28H20Cl2N4. Surprisingly, only di-Schiff bases were obtained; our attempts to push the reaction in favour of the mono-Schiff bases all failed. Density functional theory (DFT) calculations were performed to explain the trend in the experimental results. In the case of the systems studied, the type of Schiff base produced exhibits a clear dependence on the HOMO-LUMO energy gaps (ΔE(HOMO-LUMO)), i.e. the product is mainly governed by its stability. The compounds were characterized by single-crystal X-ray diffractometry, elemental analysis, melting point, (1)H NMR and (13)C NMR spectroscopy. The structural features of the three new Schiff bases are similar. For instance, they have the same chemical formula, all the molecules have a symmetrical double helix structure, with each Ph-C=N-N=C-Ph arm exhibiting an anti conformation, and their supramolecular interactions include intermolecular π-π and weak C-H...π stacking interactions. The crystal systems are different, however, viz. triclinic (space group P1¯) for BDHPCB, monoclinic (space group P2(1)/n) for BDHOCB and orthorhombic (space group Pnna) for BDHMCB.

Factors Influencing the Selection of the Systems Integration Organizational Model Type for Planning and Implementing Government High-Technology Programs

NASA Technical Reports Server (NTRS)

Thomas, Leann; Utley, Dawn

2006-01-01

While there has been extensive research in defining project organizational structures for traditional projects, little research exists to support high technology government project s organizational structure definition. High-Technology Government projects differ from traditional projects in that they are non-profit, span across Government-Industry organizations, typically require significant integration effort, and are strongly susceptible to a volatile external environment. Systems Integration implementation has been identified as a major contributor to both project success and failure. The literature research bridges program management organizational planning, systems integration, organizational theory, and independent project reports, in order to assess Systems Integration (SI) organizational structure selection for improving the high-technology government project s probability of success. This paper will describe the methodology used to 1) Identify and assess SI organizational structures and their success rate, and 2) Identify key factors to be used in the selection of these SI organizational structures during the acquisition strategy process.

Outsourcing versus in-house maintenance of medical devices: a longitudinal, empirical study.

PubMed

Miguel-Cruz, Antonio; Rios-Rincón, Adriana; Haugan, Gregory L

2014-03-01

To determine what factors have a significant influence on the performance of medical device maintenance outsourcing, and to determine how the performance of external governance structures differs depending on whether a hospital is private or public. This was a longitudinal study of 590 maintenance transactions at 20 hospitals in Bogotá, Colombia, involving 764 medical devices and 72 maintenance service providers. Maintenance performance data (i.e., turn-around time in hours; TAT) for the service providers (either in-house or outsourced) were primarily collected over a 20-month period, from December 2009-August 2011, by means of a monitoring procedure; then, a hazards model was run. The availability of specific repair parts, in-stock, in the city in which the medical devices were located, had a positive impact on the performance of both internal and external governance structures. Online service also had a positive impact on both, with a stronger positive impact on the performance of internal governance than on that of external governance. For transactions governed by external structures, better performance was seen in private hospitals than in public ones. In public health institutions, internal governance showed better performance than external governance. Both internal and external governance structures showed better performance in private healthcare institutions than in public ones. In public health institutions, internal governance shows better performance than external governance; this suggests that healthcare managers should reconsider the trend to eliminate in-house maintenance service staff in public healthcare institutions.

Nanoscale inhomogeneity and photoacid generation dynamics in extreme ultraviolet resist materials

NASA Astrophysics Data System (ADS)

Wu, Ping-Jui; Wang, Yu-Fu; Chen, Wei-Chi; Wang, Chien-Wei; Cheng, Joy; Chang, Vencent; Chang, Ching-Yu; Lin, John; Cheng, Yuan-Chung

2018-03-01

The development of extreme ultraviolet (EUV) lithography towards the 22 nm node and beyond depends critically on the availability of resist materials that meet stringent control requirements in resolution, line edge roughness, and sensitivity. However, the molecular mechanisms that govern the structure-function relationships in current EUV resist systems are not well understood. In particular, the nanoscale structures of the polymer base and the distributions of photoacid generators (PAGs) should play a critical roles in the performance of a resist system, yet currently available models for photochemical reactions in EUV resist systems are exclusively based on homogeneous bulk models that ignore molecular-level details of solid resist films. In this work, we investigate how microscopic molecular organizations in EUV resist affect photoacid generations in a bottom-up approach that describes structure-dependent electron-transfer dynamics in a solid film model. To this end, molecular dynamics simulations and stimulated annealing are used to obtain structures of a large simulation box containing poly(4-hydroxystyrene) (PHS) base polymers and triphenylsulfonium based PAGs. Our calculations reveal that ion-pair interactions govern the microscopic distributions of the polymer base and PAG molecules, resulting in a highly inhomogeneous system with nonuniform nanoscale chemical domains. Furthermore, the theoretical structures were used in combination of quantum chemical calculations and the Marcus theory to evaluate electron transfer rates between molecular sites, and then kinetic Monte Carlo simulations were carried out to model electron transfer dynamics with molecular structure details taken into consideration. As a result, the portion of thermalized electrons that are absorbed by the PAGs and the nanoscale spatial distribution of generated acids can be estimated. Our data reveal that the nanoscale inhomogeneous distributions of base polymers and PAGs strongly affect the electron transfer and the performance of the resist system. The implications to the performances of EUV resists and key engineering requirements for improved resist systems will also be discussed in this work. Our results shed light on the fundamental structure dependence of photoacid generation and the control of the nanoscale structures as well as base polymer-PAG interactions in EVU resist systems, and we expect these knowledge will be useful for the future development of improved EUV resist systems.

45 CFR 155.110 - Entities eligible to carry out Exchange functions.

Code of Federal Regulations, 2014 CFR

2014-10-01

... governance structure. (e) SHOP independent governance. (1) A State may elect to create an independent governance and administrative structure for the SHOP, consistent with this section, if the State ensures that the SHOP coordinates and shares relevant information with the Exchange operating in the same service...

45 CFR 155.110 - Entities eligible to carry out Exchange functions.

Code of Federal Regulations, 2013 CFR

2013-10-01

... governance structure. (e) SHOP independent governance. (1) A State may elect to create an independent governance and administrative structure for the SHOP, consistent with this section, if the State ensures that the SHOP coordinates and shares relevant information with the Exchange operating in the same service...

45 CFR 155.110 - Entities eligible to carry out Exchange functions.

Code of Federal Regulations, 2012 CFR

2012-10-01

... governance structure. (e) SHOP independent governance. (1) A State may elect to create an independent governance and administrative structure for the SHOP, consistent with this section, if the State ensures that the SHOP coordinates and shares relevant information with the Exchange operating in the same service...

Vaccinovigilance in Europe--need for timeliness, standardization and resources.

PubMed Central

Lankinen, Kari S.; Pastila, Satu; Kilpi, Terhi; Nohynek, Hanna; Mäkelä, P. Helena; Olin, Patrick

2004-01-01

OBJECTIVE: To identify gaps in the systems for reporting adverse events following immunization (AEFI) in Europe by means of an interactive database constructed using a standardized approach. METHODS: A comparative survey was conducted in 1999-2000, using structured questionnaires addressed to the government authorities responsible for national immunization programmes and drug safety surveillance in all European Union (EU) Member States and in Norway and Switzerland. FINDINGS: The reporting of adverse vaccine reactions (AVRs) is covered by regulations in 13 of the 17 countries. Four countries have a specialized expert group with responsibility for vaccine safety. Only six professionals work full-time on vaccine safety in the 17 countries; in four of these countries the person is medically qualified. Fourteen countries have centralized reporting systems; in 14 countries the responsible authority is the drug regulatory agency. AEFI are reported using the procedure used for adverse drug reactions (ADRs) in all except four countries. The reporting form is not usually designed for vaccines and important details may therefore not be requested. Clinical definitions for vaccine reactions are not available. Twelve countries have appropriate official definitions for events or reactions, but the list of reportable events varies considerably between countries. The assessment of adverse vaccine reactions (AVRs) is hampered by lack of exact denominator data. Feedback to the rapporteurs was provided in 13 countries, but its quality was highly variable. CONCLUSION: The database facilitated a simple comparison of vaccinovigilance systems across participating countries. Most of the problems identified related to the reporting and analysis of AEFI could be solved through standardization and intensified international collaboration. On a national level, functional vaccinovigilance systems should be the shared responsibility of the drug regulatory authority and the national immunization programme. The resources for development and management of vaccine safety systems should be urgently improved. PMID:15640918

Reactions driving conformational movements (molecular motors) in gels: conformational and structural chemical kinetics.

PubMed

Otero, Toribio F

2017-01-18

In this perspective the empirical kinetics of conducting polymers exchanging anions and solvent during electrochemical reactions to get dense reactive gels is reviewed. The reaction drives conformational movements of the chains (molecular motors), exchange of ions and solvent with the electrolyte and structural (relaxation, swelling, shrinking and compaction) gel changes. Reaction-driven structural changes are identified and quantified from electrochemical responses. The empirical reaction activation energy (E a ), the reaction coefficient (k) and the reaction orders (α and β) change as a function of the conformational energy variation during the reaction. This conformational energy becomes an empirical magnitude. E a , k, α and β include and provide quantitative conformational and structural information. The chemical kinetics becomes structural chemical kinetics (SCK) for reactions driving conformational movements of the reactants. The electrochemically stimulated conformational relaxation model describes empirical results and some results from the literature for biochemical reactions. In parallel the development of an emerging technological world of soft, wet, multifunctional and biomimetic tools and anthropomorphic robots driven by reactions of the constitutive material, as in biological organs, can be now envisaged being theoretically supported by the kinetic model.

Engagement, empowerment, and job satisfaction before implementing an academic model of shared governance.

PubMed

Owen, D C; Boswell, C; Opton, L; Franco, L; Meriwether, C

2018-06-01

Baseline information was obtained from a School of Nursing faculty and staff about perceptions of job satisfaction, empowerment, and engagement in the workplace before the introduction of an integrated faculty and staff shared governance system. Governance structure in schools of nursing has the potential to enhance or impose constraints on the work environment for faculty, staff, and stakeholders. RESULTS: Faculty and staff perceptions of job satisfaction and engagement in the workplace before the introduction of a new model of shared governance are presented. Statistical differences were found between faculty and staff responses on the overall or total scales and select subscales, and group patterns of relationships differed. We provided a description of the first shared governance structure derived from the perspective of shared governance as defined and operationalized in Magnet Hospital health care systems and includes administrators, faculty, and staff in decision-making councils. As academia embarks on this change in governance structure from hierarchical to a more flattened approach findings support examining levels of work engagement, structural and psychological empowerment, and job satisfaction as key monitors of the work environment. Copyright © 2018 Elsevier Inc. All rights reserved.

Energy Education in Brazil.

ERIC Educational Resources Information Center

Messick, Rosemary; de Paiva, Terezhina Villela O'Grady

1980-01-01

Compares energy education in Brazil and the United States. Topics discussed include the Brazilian setting, government initiatives, dependence on foreign fuel sources, public reaction, schools and energy education, and mass media involvement. (DB)

42 CFR 416.47 - Condition for coverage-Medical records.

Code of Federal Regulations, 2013 CFR

2013-10-01

...) Patient identification. (2) Significant medical history and results of physical examination. (3) Pre... the governing body. (5) Any allergies and abnormal drug reactions. (6) Entries related to anesthesia...

42 CFR 416.47 - Condition for coverage-Medical records.

Code of Federal Regulations, 2012 CFR

2012-10-01

...) Patient identification. (2) Significant medical history and results of physical examination. (3) Pre... the governing body. (5) Any allergies and abnormal drug reactions. (6) Entries related to anesthesia...

42 CFR 416.47 - Condition for coverage-Medical records.

Code of Federal Regulations, 2014 CFR

2014-10-01

...) Patient identification. (2) Significant medical history and results of physical examination. (3) Pre... the governing body. (5) Any allergies and abnormal drug reactions. (6) Entries related to anesthesia...

42 CFR 416.47 - Condition for coverage-Medical records.

Code of Federal Regulations, 2011 CFR

2011-10-01

...) Patient identification. (2) Significant medical history and results of physical examination. (3) Pre... the governing body. (5) Any allergies and abnormal drug reactions. (6) Entries related to anesthesia...

42 CFR 416.47 - Condition for coverage-Medical records.

Code of Federal Regulations, 2010 CFR

2010-10-01

...) Patient identification. (2) Significant medical history and results of physical examination. (3) Pre... the governing body. (5) Any allergies and abnormal drug reactions. (6) Entries related to anesthesia...

28 CFR 31.102 - State agency structure.

Code of Federal Regulations, 2014 CFR

2014-07-01

... Applicants § 31.102 State agency structure. The State agency may be a discrete unit of State government or a... 28 Judicial Administration 1 2014-07-01 2014-07-01 false State agency structure. 31.102 Section 31... unit of State government. Details of organization and structure are matters of State discretion...

28 CFR 31.102 - State agency structure.

Code of Federal Regulations, 2013 CFR

2013-07-01

... Applicants § 31.102 State agency structure. The State agency may be a discrete unit of State government or a... 28 Judicial Administration 1 2013-07-01 2013-07-01 false State agency structure. 31.102 Section 31... unit of State government. Details of organization and structure are matters of State discretion...

28 CFR 31.102 - State agency structure.

Code of Federal Regulations, 2012 CFR

2012-07-01

... Applicants § 31.102 State agency structure. The State agency may be a discrete unit of State government or a... 28 Judicial Administration 1 2012-07-01 2012-07-01 false State agency structure. 31.102 Section 31... unit of State government. Details of organization and structure are matters of State discretion...

28 CFR 31.102 - State agency structure.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Applicants § 31.102 State agency structure. The State agency may be a discrete unit of State government or a... 28 Judicial Administration 1 2011-07-01 2011-07-01 false State agency structure. 31.102 Section 31... unit of State government. Details of organization and structure are matters of State discretion...

28 CFR 31.102 - State agency structure.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Applicants § 31.102 State agency structure. The State agency may be a discrete unit of State government or a... 28 Judicial Administration 1 2010-07-01 2010-07-01 false State agency structure. 31.102 Section 31... unit of State government. Details of organization and structure are matters of State discretion...

Unexpected peaks in tandem mass spectra due to reaction of product ions with residual water in mass spectrometer collision cells.

PubMed

Neta, Pedatsur; Farahani, Mahnaz; Simón-Manso, Yamil; Liang, Yuxue; Yang, Xiaoyu; Stein, Stephen E

2014-12-15

Certain product ions in electrospray ionization tandem mass spectrometry are found to react with residual water in the collision cell. This reaction often leads to the formation of ions that cannot be formed directly from the precursor ions, and this complicates the mass spectra and may distort MRM (multiple reaction monitoring) results. Various drugs, pesticides, metabolites, and other compounds were dissolved in acetonitrile/water/formic acid and studied by electrospray ionization mass spectrometry to record their MS(2) and MS(n) spectra in several mass spectrometers (QqQ, QTOF, IT, and Orbitrap HCD). Certain product ions were found to react with residual water in collision cells. The reaction was confirmed by MS(n) studies and the rate of reaction was determined in the IT instrument using zero collision energy and variable activation times. Examples of product ions reacting with water include phenyl and certain substituted phenyl cations, benzoyl-type cations formed from protonated folic acid and similar compounds by loss of the glutamate moiety, product ions formed from protonated cyclic siloxanes by loss of methane, product ions formed from organic phosphates, and certain negative ions. The reactions of product ions with residual water varied greatly in their rate constant and in the extent of reaction (due to isomerization). Various types of product ions react with residual water in mass spectrometer collision cells. As a result, tandem mass spectra may contain unexplained peaks and MRM results may be distorted by the occurrence of such reactions. These often unavoidable reactions must be taken into account when annotating peaks in tandem mass spectra and when interpreting MRM results. Published in 2014. This article is a U.S. Government work and is in the public domain in the USA. Published in 2014. This article is a U.S. Government work and is in the public domain in the USA.

How alkyl halide structure affects E2 and SN2 reaction barriers: E2 reactions are as sensitive as SN2 reactions.

PubMed

Rablen, Paul R; McLarney, Brett D; Karlow, Brandon J; Schneider, Jean E

2014-02-07

High-level electronic structure calculations, including a continuum treatment of solvent, are employed to elucidate and quantify the effects of alkyl halide structure on the barriers of SN2 and E2 reactions. In cases where such comparisons are available, the results of these calculations show close agreement with solution experimental data. Structural factors investigated include α- and β-methylation, adjacency to unsaturated functionality (allyl, benzyl, propargyl, α to carbonyl), ring size, and α-halogenation and cyanation. While the influence of these factors on SN2 reactivity is mostly well-known, the present study attempts to provide a broad comparison of both SN2 and E2 reactivity across many cases using a single methodology, so as to quantify relative reactivity trends. Despite the fact that most organic chemistry textbooks say far more about how structure affects SN2 reactions than about how it affects E2 reactions, the latter are just as sensitive to structural variation as are the former. This sensitivity of E2 reactions to structure is often underappreciated.

Structured vs. Unstructured: Factors Affecting Adverse Drug Reaction Documentation in an EMR Repository

PubMed Central

Skentzos, Stephen; Shubina, Maria; Plutzky, Jorge; Turchin, Alexander

2011-01-01

Adverse reactions to medications to which the patient was known to be intolerant are common. Electronic decision support can prevent them but only if history of adverse reactions to medications is recorded in structured format. We have conducted a retrospective study of 31,531 patients with adverse reactions to statins documented in the notes, as identified with natural language processing. The software identified statin adverse reactions with sensitivity of 86.5% and precision of 91.9%. Only 9020 of these patients had an adverse reaction to a statin recorded in structured format. In multivariable analysis the strongest predictor of structured documentation was utilization of EMR functionality that integrated the medication list with the structured medication adverse reaction repository (odds ratio 48.6, p < 0.0001). Integration of information flow between EMR modules can help improve documentation and potentially prevent adverse drug events. PMID:22195188

Collective Bargaining in Catholic Schools: What Does Governance Have to Do with It?

ERIC Educational Resources Information Center

James, John T.

2004-01-01

This article outlines the significant legal decisions regarding collective bargaining in Catholic schools, identifies the governance structures employed in Catholic schools and the methods of translating these governance structures into documents required by civil law, and concludes with the citation of two recent court decisions that demonstrate…

75 FR 3223 - California Independent System Operator Corporation; Midwest Independent Transmission System...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-01-20

... the RTO/ISO stakeholder process and governance structure. First, NASUCA states that it is necessary to...' Council filed a motion to lodge a report on RTO/ISO governance written by the National Association of... wherever possible. Next, NASUCA proposes a revised governance structure that reflects consumer interests at...

How to Evaluate a Faculty Governance Structure

ERIC Educational Resources Information Center

Cordes, John W.; Dunbar, David; Gingerich, Jeff

2013-01-01

During the 2010-11 academic year, Cabrini College began an evaluation of a faculty governance structure that had been implemented in fall 2007. The processes involved might serve as a roadmap for faculty members and administrators at other institutions who seek to understand the strengths and weaknesses of their governance model and improve shared…

Alkyne Benzannulation Reactions for the Synthesis of Novel Aromatic Architectures.

PubMed

Hein, Samuel J; Lehnherr, Dan; Arslan, Hasan; J Uribe-Romo, Fernando; Dichtel, William R

2017-11-21

Aromatic compounds and polymers are integrated into organic field effect transistors, light-emitting diodes, photovoltaic devices, and redox-flow batteries. These compounds and materials feature increasingly complex designs, and substituents influence energy levels, bandgaps, solution conformation, and crystal packing, all of which impact performance. However, many polycyclic aromatic hydrocarbons of interest are difficult to prepare because their substitution patterns lie outside the scope of current synthetic methods, as strategies for functionalizing benzene are often unselective when applied to naphthalene or larger systems. For example, cross-coupling and nucleophilic aromatic substitution reactions rely on prefunctionalized arenes, and even directed metalation methods most often modify positions near Lewis basic sites. Similarly, electrophilic aromatic substitutions access single regioisomers under substrate control. Cycloadditions provide a convergent route to densely functionalized aromatic compounds that compliment the above methods. After surveying cycloaddition reactions that might be used to modify the conjugated backbone of poly(phenylene ethynylene)s, we discovered that the Asao-Yamamoto benzannulation reaction is notably efficient. Although this reaction had been reported a decade earlier, its scope and usefulness for synthesizing complex aromatic systems had been under-recognized. This benzannulation reaction combines substituted 2-(phenylethynyl)benzaldehydes and substituted alkynes to form 2,3-substituted naphthalenes. The reaction tolerates a variety of sterically congested alkynes, making it well-suited for accessing poly- and oligo(ortho-arylene)s and contorted hexabenzocoronenes. In many cases in which asymmetric benzaldehyde and alkyne cycloaddition partners are used, the reaction is regiospecific based on the electronic character of the alkyne substrate. Recognizing these desirable features, we broadened the substrate scope to include silyl- and halogen-substituted alkynes. Through a combined experimental and computational approach, we have elucidated mechanistic insight and key principles that govern the regioselectivity outcome of the benzannulation of structurally diverse alkynes. We have applied these methods to prepare sterically hindered, shape-persistent aromatic systems, heterocyclic aromatic compounds, functionalized 2-aryne precursors, polyheterohalogenated naphthalenes, ortho-arylene foldamers, and graphene nanoribbons. As a result of these new synthetic avenues, aromatic structures with interesting properties were uncovered such as ambipolar charge transport in field effect transistors based on our graphene nanoribbons, conformational aspects of ortho-arylene architectures resulting from intramolecular π-stacking, and modulation of frontier molecular orbitals via protonation of heteroatom containing aromatic systems. Given the availability of many substituted 2-(phenylethynyl)benzaldehydes and the regioselectivity of the benzannulation reaction, naphthalenes can be prepared with control of the substitution pattern at seven of the eight substitutable positions. Researchers in a range of fields are likely to benefit directly from newly accessible molecular and polymeric systems derived from polyfunctionalized naphthalenes.

From "Boy-Government" and "Student-Government" to "Learner-Government": The Best of Both Worlds?

ERIC Educational Resources Information Center

Mathebula, Thokozani

2018-01-01

In the history of South African education there have been three contrasting attempts to incorporate learners into the authority structures of schools, namely: "boy-government" (prefect system), "student-government" (Student Representative Councils (SRCs)) and "learner-government" (Representative Councils of Learners…

Universality and chaoticity in ultracold K+KRb chemical reactions

DOE PAGES

Croft, J. F. E.; Makrides, C.; Li, M.; ...

2017-07-19

A fundamental question in the study of chemical reactions is how reactions proceed at a collision energy close to absolute zero. This question is no longer hypothetical: quantum degenerate gases of atoms and molecules can now be created at temperatures lower than a few tens of nanokelvin. Here we consider the benchmark ultracold reaction between, the most-celebrated ultracold molecule, KRb and K. We map out an accurate ab initio ground-state potential energy surface of the K 2Rb complex in full dimensionality and report numerically-exact quantum-mechanical reaction dynamics. The distribution of rotationally resolved rates is shown to be Poissonian. An analysismore » of the hyperspherical adiabatic potential curves explains this statistical character revealing a chaotic distribution for the short-range collision complex that plays a key role in governing the reaction outcome.« less

School Choice for the Poor? The Limits of Marketisation of Primary Education in Rural India. CREATE Pathways to Access. Research Monograph No. 23

ERIC Educational Resources Information Center

Harma, Joanna

2010-01-01

In recent years India has seen an explosion in low-fee private (LFP) schooling aimed at the poorer strata of society. This marketisation of primary education is a reaction to the well-documented failings of the government system. This paper looks at LFP schooling in one rural district of Uttar Pradesh, and compares government to low cost private…

Time to dismiss the idea of a structural fix within government? An analysis of intersectoral action for health in Danish municipalities.

PubMed

Holt, Ditte H; Carey, Gemma; Rod, Morten H

2018-06-01

This paper examines the role of organizational structure within government(s) in attempts to implement intersectoral action for health in Danish municipalities. We discuss the implications of structural reorganization and the governance structures that are established in order to ensure coordination and integration between policy sectors. The paper is based on 49 interviews with civil servants from health and non-health sectors of 10 municipalities. Based on participants' experiences, cases have been described and analyzed in an iterative process consulting the literature on Health in All Policies and joined-up government. Continuous and frequent processes of reorganizing were widespread in the municipalities. However, they appeared to have little effect on policy change. The two most common governance structures established to transcend organizational boundaries were the central unit and the intersectoral committee. According to the experiences of participants, paradoxically both of these organizational solutions tend to reproduce the organizational problems they are intended to overcome. Even if structural reorganization may succeed in dissolving some sector boundaries, it will inevitably create new ones. It is time to dismiss the idea that intersectoral action for health can be achieved by means of a structural fix. Rather than rearranging organizational boundaries it may be more useful to seek to manage the silos which exist in any organization, e.g. by promoting awareness of their implications for public health action and by enhancing the boundary spanning skills of public health officers.

REACTOR

DOEpatents

Christy, R.F.

1961-07-25

A means is described for co-relating the essential physical requirements of a fission chain reaction in order that practical, compact, and easily controllable reactors can be built. These objects are obtained by employing a composition of fissionsble isotope and moderator in fluid form in which the amount of fissionsble isotcpe present governs the reaction. The size of the reactor is no longer a critical factor, the new criterion being the concentration of the fissionable isotope.

Robotic reactions: delay-induced patterns in autonomous vehicle systems.

PubMed

Orosz, Gábor; Moehlis, Jeff; Bullo, Francesco

2010-02-01

Fundamental design principles are presented for vehicle systems governed by autonomous cruise control devices. By analyzing the corresponding delay differential equations, it is shown that for any car-following model short-wavelength oscillations can appear due to robotic reaction times, and that there are tradeoffs between the time delay and the control gains. The analytical findings are demonstrated on an optimal velocity model using numerical continuation and numerical simulation.

Robotic reactions: Delay-induced patterns in autonomous vehicle systems

NASA Astrophysics Data System (ADS)

Orosz, Gábor; Moehlis, Jeff; Bullo, Francesco

2010-02-01

Fundamental design principles are presented for vehicle systems governed by autonomous cruise control devices. By analyzing the corresponding delay differential equations, it is shown that for any car-following model short-wavelength oscillations can appear due to robotic reaction times, and that there are tradeoffs between the time delay and the control gains. The analytical findings are demonstrated on an optimal velocity model using numerical continuation and numerical simulation.

Comparison of DSMC Reaction Models with QCT Reaction Rates for Nitrogen

DTIC Science & Technology

2016-07-17

The U.S. Government is joint author of the work and has the right to use, modify, reproduce, release, perform, display, or disclose the work. 13...Distribution A: Approved for Public Release, Distribution Unlimited PA #16299 Introduction • Comparison with measurements is final goal • Validation...model verification and parameter adjustment • Four chemistry models: total collision energy (TCE), quantum kinetic (QK), vibration-dissociation favoring

Governance versus government: drug consumption rooms in Australia and the UK.

PubMed

Zampini, Giulia Federica

2014-09-01

To evaluate, through a case study, the extent to which elements of governance and elements of government are influential in determining the implementation or non-implementation of a drugs intervention. Comparative analysis of the case of a drug consumption room in the UK (England) and Australia (New South Wales), including 16 semi-structured interviews with key stakeholders and analysis of relevant documents according to characteristic features of governance and government (power decentralisation, power centralisation, independent self-organising policy networks, use of evidence, top-down steering/directing, legislation). Characteristic features of both governance and government are found in the data. Elements of governance are more prominent in New South Wales, Australia than in England, UK, where government prevails. Government is seen as the most important actor at play in the making, or absence, of drug consumption rooms. Both governance and government are useful frameworks in conceptualising the policy process. The governance narrative risks overlooking the importance of traditional government structures. In the case of drug consumption rooms in the UK and Australia, a focus on government is shown to have been crucial in determining whether the intervention was implemented. Copyright © 2014 Elsevier B.V. All rights reserved.

State Governance Action Report, 2007

ERIC Educational Resources Information Center

Association of Governing Boards of Universities and Colleges, 2007

2007-01-01

This paper presents the State Governance Action Report for 2007. Compiled in this report are state policy developments, including legislation, commissions, and studies, affecting the structure, responsibilities, and operations of public higher education governing boards and institutionally related foundations. Governance and governance-related…

Complex Chemical Reaction Networks from Heuristics-Aided Quantum Chemistry.

PubMed

Rappoport, Dmitrij; Galvin, Cooper J; Zubarev, Dmitry Yu; Aspuru-Guzik, Alán

2014-03-11

While structures and reactivities of many small molecules can be computed efficiently and accurately using quantum chemical methods, heuristic approaches remain essential for modeling complex structures and large-scale chemical systems. Here, we present a heuristics-aided quantum chemical methodology applicable to complex chemical reaction networks such as those arising in cell metabolism and prebiotic chemistry. Chemical heuristics offer an expedient way of traversing high-dimensional reactive potential energy surfaces and are combined here with quantum chemical structure optimizations, which yield the structures and energies of the reaction intermediates and products. Application of heuristics-aided quantum chemical methodology to the formose reaction reproduces the experimentally observed reaction products, major reaction pathways, and autocatalytic cycles.

System-Level Shared Governance Structures and Processes in Healthcare Systems With Magnet®-Designated Hospitals: A Descriptive Study.

PubMed

Underwood, Carlisa M; Hayne, Arlene N

The purpose was to identify and describe structures and processes of best practices for system-level shared governance in healthcare systems. Currently, more than 64.6% of US community hospitals are part of a system. System chief nurse executives (SCNEs) are challenged to establish leadership structures and processes that effectively and efficiently disseminate best practices for patients and staff across complex organizations, geographically dispersed locations, and populations. Eleven US healthcare SCNEs from the American Nurses Credentialing Center's repository of Magnet®-designated facilities participated in a 35-multiquestion interview based on Kanter's Theory of Organizational Empowerment. Most SCNEs reported the presence of more than 50% of the empowerment structures and processes in system-level shared governance. Despite the difficulties and complexities of growing health systems, SCNEs have replicated empowerment characteristics of hospital shared governance structures and processes at the system level.

Advancing Theory on Knowledge Governance in Universities: A Case Study of a Higher Education Merger

ERIC Educational Resources Information Center

Safavi, Mehdi; Håkanson, Lars

2018-01-01

The deep structure of university knowledge governance system is uncharted. In an exploratory case study of a university merger with an art college, this study inductively examines how knowledge governance structures in universities affect (and are affected by) the creation and passing on of knowledge. The authors found the university governance…

Information Technology (IT) Strategic Alignment: A Correlational Study between the Impact of IT Governance Structures and IT Strategic Alignment

ERIC Educational Resources Information Center

Asante, Keith K.

2010-01-01

This dissertation explored the extent to which Information Technology (IT) strategic alignment are impacted by IT governance structures. The study discusses several strategic alignment and IT governance literature that presents a gap in the literature domain. Subsequent studies researched issues surrounding why organizations are not able to align…

Measuring Institutional Effectiveness of California Community Colleges through Existing Governance Structures and External Funding Efforts

ERIC Educational Resources Information Center

Jameson-Meledy, Kathryn

2013-01-01

The purpose of this research was to compare the differing structures of governance within the California Community College (CCC) system in relation to resource development and grant management. This is to explain how governance may impact the effectiveness of institutions to strengthen services to students with funding resources secured through…

Energy Transformations of Soil Organic Matter in a Changing World

NASA Astrophysics Data System (ADS)

Herrmann, A. M.; Coucheney, E.; Grice, S. M.; Ritz, K.; Harris, J.

2011-12-01

The role of soils in governing the terrestrial carbon balance is acknowledged as being important but remains poorly understood within the context of climate change. Soils exchange energy with their surroundings and are therefore open systems thermodynamically, but little is known how energy transformations of decomposition processes are affected by temperature. Soil organic matter and the soil biomass can be conceptualised as analogous to the 'fuel' and 'biological engine' of the earth, respectively, and are pivotal in driving the belowground carbon cycle. Thermodynamic principles of soil organic matter decomposition were evaluated by means of isothermal microcalorimetry (TAM Air, TA Instruments, Sollentuna Sweden: (i) Mineral forest soils from the Flakaliden long-term nitrogen fertilisation experiment (Sweden) were amended with a range of different substrates representing structurally simple to complex, ecologically pertinent organic matter and heat signatures were determined at temperatures between 5 and 25°C. (ii) Thermodynamic and resource-use efficiencies of the biomass were determined in arable soils which received contrasting long-term management regimes with respect to organic matter and nitrogen since 1956. The work showed that (i) structurally labile components have higher activation energy and temperature dependence than structurally more complex organic components. This is, however, in contrast to the thermodynamic argument which suggests the opposite that reactions metabolising structurally complex, aromatic components have higher temperature dependence than reactions metabolising structurally more labile components. (ii) Microbial communities exposed to long-term stress by heavy metal and low pH were less thermodynamic efficient and showed a decrease in resource-use efficiency in comparison with conventional input regimes. Differences in efficiencies were mirrored in both the phenotypic and functional profiles of the communities. We will present our findings illustrating the capacity of isothermal microcalorimetry to evaluate temperature dependencies of soil organic matter decomposition, associated energy transformations and thermodynamic principles in soil ecosystems.

Osmotic propulsion: the osmotic motor.

PubMed

Córdova-Figueroa, Ubaldo M; Brady, John F

2008-04-18

A model for self-propulsion of a colloidal particle--the osmotic motor--immersed in a dispersion of "bath" particles is presented. The nonequilibrium concentration of bath particles induced by a surface chemical reaction creates an osmotic pressure imbalance on the motor causing it to move. The ratio of the speed of reaction to that of diffusion governs the bath particle distribution which is employed to calculate the driving force on the motor, and from which the self-induced osmotic velocity is determined. For slow reactions, the self-propulsion is proportional to the reaction velocity. When surface reaction dominates over diffusion the osmotic velocity cannot exceed the diffusive speed of the bath particles. Implications of these features for different bath particle volume fractions and motor sizes are discussed. Theoretical predictions are compared with Brownian dynamics simulations.

Osmotic Propulsion: The Osmotic Motor

NASA Astrophysics Data System (ADS)

Córdova-Figueroa, Ubaldo M.; Brady, John F.

2008-04-01

A model for self-propulsion of a colloidal particle—the osmotic motor—immersed in a dispersion of “bath” particles is presented. The nonequilibrium concentration of bath particles induced by a surface chemical reaction creates an osmotic pressure imbalance on the motor causing it to move. The ratio of the speed of reaction to that of diffusion governs the bath particle distribution which is employed to calculate the driving force on the motor, and from which the self-induced osmotic velocity is determined. For slow reactions, the self-propulsion is proportional to the reaction velocity. When surface reaction dominates over diffusion the osmotic velocity cannot exceed the diffusive speed of the bath particles. Implications of these features for different bath particle volume fractions and motor sizes are discussed. Theoretical predictions are compared with Brownian dynamics simulations.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Croft, J. F. E.; Makrides, C.; Li, M.

A fundamental question in the study of chemical reactions is how reactions proceed at a collision energy close to absolute zero. This question is no longer hypothetical: quantum degenerate gases of atoms and molecules can now be created at temperatures lower than a few tens of nanokelvin. Here we consider the benchmark ultracold reaction between, the most-celebrated ultracold molecule, KRb and K. We map out an accurate ab initio ground-state potential energy surface of the K 2Rb complex in full dimensionality and report numerically-exact quantum-mechanical reaction dynamics. The distribution of rotationally resolved rates is shown to be Poissonian. An analysismore » of the hyperspherical adiabatic potential curves explains this statistical character revealing a chaotic distribution for the short-range collision complex that plays a key role in governing the reaction outcome.« less

Numerical study of supersonic combustion using a finite rate chemistry model

NASA Technical Reports Server (NTRS)

Chitsomboon, T.; Tiwari, S. N.; Kumar, A.; Drummond, J. P.

1986-01-01

The governing equations of two-dimensional chemically reacting flows are presented together with a global two-step chemistry model for H2-air combustion. The explicit unsplit MacCormack finite difference algorithm is used to advance the discrete system of the governing equations in time until convergence is attained. The source terms in the species equations are evaluated implicitly to alleviate stiffness associated with fast reactions. With implicit source terms, the species equations give rise to a block-diagonal system which can be solved very efficiently on vector-processing computers. A supersonic reacting flow in an inlet-combustor configuration is calculated for the case where H2 is injected into the flow from the side walls and the strut. Results of the calculation are compared against the results obtained by using a complete reaction model.

Semi-analytical solutions of the Schnakenberg model of a reaction-diffusion cell with feedback

NASA Astrophysics Data System (ADS)

Al Noufaey, K. S.

2018-06-01

This paper considers the application of a semi-analytical method to the Schnakenberg model of a reaction-diffusion cell. The semi-analytical method is based on the Galerkin method which approximates the original governing partial differential equations as a system of ordinary differential equations. Steady-state curves, bifurcation diagrams and the region of parameter space in which Hopf bifurcations occur are presented for semi-analytical solutions and the numerical solution. The effect of feedback control, via altering various concentrations in the boundary reservoirs in response to concentrations in the cell centre, is examined. It is shown that increasing the magnitude of feedback leads to destabilization of the system, whereas decreasing this parameter to negative values of large magnitude stabilizes the system. The semi-analytical solutions agree well with numerical solutions of the governing equations.

Building a Governance Strategy for CER: The Patient Outcomes Research to Advance Learning (PORTAL) Network Experience

PubMed Central

Paolino, Andrea R.; McGlynn, Elizabeth A.; Lieu, Tracy; Nelson, Andrew F.; Prausnitz, Stephanie; Horberg, Michael A.; Arterburn, David E.; Gould, Michael K.; Laws, Reesa L.; Steiner, John F.

2016-01-01

Introduction: The Patient Outcomes Research to Advance Learning (PORTAL) Network was established with funding from the Patient-Centered Outcomes Research Institute (PCORI) in 2014. The PORTAL team adapted governance structures and processes from past research network collaborations. We will review and outline the structures and processes of the PORTAL governance approach and describe how proactively focusing on priority areas helped us to facilitate an ambitious research agenda. Background: For years a variety of funders have supported large-scale infrastructure grants to promote the use of clinical datasets to answer important comparative effectiveness research (CER) questions. These awards have provided the impetus for health care systems to join forces in creating clinical data research networks. Often, these scientific networks do not develop governance processes proactively or systematically, and address issues only as problems arise. Even if network leaders and collaborators foresee the need to develop governance approaches, they may underestimate the time and effort required to develop sound processes. The resulting delays can impede research progress. Innovation: Because the PORTAL sites had built trust and a foundation of collaboration by participating with one another in past research networks, essential elements of effective governance such as guiding principles, decision making processes, project governance, data governance, and stakeholders in governance were familiar to PORTAL investigators. This trust and familiarity enabled the network to rapidly prioritize areas that required sound governance approaches: responding to new research opportunities, creating a culture of trust and collaboration, conducting individual studies, within the broader network, assigning responsibility and credit to scientific investigators, sharing data while protecting privacy/security, and allocating resources. The PORTAL Governance Document, complete with a Toolkit of Appendices is included for reference and for adaptation by other networks. Credibility: As a result of identifying project-based governance priorities (IRB approval, subcontracting, selection of new research including lead PI and participating sites, and authorship) and data governance priorities (reciprocal data use agreement, analytic plan procedures, and other tools for data governance), PORTAL established most of its governance structure by Month 6 of the 18 month project. This allowed science to progress and collaborators to experience first-hand how the structures and procedures functioned in the remaining 12 months of the project, leaving ample time to refine them and to develop new structures or processes as necessary. Discussion: The use of procedures and processes with which participating investigators and their home institutions were already familiar allowed project and regulatory requirements to be established quickly to protect patients, their data, and the health care systems that act as stewards for both. As the project progressed, PORTAL was able to test and adjust the structures it put place, and to make substantive revisions by Month 17. As a result, priority processes have been predictable, transparent and effective. Conclusion/Next steps: Strong governance practices are a stewardship responsibility of research networks to justify the trust of patients, health plan members, health care delivery organizations, and other stakeholders. Well-planned governance can reduce the time necessary to initiate the scientific activities of a network, a particular concern when the time frame to complete research is short. Effective network and data governance structures protect patient and institutional data as well as the interests of investigators and their institutions, and assures that the network has built an environment to meet the goals of the research. PMID:27141524

Building a Governance Strategy for CER: The Patient Outcomes Research to Advance Learning (PORTAL) Network Experience.

PubMed

Paolino, Andrea R; McGlynn, Elizabeth A; Lieu, Tracy; Nelson, Andrew F; Prausnitz, Stephanie; Horberg, Michael A; Arterburn, David E; Gould, Michael K; Laws, Reesa L; Steiner, John F

2016-01-01

The Patient Outcomes Research to Advance Learning (PORTAL) Network was established with funding from the Patient-Centered Outcomes Research Institute (PCORI) in 2014. The PORTAL team adapted governance structures and processes from past research network collaborations. We will review and outline the structures and processes of the PORTAL governance approach and describe how proactively focusing on priority areas helped us to facilitate an ambitious research agenda. For years a variety of funders have supported large-scale infrastructure grants to promote the use of clinical datasets to answer important comparative effectiveness research (CER) questions. These awards have provided the impetus for health care systems to join forces in creating clinical data research networks. Often, these scientific networks do not develop governance processes proactively or systematically, and address issues only as problems arise. Even if network leaders and collaborators foresee the need to develop governance approaches, they may underestimate the time and effort required to develop sound processes. The resulting delays can impede research progress. Because the PORTAL sites had built trust and a foundation of collaboration by participating with one another in past research networks, essential elements of effective governance such as guiding principles, decision making processes, project governance, data governance, and stakeholders in governance were familiar to PORTAL investigators. This trust and familiarity enabled the network to rapidly prioritize areas that required sound governance approaches: responding to new research opportunities, creating a culture of trust and collaboration, conducting individual studies, within the broader network, assigning responsibility and credit to scientific investigators, sharing data while protecting privacy/security, and allocating resources. The PORTAL Governance Document, complete with a Toolkit of Appendices is included for reference and for adaptation by other networks. As a result of identifying project-based governance priorities (IRB approval, subcontracting, selection of new research including lead PI and participating sites, and authorship) and data governance priorities (reciprocal data use agreement, analytic plan procedures, and other tools for data governance), PORTAL established most of its governance structure by Month 6 of the 18 month project. This allowed science to progress and collaborators to experience first-hand how the structures and procedures functioned in the remaining 12 months of the project, leaving ample time to refine them and to develop new structures or processes as necessary. The use of procedures and processes with which participating investigators and their home institutions were already familiar allowed project and regulatory requirements to be established quickly to protect patients, their data, and the health care systems that act as stewards for both. As the project progressed, PORTAL was able to test and adjust the structures it put place, and to make substantive revisions by Month 17. As a result, priority processes have been predictable, transparent and effective. Strong governance practices are a stewardship responsibility of research networks to justify the trust of patients, health plan members, health care delivery organizations, and other stakeholders. Well-planned governance can reduce the time necessary to initiate the scientific activities of a network, a particular concern when the time frame to complete research is short. Effective network and data governance structures protect patient and institutional data as well as the interests of investigators and their institutions, and assures that the network has built an environment to meet the goals of the research.

Chemical Constraints Governing the Origin of Metabolism: The Thermodynamic Landscape of Carbon Group Transformations

NASA Technical Reports Server (NTRS)

Weber, Arthur L.; Fonda, Mark (Technical Monitor)

2001-01-01

The thermodynamics of organic chemistry under mild aqueous conditions was examined in order to begin to understand its influence on the structure and operation of metabolism and its antecedents. Free energies were estimated for four types reactions of biochemical importance carbon-carbon bond cleavage and synthesis, hydrogen transfer between carbon groups, dehydration of alcohol groups, and aldo-keto isomerization. The energies were calculated for mainly aliphatic groups composed of carbon, hydrogen, and oxygen. The energy values showed that (1) when carbon-carbon bond cleavage involves two different types of functional groups, transfer of the shared electron-pair to the more reduced carbon group is energetically favored over transfer to the more oxidized carbon group, and (2) the energy of carbon-carbon bond transformation is strongly dependent on the type of functional group that donates the shared electron-pair during cleavage, and the group that accepts the shared electron-pair during synthesis, and (3) the energetics of C-C bond transformation is determined primarily by the half-reaction energies of the couples: carbonyl/carboxylic acid, carboxylic acid/carbon dioxide, alcohol/carbonyl, and hydrocarbon/alcohol. The energy of hydrogen-transfer between carbon groups was found to depend on the functional group class of both the hydrogen-donor and hydrogen-acceptor. From these and other observations we concluded that the chemistry of the origin of metabolism (and to a lesser degree modem metabolism) is strongly constrained by the (1) limited disproportionation energy of organic substrates that can be dissipated in a few irreversible reactions, (2) the energy-dominance of few half-reaction couples in carbon-carbon bond transformation that establishes whether a chemical reaction is energetically irreversible, reversible or unfeasible, and (3) the dependence of the transformation-energy on the oxidation state of carbon groups (functional group type) which is contingent on prior reactions in the synthetic pathway.

Governing the Governors: A Case Study of College Governance in English Further Education

ERIC Educational Resources Information Center

Gleeson, Denis; Abbott, Ian; Hill, Ron

2011-01-01

This paper addresses the nature of governors in the governance of further education colleges in an English context. It explores the complex relationship between governors (people/agency), government (policy/structure) and governance (practice), in a college environment. While recent research has focused on the governance of schooling and higher…

Multicomponent, flow diazotization/Mizoroki-Heck coupling protocol: dispelling myths about working with diazonium salts.

PubMed

Nalivela, Kumara S; Tilley, Michael; McGuire, Michael A; Organ, Michael G

2014-05-26

A single pass flow diazotization/Mizoroki-Heck protocol has been developed for the production of cinnimoyl and styryl products. The factors that govern aryl diazonium salt stability have been examined in detail leading to the development of a MeOH/DMF co-solvent system in which the diazonium salts can be generated in the presence of all other reaction components and then coupled selectively to give the desired products. Finally the key role of the reaction quench for flow reactions has been demonstrated. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Toward an Ideal Senior High School Governance Structure.

ERIC Educational Resources Information Center

Treslan, D. L.

1979-01-01

This paper delineates six attributes of an ideal high school governance structure: respect, freedom, rationality, flexibility, equality, and involvement of staff and students in the decision-making process. (Author/SJL)

Linking Supply Chain Governance and Biosecurity in the Context of HPAI Control in Western Java: A Value Chain Perspective

PubMed Central

Indrawan, Dikky; Rich, Karl M.; van Horne, Peter; Daryanto, Arief; Hogeveen, Henk

2018-01-01

Despite extensive efforts to control the highly pathogenic avian influenza (HPAI), it remains endemic in Western Java, Indonesia. To understand the limited effectiveness of HPAI control measures, it is important to map the complex structure of the poultry sector. The governance of the poultry value chain in particular, could play a pivotal role, yet there is limited information on the different chain governance structures and their impacts on HPAI control. This article uses value chain analysis (VCA), focusing on an in-depth assessment of governance structures as well as transaction cost economics and quantitative estimates of the market power of different chain actors, to establish a theoretical framework to examine biosecurity and HPAI control in the Western Java poultry chain. During the research, semi-structured interviews were conducted with key value-chain stakeholders, and the economic performance of identified actors was estimated. Results indicated the co-existence of four different poultry value chains in West Java: the integrator chain, the semi-automated slaughterhouse chain, the controlled slaughter-point chain, and the private slaughter-point chain. The integrator chain was characterized by the highest levels of coordination and a tight, hierarchical governance. In contrast, the other three types of value chains were less coordinated. The market power of the different actors within the four value chains also differed. In more integrated chains, slaughterhouses held considerable market power, while in more informal value chains, market power was in the hands of traders. The economic effects of HPAI and biosecurity measures also varied for the identified actors in the different value chains. Implementation of biosecurity and HPAI control measures was strongly related to the governance structure of the chain, with interactions between different chains and governance structures accentuating the risk of HPAI. Our findings highlight that a proper understanding of the chain governance structure is vital to improve the effectiveness of HPAI control measures, by making the interventions more specific and fit-for-purpose given the incentive structures present in different chains. PMID:29770325

Linking Supply Chain Governance and Biosecurity in the Context of HPAI Control in Western Java: A Value Chain Perspective.

PubMed

Indrawan, Dikky; Rich, Karl M; van Horne, Peter; Daryanto, Arief; Hogeveen, Henk

2018-01-01

Despite extensive efforts to control the highly pathogenic avian influenza (HPAI), it remains endemic in Western Java, Indonesia. To understand the limited effectiveness of HPAI control measures, it is important to map the complex structure of the poultry sector. The governance of the poultry value chain in particular, could play a pivotal role, yet there is limited information on the different chain governance structures and their impacts on HPAI control. This article uses value chain analysis (VCA), focusing on an in-depth assessment of governance structures as well as transaction cost economics and quantitative estimates of the market power of different chain actors, to establish a theoretical framework to examine biosecurity and HPAI control in the Western Java poultry chain. During the research, semi-structured interviews were conducted with key value-chain stakeholders, and the economic performance of identified actors was estimated. Results indicated the co-existence of four different poultry value chains in West Java: the integrator chain, the semi-automated slaughterhouse chain, the controlled slaughter-point chain, and the private slaughter-point chain. The integrator chain was characterized by the highest levels of coordination and a tight, hierarchical governance. In contrast, the other three types of value chains were less coordinated. The market power of the different actors within the four value chains also differed. In more integrated chains, slaughterhouses held considerable market power, while in more informal value chains, market power was in the hands of traders. The economic effects of HPAI and biosecurity measures also varied for the identified actors in the different value chains. Implementation of biosecurity and HPAI control measures was strongly related to the governance structure of the chain, with interactions between different chains and governance structures accentuating the risk of HPAI. Our findings highlight that a proper understanding of the chain governance structure is vital to improve the effectiveness of HPAI control measures, by making the interventions more specific and fit-for-purpose given the incentive structures present in different chains.

The association of hospital governance with innovation in Taiwan.

PubMed

Yang, Chen-Wei; Yan, Yu-Hua; Fang, Shih-Chieh; Inamdar, Syeda Noorein; Lin, Hsien-Cheng

2018-01-01

Hospitals in Taiwan are facing major changes and innovation is increasingly becoming a critical factor for remaining competitive. One determinant that can have a significant impact on innovation is hospital governance. However, there is limited prior research on the relationship between hospital governance and innovation. The purpose of this study is to propose a conceptual framework to hypothesize the relationship between governance mechanisms and innovation and to empirically test the hypotheses in hospital organizations. We examine the relationship between governance mechanisms and innovation using data on 102 hospitals in Taiwan from the Taiwan Joint Commission on Hospital Accreditation and Quality Improvement. We model governance mechanisms using board structure, information transparency and strategic decision-making processes. For our modeling and data analysis we use measurement and structural models. We find that in hospital governance, information transparency and strategic decision making did impact innovation. However, governance structure did not. To facilitate innovation, hospital boards can increase information transparency and improve the decision-making process when considering strategic investments in innovative initiatives. To remain competitive, hospital boards need to develop and monitor indices that measure hospital innovation to ensure ongoing progress. Copyright © 2017 John Wiley & Sons, Ltd.

Hydrothermal performance of catalyst supports

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elam, Jeffrey W.; Marshall, Christopher L.; Libera, Joseph A.

A high surface area catalyst with a mesoporous support structure and a thin conformal coating over the surface of the support structure. The high surface area catalyst support is adapted for carrying out a reaction in a reaction environment where the thin conformal coating protects the support structure within the reaction environment. In various embodiments, the support structure is a mesoporous silica catalytic support and the thin conformal coating comprises a layer of metal oxide resistant to the reaction environment which may be a hydrothermal environment.

First determination of volume changes and enthalpies of the high-pressure decomposition reaction of the structure H methane hydrate to the cubic structure I methane hydrate and fluid methane.

PubMed

Ogienko, Andrey G; Tkacz, Marek; Manakov, Andrey Yu; Lipkowski, Janusz

2007-11-08

Pressure-temperature (P-T) conditions of the decomposition reaction of the structure H high-pressure methane hydrate to the cubic structure I methane hydrate and fluid methane were studied with a piston-cylinder apparatus at room temperature. For the first time, volume changes accompanying this reaction were determined. With the use of the Clausius-Clapeyron equation the enthalpies of the decomposition reaction of the structure H high-pressure methane hydrate to the cubic structure I methane hydrate and fluid methane have been calculated.

RxnFinder: biochemical reaction search engines using molecular structures, molecular fragments and reaction similarity.

PubMed

Hu, Qian-Nan; Deng, Zhe; Hu, Huanan; Cao, Dong-Sheng; Liang, Yi-Zeng

2011-09-01

Biochemical reactions play a key role to help sustain life and allow cells to grow. RxnFinder was developed to search biochemical reactions from KEGG reaction database using three search criteria: molecular structures, molecular fragments and reaction similarity. RxnFinder is helpful to get reference reactions for biosynthesis and xenobiotics metabolism. RxnFinder is freely available via: http://sdd.whu.edu.cn/rxnfinder. qnhu@whu.edu.cn.

Matching safety to access: global actors and pharmacogovernance in Kenya- a case study.

PubMed

Moscou, Kathy; Kohler, Jillian C

2017-03-23

The Kenyan government has sought to address inadequacies in its National Pharmaceutical Policy and the Pharmacy and Poisons Board's (PPB) medicines governance by engaging with global actors (e.g. the World Health Organization). Policy actors have influenced the way pharmacovigilance is defined, how challenges are understood and which norms are requisite to address drug safety issues. In this paper, we investigate the relationship between specific modes of engagement among global (exogenous) and domestic actors at the national and sub-national level to identify the positive or negative effect on pharmacovigilance and pharmacogovernance in Kenya. Pharmacogovernance is defined as the manner in which governing structures; policy instruments; institutional authority (e.g., ability to act, implement and enforce norms, policies and processes) and resources are managed to promote societal interests for patient safety and protection from adverse drug reactions (ADRs). Qualitative research methods that included key informant interviews and document analysis, were employed to investigate the relationship between global actors' patterns of engagement with national actors and pharmacogovernance in Kenya. Global actors' influence on pharmacogovernance and pharmacovigilance priorities in Kenya (e.g., legislation and adverse drug reaction surveillance) was positively perceived by key informants. We found that global actors' engagement with state actors produced positive and negative outcomes. Engagement with the PPB and Ministry of Health (MOH) that was characterized as dependent (advocacy, empowerment, delegated) or interdependent (collaborative, cooperative, consultative) was mostly associated with positive outcomes e.g., capacity building; strengthening legislation and stakeholder coordination. Fragmentation (independent engagement) hindered risk communication between public, private, and NGO health programs. A framework for assessing pharmacogovernance would support policy makers' evidence-based decision making regarding investments to strengthen capacity for pharmacovigilance and guide policies regarding the state and exogenous actor relationship pertaining to pharmacogovernance. Ideally, dependency on exogenous actors should be reduced while retaining consultative, collaborative, and cooperative engagement when inter-dependency is appropriate. The use of global actors to address Kenya's pharmacovigilance inadequacies leaves the country vulnerable to 1) ad hoc drug surveillance; 2) pharmacovigilance fragmentation; 3) shifting priorities; and 4) cross purpose interests.

Intricate Li-Sn Disorder in Rare-Earth Metal-Lithium Stannides. Crystal Chemistry of RE3Li4- xSn4+ x (RE = La-Nd, Sm; x < 0.3) and Eu7Li8- xSn10+ x ( x ≈ 2.0).

PubMed

Suen, Nian-Tzu; Guo, Sheng-Ping; Hoos, James; Bobev, Svilen

2018-05-07

Reported are the syntheses, crystal structures, and electronic structures of six rare-earth metal-lithium stannides with the general formulas RE 3 Li 4- x Sn 4+ x (RE = La-Nd, Sm) and Eu 7 Li 8- x Sn 10+ x . These new ternary compounds have been synthesized by high-temperature reactions of the corresponding elements. Their crystal structures have been established using single-crystal X-ray diffraction methods. The RE 3 Li 4- x Sn 4+ x phases crystallize in the orthorhombic body-centered space group Immm (No. 71) with the Zr 3 Cu 4 Si 4 structure type (Pearson code oI22), and the Eu 7 Li 8- x Sn 10+ x phase crystallizes in the orthorhombic base-centered space group Cmmm (No. 65) with the Ce 7 Li 8 Ge 10 structure type (Pearson code oC50). Both structures can be consdered as part of the [RESn 2 ] n [RELi 2 Sn] m homologous series, wherein the structures are intergrowths of imaginary RESn 2 (AlB 2 -like structure type) and RELi 2 Sn (MgAl 2 Cu-like structure type) fragments. Close examination the structures indicates complex occupational Li-Sn disorder, apparently governed by the drive of the structure to achieve an optimal number of valence electrons. This conclusion based on experimental results is supported by detailed electronic structure calculations, carried out using the tight-binding linear muffin-tin orbital method.

Interface Reactions and Synthetic Reaction of Composite Systems

PubMed Central

Park, Joon Sik; Kim, Jeong Min

2010-01-01

Interface reactions in composite systems often determine their overall properties, since product phases usually formed at interfaces during composite fabrication processing make up a large portion of the composites. Since most composite materials represent a ternary or higher order materials system, many studies have focused on analyses of diffusion phenomena and kinetics in multicomponent systems. However, the understanding of the kinetic behavior increases the complexity, since the kinetics of each component during interdiffusion reactions need to be defined for interpreting composite behaviors. From this standpoint, it is important to clarify the interface reactions for producing compatible interfaces with desired product phases. A thermodynamic evaluation such as a chemical potential of involving components can provide an understanding of the diffusion reactions, which govern diffusion pathways and product phase formation. A strategic approach for designing compatible interfaces is discussed in terms of chemical potential diagrams and interface morphology, with some material examples.

Real-space and real-time observation of a plasmon-induced chemical reaction of a single molecule.

PubMed

Kazuma, Emiko; Jung, Jaehoon; Ueba, Hiromu; Trenary, Michael; Kim, Yousoo

2018-05-04

Plasmon-induced chemical reactions of molecules adsorbed on metal nanostructures are attracting increased attention for photocatalytic reactions. However, the mechanism remains controversial because of the difficulty of direct observation of the chemical reactions in the plasmonic field, which is strongly localized near the metal surface. We used a scanning tunneling microscope (STM) to achieve real-space and real-time observation of a plasmon-induced chemical reaction at the single-molecule level. A single dimethyl disulfide molecule on silver and copper surfaces was dissociated by the optically excited plasmon at the STM junction. The STM study combined with theoretical calculations shows that this plasmon-induced chemical reaction occurred by a direct intramolecular excitation mechanism. Copyright © 2018 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works.

A Reaction Between High Mn-High Al Steel and CaO-SiO2-Type Molten Mold Flux: Part I. Composition Evolution in Molten Mold Flux

NASA Astrophysics Data System (ADS)

Kim, Min-Su; Lee, Su-Wan; Cho, Jung-Wook; Park, Min-Seok; Lee, Hae-Geon; Kang, Youn-Bae

2013-04-01

In order to elucidate the reaction mechanism between high Mn-high Al steel such as twin-induced plasticity steel and molten mold flux composed mainly of CaO-SiO2 during continuous casting process, a series of laboratory-scale experiments were carried out in the present study. Molten steel and molten flux were brought to react in a refractory crucible in a temperature range between 1713 K to 1823 K (1440 °C to 1550 °C) and composition evolution in the steel and the flux was analyzed using inductively coupled plasma atomic emission spectroscopy, X-ray fluorescence, and electron probe microanalysis. The amount of SiO2 in the flux was significantly reduced by Al in the steel; thus, Al2O3 was accumulated in the flux as a result of a chemical reaction, 4[Al] + 3(SiO2) = 3[Si] + 2(Al2O3). In order to find a major factor which governs the reaction, a number of factors ((pct CaO/pct SiO2), (pct Al2O3), [pct Al], [pct Si], and temperature) were varied in the experiments. It was found that the above chemical reaction was mostly governed by [pct Al] in the molten steel. Temperature had a mild effect on the reaction. On the other hand, (pct CaO/pct SiO2), (pct Al2O3), and [pct Si] did not show any noticeable effect on the reaction. Apart from the above reaction, the following reactions are also thought to happen simultaneously: 2[Mn] + (SiO2) = [Si] + 2(MnO) and 2[Fe] + (SiO2) = [Si] + 2(FeO). These oxide components were subsequently reduced by Al in the molten steel. Na2O in the molten flux was gradually decreased and the decrease was accelerated by increasing [pct Al] and temperature. Possible reactions affecting the Al2O3 accumulation are summarized.

The Structures of Centralized Governmental Privacy Protection: Approaches, Models, and Analysis.

ERIC Educational Resources Information Center

Jaeger, Paul T.; McClure, Charles R.; Fraser, Bruce T.

2002-01-01

Asserts that the federal government should adopt a centralized governmental structure for the privacy protection of personal information and data. Discusses the roles of federal law, federal agencies, and the judiciary; the concept of information privacy; the impact of current technologies; and models of centralized government structures for…

An experimental and kinetic investigation of premixed furan/oxygen/argon flames

PubMed Central

Tian, Zhenyu; Yuan, Tao; Fournet, Rene; Glaude, Pierre-Alexandre; Sirjean, Baptiste; Battin-Leclerc, Frédérique; Zhang, Kuiwen; Qi, Fei

2013-01-01

The detailed chemical structures of three low-pressure (35 Torr) premixed laminar furan/oxygen/argon flames with equivalence ratios of 1.4, 1.8 and 2.2 have been investigated by using tunable synchrotron vacuum ultraviolet (VUV) photoionization and molecular-beam mass spectrometry. About 40 combustion species including hydrocarbons and oxygenated intermediates have been identified by measurements of photoionization efficiency spectra. Mole fraction profiles of the flame species including reactants, intermediates and products have been determined by scanning burner position with some selected photon energies near ionization thresholds. Flame temperatures have been measured by a Pt-6%Rh/Pt-30%Rh thermocouple. A new mechanism involving 206 species and 1368 reactions has been proposed whose predictions are in reasonable agreement with measured species profiles for the three investigated flames. Rate-of-production and sensitivity analyses have been performed to track the key reaction paths governing furan consumption for different equivalence ratios. Both experimental and modeling results indicate that few aromatics could be formed in these flames. Furthermore, the current model has been validated against previous pyrolysis results of the literature obtained behind shock waves and the agreement is reasonable as well. PMID:23814311

An experimental and kinetic investigation of premixed furan/oxygen/argon flames.

PubMed

Tian, Zhenyu; Yuan, Tao; Fournet, Rene; Glaude, Pierre-Alexandre; Sirjean, Baptiste; Battin-Leclerc, Frédérique; Zhang, Kuiwen; Qi, Fei

2011-04-01

The detailed chemical structures of three low-pressure (35 Torr) premixed laminar furan/oxygen/argon flames with equivalence ratios of 1.4, 1.8 and 2.2 have been investigated by using tunable synchrotron vacuum ultraviolet (VUV) photoionization and molecular-beam mass spectrometry. About 40 combustion species including hydrocarbons and oxygenated intermediates have been identified by measurements of photoionization efficiency spectra. Mole fraction profiles of the flame species including reactants, intermediates and products have been determined by scanning burner position with some selected photon energies near ionization thresholds. Flame temperatures have been measured by a Pt-6%Rh/Pt-30%Rh thermocouple. A new mechanism involving 206 species and 1368 reactions has been proposed whose predictions are in reasonable agreement with measured species profiles for the three investigated flames. Rate-of-production and sensitivity analyses have been performed to track the key reaction paths governing furan consumption for different equivalence ratios. Both experimental and modeling results indicate that few aromatics could be formed in these flames. Furthermore, the current model has been validated against previous pyrolysis results of the literature obtained behind shock waves and the agreement is reasonable as well.

Voltammetric Perspectives on the Acidity Scale and H+/H2 Process in Ionic Liquid Media.

PubMed

Bentley, Cameron L; Bond, Alan M; Zhang, Jie

2018-03-19

Nonhaloaluminate ionic liquids (ILs) have received considerable attention as alternatives to molecular solvents in diverse applications spanning the fields of physical, chemical, and biological science. One important and often overlooked aspect of the implementation of these designer solvents is how the properties of the IL formulation affect (electro)chemical reactivity. This aspect is emphasized herein, where recent (voltammetric) studies on the energetics of proton (H + ) transfer and electrode reaction mechanisms of the H + H 2 process in IL media are highlighted and discussed. The energetics of proton transfer, quantified using the pK 3 a (minus logarithm of acidity equilibrium constant, K a ) formalism, is strongly governed by the constituent IL anion, and to a lesser extent, the IL cation. The H + /H 2 process, a model inner-sphere reaction, also displays electrochemical characteristics that are strongly IL-dependent. Overall, these studies highlight the need to carry out systematic investigations to resolve IL structure and function relationships in order to realize the potential of these diverse and versatile solvents. Expected final online publication date for the Annual Review of Analytical Chemistry Volume 11 is June 12, 2018. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

The effect of carbon-chain oxygenation in the carbon-carbon dissociation.

PubMed

Dos Santos, Lisandra Paulino; Baptista, Leonardo

2018-06-01

Currently, there is a trend of moving away from the use of fossil fuels to the use of biofuels. This modification changes the molecular structure of gasoline and diesel constituents, which should impact pollutant emissions and engine efficiency. An important property of automotive fuels is the resistance to autoignition. The goal of the present work is to evaluate thermochemical and kinetic parameters that govern the carbon-carbon bond dissociation and relate these parameters, in conjunction with molecular properties, to autoignition resistance. Three model reactions were investigated in the present work: dissociation of ethane, ethanol, and ethanal. All studies were conducted at the multiconfigurational level of theory, and the rate coefficients were evaluated from 300 to 2000 K. The comparison of dissociation energies and Arrhenius expressions indicates that autoignition resistance is related to the kinetic control of dissociation reactions and it is possible to relate the higher octane number of ethanol based fuels to the kinetics parameters of carbon-carbon bond fission. Graphical abstract Effect of the functional group in the Arrhenius parameters of the C-C dissociation. Arrhenius curves calculated at NEVPT2(6,6)/6-311G(2df,2pd).

Balancing stability and flexibility in adaptive governance: an ...

EPA Pesticide Factsheets

Adaptive governance must work “on the ground,” that is, it must operate through structures and procedures that the people it governs perceive to be legitimate and fair, as well as incorporating processes and substantive goals that are effective in allowing social-ecological systems (SESs) to adapt to climate change and other impacts. To address the continuing and accelerating alterations that climate change is bringing to SESs, adaptive governance generally will require more flexibility than prior governance institutions have often allowed. However, to function as good governance, adaptive governance must pay real attention to the problem of how to balance this increased need for flexibility with continuing governance stability so that it can foster adaptation to change without being perceived or experienced as perpetually destabilizing, disruptive, and unfair. Flexibility and stability serve different purposes in governance, and a variety of tools exist to strike different balances between them while still preserving the governance institution’s legitimacy among the people governed. After reviewing those purposes and the implications of climate change for environmental governance, we examine psychological insights into the structuring of adaptive governance and the variety of legal tools available to incorporate those insights into adaptive governance regimes. Because the substantive goals of governance systems will differ among specific systems, we do no

Homogeneous-heterogeneous reactions in curved channel with porous medium

NASA Astrophysics Data System (ADS)

Hayat, T.; Ayub, Sadia; Alsaedi, A.

2018-06-01

Purpose of the present investigation is to examine the peristaltic flow through porous medium in a curved conduit. Problem is modeled for incompressible electrically conducting Ellis fluid. Influence of porous medium is tackled via modified Darcy's law. The considered model utilizes homogeneous-heterogeneous reactions with equal diffusivities for reactant and autocatalysis. Constitutive equations are formulated in the presence of viscous dissipation. Channel walls are compliant in nature. Governing equations are modeled and simplified under the assumptions of small Reynolds number and large wavelength. Graphical results for velocity, temperature, heat transfer coefficient and homogeneous-heterogeneous reaction parameters are examined for the emerging parameters entering into the problem. Results reveal an activation in both homogenous-heterogenous reaction effect and heat transfer rate with increasing curvature of the channel.

Studies in Public Welfare. Paper No. 12 (Part II): The Family, Poverty and Welfare Programs--Household Patterns and Government Policies.

ERIC Educational Resources Information Center

Joint Economic Committee, Washington, DC.

The papers in this volume deal with patterns of household composition and income sharing among low-income families as well as current and proposed Government policies directly related to family structure. Government policies relevant to family structure make up one set of topics. Irene Cox describes how public income transfer benefits and…

The Pendulum Strikes Back? An Analysis of the Evolution of Hungarian Higher Education Governance and Organisational Structures since the 1980s

ERIC Educational Resources Information Center

Kováts, Gergely; Heidrich, Balázs; Chandler, Nick

2017-01-01

Higher education in Central Europe has been scrutinised from many different perspectives during the last 30 years. In our analysis, we focus solely on Hungary and specifically on two key areas: governance and organisational structure. Using an analytical model proposed by Leisyte (2014), we analyse how the governance and organisational structure…

Protoenzymes: the case of hyperbranched polyesters

NASA Astrophysics Data System (ADS)

Mamajanov, Irena; Cody, George D.

2017-11-01

Enzymes are biopolymeric complexes that catalyse biochemical reactions and shape metabolic pathways. Enzymes usually work with small molecule cofactors that actively participate in reaction mechanisms and complex, usually globular, polymeric structures capable of specific substrate binding, encapsulation and orientation. Moreover, the globular structures of enzymes possess cavities with modulated microenvironments, facilitating the progression of reaction(s). The globular structure is ensured by long folded protein or RNA strands. Synthesis of such elaborate complexes has proven difficult under prebiotically plausible conditions. We explore here that catalysis may have been performed by alternative polymeric structures, namely hyperbranched polymers. Hyperbranched polymers are relatively complex structures that can be synthesized under prebiotically plausible conditions; their globular structure is ensured by virtue of their architecture rather than folding. In this study, we probe the ability of tertiary amine-bearing hyperbranched polyesters to form hydrophobic pockets as a reaction-promoting medium for the Kemp elimination reaction. Our results show that polyesters formed upon reaction between glycerol, triethanolamine and organic acid containing hydrophobic groups, i.e. adipic and methylsuccinic acid, are capable of increasing the rate of Kemp elimination by a factor of up to 3 over monomeric triethanolamine. This article is part of the themed issue 'Reconceptualizing the origins of life'.

A mathematical model for foreign body reactions in 2D.

PubMed

Su, Jianzhong; Gonzales, Humberto Perez; Todorov, Michail; Kojouharov, Hristo; Tang, Liping

2011-02-01

The foreign body reactions are commonly referred to the network of immune and inflammatory reactions of human or animals to foreign objects placed in tissues. They are basic biological processes, and are also highly relevant to bioengineering applications in implants, as fibrotic tissue formations surrounding medical implants have been found to substantially reduce the effectiveness of devices. Despite of intensive research on determining the mechanisms governing such complex responses, few mechanistic mathematical models have been developed to study such foreign body reactions. This study focuses on a kinetics-based predictive tool in order to analyze outcomes of multiple interactive complex reactions of various cells/proteins and biochemical processes and to understand transient behavior during the entire period (up to several months). A computational model in two spatial dimensions is constructed to investigate the time dynamics as well as spatial variation of foreign body reaction kinetics. The simulation results have been consistent with experimental data and the model can facilitate quantitative insights for study of foreign body reaction process in general.

Autonomous colloidal crystallization in a galvanic microreactor

NASA Astrophysics Data System (ADS)

Punckt, Christian; Jan, Linda; Jiang, Peng; Frewen, Thomas A.; Saville, Dudley A.; Kevrekidis, Ioannis G.; Aksay, Ilhan A.

2012-10-01

We report on a technique that utilizes an array of galvanic microreactors to guide the assembly of two-dimensional colloidal crystals with spatial and orientational order. Our system is comprised of an array of copper and gold electrodes in a coplanar arrangement, immersed in a dilute hydrochloric acid solution in which colloidal micro-spheres of polystyrene and silica are suspended. Under optimized conditions, two-dimensional colloidal crystals form at the anodic copper with patterns and crystal orientation governed by the electrode geometry. After the aggregation process, the colloidal particles are cemented to the substrate by co-deposition of reaction products. As we vary the electrode geometry, the dissolution rate of the copper electrodes is altered. This way, we control the colloidal motion as well as the degree of reaction product formation. We show that particle motion is governed by a combination of electrokinetic effects acting directly on the colloidal particles and bulk electrolyte flow generated at the copper-gold interface.

Psychological reactions to redress: diversity among Japanese Americans interned during World War II.

PubMed

Nagata, Donna K; Takeshita, Yuzuru J

2002-02-01

The psychological reactions of 2nd-generation (Nisei) Japanese Americans to receiving redress from the U.S. government for the injustices of their World War II internment were investigated. The respondents, all of whom had been interned during the war, rated the degree to which the receipt of redress nearly 50 years after their incarceration was associated with 8 different areas of personal impact. Results indicated that redress was reported to be most effective in increasing faith in the government and least effective in reducing physical suffering from the internment. Women and older respondents reported more positive redress effects. In addition, lower levels of current income, an attitudinal preference for Japanese Americans, and preredress support for seeking monetary compensation each increased the prediction of positive redress effects. Findings are discussed in relation to theories of social and retributive justice.

A two-dimensional numerical simulation of a supersonic, chemically reacting mixing layer

NASA Technical Reports Server (NTRS)

Drummond, J. Philip

1988-01-01

Research has been undertaken to achieve an improved understanding of physical phenomena present when a supersonic flow undergoes chemical reaction. A detailed understanding of supersonic reacting flows is necessary to successfully develop advanced propulsion systems now planned for use late in this century and beyond. In order to explore such flows, a study was begun to create appropriate physical models for describing supersonic combustion, and to develop accurate and efficient numerical techniques for solving the governing equations that result from these models. From this work, two computer programs were written to study reacting flows. Both programs were constructed to consider the multicomponent diffusion and convection of important chemical species, the finite rate reaction of these species, and the resulting interaction of the fluid mechanics and the chemistry. The first program employed a finite difference scheme for integrating the governing equations, whereas the second used a hybrid Chebyshev pseudospectral technique for improved accuracy.

Preliminary study of the effects of a reversible chemical reaction on gas bubble dissolution. [for space glass refining

NASA Technical Reports Server (NTRS)

Weinberg, M. C.

1982-01-01

A preliminary investigation is carried out of the effects of a reversible chemical reaction on the dissolution of an isolated, stationary gas bubble in a glass melt. The exact governing equations for the model system are formulated and analyzed. The approximate quasi-steady-state version of these equations is solved analytically, and a calculation is made of bubble dissolution rates. The results are then compared with numerical solutions obtained from the finite difference form of the exact governing equations. It is pointed out that in the microgravity condition of space, the buoyant rise of a gas bubble in a glass melt will be negligible on the time scale of most experiments. For this reason, a determination of the behavior of a stationary gas bubble in a melt is relevant for an understanding of glass refining in space.

Panel: Governance in Open Source Projects and Communities

NASA Astrophysics Data System (ADS)

Bolici, Francesco; de Laat, Paul; Ljungberg, Jan; Pontiggia, Andrea; Rossi Lamastra, Cristina

“Although considerable research has been devoted to the growth and expansion of open source communities and the comparison between the efficiency of corporate structures and community structures in the field of software development, rather less attention has been paid to their governance structures (control, monitoring, supervision)” (Lattemann and Stieglitz 2005).

Nominations please! Or how a multi singled out potential trustees.

PubMed

McMurry, P V

1984-11-01

As multihospital systems become more geographically diversified, it can be increasingly difficult to maintain an effective, systemwide governance structure. This article describes the governance structure that Baptist Hospitals and Health Systems, Phoenix, has in place, and how it successfully duplicated that structure in a large county hospital it recently acquired in Florida.

Structural Evolution of Nanoscale Zero-Valent Iron (nZVI) in Anoxic Co2+Soultion : Interactional Performance and Mechanism

NASA Astrophysics Data System (ADS)

Dai, C.; Zhang, Y.

2015-12-01

The nanoscale particle and low oxidation reduction potential make nano zero-valent iron (nZVI) an efficient sorbent and reductant for treating many kinds of organic contaminants and heavy metals.The structures of nanoscale zero-valent iron (nZVI) particles are evolving in reactions, and the reactions are influenced by the evolved structures. In order to understand the detail removal process, it is important to investigate the interactions between reactions and structural evolution. In this work, reactions between nZVI and Co2+ at different initial concentrations in anoxic aqueous solutions (to eliminate the effects of O2) were tracked for 10 days using a variety of methods including inductively coupled plasma optical emission spectrometry (ICP-OES), high resolution-transmission electron microscopy (HR-TEM), energy dispersive spectrometer (EDS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM). Continuous removal and reduction of Co2+ by nZVI caused by structural evolution were revealed in reaction processes. The system pH (pH measured in mixture), which controls the stability of coprecipitation and the corrosion rate of nZVI, was deemed as the determining factors of structural evolutions. X-ray photoelectron spectroscopy (XPS) results showed that the formation and dissolution of sheet structure impacts on the ratio of Fe (0) on nZVI's surface and the surface reduction of Co2+. The cavity structure provides the possibility of Co migrating from surface to inside of nZVI leading a continuous removal. A subacidity condition could accelerate the evolution to improve the removal of Co2+ and the results of structural controlled reactions further indicated that the removal was suspended by sheet structure and enhanced by cavity structure. The results in this study revealed "structural influence" for fully and dynamically understanding nZVI's reactions.

Following radical pair reactions in solution: a step change in sensitivity using cavity ring-down detection.

PubMed

Maeda, Kiminori; Neil, Simon R T; Henbest, Kevin B; Weber, Stefan; Schleicher, Erik; Hore, P J; Mackenzie, Stuart R; Timmel, Christiane R

2011-11-09

The study of radical pair intermediates in biological systems has been hampered by the low sensitivity of the optical techniques usually employed to investigate these highly reactive species. Understanding the physical principles governing the spin-selective and magneto-sensitive yields and kinetics of their reactions is essential in identifying the mechanism governing bird migration, and might have significance in the discussion of potential health hazards of electromagnetic radiation. Here, we demonstrate the powerful capabilities of optical cavity-enhanced techniques, such as cavity ring-down spectroscopy (CRDS) in monitoring radical recombination reactions and associated magnetic field effects (MFEs). These include submicrosecond time-resolution, high sensitivity (baseline noise on the order of 10(-6) absorbance units) and small (μL) sample volumes. Combined, we show that these represent significant advantages over the single-pass flash-photolysis techniques conventionally applied. The studies described here focus on photoinduced radical pair reactions involving the protein lysozyme and one of two possible photosensitizers: anthraquinone-2,6-disulphonate and flavin mononucleotide. CRDS-measured MFEs are observed in pump-probe experiments and discussed in terms of the sensitivity gains and sample-volume minimization afforded by CRDS when compared with flash photolysis methods. Finally, CRDS is applied to an in vitro MFE study of intramolecular electron transfer in the DNA-repair enzyme, Escherichia coli photolyase, a protein closely related to cryptochrome which has been proposed to mediate animal magnetoreception.

Dynamic adaptive chemistry with operator splitting schemes for reactive flow simulations

NASA Astrophysics Data System (ADS)

Ren, Zhuyin; Xu, Chao; Lu, Tianfeng; Singer, Michael A.

2014-04-01

A numerical technique that uses dynamic adaptive chemistry (DAC) with operator splitting schemes to solve the equations governing reactive flows is developed and demonstrated. Strang-based splitting schemes are used to separate the governing equations into transport fractional substeps and chemical reaction fractional substeps. The DAC method expedites the numerical integration of reaction fractional substeps by using locally valid skeletal mechanisms that are obtained using the directed relation graph (DRG) reduction method to eliminate unimportant species and reactions from the full mechanism. Second-order temporal accuracy of the Strang-based splitting schemes with DAC is demonstrated on one-dimensional, unsteady, freely-propagating, premixed methane/air laminar flames with detailed chemical kinetics and realistic transport. The use of DAC dramatically reduces the CPU time required to perform the simulation, and there is minimal impact on solution accuracy. It is shown that with DAC the starting species and resulting skeletal mechanisms strongly depend on the local composition in the flames. In addition, the number of retained species may be significant only near the flame front region where chemical reactions are significant. For the one-dimensional methane/air flame considered, speed-up factors of three and five are achieved over the entire simulation for GRI-Mech 3.0 and USC-Mech II, respectively. Greater speed-up factors are expected for larger chemical kinetics mechanisms.

Governance Structures for Open Innovation: A Preliminary Framework

NASA Astrophysics Data System (ADS)

Feller, Joseph; Finnegan, Patrick; Hayes, Jeremy; O'Reilly, Philip

This research-in-progress paper presents a preliminary framework of four open innovation governance structures. The study seeks to describe four distinct ways in which firms utilize hierarchical relationships, organizational intermediaries, and the market system to supply and acquire intellectual property and/or innovation capabilities from sources external to the firm. This paper reports on phase one of the study, which involved an analysis of six open innovation exemplars based on public data. This phase of the study reveals that governance structures for open innovation can be categorized based on whether they (1) are mediated or direct or (2) seek to acquire intellectual property or innovation capability. We analyze the differences in four governance structures along seven dimensions, and reveal the importance of knowledge dispersion and uncertainty to the use of open innovation hierarchies, brokerages, and markets. The paper concludes by examining the implications of the findings and outlining the next phase of the study.

Reforming the Governance of California Community Colleges.

ERIC Educational Resources Information Center

Nussbaum, Thomas J.

In this speech, Chancellor Thomas J. Nussbaum defends the existence of local governing boards for community colleges and offers suggestions for improving the current weak governance structure. He argues that doing away with local governing boards would: (1) create a greater inconsistency between the mission and the governance of the colleges; (2)…

[What to do? The Ontario government and the illegal recreational use of drugs, 1966-1972].

PubMed

Martel, Marcel

2003-01-01

This paper deals with the social construction of illegal drug use in the context of the counterculture movement. It looks at the actions and reactions of three groups in particular: the Ontario government, the Addiction Research Foundation of Ontario and citizens. It demonstrates that the debate about drug use took place in particular circumstances characterized by ignorance about the health consequences of illegal drug use but also within a moral panic context. Medical expertise was solicited to provide guidance to the Ontario government but it was gradually challenged by other medical groups and citizens who, by sending letters to their Provincial Premier and the Minister of Health, tried to shape public policy.

Scientific Citizenship and good governance: implications for biotechnology.

PubMed

Davies, Keith G; Wolf-Phillips, Jonathan

2006-02-01

In the wake of public distrust regarding biotechnology, it has been suggested that the debate should be moved "upstream", whereby the public help to set research priorities. Although many scientists see this as an illogical reaction to a loss of faith in science, we argue that the boundaries between science and its technological applications have become blurred and this produces conflicts of interests that have led to this crisis of trust. Furthermore, this distrust is also a crisis in governance that calls for a new open and democratic approach to scientific research. We propose that the concept of Scientific Citizenship, based on good governance, will help to restore public trust and bridge the gap between science and the society that it serves. Integral to this is the suggestion that the governance of science forms part of the training for scientists.

Ab initio study of perovskite type oxide materials for solid oxide fuel cells

NASA Astrophysics Data System (ADS)

Lee, Yueh-Lin

2011-12-01

Perovskite type oxides form a family of materials of significant interest for cathodes and electrolytes of solid oxide fuel cells (SOFCs). These perovskites not only are active catalysts for surface oxygen reduction (OR) reactions but also allow incorporating the spilt oxygen monomers into their bulk, an unusual and poorly understood catalytic mechanism that couples surface and bulk properties. The OR mechanisms can be influenced strongly by defects in perovskite oxides, composition, and surface defect structures. This thesis work initiates a first step in developing a general strategy based on first-principles calculations for detailed control of oxygen vacancy content, transport rates of surface and bulk oxygen species, and surface/interfacial reaction kinetics. Ab initio density functional theory methods are used to model properties relevant for the OR reactions on SOFC cathodes. Three main research thrusts, which focus on bulk defect chemistry, surface defect structures and surface energetics, and surface catalytic properties, are carried to investigate different level of material chemistry for improved understanding of key physics/factors that govern SOFC cathode OR activity. In the study of bulk defect chemistry, an ab initio based defect model is developed for modeling defect chemistry of LaMnO 3 under SOFC conditions. The model suggests an important role for defect interactions, which are typically excluded in previous defect models. In the study of surface defect structures and surface energetics, it is shown that defect energies change dramatically (1˜2 eV lower) from bulk values near surfaces. Based on the existing bulk defect model with the calculated ab initio surface defect energetics, we predict the (001) MnO 2 surface oxygen vacancy concentration of (La0.9Sr0.1 )MnO3 is about 5˜6 order magnitude higher than that of the bulk under typical SOFC conditions. Finally, for surface catalytic properties, we show that area specific resistance, oxygen exchange rates, and key OR energetics of the SOFC cathode perovskites, can be described by a single descriptor, either the bulk O p-band or the bulk oxygen vacancy formation energy. These simple descriptors will further enable first-principles optimization/design of new SOFC cathodes.

Application of combinatorial biocatalysis for a unique ring expansion of dihydroxymethylzearalenone.

PubMed

Rich, Joseph O; Budde, Cheryl L; McConeghey, Luke D; Cotterill, Ian C; Mozhaev, Vadim V; Singh, Sheo B; Goetz, Michael A; Zhao, Annie; Michels, Peter C; Khmelnitsky, Yuri L

2009-06-01

Combinatorial biocatalysis was applied to generate a diverse set of dihydroxymethylzearalenone analogs with modified ring structure. In one representative chemoenzymatic reaction sequence, dihydroxymethylzearalenone was first subjected to a unique enzyme-catalyzed oxidative ring opening reaction that creates two new carboxylic groups on the molecule. These groups served as reaction sites for further derivatization involving biocatalytic ring closure reactions with structurally diverse bifunctional reagents, including different diols and diamines. As a result, a library of cyclic bislactones and bislactams was created, with modified ring structures covering chemical space and structure activity relationships unattainable by conventional synthetic means.

Nuclear Power in Japan.

ERIC Educational Resources Information Center

Powell, John W.

1983-01-01

Energy consumption in Japan has grown at a faster rate than in any other major industrial country. To maintain continued prosperity, the government has embarked on a crash program for nuclear power. Current progress and issues/reactions to the plan are discussed. (JN)

Structural Evolution of Nanoscale Zero-Valent Iron (nZVI) in Anoxic Co2+ Solution: Interactional Performance and Mechanism

PubMed Central

Zhang, Yalei; Chen, Wen; Dai, Chaomeng; Zhou, Chuanlong; Zhou, Xuefei

2015-01-01

The structures of nanoscale zero-valent iron (nZVI) particles evolving during reactions, and the reactions are influenced by the evolved structures. To understand the removal process in detail, it is important to investigate the relationships between the reactions and structural evolution. Using high resolution-transmission electron microscopy (HR-TEM), typical evolved structures (sheet coprecipitation and cavity corrosion) of nZVI in anoxic Co2+ solutions were revealed. The system pH (pH measured in mixture), which controls the stability of coprecipitation and the nZVI corrosion rate, were found to be the determining factors of structural evolutions. X-ray photoelectron spectroscopy (XPS) results indicated that the formation and dissolution of sheet structure impacts on the ratio of Fe(0) on the nZVI surface and the surface Co2+ reduction. The cavity structure provides the possibility of Co migration from the surface to the bulk of nZVI, leading to continuous removal. Subacidity conditions could accelerate the evolution and improve the removal; the results of structurally controlled reactions further indicated that the removal was suspended by the sheet structure and enhanced by cavity structure. The results and discussion in this paper revealed the “structural influence” crucial for the full and dynamical understanding of nZVI reactions. PMID:26355955

Structural Evolution of Nanoscale Zero-Valent Iron (nZVI) in Anoxic Co(2+) Solution: Interactional Performance and Mechanism.

PubMed

Zhang, Yalei; Chen, Wen; Dai, Chaomeng; Zhou, Chuanlong; Zhou, Xuefei

2015-09-10

The structures of nanoscale zero-valent iron (nZVI) particles evolving during reactions, and the reactions are influenced by the evolved structures. To understand the removal process in detail, it is important to investigate the relationships between the reactions and structural evolution. Using high resolution-transmission electron microscopy (HR-TEM), typical evolved structures (sheet coprecipitation and cavity corrosion) of nZVI in anoxic Co(2+) solutions were revealed. The system pH (pH measured in mixture), which controls the stability of coprecipitation and the nZVI corrosion rate, were found to be the determining factors of structural evolutions. X-ray photoelectron spectroscopy (XPS) results indicated that the formation and dissolution of sheet structure impacts on the ratio of Fe(0) on the nZVI surface and the surface Co(2+) reduction. The cavity structure provides the possibility of Co migration from the surface to the bulk of nZVI, leading to continuous removal. Subacidity conditions could accelerate the evolution and improve the removal; the results of structurally controlled reactions further indicated that the removal was suspended by the sheet structure and enhanced by cavity structure. The results and discussion in this paper revealed the "structural influence" crucial for the full and dynamical understanding of nZVI reactions.

Structural Evolution of Nanoscale Zero-Valent Iron (nZVI) in Anoxic Co2+ Solution: Interactional Performance and Mechanism

NASA Astrophysics Data System (ADS)

Zhang, Yalei; Chen, Wen; Dai, Chaomeng; Zhou, Chuanlong; Zhou, Xuefei

2015-09-01

The structures of nanoscale zero-valent iron (nZVI) particles evolving during reactions, and the reactions are influenced by the evolved structures. To understand the removal process in detail, it is important to investigate the relationships between the reactions and structural evolution. Using high resolution-transmission electron microscopy (HR-TEM), typical evolved structures (sheet coprecipitation and cavity corrosion) of nZVI in anoxic Co2+ solutions were revealed. The system pH (pH measured in mixture), which controls the stability of coprecipitation and the nZVI corrosion rate, were found to be the determining factors of structural evolutions. X-ray photoelectron spectroscopy (XPS) results indicated that the formation and dissolution of sheet structure impacts on the ratio of Fe(0) on the nZVI surface and the surface Co2+ reduction. The cavity structure provides the possibility of Co migration from the surface to the bulk of nZVI, leading to continuous removal. Subacidity conditions could accelerate the evolution and improve the removal; the results of structurally controlled reactions further indicated that the removal was suspended by the sheet structure and enhanced by cavity structure. The results and discussion in this paper revealed the “structural influence” crucial for the full and dynamical understanding of nZVI reactions.

Electrostatic roles in electron transfer from [NiFe] hydrogenase to cytochrome c3 from Desulfovibrio vulgaris Miyazaki F.

PubMed

Sugimoto, Yu; Kitazumi, Yuki; Shirai, Osamu; Nishikawa, Koji; Higuchi, Yoshiki; Yamamoto, Masahiro; Kano, Kenji

2017-05-01

Electrostatic interactions between proteins are key factors that govern the association and reaction rate. We spectroscopically determine the second-order reaction rate constant (k) of electron transfer from [NiFe] hydrogenase (H 2 ase) to cytochrome (cyt) c 3 at various ionic strengths (I). The k value decreases with I. To analyze the results, we develop a semi-analytical formula for I dependence of k based on the assumptions that molecules are spherical and the reaction proceeds via a transition state. Fitting of the formula to the experimental data reveals that the interaction occurs in limited regions with opposite charges and with radii much smaller than those estimated from crystal structures. This suggests that local charges in H 2 ase and cyt c 3 play important roles in the reaction. Although the crystallographic data indicate a positive electrostatic potential over almost the entire surface of the proteins, there exists a small region with negative potential on H 2 ase at which the electron transfer from H 2 ase to cyt c 3 may occur. This local negative potential region is identical to the hypothetical interaction sphere predicted by the analysis. Furthermore, I dependence of k is predicted by the Adaptive Poisson-Boltzmann Solver considering all charges of the amino acids in the proteins and the configuration of H 2 ase/cyt c 3 complex. The calculation reproduces the experimental results except at extremely low I. These results indicate that the stabilization derived from the local electrostatic interaction in the H 2 ase/cyt c 3 complex overcomes the destabilization derived from the electrostatic repulsion of the overall positive charge of both proteins. Copyright © 2017 Elsevier B.V. All rights reserved.

Origin of the SN2 benzylic effect.

PubMed

Galabov, Boris; Nikolova, Valia; Wilke, Jeremiah J; Schaefer, Henry F; Allen, Wesley D

2008-07-30

The S N2 identity exchange reactions of the fluoride ion with benzyl fluoride and 10 para-substituted derivatives (RC6H 4CH 2F, R = CH3, OH, OCH 3, NH2, F, Cl, CCH, CN, COF, and NO2) have been investigated by both rigorous ab initio methods and carefully calibrated density functional theory. Groundbreaking focal-point computations were executed for the C6H5CH 2F + F (-) and C 6H 5CH2Cl + Cl (-) SN2 reactions at the highest possible levels of electronic structure theory, employing complete basis set (CBS) extrapolations of aug-cc-pV XZ (X = 2-5) Hartree-Fock and MP2 energies, and including higher-order electron correlation via CCSD/aug-cc-pVQZ and CCSD(T)/aug-cc-pVTZ coupled cluster wave functions. Strong linear dependences are found between the computed electrostatic potential at the reaction-center carbon atom and the effective SN2 activation energies within the series of para-substituted benzyl fluorides. An activation strain energy decomposition indicates that the SN2 reactivity of these benzylic compounds is governed by the intrinsic electrostatic interaction between the reacting fragments. The delocalization of nucleophilic charge into the aromatic ring in the SN2 transition states is quite limited and should not be considered the origin of benzylic acceleration of SN2 reactions. Our rigorous focal-point computations validate the benzylic effect by establishing SN2 barriers for (F (-), Cl (-)) identity exchange in (C6H5CH2F, C6H 5CH2Cl) that are lower than those of (CH3F, CH3Cl) by (3.8, 1.6) kcal mol (-1), in order.

Hospital networks: how to make them work in Belgium? Facilitators and barriers of different governance models.

PubMed

De Pourcq, Kaat; De Regge, Melissa; Van den Heede, Koen; Van de Voorde, Carine; Gemmel, Paul; Eeckloo, Kristof

2018-03-29

Objectives This study aims to identify the facilitators and barriers to governance models of hospital collaborations. The country-specific characteristics of the Belgian healthcare system and legislation are taken into account. Methods A case study was carried out in six Belgian hospital collaborations. Different types of governance models were selected: two health systems, two participant-governed networks, and two lead-organization-governed networks. Within these collaborations, 43 people were interviewed. Results All structures have both advantages and disadvantages. It is important that the governance model fits the network. However, structural, procedural, and especially contextual factors also affect the collaborations, such as alignment of hospitals' and professionals' goals, competition, distance, level of integrated care, time needed for decision-making, and legal and financial incentives. Conclusion The fit between the governance model and the collaboration can facilitate the functioning of a collaboration. The main barriers we identified are contextual factors. The Belgian government needs to play a major role in facilitating collaboration.

Implementation of clinical governance in hospitals: challenges and the keys for success.

PubMed

Mousavi, Seyed Mohammad Hadi; Agharahimi, Zahra; Daryabeigi, Maede; Rezaei, Nima

2014-01-01

There is a number of models and strategies for improving the quality of care such as total quality management, continuous quality improvement and clinical governance. The policy of clinical governance is part of the governments overall strategy for monitoring, assuring and improving in the national health services organization. Clinical governance has been introduced as a bridge between managerial and clinical approaches to quality. For successful implementing of clinical governance, it is necessary to pay attention to firm foundations of the structure, including equipment, staffing arrangement, supporting specialties, and staff training. Therefore, as clinical governance improves safety and quality in health care services, the current situation in hospitals should be evaluated before any intervention while barriers and blocks on structure and process should be determined to select a method for changing them. Considering these points could guarantee success in implementation of clinical governance; otherwise there would be a little chance to achieve the desired results despite consumption of plenty of time and huge paper works.

75 FR 30453 - Self-Regulatory Organizations; Financial Industry Regulatory Authority, Inc.; Order Approving...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-06-01

... closely the governance structure of the FINRA Board. Section 4.3--Qualifications The proposed rule change would amend Article IV, section 4.3(a) to reflect FINRA's current governance structure by establishing... to Article IV, section 4.3 as follows: Re-structure the Board to remove the President of NASD Dispute...

Afghanistan: Post-Taliban Governance, Security, and U.S. Policy

DTIC Science & Technology

2016-06-06

9 U.S. and International Civilian Policy Structure ...Afghanistan. However, some warned that a post-Soviet power structure in Afghanistan could be adverse to U.S. interests because much of the covert aid was...appointments, priorities, the future of the governing structure , and Ghani’s outreach to Pakistan—to the point where some senior officials have resigned

Assessing the Role and Structure of Academic Senates in Canadian Universities, 2000-2012

ERIC Educational Resources Information Center

Pennock, Lea; Jones, Glen A.; Leclerc, Jeff M.; Li, Sharon X.

2015-01-01

Academic governance is an important dimension of institutional self-governance. This paper reports on the findings of a new study of university senates (academic councils) in Canadian universities in order to analyze changes in structure and in senate members' perceptions of the structure and role of senates over the last decade. Following the…

The Impact of Governance on the Performance of the Higher Education Sector in Australia

ERIC Educational Resources Information Center

De Silva Lokuwaduge, Chitra; Armstrong, Anona

2015-01-01

Australian government concern for improved governance in the higher education sector over recent years has driven the implementation of governance protocols. However, there has been little evidence of any evaluation of the impact of the governance structures on the performance of universities. This paper presents an analysis of the impact of the…

School Board Governance in Changing Times: A School's Transition to Policy Governance

ERIC Educational Resources Information Center

Curry, Katherine; Kinder, Sean; Benoiton, Tania; Noonan, Jessica

2018-01-01

The expansion of the school choice movement and greater flexibility allowed by Every Student Succeeds Act (ESSA) means that education governance is emerging as an important issue for school effectiveness. This longitudinal case study sought to gain an understanding of the implementation of a new governance structure, Policy Governance, in a…

Anti-Stokes resonant x-ray Raman scattering for atom specific and excited state selective dynamics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kunnus, Kristjan; Josefsson, Ida; Rajkovic, Ivan

Here, ultrafast electronic and structural dynamics of matter govern rate and selectivity of chemical reactions, as well as phase transitions and efficient switching in functional materials. Since x-rays determine electronic and structural properties with elemental, chemical, orbital and magnetic selectivity, short pulse x-ray sources have become central enablers of ultrafast science. Despite of these strengths, ultrafast x-rays have been poor at picking up excited state moieties from the unexcited ones. With time-resolved anti-Stokes resonant x-ray Raman scattering (AS-RXRS) performed at the LCLS, and ab initio theory we establish background free excited state selectivity in addition to the elemental, chemical, orbitalmore » and magnetic selectivity of x-rays. This unparalleled selectivity extracts low concentration excited state species along the pathway of photo induced ligand exchange of Fe(CO)5 in ethanol. Conceptually a full theoretical treatment of all accessible insights to excited state dynamics with AS-RXRS with transform-limited x-ray pulses is given—which will be covered experimentally by upcoming transform-limited x-ray sources.« less

Theoretical aspects of tidal and planetary wave propagation at thermospheric heights

NASA Technical Reports Server (NTRS)

Volland, H.; Mayr, H. G.

1977-01-01

A simple semiquantitative model is presented which allows analytic solutions of tidal and planetary wave propagation at thermospheric heights. This model is based on perturbation approximation and mode separation. The effects of viscosity and heat conduction are parameterized by Rayleigh friction and Newtonian cooling. Because of this simplicity, one gains a clear physical insight into basic features of atmospheric wave propagation. In particular, we discuss the meridional structures of pressure and horizontal wind (the solutions of Laplace's equation) and their modification due to dissipative effects at thermospheric heights. Furthermore, we solve the equations governing the height structure of the wave modes and arrive at a very simple asymptotic solution valid in the upper part of the thermosphere. That 'system transfer function' of the thermosphere allows one to estimate immediately the reaction of the thermospheric wave mode parameters such as pressure, temperature, and winds to an external heat source of arbitrary temporal and spatial distribution. Finally, the diffusion effects of the minor constituents due to the global wind circulation are discussed, and some results of numerical calculations are presented.

Glycolysis Is Governed by Growth Regime and Simple Enzyme Regulation in Adherent MDCK Cells

PubMed Central

Rehberg, Markus; Ritter, Joachim B.; Reichl, Udo

2014-01-01

Due to its vital importance in the supply of cellular pathways with energy and precursors, glycolysis has been studied for several decades regarding its capacity and regulation. For a systems-level understanding of the Madin-Darby canine kidney (MDCK) cell metabolism, we couple a segregated cell growth model published earlier with a structured model of glycolysis, which is based on relatively simple kinetics for enzymatic reactions of glycolysis, to explain the pathway dynamics under various cultivation conditions. The structured model takes into account in vitro enzyme activities, and links glycolysis with pentose phosphate pathway and glycogenesis. Using a single parameterization, metabolite pool dynamics during cell cultivation, glucose limitation and glucose pulse experiments can be consistently reproduced by considering the cultivation history of the cells. Growth phase-dependent glucose uptake together with cell-specific volume changes generate high intracellular metabolite pools and flux rates to satisfy the cellular demand during growth. Under glucose limitation, the coordinated control of glycolytic enzymes re-adjusts the glycolytic flux to prevent the depletion of glycolytic intermediates. Finally, the model's predictive power supports the design of more efficient bioprocesses. PMID:25329309

Glycolysis is governed by growth regime and simple enzyme regulation in adherent MDCK cells.

PubMed

Rehberg, Markus; Ritter, Joachim B; Reichl, Udo

2014-10-01

Due to its vital importance in the supply of cellular pathways with energy and precursors, glycolysis has been studied for several decades regarding its capacity and regulation. For a systems-level understanding of the Madin-Darby canine kidney (MDCK) cell metabolism, we couple a segregated cell growth model published earlier with a structured model of glycolysis, which is based on relatively simple kinetics for enzymatic reactions of glycolysis, to explain the pathway dynamics under various cultivation conditions. The structured model takes into account in vitro enzyme activities, and links glycolysis with pentose phosphate pathway and glycogenesis. Using a single parameterization, metabolite pool dynamics during cell cultivation, glucose limitation and glucose pulse experiments can be consistently reproduced by considering the cultivation history of the cells. Growth phase-dependent glucose uptake together with cell-specific volume changes generate high intracellular metabolite pools and flux rates to satisfy the cellular demand during growth. Under glucose limitation, the coordinated control of glycolytic enzymes re-adjusts the glycolytic flux to prevent the depletion of glycolytic intermediates. Finally, the model's predictive power supports the design of more efficient bioprocesses.

Anti-Stokes resonant x-ray Raman scattering for atom specific and excited state selective dynamics

DOE PAGES

Kunnus, Kristjan; Josefsson, Ida; Rajkovic, Ivan; ...

2016-10-07

Here, ultrafast electronic and structural dynamics of matter govern rate and selectivity of chemical reactions, as well as phase transitions and efficient switching in functional materials. Since x-rays determine electronic and structural properties with elemental, chemical, orbital and magnetic selectivity, short pulse x-ray sources have become central enablers of ultrafast science. Despite of these strengths, ultrafast x-rays have been poor at picking up excited state moieties from the unexcited ones. With time-resolved anti-Stokes resonant x-ray Raman scattering (AS-RXRS) performed at the LCLS, and ab initio theory we establish background free excited state selectivity in addition to the elemental, chemical, orbitalmore » and magnetic selectivity of x-rays. This unparalleled selectivity extracts low concentration excited state species along the pathway of photo induced ligand exchange of Fe(CO)5 in ethanol. Conceptually a full theoretical treatment of all accessible insights to excited state dynamics with AS-RXRS with transform-limited x-ray pulses is given—which will be covered experimentally by upcoming transform-limited x-ray sources.« less

Topotactic Metal-Insulator Transition in Epitaxial SrFeO x Thin Films

DOE PAGES

Khare, Amit; Shin, Dongwon; Yoo, Tae Sup; ...

2017-07-31

Multivalent transition metal oxides provide fascinating and rich physics related to oxygen stoichiometry. In particular, the adoptability of various valence states of transition metals enables perovskite oxides to display mixed (oxygen) ionic and electronic conduction and catalytic activity useful in many practical applications, including solid-oxide fuel cells (SOFCs), rechargeable batteries, gas sensors, and memristive devices. For proper realization of the ionic conduction and catalytic activity, it is essential to understand the reversible oxidation and reduction process, which is governed by oxygen storage/release steps in oxides. Topotactic phase transformation facilitates the redox process in perovskites with specific oxygen vacancy ordering bymore » largely varying the oxygen concentration of a material without losing the lattice framework. The concentration and diffusion of oxide ions (O 2–), the valence state of the transition metal cations, and the thermodynamic structural integrity together provide fundamental understanding and ways to explicitly control the redox reaction.[6] In addition, it offers an attractive route for tuning the emergent physical properties of transition metal oxides, via strong coupling between the crystal lattice and electronic structure.« less

Research-based planning for change: assessing nurses' attitudes toward governance and professional practice autonomy after hospital acquisition.

PubMed

George, V M; Burke, L J; Rodgers, B L

1997-05-01

This article describes one medical center's experience in using research to plan for nursing staff integration after hospital acquisition. Resistance to new policies, procedures, and standards; passive acceptance of new leadership; limited support for management plans; and failure to integrate with new nursing units are common staff reactions after acquisitions. Little has been written regarding which key staff variables to assess after acquisitions and how to use this data to plan for change. Structural contingency and attribution theory were used to guide leadership staff's assessment of acquired staff attributes to determine their congruence with concepts valued by the acquiring organization. Qualitative and quantitative data were collected using a survey method. All 141 registered nurses and licensed practical nurses of the acquired medical center received a mailed survey. Sixty-six completed surveys were returned through the U.S. mail. No identifying information was placed on the survey to assure anonymity. The survey results described nurses perceptions of the advantages, concerns, and suggestions for a smooth transition after acquisition. In addition, the results clarified that nurses in the newly acquired hospital preferred a shared governance structure (congruent with the acquiring medical center's values) and the nurses perceived professional nursing autonomy was similar to that of nurses who worked at the acquiring medical center. By sharing the findings, both staffs were sensitized to the similarities among the staff as well as to their differences. Transition strategies were planned to capitalize on this knowledge. This process may be useful for other nurse executives to replicate as they guide their organizations through similar transitions.

Synthesis and Structural Studies of Calcium and Magnesium Phosphinate and Phosphonate Compounds

NASA Astrophysics Data System (ADS)

Bampoh, Victoria Naa Kwale

The work presented herein describes synthetic methodologies leading to the design of a wide array of magnesium and calcium based phosphinate and phosphonates with possible applications as bone scaffolding materials or additives to bone cements. The challenge to the chemistry of the alkaline earth phosphonate target compounds includes poor solubility of compounds, and poorly understood details on the control of the metal's coordination environment. Hence, less is known on phosphonate based alkaline earth metal organic frameworks as compared to transition metal phosphonates. Factors governing the challenges in obtaining crystalline, well-defined magnesium and calcium solids lie in the large metal diameters, the absence of energetically available d-orbitals to direct metal geometry, as well as the overall weakness of the metal-ligand bonds. A significant part of this project was concerned with the development of suitable reaction conditions to obtain X-ray quality crystals of the reaction products to allow for structural elucidation of the novel compounds. Various methodologies to aid in crystal growth including hydrothermal methods and gel crystallization were employed. We have used phosphinate and phosphonate ligands with different number of phosphorus oxygen atoms as well as diphosphonates with different linker lengths to determine their effects on the overall structural features. An interesting correlation is observed between the dimensionality of products and the increasing number of donor oxygen atoms in the ligands as we progress from phosphinic acid to the phosphorous acids. As an example, monophosphinate ligand only yielded one-dimensional compounds, whereas the phosphonates crystallize as one and two-dimensional compounds, and the di- and triphosphonate based compounds display two or three-dimensional geometries. This thesis provides a selection of calcium and magnesium compounds with one-dimensional geometry, as represented in a calcium phosphinate to novel two-dimensional sheets of magnesium and pillared calcium phosphonates. The preparation of these novel compounds has led to the establishment of synthetic protocols that allow for the direct preparation of compounds with defined structural features.

Structural Models that Manage IT Portfolio Affecting Business Value of Enterprise Architecture

NASA Astrophysics Data System (ADS)

Kamogawa, Takaaki

This paper examines the structural relationships between Information Technology (IT) governance and Enterprise Architecture (EA), with the objective of enhancing business value in the enterprise society. Structural models consisting of four related hypotheses reveal the relationship between IT governance and EA in the improvement of business values. We statistically examined the hypotheses by analyzing validated questionnaire items from respondents within firms listed on the Japanese stock exchange who were qualified to answer them. We concluded that firms which have organizational ability controlled by IT governance are more likely to deliver business value based on IT portfolio management.

Systems and processes that ensure high quality care.

PubMed

Bassett, Sally; Westmore, Kathryn

2012-10-01

This is the second in a series of articles examining the components of good corporate governance. It considers how the structures and processes for quality governance can affect an organisation's ability to be assured about the quality of care. Complex information systems and procedures can lead to poor quality care, but sound structures and processes alone are insufficient to ensure good governance, and behavioural factors play a significant part in making sure that staff are enabled to provide good quality care. The next article in this series looks at how the information reporting of an organisation can affect its governance.

A Model for Determining Optimal Governance Structure in DoD Acquisition Projects in a Performance-Based Environment

DTIC Science & Technology

2010-04-30

combating market dynamism (Aldrich, 1979; Child, 1972), which is a result of evolving technology, shifting prices, or variance in product availability... principles : (1) human beings are bounded rationally, and (2), as a result of being rationally bound, will always choose to further their own self... principles to govern the relationship among the buyers and suppliers. Our conceptual model aligns the alternative governance structures derived

Explaining reaction mechanisms using the dual descriptor: a complementary tool to the molecular electrostatic potential.

PubMed

Martínez-Araya, Jorge Ignacio

2013-07-01

The intrinsic reactivity of cyanide when interacting with a silver cation was rationalized using the dual descriptor (DD) as a complement to the molecular electrostatic potential (MEP) in order to predict interactions at the local level. It was found that DD accurately explains covalent interactions that cannot be explained by MEP, which focuses on essentially ionic interactions. This allowed the rationalization of the reaction mechanism that yields silver cyanide in the gas phase. Other similar reaction mechanisms involving a silver cation interacting with water, ammonia, and thiosulfate were also explained by the combination of MEP and DD. This analysis provides another example of the usefulness of DD as a tool for gaining a deeper understanding of any reaction mechanism that is mainly governed by covalent interactions.

3D DNS of Turbulent Premixed Flame with over 50 Species and 300 Elementary Reactions

NASA Astrophysics Data System (ADS)

Shimura, Masayasu; Yenerdag, Basmil; Naka, Yoshitsugu; Nada, Yuzuru; Tanahashi, Mamoru

2014-11-01

Three-dimensional direct numerical simulation of methane-air premixed planar flame propagating in homogenous isotropic turbulence is conducted to investigate local flame structure in thin reaction zones. Detailed kinetic mechanism, GRI-Mech 3.0 which includes 53 species and 325 elementary reactions, is used to represent methane-air reaction, and temperature dependences of transport and thermal properties are considered. For a better understanding of the local flame structure in thin reaction zones regime, distributions of mass fractions of major species, heat release rate, temperature and turbulent structures are investigated. Characteristic flame structures, such as radical fingering and multi-layered-like flame structures, are observed. The most expected maximum heat release rate in flame elements is lower than that of laminar flame with same mixture. To clarify mechanism of the decrease in local heat release rate, effects of strain rates tangential to flame front on local heat release rate are investigated.

Complex governance structures and incoherent policies: Implementing the EU water framework directive in Sweden.

PubMed

Söderberg, Charlotta

2016-12-01

Contemporary processes of environmental policymaking in general span over several territorial tiers. This also holds for the EU Water Framework Directive system of environmental quality standards (EQS), which are part of a complex multi-level institutional landscape, embracing both EU, national and sub-national level. Recent evaluations show that many EU member states, including Sweden, have not reached the ecological goals for water in 2015. Departing from theories on policy coherence and multi-level governance, this paper therefore analyses Swedish water governance as a case to further our understanding of policy implementation in complex governance structures: how does policy coherence (or the lack thereof) affect policy implementation in complex governance structures? To answer this question, the paper maps out the formal structure of the water governance system, focusing on power directions within the system, analyses policy coherence in Swedish water governance through mapping out policy conflicts between the EQS for water and other goals/regulations and explore how they are handled by national and sub-national water bureaucrats. The study concludes that without clear central guidance, 'good ecological status' for Swedish water will be difficult to achieve since incoherent policies makes policy implementation inefficient due to constant power struggles between different authorities, and since environmental goals are often overridden by economic and other societal goals. Further research is needed in order to explore if similar policy conflicts between water quality and other objectives occur in other EU member states and how bureaucrats handle such conflicts in different institutional settings. This study of the Swedish case indicates that the role of the state as a navigator and rudder-holder is important in order to improve policy implementation in complex governance structures - otherwise; bureaucrats risk being lost in an incoherent archipelago of ecological, social and economic goals. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Grignard Reagent: Preparation, Structure, and Some Reactions.

ERIC Educational Resources Information Center

Orchin, Milton

1989-01-01

The Grignard reagent used in the laboratory synthesis of organic compounds is the product resulting from the reaction of an alkyl or aryl halide with elemental magnesium. Describes the structure, formation, and some reactions of the reagent. (YP)

Trends in Canadian School Finance.

ERIC Educational Resources Information Center

Atherton, Peter J.

The great similarity between the Canadian and American structures of school finance conceals some fundamental, constitutional, and structural differences that shape the trends in Canadian school finance. First, provincial governments exercise a high degree of centralized control over education and its finance. Second, provincial governments have…

TRACE ELEMENT CHEMISTRY IN RESIDUAL-TREATED SOIL: KEY CONCEPTS AND METAL BIOAVAILABILITY

EPA Science Inventory

Trace element solubility and availability in land-applied residuals is governed by fundamental chemical reactions between metal constituents, soil, and residual components. Iron, aluminum, and manganese oxides; organic matter; and phosphates, carbonates, and sulfides are importan...

Are Public-Private Partnerships an Appropriate Governance Structure for Power Plants? A Transaction Cost Analysis

NASA Astrophysics Data System (ADS)

Ho, S. Ping; Hsu, Yaowen

2015-04-01

In order to meet the requirements of the rapid economic growth, many countries demand an increasing number of power plants to meet the increasing electricity usage. Since high capital requirements of power plants present a big issue for these countries, PPPs have been considered an alternative to provide power plant infrastructure. In particular, in emerging or developing countries, PPPs may be the fastest way to provide the infrastructure needed. However, while PPPs are a promising alternative to providing various types of infrastructure, many failed power plant PPP projects have made it evident that PPPs, under certain situations, can be very costly or even a wrong choice of governance structure. While the higher efficiency due to better pooling of resources is greatly emphasized in Public-Private Partnerships (PPPs), the embedded transaction inefficiencies are often understated or even ignored. Through the lens of Transaction Cost Economics (TCE), this paper aims to answer why and when PPPs may become a costly governance structure for power plants. Specifically, we develop a TCE-based theory of PPPs as a governance structure. This theory suggests that three major opportunism problems embedded in infrastructure PPPs are possible to cause substantial transaction costs and render PPPs a costly governance structure. The three main opportunism problems are principal-principal problem, firm's hold-up problem, and government-led hold-up problem. Moreover, project and institutional characteristics that may lead to opportunism problems are identified. Based on these characteristics, an opportunism-focused transaction cost analysis (OTCA) for PPPs as a governance structure is proposed to supplement the current practice of PPP feasibility analysis. As a part of theory development, a case study of PPP power plants is performed to evaluate the proposed theory and to illustrate how the proposed OTCA can be applied in practice. Policies and administration strategies for power plant PPPs are derived based on the proposed theory.

The Taiwan Tobacco and Liquor Corporation: To ‘join the ranks of global companies’

PubMed Central

Eckhardt, Jappe; Fang, Jennifer; Lee, Kelley

2017-01-01

ABSTRACT Until the late 1990s, the Taiwan Tobacco and Liquor Corporation (TTL) focused almost exclusively on serving the domestic market as a highly protected monopoly. This paper describes how the company has adopted a more outward looking strategy since 2000, with ambitions to become a regional, and eventually global, business by 2021. Drawing on company documents and industry sources, the paper argues that this shift in strategy was a direct reaction to the decline in domestic market share following liberalisation of the Taiwanese tobacco market and adoption of tougher domestic tobacco control measures. Market opening occurred as a result of pressure from the U.S. Trade Representative in the 1980s, as well as World Trade Organization membership in 2002. It is argued that TTL’s efforts to globalise operations have been limited by bureaucratic company management and structures, and ongoing political tension between Taiwan and China. However, the relative success of TTL’s alcohol branch, and potential détente as the Taiwanese government reaches out to improve relations with China, may provide TTL with new opportunities to achieve its goal of becoming a regional player with global ambitions. This article is part of the special issue ‘The Emergence of Asian Tobacco Companies: Implications for Global Health Governance.’ PMID:28139964

The Taiwan Tobacco and Liquor Corporation: To 'join the ranks of global companies'.

PubMed

Eckhardt, Jappe; Fang, Jennifer; Lee, Kelley

2017-03-01

Until the late 1990s, the Taiwan Tobacco and Liquor Corporation (TTL) focused almost exclusively on serving the domestic market as a highly protected monopoly. This paper describes how the company has adopted a more outward looking strategy since 2000, with ambitions to become a regional, and eventually global, business by 2021. Drawing on company documents and industry sources, the paper argues that this shift in strategy was a direct reaction to the decline in domestic market share following liberalisation of the Taiwanese tobacco market and adoption of tougher domestic tobacco control measures. Market opening occurred as a result of pressure from the U.S. Trade Representative in the 1980s, as well as World Trade Organization membership in 2002. It is argued that TTL's efforts to globalise operations have been limited by bureaucratic company management and structures, and ongoing political tension between Taiwan and China. However, the relative success of TTL's alcohol branch, and potential détente as the Taiwanese government reaches out to improve relations with China, may provide TTL with new opportunities to achieve its goal of becoming a regional player with global ambitions. This article is part of the special issue 'The Emergence of Asian Tobacco Companies: Implications for Global Health Governance.'

X-34 Main Propulsion System Design and Operation

NASA Technical Reports Server (NTRS)

Champion, R. J., Jr.; Darrow, R. J., Jr.

1998-01-01

The X-34 program is a joint industry/government program to develop, test, and operate a small, fully-reusable hypersonic flight vehicle, utilizing technologies and operating concepts applicable to future Reusable Launch Vehicle (RLV) systems. The vehicle will be capable of Mach 8 flight to 250,000 feet altitude and will demonstrate an all composite structure, composite RP-1 tank, the Marshall Space Flight Center (MSFC) developed Fastrac engine, and the operability of an advanced thermal protection systems. The vehicle will also be capable of carrying flight experiments. MSFC is supporting the X-34 program in three ways: Program Management, the Fastrac engine as Government Furnished Equipment (GFE), and the design of the Main Propulsion System (MPS). The MPS Product Development Team (PDT) at MSFC is responsible for supplying the MPS design, analysis, and drawings to Orbital. The MPS consists of the LOX and RP-1 Fill, Drain, Feed, Vent, & Dump systems and the Helium & Nitrogen Purge, Pressurization, and Pneumatics systems. The Reaction Control System (RCS) design was done by Orbital. Orbital is the prime contractor and has responsibility for integration, procurement, and construction of all subsystems. The paper also discusses the design, operation, management, requirements, trades studies, schedule, and lessons learning with the MPS and RCS designs.

The Governance of Public Libraries: Findings of the PLA Governance of Public Libraries Committee.

ERIC Educational Resources Information Center

Scheppke, Jim

1991-01-01

Describes a survey of library development officers in state library agencies that was conducted to investigate the types of governance structures of public libraries. Highlights include consolidation of public library services, public library boards, trends in public library governance, financial support and managerial effectiveness, and…

45 CFR 1304.50 - Program governance.

Code of Federal Regulations, 2010 CFR

2010-10-01

... 45 Public Welfare 4 2010-10-01 2010-10-01 false Program governance. 1304.50 Section 1304.50 Public... AGENCIES Program Design and Management § 1304.50 Program governance. (a) Policy Council, Policy Committee... structure of shared governance through which parents can participate in policy making or in other decisions...

45 CFR 1304.50 - Program governance.

Code of Federal Regulations, 2011 CFR

2011-10-01

... 45 Public Welfare 4 2011-10-01 2011-10-01 false Program governance. 1304.50 Section 1304.50 Public... AGENCIES Program Design and Management § 1304.50 Program governance. (a) Policy Council, Policy Committee... structure of shared governance through which parents can participate in policy making or in other decisions...

18 CFR 11.2 - Use of government lands.

Code of Federal Regulations, 2013 CFR

2013-04-01

... Government dams or other structures owned by the United States Government) or its other property, will be... 18 Conservation of Power and Water Resources 1 2013-04-01 2013-04-01 false Use of government lands. 11.2 Section 11.2 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION...

18 CFR 11.2 - Use of government lands.

Code of Federal Regulations, 2014 CFR

2014-04-01

... Government dams or other structures owned by the United States Government) or its other property, will be... 18 Conservation of Power and Water Resources 1 2014-04-01 2014-04-01 false Use of government lands. 11.2 Section 11.2 Conservation of Power and Water Resources FEDERAL ENERGY REGULATORY COMMISSION...

Harbingers of the Caliphate: Islamic State Revolutionary Actions 2011-2014

DTIC Science & Technology

2016-06-01

movements and tribal organizations. This evaluation illuminates the Islamic State’s internal structure and methodology for governing territory to support...and tribal organizations. This evaluation illuminates the Islamic State’s internal structure and methodology for governing territory to support...schools of thought: Theories that recognize structural conditions as the seminal factor leading to revolution, and those that recognize actors and

Sparse Regression Based Structure Learning of Stochastic Reaction Networks from Single Cell Snapshot Time Series.

PubMed

Klimovskaia, Anna; Ganscha, Stefan; Claassen, Manfred

2016-12-01

Stochastic chemical reaction networks constitute a model class to quantitatively describe dynamics and cell-to-cell variability in biological systems. The topology of these networks typically is only partially characterized due to experimental limitations. Current approaches for refining network topology are based on the explicit enumeration of alternative topologies and are therefore restricted to small problem instances with almost complete knowledge. We propose the reactionet lasso, a computational procedure that derives a stepwise sparse regression approach on the basis of the Chemical Master Equation, enabling large-scale structure learning for reaction networks by implicitly accounting for billions of topology variants. We have assessed the structure learning capabilities of the reactionet lasso on synthetic data for the complete TRAIL induced apoptosis signaling cascade comprising 70 reactions. We find that the reactionet lasso is able to efficiently recover the structure of these reaction systems, ab initio, with high sensitivity and specificity. With only < 1% false discoveries, the reactionet lasso is able to recover 45% of all true reactions ab initio among > 6000 possible reactions and over 102000 network topologies. In conjunction with information rich single cell technologies such as single cell RNA sequencing or mass cytometry, the reactionet lasso will enable large-scale structure learning, particularly in areas with partial network structure knowledge, such as cancer biology, and thereby enable the detection of pathological alterations of reaction networks. We provide software to allow for wide applicability of the reactionet lasso.

Analysis of Three-Dimensional, Nonlinear Development of Wave-Like Structure in a Compressible Round Jet

NASA Technical Reports Server (NTRS)

Dahl, Milo D.; Mankbadi, Reda R.

2002-01-01

An analysis of the nonlinear development of the large-scale structures or instability waves in compressible round jets was conducted using the integral energy method. The equations of motion were decomposed into two sets of equations; one set governing the mean flow motion and the other set governing the large-scale structure motion. The equations in each set were then combined to derive kinetic energy equations that were integrated in the radial direction across the jet after the boundary-layer approximations were applied. Following the application of further assumptions regarding the radial shape of the mean flow and the large structures, equations were derived that govern the nonlinear, streamwise development of the large structures. Using numerically generated mean flows, calculations show the energy exchanges and the effects of the initial amplitude on the coherent structure development in the jet.

Synthesis of rhenium nitride crystals with MoS2 structure

NASA Astrophysics Data System (ADS)

Kawamura, Fumio; Yusa, Hitoshi; Taniguchi, Takashi

2012-06-01

Rhenium nitride (ReN2) crystals were synthesized from a metathesis reaction between ReCl5 and Li3N under high pressure. The reaction was well controlled by the addition of a large amount of NaCl as reaction inhibitor to prevent a violent exothermic reaction. The largest rhenium nitride crystals obtained had a millimeter-order size with a platelet shape. X-ray diffraction analysis revealed that rhenium nitride has MoS2 structure similar to hexagonal rhenium diboride (ReB2) which has recently been investigated as an ultra-hard material. The structure was different from any structures previously predicted for ReN2 by theoretical calculations.

Ignitable heterogeneous stratified structure for the propagation of an internal exothermic chemical reaction along an expanding wavefront and method of making same

DOEpatents

Barbee, T.W. Jr.; Weihs, T.

1996-07-23

A multilayer structure has a selectable, (1) propagating reaction front velocity V, (2) reaction initiation temperature attained by application of external energy, and (3) amount of energy delivered by a reaction of alternating unreacted layers of the multilayer structure. Because V is selectable and controllable, a variety of different applications for the multilayer structures are possible, including but not limited to their use as igniters, in joining applications, in fabrication of new materials, as smart materials and in medical applications and devices. The multilayer structure has a period D, and an energy release rate constant K. Two or more alternating unreacted layers are made of different materials and separated by reacted zones. The period D is equal to a sum of the widths of each single alternating reaction layer of a particular material, and also includes a sum of reacted zone widths, t{sub i}, in the period D. The multilayer structure has a selectable propagating reaction front velocity V, where V=K(1/D{sup n}){times}[1-(t{sub i}/D)] and n is about 0.8 to 1.2. 8 figs.

Ignitable heterogeneous stratified structure for the propagation of an internal exothermic chemical reaction along an expanding wavefront and method of making same

DOEpatents

Barbee, Jr., Troy W.; Weihs, Timothy

1996-01-01

A multilayer structure has a selectable, (i) propagating reaction front velocity V, (ii) reaction initiation temperature attained by application of external energy and (iii) amount of energy delivered by a reaction of alternating unreacted layers of the multilayer structure. Because V is selectable and controllable, a variety of different applications for the multilayer structures are possible, including but not limited to their use as ignitors, in joining applications, in fabrication of new materials, as smart materials and in medical applications and devices. The multilayer structure has a period D, and an energy release rate constant K. Two or more alternating unreacted layers are made of different materials and separated by reacted zones. The period D is equal to a sum of the widths of each single alternating reaction layer of a particular material, and also includes a sum of reacted zone widths, t.sub.i, in the period D. The multilayer structure has a selectable propagating reaction front velocity V, where V=K(1/D.sup.n).times.[1-(t.sub.i /D)] and n is about 0.8 to 1.2.

Hospital board structure: changing form and changing issues.

PubMed

Tregoning, S

2000-01-01

Economic and social pressures are compelling many hospitals to consider their current board structure in an effort to position their hospital to meet changing demands. A national profile of the structures of hospital boards has been compiled from a questionnaire completed by hospital board representatives from both government and non-government sectors. Results show that hospital board structures are a hybrid of both philanthropic and corporate models. New structures may be required to meet future challenges. In developing new structures, consideration should be given to identifying the skills and processes required to undertake board business.

Mental health network governance: comparative analysis across Canadian regions.

PubMed

Wiktorowicz, Mary E; Fleury, Marie-Josée; Adair, Carol E; Lesage, Alain; Goldner, Elliot; Peters, Suzanne

2010-10-26

Modes of governance were compared in ten local mental health networks in diverse contexts (rural/urban and regionalized/non-regionalized) to clarify the governance processes that foster inter-organizational collaboration and the conditions that support them. Case studies of ten local mental health networks were developed using qualitative methods of document review, semi-structured interviews and focus groups that incorporated provincial policy, network and organizational levels of analysis. Mental health networks adopted either a corporate structure, mutual adjustment or an alliance governance model. A corporate structure supported by regionalization offered the most direct means for local governance to attain inter-organizational collaboration. The likelihood that networks with an alliance model developed coordination processes depended on the presence of the following conditions: a moderate number of organizations, goal consensus and trust among the organizations, and network-level competencies. In the small and mid-sized urban networks where these conditions were met their alliance realized the inter-organizational collaboration sought. In the large urban and rural networks where these conditions were not met, externally brokered forms of network governance were required to support alliance based models. In metropolitan and rural networks with such shared forms of network governance as an alliance or voluntary mutual adjustment, external mediation by a regional or provincial authority was an important lever to foster inter-organizational collaboration.

Conservation of direct dynamics in sterically hindered SN2/E2 reactions.

PubMed

Carrascosa, Eduardo; Meyer, Jennifer; Michaelsen, Tim; Stei, Martin; Wester, Roland

2018-01-21

Nucleophilic substitution (S N 2) and base-induced elimination (E2), two indispensable reactions in organic synthesis, are commonly assumed to proceed under stereospecific conditions. Understanding the way in which the reactants pre-orient in these reactions, that is its stereodynamics, is essential in order to achieve a detailed atomistic picture and control over such processes. Using crossed beam velocity map imaging, we study the effect of steric hindrance in reactions of Cl - and CN - with increasingly methylated alkyl iodides by monitoring the product ion energy and scattering angle. For both attacking anions the rebound mechanism, indicative of a direct S N 2 pathway, is found to contribute to the reaction at high relative collision energies despite being increasingly hindered. An additional forward scattering mechanism, ascribed to a direct E2 reaction, also contributes at these energies. Inspection of the product energy distributions confirms the direct and fast character of both mechanisms as opposed to an indirect reaction mechanism which leads to statistical energy redistribution in the reaction complex. This work demonstrates that nonstatistical dynamics and energetics govern S N 2 and E2 pathways even in sterically hindered exchange reaction systems.

Conservation of direct dynamics in sterically hindered SN2/E2 reactions

PubMed Central

Carrascosa, Eduardo; Meyer, Jennifer; Michaelsen, Tim; Stei, Martin

2017-01-01

Nucleophilic substitution (SN2) and base-induced elimination (E2), two indispensable reactions in organic synthesis, are commonly assumed to proceed under stereospecific conditions. Understanding the way in which the reactants pre-orient in these reactions, that is its stereodynamics, is essential in order to achieve a detailed atomistic picture and control over such processes. Using crossed beam velocity map imaging, we study the effect of steric hindrance in reactions of Cl– and CN– with increasingly methylated alkyl iodides by monitoring the product ion energy and scattering angle. For both attacking anions the rebound mechanism, indicative of a direct SN2 pathway, is found to contribute to the reaction at high relative collision energies despite being increasingly hindered. An additional forward scattering mechanism, ascribed to a direct E2 reaction, also contributes at these energies. Inspection of the product energy distributions confirms the direct and fast character of both mechanisms as opposed to an indirect reaction mechanism which leads to statistical energy redistribution in the reaction complex. This work demonstrates that nonstatistical dynamics and energetics govern SN2 and E2 pathways even in sterically hindered exchange reaction systems. PMID:29629138

Governing boards and profound organizational change in hospitals.

PubMed

Fennell, M L; Alexander, J A

1989-01-01

Over the past decade the importance of governing boards as policy-making setting and oversight units within organizations has increased dramatically. Although this is true for both corporate- and private-sector organizations (Bacon and Brown 1977; Gelman 1988), it is particularly relevant to the health sector. Hospital governing boards, long considered inconsequential in hospital management, have recently become subject to closer scrutiny. The role of governing boards in decisions affecting hospital strategy and hospital performance is once again a topic of some interest in boardrooms and hospital trade journals. Impressive evidence of the renewed interest in governance is provided by the funding of an instructional consortium by the S.K. Kellogg Foundation to help strengthen trusteeship and governing board decision making, and to improve education for health services managers in the area of governance. Members of the consortium include the Hospital Research and Educational Trust, the American Hospital Association, the American College of Healthcare Executives, and the Association for University Programs in Health Administration. Among the activities being undertaken by this consortium is the development of a self-assessment tool/methodology for boards, a bibliography and reference guide on effective governance for practicing trustees, research workshops for faculty in health administration programs, and a teaching guide on governance and trustee leadership. Despite this interest, the question with which we began this article persists. Do governing boards make a difference? In the course of our review of previous work on governance we found that, more often than not, that question has been transformed into: how do boards influence hospital performance? And very often that question has been further narrowed into: which board structure leads to better hospital performance? We have argued for a respecification of the initial question. Rather than pursuing a definition of the maximally performing governing board, we should perhaps shift our focus back to a fuller understanding of board structure and function, and its influence on hospital change. The model developed here combines four essential, and very basic, questions: 1. What are the basic dimensions that underlie structural variation in different types of governing boards? 2. How do these board types influence structural change in hospitals? 3. How is the effect of board influence on change itself likely to change over time as a function of the hospital's general pattern of growth, decline, stability, or instability?(ABSTRACT TRUNCATED AT 400 WORDS)

Legal and Institutional Foundations of Adaptive Environmental Governance

EPA Science Inventory

Legal and institutional structures fundamentally shape opportunities for adaptive governance of environmental resources at multiple ecological and societal scales. Properties of adaptive governance are widely studied. However, these studies have not resulted in consolidated frame...

Reactivity index based on orbital energies.

PubMed

Tsuneda, Takao; Singh, Raman K

2014-05-30

This study shows that the chemical reactivities depend on the orbital energy gaps contributing to the reactions. In the process where a reaction only makes progress through charge transfer with the minimal structural transformation of the reactant, the orbital energy gap gradient (OEGG) between the electron-donating and electron-accepting orbitals is proven to be very low. Using this relation, a normalized reaction diagram is constructed by plotting the normalized orbital energy gap with respect to the normalized intrinsic reaction coordinate. Application of this reaction diagram to 43 fundamental reactions showed that the majority of the forward reactions provide small OEGGs in the initial stages, and therefore, the initial processes of the forward reactions are supposed to proceed only through charge transfer. Conversely, more than 60% of the backward reactions are found to give large OEGGs implying very slow reactions associated with considerable structural transformations. Focusing on the anti-activation-energy reactions, in which the forward reactions have higher barriers than those of the backward ones, most of these reactions are shown to give large OEGGs for the backward reactions. It is also found that the reactions providing large OEGGs in the forward directions inconsistent with the reaction rate constants are classified into SN 2, symmetric, and methyl radical reactions. Interestingly, several large-OEGG reactions are experimentally established to get around the optimum pathways. This indicates that the reactions can take significantly different pathways from the optimum ones provided no charge transfer proceeds spontaneously without the structural transformations of the reactants. Copyright © 2014 Wiley Periodicals, Inc.

Multi-path variational transition state theory for chemical reaction rates of complex polyatomic species: ethanol + OH reactions.

PubMed

Zheng, Jingjing; Truhlar, Donald G

2012-01-01

Complex molecules often have many structures (conformations) of the reactants and the transition states, and these structures may be connected by coupled-mode torsions and pseudorotations; some but not all structures may have hydrogen bonds in the transition state or reagents. A quantitative theory of the reaction rates of complex molecules must take account of these structures, their coupled-mode nature, their qualitatively different character, and the possibility of merging reaction paths at high temperature. We have recently developed a coupled-mode theory called multi-structural variational transition state theory (MS-VTST) and an extension, called multi-path variational transition state theory (MP-VTST), that includes a treatment of the differences in the multi-dimensional tunneling paths and their contributions to the reaction rate. The MP-VTST method was presented for unimolecular reactions in the original paper and has now been extended to bimolecular reactions. The MS-VTST and MP-VTST formulations of variational transition state theory include multi-faceted configuration-space dividing surfaces to define the variational transition state. They occupy an intermediate position between single-conformation variational transition state theory (VTST), which has been used successfully for small molecules, and ensemble-averaged variational transition state theory (EA-VTST), which has been used successfully for enzyme kinetics. The theories are illustrated and compared here by application to three thermal rate constants for reactions of ethanol with hydroxyl radical--reactions with 4, 6, and 14 saddle points.

cDNA encoding a polypeptide including a hevein sequence

DOEpatents

Raikhel, Natasha V.; Broekaert, Willem F.; Chua, Nam-Hai; Kush, Anil

1993-02-16

A cDNA clone (HEV1) encoding hevein was isolated via polymerase chain reaction (PCR) using mixed oligonucleotides corresponding to two regions of hevein as primers and a Hevea brasiliensis latex cDNA library as a template. HEV1 is 1018 nucleotides long and includes an open reading frame of 204 amino acids. The deduced amino acid sequence contains a pu GOVERNMENT RIGHTS This application was funded under Department of Energy Contract DE-AC02-76ER01338. The U.S. Government has certain rights under this application and any patent issuing thereon.

Governance of Offshore IT Outsourcing at Shell Global Functions IT-BAM Development and Application of a Governance Framework to Improve Outsourcing Relationships

NASA Astrophysics Data System (ADS)

de Jong, Floor; van Hillegersberg, Jos; van Eck, Pascal; van der Kolk, Feiko; Jorissen, Rene

The lack of effective IT governance is widely recognized as a key inhibitor to successful global IT outsourcing relationships. In this study we present the development and application of a governance framework to improve outsourcing relationships. The approach used to developing an IT governance framework includes a meta model and a customization process to fit the framework to the target organization. The IT governance framework consists of four different elements (1) organisational structures, (2) joint processes between in- and outsourcer, (3) responsibilities that link roles to processes and (4) a diverse set of control indicators to measure the success of the relationship. The IT governance framework is put in practice in Shell GFIT BAM, a part of Shell that concluded to have a lack of management control over at least one of their outsourcing relationships. In a workshop the governance framework was used to perform a gap analysis between the current and desired governance. Several gaps were identified in the way roles and responsibilities are assigned and joint processes are set-up. Moreover, this workshop also showed the usefulness and usability of the IT governance framework in structuring, providing input and managing stakeholders in the discussions around IT governance.

Structural insight into the substrate- and dioxygen-binding manner in the catalytic cycle of rieske nonheme iron oxygenase system, carbazole 1,9a-dioxygenase.

PubMed

Ashikawa, Yuji; Fujimoto, Zui; Usami, Yusuke; Inoue, Kengo; Noguchi, Haruko; Yamane, Hisakazu; Nojiri, Hideaki

2012-06-24

Dihydroxylation of tandemly linked aromatic carbons in a cis-configuration, catalyzed by multicomponent oxygenase systems known as Rieske nonheme iron oxygenase systems (ROs), often constitute the initial step of aerobic degradation pathways for various aromatic compounds. Because such RO reactions inherently govern whether downstream degradation processes occur, novel oxygenation mechanisms involving oxygenase components of ROs (RO-Os) is of great interest. Despite substantial progress in structural and physicochemical analyses, no consensus exists on the chemical steps in the catalytic cycles of ROs. Thus, determining whether conformational changes at the active site of RO-O occur by substrate and/or oxygen binding is important. Carbazole 1,9a-dioxygenase (CARDO), a RO member consists of catalytic terminal oxygenase (CARDO-O), ferredoxin (CARDO-F), and ferredoxin reductase. We have succeeded in determining the crystal structures of oxidized CARDO-O, oxidized CARDO-F, and both oxidized and reduced forms of the CARDO-O: CARDO-F binary complex. In the present study, we determined the crystal structures of the reduced carbazole (CAR)-bound, dioxygen-bound, and both CAR- and dioxygen-bound CARDO-O: CARDO-F binary complex structures at 1.95, 1.85, and 2.00 Å resolution. These structures revealed the conformational changes that occur in the catalytic cycle. Structural comparison between complex structures in each step of the catalytic mechanism provides several implications, such as the order of substrate and dioxygen bindings, the iron-dioxygen species likely being Fe(III)-(hydro)peroxo, and the creation of room for dioxygen binding and the promotion of dioxygen binding in desirable fashion by preceding substrate binding. The RO catalytic mechanism is proposed as follows: When the Rieske cluster is reduced, substrate binding induces several conformational changes (e.g., movements of the nonheme iron and the ligand residue) that create room for oxygen binding. Dioxygen bound in a side-on fashion onto nonheme iron is activated by reduction to the peroxo state [Fe(III)-(hydro)peroxo]. This state may react directly with the bound substrate, or O-O bond cleavage may occur to generate Fe(V)-oxo-hydroxo species prior to the reaction. After producing a cis-dihydrodiol, the product is released by reducing the nonheme iron. This proposed scheme describes the catalytic cycle of ROs and provides important information for a better understanding of the mechanism.

A reaction mechanism-based prediction of mutagenicity: α-halo carbonyl compounds adduct with DNA by SN2 reaction.

PubMed

Haranosono, Yu; Ueoka, Hiroki; Kito, Gakushi; Nemoto, Shingo; Kurata, Masaaki; Sakaki, Hideyuki

2018-01-01

Most of the α-halo carbonyl (AHC) compounds tend to be predicted as mutagenic by structure-activity relationship based on structural category only, because they have an alkyl halide structure as a structural alert of mutagenicity. However, some AHC compounds are not mutagenic. We hypothesized that AHC reacts with DNA by S N 2 reaction, and the reactivity relates to mutagenicity. As an index of S N 2 reactivity, we focused on molecular orbitals (MOs), as the direction and position of two molecules in collision are important in the S N 2 reaction. The MOs suitable for S N 2 reaction (SN2MOs) were selected by chemical-visual inspection based on the shape of the MO. We used the level gap and the energy gap between SN2MO and the lowest unoccupied molecular orbital as the descriptors of S N 2 reactivity. As the results, S N 2 reactivity related to mutagenicity and we were able to predict mutagenicity of 20 AHC compounds with 95.0% concordance. It was suggested that S N 2 reaction is a reaction mechanism of AHC compounds and DNA in the mutagenic process. The method allows for discrimination among structurally similar compounds by combination with quantitative structure-activity relationships. The combination approach is expected to be useful for the mutagenic assessment of pharmaceutical impurities.

Dichotomous-noise-induced pattern formation in a reaction-diffusion system

NASA Astrophysics Data System (ADS)

Das, Debojyoti; Ray, Deb Shankar

2013-06-01

We consider a generic reaction-diffusion system in which one of the parameters is subjected to dichotomous noise by controlling the flow of one of the reacting species in a continuous-flow-stirred-tank reactor (CSTR) -membrane reactor. The linear stability analysis in an extended phase space is carried out by invoking Furutzu-Novikov procedure for exponentially correlated multiplicative noise to derive the instability condition in the plane of the noise parameters (correlation time and strength of the noise). We demonstrate that depending on the correlation time an optimal strength of noise governs the self-organization. Our theoretical analysis is corroborated by numerical simulations on pattern formation in a chlorine-dioxide-iodine-malonic acid reaction-diffusion system.

The sonochemical arylation of malonic esters mediated by manganese triacetate.

PubMed

Meciarova, M; Toma, S; Luche, J L

2001-04-01

The intermolecular arylation of malonate esters in acetic acid solution in the presence of manganese(III) triacetate is known to proceed via an Electron Transfer mechanism. Under sonication, this reaction undergoes only minor changes. In contrast, the intramolecular reaction of dimethyl alpha-(3-phenylpropyl)malonate provides a new case of sonochemical switching, with the formation of compounds 7-9, while conventional thermal conditions generate only the bicyclic compound 6. Reactions using the more powerful oxidant, cerium ammonium nitrate are governed by the formation of the nitrate ester 11. Compounds 7-9 are isolated in yields lower than with MnTA, and in proportions depending on the conditions, thermal or sonochemical.

Activation barriers for methylation of DNA bases by dimethyl sulfate

NASA Astrophysics Data System (ADS)

Eichler, Daniel R.; Papadantonakis, George A.

2017-12-01

The SN2 transition states of the methylation reaction of DNA bases with dimethyl sulfate were examined employing DFT/ M06-2X/6-31+G∗ and DFT/B3LYP-D3/6-311+G (2df, 2p) levels of theory. Solvation effects were examined using the conductor-like polarizable continuum model (CPCM). Calculation results and feedback from electrostatic potential maps show that in water, charge separation lowers the activation barriers relative to the gas phase for the reactions at N7 of guanine, N3 of adenine and cytosine. Also, the reaction at the O6 site of guanine is governed by steric interference and exhibits a higher activation barrier in water.

Experimental study of 38Ar+α reaction cross sections relevant to the 41Ca abundance in the solar system

NASA Astrophysics Data System (ADS)

Talwar, R.; Bojazi, M. J.; Mohr, P.; Auranen, K.; Avila, M. L.; Ayangeakaa, A. D.; Harker, J.; Hoffman, C. R.; Jiang, C. L.; Kuvin, S. A.; Meyer, B. S.; Rehm, K. E.; Santiago-Gonzalez, D.; Sethi, J.; Ugalde, C.; Winkelbauer, J. R.

2018-05-01

In massive stars, the 41Ca(n ,α )38Ar and 41K(p ,α )38Ar reactions have been identified as the key reactions governing the abundance of 41Ca, which is considered as a potential chronometer for solar system formation. So far, due to experimental limitations, the 41Ca(n ,α )38Ar reaction rate is solely based on statistical model calculations. In the present study, we have measured the time-inverse 38Ar(α ,n )41Ca and 38Ar(α ,p )41K reactions using an active target detector. The reactions were studied in inverse kinematics using a 133-MeV 38Ar beam and 4He as the active-gas target. Both excitation functions were measured simultaneously in the energy range of 6.8 ≤Ec .m .≤9.3 MeV. Using detailed balance the 41Ca(n ,α )38Ar and 41K(p ,α )38Ar reaction rates were determined, which suggested a 20% increase in the 41Ca yield from massive stars.

Analysis of the Governance Structures in Japan's Biosphere Reserves: Perspectives from Bottom-Up and Multilevel Characteristics.

PubMed

Tanaka, Toshinori; Wakamatsu, Nobuhiko

2018-01-01

This paper analyzes the governance structures of Biosphere Reserves (BRs) in Japan by focusing on six criteria that elucidate the main characteristics therein: general information (nomination process, year of designation, size, and population), legal frameworks, stakeholder identification, and decision-making processes (number of municipalities and role of consociation), administrative institutions (human resources, budgetary situation, and expense distribution), executed BR implementation activities, and participatory/collaborative frameworks. This research consists of a literature review, a questionnaire administered to the secretariats of seven existing BRs and follow-up interviews. Three main characteristics of BRs were identified. First, a responsible local government(s) is nominated to manage the BR rather than the central government. Consequently, BR implementation in Japan is led by those municipalities that have strong motivations for regional development using the BR concept. Second, two types of BR governance structures exist in Japan: the single municipality type and the multi-municipality type. All BRs have so called Kyougikai, a consociation for decision-making, consultation and/or collaboration among stakeholders. In the single municipality structure, the consociation includes diverse actors from private and community sectors, while in the multi-municipality structure, consociations are based in more diplomatic settings and only include members of the public sector. Third, gaps between pre/post-Seville BR implementation sites were identified. The motivations for the formation of pre-Seville BRs, which were designated in 1980 in a top-down fashion prior to an awareness of BRs, varied greatly from those BRs nominated by municipalities after 2010. The authors identified fewer administrative resources and activities associated with the pre-Seville sites.

Analysis of the Governance Structures in Japan's Biosphere Reserves: Perspectives from Bottom-Up and Multilevel Characteristics

NASA Astrophysics Data System (ADS)

Tanaka, Toshinori; Wakamatsu, Nobuhiko

2018-01-01

This paper analyzes the governance structures of Biosphere Reserves (BRs) in Japan by focusing on six criteria that elucidate the main characteristics therein: general information (nomination process, year of designation, size, and population), legal frameworks, stakeholder identification, and decision-making processes (number of municipalities and role of consociation), administrative institutions (human resources, budgetary situation, and expense distribution), executed BR implementation activities, and participatory/collaborative frameworks. This research consists of a literature review, a questionnaire administered to the secretariats of seven existing BRs and follow-up interviews. Three main characteristics of BRs were identified. First, a responsible local government(s) is nominated to manage the BR rather than the central government. Consequently, BR implementation in Japan is led by those municipalities that have strong motivations for regional development using the BR concept. Second, two types of BR governance structures exist in Japan: the single municipality type and the multi-municipality type. All BRs have so called Kyougikai, a consociation for decision-making, consultation and/or collaboration among stakeholders. In the single municipality structure, the consociation includes diverse actors from private and community sectors, while in the multi-municipality structure, consociations are based in more diplomatic settings and only include members of the public sector. Third, gaps between pre/post-Seville BR implementation sites were identified. The motivations for the formation of pre-Seville BRs, which were designated in 1980 in a top-down fashion prior to an awareness of BRs, varied greatly from those BRs nominated by municipalities after 2010. The authors identified fewer administrative resources and activities associated with the pre-Seville sites.

MINERALOGICAL PRESERVATION OF SOLID SAMPLES COLLECTED FROM ANOXIC SUBSURFACE ENVIRONMENTS

EPA Science Inventory

Remedial technologies utilized at hazardous waste sites for the treatment of metal and metalloid contaminants often take advantage of reduction-oxidation (redox) processes to reach ground water clean up goals. This is because redox reactions, in many cases, govern the biogeochem...

Managing Multimedia Pollution for a Multimedia World

EPA Science Inventory

Through modest attention to the information highway we ride upon each day, we are increasingly aware of the intent, actions, and reactions of local, state and Federal governments, regional compacts, and international organizations to protect the quality of the water we drink, th...

IVI governance structure : enabling research and development

DOT National Transportation Integrated Search

1999-11-01

This Intelligent Vehicle Initiative (IVI) Governance Model is comprised of four programs. The first is "Enabling Research and Development", designed to provide a forum for industry and government to establish, prioritize, and evaluate IVI goals and r...

Informal Institutional Responses to Government Interventions: Lessons from Madhupur National Park, Bangladesh

NASA Astrophysics Data System (ADS)

Rahman, H. M. Tuihedur; Sarker, Swapan Kumar; Hickey, Gordon M.; Mohasinul Haque, M.; Das, Niamjit

2014-11-01

Madhupur National Park is renowned for severe resource ownership conflicts between ethnic communities and government authorities in Bangladesh. In this study, we applied the Institutional Analysis and Development framework to identify: (i) past and present informal institutional structures within the ethnic Garo community for land resource management; (ii) the origin of the land ownership dispute; (iii) interaction mechanisms between formal and informal institutions; and (iv) change in land management authority and informal governance structures. We identify that the informal institutions of the traditional community have undergone radical change due to government interventions with implications for the regulation of land use, informal institutional functions, and joint-decision-making. Importantly, the government's persistent denial of the role of existing informal institutions is widening the gap between government and community actors, and driving land ownership conflicts in a cyclic way with associated natural resource degradation.

Informal institutional responses to government interventions: lessons from Madhupur National Park, Bangladesh.

PubMed

Rahman, H M Tuihedur; Sarker, Swapan Kumar; Hickey, Gordon M; Mohasinul Haque, M; Das, Niamjit

2014-11-01

Madhupur National Park is renowned for severe resource ownership conflicts between ethnic communities and government authorities in Bangladesh. In this study, we applied the Institutional Analysis and Development framework to identify: (i) past and present informal institutional structures within the ethnic Garo community for land resource management; (ii) the origin of the land ownership dispute; (iii) interaction mechanisms between formal and informal institutions; and (iv) change in land management authority and informal governance structures. We identify that the informal institutions of the traditional community have undergone radical change due to government interventions with implications for the regulation of land use, informal institutional functions, and joint-decision-making. Importantly, the government's persistent denial of the role of existing informal institutions is widening the gap between government and community actors, and driving land ownership conflicts in a cyclic way with associated natural resource degradation.

Simulation in the Executive Suite: Lessons Learned for Building Patient Safety Leadership.

PubMed

Rosen, Michael A; Goeschel, Christine A; Che, Xin-Xuan; Fawole, Joseph Oluyinka; Rees, Dianne; Curran, Rosemary; Gelinas, Lillee; Martin, Jessica N; Kosel, Keith C; Pronovost, Peter J; Weaver, Sallie J

2015-12-01

Simulation is a powerful learning tool for building individual and team competencies of frontline health care providers with demonstrable impact on performance. This article examines the impact of simulation in building strategic leadership competencies for patient safety and quality among executive leaders in health care organizations. We designed, implemented, and evaluated a simulation as part of a larger safety leadership network meeting for executive leaders. This simulation targeted knowledge competencies of governance priority, culture of continuous improvement, and internal transparency and feedback. Eight teams of leaders in health care organizations-a total of 55 participants-participated in a 4-hour session. Each team performed collectively as a new chief executive officer (CEO) tasked with a goal of rescuing a hospital with a failing safety record. Teams worked on a modifiable simulation board reflecting the current dysfunctional organizational structure of the simulated hospital. They assessed and redesigned accountability structures based on information acquired in encounter sessions with confederates playing the role of internal staff and external consultants. Data were analyzed, and results are presented as qualitative themes arising from the simulation exercise, participant reaction data, and performance during the simulation. Key findings include high degrees of variability in solutions developed for the dysfunctional hospital system and generally positive learner reactions to the simulation experience. This study illustrates the potential value of simulation as a mechanism for learning and strategy development for executive leaders grappling with patient safety issues. Future research should explore the cognitive or functional fidelity of organizational simulations and the use of custom scenarios for strategic planning.

Multiple Facets of Candidate Image Structure: Effects of the McGovern Television Biography.

ERIC Educational Resources Information Center

Atwood, L. Erwin; And Others

In this comparison of the political "images" of Richard Nixon and George McGovern, public opinion data were collected on President Nixon in 1968 and 1972 and on Senator McGovern in 1972 just before and just after the television broadcast of the biography of McGovern. Changes in political attitudes toward Nixon and McGovern as a result of…

Design and analysis of linear cascade DNA hybridization chain reactions using DNA hairpins

NASA Astrophysics Data System (ADS)

Bui, Hieu; Garg, Sudhanshu; Miao, Vincent; Song, Tianqi; Mokhtar, Reem; Reif, John

2017-01-01

DNA self-assembly has been employed non-conventionally to construct nanoscale structures and dynamic nanoscale machines. The technique of hybridization chain reactions by triggered self-assembly has been shown to form various interesting nanoscale structures ranging from simple linear DNA oligomers to dendritic DNA structures. Inspired by earlier triggered self-assembly works, we present a system for controlled self-assembly of linear cascade DNA hybridization chain reactions using nine distinct DNA hairpins. NUPACK is employed to assist in designing DNA sequences and Matlab has been used to simulate DNA hairpin interactions. Gel electrophoresis and ensemble fluorescence reaction kinetics data indicate strong evidence of linear cascade DNA hybridization chain reactions. The half-time completion of the proposed linear cascade reactions indicates a linear dependency on the number of hairpins.

Political Governance and Conflict Management: Why Developing Polities and the Poor Need a Stronger State Structure?

ERIC Educational Resources Information Center

Forje, John W.

2006-01-01

Political governance and quality management are often contested concepts, meaning different things to different people; and often their meanings have shifted historically. The collapse of the governance system behind the iron curtain countries triggered an avalanche in international politics and instituted new governance and management system to…

Non-equilibrium dissipative supramolecular materials with a tunable lifetime

NASA Astrophysics Data System (ADS)

Tena-Solsona, Marta; Rieß, Benedikt; Grötsch, Raphael K.; Löhrer, Franziska C.; Wanzke, Caren; Käsdorf, Benjamin; Bausch, Andreas R.; Müller-Buschbaum, Peter; Lieleg, Oliver; Boekhoven, Job

2017-07-01

Many biological materials exist in non-equilibrium states driven by the irreversible consumption of high-energy molecules like ATP or GTP. These energy-dissipating structures are governed by kinetics and are thus endowed with unique properties including spatiotemporal control over their presence. Here we show man-made equivalents of materials driven by the consumption of high-energy molecules and explore their unique properties. A chemical reaction network converts dicarboxylates into metastable anhydrides driven by the irreversible consumption of carbodiimide fuels. The anhydrides hydrolyse rapidly to the original dicarboxylates and are designed to assemble into hydrophobic colloids, hydrogels or inks. The spatiotemporal control over the formation and degradation of materials allows for the development of colloids that release hydrophobic contents in a predictable fashion, temporary self-erasing inks and transient hydrogels. Moreover, we show that each material can be re-used for several cycles.

Physics through the 1990s: Atomic, molecular and optical physics

NASA Technical Reports Server (NTRS)

1986-01-01

The volume presents a program of research initiatives in atomic, molecular, and optical physics. The current state of atomic, molecular, and optical physics in the US is examined with respect to demographics, education patterns, applications, and the US economy. Recommendations are made for each field, with discussions of their histories and the relevance of the research to government agencies. The section on atomic physics includes atomic theory, structure, and dynamics; accelerator-based atomic physics; and large facilities. The section on molecular physics includes spectroscopy, scattering theory and experiment, and the dynamics of chemical reactions. The section on optical physics discusses lasers, laser spectroscopy, and quantum optics and coherence. A section elucidates interfaces between the three fields and astrophysics, condensed matter physics, surface science, plasma physics, atmospheric physics, and nuclear physics. Another section shows applications of the three fields in ultra-precise measurements, fusion, national security, materials, medicine, and other topics.

An approach for modeling thermal destruction of hazardous wastes in circulating fluidized bed incinerator.

PubMed

Patil, M P; Sonolikar, R L

2008-10-01

This paper presents a detailed computational fluid dynamics (CFD) based approach for modeling thermal destruction of hazardous wastes in a circulating fluidized bed (CFB) incinerator. The model is based on Eular - Lagrangian approach in which gas phase (continuous phase) is treated in a Eularian reference frame, whereas the waste particulate (dispersed phase) is treated in a Lagrangian reference frame. The reaction chemistry hasbeen modeled through a mixture fraction/ PDF approach. The conservation equations for mass, momentum, energy, mixture fraction and other closure equations have been solved using a general purpose CFD code FLUENT4.5. Afinite volume method on a structured grid has been used for solution of governing equations. The model provides detailed information on the hydrodynamics (gas velocity, particulate trajectories), gas composition (CO, CO2, O2) and temperature inside the riser. The model also allows different operating scenarios to be examined in an efficient manner.

Non-equilibrium dissipative supramolecular materials with a tunable lifetime

PubMed Central

Tena-Solsona, Marta; Rieß, Benedikt; Grötsch, Raphael K.; Löhrer, Franziska C.; Wanzke, Caren; Käsdorf, Benjamin; Bausch, Andreas R.; Müller-Buschbaum, Peter; Lieleg, Oliver; Boekhoven, Job

2017-01-01

Many biological materials exist in non-equilibrium states driven by the irreversible consumption of high-energy molecules like ATP or GTP. These energy-dissipating structures are governed by kinetics and are thus endowed with unique properties including spatiotemporal control over their presence. Here we show man-made equivalents of materials driven by the consumption of high-energy molecules and explore their unique properties. A chemical reaction network converts dicarboxylates into metastable anhydrides driven by the irreversible consumption of carbodiimide fuels. The anhydrides hydrolyse rapidly to the original dicarboxylates and are designed to assemble into hydrophobic colloids, hydrogels or inks. The spatiotemporal control over the formation and degradation of materials allows for the development of colloids that release hydrophobic contents in a predictable fashion, temporary self-erasing inks and transient hydrogels. Moreover, we show that each material can be re-used for several cycles. PMID:28719591

High-Temperature Nucleosynthesis Processes on the Proton-Rich Side of Stability: the Alpha-Rich Freezeout and the rp^2-Process

NASA Astrophysics Data System (ADS)

Meyer, Bradley S.

2001-10-01

Nucleosynthesis on the proton-rich side of stability has at least two intriguing aspects. First, the most abundant of the stable iron-group isotopes, such as ^48Ti, ^52Cr, and ^56,57Fe, are synthesized as proton-rich, radioactive parents in alpha-rich freezeouts from equilibrium. The production of these radioactive progenitors depends in large measure on reactions on the proton-rich side of stability. The second intriguing aspect is that explosive nucleosynthesis in a hydrogen-rich environment (namely, the rp-process) may be associated with exotic astrophysical settings, such as x-ray bursts, and may be responsible for production of some of the light p-process nuclei (for example, ^92,94Mo and ^96,98Ru). We have developed web-based tools to help nuclear physicists determine which nuclear reactions on the proton-rich side of stability govern the nucleosynthesis in these processes. For the alpha-rich freezeout, one may determine the effect of any one of 2,140 reactions on the yield of any isotope in the nuclear reaction network with the web calculator. As a relevant example, I will discuss the governing role of ^57Ni (n,p)^57Co in the synthesis of the important astronomical observable ^57Co. As for explosive, proton-rich burning, I will discuss the synthesis of p-process nuclei in the repetitive rp-process (the rp^2-process). Movies of the rp^2-process illustrate its important features and give some indications of the important nuclear reactions.

Analysis of Soil Structure Turnover with Garnet Particles and X-Ray Microtomography

PubMed Central

Vogel, Hans-Jörg

2016-01-01

Matter turnover in soil is tightly linked to soil structure which governs the heterogeneous distribution of habitats, reaction sites and pathways in soil. Thereby, the temporal dynamics of soil structure alteration is deemed to be important for essential ecosystem functions of soil but very little is known about it. A major reason for this knowledge gap is the lack of methods to study soil structure turnover directly at microscopic scales. Here we devise a conceptual approach and an image processing workflow to study soil structure turnover by labeling some initial state of soil structure with small garnet particles and tracking their fate with X-ray microtomography. The particles adhere to aggregate boundaries at the beginning of the experiment but gradually change their position relative to the nearest pore as structure formation progresses and pores are destructed or newly formed. A new metric based on the contact distances between particles and pores is proposed that allows for a direct quantification of soil structure turnover rates. The methodology is tested for a case study about soil compaction of a silty loam soil during stepwise increase of bulk density (ρ = {1.1, 1.3, 1.5} g/cm3). We demonstrate that the analysis of mean contact distances provides genuinely new insights about changing diffusion pathways that cannot be inferred neither from conventional pore space attributes (porosity, mean pore size, pore connectivity) nor from deformation analysis with digital image correlation. This structure labeling approach to quantify soil structure turnover provides a direct analogy to stable isotope labeling for the analysis of matter turnover and can be readily combined with each other. PMID:27453995

Another Milestone Day in AGU's History

NASA Astrophysics Data System (ADS)

Enderlein, Cheryl

2010-09-01

The AGU Board of Directors held its first board meeting on 20-21 September 2010 in Washington, D. C. The meeting, chaired by President Michael McPhaden, marked another step forward in implementing AGU's new governance structure and strategic direction. The agenda included ongoing organizational business, high-level strategic discussions, and opportunities for Board development. In the new governance structure, the Board is responsible for governing the business aspects of AGU, while the Council is responsible for governing scientific affairs. The strategic plan guides both governing groups, staff, and other membership groups by providing clear goals and objectives. Of the 28 objectives in the AGU strategic plan, the volunteer and staff leadership identified eight as priorities. The priority objectives are listed in the diagram to the right, which is also posted on the AGU Web site.

ISST (Intercontinental Ballistic Missile Silo Superhardening Technology) Structure with SIFCON (Slurry-Infiltrated Fiber Concrete) - HFC-2 Test

DTIC Science & Technology

1988-04-01

Government-related pro- curement, the United States Government incurs no responsibility or any obli -j gation whatsoever. The fact that the Government...Arizona. NIIERI then began a program to deveiop a slurry mix design for use in the structure, as well as construction techniques for placing the SIFCON in...OBJECTIVES 3 II CONSTRUCTION AND FIELDING OPERATIONS 4 INTRODUCTION 4 I DEMONSTRATION PROGRAM 4 Introduct ion 4 Procedure 4 Results 7 $ DESIGN 7 I ntrod uc

Do governance choices matter in health care networks?: an exploratory configuration study of health care networks.

PubMed

Willem, Annick; Gemmel, Paul

2013-06-24

Health care networks are widely used and accepted as an organizational form that enables integrated care as well as dealing with complex matters in health care. However, research on the governance of health care networks lags behind. The research aim of our study is to explore the type and importance of governance structure and governance mechanisms for network effectiveness. The study has a multiple case study design and covers 22 health care networks. Using a configuration view, combinations of network governance and other network characteristics were studied on the level of the network. Based on interview and questionnaire data, network characteristics were identified and patterns in the data looked for. Neither a dominant (or optimal) governance structure or mechanism nor a perfect fit among governance and other characteristics were revealed, but a number of characteristics that need further study might be related to effective networks such as the role of governmental agencies, legitimacy, and relational, hierarchical, and contractual governance mechanisms as complementary factors. Although the results emphasize the situational character of network governance and effectiveness, they give practitioners in the health care sector indications of which factors might be more or less crucial for network effectiveness.

[Study on X-ray powder diffraction of various structured zinc titanate prepared by the method of direct precipitation].

PubMed

Guo, Jian; Wang, Zhi-hua; Tao, Dong-liang; Guo, Guang-sheng

2007-05-01

Zinc titanate powders were prepared from Ti(SO4)2, Zn(NO3)2 x (6)H2O and (NH4)2CO3 by the method of direct precipitation. The effects of reaction conditions on the structure of zinc titanate were studied. The sample was analyzed by means of XRD and TG-DTA. The structure of zinc titanate was affected by the reaction subsequence of the formation of titanic acid and zinc carbonate. In the reaction system where titanic acid was generated earlier, collision reaction occurred between the generated zinc carbonate molecule and the surrounding titanic acid molecule. When titanic acid was generated earlier and precipitant (NH4)2CO3 was sufficient, Zn2Ti3O8 was obtained because of the sufficient collision reaction and superfluous titanic acid. In the reaction system where zinc carbonate was generated earlier, collision reaction occurred between the generated titanic acid molecule and the surrounding zinc carbonate molecule. When zinc carbonate was generated earlier and precipitant (NH4)2CO3 was sufficient, Zn2TiO4 was obtained because of the sufficient collision reaction and superfluous zinc carbonate. In addition, the kinds and structure of the production were affected by the dosage of precipitant and the reaction temperature. Zn2Ti3O8 or Zn2TiO4 could be obtained easier when using more precipitant or higher reaction temperature which could cause more sufficient collision reaction. ZnTiO3 could be obtained under the conditions of less precipitant and lower reaction temperature.

The structure of particle cloud premixed flames

NASA Technical Reports Server (NTRS)

Seshadri, K.; Berlad, A. L.

1992-01-01

The structure of premixed flames propagating in combustible systems containing uniformly distributed volatile fuel particles in an oxidizing gas mixture is analyzed. This analysis is motivated by experiments conducted at NASA Lewis Research Center on the structure of flames propagating in combustible mixtures of lycopodium particles and air. Several interesting modes of flame propagation were observed in these experiments depending on the number density and the initial size of the fuel particle. The experimental results show that steady flame propagation occurs even if the initial equivalence ratio of the combustible mixture based on the gaseous fuel available in the particles, phi sub u, is substantially larger than unity. A model is developed to explain these experimental observations. In the model, it is presumed that the fuel particles vaporize first to yield a gaseous fuel of known chemical composition which then reacts with oxygen in a one-step overall process. The activation energy of the chemical reaction is presumed to be large. The activation energy characterizing the kinetics of vaporization is also presumed to be large. The equations governing the structure of the flame were integrated numerically. It is shown that the interplay of vaporization kinetics and oxidation process can result in steady flame propagation in combustible mixtures where the value of phi sub u is substantially larger than unity. This prediction is in agreement with experimental observations.

Method for fabricating an ignitable heterogeneous stratified metal structure

DOEpatents

Barbee, T.W. Jr.; Weihs, T.

1996-08-20

A multilayer structure has a selectable: (1) propagating reaction front velocity V; (2) reaction initiation temperature attained by application of external energy; and (3) amount of energy delivered by a reaction of alternating unreacted layers of the multilayer structure. Because V is selectable and controllable, a variety of different applications for the multilayer structures are possible, including but not limited to their use as igniters, in joining applications, in fabrication of new materials, as smart materials and in medical applications and devices. The multilayer structure has a period D, and an energy release rate constant K. Two or more alternating unreacted layers are made of different materials and separated by reacted zones. The period D is equal to a sum of the widths of each single alternating reaction layer of a particular material, and also includes a sum of reacted zone widths, t{sub i}, in the period D. The multilayer structure has a selectable propagating reaction front velocity V, where V=K(1/D{sup n}){times}[1-(t{sub i}/D)] and n is about 0.8 to 1.2. 8 figs.

Method for fabricating an ignitable heterogeneous stratified metal structure

DOEpatents

Barbee, Jr., Troy W.; Weihs, Timothy

1996-01-01

A multilayer structure has a selectable, (i) propagating reaction front velocity V, (ii) reaction initiation temperature attained by application of external energy and (iii) amount of energy delivered by a reaction of alternating unreacted layers of the multilayer structure. Because V is selectable and controllable, a variety of different applications for the multilayer structures are possible, including but not limited to their use as ignitors, in joining applications, in fabrication of new materials, as smart materials and in medical applications and devices. The multilayer structure has a period D, and an energy release rate constant K. Two or more alternating unreacted layers are made of different materials and separated by reacted zones. The period D is equal to a sum of the widths of each single alternating reaction layer of a particular material, and also includes a sum of reacted zone widths, t.sub.i, in the period D. The multilayer structure has a selectable propagating reaction front velocity V, where V=K(1/D.sup.n).times.[1-(t.sub.i /D)]and n is about 0.8 to 1.2.

Settlement Patterns and the Governing Structures of 19th Century School Systems.

ERIC Educational Resources Information Center

Richardson, John G.

Examination of state school governance structures in the late 19th century reveals three regional models, each springing from particular patterns of settlement and political administration. Historical explanations for school system origins have drawn mainly on the histories of northeastern cities and states. They have underemphasized regional…

Federal Funds and State Interests: A Proposal for Governing the NAEP.

ERIC Educational Resources Information Center

Doyle, Denis P.

1983-01-01

Informational, diagnostic, prescriptive functions of National Assessment of Educational Progress (NAEP) are best served by governance structure composed of federal, state, and local members and a standing technical advisory board. Structure protects NAEP from undue federal influence and special interest groups, builds bridges to educators and…

18 CFR 375.308 - Delegations to the Director of the Office of Energy Projects.

Code of Federal Regulations, 2010 CFR

2010-04-01

... the Federal Power Act, where no substantive changes in ownership, corporate structure or domicile, or... government dams or other structures billed to licensees each year for contractual payments for the... resources projects submitted by other agencies of the Federal government for Commission review or comment...

Impact of Information Technology Governance Structures on Strategic Alignment

ERIC Educational Resources Information Center

Gordon, Fitzroy R.

2013-01-01

This dissertation is a study of the relationship between Information Technology (IT) strategic alignment and IT governance structure within the organization. This dissertation replicates Asante (2010) among a different population where the prior results continue to hold, the non-experimental approach explored two research questions but include two…

Evolved stars as complex chemical laboratories - the quest for gaseous chemistry

NASA Astrophysics Data System (ADS)

Katrien Els Decin, Leen

2015-08-01

At the end of their life, most stars lose a large fraction of their mass through a stellar wind. The stellar winds of evolved (super)giant stars are the dominant suppliers for the pristine building blocks of the interstellar medium (ISM). Crucial to the understanding of the chemical life cycle of the ISM is hence a profound insight in the chemical and physical structure governing these stellar winds.These winds are really unique chemical laboratories in which currently more than 70 different molecules and 15 different dust species are detected. Several chemical processes such as neutral-neutral and ion-molecule gas-phase reactions, dust nucleation and growth, and photo-processes determine the chemical content of these winds. However, gas-phase and dust-nucleation chemistry for astronomical environments still faces many challenges. One should realize that only ˜15% of the rate coefficients for gas-phase reactions considered to occur in (inter/circum)stellar regions at temperatures (T) below 300K have been subject to direct laboratory determinations and that the temperature dependence of the rate constants is often not known; only ˜2% have rate constants at T<200K and less than 0.5% at T<100 K. For stellar wind models, an important bottleneck occurs among the reactions involving silicon- and sulfur-bearing species, for which only a few have documented reaction rates. Often, researchers are implementing ‘educated guesses’ for these unknown rates, sometimes forcing the network to yield predictions concurring with (astronomical) observations. Large uncertainties are inherent in this type of ‘optimized’ chemical schemes.Thanks to an ERC-CoG grant, we are now in the position to solve some riddles involved in understanding the gas-phase chemistry in evolved stars. In this presentation, I will demonstrate the need for accurate temperature-dependent gas-phase reaction rate constants and will present our new laboratory equipment built to measure the rate constants for species key in stellar wind chemistry. Specifically, we aim to obtain the rate constants of reactions involving silicon- and sulphur bearing species and HCCO for 30

Key parameters controlling the performance of catalytic motors.

PubMed

Esplandiu, Maria J; Afshar Farniya, Ali; Reguera, David

2016-03-28

The development of autonomous micro/nanomotors driven by self-generated chemical gradients is a topic of high interest given their potential impact in medicine and environmental remediation. Although impressive functionalities of these devices have been demonstrated, a detailed understanding of the propulsion mechanism is still lacking. In this work, we perform a comprehensive numerical analysis of the key parameters governing the actuation of bimetallic catalytic micropumps. We show that the fluid motion is driven by self-generated electro-osmosis where the electric field originates by a proton current rather than by a lateral charge asymmetry inside the double layer. Hence, the surface potential and the electric field are the key parameters for setting the pumping strength and directionality. The proton flux that generates the electric field stems from the proton gradient induced by the electrochemical reactions taken place at the pump. Surprisingly the electric field and consequently the fluid flow are mainly controlled by the ionic strength and not by the conductivity of the solution, as one could have expected. We have also analyzed the influence of the chemical fuel concentration, electrochemical reaction rates, and size of the metallic structures for an optimized pump performance. Our findings cast light on the complex chemomechanical actuation of catalytic motors and provide important clues for the search, design, and optimization of novel catalytic actuators.

Interaction of Black Phosphorus with Oxygen and Water

DOE PAGES

Huang, Yuan; Qiao, Jingsi; He, Kai; ...

2016-10-24

Black phosphorus (BP) has attracted significant interest as a monolayer or few-layer material with extraordinary electrical and optoelectronic properties. Chemical reactions with different ambient species, notably oxygen and water, are important as they govern key properties such as stability in air, electronic structure and charge transport, wetting by aqueous solutions, etc. Here, we report experiments combined with ab-initio calculations that address the effects of oxygen and water in contact with BP. Our results show that the reaction with oxygen is primarily responsible for changing properties of BP. Oxidation involving the dissociative chemisorption of O 2 causes the decomposition of BPmore » and continuously lowers the conductance of BP field-effect transistors (FETs). In contrast, BP is stable in contact with deaerated (i.e., O 2 depleted) water and the carrier mobility in BP FETs gated by H 2O increases significantly due to efficient dielectric screening of scattering centers by the high-k dielectric. Isotope labeling experiments, contact angle measurements and calculations show that the pristine BP surface is hydrophobic, but is turned progressively hydrophilic by oxidation. Lastly, our results open new avenues for exploring applications that require contact of BP with aqueous solutions including solution gating, electrochemistry, and solution-phase approaches for exfoliation, dispersion, and delivery of BP.« less

Evolution of streamer groups in nonthermal plasma

NASA Astrophysics Data System (ADS)

Okubo, M.

2015-12-01

Nonthermal plasmas (NTPs) induced by atmospheric nanosecond pulsed corona discharge have been studied for controlling pollution from combustors, such as boilers, incinerators, and diesel engines. In high-speed short-width high-voltage pulsed corona discharge-induced plasmas, primary streamer evolution is followed by secondary streamer evolution. Though this phenomenon is known experimentally, the details of the structures of the streamers and their evolution mechanisms have not been fully clarified. In this letter, we perform quasi two-dimensional numerical analysis of nonequilibrium NTP induced by a nanosecond positive pulsed corona discharge. The continuum fluid equations for two-temperature nonequilibrium NTP are used as governing equations. In this study, 197 gas phase reactions for 25 chemical species and 21 surface reactions on the inner glass wall surface are considered in an air plasma under atmospheric pressure. The simulated behavior of the streamer groups agrees with experimental observations. Soon after the voltage increases on the reactor, primary streamers are formed, which may transit the complete gap, disappearing near the peak voltage. Next, second streamers appear, disappearing at the end of the applied voltage pulse. The streamer wavelength and the distance between the streamers in the axial direction are determined. Moreover, ozone generation is shown to be more significant in the secondary streamer. This simulation will allow better predictions for nanosecond positive pulsed plasma systems.

MODELING MONOMETHYLMERCURY AND TRIBUTYLTIN SPECIATION WITH EPA'S GEOCHEMICAL SPECIATION MODEL MINTEQA2

EPA Science Inventory

Given the complexity of the various, simultaneous (and competing) equilibrium reactions governing the speciation of ionic species in aquatic systems, EPA has developed and distributed the geochemical speciation model MINTEQA2 (Brown and Allison, 1987, Allison et al., 1991; Hydrog...

Reforming the Madrassah System of Education in Pakistan

ERIC Educational Resources Information Center

Inamullah, Hafiz Muhammad; Hifazatullah, Hafiz; Sarwar, Muhammad; Khan, Naeemullah; Sultan, Khalid

2010-01-01

The unfortunate attacks of 9/11 forced the government to reform madrassah education programs. The aim of this article is to discuss the reform and its results and points of view, as well as the reaction of the Islamic seminaries toward these madrassah reforms.

Port Sivad: A Locational Decision Game for a Noxious Public Facility

ERIC Educational Resources Information Center

Jakubs, John F.; And Others

1977-01-01

Described is a simulation game concerned with the expeditious location of a sewage plant in a hypothetical urban area. Over 15 college or high school students can play the game, which involves government bargaining, citizen reaction, and side payments. (Author/AV)

RESEARCH ACTIVITIES AT U.S. GOVERNMENT AGENCIES IN SUBSURFACE REACTIVE TRANSPORT MODELING

EPA Science Inventory

The fate of contaminants in the environment is controlled by both chemical reactions and transport phenomena in the subsurface. Our ability to understand the significance of these processes over time requires an accurate conceptual model that incorporates the various mechanisms ...

Principles Governing the Mechanics and Control of Snake Strikes

DTIC Science & Technology

2015-06-26

Zoo Atlanta. In this exploratory project we will monitor kinematics, ground reaction forces and strike forces in snakes to gain insight into common...species once Zoo Atlanta is again open for research collaboration; their renovation and expansion of herpetological facility has limited our

Alkalizing Reactions Streamline Cellular Metabolism in Acidogenic Microorganisms

PubMed Central

Arioli, Stefania; Ragg, Enzio; Scaglioni, Leonardo; Fessas, Dimitrios; Signorelli, Marco; Karp, Matti; Daffonchio, Daniele; De Noni, Ivano; Mulas, Laura; Oggioni, Marco; Guglielmetti, Simone; Mora, Diego

2010-01-01

An understanding of the integrated relationships among the principal cellular functions that govern the bioenergetic reactions of an organism is necessary to determine how cells remain viable and optimise their fitness in the environment. Urease is a complex enzyme that catalyzes the hydrolysis of urea to ammonia and carbonic acid. While the induction of urease activity by several microorganisms has been predominantly considered a stress-response that is initiated to generate a nitrogen source in response to a low environmental pH, here we demonstrate a new role of urease in the optimisation of cellular bioenergetics. We show that urea hydrolysis increases the catabolic efficiency of Streptococcus thermophilus, a lactic acid bacterium that is widely used in the industrial manufacture of dairy products. By modulating the intracellular pH and thereby increasing the activity of β-galactosidase, glycolytic enzymes and lactate dehydrogenase, urease increases the overall change in enthalpy generated by the bioenergetic reactions. A cooperative altruistic behaviour of urease-positive microorganisms on the urease-negative microorganisms within the same environment was also observed. The physiological role of a single enzymatic activity demonstrates a novel and unexpected view of the non-transcriptional regulatory mechanisms that govern the bioenergetics of a bacterial cell, highlighting a new role for cytosol-alkalizing biochemical pathways in acidogenic microorganisms. PMID:21152088

School Governance in Switzerland: Tensions between New Roles and Old Traditions

ERIC Educational Resources Information Center

Huber, Stephan Gerhard

2011-01-01

This article analyses school governance in Switzerland. It elaborates on the different actors involved, their roles and functions, and how these change as school governance in the cantons changes. Quality management is identified as a core activity at all levels and for all actors involved in school governance. In these re-structuring processes,…

Bringing Democratic Governance into Practice: Policy Enactments Responding to Neoliberal Governance in Spanish Public Schools

ERIC Educational Resources Information Center

Prieto-Flores, Òscar; Feu, Jordi; Serra, Carles; Lázaro, Laura

2018-01-01

This article explores different ways in which public primary schools sustain democratic governance structures created beyond those mandated by law in Spain. These new institutional designs, while not opposed to policy text requirements of having a governing body with representatives of parents, teachers and public administration, are being carried…

County Government in Georgia [And] Teacher's Manual for County Government in Georgia.

ERIC Educational Resources Information Center

Hepburn, Mary A.

The student textbook and the teacher's manual focus on the services, organization, and funding of county government in Georgia. Designed to be used over a three to six week period, the textbook is arranged into six chapters. Chapter one discusses county government, its services, and its structure. Chapter two focuses on county officials and their…

Nuevos patrones en el gobierno de los colegios (New Patterns of School Governance). ERIC Digest.

ERIC Educational Resources Information Center

Renchler, Ron

This digest in Spanish explains why public-school governance is receiving increasing scrutiny. It identifies who is held accountable for results in the current governance system and describes recent proposals for transforming governance structures. Since many reforms of the past decade bypassed the school board and district office, reformers are…

Exploring the Complex Interaction between Governance and Knowledge in Education. OECD Education Working Papers, No. 67

ERIC Educational Resources Information Center

Fazekas, Mihaly; Burns, Tracey

2012-01-01

Governments in all Organisation for Economic Cooperation and Development (OECD) countries are facing the challenge of governing increasingly complex education systems. There is a growing need for governance structures that can handle this complexity and which can provide actors with the knowledge they need to make decisions. This working paper…

Mental health network governance: comparative analysis across Canadian regions

PubMed Central

Wiktorowicz, Mary E; Fleury, Marie-Josée; Adair, Carol E; Lesage, Alain; Goldner, Elliot; Peters, Suzanne

2010-01-01

Objective Modes of governance were compared in ten local mental health networks in diverse contexts (rural/urban and regionalized/non-regionalized) to clarify the governance processes that foster inter-organizational collaboration and the conditions that support them. Methods Case studies of ten local mental health networks were developed using qualitative methods of document review, semi-structured interviews and focus groups that incorporated provincial policy, network and organizational levels of analysis. Results Mental health networks adopted either a corporate structure, mutual adjustment or an alliance governance model. A corporate structure supported by regionalization offered the most direct means for local governance to attain inter-organizational collaboration. The likelihood that networks with an alliance model developed coordination processes depended on the presence of the following conditions: a moderate number of organizations, goal consensus and trust among the organizations, and network-level competencies. In the small and mid-sized urban networks where these conditions were met their alliance realized the inter-organizational collaboration sought. In the large urban and rural networks where these conditions were not met, externally brokered forms of network governance were required to support alliance based models. Discussion In metropolitan and rural networks with such shared forms of network governance as an alliance or voluntary mutual adjustment, external mediation by a regional or provincial authority was an important lever to foster inter-organizational collaboration. PMID:21289999

My daily constitutional in martinsried.

PubMed

Allen, James P

2004-01-01

The three-dimensional structures of bacterial reaction centers have served as the framework for much of our understanding of anoxygenic photosynthesis. A key step in the determination of the structure of the reaction center from Rhodobacter sphaeroides was the use the molecular replacement technique. For this technique, we made use of two sets of data. First, X-ray diffraction data had been measured from crystals of the reaction center from R. sphaeroides by our research group in California, led by George Feher and Douglas Rees. The second data set consisted of the coordinates of the three-dimensional structure of the reaction center from Rhodopseudomonas (now Blastochloris) viridis, which had been solved in the pioneering efforts of a group in Martinsried, led by Johann Deisenhofer, Robert Huber and Hartmut Michel. The collaborative efforts of these two groups to determine the structure of the reaction center from R. sphaeroides is described.

Assessing the superelectrophilic dimension through sigma-complexation, SNAr and Diels-Alder reactivity.

PubMed

Buncel, Erwin; Terrier, François

2010-05-21

In the domain of organic chemistry, S(N)Ar substitutions represent a class of reactions of overwhelming importance, both in synthesis and in the understanding of structure-reactivity relationships, especially the role of sigma-complex intermediates. The primary factor necessary for achievement of S(N)Ar reactions is the presence of a good leaving group, which allows facile rearomatization of the ring undergoing nucleophilic attack. Consistent is the finding that the superelectrophilic chloronitrobenzofuroxans--or furazans--exhibit a very high S(N)Ar reactivity, allowing a number of C-C, C-N, C-O couplings to be achieved that are not accessible with the classical series of nitro-substituted aromatics. Of particular interest is the synthesis of a number of indoles, indolizines, pyrroles and extended pi-excessive aromatic structures like azulene substituted by superelectrophilic moieties. The remarkable driving force for the facile completion of these reactions is the 10 orders of magnitude greater reactivity of 10pi-electron-deficient heteroaromatics such as 4,6-dinitrobenzofuroxan (DNBF) than of the most reactive trinitrobenzene derivatives in sigma-adduct complexation. Among the factors that have been recognized as governing superelectrophilicity, there is the poor aromaticity of 6-membered 10pi-electron structures investigated, with a common origin for sigma-complexation and pericyclic processes. A remarkable capacity of these structures is actually to contribute to a variety of Diels-Alder reactions. As an example, the DNBF molecule formally behaves as a nitroalkene, being susceptible to act as a dienophile as well as a heterodiene. Another remarkable Diels-Alder pathway is the capacity of the 6-membered carbocyclic ring of DNBF to act as a carbodiene. Also noteworthy is the successful Diels-Alder trapping of the dinitroso intermediate associated with 1-oxide/3-oxide tautomerism of the furoxan moiety of 4-aza-6-nitrobenzofuroxan. A point of fundamental importance in taking advantage of the reactivity of superelectrophilic structures at hand has been a successful calibration of their reactivity within the electrophilicity E scale developed by Mayr to describe nucleophile-electrophile combinations in general. It has thus been established that the E parameters measuring the electrophilicity of neutral heteroaromatics lie in the same region of the E scale as a number of highly reactive cationic reagents. Besides a reactivity rather similar to that of the 4-nitrobenzenediazonium cation (vide supra), the most electrophilic neutral molecules (DNBF, DNTP, DNBZ) are as electrophilic as tropylium cations or a number of metal-coordinated carbenium ions. Furthermore, there is a remarkable link between the pK(a)(H(2)O) and E scales, as evidenced by the existence of a unique linear relationship spanning more than 20 orders of reactivity. This relationship appears as being a nice probe to predict the feasibility of S(N)Ar substitutions and related sigma-complexation processes. Also revealing in terms of feasibility of the reactions is the existence of a close correlation between the electrochemical oxidation potential E degrees of sigma-adducts and their positioning on the pK(a)(H(2)O) scale. Our data can also be used to evaluate the potential of a theoretical model recently derived from DFT calculations, namely the global electrophilicity index omega, for the description of nucleophile-electrophile combinations. While showing several significant deviations, a reasonably linear omega vs. pK(a)(H(2)O) relationship is obtained when restricting the correlation to structurally similar electrophilic moieties. On this basis, valuable information could be derived regarding the polar character of some DA reactions. Overall, the global electrophilicity (omega) approach may be a promising avenue in future work of electrophile-nucleophile combinations.

The three-dimensional structures of bacterial reaction centers.

PubMed

Olson, T L; Williams, J C; Allen, J P

2014-05-01

This review presents a broad overview of the research that enabled the structure determination of the bacterial reaction centers from Blastochloris viridis and Rhodobacter sphaeroides, with a focus on the contributions from Duysens, Clayton, and Feher. Early experiments performed in the laboratory of Duysens and others demonstrated the utility of spectroscopic techniques and the presence of photosynthetic complexes in both oxygenic and anoxygenic photosynthesis. The laboratories of Clayton and Feher led efforts to isolate and characterize the bacterial reaction centers. The availability of well-characterized preparations of pure and stable reaction centers allowed the crystallization and subsequent determination of the structures using X-ray diffraction. The three-dimensional structures of reaction centers revealed an overall arrangement of two symmetrical branches of cofactors surrounded by transmembrane helices from the L and M subunits, which also are related by the same twofold symmetry axis. The structure has served as a framework to address several issues concerning bacterial photosynthesis, including the directionality of electron transfer, the properties of the reaction center-cytochrome c 2 complex, and the coupling of proton and electron transfer. Together, these research efforts laid the foundation for ongoing efforts to address an outstanding question in oxygenic photosynthesis, namely the molecular mechanism of water oxidation.

[The regionalized healthcare network in Santa Catarina State, Brazil, from 2011 to 2015: governance system and oral healthcare].

PubMed

Godoi, Heloisa; Andrade, Selma Regina de; Mello, Ana Lúcia Schaefer Ferreira de

2017-09-28

: The objective was to describe the governance system used in structuring the regionalized healthcare network in Santa Catarina State, Brazil, based on the Bipartite Inter-Managerial Commission (CIB), with a focus on structuring of oral healthcare. This was a qualitative, exploratory-descriptive documental study, based on the foundations of governance as an analytical tool through identification of the dimensions actors, norms, nodal points, and processes. Secondary data were collected from the minutes of CIB meetings held from January 2011 to December 2015. The analysis shows weaknesses in CIB governance in Santa Catarina in relation to regionalized structuring of oral healthcare from a network perspective. Structuring of oral healthcare occurs in parallel to that of other thematic networks in the state and shows the expansion of dental services, especially those with medium complexity, as an effect of the prevailing governance process. The relations established between administrators and decision-making processes allowed recognizing this network's "prescription", since there is little negotiation and local demand, limited more to following recommendations and incentives from the federal/state sphere, intermediated by staff from the State Health Secretariat. Thus, setting a policy agenda for oral healthcare for the population of Santa Catarina is weakened, with a peripheral position in relation to other health programs.

Decomposition of metabolic network into functional modules based on the global connectivity structure of reaction graph.

PubMed

Ma, Hong-Wu; Zhao, Xue-Ming; Yuan, Ying-Jin; Zeng, An-Ping

2004-08-12

Metabolic networks are organized in a modular, hierarchical manner. Methods for a rational decomposition of the metabolic network into relatively independent functional subsets are essential to better understand the modularity and organization principle of a large-scale, genome-wide network. Network decomposition is also necessary for functional analysis of metabolism by pathway analysis methods that are often hampered by the problem of combinatorial explosion due to the complexity of metabolic network. Decomposition methods proposed in literature are mainly based on the connection degree of metabolites. To obtain a more reasonable decomposition, the global connectivity structure of metabolic networks should be taken into account. In this work, we use a reaction graph representation of a metabolic network for the identification of its global connectivity structure and for decomposition. A bow-tie connectivity structure similar to that previously discovered for metabolite graph is found also to exist in the reaction graph. Based on this bow-tie structure, a new decomposition method is proposed, which uses a distance definition derived from the path length between two reactions. An hierarchical classification tree is first constructed from the distance matrix among the reactions in the giant strong component of the bow-tie structure. These reactions are then grouped into different subsets based on the hierarchical tree. Reactions in the IN and OUT subsets of the bow-tie structure are subsequently placed in the corresponding subsets according to a 'majority rule'. Compared with the decomposition methods proposed in literature, ours is based on combined properties of the global network structure and local reaction connectivity rather than, primarily, on the connection degree of metabolites. The method is applied to decompose the metabolic network of Escherichia coli. Eleven subsets are obtained. More detailed investigations of the subsets show that reactions in the same subset are really functionally related. The rational decomposition of metabolic networks, and subsequent studies of the subsets, make it more amenable to understand the inherent organization and functionality of metabolic networks at the modular level. http://genome.gbf.de/bioinformatics/

Evolving polycentric governance of the Great Barrier Reef

PubMed Central

Morrison, Tiffany H.

2017-01-01

A growing field of sustainability science examines how environments are transformed through polycentric governance. However, many studies are only snapshot analyses of the initial design or the emergent structure of polycentric regimes. There is less systematic analysis of the longitudinal robustness of polycentric regimes. The problem of robustness is approached by focusing not only on the structure of a regime but also on its context and effectiveness. These dimensions are examined through a longitudinal analysis of the Great Barrier Reef (GBR) governance regime, drawing on in-depth interviews and demographic, economic, and employment data, as well as organizational records and participant observation. Between 1975 and 2011, the GBR regime evolved into a robust polycentric structure as evident in an established set of multiactor, multilevel arrangements addressing marine, terrestrial, and global threats. However, from 2005 onward, multiscale drivers precipitated at least 10 types of regime change, ranging from contextual change that encouraged regime drift to deliberate changes that threatened regime conversion. More recently, regime realignment also has occurred in response to steering by international organizations and shocks such as the 2016 mass coral-bleaching event. The results show that structural density and stability in a governance regime can coexist with major changes in that regime’s context and effectiveness. Clear analysis of the vulnerability of polycentric governance to both diminishing effectiveness and the masking effects of increasing complexity provides sustainability science and governance actors with a stronger basis to understand and respond to regime change. PMID:28348238

Evolving polycentric governance of the Great Barrier Reef.

PubMed

Morrison, Tiffany H

2017-04-11

A growing field of sustainability science examines how environments are transformed through polycentric governance. However, many studies are only snapshot analyses of the initial design or the emergent structure of polycentric regimes. There is less systematic analysis of the longitudinal robustness of polycentric regimes. The problem of robustness is approached by focusing not only on the structure of a regime but also on its context and effectiveness. These dimensions are examined through a longitudinal analysis of the Great Barrier Reef (GBR) governance regime, drawing on in-depth interviews and demographic, economic, and employment data, as well as organizational records and participant observation. Between 1975 and 2011, the GBR regime evolved into a robust polycentric structure as evident in an established set of multiactor, multilevel arrangements addressing marine, terrestrial, and global threats. However, from 2005 onward, multiscale drivers precipitated at least 10 types of regime change, ranging from contextual change that encouraged regime drift to deliberate changes that threatened regime conversion. More recently, regime realignment also has occurred in response to steering by international organizations and shocks such as the 2016 mass coral-bleaching event. The results show that structural density and stability in a governance regime can coexist with major changes in that regime's context and effectiveness. Clear analysis of the vulnerability of polycentric governance to both diminishing effectiveness and the masking effects of increasing complexity provides sustainability science and governance actors with a stronger basis to understand and respond to regime change.

Space strategy and governance of ESA small member states

NASA Astrophysics Data System (ADS)

Sagath, Daniel; Papadimitriou, Angeliki; Adriaensen, Maarten; Giannopapa, Christina

2018-01-01

The European Space Agency (ESA) has twenty-two Member States with a variety of governance structures and strategic priorities regarding their space activities. The objective of this paper is to provide an up-to date overview and a holistic assessment of the national space governance structures and strategic priorities of the eleven smaller Member States (based on annual ESA contributions). A link is made between the governance structure and the main strategic objectives. The specific needs and interests of small and new Member States in the frame of European Space Integration are addressed. The first part of the paper focuses on the national space governance structures in the eleven smaller ESA Member States. The governance models of these Member States are identified including the responsible ministries and the entities entrusted with the implementation of space strategy/policy and programmes of the country. The second part of this paper focuses on the content and analysis of the national space strategies and indicates the main priorities and trends in the eleven smaller ESA Member States. The priorities are categorised with regards to technology domains, the role of space in the areas of sustainability and the motivators for space investments. In a third and final part, attention is given to the specific needs and interests of the smaller Member States in the frame of European space integration. ESA instruments are tailored to facilitate the needs and interests of the eleven smaller and/or new Member States.

Intermediate-energy inverse-kinematics one-proton pickup reactions on neutron-deficient fp-shell nuclei

NASA Astrophysics Data System (ADS)

McDaniel, S.; Gade, A.; Tostevin, J. A.; Baugher, T.; Bazin, D.; Brown, B. A.; Cook, J. M.; Glasmacher, T.; Grinyer, G. F.; Ratkiewicz, A.; Weisshaar, D.

2012-01-01

Background: Thick-target-induced nucleon-adding transfer reactions onto energetic rare-isotope beams are an emerging spectroscopic tool. Their sensitivity to single-particle structure complements one-nucleon removal reaction capabilities in the quest to reveal the evolution of nuclear shell structure in very exotic nuclei. Purpose: Our purpose is to add intermediate-energy, carbon-target-induced one-proton pickup reactions to the arsenal of γ-ray-tagged direct reactions applicable in the regime of low beam intensities and to apply these for the first time to fp-shell nuclei. Methods: Inclusive and partial cross sections were measured for the 12C(48Cr,49Mn+γ)X and 12C(50Fe,51Co+γ)X proton pickup reactions at 56.7 and 61.2 MeV/nucleon, respectively, using coincident particle-γ spectroscopy at the National Superconducting Cyclotron Laboratory. The results are compared to reaction theory calculations using fp-shell-model nuclear structure input. For comparison with our previous work, the same reactions were measured on 9Be targets. Results: The measured partial cross sections confirm the specific population pattern predicted by theory, with pickup into high-ℓ orbitals being strongly favored, driven by linear and angular momentum matching. Conclusion: Carbon-target-induced pickup reactions are well suited, in the regime of modest beam intensity, to study the evolution of nuclear structure, with specific sensitivities that are well described by theory.

Effect of structural heat conduction on the performance of micro-combustors and micro-thrusters

NASA Astrophysics Data System (ADS)

Leach, Timothy Thierry

This thesis investigates the effect of gas-structure interaction on the design and performance of miniaturized combustors with characteristic dimensions less than a few millimeters. These are termed 'micro-combustors' and are intended for use in devices ranging from micro-scale rocket motors for micro, nano, and pico-satellite propulsion, to micro-scale engines for micro-Unmanned Air Vehicle (UAV) propulsion and compact power generation. Analytical models for the propagation of a premixed laminar flame in a micro-channel are developed. The models' predictions are compared to the results of more detailed numerical simulations that incorporate multi-step chemistry, distributed heat transfer between the reacting gas and the combustor structure, heat transfer between the combustor and the environment, and heat transfer within the combustor structure. The results of the modeling and simulation efforts are found to be in good qualitative agreement and demonstrate that the behavior of premixed laminar flames in micro-channels is governed by heat transfer within the combustor structure and heat loss to the environment. The key findings of this work are as follows: First, heat transfer through the micro-combustor's structure tends to increase the flame speed and flame thickness. The increase in flame thickness with decreasing passage height suggests that micro-scale combustors will need to be longer than their conventional-scale counterparts. However, the increase in flame speed more than compensates for this effect and the net effect is that miniaturizing a combustor can increase its power density substantially. Second, miniaturizing chemical rocket thrusters can substantially increase thrust/weight ratio but comes at the price of reduced specific impulse (i.e. overall efficiency). Third, heat transfer through the combustor's structure increases steady-state and transient flame stability. This means that micro-scale combustors will be more stable than their conventional-scale counterparts. Fourth and finally, the extended temperature profile associated with the broadened flame causes a different set of elementary reactions to dominate the operation of the overall reaction mechanism at the micro-scale. This suggests that new chemical mechanisms may need to be developed in order to accurately simulate combustion at small-scales. It also calls into question the efficacy of single-step mechanisms presently used by other researchers.

Effective Governance and Hospital Boards Revisited: Reflections on 25 Years of Research.

PubMed

Erwin, Cathleen O; Landry, Amy Yarbrough; Livingston, Avery C; Dias, Ashley

2018-01-01

This study reviews and synthesizes empirical research literature focusing on the relationship between boards of directors and organizational effectiveness of U.S. hospitals. The study examines literature published in scholarly journals during the period of 1991-2017. Fifty-one empirical articles were identified that met the study's inclusion criteria. A framework from the corporate governance and nonprofit governance literature is used to classify the articles according to level of analysis (individual actors, governing bodies, organizations, and networks, alliances and multiorganizational initiatives) and focus of research (formal structure and behavioral dynamics-including informal structures and processes). Results are discussed, emerging trends are identified, and recommendations are made for future research.

Principles for Sustainable Governance of the Oceans

PubMed

Costanza; Andrade; Antunes; den Belt M; Boersma; Boesch; Catarino; Hanna; Limburg; Low; Molitor; Pereira; Rayner; Santos; Wilson; Young

1998-07-10

Pressures being exerted on the ocean ecosystems through overfishing, pollution, and environmental and climate change are increasing. Six core principles are proposed to guide governance and use of ocean resources and to promote sustainability. Examples of governance structures that embody these principles are given.

Insight into the Selectivity of Isopropanol Conversion at Strontium Titanate (100) Surfaces: A Combination Kinetic and Spectroscopic Study

DOE Office of Scientific and Technical Information (OSTI.GOV)

Tan, Shuai; Grey, Matthew B.; Kidder, Michelle

This work aims to better understand the role of interfacial molecular structure that governs selectivity and activity in heterogeneous catalytic reactions. To address this, a comprehensive study of isopropanol conversion over an archetypal perovskite material, strontium titanate (SrTiO 3 or STO), was performed with an array of techniques sensitive to orthogonal aspects of the ensuing chemistry. Cubic-shape STO nanoparticles with only the (100) facet exposed were synthesized and used to study the ensemble kinetic conversion of isopropanol over the surfaces, which showed a remarkable selectivity to form acetone, with minor propylene products appearing at elevated temperatures. These results in combinationmore » with inelastic neutron scattering measurements provide not only new insight into the selectivity and overall activity of the catalysts but also low frequency vibrational signatures of the adsorbed and reacted species. To compliment these measurements, pristine thin films of STO (100) were synthesized and used in combination with vibrational sum frequency generation spectroscopy to extract the absolute molecular orientation of the adsorbed molecules at the interface. It was found that the isopropanol assumes an orientation where the -CH group points towards the STO surface; this pre-reaction geometry offers an obvious pathway to produce acetone by abstracting the alpha-proton and, thus, provides a mechanistic explanation of selectivity at STO (100) surfaces. This new insight opens up pathways to explore and modify surfaces to tune the activity/selectivity though a molecular level understanding of the reactions at the surface.« less

Insight into the Selectivity of Isopropanol Conversion at Strontium Titanate (100) Surfaces: A Combination Kinetic and Spectroscopic Study

DOE PAGES

Tan, Shuai; Grey, Matthew B.; Kidder, Michelle; ...

2017-10-13

This work aims to better understand the role of interfacial molecular structure that governs selectivity and activity in heterogeneous catalytic reactions. To address this, a comprehensive study of isopropanol conversion over an archetypal perovskite material, strontium titanate (SrTiO 3 or STO), was performed with an array of techniques sensitive to orthogonal aspects of the ensuing chemistry. Cubic-shape STO nanoparticles with only the (100) facet exposed were synthesized and used to study the ensemble kinetic conversion of isopropanol over the surfaces, which showed a remarkable selectivity to form acetone, with minor propylene products appearing at elevated temperatures. These results in combinationmore » with inelastic neutron scattering measurements provide not only new insight into the selectivity and overall activity of the catalysts but also low frequency vibrational signatures of the adsorbed and reacted species. To compliment these measurements, pristine thin films of STO (100) were synthesized and used in combination with vibrational sum frequency generation spectroscopy to extract the absolute molecular orientation of the adsorbed molecules at the interface. It was found that the isopropanol assumes an orientation where the -CH group points towards the STO surface; this pre-reaction geometry offers an obvious pathway to produce acetone by abstracting the alpha-proton and, thus, provides a mechanistic explanation of selectivity at STO (100) surfaces. This new insight opens up pathways to explore and modify surfaces to tune the activity/selectivity though a molecular level understanding of the reactions at the surface.« less

Government management of two media-facilitated crises involving dioxin contamination of food.

PubMed

Jacob, Casey J; Lok, Corie; Morley, Katija; Powell, Douglas A

2011-03-01

Incidents become crises through a constant and intense public scrutiny facilitated by the media. Two incidents involving dioxin contamination of food led to crises in Belgium and the Republic of Ireland in 1999 and 2008, respectively. Thought to cause cancer in humans, dioxins reached the food supply in both incidents through the contamination of fat used for animal feed. The food and agricultural industries connected to each incident relied on crisis management activities of federal governments to limit adverse public reaction. Analysis of the management of the two crises by their respective federal governments, and a subsequent review of crisis management literature, led to the development of an effective crisis management model. Such a model, appropriately employed, may insulate industries associated with a crisis against damaged reputations and financial loss.

School Governance Structures that Foster Friendship in the Elementary School.

ERIC Educational Resources Information Center

Kuhmerker, Lisa

1989-01-01

Uses examples from the Schaefer School in Tappan (New York) to illustrate how an elementary school can develop an educational climate that fosters friendship, the key to student socialization. Discusses the following areas: (1) classroom activities; (2) school-wide democratic governance structures; (3) support staff roles; and (4) time scheduling.…

48 CFR 52.227-1 - Authorization and Consent.

Code of Federal Regulations, 2011 CFR

2011-10-01

... United States patent— (1) Embodied in the structure or composition of any article the delivery of which... a government regulatory body, of any invention described in and covered by a United States patent (1) embodied in the structure or composition of any article the delivery of which is accepted by the Government...

48 CFR 52.227-1 - Authorization and Consent.

Code of Federal Regulations, 2010 CFR

2010-10-01

... United States patent— (1) Embodied in the structure or composition of any article the delivery of which... a government regulatory body, of any invention described in and covered by a United States patent (1) embodied in the structure or composition of any article the delivery of which is accepted by the Government...

Program Administration | Division of Cancer Prevention

Cancer.gov

Governance Structure Recognizing the importance of an integrated approach to preventative drug development, there is a unified Governance Structure for the PREVENT Program responsible for coordinating and integrating available resources. With the goal of reaching go/no-go decisions as efficiently as possible, the purpose is to ensure a pragmatic approach to drug development

Roles and Structures for Participation in Higher Education Governance: A Rationale.

ERIC Educational Resources Information Center

Ikenberry, Stanley O.

It is obvious that the roles for participation of faculty, students and administrators in campus governance are inadequately defined and that the organizational structure through which these roles might be performed is deficient. This paper considers the rationale for such faculty and student organizations and examines some issues that have to be…

The 1993 Utah Legislative Session: Policy Implications for Educational Structure and Governance.

ERIC Educational Resources Information Center

Johnson, Bob L., Jr.; Sperry, David J.

This paper presents an overview and description of "significant" education legislation passed during the 1993 Utah Legislative Session. Specific attention is given to legislation that affects the governance and structure of education in the state. The centerpiece of the Governor's educational agenda and the definitive action of the 1993…

CEFPI's Heart to Honduras Educational Facilities Team.

ERIC Educational Resources Information Center

Jennings, James E.

1997-01-01

Describes efforts by the Council of Educational Facility Planners International to evaluate and modernize poor, rural schools in Honduras. A positive reaction to the visitation by government officials and teachers is revealed leading to the planned use of a model school program to guide school transformation. (GR)

A Case Study of Curriculum Implementation in Hong Kong.

ERIC Educational Resources Information Center

Carless, David R.

1998-01-01

Describes and analyzes the perceptions and reactions of a well-qualified, positively oriented primary-school English teacher to Hong Kong's target-oriented curriculum (TOC) initiative, a major government-sponsored innovation. The analysis encompasses teacher attitudes, teacher training and support, teachers' understanding of an innovation, teacher…

The anatomy of group dysfunction.

PubMed

Hayes, David F

2014-04-01

The dysfunction of the radiology group has 2 components: (1) the thinking component-the governance structure of the radiology group; how we manage the group; and (2) the structural component-the group's business model and its conflict with the partner's personal business model. Of the 2 components, governance is more important. Governance must be structured on classic, immutable business management principles. The structural component, the business model, is not immutable. In fact, it must continually change in response to the marketplace. Changes in the business model should occur only if demanded or permitted by the marketplace; instituting changes for other reasons, including personal interests or deficient knowledge of the deciders, is fundamentally contrary to the long-term interests of the group and its owners. First, we must learn basic business management concepts to appreciate the function and necessity of standard business models and standard business governance. Peter Drucker's The Effective Executive is an excellent primer on the subjects of standard business practices and the importance of a functional, authorized, and fully accountable chief executive officer. Copyright © 2014 American College of Radiology. Published by Elsevier Inc. All rights reserved.

Solution and solid state NMR approaches to draw iron pathways in the ferritin nanocage.

PubMed

Lalli, Daniela; Turano, Paola

2013-11-19

Ferritins are intracellular proteins that can store thousands of iron(III) ions as a solid mineral. These structures autoassemble from four-helix bundle subunits to form a hollow sphere and are a prototypical example of protein nanocages. The protein acts as a reservoir, encapsulating iron as ferric oxide in its central cavity in a nontoxic and bioavailable form. Scientists have long known the structural details of the protein shell, owing to very high resolution X-ray structures of the apoform. However, the atomic level mechanism governing the multistep biomineralization process remained largely elusive. Through analysis of the chemical behavior of ferritin mutants, chemists have found the role of some residues in key reaction steps. Using Mössbauer and XAS, they have identified some di-iron intermediates of the catalytic reaction trapped by rapid freeze quench. However, structural information about the iron interaction sites remains scarce. The entire process is governed by a number of specific, but weak, interactions between the protein shell and the iron species moving across the cage. While this situation may constitute a major problem for crystallography, NMR spectroscopy represents an optimal tool to detect and characterize transient species involving soluble proteins. Regardless, NMR analysis of the 480 kDa ferritin represents a real challenge. Our interest in ferritin chemistry inspired us to use an original combination of solution and solid state approaches. While the highly symmetric structure of the homo-24-mer frog ferritin greatly simplifies the spectra, the large protein size hinders the efficient coherence transfer in solution, thus preventing the sequence specific assignments. In contrast, extensive (13)C-spin diffusion makes the solution (13)C-(13)C NOESY experiment our gold standard to monitor protein side chains both in the apoprotein alone and in its interaction with paramagnetic iron species, inducing line broadening on the resonances of nearby residues. We could retrieve the structural information embedded in the (13)C-(13)C NOESY due to a partial sequence specific assignment of protein backbone and side chains we obtained from solid state MAS NMR of ferritin microcrystals. We used the 59 assigned amino acids (∼33% of the total) as probes to locate paramagnetic ferric species in the protein cage. Through this approach, we could identify ferric dimers at the ferroxidase site and on their pathway towards the nanocage. Comparison with existing data on bacterioferritins and bacterial ferritins, as well as with eukaryotic ferritins loaded with various nonfunctional divalent ions, allowed us to reinterpret the available information. The resulting picture of the ferroxidase site is slightly different with various ferritins but is designed to provide multiple and generally weak iron ligands. The latter assist binding of two incoming iron(II) ions in two proximal positions to facilitate coupling with oxygen. Subsequent oxidation is accompanied by a decrease in the metal-metal distance (consistent with XAS/Mössbauer) and in the number of protein residues involved in metal coordination, facilitating the release of products as di-iron clusters under the effect of new incoming iron(II) ions.

Ontology aided modeling of organic reaction mechanisms with flexible and fragment based XML markup procedures.

PubMed

Sankar, Punnaivanam; Aghila, Gnanasekaran

2007-01-01

The mechanism models for primary organic reactions encoding the structural fragments undergoing substitution, addition, elimination, and rearrangements are developed. In the proposed models, each and every structural component of mechanistic pathways is represented with flexible and fragment based markup technique in XML syntax. A significant feature of the system is the encoding of the electron movements along with the other components like charges, partial charges, half bonded species, lone pair electrons, free radicals, reaction arrows, etc. needed for a complete representation of reaction mechanism. The rendering of reaction schemes described with the proposed methodology is achieved with a concise XML extension language interoperating with the structure markup. The reaction scheme is visualized as 2D graphics in a browser by converting them into SVG documents enabling the desired layouts normally perceived by the chemists conventionally. An automatic representation of the complex patterns of the reaction mechanism is achieved by reusing the knowledge in chemical ontologies and developing artificial intelligence components in terms of axioms.

Ab initio quantum mechanical calculation of the reaction probability for the Cl-+PH2Cl→ClPH2+Cl- reaction

NASA Astrophysics Data System (ADS)

Farahani, Pooria; Lundberg, Marcus; Karlsson, Hans O.

2013-11-01

The SN2 substitution reactions at phosphorus play a key role in organic and biological processes. Quantum molecular dynamics simulations have been performed to study the prototype reaction Cl-+PH2Cl→ClPH2+Cl-, using one and two-dimensional models. A potential energy surface, showing an energy well for a transition complex, was generated using ab initio electronic structure calculations. The one-dimensional model is essentially reflection free, whereas the more realistic two-dimensional model displays involved resonance structures in the reaction probability. The reaction rate is almost two orders of magnitude smaller for the two-dimensional compared to the one-dimensional model. Energetic errors in the potential energy surface is estimated to affect the rate by only a factor of two. This shows that for these types of reactions it is more important to increase the dimensionality of the modeling than to increase the accuracy of the electronic structure calculation.

Strategic behaviors and governance challenges in social-ecological systems

NASA Astrophysics Data System (ADS)

Muneepeerakul, Rachata; Anderies, John M.

2017-08-01

The resource management and environmental policy literature focuses on devising regulations and incentive structures to achieve desirable goals. It often presumes the existence of public infrastructure that actualizes these incentives and regulations through a process loosely referred to as `governance.' In many cases, it is not clear if and how such governance infrastructure can be created and supported. Here, we take a complex systems view in which `governance' is an emergent phenomenon generated by interactions between social, economic, and environmental (both built and natural) factors. We present a framework and formal stylized model to explore under what circumstances stable governance structures may emerge endogenously in coupled infrastructure systems comprising shared natural, social, and built infrastructures of which social-ecological systems are specific examples. The model allows us to derive general conditions for a sustainable coupled infrastructure system in which critical infrastructure (e.g., canals) is provided by a governing entity that enables resource users (e.g., farmers) to produce outputs from natural infrastructure (e.g., water) to meet their needs while supporting the governing entity.

Workshop on Critical Issues in Microgravity Fluids, Transport, and Reaction Processes in Advanced Human Support Technology

NASA Technical Reports Server (NTRS)

Chiaramonte, Francis P.; Joshi, Jitendra A.

2004-01-01

This workshop was designed to bring the experts from the Advanced Human Support Technologies communities together to identify the most pressing and fruitful areas of research where success hinges on collaborative research between the two communities. Thus an effort was made to bring together experts in both advanced human support technologies and microgravity fluids, transport and reaction processes. Expertise was drawn from academia, national laboratories, and the federal government. The intent was to bring about a thorough exchange of ideas and develop recommendations to address the significant open design and operation issues for human support systems that are affected by fluid physics, transport and reaction processes. This report provides a summary of key discussions, findings, and recommendations.

The biochemical basis for thermoregulation in heat-producing flowers

PubMed Central

Umekawa, Yui; Seymour, Roger S.; Ito, Kikukatsu

2016-01-01

Thermoregulation (homeothermy) in animals involves a complex mechanism involving thermal receptors throughout the body and integration in the hypothalamus that controls shivering and non-shivering thermogenesis. The flowers of some ancient families of seed plants show a similar degree of physiological thermoregulation, but by a different mechanism. Here, we show that respiratory control in homeothermic spadices of skunk cabbage (Symplocarpus renifolius) is achieved by rate-determining biochemical reactions in which the overall thermodynamic activation energy exhibits a negative value. Moreover, NADPH production, catalyzed by mitochondrial isocitrate dehydrogenase in a chemically endothermic reaction, plays a role in the pre-equilibrium reaction. We propose that a law of chemical equilibrium known as Le Châtelier’s principle governs the homeothermic control in skunk cabbage. PMID:27095582

Probing the type of anomalous diffusion with single-particle tracking.

PubMed

Ernst, Dominique; Köhler, Jürgen; Weiss, Matthias

2014-05-07

Many reactions in complex fluids, e.g. signaling cascades in the cytoplasm of living cells, are governed by a diffusion-driven encounter of reactants. Yet, diffusion in complex fluids often exhibits an anomalous characteristic ('subdiffusion'). Since different types of subdiffusion have distinct effects on timing and equilibria of chemical reactions, a thorough determination of the reactants' type of random walk is key to a quantitative understanding of reactions in complex fluids. Here we introduce a straightforward and simple approach for determining the type of subdiffusion from single-particle tracking data. Unlike previous approaches, our method also is sensitive to transient subdiffusion phenomena, e.g. obstructed diffusion below the percolation threshold. We validate our strategy with data from experiment and simulation.

Security Cooperation Activities: Strengthening a Partner Military and its Governing Institutions

DTIC Science & Technology

2016-05-26

governments suffered from economic instability , corruption, poor rule of law, and low administration of justice. Government and economic stability ...types of programs applied. Conditions defining allied state characteristics are military structure, government polity rating, and economic stability ...regional instability . Dr. Michael Mihalka and Mr. Mark Wilcox covered the trends in liberal democracy in the South Caucasus in light of economic

Sustained Innovation Through Shared Capitalism and Democratic Governance

NASA Astrophysics Data System (ADS)

Beyster, M. A.; Blasi, J.; Sibilia, J.; Zebuchen, T.; Bowman, A.

The Foundation for Enterprise Development (FED) explores application of democratic representative governance models and structures for long-term interdisciplinary research, development and education to the concept of an organization that can sustain activity in support of interstellar travel in the 100-year timeframe, as outlined by the 100 Year StarshipTM. This paper titled, Sustained Innovation through Shared Capitalism and Democratic Governance , explores the roots of representative structures and organizations as long-lived success stories throughout history. Research, innovation, organizational structures and associated issues are explored to address the long-term focus required for development, both material and human. Impact investing vehicles are also explored as potential investment structures addressing the long-term horizon required by the organization. This paper provides an illustration, description and philosophical approach of this model as developed by the FED and our collaborators.

Hydrolytic degradation of N,N‧-ethylenedimaleimide: Crystal structures of key intermediates and proposed mechanisms

NASA Astrophysics Data System (ADS)

Tan, Xue-Jie; Cheng, Shuang-Shuang; Shi, Yan; Xing, Dian-Xiang; Liu, Yun; Li, Hui; Feng, Wen-Quan; Yang, Jian-Bo

2016-12-01

Maleimide groups are used extensively in bioconjugation reactions, but limited mechanistic studies are available regarding their hydrolysis reactions. In this paper, five single-crystal structures related with the reaction of four-step hydrolytic degradation of N,N‧-ethylenedimaleimide have been investigated. On the basis of experimental results, the reaction mechanisms without or with water catalysis are proposed, which could provide some enlightenment into the study of similar hydrolytic degradations.

Catalytic reactor

DOEpatents

Aaron, Timothy Mark [East Amherst, NY; Shah, Minish Mahendra [East Amherst, NY; Jibb, Richard John [Amherst, NY

2009-03-10

A catalytic reactor is provided with one or more reaction zones each formed of set(s) of reaction tubes containing a catalyst to promote chemical reaction within a feed stream. The reaction tubes are of helical configuration and are arranged in a substantially coaxial relationship to form a coil-like structure. Heat exchangers and steam generators can be formed by similar tube arrangements. In such manner, the reaction zone(s) and hence, the reactor is compact and the pressure drop through components is minimized. The resultant compact form has improved heat transfer characteristics and is far easier to thermally insulate than prior art compact reactor designs. Various chemical reactions are contemplated within such coil-like structures such that as steam methane reforming followed by water-gas shift. The coil-like structures can be housed within annular chambers of a cylindrical housing that also provide flow paths for various heat exchange fluids to heat and cool components.

Nursing domain of CI governance: recommendations for health IT adoption and optimization.

PubMed

Collins, Sarah A; Alexander, Dana; Moss, Jacqueline

2015-05-01

There is a lack of recommended models for clinical informatics (CI) governance that can facilitate successful health information technology implementation. To understand existing CI governance structures and provide a model with recommended roles, partnerships, and councils based on perspectives of nursing informatics leaders. We conducted a cross-sectional study through administering a survey via telephone to facilitate semistructured interviews from June 2012 through November 2012. We interviewed 12 nursing informatics leaders, across the United States, currently serving in executive- or director-level CI roles at integrated health care systems that have pioneered electronic health records implementation projects. We found the following 4 themes emerge: (1) Interprofessional partnerships are essential. (2) Critical role-based levels of practice and competencies need to be defined. (3) Integration into existing clinical infrastructure facilitates success. (4) CI governance is an evolving process. We described specific lessons learned and a model of CI governance with recommended roles, partnerships, and councils from the perspective of nursing informatics leaders. Applied CI work is highly interprofessional with patient safety implications that heighten the need for best practice models for governance structures, adequate resource allocation, and role-based competencies. Overall, there is a notable lack of a centralized CI group comprised of formally trained informaticians to provide expertise and promote adherence to informatics principles within EHR implementation governance structures. Our model of the nursing domain of CI governance with recommended roles, partnerships, and councils provides a starting point that should be further explored and validated. Not only can the model be used to understand, shape, and standardize roles, competencies, and structures within CI practice for nursing, it can be used within other clinical domains and by other informaticians. © The Author 2015. Published by Oxford University Press on behalf of the American Medical Informatics Association. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

Balancing stability and flexibility in adaptive governance: An analysis of tools available in U.S. environmental law

USGS Publications Warehouse

Kundis Craig, Robin; Garmestani, Ahjond S.; Allen, Craig R.; Arnold, Craig Anthony (Tony); Birge, Hannah E.; DeCaro, Daniel A.; Fremier, Alexander K.; Gosnell, Hannah; Schlager, Edella

2017-01-01

Adaptive governance must work “on the ground,” that is, it must operate through structures and procedures that the people it governs perceive to be legitimate and fair, as well as incorporating processes and substantive goals that are effective in allowing social-ecological systems (SESs) to adapt to climate change and other impacts. To address the continuing and accelerating alterations that climate change is bringing to SESs, adaptive governance generally will require more flexibility than prior governance institutions have often allowed. However, to function as good governance, adaptive governance must pay real attention to the problem of how to balance this increased need for flexibility with continuing governance stability so that it can foster adaptation to change without being perceived or experienced as perpetually destabilizing, disruptive, and unfair. Flexibility and stability serve different purposes in governance, and a variety of tools exist to strike different balances between them while still preserving the governance institution’s legitimacy among the people governed. After reviewing those purposes and the implications of climate change for environmental governance, we examine psychological insights into the structuring of adaptive governance and the variety of legal tools available to incorporate those insights into adaptive governance regimes. Because the substantive goals of governance systems will differ among specific systems, we do not purport to comment on what the normative or substantive goals of law should be. Instead, we conclude that attention to process and procedure (including participation), as well as increased use of substantive standards (instead of rules), may allow an increased level of substantive flexibility to operate with legitimacy and fairness, providing the requisite levels of psychological, social, and economic stability needed for communities to adapt successfully to the Anthropocene.

Balancing stability and flexibility in adaptive governance: an analysis of tools available in U.S. environmental law.

PubMed

Craig, Robin Kundis; Garmestani, Ahjond S; Allen, Craig R; Arnold, Craig Anthony Tony; Birgé, Hannah; DeCaro, Daniel A; Fremier, Alexander K; Gosnell, Hannah; Schlager, Edella

2017-06-30

Adaptive governance must work "on the ground," that is, it must operate through structures and procedures that the people it governs perceive to be legitimate and fair, as well as incorporating processes and substantive goals that are effective in allowing social-ecological systems (SESs) to adapt to climate change and other impacts. To address the continuing and accelerating alterations that climate change is bringing to SESs, adaptive governance generally will require more flexibility than prior governance institutions have often allowed. However, to function as good governance, adaptive governance must pay real attention to the problem of how to balance this increased need for flexibility with continuing governance stability so that it can foster adaptation to change without being perceived or experienced as perpetually destabilizing, disruptive, and unfair. Flexibility and stability serve different purposes in governance, and a variety of tools exist to strike different balances between them while still preserving the governance institution's legitimacy among the people governed. After reviewing those purposes and the implications of climate change for environmental governance, we examine psychological insights into the structuring of adaptive governance and the variety of legal tools available to incorporate those insights into adaptive governance regimes. Because the substantive goals of governance systems will differ among specific systems, we do not purport to comment on what the normative or substantive goals of law should be. Instead, we conclude that attention to process and procedure (including participation), as well as increased use of substantive standards (instead of rules), may allow an increased level of substantive flexibility to operate with legitimacy and fairness, providing the requisite levels of psychological, social, and economic stability needed for communities to adapt successfully to the Anthropocene.

45 CFR 1304.50 - Program governance.

Code of Federal Regulations, 2013 CFR

2013-10-01

... AGENCIES Program Design and Management § 1304.50 Program governance. (a) Policy Council, Policy Committee... about the program. This structure must consist of the following groups, as required: (i) Policy Council... Council. (5) The governing body (the group with legal and fiscal responsibility for administering the...

Searching LOGIN, the Local Government Information Network.

ERIC Educational Resources Information Center

Jack, Robert F.

1984-01-01

Describes a computer-based information retrieval and electronic messaging system produced by Control Data Corporation now being used by government agencies and other organizations. Background of Local Government Information Network (LOGIN), database structure, types of LOGIN units, searching LOGIN (intersect, display, and list commands), and how…

CONSIDERATION OF REACTION INTERMEDIATES IN STRUCTURE-ACTIVITY RELATIONSHIPS: A KEY TO UNDERSTANDING AND PREDICTION

EPA Science Inventory

Consideration of Reaction Intermediates in Structure- Activity Relationships: A Key to Understanding and Prediction

A structure-activity relationship (SAR) represents an empirical means for generalizing chemical information relative to biological activity, and is frequent...

National Nuclear Data Center

Science.gov Websites

reaction data Sigma Retrieval & Plotting Nuclear structure & decay Data Nuclear Science References Experimental Unevaluated Nuclear Data List Evaluated Nuclear Structure Data File NNDC databases Ground and isomeric states properties Nuclear structure & decay data journal Nuclear reaction model code Tools and

Do governance choices matter in health care networks?: an exploratory configuration study of health care networks

PubMed Central

2013-01-01

Background Health care networks are widely used and accepted as an organizational form that enables integrated care as well as dealing with complex matters in health care. However, research on the governance of health care networks lags behind. The research aim of our study is to explore the type and importance of governance structure and governance mechanisms for network effectiveness. Methods The study has a multiple case study design and covers 22 health care networks. Using a configuration view, combinations of network governance and other network characteristics were studied on the level of the network. Based on interview and questionnaire data, network characteristics were identified and patterns in the data looked for. Results Neither a dominant (or optimal) governance structure or mechanism nor a perfect fit among governance and other characteristics were revealed, but a number of characteristics that need further study might be related to effective networks such as the role of governmental agencies, legitimacy, and relational, hierarchical, and contractual governance mechanisms as complementary factors. Conclusions Although the results emphasize the situational character of network governance and effectiveness, they give practitioners in the health care sector indications of which factors might be more or less crucial for network effectiveness. PMID:23800334

Hall effects on unsteady MHD reactive flow of second grade fluid through porous medium in a rotating parallel plate channel

NASA Astrophysics Data System (ADS)

Krishna, M. Veera; Swarnalathamma, B. V.

2017-07-01

We considered the transient MHD flow of a reactive second grade fluid through porous medium between two infinitely long horizontal parallel plates when one of the plate is set into uniform accelerated motion in the presence of a uniform transverse magnetic field under Arrhenius reaction rate. The governing equations are solved by Laplace transform technique. The effects of the pertinent parameters on the velocity, temperature are discussed in detail. The shear stress and Nusselt number at the plates are also obtained analytically and computationally discussed with reference to governing parameters.

Computational Exploration of the Li-Electrode|Electrolyte Interface in the Presence of a Nanometer Thick Solid-Electrolyte Interphase Layer [Computational exploration of the Li-electrode|electrolyte interface complicated by a nanometer thin solid-electrolyte interphase (SEI) layer

DOE PAGES

Li, Yunsong; Leung, Kevin; Qi, Yue

2016-09-30

A nanometer thick passivation layer will spontaneously form on Li-metal in battery applications due to electrolyte reduction reactions. This passivation layer in rechargeable batteries must have “selective” transport properties: blocking electrons from attacking the electrolytes, while allowing Li + ion to pass through so the electrochemical reactions can continue. The classical description of the electrochemical reaction, Li + + e → Li 0, occurring at the Li-metal|electrolyte interface is now complicated by the passivation layer and will reply on the coupling of electronic and ionic degrees of freedom in the layer. We consider the passivation layer, called “solid electrolyte interphasemore » (SEI)”, as “the most important but the least understood in rechargeable Li-ion batteries,” partly due to the lack of understanding of its structure–property relationship. In predictive modeling, starting from the ab initio level, we find that it is an important tool to understand the nanoscale processes and materials properties governing the interfacial charge transfer reaction at the Li-metal|SEI|electrolyte interface. Here, we demonstrate pristine Li-metal surfaces indeed dissolve in organic carbonate electrolytes without the SEI layer. Based on joint modeling and experimental results, we point out that the well-known two-layer structure of SEI also exhibits two different Li + ion transport mechanisms. The SEI has a porous (organic) outer layer permeable to both Li + and anions (dissolved in electrolyte), and a dense (inorganic) inner layer facilitate only Li + transport. This two-layer/two-mechanism diffusion model suggests only the dense inorganic layer is effective at protecting Li-metal in electrolytes. This model suggests a strategy to deconvolute the structure–property relationships of the SEI by analyzing an idealized SEI composed of major components, such as Li 2CO 3, LiF, Li 2O, and their mixtures. After sorting out the Li+ ion diffusion carriers and their diffusion pathways, we design methods to accelerate the Li + ion conductivity by doping and by using heterogonous structure designs. We will predict the electron tunneling barriers and connect them with measurable first cycle irreversible capacity loss. We note that the SEI not only affects Li + and e – transport, but it can also impose a potential drop near the Li-metal|SEI interface. Our challenge is to fully describe the electrochemical reactions at the Li -metal|SEI|electrolyte interface. This will be the subject of ongoing efforts.« less

Computational Exploration of the Li-Electrode|Electrolyte Interface in the Presence of a Nanometer Thick Solid-Electrolyte Interphase Layer [Computational exploration of the Li-electrode|electrolyte interface complicated by a nanometer thin solid-electrolyte interphase (SEI) layer

DOE Office of Scientific and Technical Information (OSTI.GOV)

Li, Yunsong; Leung, Kevin; Qi, Yue

A nanometer thick passivation layer will spontaneously form on Li-metal in battery applications due to electrolyte reduction reactions. This passivation layer in rechargeable batteries must have “selective” transport properties: blocking electrons from attacking the electrolytes, while allowing Li + ion to pass through so the electrochemical reactions can continue. The classical description of the electrochemical reaction, Li + + e → Li 0, occurring at the Li-metal|electrolyte interface is now complicated by the passivation layer and will reply on the coupling of electronic and ionic degrees of freedom in the layer. We consider the passivation layer, called “solid electrolyte interphasemore » (SEI)”, as “the most important but the least understood in rechargeable Li-ion batteries,” partly due to the lack of understanding of its structure–property relationship. In predictive modeling, starting from the ab initio level, we find that it is an important tool to understand the nanoscale processes and materials properties governing the interfacial charge transfer reaction at the Li-metal|SEI|electrolyte interface. Here, we demonstrate pristine Li-metal surfaces indeed dissolve in organic carbonate electrolytes without the SEI layer. Based on joint modeling and experimental results, we point out that the well-known two-layer structure of SEI also exhibits two different Li + ion transport mechanisms. The SEI has a porous (organic) outer layer permeable to both Li + and anions (dissolved in electrolyte), and a dense (inorganic) inner layer facilitate only Li + transport. This two-layer/two-mechanism diffusion model suggests only the dense inorganic layer is effective at protecting Li-metal in electrolytes. This model suggests a strategy to deconvolute the structure–property relationships of the SEI by analyzing an idealized SEI composed of major components, such as Li 2CO 3, LiF, Li 2O, and their mixtures. After sorting out the Li+ ion diffusion carriers and their diffusion pathways, we design methods to accelerate the Li + ion conductivity by doping and by using heterogonous structure designs. We will predict the electron tunneling barriers and connect them with measurable first cycle irreversible capacity loss. We note that the SEI not only affects Li + and e – transport, but it can also impose a potential drop near the Li-metal|SEI interface. Our challenge is to fully describe the electrochemical reactions at the Li -metal|SEI|electrolyte interface. This will be the subject of ongoing efforts.« less

Hybrid discrete/continuum algorithms for stochastic reaction networks

DOE PAGES

Safta, Cosmin; Sargsyan, Khachik; Debusschere, Bert; ...

2014-10-22

Direct solutions of the Chemical Master Equation (CME) governing Stochastic Reaction Networks (SRNs) are generally prohibitively expensive due to excessive numbers of possible discrete states in such systems. To enhance computational efficiency we develop a hybrid approach where the evolution of states with low molecule counts is treated with the discrete CME model while that of states with large molecule counts is modeled by the continuum Fokker-Planck equation. The Fokker-Planck equation is discretized using a 2nd order finite volume approach with appropriate treatment of flux components to avoid negative probability values. The numerical construction at the interface between the discretemore » and continuum regions implements the transfer of probability reaction by reaction according to the stoichiometry of the system. As a result, the performance of this novel hybrid approach is explored for a two-species circadian model with computational efficiency gains of about one order of magnitude.« less

Essential chemistry for biochemists

PubMed Central

Jonsson, Amanda L.; Roberts, Mark A.J.; Kiappes, J.L.; Scott, Kathryn A.

2017-01-01

Within every living organism, countless reactions occur every second. These reactions typically occur more rapidly and with greater efficiency than would be possible under the same conditions in the chemical laboratory, and while using only the subset of elements that are readily available in nature. Despite these apparent differences between life and the laboratory, biological reactions are governed by the same rules as any other chemical reaction. Thus, a firm understanding of the fundamentals of chemistry is invaluable in biochemistry. There are entire textbooks devoted to the application of chemical principles in biological systems and so it is not possible to cover all of the relevant topics in depth in this short article. The aim is instead to provide a brief overview of those areas in chemistry that are most relevant to biochemistry. We summarize the basic principles, give examples of how these principles are applied in biological systems and suggest further reading on individual topics. PMID:28951470

Pion-photon reactions and chiral dynamics in Primakoff processes at COMPASS

DOE Office of Scientific and Technical Information (OSTI.GOV)

Friedrich, Jan Michael

2016-01-22

With the COMPASS experiment at CERN, pion-photon reactions are investigated via the Primakoff effect, implying that high-energetic pions react with the quasi-real photon field surrounding the target nuclei. The production of a single hard photon in such a pion scattering at lowest momentum transfer to the nucleus is related to pion Compton scattering. From the measured cross-section shape, the pion polarisability is determined. The COMPASS measurement is in contradiction to the earlier dedicated measurements, and rather in agreement with the theoretical expectation from chiral perturbation theory. In the same data taking, reactions with neutral and charged pions in the finalmore » state are measured and analyzed. At low energy in the pion-photon centre-of-momentum system, these reactions are governed by chiral dynamics and contain information relevant for chiral perturbation theory. At higher energies, resonances are produced and their radiative coupling is investigated.« less

Discovering the electronic circuit diagram of life: structural relationships among transition metal binding sites in oxidoreductases

PubMed Central

Kim, J. Dongun; Senn, Stefan; Harel, Arye; Jelen, Benjamin I.; Falkowski, Paul G.

2013-01-01

Oxidoreductases play a central role in catalysing enzymatic electron-transfer reactions across the tree of life. To first order, the equilibrium thermodynamic properties of these proteins are governed by protein folds associated with specific transition metals and ligands at the active site. A global analysis of holoenzyme structures and functions suggests that there are fewer than approximately 500 fundamental oxidoreductases, which can be further clustered into 35 unique groups. These catalysts evolved in prokaryotes early in the Earth's history and are largely responsible for the emergence of non-equilibrium biogeochemical cycles on the planet's surface. Although the evolutionary history of the amino acid sequences in the oxidoreductases is very difficult to reconstruct due to gene duplication and horizontal gene transfer, the evolution of the folds in the catalytic sites can potentially be used to infer the history of these enzymes. Using a novel, yet simple analysis of the secondary structures associated with the ligands in oxidoreductases, we developed a structural phylogeny of these enzymes. The results of this ‘composome’ analysis suggest an early split from a basal set of a small group of proteins dominated by loop structures into two families of oxidoreductases, one dominated by α-helices and the second by β-sheets. The structural evolutionary patterns in both clades trace redox gradients and increased hydrogen bond energy in the active sites. The overall pattern suggests that the evolution of the oxidoreductases led to decreased entropy in the transition metal folds over approximately 2.5 billion years, allowing the enzymes to use increasingly oxidized substrates with high specificity. PMID:23754810

Experimental collaboration for thick concrete structures with alkali-silica reaction

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ezell, N Dianne Bull; Hayes, Nolan W.; Lenarduzzi, Roberto

Alkali-Silica Reaction (ASR) is a reaction that occurs over time in concrete between alkaline cement paste and reactive, non-crystalline silica in aggregates. An expansive gel is formed within the aggregates which results in micro-cracks in aggregates and adjacent cement paste. The reaction requires the presence of water and has been predominantly detected in groundwater-impacted portions of below grade structures, with limited impact to exterior surfaces in above grade structures. ASR can potentially affect concrete properties and performance characteristics such as compressive strength, modulus of elasticity, shear strength, and tensile strength. Since ASR degradation often takes significant amounts of time, developingmore » ASR detection techniques is important to the sustainability and extended operation lifetimes of nuclear power plants (NPPs). The University of Tennessee, Knoxville (UTK) in collaboration with Oak Ridge National Laboratory (ORNL) designed and built an experiment representative of typical NPP structures to study ASR in thick concrete structures.« less

Experimental collaboration for thick concrete structures with alkali-silica reaction

NASA Astrophysics Data System (ADS)

Ezell, N. Dianne Bull; Hayes, Nolan; Lenarduzzi, Roberto; Clayton, Dwight; Ma, Z. John; Le Pape, Sihem; Le Pape, Yann

2018-04-01

Alkali-Silica Reaction (ASR) is a reaction that occurs over time in concrete between alkaline cement paste and reactive, non-crystalline silica in aggregates. An expansive gel is formed within the aggregates which results in micro-cracks in aggregates and adjacent cement paste. The reaction requires the presence of water and has been predominantly detected in groundwater-impacted portions of below grade structures, with limited impact to exterior surfaces in above grade structures. ASR can potentially affect concrete properties and performance characteristics such as compressive strength, modulus of elasticity, shear strength, and tensile strength. Since ASR degradation often takes significant amounts of time, developing ASR detection techniques is important to the sustainability and extended operation lifetimes of nuclear power plants (NPPs). The University of Tennessee, Knoxville (UTK) in collaboration with Oak Ridge National Laboratory (ORNL) designed and built an experiment representative of typical NPP structures to study ASR in thick concrete structures.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Barker, J. Jr.; Tenenbaum, B.; Woolf, F.

This paper focuses on the governance and regulation of power pools outside the United States. The current governance and regulatory arrangements for four power pools, as developed in pool documents and government regulations and laws, are compared and contrasted. The power pools analyzed are located in England and Wales, Australia, Canada, and Scandinavia. Topics discussed in relation to these pools are the effects of structure on governance, how each pool has dealt with a number of basic governance decisions, how the pools monitor the markets, ways in which regulators and other institutions control pools, and self-governance issues.

Due Process in Appraisal: A Quasi-Experiment in Procedural Justice.

ERIC Educational Resources Information Center

Taylor, M. Susan; And Others

1995-01-01

Extended research on procedural justice by examining effects of a due-process performance-appraisal system on (government) employees' and managers' reactions. Employee-management pairs were randomly assigned to either a due-process appraisal system or the existing one. Although due-process employees received lower evaluations, both employees and…

New Zealand Free Kindergartens: Free or Freely Forgotten?

ERIC Educational Resources Information Center

Duncan, Judith

2007-01-01

Since the 1980s in New Zealand, the kindergarten service, once called the "flagship" within early childhood education, has changed in reaction to the need for "diversity" and "responsiveness" to its communities and restructured government requirements. This paper draws on life-history interviews with a small group of…

The World Conservation Strategy and Environmental Education.

ERIC Educational Resources Information Center

Nature Conservation Education Committee, Rijswijk (Netherlands).

On March 5, 1980, the "World Conservation Strategy: Living Resource Conservation for Sustainable Development" (WCS) report was submitted to the Dutch government. The Nature Conservation Education Committee (CNBE) was then asked to prepare another report based on its initial reactions to the WCS, particularly to section 13, which deals…

Proposition 2 1/2: Explaining the Vote.

ERIC Educational Resources Information Center

Ladd, Helen F.; Wilson, Julie Boatright

Researchers examined Massachusetts voters' reactions to Proposition 2 1/2--which severely restricts local governments' ability to raise money for local public services--through a statewide telephone survey of 1,561 household heads in 58 towns. Data were gathered on each respondent's vote on the proposition, sex, age, education, occupation, income,…

Analytical solution for multi-species contaminant transport in finite media with time-varying boundary conditions

USDA-ARS?s Scientific Manuscript database

Most analytical solutions available for the equations governing the advective-dispersive transport of multiple solutes undergoing sequential first-order decay reactions have been developed for infinite or semi-infinite spatial domains and steady-state boundary conditions. In this work we present an ...

The Politics of Childhood and Asylum in the UK

ERIC Educational Resources Information Center

Giner, Clotilde

2007-01-01

This article considers the general treatment of asylum-seeking families with children in the UK, focusing on the government's practices and public reactions to these measures. It first describes both the exclusive asylum framework, based on institutionalised suspicion, welfare restrictions and detention, and the inclusive child policy framework,…

2012: A Brave New World

ERIC Educational Resources Information Center

Jeffreys, Andrea

2012-01-01

The Australian Government decision in response to the Bradley review to introduce a demand-driven funding model for undergraduate university places from 2012 was met with mixed reaction across the higher education sector. The removal of caps without subsequent fee deregulation is considered by some to be unsustainable. Opinions suggest that…

Guinea’s New Transitional Government: Emerging Issues for U.S. Policy

DTIC Science & Technology

2010-04-23

seat after the 2002 legislative elections in a protest against electoral fraud .10 U.S. and Other International Reactions U.S. officials have...Correction des Listes Electorales Provisoires: la CENI sur la sellette - 87000 électeurs disparus des listes à Siguiri - quasi inexistence des listes

Escape from Albuquerque: An Apache Memorate.

ERIC Educational Resources Information Center

Greenfeld, Philip J.

2001-01-01

Clarence Hawkins, a White Mountain Apache, escaped from the Albuquerque Indian School around 1920. His 300-mile trip home, made with two other boys, exemplifies the reaction of many Indian youths to the American government's plans for cultural assimilation. The tale is told in the form of traditional Apache narrative. (TD)

Electrochemistry and the mechanisms of nucleation and growth of neodymium during electroreduction from LiCl-KCl eutectic salts on Mo substrate

NASA Astrophysics Data System (ADS)

Tang, Hao; Pesic, Batric

2015-03-01

The electrochemical behavior of NdCl3 was studied on a Mo electrode in molten LiCl-KCl eutectic salts. The electroreduction of Nd(III)/Nd(0) involved two reaction steps, as confirmed by three different electrochemical techniques. In the first reaction step, Nd(III) is converted into soluble Nd(II), which undergoes further reduction into metallic Nd(0) in the second reaction step. The standard reaction rate constants for each reaction step were determined by Nicholson method. The rate constant values were used in Matsuda-Ayabe's criteria for testing the electrochemical reversibility. Accordingly, both reaction steps were quasi-reversible redox reactions. The nucleation mechanisms of neodymium metal deposited on a Mo substrate were predicted by using Scharifker-Hill model, and tested for the first time by scanning electron microscopy (SEM) studies of the electrode surface. The SEM studies confirmed that for the low initial concentration of NdCl3, neodymium nucleates and grows progressively, while for higher NdCl3 concentrations, the related mechanism is instantaneous. Both are governed by the aggregative growth mechanisms based on surface mobility of formed nanoclusters.

A thermodynamic framework for thermo-chemo-elastic interactions in chemically active materials

NASA Astrophysics Data System (ADS)

Zhang, XiaoLong; Zhong, Zheng

2017-08-01

In this paper, a general thermodynamic framework is developed to describe the thermo-chemo-mechanical interactions in elastic solids undergoing mechanical deformation, imbibition of diffusive chemical species, chemical reactions and heat exchanges. Fully coupled constitutive relations and evolving laws for irreversible fluxes are provided based on entropy imbalance and stoichiometry that governs reactions. The framework manifests itself with a special feature that the change of Helmholtz free energy is attributed to separate contributions of the diffusion-swelling process and chemical reaction-dilation process. Both the extent of reaction and the concentrations of diffusive species are taken as independent state variables, which describe the reaction-activated responses with underlying variation of microstructures and properties of a material in an explicit way. A specialized isothermal formulation for isotropic materials is proposed that can properly account for volumetric constraints from material incompressibility under chemo-mechanical loadings, in which inhomogeneous deformation is associated with reaction and diffusion under various kinetic time scales. This framework can be easily applied to model the transient volumetric swelling of a solid caused by imbibition of external chemical species and simultaneous chemical dilation arising from reactions between the diffusing species and the solid.

Business-Government Relations in Canadian History.

ERIC Educational Resources Information Center

Traves, Tom

1982-01-01

The history of government intervention in Canada's economy from the nineteenth century through the Depression and the two world wars can be divided into two periods. Approaches to analysis of business-government relations focus on cultural and ideological origins of interventionist policies or emphasize structural and political factors. (KC)

Effectiveness of groundwater governance structures and institutions in Tanzania

NASA Astrophysics Data System (ADS)

Gudaga, J. L.; Kabote, S. J.; Tarimo, A. K. P. R.; Mosha, D. B.; Kashaigili, J. J.

2018-05-01

This paper examines effectiveness of groundwater governance structures and institutions in Mbarali District, Mbeya Region. The paper adopts exploratory sequential research design to collect quantitative and qualitative data. A random sample of 90 groundwater users with 50% women was involved in the survey. Descriptive statistics, Kruskal-Wallis H test and Mann-Whitney U test were used to compare the differences in responses between groups, while qualitative data were subjected to content analysis. The results show that the Village Councils and Community Water Supply Organizations (COWSOs) were effective in governing groundwater. The results also show statistical significant difference on the overall extent of effectiveness of the Village Councils in governing groundwater between villages ( P = 0.0001), yet there was no significant difference ( P > 0.05) between male and female responses on the effectiveness of Village Councils, village water committees and COWSOs. The Mann-Whitney U test showed statistical significant difference between male and female responses on effectiveness of formal and informal institutions ( P = 0.0001), such that informal institutions were effective relative to formal institutions. The Kruskal-Wallis H test also showed statistical significant difference ( P ≤ 0.05) on the extent of effectiveness of formal institutions, norms and values between low, medium and high categories. The paper concludes that COWSOs were more effective in governing groundwater than other groundwater governance structures. Similarly, norms and values were more effective than formal institutions. The paper recommends sensitization and awareness creation on formal institutions so that they can influence water users' behaviour to govern groundwater.

Implementing an effective organization and governance structure for a radiology practice.

PubMed

Muroff, Lawrence R

2004-01-01

Radiology practices that are well organized and effectively governed have a competitive advantage. Decisions are made rapidly, actions are taken decisively and in accordance with established policy, and each group member has a responsibility for practice building. Such groups are perceived by their peers, hospital administration, and community business leaders to be both formidable and effective. This paper details the mechanisms that facilitate planning for and implementing an efficient practice organization and governance structure. The tasks of group leaders are defined, as are the committees necessary for appropriate action. The integral roles of a mission statement and a business plan are discussed. Practices adopting the suggested organizational structure will be best positioned to survive in both good times and bad.

Using a shared governance structure to evaluate the implementation of a new model of care: the shared experience of a performance improvement committee.

PubMed

Myers, Mary; Parchen, Debra; Geraci, Marilla; Brenholtz, Roger; Knisely-Carrigan, Denise; Hastings, Clare

2013-10-01

Sustaining change in the behaviors and habits of experienced practicing nurses can be frustrating and daunting, even when changes are based on evidence. Partnering with an active shared governance structure to communicate change and elicit feedback is an established method to foster partnership, equity, accountability, and ownership. Few recent exemplars in the literature link shared governance, change management, and evidence-based practice to transitions in care models. This article describes an innovative staff-driven approach used by nurses in a shared governance performance improvement committee to use evidence-based practice in determining the best methods to evaluate the implementation of a new model of care.

Reclaiming respectability? The class-cultural dynamics of crime, community and governance in inner-city Dublin.

PubMed

Ilan, Jonathan

2011-01-01

This paper critically examines developments in Irish urban governance through an ethnographic account of one community's historical memory and contemporary structure. During an era of rapid economic growth, the Irish state has courted previously excluded communities, offering them greater "inclusion" as "partners" in responding to urban decay and crime. The micro-governance structures this creates, however, become sites of contest between competing community factions and class-cultural imperatives. Tensions emerge between aspirational community leaders championing the aesthetics (if not the values) of "respectability" and residual residents who are presented as "rough". The paper demonstrates that nuances of class-cultural identity dictate the character of partnership governance at the community level with particular implications for local regeneration and crime control agendas.

Using a Shared Governance Structure to Evaluate the Implementation of a New Model of Care: The Shared Experience of a Performance Improvement Committee

PubMed Central

Myers, Mary; Parchen, Debra; Geraci, Marilla; Brenholtz, Roger; Knisely-Carrigan, Denise; Hastings, Clare

2013-01-01

Sustaining change in the behaviors and habits of experienced practicing nurses can be frustrating and daunting, even when changes are based on evidence. Partnering with an active shared governance structure to communicate change and elicit feedback is an established method to foster partnership, equity, accountability and ownership. Few recent exemplars in the literature link shared governance, change management and evidence-based practice to transitions in care models. This article describes an innovative staff-driven approach used by nurses in a shared governance performance improvement committee to use evidence based practice in determining the best methods to evaluate the implementation of a new model of care. PMID:24061583

Governance and community benefit: are nonprofit hospitals good candidates for Sarbanes-Oxley type reforms?

PubMed

Alexander, Jeffrey A; Young, Gary J; Weiner, Bryan J; Hearld, Larry R

2008-04-01

Recent investigations into the activities of nonprofit hospitals have pointed to weak or lax governance on the part of some of these organizations. As a result of these events, various federal and state initiatives are now either under way or under discussion to strengthen the governance of hospitals and other nonprofit corporations through mandatory board structures and practices. However, despite policy makers' growing interest in these types of governance reforms, there is in fact little empirical evidence to support their contribution to the effectiveness of hospital boards. The purpose of this article is to report the results of a study examining the relationship between the structure and practices of nonprofit hospital boards relative to the hospital's provision of community benefits. Our results point to modest relationships between these sets of variables, suggesting considerable limitations to what federal and state policy makers can accomplish through legislative initiatives to improve the governance of nonprofit hospitals.

Force and moment rotordynamic coefficients for pump-impeller shroud surfaces

NASA Technical Reports Server (NTRS)

Childs, Dara W.

1987-01-01

Governing equations of motion are derived for a bulk-flow model of the leakage path between an impeller shroud and a pump housing. The governing equations consist of a path-momentum, a circumferential - momentum, and a continuity equation. The fluid annulus between the impeller shroud and pump housing is assumed to be circumferentially symmetric when the impeller is centered; i.e., the clearance can vary along the pump axis but does not vary in the circumferential direction. A perturbation expansion of the governing equations in the eccentricity ratio yields a set of zeroth and first-order governing equations. The zeroth-order equations define the leaking rate and the circumferential and path velocity distributions and pressure distributions for a centered impeller position. The first-order equations define the perturbations in the velocity and pressure distributions due to either a radial-displacement perturbation or a tilt perturbation of the impeller. Integration of the perturbed pressure and shear-stress distribution acting on the rotor yields the reaction forces and moments acting on the impeller face.

Disaster Governance for Community Resilience in Coastal Towns: Chilean Case Studies.

PubMed

Villagra, Paula; Quintana, Carolina

2017-09-14

This study aimed to further our understanding of a characteristic of Community Resilience known as Disaster Governance. Three attributes of Disaster Governance-redundancy, diversity, and overlap-were studied in four coastal towns in southern Chile that are at risk of tsunamis. Overall, we explored how different spatial structures of human settlements influence Disaster Governance. Using the Projective Mapping Technique, the distribution of emergency institutions (N = 32) and uses given to specific sites (e.g., for refuge, sanitary purposes and medical attention) were mapped. Content and GIS analyses (Directional Distribution and Kernel Density Index) were used to explore the dispersion and concentration of institutions and uses in each town. Disaster Governance was found to be highly influenced by decisions taken during regional, urban, and emergency planning. Governance is better in towns of higher order in the communal hierarchical structure. Most of the emergency institutions were found to be located in central and urban areas, which, in turn, assures more redundancy, overlap, and diversity in governance in the event of a tsunami. Lack of flexibility of emergency plans also limits governance in rural and indigenous areas. While the spatial relationships found in this study indicate that urban sectors have better Disaster Governance than rural and indigenous sectors, the influence of resource availability after tsunamis, the role and responsibility of different levels of governments, and the politics of disaster also play an important role in Disaster Governance for determining Community Resilience. These findings shed light on emergency planning and aspects of the Disaster Management cycle.

Catalytic distillation structure

DOEpatents

Smith, Jr., Lawrence A.

1984-01-01

Catalytic distillation structure for use in reaction distillation columns, a providing reaction sites and distillation structure and consisting of a catalyst component and a resilient component intimately associated therewith. The resilient component has at least about 70 volume % open space and being present with the catalyst component in an amount such that the catalytic distillation structure consist of at least 10 volume % open space.

Health System Creation and Integration at a Health Sciences University: A Five-Year Follow-up.

PubMed

Slade, Catherine P; Azziz, Ricardo; Levin, Steven; Caughman, Gretchen B; Hefner, David S; Halbur, Kimberly V; Tingen, Martha S; James, Susan

Shifting healthcare market forces and regulation have exerted near-constant pressure on U.S. academic health centers (AHCs) attempting to successfully execute their traditional tripartite mission. A governance structure and organizational alignment that works well under one set of conditions is rarely optimal when conditions change. Thus, the degree and type of alignment of an AHC's clinical, educational, and faculty practice organizations have changed regularly within the sector, typically landing near one end or the other on a continuum from fully aligned with centralized governance to largely independent with separate governance. The authors examine the case of Georgia Regents University and Health System in this context. In step with industry trends, the institution's governance structure swung from fully aligned/centralized governance in the early 1990s to essentially separate and decentralized by 2000. In 2010, the Georgia Regents University organizations achieved rapid realignment by creating a governance structure of sufficient strength and flexibility to absorb and adjust to continuing external upheaval. The hospitals, clinics, and physician-faculty practice group were combined into one integrated health system, then aligned with the university to form the state's only public AHC under aligned, but distinct, corporate and management structures. The years since reorganization have seen significant growth in patient volumes and complexity, improved service quality, and enhanced faculty physician satisfaction, while also significantly increasing economic contributions from the health system to the academic mission. This case study offers observations and lessons learned that may be useful to other higher education institutions considering reorganization.

Molecular-Scale Study of Aspartate Adsorption on Goethite and Competition with Phosphate.

PubMed

Yang, Yanli; Wang, Shengrui; Xu, Yisheng; Zheng, Binghui; Liu, Jingyang

2016-03-15

Knowledge of the interfacial interactions between aspartate and minerals, especially its competition with phosphate, is critical to understanding the fate and transport of amino acids in the environment. Adsorption reactions play important roles in the mobility, bioavailability, and degradation of aspartate and phosphate. Attenuated total reflectance Fourier-transform infrared (ATR-FTIR) measurements and density functional theory (DFT) calculations were used to investigate the interfacial structures and their relative contributions in single-adsorbate and competition systems. Our results suggest three dominant mechanisms for aspartate: bidentate inner-sphere coordination involving both α- and γ-COO(-), outer-sphere complexation via electrostatic attraction and H-bonding between aspartate NH2 and goethite surface hydroxyls. The interfacial aspartate is mainly governed by pH and is less sensitive to changes of ionic strength and aspartate concentration. The phosphate competition significantly reduces the adsorption capacity of aspartate on goethite. Whereas phosphate adsorption is less affected by the presence of aspartate, including the relative contributions of diprotonated monodentate, monoprotonated bidentate, and nonprotonated bidentate structures. The adsorption process facilitates the removal of bioavailable aspartate and phosphate from the soil solution as well as from the sediment pore water and the overlying water.

Method of fabricating free-form, high-aspect ratio components for high-current, high-speed microelectrics

DOEpatents

Maxwell, James L; Rose, Chris R; Black, Marcie R; Springer, Robert W

2014-03-11

Microelectronic structures and devices, and method of fabricating a three-dimensional microelectronic structure is provided, comprising passing a first precursor material for a selected three-dimensional microelectronic structure into a reaction chamber at temperatures sufficient to maintain said precursor material in a predominantly gaseous state; maintaining said reaction chamber under sufficient pressures to enhance formation of a first portion of said three-dimensional microelectronic structure; applying an electric field between an electrode and said microelectronic structure at a desired point under conditions whereat said first portion of a selected three-dimensional microelectronic structure is formed from said first precursor material; positionally adjusting either said formed three-dimensional microelectronic structure or said electrode whereby further controlled growth of said three-dimensional microelectronic structure occurs; passing a second precursor material for a selected three-dimensional microelectronic structure into a reaction chamber at temperatures sufficient to maintain said precursor material in a predominantly gaseous state; maintaining said reaction chamber under sufficient pressures whereby a second portion of said three-dimensional microelectronic structure formation is enhanced; applying an electric field between an electrode and said microelectronic structure at a desired point under conditions whereat said second portion of a selected three-dimensional microelectronic structure is formed from said second precursor material; and, positionally adjusting either said formed three-dimensional microelectronic structure or said electrode whereby further controlled growth of said three-dimensional microelectronic structure occurs.

14 CFR 25.519 - Jacking and tie-down provisions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... structure must be designed for a vertical load of 1.33 times the vertical static reaction at each jacking point acting singly and in combination with a horizontal load of 0.33 times the vertical static reaction...: (i) The airplane structure must be designed for a vertical load of 1.33 times the vertical reaction...

14 CFR 25.519 - Jacking and tie-down provisions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... structure must be designed for a vertical load of 1.33 times the vertical static reaction at each jacking point acting singly and in combination with a horizontal load of 0.33 times the vertical static reaction...: (i) The airplane structure must be designed for a vertical load of 1.33 times the vertical reaction...

14 CFR 25.519 - Jacking and tie-down provisions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... structure must be designed for a vertical load of 1.33 times the vertical static reaction at each jacking point acting singly and in combination with a horizontal load of 0.33 times the vertical static reaction...: (i) The airplane structure must be designed for a vertical load of 1.33 times the vertical reaction...

14 CFR 25.519 - Jacking and tie-down provisions.

Code of Federal Regulations, 2010 CFR

2010-01-01

... structure must be designed for a vertical load of 1.33 times the vertical static reaction at each jacking point acting singly and in combination with a horizontal load of 0.33 times the vertical static reaction...: (i) The airplane structure must be designed for a vertical load of 1.33 times the vertical reaction...

14 CFR 25.519 - Jacking and tie-down provisions.

Code of Federal Regulations, 2011 CFR

2011-01-01

... structure must be designed for a vertical load of 1.33 times the vertical static reaction at each jacking point acting singly and in combination with a horizontal load of 0.33 times the vertical static reaction...: (i) The airplane structure must be designed for a vertical load of 1.33 times the vertical reaction...

Analysis of the effects of firing Orbiter primary reaction control system jets with an attached truss structure

NASA Technical Reports Server (NTRS)

Kaszubowski, M.; Raney, J. P.

1986-01-01

A study was conducted to determine the dynamic effects of firing the orbiter primary reaction control jets during assembly of protoflight space station structure. Maximum longeron compressive load was calculated as a function of jet pulse time length, number of jet pulses, and total torque imposed by the reaction control jets. The study shows that it is possible to fire selected jets to achieve a pitch maneuver without causing failure of the attached structure.

Views on System Governance. AASCU Studies, No. 2, 1980.

ERIC Educational Resources Information Center

Delaney, Harold; And Others

Four articles on changing governance patterns of state colleges and universities are presented. In "State Control vs. Campus Autonomy: A Struggle for Balance," Donald E. Walters discusses the distribution of power in Illinois'"system of systems" governance structure. In Illinois several multi-campus university systems coexist;…

Governance in English VET: On the Functioning of a Fractured "System"

ERIC Educational Resources Information Center

Keep, Ewart

2015-01-01

This article explores the governance structures that cover vocational education and training (VET) in England. The English VET system is highly fragmented, complex and unstable, and has tended to oscillate between centralised command and control, and attempts at marketisation. Its governance arrangements reflect this situation. The various…

A Conceptual Framework for Achieving Good Governance at Open and Distance Learning Institutions

ERIC Educational Resources Information Center

Khanna, Pankaj

2017-01-01

This paper describes a good governance architecture framework that would bring significant improvements in the overall working of open and distance learning institutions in a well-structured and systematic way. The good governance framework is articulated with seven basic principles which are performance, transparency, accountability,…

Report of the Committee on Government Organization.

ERIC Educational Resources Information Center

Jenks, R. Stephen; And Others

This report presents in detail a unicameral government structure with supporting student and faculty caucuses, recommended for the University of New Hampshire by its Committee on Government Organization to (1) provide maximum participation to all members of the university community on a fair and equitable basis, and (2) provide a more efficient…

Perspectives on Governance in Community Colleges Using Different Organizational Models.

ERIC Educational Resources Information Center

McCauley, Lisa Marie

This paper discusses three ways of structuring community college governmental bodies and describes the benefits of a combined approach to governance. To remain true to their purpose of serving the community, governing bodies for two-year colleges must consist of representatives from the surrounding community. Although community college governing…

The Applicability of Governance at King Saud University in Riyadh

ERIC Educational Resources Information Center

Kentab, Mohammad Y.

2018-01-01

The problem of the study revolves around the application of the requirements of governance at King Saud University. The study aims to identify the extent of governance requirements at King Saud University as seen by faculty members through transparency, accountability, organizational structure, laws, regulations, and justice. To achieve the…

Colleges and the Governance of Higher Education

ERIC Educational Resources Information Center

Parry, Gareth

2013-01-01

The governance of higher education in colleges and college sectors that offer other types of education and training is distinctive in four main respects. First, governance structures are frequently separate and different for higher education and for other segments of tertiary education. Second, the size and scope of the higher-level education…

The Role of Democratic Governing Bodies in South African Schools.

ERIC Educational Resources Information Center

Karlsson, Jenni

2002-01-01

School governance reform in post-apartheid South Africa aimed to democratize schooling while accommodating diverse school histories of underdevelopment or self-management. Analysis of relevant legislation shows the reform was structured to allow representative democracy and partnerships. But two recent studies suggest that governance reforms have…

Hypersensitive Reaction to Tattoos: A Growing Menace in Rural India

PubMed Central

Shashikumar, B M; Harish, M R; Shwetha, B; Kavya, M; Deepadarshan, K; Phani, H N

2017-01-01

Background: Increased enthusiasm toward newer fashion trends among rural India along with the lack of government regulation has led to increased tattoo reactions. Objective: The objective of this study is to describe various clinical manifestations of hypersensitive reactions to tattoo ink reported at a tertiary care hospital in Mandya district. Materials and Methods: An observational study was carried out over a period of 1 year from June 2014 to May 2015 at Mandya Institute of Medical Sciences, Mandya. All the patients reporting with allergic reaction due to tattooing were included in the present study after obtaining informed consent. Transient acute inflammatory reaction, infections, and skin diseases localized on tattooed area were excluded from this study. A detailed history regarding the onset, duration and color used for tattooing were collected. Cutaneous examination and biopsy was to done to know the type of reaction. Results: Fifty cutaneous allergic reactions were diagnosed among 39 patients. Mean age of subjects was 22 years and mean duration before the appearance of lesion was 7 months. Common colors associated with reactions were red (53.9%), black (33.3%), green (5.1%), and multicolor (7.7%). Itching was the predominant symptom. Skin lesions mainly consisted of lichenoid papules and plaques, eczematous lesions, and verrucous lesions. Lichenoid histopathology reaction was the most common tissue allergic reaction. Conclusion: Increasing popularity of tattooing among young people has predisposed to parallel increase in adverse reactions. Red pigment is most common cause of allergic reaction in the present study, and lichenoid reaction is the most common reaction. PMID:28584372

Multistructural microiteration technique for geometry optimization and reaction path calculation in large systems.

PubMed

Suzuki, Kimichi; Morokuma, Keiji; Maeda, Satoshi

2017-10-05

We propose a multistructural microiteration (MSM) method for geometry optimization and reaction path calculation in large systems. MSM is a simple extension of the geometrical microiteration technique. In conventional microiteration, the structure of the non-reaction-center (surrounding) part is optimized by fixing atoms in the reaction-center part before displacements of the reaction-center atoms. In this method, the surrounding part is described as the weighted sum of multiple surrounding structures that are independently optimized. Then, geometric displacements of the reaction-center atoms are performed in the mean field generated by the weighted sum of the surrounding parts. MSM was combined with the QM/MM-ONIOM method and applied to chemical reactions in aqueous solution or enzyme. In all three cases, MSM gave lower reaction energy profiles than the QM/MM-ONIOM-microiteration method over the entire reaction paths with comparable computational costs. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Cooperativity governs the size and structure of biological interfaces.

PubMed

Qin, Zhao; Buehler, Markus J

2012-11-15

Interfaces, defined as the surface of interactions between two parts of a system at a discontinuity, are very widely found in nature. While it is known that the specific structure of an interface plays an important role in defining its properties, it is less clear whether or not there exist universal scaling laws that govern the structural evolution of a very broad range of natural interfaces. Here we show that cooperativity of interacting elements, leading to great strength at low material use, is a key concept that governs the structural evolution of many natural interfaces. We demonstrate this concept for the cases of β-sheet proteins in spider silk, gecko feet, legs of caterpillars, and self-assembling of penguins into huddles, which range in scales from the submolecular to the macroscopic level. A general model is proposed that explains the size and structure of biological interfaces from a fundamental point of view. Copyright © 2012 Elsevier Ltd. All rights reserved.

Progress in aminosugar derived asymmetric organocatalysis.

PubMed

Agarwal, Jyoti

2016-11-22

In the last decade aminosugars, especially d-glucoamine based organocatalysts, have been applied to catalyze various asymmetric reactions such as aldol reactions, Michael addition, Strecker reactions, Biginelli reactions, epoxidation, fluorination, and imine reduction, and for the synthesis of various biologically important molecules such as 3-alkylnitro-2-hydroxynaphthoquinones, trans-dihydrobenzofurans etc. Immense growth has been also observed in the structural modification of aminosugar based organocatalysts to obtain the best results from them. This review sheds light on such organocatalytic transformations reported in last the decade including the effect of the structural modification of sugar amines on their catalytic efficiency and the stereoselectivity of the reaction.

OAS :: Our Structure

Science.gov Websites

General Assembly Governance H Human Development Human Rights I Indigenous Peoples Integral Development Scholarships School of Governance Science and Technology Social Development Summits of the Americas Sustainable

Gas-Phase Reactions of Dimethyl Disulfide with Aliphatic Carbanions - A Mass Spectrometry and Computational Study

NASA Astrophysics Data System (ADS)

Franczuk, Barbara; Danikiewicz, Witold

2018-03-01

Ion-molecule reactions of Me2S2 with a wide range of aliphatic carbanions differing by structure and proton affinity values have been studied in the gas phase using mass spectrometry techniques and DFT calculations. The analysis of the spectra shows a variety of product ions formed via different reaction mechanisms, depending on the structure and proton affinity of the carbanion. Product ions of thiophilic reaction ( m/z 47), SN2 ( m/z 79), and E2 elimination - addition sequence of reactions ( m/z 93) can be observed. Primary products of thiophilic reaction can undergo subsequent SN2 and proton transfer reactions. Gibbs free energy profiles calculated for experimentally observed reactions using PBE0/6-311+G(2d,p) method show good agreement with experimental results. [Figure not available: see fulltext.

Reproductive technology: in Britain, the debate after the Warnock Report.

PubMed

Gillon, Raanan

1987-06-01

Gillon contributes an article on Great Britain to the Hastings Center Report series on reproductive technologies outside the United States. In 1984 the Warnock Committee's report represented the first attempt by a national government to formulate a policy on reproductive issues such as artificial insemination, in vitro fertilization, surrogate mothers, and research on human embryos. Reaction to the Warnock report has focused on its recommendations to ban commercial surrogacy and to allow experimentation on embryos up to 14 days after fertilization. Legislation on surrogacy was passed in 1985, while bills banning embryo research failed in 1986. A 1986 government consultation paper called for discussion of other aspects of the Warnock report, including its recommendation that a statutory licensing authority to regulate reproductive technologies be established. Gillon predicts that no new legislation will be enacted under the present government.

Measurement of the reaction 2H(e,e') at 180 degrees close to the deuteron breakup threshold.

PubMed

Ryezayeva, N; Arenhövel, H; Burda, O; Byelikov, A; Chernykh, M; Enders, J; Griesshammer, H W; Kalmykov, Y; von Neumann-Cosel, P; Ozel, B; Poltoratska, I; Pysmenetska, I; Rangacharyulu, C; Rathi, S; Richter, A; Schrieder, G; Shevchenko, A; Yevetska, O

2008-05-02

Inclusive inelastic electron scattering off the deuteron under 180 degrees has been studied at the S-DALINAC close to the breakup threshold at momentum transfers q=0.27 fm;{-1} and 0.74 fm;{-1} with good energy resolution sufficient to map in detail the spin flip M1 response, which governs the starting reaction pn-->dgamma of big-bang nucleosynthesis over most of the relevant temperature region. Results from potential model calculations and (for q=0.27 fm;{-1}) from pionless nuclear effective field theory are in excellent agreement with the data.

Double slip effects of Magnetohydrodynamic (MHD) boundary layer flow over an exponentially stretching sheet with radiation, heat source and chemical reaction

NASA Astrophysics Data System (ADS)

Shaharuz Zaman, Azmanira; Aziz, Ahmad Sukri Abd; Ali, Zaileha Md

2017-09-01

The double slips effect on the magnetohydrodynamic boundary layer flow over an exponentially stretching sheet with suction/blowing, radiation, chemical reaction and heat source is presented in this analysis. By using the similarity transformation, the governing partial differential equations of momentum, energy and concentration are transformed into the non-linear ordinary equations. These equations are solved using Runge-Kutta-Fehlberg method with shooting technique in MAPLE software environment. The effects of the various parameter on the velocity, temperature and concentration profiles are graphically presented and discussed.

Numerical analysis of MHD Carreau fluid flow over a stretching cylinder with homogenous-heterogeneous reactions

NASA Astrophysics Data System (ADS)

Khan, Imad; Ullah, Shafquat; Malik, M. Y.; Hussain, Arif

2018-06-01

The current analysis concentrates on the numerical solution of MHD Carreau fluid flow over a stretching cylinder under the influences of homogeneous-heterogeneous reactions. Modelled non-linear partial differential equations are converted into ordinary differential equations by using suitable transformations. The resulting system of equations is solved with the aid of shooting algorithm supported by fifth order Runge-Kutta integration scheme. The impact of non-dimensional governing parameters on the velocity, temperature, skin friction coefficient and local Nusselt number are comprehensively delineated with the help of graphs and tables.

A systematic policy approach to changing the food system and physical activity environments to prevent obesity.

PubMed

Sacks, Gary; Swinburn, Boyd A; Lawrence, Mark A

2008-06-05

As obesity prevention becomes an increasing health priority in many countries, including Australia and New Zealand, the challenge that governments are now facing is how to adopt a systematic policy approach to increase healthy eating and regular physical activity. This article sets out a structure for systematically identifying areas for obesity prevention policy action across the food system and full range of physical activity environments. Areas amenable to policy intervention can be systematically identified by considering policy opportunities for each level of governance (local, state, national, international and organisational) in each sector of the food system (primary production, food processing, distribution, marketing, retail, catering and food service) and each sector that influences physical activity environments (infrastructure and planning, education, employment, transport, sport and recreation). Analysis grids are used to illustrate, in a structured fashion, the broad array of areas amenable to legal and regulatory intervention across all levels of governance and all relevant sectors. In the Australian context, potential regulatory policy intervention areas are widespread throughout the food system, e.g., land-use zoning (primary production within local government), food safety (food processing within state government), food labelling (retail within national government). Policy areas for influencing physical activity are predominantly local and state government responsibilities including, for example, walking and cycling environments (infrastructure and planning sector) and physical activity education in schools (education sector). The analysis structure presented in this article provides a tool to systematically identify policy gaps, barriers and opportunities for obesity prevention, as part of the process of developing and implementing a comprehensive obesity prevention strategy. It also serves to highlight the need for a coordinated approach to policy development and implementation across all levels of government in order to ensure complementary policy action.

Kinetics and mechanism of hydroxyapatite crystal dissolution in weak acid buffers using the rotating disk method.

PubMed

Wu, M S; Higuchi, W I; Fox, J L; Friedman, M

1976-01-01

The model given in this report and the rotating disk method provide a useful combination in the study of dental enamel and hydroxyapatite dissolution kinetics. The present approach is a significant improvement over earlier studies, and both the ionic activity product that governs the dissolution reaction and the apparent surface dissolution reaction rate constant may be simultaneously obtained. Thus, these investigations have established the baseline for the dissolution rate studies under sink conditions. Concurrent studies, under conditions where the acidic buffer mediums are partially saturated with respect to hydroxyapatite have shown another dissolution site for hydroxyapatite that operates at a higher ionic activity product but has a much smaller apparent surface reaction rate constant. This has raised the question of whether the presence of this second site may interfere with the proper theoretical analysis of the experimental results obtained under sink conditions. A preliminary analysis of the two-site model has shown that the dissolution kinetics of hydroxyapatite under sink conditions is almost completely governed by the sink condition site (KHAP = 10(-124.5), k' = 174) established in this report. The difference between the predicted dissolution rate for the one-site model and the two-site model are generally of the order of 4 to 5% where the experiments are conducted under sink conditions and over the range of variables covered in the present study.

Catalytic distillation structure

DOEpatents

Smith, L.A. Jr.

1984-04-17

Catalytic distillation structure is described for use in reaction distillation columns, and provides reaction sites and distillation structure consisting of a catalyst component and a resilient component intimately associated therewith. The resilient component has at least about 70 volume % open space and is present with the catalyst component in an amount such that the catalytic distillation structure consists of at least 10 volume % open space. 10 figs.

Lagrangian descriptors of driven chemical reaction manifolds.

PubMed

Craven, Galen T; Junginger, Andrej; Hernandez, Rigoberto

2017-08-01

The persistence of a transition state structure in systems driven by time-dependent environments allows the application of modern reaction rate theories to solution-phase and nonequilibrium chemical reactions. However, identifying this structure is problematic in driven systems and has been limited by theories built on series expansion about a saddle point. Recently, it has been shown that to obtain formally exact rates for reactions in thermal environments, a transition state trajectory must be constructed. Here, using optimized Lagrangian descriptors [G. T. Craven and R. Hernandez, Phys. Rev. Lett. 115, 148301 (2015)PRLTAO0031-900710.1103/PhysRevLett.115.148301], we obtain this so-called distinguished trajectory and the associated moving reaction manifolds on model energy surfaces subject to various driving and dissipative conditions. In particular, we demonstrate that this is exact for harmonic barriers in one dimension and this verification gives impetus to the application of Lagrangian descriptor-based methods in diverse classes of chemical reactions. The development of these objects is paramount in the theory of reaction dynamics as the transition state structure and its underlying network of manifolds directly dictate reactivity and selectivity.

The home hemodialysis hub: physical infrastructure and integrated governance structure.

PubMed

Marshall, Mark R; Young, Bessie A; Fox, Sally J; Cleland, Calli J; Walker, Robert J; Masakane, Ikuto; Herold, Aaron M

2015-04-01

An effective home hemodialysis program critically depends on adequate hub facilities and support functions and on transparent and accountable organizational processes. The likelihood of optimal service delivery and patient care will be enhanced by fit-for-purpose facilities and implementation of a well-considered governance structure. In this article, we describe the required accommodation and infrastructure for a home hemodialysis program and a generic organizational structure that will support both patient-facing clinical activities and business processes. © 2015 International Society for Hemodialysis.

8 CFR 499.1 - Prescribed forms.

Code of Federal Regulations, 2011 CFR

2011-01-01

... shown or a subsequent edition date. Form No. Edition date Title and description M-288 12-30-87 United States History 1600-1987, Level II. M-289 12-31-87 United States History 1600-1987, Level I. M-290 01-01-90 U.S. Government Structure, Level II. M-291 12-31-87 U.S. Government Structure, Level I. M-302 03...

8 CFR 499.1 - Prescribed forms.

Code of Federal Regulations, 2010 CFR

2010-01-01

... shown or a subsequent edition date. Form No. Edition date Title and description M-288 12-30-87 United States History 1600-1987, Level II. M-289 12-31-87 United States History 1600-1987, Level I. M-290 01-01-90 U.S. Government Structure, Level II. M-291 12-31-87 U.S. Government Structure, Level I. M-302 03...

Governance and Management Structures for Community Partnerships: Experiences from the Robert Wood Johnson Foundation's Community Partnerships for Older Adults Program

ERIC Educational Resources Information Center

Bolda, Elise J.; Saucier, Paul; Maddux, George L.; Wetle, Terrie; Lowe, Jane Isaacs

2006-01-01

Purpose: This article describes early efforts of four community partnerships in Boston, El Paso, Houston, and Milwaukee to address governance and management structures in ways that promote the sustainability of innovative community-based long-term care system improvements. The four communities are grantees of the Community Partnerships for Older…

Linkages among Education, Health, and Social Services Systems in States That Are Creating New Governance Structures.

ERIC Educational Resources Information Center

Mutchler, Sue E.; Pollard, Joyce S.

As they work to develop integrated, community-driven service systems that meet the constellation of needs of children and families, several states are beginning to develop new governance structures at the local level. This paper describes the ways in which states are creating or supporting linkages among education, health, and human services. A…

77 FR 5284 - Self-Regulatory Organizations; The Options Clearing Corporation; Notice of Filing of Proposed...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-02-02

... governance structure of OCC by (i) increasing the number of public directors on the Board from one to three... any comments it received on the proposed rule change. The text of these statements may be examined at... change is to modify the corporate governance structure of OCC by (i) increasing the number of public...

Information Technology Governance, Funding and Structure: A Case Analysis of a Public University in Malaysia

ERIC Educational Resources Information Center

Ismail, Noor Azizi

2008-01-01

Purpose: The paper's purpose is to investigate the issues of IT governance, funding and structure of a public university in Malaysia. Design/methodology/approach: The study uses a case study approach, i.e. a series of interviews with users and information services provider of campus information system. Findings: The university lacks a common…

The Emergence of Cambodian Civil Society within Global Educational Governance: A Morphogenetic Approach to Agency and Structure

ERIC Educational Resources Information Center

Edwards, D. Brent, Jr.; Brehm, William C.

2015-01-01

This paper uses Margaret Archer's morphogenetic approach to analyze the emergence of civil society within global educational governance. The purpose is to understand the intersection of historical structures with global actors and spaces that have accompanied the globalization of education. Based on findings from a study on the impact in Cambodia…

Lessons from industry: one school's transformation toward "lean" curricular governance.

PubMed

Stratton, Terry D; Rudy, David W; Sauer, Marlene J; Perman, Jay A; Jennings, C Darrell

2007-04-01

As medical education grapples with organizational calls for centralized curricular oversight, programs may be compelled to respond by establishing highly vertical, stacked governance structures. Although these models offer discrete advantages over the horizontal, compartmentalized structures they are designed to replace, they pose new challenges to ensuring curricular quality and the educational innovations that drive the curricula. The authors describe a hybrid quality-assurance (QA) governance structure introduced in 2003 at the University of Kentucky College of Medicine (UKCOM) that ensures centralized curricular oversight of the educational product while allowing individualized creative control over the educational process. Based on a Lean production model, this approach draws on industry experiences that strategically separate institutional accountability (management) for a quality curriculum from the decision-making processes required to ensure it (production). In so doing, the authors acknowledge general similarities and key differences between overseeing the manufacture of a complex product versus the education of a physician-emphasizing the structured, sequential, and measurable nature of each process. Further, the authors briefly trace the emergence of quality approaches in manufacturing and discuss the philosophical changes that accompany transition to an institutional governance system that relies on vigorous, robust performance measures to offer continuous feedback on curricular quality.

pH-Controlled Oxidation of an Aromatic Ketone: Structural Elucidation of the Products of Two Green Chemical Reactions

ERIC Educational Resources Information Center

Ballard, C. Eric

2010-01-01

A laboratory experiment emphasizing the structural elucidation of organic compounds has been developed as a discovery exercise. The "unknown" compounds are the products of the pH-controlled oxidation of 4'-methoxyacetophenone with bleach. The chemoselectivity of this reaction is highly dependent on the pH of the reaction media: under basic…

Atmospheric reaction of Cl + methacrolein: a theoretical study on the mechanism, and pressure- and temperature-dependent rate constants.

PubMed

Sun, Cuihong; Xu, Baoen; Zhang, Shaowen

2014-05-22

Methacrolein is a major degradation product of isoprene, the reaction of methacrolein with Cl atoms may play some roles in the degradation of isoprene where these species are relatively abundant. However, the energetics and kinetics of this reaction, which govern the reaction branching, are still not well understood so far. In the present study, two-dimensional potential energy surfaces were constructed to analyze the minimum energy path of the barrierless addition process between Cl and the C═C double bond of methacrolein, which reveals that the terminal addition intermediate is directly formed from the addition reaction. The terminal addition intermediate can further yield different products among which the reaction paths abstracting the aldehyde hydrogen atom and the methyl hydrogen atom are dominant reaction exits. The minimum reaction path for the direct aldehydic hydrogen atom abstraction is also obtained. The reaction kinetics was calculated by the variational transition state theory in conjunction with the master equation method. From the theoretical model we predicted that the overall rate constant of the Cl + methacrolein reaction at 297 K and atmospheric pressure is koverall = 2.3× 10(-10) cm(3) molecule(-1) s(-1), and the branching ratio of the aldehydic hydrogen abstraction is about 12%. The reaction is pressure dependent at P < 10 Torr with the high pressure limit at about 100 Torr. The calculated results could well account for the experimental observations.

Nanotechnology and the need for risk governance

NASA Astrophysics Data System (ADS)

Renn, O.; Roco, M. C.

2006-04-01

After identifying the main characteristics and prospects of nanotechnology as an emerging technology, the paper presents the general risks associated with nanotechnology applications and the deficits of the risk governance process today, concluding with recommendations to governments, industry, international organizations and other stakeholders. The International Risk Governance Council (IRGC) has identified a governance gap between the requirements pertaining to the nano- rather than the micro-/macro- technologies. The novel attributes of nanotechnology demand different routes for risk-benefit assessment and risk management, and at present, nanotechnology innovation proceeds ahead of the policy and regulatory environment. In the shorter term, the governance gap is significant for those passive nanostructures that are currently in production and have high exposure rates; and is especially significant for the several `active' nanoscale structures and nanosystems that we can expect to be on the market in the near future. Active nanoscale structures and nanosystems have the potential to affect not only human health and the environment but also aspects of social lifestyle, human identity and cultural values. The main recommendations of the report deal with selected higher risk nanotechnology applications, short- and long-term issues, and global models for nanotechnology governance.

The Key Role of Experiential Uncertainty when Dealing with Risks: Its Relationships with Demand for Regulation and Institutional Trust.

PubMed

Poortvliet, P Marijn; Lokhorst, Anne Marike

2016-08-01

The results of a survey and an experiment show that experiential uncertainty-people's experience of uncertainty in risk contexts-plays a moderating role in individuals' risk-related demand for government regulation and trust in risk-managing government institutions. First, descriptions of risks were presented to respondents in a survey (N = 1,017) and their reactions to questions about experiential uncertainty, risk perception, and demand for government regulation were measured, as well as levels of risk-specific knowledge. When experiential uncertainty was high, risk perceptions had a positive relationship with demand for government regulation of risk; no such relationship showed under low experiential uncertainty. Conversely, when people experience little experiential uncertainty, having more knowledge about the risk topic involved was associated with a weaker demand for government regulation of risk. For people experiencing uncertainty, this relationship between knowledge and demand for regulation did not emerge. Second, in an experiment (N = 120), experiential uncertainty and openness in risk communication were manipulated to investigate effects on trust. In the uncertainty condition, the results showed that open versus nonopen government communication about Q-fever-a zoonosis-led to higher levels of trust in the government agency, but not in in the control condition. Altogether, this research suggests that only when people experience relatively little uncertainty about the risk, knowledge provision may preclude them from demanding government action. Also, only when persons experience uncertainty are stronger risk perceptions associated with a demand for government regulation, and they are affected by openness of risk communication in forming institutional trust. © 2016 Society for Risk Analysis.

Concept of a self-associated multimer structure of coal

DOE Office of Scientific and Technical Information (OSTI.GOV)

Gagarin, S.G.; Krichko, A.A.

1984-01-01

The paper examines the role of donor-acceptor reaction in the binding of the individual components forming the structure of the organic coal mass, and analyses the manifestations of this reaction during liquefaction. The authors put forward the concept of self-associated polymers in the coal structure, in accordance with which the organic coal mass has spatial and energetic distribution of the donor and acceptor sectors of structure. It is the specific reaction between these which produces the necessary stability to the polymer system under normal conditions. The authors propose a mechanism for the action of solvents and various additives in themore » liquefaction of coal.« less

The effect of illumination on the formation of metal halide perovskite films

NASA Astrophysics Data System (ADS)

Ummadisingu, Amita; Steier, Ludmilla; Seo, Ji-Youn; Matsui, Taisuke; Abate, Antonio; Tress, Wolfgang; Grätzel, Michael

2017-04-01

Optimizing the morphology of metal halide perovskite films is an important way to improve the performance of solar cells when these materials are used as light harvesters, because film homogeneity is correlated with photovoltaic performance. Many device architectures and processing techniques have been explored with the aim of achieving high-performance devices, including single-step deposition, sequential deposition and anti-solvent methods. Earlier studies have looked at the influence of reaction conditions on film quality, such as the concentration of the reactants and the reaction temperature. However, the precise mechanism of the reaction and the main factors that govern it are poorly understood. The consequent lack of control is the main reason for the large variability observed in perovskite morphology and the related solar-cell performance. Here we show that light has a strong influence on the rate of perovskite formation and on film morphology in both of the main deposition methods currently used: sequential deposition and the anti-solvent method. We study the reaction of a metal halide (lead iodide) with an organic compound (methylammonium iodide) using confocal laser scanning fluorescence microscopy and scanning electron microscopy. The lead iodide crystallizes before the intercalation of methylammonium iodide commences, producing the methylammonium lead iodide perovskite. We find that the formation of perovskite via such a sequential deposition is much accelerated by light. The influence of light on morphology is reflected in a doubling of solar-cell efficiency. Conversely, using the anti-solvent method to form methyl ammonium lead iodide perovskite in a single step from the same starting materials, we find that the best photovoltaic performance is obtained when films are produced in the dark. The discovery of light-activated crystallization not only identifies a previously unknown source of variability in opto-electronic properties, but also opens up new ways of tuning morphology and structuring perovskites for various applications.

Nano-structured manganese oxide as a cathodic catalyst for enhanced oxygen reduction in a microbial fuel cell fed with a synthetic wastewater.

PubMed

Liu, Xian-Wei; Sun, Xue-Fei; Huang, Yu-Xi; Sheng, Guo-Ping; Zhou, Kang; Zeng, Raymond J; Dong, Fang; Wang, Shu-Guang; Xu, An-Wu; Tong, Zhong-Hua; Yu, Han-Qing

2010-10-01

Microbial fuel cells (MFCs) provide new opportunities for the simultaneous wastewater treatment and electricity generation. Enhanced oxygen reduction capacity of cost-effective metal-based catalysts in an air cathode is essential for the scale-up and commercialization of MFCs in the field of wastewater treatment. We demonstrated that a nano-structured MnO(x) material, prepared by an electrochemically deposition method, could be an effective catalyst for oxygen reduction in an MFC to generate electricity with the maximum power density of 772.8 mW/m(3) and remove organics when the MFC was fed with an acetate-laden synthetic wastewater. The nano-structured MnO(x) with the controllable size and morphology could be readily obtained with the electrochemical deposition method. Both morphology and manganese oxidation state of the nano-scale catalyst were largely dependent on the electrochemical preparation process, and they governed its catalytic activity and the cathodic oxygen reduction performance of the MFC accordingly. Furthermore, cyclic voltammetry (CV) performed on each nano-structured material suggests that the MnO(x) nanorods had an electrochemical activity towards oxygen reduction reaction via a four-electron pathway in a neutral pH solution. This work provides useful information on the facile preparation of cost-effective cathodic catalysts in a controllable way for the single-chamber air-cathode MFC for wastewater treatment. Copyright © 2010 Elsevier Ltd. All rights reserved.

Considering Governance for Patient Access to E-Medical Records.

PubMed

Day, Karen; Wells, Susan

2015-01-01

People having access to their medical records could have a transformative improvement effect on healthcare delivery and use. Our research aimed to explore the concerns and attitudes of giving people electronic access to their medical records through patient portals. We conducted 28 semi-structured interviews with 30 people, asking questions about portal design, organisational implications and governance. We report the findings of the governance considerations raised during the interviews. These revealed that (1) there is uncertainty about the possible design and extent of giving people access to their medical records to view/use, (2) existing policies about patient authentication, proxy, and privacy require modification, and (3) existing governance structures and functions require further examination and adjustment. Future research should include more input from patients and health informaticians.

Higher Education in Texas: Student Aid and Governance. Working Paper.

ERIC Educational Resources Information Center

Tolo, Kenneth W.

Current issues facing higher education in Texas are examined with an emphasis on student financial aid programs and governance. The formal organizational structure and the responsibilities of the major governmental units are described, and the role played by state government in higher education through its tuition policies and its student aid…

Governing Urban School Districts: Efforts in Los Angeles to Effect Change

ERIC Educational Resources Information Center

Augustine, Catherine H.; Epstein, Diana; Vuollo, Mirka

2006-01-01

Many urban school district students are dropping out and few of the remaining ones reach state or district achievement goals. These problems make governing urban schools both difficult and important. In 2005-06, the governance structure of the Los Angeles Unified School District (LAUSD) was examined, debated, criticized, and praised by several…

Balancing stability and flexibility in adaptive governance: an analysis of tools available in U.S. environmental law

EPA Science Inventory

Adaptive governance must work “on the ground,” that is, it must operate through structures and procedures that the people it governs perceive to be legitimate and fair, as well as incorporating processes and substantive goals that are effective in allowing social-ecological syste...

3 CFR 13547 - Executive Order 13547 of July 19, 2010. Stewardship of the Ocean, Our Coasts, and the Great Lakes

Code of Federal Regulations, 2011 CFR

2011-01-01

... Great Lakes provide jobs, food, energy resources, ecological services, recreation, and tourism... Government, as well as participation of State, tribal, and local authorities, regional governance structures..., and assistance as the Council, through the Co-Chairs, may request. Sec. 7. Governance Coordinating...

Public Higher Education Governing Boards: The Role of Social Networks

ERIC Educational Resources Information Center

Miller, Emily R.

2011-01-01

A defining feature of American higher education is the provision for authority over the institution by an external governing board consisting of lay members of the public (Thelin, 2004). Studies of higher education governing boards typically focus on structure and performance (Kezar & Eckel, 2004; Kezar, 2006; McGuinness, 2003; Minor, 2006;…

(De)Constructing Power in Higher Education Governance Structures: An Analysis of Representation and Roles in Governing Bodies

ERIC Educational Resources Information Center

Bótas, Paulo Charles Pimentel; Huisman, Jeroen

2012-01-01

This article explores how power relations are constructed in the governance of higher education institutions. It examines and deconstructs, from a Foucauldian perspective, power relations and mechanisms in the relationship between the state and higher education institutions, and between academic and management staff. This research article…

Values of Free Government: Our Bicentennial Legacy.

ERIC Educational Resources Information Center

Patrick, John J.

1987-01-01

States that the Founders' legacy is our well-modeled government which is limited by law to protect the life, liberty, and property of individuals. Reviews some of the Founding Fathers' thoughts regarding the proper role and structure of our government. Advocates improved citizenship education and introduces the theme articles in this issue. (JDH)

The Conditioning Role of State Higher Education Governance Structures

ERIC Educational Resources Information Center

Tandberg, David A.

2013-01-01

This article reports on a study that examined whether the presence of a consolidated governing board for higher education conditions the impact various political factors have on state support for higher education. The existence of a consolidated governing board is shown to significantly alter the politics of the state higher education…

10 CFR 781.52 - Exclusive and partially exclusive licenses.

Code of Federal Regulations, 2010 CFR

2010-01-01

... subsidiaries and to affiliates within the corporate structure of which the licensee is a part, if any. However... on competition in the U.S.; (3) Projected market size; (4) The benefit to the U.S. Government, U.S... United States (including any Government agency), the States, and domestic municipal governments, unless...

Iran: U.S. Concerns and Policy Responses

DTIC Science & Technology

2014-03-05

and governments assert that the nuclear deal could give Iran additional political and economic resources to support pro-Iranian movements and regimes...such as the embattled government of Bashar Al Assad of Syria. Israeli Prime Minister Benjamin Netanyahu has openly opposed the JPA as failing to...67 Figures Figure 1. Structure of the Iranian Government

Iran: U.S. Concerns and Policy Responses

DTIC Science & Technology

2013-11-04

government of Israel expresses skepticism of Rouhani’s intentions and continues to assert that it might take unilateral military action against Iran’s...domestic reform movement as cowed by regime suppression and inactive. In September 2013, his government released nearly 80 political prisoners. For...71 Figures Figure 1. Structure of the Iranian Government

The Learning Age: Experts Give Their Views on the Government's Green Paper.

ERIC Educational Resources Information Center

Adults Learning (England), 1998

1998-01-01

Includes reactions to "The Learning Age" from the following: A.G. Watts, Richard Taylor, Richard Ely, Carole Stott, Donald Rae, John Lawton, Philippa Langton, Mary Lord, and Sarah Perman. Emphasizes the need for practitioner input from their varied experiences and for knowledge of client groups into the continuing development of the…

Omnishambles: Reactions to the Second Year of Coalition Education Policies

ERIC Educational Resources Information Center

Richards, Colin

2012-01-01

The UK's Coalition Government completed its second year in office in May 2012. Many of its policies and pronouncements have been divisive and are contributing to the dismantling of the state education system as we have known it. Here, reflecting George Orwell's observation that "Every joke against the established order is a tiny…

Gubernatorial Reactions to No Child Left Behind: Politics, Pressure, and Education Reform

ERIC Educational Resources Information Center

Fusarelli, Lance D.

2005-01-01

This article explores how federal authority exemplified in the No Child Left Behind Act (NCLB) impacts another significant trend in educational governance and control--the significant growth and expansion of gubernatorial control over education reform. After briefly outlining the history of gubernatorial activism in education reform, the reaction…

Operability and Efficiency Performance of Ultra-Compact, High Gravity (g) Combustor Concepts (Postprint)

DTIC Science & Technology

2007-07-01

the U.S. Government and is not subject to copyright protection in the United States. PAO Case Number: AFRL/WS 05-1781, 23 Aug 2005. 14. ABSTRACT...significantly. Recent modeling by Katta10 where the Lewis9 experiment was modeled using UNICORN (Unsteady Ignition and Combustion using ReactioNs), a

Promoting Scientific Faculties: Does It Work? Evidence from Italy

ERIC Educational Resources Information Center

Maestri, Virginia

2013-01-01

In reaction to the OECD-wide declining trend in scientific enrollments, the Italian government launched a policy in 2005 to promote the study of science at the university. The policy promoted extra-curricular activities for secondary school students in Chemistry, Physics, Math and Materials Science. This article evaluates the policy impact on…

Learning from Experience: A Guide to Social Impact Bond Investing

ERIC Educational Resources Information Center

Berlin, Gordon L.

2016-01-01

The social sector's hottest "impact investing" product--the social impact bond (SIB)--has generated a range of reactions, from excitement to angst. An SIB uses private funds to pay for a social, educational, or health program, and the government repays investors (plus a return) only if the program achieves prespecified results. The…

Public reaction to invasive plant species in a disturbed Colorado landscape

Treesearch

Michael T. Daab; Courtney G. Flint

2010-01-01

Invasive plant species degrade ecosystems in many ways. Controlling invasive plants is costly for government agencies, businesses, and individuals. North central Colorado is currently experiencing large-scale disturbance, and millions of acres are vulnerable to invasion because of natural and socioeconomic processes. Mountain pine beetles typically endemic to this...

Experimental and theoretical study of the influence of water on hydrolyzed product formation during the feruloylation of vegetable oil.

PubMed

Compton, David L; Evans, Kervin O; Appell, Michael

2017-07-01

Feruloylated vegetable oil is a valuable green bioproduct that has several cosmeceutical applications associated with its inherent anti-oxidant and ultraviolet-absorption properties. Hydrolyzed vegetable oil by-products can influence product quality and consistency. The formation of by-products by residual water in the enzymatic synthesis of feruloylated vegetable oil was investigated using chemical theory and experimental studies by monitoring the reaction over a 22-day period. The hydrolysis of vegetable oil is thermodynamically favored over the hydrolysis of the ethyl ferulate starting material. These results suggest that hydrolyzed vegetable oil products will be experimentally observed in greater concentrations compared to hydrolyzed ethyl ferulate products. Quantum chemical studies identified several reaction mechanisms that explain the formation of side products by water, suggesting that residual water influences product quality. Efforts to reduce residual water can improve product consistency and reduce purification costs. Published 2016. This article is a U.S. Government work and is in the public domain in the USA. Published 2016. This article is a U.S. Government work and is in the public domain in the USA.