Electronic health records in an occupational health setting-Part II. Global deployment.

PubMed

Bey, Jean M; de Magalhães, Josiane S; Bojórquez, Lorena; Lin, Karen

2013-03-01

Electronic medical record systems are being used by more multi-national corporations. This article describes one corporation's considerations and process in successfully deploying a global electronic medical record system to international facilities in Brazil, Mexico, Singapore, and Taiwan. This article summarizes feedback from the experiences of occupational health nurse superusers in these countries. Copyright 2013, SLACK Incorporated.

Syllabus in Trade Electricity-Electronics. Section II. Trade Electricity.

ERIC Educational Resources Information Center

New York State Education Dept., Albany. Bureau of Occupational Education Curriculum Development.

This second section of a three-part syllabus for a flexible curriculum in trade electricity-electronics contains four semi-independent units: (1) Advanced Electricity, (2) Residential and Commercial Wiring, (3) Industrial Electricity, and (4) Motor Controls. Introductory sections describe development of the curriculum, outline the total trade…

Modifying the electronic and optical properties of carbon nanotubes

NASA Astrophysics Data System (ADS)

Kinder, Jesse M.

The intrinsic electronic and optical properties of carbon nanotubes make them promising candidates for circuit elements and LEDs in nanoscale devices. However, applied fields and interactions with the environment can modify these intrinsic properties. This dissertation is a theoretical study of perturbations to an ideal carbon nanotube. It illustrates how transport and optical properties of carbon nanotubes can be adversely affected or intentionally modified by the local environment. The dissertation is divided into three parts. Part I analyzes the effect of a transverse electric field on the single-electron energy spectrum of semiconducting carbon nanotubes. Part II analyzes the effect of the local environment on selection rules and decay pathways relevant to dark excitons. Part III is a series of 26 appendices. Two different models for a transverse electric field are introduced in Part I. The first is a uniform field perpendicular to the nanotube axis. This model suggests the field has little effect on the band gap until it exceeds a critical value that can be tuned with strain or a magnetic field. The second model is a transverse field localized to a small region along the nanotube axis. The field creates a pair of exponentially localized bound states but has no effect on the band gap for particle transport. Part II explores the physics of dark excitons in carbon nanotubes. Two model calculations illustrate the effect of the local environment on allowed optical transitions and nonradiative recombination pathways. The first model illustrates the role of inversion symmetry in the optical spectrum. Broken inversion symmetry may explain low-lying peaks in the exciton spectrum of boron nitride nanotubes and localized photoemission around impurities and interfaces in carbon nanotubes. The second model in Part II suggests that free charge carriers can mediate an efficient nonradiative decay process for dark excitons in carbon nanotubes. The appendices in Part III provide background material and details of calculations relevant to the main text. These appendices may be useful to researchers new to the study of carbon nanotubes.

Today's Personal Computers: Products for Every Need--Part II.

ERIC Educational Resources Information Center

Personal Computing, 1981

1981-01-01

Looks at microcomputers manufactured by Altos Computer Systems, Cromemco, Exidy, Intelligent Systems, Intertec Data Systems, Mattel, Nippon Electronics, Northstar, Personal Micro Computers, and Sinclair. (Part I of this article, examining other computers, appeared in the May 1981 issue.) Journal availability: Hayden Publishing Company, 50 Essex…

Materials and Fabrication Methods II. A Study Guide of the Science and Engineering Technician Curriculum.

ERIC Educational Resources Information Center

Lindberg, Andrew; Bay, Robert

This study guide is part of a program of studies entitled Science and Engineering Technician (SET) Curriculum. The SET Curriculum integrates elements from the disciplines of chemistry, physics, mathematics, mechanical technology, and electronic technology with the objective of training technicians in the use of electronic instruments and their…

Technical Design Report for the FACET-II Project at SLAC National Accelerator Laboratory

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

None, None

Electrons can “surf” on waves of plasma – a hot gas of charged particles – gaining very high energies in very short distances. This approach, called plasma wakefield acceleration, has the potential to dramatically shrink the size and cost of particle accelerators. Research at the SLAC National Accelerator Laboratory has demonstrated that plasmas can provide 1,000 times the acceleration in a given distance compared with current technologies. Developing revolutionary and more efficient acceleration techniques that allow for an affordable high-energy collider has been the focus of FACET, a National User Facility at SLAC. FACET used part of SLAC’s two-mile-long linearmore » accelerator to generate high-density beams of electrons and their antimatter counterparts, positrons. Research into plasma wakefield acceleration was the primary motivation for constructing FACET. In April 2016, FACET operations came to an end to make way for the second phase of SLAC’s x-ray laser, the LCLS-II, which will use part of the tunnel occupied by FACET. FACET-II is a new test facility to provide the unique capability to develop advanced acceleration and coherent radiation techniques with high-energy electron and positron beams. FACET-II represents a major upgrade over current FACET capabilities and the breadth of the potential research program makes it truly unique.« less

Copper and the oxidation of hemoglobin: a comparison of horse and human hemoglobins.

PubMed

Rifkind, J M; Lauer, L D; Chiang, S C; Li, N C

1976-11-30

Oxidation studies of hemoglobin by Cu(II) indicate that for horse hemoglobin, up to a Cu(II)/heme molar ratio of 0.5, all of the Cu(II) added is used to rapidly oxidize the heme. On the other hand, most of the Cu(II) added to human hemoglobin at low Cu(II)/heme molar ratios is unable to oxidize the heme. Only at Cu(II)/heme molar ratios greater than 0.5 does the amount of oxidation per added Cu(II) approach that of horse hemoglobin. At the same time, binding studies indicate that human hemoglobin has an additional binding site involving one copper for every two hemes, which has a higher copper affinity than the single horse hemoglobin binding site. The Cu(II) oxidation of human hemoglobin is explained utilizing this additional binding site by a mechanism where a transfer of electrons cannot occur between the heme and the Cu(II) bound to the high affinity human binding site. The electron transfer must involve the Cu(II) bound to the lower affinity human hemoglobin binding site, which is similar to the only horse hemoglobin site. The involvement of beta-2 histidine in the binding of this additional copper is indicated by a comparison of the amino acid sequences of various hemoglobins which possess the additional site, with the amino acid sequences of hemoglobins which do not possess the additional site. Zn(II), Hg(II), and N-ethylmaleimide (NEM) are found to decrease the Cu(II) oxidation of hemoglobin. The sulfhydryl reagents, Hg(II) and NEM, produce a very dramatic decrease in the rate of oxidation, which can only be explained by an effect on the rate for the actual transfer of electrons between the Cu(II) and the Fe(II). The effect of Zn(II) is much smaller and can, for the most part, be explained by the increased oxygen affinity, which affects the ligand dissociation process that must precede the electron transfer process.

Resonant excitation of high order modes in the 3.9 GHz cavity of the Linac Coherent Light Source

DOE PAGES

Lunin, A.; Khabiboulline, T.; Solyak, N.; ...

2018-02-06

Construction of the Linac Coherent Light Source II (LCLS-II) is underway for the world’s first hard x-ray free-electron laser. A central part of the LCLS-II project is a 4 GeV superconducting radio frequency electron linac that will operate in the continuous wave (cw) mode. The linac is segmented into four sections named as L0, L1, L2, and L3. Two 3.9 GHz cryomodules, each housing of eight third-harmonic cavities similar to the cavities developed for the European X-ray Free Electron Laser (XFEL), will be used in section L1 of the linac for linearizing the longitudinal beam profile. Here in this paper, we presentmore » a study of trapped high order modes (HOMs) excited by a cw electron beam in the third-harmonic cavities of the LCLS-II linac. A detailed comparison of the original XFEL design and the LCLS-II design with a modified end group is performed in order to estimate the effect of a reduced beam pipe aperture on the efficiency of HOM damping. Furthermore, we apply a statistical analysis of the eigenmode spectrum for the estimation of the probability of resonant HOM losses and influence of HOMs on beam dynamics.« less

Resonant excitation of high order modes in the 3.9 GHz cavity of the Linac Coherent Light Source

NASA Astrophysics Data System (ADS)

Lunin, A.; Khabiboulline, T.; Solyak, N.; Sukhanov, A.; Yakovlev, V.

2018-02-01

Construction of the Linac Coherent Light Source II (LCLS-II) is underway for the world's first hard x-ray free-electron laser. A central part of the LCLS-II project is a 4 GeV superconducting radio frequency electron linac that will operate in the continuous wave (cw) mode. The linac is segmented into four sections named as L 0 , L 1 , L 2 , and L 3 . Two 3.9 GHz cryomodules, each housing of eight third-harmonic cavities similar to the cavities developed for the European X-ray Free Electron Laser (XFEL), will be used in section L 1 of the linac for linearizing the longitudinal beam profile. In this paper, we present a study of trapped high order modes (HOMs) excited by a cw electron beam in the third-harmonic cavities of the LCLS-II linac. A detailed comparison of the original XFEL design and the LCLS-II design with a modified end group is performed in order to estimate the effect of a reduced beam pipe aperture on the efficiency of HOM damping. Furthermore, we apply a statistical analysis of the eigenmode spectrum for the estimation of the probability of resonant HOM losses and influence of HOMs on beam dynamics.

A Multidisciplinary PBL Robot Control Project in Automation and Electronic Engineering

ERIC Educational Resources Information Center

Hassan, Houcine; Domínguez, Carlos; Martínez, Juan-Miguel; Perles, Angel; Capella, Juan-Vicente; Albaladejo, José

2015-01-01

This paper presents a multidisciplinary problem-based learning (PBL) project consisting of the development of a robot arm prototype and the implementation of its control system. The project is carried out as part of Industrial Informatics (II), a compulsory third-year course in the Automation and Electronic Engineering (AEE) degree program at the…

Change in equilibrium position of misfit dislocations at the GaN/sapphire interface by Si-ion implantation into sapphire. II. Electron energy loss spectroscopic study

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

Lee, Sung Bo, E-mail: bolee@snu.ac.kr; Han, Heung Nam, E-mail: hnhan@snu.ac.kr; Kim, Young-Min

In Part I, we have shown that the addition of Si into sapphire by ion implantationmakes the sapphire substrate elastically softer than for the undoped sapphire. The more compliant layer of the Si-implanted sapphire substrate can absorb the misfit stress at the GaN/sapphire interface, which produces a lower threading-dislocation density in the GaN overlayer. Here in Part II, based on experimental results by electron energy loss spectroscopy and a first-principle molecular orbital calculation in the literature, we suggest that the softening effect of Si results from a reduction of ionic bonding strength in sapphire (α-Al{sub 2}O{sub 3}) with the substitutionmore » of Si for Al.« less

NOSC/ONR Robotics Bibliography (1961-1981).

DTIC Science & Technology

1982-09-01

28, 6 Dec., 1979 @, p4 "DEFENSE EQUIPMENT FIRM TRAINS ROBOT TO PERFORM CRAFTSMAN-SKILLED TASK", Industrial Engineering, vol 13, no 5, May 1981 @, p90...1974 @, pCI-I-8 Gupton, J. A. Jr., "BUILD THIS UNICORN -i ROBOT PART I", Radio-Electronics, vol 51, no 8, 1980 @, p 3 7 ,4 1 ,76 Gupton, J. A. Jr...34BUILD THIS UNICORN -i ROBOT PART II", Radio-Electronics, vol 51, no 9, Sept. 1980 @, p55-8 Gupton, J. A., Jr., "TALK TO A TURTLE; BUILD A COMPUTER

Charcoal Regeneration. Part 1. Mechanism of TNT Adsorption

DTIC Science & Technology

1977-11-01

cycle and particle size 29 6 Electron spectra of virgin FS300 as received 30 ii=_ 7 Electron spectrum of TNT standard 31 8 Electron spectrum of TNT in...ground in a mortar and pestle and passed through a series of US standard sieves. The ground charcoal passing through a 325 sieve (average particle...every case were crushed manually in a mortar and pestle and dis- persed ultrasonically in order to obtain a dispersion suitable for measurement. Mass

Electronic Noise and Fluctuations in Solids

NASA Astrophysics Data System (ADS)

Kogan, Sh.

2008-07-01

Preface; Part I. Introduction. Some Basic Concepts of the Theory of Random Processes: 1. Probability density functions. Moments. Stationary processes; 2. Correlation function; 3. Spectral density of noise; 4. Ergodicity and nonergodicity of random processes; 5. Random pulses and shot noise; 6. Markov processes. General theory; 7. Discrete Markov processes. Random telegraph noise; 8. Quasicontinuous (Diffusion-like) Markov processes; 9. Brownian motion; 10. Langevin approach to the kinetics of fluctuations; Part II. Fluctuation-Dissipation Relations in Equilibrium Systems: 11. Derivation of fluctuation-dissipation relations; 12. Equilibrium noise in quasistationary circuits. Nyquist theorem; 13. Fluctuations of electromagnetic fields in continuous media; Part III. Fluctuations in Nonequilibrium Gases: 14. Some basic concepts of hot-electrons' physics; 15. Simple model of current fluctuations in a semiconductor with hot electrons; 16. General kinetic theory of quasiclassical fluctuations in a gas of particles. The Boltzmann-Langevin equation; 17. Current fluctuations and noise temperature; 18. Current fluctuations and diffusion in a gas of hot electrons; 19. One-time correlation in nonequilibrium gases; 20. Intervalley noise in multivalley semiconductors; 21. Noise of hot electrons emitting optical phonons in the streaming regime; 22. Noise in a semiconductor with a postbreakdown stable current filament; Part IV. Generation-recombination noise: 23. G-R noise in uniform unipolar semiconductors; 24. Noise produced by recombination and diffusion; Part V. Noise in quantum ballistic systems: 25. Introduction; 26. Equilibrium noise and shot noise in quantum conductors; 27. Modulation noise in quantum point contacts; 28. Transition from a ballistic conductor to a macroscopic one; 29. Noise in tunnel junctions; Part VI. Resistance noise in metals: 30. Incoherent scattering of electrons by mobile defects; 31. Effect of mobile scattering centers on the electron interference pattern; 32. Fluctuations of the number of diffusing scattering centers; 33. Temperature fluctuations and the corresponding noise; Part VII. Noise in strongly disordered conductors: 34. Basic ideas of the percolation theory; 35. Resistance fluctuations in percolation systems. 36. Experiments; Part VIII. Low-frequency noise with an 1/f-type spectrum and random telegraph noise: 37. Introduction; 38. Some general properties of 1/f noise; 39. Basic models of 1/f noise; 40./f noise in metals; 41. Low-frequency noise in semiconductors; 42. Magnetic noise in spin glasses and some other magnetic systems; 43. Temperature fluctuations as a possible source of 1/f noise; 44. Random telegraph noise; 45. Fluctuations with 1/f spectrum in other systems; 46. General conclusions on 1/f noise; Part IX. Noise in Superconductors and Superconducting Structures: 47. Noise in Josephson junctions; 48. Noise in type II superconductors; References; Subject index.

An environment-dependent semi-empirical tight binding model suitable for electron transport in bulk metals, metal alloys, metallic interfaces, and metallic nanostructures. II. Application—Effect of quantum confinement and homogeneous strain on Cu conductance

NASA Astrophysics Data System (ADS)

Hegde, Ganesh; Povolotskyi, Michael; Kubis, Tillmann; Charles, James; Klimeck, Gerhard

2014-03-01

The Semi-Empirical tight binding model developed in Part I Hegde et al. [J. Appl. Phys. 115, 123703 (2014)] is applied to metal transport problems of current relevance in Part II. A systematic study of the effect of quantum confinement, transport orientation, and homogeneous strain on electronic transport properties of Cu is carried out. It is found that quantum confinement from bulk to nanowire boundary conditions leads to significant anisotropy in conductance of Cu along different transport orientations. Compressive homogeneous strain is found to reduce resistivity by increasing the density of conducting modes in Cu. The [110] transport orientation in Cu nanowires is found to be the most favorable for mitigating conductivity degradation since it shows least reduction in conductance with confinement and responds most favorably to compressive strain.

The nature of the excited state of the reaction center of photosystem II of green plants: A high-resolution fluorescence spectroscopy study

PubMed Central

Peterman, Erwin J. G.; van Amerongen, Herbert; van Grondelle, Rienk; Dekker, Jan P.

1998-01-01

We studied the electronically excited state of the isolated reaction center of photosystem II with high-resolution fluorescence spectroscopy at 5 K and compared the obtained spectral features with those obtained earlier for the primary electron donor. The results show that there is a striking resemblance between the emitting and charge-separating states in the photosystem II reaction center, such as a very similar shape of the phonon wing with characteristic features at 19 and 80 cm−1, almost identical frequencies of a number of vibrational modes, a very similar double-Gaussian shape of the inhomogeneous distribution function, and relatively strong electron-phonon coupling for both states. We suggest that the emission at 5 K originates either from an exciton state delocalized over the inactive branch of the photosystem or from a fraction of the primary electron donor that is long-lived at 5 K. The latter possibility can be explained by a distribution of the free energy difference of the primary charge separation reaction around zero. Both possibilities are in line with the idea that the state that drives primary charge separation in the reaction center of photosystem II is a collective state, with contributions from all chlorophyll molecules in the central part of the complex. PMID:9600929

Electrical/Electronic Technology (Energy/Power). Industrial Arts, Senior High--Level II. North Dakota Senior High Industrial Arts Curriculum Guides.

ERIC Educational Resources Information Center

Lawrence, Allen; And Others

This course guide for an electrical/electronic technology course is one of four developed for the energy/power area in the North Dakota senior high industrial arts education program. (Eight other guides are available for two other areas of Industrial Arts--graphic communications and production.) Part 1 provides such introductory information as a…

Monitoring the Durability Performance of Concrete in Nuclear Waste Containment. Technical Progress Report No. 3

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

Ulm, Franz-Josef

2000-03-31

OAK-B135 Monitoring the Durability Performance of Concrete in Nuclear Waste Containment. Technical Progress Report No. 3(NOTE: Part II A item 1 indicates ''PAPER'', but a report is attached electronically)

Ultrastructural characters of the spermatozoon of the cestode Corallobothrium solidum Fritsch, 1886 (Cestoda: Proteocephalidea), a parasite of the electric catfish Malapterurus electricus.

PubMed

Brunanská, Magdaléna; Scholz, Tomás; Ibraheem, Mohammed Hassan

2004-12-01

The fine structure of the mature spermatozoon of the corallobothriine tapeworm Corallobothrium solidum Fritsch, 1886 (Cestoda: Proteocephalidea) from the electric catfish Malapterurus electricus from the Nile River in Egypt was studied by transmission electron microscopy for the first time. The filiform spermatozoon of C. solidum contains two axonemes of unequal length and a typical 9 + "1" trepaxonematan pattern. A single helicoidal crested body (30-200 nm thick) is localized at the anterior extremity of the gamete. The cortical microtubules line the periphery of the cell, largely parallel to the long axis of the spermatozoon and exhibiting signs of twisting at the beginning of region II. The nucleus, in the form of an electron-dense (largely in gametes of testes) and/or fibrous cord (largely in gametes from male reproductive ducts and seminal vesicle), coils in a spiral through the middle part (region III) of the spermatozoon. The cytoplasm contains electron-dense granules in regions II, III and partly in region IV. The cytoplasm of some spermatozoa exhibits an apparently higher electron-density at the end of the nucleated region (III), and continuously toward the middle part of region IV. The anterior and posterior extremities of the spermatozoa have a single axoneme. The ultrastructural features of the mature spermatozoon of C. solidum mostly coincide with those of the spermatozoon of other proteocephalideans, especially the gangesiine Electrotaenia malopteruri parasitizing the same host.

Online beam energy measurement of Beijing electron positron collider II linear accelerator

NASA Astrophysics Data System (ADS)

Wang, S.; Iqbal, M.; Liu, R.; Chi, Y.

2016-02-01

This paper describes online beam energy measurement of Beijing Electron Positron Collider upgraded version II linear accelerator (linac) adequately. It presents the calculation formula, gives the error analysis in detail, discusses the realization in practice, and makes some verification. The method mentioned here measures the beam energy by acquiring the horizontal beam position with three beam position monitors (BPMs), which eliminates the effect of orbit fluctuation, and is much better than the one using the single BPM. The error analysis indicates that this online measurement has further potential usage such as a part of beam energy feedback system. The reliability of this method is also discussed and demonstrated in this paper.

Online beam energy measurement of Beijing electron positron collider II linear accelerator.

PubMed

Wang, S; Iqbal, M; Liu, R; Chi, Y

2016-02-01

This paper describes online beam energy measurement of Beijing Electron Positron Collider upgraded version II linear accelerator (linac) adequately. It presents the calculation formula, gives the error analysis in detail, discusses the realization in practice, and makes some verification. The method mentioned here measures the beam energy by acquiring the horizontal beam position with three beam position monitors (BPMs), which eliminates the effect of orbit fluctuation, and is much better than the one using the single BPM. The error analysis indicates that this online measurement has further potential usage such as a part of beam energy feedback system. The reliability of this method is also discussed and demonstrated in this paper.

ASIS '99 Knowledge: Creation, Organization and Use, Part II: SIG Sessions.

ERIC Educational Resources Information Center

Proceedings of the ASIS Annual Meeting, 1999

1999-01-01

Abstracts and descriptions of Special Interest Group (SIG) sessions include such topics as: knowledge management tools, knowledge organization, information retrieval, information seeking behavior, metadata, indexing, library service for distance education, electronic books, future information workforce needs, technological developments, and…

Toward a Mechanistic Understanding of Anaerobic Nitrate-Dependent Iron Oxidation: Balancing Electron Uptake and Detoxification

PubMed Central

Carlson, Hans K.; Clark, Iain C.; Melnyk, Ryan A.; Coates, John D.

2011-01-01

The anaerobic oxidation of Fe(II) by subsurface microorganisms is an important part of biogeochemical cycling in the environment, but the biochemical mechanisms used to couple iron oxidation to nitrate respiration are not well understood. Based on our own work and the evidence available in the literature, we propose a mechanistic model for anaerobic nitrate-dependent iron oxidation. We suggest that anaerobic iron-oxidizing microorganisms likely exist along a continuum including: (1) bacteria that inadvertently oxidize Fe(II) by abiotic or biotic reactions with enzymes or chemical intermediates in their metabolic pathways (e.g., denitrification) and suffer from toxicity or energetic penalty, (2) Fe(II) tolerant bacteria that gain little or no growth benefit from iron oxidation but can manage the toxic reactions, and (3) bacteria that efficiently accept electrons from Fe(II) to gain a growth advantage while preventing or mitigating the toxic reactions. Predictions of the proposed model are highlighted and experimental approaches are discussed. PMID:22363331

From Hippocrates to HIPAA: privacy and confidentiality in emergency medicine--Part II: Challenges in the emergency department.

PubMed

Moskop, John C; Marco, Catherine A; Larkin, Gregory Luke; Geiderman, Joel M; Derse, Arthur R

2005-01-01

Part I of this article reviewed the concepts of privacy and confidentiality and described the moral and legal foundations and limits of these values in health care. Part II highlights specific privacy and confidentiality issues encountered in the emergency department (ED). Discussed first are physical privacy issues in the ED, including problems of ED design and crowding, issues of patient and staff safety, the presence of visitors, law enforcement officers, students, and other observers, and filming activities. The article then examines confidentiality issues in the ED, including protecting medical records, the duty to warn, reportable conditions, telephone inquiries, media requests, communication among health care professionals, habitual patient files, the use of patient images, electronic communication, and information about minor patients.

Monopole HOMs Dumping in the LCLS-II 1.3 GHz Structure

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

Lunin, Andrei; Khabiboulline, Timergali; Solyak, Nikolay

2017-05-01

Developing an upgrade of Linac Coherent Light Source (LCLS-II) is currently underway. The central part of LCLS-II is a continuous wave superconducting RF (CW SRF) electron linac. High order modes (HOMs) excited in SRF structures by passing beam may deteriorate beam quality and affect beam stability. In this paper we report the simulation results of monopole High Order Modes (HOM) spectrum in the 1.3 GHz accelerating structure. Optimum parameters of the HOM feedthrough are suggested for minimizing RF losses on the HOM antenna tip and for preserving an efficiency of monopole HOMs damping simultaneously.

Connectivity between electron transport complexes and modulation of photosystem II activity in chloroplasts.

PubMed

Tikhonov, Alexander N; Vershubskii, Alexey V

2017-09-01

In chloroplasts, photosynthetic electron transport complexes interact with each other via the mobile electron carriers (plastoquinone and plastocyanin) which are in surplus amounts with respect to photosystem I and photosystem II (PSI and PSII), and the cytochrome b 6 f complex. In this work, we analyze experimental data on the light-induced redox transients of photoreaction center P 700 in chloroplasts within the framework of our mathematical model. This analysis suggests that during the action of a strong actinic light, even significant attenuation of PSII [for instance, in the result of inhibition of a part of PSII complexes by DCMU or due to non-photochemical quenching (NPQ)] will not cause drastic shortage of electron flow through PSI. This can be explained by "electronic" and/or "excitonic" connectivity between different PSII units. At strong AL, the overall flux of electrons between PSII and PSI will maintain at a high level even with the attenuation of PSII activity, provided the rate-limiting step of electron transfer is beyond the stage of PQH 2 formation. Results of our study are briefly discussed in the context of NPQ-dependent mechanism of chloroplast protection against light stress.

Test of the HAPD light sensor for the Belle II Aerogel RICH

NASA Astrophysics Data System (ADS)

Yusa, Y.; Adachi, I.; Dolenec, R.; Hayata, K.; Iori, S.; Iwata, S.; Kakuno, H.; Kataura, R.; Kawai, H.; Kindo, H.; Kobayashi, T.; Korpar, S.; Krizan, P.; Kumita, T.; Mrvar, M.; Nishida, S.; Ogawa, K.; Pestotnik, R.; Santelj, L.; Sumiyoshi, T.; Tabata, M.; Yonenaga, M.

2017-12-01

The Aerogel Ring-Imaging Cherenkov detector (ARICH) is being installed in the endcap region of Belle II spectrometer to identify particles from B meson decays by detecting the Cherenkov ring image from aerogel radiators. To detect single photons, high-sensitive photon detector which has wide effective area (∼70 mm × 70 mm), a Hybrid Avalanche Photo Detector (HAPD), has been developed in a collaboration with Hamamatsu K.K. The HAPD consists of hybrid structure of a vacuum tube and an avalanche photodiode (APD). It can be operated in 1.5 T magnetic field of the spectrometer and withstands the radiation levels expected in the Belle II experiment. There are two steps of electric pulse amplification: acceleration of photo-electron in electric field in the vacuum tube part and electron avalanche in the APD part resulting in total gain of order 105. For the ARICH, we use 420 HAPDs in total. Before installing them, we performed quality assessment studies such as measurements of dark current, noise level, signal-to-noise ratio and two-dimensional scan with laser illumination. We also measured quantum efficiency of the photocathode. During the HAPD performance tests in the magnetic field, we observed very large signal pulses which cause long dead time of the readout electronics in some of the HAPDs. We have carried out a number of studies to understand this phenomenon, and have found a way to mitigate it and suppress the degradation of the ARICH performance. In this report, we will show a summary of the HAPD performance and quality assessment measurements including validation in the magnetic field for all of the HAPDs manufactured for the ARICH in the Belle II.

Media of Technological Revolution, Part II

ERIC Educational Resources Information Center

Georgetown Law Journal, 1972

1972-01-01

An overview of the development of electronic media. Governance of television both as entertainment and journalism and its relationship with broadcast advertising is discussed. Cable television, its potential for the future, and how the Federal Communications Commission must develop a new regulatory rationale to deal with new problems are…

Electronic spectra of the tetraphenylcyclobutadienecyclopentadienylnickel(II) cation and radical

DOE PAGES

Peter R. Craig; Miller, John R.; Havlas, Zdenek; ...

2016-05-02

In this study, properties of the tetraphenylcyclobutadienecyclopentadienylnickel(II) cation 1 and its tetra-o-fluoro derivative 1a have been measured and calculated. The B3LYP/TZP optimized geometry of the free cation 1 agrees with a single-crystal X-ray diffraction structure except that in the crystal one of the phenyl substituents is strongly twisted to permit a close-packing interaction of two of its hydrogens with a nearby BF – 4 anion. The low-energy parts of the solution electronic absorption and magnetic circular dichroism (MCD) spectra of 1 and 1a have been interpreted by comparison with TD-DFT (B3LYP/TZP) results. Reduction or pulse radiolysis lead to a neutralmore » 19-electron radical, whose visible absorption and MCD spectra have been recorded and interpreted as well. The reduction is facilitated by ~0.1 V upon going from 1 to 1a« less

Stability of Catalyzed Magnesium Hydride Nanocrystalline During Hydrogen Cycling. Part II: Microstructure Evolution

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

Zhou, Chengshang; Fang, Zhigang Zak; Bowman, Robert C.

2015-10-01

In Part I, the cyclic stabilities of the kinetics of catalyzed MgH2 systems including MgH2–TiH2, MgH2–TiMn2, and MgH2–VTiCr were investigated, showing stable kinetics at 300 °C but deteriorations of the hydrogenation kinetics at temperatures below 150 °C. The present Part II describes the characterization of uncycled and cycled catalyzed MgH2 by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and X-ray photoelectron spectroscopy (XPS) analysis. XRD analysis shows the crystallite sizes of the Mg and MgH2 significantly increased after the cycling. The mean crystallite sizes of the catalysts (TiH2 and VTiCr) increased moderately after the cycling. SEMmore » and TEM imaging were used to compare the microstructures of uncycled (as-milled) and cycled materials, revealing a drastic change of the microstructure after 100 cycles. In particular, results from energy-dispersive spectroscopy (EDS) mapping show that a change of distribution of the catalyst particles in the Mg and MgH2 phase occurred during the cycling.« less

Expression of vesicular glutamate transporters, VGluT1 and VGluT2, in axon terminals of nociceptive primary afferent fibers in the superficial layers of the medullary and spinal dorsal horns of the rat.

PubMed

Li, Jin-Lian; Fujiyama, Fumino; Kaneko, Takeshi; Mizuno, Noboru

2003-03-10

We examined immunohistochemically whether the vesicular glutamate transporters (VGluTs), VGluT1 and VGluT2, might be expressed in synaptic terminals of nociceptive primary afferent fibers within laminae I and II of the medullary and spinal dorsal horns of the rat. VGluT1 immunoreactivity (IR) was intense in the inner part of lamina II but weak in lamina I and the outer part of lamina II. VGluT2-IR was most intense in lamina I and the outer part of lamina II. Expression of VGluTs in synaptic terminals was confirmed by dual immunofluorescence histochemistry for VGluTs and synaptophysin. Expression of VGluTs in axon terminals of primary afferent fibers terminating in laminae I and II was also confirmed immunohistochemically after unilateral dorsal rhizotomy. The dual immunofluorescence histochemistry indicated expression of VGluTs in substance P (SP)-containing axon terminals in lamina I and the outer part of lamina II. Electron microscopy confirmed the coexpression of VGluTs and SP in axon terminals within laminae I and II; VGluTs was associated with round synaptic vesicles at the asymmetric synapses. It was further observed that isolectin IB4, a marker for unmyelinated axons, often bound with VGluT2-immunopositive structures but rarely with VGluT1-immunopositive structures in lamina II. Thus, the results indicated in laminae I and II of the medullary and spinal dorsal horns that both VGluT1 and VGluT2 were expressed in axon terminals of primary afferent fibers, including SP-containing nociceptive fibers and that VGluT in unmyelinated primary afferent fibers terminating in lamina II was primarily VGluT2. Copyright 2003 Wiley-Liss, Inc.

Structure-Property Relationships in Novel Materials Part I: Frustrated Magnetism and Deintercalation of Honeycomb Oxides Part II: Electron-Precise Gold Intermetallics

NASA Astrophysics Data System (ADS)

Seibel, Elizabeth M.

This thesis is a study of the structure-property relationships of novel materials, broken into two major parts. The first part, "Part I: Frustrated Magnetism and Deintercalation of Honeycomb Oxides" explores new, layered nickel oxides and their properties, specifically the synthesis, structure, magnetism, and applications of the Na3Ni 2BiO6-NaNi2BiO6-NaNi2BiO 6•1.7H2O system. These phases are of interest to the solid-state and physics communities because they display frustrated magnetism on a hexagonal lattice. Chapter 3 explores the chemistry and physics of Na 3Ni2BiO6; Chapter 4 then discusses its chemical deintercalation and subsequent hydration to form the NaNi2BiO 6-NaNi2BiO6•1.7H2O system. These phases are examples of sought-after spin-1/2 systems on a hexagonal lattice. The second part of this thesis, "Part II: Electron-Precise Gold Intermetallics" explores novel, electron-precise intermetallics in the Lanthanide-gold-pnictide ternary system. The chemistry of gold-containing solids has not been well-studied despite gold's unusual physics, motivating the study. There are three new families discussed herein. The first, found in Chapter 7, is of the type LnAuSb (Ln = Lanthanide) which are new Dirac semimetals. The work illustrates a chemical design principle that can be used to predict new Dirac Semimetals, which is important given that the field of topological materials is rapidly growing. Chapter 8 discusses materials of the type LnAuBi2, which are layered intermetallics with a high degree of magnetic anisotropy. Finally, Chapter 9 explores new phases of the form Ln 3Au3Bi4. These materials are semiconductors with high Seebeck coefficients at room temperature, indicating their potential for use as thermoelectric materials.

31 CFR 560.538 - Authorized transactions necessary and ordinarily incident to publishing.

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Solar Eclipse (1979). Part II. Initial Results for Ionization Sources, Electron Density, and Minor Neutral Constituents.

DTIC Science & Technology

1980-10-01

OH 45433 Director Commandant Office of Missile Electronic Warfare US Army Field Artillery School ATTN: DELEW-M-STO (Dr. Steven Kovel) ATTN: ATSF- CF -R...Commander Commandant US Army White Sands Missile Range US Army Field Artillery School ATTN: STEWS-PT-AL (Laurel B. Saunders) ATTN: ATSF- CF -R White Sands...Commander Defense Communications Agency US Army INSCOM/Quest Research Corporation Technical Library Center ATTN: Mr. Donald Wilmot Code 222 6845 Elm Street

Synchrotron X-ray CT characterization of titanium parts fabricated by additive manufacturing. Part II. Defects.

PubMed

Scarlett, Nicola Vivienne Yorke; Tyson, Peter; Fraser, Darren; Mayo, Sheridan; Maksimenko, Anton

2016-07-01

Synchrotron X-ray tomography (SXRT) has been applied to the study of defects within three-dimensional printed titanium parts. These parts were made using the Arcam EBM(®) (electron beam melting) process which uses powdered titanium alloy, Ti64 (Ti alloy with approximately 6%Al and 4%V) as the feed and an electron beam for the sintering/welding. The experiment was conducted on the Imaging and Medical Beamline of the Australian Synchrotron. The samples represent a selection of complex shapes with a variety of internal morphologies. Inspection via SXRT has revealed a number of defects which may not otherwise have been seen. The location and nature of such defects combined with detailed knowledge of the process conditions can contribute to understanding the interplay between design and manufacturing strategy. This fundamental understanding may subsequently be incorporated into process modelling, prediction of properties and the development of robust methodologies for the production of defect-free parts.

Dosimetric characterization and output verification for conical brachytherapy surface applicators. Part I. Electronic brachytherapy source

PubMed Central

Fulkerson, Regina K.; Micka, John A.; DeWerd, Larry A.

2014-01-01

Purpose: Historically, treatment of malignant surface lesions has been achieved with linear accelerator based electron beams or superficial x-ray beams. Recent developments in the field of brachytherapy now allow for the treatment of surface lesions with specialized conical applicators placed directly on the lesion. Applicators are available for use with high dose rate (HDR) 192Ir sources, as well as electronic brachytherapy sources. Part I of this paper will discuss the applicators used with electronic brachytherapy sources; Part II will discuss those used with HDR 192Ir sources. Although the use of these applicators has gained in popularity, the dosimetric characteristics including depth dose and surface dose distributions have not been independently verified. Additionally, there is no recognized method of output verification for quality assurance procedures with applicators like these. Existing dosimetry protocols available from the AAPM bookend the cross-over characteristics of a traditional brachytherapy source (as described by Task Group 43) being implemented as a low-energy superficial x-ray beam (as described by Task Group 61) as observed with the surface applicators of interest. Methods: This work aims to create a cohesive method of output verification that can be used to determine the dose at the treatment surface as part of a quality assurance/commissioning process for surface applicators used with HDR electronic brachytherapy sources (Part I) and 192Ir sources (Part II). Air-kerma rate measurements for the electronic brachytherapy sources were completed with an Attix Free-Air Chamber, as well as several models of small-volume ionization chambers to obtain an air-kerma rate at the treatment surface for each applicator. Correction factors were calculated using MCNP5 and EGSnrc Monte Carlo codes in order to determine an applicator-specific absorbed dose to water at the treatment surface from the measured air-kerma rate. Additionally, relative dose measurements of the surface dose distributions and characteristic depth dose curves were completed in-phantom. Results: Theoretical dose distributions and depth dose curves were generated for each applicator and agreed well with the measured values. A method of output verification was created that allows users to determine the applicator-specific dose to water at the treatment surface based on a measured air-kerma rate. Conclusions: The novel output verification methods described in this work will reduce uncertainties in dose delivery for treatments with these kinds of surface applicators, ultimately improving patient care. PMID:24506635

Redesign of the End Group in the 3.9 GHz LCLS-II Cavity

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

Lunin, Andrei; Gonin, Ivan; Khabiboulline, Timergali

Development and production of Linac Coherent Light Source II (LCLS-II) is underway. The central part of LCLS-II is a continuous wave superconducting RF (CW SCRF) electron linac. The 3.9 GHz third harmonic cavity similar to the XFEL design will be used in LCLS-II for linearizing the longitudinal beam profile*. The initial design of the 3.9 GHz cavity developed for XFEL project has a large, 40 mm, beam pipe aperture for better higher-order mode (HOM) damping. It is resulted in dipole HOMs with frequencies nearby the operating mode, which causes difficulties with HOM coupler notch filter tuning. The CW linac operationmore » requires an extra caution in the design of the HOM coupler in order to prevent its possible overheating. In this paper we present the modified 3.9 GHz cavity End Group for meeting the LCLS-II requirements« less

Standards for plant synthetic biology: a common syntax for exchange of DNA parts.

PubMed

Patron, Nicola J; Orzaez, Diego; Marillonnet, Sylvestre; Warzecha, Heribert; Matthewman, Colette; Youles, Mark; Raitskin, Oleg; Leveau, Aymeric; Farré, Gemma; Rogers, Christian; Smith, Alison; Hibberd, Julian; Webb, Alex A R; Locke, James; Schornack, Sebastian; Ajioka, Jim; Baulcombe, David C; Zipfel, Cyril; Kamoun, Sophien; Jones, Jonathan D G; Kuhn, Hannah; Robatzek, Silke; Van Esse, H Peter; Sanders, Dale; Oldroyd, Giles; Martin, Cathie; Field, Rob; O'Connor, Sarah; Fox, Samantha; Wulff, Brande; Miller, Ben; Breakspear, Andy; Radhakrishnan, Guru; Delaux, Pierre-Marc; Loqué, Dominique; Granell, Antonio; Tissier, Alain; Shih, Patrick; Brutnell, Thomas P; Quick, W Paul; Rischer, Heiko; Fraser, Paul D; Aharoni, Asaph; Raines, Christine; South, Paul F; Ané, Jean-Michel; Hamberger, Björn R; Langdale, Jane; Stougaard, Jens; Bouwmeester, Harro; Udvardi, Michael; Murray, James A H; Ntoukakis, Vardis; Schäfer, Patrick; Denby, Katherine; Edwards, Keith J; Osbourn, Anne; Haseloff, Jim

2015-10-01

Inventors in the field of mechanical and electronic engineering can access multitudes of components and, thanks to standardization, parts from different manufacturers can be used in combination with each other. The introduction of BioBrick standards for the assembly of characterized DNA sequences was a landmark in microbial engineering, shaping the field of synthetic biology. Here, we describe a standard for Type IIS restriction endonuclease-mediated assembly, defining a common syntax of 12 fusion sites to enable the facile assembly of eukaryotic transcriptional units. This standard has been developed and agreed by representatives and leaders of the international plant science and synthetic biology communities, including inventors, developers and adopters of Type IIS cloning methods. Our vision is of an extensive catalogue of standardized, characterized DNA parts that will accelerate plant bioengineering. © 2015 The Authors. New Phytologist © 2015 New Phytologist Trust.

Low-Energy Electron Interactions with CF_4

NASA Astrophysics Data System (ADS)

Christophorou, Loucas G.; Olthoff, James K.; Rao, M. V. V. S.

1996-10-01

Carbon tetrafluoride is one of the most widely used components of feed gas mixtures employed for a variety of plasma assisted materials processing applications. In this presentation, we synthesize and assess the available information on the cross sections and rate coefficients of collisional interations of CF4 with electrons.(L. G. Christophorou, J. K. Olthoff, and M.V. V. S. Rao, J. Phys. Chem. Ref. Data, submitted (May 1996)) A ``recommended'' data set is presented, based upon available data for: (i) cross sections for electron scattering (total, elastic, momentum, differential, inelastic), electron impact ionization (total and partial), electron impact dissociation, and electron attachment; and (ii) coefficients for electron transport, electron attachment, and electron impact ionization. -Research sponsored in part by the U.S. Air Force Wright Laboratory under contract F33615-96-C-2600 with the University of Tennessee. Also, Department of Physics, The University of Tennessee, Knoxville, TN.

Understanding Radiation Thermometry. Part II

NASA Technical Reports Server (NTRS)

Risch, Timothy K.

2015-01-01

This document is a two-part course on the theory and practice of radiation thermometry. Radiation thermometry is the technique for determining the temperature of a surface or a volume by measuring the electromagnetic radiation it emits. This course covers the theory and practice of radiative thermometry and emphasizes the modern application of the field using commercially available electronic detectors and optical components. The course covers the historical development of the field, the fundamental physics of radiative surfaces, along with modern measurement methods and equipment.

Single crystal EPR and optical studies of paramagnetic ions doped zinc potassium phosphate hexahydrate—Part I: Cu(II)—a case of orthorhombic symmetry

NASA Astrophysics Data System (ADS)

Sambasiva Rao, P.; Rajendiran, T. M.; Venkatesan, R.; Madhu, N.; Chandrasekhar, A. V.; Reddy, B. J.; Reddy, Y. P.; Ravikumar, R. V. S. S. N.

2001-12-01

Single crystal electron paramagnetic resonance (EPR) studies on Cu(II) doped zinc potassium phosphate hexahydrate (ZPPH) were carried out at room temperature. The angular variation spectra in the three orthogonal planes indicate that the paramagnetic impurity has entered the lattice substitutionally in place of Zn(II) and the spin Hamiltonian parameters calculated from these spectra are gxx=2.188, gyy=2.032, gzz=2.373, Axx=50 G, Ayy=65.0 G and Azz=80 G. The g and A tensors were coincident and these values matched fairly well with the values obtained from powder spectrum. The bonding parameters have also been calculated.

Chemical Science and Technology II. A Study Guide of the Science and Engineering Technician Curriculum.

ERIC Educational Resources Information Center

Ballinger, Jack T.; Wolf, Lawrence J.

This study guide is part of a program of studies entitled the Science and Engineering Technician (SET) Curriculum developed to provide a framework for training technicians in the use of electronic instruments and their applications. This interdisciplinary course of study integrates elements from the disciplines of chemistry, physics, mathematics,…

Electrical Experiments. VT-214-12-2. Part II. A-C Across the Line Control.

ERIC Educational Resources Information Center

Connecticut State Dept. of Education, Hartford. Div. of Vocational Education.

Designed for high school electronics students, this second document in a series of six electrical learning activity packages focuses on alternating current across-the-line control. An introductory section gives the objective for the activities, an introduction, and an outline of the content. The remainder of the activity book is comprised of…

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2010-10-01

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Electronic structure robustness and design rules for 2D colloidal heterostructures

NASA Astrophysics Data System (ADS)

Chu, Audrey; Livache, Clément; Ithurria, Sandrine; Lhuillier, Emmanuel

2018-01-01

Among the colloidal quantum dots, 2D nanoplatelets present exceptionally narrow optical features. Rationalizing the design of heterostructures of these objects is of utmost interest; however, very little work has been focused on the investigation of their electronic properties. This work is organized into two main parts. In the first part, we use 1D solving of the Schrödinger equation to extract the effective masses for nanoplatelets (NPLs) of CdSe, CdS, and CdTe and the valence band offset for NPL core/shell of CdSe/CdS. In the second part, using the determined parameters, we quantize how the spectra of the CdSe/CdS heterostructure get affected by (i) the application of an electric field and (ii) by the presence of a dull interface. We also propose design strategies to make the heterostructure even more robust.

Imaging Electron Spectrometer (IES) Electron Preprocessor (EPP) Design

NASA Technical Reports Server (NTRS)

Fennell, J. F.; Osborn, J. V.; Christensen, John L. (Technical Monitor)

2001-01-01

The Aerospace Corporation developed the Electron PreProcessor (EPP) to support the Imaging Electron Spectrometer (IES) that is part of the RAPID experiment on the ESA/NASA CLUSTER mission. The purpose of the EPP is to collect raw data from the IES and perform processing and data compression on it before transferring it to the RAPID microprocessor system for formatting and transmission to the CLUSTER satellite data system. The report provides a short history of the RAPID and CLUSTER programs and describes the EPP design. Four EPP units were fabricated, tested, and delivered for the original CLUSTER program. These were destroyed during a launch failure. Four more EPP units were delivered for the CLUSTER II program. These were successfully launched and are operating nominally on orbit.

Increased photosystem II stability promotes H2 production in sulfur-deprived Chlamydomonas reinhardtii

PubMed Central

Volgusheva, Alena; Styring, Stenbjörn; Mamedov, Fikret

2013-01-01

Photobiological H2 production is an attractive option for renewable solar fuels. Sulfur-deprived cells of Chlamydomonas reinhardtii have been shown to produce hydrogen with the highest efficiency among photobiological systems. We have investigated the photosynthetic reactions during sulfur deprivation and H2 production in the wild-type and state transition mutant 6 (Stm6) mutant of Chlamydomonas reinhardtii. The incubation period (130 h) was dissected into different phases, and changes in the amount and functional status of photosystem II (PSII) were investigated in vivo by electron paramagnetic resonance spectroscopy and variable fluorescence measurements. In the wild type it was found that the amount of PSII is decreased to 25% of the original level; the electron transport from PSII was completely blocked during the anaerobic phase preceding H2 formation. This block was released during the H2 production phase, indicating that the hydrogenase withdraws electrons from the plastoquinone pool. This partly removes the block in PSII electron transport, thereby permitting electron flow from water oxidation to hydrogenase. In the Stm6 mutant, which has higher respiration and H2 evolution than the wild type, PSII was analogously but much less affected. The addition of the PSII inhibitor 3-(3,4-dichlorophenyl)-1,1-dimethylurea revealed that ∼80% of the H2 production was inhibited in both strains. We conclude that (i) at least in the earlier stages, most of the electrons delivered to the hydrogenase originate from water oxidation by PSII, (ii) a faster onset of anaerobiosis preserves PSII from irreversible photoinhibition, and (iii) mutants with enhanced respiratory activity should be considered for better photobiological H2 production. PMID:23589846

Integrated Microphotonic Receiver for Ka-Band

NASA Technical Reports Server (NTRS)

Levi, A. F. J.

2005-01-01

This report consists of four main sections. Part I: LiNbO3 microdisk resonant optical modulator. Brief review of microdisk optical resonator and RF ring resonator. Microwave and photonic design challenges for achieving simultaneous RF-optical resonance are addressed followed by our solutions. Part II: Experimental demonstration of LiNbO3 microdisk modulator performance in wired and wireless RF-optical links. Part III: Microphotonic RF receiver architecture that exploits the nonlinear modulation in the LiNbO3 microdisk modulator to achieve direct photonic down-conversion from RF carrier without using any high-speed electronic elements. Part IV: Ultimate sensitivity of the microdisk photonic receiver and the future road map toward a practical device.

DESY II, a new injector for the DESY storage rings PETRA and DORIS II

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

Hemmie, G.

1983-08-01

There is a proposal to build a new 9 GeV electron synchrotron as a dedicated injector for the storage rings DORIS and PETRA. This machine will be housed in the old DESY-tunnel side-by-side with the original DESY-synchrotron. It is characterized by a separated function lattice, a 12.5 Hz repetition frequency, an all-metal vacuum chamber and a high shunt impedance rf-system. After commissioning of this new machine in 1984, the old DESY-synchrotron could be converted into a dedicated proton-accelerator as part of the injection chain for HERA.

Mutual interactions of redox couples via electron exchange in silicate melts - Models for geochemical melt systems

NASA Technical Reports Server (NTRS)

Schreiber, Henry D.; Merkel, Robert C., Jr.; Schreiber, V. Lea; Balazs, G. Bryan

1987-01-01

The mutual interactions via electron exchange of redox couples in glass-forming melts were investigated both theoretically and experimentally. A thermodynamic approach for considering the mutual interactions leads to conclusion that the degree of mutual interaction in the melt should be proportional in part to the difference in relative reduction potentials of the interacting redox couples. Experimental studies verify this conclusion for numerous redox couples in several composition/temperature/oxygen fugacity regimes. Geochemical systems simultaneously possess many potentially multivalent elements; the stabilized redox states in the resulting magmas can be explained in part by mutual interactions and by redox buffering through the central Fe(III)- Fe(II) couples in the melts. The significance of these results for basaltic magmas of the earth, moon, and meteorites is addressed.

Single crystal EPR and optical studies of paramagnetic ions doped zinc potassium phosphate hexahydrate--part I: Cu(II)--a case of orthorhombic symmetry.

PubMed

Sambasiva Rao, P; Rajendiran, T M; Venkatesan, R; Madhu, N; Chandrasekhar, A V; Reddy, B J; Reddy, Y P; Ravikumar, R V

2001-12-01

Single crystal electron paramagnetic resonance (EPR) studies on Cu(II) doped zinc potassium phosphate hexahydrate (ZPPH) were carried out at room temperature. The angular variation spectra in the three orthogonal planes indicate that the paramagnetic impurity has entered the lattice substitutionally in place of Zn(II) and the spin Hamiltonian parameters calculated from these spectra are g(xx) = 2.188, g(yy) = 2.032, g(zz) = 2.373, Axx = 50 G, Ayy = 65.0 G and Azz = 80 G. The g and A tensors were coincident and these values matched fairly well with the values obtained from powder spectrum. The bonding parameters have also been calculated.

BEETLE II: Deep Natural Language Understanding and Automatic Feedback Generation for Intelligent Tutoring in Basic Electricity and Electronics

ERIC Educational Resources Information Center

Dzikovska, Myroslava; Steinhauser, Natalie; Farrow, Elaine; Moore, Johanna; Campbell, Gwendolyn

2014-01-01

Within STEM domains, physics is considered to be one of the most difficult topics to master, in part because many of the underlying principles are counter-intuitive. Effective teaching methods rely on engaging the student in active experimentation and encouraging deep reasoning, often through the use of self-explanation. Supporting such…

78 FR 8509 - PPL Colstrip I, LLC, PPL Colstrip II, LLC, PPL Montana, LLC; Notice of Filing

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-06

... accounting and reporting requirements, except for sections 141.14 and 141.15. PPL Colstrip I requests such..., FERC Form No. 3-Q and meet other regulatory and accounting requirements imposed by these Parts from the... encourages electronic submission of protests and interventions in lieu of paper using the ``eFiling'' link at...

Noise propagation issues in Belle II pixel detector power cable

NASA Astrophysics Data System (ADS)

Iglesias, M.; Arteche, F.; Echeverria, I.; Pradas, A.; Rivetta, C.; Moser, H.-G.; Kiesling, C.; Rummel, S.; Arcega, F. J.

2018-04-01

The vertex detector used in the upgrade of High-Energy physics experiment Belle II includes DEPFET pixel detector (PXD) technology. In this complex topology the power supply units and the front-end electronics are connected through a PXD power cable bundle which may propagate the output noise from the power supplies to the vertex area. This paper presents a study of the propagation of noise caused by power converters in the PXD cable bundle based on Multi-conductor Transmission Line (MTL) theory. The work exposes the effect of the complex cable topology and shield connections on the noise propagation, which has an impact on the requirements of the power supplies. This analysis is part of the electromagnetic compatibility based design focused on functional safety to define the shield connections and power supply specifications required to ensure the successful integration of the detector and, specifically, to achieve the designed performance of the front-end electronics.

SPE-LEEM Studies on the Surface and Electronic Structure of 2-D Transition Metal Dichalcogenides (Part II)

NASA Astrophysics Data System (ADS)

Jin, Wencan; Yeh, Po-Chun; Zaki, Nader; Zhang, Datong; Sadowski, Jerzy; Al-Mahboob, Abdullah; van de Zande, Arend; Chenet, Daniel; Dadap, Jerry; Herman, Irving; Sutter, Peter; Hone, James; Osgood, Richard

2014-03-01

In this work, we studied the surface and electronic structure of monolayer and few-layer exfoliated MoS2 and WSe2, as well as chemical-vapor-deposition (CVD) grown MoS2, using Spectroscopic Photoemission and Low Energy Electron Microscope (SPE-LEEM). LEEM measurements reveal that, unlike exfoliated MoS2, CVD-grown MoS2 exhibits grain-boundary alterations due to surface strain. However, LEEM and micro-probe low energy electron diffraction show that the quality of CVD-grown MoS2 is comparable to that of exfoliated MoS2. Micrometer-scale angle-resolved photoemission spectroscopy (ARPES) measurement on exfoliated MoS2 and WSe2 single-crystals provides direct evidence for the shifting of the valence band maximum from Γ to K, when the layer number is thinned down to one, as predicted by density functional theory. Our measurements of the k-space resolved electronic structure allow for further comparison with other theoretical predictions and with transport measurements. This work is supported by DOE grant DE-FG 02-04-ER-46157, research carried out in part at the CFN and NSLS, Brookhaven National Laboratory.

Morphological evidence for local microcircuits in rat vestibular maculae

NASA Technical Reports Server (NTRS)

Ross, M. D.

1997-01-01

Previous studies suggested that intramacular, unmyelinated segments of vestibular afferent nerve fibers and their large afferent endings (calyces) on type I hair cells branch. Many of the branches (processes) contain vesicles and are presynaptic to type II hair cells, other processes, intramacular nerve fibers, and calyces. This study used serial section transmission electron microscopy and three-dimensional reconstruction methods to document the origins and distributions of presynaptic processes of afferents in the medial part of the adult rat utricular macula. The ultrastructural research focused on presynaptic processes whose origin and termination could be observed in a single micrograph. Results showed that calyces had 1) vesiculated, spine-like processes that invaginated type I cells and 2) other, elongate processes that ended on type II cells pre- as well as postsynaptically. Intramacular, unmyelinated segments of afferent nerve fibers gave origin to branches that were presynaptic to type II cells, calyces, calyceal processes, and other nerve fibers in the macula. Synapses with type II cells occurred opposite subsynaptic cisternae (C synapses); all other synapses were asymmetric. Vesicles were pleomorphic but were differentially distributed according to process origin. Small, clear-centered vesicles, approximately 40-60 nm in diameter, predominated in processes originating from afferent nerve fibers and basal parts of calyces. Larger vesicles approximately 70-120 nm in diameter having approximately 40-80 nm electron-opaque cores were dominant in processes originating from the necks of calyces. Results are interpreted to indicate the existence of a complex system of intrinsic feedforward (postsynaptic)-feedback (presynaptic) connections in a network of direct and local microcircuits. The morphological findings support the concept that maculae dynamically preprocess linear acceleratory information before its transmission to the central nervous system.

Double layers in expanding plasmas and their relevance to the auroral plasma processes

NASA Astrophysics Data System (ADS)

Singh, Nagendra; Khazanov, George

2003-04-01

When a dense plasma consisting of a cold and a sufficiently warm electron population expands, a rarefaction shock forms [, 1978]. In the expansion of the polar wind in the magnetosphere, it has been previously shown that when a sufficiently warm electron population also exists, in addition to the usual cold ionospheric one, a discontinuity forms in the electrostatic potential distribution along the magnetic field lines [, 1984]. Despite the lack of spatial resolution and the assumption of quasi-neutrality in the polar wind models, such discontinuities have been called double layers (DLs). Recently similar discontinuities have been invoked to partly explain the auroral acceleration of electrons and ions in the upward current region [, 2000]. By means of one-dimensional Vlasov simulations of expanding plasmas, for the first time we make here the connection between (1) the rarefaction shocks, (2) the discontinuities in the potential distributions, and (3) DLs. We show that when plasmas expand from opposite directions into a deep density cavity with a potential drop across it and when the plasma on the high-potential side contains hot and cold electron populations, the temporal evolution of the potential and the plasma distribution generates evolving multiple double layers with an extended density cavity between them. One of the DLs is the rarefaction-shock (RFS) and it forms by the reflections of the cold electrons coming from the high-potential side; it supports a part of the potential drop approximately determined by the hot electron temperature. The other DLs evolve from charge separations arising either from reflection of ions coming from the low-potential side or stemming from plasma instabilities; they support the rest of the potential drop. The instabilities forming these additional double layers involve electron-ion (e-i) Buneman or ion-ion (i-i) two-stream interactions. The electron-electron two-stream interactions on the high-potential side of the RFS generate electron-acoustic waves, which evolve into electron phase-space holes. The ion population originating from the low-potential side and trapped by the RFS is energized by the e-i and i-i instabilities and it eventually precipitates into the high-potential plasma along with an electron beam. Applications of these findings to the auroral plasma physics are discussed.

Double Layers in Expanding Plasmas and Their Relevance to the Auroral Plasma Processes

NASA Technical Reports Server (NTRS)

Singh, Nagendra; Khazanov, George

2003-01-01

When a dense plasma consisting of a cold and a sufficiently warm electron population expands, a rarefaction shock forms [Bezzerides et al., 1978]. In the expansion of the polar wind in the magnetosphere, it has been previously shown that when a sufficiently warm electron population also exists, in addition to the usual cold ionospheric one, a discontinuity forms in the electrostatic potential distribution along the magnetic field lines [Barakat and Schunk, 1984]. Despite the lack of spatial resolution and the assumption of quasi-neutrality in the polar wind models, such discontinuities have been called double layers (DLs). Recently similar discontinuities have been invoked to partly explain the auroral acceleration of electrons and ions in the upward current region [Ergun et al., 2000]. By means of one-dimensional Vlasov simulations of expanding plasmas, for the first time we make here the connection between (1) the rarefaction shocks, (2) the discontinuities in the potential distributions, and (3) DLs. We show that when plasmas expand from opposite directions into a deep density cavity with a potential drop across it and when the plasma on the high-potential side contains hot and cold electron populations, the temporal evolution of the potential and the plasma distribution generates evolving multiple double layers with an ,extended density cavity between them. One of the DLs is the rarefaction-shock (RFS) and it forms by the reflections of the cold electrons coming from the high-potential side; it supports a part of the potential drop approximately determined by the hot electron temperature. The other DLs evolve from charge separations arising either from reflection of ions coming from the low-potential side or stemming from plasma instabilities; they support the rest of the potential drop. The instabilities forming these additional double layers involve electron-ion (e-i) Buneman or ion-ion (i-i) two-stream interactions. The electron-electron two-stream interactions on the high-potential side of the RFS generate electron-acoustic waves, which evolve into electron phase-space holes. The ion population originating from the low-potential side and trapped by the RFS is energized by the e-i and i-i instabilities and it eventually precipitates into the high-potential plasma along with an electron beam. Applications of these findings to the auroral plasma physics are discussed.

Many-body and spin-orbit aspects of the alternating current phenomena

NASA Astrophysics Data System (ADS)

Glenn, Rachel M.

The thesis reports on research in the general field of light interaction with matter. According to the topics addressed, it can be naturally divided into two parts: Part I, many-body aspects of the Rabi oscillations which a two-level systems undergoes under a strong resonant drive; and Part II, absorption of the ac field between the spectrum branches of two-dimensional fermions that are split by the combined action of Zeeman and spin-orbit (SO) fields. The focus of Part I is the following many-body effects that modify the conventional Rabi oscillations: Chapter 1, coupling of a two-level system to a single vibrational mode of the environment. Chapter 2, correlated Rabi oscillations in two electron-hole systems coupled by tunneling with strong electron-hole attraction. In Chapter 1, a new effect of Rabi-vibronic resonance is uncovered. If the frequency of the Rabi oscillations, OR, is close to the frequency o0 of the vibrational mode, the oscillations acquire a collective character. It is demonstrated that the actual frequency of the collective oscillations exhibits a bistable behavior as a function of OR - o0. The main finding in Chapter 2 is, that the Fourier spectrum of the Rabi oscillations in two coupled electron-hole systems undergoes a strong transformation with increasing O R. For OR smaller than the tunneling frequency, the spectrum is dominated by a low-frequency (<< OR ) component and contains two additional weaker lines; conventional Rabi oscillations are restored only as OR exceeds the electron-hole attraction strength. The highlight of Part II is a finding that, while the spectrum of absorption between either Zeeman-split branches or SO-split branches is close to a delta-peak, in the presence of both, it transforms into a broad line with singular behavior at the edges. In particular, when the magnitudes of Zeeman and SO are equal, absorption of very low (much smaller than the splitting) frequencies become possible. The shape of the absorption spectrum is highly anisotropic with respect to the exciting field. This peculiar behavior of the absorption is also studied in wire geometry, where the interplay between two couplings (Zeeman and spin-orbit splitting) affects the shape of numerous absorption peaks.

Lots of data, how do we use it? Strengths and inaccuracies of utility acid rain electronic data reports

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

Schott, J.

1996-12-31

Entergy Corporation is a Phase II utility with a fossil generation base composed primarily natural gas and low sulfur coal. This paper presents an analysis of a large Phase II utility`s continuous emissions monitoring data reported to EPA under Title IV Acid Rain. Electric utilities currently report hourly emissions of NOx, SO{sub 2}, CO{sub 2}, fuel use, and generation through electronic data reports to EPA. This paper describes strengths and weaknesses of the data reported to EPA as determined through an analysis of 1995 data. Emissions reported by this company tinder acid rain for SO{sub 2} and NOx are verymore » different from emissions reported to state agencies for annual emission inventory purposes in past years and will represent a significant break with historic trends. A comparison of emissions has been made of 1995 emissions reported under Electronic Data Reports to the emissions that would have been reported using emission factors and fuel data in past years. In addition, the paper examines the impacts of 40 CFR Part 75 Acid Rain requirements such as missing data substitution and monitor bias adjustments. Measurement system errors including stack flow measurement and false NOx Lb/MMBtu readings at very low loads are discussed. This paper describes the implications for public policy, compliance, emissions inventories, and business decisions of Part 75 acid rain monitoring and reporting requirements.« less

Measurements of a Newly Designed BPM for the Tevatron Electron Lens 2

NASA Astrophysics Data System (ADS)

Scarpine, V. E.; Kamerdzhiev, V.; Fellenz, B.; Olson, M.; Kuznetsov, G.; Kamerdzhiev, V.; Shiltsev, V. D.; Zhang, X. L.

2006-11-01

Fermilab has developed a second electron lens (TEL-2) for beam-beam compensation in the Tevatron as part of its Run II upgrade program. Operation of the beam position monitors (BPMs) in the first electron lens (TEL-1) showed a systematic transverse position difference between short proton bunches (2 ns sigma) and long electron pulses (˜1 us) of up to ˜1.5 mm. This difference was attributed to frequency dependence in the BPM system. The TEL-2 BPMs utilize a new, compact four-plate design with grounding strips between plates to minimize crosstalk. In-situ measurements of these new BPMs are made using a stretched wire pulsed with both proton and electron beam formats. In addition, longitudinal impedance measurements of the TEL-2 are presented. Signal processing algorithm studies indicate that the frequency-dependent transverse position offset may be reduced to ˜0.1 mm for the beam structures of interest.

On The Stark Shift of Ar II 472.68 nm Spectral Line

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

Mijatovic, Z.; Gajo, T.; Vujicic, B.

The Stark shift of Ar II 472.68 nm (transition 4s2P - 4p2D deg. ) spectral lines emitted from T-tube plasmas was considered. The electron density ranged from (1.63-2.2){center_dot}1023 m-3 and was determined using laser interferometry. The plasma temperature, derived from the Gaussian part of recorded line profiles was found to be in the range (15000-43300) K. Experimental shifts were compared to theoretical values obtained from the semiempirical formula [M. S. Dimitrijevic and N. Konjevic, J. Quant. Spectrosc. Radiat. Transfer 24, 451 (1980)]. This comparison showed good agreement between experimental results and theory.

Low- and high-spin iron (II) complexes studied by effective crystal field method combined with molecular mechanics.

PubMed

Darkhovskii, M B; Pletnev, I V; Tchougréeff, A L

2003-11-15

A computational method targeted to Werner-type complexes is developed on the basis of quantum mechanical effective Hamiltonian crystal field (EHCF) methodology (previously proposed for describing electronic structure of transition metal complexes) combined with the Gillespie-Kepert version of molecular mechanics (MM). It is a special version of the hybrid quantum/MM approach. The MM part is responsible for representing the whole molecule, including ligand atoms and metal ion coordination sphere, but leaving out the effects of the d-shell. The quantum mechanical EHCF part is limited to the metal ion d-shell. The method reproduces with reasonable accuracy geometry and spin states of the Fe(II) complexes with monodentate and polydentate aromatic ligands with nitrogen donor atoms. In this setting a single set of MM parameters set is shown to be sufficient for handling all spin states of the complexes under consideration. Copyright 2003 Wiley Periodicals, Inc.

Trace Explosives Signatures from World War II Unexploded Undersea Ordnance

NASA Technical Reports Server (NTRS)

Darrach, M. R.; Chutjian, A.; Plett, G. A.

1998-01-01

Trace explosives signatures of TNT and DNT have been extracted from multiple sediment samples adjacent to unexploded undersea ordnance at Halifax Harbor, Canada. The ordnance was hurled into the harbor during a massive explosion some 50 years earlier, in 1945 after World War II had ended. Laboratory sediment extractions were made using the solid-phase microextraction (SPME) method in seawater and detection using the Reversal Electron Attachment Detection (READ) technique and, in the case of DNT, a commercial gas chromatograph/mass spectrometer (GC/MS). Results show that, after more than 50 years in the environment, ordnance that appeared to be physically intact gave good explosives signatures at the parts per billion level, whereas ordnance that had been cracked open during the explosion gave no signatures at the 10 parts per trillion sensitivity level. These measurements appear to provide the first reported data of explosives signatures from undersea unexploded ordnance.

The role of defects in Fe(II) – goethite electron transfer

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

Andrade de Notini, Luiza; Latta, Drew; Neumann, Anke

Despite accumulating experimental evidence for Fe(II)-Fe(III) oxide electron transfer, computational chemical calculations suggest that oxidation of sorbed Fe(II) is not energetically feasible unless defects are present. Here we used isotope specific 57Fe Mössbauer spectroscopy to investigate whether Fe(II)-goethite electron transfer is influenced by defects. Specifically, we heated the mineral to try to anneal the goethite surface and ground goethite to try to create defects. We found that heating goethite results in less oxidation of sorbed Fe(II) by goethite. When goethite was re-ground after heating, electron transfer was partially restored. X-ray absorption spectroscopy (XAS) and X-ray magnetic circular dichroism (XMCD) ofmore » heated and ground goethite confirm that heating and grinding alter the surface structure of the goethite. We propose that the heating process annealed the surface and decreased the number of sites where electron transfer could occur. Our experimental findings suggest that surface defects play an important role in Fe(II)-goethite electron transfer as suggested by computational calculations. Our finding that defects influence heterogeneous Fe(II)-goethite electron transfer has important implications for Fe(II) driven recrystallization of Fe oxides, as well as X and Y.« less

Revisiting the Supramolecular Organization of Photosystem II in Chlamydomonas reinhardtii*

PubMed Central

Tokutsu, Ryutaro; Kato, Nobuyasu; Bui, Khanh Huy; Ishikawa, Takashi; Minagawa, Jun

2012-01-01

Photosystem II (PSII) is a multiprotein complex that splits water and initiates electron transfer in photosynthesis. The central part of PSII, the PSII core, is surrounded by light-harvesting complex II proteins (LHCIIs). In higher plants, two or three LHCII trimers are seen on each side of the PSII core whereas only one is seen in the corresponding positions in Chlamydomonas reinhardtii, probably due to the absence of CP24, a minor monomeric LHCII. Here, we re-examined the supramolecular organization of the C. reinhardtii PSII-LHCII supercomplex by determining the effect of different solubilizing detergents. When we solubilized the thylakoid membranes with n-dodecyl-β-d-maltoside (β-DM) or n-dodecyl-α-d-maltoside (α-DM) and subjected them to gel filtration, we observed a clear difference in molecular mass. The α-DM-solubilized PSII-LHCII supercomplex bound twice more LHCII than the β-DM-solubilized supercomplex and retained higher oxygen-evolving activity. Single-particle image analysis from electron micrographs of the α-DM-solubilized and negatively stained supercomplex revealed that the PSII-LHCII supercomplex had a novel supramolecular organization, with three LHCII trimers attached to each side of the core. PMID:22801422

Synthesis and Analgesic Properties of Lidocaine Derivatives with Substituted Aminobenzothiazoles.

PubMed

Ahmadi, Abbas; Khalili, Mohsen; Mohammadinoude, Mohammad Kazem; Nahri-Niknafs, Babak

2016-01-01

Local anesthetics are the most widely consumed drugs in the practice of medicine which provide a loss of sensation in a certain body part without loss of consciousness or impairment of central control of essential functions. Lidocaine (I) is the most commonly local anaesthetic drug which is widely used in all species due to its fabulous diffusing and penetrating properties as well as prompt onset of surgical analgesia. In this study, new aminobenzothiazole (with many useful biological and pharmacological properties) analogues were synthesized by changing of amine moiety of I. Both acute and chronic pain properties of new compounds (II-VI) were studied by using the tail immersion and formalin tests on mice and the outcomes were compared with control and lidocaine groups. According to the results, aminobenzothiazole derivatives are better candidates than diethylamine group for replacement on amine moiety of I. Also, derivatives with electron-withdrawing groups on this amine (V and VI) could decrease pain better than electron-donating ones (II and III) (specially on position 6 of this amine, II and V) which may be of concern for blockade of specific sodium channels by these new compounds.

Thermoelectric effects in graphene at high bias current and under microwave irradiation.

PubMed

Skoblin, Grigory; Sun, Jie; Yurgens, August

2017-11-14

We use a split top gate to induce doping of opposite signs in different parts of a graphene field-effect transistor, thereby effectively forming a graphene thermocouple. The thermocouple is sensitive to the electronic temperature in graphene, which can be several hundred kelvin higher than the ambient one at sufficiently high bias current. Combined with the high thermoelectric power of graphene, this allows for i) simple measurements of the electronic temperature and ii) building thermoelectric radiation detectors. A simple prototype graphene thermoelectric detector shows a temperature-independent optical responsivity of around 400 V/W at 94 GHz at temperatures of 4-50 K.

Noise propagation issues in Belle II pixel detector power cable

DOE PAGES

Iglesias, M.; Arteche, F.; Echeverria, I.; ...

2018-04-26

The vertex detector used in the upgrade of High-Energy physics experiment Belle II includes DEPFET pixel detector (PXD) technology. In this complex topology the power supply units and the front-end electronics are connected through a PXD power cable bundle which may propagate the output noise from the power supplies to the vertex area. This article presents a study of the propagation of noise caused by power converters in the PXD cable bundle based on Multi-conductor Transmission Line (MTL) theory. The work exposes the effect of the complex cable topology and shield connections on the noise propagation, which has an impactmore » on the requirements of the power supplies. This analysis is part of the electromagnetic compatibility based design focused on functional safety to define the shield connections and power supply specifications required to ensure the successful integration of the detector and, specifically, to achieve the designed performance of the front-end electronics.« less

Noise propagation issues in Belle II pixel detector power cable

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

Iglesias, M.; Arteche, F.; Echeverria, I.

The vertex detector used in the upgrade of High-Energy physics experiment Belle II includes DEPFET pixel detector (PXD) technology. In this complex topology the power supply units and the front-end electronics are connected through a PXD power cable bundle which may propagate the output noise from the power supplies to the vertex area. This article presents a study of the propagation of noise caused by power converters in the PXD cable bundle based on Multi-conductor Transmission Line (MTL) theory. The work exposes the effect of the complex cable topology and shield connections on the noise propagation, which has an impactmore » on the requirements of the power supplies. This analysis is part of the electromagnetic compatibility based design focused on functional safety to define the shield connections and power supply specifications required to ensure the successful integration of the detector and, specifically, to achieve the designed performance of the front-end electronics.« less

The Coulomb based magneto-electric coupling in multiferroic tunnel junctions and granular multiferroics

NASA Astrophysics Data System (ADS)

Udalov, O. G.; Beloborodov, I. S.

2018-05-01

We study magneto-electric effect in two systems: i) multiferroic tunnel junction (MFTJ) - magnetic tunnel junction with ferroelectric barrier and ii) granular multiferroic (GMF) in which ferromagnetic (FM) metallic grains embedded into ferroelectric matrix. We show that the Coulomb interaction influences the magnetic state of the system in several ways: i) through the spin-dependent part of the Coulomb interaction; ii) due to the Coulomb blockade effect suppressing electron hopping and therefore reducing magnetic coupling; and iii) through image forces and polarization screening that modify the barrier for electrons in MFTJ and GMF. We show that in the absence of spin-orbit or strain-mediated coupling magneto-electric effect appears in GMF and MFTJ. The Coulomb interaction depends on the dielectric properties of the system. For GMF it depends on the dielectric constant of FE matrix and for MFTJ on the dielectric constant of the FE barrier. Applying external electric field one can tune the dielectric constant and the Coulomb interaction. Thus, one can control magnetic state with electric field.

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

Hogan, Mark

Plasma wakefield acceleration has the potential to dramatically shrink the size and cost of particle accelerators. Research at the SLAC National Accelerator Laboratory has demonstrated that plasmas can provide 1,000 times the acceleration in a given distance compared with current technologies. Developing revolutionary and more efficient acceleration techniques that allow for an affordable high-energy collider is the focus of FACET, a National User Facility at SLAC. The existing FACET National User Facility uses part of SLAC’s two-mile-long linear accelerator to generate high-density beams of electrons and positrons. FACET-II is a new test facility to develop advanced acceleration and coherent radiationmore » techniques with high-energy electron and positron beams. It is the only facility in the world with high energy positron beams. FACET-II provides a major upgrade over current FACET capabilities and the breadth of the potential research program makes it truly unique. It will synergistically pursue accelerator science that is vital to the future of both advanced acceleration techniques for High Energy Physics, ultra-high brightness beams for Basic Energy Science, and novel radiation sources for a wide variety of applications. The design parameters for FACET-II are set by the requirements of the plasma wakefield experimental program. To drive the plasma wakefield requires a high peak current, in excess of 10kA. To reach this peak current, the electron and positron design bunch size is 10μ by 10μ transversely with a bunch length of 10μ. This is more than 200 times better than what has been achieved at the existing FACET. The beam energy is 10 GeV, set by the Linac length available and the repetition rate is up to 30 Hz. The FACET-II project is scheduled to be constructed in three major stages. Components of the project discussed in detail include the following: electron injector, bunch compressors and linac, the positron system, the Sector 20 sailboat and W chicanes, and experimental area and infrastructure.« less

Actuator Characterization of Man Portable Precision Maneuver Concepts

DTIC Science & Technology

2014-03-01

brushless DC motors, along with a model of the rotating wing concept and a prototype 40-mm projectile, which was fired through the spark range (14), is... Brushless Electronic Speed Controller) was used to drive the three motor commutator input lines. This controller inputs a pulse-width modulated (PWM...Part II: The Brushless D.C. Motor Drive. IEEE Transactions on Industry Applications 1989, 25 (2), 274–279. 16. Hemati, N.; Leu, M. A Complete

Basic Studies on High Pressure Air Plasmas

DTIC Science & Technology

2006-08-30

which must be added a 1.5 month salary to A. Bugayev for assistance in laser and optic techniques. 2 Part II Technical report Plasma-induced phase shift...two-wavelength heterodyne interferometry applied to atmospheric pressure air plasma 11.1 .A. Plasma-induced phase shift - Electron density...a driver, since the error on the frequency leads to an error on the phase shift. (c) Optical elements Mirrors Protected mirrors must be used to stand

Combustion chemistry and flame structure of furan group biofuels using molecular-beam mass spectrometry and gas chromatography – Part III: 2,5-Dimethylfuran

PubMed Central

Togbé, Casimir; Tran, Luc-Sy; Liu, Dong; Felsmann, Daniel; Oßwald, Patrick; Glaude, Pierre-Alexandre; Sirjean, Baptiste; Fournet, René; Battin-Leclerc, Frédérique; Kohse-Höinghaus, Katharina

2013-01-01

This work is the third part of a study focusing on the combustion chemistry and flame structure of furan and selected alkylated derivatives, i.e. furan in Part I, 2-methylfuran (MF) in Part II, and 2,5-dimethylfuran (DMF) in the present work. Two premixed low-pressure (20 and 40 mbar) flat argon-diluted (50%) flames of DMF were studied with electron-ionization molecular-beam mass spectrometry (EI-MBMS) and gas chromatography (GC) under two equivalence ratios (φ=1.0 and 1.7). Mole fractions of reactants, products, and stable and radical intermediates were measured as a function of the distance to the burner. Kinetic modeling was performed using a reaction mechanism that was further developed in the present series, including Part I and Part II. A reasonable agreement between the present experimental results and the simulation is observed. The main reaction pathways of DMF consumption were derived from a reaction flow analysis. Also, a comparison of the key features for the three flames is presented, as well as a comparison between these flames of furanic compounds and those of other fuels. An a priori surprising ability of DMF to form soot precursors (e.g. 1,3-cyclopentadiene or benzene) compared to less substituted furans and to other fuels has been experimentally observed and is well explained in the model. PMID:24518851

Combustion chemistry and flame structure of furan group biofuels using molecular-beam mass spectrometry and gas chromatography - Part III: 2,5-Dimethylfuran.

PubMed

Togbé, Casimir; Tran, Luc-Sy; Liu, Dong; Felsmann, Daniel; Oßwald, Patrick; Glaude, Pierre-Alexandre; Sirjean, Baptiste; Fournet, René; Battin-Leclerc, Frédérique; Kohse-Höinghaus, Katharina

2014-03-01

This work is the third part of a study focusing on the combustion chemistry and flame structure of furan and selected alkylated derivatives, i.e. furan in Part I, 2-methylfuran (MF) in Part II, and 2,5-dimethylfuran (DMF) in the present work. Two premixed low-pressure (20 and 40 mbar) flat argon-diluted (50%) flames of DMF were studied with electron-ionization molecular-beam mass spectrometry (EI-MBMS) and gas chromatography (GC) under two equivalence ratios (φ=1.0 and 1.7). Mole fractions of reactants, products, and stable and radical intermediates were measured as a function of the distance to the burner. Kinetic modeling was performed using a reaction mechanism that was further developed in the present series, including Part I and Part II. A reasonable agreement between the present experimental results and the simulation is observed. The main reaction pathways of DMF consumption were derived from a reaction flow analysis. Also, a comparison of the key features for the three flames is presented, as well as a comparison between these flames of furanic compounds and those of other fuels. An a priori surprising ability of DMF to form soot precursors (e.g. 1,3-cyclopentadiene or benzene) compared to less substituted furans and to other fuels has been experimentally observed and is well explained in the model.

UV and X-ray Evolution of AR12230 as Observed with IRIS and FOXSI-II

NASA Astrophysics Data System (ADS)

Ryan, Daniel; Christe, Steven; Glesener, Lindsay; Vievering, Julie; Krucker, Sam; Ishikawa, Shin-Nosuke

2017-08-01

We present a multi-spectral and spatio-temporal analysis of AR12230 using both UV and X-ray spectroscopic imaging obtained as part of a coordinated observing campaign on 11 December 2014. The campaign involved IRIS (Interface Region Imaging Spectrometer) -- which provides both UV imaging and slit spectrograph observations of optically thick chromospheric and transition region emission -- and FOXSI-II (Focusing Optics X-ray Solar Imager) -- the second in a series of sounding rocket flights which combines grazing incidence direct focusing optics to produce solar X-ray spectroscopic imaging in the range 4-15keV. The active region exhibits a prolonged compact brightening in the IRIS 1330 A and 1400 A slit-jaw channels near the center of the active region throughout the duration of the observations. In the early phase of the observations FOXSI-II shows an X-ray source approximately 20x20 arcsec centered at the same location. The X-ray spectra show the presence of hot (~8 MK) thermal plasma and is suggestive of the presence of non-thermal electrons.. Later, two additional transient, spatially extended, simultaneous brightenings are observed, one of which was captured by the IRIS slit spectrograph. We combine these observations to explore the evolution and topology of the active region. Hydrodynamic modeling of the chromosphere is used to place a limit on the amount of non-thermal electrons required to produce the observed UV emission. This result is then compared to the limit inferred from the FOXSI-II X-ray spectra. Thus, we explore the role of non-thermal electrons and hydrodynamics in the energization and evolution of plasma in active regions.

Non-rigid alignment in electron tomography in materials science.

PubMed

Printemps, Tony; Bernier, Nicolas; Bleuet, Pierre; Mula, Guido; Hervé, Lionel

2016-09-01

Electron tomography is a key technique that enables the visualization of an object in three dimensions with a resolution of about a nanometre. High-quality 3D reconstruction is possible thanks to the latest compressed sensing algorithms and/or better alignment and preprocessing of the 2D projections. Rigid alignment of 2D projections is routine in electron tomography. However, it cannot correct misalignments induced by (i) deformations of the sample due to radiation damage or (ii) drifting of the sample during the acquisition of an image in scanning transmission electron microscope mode. In both cases, those misalignments can give rise to artefacts in the reconstruction. We propose a simple-to-implement non-rigid alignment technique to correct those artefacts. This technique is particularly suited for needle-shaped samples in materials science. It is initiated by a rigid alignment of the projections and it is then followed by several rigid alignments of different parts of the projections. Piecewise linear deformations are applied to each projection to force them to simultaneously satisfy the rigid alignments of the different parts. The efficiency of this technique is demonstrated on three samples, an intermetallic sample with deformation misalignments due to a high electron dose typical to spectroscopic electron tomography, a porous silicon sample with an extremely thin end particularly sensitive to electron beam and another porous silicon sample that was drifting during image acquisitions. © 2016 The Authors Journal of Microscopy © 2016 Royal Microscopical Society.

Mechanisms of electron transfer from structrual Fe(II) in reduced nontronite to oxygen for production of hydroxyl radicals

NASA Astrophysics Data System (ADS)

Yuan, Songhu; Liu, Xixiang; Liao, Wenjuan; Zhang, Peng; Wang, Xiaoming; Tong, Man

2018-02-01

Production of hydroxyl radicals (radOH) has been recently revealed upon oxygenation of sediments in redox-dynamic subsurface environments. In particular, Fe(II)-bearing clay minerals are the major sediment components contributing to radOH production upon oxygenation, and the produced radOH can oxidize contaminants and inactivate bacteria. Whereas, the mechanisms of radOH production from oxygenation of Fe(II)-bearing clay minerals remain elusive. The objectives of this study were to identify the structural variation of Fe(II) entities during the oxidation of Fe(II)-bearing clay minerals by O2, and to unravel the mechanisms of electron transfer within the mineral structure and from mineral to O2 for radOH production. Nontronite (NAu-2, 23% Fe) which was chemically reduced to 54.5% Fe(II) in total Fe was used as a model Fe(II)-bearing clay mineral. Production of radOH and oxidation of Fe(II) were measured during the oxidation of reduced NAu-2 by O2. A wide spectrum of spectroscopic techniques, including Fourier transform infrared spectroscopy (FTIR), Fe K-edge X-ray absorption spectroscopy (XAS), Mössbauer spectra, and X-ray photoelectron spectroscopy (XPS), were employed to explore the structural variation of Fe(II) entities in NAu-2 and the electron transfer within NAu-2 and from NAu-2 to O2. For 180 min oxidation of 1 g/L reduced NAu-2, a biphasic radOH production was observed, being quick within the initial 15 min and slow afterwards. Production of radOH correlates well with oxidation of Fe(II) in the reduced NAu-2. Within the initial 15 min, trioctahedral Fe(II)-Fe(II)-Fe(II) entities and edge Fe(II) in the reduced NAu-2 were preferentially and quickly oxidized, and electrons from the interior Fe(II)-Fe(II)-Fe(II) entities were most likely ejected from the basal siloxane plane to O2. Meanwhile, trioctahedral Fe(II)-Fe(II)-Fe(II) entities were mainly transformed to dioctahedral Fe(II)-Fe(II) entities. When the time of oxygenation was longer than 15 min, dioctahedral Al-Fe(II), Fe(II)-Fe(II) and Fe(II)-Fe(III) entities were slowly oxidized, and the interior electrons were transported through Fe(II)-O-Fe(III) linkages to edges and then ejected to O2. In the slow stage of oxidation, electrons from interior Fe(II) accumulated towards the near surface layers and fueled the regeneration of edge Fe(II) for radOH production. In both stages, one-electron transfer mechanism with the involvement of O2rad - and H2O2 applies for radOH production from the oxidation of structural Fe(II) by O2. The mechanisms unraveled in this study advance the understanding of reactive oxygen species (ROS) production and structural Fe variation when Fe(II)-bearing clay minerals are oxygenated in redox-dynamic systems.

Internal electron transfer between hemes and Cu(II) bound at cysteine beta93 promotes methemoglobin reduction by carbon monoxide.

PubMed

Bonaventura, C; Godette, G; Tesh, S; Holm, D E; Bonaventura, J; Crumbliss, A L; Pearce, L L; Peterson, J

1999-02-26

Previous studies showed that CO/H2O oxidation provides electrons to drive the reduction of oxidized hemoglobin (metHb). We report here that Cu(II) addition accelerates the rate of metHb beta chain reduction by CO by a factor of about 1000. A mechanism whereby electron transfer occurs via an internal pathway coupling CO/H2O oxidation to Fe(III) and Cu(II) reduction is suggested by the observation that the copper-induced rate enhancement is inhibited by blocking Cys-beta93 with N-ethylmaleimide. Furthermore, this internal electron-transfer pathway is more readily established at low Cu(II) concentrations in Hb Deer Lodge (beta2His --> Arg) and other species lacking His-beta2 than in Hb A0. This difference is consistent with preferential binding of Cu(II) in Hb A0 to a high affinity site involving His-beta2, which is ineffective in promoting electron exchange between Cu(II) and the beta heme iron. Effective electron transfer is thus affected by Hb type but is not governed by the R left arrow over right arrow T conformational equilibrium. The beta hemes in Cu(II)-metHb are reduced under CO at rates close to those observed for cytochrome c oxidase, where heme and copper are present together in the oxygen-binding site and where internal electron transfer also occurs.

Electromagnetic pulse (EMP), Part II: Field-expedient ways to minimize its effects on field medical treatment facilities.

PubMed

Vandre, R H; Klebers, J; Tesche, F M; Blanchard, J P

1993-05-01

Part I of this paper showed that a field commander can expect approximately 65% of his unprotected electronic medical equipment to be damaged by the electromagnetic pulse (EMP) from a single nuclear detonation as far as 2200 km away. Using computer modeling, field-expedient ways to minimize the effects of EMP were studied. The results were: (1) keep wiring near the ground, (2) keep wiring short, (3) unplug unused equipment, (4) run power cabling and tents in a magnetic north-south direction (avoid running power cabling in the east-west direction), and (5) place sensitive equipment in International Organization for Standardization shelters.

The museum maze in oral pathology demystifed: part II.

PubMed

Patil, Shankargouda; Rao, Roopa S; Ganavi, Bs

2013-09-01

Museum technology is perpetually changing due to current requirements and added inventions for our comfort and furbished display of specimens. Hence numerous methods of specimen preservation have been put on trial by diverse people in the medical feld as are the inventions. But only few have caught people's interest and are popularized today. This part provides unique insights into specialized custom-made techniques, evolution of recent advances like plastination and virtual museum that have popularized as visual delights. Plastination gives handy, perennial life-like acrylic specimens, whereas virtual museum takes museum feld to the electronic era making use of computers and virtual environment.

Highly planar diarylamine-fused porphyrins and their remarkably stable radical cations† †Electronic supplementary information (ESI) available. CCDC 1469154–1469160. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c6sc02721k Click here for additional data file. Click here for additional data file.

PubMed Central

Fukui, Norihito; Cha, Wonhee; Shimizu, Daiki; Oh, Juwon

2017-01-01

Oxidative fusion reactions of meso-phenoxazino Ni(ii) porphyrin were found to be temperature dependent, giving rise to either a doubly phenylene-fused product at room temperature or a singly phenoxazine-fused product at 70 °C. The latter was further oxidized to a doubly phenoxazine-fused Ni(ii) porphyrin, which was subsequently converted to the corresponding free base porphyrin and Zn(ii) porphyrin. Compared to previously reported diphenylamine-fused porphyrins that displayed a molecular twist, doubly phenoxazine-fused porphyrins exhibited distinctly different properties owing to their highly planar structures, such as larger fluorescence quantum yields, formation of an offset face-to-face dimer both in solution and the solid state, and the generation of a mixed-valence π-radical cation dimer upon electrochemical oxidation. One-electron oxidation of the phenoxazine-fused Ni(ii) porphyrin with Magic Blue gave the corresponding radical cation, which was certainly stable and could be isolated by separation over a silica gel column but slowly chlorinated at the reactive β-positions in the solid state. This finding led to us to examine β,β′-dichlorinated phenoxazine-fused and diphenylamine-fused Ni(ii) porphyrins, which, upon treatment with Magic Blue, provided remarkably stable radical cations to an unprecedented level. It is actually possible to purify these radical cations by silica gel chromatography, and they can be stored for over 6 months without any sign of deterioration. Moreover, they exhibited no degradation even after the CH2Cl2 solution was washed with water. However, subtle structural differences (planar versus partly twisted) led to different crystal packing structures and solid-state magnetic properties. PMID:28451165

Analysis of type II and type III solar radio bursts

NASA Astrophysics Data System (ADS)

Wijesekera, J. V.; Jayaratne, K. P. S. C.; Adassuriya, J.

2018-04-01

Solar radio burst is an arrangement of a frequency space that variation with time. Most of radio burst can be identified in low frequency range such as below 200 MHz and depending on frequencies. Solar radio bursts were the first phenomenon identified in the field of radio astronomy field. Solar radio frequency range is from 70 MHz to 2.2 GHz. Most of the radio burst can be identified in a low frequency range such as below 200 MHz. Properties of low-frequency radio were analyzed this research. There are two types of solar radio bursts were analyzed, named as type II and type III radio bursts. Exponential decay type could be seen in type II, and a linear could be indicated in type III solar radio bursts. The results of the drift rate graphs show the values of each chosen solar radio burst. High drift rate values can be seen in type III solar flares whereas low to medium drift rate values can be seen in type II solar flares. In the second part of the research the Newkirk model electron density model was used to estimate the drift velocities of the solar radio bursts. Although the special origin of the solar radio burst is not known clearly we assumed. The chosen solar radio bursts were originated within the solar radius of 0.9 - 1.3 range from the photosphere. We used power low in the form of (x) = A × 10‑bx were that the electron density related to the height of the solar atmosphere. The calculation of the plasma velocity of each solar radio burst was done using the electron density model and drift rates. Therefore velocity of chosen type II solar radio bursts indicates low velocities. The values are 233.2499 Km s‑1, 815.9522 Km s‑1 and 369.5425 Km s‑1. Velocity of chosen type III solar radio bursts were 1443.058 Km s‑1and 1205.05Km s ‑1.

Measurements of a Newly Designed BPM for the Tevatron Electron Lens 2

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

Scarpine, V. E.; Kamerdzhiev, V.; Fellenz, B.

2006-11-20

Fermilab has developed a second electron lens (TEL-2) for beam-beam compensation in the Tevatron as part of its Run II upgrade program. Operation of the beam position monitors (BPMs) in the first electron lens (TEL-1) showed a systematic transverse position difference between short proton bunches (2 ns sigma) and long electron pulses ({approx}1 us) of up to {approx}1.5 mm. This difference was attributed to frequency dependence in the BPM system. The TEL-2 BPMs utilize a new, compact four-plate design with grounding strips between plates to minimize crosstalk. In-situ measurements of these new BPMs are made using a stretched wire pulsedmore » with both proton and electron beam formats. In addition, longitudinal impedance measurements of the TEL-2 are presented. Signal processing algorithm studies indicate that the frequency-dependent transverse position offset may be reduced to {approx}0.1 mm for the beam structures of interest.« less

Simulation results of corkscrew motion in DARHT-II

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

Chan, K. D.; Ekdahl, C. A.; Chen, Y. J.

2003-01-01

DARHT-II, the second axis of the Dual-Axis Radiographic Hydrodynamics Test Facility, is being commissioned. DARHT-II is a linear induction accelerator producing 2-microsecond electron beam pulses at 20 MeV and 2 kA. These 2-microsecond pulses will be chopped into four short pulses to produce time resolved x-ray images. Radiographic application requires the DARHT-II beam to have excellent beam quality, and it is important to study various beam effects that may cause quality degradation of a DARHT-II beam. One of the beam dynamic effects under study is 'corkscrew' motion. For corkscrew motion, the beam centroid is deflected off axis due to misalignmentsmore » of the solenoid magnets. The deflection depends on the beam energy variation, which is expected to vary by {+-}0.5% during the 'flat-top' part of a beam pulse. Such chromatic aberration will result in broadening of beam spot size. In this paper, we will report simulation results of our study of corkscrew motion in DARHT-II. Sensitivities of beam spot size to various accelerator parameters and the strategy for minimizing corkscrew motion will be described. Measured magnet misalignment is used in the simulation.« less

Natural products from Pluchea sagittalis act as inhibitors of photosynthesis in vitro.

PubMed

Carvalho, Ana C; Lira, João C S; Pereira, Thaís M; Silva, Sebastião C; Simote-Silva, Simone Y; Oliveira, Fernando K D; King-Diaz, Beatriz; Lotina-Hennsen, Blas; Veiga, Thiago A M

2017-10-31

Four compounds were isolated from roots and aerial parts of Pluchea sagittalis (Asteraceae), 3, 5-dihydroxy-6, 7, 3', 4'-tetramethoxiflavunol (1), 5-hydroxymethylfurfural (2), 3, 4-dimethoxybenzaldehyde (3) and 2, 3, 4-trihydroxybenzaldeyde (4). Their herbicidal potential was detected by polarographic techniques. All of them inhibited the non-cyclic electron transport on basal, phosphorylating and uncoupled conditions from H 2 O to methylviologen (MV); thus, they act as Hill reaction inhibitors. Studies on fluorescence of chlorophyll a (ChL a) indicated they have different modes of interaction and inhibition sites on the photosystem II electron transport chain; 1-3 have interacted with the acceptor side while 4 has interacted at the donor side.

A new method for designing dual foil electron beam forming systems. II. Feasibility of practical implementation of the method

NASA Astrophysics Data System (ADS)

Adrich, Przemysław

2016-05-01

In Part I of this work a new method for designing dual foil electron beam forming systems was introduced. In this method, an optimal configuration of the dual foil system is found by means of a systematic, automatized scan of system performance in function of its parameters. At each point of the scan, Monte Carlo method is used to calculate the off-axis dose profile in water taking into account detailed and complete geometry of the system. The new method, while being computationally intensive, minimizes the involvement of the designer. In this Part II paper, feasibility of practical implementation of the new method is demonstrated. For this, a prototype software tools were developed and applied to solve a real life design problem. It is demonstrated that system optimization can be completed within few hours time using rather moderate computing resources. It is also demonstrated that, perhaps for the first time, the designer can gain deep insight into system behavior, such that the construction can be simultaneously optimized in respect to a number of functional characteristics besides the flatness of the off-axis dose profile. In the presented example, the system is optimized in respect to both, flatness of the off-axis dose profile and the beam transmission. A number of practical issues related to application of the new method as well as its possible extensions are discussed.

Electron transfer and atom exchange between aqueous Fe(II) and structural Fe(III) in clays. Role in U and Hg(II) transformations

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

Scherer, Michelle

2016-08-31

During this project, we investigated Fe electron transfer and atom exchange between aqueous Fe(II) and structural Fe(III) in clay minerals. We used selective chemical extractions, enriched Fe isotope tracer experiments, computational molecular modeling, and Mössbauer spectroscopy. Our findings indicate that structural Fe(III) in clay minerals is reduced by aqueous Fe(II) and that electron transfer occurs when Fe(II) is sorbed to either basal planes and edge OH-groups of clay mineral. Findings from highly enriched isotope experiments suggest that up to 30 % of the Fe atoms in the structure of some clay minerals exhanges with aqueous Fe(II). First principles calculations usingmore » a small polaron hopping approach suggest surprisingly fast electron mobility at room temperature in a nontronite clay mineral and are consistent with temperature dependent Mössbauer data Fast electron mobility suggests that electrons may be able to conduct through the mineral fast enough to enable exchange of Fe between the aqueous phase and clay mineral structure. over the time periods we observed. Our findings suggest that Fe in clay minerals is not as stable as previously thought.« less

Exact decoupling of the Dirac Hamiltonian. II. The generalized Douglas-Kroll-Hess transformation up to arbitrary order.

PubMed

Reiher, Markus; Wolf, Alexander

2004-12-08

In order to achieve exact decoupling of the Dirac Hamiltonian within a unitary transformation scheme, we have discussed in part I of this series that either a purely numerical iterative technique (the Barysz-Sadlej-Snijders method) or a stepwise analytic approach (the Douglas-Kroll-Hess method) are possible. For the evaluation of Douglas-Kroll-Hess Hamiltonians up to a pre-defined order it was shown that a symbolic scheme has to be employed. In this work, an algorithm for this analytic derivation of Douglas-Kroll-Hess Hamiltonians up to any arbitrary order in the external potential is presented. We discuss how an estimate for the necessary order for exact decoupling (within machine precision) for a given system can be determined from the convergence behavior of the Douglas-Kroll-Hess expansion prior to a quantum chemical calculation. Once this maximum order has been accomplished, the spectrum of the positive-energy part of the decoupled Hamiltonian, e.g., for electronic bound states, cannot be distinguished from the corresponding part of the spectrum of the Dirac operator. An efficient scalar-relativistic implementation of the symbolic operations for the evaluation of the positive-energy part of the block-diagonal Hamiltonian is presented, and its accuracy is tested for ground-state energies of one-electron ions over the whole periodic table. Furthermore, the first many-electron calculations employing sixth up to fourteenth order DKH Hamiltonians are presented. (c) 2004 American Institute of Physics.

Exact decoupling of the Dirac Hamiltonian. II. The generalized Douglas-Kroll-Hess transformation up to arbitrary order

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

Reiher, Markus; Wolf, Alexander

In order to achieve exact decoupling of the Dirac Hamiltonian within a unitary transformation scheme, we have discussed in part I of this series that either a purely numerical iterative technique (the Barysz-Sadlej-Snijders method) or a stepwise analytic approach (the Douglas-Kroll-Hess method) are possible. For the evaluation of Douglas-Kroll-Hess Hamiltonians up to a pre-defined order it was shown that a symbolic scheme has to be employed. In this work, an algorithm for this analytic derivation of Douglas-Kroll-Hess Hamiltonians up to any arbitrary order in the external potential is presented. We discuss how an estimate for the necessary order for exactmore » decoupling (within machine precision) for a given system can be determined from the convergence behavior of the Douglas-Kroll-Hess expansion prior to a quantum chemical calculation. Once this maximum order has been accomplished, the spectrum of the positive-energy part of the decoupled Hamiltonian, e.g., for electronic bound states, cannot be distinguished from the corresponding part of the spectrum of the Dirac operator. An efficient scalar-relativistic implementation of the symbolic operations for the evaluation of the positive-energy part of the block-diagonal Hamiltonian is presented, and its accuracy is tested for ground-state energies of one-electron ions over the whole periodic table. Furthermore, the first many-electron calculations employing sixth up to fourteenth order DKH Hamiltonians are presented.« less

Factors that control catalytic two- versus four-electron reduction of dioxygen by copper complexes.

PubMed

Fukuzumi, Shunichi; Tahsini, Laleh; Lee, Yong-Min; Ohkubo, Kei; Nam, Wonwoo; Karlin, Kenneth D

2012-04-25

The selective two-electron reduction of O(2) by one-electron reductants such as decamethylferrocene (Fc*) and octamethylferrocene (Me(8)Fc) is efficiently catalyzed by a binuclear Cu(II) complex [Cu(II)(2)(LO)(OH)](2+) (D1) {LO is a binucleating ligand with copper-bridging phenolate moiety} in the presence of trifluoroacetic acid (HOTF) in acetone. The protonation of the hydroxide group of [Cu(II)(2)(LO)(OH)](2+) with HOTF to produce [Cu(II)(2)(LO)(OTF)](2+) (D1-OTF) makes it possible for this to be reduced by 2 equiv of Fc* via a two-step electron-transfer sequence. Reactions of the fully reduced complex [Cu(I)(2)(LO)](+) (D3) with O(2) in the presence of HOTF led to the low-temperature detection of the absorption spectra due to the peroxo complex [Cu(II)(2)(LO)(OO)] (D) and the protonated hydroperoxo complex [Cu(II)(2)(LO)(OOH)](2+) (D4). No further Fc* reduction of D4 occurs, and it is instead further protonated by HOTF to yield H(2)O(2) accompanied by regeneration of [Cu(II)(2)(LO)(OTF)](2+) (D1-OTF), thus completing the catalytic cycle for the two-electron reduction of O(2) by Fc*. Kinetic studies on the formation of Fc*(+) under catalytic conditions as well as for separate examination of the electron transfer from Fc* to D1-OTF reveal there are two important reaction pathways operating. One is a rate-determining second reduction of D1-OTF, thus electron transfer from Fc* to a mixed-valent intermediate [Cu(II)Cu(I)(LO)](2+) (D2), which leads to [Cu(I)(2)(LO)](+) that is coupled with O(2) binding to produce [Cu(II)(2)(LO)(OO)](+) (D). The other involves direct reaction of O(2) with the mixed-valent compound D2 followed by rapid Fc* reduction of a putative superoxo-dicopper(II) species thus formed, producing D.

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

Strelnikov, N.; Vasserman, I.; Xu, J.

As part of the R&D program of the LCLS-II project, a novel 3.4-meter-long undulator prototype with horizontal magnetic field and dynamic force compensation has recently been developed at the Advanced Photon Source (APS). Some previous steps in this development were the shorter 0.8-meter-long and 2.8-meter-long prototypes. Extensive mechanical and magnetic testing was carried out for each prototype, and each prototype was magnetically tuned using magnetic shims. Furthermore, the resulting performance of the 3.4-meter-long undulator prototype meets all requirements for the LCLS-II insertion device, including limits on the field integrals, phase errors, higher-order magnetic moments, and electron-beam trajectory for all operationalmore » gaps, as well as the reproducibility and accuracy of the gap settings.« less

Parallel Large-scale Semidefinite Programming for Strong Electron Correlation: Using Correlation and Entanglement in the Design of Efficient Energy-Transfer Mechanisms

DTIC Science & Technology

2014-09-24

which nature uses strong electron correlation for efficient energy transfer, particularly in photosynthesis and bioluminescence, (ii) providing an...strong electron correlation for efficient energy transfer, particularly in photosynthesis and bioluminescence, (ii) providing an innovative paradigm...efficient energy transfer, particularly in photosynthesis and bioluminescence, (ii) providing an innovative paradigm for energy transfer in photovoltaic

Combustion chemistry and flame structure of furan group biofuels using molecular-beam mass spectrometry and gas chromatography – Part II: 2-Methylfuran

PubMed Central

Tran, Luc-Sy; Togbé, Casimir; Liu, Dong; Felsmann, Daniel; Oßwald, Patrick; Glaude, Pierre-Alexandre; Fournet, René; Sirjean, Baptiste; Battin-Leclerc, Frédérique; Kohse-Höinghaus, Katharina

2013-01-01

This is Part II of a series of three papers which jointly address the combustion chemistry of furan and its alkylated derivatives 2-methylfuran (MF) and 2,5-dimethylfuran (DMF) under premixed low-pressure flame conditions. Some of them are considered to be promising biofuels. With furan as a common basis studied in Part I of this series, the present paper addresses two laminar premixed low-pressure (20 and 40 mbar) flat argon-diluted (50%) flames of MF which were studied with electron-ionization molecular-beam mass spectrometry (EI-MBMS) and gas chromatography (GC) for equivalence ratios φ=1.0 and 1.7, identical conditions to those for the previously reported furan flames. Mole fractions of reactants, products as well as stable and reactive intermediates were measured as a function of the distance above the burner. Kinetic modeling was performed using a comprehensive reaction mechanism for all three fuels given in Part I and described in the three parts of this series. A comparison of the experimental results and the simulation shows reasonable agreement, as also seen for the furan flames in Part I before. This set of experiments is thus considered to be a valuable additional basis for the validation of the model. The main reaction pathways of MF consumption have been derived from reaction flow analyses, and differences to furan combustion chemistry under the same conditions are discussed. PMID:24518895

Combustion chemistry and flame structure of furan group biofuels using molecular-beam mass spectrometry and gas chromatography - Part II: 2-Methylfuran.

PubMed

Tran, Luc-Sy; Togbé, Casimir; Liu, Dong; Felsmann, Daniel; Oßwald, Patrick; Glaude, Pierre-Alexandre; Fournet, René; Sirjean, Baptiste; Battin-Leclerc, Frédérique; Kohse-Höinghaus, Katharina

2014-03-01

This is Part II of a series of three papers which jointly address the combustion chemistry of furan and its alkylated derivatives 2-methylfuran (MF) and 2,5-dimethylfuran (DMF) under premixed low-pressure flame conditions. Some of them are considered to be promising biofuels. With furan as a common basis studied in Part I of this series, the present paper addresses two laminar premixed low-pressure (20 and 40 mbar) flat argon-diluted (50%) flames of MF which were studied with electron-ionization molecular-beam mass spectrometry (EI-MBMS) and gas chromatography (GC) for equivalence ratios φ=1.0 and 1.7, identical conditions to those for the previously reported furan flames. Mole fractions of reactants, products as well as stable and reactive intermediates were measured as a function of the distance above the burner. Kinetic modeling was performed using a comprehensive reaction mechanism for all three fuels given in Part I and described in the three parts of this series. A comparison of the experimental results and the simulation shows reasonable agreement, as also seen for the furan flames in Part I before. This set of experiments is thus considered to be a valuable additional basis for the validation of the model. The main reaction pathways of MF consumption have been derived from reaction flow analyses, and differences to furan combustion chemistry under the same conditions are discussed.

ON THE NONTHERMAL κ-DISTRIBUTED ELECTRONS IN PLANETARY NEBULAE AND H ii REGIONS: THE κ INDEX AND ITS CORRELATIONS WITH OTHER NEBULAR PROPERTIES

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

Zhang, Yong; Zhang, Bing; Liu, Xiao-Wei, E-mail: zhangy96@hku.hk

2016-01-20

Recently, a suspicion arose that the free electrons in planetary nebulae (PNs) and H ii regions might have nonthermal energy distributions. In this scenario, a κ index is introduced to characterize the electron energy distributions, with smaller κ values indicating larger deviations from Maxwell–Boltzmann distributions. Assuming that this is the case, we determine the κ values for a sample of PNs and H ii regions by comparing the intensities of [O iii] collisionally excited lines and the hydrogen Balmer jump. We find the average κ indices of PNs and H ii regions to be 27 and 32, respectively. Correlations betweenmore » the resultant κ values and various physical properties of the nebulae are examined to explore the potential origin of nonthermal electrons in photoionized gaseous nebulae. However, no positive result is obtained. Thus, the current analysis does not lend support to the idea that κ-distributed electrons are present in PNs and H ii regions.« less

Proton-coupled electron-transfer reduction of dioxygen catalyzed by a saddle-distorted cobalt phthalocyanine.

PubMed

Honda, Tatsuhiko; Kojima, Takahiko; Fukuzumi, Shunichi

2012-03-07

Proton-coupled electron-transfer reduction of dioxygen (O(2)) to afford hydrogen peroxide (H(2)O(2)) was investigated by using ferrocene derivatives as reductants and saddle-distorted (α-octaphenylphthalocyaninato)cobalt(II) (Co(II)(Ph(8)Pc)) as a catalyst under acidic conditions. The selective two-electron reduction of O(2) by dimethylferrocene (Me(2)Fc) and decamethylferrocene (Me(10)Fc) occurs to yield H(2)O(2) and the corresponding ferrocenium ions (Me(2)Fc(+) and Me(10)Fc(+), respectively). Mechanisms of the catalytic reduction of O(2) are discussed on the basis of detailed kinetics studies on the overall catalytic reactions as well as on each redox reaction in the catalytic cycle. The active species to react with O(2) in the catalytic reaction is switched from Co(II)(Ph(8)Pc) to protonated Co(I)(Ph(8)PcH), depending on the reducing ability of ferrocene derivatives employed. The protonation of Co(II)(Ph(8)Pc) inhibits the direct reduction of O(2); however, the proton-coupled electron transfer from Me(10)Fc to Co(II)(Ph(8)Pc) and the protonated [Co(II)(Ph(8)PcH)](+) occurs to produce Co(I)(Ph(8)PcH) and [Co(I)(Ph(8)PcH(2))](+), respectively, which react immediately with O(2). The rate-determining step is a proton-coupled electron-transfer reduction of O(2) by Co(II)(Ph(8)Pc) in the Co(II)(Ph(8)Pc)-catalyzed cycle with Me(2)Fc, whereas it is changed to the electron-transfer reduction of [Co(II)(Ph(8)PcH)](+) by Me(10)Fc in the Co(I)(Ph(8)PcH)-catalyzed cycle with Me(10)Fc. A single crystal of monoprotonated [Co(III)(Ph(8)Pc)](+), [Co(III)Cl(2)(Ph(8)PcH)], produced by the proton-coupled electron-transfer reduction of O(2) by Co(II)(Ph(8)Pc) with HCl, was obtained, and the crystal structure was determined in comparison with that of Co(II)(Ph(8)Pc). © 2012 American Chemical Society

Processing of copper converter slag for metals reclamation: Part II: mineralogical study.

PubMed

Deng, Tong; Ling, Yunhan

2004-10-01

Chemical and mineralogical characterizations of a copper converter slag, and its products obtained by curing with strong sulphuric acid and leaching with hot water, were carried out using ore microscopy, scanning electronic microscopy with energy dispersive spectrometry, wave-length dispersive X-ray fluorescence spectrometry, X-ray diffractometry and chemical phase analysis, which provided necessary information to develop a new process for treating such slag and further understanding of the chemical and mineralogical changes in the process.

Thermomechanical Contact Phenomena and Wear of Sliding Components

DTIC Science & Technology

1989-07-31

seals. Many of those methods were used in this study. • • I I i II I I I I I I I l1 2. METHDS Sliding wear tests were conducted on Inconel 625 seal rings...wear. These coatings have been used successfully in reducing the wear of machine tools , aircraft and automobile engine parts, etc. It is only recently...scanning electron microscopy were tools employed to determine the wear behavior and wear mechanism associated with the various chromium carbide and tungsten

Coating Performance in Duluth Superior Harbor. Part 1

DTIC Science & Technology

2012-09-01

chemistry electron microscopy, and electrochemical techniques to in adsorption, bwfouling, hiodegrad ttoa, Mad corrosion in marine environments. She is a... Study off’nrrnmon Kxpowirc Testing h’tiUir Ä/jjjj Ijmm *7£ Compam Showcase CATHOOIC P 34 Onlhodte Pmieeiion of Sieel Pipe Pile* in an Open...of n Steel Drinking Water Pipe in an IIKIUOI l.u\\ ii-oiiinini /Juglins ll’iiiqi, .W lJu. Hnxin l’itng, ^kiuri IIV, amiHuijxiut dir» fcC

United States-Mexico electricity transfers: Of alien electrons and the migration of undocumented environmental burdens

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

Gandara, A.

This article intends to set forth the necessity for reform in the United States policy and procedures regarding approval of power transfers between the United States and Mexico. In order to do this, the article will review the history of electrical power transfers between the United States and Mexico (Part II), analyze recent regulatory changes in the United States and Mexico which may result in increased power exports to Mexico (Part III), evaluate the extent to which the present permit and authorization system in the United States considers the increased environmental burden of such power transfers (Part IV), and, wheremore » appropriate, propose some procedural and policy reforms that could take into account the environmental burdens generated by the production of power destined for transfer across the United States-Mexico border (Part V).« less

Type II flavohemoglobin of Mycobacterium smegmatis oxidizes d-lactate and mediate electron transfer.

PubMed

Thakur, Naveen; Kumar, Ashwani; Dikshit, Kanak L

2018-06-01

Two distantly related flavohemoglobins (FHbs), MsFHbI and MsFHbII, having crucial differences in their heme and reductase domains, co-exist in Mycobacterium smegmatis. Function of MsFHbI is associated with nitric-oxide detoxification but physiological relevance of MsFHbII remains unknown. This study unravels some unique spectral and functional characteristics of MsFHbII. Unlike conventional type I FHbs, MsFHbII lacks nitric-oxide dioxygenase and NADH oxidase activities but utilizes d-lactate as an electron donor to mediate electron transfer. MsFHbII carries a d-lactate dehydrogenase type FAD binding motif in its reductase domain and oxidizes d-lactate in a FAD dependent manner to reduce the heme iron, suggesting that the globin is acting as an electron acceptor. Importantly, expression of MsFHbII in Escherichia coli imparted protection under oxidative stress, suggesting its important role in stress management of its host. Since M. smegmatis lacks the gene encoding for d-lactate dehydrogenase and d-lactate is produced during aerobic metabolism and also as a by-product of lipid peroxidation, the ability of MsFHbII to metabolize d-lactate may provide it a unique ability to balance the oxidative stress generated due to accumulation of d-lactate in the cell and at the same time sequester electrons and pass it to the respiratory apparatus. Copyright © 2018 Elsevier B.V. All rights reserved.

[Algicidal effect of (2-isobutoxyphenyl) amine on Alexandrium tamarense].

PubMed

Zhang, Huajun; Peng, Yun; Zhang, Su; An, Xinli; Li, Yi; Zheng, Wei; Zheng, Tianling

2015-07-04

A strain named BS01 showed strong algicidal activity to Alexandrium tamarense and we got algicidal compound (2-isobutoxyphenyl) amine from BS01 to study its algicidal effect on A. tamarense. We studied the algicidal mechanism of (2-isobutoxyphenyl) amine on photosynthetic process, antioxidant enzyme activities and morphological change of A. tamarense. After 24 hours treatment with (2-isobutoxyphenyl) amine, algicidal activity was 84. 1% with the concentration of 20 µg/mL. The compound could induce a reactive oxygen species burst in P. globosa in 0. 5 hours which could cause serious oxidative damage to algal cells. The Fv/Fm value which could reflect photosystem II (PS II) electron flow status also decreased. To eliminate the excess ROS, the activities of the antioxidant systems (including superoxide dismutase and catalase) increased significantly during exposure. Transmission electron microscope analysis showed obvious morphological modifications of chloroplast dismantling as a part of the algicidal process. These results indicated that the lysis mechanism of algicidal compound on algae may primarily be the increasing level of ROS in the algal cells.

[Scanning electron microscopic observations of Monochamus alternatus antennal sensilla and their electroantennographic responses].

PubMed

Wang, Sibao; Zhou, Hongchun; Miao, Xuexia; Fan, Meizhen; Li, Zengzhi; Si, Shengli; Huang, Yongping

2005-02-01

With scanning electron microscope (SEM), this paper observed the shape, category, amount and distribution of the main antenna sensilla of adult Monochamus alternatus, and tested their electroantennographic (EAG) responses to the main volatiles of Pinus spp.. There were seven types of antennal sensilla, i. e., sensilla trichoid, sensilla basiconica, sensilla digit-like, sensilla rod-like, sensilla bottle-like, sensilla bud-like and sensilla chaetica, among which, sensilla trichoid and sensilla basiconica were the most abundant on the antenna surface, and each of them could be divided into three subtypes. Two subtypes of sensilla digit-like could also be observed. The II and III subtypes of sensilla trichoid and I and II subtypes of sensilla basiconica had deep longitudinal grooves on their surface, the typical characteristics of olfactory receptor. The comparison of the EAG response of different parts of Monochamus alternatus antennae to alpha-Pinene showed that each volatile and their compounds could provoke significant EAG responses of both females and males. The dose-response test showed that there was a certain rule in the EAG responses of M. alternatus.

Fluorescent probe based subcellular distribution of Cu(II) ions in living electrotrophs isolated from Cu(II)-reduced biocathodes of microbial fuel cells.

PubMed

Tao, Ye; Xue, Hua; Huang, Liping; Zhou, Peng; Yang, Wei; Quan, Xie; Yuan, Jinxiu

2017-02-01

Based on the four indigenous electrotrophs (Stenotrophomonas maltophilia JY1, Citrobacter sp. JY3, Pseudomonas aeruginosa JY5 and Stenotrophomonas sp. JY6) isolated from well adapted Cu(II)-reduced biocathodes of microbial fuel cells (MFCs), a rhodamine based Cu(II) fluorescent probe was used to imaginably and quantitatively track subcellular Cu(II) ions in these electrotrophs. Cathodic electrons led to more Cu(II) ions (14.3-30.1%) in the intracellular sites at operation time of 2-3h with Cu(II) removal rates of 2.90-3.64mg/Lh whereas the absence of cathodic electrons prolonged the appearance of more Cu(II) ions (16.6-22.5%) to 5h with Cu(II) removal rates of 1.96-2.28mg/Lh. This study illustrates that cathodic electrons directed more Cu(II) ions for quicker entrance into the electrotrophic cytoplasm, and gives an alternative approach for developing imaging and functionally tracking Cu(II) ions in the electrotrophs of MFCs. Copyright © 2016 Elsevier Ltd. All rights reserved.

40 CFR 52.2465 - Original identification of plan section.

Code of Federal Regulations, 2010 CFR

2010-07-01

..., 2FSD, and pre-dryer 3FSD from Part IV, Rule EX-4, Section 4.41(i) until December 15, 1981, submitted on...) Appendix K (7) Appendix N (8) Appendix P (9) Appendix R I., II.B., II.D., II.E., II.F., II.G., II.H., II.I...) Amendments to Part I, Subpart 1.01 (Certain Terms Defined) and to Part IV, Section 4.52 (former Section 4.705...

5-Arylvinyl-2,2′-bipyridyls: Bright “push–pull” dyes as components in fluorescent indicators for zinc ions

PubMed Central

Zhu, Lei; Younes, Ali H.; Yuan, Zhao; Clark, Ronald J.

2015-01-01

This article reviews the zinc(II)-dependent photophysical properties of arylvinylbipyridines (AVBs), a class of fluoroionophores in which 2,2′-bipyridyl and an aryl moiety are electronically conjugated. Zinc(II) binding of an AVB may lead to an emission bathochromic shift of the fluoroionophore without diminishing its fluorescence quantum yield. This observation can be explained using the excited state model of electron donor–π bridge–electron acceptor “push–pull” fluorophores, in which the bipy moiety acts as an electron acceptor, and zinc(II)-coordination strengthens its electron affinity. The spectral sensitivity of bipy-containing fluoroionophores, such as AVBs, to zinc(II) can be exploited to prepare fluorescent indicators for this ion. In several cases, AVB moieties are incorporated in fluorescent heteroditopic ligands, so that the variation of zinc(II) concentration over a relatively large range can be correlated to fluorescence changes in either intensity or color. AVB fluoroionophores are also used to introduce an intramolecular Förster resonance energy transfer (FRET) strategy for creating zinc(II) indicators with high photostability and a narrow emission band, two desired characteristics of dyes used in fluorescence microscopy. PMID:26190906

Central Drift Chamber for Belle-II

NASA Astrophysics Data System (ADS)

Taniguchi, N.

2017-06-01

The Central Drift Chamber (CDC) is the main device for tracking and identification of charged particles for Belle-II experiment. The Belle-II CDC is cylindrical wire chamber with 14336 sense wires, 2.3 m-length and 2.2 m-diameter. The wire chamber and readout electronics have been completely replaced from the Belle CDC. The new readout electronics system must handle higher trigger rate of 30 kHz with less dead time at the design luminosity of 8 × 1035 cm-2s-1. The front-end electronics are located close to detector and send digitized signal through optical fibers. The Amp-Shaper-Discriminator chips, FADC and FPGA are assembled on a single board. Belle-II CDC with readout electronics has been installed successfully in Belle structure in October 2016. We will present overview of the Belle-II CDC and status of commissioning with cosmic ray.

Na8Au9.8(4)Ga7.2 and Na17Au5.87(2)Ga46.63: The diversity of pseudo 5-fold symmetries in the Na-Au-Ga system

NASA Astrophysics Data System (ADS)

Smetana, Volodymyr; Corbett, John D.; Miller, Gordon J.

2013-11-01

The Na-rich part (~30% Na) of the Na-Au-Ga system between NaAu2, NaGa4, and Na22Ga39 has been found to contain the ternary phases Na8Au9.8(4)Ga7.2 (I) and Na17Au5.87(2)Ga46.63 (II), according to the results of single crystal X-ray diffraction measurements. I is orthorhombic, Cmcm, a=5.3040(1), b=24.519(5), c=14.573(3) Å, and contains a network of clusters with local 5-fold symmetry along the a-axis. Such clusters are frequent building units in decagonal quasicrystals and their approximants. II is rhombohedral, R3¯m, a=16.325(2), c=35.242(7) Å, and contains building blocks that are structurally identical to the Bergman-type clusters as well as fused icosahedral units known with active metals, triels and late transition elements. II also contains a polycationic network with elements of the clathrate V type structure. Tight-binding electronic structure calculations using linear muffin-tin-orbital (LMTO) methods on idealized models of I and II indicate that both compounds are metallic with evident pseudogaps at the corresponding Fermi levels. The overall Hamilton bond populations are generally dominated by Au-Ga and Au-Au bonds in I and by Ga-Ga bonds in II; moreover, the Na-Au and Na-Ga contributions in I are unexpectedly large, ~20% of the total. A similar involvement of sodium in covalent bonding has also been found in the electron-richer i-Na13Au12Ga15 quasicrystal approximant.

Pulsed plasma chemical synthesis of SixCyOz composite nanopowder

NASA Astrophysics Data System (ADS)

Kholodnaya, G.; Sazonov, R.; Ponomarev, D.; Remnev, G.

2017-05-01

SixCyOz composite nanopowder with an average size of particles about 10-50 nm was produced using the pulsed plasma chemical method. The experiments on the synthesis of nanosized composite were carried out using a TEA-500 pulsed electron accelerator. To produce a composite, SiCl4, O2, and CH4 were used. The major part of experiments was conducted using a plasma chemical reactor (quartz, 140 mm diameter, 6 l volume). The initial reagents were injected into the reactor, then a pulsed electron beam was injected which initiated the chemical reactions whose products were the SixCyOz composite nanopowder. To define the morphology of the particles, the JEOL-II-100 transmission electron microscope (TEM) with an accelerating voltage of 100 kV was used. The substances in the composition of the composite nanopowder were identified using the infrared absorption optical spectrum. To conduct this analysis, the Nicolet 5700 FT-IR spectrometer was used.

Ionic-to-Electronic Conductivity Crossover in CdTe-AgI-As2Te3 Glasses: An 110mAg Tracer Diffusion Study.

PubMed

Kassem, M; Alekseev, I; Bokova, M; Le Coq, D; Bychkov, E

2018-04-12

Conductivity isotherms of (CdTe) x (AgI) 0.5- x/2 (As 2 Te 3 ) 0.5- x/2 glasses (0.0 ≤ x ≤ 0.15) reveal a nonmonotonic behavior with increasing CdTe content reminiscent of mixed cation effect in oxide and chalcogenide glasses. Nevertheless, the apparent similarity appears to be partly incorrect. Using 110m Ag tracer diffusion measurements, we show that semiconducting CdTe additions produce a dual effect: (i) decreasing the Ag + ion transport by a factor of ≈200 with a simultaneous increase of the diffusion activation energy and (ii) increasing the electronic conductivity by 1.5 orders of magnitude. Consequently, the conductivity minimum at x = 0.05 reflects an ionic-to-electronic transport crossover; the silver-ion transport number decreases by 3 orders of magnitude with increasing x.

Hydrolytic catalysis and structural stabilization in a designed metalloprotein

PubMed Central

Zastrow, Melissa L.; Peacock, Anna F. A.; Stuckey, Jeanne A.; Pecoraro, Vincent L.

2011-01-01

Metal ions are an important part of many natural proteins, providing structural, catalytic and electron transfer functions. Reproducing these functions in a designed protein is the ultimate challenge to our understanding of them. Here, we present an artificial metallohydrolase, which has been shown by X-ray crystallography to contain two different metal ions – a Zn(II) ion which is important for catalytic activity and a Hg(II) ion which provides structural stability. This metallohydrolase displays catalytic activity that compares well with several characteristic reactions of natural enzymes. It catalyses p-nitrophenyl acetate hydrolysis (pNPA) to within ~100-fold of the efficiency of human carbonic anhydrase (CA)II and is at least 550-fold better than comparable synthetic complexes. Similarly, CO2 hydration occurs with an efficiency within ~500-fold of CAII. While histidine residues in the absence of Zn(II) exhibit pNPA hydrolysis, miniscule apopeptide activity is observed for CO2 hydration. The kinetic and structural analysis of this first de novo designed hydrolytic metalloenzyme uncovers necessary design features for future metalloenzymes containing one or more metals. PMID:22270627

19 CFR Annex II to Part 351 - Deadlines for Parties in Countervailing Administrative Reviews

Code of Federal Regulations, 2010 CFR

2010-04-01

... 19 Customs Duties 3 2010-04-01 2010-04-01 false Deadlines for Parties in Countervailing Administrative Reviews II Annex II to Part 351 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE ANTIDUMPING AND COUNTERVAILING DUTIES Pt. 351, Annex II Annex II to Part 351—Deadlines for Parties...

19 CFR Annex II to Part 351 - Deadlines for Parties in Countervailing Administrative Reviews

Code of Federal Regulations, 2011 CFR

2011-04-01

... 19 Customs Duties 3 2011-04-01 2011-04-01 false Deadlines for Parties in Countervailing Administrative Reviews II Annex II to Part 351 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE ANTIDUMPING AND COUNTERVAILING DUTIES Pt. 351, Annex II Annex II to Part 351—Deadlines for Parties...

19 CFR Annex II to Part 351 - Deadlines for Parties in Countervailing Administrative Reviews

Code of Federal Regulations, 2014 CFR

2014-04-01

... 19 Customs Duties 3 2014-04-01 2014-04-01 false Deadlines for Parties in Countervailing Administrative Reviews II Annex II to Part 351 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE ANTIDUMPING AND COUNTERVAILING DUTIES Pt. 351, Annex II Annex II to Part 351—Deadlines for Parties...

19 CFR Annex II to Part 351 - Deadlines for Parties in Countervailing Administrative Reviews

Code of Federal Regulations, 2013 CFR

2013-04-01

... 19 Customs Duties 3 2013-04-01 2013-04-01 false Deadlines for Parties in Countervailing Administrative Reviews II Annex II to Part 351 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE ANTIDUMPING AND COUNTERVAILING DUTIES Pt. 351, Annex II Annex II to Part 351—Deadlines for Parties...

19 CFR Annex II to Part 351 - Deadlines for Parties in Countervailing Administrative Reviews

Code of Federal Regulations, 2012 CFR

2012-04-01

... 19 Customs Duties 3 2012-04-01 2012-04-01 false Deadlines for Parties in Countervailing Administrative Reviews II Annex II to Part 351 Customs Duties INTERNATIONAL TRADE ADMINISTRATION, DEPARTMENT OF COMMERCE ANTIDUMPING AND COUNTERVAILING DUTIES Pt. 351, Annex II Annex II to Part 351—Deadlines for Parties...

10 CFR Appendix II to Part 504 - Fuel Price Computation

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 4 2012-01-01 2012-01-01 false Fuel Price Computation II Appendix II to Part 504 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS EXISTING POWERPLANTS Pt. 504, App. II Appendix II to Part 504—Fuel Price Computation (a) Introduction. This appendix provides the equations and parameters...

40 CFR Appendix II to Part 1048 - Large Spark-ignition (SI) Composite Transient Cycle

Code of Federal Regulations, 2010 CFR

2010-07-01

... Transient Cycle II Appendix II to Part 1048 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY.... 1048, App. II Appendix II to Part 1048—Large Spark-ignition (SI) Composite Transient Cycle The following table shows the transient duty-cycle for engines that are not constant-speed engines, as described...

Paramagnetic resonance studies of bistrispyrazolylborate cobalt(II) and related derivatives

NASA Astrophysics Data System (ADS)

Myers, William K.

Herein, a systematic frozen solution electron-nuclear double resonance (ENDOR) study of high-spin Co(II) complexes is reported to demonstrate the efficacy of methyl substitutions as a means of separating dipolar and contact coupling, and further, to increase the utility of high-spin Co(II) as a spectroscopic probe for the ubiquitous, but spectroscopically-silent Zn(II) metalloenzymes. High-spin (hs) Co(II) has been subject of paramagnetic resonance studies for over 50 years and has been used as a spectroscopic probe for Zn metalloenzymes for over 35 years. However, as will be seen, the inherent complexity of the electronic properties of the cobaltous ion remains to be exploited to offer a wealth of information on Zn(II) enzymatic environments. Specifically, ENDOR measurements on bistrispyrazolylborate cobalt(II) confirm the utility of the novel method of methyl substitution to differentiate dipolar and Fermi contact couplings. An extensive set of electron paramagnetic resonance (EPR) simulations were performed. Software was developed to implement an ENDOR control interface. Finally, proton relaxation measurements were made in the range of 12-42 MHz, which were accounted for with the large g-value anisotropy of the Co(II) compounds. Taken as a whole, these studies point to the rich complexity of the electronic structure of high-spin cobalt(II) and, when sufficiently well-characterized, the great utility it has as a surrogate of biological Zn(II).

Influence of central metalloligand geometry on electronic communication between metals: syntheses, crystal structures, MMCT properties of isomeric cyanido-bridged Fe2Ru complexes, and TDDFT calculations.

PubMed

Ma, Xiao; Lin, Chen-Sheng; Hu, Sheng-Min; Tan, Chun-Hong; Wen, Yue-Hong; Sheng, Tian-Lu; Wu, Xin-Tao

2014-06-02

To investigate how the central metalloligand geometry influences distant or vicinal metal-to-metal charge-transfer (MMCT) properties of polynuclear complexes, cis- and trans-isomeric heterotrimetallic complexes, and their one- and two-electron oxidation products, cis/trans-[Cp(dppe)Fe(II)NCRu(II)(phen)2CN-Fe(II)(dppe)Cp][PF6]2 (cis/trans-1[PF6]2), cis/trans-[Cp(dppe)Fe(II)NCRu(II)(phen)2CNFe(III)-(dppe)Cp][PF6]3 (cis/trans-1[PF6]3) and cis/trans-[Cp(dppe)Fe(III)NCRu(II)(phen)2CN-Fe(III)(dppe)Cp][PF6]4 (cis/trans-1[PF6]4) have been synthesized and characterized. Electrochemical measurements show the presence of electronic interactions between the two external Fe(II) atoms of the cis- and trans-isomeric complexes cis/trans-1[PF6]2. The electronic properties of all these complexes were studied and compared by spectroscopic techniques and TDDFT//DFT calculations. As expected, both mixed valence complexes cis/trans-1[PF6]3 exhibited different strong absorption signals in the NIR region, which should mainly be attributed to a transition from an MO that is delocalized over the Ru(II)-CN-Fe(II) subunit to a Fe(III) d orbital with some contributions from the co-ligands. Moreover, the NIR transition energy in trans-1[PF6]3 is lower than that in cis-1[PF6]3, which is related to the symmetry of their molecular orbitals on the basis of the molecular orbital analysis. Also, the electronic spectra of the two-electron oxidized complexes show that trans-1[PF6]4 possesses lower vicinal Ru(II) → Fe(III) MMCT transition energy than cis-1[PF6]4. Moreover, the assignment of MMCT transition of the oxidized products and the differences of the electronic properties between the cis and trans complexes can be well rationalized using TDDFT//DFT calculations. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

40 CFR Appendix II to Part 261 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 25 2010-07-01 2010-07-01 false [Reserved] II Appendix II to Part 261 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) IDENTIFICATION AND LISTING OF HAZARDOUS WASTE Appendix II to Part 261 [Reserved] ...

Understanding plume splitting of laser ablated plasma: A view from ion distribution dynamics

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

Wu, Jian; Li, Xingwen; Wei, Wenfu

2013-11-15

Plume splitting in low-pressure ambient air was understood in view of ion distribution dynamics from the laser ablated Al plasma (1064 nm 0.57 J/mm{sup 2}) by combining fast photography and spatially resolved spectroscopy. In the beginning, the spectral lines were mainly from the Al III ion. Then, the Bragg peak in stopping power of the ambient gas to Al III could be the dominant reason for the enhanced emission from the fast moving part, and the recombination of Al III to Al I-II ions near the target surface was response to the radiations from the slow moving/stationary part. As themore » ambient gas pressure increased, stopping distances of the Al III decreased, and radiation from the air ions became pronounced. The laser shadowgraph image at 1100 Pa indicated that the shock wave front located between the fast moving and slow moving parts. Electron densities of the fast moving plasma, which peaked at the plasma front, were on the order of 10{sup 16} cm{sup −3}, and the electron temperatures were 2–3 eV.« less

Quantum Field Theory Approach to Condensed Matter Physics

NASA Astrophysics Data System (ADS)

Marino, Eduardo C.

2017-09-01

Preface; Part I. Condensed Matter Physics: 1. Independent electrons and static crystals; 2. Vibrating crystals; 3. Interacting electrons; 4. Interactions in action; Part II. Quantum Field Theory: 5. Functional formulation of quantum field theory; 6. Quantum fields in action; 7. Symmetries: explicit or secret; 8. Classical topological excitations; 9. Quantum topological excitations; 10. Duality, bosonization and generalized statistics; 11. Statistical transmutation; 12. Pseudo quantum electrodynamics; Part III. Quantum Field Theory Approach to Condensed Matter Systems: 13. Quantum field theory methods in condensed matter; 14. Metals, Fermi liquids, Mott and Anderson insulators; 15. The dynamics of polarons; 16. Polyacetylene; 17. The Kondo effect; 18. Quantum magnets in 1D: Fermionization, bosonization, Coulomb gases and 'all that'; 19. Quantum magnets in 2D: nonlinear sigma model, CP1 and 'all that'; 20. The spin-fermion system: a quantum field theory approach; 21. The spin glass; 22. Quantum field theory approach to superfluidity; 23. Quantum field theory approach to superconductivity; 24. The cuprate high-temperature superconductors; 25. The pnictides: iron based superconductors; 26. The quantum Hall effect; 27. Graphene; 28. Silicene and transition metal dichalcogenides; 29. Topological insulators; 30. Non-abelian statistics and quantum computation; References; Index.

THE POSSIBLE ROLE OF CORONAL STREAMERS AS MAGNETICALLY CLOSED STRUCTURES IN SHOCK-INDUCED ENERGETIC ELECTRONS AND METRIC TYPE II RADIO BURSTS

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

Kong, Xiangliang; Chen, Yao; Feng, Shiwei

2015-01-10

Two solar type II radio bursts, separated by ∼24 hr in time, are examined together. Both events are associated with coronal mass ejections (CMEs) erupting from the same active region (NOAA 11176) beneath a well-observed helmet streamer. We find that the type II emissions in both events ended once the CME/shock fronts passed the white-light streamer tip, which is presumably the magnetic cusp of the streamer. This leads us to conjecture that the closed magnetic arcades of the streamer may play a role in electron acceleration and type II excitation at coronal shocks. To examine such a conjecture, we conduct a test-particle simulationmore » for electron dynamics within a large-scale partially closed streamer magnetic configuration swept by a coronal shock. We find that the closed field lines play the role of an electron trap via which the electrons are sent back to the shock front multiple times and therefore accelerated to high energies by the shock. Electrons with an initial energy of 300 eV can be accelerated to tens of keV concentrating at the loop apex close to the shock front with a counter-streaming distribution at most locations. These electrons are energetic enough to excite Langmuir waves and radio bursts. Considering the fact that most solar eruptions originate from closed field regions, we suggest that the scenario may be important for the generation of more metric type IIs. This study also provides an explanation of the general ending frequencies of metric type IIs at or above 20-30 MHz and the disconnection issue between metric and interplanetary type IIs.« less

Isolation of a matrix that binds medial Golgi enzymes

PubMed Central

1994-01-01

Rat liver Golgi stacks were extracted with Triton X-100 at neutral pH. After centrifugation the low speed pellet contained two medial-Golgi enzymes, N-acetylglucosaminyltransferase I and mannosidase II, but no enzymes or markers from other parts of the Golgi apparatus. Both were present in the same structures which appeared, by electron microscopy, to be small remnants of cisternal membranes. The enzymes could be removed by treatment with low salt, leaving behind a salt pellet, which we term the matrix. Removal of salt caused specific re-binding of both enzymes to the matrix, with an apparent dissociation constant of 3 nM for mannosidase II. Re-binding was abolished by pretreatment of intact Golgi stacks with proteinase K, suggesting that the matrix was present between the cisternae. PMID:8106542

Vertically polarizing undulator with dynamic compensation of magnetic forces

DOE PAGES

Strelnikov, N.; Vasserman, I.; Xu, J.; ...

2017-01-20

As part of the R&D program of the LCLS-II project, a novel 3.4-meter-long undulator prototype with horizontal magnetic field and dynamic force compensation has recently been developed at the Advanced Photon Source (APS). Some previous steps in this development were the shorter 0.8-meter-long and 2.8-meter-long prototypes. Extensive mechanical and magnetic testing was carried out for each prototype, and each prototype was magnetically tuned using magnetic shims. Furthermore, the resulting performance of the 3.4-meter-long undulator prototype meets all requirements for the LCLS-II insertion device, including limits on the field integrals, phase errors, higher-order magnetic moments, and electron-beam trajectory for all operationalmore » gaps, as well as the reproducibility and accuracy of the gap settings.« less

Focused electron beam induced deposition of pure SIO II

NASA Astrophysics Data System (ADS)

Perentes, Alexandre; Hoffmann, Patrik; Munnik, Frans

2007-02-01

Focused electron beam induced processing (FEBID) equipments are the "all in one" tools for high resolution investigation, and modification of nano-devices. Focused electron beam induced deposition from a gaseous precursor usually results in a nano-composite sub-structured material, in which the interesting material is embedded in an amorphous carbonaceous matrix. Using the Hydrogen free tetraisocyanatosilane Si(NCO) 4 molecule as Si source, we show how a controlled oxygen flux, simultaneously injected with the precursor vapors, causes contaminants to vanish from the FEB deposits obtained and leads to the deposition of pure SiO II. The chemical composition of the FEBID material could be controlled from SiC IINO 3 to SiO II, the latter containing undetectable foreign element contamination. The [O II] / [TICS] ratio needed to obtain SiO II in our FEB deposition equipment is larger than 300. The evolution of the FEBID material chemical composition is presented as function of the [O II] / [TICS] molecular flux ratios. A hypothetical decomposition pathway of this silane under these conditions is discussed based on the different species formed under electron bombardment of TICS. Transmission electron microscopy investigations demonstrated that the deposited oxide is smooth (roughness sub 2nm) and amorphous. Infrared spectroscopy confirmed the low concentration of hydroxyl groups. The Hydrogen content of the deposited oxide, measured by elastic recoil detection analysis, is as low as 1 at%. 193nm wavelength AIMS investigations of 125nm thick SiO II pads (obtained with [O II] / [TICS] = 325) showed an undetectable light absorption.

Electron loss from hydrogen-like highly charged ions in collisions with electrons, protons and light atoms

NASA Astrophysics Data System (ADS)

Lyashchenko, K. N.; Andreev, O. Yu; Voitkiv, A. B.

2018-03-01

We consider electron loss from a hydrogen-like highly charged ion (HCI) in relativistic collisions with hydrogen and helium in the range of impact velocities v min ≤ v ≤ v max (v min and v max correspond to the threshold energy ε th for electron loss in collisions with a free electron and to ≈5 ε th, respectively) where any reliable data for loss cross sections are absent. In this range, where the loss process is characterized by large momentum transfers, we express it in terms of electron loss in collisions with equivelocity protons and electrons and explore by performing a detailed comparative study of these subprocesses. Our results, in particular, show that: (i) compared to equivelocity electrons protons are more effective in inducing electron loss, (ii) the relative effectiveness of electron projectiles grows with increase in the atomic number of a HCI, (iii) collisions with protons and electrons lead to a qualitatively different population of the final-state-electron momentum space and even when the total loss cross sections in these collisions become already equal the spectra of the outgoing electrons still remain quite different in almost the entire volume of the final-state-electron momentum space, (iv) in collisions with hydrogen and helium the contributions to the loss process from the interactions with the nucleus and the electron(s) of the atom could be rather well separated in a substantial part of the final-state-electron momentum space.

Interfacial charge separation and recombination in InP and quasi-type II InP/CdS core/shell quantum dot-molecular acceptor complexes.

PubMed

Wu, Kaifeng; Song, Nianhui; Liu, Zheng; Zhu, Haiming; Rodríguez-Córdoba, William; Lian, Tianquan

2013-08-15

Recent studies of group II-VI colloidal semiconductor heterostuctures, such as CdSe/CdS core/shell quantum dots (QDs) or dot-in-rod nanorods, show that type II and quasi-type II band alignment can facilitate electron transfer and slow down charge recombination in QD-molecular electron acceptor complexes. To explore the general applicability of this wave function engineering approach for controlling charge transfer properties, we investigate exciton relaxation and dissociation dynamics in InP (a group III-V semiconductor) and InP/CdS core/shell (a heterostructure beween group III-V and II-VI semiconductors) QDs by transient absorption spectroscopy. We show that InP/CdS QDs exhibit a quasi-type II band alignment with the 1S electron delocalized throughout the core and shell and the 1S hole confined in the InP core. In InP-methylviologen (MV(2+)) complexes, excitons in the QD can be dissociated by ultrafast electron transfer to MV(2+) from the 1S electron level (with an average time constant of 11.4 ps) as well as 1P and higher electron levels (with a time constant of 0.39 ps), which is followed by charge recombination to regenerate the complex in its ground state (with an average time constant of 47.1 ns). In comparison, InP/CdS-MV(2+) complexes show similar ultrafast charge separation and 5-fold slower charge recombination rates, consistent with the quasi-type II band alignment in these heterostructures. This result demonstrates that wave function engineering in nanoheterostructures of group III-V and II-VI semiconductors provides a promising approach for optimizing their light harvesting and charge separation for solar energy conversion applications.

40 CFR Appendix II to Part 600 - Sample Fuel Economy Calculations

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 29 2010-07-01 2010-07-01 false Sample Fuel Economy Calculations II Appendix II to Part 600 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) ENERGY POLICY FUEL ECONOMY AND CARBON-RELATED EXHAUST EMISSIONS OF MOTOR VEHICLES Pt. 600, App. II Appendix II to Part 600—Sample Fuel Economy Calculations (...

10 CFR Appendix II to Part 504 - Fuel Price Computation

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 4 2013-01-01 2013-01-01 false Fuel Price Computation II Appendix II to Part 504 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS EXISTING POWERPLANTS Pt. 504, App. II Appendix II to Part... effects of future real price increases for each fuel. The delivered price of an alternate fuel used to...

10 CFR Appendix II to Part 504 - Fuel Price Computation

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 4 2014-01-01 2014-01-01 false Fuel Price Computation II Appendix II to Part 504 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS EXISTING POWERPLANTS Pt. 504, App. II Appendix II to Part... (APXi). If an alternate fuel other than coal is proposed the source or the derivation of the index must...

10 CFR Appendix II to Part 504 - Fuel Price Computation

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 4 2011-01-01 2011-01-01 false Fuel Price Computation II Appendix II to Part 504 Energy DEPARTMENT OF ENERGY (CONTINUED) ALTERNATE FUELS EXISTING POWERPLANTS Pt. 504, App. II Appendix II to Part... effects of future real price increases for each fuel. The delivered price of an alternate fuel used to...

Medical Malpractice in Dermatology-Part I: Reducing the Risks of a Lawsuit.

PubMed

Shah, Vidhi V; Kapp, Marshall B; Wolverton, Stephen E

2016-12-01

Malpractice risk is a common source of concern for the practicing physician. Dermatologists experience fewer lawsuits than most other specialists in medicine, but the risk is not negligible. All physicians should familiarize themselves with areas of potential risk and avoid medico-legal pitfalls. We present Part I of a two-part series addressing medico-legal questions common to most practitioners that cause a great deal of anxiety. Part I will focus upon risk management and prevention of future malpractice lawsuits, and Part II deals with suggestions and guidance once a lawsuit occurs. Herein, we discuss the primary sources of malpractice lawsuits delivered against healthcare practitioners including issues with informed consent, patient noncompliance, medical negligence, and inappropriate documentation, including use of electronic medical records. The overall goal is to effectively avoid these common sources of litigation. The risk management strategies discussed in this paper are relevant to the everyday practitioner and may offer physicians some degree of protection from potential liability.

The relevance of the Hippocratic Oath to the ethical and moral values of contemporary medicine. Part II: interpretation of the Hippocratic Oath-today's perspective.

PubMed

Askitopoulou, Helen; Vgontzas, Antonis N

2018-05-21

This is the second part of a paper on the relevance and significance of the Hippocratic Oath to modern medical ethical and moral values with the aim at answering questions on controversial issues related to the Oath. Part I argued that the general attributes and ethical values of the Oath are relevant to the modern world. Part II attempts to elucidate the interpretation of the specific injunctions of the Oath from today's perspective in relation to ethical values concerning the duties of physicians to patients and society. The objective is to prove that the Oath has established the general context of medical ethics of the physician-patient relationship, which reflects long-lasting moral values that still define the medical profession. The Oath has exemplified the fundamental modern ethical principles of beneficence, non-maleficence and confidentiality. Its foremost message focuses on patients' best interests and not on the prohibition of surgery, euthanasia or abortion, as is generally believed. Furthermore, the Oath as a code of professional identity has had a powerful impact on modem judicial opinions regarding medical ethics. In a lot of ways, it is as relevant of the values of contemporary medicine as it was for ancient medicine. These slides can be retrieved under Electronic Supplementary Material.

Electronic properties of electron and hole in type-II semiconductor nano-heterostructures

NASA Astrophysics Data System (ADS)

Rahul, K. Suseel; Souparnika, C.; Salini, K.; Mathew, Vincent

2016-05-01

In this project, we record the orbitals of electron and hole in type-II (CdTe/CdSe/CdTe/CdSe) semiconductor nanocrystal using effective mass approximation. In type-II the band edges of both valance and conduction band are higher than that of shell. So the electron and hole get confined in different layers of the hetero-structure. The energy eigen values and eigen functions are calculated by solving Schrodinger equation using finite difference matrix method. Based on this we investigate the effect of shell thickness and well width on energy and probability distribution of ground state (1s) and few excited states (1p,1d,etc). Our results predict that, type-II quantum dots have significant importance in photovoltaic applications.

SALT long-slit spectroscopy of CTS C30.10: two-component Mg II line

NASA Astrophysics Data System (ADS)

Modzelewska, J.; Czerny, B.; Hryniewicz, K.; Bilicki, M.; Krupa, M.; Świȩtoń, A.; Pych, W.; Udalski, A.; Adhikari, T. P.; Petrogalli, F.

2014-10-01

Context. Quasars can be used as a complementary tool to SN Ia to probe the distribution of dark energy in the Universe by measuring the time delay of the emission line with respect to the continuum. The understanding of the Mg II emission line structure is important for cosmological application and for the black hole mass measurements of intermediate redshift quasars. Aims: Knowing the shape of Mg II line and its variability allows for identifying which part of the line should be used to measure the time delay and the black hole mass. We thus aim at determining the structure and the variability of the Mg II line, as well as the underlying Fe II pseudo-continuum. Methods: We performed five spectroscopic observations of a quasar CTS C30.10 (z = 0.9000) with the SALT telescope between December 2012 and March 2014, and we studied the variations in the spectral shape in the 2700 Å-2900 Å rest frame. Results: We show that the Mg II line in this source consists of two kinematic components, which makes the source representative of type B quasars. Both components were modeled well with a Lorentzian shape, and they vary in a similar way. The Fe II contribution seems to be related only to the first (blue) Mg II component. Broad band spectral fitting instead favor the use of the whole line profile. The contribution of the narrow line region to Mg II is very low, below 2%. The Mg II variability is lower than the variability of the continuum, which is consistent with the simple reprocessing scenario. The variability level of CTS C30.10 and the measurement accuracy of the line and continuum is high enough to expect that further monitoring will allow the time delay between the Mg II line and continuum to be measured. Based on observations made with the Southern African Large Telescope (SALT) under program 2012-2-POL-003 and 2013-1-POL-RSA-002 (PI: B. Czerny).Spectra shown in Figs. 3 and 4 are only available in electronic form at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (ftp://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/570/A53Table 1 is available in electronic form at http://www.aanda.org

AN IMAGING STUDY OF A COMPLEX SOLAR CORONAL RADIO ERUPTION

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

Feng, S. W.; Chen, Y.; Song, H. Q.

2016-08-10

Solar coronal radio bursts are enhanced radio emission excited by energetic electrons accelerated during solar eruptions. Studying these bursts is important for investigating the origin and physical mechanism of energetic particles and further diagnosing coronal parameters. Earlier studies suffered from a lack of simultaneous high-quality imaging data of the radio burst and the eruptive structure in the inner corona. Here we present a study on a complex solar radio eruption consisting of a type II burst and three reversely drifting type III bursts, using simultaneous EUV and radio imaging data. It is found that the type II burst is closelymore » associated with a propagating and evolving CME-driven EUV shock structure, originated initially at the northern shock flank and later transferred to the top part of the shock. This source transfer is coincident with the presence of shock decay and enhancing signatures observed at the corresponding side of the EUV front. The electron energy accelerated by the shock at the flank is estimated to be ∼0.3 c by examining the imaging data of the fast-drifting herringbone structure of the type II burst. The reverse-drifting type III sources are found to be within the ejecta and correlated with a likely reconnection event therein. The implications for further observational studies and relevant space weather forecasting techniques are discussed.« less

Pulmonary haptoglobin (pHp) is part of the surfactant system in the human lung.

PubMed

Abdullah, Mahdi; Goldmann, Torsten

2012-11-20

Since the existence of pHp was demonstrated, it has been shown that this molecule and its receptor CD163 are regulated by different stimuli. Furthermore, a comparably fast secretion of pHp was described as well as the immuno-stimulatory effects. The intention of this study was to elucidate the role of pHp in the human lungs further. Here we show, by means of confocal microscopy and immune-electron-microscopy, a clear co-localization of pHp with surfactant protein-B in lamellar bodies of alveolar epithelial cells type II. These results are underlined by immunohistochemical stainings in differently fixed human lung tissues, which show pHp in vesicular and released form. The images of the released form resemble the intended position of surfactant in the human alveolus. pHp is secreted by Alveolar epithelial cells type II as previously shown. Moreover, pHp is co-localized with Surfactant protein-B. We conclude that the presented data shows that pHp is a native part of the surfactant system in the human lung. http://www.diagnosticpathology.diagnomx.eu/vs/2563584738239912.

Synthesis, characterization, antimicrobial activity and DFT studies of 2-(pyrimidin-2-ylamino)naphthalene-1,4-dione and its Mn(II), Co(II), Ni(II) and Zn(II) complexes

NASA Astrophysics Data System (ADS)

Chioma, Festus; Ekennia, Anthony C.; Ibeji, Collins U.; Okafor, Sunday N.; Onwudiwe, Damian C.; Osowole, Aderoju A.; Ujam, Oguejiofo T.

2018-07-01

A pyrimidine-based ligand, 2-(pyrimidin-2-ylamino)naphthalene-1,4-dione (L), has been synthesized by the reaction of 2-aminopyrimidine with 2-hydroxy-1,4-napthoquinone. Reaction of the ligand with Ni(II), Co(II), Mn(II) and Zn(II) acetate gave the corresponding metal complexes which were characterized by spectroscopic techniques, (infrared, electronic), elemental analysis, room-temperature magnetometry, conductance measurements and thermogravimetry-differential scanning calorimetry (TG-DSC) analyses. The room-temperature magnetic data and electronic spectral measurements of the complexes gave evidence of 4-coordinate square planar/tetrahedral geometry. The thermal analyses values obtained indicated the monohydrate complexes. The antimicrobial screening of the compounds showed mild to very good results. The Mn(II) complex showed the best result within in the range of 11.5-29 mm. The electronic, structural and spectroscopic properties of the complexes were further discussed using density functional theory. Molecular docking studies showed significant binding affinity with the drug targets and the metal complexes have potentials to be used as drugs.

Theoretical modeling of the electronic structure and exchange interactions in Cu(II)Pc

NASA Astrophysics Data System (ADS)

Wu, Wei; Fisher, A. J.; Harrison, N. M.; Wang, Hai; Wu, Zhenlin; Gardener, Jules; Heutz, Sandrine; Jones, Tim; Aeppli, Gabriel

2012-12-01

We calculate the electronic structure and exchange interactions in a copper(II)phthalocyanine (Cu(II)Pc) crystal as a one-dimensional molecular chain using hybrid exchange density functional theory (DFT). In addition, the intermolecular exchange interactions are also calculated in a molecular dimer using Green's function perturbation theory (GFPT) to illustrate the underlying physics. We find that the exchange interactions depend strongly on the stacking angle, but weakly on the sliding angle (defined in the text). The hybrid DFT calculations also provide an insight into the electronic structure of the Cu(II)Pc molecular chain and demonstrate that on-site electron correlations have a significant effect on the nature of the ground state, the band gap and magnetic excitations. The exchange interactions predicted by our DFT calculations and GFPT calculations agree qualitatively with the recent experimental results on newly found η-Cu(II)Pc and the previous results for the α- and β-phases. This work provides a reliable theoretical basis for the further application of Cu(II)Pc to molecular spintronics and organic-based quantum information processing.

Theoretical modeling of the electronic structure and exchange interactions in a Cu(II)Pc one-dimensional chain

NASA Astrophysics Data System (ADS)

Wu, Wei; Fisher, A. J.; Harrison, N. M.

2011-07-01

We calculate the electronic structure and exchange interactions in a copper(II)phthalocyanine [Cu(II)Pc] crystal as a one-dimensional molecular chain using hybrid exchange density functional theory (DFT). In addition, the intermolecular exchange interactions are also calculated in a molecular dimer using Green’s function perturbation theory (GFPT) to illustrate the underlying physics. We find that the exchange interactions depend strongly on the stacking angle, but weakly on the sliding angle (defined in the text). The hybrid DFT calculations also provide an insight into the electronic structure of the Cu(II)Pc molecular chain and demonstrate that on-site electron correlations have a significant effect on the nature of the ground state, the band gap, and magnetic excitations. The exchange interactions predicted by our DFT calculations and GFPT calculations agree qualitatively with the recent experimental results on newly found η-Cu(II)Pc and the previous results for the α and β phases. This work provides a reliable theoretical basis for the further application of Cu(II)Pc to molecular spintronics and organic-based quantum information processing.

10 CFR Appendix II to Part 960 - NRC and EPA Requirements for Preclosure Repository Performance

Code of Federal Regulations, 2012 CFR

2012-01-01

... 10 Energy 4 2012-01-01 2012-01-01 false NRC and EPA Requirements for Preclosure Repository Performance II Appendix II to Part 960 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Pt. 960, App. II Appendix II to Part 960—NRC and...

10 CFR Appendix II to Part 960 - NRC and EPA Requirements for Preclosure Repository Performance

Code of Federal Regulations, 2011 CFR

2011-01-01

... 10 Energy 4 2011-01-01 2011-01-01 false NRC and EPA Requirements for Preclosure Repository Performance II Appendix II to Part 960 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Pt. 960, App. II Appendix II to Part 960—NRC and...

10 CFR Appendix II to Part 960 - NRC and EPA Requirements for Preclosure Repository Performance

Code of Federal Regulations, 2013 CFR

2013-01-01

... 10 Energy 4 2013-01-01 2013-01-01 false NRC and EPA Requirements for Preclosure Repository Performance II Appendix II to Part 960 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Pt. 960, App. II Appendix II to Part 960—NRC and...

10 CFR Appendix II to Part 960 - NRC and EPA Requirements for Preclosure Repository Performance

Code of Federal Regulations, 2014 CFR

2014-01-01

... 10 Energy 4 2014-01-01 2014-01-01 false NRC and EPA Requirements for Preclosure Repository Performance II Appendix II to Part 960 Energy DEPARTMENT OF ENERGY GENERAL GUIDELINES FOR THE PRELIMINARY SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Pt. 960, App. II Appendix II to Part 960—NRC and...

Creep mechanisms of a new Ni-Co-base disc superalloy at an intermediate temperature.

PubMed

Yuan, Y; Gu, Y F; Zhong, Z H; Osada, T; Cui, C Y; Tetsui, T; Yokokawa, T; Harada, H

2012-10-01

The microstructures of a new Ni-Co-base disc superalloy, TMW-4M3, before and after the creep test at 725 °C/630 MPa have been systematically investigated by transmission electron microscopy (TEM). The crept microstructures were marked as three different deformation stages (I, II and III) corresponding to the gradually increased strain. At stage I, stacking fault (SF) shearing was the main deformation mechanism. The SF was extrinsic and lay on {111} plane. However, deformation microtwinning became the dominant mode at stage II and III. The average spacing of deformation twins decreased from 109 ± 15 nm at stage II to 76 ± 12 nm at stage III, whereas the twin thickness did not change significantly. The influence of stacking fault energy (SFE) of γ matrix on the deformation mechanism is discussed. It is suggested that lower SFE in TMW-4M3 is partly responsible for the enhanced creep resistance. © 2012 The Authors Journal of Microscopy © 2012 Royal Microscopical Society.

The prototype cameras for trans-Neptunian automatic occultation survey

NASA Astrophysics Data System (ADS)

Wang, Shiang-Yu; Ling, Hung-Hsu; Hu, Yen-Sang; Geary, John C.; Chang, Yin-Chang; Chen, Hsin-Yo; Amato, Stephen M.; Huang, Pin-Jie; Pratlong, Jerome; Szentgyorgyi, Andrew; Lehner, Matthew; Norton, Timothy; Jorden, Paul

2016-08-01

The Transneptunian Automated Occultation Survey (TAOS II) is a three robotic telescope project to detect the stellar occultation events generated by TransNeptunian Objects (TNOs). TAOS II project aims to monitor about 10000 stars simultaneously at 20Hz to enable statistically significant event rate. The TAOS II camera is designed to cover the 1.7 degrees diameter field of view of the 1.3m telescope with 10 mosaic 4.5k×2k CMOS sensors. The new CMOS sensor (CIS 113) has a back illumination thinned structure and high sensitivity to provide similar performance to that of the back-illumination thinned CCDs. Due to the requirements of high performance and high speed, the development of the new CMOS sensor is still in progress. Before the science arrays are delivered, a prototype camera is developed to help on the commissioning of the robotic telescope system. The prototype camera uses the small format e2v CIS 107 device but with the same dewar and also the similar control electronics as the TAOS II science camera. The sensors, mounted on a single Invar plate, are cooled to the operation temperature of about 200K as the science array by a cryogenic cooler. The Invar plate is connected to the dewar body through a supporting ring with three G10 bipods. The control electronics consists of analog part and a Xilinx FPGA based digital circuit. One FPGA is needed to control and process the signal from a CMOS sensor for 20Hz region of interests (ROI) readout.

Laser-induced breakdown spectroscopy (LIBS) analysis of calcium ions dissolved in water using filter paper substrates: an ideal internal standard for precision improvement.

PubMed

Choi, Daewoong; Gong, Yongdeuk; Nam, Sang-Ho; Han, Song-Hee; Yoo, Jonghyun; Lee, Yonghoon

2014-01-01

We report an approach for selecting an internal standard to improve the precision of laser-induced breakdown spectroscopy (LIBS) analysis for determining calcium (Ca) concentration in water. The dissolved Ca(2+) ions were pre-concentrated on filter paper by evaporating water. The filter paper was dried and analyzed using LIBS. By adding strontium chloride to sample solutions and using a Sr II line at 407.771 nm for the intensity normalization of Ca II lines at 393.366 or 396.847 nm, the analysis precision could be significantly improved. The Ca II and Sr II line intensities were mapped across the filter paper, and they showed a strong positive shot-to-shot correlation with the same spatial distribution on the filter paper surface. We applied this analysis approach for the measurement of Ca(2+) in tap, bottled, and ground water samples. The Ca(2+) concentrations determined using LIBS are in good agreement with those obtained from flame atomic absorption spectrometry. Finally, we suggest a homologous relation of the strongest emission lines of period 4 and 5 elements in groups IA and IIA based on their similar electronic structures. Our results indicate that the LIBS can be effectively applied for liquid analysis at the sub-parts per million level with high precision using a simple drying of liquid solutions on filter paper and the use of the correct internal standard elements with the similar valence electronic structure with respect to the analytes of interest.

Investigation of Electron Loss Processes in CO2/He/N2 Electric Discharges.

DTIC Science & Technology

1980-12-01

Background......................4 Structure of a Discharge. ............. 4 Electron Kinetics..................7 Plasma Chemistry .................. 14...Electron Kinetic Reactions. ............ 11 II C 2/IN 2/He Electron Kinetics ............ 15 III Plasma Chemistry Reactions. ............ 17 IV...effects (Ref 2:317- 323). Table II also lists some of the reactions they found to be possibly important. Plasma Chemistry In order to understand what is

Electronic structure and chemical bonding of the electron-poor II-V semiconductors ZnSb and ZnAs

NASA Astrophysics Data System (ADS)

Benson, Daryn; Sankey, Otto F.; Häussermann, Ulrich

2011-09-01

The binary compounds ZnSb and ZnAs with the CdSb structure are semiconductors (II-V), although the average electron concentration (3.5 per atom) is lower than that of the tetrahedrally bonded III-V and II-VI archetype systems (four per atom). We report a detailed electronic structure and chemical bonding analysis for ZnSb and ZnAs based on first-principles calculations. ZnSb and ZnAs are compared to the zinc blende-type semiconductors GaSb, ZnTe, GaAs, and ZnSe, as well as the more ionic, hypothetical, II-V systems MgSb and MgAs. We establish a clearly covalent bonding scenario for ZnSb and ZnAs where multicenter bonded structural entities (rhomboid rings Zn2Sb2 and Zn2As2) are connected to each other by classical two-center, two-electron bonds. This bonding scenario is only compatible with a weak ionicity in II-V semiconductor systems, and weak ionicity appears as a necessary condition for the stability of the CdSb structure type. It is argued that a chemical bonding scenario with mixed multicenter and two-center bonding resembles that of boron and boron-rich compounds and is typical of electron-poor sp-bonded semiconductors with average valence electron concentrations below four per atom.

Experimental electron energy-loss spectra and cross sections for the 4/2/S - 4/2/P transition in Zn II

NASA Technical Reports Server (NTRS)

Chutjian, A.; Newell, W. R.

1982-01-01

Electron energy-loss spectra and differential cross sections are reported for inelastic scattering from Zn II. Measurements were carried out in a crossed electron beam-ion beam apparatus, at incident electron energies of 30, 40, 50, 60, 75, 85, and 100 eV, and at a scattering angle of 14 deg. The present results are the first reported measurements of inelastic electron scattering from an ion.

Impact of nitrophenols on the photosynthetic electron transport chain and ATP content in Nostoc muscorum and Chlorella vulgaris.

PubMed

Umamaheswari, A; Venkateswarlu, K

2004-06-01

Concentration-dependent inhibition of the photosynthetic electron transport chain (photosystem I (PS I), photosystem II (PS II) and whole chain reaction) and ATP content was observed in Nostoc muscorum and Chlorella vulgaris grown with o-nitrophenol, m-nitrophenol, or 2,4-dinitrophenol. Although the extents of inhibition of the photosynthetic electron transport chain in both organisms were similar, PS II was more sensitive than PS I and whole chain reaction to the nitrophenols. Depletion of the ATP pool was noted in nitrophenol-grown cultures, probably as a consequence of nearly complete inhibition of the photosynthetic electron transport chain.

Determination and prediction of the magnetic anisotropy of Mn ions.

PubMed

Duboc, Carole

2016-10-24

This tutorial is dedicated to the investigation of magnetic anisotropy using both electron paramagnetic resonance (EPR) spectroscopy for its experimental determination and quantum chemistry for its theoretical prediction. Such an approach could lead to the definition of magneto-structural correlation essential for the rational design of complexes with targeted magnetic properties or for the identification of unknown reactive metallic species involved in catalysis. To illustrate this combined approach the high spin Mn II , Mn III and Mn IV ions have been taken as specific examples. The first part deals with the analysis of the EPR experiments as a function of the ions under investigation and the conditions of the measurements, specifically: (i) EPR spectra recorded under high vs. low frequency conditions with respect to magnetic anisotropy, (ii) EPR spectra of non-integer (Kramers) vs. integer (non-Kramers) spin states and (iii) mono- vs. multi-frequency EPR spectra. In the second part, two main quantum chemical approaches, which have proven their capability to predict magnetic anisotropy, are described. More importantly, these calculations give access to the different contributions of zero field splitting, key information for the full understanding of magnetic anisotropy. The last part demonstrates that such a combined experimental and theoretical approach allows for the definition of magneto-structural correlations.

The ELISE II Project: A Digital Image Library for Europe.

ERIC Educational Resources Information Center

Strunz, Bob; Waters, Mairead

This paper describes the progress made under the ELISE II electronic image library project from a technical standpoint. The ELISE II project is a European-wide initiative that aims to provide a comprehensive electronic image library service for Europe. It is funded under the European Commission, DG XIII-E, Telematics for Libraries Initiative. The…

Mononuclear Copper Complex Catalyzed Four-Electron Reduction of Oxygen

PubMed Central

Fukuzumi, Shunichi; Kotani, Hiroaki; Lucas, Heather R.; Doi, Kaoru; Suenobu, Tomoyoshi; Peterson, Ryan L.; Karlin, Kenneth D.

2010-01-01

A mononuclear CuII complex acts as an efficient catalyst for four-electron reduction of O2 to H2O by a ferrocene derivative via formation of the dinuclear CuII peroxo complex that is further reduced in the presence of protons by a ferrocene derivative to regenerate the CuII complex. PMID:20443560

24-epibrassinolide and 20-hydroxyecdysone affect photosynthesis differently in maize and spinach.

PubMed

Rothová, Olga; Holá, Dana; Kočová, Marie; Tůmová, Lenka; Hnilička, František; Hniličková, Helena; Kamlar, Marek; Macek, Tomáš

2014-07-01

The aim of the work was to examine the effect of brassinosteroid (24-epibrassinolide; 24E) and ecdysteroid (20-hydroxyecdysone; 20E) on various parts of primary photosynthetic processes in maize and spinach. Additionally, the effect of steroids on gaseous exchange, pigment content and biomass accumulation was studied. The efficiency of the photosynthetic whole electron-transport chain responded negatively to the 24E or 20E treatment in both species, but there were interspecific differences regarding Photosystem (PS) II response. A positive effect on its oxygen-evolving complex and a slightly better energetical connectivity between PSII units were observed in maize whereas the opposite was true for spinach. The size of the pool of the PSI end electron acceptors was usually diminished due to 24E or 20E treatment. The treatment of plants with 24E or 20E applied individually positively influenced the content of photosynthetic pigments in maize (not in spinach). On the other hand, it did not affect gaseous exchange in maize but resulted in its reduction in spinach. Plants treated with combination of both steroids mostly did not significantly differ from the control plants. We have demonstrated for the first time that 20E applied in low (10nM) concentration can affect various parts of photosynthetic processes similarly to 24E and that brassinosteroids regulate not only PSII but also other parts of the photosynthetic electron transport chain - but not necessarily in the same way. Copyright © 2014 Elsevier Inc. All rights reserved.

A first principles investigation of electron transfer between Fe(II) and U(VI) on insulating Al- vs. semiconducting Fe-oxide surfaces via the proximity effect

NASA Astrophysics Data System (ADS)

Taylor, S. D.; Marcano, M. C.; Becker, U.

2017-01-01

This study investigates how the intrinsic chemical and electronic properties of mineral surfaces and their associated electron transfer (ET) pathways influence the reduction of U(VI) by surface-associated Fe(II). Density functional theory (DFT), including the Hubbard U correction to the exchange-correlation functional, was used to investigate sorption/redox reactions and ET mechanisms between Fe(II) and U(VI) coadsorbed on isostructural, periodic (0 0 1) surfaces of the insulator corundum (α-Al2O3) vs. the semiconductor hematite (α-Fe2O3). Furthermore, the coadsorbed Fe(II) and U(VI) ions are spatially separated from one another on the surfaces (⩾5.9 Å) to observe whether electronic-coupling through the semiconducting hematite surface facilitates ET between the adsorbates, a phenomenon known as the proximity effect. The calculations show that the different chemical and electronic properties between the isostructural corundum and hematite (0 0 1) surfaces lead to considerably different ET mechanisms between Fe(II) and U(VI). ET on the insulating corundum (0 0 1) surface is limited by the adsorbates' structural configuration. When Fe(II) and U(VI) are spatially separated and do not directly interact with one another (e.g. via an inner-sphere complex), U(VI) reduction by Fe(II) cannot occur as there is no physical pathway enabling ET between the adsorbates. In contrast to the insulating corundum (0 0 1) surface, the hematite (0 0 1) surface can potentially participate in ET reactions due to the high number of electron acceptor sites from the Fe d-states near the Fermi level at the hematite surface. The adsorption of Fe(II) also introduces d-states near the Fermi level as well as shifts unoccupied d-states of the Fe cations at the hematite surface to lower energies, making the surface more conductive. In turn, electronic coupling through the surface can link the spatially separated adsorbates to one another and provide distinct ET pathways for an electron from Fe(II) to travel through the hematite surface and reach U(VI). The progression and extent of ET occurring on the semiconducting hematite (0 0 1) surface via the proximity effect depends on the electronic properties of the surface. ET between the spatially separated U(VI) and Fe(II) occurs most readily when orbitals between the Fe and U adsorbates overlap with those of neighboring O and Fe ions at the hematite surface, as shown by calculations without the Hubbard U correction. Analyses of the spins densities confirm that the U and Fe adsorbates were reduced and oxidized, respectively, (acquiring 0.33 μB and 0.11-0.20 μB, respectively), while Fe cations at the hematite surface were reduced (losing ⩽0.6 μB). If electrons are highly localized, the amount of orbital mixing and electronic coupling through the hematite surface decreases and in turn leads to a lower degree of spin transfer, as predicted by calculations with the Hubbard U correction. Thus, the proximity effect is a potential mechanism on semiconducting surfaces facilitating surface-mediated redox reactions, although its significance varies depending on the electronic properties and subsequent charge-carrying ability of the surface. These results provide insight into ET pathways and mechanisms on insulating Al- and semiconducting Fe oxide surfaces influencing the reduction U(VI) by Fe(II) that may subsequently limit uranium's transport in the subsurface.

Manganese binding properties of human calprotectin under conditions of high and low calcium: X-ray crystallographic and advanced electron paramagnetic resonance spectroscopic analysis.

PubMed

Gagnon, Derek M; Brophy, Megan Brunjes; Bowman, Sarah E J; Stich, Troy A; Drennan, Catherine L; Britt, R David; Nolan, Elizabeth M

2015-03-04

The antimicrobial protein calprotectin (CP), a hetero-oligomer of the S100 family members S100A8 and S100A9, is the only identified mammalian Mn(II)-sequestering protein. Human CP uses Ca(II) ions to tune its Mn(II) affinity at a biologically unprecedented hexahistidine site that forms at the S100A8/S100A9 interface, and the molecular basis for this phenomenon requires elucidation. Herein, we investigate the remarkable Mn(II) coordination chemistry of human CP using X-ray crystallography as well as continuous-wave (CW) and pulse electron paramagnetic resonance (EPR) spectroscopies. An X-ray crystallographic structure of Mn(II)-CP containing one Mn(II), two Ca(II), and two Na(I) ions per CP heterodimer is reported. The CW EPR spectrum of Ca(II)- and Mn(II)-bound CP prepared with a 10:0.9:1 Ca(II):Mn(II):CP ratio is characterized by an unusually low zero-field splitting of 485 MHz (E/D = 0.30) for the S = 5/2 Mn(II) ion, consistent with the high symmetry of the His6 binding site observed crystallographically. Results from electron spin-echo envelope modulation and electron-nuclear double resonance experiments reveal that the six Mn(II)-coordinating histidine residues of Ca(II)- and Mn(II)-bound CP are spectroscopically equivalent. The observed (15)N (I = 1/2) hyperfine couplings (A) arise from two distinct classes of nitrogen atoms: the coordinating ε-nitrogen of the imidazole ring of each histidine ligand (A = [3.45, 3.71, 5.91] MHz) and the distal δ-nitrogen (A = [0.11, 0.18, 0.42] MHz). In the absence of Ca(II), the binding affinity of CP for Mn(II) drops by two to three orders of magnitude and coincides with Mn(II) binding at the His6 site as well as other sites. This study demonstrates the role of Ca(II) in enabling high-affinity and specific binding of Mn(II) to the His6 site of human calprotectin.

Collisional excitation and radiative properties of N II - The strong intercombination (1D - 3P0) transition at 748 A

NASA Technical Reports Server (NTRS)

Tripp, T. M.; Shemansky, D. E.; James, G. K.; Ajello, J. M.

1991-01-01

Laboratory measurements of EUV emission from electron-excited N2 have been obtained at medium resolution, providing N II EUV emission cross section measurements and allowing the confirmation of recent calculations by Fawcett (1987) indicating the presence of a strong intercombination line in N II at 748.37 A. The most recently available data are used to predict the basic collisional and radiative properties of N II, the plasma diagnostic properties are briefly explored, and radiative cooling coefficients are given. Some basic properties of electron-excited N II and N2 are examined in the EUV in order to diagnose emission spectra of the earth and Titan. The N II emissions in the earth dayglow, particularly at 916 A, are much brighter than current estimates of source rates. The N II 1085 A line in the dayglow contains a significant component from dissociative photoionization excitation. The N II 1085 A, 916 A, and 670 A lines in the Titan dayglow spectrum appear to be compatible with direct electron excitation of N2.

Tentative anatomy of ZnS-type electroluminescence

NASA Astrophysics Data System (ADS)

Bringuier, E.

1994-05-01

The paper reviews the electrical and optical mechanisms at work in sulfide-based thin-film electroluminescence display devices within the framework of general semiconductor physics. The electrical problem is twofold: (i) charge carriers are sourced at high electric field in a nominally insulating material, the carrier density increasing by almost eight orders of magnitude; (ii) the carriers are transported at high field, with an average energy largely exceeding the thermal one. (i) Carrier sourcing is best understood from direct-current-driven ZnS films, and is ascribed to partly filled deep donors transferring electrons to the conduction band by Fowler-Nordheim tunneling. The deep donors also act as carrier sinkers, and evidence for space charge is afforded by small-signal impedance analysis disclosing a markedly inductive behavior. The conduction picture obtained from dc-driven films is then used to clarify the operation of alternating-current electroluminescence structures where the sulfide is sandwiched between two blocking oxide layers. The electrostatics of the ac structure is investigated in detail including space charge and field nonuniformity, and external observables are related to internal quantities. The simple model of interfacial carrier sourcing and sinking is examined. (ii) High-field electronic transport is controlled by the electron-phonon interaction, and the modeling resorts to numerical simulations or the lucky-drift concept. At low electron energies the interaction with phonons is predominantly polar, while at optical energies it proceeds via deformation potential scattering. In spite of the uncertainties in transport models in that range, it is likely that ˜50% of the electrons overtake 2 eV at the usual operating fields in ZnS. Light emission is associated with impurity luminescence centers embedded in the sulfide host. They are excited while current is flowing, and the ensuing relaxation is partly radiative. We describe the two ways in which an impurity may be excited electrically, namely, impact excitation (internal promotion of the center to a state of higher energy) or impact ionization (with an electron released to the host conduction band). The actual excitation mechanism depends on the position of the impurity excited level relative to the host energy bands. A calculation of the excitation yield (number of excited centers per transferred electron) is detailed in the case of impact excitation. Lastly, a phenomenological description of the various relaxation channels is given in terms of formal kinetics, and the relative importance of radiative relaxation is assessed by means of the deexcitation yield (fraction of centers decaying radiatively), which is defined in the case of the impulse response.

Direct measurements of intramolecular electron transfer rates between cytochrome c and cytochrome c peroxidase: effects of exothermicity and primary sequence on rate

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

Cheung, E.; Taylor, K.; Kornblatt, J.A.

1986-03-01

Rapid mixing of ferrocytochrome c peroxidase (cyt c peroxidase(II)) and ferricytochrome c (cyt c(III)) results in the reduction of cyt c(III) by cyt c peroxidase(II). In 10 mM phosphate, pH 7.0, the rate of decay of cyt c peroxidase(II) and the rate of accumulation of cyt c(II) give equal first-order rate constants. Equivalent results are obtained by pulse radiolysis using isopropanol radical as the reducing agent. This rate is independent of the initial cyt c(III):cyt c peroxidase(II) ratios. These results are consistent with unimolecular electron transfer occurring within a cyt c(III)-cyt c peroxidase(II) complex. When cyt c is replaced bymore » porphyrin cyt c (iron-free cyt c), a complex still forms with cyt c peroxidase. On radiolysis intracomplex electron transfer occurs from the porphyrin cyt c anion radical to cyt c peroxidase(III). This large rate increase suggest that the barrier for intracomplex electron transfer is large. Finally, the authors have briefly investigated how the cyt c peroxidase(II) ..-->.. cyt c(III) rate depends on the primary structure of cyt c(III). They find the reactivity order to be as follows: yeast > horse > tuna.« less

Surface Mn(II) oxidation actuated by a multicopper oxidase in a soil bacterium leads to the formation of manganese oxide minerals

PubMed Central

Zhang, Zhen; Zhang, Zhongming; Chen, Hong; Liu, Jin; Liu, Chang; Ni, Hong; Zhao, Changsong; Ali, Muhammad; Liu, Fan; Li, Lin

2015-01-01

In this manuscript, we report that a bacterial multicopper oxidase (MCO266) catalyzes Mn(II) oxidation on the cell surface, resulting in the surface deposition of Mn(III) and Mn(IV) oxides and the gradual formation of bulky oxide aggregates. These aggregates serve as nucleation centers for the formation of Mn oxide micronodules and Mn-rich sediments. A soil-borne Escherichia coli with high Mn(II)-oxidizing activity formed Mn(III)/Mn(IV) oxide deposit layers and aggregates under laboratory culture conditions. We engineered MCO266 onto the cell surfaces of both an activity-negative recipient and wild-type strains. The results confirmed that MCO266 governs Mn(II) oxidation and initiates the formation of deposits and aggregates. By contrast, a cell-free substrate, heat-killed strains, and intracellularly expressed or purified MCO266 failed to catalyze Mn(II) oxidation. However, purified MCO266 exhibited Mn(II)-oxidizing activity when combined with cell outer membrane component (COMC) fractions in vitro. We demonstrated that Mn(II) oxidation and aggregate formation occurred through an oxygen-dependent biotic transformation process that requires a certain minimum Mn(II) concentration. We propose an approximate electron transfer pathway in which MCO266 transfers only one electron to convert Mn(II) to Mn(III) and then cooperates with other COMC electron transporters to transfer the other electron required to oxidize Mn(III) to Mn(IV). PMID:26039669

Surface Mn(II) oxidation actuated by a multicopper oxidase in a soil bacterium leads to the formation of manganese oxide minerals.

PubMed

Zhang, Zhen; Zhang, Zhongming; Chen, Hong; Liu, Jin; Liu, Chang; Ni, Hong; Zhao, Changsong; Ali, Muhammad; Liu, Fan; Li, Lin

2015-06-03

In this manuscript, we report that a bacterial multicopper oxidase (MCO266) catalyzes Mn(II) oxidation on the cell surface, resulting in the surface deposition of Mn(III) and Mn(IV) oxides and the gradual formation of bulky oxide aggregates. These aggregates serve as nucleation centers for the formation of Mn oxide micronodules and Mn-rich sediments. A soil-borne Escherichia coli with high Mn(II)-oxidizing activity formed Mn(III)/Mn(IV) oxide deposit layers and aggregates under laboratory culture conditions. We engineered MCO266 onto the cell surfaces of both an activity-negative recipient and wild-type strains. The results confirmed that MCO266 governs Mn(II) oxidation and initiates the formation of deposits and aggregates. By contrast, a cell-free substrate, heat-killed strains, and intracellularly expressed or purified MCO266 failed to catalyze Mn(II) oxidation. However, purified MCO266 exhibited Mn(II)-oxidizing activity when combined with cell outer membrane component (COMC) fractions in vitro. We demonstrated that Mn(II) oxidation and aggregate formation occurred through an oxygen-dependent biotic transformation process that requires a certain minimum Mn(II) concentration. We propose an approximate electron transfer pathway in which MCO266 transfers only one electron to convert Mn(II) to Mn(III) and then cooperates with other COMC electron transporters to transfer the other electron required to oxidize Mn(III) to Mn(IV).

Strain Measurements within Fibre Boards. Part II: Strain Concentrations at the Crack Tip of MDF Specimens Tested by the Wedge Splitting Method

PubMed Central

Sinn, Gerhard; Müller, Ulrich; Konnerth, Johannes; Rathke, Jörn

2012-01-01

This is the second part of an article series where the mechanical and fracture mechanical properties of medium density fiberboard (MDF) were studied. While the first part of the series focused on internal bond strength and density profiles, this article discusses the fracture mechanical properties of the core layer. Fracture properties were studied with a wedge splitting setup. The critical stress intensity factors as well as the specific fracture energies were determined. Critical stress intensity factors were calculated from maximum splitting force and two-dimensional isotropic finite elements simulations of the specimen geometry. Size and shape of micro crack zone were measured with electronic laser speckle interferometry. The process zone length was approx. 5 mm. The specific fracture energy was determined to be 45.2 ± 14.4 J/m2 and the critical stress intensity factor was 0.11 ± 0.02 MPa.

Photosystems and global effects of oxygenic photosynthesis.

PubMed

Nelson, Nathan

2011-08-01

Because life on earth is governed by the second law of thermodynamics, it is subject to increasing entropy. Oxygenic photosynthesis, the earth's major producer of both oxygen and organic matter, is a principal player in the development and maintenance of life, and thus results in increased order. The primary steps of oxygenic photosynthesis are driven by four multi-subunit membrane protein complexes: photosystem I, photosystem II, cytochrome b(6)f complex, and F-ATPase. Photosystem II generates the most positive redox potential found in nature and thus capable of extracting electrons from water. Photosystem I generates the most negative redox potential found in nature; thus, it largely determines the global amount of enthalpy in living systems. The recent structural determination of PSII and PSI complexes from cyanobacteria and plants sheds light on the evolutionary forces that shaped oxygenic photosynthesis. This newly available structural information complements knowledge gained from genomic and proteomic data, allowing for a more precise description of the scenario in which the evolution of life systems took place. This article is part of a Special Issue entitled: Regulation of Electron Transport in Chloroplasts. Copyright © 2010 Elsevier B.V. All rights reserved.

Zn(II), Cd(II) and Hg(I) complexes of cinnamic acid: FT-IR, FT-Raman, 1H and 13C NMR studies

NASA Astrophysics Data System (ADS)

Kalinowska, M.; Świsłocka, R.; Lewandowski, W.

2011-05-01

The effect of zinc, cadmium(II) and mercury(I) ions on the electronic structure of cinnamic acid (phenylacrylic acid) was studied. In this research many miscellaneous analytical methods, which complement one another, were used: infrared (FT-IR), Raman (FT-Raman), nuclear magnetic resonance ( 1H, 13C NMR) and quantum mechanical calculations. The spectroscopic studies provide some knowledge on the distribution of the electronic charge in molecule, the delocalization energy of π-electrons and the reactivity of metal complexes. In the series of Zn(II) → Cd(II) → Hg(I) cinnamates: (1) systematic shifts of several bands in the experimental and theoretical IR and Raman spectra and (2) regular chemical shifts for protons 1H and 13C nuclei were observed.

A hyperspectral view of Cassiopeia A

NASA Astrophysics Data System (ADS)

Alarie, Alexandre; Bilodeau, Antoine; Drissen, Laurent

2014-07-01

We used the imaging Fourier transform spectrometer Spectromètre Imageur de l'Observatoire du Mont-Mégantic (SpIOMM) to obtain hyperspectral cubes of the young supernova remnant Cassiopeia A (Cas A). The cubes contain over 5000 spatially resolved spectra covering the spectral range 6480-7050 Å. We first investigate the slow-moving N-rich quasi-stationary flocculi by measuring their radial velocity as well as the [N II] λ6583/Hα ratio. No correlation between their radial velocity and [N II] λ6583/Hα ratio with their location has been found. We used multi-epoch observations from the Hubble Space Telescope to create a proper motion map, showing the displacement of several filaments over the most part of Cas A. Combining data from SpIOMM and Hubble, we re-evaluate the distance to Cas A and obtained 3.33 ± 0.10 kpc, which is in good agreement with previous estimates. Finally, we obtain a three-dimensional spatial view of the [S II] λλ6716, 6731 emissions showing their location, expansion velocity and the [S II] doublet line ratio for multiple locations in the remnant. The velocity asymmetry reported by previous analyses is clearly visible. Also, the [S II] doublet ratio (with a mean value of 0.5 ± 0.2) indicates a very high and variable electronic density throughout the remnant.

A representative survey of the dynamics and energetics of FR II radio galaxies

NASA Astrophysics Data System (ADS)

Ineson, J.; Croston, J. H.; Hardcastle, M. J.; Mingo, B.

2017-05-01

We report the first large, systematic study of the dynamics and energetics of a representative sample of Fanaroff-Riley type II (FR II) radio galaxies with well-characterized group/cluster environments. We used X-ray inverse-Compton and radio synchrotron measurements to determine the internal radio-lobe conditions, and these were compared with external pressures acting on the lobes, determined from measurements of the thermal X-ray emission of the group/cluster. Consistent with previous work, we found that FR II radio lobes are typically electron dominated by a small factor relative to equipartition, and are overpressured relative to the external medium in their outer parts. These results suggest that there is typically no energetically significant proton population in the lobes of FR II radio galaxies (unlike for FR Is), and so for this population, inverse-Compton modelling provides an accurate way of measuring total energy content and estimating jet power. We estimated the distribution of Mach numbers for the population of expanding radio lobes, finding that at least half of the radio galaxies are currently driving strong shocks into their group/cluster environments. Finally, we determined a jet power-radio luminosity relation for FR II radio galaxies based on our estimates of lobe internal energy and Mach number. The slope and normalization of this relation are consistent with theoretical expectations, given the departure from equipartition and environmental distribution for our sample.

40 CFR Appendixes I-Ii to Part 268 - [Reserved

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 26 2010-07-01 2010-07-01 false [Reserved] I Appendixes I-II to Part 268 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) LAND DISPOSAL RESTRICTIONS Appendixes I-II to Part 268 [Reserved] ...

40 CFR Appendixes I-Ii to Part 268 - [Reserved

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 27 2011-07-01 2011-07-01 false [Reserved] I Appendixes I-II to Part 268 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) LAND DISPOSAL RESTRICTIONS Appendixes I-II to Part 268 [Reserved] ...

40 CFR Appendixes I-Ii to Part 268 - [Reserved

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 27 2014-07-01 2014-07-01 false [Reserved] I Appendixes I-II to Part 268 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) LAND DISPOSAL RESTRICTIONS Appendixes I-II to Part 268 [Reserved] ...

40 CFR Appendixes I-Ii to Part 268 - [Reserved

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 28 2012-07-01 2012-07-01 false [Reserved] I Appendixes I-II to Part 268 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) LAND DISPOSAL RESTRICTIONS Appendixes I-II to Part 268 [Reserved] ...

40 CFR Appendixes I-Ii to Part 268 - [Reserved

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 28 2013-07-01 2013-07-01 false [Reserved] I Appendixes I-II to Part 268 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) SOLID WASTES (CONTINUED) LAND DISPOSAL RESTRICTIONS Appendixes I-II to Part 268 [Reserved] ...

2015 Progress Report/July 2016: Iron Oxide Redox Transformation Pathways: The Bulk Electrical Conduction Mechanism

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

Scherer, Michelle M.; Rosso, Kevin M.

Despite decades of research on the reactivity and stable isotope properties of Fe oxides, the ability to describe the redox behavior of Fe oxides in the environment is still quite limited. This is due, in large part, to the analytical and spatial complexities associated with studying microscopic processes at the Fe oxide-water interface. This project had the long-term vision of filling this gap by developing a detailed understanding of the relationship between interfacial ET processes, surface structure and charge, and mineral semiconducting properties. We focused on the Fe(III)-oxides and oxyhydroxides because of their geochemical preponderance, versatility in synthesis of compositionally,more » structurally, and morphologically tailored phases, and because they are amenable to a wide range of surface and bulk properties characterization. In particular, reductive transformation of phases such as hematite (α-Fe 2O 3) and goethite (α-FeOOH) in aqueous solution can serve as excellent model systems for studies of electron conduction processes, as well as provide valuable insights into effect of nanoscale conductive materials on contaminant fate at DOE sites. More specifically, the goal of the Iowa component of this project was to use stable Fe isotope measurements to simultaneously measure isotope specific oxidation states and concentrations of Fe at the hematite-water and goethite-water interface. This work builds on our previous work where we used an innovative combination of 57Fe Mössbauer spectroscopy and high precision isotope ratio measurements (MC-ICP-MS) to probe the dynamics of the reaction of aqueous Fe(II) with goethite. Mössbauer spectroscopy detects 57Fe only among all other Fe isotopes and we have capitalized on this to spectroscopically demonstrate Fe(II)-Fe(III) electron transfer between sorbed Fe(II) and Fe(III) oxides (Handler, et al., 2009; Gorski, et al. 2010; Rosso et al., 2010). By combining the Mössbauer spectroscopy and stable isotopes measurements, we have been able to simultaneously track the oxidation state and isotope concentration of the bulk Fe oxide and aqueous Fe. One of our most compelling findings is that despite the apparent stability of the Fe(II)-goethite system, there is actually a tremendous amount of Fe atom cycling occurring between the aqueous phase and the bulk goethite as indicated by the isotopic composition of both phases approaching the mass balance average (Handler et al., 2009). How such extensive re-crystallization and Fe atom exchange can occur with no significant morphological change is a fascinating question. Based on previous work from PI Rosso’s group showing that a potential gradient across hematite crystal faces leads to conduction through hematite and growth and dissolution at separate crystal faces we proposed that a redox-driven recrystallization could be occurring that would explain the extensive mixing observed with the isotope data. From our previous studies utilizing Mössbauer spectroscopy, we know that sorption of Fe(II) onto goethite results in electron transfer between the sorbed Fe(II) and the structural Fe(III) in goethite. Oxidation of the sorbed Fe(II) produces growth of goethite on goethite (i.e., homoepitaxy), as well as injection of an electron into goethite. It is possible that electron transfer from sorbed Fe(II) occurs across a potential gradient, and that Fe(II) atoms are dissolved at a different location on the goethite surface. These newly-reduced Fe(II) atoms could then dissolve into the aqueous phase, exposing fresh Fe(III) goethite to the aqueous phase. Through a repeated series of these five steps of sorption–electron transfer–crystal growth–conduction– dissolution, a redox-driven conveyor belt, could be established that would allow all of the goethite to be eventually exposed to the aqueous phase and exchanged. This surface-mediated recrystallization process would result in similar Fe isotope distributions in the aqueous phase and goethite particle, as we have observed here. It would also result in a stable aqueous Fe(II) concentration, if there were equal rates of goethite growth and dissolution.« less

Fundamentals of Condensed Matter Physics Marvin L. Cohen and Steven G. Louie

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

Devanathan, Ram

This graduate level textbook on Condensed Matter Physics is written lucidly by two leading luminaries in this field. The volume draws its material from the graduate course in condensed matter physics that has been offered by the authors for several decades at the University of California, Berkeley. Cohen and Louie have done an admirable job of guiding the reader gradually from elementary concepts to advanced topics. The book is divided into four main parts that have four chapters each. Chapter 1 presents models of solids in terms of interacting atoms, which is appropriate for the ground state, and excitations tomore » describe collective effects. Chapter 2 deals with the properties of electrons in crystalline materials. The authors introduce the Born-Oppenheimer approximation and then proceed to the periodic potential approximation. Chapter 3 discusses energy bands in materials and covers concepts from the free electron model to the tight binding model and periodic boundary conditions. Chapter 4 starts with fixed atomic cores and introduces lattice vibrations, phonons, and the concept of density of states. By the end of this part, the student should have a basic understanding of electrons and phonons in materials. Part II presents electron dynamics and the response of materials to external probes. Chapter 5 covers the effective Hamiltonian approximation and the motion of the electron under a perturbation, such as an external field. The discussion moves to many-electron interactions and the exchange-correlation energy in Chapter 6, the widely-used Density Functional Theory (DFT) in chapter 7, and the dielectric response function in Chapter 8. The next two parts of the book cover advanced topics. Part III begins with a discussion of the response of materials to photons in Chapter 9. Chapter 10 goes into the details of electron-phonon interactions in different materials and introduces the polaron. Chapter 11 presents electron dynamics in a magnetic field and Chapter 12 discusses electrical and thermal transport in materials. Part IV takes the reader further into many body effects, superconductivity, and nanoscale materials. The authors introduce Feynman diagrams and many-body perturbation theory in Chapter 13, theories of superconductivity in Chapter 14, magnetism in Chapter 15, and low dimensional systems in Chapter 16. The first two parts are required reading for the beginner planning to perform DFT calculations. The advanced student interested in conducting research in condensed matter physics will benefit from continuing on to the last two parts. There is a set of problems at the end of each part. The narrative is aided by equations and detailed figures. References at the end of the book direct the reader to relevant books and review articles for each chapter. The inside covers include a periodic table and a useful list of fundamental physical constants. The authors present the underlying mathematics elegantly, which makes the textbook quite readable for those with a good mathematical background. Students lacking a firm footing in math will find the terrain rough after Chapter 1. This field has seen many good undergraduate textbooks including those by Kittel and by Ashcroft and Mermin. This volume fills the need for a rigorous graduate level textbook, and is a required addition to the bookshelf of every condensed matter physicist. Cohen and Louie have brought refreshing clarity to a challenging subject and made it eminently accessible to the motivated student.« less

An Analysis of a Finite Element Method for Convection-Diffusion Problems. Part II. A Posteriori Error Estimates and Adaptivity.

DTIC Science & Technology

1983-03-01

AN ANALYSIS OF A FINITE ELEMENT METHOD FOR CONVECTION- DIFFUSION PROBLEMS PART II: A POSTERIORI ERROR ESTIMATES AND ADAPTIVITY by W. G. Szymczak Y 6a...PERIOD COVERED AN ANALYSIS OF A FINITE ELEMENT METHOD FOR final life of the contract CONVECTION- DIFFUSION PROBLEM S. Part II: A POSTERIORI ERROR ...Element Method for Convection- Diffusion Problems. Part II: A Posteriori Error Estimates and Adaptivity W. G. Szvmczak and I. Babu~ka# Laboratory for

Electronic refractive index changes and measurement of saturation intensity in Cr3+-doped YAG crystal

NASA Astrophysics Data System (ADS)

Kesavulu, C. R.; Moncorgé, R.; Fromager, M.; Ait-Ameur, K.; Catunda, T.

2018-04-01

The electronic refractive index variation is associated with the difference in the polarizabilities (Δαp) of the Cr3+ ion in its ground and excited states. In order to further address the physical origin of Δαp in a Cr3+-doped YAG crystal, time-resolved Z-scan measurements were performed and analyzed at λ = 457 nm by using a chopped Ar+ ion laser. It is found a nonlinear refractive index with the real and imaginary parts n2‧ = 2.2 × 10-8 cm2/W and n2‧‧ = 2.8 × 10-10 cm2/W, respectively. The real part is associated with a polarizability difference Δαp = 2.2 × 10-25 cm3. The imaginary part indicates that excited state absorption (ESA) occurs and that Cr:YAG behaves as a saturable absorber. The transient response of the Z-scan signal decreases with the laser intensity as τ-1 = τo-1(1+I/Is), where τo is the excited state lifetime and Is the saturation intensity. By measuring this transient response at different laser intensities, it was possible to confirm the τo value which can be derived from fluorescence measurements and to determine a Is value of 8.3 kW/cm2.

Electron spin echo envelope modulation studies of the Cu(II)-substituted derivative of isopenicillin N synthase: A structural and spectroscopic model

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

Feng Jiang; Peisach, J.; Lijune Ming

Electron spin echo envelope modulation spectroscopy (ESEEM) was used to study the active site structure of isopenicillin N synthase (IPNS) from Cephalosporium acremonium with Cu(II) as a spectroscopic probe. Fourier transform of the simulated electron spin-echo envelope for the Cu(II)-substituted enzyme, Cu(II)IPNS, revealed two nearly magnetically equivalent, equatorially coordinated His imidazoles. The superhyperfine coupling constant, A{sub iso}, for the remote {sup 14}N of each imidazole was 1.65 MHz. The binding of substrate to the enzyme altered the magnetic coupling so that A{sub iso} is 1.30 MHz for one nitrogen and 2.16 MHz for the other. From a comparison of themore » ESSEM of Cu(II)IPNS in D{sub 2}O and H{sub 2}O, it is suggested that water is a ligand of Cu(II) and this is displaced upon the addition of substrate.« less

Substrate-controlled Rh(II)-catalyzed single-electron-transfer (SET): divergent synthesis of fused indoles.

PubMed

Chen, Kai; Zhu, Zi-Zhong; Liu, Jia-Xin; Tang, Xiang-Ying; Wei, Yin; Shi, Min

2016-01-07

Rh(II)-catalyzed diversified ring expansions controlled by single-electron-transfer (SET) have been disclosed in this communication, producing a series of indole-fused azetidines and 1H-carbazoles or related derivatives in moderate to good yields via Rh2(III,II) nitrene radical intermediates. The direction of ring expansion branches according to different ring sizes of methylenecycloalkanes.

Pulse-by-pulse energy measurement at the Stanford Linear Collider

NASA Astrophysics Data System (ADS)

Blaylock, G.; Briggs, D.; Collins, B.; Petree, M.

1992-01-01

The Stanford Linear Collider (SLC) collides a beam of electrons and positrons at 92 GeV. It is the first colliding linac, and produces Z(sup 0) particles for High-Energy Physics measurements. The energy of each beam must be measured to one part in 10(exp 4) on every collision (120 Hz). An Energy Spectrometer in each beam line after the collision produces two stripes of high-energy synchrotron radiation with critical energy of a few MeV. The distance between these two stripes at an imaging plane measures the beam energy. The Wire-Imaging Synchrotron Radiation Detector (WISRD) system comprises a novel detector, data acquisition electronics, readout, and analysis. The detector comprises an array of wires for each synchrotron stripe. The electronics measure secondary emission charge on each wire of each array. A Macintosh II (using THINK C, THINK Class Library) and DSP coprocessor (using ANSI C) acquire and analyze the data, and display and report the results for SLC operation.

Comparative absorption, electroabsorption and electrochemical studies of intervalence electron transfer and electronic coupling in cyanide-bridged bimetallic systems: ancillary ligand effects

NASA Astrophysics Data System (ADS)

Vance, Fredrick W.; Slone, Robert V.; Stern, Charlotte L.; Hupp, Joseph T.

2000-03-01

Electroabsorption or Stark spectroscopy has been used to evaluate the systems (NC) 5M II-CN-Ru III(NH 3) 51- and (NC) 5M II-CN-Ru III(NH 3) 4py 1-, where M II=Fe II or Ru II. When a pyridine ligand is present in the axial position on the Ru III acceptor, the effective optical electron transfer distance - as measured by the change in dipole moment, |Δ μ| - is increased by more than 35% relative to the ammine substituted counterpart. Comparison of the charge transfer distances to the crystal structure of Na[(CN) 5Fe-CN-Ru(NH 3) 4py] · 6H 2O reveals that the Stark derived distances are ˜50% to ˜90% of the geometric separation of the metal centers. The differences result in an upward revision in the Hush delocalization parameter, c b2, and of the electronic coupling matrix element, H ab, relative to those parameters obtained exclusively from electronic absorption measurements. The revised parameters are compared to those, which are obtained via electrochemical techniques and found to be in only fair agreement. We conclude that the absorption/electroabsorption analysis likely yields a more reliable set of mixing and coupling parameters.

Electron transfer flavoprotein domain II orientation monitored using double electron-electron resonance between an enzymatically reduced, native FAD cofactor, and spin labels

PubMed Central

Swanson, Michael A; Kathirvelu, Velavan; Majtan, Tomas; Frerman, Frank E; Eaton, Gareth R; Eaton, Sandra S

2011-01-01

Human electron transfer flavoprotein (ETF) is a soluble mitochondrial heterodimeric flavoprotein that links fatty acid β-oxidation to the main respiratory chain. The crystal structure of human ETF bound to medium chain acyl-CoA dehydrogenase indicates that the flavin adenine dinucleotide (FAD) domain (αII) is mobile, which permits more rapid electron transfer with donors and acceptors by providing closer access to the flavin and allows ETF to accept electrons from at least 10 different flavoprotein dehydrogenases. Sequence homology is high and low-angle X-ray scattering is identical for Paracoccus denitrificans (P. denitrificans) and human ETF. To characterize the orientations of the αII domain of P. denitrificans ETF, distances between enzymatically reduced FAD and spin labels in the three structural domains were measured by double electron-electron resonance (DEER) at X- and Q-bands. An FAD to spin label distance of 2.8 ± 0.15 nm for the label in the FAD-containing αII domain (A210C) agreed with estimates from the crystal structure (3.0 nm), molecular dynamics simulations (2.7 nm), and rotamer library analysis (2.8 nm). Distances between the reduced FAD and labels in αI (A43C) were between 4.0 and 4.5 ± 0.35 nm and for βIII (A111C) the distance was 4.3 ± 0.15 nm. These values were intermediate between estimates from the crystal structure of P. denitrificans ETF and a homology model based on substrate-bound human ETF. These distances suggest that the αII domain adopts orientations in solution that are intermediate between those which are observed in the crystal structures of free ETF (closed) and ETF bound to a dehydrogenase (open). PMID:21308847

Electron cyclotron emission from nonthermal tokamak plasmas

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

Harvey, R.W.; O'Brien, M.R.; Rozhdestvensky, V.V.

1993-02-01

Electron cyclotron emission can be a sensitive indicator of nonthermal electron distributions. A new, comprehensive ray-tracing and cyclotron emission code that is aimed at predicting and interpreting the cyclotron emission from tokamak plasmas is described. The radiation transfer equation is solved along Wentzel--Kramers--Brillouin (WKB) rays using a fully relativistic calculation of the emission and absorption from electron distributions that are gyrotropic and toroidally symmetric, but may be otherwise arbitrary functions of the constants of motion. Using a radial array of electron distributions obtained from a bounce-averaged Fokker--Planck code modeling dc electron field and electron cyclotron heating effects, the cyclotron emissionmore » spectra are obtained. A pronounced strong nonthermal cyclotron emission feature that occurs at frequencies relativistically downshifted to second harmonic cyclotron frequencies outside the tokamak is calculated, in agreement with experimental results from the DIII-D [J. L. Luxon and L. G. Davies, Fusion Technol. [bold 8], 441 (1985)] and FT-1 [D. G. Bulyginsky [ital et] [ital al]., in [ital Proceedings] [ital of] [ital the] 15[ital th] [ital European] [ital Conference] [ital on] [ital Controlled] [ital Fusion] [ital and] [ital Plasma] [ital Heating], Dubrovnik, 1988 (European Physical Society, Petit-Lancy, 1988), Vol. 12B, Part II, p. 823] tokamaks. The calculations indicate the presence of a strong loss mechanism that operates on electrons in the 100--150 keV energy range.« less

A Survey of Optometry Graduates to Determine Practice Patterns: Part II: Licensure and Practice Establishment Experiences.

ERIC Educational Resources Information Center

Bleimann, Robert L.; Smith, Lee W.

1985-01-01

A summary of Part II of a two-volume study of optometry graduates conducted by the Association of Schools and Colleges of Optometry is presented. Part II includes the analysis of the graduates' licensure and practice establishment experiences. (MLW)

Electronic monitoring and voice prompts improve hand hygiene and decrease nosocomial infections in an intermediate care unit.

PubMed

Swoboda, Sandra M; Earsing, Karen; Strauss, Kevin; Lane, Stephen; Lipsett, Pamela A

2004-02-01

To determine whether electronic monitoring of hand hygiene and voice prompts can improve hand hygiene and decrease nosocomial infection rates in a surgical intermediate care unit. Three-phase quasi-experimental design. Phase I was electronic monitoring and direct observation; phase II was electronic monitoring and computerized voice prompts for failure to perform hand hygiene on room exit; and phase III was electronic monitoring only. Nine-room, 14-bed intermediate care unit in a university, tertiary-care institution. All patient rooms, utility room, and staff lavatory were monitored electronically. All healthcare personnel including physicians, nurses, nursing support personnel, ancillary staff, all visitors and family members, and any other personnel interacting with patients on the intermediate care unit. All patients with an intermediate care unit length of stay >48 hrs were followed for nosocomial infection. Electronic monitoring during all phases, computerized voice prompts during phase II only. We evaluated a total of 283,488 electronically monitored entries into a patient room with 251,526 exits for 420 days (10,080 hrs and 3,549 patient days). Compared with phase I, hand hygiene compliance in patient rooms improved 37% during phase II (odds ratio, 1.38; 95% confidence interval, 1.04-1.83) and 41% in phase III (odds ratio, 1.41; 95% confidence interval, 1.07-1.84). When adjusting for patient admissions during each phase, point estimates of nosocomial infections decreased by 22% during phase II and 48% during phase III; when adjusting for patient days, the number of infections decreased by 10% during phase II and 40% during phase III. Although the overall rate of nosocomial infections significantly decreased when combining phases II and III, the association between nosocomial infection and individual phase was not significant. Electronic monitoring provided effective ongoing feedback about hand hygiene compliance. During both the voice prompt phase and post-intervention phase, hand hygiene compliance and nosocomial infection rates improved suggesting that ongoing monitoring and feedback had both a short-term and, perhaps, a longer-term effect.

Cysteine-grafted nonwoven geotextile: a new and efficient material for heavy metals sorption--Part B.

PubMed

Vandenbossche, M; Vezin, H; Touati, N; Jimenez, M; Casetta, M; Traisnel, M

2014-10-01

The development of a new material designed to trap heavy metals from sediments or wastewater, based on a polypropylene non-woven covalently grafted with cysteine, has been reported in a previous paper (Part A). The non-woven was first functionalized with acrylic acid (AA) which is used as spacer, and then cysteine was immobilized on the substrate through covalent coupling in order to obtain the so-called PP-g-AA-cysteine. Some preliminary heavy metals adsorption tests gave interesting results: at 20 °C for 24 h and in a 1000 mg/L heavy metals solution, PP-g-AA-cysteine adsorbs 95 mg Cu/g PP (CuSO4 solution), 104 mg Cu/g PP (Cu(NO3)2 solution), 135 mg Pb/g PP (Pb(NO3)2 solution) and 21 mg Cr/g PP (Cr(NO3)3 solution). In this second part of the work, heavy metals sorption tests were carried out with Cu (II), Pb (II), and Cr (III) separately, in order to determine the sorption capacity of this new sorbent as a function of (i) the heavy metals concentration in the solution, (ii) the contact time with the solution, (iii) the pH and (iv) the ionic strength of the solution containing heavy metals. Moreover, the sorption capacity of PP-g-AA-Cysteine was studied using a polluted solution consisting of a mixture of these different heavy metals. An Electron Paramagnetic Resonance study was finally carried out in order to determine the coordination geometry in the environment of the copper trapped by the PP-g-AA-cysteine. Copyright © 2014 Elsevier Ltd. All rights reserved.

Pulmonary haptoglobin (pHp) is part of the surfactant system in the human lung

PubMed Central

2012-01-01

Abstract Since the existence of pHp was demonstrated, it has been shown that this molecule and its receptor CD163 are regulated by different stimuli. Furthermore, a comparably fast secretion of pHp was described as well as the immuno-stimulatory effects. The intention of this study was to elucidate the role of pHp in the human lungs further. Here we show, by means of confocal microscopy and immune-electron-microscopy, a clear co-localization of pHp with Surfactant protein-B in lamellar bodies of Alveolar Epithelial Cells Type II. These results are underlined by immunohistochemical stainings in differently fixed human lung tissues, which show pHp in vesicular and released form. The images of the released form resemble the intended position of surfactant in the human alveolus. pHp is secreted by Alveolar epithelial cells type II as previously shown. Moreover, pHp is co-localized with Surfactant protein-B. We conclude that the presented data shows that pHp is a native part of the surfactant system in the human lung. Virtual slides http://www.diagnosticpathology.diagnomx.eu/vs/2563584738239912. PMID:23164167

Temperature Driven Topological Switch in 1T'-MoTe2 and Strain Induced Nematicity in NaFeAs

NASA Astrophysics Data System (ADS)

Berger, Ayelet Denise Notis

Quasiparticle interference (QPI) is a powerful technique within Scanning Tunneling Microscopy (STM) that is used to probe the electronic bandstructure of materials. This thesis presents two examples using QPI to measure the bandstructure in materials with exotic electronic states that can be tuned via outside parameters (temperature and strain). In Part I of the thesis, we discuss the temperature dependence of Fermi Arcs in 1T'-MoTe 2, and then in Part II, the strain dependent nematic state in NaFeAs. The recent discovery of Weyl semimetals has introduced a new family of materials with topologically protected electronic properties and potential applications due to their anomalous transport effects. Even more useful is a Weyl semimetal that can be turned "on" and "off," switching between a topological and trivial state. One possible material is MoTe2, which undergoes a phase transition at 240K. This thesis consists of experiments using Scanning Tunneling Microscopy (STM) and Spectroscopy (STS) at different temperatures to visualize changes in the electronic bandstructure of MoTe2 across the topological phase transition. We show that a signature of topologically protected Fermi Arcs is present at low temperatures but disappears at room temperature, in the trivial phase. We include an in-depth discussion of how to account for thermal effects when comparing these two types of measurements. In Part II, we discuss strain induced nematicity in NaFeAs, an iron pnictide. Nematic fluctuations and spin correlations play an important role in the phase diagram of the iron pnictides, a family of unconventional superconductors. Illuminating the mechanism behind this symmetry breaking is key to understanding the superconducting state. Previous work has shown that nematicity in the iron pnictides responds strongly to applied strain [1, 2]. In this thesis, I present results from a new experimental technique, elasto-scanning tunneling microscopy (E-STM), which combines in situ strain and atomic resolution STM/STS. For the first time, we are able to observe the effects of strain on nematicity at the local level. We perform E-STM measurements in both the spin density wave phase and the tetragonal phase of NaFeAs and measure a distinct response in each. We successfully use strain to manipulate domain boundaries in the spin density wave state and we find the intensity of nematic fluctuations is coupled to strain in NaFeAs in the tetragonal phase.

Phase Equilibria Diagrams Database

National Institute of Standards and Technology Data Gateway

SRD 31 NIST/ACerS Phase Equilibria Diagrams Database (PC database for purchase)   The Phase Equilibria Diagrams Database contains commentaries and more than 21,000 diagrams for non-organic systems, including those published in all 21 hard-copy volumes produced as part of the ACerS-NIST Phase Equilibria Diagrams Program (formerly titled Phase Diagrams for Ceramists): Volumes I through XIV (blue books); Annuals 91, 92, 93; High Tc Superconductors I & II; Zirconium & Zirconia Systems; and Electronic Ceramics I. Materials covered include oxides as well as non-oxide systems such as chalcogenides and pnictides, phosphates, salt systems, and mixed systems of these classes.

Interfacial charge separation and photovoltaic efficiency in Fe(ii)-carbene sensitized solar cells.

PubMed

Pastore, Mariachiara; Duchanois, Thibaut; Liu, Li; Monari, Antonio; Assfeld, Xavier; Haacke, Stefan; Gros, Philippe C

2016-10-12

The first combined theoretical and photovoltaic characterization of both homoleptic and heteroleptic Fe(ii)-carbene sensitized photoanodes in working dye sensitized solar cells (DSSCs) has been performed. Three new heteroleptic Fe(ii)-NHC dye sensitizers have been synthesized, characterized and tested. Despite an improved interfacial charge separation in comparison to the homoleptic compounds, the heteroleptic complexes did not show boosted photovoltaic performances. The ab initio quantitative analysis of the interfacial electron and hole transfers and the measured photovoltaic data clearly evidenced fast recombination reactions for heteroleptics, even associated with un unfavorable directional electron flow, and hence slower injection rates, in the case of homoleptics. Notably, quantum mechanics calculations revealed that deprotonation of the not anchored carboxylic function in the homoleptic complex can effectively accelerate the electron injection rate and completely suppress the electron recombination to the oxidized dye. This result suggests that introduction of strong electron-donating substituents on the not-anchored carbene ligand in heteroleptic complexes, in such a way of mimicking the electronic effects of the carboxylate functionality, should yield markedly improved interfacial charge generation properties. The present results, providing for the first time a detailed understanding of the interfacial electron transfers and photovoltaic characterization in Fe(ii)-carbene sensitized solar cells, open the way to a rational molecular engineering of efficient iron-based dyes for photoelectrochemical applications.

Lewis Acid-Induced Change from Four- to Two-Electron Reduction of Dioxygen Catalyzed by Copper Complexes Using Scandium Triflate

PubMed Central

Kakuda, Saya; Rolle, Clarence; Ohkubo, Kei; Siegler, Maxime A.; Karlin, Kenneth D.; Fukuzumi, Shunichi

2015-01-01

Mononuclear copper complexes, [(tmpa)CuII(CH3CN)](ClO4)2 (1, tmpa = tris(2-pyridylmethyl)amine) and [(BzQ)CuII(H2O)2](ClO4)2 (2, BzQ = bis(2-quinolinylmethyl)benzylamine)], act as efficient catalysts for the selective two-electron reduction of O2 by ferrocene derivatives in the presence of scandium triflate (Sc(OTf)3), in acetone, whereas 1 catalyzes the four-electron reduction of O2 by the same reductant in the presence of Brønsted acids such as triflic acid. Following formation of the peroxo-bridged dicopper(II) complex [(tmpa)CuII(O2)CuII(tmpa)]2+, the two-electron reduced product of O2 with Sc3+ is observed to be scandium peroxide ([Sc3+(O22−)]+). In the presence of three equiv of hexamethylphosphoric triamide (HMPA), [Sc3+(O22−)]+ was oxidized by [Fe(bpy)3]3+ (bpy = 2,2′-bipyridine) to the known superoxide species [(HMPA)3Sc3+(O2•−)]2+ as detected by EPR spectroscopy. A kinetic study revealed that the rate-determining step of the catalytic cycle for the two-electron reduction of O2 with 1 is electron transfer from Fc* to 1 to give a cuprous complex which is highly reactive toward O2, whereas the rate-determining step with 2 is changed to the reaction of the cuprous complex with O2 following electron transfer from ferrocene derivatives to 2. The explanation for the change in catalytic O2-reaction stoichiometry from four-electron with Brønsted acids to two-electron reduction in the presence of Sc3+ and also for the change in the rate-determining step is clarified based on a kinetics interrogation of the overall catalytic cycle as well as each step of the catalytic cycle with study of the observed effects of Sc3+ on copper-oxygen intermediates. PMID:25659416

Decoupling optical and potentiometric band gaps in pi-conjugated materials.

PubMed

Susumu, Kimihiro; Therien, Michael J

2002-07-24

Syntheses, optical spectroscopy, potentiometric studies, and electronic structural calculations are reported for two classes of conjugated (porphinato)metal oligomers that feature a meso-to-meso ethyne-bridged linkage topology. One set of these systems, bis[(5,5'-10,20-bis[3,5-bis(3,3-dimethyl-1-butyloxy)phenyl]porphinato)zinc(II)]ethyne (DD), 5,15-bis[[5'-10',20'-bis[3,5-di(3,3-dimethyl-1-butyloxy)phenyl]porphinato)zinc(II)]ethynyl]-10,20-bis[3,5-di(9-methoxy-1,4,7-trioxanonyl)phenyl]porphinato)zinc(II) (DDD), and 5,15-bis[[15' '-(5'-10',20'-bis[3,5-bis(3,3-dimethyl-1-butyloxy)phenyl]porphinato)zinc(II)]-[(5' '-10' ',20' '-bis[3,5-di(9-methoxy-1,4,7-trioxanonyl)phenyl]porphinato)zinc(II)]ethyne]ethynyl]-10,20-bis[3,5-di(9-methoxy-1,4,7-trioxanonyl)phenyl]porphinato)zinc(II) (DDDDD), constitute highly soluble analogues of previously studied examples of this structural motif having simple 10,20-diaryl substituents, while a corresponding set of conjugated oligomers, [(5-10,20-bis[3,5-bis(3,3-dimethyl-1-butyloxy)phenyl]porphinato)zinc(II)]-[(5'-15'-ethynyl-10',20'-bis[10,20-bis(heptafluoropropyl)porphinato)zinc(II)]ethyne (DA), 5,15-bis[[5'-10',20'-bis[3,5-di(3,3-dimethyl-1-butyloxy)phenyl]porphinato)zinc(II)]ethynyl]-10,20-bis(heptafluoropropyl)porphinato]zinc(II) (DAD), and 5,15-bis[[15' '-(5'-10',20'-bis[3,5-bis(3,3-dimethyl-1-butyloxy)phenyl]porphinato)zinc(II)]-[(5' '-(10' ',20' '-bis(heptafluoropropyl)porphinato)zinc(II)]ethyne]ethynyl]-10,20-bis[3,5-di(9-methoxy-1,4,7-trioxanonyl)phenyl]porphinato)zinc(II) (DADAD), features alternating electron-rich and electron-poor (porphinato)zinc(II) units. Electrooptic and computational data for these species demonstrate that it is possible to engineer conjugated oligomeric structures that possess highly delocalized singlet (S1) excited states yet manifest apparent one-electron oxidation and reduction potentials (E1/20/+ and E1/2-/0 values) that are essentially invariant with respect to those elucidated for their constituent monomeric precursors.

Quasiparticle scattering in type-II Weyl semimetal MoTe2

NASA Astrophysics Data System (ADS)

Lin, Chun-Liang; Arafune, Ryuichi; Minamitani, Emi; Kawai, Maki; Takagi, Noriaki

2018-03-01

The electronic structure of type-II Weyl semimetal molybdenum ditelluride (MoTe2) is studied by using scanning tunneling microscopy and density functional theory calculations. Through measuring energy-dependent quasiparticle interference (QPI) patterns with a cryogenic scanning tunneling microscope, several characteristic features are found in the QPI patterns. Two of them arise from the Weyl semimetal nature; one is the topological Fermi arc surface state and the other can be assigned to be a Weyl point. The remaining structures are derived from the scatterings relevant to the bulk electronic states. The findings lead to further understanding of the topological electronic structure of type-II Weyl semimetal MoTe2.

Quasiparticle scattering in type-II Weyl semimetal MoTe2.

PubMed

Lin, Chun-Liang; Arafune, Ryuichi; Minamitani, Emi; Kawai, Maki; Takagi, Noriaki

2018-02-15

The electronic structure of type-II Weyl semimetal molybdenum ditelluride (MoTe 2 ) is studied by using scanning tunneling microscopy and density functional theory calculations. Through measuring energy-dependent quasiparticle interference (QPI) patterns with a cryogenic scanning tunneling microscope, several characteristic features are found in the QPI patterns. Two of them arise from the Weyl semimetal nature; one is the topological Fermi arc surface state and the other can be assigned to be a Weyl point. The remaining structures are derived from the scatterings relevant to the bulk electronic states. The findings lead to further understanding of the topological electronic structure of type-II Weyl semimetal MoTe 2 .

Multimetallic Systems for the Photocatalytic Production of Fuels from Abundant Sources

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

Dunbar, Kim R.; Turro, Claudia

The reported findings herein are a result of a collaboration between the groups of Claudia Turro at The Ohio State University (DE-SC0010542) and Kim R. Dunbar at Texas A&M University (DE-SC0010721). The Turro and Dunbar groups jointly discovered that cationic d 7–d 7 Rh 2(II,II) complexes bridged by electron-donating formamidinate (form) ligands possess redox-active excited states that are relatively long-lived and can engage in charge transfer reactions. As part of the present grant we designed new complexes that exhibit strong absorption from the UV to ~800 nm. The Rh 2(II,II) complexes under investigation are poised to undergo catalytic reduction ofmore » substrates because they are robust to changes in metal oxidation state, the two metals and the two diimine ligands, together with the non-innocent bridges, can be used to store redox equivalents, making these complexes capable of coupling one-electron events with multi-electron transformations. We discovered the electrocatalytic reduction of H + and CO 2 by complexes that are able to electrocatalytically reduce H + to H 2 with high turnover frequencies (TOFs) and overpotentials, η, of ~0.5 V,8 as well as to reduce CO 2 to HCOOH. We now have experimental evidence that both the production of H 2 from H + and HCOOH. The molecular catalysts are stable after the acid and/or CO 2 is consumed since electrocatalysis is restored at the same rate upon the addition of substrate to the cell.8,9 Moreover, we showed that the catalysis is not a result of a decomposition product deposited on the electrode, since placing an electrode from an active electrocatalytic solution into one that does not contain catalyst completely shuts down the reactivity. We are currently exploring the reactivity of these complexes in hydride transfer reactions with other substrates and in the presence of CO 2 and reducing agents, as well as attempting to grow single crystals for x-ray diffraction.« less

Family Finance Education; An Interdisciplinary Approach. Volume II.

ERIC Educational Resources Information Center

Gibbs, Mary S., Ed.; And Others, Eds.

Volume II of a two-part series related to family finance education provides materials for study and discussion in the 1968 workshop. In Part I, members of the advisory council present their viewpoints concerning an interdisciplinary approach to education in family finance. Part II presents basic and current information related to principal areas…

Spraying Brassinolide improves Sigma Broad tolerance in foxtail millet (Setaria italica L.) through modulation of antioxidant activity and photosynthetic capacity.

PubMed

Yuan, Xiang-Yang; Zhang, Li-Guang; Huang, Lei; Yang, Hui-Jie; Zhong, Yan-Ting; Ning, Na; Wen, Yin-Yuan; Dong, Shu-Qi; Song, Xi-E; Wang, Hong-Fu; Guo, Ping-Yi

2017-09-11

To explore the role of Brassinolide (BR) in improving the tolerance of Sigma Broad in foxtail millet (Setaria italica L.), effects of 0.1 mg/L of BR foliar application 24 h before 3.37 g/ha of Sigma Broad treatment at five-leaf stage of foxtail millet on growth parameters, antioxidant enzymes, malondialdehyde (MDA), chlorophyll, net photosynthetic rate (P N ), chlorophyll fluorescence and P 700 parameters were studied 7 and 15 d after herbicide treatment, respectively. Results showed that Sigma Broad significantly decreased plant height, activities of superoxide dismutase (SOD), chlorophyll content, P N , PS II effective quantum yield (Y (II)), PS II electron transport rate (ETR (II)), photochemical quantum yield of PSI(Y (I)) and PS I electron transport rate ETR (I), but significantly increased MDA. Compared to herbicide treatment, BR dramatically increased plant height, activities of SOD, Y (II), ETR (II), Y (I) and ETR (I). This study showed BR pretreatment could improve the tolerance of Sigma Broad in foxtail millet through improving the activity of antioxidant enzymes, keeping electron transport smooth, and enhancing actual photochemical efficiency of PS II and PSI.

Efficient Simulation of Secondary Fluorescence Via NIST DTSA-II Monte Carlo.

PubMed

Ritchie, Nicholas W M

2017-06-01

Secondary fluorescence, the final term in the familiar matrix correction triumvirate Z·A·F, is the most challenging for Monte Carlo models to simulate. In fact, only two implementations of Monte Carlo models commonly used to simulate electron probe X-ray spectra can calculate secondary fluorescence-PENEPMA and NIST DTSA-II a (DTSA-II is discussed herein). These two models share many physical models but there are some important differences in the way each implements X-ray emission including secondary fluorescence. PENEPMA is based on PENELOPE, a general purpose software package for simulation of both relativistic and subrelativistic electron/positron interactions with matter. On the other hand, NIST DTSA-II was designed exclusively for simulation of X-ray spectra generated by subrelativistic electrons. NIST DTSA-II uses variance reduction techniques unsuited to general purpose code. These optimizations help NIST DTSA-II to be orders of magnitude more computationally efficient while retaining detector position sensitivity. Simulations execute in minutes rather than hours and can model differences that result from detector position. Both PENEPMA and NIST DTSA-II are capable of handling complex sample geometries and we will demonstrate that both are of similar accuracy when modeling experimental secondary fluorescence data from the literature.

Synthesis, spectroscopic, thermal and anticancer studies of metal-antibiotic chelations: Ca(II), Fe(III), Pd(II) and Au(III) chloramphenicol complexes

NASA Astrophysics Data System (ADS)

Al-Khodir, Fatima A. I.; Refat, Moamen S.

2016-09-01

Four Ca(II), Fe(III), Pd(II) and Au(III) complexes of chloramphenicol drug have been synthesized and well characterized using elemental analyses, (infrared, electronic, and 1H-NMR) spectra, magnetic susceptibility measurement, and thermal analyses. Infrared spectral data show that the chloramphenicol drug coordinated to Ca(II), Pd(II) and Au(III) metal ions through two hydroxyl groups with 1:1 or 1:2 M ratios, but Fe(III) ions chelated towards chloramphenicol drug via the oxygen and nitrogen atoms of amide group with 1:2 ratio based on presence of keto↔enol form. The X-ray powder diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM) techniques were used to identify the nano-size particles of both iron(III) and gold(III) chloramphenicol complexes. The antimicrobial assessments of the chloramphenicol complexes were scanned and collected the results against of some kind of bacteria and fungi. The cytotoxic activity of the gold(III) complex was tested against the human colon carcinoma (HCT-116) and human hepatocellular carcinoma (HepG-2) tumor cell lines.

Controlled Vectorial Electron Transfer and Photoelectrochemical Applications of Layered Relay/Photosensitizer-Imprinted Au Nanoparticle Architectures on Electrodes.

PubMed

Metzger, Tzuriel S; Tel-Vered, Ran; Willner, Itamar

2016-03-23

Two configurations of molecularly imprinted bis-aniline-bridged Au nanoparticles (NPs) for the specific binding of the electron acceptor N,N'-dimethyl-4,4'-bipyridinium (MV(2+) ) and for the photosensitizer Zn(II)-protoporphyrin IX (Zn(II)-PP-IX) are assembled on electrodes, and the photoelectrochemical features of the two configurations are discussed. Configuration I includes the MV(2+) -imprinted Au NPs matrix as a base layer, on which the Zn(II)-PP-IX-imprinted Au NPs layer is deposited, while configuration II consists of a bilayer corresponding to the reversed imprinting order. Irradiation of the two electrodes in the presence of a benzoquinone/benzohydroquinone redox probe yields photocurrents of unique features: (i) Whereas configuration I yields an anodic photocurrent, the photocurrent generated by configuration II is cathodic. (ii) The photocurrents obtained upon irradiation of the imprinted electrodes are substantially higher as compared to the nonimprinted surfaces. The high photocurrents generated by the imprinted Au NPs-modified electrodes are attributed to the effective loading of the imprinted matrices with the MV(2+) and Zn(II)-PP-IX units and to the effective charge separation proceeding in the systems. The directional anodic/cathodic photocurrents are rationalized in terms of vectorial electron transfer processes dictated by the imprinting order and by the redox potentials of the photosensitizer/electron acceptor units associated with the imprinted sites in the two configurations. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Pentacyanoiron(II) as an electron donor group for nonlinear optics: medium-responsive properties and comparisons with related pentaammineruthenium(II) complexes.

PubMed

Coe, Benjamin J; Harries, Josephine L; Helliwell, Madeleine; Jones, Lathe A; Asselberghs, Inge; Clays, Koen; Brunschwig, Bruce S; Harris, James A; Garín, Javier; Orduna, Jesús

2006-09-20

In this article, we describe a series of complex salts in which electron-rich {Fe(II)(CN)(5)}(3)(-) centers are coordinated to pyridyl ligands with electron-accepting N-methyl/aryl-pyridinium substituents. These compounds have been characterized by using various techniques including electronic absorption spectroscopy and cyclic voltammetry. Molecular quadratic nonlinear optical (NLO) responses have been determined by using hyper-Rayleigh scattering (HRS) at 1064 nm, and also via Stark (electroabsorption) spectroscopic studies on the intense, visible d --> pi* metal-to-ligand charge-transfer (MLCT) bands. The relatively large static first hyperpolarizabilities, beta(0), increase markedly on moving from aqueous to methanol solutions, accompanied by large red-shifts in the MLCT transitions. Acidification of aqueous solutions allows reversible switching of the linear and NLO properties, as shown via both HRS and Stark experiments. Time-dependent density functional theory and finite field calculations using a polarizable continuum model yield relatively good agreement with the experimental results and confirm the large decrease in beta(0) on protonation. The Stark-derived beta(0) values are generally larger for related {Ru(II)(NH(3))(5)}(2+) complexes than for their {Fe(II)(CN)(5)}(3)(-) analogues, consistent with the HRS data in water. However, the HRS data in methanol show that the stronger solvatochromism of the Fe(II) complexes causes their NLO responses to surpass those of their Ru(II) counterparts upon changing the solvent medium.

Tunable Rh 2(II,II) Light Absorbers as Excited State Electron Donors and Acceptors Accessible with Red/Near-IR Irradiation

DOE PAGES

Whittemore, Tyler; Millet, Agustin; Sayre, Hannah; ...

2018-04-04

In this study, a series of dirhodium(II,II) paddlewheeel complexes of the type cis-[Rh 2(μ-DTolF) 2(μ-L) 2][BF 4] 2, where DTolF = N,N'-di(p-tolyl)formamidinate and L = 1,8-naphthyridine (np), 2-(pyridin-2-yl)-1,8-naphthyridine (pynp), 2-(quinolin-2-yl)-1,8-naphthyridine (qnnp), and 2-(1,8-naphthyridin-2-yl)quinoxaline (qxnp), were synthesized and characterized. These molecules feature new tridentate ligands that concomitantly bridge the dirhodium core and cap the axial positions. The complexes absorb light strongly throughout the ultraviolet/visible range and into the near-infrared region and exhibit relatively long-lived triplet excited-state lifetimes. Both the singlet and triplet excited states exhibit metal/ligand-to-ligand charge transfer (ML-LCT) in nature as determined by transient absorption spectroscopy and spectroelectrochemistry measurements. Whenmore » irradiated with low-energy light, these black dyes are capable of undergoing reversible bimolecular electron transfer both to the electron acceptor methyl viologen and from the electron donor p-phenylenediamine. Photoinduced charge transfer in the latter was inaccessible with previous Rh 2(II,II) complexes. Finally, these results underscore the fact that the excited state of this class of molecules can be readily tuned for electron-transfer reactions upon simple synthetic modification and highlight their potential as excellent candidates for p- and n-type semiconductor applications and for improved harvesting of low-energy light to drive useful photochemical reactions.« less

Tunable Rh 2(II,II) Light Absorbers as Excited State Electron Donors and Acceptors Accessible with Red/Near-IR Irradiation

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

Whittemore, Tyler; Millet, Agustin; Sayre, Hannah

In this study, a series of dirhodium(II,II) paddlewheeel complexes of the type cis-[Rh 2(μ-DTolF) 2(μ-L) 2][BF 4] 2, where DTolF = N,N'-di(p-tolyl)formamidinate and L = 1,8-naphthyridine (np), 2-(pyridin-2-yl)-1,8-naphthyridine (pynp), 2-(quinolin-2-yl)-1,8-naphthyridine (qnnp), and 2-(1,8-naphthyridin-2-yl)quinoxaline (qxnp), were synthesized and characterized. These molecules feature new tridentate ligands that concomitantly bridge the dirhodium core and cap the axial positions. The complexes absorb light strongly throughout the ultraviolet/visible range and into the near-infrared region and exhibit relatively long-lived triplet excited-state lifetimes. Both the singlet and triplet excited states exhibit metal/ligand-to-ligand charge transfer (ML-LCT) in nature as determined by transient absorption spectroscopy and spectroelectrochemistry measurements. Whenmore » irradiated with low-energy light, these black dyes are capable of undergoing reversible bimolecular electron transfer both to the electron acceptor methyl viologen and from the electron donor p-phenylenediamine. Photoinduced charge transfer in the latter was inaccessible with previous Rh 2(II,II) complexes. Finally, these results underscore the fact that the excited state of this class of molecules can be readily tuned for electron-transfer reactions upon simple synthetic modification and highlight their potential as excellent candidates for p- and n-type semiconductor applications and for improved harvesting of low-energy light to drive useful photochemical reactions.« less

Gas phase reactions of doubly charged alkaline earth and transition metal(II)-ligand complexes generated by electrospray ionization

NASA Astrophysics Data System (ADS)

Kohler, Martin; Leary, Julie A.

1997-03-01

Doubly charged metal(II)-complexes of [alpha] 1-3, [alpha] 1-6 mannotriose and the conserved trimannosyl core pentasaccharide as well as doubly charged complexes of Co(II), Mn(II), Ca(II) and Sr(II) with acetonitrile generated by electrospray ionization were studied by low energy collision induced dissociation (CID). Two main fragmentation pathways were observed for the metal(II)-oligosaccharide complexes. Regardless of the coordinating metal, loss of a neutral dehydrohexose residue (162 Da) from the doubly charged precursor ion is observed, forming a doubly charged product ion. However, if the oligosaccharide is coordinated to Co(II) or Mn(II), loss of a dehydroxyhexose cation is also observed. Investigation of the low mass region of the mass spectra of the metal coordinated oligosaccharides revealed intense signals corresponding to [metal(II) + (CH3CN)n2+ (where n = 1-6) species which were being formed by the metal(II) ions and the acetonitrile present in the sample. Analysis of these metal(II)-acetonitrile complexes provided further insight into the processes occurring upon low energy CID of doubly charged metal complexes. The metal(II)-acetonitrile system showed neutral loss and ligand cleavage as observed with the oligosaccharide complexes, as well as a series of six different dissociation mechanisms, most notable among them reduction from [metal(II) + (CH3CN)n2+ to the bare [metal(I)]+ species by electron transfer. Depending on the metal and collision gas chosen, one observes electron transfer from the ligand to the metal, electron transfer from the collision gas to the metal, proton transfer between ligands, heterolytic cleavage of the ligands, reactive collisions and loss of neutral ligands.

Reversible double oxidation and protonation of the non-innocent bridge in a nickel(II) salophen complex.

PubMed

de Bellefeuille, David; Askari, Mohammad S; Lassalle-Kaiser, Benedikt; Journaux, Yves; Aukauloo, Ally; Orio, Maylis; Thomas, Fabrice; Ottenwaelder, Xavier

2012-12-03

Substitution on the aromatic bridge of a nickel(II) salophen complex with electron-donating dimethylamino substituents creates a ligand with three stable, easily and reversibly accessible oxidation states. The one-electron-oxidized product is characterized as a nickel(II) radical complex with the radical bore by the central substituted aromatic ring, in contrast to other nickel(II) salen or salophen complexes that oxidize on the phenolate moieties. The doubly oxidized product, a singlet species, is best described as having an iminobenzoquinone bridge with a vinylogous distribution of bond lengths between the dimethylamino substituents. Protonation of the dimethylamino substituents inhibits these redox processes on the time scale of cyclovoltammetry, but electrolysis and chemical oxidation are consistent with deprotonation occurring concomitantly with electron transfer to yield the mono- and dioxidized species described above.

Effect of amino acids on the interaction between cobalamin(II) and dehydroascorbic acid

NASA Astrophysics Data System (ADS)

Dereven'kov, I. A.; Thi, Thu Thuy Bui; Salnikov, D. S.; Makarov, S. V.

2016-03-01

The kinetics of the reaction between one-electron-reduced cobalamin (cobalamin(II), Cb(II)) and the two-electron-oxidized form of vitamin C (dehydroascorbic acid, DHA) with amino acids in an acidic medium is studied by conventional UV-Vis spectroscopy. It is shown that the oxidation of Cbl(II) by dehydroascorbic acid proceeds only in the presence of sulfur-containing amino acids (cysteine, acetylcysteine). A proposed reaction mechanism includes the step of amino acid coordination on the Co(II)-center through the sulfur atom, along with that of the interaction between this complex and DHA molecules, which results in the formation of ascorbyl radical and the corresponding Co(III) thiolate complex.

Spectroscopic Investigations of Catalase Compound II: Characterization of an Iron(IV) Hydroxide Intermediate in a Non-thiolate-Ligated Heme Enzyme

PubMed Central

Yosca, Timothy H.; Langston, Matthew C.; Krest, Courtney M.; Onderko, Elizabeth L.; Grove, Tyler L.; Livada, Jovan; Green, Michael T.

2018-01-01

We report on the protonation state of Helicobacter pylori catalase compound II. UV/visible, Mössbauer, and X-ray absorption spectroscopies have been used to examine the intermediate from pH 5 to 14. We have determined that HPC-II exists in an iron(IV) hydroxide state up to pH 11. Above this pH, the iron(IV) hydroxide complex transitions to a new species (pKa = 13.1) with Mössbauer parameters that are indicative of an iron(IV)-oxo intermediate. Recently, we discussed a role for an elevated compound II pKa in diminishing the compound I reduction potential. This has the effect of shifting the thermodynamic landscape toward the two-electron chemistry that is critical for catalase function. In catalase, a diminished potential would increase the selectivity for peroxide disproportionation over off-pathway one-electron chemistry, reducing the buildup of the inactive compound II state and reducing the need for energetically expensive electron donor molecules. PMID:27960340

10 CFR Appendix II to Part 960 - NRC and EPA Requirements for Preclosure Repository Performance

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 4 2010-01-01 2010-01-01 false NRC and EPA Requirements for Preclosure Repository... SCREENING OF POTENTIAL SITES FOR A NUCLEAR WASTE REPOSITORY Pt. 960, App. II Appendix II to Part 960—NRC and EPA Requirements for Preclosure Repository Performance Under proposed 40 CFR part 191, subpart A...

A Dynamic Model of the Initial Spares Support List Development Process

DTIC Science & Technology

1979-06-01

S117Z1NOTE NREI -NOT READI END ITERS IIT7INOTE GPEI -QUANTITY OF PARTS M. END ITER 11775NOTE FUSERF -PARTS USE RATE FACTOR U8WOTE OP U -OTHER PARTS USE...FAILURES ’I 1675R PtJER.L=(NREI.K) (QPEI) (PUSERF.K)+OPUR II7HNOTE PUSER -PARTS USE RATE II7t5NOTE NREI -NOT READY END ITEMS II756NOTE GPEI -QUANTITY

46 CFR Appendix II to Part 153 - Metric Units Used in Part 153

Code of Federal Regulations, 2013 CFR

2013-10-01

.../cm2. ......do kPa 1×10 3 N/m 2. Temperature Degree Celsius °C 5/9 (°F-32). Viscosity milli-Pascal... 46 Shipping 5 2013-10-01 2013-10-01 false Metric Units Used in Part 153 II Appendix II to Part 153... common metric Force Newton N 0.225 lbs. Length Meter m 39.37 in. Centimeter cm .3937 in. Pressure Pascal...

46 CFR Appendix II to Part 153 - Metric Units Used in Part 153

Code of Federal Regulations, 2012 CFR

2012-10-01

.../cm2. ......do kPa 1×10 3 N/m 2. Temperature Degree Celsius °C 5/9 (°F-32). Viscosity milli-Pascal... 46 Shipping 5 2012-10-01 2012-10-01 false Metric Units Used in Part 153 II Appendix II to Part 153... common metric Force Newton N 0.225 lbs. Length Meter m 39.37 in. Centimeter cm .3937 in. Pressure Pascal...

46 CFR Appendix II to Part 153 - Metric Units Used in Part 153

Code of Federal Regulations, 2014 CFR

2014-10-01

.../cm2. ......do kPa 1×10 3 N/m 2. Temperature Degree Celsius °C 5/9 (°F-32). Viscosity milli-Pascal... 46 Shipping 5 2014-10-01 2014-10-01 false Metric Units Used in Part 153 II Appendix II to Part 153... common metric Force Newton N 0.225 lbs. Length Meter m 39.37 in. Centimeter cm .3937 in. Pressure Pascal...

The green hemoproteins of bovine erythrocytes. II. Spectral, ligand-binding, and electrochemical properties.

PubMed

DeFilippi, L J; Hultquist, D E

1978-05-10

The two green hemoproteins isolated from bovine erythrocytes (form I and form II) have been characterized as to spectral, electrochemical, and chemical properties. The absorption spectra of the isolated hemoproteins are typical of high spin ferric states. Reduction of the hemoproteins yields high spin ferrohemoproteins. Complexation of the ferrohemoproteins with CO and the ferrihemoproteins with cyanide yields low spin complexes, demonstrating the presence of an exchangeable weak field ligand in both the ferrous and ferric states of the hemoproteins. The differences in position and intensity of the absorption peaks of the visible spectra allow the two forms to be distinguished from one another. The midpoint potential of forms I and II were found to be +0.075 and +0.019 V, respectively, at pH 6.4 and +0.038 and -0.005 V, respectively, at pH 7.0. This is consistent with the gaining of 1 proton/electron during the reduction. The Nernst plot reveals an unusual 0.5-electron transfer, whereas a quantitative titration demonstrates a 1-electron transfer. Form I binds cyanide more tightly than form II (KD of 84 and 252 micrometer, respectively). The observed spectral, electrochemical, and ligand-binding differences between forms I and II can be explained in terms of a greater electron-withdrawing ability of the side chains of the heme of form I relative to the heme of form II.

Searching for New Physics with Top Quarks and Upgrade to the Muon Spectrometer at ATLAS

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

Schwarz, Thomas Andrew

2015-06-29

Over the funding period of this award, my research has focused on searching for new physics with top quarks and in the Higgs sector. The highly energetic top quark events at the LHC are an excellent venue to search for new physics, as well as make standard model measurements. Further, the recent discovery of the Higgs boson motivates searching for new physics that could be associated with it. This one-year award has facilitated the beginning of my research program, which has resulted in four publications, several conference talks, and multiple leadership positions within physics groups. Additionally, we are contributing tomore » ATLAS upgrades and operations. As part of the Phase I upgrade, I have taken on the responsibility of the design, prototyping, and quality control of a signal packet router for the trigger electronics of the New Small Wheel. This is a critical component of the upgrade, as the router is the main switchboard for all trigger signals to track finding processors. I am also leading the Phase II upgrade of the readout electronics of the muon spectrometer, and have been selected as the USATLAS Level-2 manager of the Phase II upgrade of the muon spectrometer. The award has been critical in these contributions to the experiment.« less

Mn(II) Oxidation by the Multicopper Oxidase Complex Mnx: A Coordinated Two-Stage Mn(II)/(III) and Mn(III)/(IV) Mechanism.

PubMed

Soldatova, Alexandra V; Romano, Christine A; Tao, Lizhi; Stich, Troy A; Casey, William H; Britt, R David; Tebo, Bradley M; Spiro, Thomas G

2017-08-23

The bacterial manganese oxidase MnxG of the Mnx protein complex is unique among multicopper oxidases (MCOs) in carrying out a two-electron metal oxidation, converting Mn(II) to MnO 2 nanoparticles. The reaction occurs in two stages: Mn(II) → Mn(III) and Mn(III) → MnO 2 . In a companion study , we show that the electron transfer from Mn(II) to the low-potential type 1 Cu of MnxG requires an activation step, likely forming a hydroxide bridge at a dinuclear Mn(II) site. Here we study the second oxidation step, using pyrophosphate (PP) as a Mn(III) trap. PP chelates Mn(III) produced by the enzyme and subsequently allows it to become a substrate for the second stage of the reaction. EPR spectroscopy confirms the presence of Mn(III) bound to the enzyme. The Mn(III) oxidation step does not involve direct electron transfer to the enzyme from Mn(III), which is shown by kinetic measurements to be excluded from the Mn(II) binding site. Instead, Mn(III) is proposed to disproportionate at an adjacent polynuclear site, thereby allowing indirect oxidation to Mn(IV) and recycling of Mn(II). PP plays a multifaceted role, slowing the reaction by complexing both Mn(II) and Mn(III) in solution, and also inhibiting catalysis, likely through binding at or near the active site. An overall mechanism for Mnx-catalyzed MnO 2 production from Mn(II) is presented.

78 FR 9057 - Medicare Program; Request for Information on the Use of Clinical Quality Measures (CQMs) Reported...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-02-07

... Part II: Lifelong Learning and Self-Assessment Part III: Cognitive Expertise Part IV: Practice...: Licensure and Professional Standing Part II: Lifelong Learning and Self-Assessment Part III: Cognitive...\\ The MOC assesses physicians' commitment to lifelong learning according to the following six core...

Optical and Electronic NOx Sensors for Applications in Mechatronics

PubMed Central

Di Franco, Cinzia; Elia, Angela; Spagnolo, Vincenzo; Scamarcio, Gaetano; Lugarà, Pietro Mario; Ieva, Eliana; Cioffi, Nicola; Torsi, Luisa; Bruno, Giovanni; Losurdo, Maria; Garcia, Michael A.; Wolter, Scott D.; Brown, April; Ricco, Mario

2009-01-01

Current production and emerging NOx sensors based on optical and nanomaterials technologies are reviewed. In view of their potential applications in mechatronics, we compared the performance of: i) Quantum cascade lasers (QCL) based photoacoustic (PA) systems; ii) gold nanoparticles as catalytically active materials in field-effect transistor (FET) sensors, and iii) functionalized III-V semiconductor based devices. QCL-based PA sensors for NOx show a detection limit in the sub part-per-million range and are characterized by high selectivity and compact set-up. Electrochemically synthesized gold-nanoparticle FET sensors are able to monitor NOx in a concentration range from 50 to 200 parts per million and are suitable for miniaturization. Porphyrin-functionalized III-V semiconductor materials can be used for the fabrication of a reliable NOx sensor platform characterized by high conductivity, corrosion resistance, and strong surface state coupling. PMID:22412315

NASA Electrical, Electronic and Electromechanical (EEE) Parts Assurance, An Overview

NASA Technical Reports Server (NTRS)

Label, Kenneth A.; Sampson, Michael J.

2017-01-01

This presentation will cover NASA Electrical, Electronic and Electromechanical (EEE) Parts Assurance Structure, NASA Electronic Parts and Packaging (NEPP) Program, NASA Electronic Parts Assurance Group (NEPAG), examples of assurance challenges, and future challenges.

Coprecipitation of gold(III) complex ions with manganese(II) hydroxide and their stoichiometric reduction to atomic gold (Au(0)): analysis by Mössbauer spectroscopy and XPS.

PubMed

Yamashita, Mamiko; Ohashi, Hironori; Kobayashi, Yasuhiro; Okaue, Yoshihiro; Kurisaki, Tsutomu; Wakita, Hisanobu; Yokoyama, Takushi

2008-03-01

To elucidate the formation process of precursor of gold-supported manganese dioxide (MnO2), the coprecipitation behavior of [AuCl4-n(OH)n](-) (n=0-4) (Au(III)) complex ions with manganese(II) hydroxide (Mn(OH)2 and the change in their chemical state were examined. The Au(III) complex ions were rapidly and effectively coprecipitated with Mn(OH)(2) at pH 9. According to the Mössbauer spectra for gold (Au) coprecipitated with Mn(OH)2, below an Au content of 60 wt% in the coprecipitates, all of the coprecipitated Au existed in the atomic state (Au(0)), while, above an Au content of 65 wt%, part of the gold existed in the Au(III) state, and the proportion increased with increasing coprecipitated Au content. Based on the results of X-ray photoelectron spectroscopy, Mn(II) in Mn(OH)2 converted to Mn(IV) in conjunction with coprecipitation of Au(III) complex ions. These results indicate that the rapid stoichiometric reduction of Au(III) to Au(0) is caused by electron transfer from Mn(II) in Mn(OH)2 to the Au(III) complex ion through an Mn-O-Au bond.

SHEFEX II - Aerodynamic Re-Entry Controlled Sharp Edge Flight Experiment

NASA Astrophysics Data System (ADS)

Longo, J. M. A.; Turner, J.; Weihs, H.

2009-01-01

In this paper the basic goals and architecture of the SHEFEX II mission is presented. Also launched by a two staged sounding rocket system SHEFEX II is a consequent next step in technology test and demonstration. Considering all experience and collected flight data obtained during the SHEFEX I Mission, the test vehicle has been re-designed and extended by an active control system, which allows active aerodynamic control during the re-entry phase. Thus, ceramic based aerodynamic control elements like rudders, ailerons and flaps, mechanical actuators and an automatic electronic control unit has been implemented. Special focus is taken on improved GNC Elements. In addition, some other experiments including an actively cooled thermal protection element, advanced sensor equipment, high temperature antenna inserts etc. are part of the SHEFEX II experimental payload. A final 2 stage configuration has been selected considering Brazilian solid rocket boosters derived from the S 40 family. During the experiment phase a maximum entry velocity of Mach around 10 is expected for 50 seconds. Considering these flight conditions, the heat loads are not representative for a RLV re-entry, however, it allows to investigate the principal behaviour of such a facetted ceramic TPS, a sharp leading edge at the canards and fins and all associated gas flow effects and their structural response.

40 CFR Appendix II to Part 86 - Temperature Schedules

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 19 2010-07-01 2010-07-01 false Temperature Schedules II Appendix II... Appendix II to Part 86—Temperature Schedules (a) Ambient temperature cycle for the diurnal emission portion of the evaporative emission test (see § 86.133). Table I—Temperature Versus Time Sequence Use linear...

40 CFR Appendix II to Part 86 - Temperature Schedules

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 20 2013-07-01 2013-07-01 false Temperature Schedules II Appendix II... Appendix II to Part 86—Temperature Schedules (a) Ambient temperature cycle for the diurnal emission portion of the evaporative emission test (see § 86.133). Table I—Temperature Versus Time Sequence Use linear...

40 CFR Appendix II to Part 86 - Temperature Schedules

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 19 2011-07-01 2011-07-01 false Temperature Schedules II Appendix II... Appendix II to Part 86—Temperature Schedules (a) Ambient temperature cycle for the diurnal emission portion of the evaporative emission test (see § 86.133). Table I—Temperature Versus Time Sequence Use linear...

40 CFR Appendix II to Part 86 - Temperature Schedules

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 20 2012-07-01 2012-07-01 false Temperature Schedules II Appendix II... Appendix II to Part 86—Temperature Schedules (a) Ambient temperature cycle for the diurnal emission portion of the evaporative emission test (see § 86.133). Table I—Temperature Versus Time Sequence Use linear...

Gunshot residue testing in suicides: Part II: Analysis by inductive coupled plasma-atomic emission spectrometry.

PubMed

Molina, D Kimberley; Castorena, Joe L; Martinez, Michael; Garcia, James; DiMaio, Vincent J M

2007-09-01

Several different methods can be employed to test for gunshot residue (GSR) on a decedent's hands, including scanning electron microscopy with energy dispersive x-ray (SEM/EDX) and inductive coupled plasma-atomic emission spectrometry (ICP-AES). In part I of this 2-part series, GSR results performed by SEM/EDX in undisputed cases of suicidal handgun wounds were studied. In part II, the same population was studied, deceased persons with undisputed suicidal handgun wounds, but GSR testing was performed using ICP-AES. A total of 102 cases were studied and analyzed for caliber of weapon, proximity of wound, and the results of the GSR testing. This study found that 50% of cases where the deceased was known to have fired a handgun immediately prior to death had positive GSR results by ICP/AES, which did not differ from the results of GSR testing by SEM/EDX. Since only 50% of cases where the person is known to have fired a weapon were positive for GSR by either method, this test should not be relied upon to determine whether someone has discharged a firearm and is not useful as a determining factor of whether or not a wound is self-inflicted or non-self-inflicted. While a positive GSR result may be of use, a negative result is not helpful in the medical examiner setting as a negative result indicates that either a person fired a weapon prior to death or a person did not fire a weapon prior to death.

Ambient Mechanochemical Solid-State Reactions of Carbon Nanotubes and Their Reactions via Covalent Coordinate Bond in Solution

NASA Astrophysics Data System (ADS)

Kabbani, Mohamad A.

In its first part, this thesis deals with ambient mechanochemical solid-state reactions of differently functionalized multiple walled carbon nanotubes (MWCNTs) while in its second part it investigates the cross-linking reactions of CNTs in solution via covalent coordinate bonds with transitions metals and carboxylate groups decorating their surfaces. In the first part a series of mechanochemical reactions involving different reactive functionalities on the CNTs such as COOH/OH, COOH/NH2 and COCl/OH were performed. The solid-state unzipping of CNTs leading to graphene formation was confirmed using spectroscopic, thermal and electron microscopy techniques. The non-grapheme products were established using in-situ quadruple mass spectroscopy. The experimental results were confirmed by theoretical simulation calculations using the 'hot spots' protocol. The kinetics of the reaction between MWCNT-COOH and MWCNT-OH was monitored using variable temperature Raman spectroscopy. The low activation energy was discussed in terms of hydrogen bond mediated proton transfer mechanism. The second part involves the reaction of MWCNTII COOH with Zn (II) and Cu (II) to form CNT metal-organic frame (MOFs) products that were tested for their effective use as counter-electrodes in dyes sensitized solar cells (DSSC). The thesis concludes by the study of the room temperature reaction between the functionalized graphenes, GOH and G'-COOH followed by the application of compressive loads. The 3D solid graphene pellet product ( 0.6gm/cc) is conductive and reflective with a 35MPa ultimate strength as compared to 10MPa strength of graphite electrode ( 2.2gm/cc).

Electron transfer flavoprotein domain II orientation monitored using double electron-electron resonance between an enzymatically reduced, native FAD cofactor, and spin labels.

PubMed

Swanson, Michael A; Kathirvelu, Velavan; Majtan, Tomas; Frerman, Frank E; Eaton, Gareth R; Eaton, Sandra S

2011-03-01

Human electron transfer flavoprotein (ETF) is a soluble mitochondrial heterodimeric flavoprotein that links fatty acid β-oxidation to the main respiratory chain. The crystal structure of human ETF bound to medium chain acyl-CoA dehydrogenase indicates that the flavin adenine dinucleotide (FAD) domain (αII) is mobile, which permits more rapid electron transfer with donors and acceptors by providing closer access to the flavin and allows ETF to accept electrons from at least 10 different flavoprotein dehydrogenases. Sequence homology is high and low-angle X-ray scattering is identical for Paracoccus denitrificans (P. denitrificans) and human ETF. To characterize the orientations of the αII domain of P. denitrificans ETF, distances between enzymatically reduced FAD and spin labels in the three structural domains were measured by double electron-electron resonance (DEER) at X- and Q-bands. An FAD to spin label distance of 2.8 ± 0.15 nm for the label in the FAD-containing αII domain (A210C) agreed with estimates from the crystal structure (3.0 nm), molecular dynamics simulations (2.7 nm), and rotamer library analysis (2.8 nm). Distances between the reduced FAD and labels in αI (A43C) were between 4.0 and 4.5 ± 0.35 nm and for βIII (A111C) the distance was 4.3 ± 0.15 nm. These values were intermediate between estimates from the crystal structure of P. denitrificans ETF and a homology model based on substrate-bound human ETF. These distances suggest that the αII domain adopts orientations in solution that are intermediate between those which are observed in the crystal structures of free ETF (closed) and ETF bound to a dehydrogenase (open). Copyright © 2011 The Protein Society.

Photodynamic research at Baylor University Medical Center Dallas, Texas

NASA Astrophysics Data System (ADS)

Gulliya, Kirpal S.; Matthews, James Lester; Sogandares-Bernal, Franklin M.; Aronoff, Billie L.; Judy, Millard M.

1993-03-01

We received our first CO2 laser at Baylor University Medical Center in December 1974, following a trip to Israel in January of that year. Discussion with the customs office of the propriety of charging an 18% import tax lasted for nine months. We lost that argument. Baylor has been using lasers of many types for many procedures since that time. About ten years ago, through the kindness of Tom Dougherty and Roswell Park, we started working with photodynamic therapy, first with hematoporphyrin I and later with dihematoporphyrin ether (II). In February 1984, we were invited to a conference at Los Alamos, New Mexico, U.S.A. on medical applications of the free electron laser as part of the Star Wars Program. A grant application from Baylor was approved that November, but funding did not start for many months. This funding contributed to the development of a new research center as part of Baylor Research Institute. Many of the projects investigated at Baylor dealt with applications of the free electron laser (FEL), after it became available. A staff was assembled and many projects are still ongoing. I would like to outline those which are in some way related to photodynamic therapy.

Electron impact excitation of argon in the extreme vacuum ultraviolet

NASA Technical Reports Server (NTRS)

Mentall, J. E.; Morgan, H. D.

1976-01-01

Polarization-free excitation cross sections in the extreme vacuum ultraviolet have been measured for electron impact on Ar. Observed spectral features were those lines of Ar I and Ar II which lie between 700 and 1100 A. Excitation functions were measured for the Ar I resonance line at 1048 A and the Ar II resonance line at 920 A. Peak cross sections for these two lines were found to be (39.4 plus or minus 7.9) x 10 to the -18th and (6.9 plus or minus 1.4) x 10 to the -18th, respectively. At low energies, excitation of the Ar II resonance line is dominated by an electron exchange transition.

17 CFR 405.2 - Reports to be made by registered government securities brokers and dealers.

Code of Federal Regulations, 2010 CFR

2010-04-01

... government securities broker or dealer shall file Part I of Form BD-Y2K (§ 249.618 of this title) prepared as..., shall file Part II of Form BD-Y2K (§ 249.618 of this title). Part II of Form BD-Y2K shall address each... registered government securities broker or dealer that was not required to file Part II of Form BD-Y2K under...

Basic Services for Children: A Continuing Search for Learning Priorities. A Dossier for Initiating a Dialogue--Part II, 1978. Experiments and Innovations in Education No. 37.

ERIC Educational Resources Information Center

United Nations Educational, Scientific, and Cultural Organization, Paris (France).

Both parts I and II of the dossier are collections of selected activities directed toward the deprived young in a developing world. This book, part II, departs from its predecessor in that it takes a more global view of education services to both children and adults in developing countries. Part A discusses the philosophy and scope of the dossier.…

Electronic structure and reactivity of three-coordinate iron complexes.

PubMed

Holland, Patrick L

2008-08-01

[Reaction: see text]. The identity and oxidation state of the metal in a coordination compound are typically thought to be the most important determinants of its reactivity. However, the coordination number (the number of bonds to the metal) can be equally influential. This Account describes iron complexes with a coordination number of only three, which differ greatly from iron complexes with octahedral (six-coordinate) geometries with respect to their magnetism, electronic structure, preference for ligands, and reactivity. Three-coordinate complexes with a trigonal-planar geometry are accessible using bulky, anionic, bidentate ligands (beta-diketiminates) that steer a monodentate ligand into the plane of their two nitrogen donors. This strategy has led to a variety of three-coordinate iron complexes in which iron is in the +1, +2, and +3 oxidation states. Systematic studies on the electronic structures of these complexes have been useful in interpreting their properties. The iron ions are generally high spin, with singly occupied orbitals available for pi interactions with ligands. Trends in sigma-bonding show that iron(II) complexes favor electronegative ligands (O, N donors) over electropositive ligands (hydride). The combination of electrostatic sigma-bonding and the availability of pi-interactions stabilizes iron(II) fluoride and oxo complexes. The same factors destabilize iron(II) hydride complexes, which are reactive enough to add the hydrogen atom to unsaturated organic molecules and to take part in radical reactions. Iron(I) complexes use strong pi-backbonding to transfer charge from iron into coordinated alkynes and N 2, whereas iron(III) accepts charge from a pi-donating imido ligand. Though the imidoiron(III) complex is stabilized by pi-bonding in the trigonal-planar geometry, addition of pyridine as a fourth donor weakens the pi-bonding, which enables abstraction of H atoms from hydrocarbons. The unusual bonding and reactivity patterns of three-coordinate iron compounds may lead to new catalysts for oxidation and reduction reactions and may be used by nature in transient intermediates of nitrogenase enzymes.

Emergence of californium as the second transitional element in the actinide series

PubMed Central

Cary, Samantha K.; Vasiliu, Monica; Baumbach, Ryan E.; Stritzinger, Jared T.; Green, Thomas D.; Diefenbach, Kariem; Cross, Justin N.; Knappenberger, Kenneth L.; Liu, Guokui; Silver, Mark A.; DePrince, A. Eugene; Polinski, Matthew J.; Van Cleve, Shelley M.; House, Jane H.; Kikugawa, Naoki; Gallagher, Andrew; Arico, Alexandra A.; Dixon, David A.; Albrecht-Schmitt, Thomas E.

2015-01-01

A break in periodicity occurs in the actinide series between plutonium and americium as the result of the localization of 5f electrons. The subsequent chemistry of later actinides is thought to closely parallel lanthanides in that bonding is expected to be ionic and complexation should not substantially alter the electronic structure of the metal ions. Here we demonstrate that ligation of californium(III) by a pyridine derivative results in significant deviations in the properties of the resultant complex with respect to that predicted for the free ion. We expand on this by characterizing the americium and curium analogues for comparison, and show that these pronounced effects result from a second transition in periodicity in the actinide series that occurs, in part, because of the stabilization of the divalent oxidation state. The metastability of californium(II) is responsible for many of the unusual properties of californium including the green photoluminescence. PMID:25880116

Measuring and interpreting X-ray fluorescence from planetary surfaces.

PubMed

Owens, Alan; Beckhoff, Burkhard; Fraser, George; Kolbe, Michael; Krumrey, Michael; Mantero, Alfonso; Mantler, Michael; Peacock, Anthony; Pia, Maria-Grazia; Pullan, Derek; Schneider, Uwe G; Ulm, Gerhard

2008-11-15

As part of a comprehensive study of X-ray emission from planetary surfaces and in particular the planet Mercury, we have measured fluorescent radiation from a number of planetary analog rock samples using monochromatized synchrotron radiation provided by the BESSY II electron storage ring. The experiments were carried out using a purpose built X-ray fluorescence (XRF) spectrometer chamber developed by the Physikalisch-Technische Bundesanstalt, Germany's national metrology institute. The XRF instrumentation is absolutely calibrated and allows for reference-free quantitation of rock sample composition, taking into account secondary photon- and electron-induced enhancement effects. The fluorescence data, in turn, have been used to validate a planetary fluorescence simulation tool based on the GEANT4 transport code. This simulation can be used as a mission analysis tool to predict the time-dependent orbital XRF spectral distributions from planetary surfaces throughout the mapping phase.

Thermal analysis, X-ray powder diffraction and electron microscopy data related with the production of 1:1 Caffeine:Glutaric Acid cocrystals.

PubMed

Duarte, Íris; Andrade, Rita; Pinto, João F; Temtem, Márcio

2016-09-01

The data presented in this article are related to the production of 1:1 Caffeine:Glutaric Acid cocrystals as part of the research article entitled "Green production of cocrystals using a new solvent-free approach by spray congealing" (Duarte et al., 2016) [1]. More specifically, here we present the thermal analysis and the X-ray powder diffraction data for pure Glutaric Acid, used as a raw material in [1]. We also include the X-ray powder diffraction and electron microscopy data obtained for the 1:1 Caffeine:Glutaric Acid cocrystal (form II) produced using the cooling crystallization method reported in "Operating Regions in Cooling Cocrystallization of Caffeine and Glutaric Acid in Acetonitrile" (Yu et al., 2010) [2]. Lastly, we show the X-ray powder diffraction data obtained for assessing the purity of the 1:1 Caffeine:Glutaric cocrystals produced in [1].

Inter-ring rotations of AAA ATPase p97 revealed by electron cryomicroscopy

PubMed Central

Yeung, Heidi O.; Förster, Andreas; Bebeacua, Cecilia; Niwa, Hajime; Ewens, Caroline; McKeown, Ciarán; Zhang, Xiaodong; Freemont, Paul S.

2014-01-01

The type II AAA+ protein p97 is involved in numerous cellular activities, including endoplasmic reticulum-associated degradation, transcription activation, membrane fusion and cell-cycle control. These activities are at least in part regulated by the ubiquitin system, in which p97 is thought to target ubiquitylated protein substrates within macromolecular complexes and assist in their extraction or disassembly. Although ATPase activity is essential for p97 function, little is known about how ATP binding or hydrolysis is coupled with p97 conformational changes and substrate remodelling. Here, we have used single-particle electron cryomicroscopy (cryo-EM) to study the effect of nucleotides on p97 conformation. We have identified conformational heterogeneity within the cryo-EM datasets from which we have resolved two major p97 conformations. A comparison of conformations reveals inter-ring rotations upon nucleotide binding and hydrolysis that may be linked to the remodelling of target protein complexes. PMID:24598262

Removal combined with reduction of hexavalent chromium from aqueous solution by Fe-ethylene glycol complex microspheres

NASA Astrophysics Data System (ADS)

Zhang, Yong-Xing; Jia, Yong

2016-12-01

Three-dimensional Fe-ethylene glycol (Fe-EG) complex microspheres were synthesized by a facile hydrothermal method, and were characterized by field emission scanning electron microscopy and transmission electron microscopy. The adsorption as well as reduction properties of the obtained Fe-EG complex microspheres towards Cr(VI) ions were studied. The experiment data of adsorption kinetic and isotherm were fitted by nonlinear regression approach. In neutral condition, the maximum adsorption capacity was 49.78 mg g-1 at room temperature, and was increased with the increasing of temperature. Thermodynamic parameters including the Gibbs free energy, standard enthalpy and standard entropy revealed that adsorption of Cr(VI) was a feasible, spontaneous and endothermic process. Spectroscopic analysis revealed the adsorption of Cr(VI) was a physical adsorption process. The adsorbed CrO42- ions were partly reduced to Cr(OH)3 by Fe(II) ions and the organic groups in the Fe-EG complex.

Herschel Galactic Plane Survey of [NII] Fine Structure Emission

NASA Astrophysics Data System (ADS)

Goldsmith, Paul F.; Yıldız, Umut A.; Langer, William D.; Pineda, Jorge L.

2015-12-01

We present the first large-scale high angular resolution survey of ionized nitrogen in the Galactic Plane through emission of its two fine structure transitions ([N ii]) at 122 and 205 μm. The observations were largely obtained with the PACS instrument onboard the Herschel Space Observatory. The lines of sight were in the Galactic plane, following those of the Herschel OTKP project GOT C+. Both lines are reliably detected at the 10-8-10-7 Wm-2 sr-1 level over the range -60° ≤ l ≤ 60°. The rms of the intensity among the 25 PACS spaxels of a given pointing is typically less than one third of the mean intensity, showing that the emission is extended. [N ii] is produced in gas in which hydrogen is ionized, and collisional excitation is by electrons. The ratio of the two fine structure transitions provides a direct measurement of the electron density, yielding n(e) largely in the range 10-50 cm-3 with an average value of 29 cm-3 and N+ column densities 1016-1017 cm-2. [N ii] emission is highly correlated with that of [C ii], and we calculate that between 1/3 and 1/2 of the [C ii] emission is associated with the ionized gas. The relatively high electron densities indicate that the source of the [N ii] emission is not the warm ionized medium (WIM), which has electron densities more than 100 times smaller. Possible origins of the observed [N ii] include the ionized surfaces of dense atomic and molecular clouds, the extended low-density envelopes of H ii regions, and low-filling factor high-density fluctuations of the WIM.

Electron-cyclotron absorption in high-temperature plasmas: quasi-exact analytical evaluation and comparative numerical analysis

NASA Astrophysics Data System (ADS)

Albajar, F.; Bertelli, N.; Bornatici, M.; Engelmann, F.

2007-01-01

On the basis of the electromagnetic energy balance equation, a quasi-exact analytical evaluation of the electron-cyclotron (EC) absorption coefficient is performed for arbitrary propagation (with respect to the magnetic field) in a (Maxwellian) magneto-plasma for the temperature range of interest for fusion reactors (in which EC radiation losses tend to be important in the plasma power balance). The calculation makes use of Bateman's expansion for the product of two Bessel functions, retaining the lowest-order contribution. The integration over electron momentum can then be carried out analytically, fully accounting for finite Larmor radius effects in this approximation. On the basis of the analytical expressions for the EC absorption coefficients of both the extraordinary and ordinary modes thus obtained, (i) for the case of perpendicular propagation simple formulae are derived for both modes and (ii) a numerical analysis of the angular distribution of EC absorption is carried out. An assessment of the accuracy of asymptotic expressions that have been given earlier is also performed, showing that these approximations can be usefully applied for calculating EC power losses from reactor-grade plasmas. Presented in part at the 14th Joint Workshop on Electron Cyclotron Emission and Electron Cyclotron Resonance Heating, Santorini, Greece, 9-12 May 2006.

40 CFR Appendix III to Part 266 - Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 28 2013-07-01 2013-07-01 false Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride III Appendix III to Part 266 Protection of Environment... to Part 266—Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride Terrain...

40 CFR Appendix III to Part 266 - Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 27 2014-07-01 2014-07-01 false Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride III Appendix III to Part 266 Protection of Environment... to Part 266—Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride Terrain...

40 CFR Appendix III to Part 266 - Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 27 2011-07-01 2011-07-01 false Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride III Appendix III to Part 266 Protection of Environment... to Part 266—Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride Terrain...

40 CFR Appendix III to Part 266 - Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 26 2010-07-01 2010-07-01 false Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride III Appendix III to Part 266 Protection of Environment... to Part 266—Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride Terrain...

40 CFR Appendix III to Part 266 - Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 28 2012-07-01 2012-07-01 false Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride III Appendix III to Part 266 Protection of Environment... to Part 266—Tier II Emission Rate Screening Limits for Free Chlorine and Hydrogen Chloride Terrain...

Differential affinity of BsSCO for Cu(II) and Cu(I) suggests a redox role in copper transfer to the Cu(A) center of cytochrome c oxidase.

PubMed

Hill, Bruce C; Andrews, Diann

2012-06-01

SCO (synthesis of cytochrome c oxidase) proteins are involved in the assembly of the respiratory chain enzyme cytochrome c oxidase acting to assist in the assembly of the Cu(A) center contained within subunit II of the oxidase complex. The Cu(A) center receives electrons from the reductive substrate ferrocytochrome c, and passes them on to the cytochrome a center. Cytochrome a feeds electrons to the oxygen reaction site composed of cytochrome a(3) and Cu(B). Cu(A) consists of two copper ions positioned within bonding distance and ligated by two histidine side chains, one methionine, a backbone carbonyl and two bridging cysteine residues. The complex structure and redox capacity of Cu(A) present a potential assembly challenge. SCO proteins are members of the thioredoxin family which led to the early suggestion of a disulfide exchange function for SCO in Cu(A) assembly, whereas the copper binding capacity of the Bacillus subtilis version of SCO (i.e., BsSCO) suggests a direct role for SCO proteins in copper transfer. We have characterized redox and copper exchange properties of apo- and metalated-BsSCO. The release of copper (II) from its complex with BsSCO is best achieved by reducing it to Cu(I). We propose a mechanism involving both disulfide and copper exchange between BsSCO and the apo-Cu(A) site. This article is part of a Special Issue entitled: Biogenesis/Assembly of Respiratory Enzyme Complexes. Copyright © 2011 Elsevier B.V. All rights reserved.

The Belle II Silicon Vertex Detector

NASA Astrophysics Data System (ADS)

Friedl, M.; Ackermann, K.; Aihara, H.; Aziz, T.; Bergauer, T.; Bozek, A.; Campbell, A.; Dingfelder, J.; Drasal, Z.; Frankenberger, A.; Gadow, K.; Gfall, I.; Haba, J.; Hara, K.; Hara, T.; Higuchi, T.; Himori, S.; Irmler, C.; Ishikawa, A.; Joo, C.; Kah, D. H.; Kang, K. H.; Kato, E.; Kiesling, C.; Kodys, P.; Kohriki, T.; Koike, S.; Kvasnicka, P.; Marinas, C.; Mayekar, S. N.; Mibe, T.; Mohanty, G. B.; Moll, A.; Negishi, K.; Nakayama, H.; Natkaniec, Z.; Niebuhr, C.; Onuki, Y.; Ostrowicz, W.; Park, H.; Rao, K. K.; Ritter, M.; Rozanska, M.; Saito, T.; Sakai, K.; Sato, N.; Schmid, S.; Schnell, M.; Shimizu, N.; Steininger, H.; Tanaka, S.; Tanida, K.; Taylor, G.; Tsuboyama, T.; Ueno, K.; Uozumi, S.; Ushiroda, Y.; Valentan, M.; Yamamoto, H.

2013-12-01

The KEKB machine and the Belle experiment in Tsukuba (Japan) are now undergoing an upgrade, leading to an ultimate luminosity of 8×1035 cm-2 s-1 in order to measure rare decays in the B system with high statistics. The previous vertex detector cannot cope with this 40-fold increase of luminosity and thus needs to be replaced. Belle II will be equipped with a two-layer Pixel Detector surrounding the beam pipe, and four layers of double-sided silicon strip sensors at higher radii than the old detector. The Silicon Vertex Detector (SVD) will have a total sensitive area of 1.13 m2 and 223,744 channels-twice as many as its predecessor. All silicon sensors will be made from 150 mm wafers in order to maximize their size and thus to reduce the relative contribution of the support structure. The forward part has slanted sensors of trapezoidal shape to improve the measurement precision and to minimize the amount of material as seen by particles from the vertex. Fast-shaping front-end amplifiers will be used in conjunction with an online hit time reconstruction algorithm in order to reduce the occupancy to the level of a few percent at most. A novel “Origami” chip-on-sensor scheme is used to minimize both the distance between strips and amplifier (thus reducing the electronic noise) as well as the overall material budget. This report gives an overview on the status of the Belle II SVD and its components, including sensors, front-end detector ladders, mechanics, cooling and the readout electronics.

Simultaneous Femtosecond X-ray Spectroscopy and Diffraction of Photosystem II at Room Temperature

PubMed Central

Kern, Jan; Alonso-Mori, Roberto; Tran, Rosalie; Hattne, Johan; Gildea, Richard J.; Echols, Nathaniel; Glöckner, Carina; Hellmich, Julia; Laksmono, Hartawan; Sierra, Raymond G.; Lassalle-Kaiser, Benedikt; Koroidov, Sergey; Lampe, Alyssa; Han, Guangye; Gul, Sheraz; DiFiore, Dörte; Milathianaki, Despina; Fry, Alan R.; Miahnahri, Alan; Schafer, Donald W.; Messerschmidt, Marc; Seibert, M. Marvin; Koglin, Jason E.; Sokaras, Dimosthenis; Weng, Tsu-Chien; Sellberg, Jonas; Latimer, Matthew J.; Grosse-Kunstleve, Ralf W.; Zwart, Petrus H.; White, William E.; Glatzel, Pieter; Adams, Paul D.; Bogan, Michael J.; Williams, Garth J.; Boutet, Sébastien; Messinger, Johannes; Zouni, Athina; Sauter, Nicholas K.; Yachandra, Vittal K.; Bergmann, Uwe; Yano, Junko

2013-01-01

Intense femtosecond X-ray pulses produced at the Linac Coherent Light Source (LCLS) were used for simultaneous X-ray diffraction (XRD) and X-ray emission spectroscopy (XES) of microcrystals of Photosystem II (PS II) at room temperature. This method probes the overall protein structure and the electronic structure of the Mn4CaO5 cluster in the oxygen-evolving complex of PS II. XRD data are presented from both the dark state (S1) and the first illuminated state (S2) of PS II. Our simultaneous XRD/XES study shows that the PS II crystals are intact during our measurements at the LCLS, not only with respect to the structure of PS II, but also with regard to the electronic structure of the highly radiation sensitive Mn4CaO5 cluster, opening new directions for future dynamics studies. PMID:23413188

Simultaneous femtosecond X-ray spectroscopy and diffraction of photosystem II at room temperature.

PubMed

Kern, Jan; Alonso-Mori, Roberto; Tran, Rosalie; Hattne, Johan; Gildea, Richard J; Echols, Nathaniel; Glöckner, Carina; Hellmich, Julia; Laksmono, Hartawan; Sierra, Raymond G; Lassalle-Kaiser, Benedikt; Koroidov, Sergey; Lampe, Alyssa; Han, Guangye; Gul, Sheraz; Difiore, Dörte; Milathianaki, Despina; Fry, Alan R; Miahnahri, Alan; Schafer, Donald W; Messerschmidt, Marc; Seibert, M Marvin; Koglin, Jason E; Sokaras, Dimosthenis; Weng, Tsu-Chien; Sellberg, Jonas; Latimer, Matthew J; Grosse-Kunstleve, Ralf W; Zwart, Petrus H; White, William E; Glatzel, Pieter; Adams, Paul D; Bogan, Michael J; Williams, Garth J; Boutet, Sébastien; Messinger, Johannes; Zouni, Athina; Sauter, Nicholas K; Yachandra, Vittal K; Bergmann, Uwe; Yano, Junko

2013-04-26

Intense femtosecond x-ray pulses produced at the Linac Coherent Light Source (LCLS) were used for simultaneous x-ray diffraction (XRD) and x-ray emission spectroscopy (XES) of microcrystals of photosystem II (PS II) at room temperature. This method probes the overall protein structure and the electronic structure of the Mn4CaO5 cluster in the oxygen-evolving complex of PS II. XRD data are presented from both the dark state (S1) and the first illuminated state (S2) of PS II. Our simultaneous XRD-XES study shows that the PS II crystals are intact during our measurements at the LCLS, not only with respect to the structure of PS II, but also with regard to the electronic structure of the highly radiation-sensitive Mn4CaO5 cluster, opening new directions for future dynamics studies.

Palladium and gold removal and recovery from precious metal solutions and electronic scrap leachates by Desulfovibrio desulfuricans.

PubMed

Creamer, Neil J; Baxter-Plant, Victoria S; Henderson, John; Potter, M; Macaskie, Lynne E

2006-09-01

Biomass of Desulfovibrio desulfuricans was used to recover Au(III) as Au(0) from test solutions and from waste electronic scrap leachate. Au(0) was precipitated extracellularly by a different mechanism from the biodeposition of Pd(0). The presence of Cu(2+) ( approximately 2000 mg/l) in the leachate inhibited the hydrogenase-mediated removal of Pd(II) but pre-palladisation of the cells in the absence of added Cu(2+) facilitated removal of Pd(II) from the leachate and more than 95% of the Pd(II) was removed autocatalytically from a test solution supplemented with Cu(II) and Pd(II). Metal recovery was demonstrated in a gas-lift electrobioreactor with electrochemically generated hydrogen, followed by precipitation of recovered metal under gravity. A 3-stage bioseparation process for the recovery of Au(III), Pd(II) and Cu(II) is proposed.

78 FR 37998 - Electronic One Touch Bingo System

Federal Register 2010, 2011, 2012, 2013, 2014

2013-06-25

... decision regarding the classification of server based electronic bingo system games that can be played... Class II or Class III game. DATES: The agency must receive comments on or before August 26, 2013... from the regulated community regarding the status of one touch bingo as a Class II or a Class III game...

Industrial Education. Electricity/Electronics Curriculum Guide, Phase II. Instructional Modules, Level II.

ERIC Educational Resources Information Center

Lillo, Robert E.; Soffiotto, Nicholas S.

Designed for students in the ninth grade, this electricity/electronics curriculum guide contains instructional modules for twenty-four units of instruction. Among the modules included are (1) introduction to the world of electricity, (2) electrical safety, (3) the electrical team, (4) resistance and resistors, (5) electric lamps and heating…

The rapidly metabolized 32,000-dalton polypeptide of the chloroplast is the "proteinaceous shield" regulating photosystem II electron transport and mediating diuron herbicide sensitivity.

PubMed Central

Mattoo, A K; Pick, U; Hoffman-Falk, H; Edelman, M

1981-01-01

Mild trypsin treatment of Spirodela oligorrhiza thylakoid membranes leads to partial digestion of the rapidly metabolized, surface-exposed, 32,000-dalton protein. Under these conditions, photoreduction of ferricyanide becomes insensitive to diuron [3-(3,4-dichlorophenyl)-1,1-dimethylurea], an inhibitor of photosystem II electron transport. Preincubation of thylakoids with diuron leads to a conformational change in the 32,000-dalton protein, modifying its trypsin digestion and preventing expression of diuron insensitivity. Finally, light affects the susceptibility of the 32,000-dalton protein to digestion by trypsin. In other experiments, thylakoids specifically depleted in the 32,000-dalton protein were found to be deficient in electron transport at the reducing side of photosystem II but not at the oxidizing side or in photosystem I activities. Thus, the rapidly metabolized 32,000-dalton thylakoid protein in Spirodela chloroplasts fulfills the requirements of the hypothesized "proteinaceous shield" [Renger, G. (1976) Biochim. Biophys. Acta 440, 287-300] regulating electron flow through photosystem II and mediating diuron sensitivity. Images PMID:6940173

Metastable Defect Formation at Microvoids Identified as a Source of Light-Induced Degradation in a-Si :H

NASA Astrophysics Data System (ADS)

Fehr, M.; Schnegg, A.; Rech, B.; Astakhov, O.; Finger, F.; Bittl, R.; Teutloff, C.; Lips, K.

2014-02-01

Light-induced degradation of hydrogenated amorphous silicon (a-Si :H), known as the Staebler-Wronski effect, has been studied by time-domain pulsed electron-paramagnetic resonance. Electron-spin echo relaxation measurements in the annealed and light-soaked state revealed two types of defects (termed type I and II), which can be discerned by their electron-spin echo relaxation. Type I exhibits a monoexponential decay related to indirect flip-flop processes between dipolar coupled electron spins in defect clusters, while the phase relaxation of type II is dominated by H1 nuclear spin dynamics and is indicative for isolated spins. We propose that defects are either located at internal surfaces of microvoids (type I) or are isolated and uniformly distributed in the bulk (type II). The concentration of both defect type I and II is significantly higher in the light-soaked state compared to the annealed state. Our results indicate that in addition to isolated defects, defects on internal surfaces of microvoids play a role in light-induced degradation of device-quality a-Si :H.

On the positronium spin conversion reactions caused by some macrocyclic Co II complexes

NASA Astrophysics Data System (ADS)

Fantola-Lazzarini, Anna L.; Lazzarini, Ennio

2002-08-01

The rate constants, kCR, of ortho- into para-positronium ( o-Ps→ p-Ps) spin conversion reactions, CR, caused by the high-spin [Co IIsep] 2+, [Co IIdinosar] 2+ and [Co IIdiamsar] 2+ macrocyclic complexes and also by high-spin [Co II sen] 2+ tripod complex were measured at several temperatures. The delocalizations, β, of Co II unpaired electrons, promoted by the mentioned ligands, were determined by using the previously established correlations between kCR and the electron delocalization β of unpaired metal electrons. β is given by the ratio between the Racah inter-electronic repulsion parameters of complexes, B, and that of the free ions, B0. The β values are compared with those of the Co II complexes with en (1,2-ethanediamine), pn (1,2 propanediamine) and dien (2,2' diamino diethylamine) ligands. The kCR rate constants are also compared with those of the Ps oxidation reactions, OR, promoted by the corresponding Co III complexes. It is concluded that, unlike OR's, the CR's do not occur by formation of hepta-coordinate adducts with Ps atoms.

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

PubMed

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

2013-05-20

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

Theoretical insights into the origin of magnetic exchange and magnetic anisotropy in {Re(IV)-M(II)} (M = Mn, Fe, Co, Ni and Cu) single chain magnets.

PubMed

Singh, Saurabh Kumar; Vignesh, Kuduva R; Archana, Velloth; Rajaraman, Gopalan

2016-05-10

Density functional calculations have been performed on a series of {Re(IV)-M(II)} (M = Mn(), Fe(), Co(), Ni(), Cu()) complexes to compute the magnetic exchange interaction between the Re(IV) and M(II) ions, and understand the mechanism of magnetic coupling in this series. DFT calculations yield J values of -5.54 cm(-1), +0.44 cm(-1), +10.5 cm(-1), +4.54 cm(-1) and +19 cm(-1) for complexes respectively, and these estimates are in general agreement with the experimental reports. Using molecular orbital (MO) and overlap integral analysis, we have established a mechanism of coupling for a {3d-5d} pair and the proposed mechanism rationalises both the sign and the magnitude of J values observed in this series. Our proposed mechanism of coupling has five contributing factors: (i) (Re)dyz-dyz(3d) overlap, (ii) (Re)dxz-dxz(3d) overlap, (iii) (Re)dxy-dxy(3d) overlap, (iv) (Re)eg-t2g(3d) overlaps and (v) (Re)eg-eg(3d) overlaps. Here, the first two terms are found to contribute to the antiferromagnetic part of the exchange, while the other three contribute to the ferromagnetic part. The last two terms correspond to the cross-interactions and also contribute to the ferromagnetic part of the exchange. A record high ferromagnetic J value observed for the {Re(IV)-Cu(II)} pair in complex is found to be due to a significant cross interaction between the dz(2) orbital of the Re(IV) ion and the dx(2)-y(2) orbital of the Cu(ii) ion. Magneto-structural correlations are developed for Re-C and M-N bond lengths and Re-C-N and M-N-C bond angles. Among the developed correlations, the M-N-C bond angle is found to be the most sensitive parameter which influences the sign and strength of J values in this series. The J values are found to be more positive (or less negative) as the angle increases, indicating stronger ferromagnetic coupling at linear M-N-C angles. Apart from the magnetic exchange interaction, we have also estimated the magnetic anisotropy of [ReCl4(CN)2](2-) and [(DMF)4(CN)M(II)(CN)] (M(II)-Fe(II), Co(II) and Ni(II)) units using the state-of-the-art ab initio CASSCF/PT2/RASSI-SO/SINGLE_ANISO approach. The calculated D and E values for these building units are found to be in agreement with the available experimental results. Particularly a large positive D computed for the [ReCl4(CN)2](2-) unit was found to arise from dxz/dyz → dxy excitations corresponding to the low-lying doublet states. Similarly, a very large positive D value computed for Fe(II) and Co(II) units are also rationalised based on the corresponding ground state electronic configurations computed. The non-collinearity of the Re(IV) ion and the M(II) ion axial anisotropy (DZZ) axis are found to diminish the anisotropy of the building unit, leading to the observation of moderate relaxation barriers for these molecules.

Modeling the active site of [NiFe] hydrogenases and the [NiFeu] subsite of the C-cluster of carbon monoxide dehydrogenases: low-spin iron(II) versus high-spin iron(II).

PubMed

Weber, Katharina; Erdem, Özlen F; Bill, Eckhard; Weyhermüller, Thomas; Lubitz, Wolfgang

2014-06-16

A series of four [S2Ni(μ-S)2FeCp*Cl] compounds with different tetradentate thiolate/thioether ligands bound to the Ni(II) ion is reported (Cp* = C5Me5). The {S2Ni(μ-S)2Fe} core of these compounds resembles structural features of the active site of [NiFe] hydrogenases. Detailed analyses of the electronic structures of these compounds by Mössbauer and electron paramagnetic resonance spectroscopy, magnetic measurements, and density functional theory calculations reveal the oxidation states Ni(II) low spin and Fe(II) high spin for the metal ions. The same electronic configurations have been suggested for the Cred1 state of the C-cluster [NiFeu] subsite in carbon monoxide dehydrogenases (CODH). The Ni-Fe distance of ∼3 Å excludes a metal-metal bond between nickel and iron, which is in agreement with the computational results. Electrochemical experiments show that iron is the redox active site in these complexes, performing a reversible one-electron oxidation. The four complexes are discussed with regard to their similarities and differences both to the [NiFe] hydrogenases and the C-cluster of Ni-containing CODH.

Efficient Destruction of Pollutants in Water by a Dual-Reaction-Center Fenton-like Process over Carbon Nitride Compounds-Complexed Cu(II)-CuAlO2.

PubMed

Lyu, Lai; Yan, Dengbiao; Yu, Guangfei; Cao, Wenrui; Hu, Chun

2018-04-03

Carbon nitride compounds (CN) complexed with the in-situ-produced Cu(II) on the surface of CuAlO 2 substrate (CN-Cu(II)-CuAlO 2 ) is prepared via a surface growth process for the first time and exhibits exceptionally high activity and efficiency for the degradation of the refractory pollutants in water through a Fenton-like process in a wide pH range. The reaction rate for bisphenol A removal is ∼25 times higher than that of the CuAlO 2 . According to the characterization, Cu(II) generation on the surface of CuAlO 2 during the surface growth process results in the marked decrease of the surface oxygen vacancies and the formation of the C-O-Cu bridges between CN and Cu(II)-CuAlO 2 in the catalyst. The electron paramagnetic resonance (EPR) analysis and density functional theory (DFT) calculations demonstrate that the dual reaction centers are produced around the Cu and C sites due to the cation-π interactions through the C-O-Cu bridges in CN-Cu(II)-CuAlO 2 . During the Fenton-like reactions, the electron-rich center around Cu is responsible for the efficient reduction of H 2 O 2 to • OH, and the electron-poor center around C captures electrons from H 2 O 2 or pollutants and diverts them to the electron-rich area via the C-O-Cu bridge. Thus, the catalyst exhibits excellent catalytic performance for the refractory pollutant degradation. This study can deepen our understanding on the enhanced Fenton reactivity for water purification through functionalizing with organic solid-phase ligands on the catalyst surface.

Single turnover studies of oxidative halophenol dehalogenation by horseradish peroxidase reveal a mechanism involving two consecutive one electron steps: toward a functional halophenol bioremediation catalyst.

PubMed

Sumithran, Suganya; Sono, Masanori; Raner, Gregory M; Dawson, John H

2012-12-01

Horseradish peroxidase (HRP) catalyzes the oxidative para-dechlorination of the environmental pollutant/carcinogen 2,4,6-trichlorophenol (2,4,6-TCP). A possible mechanism for this reaction is a direct oxygen atom transfer from HRP compound I (HRP I) to trichlorophenol to generate 2,6-dichloro 1,4-benzoquinone, a two-electron transfer process. An alternative mechanism involves two consecutive one-electron transfer steps in which HRP I is reduced to compound II (HRP II) and then to the ferric enzyme as first proposed by Wiese et al. [F.W. Wiese, H.C. Chang, R.V. Lloyd, J.P. Freeman, V.M. Samokyszyn, Arch. Environ. Contam. Toxicol. 34 (1998) 217-222]. To probe the mechanism of oxidative halophenol dehalogenation, the reactions between 2,4,6-TCP and HRP compounds I or II have been investigated under single turnover conditions (i.e., without excess H(2)O(2)) using rapid scan stopped-flow spectroscopy. Addition of 2,4,6-TCP to HRP I leads rapidly to HRP II and then more slowly to the ferric resting state, consistent with a mechanism involving two consecutive one-electron oxidations of the substrate via a phenoxy radical intermediate. HRP II can also directly dechlorinate 2,4,6-TCP as judged by rapid scan stopped-flow and mass spectrometry. This observation is particularly significant since HRP II can only carry out one-electron oxidations. A more detailed understanding of the mechanism of oxidative halophenol dehalogenation will facilitate the use of HRP as a halophenol bioremediation catalyst. Copyright © 2012 Elsevier Inc. All rights reserved.

40 CFR Appendix II to Part 1054 - Duty Cycles for Laboratory Testing

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Duty Cycles for Laboratory Testing II.... 1054, App. II Appendix II to Part 1054—Duty Cycles for Laboratory Testing (a) Test handheld engines with the following steady-state duty cycle: G3 mode No. Engine speed a Torque(percent) b Weighting...

AT2 DS II - Accelerator System Design (Part II) - CCC Video Conference

ScienceCinema

None

2017-12-09

Discussion Session - Accelerator System Design (Part II) Tutors: C. Darve, J. Weisend II, Ph. Lebrun, A. Dabrowski, U. Raich Video Conference with the CERN Control Center. Experts in the field of Accelerator science will be available to answer the students questions. This session will link the CCC and SA (using Codec VC).

Homoleptic nickel(II) complexes of redox-tunable pincer-type ligands.

PubMed

Hewage, Jeewantha S; Wanniarachchi, Sarath; Morin, Tyler J; Liddle, Brendan J; Banaszynski, Megan; Lindeman, Sergey V; Bennett, Brian; Gardinier, James R

2014-10-06

Different synthetic methods have been developed to prepare eight new redox-active pincer-type ligands, H(X,Y), that have pyrazol-1-yl flanking donors attached to an ortho-position of each ring of a diarylamine anchor and that have different groups, X and Y, at the para-aryl positions. Together with four previously known H(X,Y) ligands, a series of 12 Ni(X,Y)2 complexes were prepared in high yields by a simple one-pot reaction. Six of the 12 derivatives were characterized by single-crystal X-ray diffraction, which showed tetragonally distorted hexacoordinate nickel(II) centers. The nickel(II) complexes exhibit two quasi-reversible one-electron oxidation waves in their cyclic voltammograms, with half-wave potentials that varied over a remarkable 700 mV range with the average of the Hammett σ(p) parameters of the para-aryl X, Y groups. The one- and two-electron oxidized derivatives [Ni(Me,Me)2](BF4)n (n = 1, 2) were prepared synthetically, were characterized by X-band EPR, electronic spectroscopy, and single-crystal X-ray diffraction (for n = 2), and were studied computationally by DFT methods. The dioxidized complex, [Ni(Me,Me)2](BF4)2, is an S = 2 species, with nickel(II) bound to two ligand radicals. The mono-oxidized complex [Ni(Me,Me)2](BF4), prepared by comproportionation, is best described as nickel(II) with one ligand centered radical. Neither the mono- nor the dioxidized derivative shows any substantial electronic coupling between the metal and their bound ligand radicals because of the orthogonal nature of their magnetic orbitals. On the other hand, weak electronic communication occurs between ligands in the mono-oxidized complex as evident from the intervalence charge transfer (IVCT) transition found in the near-IR absorption spectrum. Band shape analysis of the IVCT transition allowed comparisons of the strength of the electronic interaction with that in the related, previously known, Robin-Day class II mixed valence complex, [Ga(Me,Me)2](2+).

Subseabed disposal program annual report, January-December 1980. Volume II. Appendices (principal investigator progress reports). Part 1

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

Hinga, K.R.

Volume II of the sixth annual report describing the progress and evaluating the status of the Subseabed Disposal Program contains the appendices referred to in Volume I, Summary and Status. Because of the length of Volume II, it has been split into two parts for publication purposes. Part 1 contains Appendices A-Q; Part 2 contains Appendices R-MM. Separate abstracts have been prepared for each appendix for inclusion in the Energy Data Base.

From Geometry Optimization to Time Dependent Molecular Structure Modeling: Method Developments, ab initio Theories and Applications

NASA Astrophysics Data System (ADS)

Liang, Wenkel

This dissertation consists of two general parts: (I) developments of optimization algorithms (both nuclear and electronic degrees of freedom) for time-independent molecules and (II) novel methods, first-principle theories and applications in time dependent molecular structure modeling. In the first part, we discuss in specific two new algorithms for static geometry optimization, the eigenspace update (ESU) method in nonredundant internal coordinate that exhibits an enhanced performace with up to a factor of 3 savings in computational cost for large-sized molecular systems; the Car-Parrinello density matrix search (CP-DMS) method that enables direct minimization of the SCF energy as an effective alternative to conventional diagonalization approach. For the second part, we consider the time dependence and first presents two nonadiabatic dynamic studies that model laser controlled molecular photo-dissociation for qualitative understandings of intense laser-molecule interaction, using ab initio direct Ehrenfest dynamics scheme implemented with real-time time-dependent density functional theory (RT-TDDFT) approach developed in our group. Furthermore, we place our special interest on the nonadiabatic electronic dynamics in the ultrafast time scale, and presents (1) a novel technique that can not only obtain energies but also the electron densities of doubly excited states within a single determinant framework, by combining methods of CP-DMS with RT-TDDFT; (2) a solvated first-principles electronic dynamics method by incorporating the polarizable continuum solvation model (PCM) to RT-TDDFT, which is found to be very effective in describing the dynamical solvation effect in the charge transfer process and yields a consistent absorption spectrum in comparison to the conventional linear response results in solution. (3) applications of the PCM-RT-TDDFT method to study the intramolecular charge-transfer (CT) dynamics in a C60 derivative. Such work provides insights into the characteristics of ultrafast dynamics in photoexcited fullerene derivatives, and aids in the rational design for pre-dissociative exciton in the intramolecular CT process in organic solar cells.

Distinguishing between Dexter and rapid sequential electron transfer in covalently linked donor-acceptor assemblies.

PubMed

Soler, Monica; McCusker, James K

2008-04-09

The syntheses, physical, and photophysical properties of a family of complexes having the general formula [M2(L)(mcb)(Ru(4,4'-(X)2-bpy)2)](PF6)3 (where M = Mn(II) or Zn(II), X = CH3 or CF3, mcb is 4'-methyl-4-carboxy-2,2'-bipyridine, and L is a Schiff base macrocycle derived from 2,6-diformyl-4-methylphenol and bis(2-aminoethyl)-N-methylamine) are described. The isostructural molecules all consist of dinuclear metal cores covalently linked to a Ru(II) polypyridyl complex. Photoexcitation of [Mn2(L)(mcb)(Ru((CF3)2-bpy)2)](PF6)3 (4) in deoxygenated CH2Cl2 solution results in emission characteristic of the 3MLCT excited state of the Ru(II) chromophore but with a lifetime (tau(obs) = 5.0 +/- 0.1 ns) and radiative quantum yield (Phi(r) approximately 7 x 10(-4)) that are significantly attenuated relative to the Zn(II) model complex [Zn2(L)(mcb)(Ru((CF3)2-bpy)2)](PF6)3 (6) (tau(obs) = 730 +/- 30 ns and Phi(r) = 0.024, respectively). Quenching of the 3MLCT excited state is even more extensive in the case of [Mn2(L)(mcb)(Ru((CH3)2-bpy)2)](PF6)3 (3), whose measured lifetime (tau(obs) = 45 +/- 5 ps) is >10(4) shorter than the corresponding model complex [Zn2(L)(mcb)(Ru((CH3)2-bpy)2)](PF6)3 (5) (tau(obs) = 1.31 +/- 0.05 micros). Time-resolved absorption measurements on both Mn-containing complexes at room-temperature revealed kinetics that were independent of probe wavelength; no spectroscopic signatures for electron-transfer photoproducts were observed. Time-resolved emission data for complex 4 acquired in CH2Cl2 solution over a range of 200-300 K could be fit to an expression of the form k(nr) = k0 + A x exp{-DeltaE/kB T} with k0 = 1.065 +/- 0.05 x 10(7) s(-1), A = 3.7 +/- 0.5 x 10(10) s(-1), and DeltaE = 1230 +/- 30 cm(-1). Assuming an electron-transfer mechanism, the variable-temperature data on complex 4 would require a reorganization energy of lambda approximately 0.4-0.5 eV which is too small to be associated with charge separation in this system. This result coupled with the lack of enhanced emission at temperatures below the glass-to-fluid transition of the solvent and the absence of visible absorption features associated with the Mn(II)2 core allows for a definitive assignment of Dexter transfer as the dominant excited-state reaction pathway. A similar conclusion was reached for complex 3 based in part on the smaller driving force for electron transfer (DeltaG0(ET) = -0.1 eV), the increase in probability of Dexter transfer due to the closer proximity of the donor excited state to the dimanganese acceptor, and a lack of emission from the compound upon formation of an optical glass at 80 K. Electronic coupling constants for Dexter transfer were determined to be approximately 10 cm(-1) and approximately 0.15 cm(-1) in complexes 3 and 4, respectively, indicating that the change in spatial localization of the excited state from the bridge (complex 3) to the periphery of the chromophore (complex 4) results in a decrease in electronic coupling to the dimanganese core of nearly 2 orders of magnitude. In addition to providing insight into the influence of donor/acceptor proximity on exchange energy transfer, this study underscores the utility of variable-temperature measurements in cases where Dexter and electron-transfer mechanisms can lead to indistinguishable spectroscopic observables.

Experimental Measurements of the Secondary Electron Yield in the Experimental Measurement of the Secondary Electron Yield in the PEP-II Particle Accelerator Beam Line

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

Pivi, M.T.F.; Collet, G.; King, F.

Beam instability caused by the electron cloud has been observed in positron and proton storage rings and it is expected to be a limiting factor in the performance of the positron Damping Ring (DR) of future Linear Colliders (LC) such as ILC and CLIC. To test a series of promising possible electron cloud mitigation techniques as surface coatings and grooves, in the Positron Low Energy Ring (LER) of the PEP-II accelerator, we have installed several test vacuum chambers including (i) a special chamber to monitor the variation of the secondary electron yield of technical surface materials and coatings under themore » effect of ion, electron and photon conditioning in situ in the beam line; (ii) chambers with grooves in a straight magnetic-free section; and (iii) coated chambers in a dedicated newly installed 4-magnet chicane to study mitigations in a magnetic field region. In this paper, we describe the ongoing R&D effort to mitigate the electron cloud effect for the LC damping ring, focusing on the first experimental area and on results of the reduction of the secondary electron yield due to in situ conditioning.« less

Hydrogen peroxide and dioxygen activation by dinuclear copper complexes in aqueous solution: hydroxyl radical production initiated by internal electron transfer.

PubMed

Zhu, Qing; Lian, Yuxiang; Thyagarajan, Sunita; Rokita, Steven E; Karlin, Kenneth D; Blough, Neil V

2008-05-21

Dinuclear Cu(II) complexes, CuII2Nn (n = 4 or 5), were recently found to specifically cleave DNA in the presence of a reducing thiol and O2 or in the presence of H2O2 alone. However, CuII2N3 and a closely related mononuclear Cu(II) complex exhibited no selective reaction under either condition. Spectroscopic studies indicate an intermediate is generated from CuII2Nn (n = 4 or 5) and mononuclear Cu(II) solutions in the presence of H2O2 or from CuI2Nn (n = 4 or 5) in the presence of O2. This intermediate decays to generate OH radicals and ligand degradation products at room temperature. The lack of reactivity of the intermediate with a series of added electron donors suggests the intermediate discharges through a rate-limiting intramolecular electron transfer from the ligand to the metal peroxo center to produce an OH radical and a ligand-based radical. These results imply that DNA cleavage does not result from direct reaction with a metal-peroxo intermediate but instead arises from reaction with either OH radicals or ligand-based radicals.

High Electrochemical Sensitivity of TiO2- x Nanosheets and an Electron-Induced Mutual Interference Effect toward Heavy Metal Ions Demonstrated Using X-ray Absorption Fine Structure Spectra.

PubMed

Zhou, Wen-Yi; Li, Shan-Shan; Song, Jie-Yao; Jiang, Min; Jiang, Tian-Jia; Liu, Jin-Yun; Liu, Jin-Huai; Huang, Xing-Jiu

2018-04-03

Mutual interference is a severe issue that occurs during the electrochemical detection of heavy metal ions. This limitation presents a notable drawback for its high sensitivity to specific targets. Here, we present a high electrochemical sensitivity of ∼237.1 μA cm -2 μM -1 toward copper(II) [Cu(II)] based on oxygen-deficient titanium dioxide (TiO 2- x ) nanosheets. We fully demonstrated an atomic-level relationship between electrochemical behaviors and the key factors, including the high-energy (001) facet percentage, oxygen vacancy concentration, surface -OH content, and charge carrier density, is fully demonstrated. These four factors were quantified using Raman, electron spin resonance, X-ray photoelectron spectroscopy spectra, and Mott-Schottky plots. In the mutual interference investigation, we selected cadmium(II) [Cd(II)] as the target ion because of the significant difference in its stripping potential (∼700 mV). The results show that the Cd(II) can enhance the sensitivity of TiO 2- x nanosheets toward Cu(II), exhibiting an electron-induced mutual interference effect, as demonstrated by X-ray absorption fine structure spectra.

Intramolecular electron transfer in cyanide bridged adducts comprising Ru(II)/Ru(III) tetracarboxylate and [Mn(I)(CO)(CN)((t)BuNC)(4)] units.

PubMed

Imhof, Wolfgang; Sterzik, Anke; Krieck, Sven; Schwierz, Markus; Hoffeld, Thomas; Spielberg, Eike T; Plass, Winfried; Patmore, Nathan

2010-07-21

Reaction of mixed valence ruthenium tetracarboxylates [Ru(2)(II,III)(R(1)COO)(2)(R(2)COO)(2)Cl] (R(1) = Me, R(2) = 2,4,6-(i)Pr-Ph or R(1) = R(2) = (t)Bu) with two equivalents of the octahedral manganese complex [Mn(I)(CO)(CN)((t)BuNC)(4)] leads to the formation of cyanide bridged heteronuclear coordination compounds of the general formula {[Ru(2)(II,III)(R(1)COO)(2)(R(2)COO)(2)][Mn(I)(CO)(CN)((t)BuNC)(4)](2)}Cl. In solution an intramolecular electron transfer from manganese towards the multiply bonded Ru(2) core occurs that is verified by EPR and IR spectroscopy, magnetic measurements and DFT calculations. Nevertheless, disproportionation of an initially formed {Mn(I)-Ru(2)(II,III)-Mn(I)}(+) adduct into {Mn(II)-Ru(2)(II,III)-Mn(I)}(2+) and {Mn(I)-Ru(2)(II,II)-Mn(I)} species cannot be completely ruled out.

Synthesis and CV Studies of Dithiol-terminated Metal Terpyridine Complexes

NASA Technical Reports Server (NTRS)

Asano, Sylvia; Fan, Wendy; Ng, Hou-Tee; Han, Jie; Meyyappan, M.

2003-01-01

Transition metal coordination complexes possess unique electronic structures that should be a good model for studying electronic transport behavior at a molecular level. The discrete, multiple redox states, low redox potential and the superb ability to establish contact with other molecular and electronic components by coordination chemistry have made this a subject of investigation for their possible application as active electronic components in molecular devices. We present the synthesis and electrochemical characterization of 4'-thioacetylphenyl-2'2:6',2"-terpyridine iron(II) complex and compare it with a model bis-terpyridine iron(II) complex by cyclic voltammetry. With the use of different working electrodes, the behavior of these complexes show different electron transfer rates.

Manganese Binding Properties of Human Calprotectin Under Conditions of High and Low Calcium: X-ray Crystallographic and Advanced EPR Spectroscopic Analysis

PubMed Central

Gagnon, Derek M.; Brophy, Megan Brunjes; Bowman, Sarah E. J.; Stich, Troy A.; Drennan, Catherine L.; Britt, R. David; Nolan, Elizabeth M.

2015-01-01

The antimicrobial protein calprotectin (CP), a hetero-oligomer of the S100 family members S100A8 and S100A9, is the only identified mammalian Mn(II)-sequestering protein. Human CP uses Ca(II) ions to tune its Mn(II) affinity at a biologically unprecedented hexahistidine site that forms at the S100A8/S100A9 interface, and the molecular basis for this phenomenon requires elucidation. Herein, we investigate the remarkable Mn(II) coordination chemistry of human CP using X-ray crystallography as well as continuous wave (CW) and pulse electron paramagnetic resonance (EPR) spectroscopies. An X-ray crystallographic structure of Mn(II)-CP containing one Mn(II), two Ca(II), and two Na(I) ions per CP heterodimer is reported. The CW EPR spectrum of Ca(II)- and Mn(II)-bound CP prepared with a 10:0.9:1 Ca(II):Mn(II):CP ratio is characterized by an unusually low zero-field splitting of 485 MHz (E/D = 0.30) for the S = 5/2 Mn(II) ion, consistent with the high symmetry of the His6 binding site observed crystallographically. Results from electron spin-echo envelope modulation and electron nuclear double resonance experiments reveal that the six Mn(II)-coordinating histidine residues of Ca(II)- and Mn(II)-bound CP are spectroscopically equivalent. The observed 15N (I = 1/2) hyperfine couplings (A) arise from two distinct classes of nitrogen atoms: the coordinating ε-nitrogen of the imidazole ring of each histidine ligand (A = [3.45, 3.71, 5.91] MHz) and the distal δ-nitrogen (A = [0.11, 0.18, 0.42] MHz). In the absence of Ca(II), the binding affinity of CP for Mn(II) drops by ca. two orders of magnitude and coincides with Mn(II) binding at the His6 site as well as other sites. This study demonstrates the role of Ca(II) in enabling high-affinity and specific binding of Mn(II) to the His6 site of human calprotectin. PMID:25597447

Manganese Binding Properties of Human Calprotectin under Conditions of High and Low Calcium: X-ray Crystallographic and Advanced Electron Paramagnetic Resonance Spectroscopic Analysis

DOE PAGES

Gagnon, Derek M.; Brophy, Megan Brunjes; Bowman, Sarah E. J.; ...

2015-01-18

The antimicrobial protein calprotectin (CP), a hetero-oligomer of the S100 family members S100A8 and S100A9, is the only identified mammalian Mn(II)-sequestering protein. Human CP uses Ca(II) ions to tune its Mn(II) affinity at a biologically unprecedented hexahistidine site that forms at the S100A8/S100A9 interface, and the molecular basis for this phenomenon requires elucidation. Here in this paper, we investigate the remarkable Mn(II) coordination chemistry of human CP using X-ray crystallography as well as continuous-wave (CW) and pulse electron paramagnetic resonance (EPR) spectroscopies. An X-ray crystallographic structure of Mn(II)-CP containing one Mn(II), two Ca(II), and two Na(I) ions per CP heterodimermore » is reported. The CW EPR spectrum of Ca(II)- and Mn(II)-bound CP prepared with a 10:0.9:1 Ca(II):Mn(II):CP ratio is characterized by an unusually low zero-field splitting of 485 MHz (E/D = 0.30) for the S = 5/2 Mn(II) ion, consistent with the high symmetry of the His6 binding site observed crystallographically. Results from electron spin–echo envelope modulation and electron–nuclear double resonance experiments reveal that the six Mn(II)-coordinating histidine residues of Ca(II)- and Mn(II)-bound CP are spectroscopically equivalent. The observed 15N (I = 1/2) hyperfine couplings (A) arise from two distinct classes of nitrogen atoms: the coordinating ε-nitrogen of the imidazole ring of each histidine ligand (A = [3.45, 3.71, 5.91] MHz) and the distal δ-nitrogen (A = [0.11, 0.18, 0.42] MHz). In the absence of Ca(II), the binding affinity of CP for Mn(II) drops by two to three orders of magnitude and coincides with Mn(II) binding at the His6 site as well as other sites. This study demonstrates the role of Ca(II) in enabling high-affinity and specific binding of Mn(II) to the His 6 site of human calprotectin.« less

Manganese Binding Properties of Human Calprotectin under Conditions of High and Low Calcium: X-ray Crystallographic and Advanced Electron Paramagnetic Resonance Spectroscopic Analysis

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

Gagnon, Derek M.; Brophy, Megan Brunjes; Bowman, Sarah E. J.

The antimicrobial protein calprotectin (CP), a hetero-oligomer of the S100 family members S100A8 and S100A9, is the only identified mammalian Mn(II)-sequestering protein. Human CP uses Ca(II) ions to tune its Mn(II) affinity at a biologically unprecedented hexahistidine site that forms at the S100A8/S100A9 interface, and the molecular basis for this phenomenon requires elucidation. Here in this paper, we investigate the remarkable Mn(II) coordination chemistry of human CP using X-ray crystallography as well as continuous-wave (CW) and pulse electron paramagnetic resonance (EPR) spectroscopies. An X-ray crystallographic structure of Mn(II)-CP containing one Mn(II), two Ca(II), and two Na(I) ions per CP heterodimermore » is reported. The CW EPR spectrum of Ca(II)- and Mn(II)-bound CP prepared with a 10:0.9:1 Ca(II):Mn(II):CP ratio is characterized by an unusually low zero-field splitting of 485 MHz (E/D = 0.30) for the S = 5/2 Mn(II) ion, consistent with the high symmetry of the His6 binding site observed crystallographically. Results from electron spin–echo envelope modulation and electron–nuclear double resonance experiments reveal that the six Mn(II)-coordinating histidine residues of Ca(II)- and Mn(II)-bound CP are spectroscopically equivalent. The observed 15N (I = 1/2) hyperfine couplings (A) arise from two distinct classes of nitrogen atoms: the coordinating ε-nitrogen of the imidazole ring of each histidine ligand (A = [3.45, 3.71, 5.91] MHz) and the distal δ-nitrogen (A = [0.11, 0.18, 0.42] MHz). In the absence of Ca(II), the binding affinity of CP for Mn(II) drops by two to three orders of magnitude and coincides with Mn(II) binding at the His6 site as well as other sites. This study demonstrates the role of Ca(II) in enabling high-affinity and specific binding of Mn(II) to the His 6 site of human calprotectin.« less

Temperature Independent Catalytic Two-Electron Reduction of Dioxygen by Ferrocenes with a Tris[2-(2-pyridyl)ethyl]amine-Copper(II) Catalyst in the Presence of Perchloric Acid

PubMed Central

Das, Dipanwita; Lee, Yong-Min; Ohkubo, Kei; Nam, Wonwoo; Karlin, Kenneth D.; Fukuzumi, Shunichi

2013-01-01

Selective two-electron plus two-proton (2e−/2H+) reduction of O2 to hydrogen peroxide by ferrocene (Fc) or 1,1′-dimethylferrocene (Me2Fc) in the presence of perchloric acid is catalyzed efficiently by a mononuclear copper(II) complex, [CuII(tepa)]2+ {tepa = tris[2-(2-pyridyl)ethyl]amine} (1) in acetone. The E1/2 value for [CuII(tepa)]2+ as measured by cyclic voltammetry is 0.07 V vs Fc/Fc+ in acetone, being significantly positive, which makes it possible to use relatively weak one-electron reductants such as Fc and Me2Fc for the overall two-electron reduction of O2. Fast electron transfer from Fc or Me2Fc to 1 affords the corresponding CuI complex, [CuI(tepa)]+ (2), which reacts at low temperature (193 K) with O2, however only in presence of HClO4 to afford the hydroperoxo complex, [CuII(tepa)(OOH)]2+ (3). The detailed kinetic study on the homogeneous catalytic system reveals the rate-determining step to be the O2-binding process in the presence of HClO4 at lower temperature as well as at room temperature. The O2-binding kinetics in the presence of HClO4 were studied, demonstrating that the rate of formation of the hydroperoxo complex (3) as well as the overall catalytic reaction remained virtually the same with changing temperature. The apparent lack of an activation energy for the catalytic two-electron reduction of O2 is shown to result from the existence of a pre-equilibrium between 2 and O2 prior to the formation of the hydroperoxo complex 3. No further reduction of [CuII(tepa)(OOH)]2+ (3) by Fc or Me2Fc occurred, and instead 3 is protonated by HClO4 to yield H2O2 accompanied by regeneration of 1, thus completing the catalytic cycle for the two-electron reduction of O2 by Fc or Me2Fc. PMID:23394287

Fourth - generation languages. Volume 2. Representative 4GLs

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

Martin, J.

1986-01-01

The chapters in Part II each describe one representative product marketed by a vendor other than IBM. (Volume III of this work covers IBM languages.) The chapters in Part II cover the following 4GLs: ADS/ONLINE, APPLICATION FACTORY, DATATRIEVE, FOCUS, IDEAL, INTELLECT, MANTIS, MIMER, NATURAL, NOMAD2, RAMIS II, SYSTEM W, and USE-IT. The Perspective section of Part II presents a general overview of the product and describes its role in the marketplace. The Tutorial section describes how a user employs the language in application development.

Neutron Energy and Time-of-flight Spectra Behind the Lateral Shield of a High Energy Electron Accelerator Beam Dump, Part II: Monte Carlo Simulations

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

Roesler, Stefan

2002-09-19

Energy spectra of high-energy neutrons and neutron time-of-flight spectra were calculated for the setup of experiment T-454 performed with a NE213 liquid scintillator at the Final Focus Test Beam (FFTB) facility at the Stanford Linear Accelerator Center. The neutrons were created by the interaction a 28.7 GeV electron beam in the aluminum beam dump of the FFTB which is housed inside a thick steel and concrete shielding. In order to determine the attenuation length of high-energy neutrons additional concrete shielding of various thicknesses was placed outside the existing shielding. The calculations were performed using the FLUKA interaction and transport code.more » The energy and time-of-flight were recorded for the location of the detector allowing a detailed comparison with the experimental data. A generally good description of the data is achieved adding confidence to the use of FLUKA for the design of shielding for high-energy electron accelerators.« less

Cell death in a harmful algal bloom causing species Alexandrium tamarense upon an algicidal bacterium induction.

PubMed

Zhang, Huajun; Lv, Jinglin; Peng, Yun; Zhang, Su; An, Xinli; Xu, Hong; Zhang, Jun; Tian, Yun; Zheng, Wei; Zheng, Tianling

2014-09-01

Harmful algal blooms occur throughout the world, destroying aquatic ecosystems and threatening human health. The culture supernatant of the marine algicidal bacteria DHQ25 was able to lysis dinoflagellate Alexandrium tamarense. Loss of photosynthetic pigments, accompanied by a decline in Photosystem II (PSII) photochemical efficiency (Fv/Fm), in A. tamarense was detected under bacterial supernatant stress. Transmission electron microscope analysis showed obvious morphological modifications of chloroplast dismantling as a part of the algicidal process. The PSII electron transport chain was seriously blocked, with its reaction center damaged. This damage was detected in a relative transcriptional level of psbA and psbD genes, which encode the D1 and D2 proteins in the PSII reaction center. And the block in the electron transport chain of PSII might generate excessive reactive oxygen species (ROS) which could destroy the membrane system and pigment synthesis and activated enzymic antioxidant systems including superoxide dismutase (SOD) and catalase (CAT). This study indicated that marine bacteria with indirect algicidal activity played an important role in the changes of photosynthetic process in a harmful algal bloom species.

Self-consistent modeling of electron cyclotron resonance ion sources

NASA Astrophysics Data System (ADS)

Girard, A.; Hitz, D.; Melin, G.; Serebrennikov, K.; Lécot, C.

2004-05-01

In order to predict the performances of electron cyclotron resonance ion source (ECRIS), it is necessary to perfectly model the different parts of these sources: (i) magnetic configuration; (ii) plasma characteristics; (iii) extraction system. The magnetic configuration is easily calculated via commercial codes; different codes also simulate the ion extraction, either in two dimension, or even in three dimension (to take into account the shape of the plasma at the extraction influenced by the hexapole). However the characteristics of the plasma are not always mastered. This article describes the self-consistent modeling of ECRIS: we have developed a code which takes into account the most important construction parameters: the size of the plasma (length, diameter), the mirror ratio and axial magnetic profile, whether a biased probe is installed or not. These input parameters are used to feed a self-consistent code, which calculates the characteristics of the plasma: electron density and energy, charge state distribution, plasma potential. The code is briefly described, and some of its most interesting results are presented. Comparisons are made between the calculations and the results obtained experimentally.

Absorption enhancement in type-II coupled quantum rings due to existence of quasi-bound states

NASA Astrophysics Data System (ADS)

Hsieh, Chi-Ti; Lin, Shih-Yen; Chang, Shu-Wei

2018-02-01

The absorption of type-II nanostructures is often weaker than type-I counterpart due to spatially separated electrons and holes. We model the bound-to-continuum absorption of type-II quantum rings (QRs) using a multiband source-radiation approach using the retarded Green function in the cylindrical coordinate system. The selection rules due to the circular symmetry for allowed transitions of absorption are utilized. The bound-tocontinuum absorptions of type-II GaSb coupled and uncoupled QRs embedded in GaAs matrix are compared here. The GaSb QRs act as energy barriers for electrons but potential wells for holes. For the coupled QR structure, the region sandwiched between two QRs forms a potential reservoir of quasi-bound electrons. Electrons in these states, though look like bound ones, would ultimately tunnel out of the reservoir through barriers. Multiband perfectly-matched layers are introduced to model the tunneling of quasi-bound states into open space. Resonance peaks are observed on the absorption spectra of type-II coupled QRs due to the formation of quasi-bound states in conduction bands, but no resonance exist in the uncoupled QR. The tunneling time of these metastable states can be extracted from the resonance and is in the order of ten femtoseconds. Absorption of coupled QRs is significantly enhanced as compared to that of uncoupled ones in certain spectral windows of interest. These features may improve the performance of photon detectors and photovoltaic devices based on type-II semiconductor nanostructures.

Surface Charge Transfer Doping via Transition Metal Oxides for Efficient p-Type Doping of II-VI Nanostructures.

PubMed

Xia, Feifei; Shao, Zhibin; He, Yuanyuan; Wang, Rongbin; Wu, Xiaofeng; Jiang, Tianhao; Duhm, Steffen; Zhao, Jianwei; Lee, Shuit-Tong; Jie, Jiansheng

2016-11-22

Wide band gap II-VI nanostructures are important building blocks for new-generation electronic and optoelectronic devices. However, the difficulty of realizing p-type conductivity in these materials via conventional doping methods has severely handicapped the fabrication of p-n homojunctions and complementary circuits, which are the fundamental components for high-performance devices. Herein, by using first-principles density functional theory calculations, we demonstrated a simple yet efficient way to achieve controlled p-type doping on II-VI nanostructures via surface charge transfer doping (SCTD) using high work function transition metal oxides such as MoO 3 , WO 3 , CrO 3 , and V 2 O 5 as dopants. Our calculations revealed that these oxides were capable of drawing electrons from II-VI nanostructures, leading to accumulation of positive charges (holes injection) in the II-VI nanostructures. As a result, Fermi levels of the II-VI nanostructures were shifted toward the valence band regions after surface modifications, along with the large enhancement of work functions. In situ ultraviolet photoelectron spectroscopy and X-ray photoelectron spectroscopy characterizations verified the significant interfacial charge transfer between II-VI nanostructures and surface dopants. Both theoretical calculations and electrical transfer measurements on the II-VI nanostructure-based field-effect transistors clearly showed the p-type conductivity of the nanostructures after surface modifications. Strikingly, II-VI nanowires could undergo semiconductor-to-metal transition by further increasing the SCTD level. SCTD offers the possibility to create a variety of electronic and optoelectronic devices from the II-VI nanostructures via realization of complementary doping.

HERSCHEL GALACTIC PLANE SURVEY OF [N ii] FINE STRUCTURE EMISSION

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

Goldsmith, Paul F.; Yıldız, Umut A.; Langer, William D.

2015-12-01

We present the first large-scale high angular resolution survey of ionized nitrogen in the Galactic Plane through emission of its two fine structure transitions ([N ii]) at 122 and 205 μm. The observations were largely obtained with the PACS instrument onboard the Herschel Space Observatory. The lines of sight were in the Galactic plane, following those of the Herschel OTKP project GOT C+. Both lines are reliably detected at the 10{sup −8}–10{sup −7} Wm{sup −2} sr{sup −1} level over the range –60° ≤ l ≤ 60°. The rms of the intensity among the 25 PACS spaxels of a given pointingmore » is typically less than one third of the mean intensity, showing that the emission is extended. [N ii] is produced in gas in which hydrogen is ionized, and collisional excitation is by electrons. The ratio of the two fine structure transitions provides a direct measurement of the electron density, yielding n(e) largely in the range 10–50 cm{sup −3} with an average value of 29 cm{sup −3} and N{sup +} column densities 10{sup 16}–10{sup 17} cm{sup −2}. [N ii] emission is highly correlated with that of [C ii], and we calculate that between 1/3 and 1/2 of the [C ii] emission is associated with the ionized gas. The relatively high electron densities indicate that the source of the [N ii] emission is not the warm ionized medium (WIM), which has electron densities more than 100 times smaller. Possible origins of the observed [N ii] include the ionized surfaces of dense atomic and molecular clouds, the extended low-density envelopes of H ii regions, and low-filling factor high-density fluctuations of the WIM.« less

Detector Developments for the High Luminosity LHC Era (2/4)

ScienceCinema

Straessner, Arno

2018-04-16

Calorimetry and Muon Spectromers - Part II: When upgrading the LHC to higher luminosities, the detector and trigger performance shall be preserved - if not improved - with respect to the nominal performance. The ongoing R&D; for new radiation tolerant front-end electronics for calorimeters with higher read-out bandwidth are summarized and new possibilities for the trigger systems are presented. Similar developments are foreseen for the muon spectrometers, where also radiation tolerance of the muon detectors and functioning at high background rates is important. The corresponding plans and research work for the calorimeter and muon detectors at a LHC with highest luminsity are presented.

IEEE (Institute of Electrical and Electronics Engineers) International Pulsed Power Conference on (2nd) Held in Lubbock, Texas on 12-14 June 1979 (Digest of Technical Papers)

DTIC Science & Technology

1980-02-01

PHOTOGRAPH THIS SHEET 0 FILE P.IwLEVEL IVETRY U- AFP65,f-7YA ga- - II IDS DTIBUTION T ATEMNT A App.-ove~d for public release; Di.-tribuilon Unlinitod... PHOTOGRAPH THIS SHEET AND RETURN TO DTIC-FDAC DTIC FORM 70A DOCUMENT PROCESSING SHEET PREVIOUS EDITION MAY BE USED UNTIL MAR 86 STOCK IS EXHAUSTED. IEEE 2rd...Kolm devel- transfers momencum from a massive ch..ically diven oped the "mass driver" as part of two NASA -AMES sum- armacure to a much lighter, hi h r

40 CFR Appendix II to Part 1042 - Steady-State Duty Cycles

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Steady-State Duty Cycles II Appendix..., App. II Appendix II to Part 1042—Steady-State Duty Cycles (a) The following duty cycles apply as specified in § 1042.505(b)(1): (1) The following duty cycle applies for discrete-mode testing: E3 mode No...

40 CFR Table 2 to Subpart II of... - Volatile Organic HAP (VOHAP) Limits for Marine Coatings

Code of Federal Regulations, 2013 CFR

2013-07-01

... for Marine Coatings 2 Table 2 to Subpart II of Part 63 Protection of Environment ENVIRONMENTAL... (Surface Coating) Pt. 63, Subpt. II, Table 2 Table 2 to Subpart II of Part 63—Volatile Organic HAP (VOHAP) Limits for Marine Coatings Coating category VOHAP limits a,b,c Grams/liter coating (minus water and...

40 CFR Table 2 to Subpart II of... - Volatile Organic HAP (VOHAP) Limits for Marine Coatings

Code of Federal Regulations, 2012 CFR

2012-07-01

... for Marine Coatings 2 Table 2 to Subpart II of Part 63 Protection of Environment ENVIRONMENTAL... (Surface Coating) Pt. 63, Subpt. II, Table 2 Table 2 to Subpart II of Part 63—Volatile Organic HAP (VOHAP) Limits for Marine Coatings Coating category VOHAP limits a,b,c Grams/liter coating (minus water and...

40 CFR Table 2 to Subpart II of... - Volatile Organic HAP (VOHAP) Limits for Marine Coatings

Code of Federal Regulations, 2014 CFR

2014-07-01

... for Marine Coatings 2 Table 2 to Subpart II of Part 63 Protection of Environment ENVIRONMENTAL... (Surface Coating) Pt. 63, Subpt. II, Table 2 Table 2 to Subpart II of Part 63—Volatile Organic HAP (VOHAP) Limits for Marine Coatings Coating category VOHAP limits a b c Grams/liter coating (minus water and...

40 CFR Table 2 to Subpart II of... - Volatile Organic HAP (VOHAP) Limits for Marine Coatings

Code of Federal Regulations, 2010 CFR

2010-07-01

... for Marine Coatings 2 Table 2 to Subpart II of Part 63 Protection of Environment ENVIRONMENTAL... (Surface Coating) Pt. 63, Subpt. II, Table 2 Table 2 to Subpart II of Part 63—Volatile Organic HAP (VOHAP) Limits for Marine Coatings Coating category VOHAP limits a,b,c Grams/liter coating (minus water and...

40 CFR Table 2 to Subpart II of... - Volatile Organic HAP (VOHAP) Limits for Marine Coatings

Code of Federal Regulations, 2011 CFR

2011-07-01

... for Marine Coatings 2 Table 2 to Subpart II of Part 63 Protection of Environment ENVIRONMENTAL... (Surface Coating) Pt. 63, Subpt. II, Table 2 Table 2 to Subpart II of Part 63—Volatile Organic HAP (VOHAP) Limits for Marine Coatings Coating category VOHAP limits a,b,c Grams/liter coating (minus water and...

The second Cu(II)-binding site in a proton-rich environment interferes with the aggregation of amyloid-beta(1-40) into amyloid fibrils.

PubMed

Jun, Sangmi; Gillespie, Joel R; Shin, Byong-kyu; Saxena, Sunil

2009-11-17

The overall morphology and Cu(II) ion coordination for the aggregated amyloid-beta(1-40) [Abeta(1-40)] in N-ethylmorpholine (NEM) buffer are affected by Cu(II) ion concentration. This effect is investigated by transmission electron microscopy (TEM), atomic force microscopy (AFM), and electron spin echo envelope modulation (ESEEM) spectroscopy. At lower than equimolar concentrations of Cu(II) ions, fibrillar aggregates of Abeta(1-40) are observed. At these concentrations of Cu(II), the monomeric and fibrillar Abeta(1-40) ESEEM data indicate that the Cu(II) ion is coordinated by histidine residues. For aggregated Abeta(1-40) at a Cu(II):Abeta molar ratio of 2:1, TEM and AFM images show both linear fibrils and granular amorphous aggregates. The ESEEM spectra show that the multi-histidine coordination for Cu(II) ion partially breaks up and becomes exposed to water or exchangeable protons of the peptide at a higher Cu(II) concentration. Since the continuous-wave electron spin resonance results also suggest two copper-binding sites in Abeta(1-40), the proton ESEEM peak may arise from the second copper-binding site, which may be significantly involved in the formation of granular amorphous aggregates. Thioflavin T fluorescence and circular dichroism experiments also show that Cu(II) inhibits the formation of fibrils and induces a nonfibrillar beta-sheet conformation. Therefore, we propose that Abeta(1-40) has a second copper-binding site in a proton-rich environment and the second binding Cu(II) ion interferes with a conformational transition into amyloid fibrils, inducing the formation of granular amorphous aggregates.

Fourier transform infrared difference and time-resolved infrared detection of the electron and proton transfer dynamics in photosynthetic water oxidation.

PubMed

Noguchi, Takumi

2015-01-01

Photosynthetic water oxidation, which provides the electrons necessary for CO₂ reduction and releases O₂ and protons, is performed at the Mn₄CaO₅ cluster in photosystem II (PSII). In this review, studies that assessed the mechanism of water oxidation using infrared spectroscopy are summarized focusing on electron and proton transfer dynamics. Structural changes in proteins and water molecules between intermediates known as Si states (i=0-3) were detected using flash-induced Fourier transform infrared (FTIR) difference spectroscopy. Electron flow in PSII and proton release from substrate water were monitored using the infrared changes in ferricyanide as an exogenous electron acceptor and Mes buffer as a proton acceptor. Time-resolved infrared (TRIR) spectroscopy provided information on the dynamics of proton-coupled electron transfer during the S-state transitions. In particular, a drastic proton movement during the lag phase (~200μs) before electron transfer in the S3→S0 transition was detected directly by monitoring the infrared absorption of a polarizable proton in a hydrogen bond network. Furthermore, the proton release pathways in the PSII proteins were analyzed by FTIR difference measurements in combination with site-directed mutagenesis, isotopic substitutions, and quantum chemical calculations. Therefore, infrared spectroscopy is a powerful tool for understanding the molecular mechanism of photosynthetic water oxidation. This article is part of a Special Issue entitled: Vibrational spectroscopies and bioenergetic systems. Copyright © 2014 Elsevier B.V. All rights reserved.

31 CFR Appendix II to Part 13 - Form of Bill for Reimbursement

Code of Federal Regulations, 2010 CFR

2010-07-01

... title) of ______ (Country) to participate in the work of ______ (International Organization) or occurring at the _______ (Permanent or observer mission) to ______ (International organization) during the.... II Appendix II to Part 13—Form of Bill for Reimbursement I hereby request that ______ (Governmental...

Fate of nuclear material during subsequent steps of the kinetin-induced PCD in apical parts of Vicia faba ssp. minor seedling roots.

PubMed

Kaźmierczak, Andrzej; Soboska, Kamila

2018-07-01

In animals during apoptosis, the best examined type of programmed cell death (PCD), three main phases are distinguished: (i) specification (signaling), (ii) killing and (iii) execution one. It has bean postulated that plant PCD also involves three subsequent phases: (i) transmission of death signals to cells (signaling), (ii) initiation of killing processes and (iii) destruction of cells. One of the most important hallmarks of animal and plant PCD are those regarding nucleus, not thoroughly studied in plants so far. To study kinetin-induced PCD (Kin-PCD) in the context of nuclear material faith, 2-cm apical parts of Vicia faba ssp. minor seedling roots were used. Applied assays involving spectrophotometry, transmission electron microscopy, fluorescence and white light microscopy allowed to examine metabolic and cytomorphologic hallmarks such as changes in DNA content, ssDNA formation and activity of acidic and basic nucleases (DNases and RNases) as well as malformations and fragmentation of nucleoli and nuclei. The obtained results concerning the PCD hallmarks and influence of ZnSO 4 on Kin-PCD allowed us to confirmed presence of specification/signaling, killing and execution/degradation phases of the process and broaden the knowledge about processes affecting nuclei during PCD. Copyright © 2018 Elsevier Ltd. All rights reserved.

Association Between National Board Dental Examination Part II Scores and Comprehensive Examinations at Harvard School of Dental Medicine.

PubMed

Lee, Min Kyeong; Allareddy, Veerasathpurush; Howell, T Howard; Karimbux, Nadeem Y

2011-01-01

Harvard School of Dental Medicine (HSDM) uses a hybrid problem-based approach to teaching in the predoctoral program. The objective structured clinical examination (OSCE) is a formative examination designed to assess the performance of students in the problem-based learning (PBL) curriculum. At HSDM three comprehensive examinations with OSCE components are administered during the third and fourth years of clinical training. The National Board Dental Examination (NBDE) Part II is taken in the final year of the predoctoral program. This study examines the association between the NBDE Part II and the comprehensive exams held at HSDM. Predoctoral students from the HSDM classes of 2005 and 2006 were included in this study. The outcome variable of interest was the scores obtained by students in the NBDE Part II, and the main independent variable of interest was the performance of students in the comprehensive exams (honors, pass, make-up exam to pass). The Mann-Whitney U-test was used to examine the association between the grades obtained in the each of the three comprehensive exams and the NBDE Part II scores. Multivariable linear regression analysis was also used to examine the association between the NBDE Part II scores and the comprehensive exam grades. The effect of potential confounding factors including age, sex, and race/ethnicity was adjusted. The results suggest that students who performed well in the comprehensive exams performed better on the NBDE Part II, even after adjusting for confounding factors. Future studies will examine the long-term impact of PBL on postdoctoral plans and career choices.

48 CFR 231.205-71 - Cost of remedy for use or inclusion of counterfeit electronic parts and suspect counterfeit...

Code of Federal Regulations, 2014 CFR

2014-10-01

... inclusion of counterfeit electronic parts and suspect counterfeit electronic parts. 231.205-71 Section 231... Organizations 231.205-71 Cost of remedy for use or inclusion of counterfeit electronic parts and suspect... remedy the use or inclusion of such parts are unallowable, unless— (1) The contractor has an operational...

Self-accommodation of B19' martensite in Ti-Ni shape memory alloys - Part II. Characteristic interface structures between habit plane variants

NASA Astrophysics Data System (ADS)

Nishida, M.; Okunishi, E.; Nishiura, T.; Kawano, H.; Inamura, T.; S., Ii; Hara, T.

2012-06-01

Four characteristic interface microstructures between habit plane variants (HPVs) in the self-accommodation morphologies of B19‧ martensite in Ti-Ni alloys have been investigated by scanning transmission electron microscopy (STEM). The straight interface of a ? B19‧ type I twin is present at interface I. The relaxation of the transformation strain at interface II is achieved by a volume reduction of the minor correspondence variants (CVs) in the relevant habit plane variants (HPVs). The relaxation of the transformation strain at interface III is mainly due to the formation of a ? B19‧ type I twin between the two major CVs. Subsequently, local strain around the tips of the minor CVs perpendicular to the interface is released by the formation of micro-twins with the ⟨011⟩B19‧ type II and/or ? B19‧ type I relation. The major and minor CVs in each HPV are alternately connected through fine variants with the ? B19‧ type I twin relation parallel to interface IV. The results are compared with macroscopic observations and the predictions of PTMC analysis.

From chemolithoautotrophs to electrolithoautotrophs: CO2 fixation by Fe(II)-oxidizing bacteria coupled with direct uptake of electrons from solid electron sources.

PubMed

Ishii, Takumi; Kawaichi, Satoshi; Nakagawa, Hirotaka; Hashimoto, Kazuhito; Nakamura, Ryuhei

2015-01-01

At deep-sea vent systems, hydrothermal emissions rich in reductive chemicals replace solar energy as fuels to support microbial carbon assimilation. Until recently, all the microbial components at vent systems have been assumed to be fostered by the primary production of chemolithoautotrophs; however, both the laboratory and on-site studies demonstrated electrical current generation at vent systems and have suggested that a portion of microbial carbon assimilation is stimulated by the direct uptake of electrons from electrically conductive minerals. Here we show that chemolithoautotrophic Fe(II)-oxidizing bacterium, Acidithiobacillus ferrooxidans, switches the electron source for carbon assimilation from diffusible Fe(2+) ions to an electrode under the condition that electrical current is the only source of energy and electrons. Site-specific marking of a cytochrome aa3 complex (aa3 complex) and a cytochrome bc1 complex (bc1 complex) in viable cells demonstrated that the electrons taken directly from an electrode are used for O2 reduction via a down-hill pathway, which generates proton motive force that is used for pushing the electrons to NAD(+) through a bc1 complex. Activation of carbon dioxide fixation by a direct electron uptake was also confirmed by the clear potential dependency of cell growth. These results reveal a previously unknown bioenergetic versatility of Fe(II)-oxidizing bacteria to use solid electron sources and will help with understanding carbon assimilation of microbial components living in electronically conductive chimney habitats.

From chemolithoautotrophs to electrolithoautotrophs: CO2 fixation by Fe(II)-oxidizing bacteria coupled with direct uptake of electrons from solid electron sources

PubMed Central

Ishii, Takumi; Kawaichi, Satoshi; Nakagawa, Hirotaka; Hashimoto, Kazuhito; Nakamura, Ryuhei

2015-01-01

At deep-sea vent systems, hydrothermal emissions rich in reductive chemicals replace solar energy as fuels to support microbial carbon assimilation. Until recently, all the microbial components at vent systems have been assumed to be fostered by the primary production of chemolithoautotrophs; however, both the laboratory and on-site studies demonstrated electrical current generation at vent systems and have suggested that a portion of microbial carbon assimilation is stimulated by the direct uptake of electrons from electrically conductive minerals. Here we show that chemolithoautotrophic Fe(II)-oxidizing bacterium, Acidithiobacillus ferrooxidans, switches the electron source for carbon assimilation from diffusible Fe2+ ions to an electrode under the condition that electrical current is the only source of energy and electrons. Site-specific marking of a cytochrome aa3 complex (aa3 complex) and a cytochrome bc1 complex (bc1 complex) in viable cells demonstrated that the electrons taken directly from an electrode are used for O2 reduction via a down-hill pathway, which generates proton motive force that is used for pushing the electrons to NAD+ through a bc1 complex. Activation of carbon dioxide fixation by a direct electron uptake was also confirmed by the clear potential dependency of cell growth. These results reveal a previously unknown bioenergetic versatility of Fe(II)-oxidizing bacteria to use solid electron sources and will help with understanding carbon assimilation of microbial components living in electronically conductive chimney habitats. PMID:26500609

Commissioning and Early Operation Experience of the NSLS-II Storage Ring RF System

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

Gao, F.; Rose, J.; Cupolo, J.

2015-05-03

The National Synchrotron Light Source II (NSLS-II) is a 3 GeV electron X-ray user facility commissioned in 2014. The storage ring RF system, essential for replenishing energy loss per turn of the electrons, consists of digital low level RF controllers, 310 kW CW klystron transmitters, CESR-B type superconducting cavities, as well as a supporting cryogenic system. Here we will report on RF commissioning and early operation experience of the system for beam current up to 200mA.

Electron heat transport comparison in the Large Helical Device and TJ-II

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

Garcia, J.; Dies, J.; Castejon, F.

2007-10-15

The electron heat transport in the Large Helical Device (LHD) [K. Ida, T. Shimozuma, H. Funaba et al., Phys. Rev. Lett. 91, 085003 (2003)] and TJ-II [F. Castejon, V. Tribaldos, I. Garcia-Cortes, E. de la Luna, J. Herranz, I. Pastor, T. Estrada, and TJ-II Team, Nucl. Fusion 42, 271 (2002)] is analyzed by means of the TOTAL [K. Yamazaki and T. Amano, Nucl. Fusion 32, 4 (1992)] and PRETOR-Stellarator [J. Dies, F. Castejon, J. M. Fontdecaba, J. Fontanet, J. Izquierdo, G. Cortes, and C. Alejaldre, Proceedings of the 29th European Physical Society Conference on Plasma Physics and Controlled Fusion, Montreux,more » 2002, Europhysics Conference Abstracts, 2004, Vol. 26B, P-5.027] plasma simulation codes and assuming a global transport model mixing GyroBohm-like drift wave model and other drift wave model with shorter wavelength. The stabilization of the GyroBohm-like model by the ExB shear has been also taken into account. Results show how such kind of electron heat transport can simulate experimental evidence in both devices, leading to the electron internal transport barrier (eITB) formation in the LHD and to the so-called 'enhanced heat confinement regimes' in TJ-II when electron density is low enough. Therefore, two sources for the anomalous electron heat transport can coexist in plasmas with eITB; however, for each device the relative importance of anomalous and neoclassical transport can be different.« less

A Study of Mandarin Loanwords: Lexical Stratification, Adaptation and Factors

ERIC Educational Resources Information Center

Kim, Tae Eun

2012-01-01

This dissertation is about Chinese loanwords. It is mainly divided into two parts. Part I is a general discussion about loanwords in Chinese; Chapter I and II belong to the first part. Part II is a discussion about the analyses of Mandarin loanwords originating from English. Chapter III, IV, and V are all related to the second part. Chapter VI is…

Network Centric Operations (NCO) Case Study. The British Approach to Low-Intensity Operations: Part 2

DTIC Science & Technology

2007-02-12

Imperial War Museum Sound Archive, Accession No. 16397 (6 January 1996 ) 46 Jackson, p .45 47 Nagl, p .66-7 48 Stubbs, p .71 49 Nagl, p .93 Part II 16...Coogan, The Troubles, (London: Arrow, 1996 ), p .145 Part II 61 of 246 but there really appeared to be nothing in between to provide workable...Psychological Ops Capability Since 1945’, British Army Review, December 1996 , p .5 Part II 62 of 246 weakness caused by the lack of both numbers and

20 CFR 408.101 - What is this part about?

Code of Federal Regulations, 2011 CFR

2011-04-01

....101 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II... (Special Benefits for Certain World War II Veterans) established a program for the payment of benefits to certain World War II veterans. The regulations in this part are divided into the following subparts...

20 CFR 408.101 - What is this part about?

Code of Federal Regulations, 2014 CFR

2014-04-01

....101 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II... (Special Benefits for Certain World War II Veterans) established a program for the payment of benefits to certain World War II veterans. The regulations in this part are divided into the following subparts...

20 CFR 408.101 - What is this part about?

Code of Federal Regulations, 2013 CFR

2013-04-01

....101 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II... (Special Benefits for Certain World War II Veterans) established a program for the payment of benefits to certain World War II veterans. The regulations in this part are divided into the following subparts...

20 CFR 408.101 - What is this part about?

Code of Federal Regulations, 2012 CFR

2012-04-01

....101 Employees' Benefits SOCIAL SECURITY ADMINISTRATION SPECIAL BENEFITS FOR CERTAIN WORLD WAR II... (Special Benefits for Certain World War II Veterans) established a program for the payment of benefits to certain World War II veterans. The regulations in this part are divided into the following subparts...

Induction generators for Wind Energy Conversion Systems. Part I: review of induction generator with squirrel cage rotor. Part II: the Double Output Induction Generator (DOIG). Progress report, July-December 1975

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

Jayadev, T.S.

1976-02-01

The application of induction generators in Wind Energy Conversion Systems (WECS) is described. The conventional induction generator, which is an induction machine with a squirrel cage rotor, had been used in large wind power plants in Europe, but has not caught much attention until now by designers of large systems in this country. The induction generator with a squirrel cage rotor is described and useful design techniques to build induction generators for wind energy application are outlined. The Double Output Induction Generator (DOIG) - so called because power is fed into the grid from the stator, as well as themore » rotor is described. It is a wound rotor induction machine with power electronics to convert rotor slip frequency power to that of line frequency.« less

Optical and Electronic NO(x) Sensors for Applications in Mechatronics.

PubMed

Di Franco, Cinzia; Elia, Angela; Spagnolo, Vincenzo; Scamarcio, Gaetano; Lugarà, Pietro Mario; Ieva, Eliana; Cioffi, Nicola; Torsi, Luisa; Bruno, Giovanni; Losurdo, Maria; Garcia, Michael A; Wolter, Scott D; Brown, April; Ricco, Mario

2009-01-01

Current production and emerging NO(x) sensors based on optical and nanomaterials technologies are reviewed. In view of their potential applications in mechatronics, we compared the performance of: i) Quantum cascade lasers (QCL) based photoacoustic (PA) systems; ii) gold nanoparticles as catalytically active materials in field-effect transistor (FET) sensors, and iii) functionalized III-V semiconductor based devices. QCL-based PA sensors for NO(x) show a detection limit in the sub part-per-million range and are characterized by high selectivity and compact set-up. Electrochemically synthesized gold-nanoparticle FET sensors are able to monitor NO(x) in a concentration range from 50 to 200 parts per million and are suitable for miniaturization. Porphyrin-functionalized III-V semiconductor materials can be used for the fabrication of a reliable NO(x) sensor platform characterized by high conductivity, corrosion resistance, and strong surface state coupling.

JPL preferred parts list: Reliable electronic components

NASA Technical Reports Server (NTRS)

Covey, R. E.; Scott, W. R.; Hess, L. M.; Steffy, T. G.; Stott, F. R.

1982-01-01

The JPL Preferred Parts List was prepared to provide a basis for selection of electronic parts for JPL spacecraft programs. Supporting tests for the listed parts were designed to comply with specific spacecraft environmental requirements. The list tabulates the electronic, magnetic, and electromechanical parts applicable to all JPL electronic equipment wherein reliability is a major concern. The parts listed are revelant to equipment supplied by subcontractors as well as fabricated at the laboratory.

Functionalization of a nanostructured hydroxyapatite with Cu(II) compounds as a pesticide: in situ transmission electron microscopy and environmental scanning electron microscopy observations of treated Vitis vinifera L. leaves.

PubMed

Battiston, Enrico; Salvatici, Maria C; Lavacchi, Alessandro; Gatti, Antonietta; Di Marco, Stefano; Mugnai, Laura

2018-02-19

The present study evaluated a biocompatible material for plant protection with the aim of reducing the amount of active substance applied. We used a synthetic hydroxyapatite (HA) that has been studied extensively as a consequence of its bioactivity and biocompatibility. An aggregation between HA nanoparticles and four Cu(II) compounds applied to Vitis vinifera L. leaves as a pesticide was studied. Formulations were characterized by X-ray diffraction (XRD), dynamic light scattering (DLS) and electron microscopy and applied in planta to verify particle aggregation and efficiency in controlling the pathogen Plasmopara viticola. The XRD patterns showed different crystalline phases dependig on the Cu(II) compound formulated with HA particles, DLS showed that nanostructured particles are stable as aggregates out of the nanometer range and, in all formulations, transmission electron microscopy (TEM) and environmental scanning electron microscopy (ESEM) microscopy showed large aggregates which were partially nanostructured and were recognized as stable in their micrometric dimensions. Such particles did not show phytotoxic effects after their application in planta. A formulation based on HA and a soluble Cu(II) compound showed promising results in the control of the fungal pathogen, confirming the potential role of HA as an innovative delivery system of Cu(II) ions. The present work indicates the possibility of improving the biological activity of a bioactive substance by modifying its structure through an achievable formulation with a biocompatible material. © 2018 Society of Chemical Industry. © 2018 Society of Chemical Industry.

Generic tags for Mn(ii) and Gd(iii) spin labels for distance measurements in proteins.

PubMed

Yang, Yin; Gong, Yan-Jun; Litvinov, Aleksei; Liu, Hong-Kai; Yang, Feng; Su, Xun-Cheng; Goldfarb, Daniella

2017-10-11

High-affinity chelating tags for Gd(iii) and Mn(ii) ions that provide valuable high-resolution distance restraints for biomolecules were used as spin labels for double electron-electron resonance (DEER) measurements. The availability of a generic tag that can bind both metal ions and provide a narrow and predictable distance distribution for both ions is attractive owing to their different EPR-related characteristics. Herein we introduced two paramagnetic tags, 4PSPyMTA and 4PSPyNPDA, which are conjugated to cysteine residues through a stable thioether bond, forming a short and, depending on the metal ion coordination mode, a rigid tether with the protein. These tags exhibit high affinity for both Mn(ii) and Gd(iii) ions. The DEER performance of the 4PSPyMTA and 4PSPyNPDA tags, in complex with Gd(iii) or Mn(ii), was evaluated for three double cysteine mutants of ubiquitin, and the Gd(iii)-Gd(iii) and Mn(ii)-Mn(ii) distance distributions they generated were compared. All three Gd(iii) complexes of the ubiquitin-PyMTA and ubiquitin-PyNPDA conjugates produced similar and expected distance distributions. In contrast, significant variations in the maxima and widths of the distance distributions were observed for the Mn(ii) analogs. Furthermore, whereas PyNPDA-Gd(iii) and PyNPDA-Mn(ii) delivered similar distance distributions, appreciable differences were observed for two mutants with PyMTA, with the Mn(ii) analog exhibiting a broader distance distribution and shorter distances. ELDOR (electron-electron double resonance)-detected NMR measurements revealed some distribution in the Mn(ii) coordination environment for the protein conjugates of both tags but not for the free tags. The broader distance distributions generated by 4PSPyMTA-Mn(ii), as compared with Gd(iii), were attributed to the distributed location of the Mn(ii) ion within the PyMTA chelate owing to its smaller size and lower coordination number that leave the pyridine nitrogen uncoordinated. Accordingly, in terms of distance resolution, 4PSPyNPDA can serve as an effective generic tag for Gd(iii) and Mn(ii), whereas 4PSPyMTA is efficient for Gd(iii) only. This comparison between Gd(iii) and Mn(ii) suggests that PyMTA model compounds may not predict sufficiently well the performance of PyMTA-Mn(ii) as a tag for high-resolution distance measurements in proteins because the protein environment can influence its coordination mode.

Characterisation of inorganic microparticles in pigment cells of human gut associated lymphoid tissue.

PubMed Central

Powell, J J; Ainley, C C; Harvey, R S; Mason, I M; Kendall, M D; Sankey, E A; Dhillon, A P; Thompson, R P

1996-01-01

Macrophages at the base of human gut associated lymphoid tissue (GALT), become loaded early in life with dark granular pigment that is rich in aluminium, silicon, and titanium. The molecular characteristics, intracellular distribution, and source of this pigment is described. Laser scanning and electron microscopy showed that pigmented macrophages were often closely related to collagen fibres and plasma cells in GALT of both small and large intestine and contained numerous phagolysosomes, previously described as granules, that are rich in electron dense submicron sized particles. Morphological assessment, x ray microanalysis, and image electron energy loss spectroscopy showed three distinct types of microparticle: type I - spheres of titanium dioxide, 100-200 nm diameter, characterised as the synthetic food-additive polymorph anatase; type II - aluminosilicates, < 100-400 nm in length, generally of flaky appearance, often with adsorbed surface iron, and mostly characteristic of the natural clay mineral kaolinite; and type III - mixed environmental silicates without aluminium, 100-700 nm in length and of variable morphology. Thus, this cellular pigment that is partly derived from food additives and partly from the environment is composed of inert inorganic microparticles and loaded into phagolysosomes of macrophages within the GALT of all human subjects. These observations suggest that the pathogenicity of this pigment should be further investigated since, in susceptible individuals, the same intracellular distribution of these three types of submicron particle causes chronic latent granulomatous inflammation. Images Figure 1 Figure 2 Figure 3 Figure 4 Figure 5 Figure 7 PMID:8675092

Cation Effects on the Electron-Acceptor Side of Photosystem II.

PubMed

Khan, Sahr; Sun, Jennifer S; Brudvig, Gary W

2015-06-18

The normal pathway of electron transfer on the electron-acceptor side of photosystem II (PSII) involves electron transfer from quinone A, QA, to quinone B, QB. It is possible to redirect electrons from QA(-) to water-soluble Co(III) complexes, which opens a new avenue for harvesting electrons from water oxidation by immobilization of PSII on electrode surfaces. Herein, the kinetics of electron transfer from QA(-) to [Co(III)(terpy)2](3+) (terpy = 2,2';6',2″-terpyridine) are investigated with a spectrophotometric assay revealing that the reaction follows Michaelis-Menten saturation kinetics, is inhibited by cations, and is not affected by variation of the QA reduction potential. A negatively charged site on the stromal surface of the PSII protein complex, composed of glutamic acid residues near QA, is hypothesized to bind cations, especially divalent cations. The cations are proposed to tune the redox properties of QA through electrostatic interactions. These observations may thus explain the molecular basis of the effect of divalent cations like Ca(2+), Sr(2+), Mg(2+), and Zn(2+) on the redox properties of the quinones in PSII, which has previously been attributed to long-range conformational changes propagated from divalent cations binding to the Ca(II)-binding site in the oxygen-evolving complex on the lumenal side of the PSII complex.

NASA EEE Parts and NASA Electronic Parts and Packaging (NEPP) Program Update 2018

NASA Technical Reports Server (NTRS)

Label, Kenneth A.; Sampson, Michael J.; Pellish, Jonathan A.; Majewicz, Peter J.

2018-01-01

NASA Electronic Parts and Packaging (NEPP) Program and NASA Electronic Parts Assurance Group (NEPAG) are NASAs point-of-contacts for reliability and radiation tolerance of EEE parts and their packages. This presentation includes an FY18 program overview.

Domestic Production Issues in Chromium and Platinum-Group Metals

DTIC Science & Technology

1988-09-01

iridium, and minor amounts of osmium. 12 Uses. Platinum-group metals (PGM) are critical as catalysts in fossil fuel processing and electronic...metals (PGM) were then described as critical in fossil fuel production, and in electronic and electrical components. The international market is...this research process . ii Table of Contents Page Preface.. .............. ii List of Figures ................ vi List of Tables ................ vi

Rational Design of an Electron-Reservoir Pt(II) Complex for Efficient Photocatalytic Hydrogen Production from Water.

PubMed

Whang, Dong Ryeol; Park, Soo Young

2015-10-12

Herein we report a Pt(II) complex containing a 4,4'-bis[4-(triphenylsilyl)phenyl]-2,2'-bipyridine ligand as a molecular catalyst for water splitting. Systematic studies of the electrochemical and electronic properties of this catalyst, in comparison with two control complexes, reveal electron-reservoir characteristics upon two-electron reduction. A turnover number of 510,000 was recorded by employing this complex as a water reduction catalyst in combination with a state-of-the-art photosensitizer and N,N-dimethylaniline as a sacrificial electron donor, which represents a large improvement over the control complexes that do not contain the tetraphenylsilyl ligand substitution. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Type IV pili of Acidithiobacillus ferrooxidans can transfer electrons from extracellular electron donors.

PubMed

Li, Yongquan; Li, Hongyu

2014-03-01

Studies on Acidithiobacillus ferrooxidans accepting electrons from Fe(II) have previously focused on cytochrome c. However, we have discovered that, besides cytochrome c, type IV pili (Tfp) can transfer electrons. Here, we report conduction by Tfp of A. ferrooxidans analyzed with a conducting-probe atomic force microscope (AFM). The results indicate that the Tfp of A. ferrooxidans are highly conductive. The genome sequence of A. ferrooxidans ATCC 23270 contains two genes, pilV and pilW, which code for pilin domain proteins with the conserved amino acids characteristic of Tfp. Multiple alignment analysis of the PilV and PilW (pilin) proteins indicated that pilV is the adhesin gene while pilW codes for the major protein element of Tfp. The likely function of Tfp is to complete the circuit between the cell surface and Fe(II) oxides. These results indicate that Tfp of A. ferrooxidans might serve as biological nanowires transferring electrons from the surface of Fe(II) oxides to the cell surface. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

The NASA Electronic Parts and Packaging (NEPP) Program: Overview and Update FY15 and Beyond

NASA Technical Reports Server (NTRS)

LaBel, Kenneth A.; Sampson, Michael J.

2016-01-01

The NASA Electronic Parts and Packaging (NEPP) program, and its subset the NASA Electronic Parts Assurance Group (NEPAG), are NASA's point-of-contacts for reliability and radiation tolerance of electrical, electronic, and electromechanical (EEE) parts and their packages. This presentation includes a Fiscal Year 2015 program overview.

12 CFR Appendix II to Part 27 - Information for Government Monitoring Purposes

Code of Federal Regulations, 2010 CFR

2010-01-01

... II Appendix II to Part 27 Banks and Banking COMPTROLLER OF THE CURRENCY, DEPARTMENT OF THE TREASURY... Monitoring Purposes The following language is approved by the Comptroller of the Currency and will satisfy... used separately. This information may also be provided orally by the applicant. The following...

40 CFR Appendix II to Part 86 - Temperature Schedules

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 19 2014-07-01 2014-07-01 false Temperature Schedules II Appendix II... to Part 86—Temperature Schedules (a) Ambient temperature cycle for the diurnal emission portion of the evaporative emission test (see § 86.133). Table I—Temperature Versus Time Sequence Use linear...

One-electron oxidation of electronically diverse manganese(III) and nickel(II) salen complexes: transition from localized to delocalized mixed-valence ligand radicals.

PubMed

Kurahashi, Takuya; Fujii, Hiroshi

2011-06-01

Ligand radicals from salen complexes are unique mixed-valence compounds in which a phenoxyl radical is electronically linked to a remote phenolate via a neighboring redox-active metal ion, providing an opportunity to study electron transfer from a phenolate to a phenoxyl radical mediated by a redox-active metal ion as a bridge. We herein synthesize one-electron-oxidized products from electronically diverse manganese(III) salen complexes in which the locus of oxidation is shown to be ligand-centered, not metal-centered, affording manganese(III)-phenoxyl radical species. The key point in the present study is an unambiguous assignment of intervalence charge transfer bands by using nonsymmetrical salen complexes, which enables us to obtain otherwise inaccessible insight into the mixed-valence property. A d(4) high-spin manganese(III) ion forms a Robin-Day class II mixed-valence system, in which electron transfer is occurring between the localized phenoxyl radical and the phenolate. This is in clear contrast to a d(8) low-spin nickel(II) ion with the same salen ligand, which induces a delocalized radical (Robin-Day class III) over the two phenolate rings, as previously reported by others. The present findings point to a fascinating possibility that electron transfer could be drastically modulated by exchanging the metal ion that bridges the two redox centers. © 2011 American Chemical Society

25 CFR 547.1 - What is the purpose of this part?

Code of Federal Regulations, 2011 CFR

2011-04-01

... STANDARDS FOR GAMING EQUIPMENT USED WITH THE PLAY OF CLASS II GAMES § 547.1 What is the purpose of this part... other technologic aids in connection with the play of Class II games. This part establishes the minimum...

25 CFR 547.1 - What is the purpose of this part?

Code of Federal Regulations, 2010 CFR

2010-04-01

... STANDARDS FOR GAMING EQUIPMENT USED WITH THE PLAY OF CLASS II GAMES § 547.1 What is the purpose of this part... other technologic aids in connection with the play of Class II games. This part establishes the minimum...

25 CFR 547.1 - What is the purpose of this part?

Code of Federal Regulations, 2012 CFR

2012-04-01

... STANDARDS FOR GAMING EQUIPMENT USED WITH THE PLAY OF CLASS II GAMES § 547.1 What is the purpose of this part... other technologic aids in connection with the play of Class II games. This part establishes the minimum...

Prime Contract Awards Alphabetically by Contractor, by State or Country, and Place, FY 88. Part 15. (Ogilvie Electronics-Prime Engineering Co., Inc.)

DTIC Science & Technology

1988-01-01

1 MON 𔃺 cr U. WU NN U& 0 > I- I’X O 𔃺 co w A - 00 C . CL 0 0 I= 0 II ON I 0f C14 w(N 0 ~ 0 ~ N 0D zN I-- 2 -C Z ICON " 00 1-1 I4ii~iiiN 00 00 0 CO...f, r- 000000 00 00 00 00 00 0AC- 00 00 00 < ICOC’ 1 000 00 000000 000000 00 00 00 00 00 L 00 0000 00 I COON I1"-> 1’COON 1 F- 0 .I 0. LA 4C ICON 4...00 0000c00 00 0000 000000 0000 00 0000 000000 00 00 39W0 ’oq 10 40WON00 9- ICON " I .4 CIWON I90 t MON 1 1- 0 0 0 0 F.-IWO 9oi I> Z - 2 (a(00Wt0)W oLl

Making the invisible visible: improved electrospray ion formation of metalloporphyrins/-phthalocyanines by attachment of the formate anion (HCOO(-)).

PubMed

Hitzenberger, Jakob Felix; Dammann, Claudia; Lang, Nina; Lungerich, Dominik; García-Iglesias, Miguel; Bottari, Giovanni; Torres, Tomás; Jux, Norbert; Drewello, Thomas

2016-02-21

A protocol is developed for the coordination of the formate anion (HCOO(-)) to neutral metalloporphyrins (Pors) and -phthalocyanines (Pcs) containing divalent metals as a means to improve their ion formation in electrospray ionization (ESI). This method is particularly useful when the oxidation of the neutral metallomacrocycle fails. While focusing on Zn(II)Pors and Zn(II)Pcs, we show that formate is also readily attached to Mn(II), Mg(II) and Co(II)Pcs. However, for the Co(II)Pc secondary reactions can be observed. Upon collision-induced dissociation (CID), Zn(II)Por/Pc·formate supramolecular complexes can undergo the loss of CO2 in combination with transfer of a hydride anion (H(-)) to the zinc metal center. Further dissociation leads to electron transfer and hydrogen atom loss, generating a route to the radical anion of the Zn(II)Por/Pc without the need for electrochemical reduction, although the Zn(II)Por/Pc may have a too low electron affinity to allow electron transfer directly from the formate anion. In addition to single Por molecules, multi Por arrays were successfully analyzed by this method. In this case, multiple addition of formate occurs, giving rise to multiply charged species. In these multi Por arrays, complexation of the formate anion occurs by two surrounding Por units (sandwich). Therefore, the maximum attainment of formate anions in these arrays corresponds to the number of such sandwich complexes rather than the number of porphyrin moieties. The same bonding motif leads to dimers of the composition [(Zn(II)Por/Pc)2·HCOO](-). In these, the formate anion can act as a structural probe, allowing the distinction of isomeric ions with the formate bridging two macrocycles or being attached to a dimer of directly connected macrocycles.

Spectral characterization, cyclic voltammetry, morphology, biological activities and DNA cleaving studies of amino acid Schiff base metal(II) complexes

NASA Astrophysics Data System (ADS)

Neelakantan, M. A.; Rusalraj, F.; Dharmaraja, J.; Johnsonraja, S.; Jeyakumar, T.; Sankaranarayana Pillai, M.

2008-12-01

Metal complexes are synthesized with Schiff bases derived from o-phthalaldehyde (opa) and amino acids viz., glycine (gly) L-alanine (ala), L-phenylalanine (pal). Metal ions coordinate in a tetradentate or hexadentate manner with these N 2O 2 donor ligands, which are characterized by elemental analysis, molar conductance, magnetic moments, IR, electronic, 1H NMR and EPR spectral studies. The elemental analysis suggests the stoichiometry to be 1:1 (metal:ligand). Based on EPR studies, spin-Hamiltonian and bonding parameters have been calculated. The g-values calculated for copper complexes at 300 K and in frozen DMSO (77 K) indicate the presence of the unpaired electron in the d orbital. The evaluated metal-ligand bonding parameters showed strong in-plane σ- and π-bonding. X-ray diffraction (XRD) and scanning electron micrography (SEM) analysis provide the crystalline nature and the morphology of the metal complexes. The cyclic voltammograms of the Cu(II)/Mn(II)/VO(II) complexes investigated in DMSO solution exhibit metal centered electroactivity in the potential range -1.5 to +1.5 V. The electrochemical data obtained for Cu(II) complexes explains the change of structural arrangement of the ligand around Cu(II) ions. The biological activity of the complexes has been tested on eight bacteria and three fungi. Cu(II) and Ni(II) complexes show an increased activity in comparison to the controls. The metal complexes of opapal Schiff base were evaluated for their DNA cleaving activities with calf-thymus DNA (CT DNA) under aerobic conditions. Cu(II) and VO(II) complexes show more pronounced activity in presence of the oxidant.

Unified description of H-atom-induced chemicurrents and inelastic scattering.

PubMed

Kandratsenka, Alexander; Jiang, Hongyan; Dorenkamp, Yvonne; Janke, Svenja M; Kammler, Marvin; Wodtke, Alec M; Bünermann, Oliver

2018-01-23

The Born-Oppenheimer approximation (BOA) provides the foundation for virtually all computational studies of chemical binding and reactivity, and it is the justification for the widely used "balls and springs" picture of molecules. The BOA assumes that nuclei effectively stand still on the timescale of electronic motion, due to their large masses relative to electrons. This implies electrons never change their energy quantum state. When molecules react, atoms must move, meaning that electrons may become excited in violation of the BOA. Such electronic excitation is clearly seen for: ( i ) Schottky diodes where H adsorption at Ag surfaces produces electrical "chemicurrent;" ( ii ) Au-based metal-insulator-metal (MIM) devices, where chemicurrents arise from H-H surface recombination; and ( iii ) Inelastic energy transfer, where H collisions with Au surfaces show H-atom translation excites the metal's electrons. As part of this work, we report isotopically selective hydrogen/deuterium (H/D) translational inelasticity measurements in collisions with Ag and Au. Together, these experiments provide an opportunity to test new theories that simultaneously describe both nuclear and electronic motion, a standing challenge to the field. Here, we show results of a recently developed first-principles theory that quantitatively explains both inelastic scattering experiments that probe nuclear motion and chemicurrent experiments that probe electronic excitation. The theory explains the magnitude of chemicurrents on Ag Schottky diodes and resolves an apparent paradox--chemicurrents exhibit a much larger isotope effect than does H/D inelastic scattering. It also explains why, unlike Ag-based Schottky diodes, Au-based MIM devices are insensitive to H adsorption.

Synthesis and characterization of hydroxyapatite nanoparticles impregnated on apple pomace to enhanced adsorption of Pb(II), Cd(II), and Ni(II) ions from aqueous solution.

PubMed

Chand, Piar; Pakade, Yogesh B

2015-07-01

Hydroxyapatite nanoparticles were synthesized, characterized, and impregnated onto apple pomace surface (HANP@AP) for efficient removal of Pb(II), Cd(II), and Ni(II) ions from water. HANP@AP was characterized by Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), energy-dispersive spectroscopy (EDS), transmission electron microscope (TEM), X-ray diffraction (XRD), and surface area analysis. Batch sorption studies were carried out to investigate the influence of different parameters as amount of dose (g), pH, time (min), and initial concentration (mg L(-1)) on adsorption process. Experimental kinetic data followed pseudo-second-order model and equilibrium data well fitted to Langmuir adsorption model with maximum adsorption capacities of 303, 250, and 100 mg g(-1) for Pb(II), Cd(II), and Ni(II) ions, respectively. Competitive adsorption of Pb(II), Cd(II), and Ni(II) ions in presences of each other was studied to evaluate the removal efficiency of HANP@AP against multi metal-loaded water. HANP@AP was successfully applied to real industrial wastewater with 100 % removal of all three metal ions even at high concentration. HANP@AP could be recycled for four, four, and three cycles in case of Pb(II), Cd(II) and Ni(II), respectively. The study showed that HANP@AP is fast, cost effective, and environmental friendly adsorbent for removal of Pb(II), Cd(II), and Ni(II) ions from real industrial wastewater.

In Situ D-periodic Molecular Structure of Type II Collagen

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

Antipova, Olga; Orgel, Joseph P.R.O.

Collagens are essential components of extracellular matrices in multicellular animals. Fibrillar type II collagen is the most prominent component of articular cartilage and other cartilage-like tissues such as notochord. Its in situ macromolecular and packing structures have not been fully characterized, but an understanding of these attributes may help reveal mechanisms of tissue assembly and degradation (as in osteo- and rheumatoid arthritis). In some tissues such as lamprey notochord, the collagen fibrillar organization is naturally crystalline and may be studied by x-ray diffraction. We used diffraction data from native and derivative notochord tissue samples to solve the axial, D-periodic structuremore » of type II collagen via multiple isomorphous replacement. The electron density maps and heavy atom data revealed the conformation of the nonhelical telopeptides and the overall D-periodic structure of collagen type II in native tissues, data that were further supported by structure prediction and transmission electron microscopy. These results help to explain the observed differences in collagen type I and type II fibrillar architecture and indicate the collagen type II cross-link organization, which is crucial for fibrillogenesis. Transmission electron microscopy data show the close relationship between lamprey and mammalian collagen fibrils, even though the respective larger scale tissue architecture differs.« less

Quasiparticle Scattering in Type-II Weyl semimetal MoTe₂.

PubMed

Lin, Chun-Liang; Arafune, Ryuichi; Minamitani, Emi; Kawai, Maki; Takagi, Noriaki

2018-01-30

The electronic structure of type-II Weyl semimetal molybdenum ditelluride (MoTe₂) is studied by using scanning tunneling microscopy and density functional theory calculations. Through measuring energy-dependent quasiparticle interference (QPI) patterns with a cryogenic scanning tunneling microscope, several characteristic features are found in the QPI patterns. Two of them arise from the Weyl semimetal nature; one is the topological Fermi arc surface state and the other can be assigned to be a Weyl point. The remaining structures are derived from the scatterings relevant to the bulk electronic states. The findings lead to thorough understanding of the topological electronic structure of type-II Weyl semimetal MoTe₂. © 2018 IOP Publishing Ltd.

The electronic spectra and the structures of the individual copper(II) chloride and bromide complexes in acetonitrile according to steady-state absorption spectroscopy and DFT/TD-DFT calculations

NASA Astrophysics Data System (ADS)

Olshin, Pavel K.; Myasnikova, Olesya S.; Kashina, Maria V.; Gorbunov, Artem O.; Bogachev, Nikita A.; Kompanets, Viktor O.; Chekalin, Sergey V.; Pulkin, Sergey A.; Kochemirovsky, Vladimir A.; Skripkin, Mikhail Yu.; Mereshchenko, Andrey S.

2018-03-01

The results of spectrophotometric study and quantum chemical calculations for copper(II) chloro- and bromocomplexes in acetonitrile are reported. Electronic spectra of the individual copper(II) halide complexes were obtained in a wide spectral range 200-2200 nm. Stability constants of the individual copper(II) halide complexes in acetonitrile were calculated: log β1 = 8.5, log β2 = 15.6, log β3 = 22.5, log β4 = 25.7 for [CuCln]2-n and log β1 = 17.0, log β2 = 24.6, log β3 = 28.1, log β4 = 30.4 for [CuBrn]2-n. Structures of the studied complexes were optimized and electronic spectra were simulated using DFT and TD-DFT methodologies, respectively. According to the calculations, the more is the number of halide ligands the less is coordination number of copper ion.

Synthesis, characterization and investigation of electrochemical and spectroelectrochemical properties of non-peripherally tetra-5-methyl-1,3,4-thiadiazole substituted copper(II) iron(II) and oxo-titanium (IV) phthalocyanines

NASA Astrophysics Data System (ADS)

Demirbaş, Ümit; Akyüz, Duygu; Akçay, Hakkı Türker; Barut, Burak; Koca, Atıf; Kantekin, Halit

2017-09-01

In this study novel substituted phthalonitrile (3) and non-peripherally tetra 5-Methyl-1,3,4-thiadiazole substituted copper(II) (4), iron(II) (5) and oxo-titanium (IV) (6) phthalocyanines were synthesized. These novel compounds were fully characterized by FT-IR, 1H NMR, UV-vis and MALDI-TOF mass spectroscopic techniques. Voltammetric and in situ spectroelectrochemical measurements were performed for metallo-phthalocyanines (4-6). TiIVOPc and FeIIPc showed metal-based and ligand-based electron transfer reactions while CuIIPc shows only ligand-based electron transfer reaction. Voltammetric measurements indicated that the complexes have reversible, diffusion controlled and one-electron redox reactions. The assignments of the redox processes and color of the electrogenerated species of the complexes were determined with in-situ spectroelectrochemical and electrocolorimetric measurements. These measurements showed that the complexes can be used as the electrochromic materials for various display technologies.

Exposure and Emissions Monitoring during Carbon Nanofiber Production—Part I: Elemental Carbon and Iron–Soot Aerosols

PubMed Central

Birch, M. Eileen; Ku, Bon-Ki; Evans, Douglas E.; Ruda-Eberenz, Toni A.

2015-01-01

Production of carbon nanofibers and nanotubes (CNFs/CNTs) and their composite products is increasing globally. High volume production may increase the exposure risks for workers who handle these materials. Though health effects data for CNFs/CNTs are limited, some studies raise serious health concerns. Given the uncertainty about their potential hazards, there is an immediate need for toxicity data and field studies to assess exposure to CNFs/CNTs. An extensive study was conducted at a facility that manufactures and processes CNFs. Filter, sorbent, cascade impactor, bulk, and microscopy samples, combined with direct-reading instruments, provided complementary information on air contaminants. Samples were analyzed for organic carbon (OC) and elemental carbon (EC), metals, and polycyclic aromatic hydrocarbons (PAHs), with EC as a measure of CNFs. Transmission electron microscopy with energy-dispersive X-ray spectroscopy also was applied. Fine/ultrafine iron-rich soot, PAHs, and carbon monoxide were production byproducts. Direct-reading instrument results were reported previously [Evans DE et al. (Aerosol monitoring during carbon nanofiber production: mobile direct-reading sampling. Ann Occup Hyg 2010;54:514–31.)] Results for time-integrated samples are reported as companion papers in this Issue. OC and EC, metals, and microscopy results are reported here, in Part I, while results for PAHs are reported in Part II [Birch ME. (Exposure and Emissions Monitoring during Carbon Nanofiber Production—Part II: Polycyclic Aromatic Hydrocarbons. Ann. Occup. Hyg 2011; 55: 1037–47.)]. Respirable EC area concentrations inside the facility were about 6–68 times higher than outdoors, while personal breathing zone samples were up to 170 times higher. PMID:21965464

21 CFR 1305.27 - Preservation of electronic orders.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 9 2013-04-01 2013-04-01 false Preservation of electronic orders. 1305.27 Section... II CONTROLLED SUBSTANCES Electronic Orders § 1305.27 Preservation of electronic orders. (a) A... two years. (c) If electronic order records are maintained on a central server, the records must be...

21 CFR 1305.27 - Preservation of electronic orders.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 9 2012-04-01 2012-04-01 false Preservation of electronic orders. 1305.27 Section... II CONTROLLED SUBSTANCES Electronic Orders § 1305.27 Preservation of electronic orders. (a) A... two years. (c) If electronic order records are maintained on a central server, the records must be...

21 CFR 1305.27 - Preservation of electronic orders.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 9 2011-04-01 2011-04-01 false Preservation of electronic orders. 1305.27 Section... II CONTROLLED SUBSTANCES Electronic Orders § 1305.27 Preservation of electronic orders. (a) A... two years. (c) If electronic order records are maintained on a central server, the records must be...

21 CFR 1305.27 - Preservation of electronic orders.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 9 2014-04-01 2014-04-01 false Preservation of electronic orders. 1305.27 Section... II CONTROLLED SUBSTANCES Electronic Orders § 1305.27 Preservation of electronic orders. (a) A... two years. (c) If electronic order records are maintained on a central server, the records must be...

21 CFR 1305.27 - Preservation of electronic orders.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Preservation of electronic orders. 1305.27 Section... II CONTROLLED SUBSTANCES Electronic Orders § 1305.27 Preservation of electronic orders. (a) A... two years. (c) If electronic order records are maintained on a central server, the records must be...

Front-end electronics of the Belle II drift chamber

NASA Astrophysics Data System (ADS)

Shimazaki, Shoichi; Taniguchi, Takashi; Uchida, Tomohisa; Ikeno, Masahiro; Taniguchi, Nanae; Tanaka, Manobu M.

2014-01-01

This paper describes the performance of the Belle II central drift chamber (CDC) front-end electronics. The front-end electronics consists of a current sensitive preamplifier, a 1/t cancellation circuit, baseline restorers, a comparator for timing measurement and an analog buffer for the dE/dx measurement on a CDC readout card. The CDC readout card is located on the endplate of the CDC. Mass production will be completed after the performance of the chip is verified. The electrical performance and results of a neutron/gamma-ray irradiation test are reported here.

Biotic stress induced demolition of thylakoid structure and loss in photoelectron transport of chloroplasts in papaya leaves.

PubMed

Nanda, Rashmi Madhumita; Biswal, Basanti

2008-04-01

Papaya mosaic virus (PMV) causes severe mosaic symptoms in the papaya (Carica papaya L.) leaves. The PMV-induced alterations in photosystem II (PS II) structure and photochemical functions were probed. An increase in chlorophyll a (Chl a) fluorescence polarization suggests pathogen-induced transformation of thylakoid membrane to a gel phase. This transformation in physical state of thylakoid membrane may result in alteration in topology of pigments on pigment-binding proteins as reflected in pathogen-induced loss in the efficiency of energy transfer from carotenoids to chlorophylls. The fast Chl a fluorescence induction kinetics of healthy and PMV-infected plants by F(O)-F(J)-F(I)-F(P) transients revealed pathogen-induced perturbation on PS II acceptor side electron transfer equilibrium between Q(A) and Q(B) and in the pool size of electron transport acceptors. Pathogen-induced loss in photosynthetic pigments, changes in thylakoid structure and decrease in the ratio of F(V)/F(M) (photochemical potential of PS II) further correlate with the loss in photoelectron transport of PS II as probed by 2,6-dichlorophenol indophenol (DCPIP)-Hill reaction. Restoration of the loss by 1,5-diphenyl carbazide (DPC), an exogenous electron donor, that donates electron directly to reaction centre II bypassing the oxygen evolving system (OES), leads towards the conclusion that OES is one of the major targets of biotic stress. Further, the data suggest that chlorophyll fluorescence could be used as a non-invasive handy tool to assess the loss in photosynthetic efficiency and symptom severity in infected green tissues vis-a-vis the healthy ones.

New Rh 2 (II,II) Architecture for the Catalytic Reduction of H +

DOE PAGES

White, Travis A.; Witt, Suzanne E.; Li, Zhanyong; ...

2015-09-25

Formamidinate-bridged Rh 2 II,II complexes containing diimine ligands of the formula cis-[Rh 2 II,II(μ-DTolF) 2(NN) 2] 2+ (Rh 2-NN 2), where DTolF = p-ditolylformamidinate and NN = dppn (benzo[i]dipyrido[3,2-a:2',3'-h]quinoxaline), dppz (dipyrido[3,2-a:2',3'-c]phenazine), and phen (1,10-phenanthroline), electrocatalytically reduce H + to H 2 in DMF solutions containing CH 3COOH at a glassy carbon electrode. Cathodic scans in the absence of acid display a Rh III,II/II,II reduction at -0.90 V vs Fc +/Fc followed by NN 0/– reduction at -1.13, -1.36, and -1.65 V for Rh 2-dppn 2, Rh 2-dppz 2, and Rh 2-phen 2, respectively. Upon the addition of acid, Rh 2-dppnmore » 2 and Rh 2-dppz 2 undergo reduction–protonation–reduction at each pyrazine-containing NN ligand prior to the Rh 2 II,II/II,I reduction. The Rh 2 II,I species is thus protonated at one of the metal centers, resulting in the formation of the corresponding Rh 2 II,III-hydride. In the case of Rh 2-phen 2, the reduction of the phen ligand is followed by intramolecular electron transfer to the Rh 2 II,II core in the presence of protons to form a Rh 2 II,III-hydride species. Further reduction and protonation at the Rh 2 core for all three complexes rapidly catalyzes H 2 formation with varied calculated turnover frequencies (TOF) and overpotential values (η): 2.6 × 10 4 s –1 and 0.56 V for Rh 2-dppn, 2.8 × 10 4 s –1 and 0.50 V for Rh 2-dppz 2, and 5.9 × 10 4 s –1 and 0.64 V for Rh 2-phen 2. Bulk electrolysis confirmed H 2 formation, and further CH 3COOH addition regenerates H 2 production, attesting to the robust nature of the architecture. The cis-[Rh 2 II,II(μ-DTolF) 2(NN) 2] 2+ architecture benefits by combining electron-rich formamidinate bridges, a redox-active Rh 2 II,II core, and electron-accepting NN diimine ligands to allow for the electrocatalysis of H + substrate to H 2 fuel.« less

Empirical STORM-E Model. [I. Theoretical and Observational Basis

NASA Technical Reports Server (NTRS)

Mertens, Christopher J.; Xu, Xiaojing; Bilitza, Dieter; Mlynczak, Martin G.; Russell, James M., III

2013-01-01

Auroral nighttime infrared emission observed by the Sounding of the Atmosphere using Broadband Emission Radiometry (SABER) instrument onboard the Thermosphere-Ionosphere-Mesosphere Energetics and Dynamics (TIMED) satellite is used to develop an empirical model of geomagnetic storm enhancements to E-region peak electron densities. The empirical model is called STORM-E and will be incorporated into the 2012 release of the International Reference Ionosphere (IRI). The proxy for characterizing the E-region response to geomagnetic forcing is NO+(v) volume emission rates (VER) derived from the TIMED/SABER 4.3 lm channel limb radiance measurements. The storm-time response of the NO+(v) 4.3 lm VER is sensitive to auroral particle precipitation. A statistical database of storm-time to climatological quiet-time ratios of SABER-observed NO+(v) 4.3 lm VER are fit to widely available geomagnetic indices using the theoretical framework of linear impulse-response theory. The STORM-E model provides a dynamic storm-time correction factor to adjust a known quiescent E-region electron density peak concentration for geomagnetic enhancements due to auroral particle precipitation. Part II of this series describes the explicit development of the empirical storm-time correction factor for E-region peak electron densities, and shows comparisons of E-region electron densities between STORM-E predictions and incoherent scatter radar measurements. In this paper, Part I of the series, the efficacy of using SABER-derived NO+(v) VER as a proxy for the E-region response to solar-geomagnetic disturbances is presented. Furthermore, a detailed description of the algorithms and methodologies used to derive NO+(v) VER from SABER 4.3 lm limb emission measurements is given. Finally, an assessment of key uncertainties in retrieving NO+(v) VER is presented

The Argonne CDF Group

Science.gov Websites

calorimeter, Shower Max., Preshower, Crack Chambers (1979-present) Run II Upgrade: Front end electronics (QIE , Preshower electronics and DAQ Support for Level-2 electron and photon triggers (RECES and ISO) Deputy Head

Some biodiversity points and suggestions for the Myanmar Protected Area System

Treesearch

Daniel H. Henning

2007-01-01

This paper is divided into a brief background section followed by Part I: Biodiversity Points, and Part II: Suggestions that are needed for the ecological integrity of actual and potential protected areas in Myanmar. Part I consists of general and Myanmar Biodiversity Considerations, and Part II consists of the following suggestions: (l) international financial and...

Understanding Medicines: Conceptual Analysis of Nurses' Needs for Knowledge and Understanding of Pharmacology (Part I). Understanding Medicines: Extending Pharmacology Education for Dependent and Independent Prescribing (Part II).

ERIC Educational Resources Information Center

Leathard, Helen L.

2001-01-01

Part I reviews what nurses need to know about the administration and prescription of medicines. Part II addresses drug classifications, actions and effects, and interactions. Also discussed are the challenges pharmacological issues pose for nursing education. (SK)

Estimating Welfare Effects Consistent with Forward-Looking Behavior. Part I: Lessons from a Simulation Exercise. Part II: Empirical Results.

ERIC Educational Resources Information Center

Keane, Michael P.; Wolpin, Kenneth I.

2002-01-01

Part I uses simulations of a model of welfare participation and women's fertility decisions, showing that increases in per-child payments have substantial impact on fertility. Part II uses estimations of decision rules of forward-looking women regarding welfare participation, fertility, marriage, work, and schooling. (SK)

78 FR 24061 - Minimum Technical Standards for Class II Gaming Systems and Equipment

Federal Register 2010, 2011, 2012, 2013, 2014

2013-04-24

... Register that established technical standards for ensuring the integrity of electronic Class II games and aids. 73 FR 60508, Oct. 10, 2008. The technical standards were designed to assist tribal gaming... Class II gaming systems. The standards did not classify which games were Class II games and which games...

TRANSFORMATION OF NITROSOBENZENES AND HYDROXYLANILINES BY FE II SPECIES: ELUCIDATION OF MECHANISM, EFFECT OF FERRIC OXIDES AND PH

EPA Science Inventory

Nitrosobenzenes, the first intermediates in the reduction of nitrobenzenes, were reduced by Fe(II) solutions as well as by Fe(II)-treated goethite suspensions (Fe(II)/G). Results indicate a reactivity trend in which electron-withdrawing groups in the para position increased the ...

NASA Electronic Parts and Packaging Program

NASA Technical Reports Server (NTRS)

Kayali, Sammy

2000-01-01

NEPP program objectives are to: (1) Access the reliability of newly available electronic parts and packaging technologies for usage on NASA projects through validations, assessments, and characterizations, and the development of test methods/tools; (2)Expedite infusion paths for advanced (emerging) electronic parts and packaging technologies by evaluations of readiness for manufacturability and project usage consideration; (3) Provide NASA projects with technology selection, application, and validation guidelines for electronic parts and packaging hardware and processes; nd (4) Retain and disseminate electronic parts and packaging quality assurance, reliability validations, tools, and availability information to the NASA community.

Revisiting the radial abundance gradients of nitrogen and oxygen of the Milky Way

NASA Astrophysics Data System (ADS)

Esteban, C.; García-Rojas, J.

2018-05-01

We present spectra obtained with the 10.4 m Gran Telescopio Canarias telescope of 13 Galactic H II regions, most of them of very low ionisation degree. The objects are located along the Galactic disc, with RG from 5.7 to 16.1 kpc. We determine Te([N II]) for all of them. We obtain - for the first time - a radial abundance gradient of N that is independent on the ionisation correction factor. The radial distribution of the N/O ratio is almost flat, indicating that the bulk of N is not formed by standard secondary processes. We have made a reassessment of the radial O abundance gradient combining our results with previous similar ones by Esteban et al. (2017); producing a homogeneous dataset of 35 H II regions with direct determinations of the electron temperature. We report the possible presence of a flattening or drop of the O abundance in the inner part of the Galactic disc. This result confirms previous findings from metallicity distributions based on Cepheids and red giants. Finally, we find that the scatter of the N and O abundances of H II regions with respect to the gradient fittings is not substantially larger than the observational uncertainties, indicating that both chemical elements seem to be well mixed in the interstellar gas at a given distance along the Galactic disc

Reactivity of substituted benzotrichlorides toward granular iron, Cr(II), and an iron(II) porphyrin: A correlation analysis.

PubMed

Kohn, Tamar; Arnold, William A; Roberts, A Lynn

2006-07-01

Cross-correlations of rate constants between a system of interest and a better-defined one have become popular as a tool in studying transformations of organic pollutants. A slope of unity (if the correlation is conducted on a log-log basis) in such plots has been invoked as evidence of a common mechanism. To explore this notion, benzotrichloride and several of its substituted analogues were reacted with Cr(H2O)6(2+), an iron(II) porphyrin (iron meso-tetra(4-carboxyphenyl)porphine chloride, Fe(II)TCP), and granular iron. The first two reductants react with organohalides by dissociative inner sphere single-electron transfer, while mechanism(s) for organohalide reduction by granular iron are still debated. Apartfrom sterically hindered compounds, good correlations were obtained in comparing any two systems, although slopes (on a log-log basis) deviated from unity. We argue that a slope of unity is neither necessary nor sufficient evidence of a common mechanism. Overall rate constants may be composite entities, consisting in part of rate or equilibrium constants for adsorption onto surfaces or for precursor formation in solution; these components may differ between systems in their susceptibility to substituent effects. Cross-correlations may prove useful in predicting reactivity in the absence of steric effects, but additional evidence is required in deducing reaction mechanisms.

Multiple regression analysis to assess the role of plankton on the distribution and speciation of mercury in water of a contaminated lagoon.

PubMed

Stoichev, T; Tessier, E; Amouroux, D; Almeida, C M; Basto, M C P; Vasconcelos, V M

2016-11-15

Spatial and seasonal variation of mercury species aqueous concentrations and distributions was carried out during six sampling campaigns at four locations within Laranjo Bay, the most mercury-contaminated area of the Aveiro Lagoon (Portugal). Inorganic mercury (IHg(II)) and methylmercury (MeHg) were determined in filter-retained (IHgPART, MeHgPART) and filtered (<0.45μm) fractions (IHg(II)DISS, MeHgDISS). The concentrations of IHgPART depended on site and on dilution with downstream particles. Similar processes were evidenced for MeHgPART, however, its concentrations increased for particles rich in phaeophytin (Pha). The concentrations of MeHgDISS, and especially those of IHg(II)DISS, increased with Pha concentrations in the water. Multiple regression models are able to depict MeHgPART, IHg(II)DISS and MeHgDISS concentrations with salinity and Pha concentrations exhibiting additive statistical effects and allowing separation of possible addition and removal processes. A link between phytoplankton/algae and consumers' grazing pressure in the contaminated area can be involved to increase concentrations of IHg(II)DISS and MeHgPART. These processes could lead to suspended particles enriched with MeHg and to the enhancement of IHg(II) and MeHg availability in surface waters and higher transfer to the food web. Copyright © 2016 Elsevier B.V. All rights reserved.

Electrochemical studies of DNA interaction and antimicrobial activities of MnII, FeIII, CoII and NiII Schiff base tetraazamacrocyclic complexes

NASA Astrophysics Data System (ADS)

Kumar, Anuj; Vashistha, Vinod Kumar; Tevatia, Prashant; Singh, Randhir

2017-04-01

Tetraazamacrocyclic complexes of MnII, FeIII, CoII and NiII have been synthesized by template method. These tetraazamacrocycles have been analyzed with various techniques like molar conductance, IR, UV-vis, mass spectral and cyclic voltammetric studies. On the basis of all these studies, octahedral geometry has been assigned to these tetraazamacrocyclic complexes. The DNA binding properties of these macrocyclic complexes have been investigated by electronic absorption spectra, fluorescence spectra, cyclic voltammetric and differential pulse voltammetric studies. The cyclic voltammetric data showed that ipc and ipa were effectively decreased in the presence of calf thymus DNA, which is a strong evidence for the interaction of these macrocyclic complexes with the calf thymus DNA (ct-DNA). The heterogeneous electron transfer rate constant found in the order: KCoII > KNiII > KMnII which indicates that CoII macrocyclic complex has formed a strong intercalated intermediate. The Stern-Volmer quenching constant (KSV) and voltammetric binding constant were found in the order KSV(CoII) > KSV(NiII) > KSV(MnII) and K+(CoII) > K+(NiII) > K+(MnII) which shows that CoII macrocyclic complex exhibits the high interaction affinity towards ct-DNA by the intercalation binding. Biological studies of the macrocyclic complexes compared with the standard drug like Gentamycin, have shown antibacterial activities against E. coli, P. aeruginosa, B. cereus, S. aureus and antifungal activity against C. albicans.

Configuration of electro-optic fire source detection system

NASA Astrophysics Data System (ADS)

Fabian, Ram Z.; Steiner, Zeev; Hofman, Nir

2007-04-01

The recent fighting activities in various parts of the world have highlighted the need for accurate fire source detection on one hand and fast "sensor to shooter cycle" capabilities on the other. Both needs can be met by the SPOTLITE system which dramatically enhances the capability to rapidly engage hostile fire source with a minimum of casualties to friendly force and to innocent bystanders. Modular system design enable to meet each customer specific requirements and enable excellent future growth and upgrade potential. The design and built of a fire source detection system is governed by sets of requirements issued by the operators. This can be translated into the following design criteria: I) Long range, fast and accurate fire source detection capability. II) Different threat detection and classification capability. III) Threat investigation capability. IV) Fire source data distribution capability (Location, direction, video image, voice). V) Men portability. ) In order to meet these design criteria, an optimized concept was presented and exercised for the SPOTLITE system. Three major modular components were defined: I) Electro Optical Unit -Including FLIR camera, CCD camera, Laser Range Finder and Marker II) Electronic Unit -including system computer and electronic. III) Controller Station Unit - Including the HMI of the system. This article discusses the system's components definition and optimization processes, and also show how SPOTLITE designers successfully managed to introduce excellent solutions for other system parameters.

Evolution of Electron Transport Chains During the Anaerobic to Aerobic Transition on Early Earth

NASA Astrophysics Data System (ADS)

Sepúlveda, R.; Ortiz, R.; Holmes, D. S.

2015-12-01

Sepulveda, R., Ortiz R. and Holmes DS. Center for Bioinformatics and Genome Biology, Fundacion Ciencia y Vida, and Facultad de Ciencias Biologicas, Universidad Andres Bello, Santiago, Chile.According to several models, life emerged on earth in an anoxic environment where oxygen was not available as a terminal electron acceptor for energy generating reactions. After the Great Oxidation Event (GOE) about 2.4 billion years ago, or perhaps even before the GOE, oxygen became the most widespread and efficient terminal electron acceptor and was accompanied by the evolution of a number of redox proteins that could deliver electrons to reduce oxygen to water. Where did these proteins come from? One hypothesis is that they evolved by the neofunctionalization of previously existing redox proteins that had been used in anaerobic conditions as terminal electron donors to reduce compounds such as perchlorate, nitric oxide or iron. We have used a number of bioinformatic tools to explore a large number of genomes looking for discernable signals of such redeployment of function. A Perl pipeline was designed to detect sequence similarity, conserved gene context, remote homology detection, identification of domains and functional evolution of electron carrier proteins from extreme acidophiles, including the small blue copper protein rusticyanin (involved in FeII oxidation), cytochrome oxidase subunit II and quinol-dependent nitric oxide reductase (qNOR). The protein folds and copper binding sites of rusticyanin are conserved in cytochrome oxidase aa3 subunit II, a protein complex that is responsible for the final passage of electrons to reduce oxygen. Therefore, we hypothesize that rusticyanin, cytochrome oxidase II and qNOR are evolutionarily related. Acknowledgments: Fondecyt 1130683.

49 CFR Appendix C to Part 236 - Safety Assurance Criteria and Processes

Code of Federal Regulations, 2011 CFR

2011-10-01

.../Programmable/Electronic Safety (E/E/P/ES) Related Systems, Parts 1-7 as follows: (A) IEC 61508-1 (1998-12) Part.... (B) IEC 61508-2 (2000-05) Part 2: Requirements for electrical/electronic/programmable electronic...

49 CFR Appendix C to Part 236 - Safety Assurance Criteria and Processes

Code of Federal Regulations, 2012 CFR

2012-10-01

.../Programmable/Electronic Safety (E/E/P/ES) Related Systems, Parts 1-7 as follows: (A) IEC 61508-1 (1998-12) Part.... (B) IEC 61508-2 (2000-05) Part 2: Requirements for electrical/electronic/programmable electronic...

49 CFR Appendix C to Part 236 - Safety Assurance Criteria and Processes

Code of Federal Regulations, 2014 CFR

2014-10-01

.../Programmable/Electronic Safety (E/E/P/ES) Related Systems, Parts 1-7 as follows: (A) IEC 61508-1 (1998-12) Part.... (B) IEC 61508-2 (2000-05) Part 2: Requirements for electrical/electronic/programmable electronic...

49 CFR Appendix C to Part 236 - Safety Assurance Criteria and Processes

Code of Federal Regulations, 2013 CFR

2013-10-01

.../Programmable/Electronic Safety (E/E/P/ES) Related Systems, Parts 1-7 as follows: (A) IEC 61508-1 (1998-12) Part.... (B) IEC 61508-2 (2000-05) Part 2: Requirements for electrical/electronic/programmable electronic...

Maxwell's Enduring Legacy

NASA Astrophysics Data System (ADS)

Longair, Malcolm

2016-07-01

Preface; Acknowledgements; Figure credits; Part I. To 1874: 1. Physics in the nineteenth century; 2. Mathematics and physics in Cambridge in the nineteenth century; Part II. 1874 to 1879: 3. The Maxwell era; Part III. 1879 to 1884: 4. Rayleigh's Quinquennium; Part IV. 1884 to 1919: 5. The challenges facing J. J. Thomson; 6. The J. J. Thomson era, 1884-1900 - the electron; 7. The Thomson era, 1900-19 - atomic structure; Part V. 1919 to 1937: 8. Rutherford at McGill and Manchester Universities - new challenges in Cambridge; 9. The Rutherford era - the radioactivists; 10. Rutherford era - the seeds of the new physics; Part VI. 1938 to 1953: 11. Bragg and the war years; 12. Bragg and the post-war years; Part VII. 1953 to 1971: 13. The Mott era - an epoch of expansion; 14. The Mott era - radio astronomy and high energy physics; 15. The Mott era - the growth of condensed matter physics; Part VIII. 1971 to 1982: 16. The Pippard era - a new laboratory and a new vision; 17. The Pippard era - radio astronomy, high energy physics and laboratory astrophysics; 18. The Pippard era - condensed matter physics; Part IX. 1984 to 1995: 19. The Edwards era - a new epoch of expansion; 20. The Edwards era - new directions in condensed matter physics; 21. The Edwards era - high energy physics and radio astronomy; Part X. 1995 to present: 22. Towards the new millennium and beyond; 23. The evolution of the New Museums site; Notes; Bibliography; Author index; Index.

Relation between the Z-1 type expansion of the total energy of isoelectronic atoms and the many-electron theory on the electron correlation by Sinanoǧlu

NASA Astrophysics Data System (ADS)

Anno, Tosinobu; Teruya, Hirohide

1987-07-01

By applying the economical formula for the total energies of isoelectronic atoms presented by the present authors [J. Chem. Phys. 84, 6895 (1986)] to both the nonrelativistic exact energy and the Hartree-Fock energy, an expression of the Z-1 expansion type for the correlation energy is obtained for isoelectronic series involving the first-row atoms. Based upon the expression obtained, the following conclusions are derived on the relation between the Z-1 type expansion theory and Sinanoǧlu's many-electron theory (MET): (i) the Z2 term has nothing to do with the electron correlation; (ii) the term proportional to Z represents the internal correlation energy Eint in MET, at least when Z is large in comparison with the number of electrons N; (iii) the constant term in the Z-1 type expansion is the limiting value of the sum of the semi-internal and the all-external correlation energy (EF+Eu) when Z→∞ and its values for the ground-state atoms show a systematic trend when plotted against N; (iv) the sum of the Z-1 and the higher order terms in Z-1 represents the Z dependence of EF+Eu, although its small amount is attributable to a part of Eint when Z-N≲1.

Observation of Fermi arcs in the type-II Weyl semimetal candidate WTe 2

DOE PAGES

Wu, Yun; Mou, Daixiang; Jo, Na Hyun; ...

2016-09-14

We use ultrahigh resolution, tunable, vacuum ultraviolet laser angle-resolved photoemission spectroscopy (ARPES) to study the electronic properties of WTe 2, a material that was predicted to be a type-II Weyl semimetal. The Weyl fermion states in WTe 2 were proposed to emerge at the crossing points of electron and hole pockets, and Fermi arcs connecting electron and hole pockets would be visible in the spectral function on (001) surface. Here we report the observation of such Fermi arcs in WTe 2 confirming the theoretical predictions. This provides strong evidence for type-II Weyl semimetallic states in WTe 2. Here, we alsomore » find that trivial and topological domains coexist on the same surface of the sample due to the presence of inhomogeneous strain detected by scanning electron microscopy data. This is in agreement with the theoretical prediction that strain can drive this system from topological Weyl to trivial semimetal. WTe 2 therefore provides a tunable playground for studying exotic topological quantum effects.« less

A bioinspired redox relay that mimics radical interactions of the Tyr-His pairs of photosystem II

NASA Astrophysics Data System (ADS)

Megiatto, Jackson D., Jr.; Méndez-Hernández, Dalvin D.; Tejeda-Ferrari, Marely E.; Teillout, Anne-Lucie; Llansola-Portolés, Manuel J.; Kodis, Gerdenis; Poluektov, Oleg G.; Rajh, Tijana; Mujica, Vladimiro; Groy, Thomas L.; Gust, Devens; Moore, Thomas A.; Moore, Ana L.

2014-05-01

In water-oxidizing photosynthetic organisms, light absorption generates a powerfully oxidizing chlorophyll complex (P680•+) in the photosystem II reaction centre. This is reduced via an electron transfer pathway from the manganese-containing water-oxidizing catalyst, which includes an electron transfer relay comprising a tyrosine (Tyr)-histidine (His) pair that features a hydrogen bond between a phenol group and an imidazole group. By rapidly reducing P680•+, the relay is thought to mitigate recombination reactions, thereby ensuring a high quantum yield of water oxidation. Here, we show that an artificial reaction centre that features a benzimidazole-phenol model of the Tyr-His pair mimics both the short-internal hydrogen bond in photosystem II and, using electron paramagnetic resonance spectroscopy, the thermal relaxation that accompanies proton-coupled electron transfer. Although this artificial system is much less complex than the natural one, theory suggests that it captures the essential features that are important in the function of the relay.

Observation of Fermi arcs in the type-II Weyl semimetal candidate WTe 2

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

Wu, Yun; Mou, Daixiang; Jo, Na Hyun

We use ultrahigh resolution, tunable, vacuum ultraviolet laser angle-resolved photoemission spectroscopy (ARPES) to study the electronic properties of WTe 2, a material that was predicted to be a type-II Weyl semimetal. The Weyl fermion states in WTe 2 were proposed to emerge at the crossing points of electron and hole pockets, and Fermi arcs connecting electron and hole pockets would be visible in the spectral function on (001) surface. Here we report the observation of such Fermi arcs in WTe 2 confirming the theoretical predictions. This provides strong evidence for type-II Weyl semimetallic states in WTe 2. Here, we alsomore » find that trivial and topological domains coexist on the same surface of the sample due to the presence of inhomogeneous strain detected by scanning electron microscopy data. This is in agreement with the theoretical prediction that strain can drive this system from topological Weyl to trivial semimetal. WTe 2 therefore provides a tunable playground for studying exotic topological quantum effects.« less

40 CFR Appendix II to Part 1045 - Duty Cycles for Propulsion Marine Engines

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 33 2011-07-01 2011-07-01 false Duty Cycles for Propulsion Marine...) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM SPARK-IGNITION PROPULSION MARINE ENGINES AND VESSELS Pt. 1045, App. II Appendix II to Part 1045—Duty Cycles for Propulsion Marine Engines (a) The...

40 CFR Appendix II to Part 1045 - Duty Cycles for Propulsion Marine Engines

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 33 2014-07-01 2014-07-01 false Duty Cycles for Propulsion Marine...) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM SPARK-IGNITION PROPULSION MARINE ENGINES AND VESSELS Pt. 1045, App. II Appendix II to Part 1045—Duty Cycles for Propulsion Marine Engines (a) The...

40 CFR Appendix II to Part 1045 - Duty Cycles for Propulsion Marine Engines

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 34 2013-07-01 2013-07-01 false Duty Cycles for Propulsion Marine...) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM SPARK-IGNITION PROPULSION MARINE ENGINES AND VESSELS Pt. 1045, App. II Appendix II to Part 1045—Duty Cycles for Propulsion Marine Engines (a) The...

40 CFR Appendix II to Part 1045 - Duty Cycles for Propulsion Marine Engines

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 34 2012-07-01 2012-07-01 false Duty Cycles for Propulsion Marine...) AIR POLLUTION CONTROLS CONTROL OF EMISSIONS FROM SPARK-IGNITION PROPULSION MARINE ENGINES AND VESSELS Pt. 1045, App. II Appendix II to Part 1045—Duty Cycles for Propulsion Marine Engines (a) The...

THE DISCREPANT KINEMATICS OF ORLs AND CELs IN NGC 7009 AS A FUNCTION OF IONIZATION STRUCTURE

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

Richer, Michael G.; Georgiev, Leonid; Torres-Peimbert, Silvia

2013-08-20

We present spatially and velocity-resolved echelle spectroscopy for NGC 7009 obtained with the UVES spectrograph at the European Southern Observatory's Very Large Telescope. Our objective is to analyze the kinematics of emission lines excited by recombination and collisions with electrons to determine whether similarities or differences could be useful in elucidating the well-known abundance discrepancy derived from them. We construct position-velocity maps for recombination, fluorescence, charge transfer, and collisionally excited lines. We find a plasma component emitting in the C II, N II, O II, and Ne II recombination lines whose kinematics are discrepant: they are incompatible with the ionizationmore » structure derived from all other evidence and the kinematics derived from all of these lines are unexpectedly very similar. We find direct evidence for a recombination contribution to [N II] {lambda}5755. Once taken into account, the electron temperatures from [N II], [O III], and [Ne III] agree at a given position and velocity. The electron densities derived from [O II] and [Ar IV] are consistent with direct imaging and the distribution of hydrogen emission. The kinematics of the C II, N II, O II, and Ne II lines does not coincide with the kinematics of the [O III] and [Ne III] forbidden emission, indicating that there is an additional plasma component to the recombination emission that arises from a different volume from that giving rise to the forbidden emission from the parent ions within NGC 7009. Thus, the chemical abundances derived from either type of line are correct only for the plasma component from which they arise. Apart from [N II] {lambda}5755, we find no anomaly with the forbidden lines usually used to determine chemical abundances in ionized nebulae, so the abundances derived from them should be reliable for the medium from which they arise.« less

Rotaxanes and Photovoltaic Materials Based on Pi-Conjugated Donors and Acceptors: Toward Energy Transduction on the Nanoscale

NASA Astrophysics Data System (ADS)

Bruns, Carson J.

The flow of energy between its various forms is central to our understanding of virtually all natural phenomena, from the origins and fate of the universe to the mechanisms that underpin Life. Therefore, a deeper fundamental understanding of how to manage energy processes at the molecular scale will open new doors in science and technology. This dissertation describes organic molecules and materials that are capable of transducing various forms of energy on the nanoscale, namely, a class of mechanically interlocked molecules known as rotaxanes for electrochemical-to-mechanical energy transduction (Part I), and a class of thin films known as organic photovoltaics (OPVs) for solar-to-electric energy transduction (Part II). These materials are all based on conjugated molecules with a capacity to donate or accept pi-electrons. A contemporary challenge in molecular nanotechnology is the development of artificial molecular machines (AMMs) that mimic the ability of motor proteins (e.g. myosin, kinesin) to perform mechanical work by leveraging a combination of energy sources and rich structural chemistry. Part I describes the synthesis, characterization, molecular dynamics, and switching properties of a series of `daisy chain' and oligorotaxane AMM prototypes. All compounds are templated by charge transfer and hydrogen bonding interactions between pi-associated 1,5-dioxynaphthlene donors appended with polyether groups and pi-acceptors of either neutral (naphthalenediimide) or charged (4,4´-bipyridinium) varieties, and are synthesized using efficient one-pot copper(I)-catalyzed azide-alkyne cycloaddition `click chemistry' protocols. The interlocked architectures of these rotaxanes enable them to express sophisticated secondary structures (i.e. foldamers) and mechanical motions in solution, which have been elucidated using dynamic 1H NMR spectroscopy. Furthermore, molecular dynamics simulations, cyclic voltammetry, and spectroelectrochemistry experiments have demonstrated that the muscle-like contractile-extensile motions of the daisy chains can be controlled by redox or thermal stimuli. It is concluded that donor-acceptor daisy chains and oligorotaxanes of unprecendented complexity can be readily prepared using click chemistry and actuated in solution. Motivated by the global demand for low-cost renewable energy, novel pi-donor molecules based on thiophene and diketopyrrolopyrrole (DPP) moieties are investigated in the context of thin-film materials for OPV technologies in Part II. Homologous families of small-molecule donors have been synthesized to investigate the effects of various molecular design principles on the morphological, optical, electronic, and photovoltaic properties of the corresponding thin-film materials. This strategy has been executed in the context of inorganic-organic hybrid OPVs and also more conventional bulk heterojunction (BHJ) OPVs. In the former case, a series of terthiophene surfactants with systematic variations in valency, geometry, and flexibility are electrodeposited on transparent electrodes from aqueous solutions to yield lamellar Zn(OH)2 materials with nanoscale periodicity, which are characterized by scanning electron miscroscopy and two-dimensional grazing incidence X-ray scattering. It is concluded that monovalent, flexible, linear surfactants yield the most dense and anisotropic nanostructures that are ideal for OPVs. For BHJ OPVs, the family of compounds under investigation are small molecule (SM) donors based on electron-rich heterocyclic acenes (benzodithiophene, benzodifuran, naphtho-dithiophene) and electron-poor thiophene-flanked DPP units. Single crystal X-ray structures of the SM donors are compared with morphological, hole mobility, photovoltaic efficiency data on their blends with a common fullerene acceptor to elucidate the optimal molecular design principles for this class of OPVs. It is concluded that the best-performing molecules have a symmetric architecture in which the central acene core comprises an extended pi-system.

Dissecting Diversity Part II

ERIC Educational Resources Information Center

Matthews, Frank

2005-01-01

This article presents "Dissecting Diversity, Part II," the conclusion of a wide-ranging two-part roundtable discussion on diversity in higher education. The participants were as follows: Lezli Baskerville, J.D., President and CEO of the National Association for Equal Opportunity (NAFEO); Dr. Gerald E. Gipp, Executive Director of the…

Ultrastructural particularities of the spermatozoon of the cestode Electrotaenia malopteruri (Fritsch, 1886) (Proteocephalidae: Gangesiinae), a parasite of Malapterurus electricus (Siluriformes: Malapteruridae) from the river Nile, Egypt.

PubMed

Brunanská, Magdaléna; Scholz, Tomás; Ibraheem, Mohammed Hassan

2004-06-01

The fine structure of the mature spermatozoon of the tapeworm Electrotaenia malopteruri (Fritsch, 1886), a member of a supposedly primitive group of proteocephalidean tapeworms (Proteocephalidae: Gangesiinae), was studied by transmission electron microscopy for the first time. The mature spermatozoon of E. malopteruri is filiform, tapers at both extremities, and contains two axonemes of 9+"1" trepaxonematan type. A helicoidal crested body (60-150 nm thick) is present at the anterior extremity of the gamete. The twisting cortical microtubules (CM) line the periphery of the spermatozoon continuously. The nucleus, a fine cord of moderately condensed chromatin, occupies the middle part (region III) of the spermatozoon. The slightly electron-dense cytoplasm contains electron-dense granules in regions II and III and becomes more electron-dense at the end of region IV. The anterior and posterior extremities of the spermatozoon contain a single axoneme. Two modes of disorganisation of the axoneme at the posterior end of the mature spermatozoa are described for the first time in cestodes. The present data also indicate that the sperm ultrastructure of E. malapteruri shows some characters typical for onchobothriid tetraphyllideans, but it resembles that of Cyclophyllidea in the arrangement of twisting of the CM.

Recent Economic Perspectives on Political Economy, Part II*

PubMed Central

Dewan, Torun; Shepsle, Kenneth A.

2013-01-01

In recent years some of the best theoretical work on the political economy of political institutions and processes has begun surfacing outside the political science mainstream in high quality economics journals. This two-part paper surveys these contributions from a recent five-year period. In Part I, the focus is on elections, voting and information aggregation, followed by treatments of parties, candidates, and coalitions. In Part II, papers on economic performance and redistribution, constitutional design, and incentives, institutions, and the quality of political elites are discussed. Part II concludes with a discussion of the methodological bases common to economics and political science, the way economists have used political science research, and some new themes and arbitrage opportunities. PMID:23606754

Assessment of wavelength-dependent parameters of photosynthetic electron transport with a new type of multi-color PAM chlorophyll fluorometer.

PubMed

Schreiber, Ulrich; Klughammer, Christof; Kolbowski, Jörg

2012-09-01

Technical features of a novel multi-color pulse amplitude modulation (PAM) chlorophyll fluorometer as well as the applied methodology and some typical examples of its practical application with suspensions of Chlorella vulgaris and Synechocystis PCC 6803 are presented. The multi-color PAM provides six colors of pulse-modulated measuring light (peak-wavelengths at 400, 440, 480, 540, 590, and 625 nm) and six colors of actinic light (AL), peaking at 440, 480, 540, 590, 625 and 420-640 nm (white). The AL can be used for continuous illumination, maximal intensity single-turnover pulses, high intensity multiple-turnover pulses, and saturation pulses. In addition, far-red light (peaking at 725 nm) is provided for preferential excitation of PS I. Analysis of the fast fluorescence rise kinetics in saturating light allows determination of the wavelength- and sample-specific functional absorption cross section of PS II, Sigma(II)(λ), with which the PS II turnover rate at a given incident photosynthetically active radiation (PAR) can be calculated. Sigma(II)(λ) is defined for a quasi-dark reference state, thus differing from σ(PSII) used in limnology and oceanography. Vastly different light response curves for Chlorella are obtained with light of different colors, when the usual PAR-scale is used. Based on Sigma(II)(λ) the PAR, in units of μmol quanta/(m(2) s), can be converted into PAR(II) (in units of PS II effective quanta/s) and a fluorescence-based electron transport rate ETR(II) = PAR(II) · Y(II)/Y(II)(max) can be defined. ETR(II) in contrast to rel.ETR qualifies for quantifying the absolute rate of electron transport in optically thin suspensions of unicellular algae and cyanobacteria. Plots of ETR(II) versus PAR(II) for Chlorella are almost identical using either 440 or 625 nm light. Photoinhibition data are presented suggesting that a lower value of ETR(II)(max) with 440 nm possibly reflects photodamage via absorption by the Mn-cluster of the oxygen-evolving complex.

Electronic transition moment for the B(2)II-X(2)II system of NO

NASA Technical Reports Server (NTRS)

Luque, Jorge; Crosley, David R.

1995-01-01

The upsilon' = 0-3 and 7 vibrational levels of the NO B(2)II state have been selectively excited by laser radiation. The fluorescence spectra together with calculated Franck-Condon factors and r-centroids have been used to evaluate the electronic transition moment. The results for upsilon' = 0-3 are in very good agreement with recent chemiluminescence measurements and ab initio calculations. Furthermore, the data from upsilon' = 7 have been used to extend the empirically determined moment to limits 1.23 and 1.78 A, improving agreement with experimentally determined lifetimes.

17 CFR 23.202 - Daily trading records.

Code of Federal Regulations, 2014 CFR

2014-04-01

..., instant messaging, chat rooms, electronic mail, mobile device, or other digital or electronic media. Such...; (ii) Moneys borrowed and moneys loaned; (iii) The daily calculation of the value of each outstanding... rooms, electronic mail, mobile device, or other digital or electronic media; (2) Reliable timing data...

17 CFR 23.202 - Daily trading records.

Code of Federal Regulations, 2013 CFR

2013-04-01

..., instant messaging, chat rooms, electronic mail, mobile device, or other digital or electronic media. Such...; (ii) Moneys borrowed and moneys loaned; (iii) The daily calculation of the value of each outstanding... rooms, electronic mail, mobile device, or other digital or electronic media; (2) Reliable timing data...

40 CFR Appendix B to Subpart II of... - Maximum Allowable Thinning Rates as a Function of As Supplied VOC Content and Thinner Density

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 11 2013-07-01 2013-07-01 false Maximum Allowable Thinning Rates as a Function of As Supplied VOC Content and Thinner Density B Appendix B to Subpart II of Part 63 Protection of... Shipbuilding and Ship Repair (Surface Coating) Pt. 63, Subpt. II, App. B Appendix B to Subpart II of Part 63...

40 CFR Appendix B to Subpart II to... - Maximum Allowable Thinning Rates as a Function of As Supplied VOC Content and Thinner Density

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 10 2011-07-01 2011-07-01 false Maximum Allowable Thinning Rates as a Function of As Supplied VOC Content and Thinner Density B Appendix B to Subpart II to Part 63 Protection of... Shipbuilding and Ship Repair (Surface Coating) Pt. 63, Subpt. II, App. B Appendix B to Subpart II to Part 63...

Spectrum simulation in DTSA-II.

PubMed

Ritchie, Nicholas W M

2009-10-01

Spectrum simulation is a useful practical and pedagogical tool. Particularly with complex samples or trace constituents, a simulation can help to understand the limits of the technique and the instrument parameters for the optimal measurement. DTSA-II, software for electron probe microanalysis, provides both easy to use and flexible tools for simulating common and less common sample geometries and materials. Analytical models based on (rhoz) curves provide quick simulations of simple samples. Monte Carlo models based on electron and X-ray transport provide more sophisticated models of arbitrarily complex samples. DTSA-II provides a broad range of simulation tools in a framework with many different interchangeable physical models. In addition, DTSA-II provides tools for visualizing, comparing, manipulating, and quantifying simulated and measured spectra.

Isolation, Characterization and Antitumour Propirties of the 1,2-Popylenediaminetetraacetate trans-Diaqua-Copper (II)

PubMed Central

Kamah, S.; Vilaplana, R.; Moreno, J.; Akdi, K.; García-Herdugo, G.

2000-01-01

A trans-diaquacomplex formed by copper(II) sulphate and the sequestering polyamminopolycarboxylic ligand 1,2-propylenediaminetetraacetic acid (PDTA) has been isolated and characterized by chemical analysis, titrimetry, FT-IR and electronic spectroscopy, Potentiometric and electronic measurements identified the ligand as tetradentate, two nitrogen and two oxygen atoms being bonded to the Cu(II) in planar positions. This octahedral monomeric soluble compound, is an unusual example of a copper (II) substance showing significant in vitro antitumour activity against the human ovarian tumour cells TG (ID50 = 2.29 μM at 48 h) and important in vivo antitumour activity against solid Sarcoma 180 with complete regression of the tumour at a dose of 12.5 mg/Kg body weight. PMID:18475948

Photosensitized H2 Production Using a Zinc Porphyrin-Substituted Protein, Platinum Nanoparticles, and Ascorbate with No Electron Relay: Participation of Good's Buffers.

PubMed

Clark, Emily R; Kurtz, Donald M

2017-04-17

Development of efficient light-driven splitting of water, 2H 2 O → 2H 2 + O 2 , often attempts to optimize photosensitization of the reductive and oxidative half-reactions individually. Numerous homogeneous and heterogeneous systems have been developed for photochemical stimulation of the reductive half reaction, 2H + + 2e - → H 2 . These systems generally consist of various combinations of a H + reduction catalyst, a photosensitizer (PS), and a "sacrificial" electron donor. Zinc(II)-porphyrins (ZnPs) have frequently been used as PSs for H 2 generation, but they are subject to various self-quenching processes in aqueous solutions. Colloidal platinum in nanoparticle form (Pt NP) is a classical H + reduction catalyst using ZnP photosensitizers, but efficient photosensitized H 2 generation requires an electron relay molecule between ZnP and Pt NP. The present report describes an aqueous system for visible (white) light-sensitized generation of H 2 using a protein-embedded Zn(II)-protoporphyrin IX as PS and Pt NP as H + reduction catalyst without an added electron relay. This system operated efficiently in piperazino- and morpholino-alkylsulfonic acid (Good's buffers), which served as sacrificial electron donors. The system also required ascorbate at relatively modest concentrations, which stabilized the Zn(II)-protoporphyrin IX against photodegradation. In the absence of an electron relay molecule, the photosensitized H 2 generation must involve formation of at least a transient complex between a protein-embedded Zn(II)-protoporphyrin IX species and Pt NP.

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

White, Travis A.; Witt, Suzanne E.; Li, Zhanyong

Formamidinate-bridged Rh 2 II,II complexes containing diimine ligands of the formula cis-[Rh 2 II,II(μ-DTolF) 2(NN) 2] 2+ (Rh 2-NN 2), where DTolF = p-ditolylformamidinate and NN = dppn (benzo[i]dipyrido[3,2-a:2',3'-h]quinoxaline), dppz (dipyrido[3,2-a:2',3'-c]phenazine), and phen (1,10-phenanthroline), electrocatalytically reduce H + to H 2 in DMF solutions containing CH 3COOH at a glassy carbon electrode. Cathodic scans in the absence of acid display a Rh III,II/II,II reduction at -0.90 V vs Fc +/Fc followed by NN 0/– reduction at -1.13, -1.36, and -1.65 V for Rh 2-dppn 2, Rh 2-dppz 2, and Rh 2-phen 2, respectively. Upon the addition of acid, Rh 2-dppnmore » 2 and Rh 2-dppz 2 undergo reduction–protonation–reduction at each pyrazine-containing NN ligand prior to the Rh 2 II,II/II,I reduction. The Rh 2 II,I species is thus protonated at one of the metal centers, resulting in the formation of the corresponding Rh 2 II,III-hydride. In the case of Rh 2-phen 2, the reduction of the phen ligand is followed by intramolecular electron transfer to the Rh 2 II,II core in the presence of protons to form a Rh 2 II,III-hydride species. Further reduction and protonation at the Rh 2 core for all three complexes rapidly catalyzes H 2 formation with varied calculated turnover frequencies (TOF) and overpotential values (η): 2.6 × 10 4 s –1 and 0.56 V for Rh 2-dppn, 2.8 × 10 4 s –1 and 0.50 V for Rh 2-dppz 2, and 5.9 × 10 4 s –1 and 0.64 V for Rh 2-phen 2. Bulk electrolysis confirmed H 2 formation, and further CH 3COOH addition regenerates H 2 production, attesting to the robust nature of the architecture. The cis-[Rh 2 II,II(μ-DTolF) 2(NN) 2] 2+ architecture benefits by combining electron-rich formamidinate bridges, a redox-active Rh 2 II,II core, and electron-accepting NN diimine ligands to allow for the electrocatalysis of H + substrate to H 2 fuel.« less

Chimeric Lyssavirus Glycoproteins with Increased Immunological Potential

PubMed Central

Jallet, Corinne; Jacob, Yves; Bahloul, Chokri; Drings, Astrid; Desmezieres, Emmanuel; Tordo, Noël; Perrin, Pierre

1999-01-01

The rabies virus glycoprotein molecule (G) can be divided into two parts separated by a flexible hinge: the NH2 half (site II part) containing antigenic site II up to the linear region (amino acids [aa] 253 to 275 encompassing epitope VI [aa 264]) and the COOH half (site III part) containing antigenic site III and the transmembrane and cytoplasmic domains. The structural and immunological roles of each part were investigated by cell transfection and mouse DNA-based immunization with homogeneous and chimeric G genes formed by fusion of the site II part of one genotype (GT) with the site III part of the same or another GT. Various site II-site III combinations between G genes of PV (Pasteur virus strain) rabies (GT1), Mokola (GT3), and EBL1 (European bat lyssavirus 1 [GT5]) viruses were tested. Plasmids pGPV-PV, pGMok-Mok, pGMok-PV, and pGEBL1-PV induced transient expression of correctly transported and folded antigens in neuroblastoma cells and virus-neutralizing antibodies against parental viruses in mice, whereas, pG-PVIII (site III part only) and pGPV-Mok did not. The site III part of PV (GT1) was a strong inducer of T helper cells and was very effective at presenting the site II part of various GTs. Both parts are required for correct folding and transport of chimeric G proteins which have a strong potential value for immunological studies and development of multivalent vaccines. Chimeric plasmid pGEBL1-PV broadens the spectrum of protection against European lyssavirus genotypes (GT1, GT5, and GT6). PMID:9847325

Electron Spin Resonance Studies of Carbonic Anhydrase: Transition Metal Ions and Spin-Labeled Sulfonamides*

PubMed Central

Taylor, June S.; Mushak, Paul; Coleman, Joseph E.

1970-01-01

Electron spin resonance (esr) spectra of Cu(II) and Co(II) carbonic anhydrase, and a spin-labeled sulfonamide complex of the Zn(II) enzyme, are reported. The coordination geometry of Cu(II) bound in the enzyme appears to have approximately axial symmetry. Esr spectra of enzyme complexes with metal-binding anions also show axial symmetry and greater covalency, in the order ethoxzolamide < SH- < N3- ≤ CN-. Well-resolved superhyperfine structure in the spectrum of the cyanide complex suggests the presence of two, and probably three, equivalent nitrogen ligands from the protein. Esr spectra of the Co(II) enzyme and its complexes show two types of Co(II) environment, one typical of the native enzyme and the 1:1 CN- complex, and one typical of a 2:1 CN- complex. Co(II) in the 2:1 complex appears to be low-spin and probably has a coordination number of 5. Binding of a spin-labeled sulfonamide to the active center immobilizes the free radical. The similarity of the esr spectra of spin-labeled Zn(II) and Co(II) carbonic anhydrases suggests that the conformation at the active center is similar in the two metal derivatives. PMID:4320976

12 CFR 7.5001 - Electronic activities that are part of, or incidental to, the business of banking.

Code of Federal Regulations, 2014 CFR

2014-01-01

... 12 Banks and Banking 1 2014-01-01 2014-01-01 false Electronic activities that are part of, or..., DEPARTMENT OF THE TREASURY BANK ACTIVITIES AND OPERATIONS Electronic Activities § 7.5001 Electronic... the criteria that the OCC uses to determine whether an electronic activity is authorized as part of...

12 CFR 7.5001 - Electronic activities that are part of, or incidental to, the business of banking.

Code of Federal Regulations, 2012 CFR

2012-01-01

... 12 Banks and Banking 1 2012-01-01 2012-01-01 false Electronic activities that are part of, or..., DEPARTMENT OF THE TREASURY BANK ACTIVITIES AND OPERATIONS Electronic Activities § 7.5001 Electronic... the criteria that the OCC uses to determine whether an electronic activity is authorized as part of...

12 CFR 7.5001 - Electronic activities that are part of, or incidental to, the business of banking.

Code of Federal Regulations, 2013 CFR

2013-01-01

... 12 Banks and Banking 1 2013-01-01 2013-01-01 false Electronic activities that are part of, or..., DEPARTMENT OF THE TREASURY BANK ACTIVITIES AND OPERATIONS Electronic Activities § 7.5001 Electronic... the criteria that the OCC uses to determine whether an electronic activity is authorized as part of...

12 CFR 7.5001 - Electronic activities that are part of, or incidental to, the business of banking.

Code of Federal Regulations, 2011 CFR

2011-01-01

... 12 Banks and Banking 1 2011-01-01 2011-01-01 false Electronic activities that are part of, or..., DEPARTMENT OF THE TREASURY BANK ACTIVITIES AND OPERATIONS Electronic Activities § 7.5001 Electronic... the criteria that the OCC uses to determine whether an electronic activity is authorized as part of...

Phenol oxidation through its adduct formation with chromium complex of 1,4,8,11-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane: A theoretical study

NASA Astrophysics Data System (ADS)

Narayanan, Jayanthi; Guadalupe, Hernández J.; Thangarasu, Pandiyan

2017-04-01

Structural and electronic properties of [cis-[Cr(tmpcH)X2]n+ (n = 2 or 4; X = OH-, Cl-, Br- and H2O; tmpcH = 1,4,8,11-tetrakis(2-pyridylmethyl)-1,4,8,11-tetraazacyclotetradecane were analyzed by DFT and TD-DFT methods. The local reactivity active site of the ligand was determined by the condensed-to atom Fukui indexes (CAFI) f(r). In the study, the axial bond distance with metal ion undergoes a considerable change from shorter to longer as OH < Cl- < Br- < H2O, agreeing with the molecular orbital analysis where the dz2 energy is lowered for OH- compared to H2O at the axial position. After analyzing the geometrical data collected from literature for the complexes of Cr(II), Mn(II), Fe(II), Co(II), Ni(II), Cu(II), and Zn (II) with tmpcH, it was found that the bond distance decreases with increasing number of d-electrons in the 3d orbital, suggesting that the over-lapping of oribital (π) from Npy with the metal d-orbital is more effective than those from Ncyclam with metal d-orbital. Therefore, the change of different oxidation states for [cis-[Cr(tmpcH)X2]n+ influences significantly the geometrical and electronic parameters. For cis-[Cr(tmpcH)Cl2]2+ the calculated bands are red shifted except for the lower energy band (595 nm) which agrees qualitatively with the experimental one; in addition, the effect of solvent on the electronic transition was analyzed. Furthermore, we collected the electronic data for several chromium complexes from the literature, and compared with our results by plotting the data against number of chromium compounds. Finally, the phenol oxidation properties of the chromium complexes were studied, and phenol forms an adduct with [Cr(tmpcH)Cl]3+ to yield [Cr(tmpcH)Cl-OPh]2+ which could produce the phenol radical, which is enhanced by the presence of -OCH3 group at para- position in the phenolic ring.

19 CFR 210.8 - Commencement of preinstitution proceedings.

Code of Federal Regulations, 2012 CFR

2012-04-01

... electronic form on CD-ROM, DVD, or other portable electronic media approved by the Secretary. (ii) An... CD-ROM, DVD, or other portable electronic media approved by the Secretary. (iii) For each proposed... version of the motion shall be filed in electronic form on CD-ROM, DVD, or other portable electronic media...

19 CFR 210.8 - Commencement of preinstitution proceedings.

Code of Federal Regulations, 2013 CFR

2013-04-01

... electronic form on CD-ROM, DVD, or other portable electronic media approved by the Secretary. (ii) An... CD-ROM, DVD, or other portable electronic media approved by the Secretary. (iii) For each proposed... version of the motion shall be filed in electronic form on CD-ROM, DVD, or other portable electronic media...

19 CFR 210.8 - Commencement of preinstitution proceedings.

Code of Federal Regulations, 2014 CFR

2014-04-01

... electronic form on CD-ROM, DVD, or other portable electronic media approved by the Secretary. (ii) An... CD-ROM, DVD, or other portable electronic media approved by the Secretary. (iii) For each proposed... version of the motion shall be filed in electronic form on CD-ROM, DVD, or other portable electronic media...

21 CFR 1305.25 - Unaccepted and defective electronic orders.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 9 2010-04-01 2010-04-01 false Unaccepted and defective electronic orders. 1305... SCHEDULE I AND II CONTROLLED SUBSTANCES Electronic Orders § 1305.25 Unaccepted and defective electronic orders. (a) No electronic order may be filled if: (1) The required data fields have not been completed...

21 CFR 1305.25 - Unaccepted and defective electronic orders.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 9 2014-04-01 2014-04-01 false Unaccepted and defective electronic orders. 1305... SCHEDULE I AND II CONTROLLED SUBSTANCES Electronic Orders § 1305.25 Unaccepted and defective electronic orders. (a) No electronic order may be filled if: (1) The required data fields have not been completed...

Probing the electronic structure of platinum(II) chromophores: crystal structures, NMR structures, and photophysical properties of six new bis- and di- phenolate/thiolate Pt(II)diimine chromophores.

PubMed

Weinstein, Julia A; Tierney, Mark T; Davies, E Stephen; Base, Karel; Robeiro, Anthony A; Grinstaff, Mark W

2006-05-29

A general route for synthesis of six structurally similar Pt(II) diimine thiolate/phenolates chromophores possessing bulky phenolate or thiolate ligands is reported. The Pt chromophores were characterized using an array of techniques including 1H, 13C, and 195Pt NMR, absorption, emission, (spectro)electrochemistry, and EPR spectroscopy. Systematic variation of the electronic structure of the Pt(II) chromophores studied was achieved by (i) changing solvent polarity; (ii) substituting oxygen for sulfur in the donor ligand; (iii) alternating donor ligands from bis- to di-coordination; and (iv) changing the electron donating/withdrawing properties of the ligand(s). The lowest excited state in these new chromophores was assigned to a [charge-transfer-to-diimine] transition from the HOMO of mixed Pt/S (or Pt/O) character on the basis of absorption and emission spectroscopy, UV/vis (spectro)electrochemistry, and EPR spectroscopy. One of the chromophores, Pt(dpphen)(3,5-di-tert-butyl-catecholate) represents an example of a Pt(II) diimine phenolate chromophore that possesses a reversible oxidation centered predominantly on the donor ligand. Results from EPR spectroscopy indicate participation of the Pt(II) orbitals in the HOMO. There is a dramatic difference in the photophysical properties of carborane complexes compared to other mixed-ligand Pt(II) compounds, which includes room-temperature emission and photostability. The charge-transfer character of the lowest excited state in this series of chromophores is maintained throughout. Moreover, the absorption and emission energies and the redox properties of the excited state can be significantly tuned.

Binding of manganese(II) to a tertiary stabilized hammerhead ribozyme as studied by electron paramagnetic resonance spectroscopy

PubMed Central

KISSELEVA, NATALIA; KHVOROVA, ANASTASIA; WESTHOF, ERIC; SCHIEMANN, OLAV

2005-01-01

Electron paramagnetic resonance (EPR) spectroscopy is used to study the binding of MnII ions to a tertiary stabilized hammer-head ribozyme (tsHHRz) and to compare it with the binding to the minimal hammerhead ribozyme (mHHRz). Continuous wave EPR measurements show that the tsHHRz possesses a single high-affinity MnII binding site with a KD of ≤10 nM at an NaCl concentration of 0.1 M. This dissociation constant is at least two orders of magnitude smaller than the KD determined previously for the single high-affinity MnII site in the mHHRz. In addition, whereas the high-affinity MnII is displaced from the mHHRz upon binding of the aminoglycoside antibiotic neomycin B, it is not from the tsHHRz. Despite these pronounced differences in binding, a comparison between the electron spin echo envelope modulation and hyperfine sublevel correlation spectra of the minimal and tertiary stabilized HHRz demonstrates that the structure of both binding sites is very similar. This suggests that the MnII is located in both ribozymes between the bases A9 and G10.1 of the sheared G · A tandem base pair, as shown previously and in detail for the mHHRz. Thus, the much stronger MnII binding in the tsHHRz is attributed to the interaction between the two external loops, which locks in the RNA fold, trapping the MnII in the tightly bound conformation, whereas the absence of long-range loop–loop interactions in the mHHRz leads to more dynamical and open conformations, decreasing MnII binding. PMID:15611296

Use of Immunization Information Systems in Primary Care.

PubMed

Kempe, Allison; Hurley, Laura P; Cardemil, Cristina V; Allison, Mandy A; Crane, Lori A; Brtnikova, Michaela; Beaty, Brenda L; Pabst, Laura J; Lindley, Megan C

2017-02-01

Immunization information systems (IISs) are highly effective for increasing vaccination rates but information about how primary care physicians use them is limited. Pediatricians, family physicians (FPs), and general internists (GIMs) were surveyed by e-mail and mail from January 2015 to April 2015 from all states with an existing IIS. Providers were recruited to be representative of national provider organization memberships. Multivariable log binomial regression examined factors associated with IIS use (October 2015-April 2016). Response rates among pediatricians, FPs, and GIMs, respectively, were 75% (325/435), 68% (310/459), and 63% (272/431). A proportion of pediatricians (5%), FPs (14%), and GIMs (48%) did not know there was a state/local IIS; 81%, 72%, and 27% reported using an IIS (p<0.0001). Among those who used IISs, 64% of pediatricians, 61% of FPs, and 22% of GIMs thought the IIS could tell them a patient's immunization needs; 22%, 29%, and 51% did not know. The most frequently reported major barriers to use included the IIS not updating the electronic medical record (29%, 28%, 35%) and lack of ability to submit data electronically (22%, 27%, 31%). Factors associated with lower IIS use included FP (adjusted risk ratio=0.85; 95% CI=0.75, 0.97) or GIM (adjusted risk ratio=0.33; 95% CI=0.25, 0.42) versus pediatric specialty and older versus younger provider age (adjusted risk ratio=0.96; 95 CI%=0.94, 0.98). There are substantial gaps in knowledge of IIS capabilities, especially among GIMs; barriers to interoperability between IISs and electronic medical records affect all specialties. Closing these gaps may increase use of proven IIS functions including decision support and reminder/recall. Copyright © 2016. Published by Elsevier Inc.

N-benzoylated 1,4,8,11-tetraazacyclotetradecane and their copper(II) and nickel(II) complexes: Spectral, magnetic, electrochemical, crystal structure, catalytic and antimicrobial studies

NASA Astrophysics Data System (ADS)

Nirmala, G.; Rahiman, A. Kalilur; Sreedaran, S.; Jegadeesh, R.; Raaman, N.; Narayanan, V.

2010-09-01

A series of N-benzoylated cyclam ligands incorporating three different benzoyl groups 1,4,8,11-tetra-(benzoyl)-1,4,8,11-tetraazacyclotetradecane (L 1), 1,4,8,11-tetra-(2-nitrobenzoyl)-1,4,8,11-tetraazacyclotetradecane (L 2) and 1,4,8,11-tetra-(4-nitrobenzoyl)-1,4,8,11-tetraazacyclotetradecane (L 3) and their nickel(II) and copper(II) complexes are described. Crystal structure of L 1 is also reported. The ligands and complexes were characterized by elemental analysis, electronic, IR, 1H NMR and 13C NMR spectral studies. N-benzoylation causes red shift in the λmax values of the complexes. The cyclic voltammogram of the complexes of ligand L 1 show one-electron, quasi-reversible reduction wave in the region -1.00 to -1.04 V, whereas that of L 2 and L 3 show two quasi-reversible reduction peaks. Nickel complexes show one-electron quasi-reversible oxidation wave at a positive potential in the range +1.05 to +1.15 V. The ESR spectra of the mononuclear copper(II) complexes show four lines, characteristic of square-planar geometry with nuclear hyperfine spin 3/2. All copper(II) complexes show a normal room temperature magnetic moment values μeff 1.70-1.73 BM which is close to the spin-only value of 1.73 BM. Kinetic studies on the oxidation of pyrocatechol to o-quinone using the copper(II) complexes as catalysts and hydrolysis of 4-nitrophenylphosphate using the copper(II) and nickel(II) complexes as catalysts were carried out. All the ligands and their complexes were also screened for antimicrobial activity against Gram-positive, Gram-negative bacteria and human pathogenic fungi.

Unlearning Established Organizational Routines--Part II

ERIC Educational Resources Information Center

Fiol, C. Marlena; O'Connor, Edward J.

2017-01-01

Purpose: The purpose of Part II of this two-part paper is to uncover important differences in the nature of the three unlearning subprocesses, which call for different leadership interventions to motivate people to move through them. Design/methodology/approach: The paper draws on research in behavioral medicine and psychology to demonstrate that…

Effect of fast electrons on the stability of resistive interchange modes in the TJ-II stellarator

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

García, L.; Ochando, M. A.; Hidalgo, C.

2016-06-15

In this paper, we report on electromagnetic phenomena in low-β plasmas at the TJ-II stellarator, controlled by external heating. To understand the observations qualitatively, we introduce a simple modification of the standard resistive MHD equations, to include the potential impact of fast electrons on instabilities. The dominant instabilities of the modeling regime are resistive interchange modes, and calculations are performed in a configuration with similar characteristics as the TJ-II stellarator. The main effect of the trapping of fast electrons by magnetic islands induced by MHD instabilities is to increase the magnetic component of the fluctuations, changing the character of themore » instability to tearing-like and modifying the frequency of the modes. These effects seem to be consistent with some of the experimental observations.« less

Improvement of the thermo-mechanical position stability of the beam position monitor in the PLS-II

NASA Astrophysics Data System (ADS)

Ha, Taekyun; Hong, Mansu; Kwon, Hyuckchae; Han, Hongsik; Park, Chongdo

2016-09-01

In the storage ring of the Pohang Light Source-II (PLS-II), we reduced the mechanical displacement of the electron-beam position monitors (e-BPMs) that is caused by heating during e-beam storage. The BPM pickup itself must be kept stable to sub-micrometer precision in order for a stable photon beam to be provided to beamlines because the orbit feedback system is programmed to make the electron beam pass through the center of the BPM. Thermal deformation of the vacuum chambers on which the BPM pickups are mounted is inevitable when the electron beam current is changed by an unintended beam abort. We reduced this deformation by improving the vacuum chamber support and by enhancing the water cooling. We report a thermo-mechanical analysis and displacement measurements for the BPM pickups after improvements.

Readout Electronics for the Central Drift Chamber of the Belle-II Detector

NASA Astrophysics Data System (ADS)

Uchida, Tomohisa; Taniguchi, Takashi; Ikeno, Masahiro; Iwasaki, Yoshihito; Saito, Masatoshi; Shimazaki, Shoichi; Tanaka, Manobu M.; Taniguchi, Nanae; Uno, Shoji

2015-08-01

We have developed readout electronics for the central drift chamber (CDC) of the Belle-II detector. The space near the endplate of the CDC for installation of the electronics was limited by the detector structure. Due to the large amounts of data generated by the CDC, a high-speed data link, with a greater than one gigabit transfer rate, was required to transfer the data to a back-end computer. A new readout module was required to satisfy these requirements. This module processes 48 signals from the CDC, converts them to digital data and transfers it directly to the computer. All functions that transfer digital data via the high speed link were implemented on the single module. We have measured its electrical characteristics and confirmed that the results satisfy the requirements of the Belle-II experiment.

Systems approach to excitation-energy and electron transfer reaction networks in photosystem II complex: model studies for chlorophyll a fluorescence induction kinetics.

PubMed

Matsuoka, Takeshi; Tanaka, Shigenori; Ebina, Kuniyoshi

2015-09-07

Photosystem II (PS II) is a protein complex which evolves oxygen and drives charge separation for photosynthesis employing electron and excitation-energy transfer processes over a wide timescale range from picoseconds to milliseconds. While the fluorescence emitted by the antenna pigments of this complex is known as an important indicator of the activity of photosynthesis, its interpretation was difficult because of the complexity of PS II. In this study, an extensive kinetic model which describes the complex and multi-timescale characteristics of PS II is analyzed through the use of the hierarchical coarse-graining method proposed in the authors׳ earlier work. In this coarse-grained analysis, the reaction center (RC) is described by two states, open and closed RCs, both of which consist of oxidized and neutral special pairs being in quasi-equilibrium states. Besides, the PS II model at millisecond scale with three-state RC, which was studied previously, could be derived by suitably adjusting the kinetic parameters of electron transfer between tyrosine and RC. Our novel coarse-grained model of PS II can appropriately explain the light-intensity dependent change of the characteristic patterns of fluorescence induction kinetics from O-J-I-P, which shows two inflection points, J and I, between initial point O and peak point P, to O-J-D-I-P, which shows a dip D between J and I inflection points. Copyright © 2015 Elsevier Ltd. All rights reserved.

On the use of unshielded cables in ionization chamber dosimetry for total-skin electron therapy.

PubMed

Chen, Z; Agostinelli, A; Nath, R

1998-03-01

The dosimetry of total-skin electron therapy (TSET) usually requires ionization chamber measurements in a large electron beam (up to 120 cm x 200 cm). Exposing the chamber's electric cable, its connector and part of the extension cable to the large electron beam will introduce unwanted electronic signals that may lead to inaccurate dosimetry results. While the best strategy to minimize the cable-induced electronic signal is to shield the cables and its connector from the primary electrons, as has been recommended by the AAPM Task Group Report 23 on TSET, cables without additional shielding are often used in TSET dosimetry measurements for logistic reasons, for example when an automatic scanning dosimetry is used. This paper systematically investigates the consequences and the acceptability of using an unshielded cable in ionization chamber dosimetry in a large TSET electron beam. In this paper, we separate cable-induced signals into two types. The type-I signal includes all charges induced which do not change sign upon switching the chamber polarity, and type II includes all those that do. The type-I signal is easily cancelled by the polarity averaging method. The type-II cable-induced signal is independent of the depth of the chamber in a phantom and its magnitude relative to the true signal determines the acceptability of a cable for use under unshielded conditions. Three different cables were evaluated in two different TSET beams in this investigation. For dosimetry near the depth of maximum buildup, the cable-induced dosimetry error was found to be less than 0.2% when the two-polarity averaging technique was applied. At greater depths, the relative dosimetry error was found to increase at a rate approximately equal to the inverse of the electron depth dose. Since the application of the two-polarity averaging technique requires a constant-irradiation condition, it was demonstrated than an additional error of up to 4% could be introduced if the unshielded cable's spatial configuration were altered during the two-polarity measurements. This suggests that automatic scanning systems with unshielded cables should not be used in TSET ionization chamber dosimetry. However, the data did show that an unshielded cable may be used in TSET ionization chamber dosimetry if the size of cable-induced error in a given TSET beam is pre-evaluated and the measurement is carefully conducted. When such an evaluation has not been performed, additional shielding should be applied to the cable being used, making measurements at multiple points difficult.

Extracellular Electron Transfer and Survival Strategies in Acid Mine Drainage Impacted Soils

NASA Astrophysics Data System (ADS)

Gorby, Y. A.; Senko, J.

2011-12-01

Acid mine drainage (AMD) is a prominent and increasing problem in the greater Appalachian region of the United States and throughout the world. Recognition of the importance of extracellular electron transfer (EET) in microbial communities has provided a fertile research environment for multidisciplinary collaborations to emerge and effectively address complex questions with important environmental implications. Our research focuses on the components, strategies and mechanisms of EET in soil systems impacted by AMD and extends to other biogeochemical systems typified by steep redox gradients. Organisms within acid mine drainage use Fe(II) as their primary electron donor and couple Fe(II) oxidation to the reduction of oxygen as the terminal electron acceptor. Biogenic minerals formed by this process completely encase microbes in think deposits that would seem to limit diffusion of both Fe(II) and O2 for access by the organisms. We have developed methods for catalytically removing biogenic minerals revealing microorganisms and a fine network of filamentous extracellular material. Here we present a status report of our efforts to characterize the molecular and electronic properties of these filaments and to address the hypothesis that at least some of these filaments are electrically conductive microbial nanowires that facilitate electron transfer reactions within this complex biogeochemical system.

National Skills Standards Development Program: Organization and Operation of Technical Committees To Develop National Skill Standards for Competency in the Electronics Industry. The Third Party Summative Evaluation of the Electronic Industries Foundation Project. Phase I & II. Final Report.

ERIC Educational Resources Information Center

Losh, Charles

The Electronics Industries Foundation was awarded a project to develop national entry-level standards and a certification system. Ten specialties were included: automotive electronics, avionics, biomedical electronics, business machines, consumer products electronics, general electronics, industrial electronics, instrumentation, microcomputer, and…

Industrial Education. Electricity/Electronics Curriculum Guide, Phase II. Instructional Modules, Level III.

ERIC Educational Resources Information Center

Lillo, Robert E.; Soffiotto, Nicholas S.

Designed for students in the tenth grade, this electricity/electronics curriculum guide contains instructional modules for sixteen units of instruction: (1) orientation, (2) introduction to electricity/electronics, (3) electricity/electronics safety, (4) fundamental skills, (5) direct current circuits, (6) graphical illustrations, (7) circuit…

Guidelines for conducting bulletproof workplace investigations: Part II--searches, surveillance, and other legal issues.

PubMed

Koen, Clifford M; Mitchell, Michael S

2012-01-01

A proper and thorough investigation can help avoid or successfully defend lawsuits. When conducting workplace investigations, employers must take care to conduct reasonable searches and not violate employees' rights to privacy. This article addresses privacy and other legal issues surrounding the use of various types of electronic surveillance including wiretapping, video/photography, and monitoring of e-mail. While conducting such searches, employers must be vigilant in their efforts to avoid liability for defamation and to properly document the investigation. Guidance is provided on these issues along with advice on the recommendation and/or remedial action that may result from the investigation and a checklist of additional considerations when conducting investigations resulting from harassment.

Current-limiting and ultrafast system for the characterization of resistive random access memories.

PubMed

Diaz-Fortuny, J; Maestro, M; Martin-Martinez, J; Crespo-Yepes, A; Rodriguez, R; Nafria, M; Aymerich, X

2016-06-01

A new system for the ultrafast characterization of resistive switching phenomenon is developed to acquire the current during the Set and Reset process in a microsecond time scale. A new electronic circuit has been developed as a part of the main setup system, which is capable of (i) applying a hardware current limit ranging from nanoampers up to miliampers and (ii) converting the Set and Reset exponential gate current range into an equivalent linear voltage. The complete system setup allows measuring with a microsecond resolution. Some examples demonstrate that, with the developed setup, an in-depth analysis of resistive switching phenomenon and random telegraph noise can be made.

Special Features of the Structure of Laser-Welded Joints of Dissimilar Alloys Based on Titanium and Aluminum

NASA Astrophysics Data System (ADS)

Nikulina, A. A.; Smirnov, A. I.; Turichin, G. A.; Klimova-Korsmik, O. G.; Babkin, K. D.

2017-11-01

The structure of laser-welded joints of parts having different thicknesses fabricated from alloys based on aluminum and titanium has been studied. Results of transmission and scanning electron microscopy measurements and x-ray diffraction analysis show that the diffusion interaction of microvolumes of two alloys in the weld leads to the formation of two interlayers: (i) a continuous intermetallic TiAl layer with thickness below 1 μm adjacent to the titanium alloy and (ii) a layer consisting of TiAl3 intermetallic dendrites with thickness of 2 - 6 μm adjacent to the TiAl layer. The average microhardness of the intermetallic layer is about 490 HV.

14 CFR Appendix A to Part 91 - Category II Operations: Manual, Instruments, Equipment, and Maintenance

Code of Federal Regulations, 2010 CFR

2010-01-01

... authorization for the type aircraft checked. (3) A schedule that provides for the performance of bench checks..., Equipment, and Maintenance A Appendix A to Part 91 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Maintenance 1. Category II Manual (a) Application for approval. An applicant for approval of a Category II...

14 CFR Appendix A to Part 91 - Category II Operations: Manual, Instruments, Equipment, and Maintenance

Code of Federal Regulations, 2013 CFR

2013-01-01

... authorization for the type aircraft checked. (3) A schedule that provides for the performance of bench checks..., Equipment, and Maintenance A Appendix A to Part 91 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Maintenance 1. Category II Manual (a) Application for approval. An applicant for approval of a Category II...

14 CFR Appendix A to Part 91 - Category II Operations: Manual, Instruments, Equipment, and Maintenance

Code of Federal Regulations, 2012 CFR

2012-01-01

... authorization for the type aircraft checked. (3) A schedule that provides for the performance of bench checks..., Equipment, and Maintenance A Appendix A to Part 91 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Maintenance 1. Category II Manual (a) Application for approval. An applicant for approval of a Category II...

14 CFR Appendix A to Part 91 - Category II Operations: Manual, Instruments, Equipment, and Maintenance

Code of Federal Regulations, 2014 CFR

2014-01-01

... authorization for the type aircraft checked. (3) A schedule that provides for the performance of bench checks..., Equipment, and Maintenance A Appendix A to Part 91 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Maintenance 1. Category II Manual (a) Application for approval. An applicant for approval of a Category II...

14 CFR Appendix A to Part 91 - Category II Operations: Manual, Instruments, Equipment, and Maintenance

Code of Federal Regulations, 2011 CFR

2011-01-01

... authorization for the type aircraft checked. (3) A schedule that provides for the performance of bench checks..., Equipment, and Maintenance A Appendix A to Part 91 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION... Maintenance 1. Category II Manual (a) Application for approval. An applicant for approval of a Category II...

40 CFR Appendix B to Subpart A of... - Class II Controlled Substances a

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 18 2014-07-01 2014-07-01 false Class II Controlled Substances a B Appendix B to Subpart A of Part 82 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED..., Subpt. A, App. B Appendix B to Subpart A of Part 82—Class II Controlled Substances a Controlled...

40 CFR Appendix II to Part 1045 - Duty Cycles for Propulsion Marine Engines

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Duty Cycles for Propulsion Marine... Pt. 1045, App. II Appendix II to Part 1045—Duty Cycles for Propulsion Marine Engines (a) The following duty cycle applies for discrete-mode testing: E4 Mode No. Enginespeed 1 Torque(percent) 2...

40 CFR Appendix II to Part 1039 - Steady-State Duty Cycles

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 32 2010-07-01 2010-07-01 false Steady-State Duty Cycles II Appendix... Appendix II to Part 1039—Steady-State Duty Cycles (a) The following duty cycles apply for constant-speed engines: (1) The following duty cycle applies for discrete-mode testing: D2 mode number Engine speed...

EUV lines observed with EIS/Hinode in a solar prominence

NASA Astrophysics Data System (ADS)

Labrosse, N.; Schmieder, B.; Heinzel, P.; Watanabe, T.

2011-07-01

Context. During a multi-wavelength observation campaign with Hinode and ground-based instruments, a solar prominence was observed for three consecutive days as it crossed the western limb of the Sun in April 2007. Aims: We report on observations obtained on 26 April 2007 using EIS (Extreme ultraviolet Imaging Spectrometer) on Hinode. They are analysed to provide a qualitative diagnostic of the plasma in different parts of the prominence. Methods: After correcting for instrumental effects, the rasters at different wavelengths are presented. Several regions within the same prominence are identified for further analysis. Selected profiles for lines with formation temperatures between log (T) = 4.7 and log (T) = 6.3, as well as their integrated intensities, are given. The profiles of coronal, transition region, and He ii lines are discussed. We pay special attention to the He ii line, which is blended with coronal lines. Results: Some quantitative results are obtained by analysing the line profiles. They confirm that depression in EUV lines can be interpreted in terms of two mechanisms: absorption of coronal radiation by the hydrogen and neutral helium resonance continua, and emissivity blocking. We present estimates of the He ii line integrated intensity in different parts of the prominence according to different scenarios for the relative contribution of absorption and emissivity blocking to the coronal lines blended with the He ii line. We estimate the contribution of the He ii 256.32 Å line to the He ii raster image to vary between ~44% and 70% of the raster's total intensity in the prominence according to the different models used to take into account the blending coronal lines. The inferred integrated intensities of the He ii 256 Å line are consistent with the theoretical intensities obtained with previous 1D non-LTE radiative transfer calculations, yielding a preliminary estimate of the central temperature of 8700 K, a central pressure of 0.33 dyn cm-2, and a column mass of 2.5 × 10-4 g cm-2. The corresponding theoretical hydrogen column density (1020 cm-2) is about two orders of magnitude higher than those inferred from the opacity estimates at 195 Å. The non-LTE calculations indicate that the He ii 256.32 Å line is essentially formed in the prominence-to-corona transition region by resonant scattering of the incident radiation. The movie associated to Fig. 2 is available in electronic form at http://www.aanda.org

Coordinator(a) de Servicios Clinicos. Parte I (Unidad I-IV). Parte II (Unidad V-VI). Guia. Documento de Trabajo (Clinical Services Coordinator. Part I. Units I-IV. Part II. Units V-VI. Guide. Working Document).

ERIC Educational Resources Information Center

Puerto Rico State Dept. of Education, Hato Rey. Area for Vocational and Technical Education.

This guide is intended for instructing secondary students in the occupation of clinical services coordinator in a hospital. The first part contains four units on the following subjects: the occupation of clinical services coordinator; interpersonal relationships; ethical/legal aspects; and communications (telephone, intercom, and others). For each…

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

Wu, Tao; Kukkadapu, Ravi K.; Griffin, Aron M.

Fe(III)-oxides and Fe(III)-bearing phyllosilicates are the two major iron sources utilized as electron acceptors by dissimilatory iron-reducing bacteria (DIRB) in anoxic soils and sediments. Although there have been many studies of microbial Fe(III)-oxide and Fe(III)-phyllosilicate reduction with both natural and specimen materials, no controlled experimental information is available on the interaction between these two phases when both are available for microbial reduction. In this study, the model DIRB Geobacter sulfurreducens was used to examine the pathways of Fe(III) reduction in Fe(III)-oxide stripped subsurface sediment that was coated with different amounts of synthetic high surface area goethite. Cryogenic (12K) 57Fe Mössbauermore » spectroscopy was used to determine changes in the relative abundances of Fe(III)-oxide, Fe(III)-phyllosilicate, and phyllosilicate-associated Fe(II) (Fe(II)-phyllosilicate) in bioreduced samples. Analogous Mössbauer analyses were performed on samples from abiotic Fe(II) sorption experiments in which sediments were exposed to a quantity of exogenous soluble Fe(II) (FeCl22H2O) comparable to the amount of Fe(II) produced during microbial reduction. A Fe partitioning model was developed to analyze the fate of Fe(II) and assess the potential for abiotic Fe(II)-catalyzed reduction of Fe(III)-phyllosilicatesilicates. The microbial reduction experiments indicated that although reduction of Fe(III)-oxide accounted for virtually all of the observed bulk Fe(III) reduction activity, there was no significant abiotic electron transfer between oxide-derived Fe(II) and Fe(III)-phyllosilicatesilicates, with 26-87% of biogenic Fe(II) appearing as sorbed Fe(II) in the Fe(II)-phyllosilicate pool. In contrast, the abiotic Fe(II) sorption experiments showed that 41 and 24% of the added Fe(II) engaged in electron transfer to Fe(III)-phyllosilicate surfaces in synthetic goethite-coated and uncoated sediment. Differences in the rate of Fe(II) addition and system redox potential may account for the microbial and abiotic reaction systems. Our experiments provide new insight into pathways for Fe(III) reduction in mixed Fe(III)-oxide/Fe(III)-phyllosilicate assemblages, and provide key mechanistic insight for interpreting microbial reduction experiments and field data from complex natural soils and sediments.« less

Radioactive Cobalt(II) Removal from Aqueous Solutions Using a Reusable Nanocomposite: Kinetic, Isotherms, and Mechanistic Study

PubMed Central

Wang, Ximing; Chen, Zhangjing

2017-01-01

A lignocellulose/montmorillonite (LMT) nanocomposite was prepared as a reusable adsorbent for cobalt(II) ions, and characterized by nitrogen (N2) adsorption/desorption isotherm, X-ray Diffraction (XRD), Scanning Electron Microscope (SEM), Transmission Electron Microscopy (TEM), and Fourier Transform Infrared Spectroscopy (FTIR). LMT exhibited efficient adsorption of cobalt ions (Co(II)), and the adsorbed Co(II) was readily desorbed by nitric acid (HNO3). All parameters affecting the adsorption and/or desorption of Co(II), including initial Co(II) concentration, pH value, temperature, HNO3 concentration, and time, were optimized. The kinetic data analysis showed that the adsorption followed the pseudo-second-order kinetic model and fit well into the Langmuir isotherm equation. Notably, the nanocomposite can be used four times without significantly losing adsorbent capability. The Energy-Dispersive X-ray (EDX) and FTIR spectra analysis also revealed that the adsorption mechanism may be mainly a chemical adsorption dominated process. PMID:29186794

Direct and Electronic Health Record Access to the Clinical Decision Support for Immunizations in the Minnesota Immunization Information System.

PubMed

Rajamani, Sripriya; Bieringer, Aaron; Wallerius, Stephanie; Jensen, Daniel; Winden, Tamara; Muscoplat, Miriam Halstead

2016-01-01

Immunization information systems (IIS) are population-based and confidential computerized systems maintained by public health agencies containing individual data on immunizations from participating health care providers. IIS hold comprehensive vaccination histories given across providers and over time. An important aspect to IIS is the clinical decision support for immunizations (CDSi), consisting of vaccine forecasting algorithms to determine needed immunizations. The study objective was to analyze the CDSi presentation by IIS in Minnesota (Minnesota Immunization Information Connection [MIIC]) through direct access by IIS interface and by access through electronic health records (EHRs) to outline similarities and differences. The immunization data presented were similar across the three systems examined, but with varying ability to integrate data across MIIC and EHR, which impacts immunization data reconciliation. Study findings will lead to better understanding of immunization data display, clinical decision support, and user functionalities with the ultimate goal of promoting IIS CDSi to improve vaccination rates.

Spectral, optical and cytotoxicity studies on 2-isonicotinoyl-N-phenylhydrazine-1-carboxamide(H3L) and some of its metal complexes

NASA Astrophysics Data System (ADS)

Hosny, Nasser M.; Hassan, Nader Y.; Mahmoud, Heba M.; Abdel-Rhman, Mohamed H.

2018-03-01

The ligand 2-isonicotinoyl-N-phenylhydrazine-1-carboxamide (H3L) and its metal complexes with Co(II), Ni(II), Cu(II) and Zn(II) acetates have been synthesized. The isolated compounds have been characterized by elemental analyses, FT-IR, 1H NMR, 13C NMR, ESR, mass, electronic spectra, electrical conductivity, effective magnetic moments and thermal analyses. The free organic ligand exists in the keto form, but in the metal complexes, it coordinates in the enol form. Four coordinated species were suggested for all the isolated metal complexes. The measured optical band gap values confirmed the presence of direct electronic transition and the semi-conductivity of the compounds. The ligand and its Zn(II) complex were examined as cytotoxic agent against HCT-116 and HePG-2. The ligand showed very strong cytotoxic effect against HePG-2, but moderate cytotoxicity against HCT-116. Zn(II) complex showed weak cytotoxicity against the two cell lines.

Synthesis, spectral and thermal studies of some transition metal mixed ligand complexes: Modeling of equilibrium composition and biological activity

NASA Astrophysics Data System (ADS)

Neelakantan, M. A.; Sundaram, M.; Nair, M. Sivasankaran

2011-09-01

Several mixed ligand Ni(II), Cu(II) and Zn(II) complexes of 2-amino-3-hydroxypyridine (AHP) and imidazoles viz., imidazole (him), benzimidazole (bim), histamine (hist) and L-histidine (his) have been synthesized and characterized by elemental and spectral (vibrational, electronic, 1H NMR and EPR) data as well as by magnetic moment values. On the basis of elemental analysis and molar conductance values, all the complexes can be formulated as [MAB]Cl except histidine complexes as MAB. Thermogravimetric studies reveal the presence of coordinated water molecules in most of the complexes. From the magnetic measurements and electronic spectral data, octahedral structure was proposed for Ni(II) and Cu(II)-AHP-his, tetrahedral for Cu(II)-AHP-him/bim/hist, but square planar for the Cu(II)-AHP complex. The g∥/ A∥ calculated supports tetrahedral environment around the Cu(II) in Cu(II)-AHP-him/bim/hist and distorted octahedral for Cu(II)-AHP-his complexes. The morphology of the reported metal complexes was investigated by scanning electron micrographs (SEM). The potentiometric study has been performed in aqueous solution at 37 °C and I = 0.15 mol dm -3 NaClO 4. MABH, MAB and MAB 2 species has been identified in the present systems. Proton dissociation constants of AHP and stability constants of metal complexes were determined using MINIQUAD-75. The most probable structure of the mixed ligand species is discussed based upon their stability constants. The in vitro biological activity of the complexes was tested against the Gram positive and Gram negative bacteria, fungus and yeast. The oxidative DNA cleavage studies of the complexes were performed using gel electrophoresis method. Cu(II) complexes have been found to promote DNA cleavage in presence of biological reductant such as ascorbate and oxidant like hydrogen peroxide.

Cyanide-bridged decanuclear cobalt-iron cage.

PubMed

Shiga, Takuya; Tetsuka, Tamaki; Sakai, Kanae; Sekine, Yoshihiro; Nihei, Masayuki; Newton, Graham N; Oshio, Hiroki

2014-06-16

A cyanide-bridged decanuclear [Co6Fe4] cluster was synthesized by a one-pot reaction, and the magnetic properties and electronic configuration were investigated. The complex displayed thermally controlled electron-transfer-coupled spin transition (ETCST) behavior between Co(III) low-spin-NC-Fe(II) low-spin and Co(II) high-spin-NC-Fe(III) low-spin states, as confirmed by single-crystal X-ray, magnetic, and Mössbauer analyses.

True and masked three-coordinate T-shaped platinum(II) intermediates.

PubMed

Ortuño, Manuel A; Conejero, Salvador; Lledós, Agustí

2013-01-01

Although four-coordinate square-planar geometries, with a formally 16-electron counting, are absolutely dominant in isolated Pt(II) complexes, three-coordinate, 14-electron Pt(II) complexes are believed to be key intermediates in a number of platinum-mediated organometallic transformations. Although very few authenticated three-coordinate Pt(II) complexes have been characterized, a much larger number of complexes can be described as operationally three-coordinate in a kinetic sense. In these compounds, which we have called masked T-shaped complexes, the fourth position is occupied by a very weak ligand (agostic bond, solvent molecule or counteranion), which can be easily displaced. This review summarizes the structural features of the true and masked T-shaped Pt(II) complexes reported so far and describes synthetic strategies employed for their formation. Moreover, recent experimental and theoretical reports are analyzed, which suggest the involvement of such intermediates in reaction mechanisms, particularly C-H bond-activation processes.

Azide derivatized anticancer agents of Vitamin K 3: X-ray structural, DSC, resonance spectral and API studies

NASA Astrophysics Data System (ADS)

Badave, Kirti; Patil, Yogesh; Gonnade, Rajesh; Srinivas, Darbha; Dasgupta, Rajan; Khan, Ayesha; Rane, Sandhya

2011-12-01

Compound 1 [1-imino (acetyl hydrazino)-Vitamin K 3], displays valence tautomerically related electronic isomers as Form I and Form II. Form I exhibits 2D packing fragment with 1D ribbon chains of N-H⋯O hydrogen bonds and shows EPR silent features. While Form II is EPR active and exhibits biradical nature with double quantum transitions at g = 2.0040. 1H NMR of compound 2, [1-imino (hydrazino carboxylate)-Vitamin K 3] and Form II exhibit π delocalization via resonance assisted H-bonding [RAHB] effect compared to Form I. Molecular interactions in Form I and II are visualized by DSC. The electronic structures of compounds 1 and 2 have been correlated to their API values by measuring anticancer activities, mitochondrial potentials and DNA shearing patterns. Form II and compound 2 indicate mitochondria mediated apoptosis (˜75% cell death) while Form I causes 35% cell death.

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

Hoffeditz, William L.; Katz, Michael J.; Deria, Pravas

Dye-sensitized solar cells (DSCs) are an established alternative photovoltaic technology that offers numerous potential advantages in solar energy applications. However, this technology has been limited by the availability of molecular redox couples that are both noncorrosive/nontoxic and do not diminish the performance of the device. In an effort to overcome these shortcomings, a copper-containing redox shuttle derived from 1,8-bis(2'-pyridyl)-3,6-dithiaoctane (PDTO) ligand and the common DSC additive 4-tert-butylpyridine (TBP) was investigated. Electrochemical measurements, single-crystal X-ray diffraction, and absorption and electron paramagnetic resonance spectroscopies reveal that, upon removal of one metal-centered electron, PDTO-enshrouded copper ions completely shed the tetradentate PDTO ligand andmore » replace it with four or more TBP ligands. Thus, the Cu(I) and Cu(II) forms of the electron shuttle have completely different coordination spheres and are characterized by widely differing Cu(II/I) formal potentials and reactivities for forward versus reverse electron transfer. Notably, the coordination-sphere replacement process is fully reversed upon converting Cu(II) back to Cu(I). In cells featuring an adsorbed organic dye and a nano- and mesoparticulate, TiO2-based, photoelectrode, the dual species redox shuttle system engenders performance superior to that obtained with shuttles based on the (II/I) forms of either of the coordination complexes in isolation.« less

Changes in spectrochemical and catalytic properties of biopolymer anchored Cu(II) and Ni(II) catalysts by electron beam irradiation.

PubMed

Antony, R; Suja Pon Mini, P S; Theodore David Manickam, S; Sanjeev, Ganesh; Mitu, Liviu; Balakumar, S

2015-01-01

Chitosan (a biopolymer) anchored Cu(II) and Ni(II) Schiff base complexes, [M(OIAC)Cl2] (M: Cu/Ni and OIAC: ([2-oxo-1H-indol-3-ylidene]amino)chitosan) were electron beam irradiated by different doses (100 Gy, 1 kGy and 10 kGy). The electron beam has shown potential impact on biopolymer's support, in detail chain linking and chain scissoring, as evidenced by viscosity studies, FT-IR and X-ray diffraction spectroscopic techniques. Due to these structural changes, thermal properties of the complexes were found to be changed. The surface of these heterogeneous complexes was also effectually altered by electron beam. As a consequence, pores and holes were created as probed by SEM technique. The catalytic activity of both non-irradiated and irradiated complexes was investigated in the aerobic oxidation of cyclohexane using hydrogen peroxide oxidant. The catalytic ability of the complexes was enhanced significantly after irradiation as the result of surface changes. The reusability of the complexes was also greatly affected because of the structural variations in polymeric support. In terms of both better catalytic activity along with the reusability, 1 kGy is suggested as the best dose to attain adequate increase in catalytic activity and good reusability. Copyright © 2015 Elsevier B.V. All rights reserved.

Intramolecular electron transport in quinoprotein alcohol dehydrogenase of Acetobacter methanolicus: a redox-titration study

PubMed

Frébortova; Matsushita; Arata; Adachi

1998-01-27

Quinohemoprotein-cytochrome c complex alcohol dehydrogenase (ADH) of acetic acid bacteria consists of three subunits, of which subunit I contains pyrroloquinoline quinone (PQQ) and heme c, and subunit II contains three heme c components. The PQQ and heme c components are believed to be involved in the intramolecular electron transfer from ethanol to ubiquinone. To study the intramolecular electron transfer in ADH of Acetobacter methanolicus, the redox potentials of heme c components were determined with ADH complex and the isolated subunits I and II of A. methanolicus, as well as hybrid ADH consisting of the subunit I/III complex of Gluconobacter suboxydans ADH and subunit II of A. methanolicus ADH. The redox potentials of hemes c in ADH complex were -130, 49, 188, and 188 mV at pH 7.0 and 24, 187, 190, and 255 mV at pH 4.5. In hybrid ADH, one of these heme c components was largely changed in the redox potential. Reduced ADH was fully oxidized with potassium ferricyanide, while ubiquinone oxidized the enzyme partially. The results indicate that electrons extracted from ethanol at PQQ site are transferred to ubiquinone via heme c in subunit I and two of the three hemes c in subunit II. Copyright 1998 Elsevier Science B.V.

Non-enzymatic U(VI) interactions with biogenic mackinawite

NASA Astrophysics Data System (ADS)

Veeramani, H.; Qafoku, N. P.; Kukkadapu, R. K.; Murayama, M.; Hochella, M. F.

2011-12-01

Reductive immobilization of hexavalent uranium [U(VI)] by stimulation of dissimilatory metal and/or sulfate reducing bacteria (DMRB or DSRB) has been extensively researched as a remediation strategy for subsurface U(VI) contamination. These bacteria derive energy by reducing oxidized metals as terminal electron acceptors, often utilizing organic substrates as electron donors. Thus, when evaluating the potential for in-situ uranium remediation in heterogeneous subsurface media, it is important to understand how the presence of alternative electron acceptors such as Fe(III) and sulfate affect U(VI) remediation and the long term behavior and reactivity of reduced uranium. Iron, an abundant subsurface element, represents a substantial sink for electrons from DMRB, and the reduction of Fe(III) leads to the formation of dissolved Fe(II) or to reactive biogenic Fe(II)- and mixed Fe(II)/Fe(III)- mineral phases. Consequently, abiotic U(VI) reduction by reactive forms of biogenic Fe(II) minerals could be a potentially important process for uranium immobilization. In our study, the DMRB Shewanella putrefaciens CN32 was used to synthesize a biogenic Fe(II)-bearing sulfide mineral: mackinawite, that has been characterized by XRD, SEM, HRTEM and Mössbauer spectroscopy. Batch experiments involving treated biogenic mackinawite and uranium (50:1 molar ratio) were carried out at room temperature under strict anoxic conditions. Following complete removal of uranium from solution, the biogenic mackinawite was analyzed by a suite of analytical techniques including XAS, HRTEM and Mössbauer spectroscopy to determine the speciation of uranium and investigate concomitant Fe(II)-phase transformation. Determining the speciation of uranium is critical to success of a remediation strategy. The present work elucidates non-enzymatic/abiotic molecular scale redox interactions between biogenic mackinawite and uranium.

Synthesis of Unsupported d(1)-d(x) Oxido-Bridged Heterobimetallic Complexes Containing V(IV): A New Direction for Metal-to-Metal Charge Transfer.

PubMed

Wu, Xinyuan; Huang, Tao; Lekich, Travis T; Sommer, Roger D; Weare, Walter W

2015-06-01

Heterobimetallic complexes composed only of first-row transition metals [(TMTAA)V(IV)═O→M(II)Py5Me2](OTf)2 (TMTAA = 7,16-dihydro-6,8,15,17-tetramethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine; Py5Me2 = 2,6-bis(1,1-bis(2-pyridyl)ethyl)pyridine; M = Mn(II), Fe(II), Co(II), Ni(II), Cu(II); OTf = trifluoromethanesulfonate) have been synthesized through a dative interaction between a terminal oxido and M(II) metal centers. This is the first series of V(IV)═O→M(II) heterobimetallic complexes containing an unsupported oxido bridge. Among these five complexes, only V(IV)═O→Fe(II) (3b) has a clear new absorption band upon formation of the dinuclear species (502 nm, ε = 1700 M(-1) cm(-1)). This feature is assigned to a metal-to-metal charge transfer (MMCT) transition from V(IV) to Fe(II), which forms a V(V)-O-Fe(I) excited state. This assignment is supported by electrochemical data, electronic absorption profiles, and resonance Raman spectroscopy and represents the first report of visible-light induced MMCT in a heterobimetallic oxido-bridged molecule where the electron originates on a d(1) metal center.

Functional role of inorganic trace elements in angiogenesis-Part II: Cr, Si, Zn, Cu, and S.

PubMed

Saghiri, Mohammad Ali; Asatourian, Armen; Orangi, Jafar; Sorenson, Christine M; Sheibani, Nader

2015-10-01

Trace elements play critical roles in angiogenesis events. The effects of nitrogen, iron, selenium, phosphorus, gold, and calcium were discussed in part I. In part II, we evaluated the effect of chromium, silicon, zinc, copper, and sulfur on different aspects of angiogenesis, with critical roles in healing and regeneration processes, and undeniable roles in tumor growth and cancer therapy. This review is the second of series that serves as an overview of the role of inorganic elements in regulation of angiogenesis and vascular function. The methods of exposure, structure, mechanism, and potential activity of these trace elements are briefly discussed. An electronic search was performed on the role of these trace elements in angiogenesis from January 2005 to April 2014. The recent aspects of the relationship between five different trace elements and their role in regulation of angiogenesis, and homeostasis of pro- and anti-angiogenic factors were assessed. Many studies have investigated the effects and importance of these elements in angiogenesis events. Both stimulatory and inhibitory effects on angiogenesis are observed for the evaluated elements. Chromium can promote angiogenesis in pathological manners. Silicon as silica nanoparticles is anti-angiogenic, while in calcium silicate extracts and bioactive silicate glasses promote angiogenesis. Zinc is an anti-angiogenic agent acting on important genes and growth factors. Copper and sulfur compositions have pro-angiogenic functions by activating pro-angiogenic growth factors and promoting endothelial cells migration, growth, and tube formation. Thus, utilization of these elements may provide a unique opportunity to modulate angiogenesis under various setting. Copyright © 2015 Elsevier Ireland Ltd. All rights reserved.

Crystal and electronic structures of magnesium(II), copper(II), and mixed magnesium(II)-copper(II) complexes of the quinoline half of styrylquinoline-type HIV-1 integrase inhibitors.

PubMed

Courcot, B; Firley, D; Fraisse, B; Becker, P; Gillet, J-M; Pattison, P; Chernyshov, D; Sghaier, M; Zouhiri, F; Desmaële, D; d'Angelo, J; Bonhomme, F; Geiger, S; Ghermani, N E

2007-05-31

A new target in AIDS therapy development is HIV-1 integrase (IN). It was proven that HIV-1 IN required divalent metal cations to achieve phosphodiester bond cleavage of DNA. Accordingly, all newly investigated potent IN inhibitors contain chemical fragments possessing a high ability to chelate metal cations. One of the promising leads in the polyhydroxylated styrylquinolines (SQLs) series is (E)-8-hydroxy-2-[2-(4,5-dihydroxy-3-methoxyphenyl)-ethenyl]-7-quinoline carboxylic acid (1). The present study focuses on the quinoline-based progenitor (2), which is actually the most probable chelating part of SQLs. Conventional and synchrotron low-temperature X-ray crystallographic studies were used to investigate the chelating power of progenitor 2. Mg2+ and Cu2+ cations were selected for this purpose, and three types of metal complexes of 2 were obtained: Mg(II) complex (4), Cu(II) complex (5) and mixed Mg(II)-Cu(II) complexes (6 and 7). The analysis of the crystal structure of complex 4 indicates that two tridentate ligands coordinate two Mg2+ cations, both in octahedral geometry. The Mg-Mg distance was found equal to 3.221(1) A, in agreement with the metal-metal distance of 3.9 A encountered in the crystal structure of Escherichia coli DNA polymerase I. In 5, the complex is formed by two bidentate ligands coordinating one copper ion in tetrahedral geometry. Both mixed Mg(II)-Cu(II) complexes, 6 and 7 exhibit an original arrangement of four ligands linked to a central heterometallic cluster consisting of three octahedrally coordinated magnesium ions and one tetrahedrally coordinated copper ion. Quantum mechanics calculations were also carried out in order to display the electrostatic potential generated by the dianionic ligand 2 and complex 4 and to quantify the binding energy (BE) during the formation of the magnesium complex of progenitor 2. A comparison of the binding energies of two hypothetical monometallic Mg(II) complexes with that found in the bimetallic magnesium complex 4 was made.

[Interface bond and compatibility between Mark II machining ceramic and vita VM9 veneering porcelain].

PubMed

Liu, Tian-Shuang; Li, Zhen-Chun; Chen, Xiao-Dong

2009-04-01

To investigate the interface bond and thermal compatibility between Mark II machining ceramic and Vita VM9 veneering porcelain. A bar shaped specimen (30 mm x 15 mm x 1 mm in size) of Mark II block was prepared, with 0.5 mm-deep notch (vertical to the long axis of specimen) at the middle of the bottom surface. The upper surface was veneered with 0.3 mm VM9 dentin base porcelain. Then the specimen was fractured from the notching site and the fracture surface was examined under scanning electron microscope (SEM) and electron microprobe analyzer (EMPA) with electron beam of 1 microm in diameter. Another ten specimens (30 mm x 15 mm x 1.5 mm in size) were fabricated and the temperature of thermal shock resistance were tested. SEM observation showed tight bond between these two materials and EMPA results showed penetration of Al element from Mark II block into veneering porcelain and Ca element from veneering porcelain into Mark II block occurred after sintering baking. The average temperature of thermal shock resistance for specimens in this study was (194.0+/-10.3) degrees C. Cracks were mainly distributed in veneering porcelain. Chemical bond exists between the Mark II machining ceramic and Vita VM9 veneering porcelain, and there is good thermal compatibility between them.

Sphaerotilus natans encrusted with nanoball-shaped Fe(III) oxide minerals formed by nitrate-reducing mixotrophic Fe(II) oxidation

PubMed Central

Park, Sunhwa; Kim, Dong-Hun; Lee, Ji-Hoon; Hur, Hor-Gil

2014-01-01

Ferrous iron has been known to function as an electron source for iron-oxidizing microorganisms in both anoxic and oxic environments. A diversity of bacteria has been known to oxidize both soluble and solid-phase Fe(II) forms coupled to the reduction of nitrate. Here, we show for the first time Fe(II) oxidation by Sphaerotilus natans strain DSM 6575T under mixotrophic condition. Sphaerotilus natans has been known to form a sheath structure enclosing long chains of rod-shaped cells, resulting in a thick biofilm formation under oxic conditions. Here, we also demonstrate that strain DSM 6575T grows mixotrophically with pyruvate, Fe(II) as electron donors and nitrate as an electron acceptor and single cells of strain DSM 6575T are dominant under anoxic conditions. Furthermore, strain DSM 6575T forms nanoball-shaped amorphous Fe(III) oxide minerals encrusting on the cell surfaces through the mixotrophic iron oxidation reaction under anoxic conditions. We propose that cell encrustation results from the indirect Fe(II) oxidation by biogenic nitrite during nitrate reduction and that causes the bacterial morphological change to individual rod-shaped single cells from filamentous sheath structures. This study extends the group of existing microorganisms capable of mixotrophic Fe(II) oxidation by a new strain, S. natans strain DSM 6575T, and could contribute to biogeochemical cycles of Fe and N in the environment. PMID:24965827

Design, synthesis, characterization and cation sensing behavior of amino-naphthoquinone receptor: Selective colorimetric sensing of Cu(II) ion in nearly aqueous solution with mimicking logic gate operation

NASA Astrophysics Data System (ADS)

Parthiban, C.; Elango, Kuppanagounder P.

2017-03-01

An amino-naphthoquione receptor (R1) has been rationally designed, synthesized and characterized using 1H and 13C NMR, LCMS and single crystal X-ray diffraction studies. The receptor exhibits an instantaneous colour change from yellow to blue selectively with Cu(II) ions in water-DMF (98:2% v/v) medium. The results of UV-Vis and fluorescence spectral studies indicates that the mechanism of sensing involves formation of a 1:1 complex between R1 and Cu(II) ion. The proposed mechanism has been confirmed through product analysis using FT-IR, UV-Vis, EPR and HRMS studies in addition to magnetic moment and elemental analysis measurements. The formed [Cu(R1)Cl2] possess a square planar geometry. The binding constant for the interaction of Cu(II) ion with the present unsubstituted quinone is found to be relatively higher than that with quinones containing electron withdrawing chlorine atom and electron releasing methyl group reported in literature. The detection limit of Cu(II) ion in aqueous solution by R1 is observed to be 8.7 nM. The detection of Cu(II) ion by R1 in aqueous solution produces remarkable changes in the electronic and fluorescence spectra, which is applied to construct logic gate at molecular level.

Electron excitation cross sections for the 2s(2)2p(3)4S(O) -- 2s(2)2p(3)2D(O) (forbidden) and 4S(O) -- 2s2p(4) 4P (resonance) transitions in O II

NASA Technical Reports Server (NTRS)

Zuo, M.; Smith, Steven J.; Chutjian, A.; Williams, I. D.; Tayal, S. S.; Mclaughlin, Brendan M.

1995-01-01

Experimental and theoretical excitation cross sections are reported for the first forbidden transition 4S(O) -- 2S(2)2p(3) 2D(O) (lambda-lambda 3726, 3729) and the first allowed (resonance) transition 4S(O) -- 2s2p(4) 4P(lambda-833) in O II. Use is made of electron energy loss and merged-beams methods. The electron energy range covered is 3.33 (threshold) to 15 eV for the S -- D transition, and 14.9 (threshold) to 40 eV for the S -- P transition. Care was taken to assess and minimize the metastable fraction of the O II beam. An electron mirror was designed and tested to reflect inelastically backscattered electrons into the forward direction to account for the full range of polar scattering angles. Comparisons are made between present experiments and 11-state R-matrix calculations. Calculations are also presented for the 4S(O) -- 2s(2)2p(3)2P(O) (lambda-2470) transition.

A process model for the heat-affected zone microstructure evolution in duplex stainless steel weldments: Part II. Application to electron beam welding

NASA Astrophysics Data System (ADS)

Hemmer, H.; Grong, Ø.; Klokkehaug, S.

2000-03-01

In the present investigation, a process model for electron beam (EB) welding of different grades of duplex stainless steels (i.e. SAF 2205 and 2507) has been developed. A number of attractive features are built into the original finite element code, including (1) a separate module for prediction of the penetration depth and distribution of the heat source into the plate, (2) adaptive refinement of the three-dimensional (3-D) element mesh for quick and reliable solution of the differential heat flow equation, and (3) special subroutines for calculation of the heat-affected zone (HAZ) microstructure evolution. The process model has been validated by comparison with experimental data obtained from in situ thermocouple measurements and optical microscope examinations. Subsequently, its aptness to alloy design and optimization of welding conditions for duplex stainless steels is illustrated in different numerical examples and case studies pertaining to EB welding of tubular joints.

Full-color laser cathode ray tube (L-CRT) projector

NASA Astrophysics Data System (ADS)

Kozlovskiy, Vladimir; Nasibov, Alexander S.; Popov, Yuri M.; Reznikov, Parvel V.; Skasyrsky, Yan K.

1995-04-01

A full color TV projector based on three laser cathode-ray tubes (L-CRT) is described. A water-cooled laser screen (LS) is the radiation element of the L-CRT. We have produced three main colors (blue, green and red) by using the LS made of three II-VI compounds: ZnSe ((lambda) equals 475 nm), CdS ((lambda) equals 530 nm) and ZnCdSe (630 nm). The total light flow reaches 1500 Lm, and the number of elements per line is not less than 1000. The LS efficiency may be about 10 Lm/W. In our experiments we have tested new electron optics: - (30 - 37) kV are applied to the cathode unit of the electron gun; the anode of the e-gun and the e-beam intensity modulator are under low potential; the LS has a potential + (30 - 37) kV. The accelerating voltage is divided into two parts, and this enables us to diminish the size and weight of the projector.

Emergence of californium as the second transitional element in the actinide series

DOE PAGES

Cary, Samantha K.; Vasiliu, Monica; Baumbach, Ryan E.; ...

2015-04-16

A break in periodicity occurs in the actinide series between plutonium and americium as the result of the localization of 5f electrons. The subsequent chemistry of later actinides is thought to closely parallel lanthanides in that bonding is expected to be ionic and complexation should not substantially alter the electronic structure of the metal ions. Here we demonstrate that ligation of californium(III) by a pyridine derivative results in significant deviations in the properties of the resultant complex with respect to that predicted for the free ion. We expand on this by characterizing the americium and curium analogues for comparison, andmore » show that these pronounced effects result from a second transition in periodicity in the actinide series that occurs, in part, because of the stabilization of the divalent oxidation state. As a result, the metastability of californium(II) is responsible for many of the unusual properties of californium including the green photoluminescence.« less

Identification of Zn vacancies in ZnTe doped with Cl and I

NASA Astrophysics Data System (ADS)

Asoka-Kumar, Palakkal; Alatalo, Matti; Wang, Wen

1997-03-01

The doping difficulties of II-VI semiconductors are well known. For example, ZnTe can be doped easily to have p-type conductivity but not n-type. We examined Cl and I doped ZnTe using positron annihilation spectroscopy to understand the role of vacancies in the compensation mechanism. The annihilation line shapes from inner-shell electrons can be used for elemental identification[1]. Results from ZnTe:Cl and ZnTe:I show an enhancement of annihilations with Te electrons compared to undoped samples, and is explained as arising due to first neighbor of a Zn vacancy. Theoretical calculations of the annihilation line shapes from bulk ZnTe and Zn and Te vacancies will also be presented. This work was supported in part by the US DOE under contract No. DE-AC02-76CH00016. [1] P. Asoka-Kumar, M. Alatalo, V.J. Ghosh, A.C. Kruseman, B. Nielsen, and K.G. Lynn, Phys. Rev. Lett. Vol. 77, 2097 (1996).

Influence of the variation potential on photosynthetic flows of light energy and electrons in pea.

PubMed

Sukhova, Ekaterina; Mudrilov, Maxim; Vodeneev, Vladimir; Sukhov, Vladimir

2018-05-01

Local damage (mainly burning, heating, and mechanical wounding) induces propagation of electrical signals, namely, variation potentials, which are important signals during the life of plants that regulate different physiological processes, including photosynthesis. It is known that the variation potential decreases the rate of CO 2 assimilation by the Calvin-Benson cycle; however, its influence on light reactions has been poorly investigated. The aim of our work was to investigate the influence of the variation potential on the light energy flow that is absorbed, trapped and dissipated per active reaction centre in photosystem II and on the flow of electrons through the chloroplast electron transport chain. We analysed chlorophyll fluorescence in pea leaves using JIP-test and PAM-fluorometry; we also investigated delayed fluorescence. The electrical signals were registered using extracellular electrodes. We showed that the burning-induced variation potential stimulated a nonphotochemical loss of energy in photosystem II under dark conditions. It was also shown that the variation potential gradually increased the flow of light energy absorbed, trapped and dissipated by photosystem II. These changes were likely caused by an increase in the fraction of absorbed light distributed to photosystem II. In addition, the variation potential induced a transient increase in electron flow through the photosynthetic electron transport chain. Some probable mechanisms for the influence of the variation potential on the light reactions of photosynthesis (including the potential role of intracellular pH decrease) are discussed in the work.

NASA Parts Selection List (NPSL) WWW Site http://nepp.nasa.gov/npsl

NASA Technical Reports Server (NTRS)

Brusse, Jay

2000-01-01

The NASA Parts Selection List (NPSL) is an on-line resource for electronic parts selection tailored for use by spaceflight projects. The NPSL provides a list of commonly used electronic parts that have a history of satisfactory use in spaceflight applications. The objective of this www site is to provide NASA projects, contractors, university experimenters, et al with an easy to use resource that provides a baseline of electronic parts from which designers are encouraged to select. The NPSL is an ongoing resource produced by Code 562 in support of the NASA HQ funded NASA Electronic Parts and Packaging (NEPP) Program. The NPSL is produced as an electronic format deliverable made available via the referenced www site administered by Code 562. The NPSL does not provide information pertaining to patented or proprietary information. All of the information contained in the NPSL is available through various other public domain resources such as US Military procurement specifications for electronic parts, NASA GSFC's Preferred Parts List (PPL-21), and NASA's Standard Parts List (MIL-STD975).

Anoxygenic growth of cyanobacteria on Fe(II) and their associated biosignatures: Implications for biotic contributions to Precambrian Banded Iron Formations

NASA Astrophysics Data System (ADS)

Parenteau, M.; Jahnke, L. L.; Cady, S. L.; Pierson, B.

2011-12-01

Banded Iron Formations (BIFs) are widespread Precambrian sedimentary deposits that accumulated in deep ocean basins or shallow platformal areas with inputs of reduced iron (Fe(II)) and silica from deep ocean hydrothermal activity. There is debate as to whether abiotic or biotic mechanisms were responsible for the oxidation of aqueous Fe(II) and the subsequent accumulation of ferric iron (Fe(III)) mineral assemblages in BIFs. Biotic Fe(II) oxidation could have occurred indirectly as a result of the photosynthetic production of oxygen by cyanobacteria, or could have been directly mediated by anoxygenic phototrophs or chemolithotrophs. The anoxygenic use of Fe(II) as an electron donor for photosynthesis has also been hypothesized in cyanobacteria, representing another biotic mechanism by which Fe(II) could be oxidized in BIFs. This type of photoferrotrophic metabolism may also represent a key step in the evolution of oxygenic photosynthesis. Members of our group have speculated that an intermediate reductant such as Fe(II) could have acted as a transitional electron donor before water. The widespread abundance of Fe(II) in Archean and Neoproterozoic ferruginous oceans would have made it particularly suitable as an electron donor for photosynthesis. We have been searching for modern descendants of such an ancestral "missing link" cyanobacterium in the phototrophic mats at Chocolate Pots, a hot spring in Yellowstone National Park with a constant outflow of anoxic Fe(II)-rich thermal water. Our physiological ecology study of the Synechococcus-Chloroflexi mat using C-14 bicarbonate uptake and autoradiography experiments revealed that the cyanobacteria grow anoxygenically using Fe(II) as an electron donor for photosynthesis in situ. An initial set of similar experiments substituting C-13 bicarbonate as the tracer was used to characterize labeling of the community lipid biomarker signature and confirm the C-14 results. Under light conditions with and without Fe(II), the C-13 label was greatly enriched in the cyanobacterial lipid biomarker n-heptadecane, while dark controls showed no incorporation. No significant incorporation was noted in the Chloroflexi lipid biomarker wax esters, suggesting that Chloroflexus and Roseiflexus grow as photoheterotrophs in these mats. A complimentary study of the microbial biosignatures produced in these mats revealed iron-permineralized carbonaceous microfossils of the candidate photoferrotrophs. Diagnostic lipid biomarkers of the cyanobacteria included n-heptadecane, mid-chain branched mono- and dimethyl analogs and, most notably, 2-methylhopanoids. Wax esters and a long chain tri-unsaturated alkene were proxies for the Chloroflexi. Our work has for the first time identified 2-methylhopanoids in a modern iron-mineralized cyanobacterial mat where the cyanobacteria have been shown to grow anoxygenically using Fe(II) as an electron donor for photosynthesis. We are also currently screening the JGI Yellowstone Community Sequencing Project metagenomic data from this mat for the molecular basis of this type of photoferrotrophic metabolism.

Review on health effects related to mobile phones. Part II: results and conclusions.

PubMed

Moussa, Mayada M R

2011-01-01

Part 1 of this review was published in the Journal of Egyptian Association of Public Health 2010; 85(5, 6):337-345. It included the introduction and methodology. It was based on reviewing the literature published in the last 10 years (2000-2010). Searches were made electronically through various search engines and health-related databases, and manually through journals, reports, and conference proceedings. The references used in the introduction of part 1 were mainly WHO reports, textbooks, and nonserial publications. In part 2, the literature published in 2011 was added to the yield and the results and conclusions are based on the updated search. In this literature search, 69 research articles (epidemiologic, experimental, cellular, and animal studies), 17 systemic or meta-analysis review studies, and four reports were included. The evidence presented in these peer-reviewed publications did not provide a consistent pattern that exposure to mobile phones is detrimental to health. Only studies associating mobile phone use during driving with road traffic accidents and those investigating electromagnetic interference with personal or hospital medical electronic devices showed consistent results. Regarding children, there are currently little data on cell phone use and health effects, including the risk of cancer. Further experimental and epidemiologic studies are needed to seek explanations for the controversies in studies on mobile phones so far. These studies should apply sound methodology for exposure assessment of mobile phone radiation and should focus on the effects of long-term use (more than 10 years). Cohort studies, in particular, should be established to investigate the long-term effects of mobile phone use on brain cancer as well as to investigate the possible health effects among children.

Gunshot residue testing in suicides: Part I: Analysis by scanning electron microscopy with energy-dispersive X-ray.

PubMed

Molina, D Kimberley; Martinez, Michael; Garcia, James; DiMaio, Vincent J M

2007-09-01

Several different methods can be employed to test for gunshot residue (GSR) on a deceased person's hands, including scanning electron microscopy with energy-dispersive x-ray spectroscopy (SEM-EDX) and inductively coupled plasma-atomic emission spectrometry (ICP-AES). Each of these techniques has been extensively studied, especially on living individuals. The current studies (Part I and Part II) were designed to compare the use and utility of the different GSR testing techniques in a medical examiner setting. In Part I, the hands of deceased persons who died from undisputed suicidal handgun wounds were tested for GSR by SEM-EDX over a 4-year period. A total of 116 cases were studied and analyzed for caliber of weapon, proximity of wound, and results of GSR testing, including spatial deposition upon the hands. It was found that in only 50% of cases with a known self-inflicted gunshot wound was SEM-EDX positive for at least 1 specific particle for GSR. In 18% of the cases there was a discernible pattern (spatial distribution) of the particles on the hand such that the manner in which the weapon was held could be determined. Since only 50% of cases where the person is known to have fired a weapon immediately prior to death were positive for GSR by SEM-EDX, this test should not be relied upon to determine whether a deceased individual has discharged a firearm. Furthermore, in only 18% of cases was a discernible pattern present indicating how the firearm was held. The low sensitivity, along with the low percentage of cases with a discernible pattern, limits the usefulness of GSR test results by SEM-EDX in differentiating self-inflicted from non-self-inflicted wounds.

Electronic Equipment Reliability Data,

DTIC Science & Technology

1986-04-02

MTBF RELATIONSHIPS 2- 60 (INDEPENDENT OF PREDICTED MTBF) vii LIST OF FIGURES Page FIGURE 1: CONTROLS/DISPLAYS FIELD MTBF VERSUS PREDICTED MTBF 2-9 FIGURE...LJ LO C-.. c’J - - IL D LLLJ c c 1,P, 4-) CD ui on LU V)4-> LD 2 2- 60 field maintenance data (MTBMAFIELD) and observed field failure data (MTBFFIELD...w N w DLM I_, II II uh II |II II II II L II II it 00I II I-. m . LI I I I I I I I I I I I I- - - - - I I I I I I I Of m- I C II ~ 1 1 10 0 0 0 01 1 1

The NASA Electronic Parts and Packaging (NEPP) Program: NEPP Overview - Automotive Electronics

NASA Technical Reports Server (NTRS)

LaBel, Kenneth A.; Sampson, Michael J.

2016-01-01

The results of NASAs studies into the appropriateness of using U.S. Automotive electronic parts in NASA spaceflight systems will be presented. The first part of the presentation provides an overview of the United States Automotive Electronics Council's AECQ standardization program, the second part provides a summary of the results of NASA's procurement and testing experiences and other lessons learned along with preliminary test results.

Voyager electronic parts radiation program. Volume 2: Test requirements and procedures

NASA Technical Reports Server (NTRS)

Stanley, A. G.; Martin, K. E.; Price, W. E.

1978-01-01

Documents are presented outlining the conditions and requirements of the test program. The Appendixes are as follows: appendix A -- Electron Simulation Radiation Test Specification for Voyager Electronic Parts and Devices, appendix B -- Electronic Piece-Part Testing Program for Voyager, appendix C -- Test Procedure for Radiation Screening of Voyager Piece Parts, appendix D -- Boeing In Situ Test Fixture, and appendix E -- Irradiate - Anneal (IRAN) Screening Documents.

On the Presentation of Wave Phenomena of Electrons with the Young-Feynman Experiment

ERIC Educational Resources Information Center

Matteucci, Giorgio

2011-01-01

The Young-Feynman two-hole interferometer is widely used to present electron wave-particle duality and, in particular, the buildup of interference fringes with single electrons. The teaching approach consists of two steps: (i) electrons come through only one hole but diffraction effects are disregarded and (ii) electrons come through both holes…

Evaluation of estimated energy conservation measure costs and benefits in the residential multifamily sector

NASA Astrophysics Data System (ADS)

1982-09-01

Supporting data for a policy review to determine how the multifamily buildings subsector is responding to market signals was sought. What role, if any, the federal government should play in encouraging conservation in multifamily buildings is discussed. The policy review seeks to develop an understanding of the current level of and trends in energy conservation activity in multifamily housing. The availability of the required data is determined and information in a form which facilitates its use by policy analysts is compiled. The results are presented in four parts. Part I provides an overview. Part II presents, in tabular form, the cost of selected retrofit items and the resulting energy and cost savings. As an aid to understanding the data in Part II, the salient assumptions underlying the data are also included in this part. Part III describes how the data in Part II were developed.

40 CFR Table II-1 to Subpart II of... - Emission Factors

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 21 2014-07-01 2014-07-01 false Emission Factors II Table II-1 to Subpart II of Part 98 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Industrial Wastewater Treatment Pt. 98, Subpt. II, Table II-1...

40 CFR Table II-1 to Subpart II of... - Emission Factors

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 22 2013-07-01 2013-07-01 false Emission Factors II Table II-1 to Subpart II of Part 98 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) AIR PROGRAMS (CONTINUED) MANDATORY GREENHOUSE GAS REPORTING Industrial Wastewater Treatment Pt. 98, Subpt. II, Table II-1...

42 CFR 423.509 - Termination of contract by CMS.

Code of Federal Regulations, 2012 CFR

2012-10-01

... Part D plan in writing 90 days before the intended date of the termination. (ii) The Part D plan... sponsor; (B) The Part D plan sponsor experiences financial difficulties so severe that its ability to make...)(4) of this section. (ii) CMS notifies the MA organization in writing that its contract will be...

5 CFR 330.602 - Definitions.

Code of Federal Regulations, 2012 CFR

2012-01-01

... equivalent) or below who: (i) Received a reduction in force (RIF) separation notice under part 351 of this... positions; and (ii) Received a RIF separation notice under part 351 of this chapter or a notice of proposed...); or (ii) Received a RIF notice of separation under part 351 of this chapter or a notice of proposed...

5 CFR 330.602 - Definitions.

Code of Federal Regulations, 2013 CFR

2013-01-01

... equivalent) or below who: (i) Received a reduction in force (RIF) separation notice under part 351 of this... positions; and (ii) Received a RIF separation notice under part 351 of this chapter or a notice of proposed...); or (ii) Received a RIF notice of separation under part 351 of this chapter or a notice of proposed...

5 CFR 330.602 - Definitions.

Code of Federal Regulations, 2014 CFR

2014-01-01

... equivalent) or below who: (i) Received a reduction in force (RIF) separation notice under part 351 of this... positions; and (ii) Received a RIF separation notice under part 351 of this chapter or a notice of proposed...); or (ii) Received a RIF notice of separation under part 351 of this chapter or a notice of proposed...

Market Analysis and Consumer Impacts Source Document. Part II. Review of Motor Vehicle Market and Consumer Expenditures on Motor Vehicle Transportation

DOT National Transportation Integrated Search

1980-12-01

This source document on motor vehicle market analysis and consumer impacts consists of three parts. Part II consists of studies and review on: motor vehicle sales trends; motor vehicle fleet life and fleet composition; car buying patterns of the busi...

Calculus of Elementary Functions, Part II. Teacher's Commentary. Revised Edition.

ERIC Educational Resources Information Center

Herriot, Sarah T.; And Others

This course is intended for students who have a thorough knowledge of college preparatory mathematics, including algebra, axiomatic geometry, trigonometry, and analytic geometry. This teacher's guide is for Part II of the course. It is designed to follow Part I of the text. The guide contains background information, suggested instructional…

Calculus of Elementary Functions, Part II. Student Text. Revised Edition.

ERIC Educational Resources Information Center

Herriot, Sarah T.; And Others

This course is intended for students who have a thorough knowledge of college preparatory mathematics, including algebra, axiomatic geometry, trigonometry, and analytic geometry. This text, Part II, contains material designed to follow Part I. Chapters included in this text are: (6) Derivatives of Exponential and Related Functions; (7) Area and…

NSLS-II Preliminary Design Report

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

Dierker, S.

2007-11-01

Following the CD0 approval of the National Synchrotron Light Source II (NSLS-II) during August 2005, Brookhaven National Laboratory prepared a conceptual design for a worldclass user facility for scientific research using synchrotron radiation. DOE SC review of the preliminary baseline in December 2006 led to the subsequent CD1 approval (approval of alternative selection and cost range). This report is the documentation of the preliminary design work for the NSLS-II facility. The preliminary design of the Accelerator Systems (Part 1) was developed mostly based of the Conceptual Design Report, except for the Booster design, which was changed from in-storage-ring tunnel configurationmore » to in external- tunnel configuration. The design of beamlines (Part 2) is based on designs developed by engineering firms in accordance with the specification provided by the Project. The conventional facility design (Part 3) is the Title 1 preliminary design by the AE firm that met the NSLS-II requirements. Last and very important, Part 4 documents the ES&H design and considerations related to this preliminary design. The NSLS-II performance goals are motivated by the recognition that major advances in many important technology problems will require scientific breakthroughs in developing new materials with advanced properties. Achieving this will require the development of new tools that will enable the characterization of the atomic and electronic structure, chemical composition, and magnetic properties of materials, at nanoscale resolution. These tools must be nondestructive, to image and characterize buried structures and interfaces, and they must operate in a wide range of temperatures and harsh environments. The NSLS-II facility will provide ultra high brightness and flux and exceptional beam stability. It will also provide advanced insertion devices, optics, detectors, and robotics, and a suite of scientific instruments designed to maximize the scientific output of the facility. Together these will enable the study of material properties and functions with a spatial resolution of {approx}1 nm, an energy resolution of {approx}0.1 meV, and the ultra high sensitivity required to perform spectroscopy on a single atom. In order to meet this need, NSLS-II has been designed to provide world-leading brightness and flux and exceptional beam stability. The brightness is defined as the number of photons emitted per second, per photon energy bandwidth, per solid angle, and per unit source size. Brightness is important because it determines how efficiently an intense flux of photons can be refocused to a small spot size and a small divergence. It scales as the ring current and the number of total periods of the undulator field (both of which contribute linearly to the total flux), as well as eing nversely proportional to the horizontal and vertical emittances (the product of beam size and divergence) of the electron beam. Raising the current in the storage ring to obtain even brighter beams is ultimately limited by beam-driven, collective instabilities in the accelerator. Thus, to maximize the brightness, the horizontal and vertical emittances must be made as small as possible. With the concept of using damping wigglers, low-field bending magnets, and a large number of lattice cells to achieve ultra small emittance, the performance of NSLS-II will be nearly at the ultimate limit of storage ring light sources, set by the intrinsic properties of the synchrotron radiation process. The facility will produce x-rays more than 10,000 times brighter than those produced at NSLS today. The facility, with various insertion devices, including three-pole-wigglers and low-field dipole radiations, has the capability of covering a broad range of radiation spectra, from hard x-ray to far infra-red. The superlative character and combination of capabilities will have broad impact on a wide range of disciplines and scientific initiatives in the coming decades, including new studies of small crystals in structural biology, a wide range of nanometer-resolution probes for nanoscience, coherent imaging of the structure and dynamics of disordered materials, greatly increased applicability of inelastic x-ray scattering, and properties of materials under extreme conditions. Commissioned in 1982, the existing National Synchrotron Light Source (NSLS) provides essential scientific tools for 2,300 scientists per year from more than 400 academic, industrial, and government institutions. Their myriad research programs produce about 800 publications per year, with more than 130 appearing in premier journals. It was designed in the 1970s and is now in its third decade of service. It has been continually upgraded over the years, with the brightness increasing fully five orders of magnitude. However, it has reached the theoretical limits of performance given its small circumference and small periodicity, and only a small number of insertion devices are possible.« less

The ETA-II linear induction accelerator and IMP wiggler: A high-average-power millimeter-wave free-electron-laser for plasma heating

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

Allen, S.L.; Scharlemann, E.T.

1992-05-01

We have constructed a 140-GHz free-electron laser to generate high-average-power microwaves for heating the MTX tokamak plasma. A 5.5-m steady-state wiggler (intense Microwave Prototype-IMP) has been installed at the end of the upgraded 60-cell ETA-II accelerator, and is configured as an FEL amplifier for the output of a 140-GHz long-pulse gyrotron. Improvements in the ETA-II accelerator include a multicable-feed power distribution network, better magnetic alignment using a stretched-wire alignment technique (SWAT). and a computerized tuning algorithm that directly minimizes the transverse sweep (corkscrew motion) of the electron beam. The upgrades were first tested on the 20-cell, 3-MeV front end ofmore » ETA-II and resulted in greatly improved energy flatness and reduced corkscrew motion. The upgrades were then incorporated into the full 60-cell configuration of ETA-II, along with modifications to allow operation in 50-pulse bursts at pulse repetition frequencies up to 5 kHz. The pulse power modifications were developed and tested on the High Average Power Test Stand (HAPTS), and have significantly reduced the voltage and timing jitter of the MAG 1D magnetic pulse compressors. The 2-3 kA. 6-7 MeV beam from ETA-II is transported to the IMP wiggler, which has been reconfigured as a laced wiggler, with both permanent magnets and electromagnets, for high magnetic field operation. Tapering of the wiggler magnetic field is completely computer controlled and can be optimized based on the output power. The microwaves from the FEL are transmitted to the MTX tokamak by a windowless quasi-optical microwave transmission system. Experiments at MTX are focused on studies of electron-cyclotron-resonance heating (ECRH) of the plasma. We summarize here the accelerator and pulse power modifications, and describe the status of ETA-II, IMP, and MTX operations.« less