WorldWideScience

Sample records for stage reaction step

  1. Multi-step direct reactions

    International Nuclear Information System (INIS)

    Koning, A.J.

    1992-07-01

    In recent years a variety of statistical theories has been developed concerning multistep direct (MSD) nuclear reactions. In addition, dominant in applications is a whole class of semiclassical models that may be subsumed under the heading of 'generalized exciton models'; these are basically MSD-type extensions on top of compound-like concepts. In this report the relation between their underlying statistical MSD-postulates are highlighted. A command framework is sketched that enables to generate the various MSD theories through assigning statistical properties to different parts of the nuclear Hamiltonian. Then it is shown that distinct forms of nuclear randomness are embodied in the mentioned theories. All these theories appear to be very similar at a qualitative level. In order to explain the high energy-tails and forward-peaked angular distribution typical for particles emitted in MSD reactions, it is imagined that the incident continuum particle stepwise looses its energy and direction in a sequence of collisions, thereby creating new particle-hole pairs in the target system. At each step emission may take place. The statistical aspect comes in because many continuum states are involved in the process. These are supposed to display chaotic behavior, the associated randomness assumption giving rise to important simplifications in the expression for MSD emission cross sections. This picture suggests that mentioned MSD models can be interpreted as a variant of essentially one and the same theory. 113 refs.; 25 figs.; 9 tabs

  2. Analysis of reaction schemes using maximum rates of constituent steps

    Science.gov (United States)

    Motagamwala, Ali Hussain; Dumesic, James A.

    2016-01-01

    We show that the steady-state kinetics of a chemical reaction can be analyzed analytically in terms of proposed reaction schemes composed of series of steps with stoichiometric numbers equal to unity by calculating the maximum rates of the constituent steps, rmax,i, assuming that all of the remaining steps are quasi-equilibrated. Analytical expressions can be derived in terms of rmax,i to calculate degrees of rate control for each step to determine the extent to which each step controls the rate of the overall stoichiometric reaction. The values of rmax,i can be used to predict the rate of the overall stoichiometric reaction, making it possible to estimate the observed reaction kinetics. This approach can be used for catalytic reactions to identify transition states and adsorbed species that are important in controlling catalyst performance, such that detailed calculations using electronic structure calculations (e.g., density functional theory) can be carried out for these species, whereas more approximate methods (e.g., scaling relations) are used for the remaining species. This approach to assess the feasibility of proposed reaction schemes is exact for reaction schemes where the stoichiometric coefficients of the constituent steps are equal to unity and the most abundant adsorbed species are in quasi-equilibrium with the gas phase and can be used in an approximate manner to probe the performance of more general reaction schemes, followed by more detailed analyses using full microkinetic models to determine the surface coverages by adsorbed species and the degrees of rate control of the elementary steps. PMID:27162366

  3. Analysis of reaction schemes using maximum rates of constituent steps.

    Science.gov (United States)

    Motagamwala, Ali Hussain; Dumesic, James A

    2016-05-24

    We show that the steady-state kinetics of a chemical reaction can be analyzed analytically in terms of proposed reaction schemes composed of series of steps with stoichiometric numbers equal to unity by calculating the maximum rates of the constituent steps, rmax,i, assuming that all of the remaining steps are quasi-equilibrated. Analytical expressions can be derived in terms of rmax,i to calculate degrees of rate control for each step to determine the extent to which each step controls the rate of the overall stoichiometric reaction. The values of rmax,i can be used to predict the rate of the overall stoichiometric reaction, making it possible to estimate the observed reaction kinetics. This approach can be used for catalytic reactions to identify transition states and adsorbed species that are important in controlling catalyst performance, such that detailed calculations using electronic structure calculations (e.g., density functional theory) can be carried out for these species, whereas more approximate methods (e.g., scaling relations) are used for the remaining species. This approach to assess the feasibility of proposed reaction schemes is exact for reaction schemes where the stoichiometric coefficients of the constituent steps are equal to unity and the most abundant adsorbed species are in quasi-equilibrium with the gas phase and can be used in an approximate manner to probe the performance of more general reaction schemes, followed by more detailed analyses using full microkinetic models to determine the surface coverages by adsorbed species and the degrees of rate control of the elementary steps.

  4. (DNA) fragment using two-step polymerase chain reaction (PCR)

    African Journals Online (AJOL)

    Polymerase chain reaction (PCR), an essential tool in many fields such as molecular biology, normally comprises three steps: denaturation at a high temperature, annealing at a low temperature and elongation at a moderate temperature. Here, we report a two-step PCR method which incorporates annealing and elongation ...

  5. Two-step two-stage fission gas release model

    International Nuclear Information System (INIS)

    Kim, Yong-soo; Lee, Chan-bock

    2006-01-01

    Based on the recent theoretical model, two-step two-stage model is developed which incorporates two stage diffusion processes, grain lattice and grain boundary diffusion, coupled with the two step burn-up factor in the low and high burn-up regime. FRAPCON-3 code and its in-pile data sets have been used for the benchmarking and validation of this model. Results reveals that its prediction is in better agreement with the experimental measurements than that by any model contained in the FRAPCON-3 code such as ANS 5.4, modified ANS5.4, and Forsberg-Massih model over whole burn-up range up to 70,000 MWd/MTU. (author)

  6. Staged multidisciplinary step-up management for necrotizing pancreatitis.

    Science.gov (United States)

    da Costa, D W; Boerma, D; van Santvoort, H C; Horvath, K D; Werner, J; Carter, C R; Bollen, T L; Gooszen, H G; Besselink, M G; Bakker, O J

    2014-01-01

    Some 15 per cent of all patients with acute pancreatitis develop necrotizing pancreatitis, with potentially significant consequences for both patients and healthcare services. This review summarizes the latest insights into the surgical and medical management of necrotizing pancreatitis. General management strategies for the treatment of complications are discussed in relation to the stage of the disease. Frequent clinical evaluation of the patient's condition remains paramount in the first 24-72 h of the disease. Liberal goal-directed fluid resuscitation and early enteral nutrition should be provided. Urgent endoscopic retrograde cholangiopancreatography is indicated when cholangitis is suspected, but it is unclear whether this is appropriate in patients with predicted severe biliary pancreatitis without cholangitis. Antibiotic prophylaxis does not prevent infection of necrosis and antibiotics are not indicated as part of initial management. Bacteriologically confirmed infections should receive targeted antibiotics. With the more conservative approach to necrotizing pancreatitis currently advocated, fine-needle aspiration culture of pancreatic or extrapancreatic necrosis will less often lead to a change in management and is therefore indicated less frequently. Optimal treatment of infected necrotizing pancreatitis consists of a staged multidisciplinary 'step-up' approach. The initial step is drainage, either percutaneous or transluminal, followed by surgical or endoscopic transluminal debridement only if needed. Debridement is delayed until the acute necrotic collection has become 'walled-off'. Outcome following necrotizing pancreatitis has improved substantially in recent years as a result of a shift from early surgical debridement to a staged, minimally invasive, multidisciplinary, step-up approach. © 2013 BJS Society Ltd. Published by John Wiley & Sons Ltd.

  7. The statistics of multi-step direct reactions

    International Nuclear Information System (INIS)

    Koning, A.J.; Akkermans, J.M.

    1991-01-01

    We propose a quantum-statistical framework that provides an integrated perspective on the differences and similarities between the many current models for multi-step direct reactions in the continuum. It is argued that to obtain a statistical theory two physically different approaches are conceivable to postulate randomness, respectively called leading-particle statistics and residual-system statistics. We present a new leading-particle statistics theory for multi-step direct reactions. It is shown that the model of Feshbach et al. can be derived as a simplification of this theory and thus can be founded solely upon leading-particle statistics. The models developed by Tamura et al. and Nishioka et al. are based upon residual-system statistics and hence fall into a physically different class of multi-step direct theories, although the resulting cross-section formulae for the important first step are shown to be the same. The widely used semi-classical models such as the generalized exciton model can be interpreted as further phenomenological simplifications of the leading-particle statistics theory. A more comprehensive exposition will appear before long. (author). 32 refs, 4 figs

  8. Multi-step direct reactions at low energies

    International Nuclear Information System (INIS)

    Marcinkowski, A.; Marianski, B.

    2001-01-01

    Full text: The theory of the multistep direct (MSD) reactions of Feshbach, Kerman and Koonin has for quite some time become a subject of controversy due to the bi orthogonal distorted waves involved in the transition amplitudes describing the MSD cross sections. The bi orthogonal wave functions result in non-normal DWBA matrix elements, that can be expressed in terms of normal DWBA matrix elements multiplied by the inverse elastic scattering S-matrix. It has been argued that the enhancing inverse S-factors are washed out by averaging over energy in the continuum. As a result normal DWBA matrix elements are commonly used in practical calculations. Almost all analyses of inelastic scattering and charge-exchange reactions using the DWBA matrix elements have concluded that nucleon emission at low energies can be described as one-step reaction mainly. On the other hand, it has been shown that the limits imposed by the energy weighted sum rules (EWSR's) on transition of given angular momentum transfer lead to a significant reduction of the one step cross section that can be compensated by the enhanced MSD cross sections obtained with the use of the non-normal DWBA matrix elements. Very recently the MSD theory of FKK was modified to include collective excitations and the non-normal DWBA matrix elements and the prescription for calculations of the cross sections for the MSD reactions was given. In the present paper we present the results of the modified theory used for describing the 93 Nb (n,xn) 93 Nb reaction at incident energy of 20 MeV and the 65 Cu (p,xn) 65 Zn reaction at 27 MeV. The results show enhanced contributions from two-, three- and four step reactions. We investigate the importance of the multi-phonon, multi particle hole and the mixed particle hole-phonon excitations in neutron scattering to the continuum. We also show the importance of the different sequences of collisions of the leading continuum nucleon that contribute to the MSD (p,n) reaction. When all

  9. Step-by-Step Simulation of Radiation Chemistry Using Green Functions for Diffusion-Influenced Reactions

    Science.gov (United States)

    Plante, Ianik; Cucinotta, Francis A.

    2011-01-01

    Radiolytic species are formed approximately 1 ps after the passage of ionizing radiation through matter. After their formation, they diffuse and chemically react with other radiolytic species and neighboring biological molecules, leading to various oxidative damage. Therefore, the simulation of radiation chemistry is of considerable importance to understand how radiolytic species damage biological molecules [1]. The step-by-step simulation of chemical reactions is difficult, because the radiolytic species are distributed non-homogeneously in the medium. Consequently, computational approaches based on Green functions for diffusion-influenced reactions should be used [2]. Recently, Green functions for more complex type of reactions have been published [3-4]. We have developed exact random variate generators of these Green functions [5], which will allow us to use them in radiation chemistry codes. Moreover, simulating chemistry using the Green functions is which is computationally very demanding, because the probabilities of reactions between each pair of particles should be evaluated at each timestep [2]. This kind of problem is well adapted for General Purpose Graphic Processing Units (GPGPU), which can handle a large number of similar calculations simultaneously. These new developments will allow us to include more complex reactions in chemistry codes, and to improve the calculation time. This code should be of importance to link radiation track structure simulations and DNA damage models.

  10. Considerations for the independent reaction times and step-by-step methods for radiation chemistry simulations

    Science.gov (United States)

    Plante, Ianik; Devroye, Luc

    2017-10-01

    Ionizing radiation interacts with the water molecules of the tissues mostly by ionizations and excitations, which result in the formation of the radiation track structure and the creation of radiolytic species such as H.,.OH, H2, H2O2, and e-aq. After their creation, these species diffuse and may chemically react with the neighboring species and with the molecules of the medium. Therefore radiation chemistry is of great importance in radiation biology. As the chemical species are not distributed homogeneously, the use of conventional models of homogeneous reactions cannot completely describe the reaction kinetics of the particles. Actually, many simulations of radiation chemistry are done using the Independent Reaction Time (IRT) method, which is a very fast technique to calculate radiochemical yields but which do not calculate the positions of the radiolytic species as a function of time. Step-by-step (SBS) methods, which are able to provide such information, have been used only sparsely because these are time-consuming in terms of calculation. Recent improvements in computer performance now allow the regular use of the SBS method in radiation chemistry. The SBS and IRT methods are both based on the Green's functions of the diffusion equation (GFDE). In this paper, several sampling algorithms of the GFDE and for the IRT method are presented. We show that the IRT and SBS methods are exactly equivalent for 2-particles systems for diffusion and partially diffusion-controlled reactions between non-interacting particles. We also show that the results obtained with the SBS simulation method with periodic boundary conditions are in agreement with the predictions by classical reaction kinetics theory, which is an important step towards using this method for modelling of biochemical networks and metabolic pathways involved in oxidative stress. Finally, the first simulation results obtained with the code RITRACKS (Relativistic Ion Tracks) are presented.

  11. Solvents in Organic Synthesis: Replacement and Multi-step Reaction Systems

    DEFF Research Database (Denmark)

    Gani, Rafiqul; Gómez, Paola Arenas; Folic, Milica

    2008-01-01

    with the principles of green chemistry, highlight the need to minimize and optimize the use of organic solvents as much as possible. One important step in optimizing organic solvent use is the identification of suitable ‘greener' solvents that can help to minimize the environmental, health and safety concerns during...... solvent screening problem, several solvent replacement problems and a multi-stage reaction system. In each example a list of solvent candidates is generated so they may be further investigated experimentally....

  12. Classification of Chemical Reactions: Stages of Expertise

    Science.gov (United States)

    Stains, Marilyne; Talanquer, Vicente

    2008-01-01

    In this study we explore the strategies that undergraduate and graduate chemistry students use when engaged in classification tasks involving symbolic and microscopic (particulate) representations of different chemical reactions. We were specifically interested in characterizing the basic features to which students pay attention when classifying…

  13. Alternative statistics in multi-step direct reaction theory

    International Nuclear Information System (INIS)

    Koning, A.J.

    1990-06-01

    In recent years a variety of statistical theories have been developed concerning multistep direct (MSD) nuclear reactions. In addition, dominant in applications is a whole class of semiclassical models that may be subsumed under the heading of 'generalized exciton model': these are basically MSD-type extensions on top of compound-like concepts. In this report the relationship between their underlying statistical MSD-postulates are highlighted. A common framework is sketched that enables to generate the various MSD theories through assigning statistical properties to different parts of the nuclear Hamiltonian. Then it is shown that distinct forms of nuclear randomness are embodied in the mentioned theories. All these theories appear to be very similar at a qualitative level. In order to explain the high-energy tails and forward-peaked angular distribution typical for particles emitted in MSD reactions, it is imaged that the incident continuum particle stepwise looses its energy and direction in a sequence of collisions, thereby creating new particle-hole pairs in the target system. At each step emission may take place. The statistical aspect comes in because many continuum states are involved in the process. These are supposed to display chaotic behavior, the associated randomness assumption giving rise to important simplifications in the expressions for the MSD emission cross sections. This picture suggests that the mentioned MSD models can be interpreted as variants of essentially one and the same theory. However, this appears not to be the case. To show this the usual MSD distinction within the composite reacting nucleus between the fast continuum particle and the residual system is introduced. One implication is that the mutual residual interactions of the nucleons of the residual core are to be distinguished from those of the leading particle with the residual system. This distinction will turn out to be central to the present analysis. (author). 14 refs.; 4

  14. Theoretical intercomparison of multi-step direct reaction models and computational intercomparison of multi-step direct reaction models

    International Nuclear Information System (INIS)

    Koning, A.J.

    1992-08-01

    In recent years several statistical theories have been developed concerning multistep direct (MSD) nuclear reactions. In addition, dominant in applications is a whole class of semiclassical models that may be subsumed under the heading of 'generalized exciton models'. These are basically MSD-type extensions on top of compound-like concepts. In this report the relationship between their underlying statistical MSD-postulates is highlighted. A command framework is outlined that enables to generate the various MSD theories through assigning statistical properties to different parts of the nuclear Hamiltonian. Then it is shown that distinct forms of nuclear randomness are embodied in the mentioned theories. All these theories appear to be very similar at a qualitative level. In order to explain the high energy-tails and forward-peaked angular distribution typical for particles emitted in MSD reactions, it is imagined that the incident continuum particle stepwise looses its energy and direction in a sequence of collisions, thereby creating new particle-hole pairs in the target system. At each step emission may take place. The statistical aspect comes in because many continuum states are involved in the process. These are supposed to display chaotic behavior, the associated randomness assumption giving rise to important simplifications in the expression for MSD emission cross sections. This picture suggests that mentioned MSD models can be interpreted as a variant of essentially one and the same theory. However, this appears not to be the case. To show this usual MSD distinction within the composite reacting nucleus between the fast continuum particle and the residual interactions, the nucleons of the residual core are to be distinguished from those of the leading particle with the residual system. This distinction will turn out to be crucial to present analysis. 27 refs.; 5 figs.; 1 tab

  15. Iterative learning control for synchronization of reticle stage and wafer stage in step-and-scan lithographic equipment

    Science.gov (United States)

    Li, Lan-lan; Hu, Song; Zhao, Li-xin; Ma, Ping

    2013-08-01

    Lithographic equipments are highly complex machines used to manufacture integrated circuits (ICs). To make larger ICs, a larger lens is required, which, however, is prohibitively expensive. The solution to this problem is to expose a chip not in one flash but in a scanning fashion. For step-and-scan lithographic equipment (wafer scanner), the image quality is decided by many factors, in which synchronization of reticle stage and wafer stage during exposure is a key one. In this paper, the principle of reticle stage and wafer stage was analyzed through investigating the structure of scanners, firstly. While scanning, the reticle stage and wafer stage should scan simultaneously at a high speed and the speed ratio is 1:4. Secondly, an iterative learning controller (ILC) for synchronization of reticle stage and wafer stage is presented. In the controller, a master-slave structure is used, with the wafer stage acting as the master, and the reticle stage as the slave. Since the scanning process of scanner is repetitive, ILC is used to improve tracking performance. A simple design procedure is presented which allows design of the ILC system for the reticle stage and wafer stage independently. Finally, performance of the algorithm is illustrated by simulated on the virtual stages (the reticle stage and wafer stage).The results of simulation experiments and theory analyzing demonstrate that using the proposed controller better synchronization performance can be obtained for the reticle stage and wafer stage in scanner. Theory analysis and experiment shows the method is reasonable and efficient.

  16. Consumer adverse drug reaction reporting - A new step in pharmacovigilance?

    NARCIS (Netherlands)

    van Grootheest, K; de Graaf, L; de Jong-van den Berg, LTW

    2003-01-01

    The direct reporting of adverse drug reactions by patients is becoming an increasingly important topic for discussion in the world of pharmacovigilance. At this time, few countries accept consumer reports. We present an overview of experiences with consumer reporting in various countries of the

  17. Chemical kinetics of consecutive and parallel reactions both with a reversible first step

    International Nuclear Information System (INIS)

    Park, Tae Jun; Park, Bong Ser

    2015-01-01

    We solve the rate equations analytically for the first-order consecutive reaction and the corresponding parallel reaction both with a reversible first step. Results of the consecutive reaction, especially, can be used to determine explicitly the product concentration of the unimolecular decomposition and of the enzyme reaction which has hitherto been calculated by approximation. In addition, we indicate how we specify a certain reaction to be consecutive or parallel by comparing experimental data with theory. We also show that rate constants for the reactions are found from the various time derivatives of concentrations

  18. KAPSIES: A program for the calculation of multi-step direct reaction cross sections

    International Nuclear Information System (INIS)

    Koning, A.J.; Akkermans, J.M.

    1994-09-01

    We present a program for the calculation of continuum cross sections, sepctra, angular distributions and analyzing powers according to various quantum-mechanical theories for statistical multi-step direct nuclear reactions. (orig.)

  19. STEPS: Modeling and Simulating Complex Reaction-Diffusion Systems with Python

    OpenAIRE

    Wils, Stefan; Schutter, Erik De

    2009-01-01

    We describe how the use of the Python language improved the user interface of the program STEPS. STEPS is a simulation platform for modeling and stochastic simulation of coupled reaction-diffusion systems with complex 3-dimensional boundary conditions. Setting up such models is a complicated process that consists of many phases. Initial versions of STEPS relied on a static input format that did not cleanly separate these phases, limiting modelers in how they could control the simulation and b...

  20. Evaluation of high step-up power electronics stages in thermoelectric generator systems

    DEFF Research Database (Denmark)

    Sun, Kai; Ni, Longxian; Chen, Min

    2013-01-01

    To develop practical thermoelectric generator (TEG) systems, especially radioisotope thermoelectric power supplies for deep-space exploration, a power conditioning stage with high step-up gain is indispensable. This stage is used to step up the low output voltage of thermoelectric generators to t...... efficiency and input current ripples. The interleaved boost converter with an auxiliary transformer is found to be the most suitable topology for TEG applications, which is verified by experiments....... to the required high level. Furthermore, maximum power point tracking control for TEG modules needs to be implemented into the power electronics stages. In this paper, the temperature-dependent electrical characteristics of a thermoelectric generator are analyzed in depth. Three typical high step-up power...... converters suitable for TEG applications are discussed: an interleaved boost converter, a boost converter with a coupled inductor and an interleaved boost converter with an auxiliary transformer. A general comparison of the three high step-up converters is conducted to study the step-up gain, conversion...

  1. Women's steps of change and entry into drug abuse treatment. A multidimensional stages of change model.

    Science.gov (United States)

    Brown, V B; Melchior, L A; Panter, A T; Slaughter, R; Huba, G J

    2000-04-01

    The Transtheoretical, or Stages of Change Model, has been applied to the investigation of help-seeking related to a number of addictive behaviors. Overall, the model has shown to be very important in understanding the process of help-seeking. However, substance abuse rarely exists in isolation from other health, mental health, and social problems. The present work extends the original Stages of Change Model by proposing "Steps of Change" as they relate to entry into substance abuse treatment programs for women. Readiness to make life changes in four domains-domestic violence, HIV sexual risk behavior, substance abuse, and mental health-is examined in relation to entry into four substance abuse treatment modalities (12-step, detoxification, outpatient, and residential). The Steps of Change Model hypothesizes that help-seeking behavior of substance-abusing women may reflect a hierarchy of readiness based on the immediacy, or time urgency, of their treatment issues. For example, women in battering relationships may be ready to make changes to reduce their exposure to violence before admitting readiness to seek substance abuse treatment. The Steps of Change Model was examined in a sample of 451 women contacted through a substance abuse treatment-readiness program in Los Angeles, California. A series of logistic regression analyses predict entry into four separate treatment modalities that vary. Results suggest a multidimensional Stages of Change Model that may extend to other populations and to other types of help-seeking behaviors.

  2. An experimental and theoretical study of reaction steps relevant to the methanol-to-hydrocarbons reaction

    Energy Technology Data Exchange (ETDEWEB)

    Svelle, Stian

    2004-07-01

    The primary objective of the present work is to obtain new insight into the reaction mechanism of the zeolite catalyzed methanol-to-hydrocarbons (MTH) reaction. It was decided to use both experimental and computational techniques to reach this goal. An investigation of the n-butene + methanol system was therefore initiated. Over time, it became apparent that it was possible to determine the rate for the methylation of n-butene by methanol. The ethene and propene systems were therefore reexamined in order to collect kinetic information also for those cases. With the development of user-friendly quantum chemistry programs such as the Gaussian suite of programs, the possibility of applying quantum chemical methods to many types of problems has become readily available even for non-experts. When performing mechanistic studies, there is quite often a considerable synergy effect when combining experimental and computational approaches. The methylation reactions mentioned above turned out to be an issue well suited for quantum chemical investigations. The incentive for examining the halomethane reactivity was the clear analogy to the MTH reaction system. Alkene dimerization was also a reaction readily examined with quantum chemistry. As discussed in the introduction of this thesis, polymethylbenzenes, or their cationic counterparts, are suspected to be key intermediates in the MTH reaction. It was therefore decided to investigate the intrinsic reactivity of these species in the gas-phase by employing sophisticated mass spectrometric (MS) techniques in collaboration with the MS group at the Department of Chemistry, University of Oslo The data thus obtained will also be compared with results from an ongoing computational study on gas phase polymethylbenzenium reactivity. 6 papers presenting various studies are included. The titles are: 1) A Theoretical Investigation of the Methylation of Alkenes with Methanol over Acidic Zeolites. 2) A Theoretical Investigation of the

  3. Probing the Rate-Determining Step of the Claisen-Schmidt Condensation by Competition Reactions

    Science.gov (United States)

    Mak, Kendrew K. W.; Chan, Wing-Fat; Lung, Ka-Ying; Lam, Wai-Yee; Ng, Weng-Cheong; Lee, Siu-Fung

    2007-01-01

    Competition experiments are a useful tool for preliminary study of the linear free energy relationship of organic reactions. This article describes a physical organic experiment for upper-level undergraduates to identify the rate-determining step of the Claisen-Schmidt condensation of benzaldehyde and acetophenone by studying the linear free…

  4. Fast-ion energy resolution by one-step reaction gamma-ray spectrometry

    DEFF Research Database (Denmark)

    Salewski, Mirko; Nocente, M.; Gorini, G.

    2016-01-01

    The spectral broadening of γ-rays from fusion plasmas can be measured in high-resolution gamma-ray spectrometry (GRS). We derive weight functions that determine the observable velocity space and quantify the velocity-space sensitivity of one-step reaction high-resolution GRS measurements in magne...

  5. Modified Step Variational Iteration Method for Solving Fractional Biochemical Reaction Model

    Directory of Open Access Journals (Sweden)

    R. Yulita Molliq

    2011-01-01

    Full Text Available A new method called the modification of step variational iteration method (MoSVIM is introduced and used to solve the fractional biochemical reaction model. The MoSVIM uses general Lagrange multipliers for construction of the correction functional for the problems, and it runs by step approach, which is to divide the interval into subintervals with time step, and the solutions are obtained at each subinterval as well adopting a nonzero auxiliary parameter ℏ to control the convergence region of series' solutions. The MoSVIM yields an analytical solution of a rapidly convergent infinite power series with easily computable terms and produces a good approximate solution on enlarged intervals for solving the fractional biochemical reaction model. The accuracy of the results obtained is in a excellent agreement with the Adam Bashforth Moulton method (ABMM.

  6. A cascade reaction network mimicking the basic functional steps of acquired immune response

    Science.gov (United States)

    Han, Da; Wu, Cuichen; You, Mingxu; Zhang, Tao; Wan, Shuo; Chen, Tao; Qiu, Liping; Zheng, Zheng; Liang, Hao; Tan, Weihong

    2015-01-01

    Biological systems use complex ‘information processing cores’ composed of molecular networks to coordinate their external environment and internal states. An example of this is the acquired, or adaptive, immune system (AIS), which is composed of both humoral and cell-mediated components. Here we report the step-by-step construction of a prototype mimic of the AIS which we call Adaptive Immune Response Simulator (AIRS). DNA and enzymes are used as simple artificial analogues of the components of the AIS to create a system which responds to specific molecular stimuli in vitro. We show that this network of reactions can function in a manner which is superficially similar to the most basic responses of the vertebrate acquired immune system, including reaction sequences that mimic both humoral and cellular responses. As such, AIRS provides guidelines for the design and engineering of artificial reaction networks and molecular devices. PMID:26391084

  7. A cascade reaction network mimicking the basic functional steps of adaptive immune response.

    Science.gov (United States)

    Han, Da; Wu, Cuichen; You, Mingxu; Zhang, Tao; Wan, Shuo; Chen, Tao; Qiu, Liping; Zheng, Zheng; Liang, Hao; Tan, Weihong

    2015-10-01

    Biological systems use complex 'information-processing cores' composed of molecular networks to coordinate their external environment and internal states. An example of this is the acquired, or adaptive, immune system (AIS), which is composed of both humoral and cell-mediated components. Here we report the step-by-step construction of a prototype mimic of the AIS that we call an adaptive immune response simulator (AIRS). DNA and enzymes are used as simple artificial analogues of the components of the AIS to create a system that responds to specific molecular stimuli in vitro. We show that this network of reactions can function in a manner that is superficially similar to the most basic responses of the vertebrate AIS, including reaction sequences that mimic both humoral and cellular responses. As such, AIRS provides guidelines for the design and engineering of artificial reaction networks and molecular devices.

  8. Single-Stage Step up/down Driver for Permanent-Magnet Synchronous Machines

    Science.gov (United States)

    Chen, T. R.; Juan, Y. L.; Huang, C. Y.; Kuo, C. T.

    2017-11-01

    The two-stage circuit composed of a step up/down dc converter and a three-phase voltage source inverter is usually adopted as the electric vehicle’s motor driver. The conventional topology is more complicated. Additional power loss resulted from twice power conversion would also cause lower efficiency. A single-stage step up/down Permanent-Magnet Synchronous Motor driver for Brushless DC (BLDC) Motor is proposed in this study. The number components and circuit complexity are reduced. The low frequency six-step square-wave control is used to reduce the switching losses. In the proposed topology, only one active switch is gated with a high frequency PWM signal for adjusting the rotation speed. The rotor position signals are fed back to calculate the motor speed for digital close-loop control in a MCU. A 600W prototype circuit is constructed to drive a BLDC motor with rated speed 3000 rpm, and can control the speed of six sections.

  9. STEPS: modeling and simulating complex reaction-diffusion systems with Python

    Directory of Open Access Journals (Sweden)

    Stefan Wils

    2009-06-01

    Full Text Available We describe how the use of the Python language improved the user interface of the program STEPS. STEPS is a simulation platform for modeling and stochastic simulation of coupled reaction-diffusion systems with complex 3-dimensional boundary conditions. Setting up such models is a complicated process that consists of many phases. Initial versions of STEPS relied on a static input format that did not cleanly separate these phases, limiting modelers in how they could control the simulation and becoming increasingly complex as new features and new simulation algorithms were added. We solved all of these problems by tightly integrating STEPS with Python, using SWIG to expose our existing simulation code.

  10. Application of the balancing holes on the turbine stage discs with higher root reaction

    Directory of Open Access Journals (Sweden)

    Mrózek Lukáš

    2016-01-01

    Full Text Available The influence of the flow area of balancing holes in the discs of a steam turbine on its thermodynamic efficiency is examined for turbine stages operating in the increased root reaction regime. The interstage seal flooding with steam is modelled. The impact is given on stage reaction changes, on mass flow adjustments, and on overpressure operating in the rotor disc.

  11. Automated Discovery of Elementary Chemical Reaction Steps Using Freezing String and Berny Optimization Methods.

    Science.gov (United States)

    Suleimanov, Yury V; Green, William H

    2015-09-08

    We present a simple protocol which allows fully automated discovery of elementary chemical reaction steps using in cooperation double- and single-ended transition-state optimization algorithms--the freezing string and Berny optimization methods, respectively. To demonstrate the utility of the proposed approach, the reactivity of several single-molecule systems of combustion and atmospheric chemistry importance is investigated. The proposed algorithm allowed us to detect without any human intervention not only "known" reaction pathways, manually detected in the previous studies, but also new, previously "unknown", reaction pathways which involve significant atom rearrangements. We believe that applying such a systematic approach to elementary reaction path finding will greatly accelerate the discovery of new chemistry and will lead to more accurate computer simulations of various chemical processes.

  12. Field theoretical approach to proton-nucleus reactions. I - One step inelastic scattering

    International Nuclear Information System (INIS)

    Eiras, A.; Kodama, T.; Nemes, M.C.

    1988-01-01

    In this work we obtain a closed form expression to the double differential cross section for one step proton-nucleus reaction within a field theoretical framework. Energy and momentum conservation as well as nuclear structure effects are consistently taken into account within the field theoretical eikonal approximation. In our formulation the kinematics of such reaction is not dominated by the free nucleon-nucleon cross section but a new factor which we call relativistic differential cross section in a Born Approximation. (author) [pt

  13. Elderly fallers enhance dynamic stability through anticipatory postural adjustments during a choice stepping reaction time

    Directory of Open Access Journals (Sweden)

    Romain Tisserand

    2016-11-01

    Full Text Available In the case of disequilibrium, the capacity to step quickly is critical to avoid falling for elderly. This capacity can be simply assessed through the choice stepping reaction time test (CSRT, where elderly fallers (F take longer to step than elderly non-fallers (NF. However, reasons why elderly F elongate their stepping time remain unclear. The purpose of this study is to assess the characteristics of anticipated postural adjustments (APA that elderly F develop in a stepping context and their consequences on the dynamic stability. 44 community-dwelling elderly subjects (20 F and 22 NF performed a CSRT where kinematics and ground reaction forces were collected. Variables were analyzed using two-way repeated measures ANOVAs. Results for F compared to NF showed that stepping time is elongated, due to a longer APA phase. During APA, they seem to use two distinct balance strategies, depending on the axis: in the anteroposterior direction, we measured a smaller backward movement and slower peak velocity of the center of pressure (CoP; in the mediolateral direction, the CoP movement was similar in amplitude and peak velocity between groups but lasted longer. The biomechanical consequence of both strategies was an increased margin of stability (MoS at foot-off, in the respective direction. By elongating their APA, elderly F use a safer balance strategy that prioritizes dynamic stability conditions instead of the objective of the task. Such a choice in balance strategy probably comes from muscular limitations and/or a higher fear of falling and paradoxically indicates an increased risk of fall.

  14. Elderly Fallers Enhance Dynamic Stability Through Anticipatory Postural Adjustments during a Choice Stepping Reaction Time

    Science.gov (United States)

    Tisserand, Romain; Robert, Thomas; Chabaud, Pascal; Bonnefoy, Marc; Chèze, Laurence

    2016-01-01

    In the case of disequilibrium, the capacity to step quickly is critical to avoid falling in elderly. This capacity can be simply assessed through the choice stepping reaction time test (CSRT), where elderly fallers (F) take longer to step than elderly non-fallers (NF). However, the reasons why elderly F elongate their stepping time remain unclear. The purpose of this study is to assess the characteristics of anticipated postural adjustments (APA) that elderly F develop in a stepping context and their consequences on the dynamic stability. Forty-four community-dwelling elderly subjects (20 F and 24 NF) performed a CSRT where kinematics and ground reaction forces were collected. Variables were analyzed using two-way repeated measures ANOVAs. Results for F compared to NF showed that stepping time is elongated, due to a longer APA phase. During APA, they seem to use two distinct balance strategies, depending on the axis: in the anteroposterior direction, we measured a smaller backward movement and slower peak velocity of the center of pressure (CoP); in the mediolateral direction, the CoP movement was similar in amplitude and peak velocity between groups but lasted longer. The biomechanical consequence of both strategies was an increased margin of stability (MoS) at foot-off, in the respective direction. By elongating their APA, elderly F use a safer balance strategy that prioritizes dynamic stability conditions instead of the objective of the task. Such a choice in balance strategy probably comes from muscular limitations and/or a higher fear of falling and paradoxically indicates an increased risk of fall. PMID:27965561

  15. Plant Protochlorophyllide Oxidoreductases A and B: CATALYTIC EFFICIENCY AND INITIAL REACTION STEPS.

    Science.gov (United States)

    Garrone, Alessio; Archipowa, Nataliya; Zipfel, Peter F; Hermann, Gudrun; Dietzek, Benjamin

    2015-11-20

    The enzyme protochlorophyllide oxidoreductase (POR, EC 1.3.1.33) has a key role in plant development. It catalyzes one of the later steps in chlorophyll synthesis, the light-induced reduction of protochlorophyllide (PChlide) into chlorophyllide (Chlide) in the presence of NADPH. Two isozymes of plant POR, POR A and POR B from barley, which differ in their function during plant life, are compared with respect to their substrate binding affinity, catalytic efficiency, and catalytic mechanism. POR B as compared with POR A shows an 5-fold higher binding affinity for PChlide and an about 6-fold higher catalytic efficiency measured as kcat/Km. Based on the reaction intermediates, which can be trapped at low temperatures the same reaction mechanism operates in both POR A and POR B. In contrast to results reported for POR enzymes from cyanobacteria, the initial light-driven step, which occurs at temperatures below 180 K already involves the full chemistry of the photoreduction and yields the reaction product, Chlide, in an enzyme-bound form. The subsequent dark reactions, which include cofactor (NADP(+)) release and cofactor (NADPH) rebinding, show different temperature dependences for POR A and POR B and suggest a higher conformational flexibility of POR B in the surrounding active center. Both the higher substrate binding affinity and well adapted enzyme dynamics are held responsible for the increased catalytic activity of POR B as compared with POR A. © 2015 by The American Society for Biochemistry and Molecular Biology, Inc.

  16. A Semi-Empirical Two Step Carbon Corrosion Reaction Model in PEM Fuel Cells

    Energy Technology Data Exchange (ETDEWEB)

    Young, Alan; Colbow, Vesna; Harvey, David; Rogers, Erin; Wessel, Silvia

    2013-01-01

    The cathode CL of a polymer electrolyte membrane fuel cell (PEMFC) was exposed to high potentials, 1.0 to 1.4 V versus a reversible hydrogen electrode (RHE), that are typically encountered during start up/shut down operation. While both platinum dissolution and carbon corrosion occurred, the carbon corrosion effects were isolated and modeled. The presented model separates the carbon corrosion process into two reaction steps; (1) oxidation of the carbon surface to carbon-oxygen groups, and (2) further corrosion of the oxidized surface to carbon dioxide/monoxide. To oxidize and corrode the cathode catalyst carbon support, the CL was subjected to an accelerated stress test cycled the potential from 0.6 VRHE to an upper potential limit (UPL) ranging from 0.9 to 1.4 VRHE at varying dwell times. The reaction rate constants and specific capacitances of carbon and platinum were fitted by evaluating the double layer capacitance (Cdl) trends. Carbon surface oxidation increased the Cdl due to increased specific capacitance for carbon surfaces with carbon-oxygen groups, while the second corrosion reaction decreased the Cdl due to loss of the overall carbon surface area. The first oxidation step differed between carbon types, while both reaction rate constants were found to have a dependency on UPL, temperature, and gas relative humidity.

  17. Mass-driver reaction engine as Shuttle upper-stage

    Science.gov (United States)

    Oneill, G. K.

    1977-01-01

    Optimization has been carried out on the design of a mass-driver intended for upgrading the Shuttle to geosynchronous and lunar-orbit capability. The machine accelerates 2,100 tons/yr of external tankage, in 14-gram segments, to exhaust velocities of 8,000-10,000 m/s. The resulting reaction force raises 1,700 tons/yr. of Shuttle payloads to high orbit, in two round trips. Exhaust velocity and thrust can be optimized for each mission segment. For a mission requiring an exhaust velocity of 8,000 m/sec, thrust is 560 newtons, power is 2.9 megawatts, and efficiency is 75%. Total electrical component mass including power supplies and waste-heat radiators is 89 tons. To insure that reaction mass does not constitute a hazard, segments may be in the form of powder, electrostatically dispersed after acceleration, and/or thrust may be vectored.

  18. Theory of Square-Wave Voltammetry of Two-Step Electrode Reaction Using an Inverse Scan Direction

    OpenAIRE

    Lovrić, Milivoj; Komorsky-Lovrić, Šebojka

    2011-01-01

    A theory of square-wave voltammetry of two-step electrode reaction with kinetically controlled electron transfers is developed, and a special case of thermodynamically unstable intermediate is analyzed. If the first reaction step is reversible and the second one is quasireversible, the response splits into two peaks if the scan direction is inverted. The separation of these peaks increases with frequency.

  19. Tonic ocular tilt reaction simulating a superior oblique palsy: diagnostic confusion with the 3-step test.

    Science.gov (United States)

    Donahue, S P; Lavin, P J; Hamed, L M

    1999-03-01

    The tonic ocular tilt reaction (OTR) consists of vertical divergence of the eyes (skew deviation), bilateral conjugate ocular torsion, and paradoxical head tilt. The head and superior pole of both eyes are rotated toward the hypotropic eye. To describe ocular motility and torsion findings in 5 patients with OTRs that mimicked superior oblique palsies (SOPs). In 5 patients, results of the 3-step test suggested an SOP (bilateral in 1 patient); however, no patient had the expected excyclotorsion of the hypertropic eye. Two patients had conjugate ocular torsion (intorsion of the hypertropic eye and extorsion of the hypotropic eye), and 2 patients had only intorsion of the hypertropic eye. All had other neurologic features consistent with more widespread brainstem disease. Vertical ocular deviations that 3-step to an SOP are not always caused by fourth nerve weakness. When a patient with an apparent fourth nerve palsy has ocular torsion that is inconsistent with an SOP, OTR should be suspected, especially if vestibular system or posterior fossa dysfunction coexists. The rules for the 3-step test for an SOP may be fulfilled by damaging the otolithic projections corresponding to projections of the contralateral anterior semicircular canal. Because results of the Bielschowsky head tilt test may be positive in patients with the OTR, the feature distinguishing OTR from an SOP is the direction of torsion. We advocate use of a fourth step-evaluation of ocular torsion-in addition to the standard 3 steps.

  20. Low cost optical tweezers systems using double coil driving stepping motor to controlling sample stage

    Science.gov (United States)

    Laowattanatham, N.; Cheamanunkul, N.; Plaipichit, S.; Buranasiri, P.; Nuansri, R.

    2013-06-01

    In this research, the low cost optical tweezers systems using X-Y stage has been developed by using 5-phase stepping motor. By using sequential double coil driving, we can obtain the driving torque larger than using the single coil driving. The moving scale is fine resolution at 0.2 micrometer. The overall systems based on microcontroller PIC18F458 and joystick controller with LabView® graphical user interface (GUI). The mechanical damping has been included in the system for decreasing the vibrational noise. By using this method, our optical tweezers system is cheaper than the other commercial system that has been used the piezoelectric driving, and still has the same efficiency.

  1. Growth of Fullerene Fragments Using the Diels-Alder Cycloaddition Reaction: First Step towards a C60 Synthesis by Dimerization

    Directory of Open Access Journals (Sweden)

    Julio A. Alonso

    2013-02-01

    Full Text Available Density Functional Theory has been used to model the Diels-Alder reactions of the fullerene fragments triindenetriphenilene and pentacyclopentacorannulene with ethylene and 1,3-butadiene. The purpose is to prove the feasibility of using Diels-Alder cycloaddition reactions to grow fullerene fragments step by step, and to dimerize fullerene fragments, as a way to obtain C60. The dienophile character of the fullerene fragments is dominant, and the reaction of butadiene with pentacyclopentacorannulene is favored.

  2. A model of hydrogen impact induced chemical erosion of carbon based on elementary reaction steps

    International Nuclear Information System (INIS)

    Wittmann, M.; Kueppers, J.

    1996-01-01

    Based on the elementary reaction steps for chemical erosion of carbon by hydrogen a model is developed which allows to calculate the amount of carbon erosion at a hydrogenated carbon surface under the impact of hydrogen ions and neutrals. Hydrogen ion and neutral flux energy distributions prevailing at target plates in the ASDEX upgrade experiment are chosen in the present calculation. The range of hydrogen particles in the target plates is calculated using TRIDYN code. Based upon the TRIDYN results the extent of the erosion reaction as a function of depth is estimated. The results show that both, target temperature and impinging particle flux energy distribution, determine the hydrogen flux density dependent erosion yield and the location of the erosion below the surface. (orig.)

  3. Evaluating the fall risk among elderly population by choice step reaction test

    Directory of Open Access Journals (Sweden)

    Wang D

    2016-08-01

    Full Text Available Donghai Wang,1 Jian Zhang,1 Yuliang Sun,2 Wenfei Zhu,2 Shiliu Tian,1 Yu Liu1 1Key Laboratory of Exercise and Health Sciences of the Ministry of Education, Shanghai University of Sport, Shanghai, People’s Republic of China; 2School of Physical Education, Shaanxi Normal University, Xian, People’s Republic of China Abstract: Falls during daily activities are often associated with injuries and physical disabilities, thereby affecting quality of life among elder adults. Balance control, which is crucial in avoiding falls, is composed of two elements: muscle strength and central nervous system (CNS control. A number of studies have reported that reduced muscle strength raises the risk of falling. However, to date there has been only limited research focused on the relationship between fall risk and the CNS. This study aimed to investigate the relationship between CNS and risk of falling among the elderly. A total of 140 elderly people (92 females and 48 males were divided into faller and nonfaller groups based on questionnaire responses concerning falls in their daily life. Participants undertook a choice step reaction test in which they were required to respond to random visual stimuli using foot movements as fast as possible in the left or right directions. Response time was quantified as premotor time (PMT and motor time (MT. In addition, the participants’ electromyography data were recorded during the choice step reaction test. A maximal isokinetic torque test was also performed. PMT was greater in the fallers than in the nonfallers group. There was a significant difference between fall status and direction on PMT. PMT of the left limb in nonfallers was faster than the right, but in fallers there was no difference between left and right limbs. A similar phenomenon was also observed for MT. There were significant differences between fallers and nonfallers in maximum isokinetic torque at knee and ankle joints. The correct rate of PMT was

  4. Spiro annulation of cage polycycles via Grignard reaction and ring-closing metathesis as key steps

    Directory of Open Access Journals (Sweden)

    Sambasivarao Kotha

    2015-08-01

    Full Text Available A simple synthetic strategy to C2-symmetric bis-spiro-pyrano cage compound 7 involving ring-closing metathesis is reported. The hexacyclic dione 10 was prepared from simple and readily available starting materials such as 1,4-naphthoquinone and cyclopentadiene. The synthesis of an unprecedented octacyclic cage compound through intramolecular Diels–Alder (DA reaction as a key step is described. The structures of three new cage compounds 7, 12 and 18 were confirmed by single crystal X-ray diffraction studies.

  5. Stabilization of miscible viscous fingering by a step-growth polymerization reaction

    Science.gov (United States)

    Bunton, Patrick; Stewart, Simone; Marin, Daniela; Tullier, Michael; Meiburg, Eckart; Pojman, John

    2017-11-01

    Viscous fingering is a hydrodynamic instability that occurs when a more mobile fluid displaces a fluid of lower mobility. Viscous fingering is often undesirable in industrial processes such as secondary petroleum recovery where it limits resource recovery. Linear stability analysis by Hejazi et al. (2010) has predicted that a non-monotonic viscosity profile at an otherwise unstable interface can in some instances stabilize the flow. We use step-growth polymerization at the interface between two miscible monomers as a model system. A dithiol monomer displacing a diacrylate react to form a linear polymer that behaves as a Newtonian fluid. Viscous fingering was imaged in a horizontal Hele-Shaw cell via Schlieren, which is sensitive to polymer conversion. By varying reaction rate via initiator concentration along with flow rate, we demonstrated increasing stabilization of the flow with increasing Damkohler number (ratio of the reaction rate to the flow rate). Results were compared with regions of predicted stability from the results of Hejazi et al. (2010). When the advection outran the reaction, viscous fingering occurred as usual. However, when the reaction was able to keep pace with the advection, the increased viscosity at the interface stabilized the flow. We acknowledge support from NSF CBET-1335739 and NSF CBET 1511653.

  6. Stimulant Abuser Groups to Engage in 12-Step (STAGE-12): A Multisite Trial in the NIDA Clinical Trials Network

    Science.gov (United States)

    Donovan, Dennis M.; Daley, Dennis C.; Brigham, Gregory S.; Hodgkins, Candace C.; Perl, Harold I.; Garrett, Sharon; Doyle, Suzanne; Floyd, Anthony S.; Knox, Patricia C.; Botero, Christopher; Kelly, Thomas; Killeen, Therese; Hayes, Carole; Baumhofer, Nicole Kau’i; Seamans, Cindy; Zammarelli, Lucy

    2012-01-01

    Aims The study evaluated the effectiveness of an 8-week combined group plus individual 12-step facilitative intervention on stimulant drug use and 12-step meeting attendance and service. Design Multisite randomized controlled trial, with assessments at baseline, mid-treatment, end of treatment, and 3- and 6-month post-randomization follow-ups (FU). Setting Intensive outpatient substance treatment programs. Participants Individuals with stimulant use disorders (n = 471) randomly assigned to treatment as usual (TAU) or TAU into which the STAGE-12 intervention was integrated. Measurements Urinalysis and self-reports of substance use and 12-step attendance and activities. Intervention Group sessions focused on increasing acceptance of 12-step principles; individual sessions incorporated an intensive referral procedure connecting participants to 12-step volunteers. Findings Compared to TAU, STAGE-12 participants had significantly greater odds of self-reported stimulant abstinence during the active 8-week treatment phase; however, among those who had not achieved abstinence during this period, STAGE-12 participants had more days of use. STAGE-12 participants had lower ASI Drug Composite scores at and a significant reduction from baseline to the 3-month FU, attended 12-step meetings on a greater number of days during the early phase of active treatment, engaged in more other types of 12-step activities throughout the active treatment phase and the entire FU period, and had more days of self-reported service at meetings from mid-treatment through the 6-month FU. Conclusions The present findings are mixed with respect to the impact of integrating the STAGE-12 intervention into intensive outpatient drug treatment compared to TAU on stimulant drug use. However, the results more clearly indicate that individuals in STAGE-12 had higher rates of 12-step meeting attendance and were engaged in more related activities throughout both the active treatment phase and the entire 6

  7. BILATERAL GROUND REACTION FORCES AND JOINT MOMENTS FOR LATERAL SIDESTEPPING AND CROSSOVER STEPPING TASKS

    Directory of Open Access Journals (Sweden)

    William I. Sellers

    2009-03-01

    Full Text Available Racquet sports have high levels of joint injuries suggesting the joint loads during play may be excessive. Sports such as badminton employ lateral sidestepping (SS and crossover stepping (XS movements which so far have not been described in terms of biomechanics. This study examined bilateral ground reaction forces and three dimensional joint kinetics for both these gaits in order to determine the demands of the movements on the leading and trailing limb and predict the contribution of these movements to the occurrence of overuse injury of the lower limbs. A force platform and motion-analysis system were used to record ground reaction forces and track marker trajectories of 9 experienced male badminton players performing lateral SS, XS and forward running tasks at a controlled speed of 3 m·s-1 using their normal technique. Ground reaction force and kinetic data for the hip, knee and ankle were analyzed, averaged across the group and the biomechanical variables compared. In all cases the ground reaction forces and joint moments were less than those experienced during moderate running suggesting that in normal play SS and XS gaits do not lead to high forces that could contribute to increased injury risk. Ground reaction forces during SS and XS do not appear to contribute to the development of overuse injury. The distinct roles of the leading and trailing limb, acting as a generator of vertical force and shock absorber respectively, during the SS and XS may however contribute to the development of muscular imbalances which may ultimately contribute to the development of overuse injury. However it is still possible that faulty use of these gaits might lead to high loads and this should be the subject of future work

  8. Benzoylformate analogues exhibit differential rate-determining steps in the benzoylformate decarboxylase reaction

    International Nuclear Information System (INIS)

    Garcia, G.A.; Weiss, P.M.; Cook, P.F.; Kenyon, G.L.; Cleland, W.W.

    1987-01-01

    Benzoylformate decarboxylase from Pseudomonas putida is a thiamine pyrophosphate (TPP)-dependent enzyme which converts benzoylformate to benzaldehyde and CO 2 . The rate-determining step(s) in the benzoylformate decarboxylase reaction for a series of substituted benzoylformates (p-CH 3 O, p-CH 3 , p-Cl, and m-F) were studied using solvent deuterium and 13 C kinetic isotope effects. The normal substrate was found to have two partially rate-determining steps; initial tetrahedral adduct formation (D 2 O-sensitive) and decarboxylation ( 13 C-sensitive). D 2 O and 13 C isotope effects indicate that electron-withdrawing substituents (p-Cl and m-F) remove the rate dependence upon decarboxylation such that only a D 2 O effect on (V/K) is observed. Conversely, electron-donating substituents increase the rate-dependence upon decarboxylation such that a larger 13 (V/K) is seen while the D 2 O effects on (V) and (V/K) are not dramatically different from those for benzoylformate. All of the data are consistent with substituent stabilization or destabilization of the carbanionic intermediate formed upon decarboxylation

  9. One step gold (bio)functionalisation based on CS{sub 2}-amine reaction

    Energy Technology Data Exchange (ETDEWEB)

    Almeida, Ines [Centro de Quimica e Bioquimica, Faculdade de Ciencias da Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016 Lisboa (Portugal); Cascalheira, Antonio C. [Lumisense, Lda, Campus Faculdade de Ciencias da Universidade de Lisboa, Ed. ICAT, Campo Grande, 1749-016 Lisboa (Portugal); Viana, Ana S., E-mail: anaviana@fc.ul.p [Centro de Quimica e Bioquimica, Faculdade de Ciencias da Universidade de Lisboa, Ed. C8, Campo Grande, 1749-016 Lisboa (Portugal)

    2010-12-01

    Dithiocarbamates have been regarded as alternative anchor groups to thiols on gold surfaces, and claimed to be formed in situ through the reaction between secondary amines and carbon disulphide. In this paper, we further exploit this methodology for a convenient one step biomolecule immobilisation onto gold surfaces. First, the reactivity between CS{sub 2} and electroactive compounds containing amines, primary (dopamine), secondary (epinephrine), and an amino acid (tryptophan) has been investigated by electrochemical methods. Cyclic voltammetric characterisation of the modified electrodes confirmed the immobilisation of all the target compounds, allowing the estimation of their surface concentration. The best result was obtained with epinephrine, a secondary amine, for which a typical quasi-reversible behaviour of surface confined electroactive species could be clearly depicted. Electrochemical reductive desorption studies enabled to infer on the extent of the reaction and on the relative stability of the generated monolayers. Bio-functionalisation studies have been accomplished through the reaction of CS{sub 2} with glucose oxidase in aqueous medium, and the catalytic activity of the immobilised enzyme was evaluated towards glucose, by electrochemical methods in the presence of a redox mediator. Scanning tunnelling microscopy (STM) and Atomic force microscopy (AFM) were used respectively, to characterize the gold electrodes and Glucose Oxidase coverage and distribution on the modified surfaces.

  10. Theory of Square-Wave Voltammetry of Two-Step Electrode Reaction Using an Inverse Scan Direction

    Directory of Open Access Journals (Sweden)

    Milivoj Lovrić

    2011-01-01

    Full Text Available A theory of square-wave voltammetry of two-step electrode reaction with kinetically controlled electron transfers is developed, and a special case of thermodynamically unstable intermediate is analyzed. If the first reaction step is reversible and the second one is quasireversible, the response splits into two peaks if the scan direction is inverted. The separation of these peaks increases with frequency.

  11. Velocity-space observation regions of high-resolution two-step reaction gamma-ray spectroscopy

    DEFF Research Database (Denmark)

    Salewski, Mirko; Nocente, M.; Gorini, G.

    2015-01-01

    High-resolution γ-ray spectroscopy (GRS) measurements resolve spectral shapes of Dopplerbroadened γ-rays. We calculate weight functions describing velocity-space sensitivities of any two-step reaction GRS measurements in magnetized plasmas using the resonant nuclear reaction 9Be(α, nγ)12C...

  12. The reaction rate for dissociative adsorption of N-2 on stepped Ru(0001): Six-dimensional quantum calculations

    DEFF Research Database (Denmark)

    van Harrevelt, Rob; Honkala, Johanna Karoliina; Nørskov, Jens Kehlet

    2005-01-01

    Quantum-mechanical calculations of the reaction rate for dissociative adsorption of N-2 on stepped Ru(0001) are presented. Converged six-dimensional quantum calculations for this heavy-atom reaction have been performed using the multiconfiguration time-dependent Hartree method. A potential...

  13. Effect of one step KOH activation and CaO modified carbon in transesterification reaction

    Science.gov (United States)

    Yacob, Abd Rahim; Zaki, Muhammad Azam Muhammad

    2017-11-01

    In this work, one step activation was introduced using potassium hydroxide (KOH) and calcium oxide (CaO) modified palm kernel shells. Various concentration of calcium oxide was used as catalyst while maintaining the same concentration of potassium hydroxide to activate and impregnate the palm kernel shell before calcined at 500°C for 5 hours. All the prepared samples were characterized using Fourier Transform Infrared (FTIR) and Field Emission Scanning Electron Microscope (FESEM). FTIR analysis of raw palm kernel shell showed the presence of various functional groups. However, after activation, most of the functional groups were eliminated. The basic strength of the prepared samples were determined using back titration method. The samples were then used as base heterogeneous catalyst for the transesterification reaction of rice bran oil with methanol. Analysis of the products were performed using Gas Chromatography Flame Ionization Detector (GC-FID) to calculate the percentage conversion of the biodiesel products. This study shows, as the percentage of one step activation potassium and calcium oxide doped carbon increases thus, the basic strength also increases followed by the increase in biodiesel production. Optimization study shows that the optimum biodiesel production was at 8 wt% catalyst loading, 9:1 methanol: oil molar ratio at 65°C and 6 hours which gives a conversion up to 95%.

  14. Elementary Steps of Syngas Reactions on Mo2C(001): Adsorption Thermochemistry and Bond Dissociation

    Energy Technology Data Exchange (ETDEWEB)

    Medford, Andrew

    2012-02-16

    Density functional theory (DFT) and ab initio thermodynamics are applied in order to investigate the most stable surface and subsurface terminations of Mo{sub 2}C(001) as a function of chemical potential and in the presence of syngas. The Mo-terminated (001) surface is then used as a model surface to evaluate the thermochemistry and energetic barriers for key elementary steps in syngas reactions. Adsorption energy scaling relations and Broensted-Evans-Polanyi relationships are established and used to place Mo{sub 2}C into the context of transition metal surfaces. The results indicate that the surface termination is a complex function of reaction conditions and kinetics. It is predicted that the surface will be covered by either C{sub 2}H{sub 2} or O depending on conditions. Comparisons to transition metals indicate that the Mo-terminated Mo{sub 2}C(001) surface exhibits carbon reactivity similar to transition metals such as Ru and Ir, but is significantly more reactive towards oxygen.

  15. Structural integration of separation and reaction systems: I. Integration of stage-wise processes

    Directory of Open Access Journals (Sweden)

    Mitrović Milan

    2002-01-01

    Full Text Available The structural integration of separation processes, using multifunctional equipment, has been studied on four stage-wise liquid-liquid separations extraction, absorption, distillation, adsorption and on some combinations of these processes. It was shown for stage - wise processes that the ultimate aim of equipment integration is 3-way integration (by components by steps and by stages and that membrane multiphase contactors present concerning the equipment optimal solutions in many cases. First, by using partially integrated equipment and, later by developing fully integrated systems it was experimentally confirmed that structural 3-way integration produces much higher degrees of component separations and component enrichments in compact and safe equipment.

  16. Step-by-Step Simulation of Radiation of Radiation Chemistry Using Green Functions for Diffusion-Influenced Reactions

    Science.gov (United States)

    Plante, Ianik; Cucinotta, Francis A.

    2011-01-01

    The irradiation of biological systems leads to the formation of radiolytic species such as H(raised dot), (raised dot)OH, H2, H2O2, e(sup -)(sub aq), etc.[1]. These species react with neighboring molecules, which result in damage in biological molecules such as DNA. Radiation chemistry is there for every important to understand the radiobiological consequences of radiation[2]. In this work, we discuss an approach based on the exact Green Functions for diffusion-influenced reactions which may be used to simulate radiation chemistry and eventually extended to study more complex systems, including DNA.

  17. Step-by-step guide to building an inexpensive 3D printed motorized positioning stage for automated high-content screening microscopy.

    Science.gov (United States)

    Schneidereit, Dominik; Kraus, Larissa; Meier, Jochen C; Friedrich, Oliver; Gilbert, Daniel F

    2017-06-15

    High-content screening microscopy relies on automation infrastructure that is typically proprietary, non-customizable, costly and requires a high level of skill to use and maintain. The increasing availability of rapid prototyping technology makes it possible to quickly engineer alternatives to conventional automation infrastructure that are low-cost and user-friendly. Here, we describe a 3D printed inexpensive open source and scalable motorized positioning stage for automated high-content screening microscopy and provide detailed step-by-step instructions to re-building the device, including a comprehensive parts list, 3D design files in STEP (Standard for the Exchange of Product model data) and STL (Standard Tessellation Language) format, electronic circuits and wiring diagrams as well as software code. System assembly including 3D printing requires approx. 30h. The fully assembled device is light-weight (1.1kg), small (33×20×8cm) and extremely low-cost (approx. EUR 250). We describe positioning characteristics of the stage, including spatial resolution, accuracy and repeatability, compare imaging data generated with our device to data obtained using a commercially available microplate reader, demonstrate its suitability to high-content microscopy in 96-well high-throughput screening format and validate its applicability to automated functional Cl - - and Ca 2+ -imaging with recombinant HEK293 cells as a model system. A time-lapse video of the stage during operation and as part of a custom assembled screening robot can be found at https://vimeo.com/158813199. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

  18. A simple procedure eliminating multiple optimization steps required in developing multiplex PCR reactions

    Energy Technology Data Exchange (ETDEWEB)

    Grondin, V.; Roskey, M.; Klinger, K.; Shuber, T. [Integrated Genetics, Framingham, MA (United States)

    1994-09-01

    The PCR technique is one of the most powerful tools in modern molecular genetics and has achieved widespread use in the analysis of genetic diseases. Typically, a region of interest is amplified from genomic DNA or cDNA and examined by various methods of analysis for mutations or polymorphisms. In cases of small genes and transcripts, amplification of single, small regions of DNA are sufficient for analysis. However, when analyzing large genes and transcripts, multiple PCRs may be required to identify the specific mutation or polymorphism of interest. Ever since it has been shown that PCR could simultaneously amplify multiple loci in the human dystrophin gene, multiplex PCR has been established as a general technique. The properities of multiplex PCR make it a useful tool and preferable to simultaneous uniplex PCR in many instances. However, the steps for developing a multiplex PCR can be laborious, with significant difficulty in achieving equimolar amounts of several different amplicons. We have developed a simple method of primer design that has enabled us to eliminate a number of the standard optimization steps required in developing a multiplex PCR. Sequence-specific oligonucleotide pairs were synthesized for the simultaneous amplification of multiple exons within the CFTR gene. A common non-complementary 20 nucleotide sequence was attached to each primer, thus creating a mixture of primer pairs all containing a universal primer sequence. Multiplex PCR reactions were carried out containing target DNA, a mixture of several chimeric primer pairs and primers complementary to only the universal portion of the chimeric primers. Following optimization of conditions for the universal primer, limited optimization was needed for successful multiplex PCR. In contrast, significant optimization of the PCR conditions were needed when pairs of sequence specific primers were used together without the universal sequence.

  19. Complex supramolecular interfacial tessellation through convergent multi-step reaction of a dissymmetric simple organic precursor

    Science.gov (United States)

    Zhang, Yi-Qi; Paszkiewicz, Mateusz; Du, Ping; Zhang, Liding; Lin, Tao; Chen, Zhi; Klyatskaya, Svetlana; Ruben, Mario; Seitsonen, Ari P.; Barth, Johannes V.; Klappenberger, Florian

    2018-03-01

    Interfacial supramolecular self-assembly represents a powerful tool for constructing regular and quasicrystalline materials. In particular, complex two-dimensional molecular tessellations, such as semi-regular Archimedean tilings with regular polygons, promise unique properties related to their nontrivial structures. However, their formation is challenging, because current methods are largely limited to the direct assembly of precursors, that is, where structure formation relies on molecular interactions without using chemical transformations. Here, we have chosen ethynyl-iodophenanthrene (which features dissymmetry in both geometry and reactivity) as a single starting precursor to generate the rare semi-regular (3.4.6.4) Archimedean tiling with long-range order on an atomically flat substrate through a multi-step reaction. Intriguingly, the individual chemical transformations converge to form a symmetric alkynyl-Ag-alkynyl complex as the new tecton in high yields. Using a combination of microscopy and X-ray spectroscopy tools, as well as computational modelling, we show that in situ generated catalytic Ag complexes mediate the tecton conversion.

  20. Metal-Ion- and Hydrogen-Bond-Mediated Interstellar Prebiotic Chemistry: The First Step in the Formose Reaction.

    Science.gov (United States)

    Thripati, Sorakayala; Ramabhadran, Raghunath O

    2017-11-16

    The formose reaction, which offers a feasible chemical pathway for the prebiotic synthesis of sugars, is a well-studied reaction for over two hundred and 50 years. Yet huge knowledge gaps exist even in the very first step of the formose reaction. In this work, we provide a new and otherwise unintuitive reaction pathway for the gas-phase conversion of formaldehyde to glycolaldehyde (the first step in the formose reaction) occurring in the interstellar medium (ISM). Employing electronic structure calculations (CCSD(T) and DFT methods), we exhaustively probe the role of various metal ions and small molecules detected in the ISM to propose a new mechanism wherein metal-oxygen interactions and hydrogen bonds cooperatively facilitate an otherwise implausible chemical reaction. The reactions involving Mg 2+ are throughout found to be barrierless, and those featuring Al + ions are noted to only have a small barrier. The proton affinities of the small molecules, metal-oxygen interactions, and the extent of C-C-bond formation are found to be the significant factors that influence the barrier heights. The mechanism is also shown to be consistent with well-known experimental details in the terrestrial formose reaction (which could, however, proceed through a different mechanism). Future experimental and theoretical scope arising out of this paper are subsequently discussed.

  1. Estimating reaction rate constants from a two-step reaction: a comparison between two-way and three-way methods

    NARCIS (Netherlands)

    Bijlsma, S.; Smilde, A. K.

    2000-01-01

    In this paper, two different spectral datasets are used in order to estimate reaction rate constants using different algorithms. Dataset 1 consists of short-wavelength near-infrared (SW NIR) spectra taken in time of the two-step epoxidation of 2,5-di-tert-butyl-1,4-benzoquinone using tert-butyl

  2. Mass transfer with complex chemical reactions in gas-liquid systems: two-step reversible reactions with unit stoichiometric and kinetic orders

    NARCIS (Netherlands)

    Vas bhat, R.D.; Kuipers, J.A.M.; Versteeg, Geert

    2000-01-01

    An absorption model to study gas¿liquid mass transfer accompanied by reversible two-step reactions in the liquid phase has been presented. This model has been used to determine mass transfer rates, enhancement factors and concentration profiles over a wide range of process conditions. Although

  3. Mass transfer with complex chemical reactions in gas–liquid systems : two-step reversible reactions with unit stoichiometric and kinetic orders

    NARCIS (Netherlands)

    Vas Bhat, R.D.; Kuipers, J.A.M.; Versteeg, G.F.

    2000-01-01

    An absorption model to study gas–liquid mass transfer accompanied by reversible two-step reactions in the liquid phase has been presented. This model has been used to determine mass transfer rates, enhancement factors and concentration profiles over a wide range of process conditions. Although

  4. Reaction Time Is Negatively Associated with Corpus Callosum Area in the Early Stages of CADASIL.

    Science.gov (United States)

    Delorme, S; De Guio, F; Reyes, S; Jabouley, A; Chabriat, H; Jouvent, E

    2017-11-01

    Reaction time was recently recognized as a marker of subtle cognitive and behavioral alterations in the early clinical stages of CADASIL, a monogenic cerebral small-vessel disease. In unselected patients with CADASIL, brain atrophy and lacunes are the main imaging correlates of disease severity, but MR imaging correlates of reaction time in mildly affected patients are unknown. We hypothesized that reaction time is independently associated with the corpus callosum area in the early clinical stages of CADASIL. Twenty-six patients with CADASIL without dementia (Mini-Mental State Examination score > 24 and no cognitive symptoms) and without disability (modified Rankin Scale score ≤ 1) were compared with 29 age- and sex-matched controls. Corpus callosum area was determined on 3D-T1 MR imaging sequences with validated methodology. Between-group comparisons were performed with t tests or χ 2 tests when appropriate. Relationships between reaction time and corpus callosum area were tested using linear regression modeling. Reaction time was significantly related to corpus callosum area in patients (estimate = -7.4 × 10 3 , standard error = 3.3 × 10 3 , P = .03) even after adjustment for age, sex, level of education, and scores of depression and apathy (estimate = -12.2 × 10 3 , standard error = 3.8 × 10 3 , P = .005). No significant relationship was observed in controls. Corpus callosum area, a simple and robust imaging parameter, appears to be an independent correlate of reaction time at the early clinical stages of CADASIL. Further studies will determine whether corpus callosum area can be used as an outcome in future clinical trials in CADASIL or in more prevalent small-vessel diseases. © 2017 by American Journal of Neuroradiology.

  5. [Study of ATP-independent stages of reaction catalyzed by phage T4 RNA-ligase].

    Science.gov (United States)

    Zagrebel'nyĭ, S N; Zernov, Iu P

    1986-01-01

    The isotope exchange between [5'-32P]pAP and A(5')ppAp catalyzed by enzyme was shown not to take place in the absence of the acceptor; i. e. the necessity of the acceptor presence during the second step of the process was demonstrated. The isotope exchange reaction between [5'32P]pAp and (pA)5p was studied. It was demonstrated that acceptor (pA)4, slightly whereas the acceptor (pU)4 completely inhibits the isotope reaction. The isotope reaction exchange between [5'-32P]pAp and (pU)4pAp does not take place. The question of existence of adenylated donor elimination mechanism in the presence of "poor" acceptors is considered on the basis of the data obtained.

  6. Kinetic Analysis of Parallel-Consecutive First-Order Reactions with a Reversible Step: Concentration-Time Integrals Method

    Science.gov (United States)

    Mucientes, A. E.; de la Pena, M. A.

    2009-01-01

    The concentration-time integrals method has been used to solve kinetic equations of parallel-consecutive first-order reactions with a reversible step. This method involves the determination of the area under the curve for the concentration of a given species against time. Computer techniques are used to integrate experimental curves and the method…

  7. Cintichem modified process - {sup 99}Mo precipitation step: application of statistical analysis tools over the reaction parameters

    Energy Technology Data Exchange (ETDEWEB)

    Teodoro, Rodrigo; Dias, Carla R.B.R.; Osso Junior, Joao A., E-mail: jaosso@ipen.b [Instituto de Pesquisas Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Fernandez Nunez, Eutimio Gustavo [Universidade de Sao Paulo (EP/USP), SP (Brazil). Escola Politecnica. Dept. de Engenharia Quimica

    2011-07-01

    Precipitation of {sup 99}Mo by {alpha}-benzoin oxime ({alpha}-Bz) is a standard precipitation method for molybdenum due the high selectivity of this agent. Nowadays, statistical analysis tools have been employed in analytical systems to prove its efficiency and feasibility. IPEN has a project aiming the production of {sup 99}Mo by the fission of {sup 235}U route. The processing uses as the first step the precipitation of {sup 99}Mo with {alpha}-Bz. This precipitation step involves many key reaction parameters. The aim of this work is based on the development of the already known acidic route to produce {sup 99}Mo as well as the optimization of the reactional parameters applying statistical tools. In order to simulate {sup 99}Mo precipitation, the study was conducted in acidic media using HNO{sub 3}, {alpha}Bz as precipitant agent and NaOH /1%H{sub 2}O{sub 2} as dissolver solution. Then, a Mo carrier, KMnO{sub 4} solutions and {sup 99}Mo tracer were added to the reaction flask. The reactional parameters ({alpha}-Bz/Mo ratio, Mo carrier, reaction time and temperature, and cooling reaction time before filtration) were evaluated under a fractional factorial design of resolution V. The best values of each reactional parameter were determined by a response surface statistical planning. The precipitation and recovery yields of {sup 99}Mo were measured using HPGe detector. Statistical analysis from experimental data suggested that the reactional parameters {alpha}-Bz/Mo ratio, reaction time and temperature have a significant impact on {sup 99}Mo precipitation. Optimization statistical planning showed that higher {alpha}Bz/Mo ratios, room temperature, and lower reaction time lead to higher {sup 99}Mo yields. (author)

  8. Comparison of ground reaction forces during the Basic Step on the Core Board platform at various levels of stability.

    Science.gov (United States)

    Karczewska, Magdalena; Madej, Anna; Sadowska, Aleksandra; Mastalerz, Andrzej; Urbanik, Czesław

    2016-01-01

    The aim of this paper was to examine and compare the changes of ground reaction forces observed during the Basic Step on the Core Board fitness device at various levels of stability. The study involved 10 female students. Participants stepped on and off the Core Board 10 times at 3 levels of stability. After completing a series of steps, the Core Board's stability was modified and the participant repeated the whole series. The measurement platform to examine three components of the reaction force (horizontal in the sagittal and frontal planes, and vertical) was used. The ground reaction force (GRF) observed on the Core Board, in the vertical and horizontal components is higher at all three levels of stability than on the platform without the device. Significant differences in GRF were observed in the horizontal component in the frontal plane (Fz) at all three levels of mobility as well as in impulse, measured on platforms with the device. The results on the Core Board training device present highest horizontal ground reaction forces in frontal plane at the highest level of Core Board mobility and this showing little medio-lateral stability and a more reactive way of movement regulation of the participants. As a consequence of the force patterns found it may be suggested that fitness training concepts should focus more possibly higher strains on the locomotor system most likely caused by changed ground reaction force patterns, an idea that has to be further analyzed with more complex measurement approaches.

  9. Three-stage extraction of gelatines from tendons of abattoir cattle: 1--reaction conditions.

    Science.gov (United States)

    Mokrejs, Pavel; Janacova, Dagmar; Svoboda, Petr

    2012-10-01

    Short and long tendons of abattoir cattle are collagen by-products of the meat industry. They offer no utilisation at present, being a raw material source of over 90 % protein characteristic. This contribution deals with the three-stage extraction of gelatine from short cattle tendons. The principle of treatment consists in processing degreased tendons in the first processing stage in an environment resulting in the swelling of the starting material. In the second stage, the material is treated with a proteolytic enzyme to produce such disruption of the collagen substrate that makes gelatine extraction when boiling possible in the third stage of the process. In order to study the influence of the significant parameters during the extraction process on gelatine yield, experiments were planned using a factor experiment of 2(3) types. The variables under study were the duration of the second processing stage (5-25 h), temperature in the first and second processing stages (10-40 °C) and the addition of a proteolytic enzyme (1-5 %) on the quantity of the extracted gelatine. The results were processed statistically, and statistical significance of the studied factors was thus found. Contour graphs were plotted to easily survey the influence of the observed factors on gelatine yield. The process achieves up to 71 % efficiency, runs under atmospheric pressure and mild reaction conditions, and is conducive to preparing quality gelatines.

  10. Age differences in outcomes among patients in the "Stimulant Abuser Groups to Engage in 12-Step" (STAGE-12) intervention.

    Science.gov (United States)

    Garrett, Sharon B; Doyle, Suzanne R; Peavy, K Michelle; Wells, Elizabeth A; Owens, Mandy D; Shores-Wilson, Kathy; DiCenzo, Jessica; Donovan, Dennis M

    2018-01-01

    Emerging adults (roughly 18-29years) with substance use disorders can benefit from participation in twelve-step mutual-help organizations (TSMHO), however their attendance and participation in such groups is relatively low. Twelve-step facilitation therapies, such as the Stimulant Abuser Groups to Engage in 12-Step (STAGE-12), may increase attendance and involvement, and lead to decreased substance use. Analyses examined whether age moderated the STAGE-12 effects on substance use and TSMHO meeting attendance and participation. We utilized data from a multisite randomized controlled trial, with assessments at baseline, mid-treatment (week 4), end-of-treatment (week 8), and 3- and 6- months post-randomization. Participants were adults with DSM-IV diagnosed stimulant abuse or dependence (N=450) enrolling in 10 intensive outpatient substance use treatment programs across the U.S. A zero-inflated negative binomial random-effects regression model was utilized to examine age-by-treatment interactions on substance use and meeting attendance and involvement. Younger age was associated with larger treatment effects for stimulant use. Specifically, younger age was associated with greater odds of remaining abstinent from stimulants in STAGE-12 versus Treatment-as-Usual; however, among those who were not abstinent during treatment, younger age was related to greater rates of stimulant use at follow-up for those in STAGE-12 compared to TAU. There was no main effect of age on stimulant use. Younger age was also related to somewhat greater active involvement in different types of TSMHO activities among those in STAGE-12 versus TAU. There were no age-by-treatment interactions for other types of substance use or for treatment attendance, however, in contrast to stimulant use; younger age was associated with lower odds of abstinence from non-stimulant drugs at follow-up, regardless of treatment condition. These results suggest that STAGE-12 can be beneficial for some emerging adults

  11. Developmental steps of the human cervical spine: parameters for evaluation of skeletal maturation stages.

    Science.gov (United States)

    dos Santos, Marcos Fabio Henriques; de Lima, Rodrigo Lopes; De-Ary-Pires, Bernardo; Pires-Neto, Mário Ary; de Ary-Pires, Ricardo

    2010-06-01

    The central objective of this investigation was to focus on the development of the cervical spine observed by lateral cephalometric radiological images of children and adolescents (6-16 years old). A sample of 26 individuals (12 girls and 14 boys) was classified according to stages of cervical spine maturation in two subcategories: group I (initiation phase) and group II (acceleration phase). The morphology of the cervical spine was assessed by lateral cephalometric radiographs obtained in accordance with an innovative method for establishing a standardized head posture. A total of 29 linear variables and 5 angular variables were used to clarify the dimensions of the cervical vertebrae. The results suggest that a few measurements can be used as parameters of vertebral maturation both for males and females. The aforementioned measurements include the inferior depth of C2-C4, the inferior depth of C5, the anterior height of C4-C5, and the posterior height of C5. We propose original morphological parameters that may prove remarkably useful in the determination of bone maturational stages of the cervical spine in children and adolescents.

  12. Development of Teaching Material Oxidation-Reduction Reactions through Four Steps Teaching Material Development (4S TMD)

    Science.gov (United States)

    Syamsuri, B. S.; Anwar, S.; Sumarna, O.

    2017-09-01

    This research aims to develop oxidation-reduction reactions (redox) teaching material used the Four Steps Teaching Material Development (4S TMD) method consists of four steps: selection, structuring, characterization and didactical reduction. This paper is the first part of the development of teaching material that includes selection and structuring steps. At the selection step, the development of teaching material begins with the development concept of redox based on curriculum demands, then the development of fundamental concepts sourced from the international textbook, and last is the development of values or skills can be integrated with redox concepts. The results of this selection step are the subject matter of the redox concept and values can be integrated with it. In the structuring step was developed concept map that provide on the relationship between redox concepts; Macro structure that guide systematic on the writing of teaching material; And multiple representations which are the development of teaching material that connection between macroscopic, submicroscopic, and symbolic level representations. The result of the two steps in this first part of the study produced a draft of teaching material. Evaluation of the draft of teaching material is done by an expert lecturer in the field of chemical education to assess the feasibility of teaching material.

  13. Waterhammer Modeling for the Ares I Upper Stage Reaction Control System Cold Flow Development Test Article

    Science.gov (United States)

    Williams, Jonathan H.

    2010-01-01

    The Upper Stage Reaction Control System provides three-axis attitude control for the Ares I launch vehicle during active Upper Stage flight. The system design must accommodate rapid thruster firing to maintain the proper launch trajectory and thus allow for the possibility to pulse multiple thrusters simultaneously. Rapid thruster valve closure creates an increase in static pressure, known as waterhammer, which propagates throughout the propellant system at pressures exceeding nominal design values. A series of development tests conducted in the fall of 2009 at Marshall Space Flight Center were performed using a water-flow test article to better understand fluid performance characteristics of the Upper Stage Reaction Control System. A subset of the tests examined waterhammer along with the subsequent pressure and frequency response in the flight-representative system and provided data to anchor numerical models. This thesis presents a comparison of waterhammer test results with numerical model and analytical results. An overview of the flight system, test article, modeling and analysis are also provided.

  14. Travelling wave and convergence in stage-structured reaction-diffusion competitive models with nonlocal delays

    International Nuclear Information System (INIS)

    Xu Rui; Chaplain, M.A.J.; Davidson, F.A.

    2006-01-01

    In this paper, we first investigate a stage-structured competitive model with time delays, harvesting, and nonlocal spatial effect. By using an iterative technique recently developed by Wu and Zou (Wu J, Zou X. Travelling wave fronts of reaction-diffusion systems with delay. J Dynam Differen Equat 2001;13:651-87), sufficient conditions are established for the existence of travelling front solution connecting the two boundary equilibria in the case when there is no positive equilibrium. The travelling wave front corresponds to an invasion by a stronger species which drives the weaker species to extinction. Secondly, we consider a stage-structured competitive model with time delays and nonlocal spatial effect when the domain is finite. We prove the global stability of each of the nonnegative equilibria and demonstrate that the more complex model studied here admits three possible long term behaviors: coexistence, bistability and dominance as is the case for the standard Lotka-Voltera competitive model

  15. Two-step nuclear reactions: The Surrogate Method, the Trojan Horse Method and their common foundations

    Energy Technology Data Exchange (ETDEWEB)

    Hussein, Mahir S. [DCTA, Instituto Tecnologico de Aeronautica, Sao Jose dos Campos, SP (Brazil); Universidade de Sao Paulo, Instituto de Estudos Avancados, C. P. 72012, Sao Paulo, SP (Brazil); Universidade de Sao Paulo, Instituto de Fisica, C. P. 66318, Sao Paulo, SP (Brazil)

    2017-05-15

    In this Letter I argue that the Surrogate Method, used to extract the fast neutron capture cross section on actinide target nuclei, which has important practical application for the next generation of breeder reactors, and the Trojan Horse Method employed to extract reactions of importance to nuclear astrophysics, have a common foundation, the Inclusive Non-Elastic Breakup (INEB) Theory. Whereas the Surrogate Method relies on the premise that the extracted neutron cross section in a (d, p) reaction is predominantly a compound-nucleus one, the Trojan Horse Method assumes a predominantly direct process for the secondary reaction induced by the surrogate fragment. In general, both methods contain both direct and compound contributions, and I show how these seemingly distinct methods are in fact the same but at different energies and different kinematic regions. The unifying theory is the rather well developed INEB theory. (orig.)

  16. Quantitative expression of regulatory and differentiation-related genes in the key steps of human hematopoiesis: The LeukoStage Database.

    Science.gov (United States)

    Polgárová, K; Vášková, M; Froňková, E; Slámová, L; Kalina, T; Mejstříková, E; Dobiášová, A; Fišer, K; Hrušák, O

    2016-01-01

    Differentiation during hematopoiesis leads to the generation of many cell types with specific functions. At various stages of maturation, the cells may change pathologically, leading to diseases including acute leukemias (ALs). Expression levels of regulatory molecules (such as the IKZF, GATA, HOX, FOX, NOTCH and CEBP families, as well as SPI-1/PU1 and PAX5) and lineage-specific molecules (including CD2, CD14, CD79A, and BLNK) may be compared between pathological and physiological cells. Although the key steps of differentiation are known, the available databases focus mainly on fully differentiated cells as a reference. Precursor cells may be a more appropriate reference point for diseases that evolve at immature stages. Therefore, we developed a quantitative real-time polymerase chain reaction (qPCR) array to investigate 90 genes that are characteristic of the lymphoid or myeloid lineages and/or are thought to be involved in their regulation. Using this array, sorted cells of granulocytic, monocytic, T and B lineages were analyzed. For each of these lineages, 3-5 differentiation stages were selected (17 stages total), and cells were sorted from 3 different donors per stage. The qPCR results were compared to similarly processed AL cells of lymphoblastic (n=18) or myeloid (n=6) origins and biphenotypic AL cells of B cell origin with myeloid involvement (n=5). Molecules characteristic of each lineage were found. In addition, cells of a newly discovered switching lymphoblastic AL (swALL) were sorted at various phases during the supposed transdifferentiation from an immature B cell to a monocytic phenotype. As demonstrated previously, gene expression changed along with the immunophenotype. The qPCR data are publicly available in the LeukoStage Database in which gene expression in malignant and non-malignant cells of different lineages can be explored graphically and differentially expressed genes can be identified. In addition, the LeukoStage Database can aid the

  17. Confidence-increasing elements in user instructions: Seniors' reactions to verification steps and personal stories

    NARCIS (Netherlands)

    Loorbach, N.R.; Karreman, Joyce; Steehouder, M.F.

    2013-01-01

    Purpose: Research shows that confidence-increasing elements in user instructions positively influence senior users' task performance and motivation. We added verification steps and personal stories to user instructions for a cell phone, to find out how seniors (between 60 and 70 years) perceive

  18. Elementary steps and reaction pathways in the aqueous phase alkylation of phenol with ethanol

    Energy Technology Data Exchange (ETDEWEB)

    Eckstein, Sebastian; Hintermeier, Peter H.; Olarte, Mariefel V.; Liu, Yue; Baráth, Eszter; Lercher, Johannes A.

    2017-08-01

    The hydronium ion normalized reaction rate in aqueous phase alkylation of phenol with ethanol on H-MFI zeolites increases with decreasing concentration of acid sites. Higher rates are caused by higher concentrations of phenol in the zeolite pores, as the concentration of hydronium ions generated by zeolite Brønsted acid sites decreases. Considering the different concentrations of reacting species it is shown that the intrinsic rate constant for alkylation is independent of the concentration of hydronium ions in the zeolite pores. Alkylation at the aromatic ring of phenol and of toluene as well as O-alkylation of phenol have the same activation energy, 104 ± 5 kJ/mol. This is energetic barrier to form the ethyl carbenium ion from ethanol associated to the hydronium ion. Thus, in both the reaction pathways the catalyst involves a carbenium ion, which forms a bond to a nucleophilic oxygen (ether formation) or carbon (alkylation).

  19. Retrospective evaluation of adverse transfusion reactions following blood product transfusion from a tertiary care hospital: A preliminary step towards hemovigilance

    Directory of Open Access Journals (Sweden)

    Praveen Kumar

    2013-01-01

    Full Text Available Background: The goal of hemovigilance is to increase the safety and quality of blood transfusion. Identification of the adverse reactions will help in taking appropriate steps to reduce their incidence and make blood transfusion process as safe as possible. Aims : To determine the frequency and type of transfusion reactions (TRs occurring in patients, reported to the blood bank at our institute. Materials and Methods : A retrospective review of all TRs reported to the blood bank at the All India Institute of Medical Sciences, between December 2007 and April 2012 was done. All the TRs were evaluated in the blood bank and classified using standard definitions. Results: During the study period a total of 380,658 bloods and blood components were issued by our blood bank. Out of the total 196 adverse reactions reported under the hemovigilance system, the most common type of reaction observed was allergic 55.1% (n = 108, followed by febrile non-hemolytic transfusion reaction (FNHTR 35.7% (n = 70. Other less frequently observed reactions were Anaphylactoid reactions 5.1% (n = 10, Acute non-immune HTRs 2.6% (n = 5, Circulatory overload 0.5% (n = 1, Transfusion related acute lung injury 0.5% (n = 1, Delayed HTRs 0.5% (n = 1. Not a single case of bacterial contamination was observed. Conclusion: The frequency of TRs in our patients was found to be 0.05% (196 out of 380,658. This can be an underestimation of the true incidence because of under reporting. It should be the responsibility of the blood transfusion consultant to create awareness amongst their clinical counterpart about safe transfusion practices so that proper hemovigilance system can be achieved to provide better patient care.

  20. Biomimicry Promotes the Efficiency of a 10-Step Sequential Enzymatic Reaction on Nanoparticles, Converting Glucose to Lactate.

    Science.gov (United States)

    Mukai, Chinatsu; Gao, Lizeng; Nelson, Jacquelyn L; Lata, James P; Cohen, Roy; Wu, Lauren; Hinchman, Meleana M; Bergkvist, Magnus; Sherwood, Robert W; Zhang, Sheng; Travis, Alexander J

    2017-01-02

    For nanobiotechnology to achieve its potential, complex organic-inorganic systems must grow to utilize the sequential functions of multiple biological components. Critical challenges exist: immobilizing enzymes can block substrate-binding sites or prohibit conformational changes, substrate composition can interfere with activity, and multistep reactions risk diffusion of intermediates. As a result, the most complex tethered reaction reported involves only 3 enzymes. Inspired by the oriented immobilization of glycolytic enzymes on the fibrous sheath of mammalian sperm, here we show a complex reaction of 10 enzymes tethered to nanoparticles. Although individual enzyme efficiency was higher in solution, the efficacy of the 10-step pathway measured by conversion of glucose to lactate was significantly higher when tethered. To our knowledge, this is the most complex organic-inorganic system described, and it shows that tethered, multi-step biological pathways can be reconstituted in hybrid systems to carry out functions such as energy production or delivery of molecular cargo. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. The effect of two-step α transfer reaction in the elastic scattering of 12C+24Mg

    International Nuclear Information System (INIS)

    Lichtenthaler Filho, R.; Lepine-Szily, A.; Villari, A.C.C.; Mittig, W.; Porto, V. de J.G.; Acquadro, C.V.

    1982-06-01

    Angular distribution of the elastic scattering 24 Mg( 12 C, 12 C) 24 Mg and of the 24 Mg( 12 C, 16 O) 20 Ne transfer reaction have been measured at 40 MeV incident energy, respectively in the 20 0 0 and 20 0 0 angular regions. The elastic scattering and transfer reactions were analysed with Frahn's closed formalism as well as with optical model calculations. The influence of the two-step α-transfer channel ( 12 C+ 24 Mg → 16 O+ 20 Ne → 12 C+ 24 Mg) on the elastic scattering was calculated explicitly using the coupled channel extension of the closed formalism. This calculation shows that the coupling between the α-transfer and elastic channel can account for the intermediate angle oscillations observed in the elastic scattering angular distributions. (Author) [pt

  2. Underground structure pattern and multi AO reaction with step feed concept for upgrading an large wastewater treatment plant

    Science.gov (United States)

    Peng, Yi; Zhang, Jie; Li, Dong

    2018-03-01

    A large wastewater treatment plant (WWTP) could not meet the new demand of urban environment and the need of reclaimed water in China, using a US treatment technology. Thus a multi AO reaction process (Anaerobic/oxic/anoxic/oxic/anoxic/oxic) WWTP with underground structure was proposed to carry out the upgrade project. Four main new technologies were applied: (1) multi AO reaction with step feed technology; (2) deodorization; (3) new energy-saving technology such as water resource heat pump and optical fiber lighting system; (4) dependable old WWTP’s water quality support measurement during new WWTP’s construction. After construction, upgrading WWTP had saved two thirds land occupation, increased 80% treatment capacity and improved effluent standard by more than two times. Moreover, it had become a benchmark of an ecological negative capital changing to a positive capital.

  3. The initial step of silicate versus aluminosilicate formation in zeolite synthesis: a reaction mechanism in water with a tetrapropylammonium template

    KAUST Repository

    Trinh, Thuat T.

    2012-01-01

    The initial step for silicate and aluminosilicate condensation is studied in water in the presence of a realistic tetrapropylammonium template under basic conditions. The model corresponds to the synthesis conditions of ZSM5. The free energy profile for the dimer formation ((OH) 3Si-O-Si-(OH) 2O - or [(OH) 3Al-O-Si-(OH) 3] -) is calculated with ab initio molecular dynamics and thermodynamic integration. The Si-O-Si dimer formation occurs in a two-step manner with an overall free energy barrier of 75 kJ mol -1. The first step is associated with the Si-O bond formation and results in an intermediate with a five-coordinated Si, and the second one concerns the removal of the water molecule. The template is displaced away from the Si centres upon dimer formation, and a shell of water molecules is inserted between the silicate and the template. The main effect of the template is to slow down the backward hydrolysis reaction with respect to the condensation one. The Al-O-Si dimer formation first requires the formation of a metastable precursor state by proton transfer from Si(OH) 4 to Al(OH) 4 - mediated by a solvent molecule. It then proceeds through a single step with an overall barrier of 70 kJ mol -1. The model with water molecules explicitly included is then compared to a simple calculation using an implicit continuum model for the solvent. The results underline the importance of an explicit and dynamical treatment of the water solvent, which plays a key role in assisting the reaction. © the Owner Societies 2012.

  4. Sparking fusion: A step toward laser-initiated nuclear fusion reactions

    International Nuclear Information System (INIS)

    Peterson, I.

    1996-01-01

    The fusion furnace at the sun's core burns hydrogen to make helium. Each time two hydrogen nuclei, or protons, merge to create a deuterium nucleus, the process releases energy. A chain of additional energy-producing nuclear reactions then converts deuterium into helium. Because protons, with their like electric charges, naturally repel each other, high temperatures and tremendous pressures are needed to force them together closely enough to initiate and sustain the reactions. These mergers cost energy initially, but the return on that investment proves prodigious. On Earth, such an energy payoff has been achieved only in the uncontrolled fury of a detonated hydrogen bomb. The vision of harnessing and controlling nuclear fusion as a terrestrial energy source has yet to be fulfilled. The proposed National Ignition Facility (NIF) represents an ambitious effort to use powerful lasers to deposit sufficient energy in a small capsule of nuclear fuel to trigger fusion. The main justification for the project is to ensure that a core group of physicists and engineers maintains its expertise in the physics of nuclear weapons. This article presents both the scientific and political sides of the NIF facility

  5. Production of ethyl ester from crude palm oil by two-step reaction using continuous microwave system

    Directory of Open Access Journals (Sweden)

    Sukritthira Ratanawilai

    2011-02-01

    Full Text Available The esterification of free fatty acids (FFA in vegetable oils with alcohol using an acid catalyst is a promising methodto convert FFA into valuable ester and obtain a FFA-free oil that can be further transesterified using alkali bases. In thiswork, the direct esterification reaction of FFA in crude palm oil to ethyl ester by continuous microwave was studied and theeffects of the main variables involved in the process, amount of catalyst, reaction time and the molar ratio oil/ alcohol, wereanalyzed. The optimum condition for the continuous esterification process was carried out with a molar ratio of oil to ethanol1:6, using 1.25%wt of H2SO4/oil as a catalyst, microwave power of 78 W and a reaction time 90 min. This esterification processshows that the amount of FFA was reduced from 7.5%wt to values around 1.4 %wt. Similar results were obtained followingconventional heating at 70°C, but only after a reaction time of 240 min. The esterified crude palm oil is suitable to perform thetransesterification process. Transesterification of the esterified palm oil has been accomplished with a molar ratio of oil toethanol of 1:8.5, 2.5%wt of KOH as a catalyst, a microwave power of 78 W, and a reaction time of 7 min. In addition, theproblem of glycerin separation was solved by mixing 10%wt of pure glycerin into the ethyl ester to induce the glycerin fromthe reaction to separated. This two-step esterification and transesterification process provided a yield of 78%wt with anester content of 97.4%wt. The final ethyl ester product met with the specifications stipulated by ASTM D6751-02.

  6. Hydrogenation of O and OH on Pt(111): a comparison between the reaction rates of the first and the second hydrogen addition steps.

    Science.gov (United States)

    Näslund, L-Å

    2014-03-14

    The formation of water through hydrogenation of oxygen on platinum occurs at a surprisingly low reaction rate. The reaction rate limited process for this catalytic reaction is, however, yet to be settled. In the present work, the reaction rates of the first and the second hydrogen addition steps are compared when hydrogen is obtained through intense synchrotron radiation that induces proton production in a water overlayer on top of the adsorbed oxygen species. A substantial amount of the produced hydrogen diffuses to the platinum surface and promotes water formation at the two starting conditions O/Pt(111) and (H2O+OH)/Pt(111). The comparison shows no significant difference in the reaction rate between the first and the second hydrogen addition steps, which indicates that the rate determining process of the water formation from oxygen on Pt(111) is neither the first nor the second H addition step or, alternatively, that both H addition steps exert rate control.

  7. A simple test of choice stepping reaction time for assessing fall risk in people with multiple sclerosis.

    Science.gov (United States)

    Tijsma, Mylou; Vister, Eva; Hoang, Phu; Lord, Stephen R

    2017-03-01

    Purpose To determine (a) the discriminant validity for established fall risk factors and (b) the predictive validity for falls of a simple test of choice stepping reaction time (CSRT) in people with multiple sclerosis (MS). Method People with MS (n = 210, 21-74y) performed the CSRT, sensorimotor, balance and neuropsychological tests in a single session. They were then followed up for falls using monthly fall diaries for 6 months. Results The CSRT test had excellent discriminant validity with respect to established fall risk factors. Frequent fallers (≥3 falls) performed significantly worse in the CSRT test than non-frequent fallers (0-2 falls). With the odds of suffering frequent falls increasing 69% with each SD increase in CSRT (OR = 1.69, 95% CI: 1.27-2.26, p = falls in people with MS. This test may prove useful in documenting longitudinal changes in fall risk in relation to MS disease progression and effects of interventions. Implications for rehabilitation Good choice stepping reaction time (CSRT) is required for maintaining balance. A simple low-tech CSRT test has excellent discriminative and predictive validity in relation to falls in people with MS. This test may prove useful documenting longitudinal changes in fall risk in relation to MS disease progression and effects of interventions.

  8. Double-step processes in the 12C(p,d)11C reaction at 45 MeV

    International Nuclear Information System (INIS)

    Couvert, Pierre.

    1974-01-01

    12 C(p,d) 11 C pick-up reaction was performed with a 45 MeV proton beam. A 130keV energy resolution was obtained and angular distributions of nine of the ten first levels of 11 C have been extracted within a large angular range. Assuming only neutron direct transfert, the strong relative excitation of high spin levels cannot be reproduced by a DWBA analysis. The double-step process assumption seems to be verified by a systematical analysis of the (p,d) reaction mechanisms. This analysis is done in the coupled-channel formalism for the five first negative parity states of 11 C. The 3/2 - ground state is essentially populated by the direct transfer of a Psub(3/2) neutron. The contribution of a double-step process, via the 2 + inelastic excitation of 12 C, is important for the four other states. A mechanism which assumes a deuteron inelastic scattering on the 11 C final nucleus after the neutron transfer cannot be neglected and improves the fits when it is taken into account [fr

  9. Compositional change of some first wall materials by considering multiple step nuclear reaction

    Energy Technology Data Exchange (ETDEWEB)

    Noda, Tetsuji; Utsumi, Misako; Fujita, Mitsutane [National Research Inst. for Metals, Tsukuba, Ibaraki (Japan)

    1997-03-01

    The conceptual system for nuclear material design is considered and some trials on WWW server with functions of the easily accessible simulation of nuclear reactions are introduced. Moreover, as an example of the simulation on the system using nuclear data, transmutation calculation was made for candidate first wall materials such as 9Cr-2W steel, V-5Cr-5Ti and SiC in SUS316/Li{sub 2}O/H{sub 2}O(SUS), 9Cr-2WLi{sub 2}O/H{sub 2}O(RAF), V alloy/Li/Be(V), and SiC/Li{sub 2}ZrO{sub 3}/He(SiC) blanket/shield systems based on ITER design model. Neutron spectrum varies with different blanket/shield compositions. The flux of low energy neutrons decreases in order of V-SiC-RAF-SUS blanket/shield systems. Fair amounts of W depletion in 9Cr-2W steel and the increase of Cr content in V-5Cr-5Ti were predicted in SUS or RAF systems. Concentration change in W and Cr is estimated to be suppressed if Li coolant is used in place of water. Helium and hydrogen production are not strongly affected by the different blanket/shield compositions. (author)

  10. Post-sulfonation of cellulose nanofibrils with a one-step reaction to improve dispersibility.

    Science.gov (United States)

    Luo, Jeffrey; Semenikhin, Nikolay; Chang, Huibin; Moon, Robert J; Kumar, Satish

    2018-02-01

    Cellulose nanofibrils (CNF) were sulfonated and the dispersion quality was compared to unfunctionalized and 2,2,6,6-tetramethylpiperdine-1-oxyl radical (TEMPO) post-oxidation treatment of existing CNF (mechanically fibrillated pulp). A post-sulfonation treatment on existing CNF in chlorosulfonic acid and dimethylformamide (DMF) resulted in sulfonated CNF that retained a fibril-like morphology. There was a small decrease in the cellulose crystallinity index for the sulfonated CNF, but this was much lower than the reported regioselective oxidative bisulfite pretreatment method used to make sulfonated CNF. The current approach was extremely quick, and 5min of reaction time was sufficient to result in significant improvements in dispersibility compared to unfunctionalized CNF. The sulfonated CNF and TEMPO oxidized CNF had better dispersibility compared to the unfunctionalized CNF when dispersed in DMF and water, and in many cases the sulfonated CNF had better dispersibility than the TEMPO CNF. It was found that when CNF was dispersed in DMF the TEMPO CNF formed carboxyl dimethylammonium groups, while the sulfonated CNF formed formate groups. Copyright © 2017 Elsevier Ltd. All rights reserved.

  11. Aldimine Formation Reaction, the First Step of the Maillard Early-phase Reaction, Might be Enhanced in Variant Hemoglobin, Hb Himeji.

    Science.gov (United States)

    Koga, Masafumi; Inada, Shinya; Shimizu, Sayoko; Hatazaki, Masahiro; Umayahara, Yutaka; Nishihara, Eijun

    2015-01-01

    Hb Himeji (β140Ala→Asp) is known as a variant hemoglobin in which glycation is enhanced and HbA1c measured by immunoassay shows a high value. The phenomenon of enhanced glycation in Hb Himeji is based on the fact that the glycation product of variant hemoglobin (HbX1c) shows a higher value than HbA1c. In this study, we investigated whether aldimine formation reaction, the first step of the Maillard early-phase reaction, is enhanced in Hb Himeji in vitro. Three non-diabetic subjects with Hb Himeji and four non-diabetic subjects without variant hemoglobin were enrolled. In order to examine aldimine formation reaction, whole blood cells were incubated with 500 mg/dl of glucose at 37°C for 1 hour and were analyzed by high-performance liquid chromatography. Both HbA1c and HbX1c were not increased in this condition. After incubation with glucose, labile HbA1c (LA1c) fraction increased in the controls (1.1±0.3%). In subjects with Hb Himeji increases in the labile HbX1c (LX1c) fraction as well as the LA1c fraction were observed, and the degree of increase in the LX1c fraction was significantly higher than that of the LA1c fraction (1.8±0.1% vs. 0.5±0.2%, Preaction might be enhanced in Hb Himeji in vitro. The 140th amino acid in β chain of hemoglobin is suggested to be involved in aldimine formation reaction. © 2015 by the Association of Clinical Scientists, Inc.

  12. Optimizing multi-step B-side charge separation in photosynthetic reaction centers from Rhodobacter capsulatus

    Energy Technology Data Exchange (ETDEWEB)

    Faries, Kaitlyn M. [Washington Univ., St. Louis, MO (United States); Kressel, Lucas L. [Argonne National Lab. (ANL), Argonne, IL (United States); Dylla, Nicholas P. [Argonne National Lab. (ANL), Argonne, IL (United States); Wander, Marc J. [Argonne National Lab. (ANL), Argonne, IL (United States); Hanson, Deborah K. [Argonne National Lab. (ANL), Argonne, IL (United States); Holten, Dewey [Washington Univ., St. Louis, MO (United States); Laible, Philip D. [Argonne National Lab. (ANL), Argonne, IL (United States); Kirmaier, Christine [Washington Univ., St. Louis, MO (United States)

    2016-02-01

    Using high-throughput methods for mutagenesis, protein isolation and charge-separation functionality, we have assayed 40 Rhodobacter capsulatus reaction center (RC) mutants for their P+ QB- yield (P is a dimer of bacteriochlorophylls and Q is a ubiquinone) as produced using the normally inactive B-side cofactors BB and HB (where B is a bacteriochlorophyll and H is a bacteriopheophytin). Two sets of mutants explore all possible residues at M131 (M polypeptide, native residue Val near HB) in tandem with either a fixed His or a fixed Asn at L181 (L polypeptide, native residue Phe near BB). A third set of mutants explores all possible residues at L181 with a fixed Glu at M131 that can form a hydrogen bond to HB. For each set of mutants, the results of a rapid millisecond screening assay that probes the yield of P+ QB- are compared among that set and to the other mutants reported here or previously. For a subset of eight mutants, the rate constants and yields of the individual B-side electron transfer processes are determined via transient absorption measurements spanning 100 fs to 50 μs. The resulting ranking of mutants for their yield of P+ QB- from ultrafast experiments is in good agreement with that obtained from the millisecond screening assay, further validating the efficient, high-throughput screen for B-side transmembrane charge separation. Results from mutants that individually show progress toward optimization of P+ HB- → P+ QB- electron transfer or initial P* → P+ HB- conversion highlight unmet challenges of optimizing both processes simultaneously.

  13. Early stages of interface reactions between AlN and Ti thin films

    CERN Document Server

    Pinkas, M; Froumin, N; Pelleg, J; Dariel, M P

    2002-01-01

    The early stages of interface reactions between AlN and Ti thin films were investigated using x-ray diffractions, Auger electron spectroscopy, cross section transmission electron microscopy (XTEM), and high resolution XTEM. The AlN/Ti bilayers were deposited on a molybdenum substrate using reactive and nonreactive magnetron sputtering techniques. After deposition, the bilayers were heat treated for 1-10 h at 600 deg. C in a nitrogen atmosphere. Decomposition of the AlN layer took place at the AlN/Ti interface and its products, Al and N, reacted with Ti to produce a AlN/Al sub 3 Ti/Ti sub 2 N/Ti sub 3 Al/alpha-(Ti, Al)ss phase sequence. This phase sequence is not consistent with the Ti-Al-N phase diagram and is believed to be the outcome of the particular conditions that prevail in the thin film and correspond to a particular set of kinetic parameters. A model that explains the development of the phase sequence and predicts its evolution after prolonged heat treatments is put forward. The applicability of such...

  14. Compact Ag@Fe3O4 Core-shell Nanoparticles by Means of Single-step Thermal Decomposition Reaction

    Science.gov (United States)

    Brollo, Maria Eugênia F.; López-Ruiz, Román; Muraca, Diego; Figueroa, Santiago J. A.; Pirota, Kleber R.; Knobel, Marcelo

    2014-10-01

    A temperature pause introduced in a simple single-step thermal decomposition of iron, with the presence of silver seeds formed in the same reaction mixture, gives rise to novel compact heterostructures: brick-like Ag@Fe3O4 core-shell nanoparticles. This novel method is relatively easy to implement, and could contribute to overcome the challenge of obtaining a multifunctional heteroparticle in which a noble metal is surrounded by magnetite. Structural analyses of the samples show 4 nm silver nanoparticles wrapped within compact cubic external structures of Fe oxide, with curious rectangular shape. The magnetic properties indicate a near superparamagnetic like behavior with a weak hysteresis at room temperature. The value of the anisotropy involved makes these particles candidates to potential applications in nanomedicine.

  15. Detection of Listeria monocytogenes in ready-to-eat food by Step One real-time polymerase chain reaction.

    Science.gov (United States)

    Pochop, Jaroslav; Kačániová, Miroslava; Hleba, Lukáš; Lopasovský, L'ubomír; Bobková, Alica; Zeleňáková, Lucia; Stričík, Michal

    2012-01-01

    The aim of this study was to follow contamination of ready-to-eat food with Listeria monocytogenes by using the Step One real time polymerase chain reaction (PCR). We used the PrepSEQ Rapid Spin Sample Preparation Kit for isolation of DNA and MicroSEQ® Listeria monocytogenes Detection Kit for the real-time PCR performance. In 30 samples of ready-to-eat milk and meat products without incubation we detected strains of Listeria monocytogenes in five samples (swabs). Internal positive control (IPC) was positive in all samples. Our results indicated that the real-time PCR assay developed in this study could sensitively detect Listeria monocytogenes in ready-to-eat food without incubation.

  16. Study of initial stage in coal liquefaction. Increase in oil yield with suppression of retrogressive reaction during initial stage; Ekika hanno no shoki katei ni kansuru kenkyu. 1.

    Energy Technology Data Exchange (ETDEWEB)

    Uesugi, K.; Kanaji, M.; Kaneko, T.; Shimasaki, K. [Nippon Brown Coal Liquefaction Co. Ltd., Tokyo (Japan)

    1996-10-28

    For the coal liquefaction, improvement of liquefaction conditions and increase of liquefied oil yield are expected by suppressing the recombination through rapid stabilization of pyrolytic radicals which are formed at the initial stage of liquefaction. Two-stage liquefaction combining prethermal treatment and liquefaction was performed under various conditions, to investigate the effects of reaction conditions on the yields and properties of products as well as to increase liquefied oil yield. Consequently, it was found that the catalyst contributes greatly to the hydrogen transfer to coal at the prethermal treatment. High yield of n-hexane soluble fraction with products having low condensation degree could be obtained by combining the prethermal treatment in the presence of hydrogen and catalyst with the concentration of slurry after the treatment. This was considered to be caused by the synergetic effect between the improvement of liquefaction by suppressing polymerization/condensation at the initial stage of reaction through the prethermal treatment and the effective hydrogen transfer accompanied with the improvement of contact efficiency of coal/catalyst by the concentration of slurry at the stage of liquefaction. 4 refs., 8 figs.

  17. Validity and reliability of a simple 'low-tech' test for measuring choice stepping reaction time in older people.

    Science.gov (United States)

    Delbaere, K; Gschwind, Y J; Sherrington, C; Barraclough, E; Garrués-Irisarri, M A; Lord, S R

    2016-11-01

    To establish the psychometric properties of a simple 'low-tech' choice stepping reaction time test (CSRT-M) by investigating its validity and test-retest reliability. Cross-sectional. Community. A total of 169 older people from the control arm of a clinical trial and a convenience sample of 30 older people. Demographic, physical, cognitive and prospective falls data were collected in addition to CSRT-M. The CSRT-M time was taken as the total time to complete 20 steps onto four targets printed on a portable rubber mat. Assessment of the original electronic version (CSRT-E) and re-administration of the CSRT-M the next day was done in 30 participants. Multivariate regression analysis showed that the CSRT-M time was best explained by leaning balance control, quadriceps strength and cognitive functioning (R 2  = 0.44). Performance on the CSRT-M was worse in older participants and participants with a presence of fall risk factors, supporting good discriminant validity. The odds of suffering multiple future falls increased by 74% (odds ratio (OR) = 1.74, 95% CI (confidence interval) = 1.14-2.65, p = 0.010) for each standard deviation increase in CSRT-M, supporting good predictive validity. Criterion validity was confirmed by a strong bivariate correlation between CSRT-M and CSRT-E (0.81, p Test-retest reliability for the CSRT-M was good (intraclass correlation coefficient = 0.74, 95% CI = 0.45-0.88, p test of unplanned volitional stepping (CSRT-M) has excellent predictive validity for future falls, good inter-day test-retest reliability and excellent criterion validity with respect to the well-validated CSRT-E. The CSRT-M, therefore, may be a useful fall risk screening tool for older people.

  18. One step synthesis of chlorine-free Pt/Nitrogen-doped graphene composite for oxygen reduction reaction

    KAUST Repository

    Varga, Tamás

    2018-03-14

    Chlorine-free Platinum/nitrogen-doped graphene oxygen reduction reaction catalysts were synthesized by a one step method of annealing a mixture of platinum acetylacetonate and graphene oxide under ammonia atmosphere. Nanoparticles with close to the ideal particle size for oxygen reduction reaction (ORR) were formed, i.e., with diameter of 3–4 nm (500 and 600 °C) and 6 nm (700 °C). X-ray photoelectron spectroscopy confirmed the successful introduction of both pyridinic and pyrrolic type nitrogen moieties into the graphene layers, which indicates a strong interaction between the nanoparticles and the graphene layers. The electrocatalytic activity of glassy carbon electrodes (GCE) modified with the synthesized Pt/NG samples for oxygen reduction was compared to that of a platinum/carbon black catalyst modified electrode in acidic and alkaline media. Based on the measured limiting current densities and calculated electron transfer number, the highest activity was measured in acidic and alkaline media on the samples annealed at 600 and 700 °C, respectively.

  19. Kinetics of elementary steps in the reactions of atomic bromine with isoprene and 1,3-butadiene under atmospheric conditions.

    Science.gov (United States)

    Laine, Patrick L; Sohn, Yoon S; Nicovich, J Michael; McKee, Michael L; Wine, Paul H

    2012-06-21

    Laser flash photolysis of CF(2)Br(2) has been coupled with time-resolved detection of atomic bromine by resonance fluorescence spectroscopy to investigate the gas-phase kinetics of early elementary steps in the Br-initiated oxidations of isoprene (2-methyl-1,3-butadiene, Iso) and 1,3-butadiene (Bu) under atmospheric conditions. At T ≥ 526 K, measured rate coefficients for Br + isoprene are independent of pressure, suggesting that hydrogen transfer (1a) is the dominant reaction pathway. The following Arrhenius expression adequately describes all kinetic data at 526 K ≤ T ≤ 673 K: k(1a)(T) = (1.22 ± 0.57) × 10(-11) exp[(-2100 ± 280)/T] cm(3) molecule(-1) s(-1) (uncertainties are 2σ and represent precision of the Arrhenius parameters). At 271 K ≤ T ≤ 357 K, kinetic evidence for the reversible addition reactions Br + Iso ↔ Br-Iso (k(1b), k(-1b)) and Br + Bu ↔ Br-Bu (k(3b), k(-3b)) is observed. Analysis of the approach to equilibrium data allows the temperature- and pressure-dependent rate coefficients k(1b), k(-1b), k(3b), and k(-3b) to be evaluated. At atmospheric pressure, addition of Br to each conjugated diene occurs with a near-gas-kinetic rate coefficient. Equilibrium constants for the addition/dissociation reactions are obtained from k(1b)/k(-1b) and k(3b)/k(-3b), respectively. Combining the experimental equilibrium data with electronic structure calculations allows both second- and third-law analyses of thermochemistry to be carried out. The following thermochemical parameters for the addition reactions 1b and 3b at 0 and 298 K are obtained (units are kJ mol(-1) for Δ(r)H and J mol(-1) K(-1) for Δ(r)S; uncertainties are accuracy estimates at the 95% confidence level): Δ(r)H(0)(1b) = -66.6 ± 7.1, Δ(r)H(298)(1b) = -67.5 ± 6.6, and Δ(r)S(298)(3b) = -93 ± 16; Δ(r)H(0)(3b) = -62.4 ± 9.0, Δ(r)H(298)(3b) = -64.5 ± 8.5, and Δ(r)S(298)(3b) = -94 ± 20. Examination of the effect of added O(2) on Br kinetics under conditions where reversible

  20. Impairment of reaction time among children awakened during stage 4 sleep.

    Science.gov (United States)

    Splaingard, Mark; Hayes, John; Smith, Gary A

    2007-01-01

    Sleep inertia refers to impairments in cognitive/motor performance and the tendency to return to sleep after awakening. As part of a project studying the effect of different types of 100 decibel (dB) sounds on awakening children during stage 4 sleep (S4S), we hypothesized that children with the greatest impairment in auditory arousal during S4S, manifested by the inability to either awaken to 100 dB sounds or successfully perform a self-rescue sequence (SRS), would have greater impairments in reaction time (RT) upon awakening than children who awoke and successfully accomplish a SRS. Observational study. Pediatric hospital-based sleep center. Healthy children aged 6-12 years. N/A. RT was measured in 44 children approximately 90 minutes before bedtime and again after awakening by either 100 dB alarms or manually during the first and second cycles of S4S. Overall, mean and median RT slowed significantly by 37% and 22%, respectively, from baseline. Slowing of RT was most evident in the youngest children (aged 6-7 years) and after awakening from the second S4S cycle. Impairments in RT were not significantly different among children who successfully awakened to the alarm and performed a SRS compared with children who did not. The degree of slowing of RT was not significantly different among children who awakened and performed an SRS compared with children who did not. The greatest slowing of RT was seen among younger children and after awakening from the second S4S cycle.

  1. The general theory of multistage geminate reactions of isolated pairs of reactants. III. Two-stage reversible dissociation in geminate reaction A + A ↔ C ↔ B + B.

    Science.gov (United States)

    Kipriyanov, Alexey A; Kipriyanov, Alexander A; Doktorov, Alexander B

    2016-04-14

    Specific two-stage reversible reaction A + A ↔ C ↔ B + B of the decay of species C reactants by two independent transition channels is considered on the basis of the general theory of multistage reactions of isolated pairs of reactants. It is assumed that at the initial instant of time, the reacting system contains only reactants C. The employed general approach has made it possible to consider, in the general case, the inhomogeneous initial distribution of reactants, and avoid application of model concepts of a reaction system structure (i.e., of the structure of reactants and their molecular mobility). Slowing of multistage reaction kinetics as compared to the kinetics of elementary stages is established and physically interpreted. To test approximations (point approximation) used to develop a universal kinetic law, a widely employed specific model of spherical particles with isotropic reactivity diffusing in solution is applied. With this particular model as an example, ultimate kinetics of chemical conversion of reactants is investigated. The question concerning the depths of chemical transformation at which long-term asymptotes are reached is studied.

  2. Nuclear reactions in stellar helium burning and later hydrostatic burning stages

    International Nuclear Information System (INIS)

    Buchmann, L.R.; Barnes, C.A.

    2006-01-01

    We review in some detail, the so-called triple-α process and the reaction 12 C(α,γ) 16 O that follow core hydrogen burning and produce most of the universal abundances of 12 C and 16 O, including considerable new and previously unpublished work. We also review briefly, for reasons of length, some of the principal nuclear reactions involved in carbon burning, neon burning, oxygen burning, the reactions generally grouped under the title silicon burning, and the helium-induced reactions that produce neutrons to build the s-process nuclei

  3. Analysis of Chemical Reaction Kinetics Behavior of Nitrogen Oxide During Air-staged Combustion in Pulverized Boiler

    Directory of Open Access Journals (Sweden)

    Jun-Xia Zhang

    2016-03-01

    Full Text Available Because the air-staged combustion technology is one of the key technologies with low investment running costs and high emission reduction efficiency for the pulverized boiler, it is important to reveal the chemical reaction kinetics mechanism for developing various technologies of nitrogen oxide reduction emissions. At the present work, a three-dimensional mesh model of the large-scale four corner tangentially fired boiler furnace is established with the GAMBIT pre-processing of the FLUENT software. The partial turbulent premixed and diffusion flame was simulated for the air-staged combustion processing. Parameters distributions for the air-staged and no the air-staged were obtained, including in-furnace flow field, temperature field and nitrogen oxide concentration field. The results show that the air-staged has more regular velocity field, higher velocity of flue gas, higher turbulence intensity and more uniform temperature of flue gas. In addition, a lower negative pressure zone and lower O2 concentration zone is formed in the main combustion zone, which is conducive to the NO of fuel type reduced to N2, enhanced the effect of NOx reduction. Copyright © 2016 BCREC GROUP. All rights reserved Received: 5th November 2015; Revised: 14th January 2016; Accepted: 16th January 2016  How to Cite: Zhang, J.X., Zhang, J.F. (2016. Analysis of Chemical Reaction Kinetics Behavior of Nitrogen Oxide During Air-staged Combustion in Pulverized Boiler. Bulletin of Chemical Reaction Engineering & Catalysis, 11 (1: 100-108. (doi:10.9767/bcrec.11.1.431.100-108 Permalink/DOI: http://dx.doi.org/10.9767/bcrec.11.1.431.100-108

  4. Examining the rudimentary steps of the oxygen reduction reaction on single-atomic Pt using Ti-based non-oxide supports

    DEFF Research Database (Denmark)

    Tak, Young Joo; Yang, Sungeun; Lee, Hyunjoo

    2018-01-01

    In the attempt to reduce the high-cost and improve the overall durability of Pt-based electrocatalysts for the oxygen reduction reaction (ORR), density-functional theory (DFT) calculations have been performed to study the energetics of the elementary steps that occur during ORR on TiN(100)- and T...... of the single-atom Pt catalyst, and directly influences the rudimentary ORR steps on these single-atom platinized supports....

  5. Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction

    OpenAIRE

    Saed, Mohand O.; Torbati, Amir H.; Nair, Devatha P.; Yakacki, Christopher M.

    2016-01-01

    This study presents a novel two-stage thiol-acrylate Michael addition-photopolymerization (TAMAP) reaction to prepare main-chain liquid-crystalline elastomers (LCEs) with facile control over network structure and programming of an aligned monodomain. Tailored LCE networks were synthesized using routine mixing of commercially available starting materials and pouring monomer solutions into molds to cure. An initial polydomain LCE network is formed via a self-limiting thiol-acrylate Michael-addi...

  6. A divergent approach to the synthesis of simplexides and congeners via a late-stage olefin cross-metathesis reaction.

    Science.gov (United States)

    Li, Jiakun; Li, Wei; Yu, Biao

    2013-08-14

    Simplexides constitute a unique group of immunosuppressive glycolipids that demonstrate antiproliferative activities against activated T-cell lymphocytes via a unique non-cytotoxic inhibition. To investigate the structure-activity relationship of the varied long-chain secondary alcohols on simplexides, we developed an efficient and divergent route to the synthesis of simplexides and congeners, taking advantage of a late-stage olefin cross-metathesis reaction.

  7. On the time behaviour of the concentration of pyrazinium radical cations in the early stage of the Maillard reaction

    Science.gov (United States)

    Stoesser, Reinhard; Klein, Jeannette; Peschke, Simone; Zehl, Andrea; Cämmerer, Bettina; Kroh, Lothar W.

    2007-08-01

    During the early stage of the Maillard reaction pyrazinium radical cations were detected by ESR within the reaction system D-glucose/glycine. The spectra were characterized by completely resolved hyperfine structure. The partial pressure of oxygen and the radical concentrations were measured directly in the reaction mixture by ESR using solutions of the spin probe TEMPOL and of DPPH, respectively. There are quantitative and qualitative relations of the actual concentration of the radical ions to the partial pressure of oxygen, the temperature-time regime and the mechanical mixing of the reaction system. These macroscopic parameters significantly affect both the induction period and the velocity of the time-dependent formation of free radicals. From in situ variations of p(O 2) and p(Ar) including the connected mixing effects caused by the passing the gases through the reaction mixture, steric and chemical effects of the stabilization of the radical ions were established. The determination of suitable and relevant conditions for stabilization and subsequent radical reactions contributes to the elucidation of the macroscopically known antioxidant activity of Maillard products.

  8. One-step Conversion of Levulinic Acid to Succinic Acid Using I2/t-BuOK System: The Iodoform Reaction Revisited.

    Science.gov (United States)

    Kawasumi, Ryosuke; Narita, Shodai; Miyamoto, Kazunori; Tominaga, Ken-Ichi; Takita, Ryo; Uchiyama, Masanobu

    2017-12-21

    The iodoform reaction has long been used as a qualitative test for acetyl and/or ethanol units in organic molecules. However, its synthetic applications are quite limited. Here, we describe a tuned iodoform reaction for oxidative demethylation reaction with I 2 and t-BuOK in t-BuOH, in which in situ-generated t-BuOI serves as the chemoselective iodinating agent. This system enables one-step conversion of levulinic acid to succinic acid, a major four-carbon chemical feedstock. This oxidative demethylation is also applicable to other compounds containing an acetyl group/ethanol unit, affording the corresponding carboxylic acids in a selective manner.

  9. Altered Dynamic Postural Control during Step Turning in Persons with Early-Stage Parkinson’s Disease

    Directory of Open Access Journals (Sweden)

    Jooeun Song

    2012-01-01

    Full Text Available Persons with early-stage Parkinson’s disease (EPD do not typically experience marked functional deficits but may have difficulty with turning tasks. Studies evaluating turning have focused on individuals in advanced stages of the disease. The purpose of this study was to compare postural control strategies adopted during turning in persons with EPD to those used by healthy control (HC subjects. Fifteen persons with EPD, diagnosed within 3 years, and 10 HC participated. Participants walked 4 meters and then turned 90°. Dynamic postural control was quantified as the distance between the center of pressure (COP and the extrapolated center of mass (eCOM. Individuals with EPD demonstrated significantly shorter COP-eCOM distances compared to HC. These findings suggest that dynamic postural control during turning is altered even in the early stages of PD.

  10. The effect of aging on the backward stepping reaction as estimated from the velocity of center of foot pressure and muscular strength.

    Science.gov (United States)

    Takeuchi, Yahiko; Tanaka, Yasuyuki; Shimomura, Yoshihiro; Iwanaga, Koichi; Katsuura, Tetsuo

    2007-03-01

    By estimating the deflection velocity from the center of foot pressure (COP), this study aims to prove that the characteristics of the backward stepping reaction in the elderly are related to the strength of the antigravity muscles. The participants in this study were 10 elderly (average age 75.6+/-7.6 years) and 13 young (average age 22.0+/-2.6 years) subjects. Using force plate analysis, we measured the shift in the deflection velocity (V-RMS) and the maximum deflection velocity (V-MAX) from the beginning of the COP movement to the onset of the stepping reaction. Furthermore, we measured the strength of the antigravity muscles using a hand-held dynamometer. We correlated the V-RMS, V-MAX, and the rate of change of the deflection velocity (MAX/RMS) with muscular strength. When compared with the young subjects, the elderly showed significantly lower values of V-RMS (pelderly showed significantly lower values of muscular strength for all muscles studied (pmuscular strength by carrying out a regression analysis (V-RMS: gluteus maximus (r=0.50, pmuscular strength of the subjects. Therefore, further investigations should be undertaken in order to understand the effects of aging on the stepping reaction. In other words, the change-in-support strategy, including the preparatory phase of the stepping reaction, and its relationship with muscular strength should be further investigated.

  11. A case report of successful intraoperative photo- dynamic therapy as the step of combined modality treatment in patient with stage IIIb breast cancer

    Directory of Open Access Journals (Sweden)

    E. К. Saribekyan

    2013-01-01

    Full Text Available The case of successful combined modality treatment in patient with stage IIIB T4bN1M0 breast cancer is reported. The first step included 2 courses of neoadjuvant polychemotherapy in CAF regimen with decrease of tumor size. The second step was irradiation (total dose of 45 Gy of breast and areas of regional metastasis. The third step was radical mastectomy by Madden with polypositional intraoperative photodynamic therapy with photosens (the output laser power 1500 mW, light dose 30 J/cm2, total time of irradiation – 25.6 min. The histological study of surgical specimen showed infiltrative ductal carcinoma with metastases in 3 nodes without fat invasion. In the post-operative period the patient had 3 courses of adjuvant chemotherapy in CAF regimen. Currently the duration of recurrence-free survival after treatment is 4 years. 

  12. A novel one-pot de-blocking and conjugation reaction step leads to process intensification in the manufacture of PEGylated insulin IN-105.

    Science.gov (United States)

    Hazra, Partha; Chatterjee, Amarnath; Shabandri, Qais; Adhikary, Laxmi; Dave, Nitesh; Buddha, Madhavan

    2012-10-01

    Bio-catalytic in vitro multistep reactions can be combined in a single step in one pot by optimizing multistep reactions under identical reaction condition. Using this analogy, the process of making PEGylated insulin, IN-105, was simplified. Instead of taking the purified active insulin bulk powder as the starting material for the conjugation step, an insulin process intermediate, partially purified insulin ester, was taken as starting material. Process intensification (PI) was established by performing a novel de-blocking (de-esterification) of the partially purified insulin ester and conjugation at B-29 Lys residue of B chain with a short-chain methoxy polyethylene glycol (mPEG) in a single-pot reactor. The chromatographic profile at the end of the reaction was found similar irrespective of whether both the reactions were performed sequentially or simultaneously. The conjugated product of interest, IN-105 (conjugation at LysB(29)), was purified from the heterogeneous mixture of conjugated products. The new manufacturing process was deduced to be more simplified and economical in making the insulin conjugates as several downstream purification steps could be circumvented. The physicochemical characteristics of IN-105 manufactured through this economic process was found to be indifferent from the product formed through the traditional process where the conjugation starting material was purified from bulk insulin.

  13. Treatment influencing down-staging in EORTC Melanoma Group sentinel node histological protocol compared with complete step-sectioning

    DEFF Research Database (Denmark)

    Riber-Hansen, Rikke; Hastrup, Nina; Clemmensen, Ole

    2012-01-01

    Metastasis size in melanoma sentinel lymph nodes (SLNs) is an emerging prognostic factor. Two European melanoma treatment trials include SLN metastasis diameters as inclusion criteria. Whilst diameter estimates are sensitive to the number of sections examined, the level of this bias is largely...... unknown. We performed a prospective multicentre study to compare the European Organisation for Research and Treatment of Cancer (EORTC) recommended protocol with a protocol of complete step-sectioning....

  14. Multi-step processes in the (d, t) and (d, 3He) reactions on 116Sn and 208Pb targets at Ed = 200 MeV

    International Nuclear Information System (INIS)

    Langevin-Joliot, H.; Van de Wiele, J.; Guillot, J.; Koning, A.J.

    2000-01-01

    The role of multi-step processes in the reactions 116 Sn(d,t), 208 Pb(d,t) and 116 Sn(d, 3 He), previously studied at E d = 200 MeV at forward angles and for relatively low energy transfers, has been investigated. We have performed for the first time multi-step calculations taking into account systematically collective excitations in the second and higher order step inelastic transitions. A calculation code based on the Feshbach, Kerman and Koonin model has been modified to handle explicitly these collective excitations, most important in the forward angle domain. One step double differential pick-up cross sections were built from finite range distorted wave results spread in energy using known or estimated hole state characteristics. It is shown that two-step cross sections calculated using the above method compare rather well with those deduced via coupled channel calculations for the same collective excitations. The multi-step calculations performed up to 6 steps reproduce reasonably well the 115 Sn, 207 Pb and 115 In experimental spectra measured up to E x ∼- 40 MeV and 15 deg. The relative contributions of steps of increasing order to pick-up cross sections at E d = 200 MeV and 150 MeV are discussed. (authors)

  15. Propensity approach to nonequilibrium thermodynamics of a chemical reaction network: controlling single E-coli β-galactosidase enzyme catalysis through the elementary reaction steps.

    Science.gov (United States)

    Das, Biswajit; Banerjee, Kinshuk; Gangopadhyay, Gautam

    2013-12-28

    In this work, we develop an approach to nonequilibrium thermodynamics of an open chemical reaction network in terms of the elementary reaction propensities. The method is akin to the microscopic formulation of the dissipation function in terms of the Kullback-Leibler distance of phase space trajectories in Hamiltonian system. The formalism is applied to a single oligomeric enzyme kinetics at chemiostatic condition that leads the reaction system to a nonequilibrium steady state, characterized by a positive total entropy production rate. Analytical expressions are derived, relating the individual reaction contributions towards the total entropy production rate with experimentally measurable reaction velocity. Taking a real case of Escherichia coli β-galactosidase enzyme obeying Michaelis-Menten kinetics, we thoroughly analyze the temporal as well as the steady state behavior of various thermodynamic quantities for each elementary reaction. This gives a useful insight in the relative magnitudes of various energy terms and the dissipated heat to sustain a steady state of the reaction system operating far-from-equilibrium. It is also observed that, the reaction is entropy-driven at low substrate concentration and becomes energy-driven as the substrate concentration rises.

  16. Expression of OCT4A: The First Step to the Next Stage of Urothelial Bladder Cancer Progression

    Directory of Open Access Journals (Sweden)

    Wojciech Jóźwicki

    2014-09-01

    Full Text Available OCT4 (octamer-binding transcription factor is a transcription factor responsible for maintaining the pluripotent properties of embryonic stem cells. In this paper, we present the results of studies to investigate the role of the OCT4 splicing variant in urothelial bladder cancer and the relationship between the OCT4 phenotype and the morphological parameters of tumor malignancy. Ninety patients who received a cystectomy for bladder cancer were enrolled. The expression of OCT4 protein was analyzed by immunohistochemistry. The ratio of OCT4-positive cells was the lowest in pT1 (pathological assessment (p—tumor extent confined to mucosa (T1 tumors and the highest in pTis (non-papillary tumor extent confined to urothelium and pT2 (tumor extent including muscularis propria tumors. Information about the percentage of OCT4A-positive tumor cells could facilitate choosing the treatment mode in borderline pTis–pT1 (crossing the border of the basement membrane; the first stage of progression and pT1–pT2 (crossing the border of the muscularis propria; the second stage of progression cases: a higher percentage of OCT4A-positive cells should support more radical therapy. A significantly higher percentage of cases with moderate OCT4 intensity was found in metastasizing (the third stage of progression cases with >2 positive lymph nodes. The percentage of OCT4-positive cells was significantly higher for cancers with a high grade, higher non-classic differentiation number and greater aggressiveness of invasion. The differentiation, maturation and aggressiveness of tumor invasion appear to depend on the expression of the OCT4 phenotype in cancer cells, similar to the successive stages of malignancy progression in urothelial cancer.

  17. Kinect-based choice reaching and stepping reaction time tests for clinical and in-home assessment of fall risk in older people: a prospective study.

    Science.gov (United States)

    Ejupi, Andreas; Gschwind, Yves J; Brodie, Matthew; Zagler, Wolfgang L; Lord, Stephen R; Delbaere, Kim

    2016-01-01

    Quick protective reactions such as reaching or stepping are important to avoid a fall or minimize injuries. We developed Kinect-based choice reaching and stepping reaction time tests (Kinect-based CRTs) and evaluated their ability to differentiate between older fallers and non-fallers and the feasibility of administering them at home. A total of 94 community-dwelling older people were assessed on the Kinect-based CRTs in the laboratory and were followed-up for falls for 6 months. Additionally, a subgroup (n = 20) conducted the Kinect-based CRTs at home. Signal processing algorithms were developed to extract features for reaction, movement and the total time from the Kinect skeleton data. Nineteen participants (20.2 %) reported a fall in the 6 months following the assessment. The reaction time (fallers: 797 ± 136 ms, non-fallers: 714 ± 89 ms), movement time (fallers: 392 ± 50 ms, non-fallers: 358 ± 51 ms) and total time (fallers: 1189 ± 170 ms, non-fallers: 1072 ± 109 ms) of the reaching reaction time test differentiated well between the fallers and non-fallers. The stepping reaction time test did not significantly discriminate between the two groups in the prospective study. The correlations between the laboratory and in-home assessments were 0.689 for the reaching reaction time and 0.860 for stepping reaction time. The study findings indicate that the Kinect-based CRT tests are feasible to administer in clinical and in-home settings, and thus represents an important step towards the development of sensor-based fall risk self-assessments. With further validation, the assessments may prove useful as a fall risk screen and home-based assessment measures for monitoring changes over time and effects of fall prevention interventions.

  18. Detection of Mycobacterium tuberculosis in clinical samples by two-step polymerase chain reaction and nonisotopic hybridization methods.

    OpenAIRE

    Shawar, R M; el-Zaatari, F A; Nataraj, A; Clarridge, J E

    1993-01-01

    Detection of Mycobacterium tuberculosis in clinical specimens by the polymerase chain reaction (PCR) was compared with detection by culture. A 317-bp segment within the M. tuberculosis-specific insertion sequence IS6110 was amplified. The detection limit of the PCR assay for cultured mycobacteria was 50 cells per reaction by ethidium bromide-stained agarose gel electrophoresis and 5 cells per reaction by hybridization with an oligonucleotide probe conjugated with either digoxigenin or alkalin...

  19. Synthesis of Programmable Main-chain Liquid-crystalline Elastomers Using a Two-stage Thiol-acrylate Reaction.

    Science.gov (United States)

    Saed, Mohand O; Torbati, Amir H; Nair, Devatha P; Yakacki, Christopher M

    2016-01-19

    This study presents a novel two-stage thiol-acrylate Michael addition-photopolymerization (TAMAP) reaction to prepare main-chain liquid-crystalline elastomers (LCEs) with facile control over network structure and programming of an aligned monodomain. Tailored LCE networks were synthesized using routine mixing of commercially available starting materials and pouring monomer solutions into molds to cure. An initial polydomain LCE network is formed via a self-limiting thiol-acrylate Michael-addition reaction. Strain-to-failure and glass transition behavior were investigated as a function of crosslinking monomer, pentaerythritol tetrakis(3-mercaptopropionate) (PETMP). An example non-stoichiometric system of 15 mol% PETMP thiol groups and an excess of 15 mol% acrylate groups was used to demonstrate the robust nature of the material. The LCE formed an aligned and transparent monodomain when stretched, with a maximum failure strain over 600%. Stretched LCE samples were able to demonstrate both stress-driven thermal actuation when held under a constant bias stress or the shape-memory effect when stretched and unloaded. A permanently programmed monodomain was achieved via a second-stage photopolymerization reaction of the excess acrylate groups when the sample was in the stretched state. LCE samples were photo-cured and programmed at 100%, 200%, 300%, and 400% strain, with all samples demonstrating over 90% shape fixity when unloaded. The magnitude of total stress-free actuation increased from 35% to 115% with increased programming strain. Overall, the two-stage TAMAP methodology is presented as a powerful tool to prepare main-chain LCE systems and explore structure-property-performance relationships in these fascinating stimuli-sensitive materials.

  20. Antioxidative Mechanisms of Sulfite and Protein-Derived Thiols during Early Stages of Metal Induced Oxidative Reactions in Beer.

    Science.gov (United States)

    Lund, Marianne N; Krämer, Anna C; Andersen, Mogens L

    2015-09-23

    The radical-mediated reactions occurring during the early stages of beer storage were studied by following the rate of oxygen consumption, radical formation as detected by electron spin resonance spectroscopy, and concentrations of the antioxidant compounds sulfite and thiols. Addition of either Fe(III) or Fe(II) had similar effects, indicating that a fast redox equilibrium is obtained between the two species in beer. Addition of iron in combination with hydrogen peroxide gave the most pronounced levels of oxidation due to a direct initiation of ethanol oxidation through generation of hydroxyl radicals by the Fenton reaction. The concentration of sulfite decreased more than the thiol concentration, suggesting that thiols play a secondary role as antioxidants by mainly quenching 1-hydroxyethyl radicals that are intermediates in the oxidation of ethanol. Increasing the temperature had a minor effect on the rate of oxygen consumption.

  1. Reorientation of the Methyl Group in MAs(III) is the Rate-Limiting Step in the ArsM As(III) S-Adenosylmethionine Methyltransferase Reaction.

    Science.gov (United States)

    Packianathan, Charles; Li, Jiaojiao; Kandavelu, Palani; Sankaran, Banumathi; Rosen, Barry P

    2018-03-01

    The most common biotransformation of trivalent inorganic arsenic (As(III)) is methylation to mono-, di-, and trimethylated species. Methylation is catalyzed by As(III) S -adenosylmethionine (SAM) methyltransferase (termed ArsM in microbes and AS3MT in animals). Methylarsenite (MAs(III)) is both the product of the first methylation step and the substrate of the second methylation step. When the rate of the overall methylation reaction was determined with As(III) as the substrate, the first methylation step was rapid, whereas the second methylation step was slow. In contrast, when MAs(III) was used as the substrate, the rate of methylation was as fast as the first methylation step when As(III) was used as the substrate. These results indicate that there is a slow conformational change between the first and second methylation steps. The structure of CmArsM from the thermophilic alga Cyanidioschyzon merolae sp. 5508 was determined with bound MAs(III) at 2.27 Å resolution. The methyl group is facing the solvent, as would be expected when MAs(III) is bound as the substrate rather than facing the SAM-binding site, as would be expected for MAs(III) as a product. We propose that the rate-limiting step in arsenic methylation is slow reorientation of the methyl group from the SAM-binding site to the solvent, which is linked to the conformation of the side chain of a conserved residue Tyr70.

  2. Do voluntary step reactions in dual task conditions have an added value over single task for fall prediction? A prospective study.

    Science.gov (United States)

    Melzer, Itshak; Kurz, Ilan; Shahar, Danit; Oddsson, Lars I E

    2010-01-01

    Stepping reactions play a critical role in responding to balance perturbations, whether they are a consequence of external perturbation or self-induced in nature. The aim of the present study was to determine prospectively the capacity of voluntary stepping performance in singleand dual-task conditions, to predict future falls among older community-dwelling persons. We also aimed to assess whether dual task conditions have an added value over single tasks for fall prediction. A total of 100 healthy old volunteers (mean age 78.4±5.7 yrs), from two self-care protected retirement homes for older adults, performed the Voluntary Step Execution Test in single- and dual-task conditions as a reaction time task while standing on a single force platform. Step initiation, preparatory and swing phases, and foot-contact time were extracted from data on center of pressure and ground reaction force. One-year fall incidences were monitored. Ninety-eight subjects completed the one-year follow-up, 49 non-fallers, 32 one-time fallers, and 17 recurrent fallers (two or more falls). Recurrent fallers had significantly slower voluntary step execution times in both single- and dual-task conditions, especially due to a slower preparation phase. Two stepwise (backward) logistic regression models showed that longer step execution times have strong predictive value for falls in both single- and dual-task conditions (odds ratio (OR) 8.7 and 5.4, respectively, ppredict future falls, with no added value to dual- over single-task condition.

  3. Inclusion of Sexual Orientation and Gender Identity in Stage 3 Meaningful Use Guidelines: A Huge Step Forward for LGBT Health.

    Science.gov (United States)

    Cahill, Sean R; Baker, Kellan; Deutsch, Madeline B; Keatley, Joanne; Makadon, Harvey J

    2016-04-01

    Final rules issued by the Centers for Medicare and Medicaid Services and the Office of the National Coordinator for Health Information Technology in October 2015 require electronic health record software certified for Meaningful Use to include sexual orientation and gender identity (SO/GI) fields. This is a critical step toward making SO/GI data collection a standard practice in clinical settings. Sexual orientation identity-whether one identifies as gay, lesbian, or bisexual-correlates with behavioral health burden, and it is important to collect these data. Providers should also collect sex assigned at birth data as well as current gender identity data. Training of clinical staff in collection and use of SO/GI data, education of LGBT patients, and SO/GI nondiscrimination policies are critical for successful implementation.

  4. Step-scan Fourier transform infrared (FTIR) spectrometer for investigating chemical reactions of energy-related materials. Final report, April 1, 1995--March 31, 1997

    Energy Technology Data Exchange (ETDEWEB)

    Eyring, E.M.

    1997-11-04

    Two step-scan Fourier transform infrared (FTIR) spectrometers were purchased with URI-DOE funds by the University of Utah. These infrared spectrometers have been used to carry out the following investigations: the determination of strength of adsorption of organic molecules at the liquid-solid interface of coated attenuated total reflectance (ATR) elements, the kinetic study of the photoinitiated polymerization of a dental resin, the exploration of the kinetics of photochemical reactions of organic molecules in solution, and the development of a stopped-flow FTIR interface for measuring rates and mechanisms of reactions in solution that are not photoinitiated and do not have convenient ultraviolet-visible spectral features.

  5. Clinical utility of simultaneous whole-body 18F-FDG PET/MRI as a single-step imaging modality in the staging of primary nasopharyngeal carcinoma.

    Science.gov (United States)

    Chan, Sheng-Chieh; Yeh, Chih-Hua; Yen, Tzu-Chen; Ng, Shu-Hang; Chang, Joseph Tung-Chieh; Lin, Chien-Yu; Yen-Ming, Tsang; Fan, Kang-Hsing; Huang, Bing-Shen; Hsu, Cheng-Lung; Chang, Kai-Ping; Wang, Hung-Ming; Liao, Chun-Ta

    2018-03-03

    Both head and neck magnetic resonance imaging (MRI) and 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET)/computed tomography (CT) play a crucial role in the staging of primary nasopharyngeal carcinoma (NPC). In this study, we sought to prospectively investigate the clinical utility of simultaneous whole-body 18F-FDG PET/MRI for primary staging of NPC patients. We examined 113 patients with histologically confirmed NPC who underwent pretreatment, simultaneous whole-body PET/MRI and PET/CT for primary tumor staging. The images obtained with the different imaging modalities were interpreted independently and compared with each other. PET/MRI increased the accuracy of head and neck MRI for assessment of primary tumor extent in four patients via addition of FDG uptake information to increase the conspicuity of morphologically subtle lesions. PET/MR images were more discernible than PET/CT images for mapping tumor extension, especially intracranial invasion. Regarding the N staging assessment, the sensitivity of PET/MRI (99.5%) was higher than that of head and neck MRI (94.2%) and PET/CT (90.9%). PET/MRI was particularly useful for distinguishing retropharyngeal nodal metastasis from adjacent nasopharyngeal tumors. For distant metastasis evaluation, PET/MRI exhibited a similar sensitivity (90% vs. 86.7% vs. 83.3%), but higher positive predictive value (93.1% vs. 78.8% vs. 83.3%) than whole-body MRI and PET/CT, respectively. For tumor staging of NPC, simultaneous whole-body PET/MRI was more accurate than head and neck MRI and PET/CT, and may serve as a single-step staging modality.

  6. Design and synthesis of fused polycycles via Diels–Alder reaction and ring-rearrangement metathesis as key steps

    Directory of Open Access Journals (Sweden)

    Sambasivarao Kotha

    2015-07-01

    Full Text Available Atom efficient processes such as the Diels–Alder reaction (DA and the ring-rearrangement metathesis (RRM have been used to design new polycycles. In this regard, ruthenium alkylidene catalysts are effective in realizing the RRM of bis-norbornene derivatives prepared by DA reaction and Grignard addition. Here, fused polycycles are assembled which are difficult to produce by conventional synthetic routes.

  7. Patterns of Adverse Transfusion Reactions in a Tertiary Care Centre of North India: A Step Towards Hemovigilance.

    Science.gov (United States)

    Bassi, Rajni; Aggarwal, Shikha; Bhardwaj, Kanchan; Thakur, Kusum K

    2017-06-01

    Transfusion of blood and blood products is a double edged sword, so it should be used judiciously. The primary aim of the centralized Haemovigilance Program is to improve transfusion safety. To determine the incidence of adverse transfusion reactions (ATRs) in recipients of blood and blood components. Prospective study from January 2014 till April 2015 was done. ATRs reported to the Department of Transfusion Medicine were recorded and analyzed on the basis of their clinical features and lab tests. During the study period 25,099 units of blood and blood components were transfused and 100 ATRs (0.40 %) were reported. The incidence of febrile nonhemolytic transfusion reactions (FNHTR) was maximum (73 %) followed by allergic reactions (24 %), bacterial sepsis (1 %), hypotension due to ACE inhibitors (1 %) and acute hemolytic transfusion reaction (AHTR) (1 %). Of all the reported ATRs, 76 % occurred with packed red cells, 15 % occurred with whole blood, while platelets and Fresh Frozen Plasma transfusions were responsible for 8 % and 1 %, respectively. The majority of the reactions were FNHTRs followed by allergic reactions. Reporting of all adverse events and continuous medical education to medical and paramedical staff will help in strengthening hemovigilance system.

  8. One-step fabrication of PEGylated fluorescent nanodiamonds through the thiol-ene click reaction and their potential for biological imaging

    Science.gov (United States)

    Huang, Hongye; Liu, Meiying; Tuo, Xun; Chen, Junyu; Mao, Liucheng; Wen, Yuanqing; Tian, Jianwen; Zhou, Naigen; Zhang, Xiaoyong; Wei, Yen

    2018-05-01

    Over the past years, fluorescent carbon nanoparticles have got growing interest for biological imaging. Fluorescent nanodiamonds (FNDs) are novel fluorescent carbon nanoparticles with multitudinous useful properties, including remarkable fluorescence properties, extremely low toxicity and high refractive index. However, facile preparation of FNDs with designable properties and functions from non-fluorescent detonation nanodiamonds (DNDs) has demonstrated to be challengeable. In this work, we reported for the first time that preparation of Polyethylene glycol (PEG) functionalized FNDs through a one-step thiol-ene click reaction using thiol containing PEG (PEG-SH) as the coating agent. Based on the characterization results, we demonstrated that PEG-SH could be efficiently introduced on DNDs to obtain FNDs through the thiol-ene click chemistry. The resultant FND-PEG composites showed high water dispersibility, strong fluorescence and low cytotoxicity. Moreover, FND-PEG composites could be internalized by cells and displayed good cell dyeing performance. All of these features implied that FND-PEG composites are of great potential for biological imaging. Taken together, a facile one-step strategy based on the one-step thiol-ene click reaction has been developed for efficient preparation of FND-PEG composites from non-fluorescent DNDs. The strategy should be also useful for fabrication of many other functional FNDs via using different thiol containing compounds for the universality of thiol-ene click reaction.

  9. Review of the Two-Step H2O/CO2-Splitting Solar Thermochemical Cycle Based on Zn/ZnO Redox Reactions

    Directory of Open Access Journals (Sweden)

    Aldo Steinfeld

    2010-11-01

    Full Text Available This article provides a comprehensive overview of the work to date on the two‑step solar H2O and/or CO2 splitting thermochemical cycles with Zn/ZnO redox reactions to produce H2 and/or CO, i.e., synthesis gas—the precursor to renewable liquid hydrocarbon fuels. The two-step cycle encompasses: (1 The endothermic dissociation of ZnO to Zn and O2 using concentrated solar energy as the source for high-temperature process heat; and (2 the non-solar exothermic oxidation of Zn with H2O/CO2 to generate H2/CO, respectively; the resulting ZnO is then recycled to the first step. An outline of the underlying science and the technological advances in solar reactor engineering is provided along with life cycle and economic analyses.

  10. Multiple Non-Thermal Reaction Steps for the Photooxidation CO to CO2 on Reduced TiO2(110)

    Energy Technology Data Exchange (ETDEWEB)

    Petrik, Nikolay G.; Kimmel, Gregory A.

    2013-02-07

    The photooxidation of CO on reduced, rutile TiO2(110) was studied on a millisecond timescale. For a saturation coverage of chemisorbed O2 (0sat) and for half that coverage, the CO2 photon-stimulated desorption (PSD) signal is initially zero, increases to a maximum after several tens of milliseconds, and then decreases at longer times. The CO2 PSD signal increases ~5 times more quickly for 0.50sat. The initial rate of increase of the CO2 PSD signal is proportional to the flux of UV photons. The intermediate species involved in the reactions is stable for at least 100 s at 30 K. These results show that two or more non-thermal reaction steps are required to photooxidize CO adsorbed on TiO2(110). In contrast, previous models had suggested that CO photooxidation required only one non-thermal reaction. The likely initial and final charge states of the system suggest that an electron-mediated reaction and a hole-mediated reaction are needed for the complete photooxidation reaction.

  11. Branched intermediate formation is the slowest step in the protein splicing reaction of the Ala1 KlbA intein from Methanococcus jannaschii.

    Science.gov (United States)

    Saleh, Lana; Southworth, Maurice W; Considine, Nancy; O'Neill, Colleen; Benner, Jack; Bollinger, J Martin; Perler, Francine B

    2011-12-13

    We report the first detailed investigation of the kinetics of protein splicing by the Methanococcus jannaschii KlbA (Mja KlbA) intein. This intein has an N-terminal Ala in place of the nucleophilic Cys or Ser residue that normally initiates splicing but nevertheless splices efficiently in vivo [Southworth, M. W., Benner, J., and Perler, F. B. (2000) EMBO J.19, 5019-5026]. To date, the spontaneous nature of the cis splicing reaction has hindered its examination in vitro. For this reason, we constructed an Mja KlbA intein-mini-extein precursor using intein-mediated protein ligation and engineered a disulfide redox switch that permits initiation of the splicing reaction by the addition of a reducing agent such as dithiothreitol (DTT). A fluorescent tag at the C-terminus of the C-extein permits monitoring of the progress of the reaction. Kinetic analysis of the splicing reaction of the wild-type precursor (with no substitutions in known nucleophiles or assisting groups) at various DTT concentrations shows that formation of the branched intermediate from the precursor is reversible (forward rate constant of 1.5 × 10(-3) s(-1) and reverse rate constant of 1.7 × 10(-5) s(-1) at 42 °C), whereas the productive decay of this intermediate to form the ligated exteins is faster and occurs with a rate constant of 2.2 × 10(-3) s(-1). This finding conflicts with reports about standard inteins, for which Asn cyclization has been assigned as the rate-determining step of the splicing reaction. Despite being the slowest step of the reaction, branched intermediate formation in the Mja KlbA intein is efficient in comparison with those of other intein systems. Interestingly, it also appears that this intermediate is protected against thiolysis by DTT, in contrast to other inteins. Evidence is presented in support of a tight coupling between the N-terminal and C-terminal cleavage steps, despite the fact that the C-terminal single-cleavage reaction occurs in variant Mja KlbA inteins in

  12. Synthesis of the reported structure of piperazirum using a nitro-Mannich reaction as the key stereochemical determining step

    Directory of Open Access Journals (Sweden)

    James C. Anderson

    2013-08-01

    Full Text Available Piperazirum, isolated from Arum palaestinum Boiss, was originally assigned as r-3,c-5-diisobutyl-c-6-isopropylpiperazin-2-one. The reported structure was synthesised diastereoselectively using a key nitro-Mannich reaction to set up the C5/C6 relative stereochemistry. The structure was unambiguously assigned by single crystal X-ray diffraction but the spectroscopic data did not match those reported for the natural product. The structure of the natural product must therefore be revised.

  13. Cluster emission at pre-equilibrium stage in Heavy Nuclear Reactions. A Model considering the Thermodynamics of Small Systems

    International Nuclear Information System (INIS)

    Bermudez Martinez, A.; Damiani, D.; Guzman Martinez, F.; Rodriguez Hoyos, O.; Rodriguez Manso, A.

    2015-01-01

    Cluster emission at pre-equilibrium stage, in heavy ion fusion reactions of 12 C and 16 O nuclei with 116 Sn, 208 Pb, 238 U are studied. the energy of the projectile nuclei was chosen at 0.25GeV, 0.5GeV and 1GeV. A cluster formation model is developed in order to calculate the cluster size. Thermodynamics of small systems was used in order to examine the cluster behavior inside the nuclear media. This model is based on considering two phases inside the compound nucleus, on one hand the nuclear media phase, and on the other hand the cluster itself. The cluster acts like an instability inside the compound nucleus, provoking an exchange of nucleons with the nuclear media through its surface. The processes were simulated using Monte Carlo methods. We obtained that the cluster emission probability shows great dependence on the cluster size. This project is aimed to implement cluster emission processes, during the pre-equilibrium stage, in the frame of CRISP code (Collaboration Rio-Sao Paulo). (Author)

  14. Influence of the reaction conditions on the enzyme catalyzed transesterification of castor oil: A possible step in biodiesel production.

    Science.gov (United States)

    Andrade, Thalles A; Errico, Massimiliano; Christensen, Knud V

    2017-11-01

    The identification of the influence of the reaction parameters is of paramount importance when defining a process design. In this work, non-edible castor oil was reacted with methanol to produce a possible component for biodiesel blends, using liquid enzymes as the catalyst. Temperature, alcohol-to-oil molar ratio, enzyme and added water contents were the reaction parameters evaluated in the transesterification reactions. The optimal conditions, giving the optimal final FAME yield and FFA content in the methyl ester-phase was identified. At 35°C, 6.0 methanol-to-oil molar ratio, 5wt% of enzyme and 5wt% of water contents, 94% of FAME yield and 6.1% of FFA in the final composition were obtained. The investigation was completed with the analysis of the component profiles, showing that at least 8h are necessary to reach a satisfactory FAME yield together with a minor FFA content. Copyright © 2017 Elsevier Ltd. All rights reserved.

  15. Spatially resolved product formation in the reaction of formic acid with calcium carbonate (1014): the role of step density and adsorbed water-assisted ion mobility.

    Science.gov (United States)

    Usher, Courtney R; Baltrusaitis, Jonas; Grassian, Vicki H

    2007-06-19

    The reaction of calcium carbonate (1014) single-crystal surfaces with formic acid (HCOOH) vapor was investigated using atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). AFM images indicate the reaction produces rather well-defined crystallites, preferentially at step edges and at distinct angles to one another and mirroring the rhombohedral structure of the calcite surface, while exposing unreacted carbonate surface. The size and surface density of the crystallites depend upon substrate step density, exposure time, and relative humidity. XPS data confirmed the crystallite composition as the expected calcium formate product. The AFM images show erosion and pit formation of the calcite surface in the vicinity of the product crystallites, clearly providing the spatially resolved characterization of the source of Ca ions. AFM experiments exploring the effects of water vapor on the reacted surface show that the calcium formate crystallites are mobile under conditions of high relative humidity, combining to form larger crystallites and nanometer-sized crystals with an orthorhombohedral habit consistent with the alpha form, as confirmed by X-ray diffraction. The implications for the reactions described here are discussed.

  16. Arresting Consecutive Steps of a Photochromic Reaction: Studies of β-Thioxoketones Combining Laser Photolysis with NMR Detection

    DEFF Research Database (Denmark)

    Pietrzak, Mariusz; Dobkowski, Jacek; Gorski, Alexandr

    2014-01-01

    of the back reaction. These observations, along with the data obtained using electronic and vibrational spectroscopies for rare gas matrix-isolated samples, glasses, polymers, and solutions, as well as the results of quantum-chemical calculations, provide insight into the stepwise mechanism...... depends on the excitation wavelength. Analysis of the mechanisms of the photochromic processes indicates a state-specific precursor: chelated thione–enol form in the excited S2(ππ*) electronic state. The results show the potential of using laser photolysis coupled with NMR detection for the identification...

  17. The role of MgCl2 compounds in preparation of Tin oxide micro particles by one-step solid - state chemical reaction method and characterization of microstructure

    International Nuclear Information System (INIS)

    Hojabry, A.; Rezainik, Y.; Abdoljavad, N.; Moghimi, N.; Shakib, M.

    2007-01-01

    In this paper, Tin oxide (SnO 2 ) nano crystals have been synthesized by one-step solid-state chemical reactions method. In the first step, the powder of SnCl 4 . 5H 2 O was mixed with MgCl 2 and Mg(OH) 2 with a weight ratio of Sn to Mg (2:1) in the air atmosphere at room, and then annealed at 200 d egree C , 400 d egree C and 600 d egree C in air for 4 h to give different size of nanoparticles. This method is a simple, efficient and economic preparation for SnO 2 nanoparticles with adjustable grain sizes in the range of 7-32 nm in high yield. The microstructure and morphology of SnO 2 nanoparticles have been studied by X-ray diffraction (XRD), scanning electron microscopy and thermal analysis (thermogravimetric analysis -differential thermal analysis).

  18. Standardization of a two-step real-time polymerase chain reaction based method for species-specific detection of medically important Aspergillus species

    Directory of Open Access Journals (Sweden)

    P Das

    2017-01-01

    Full Text Available Purpose: Standardization of Aspergillus polymerase chain reaction (PCR poses two technical challenges (a standardization of DNA extraction, (b optimization of PCR against various medically important Aspergillus species. Many cases of aspergillosis go undiagnosed because of relative insensitivity of conventional diagnostic methods such as microscopy, culture or antigen detection. The present study is an attempt to standardize real-time PCR assay for rapid sensitive and specific detection of Aspergillus DNA in EDTA whole blood. Materials and Methods: Three nucleic acid extraction protocols were compared and a two-step real-time PCR assay was developed and validated following the recommendations of the European Aspergillus PCR Initiative in our setup. In the first PCR step (pan-Aspergillus PCR, the target was 28S rDNA gene, whereas in the second step, species specific PCR the targets were beta-tubulin (for Aspergillus fumigatus, Aspergillus flavus, Aspergillus terreus, gene and calmodulin gene (for Aspergillus niger. Results: Species specific identification of four medically important Aspergillus species, namely, A. fumigatus, A. flavus, A. niger and A. terreus were achieved by this PCR. Specificity of the PCR was tested against 34 different DNA source including bacteria, virus, yeast, other Aspergillus sp., other fungal species and for human DNA and had no false-positive reactions. The analytical sensitivity of the PCR was found to be 102 CFU/ml. Conclusion: The present protocol of two-step real-time PCR assays for genus- and species-specific identification for commonly isolated species in whole blood for diagnosis of invasive Aspergillus infections offers a rapid, sensitive and specific assay option and requires clinical validation at multiple centers.

  19. Standardization of a two-step real-time polymerase chain reaction based method for species-specific detection of medically important Aspergillus species.

    Science.gov (United States)

    Das, P; Pandey, P; Harishankar, A; Chandy, M; Bhattacharya, S; Chakrabarti, A

    2017-01-01

    Standardization of Aspergillus polymerase chain reaction (PCR) poses two technical challenges (a) standardization of DNA extraction, (b) optimization of PCR against various medically important Aspergillus species. Many cases of aspergillosis go undiagnosed because of relative insensitivity of conventional diagnostic methods such as microscopy, culture or antigen detection. The present study is an attempt to standardize real-time PCR assay for rapid sensitive and specific detection of Aspergillus DNA in EDTA whole blood. Three nucleic acid extraction protocols were compared and a two-step real-time PCR assay was developed and validated following the recommendations of the European Aspergillus PCR Initiative in our setup. In the first PCR step (pan-Aspergillus PCR), the target was 28S rDNA gene, whereas in the second step, species specific PCR the targets were beta-tubulin (for Aspergillus fumigatus, Aspergillus flavus, Aspergillus terreus), gene and calmodulin gene (for Aspergillus niger). Species specific identification of four medically important Aspergillus species, namely, A. fumigatus, A. flavus, A. niger and A. terreus were achieved by this PCR. Specificity of the PCR was tested against 34 different DNA source including bacteria, virus, yeast, other Aspergillus sp., other fungal species and for human DNA and had no false-positive reactions. The analytical sensitivity of the PCR was found to be 102 CFU/ml. The present protocol of two-step real-time PCR assays for genus- and species-specific identification for commonly isolated species in whole blood for diagnosis of invasive Aspergillus infections offers a rapid, sensitive and specific assay option and requires clinical validation at multiple centers.

  20. Nanocellulose steps up on stage

    Energy Technology Data Exchange (ETDEWEB)

    McCormick, C.

    2010-07-15

    Canadian researchers and manufacturers are world leaders in the development of new applications for nanocellulose, a principal component of trees. Nanocrystalline cellulose (NCC) is a natural substance first isolated in 1949. The cellulose in pulp is approximately 70 per cent NCC. Canadian researchers have found a way to extract NCC from wood in industrial quantities. A batch process has been developed at a demonstration plant in Windsor. Other researchers are now developing new NCC applications for strengthening wood varnish, improving paint texture, and adding it to polymers for additional strength. A consortium of industry partners and researchers are now preparing joint agreements with manufacturers to investigate wood coatings and composites; improve NCC's compatibility with polymers; and examine applications of its optical properties in pulp and paper processes. NCC may also be used in aircraft design as well as in automotive products. 1 fig.

  1. Identification of Veillonella Species in the Tongue Biofilm by Using a Novel One-Step Polymerase Chain Reaction Method

    Science.gov (United States)

    Mashima, Izumi; Theodorea, Citra Fragrantia; Thaweboon, Boonyanit; Thaweboon, Sroisiri; Nakazawa, Futoshi

    2016-01-01

    Six Veillonella species have been frequently isolated from human oral cavities including infectious sites. Recently, it was reported that diet, smoking, and possibly socioeconomic status can influence the bacterial profile in oral cavities. In addition, oral hygiene habits may also influence oral microbiota in terms of both numbers and diversity of microorganisms. In this study, the identification of Veillonella species in tongue biofilms of Thai children, divided into three groups dependent on their status of oral hygiene. For this, we used a novel one-step PCR method with species-specific primer sets based on sequences of the rpoB gene. As shown in the results, the number of isolates of Veillonella species was 101 strains from only 10 of 89 subjects. However, the total number of bacteria was high for all subjects. Since it was reported in previous studies that Veillonella species were easy to isolate in human tongue biofilms at high numbers, the results obtained in this study may suggest country- or age-specific differences. Moreover, Veillonella species were detected predominantly in subjects who had poor oral hygiene compared to those with good or moderate oral hygiene. From these results, there is a possibility that Veillonella species may be an index of oral hygiene status. Furthermore, V. rogosae was a predominant species in tongue biofilms of Thai children, whereas V. parvula and V. denticariosi were not isolated at all. These characteristics of the distribution and frequency of Veillonella species are similar to those reported in previous studies. Although further studies are needed in other countries, in this study, a successful novel one-step PCR method was established to detect Veillonella species in human oral cavities easily and effectively. Furthermore, this is the first report investigating the distribution and frequency of Veillonella species in tongue biofilms of Thai children. PMID:27326455

  2. SU-F-T-356: DosimetricComparison of VMAT Vs Step and Shoot IMRT Plans for Stage III Lung CancerPatients with Mediastinal Involvement

    Energy Technology Data Exchange (ETDEWEB)

    Pearson, D; Bogue, J [University of Toledo, Toledo, OH (United States)

    2016-06-15

    Purpose: For Stage III lung cancers that entail treatment of some or all of the mediastinum, anterior-posterior focused Step and Shoot IMRT (SS-IMRT) and VMAT plans have been clinically used to deliver the prescribed dose while working to minimize lung dose and avoid other critical structures. A comparison between the two planning methods was completed to see which treatment method is superior and minimizes dose to healthy lung tissue. Methods: Ten patients who were recently treated with SS-IMRT or VMAT plans for Stage III lung cancer with mediastinal involvement were selected. All patients received a simulation CT for treatment planning, as well as a 4D CT and PET/CT fusion for target delineation. Plans were prescribed 6250 cGy in 25 fractions and normalized such that 100% of the prescription dose covered 95% of the PTV. Clinically approved SS-IMRT or VMAT plans were then copied and planned using the alternative modality with identical optimization criteria. SS-IMRT plans utilized seven to nine beams distributed around the patient while the VMAT plans consisted of two full 360 degree arcs. Plans were compared for the lung volume receiving 20 Gy (V20). Results: Both SS-IMRT and VMAT can be used to achieve clinical treatment plans for patients with Stage III Lung cancer with targets encompassing the mediastinum. VMAT plans produced an average V20 of 23.0+/−8.3% and SS-IMRT produced an average of 24.2+/−10.0%. Conclusion: Results indicate that either method can achieve comparable dose distributions, however, VMAT can allow the optimizer to distribute dose over paths of minimal lung tissue and reduce the V20. Therefore, creating a VMAT with constraints identical to an SS-IMRT plan could help to reduce the V20 in clinical treatment plans.

  3. Fabrication of a Microbial Biosensor Based on QD-MWNT Supports by a One-Step Radiation Reaction and Detection of Phenolic Compounds in Red Wines

    Directory of Open Access Journals (Sweden)

    Seong-Ho Choi

    2011-02-01

    Full Text Available An Acaligense sp.-immobilized biosensor was fabricated based on QD-MWNT composites as an electron transfer mediator and a microbe immobilization support by a one-step radiation reaction and used for sensing phenolic compounds in commercial red wines. First, a quantum dot-modified multi-wall carbon nanotube (QD-MWNT composite was prepared in the presence of MWNT by a one-step radiation reaction in an aqueous solution at room temperature. The successful preparation of the QD-MWNT composite was confirmed by XPS, TEM, and elemental analysis. Second, the microbial biosensor was fabricated by immobilization of Acaligense sp. on the surface of the composite thin film of a glassy carbon (GC electrode, which was prepared by a hand casting method with a mixture of the previously obtained composite and Nafion solution. The sensing ranges of the microbial biosensor based on CdS-MWNT and Cu2S-MWNT supports were 0.5–5.0 mM and 0.7–10 mM for phenol in a phosphate buffer solution, respectively. Total concentration of phenolic compounds contained in commercial red wines was also determined using the prepared microbial immobilized biosensor.

  4. Single-molecule Imaging Analysis of Elementary Reaction Steps of Trichoderma reesei Cellobiohydrolase I (Cel7A) Hydrolyzing Crystalline Cellulose Iα and IIII*

    Science.gov (United States)

    Shibafuji, Yusuke; Nakamura, Akihiko; Uchihashi, Takayuki; Sugimoto, Naohisa; Fukuda, Shingo; Watanabe, Hiroki; Samejima, Masahiro; Ando, Toshio; Noji, Hiroyuki; Koivula, Anu; Igarashi, Kiyohiko; Iino, Ryota

    2014-01-01

    Trichoderma reesei cellobiohydrolase I (TrCel7A) is a molecular motor that directly hydrolyzes crystalline celluloses into water-soluble cellobioses. It has recently drawn attention as a tool that could be used to convert cellulosic materials into biofuel. However, detailed mechanisms of action, including elementary reaction steps such as binding, processive hydrolysis, and dissociation, have not been thoroughly explored because of the inherent challenges associated with monitoring reactions occurring at the solid/liquid interface. The crystalline cellulose Iα and IIII were previously reported as substrates with different crystalline forms and different susceptibilities to hydrolysis by TrCel7A. In this study, we observed that different susceptibilities of cellulose Iα and IIII are highly dependent on enzyme concentration, and at nanomolar enzyme concentration, TrCel7A shows similar rates of hydrolysis against cellulose Iα and IIII. Using single-molecule fluorescence microscopy and high speed atomic force microscopy, we also determined kinetic constants of the elementary reaction steps for TrCel7A against cellulose Iα and IIII. These measurements were performed at picomolar enzyme concentration in which density of TrCel7A on crystalline cellulose was very low. Under this condition, TrCel7A displayed similar binding and dissociation rate constants for cellulose Iα and IIII and similar fractions of productive binding on cellulose Iα and IIII. Furthermore, once productively bound, TrCel7A processively hydrolyzes and moves along cellulose Iα and IIII with similar translational rates. With structural models of cellulose Iα and IIII, we propose that different susceptibilities at high TrCel7A concentration arise from surface properties of substrate, including ratio of hydrophobic surface and number of available lanes. PMID:24692563

  5. A diagnostic one-step real-time reverse transcription polymerase chain reaction method for accurate detection of influenza virus type A.

    Science.gov (United States)

    Behzadi, Mohammad Amin; Ziyaeyan, Mazyar; Alborzi, Abdolvahab

    2016-12-01

    Influenza A is known as a public health concern worldwide. In this study, a novel one-step real-time reverse transcription polymerase chain reaction (rtRT-PCR) assay was designed and optimized for the detection of influenza A viruses. The primers and probe were designed based on the analysis of 90 matrix nucleotide sequence data of influenza type A subtypes from the GenBank database of the National Center for Biotechnology Information (NCBI). The influenza virus A/Tehran/5652/2010 (H1N1 pdm09) was used as a reference. The rtRT-PCR assay was optimized, compared with that of the World Health Organization (WHO), and its analytical sensitivity, specificity and reproducibility were evaluated. In total, 64 nasopharyngeal swabs from patients with influenza-like illness (ILI) and 41 samples without ILI symptoms were tested for the virus, using conventional cell culture, direct immunofluorescence antibody (DFA) methods, and one-step rtRT-PCR with the designed primer set and probe and the WHO's. The optimized assay results were similar to the WHO's. The optimized assay results were similar to WHO's, with non-significant differences for 10-10 3 copies of viral RNA/reaction ( p > 0.05). It detected 10 copies of viral RNA/reaction with high reproducibility and no cross reactivity with other respiratory viruses. A specific cytopathic effect was observed in 6/64 (9.37%) of the ILI group using conventional culture and DFA staining methods; however, it was not seen in non-ILI. Also, the results of our assay and the WHO's were similar to those of viral isolation and DFA staining. Given the high specificity, sensitivity and reproducibility of this novel assay, it can serve as a reliable diagnostic tool for the detection of influenza A viruses in clinical specimens and lab experiments.

  6. Single-Tube Reaction Using Perfluorocarbons: A Prerequisite Step Leading to the Whole-Slide In Situ Technique on Histopathological Slides.

    Directory of Open Access Journals (Sweden)

    Yi-Chang Chen

    Full Text Available Developing a robust, novel method for performing multiple reactions in a single tube is not only time- and cost-saving but also critical for future high-throughput whole-slide in situ techniques on diseased tissues. In this study, we introduce the use of perfluorocarbons and compound-coated magnetic particles to create pseudochambers in a single tube, allowing different reactions to be performed in different phases. Perfluorocarbons also serve as cell lysis buffer and polymerase chain reaction (PCR buffer owing to their highly penetrating, repellent and emulsifiable properties. Using this method, nucleic acids can be isolated and purified from various sample types and sizes, followed by PCR, real-time PCR, or multiplex PCR in the same tube. No incubation or enzyme digesting time is needed and the risk of cross-contamination is reduced. Tests can be performed in microemulsions (water-in-oil droplets containing sequence-specific captures and probes for further high-throughput detection. We present a simple, quick, and robust procedure as a prerequisite step to future high-throughput in situ techniques.

  7. Mechanisms of free-radical reactions. XXI. Stereoselectivity of the hydrogen abstraction and chlorine transfer stages in the free-radical chlorination of norbornane by (dichloroiodo) arenes

    International Nuclear Information System (INIS)

    Dneprovskii, A.S.; Pertsikov, B.Z.

    1987-01-01

    The free-radical chlorination of stereospecifically deuterated norbornane by (dichloroiodo) arenes was studied by the method of competing reactions and by PMR and mass spectroscopy. The hydrogen abstraction stage is realized with preferential cleavage of the exo-C-H bond. exo-2-Chloronorbornane is formed preferentially at the stage of transfer of the chlorine atom to the 2-norbornyl radical. The nature of the stereoselectivity in both stages and the relationships governing its variation with variation in the structure of the chlorinating agent are determined by steric interactions which appear in the transition state

  8. Precipitation Stages and Reaction Kinetics of AlMgSi Alloys during the Artificial Aging Process Monitored by In-Situ Electrical Resistivity Measurement Method

    Directory of Open Access Journals (Sweden)

    Hong He

    2018-01-01

    Full Text Available The precipitation process and reaction kinetics during artificial aging, precipitate microstructure, and mechanical properties after aging of AlMgSi alloys were investigated employing in-situ electrical resistivity measurement, Transmission Electron Microscopy (TEM observation, and tensile test methods. Three aging stages in sequence, namely formation of GP zones, transition from GP zones to β″ phase, transition from β″ to β′ phase, and coarsening of both phases, were clearly distinguished by the variation of the resistivity. It was discussed together with the mechanical properties and precipitate morphology evolution. Fast formation of GP zones and β″ phase leads to an obvious decrease of the resistivity and increase of the mechanical strength. The formation of β″ phase in the second stage, which contributes to the peak aging strength, has much higher reaction kinetics than reactions in the other two stages. All of these stages finished faster with higher reaction kinetics under higher temperatures, due to higher atom diffusion capacity. The results proved that the in-situ electrical resistivity method, as proposed in the current study, is a simple, effective, and convenient technique for real-time monitoring of the precipitation process of AlMgSi alloys. Its further application for industrial production and scientific research is also evaluated.

  9. A family of four stages embedded explicit six-step methods with eliminated phase-lag and its derivatives for the numerical solution of the second order problems

    Science.gov (United States)

    Simos, T. E.

    2017-11-01

    A family of four stages high algebraic order embedded explicit six-step methods, for the numerical solution of second order initial or boundary-value problems with periodical and/or oscillating solutions, are studied in this paper. The free parameters of the new proposed methods are calculated solving the linear system of equations which is produced by requesting the vanishing of the phase-lag of the methods and the vanishing of the phase-lag's derivatives of the schemes. For the new obtained methods we investigate: • Its local truncation error (LTE) of the methods.• The asymptotic form of the LTE obtained using as model problem the radial Schrödinger equation.• The comparison of the asymptotic forms of LTEs for several methods of the same family. This comparison leads to conclusions on the efficiency of each method of the family.• The stability and the interval of periodicity of the obtained methods of the new family of embedded finite difference pairs.• The applications of the new obtained family of embedded finite difference pairs to the numerical solution of several second order problems like the radial Schrödinger equation, astronomical problems etc. The above applications lead to conclusion on the efficiency of the methods of the new family of embedded finite difference pairs.

  10. Two-step multiplex polymerase chain reaction improves the speed and accuracy of genotyping using DNA from noninvasive and museum samples.

    Science.gov (United States)

    Arandjelovic, M; Guschanski, K; Schubert, G; Harris, T R; Thalmann, O; Siedel, H; Vigilant, L

    2009-01-01

    Many studies in molecular ecology rely upon the genotyping of large numbers of low-quantity DNA extracts derived from noninvasive or museum specimens. To overcome low amplification success rates and avoid genotyping errors such as allelic dropout and false alleles, multiple polymerase chain reaction (PCR) replicates for each sample are typically used. Recently, two-step multiplex procedures have been introduced which drastically increase the success rate and efficiency of genotyping. However, controversy still exists concerning the amount of replication needed for suitable control of error. Here we describe the use of a two-step multiplex PCR procedure that allows rapid genotyping using at least 19 different microsatellite loci. We applied this approach to quantified amounts of noninvasive DNAs from western chimpanzee, western gorilla, mountain gorilla and black and white colobus faecal samples, as well as to DNA from ~100-year-old gorilla teeth from museums. Analysis of over 45 000 PCRs revealed average success rates of > 90% using faecal DNAs and 74% using museum specimen DNAs. Average allelic dropout rates were substantially reduced compared to those obtained using conventional singleplex PCR protocols, and reliable genotyping using low (< 25 pg) amounts of template DNA was possible. However, four to five replicates of apparently homozygous results are needed to avoid allelic dropout when using the lowest concentration DNAs (< 50 pg/reaction), suggesting that use of protocols allowing routine acceptance of homozygous genotypes after as few as three replicates may lead to unanticipated errors when applied to low-concentration DNAs. © 2008 The Authors. Journal compilation © 2008 Blackwell Publishing Ltd.

  11. Two-step bacterial broad-range polymerase chain reaction analysis of heart valve tissue improves bacteriological diagnosis of infective endocarditis.

    Science.gov (United States)

    Boussier, Rémi; Rogez, Sylvie; François, Bruno; Denes, Eric; Ploy, Marie-Cécile; Garnier, Fabien

    2013-03-01

    Positive heart valve (HV) culture is a major Duke's criterion for the diagnosis of infective endocarditis but is poorly sensitive. Two broad-range 16S rDNA polymerase chain reaction (PCR) methods were applied to 31 HV samples: first, a real-time method, then conventional end-point PCR was applied to HV samples on which the first PCR was negative. Five specific real-time PCR procedures were also used in order to identify Bartonella spp., Tropheryma whipplei, Chlamydophila pneumoniae, Mycoplasma pneumonia, and Coxiella burnetii. A strategy combining the 2-step broad-range PCR methods improved the sensitivity of the molecular method from 38.7% to 58%. Specific PCR identified 1 T. whipplei, which was also identified by conventional end-point PCR. These results confirm that blood culture is the gold standard for the diagnosis of infective endocarditis, shows that molecular methods applied to HV can be useful when blood culture is negative, and that 2-step broad-range PCR approach seems to be more sensitive. Copyright © 2013 Elsevier Inc. All rights reserved.

  12. Stage design

    International Nuclear Information System (INIS)

    Shacter, J.

    1975-01-01

    A method is described of cycling gases through a plurality of diffusion stages comprising the steps of admitting the diffused gases from a first diffusion stage into an axial compressor, simultaneously admitting the undiffused gases from a second diffusion stage into an intermediate pressure zone of said compressor corresponding in pressure to the pressure of said undiffused gases, and then admitting the resulting compressed mixture of diffused and undiffused gases into a third diffusion stage

  13. A new use of hydroxyapatite-based consolidant: cleaning and consolidation of stones in one step by reaction with gypsum crust

    Science.gov (United States)

    Molina Piernas, Eduardo; Rueda Quero, Lucia; Cultrone, Giuseppe; Ruiz Agudo, Encarnación

    2015-04-01

    The reaction between diammonium hydrogen phosphate (DAP) and calcite in the stone to form hydroxyapatite (HAP) had provided a new product to consolidate limestone or Ca-rich stones, for example sandstones with carbonatic cement. However, what does it happen with the stones without Ca-bearing compounds? Obviously, HAP cannot form. In the other hand, recent research about consolidation with DAP show a good interaction between carbonatic stones and HAP, improving their mechanical properties. For these reasons, we propose a new method for the consolidation of building stone capable of cleaning the gypsum crust and consolidating stones at the same time, based in the Ferroni-Dini method [1] and using DAP. Based on this method, we aim at obtaining a consolidating component reacting DAP (instead of ammonium carbonate) and the gypsum contained in the crust of weathered stones in polluted environments. As an advantage, we do not need to use barium hydroxide (the second step required in the Ferroni-Dini method), thereby reducing the time necessary to carry out the consolidation. Here, we report different tests to evaluate this new procedure. In a first set of experiments, a DAP solution was poured on a gypsum (dihydrate calcium sulphate) saturated solution and by monitoring the free calcium content of the solution using an ion-selective electrode we have evaluated the fluctuations in the content in calcium of the solution and the speed of the reaction. Once the reaction finished, we analyzed the solids formed to verify the formation of hydroxyapatite by FTIR and microRAMAN. The second test consisted in the alteration of limestone blocks with sulfuric acid to obtain a crust of gypsum and, after that, the samples were consolidated by means of cellulose compress soaked in DAP 3M during different reaction times (30 minutes, 1 hour and 4 hours, at controlled temperature -20 °C- and relative humidity -40% HR-). The samples were then analyzed by XRD, FTIR, microRAMAN and SEM-EDX to

  14. Rapid detection and quantification of Ebola Zaire virus by one-step real-time quantitative reverse transcription-polymerase chain reaction.

    Science.gov (United States)

    Ro, Young-Tae; Ticer, Anysha; Carrion, Ricardo; Patterson, Jean L

    2017-04-01

    Given that Ebola virus causes severe hemorrhagic fever in humans with mortality rates as high as 90%, rapid and accurate detection of this virus is essential both for controlling infection and preventing further transmission. Here, a one-step qRT-PCR assay for rapid and quantitative detection of an Ebola Zaire strain using GP, VP24 or VP40 genes as a target is introduced. Routine assay conditions for hydrolysis probe detection were established from the manufacturer's protocol used in the assays. The analytical specificity and sensitivity of each assay was evaluated using in vitro synthesized viral RNA transcripts. The assays were highly specific for the RNA transcripts, no cross-reactivity being observed among them. The limits of detection of the assays ranged from 10 2 to 10 3 copies per reaction. The assays were also evaluated using viral RNAs extracted from cell culture-propagated viruses (Ebola Zaire, Sudan and Reston strains), confirming that they are gene- and strain-specific. The RT-PCR assays detected viral RNAs in blood samples from virus-infected animal, suggesting that they can be also a useful method for identifying Ebola virus in clinical samples. © 2017 The Societies and John Wiley & Sons Australia, Ltd.

  15. One-Step Growth of Iron-Nickel Bimetallic Nanoparticles on FeNi Alloy Foils: Highly Efficient Advanced Electrodes for the Oxygen Evolution Reaction.

    Science.gov (United States)

    Qazi, Umair Yaqub; Yuan, Cheng-Zong; Ullah, Naseeb; Jiang, Yi-Fan; Imran, Muhammad; Zeb, Akif; Zhao, Sheng-Jie; Javaid, Rahat; Xu, An-Wu

    2017-08-30

    Electrochemical water splitting is an important process to produce hydrogen and oxygen for energy storage and conversion devices. However, it is often restricted by the oxygen evolution reaction (OER) due to its sluggish kinetics. To overcome the problem, precious metal oxide-based electrocatalysts, such as RuO 2 and IrO 2 , are widely used. The lack of availability and the high cost of precious metals compel researchers to find other resources for the development of cost-effective, environmentally friendly, earth-abundant, nonprecious electrocatalysts for OER. Such catalysts should have high OER performance and good stability in comparison to those of available commercial precious metal-based electrocatalysts. Herein, we report an inexpensive fabrication of bimetallic iron-nickel nanoparticles on FeNi-foil (FeNi 4.34 @FeNi-foil) as an integrated OER electrode using a one-step calcination process. FeNi 4.34 @FeNi-foil obtained at 900 °C shows superior OER activity in alkaline solution with an overpotential as low as 283 mV to achieve a current density of 10 mA cm -2 and a small Tafel slope of 53 mV dec -1 . The high performance and durability of the as-prepared nonprecious metal electrode even exceeds those of the available commercial RuO 2 and IrO 2 catalysts, showing great potential in replacing the expensive noble metal-based electrocatalysts for OER.

  16. Intensity of cervical inflammatory reaction as a risk factor for recurrence of carcinoma of the uterine cervix in stages IB and IIA

    Directory of Open Access Journals (Sweden)

    José Humberto Tavares Guerreiro Fregnani

    Full Text Available CONTEXT AND OBJECTIVE: Inflammatory reaction intensity has been indicated as a possible recurrence risk factor in carcinoma of the uterine cervix. Some authors observed greater risk with weak inflammatory reaction, while others described the opposite. This study aimed to evaluate risk factors for initial-stage uterine cervix carcinoma recurrence (IB and IIA, considering inflammatory reaction intensity. DESIGN AND SETTING: Retrospective cohort at Hospital do Câncer A. C. Camargo. METHODS: 289 patients with diagnosed uterine cervix carcinoma (stages IB and IIA who underwent radical surgery between 1980 and 1999 were studied. Data were collected from medical records. Histological sections from tumors and lymph nodes could be reviewed in 247 cases. Five-year disease-free survival rates were calculated using the Kaplan-Meier method and curves were compared using the log-rank test. Cox's proportional-hazards model was used for multivariate analysis. Recurrence risk was estimated using hazard ratios (HR. RESULTS: Forty-three recurrences were found. Multivariate analysis identified the following independent recurrence risk factors: number of metastatic pelvic lymph nodes (one lymph node: HR = 3.3 [1.3-8.3]; two or three: HR = 5.3 [1.5-18.6]; four or more: HR = 7.6 [1.7-33.2], tumor invasion depth (deepest third: HR = 2.1 [1.1-4.1] and inflammatory reaction intensity in the uterine cervix (absent or slight: HR = 2.5 [1.1-5.7]. CONCLUSION: This study identified that absent or slight inflammatory reaction was an independent risk factor for recurrence. The other risk factors were the number of metastatic pelvic lymph nodes and invasion of the deepest third of the uterine cervix.

  17. Protonation mechanism and location of rate-determining steps for the Ascaris suum nicotinamide adenine dinucleotide-malic enzyme reaction from isotope effects and pH studies

    Energy Technology Data Exchange (ETDEWEB)

    Kiick, D.M.; Harris, B.G.; Cook, P.F.

    1986-01-14

    The pH dependence of the kinetic parameters and the primary deuterium isotope effects with nicotinamide adenine dinucleotide (NAD) and also thionicotinamide adenine dinucleotide (thio-NAD) as the nucleotide substrates were determined in order to obtain information about the chemical mechanism and location of rate-determining steps for the Ascaris suum NAD-malic enzyme reaction. The maximum velocity with thio-NAD as the nucleotide is pH-independent from pH 4.2 to 9.6, while with NAD, V decreases below a pK of 4.8. V/K for both nucleotides decreases below a pK of 5.6 and above a pK of 8.9. Both the tartronate pKi and V/Kmalate decrease below a pK of 4.8 and above a pK of 8.9. Oxalate is competitive vs. malate above pH 7 and noncompetitive below pH 7 with NAD as the nucleotide. The oxalate Kis increases from a constant value above a pK of 4.9 to another constant value above a pK of 6.7. The oxalate Kii also increases above a pK of 4.9, and this inhibition is enhanced by NADH. In the presence of thio-NAD the inhibition by oxalate is competitive vs. malate below pH 7. For thio-NAD, both DV and D(V/K) are pH-independent and equal to 1.7. With NAD as the nucleotide, DV decreases to 1.0 below a pK of 4.9, while D(V/KNAD) and D(V/Kmalate) are pH-independent. Above pH 7 the isotope effects on V and the V/K values for NAD and malate are equal to 1.45, the pH-independent value of DV above pH 7. Results indicate that substrates bind to only the correctly protonated form of the enzyme. Two enzyme groups are necessary for binding of substrates and catalysis. Both NAD and malate are released from the Michaelis complex at equal rates which are equal to the rate of NADH release from E-NADH above pH 7. Below pH 7 NADH release becomes more rate-determining as the pH decreases until at pH 4.0 it completely limits the overall rate of the reaction.

  18. Protonation mechanism and location of rate-determining steps for the Ascaris suum nicotinamide adenine dinucleotide-malic enzyme reaction from isotope effects and pH studies

    International Nuclear Information System (INIS)

    Kiick, D.M.; Harris, B.G.; Cook, P.F.

    1986-01-01

    The pH dependence of the kinetic parameters and the primary deuterium isotope effects with nicotinamide adenine dinucleotide (NAD) and also thionicotinamide adenine dinucleotide (thio-NAD) as the nucleotide substrates were determined in order to obtain information about the chemical mechanism and location of rate-determining steps for the Ascaris suum NAD-malic enzyme reaction. The maximum velocity with thio-NAD as the nucleotide is pH-independent from pH 4.2 to 9.6, while with NAD, V decreases below a pK of 4.8. V/K for both nucleotides decreases below a pK of 5.6 and above a pK of 8.9. Both the tartronate pKi and V/Kmalate decrease below a pK of 4.8 and above a pK of 8.9. Oxalate is competitive vs. malate above pH 7 and noncompetitive below pH 7 with NAD as the nucleotide. The oxalate Kis increases from a constant value above a pK of 4.9 to another constant value above a pK of 6.7. The oxalate Kii also increases above a pK of 4.9, and this inhibition is enhanced by NADH. In the presence of thio-NAD the inhibition by oxalate is competitive vs. malate below pH 7. For thio-NAD, both DV and D(V/K) are pH-independent and equal to 1.7. With NAD as the nucleotide, DV decreases to 1.0 below a pK of 4.9, while D(V/KNAD) and D(V/Kmalate) are pH-independent. Above pH 7 the isotope effects on V and the V/K values for NAD and malate are equal to 1.45, the pH-independent value of DV above pH 7. Results indicate that substrates bind to only the correctly protonated form of the enzyme. Two enzyme groups are necessary for binding of substrates and catalysis. Both NAD and malate are released from the Michaelis complex at equal rates which are equal to the rate of NADH release from E-NADH above pH 7. Below pH 7 NADH release becomes more rate-determining as the pH decreases until at pH 4.0 it completely limits the overall rate of the reaction

  19. Curiosities about aldollic reaction used as a key step in the Brazilian synthesis of pteridic acids A and B; Curiosidades sobre a reacao aldolica utilizada como etapa chave na sintese brasileira dos acidos pteridicos A e B

    Energy Technology Data Exchange (ETDEWEB)

    Dias, Luiz C.; Salles Junior, Airton G. [Universidade Estadual de Campinas (UNICAMP), SP (Brazil). Inst. de Quimica

    2010-07-01

    This work describes an overview of our synthesis of pteridic acids A and B and discloses some interesting results related to the lithium enolate-mediated aldol reaction used as key step to set up the C5-C15 fragment of these natural products. This first example, as far we know, of an aldol reaction between a chiral enolate of a (Z) enone and a chiral aldehyde has driven us to a series of experiments showing the remarkable relation between enolization selectivity and reaction conditions. (author)

  20. One-Step Fabrication of Monolithic Electrodes Comprising Co9S8Particles Supported on Cobalt Foam for Efficient and Durable Oxygen Evolution Reaction.

    Science.gov (United States)

    Xiong, Dehua; Zhang, Qingqing; Thalluri, Sitaramanjaneya Mouli; Xu, Junyuan; Li, Wei; Fu, Xiuli; Liu, Lifeng

    2017-06-27

    A very easy and cost-effective approach to the fabrication of monolithic Co 9 S 8 water oxidation electrodes (Co@Co 9 S 8 ), fabricated by one-step hydrothermal treatment of commercially available cobalt foam in the presence of thiourea, is reported. The morphology, crystal structure, microstructure, and composition of as-fabricated Co@Co 9 S 8 electrodes were examined by using scanning electron microscopy (SEM), powder X-ray diffractometry (XRD), transmission electron microscope (TEM), and X-ray photoelectron spectroscopy (XPS), and their electrochemical properties were investigated by cyclic voltammetry (CV), chronopotentiometry (CP), chronoamperometry (CA), and electrochemical impedance spectroscopy (EIS). When used to catalyze the oxygen evolution reaction (OER) in alkaline solution, the Co@Co 9 S 8 electrode with an optimal Co 9 S 8 loading exhibits outstanding catalytic activity, requiring a low overpotential of 350 mV to deliver an anodic current density of 10 mA cm -2 and showing fast kinetics for OER with a small Tafel slope (55 mV dec -1 ) and charge-transfer resistance (0.44 Ω cm -2 ), which outperforms many sulfide-based OER catalysts and some state-of-the-art noble metal catalysts recently reported in the literature. Importantly, the electrodes show excellent long-term stability, and are capable of operating at both a low current density and a high current density relevant to industrial water electrolysis up to 100 hours. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  1. The Nine-Step Minnesota Grading System for Eyebank Eyes With Age Related Macular Degeneration: A Systematic Approach to Study Disease Stages.

    Science.gov (United States)

    Olsen, Timothy W; Liao, Albert; Robinson, Hershonna S; Palejwala, Neal V; Sprehe, Nicholas

    2017-10-01

    To refine the Minnesota Grading System (MGS) using definitions from the Age-Related Eye Disease Studies (AREDS) into a nine-step grading scale (MGS-9). A nine-step grading scale descriptive analysis using three key phenotypic features (total drusen area, increased, and decreased pigmentation) of human eyebank eyes that were graded according to definitions from the AREDS criteria in order to harmonize studies of disease progression for research involving human tissue. From 2005 through February 2017, we have analyzed 1159 human eyes, procured from two eyebanks. Each macula was imaged using high-resolution, stereoscopic color fundus photography with both direct- and transillumination. Fundus images were digitally overlaid with a grading template and triangulated for foveal centration. We documented and stratified risk for each globe by applying the AREDS nine-step grading scale to the key clinical features from the MGS-9. We found a good distribution within the MGS categories (1-9) with few level eight globes. Eyes were processed within 12.1 ± 6.3, hours from the time of death through imaging, dissection, and freezing or fixation. Applying the MGS-9 to 331 pairs (662 eyes were simultaneously graded), 84% were within one-grading step and 93% within two steps of the fellow eye. We also document reticular pseudodrusen, basal laminar drusen, and pattern dystrophy. The MGS nine-step grading scale enables researchers using human tissue to refine the risk assessment of donor tissue. This analysis will harmonize results among researchers when grading human tissue using MGS criteria. Most importantly, the MGS-9 links directly to the known risk for progression from the AREDS.

  2. A further step toward H2 in automobile : development of an efficient bi-functional catalyst for single stage water gas shift

    NARCIS (Netherlands)

    Azzam, K.G.H.

    2008-01-01

    The suitability of polymer electrolyte fuel (PEM) cells for stationary and vehicular applications initiated research in all areas of fuel processor (i.e. reformer, water-gas-shift, preferential oxidation of CO (PROX)) catalysts for hydrogen generation. Water gas shift (WGS) reaction is an essential

  3. Some Calculated (p,α Cross-Sections Using the Alpha Particle Knock-On and Triton Pick-Up Reaction Mechanisms: An Optimisation of the Single-Step Feshbach–Kerman–Koonin (FKK Theory

    Directory of Open Access Journals (Sweden)

    Felix S. Olise

    2016-04-01

    Full Text Available The Feshbach–Kerman–Koonin (FKK multi-step direct (MSD theory of pre-equilibrium reactions has been used to compute the single-step cross-sections for some (p,α reactions using the knock-on and pick-up reaction mechanisms at two incident proton energies. For the knock-on mechanism, the reaction was assumed to have taken place by the direct ejection of a preformed alpha cluster in a shell-model state of the target. But the reaction was assumed to have taken place by the pick-up of a preformed triton cluster (also bound in a shell-model state of the target core by the incident proton for the pick-up mechanism. The Yukawa forms of potential were used for the proton-alpha (for the knock-on process and proton-triton (for the pick-up process interaction and several parameter sets for the proton and alpha-particle optical potentials. The calculated cross-sections for both mechanisms gave satisfactory fits to the experimental data. Furthermore, it has been shown that some combinations of the calculated distorted wave Born approximation cross-sections for the two reaction mechanisms in the FKK MSD theory are able to give better fits to the experimental data, especially in terms of range of agreement. In addition, the theory has been observed to be valid over a wider range of energy.

  4. In-beam γ-ray spectroscopy of two-step fragmentation reactions at relativistic energies. The case of 36Ca

    International Nuclear Information System (INIS)

    Doornenbal, P.

    2007-01-01

    A two-step fragmentation experiment has been performed at GSI with the RISING setup. It combines the fragment separator FRS, which allows for the production of radioactive heavy ions at relativistic energies, with a high resolution γ-spectrometer. This combination offers unique possibilities for nuclear structure investigations like the test of shell model predictions far from stability. Within the present work the question if the N=14(16) shell stabilisation in Z=8 oxygen isotopes and the N=20 shell quenching in 32 Mg are symmetric with respect to the isospin projection quantum number Tz has been addressed. New γ-ray decays were found in the neutron deficient 36 Ca and 36 K by impinging a radioactive ion beam of 37 Ca on a secondary 9 Be target. The fragmentation products were selected with the calorimeter telescope CATE and the emitted γ-rays were measured with Ge Cluster, MINIBALL, and BaF 2 HECTOR detectors. For 36 Ca the 2 1 + →0 g.s. + transition energy was determined to be 3015(16) keV, which is the heaviest T=2 nucleus from which γ-spectroscopic information has been obtained so far. A comparison between the experimental 2 1 + energies of 36 Ca and its mirror nucleus 36 S yielded a mirror energy difference of ΔE M =-276(16) keV. In order to understand the large ΔE M value, the experimental single-particle energies from the A=17, T=1/2 mirror nuclei were taken and applied onto modified isospin symmetric USD interactions in shell model calculations. These calculations were in agreement with the experimental result and showed that the experimental single-particle energies may account empirically for the one body part of Thomas-Ehrman and/or Coulomb effects. A method to extract the lifetime of excited states in fragmentation reactions was investigated. Therefore, the dependence between the lifetime of an excited state and the average de-excitation velocity and trajectory of the nuclei in relativistic fragmentation experiments has been studied. Known

  5. In-beam {gamma}-ray spectroscopy of two-step fragmentation reactions at relativistic energies. The case of {sup 36}Ca

    Energy Technology Data Exchange (ETDEWEB)

    Doornenbal, P.

    2007-10-23

    A two-step fragmentation experiment has been performed at GSI with the RISING setup. It combines the fragment separator FRS, which allows for the production of radioactive heavy ions at relativistic energies, with a high resolution {gamma}-spectrometer. This combination offers unique possibilities for nuclear structure investigations like the test of shell model predictions far from stability. Within the present work the question if the N=14(16) shell stabilisation in Z=8 oxygen isotopes and the N=20 shell quenching in {sup 32}Mg are symmetric with respect to the isospin projection quantum number Tz has been addressed. New {gamma}-ray decays were found in the neutron deficient {sup 36}Ca and {sup 36}K by impinging a radioactive ion beam of {sup 37}Ca on a secondary {sup 9}Be target. The fragmentation products were selected with the calorimeter telescope CATE and the emitted {gamma}-rays were measured with Ge Cluster, MINIBALL, and BaF{sub 2} HECTOR detectors. For {sup 36}Ca the 2{sub 1}{sup +}{yields}0{sub g.s.}{sup +} transition energy was determined to be 3015(16) keV, which is the heaviest T=2 nucleus from which {gamma}-spectroscopic information has been obtained so far. A comparison between the experimental 2{sub 1}{sup +} energies of {sup 36}Ca and its mirror nucleus {sup 36}S yielded a mirror energy difference of {delta}E{sub M}=-276(16) keV. In order to understand the large {delta}E{sub M} value, the experimental single-particle energies from the A=17, T=1/2 mirror nuclei were taken and applied onto modified isospin symmetric USD interactions in shell model calculations. These calculations were in agreement with the experimental result and showed that the experimental single-particle energies may account empirically for the one body part of Thomas-Ehrman and/or Coulomb effects. A method to extract the lifetime of excited states in fragmentation reactions was investigated. Therefore, the dependence between the lifetime of an excited state and the average de

  6. One-step simultaneous differential scanning calorimetry-FTIR microspectroscopy to quickly detect continuous pathways in the solid-state glucose/asparagine Maillard reaction.

    Science.gov (United States)

    Hwang, Deng-Fwu; Hsieh, Tzu-Feng; Lin, Shan-Yang

    2013-01-01

    The stepwise reaction pathway of the solid-state Maillard reaction between glucose (Glc) and asparagine (Asn) was investigated using simultaneous differential scanning calorimetry (DSC)-FTIR microspectroscopy. The color change and FTIR spectra of Glc-Asn physical mixtures (molar ratio = 1:1) preheated to different temperatures followed by cooling were also examined. The successive reaction products such as Schiff base intermediate, Amadori product, and decarboxylated Amadori product in the solid-state Glc-Asn Maillard reaction were first simultaneously evidenced by this unique DSC-FTIR microspectroscopy. The color changed from white to yellow-brown to dark brown, and appearance of new IR peaks confirmed the formation of Maillard reaction products. The present study clearly indicates that this unique DSC-FTIR technique not only accelerates but also detects precursors and products of the Maillard reaction in real time.

  7. Next Step for STEP

    Energy Technology Data Exchange (ETDEWEB)

    Wood, Claire [CTSI; Bremner, Brenda [CTSI

    2013-08-09

    The Siletz Tribal Energy Program (STEP), housed in the Tribe’s Planning Department, will hire a data entry coordinator to collect, enter, analyze and store all the current and future energy efficiency and renewable energy data pertaining to administrative structures the tribe owns and operates and for homes in which tribal members live. The proposed data entry coordinator will conduct an energy options analysis in collaboration with the rest of the Siletz Tribal Energy Program and Planning Department staff. An energy options analysis will result in a thorough understanding of tribal energy resources and consumption, if energy efficiency and conservation measures being implemented are having the desired effect, analysis of tribal energy loads (current and future energy consumption), and evaluation of local and commercial energy supply options. A literature search will also be conducted. In order to educate additional tribal members about renewable energy, we will send four tribal members to be trained to install and maintain solar panels, solar hot water heaters, wind turbines and/or micro-hydro.

  8. ReactionPredictor: prediction of complex chemical reactions at the mechanistic level using machine learning.

    Science.gov (United States)

    Kayala, Matthew A; Baldi, Pierre

    2012-10-22

    Proposing reasonable mechanisms and predicting the course of chemical reactions is important to the practice of organic chemistry. Approaches to reaction prediction have historically used obfuscating representations and manually encoded patterns or rules. Here we present ReactionPredictor, a machine learning approach to reaction prediction that models elementary, mechanistic reactions as interactions between approximate molecular orbitals (MOs). A training data set of productive reactions known to occur at reasonable rates and yields and verified by inclusion in the literature or textbooks is derived from an existing rule-based system and expanded upon with manual curation from graduate level textbooks. Using this training data set of complex polar, hypervalent, radical, and pericyclic reactions, a two-stage machine learning prediction framework is trained and validated. In the first stage, filtering models trained at the level of individual MOs are used to reduce the space of possible reactions to consider. In the second stage, ranking models over the filtered space of possible reactions are used to order the reactions such that the productive reactions are the top ranked. The resulting model, ReactionPredictor, perfectly ranks polar reactions 78.1% of the time and recovers all productive reactions 95.7% of the time when allowing for small numbers of errors. Pericyclic and radical reactions are perfectly ranked 85.8% and 77.0% of the time, respectively, rising to >93% recovery for both reaction types with a small number of allowed errors. Decisions about which of the polar, pericyclic, or radical reaction type ranking models to use can be made with >99% accuracy. Finally, for multistep reaction pathways, we implement the first mechanistic pathway predictor using constrained tree-search to discover a set of reasonable mechanistic steps from given reactants to given products. Webserver implementations of both the single step and pathway versions of Reaction

  9. Systematic staging design applied to the fixed-bed reactor series for methanol and one-step methanol/dimethyl ether synthesis

    International Nuclear Information System (INIS)

    Manenti, Flavio; Leon-Garzon, Andres R.; Ravaghi-Ardebili, Zohreh; Pirola, Carlo

    2014-01-01

    This work investigates possible design advances in the series of fixed-bed reactors for methanol and dimethyl ether synthesis. Specifically, the systematic staging design proposed by Hillestad [1] is applied to the water-cooled and gas-cooled series of reactors of Lurgi's technology. The procedure leads to new design and operating conditions with respect to the current best industrial practice, with relevant benefits in terms of process yield, energy saving, and net income. The overall mathematical model for the process simulation and optimization is reported in the work together with dedicated sensitivity analysis studies. - Highlights: • Systematic staging design is applied to methanol and methanol/DME synthesis. • New configurations for the synthesis reactor network are proposed and assessed. • Comparison with the industrial best practice is provided. • Energy-process optimization is performed to improve the overall yield of the process

  10. Treatment influencing down-staging in EORTC Melanoma Group sentinel node histological protocol compared with complete step-sectioning: a national multicentre study.

    Science.gov (United States)

    Riber-Hansen, Rikke; Hastrup, Nina; Clemmensen, Ole; Behrendt, Nille; Klausen, Siri; Ramsing, Mette; Spaun, Eva; Hamilton-Dutoit, Stephen Jacques; Steiniche, Torben

    2012-02-01

    Metastasis size in melanoma sentinel lymph nodes (SLNs) is an emerging prognostic factor. Two European melanoma treatment trials include SLN metastasis diameters as inclusion criteria. Whilst diameter estimates are sensitive to the number of sections examined, the level of this bias is largely unknown. We performed a prospective multicentre study to compare the European Organisation for Research and Treatment of Cancer (EORTC) recommended protocol with a protocol of complete step-sectioning. One hundred and thirty-three consecutive SLNs from seven SLN centres were analysed by five central sections 50μm apart (EORTC Protocol) followed by complete 250μm step-sectioning. Overall, 29 patients (21.8%) were SLN-positive. The EORTC Protocol missed eight of these metastases (28%), one metastasis measuring less than 0.1mm in diameter, seven measuring between 0.1 and 1mm. Complete step-sectioning at 250μm intervals (Extensive Protocol) missed one metastasis (3%) that measured less than 0.1mm. Thirteen treatment courses (34%) performed if inclusion was based on the Combined Protocol would not be performed if assessed by the EORTC Protocol. Thus, 10 patients would be without completion lymph node dissection (EORTC MINITUB study), whilst three patients would not be eligible for anti-CTLA4 trial (EORTC protocol 18071). The corresponding number with the Extensive Protocol would be three; one patient for the MINITUB registration study and two patients for the anti-CTLA4 study. Examining SLNs by close central sectioning alone (EORTC Protocol) misses a substantial number of metastases and underestimates the maximum metastasis diameter, leading to important changes in patient eligibility for various treatment protocols. Copyright © 2011 Elsevier Ltd. All rights reserved.

  11. Step sites in syngas catalysis

    DEFF Research Database (Denmark)

    Rostrup-Nielsen, J.; Nørskov, Jens Kehlet

    2006-01-01

    Step sites play an important role in many catalytic reactions. This paper reviews recent results on metal catalysts for syngas reactions with emphasis on steam reforming. Modern characterization techniques (STEM, HREM...) and theoretical calculations (DFT) has allowed a more quantitative...

  12. Sublobar resection versus lobectomy in Surgical Treatment of Elderly Patients with early-stage non-small cell lung cancer (STEPS): study protocol for a randomized controlled trial.

    Science.gov (United States)

    Yang, Fan; Sui, Xizhao; Chen, Xiuyuan; Zhang, Lixue; Wang, Xun; Wang, Shaodong; Wang, Jun

    2016-04-07

    The appropriateness of lobectomy for all elderly patients is controversial. Meanwhile, sublobar resection is associated with reduced operative risk, better preservation of pulmonary function, and a better quality of life, constituting a potential alternative to standard lobectomy for elderly patients with early-stage non-small cell lung cancer (NSCLC). To date, no randomized trial comparing sublobar resection and lobectomy focusing on elderly patients has been reported. We hypothesized that for patients at least 70 years old with clinical stage T1N0M0 NSCLC, sublobar resection is non-inferior to lobectomy for 3-year disease-free survival (DFS). This is a prospective, randomized, controlled multicenter non-inferiority trial with two study arms: sublobar resection and lobectomy groups. Comprehensive geriatric assessments will be acquired for each patient. A total of 339 subjects will be enrolled on the basis of power calculations, and participants followed up every 6 months post-operation for 3 years. In case of relapse, survival follow-up will be continued until 5 years or death. Pulmonary function testing will be performed at 6, 12, and 36 months post-operation. The primary outcome is 3-year DFS; secondary endpoints include peri-operative complications and mortality, hospitalization time, post-operative ventilator time, overall survival, 3-year recurrence rates, post-operative pulmonary function, quality of life, geriatric assessment data, and 4-year mortality index. The present study is the only prospective, multicenter, randomized controlled trial comparing sublobar resection and lobectomy for elderly patients. The therapeutic outcomes of sublobar resection will be evaluated in comparison with lobectomy for elderly patients (≥70 years) with early-stage NSCLC. NCT02360761 : 01/24/2015 (ClinicalTrials.gov).

  13. Design and synthesis of hybrid cyclophanes containing thiophene and indole units via Grignard reaction, Fischer indolization and ring-closing metathesis as key steps

    Directory of Open Access Journals (Sweden)

    Sambasivarao Kotha

    2015-08-01

    Full Text Available We demonstrate a new synthetic strategy to cyclophanes containing thiophene and indole moieties via Grignard addition, Fischer indolization and ring-closing metathesis as key steps.

  14. Enhanced Sensitivity for Selected Reaction Monitoring Mass Spectrometry-based Targeted Proteomics Using a Dual Stage Electrodynamic Ion Funnel Interface*

    Science.gov (United States)

    Hossain, Mahmud; Kaleta, David T.; Robinson, Errol W.; Liu, Tao; Zhao, Rui; Page, Jason S.; Kelly, Ryan T.; Moore, Ronald J.; Tang, Keqi; Camp, David G.; Qian, Wei-Jun; Smith, Richard D.

    2011-01-01

    Selected reaction monitoring mass spectrometry (SRM-MS) is playing an increasing role in quantitative proteomics and biomarker discovery studies as a method for high throughput candidate quantification and verification. Although SRM-MS offers advantages in sensitivity and quantification compared with other MS-based techniques, current SRM technologies are still challenged by detection and quantification of low abundance proteins (e.g. present at ∼10 ng/ml or lower levels in blood plasma). Here we report enhanced detection sensitivity and reproducibility for SRM-based targeted proteomics by coupling a nanospray ionization multicapillary inlet/dual electrodynamic ion funnel interface to a commercial triple quadrupole mass spectrometer. Because of the increased efficiency in ion transmission, significant enhancements in overall signal intensities and improved limits of detection were observed with the new interface compared with the original interface for SRM measurements of tryptic peptides from proteins spiked into non-depleted mouse plasma over a range of concentrations. Overall, average SRM peak intensities were increased by ∼70-fold. The average level of detection for peptides also improved by ∼10-fold with notably improved reproducibility of peptide measurements as indicated by the reduced coefficients of variance. The ability to detect proteins ranging from 40 to 80 ng/ml within mouse plasma was demonstrated for all spiked proteins without the application of front-end immunoaffinity depletion and fractionation. This significant improvement in detection sensitivity for low abundance proteins in complex matrices is expected to enhance a broad range of SRM-MS applications including targeted protein and metabolite validation. PMID:20410378

  15. Use of the Spin-Trapping method to establish the radical steps in the reactions of organic compounds of zinc, cadmium, and mercury with various peroxides

    International Nuclear Information System (INIS)

    Dodonov, V.A.; Grishin, D.F.

    1985-01-01

    This paper uses the spin trapping method to investigate the homolytic reactions of group II organometallic compounds (OMC) with organic and heteroorganic peroxides. The radical reactions of the OMC with peroxides was investigated and the reactivity of the spin traps was examined with respect to compounds of zinc, cadmium, and mercury. Phenyl-tert-butylnitron (I), 2-methyl-2-nitrosopropane (II), and tri-bromonitrobenzene (III) were chosen as spin traps. The radicals formed are aable to initiate the polymerization of vinyl monomers

  16. Highly functionalized and potent antiviral cyclopentane derivatives formed by a tandem process consisting of organometallic, transition-metal-catalyzed, and radical reaction steps.

    Science.gov (United States)

    Jagtap, Pratap R; Ford, Leigh; Deister, Elmar; Pohl, Radek; Císařová, Ivana; Hodek, Jan; Weber, Jan; Mackman, Richard; Bahador, Gina; Jahn, Ullrich

    2014-08-11

    A simple modular tandem approach to multiply substituted cyclopentane derivatives is reported, which succeeds by joining organometallic addition, conjugate addition, radical cyclization, and oxygenation steps. The key steps enabling this tandem process are the thus far rarely used isomerization of allylic alkoxides to enolates and single-electron transfer to merge the organometallic step with the radical and oxygenation chemistry. This controlled lineup of multiple electronically contrasting reactive intermediates provides versatile access to highly functionalized cyclopentane derivatives from very simple and readily available commodity precursors. The antiviral activity of the synthesized compounds was screened and a number of compounds showed potent activity against hepatitis C and dengue viruses. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. Investigation to biodiesel production by the two-step homogeneous base-catalyzed transesterification.

    Science.gov (United States)

    Ye, Jianchu; Tu, Song; Sha, Yong

    2010-10-01

    For the two-step transesterification biodiesel production made from the sunflower oil, based on the kinetics model of the homogeneous base-catalyzed transesterification and the liquid-liquid phase equilibrium of the transesterification product, the total methanol/oil mole ratio, the total reaction time, and the split ratios of methanol and reaction time between the two reactors in the stage of the two-step reaction are determined quantitatively. In consideration of the transesterification intermediate product, both the traditional distillation separation process and the improved separation process of the two-step reaction product are investigated in detail by means of the rigorous process simulation. In comparison with the traditional distillation process, the improved separation process of the two-step reaction product has distinct advantage in the energy duty and equipment requirement due to replacement of the costly methanol-biodiesel distillation column. Copyright 2010 Elsevier Ltd. All rights reserved.

  18. Atomic resolution structures of discrete stages on the reaction coordinate of the [Fe4S4] enzyme IspG (GcpE)

    KAUST Repository

    Quitterer, Felix

    2015-04-11

    IspG is the penultimate enzyme in non-mevalonate biosynthesis of the universal terpene building blocks isopentenyl diphosphate and dimethylallyl diphosphate. Its mechanism of action has been the subject of numerous studies but remained unresolved due to difficulties in identifying distinct reaction intermediates. Using a moderate reducing agent as well as an epoxide substrate analogue, we were now able to trap and crystallographically characterize various stages in the IspG catalyzed conversion of 2-C-methyl-D-erythritol-2,4-cyclo-diphosphate (MEcPP) to (E)-1-hydroxy-2-methylbut-2-enyl-4-diphosphate (HMBPP). In addition, the enzyme’s structure was determined in complex with several inhibitors. These results, combined with recent electron paramagnetic resonance data, allowed us to deduce a detailed and complete IspG catalytic mechanism which describes all stages from initial ring opening to formation of HMBPP via discrete radical and carbanion intermediates. The data presented in this article provide a guide for the design of selective drugs against many pro- and eukaryotic pathogens to which the non-mevalonate pathway is essential for survival and virulence.

  19. PVDF-HFP/silica-SH nanocomposite synthesis for PEMFC membranes through simultaneous one-step sol–gel reaction and reactive extrusion

    International Nuclear Information System (INIS)

    Seck, S.; Magana, S.; Prébé, A.; Niepceron, F.

    2015-01-01

    In this study, synthesis of thiol-functionalized silica/PVDF-HFP [poly(vinylidene fluoride-hexafluoropropylene)] nanocomposite materials was carried out by reactive extrusion through in situ sol–gel reactions of an alkoxysilane inorganic precursor solution composed of polydimethoxysiloxane (PDMOS) and mercaptopropyltriethoxysilane (MPTES). Successful introduction of the functional MPTES and structural PDMOS alkoxysilanes, and subsequent condensation reactions in the PVDF-HFP, were obtained through pre-hydrolysis reactions of the precursors. 29 Si-Nuclear magnetic resonance was used to assess the hydrolysis level of the inorganic precursor solution and condensation state in the resulting PVDF-HFP/functionalized silica nanocomposites, while the morphology was observed using scanning electron microscopy (SEM). The hydrolysis-condensation reactions resulting in the inorganic phase were optimized by setting an appropriate R 0 molar ratio (H 2 O/alkoxy function), R 1 molar ratio (MPTES/PDMOS) and pH of the solution. Increasing the R 0 ratio barely affected the hydrolysis kinetics. However, a higher R 1 ratio led to a decrease in the inorganic precursors condensation state and consequently to an increase in the reaction time in the extruder to reach the subsequent condensation state. Hence the morphology of the obtained nanocomposites was finer for the highest R 1 ratio and in agreement with the evolution of the solubility parameters. Promising ionic exchange capacity (IEC) and conductivity values were obtained for these innovative nanocomposite materials thanks to a controlled oxidation reaction of the thiol groups into sulfonic acid functions. This original approach demonstrated the possibility of incorporating in situ functionalized silica into a molten fluorinated polymer matrix in a unique reactive extrusion procedure. - Highlights: • Thiol-functionalized silica/PVDF-HFP nanocomposite synthesis by sol–gel and extrusion. • Promising IEC (0.7 meq g −1 ) and

  20. The Importance of Teachers' Feelings of Self Efficacy in Developing Their Pupils' Social and Emotional Learning: A Norwegian Study of Teachers' Reactions to the Second Step Program

    Science.gov (United States)

    Larsen, Torill; Samdal, Oddrun

    2012-01-01

    The aim of this study was to explore teachers' (n = 17) experience with the Second Step program (1986) as a tool for teaching social competence through semi-structured interviews. Findings suggest that use of the program had a positive influence on the teachers' overall teaching techniques and their broader social behaviour. The majority of the…

  1. PVDF-HFP/silica-SH nanocomposite synthesis for PEMFC membranes through simultaneous one-step sol–gel reaction and reactive extrusion

    Energy Technology Data Exchange (ETDEWEB)

    Seck, S. [Université de Lyon, Université Lyon 1, UMR CNRS 5223 Ingénierie des Matériaux Polymères, IMP@Lyon1, Bât PolyTech, 15 Boulevard Latarjet, 69622 Villeurbanne Cedex (France); Université de Lyon, INSA, UMR CNRS 5223 Ingénierie des Matériaux Polymères IMP@INSA, Batîment Jules Verne, 17 avenue Jean Capelle, 69621 Villeurbanne Cedex (France); Magana, S. [Université de Lyon, Université Lyon 1, UMR CNRS 5223 Ingénierie des Matériaux Polymères, IMP@Lyon1, Bât PolyTech, 15 Boulevard Latarjet, 69622 Villeurbanne Cedex (France); Prébé, A.; Niepceron, F. [Université de Lyon, Université Lyon 1, UMR CNRS 5223 Ingénierie des Matériaux Polymères, IMP@Lyon1, Bât PolyTech, 15 Boulevard Latarjet, 69622 Villeurbanne Cedex (France); Université de Lyon, INSA, UMR CNRS 5223 Ingénierie des Matériaux Polymères IMP@INSA, Batîment Jules Verne, 17 avenue Jean Capelle, 69621 Villeurbanne Cedex (France); and others

    2015-08-01

    In this study, synthesis of thiol-functionalized silica/PVDF-HFP [poly(vinylidene fluoride-hexafluoropropylene)] nanocomposite materials was carried out by reactive extrusion through in situ sol–gel reactions of an alkoxysilane inorganic precursor solution composed of polydimethoxysiloxane (PDMOS) and mercaptopropyltriethoxysilane (MPTES). Successful introduction of the functional MPTES and structural PDMOS alkoxysilanes, and subsequent condensation reactions in the PVDF-HFP, were obtained through pre-hydrolysis reactions of the precursors. {sup 29}Si-Nuclear magnetic resonance was used to assess the hydrolysis level of the inorganic precursor solution and condensation state in the resulting PVDF-HFP/functionalized silica nanocomposites, while the morphology was observed using scanning electron microscopy (SEM). The hydrolysis-condensation reactions resulting in the inorganic phase were optimized by setting an appropriate R{sub 0} molar ratio (H{sub 2}O/alkoxy function), R{sub 1} molar ratio (MPTES/PDMOS) and pH of the solution. Increasing the R{sub 0} ratio barely affected the hydrolysis kinetics. However, a higher R{sub 1} ratio led to a decrease in the inorganic precursors condensation state and consequently to an increase in the reaction time in the extruder to reach the subsequent condensation state. Hence the morphology of the obtained nanocomposites was finer for the highest R{sub 1} ratio and in agreement with the evolution of the solubility parameters. Promising ionic exchange capacity (IEC) and conductivity values were obtained for these innovative nanocomposite materials thanks to a controlled oxidation reaction of the thiol groups into sulfonic acid functions. This original approach demonstrated the possibility of incorporating in situ functionalized silica into a molten fluorinated polymer matrix in a unique reactive extrusion procedure. - Highlights: • Thiol-functionalized silica/PVDF-HFP nanocomposite synthesis by sol–gel and extrusion.

  2. Single step synthesis of gold-amino acid composite, with the evidence of the catalytic hydrogen atom transfer (HAT) reaction, for the electrochemical recognition of Serotonin

    Science.gov (United States)

    Choudhary, Meenakshi; Siwal, Samarjeet; Nandi, Debkumar; Mallick, Kaushik

    2016-03-01

    A composite architecture of amino acid and gold nanoparticles has been synthesized using a generic route of 'in-situ polymerization and composite formation (IPCF)' [1,2]. The formation mechanism of the composite has been supported by a model hydrogen atom (H•≡H++e-) transfer (HAT) type of reaction which belongs to the proton coupled electron transfer (PCET) mechanism. The 'gold-amino acid composite' was used as a catalyst for the electrochemical recognition of Serotonin.

  3. One-step synthesis of metal@titania core-shell materials for visible-light photocatalysis and catalytic reduction reaction.

    Science.gov (United States)

    Xiong, Zhigang; Zhang, Luhong; Zhao, Xiu Song

    2014-11-03

    Metal@TiO2 composites with a core-shell structure possess multifunctional properties. The demonstrated protocols for synthesizing such materials involve multiple steps, requiring precise control over the particle uniformity of the core and shell thickness, as well as complex surface modification. A simple approach to synthesizing metal@TiO2 hybrid nanostructures remains a great challenge. Herein, we report on a one-step method for the preparation of metal@TiO2 core-shell nanospheres, which exhibited excellent performance in photocatalytic degradation of recalcitrant organic pollutants under visible light irradiation, and in catalytic reduction of nitrophenol in water. The simple method described here represents a sustainable approach to preparing core-shell materials at low cost, involving fewer chemicals, and requiring less energy, which will make a significant contribution toward large-scale synthesis of high-performance hybrid materials for photocatalytic applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  4. One-step preparation of carbon nanotubes doped mesoporous birnessite K2Mn4O9 achieving 77% of theoretical capacitance by a facile redox reaction

    Science.gov (United States)

    Kang, Litao; Li, Peiyang; Tao, Keyu; Wang, Xiaomin; Liang, Wei; Gao, Yanfeng

    2016-01-01

    A facile, scalable and cost-efficient redox reaction is developed to prepare micro-powders of a quasi-crystallised, mesoporous birnessite-type manganese oxide, K2Mn4O9. In 1 M KOH electrolyte, the K2Mn4O9 powder shows a high specific capacitance of 754 F g-1 at 1 A g-1 (calculated with the net weight of K2Mn4O9 micro-powder only). Meanwhile, the electrode retains 91% of its initial capacitance after 5000 cycles at a high current density of 5 A g-1. By simply adding carbon nanotubes (CNTs) into the reaction system, the specific capacitances of as-prepared K2Mn4O9/CNTs composites are further increased to 929 and 1055 F g-1 at 1 A g-1 in 1 and 6 M KOH electrolyte (corresponding to 69 and 77% of the theoretical capacitance of MnO2), or 600 and 674 F g-1 at 5 A g-1, respectively. Significantly, a maximum energy density of 62 Wh kg-1 at a power density of 852 W kg-1 could be achieved based on a K2Mn4O9/CNTs//activated carbon asymmetric supercapacitor (ASC). At the same time, the ASC device exhibits a decent long cycle life with 85% specific capacitance retained after 1000 cycles, suggesting its wide application potential in low-cost high energy density storage systems.

  5. One-Step Hydrothermal Fabrication of Three-dimensional MoS2 Nanoflower using Polypyrrole as Template for Efficient Hydrogen Evolution Reaction.

    Science.gov (United States)

    Lu, Xin; Lin, Yingwu; Dong, Haifeng; Dai, Wenhao; Chen, Xin; Qu, Xuanhui; Zhang, Xueji

    2017-02-14

    Herein, a facile and cost-effective strategy for hydrothermal synthesis of three-dimensional (3D) MoS 2 with adequate active edge sites and advanced hydrogen evolution reaction (HER) performance using polypyrrole (PPy) as template is reported. The MoS 2 is first thermally nucleated using hexaammonium heptamolybdate tetrahydrate (NH 4 ) 6 Mo 7 O 24 ·4H 2 O and thiourea as precursor in the presence of PPy, and then they are further annealed to remove PPy at higher temperature to generate 3D MoS 2 -P. Morphology and composition characterizations reveal that the 3D MoS 2 -P exhibits a nanoflower morphology. It presents larger stretched "thin folding leaves" and higher mesoporous volume of 0.608 cm 3 g -1 than the MoS 2 without PPy as template. Importantly, the 3D MoS 2 -P shows enhanced HER catalytic activity (onset potential at -100 mV) than previously reports that MoS 2 -based HER catalysts. The large "thin folding leaves" possessing efficient edge active sites and defects are responsible to for the enhanced HER performance, while the high mesoporous volume facilitates the transfer of reaction substrate. Our study provides a facile and cost-effective method for synthesis of 3D MoS 2 with advanced HER performances, which has great potential for larger-scale production and practical industrial applications.

  6. Economic evaluation of 21-gene reverse transcriptase-polymerase chain reaction assay in lymph-node-negative, estrogen-receptor-positive, early-stage breast cancer in Japan.

    Science.gov (United States)

    Kondo, Masahide; Hoshi, Shu Ling; Ishiguro, Hiroshi; Yoshibayashi, Hiroshi; Toi, Masakazu

    2008-11-01

    The 21-gene reverse transcriptase-polymerase chain reaction assay with a patented algorithm is validated as a good predictor of prognosis and potential benefit from adjuvant chemotherapy for lymph-node-negative, estrogen-receptor-positive, early-stage breast cancer, while its high cost raises concern about how to finance it. Cost-effectiveness analysis comparing prevalent National Comprehensive Cancer Network (NCCN) guideline/St Gallen recommendation-guided treatment with the assay-guided treatment is carried out with budget impact estimation in the context of Japan's health care system. Incremental cost-effectiveness ratios are estimated as 2,997,495 yen/QALY (26,065 US$/QALY) in the comparison between NCCN guided-treatment vs. the assay-guided treatment, and as 1,239,055 yen/QALY (10,774 US$/QALY) in the comparison between St Gallen guided-treatment vs. the assay-guided treatment. Budget impact is estimated as yen2,638 million (US$23 million) to yen3,225 million (US$28 million) per year. The routine use of the assay is indicated as cost-effective. And the budget impact could be judged as within fundable level.

  7. Optimization of one-step real-time reverse transcription-polymerase chain reaction assays for norovirus detection and molecular epidemiology of noroviruses in Thailand.

    Science.gov (United States)

    Neesanant, Pimmnapar; Sirinarumitr, Theerapol; Chantakru, Siriruk; Boonyaprakob, Ukadaj; Chuwongkomon, Kaittawee; Bodhidatta, Ladaporn; Sethabutr, Orntipa; Abente, Eugenio J; Supawat, Krongkaew; Mason, Carl J

    2013-12-01

    Noroviruses (NoVs) are an important human pathogen associated with acute viral gastroenteritis worldwide. NoVs display a significant amount of genetic heterogeneity, making it difficult to develop comprehensive detection assays. In this study, primer sets and probes were designed for a TaqMan(®)-based real-time reverse transcription-polymerase chain reaction (RT-PCR) for norovirus detection purposes. The assay was optimized and utilized as a multiplex real-time RT-PCR assay for genogroup I (GI) detection, and a singleplex real-time RT-PCR assay for genogroup II (GII) detection. The assays showed high specificity for NoV detection and no cross-reactivity was observed between GI and GII. The detection limit of the assay was as low as 10 and 50 RNA copies per reaction for GI and GII, respectively. The optimized protocol was employed to assess the presence of NoV strains in clinical samples collected throughout Thailand during December 2005 to November 2006. The percentage of NoV infections among children with acute gastroenteritis (case) was 23.8% (119/500) and for children without acute gastroenteritis (control) it was 6.8% (30/441). The frequency of NoV infections varied geographically, with the highest frequency observed in the central region and the lowest frequency in the northern region (P>0.0001). Of the 149 positive case and control specimens, GII was found to be the predominant genogroup (98.6%). Partial capsid sequences were successfully obtained from 67 NoV-positive specimens and a phylogenetic analysis was performed to genotype the viral strains. GII.4 was the most common genotype detected. Copyright © 2013 The Authors. Published by Elsevier B.V. All rights reserved.

  8. Highly efficient pulsed power supply system with a two-stage LC generator and a step-up transformer for fast capillary discharge soft x-ray laser at shorter wavelength.

    Science.gov (United States)

    Sakai, Yusuke; Takahashi, Shnsuke; Komatsu, Takanori; Song, Inho; Watanabe, Masato; Hotta, Eiki

    2010-01-01

    Highly efficient and compact pulsed power supply system for a capillary discharge soft x-ray laser (SXRL) has been developed. The system consists of a 2.2 microF two-stage LC inversion generator, a 2:54 step-up transformer, a 3 nF water capacitor, and a discharge section with a few tens of centimeter length capillary. Adoption of the pulsed transformer in combination with the LC inversion generator enables us to use only one gap switch in the circuit for charging the water capacitor up to about 0.5 MV. Furthermore, step-up ratio of a water capacitor voltage to a LC inversion generator initial charging voltage is about 40 with energy transfer efficiency of about 50%. It also leads to good reproducibility of a capillary discharge which is necessary for lasing a SXRL stably. For the study of the possibility of lasing a SXRL at shorter wavelength in a small laboratory scale, high-density and high-temperature plasma column suitable for the laser can be generated relatively easily with this system.

  9. Synthesis and Characterization of WO3/Graphene Nanocomposites for Enhanced Photocatalytic Activities by One-Step In-Situ Hydrothermal Reaction

    Directory of Open Access Journals (Sweden)

    Xiaoxiao Hu

    2018-01-01

    Full Text Available Tungsten trioxide (WO3 nanorods are synthesized on the surface of graphene (GR sheets by using a one-step in-situ hydrothermal method employing sodium tungstate (Na2WO4·2H2O and graphene oxide (GO as precursors. The resulting WO3/GR nanocomposites are characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy, scanning electron microscopy and X-ray photoelectron spectroscopy. The results confirm that the interface between WO3 nanorod and graphene contains chemical bonds. The enhanced optical absorption properties are measured by UV-vis diffuse reflectance spectra. The photocatalytic activity of the WO3/GR nanocomposites under visible light is evaluated by the photodegradation of methylene blue, where the degradation rate of WO3/GR nanocomposites is shown to be double that of pure WO3. This is attributed to the synergistic effect of graphene and the WO3 nanorod, which greatly enhances the photocatalytic performance of the prepared sample, reduces the recombination of the photogenerated electron-hole pairs and increases the visible light absorption efficiency. Finally, the photocatalytic mechanism of the WO3/GR nanocomposites is presented. The synthesis of the prepared sample is convenient, direct and environmentally friendly. The study reports a highly efficient composite photocatalyst for the degradation of contaminants that can be applied to cleaning up the environment.

  10. Why does the Y326I mutant of monoamine oxidase B decompose an endogenous amphetamine at a slower rate than the wild type enzyme? Reaction step elucidated by multiscale molecular simulations.

    Science.gov (United States)

    Pregeljc, Domen; Jug, Urška; Mavri, Janez; Stare, Jernej

    2018-02-07

    This work investigates the Y326I point mutation effect on the kinetics of oxidative deamination of phenylethylamine (PEA) catalyzed by the monoamine oxidase B (MAO B) enzyme. PEA is a neuromodulator capable of affecting the plasticity of the brain and is responsible for the mood enhancing effect caused by physical exercise. Due to a similar functionality, PEA is often regarded as an endogenous amphetamine. The rate limiting step of the deamination was simulated at the multiscale level, employing the Empirical Valence Bond approach for the quantum treatment of the involved valence states, whereas the environment (solvated protein) was represented with a classical force field. A comparison of the reaction free energy profiles delivered by simulation of the reaction in the wild type MAO B and its Y326I mutant yields an increase in the barrier by 1.06 kcal mol -1 upon mutation, corresponding to a roughly 6-fold decrease in the reaction rate. This is in excellent agreement with the experimental kinetic studies. Inspection of simulation trajectories reveals possible sources of the point mutation effect, namely vanishing favorable electrostatic interactions between PEA and a Tyr326 side chain and an increased amount of water molecules at the active site due to the replacement of tyrosine by a less spacious isoleucine residue, thereby increasing the dielectric shielding of the catalytic environment provided by the enzyme.

  11. Microchip capillary electrophoresis with laser-induced fluorescence combined with one-step duplex reverse-transcription polymerase chain reaction for the rapid detection of Enterovirus 71 and Coxsackievirus A16 in throat swab specimens.

    Science.gov (United States)

    Jia, Ruan; Chengjun, Sun; Heng, Chen; Chen, Zhou; Yuanqian, Li; Yongxin, Li

    2015-07-01

    Enterovirus 71 and Coxsackievirus A16 are the main pathogens causing hand-foot-mouth disease. In this paper, microchip capillary electrophoresis with laser-induced fluorescence combined with one-step duplex reverse transcript-polymerase chain reaction has been developed for the detection of Enterovirus 71 and Coxsackievirus A16 in throat swab specimens. The specific reverse transcription-polymerase chain reaction amplicons labeled with SYBR Orange were separated by microchip capillary electrophoresis and detected by laser induced fluorescence detector within 7 min. The intraday and interday relative standard deviation of migration time for DNA Marker was in the range of 1.36-2.94 and 2.78-3.96%, respectively. The detection limits were as low as 2.06 × 10(3) copies/mL for Enterovirus 71 and 5 × 10(3) copies/mL for Coxsackievirus A16. No cross-reactivity was observed with rotavirus, astrovirus, norovirus, and adenovirus, which showed good specificity of the method. This assay was validated using 100 throat swab specimens that were detected by real-time reverse-transcript polymerase chain reaction in parallel and the two methods produced the same results. This study provided a rapid, sensitive and specific method for the detection of Enterovirus 71 and Coxsackievirus A16, which make a contribution to significant time and cost saving for the identification and treatment of patients. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  12. Large scale collective modeling the final 'freeze out' stages of energetic heavy ion reactions and calculation of single particle measurables from these models

    International Nuclear Information System (INIS)

    Nyiri, Agnes

    2005-01-01

    -relativistic heavy ion reactions is an important hadronic observable sensitive to the early stages of system evolution. The flow analysis involves the particles, which have already been frozen out. Therefore, to perform realistic flow computations from the Multi Module Model we need a complete freeze out description and a well identified freeze out surface. However, the freeze out module is still not ready. Although we have not yet been able to evaluate collective flow using the Multi Module Model, the method and code for the calculation of flow components has been worked out in an independent module. This module is completed and can be coupled to the previous modules when those are ready for use. In order to test the code, we have calculated directed and elliptic flow from a tilted, ellipsoidally expanding source using a simple, blast wave type of model. This model was developed directly for this aim based on Buda-Lund hydro models. Although, this oversimplified blast wave model is not suitable to reproduce the experimental data -which will be an important task in the future to check our Multi Module Model-, it has provided us with important information. We have found that the directed flow, is very sensitive to the correct identification of the reaction plane included the determination of the impact parameter vector, and can be misinterpreted by some experimental methods. We have shown that misidentification of the reaction plane may even set the directed flow to zero by construction. We have presented results of the rapidity dependence of the directed flow, v1, and elliptic flow, v2, furthermore, the transverse momentum dependence of v2. We have also investigated the dependence of the flow pattern on the initial geometry of the fireball by calculating flow components from two ellipsoidal sources with the same thermodynamical properties but different shape. The code determining the freeze out hypersurface should still be improved in order to avoid inaccuracies in the further

  13. Large scale collective modeling the final 'freeze out' stages of energetic heavy ion reactions and calculation of single particle measurables from these models

    Energy Technology Data Exchange (ETDEWEB)

    Nyiri, Agnes

    2005-07-01

    -relativistic heavy ion reactions is an important hadronic observable sensitive to the early stages of system evolution. The flow analysis involves the particles, which have already been frozen out. Therefore, to perform realistic flow computations from the Multi Module Model we need a complete freeze out description and a well identified freeze out surface. However, the freeze out module is still not ready. Although we have not yet been able to evaluate collective flow using the Multi Module Model, the method and code for the calculation of flow components has been worked out in an independent module. This module is completed and can be coupled to the previous modules when those are ready for use. In order to test the code, we have calculated directed and elliptic flow from a tilted, ellipsoidally expanding source using a simple, blast wave type of model. This model was developed directly for this aim based on Buda-Lund hydro models. Although, this oversimplified blast wave model is not suitable to reproduce the experimental data--which will be an important task in the future to check our Multi Module Model--it has provided us with important information. We have found that the directed flow, is very sensitive to the correct identification of the reaction plane included the determination of the impact parameter vector, and can be misinterpreted by some experimental methods. We have shown that misidentification of the reaction plane may even set the directed flow to zero by construction. We have presented results of the rapidity dependence of the directed flow, v1, and elliptic flow, v2, furthermore, the transverse momentum dependence of v2. We have also investigated the dependence of the flow pattern on the initial geometry of the fireball by calculating flow components from two ellipsoidal sources with the same thermodynamical properties but different shape. The code determining the freeze out hypersurface should still be improved in order to avoid inaccuracies in the further

  14. Quantitative changes in proteins responsible for flavonoid and anthocyanin biosynthesis in strawberry fruit at different ripening stages: A targeted quantitative proteomic investigation employing multiple reaction monitoring.

    Science.gov (United States)

    Song, Jun; Du, Lina; Li, Li; Kalt, Wilhelmina; Palmer, Leslie Campbell; Fillmore, Sherry; Zhang, Ying; Zhang, ZhaoQi; Li, XiHong

    2015-06-03

    To better understand the regulation of flavonoid and anthocyanin biosynthesis, a targeted quantitative proteomic investigation employing LC-MS with multiple reaction monitoring was conducted on two strawberry cultivars at three ripening stages. This quantitative proteomic workflow was improved through an OFFGEL electrophoresis to fractionate peptides from total protein digests. A total of 154 peptide transitions from 47 peptides covering 21 proteins and isoforms related to anthocyanin biosynthesis were investigated. The normalized protein abundance, which was measured using isotopically-labeled standards, was significantly changed concurrently with increased anthocyanin content and advanced fruit maturity. The protein abundance of phenylalanine ammonia-lyase; anthocyanidin synthase, chalcone isomerase; flavanone 3-hydroxylase; dihydroflavonol 4-reductase, UDP-glucose:flavonoid-3-O-glucosyltransferase, cytochrome c and cytochrome C oxidase subunit 2, was all significantly increased in fruit of more advanced ripeness. An interaction between cultivar and maturity was also shown with respect to chalcone isomerase. The good correlation between protein abundance and anthocyanin content suggested that a metabolic control point may exist for anthocyanin biosynthesis. This research provides insights into the process of anthocyanin formation in strawberry fruit at the level of protein concentration and reveals possible candidates in the regulation of anthocyanin formation during fruit ripening. To gain insight into the molecular mechanisms contributing to flavonoids and anthocyanin biosynthesis and regulation of strawberry fruit during ripening is challenging due to limited molecular biology tools and established hypothesis. Our targeted proteomic approach employing LC-MS/MS analysis and MRM technique to quantify proteins in relation to flavonoids and anthocyanin biosynthesis and regulation in strawberry fruit during fruit ripening is novel. The identification of peptides

  15. Synthesis of Stable and Soluble One-Handed Helical Homopoly(substituted acetylenes without the Coexistence of Any Other Chiral Moieties via Two-Step Polymer Reactions in Membrane State: Molecular Design of the Starting Monomer

    Directory of Open Access Journals (Sweden)

    Takashi Kaneko

    2012-01-01

    Full Text Available A soluble and stable one-handed helical poly(substituted phenylacetylene without the coexistence of any other chiral moieties was successfully synthesized by asymmetric-induced polymerization of a chiral monomer followed by two-step polymer reactions in membrane state: (1 removing the chiral groups (desubstitution; and (2 introduction of achiral long alkyl groups at the same position as the desubstitution to enhance the solubility of the resulting one-handed helical polymer (resubstitution. The starting chiral monomer should have four characteristic substituents: (i a chiral group bonded to an easily hydrolyzed spacer group; (ii two hydroxyl groups; (iii a long rigid hydrophobic spacer between the chiral group and the polymerizing group; (iv a long achiral group near the chiral group. As spacer group a carbonate ester was selected. The two hydroxyl groups formed intramolecular hydrogen bonds stabilizing a one-handed helical structure in solution before and after the two-step polymer reactions in membrane state. The rigid long hydrophobic spacer, a phenylethynylphenyl group, enhanced the solubility of the starting polymer, and realized effective chiral induction from the chiral side groups to the main chain in the asymmetric-induced polymerization. The long alkyl group near the chiral group avoided shrinkage of the membrane and kept the reactivity of resubstitution in membrane state after removing the chiral groups. The g value (g = ([θ]/3,300/ε for the CD signal assigned to the main chain in the obtained final polymer was almost the same as that of the starting polymer in spite of the absence of any other chiral moieties. Moreover, since the one-handed helical structure was maintained by the intramolecular hydrogen bonds in a solution, direct observation of the one-handed helicity of the final homopolymer has been realized in CD for the solution for the first time.

  16. Pressure-driven one-step solid phase-based on-chip sample preparation on a microfabricated plastic device and integration with flow-through polymerase chain reaction (PCR).

    Science.gov (United States)

    Tran, Hong Hanh; Trinh, Kieu The Loan; Lee, Nae Yoon

    2013-10-01

    In this study, we fabricate a monolithic poly(methylmethacrylate) (PMMA) microdevice on which solid phase-based DNA preparation and flow-through polymerase chain reaction (PCR) units were functionally integrated for one-step sample preparation and amplification operated by pressure. Chelex resin, which is used as a solid support for DNA preparation, can capture denatured proteins but releases DNA, and the purified DNA can then be used as a template in a subsequent amplification process. Using the PMMA microdevices, DNA was successfully purified from both Escherichia coli and human hair sample, and the plasmid vector inserted in E. coli and the D1S80 locus in human genomic DNA were successfully amplified from on-chip purified E. coli and human hair samples. Furthermore, the integration potential of the proposed sample preparation and flow-through PCR units was successfully demonstrate on a monolithic PMMA microdevice with a seamless flow, which could pave the way for a pressure-driven, simple one-step sample preparation and amplification with greatly decreased manufacture cost and enhanced device disposability. Copyright © 2013 Elsevier B.V. All rights reserved.

  17. Step sites in syngas catalysis

    DEFF Research Database (Denmark)

    Rostrup-Nielsen, J.; Nørskov, Jens Kehlet

    2006-01-01

    Step sites play an important role in many catalytic reactions. This paper reviews recent results on metal catalysts for syngas reactions with emphasis on steam reforming. Modern characterization techniques (STEM, HREM...) and theoretical calculations (DFT) has allowed a more quantitative explanat...

  18. Biomaterial Encapsulation Is Enhanced in the Early Stages of the Foreign Body Reaction During Conditional Macrophage Depletion in Transgenic Macrophage Fas-Induced Apoptosis Mice

    NARCIS (Netherlands)

    Bank, Ruud A.; Zandstra, Jurjen; Room, Hilde; Petersen, Arjen H.; van Putten, Sander M.

    2017-01-01

    Macrophages are pivotal cells during the foreign body reaction (FBR), as they orchestrate the proinflammatory microenvironment inside and around biomaterials by secretion of inflammatory mediators. Furthermore, they are responsible for the degradation of biomaterials and are thought to instruct the

  19. [The biological reaction of inflammation, methylglyoxal of blood plasma, functional and structural alterations in elastic type arteries at the early stage of hypertension disease].

    Science.gov (United States)

    Titov, V N; Dmitriev, V A; Oshchepkov, E V; Balakhonova, T V; Tripoten', M I; Shiriaeva, Iu K

    2012-08-01

    The article deals with studying of the relationship between biologic reaction of inflammation with glycosylation reaction and content of methylglyoxal in blood serum. The positive correlation between pulse wave velocity and content of methylglyoxal, C-reactive protein in intercellular medium and malleolar brachial index value was established. This data matches the experimental results concerning involvement of biological reaction of inflammation into structural changes of elastic type arteries under hypertension disease, formation of arteries' rigidity and increase of pulse wave velocity. The arterial blood pressure is a biological reaction of hydrodynamic pressure which is used in vivo by several biological functions: biological function of homeostasis, function of endoecology, biological function of adaptation and function of locomotion. The biological reaction of hydrodynamic (hydraulic) pressure is a mode of compensation of derangement of several biological functions which results in the very high rate of hypertension disease in population. As a matter of fact, hypertension disease is a syndrome of lingering pathological compensation by higher arterial blood pressure of the biological functions derangements occurring in the distal section at the level of paracrine cenoses of cells. The arterial blood pressure is a kind of in vivo integral indicator of deranged metabolism. The essential hypertension disease pathogenically is a result of the derangement of three biological functions: biological function of homeostasis, biological function of trophology - nutrition (biological reaction of external feeding - exotrophia) and biological function of endoecology. In case of "littering" of intercellular medium in vivo with nonspecific endogenic flogogens a phylogenetically earlier activation of biological reactions of excretion, inflammation and hydrodynamic arterial blood pressure occur. In case of derangement of biological function of homeostasis, decreasing of

  20. One-step synthesis of shell/core structural boron and nitrogen co-doped graphitic carbon/nanodiamond as efficient electrocatalyst for the oxygen reduction reaction in alkaline media

    International Nuclear Information System (INIS)

    Liu, Xiaoxu; Wang, Yanhui; Dong, Liang; Chen, Xi; Xin, Guoxiang; Zhang, Yan; Zang, Jianbing

    2016-01-01

    Shell/core structural boron and nitrogen co-doped graphitic carbon/nanodiamond (BN-C/ND) non-noble metal catalyst has been synthesized by a simple one-step heat-treatment of the mixture with nanodiamond, melamine, boric acid and FeCl 3 . In the process of the surface graphitization of nanodiamond with catalysis by FeCl 3 , B and N atoms from the decomposition of boric acid and melamine were directly introduced into the graphite lattice to form B, N co-doped graphitic carbon shell, while the core still retained the diamond structure. Electrochemical measurements of the BN-C/ND catalyst show much higher electrocatalytic activities towards oxygen reduction reaction (ORR) in alkaline medium than its analogues doped with B or N alone (B-C/ND or N-C/ND). The high catalytic activity of BN-C/ND is attributed to the synergetic effect caused by co-doping of C/ND with B and N. Meanwhile, the BN-C/ND exhibits an excellent electrochemical stability due to the special shell/core structure. There is almost no alteration occurred in the cyclic voltammetry measurements for BN-C/ND before and after 5000 cycles. All experimental results prove that the BN-C/ND may be exploited as a potentially efficient and inexpensive non-noble metal cathode catalyst for ORR to substitute Pt-based catalysts in fuel cells.

  1. Early stages of the decomposition reaction in a Ni-13%Al alloy - polazired small-angle neutron scattering and clusterdynamic modelling; Fruehstadien der Entmischung in einer Ni-13at%Al-Legierung - polarisierte Neutronen-Kleinwinkelstreuung und clusterdynamische Modellierung

    Energy Technology Data Exchange (ETDEWEB)

    Staron, P. [GKSS-Forschungszentrum Geesthacht GmbH (Germany). Inst. fuer Werkstofforschung

    1997-12-31

    In this work the early stages of the decomposition reaction in a supersaturated Ni-13at%Al alloy at temperatures of 450, 500 and 550 C were investigated by means of small and wide-angle scattering of polarized neutrons. To determine the early stage decomposition kinetics requires the size distributions of extremely small precipitate clusters to be measured. By measuring over an appropriate region of scattering vectors and reducing the incoherent background with an isotopically taylored sample, size distributions of clusters with radii as small as 0.4 nm could be determined. A model which describes the formation of ordered precipitates in alloys with a low nucleation energy (like Ni-Al) is required to interpret the measured decomposition kinetics. In the present work a cluster-dynamics model was for the first time used to study the decomposition in Ni-Al alloys. The clusterdynamic modelling of the measured decomposition kinetics, as well as a reinterpretation of the results of former investigations, has shown that the character of the decomposition reaction in supersaturated Ni-Al alloys strongly depends on their initial supersaturation. Classical nucleation only occurs at low initial supersaturations. As the initial supersaturation increases, the classical nucleation reaction turns into a continuous coarsening of an initial size distribution of nucleation-free formed clusters. (orig.) 62 refs.

  2. Staged Repository Development Programmes

    International Nuclear Information System (INIS)

    Isaacs, T

    2003-01-01

    Programs to manage and ultimately dispose of high-level radioactive wastes are unique from scientific and technological as well as socio-political aspects. From a scientific and technological perspective, high-level radioactive wastes remain potentially hazardous for geological time periods-many millennia-and scientific and technological programs must be put in place that result in a system that provides high confidence that the wastes will be isolated from the accessible environment for these many thousands of years. Of course, ''proof'' in the classical sense is not possible at the outset, since the performance of the system can only be known with assurance, if ever, after the waste has been emplaced for those geological time periods. Adding to this challenge, many uncertainties exist in both the natural and engineered systems that are intended to isolate the wastes, and some of the uncertainties will remain regardless of the time and expense in attempting to characterize the system and assess its performance. What was perhaps underappreciated in the early days of waste management and repository program development were the unique and intense reactions that the institutional, political, and public bodies would have to repository program development, particularly in programs attempting to identify and then select sites for characterization, design, licensing, and ultimate development. Reactions in most nations were strong, focused, unrelenting, and often successful in hindering, derailing, and even stopping national repository programs. The reasons for such reactions and the measures to successfully respond to them are still evolving and continue to be the focus of many national program and political leaders. Adaptive Staging suggests an approach to repository program development that reflects the unique challenges associated with the disposal of high-level radioactive waste. The step-wise, incremental, learn-as-you-go approach is intended to maximize the

  3. Application of stepping motor

    International Nuclear Information System (INIS)

    1980-10-01

    This book is divided into three parts, which is about practical using of stepping motor. The first part has six chapters. The contents of the first part are about stepping motor, classification of stepping motor, basic theory og stepping motor, characteristic and basic words, types and characteristic of stepping motor in hybrid type and basic control of stepping motor. The second part deals with application of stepping motor with hardware of stepping motor control, stepping motor control by microcomputer and software of stepping motor control. The last part mentions choice of stepping motor system, examples of stepping motor, measurement of stepping motor and practical cases of application of stepping motor.

  4. Curiosidades sobre a reação aldólica utilizada como etapa chave na síntese Brasileira dos ácidos pterídicos A e B Curiosities about the aldol reaction employed as a key step in the synthesis of pteridic acids A and B

    Directory of Open Access Journals (Sweden)

    Luiz C. Dias

    2010-01-01

    Full Text Available This work describes an overview of our synthesis of pteridic acids A and B and discloses some interesting results related to the lithium enolate-mediated aldol reaction used as key step to set up the C5-C15 fragment of these natural products. This first example, as far we know, of an aldol reaction between a chiral enolate of a (Z enone and a chiral aldehyde has driven us to a series of experiments showing the remarkable relation between enolization selectivity and reaction conditions.

  5. Maillard Reaction: review

    Directory of Open Access Journals (Sweden)

    Júlia d'Almeida Francisquini

    2017-11-01

    Full Text Available Maillard reaction is an important subject of study in food science and technology and different areas of knowledge are involved such as chemistry, food engineering, nutrition and food technology. The objective of this paper is to present the basic concepts of the Maillard reaction, such as the reaction stages, the main compounds producced and some technological consequences for dairy products.

  6. Biodiesel production by two-stage transesterification with ethanol.

    Science.gov (United States)

    Mendow, G; Veizaga, N S; Sánchez, B S; Querini, C A

    2011-11-01

    A two-stage process consisting of two reactions steps with glycerin separation and ethanol/catalyst addition in each of them was optimized for ethyl esters production. The optimal reaction temperature was 55 °C. At an ethanol/oil molar ratio of 4.25:1 (25%v/v alcohol with respect to oil), a 99% conversion value was obtained with low ethanol consumption. In contrast to methoxide catalysts, sodium and potassium hydroxide catalysts severely complicate the purification since no phase separation took place under most conditions. With a total sodium methoxide concentration of 1.06 g catalyst/100 g oil, and adding 50% of the catalyst in each reaction step, biodiesel with a total glycerin content of 0.172% was obtained. The optimal conditions found in this study make it possible to use the same industrial facility to produce either methyl or ethyl esters. Copyright © 2011 Elsevier Ltd. All rights reserved.

  7. Characterization of long-circulating cationic nanoparticle formulations consisting of a two-stage PEGylation step for the delivery of siRNA in a breast cancer tumor model.

    Science.gov (United States)

    Ho, Emmanuel A; Osooly, Maryam; Strutt, Dita; Masin, Dana; Yang, Youngjoo; Yan, Hong; Bally, Marcel

    2013-01-01

    Polyethylene glycol (PEG) has been used widely in liposomal formulations as a strategy to inhibit opsonization by plasma proteins and to prolong liposome plasma circulation time. PEG can be incorporated onto the surface of liposomes either during the spontaneous self-assembling process or inserted after vesicle formation. The advantages of employing the PEG postinsertion method include improved drug encapsulation efficiency and the ability to incorporate PEG conjugates for enhanced cell binding and uptake. In this study, we propose to evaluate a cationic lipid nanoparticle formulation containing two PEGylation steps: pre- and post-siRNA insertion. Our results indicate that formulations consisting of the extra PEG post-insertion step significantly increased siRNA circulation in the plasma by two-folds in comparison with the formulations consisting of only the single PEGylation step. Moreover, this formulation was able to efficiently carry siRNA to the tumor site, increase siRNA stability and significantly downregulate luciferase mRNA expression by >50% when compared with the controls in an intraperitoneal and subcutaneous breast cancer tumor model. Overall, our cationic lipid nanoparticle formulation displayed enhanced plasma circulation, reduced liver accumulation, enhanced tumor targeting, and effective gene knockdown--demonstrating excellent utility for the delivery of siRNA. Copyright © 2012 Wiley Periodicals, Inc.

  8. Development of active, and stable water-gas-shift reaction catalysts for fuel cell applications

    NARCIS (Netherlands)

    Azzam, K.G.H.; Babich, Igor V.; Seshan, Kulathu Iyer; Lefferts, Leon

    2006-01-01

    Water-gas-shift (WGS) reaction CO + H2O = CO2 + H2, is a key step in the generation of H2 for fuel cells. Noble metal-based catalysts are promising single stage WGS catalysts because they less sensitive than LTS catalysts (Cu based) and more active than the HTS (Ni) catalysts. High activity in CO

  9. Maximizing Efficiency in Two-step Solar-thermochemical Fuel Production

    Energy Technology Data Exchange (ETDEWEB)

    Ermanoski, I. [Sandia National Laboratories (SNL-NM), Albuquerque, NM (United States)

    2015-05-01

    Widespread solar fuel production depends on its economic viability, largely driven by the solar-to-fuel conversion efficiency. In this paper, the material and energy requirements in two-step solar-thermochemical cycles are considered.The need for advanced redox active materials is demonstrated, by considering the oxide mass flow requirements at a large scale. Two approaches are also identified for maximizing the efficiency: optimizing reaction temperatures, and minimizing the pressure in the thermal reduction step by staged thermal reduction. The results show that each approach individually, and especially the two in conjunction, result in significant efficiency gains.

  10. Double-blind, placebo-controlled first in human study to investigate an oral vaccine aimed to elicit an immune reaction against the VEGF-Receptor 2 in patients with stage IV and locally advanced pancreatic cancer

    International Nuclear Information System (INIS)

    Niethammer, Andreas G; Springer, Marco; Grenacher, Lars; Buchler, Markus W; Koch, Moritz; Weitz, Jürgen; Haefeli, Walter E; Schmitz-Winnenthal, Friedrich H; Lubenau, Heinz; Mikus, Gerd; Knebel, Philipp; Hohmann, Nicolas; Leowardi, Christine; Beckhove, Philipp; Akhisaroglu, Mustafa; Ge, Yingzi

    2012-01-01

    The investigational oral DNA vaccine VXM01 targets the vascular endothelial growth factor receptor 2 (VEGFR-2) and uses Salmonella typhi Ty21a as a vector. The immune reaction elicited by VXM01 is expected to disrupt the tumor neovasculature and, consequently, inhibit tumor growth. VXM01 potentially combines the advantages of anti-angiogenic therapy and active immunotherapy. This phase I trial examines the safety, tolerability, and immunological and clinical responses to VXM01. The randomized, placebo-controlled, double blind dose-escalation study includes up to 45 patients with locally advanced and stage IV pancreatic cancer. The patients will receive four doses of VXM01 or placebo in addition to gemcitabine as standard of care. Doses from 10 6 cfu up to 10 10 cfu of VXM01 will be evaluated in the study. An independent data safety monitoring board (DSMB) will be involved in the dose-escalation decisions. In addition to safety as primary endpoint, the VXM01-specific immune reaction, as well as clinical response parameters will be evaluated. The results of this study shall provide the first data regarding the safety and immunogenicity of the oral anti-VEGFR-2 vaccine VXM01 in cancer patients. They will also define the recommended dose for phase II and provide the basis for further clinical evaluation, which may also include additional cancer indications. EudraCT No.: 2011-000222-29, NCT01486329, ISRCTN68809279

  11. Kinetics and selectivity of the oxidation of methylbenzenes in Co(III)-CH3COOH-CF3COOH solutions. Comparison with nitration and hydroxylation reactions

    International Nuclear Information System (INIS)

    Rudakov, E.S.; Lobachev, V.L.

    1989-01-01

    Data have been obtained concerning the kinetics, substrate selectivity, and kinetic isotope effect for the first stage in the oxidation of a series of arenes, from benzene to hexamethylbenzene, by Co(III) acetate in CH 3 COOH-CF 3 COOH (1.9 M) solutions at 25 degree C. A similarity was noted between substrate selectivity for reactions of alkylbenzenes with Co(III) and electrophilic nitration reactions, which occur via an electron transfer step. It was also found that substrate selectivity for these reactions differs significantly from that found for electrophilic hydroxylation reactions, which occur via an intermediate slow step involving σ-complex formation

  12. Highly Convergent Total Synthesis of (+)-Lithospermic Acid via a Late-Stage Intermolecular C–H Olefination

    Science.gov (United States)

    Wang, Dong-Hui; Yu, Jin-Quan

    2011-01-01

    The total synthesis of (+)-lithospermic acid is reported, which exploits two successive C–H activation reactions as the key steps. Rh-catalyzed carbene C–H insertion reaction using Davies’ catalyst built the dihydrobenzofuran core, and a late-stage intermolecular C–H olefination coupled the olefin unit with the dihydrobenzofuran core to construct the molecule in a highly convergent manner. PMID:21443224

  13. Linac project - actual stage

    International Nuclear Information System (INIS)

    Carlin Filho, N.

    1990-01-01

    The actual development stage of Pelletron accelerator to study heavy ion reactions, nuclear structures and applied nuclear physics is presented. The construction of acceleration systems able to provide beams of several mass and energies up to 20 MeV/A, is discussed, describing acceleration structures and implemented systems. (M.C.K.)

  14. The way to collisions, step by step

    CERN Multimedia

    2009-01-01

    While the LHC sectors cool down and reach the cryogenic operating temperature, spirits are warming up as we all eagerly await the first collisions. No reason to hurry, though. Making particles collide involves the complex manoeuvring of thousands of delicate components. The experts will make it happen using a step-by-step approach.

  15. Step-Growth Polymerization.

    Science.gov (United States)

    Stille, J. K.

    1981-01-01

    Following a comparison of chain-growth and step-growth polymerization, focuses on the latter process by describing requirements for high molecular weight, step-growth polymerization kinetics, synthesis and molecular weight distribution of some linear step-growth polymers, and three-dimensional network step-growth polymers. (JN)

  16. Stepping motor controller

    Science.gov (United States)

    Bourret, Steven C.; Swansen, James E.

    1984-01-01

    A stepping motor is microprocessingly controlled by digital circuitry which monitors the output of a shaft encoder adjustably secured to the stepping motor and generates a subsequent stepping pulse only after the preceding step has occurred and a fixed delay has expired. The fixed delay is variable on a real-time basis to provide for smooth and controlled deceleration.

  17. Trading stages

    DEFF Research Database (Denmark)

    Steiner, Uli; Tuljapurkar, Shripad; Coulson, Tim

    2012-01-01

    because they are hard to use and interpret, and tools for age and stage structured populations are missing. We present easily interpretable expressions for the sensitivities and elasticities of life expectancy to vital rates in age-stage models, and illustrate their application with two biological......Interest in stage-and age structured models has recently increased because they can describe quantitative traits such as size that are left out of age-only demography. Available methods for the analysis of effects of vital rates on lifespan in stage-structured models have not been widely applied...... examples. Much of our approach relies on trading of time and mortality risk in one stage for time and risk in others. Our approach contributes to the new framework of the study of age- and stage-structured biodemography....

  18. Microsoft Office professional 2010 step by step

    CERN Document Server

    Cox, Joyce; Frye, Curtis

    2011-01-01

    Teach yourself exactly what you need to know about using Office Professional 2010-one step at a time! With STEP BY STEP, you build and practice new skills hands-on, at your own pace. Covering Microsoft Word, PowerPoint, Outlook, Excel, Access, Publisher, and OneNote, this book will help you learn the core features and capabilities needed to: Create attractive documents, publications, and spreadsheetsManage your e-mail, calendar, meetings, and communicationsPut your business data to workDevelop and deliver great presentationsOrganize your ideas and notes in one placeConnect, share, and accom

  19. Exploratory Research on Novel Coal Liquefaction Concept - Task 2: Evaluation of Process Steps.

    Energy Technology Data Exchange (ETDEWEB)

    Brandes, S.D.; Winschel, R.A.

    1997-05-01

    A novel direct coal liquefaction technology is being investigated in a program being conducted by CONSOL Inc. with the University of Kentucky, Center for Applied Energy Research and LDP Associates under DOE Contract DE-AC22-95PC95050. The novel concept consists of a new approach to coal liquefaction chemistry which avoids some of the inherent limitations of current high-temperature thermal liquefaction processes. The chemistry employed is based on hydride ion donation to solubilize coal at temperatures (350-400{degrees}C) significantly lower than those typically used in conventional coal liquefaction. The process concept being explored consists of two reaction stages. In the first stage, the coal is solubilized by hydride ion donation. In the second, the products are catalytically upgraded to acceptable refinery feedstocks. The program explores not only the initial solubilization step, but integration of the subsequent processing steps, including an interstage solids-separation step, to produce distillate products. A unique feature of the process concept is that many of the individual reaction steps can be decoupled, because little recycle around the liquefaction system is expected. This allows for considerable latitude in the process design. Furthermore, this has allowed for each key element in the process to be explored independently in laboratory work conducted under Task 2 of the program.

  20. On Computational Small Steps and Big Steps

    DEFF Research Database (Denmark)

    Johannsen, Jacob

    rules in the small-step semantics cause the refocusing step of the syntactic correspondence to be inapplicable. Second, we propose two solutions to overcome this in-applicability: backtracking and rule generalization. Third, we show how these solutions affect the other transformations of the two......We study the relationship between small-step semantics, big-step semantics and abstract machines, for programming languages that employ an outermost reduction strategy, i.e., languages where reductions near the root of the abstract syntax tree are performed before reductions near the leaves....... In particular, we investigate how Biernacka and Danvy’s syntactic correspondence and Reynolds’s functional correspondence can be applied to interderive semantic specifications for such languages. The main contribution of this dissertation is three-fold: First, we identify that backward overlapping reduction...

  1. Analysis of mechanism of complex chemical reaction taking radiation chemical purification of gases from impurities as an example

    International Nuclear Information System (INIS)

    Gerasimov, G.Ya.; Makarov, V.N.

    1997-01-01

    Algorithm of selecting optimal mechanism of complex chemical reaction, enabling to reduce the number of its stages, is suggested. Main steps of constructing the kinetic model of the medium are considered, taking the radiation chemical purification (using fast electron radiation) of gases (N 2 , CO 2 , O 2 and others) from impurities as an example. 17 refs., 3 figs., 2 tabs

  2. A Reaction Database for Small Molecule Pharmaceutical Processes Integrated with Process Information

    Directory of Open Access Journals (Sweden)

    Emmanouil Papadakis

    2017-10-01

    Full Text Available This article describes the development of a reaction database with the objective to collect data for multiphase reactions involved in small molecule pharmaceutical processes with a search engine to retrieve necessary data in investigations of reaction-separation schemes, such as the role of organic solvents in reaction performance improvement. The focus of this reaction database is to provide a data rich environment with process information available to assist during the early stage synthesis of pharmaceutical products. The database is structured in terms of reaction classification of reaction types; compounds participating in the reaction; use of organic solvents and their function; information for single step and multistep reactions; target products; reaction conditions and reaction data. Information for reactor scale-up together with information for the separation and other relevant information for each reaction and reference are also available in the database. Additionally, the retrieved information obtained from the database can be evaluated in terms of sustainability using well-known “green” metrics published in the scientific literature. The application of the database is illustrated through the synthesis of ibuprofen, for which data on different reaction pathways have been retrieved from the database and compared using “green” chemistry metrics.

  3. Two Step Wittig/Dihydroxylation Synthetic Route to Higher Sugars

    DEFF Research Database (Denmark)

    Jørgensen, Morten; Madsen, Robert

    1999-01-01

    Higher carbon sugars are obtained by a two carbon, two step chain elongation of aldoses involving first a Wittig reaction and then an osmium tetroxide catalyzed dihydroxylation......Higher carbon sugars are obtained by a two carbon, two step chain elongation of aldoses involving first a Wittig reaction and then an osmium tetroxide catalyzed dihydroxylation...

  4. Step by Step Microsoft Office Visio 2003

    CERN Document Server

    Lemke, Judy

    2004-01-01

    Experience learning made easy-and quickly teach yourself how to use Visio 2003, the Microsoft Office business and technical diagramming program. With STEP BY STEP, you can take just the lessons you need, or work from cover to cover. Either way, you drive the instruction-building and practicing the skills you need, just when you need them! Produce computer network diagrams, organization charts, floor plans, and moreUse templates to create new diagrams and drawings quicklyAdd text, color, and 1-D and 2-D shapesInsert graphics and pictures, such as company logosConnect shapes to create a basic f

  5. Staging atmospheres

    DEFF Research Database (Denmark)

    Bille, Mikkel; Bjerregaard, Peter; Sørensen, Tim Flohr

    2015-01-01

    The article introduces the special issue on staging atmospheres by surveying the philosophical, political and anthropological literature on atmosphere, and explores the relationship between atmosphere, material culture, subjectivity and affect. Atmosphere seems to occupy one of the classic...

  6. Diabetes PSA (:30) Step By Step

    Centers for Disease Control (CDC) Podcasts

    2009-10-24

    First steps to preventing diabetes. For Hispanic and Latino American audiences.  Created: 10/24/2009 by National Diabetes Education Program (NDEP), a joint program of the Centers for Disease Control and Prevention and the National Institutes of Health.   Date Released: 10/24/2009.

  7. Diabetes PSA (:60) Step By Step

    Centers for Disease Control (CDC) Podcasts

    2009-10-24

    First steps to preventing diabetes. For Hispanic and Latino American audiences.  Created: 10/24/2009 by National Diabetes Education Program (NDEP), a joint program of the Centers for Disease Control and Prevention and the National Institutes of Health.   Date Released: 10/24/2009.

  8. Reaction Automata

    OpenAIRE

    Okubo, Fumiya; Kobayashi, Satoshi; Yokomori, Takashi

    2011-01-01

    Reaction systems are a formal model that has been introduced to investigate the interactive behaviors of biochemical reactions. Based on the formal framework of reaction systems, we propose new computing models called reaction automata that feature (string) language acceptors with multiset manipulation as a computing mechanism, and show that reaction automata are computationally Turing universal. Further, some subclasses of reaction automata with space complexity are investigated and their la...

  9. Fast-Rate Capable Electrode Material with Higher Energy Density than LiFePO4: 4.2V LiVPO4F Synthesized by Scalable Single-Step Solid-State Reaction.

    Science.gov (United States)

    Kim, Minkyung; Lee, Seongsu; Kang, Byoungwoo

    2016-03-01

    Use of compounds that contain fluorine (F) as electrode materials in lithium ion batteries has been considered, but synthesizing single-phase samples of these compounds is a difficult task. Here, it is demonstrated that a simple scalable single-step solid-state process with additional fluorine source can obtain highly pure LiVPO 4 F. The resulting material with submicron particles achieves very high rate capability ≈100 mAh g -1 at 60 C-rate (1-min discharge) and even at 200 C-rate (18 s discharge). It retains superior capacity, ≈120 mAh g -1 at 10 C charge/10 C discharge rate (6-min) for 500 cycles with >95% retention efficiency. Furthermore, LiVPO 4 F shows low polarization even at high rates leading to higher operating potential >3.45 V (≈3.6 V at 60 C-rate), so it achieves high energy density. It is demonstrated for the first time that highly pure LiVPO 4 F can achieve high power capability comparable to LiFePO 4 and much higher energy density (≈521 Wh g -1 at 20 C-rate) than LiFePO 4 even without nanostructured particles. LiVPO 4 F can be a real substitute of LiFePO 4.

  10. [the Pterional Craniotomy: Step By Step].

    OpenAIRE

    Chaddad Neto, Feres; Ribas, Guilherme Carvalhal; Oliveira, Evandro de

    2015-01-01

    This article intends to describe in a didactical and practical manner the frontotemporosphenoidal craniotomy, that is usually known as pterional craniotomy and that constitute the cranial approach mostly utilized in the modern neurosurgery. This is then basically a descriptive text, divided according to the main stages involved in this procedure, and that describes with details how the authors currently perform this craniotomy.

  11. Self Blocking of CO Dissociation on a Stepped Ruthenium Surface

    DEFF Research Database (Denmark)

    Vendelbo, Søren Bastholm; Johansson, Martin; Mowbray, Duncan

    2010-01-01

    reaction only occurs on the steps. Under ultra high vacuum (UHV) conditions CO dissociates on the step, the oxygen reacts with CO to form CO2 and the residual carbon blocks the step from further CO dissociation. This mechanism competes with the recombination of carbon and oxygen. At high CO pressures, we......The influence of steps on CO reactions has been studied on a Ru(0 1 (1) over bar 5 4) single crystal with a step density of 4%. Based on temperature programmed desorption (TPD) and oxygen titration experiments as well as density functional theory (DFT) calculations, we show that the CO dissociation...... find step blocking no longer dominates the CO dissociation reaction to the same extent and further carbon uptake is observed. This self-poisoning effect is discussed in relation to similar studies of Ni(14 13 13) where such effects were not observed. We find the apparent dissociation energy on the step...

  12. Staged multidisciplinary step-up management for necrotizing pancreatitis

    NARCIS (Netherlands)

    da Costa, D. W.; Boerma, D.; van Santvoort, H. C.; Horvath, K. D.; Werner, J.; Carter, C. R.; Bollen, T. L.; Gooszen, H. G.; Besselink, M. G.; Bakker, O. J.

    2014-01-01

    Some 15 per cent of all patients with acute pancreatitis develop necrotizing pancreatitis, with potentially significant consequences for both patients and healthcare services. This review summarizes the latest insights into the surgical and medical management of necrotizing pancreatitis. General

  13. Staged multidisciplinary step-up management for necrotizing pancreatitis

    NARCIS (Netherlands)

    Costa, D.W. da; Boerma, D.; Santvoort, H.C. van; Horvath, K.D.; Werner, J.; Carter, C.R.; Bollen, T.L.; Gooszen, H.G.; Besselink, M.G.; Bakker, O.J.

    2014-01-01

    BACKGROUND: Some 15 per cent of all patients with acute pancreatitis develop necrotizing pancreatitis, with potentially significant consequences for both patients and healthcare services. METHODS: This review summarizes the latest insights into the surgical and medical management of necrotizing

  14. Microsoft Office Word 2007 step by step

    CERN Document Server

    Cox, Joyce

    2007-01-01

    Experience learning made easy-and quickly teach yourself how to create impressive documents with Word 2007. With Step By Step, you set the pace-building and practicing the skills you need, just when you need them!Apply styles and themes to your document for a polished lookAdd graphics and text effects-and see a live previewOrganize information with new SmartArt diagrams and chartsInsert references, footnotes, indexes, a table of contentsSend documents for review and manage revisionsTurn your ideas into blogs, Web pages, and moreYour all-in-one learning experience includes:Files for building sk

  15. Evaluation of virus isolation, one-step real-time reverse transcription polymerase chain reaction assay, and two rapid influenza diagnostic tests for detecting canine Influenza A virus H3N8 shedding in dogs.

    Science.gov (United States)

    Pecoraro, Heidi L; Spindel, Miranda E; Bennett, Susi; Lunn, Katharine F; Landolt, Gabriele A

    2013-05-01

    Sustained transmission of canine Influenza A virus (CIV) H3N8 among U.S. dogs underscores the threat influenza continues to pose to canine health. Because rapid and accurate detection of infection is critical to the diagnosis and control of CIV, the 2 main objectives of the current study were to estimate and compare the sensitivities of CIV testing methods on canine swab samples and to evaluate the performance of Flu Detect™ (Synbiotics Corp., Kansas City, MO) for detecting CIV nasal shedding in high-risk shelter dogs. To address the first objective, nasal and pharyngeal swab samples were collected from 124 shelter and household dogs seen by Colorado State University Veterinary Teaching Hospital clinicians for canine infectious respiratory disease between April 2006 and March 2007 and tested for CIV shedding using virus isolation, the rapid influenza diagnostic test Directigen Flu A+B™ (BD Diagnostic Systems, Sparks, MD), and real-time reverse transcription polymerase chain reaction (RT-PCR). For the second objective, 1,372 dogs with unknown respiratory health status were sampled from 6 U.S. shelters from December 2009 to November 2010. Samples were tested for presence of CIV using real-time RT-PCR and Flu Detect. Using a stochastic latent class modeling approach, the median sensitivities of virus isolation, rapid influenza diagnostic test, and real-time RT-PCR were 72%, 65%, and 95%, respectively. The Flu Detect test performed poorly for detecting CIV nasal shedding compared to real-time RT-PCR. In conclusion, the real-time RT-PCR has the highest sensitivity for detecting virus nasal shedding and can be used as a rapid diagnostic test for CIV.

  16. Diffusion-controlled reactions modeling in Geant4-DNA

    International Nuclear Information System (INIS)

    Karamitros, M.; Luan, S.; Bernal, M.A.; Allison, J.; Baldacchino, G.; Davidkova, M.; Francis, Z.; Friedland, W.; Ivantchenko, V.; Ivantchenko, A.; Mantero, A.; Nieminem, P.; Santin, G.; Tran, H.N.; Stepan, V.; Incerti, S.

    2014-01-01

    Context Under irradiation, a biological system undergoes a cascade of chemical reactions that can lead to an alteration of its normal operation. There are different types of radiation and many competing reactions. As a result the kinetics of chemical species is extremely complex. The simulation becomes then a powerful tool which, by describing the basic principles of chemical reactions, can reveal the dynamics of the macroscopic system. To understand the dynamics of biological systems under radiation, since the 80s there have been on-going efforts carried out by several research groups to establish a mechanistic model that consists in describing all the physical, chemical and biological phenomena following the irradiation of single cells. This approach is generally divided into a succession of stages that follow each other in time: (1) the physical stage, where the ionizing particles interact directly with the biological material; (2) the physico-chemical stage, where the targeted molecules release their energy by dissociating, creating new chemical species; (3) the chemical stage, where the new chemical species interact with each other or with the biomolecules; (4) the biological stage, where the repairing mechanisms of the cell come into play. This article focuses on the modeling of the chemical stage. Method This article presents a general method of speeding-up chemical reaction simulations in fluids based on the Smoluchowski equation and Monte-Carlo methods, where all molecules are explicitly simulated and the solvent is treated as a continuum. The model describes diffusion-controlled reactions. This method has been implemented in Geant4-DNA. The keys to the new algorithm include: (1) the combination of a method to compute time steps dynamically with a Brownian bridge process to account for chemical reactions, which avoids costly fixed time step simulations; (2) a k–d tree data structure for quickly locating, for a given molecule, its closest reactants. The

  17. Staging Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    In recent years, the social sciences have taken a “mobilities turn.” There has been a developing realisation that mobilities do not “just happen.” Mobilities are carefully and meticulously designed, planned and staged (from above). However, they are equally importantly acted out, performed and li......, the book asks: what are the physical, social, technical, and cultural conditions to the staging of contemporary urban mobilities?...... that mobility is more than movement between point A and B. It explores how the movement of people, goods, information, and signs influences human understandings of self, other and the built environment. Moving towards a new understanding of the relationship between movement, interaction and environments...

  18. Building a Data Warehouse step by step

    Directory of Open Access Journals (Sweden)

    2007-01-01

    Full Text Available Data warehouses have been developed to answer the increasing demands of quality information required by the top managers and economic analysts of organizations. Their importance in now a day business area is unanimous recognized, being the foundation for developing business intelligence systems. Data warehouses offer support for decision-making process, allowing complex analyses which cannot be properly achieved from operational systems. This paper presents the ways in which a data warehouse may be developed and the stages of building it.

  19. Transient behavior of devolatilization and char reaction during steam gasification of biomass.

    Science.gov (United States)

    Moon, Jihong; Lee, Jeungwoo; Lee, Uendo; Hwang, Jungho

    2013-04-01

    Steam gasification of biomass is a promising method for producing high quality syngas for polygeneration. During the steam gasification, devolatilization and char reaction are key steps of syngas production and the contributions of the two reactions are highly related to gasification conditions. In this study, the transient characteristics of devolatilization and char reaction in biomass steam gasification were investigated by monitoring cumulative gas production and composition changes in terms of reaction temperature and S/B ratio. Contribution of each reaction stage on the product gas yield was studied in detail. The results provide important insight for understanding the complex nature of biomass gasification and will guide future improvements to the biomass gasification process. Copyright © 2013 Elsevier Ltd. All rights reserved.

  20. Computational Abstraction Steps

    DEFF Research Database (Denmark)

    Thomsen, Lone Leth; Thomsen, Bent; Nørmark, Kurt

    2010-01-01

    and class instantiations. Our teaching experience shows that many novice programmers find it difficult to write programs with abstractions that materialise to concrete objects later in the development process. The contribution of this paper is the idea of initiating a programming process by creating......In this paper we discuss computational abstraction steps as a way to create class abstractions from concrete objects, and from examples. Computational abstraction steps are regarded as symmetric counterparts to computational concretisation steps, which are well-known in terms of function calls...

  1. Focal cryotherapy: step by step technique description.

    Science.gov (United States)

    Redondo, Cristina; Srougi, Victor; da Costa, José Batista; Baghdad, Mohammed; Velilla, Guillermo; Nunes-Silva, Igor; Bergerat, Sebastien; Garcia-Barreras, Silvia; Rozet, François; Ingels, Alexandre; Galiano, Marc; Sanchez-Salas, Rafael; Barret, Eric; Cathelineau, Xavier

    2017-01-01

    Focal cryotherapy emerged as an efficient option to treat favorable and localized prostate cancer (PCa). The purpose of this video is to describe the procedure step by step. We present the case of a 68 year-old man with localized PCa in the anterior aspect of the prostate. The procedure is performed under general anesthesia, with the patient in lithotomy position. Briefly, the equipament utilized includes the cryotherapy console coupled with an ultrasound system, argon and helium gas bottles, cryoprobes, temperature probes and an urethral warming catheter. The procedure starts with a real-time trans-rectal prostate ultrasound, which is used to outline the prostate, the urethra and the rectal wall. The cryoprobes are pretested and placed in to the prostate through the perineum, following a grid template, along with the temperature sensors under ultrasound guidance. A cystoscopy confirms the right positioning of the needles and the urethral warming catheter is installed. Thereafter, the freeze sequence with argon gas is started, achieving extremely low temperatures (-40ºC) to induce tumor cell lysis. Sequentially, the thawing cycle is performed using helium gas. This process is repeated one time. Results among several series showed a biochemical disease-free survival between 71-93% at 9-70 month- follow-up, incontinence rates between 0-3.6% and erectile dysfunction between 0-42% (1-5). Focal cryotherapy is a feasible procedure to treat anterior PCa that may offer minimal morbidity, allowing good cancer control and better functional outcomes when compared to whole-gland treatment. Copyright® by the International Brazilian Journal of Urology.

  2. Focal cryotherapy: step by step technique description

    Directory of Open Access Journals (Sweden)

    Cristina Redondo

    Full Text Available ABSTRACT Introduction and objective: Focal cryotherapy emerged as an efficient option to treat favorable and localized prostate cancer (PCa. The purpose of this video is to describe the procedure step by step. Materials and methods: We present the case of a 68 year-old man with localized PCa in the anterior aspect of the prostate. Results: The procedure is performed under general anesthesia, with the patient in lithotomy position. Briefly, the equipment utilized includes the cryotherapy console coupled with an ultrasound system, argon and helium gas bottles, cryoprobes, temperature probes and an urethral warming catheter. The procedure starts with a real-time trans-rectal prostate ultrasound, which is used to outline the prostate, the urethra and the rectal wall. The cryoprobes are pretested and placed in to the prostate through the perineum, following a grid template, along with the temperature sensors under ultrasound guidance. A cystoscopy confirms the right positioning of the needles and the urethral warming catheter is installed. Thereafter, the freeze sequence with argon gas is started, achieving extremely low temperatures (-40°C to induce tumor cell lysis. Sequentially, the thawing cycle is performed using helium gas. This process is repeated one time. Results among several series showed a biochemical disease-free survival between 71-93% at 9-70 month- follow-up, incontinence rates between 0-3.6% and erectile dysfunction between 0-42% (1–5. Conclusions: Focal cryotherapy is a feasible procedure to treat anterior PCa that may offer minimal morbidity, allowing good cancer control and better functional outcomes when compared to whole-gland treatment.

  3. Steps towards an evolutionary physics

    CERN Document Server

    Tiezzi, E

    2006-01-01

    If thermodynamics is to physics as logic is to philosophy, recent theoretical advancements lend new coherence to the marvel and dynamism of life on Earth. Enzo Tiezzi's "Steps Towards an Evolutionary Physics" is a primer and guide, to those who would to stand on the shoulders of giants to attain this view: Heisenberg, Planck, Bateson, Varela, and Prigogine as well as notable contemporary scientists. The adventure of such a free and enquiring spirit thrives not so much on answers as on new questions. The book offers a new gestalt on the uncertainty principle and concept of probability. A wide range of examples, enigmas, and paradoxes lead one's imagination on an exquisite dance. Among the applications are: songs and shapes of nature, oscillatory reactions, orientors, goal functions and configurations of processes, and "dissipative structures and the city". Ecodynamics is a new science, which proposes a cross-fertilization between Charles Darwin and Ilya Prigogine. As an enigma in thermodynamics, Entropy forms ...

  4. Nuclear reactions

    International Nuclear Information System (INIS)

    Lane, A.M.

    1980-01-01

    In reviewing work at Harwell over the past 25 years on nuclear reactions it is stated that a balance has to be struck in both experiment and theory between work on cross-sections of direct practical relevance to reactors and on those relevant to an overall understanding of reaction processes. The compound nucleus and direct process reactions are described. Having listed the contributions from AERE, Harwell to developments in nuclear reaction research in the period, work on the optical model, neutron capture theory, reactions at doorway states with fine structure, and sum-rules for spectroscopic factors are considered in more detail. (UK)

  5. Transfer effects of step training on stepping performance in untrained directions in older adults: A randomized controlled trial.

    Science.gov (United States)

    Okubo, Yoshiro; Menant, Jasmine; Udyavar, Manasa; Brodie, Matthew A; Barry, Benjamin K; Lord, Stephen R; L Sturnieks, Daina

    2017-05-01

    Although step training improves the ability of quick stepping, some home-based step training systems train limited stepping directions and may cause harm by reducing stepping performance in untrained directions. This study examines the possible transfer effects of step training on stepping performance in untrained directions in older people. Fifty four older adults were randomized into: forward step training (FT); lateral plus forward step training (FLT); or no training (NT) groups. FT and FLT participants undertook a 15-min training session involving 200 step repetitions. Prior to and post training, choice stepping reaction time and stepping kinematics in untrained, diagonal and lateral directions were assessed. Significant interactions of group and time (pre/post-assessment) were evident for the first step after training indicating negative (delayed response time) and positive (faster peak stepping speed) transfer effects in the diagonal direction in the FT group. However, when the second to the fifth steps after training were included in the analysis, there were no significant interactions of group and time for measures in the diagonal stepping direction. Step training only in the forward direction improved stepping speed but may acutely slow response times in the untrained diagonal direction. However, this acute effect appears to dissipate after a few repeated step trials. Step training in both forward and lateral directions appears to induce no negative transfer effects in diagonal stepping. These findings suggest home-based step training systems present low risk of harm through negative transfer effects in untrained stepping directions. ANZCTR 369066. Copyright © 2017 Elsevier B.V. All rights reserved.

  6. Reaction engineering of urea alcoholysis: Alkyl carbamates

    OpenAIRE

    Mote, Dhananjay R.; Ranade, Vivek V.

    2017-01-01

    Urea alcoholysis is a reversible reaction generating alkyl carbamate and ammonia as products. The reaction can be performed non-catalytically or in presence of catalyst. The first step in Reaction engineering analysis is to finalize the reactor configuration. In this case it is important to determine the necessity of reactive separation (simultaneous reaction and separation). This has been addressed by first establishing the reversibility of the reaction through theoretical and experimental i...

  7. Site selectivity of specific reaction steps important for catalysis

    DEFF Research Database (Denmark)

    Nielsen, Kenneth

    that it was possible to shift the CO TPD behavior of dierent systems. It was showed that for the Ru(0 1 54) sample it was possible to shift the TPD shape from the single crystal type to the nano-particle type by sputtering the sample for 300 s. It was also showed that for a system consisting of a PVD nano-particle lm...... it was possible to shift its TPD behavior from the nano-particle type to the single crystal type by annealing it for 600 s at 900 K. In the Bi/Pt(111) side project samples was prepared by PVD of bismuth on a Pt(111) single crystal, after which the sample was subjected to successively increasing heat treatments...

  8. Ion-Molecule Reaction Dynamics.

    Science.gov (United States)

    Meyer, Jennifer; Wester, Roland

    2017-05-05

    We review the recent advances in the investigation of the dynamics of ion-molecule reactions. During the past decade, the combination of single-collision experiments in crossed ion and neutral beams with the velocity map ion imaging detection technique has enabled a wealth of studies on ion-molecule reactions. These methods, in combination with chemical dynamics simulations, have uncovered new and unexpected reaction mechanisms, such as the roundabout mechanism and the subtle influence of the leaving group in anion-molecule nucleophilic substitution reactions. For this important class of reactions, as well as for many fundamental cation-molecule reactions, the information obtained with crossed-beam imaging is discussed. The first steps toward understanding micro-solvation of ion-molecule reaction dynamics are presented. We conclude with the presentation of several interesting directions for future research.

  9. Biodiesel production from microalgae Spirulina maxima by two step process: Optimization of process variable

    Directory of Open Access Journals (Sweden)

    M.A. Rahman

    2017-04-01

    Full Text Available Biodiesel from green energy source is gaining tremendous attention for ecofriendly and economically aspect. In this investigation, a two-step process was developed for the production of biodiesel from microalgae Spirulina maxima and determined best operating conditions for the steps. In the first stage, acid esterification was conducted to lessen acid value (AV from 10.66 to 0.51 mgKOH/g of the feedstock and optimal conditions for maximum esterified oil yielding were found at molar ratio 12:1, temperature 60°C, 1% (wt% H2SO4, and mixing intensity 400 rpm for a reaction time of 90 min. The second stage alkali transesterification was carried out for maximum biodiesel yielding (86.1% and optimal conditions were found at molar ratio 9:1, temperature 65°C, mixing intensity 600 rpm, catalyst concentration 0.75% (wt% KOH for a reaction time of 20 min. Biodiesel were analyzed according to ASTM standards and results were within standards limit. Results will helpful to produce third generation algal biodiesel from microalgae Spirulina maxima in an efficient manner.

  10. Learning SQL in Steps

    Directory of Open Access Journals (Sweden)

    Philip Garner

    2015-08-01

    Full Text Available Learning SQL is a common problem for many Computer Science (CS students, the steps involved are quite different to those mastered when learning procedural or object-oriented programming languages. The introduction of commercial products that include shortcuts into the learning environment can initially appear to benefit the student, however, transferring these skills to a textual environment can be difficult for many students. Computer Science students are required to build textual SQL queries because the demands of complex queries can quickly out grow the capabilities of graphical query builders available in many software packages. SQL in Steps (SiS is a graphical user interface centred around the textual translation of a query; this combination of a GUI and a clear representation of its textual meaning has the potential to improve the way in which users gain an understanding of SQL. SiS allows for an incremental and evolutionary development of queries by enabling students to build queries step by step until their goal is reached. A planned evaluation of SiS hopes to quantify the extent to which the introduction of such a user interface into the learning environment can improve the students' understanding of the language.

  11. Queen Mary Two Step

    OpenAIRE

    Melin, Mats H.

    2007-01-01

    n/a Dance devised by Mats Melin in October 2007 whilst teaching Ceilidh dancing on board the cruise ship Queen Mary 2 crossing the Atlantic from Southampton to New York and back with the Ian Muir Sound from Prestwick. The segment of music featured is from Ian Muir Scottish Dance Band's recording of an Eva Three step.

  12. Stepping in the river

    Directory of Open Access Journals (Sweden)

    Julie Kearney

    2016-11-01

    Full Text Available 'Stepping in the River' is about the cultural misunderstandings and small betrayals that arise when First World tourists visit Third World countries. It is also about the enduring love that people in these countries can inspire, imperfect though that love may be.

  13. Step-Change

    NARCIS (Netherlands)

    Babah Daouda, Falylath; Ingenbleek, P.T.M.; Trijp, van H.C.M.

    2016-01-01

    With upcoming middle classes in Africa, micro-entrepreneurs witness new opportunities that can potentially lift them out of poverty. Exploiting these opportunities requires entrepreneurs to make a ‘step-change’ away from the bottom of the pyramid to middle-class markets. This process hosts

  14. Enantioselective solvent-free Robinson annulation reactions

    Indian Academy of Sciences (India)

    Unknown

    The use of proline or any other amino acid in asymmetric annulation reactions in a solid–liquid phase reaction in the absence of solvents to effect an asymmetric synthesis is an important step forward towards cleaner synthesis 2. ... Reports on solvent-free reactions have become increasingly frequent and the field has.

  15. Method of controlling fusion reaction rates

    Science.gov (United States)

    Kulsrud, Russell M.; Furth, Harold P.; Valeo, Ernest J.; Goldhaber, Maurice

    1988-01-01

    A method of controlling the reaction rates of the fuel atoms in a fusion reactor comprises the step of polarizing the nuclei of the fuel atoms in a particular direction relative to the plasma confining magnetic field. Fusion reaction rates can be increased or decreased, and the direction of emission of the reaction products can be controlled, depending on the choice of polarization direction.

  16. Linear step drive

    International Nuclear Information System (INIS)

    Haniger, L.; Elger, R.; Kocandrle, L.; Zdebor, J.

    1986-01-01

    A linear step drive is described developed in Czechoslovak-Soviet cooperation and intended for driving WWER-1000 control rods. The functional principle is explained of the motor and the mechanical and electrical parts of the drive, power control, and the indicator of position are described. The motor has latches situated in the reactor at a distance of 3 m from magnetic armatures, it has a low structural height above the reactor cover, which suggests its suitability for seismic localities. Its magnetic circuits use counterpoles; the mechanical shocks at the completion of each step are damped using special design features. The position indicator is of a special design and evaluates motor position within ±1% of total travel. A drive diagram and the flow chart of both the control electronics and the position indicator are presented. (author) 4 figs

  17. Stepping Stone Mobility.

    OpenAIRE

    Jovanovic, B.; Nyarko, Y.

    1996-01-01

    People at the top of an occupational ladder earn more partly because they have spent time on lower rungs, where they have learned something. But what precisely do they learn? There are two contrasting views: First, the Bandit model assumes that people are different, that experience reveals their characteristics, and that consequently an occupational switch can result. Second, in our Stepping Stone model, experience raises a worker's productivity on a given task and the acquired skill can in p...

  18. Learning SQL in Steps

    OpenAIRE

    Philip Garner; John Mariani

    2015-01-01

    Learning SQL is a common problem for many Computer Science (CS) students, the steps involved are quite different to those mastered when learning procedural or object-oriented programming languages. The introduction of commercial products that include shortcuts into the learning environment can initially appear to benefit the student, however, transferring these skills to a textual environment can be difficult for many students. Computer Science students are required to build textual SQL queri...

  19. Three steps ahead

    OpenAIRE

    Heller, Yuval

    2012-01-01

    We study a variant of the repeated Prisoner's Dilemma with uncertain horizon, in which each player chooses his foresight ability: that is, the timing in which he is informed about the realized length of the interaction. In addition, each player has an independent probability to observe the opponent's foresight ability. We show that if this probability is not too close to zero or one, then the game admits an evolutionarily stable strategy, in which agents who look one step ahead and agents who...

  20. Multistep processes in nuclear reactions

    International Nuclear Information System (INIS)

    Hodgson, P.E.

    1988-01-01

    The theories of nuclear reactions are reviewed with particular attention to the recent work on multistep processes. The evidence for compound nucleus and direct interaction reactions is described together with the results of comparisons between theories and experimental data. These theories have now proved inadequate, and there is evidence for multistep processes that take place after the initial direct stage but long before the attainment of the statistical equilibrium characteristic of compound nucleus processes. The theories of these reactions are described and it is shown how they can account for the experimental data and thus give a comprehensive understanding of nuclear reactions. (author)

  1. Compensatory stepping responses in individuals with stroke: a pilot study.

    Science.gov (United States)

    Lakhani, Bimal; Mansfield, Avril; Inness, Elizabeth L; McIlroy, William E

    2011-05-01

    Impaired postural control and a high incidence of falls are commonly observed following stroke. Compensatory stepping responses are critical to reactive balance control. We hypothesize that, following a stroke, individuals with unilateral limb dyscontrol will be faced with the unique challenge of controlling such rapid stepping reactions that may eventually be linked to the high rate of falling. The objectives of this exploratory pilot study were to investigate compensatory stepping in individuals poststroke with regard to: (1) choice of initial stepping limb (paretic or non-paretic); (2) step characteristics; and (3) differences in step characteristics when the initial step is taken with the paretic vs. the non-paretic limb. Four subjects following stroke (38-165 days post) and 11 healthy young adults were recruited. Anterior and posterior perturbations were delivered by using a weight drop system. Force plates recorded centre-of-pressure excursion prior to the onset of stepping and step timing. Of the four subjects, three only attempted to step with their non-paretic limb and one stepped with either limb. Time to foot-off was generally slow, whereas step onset time and swing time were comparable to healthy controls. Two of the four subjects executed multistep responses in every trial, and attempts to force stepping with the paretic limb were unsuccessful in three of the four subjects. Despite high clinical balance scores, these individuals with stroke demonstrated impaired compensatory stepping responses, suggesting that current clinical evaluations might not accurately reflect reactive balance control in this population.

  2. Comparative analysis of single-step and two-step biodiesel production using supercritical methanol on laboratory-scale

    International Nuclear Information System (INIS)

    Micic, Radoslav D.; Tomić, Milan D.; Kiss, Ferenc E.; Martinovic, Ferenc L.; Simikić, Mirko Ð.; Molnar, Tibor T.

    2016-01-01

    Highlights: • Single-step supercritical transesterification compared to the two-step process. • Two-step process: oil hydrolysis and subsequent supercritical methyl esterification. • Experiments were conducted in a laboratory-scale batch reactor. • Higher biodiesel yields in two-step process at milder reaction conditions. • Two-step process has potential to be cost-competitive with the single-step process. - Abstract: Single-step supercritical transesterification and two-step biodiesel production process consisting of oil hydrolysis and subsequent supercritical methyl esterification were studied and compared. For this purpose, comparative experiments were conducted in a laboratory-scale batch reactor and optimal reaction conditions (temperature, pressure, molar ratio and time) were determined. Results indicate that in comparison to a single-step transesterification, methyl esterification (second step of the two-step process) produces higher biodiesel yields (95 wt% vs. 91 wt%) at lower temperatures (270 °C vs. 350 °C), pressures (8 MPa vs. 12 MPa) and methanol to oil molar ratios (1:20 vs. 1:42). This can be explained by the fact that the reaction system consisting of free fatty acid (FFA) and methanol achieves supercritical condition at milder reaction conditions. Furthermore, the dissolved FFA increases the acidity of supercritical methanol and acts as an acid catalyst that increases the reaction rate. There is a direct correlation between FFA content of the product obtained in hydrolysis and biodiesel yields in methyl esterification. Therefore, the reaction parameters of hydrolysis were optimized to yield the highest FFA content at 12 MPa, 250 °C and 1:20 oil to water molar ratio. Results of direct material and energy costs comparison suggest that the process based on the two-step reaction has the potential to be cost-competitive with the process based on single-step supercritical transesterification. Higher biodiesel yields, similar or lower energy

  3. SYSTEMATIZATION OF THE BASIC STEPS OF THE STEP-AEROBICS

    Directory of Open Access Journals (Sweden)

    Darinka Korovljev

    2011-03-01

    Full Text Available Following the development of the powerful sport industry, in front of us appeared a lot of new opportunities for creating of the new programmes of exercising with certain requisites. One of such programmes is certainly step-aerobics. Step-aerobics can be defined as a type of aerobics consisting of the basic aerobic steps (basic steps applied in exercising on stepper (step bench, with a possibility to regulate its height. Step-aerobics itself can be divided into several groups, depending on the following: type of music, working methods and adopted knowledge of the attendants. In this work, the systematization of the basic steps in step-aerobics was made on the basis of the following criteria: steps origin, number of leg motions in stepping and relating the body support at the end of the step. Systematization of the basic steps of the step-aerobics is quite significant for making a concrete review of the existing basic steps, thus making creation of the step-aerobics lesson easier

  4. Stepping Stones through Time

    Directory of Open Access Journals (Sweden)

    Emily Lyle

    2012-03-01

    Full Text Available Indo-European mythology is known only through written records but it needs to be understood in terms of the preliterate oral-cultural context in which it was rooted. It is proposed that this world was conceptually organized through a memory-capsule consisting of the current generation and the three before it, and that there was a system of alternate generations with each generation taking a step into the future under the leadership of a white or red king.

  5. Implementing a stepped-care approach in primary care: results of a qualitative study

    Directory of Open Access Journals (Sweden)

    Franx Gerdien

    2012-01-01

    Full Text Available Abstract Background Since 2004, 'stepped-care models' have been adopted in several international evidence-based clinical guidelines to guide clinicians in the organisation of depression care. To enhance the adoption of this new treatment approach, a Quality Improvement Collaborative (QIC was initiated in the Netherlands. Methods Alongside the QIC, an intervention study using a controlled before-and-after design was performed. Part of the study was a process evaluation, utilizing semi-structured group interviews, to provide insight into the perceptions of the participating clinicians on the implementation of stepped care for depression into their daily routines. Participants were primary care clinicians, specialist clinicians, and other healthcare staff from eight regions in the Netherlands. Analysis was supported by the Normalisation Process Theory (NPT. Results The introduction of a stepped-care model for depression to primary care teams within the context of a depression QIC was generally well received by participating clinicians. All three elements of the proposed stepped-care model (patient differentiation, stepped-care treatment, and outcome monitoring, were translated and introduced locally. Clinicians reported changes in terms of learning how to differentiate between patient groups and different levels of care, changing antidepressant prescribing routines as a consequence of having a broader treatment package to offer to their patients, and better working relationships with patients and colleagues. A complex range of factors influenced the implementation process. Facilitating factors were the stepped-care model itself, the structured team meetings (part of the QIC method, and the positive reaction from patients to stepped care. The differing views of depression and depression care within multidisciplinary health teams, lack of resources, and poor information systems hindered the rapid introduction of the stepped-care model. The NPT

  6. SPAR-H Step-by-Step Guidance

    Energy Technology Data Exchange (ETDEWEB)

    W. J. Galyean; A. M. Whaley; D. L. Kelly; R. L. Boring

    2011-05-01

    This guide provides step-by-step guidance on the use of the SPAR-H method for quantifying Human Failure Events (HFEs). This guide is intended to be used with the worksheets provided in: 'The SPAR-H Human Reliability Analysis Method,' NUREG/CR-6883, dated August 2005. Each step in the process of producing a Human Error Probability (HEP) is discussed. These steps are: Step-1, Categorizing the HFE as Diagnosis and/or Action; Step-2, Rate the Performance Shaping Factors; Step-3, Calculate PSF-Modified HEP; Step-4, Accounting for Dependence, and; Step-5, Minimum Value Cutoff. The discussions on dependence are extensive and include an appendix that describes insights obtained from the psychology literature.

  7. The nuclear reaction matrix

    International Nuclear Information System (INIS)

    Krenciglowa, E.M.; Kung, C.L.; Kuo, T.T.S.; Osnes, E.; and Department of Physics, State University of New York at Stony Brook, Stony Brook, New York 11794)

    1976-01-01

    Different definitions of the reaction matrix G appropriate to the calculation of nuclear structure are reviewed and discussed. Qualitative physical arguments are presented in support of a two-step calculation of the G-matrix for finite nuclei. In the first step the high-energy excitations are included using orthogonalized plane-wave intermediate states, and in the second step the low-energy excitations are added in, using harmonic oscillator intermediate states. Accurate calculations of G-matrix elements for nuclear structure calculations in the Aapprox. =18 region are performed following this procedure and treating the Pauli exclusion operator Q 2 /sub p/ by the method of Tsai and Kuo. The treatment of Q 2 /sub p/, the effect of the intermediate-state spectrum and the energy dependence of the reaction matrix are investigated in detail. The present matrix elements are compared with various matrix elements given in the literature. In particular, close agreement is obtained with the matrix elements calculated by Kuo and Brown using approximate methods

  8. Nuclear reaction matrix

    International Nuclear Information System (INIS)

    Krenciglowa, E.M.; Kung, C.L.; Kuo, T.T.S.; Osnes, E.

    1975-01-01

    Different definitions of the reaction matrix G appropriate to the calculation of nuclear structure are reviewed and discussed. Qualitative physical arguments are presented in support of a two-step calculation of the G-matrix for finite nuclei. In the first step the high-energy excitations are included using orthogonalized plane-wave intermediate states, and in the second step the low-energy excitations are added in, using harmonic oscillator intermediate states. Accurate calculations of G-matrix elements for nuclear structure calculations in the A approximately 18 region are performed following this procedure and treating the Pauli exclusion operator Q/sub 2p/ by the method of Tsai and Kuo. The treatment of Q/sub 2p/, the effect of the intermediate-state spectrum and the energy dependence of the reaction matrix are investigated in detail. The present matrix elements are compared with various matrix elements given in the literature. In particular, close argument is obtained with the matrix elements calculated by Kuo and Brown using approximate methods

  9. Understanding cancer staging

    Science.gov (United States)

    ... detailed information about the cancer stage. TNM Staging System The most common system for staging cancer in the form of solid tumor is the TNM system. Most providers and cancer centers use it to stage ...

  10. Optimizing Chemical Reactions with Deep Reinforcement Learning.

    Science.gov (United States)

    Zhou, Zhenpeng; Li, Xiaocheng; Zare, Richard N

    2017-12-27

    Deep reinforcement learning was employed to optimize chemical reactions. Our model iteratively records the results of a chemical reaction and chooses new experimental conditions to improve the reaction outcome. This model outperformed a state-of-the-art blackbox optimization algorithm by using 71% fewer steps on both simulations and real reactions. Furthermore, we introduced an efficient exploration strategy by drawing the reaction conditions from certain probability distributions, which resulted in an improvement on regret from 0.062 to 0.039 compared with a deterministic policy. Combining the efficient exploration policy with accelerated microdroplet reactions, optimal reaction conditions were determined in 30 min for the four reactions considered, and a better understanding of the factors that control microdroplet reactions was reached. Moreover, our model showed a better performance after training on reactions with similar or even dissimilar underlying mechanisms, which demonstrates its learning ability.

  11. Hippocampus discovery First steps

    Directory of Open Access Journals (Sweden)

    Eliasz Engelhardt

    Full Text Available The first steps of the discovery, and the main discoverers, of the hippocampus are outlined. Arantius was the first to describe a structure he named "hippocampus" or "white silkworm". Despite numerous controversies and alternate designations, the term hippocampus has prevailed until this day as the most widely used term. Duvernoy provided an illustration of the hippocampus and surrounding structures, considered the first by most authors, which appeared more than one and a half century after Arantius' description. Some authors have identified other drawings and texts which they claim predate Duvernoy's depiction, in studies by Vesalius, Varolio, Willis, and Eustachio, albeit unconvincingly. Considering the definition of the hippocampal formation as comprising the hippocampus proper, dentate gyrus and subiculum, Arantius and Duvernoy apparently described the gross anatomy of this complex. The pioneering studies of Arantius and Duvernoy revealed a relatively small hidden formation that would become one of the most valued brain structures.

  12. Astronomical sketching a step-by-step introduction

    CERN Document Server

    Handy, Richard; Perez, Jeremy; Rix, Erika; Robbins, Sol

    2007-01-01

    This book presents the amateur with fine examples of astronomical sketches and step-by-step tutorials in each medium, from pencil to computer graphics programs. This unique book can teach almost anyone to create beautiful sketches of celestial objects.

  13. Bio-inspired step-climbing in a hexapod robot.

    Science.gov (United States)

    Chou, Ya-Cheng; Yu, Wei-Shun; Huang, Ke-Jung; Lin, Pei-Chun

    2012-09-01

    Inspired by the observation that the cockroach changes from a tripod gait to a different gait for climbing high steps, we report on the design and implementation of a novel, fully autonomous step-climbing maneuver, which enables a RHex-style hexapod robot to reliably climb a step up to 230% higher than the length of its leg. Similar to the climbing strategy most used by cockroaches, the proposed maneuver is composed of two stages. The first stage is the 'rearing stage,' inclining the body so the front side of the body is raised and it is easier for the front legs to catch the top of the step, followed by the 'rising stage,' maneuvering the body's center of mass to the top of the step. Two infrared range sensors are installed on the front of the robot to detect the presence of the step and its orientation relative to the robot's heading, so that the robot can perform automatic gait transition, from walking to step-climbing, as well as correct its initial tilt approaching posture. An inclinometer is utilized to measure body inclination and to compute step height, thus enabling the robot to adjust its gait automatically, in real time, and to climb steps of different heights and depths successfully. The algorithm is applicable for the robot to climb various rectangular obstacles, including a narrow bar, a bar and a step (i.e. a bar of infinite width). The performance of the algorithm is evaluated experimentally, and the comparison of climbing strategies and climbing behaviors in biological and robotic systems is discussed.

  14. Bio-inspired step-climbing in a hexapod robot

    International Nuclear Information System (INIS)

    Chou, Ya-Cheng; Yu, Wei-Shun; Huang, Ke-Jung; Lin, Pei-Chun

    2012-01-01

    Inspired by the observation that the cockroach changes from a tripod gait to a different gait for climbing high steps, we report on the design and implementation of a novel, fully autonomous step-climbing maneuver, which enables a RHex-style hexapod robot to reliably climb a step up to 230% higher than the length of its leg. Similar to the climbing strategy most used by cockroaches, the proposed maneuver is composed of two stages. The first stage is the ‘rearing stage,’ inclining the body so the front side of the body is raised and it is easier for the front legs to catch the top of the step, followed by the ‘rising stage,’ maneuvering the body's center of mass to the top of the step. Two infrared range sensors are installed on the front of the robot to detect the presence of the step and its orientation relative to the robot's heading, so that the robot can perform automatic gait transition, from walking to step-climbing, as well as correct its initial tilt approaching posture. An inclinometer is utilized to measure body inclination and to compute step height, thus enabling the robot to adjust its gait automatically, in real time, and to climb steps of different heights and depths successfully. The algorithm is applicable for the robot to climb various rectangular obstacles, including a narrow bar, a bar and a step (i.e. a bar of infinite width). The performance of the algorithm is evaluated experimentally, and the comparison of climbing strategies and climbing behaviors in biological and robotic systems is discussed. (paper)

  15. Reaction mechanisms

    International Nuclear Information System (INIS)

    Nguyen Trong Anh

    1988-01-01

    The 1988 progress report of the Reaction Mechanisms laboratory (Polytechnic School, France), is presented. The research topics are: the valence bond methods, the radical chemistry, the modelling of the transition states by applying geometric constraints, the long range interactions (ion - molecule) in gaseous phase, the reaction sites in gaseous phase and the mass spectroscopy applications. The points of convergence between the investigations of the mass spectroscopy and the theoretical chemistry teams, as well as the purposes guiding the research programs, are discussed. The published papers, the conferences, the congress communications and the thesis, are also reported [fr

  16. Capture reactions

    NARCIS (Netherlands)

    Endt, P.M.

    1956-01-01

    Capture reactions will be considered here from the viewpoint of the nuclear spectroscopist. Especially important to him are the capture of neutrons, protons, and alpha particles, which may proceed through narrow resonances, offering a well defined initial state for the subsequent deexcitation

  17. Allergic reactions

    Science.gov (United States)

    ... that don't bother most people (such as venom from bee stings and certain foods, medicines, and pollens) can ... person. If the allergic reaction is from a bee sting, scrape the ... more venom. If the person has emergency allergy medicine on ...

  18. cycloaddition reactions

    Indian Academy of Sciences (India)

    Unknown

    ... has shown very severe limitations in predicting the regioselectivity. In comparison,. DFT-based descriptors are better suited to model the regioselectivity of cycloaddition reactions. Acknowledgements. GG thanks the Council of Scientific and Industrial. Research for a fellowship. References. 1. Winkler J D 1996 Chem. Rev.

  19. One-step microlithography

    Science.gov (United States)

    Kahlen, Franz-Josef; Sankaranarayanan, Srikanth; Kar, Aravinda

    1997-09-01

    Subject of this investigation is a one-step rapid machining process to create miniaturized 3D parts, using the original sample material. An experimental setup where metal powder is fed to the laser beam-material interaction region has been built. The powder is melted and forms planar, 2D geometries as the substrate is moved under the laser beam in XY- direction. After completing the geometry in the plane, the substrate is displaced in Z-direction, and a new layer of material is placed on top of the just completed deposit. By continuous repetition of this process, 3D parts wee created. In particular, the impact of the focal spot size of the high power laser beam on the smallest achievable structures was investigated. At a translation speed of 51 mm/s a minimum material thickness of 590 micrometers was achieved. Also, it was shown that a small Z-displacement has a negligible influence on the continuity of the material deposition over this power range. A high power CO2 laser was used as energy source, the material powder under investigation was stainless steel SS304L. Helium was used as shield gas at a flow rate of 15 1/min. The incident CO2 laser beam power was varied between 300 W and 400 W, with the laser beam intensity distribute in a donut mode. The laser beam was focused to a focal diameter of 600 (Mu) m.

  20. Utilization of Fenton-like reaction for antibiotics and resistant bacteria elimination in different parts of WWTP.

    Science.gov (United States)

    Mackuľak, Tomáš; Nagyová, Kristína; Faberová, Milota; Grabic, Roman; Koba, Olga; Gál, Miroslav; Birošová, Lucia

    2015-09-01

    Utilization of relatively low-cost modification of Fenton reaction for the elimination of selected antibiotics and resistant coliforms in different part of wastewater treatment plant (WWTP) was studied. The concentration of antibiotics and occurrence of resistant gems in different stages of WWTP in the capital city of Slovakia - Bratislava was analyzed by LC-MS/MS technique. Consequently, Fenton-like reaction was applied for the elimination of chemical and biological contaminants. Comparative study with classical Fenton reaction was also done. Very high concentrations of clarithromycin, ciprofloxacin and azithromycin in influent water were found. Coliform bacteria were predominantly resistant to ampicillin, ciprofloxacin and gentamicin. After the mechanical stage, the concentration of antibiotics in water was significantly decreased because of the sorption during this step. Biological step degraded 12 types of antibiotics. Analyses of effluent water showed very bad elimination of azithromycin (919ng/L) and clarithromycin (684ng/L). Contrary, ciprofloxacin was removed with very high efficiency (95%). The number of resistant bacteria was also significantly decreased in effluent water. In the case of Escherichia coli only ampicillin and gentamicin resistance bacteria were detected. Our results show that antibiotics as well as resistant bacteria were eliminated by the modification of classical Fenton reaction with high efficiency. The modification of the Fenton reaction can decrease the process wages, environmental impact. Moreover, the degradation process was easily controlled, monitored and tuned. Copyright © 2015 Elsevier B.V. All rights reserved.

  1. Topics in heavy ion reactions

    International Nuclear Information System (INIS)

    Feshbach, H.

    1980-01-01

    Methods are discussed which, by straightforward extensions of currently available concepts and procedures, can be used for the description of reactions induced by heavy ions. The first section describes a nuclear Weiszaecker-Williams method for peripheral collisions of nuclei which is here extended to pion production in peripheral collisions. The second section emphasizes the relationship between the collision of an energetic proton and that of an energetic heavy ion with a nucleus. The comparatively remarkable behavior of the observed energy dependence of the angular distribution and average energy of the fragments produced in proton collision is described and a qualitative explanation offered. The third section is concerned with the'pre-equilibrium' reactions as well as the multi-step direct reactions which are known to play an important role in heavy ion collisions. A statistical theory of multi-step direct and multi-step compound reactions providing explicit expressions for the energy and angular distributions is formulated. A diffusion equation in momentum space is obtained as an approximation to these formulas. The extension of these results to heavy ion reactions in which phenomena involving deformation, mass and charge transfer and multi-particle final states are important, is made. (author)

  2. Domino reaction based approach for the synthesis of novel molecules

    Indian Academy of Sciences (India)

    admin

    The ability to create complex molecules in only a few steps has long been the dream of chemists. With the development of domino reactions, it has become more viable. A domino reaction can be defined as the reaction in which several bonds are formed in one sequence without isolating intermediates, changing reaction ...

  3. SPAR-H Step-by-Step Guidance

    Energy Technology Data Exchange (ETDEWEB)

    April M. Whaley; Dana L. Kelly; Ronald L. Boring; William J. Galyean

    2012-06-01

    Step-by-step guidance was developed recently at Idaho National Laboratory for the US Nuclear Regulatory Commission on the use of the Standardized Plant Analysis Risk-Human Reliability Analysis (SPAR-H) method for quantifying Human Failure Events (HFEs). This work was done to address SPAR-H user needs, specifically requests for additional guidance on the proper application of various aspects of the methodology. This paper overviews the steps of the SPAR-H analysis process and highlights some of the most important insights gained during the development of the step-by-step directions. This supplemental guidance for analysts is applicable when plant-specific information is available, and goes beyond the general guidance provided in existing SPAR-H documentation. The steps highlighted in this paper are: Step-1, Categorizing the HFE as Diagnosis and/or Action; Step-2, Rate the Performance Shaping Factors; Step-3, Calculate PSF-Modified HEP; Step-4, Accounting for Dependence, and; Step-5, Minimum Value Cutoff.

  4. C—C bond formation in the intramolecular Diels-Alder reaction of triene amides

    Directory of Open Access Journals (Sweden)

    Abdelilah Benallou

    2018-02-01

    Full Text Available The mechanism nature of the intramolecular Diels–Alder reaction has been performed; and thus, the changes of C—C bond forming/breaking along IRC are characterized in this study. Conceptual DFT analyses of the most favorable adduct fused/exo shows that the flux electronic will take place from diene to dienophile moiety. Moreover, ELF topological analysis based on the electron density predicts that C—C bond is formed by the coupling of two pseudoradical centers generated at the most significant atoms of the molecules. However, C2 vs C3, also C1 and C4 interaction comes mainly from the global electron density transfer which takes place along the reaction. Two- stage one-step is the proposed mechanism of this reaction, the first stage aims for the formation of C2—C3 σ bond while the second stage aims for C1—C4 σ bond formation. Interestingly, the observed asynchronicity of this IMDA reaction due principally to the asymmetric reorganization of electron density at the most attractive centers.

  5. Steps towards silicon optoelectronics

    Energy Technology Data Exchange (ETDEWEB)

    Starovoytov, A

    1999-07-01

    This thesis addresses the issue of a potential future microelectronics technology, namely the possibility of utilising the optical properties of nanocrystalline silicon for optoelectronic circuits. The subject is subdivided into three chapters. Chapter 1 is an introduction. It formulates the oncoming problem for microelectronic development, explains the basics of Integrated Optoelectronics, introduces porous silicon as a new light-emitting material and gives a brief review of other competing light-emitting material systems currently under investigation. Examples of existing porous silicon devices are given. Chapter 2 reviews the basic physics relevant to the subject of this thesis and in-forms on the present situation in this field of research, including both experimental and theoretical knowledge gained up-to-date. The chapter provides the necessary background for correct interpretation of the results reported in Chapter 3 and for a realistic decision on the direction for future work. Chapter 3 describes my own experimental and computational results within the framework of the subject, obtained at De Montfort University. These include: one-step preparation of laterally structured porous silicon with photoluminescence and microscopy characterisation, Raman spectroscopy of porous silicon, a polarisation study of the photoluminescence from porous silicon, computer simulations of the conductivity of two-component media and of laser focused atomic deposition for nanostructure fabrication. Thus, this thesis makes a dual contribution to the chosen field: it summarises the present knowledge on the possibility of utilising optical properties of nanocrystalline silicon in silicon-based electronics, and it reports new results within the framework of the subject. The main conclusion is that due to its promising optoelectronic properties nanocrystalline silicon remains a prospective competitor for the cheapest and fastest microelectronics of the next century. (author)

  6. A sensitive trimethylamine-N-oxide aldolase assay in two steps without deproteinisation

    DEFF Research Database (Denmark)

    Nielsen, Michael Krogsgaard; Havemeister, W.; Rehbein, H.

    2000-01-01

    A two-step assay for trimethylamine-N-oxide aldolase (the target enzyme) is described in which the second step, the indicator reaction, is of the enzymatic end-point type. This indicator reaction is carried out at a slightly alkaline pH, outside the target enzyme's active pH range. An effective...

  7. Morphological characteristics of waste polyethylene/polypropylene plastics during pyrolysis and representative morphological signal characterizing pyrolysis stages.

    Science.gov (United States)

    Wang, H; Chen, D; Yuan, G; Ma, X; Dai, X

    2013-02-01

    In this work, the morphological characteristics of waste polyethylene (PE)/polypropylene (PP) plastics during their pyrolysis process were investigated, and based on their basic image changing patterns representative morphological signals describing the pyrolysis stages were obtained. PE and PP granules and films were used as typical plastics for testing, and influence of impurities was also investigated. During pyrolysis experiments, photographs of the testing samples were taken sequentially with a high-speed infrared camera, and the quantitative parameters that describe the morphological characteristics of these photographs were explored using the "Image Pro Plus (v6.3)" digital image processing software. The experimental results showed that plastics pyrolysis involved four stages: melting, two stages of decomposition which are characterized with bubble formation caused by volatile evaporating, and ash deposition; and each stage was characterized with its own phase changing behaviors and morphological features. Two stages of decomposition are the key step of pyrolysis since they took up half or more of the reaction time; melting step consumed another half of reaction time in experiments when raw materials were heated up from ambient temperatures; and coke-like deposition appeared as a result of decomposition completion. Two morphological signals defined from digital image processing, namely, pixel area of the interested reaction region and bubble ratio (BR) caused by volatile evaporating were found to change regularly with pyrolysis stages. In particular, for all experimental scenarios with plastics films and granules, the BR curves always exhibited a slowly drop as melting started and then a sharp increase followed by a deep decrease corresponding to the first stage of intense decomposition, afterwards a second increase - drop section corresponding to the second stage of decomposition appeared. As ash deposition happened, the BR dropped to zero or very low

  8. Direct NO decomposition over stepped transition-metal surfaces

    DEFF Research Database (Denmark)

    Falsig, Hanne; Bligaard, Thomas; Christensen, Claus H.

    2007-01-01

    We establish the full potential energy diagram for the direct NO decomposition reaction over stepped transition-metal surfaces by combining a database of adsorption energies on stepped metal surfaces with known Bronsted-Evans-Polanyi (BEP) relations for the activation barriers of dissociation...... of diatomic molecules over stepped transition- and noble-metal surfaces. The potential energy diagram directly points to why Pd and Pt are the best direct NO decomposition catalysts among the 3d, 4d, and 5d metals. We analyze the NO decomposition reaction in terms of a Sabatier-Gibbs-type analysis, and we...... demonstrate that this type of analysis yields results that to within a surprisingly small margin of error are directly proportional to the measured direct NO decomposition over Ru, Rh, Pt, Pd, Ag, and An. We suggest that Pd, which is a better catalyst than Pt under the employed reaction conditions...

  9. Prostate cancer staging

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000397.htm Prostate cancer staging To use the sharing features on this ... trials you may be able to join How Prostate Cancer Staging is Done Initial staging is based on ...

  10. Batch and flow photochemical benzannulations based on the reaction of ynamides and diazo ketones. Application to the synthesis of polycyclic aromatic and heteroaromatic compounds.

    Science.gov (United States)

    Willumstad, Thomas P; Haze, Olesya; Mak, Xiao Yin; Lam, Tin Yiu; Wang, Yu-Pu; Danheiser, Rick L

    2013-11-15

    Highly substituted polycyclic aromatic and heteroaromatic compounds are produced via a two-stage tandem benzannulation/cyclization strategy. The initial benzannulation step proceeds via a pericyclic cascade mechanism triggered by thermal or photochemical Wolff rearrangement of a diazo ketone. The photochemical process can be performed using a continuous flow reactor which facilitates carrying out reactions on a large scale and minimizes the time required for photolysis. Carbomethoxy ynamides as well as more ketenophilic bis-silyl ynamines and N-sulfonyl and N-phosphoryl ynamides serve as the reaction partner in the benzannulation step. In the second stage of the strategy, RCM generates benzofused nitrogen heterocycles, and various heterocyclization processes furnish highly substituted and polycyclic indoles of types that were not available by using the previous cyclobutenone-based version of the tandem strategy.

  11. Pathway design using de novo steps through uncharted biochemical spaces.

    Science.gov (United States)

    Kumar, Akhil; Wang, Lin; Ng, Chiam Yu; Maranas, Costas D

    2018-01-12

    Existing retrosynthesis tools generally traverse production routes from a source to a sink metabolite using known enzymes or de novo steps. Generally, important considerations such as blending known transformations with putative steps, complexity of pathway topology, mass conservation, cofactor balance, thermodynamic feasibility, microbial chassis selection, and cost are largely dealt with in a posteriori fashion. The computational procedure we present here designs bioconversion routes while simultaneously considering any combination of the aforementioned design criteria. First, we track and codify as rules all reaction centers using a prime factorization-based encoding technique (rePrime). Reaction rules and known biotransformations are then simultaneously used by the pathway design algorithm (novoStoic) to trace both metabolites and molecular moieties through balanced bio-conversion strategies. We demonstrate the use of novoStoic in bypassing steps in existing pathways through putative transformations, assembling complex pathways blending both known and putative steps toward pharmaceuticals, and postulating ways to biodegrade xenobiotics.

  12. High-yield production of vanillin from ferulic acid by a coenzyme-independent decarboxylase/oxygenase two-stage process.

    Science.gov (United States)

    Furuya, Toshiki; Miura, Misa; Kuroiwa, Mari; Kino, Kuniki

    2015-05-25

    Vanillin is one of the world's most important flavor and fragrance compounds in foods and cosmetics. Recently, we demonstrated that vanillin could be produced from ferulic acid via 4-vinylguaiacol in a coenzyme-independent manner using the decarboxylase Fdc and the oxygenase Cso2. In this study, we investigated a new two-pot bioprocess for vanillin production using the whole-cell catalyst of Escherichia coli expressing Fdc in the first stage and that of E. coli expressing Cso2 in the second stage. We first optimized the second-step Cso2 reaction from 4-vinylguaiacol to vanillin, a rate-determining step for the production of vanillin. Addition of FeCl2 to the cultivation medium enhanced the activity of the resulting E. coli cells expressing Cso2, an iron protein belonging to the carotenoid cleavage oxygenase family. Furthermore, a butyl acetate-water biphasic system was effective in improving the production of vanillin. Under the optimized conditions, we attempted to produce vanillin from ferulic acid by a two-pot bioprocess on a flask scale. In the first stage, E. coli cells expressing Fdc rapidly decarboxylated ferulic acid and completely converted 75 mM of this substrate to 4-vinylguaiacol within 2 h at pH 9.0. After the first-stage reaction, cells were removed from the reaction mixture by centrifugation, and the pH of the resulting supernatant was adjusted to 10.5, the optimal pH for Cso2. This solution was subjected to the second-stage reaction. In the second stage, E. coli cells expressing Cso2 efficiently oxidized 4-vinylguaiacol to vanillin. The concentration of vanillin reached 52 mM (7.8 g L(-1)) in 24 h, which is the highest level attained to date for the biotechnological production of vanillin using recombinant cells. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Enantioselective solvent-free Robinson annulation reactions

    Indian Academy of Sciences (India)

    Unknown

    asymmetric annulation reactions in a solid–liquid phase reaction in the absence of solvents to effect an asymmetric synthesis is an important step forward towards cleaner synthesis 2. Environmental and economic pressures are now forcing the chemical community to search for more efficient ways of performing chemical ...

  14. Strategies for Innovation in Multicomponent Reaction Design

    OpenAIRE

    Ganem, Bruce

    2009-01-01

    By generating structural complexity in a single step from three or more reactants, multicomponent reactions (MCRs) make it possible to synthesize target compounds with greater efficiency and atom economy. The history of such reactions can be traced to the mid-nineteenth century when Strecker first produced α-aminonitriles from the condensation of aldehydes with ammonia and hydrogen cyanide.

  15. Hydrazine in the Ugi Tetrazole Reaction

    NARCIS (Netherlands)

    Patil, Pravin; Zhang, Ji; Kurpiewska, Katarzyna; Kalinowska-Tłuścik, Justyna; Dömling, Alexander

    2016-01-01

    We describe the hitherto unknown use of N-Boc-protected hydrazine in the Ugi tetrazole reaction to access a library of highly substituted 5-(hydrazinomethyl)-1-methyl-1H-tetrazoles. The reaction is very versatile and good to high yielding. A one-pot, two-step procedure is given.

  16. The host cell sulfonation pathway contributes to retroviral infection at a step coincident with provirus establishment.

    Science.gov (United States)

    Bruce, James W; Ahlquist, Paul; Young, John A T

    2008-11-01

    The early steps of retrovirus replication leading up to provirus establishment are highly dependent on cellular processes and represent a time when the virus is particularly vulnerable to antivirals and host defense mechanisms. However, the roles played by cellular factors are only partially understood. To identify cellular processes that participate in these critical steps, we employed a high volume screening of insertionally mutagenized somatic cells using a murine leukemia virus (MLV) vector. This approach identified a role for 3'-phosphoadenosine 5'-phosphosulfate synthase 1 (PAPSS1), one of two enzymes that synthesize PAPS, the high energy sulfate donor used in all sulfonation reactions catalyzed by cellular sulfotransferases. The role of the cellular sulfonation pathway was confirmed using chemical inhibitors of PAPS synthases and cellular sulfotransferases. The requirement for sulfonation was mapped to a stage during or shortly after MLV provirus establishment and influenced subsequent gene expression from the viral long terminal repeat (LTR) promoter. Infection of cells by an HIV vector was also shown to be highly dependent on the cellular sulfonation pathway. These studies have uncovered a heretofore unknown regulatory step of retroviral replication, have defined a new biological function for sulfonation in nuclear gene expression, and provide a potentially valuable new target for HIV/AIDS therapy.

  17. The host cell sulfonation pathway contributes to retroviral infection at a step coincident with provirus establishment.

    Directory of Open Access Journals (Sweden)

    James W Bruce

    2008-11-01

    Full Text Available The early steps of retrovirus replication leading up to provirus establishment are highly dependent on cellular processes and represent a time when the virus is particularly vulnerable to antivirals and host defense mechanisms. However, the roles played by cellular factors are only partially understood. To identify cellular processes that participate in these critical steps, we employed a high volume screening of insertionally mutagenized somatic cells using a murine leukemia virus (MLV vector. This approach identified a role for 3'-phosphoadenosine 5'-phosphosulfate synthase 1 (PAPSS1, one of two enzymes that synthesize PAPS, the high energy sulfate donor used in all sulfonation reactions catalyzed by cellular sulfotransferases. The role of the cellular sulfonation pathway was confirmed using chemical inhibitors of PAPS synthases and cellular sulfotransferases. The requirement for sulfonation was mapped to a stage during or shortly after MLV provirus establishment and influenced subsequent gene expression from the viral long terminal repeat (LTR promoter. Infection of cells by an HIV vector was also shown to be highly dependent on the cellular sulfonation pathway. These studies have uncovered a heretofore unknown regulatory step of retroviral replication, have defined a new biological function for sulfonation in nuclear gene expression, and provide a potentially valuable new target for HIV/AIDS therapy.

  18. Accessory stimulus modulates executive function during stepping task.

    Science.gov (United States)

    Watanabe, Tatsunori; Koyama, Soichiro; Tanabe, Shigeo; Nojima, Ippei

    2015-07-01

    When multiple sensory modalities are simultaneously presented, reaction time can be reduced while interference enlarges. The purpose of this research was to examine the effects of task-irrelevant acoustic accessory stimuli simultaneously presented with visual imperative stimuli on executive function during stepping. Executive functions were assessed by analyzing temporal events and errors in the initial weight transfer of the postural responses prior to a step (anticipatory postural adjustment errors). Eleven healthy young adults stepped forward in response to a visual stimulus. We applied a choice reaction time task and the Simon task, which consisted of congruent and incongruent conditions. Accessory stimuli were randomly presented with the visual stimuli. Compared with trials without accessory stimuli, the anticipatory postural adjustment error rates were higher in trials with accessory stimuli in the incongruent condition and the reaction times were shorter in trials with accessory stimuli in all the task conditions. Analyses after division of trials according to whether anticipatory postural adjustment error occurred or not revealed that the reaction times of trials with anticipatory postural adjustment errors were reduced more than those of trials without anticipatory postural adjustment errors in the incongruent condition. These results suggest that accessory stimuli modulate the initial motor programming of stepping by lowering decision threshold and exclusively under spatial incompatibility facilitate automatic response activation. The present findings advance the knowledge of intersensory judgment processes during stepping and may aid in the development of intervention and evaluation tools for individuals at risk of falls. Copyright © 2015 the American Physiological Society.

  19. Spallation reactions

    International Nuclear Information System (INIS)

    Cugon, J.

    1996-01-01

    Spallation reactions dominate the interactions of hadrons with nuclei in the GeV range (from ∼ 0.1 to ∼ 10 GeV). They correspond to a sometimes important ejection of light particles leaving most of the time a residue of mass commensurate with the target mass. The main features of the experimental data are briefly reviewed. The most successful theoretical model, namely the intranuclear cascade + evaporation model, is presented. Its physical content, results and possible improvements are critically discussed. Alternative approaches are shortly reviewed. (author)

  20. Analysis of kinetic reaction mechanisms

    CERN Document Server

    Turányi, Tamás

    2014-01-01

    Chemical processes in many fields of science and technology, including combustion, atmospheric chemistry, environmental modelling, process engineering, and systems biology, can be described by detailed reaction mechanisms consisting of numerous reaction steps. This book describes methods for the analysis of reaction mechanisms that are applicable in all these fields. Topics addressed include: how sensitivity and uncertainty analyses allow the calculation of the overall uncertainty of simulation results and the identification of the most important input parameters, the ways in which mechanisms can be reduced without losing important kinetic and dynamic detail, and the application of reduced models for more accurate engineering optimizations. This monograph is invaluable for researchers and engineers dealing with detailed reaction mechanisms, but is also useful for graduate students of related courses in chemistry, mechanical engineering, energy and environmental science and biology.

  1. HTSC-Josephson step contacts

    International Nuclear Information System (INIS)

    Herrmann, K.

    1994-03-01

    In this work the properties of josephson step contacts are investigated. After a short introduction into Josephson step contacts the structure, properties and the Josphson contacts of YBa 2 Cu 3 O 7-x high-T c superconductors is presented. The fabrication of HTSC step contacts and the microstructure is discussed. The electric properties of these contacts are measured together with the Josephson emission and the magnetic field dependence. The temperature dependence of the stationary transport properties is given. (WL)

  2. Nuclear reactions

    International Nuclear Information System (INIS)

    Corner, J.; Richardson, K.; Fenton, N.

    1990-01-01

    Nuclear reactions' marks a new development in the study of television as an agency of public policy debate. During the Eighties, nuclear energy became a major international issue. The disasters at Three-mile Island and Chernobyl created a global anxiety about its risks and a new sensitivity to it among politicians and journalists. This book is a case-study into documentary depictions of nuclear energy in television and video programmes and into the interpretations and responses of viewers drawn from many different occupational groupings. How are the complex and specialist arguments about benefit, risk and proof conveyed through the different conventions of commentary, interview and film sequence? What symbolic associations does the visual language of television bring to portrayals of the issue? And how do viewers make sense of various and conflicting accounts, connecting what they see and hear on the screen with their pre-existing knowledge, experience and 'civic' expectations. The authors examine some of the contrasting forms and themes which have been used by programme makers to explain and persuade, and then give a sustained analysis of the nature and sources of viewers' own accounts. 'Nuclear Reactions' inquires into the public meanings surrounding energy and the environment, spelling out in its conclusion some of the implications for future media treatments of this issue. It is also a key contribution to the international literature on 'television knowledge' and the processes of active viewing. (author)

  3. Between Stage and Screen

    NARCIS (Netherlands)

    Tornqvist, Egil

    1996-01-01

    Ingmar Bergman is worldwide known as a film and stage director. Yet no-one has attempted to compare his stage and screen activities. In Between stage and screen Egil Tornqvist examines formal and thematical correspondences and differences between a number of Bergman's stage, screen, and radio

  4. Reaction rates for reaction-diffusion kinetics on unstructured meshes.

    Science.gov (United States)

    Hellander, Stefan; Petzold, Linda

    2017-02-14

    The reaction-diffusion master equation is a stochastic model often utilized in the study of biochemical reaction networks in living cells. It is applied when the spatial distribution of molecules is important to the dynamics of the system. A viable approach to resolve the complex geometry of cells accurately is to discretize space with an unstructured mesh. Diffusion is modeled as discrete jumps between nodes on the mesh, and the diffusion jump rates can be obtained through a discretization of the diffusion equation on the mesh. Reactions can occur when molecules occupy the same voxel. In this paper, we develop a method for computing accurate reaction rates between molecules occupying the same voxel in an unstructured mesh. For large voxels, these rates are known to be well approximated by the reaction rates derived by Collins and Kimball, but as the mesh is refined, no analytical expression for the rates exists. We reduce the problem of computing accurate reaction rates to a pure preprocessing step, depending only on the mesh and not on the model parameters, and we devise an efficient numerical scheme to estimate them to high accuracy. We show in several numerical examples that as we refine the mesh, the results obtained with the reaction-diffusion master equation approach those of a more fine-grained Smoluchowski particle-tracking model.

  5. Grief: Difficult Times, Simple Steps.

    Science.gov (United States)

    Waszak, Emily Lane

    This guide presents techniques to assist others in coping with the loss of a loved one. Using the language of 9 layperson, the book contains more than 100 tips for caregivers or loved ones. A simple step is presented on each page, followed by reasons and instructions for each step. Chapters include: "What to Say"; "Helpful Things to Do"; "Dealing…

  6. Carbonitriding reactions of diatomaceous earth: phase evolution and reaction mechanisms

    Directory of Open Access Journals (Sweden)

    BRANKO MATOVIC

    2006-06-01

    Full Text Available The possibility of using diatomaceous earth as Si precursor for low temperature synthesis of non-oxide powders by carbothermal reduction-nitridation was studied. It was found that carbonitriding reactions produce phases of the Si–Al–O–N system. Already at 1300 °C, nanosized, non-oxide powders were obtained. The comparatively low reaction temperatures is attributred to the nano-porous nature of the raw material. The evolution of crystalline phases proceeded via many intermediate stages. The powders were characterized by X-ray and SEM investigations. The results showed that diatomaceous earth can be a very effective source for obtaining non-oxide powders.

  7. Microprocessor controller for stepping motors

    International Nuclear Information System (INIS)

    Strait, B.G.; Thuot, M.E.

    1977-01-01

    A new concept for digital computer control of multiple stepping motors which operate in a severe electromagnetic pulse environment is presented. The motors position mirrors in the beam-alignment system of a 100-kJ CO 2 laser. An asynchronous communications channel of a computer is used to send coded messages, containing the motor address and stepping-command information, to the stepping-motor controller in a bit serial format over a fiber-optics communications link. The addressed controller responds by transmitting to the computer its address and other motor information, thus confirming the received message. Each controller is capable of controlling three stepping motors. The controller contains the fiber-optics interface, a microprocessor, and the stepping-motor driven circuits. The microprocessor program, which resides in an EPROM, decodes the received messages, transmits responses, performs the stepping-motor sequence logic, maintains motor-position information, and monitors the motor's reference switch. For multiple stepping-motor application, the controllers are connected in a daisy chain providing control of many motors from one asynchronous communications channel of the computer

  8. Chain reaction

    International Nuclear Information System (INIS)

    Balogh, Brian.

    1991-01-01

    Chain Reaction is a work of recent American political history. It seeks to explain how and why America came to depend so heavily on its experts after World War II, how those experts translated that authority into political clout, and why that authority and political discretion declined in the 1970s. The author's research into the internal memoranda of the Atomic Energy Commission substantiates his argument in historical detail. It was not the ravages of American anti-intellectualism, as so many scholars have argued, that brought the experts back down to earth. Rather, their decline can be traced to the very roots of their success after World War II. The need to over-state anticipated results in order to garner public support, incessant professional and bureaucratic specialization, and the sheer proliferation of expertise pushed arcane and insulated debates between experts into public forums at the same time that a broad cross section of political participants found it easier to gain access to their own expertise. These tendencies ultimately undermined the political influence of all experts. (author)

  9. Resident reactions to staging Tour de Taiwan 2012: Comparison of ...

    African Journals Online (AJOL)

    An impact scale, which comprised of 22 items, was developed based on four factors: general perceptions, community coherence and development, image enhancement and tourism benefits and disadvantages. Host residents differed significantly in the perceptions of event impacts based on different geographical areas.

  10. Diastereoselective Ugi reaction of chiral 1,3-aminoalcohols derived from an organocatalytic Mannich reaction.

    Science.gov (United States)

    Caputo, Samantha; Basso, Andrea; Moni, Lisa; Riva, Renata; Rocca, Valeria; Banfi, Luca

    2016-01-01

    Enantiomerically pure β-aminoalcohols, produced through an organocatalytic Mannich reaction, were subjected to an Ugi multicomponent reaction under classical or Lewis acid-promoted conditions with diastereoselectivities ranging from moderate to good. This approach represents a step-economical path to enantiomerically pure, polyfunctionalized peptidomimetics endowed with three stereogenic centers, allowing the introduction of five diversity inputs.

  11. Diastereoselective Ugi reaction of chiral 1,3-aminoalcohols derived from an organocatalytic Mannich reaction

    OpenAIRE

    Caputo, Samantha; Basso, Andrea; Moni, Lisa; Riva, Renata; Rocca, Valeria; Banfi, Luca

    2016-01-01

    Summary Enantiomerically pure ?-aminoalcohols, produced through an organocatalytic Mannich reaction, were subjected to an Ugi multicomponent reaction under classical or Lewis acid-promoted conditions with diastereoselectivities ranging from moderate to good. This approach represents a step-economical path to enantiomerically pure, polyfunctionalized peptidomimetics endowed with three stereogenic centers, allowing the introduction of five diversity inputs.

  12. Diastereoselective Ugi reaction of chiral 1,3-aminoalcohols derived from an organocatalytic Mannich reaction

    Directory of Open Access Journals (Sweden)

    Samantha Caputo

    2016-01-01

    Full Text Available Enantiomerically pure β-aminoalcohols, produced through an organocatalytic Mannich reaction, were subjected to an Ugi multicomponent reaction under classical or Lewis acid-promoted conditions with diastereoselectivities ranging from moderate to good. This approach represents a step-economical path to enantiomerically pure, polyfunctionalized peptidomimetics endowed with three stereogenic centers, allowing the introduction of five diversity inputs.

  13. Breast cancer staging

    Science.gov (United States)

    ... this page: //medlineplus.gov/ency/patientinstructions/000911.htm Breast cancer staging To use the sharing features on this ... Once your health care team knows you have breast cancer , they will do more tests to stage it. ...

  14. Seven Stages of Alzheimer's

    Science.gov (United States)

    ... Dementias . Learn more: Daily Care and Behaviors Severe Alzheimer's disease (late-stage) Get support Late-stage care decisions can be some of the hardest families face. Connect with other caregivers who have been through the process on our ...

  15. Stages of Adolescence

    Science.gov (United States)

    ... Español Text Size Email Print Share Stages of Adolescence Page Content Article Body Adolescence, these years from puberty to adulthood, may be roughly divided into three stages: early adolescence, generally ages eleven to fourteen; middle adolescence, ages ...

  16. A two-step enzymatic resolution process for large-scale production of (S)- and (R)-ethyl-3-hydroxybutyrate.

    Science.gov (United States)

    Fishman, A; Eroshov, M; Dee-Noor, S S; van Mil, J; Cogan, U; Effenberger, R

    2001-08-05

    An efficient two-step enzymatic process for production of (R)- and (S)-ethyl-3-hydroxybutyrate (HEB), two important chiral intermediates for the pharmaceutical market, was developed and scaled-up to a multikilogram scale. Both enantiomers were obtained at 99% chemical purity and over 96% enantiomeric excess, with a total process yield of 73%. The first reaction involved a solvent-free acetylation of racemic HEB with vinylacetate for the production of (S)-HEB. In the second reaction, (R)-enriched ethyl-3-acetoxybutyrate (AEB) was subjected to alcoholysis with ethanol to derive optically pure (R)-HEB. Immobilized Candida antarctica lipase B (CALB) was employed in both stages, with high productivity and selectivity. The type of butyric acid ester influenced the enantioselectivity of the enzyme. Thus, extending the ester alkyl chain from ethyl to octyl resulted in a decrease in enantiomeric excess, whereas using bulky groups such as benzyl or t-butyl, improved the enantioselectivity of the enzyme. A stirred reactor was found unsuitable for large-scale production due to attrition of the enzyme particles and, therefore, a batchwise loop reactor system was used for bench-scale production. The immobilized enzyme was confined to a column and the reactants were circulated through the enzyme bed until the targeted conversion was reached. The desired products were separated from the reaction mixture in each of the two stages by fractional distillation. The main features of the process are the exclusion of solvent (thus ensuring high process throughput), and the use of the same enzyme for both the acetylation and the alcoholysis steps. Kilogram quantities of (S)-HEB and (R)-HEB were effectively prepared using this unit, which can be easily scaled-up to produce industrial quantities. Copyright 2001 John Wiley & Sons, Inc.

  17. Kinetic aspects of the Maillard reaction: a critical review

    NARCIS (Netherlands)

    Boekel, van M.A.J.S.

    2001-01-01

    The literature concerning the kinetics of the Maillard reaction was critically discussed according to the initial, intermediate and advanced stages, as this is the way the Maillard reaction is traditionally analysed. For each stage, a division is made between simple kinetics and complex kinetics.

  18. Step 1: Learn about Diabetes

    Science.gov (United States)

    ... JavaScript on. Feature: Type 2 Diabetes Step 1: Learn About Diabetes Past Issues / Fall 2014 Table of ... fewer problems with your eyesight, feet, and gums. Learn how caring for your diabetes helps you feel ...

  19. NextSTEP-2 Habitation

    Data.gov (United States)

    National Aeronautics and Space Administration — Through the public-private partnerships enabled by the Next Space Technologies for Exploration Partnerships - 2 (NextSTEP-2) Broad Agency Announcement, NASA has...

  20. 7 Steps to Aging Well

    Science.gov (United States)

    ... Issue Past Issues Special Section 7 Steps to Aging Well Past Issues / Winter 2007 Table of Contents ... Exercise: A Guide from the National Institute on Aging is a publication from NIA that has strength, ...

  1. nonlinear kinetics and mechanism of nile blue reaction

    African Journals Online (AJOL)

    Prof. S.B. Jonnalagadda

    A 11-step mechanism, consistent with the overall reaction dynamics and supported by simulations, is ... been designed based on the chemistry of BZ reactions, the role of bromide ion under various concentration ... dynamics of nile blue - acidic bromate reaction arises from the extremely slow depletion rate of nile blue in the ...

  2. A computational study of pyrolysis reactions of lignin model compounds

    Science.gov (United States)

    Thomas Elder

    2010-01-01

    Enthalpies of reaction for the initial steps in the pyrolysis of lignin have been evaluated at the CBS-4m level of theory using fully substituted b-O-4 dilignols. Values for competing unimolecular decomposition reactions are consistent with results previously published for phenethyl phenyl ether models, but with lowered selectivity. Chain propagating reactions of free...

  3. Beyond Erikson's Eight Stages.

    Science.gov (United States)

    Whitney, Ruth

    1979-01-01

    Erik Erikson has described eight stages of the healthy personality. This essay offers a revised version of the eight stages. Although most individuals develop through the eight stages, each is personally unique because patterns of fluctuation between safety and growth differ from one individual to another. (Author)

  4. Cervical Cancer Stage IIIA

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IIIA Add to My Pictures View /Download : ... 1275x1275 View Download Large: 2550x2550 View Download Title: Cervical Cancer Stage IIIA Description: Stage IIIA cervical cancer; drawing ...

  5. Cervical Cancer Stage IVA

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IVA Add to My Pictures View /Download : ... 1575x1200 View Download Large: 3150x2400 View Download Title: Cervical Cancer Stage IVA Description: Stage IVA cervical cancer; drawing ...

  6. Cervical Cancer Stage IVB

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IVB Add to My Pictures View /Download : ... 1200x1305 View Download Large: 2400x2610 View Download Title: Cervical Cancer Stage IVB Description: Stage IVB cervical cancer; drawing ...

  7. Cervical Cancer Stage IIIB

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IIIB Add to My Pictures View /Download : ... 1425x1326 View Download Large: 2850x2651 View Download Title: Cervical Cancer Stage IIIB Description: Stage IIIB cervical cancer; drawing ...

  8. Cervical Cancer Stage IB

    Science.gov (United States)

    ... hyphen, e.g. -historical Searches are case-insensitive Cervical Cancer Stage IB Add to My Pictures View /Download : ... 1613x1200 View Download Large: 3225x2400 View Download Title: Cervical Cancer Stage IB Description: Stage IB1 and IB2 cervical ...

  9. Cervical Cancer Stage IA

    Science.gov (United States)

    ... historical Searches are case-insensitive Cervical Cancer Stage IA Add to My Pictures View /Download : Small: 720x576 ... Large: 3000x2400 View Download Title: Cervical Cancer Stage IA Description: Stage IA1 and IA2 cervical cancer; drawing ...

  10. Predicting multiple step placements for human balance recovery tasks.

    Science.gov (United States)

    Aftab, Zohaib; Robert, Thomas; Wieber, Pierre-Brice

    2012-11-15

    Stepping is one of the predominant strategies to restore balance against an external perturbation. Although models have been proposed to estimate the recovery step placement for a given perturbation, they suffer from major limitations (step execution time usually neglected, no more than a single step recovery considered, etc.). The purpose of this study is to overcome these limitations and to develop a simple balance recovery model which can predict a complete multiple step recovery response. Inspired by the field of walking robots, we adapted a control scheme formerly proposed for biped robot locomotion. The scheme relies on a Linear Model Predictive Controller (LMPC) which estimates the best foot placements to zero the velocity of the Center of Mass (CoM), i.e. to reach a steady posture. The predicted step placements were compared against previously reported experimental data for tether-release conditions. They match correctly for various perturbation levels and both single step or multiple steps recovery. Although the current model still suffers from limitations (e.g., limited to the sagittal plane), these results demonstrate its ability to reproduce balance recovery reactions for different experimental scenarios. Copyright © 2012 Elsevier Ltd. All rights reserved.

  11. Redox reactions in food fermentations

    DEFF Research Database (Denmark)

    Hansen, Egon Bech

    2018-01-01

    Food fermentations are typically performed without actively supplying air. Except for possible surface microorganisms, oxygen will only be transiently available and the redox reactions during the fermentation need to be in balance. Production of ATP from fermentation of carbohydrates typically in...... of the redox properties of strains used to compose food cultures.......Food fermentations are typically performed without actively supplying air. Except for possible surface microorganisms, oxygen will only be transiently available and the redox reactions during the fermentation need to be in balance. Production of ATP from fermentation of carbohydrates typically...... involves oxidative steps in the early part of the pathways whereas a multitude of different reactions are used as compensating reductions. Much of the diversity seen between food fermentations arise from the different routes and the different electron acceptors used by microorganisms to counterbalance...

  12. Two Paired "Le Chatelier" Reactions

    Science.gov (United States)

    Cawley, John J.

    1995-07-01

    We have created a two-week, two hour-per-week cyclic experiment, which pairs two reactions. These reactions, the acid catalyzed esterification to yield n-amyl acetate and the base catalyzed hydrolysis of n-amyl acetate are intended to serve as a first and last experiment respectively, of the second-semester laboratory for liberal arts students. Because of time constraints, we have modified these experiments so that no distillation is performed as a purification step. The notion of achieving yields beyond the equilibrium value is discussed in terms of the pragmatics of removing one of the products of an equilibrium. Because of this "Le Chatelier" aspect of each reaction, each of them may be pushed in practicality to completion, which is well beyond the equilibrium value expectation. Because of the cycle, the chemistry may be done on a scale well beyond the microscale approach with little loss of material.

  13. Click-assembling triazole membrane on copper surface via one-step or two-steps and their corrosion inhibition performance

    Science.gov (United States)

    Wang, Yizhen; Yu, Yinzhe; Zhang, Jie; Gao, Lixin; Feng, Likui; Zhang, Daquan

    2018-01-01

    Triazole membrane was prepared on copper surface via one-step or two-steps click chemistry reaction of azide and alkyne compounds. Fourier transforms infrared spectroscopy (FT-IR) suggests the formation of triazole membrane on copper surface through both of one-step and two-steps click-assembling. The electrochemical results indicate that the protection efficiency of triazole click-assembling membrane forming via one-step is better than that for two-steps. The surface film on copper via one-step click-assembling is mainly composed of the triazole membrane. As for two-steps click-assembling, the triazole membrane is mainly produced in the defect of the alkyne inhibition film.

  14. Furfural production from rice husk using sulfuric acid and a solid acid catalyst through a two-stage process.

    Science.gov (United States)

    Ren, Suxia; Xu, Haiyan; Zhu, Jinling; Li, Shunqing; He, Xiaofeng; Lei, Tingzhou

    2012-10-01

    This study aimed to optimize the conditions for furfural production from rice husk via a two-stage process: acid hydrolysis followed by dehydration using an orthogonal test design and response surface methodology, respectively. Orthogonal test design was utilized in the hydrolysis step; optimum conditions were as follows: 2.5% sulfuric acid (mass fraction), 110°C reaction temperature, sulfuric acid to rice husk (L/S) ratio of 8 (g/mL), and a reaction time of 3h. According to the Box-Behnken design, the temperature, amount of catalyst, extractant volume, and reaction time were chosen as four important factors with three levels for the dehydration step. Conditions were further optimized by response surface analysis. The results showed that the optimal conditions were 177°C, 120 mL extractant volume, 2.1g of catalyst, and a reaction time of 4.8h. Under the optimal conditions, the furfural yield reached 8.9%, which is consistent with the estimated value, 8.97%. Copyright © 2012 Elsevier Ltd. All rights reserved.

  15. Cetuximab, Cisplatin, and Radiation Therapy in Treating Patients With Stage IB, Stage II, Stage III, or Stage IVA Cervical Cancer

    Science.gov (United States)

    2014-12-29

    Cervical Adenocarcinoma; Cervical Adenosquamous Carcinoma; Cervical Small Cell Carcinoma; Cervical Squamous Cell Carcinoma; Stage IB Cervical Cancer; Stage IIA Cervical Cancer; Stage IIB Cervical Cancer; Stage III Cervical Cancer; Stage IVA Cervical Cancer

  16. Microsoft Office SharePoint Designer 2007 Step by Step

    CERN Document Server

    Coventry, Penelope

    2008-01-01

    The smart way to learn Office SharePoint Designer 2007-one step at a time! Work at your own pace through the easy numbered steps, practice files on CD, helpful hints, and troubleshooting tips to master the fundamentals of building customized SharePoint sites and applications. You'll learn how to work with Windows® SharePoint Services 3.0 and Office SharePoint Server 2007 to create Web pages complete with Cascading Style Sheets, Lists, Libraries, and customized Web parts. Then, make your site really work for you by adding data sources, including databases, XML data and Web services, and RSS fe

  17. Information marketing business entrepreneur's step-by-step startup guide

    CERN Document Server

    magazine, Entrepreneur

    2012-01-01

    A six-figure income from information? Yes! It sounds easy because it is. You've got information that millions of others are looking for and now you can learn how to package, price and sell it.The experts at Entrepreneur take you step by step, jumpstarting your thinking about your area of expertise and showing you how to convert it into a high-demand information product. Following the example set by today's most successful information marketers, you learn the ins and outs of running your own information marketing business using proven strategies and effective marketing techniques.

  18. Microsoft Windows Sharepoint Services 3.0 Step by Step

    CERN Document Server

    Londer, Olga; Bleeker, Todd; Coventry, Penelope

    2007-01-01

    Experience learning made easy-and quickly teach yourself how to use Windows SharePoint Services to enable effective team collaboration. With Step By Step, you set the pace-building and practicing the skills you need, just when you need them! Build your own SharePoint site with easy-to-use templatesCreate lists and libraries to store informationAdd discussion boards, wikis, and blogsSet up Document and Meeting Workspaces for easy collaborationShare calendars, contacts, and data from Microsoft Office programsCustomize your pages with Web Parts Your all-in-one learning experience includes: Fi

  19. A step-by-step methodology for enterprise interoperability projects

    Science.gov (United States)

    Chalmeta, Ricardo; Pazos, Verónica

    2015-05-01

    Enterprise interoperability is one of the key factors for enhancing enterprise competitiveness. Achieving enterprise interoperability is an extremely complex process which involves different technological, human and organisational elements. In this paper we present a framework to help enterprise interoperability. The framework has been developed taking into account the three domains of interoperability: Enterprise Modelling, Architecture and Platform and Ontologies. The main novelty of the framework in comparison to existing ones is that it includes a step-by-step methodology that explains how to carry out an enterprise interoperability project taking into account different interoperability views, like business, process, human resources, technology, knowledge and semantics.

  20. Microsoft® Office Access™ 2007 Step by Step

    CERN Document Server

    Lambert, Steve; Lambert, Joan

    2009-01-01

    Experience learning made easy-and quickly teach yourself how to build database solutions with Access 2007. With Step By Step, you set the pace-building and practicing the skills you need, just when you need them! Build databases from scratch or from templatesExchange data with other databases and Office documentsCreate forms to simplify data entryUse filters and queries to find and analyze informationDesign rich reports that help make your data meaningfulHelp prevent data corruption and unauthorized access Your all-in-one learning experience includes: Files for building skills and practic

  1. Two-stage repair in hypospadias

    Directory of Open Access Journals (Sweden)

    K N Haxhirexha

    2008-01-01

    Full Text Available We provide the reader with a nonsystematic review concerning the use of the two-stage approach in hypospadias repairs. A one-stage approach using the tubularized incised plate urethroplasty is a well-standardized approach for the most cases of hypospadias. Nevertheless, in some primary severe cases, in most hypospadias failures and in selected patients with balanitis xerotica obliterans a two-stage approach is preferable. During the first stage the penis is straightened, if necessary and the urethral plate is substituted with a graft of either genital (prepuce or extragenital origin (oral mucosa or postauricular skin. During the second stage, performed around 6 months later, urethroplasty is accomplished by graft tubulization. Graft take is generally excellent, with only few cases requiring an additional inlay patch at second stage due to graft contracture. A staged approach allows for both excellent cosmetic results and a low morbidity including an overall 6% fistula rate and 2% stricture rate. Complications usually occur in the first year after the second stage and are higher in secondary repairs. Complications tend to decrease as experience increases and use of additional waterproofing layers contributes to reduce the fistula rate significantly. Long-term cosmetic results are excellent, but voiding and ejaculatory problems may occur in as much as 40% of cases if a long urethral tube is constructed. The procedure has a step learning curve but because of its technical simplicity does not require to be confined only to highly specialized centers.

  2. Decomposing properties of phosphogypsum with iron addition under two-step cycle multi-atmosphere control in fluidised bed.

    Science.gov (United States)

    Zheng, Dalong; Ma, Liping; Wang, Rongmou; Yang, Jie; Dai, Quxiu

    2018-02-01

    Phosphogypsum is a solid industry by-product generated when sulphuric acid is used to process phosphate ore into fertiliser. Phosphogypsum stacks without pretreatment are often piled on the land surface or dumped in the sea, causing significant environmental damage. This study examined the reaction characteristics of phosphogypsum, when decomposed in a multi-atmosphere fluidised bed. Phosphogypsum was first dried, sieved and mixed proportionally with lignite at the mass ratio of 10:1, it was then immersed in 0.8 [Formula: see text] with a solid-liquid ratio of 8:25. The study included a two-step cycle of multi-atmosphere control. First, a reducing atmosphere was provided to allow phosphogypsum decomposition through partial lignite combustion. After the reduction stage reaction was completed, the reducing atmosphere was changed into an air-support oxidising atmosphere at the constant temperature. Each atmosphere cycle had a conversion time of 30 min to ensure a sufficient reaction. The decomposing properties of phosphogypsum were obtained in different atmosphere cycles, at different reaction temperatures, different heating rates and different fluidised gas velocities, using experimental results combined with a theoretical analysis using FactSage 7.0 Reaction module. The study revealed that the optimum reaction condition was to circulate the atmosphere twice at a temperature of 1100 °C. The heating rate above 800 °C was 5 [Formula: see text], and the fluidised gas velocity was 0.40 [Formula: see text]. The procedure proposed in this article can serve as a phosphogypsum decomposition solution, and can support the future management of this by-product, resulting in more sustainable production.

  3. FIRST STEP towards ICF commercialization

    International Nuclear Information System (INIS)

    Saylor, W.W.; Pendergrass, J.H.; Dudziak, D.J.

    1984-01-01

    Production of tritium for weapons and fusion R and D programs and successful development of Inertial Confinement Fusion (ICF) technologies are important national goals. A conceptual design for an ICF facility to meet these goals is presented. FIRST STEP (Fusion, Inertial, Reduced-Requirements Systems Test for Special Nuclear Material, Tritium, and Energy Production) is a concept for a plant to produce SNM, tritium, and energy while serving as a test bed for ICF technology development. A credible conceptual design for an ICF SNM and tritium production facility that competes favorably with fission technology on the bases of cost, production quality, and safety was sought. FIRST STEP is also designed to be an engineering test facility that integrates systems required for an ICF power plant and that is intermediate in scale between proof-of-principle experiment and commercial power plant. FIRST STEP driver and pellet performance requirements are moderate and represent reasonable intermediate goals in an R and D plan for ICF commercialization. Repetition rate requirements for FIRST STEP are similar to those of commercial size plants and FIRST STEP can be used to integrate systems under realistic ICF conditions

  4. Fathers modify thermal reaction norms for hatching success in Atlantic cod, Gadus morhua

    DEFF Research Database (Denmark)

    Dahlke, Flemming T.; Politis, Sebastian Nikitas; Butts, Ian

    2016-01-01

    Climate-driven warming is altering marine ecosystems at an unprecedented rate and evolutionary adaptation may represent the last resort for many ectothermic organisms to avoid local extinction. The first step to elucidate the potential for adaptation to unfavorable thermal conditions is to assess...... the degree of genotype-based variation in thermal reaction norms of vital fitness traits. Marine broadcast spawning fishes experience extremely high rates ofmortality during early life stages. Paternally derived (genetic) variation underlying offspring fitness in adverse environmental conditions may...... therefore hold important implications for resilience. This study examined how males differ in their ability to sire viable offspring and whether the paternal contribution modified thermal reaction norms for hatching success in two replicated trials with cod Gadus morhua from the Northwest Atlantic (trial 1...

  5. Postnatal development of synchronous stepping in the gerbil (Gerbillus dasyurus).

    Science.gov (United States)

    Blumberg-Feldman, H; Eilam, D

    1995-02-01

    During the first two postnatal weeks, Wagner's gerbil (Gerbillus dasyurus) pups employed stepping sequences considered to be more basic than in the later stages of development and displayed alternate stepping of the legs in each girdle. In the third postnatal week, the adult mode of locomotion, the bound, became prominent and synchronous stepping dominated locomotion, gradually replacing alternate stepping. Motor performance of the gerbil pups corroborates previous studies in following a developmental motor gestalt termed 'warm-up', which involves an ordered incorporation of movements along three distinct spatial dimensions. In the present results, the validity of warm-up has been extended to a quantitative perspective: the order in which movement types reached their peak performance was identical to the order of their emergence in ontogeny. Transient modes of locomotion were also employed by gerbil pups during postnatal development, in accordance with changes in body morphology, indicating that there exists a causal link between body design and specific modes of locomotion.

  6. Storybridging: Four steps for constructing effective health narratives.

    Science.gov (United States)

    Boeijinga, Anniek; Hoeken, Hans; Sanders, José

    2017-12-01

    To develop a practical step-by-step approach to constructing narrative health interventions in response to the mixed results and wide diversity of narratives used in health-related narrative persuasion research. Development work was guided by essential narrative characteristics as well as principles enshrined in the Health Action Process Approach. The 'storybridging' method for constructing health narratives is described as consisting of four concrete steps: (a) identifying the stage of change, (b) identifying the key elements, (c) building the story, and (d) pre-testing the story. These steps are illustrated by means of a case study in which an effective narrative health intervention was developed for Dutch truck drivers: a high-risk, underprivileged occupational group. Although time and labour intensive, the Storybridging approach suggests integrating the target audience as an important stakeholder throughout the development process. Implications and recommendations are provided for health promotion targeting truck drivers specifically and for constructing narrative health interventions in general.

  7. Effect of heating on Maillard reactions in milk.

    NARCIS (Netherlands)

    Boekel, van M.A.J.S.

    1998-01-01

    Heated milk is subject to the Maillard reaction; lactose and lysine residues in milk proteins (mainly casein) are the reactants. An overview is given of the early, advanced and final stages of the Maillard reaction as it occurs in milk. The early Maillard reaction is confined to the formation of the

  8. Marketing dental implants: a step-by-step approach.

    Science.gov (United States)

    Schwab, D P

    1995-03-01

    Introducing dental implants into a practice requires planning and commitment. Part of the planning process is learning new clinical skills, but another essential component is developing a marketing approach. The author offers a seven-step plan for adding dental implants to your repertoire.

  9. Publishing Ethical Research: A Step-by-Step Overview

    Science.gov (United States)

    Wester, Kelly L.

    2011-01-01

    To publish ethical research, one must conduct research responsibly, making ethical choices from the inception of the research idea and throughout the research process. Conducting and publishing ethical research is important because of the impact the results will have on the counseling profession. Steps to consider are discussed.

  10. A clock reaction based on molybdenum blue.

    Science.gov (United States)

    Neuenschwander, Ulrich; Negron, Arnaldo; Jensen, Klavs F

    2013-05-30

    Clock reactions are rare kinetic phenomena, so far limited mostly to systems with ionic oxoacids and oxoanions in water. We report a new clock reaction in cyclohexanol that forms molybdenum blue from a noncharged, yellow molybdenum complex as precursor, in the presence of hydrogen peroxide. Interestingly, the concomitant color change is reversible, enabling multiple clock cycles to be executed consecutively. The kinetics of the clock reaction were experimentally characterized, and by adding insights from quantum chemical calculations, a plausible reaction mechanism was postulated. Key elementary reaction steps comprise sigmatropic rearrangements with five-membered or bicyclo[3.1.0] transition states. Importantly, numerical kinetic modeling demonstrated the mechanism's ability to reproduce the experimental findings. It also revealed that clock behavior is intimately connected to the sudden exhaustion of hydrogen peroxide. Due to the stoichiometric coproduction of ketone, the reaction bears potential for application in alcohol oxidation catalysis.

  11. Step by step male to female transsexual surgery.

    Science.gov (United States)

    da Silva, Rodrigo Uliano Moser; Abreu, Fernando Jahn da Silva; da Silva, Gabriel M V; Dos Santos, João Vitor Quadra Vieira; Batezini, Nelson Sivonei da Silva; Silva, Brasil; Rosito, Tiago Elias

    2018-01-01

    After the diagnosis of transsexualism is confirmed therapy commences with psychotherapeutic preparation for the conversion, and after conversion, long-term patient rehabilitation is maintained for at least two years. The indication for surgery is chronic discomfort caused by discord with the patient's natural gender, intense dislike of developing secondary sex characteristics and the onset of puberty. The surgical conversion of transsexuals is the main step in the complex care of these problematic patients (1). This surgery was first described by Benjamin H, using a flap of inverted penile skin (2) and is considered the gold standard since then. Male-to-female transsexual surgical techniques are well defined and give good cosmetic and functional results. Sex reassignment surgery promotes the improvement of psychological aspects and social relationships as shown in the World Health Organization Quality of Life Assessment applied in the patients submitted to this procedure (3). Techniques include the creation of a normal appearing female introitus, a vaginoplasty allowing sexual intercourse and the capability of clitoral orgasm (4). Various methods for neovaginoplasty have been described and can be classified into five categories, i.e. pedicled intestinal transplants, penile skin grafts, penile skin flaps, non-genital skin flaps and non-genital skin grafts (5). In our Hospital, we use penile and scrotal skin flaps. Until now, 174 procedures have been performed by our team using this technique with high rates of satisfaction (3). We present a step-by-step male to female transsexual surgery. Surgical gender reassignment of male transsexuals resulted in replicas of female genitalia which enabled coitus with orgasm (1). With this video we show step by step that a surgery using penile skin flaps is able to be performed with good cosmetic results. Copyright® by the International Brazilian Journal of Urology.

  12. Needed Computations Shortcutting Needed Steps

    DEFF Research Database (Denmark)

    Antoy, Sergio; Johannsen, Jacob; Libby, Steven

    We define a compilation scheme for a constructor-based strongly-sequential graph rewriting system which shortcuts some needed steps. The result of this compilation is another constructor-based graph rewriting system that is normalizing for the original system when using an innermost strategy. We...... then modify the resulting rewrite sytem in a way that avoids totally or partially the construction of the contracta of some needed steps of a computation. The resulting rewrite system can be easily implemented by eager functions in a variety of programming languages. When computing normal forms in this way...

  13. Multiple stage railgun

    International Nuclear Information System (INIS)

    Aaland, K.; Hawke, R.S.; Scudder, J.K.

    1982-01-01

    A multiple stage magnetic railgun accelerator for accelerating a projectile by movement of a plasma arc along the rails. The railgun is divided into a plurality of successive rail stages which are sequentially energized by separate energy sources as the projectile moves through the bore of the railgun. Propagation of energy from an energized rail stage back towards the breech end of the railgun can be prevented by connection of the energy sources to the rails through isolation diodes. Propagation of energy from an energized rail stage back towards the breech end of the railgun can also be prevented by dividing the rails into electrically isolated rail sections. In such case means are used to extinguish the arc at the end of each energized stage and a fuse or laser device is used to initiate a new plasma arc in the next energized rail stage

  14. Xylose Isomerization with Zeolites in a Two-Step Alcohol–Water Process

    DEFF Research Database (Denmark)

    Paniagua, Marta; Shunmugavel, Saravanamurugan; Melián Rodriguez, Mayra

    2015-01-01

    xyluloside (step 1) followed by hydrolysis after water addition to form additional xylulose (step 2). NMR spectroscopy studies performed with 13C-labeled xylose confirmed the proposed reaction pathway. The most active catalyst examined was zeolite Y, which proved more active than zeolite beta, ZSM-5......, and mordenite. The yield of xylulose obtained over H-USY (Si/Al=6) after 1 h of reaction at 1008C was 39%. After water hydrolysis in the second reaction step, the yield increased to 47%. Results obtained from pyridine adsorption studies confirm that H-USY (6) is a catalyst that combines Brønsted and Lewis acid......Isomerization of xylose to xylulose was efficiently catalyzed by large-pore zeolites in a two-step methanol–water process that enhanced the product yield significantly. The reaction pathway involves xylose isomerization to xylulose, which, in part, subsequently reacts with methanol to form methyl...

  15. on the elementary steps of acid zeolite catalyzed amination of light alcohols

    NARCIS (Netherlands)

    Veefkind, V.A.; Lercher, J.A.

    1999-01-01

    Potential elementary reaction steps in solid acid catalyzed amination of light alcohols are critically compared using hydrogen mordenite as (model) catalyst and the open mechanistic questions have been addressed. Transient kinetic experiments combined with in situ infrared spectroscopy and isotopic

  16. KAPSIES: A Program for the Calculation of Multi-Step Direct

    NARCIS (Netherlands)

    Koning, A.J.; Koning, A.J.; Akkermans, J.M.; Akkermans, J.M.

    1995-01-01

    We present a program for the calculation of continuum cross sections, spectra, angular distributions and analyzing powers according to various quantum-mechanical theories for statistical multi-step direct nuclear reactions.

  17. Reaction Coordinate, Free Energy, and Rate of Intramolecular Proton Transfer in Human Carbonic Anhydrase II.

    Science.gov (United States)

    Paul, Sanjib; Paul, Tanmoy Kumar; Taraphder, Srabani

    2018-03-22

    The role of structure and dynamics of an enzyme has been investigated at three different stages of its function including the chemical event it catalyzes. A one-pot computational method has been designed for each of these stages on the basis of classical and/or quantum mechanical-molecular mechanical molecular dynamics and transition path sampling simulations. For a pair of initial and final states A and B separated by a high free-energy barrier, using a two-stage selection process, several collective variables (CVs) are identified that can delineate A and B. However, these CVs are found to exhibit strong cross-coupling over the transition paths. A set of mutually orthogonal order parameters is then derived from these CVs and an optimal reaction coordinate, r, determined applying half-trajectory likelihood maximization along with a Bayesian information criterion. The transition paths are also used to project the multidimensional free energy surface and barrier crossing dynamics along r. The proposed scheme has been applied to the rate-determining intramolecular proton transfer reaction of the well-known enzyme human carbonic anhydrase II. The potential of mean force, F( r), in the absence of the chemical step is found to reproduce earlier results on the equilibrium population of two side-chain orientations of key residue His-64. Estimation of rate constants, k, from mean first passage times for the three different stages of catalysis shows that the rate-determining step of intramolecular proton transfer occurs with k ≃ 1.0 × 10 6 s -1 , in close agreement with known experimental results.

  18. Anaerobic digestion of citrus waste using two-stage membrane bioreactor

    Science.gov (United States)

    Millati, Ria; Lukitawesa; Dwi Permanasari, Ervina; Wulan Sari, Kartika; Nur Cahyanto, Muhammad; Niklasson, Claes; Taherzadeh, Mohammad J.

    2018-03-01

    Anaerobic digestion is a promising method to treat citrus waste. However, the presence of limonene in citrus waste inhibits anaerobic digestion process. Limonene is an antimicrobial compound and could inhibit methane forming bacteria that takes a longer time to recover than the injured acid forming bacteria. Hence, volatile fatty acids will be accumulated and methane production will be decreased. One way to solve this problem is by conducting anaerobic digestion process into two stages. The first step is aimed for hydrolysis, acidogenesis, and acetogenesis reactions and the second stage is aimed for methanogenesis reaction. The separation of the system would further allow each stage in their optimum conditions making the process more stable. In this research, anaerobic digestion was carried out in batch operations using 120 ml-glass bottle bioreactors in 2 stages. The first stage was performed in free-cells bioreactor, whereas the second stage was performed in both bioreactor of free cells and membrane bioreactor. In the first stage, the reactor was set into ‘anaerobic’ and ‘semi-aerobic’ conditions to examine the effect of oxygen on facultative anaerobic bacteria in acid production. In the second stage, the protection of membrane towards the cells against limonene was tested. For the first stage, the basal medium was prepared with 1.5 g VS of inoculum and 4.5 g VS of citrus waste. The digestion process was carried out at 55°C for four days. For the second stage, the membrane bioreactor was prepared with 3 g of cells that were encased and sealed in a 3×6 cm2 polyvinylidene fluoride membrane. The medium contained 40 ml basal medium and 10 ml liquid from the first stage. The bioreactors were incubated at 55°C for 2 days under anaerobic condition. The results from the first stage showed that the maximum total sugar under ‘anaerobic’ and ‘semi-aerobic’ conditions was 294.3 g/l and 244.7 g/l, respectively. The corresponding values for total volatile

  19. Turbine stage model

    International Nuclear Information System (INIS)

    Kazantsev, A.A.

    2009-01-01

    A model of turbine stage for calculations of NPP turbine department dynamics in real time was developed. The simulation results were compared with manufacturer calculations for NPP low-speed and fast turbines. The comparison results have shown that the model is valid for real time simulation of all modes of turbines operation. The model allows calculating turbine stage parameters with 1% accuracy. It was shown that the developed turbine stage model meets the accuracy requirements if the data of turbine blades setting angles for all turbine stages are available [ru

  20. Nonlinear Kinetics and Mechanism of Nile Blue Reaction with Acidic ...

    African Journals Online (AJOL)

    After an induction period, a swift reaction occurs. The overall reaction is NB+ + BrO3- react to P + CH3COOH + H+ + Br-, where P is the de-ethylated N-oxide derivative of nile blue. The rapid kinetics of the reaction of bromine direct with nile blue were also reported. A 11-step mechanism, consistent with the overall reaction ...

  1. Straightforward and highly efficient catalyst-free one-step synthesis of 2-(purin-6-yl)acetoacetic acid ethyl esters, (purin-6-yl)acetates, and 6-methylpurines through S(N)Ar-based reactions of 6-halopurines with ethyl acetoacetate.

    Science.gov (United States)

    Qu, Gui-Rong; Mao, Zhi-Jie; Niu, Hong-Ying; Wang, Dong-Chao; Xia, Chao; Guo, Hai-Ming

    2009-04-16

    A novel approach to the synthesis of purines bearing functionalized carbon substituents or methyl in position 6 was developed. Under different reaction conditions, 6-halopurine derivatives could react with ethyl acetoacetate efficiently to yield 2-(purin-6-yl)acetoacetic acid ethyl esters, (purin-6-yl)acetates and 6-methylpurines respectively. No metal catalyst and ligand were required.

  2. Explore the reaction mechanism of the Maillard reaction: a density functional theory study.

    Science.gov (United States)

    Ren, Ge-Rui; Zhao, Li-Jiang; Sun, Qiang; Xie, Hu-Jun; Lei, Qun-Fang; Fang, Wen-Jun

    2015-05-01

    The mechanism of Maillard reaction has been investigated by means of density functional theory calculations in the gaseous phase and aqueous solution. The Maillard reaction is a cascade of consecutive and parallel reaction. In the present model system study, glucose and glycine were taken as the initial reactants. On the basis of previous experimental results, the mechanisms of Maillard reaction have been proposed, and the possibility for the formation of different compounds have been evaluated through calculating the relative energy changes for different steps of reaction under different pH conditions. Our calculations reveal that the TS3 in Amadori rearrangement reaction is the rate-determining step of Maillard reaction with the activation barriers of about 66.7 and 68.8 kcal mol(-1) in the gaseous phase and aqueous solution, respectively. The calculation results are in good agreement with previous studies and could provide insights into the reaction mechanism of Maillard reaction, since experimental evaluation of the role of intermediates in the Maillard reaction is quite complicated.

  3. Regulation of Early Steps of GPVI Signal Transduction by Phosphatases: A Systems Biology Approach.

    Directory of Open Access Journals (Sweden)

    Joanne L Dunster

    2015-11-01

    Full Text Available We present a data-driven mathematical model of a key initiating step in platelet activation, a central process in the prevention of bleeding following Injury. In vascular disease, this process is activated inappropriately and causes thrombosis, heart attacks and stroke. The collagen receptor GPVI is the primary trigger for platelet activation at sites of injury. Understanding the complex molecular mechanisms initiated by this receptor is important for development of more effective antithrombotic medicines. In this work we developed a series of nonlinear ordinary differential equation models that are direct representations of biological hypotheses surrounding the initial steps in GPVI-stimulated signal transduction. At each stage model simulations were compared to our own quantitative, high-temporal experimental data that guides further experimental design, data collection and model refinement. Much is known about the linear forward reactions within platelet signalling pathways but knowledge of the roles of putative reverse reactions are poorly understood. An initial model, that includes a simple constitutively active phosphatase, was unable to explain experimental data. Model revisions, incorporating a complex pathway of interactions (and specifically the phosphatase TULA-2, provided a good description of the experimental data both based on observations of phosphorylation in samples from one donor and in those of a wider population. Our model was used to investigate the levels of proteins involved in regulating the pathway and the effect of low GPVI levels that have been associated with disease. Results indicate a clear separation in healthy and GPVI deficient states in respect of the signalling cascade dynamics associated with Syk tyrosine phosphorylation and activation. Our approach reveals the central importance of this negative feedback pathway that results in the temporal regulation of a specific class of protein tyrosine phosphatases in

  4. Friction of atomically stepped surfaces

    NARCIS (Netherlands)

    Dikken, R.J.; Thijsse, B.J.; Nicola, L.

    2017-01-01

    The friction behavior of atomically stepped metal surfaces under contact loading is studied using molecular dynamics simulations. While real rough metal surfaces involve roughness at multiple length scales, the focus of this paper is on understanding friction of the smallest scale of roughness:

  5. Dissecting a complex neurosurgical illustration: step-by-step development.

    Science.gov (United States)

    Suk, Ian

    2011-12-01

    Modern computer graphics software has enabled the medical illustrator to render very complex anatomy by composing many different layers of drawings simultaneously. This and the author's capacity to take an "editorial" approach to compress several chronological events into a single, comprehensive two-dimensional illustration are analyzed in a step-by-step process. Through a series of images, the article provides a visual synopsis of the development of an illustration for an extensive clinical case: total sacrectomy performed through an all-posterior approach. Originally given as a slide presentation at the American Association of Neurological Surgeons Theodore Kurze Lecture in April 2011, the article provides some detailed notes on the techniques the author used to develop a comprehensive neurosurgical illustration. Copyright © 2011 Elsevier Inc. All rights reserved.

  6. Extracurricular Activities in the Steps of Aim-Based Education

    Directory of Open Access Journals (Sweden)

    Yunus Yildiz

    2017-11-01

    Full Text Available Teachers and students’ competence applying the required steps in learning process takes paramount place depending on the aim-based education. Hence, by this study, it is aimed to enhance the students’ motivation by applying the right learning steps. In addition, this study facilitates teachers’ ability to make a decision about which methods, approaches and stage orders to follow confidently while teaching a foreign language to any learner. Consequently, it is emphasized that quality learning process needs motivation which may be provided by extracurricular activities.

  7. Fundamental Reaction Pathway and Free Energy Profile for Butyrylcholinesterase-Catalyzed Hydrolysis of Heroin

    Science.gov (United States)

    Qiao, Yan; Han, Keli; Zhan, Chang-Guo

    2013-01-01

    The pharmacological function of heroin requires an activation process which transforms heroin into 6-monoacetylmorphine (6-MAM) which is the most active form. The primary enzyme responsible for this activation process in human plasma is butyrylcholinesterase (BChE). The detailed reaction pathway of the activation process via BChE-catalyzed hydrolysis has been explored computationally, for the first time, in the present study by performing molecular dynamics simulation and first-principles quantum mechanical/molecular mechanical free energy calculations. It has been demonstrated that the whole reaction process includes acylation and deacylation stages. The acylation consists of two reaction steps, i.e. the nucleophilic attack on the carbonyl carbon of 3-acetyl group of heroin by the hydroxyl oxygen of Ser198 side chain and the dissociation of 6-MAM. The deacylation also consists of two reaction steps, i.e. the nucleophilic attack on the carbonyl carbon of the acyl-enzyme intermediate by a water molecule and the dissociation of the acetic acid from Ser198. The calculated free energy profile reveals that the second transition state (TS2) should be rate-determining. The structural analysis reveals that the oxyanion hole of BChE plays an important role in the stabilization of the rate-determining transition state TS2. The free energy barrier (15.9±0.2 or 16.1±0.2 kcal/mol) calculated for the rate-determining step is in good agreement with the experimentally-derived activation free energy (~16.2 kcal/mol), suggesting that the mechanistic insights obtained from the present computational study are reliable. The obtained structural and mechanistic insights could be valuable for use in future rational design of a novel therapeutic treatment of heroin abuse. PMID:23992153

  8. Troubleshooting in gene splicing by overlap extension: a step-wise method.

    Science.gov (United States)

    Mergulhão, F J; Kelly, A G; Monteiro, G A; Taipa, M A; Cabral, J M

    1999-10-01

    A step-wise method for cloning intron-containing genes from genomic DNA is described. The two exons of the human proinsulin gene were separately amplified in two steps using, in the first step, completely homologous primers. This reduces unwanted interactions between mismatched primers and a complex DNA template such as genomic DNA. The fragments were amplified in a second step polymerase chain reaction (PCR) using mismatched primers that incorporated additional bases complementary to the other exon, and these products were spliced together in a third step PCR.

  9. Staging of cutaneous melanoma

    NARCIS (Netherlands)

    P. Mohr (P.); A.M.M. Eggermont (Alexander); A. Hauschild (Axel); A. Buzaid (A.)

    2009-01-01

    textabstractThe American Joint Committee on Cancer (AJCC) staging of cutaneous melanoma is a continuously evolving system. The identification of increasingly more accurate prognostic factors has led to major changes in melanoma staging over the years, and the current system described in this review

  10. Catalysis of Photochemical Reactions.

    Science.gov (United States)

    Albini, A.

    1986-01-01

    Offers a classification system of catalytic effects in photochemical reactions, contrasting characteristic properties of photochemical and thermal reactions. Discusses catalysis and sensitization, examples of catalyzed reactions of excepted states, complexing ground state substrates, and catalysis of primary photoproducts. (JM)

  11. Comparisons of single-stage and two-stage approaches to genomic selection.

    Science.gov (United States)

    Schulz-Streeck, Torben; Ogutu, Joseph O; Piepho, Hans-Peter

    2013-01-01

    Genomic selection (GS) is a method for predicting breeding values of plants or animals using many molecular markers that is commonly implemented in two stages. In plant breeding the first stage usually involves computation of adjusted means for genotypes which are then used to predict genomic breeding values in the second stage. We compared two classical stage-wise approaches, which either ignore or approximate correlations among the means by a diagonal matrix, and a new method, to a single-stage analysis for GS using ridge regression best linear unbiased prediction (RR-BLUP). The new stage-wise method rotates (orthogonalizes) the adjusted means from the first stage before submitting them to the second stage. This makes the errors approximately independently and identically normally distributed, which is a prerequisite for many procedures that are potentially useful for GS such as machine learning methods (e.g. boosting) and regularized regression methods (e.g. lasso). This is illustrated in this paper using componentwise boosting. The componentwise boosting method minimizes squared error loss using least squares and iteratively and automatically selects markers that are most predictive of genomic breeding values. Results are compared with those of RR-BLUP using fivefold cross-validation. The new stage-wise approach with rotated means was slightly more similar to the single-stage analysis than the classical two-stage approaches based on non-rotated means for two unbalanced datasets. This suggests that rotation is a worthwhile pre-processing step in GS for the two-stage approaches for unbalanced datasets. Moreover, the predictive accuracy of stage-wise RR-BLUP was higher (5.0-6.1%) than that of componentwise boosting.

  12. Reactions of butadiyne. 1: The reaction with hydrogen atoms

    Science.gov (United States)

    Schwanebeck, W.; Warnatz, J.

    1984-01-01

    The reaction of hydrogen (H) atoms with butadiene (C4H2) was studied at room temperature in a pressure range between w mbar and 10 mbar. The primary step was an addition of H to C4H2 which is in its high pressure range at p 1 mbar. Under these conditions the following addition of a second H atom lies in the transition region between low and high pressure range. Vibrationally excited C4H4 can be deactivated to form buten-(1)-yne-(3)(C4H4) or decomposes into two C2H2 molecules. The rate constant at room temperature for primary step is given. The second order rate constant for the consumption of buten-(1)-yne-(3) is an H atom excess at room temperature is given.

  13. On Thermonuclear Reaction Rates

    OpenAIRE

    Haubold, H. J.; Mathai, A. M.

    1996-01-01

    Nuclear reactions govern major aspects of the chemical evolution of galaxies and stars. Analytic study of the reaction rates and reaction probability integrals is attempted here. Exact expressions for the reaction rates and reaction probability integrals for nuclear reactions in the cases of nonresonant, modified nonresonant, screened nonresonant and resonant cases are given. These are expressed in terms of H-functions, G-functions and in computable series forms. Computational aspects are als...

  14. Scanning Tunneling Microscopy Evidence for the Dissociation of Carbon Monoxide on Ruthenium Steps

    DEFF Research Database (Denmark)

    Tison, Yann; Nielsen, Kenneth; Mowbray, Duncan J.

    2012-01-01

    In heterogeneous catalysis, identifying the active site for key reaction steps is an important contribution for the optimization of industrial synthesis. The structure sensitivity of CO dissociation on a metal catalyst, which is the rate-limiting step for the methanation and the Fischer–Tropsch...

  15. DEFORMATION DEPENDENT TUL MULTI-STEP DIRECT MODEL

    International Nuclear Information System (INIS)

    WIENKE, H.; CAPOTE, R.; HERMAN, M.; SIN, M.

    2007-01-01

    The Multi-Step Direct (MSD) module TRISTAN in the nuclear reaction code EMPIRE has been extended in order to account for nuclear deformation. The new formalism was tested in calculations of neutron emission spectra emitted from the 232 Th(n,xn) reaction. These calculations include vibration-rotational Coupled Channels (CC) for the inelastic scattering to low-lying collective levels, ''deformed'' MSD with quadrupole deformation for inelastic scattering to the continuum, Multi-Step Compound (MSC) and Hauser-Feshbach with advanced treatment of the fission channel. Prompt fission neutrons were also calculated. The comparison with experimental data shows clear improvement over the ''spherical'' MSD calculations and JEFF-3.1 and JENDL-3.3 evaluations

  16. Deformation dependent TUL multi-step direct model

    International Nuclear Information System (INIS)

    Wienke, H.; Capote, R.; Herman, M.; Sin, M.

    2008-01-01

    The Multi-Step Direct (MSD) module TRISTAN in the nuclear reaction code EMPIRE has been extended to account for nuclear deformation. The new formalism was tested in calculations of neutron emission spectra emitted from the 232 Th(n,xn) reaction. These calculations include vibration-rotational Coupled Channels (CC) for the inelastic scattering to low-lying collective levels, 'deformed' MSD with quadrupole deformation for inelastic scattering to the continuum, Multi-Step Compound (MSC) and Hauser-Feshbach with advanced treatment of the fission channel. Prompt fission neutrons were also calculated. The comparison with experimental data shows clear improvement over the 'spherical' MSD calculations and JEFF-3.1 and JENDL-3.3 evaluations. (authors)

  17. Accelerated Monte Carlo simulation on the chemical stage in water radiolysis using GPU

    Science.gov (United States)

    Tian, Zhen; Jiang, Steve B.; Jia, Xun

    2017-04-01

    The accurate simulation of water radiolysis is an important step to understand the mechanisms of radiobiology and quantitatively test some hypotheses regarding radiobiological effects. However, the simulation of water radiolysis is highly time consuming, taking hours or even days to be completed by a conventional CPU processor. This time limitation hinders cell-level simulations for a number of research studies. We recently initiated efforts to develop gMicroMC, a GPU-based fast microscopic MC simulation package for water radiolysis. The first step of this project focused on accelerating the simulation of the chemical stage, the most time consuming stage in the entire water radiolysis process. A GPU-friendly parallelization strategy was designed to address the highly correlated many-body simulation problem caused by the mutual competitive chemical reactions between the radiolytic molecules. Two cases were tested, using a 750 keV electron and a 5 MeV proton incident in pure water, respectively. The time-dependent yields of all the radiolytic species during the chemical stage were used to evaluate the accuracy of the simulation. The relative differences between our simulation and the Geant4-DNA simulation were on average 5.3% and 4.4% for the two cases. Our package, executed on an Nvidia Titan black GPU card, successfully completed the chemical stage simulation of the two cases within 599.2 s and 489.0 s. As compared with Geant4-DNA that was executed on an Intel i7-5500U CPU processor and needed 28.6 h and 26.8 h for the two cases using a single CPU core, our package achieved a speed-up factor of 171.1-197.2.

  18. Why and How To Teach Acid-Base Reactions without Equilibrium.

    Science.gov (United States)

    Carlton, Terry S.

    1997-01-01

    Recommends an approach to the treatment of acid-base equilibria that involves treating each reaction as either going to completion or not occurring at all. Compares the method with the traditional approach step by step. (DDR)

  19. Staging for vulvar cancer.

    Science.gov (United States)

    Hacker, Neville F; Barlow, Ellen L

    2015-08-01

    Vulvar cancer has been staged by the International Federation of Gynaecology and Obstetrics (FIGO) since 1969, and the original staging system was based on clinical findings only. This system provided a very good spread of prognostic groupings. Because vulvar cancer is virtually always treated surgically, the status of the lymph nodes is the most important prognostic factor and this can only be determined with certainty by histological examination of resected lymph nodes, FIGO introduced a surgical staging system in 1988. This was modified in 1994 to include a category of microinvasive vulvar cancer (stage IA), because such patients have virtually no risk of lymph node metastases. This system did not give a reasonably even spread of prognostic groupings. In addition, patients with stage III disease were shown to be a heterogeneous group prognostically, and the number of positive nodes and the morphology of those nodes were not taken into account. A new surgical staging system for vulvar cancer was introduced by FIGO in 2009. Initial retrospective analyses have suggested that this new staging system has overcome the major deficiencies in the 1994 system. Crown Copyright © 2015. Published by Elsevier Ltd. All rights reserved.

  20. Staging for vaginal cancer.

    Science.gov (United States)

    Rajaram, Shalini; Maheshwari, Amita; Srivastava, Astha

    2015-08-01

    Vaginal cancer is a rare cancer comprising about 3% of all gynecologic cancers. Primary vaginal cancer should be carefully assigned as spread from cervix, vulva, and other metastatic tumors to vagina can occur. Although vaginal cancer traditionally occurs in older postmenopausal women, the incidence of high-risk human papillomavirus (HPV)-induced cancers is increasing in younger women. Squamous cell carcinoma is still the most common histopathologic type followed by adenocarcinoma. With decreasing use of diethylstilbestrol in pregnancy, non-diethylstilbestrol-associated cancers are described. The Federation Internationale de Gynecologie et d'Obstetrique (FIGO) staging of vaginal cancer (2009) follows the same rules as cervical cancer; it is clinically staged and allows the use of routine investigative modalities for staging. Although FIGO encourages the use of advanced imaging modalities, such as computed tomography, magnetic resonance imaging (MRI), and positron emission tomography (PET), to guide therapy, the imaging findings may not be used to change or reassign the stage. TNM staging is the pathologic staging system proposed by the American Joint Committee on Cancer, and information available from examination of the resected specimen, including pelvic and inguinal lymph nodes, may be used for staging. Copyright © 2015 Elsevier Ltd. All rights reserved.

  1. Exploring single electrode reactions in polymer electrolyte fuel cells

    Energy Technology Data Exchange (ETDEWEB)

    Kuhn, H.; Wokaun, A.; Scherer, G.G. [Paul Scherrer Institute, Electrochemistry Laboratory, 5232 Villigen (Switzerland)

    2007-01-20

    Utilising a pseudo-reference electrode in polymer electrolyte fuel cells allows for the separation of anodic and cathodic contributions to the entire cell impedance. Modelling the impedance responses by using equivalent circuits inhibits the investigation of kinetic parameters of the basic electrochemical reactions, which take place at single electrode-electrolyte interfaces. Therefore, we evaluate single electrode impedance measurements by a kinetic model, which is based on specific reaction pathways, either for the oxygen reduction reaction (ORR) or the hydrogen oxidation reaction (HOR). As a consequence, it is possible to obtain kinetic parameters for the specific reaction of interest. Furthermore, the information gained from the single electrode impedance measurements and the kinetic model can give insight into single reactions steps. In particular, the ORR has to include a chemical step in the reaction pathway. (author)

  2. Enhanced nitrogen removal in constructed wetlands: effects of dissolved oxygen and step-feeding.

    Science.gov (United States)

    Li, Fengmin; Lu, Lun; Zheng, Xiang; Ngo, Huu Hao; Liang, Shuang; Guo, Wenshan; Zhang, Xiuwen

    2014-10-01

    Four horizontal subsurface flow constructed wetlands (HSFCWs), named HSFCW1 (three-stage, without step-feeding), HSFCW2 (three-stage, with step-feeding), HSFCW3 (five-stage, without step-feeding) and HSFCW4 (five-stage, with step-feeding) were designed to investigate the effects of dissolved oxygen (DO) and step-feeding on nitrogen removal. High removal of 90.9% COD, 99.1% ammonium nitrogen and 88.1% total nitrogen (TN) were obtained simultaneously in HSFCW4 compared with HSFCW1-3. The excellent TN removal of HSFCW4 was due to artificial aeration provided sufficient DO for nitrification and the favorable anoxic environment created for denitrification. Step-feeding was a crucial factor because it provided sufficient carbon source (high COD: nitrate ratio of 14.3) for the denitrification process. Microbial activities and microbial abundance in HSFCW4 was found to be influenced by DO distribution and step-feeding, and thus improve TN removal. These results suggest that artificial aeration combined with step-feeding could achieve high nitrogen removal in HSFCWs. Copyright © 2014 Elsevier Ltd. All rights reserved.

  3. The reaction of the building structure with window unit to the explosiveimpact on the basis of dynamic equation solution

    Directory of Open Access Journals (Sweden)

    Doronin Fedor Leonidovich

    2014-01-01

    Full Text Available When designing residential buildings, additional measures for increasing the strength at dynamic effects indoors are not foreseen. The walls of the structure fixed in the framework are not designed for shock wave caused by explosion of utility gas. When designing a building, the task of the special dynamic load is often reduced to the calculation of the safe shock pressure, exceeding of which leads to the destruction of the structures. The wall with the window area under dynamic effects is a blast relief panel, which reduces the excess pressure inside the room. The proposed method of calculating a design with a window unit allows determining the dynamic reaction of the wall on explosive pulse. The proposed calculation technique of the constructions at shock loads allows tracing the changes of the inertial forces and displacements at any stage of dynamic response. The reaction to dynamic loads can be also set for non-monolithic structures, consisting of different materials with different conditions of fastening. Elastoplastic reaction of a brick wall with glass units was determined using step-by-step method of linear acceleration. The calculation of stress-strain state of brick walls with window panes determined the strength properties of the structures close to the monolithic version. The proposed technique of numerical solution of dynamic equations is applied only in the analysis of elastic systems, in which the dynamic characteristics remain unchanged throughout the reaction process.

  4. Staged bilateral carotid endarterectomy

    DEFF Research Database (Denmark)

    Schroeder, T; Sillesen, H; Engell, Hans Christian

    1986-01-01

    In a series of 56 staged bilateral carotid endarterectomies, new neurologic symptoms developed in 5% and 20% following the first and second procedure, respectively. All complications were transient or minor. The incidence of postendarterectomy hypertension was significantly higher following...... the second procedure, when operations were staged less than 3 weeks apart. A correlation between these hypertensive episodes and the occurrence of new neurologic symptoms could not be shown. However, as this correlation has been proved in several other reports, bilateral carotid endarterectomy is advised...... to be staged at least 3 weeks apart. In addition, a conservative attitude towards contralateral asymptomatic lesions is proposed....

  5. Staging of lung cancer.

    Science.gov (United States)

    de Groot, Patricia M; Carter, Brett W; Betancourt Cuellar, Sonia L; Erasmus, Jeremy J

    2015-06-01

    Primary lung cancer is the leading cause of cancer mortality in the world. Thorough clinical staging of patients with lung cancer is important, because therapeutic options and management are to a considerable degree dependent on stage at presentation. Radiologic imaging is an essential component of clinical staging, including chest radiography in some cases, computed tomography, MRI, and PET. Multiplanar imaging modalities allow assessment of features that are important for surgical, oncologic, and radiation therapy planning, including size of the primary tumor, location and relationship to normal anatomic structures in the thorax, and existence of nodal and/or metastatic disease. Copyright © 2015 Elsevier Inc. All rights reserved.

  6. Staging Mobilities / Designing Mobilities

    DEFF Research Database (Denmark)

    Jensen, Ole B.

    2015-01-01

    In recent years, urban research has taken a ‘mobilities turn’. There has been a developing realisation that mobilities do not ‘just happen.’ Mobilities are carefully and meticulously designed, planned and staged (from above). However, they are equally importantly acted out, performed and lived...... asks: what are the physical, social, technical, and cultural conditions to the staging of contemporary urban mobilities? The theoretical framing in the Staging mobilities book is applied to four in-depth cases in the accompanying volume Designing mobilities.This book explore how places, sites...

  7. Blogging business step-by-step startup guide

    CERN Document Server

    magazine, Entrepreneur

    2014-01-01

    This kit includes: Essential industry and business-specific startup steps with worksheets, calculators, checklists and more. Entrepreneur Editors' Start Your Own Business, a guide to starting any business and surviving the first three years. Downloadable, customizable business letters, sales letters, and other sample documents. Entrepreneur's Small Business Legal Toolkit. Blogs are still one of the internet's fastest-growing phenomena–and one of the best and easiest ways to make money online. Packed with the latest blog tools, tricks, and up-and-coming trends, this fully revised edition teache

  8. Determining Annealing Temperatures for Polymerase Chain Reaction

    Science.gov (United States)

    Porta, Angela R.; Enners, Edward

    2012-01-01

    The polymerase chain reaction (PCR) is a common technique used in high school and undergraduate science teaching. Students often do not fully comprehend the underlying principles of the technique and how optimization of the protocol affects the outcome and analysis. In this molecular biology laboratory, students learn the steps of PCR with an…

  9. Statistical theory of neutron-nuclear reactions

    International Nuclear Information System (INIS)

    Moldauer, P.A.

    1981-01-01

    In addition to the topics dealt with by the author in his lectures at the Joint IAEA/ICTP Course held at Trieste in 1978, recent developments in the statistical theory of multistep reactions are reviewed as well as the transport theory and intranuclear cascade approaches to the description of nuclear multi-step processes. (author)

  10. Synthesis of conformationally constrained peptidomimetics using multicomponent reactions

    NARCIS (Netherlands)

    Scheffelaar, R.; Klein Nijenhuis, R.A.; Paravidino, M.; Lutz, M.|info:eu-repo/dai/nl/304828971; Spek, A.L.|info:eu-repo/dai/nl/156517566; Ehlers, A.W.; de Kanter, F.J.J.; Groen, M.B.; Orru, R.V.A.; Ruijter, E.

    2009-01-01

    A novel modular synthetic approach toward constrained peptidomimetics is reported. The approach involves a highly efficient three-step sequence including two multicomponent reactions, thus allowing unprecedented diversification of both the peptide moieties and the turn-inducing scaffold. The

  11. Synthesis of Conformationally Constrained Peptidomimetics using Multicomponent Reactions

    NARCIS (Netherlands)

    Scheffelaar, R.; Nijenhuis, R.A.K.; Paravidino, M.; Lutz, M.; Spek, A.L; Ehlers, A.W.; de Kanter, F.J.J.; Groen, M.B.; Orru, R.V.A.; Ruijter, E.

    2009-01-01

    A novel modular synthetic approach toward constrained peptidomimetics is reported. The approach involves a highly efficient three-step sequence including two multicomponent reactions, thus allowing unprecedented diversification of both the peptide moieties and the turn-inducing scaffold. The

  12. Modeling the self-assembly of silica-templated nanoparticles in the initial stages of zeolite formation.

    Science.gov (United States)

    Chien, Szu-Chia; Auerbach, Scott M; Monson, Peter A

    2015-05-05

    The reaction ensemble Monte Carlo method was used to model the self-assembly and structure of silica nanoparticles found in the initial stages of the clear-solution synthesis of the silicalite-1 zeolite. Such nanoparticles, which comprise both silica and organic structure-directing agents (OSDAs), are believed to play a crucial role in the formation of silica nanoporous materials, yet very limited atomic-level structural information is available for these nanoparticles. We have modeled silica monomers as flexible tetrahedra with spring constants fitted in previous work to silica bulk moduli and OSDAs as spheres attracted to anionic silica monomers. We have studied one-step and two-step formation mechanisms, the latter involving the initial association of silica species and OSDAs driven by physical solution forces, followed by silica condensation/hydrolysis reactions simulated with reaction ensemble Monte Carlo. The two-step process with preassociation was found to be crucial for generating nearly spherical nanoparticles; otherwise, without preassociation they exhibited jagged, ramified structures. The two-step nanoparticles were found to exhibit a core-shell structure with mostly silica in the core surrounded by a diffuse shell of OSDAs, in agreement with SANS and SAXS data. The Qn distribution, quantifying silicon atoms bound to n bridging oxygens, found in the simulated nanoparticles is in broad agreement with (29)Si solid-state NMR data on smaller, 2 nm nanoparticle populations. Ring-size distributions from the simulated nanoparticles show that five-membered rings are prevalent when considering OSDA/silica mole fractions (∼0.2) that lead to silicalite-1, in agreement with a previous IR and modeling study. Nanoparticles simulated with higher OSDA concentrations show ring-size distributions shifted to smaller rings, with three-membered silica rings dominating at an OSDA/silica mole fraction of 0.8. Our simulations show no evidence of long-range silicalite-1

  13. Reaction rate of propene pyrolysis.

    Science.gov (United States)

    Han, Peipei; Su, Kehe; Liu, Yan; Wang, Yanli; Wang, Xin; Zeng, Qingfeng; Cheng, Laifei; Zhang, Litong

    2011-10-01

    The reaction rate of propene pyrolysis was investigated based on the elementary reactions proposed in Qu et al., J Comput Chem 2009, 31, 1421. The overall reaction rate was developed with the steady-state approximation and the rate constants of the elementary reactions were determined with the variational transition state theory. For the elementary reaction having transition state, the vibrational frequencies of the selected points along the minimum energy path were calculated with density functional theory at B3PW91/6-311G(d,p) level and the energies were improved with the accurate model chemistry method G3(MP2). For the elementary reaction without transition state, the frequencies were calculated with CASSCF/6-311G(d,p) and the energies were refined with the multireference configuration interaction method MRCISD/6-311G(d,p). The rate constants were evaluated within 200-2000 K and the fitted three-parameter expressions were obtained. The results are consistent with those in the literatures in most cases. For the overall rate, it was found that the logarithm of the rate and the reciprocal temperature have excellent linear relationship above 400 K, predicting that the rate follows a typical first-order law at high temperatures of 800-2000 K, which is also consistent with the experiments. The apparent activation energy in 800-2000 K is 317.3 kJ/mol from the potential energy surface of zero Kelvin. This value is comparable with the energy barriers, 365.4 and 403.7 kJ/mol, of the rate control steps. However, the apparent activation energy, 215.7 kJ/mol, developed with the Gibbs free energy surface at 1200 K is consistent with the most recent experimental result 201.9 ± 0.6 kJ/mol. Copyright © 2011 Wiley Periodicals, Inc.

  14. CLIC's three-step plan

    CERN Multimedia

    Katarina Anthony

    2012-01-01

    In early October, the Compact Linear Collider (CLIC) collaboration published its final Conceptual Design Report. Accompanying it was a strategic summary document that describes a whole new approach to the project: developing the linear e+e− collider in three energy stages. Though CLIC’s future still depends on signs from the LHC, its new staged approach to high-energy electron-positron physics for the post-LHC era is nothing short of convincing.   Instead of asking for a 48-kilometre-long commitment right off the bat, the CLIC collaboration is now presenting an accelerator that can be constructed in stages. For example, it could begin as an 11-kilometre 500 GeV accelerator that could later be extended to a 27-kilometre 1.5 TeV machine. Finally, after a decade or so of data taking, it could be taken up to the full 48-kilometre 3 TeV facility (see image 2). “Not only is the approach technically and financially practical, it also offers a very convincing physics prog...

  15. Acta Clinica Croatica: progress of a journal step by step.

    Science.gov (United States)

    Ramljak, Gordana

    2014-03-01

    The journal Acta Clinica Croatica (ACC) was founded in 1962 under the title Anali Bolnice Dr. M. Stojanović. In 1995, the title of the journal was changed into its present form and ever since all papers have been published in English. In 2000, the electronic (online) edition of the ACC was released in addition to the print version. The paper presents development of the journal from 1962 to 2012 based on the analysis of the following SCOPUS citation index parameters: type and number of documents published in the journal; number of citations; and number of domestic and foreign authors. The studied period was analyzed in three time segments: the period from 1995 to 1999, the period from 2000 to 2006 and the period from 2007 to 2012. The same parameters were analyzed in the Web of Science/SCI-Expanded bibliographic and citation index for the 2007-2012 period. The increasing number of documents, authors (both domestic and foreign) and citations demonstrates gradual rise in the quality, visibility and impact of the journal. The fifty years of experience show that a goal, at first very distant and almost unachievable, may be reached by progressing step by step.

  16. Stages of Colon Cancer

    Science.gov (United States)

    ... types of surgery : Local excision or simple polypectomy . Resection and anastomosis . This is done when the tumor is too ... stage I colon cancer usually includes the following: Resection and anastomosis . Use our clinical trial search to find NCI- ...

  17. Stages of Labor

    Science.gov (United States)

    ... Moms Need Blog News & Media News Videos Mission stories Ambassadors Spotlights Tools & Resources Frequently asked media questions ... can be born. This stage can last as short as 20 minutes or as long as several ...

  18. Multiple Stages 2

    DEFF Research Database (Denmark)

    Andreasen, John

    Multiple stages 2: theatrical futures, set design, community plays, cultural capitals, democracy & drama, WWII dramas, performance on adoption, promenade about emigration, qualities in political theatre, performance analysis, dramaturgical education, Toulmin Variations...

  19. Stages of Esophageal Cancer

    Science.gov (United States)

    ... the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds , ... stage of the cancer being treated. External and internal radiation therapy are used to treat esophageal cancer. A plastic ...

  20. Stages of Anal Cancer

    Science.gov (United States)

    ... the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds , ... stage of the cancer being treated. External and internal radiation therapy are used to treat anal cancer. Chemotherapy Chemotherapy ...

  1. Stages of Penile Cancer

    Science.gov (United States)

    ... the body to send radiation toward the cancer. Internal radiation therapy uses a radioactive substance sealed in needles, seeds , ... stage of the cancer being treated. External and internal radiation therapy are used to treat penile cancer. Chemotherapy Chemotherapy ...

  2. Staging interrail mobilities

    DEFF Research Database (Denmark)

    Jensen, Martin Trandberg; Gyimóthy, Szilvia; Jensen, Ole B.

    2016-01-01

    This article applies the multiscalar ‘staging mobilities’ framework from the emergent subfield of mobilities design to analyse an enduring European rail travel phenomenon, interrail. This discussion extends and contributes to tourism mobilities research. Second, the article enriches previous...

  3. Stages of ores formation

    International Nuclear Information System (INIS)

    Khasanov, A.Kh.

    1988-01-01

    Deposit formation (especially endogenous) is the complicated, multi-stage and long process. Establishment of deposit formation succession, age-specific correlations of minerals and aggregates have a high importance at solving genetic questions. Studying of minerals correlations and mineral aggregates, succession of their crystallization and other observations let restore the history of deposit formation, pick up in it different on duration and physical and chemical conditions stages

  4. Parallel and series-reaction mechanisms of wood and char combustion

    OpenAIRE

    Branca Carmen; di Blasi Colomba

    2004-01-01

    Thermo gravimetric curves in air of beech wood and char, obtained from conventional pyrolysis of beech wood at a laboratory scale, have been re-examined using different kinetic models. Multi-step reaction mechanisms consisting of either four (wood) or two (char) reactions are needed for accurate predictions of weight loss curves. In the case of wood, three reactions are linear in the reactant mass fraction whereas the fourth step presents a power-law dependence. A linear reaction for devolati...

  5. Reaction studies of hot silicon and germanium radicals. Progress report, September 1, 1979-August 31, 1980

    International Nuclear Information System (INIS)

    Gaspar, P.P.

    1980-01-01

    The experimental approach to attaining the goals of this research program is briefly outlined and the progress made in the last year is reviewed in sections entitled: (a) primary steps in the reaction of recoiling silicon and germanium atoms and the identification of reactive intermediates in the recoil reactions; (b) thermally induced silylene and germylene reactions; (c) ion-molecule reaction studies

  6. Block factorization of step response model predictive control problems

    DEFF Research Database (Denmark)

    Kufoalor, D. K.M.; Frison, Gianluca; Imsland, L.

    2017-01-01

    implemented in the HPMPC framework, and the performance is evaluated through simulation studies. The results confirm that a computationally fast controller is achieved, compared to the traditional step response MPC scheme that relies on an explicit prediction formulation. Moreover, the tailored condensing......By introducing a stage-wise prediction formulation that enables the use of highly efficient quadratic programming (QP) solution methods, this paper expands the computational toolbox for solving step response MPC problems. We propose a novel MPC scheme that is able to incorporate step response data...... algorithm exhibits superior performance and produces solution times comparable to that achieved when using a condensing scheme for an equivalent (but much smaller) state-space model derived from first-principles. Implementation aspects necessary for high performance on embedded platforms are discussed...

  7. Chemotherapy Toxicity On Quality of Life in Older Patients With Stage I, Stage II, Stage III, or Stage IV Ovarian Epithelial, Primary Peritoneal Cavity, or Fallopian Tube Cancer

    Science.gov (United States)

    2017-05-03

    Stage I Ovarian Cancer; Stage IA Fallopian Tube Cancer; Stage IB Fallopian Tube Cancer; Stage IC Fallopian Tube Cancer; Stage II Ovarian Cancer; Stage IIA Fallopian Tube Cancer; Stage IIB Fallopian Tube Cancer; Stage IIC Fallopian Tube Cancer; Stage III Ovarian Cancer; Stage III Primary Peritoneal Cancer; Stage IIIA Fallopian Tube Cancer; Stage IIIB Fallopian Tube Cancer; Stage IIIC Fallopian Tube Cancer; Stage IV Fallopian Tube Cancer; Stage IV Ovarian Cancer; Stage IV Primary Peritoneal Cancer

  8. Modelling of the spallation reaction: analysis and testing of nuclear models

    International Nuclear Information System (INIS)

    Toccoli, C.

    2000-01-01

    The spallation reaction is considered as a 2-step process. First a very quick stage (10 -22 , 10 -29 s) which corresponds to the individual interaction between the incident projectile and nucleons, this interaction is followed by a series of nucleon-nucleon collisions (intranuclear cascade) during which fast particles are emitted, the nucleus is left in a strongly excited level. Secondly a slower stage (10 -18 , 10 -19 s) during which the nucleus is expected to de-excite completely. This de-excitation is performed by evaporation of light particles (n, p, d, t, 3 He, 4 He) or/and fission or/and fragmentation. The HETC code has been designed to simulate spallation reactions, this simulation is based on the 2-steps process and on several models of intranuclear cascades (Bertini model, Cugnon model, Helder Duarte model), the evaporation model relies on the statistical theory of Weiskopf-Ewing. The purpose of this work is to evaluate the ability of the HETC code to predict experimental results. A methodology about the comparison of relevant experimental data with results of calculation is presented and a preliminary estimation of the systematic error of the HETC code is proposed. The main problem of cascade models originates in the difficulty of simulating inelastic nucleon-nucleon collisions, the emission of pions is over-estimated and corresponding differential spectra are badly reproduced. The inaccuracy of cascade models has a great impact to determine the excited level of the nucleus at the end of the first step and indirectly on the distribution of final residual nuclei. The test of the evaporation model has shown that the emission of high energy light particles is under-estimated. (A.C.)

  9. Spallation reactions - physics and applications

    International Nuclear Information System (INIS)

    Kelic, A.; Ricciardi, M.; Schmidt, K-H.

    2009-01-01

    -nucleon collisions with an intra-nuclear-cascade code. Most of the a lient features observed in the residual nuclide distributions are determined by the later de-excitation stage of the reaction due to the different possible de-excitation paths like evaporation of nucleons, light charged particles and intermediate mass fragments, fission and multi-fragmentation

  10. Efficient Green's Function Reaction Dynamics (GFRD) simulations for diffusion-limited, reversible reactions

    Science.gov (United States)

    Bashardanesh, Zahedeh; Lötstedt, Per

    2018-03-01

    In diffusion controlled reversible bimolecular reactions in three dimensions, a dissociation step is typically followed by multiple, rapid re-association steps slowing down the simulations of such systems. In order to improve the efficiency, we first derive an exact Green's function describing the rate at which an isolated pair of particles undergoing reversible bimolecular reactions and unimolecular decay separates beyond an arbitrarily chosen distance. Then the Green's function is used in an algorithm for particle-based stochastic reaction-diffusion simulations for prediction of the dynamics of biochemical networks. The accuracy and efficiency of the algorithm are evaluated using a reversible reaction and a push-pull chemical network. The computational work is independent of the rates of the re-associations.

  11. Steps in Researching the Music in Therapy

    DEFF Research Database (Denmark)

    Bonde, Lars Ole

    2007-01-01

    The chapter introduces a generic flowchart + step-by-step guide for microanalysis of music (compositions and improvisations) in music therapy.......The chapter introduces a generic flowchart + step-by-step guide for microanalysis of music (compositions and improvisations) in music therapy....

  12. Hydraulic Design of Stepped Spillways Workshop

    Science.gov (United States)

    Stepped chutes and spillways are commonly used for routing discharges during flood events. In addition, stepped chutes are used for overtopping protection of earthen embankments. Stepped spillways provide significant energy dissipation due to its stepped feature; as a result, the stilling basin as...

  13. Three-Step priming in lexical decision

    NARCIS (Netherlands)

    Chwilla, D.J.; Kolk, H.H.J.

    2002-01-01

    In two experiments, we investigated mediated two-step priming (e.g., from lion to stripes via tiger) and three-step priming (e.g., from mane to stripes via lion and tiger). Experiment 1 showed robust two-step priming in the double lexical decision task. In Experiment 2, we tested for three-step

  14. Maillard reaction and caramelization during hazelnut roasting: A multiresponse kinetic study.

    Science.gov (United States)

    Göncüoğlu Taş, Neslihan; Gökmen, Vural

    2017-04-15

    A comprehensive kinetic model indicating the elementary steps of Maillard reaction and caramelization during hazelnut roasting was proposed based on a multi-response kinetic modeling approach. Changes in the concentrations of sucrose, fructose, glucose, amino acids, 3-deoxyglucosone, 1-deoxyglucosone, 3,4-dideoxyglucosone, glyoxal, methylglyoxal, dimethylglyoxal, and 5-hydroxymethylfurfural were examined in hazelnuts during roasting at 150, 160 and 170°C for 15, 30, 60, 90, and 120min. The results suggested that 1,2-enolization was important in the interconversion of glucose and fructose, 5-hydroxymethylfurfural formation mainly proceeded via fructofuranosyl cation dehydration rather than 3-deoxglucosone, glucose contributed more than fructose and fructofuranosyl cation to the early stage of the Maillard reaction. Methylglyoxal and dimethylglyoxal were mainly formed from 1-deoxyglucosone with high reaction rate constants while glyoxal formed through glucose degradation. α-Dicarbonyl compounds could have a role in the formation of melanoidins. The temperature dependence of the reactions was complicated and could not be explained by the Arrhenius equation. Copyright © 2016 Elsevier Ltd. All rights reserved.

  15. Experimental Studies of quasi-fission reactions

    International Nuclear Information System (INIS)

    Back, B.B.

    1989-01-01

    A large number of recent experimental studies have shown that a substantial fraction of the total reaction cross section in heavy-ion reactions is found in fission-like processes, which do not result from the fission decay of a completely fused system. Following the suggestion of Swiatecki such processes, which represents a complete relaxation of the relative kinetic energy and a substantial amount of net mass transfer between the two fragments, are denoted quasi-fission reactions. They are distinct from compound fission reactions by bypassing the stage of a completely fused system. This typically means that they are associated with short reaction times, which results in several measurable characteristics such as broken forward-backward symmetries, large anisotropies of the angular distributions and increased widths of the fragment mass distributions. The distinction between quasi-fission and deep inelastic reactions is less stringent and has the character of a gradual evolution from one reaction type to the other, as found also as quasi-elastic reaction evolves into deeply inelastic processes as a function of the total kinetic energy loss. In the present paper some of the experimental data characterizing quasi-fission reactions are reviewed and discussed. (author)

  16. Reaction mechanisms and kinetics of processing glucose, xylose and glucose-xylose mixtures under hot compressed water conditions for predicting bio-crude composition

    DEFF Research Database (Denmark)

    Grigoras, Ionela; Toor, Saqib Sohail; Rosendahl, Lasse Aistrup

    Mechanisms for bio-crude formation during the conversion of glucose, xylose and glucose-xylose mixtures as biomass model compounds under hot compressed water conditions are investigated. Studies in literature have shown that the diverse products formed at the early stages of glucose or xylose...... conversion are 5-HMF, erythrose, glyceraldehyde, dihydroxyacetone, pyruvaldehyde, and saccharinic acids resulted through reactions such as dehydration, retro-aldol condensation and isomerization. However, these compounds are mostly water soluble compounds and lack the final steps towards formation of water...... insoluble components at longer reaction times. The effects of pressure, pH, catalyst and reaction time on the main products are examined thoroughly. The possible routes for the formation of oil compounds are developed....

  17. A small step in VLC systems - a big step in Li-Fi implementation

    Science.gov (United States)

    Rîurean, S. M.; Nagy, A. A.; Leba, M.; Ionica, A. C.

    2018-01-01

    Light is part of our sustainable environmental life so, using it would be the handiest and cheapest way for wireless communication. Since ever, light has been used to send messages in different ways and now, due to the high technological improvements, bits through light, at high speed on multiple paths, allow humans to communicate. Using the lighting system both for illumination and communication represents lately one of the worldwide main research issues with several implementations with real benefits. This paper presents a viable VLC system, that proves its sustainability for sending by light information not only few millimetres but meters away. This system has multiple potential applications in different areas where other communication systems are bottlenecked, too expensive, unavailable or even forbidden. Since a Li-Fi fully developed system requires bidirectional, multiple access communication, there are still some challenges towards a functional Li-Fi wireless network. Although important steps have been made, Li-Fi is still under experimental stage.

  18. Kinetics and mechanism of the ligand substitution reaction of di- ...

    Indian Academy of Sciences (India)

    The kinetics of the interaction between diethyldithiocarbamate (Et2DTC) and the title complex has been studied spectrophotometrically in aqueous medium as a function of nucleophile concentration, temperature and pH at constant ionic strength. The reaction is a two-step process in which the first step is liganddependent, ...

  19. Staging of extrahepatic cholangiocarcinoma

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Yong Eun; Choi, Jin-Young [Yonsei University College of Medicine, Department of Diagnostic Radiology, Research Institute of Radiological Science, Seoul (Korea); Kim, Myeong-Jin [Yonsei University College of Medicine, Department of Diagnostic Radiology, Research Institute of Radiological Science, Seoul (Korea); Yonsei University College of Medicine, Institute of Gastroenterology, Yonsei (Korea); Yonsei University Health System, Department of Diagnostic Radiology, Seoul (Korea); Park, Young Nyun [Yonsei University College of Medicine, Institute of Gastroenterology, Yonsei (Korea); Yonsei University College of Medicine, Department of Pathology, Yonsei (Korea); Lee, Yoon-Hee [Yonsei University College of Medicine, Department of Pathology, Yonsei (Korea)

    2008-10-15

    Preoperative staging of extrahepatic cholangiocarcinoma is important in determining the best treatment plan. Several classification systems have been suggested to determine the operability and extent of surgery. Longitudinal tumor extent is especially important in extrahepatic cholangiocarcinoma because operative methods differ depending on the tumor extent. The Bismuth-Corlette classification system provides useful information when planning for surgery. However, this classification system is not adequate for selecting surgical candidates. Anatomic variation of the bile duct and gross morphology of the tumor must be considered simultaneously. Lateral spread of the tumor can be evaluated based on the TNM staging provided by American Joint Committee on Cancer (AJCC). However, there is a potential for ambiguity in the distinction of T1 and T2 cancer from one another. In addition, T stage does not necessarily mean invasiveness. Blumgart T staging is helpful for the assessment of resectability with the consideration of nodal status and distant metastasis as suggested by the AJCC cancer staging system. Computed tomography (CT) and magnetic resonance imaging (MRI) are the primary tools used in the assessment of longitudinal and lateral spread of a tumor when determining respectability. Diagnostic laparoscopy and positron emission tomography (PET) may play additional roles in this regard. (orig.)

  20. Computational analysis of the mechanism of chemical reactions in terms of reaction phases: hidden intermediates and hidden transition States.

    Science.gov (United States)

    Kraka, Elfi; Cremer, Dieter

    2010-05-18

    Computational approaches to understanding chemical reaction mechanisms generally begin by establishing the relative energies of the starting materials, transition state, and products, that is, the stationary points on the potential energy surface of the reaction complex. Examining the intervening species via the intrinsic reaction coordinate (IRC) offers further insight into the fate of the reactants by delineating, step-by-step, the energetics involved along the reaction path between the stationary states. For a detailed analysis of the mechanism and dynamics of a chemical reaction, the reaction path Hamiltonian (RPH) and the united reaction valley approach (URVA) are an efficient combination. The chemical conversion of the reaction complex is reflected by the changes in the reaction path direction t(s) and reaction path curvature k(s), both expressed as a function of the path length s. This information can be used to partition the reaction path, and by this the reaction mechanism, of a chemical reaction into reaction phases describing chemically relevant changes of the reaction complex: (i) a contact phase characterized by van der Waals interactions, (ii) a preparation phase, in which the reactants prepare for the chemical processes, (iii) one or more transition state phases, in which the chemical processes of bond cleavage and bond formation take place, (iv) a product adjustment phase, and (v) a separation phase. In this Account, we examine mechanistic analysis with URVA in detail, focusing on recent theoretical insights (with a variety of reaction types) from our laboratories. Through the utilization of the concept of localized adiabatic vibrational modes that are associated with the internal coordinates, q(n)(s), of the reaction complex, the chemical character of each reaction phase can be identified via the adiabatic curvature coupling coefficients, A(n,s)(s). These quantities reveal whether a local adiabatic vibrational mode supports (A(n,s) > 0) or resists

  1. Propargylamine-isothiocyanate reaction: efficient conjugation chemistry in aqueous media

    DEFF Research Database (Denmark)

    Viart, Helene Marie-France; Larsen, T. S.; Tassone, Chiara

    2014-01-01

    A coupling reaction between secondary propargyl amines and isothiocyanates in aqueous media is described. The reaction is high-yielding and affords cyclized products within 2-24 h. A functionalized ether lipid was synthesized in 8 steps, formulated as liposomes with POPC and conjugated to FITC un...

  2. cyclo-addition reaction of triplet carbonyl compounds to substituted ...

    Indian Academy of Sciences (India)

    Abstract. Regioselectivity of the photochemical [2 + 2] cyclo-addition of triplet carbonyl compounds with a series of ground state electron-rich and electron-poor alkenes, the Paterno-Büchi reaction, is studied. Activation barriers for the first step of the triplet reaction are computed in the case of the O-attack. Next, the observed ...

  3. Composers on stage

    DEFF Research Database (Denmark)

    Groth, Sanne Krogh

    A trend on the scene of contemporary music is composers going on stage, performing their pieces themselves. Within a discourse of popular music, this is more the rule than exception, but when it comes to the context of contemporary scored music, the historical and aesthetic context differs......, and something quite different is undergoing. This paper intends to discuss three examples of performances in which the composer’s appearance on stage was an important part of the piece, - both when it came to the role as a performer and as an individual person – as representer and presenter. The paper intends...... to rise the following questions: What happens to the status of the author, when he suddenly (re-)appears on stage? How is this appearance to be understood in both a contemporary and historical context: Is it the musical virtuous appearing again, are we witnessing musical works turning...

  4. Study of single nucleon transfer in α + 12C reaction

    International Nuclear Information System (INIS)

    Pandey, R.; Rana, T.K.; Dey, A.; Bhattacharya, C.; Kundu, S.; Banerjee, K.; Mukherjee, G.; Ghosh, T.K.; Meena, J.K.; Pai, H.; Gohil, M.; Bhattacharya, S.; Biswas, M.

    2011-01-01

    Nucleon transfer reactions are of great significance for understanding the nuclear structure both for direct reaction studies as well as for production of nuclear states. Transfer reactions are simplest to interpret when either the initial and final state of the target nucleus has spin zero and when the conditions are such that the transition from the initial and final states occurs to a good approximation in a single step. In this paper, the measurement of angular momentum distribution and calculation of the spectroscopic factor for one nucleon transfer reaction in α + 12 C reaction have been reported

  5. Seven Stages of Bootstrap

    OpenAIRE

    Beran, Rudolf

    1994-01-01

    This essay is organized around the theoretical and computationalproblem of constructing bootstrap confidence sets, with forays into relatedtopics. The seven section headings are: Introduction; The Bootstrap World;Bootstrap Confidence Sets; Computing Bootstrap Confidence Sets; Quality ofBootstrap Confidence Sets; Iterated and Two-step Boostrap; Further Resources.

  6. Hemostatic step-by-step procedure to control presacral bleeding during laparoscopic total mesorectal excision.

    Science.gov (United States)

    D'Ambra, Luigi; Berti, Stefano; Bonfante, Pierfrancesco; Bianchi, Claudio; Gianquinto, Daniela; Falco, Emilio

    2009-04-01

    A new procedure of hemostasis during laparoscopic total mesorectal excision is described. In our surgical department, from January 2004 to December 2007, 128 patients underwent laparoscopic total mesorectal excision. Among them, 47 patients underwent laparoscopic anterior resection after preoperative radiotherapy, 68 patients underwent laparoscopic anterior resection without preoperative radiotherapy, and 13 patients underwent laparoscopic abdominal perineal amputation. In seven laparoscopic rectal surgery cases, we encountered unstoppable presacral bleeding, not amenable by conventional hemostatic solutions. In these cases we applied a simple staging hemostatic procedure. We first performed local compression: tamponing with a small gauze or absorbable fabric hemostat. If bleeding did not stop, we localized an epiploic or omental scrap and excised it by using bipolar forceps and use it as a plug on the tip of a grasping forceps. This plug is then put on the bleeding source and monopolar coagulation is applied by electrified dissecting forceps through the interposed grasping forceps. If bleeding did not stop, we used a little scrap of bovine pericardium graft and tacked it to the bleeding site using endoscopic helicoidal protack. Our experience suggests that this hemostatic step-by-step procedure is a valid option to control persistent presacral hemorrhages.

  7. [Adverse reactions to insulin].

    Science.gov (United States)

    Liñana, J J; Montoro, F J; Hernández, M D; Basomba, A

    1997-07-01

    The prevalence of allergic reactions to insuline has decreased during the last few years. Probably this is due to the use of the newly-developed recombinant human insuline. At present, adverse reactions to insuline occur in 5-10% of patients on therapy with insuline. Adverse reactions may be local (more frequent) or systemic (rare). Insuline resistance consists in a different type of immunological reaction. Diagnosis of allergy to insuline is based on clinical history and cutaneous and serological tests. Treatment depends upon the severity of the reaction. When insuline is indispensable despite a previous allergic reaction, a desensitization protocol may be implemented.

  8. Fast and calibration free determination of first order reaction kinetics in API synthesis using in-situ ATR-FTIR.

    Science.gov (United States)

    Rehbein, Moritz C; Husmann, Sascha; Lechner, Christian; Kunick, Conrad; Scholl, Stephan

    2017-09-28

    In early stages of drug development only sparse amounts of the key substances are available, which is problematic for the determination of important process data like reaction kinetics. Therefore, it is important to perform experiments as economically as possible, especially in regards to limiting compounds. Here we demonstrate the use of a temperature step experiment enabling the determination of complete reaction kinetics in a single non-isothermal experiment. In contrast to the traditionally used HPLC, the method takes advantage of the high measuring rate and the low amount of labor involved in using in-situ ATR-FTIR to determine time-dependent concentration-equivalent data. Copyright © 2017 Elsevier B.V. All rights reserved.

  9. The structure of stepped surfaces

    International Nuclear Information System (INIS)

    Algra, A.J.

    1981-01-01

    The state-of-the-art of Low Energy Ion Scattering (LEIS) as far as multiple scattering effects are concerned, is discussed. The ion fractions of lithium, sodium and potassium scattered from a copper (100) surface have been measured as a function of several experimental parameters. The ratio of the intensities of the single and double scattering peaks observed in ion scattering spectroscopy has been determined and ion scattering spectroscopy applied in the multiple scattering mode is used to determine the structure of a stepped Cu(410) surface. The average relaxation of the (100) terraces of this surface appears to be very small. The adsorption of oxygen on this surface has been studied with LEIS and it is indicated that oxygen absorbs dissociatively. (C.F.)

  10. Moral transhumanism: the next step.

    Science.gov (United States)

    Tennison, Michael N

    2012-08-01

    Although transhumanism offers hope for the transcendence of human biological limitations, it generates many intrinsic and consequential ethical concerns. The latter include issues such as the exacerbation of social inequalities and the exponentially increasing technological capacity to cause harm. To mitigate these risks, many thinkers have initiated investigations into the possibility of moral enhancement that could limit the power disparities facilitated by biotechnological enhancement. The arguments often focus on whether moral enhancement is morally permissible, or even obligatory, and remain largely in the realm of the hypothetical. This paper proposes that psilocybin may represent a viable, practical option for moral enhancement and that its further research in the context of moral psychology could comprise the next step in the development of moral transhumanism.

  11. Staging Collaborative Innovation Processes

    DEFF Research Database (Denmark)

    Pedersen, Signe; Clausen, Christian

    Organisations are currently challenged by demands for increased collaborative innovation internally as well as with external and new entities - e.g. across the value chain. The authors seek to develop new approaches to managing collaborative innovative processes in the context of open innovation...... and public private innovation partnerships. Based on a case study of a collaborative design process in a large electronics company the paper points to the key importance of staging and navigation of collaborative innovation process. Staging and navigation is presented as a combined activity: 1) to translate...

  12. Are stage IV vestibular schwannomas preoperatively different from other stages?

    Science.gov (United States)

    Tringali, Stéphane; Dubreuil, Christian; Zaouche, Sandra; Ferber-Viart, Chantal

    2008-01-01

    The aim of this study was to focus on the clinical and paraclinical symptoms of patients suffering from Stage IV vestibular schwannomas (VSs). In this prospective study, we included 734 patients who have VS and candidates for operation. Patients were classified as having Stage I, II, III, or IV tumors according to Tos criteria as evaluated by magnetic resonance imaging. PREOPERATIVE CLINICAL EVALUATION: We recorded the occurrence of complaints (%) and duration (yr) of hearing loss, tinnitus, and balance disorder. Preoperative paraclinical evaluation included pure-tone (PTA) and speech audiometry, auditory brainstem response (ABR) patterns, and vestibular deficit at videonystamography (VNG). Continuous variables were compared between Stage IV and other stages using analysis of variance. Qualitative variables expressed as a percentage of presence were compared between Stage IV and other stages using percentage comparison. Quantitative Parameters. Patients with Stage IV VS were significantly younger as compared with patients with other stages. Stage IV hearing loss was greater compared with other stages at 250 and 500 Hz but smaller at 2,000 and 8,000 Hz. We found no difference in the loss of PTA between Stage IV and the other stages. Speech discriminancy score was smaller in Stage IV. The durations of hearing loss, tinnitus, and balance disorders were similar whatever the tumor stage. Auditory brainstem response patterns showed no difference in Wave III latency between Stage IV VS and other stages, whereas Wave V latency and V-I interval were higher in Stage IV. Both ABR threshold and VNG caloric deficit were higher in Stage IV VS compared with other stages. Qualitative Parameters. The percentage of patients with Stage IV was lower than that with Stages II and III. The percentage of men and women was similar in all stages. The occurrence of hearing loss was similar in all stages, whereas that of tinnitus was lower in Stage IV compared with Stages I and II. In

  13. Preimages for Step-Reduced SHA-2

    DEFF Research Database (Denmark)

    Aoki, Kazumaro; Guo, Jian; Matusiewicz, Krystian

    2009-01-01

    In this paper, we present preimage attacks on up to 43-step SHA-256 (around 67% of the total 64 steps) and 46-step SHA-512 (around 57.5% of the total 80 steps), which significantly increases the number of attacked steps compared to the best previously published preimage attack working for 24 steps....... The time complexities are 2^251.9, 2^509 for finding pseudo-preimages and 2^254.9, 2^511.5 compression function operations for full preimages. The memory requirements are modest, around 2^6 words for 43-step SHA-256 and 46-step SHA-512. The pseudo-preimage attack also applies to 43-step SHA-224 and SHA-384...

  14. Manganese-Mediated Coupling Reaction of Vinylarenes and Aliphatic Alcohols

    Science.gov (United States)

    Zhang, Wei; Wang, Nai-Xing; Bai, Cui-Bing; Wang, Yan-Jing; Lan, Xing-Wang; Xing, Yalan; Li, Yi-He; Wen, Jia-Long

    2015-10-01

    Alcohols and alkenes are the most abundant and commonly used organic building blocks in the large-scale chemical synthesis. Herein, this is the first time to report a novel and operationally simple coupling reaction of vinylarenes and aliphatic alcohols catalyzed by manganese in the presence of TBHP (tert-butyl hydroperoxide). This coupling reaction provides the oxyalkylated products of vinylarenes with good regioselectivity and accomplishes with the principles of step-economies. A possible reaction mechanism has also been proposed.

  15. End-stage kidney disease

    Science.gov (United States)

    ... medlineplus.gov/ency/article/000500.htm End-stage kidney disease To use the sharing features on this page, please enable JavaScript. End-stage kidney disease (ESKD) is the last stage of long-term ( ...

  16. Stage theta pinch experiments

    International Nuclear Information System (INIS)

    Linford, R.K.; Downing, J.N.; Gribble, R.F.; Jacobson, A.R.; Platts, D.A.; Thomas, K.S.

    1975-01-01

    The Staged Theta Pinch program is designed to study the technological and physics problems associated with producing fat plasmas and separating the implosion heating from the adiabatic compression. Several methods of implosion heating are discussed. Circuit diagrams and theoretical magnetic field behavior are described for the STP and resonant heating experiments. (MOW)

  17. "Stage 40" Handbook.

    Science.gov (United States)

    Mill River Union High School, North Clarendon, VT.

    The policies, purposes, and guidelines of "Stage 40," an educational repertory company for students, are presented in this paper, which also explains how the company functions. The paper discusses the company's history, the relationship between the company and academics, and the responsibilities of a company member. Letters by the board…

  18. World Stage Design

    Index Scriptorium Estoniae

    2005-01-01

    12-19. III Torontos rahvusvaheline lavakujunduse, kostüümi ning valgus- ja helikujunduse näitus, mis toimub samaaegselt OISTATi (International Organization of Scenographers, Theatre Architects and Technicians) maailmakongressiga ja USITT (United States Institute for Theatre Technology) üritustega (konverents, Stage Expo). Eestit esindab lavakujunduse kategoorias Lilja Blumenfeld-Luhse

  19. stage/page/play

    DEFF Research Database (Denmark)

    context. Contributors: Per Brask, Dario Fo, Jette Barnholdt Hansen, Pil Hansen, Sven Åke Heed, Ulla Kallenbach, Sofie Kluge, Annelis Kuhlmann, Kela Kvam, Anna Lawaetz, Bent Flemming Nielsen, Franco Perrelli, Magnus Tessing Schneider, Antonio Scuderi. stage/page/play is published as a festschrift...

  20. Critical flux determination by flux-stepping

    DEFF Research Database (Denmark)

    Beier, Søren; Jonsson, Gunnar Eigil

    2010-01-01

    In membrane filtration related scientific literature, often step-by-step determined critical fluxes are reported. Using a dynamic microfiltration device, it is shown that critical fluxes determined from two different flux-stepping methods are dependent upon operational parameters such as step......, such values are more or less useless in itself as critical flux predictors, and constant flux verification experiments have to be conducted to check if the determined critical fluxes call predict sustainable flux regimes. However, it is shown that using the step-by-step predicted critical fluxes as start...

  1. Preequilibrium Nuclear Reactions

    International Nuclear Information System (INIS)

    Strohmaier, B.

    1988-01-01

    After a survey on existing experimental data on precompound reactions and a description of preequilibrium reactions, theoretical models and quantum mechanical theories of preequilibrium emission are presented. The 25 papers of this meeting are analyzed separately

  2. Microfluidic chemical reaction circuits

    Science.gov (United States)

    Lee, Chung-cheng [Irvine, CA; Sui, Guodong [Los Angeles, CA; Elizarov, Arkadij [Valley Village, CA; Kolb, Hartmuth C [Playa del Rey, CA; Huang, Jiang [San Jose, CA; Heath, James R [South Pasadena, CA; Phelps, Michael E [Los Angeles, CA; Quake, Stephen R [Stanford, CA; Tseng, Hsian-rong [Los Angeles, CA; Wyatt, Paul [Tipperary, IE; Daridon, Antoine [Mont-Sur-Rolle, CH

    2012-06-26

    New microfluidic devices, useful for carrying out chemical reactions, are provided. The devices are adapted for on-chip solvent exchange, chemical processes requiring multiple chemical reactions, and rapid concentration of reagents.

  3. Oral Hypersensitivity Reactions

    Science.gov (United States)

    ... such as cinnamon, peppermint, eugenol and menthol. Even dental floss and denture cleansers may contain ingredients known to cause a hypersensitivity reaction. Q: How can dental treatment trigger a hypersensitivity reaction? A: Some dental ...

  4. Fluorination reaction uranium dioxide by fluorine

    International Nuclear Information System (INIS)

    Ogata, Shinji; Homma, Shunji; Koga, Jiro; Matsumoto, Shiro; Sasahira, Akira; Kawamura, Fumio

    2004-01-01

    Kinetics of the fluorination reaction of uranium dioxide is studied using un-reacted core model with shrinking particles. The model includes the film mass transfer of fluorine gas and its diffusion in the particle. The rate constants of the model are determined by fitting the experimental data for 370-450degC. The model successfully represents the fluorination in this temperature range. The rate control step is identified by examining the rate constants of the model for 300-1,800degC. For temperature range up to 900degC, the fluorination reaction is rate controlling. For over 900degC, both mechanisms of the mass transfer of fluorine and the fluorination reaction control the rate of the fluorination. With further increase of the temperature, however, the fluorination reaction becomes so fast that the mass transfer of fluorine eventually controls the rate of the fluorination. (author)

  5. Chemical transport reactions

    CERN Document Server

    Schäfer, Harald

    2013-01-01

    Chemical Transport Reactions focuses on the processes and reactions involved in the transport of solid or liquid substances to form vapor phase reaction products. The publication first offers information on experimental and theoretical principles and the transport of solid substances and its special applications. Discussions focus on calculation of the transport effect of heterogeneous equilibria for a gas motion between equilibrium spaces; transport effect and the thermodynamic quantities of the transport reaction; separation and purification of substances by means of material transport; and

  6. Step styles of pedestrians at different densities

    Science.gov (United States)

    Wang, Jiayue; Weng, Wenguo; Boltes, Maik; Zhang, Jun; Tordeux, Antoine; Ziemer, Verena

    2018-02-01

    Stepping locomotion is the basis of human movement. The investigation of stepping locomotion and its affecting factors is necessary for a more realistic knowledge of human movement, which is usually referred to as walking with equal step lengths for the right and left leg. To study pedestrians’ stepping locomotion, a set of single-file movement experiments involving 39 participants of the same age walking on a highly curved oval course is conducted. The microscopic characteristics of the pedestrians including 1D Voronoi density, speed, and step length are calculated based on a projected coordinate. The influence of the projection lines with different radii on the measurement of these quantities is investigated. The step lengths from the straight and curved parts are compared using the Kolmogorov–Smirnov test. During the experiments, six different step styles are observed and the proportions of different step styles change with the density. At low density, the main step style is the stable-large step style and the step lengths of one pedestrian are almost constant. At high density, some pedestrians adjust and decrease their step lengths. Some pedestrians take relatively smaller and larger steps alternately to adapt to limited space.

  7. Thermonuclear reaction rates. III

    International Nuclear Information System (INIS)

    Harris, M.J.; Fowler, W.A.; Caughlan, G.R.; Zimmerman, B.A.

    1983-01-01

    Stellar thermonuclear reaction rates are revised and updated, adding a number of new important reaction rates. Several reactions with large negative Q-values are included, and examples of them are discussed. The importance of the decay rates for Mg-26(p,n) exp 26 Al and Al-26(n,p) exp 26 Mg for stellar studies is emphasized. 19 references

  8. Cluster knockout reactions

    Indian Academy of Sciences (India)

    2014-04-07

    Apr 7, 2014 ... advancements in the area of (α, 2α) reactions and heavy cluster knockout reactions are discussed. Importance of the finite-range vertex and the final-state interactions are brought out. Keywords. Cluster knockout reactions; FR-DWIA calculations; t-matrix effective interaction. PACS Nos 14.20.Pt; 24.10.

  9. ORGANIC REACTION MECHANISM CONTROVERSY ...

    African Journals Online (AJOL)

    Preferred Customer

    However, there are so many chemical reactions notably in organic chemistry where reactions may not directly lead to products. ... There are concepts that support these ideas but can they be proven to the ... Reaction mechanism is one such issue in organic chemistry that has attracted a lot of controversial comments from ...

  10. Resonant thermonuclear reaction rate

    International Nuclear Information System (INIS)

    Haubold, H.J.; Mathai, A.M.

    1986-01-01

    Basic physical principles for the resonant and nonresonant thermonuclear reaction rates are applied to find their standard representations for nuclear astrophysics. Closed-form representations for the resonant reaction rate are derived in terms of Meijer's G-function. Analytic representations of the resonant and nonresonant nuclear reaction rates are compared and the appearance of Meijer's G-function is discussed in physical terms

  11. One-step reduced kinetics for lean hydrogen-air deflagration

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Galisteo, D.; Sanchez, A.L. [Area de Mecanica de Fluidos, Univ. Carlos III de Madrid, Leganes 28911 (Spain); Linan, A. [ETSI Aeronauticos, Pl. Cardenal Cisneros 3, Madrid 28040 (Spain); Williams, F.A. [Dept. of Mechanical and Aerospace Engineering, University of California San Diego, La Jolla, CA 92093-0411 (United States)

    2009-05-15

    A short mechanism consisting of seven elementary reactions, of which only three are reversible, is shown to provide good predictions of hydrogen-air lean-flame burning velocities. This mechanism is further simplified by noting that over a range of conditions of practical interest, near the lean flammability limit all reaction intermediaries have small concentrations in the important thin reaction zone that controls the hydrogen-air laminar burning velocity and therefore follow a steady state approximation, while the main species react according to the global irreversible reaction 2H{sub 2} + O{sub 2} {yields} 2H{sub 2}O. An explicit expression for the non-Arrhenius rate of this one-step overall reaction for hydrogen oxidation is derived from the seven-step detailed mechanism, for application near the flammability limit. The one-step results are used to calculate flammability limits and burning velocities of planar deflagrations. Furthermore, implications concerning radical profiles in the deflagration and reasons for the success of the approximations are clarified. It is also demonstrated that adding only two irreversible direct recombination steps to the seven-step mechanism accurately reproduces burning velocities of the full detailed mechanism for all equivalence ratios at normal atmospheric conditions and that an eight-step detailed mechanism, constructed from the seven-step mechanism by adding to it the fourth reversible shuffle reaction, improves predictions of O and OH profiles. The new reduced-chemistry descriptions can be useful for both analytical and computational studies of lean hydrogen-air flames, decreasing required computation times. (author)

  12. Stage efficiency in the analysis of thermochemical water decomposition processes

    Science.gov (United States)

    Conger, W. L.; Funk, J. E.; Carty, R. H.; Soliman, M. A.; Cox, K. E.

    1976-01-01

    The procedure for analyzing thermochemical water-splitting processes using the figure of merit is expanded to include individual stage efficiencies and loss coefficients. The use of these quantities to establish the thermodynamic insufficiencies of each stage is shown. A number of processes are used to illustrate these concepts and procedures and to demonstrate the facility with which process steps contributing most to the cycle efficiency are found. The procedure allows attention to be directed to those steps of the process where the greatest increase in total cycle efficiency can be obtained.

  13. Steps to Advanced CANDU 600

    International Nuclear Information System (INIS)

    Oh, Yongshick; Brooks, G. L.

    1988-01-01

    The CANDU nuclear power system was developed from merging of AECL heavy water reactor technology with Ontario Hydro electrical power station expertise. The original four units of Ontario Hydro's Pickering Generating Station are the first full-scale commercial application of the CANDU system. AECL and Ontario Hydro then moved to the next evolutionary step, a more advanced larger scale design for four units at the Bruce Generating Station. CANDU 600 followed as a single unit nuclear electric power station design derived from an amalgam of features of the multiple unit Pickering and Bruce designs. The design of the CANDU 600 nuclear steam supply system is based on the Pickering design with improvements derived from the Bruce design. For example, most CANDU 600 auxiliary systems are based on Bruce systems, whereas the fuel handling system is based on the Pickering system. Four CANDU 600 units are in operation, and five are under construction in Romania. For the additional four units at Pickering Generating Station 'B', Ontario Hydro selected a replica of the Pickering 'A' design with limited design changes to maintain a high level of standardization across all eight units. Ontario Hydro applied a similar policy for the additional four units at Bruce Generating Station 'B'. For the four unit Darlington station, Ontario Hydro selected a design based on Bruce with improvements derived from operating experience, the CANDU 600 design and development programs

  14. Climbing Mount Efficiency--small steps, not giant leaps towards higher cloning success in farm animals.

    Science.gov (United States)

    Oback, Björn

    2008-07-01

    Despite more than a decade of research efforts, farm animal cloning by somatic cell nuclear transfer (SCNT) is still frustratingly inefficient. Inefficiency manifests itself at different levels, which are currently not well integrated. At the molecular level, it leads to widespread genetic, epigenetic and transcriptional aberrations in cloned embryos. At the organismal level, these genome-wide abnormalities compromise development of cloned foetuses and offspring. Specific molecular defects need to be causally linked to specific cloned phenotypes, in order to design specific treatments to correct them. Cloning efficiency depends on the ability of the nuclear donor cell to be fully reprogrammed into an embryonic state and the ability of the enucleated recipient cell to carry out the reprogramming reactions. It has been postulated that reprogrammability of the somatic donor cell epigenome is influenced by its differentiation status. However, direct comparisons between cells of divergent differentiation status within several somatic lineages have found no conclusive evidence for this. Choosing somatic stem cells as donors has not improved cloning efficiency, indicating that donor cell type may be less critical for cloning success. Different recipient cells, on the other hand, vary in their reprogramming ability. In bovine, using zygotes instead of oocytes has increased cloning success. Other improvements in livestock cloning efficiency include better coordinating donor cell type with cell cycle stage and aggregating cloned embryos. In the future, it will be important to demonstrate if these small increases at every step are cumulative, adding up to an integrated cloning protocol with greatly improved efficiency.

  15. Pivalolactone, 2. Copolyester synthesis via interchange reactions with polypivalolactone

    NARCIS (Netherlands)

    Tijsma, Edze Jan; Tijsma, E.J.; van der Does, L.; Bantjes, A.; Bantjes, Adriaan; Vulic, Ivan; Werumeus Buning, Gerard Hidde

    1993-01-01

    The synthesis of copolyesters via interchange reactions of polypivalolactone (PPVL) with several compounds was studied. The synthetical procedures are two-stage melt processes: in the first stage ester bonds in the polymer chain are cleaved and new groups are incorporated in the polymer chain, while

  16. Staged abdominal re-operation for abdominal trauma.

    Science.gov (United States)

    Taviloglu, Korhan

    2003-07-01

    To review the current developments in staged abdominal re-operation for abdominal trauma. To overview the steps of damage control laparotomy. The ever increasing importance of the resuscitation phase with current intensive care unit (ICU) support techniques should be emphasized. General surgeons should be familiar to staged abdominal re-operation for abdominal trauma and collaborate with ICU teams, interventional radiologists and several other specialties to overcome this entity.

  17. Statistical optimization for biodiesel production from waste frying oil through two-step catalyzed process

    Energy Technology Data Exchange (ETDEWEB)

    Charoenchaitrakool, Manop [Department of Chemical Engineering, Faculty of Engineering, Kasetsart University, Bangkok (Thailand); Center for Advanced Studies in Nanotechnology and its Applications in Chemical, Food and Agricultural Industries, Kasetsart University, Bangkok (Thailand); Thienmethangkoon, Juthagate [Department of Chemical Engineering, Faculty of Engineering, Kasetsart University, Bangkok (Thailand)

    2011-01-15

    The aim of this work was to investigate the optimum conditions in biodiesel production from waste frying oil using two-step catalyzed process. In the first step, sulfuric acid was used as a catalyst for the esterification reaction of free fatty acid and methanol in order to reduce the free fatty acid content to be approximate 0.5%. In the second step, the product from the first step was further reacted with methanol using potassium hydroxide as a catalyst. The Box-Behnken design of experiment was carried out using the MINITAB RELEASE 14, and the results were analyzed using response surface methodology. The optimum conditions for biodiesel production were obtained when using methanol to oil molar ratio of 6.1:1, 0.68 wt.% of sulfuric acid, at 51 C with a reaction time of 60 min in the first step, followed by using molar ratio of methanol to product from the first step of 9.1:1, 1 wt.% KOH, at 55 C with a reaction time of 60 min in the second step. The percentage of methyl ester in the obtained product was 90.56 {+-} 0.28%. In addition, the fuel properties of the produced biodiesel were in the acceptable ranges according to Thai standard for community biodiesel. (author)

  18. Identification of two-step chemical mechanisms using small temperature oscillations and a single tagged species.

    Science.gov (United States)

    Closa, F; Gosse, C; Jullien, L; Lemarchand, A

    2015-05-07

    In order to identify two-step chemical mechanisms, we propose a method based on a small temperature modulation and on the analysis of the concentration oscillations of a single tagged species involved in the first step. The thermokinetic parameters of the first reaction step are first determined. Then, we build test functions that are constant only if the chemical system actually possesses some assumed two-step mechanism. Next, if the test functions plotted using experimental data are actually even, the mechanism is attributed and the obtained constant values provide the rate constants and enthalpy of reaction of the second step. The advantage of the protocol is to use the first step as a probe reaction to reveal the dynamics of the second step, which can hence be relieved of any tagging. The protocol is anticipated to apply to many mechanisms of biological relevance. As far as ligand binding is considered, our approach can address receptor conformational changes or dimerization as well as competition with or modulation by a second partner. The method can also be used to screen libraries of untagged compounds, relying on a tracer whose concentration can be spectroscopically monitored.

  19. Multistage reaction pathways in detonating high explosives

    International Nuclear Information System (INIS)

    Li, Ying; Kalia, Rajiv K.; Nakano, Aiichiro; Nomura, Ken-ichi; Vashishta, Priya

    2014-01-01

    Atomistic mechanisms underlying the reaction time and intermediate reaction products of detonating high explosives far from equilibrium have been elusive. This is because detonation is one of the hardest multiscale physics problems, in which diverse length and time scales play important roles. Here, large spatiotemporal-scale reactive molecular dynamics simulations validated by quantum molecular dynamics simulations reveal a two-stage reaction mechanism during the detonation of cyclotrimethylenetrinitramine crystal. Rapid production of N 2 and H 2 O within ∼10 ps is followed by delayed production of CO molecules beyond ns. We found that further decomposition towards the final products is inhibited by the formation of large metastable carbon- and oxygen-rich clusters with fractal geometry. In addition, we found distinct unimolecular and intermolecular reaction pathways, respectively, for the rapid N 2 and H 2 O productions

  20. Analytical Approach for Estimating Preliminary Mass of ARES I Crew Launch Vehicle Upper Stage Structural Components

    Science.gov (United States)

    Aggarwal, Pravin

    2007-01-01

    In January 2004, President Bush gave the National Aeronautics and Space Administration (NASA) a vision for Space Exploration by setting our sight on a bold new path to go back to the Moon, then to Mars and beyond. In response to this vision, NASA started the Constellation Program, which is a new exploration launch vehicle program. The primary mission for the Constellation Program is to carry out a series of human expeditions ranging from Low Earth Orbit to the surface of Mars and beyond for the purposes of conducting human exploration of space, as specified by the Vision for Space Exploration (VSE). The intent is that the information and technology developed by this program will provide the foundation for broader exploration activities as our operational experience grows. The ARES I Crew Launch Vehicle (CLV) has been designated as the launch vehicle that will be developed as a "first step" to facilitate the aforementioned human expeditions. The CLV Project is broken into four major elements: First Stage, Upper Stage Engine, Upper Stage (US), and the Crew Exploration Vehicle (CEV). NASA's Marshall Space Flight Center (MSFC) is responsible for the design of the CLV and has the prime responsibility to design the upper stage of the vehicle. The US is the second propulsive stage of the CLV and provides CEV insertion into low Earth orbit (LEO) after separation from the First Stage of the Crew Launch Vehicle. The fully integrated Upper Stage is a mix of modified existing heritage hardware (J-2X Engine) and new development (primary structure, subsystems, and avionics). The Upper Stage assembly is a structurally stabilized cylindrical structure, which is powered by a single J-2X engine which is developed as a separate Element of the CLV. The primary structure includes the load bearing liquid hydrogen (LH2) and liquid oxygen (LOX) propellant tanks, a Forward Skirt, the Intertank structure, the Aft Skirt and the Thrust Structure. A Systems Tunnel, which carries fluid and

  1. Step-Wise Migration : Evidence from Indonesia

    NARCIS (Netherlands)

    Pardede, Elda; McCann, Philip; Venhorst, Viktor

    2016-01-01

    The objective of this paper is to study multiple internal migration trajectories in Indonesia, with special attention to step-wise migration. Step-wise migration involves moves with smaller steps from village to nearby small town, to larger town, and then to big cities rather than a direct move from

  2. The Complexity of One-Step Equations

    Science.gov (United States)

    Ngu, Bing

    2014-01-01

    An analysis of one-step equations from a cognitive load theory perspective uncovers variation within one-step equations. The complexity of one-step equations arises from the element interactivity across the operational and relational lines. The higher the number of operational and relational lines, the greater the complexity of the equations.…

  3. Ten steps to successful software process improvement

    Science.gov (United States)

    Kandt, R. K.

    2003-01-01

    This paper identifies ten steps for managing change that address organizational and cultural issues. Four of these steps are critical, that if not done, will almost guarantee failure. This ten-step program emphasizes the alignment of business goals, change process goals, and the work performed by the employees of an organization.

  4. Ten Steps to Making Evaluation Matter

    Science.gov (United States)

    Sridharan, Sanjeev; Nakaima, April

    2011-01-01

    This paper proposes ten steps to make evaluations matter. The ten steps are a combination of the usual recommended practice such as developing program theory and implementing rigorous evaluation designs with a stronger focus on more unconventional steps including developing learning frameworks, exploring pathways of evaluation influence, and…

  5. Staging Collaborative Innovation Processes

    DEFF Research Database (Denmark)

    Pedersen, Signe; Clausen, Christian

    Organisations are currently challenged by demands for increased collaborative innovation internally as well as with external and new entities - e.g. across the value chain. The authors seek to develop new approaches to managing collaborative innovative processes in the context of open innovation...... and public private innovation partnerships. Based on a case study of a collaborative design process in a large electronics company the paper points to the key importance of staging and navigation of collaborative innovation process. Staging and navigation is presented as a combined activity: 1) to translate...... the diverse matters of concern into a coherent product or service concept, and 2) in the same process move these diverse holders of the matters of concern into a translated actor network which carry or support the concept....

  6. Staging Sociotechnical Spaces

    DEFF Research Database (Denmark)

    Clausen, Christian; Yoshinaka, Yutaka

    2007-01-01

    The management of innovation and product development is increasingly facing complex challenges of staging design processes across heterogeneous organisational spaces, with multiple actor-concerns and sources of knowledge. This paper addresses how insights from the Actor-Network Theory and political...... process theory may contribute to a reflexive understanding of design as the staging of socio-technical relations and processes cutting across boundaries of diverse organisational, political and knowledge domains. This idea is pursued through the notion of ‘socio-technical spaces’. Socio-technical space...... of product development. The concept of socio-technical spaces is further illustrated through actual examples from industry dealing with early conceptualisation in product development and the role played by management concepts in the configuration of spaces....

  7. Piwi proteins and piRNAs step onto the systems biology stage

    OpenAIRE

    Clark, Josef P.; Lau, Nelson C.

    2014-01-01

    Animal germ cells are totipotent because they maintain a highly unique and specialized epigenetic state for its genome. To accomplish this, germ cells express a rich repertoire of specialized RNA binding protein complexes such as the Piwi proteins and Piwi-interacting RNAs (piRNAs): a germ-cell enriched pathway of the RNA interference (RNAi) phenomenon which includes microRNA and endogenous small interfering RNA pathways. Piwi proteins and piRNAs are deeply conserved in animal evolution and p...

  8. Linking Early Life Stages: The First Step towards Lifecourse Risk Assessment

    Science.gov (United States)

    The abstract is the overview of a workshop proposed for inclusion in 2015 Society of Toxicology annual meeting program. The workshop will introduce the audience to lifecourse theory and speakers will provide examples of using PBPK models to link exposures and outcomes resulting ...

  9. Traffic safety and step-by-step driving licence for young people

    DEFF Research Database (Denmark)

    Tønning, Charlotte; Agerholm, Niels

    2017-01-01

    Young novice car drivers are much more accident-prone than other drivers - up to 10 times that of their parents' generation. A central solution to improve the traffic safety for this group is implementation of a step-by-step driving licence. A number of countries have introduced a step...... presents a review of safety effects from step-by-step driving licence schemes. Most of the investigated schemes consist of a step-by-step driving licence with Step 1) various tests and education, Step 2) a period where driving is only allowed together with an experienced driver and Step 3) driving without...... companion is allowed but with various restrictions and, in some cases, additional driving education and tests. In general, a step-by-step driving licence improves traffic safety even though the young people are permitted to drive a car earlier on. The effects from driving with an experienced driver vary...

  10. Calibration of Nanopositioning Stages

    Directory of Open Access Journals (Sweden)

    Ning Tan

    2015-12-01

    Full Text Available Accuracy is one of the most important criteria for the performance evaluation of micro- and nanorobots or systems. Nanopositioning stages are used to achieve the high positioning resolution and accuracy for a wide and growing scope of applications. However, their positioning accuracy and repeatability are not well known and difficult to guarantee, which induces many drawbacks for many applications. For example, in the mechanical characterisation of biological samples, it is difficult to perform several cycles in a repeatable way so as not to induce negative influences on the study. It also prevents one from controlling accurately a tool with respect to a sample without adding additional sensors for closed loop control. This paper aims at quantifying the positioning repeatability and accuracy based on the ISO 9283:1998 standard, and analyzing factors influencing positioning accuracy onto a case study of 1-DoF (Degree-of-Freedom nanopositioning stage. The influence of thermal drift is notably quantified. Performances improvement of the nanopositioning stage are then investigated through robot calibration (i.e., open-loop approach. Two models (static and adaptive models are proposed to compensate for both geometric errors and thermal drift. Validation experiments are conducted over a long period (several days showing that the accuracy of the stage is improved from typical micrometer range to 400 nm using the static model and even down to 100 nm using the adaptive model. In addition, we extend the 1-DoF calibration to multi-DoF with a case study of a 2-DoF nanopositioning robot. Results demonstrate that the model efficiently improved the 2D accuracy from 1400 nm to 200 nm.

  11. Two stage turbine for rockets

    Science.gov (United States)

    Veres, Joseph P.

    1993-01-01

    The aerodynamic design and rig test evaluation of a small counter-rotating turbine system is described. The advanced turbine airfoils were designed and tested by Pratt & Whitney. The technology represented by this turbine is being developed for a turbopump to be used in an advanced upper stage rocket engine. The advanced engine will use a hydrogen expander cycle and achieve high performance through efficient combustion of hydrogen/oxygen propellants, high combustion pressure, and high area ratio exhaust nozzle expansion. Engine performance goals require that the turbopump drive turbines achieve high efficiency at low gas flow rates. The low mass flow rates and high operating pressures result in very small airfoil heights and diameters. The high efficiency and small size requirements present a challenging turbine design problem. The shrouded axial turbine blades are 50 percent reaction with a maximum thickness to chord ratio near 1. At 6 deg from the tangential direction, the nozzle and blade exit flow angles are well below the traditional design minimum limits. The blade turning angle of 160 deg also exceeds the maximum limits used in traditional turbine designs.

  12. A single-step synthesis and the kinetic mechanism for monodisperse and hexagonal-phase NaYF4:Yb, Er upconversion nanophosphors.

    Science.gov (United States)

    Shan, Jingning; Ju, Yiguang

    2009-07-08

    A single-step synthesis for monodisperse and hexagonal-phase (beta) NaYF(4):Yb, Er upconversion nanophosphors (UCNPs) with a consistent hexagonal prism shape in the size range from 18 to 200 nm was achieved. The kinetic mechanisms for the particle phase transition and growth were examined. The beta-UCNPs were obtained via co-thermolysis of trifluoroacetate precursors in octadecene (ODE) with combined ligands of oleic acid (OA) and trioctylphosphine (TOP). The experimental results showed that the combined OA-TOP ligand was crucial for changing the surface energy and controlling the particle shape over a broad size range. It was found that the particle sizes could be controlled by varying the molar ratios of Na(CF(3)COO)/Re(CF(3)COO)(3) (Re = Y, Yb, and Er). A high Na/Re ratio accelerated the cubic-phase (alpha)-->beta transition and promoted the growth of smaller beta-UCNPs. The formation of beta-UCNPs was classified into kinetic and diffusion controlled stages, depending on the reaction temperature and the dominant crystalline phases formed in each stage. In stage I, 250-310 degrees C, NaF generation was the limiting step and alpha-UCNPs were formed via a 'burst of nucleation'. In stage II, above 310 degrees C, the alpha-UCNPs formed were re-dissolved and the growth of beta-UCNPs was a diffusion controlled process governed by the Gibbs-Thompson effect. A quasi-steady-state species assumption for NaF and a chemical potential equilibrium in the solution were introduced to explain the particle size dependence on Na/Re ratios. The study of UC luminescence showed that the UC intensity was proportional to the sizes of the beta-UCNPs.

  13. Stochastic surface walking reaction sampling for resolving heterogeneous catalytic reaction network: A revisit to the mechanism of water-gas shift reaction on Cu

    Science.gov (United States)

    Zhang, Xiao-Jie; Shang, Cheng; Liu, Zhi-Pan

    2017-10-01

    Heterogeneous catalytic reactions on surface and interfaces are renowned for ample intermediate adsorbates and complex reaction networks. The common practice to reveal the reaction mechanism is via theoretical computation, which locates all likely transition states based on the pre-guessed reaction mechanism. Here we develop a new theoretical method, namely, stochastic surface walking (SSW)-Cat method, to resolve the lowest energy reaction pathway of heterogeneous catalytic reactions, which combines our recently developed SSW global structure optimization and SSW reaction sampling. The SSW-Cat is automated and massively parallel, taking a rough reaction pattern as input to guide reaction search. We present the detailed algorithm, discuss the key features, and demonstrate the efficiency in a model catalytic reaction, water-gas shift reaction on Cu(111) (CO + H2O → CO2 + H2). The SSW-Cat simulation shows that water dissociation is the rate-determining step and formic acid (HCOOH) is the kinetically favorable product, instead of the observed final products, CO2 and H2. It implies that CO2 and H2 are secondary products from further decomposition of HCOOH at high temperatures. Being a general purpose tool for reaction prediction, the SSW-Cat may be utilized for rational catalyst design via large-scale computations.

  14. 48 CFR 52.214-25 - Step Two of Two-Step Sealed Bidding.

    Science.gov (United States)

    2010-10-01

    ... 48 Federal Acquisition Regulations System 2 2010-10-01 2010-10-01 false Step Two of Two-Step... Clauses 52.214-25 Step Two of Two-Step Sealed Bidding. As prescribed in 14.201-6(t), insert the following provision: Step Two of Two-Step Sealed Bidding (APR 1985) (a) This invitation for bids is issued to initiate...

  15. One-step production of biodiesel from Nannochloropsis sp. on solid base Mg-Zr catalyst

    International Nuclear Information System (INIS)

    Li, Yuesong; Lian, Shuang; Tong, Dongmei; Song, Ruili; Yang, Wenyan; Fan, Yong; Qing, Renwei; Hu, Changwei

    2011-01-01

    Nannochloropsis sp., one kind of green microalgae cultivated autotrophically and axenically in laboratory, is used as raw material to produce biodiesel by one-step method in an amended reactor. The effects of several reaction parameters on transesterification over Mg-Zr solid base catalyst were investigated through both conventional method and one-step method. One-step method could give a higher yield of methyl ester than conventional two-step method, which demonstrates that the present one-step method is suitable for biodiesel production from the microalgae Nannochloropsis sp. Moreover, the present one-step method realizes the convenient in situ separation of catalyst from microalgae residue which can be easily used consequently, reducing the procedure units as well as the overall costs.

  16. Alternating electron and proton transfer steps in photosynthetic water oxidation.

    Science.gov (United States)

    Klauss, André; Haumann, Michael; Dau, Holger

    2012-10-02

    Water oxidation by cyanobacteria, algae, and plants is pivotal in oxygenic photosynthesis, the process that powers life on Earth, and is the paradigm for engineering solar fuel-production systems. Each complete reaction cycle of photosynthetic water oxidation requires the removal of four electrons and four protons from the catalytic site, a manganese-calcium complex and its protein environment in photosystem II. In time-resolved photothermal beam deflection experiments, we monitored apparent volume changes of the photosystem II protein associated with charge creation by light-induced electron transfer (contraction) and charge-compensating proton relocation (expansion). Two previously invisible proton removal steps were detected, thereby filling two gaps in the basic reaction-cycle model of photosynthetic water oxidation. In the S(2) → S(3) transition of the classical S-state cycle, an intermediate is formed by deprotonation clearly before electron transfer to the oxidant (Y Z OX). The rate-determining elementary step (τ, approximately 30 µs at 20 °C) in the long-distance proton relocation toward the protein-water interface is characterized by a high activation energy (E(a) = 0.46 ± 0.05 eV) and strong H/D kinetic isotope effect (approximately 6). The characteristics of a proton transfer step during the S(0) → S(1) transition are similar (τ, approximately 100 µs; E(a) = 0.34 ± 0.08 eV; kinetic isotope effect, approximately 3); however, the proton removal from the Mn complex proceeds after electron transfer to . By discovery of the transient formation of two further intermediate states in the reaction cycle of photosynthetic water oxidation, a temporal sequence of strictly alternating removal of electrons and protons from the catalytic site is established.

  17. Solar array stepping to minimize array excitation

    Science.gov (United States)

    Bhat, Mahabaleshwar K. P. (Inventor); Liu, Tung Y. (Inventor); Plescia, Carl T. (Inventor)

    1989-01-01

    Mechanical oscillations of a mechanism containing a stepper motor, such as a solar-array powered spacecraft, are reduced and minimized by the execution of step movements in pairs of steps, the period between steps being equal to one-half of the period of torsional oscillation of the mechanism. Each pair of steps is repeated at needed intervals to maintain desired continuous movement of the portion of elements to be moved, such as the solar array of a spacecraft. In order to account for uncertainty as well as slow change in the period of torsional oscillation, a command unit may be provided for varying the interval between steps in a pair.

  18. Storybridging: Four steps for constructing effective health narratives

    Science.gov (United States)

    Boeijinga, Anniek; Hoeken, Hans; Sanders, José

    2017-01-01

    Objective: To develop a practical step-by-step approach to constructing narrative health interventions in response to the mixed results and wide diversity of narratives used in health-related narrative persuasion research. Method: Development work was guided by essential narrative characteristics as well as principles enshrined in the Health Action Process Approach. Results: The ‘storybridging’ method for constructing health narratives is described as consisting of four concrete steps: (a) identifying the stage of change, (b) identifying the key elements, (c) building the story, and (d) pre-testing the story. These steps are illustrated by means of a case study in which an effective narrative health intervention was developed for Dutch truck drivers: a high-risk, underprivileged occupational group. Conclusion: Although time and labour intensive, the Storybridging approach suggests integrating the target audience as an important stakeholder throughout the development process. Implications and recommendations are provided for health promotion targeting truck drivers specifically and for constructing narrative health interventions in general. PMID:29276232

  19. Strong Stability Preserving Two-step Runge–Kutta Methods

    KAUST Repository

    Ketcheson, David I.

    2011-12-22

    We investigate the strong stability preserving (SSP) property of two-step Runge–Kutta (TSRK) methods. We prove that all SSP TSRK methods belong to a particularly simple subclass of TSRK methods, in which stages from the previous step are not used. We derive simple order conditions for this subclass. Whereas explicit SSP Runge–Kutta methods have order at most four, we prove that explicit SSP TSRK methods have order at most eight. We present explicit TSRK methods of up to eighth order that were found by numerical search. These methods have larger SSP coefficients than any known methods of the same order of accuracy and may be implemented in a form with relatively modest storage requirements. The usefulness of the TSRK methods is demonstrated through numerical examples, including integration of very high order weighted essentially non-oscillatory discretizations.

  20. Temperature dependence of the step free energy

    International Nuclear Information System (INIS)

    Zandvliet, H. J. W.; Gurlu, O.; Poelsema, Bene

    2001-01-01

    We have derived an expression for the step free energy that includes the usual thermally induced step meandering term and a vibrational entropy term related to the step edge atoms. The latter term results from the reduced local coordination of the step atoms with respect to the terrace atoms and was introduced recently by Frenken and Stoltze as well as by Bonzel and Emundts. Additionally, we have added third and fourth terms that deal with the vibrational entropy contribution of the thermally generated step and kink atoms. At elevated temperatures the two latter vibrational entropy terms are of the same order of magnitude. Incorporation of these vibrational entropy terms results in a faster decrease of the step free energy with increasing temperature than anticipated previously. This enhanced temperature dependence of the step free energy results in a lower thermal roughening temperature of the facet

  1. First steps in random walks from tools to applications

    CERN Document Server

    Klafter, J

    2011-01-01

    The name ""random walk"" for a problem of a displacement of a point in a sequence of independent random steps was coined by Karl Pearson in 1905 in a question posed to readers of ""Nature"". The same year, a similar problem was formulated by Albert Einstein in one of his Annus Mirabilis works. Even earlier such a problem was posed by Louis Bachelier in his thesis devoted to the theory of financial speculations in 1900. Nowadays the theory of random walks has proved useful in physics andchemistry (diffusion, reactions, mixing in flows), economics, biology (from animal spread to motion of subcel

  2. The thesis of stages fourteen years later

    Science.gov (United States)

    Beeby, C. E.

    1980-12-01

    The author indicates the changes and additions he would make to his book ` The Quality of Education in Developing Countries' (1966) if he were re-writing it in 1980. He would make clearer that his primary interest is in a continuum of change, the process of growth of a school system, and that the `stages' are only a convenient non-mathematical artifact to make the thesis more useful to administrators and planners. In the light of more recent developments and experiences, he now gives new stress to the pluralism of objectives at the stage of Meaning, and discusses the political, social, cultural and financial reasons why a country may choose not to take the difficult step from stage III to stage IV. Recent forms of alternative education, particularly those embodying plans for lifelong education, offer some hope of bypassing his thesis of stages. More consideration is given to constraints other than that of teacher qualification, though the difficulty of changing the skills, habits, attitudes and purposes in the teaching profession remain the chief obstacle to qualitative growth. Particular attention is paid to `crash' programmes where processes that are, by their very nature, successive are compressed into simultaneous or almost simultaneous ones. Some implications of the thesis of stages for teacher training are briefly dealt with. Regarding the application of the thesis to secondary education, he maintains that a better model of growth would be one based on the capacity of secondary education to respond to the changing economic and social demands of the community. Finally, he suggests three methods of testing his hypotheses and pleads that more consideration be given to building up a body of educational, theory based on the experience of developing countries over the past three decades.

  3. Exploration of Visible-Light Photocatalysis in Heterocycle Synthesis and Functionalization: Reaction Design and Beyond.

    Science.gov (United States)

    Chen, Jia-Rong; Hu, Xiao-Qiang; Lu, Liang-Qiu; Xiao, Wen-Jing

    2016-09-20

    pyridazine derivatives in good yields and selectivity. Moreover, we have demonstrated that this photocatalysis can serve as a mild and highly selective tool for direct functionalization of heterocycles because of its powerful capability to controllably generate diverse reactive intermediates under mild reaction conditions. Guided by the fundamental principles of photocatalysis and the redox properties of the photocatalysts, we successfully developed an array of dual-catalyst systems by combining the photocatalysts with palladium, nickel, or amine, enabling efficient and selective coupling reactions. An intriguing phototandem catalytic system using a single photocatalyst was also identified for the development of cascade reactions. Notably, some of the newly developed methodologies have also been successfully utilized for late-stage modification of biologically active natural compounds and complex molecules and as key steps for formal synthesis of natural products. This Account presents a panoramic view and the logic of our recent contributions to the design, development, and application of photocatalytic systems and reactions that provide not only methods for the efficient synthesis of heterocycles but also useful insights into the exploration of new photochemical reactions.

  4. Sugarcane bagasse gasification: Global reaction mechanism of syngas evolution

    International Nuclear Information System (INIS)

    Ahmed, I.I.; Gupta, A.K.

    2012-01-01

    Highlights: ► Gasification of sugarcane bagasse has been investigated using a semi batch reactor. ► Global reaction mechanism combining pyrolysis and gasification reactions is presented. ► High flow rates of syngas supported fragmentation and secondary reactions. ► CO flow rate increased at higher heating rates at the expense of CO 2 production. ► At high temperatures merger between pyrolysis and char gasification occurs. -- Abstract: Steam gasification of sugarcane bagasse has been investigated. A semi batch reactor with a fixed amount of sugarcane bagasse sample placed in steady flow of high temperature steam at atmospheric pressure has been used. The gasification of bagasse was examined at reactor and steam temperatures of 800, 900 and 1000 °C. The evolution of syngas flow rate and chemical composition has been monitored. The evolution of chemical composition and total flow rate of the syngas has been used to formulate a global reaction mechanism. The mechanism combines pyrolysis reaction mechanisms from the literature and steam gasification/reforming reactions. Steam gasification steps include steam–hydrocarbons reforming, char gasification and water gas shift reactions. Evidence of fragmentation, secondary ring opening reactions and tertiary reactions resulting in formation of gaseous hydrocarbons is supported by higher flow rates of syngas and hydrogen at high heating rates and high reactor temperatures. Increase in carbon monoxide flow rate at the expense of carbon dioxide flow rate with the increase in reactor temperature has been observed. This increase in the ratio of CO/CO 2 flow rate confirms the production of CO and CO 2 from the competing reaction routes. At 1000 °C gasification a total merging between the pyrolysis step and the char gasification step has been observed. This is attributed to acceleration of char gasification reactions and acceleration of steam–hydrocarbons reforming reactions. These hydrocarbons are the precursors to

  5. TRIMOLECULAR REACTIONS OF URANIUM HEXAFLUORIDE WITH WATER

    Energy Technology Data Exchange (ETDEWEB)

    Westbrook, M.; Becnel, J.; Garrison, S.

    2010-02-25

    The hydrolysis reaction of uranium hexafluoride (UF{sub 6}) is a key step in the synthesis of uranium dioxide (UO{sub 2}) powder for nuclear fuels. Mechanisms for the hydrolysis reactions are studied here with density functional theory and the Stuttgart small-core scalar relativistic pseudopotential and associated basis set for uranium. The reaction of a single UF{sub 6} molecule with a water molecule in the gas phase has been previously predicted to proceed over a relatively sizeable barrier of 78.2 kJ {center_dot} mol{sup -1}, indicating this reaction is only feasible at elevated temperatures. Given the observed formation of a second morphology for the UO{sub 2} product coupled with the observations of rapid, spontaneous hydrolysis at ambient conditions, an alternate reaction pathway must exist. In the present work, two trimolecular hydrolysis mechanisms are studied with density functional theory: (1) the reaction between two UF{sub 6} molecules and one water molecule, and (2) the reaction of two water molecules with a single UF{sub 6} molecule. The predicted reaction of two UF{sub 6} molecules with one water molecule displays an interesting 'fluorine-shuttle' mechanism, a significant energy barrier of 69.0 kJ {center_dot} mol{sup -1} to the formation of UF{sub 5}OH, and an enthalpy of reaction ({Delta}H{sub 298}) of +17.9 kJ {center_dot} mol{sup -1}. The reaction of a single UF{sub 6} molecule with two water molecules displays a 'proton-shuttle' mechanism, and is more favorable, having a slightly lower computed energy barrier of 58.9 kJ {center_dot} mol{sup -1} and an exothermic enthalpy of reaction ({Delta}H{sub 298}) of -13.9 kJ {center_dot} mol{sup -1}. The exothermic nature of the overall UF{sub 6} + 2 {center_dot} H{sub 2}O trimolecular reaction and the lowering of the barrier height with respect to the bimolecular reaction are encouraging; however, the sizable energy barrier indicates further study of the UF{sub 6} hydrolysis reaction

  6. Possibility of the Nonenzymatic Browning (Maillard) Reaction in the ISM

    Science.gov (United States)

    Jalbout, Abraham F.; Shipar, M. Abul Haider

    2008-04-01

    The possibility of the occurrence of the nonenzymatic browning reaction in the gaseous phase in the interstellar medium has been investigated by using Density Functional Theory computations. Mechanisms for the reactions between formaldehyde ( Fald) + glycine ( Gly), Fald + NH 3 and Fald + methylamine ( MeAm) have been proposed, and the possibility of the formation of different compounds in the proposed mechanisms has been evaluated through calculating the Gibb's free energy changes for different steps of the reaction, by following the total mass balance. The Fald + Gly reaction under basic conditions is found as the most favorable for producing 1-methyl-amino methene or 1-methyl-amino methelene ( MAM). The reaction under acidic conditions is found to be the least favorable for producing MAM. The Fald + NH 3 reaction is found to be plausible for the production of MeAm, which can participate by reaction with Fald, resulting in the formation of MAM.

  7. Seven steps towards a PhD in psychiatry.

    Science.gov (United States)

    Molina-Ruiz, Rosa María

    2016-12-01

    The present review aims to describe the main steps for completing a psychiatric PhD thesis with success. A selective review of the literature and the author's experience as a psychiatrist completing a PhD. Deciding upon a topic, choosing a mentor, organising your time, persevering and remaining motivated are the key elements. Preparedness and diligence lead the way towards a PhD. This advice is also relevant for those undertaking research at any stage of their career. © The Royal Australian and New Zealand College of Psychiatrists 2016.

  8. A green Hunsdiecker reaction of cinnamic acids

    Energy Technology Data Exchange (ETDEWEB)

    Sodre, Leonardo R.; Esteves, Pierre M.; Mattos, Marcio C. S. de, E-mail: pesteves@iq.ufrj.br, E-mail: mmattos@iq.ufrj.br [Universidade Federal do Rio de Janeiro (UFRJ), RJ (Brazil). Instituto de Quimica. Departamento de Quimica

    2013-02-15

    Tribromo- and trichloroisocyanuric acids react with cinnamic acids in NaOH/H{sub 2}O/Et{sub 2}O at room temperature to produce (E)-2-halostyrenes regioselectively in 25-95% yield. Mechanism studies using Hammett correlations and DFT (density functional theory) calculations have shown that this reaction has as rate determining step the electrophilic addition of chlorine atom to the double bond. (author)

  9. Multivariate statistical analysis of a multi-step industrial processes

    DEFF Research Database (Denmark)

    Reinikainen, S.P.; Høskuldsson, Agnar

    2007-01-01

    Monitoring and quality control of industrial processes often produce information on how the data have been obtained. In batch processes, for instance, the process is carried out in stages; some process or control parameters are set at each stage. However, the obtained data might not be utilized....... This approach will show how the process develops from a data point of view. The procedure is illustrated on a relatively simple industrial batch process, but it is also applicable in a general context, where knowledge about the variables is available....... efficiently, even if this information may reveal significant knowledge about process dynamics or ongoing phenomena. When studying the process data, it may be important to analyse the data in the light of the physical or time-wise development of each process step. In this paper, a unified approach to analyse...

  10. A step-by-step guide to office-based sperm retrieval for obstructive azoospermia.

    Science.gov (United States)

    Coward, Robert M; Mills, Jesse N

    2017-08-01

    A variety of surgical options exists for sperm retrieval in the setting of obstructive azoospermia (OA). With appropriate preparation, the majority of these techniques can safely be performed in the office with local anesthesia and with or without monitored anesthesia care (MAC). The available techniques include percutaneous options such as percutaneous epididymal sperm aspiration (PESA) and testicular sperm aspiration (TESA), as well as open techniques that include testicular sperm extraction (TESE) and microsurgical epididymal sperm aspiration (MESA). In addition to providing a step-by-step description of each available approach, we introduce and describe a new technique for sperm retrieval for OA called minimally invasive epididymal sperm aspiration (MIESA). The MIESA utilizes a tiny keyhole incision, and the epididymis is exposed without testicular delivery. Epididymal aspiration is performed in the style of MESA, except using loupe magnification rather than an operating microscope. MIESA is a safe, office-based procedure in which millions of motile sperm can be retrieved for cryopreservation. While we prefer the MIESA technique for OA, there remain distinct advantages of each open and percutaneous approach. In the current era of assisted reproductive technology, sperm retrieval rates for OA should approach 100% regardless of the technique. This reference provides a roadmap for both advanced and novice male reproductive surgeons to guide them through every stage of sperm retrieval for OA, including preoperative evaluation, patient selection, procedural techniques, and complications. With the incredible advances in in vitro fertilization (IVF), combined with innovative surgical treatment for male factor infertility in recent years, OA is no longer a barrier for men to become biologic fathers.

  11. High energy photons production in nuclear reactions

    International Nuclear Information System (INIS)

    Nifenecker, H.; Pinston, J.A.

    1990-01-01

    Hard photon production, in nucleus-nucleus collisions, were studied at beam energies between 10 and 125 MeV. The main characteristics of the photon emission are deduced. They suggest that the neutron-proton collisions in the early stage of the reaction are the main source of high energy gamma-rays. An overview of the theoretical approaches is given and compared with experimental results. Theoretical attempts to include the contribution of charged pion exchange currents to photon production, in calculations of proton-nucleus-gamma and nucleus-nucleus-gamma reactions, showed suitable fitting with experimental data

  12. Nuclear Cryogenic Propulsion Stage

    Science.gov (United States)

    Houts, Michael G.; Borowski, S. K.; George, J. A.; Kim, T.; Emrich, W. J.; Hickman, R. R.; Broadway, J. W.; Gerrish, H. P.; Adams, R. B.

    2012-01-01

    The fundamental capability of Nuclear Thermal Propulsion (NTP) is game changing for space exploration. A first generation Nuclear Cryogenic Propulsion Stage (NCPS) based on NTP could provide high thrust at a specific impulse above 900 s, roughly double that of state of the art chemical engines. Characteristics of fission and NTP indicate that useful first generation systems will provide a foundation for future systems with extremely high performance. The role of the NCPS in the development of advanced nuclear propulsion systems could be analogous to the role of the DC-3 in the development of advanced aviation. Progress made under the NCPS project could help enable both advanced NTP and advanced NEP.

  13. Nuclear reaction studies

    International Nuclear Information System (INIS)

    Alexander, J.M.; Lacey, R.A.

    1994-01-01

    Research focused on the statistical and dynamical properties of ''hot'' nuclei formed in symmetric heavy-ion reactions. Theses included ''flow'' measurements and the mechanism for multifragment disassembly. Model calculations are being performed for the reactions C+C, Ne+Al, Ar+Sc, Kr+Nb, and Xe+La. It is planned to study 40 Ar reactions from 27 to 115 MeV/nucleon. 2 figs., 41 refs

  14. A Control Method Based on Modal Transformation for Biped Robots to Climb Unknown Steps

    Science.gov (United States)

    Shimmyo, Shuhei; Nakazato, Miki; Mikami, Kei; Sato, Tomoya; Sakaino, Sho; Ohnishi, Kouhei

    This paper proposes a control method based on modal transformation for biped robots to climb unknown steps. This method is able to control the foot position of the biped robot and the ground reaction force acting in vertical direction when the biped robot climbs unknown steps in a double-support phase. The effectiveness of the proposed method is confirmed by simulation and experimental results.

  15. Unexpected Reaction Pathway for butyrylcholinesterase-catalyzed inactivation of “hunger hormone” ghrelin

    Science.gov (United States)

    Yao, Jianzhuang; Yuan, Yaxia; Zheng, Fang; Zhan, Chang-Guo

    2016-02-01

    Extensive computational modeling and simulations have been carried out, in the present study, to uncover the fundamental reaction pathway for butyrylcholinesterase (BChE)-catalyzed hydrolysis of ghrelin, demonstrating that the acylation process of BChE-catalyzed hydrolysis of ghrelin follows an unprecedented single-step reaction pathway and the single-step acylation process is rate-determining. The free energy barrier (18.8 kcal/mol) calculated for the rate-determining step is reasonably close to the experimentally-derived free energy barrier (~19.4 kcal/mol), suggesting that the obtained mechanistic insights are reasonable. The single-step reaction pathway for the acylation is remarkably different from the well-known two-step acylation reaction pathway for numerous ester hydrolysis reactions catalyzed by a serine esterase. This is the first time demonstrating that a single-step reaction pathway is possible for an ester hydrolysis reaction catalyzed by a serine esterase and, therefore, one no longer can simply assume that the acylation process must follow the well-known two-step reaction pathway.

  16. Sleeve reaction chamber system

    Science.gov (United States)

    Northrup, M Allen [Berkeley, CA; Beeman, Barton V [San Mateo, CA; Benett, William J [Livermore, CA; Hadley, Dean R [Manteca, CA; Landre, Phoebe [Livermore, CA; Lehew, Stacy L [Livermore, CA; Krulevitch, Peter A [Pleasanton, CA

    2009-08-25

    A chemical reaction chamber system that combines devices such as doped polysilicon for heating, bulk silicon for convective cooling, and thermoelectric (TE) coolers to augment the heating and cooling rates of the reaction chamber or chambers. In addition the system includes non-silicon-based reaction chambers such as any high thermal conductivity material used in combination with a thermoelectric cooling mechanism (i.e., Peltier device). The heat contained in the thermally conductive part of the system can be used/reused to heat the device, thereby conserving energy and expediting the heating/cooling rates. The system combines a micromachined silicon reaction chamber, for example, with an additional module/device for augmented heating/cooling using the Peltier effect. This additional module is particularly useful in extreme environments (very hot or extremely cold) where augmented heating/cooling would be useful to speed up the thermal cycling rates. The chemical reaction chamber system has various applications for synthesis or processing of organic, inorganic, or biochemical reactions, including the polymerase chain reaction (PCR) and/or other DNA reactions, such as the ligase chain reaction.

  17. Sodium-concrete reactions

    International Nuclear Information System (INIS)

    Gadd, P.G.

    1982-09-01

    Reaction products of all the major constituents of commercial concrete with liquid sodium have been identified using X-Ray Powder Diffraction. Eight different aggregate materials were chosen to represent the main rock classes available and Ordinary Portland Cement was used throughout. A Differential Thermal Analysis apparatus which enabled continuous stirring of the reactants was designed to improve contact between the powdered concrete components and the liquid sodium. Heats of reaction were calculated from peak areas, the apparatus having been calibrated using reactions of sodium with simple binary oxides whose heats of reaction were known. The heat evolution from aggregates was rationalised on the basis of their mineralogical composition, thus providing a means of choosing an optimum aggregate for use in the concrete of a LMFBR. The reaction of SiO 2 with liquid sodium was shown to depend on the oxygen concentration of the sodium. Reaction products are identified. The reaction of Al 2 O 3 with sodium has been shown also to depend on the oxygen concentration. Reaction products are identified. The evolution of hydrogen during a sodium-cement reaction has been studied using an electrochemical hydrogen meter and the penetration of the liquid metal into cement blocks was also investigated. (author)

  18. Tattoo reaction: Case series

    Directory of Open Access Journals (Sweden)

    Muneer Mohamed

    2018-04-01

    Full Text Available Tattoo is going to be a very common practice especially among young people and we are witnessing a gradual increase of numerous potential complications to tattoo placement which are often seen by physicians, but generally unknown to the public. The most common skin reactions to tattoo include a transient acute inflammatory reaction due to trauma of the skin with needles and medical complications such as superficial and deep local infections, systemic infections, allergic contact dermatitis, photodermatitis, granulomatous and lichenoid reactions, and skin diseases localized on tattooed area (eczema, psoriasis, lichen, and morphea. In this series we present three cases of tattoo reaction.

  19. Method for Selection of Solvents for Promotion of Organic Reactions

    DEFF Research Database (Denmark)

    Gani, Rafiqul; Jiménez-González, Concepción; Constable, David J.C.

    2005-01-01

    estimates of thermodynamic properties to generate a knowledge base of reaction, solvent and environment related properties that directly or indirectly influence the rate and/or conversion of a given reaction. Solvents are selected using a rules-based procedure where the estimated reaction-solvent properties...... is to produce, for a given reaction, a short list of chemicals that could be considered as potential solvents, to evaluate their performance in the reacting system, and, based on this, to rank them according to a scoring system. Several examples of application are given to illustrate the main features and steps...

  20. Optimization of multi-stage pyrolysis

    International Nuclear Information System (INIS)

    Oyedun, Adetoyese Olajire; Lam, Ka Leung; Gebreegziabher, Tesfaldet; Hui, Chi Wai

    2013-01-01

    Pyrolysis process is considered as a beneficial option in waste treatment largely due to the products generated and the energy recovery when compared to other methods. In the conventional pyrolysis process, heat is continually supplied to the reactor until the final pyrolysis temperature is attained. The reactor is then maintained isothermally at this temperature until the pyrolysis is completed. This technique does not take into consideration the mechanism of the pyrolysis which involves both exothermic and endothermic reaction and the opportunity of gaining some processing benefits is often ignored. Multi-stage pyrolysis which is an approach to carry out pyrolysis with multiple heating stages in order to gain certain processing benefits has been introduced in our earlier works. 22.5% energy reduction was achieved in our past work with a 100% increase in completion time. This work therefore proposes the optimization of the operating parameters in multi-stage pyrolysis in order to limit the increase in completion time and also reduces the overall energy. This innovative approach can achieve a range of 24.7%–37.9% reduction in energy usage with 37%–50% increase in completion time depending on the heating rate for each heating stages. This approach has also been used for charcoal production