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Sample records for acid 4-x c6h4no2

  1. Preparation and physical properties of (PVA0.7(NaBr0.3(H3PO4xM solid acid membrane for phosphoric acid – Fuel cells

    F. Ahmad

    2013-03-01

    Full Text Available A solid acid membranes based on poly (vinyl alcohol (PVA, sodium bromide (NaBr and phosphoric acid (H3PO4 were prepared by a solution casting method. The morphological, IR, electrical and optical properties of the (PVA0.7(NaBr0.3(H3PO4xM solid acid membranes where x = 0.00, 0.85, 1.7, 3.4, 5.1 M were investigated. The variation of film morphology was examined by scanning electron microscopy (SEM studies. FTIR spectroscopy has been used to characterize the structure of polymer and confirms the complexation of phosphoric acid with host polymeric matrix. The temperature dependent nature of ionic conductivity and the impedance of the polymer electrolytes were determined along with the associated activation energy. The ionic conductivity at room temperature was found to be strongly depends on the H3PO4 concentration which it has been achieved to be of the order 4.3 × 10−3 S/cm at ambient temperature. Optical measurements showed a decrease in optical band gap and an increase in band tail width with the increase of phosphoric acid. The data shows that the (PVA0.7(NaBr0.3(H3PO4xM solid acid membrane is promising for intermediate temperature phosphoric acid fuel cell applications.

  2. Bimodal cesium hydrogen salts of 12-tungstosilicic acid, CsxH4-xSiW12O40, as highly active solid acid catalysts for transesterification of glycerol tributyrate with methanol

    Iwase, Yukari; Sano, Shogo; Mahardiani, Lina; Abe, Ryu; Kamiya, Yuichi

    2014-01-01

    Bimodal CsxH4-x[SiW12O40] (Csx-bimodal) with mesopores interconnected with micropores were synthesized from microporous CsxH4-x[SiW12O40 (Csx-micro) with x = 1.0-2.5, which were prepared in advance by titrating an aqueous solution of H-4[SiW12O40] with an aqueous solution of Cs2CO3, followed by treatment in refluxing ethanol to mainly dissolve the H-4[SiW12O40] in the particles. Mesopore size distributions and their pore volumes changed depending on x in Csx-micro. Microporous Cs2.5-micro tra...

  3. Synthesis and Electrochemical Performance of Spinel LiMn2O4-x(SO4)x Cathode Materials

    CHEN,Zhao-Yong(陈召勇); HE,Yi(贺益); LI,Zhi-Jie(李志杰); GAO,Li-Zhen(高利珍); JIANG,Qi(江奇); YU,Zuo-Long(于作龙)

    2002-01-01

    The spinel LiMn2O4-x(SO4)x compound cathode materials were synthesized by solid-state reaction of the calculated amounts of LiOH@H2O,MnO2 and MnSO4.The results of the electrochemical test demonstrated that these materials exhibited excellent electrochemical properties.The highest reversible capacity of these series of cathode materials was~120mAh/g,and after 50 cycles,this reversible capacity was still around 116 mAh/g with nearly 100% reversible efficiency,which revealed that doped sulfate ion could improve the structural stability of spinel.

  4. Optimization of Fuzzy Matrix Games of Order 4 X 3

    R. Senthil Kumar

    2014-10-01

    Full Text Available In this paper, we consider a solution for Fuzzy matrix game with fuzzy pay offs. The Solution of Fuzzy matrix games with pure strategies with maximin – minimax principle is discussed. A method takes advantage of the relationship between fuzzy sets and fuzzy matrix game theories can be offered for multicriteria decision making. Here, m x n pay off matrix is reduced to 4 x 3 pay off matrix.

  5. Optimization of Fuzzy Matrix Games of Order 4 X 3

    R. Senthil Kumar; S. Kumaraghuru

    2014-01-01

    In this paper, we consider a solution for Fuzzy matrix game with fuzzy pay offs. The Solution of Fuzzy matrix games with pure strategies with maximin – minimax principle is discussed. A method takes advantage of the relationship between fuzzy sets and fuzzy matrix game theories can be offered for multicriteria decision making. Here, m x n pay off matrix is reduced to 4 x 3 pay off matrix.

  6. An A4 x Z4 model for neutrino mixing

    BenTov, Yoni; Zee, A

    2012-01-01

    The A4 x U(1) flavor model of He, Keum, and Volkas is extended to provide a minimal modification to tribimaximal mixing that accommodates a nonzero reactor angle theta13 ~ 0.1. The sequestering problem is circumvented by forbidding superheavy scales and large coupling constants which would otherwise generate sizable RG flows. The model is compatible with (but does not require) a stable or metastable dark matter candidate in the form of a complex scalar field with unit charge under a discrete subgroup Z4 of the U(1) flavor symmetry.

  7. Cost comparison of 4x500 MW coal-fuelled and 4x850 MW CANDU nuclear generating stations

    The lifetime costs for a 4x850 MW CANDU generating station are compared to those for 4x500 MW bituminous coal-fuelled generating stations. Two types of coal-fuelled stations are considered; one burning U.S. coal which includes flue gas desulfurization and one burning Western Canadian coal. Current estimates for the capital costs, operation and maintenance costs, fuel costs, decommissioning costs and irradiated fuel management costs are shown. The results show: (1) The accumulated discounted costs of nuclear generation, although initially higher, are lower than coal-fuelled generation after two or three years. (2) Fuel costs provide the major contribution to the total lifetime costs for coal-fuelled stations whereas capital costs are the major item for the nuclear station. (3) The break even lifetime capacity factor between nuclear and U.S. coal-fuelled generation is projected to be 5%; that for nuclear and Canadian coal-fuelled generation is projected to be 9%. (4) Large variations in the costs are required before the cost advantage of nuclear generation is lost. (5) Comparison with previous results shows that the nuclear alternative has a greater cost advantage in the current assessment. (6) The total unit energy cost remains approximately constant throughout the station life for nuclear generation while that for coal-fuelled generation increases significantly due to escalating fuel costs. The 1978 and 1979 actual total unit energy cost to the consumer for several Ontario Hydro stations are detailed, and projected total unit energy costs for several Ontario Hydro stations are shown in terms of escalated dollars and in 1980 constant dollars

  8. Tuning frustrated antiferromagnetism in intermetallic AFe4X2 systems

    Magnetic systems with reduced dimensionality or frustration are attracting strong interest because these features lead to an increase of quantum fluctuations which often results in unusual, very interesting properties. Here we present a detailed study of the intermetallic AFe4X2 compounds (A=Sc,Y,Lu,Zr; X=Si,Ge) crystallizing in the ZrFe4Si2 structure type in which the Fe-sublattice is formed by chains of edge-linked tetrahedra. We synthesized polycrystalline samples of all these compounds and investigated their magnetic, thermodynamic, structural and transport properties. Our results indeed evidence this family of compounds to cover the whole regime from frustrated antiferromagnetic (AFM) order up to the quantum critical point separating the AFM ground state from the paramagnetic ground state. All compounds with trivalent A elements show frustrated AFM order. Replacement of trivalent A by tetravalent Zr shifts the system towards an unstable magnetic state. Since YFe4Si2 and ZrFe4Si2 present peculiar features, we also studied the influence of different annealing conditions and slight off-stoichiometry on their unusual properties.

  9. X-ray diffraction investigation of the sulphur induced 4x1 reconstruction of Ni(110)

    Foss, M.; Feidenhans'l, R.; Nielsen, M.; Findeisen, E.; Buslaps, T.; Johnson, R.L.; Besenbacher, F.; Stensgaard, I.

    1993-01-01

    The atomic structure of the Ni(110)4 x 1-S reconstruction has been determined on the basis of surface X-ray diffraction measurements. An analysis of the in-plane diffraction data shows that the model consists of Ni rows along the [001] direction, two for every 4 x 1 unit cell, corresponding to 0...

  10. Approaching Minimal Flavour Violation from an S4 x SU(5) SUSY GUT

    Dimou, Maria; Luhn, Christoph

    2015-01-01

    We show how approximate Minimal Flavour Violation (MFV) can emerge from an SU(5) Supersymmetric Grand Unified Theory (SUSY GUT) supplemented by an S4 x U(1) family symmetry, which provides a good description of all quark and lepton (including neutrino) masses, mixings and CP violation. Assuming a SUSY breaking mechanism which respects the family symmetry, we calculate in full explicit detail the low energy mass insertion parameters in the super-CKM basis, including the effects of canonical normalisation and renormalisation group running. We find that the very simple family symmetry S4 x U(1) is sufficient to approximately reproduce the effects of low energy MFV.

  11. Synthesis of CoxNi1-XFe2o4 (X = 0.0, 0.5, 1.0) Nanoparticles by Chemical Co-Precipitation Route

    Maaz, K; Ihsan A; Fatima I

    2014-01-01

    Magnetic nanoparticles (NPs) of nickel-cobalt ferrite (CoxNi1-xFe2O4; x = 0.0, 0.5, 1.0) were synthesized by co-precipitation route. The chemicals used were nickel chloride, cobalt chloride, ferric chloride, sodium hydroxide, and oleic acid. Sodium hydroxide was used as the precipitating agent and oleic acid was used as the surfactant. X-ray diffraction (XRD) analysis confirmed the formation of single phase nickel-cobalt ferrite nanoparticles in the size range 12-20 nm. The obt...

  12. 2-Methoxycarbonylpyridinium tetrachlorido(pyridine-2-carboxylato-κ2N,Ostannate(IV

    Ezzatollah Najafi

    2011-02-01

    Full Text Available In the reaction of pyridine-2-carboxylic acid and stannic chloride in methanol, one equivalent of the carboxylic acid is protonated at the amino site and is also esterified, yielding the title salt, (C7H8NO2[SnCl4(C6H4NO2]. The SnIV atom in the anion is N,O-chelated by a pyridine-2-carboxylate in a cis-SnNOCl4 octahedral geometry. The cation is linked to the anion by an N—H...O hydrogen bond.

  13. Molecular clusters Cs3X3 and Cs4X4 (X = Br, I: Quantum chemical study of structure and thermodynamic properties

    Stanley F. Mwanga

    2016-05-01

    Full Text Available The properties of trimer Cs3X3 and tetramer Cs4X4 (X = Br, I molecules have been studied using DFT with B3LYP5 functional and MP2 and MP4 methods. Two equilibrium geometrical structures of trimers, hexagonal (D3h and “butterfly-shaped” (Cs, and one for tetramers, distorted cubic (Td, are confirmed to exist; geometrical parameters and vibrational spectra are determined. The relative concentration of Cs3X3 isomers has been evaluated; the butterfly-shaped isomer dominates over hexagonal in saturated vapour in a broad temperature range. The dissociation reactions through different channels have been considered and enthalpies of formation ∆fH°(0 of clusters determined: ‒858 ± 20 kJ⋅mol‒1 (Cs3Br3, ‒698 ± 20 kJ⋅mol‒1 (Cs3I3, ‒1270 ± 30 kJ⋅mol‒1 (Cs4Br4 and ‒1045 ± 30 kJ⋅mol‒1 (Cs4I4. The Gibbs free energies ∆rG°(T calculated for the dissociation reactions of trimer and tetramer molecules have indicated that these molecules are resistive in narrow temperature range only and decompose spontaneously with temperature increase with elimination of dimer molecules.

  14. F-string Solution in AdS4 X CP3 PP-wave Background

    Banerjee, Gourav

    2016-01-01

    We present supergravity solution for F-string in pp wave background obtained from AdS4 X CP3 with zero flat directions.The classical solution is shown to break all space-time supersymmetries. We explicitly write down the standard as well as supernumerary Killing spinors both for the background and F-string solution.

  15. Evaluation of tests in 4x4 assemblies carried out in Columbia University

    Tests in 4x4 assemblies with BWR characteristics carried out in Columbia University are analysed, using the PANTERA-1P computer code. The experiments aim for measuring fluid, flow and enthalpies in exits of two subchannels, the coldest and hottest using iso kinetic sampling method. (M.C.K.)

  16. Submicrosecond rearrangeable nonblocking silicon-on-insulator thermo-optic 4x4 switch matrix.

    Li, Yuntao; Yu, Jinzhong; Chen, Shaowu; Li, Yanping; Chen, Yuanyuan

    2007-03-15

    A rearrangeable nonblocking silicon-on-insulator-based thermo-optic 4x4 switch matrix is designed and fabricated. A spot-size converter is integrated to reduce the insertion loss, and a new driving circuit is designed to improve the response speed. The insertion loss is less than 10 dB, and the response time is 950 ns. PMID:17308574

  17. Investigation of carbon-coated lithiated Li4+xTi5O12/C for lithium-ion batteries

    Highlights: • Lithiated Li4+xTi5O12/C with pre-stored active Li ions has been synthesized. • The first-cycle coulombic efficiency of Li4+xTi5O12/C is over 100%. • Li4+xTi5O12/C displays excellent cyclic stability and capacity retention. • TiO2 nanoparticles and carbon coating are necessary for formation of Li4+xTi5O12/C. - Abstract: Carbon-coated Li4Ti5O12 and lithiated Li4+xTi5O12 anode materials have been synthesized using nanosized anatase TiO2 and commercial TiO2 with mixed structure as Ti sources, respectively. Microstructural investigation indicates that Li4Ti5O12 and Li4+xTi5O12 are covered by amorphous carbon layers with thickness of 2–3 nm. Their electrochemical performance has been evaluated, which indicates that an amount of active Li ions have been pre-stored in the Li4+xTi5O12 lattice during solid-state synthesis, resulting in its first-cycle coulombic efficiency over 100%. Further, Li4+xTi5O12/C exhibits higher cyclic capacities than Li4Ti5O12/C at different current density. The reversible charge capacity retention of Li4+xTi5O12/C reaches 98.5% after 100 cycles, which indicates that Li4+xTi5O12/C is promising candidate anode material for long lifetime lithium-ion batteries. The formation mechanism of Li4+xTi5O12/C has been discussed, in which the nanosized anatase TiO2 with high chemical activity and the carbon coating play key roles for the formation of Li4+xTi5O12/C

  18. 8-Hydroxy-2-methylquinolinium tetrachlorido(pyridine-2-carboxylato-κ2N,Ostannate(IV

    Ezzatollah Najafi

    2011-02-01

    Full Text Available In the reaction of pyridine-2-carboxylic acid and stannic chloride in the presence of 2-methyl-8-hydroxyquinoline, the 2-methyl-8-hydroxyquinoline is protonated, yielding the title salt, (C10H10NO[SnCl4(C6H4NO2]. The SnIV atom in the anion is N,O-chelated by a pyridine-2-carboxylate in a cis-SnNOCl4 octahedral geometry. The cation is linked to the anion by an O—H...O hydrogen bond.

  19. Interplay of structural and electronic properties in itinerant AFe4X2 systems

    The AFe4X2 (A=Y,Lu,Zr; X=Ge,Si) family of transition metal tetrels has shown to be a promising candidate for studying the change of the electronic ground state under chemical substitution. Within the ZrFe4Si2-type structure (P42/mnm), the iron atoms are arranged in chains of edge-linked tetrahedral. Their structure is prone for reduced dimensionality or frustration and is thus expected to lead to emergent phenomena near a quantum critical point. Since neutron scattering data on YFe4Ge2 show a simultaneous structural and magnetic transition, electronic and structural properties seem intimately connected within the whole AFe4X2 family. On the poster, we discuss the electronic and structural properties, extracted from our μSR, Moessbauer, X-Ray and thermodynamic data in the context of a structural driven magnetic phase transition.

  20. Neutron diffraction study and magnetic properties of La2NiO4+x

    We reported the dependence of the magnetic properties of La2NiO4+x (x = 0.05 and 0.1) on the amount of the excess oxygen in the temperature range below 60 K. Weak ferromagnetic moment having spin glass like features was observed in the both compounds. La2NiO4.10 showed the shifted magnetization curve. These magnetic features were explained with the two-phase model: that is, there are two magnetic regions (the one phase is of nearly stoichiometric La2NiO4 which has the weak ferromagnetic moment, and the other is of antiferromagnetic La2NiO4+x with excess oxygen). They interact with each other in the boundary region. The neutron diffraction patterns of both specimens were refined using Rietveld analysis with two-phase model (F4/mmm+Pccn, at 15 K, and F4/mmm+Bmab, at 293 K.). (author)

  1. Scholarly Civilization: Utilizing 4X Gaming as a Framework for Humanities Digital Media

    Meeks, Elijah

    2009-01-01

    While much attention has been given to first-person shooters and puzzle games in academic scholarship, large-scale Civilization style games (known colloquially as 4X games) have received comparatively scant attention. The map-based nature of these games, with an emphasis on socio-political, socio-environmental, cultural and military activity, is particularly well-suited as a medium to express historical knowledge. However, to adapt a medium designed to entertain players to a scholarly medium ...

  2. Science Teachers' Understanding and Use of Instructional Strategies Within the 4 x 4 Block Schedule

    Grosshans, Kurt

    2006-01-01

    The primary purpose of this research was to investigate how science teachers engaged students under the 4 x 4 block schedule and how the teachersâ understanding of how they used instructional strategies influenced their lessons. As an inquiry-based approach has been adopted by the National Science Standards, research has suggested that block scheduling provides more time for teachers to incorporate varied teaching strategies such as inquiry-based teaching. This research investigated the que...

  3. Science teachers' understanding and use of instructional strategies within the 4 x 4 block schedule

    Grosshans, Kurt

    The primary purpose of this researcher was to investigate how science teachers engage students under the 4 x 4 block schedule and how the teachers' understanding of how they use instructional strategies influenced their lessons. As an inquiry-based approach has been adopted by the National Science Standards, research has suggested that block scheduling provides more time for teachers to incorporate varied strategies such as inquiry-based and cooperative learning teaching which have philosophical roots in a social constructivist philosophy. This research investigated the questions: What instructional strategies do science teachers use to engage students on the 4 x 4 block schedule? How do science teachers understand their use of instructional strategies? The methodology was qualitative in nature and involved a multiple case study of three high school science teachers at a large rural county high school. Data sources included pre-observation interviews, classroom observations, post-observation interviews, and the collection of documents and artifacts such as lesson plans, student hand-outs, worksheets, laboratory exercises, homework and other document(s) the teacher used to prepare for or implement a lesson. The evidence observed in this study, suggests that the strategies used by these three science teachers remain mostly didactic in nature. Although the teachers reported in the interview phase of this research that they use a wide variety of strategies, what was observed within the 4 x 4 block structure was the use of different didactic strategies, not different holistic strategies. Although the teachers were aware of more holistic strategies such as inquiry-based and cooperative learning, they were not adopted nor adapted within the lesson. The three teachers used strategies that were consistent with their scientific realist views concerning the nature of science. These scientific realist philosophies are antithetical to a social constructivist approach to

  4. Particle creation effect on M4 X S7 Kaluza-Klein cosmologies

    The particle creation effect on the higher-dimensional Kaluza-Klein cosmologies with M4xS7 topology is studied. This quantum effect is found to change the classical behavior of the internal and external scale factors drastically in the early stage of the expansion, so that the dimensional reduction seems to fail. However, at the later stage two scale factors get separated from each other and the internal scale factor approaches the final singularity just like the vacuum case. (orig.)

  5. Electronic and optical properties of CoX2O4 (X = Al, Ga, In) alloys

    Feng, Chunbao; Yin, Wan-Jian; Nie, Jinlan; Zu, Xiaotao; Huda, Muhammad N.; Wei, Su-Huai; Al-Jassim, Mowafak M.; Turner, John A.; Yan, Yanfa

    2012-01-01

    The electronic and optical properties of Co based spinel oxides, CoX2O4 (X = Al, Ga, In) are calculated using first-principle density functional theory. We show that the desirable properties for solar photoconversion can be obtained by controlling the alloy compositions. The ability to manipulate the electronic and optical properties is attributed to the different s-orbital energies and sizes of the cations. Our calculated bandgaps as function of composition provide detailed practical guidance for synthesizing Co based spinel oxides with electronic and optical properties necessary to achieve high efficiency photoelectrochemical decomposition of water for hydrogen production by sunlight.

  6. Optical 4x4 hitless slicon router for optical networks-on-chip (NoC).

    Sherwood-Droz, Nicolás; Wang, Howard; Chen, Long; Lee, Benjamin G; Biberman, Aleksandr; Bergman, Keren; Lipson, Michal

    2008-09-29

    We demonstrate here a spatially non-blocking optical 4x4 router with a footprint of 0.07 mm(2) for use in future integrated photonic interconnection networks. The device is dynamically switched using thermo-optically tuned silicon microring resonators with a wavelength shift to power ratio of 0.25nm/mW. The design can route four optical inputs to four outputs with individual bandwidths of up to 38.5 GHz. All tested configurations successfully routed a single-wavelength laser and provided a maximum extinction ratio larger than 20 dB. PMID:18825228

  7. Arctic sea ice and atmospheric circulation under the abrupt4xCO2 scenario

    YU Xiaoyong; Annette Rinke; JI Duoying; CUI Xuefeng; John C Moore

    2014-01-01

    We analyze sea ice changes from eight different earth system models that have conducted experiment abrupt4xCO2 of the Coupled Model Intercomparison Project Phase 5 (CMIP5). In response to abrupt quadrupling of CO2 from preindustrial levels, Arctic temperatures dramatically rise by about 10°C—16°C in winter and the seasonal sea ice cycle and sea ice concentration are signiifcantly changed compared with the pre-industrial control simulations (piControl). Changes of Arctic sea ice concentration are spatially correlated with temperature patterns in all seasons and highest in autumn. Changes in sea ice are associated with changes in atmospheric circulation patterns at heights up to the jet stream. While the pattern of sea level pressure changes is generally similar to the surface air temperature change pattern, the wintertime 500 hPa circulation displays a positive Paciifc North America (PNA) anomaly under abrupt4xCO2-piControl. This large scale teleconnection may contribute to, or feedback on, the simulated sea ice cover change and is associated with an intensiifcation of the jet stream over East Asia and the north Paciifc in winter.

  8. Crystal structure of LuCu4-xSb2 (x = 1.053)

    Crystal structure of new ternary antimonide LuCu4-xSb2 (x = 1.053(8)) was refined by means of powder diffraction method (diffractometer DRON-3M, Cu Kα-radiation, RB = 4.09, χ2 = 1.92). It crystallizes in orthorhombic type of structure ErFe4Ge2 (low-temperature modification): space group Pnnm, Pearson code oP14-2.11, a = 7.01189(14), b = 7.75061(15), c = 4.24323(8) A; Z = 2. Analysing the coordination environments of atoms it was shown, that investigated structure is an inclusion derivative of TiO2 structure type. TiO2, NiAs, MnBi, Ag2HgS2, Ni2In and RCu4-xSb2 (R Tm, Lu) structures belongs to the family of structures built up from the columns of filled octahedra and differ by the filling of space between them by different atoms or groups of atoms

  9. Interaction region of 4 x 7-GeV asymmetric B-factory

    In this paper the authors formulate the solution to the central question of the 4 x 7-GeV asymmetric B-factory design the question of the interaction region arrangement. The fact is that for this beam energy difference (not very small and at the same time not very large) the possibility of the solution of this problem without losing luminosity compared to the symmetric case was not clear. At the same time, the asymmetry of 4 x 7 GeV is very attractive due to some important reasons. Beginning approximately from this asymmetry all physical advantages of observation of the decays of moving B-mesons are already realized and one can consider this as a low limitation on the beam energy difference. On the other hand, one is faced with the following dilemma as the asymmetry increases. If the energy difference is not yet very large, it is difficult, if possible at all, to focus both beams at the interaction point (IP). When the energy difference is large, this problem disappears, but is replaced by another the high cost of such a machine

  10. NMR and NQR studies on UCu4+xAl8-x (0 < x < 2) system

    We have studied the microscopic properties of the ThMn12-type UCu4+xAl8-x (0 27Al NMR and 63,65Cu NQR. With increasing x from x = 0, the Neel temperature TN decreased and disappeared abruptly at xc = 1.15. No magnetic ordering was detected down to 1.3 K for x ≥ xc by the NMR, suggesting that the effect of short-range magnetic ordering is not a major origin of the heavy-fermion-like (i.e. large C/T) behavior observed for x ≥ xc. From the K versus χ plot in UCu4+xAl8-x, the transferred hyperfine field Hhf for Al was determined to be 0.80, 0.77, 0.45 and 1.1 kOe/μB-Ce for x = 0.25, 0.50, 1.10 and 1.50, respectively. By NQR measurements at 1.3-4.2 K for x = 0.25 no resultant hyperfine field was observed at Cu sites in the AF ordered state, indicating a cancellation of Hhf at the 8(f) Cu sites in the type I AF. The relaxation rate 1/T1 by 63Cu NQR for x 1.5 at 1.3-4.2 K revealed the Korringa-like behavior. (orig.)

  11. POWER, HEART RATE AND PERCEIVED EXERTION RESPONSES TO 3X3 AND 4X4 BASKETBALL SMALL-SIDED GAMES

    Jaime Sampaio

    2009-01-01

    significant increase in the countermovement jump posttest jump results could suggest that the 4x4 were not played as quickly nor intensely as the 3x3. Decreases of the space and number of players in game allow greater self-recreation of players and greater intervention in game. Therefore, the heart rate response during the series displays a higher physiologic impact in 3x3 than in 4x4.

  12. Two Component Dark Matters in S_4 x Z_2 Flavor Symmetric Extra U(1) Model

    Daikoku, Yasuhiro; Toma, Takashi

    2011-01-01

    We study cosmic-ray anomaly observed by PAMELA based on E_6 inspired extra U(1) model with S_4 x Z_2 flavor symmetry. In our model, the lightest flavon has very long lifetime of O(10^{18)) second which is longer than the age of the universe, but not long enough to explain the PAMELA result ~ O(10^{26}) sec. Such a situation could be avoidable by considering that the flavon is not the dominant component of dark matters and the dominant one is the lightest neutralino. With appropriate parameter set, density parameter of dark matter and over-abundance of positron flux in cosmic-ray are realized at the same time. There is interesting correlation between spectrum of positron flux and V_{MNS}. No excess of anti-proton in cosmic-ray suggests that sfermions are heavier than 4 TeV and the masses of the light Higgs bosons are degenerated.

  13. A SUSY GUT of Flavour with S4 x SU(5) to NLO

    Hagedorn, Claudia; Luhn, Christoph

    2010-01-01

    We construct a realistic Supersymmetric (SUSY) Grand Unified Theory (GUT) of Flavour based on S4 x SU(5), together with an additional (global or local) Abelian symmetry, and study it to next-to-leading order (NLO) accuracy. The model includes a successful description of quark and lepton masses and mixing angles at leading order (LO) incorporating the Gatto-Sartori-Tonin (GST) relation and the Georgi-Jarlskog (GJ) relations. We study the vacuum alignment arising from F-terms to NLO and such corrections are shown to have a negligible effect on the results for fermion masses and mixings achieved at LO. Tri-bimaximal (TB) mixing in the neutrino sector is predicted very accurately up to NLO corrections of order 0.1%. Including charged lepton mixing corrections implies small deviations from TB mixing described by a precise sum rule, accurately maximal atmospheric mixing and a reactor mixing angle close to three degrees.

  14. Microscopic phase separation in La2CuO4+x induced by the superconducting transition

    The phase separation (PS) effect in superconducting La2CuO4+x (x ≤ 0.04) single crystals with low oxygen mobility was studied via μSR spectroscopy, high resolution neutron diffraction and magnetic susceptibility. Despite the fact that all crystals are inside the miscibility gap (0.01 < x < 0.06), only crystals with a sufficiently large excess oxygen concentration x ≥ 0.04 show a macroscopic phase separation according to the neutron diffraction data. However, in all samples a phase transition to an ordered magnetic state was observed by μSR spectroscopy concomitantly with the onset of superconductivity. This unexpected behaviour suggests that the underlying microscopic PS is driven by superconductivity

  15. Quad fourfold (4 X 4) logic unit (LBL No. 21X6421 P-1)

    A quad fourfold (4 x 4) logic unit has been designed and packaged in a single-width NIM module for use in nuclear and atomic physics experiments. The four inputs of each unit are combined internally to perform logical AND, OR, and VETO functions. A set of eight DIP switches on the front panel select either the input signal or its complement, trigger slope, output pulse duration, and positive or negative logic on the overlap signal. A one-shot multivibrator may be triggered on either the positive or negative-going slope of the overlap signal to form the shaped output. The output width can be adjusted between ∼50 ns and 50 μsec with two coarse ranges and a twenty-turn potentiometer. An LED attached to the one-shot gives a visual indication of the output rate. 4 figs

  16. Magnetic, electrical and thermodynamic properties of the UCu4-xCrxAl8 system

    The UCu4-xCrxAl8 system exists in the whole concentration range and crystallizes in the tetragonal ThMn12-type structure. The elemental cell volume increases with increasing x. The magnetic susceptibility, χ, of the alloys follows a modified Curie-Weiss law above ∼50 K. At low temperature, χ(T) of all the pseudoternaries does not exhibit any anomaly which could indicate magnetic ordering. The temperature dependence of electrical resistivity, ρ, for alloys with x=1 and 2 show anomalies at temperatures fairly close to TN (∼30 K) of UCu4Al8. Above the anomalies which have a form of maxima, the ρ(T) plots decrease with the temperature up to room temperature. Specific heat of UCu3CrAl8 extrapolated from high temperature region gives γ=100 mJ/molK2 and θD = 165 K. (author)

  17. Spontaneous CP violation in A4xSU(5) with Constrained Sequential Dominance 2

    Antusch, Stefan; Spinrath, Martin

    2013-01-01

    We revisit a two right-handed neutrino model with two texture zeros, namely an indirect model based on A4 with the recently proposed new type of constrained sequential dominance (CSD2), involving vacuum alignments along the (0,1,-1)^T and (1,0,2)^T directions in flavour space, which are proportional to the neutrino Dirac mass matrix columns. In this paper we construct a renormalizable and unified indirect A4xSU(5) model along these lines and show that, with spontaneous CP violation and a suitable vacuum alignment of the phases, the charged lepton corrections lead to a reactor angle in good agreement with results from Daya Bay and RENO. The model predicts a right-angled unitarity triangle in the quark sector and a Dirac CP violating oscillation phase in the lepton sector of delta approximately 130 degrees, while providing a good fit to all quark and lepton masses and mixing angles.

  18. SU(4) x U(1) gauge theory. III. New approach to Cabibbo mixing

    A new approach to Cabibbo mixing is proposed in the framework of an SU(4) x U(1) gauge theory. Instead of introducing Cabibbo mixing in the quark mass matrix as is usually done in SU(2) x U(1), we take advantage of the existence of the 12 additional gauge bosons and mix the gauge bosons in their mass matrix. It is found that in the most general case there are four mixing angles which are in principle observable. Among them one is the usual Cabibbo angle; another one is like it but is in a different sector. Two angles are associated with CP nonconservation. By demanding that the Higgs potential have the most general form, we show that in our theory Cabibbo mixing and CP and muon-number nonconservation are inevitable. An intimate connection between the Cabibbo angle and the muon-number-nonconserving μ → eγ process is obtained. Possible experimental tests of our theory are suggested

  19. Magnetoresistance measurements in UCu4+xAl8-x compounds

    The intermetallic UCu4+xAl8-xcompounds (0.1≤x≤1.95) have remarkable electronic and magnetic properties. The Cu-poor compositions within this x-range are antiferromagnetic (AF). The Neel temperature (TN) drops gradually from ∼36 K for x=0.1 until AF is completely suppressed near x=1.1, while the Sommerfeld coefficient (γ) increases dramatically with x, reaching a maximum value of 750 mJ/mol K2 for x=1.75. Reported in this investigation are magnetoresistance (MR) and magnetic susceptibility (χ) measurements at low temperatures (T) and high magnetic fields (B). The isothermal MR data below 40 K crosses over from positive in the low-x to negative in the high-x range. These results are interpreted in the context of spin fluctuations, hybridization, and non-magnetic atomic disorder

  20. Specific Heat of the UCu4+xAl8-x Derivatives

    The low temperature (T4+xAl8-x derivatives in which the 3d elements (Cr, Mn and Ni) have been substituted for Cu, and Ga for Al is presented. The parent alloys have exhibited an alloying induced transition from simple antiferromagnetic ordering for low Cu--concentration (for x ≤ 1.25) to heavy-fermion-like properties (for x ≥ 1.5). The crystallographic disorder introduced by a change of stoichiometry could be the reason for enhanced γ. These components slightly change both the crystallographic relations and electronic structure, and the determined thermodynamic data strongly suggest other reasons for an enhanced γ than crystallographic disorder. The occurrence of the T3 ln T term in specific heat for all alloys except that of Ni provides the conclusion about spin fluctuation state. The Ni compound is antiferromagnetic below TN=27.5 K. (author)

  1. 40-GHz operation of a single-flux-quantum (SFQ) 4 x 4 switch scheduler

    We designed a single-flux-quantum (SFQ) scheduler for a 4 x 4 network switch. It receives requests serially and arbitrates them. Fair scheduling is achieved by using a round-robin priority pointer at each output port. The pointer is updated so that the input port that was granted permission has the lowest priority in the next scheduling cycle. We divided the scheduler into sub-blocks, which were separately designed. The sub-blocks, which have asynchronous interfaces, were then connected with passive transmission lines. Ladder-type on-chip clock generators were included in the circuit for high-speed operation. Using logic simulation, we verified the scheduler test circuit. The scheduler test circuit was composed of about 3000 Josephson junctions. We tested the scheduler circuit at high speed and confirmed correct operations at over 40 GHz

  2. Phenomenological Implications of an S4 x SU(5) SUSY GUT of Flavour

    Dimou, Maria; Luhn, Christoph

    2015-01-01

    We discuss the low energy phenomenological implications of an SU(5) Supersymmetric Grand Unified Theory (SUSY GUT) whose flavour structure is controlled by the family symmetry S4 x U(1), which provides a good description of all quark and lepton masses, mixings as well as CP violation. Although the model closely mimics Minimal Flavour Violation (MFV) as shown in arXiv:1511.07886, here we focus on the differences. We first present numerical estimates of the low energy mass insertion parameters, including canonical normalisation and renormalisation group running, for well-defined ranges of SUSY parameters and compare the naive model expectations to the numerical scans and the experimental bounds. Our results are then used to estimate the predictions for Electric Dipole Moments (EDMs), Lepton Flavour Violation (LFV), B and K meson mixing as well as rare B decays. The largest observable deviations from MFV come from the LFV process mu --> e gamma and the EDMs.

  3. Structural and Magnetothermal Properties of Compounds: Yb5SixGe4-x,Sm5SixGe4-x, EuO, and Eu3O4

    Kyunghan Ahn

    2007-05-09

    The family of R{sub 5}Si{sub x}Ge{sub 4-x} alloys demonstrates a variety of unique physical phenomena related to magneto-structural transitions associated with reversible breaking and reforming of specific bonds that can be controlled by numerous external parameters such as chemical composition, magnetic field, temperature, and pressure. Therefore, R{sub 5}Si{sub x}Ge{sub 4-x} systems have been extensively studied to uncover the mechanism of the extraordinary magneto-responsive properties including the giant magnetoresistance (GMR) and colossal magnetostriction, as well as giant magnetocaloric effect (GMCE). Until now, more than a half of possible R{sub 5}Si{sub x}Ge{sub 4-x} pseudobinary systems have been completely or partially investigated with respect to their crystallography and phase relationships (R = La, Pr, Nd, Gd, Tb, Dy, Er, Lu, Y). Still, there are other R{sub 5}Si{sub x}Ge{sub 4-x} systems (R = Ce, Sm, Ho, Tm, and Yb) that are not studied yet. Here, we report on phase relationships and structural, magnetic, and thermodynamic properties in the Yb{sub 5}Si{sub x}Ge{sub 4-x} and Sm{sub 5}Si{sub x}Ge{sub 4-x} pseudobinary systems, which may exhibit mixed valence states. The crystallography, phase relationships, and physical properties of Yb{sub 5}Si{sub x}Ge{sub 4-x} alloys with 0 {le} x {le} 4 have been examined by using single crystal and powder x-ray diffraction at room temperature, and dc magnetization and heat capacity measurements between 1.8 K and 400 K in magnetic fields ranging from 0 to 7 T. Unlike the majority of R{sub 5}Si{sub x}Ge{sub 4-x} systems studied to date, where R is the rare earth metal, all Yb-based germanide-silicides with the 5:4 stoichiometry crystallize in the same Gd{sub 5}Si{sub 4}-type structure. The magnetic properties of Yb{sub 5}Si{sub x}Ge{sub 4-x} materials are nearly composition-independent, reflecting the persistence of the same crystal structure over the whole range of x from 0 to 4. Both the crystallographic and

  4. Specific heat of the UCu4+xAl8-x derivatives

    The discovery of heavy fermion - like behavior in UCu4+xAl8-x ternaries [1,2 J has aroused interest in the properties of their derivatives. The investigation of parent alloys has shown an alloying induced transition from simple antiferromagnetic ordering for low Cu - concentration (x 1.5) [2]. Recently, Nishioka et al. [3] have presented a phase diagram of this system and have established that there probably exist three states : antiferromagnetic (AF), heavy - fermion (HF) and non-Fermi liquid (nFL) ones depending on x. As the most pronounced indication of the HF state, enhanced coefficient of the electronic specific heat (y) is suggested. These alloys exhibit the tetragonal ThMn12 type structure (I4/mmm space group) with four nonequivalent crystallographic sites : 2a occupied by uranium atoms, and 8f 8i and 8j positions in which the Cu and A1. atoms are located. Such a structure can produce a crystallographic disorder which in turn can be a reason for the high value of y. To explain this problem, we have started the research on the derivatives of UCu4+xAl8-x alloys in which Fe [4J, Ni [5], Mn [6] and Cr [7] being substituted for Cu and Ga for A1 [8], have been examined. These components slightly change both crystallochemical relations (the U - U separation and possibly the crystallographic sites occupation) and electronic structure. The magnetic and electrical properties of these systems investigated so far now did not provide any clear-cut indication of the influence of these added components on the behavior of pseudo ternaries

  5. Thermoelectric transport in the layered Ca3Co4-xRhxO9 single crystals

    Ikeda, Yusuke; Saito, Kengo; Okazaki, Ryuji

    2016-06-01

    We have examined an isovalent Rh substitution effect on the transport properties of the thermoelectric oxide Ca3Co4O9 using single-crystalline form. With increasing Rh content x, both the electrical resistivity and the Seebeck coefficient change systematically up to x = 0.6 for Ca3Co4-xRhxO9 samples. In the Fermi-liquid regime where the resistivity behaves as ρ = ρ 0 + A T 2 around 120 K, the A value decreases with increasing Rh content, indicating that the correlation effect is weakened by Rh 4d electrons with extended orbitals. We find that, in contrast to such a weak correlation effect observed in the resistivity of Rh-substituted samples, the low-temperature Seebeck coefficient is increased with increasing Rh content, which is explained with a possible enhancement of a pseudogap associated with the short-range order of spin density wave. In high-temperature range above room temperature, we show that the resistivity is largely suppressed by Rh substitution while the Seebeck coefficient becomes almost temperature-independent, leading to a significant improvement of the power factor in Rh-substituted samples. This result is also discussed in terms of the differences in the orbital size and the associated spin state between Co 3d and Rh 4d electrons.

  6. Photoelectric properties of defect chalcogenide HgGa2X4 (x=S, Se, Te)

    Sharma, Ramesh; Dwivedi, Shalini; Sharma, Yamini

    2016-05-01

    We present results of ab initio study of ordered vacancy compounds of mercury. The electronic structure, charge density, optical and transport properties of the semiconductor family HgGa2X4 (X=S, Se, Te) are calculated using the full potential linearized augmented plane wave method which is based on the density functional theory. A direct bandgap is observed in these compounds, which reduces in the order S>Se>Te. From the density of states it is observed that there is strong hybridization of Hg-d, Ga-d and X-p states. The optical properties show a red shift with increasing size and atomic no. of the chalcogenide atoms. We have also reported the transport properties of mercury thiogallates for the first time. The selenide compound exhibits n-type nature whereas HgGa2S4 and HgGa2Te4 show p-type behavior. The power factor and ZT for the HGS increases at low temperatures, the figure of merit is highest for HgGa2Se4 (1.17) at 19 K.

  7. An SO(10)xS4xZn model of Quark-Lepton Complementarity

    The present observations of Cabibbo angle and solar mixing angle satisfy the empirical relation called Quark-Lepton Complementarity (QLC), namely θ12l∼π/4-θC. It suggests the existence of correlation between quarks and leptons which is supported by the idea of grand unification. We propose a specific ansatz for the structure of Yukawa matrices in SO(10) unified theory which leads to similar relation if neutrinos get masses through type-II seesaw mechanism. Viability of this ansatz is discussed through detailed analysis of fermion masses and mixing angles all of which can be explained in a model which uses three Higgs fields transforming as 10 and one transforming as 126-bar representations under SO(10). It is shown that the proposed ansatz can be derived from an extended model based on the two pairs of 16-dimensional vector-like fermions and an S4xZn flavor symmetry. The model leads to the lepton mixing matrix that is dominantly bimaximal with O(θC) corrections related to quark mixings. A generic prediction of the model is the reactor angle θ13l∼θC/√(2) which is close to its present experimental upper bound.

  8. Short-range order parameters in amorphous YBaS4X7(X-S, SE, TE) films

    Full text : Electron scattering intensity curves from amorphous YbAs4X7(X-S, SE, TE) films have ben obtained by the transmission electron diffraction (TED) method with rotation sector before screen up. The energy of electrons was 100 keV. Amorphous samples were crystallized and the composition of the products were measured by TED. The atomic radial distribution function has been calculated by the Fourier synthesis of intensities in the TED of amorphous YbAs4X7(X-S, SE, TE) films. The interatomic average distances of As - S (Se, Te) and As-Yb+2 and partial coordination numbers have been estimated in these thilms. Based on these numbers, chemical orders in these films differ. This difference is due to differing topological order in the amorphous YbAs4X7(X-S, SE, TE) films

  9. Scanning tunneling microscopy study of the c(4x4) structure formation in the sub-monolayer Sb/Si(100) system

    Upon Sb desorption from a Sb-saturated Si(100) surface, the c(4x4) structure formed at about 0.25 monolayer Sb coverage. The c(4x4) reconstruction has been found to develop best when the surface is slightly contaminated, plausibly, by carbon. The Si(100)-c(4x4)-Sb surface shows up in the high-resolution filled state scanning tunneling microscopy images as being very similar to that of the recently reported c(4x4)-Si reconstruction. Here the main features of the Si(100)-c(4x4)-Sb structure are identified and the possible atomic arrangement is discussed. (author)

  10. Emission Spectroscopy of the 4X Source Discharge With and Without N2 Gas

    Smith, Horace Vernon [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-01-14

    This tech note summarizes the December, 1988 emission spectroscopy measurements made on the 4X source discharge with and without N₂ gas added to the H + Cs discharge. This study is motivated by the desire to understand why small amounts of N₂ gas added to the source discharge results in a reduction in the H⁻ beam noise. The beneficial effect of N₂ gas on H⁻ beam noise was first discovered by Bill Ingalls and Stu Orbesen on the ATS SAS source. For the 4X source the observed effect is that when N2 gas is added to the discharge the H⁻ beam noise is reduced about a factor of 2.

  11. Observation of the suppression of the flux of cosmic rays above 4x10^19eV

    Abraham, J; Aglietta, M; Aguirre, C; Allard, D; Allekotte, I; Allen, J; Allison, P; Alvarez-Muñiz, J; Ambrosio, M; Anchordoqui, L; Andringa, S; Anzalone, A; Aramo, C; Argiro, S; Arisaka, K; Armengaud, E; Arneodo, `F; Arqueros, F; Asch, T; Asorey, H; Assis, P; Atulugama, B S; Aublin, J; Ave, M; Avila, G; Backer, T; Badagnani, D; Barbosa-Ademarlaudo, F; Barnhill, D; Barroso, S L C; Baughman, B; Bauleo, P; Beatty, J J; Beau, T; Becker, B R; Becker, K H; Bellido, J A; Ben Zvi, S; Bérat, C; Bergmann, T; Bernardini, P; Bertou, X; Biermann, P L; Billoir, P; Blanch-Bigas, O; Blanco, F; Blasi, P; Bleve, C; Blümer, H; Bohacova, M; Bonifazi, C; Bonino, R; Brack, J; Brogueira, P; Brown, W C; Buchholz, P; Bueno, A; Burton, R E; Busca, N G; Caballero-Mora, K S; Cai, B; Camin, D V; Caramete, L; Caruso, R; Carvalho, W; Castellina, A; Catalano, O; Cataldi, G; Cazon, L; Cester, R; Chauvin, J; Chiavassa, A; Chinellato, J A; Chou, A; Chudoba, J; Chye, J; Clark, P D J; Clay, R W; Colombo, E; Conceicao, R; Connolly, B; Contreras, F; Coppens, J; Cordier, A; Cotti, U; Coutu, S; Covault, C E; Creusot, A; Criss, A; Cronin, J; Curutiu, A; Dagoret-Campagne, S; Daumiller, K; Dawson, B R; de Almeida, R M; De Donato, C; De Jong, S J; De La Vega, G; de Mello Junior, W J M; De Mello-Neto, J R T; De Mitri, I; De Souza, V; Del Peral, L; Deligny, O; Della Selva, A; Delle Fratte, C; Dembinski, H; Di Giulio, C; Diaz, J C; Diep, P N; Dobrigkeit, C; D'Olivo, J C; Dong, P N; Dornic, D; Dorofeev, A; dos Anjos, J C; Dova, M T; D'Urso, D; Dutan, I; Duvernois, M A; Engel, R; Epele, L; Erdmann, M; Escobar, C O; Etchegoyen, A; Facal San Luis, P; Falcke, H; Farrar, G; Fauth, A C; Fazzini, N; Ferrer, F; Ferrero, A; Fick, B; Filevich, A; Filipcic, A; Fleck, I; Fracchiolla, C E; Fulgione, W; Garca, B; Garca Gamez, D; Garcia-Pinto, D; Garrido, X; Geenen, H; Gelmini, G; Gemmeke, H; Ghia, P L; Giller, M; Glass, i H; Gold, M S; Golup, G; Gomez Albarracin, F; Gomez Berisso, M; Gonçalves, P; Goncalvesdo Amaral, M; González, D; Gonzalez, J G; González, M; Gora, D; Gorgi, A; Gouffon, P; Grassi, V; Grillo, A F; Grunfeld, C; Guardincerri, Y; Guarino, F; Guedes, G P; Gutíerrez, J; Hague, J D; Halenka, V; Hamilton, J C; Hansen, P; Harari, D; Harmsma, S; Harton, J L; Haungs, A; Hauschildt, T; Healy, M D; Hebbeker, T; Hebrero, G; Heck, D; Hojvat, C; Holmes, V C; Homola, P; Hörandel, J R; Horneffer, A; Hrabovsky, M; Huege, T; Hussain, M; Iarlori, M; Insolia, A; Ionita, F; Italiano, A; Kaducak, M; Kampert, K H; Karova, T; Kasper, P; Kegl, B; Keilhauer, B; Kemp, E; Kieckhafer, R M; Klages, H O; Kleifges, M; Kleinfeller, J; Knapik, R; Knapp, J; Koang, D H; Krieger, A; Krömer, O; Kuempel, D; Kunka, N; Kusenko, A; La Rosa, G; Lachaud, C; Lago, B L; Lebrun, D; Lebrun, P; Lee, J; Leiguide Oliveira, M A; Letessier-Selvon, A A; Leuthold, M; Lhenry-Yvon, I; López, R; López-Aguera, A; Lozano-Bahilo, J; Lucero, A; Luna Garca, R; Maccarone, i M C; Macolino, C; Maldera, S; Mancarella, G; Mancenido, M E; Mandat, D; Mantsch, P; Mariazzi, A G; Maris, I C; Marquez Falcon, H R; Martello, D; Martínez, J; Martinez Bravo, O; Mathes, H J; Matthews, J; Matthews, J A J; Matthiae, Giorgio; Maurizio, D; Mazur, P O; McCauley, T; McEwen, M; McNeil, R R; Medina, M C; Medina-Tanco, G; Melo, D; Menichetti, E; Menschikov, A; Meurer, C; Meyhandan, R; Micheletti, M I; Miele, G; Miller, W; Mollerach, S; Monasor, M; Monnier Ragaigne, D; Montanet, F; Morales, B; Morello, C; Moreno, J C; Morris, C; Mostafa, M; Muller, M A; Mussa, R; Navarra, G; Navarro, J L; Navas, S; Necesal, P; Nellen, L; Newman-Holmes, C; Newton, D; Nhung, P T; Nierstenhoefer, N; Nitz, D; Nosek, D; Nozka, L; Oehlschläger, J; Ohnuki, T; Olinto, A; Olmos-Gilbaja, V M; Ortiz, M; Ortolani, F; Ostapchenko, S; Otero, L; Pacheco, N; Pakk Selmi-Dei, D; Palatka, M; Pallotta, J; Parente, G; Parizot, E; Parlati, S; Pastor, S; Patel, M; Paul, T; Pavlidou, V; Payet, K; Pech, M; Pekala, J; Pelayo, R; Pepe, I M; Perrone, L; Pesce, R; Petrera, S; Petrinca, P; Petrov, Y; Pichel, A; Piegaia, R; Pierog, T; Pimenta, M; Pinto, T; Pirronello, V; Pisanti, O; Platino, M; Pochon, J; Privitera, P; Prouza, M; Quel, E J; Rautenberg, J; Redondo, A; Reucroft, S; Revenu, B; Rezende, F A S; Rídky, J; Riggi, S; Risse, M; Rivière, C; Rizi, V; Roberts, M; Robledo, C; Rodríguez, G; Rodríguez-Martino, J; Rodriguez Rojo, J; Rodriguez-Cabo, I; Rodrguez-Fras, M D; Ros, G; Rosado, J; Roth, M; Rouille-d'Orfeuil, B; Roulet, E; Rovero, A C; Salamida, F; Salazar, ii H; Salina, G; Sánchez, F; Santander, M; Santo, C E; Santos, E M; Sarazin, F; Sarkar, S; Sato, R; Scherini, V; Schieler, H; Schmidt, A; Schmidt, F; Schmidt, T; Scholten, O; Schovanek, P; Schroeder, F; Schulte, S; Schussler, F; Sciutto, S J; Scuderi, M; Segreto, A; Semikoz, D; Settimo, M; Shellard, R C; Sidelnik, I; Siffert, B B; Sigl, G; Smetniansky De Grande, N; Smialkowski, A; Smda, R; Smith, A G K; Smith, B E; Snow, G R; Sokolsky, P; Sommers, P; Sorokin, J; Spinka, H; Squartini, R; Strazzeri, E; Stutz, A; Suárez, F; Suomijärvi, T; Supanitsky, A D; Sutherland, M S; Swain, J; Szadkowski, Z; Takahashi, J; Tamashiro, A; Tamburro, A; Tarutina, T; Tascau, O; Tcaciuc, R; Thao, N T; Thomas, D; Ticona, R; Tiffenberg, J; Timmermans, C; Tkaczyk, W; Todero Peixoto, C J; Tomé, B; Tonachini, A; Torres, I; Travnicek, P; Tripathi, A; Tristram, G; Tscherniakhovski, D; Tuci, V; Tueros, M; Tunnicliffe, V; Ulrich, R; Unger, M; Urban, M; Valdés-Galicia, J F; Valino, I; Valore, L; vanden Berg, A M; van Elewyck, V; Vázquez, R A; Veberic, D; Veiga, A; Velarde, A; Venters, T; Verzi, V; Videla, M; Villaseñor, L; Vorobiov, S; Voyvodic, L; Wahlberg, H; Wahrlich, P; Wainberg, O; Walker, P; Warner, D; Watson, A A; Westerhoff, S; Wieczorek, G; Wiencke, L; Wilczynska, B; Wilczynski, H; Wileman, C; Winnick, M G; Wu, H; Wundheiler, B; Yamamoto, T; Younk, P; Zas, E; Zavrtanik, D; Zavrtanik, M; Zaw, I; Zepeda, A; Ziolkowski, M

    2008-01-01

    The energy spectrum of cosmic rays above 2.5x10^18eV, derived from 20,000 events recorded at the Pierre Auger Observatory, is described. The spectral index gamma of the flux, J ~ E^-gamma, at energies between 4x10^18eV and 4x10^19eV is 2.69+-0.02(stat)+-0.06(syst), steepening to 4.2+-0.4(stat)+-0.06(syst) at higher energies, consistent with the prediction by Greisen and by Zatsepin and Kuz'min.

  12. Electronic properties and structural properties of Li (1 - chi) FePO 4 (X = 0 , 0.5 ,1)

    Kinyanjui, Michael Kiarie

    2010-01-01

    Lithium iron phosphate (LiFePO4) is currently applied as a cathode material for lithium ion batteries. However, its electronic properties and the mechanism by which lithium ions are extracted (delithiation) or inserted (lithiation) into the lattice are still not completely understood. In this thesis the electronic and structural properties of Li(1-x)FePO4 (LiFePO4 x = 0, FePO4 x = 1) have been investigated using valence and core loss electron energy loss spectroscopy (EELS) and high resolutio...

  13. D = 3 N=6 superconformal symmetry of the AdS4xCP3 superstring

    Invariance of the AdS4xCP3 superstring under D = 3 N=6 superconformal symmetry is discussed in the sector described by the OSp(4|6)/(SO(1, 3) x U(3)) supercoset sigma-model action presented in the conformal basis for the osp(4|6)/(so(1, 3) x u(3)) Cartan forms. Transformation rules under D = 3 N=6 superconformal symmetry for the (10|24)-dimensional 'reduced' AdS4xCP3 superspace coordinates are obtained and used to derive corresponding world-sheet currents. (paper)

  14. Implementation of a 4x8 NIR and CCD Mosaic Focal Plane Technology

    Jelinsky, Patrick; Bebek, C. J.; Besuner, R. W.; Haller, G. M.; Harris, S. E.; Hart, P. A.; Heetderks, H. D.; Levi, M. E.; Maldonado, S. E.; Roe, N. A.; Roodman, A. J.; Sapozhnikov, L.

    2011-01-01

    Mission concepts for NASA's Wide Field Infrared Survey Telescope (WFIRST), ESA's EUCLID mission, as well as for ground based observations, have requirements for large mosaic focal planes to image visible and near infrared (NIR) wavelengths. We have developed detectors, readout electronics and focal plane design techniques that can be used to create very large scalable focal plane mosaic cameras. In our technology, CCDs and HgCdTe detectors can be intermingled on a single, silicon carbide (SiC) cold plate. This enables optimized, wideband observing strategies. The CCDs, developed at Lawrence Berkeley National Laboratory, are fully-depleted, p-channel devices that are backside illuminated capable of operating at temperatures as low as 110K and have been optimized for the weak lensing dark energy technique. The NIR detectors are 1.7µm and 2.0µm wavelength cutoff H2RG® HgCdTe, manufactured by Teledyne Imaging Sensors under contract to LBL. Both the CCDs and NIR detectors are packaged on 4-side abuttable SiC pedestals with a common mounting footprint supporting a 44.16mm mosaic pitch and are coplanar. Both types of detectors have direct-attached, readout electronics that convert the detector signal directly to serial, digital data streams and allow a flexible, low cost data acquisition strategy, despite the large data volume. A mosaic of these detectors can be operated at a common temperature that achieves the required dark current and read noise performance in both types of detectors necessary for dark energy observations. We report here the design and integration for a focal plane designed to accommodate a 4x8 heterogeneous array of CCDs and HgCdTe detectors. Our current implementation contains over 1/4-billion pixels.

  15. Electron transfer U3+-U4+ in UCu4+xAl8-x, initiated by composition

    Electron structure of uranium in UCu4+xAl8-x and its dependence on composition and phase transformations are investigated. It is shown that with copper atom substitution for aluminium ones, the population of 5f-shell of uranium is decreased, that is, 5f-electron transfer to s- or d-zone of conductivity takes place

  16. Synthesis of monohydrates of double lithium molybdates and tungstates with rubidium and potassium M+LiEO4xH2O and crystal structure of RbLiMoO4xH2O

    Monocrystals of M+LiEO4xH2O , where M=Rb, K, E=Mo, W prepared by evaporation of aqueous solution are isostructural with respect to X-ray diffraction characteristics and crystallize in orthorhombic syngony. Crystal structure of RbLiMoO4xH2O was specified up to R=0.066 (sp. gr. Dsub(2h)sup(15)=Psub(cab), a=7.870 (3), b=10 725 (6), c=13.015 (6),Z=8). The layers of double-level crimped lattices composed of alternating Mo- and Li-tetrahedrons with average Mo-O and Li-O distances equal to 1.755 and 1.95 A respectively are distinguished in the structure. The layers are connected by Rb-cations and hydrogen bonds. Lattice parameters of other compounds were calculated according to the data of powder diffractograms

  17. Observation of the suppression of the flux of cosmic rays above 4 x 10 (19) eV.

    Abraham, J; Abreu, P; Aglietta, M; Aguirre, C; Allard, D; Allekotte, I; Allen, J; Allison, P; Alvarez-Muñiz, J; Ambrosio, M; Anchordoqui, L; Andringa, S; Anzalone, A; Aramo, C; Argirò, S; Arisaka, K; Armengaud, E; Arneodo, F; Arqueros, F; Asch, T; Asorey, H; Assis, P; Atulugama, B S; Aublin, J; Ave, M; Avila, G; Bäcker, T; Badagnani, D; Barbosa, A F; Barnhill, D; Barroso, S L C; Baughman, B; Bauleo, P; Beatty, J J; Beau, T; Becker, B R; Becker, K H; Bellido, J A; Benzvi, S; Berat, C; Bergmann, T; Bernardini, P; Bertou, X; Biermann, P L; Billoir, P; Blanch-Bigas, O; Blanco, F; Blasi, P; Bleve, C; Blümer, H; Bohácová, M; Bonifazi, C; Bonino, R; Brack, J; Brogueira, P; Brown, W C; Buchholz, P; Bueno, A; Burton, R E; Busca, N G; Caballero-Mora, K S; Cai, B; Camin, D V; Caramete, L; Caruso, R; Carvalho, W; Castellina, A; Catalano, O; Cataldi, G; Cazon, L; Cester, R; Chauvin, J; Chiavassa, A; Chinellato, J A; Chou, A; Chudoba, J; Chye, J; Clark, P D J; Clay, R W; Colombo, E; Conceição, R; Connolly, B; Contreras, F; Coppens, J; Cordier, A; Cotti, U; Coutu, S; Covault, C E; Creusot, A; Criss, A; Cronin, J; Curutiu, A; Dagoret-Campagne, S; Daumiller, K; Dawson, B R; de Almeida, R M; De Donato, C; de Jong, S J; De La Vega, G; Junior, W J M de Mello; Neto, J R T de Mello; De Mitri, I; de Souza, V; Del Peral, L; Deligny, O; Della Selva, A; Fratte, C Delle; Dembinski, H; Di Giulio, C; Diaz, J C; Diep, P N; Dobrigkeit, C; D'Olivo, J C; Dong, P N; Dornic, D; Dorofeev, A; Dos Anjos, J C; Dova, M T; D'Urso, D; Dutan, I; Duvernois, M A; Engel, R; Epele, L; Erdmann, M; Escobar, C O; Etchegoyen, A; Luis, P Facal San; Falcke, H; Farrar, G; Fauth, A C; Fazzini, N; Ferrer, F; Ferrero, A; Fick, B; Filevich, A; Filipcic, A; Fleck, I; Fracchiolla, C E; Fulgione, W; García, B; Gámez, D García; Garcia-Pinto, D; Garrido, X; Geenen, H; Gelmini, G; Gemmeke, H; Ghia, P L; Giller, M; Glass, H; Gold, M S; Golup, G; Albarracin, F Gomez; Berisso, M Gómez; Gonçalves, P; do Amaral, M Gonçalves; Gonzalez, D; Gonzalez, J G; González, M; Góra, D; Gorgi, A; Gouffon, P; Grassi, V; Grillo, A F; Grunfeld, C; Guardincerri, Y; Guarino, F; Guedes, G P; Gutiérrez, J; Hague, J D; Halenka, V; Hamilton, J C; Hansen, P; Harari, D; Harmsma, S; Harton, J L; Haungs, A; Hauschildt, T; Healy, M D; Hebbeker, T; Hebrero, G; Heck, D; Hojvat, C; Holmes, V C; Homola, P; Hörandel, J R; Horneffer, A; Hrabovský, M; Huege, T; Hussain, M; Iarlori, M; Insolia, A; Ionita, F; Italiano, A; Kaducak, M; Kampert, K H; Karova, T; Kasper, P; Kégl, B; Keilhauer, B; Kemp, E; Kieckhafer, R M; Klages, H O; Kleifges, M; Kleinfeller, J; Knapik, R; Knapp, J; Koang, D-H; Krieger, A; Krömer, O; Kuempel, D; Kunka, N; Kusenko, A; La Rosa, G; Lachaud, C; Lago, B L; Lebrun, D; Lebrun, P; Lee, J; de Oliveira, M A Leigui; Letessier-Selvon, A; Leuthold, M; Lhenry-Yvon, I; López, R; Agüera, A Lopez; Bahilo, J Lozano; Lucero, A; García, R Luna; Maccarone, M C; Macolino, C; Maldera, S; Mancarella, G; Manceñido, M E; Mandat, D; Mantsch, P; Mariazzi, A G; Maris, I C; Falcon, H R Marquez; Martello, D; Martínez, J; Bravo, O Martínez; Mathes, H J; Matthews, J; Matthews, J A J; Matthiae, G; Maurizio, D; Mazur, P O; McCauley, T; McEwen, M; McNeil, R R; Medina, M C; Medina-Tanco, G; Melo, D; Menichetti, E; Menschikov, A; Meurer, C; Meyhandan, R; Micheletti, M I; Miele, G; Miller, W; Mollerach, S; Monasor, M; Ragaigne, D Monnier; Montanet, F; Morales, B; Morello, C; Moreno, J C; Morris, C; Mostafá, M; Muller, M A; Mussa, R; Navarra, G; Navarro, J L; Navas, S; Necesal, P; Nellen, L; Newman-Holmes, C; Newton, D; Nhung, P T; Nierstenhoefer, N; Nitz, D; Nosek, D; Nozka, L; Oehlschläger, J; Ohnuki, T; Olinto, A; Olmos-Gilbaja, V M; Ortiz, M; Ortolani, F; Ostapchenko, S; Otero, L; Pacheco, N; Selmi-Dei, D Pakk; Palatka, M; Pallotta, J; Parente, G; Parizot, E; Parlati, S; Pastor, S; Patel, M; Paul, T; Pavlidou, V; Payet, K; Pech, M; Pekala, J; Pelayo, R; Pepe, I M; Perrone, L; Pesce, R; Petrera, S; Petrinca, P; Petrov, Y; Pichel, A; Piegaia, R; Pierog, T; Pimenta, M; Pinto, T; Pirronello, V; Pisanti, O; Platino, M; Pochon, J; Privitera, P; Prouza, M; Quel, E J; Rautenberg, J; Redondo, A; Reucroft, S; Revenu, B; Rezende, F A S; Ridky, J; Riggi, S; Risse, M; Rivière, C; Rizi, V; Roberts, M; Robledo, C; Rodriguez, G; Martino, J Rodriguez; Rojo, J Rodriguez; Rodriguez-Cabo, I; Rodríguez-Frías, M D; Ros, G; Rosado, J; Roth, M; Rouillé-d'Orfeuil, B; Roulet, E; Rovero, A C; Salamida, F; Salazar, H; Salina, G; Sánchez, F; Santander, M; Santo, C E; Santos, E M; Sarazin, F; Sarkar, S; Sato, R; Scherini, V; Schieler, H; Schmidt, A; Schmidt, F; Schmidt, T; Scholten, O; Schovánek, P; Schroeder, F; Schulte, S; Schüssler, F; Sciutto, S J; Scuderi, M; Segreto, A; Semikoz, D; Settimo, M; Shellard, R C; Sidelnik, I; Siffert, B B; Sigl, G

    2008-08-01

    The energy spectrum of cosmic rays above 2.5 x 10;{18} eV, derived from 20,000 events recorded at the Pierre Auger Observatory, is described. The spectral index gamma of the particle flux, J proportional, variantE;{-gamma}, at energies between 4 x 10;{18} eV and 4 x 10;{19} eV is 2.69+/-0.02(stat)+/-0.06(syst), steepening to 4.2+/-0.4(stat)+/-0.06(syst) at higher energies. The hypothesis of a single power law is rejected with a significance greater than 6 standard deviations. The data are consistent with the prediction by Greisen and by Zatsepin and Kuz'min. PMID:18764444

  18. Thermoelectric properties of YMn4+xAl8-x for -2 ≤ x ≤ 2.5

    Seven samples within the series YMn4+xAl8-x (-2.0 ≤ x ≤ 2.5) were synthesized using direct reaction of the elements. The thermoelectric properties of the samples were characterized by measurements of resistivity, thermal conductivity and thermopower. According to transport measurements, slight Mn-deficiency influences the electronic conductivity of the YMn4+xAl8-x system, implying that the electronic structure is marginal to the metal-semiconductor boundary. Furthermore, the ZT values of the samples prepared in this study were low. Experimental results indicated that structurally ordered YMn4Al8 shows metallic conductivity, whereas off-stoichiometric compounds displayed semiconductor-like behavior, at low temperatures.

  19. Design optimization of the characters measurement system of 4 x 2 x 3 multi-slab-amplifier

    Wang Cheng Cheng; Yu Hai Wu; He Shao Bo; Liu Yong; Zhang Xiao Min

    2002-01-01

    The soft aperture slots and multi spatial filters had been used to transmit the same phase of laser beams, the characters measurement system of 4 x 2 x 3 multi-slab-amplifier design has been optimized by a program of Fresnel, where the sizes of pinholes of spatial filters which influence laser propagation have been analyzed here, the design optimization result also discussed, and the methods and results obtained are applicable to the design of high power solid laser amplifier system

  20. Effects of Tb3+ concentration on the La2Sr3(BO3)4: X% Tb3+ polycrystalline nanophosphor

    Mlotswa, D. V.; Madihlaba, R. M.; Koao, L. F.; Onani, M. O.; Dejene, F. B.

    2016-01-01

    A new green phosphor, La2Sr3(BO3)4): x% Tb3+ was fabricated by solution-combustion method using urea as a fuel and ammonium nitrate as an oxidizer. The phosphor was characterised using Fourier transform infrared spectroscopy (FTIR), Thermogravimetric analysis (TGA), Differential scanning calorimetry (DSC), Energy dispersive spectroscopy, X-ray diffraction (XRD), scanning electron microscopy (SEM) and photoluminescence spectroscopy (PL. The results exhibit that La2Sr3(BO3)4): x% Tb3+ phosphor has the strongest excitation at 209 nm with a full-width at half-maximum (FWHM) of 20 nm, and can emit bright green light at 545 nm under 209 nm excitation. The optimum concentration for Tb3+ in La2Sr3(BO3)4): x% Tb3+ is 0.033 mol%. The prominent green luminescence was due to the 5D4-7F5 transition of Tb3+ ion. Herein, the green phosphors are promising good candidates employed in tri-color lamps.

  1. Thermoelectrical properties of (FeNi)xCo4-xSb12 prepared by MA-SPS

    Kegao Liu; Jiuxing Zhang

    2008-01-01

    Bulk skutterudite (FeNi)xCo4-xSb12 with x varying from 0.05 to 1.0 were prepared by mechanical alloying and spark plasma sintering (MA-SPS). The phases of the samples were analyzed by X-ray diffraction, and their thermoelectrical properties were tested by electrical constant instrument and laser thermal constant instrument. The experimental results show that bulk (FeNi)xCo4-xSb12 have the characteristic of typical semiconductor electricity. The addition of FeNi improves the electrical properties to a large extent; the samples of bulk (FeNi)xCo4-xSb12 (x=0.05-1.0) are n-type semiconducting materials; the increase of FeNi content can decrease the absolute value of Seebeck coefficient and therefore decrease the ZT value; FeNi with a higher content when x>0.5 leads to an evident increase in thermal conductivity and also a decrease in ZT value. In general, for ZT value, the optimal added content of FeNi is 0.25-0.5 and the maximum ZT value is 0.2467 when x = 0.5 at 500℃.

  2. Adsorption kinetic regime of cocrystallization. The system ZnC2O4x2H2O-54MnC2O4x2H20

    The ZnC2O4x2H2O finely divided deposit surface properties have been investigated by the methods of electron microscopy, gas adsorption and isotopic exchange in 65Zn 54Mn adsorption from aqueous solutions with Mn2+ initial concentration of 4x10-6 - 5x10-4 mol/l has been studied using the same deposit. Characteristic frequencies of Zn2+ and Mn2+ transitions between layers, zinc and manganese oxalates masses in the first and second layers and local coefficients of cocrystallization of manganese and zinc oxalates in near-surface layers (lambda=0.38+-0.05 and lambda2=0.17+-0.04) have been calculated using representation on successive Zn2+ and Mn2+ transition to three near-surface monolayers and on reverse translation motion. A formula for the connection of lambda sub(γ) coefficients ( is a number of the surface layer) with a layer-to-surface distance has been depived. A possibility of the forecast of a dependence of effective cocrystallization coefficient of impurity with growing crystals on crystal growth rate has been revealed

  3. Magnetic Torque Studies of π-d System κ-(BDH-TTP)2FeX4 (X = Br, Cl)

    Sugii, Kaori; Takai, Kazuyuki; Tsuchiya, Satoshi; Uji, Shinya; Terashima, Taichi; Akutsu, Hiroki; Wada, Atsushi; Ichikawa, Shun; Yamada, Jun-ichi; Enoki, Toshiaki

    2014-02-01

    Systematic measurements of the magnetic torque of organic π-d conductors κ-(BDH-TTP)2FeX4 (X = Br, Cl) have been performed to investigate the magnetic properties. The Fe 3d spins of both salts show antiferromagnetic (AF) orders at low temperatures. A simple two-sublattice model is found to well reproduce the essential features of the torque data in the AF states. The exchange interaction and anisotropic parameter of the ligand field obtained by the simulations are consistent with previous experimental results.

  4. Atomic structure of a stable high-index Ge surface: G2(103)-(4x1)

    Seehofer, L.; Bunk, O.; Falkenberg, G.; Lottermoser, L.; Feidenhans'l, R.; Landemark, E.; Nielsen, M.; Johnson, R.L.

    Based on scanning tunneling microscopy and surface X-ray diffraction, we propose a complex structural model for the Ge(103)-(4 x 1) reconstruction. Each unit cell contains two (103) double steps, which gives rise to the formation of stripes of Ge atoms oriented in the [<(3)over bar 01>] direction....... The stripes and the spaces between them are covered with threefold-coordinated Ge adatoms. Charge is transferred from the bulk-like edge atoms of the double steps to the adatoms. The formation of the reconstruction can be explained in terms of stress relief, charge transfer, and minimization of the...

  5. Finite size giant magnons in the SU(2) x SU(2) sector of AdS4 x CP3

    We use the algebraic curve and Luescher's μ-term to calculate the leading order finite size corrections to the dispersion relation of giant magnons in the SU(2) x SU(2) sector of AdS4 x CP3. We consider a single magnon as well as one magnon in each SU(2). In addition the algebraic curve computation is generalized to give the leading order correction for an arbitrary multi-magnon state in the SU(2) x SU(2) sector.

  6. En strategisk analyse av et taxiselskap i Danmark : en casestudie av 4x48 TaxiNord

    Johansen, Stine Husum

    2012-01-01

    Danmark ble hardt rammet av finanskrisen, og er fortsatt påvirket av dette. Taxibransjen merket i stor grad denne krisen. Jeg går inn i dybden av taxibransjen i Region Hovedstaden ved å se på taxiselskapet 4x48TaxiNord. Deres vognmenn opplever færre turer og dermed lavere inntjeningen. Samtidig så klarer TaxiNord å oppnå lønnsomhet som selskap og de har klart å ekspandere. Jeg benytter meg av en casestudie for å se på denne bransjen, og har utarbeidet forskningsspørsmålet: Hva er årsake...

  7. Formation of a heavy fermion phase in UCu4+xAl8-x by variation of stoichiometry

    Progressive substitution of Cu for Al in UCu4+xAl8-x yields an increasing compression of the unit cell. This results in a reduction of the Neel temperature from TN=42 K for x=0 to TN=15 K for x=1.0. No magnetic ordering is found for x≥1.5. Rather the T-dependence of the resistivity shows a maximum in the range 6 to 15 K and indicates the formation of a Kondo-lattice state. The latter is characterized by heavy fermions (γ(T→0)≅0.8 J/K2 mol for x=1.75). (orig.)

  8. Hydrogen bonds in the structure of BaC2O4xD2O

    The hydrogen bonds in the crystal structure of BaC2O4xD2O were investigated from profile refinement of neutron powder diffraction data. The structure is monoclinic, space group C2/m (No. 12) with the lattice parameters a = 10.0648(3), b = 7.9350(2), c = 6.8503(2) Aa, β = 122.35(2) deg. and Z = 4. The barium atom in the structure is coordinated with ten oxygen atoms, the oxalate ion is planar, and the OD-O hydrogen-bond length is 2.762(5) Aa. (au)

  9. Magnetic and structural properties of AFe4X2 (A = Y, Sc, Lu, and Zr; X = Ge and Si)

    The compound RFe4Ge2 (R=Dy,Ho,Er,Y) have been reported to crystallize with the tetragonal ZrFe4Si2 structure type and to show interesting magnetic properties. In YFe4Ge2, antiferromagnetic ordering with small ordered moment ∝0.63 μB occurs simultaneously with a large (2.5 %) first order structural distortion from tetragonal to orthorhombic at 43.5 K. The presence of a large structural distortion despite a weak antiferromagnetic ordering with low TN and small moments is reminiscent of observations in Fe-arsenides. Here, we present magnetic and structural properties of AFe4X2 (A=Y, Sc, Lu and Zr; X=Ge and Si) based on magnetic susceptibility, specific heat, resistivity and low temperature X-ray diffractometer measurements. Our results indicate the occurrence of a transition in all compounds at critical temperatures between 30 K and 75 K depending on the compounds. There is no systematic relationship between TN and and the lattice parameters of AFe4X2. However, magnetic order and structural distortion seems generally to be connected. The relation between structural, electronic, and magnetic properties is discussed.

  10. Evaluation of some Newly Developed Diploid Hybrids and their Breeding Value in 4x-2x Crosses

    2002-01-01

    The narrow genetic base in potato (Solanum tuberosum L. ) limits the progress in cultivar development.The rich diploid germplasm in the origin center of potato provide a unique resource for improvement of tetraploid potatoes. Seven newly developed diploid hybrids with 2n pollen production, all of which have S.phureja background,were developed and evaluated for their value in potato breeding. They were crossed as male parnets to six tetraploid Solanum tuberosum cultivars,and seeds in large quantity from eleven crosses were obtained. Main agronomic traits ,such as tuber yield ,tuber number,mean tuber weight ,tuber shape ,eye depth, skin smoothness, flesh color, and specific gravity, were measured for 4x-2x tetraploid progenies in seedling generation ,and their parents as well. All of the diploid hybrids had some merit for specific traits and the DH39 was more promising ;high specific gravity trait in some diploid hybrids was successfully introgressed into tetroploid progenies via 4x-2x crosses. These diploid hybrids have potential value in potato breeding.

  11. STM observation of Pt[111](3x3)-Cl and c(4x2)-Cl structures

    Song, M B

    2001-01-01

    The adsorption of chloride on a Pt(111) surface at 90 K has been studied using scanning tunneling microscopy (STM) in ultra-high vacuum environments. The adsorbed chlorine atoms give rise to two different ordered structures, (3x3)-Cl and c(4x2)-Cl, depending on the coverage. It has been determined from the STM image that the absolute coverage of (3x3)-Cl structure is 0.44, which is not in agreement with coverage calibrated by a low energy electron diffraction technique together with an Auger electron spectrometer and a thermal desorption spectrometer. The Cl atoms bound to on-top sites at the Pt(111)(3x3)-Cl surface appeared to effectively perturb the density of states of Pt atoms, as compared with that bound to bridging sites. The other ordered structure, c(4x2)-Cl, with small domain sizes, consists of both on-top and bridge-bonded species with a saturation coverage of 0.5.

  12. Crystal structure of the Sc{sub 2}PbX{sub 4} (X = S and Se) compounds

    Shemet, V.Ya. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave. 13, 43009 Lutsk (Ukraine); Gulay, L.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave. 13, 43009 Lutsk (Ukraine)]. E-mail: gulay@lab.univ.lutsk.ua; Stepien-Damm, J. [W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland); Pietraszko, A. [W. Trzebiatowski Institute of Low Temperature and Structure Research, Polish Academy of Sciences, P.O. Box 1410, 50-950 Wroclaw (Poland); Olekseyuk, I.D. [Department of General and Inorganic Chemistry, Volyn State University, Voli Ave. 13, 43009 Lutsk (Ukraine)

    2006-01-05

    The crystal structure of the Sc{sub 2}PbX{sub 4} (X = S and Se) compounds (space group Pnma, Pearson symbol oP28) were determined by means of X-ray single crystal diffraction (a = 1.1642(4) nm, b = 0.3757(1) nm, c = 1.3711(4) nm, R {sub 1} = 0.0420 (Sc{sub 2}PbS{sub 4})) and X-ray powder diffraction (a = 1.22029(5) nm, b 0.39061(2) nm, c = 1.42801(6) nm, R {sub Bragg} = 0.0954 (Sc{sub 2}PbSe{sub 4})). Both compounds crystallize in the CaFe{sub 2}O{sub 4} structure type. The Sc-centered octahedra and Pb-centered trigonal prisms with two additional atoms form columns along the Y-axis in the structure of the Sc{sub 2}PbX{sub 4} (X = S and Se) compounds.

  13. A New Low-Complexity Decodable Rate-1 Full-Diversity 4 x 4 STBC with Nonvanishing Determinants

    Ismail, Amr; Sari, Hikmet

    2012-01-01

    Space-time coding techniques have become common-place in wireless communication standards as they provide an effective way to mitigate the fading phenomena inherent in wireless channels. However, the use of Space-Time Block Codes (STBCs) increases significantly the optimal detection complexity at the receiver unless the low complexity decodability property is taken into consideration in the STBC design. In this letter we propose a new low-complexity decodable rate-1 full-diversity 4 x 4 STBC. We provide an analytical proof that the proposed code has the Non-Vanishing-Determinant (NVD) property, a property that can be exploited through the use of adaptive modulation which changes the transmission rate according to the wireless channel quality. We compare the proposed code to existing low-complexity decodable rate-1 full-diversity 4 x 4 STBCs in terms of performance over quasi-static Rayleigh fading channels, detection complexity and Peak-to-Average Power Ratio (PAPR). Our code is found to provide the best perf...

  14. Occurrence and core-envelope structure of 1--4x Earth-size planets around Sun-like stars

    Marcy, Geoffrey W; Petigura, Erik A; Isaacson, Howard; Howard, Andrew W; Buchhave, Lars A

    2014-01-01

    Small planets, 1-4x the size of Earth, are extremely common around Sun-like stars, and surprisingly so, as they are missing in our solar system. Recent detections have yielded enough information about this class of exoplanets to begin characterizing their occurrence rates, orbits, masses, densities, and internal structures. The Kepler mission finds the smallest planets to be most common, as 26% of Sun-like stars have small, 1-2 R_e planets with orbital periods under 100 days, and 11% have 1-2 R_e planets that receive 1-4x the incident stellar flux that warms our Earth. These Earth-size planets are sprinkled uniformly with orbital distance (logarithmically) out to 0.4 AU, and probably beyond. Mass measurements for 33 transiting planets of 1-4 R_e show that the smallest of them, R < 1.5 R_e, have the density expected for rocky planets. Their densities increase with increasing radius, likely caused by gravitational compression. Including solar system planets yields a relation: rho = 2.32 + 3.19 R/R_e [g/cc]. ...

  15. Investigation of carbon-coated lithiated Li{sub 4+x}Ti{sub 5}O{sub 12}/C for lithium-ion batteries

    Pan, Mengjie; Zhang, Lin; Gong, Lijun; Liu, Hongbo; Chen, Yuxi, E-mail: yxchen@hnu.edu.cn

    2015-11-15

    Highlights: • Lithiated Li{sub 4+x}Ti{sub 5}O{sub 12}/C with pre-stored active Li ions has been synthesized. • The first-cycle coulombic efficiency of Li{sub 4+x}Ti{sub 5}O{sub 12}/C is over 100%. • Li{sub 4+x}Ti{sub 5}O{sub 12}/C displays excellent cyclic stability and capacity retention. • TiO{sub 2} nanoparticles and carbon coating are necessary for formation of Li{sub 4+x}Ti{sub 5}O{sub 12}/C. - Abstract: Carbon-coated Li{sub 4}Ti{sub 5}O{sub 12} and lithiated Li{sub 4+x}Ti{sub 5}O{sub 12} anode materials have been synthesized using nanosized anatase TiO{sub 2} and commercial TiO{sub 2} with mixed structure as Ti sources, respectively. Microstructural investigation indicates that Li{sub 4}Ti{sub 5}O{sub 12} and Li{sub 4+x}Ti{sub 5}O{sub 12} are covered by amorphous carbon layers with thickness of 2–3 nm. Their electrochemical performance has been evaluated, which indicates that an amount of active Li ions have been pre-stored in the Li{sub 4+x}Ti{sub 5}O{sub 12} lattice during solid-state synthesis, resulting in its first-cycle coulombic efficiency over 100%. Further, Li{sub 4+x}Ti{sub 5}O{sub 12}/C exhibits higher cyclic capacities than Li{sub 4}Ti{sub 5}O{sub 12}/C at different current density. The reversible charge capacity retention of Li{sub 4+x}Ti{sub 5}O{sub 12}/C reaches 98.5% after 100 cycles, which indicates that Li{sub 4+x}Ti{sub 5}O{sub 12}/C is promising candidate anode material for long lifetime lithium-ion batteries. The formation mechanism of Li{sub 4+x}Ti{sub 5}O{sub 12}/C has been discussed, in which the nanosized anatase TiO{sub 2} with high chemical activity and the carbon coating play key roles for the formation of Li{sub 4+x}Ti{sub 5}O{sub 12}/C.

  16. Thermodynamics, dielectric permittivity and phase diagrams of the Rb1-x(NH4xH2PO4 type proton glasses

    S.I. Sorokov

    2010-01-01

    Full Text Available The cluster pseudospin model of proton glasses, which takes into account the energy levels of protons around the PO4 group, the long-range interactions between the hydrogen bonds, and an internal random deformational field is used to investigate thermodynamical characteristics, longitudinal and transverse dielectric permittivities of Rb1-x(ND4xD2PO4 and Rb1-x(NH4xH2AsO4 compounds. A review of experimental and theoretical works on the Rb1-x(NH4xH2PO4 type crystals is presented.

  17. On the Diophantine Equation kx4-(2k+4)x2y2+ky4=-4%关于Diophantine方程kx4-(2k+4)x2y2+ky4=-4

    管训贵; 杜先存

    2014-01-01

    利用Pell方程及同余的性质给出了Diophantine方程G:kx4-(2h+4)x2y2+ ky4=-4仅有整数解(| x |,| y|)=(1,1)的充分条件.证明了:1)若k≠12(mod 16),则Diophantine方程G仅有整数解(|x|,| y|)=(1,1);2)若k=4m,m≡3(mod 4),且2+s或s≡0(mod 4),t≡3,5(mod 8)或s≡2(mod 4),t≡1,7(mod 8),则Diophantine方程G仅有整数解(|x|,|y|)=(1,1),这里s+t4m是Pell方程x2-my2=1的基本解.

  18. System of constants to calculate neutron transport with energy 10-2-4x108 eV

    A description of the library of nuclear data to calculate neutron transport in the energy range 10-2 eV-4x102 MeV (BND-400) is presented. The library contains a seven-group system of data for neutrons of E>10.5 MeV and a standard 26-group system for neutrons with E10.5 MeV, and those for matching with the file of data for neutrons with E<10.5 MeV are briefly described. In the BND-400 complex there are subroutines, which allow one to calculate the cross sections for neutron interaction with nuclei of matter with the help of various methods and models as well as to calculate group cross sections. It also provides output files in the form convenient for work. A brief instruction for BND-400 explotation on the computer BESM-6 is given

  19. Renormalization group analysis and the top quark mass in the SU(4)xO(4) string model

    We perform a two-loop renormalization group analysis for the gauge couplings in the SU(4)xO(4) model. We use the string theory prediction for the unification scale and the experimentally acceptable low energy values for α3 and sin2 Θw, to determine the magnitudes of the various symmetry breaking scales as well as the value of the common gauge coupling at the unification scale. We solve the coupled differential system for the gauge and top and bottom Yukawa couplings, and determine the top mass as a function of two parameters which could be chosen to be the ratio of the Higgs VEV's that give masses to the up and down quarks and the value of the top coupling at the unification scale. We find a relatively heavy top quark mass which lies in the range 130 ≤ mt ≤ 180 GeV. (orig.)

  20. Vacuum energy of M/sup 4/ x S/sup M/ x S/sup N/ in even dimensions

    Gleiser, M.; Jetzer, P.; Rubin, M.A.

    1987-01-01

    We obtain an expression for the one loop effective potential coming from quantum fluctuations of scalars and spin-1/2 fermions in a higher-dimensional manifold of product form M/sup 4/ x S/sup M/ x S/sup N/. In contrast to previous calculations, we consider the case in which the total number of dimensions is even, since this is the relevant case for superstring compactification. A detailed calculation for a ten-dimensional spacetime with two internal 3-spheres is performed, and an approximate static solution for the geometry is found, with the two internal radii being of the order of the Planck length for a sufficiently large number of matter fields. We study the stability of this solution and make some remarks on the possible cosmological implications of our results.

  1. The crystal structure of a new ternary antimonide: TmCu4-xSb2 (x 1.065)

    The crystal structure of the new ternary compound TmCu4-xSb2 (x 1.065) was determined by direct methods from X-ray powder data (diffractometer DRON-3M, Cu Kα-radiation). It crystallizes with the orthorhombic structure type ErFe4Ge2 (low-temperature modification) and is the first representative of this structure type among known antimonides: space group Pnnm, Pearson code oP14-2.13, a = 7.00565(6) A, b = 7.83582(6) A, c = 4.25051(3) A, Z = 2. Investigated structure is an orthorhombically deformed derivative of the ZrFe4Si2 structure type

  2. Symmetry breaking and structural distortions in charged XH4 (X=C, Si, Ge, Sn, and Pb) molecules

    We have investigated the ground-state structures of neutral and charged XH4(X=C, Si, Ge, Sn, and Pb) molecules using the first-principles electronic structure methods. The structure of positively charged molecules for X=Si, Ge, Sn, and Pb is characterized by a severe distortion from tetrahedral structure and an unusual H-H bond while the negatively charged molecules get distorted by pushing two hydrogen atoms away from each other. However, CH4+ and CH4- are exceptions to this behavior. We provide an insight into the symmetry breaking mechanism and unusual H-H bonding using simple electrostatic arguments based on the unequal charge distribution on H atoms. Those charged molecules having unequal charge distribution on H atoms get distorted due to different electrostatic forces between the atoms. We show that the directionality and occupation of the highest occupied molecular orbital play an important role in creating charge asymmetry in these molecules

  3. Dispersion of the second harmonic generation from CdGa2X4 (X = S, Se) defect chalcopyrite: DFT calculations

    Highlights: • Nonlinear optical properties of CdGa2X4 (X = S, Se) were investigated. • The compounds have large uniaxial anisotropy and large negative birefringence. • The second order susceptibility and the first hyperpolarizability were calculated. • CdGa2Se4 posses huge second harmonic generation. - Abstract: All electron full potential linear augmented plane wave method was used for calculating the nonlinear optical susceptibilities of CdGa2X4 (X = S, Se) within the framework of density functional theory. The exchange correlation potential was solved by recently developed modified Becke and Johnson (mBJ) approximation. The crystal structure of CdGa2S4 and CdGa2Se4 reveals a large uniaxial dielectric anisotropy ensuing the birefringence of −0.036 and −0.066 which make it suitable for second harmonic generation. The second order susceptibility |χijk(2)(ω)| and microscopic first hyperpolarizability βijk(ω) were calculated. The calculated |χ123(2)(ω)| and |χ312(2)(ω)| static values for the dominant components found to be 18.36 pm/V and 22.23 pm/V for CdGa2S4 and CdGa2Se4. Both values shifted to be 60.12 pm/V and 108.86 pm/V at λ = 1064 nm. The calculated values of β123(ω) is 6.47 × 10−30 esu at static limit and 12.42 × 10−30 esu at λ = 1064 nm for CdGa2S4, whereas it is 8.82 × 10−30 esu at static limit and 20.51 × 10−30 esu at λ = 1064 nm for CdGa2Se4. The evaluation of second order susceptibilities and first hyperpolarizabilties suggest that CdGa2X4 possess huge second harmonic generation

  4. Unity 4.x cookbook

    Smith, Matt

    2013-01-01

    Cookbook. From beginners to advanced users, from artists to coders, this book is for you and everyone in your team! This book is for anyone who wants to explore a wide range of Unity scripting and multimedia features and to find ready to use solutions to many game features. Programmers can explore multimedia features, and multimedia developers can try their hand at scripting.

  5. Evolution of the surface reconstructions during the growth of an InAs wetting layer on GaAs(001)-c(4 x 4)

    We studied the growth of the first monolayer of InAs on the GaAs(001)-c(4 x 4) surface using a combined UHV-MBE-(RHEED)-STM setup, which provides atomically resolved images of the growth surfaces. For a coverage below about 2/3 of an monolayer of deposited InAs we observe single signatures of the deposited material at the GaAs(001)-c(4 x 4) surface. The number of these signatures is proportional to the amount of deposited InAs. They occur first at the domain boundaries and further at the hollow sites of the GaAs(001)-c(4 x 4) reconstruction. At a coverage of about 2/3 of a monolayer an abrupt phase transition occurs in the RHEED. Also the STM images changes completely from the c(4 x 4) reconstruction to a flat topmost layer, showing an (n x 3) periodicity along[110] direction. The detailed analysis of this layer exhibits an in-line (4 x 3) reconstruction alternating with a brick-lined c(4 x 6) reconstruction, shifted to each other along the[-110] direction by the insertion of an (6 x 3) surface unit cell. The stoichiometry of the (4 x 3) could be determined to In2/3Ga1/3As for the topmost layer and the complete structural model for this surface reconstruction can be given, due to comparison of the STM images with DFT-calculations. On top of this layer, the InAs grows in pure stoichiometry and forms chains and 2D islands with α2(2 x 4) and β2(2 x 4) reconstructions.

  6. Synthesis and Thermoelectric Properties of La1- z Yb z Fe4- x Ni x Sb12 Skutterudites

    Jeon, Bong-Jun; Shin, Dong-Kil; Kim, Il-Ho

    2016-03-01

    p-Type La1- z Yb z Fe4- x Ni x Sb12 (0.25 ≤ z ≤ 0.75 and 0.25 ≤ x ≤ 0.5) skutterudites were prepared by encapsulated melting and hot pressing, and the effects of filling and substitution (charge compensation) on the transport and thermoelectric properties were examined. The single-phase skutterudite was successfully synthesized through La/Yb double filling and Ni substitution for Fe. However, a small amount of FeSb2 was detected for La0.25Yb0.75Fe3.75 Ni0.25Sb12, which was attributed to insufficient charge compensation due to deficiency of substitution of Ni for Fe, as well as higher filling fraction of Yb with lower valence than La. The carrier concentration and electrical conductivity decreased with increasing La and Ni contents, with La serving to provide more excess electrons and Ni mediating charge compensation. The electrical conductivity decreased with increasing temperature, indicating that La1- z Yb z Fe4- x Ni x Sb12 skutterudites were degenerate semiconductors. The positive values of the Hall coefficient and the Seebeck coefficient meant that the major carriers were holes with p-type conduction. The Seebeck coefficient increased with increasing temperature, showing peak values ranging from 723 K to 823 K, which increased with increasing La and Ni contents. The maximum power factor of 2.9 mW m-1 K-2 was obtained for La0.75Yb0.25 Fe3.75Ni0.25Sb12. The thermal conductivity increased at temperatures above 623 K due to bipolar conduction, and the lattice thermal conductivity decreased with increasing filling fraction of Yb, indicating that the Yb filling was more effective at reducing the lattice thermal conductivity than the La filling. The electronic thermal conductivity decreased with increasing La and Ni contents due to the decrease in the carrier concentration. The dimensionless figure of merit ( ZT) showed peak values at 723 K, attributed to the decreased Seebeck coefficient (or power factor) and the increased thermal conductivity due to bipolar

  7. Couples Magnetic and Structural Transitions in High-Purity Dy and Gd5SbxGe4-x

    Alexander S. Chernyshov

    2006-08-09

    Magnetic materials exhibiting magnetic phase transitions simultaneously with structural rearrangements of their crystal lattices hold a promise for numerous applications including magnetic refrigeration, magnetomechanical devices and sensors. We undertook a detailed study of a single crystal of dysprosium metal, which is a classical example of a system where magnetic and crystallographic sublattices can be either coupled or decoupled from one another. Magnetocaloric effect, magnetization, ac magnetic susceptibility, and heat capacity of high purity single crystals of dysprosium have been investigated over broad temperature and magnetic field intervals with the magnetic field vector parallel to either the a- or c-axes of the crystal. Notable differences in the behavior of the physical properties when compared to Dy samples studied in the past have been observed between 110 K and 125 K, and between 178 K and {approx}210 K. A plausible mechanism based on the formation of antiferromagnetic clusters in the impure Dy has been suggested in order to explain the reduction of the magnetocaloric effect in the vicinity of the Neel point. Experimental and theoretical investigations of the influence of commensurability effects on the magnetic phase diagram and the value of the magnetocaloric effect have been conducted. The presence of newly found anomalies in the physical properties has been considered as evidence of previously unreported states of Dy. The refined magnetic phase diagram of dysprosium with the magnetic field vector parallel to the a-axis of a crystal has been constructed and discussed. The magnetic and crystallographic properties of Gd{sub 5}Sb{sub x}Ge{sub 4-x} pseudo-binary system were studied by x-ray diffraction (at room temperature), heat capacity, ac-magnetic susceptibility, and magnetization in the temperature interval 5-320 K in magnetic fields up to 100 kOe. The magnetic properties of three composition (x = 0.5, 1,2) were examined in detail. The Gd{sub 5

  8. Electronic Transport and Thermoelectric Properties of p-Type Nd z Fe4- x Co x Sb12 Skutterudites

    Shin, Dong-Kil; Kim, Il-Ho

    2016-03-01

    p-Type Nd z Fe4- x Co x Sb12 ( z = 0.8, 0.9, 1.0 and x = 0, 0.5, 1.0) skutterudites were synthesized by encapsulated melting and annealing, and consolidated with hot pressing. The effects of Nd filling and Co substitution for Fe (charge compensation) on the electronic transport and the thermoelectric properties of the skutterudites were examined. A few secondary phases such as Sb and FeSb2 were formed together with the skutterudite phase, but the formation was suppressed with increasing Nd and Co contents. It was confirmed that Nd was filled in the void and Co was substituted for Fe in all specimens, because the lattice constant increased with increasing Nd content and decreased with increasing Co content. The electrical conductivity of all specimens decreased slightly with increasing temperature, showing degenerate semiconductor characteristics. The Hall and the Seebeck coefficients showed positive signs, indicating that the major carriers were holes ( p-type conduction). The Seebeck coefficients were increased due to the decrease in the carrier concentration with increasing Nd and Co contents, while the electrical conductivity and the thermal conductivity were decreased. As a result, the dimensionless figure-of-merit, ZT, was improved by Nd filling and Co substitution, and a maximum ZT = 0.91 was obtained at 723 K for Nd0.9Fe3.5Co0.5Sb12.

  9. A theoretical study of the thermodynamic properties of YMgX4 (X=Co, Ni, Cu) compounds

    The stability, electronic structures, elastic and thermal properties of the ternary YMgX4 (X=Co, Ni, Cu) compounds are investigated by first principle calculations in combination with the quasi-harmonic Debye model. The three compounds are predicted to be stable according to the formation enthalpies (ΔH), elastic constants (cij) and phonon dispersion models. The elastic constants and polycrystalline elastic moduli reveal the relatively low anisotropy of these compounds. The electronic structures and bonding characters are analyzed by the electron densities of states and difference charge densities in the (110) plane. The comparisons between the phonon density of state and the quasi-harmonic Debye model imply the heat capacities (Cv) and vibrational entropies (S) are close for YMgCo4 and YMgCu4, whereas large deviation for YMgNi4. A possible reason is that YMgNi4 has the slightly strong directional bondings, relative to YMgCo4 and YMgCu4

  10. Structural and magnetic properties of the mixed quantum antiferromagnet Cs2CuCl4-xBrx

    The two compounds, Cs2CuCl4 and Cs2CuBr4, have been classified as quasi-two-dimensional quantum antiferromagnets. Cs2CuCl4 shows long-range magnetic order, which can be described as a Bose-Einstein condensation of magnons, i.e., delocalized triplet excitations, whereas the iso-structural compound Cs2CuBr4, exhibits plateaus in the magnetization, indicating the localization of triplets. Here we present a systematic study of the magnetic properties in the Cs2CuCl4-xBrx (0 ≤ x≤ 4) mixed system. All crystals were synthesized by a solution-growth method. Two structural variants - an A-type orthorhombic and a B-type tetragonal - were detected in this system depending on the growth conditions. A detailed structural phase diagram has been constructed, based on X-ray Rietveld refinement, SEM and thermal analysis. χ(T) measurements of crystals near the end members of the series reveal a broad maximum at Tmax indicative of quasi-2D short range correlations. While for the Cl-rich system 0≤x≤0.8, Tmax slightly increases with increasing Br-, a much stronger increase of Tmax.is observed for the Br-rich system for 2.8≤x≤4.0.

  11. Surfactant action in heteroepitaxy: Growth of Co on (4x4)Pb/Cu(111) studied by LEED and STM

    The magnetic properties of ultrathin Co films and Co/Cu heterostructures grown on Cu(111) have been shown to improve when Pb is used as a surfactant: the thickness range of Co films displaying perpendicular magnetic anisotropy is extended and a complete antiferromagnetic coupling between them is made possible. In this paper, we aim to understand the origin of these magnetic properties by illuminating the crystallographic structure and morphology of the films. We apply low-energy electron diffraction (LEED) and scanning tunneling microscopy (STM) to ultrathin epitaxial Co films grown on the Cu(111) surface precovered by 1 monolayer (ML) of Pb in the (4x4) superstructure. The Pb layer is found to segregate to the surface of the growing films and STM images show that the growth of Co proceeds in the layer-by-layer mode for coverages higher than 2 ML. For lower coverages, a coexistence of 1 ML and 2 ML high islands is observed on the terraces. A quantitative comparison of experimental LEED spectra shows that the structural transition from fcc to hcp stacking with increasing thickness of the Co films deposited on the Cu(111) substrate is not significantly affected by the surfactant. Instead, the latter induces the formation of sharp interfaces that favor the interface contribution to the magnetic anisotropy and allow the growth of rather smooth films with well-defined thicknesses

  12. Periodicity, Electronic Structures, and Bonding of Gold Tetrahalides [AuX4]- (X = F, Cl, Br, I, At, Uus).

    Li, Wan-Lu; Li, Yong; Xu, Cong-Qiao; Wang, Xue-Bin; Vorpagel, Erich; Li, Jun

    2015-12-01

    Systematic theoretical and experimental investigations have been performed to understand the periodicity, electronic structures, and bonding of gold halides using tetrahalide [AuX4](-) anions (X = F, Cl, Br, I, At, Uus). The [AuX4](-) (X = Cl, Br, I) anions were experimentally produced in the gas phase, and their negative-ion photoelectron spectra were obtained, exhibiting rich and well-resolved spectral peaks. As expected, Au-X bonds in such series contain generally increasing covalency when halogen ligands become heavier. We calculated the adiabatic electron detachment energies as well as vertical electron detachment energies using density functional theory methods with scalar relativistic and spin-orbit coupling effects. The computationally simulated photoelectron spectra are in good agreement with the experimental ones. Our results show that the trivalent Au(III) oxidation state becomes progressively less stable while Au(I) tends to be preferred when the halides become heavier along the Periodic Table. This series of molecules provides an example for manipulating the oxidation state of metals in complexes through ligand design. PMID:26550845

  13. A theoretical study of the thermodynamic properties of YMgX4 (X=Co, Ni, Cu compounds

    Ruizi Li

    2014-09-01

    Full Text Available The stability, electronic structures, elastic and thermal properties of the ternary YMgX4 (X=Co, Ni, Cu compounds are investigated by first principle calculations in combination with the quasi-harmonic Debye model. The three compounds are predicted to be stable according to the formation enthalpies (ΔH, elastic constants (cij and phonon dispersion models. The elastic constants and polycrystalline elastic moduli reveal the relatively low anisotropy of these compounds. The electronic structures and bonding characters are analyzed by the electron densities of states and difference charge densities in the (110 plane. The comparisons between the phonon density of state and the quasi-harmonic Debye model imply the heat capacities (Cv and vibrational entropies (S are close for YMgCo4 and YMgCu4, whereas large deviation for YMgNi4. A possible reason is that YMgNi4 has the slightly strong directional bondings, relative to YMgCo4 and YMgCu4.

  14. Defect Chemistry of a Zinc-Doped Lepidocrocite Titanate CsxTi2−x/2Znx/2O4 (x = 0.7) and its Protonic Form

    Gao, Tao; Fjellvåg, Helmer; Norby, Poul

    2009-01-01

    A zinc-doped layered titanate CsxTi2−x/2Znx/2O4 (x = 0.7) with lepidocrocite (γ-FeOOH)-type layered structure was prepared via solid-state calcination. A complete extraction of both lattice Zn atoms and interlayer Cs ions was observed upon acid exchange, producing a protonic form H2xTi2−x/2x/2O4·H2...... protonic titanate H2xTi2−x/2x/2O4·H2O readily underwent delamination to produce its molecular single sheets Ti1−δδO24δ− (δ = 0.175) with distinctive two-dimensional morphology and small thickness (1 nm), suggesting promising applications in the assembly of functional nanostructures....

  15. Crystal Structure and Dynamics of K$_{2-x}$(NH$_{4}$)$_{x}$SeO$_{4}$ Mixed Crystals Studied by X-ray and Neutron Scattering

    Smirnov, L S; Loose, A; Martínez-Sarrion, M L; Melnyk, G; Mestres, L; Natkaniec, I; Nowak, D; Pawlukojc, A; Wozniak, K; Zink, N

    2006-01-01

    The K$_{2-x}$(NH$_{4}$)$_{x}$SeO$_{4}$ mixed crystals have been studied by powder X-ray and neutron diffraction and inelastic incoherent neutron scattering in a wide temperature range from 300 to 16 K. No phase transition is observed in (NH$_{4}$)$_{2}$SeO$_{4}$ in the range from room temperature to 20 K. The reorientation potential barriers of ammonium ions in the K$_{2-x}$(NH$_{4}$)$_{x}$SeO$_{4}$ mixed crystals increase with the increasing concentration of ammonium ions.

  16. Thermoelectric Properties of p-Type La1- z Pr z Fe4- x Co x Sb12 Skutterudites

    Song, Kwon-Min; Shin, Dong-Kil; Kim, Il-Ho

    2016-03-01

    p-Type La1- z Pr z Fe4- x Co x Sb12 skutterudites were prepared by encapsulated melting, quenching, annealing, and hot pressing. The skutterudite phase was successfully synthesized but small amounts of FeSb2 and (La,Pr)Sb2 secondary phases were also observed, especially for the Co-substituted specimens. Carrier concentration decreased with increasing Pr and Co content. Electrical conductivity decreased with increasing temperature, showing that all specimens were heavily-doped semiconductors. Electrical conductivity also decreased with increasing Pr and Co content. The Hall and the Seebeck coefficients revealed that all specimens had p-type characteristics. Seebeck coefficients increased with increasing temperature, with maximum values occurring between 723 and 823 K. The maximum power factor ( PF) was 3.1 m Wm-1 K-2, at 823 K and 723 K for La0.75Pr0.25Fe4Sb12 and La0.75Pr0.25 Fe3.75Co0.25Sb12, respectively. Thermal conductivity decreased with increasing Pr and Co content, and increased because of bipolar conduction at temperatures above 723 K. For a fixed Co content, lattice thermal conductivity decreased with increasing Pr content; this may be attributed to a larger contribution from Pr than from La to the decrease in lattice thermal conductivity. The dimensionless figure of merit ( ZT) had maximum values of 0.83 at 823 K for La0.75Pr0.25Fe4Sb12 and 0.81 at 723 K for La0.75Pr0.25Fe3.75Co0.25Sb12.

  17. AdS4 x CP3 superstring as OSp(4|6)/(SO(1,3) x U(3)) sigma-model in conformal basis

    Basic features of Lagrangian formulation for AdS4 x CP3 superstring in the framework of OSp(4|6)/(SO(1,3) x U(3)) sigma-model approach are reviewed with the emphasis on realization OSp(4|6) background isometry superalgebra as D = 3 N = 6 superconformal algebra.

  18. Identification of Four Novel Synonymous Substitutions in the X-Linked Genes Neuroligin 3 and Neuroligin 4X in Japanese Patients with Autistic Spectrum Disorder

    Kumiko Yanagi

    2012-01-01

    Full Text Available Mutations in the X-linked genes neuroligin 3 (NLGN3 and neuroligin 4X (NLGN4X were first implicated in the pathogenesis of X-linked autism in Swedish families. However, reports of mutations in these genes in autism spectrum disorder (ASD patients from various ethnic backgrounds present conflicting results regarding the etiology of ASD, possibly because of genetic heterogeneity and/or differences in their ethnic background. Additional mutation screening study on another ethnic background could help to clarify the relevance of the genes to ASD. We scanned the entire coding regions of NLGN3 and NLGN4X in 62 Japanese patients with ASD by polymerase chain reaction-high-resolution melting curve and direct sequencing analyses. Four synonymous substitutions, one in NLGN3 and three in NLGN4X, were identified in four of the 62 patients. These substitutions were not present in 278 control X-chromosomes from unrelated Japanese individuals and were not registered in the database of Single Nucleotide Polymorphisms build 132 or in the Japanese Single Nucleotide Polymorphisms database, indicating that they were novel and specific to ASD. Though further analysis is necessary to determine the physiological and clinical importance of such substitutions, the possibility of the relevance of both synonymous and nonsynonymous substitutions with the etiology of ASD should be considered.

  19. The role of ion pairs in the second-order NLO response of 4-X-1-methylpiridinium salts.

    Tessore, Francesca; Cariati, Elena; Cariati, Franco; Roberto, Dominique; Ugo, Renato; Mussini, Patrizia; Zuccaccia, Cristiano; Macchioni, Alceo

    2010-02-01

    A series of 4-X-1-methylpyridinium cationic nonlinear optical (NLO) chromophores (X = (E)-CH=CHC(6)H(5); (E)-CH=CHC(6)H(4)-4'-C(CH(3))(3); (E)-CH=CHC(6)H(4)-4'-N(CH(3))(2); (E)-CH=CHC(6)H(4)-4'-N(C(4)H(9))(2); (E,E)-(CH=CH)(2)C(6)H(4)-4'-N(CH(3))(2)) with various organic (CF(3)SO(3)(-), p-CH(3)C(6)H(4)SO(3)(-)), inorganic (I(-), ClO(4)(-), SCN(-), [Hg(2)I(6)](2-)) and organometallic (cis-[Ir(CO)(2)I(2)](-)) counter anions are studied with the aim of investigating the role of ion pairing and of ionic dissociation or aggregation of ion pairs in controlling their second-order NLO response in anhydrous chloroform solution. The combined use of electronic absorption spectra, conductimetric measurements and pulsed field gradient spin echo (PGSE) NMR experiments show that the second-order NLO response, investigated by the electric-field-induced second harmonic generation (EFISH) technique, of the salts of the cationic NLO chromophores strongly depends upon the nature of the counter anion and concentration. The ion pairs are the major species at concentration around 10(-3) M, and their dipole moments were determined. Generally, below 5x10(-4) M, ion pairs start to dissociate into ions with parallel increase of the second-order NLO response, due to the increased concentration of purely cationic NLO chromophores with improved NLO response. At concentration higher than 10(-3) M, some multipolar aggregates, probably of H type, are formed, with parallel slight decrease of the second-order NLO response. Ion pairing is dependent upon the nature of the counter anion and on the electronic structure of the cationic NLO chromophore. It is very strong for the thiocyanate anion in particular and, albeit to a lesser extent, for the sulfonated anions. The latter show increased tendency to self-aggregate. PMID:20029883

  20. Atomic structure of carbon-induced Si(001)c(4x4) reconstruction as a Si-Si homodimer and C-Si heterodimer network

    A combination of low-energy electron diffraction, x-ray and ultraviolet photoelectron spectroscopy, and scanning-tunneling microscopy studies, in conjunction with ab initio calculations leads us to suggest a model for the carbon (C)-induced Si(001)c(4x4) atomic structure. This surface superstructure is obtained in a defined range of C2H4 exposures at 600 deg. C. Experimental probes show that the c(4x4) superstructure involves C atoms in both surface and subsurface sites. This is reflected in well-marked features in photoemission valence- and core-level spectra. Surface carbon atoms are stabilized in Si-C heterodimers, with a surface density of about 0.25 monolayer (ML) [i.e., two C atoms per c(4x4) unit cell of eight atoms]. In the subsurface region, carbon atoms substitute for Si atoms in well-defined sites of the third or fourth layers of the Si substrate. The subsurface C density increases with C2H4 exposure time up to a limit value of about 0.5 ML, within the c(4x4) surface structure. Further exposure disrupts the c(4x4) reconstruction and leads to a (2x1) low-energy electron diffraction pattern. Interaction with atomic hydrogen shows that the surface contains a mixture of heterodimers (Si-C) and homodimers (Si-Si), with an 1:1 proportion. These assignments are supported by first-principle calculations, which yield valence band and core level states in fairly good agreement with the experiment. Furthermore, total energy calculations strongly favor C incorporation in surface Si-C dimers and in third and fourth layer sites, and rule out C incorporation in sites of the second Si layer. The most stable c(4x4) surface configuration, suggested by our calculations, consists of alternate Si-C and Si-Si dimer lines. In such a configuration, surface carbon atoms in Si-C dimers induce a surface stress that leads to charge redistribution and atomic relaxation of the adjacent Si-Si dimers, consistent with scanning-tunneling microscopy images. Additional C atoms (in excess

  1. Disentanglement of static and dynamic magnetism in itinerant AFe4X2 systems studied by muon spin relaxation and Moessbauer spectroscopy

    The AFe4X2 (A=Y,Lu,Zr; X=Ge,Si) family of transition metal tetrels has shown to be a promising candidate for studying the change of the electronic ground state under chemical substitution. Within the ZrFe4Si2-type structure (P42/mnm), the iron atoms are arranged in chains of edge-linked tetrahedral. Their structure is prone for reduced dimensionality or frustration and is thus expected to lead to emergent phenomena near a quantum critical point. In this talk, we give an overview of our recent experimental findings from Muon Spin Relaxation and Moessbauer Spectroscopy experiments for a variety of AFe4X2. We focus on the ZrFe4Si2 compound, where we observe electronic spin fluctuations already at 100 K whereas long-range magnetic order sets in only below 10 K.

  2. The Dynamics of Ammonium Ions in K_{1-x}(NH_{4})_{x}Cl Mixed Crystals by the Neutron Scattering Study

    Smirnov, L S; Shuvalov, L A; Dolbinina, V V

    2004-01-01

    The study of vibrational spectrum of the K_{1-x}(NH_{4})_{x}Cl mixed crystals in dynamically disordered cubic alpha-phase at 10 K is carried out by means of inelastic incoherent neutron scattering on the NERA-PR time-of-flight spectrometer set at the IBR-2 reactor (JINR, Dubna). It is shown that low-energy modes of ammonium ions with energies 19-23 and 62-63 cm^{-1} at 10 K are observed only within disordered cubic alpha-phase and are absent in ordered cubic delta-phase of NH_{4}Cl. The energies of local translation and libration modes of ammonium ions are determined in the alpha- and delta-phases of the K_{1-x}(NH_{4})_{x}Cl mixed crystals.

  3. Equilibrium coefficient of cocrystallization in the system ZnC2O4x2H2O-Mn(2)-H2O

    To determine the equilibrium volume coefficient of cocrystallization (D) of the Mn(2+) impurity, labelled by 54Mn radionuclide with sediment ZpC2O4x2H2O (Mn concentration in aqueous solution is 4x10-6 - 1.86x10-3 mol/l) three methods are used: 1) spontaneous sediment ripening; 2) sediment ripening alternating with wearing of a solid phase; 3) technique of express D determination for difficultly soluble substances in open systems. It is shown that the 1 and 2 methods lead to the same stationary state of the system for which D--0.100+-0.006, and D magnitude is not dependent on initial Mn concentration. The 3 method gives overstated magnitudes of D=O.16+-0.04

  4. Design, synthesis and characterization of the advanced tritium breeder: Li4+xSi1-xAlxO4 ceramics

    Zhao, Linjie; Long, Xinggui; Chen, Xiaojun; Xiao, Chengjian; Gong, Yu; Guan, Qiushi; Li, Jiamao; Xie, Lei; Chen, Xiping; Peng, Shuming

    2015-12-01

    Li4+xSi1-xAlxO4 solid solutions which were designed as the advanced tritium breeder were obtained by solid state reactions. Samples were systematically characterized by various techniques. XRD, neutron diffraction and Raman results showed that the Aluminum substituted silicon into the Li4SiO4 lattice and Li+ interstitials formed as a result of charge compensation. Rietveld refinements of neutron diffraction showed that the crystalline structure had been expanded as Al-doped. Moreover, the lithium atom density, thermal conductivity and the mechanical property of the Li4+xSi1-xAlxO4 ceramics were improved relative to the Li4SiO4.

  5. Structure of hafnium and ammonium double sulphate Hf(SO4)2x2(NH4)2SO4x4H2O

    X-ray structural study of hafnium and ammonium double sulfate (NH4)4Hf(SO4)4 x 4H2O (diffractometer ''Syntex R2'', lambda Mo, heavy atom method, anisotropic specification R=0.052 according to 2330 reflections) has been carried out. The crystals are monoclinic, a=22.264, b=7.356, c=18.065 A, #betta#=138.33 deg, gr. C2/c. The structure is built of complex anions [Hf(SO4)4 x (H2O)2]4-, cations NH4+ and water molecules. Hf - O distances in hafnium dodecahedron are 2.067-2.283 A. Valent angles of the compounds are presented

  6. Cernunnos interacts with the XRCC4 x DNA-ligase IV complex and is homologous to the yeast nonhomologous end-joining factor Nej1.

    Callebaut, Isabelle; Malivert, Laurent; Fischer, Alain; Mornon, Jean-Paul; Revy, Patrick; de Villartay, Jean-Pierre

    2006-05-19

    DNA double strand breaks are considered as the most harmful DNA lesions and are repaired by either homologous recombination or nonhomologous end joining (NHEJ). A new NHEJ factor, Cernunnos, has been identified, the defect of which leads to a severe immunodeficiency condition associated with microcephaly and other developmental defects in humans. This presentation is reminiscent to that of DNA-ligase IV deficiency and suggests a possible interplay between Cernunnos and the XRCC4 x DNA-ligase IV complex. We show here that Cernunnos physically interacts with the XRCC4 x DNA-ligase IV complex. Moreover, a combination of sensitive methods of sequence analysis revealed that Cernunnos can be associated with the XRCC4 family of proteins and that it corresponds to the genuine homolog of the yeast Nej1 protein. Altogether these results shed new lights on the last step, the DNA religation, of the NHEJ pathway. PMID:16571728

  7. Technique and considerations in the use of 4x1 ring high-definition transcranial direct current stimulation (HD-tDCS).

    Villamar, Mauricio F; Volz, Magdalena Sarah; Bikson, Marom; Datta, Abhishek; Dasilva, Alexandre F; Fregni, Felipe

    2013-01-01

    High-definition transcranial direct current stimulation (HD-tDCS) has recently been developed as a noninvasive brain stimulation approach that increases the accuracy of current delivery to the brain by using arrays of smaller "high-definition" electrodes, instead of the larger pad-electrodes of conventional tDCS. Targeting is achieved by energizing electrodes placed in predetermined configurations. One of these is the 4x1-ring configuration. In this approach, a center ring electrode (anode or cathode) overlying the target cortical region is surrounded by four return electrodes, which help circumscribe the area of stimulation. Delivery of 4x1-ring HD-tDCS is capable of inducing significant neurophysiological and clinical effects in both healthy subjects and patients. Furthermore, its tolerability is supported by studies using intensities as high as 2.0 milliamperes for up to twenty minutes. Even though 4x1 HD-tDCS is simple to perform, correct electrode positioning is important in order to accurately stimulate target cortical regions and exert its neuromodulatory effects. The use of electrodes and hardware that have specifically been tested for HD-tDCS is critical for safety and tolerability. Given that most published studies on 4x1 HD-tDCS have targeted the primary motor cortex (M1), particularly for pain-related outcomes, the purpose of this article is to systematically describe its use for M1 stimulation, as well as the considerations to be taken for safe and effective stimulation. However, the methods outlined here can be adapted for other HD-tDCS configurations and cortical targets. PMID:23893039

  8. Contrasting the Material Chemistry of Cu2ZnSnSe4 and Cu2ZnSnS(4-x)Sex

    Aguiar, Jeffery A.; Patel, Maulik; Aoki, Toshihiro; Wozny, Sarah; Al-Jassim, Mowafak

    2016-06-01

    Earth-abundant sustainable inorganic thin-film solar cells, independent of precious elements, pivot on a marginal material phase space targeting specific compounds. Advanced materials characterization efforts are necessary to expose the roles of microstructure, chemistry, and interfaces. Herein, the earth-abundant solar cell device, Cu2ZnSnS(4-x)Sex, is reported, which shows a high abundance of secondary phases compared to similarly grown Cu2ZnSnSe4.

  9. Model building on the non-factorisable type IIA T{sup 6}/(Z{sub 4} x ΩR) orientifold

    Seifert, Alexander; Honecker, Gabriele [Institute for Physics (WA THEP) and Cluster of Excellence PRISMA, Johannes Gutenberg University, Mainz (Germany)

    2016-04-15

    We construct global semi-realistic supersymmetric models with intersecting D6-branes on the non-factorisable orientifold T{sup 6}/(Z{sub 4} x ΩR). The non-factorisable structure gives rise to differences compared to the factorisable case: additional conditions for the three-cycles to be Lagrangian and extra constraints on the wrapping numbers for building fractional cycles. (copyright 2016 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  10. Ordering of CeIII/CeIV and interstitial oxygens in CeTaO4+x (x ∼ 0.17) superstructure

    A structural model for CeTaO4+x (x ∼ 0.17) or alternately Ce4IIICe2IVTa6O25 (monoclinic, P21, a = 7.616(2), b = 16.459(5), c = 7.704(2) angstrom, β = 102.48(2)degree, Z = 2) is derived from X-ray powder diffraction data. The starting model was a 3 x b superstructure of CeTaO4+x (x = 0.0) with excess oxygen atoms occupying interstices between the Ce atom layers consistent with the electron diffraction determined space group symmetry P21. Unexpectedly, the four Ce atoms surrounding the interstitial oxygen are not oxidized. During the refinement the model was forced to be chemically plausible by restraining bond valence sums, bond lengths, and O-O distances. This was necessary due to the very weak scattering contribution to the XRD profile by oxygen atoms. The mechanism for oxidation of the subject phase from CeTaO4+x (x = 0.0) is discussed and a reason for the limiting composition for this phase is proposed

  11. Determining the effect of Ru substitution on the thermal stability of CeFe[subscript 4-x]Ru[subscript x]Sb[subscript 12

    Sigrist, Jessica A.; Walker, James D.S.; Hayes, John R.; Gaultois, Michael W.; Grosvenor, Andrew P. (Saskatchewan)

    2011-11-14

    The ternary, rare-earth filled (RE) Skutterudites (REM{sub 4}Pn{sub 12}; M = Fe-Os; Pn = P-Sb) have been proposed for use in high-temperature thermoelectric devices to convert waste heat to useful power. CeFe{sub 4}Sb{sub 12} has been one of the most popular materials proposed for this application; however, it oxidizes at relatively low temperatures. The thermal stability of Skutterudites can be enhanced by selective substitution of the constituent elements and Eu(Fe,Ru){sub 4}Sb{sub 12} variants have been found to oxidize at temperatures above that of CeFe{sub 4}Sb{sub 12}. Unfortunately, these materials have poor thermoelectric properties. In this study, the thermal stability of CeFe{sub 4-x}Ru{sub x}Sb{sub 12} was examined depending on the value of x. (These compounds have similar thermoelectric properties to those of CeFe{sub 4}Sb{sub 12}.) It has been found by use of TGA and XANES that the temperature at which point CeFe{sub 4-x}Ru{sub x}Sb{sub 12} oxidizes increases with greater Ru substitution. XANES was also used to confirm the general charge assignment of Ce{sup 3+}Fe{sub 4-x}{sup 2+}Ru{sub x}{sup 2+}Sb{sub 12}{sup 1-}.

  12. Preparation and chemical properties of the skutterudites (Ce-Yb) yFe4-x(Co/Ni) xSb12

    The double-filled skutterudites Ce y/2Yb y/2Fe4-xCo xSb12 and Ce y/2Yb y/2Fe4-xNi xSb12 have been synthesized as single phase materials. The evolution of the lattice parameters and of the filling fractions with substitutions on the transition metal site have been studied by X-ray diffraction and electron probe microanalysis, respectively. Both results were compared to that of single filled series (Ce/Yb) yFe4-x(Co/Ni) xSb12. It shows that double-filled skutterudites can be understood as a solid solution between single filled ones. The valence states of Ce and Yb in all series have been studied using X-ray absorption spectroscopy at the L3 edges, and we discuss their relationships with structural parameters. Ce is always trivalent, whereas Yb valence state decreases as Yb fraction increases. No distortion of the environment or sub-position of Yb in the cage have been seen by neutron diffraction. The Seebeck coefficient has been measured using a home made apparatus from 120 K to 300 K. It shows a crossover from p- to n-type conductivity for Co or Ni rich skutterudites in the six series. We discuss the influence on the room temperature thermopower of valence states, filling fractions and substitution rate on the transition metal site. Thermopower seems to be only driven by charge carriers concentration

  13. Hf3Fe4Sn4 and Hf9Fe4-xSn10+x: Two stannide intermetallics with low-dimensional iron sublattices

    Calta, Nicholas P.; Kanatzidis, Mercouri G.

    2016-04-01

    This article reports two new Hf-rich intermetallics synthesized using Sn flux: Hf3Fe4Sn4 and Hf9Fe4-xSn10+x. Hf3Fe4Sn4 adopts an ordered variant the Hf3Cu8 structure type in orthorhombic space group Pnma with unit cell edges of a=8.1143(5) Å, b=8.8466(5) Å, and c=10.6069(6) Å. Hf9Fe4-xSn10+x, on the other hand, adopts a new structure type in Cmc21 with unit cell edges of a=5.6458(3) Å, b=35.796(2) Å, and c=8.88725(9) Å for x=0. It exhibits a small amount of phase width in which Sn substitutes on one of the Fe sites. Both structures are fully three-dimensional and are characterized by pseudo one- and two-dimensional networks of Fe-Fe homoatomic bonding. Hf9Fe4-xSn10+x exhibits antiferromagnetic order at TN=46(2) K and its electrical transport behavior indicates that it is a normal metal with phonon-dictated resistivity. Hf3Fe4Sn4 is also an antiferromagnet with a rather high ordering temperature of TN=373(5) K. Single crystal resistivity measurements indicate that Hf3Fe4Sn4 behaves as a Fermi liquid at low temperatures, indicating strong electron correlation.

  14. Development of a large-area monolithic 4x4 MPPC array for a future PET scanner employing pixelized Ce:LYSO and Pr:LuAG crystals

    We have developed a new type of large-area monolithic Multi-Pixel Photon Counter (MPPC) array consisting of a 4x4 matrix of 3x3 mm2 pixels. Each pixel comprises 3600 Geiger mode avalanche photodiodes (APDs) that achieve an average gain of 9.68x105 at 71.9 V at 0 oC with variations of only ±7.2% over 4x4 pixels. Excellent uniformity was also obtained for photon detection efficiencies (PDE) of ±6.4%, whilst dark count rates at the single photoelectron (1 p.e.) level amounted to ≅2Mcps/pixel, measured at 0 oC. As the first step toward using the device in scintillation photon detectors, we fabricated a prototype gamma-ray camera consisting of an MPPC array optically coupled with a scintillator matrix, namely a 4x4 array of 3x3 x10 mm3 crystals. Specifically, we tested the performance with Ce-doped (Lu, Y)2(SiO4)O (Ce:LYSO), Pr-doped Lu3Al5O12 (Pr:LuAG) and 'surface coated' Pr:LuAG (Pr:LuAG (WLS)) matrices whereby the emission peak of Pr:LuAG was shifted from 310 to 420 nm via a wavelength shifter (WLS). Average energy resolutions of 13.83%, 14.70% and 13.96% (FWHM) were obtained for 662 keV gamma-rays, as measured at 0 oC with Ce:LYSO, Pr:LuAG and Pr:LuAG (WLS) scintillator matrices, respectively. We confirmed that the effective PDE for Pr:LuAG (WLS) had improved by more than 30% compared to original, non-coated Pr:LuAG matrix. These results suggest that a large-area monolithic MPPC array developed here could be promising for future medical imaging, particularly in positron emission tomography (PET).

  15. A sex-specific association of common variants of neuroligin genes (NLGN3 and NLGN4X with autism spectrum disorders in a Chinese Han cohort

    Li Hui

    2011-05-01

    Full Text Available Abstract Background Synaptic genes, NLGN3 and NLGN4X, two homologous members of the neuroligin family, have been supposed as predisposition loci for autism spectrum disorders (ASDs, and defects of these two genes have been identified in a small fraction of individuals with ASDs. But no such rare variant in these two genes has as yet been adequately replicated in Chinese population and no common variant has been further investigated to be associated with ASDs. Methods 7 known ASDs-related rare variants in NLGN3 and NLGN4X genes were screened for replication of the initial findings and 12 intronic tagging single nucleotide polymorphisms (SNPs were genotyped for case-control association analysis in a total of 229 ASDs cases and 184 control individuals in a Chinese Han cohort, using matrix-assisted laser desorption/ionization time-of-flight (MALDI-TOF mass spectrometry. Results We found that a common intronic variant, SNP rs4844285 in NLGN3 gene, and a specific 3-marker haplotype XA-XG-XT (rs11795613-rs4844285-rs4844286 containing this individual SNP were associated with ASDs and showed a male bias, even after correction for multiple testing (SNP allele: P = 0.048, haplotype:P = 0.032. Simultaneously, none of these 7 known rare mutation of NLGN3 and NLGN4X genes was identified, neither in our patients with ASDs nor controls, giving further evidence that these known rare variants might be not enriched in Chinese Han cohort. Conclusion The present study provides initial evidence that a common variant in NLGN3 gene may play a role in the etiology of ASDs among affected males in Chinese Han population, and further supports the hypothesis that defect of synapse might involvement in the pathophysiology of ASDs.

  16. Hidden 12-dimensional structures in AdS5xS5 and M4xR6 supergravities

    It is shown that AdS5xS5 supergravity has hitherto unnoticed supersymmetric properties that are related to a hidden 12-dimensional structure. The totality of the AdS5xS5 supergravity Kaluza-Klein towers is given by a single superfield that describes the quantum states of a 12-dimensional supersymmetric particle. The particle has super phase space (XM,PM,Θ), with a (10,2) signature and 32 fermions. The worldline action is constructed as a generalization of the supersymmetric particle action in two-time physics. SU(2,2|4) is a linearly realized global supersymmetry of the 2T action. The action is invariant under the gauge symmetries Sp (2,R), SO(4,2), SO(6), and fermionic kappa. These gauge symmetries ensure unitarity and causality while allowing the reduction of the 12-dimensional super phase space to the correct super phase space for AdS5xS5 or M4xR6 with 16 fermions and one time, or other dually related one time spaces. One of the predictions of this formulation is that all of the SU(2,2|4) representations that describe Kaluza-Klein towers in AdS5xS5 or M4xR6 supergravity universally have vanishing eigenvalues for all the Casimir operators. This prediction has been partially verified directly in AdS5xS5 supergravity. This suggests that the supergravity spectrum supports a hidden (10,2) structure. A possible duality between AdS5xS5 and M4xR6 supergravities is also indicated. Generalizations of the approach applicable 10-dimensional super Yang-Mills theory and 11-dimensional M theory are briefly discussed

  17. An ab initio cluster study of atomic oxygen chemisorption on Ga-rich GaAs(100) (2x1) and beta(4x2) surfaces

    Mayo, Michael L.; Ray, Asok K.

    2003-01-01

    Ab initio self-consistent total energy calculations using second order Moller-Plesset perturbation theory and Hay-Wadt effective core potentials for gallium and arsenic have been used to investigate the chemisorption of atomic oxygen on the Ga-rich GaAs (100) (2 x 1) and beta(4 x 2) surfaces. Finite sized hydrogen saturated clusters with the experimental zinc-blende lattice constant of 5.654 angstroms and the energy optimized surface Ga dimer bond length of 2.758 angstroms have been used to m...

  18. Non linear excess conductivity of Bi$_2$Sr$_2$Ca$_{n-1}$Cu$_n$O$_{2n+4+x}$ (n = 1,2), thin films

    Fruchter, L.; Sfar, I; Bouquet, F.; Z. Z. Li; Raffy, H.

    2003-01-01

    The suppression of excess conductivity with electric field is studied for Bi$_2$Sr$_2$Ca$_{n-1}$Cu$_n$O$_{2n+4+x}$ ($n$ = 1, 2) thin films. A pulse-probe technique is used, which allows for an estimate of the sample temperature. The characteristic electric field for fluctuations suppression is found well below the expected value for all samples. For the $n=1$ material, a scaling of the excess conductivity with electric field and temperature is obtained, similar to the scaling under strong mag...

  19. Structure of double hafnium and sodium sulfate Hf(SO4)2x3Na2SO4xH2O

    Studied is the structure of double hafnium and sodium sulfate. The Hf(SO4)2x3Na2SO4xH2O structure determined according to the difractometric data comprises complex anions [Hf(SO4)5xH2O]6-, bound with Na+ cations and with hydrogen bonds. Eight O atoms, encicling a hafnium atom (Hf-02x10-2.33A), belong to 5 sulfate groups in the water molecule. Three sulfate groups are monodentante, and two groups are bidentate-cycling in relation to Hf

  20. Sodium-cation conductivity in the Na4-xP2-4ExO7 (E = Cr, Mo, W) systems

    Electrical conductivity of solid solutions on the basis of the sodium pyrophosphate in the Na4-xP2-4ExO7 (E = Cr, Mo, W) systems is studied. The electrolytes in the system with E = Cr have the maximum sodium-cation conductivity in the area of existence of the Na4P2O7 (1.35 x 10-1 Cm cm-1 at 700 Deg C) high temperature form. Effect of dimension and electronegativity of the E modifying elements on electrical properties of solid solutions is considered

  1. Synthesis and characterisation of molybdenum (V) and (VI) complexes of 2,6-diformyl-p-cresol-bis[4-(X-phenyl) thiosemicarbazone

    Molybdenum (V) and (VI) complexes of novel ligand 2, 6-diformyl-p-cresol bis [4-(X-phenyl) thiosemicarbazone] (where X = -H, o-CH3, m-CH3, p-CH3, p-OCH3 and p-Cl) are synthesised and characterised on the basis of elemental analyses and magnetic, IR, UV, EPR, and NMR spectral studies. The complexes have the composition [MoO2LH] and [MoOClLH]. The Schiff bases behave as dibasic tetradentate SNON donor ligands. (author)

  2. Magnetic excitations of Nd in Nd{sub 2-x}Ce{sub x}CuO{sub 4} (x=0,0.09,0.13)

    Henggeler, W.; Furrer, A. [Paul Scherrer Inst. (PSI), Villigen (Switzerland); Chattopadyay, T.; Roessli, B. [Institut Max von Laue - Paul Langevin, 75 - Paris (France); Vorderwisch, P. [Hahn-Meitner-Institut Berlin GmbH (Germany); Thalmeier, P. [MPI Dresden (Germany)

    1997-09-01

    We have studied the wave vector dependence of the magnetic excitation spectrum of Nd in Nd{sub 2-x}Ce{sub x}CuO{sub 4} (x=0,0.09,0.13) by inelastic neutron scattering experiments on single crystals. The results are analyzed with the help of model calculations which are performed in the context of the mean field random-phase approximation. This enables us to obtain direct information on the coupling constants between the rare earth ions. (author) 1 fig., 2 refs.

  3. Inelastic incoherent neutron and Raman scattering from the [K1-x(NH4)x]3H(SO4)2 mixed crystals

    Complete text of publication follows. There are known investigations of the vibrational spectrum of K2H(SO4)2 carried out by inelastic incoherent neutron scattering (IINS) (1) and Raman scattering (RS) (2). There is interest to study the influence of ammonium ions on the change of vibrational spectra of the (K1-x(NH4)x)3H(SO4)2 mixed crystals. There are presented results of vibrational spectrum study of these crystals obtained by IINS and RS in wide temperature interval for ammonium concentrations x = 0.0, 0.1 and 0.7. (author)

  4. Magnetocrystalline interactions and oxidation state determination of Mn(2−x)V(1+x)O4 (x=0, 1/3 and 1) magnetorresistive spinel family

    Oxidation states of transition metal cations in spinels-type oxides are sometimes extremely difficult to determine by conventional spectroscopic methods. One of the most complex cases occurs when there are different cations, each one with several possible oxidation states, as in the case of the magnetoresistant Mn(2−x)V(1+x)O4 (x=0, 1/3 and 1) spinel-type family. In this contribution we describe the determination of the oxidation state of manganese and vanadium in Mn(2−x)V(1+x)O4 (x=0, 1/3,1) spinel-type compounds by analyzing XANES and high-resolution Kβ X-ray fluorescence spectra. The ionic models found are Mn2+2V4+O4, Mn2+5/3V3.5+4/3O4 and Mn2+V3+2O4. Combination of the present results with previous data provided a reliable cation distribution model. For these spinels, single magnetic electron paramagnetic resonance (EPR) lines are observed at 480 K showing the interaction among the different magnetic ions. The analysis of the EPR parameters show that g-values and relative intensities are highly influenced by the concentration and the high-spin state of Mn2+. EPR broadening linewidth is explained in terms of the bottleneck effect, which is due to the presence of the fast relaxing V3+ ion instead of the weak Mn2+ (S state) coupled to the lattice. The EPR results, at high temperature, are well explained assuming the oxidation states of the magnetic ions obtained by the other spectroscopic techniques. - Graphical abstract: View of the crystallographic structure of a spinel. It shows as an example one of the models of ion distribution determined for the spinels Mn(2−x)V(1+x)O4 (x=0, 1/3,1). Display Omitted - Highlights: • Determination of oxidation state of the metallic ions in Mn(2−x)V(1+x)O4 (x=0,1/3,1) by XAS and XES techniques. • The ionic models found are Mn2+2V4+O4, Mn2+5/3V3.5+4/3O4 and Mn2+V3+O4. • EPR spectra correspond almost exclusively to a resonance of Mn2+

  5. Theoretical prediction of the structural and electronic properties of pseudocubic X3As4 (X=C, Si, Ge and Sn) compounds

    The structural and electronic properties of X3As4 (X=C, Si, Ge and Sn) compounds were investigated using density functional theory (DFT) calculations. We employed both the generalized-gradient approximation (GGA), which is based on exchange-correlation energy optimization to calculate the total energy and the Engel-Vosko (EV-GGA) formalism, which optimizes the corresponding potential for band structure calculations. The calculated lattice constant, bulk modulus and electronic band structure of pseudocubic X3As4 (X=C, Si, Ge and Sn) compounds are in good agreement with other theoretical results. The analysis shows that the hardest material is C3As4 compound with a bulk modulus B0=106.5 GPa, while Si3As4, Ge3As4 and Sn3As4 have almost the same bulk modulus ranging from 51 to 68.5 GPa. Also we have presented the results of cohesive energies and we have given a detail discussion of the bond lengths and bond angles in the pseudocubic phase of group IV arsenides. Furthermore, band structure and density of states calculations show that Si3As4, Ge3As4 and Sn3As4 exhibit a semiconductor behavior with indirect gaps while C3As4 exhibit a metallic behavior using both GGA and EV-GGA.

  6. Some new thermochromic complexes of Ni(II) of the type [R/sub x/NH/sub 4-x/]2NiCl4

    A new group of thermochromic complexes of Ni(II) of the type [R/sub x/NH/sub 4-x/]NiCl4 have been synthesized, where R is an alkyl aryl group. These complexes have been prepared from the melt of 2:1 mole ratios of R/sub x/NH/sub 3-x/HCl and anhydrous NiCl2. The complexes are brown-yellow to green-yellow at room temperature and turn blue upon heating to the thermochromic temperature (T/sub c/). Magnetic susceptibility, far-infrared spectra, and X-ray powder diffraction patterns indicate that the room-temperature phase is polymeric, containing octahedrally coordinated metal ions with bridging chlorine atoms. The hydrogen bonding from the substituted ammonium cation is important for maintaining the structure. Magnetic susceptibility and absorption and far-infrared spectra indicate that the blue phase involves discrete tetrahedral NiCl42- ions. The thermochromism is reversible and the T/sub c/ may be controlled by the degree of hydrogen bonding available from the alkyl- or arylammonium group, by the nature and the size of the R group, and by the nature of the halogen atom in the anion. Similaries with the [R/sub x/NH/sub 4-x/]2CuCl4 complexes are discussed. 4 figures, 2 tables, 42 references

  7. Dye-Sensitized Cu2 XSnS4 (X=Zn, Ni, Fe, Co, and Mn) Nanofibers for Efficient Photocatalytic Hydrogen Evolution.

    Gonce, Mehmet Kerem; Aslan, Emre; Ozel, Faruk; Hatay Patir, Imren

    2016-03-21

    The photocatalytic hydrogen evolution activities of low-cost and noble-metal-free Cu2 XSnS4 (X=Zn, Ni, Fe, Co, and Mn) nanofiber catalysts have been investigated using triethanolamine as an electron donor and eosin Y as a photosensitizer under visible-light irradiation. The rates of hydrogen evolution by Cu2 XSnS4 (X=Zn, Ni, Fe, Co, and Mn) nanofibers have been compared with each other and with that of the noble metal Pt. The hydrogen evolution rates for the nanofibers change in the order Cu2 NiSnS4 >Cu2 FeSnS4 >Cu2 CoSnS4 >Cu2 ZnSnS4 >Cu2 MnSnS4 (2028, 1870, 1926, 1420, and 389 μmol g(-1)  h(-1) , respectively). The differences between the hydrogen evolution rates of the nanofibers could be attributed to their energy levels. Moreover, Cu2 NiSnS4 , Cu2 FeSnS4 , and Cu2 CoSnS4 nanofibers show higher and more stable photocatalytic hydrogen production rates than that of the noble metal Pt under long-term irradiation with visible light. PMID:26880355

  8. Structural origin of Si-2p core-level shifts from Si(100)-c[4x2] surface: A spectral x-ray photoelectron diffraction study

    Chen, X.; Tonner, B.P. [Univ. of Wisconsin, Milwaukee, WI (United States); Denlinger, J. [Univ. of Wisconsin, Milwaukee, WI (United States)][Ernest Orlando Lawrence Berkeley National Lab., CA (United States)] [and others

    1997-04-01

    The authors have performed angle-resolved x-ray photoelectron diffraction (XPD) from a Si(100)-c(4x2) surface to study the structural origin of Si-2p core-level shifts. In the experiment, the highly resolved surface Si-2p core-level spectra were measured as a fine grid of hemisphere and photon energies, using the SpectroMicroscopy Facility {open_quotes}ultraESCA{close_quotes} instrument. By carefully decomposing the spectra into several surface peaks, the authors are able to obtain surface-atom resolved XPD patterns. Using a multiple scattering analysis, they derived a detailed atomic model for the Si(100)-c(4x2) surface. In this model, the asymmetric dimers were found tilted by 11.5 plus/minus 2.0 degrees with bond length of 2.32 plus/minus 0.05{angstrom}. By matching model XPD patterns to experiment, the authors can identify which atoms in the reconstructed surface are responsible for specific photoemission lines in the 2p spectrum.

  9. Bismuth on copper (110): analysis of the c(2x2) and p(4x1) structures by surface x-ray diffraction

    Lottermoser, L.; Buslaps, T.; Johnson, R.L.;

    1997-01-01

    Surface X-ray diffraction has been used to analyze the atomic structures of the Cu(110)-c(2 x 2)-Bi and Cu(110)-p(4 x 1)-Bi reconstructions with submonolayer coverages. A quasi-hexagonal c(2 x 2) adlayer structure is formed when half a monolayer of bismuth is deposited; the coverage corresponds to...... in excellent agreement with a model in which every fourth Cu row in the [001] direction of the topmost layer is replaced by Bi atoms to form a substitutional surface alloy. (C) 1997 Elsevier Science B.V....... 1.08 x 10(-15) atoms cm(-2). There is one Bi atom per c(2 x 2) surface unit cell, and the nearest-neighbor distance on the planar overlayer was found to be 4.43 Angstrom. In the case of the p(4 x 1) reconstruction formed at a coverage of 0.75 monolayers, both the in-plane and out-of-plane data are...

  10. Ion exchange behaviour of Zr, Hf, Nb and Pa in mixed acid solutions

    A systematic study of the adsorbabilities of zirconium, hafnium, niobium and protactinium, elements with a chemical behaviour very similar, were realised in the systems Dowex 50 - oxalic acid, Dowex 50 - oxalic acid/HCl, Dowex 1 - oxalic acid, Dowex 1 - oxalic acid/HCl, BIO-RAD AGMP1 - oxalic acid/H2SO4 and HDEHP - oxalic acid/H2SO4. These elements exhibited no significant adsorption on Dowex 50, while on the anionic exchange resins (Dowex 1 and BIO-RAD AGMP1) showed strong adsorption, particularly in oxalic acid and in mixed solutions at low concentrations of hydrochloric and sulphuric acids. This trend could be linked to the formation of anionic species of the types M(C2O4)x(n-x), MO(C2O4)x(n-(2+x)), M(C2O4H)x(n-x) and MO(C2O4H)x(n-(2+x)), or mixed complexes of the form M(Y)y(C2O4)x(n-x-y) , MO(Y)y(C2O4)x(n-(2+x+y)), where Mn+ is the metallic cation and Y the ligand. The combination of two complexing agents alter the ion exchange behaviour of the above mentioned elements. In the case of system HDEHP, we suggest a procedure to separate these elements. (author)

  11. Electron-poor SrAu xIn 4-x (0.5⩽ x⩽1.2) and SrAu xSn 4-x (1.3⩽ x⩽2.2) phases with the BaAl 4-type structure

    Tkachuk, Andriy V.; Mar, Arthur

    2007-08-01

    Solid solutions SrAu xIn 4-x (0.5⩽ x⩽1.2) and SrAu xSn 4-x (1.3⩽ x⩽2.2) have been prepared at 700 °C and their structures characterized by powder and single-crystal X-ray diffraction. They adopt the tetragonal BaAl 4-type structure (space group I4/ mmm, Z=2; SrAu 1.1(1)In 2.9(1), a=4.5841(2) Å, c=12.3725(5) Å; SrAu 1.4(1)Sn 2.6(1), a=4.6447(7) Å, c=11.403(2) Å), with Au atoms preferentially substituting into the apical over basal sites within the anionic network. The phase width inherent in these solid solutions implies that the BaAl 4-type structure can be stabilized over a range of valence electron counts (vec), 13.0-11.6 for SrAu xIn 4-x and 14.1-11.4 for SrAu xSn 4-x. They represent new examples of electron-poor BaAl 4-type compounds, which generally have a vec of 14. Band structure calculations confirm that substitution of Au, with its smaller size and fewer number of valence electrons, for In or Sn atoms enables the BaAl 4-type structure to be stabilized in the parent binaries SrIn 4 and SrSn 4, which adopt different structure types.

  12. An approach to the rationalization of radiation protection options by utility functions. The case of a 4 x 1300 MWe power plant effluent control

    This report presents a utility function approach of the optimization of radiological releases from a 4 x 1300 MWe nuclear power plant. This optimization method consists in selecting a set of appropriate effluent control options. The evaluation criteria for the different control options are the following: financial cost, ability to reduce the number of health effects and the maximum individual dose for the public, increase of occupational collective dose induced by the retention of radionuclides inside the plant. With the utility functions chosen, two different utilities can be associated to a same reduction of risk in relation with different initial levels of risk. The study shows that utility functions may be considered when the preferences of the decision-makers can be known

  13. Combustion Synthesis of Nanoparticulate LiMgxMn1-xPO4 (x=0, 0.1, 0.2) Carbon Composites

    Doeff, Marca M; Chen, Jiajun; Conry, Thomas E.; Wang, Ruigang; Wilcox, James; Aumentado, Albert

    2009-12-14

    A combustion synthesis technique was used to prepare nanoparticulate LiMgxMn1-xPO4 (x=0, 0.1,0.2)/carbon composites. Powders consisted of carbon-coated particles about 30 nm in diameter, which were partly agglomerated into larger secondary particles. The utilization of the active materials in lithium cells depended most strongly upon the post-treatment and the Mg content, and was not influenced by the amount of carbon. Best results were achieved with a hydrothermally treated LiMg0.2Mn0.8PO4/C composite, which exhibited close to 50percent utilization of the theoretical capacity at a C/2 discharge rate.

  14. RTNS-II: experience at 14-MeV source strengths between 1 x 1013 and 4 x 1013 n/s

    The design concepts, operational experience, and modifications of the two RTNS-II (Rotating Target Neutron Source-II) 14 MeV neutron sources are reviewed. The original design called for operation at a peak neutron source strength of 4 x 1013 n/cm2s. The facility was to operate at high plant factor and at an acceptable cost in both dose delivered to operating staff and releases to the environment. The possibilities of higher source strengths are discussed in light of the operating experience to date and of new technologies that may be applied to the problems of high flux generators of this type. Changes in ancillary equipment that would provide more efficient or safe operation are also indicated

  15. Numerical simulations of void fractions in air-water tests with a 4 x 4 rod bundle under stagnant water conditions

    After termination of natural circulation during hypothetical accidents in light water reactors, vapor generated by decay heat forms two-phase flow in stagnant coolant liquid and rises in a reactor core. In these conditions, void fractions in the reactor core affect the two-phase mixture level and cooling of fuel rods. In this study, numerical simulations were carried out for a 4 x 4 rod bundle which was a mock-up of the PWR core by using the computational fluid dynamics (CFD) software, FLUENT 6.3.26. Simulated void fractions showed a similar trend to air-water data but were about 0.10 higher than measured void fractions at large air volumetric fluxes. Over-prediction of void fractions might be due to severe flooding at the upper end of the bundle. (author)

  16. Study of the crystal structure of double ammonium hafnium sulfate of the (NH4)4Hf(SO4)4x4H2O composition

    Two new double compounds of (NH4)2Hf(SO4)3x2H2O and (NH4)4Hf(SO4)4x4H2O have been studied. The second compound which forms needle transparent crystals of monoclinic singony, has been studied by the X-ray analysis. The unit cell parametres are as follows: a = 18.12(3), b = 14.89(3), c = 7.25(3) A, γ = 95.5 deg (5), spatial group P2/b, N=4. The first structure may be described as an islet structure. Besides basic valent bonds, it contains numerous intermolecular contacts and hydrogen bonds formed by water molecules and ammonium ions

  17. Structure of double cerium and potassium sulfate, 2K2SO4xCe(SO4)2x2H2O

    A diffractometric investigation of 2K2SO4xCe(SO4)2x2H2O structure is carried out. The refined compound parameters are equal to: a=12.407(2), b=11.160(2), c=13.539(2) A, β=111.63(1) deg, V=1742.6(8) A3, Z=4, dsub(calcd)=2.747(1) g/cm3, space group P21/c. Atom coordinates, interatomic distances and valent angles are presented. A conclusion is made that the compound of 2K2SO4cxCe(SO4)2x2H2O brutto-composition has K8[Ce2(SO4)8]4H2O structural formula and contains dimeric anions [(SO4)3Ce(μ-SO4)2xCe(SO4)3]8-

  18. Use the nuclear code MCNP4X in the study of the behavior of nuclear probe in soils with variation of Mg, Ca, Fe

    The aim of this work is to evaluate the behavior of the variation the elements: Mg, Ca, Fe in the soils composition on a nuclear probe to measure the density of porous materials nondestructive in testing based on coherent Compton Effect, the effect Rayleigh. To study the effect of composition in soil was used nuclear code MCNP4X where was simulated two sources, a source 14mCi americium-241 and other source 4mCi cesium-137, lead shielding and volume scintillator. To avoid problems with geometries were simulated spheres with 1.00 meters of diameter filled with soil to be evaluated. Data analysis allowed establishing correction parameters for nuclear probe. (author)

  19. Synthesis, characterization and magnetic properties of lightly doped La2-xSr xCuO4 (x = 0.04) nanoparticles

    Lightly doped La2-xSr xCuO4 (x = 0.04) nanoparticles with different particle sizes have been successfully prepared by a sol-gel method and characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), infrared transmission (IR) spectra and superconducting quantum interference device (SQUID) magnetometer. All samples are single phase and have an orthorhombic unit cell. As the particle size reduces, it is found that the IR band at around 685 cm-1 corresponding to the in-plane Cu-O asymmetrical stretching mode shifts to higher frequency and the magnetization exhibits a large enhancement at low temperature. The magnetic susceptibility of all samples follows a modulated Curie law between ∼20 K and ∼100 K and the Curie constant displays a strong dependence on the particle size. It is suggested that as the particle size decreases surface effects should play an important role in the magnetic properties of the nanoparticles

  20. Performance evaluation of a PET detector consisting of an LYSO array coupled to a 4 x 4 array of large-size GAPD for MR compatible imaging

    Hong, Key Jo; Choi, Yong; Kang, Jihoon; Hu, Wei; Jung, Jin Ho; Min, Byung Jun [Department of Electronic Engineering, Sogang University, 1 Shinsu-Dong, Mapo-Gu, Seoul 121-742 (Korea, Republic of); Chung, Yong Hyun [Department of Radiological Science, Yonsei University, College of Health Science, 234 Meaji, Heungup Wonju, Kangwon-Do, 220-710 (Korea, Republic of); Jackson, Carl, E-mail: ychoi@sogang.ac.kr [SensL, Blackrock, Cork (Ireland)

    2011-05-01

    We examined a PET detector consisting of an LYSO array coupled to a 4 x 4 array of large-size Geiger-mode avalanche photodiode (GAPD). The GAPD coupled to 3 mm x 3 mm x 20 mm LYSO pixel crystal has been investigated for possible use as an MR-compatible PET photosensor. Primary characteristics of a PET detector, such as energy resolution and coincidence timing resolution were measured. Gain variation, count uniformity, and count estimation error of 4 x 4 array of LYSO-GAPD were measured to evaluate the performance parameters relevant for PET imaging. The energy resolution and coincidence timing resolution with 511 keV gamma rays were 18.5 {+-} 0.7% and 1.6 ns, respectively. The gain variation, count uniformity for all 16 channels were 1.3:1 and 1.3:1, respectively. The count estimation error between adjacent channels measured with an LYSO connected to a GAPD pixel was negligible (0.24 {+-} 0.04%). Long-term stability results show that there was no significant change in the photopeak position, energy resolution and count rate for 20 days. Cable lengths up to 300 cm, used between the GAPD and preamplifier, did not affect photopeak position and energy resolution. The performance of the LYSO-GAPD detector inside the MRI exhibited no significant change compared to that measured outside the MRI. The MR images acquired with and without the operating LYSO-GAPD detector located on top of the RF coil showed no considerable degradation in image quality. These results demonstrate the feasibility of using the LYSO-GAPD detector as PET photosensors, which could be used for MR compatible PET development.

  1. Optical phonons in CdGa{sub 2}S{sub 4x}Se{sub 4(1-x)} alloys

    Kerimova, T. G., E-mail: taira-kerimova@mail.ru; Abdullaev, N. A.; Mamedova, I. A.; Badalova, Z. I.; Guliev, R. A. [National Academy of Sciences of Azerbaijan, Institute of Physics (Azerbaijan); Paucar, R.; Wakita, K. [Chiba Institute of Technology (Japan); Mamedov, N. T. [National Academy of Sciences of Azerbaijan, Institute of Physics (Azerbaijan)

    2013-06-15

    The Raman spectra of CdGa{sub 2}S{sub 4x}Se{sub 4(1-x)} alloys (x = 0.1, 0.2, Horizontal-Ellipsis 0.9) are studied. Both the singlemode and double-mode behavior of optical phonons are observed in CdGa{sub 2}S{sub 4x}Se{sub 4(1-x)} alloys. The observed optical mode at 138 cm{sup -1} is independent of the composition. It seems likely that this mode is the 'breathing mode' and is caused by atomic motion in the anion sublattice relative to vacancies. It is shown that the high-frequency modes of symmetry B{sub 1}(LO, TO) and B{sub 2}(LO, TO) are caused by the in-phase motion of atoms in the anion sublattice along the tetragonal axis c relative to trivalent Ga atoms. The doubly degenerate symmetry modes E{sub 1}(LO, TO) and E{sub 2}(LO, TO) are caused by the in-phase motion of atoms in the anion sublattice relative to trivalent Ga atoms of the cation sublattice in the xy plane (dipole 2Ga-4C), where C is S, Se. The optical symmetry modes B{sub 3}(LO, TO) and B{sub 4}(LO, TO) are associated with the motion of atoms in the anion sublattice relative to Cd atoms along the tetragonal axis c. The doubly degenerate modes E{sub 3}(LO, TO) and E{sub 4}(LO, TO) are associated with the motion of atoms in the anion sublattice relative to Cd atoms (dipole Cd-4C). The low-frequency modes B{sub 5}(LO, TO) and E{sub 5}(LO, TO) are the analogs of acoustic phonons at the edge of the Brillouin zone of sphalerite.

  2. Magnetocrystalline interactions and oxidation state determination of Mn(2-x)V(1+x)O4 (x=0, 1/3 and 1) magnetorresistive spinel family

    Pomiro, F.; Ceppi, S.; De Paoli, J. M.; Sánchez, R. D.; Mesquita, A.; Tirao, G.; Pannunzio Miner, E. V.

    2013-09-01

    Oxidation states of transition metal cations in spinels-type oxides are sometimes extremely difficult to determine by conventional spectroscopic methods. One of the most complex cases occurs when there are different cations, each one with several possible oxidation states, as in the case of the magnetoresistant Mn(2-x)V(1+x)O4 (x=0, 1/3 and 1) spinel-type family. In this contribution we describe the determination of the oxidation state of manganese and vanadium in Mn(2-x)V(1+x)O4 (x=0, 1/3,1) spinel-type compounds by analyzing XANES and high-resolution Kβ X-ray fluorescence spectra. The ionic models found are Mn2+2V4+O4, Mn2+5/3V3.5+4/3O4 and Mn2+V3+2O4. Combination of the present results with previous data provided a reliable cation distribution model. For these spinels, single magnetic electron paramagnetic resonance (EPR) lines are observed at 480 K showing the interaction among the different magnetic ions. The analysis of the EPR parameters show that g-values and relative intensities are highly influenced by the concentration and the high-spin state of Mn2+. EPR broadening linewidth is explained in terms of the bottleneck effect, which is due to the presence of the fast relaxing V3+ ion instead of the weak Mn2+ (S state) coupled to the lattice. The EPR results, at high temperature, are well explained assuming the oxidation states of the magnetic ions obtained by the other spectroscopic techniques.

  3. Finite-size corrections in the SU(2)xSU(2) sector of type IIA string theory on AdS4xCP3

    We consider finite-size corrections in the SU(2)xSU(2) sector of type IIA string theory on AdS4xCP3, which is the string dual of the recently constructed N=6 superconformal Chern-Simons theory of Aharony, Bergman, Jafferis and Maldacena (ABJM theory). The string states we consider are in the RxS2xS2 subspace of AdS4xCP3 with an angular momentum J on CP3 being large. We compute the finite-size corrections using two different methods, one is to consider curvature corrections to the Penrose limit giving an expansion in 1/J, the other by considering a low energy expansion in λ'=λ/J2 of the string theory sigma-model, λ being the 't Hooft coupling of the dual ABJM theory. For both methods there are interesting issues to deal with. In the near-pp-wave method there is a 1/√(J) interaction term for which we use zeta-function regularization in order to compute the 1/J correction to the energy. For the low energy sigma-model expansion we have to take into account a non-trivial coupling to a non-dynamical transverse direction. We find agreement between the two methods. At order λ' and λ'2, for small λ', our results are analogous to the ones for the SU(2) sector in type IIB string theory on AdS5xS5. Instead at order λ'3 there are interactions between the two two-spheres. We compare our results with the recently proposed all-loop Bethe ansatz of Gromov and Vieira and find agreement

  4. Five Layers Aurivillius Phases Pb2-xBi4+xTi5-xMnxO18: Synthesis, Structure, Relaxor Ferroelectric and Magnetic Properties

    Zulhadjri

    2011-07-01

    Full Text Available Synthesis of five layers Aurivillius phases, Pb2-xBi4+xTi5-xMnxO18 (0 £ x £ 1 were carried out by molten salts method using eutectic mixture of Na2SO4/K2SO4 salts (1:1 molar ratio as the flux. The samples were characterized by X-ray diffraction powder and refined by Le Bail technique. The refinement results revealed that the samples with composition x = 0, 0.2, 0.4, and 0.6 formed five layers Aurivillius with the space group B2cb; however, the samples with x = 0.4 and 0.6 contained impurity as BiMnO3 and the additional phase of four layers Aurivillius (PbBi4Ti4O15 was also observed for x = 0.6. The samples with x = 0.8 and 1 resulted in two phases: four layers Aurivillius and BiMnO3. The dielectric properties of the Pb2-xBi4+xTi5-xMnxO18 show broad peaks with anomaly (Tm at temperature 295 °C, 295 °C, 304 °C, and 343 °C at frequency 2 MHz for x = 0, 0.2, 0.4, and 0.6, respectively. The Tm of these samples is shift to the left with decreasing frequency as indication of relaxor ferroelectric behavior. The samples with x = 0.8 and 1 show anomaly at 514 °C and 551 °C which correspond to the transition phase of four layers Aurivillius. Magnetic properties for all samples containing Mn are paramagnetic.

  5. Amino acids

    Amino acids are organic compounds that combine to form proteins . Amino acids and proteins are the building blocks of life. When proteins are digested or broken down, amino acids are left. The human body uses amino acids ...

  6. Non-stoichiometric cobalt ferrite, CoxFe3−xO4 (x=1.0 to 2.0): Structural, magnetic and magnetoelastic properties

    This work discusses the changes in the structural, magnetic and magnetoelastic properties of CoxFe3−xO4 (x=1.0 to 2.0) due to variations in cation concentration and the presence of a secondary Co1−yFeyO phase. Non-stoichiometric cobalt ferrite samples used in this study were prepared via the ceramic method. Samples with x>1 possess two phases; a secondary rock salt Co1−yFeyO phase and a spinel cobalt ferrite phase with varying cation concentration. The sample x=1 has only the spinel phase. Increase in Co concentration resulted in a decrease in magnetization but an increase in coercivity. Magnetostrictive properties and magnetocrystalline anisotropy were also affected by deviation from stoichiometric composition. Results are discussed on the basis of the coexistence of Co3+, Co2+ and Fe3+ in the spinel lattice of the samples and the influence of the secondary Co1−yFeyO phase on the overall properties

  7. Measurement of environmental natural radiation level using 4 channel pulse height discriminator with Φ 4 x 4 NaI(Tl) detector

    A method used to measure and distinguish between different components of environmental natural radiation covering cosmic rays using 4 channel pulse height discriminator with Φ 4 x 4 in NaI(Tl) detector is dealt with. The discriminating thresholds for 4 channels called Disr, Ch1, Ch2 and Ch3 were so designed that the gamma ray energy to be recorded by them can fall within 0.58 MeV-∞ for gamma rays from 40K, U, Th and cosmic rays, within 2.0-4.2 MeV for 2.2 MeV gamma ray of U series 214Bi, 2.61 MeV gamma ray of Th series 208Tl and a small amount of low energy cosmic rays, within 4.2 MeV -∞ for all cosmic rays, excluding a small amount of low energy cosmic rays and within 12.5 MeV -∞ for higher energy cosmic rays, respectively. Using such method, measurements were carried out in the first floor and the ground steel chamber of Low Background Radioactivity Laboratory of China Institute for Radiation Protection. The counts measured in airplanes of Guangzhou-Taiyuan and Beijing-Osaka are also presented

  8. Domain and surface structures of sodium tungsten bronzes, Na/sub x/WO/sub 3/ (0. 4 < x < 1). [157 references

    Atoji, M.

    1978-09-01

    The domain and surface structures of metallic sodium tungsten bronzes, Na/sub x/WO/sub 3/, 0.4 < x < 1, were studied using optical microscopy, supplemented by chemical methods, photoelectron spectroscopy, electron microscopy, etc. The birefringent, multidomain structure of the bronze is exhibited by a sodium-deficient, epitaxial surface film and hence is not, as reported elsewhere, a bulk property. The film can be synthesized by anodic electrolysis in alkaline solution and can exist only epitaxially with the substrate. It is chemically inert, translucent, and often laminated to a multilayered film. The film domain is hypersensitive to lateral stress and to thermal change, and appears to be modulated by minute structural changes of the substrate. This epitaxial modulation of the film is strikingly large at the phase transitions of the substrate induced by slightly different tiltings of the oxygen octahedra. The domain-wall movement is often slow enough to be visible, and that by thermal effect is occasionally accompanied by an audible, high-pitched, snapping sound.

  9. The phase situation and ferroelectric properties in the mixed crystals [4-NH 2PyH][SbCl 4(1- x) Br 4 x

    Wojtaś, M.; Jakubas, R.; Zaleski, J.; Bator, G.; Baran, J.

    2008-09-01

    The group of mixed crystals of general formula: [4-APyH][SbCl 4(1- x) Br 4 x] with x ranging from 0 to 1 was studied by means of differential scanning calorimetry, dilatometry and dielectric spectroscopy. The ferroelectric properties are preserved for mixed crystals with replacement fraction, x, less than 0.30. Moreover, such a substitution of the chlorine atoms by the bromine ones significantly lowers the temperature of the structural phase transition shifting it from 240 K for pure [4-APyH][SbCl 4] to about 185 K for the mixed crystals richer in bromine. The dielectric relaxation process exhibited by the mixed crystal with x = 0.90 in the radio-frequency region was analyzed and the activation energy was estimated ( Ea = 18 kJ/mol). Additional measurements of single crystals X-ray diffraction and powder IR and Raman spectroscopy were performed. On the basis of the experimental results the phase diagram for mixed crystals has been proposed.

  10. Crystal structure and spontaneous polarization of Bi4-xNdxTi3O12 studied by using neutron powder diffraction data

    Crystal structural parameters of Bi4-xNdxTi3O12 (BNT, x = 0.25, 0.5, 0.75 and 1.0) were determined by means of neutron powder diffraction and Rietveld analysis based on the monoclinic space group of B1a1. The a-axis has been found to shrink monotonically from 5.4475(8) to 5.4100(1) A with x increasing from 0 to 0.75. The orthorhombicity defined as 2(a-b)/(a+b) decreased with increasing x because the b-axis lattice parameter remained almost constant. The c-axis increases monotonically up to x = 0.75. The spontaneous polarization, which is oriented along the a-axis (Ps//a), decreased from 35.4 to 28.3, 24.8 and 22.2 μC cm-2 with x increasing from 0 to 0.25, 0.5 and 0.75, respectively as calculated by using the refined structural parameters. Thus, the substitution of Nd for Bi has been found to cause a considerable structural relaxation. Bi3Nd1Ti3O12 showed a considerably small a-lattice parameter of 5.4004 (1) A and a very small Ps value of only 7.5 μC cm-2 indicating that its structure is orthorhombic or close to tetragonal

  11. Clumpy photon-dominated regions in Carina. I. [CI] and mid-J CO lines in two 4'x4' fields

    Kramer, C; Roellig, M; Sun, K; Yonekura, Y; Aravena, M; Bensch, F; Benz, A; Bertoldi, F; Bronfman, L; Fujishita, M; Fukui, Y; Graf, U U; Hitschfeld, M; Honingh, N; Ito, S; Jakob, H; Jacobs, K; Klein, U; Koo, B -C; May, J; Miller, M; Miyamoto, Y; Mizuno, N; Onishi, T; Park, Y -S; Pineda, J L; Rabanus, D; Sasago, H; Schieder, R; Simon, R; Stutzki, J; Volgenau, N; Yamamoto, H

    2007-01-01

    The Carina region is an excellent astrophysical laboratory for studying the feedback mechanisms of newly born, very massive stars within their natal giant molecular clouds (GMCs) at only 2.35 kpc distance. We use a clumpy PDR model to analyse the observed intensities of atomic carbon and CO and to derive the excitation conditions of the gas. The NANTEN2-4m submillimeter telescope was used to map the [CI] 3P1-3P0, 3P2-3P1 and CO 4-3, 7-6 lines in two 4'x4' regions of Carina where molecular material interfaces with radiation from the massive star clusters. One region is the northern molecular cloud near the compact OB cluster Tr14, and the second region is in the molecular cloud south of etaCar and Tr16. These data were combined with 13CO SEST spectra, HIRES/IRAS 60um and 100um maps of the FIR continuum, and maps of 8um IRAC/Spitzer and MSX emission. We used the HIRES far-infrared dust data to create a map of the FUV field heating the gas. The northern region shows an FUV field of a few 1000 in Draine units whi...

  12. Magnetic properties of (Fe1−xNix)72B20Si4Nb4 (x=0.0–0.5) bulk metallic glasses

    The effects of partial substitution of Fe by Ni in (Fe1−xNix)72B20Si4Nb4 (x=0.0, 0.1, 0.2, 0.3, 0.4, and 0.5) bulk metallic glasses (BMGs) on their magnetic properties were studied. It is found that the saturation polarization decreases from 1.15 T to 0.69 T with increasing Ni content from x=0.0 to x=0.5; the Curie temperature reaches its maximum of 598 K for composition x=0.1, and is then followed by a quick decrease with higher Ni content. Moreover, the random anisotropy and mean field theory were developed to investigate the magnetic properties of these BMGs, and the variations of saturation polarization and Curie temperature were well explained by calculating the magnetic exchange stiffness constant A and the nearest neighbor transition-metal-pair exchange interactions J by using the model. - Highlights: ► Fully glassy rods of (Fe1−xNix)72B20Si4Nb4 BMGs were produced up to 1.5 mm in diameter. ► Variations in saturation polarization and Curie temperature of (Fe1−xNix)72B20Si4Nb4 BMGs were investigated. ► Random anisotropy and mean field theory were developed to explain the variation of magnetic properties

  13. Superconductivity in the orthorhombic phase of thermoelectric CsPbxBi4-xTe6 with 0.3≤x≤1.0

    Zhang, R. X.; Yang, H. X.; Tian, H. F.; Chen, G. F.; Wu, S. L.; Wei, L. L.; Li, J. Q.

    2015-12-01

    Experimental measurements clearly reveal the presence of bulk superconductivity in the CsPbxBi4-xTe6 (0.3≤x≤1.0) materials, i.e. the first member of the thermoelectric series of Cs[PbmBi3Te5+m], these materials have the layered orthorhombic structure containing infinite anionic [PbBi3Te6]- slabs separated with Cs+ cations. Temperature dependences of electrical resistivity, magnetic susceptibility, and specific heat have consistently demonstrated that the superconducting transition in Cs0.96Pb0.25Bi3.75Te6.04 occurs at Tc=3.1 K, with a superconducting volume fraction close to 100% at 1.8 K. Structural study using aberration-corrected STEM/TEM reveals a rich variety of microstructural phenomena in correlation with the Pb-ordering and chemical inhomogeneity. The superconducting material Cs0.96Pb0.25Bi3.75Te6.04 with the highest Tc shows a clear ordered structure with a modulation wave vector of q≈a*/2+c*/1.35 on the a-c plane. Our study evidently demonstrates that superconductivity deriving upon doping of narrow-gap semiconductor is a viable approach for exploration of novel superconductors.

  14. Theoretical estimates of the anapole magnetizabilities of C4H4X2 cyclic molecules for X=O, S, Se, and Te

    Calculations have been carried out for C4H4X2 cyclic molecules, with X=O, S, Se, and Te, characterized by the presence of magnetic-field induced toroidal electron currents and associated orbital anapole moments. The orbital anapole induced by a static nonuniform magnetic field B, with uniform curl C=∇×B, is rationalized via a second-rank anapole magnetizability tensor aαβ, defined as minus the second derivative of the second-order interaction energy with respect to the components Cα and Bβ. The average anapole magnetizability a¯ equals −χ¯, the pseudoscalar obtained by spatial averaging of the dipole-quadrupole magnetizability χα,βγ. It has different sign for D and L enantiomeric systems and can therefore be used for chiral discrimination. Therefore, in an isotropic chiral medium, a homogeneous magnetic field induces an electronic anapole Aα, having the same magnitude, but opposite sign, for two enantiomorphs

  15. Theoretical estimates of the anapole magnetizabilities of C4H4X2 cyclic molecules for X=O, S, Se, and Te

    Pagola, G. I.; Ferraro, M. B.; Provasi, P. F.; Pelloni, S.; Lazzeretti, P.

    2014-09-01

    Calculations have been carried out for C4H4X2 cyclic molecules, with X=O, S, Se, and Te, characterized by the presence of magnetic-field induced toroidal electron currents and associated orbital anapole moments. The orbital anapole induced by a static nonuniform magnetic field B, with uniform curl {{C}}=nabla × {{B}}, is rationalized via a second-rank anapole magnetizability tensor aαβ, defined as minus the second derivative of the second-order interaction energy with respect to the components Cα and Bβ. The average anapole magnetizability overline{a} equals -overline{χ }, the pseudoscalar obtained by spatial averaging of the dipole-quadrupole magnetizability χα,βγ. It has different sign for D and L enantiomeric systems and can therefore be used for chiral discrimination. Therefore, in an isotropic chiral medium, a homogeneous magnetic field induces an electronic anapole A_{α }, having the same magnitude, but opposite sign, for two enantiomorphs.

  16. Li EXCESS Li4+xTi5-xO12-δ/C COMPOSITE USING SPRAY-DRYING METHOD AND ITS ELECTRODE PROPERTIES

    Yoshikawa, Daisuke; Suzuki, Norio; Kadoma, Yoshihiro; Ui, Koichi; Kumagai, Naoaki

    2012-03-01

    We have prepared a lithium excess carbon composite material, Li4+xTi5-xO12-δ/C (LTO/C), using various amounts of sucrose as a carbon source by the spray-drying method. The prepared materials were characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), and elemental analysis. The prepared material had the Li4Ti5O12 phase including 3.9-18.4 wt.% carbon. Transmission electron microscopy images and the selected area diffraction (SAD) pattern showed that the prepared materials consisted of a carbon nanonetwork in the LTO/C composite. The charge-discharge cycling tests were carried out using the R2032 coin-type cell under the following conditions; 1.2-3.0 V, 0.1 C-10 C (1 C = 175 mA g-1), 25°C. Based on the electrochemical results, the electrode performance of the prepared material was improved with increasing amounts of residual carbon, in particular, LTO/C including 6.2 wt.% residual carbon exhibited the best electrode performance of 156 mAh g-1 at 1 C during 50 cyclings when compared to the other materials.

  17. Synthesis and properties of superconducting HgBa2CuO4+x from a single-step low-temperature solid state reaction

    A novel technique based on a low-temperature single-step solid state reaction of stoichiometric quantities of HgO and Ba2CuO3 to produce superconducting HgBa2CuO4+x samples has been developed. The 'as-prepared' polycrystalline Hg-1201 samples had a Tc of 95 K, as obtained by the diamagnetic onset and resistivity measurements. The crystal symmetry was tetragonal with lattice parameters a = 3.876(1) AA, and c = 9.509(4) AA in agreement with literature data. Sample morphology consists of grains (average dimension 30 μ m) larger than in previously published works and of a needle-like structure embedding the whole sample. These results were highly reproducible over several batches. The resistive transition in magnetic field up to 8 T and a set of magnetic measurements is presented. From these measurements we obtain information about the irreversibility line, the critical current field dependence and the presence of weak links. (author)

  18. Calculation of size specific dose estimates (SSDE) value at cylindrical phantom from CBCT Varian OBI v1.4 X-ray tube EGSnrc Monte Carlo simulation based

    Nasir, M.; Pratama, D.; Anam, C.; Haryanto, F.

    2016-03-01

    The aim of this research was to calculate Size Specific Dose Estimates (SSDE) generated by the varian OBI CBCT v1.4 X-ray tube working at 100 kV using EGSnrc Monte Carlo simulations. The EGSnrc Monte Carlo code used in this simulation was divided into two parts. Phase space file data resulted by the first part simulation became an input to the second part. This research was performed with varying phantom diameters of 5 to 35 cm and varying phantom lengths of 10 to 25 cm. Dose distribution data were used to calculate SSDE values using trapezoidal rule (trapz) function in a Matlab program. SSDE obtained from this calculation was compared to that in AAPM report and experimental data. It was obtained that the normalization of SSDE value for each phantom diameter was between 1.00 and 3.19. The normalization of SSDE value for each phantom length was between 0.96 and 1.07. The statistical error in this simulation was 4.98% for varying phantom diameters and 5.20% for varying phantom lengths. This study demonstrated the accuracy of the Monte Carlo technique in simulating the dose calculation. In the future, the influence of cylindrical phantom material to SSDE would be studied.

  19. Preparation and characterization of a new tetrahedral oxynitride phase Cd{sub 2-x}GeO{sub 4-x-3y}N{sub 2y}

    Picard, C.L. dit; Merdrignac, O.; Guyader, J.; Laurent, Y. [Universite de Rennes (France)

    1995-11-01

    A new oxynitride phase, Cd{sub 2-x}GeO{sub 4-x-3y}N{sub 2y}, with 0.9 {le} x {le} 1.5 and 0.3 {le} y {le} 0.7 has been prepared by reaction of gaseous ammonia on a {open_quotes}Cd-Ge-O{close_quotes} amorphous phase. Its composition depends on the synthesis conditions and more particularly on the starting ratio Cd/Ge. The amorphous precursor is obtained by coprecipitation of cadmium and germanium oxides and gives after heating in air the crystallized double oxide Cd{sub 2}GeO{sub 4} with or without the CdO oxide phase, depending on the initial Cd/Ge ratio. The oxynitrides obtained after nitridation have been characterized by chemical analysis and X-ray diffraction. They present a tetrahedral structure derived from the wurtzite type with orthorhombic symmetry. The lattice parameters are 5.60 {le} a {le} 5.75 {Angstrom}, 6.80 {le} b {le} 6.85 {Angstrom}, and c {approx} 5.39 {Angstrom}. Electrical properties have been investigated and reveal that Cd{sub x}GeO{sub y}N{sub z}-based thick films can be used as gas sensors.

  20. Ammonium dynamics in the disordered α-phase of K1-x(NH4)xY (Y = Cl, Br, I). A neutron scattering study

    The effect of temperature and concentration on the lattice parameters and amplitude-weighted phonon density of states in mixed salts of ammonium-potassium halides is investigated by neutron powder diffraction and incoherent inelastic neutron scattering. In the disordered α-phase (NaCl type) ammonium ions exhibit a fast stochastic reorientation at phonon frequency rates down to ca. 80 K. At 10 K, the incoherent inelastic neutron scattering spectra display four distinct ammonium excitations: two (resonant) modes below and two (localized) above the Debye cut-off energy of potassium halides. High-frequency localized modes correspond to translational and librational vibrations of NH4 ions. These modes are typical for the ordered phases of ammonium halides. The effect of ammonium concentration on localized and resonant modes is studied for the K1-x(NH4)xI mixed salts. The harmonic excitations of ammonium in a hypothetical low-temperature α-phase of NH4I are approximated to ca. 30, 95, 155 and 250 cm-1. In a real low-temperature ordered γ-phase of NH4I, translational ammonium vibrations are observed at ca. 140-160 cm-1 and librational vibrations at ca.300 cm-1

  1. Comparison of boiling curves at reflood test and post-CHF test with 4 x 4 bundle test section under high-pressure

    Boiling curves obtained at reflood tests and post-CHF tests were investigated. Experiments were performed with 4 x 4-rod-bundle test section under high-pressure (15.5 MPa) and mass flux of 33-1100 kg/m2s. Post-CHF tests are performed at constant mass flux with stepwise power increase. Data are obtained under steady condition. Reflood tests are performed at constant power with stepwise increase in mass flux. Data are obtained under transient condition. Reflood tests indicated two types of rewetting temperature. One was observed under low power, where rewetting temperature was almost constant value independently of power. The other was observed under high power, where rewetting temperature increased with power. These suggest there exist two types of rewetting temperatures and hence two types of boiling curves at reflood tests dependently on power. Post-CHF tests indicated heat flux was lower during boiling transition than during rewetting. Similarity of boiling curves between reflood and post-CHF tests was observed under low mass flux. In this case, boiling curves at reflood tests became closer with higher power to that of post-CHF tests. However at high mass flux, rewetting temperature at post-CHF tests was much higher than that at reflood tests. This difference is considered due to higher heat transfer coefficient by lower void fraction at post-CHF tests. (author)

  2. Influence of Concentration and Temperature on Tunneling and Rotational Dynamics of Ammonium in $Rb_{1-x}(NH_{4})_{x}$ Mixed Crystals

    Natkaniec, I; Martínez-Sarrion, M L; Mestres, L; Herraiz, M; Smirnov, L S; Shuvalov, L A

    2001-01-01

    The Rb_{1-x}(NH_{4})_{x} mixed crystals are studied by inelastic incoherent neutron scattering using time-of-flight spectrometers in the concentration region of the x-T phase diagram 0.01\\lq x \\lq 0.66 at 5\\lq T \\lq 150 K, where dynamic and static orientational disorder phases are generally found. It is shown that at 5 K rotational tunneling levels for ammonium concentrations x=0.01,0.02 and 0.06 are similar. Additional tunneling levels are observed for x=0.16 which can be explained as the result of T-states splitting for annount of NH_{4}-NH_{4} interaction. Tunneling levels are not observed for 0.40 as the result of forming orientational glass state. The elastic incoherent structure factors for concentrations 0.01\\lq x \\lq 0.16 (dynamic orientational disordered \\alpha-phase), x=0.40 (orientational glass state) and 0.50\\lq x \\lq 0.66 (orientational ordered state) have different temperature dependences.

  3. Exchange bias phenomena in Ni{sub 2−x}Mn{sub 1.4+x}Ga{sub 0.6}

    Khan, Mahmud, E-mail: khanm2@miamioh.edu; Chapai, Ramakanta

    2015-10-25

    We have performed an experimental investigation on the magnetic properties of Ni{sub 2−x}Mn{sub 1.4+x}Ga{sub 0.6} alloys that exhibit the L1{sub 0} martensitic structure at room temperature. Exchange bias effects under both zero field cooled and field cooled conditions have been observed in the alloys. The ac susceptibility data show frequency dependence with the low temperature magnetic anomaly shifting to higher temperatures with increasing frequency, suggesting towards a spin glass nature of the ground state. The experimental results are explained in terms of the competing ferromagnetic and antiferromagnetic interactions due to the Mn atoms occupying multiple crystalline sites. - Highlights: • We have investigated the magnetic properties of Ni{sub 2−x}Mn{sub 1.4−x}Ga{sub 0.6} alloys. • The exchange bias properties of the alloys have been explored. • Competing ferromagnetic and antiferromagnetic interactions exist in the alloys. • The competing interactions results in interesting magnetic properties. • AC susceptibility data shows the presence spin glass type magnetic state.

  4. Structural, optical and electrical properties of Cu2FeSnX4 (X = S, Se) thin films prepared by chemical spray pyrolysis

    Highlights: • CFTS(Se) thin films have been synthesized by low-cost spray-based deposition. • The fabricated films were found to be of stannite structure and p-type conductivity. • Band gaps of CFTS and CFTSe thin films are 1.37 and 1.11 eV, respectively. - Abstract: We report on fabrication of polycrystalline Cu2FeSnX4 (X = S, Se) thin films by chemical spray pyrolysis subsequent with post-sulfurization and selenization. The post-annealing of as-sprayed Cu2FeSnS4 (CFTS) films in sulfur and selenium ambient demonstrated drastically improved surface texture as well as crystallinity. The crystal lattice parameters calculated from X-ray diffraction patterns for post-annealed films were found to be consistent with stannite structure. The fabricated Cu2FeSnS4 (CFTS) and Cu2FeSnSe4 (CFTSe) films showed p-type conductivity with carrier concentration in the range of 1021 cm−3 and mobility ∼1–5 cm2 V−1 s−1. The band gap energies of post-sulfurized CFTS and post-selenized CFTSe films were estimated to be ∼1.37 eV and ∼1.11 eV with an error of ±0.02 eV by UV–Vis absorption, respectively, which are promising for photovoltaic application

  5. Adsorption kinetic regime of cocrystallization. The system ZnC/sub 2/O/sub 4/x2H/sub 2/O-/sup 54/MnC/sub 2/O/sub 4/x2H/sub 2/0. 1. Adsorption and surface cocrystallization of /sup 54/Mn

    Melikhov, I.V.; Berdonosova, D.G.; Pencheva, Zh.

    1984-01-01

    The ZnC/sub 2/O/sub 4/x2H/sub 2/O finely divided deposit surface properties have been investigated by the methods of electron microscopy, gas adsorption and isotopic exchange in /sup 65/Zn /sup 54/Mn adsorption from aqueous solutions with Mn/sup 2 +/ initial concentration of 4x10/sup -6/ - 5x10/sup -4/ mol/l has been studied using the same deposit. Characteristic frequencies of Zn/sup 2 +/ and Mn/sup 2 +/ transitions between layers, zinc and manganese oxalates masses in the first and second layers and local coefficients of cocrystallization of manganese and zinc oxalates in near-surface layers (lambda=0.38+-0.05 and lambda/sub 2/=0.17+-0.04) have been calculated using representation on successive Zn/sup 2 +/ and Mn/sup 2 +/ transition to three near-surface monolayers and on reverse translation motion. A formula for the connection of lambda sub(..gamma..) coefficients (is a number of the surface layer) with a layer-to-surface distance has been derived. A possibility of the forecast of a dependence of effective cocrystallization coefficient of impurity with growing crystals on crystal growth rate has been revealed.

  6. Electronic transport properties of stuffed compositions of ferromagnetic copper chromium telluride: Cu1+xCr2Te4 (x=0-1)

    We present here a detailed study of electronic transport properties of the metallic-ferromagnetic compounds Cu1+xCr2Te4, having excess Cu atoms with x=0-1, from 2 to 400 K. The stuffing of the copper atoms in the parent structure reduces the ferromagnetic ordering temperature TC from 325 to 156 K, while for the entire range the dependence of the electrical resistance and the thermopower with temperature and the anomalies in them on the magnetic ordering remain similar. All the compounds show a magnon-drag contribution in thermopower as a positive maximum around TC/3, and a T2 - dependence of resistivity at low temperatures. The increasing effects of the short range magnetic ordering in the paramagnetic resistivity are seen with the increase in the stuffing of atoms in these compounds. The transport properties are explained by the current carriers -the holes in a wide energy band dominated by the p-state of Te-atoms, which are scattered by the spindisorder in the paramagnetic phase and from the magnons in the ferromagnetic phase. - Highlights: → Resistivity and the thermopower of series of Cu1+xCr2Te4x=0-1 from 2to600 K. → Spin-disorder scattering of conduction electrons in the paramagnetic phase. → Magnon-drag effects, as a positive maximum at TC/3 in thermopower. → Short range ordering caused by the frustration effects of the interactions by interstitial atoms. → Alloy-like structural and electronic properties by the increase in stuffing of the copper atoms.

  7. Magnetic properties of stuffed copper chromium tellurides Cu1+xCr2+yTe4 (x=0-1, y<0.3)

    We present a detail study of the effect of excess metal atoms on the magnetic properties of Cu1+xCr2+yTe4 at 2-400 K. With the increase in x=0-1 and yac measurements reveal a second transition on cooling below the ferromagnetic ordering; the transition at around 160-180 K intensifies with the excess amount of copper and chromium atoms. The value of spontaneous magnetization at 2 K remains between 2.6 and 2.9μB across all the compositions and it reduces with temperature as M(T)∼A0T3/2+A1T5/2, as expected for the excitation of Bloch's spin waves in a model of the Heisenberg ferromagnet. Our terminal composition Cu1.9Cr2.25Te4 showed only second transition at 160 K with short range magnetic order much above the transition temperature and in the absence of the specific heat jump at this temperature. The magnetic properties are explained as a result of random magnetic anisotropy in the excess-metal compositions induced by the interstitial atomic defects in their parent spinel structure. The large stuffing of cations has been made possible in the telluride compounds because of the large size of tellurium and also by the covalent bonding that stabilizes the defect structure. - Highlights: → Magnetization measurement of ferromagnetic Cu1+xCr2+yTe4, x=0-1 at 2-400 K. → Reduction of TC with no significant changes in the magnetization by the stuffing. → A broad bump in CP around the magnetic transition in the stuffed composition Cu1.9Cr2.2Te4. → Extensive short range ordering in its paramagnetic phase. → Analysis of T3/2-dependence of M(T) and Cp(T) using Bloch's theory of spin-wave.

  8. Charge transport and thermoelectric properties of double-filled Nd1- z Yb z Fe4- x Co x Sb12 skutterudites

    Shin, Dong-Kil; Kim, Il-Ho; Jang, Kyung-Wook; Choi, Soon-Mok; Lee, Soonil; Seo, Won-Seon

    2016-04-01

    p-Type Nd1- z Yb z Fe4- x Co x Sb12 ( z = 0.25, 0.5, 0.75 and x = 0, 0.5, 1.0) skutterudites were synthesized by using encapsulated melting and hot pressing. The effects of Nd/Yb double filling and Co substitution for Fe (charge compensation) on the microstructure, the charge transport, and the thermoelectric properties of the skutterudite specimens were investigated. All specimens were transformed to the skutterudite phase by the annealing process, and a few secondary phases such as marcasite FeSb2 were formed together with the skutterudite phase, although their formation was suppressed with increasing Co content. The lattice constant changed with the filling ratio of Nd/Yb and Fe/Co substitution, which meant that the double filling of Nd/Yb and the substitution of Co for Fe were successfully performed. All specimens showed p-type conduction at temperatures ranging from 323 K to 823 K and exhibited degenerate semiconductor characteristics, in which the electrical conductivity decreased and the Seebeck coefficient increased with increasing temperature. The Seebeck coefficient increased with increasing Nd and Co contents due to the decreased carrier concentration while the electrical conductivity and the thermal conductivity decreased. The maximum Seebeck coefficient was obtained at temperatures in the range from 723 K to 823 K, and the thermal conductivity significantly increased at temperatures above 623 K due to bipolar conduction. The dimensionless figure of merit, ZT, showed maximum values at temperatures ranging from 723 K to 823 K due to the decrease in the Seebeck coefficient (or the decrease in the power factor) and the increase in the thermal conductivity at high temperatures. The maximum ZT = 0.81 was obtained for Nd0.75Yb0.25Fe4Sb12 at 823 K and for Nd0.75Yb0.25Fe3CoSb12 at 723 K.

  9. Magnetic and magnetocaloric properties of Cu1−xZnxFe2O4 (x=0.6, 0.7, 0.8) ferrites

    The effect of Zn substitution on the magnetic and magnetocaloric properties of Cu1−xZnxFe2O4 (x=0.6, 0.7, 0.8) ferrites over a wide temperature range has been investigated. The polycrystalline samples were synthesized using the solid-state reaction at sintering temperature 1050 °C (1323 K) for 2 h and has been characterized by SQUID magnetometry. Magnetization versus temperature showed that all samples exhibit a paramagnetic to ferromagnetic transition with decreasing temperature. The Curie temperature Tc is found to decrease from 373 K for x=0.6 to 140 K for x=0.8 as well as the saturation magnetization Ms which shifts from 100 to 44 emu/gm. The magnetocaloric effect was obtained by measuring a family of M–H curves at set temperature intervals and calculating the entropy change, ΔS for this system using the Maxwell relation. The ΔS of all samples increased with increasing applied field and showed a maximum around their respective Tc. The entropy change (ΔS) decreased with increasing Zn content, whereas the relative cooling power (RCP) slightly increased. The large RCP and ΔS found in Zn substitution Cu–Zn ferrites will be interesting for magnetic refrigeration near room temperature. - Highlights: • Double sintering ceramic technique is used in preparation of samples. • SQUID magnetometry is used to measure magnetic and magnetocaloric properties. • Samples shows a paramagnetic to ferromagnetic transition with decreasing temperature. • The magnetic entropy change (ΔS) shows a maximum around their respective Tc

  10. LiFePO4 Nanostructures Fabricated from Iron(III) Phosphate (FePO4 x 2H2O) by Hydrothermal Method.

    Saji, Viswanathan S; Song, Hyun-Kon

    2015-01-01

    Electrode materials having nanometer scale dimensions are expected to have property enhancements due to enhanced surface area and mass/charge transport kinetics. This is particularly relevant to intrinsically low electronically conductive materials such as lithium iron phosphate (LiFePO4), which is of recent research interest as a high performance intercalation electrode material for Li-ion batteries. Many of the reported works on LiFePO4 synthesis are unattractive either due to the high cost of raw materials or due to the complex synthesis technique. In this direction, synthesis of LiFePO4 directly from inexpensive FePO4 shows promise.The present study reports LiFePO4 nanostructures prepared from iron (III) phosphate (FePO4 x 2H2O) by precipitation-hydrothermal method. The sintered powder was characterized by X-ray diffractometry (XRD), X-ray photoelectron spectroscopy (XPS), Inductive coupled plasma-optical emission spectroscopy (ICP-OES), and Electron microscopy (SEM and TEM). Two synthesis methods, viz. bulk synthesis and anodized aluminum oxide (AAO) template-assisted synthesis are reported. By bulk synthesis, micro-sized particles having peculiar surface nanostructuring were formed at precipitation pH of 6.0 to 7.5 whereas typical nanosized LiFePO4 resulted at pH ≥ 8.0. An in-situ precipitation strategy inside the pores of AAO utilizing the spin coating was utilized for the AAO-template-assisted synthesis. The template with pores filled with the precipitate was subsequently subjected to hydrothermal process and high temperature sintering to fabricate compact rod-like structures. PMID:26328435

  11. Synthesis, structure and magnetic ordering of the mullite-type Bi2Fe(4-x)CrxO9 solid solutions with a frustrated pentagonal Cairo lattice.

    Rozova, M G; Grigoriev, V V; Bobrikov, I A; Filimonov, D S; Zakharov, K V; Volkova, O S; Vasiliev, A N; Antipov, E V; Tsirlin, A A; Abakumov, A M

    2016-01-21

    Highly homogeneous mullite-type solid solutions Bi2Fe(4-x)CrxO9 (x = 0.5, 1, 1.2) were synthesized using a soft chemistry technique followed by a solid-state reaction in Ar. The crystal structure of Bi2Fe3CrO9 was investigated using X-ray and neutron powder diffraction, transmission electron microscopy and (57)Fe Mössbauer spectroscopy (S.G. Pbam, a = 7.95579(9) Å, b = 8.39145(9) Å, c = 5.98242(7) Å, RF(X-ray) = 0.022, RF(neutron) = 0.057). The ab planes in the structure are tessellated with distorted pentagonal loops built up by three tetrahedrally coordinated Fe sites and two octahedrally coordinated Fe/Cr sites, linked together in the ab plane by corner-sharing forming a pentagonal Cairo lattice. Magnetic susceptibility measurements and powder neutron diffraction show that the compounds order antiferromagnetically (AFM) with the Néel temperatures decreasing upon increasing the Cr content from TN ∼ 250 K for x = 0 to TN ∼ 155 K for x = 1.2. The magnetic structure of Bi2Fe3CrO9 at T = 30 K is characterized by a propagation vector k = (1/2,1/2,1/2). The tetrahedrally coordinated Fe cations form singlet pairs within dimers of corner-sharing tetrahedra, but spins on the neighboring dimers are nearly orthogonal. The octahedrally coordinated (Fe,Cr) cations form antiferromagnetic up-up-down-down chains along c, while the spin arrangement in the ab plane is nearly orthogonal between nearest neighbors and collinear between second neighbors. The resulting magnetic structure is remarkably different from the one in pure Bi2Fe4O9 and features several types of spin correlations even on crystallographically equivalent exchange that may be caused by the simultaneous presence of Fe and Cr on the octahedral site. PMID:26661379

  12. One-Pot Synthesis of (NiFe2O4)x-(SrFe12O19)1-x Nanocomposites and Their Microwave Absorption Properties.

    Hazra, Subhenjit; Ghosh, Barun Kumar; Patra, Manoj Kumar; Jani, Raj Kumar; Vadera, Sampat Raj; Ghosh, Narendra Nath

    2015-09-01

    In this paper, we report a simple but novel aqueous solution based 'one-pot' method for preparation of (NiFe2O4)x-(SrFe12O19)1-x nanocomposites consist of hard ferrite-soft ferrite phases. A physical mixing method has also been employed to prepare nanocomposites having same compositions. The effects of synthetic methodologies on the microstructures of the nanocomposites as well as their magnetic and microwave absorption properties have been evaluated. Crystal structures and microstructures of these composites have been investigated by using X-ray diffraction, transmission electron microscope and scanning electron microscope. In the nanocomposites, prepared by both methods, presence of nanocrystalline NiFe2O4 and SrFe12O19 phases was detected. However, nanocomposites, prepared by one-pot method, possessed better homogeneous distribution of hard and soft ferrite phases than the nanocomposites, prepared by physical mixing method. Nanocomposites, prepared by one-pot method, demonstrated significant spring exchange coupling interaction between hard and soft ferrite phases and exhibited magnetically single phase behaviour. The spring exchange coupling interaction enhanced the magnetic properties (high saturation magnetization and coercivity) and microwave absorption properties of the nanocomposites, prepared by one-pot method, in comparison with the nanocomposites prepared by physical mixing method as well as pure NiFe2O4 and SrFe12O19 nanoparticles. Minimum reflection loss of the composite was ~ -17 dB (i.e., 98% absorption) at 8.2 GHz for an absorber thickness of 3.2 mm. PMID:26716212

  13. N = 1 supersymmetric SU(4) x SU(2)L x SU (2)R effective theory from the weakly coupled heterotic superstring

    In the context of the free-fermionic formulation of the heterotic superstring, we construct a three-generation N = 1 supersymmetric SU(4) x SU(2)L x SU(2)R model supplemented by an SU(8) hidden gauge symmetry and five Abelian factors. The symmetry breaking to the standard model is achieved using vacuum expectation values of a Higgs pair in (4,2R) + (4-bar,2R) at a high scale. One linear combination of the Abelian symmetries is anomalous and is broken by vacuum expectation values of singlet fields along the flat directions of the superpotential. All consistent string vacua of the model are completely classified by solving the corresponding system of F- and D-flatness equations including non-renormalizable terms up to sixth order. The requirement of existence of electroweak massless doublets imposes further restrictions to the phenomenologically viable vacua. The third generation fermions receive masses from the tree-level superpotential. Further, a complete calculation of all non-renormalizable fermion mass terms up to fifth order shows that in certain string vacua the hierarchy of the fermion families is naturally obtained in the model as the second and third generation fermions earn their mass from fourth- and fifth-order terms. Along certain flat directions it is shown that the ratio of the SU(4) breaking scale and the reduced Planck mass is equal to the up quark ratio ((mc)/(mt)) at the string scale. An additional prediction of the model, is the existence of a U(1) symmetry carried by the fields of the hidden sector, ensuring thus the stability of the lightest hidden state. It is proposed that the hidden states may account for the invisible matter of the universe

  14. Structural, optical and electrical properties of Cu{sub 2}FeSnX{sub 4} (X = S, Se) thin films prepared by chemical spray pyrolysis

    Khadka, Dhruba B.; Kim, JunHo, E-mail: jhk@inu.ac.kr

    2015-07-25

    Highlights: • CFTS(Se) thin films have been synthesized by low-cost spray-based deposition. • The fabricated films were found to be of stannite structure and p-type conductivity. • Band gaps of CFTS and CFTSe thin films are 1.37 and 1.11 eV, respectively. - Abstract: We report on fabrication of polycrystalline Cu{sub 2}FeSnX{sub 4} (X = S, Se) thin films by chemical spray pyrolysis subsequent with post-sulfurization and selenization. The post-annealing of as-sprayed Cu{sub 2}FeSnS{sub 4} (CFTS) films in sulfur and selenium ambient demonstrated drastically improved surface texture as well as crystallinity. The crystal lattice parameters calculated from X-ray diffraction patterns for post-annealed films were found to be consistent with stannite structure. The fabricated Cu{sub 2}FeSnS{sub 4} (CFTS) and Cu{sub 2}FeSnSe{sub 4} (CFTSe) films showed p-type conductivity with carrier concentration in the range of 10{sup 21} cm{sup −3} and mobility ∼1–5 cm{sup 2} V{sup −1} s{sup −1}. The band gap energies of post-sulfurized CFTS and post-selenized CFTSe films were estimated to be ∼1.37 eV and ∼1.11 eV with an error of ±0.02 eV by UV–Vis absorption, respectively, which are promising for photovoltaic application.

  15. High-temperature dissolution of nickel chromium ferrites by oxalic acid and nitrilotriacetic acid

    A study of the dissolution of a number of spinel-type oxides containing iron(III) ions by oxalic acid and nitrilotriacetic acid (NTA) is reported. Increasing the chromium content of oxides of general composition Nisub(0.6)Crsub(x)Fesub(2.4-x)O4 (x = 0.3 to 1.5) brought about a marked reduction in dissolution rate, and it is suggested that this arises by a mechanism involving a change from kink-site attack to ledge-site attack as the former become 'blocked' by less reactive chromium(III) ions. The Nisub(0.6)Crsub(0.6)Fesub(1.8)O4 oxide was investigated in more detail. The concentration dependences determined suggest that both oxalic acid and NTA are adsorbed at surface sites prior to dissolution. NTA brings about dissolution simply by 'complexing' attack, but with oxalic acid it was not possible to distinguish directly between complexing and reductive attack. The divalent cation also plays a role, for in the dissolution of a number of ferrites, AFe2O4 (A = Co, Fe, Mn, Ni), in oxalic acid appreciable differences in dissolution rate were found, the order of reactivity being Fe > Mn > Co > Ni. The reasons for this are discussed. (author)

  16. Optoelectronic properties of XIn2S4 (X = Cd, Mg) thiospinels through highly accurate all-electron FP-LAPW method coupled with modified approximations

    Highlights: • Highly accurate all-electron FP-LAPW+lo method is used. • New physical parameters are reported, important for the fabrication of optoelectronic devices. • A comparative study that involves FP-LAPW+lo method and modified approximations. • Computed band gap values have good agreement with the experimental values. • Optoelectronic results of fundamental importance can be utilized for the fabrication of devices. - Abstract: We report the structural, electronic and optical properties of the thiospinels XIn2S4 (X = Cd, Mg), using highly accurate all-electron full potential linearized augmented plane wave plus local orbital method. In order to calculate the exchange and correlation energies, the method is coupled with modified techniques such as GGA+U and mBJ-GGA, which yield improved results as compared to the previous studies. GGA+SOC approximation is also used for the first time on these compounds to examine the spin orbit coupling effect on the band structure. From the analysis of the structural parameters, robust character is predicted for both materials. Energy band structures profiles are fairly the same for GGA, GGA+SOC, GGA+U and mBJ-GGA, confirming the indirect and direct band gap nature of CdIn2S4 and MgIn2S4 materials, respectively. We report the trend of band gap results as: (mBJ-GGA) > (GGA+U) > (GGA) > (GGA+SOC). Localized regions appearing in the valence bands for CdIn2S4 tend to split up nearly by ≈1 eV in the case of GGA+SOC. Many new physical parameters are reported that can be important for the fabrication of optoelectronic devices. Optical spectra namely, dielectric function (DF), refractive index n(ω), extinction coefficient k(ω), reflectivity R(ω), optical conductivity σ(ω), absorption coefficient α(ω) and electron loss function are discussed. Optical’s absorption edge is noted to be 1.401 and 1.782 for CdIn2S4 and MgIn2S4, respectively. The prominent peaks in the electron energy spectrum situated between 15 eV and

  17. Acid Rain.

    Openshaw, Peter

    1987-01-01

    Provides some background information on acid deposition. Includes a historical perspective, describes some effects of acid precipitation, and discusses acid rain in the United Kingdom. Contains several experiments that deal with the effects of acid rain on water quality and soil. (TW)

  18. Erosive effects of acidic center-filled chewing gum on primary and permanent enamel

    Bolan M

    2008-01-01

    Full Text Available Background: The higher incidence of dental erosion in children and teenagers possibly reflects a high intake of acidic food and beverages as well as a more frequent diagnosis on this condition. Aim: The aim of this study was to evaluate the erosive potential of acidic filling of chewing gum in primary and permanent enamel. Methods and Materials: Eighty enamel blocks (40 primary and 40 permanent teeth were used and randomly distributed into eight groups. Groups were divided according to types of dental substrates (permanent or primary, frequency of exposure to the acidic substance (2X or 4X/day, and concentration (pure or diluted. Exposure time to the acidic content of the chewing gum was five minutes under agitation, during five days. Results: All groups showed a significant decrease in surface microhardness (P < 0.001. There was neither any significant difference in the frequency of exposure to the acidic content nor to the types of dental substrates. There was a statistically significant difference between D1 (pure, 2X/day and D2 (diluted, 2X/day (P = 0.002, D3 (pure, 4X/day and D4 (diluted, 4X/day (P = 0.009 regarding the concentration, then the diluted acid content was associated with a greater decrease in microhardness. Conclusion: It is concluded that the acidic filling of a chewing gum reduced the microhardness of primary and permanent enamel.

  19. Investigation of solubility of uranium (4) salfate-fluoride salts in sulfuric acid

    Electrochemical reduction of uranyl ions was used to prepare sulfate-fluoride solutions of U(4) from which the crystallohydrates UFSO4HSO4x6H2O and UF2SO4x41/2H2O were isolated. Their solubility in H2SO4 was studied. The chemical analysis of the solid and the liquid phases for uranium, fluoride and sulphate-ions was carried out after equilibrium had been reached, which required 3 hours stjrring. As the temperature was raised from 15 to 55 deg C, the solubility of UFSO4HSO4x6H2O increased from 14.09 to 20.34 mass % UFSO4HSO4. At 25 deg C with the increase in the acid concentration from 0.05 to 2.0 M the solubility of this salt decreased from 16.25 to 7.85 mass % UFSO4HSO4. As the temperature was raised from 15 to 20 deg C, the solubility of UF2SO4x41/2H2O in 0.25 M acid increased from 6.82 to 12.80 mass % UF2SO4. At 55 deg it decreased to 6.54 mass % UF2SO4 due to partial dehydration and conversion into less soluble UF2SO4x3H2O. At 25 deg C the increase in the acid concentration from 0.05 to 2.0 M brought about the decrease in UF2SO4x41/2H2O solubility from 7.41 to 5.93 mass % UF2SO4

  20. Folic Acid

    ... found naturally in some foods, including leafy vegetables, citrus fruits, beans (legumes), and whole grains. Folic acid ... mcg of folic acid every day for good health. But older adults need to be sure they ...

  1. Population dose estimation from a hypothetical release of 2.4 x 106 curies of noble gases and 1 x 104 curies of 131I at the Three Mile Island Nuclear Station, Unit 2

    Beginning on March 28, 1979, a sequence of events occurred at the Three Mile Island Nuclear Station Unit 2 (TMINS-2) nuclear power reactor which resulted in the accidental release of approximately 2.4 x 106 Ci of noble gases and 13 to 15 Ci 131I. A comprehensive study of this incident has been reported by the President's Commission on the Accident at Three Mile Island. As part of this study, the Technical Assessment Task Group for the Commission addressed a series of alternative event scenarios, including the potential for a higher release of 131I. As a continuation of this task, this report presents the estimated collective dose to the population within 50 miles of TMINS-2 from a hypothetical release of 2.4 x 106 Ci of noble gases and 1 x 104 Ci 131I by the methodology of atmospheric dispersion modeling and population dose estimation through the inhalation, ingestion and immersion exposure pathways

  2. Low-temperature electrical resistance of the U(Cu,Ni)4Al8 system and magnetic and electrical properties of ScCu4+xAl8-x

    The electrical resistance measurements of the UCu4-xNixAl8 were performed in the temperature range 30 mK-4.2 K. Also the samples without Ni but with various Al/Cu ratio were investigated. All these compounds exhibit strong decrease in R(T) plot below 1 K which results from a presence of CuAl2 as impurity. The ScCu4+xAl8-x alloys exist as the single-phase materials for the composition range 0 ≤ x ≤ 2.15. At low temperatures the alloys are weakly paramagnetic whereas at higher temperatures weakly diamagnetic properties are observed. Their electrical resistivity is low and weakly temperature dependent. No anomalies in both χ(T) and ρ(T) plots can be detected. (orig.)

  3. Study on Luminescence Properties and Crystal-Lattice Environment of Eu2+ in Sr4-xMgxSi3O8Cl4∶Eu2+ Phosphor

    夏志国; 孙家跃; 杜海燕

    2004-01-01

    According to the Van Uitert experimental equation, crystal-lattice environment of Eu2+ in the Sr4Si3O8Cl4 crystal was discussed. By adding Mg2+ to the host lattice, Sr4-xMgxSi3O8Cl4∶Eu2+ was synthesized and the emission peak shifted from blue-green (488 nm) to blue-violet (411 nm) with the increase of amount of the magnesium which replaced the strontium. By analyzing the spectra of Sr4-xMgxSi3O8Cl4∶Eu2+ the two Eu2+ emission centers were found because of the change of crystal-lattice environment in the host and the crystal structure was obtained by X-ray diffraction data.

  4. Equilibrium coefficient of cocrystallization in the system ZnC/sub 2/O/sub 4/x2H/sub 2/O-Mn(2)-H/sub 2/O

    Berdonosova, D.G.; Pencheva, Zh.; Burlakova, E.V.

    1984-01-01

    To determine the equilibrium volume coefficient of cocrystallization (D) of the Mn(2+) impurity, labelled by /sup 54/Mn radionuclide with sediment ZnC/sub 2/O/sub 4/x2H/sub 2/O (Mn concentration in aqueous solution is 4x10/sup -6/ - 1.86x10/sup -3/ mol/l) three methods are used: 1) spontaneous sediment ripening; 2) sediment ripening alternating with wearing of a solid phase; 3) technique of express D determination for difficultly soluble substances in open systems. It is shown that the 1 and 2 methods lead to the same stationary state of the system for which D--0.100+-0.006, and D magnitude is not dependent on initial Mn concentration. The 3 method gives overstated magnitudes of D=O.16+-0.04.

  5. On the Imbalance of the Dielectric Constant of the PbLixNb3xZr0.51Ti0.49-4xO3 Compound

    Despa, F.

    1996-01-01

    In the present paper, the dielectric behaviour of the PbLixNb3xZr0.51Ti0.49-4xO3 ( PLNZT) system is analyzed. It is shown that the decrease in the dielectric constant with respect to an increase of the impurity content may be due to an aggregation trend of the interacting off-centre dipoles rather than due to cooperative phenomena which renormalizes the dipole moment of the off-centre impurity.

  6. A new family of wurtzite-phase Cu2ZnAS4-x and CuZn2AS4 (A = Al, Ga, In) nanocrystals for solar energy conversion applications.

    Ghosh, Anima; Palchoudhury, Soubantika; Thangavel, Rajalingam; Zhou, Ziyou; Naghibolashrafi, Nariman; Ramasamy, Karthik; Gupta, Arunava

    2016-01-01

    A new family of quaternary semiconductors Cu2ZnAS4-x and CuZn2AS4 (A = Al, Ga, In) has been synthesized in the form of wurtzite phase nanocrystals for the first time. The nanocrystals can be converted to the stannite phase via thermal annealing under a N2 atmosphere. A direct band gap in the visible wavelength region combined with a high absorption cross-section makes these materials promising for solar energy conversion applications. PMID:26466863

  7. Lipide und Kohlenhydrate unter antihypertensiver Therapie mit den b-Blockern Celiprolol und Metoprolol und dem ACE-Hemmer Benazepril – eine 4x4 cross-over Studie an Typ-2-Diabetikern

    Werz, Ursula

    2009-01-01

    Studienaufbau und Methoden: Unsere Studie untersuchte die drei Antihypertensiva Celiprolol (200 mg), Metoprolol (95 mg) und Benazepril (5 mg) auf ihre blutdrucksenkende Wirkung als prospektive, placebokontrollierte, doppelverblindete und randomisierte Kurzzeitstudie in einer 4x4 cross-over Konzeption mit drei Verumphasen und einer Placebophase zu je vier Wochen, jeweils getrennt durch eine zweiwöchige Wash-out-Phase, anhand eines kleinen Patientenkollektivs (12 PatientInnen) und verglich sie ...

  8. Mixed thio/oxo orthovanadates Na{sub 3}[VS{sub x}O{sub 4-x}] (x = 2, 3): Synthesis - crystal structures - properties; Gemischte Thio/Oxo-Orthovanadate Na{sub 3}[VS{sub x}O{sub 4-x}] (x = 2, 3): Darstellung - Strukturen - Eigenschaften

    Schnabel, S.; Roehr, C. [Inst. fuer Anorganische und Analytische Chemie, Univ. Freiburg (Germany)

    2005-05-01

    Mixed sodium thio/oxo orthovanadates(V), dark red Na{sub 3}[VS{sub 3}O] and orange red Na{sub 3}[VS{sub 2}O{sub 2}], were synthesized via reactions in the melt starting from V, Na, Na{sub 2}S, Na{sub 2}O and sulfur. The structure of the low temperature phase of Na{sub 3}[VS{sub 3}O] (space group Pnma, a = 589.5(3), b = 962.8(5), c = 1186.6(6) pm, Z = 4, R1 = 0.0494) contains anions [VS{sub 3}O]{sup 3-} almost identical to those known from the high temperature form, {beta}-Na{sub 3}[VS{sub 3}O] (space group Cmc2{sub 1}, a = 968.4(4), b = 1194.6(4), c = 590.5(2) pm, Z = 4, R1 = 0.0291). The second order phase transition between these two forms at 536 C was studied by temperature dependent powder diffraction and explained on the basis of a comparison of the anion packing in the two related structures. The packing of the dithiodioxovanadate anions in Na{sub 3}[VS{sub 2}O{sub 2}] (space group Pbca, a = 1162.7(2), b = 592.71(12), c = 1766.7(4) pm, Z = 8, R1 = 0.0312) is also closely related. The chemical bonding in the anions [VS{sub 3}O]{sup 3-} and [VS{sub 2}O{sub 2}]{sup 3-} of approximately ideal C{sub 3v} and C{sub 2v} symmetry is discussed on the basis of FP-LAPW band structure calculations and force constants obtained from Raman spectroscopy. The decrease of the calculated band gaps with increasing S content x in Na{sub 3}[VS{sub x}O{sub 4-x}] is in accordance with the optical properties showing a gradually deepening of the crystal and solution colour. Discernible trends in the chemical bonding in this series of mixed thio-oxo anions also include the amount of {pi} bonding of the V-O and V-S bonds and the corresponding variation of force constants and V-O/V-S distances. (orig.)

  9. Ibotenic acid and thioibotenic acid

    Hermit, Mette B; Greenwood, Jeremy R; Nielsen, Birgitte;

    2004-01-01

    In this study, we have determined and compared the pharmacological profiles of ibotenic acid and its isothiazole analogue thioibotenic acid at native rat ionotropic glutamate (iGlu) receptors and at recombinant rat metabotropic glutamate (mGlu) receptors expressed in mammalian cell lines....... Thioibotenic acid has a distinct pharmacological profile at group III mGlu receptors compared with the closely structurally related ibotenic acid; the former is a potent (low microm) agonist, whereas the latter is inactive. By comparing the conformational energy profiles of ibotenic and thioibotenic acid with...... the conformations preferred by the ligands upon docking to mGlu1 and models of the other mGlu subtypes, we propose that unlike other subtypes, group III mGlu receptor binding sites require a ligand conformation at an energy level which is prohibitively expensive for ibotenic acid, but not for...

  10. PELATIHAN LARI INTERVAL 8 X 100 M, LEBIH BAIK DARI PELATIHAN LARI INTERVAL 4 X 200 M DAN 2 X 400 M DALAM MENINGKATKAN KECEPATAN LARI 400 M SISWA SMK NEGERI 5 DENPASAR

    Ni Ketut Ayu Juliasih

    2013-07-01

    Full Text Available This study aimed to assess the increase of speed of the 400 m running obtained from a training of interval running of 800 m distance programmed  in three types of models and to find out which one of the three training models gave the greatest improvement of speed. The three models of training were interval sprint of 8 x 100 meters, 4 x 200 meters, and 2 x 400 meters, carried out in 4 sets, 3 times a week, for a 6 week duration. This study was an experimental study using the Randomized Pre and Post Test Group Design. The study subjects comprised 24 students of SMK Negeri 5 Denpasar, who were divided into 3 groups of 8 students each. Group 1 was assigned to 8 x 100 m run, group 2 to 4 x 200 m run, and group 3 to 2 x 400 m run training, respectively. The data were analyzed accordingly with the test of T-Paired, One-way Anova, and LSD. The result of the T-Paired test on each group before anf after training showed a significant mprovement of the running speed (p<0.05. Therefore, indicating an improvement of 400 m running speed was achieved in each group. The One-Way Anova test showed a significant difference was found among the three groups in the increase of running speed obtained after training (p<0.05. The LSD test showed there was a significant difference of the increase of running speed between Group 1 and 2, and between Group 1 and 3 (p<0.05. There was no significant difference of speed found between Group 2 and 3 (p>0.05. Therefore, the training of interval 8 x 100 meters run was more effective in increasing the running speed as compared with interval 4 x 200 meters and 2 x 400 meters run, respectively, among the students of SMK 5 Denpasar.

  11. Study of the electronic properties of Zn{sub 0.8–4x}Ho{sub x}O{sub y} (0.05 ≤ x ≤ 0.09) by X-ray absorption and photoemission spectroscopy

    Ekicibil, A. [Physic Department, University of Cukurova, 01330 Adana (Turkey); Ozkendir, O.M. [Tarsus Technology Faculty, Mersin University, 33400 Tarsus (Turkey); Farha, A.H. [Department of Electrical and Computer Engineering, Old Dominion University, Norfolk, VA 23529 (United States); Department of Physics, Faculty of Science, Ain Shams University, Cairo 11566 (Egypt); Ufuktepe, Y., E-mail: ufuk@cu.edu.tr [Physic Department, University of Cukurova, 01330 Adana (Turkey)

    2015-07-15

    Highlights: • The electronic structure of Ho doped ZnO was investigated by XANES and XPS. • The electronic structure was directly influenced by the Ho concentration in the ZnO. • The crystal structure showed little/no correlation to the substitution of Ho. • The substitution of Ho causes a weaker antiferromagnetic interaction. • The blue shift in band gap is observed and discussed. - Abstract: The electronic structure of Zn{sub 0.8–4x}Ho{sub x}O{sub y} (0.05 ≤ x ≤ 0.09) was investigated using X-ray absorption near edge structure (XANES) and X-ray photoelectron spectroscopy (XPS). Samples were prepared by the solid state reaction method. Using X-ray absorption spectroscopy, the investigation of M{sub 4,5} absorption edge of Ho revealed that the electronic structure was directly influenced by the Ho concentration in the Zn{sub 0.8–4x}Ho{sub x}O{sub y} sample whereas the crystal structure properties showed little/no correlation to the substitution of Ho. The electronic structure differs substantially from those of the reference ZnO. The O K-edge spectra suggest that the combination of the Ho with ZnO enhances the effective charge of the O ions. A systematic study on the composition from lower to higher value of Ho dopant showed the blue shift in band gaps and is discussed in the view of the electronic structure of the Zn{sub 0.8–4x}Ho{sub x}O{sub y} samples. The inverse susceptibility (1/χ) against temperature curves is plotted to identify the magnetic contribution. Those curves indicate that the substitution of Ho into the ZnO compound causes a weaker antiferromagnetic (AFM) interaction.

  12. Study of the electronic properties of Zn0.8–4xHoxOy (0.05 ≤ x ≤ 0.09) by X-ray absorption and photoemission spectroscopy

    Highlights: • The electronic structure of Ho doped ZnO was investigated by XANES and XPS. • The electronic structure was directly influenced by the Ho concentration in the ZnO. • The crystal structure showed little/no correlation to the substitution of Ho. • The substitution of Ho causes a weaker antiferromagnetic interaction. • The blue shift in band gap is observed and discussed. - Abstract: The electronic structure of Zn0.8–4xHoxOy (0.05 ≤ x ≤ 0.09) was investigated using X-ray absorption near edge structure (XANES) and X-ray photoelectron spectroscopy (XPS). Samples were prepared by the solid state reaction method. Using X-ray absorption spectroscopy, the investigation of M4,5 absorption edge of Ho revealed that the electronic structure was directly influenced by the Ho concentration in the Zn0.8–4xHoxOy sample whereas the crystal structure properties showed little/no correlation to the substitution of Ho. The electronic structure differs substantially from those of the reference ZnO. The O K-edge spectra suggest that the combination of the Ho with ZnO enhances the effective charge of the O ions. A systematic study on the composition from lower to higher value of Ho dopant showed the blue shift in band gaps and is discussed in the view of the electronic structure of the Zn0.8–4xHoxOy samples. The inverse susceptibility (1/χ) against temperature curves is plotted to identify the magnetic contribution. Those curves indicate that the substitution of Ho into the ZnO compound causes a weaker antiferromagnetic (AFM) interaction

  13. P-T PHASE DIAGRAM AND GOLD VALENCE STATE OF NEW GOLD MIXED-VALENCE COMPLEXES, Cs2[AuIX2][AuIIIY4](X, Y = Cl, Br, I; X ¹ Y

    K. Ikeda

    2004-12-01

    Full Text Available Cs2[AuIX2][AuIIIX4](X = Cl, Br, and I is well known for the perovskite-type gold mixed-valence system. This system undergoes pressure-induced and photo-induced Au valence transition from the mixed valence state of AuI,III to the single valence state of AuII. Recently, we have succeeded in synthesizing new gold mixed-valence complexes having perovskite-type structure, Cs2[AuIX2][AuIIIY4](X, Y = halogen, X ¹ Y, in organic solvent by using a new method. This hetero-halogen bridged gold mixed-valence system was confirmed by means of Raman spectroscopy. From the analysis of 197Au Mössbauer spectra, it was elucidated that the charge transfer interaction between AuI(5dx2-y2 and AuIII(5dx2-y2in the a-b plane becomes dominant for the AuI-AuIII interaction in Cs2[AuIX2][AuIIIY4] (X, Y = Cl, Br, and I in the order of X = Cl < Br < I, where Y is fixed. In order to elucidate the Au valence transition for Cs2[AuIX2][AuIIIY4], we have investigated the X-ray diffraction and Raman spectra under high pressure. Moreover, we have synthesized TlAuX3(X = Cl and Br having cubic perovskite structure and highly conducting behavior. The Au valence state in TlAuX3 is considered to be AuII at ambient pressure.

  14. Sn2BrxI4-x(g) and Sn2BryI3-y (x=0-4, y=0-3) Species: Mass Spectrometrix Evidence and Quantum-Chemical Studies

    Saloni, J.; Roszak, S.; Miller, M; Hilpert, K.; Leszczynski, J.

    2004-01-01

    Dimeric gaseous species Sn2BrxI4-x, = 0-4, were detected by Knudsen effusion mass spectrometry. Fragment ionic species Sn2BryI3-y+, y = 0-3, yielded by electron bombardment were identified in mass spectra of SnBr2-SnI2 equilibrium vapors. The structure and bonding of identified ions and neutral precursors were studied by quantum-chemical methods. Enthalpies and entropies of the anion-exchange reactions involving gaseous dimeric species were estimated by the use of mass spectrometric and theor...

  15. PELATIHAN LARI INTERVAL 8 X 100 M, LEBIH BAIK DARI PELATIHAN LARI INTERVAL 4 X 200 M DAN 2 X 400 M DALAM MENINGKATKAN KECEPATAN LARI 400 M SISWA SMK NEGERI 5 DENPASAR

    Ni Ketut Ayu Juliasih

    2013-01-01

    This study aimed to assess the increase of speed of the 400 m running obtained from a training of interval running of 800 m distance programmed  in three types of models and to find out which one of the three training models gave the greatest improvement of speed. The three models of training were interval sprint of 8 x 100 meters, 4 x 200 meters, and 2 x 400 meters, carried out in 4 sets, 3 times a week, for a 6 week duration. This study was an experimental study using the Randomized Pre and...

  16. Thermal Expansion and Compressibility in Superconducting NaxCoO2o4xD2O (x?1/3): Evidence for Pressure-Induced Charge Redistribution

    Jorgensen, J. D.; Avdeev, M.; Hinks, D. G.; Barnes, P. W.; Short, S.(Queen Mary University of London, School of Physics and Astronomy, London, United Kingdom)

    2005-01-01

    We have performed thermal expansion and compressibility measurements on the recently discovered superconducting material NaxCoO2*4xD2O (x=1/3) using neutron powder diffraction over the temperature range 10-295 K and the pressure range 0-0.6 GPa. Pressure measurements were done in a helium-gas pressure cell. Both the thermal expansion and compressibility are very anisotropic, with the largest effects along the c axis, as would be expected for a layered material with weak hydrogen bonding nomin...

  17. Comparison of the Giemsa C-banded karyotypes of the three subspecies of Psathyrostachys fragilis, subspp. villosus (2x), secaliformis (2x, 4x), and fragilis (2x) (Poaceae), with notes on chromosome pairing

    Linde-Laursen, I.; Baden, C.

    1994-01-01

    The karyotypes of diploid P. fragilis subsp. villosus (2n = 2x = 14) and tetraploid subsp. secaliformis (2n = 4x = 28) were studied by Giemsa C- and N-banding, and AgNO3 staining and compared with the karyotype of subsp. fragilis (2x). The complements of subsp. villosus and subsp. fragilis were...... metacentrics. Chromocentres were very small and the amount of constitutive heterochromatin was low. N-banding stained chromosomes uniformly. The basic karyotypes of the P. fragilis taxa were similar to those of P. juncea, P. lanuginosa, and P. stoloniformis supporting a close relationship and the presence of a...

  18. 40Gbit/s-class-λ-tunable WDM/TDM-PON using λ-selectable B-Tx and 4 x M cyclic AWG router for flexible photonic aggregation networks.

    Nakamura, Hirotaka; Taguchi, Katsuhisa; Tamaki, Shinya; Mizuno, Takayuki; Hashizume, Yasuaki; Yamada, Takashi; Ito, Mikitaka; Takahashi, Hiroshi; Kimura, Shunji; Yoshimoto, Naoto

    2013-01-14

    This paper proposes a 40Gbit/s-class-λ-tunable WDM/TDM-PON for flexible photonic aggregation networks that achieves the aggregation of a large number of users using the DWBA algorithm without an L2-SW. It also clarifies the scalability of the proposed system in terms of the transmission distance and the number of users. A λ-switching transmission experiment was conducted using a newly developed 10Gbit/s x 4λ selectable B-Tx and 4 x 4 cyclic AWG router. PMID:23388940

  19. [Gastric Acid].

    Ruíz Chávez, R

    1996-01-01

    Gastric acid, a product of parietal cells secretion, full fills multiple biological roles which are absolutely necessary to keep corporal homeostasis. The production of the acid depends upon an effector cellular process represented in the first step by histamine, acetilcholine and gastrin, first messengers of the process. These interact with specific receptors than in sequence activate second messengers -cAMP and the calcium-calmodulin system- which afterwards activate a kinase. An specific protein is then phosphorilated by this enzyme, being the crucial factor that starts the production of acid. Finally, a proton bomb, extrudes the acid towards the gastric lumen. The secretion process mentioned above, is progressive lyactivated in three steps, two of which are stimulators -cephalic and gastric phases- and the other one inhibitor or intestinal phase. These stages are started by mental and neurological phenomena -thought, sight, smell or memory-; by food, drugs or other ingested substances; and by products of digestion. Changes in regulation of acid secretion, in the structure of gastro-duodenal mucosal barrier by a wide spectrum of factors and agents including food, drugs and H. pylori, are the basis of acid-peptic disease, entity in which gastric acid plays a fundamental role. From the therapeutic point of view, so at the theoretical as at the practical levels, t is possible to interfere with the secretion of acid by neutralization of some of the steps of the effector cellular process. An adequate knowledge of the basics related to gastric acid, allows to create strategies for the clinical handling of associated pathology, specifically in relation to peptic acid disease in all of the known clinical forms. PMID:12165790

  20. Doping phosphoric acid in polybenzimidazole membranes for high temperature proton exchange membrane fuel cells

    He, Ronghuan; Li, Qingfeng; Jensen, Jens Oluf;

    2007-01-01

    Polybenzimidazole (PBI) membranes were doped in phosphoric acid solutions of different concentrations at room temperature. The doping chemistry was studied using the Scatchard method. The energy distribution of the acid complexation in polymer membranes is heterogeneous, that is, there are two...... different types of sites in PBI for the acid doping. The protonation constants of PBI by phosphoric acid are found to be 12.7 L mol(-1) (K-1) for acid complexing sites with higher affinity, and 0.19 L mol(-1) (K-2) for the sites with lower affinity. The dissociation constants for the complexing acid onto...... these two types of PBI sites are found to be 5.4 X 10(-4) and 3.6 X 10(-2), respectively, that is, about 10 times smaller than that of aqueous phosphoric acid in the first case but 5 times higher in the second. The proton conducting mechanism is also discussed....

  1. Structural, magnetic and dielectric properties of Ni(1_x)Zn(x)Fe2O4 (x = 0,0.5 and 1) nanoparticles synthesized by chemical co-precipitation method.

    Rathore, Deepshikha; Kurchania, Rajnish; Pandey, R K

    2013-03-01

    Ni(1-x)Zn(x)Fe2O4 (x = 0, 0.5 and 1) ferrite nanoparticles were synthesized by chemical co-precipitation method. X-ray diffraction technique and Rietveld refinement were used to investigate the structural characteristics and determination of the particle size which was found to decrease from 4.9 to 4.1 nm as a function of increasing Zn from 0 to 1.0. Vibrating sample magnetometer was used to study magnetic properties of nickel zinc ferrite nanoparticles. Field-dependent magnetization measurements (M-H curve) at 300 K revealed that Zn substitutions on inverse spinel nickel ferrites enhance the magnetic properties. Magnetization as a function of temperature showed the superparamagnetic behavior of Ni(1-x)Zn(x)Fe2O4 (x = 0,0.5 and 1) nanoparticles. Dielectric permittivity and a.c. conductivity were measured as a function of frequency from 100 kHz to 1 MHz at certain temperatures. The observed response in a.c. conductivity as a function of log of frequency of these nickel zinc ferrite systems was believed to be due to the presence of Maxwell-Wagner type interfacial polarization and hopping of electron by means of quantum mechanical tunneling. PMID:23755597

  2. Influence of N–H–O hydrogen bonds on the structure and properties of (K1−x(NH4)xH2PO4) proton glasses: a single crystal neutron diffraction study

    It has been known for quite some time now that proton dynamics plays a key role in the structural ferroelectric (FE)/antiferroelectric (AFE) phase transition in the crystals belonging to the potassium dihydrogen phosphate crystal family. Mixed crystals belonging to this family having the composition M1−x(NW4)xW2AO4, where M = K, Rb, Cs, W = H, D, and A = P, As, exhibit proton glass behavior due to frustration between FE and AFE ordering; these proton glasses do not undergo any structural phase change but retain their room temperature structure down to very low temperatures. Single crystal neutron diffraction investigations of four mixed crystals with composition (K1−x(NH4)xH2PO4), where x = 0.0, 0.29, 0.67 1.0, were undertaken with the intention to investigate the effect of the local structural deviations on the overall average structure of the crystals and correlate these structural changes to the presence or absence of a structural phase transition in these crystals. Hydrogen bonding is shown to play a key role in the changing nature of the mixed crystals as the composition varies from the potassium rich ferroelectric region to the proton glass region to the ammonium rich antiferroelectric region. (paper)

  3. X-ray Absorption Near Edge Structure (XANES) study of YBaCo4-xFexO7 (x = 0.2, 0.4, 0.5, 0.6, and 0.8) using synchrotron radiation

    YBaCo4O7 is an important material in the class of cobaltates which shows a high degree of magnetic frustration. The crystal structure of YBaCo4O7 is built up of Kagome sheets of CoO4 tetrahedra, linked by triangular layers of CoO4 tetrahedra. The ratio of Co ion numbers in the Kagome to triangular lattices is 3:1 and it shows mixed valency of Co consisting of Co2+ and Co3+ states. Here, we report the XANES measurements on Fe doped YBaCo4O7, i.e., YBaCo4-xFexO7 compounds using Synchrotron radiation. The shifts of the K-absorption edges of Co have been investigated for these samples as a function by Fe doping concentration. The measurements have been carried out at the recently commissioned Dispersive EXAFS beamline (BL-8) at INDUS-2 Synchrotron Radiation source at RRCAT, Indore. From the XANES spectra of the samples it is found that that Co K absorption edge (E0) of YBaCo4-xFexO7 samples is shifted gradually to the higher energy as the Fe concentration (x) in the samples is increased from 0.2 to 0.8

  4. Structural Characterization of the Intermetallic Phase EuZnxIn4-x (x ≅ 1.1-1.2). Zn and In Site-Preferences in the BaAl4 Structure-Type from Computational Analysis

    The ternary phase EuZnxIn4-x has been identified as the main product of reactions of Eu, Zn, and In by using the In-flux method and characterized by both powder and single-crystal X-ray diffraction. The structure belongs to the common BaAl4-type (tetragonal space group I4/mmm, Pearson code tI10) with lattice parameters of a = 4.5610(9) A, c = 12.049(3) A for composition EuZn1.10(12)In2.90 and a = 4.5463(3) A, c = 12.028(2) A for composition EuZn1.18(2)In2.82, respectively. In this structure, the Eu atoms are situated at the center of 18-vertex Fedorov polyhedra made of Zn and In atoms, where the 4d site is preferentially occupied by In and the 4e site is occupied by randomly mixed Zn and In atoms. Theoretical investigations using tight-binding linear muffin-tin orbital (TB-LMTO) method provide rationale for the observed site preferences and suggest potentially wider homogeneity range than the experimentally established for EuZnxIn4-x (x ≅ 1.1)

  5. New pressure induced phase transitions in mullite-type Bi2(Fe4-xMnx)O10-δ complex oxides

    Kalita, Patricia E.; Cornelius, Andrew L.; Lipinska, Kristina E.; Lufaso, Michael W.; Kann, Zachary R.; Sinogeikin, Stanislav; Hemmers, Oliver A.; Schneider, Hartmut (N. Florida); (CIW); (UNLV); (Koln)

    2016-07-29

    Single phased mullite-type Bi2Fe4-xMnxO10-δ mixed crystals (0.25 ± x ± 3.125) and the end-member Bi2Fe4O9, synthesized from the oxides by reaction sintering up to 825°C, were studied at high-pressures in order to probe their high-pressure behavior and any possible structural phase transitions. In-situ synchrotron radiation-based powder X-ray diffraction was carried out in a diamond anvil cell, under quasi-hydrostatic conditions, up to a pressure of about 20 GPa at room temperature for each sample. A pressure-induced phase transition was found in all samples. The transition appeared spread over a pressure range and was not completed at the top investigated pressure. This is the first report of a pressure-induced phase transition in Bi2Fe4-xMnxO10-δ mixed crystals.

  6. Folic acid

    ... include leafy vegetables (such as spinach, broccoli, and lettuce), okra, asparagus, fruits (such as bananas, melons, and ... Pyrimethamine (Daraprim)Pyrimethamine (Daraprim) is used to treat parasite infections. Folic acid might decrease the effectiveness of ...

  7. Folic Acid

    Full Text Available ... March of Dimes Premature Birth Report Card Grades Cities, Counties; Focuses on Racial and Ethnic Disparities March ... your baby. Learn how you can get the right amout of folic acid before and during pregnancy ...

  8. ACID RAIN

    Acid precipitation has become one of the major environmental problems of this decade. It is a challenge to scientists throughout the world. Researchers from such diverse disciplines as plant pathology, soil science, bacteriology, meteorology and engineering are investigating diff...

  9. Folic Acid

    Full Text Available ... Just a moment, please. You've saved this page It's been added to your dashboard . Folic acid ... Map Premature birth report card Careers Archives Health Topics Pregnancy Before or between pregnancies Nutrition, weight & fitness ...

  10. Folic Acid

    Full Text Available ... Folic acid Description | Related videos | Most played video E-mail to a friend Please fill in all fields. Please enter a valid e-mail address. Your information: Your recipient's information: Your ...

  11. Effect of d-HDDR Process and Element Co on Magnetic Properties of Nd12.5Fe80.4-xCoxGa0.5Zr0.1B6.5 Alloys%d-HDDR工艺及合金元素Co对Nd12.5Fe80.4-xCoxGa0.5Zr0.1B6.5合金磁性能的影响

    赵康军; 付猛; 连法增; 陈志刚

    2008-01-01

    本文采用室温吸氢后"氢化一歧化一脱氢一再复合"(d-HDDR)工艺制备Nd12.5Fe80.4-xCoxGa0.5Zr0.1B6.5(x=0,4.0,8.0,12.0,15.0)各向异性永磁磁粉,研究了歧化氢压、歧化温度、再复合温度及合金元素Co的添加对Nd12.5Fe30.4-xCoxGa0.5Zr0.1B6.5合金磁性能的影响规律,并利用X射线衍射仪(XRD)对磁粉的微观结构进行了表征.结果表明,d-HDDR工艺制得的磁粉具有良好的磁性能,合金元索Co的添加可提高磁粉的磁性能.制得磁粉的典型性能为:Br=1.252T,jHc=768.7kA/m,(BH)max=253.4kJ/m3,DOA=0.58.

  12. Fluorination of La2−xSrxCuO4 (x = 0, 0.15, 0.3) and study on the crystal structures, magnetic properties of their fluorinated products

    Highlights: • Fluorination of La2−xSrxCuO4 (x = 0, 0.15, 0.3) by ZnF2 with few byproducts. • Less of impurities are benefit to research its structure and properties. • Suffering a phase transformation and unit cell expansion after fluorination. • Determining chemical formula and fluorine ions occupation of fluorinated product. - Abstract: Here we report using the transition metal difluoride ZnF2 to fluorinate K2NiF4-type cuprates La2−xSrxCuO4 (x = 0, 1.5, 0.3). Unlike other fluorinating agents, the technique is nontoxic, easy to handle and the byproduct ZnO can be removed. After fluorination, the fluorinated product of La2CuO4 suffers a phase transformation and unit cell expansion. While La1.85Sr0.15CuO4 and La1.7Sr0.3CuO4 indicate no change in structure after fluorination, their space groups still are I/4mmm, however, their lattices become larger, too. We emphasis the structural characterizations for fluorinated product of La1.7Sr0.3CuO4 by high-resolution transmission electron microscopy (HRTEM) images and electron diffraction (ED) patterns. Moreover, we determine the chemical formula to be La1.54Sr0.46CuO3.1F0.9 and the fluorine ions are prone to be located in the apical sites of the Cu(O, F)6 octahedron in the structure of post-treated fluorinated product of La1.7Sr0.3CuO4. Magnetization investigations demonstrate that partial replacement of the lanthanum by strontium changes the magnetism of post-treated fluorinated products of La2−xSrxCuO4 (x = 0, 0.15, 0.3) and they exhibit a paramagnetic behavior

  13. Electrochemical properties of nanocrystalline LiCu{sub x}Mn{sub 2-x}O{sub 4} (x = 0.2-0.6) particles prepared by ultrasonic spray pyrolysis method

    Ebin, Burcak [Metallurgical and Materials Engineering Department, Istanbul Technical University, Ayazaga Campus, Sar Latin-Small-Letter-Dotless-I yer, 34469 Istanbul (Turkey); Guermen, Sebahattin, E-mail: gurmen@itu.edu.tr [Metallurgical and Materials Engineering Department, Istanbul Technical University, Ayazaga Campus, Sar Latin-Small-Letter-Dotless-I yer, 34469 Istanbul (Turkey); Lindbergh, Goeran [Department of Chemical Engineering and Technology, Applied Electrochemistry, Royal Institute of Technology, KTH, SE-100 44 Stockholm (Sweden)

    2012-10-15

    The nanocrystalline LiCu{sub x}Mn{sub 2-x}O{sub 4} (x = 0.2-0.6) particles were prepared by ultrasonic spray pyrolysis method using lithium nitrate, manganese nitrate and copper nitrate salts at 800 Degree-Sign C in air atmosphere. Particle properties were characterized by X-ray diffraction, scanning electron microscopy, energy dispersive spectroscopy. Besides, voltammetric and galvanostatic tests were performed to investigate the effects of the copper substituted on electrochemical behavior. Particle characterization studies showed that low copper substituted nanocrystalline particles had single spinel structure, and increasing amount caused tendency of second spinel phase formation. Particles, ranging between 250 nm and 1.5 {mu}m size, were formed by aggregation of nanoparticles. The cumulative discharge capacities of LiCu{sub 0.2}Mn{sub 1.8}O{sub 4} were determined as 122, 105 and 87 mAh g{sup -1} at 0.5, 1 and 2 C rates, respectively between 4.8 and 3 V potential range. The capacity fade is 44% of initial capacity after 50 cycles at 0.5C rate. Results showed that electrochemical properties of LiCu{sub x}Mn{sub 2-x}O{sub 4} (x = 0.2-0.6) particles were impaired by increasing Cu substitute due to the second phase formation and ionic displacement in the lattice. -- Highlights: Black-Right-Pointing-Pointer Production of Cu substituted spinel LiMn{sub 2}O{sub 4} cathode particles by spray pyrolysis. Black-Right-Pointing-Pointer Effects of Cu amount to the spinel LiMn{sub 2}O{sub 4} structure. Black-Right-Pointing-Pointer Second spinel phase formation by increasing Cu substitute. Black-Right-Pointing-Pointer Increasing pores morphology by Cu substitute. Black-Right-Pointing-Pointer Electrochemical performance of LiCu{sub x}Mn{sub 2-x}O{sub 4} (x = 0.2, 0.4 and 0.6).

  14. In contrast to conventional inactivated influenza vaccines, 4xM2e.HSP70c fusion protein fully protected mice against lethal dose of H1, H3 and H9 influenza A isolates circulating in Iran

    Ebrahimi, Seyyed Mahmoud, E-mail: smebrahimi@shirazu.ac.ir [Applied Biotechnology Research Center, Baqiyatallah University of Medical Sciences, P.O. Box 14155-3651,Tehran (Iran, Islamic Republic of); Research Center of Virus and Vaccine, Baqiyatallah University of Medical Science, P.O.Box 14155-3651, Tehran (Iran, Islamic Republic of); Dabaghian, Mehran [Department of Pathobiology, University of Tehran, Faculty of Veterinary Medicine, P.O. Box 14155-6453, Tehran (Iran, Islamic Republic of); Tebianian, Majid [Department of Biotechnology, Razi Vaccine and Serum Research Institute (RVSRI), P.O. Box 31975/148, Karaj, Tehran (Iran, Islamic Republic of); Zabeh Jazi, Mohammad Hossein [Department of Pathobiology, University of Tehran, Faculty of Veterinary Medicine, P.O. Box 14155-6453, Tehran (Iran, Islamic Republic of)

    2012-08-15

    Ideal vaccines against influenza viruses should elicit not only a humoral response, but also a cellular response. Mycobacterium tuberculosis HSP70 (mHSP70) have been found to promote immunogenic APCs function, elicit a strong cytotoxic T lymphocyte (CTL) response, and prevent the induction of tolerance. Moreover, it showed linkage of antigens to the C-terminus of mHSP70 (mHSP70c) can represent them as vaccines resulted in more potent, protective antigen specific responses in the absence of adjuvants or complex formulations. Hence, recombinant fusion protein comprising C-terminus of mHSP70 genetically fused to four tandem repeats of the ectodomain of the conserved influenza matrix protein M2 (M2e) was expressed in Escherichia coli, purified under denaturing condition, refolding, and then confirmed by SDS-PAGE, respectively. The recombinant fusion protein, 4xM2e.HSP70c, retained its immunogenicity and displayed the protective epitope of M2e by ELISA and FITC assays. A prime-boost administration of 4xM2e.HSP70c formulated in F105 buffer by intramuscular route in mice (Balb/C) provided full protection against lethal dose of mouse-adapted H1N1, H3N2, or H9N2 influenza A isolates from Iran compared to 0-33.34% survival rate of challenged unimmunized and immunized mice with the currently in use conventional vaccines designated as control groups. However, protection induced by immunization with 4xM2e.HSP70c failed to prevent weight loss in challenged mice; they experienced significantly lower weight loss, clinical symptoms and higher lung viral clearance in comparison with protective effects of conventional influenza vaccines in challenged mice. These data demonstrate that C-terminal domain of mHSP70 can be a superior candidate to deliver the adjuvant function in M2e-based influenza A vaccine in order to provide significant protection against multiple influenza A virus strains.

  15. In contrast to conventional inactivated influenza vaccines, 4xM2e.HSP70c fusion protein fully protected mice against lethal dose of H1, H3 and H9 influenza A isolates circulating in Iran

    Ideal vaccines against influenza viruses should elicit not only a humoral response, but also a cellular response. Mycobacterium tuberculosis HSP70 (mHSP70) have been found to promote immunogenic APCs function, elicit a strong cytotoxic T lymphocyte (CTL) response, and prevent the induction of tolerance. Moreover, it showed linkage of antigens to the C-terminus of mHSP70 (mHSP70c) can represent them as vaccines resulted in more potent, protective antigen specific responses in the absence of adjuvants or complex formulations. Hence, recombinant fusion protein comprising C-terminus of mHSP70 genetically fused to four tandem repeats of the ectodomain of the conserved influenza matrix protein M2 (M2e) was expressed in Escherichia coli, purified under denaturing condition, refolding, and then confirmed by SDS–PAGE, respectively. The recombinant fusion protein, 4xM2e.HSP70c, retained its immunogenicity and displayed the protective epitope of M2e by ELISA and FITC assays. A prime-boost administration of 4xM2e.HSP70c formulated in F105 buffer by intramuscular route in mice (Balb/C) provided full protection against lethal dose of mouse-adapted H1N1, H3N2, or H9N2 influenza A isolates from Iran compared to 0–33.34% survival rate of challenged unimmunized and immunized mice with the currently in use conventional vaccines designated as control groups. However, protection induced by immunization with 4xM2e.HSP70c failed to prevent weight loss in challenged mice; they experienced significantly lower weight loss, clinical symptoms and higher lung viral clearance in comparison with protective effects of conventional influenza vaccines in challenged mice. These data demonstrate that C-terminal domain of mHSP70 can be a superior candidate to deliver the adjuvant function in M2e-based influenza A vaccine in order to provide significant protection against multiple influenza A virus strains.

  16. Fluorination of La{sub 2−x}Sr{sub x}CuO{sub 4} (x = 0, 0.15, 0.3) and study on the crystal structures, magnetic properties of their fluorinated products

    Chen, Xiuhua [Division of Nanomaterials and Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei 230026 (China); Tang, Kaibin, E-mail: kbtang@ustc.edu.cn [Division of Nanomaterials and Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei 230026 (China); Zeng, Suyuan [Shandong Provincial Key Laboratory of Chemical Energy Storage and Novel Cell Technology, Department of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059 (China); Hao, Qiaoyan; Wang, Dake; Gao, Zhan; Wang, Yan [Division of Nanomaterials and Chemistry, Hefei National Laboratory for Physical Sciences at the Microscale, Department of Chemistry, University of Science and Technology of China, Hefei 230026 (China)

    2015-03-25

    Highlights: • Fluorination of La{sub 2−x}Sr{sub x}CuO{sub 4} (x = 0, 0.15, 0.3) by ZnF{sub 2} with few byproducts. • Less of impurities are benefit to research its structure and properties. • Suffering a phase transformation and unit cell expansion after fluorination. • Determining chemical formula and fluorine ions occupation of fluorinated product. - Abstract: Here we report using the transition metal difluoride ZnF{sub 2} to fluorinate K{sub 2}NiF{sub 4}-type cuprates La{sub 2−x}Sr{sub x}CuO{sub 4} (x = 0, 1.5, 0.3). Unlike other fluorinating agents, the technique is nontoxic, easy to handle and the byproduct ZnO can be removed. After fluorination, the fluorinated product of La{sub 2}CuO{sub 4} suffers a phase transformation and unit cell expansion. While La{sub 1.85}Sr{sub 0.15}CuO{sub 4} and La{sub 1.7}Sr{sub 0.3}CuO{sub 4} indicate no change in structure after fluorination, their space groups still are I/4mmm, however, their lattices become larger, too. We emphasis the structural characterizations for fluorinated product of La{sub 1.7}Sr{sub 0.3}CuO{sub 4} by high-resolution transmission electron microscopy (HRTEM) images and electron diffraction (ED) patterns. Moreover, we determine the chemical formula to be La{sub 1.54}Sr{sub 0.46}CuO{sub 3.1}F{sub 0.9} and the fluorine ions are prone to be located in the apical sites of the Cu(O, F){sub 6} octahedron in the structure of post-treated fluorinated product of La{sub 1.7}Sr{sub 0.3}CuO{sub 4}. Magnetization investigations demonstrate that partial replacement of the lanthanum by strontium changes the magnetism of post-treated fluorinated products of La{sub 2−x}Sr{sub x}CuO{sub 4} (x = 0, 0.15, 0.3) and they exhibit a paramagnetic behavior.

  17. Okadaic acid

    Danielsen, E Michael; Hansen, Gert H; Severinsen, Mai C K

    2014-01-01

    Okadaic acid (OA) is a polyether fatty acid produced by marine dinoflagellates and the causative agent of diarrhetic shellfish poisoning. The effect of OA on apical endocytosis in the small intestine was studied in organ cultured porcine mucosal explants. Within 0.5-1 h of culture, the toxin caused...... endosomes (TWEEs) occurred unimpeded in the presence of OA, FM condensed in larger subapical structures by 1 h, implying a perturbed endosomal trafficking/maturation. The fluorescent lysosomotropic agent Lysotracker revealed induction of large lysosomal structures by OA. Endocytosis from the brush border...

  18. Scalar and spinor Casimir energies in even-dimensional Kaluza-Klein spaces of the form M4 x S/sup N/1 x S/sup N/2 x xxx

    We use two methods of computing the unique logarithmically divergent part of the Casimir energy for massive scalar and spinor fields defined on even-dimensional Kaluza-Klein spaces of the form M4 x S/sup N/1 x S/sup N/2 x xxx. Both methods (heat kernel and direct) give identical results. The first evaluates the required internal zeta function by identifying it in the asymptotic expansion of the trace of the heat kernel, and the second evaluates the zeta function directly using the Euler-Maclaurin sum formula. In Appendix C we tabulate these energies for all spaces of total internal dimension ≤6. These methods are easily applied to vector and tensor fields needed in computing one-loop vacuum gravitational energies on these spaces. Stable solutions are given for internal structure S2 x S2

  19. Spray-drying synthesized lithium-excess Li4+xTi5-xO12-δ and its electrochemical property as negative electrode material for Li-ion batteries

    Li4Ti5O12 (Fd-3m space group) materials were synthesized by controlling the lithium and titanium ratios (Li/Ti) in the range of 0.800-0.900 by using a spray-drying method, followed by calcination at several temperatures between 700 and 900 deg. C for large-scale production. Chemical and structure studies of the final products were done by X-ray diffraction (XRD), neutron diffraction (ND), X-ray photon electron spectroscopy (XPS), scanning electron microscopy (SEM) and inductively coupled plasma mass spectrometry (ICP-MS). The optimum synthesis condition was examined in relation to the electrochemical characteristics including charge-discharge cycling and ac impedance spectroscopy. It was found that when the spray-drying precursors at the Li/Ti ratio of 0.860 were calcined at 700-900 deg. C for 12 h in air, a pure Li4+xTi5-xO12-δ (x = 0.06-0.08) phase with a lithium-excess composition was obtained. Based on the structural studies, it was found that the excess lithium is located at the lithium and titanium layer of the 16d site in the spinel structure (Fd-3m). These pure Li4+xTi5-xO12-δ (x = 0.06-0.08) phase materials showed a higher discharge capacity of ∼164 mAh g-1 at 1.55 V (vs. Li/Li+), between the cut-off voltage of 1.2-3.0, with an excellent cyclability and superior rate performance in comparison with the Li4Ti5O12 phase containing impurity phases.

  20. Preparation and properties of the full series of cuboidal clusters [Mo(x)W4-xSe4(H2O)12]n+ (n = 4-6) and their derivatives.

    Sokolov, M; Esparza, P; Hernandez-Molina, R; Platas, J G; Mederos, A; Gavin, J A; Llusar, R; Vicent, C

    2005-02-21

    Hydrothermal reactions between incomplete cuboidal cluster aqua complexes [M3Q4(H2O)9]4+ and M(CO)6 (M = Mo, W; Q = S, Se) offer easy access to the corresponding cuboidal clusters M4Q4. The complete series of homometal and mixed Mo/W clusters [Mo(x)W4-xQ4(H2O)12]n+ (x = 0-4, n = 4-6) has been prepared. Upon oxidation of the mixed-metal clusters, it is the W atom which is lost, allowing selective preparation of new trinuclear clusters [Mo2WSe4(H2O)9]4+ and [MoW2Se4(H2O)9]4+. The aqua complexes were converted by ligand exchange reactions into dithiophosphato and thiocyanato complexes, and crystal structures of [W4S4((EtO)2PS2)6], [MoW3S4((EtO)2PS2)6], [Mo4Se4((EtO)2PS2)6], [W4Se4((i-PrO)2PS2)6], and (NH4)6[W4Se4(NCS)12]-4H20 were determined. Cyclic voltammetry was performed on [Mo(x)W4-xCO4(H2O)12]n+, showing reversible redox waves 6+/5+ and 5+/4+. The lower oxidation states are more difficult to access as the number of W atoms increases. The [Mo2WSe4(H2O)9]4+ and [MoW2Se4(H2O)9]4+ species were derivatized into [Mo2WSe4(acac)3(py)3]+ and [MoW2Se4(acac)3(py)3]+, which were also studied by CV. When appropriate, the products were also characterized by FAB-MS and NMR (31P, 1H) data. PMID:15859295

  1. Finite-size corrections in the SU(2)xSU(2) sector of type IIA string theory on AdS{sub 4}xCP{sup 3}

    Astolfi, Davide [Dipartimento di Fisica, Universita di Perugia, I.N.F.N. Sezione di Perugia, Via Pascoli, I-06123 Perugia (Italy)], E-mail: astolfi@pg.infn.it; Puletti, Valentina Giangreco M. [Department of Physics and Astronomy, Uppsala University, SE-75108 Uppsala (Sweden)], E-mail: valentina.giangreco@fysast.uu.se; Grignani, Gianluca [Dipartimento di Fisica, Universita di Perugia, I.N.F.N. Sezione di Perugia, Via Pascoli, I-06123 Perugia (Italy)], E-mail: gianluca.grignani@pg.infn.it; Harmark, Troels [Niels Bohr Institute, Blegdamsvej 17, 2100 Copenhagen O (Denmark)], E-mail: harmark@nbi.dk; Orselli, Marta [The Niels Bohr Institute, Blegdamsvej 17, 2100 Copenhagen O (Denmark)], E-mail: orselli@nbi.dk

    2009-03-21

    We consider finite-size corrections in the SU(2)xSU(2) sector of type IIA string theory on AdS{sub 4}xCP{sup 3}, which is the string dual of the recently constructed N=6 superconformal Chern-Simons theory of Aharony, Bergman, Jafferis and Maldacena (ABJM theory). The string states we consider are in the RxS{sup 2}xS{sup 2} subspace of AdS{sub 4}xCP{sup 3} with an angular momentum J on CP{sup 3} being large. We compute the finite-size corrections using two different methods, one is to consider curvature corrections to the Penrose limit giving an expansion in 1/J, the other by considering a low energy expansion in {lambda}'={lambda}/J{sup 2} of the string theory sigma-model, {lambda} being the 't Hooft coupling of the dual ABJM theory. For both methods there are interesting issues to deal with. In the near-pp-wave method there is a 1/{radical}(J) interaction term for which we use zeta-function regularization in order to compute the 1/J correction to the energy. For the low energy sigma-model expansion we have to take into account a non-trivial coupling to a non-dynamical transverse direction. We find agreement between the two methods. At order {lambda}' and {lambda}'{sup 2}, for small {lambda}', our results are analogous to the ones for the SU(2) sector in type IIB string theory on AdS{sub 5}xS{sup 5}. Instead at order {lambda}'{sup 3} there are interactions between the two two-spheres. We compare our results with the recently proposed all-loop Bethe ansatz of Gromov and Vieira and find agreement.

  2. Dentistry 4. X-ray diagnostics

    DIN pocketbook 267/4 gives an overview of the normative requirements of the new X-Ray and Radiation Protection Ordinance, which has been in effect since 1 November 2011. This DIN pocketbook is intended for anyone charged with professional responsibility for the use of ionizing radiation in dentistry, operators and users of x-ray devices, radiation protection officers, accredited experts, manufacturers as well as for anyone with an interest in radiation protection or optimal radiological diagnostics. It contains standards relating to the following areas: acceptance and constancy testing; devices for evaluating findings (monitors, film viewing devices), films, printers; archiving, designating, labelling. Adherence to the standards makes it possible to avoid distractive artefacts in x-ray images and optimise the quality of x-ray diagnostics in dentistry.

  3. Perfluorooctanoic acid

    P. de Voogt

    2014-01-01

    Perfluorooctanoic acid (PFOA, 335-67-1) is used in fluoropolymer production and firefighting foams and persists in the environment. Human exposure to PFOA is mostly through the diet. PFOA primarily affects the liver and can cause developmental and reproductive toxic effects in test animals.

  4. Ascorbic Acid

    Cevi-Bid® ... If you become pregnant while taking ascorbic acid, call your doctor. ... In case of overdose, call your local poison control center at 1-800-222-1222. If the victim has collapsed or is not breathing, call ...

  5. Stearic Acid

    Young, Jay A.

    2004-01-01

    A chemical laboratory information profile (CLIP) is presented for the chemical, stearic acid. The profile lists the chemical's physical and harmful characteristics, exposure limits, and symptoms of major exposure, for the benefit of teachers and students, who use the chemical in the laboratory.

  6. Mefenamic Acid

    Mefenamic acid comes as a capsule to take by mouth. It is usually taken with food every 6 hours as needed for up to 1 week. Follow ... pain vomit that is bloody or looks like coffee grounds black, tarry, or bloody stools slowed breathing ...

  7. Uptake and Dissolution of Gaseous Ethanol in Sulfuric Acid

    Michelsen, Rebecca R.; Staton, Sarah J. R.; Iraci, Laura T.

    2006-01-01

    The solubility of gas-phase ethanol (ethyl alcohol, CH3CH2OH, EtOH) in aqueous sulfuric acid solutions was measured in a Knudsen cell reactor over ranges of temperature (209-237 K) and acid composition (39-76 wt % H2SO4). Ethanol is very soluble under these conditions: effective Henry's law coefficients, H*, range from 4 x 10(exp 4) M/atm in the 227 K, 39 wt % acid to greater than 10(exp 7) M/atm in the 76 wt % acid. In 76 wt % sulfuric acid, ethanol solubility exceeds that which can be precisely determined using the Knudsen cell technique but falls in the range of 10(exp 7)-10(exp 10) M/atm. The equilibrium concentration of ethanol in upper tropospheric/lower stratospheric (UT/LS) sulfate particles is calculated from these measurements and compared to other small oxygenated organic compounds. Even if ethanol is a minor component in the gas phase, it may be a major constituent of the organic fraction in the particle phase. No evidence for the formation of ethyl hydrogen sulfate was found under our experimental conditions. While the protonation of ethanol does augment solubility at higher acidity, the primary reason H* increases with acidity is an increase in the solubility of molecular (i.e., neutral) ethanol.

  8. Synthesis and Characterisation of Addition Compounds of Pyridine Carboxylic Acid Hydrazides with Tin (IV) Halides, Organotin (IV) Halides and Thicyanates*

    R.C. Aggarwal; D.S.S. Vara Prasada Rao

    1981-01-01

    Addition compounds of the compositions SnX/sub 4/.xL and R/sub n/SnX/sub 4-n/.xL where X=Cl/sup -/, Br/sup -/, I/sup -/, or (NCS)/sup -/, R=phenyl or n-butyl, L = picolinic acid hydrazide (PH), nicotinic acid hydrazide (NH) or isonicotinic acide hydrazide (INH), x=1 or 2 and n= 1,2 or 3 have been prepared and characterised with the help of elemental analysis, molar conductance, UV and IR spectral studies. All the adducts are nonionic as evidenced from their low molar conductances in DMF. UV a...

  9. Hydroxycarboxylic acids and salts

    Kiely, Donald E; Hash, Kirk R; Kramer-Presta, Kylie; Smith, Tyler N

    2015-02-24

    Compositions which inhibit corrosion and alter the physical properties of concrete (admixtures) are prepared from salt mixtures of hydroxycarboxylic acids, carboxylic acids, and nitric acid. The salt mixtures are prepared by neutralizing acid product mixtures from the oxidation of polyols using nitric acid and oxygen as the oxidizing agents. Nitric acid is removed from the hydroxycarboxylic acids by evaporation and diffusion dialysis.

  10. Scheduled transplantation of bone marrow cells preincubated with acidic fibroblast growth factor (aFGF)

    Objective: To develop a new method of bone marrow scheduled transplantation (BMST) by making use of the effects of acidic fibroblast growth factor (aFGF) on improving hematopoiesis. Methods: The scheduled transplantation of bone marrow cells preincubated with aFGF (aFGF-BMST) was carried out to study the effects of aFGF on hematopoietic reconstitution and reducing acute graft versus host disease (GVHD) in acute radiation disease model of Kunming mice. Results: The survival rate of the group of aFGF-BMST mice with 4 x 106 BMXs was 40%, which was higher than the survival of the group of BMT with 1 x 107 BMCs alone (30%), but was lower than the survival of the group of BMST with 4 x 106 BMCs. On the other hand, the recovery rates in numbers of leucocytes, nucleated cells and CFU-E, CFU-GM, CFU-S were faster than those in the group of BMT with 1 x 107 BMCs alone and in the group of BMST with 4 x 106 BMCs. In addition, the severity of GVHD in the group of aFGF-BMST mice with 4 x 106 BMCs was lower than that in the group of BMT with 1 x 107 BMCs alone but was higher than that in the group of BMST with 4 x 106 BMCs. Conclusion: Although aFGF can activate heterogeneous T cells to cause GVHD, there is prospect of making full use of the effects of aFGF on improving hematopoiesis and reducing the side effects of aFGF leading to GVHD through scheduled transplantation of bone marrow cells preincubated with aFGF

  11. Voltammetric behaviour of uranium(VI) in sulfuric acid solutions containing pyridine

    It was shown that 8.8 x 10-5 to 4.4 x 10-3 M uranium(VI) solutions in sulfuric acid containing pyridine give a clearly defined cathodic peak with a height proportional to uranium(VI) concentration. Under the specified conditions, the electroreduction of uranium(VI) is irreversible and involves one electron, the limiting current of uranium(VI) is diffusion- and kinetically controlled. The kinetic parameters of the process under study were determined, and the effect of associated elements on the voltammetric behavior of uranium(VI) in pyridine-containing sulfuric acid supporting electrolytes was estimated

  12. Theoretical estimates of the anapole magnetizabilities of C{sub 4}H{sub 4}X{sub 2} cyclic molecules for X=O, S, Se, and Te

    Pagola, G. I.; Ferraro, M. B. [Departamento de Física, Facultad de Ciencias Exactas y Naturales, and IFIBA, CONICET, Universidad de Buenos Aires, Ciudad Universitaria, Pab. I, (1428) Buenos Aires (Argentina); Provasi, P. F. [Departamento de Física, Northeastern University, Av. Libertad 5500, W3400 AAS, Corrientes (Argentina); Pelloni, S.; Lazzeretti, P., E-mail: lazzeret@unimo.it [Dipartimento di Chimica, Università degli Studi di Modena e Reggio Emilia, via G. Campi 183, 41100 Modena (Italy)

    2014-09-07

    Calculations have been carried out for C{sub 4}H{sub 4}X{sub 2} cyclic molecules, with X=O, S, Se, and Te, characterized by the presence of magnetic-field induced toroidal electron currents and associated orbital anapole moments. The orbital anapole induced by a static nonuniform magnetic field B, with uniform curl C=∇×B, is rationalized via a second-rank anapole magnetizability tensor a{sub αβ}, defined as minus the second derivative of the second-order interaction energy with respect to the components C{sub α} and B{sub β}. The average anapole magnetizability a{sup ¯} equals −χ{sup ¯}, the pseudoscalar obtained by spatial averaging of the dipole-quadrupole magnetizability χ{sub α,βγ}. It has different sign for D and L enantiomeric systems and can therefore be used for chiral discrimination. Therefore, in an isotropic chiral medium, a homogeneous magnetic field induces an electronic anapole A{sub α}, having the same magnitude, but opposite sign, for two enantiomorphs.

  13. The Effects of Cd2+ Concentration on the Structure, Optical and Luminescence Properties of MgAl2O4:x% Cd2+ (0 < x ≤ 1.75) Nanophosphor Prepared by Sol-Gel Method

    Motloung, S. V.; Dejene, F. B.; Sithole, M. E.; Koao, L. F.; Ntwaeaborwa, O. M.; Swart, H. C.; Motaung, T. E.

    2016-06-01

    Cadmium-doped magnesium aluminate (MgAl2O4:x% Cd2+) powders with different cadmium concentrations (0 spinel structure. Cd2+ doping influenced crystallinity of the powder samples. The crystallite size and particle morphology were not affected by variation in the Cd2+ concentration. Ultraviolet-visible spectroscopy (UV-vis) measurements revealed that the band gap of the MgAl2O4 was influenced by Cd2+ doping. Un-doped and Cd2+-doped MgAl2O4 nanophosphors exhibited violet emission at 392 nm. There was no evidence of the emission peak shift, which suggested that all emissions originated from the defects within the host material. Increasing the Cd2+ concentration up-to 0.88 mol.% lead to luminescence intensity enhancement, while further increase of Cd2+ concentration lead to concentration quenching. The critical energy transfer distance (R c) between the neighbouring donors and acceptors was found to be 5.21 Å, suggesting that the multipole-multipole interaction (M-MI) is the major cause of concentration quenching. Commission Internationale de l'Elcairage (CIE) colour coordinates confirmed non-tuneable violet emission with intensity dependent on the Cd2+ concentration.

  14. Investigation of structural, magnetocaloric and electrical properties of La{sub 0.6}Ca{sub 0.4-x}Sr{sub x}MnO{sub 3} compounds

    Nasri, M., E-mail: marianasri@yahoo.fr [Laboratoire de Physique Appliquee, Faculte des Sciences, B.P. 1171, 3000 Sfax, Universite de Sfax (Tunisia); Triki, M.; Dhahri, E. [Laboratoire de Physique Appliquee, Faculte des Sciences, B.P. 1171, 3000 Sfax, Universite de Sfax (Tunisia); Hussein, M. [Physics Department, Rabigh College of Science and Art, King Abdulaziz University, P.O. Box 344, Rabigh 21911 (Saudi Arabia); Lachkar, P. [MCBT, Institut Neel, CNRS-25 avenue des Martyrs, batiment E, BP 166, 38042 Grenoble cedex 9 (France); Hlil, E.K. [Institut Neel, CNRS-Universite J. Fourier, BP 166, 38042 Grenoble (France)

    2013-01-01

    The La{sub 0.6}Ca{sub 0.4-x}Sr{sub x}MnO{sub 3} (x=0, 0.2 and 0.4) samples have been elaborated by the solid-state method. X-ray powder diffraction shows that, for x=0, the sample crystallizes in orthorhombic phase, while, for x{>=}0.2 the structure becomes rhombohedral. The variation of magnetization as a function of temperature and applied magnetic field were carried out. All samples exhibit a PM-FM transition at the Curie temperature T{sub C} which increases with Sr{sup 2+} content. Magnetocaloric effect has been calculated in terms of isothermal magnetic entropy change. A large magnetocaloric effect has been observed in all samples, the maximum entropy change, |{Delta}S{sub M}{sup max}|, reaches the highest value of 6.70 J/kg K under a magnetic field change of 5 T with an RCP value of 285 J/kg for La{sub 0.6}Ca{sub 0.2}Sr{sub 0.2}MnO{sub 3} composition, which will be an interesting compound for application materials working as magnetic refrigerants near room temperature. The electrical transport behavior {rho}(T) was also investigated. All the specimens undergo a metallic-semiconductor transition at the temperature T{sub {rho}}. The {rho}-T fit well with the phenomenological equation for conductivity under a percolation approach.

  15. Microstructure and Microwave Dielectric Properties of (1-x)MgAl2O4-x(Ca0.8Sr0.2)TiO3 Ceramics

    Huang, Yafei; Yu, Jun; Shen, Chunying; Tang, Mingliang

    2016-06-01

    The microwave dielectric properties of the (1-x)MgAl2O4-x(Ca0.8Sr0.2)TiO3 (x = 0.02 to 0.10) ceramic system synthesized by the traditional solid-state reaction method have been investigated. Spinel-structured MgAl2O4 was present together with perovskite-structured (Ca0.8Sr0.2)TiO3, and this multiphase system was verified by x-ray diffraction (XRD) and energy spectrum analyses throughout the whole compositional range. With increasing x, the temperature coefficient of resonant frequency (τ f) and permittivity (ɛ r) gradually increased. Consequently, near-zero τ f could be obtained for samples with x = 0.08. Excellent microwave dielectric properties with relative permittivity (ɛ r) of 10.92, quality factor (Q × f) of 52,563 GHz (at 12.9 GHz), and temperature coefficient of resonant frequency (τ f) of -5.6 ppm/°C were obtained for 0.92MgAl2O4-0.08(Ca0.8Sr0.2)TiO3 composite sintered at 1440°C for 3 h, making this material a promising candidate for use in global communication satellites and radar detectors.

  16. Non-stoichiometric cobalt ferrite, Co{sub x}Fe{sub 3−x}O{sub 4} (x=1.0 to 2.0): Structural, magnetic and magnetoelastic properties

    Nlebedim, I.C., E-mail: nlebedim@iastate.edu [Ames Laboratory, US Department of Energy, Iowa State University, Ames, IA 50011 (United States); Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011 (United States); Moses, A.J. [Wolfson Centre for Magnetics, School of Engineering, Cardiff University, Cardiff, CF 243AA (United Kingdom); Jiles, D.C. [Ames Laboratory, US Department of Energy, Iowa State University, Ames, IA 50011 (United States); Department of Electrical and Computer Engineering, Iowa State University, Ames, IA 50011 (United States)

    2013-10-15

    This work discusses the changes in the structural, magnetic and magnetoelastic properties of Co{sub x}Fe{sub 3−x}O{sub 4} (x=1.0 to 2.0) due to variations in cation concentration and the presence of a secondary Co{sub 1−y}Fe{sub y}O phase. Non-stoichiometric cobalt ferrite samples used in this study were prepared via the ceramic method. Samples with x>1 possess two phases; a secondary rock salt Co{sub 1−y}Fe{sub y}O phase and a spinel cobalt ferrite phase with varying cation concentration. The sample x=1 has only the spinel phase. Increase in Co concentration resulted in a decrease in magnetization but an increase in coercivity. Magnetostrictive properties and magnetocrystalline anisotropy were also affected by deviation from stoichiometric composition. Results are discussed on the basis of the coexistence of Co{sup 3+}, Co{sup 2+} and Fe{sup 3+} in the spinel lattice of the samples and the influence of the secondary Co{sub 1−y}Fe{sub y}O phase on the overall properties.

  17. Structural and magnetic susceptibility characteristics of Mn{sub 1-x}Cu{sub x}Fe{sub 2}O{sub 4} (x = 0-0.4) nanoparticles synthesized by self-assembling confined media of reverse micelle

    Ghasemi, Ali, E-mail: ali13912001@yahoo.co [Materials Engineering Department, Malek Ashtar University of Technology, Shahin Shahr (Iran, Islamic Republic of); Ghasemi, Ebrahim [Department of Materials Science and Engineering, Islamic Azad University-Majlesi Branch, Majlesi Town (Iran, Islamic Republic of)

    2010-10-22

    Research highlights: {yields} There are several techniques including sol-gel and co-precipitation which could be employed in order to fabricate fine ferrite particles. However the drawback of the mentioned process is relatively high sintering temperature. {yields} To the best of our knowledge no studies on the preparation of Mn{sub 1-x}Cu{sub x}Fe{sub 2}O{sub 4} ferrite at a low temperature have been reported. With this view in mind, current interest is to make Mn{sub 1-x}Cu{sub x}Fe{sub 2}O{sub 4} ferrite nanoparticles using reverse micelle technique at a low temperature. {yields} Magnetic properties were evaluated and it is found that there is strong interaction between nanoparticles. - Abstract: Mn{sub 1-x}Cu{sub x}Fe{sub 2}O{sub 4} (x = 0-0.4) ferrite nanoparticles were prepared by reverse micelle process. X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) were employed to probe structural and magnetic properties of samples. The temperature dependence of blocking temperature was measured using Superconducting Quantum Interference Device (SQUID) and AC magnetic susceptibility. The phenomenological Neel-Brown and Vogel-Fulcher models were employed to distinguish between the interacting or non-interacting system. Results exhibited that there is strong interaction between fine particles.

  18. Structural and magnetic susceptibility characteristics of Mn1-xCuxFe2O4 (x = 0-0.4) nanoparticles synthesized by self-assembling confined media of reverse micelle

    Research highlights: → There are several techniques including sol-gel and co-precipitation which could be employed in order to fabricate fine ferrite particles. However the drawback of the mentioned process is relatively high sintering temperature. → To the best of our knowledge no studies on the preparation of Mn1-xCuxFe2O4 ferrite at a low temperature have been reported. With this view in mind, current interest is to make Mn1-xCuxFe2O4 ferrite nanoparticles using reverse micelle technique at a low temperature. → Magnetic properties were evaluated and it is found that there is strong interaction between nanoparticles. - Abstract: Mn1-xCuxFe2O4 (x = 0-0.4) ferrite nanoparticles were prepared by reverse micelle process. X-ray diffraction (XRD), transmission electron microscopy (TEM) and vibrating sample magnetometer (VSM) were employed to probe structural and magnetic properties of samples. The temperature dependence of blocking temperature was measured using Superconducting Quantum Interference Device (SQUID) and AC magnetic susceptibility. The phenomenological Neel-Brown and Vogel-Fulcher models were employed to distinguish between the interacting or non-interacting system. Results exhibited that there is strong interaction between fine particles.

  19. Speeds of sound in {(1 - x)CH4 + xN2} with x = (0.10001, 0.19999, and 0.5422) at temperatures between 170 K and 400 K and pressures up to 30 MPa

    The speed of sound in {(1 - x)CH4 + xN2} has been measured with a spherical acoustic resonator. Two mixtures with x = (0.10001 and 0.19999) were studied along isotherms at temperatures between 220 K and 400 K with pressures up to 20 MPa; a few additional measurements at p = (25 and 30) MPa are also reported. A third mixture with x = 0.5422 was studied along pseudo-isochores at amount-of-substance densities between 0.2 mol . dm-3 and 5 mol . dm-3. Corrections for molecular vibrational relaxation are discussed in detail and relaxation times are reported. The overall uncertainty of the measured speeds of sound is estimated to be not worse than ±0.02%, except for those measurements in the mixture with x = 0.5422 that lie along the pseduo-isochore at the highest amount-of-substance density. The results have been compared with the predictions of several equations of state used for natural gas systems

  20. Synthesis and luminescence characteristics of Li2Y4-xEux(WO4)7-y(MoO4)y red-emitting phosphor for white LED

    茹晶晶; 郭飞云; 陈建中

    2013-01-01

    Li2Y4-xEux(WO4)7-y(MoO4)y red-emitting phosphors were synthesized by solid state reaction and characterized by powder X-ray diffraction (XRD) and photoluminescence (PL) spectrum. The excitation spectra showed that the phosphors could be efficiently excited by near-UV light of 395 nm. When the relative molar ratio of Mo/W was 7:0, and the optimum doped concentration of Eu3+was 2.8 mol, the phosphor showed strong red emission lines at 615 nm corresponding to the forced electric dipole 5D0→7F2 transition of Eu3+. Compared with Na2Y2Eu2(MoO4)7 and K2Y2Eu2(MoO4)7, the fluorescence intensity of Li2Y1.2Eu2.8(MoO4)7 phosphor was the strongest. The CIE chromaticity coordinates of Li2Y1.2Eu2.8(MoO4)7 phosphor was calculated to be (0.66, 0.34).

  1. Electrical properties of Cu{sub 2}Zn(Sn{sub 1−x}Si{sub x})S{sub 4} (x = 0.1, x = 0.4) compounds for absorber materials in solar-cells

    Hamdi, M., E-mail: hamdymed@gmail.com [Laboratoire de l’état solide, Département de Physique, Faculté des Sciences de Sfax, Université de Sfax, B.P. 1171, 3000 Sfax (Tunisia); Institut des matériaux Jean Rouxel (IMN), Université de Nantes – CNRS, 2 rue de la Houssiniere, B.P. 32229, Nantes cedex 03 44322 (France); Chrif, B. [Laboratoire de Physiques des Matériaux et Nanomatériaux appliqués à l’environnement, Faculté des Sciences de Gabés, 6072 Gabés (Tunisia); Lafond, A. [Institut des matériaux Jean Rouxel (IMN), Université de Nantes – CNRS, 2 rue de la Houssiniere, B.P. 32229, Nantes cedex 03 44322 (France); Louati, B. [Laboratoire de l’état solide, Département de Physique, Faculté des Sciences de Sfax, Université de Sfax, B.P. 1171, 3000 Sfax (Tunisia); Guillot-Deudon, C. [Institut des matériaux Jean Rouxel (IMN), Université de Nantes – CNRS, 2 rue de la Houssiniere, B.P. 32229, Nantes cedex 03 44322 (France); Hlel, F. [Laboratoire de l’état solide, Département de Physique, Faculté des Sciences de Sfax, Université de Sfax, B.P. 1171, 3000 Sfax (Tunisia)

    2015-09-15

    Graphical abstract: Frequency dependence of Z′ and Z″ and equivalent circuit model. - Highlights: • An equivalent circuit model is proposed for both compounds. • The electrical conductivities are dominated by band conduction and NNH. • The conductivities are dominated by “variable range hopping” mechanism. • In both materials, the ac conductivity is dominated by CBH and NSPT mechanisms. - Abstract: The electrical properties of two compounds Cu{sub 2}Zn(Sn{sub 1−x}Si{sub x})S{sub 4} (x = 0.1, x = 0.4) derived from the family of Cu{sub 2}ZnSnS{sub 4} and Cu{sub 2}ZnSiS{sub 4} have been prepared via a ceramic route, were investigated by conductivity measurements in a temperature range of 80–300 K. Structural characterizations of the materials were performed by powder X-ray diffraction. It was found that at high temperatures (160–300 K), in the studied range, the electrical conductivity was dominated by band conduction and nearest-neighbor hopping (NNH). However, Mott law with the variable range hopping (VRH) mechanism is predominant in the low temperature region (80–160 K). Characteristic parameters describing conductivity, such as the characteristic temperature (T{sub 0}), hopping distance, average hopping energy, localization length and density of states were determined, and their values were discussed. These results are critical for understanding the behavior of solar cells based on polycrystalline CZTSiS absorber layers.

  2. Energy transfer relation of a novel Ce3+/Pr3+/Eu3+ co-doped Sr2.975−xLaxAlO4+xF1−x solid solution phosphor

    The photoluminescence properties and energy transfer of a new Ce3+/Pr3+/Eu3+ co-doped solid-solution composition of Sr2.975−xLaxAlO4+xF1−x (LSAF) phosphor are investigated. Upon doping Pr3+ into lattices of LSAF:Ce host, a shoulder emission peak is observed at about 620 nm, owing to the transition of 1D2 → 3H4. Addition of Eu3+ to LSAF:Ce3+, Pr3+ phosphor results in a sharp emission peaked at 675 nm for the 5D0 → 7F3 transition and an increase of the intensity of red emission for Pr3+ with increasing Eu3+ concentration. The pathways of energy transfer among Ce3+, Pr3+, and Eu3+ are proposed to be responsible for color addition of a red component to the primary yellow emission, enabling a potential adjustable color for blue excitable warm white. (condensed matter: electronic structure, electrical, magnetic, and optical properties)

  3. Coordination compounds of nitrates and sulfates of some metals with isonicotinic acid hydrazide

    The complexes M(No3)2x2HINA, MSO4x2HINA, Cu(NO3)2xHINA, and CuSO4xHINAx1, 5C2H5OH (where M=Co, Ni, Cu, Zn, Cd; HINA is hydrazide of isonicotinic acid) are obtained, their infrared (400-4000 cm-1) and Raman (50-4000 cm-1) spectra are studied. It is shown that HINA molecules in all compounds are bound with the metal by the nitrogen atoms of the amino group. In nickel, zink, and cadmium complexes the nitrogen atoms of the heterocycle are also bound with the central atom, thus forming tubazid bridges

  4. Understanding Acid Rain

    Damonte, Kathleen

    2004-01-01

    The term acid rain describes rain, snow, or fog that is more acidic than normal precipitation. To understand what acid rain is, it is first necessary to know what an acid is. Acids can be defined as substances that produce hydrogen ions (H+), when dissolved in water. Scientists indicate how acidic a substance is by a set of numbers called the pH…

  5. 歧化氢压对Nd12.5Fe80.4-xCoxGa0.5Zr0.1B6.5各向异性HDDR磁粉性能的影响%Effect of disproportionating hydrogen pressure on the magnetic anisotropy d-HDDR power of the Nd12.5Fe80.4-xCoxBZr0.1Ga0.5

    赵康军; 付猛; 尤俊华; 连法增; 陈志刚

    2008-01-01

    主要研究了d-HDDR工艺及添加合金元素Co对Nd12.5Fe80.4-xCoxGa0.5Zr0.1B6.5(x=0、4、8、12、15)合金磁性能的影响规律.结果表明,氢压是HDDR磁粉吸氢歧化产生磁各向异性的重要敏感因素,0.025MPa的歧化氢压对提高磁粉的各向异性具有最好的效果,磁能积达到:Br=1.252T,jHc=768.7kA/m,(BH)max=253.4kJ/m3,DOA=0.58.(合金元素Co的添加有益于HDDR磁粉磁性能改善,在0~15%(原子分数),随着Co含量增加d-HDDR磁粉的磁能积逐渐增大.

  6. Dehydroabietic acid

    Xiao-Ping Rao

    2009-10-01

    Full Text Available The title compound [systematic name: (1R,4aS,10aR-7-isopropyl-1,4a-dimethyl-1,2,3,4,4a,9,10,10a-octahydrophenanthrene-1-carboxylic acid], C20H28O2, has been isolated from disproportionated rosin which is obtained by isomerizing gum rosin with a Pd-C catalyst.. Two crystallographically independent molecules exist in the asymmetric unit. In each molecule, there are three six-membered rings, which adopt planar, half-chair and chair conformations. The two cyclohexane rings form a trans ring junction with the two methyl groups in axial positions. The crystal structure is stabilized by intermolecular O—H...O hydrogen bonds.

  7. Ascorbic acid monoglucoside as antioxidant and radioprotector

    Ascorbic acid monoglucoside (AsAG), a glucoside derivative of ascorbic acid, has been examined for its antioxidant and radioprotective abilities. AsAG neutralized 1, 1 diphenyl -2-picryl-hydrazyl (DPPH), a stable free radical in a concentration dependent manner thus indicating its antioxidant ability. AsAG protected mice liver tissues in vitro from peroxidative damage in lipids (measured as TBARS) resulting from 25Gy γ irradiation. It also protected plasmid pBR322 DNA from gamma-radiation induced strand breaks as evidenced from studies on agarose gel electrophoresis of the plasmid DNA after radiation exposure. Oral administration of AsAG to mice prior to whole body gamma radiation exposure (4Gy) resulted in a reduction of radiation induced lipid peroxides in the liver tissue indicating in vivo radiation protection of membranes. Pulse radiolysis studies indicated that AsAG offered radioprotection by scavenging free radicals. The rate constants for the reactions OH and N3 radicals with AsAG were determined to be 6.4 x 109 dm3 mol-1 s-1 and 2.3 x 109 dm3 mol-1 s-1, respectively at pH 7. It was observed that AsAG radicals undergo conjugation as the pH of the solution is raised to 11 in the case of a one-electron oxidation reaction. As the OH· radical adds to the ring, the conjugation effect starts appearing at pH 10. (author)

  8. Crystal structure and spontaneous polarization of Bi{sub 4-x}Nd{sub x}Ti{sub 3}O{sub 12} studied by using neutron powder diffraction data

    Jeon, Min Ku [Department of Chemical and Biomolecular Engineering (BK21 Graduate Program) and Center for Ultramicrochemical Process Systems, Korea Advanced Institute of Science and Technology, 373-1, Yuseong, Daejeon 305-701 (Korea, Republic of); Kim, Yong-Il [Korea Research Institute of Standards and Science, PO Box 102, Yuseong, Daejeon 305-600 (Korea, Republic of); Nahm, Seung-Hoon [Korea Research Institute of Standards and Science, PO Box 102, Yuseong, Daejeon 305-600 (Korea, Republic of); Sohn, Jung Min [Department of Chemical and Biomolecular Engineering (BK21 Graduate Program) and Center for Ultramicrochemical Process Systems, Korea Advanced Institute of Science and Technology, 373-1, Yuseong, Daejeon 305-701 (Korea, Republic of); Jung, Chang Hwa [Department of Chemical and Biomolecular Engineering (BK21 Graduate Program) and Center for Ultramicrochemical Process Systems, Korea Advanced Institute of Science and Technology, 373-1, Yuseong, Daejeon 305-701 (Korea, Republic of); Woo, Seong Ihl [Department of Chemical and Biomolecular Engineering (BK21 Graduate Program) and Center for Ultramicrochemical Process Systems, Korea Advanced Institute of Science and Technology, 373-1, Yuseong, Daejeon 305-701 (Korea, Republic of)

    2007-08-07

    Crystal structural parameters of Bi{sub 4-x}Nd{sub x}Ti{sub 3}O{sub 12} (BNT, x = 0.25, 0.5, 0.75 and 1.0) were determined by means of neutron powder diffraction and Rietveld analysis based on the monoclinic space group of B1a1. The a-axis has been found to shrink monotonically from 5.4475(8) to 5.4100(1) A with x increasing from 0 to 0.75. The orthorhombicity defined as 2(a-b)/(a+b) decreased with increasing x because the b-axis lattice parameter remained almost constant. The c-axis increases monotonically up to x = 0.75. The spontaneous polarization, which is oriented along the a-axis (P{sub s}//a), decreased from 35.4 to 28.3, 24.8 and 22.2 {mu}C cm{sup -2} with x increasing from 0 to 0.25, 0.5 and 0.75, respectively as calculated by using the refined structural parameters. Thus, the substitution of Nd for Bi has been found to cause a considerable structural relaxation. Bi{sub 3}Nd{sub 1}Ti{sub 3}O{sub 12} showed a considerably small a-lattice parameter of 5.4004 (1) A and a very small P{sub s} value of only 7.5 {mu}C cm{sup -2} indicating that its structure is orthorhombic or close to tetragonal.

  9. Photocatalytic degradation of methylene blue dye and magneto-optical studies of magnetically recyclable spinel NixMn1-xFe2O4 (x = 0.0-1.0) nanoparticles

    Mathubala, G.; Manikandan, A.; Arul Antony, S.; Ramar, P.

    2016-06-01

    Nickel doped spinel manganese ferrite (NixMn1-xFe2O4: x = 0.0-1.0) nanoparticles were prepared successfully by a superficial microwave irradiation technique using urea as the fuel. Powder X-ray diffraction (XRD) analysis was recognized the configuration of single phase spinel structure of NixMn1-xFe2O4. Debye Sherrer's formula was used to calculate the average crystallite size of the samples, which were found in the range of 15-20 nm. High resolution scanning electron microscopy (HR-SEM) was used to analyze the surface morphology of the samples, which showed the particle like-morphology with smaller agglomeration, and it was also confirmed by high resolution transmission electron microscopy (HR-TEM). Energy dispersive X-ray (EDX) analysis confirmed the elemental composition, which also evidence for the formation of single pure phase. Microwave heating method produced well crystalline nature of the products, which was confirmed by selected area electron diffraction (SAED) analysis. UV-Visible diffuse reflectance spectra (DRS) were used to calculate the energy band gap and the observed values are increased slightly from 2.05 eV to 2.44 eV with increasing the Ni-dapant. Magnetic characterization of the samples were analyzed by room temperature vibrating sample magnetometer (VSM) technique and the observed magnetization (Ms) values are decreased with increasing Ni content, due to the different magnetic moments of Mn2+ and Ni2+ cations. Photocatalytic degradation (PCD) of methylene blue dye was carried out by self designed photo-catalytic reactor. It was observed that PCD efficiency is increased with increase in concentration of Ni and the sample Ni0.6Mn0.4Fe2O4 shows better photocatalytic activity (96.73%) than other samples.

  10. Magnetic and magnetocaloric properties of Cu{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (x=0.6, 0.7, 0.8) ferrites

    Akhter, Shahida, E-mail: shahida212@yahoo.com [Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh); Paul, D.P. [Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh); Hoque, S.M. [Materials Science Division, Atomic Energy Centre, Dhaka 1000 (Bangladesh); Hakim, M.A. [Dept. of Glass and Ceramic Engineering, Bangladesh University of Engineering and Technology, Dhaka (Bangladesh); Hudl, M.; Mathieu, R.; Nordblad, P. [Solid State Physics, Dept. of Engineering Sciences, Uppsala University, Uppsala (Sweden)

    2014-10-01

    The effect of Zn substitution on the magnetic and magnetocaloric properties of Cu{sub 1−x}Zn{sub x}Fe{sub 2}O{sub 4} (x=0.6, 0.7, 0.8) ferrites over a wide temperature range has been investigated. The polycrystalline samples were synthesized using the solid-state reaction at sintering temperature 1050 °C (1323 K) for 2 h and has been characterized by SQUID magnetometry. Magnetization versus temperature showed that all samples exhibit a paramagnetic to ferromagnetic transition with decreasing temperature. The Curie temperature T{sub c} is found to decrease from 373 K for x=0.6 to 140 K for x=0.8 as well as the saturation magnetization M{sub s} which shifts from 100 to 44 emu/gm. The magnetocaloric effect was obtained by measuring a family of M–H curves at set temperature intervals and calculating the entropy change, ΔS for this system using the Maxwell relation. The ΔS of all samples increased with increasing applied field and showed a maximum around their respective T{sub c}. The entropy change (ΔS) decreased with increasing Zn content, whereas the relative cooling power (RCP) slightly increased. The large RCP and ΔS found in Zn substitution Cu–Zn ferrites will be interesting for magnetic refrigeration near room temperature. - Highlights: • Double sintering ceramic technique is used in preparation of samples. • SQUID magnetometry is used to measure magnetic and magnetocaloric properties. • Samples shows a paramagnetic to ferromagnetic transition with decreasing temperature. • The magnetic entropy change (ΔS) shows a maximum around their respective T{sub c}.

  11. MS-Xα calculation of the elastic electron scattering cross sections and x-ray absorption spectra of CX4 and SiX4 (X = H,F,Cl)

    Multiple scattering Xα bound state and continuum calculations are used to study low energy elastic electron scattering cross sections and pre-edge features in the x-ray absorption spectra (XAS) of (C,Si)X4, X = H,F,Cl. Maxima in the electron scattering cross section are predicted to occur at energies below 4 eV in the t2 channel for CF4, CCl4, SiH4, and SiCl4. These maxima can be assigned to final state orbitals which are bound in XAS and well localized in space and a quantitative correspondence of such scattering ''resonance'' energies and XAS energies may be obtained using the transition state approach. For CH4 and SiF4 even those bound state orbitals giving the greatest XAS intensity are very diffuse, being essentially of Rydberg character. Broad electron scattering maxima are found at energies above 4 eV in these molecules which cannot be directly associated with the bound state orbitals dominating the XAS. The results thus establish that low energy electron scattering resonances and pre-edge XAS are closely related only for orbitals bound and reasonably well localized in XAS. The MS-Xα results almost always reproduce experimental trends along the molecular series but quantitative discrepancies from experiment are sometimes substantial, particularly for the broad high energy scattering maxima in CH4. The narrow t2 resonance calculated for CF4 is found to vary greatly in position and intensity as the C--F distance is varied by small amounts but the stronger, broader t2 resonance in SiH4 is little affected by bond distance variation

  12. Retarded acid emulsion

    Fast, C.R.; Rixe, F.H.; Duffield, E.L. Jr.

    1972-08-01

    Compositions for use in acidizing hydrocarbon-bearing formations are described. Retarded acid emulsions of prolonged stability make it possible for the acid in this form to be displaced substantial distances out into the formation before becoming spent. The action of acid emulsions for use in acidizing hydrocarbon-bearing formations is prolonged by employing as the principal emulsifying agent an amine salt of dodecylbenzene sulfonic acid. Acid emulsions employing the amine salt of dodecylbenzene sulfonic acid exhibit greater stability than those employing the free acid. (8 claims)

  13. Optoelectronic properties of XIn{sub 2}S{sub 4} (X = Cd, Mg) thiospinels through highly accurate all-electron FP-LAPW method coupled with modified approximations

    Yousaf, Masood [Department of Physics, Ulsan National Institute of Science and Technology, Ulsan 689-798 (Korea, Republic of); Physics Department, Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor (Malaysia); Dalhatu, S.A. [Physics Department, Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor (Malaysia); Murtaza, G. [Department of Physics, Islamia College, Peshawar, KPK (Pakistan); Khenata, R. [Laboratoire de Physique Quantique et de Modélisation Mathématique (LPQ3M), Département de Technologie, Université de Mascara, 29000 Mascara (Algeria); Sajjad, M. [School of Electronic Engineering, Beijing University of Posts and Telecommunications, Beijing 100876 (China); Musa, A. [Physics Department, Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor (Malaysia); Rahnamaye Aliabad, H.A. [Department of Physics, Hakim Sabzevari University (Iran, Islamic Republic of); Saeed, M.A., E-mail: saeed@utm.my [Physics Department, Faculty of Science, Universiti Teknologi Malaysia, Skudai 81310, Johor (Malaysia)

    2015-03-15

    Highlights: • Highly accurate all-electron FP-LAPW+lo method is used. • New physical parameters are reported, important for the fabrication of optoelectronic devices. • A comparative study that involves FP-LAPW+lo method and modified approximations. • Computed band gap values have good agreement with the experimental values. • Optoelectronic results of fundamental importance can be utilized for the fabrication of devices. - Abstract: We report the structural, electronic and optical properties of the thiospinels XIn{sub 2}S{sub 4} (X = Cd, Mg), using highly accurate all-electron full potential linearized augmented plane wave plus local orbital method. In order to calculate the exchange and correlation energies, the method is coupled with modified techniques such as GGA+U and mBJ-GGA, which yield improved results as compared to the previous studies. GGA+SOC approximation is also used for the first time on these compounds to examine the spin orbit coupling effect on the band structure. From the analysis of the structural parameters, robust character is predicted for both materials. Energy band structures profiles are fairly the same for GGA, GGA+SOC, GGA+U and mBJ-GGA, confirming the indirect and direct band gap nature of CdIn{sub 2}S{sub 4} and MgIn{sub 2}S{sub 4} materials, respectively. We report the trend of band gap results as: (mBJ-GGA) > (GGA+U) > (GGA) > (GGA+SOC). Localized regions appearing in the valence bands for CdIn{sub 2}S{sub 4} tend to split up nearly by ≈1 eV in the case of GGA+SOC. Many new physical parameters are reported that can be important for the fabrication of optoelectronic devices. Optical spectra namely, dielectric function (DF), refractive index n(ω), extinction coefficient k(ω), reflectivity R(ω), optical conductivity σ(ω), absorption coefficient α(ω) and electron loss function are discussed. Optical’s absorption edge is noted to be 1.401 and 1.782 for CdIn{sub 2}S{sub 4} and MgIn{sub 2}S{sub 4}, respectively. The

  14. NMR espectroscopic parameters of HX and Si (Sn)X{sub 4} (X = H, F, Cl, Br and I) and SnBr{sub 4-n}I{sub n} model compounds

    Maldonado, Alejandro F.; Gimenez, Carlos A. [Physics Department, Natural and Exact Science Faculty, Northeastern University of Argentina and Institute of Modelling and Innovation on Technology, IMIT Avda Libertad 5460, W3404AAS Corrientes (Argentina); Aucar, Gustavo A., E-mail: gaa@unne.edu.ar [Physics Department, Natural and Exact Science Faculty, Northeastern University of Argentina and Institute of Modelling and Innovation on Technology, IMIT Avda Libertad 5460, W3404AAS Corrientes (Argentina)

    2012-02-20

    Graphical abstract: Optimized fully relativistic calculations of NMR J-couplings (HBr, HI), chemical shifts (Si, Sn) and absolute shielding for reference compounds of heavy atoms (Si, Sn) are given. Highlights: Black-Right-Pointing-Pointer In this article we show a procedure to get accurate NMR {sigma}{sup Ref} of Si and Sn. Black-Right-Pointing-Pointer Calculations of {sigma} on more than three heavy-atom-containing molecules are given. Black-Right-Pointing-Pointer Our results are closer to {delta}{sup exp} than previous calculations for SnX{sub 4} (X = H, Cl, Br, I). Black-Right-Pointing-Pointer Optimized basis sets were considered for full R and NR calculations of NMR J and {sigma}. Black-Right-Pointing-Pointer Relativistic effects enlarge electron correlation effects on J-couplings. - Abstract: The NMR spectroscopic parameters are largely influenced by relativistic effects. They are highly dependent on the electronic behavior inside the spatial regions occupied by nuclei. Full relativistic calculations of indirect nuclear spin-spin couplings at random phase level of approach (RPA) in the title compounds with reoptimized Dyall cVTZ basis sets are given. A comparison with the results of calculations with other basis sets that are mostly used within the non-relativistic (NR) domain is presented. We analyzed the dependence of that couplings with the speed of light over the whole range of values, from the full relativistic to the NR regimes. Within this last regime, calculations at the second-order level of approach (SOPPA) indicated that electron correlation effects may not be as important for nuclear magnetic shieldings, but they must be included with care for J-coupling calculations. From these calculations, we determined that relativity enlarges the electron correlation effects of the J-couplings of HBr and HI. Because the results of nuclear magnetic shielding calculations within polarization propagators at the RPA level were reliable, we were able to show a new

  15. Crystal structure and local structure of Mg(2-x)Pr(x)Ni4 (x = 0.6 and 1.0) deuteride using in situ neutron total scattering.

    Sakaki, K; Terashita, N; Kim, H; Proffen, T; Majzoub, E H; Tsunokake, S; Nakamura, Y; Akiba, E

    2013-06-17

    We studied crystal structure and local structure of Mg(2-x)Pr(x)Ni4 (x = 0.6 and 1.0) and their deuterides using in situ neutron total scattering and first-principles calculations. The total scattering data were analyzed using Rietveld refinement and pair distribution function analysis (PDF). The crystal structure of Mg(2-x)Pr(x)Ni4 before deuterium absorption was C15b in space group F43m. No difference between the crystal and local (PDF) structures was observed. The crystal structure of Mg1.0Pr1.0Ni4D(∼4) was found to be orthorhombic in space group Pmn2(1), with three deuterium occupation sites: PrNi3 and two types of bipyramidal Pr2MgNi2 that have a plane of symmetry composed of MgNi2. There is no significant difference between the crystal structure and the local structure of Mg1.0Pr1.0Ni4D(∼4). On the other hand, the average crystal structure of the Mg-rich Mg1.4Pr0.6Ni4D(∼3.6) was C15b with two deuterium occupation sites: PrNi3 and MgPrNi2 suggesting that the deuterium occupation shifts away from the Pr2MgNi2 bipyramid. First-principles relaxed structures also showed the shift of the hydrogen occupation site toward the Pr atom of the bipyramid, when induced by Mg substitution for the opposing Pr, resulting in hydrogen occupation in the MgPrNi2 tetrahedral site. The PDF pattern of Mg1.4Pr0.6Ni4D(∼3.6) cannot be refined below 7.2 Å in atomic distances using the C15b structure which was obtained from Rietveld refinement but can be done using an orthorhombic structure. It suggests that Mg1.4Pr0.6Ni4D(∼3.6) was locally distorted to the orthorhombic. PMID:23724781

  16. Plasma amino acids

    Amino acids blood test ... types of methods used to determine the individual amino acid levels in the blood. ... test is done to measure the level of amino acids in the blood. An increased level of a ...

  17. Acid Lipase Disease

    ... Enhancing Diversity Find People About NINDS NINDS Acid Lipase Disease Information Page Synonym(s): Cholesterol Ester Storage Disease, ... Related NINDS Publications and Information What is Acid Lipase Disease ? Acid lipase disease or deficiency occurs when ...

  18. POLYELEOSTEARIC ACID VESICLES

    LI Zichen; XIE Ximng; FAN Qinghua; FANG Yifei

    1992-01-01

    α-Eleostearic acid and β-eleostearic acid formed vesicles in aqueous medium when an ethanol solutionofeleostearic acid was injected rapidly into a vigorously vortexed aqueous phase. Formation of the vesicles was demonstrated by electron microscopic observation and bromothymol blue encapsulation experiments. Polymerizations of the eleostearic acids in the formed vesicles carried out by UV irradiation produced poly-α-eleostearic acid and poly-β-eleostearic acid vesicles.

  19. Acid distribution in phosphoric acid fuel cells

    Okae, I.; Seya, A.; Umemoto, M. [Fuji Electric Co., Ltd., Chiba (Japan)

    1996-12-31

    Electrolyte acid distribution among each component of a cell is determined by capillary force when the cell is not in operation, but the distribution under the current load conditions had not been clear so far. Since the loss of electrolyte acid during operation is inevitable, it is necessary to store enough amount of acid in every cell. But it must be under the level of which the acid disturbs the diffusion of reactive gases. Accordingly to know the actual acid distribution during operation in a cell is very important. In this report, we carried out experiments to clarify the distribution using small single cells.

  20. Crystal structure, oxidation state and magnetism of Sr{sub x}La{sub 2−x}Cu{sub 0.5}Ru{sub 0.5}O{sub 4} (x=1, 1.5)

    Lü, Minfeng, E-mail: m.f.lv@ciac.jl.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Deng, Xiaolong [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Waerenborgh, João C. [IST/ITN, Instituto Superior Técnico, Univ Técnica de Lisboa, CFMC-UL, EN 10, 2686-953 Sacavém (Portugal); Wu, Xiaojie [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China); Meng, Jian, E-mail: jmeng@ciac.jl.cn [State Key Laboratory of Rare Earth Resource Utilization, Changchun Institute of Applied Chemistry, Chinese Academy of Sciences, Changchun 130022 (China)

    2014-03-15

    Sr{sub x}La{sub 2−x}Cu{sub 0.5}Ru{sub 0.5}O{sub 4} (x=1, 1.5) oxides with K{sub 2}NiF{sub 4}-type structure were prepared by solid state reaction and characterized by powder X-ray diffraction, X-ray photoelectron spectroscopy, magnetic and electrical resistivity measurements. The SrLaCu{sub 0.5}Ru{sub 0.5}O{sub 4} phase was obtained for the first time with a negligible amount of impurities. The octahedral Cu/RuO{sub 6} units are more elongated in SrLaCu{sub 0.5}Ru{sub 0.5}O{sub 4} than in Sr{sub 1.5}La{sub 0.5}Cu{sub 0.5}Ru{sub 0.5}O{sub 4} indicating a greater extent of static Jahn–Teller distortion. XPS suggests that mixed ion pairs Ru{sup 5+}/Ru{sup 4+}↔Cu{sup +}/Cu{sup 2+} are present in SrLaCu{sub 0.5}Ru{sub 0.5}O{sub 4}, while Ru remains as Ru{sup 5+} and Cu as Cu{sup 2+} in Sr{sub 1.5}La{sub 0.5}Cu{sub 0.5}Ru{sub 0.5}O{sub 4}. Both samples show spin-glass behavior, which can be explained by competition between ferromagnetic and antiferromagnetic superexchange interactions. The negative Weiss temperature estimated for SrLaCu{sub 0.5}Ru{sub 0.5}O{sub 4}, −318 K, is significantly lower than −11.5 K deduced for Sr{sub 1.5}La{sub 0.5}Cu{sub 0.5}Ru{sub 0.5}O{sub 4} which may be related to the higher static Jahn–Teller distortion in the former oxide. -- Graphical abstract: SrLaCu{sub 0.5}Ru{sub 0.5}O{sub 4} with K{sub 2}NiF{sub 4}-type structure show a larger static Jahn–Teller distortion than Sr{sub 1.5}La{sub 0.5}Cu{sub 0.5}Ru{sub 0.5}O{sub 4}, which may be related to stronger antiferromagnetic superexchange interactions. Highlights: • SrLaCu{sub 0.5}Ru{sub 0.5}O{sub 4} (I) larger Jahn–Teller (J–T) distortion than Sr{sub 1.5}La{sub 0.5}Cu{sub 0.5}Ru{sub 0.5}O{sub 4} (II). • Octahedral Cu/RuO{sub 6} units are more elongated in I than in II. • Mixed ion pairs Ru{sup 5+}/Ru{sup 4+}↔Cu{sup +}/Cu{sup 2+} are present in I, while Ru remains as Ru{sup 5+} and Cu as Cu{sup 2+} in II. • Negative Weiss temperature of I significantly lower

  1. Path Analysis on Organic Acids and Acidity of Loquat Fruit%枇杷果实酸度的通径分析

    祁芳斌; 陈发兴; 赖钟雄

    2012-01-01

    对枇杷果实中有机酸组分与酸度(可滴定酸)进行了通径分析.结果表明:苹果酸含量对酸度的贡献率最大,通径系数Px1→Y=0.613 9;异柠檬酸通过对苹果酸的影响(Px4→x1→r=0.446 0)而引起果实酸度的改变作用;异柠檬酸含量直接作用(Px4→Y=0.324 8);奎尼酸含量对酸度的影响并不明显.富马酸含量对酸度是负贡献,但它对酸度的直接通径系数(Px6=-0.062 0)的绝对值小于剩余通径系数(P6=0.174 4),对酸度影响作用很小.%The correlation between organic acid components and their titratable acidity of loquat fruits were studied with path analysis. Results showed that the content of malic acid among fruit organic acids was the greatest contributor to the titratable acidity with path coefficient of PX1-Y= 0. 613 9, followed by isocitrate with indirectly effecting in titratable acidity through malic acid (Px4-x1-y = 0.446 0), and then its directly influencing in fruit acidity (Px4-y = 0. 324 8). The correlation between quinate content and fruit acidity was not obvious. The negative path coefficient from fumarate acid concentration (Px6 -Y = -0. 062 0) indicated its small but negative contribution to fruit acidity.

  2. Acid Thunder: Acid Rain and Ancient Mesoamerica

    Kahl, Jonathan D. W.; Berg, Craig A.

    2006-01-01

    Much of Mesoamerica's rich cultural heritage is slowly eroding because of acid rain. Just as water dissolves an Alka-Seltzer tablet, acid rain erodes the limestone surfaces of Mexican archaeological sites at a rate of about one-half millimeter per century (Bravo et al. 2003). A half-millimeter may not seem like much, but at this pace, a few…

  3. Crystal structures of the Ln4-xIn 5-yS 13 ( Ln=La, Ce, Pr and Nd; x=0.08-0.12, y=0.21-0.24), La 3In 1.67S 7, Gd 3InS 6 and La 4Ag 2In 4S 13 compounds

    Gulay, L. D.; Daszkiewicz, M.; Huch, M. R.

    2008-10-01

    The orthorhombic crystal structures of the series of Ln 4-xIn 5-yS 13 ( Ln=La, Ce, Pr and Nd; x=0.08-0.12, y=0.21-0.24) compounds were investigated by means of X-ray crystal diffraction. The crystals of La 3In 1.67S 7 and Gd 3InS 6 were also obtained unexpectedly from the La-In-S and Gd-In-S systems and no respective Gd 4-xIn 5-yS 13 was obtained. In the structures of the orthorhombic Ln4-xIn 5-yS 13 series and hexagonal La 3In 1.67S 7 indium atoms occupy disordered positions in the octahedral and trigonal antiprismatic arrangement of the sulphur atoms. The crystal structure of the La 4Ag 2In 4S 13 is also given and discussed as an example of quaternary sulphide related to a ternary La-In sulphide.

  4. The radiation chemistry of connective tissue; hyaluronic acid

    Aqueous solutions of hyaluronic acid have been irradiated under various conditions and the amount of strand scission was determined viscometrically. OH radicals were found to be some 1.5 times more potent than H atoms at inducing breaks, methanol, propan-2-ol and t-butanol radicals produced relatively little breakage (potency less than 3% that of .OH). Tetranitromethane (TNM) has been used to measure the yield of reducing radicals produced on OH radical attack on hyaluronic acid, around 80% of the hyaluronic acid radicals reacted with TNM (i.e. are reducing radicals) with a rate constant of 4.5x108 mol-1 dm3 s-1. In contrast similar measurements on the polysaccharide model, β-cyclodextrin, indicated that all the radicals formed were reducing. The presence of TNM or oxygen during radiolysis caused a 30% fall in chain breakage. The majority of radicals produced in both hyaluronic acid and β-cyclodextrin are either 1,2 dihydroxy or 1-hydroxy 2-alkoxy type radicals, both of which form β-carbonyl radicals by the acid (and base) catalysed elimination of water or alcohol. These β-carbonyl radicals are considerably less reducing than their parent α-hydroxy radicals and are not expected to react with TNM. By determining the extent of reaction with TNM as a function of TNM concentration, the first order rate constant for the formation of the β-carbonyl radicals can be calculated on applying simple competition kinetics. The rate constant at pH 4 was found to be about 4x103 s-1 in the case of hyaluronic acid radicals, with the β-cyclodextrin system even at pH 2.8 the rate constant was less than 2x103 s-1. (author). 12 refs, 1 fig., 1 tab

  5. Acid Deposition Phenomena

    Acid deposition, commonly known as acid rain, occurs when emissions from the combustion of fossil fuels and other industrial processes undergo complex chemical reactions in the atmosphere and fall to the earth as wet deposition (rain, snow, cloud, fog) or dry deposition (dry particles, gas). Rain and snow are already naturally acidic, but are only considered problematic when less than a ph of 5.0 The main chemical precursors leading to acidic conditions are atmospheric concentrations of sulfur dioxide (SO2) and nitrogen oxides (NOx). When these two compounds react with water, oxygen, and sunlight in the atmosphere, the result is sulfuric (H2SO4) and nitric acids (HNO3), the primary agents of acid deposition which mainly produced from the combustion of fossil fuel and from petroleum refinery. Airborne chemicals can travel long distances from their sources and can therefore affect ecosystems over broad regional scales and in locations far from the sources of emissions. According to the concern of petroleum ministry with the environment and occupational health, in this paper we will discussed the acid deposition phenomena through the following: Types of acidic deposition and its components in the atmosphere Natural and man-made sources of compounds causing the acidic deposition. Chemical reactions causing the acidic deposition phenomenon in the atmosphere. Factors affecting level of acidic deposition in the atmosphere. Impact of acid deposition. Procedures for acidic deposition control in petroleum industry

  6. Measurements of the acid-binding capacity of ingredients used in pig diets

    Lawlor Peadar G

    2005-08-01

    Full Text Available Some feed ingredients bind more acid in the stomach than others and for this reason may be best omitted from pig starter foods if gastric acidity is to be promoted. The objective of this study was to measure the acid-binding capacity (ABC of ingredients commonly used in pig starter foods. Ingredients were categorised as follows: (i milk products (n = 6, (ii cereals (n = 10, (iii root and pulp products (n = 5, (iv vegetable proteins (n = 11, (v meat and fish meal (n = 2, (vi medication (n = 3, (vii amino acids (n = 4, (viii minerals (n = 16, (ix acid salts (n = 4, (x acids (n = 10. A 0.5 g sample of food was suspended in 50 ml distilled de-ionised water with continuous stirring. This suspension was titrated with 0.1 mol/L HCl or 0.1 mol/L NaOH so that approximately 10 additions of titrant was required to reach pH 3.0. The pH readings after each addition were recorded following equilibration for three minutes. ABC was calculated as the amount of acid in milliequivalents (meq required to lower the pH of 1 kg food to (a pH 4.0 (ABC-4 and (b pH 3.0 (ABC-3. Categories of food had significantly different (P

  7. Omega-6 Fatty Acids

    ... Some types are found in vegetable oils, including corn, evening primrose seed, safflower, and soybean oils. Other ... ACIDS are as follows:Improving mental development or growth in infants. Adding arachidonic acid (an omega-6 ...

  8. Zoledronic Acid Injection

    ... experience a reaction during the first few days after you receive a dose of zoledronic acid injection. Symptoms ... symptoms may begin during the first 3 days after you receive a dose of zoledronic acid injection and ...

  9. Catalytic Synthesis Lactobionic Acid

    V.G. Borodina

    2014-07-01

    Full Text Available Gold nanoparticles are obtained, characterized and deposited on the carrier. Conducted catalytic synthesis of lactobionic acid from lactose. Received lactobionic acid identify on the IR spectrum.

  10. Plasma amino acids

    Plasma amino acids is a screening test done on infants that looks at the amounts of amino ... Laboratory error High or low amounts of individual plasma amino acids must be considered with other information. ...

  11. Omega-3 Fatty Acids

    Omega-3 fatty acids are used together with lifestyle changes (diet, weight-loss, exercise) to reduce the amount ... the blood in people with very high triglycerides. Omega-3 fatty acids are in a class of medications ...

  12. The Acid Rain Reader.

    Stubbs, Harriett S.; And Others

    A topic which is often not sufficiently dealt with in elementary school textbooks is acid rain. This student text is designed to supplement classroom materials on the topic. Discussed are: (1) "Rain"; (2) "Water Cycle"; (3) "Fossil Fuels"; (4) "Air Pollution"; (5) "Superstacks"; (6) "Acid/Neutral/Bases"; (7) "pH Scale"; (8) "Acid Rain"; (9)…

  13. Acid Rain Study Guide.

    Hunger, Carolyn; And Others

    Acid rain is a complex, worldwide environmental problem. This study guide is intended to aid teachers of grades 4-12 to help their students understand what acid rain is, why it is a problem, and what possible solutions exist. The document contains specific sections on: (1) the various terms used in conjunction with acid rain (such as acid…

  14. Immunoglobulin and fatty acids

    2009-01-01

    The present invention relates to a composition comprising 0.1-10 w/w % immunoglobulin (Ig), 4-14 w/w % saturated fatty acids, 4-14 w/w % mono-unsaturated fatty acids and 0-5 w/w % poly-unsaturated fatty acids, wherein the weight percentages are based on the content of dry matter in the composition...

  15. Distribution and identification of Plutonium(IV) species in tri-n-butyl phosphate/HNO3 extraction system containing acetohydroxamic acid

    There was a significant research progress achieved with the aim to modify conventional PUREX process by stripping of plutonium from the tri-n-butyl phosphate (TBP) extraction product in the form of non-extractable complexes upon addition of back-hold complexation agents. The present paper reports effects of such salt-free complexant, acetohydroxamic acid (HAHA), on distribution ratio of Pu(IV) under wide concentration of nitric acid and additional nitrate. General formula of plutonium species present in the organic phase can be described as Pu(OH)x(AHA)y(NO3)4-x-y x 2TBP x wHNO3. (author)

  16. Cleavage of nucleic acids

    Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor L. (Madison, WI); Brow, Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

    2007-12-11

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  17. Cleavage of nucleic acids

    Prudent, James R. (Madison, WI); Hall, Jeff G. (Waunakee, WI); Lyamichev, Victor I. (Madison, WI); Brow; Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

    2010-11-09

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  18. Nucleic acid detection compositions

    Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor I. (Madison, WI); Brow, Mary Ann (Madison, WI); Dahlberg, James L. (Madison, WI)

    2008-08-05

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  19. Nucleic acid detection assays

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann; Dahlberg, James E.

    2005-04-05

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  20. Cleavage of nucleic acids

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann D.; Dahlberg, James E.

    2000-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  1. Acidizing carbonate reservoirs with chlorocarboxylic acid salt solutions

    Richardson, E.A.; Scheuerman, R.F.; Templeton, C.C.

    1978-10-31

    A carbonate reservoir is acidized slowly by injecting an aqueous solution of a chlorocarboxylic acid salt so that the rate of the acidization is limited to the rate at which an acid is formed by the hydrolyzing of the chlorocarboxylate ions. The rate at which a chlorocarboxylic acid salt hydrolyzes to form an acid provides the desired rate of acid-release. A more complete acid-base reaction by chloroacetic acid, as compared to formic, acetic, and proprionic, is due to its being a much stronger acid. The pKa of chloroacetic acid is 2.86, whereas that of formic acid is 3.75, and that of acetic acid is 4.75. The pKa of a solution of a weak acid is the pH exhibited when the concentration of undissociated acid equals the concentration of the acid anion. 14 claims.

  2. Nucleic acid detection kits

    Hall, Jeff G.; Lyamichev, Victor I.; Mast, Andrea L.; Brow, Mary Ann; Kwiatkowski, Robert W.; Vavra, Stephanie H.

    2005-03-29

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof. The present invention further relates to methods and devices for the separation of nucleic acid molecules based on charge. The present invention also provides methods for the detection of non-target cleavage products via the formation of a complete and activated protein binding region. The invention further provides sensitive and specific methods for the detection of nucleic acid from various viruses in a sample.

  3. Acidic Ionic Liquids.

    Amarasekara, Ananda S

    2016-05-25

    Ionic liquid with acidic properties is an important branch in the wide ionic liquid field and the aim of this article is to cover all aspects of these acidic ionic liquids, especially focusing on the developments in the last four years. The structural diversity and synthesis of acidic ionic liquids are discussed in the introduction sections of this review. In addition, an unambiguous classification system for various types of acidic ionic liquids is presented in the introduction. The physical properties including acidity, thermo-physical properties, ionic conductivity, spectroscopy, and computational studies on acidic ionic liquids are covered in the next sections. The final section provides a comprehensive review on applications of acidic ionic liquids in a wide array of fields including catalysis, CO2 fixation, ionogel, electrolyte, fuel-cell, membrane, biomass processing, biodiesel synthesis, desulfurization of gasoline/diesel, metal processing, and metal electrodeposition. PMID:27175515

  4. Electrochemical performance of LiFe(1-x)MnxPO4 (x = 0, 0.10, 0.15, 0.2) synthesized by solid state process as cathode material for Li-ion battery

    Triwibowo, J.; Priyono, S.; Purawiardi, R. I.; Ratri, C. R.; Suwandi, E.

    2016-02-01

    Mn-doped LiFePO4 was synthesized through solid state process. Starting materials as LiOH.2H2O, Fe2O3, MnO2, H3PO4 and citric acid were technical grade materials. Synthesis process was conducted in two step heating process. The first heating process was purposed to remove organic materials at temperature of 320 °C for 10 hours in inert atmosphere. Subsequently, the second heating process was conducted at 800 °C for 8 hours also in inert atmosphere. Obtained phase was further observed by means of XRD. Morphology of the obtained powder was analyzed by SEM. The electrochemical performance was observed by cyclic voltammetry with the potential range 2 - 4.2 V under the scan rate mV/s. The rate capability of the obtained material was determined by charge-discharge test under various C-rates (0.5-10C) for potential range of 2 - 4.2 V.

  5. Microorganisms for producing organic acids

    Pfleger, Brian Frederick; Begemann, Matthew Brett

    2014-09-30

    Organic acid-producing microorganisms and methods of using same. The organic acid-producing microorganisms comprise modifications that reduce or ablate AcsA activity or AcsA homolog activity. The modifications increase tolerance of the microorganisms to such organic acids as 3-hydroxypropionic acid, acrylic acid, propionic acid, lactic acid, and others. Further modifications to the microorganisms increase production of such organic acids as 3-hydroxypropionic acid, lactate, and others. Methods of producing such organic acids as 3-hydroxypropionic acid, lactate, and others with the modified microorganisms are provided. Methods of using acsA or homologs thereof as counter-selectable markers are also provided.

  6. Electrocatalytic oxidation of formic acid at an ordered intermetallic PtBi surface.

    Casado-Rivera, Emerilis; Gál, Zoltán; Angelo, A C D; Lind, Cora; DiSalvo, Francis J; Abruña, Héctor D

    2003-02-17

    The electrocatalytic oxidation of formic acid at a PtBi ordered intermetallic electrode surface has been investigated using cyclic voltammetry, rotating disk electrode (RDE) voltammetry and differential electrochemical mass spectrometry (DEMS). The results are compared to those at a polycrystalline platinum electrode surface. The PtBi electrode exhibits superior properties when compared to polycrystalline platinum in terms of oxidation onset potential, current density, and a much diminished poisoning effect by CO. Using the RDE technique, a value of 1.4 x 10(-4) cm s-1 was obtained for the heterogeneous charge transfer rate constant. The PtBi surface did not appear to be poisoned when exposed to a CO saturated solution for periods exceeding 0.5 h. The results for PtBi are discussed within the framework of the dual-path mechanism for the electrocatalytic oxidation of formic acid, which involves formation of a reactive intermediate and a poisoning pathway. PMID:12619419

  7. Radiation-chemical behaviour of Rh(3) in perchloric and nitric acid media

    Rhodium(3) behaviour in solutions of concentrated (> 1 mol/l) nitric and perchloric acids under 60Co gamma radiation with dose rate of 3.5 Gy/s has been studied. It is shown that in case of nitrate solution irradiation by doses up to 2x104 Gy, rhodium(3) concentration does not change. Rhodium(3) proved to be stable in perchlorate solutions in case of irradiation by doses up to 3x104 Gy; however, in the presence of organic acids and alcohols its reduction to methane occurred. Kinetic characteristics of rhodium(3) reduction by ethyl alcohol by the doses up to 4x104 Gy have been ascertained, reduction mechanism being considered. 6 refs.; 4 figs.; 1 tab

  8. Synthesis and proton conducting properties of zirconia bridged hydrocarbon/phosphotungstic acid hybrid materials

    Kim, Je-Deok; Honma, Itaru

    2004-08-15

    Recently, the organic/inorganic hybrid materials with flexibility, thermal, and chemical stabilities are extensively studied for the application of temperature tolerant polymer electrolyte fuel cells. This paper reports the preparation and properties of sol-gel derived proton conducting organic/inorganic materials based on zirconia bridged hydrocarbon phosphotungstic acids. The materials are molecular hybrids where linear hydrocarbons such as trimethylene glycols (TMGs) or octamethylene glycols (OMGs) are covalently bonded to zirconia interface to form macromolecular organic/inorganic networks. The hybrid materials become proton conducting polymer electrolytes by the addition of 12-phosphotungstic acids. The hybrid materials showed high thermal stability, and high protonic conductivity of 4x10{sup -3} S cm{sup -1} under saturated humidity condition at 150 deg. C. The materials can be expected to be used for the application of temperature tolerant polymer electrolyte fuel cell.

  9. Synthesis and proton conducting properties of zirconia bridged hydrocarbon/phosphotungstic acid hybrid materials

    Recently, the organic/inorganic hybrid materials with flexibility, thermal, and chemical stabilities are extensively studied for the application of temperature tolerant polymer electrolyte fuel cells. This paper reports the preparation and properties of sol-gel derived proton conducting organic/inorganic materials based on zirconia bridged hydrocarbon phosphotungstic acids. The materials are molecular hybrids where linear hydrocarbons such as trimethylene glycols (TMGs) or octamethylene glycols (OMGs) are covalently bonded to zirconia interface to form macromolecular organic/inorganic networks. The hybrid materials become proton conducting polymer electrolytes by the addition of 12-phosphotungstic acids. The hybrid materials showed high thermal stability, and high protonic conductivity of 4x10-3 S cm-1 under saturated humidity condition at 150 deg. C. The materials can be expected to be used for the application of temperature tolerant polymer electrolyte fuel cell

  10. Synthesis and proton conducting properties of zirconia bridged hydrocarbon/phosphotungstic acid hybrid materials

    Jedeok Kim; Honma, Itaru [National Institute of Advanced Science and Technology (AIST), Energy Electronics Inst., Tsukuba, Ibaraki (Japan)

    2004-08-15

    Recently, the organic/inorganic hybrid materials with flexibility, thermal, and chemical stabilities are extensively studied for the application of temperature tolerant polymer electrolyte fuel cells. This paper reports the preparation and properties of sol-gel derived proton conducting organic/inorganic materials based on zirconia bridged hydrocarbon phosphotungstic acids. The materials are molecular hybrids where linear hydrocarbons such as trimethylene glycols (TMGs) or octamethylene glycols (OMGs) are covalently bonded to zirconia interface to form macromolecular organic/inorganic networks. The hybrid materials become proton conducting polymer electrolytes by the addition of 12-phosphotungstic acids. The hybrid materials showed high thermal stability, and high protonic conductivity of 4 x 10{sup -3} S cm{sup -1} under saturated humidity condition at 150 deg C. The materials can be expected to be used for the application of temperature tolerant polymer electrolyte fuel cell. (Author)

  11. Diaquabis(pyridine-2-carboxylato-κ2N,O)cobalt(II)

    G. S. Huang

    2008-01-01

    In the molecule of the title compound, [Co(C6H4NO2)2(H2O)2], the coordination environment around the CoII atom is distorted octahedral; two N and two O atoms of the pyridine-2-carboxylate ligands lie in the equatorial plane and the two water O atoms in the axial positions. In the crystal structure, intermolecular O—H...O hydrogen bonds link the molecules, forming a supramoleular network structure.

  12. Tailoring the Synergistic Bronsted-Lewis acidic effects in Heteropolyacid catalysts: Applied in Esterification and Transesterification Reactions.

    Tao, Meilin; Xue, Lifang; Sun, Zhong; Wang, Shengtian; Wang, Xiaohong; Shi, Junyou

    2015-01-01

    In order to investigate the influences of Lewis metals on acidic properties and catalytic activities, a series of Keggin heteropolyacid (HPA) catalysts, HnPW11MO39 (M = Ti(IV), Cu(II), Al(III), Sn(IV), Fe(III), Cr(III), Zr(IV) and Zn(II); for Ti and Zr, the number of oxygen is 40), were prepared and applied in the esterification and transesterification reactions. Only those cations with moderate Lewis acidity had a higher impact. Ti Substituted HPA, H5PW11TiO40, posse lower acid content compared with Ti(x)H(3-4x)PW12O40 (Ti partial exchanged protons in saturated H3PW12O40), which demonstrated that the Lewis metal as an addenda atom (H5PW11TiO40) was less efficient than those as counter cations (Ti(x)H(3-4x)PW12O40). On the other hand, the highest conversion reached 92.2% in transesterification and 97.4% in esterification. Meanwhile, a good result was achieved by H5PW11TiO40 in which the total selectivity of DAG and TGA was 96.7%. In addition, calcination treatment to H5PW11TiO40 make it insoluble in water which resulted in a heterogeneous catalyst feasible for reuse. PMID:26374393

  13. Tailoring the Synergistic Bronsted-Lewis acidic effects in Heteropolyacid catalysts: Applied in Esterification and Transesterification Reactions

    Tao, Meilin; Xue, Lifang; Sun, Zhong; Wang, Shengtian; Wang, Xiaohong; Shi, Junyou

    2015-09-01

    In order to investigate the influences of Lewis metals on acidic properties and catalytic activities, a series of Keggin heteropolyacid (HPA) catalysts, HnPW11MO39 (M = TiIV, CuII, AlIII, SnIV, FeIII, CrIII, ZrIV and ZnII; for Ti and Zr, the number of oxygen is 40), were prepared and applied in the esterification and transesterification reactions. Only those cations with moderate Lewis acidity had a higher impact. Ti Substituted HPA, H5PW11TiO40, posse lower acid content compared with TixH3-4xPW12O40 (Ti partial exchanged protons in saturated H3PW12O40), which demonstrated that the Lewis metal as an addenda atom (H5PW11TiO40) was less efficient than those as counter cations (TixH3-4xPW12O40). On the other hand, the highest conversion reached 92.2% in transesterification and 97.4% in esterification. Meanwhile, a good result was achieved by H5PW11TiO40 in which the total selectivity of DAG and TGA was 96.7%. In addition, calcination treatment to H5PW11TiO40 make it insoluble in water which resulted in a heterogeneous catalyst feasible for reuse.

  14. Bile acid sequestrants

    Hansen, Morten; Sonne, David P; Knop, Filip K

    2014-01-01

    Bile acids are synthesized in the liver from cholesterol and have traditionally been recognized for their role in absorption of lipids and in cholesterol homeostasis. In recent years, however, bile acids have emerged as metabolic signaling molecules that are involved in the regulation of lipid and...... glucose metabolism, and possibly energy homeostasis, through activation of the bile acid receptors farnesoid X receptor (FXR) and TGR5. Bile acid sequestrants (BASs) constitute a class of drugs that bind bile acids in the intestine to form a nonabsorbable complex resulting in interruption of the...... enterohepatic circulation. This increases bile acid synthesis and consequently reduces serum low-density lipoprotein cholesterol. Also, BASs improve glycemic control in patients with type 2 diabetes. Despite a growing understanding of the impact of BASs on glucose metabolism, the mechanisms behind their glucose...

  15. Magnetic excitations in the spinel compound Li$_x$[Mn$_{1.96}$Li$_{0.04}$]O$_4$ (x= 0.2, 0.6, 0.8, 1.0): how a classical system can mimic quantum critical scaling

    Heitmann, T.; Schmets, A. J. M.; Gaddy, J; Lamsal, J.; Petrovic, M.; Vojta, T.; Montfrooij, W.

    2009-01-01

    We present neutron scattering results on the magnetic excitations in the spinel compounds Li$_x$[Mn$_{1.96}$Li$_{0.04}$]O$_4$ (x= 0.2, 0.6, 0.8, 1.0). We show that the dominant excitations below T ~ 70 K are determined by clusters of Mn^4+ ions, and that these excitations mimic the E/T-scaling found in quantum critical systems that also harbor magnetic clusters, such as CeRu$_{0.5}$Fe$_{1.5}$Ge$_2$. We argue that our results for this classical spinel compound show that the unusual response at...

  16. Docosahexaenoic Acid Neurolipidomics

    Niemoller, Tiffany D.; Bazan, Nicolas G.

    2009-01-01

    Mediator lipidomics is a field of study concerned with the characterization, structural elucidation and bioactivity of lipid derivatives generated by enzymatic activity. Omega-3 fatty acids have beneficial effects for vision, brain function, cardiovascular function, and immune-inflammatory responses. Docosahexaenoic acid [DHA; 22:6(n-3)], the most abundant essential omega-3 fatty acid in the human body, is selectively enriched and avidly retained in the central nervous system as an acyl chain...

  17. Fatty acids and epigenetics

    Burdge, Graham C; Lillycrop, Karen A.

    2014-01-01

    Purpose of review The purpose of this review is to assess the findings of recent studies on the effects of fatty acids on epigenetic process and the role of epigenetics in regulating fatty acid metabolism. Recent findings The DNA methylation status of the Fads2 promoter was increased in the liver of the offspring of mice fed an ?-linolenic acid-enriched diet during pregnancy. In rats, increasing total maternal fat intake during pregnancy and lactation induced persistent hypermethyl...

  18. USGS Tracks Acid Rain

    Gordon, John D.; Nilles, Mark A.; Schroder, LeRoy J.

    1995-01-01

    The U.S. Geological Survey (USGS) has been actively studying acid rain for the past 15 years. When scientists learned that acid rain could harm fish, fear of damage to our natural environment from acid rain concerned the American public. Research by USGS scientists and other groups began to show that the processes resulting in acid rain are very complex. Scientists were puzzled by the fact that in some cases it was difficult to demonstrate that the pollution from automobiles and factories was causing streams or lakes to become more acidic. Further experiments showed how the natural ability of many soils to neutralize acids would reduce the effects of acid rain in some locations--at least as long as the neutralizing ability lasted (Young, 1991). The USGS has played a key role in establishing and maintaining the only nationwide network of acid rain monitoring stations. This program is called the National Atmospheric Deposition Program/National Trends Network (NADP/NTN). Each week, at approximately 220 NADP/NTN sites across the country, rain and snow samples are collected for analysis. NADP/NTN site in Montana. The USGS supports about 72 of these sites. The information gained from monitoring the chemistry of our nation's rain and snow is important for testing the results of pollution control laws on acid rain.

  19. Azetidinic amino acids

    Bräuner-Osborne, Hans; Bunch, Lennart; Chopin, Nathalie;

    2005-01-01

    A set of ten azetidinic amino acids, that can be envisioned as C-4 alkyl substituted analogues of trans-2-carboxyazetidine-3-acetic acid (t-CAA) and/or conformationally constrained analogues of (R)- or (S)-glutamic acid (Glu) have been synthesized in a diastereo- and enantiomerically pure form from...... two diastereoisomers that were easily separated and converted in two steps into azetidinic amino acids. Azetidines 35-44 were characterized in binding studies on native ionotropic Glu receptors and in functional assays at cloned metabotropic receptors mGluR1, 2 and 4, representing group I, II and III...

  20. Halogenated fatty acids

    Mu, Huiling; Wesén, Clas; Sundin, Peter

    1997-01-01

    Chlorinated fatty acids have been found to be major contributors to organohalogen compounds in fish, bivalves, jellyfish, and lobster, and they have been indicated to contribute considerably to organohalogens in marine mammals. Brominated fatty acids have been found in marine sponges. Also....... However, a natural production of halogenated fatty acids is also possible. In this paper we summarize the present knowledge of the occurrence of halogenated fatty acids in lipids and suggested ways of their formation. In Part II (Trends Anal. Chem. 16 (1997) 274) we deal with methods of their...

  1. The acid rain primer

    Acid rain continues to be a major problem in North America, and particularly in eastern Canada. This report introduced the topic of acid rain and discussed its formation, measurement, sources, and geographic distribution. The major sources of sulphur dioxide in Canada are smelting metals, burning coal for electrical power generation, industrial emissions (e.g., pulp and paper, petroleum and aluminum industry), and oil and gas extraction and refining. In Canada, the largest source of nitrogen oxide is the burning of fossil fuels by the transportation sector. Problem areas for acid rain in Canada were identified. The effects of acid rain were examined on lakes and aquatic ecosystems, forests and soils, human-made structures and materials, human health, and on visibility. Acid rain policies and programs were then presented from a historical and current context. Ecosystem recovery from acid rain was discussed with reference to acid rain monitoring, atmospheric response to reductions in acid-causing emissions, and ecosystem recovery of lakes, forests, and aquatic ecosystems. Challenges affecting ecosystem recovery were also presented. These challenges include drought and dry weather, decrease of base cations in precipitation, release of sulphate previously stored in soil, mineralization and immobilization of sulphur/sulphates. Last, the report discussed what still needs to be done to improve the problem of acid rain as well as future concerns. These concerns include loss of base cations from forested watersheds and nitrogen deposition and saturation. 21 refs., 2 tabs., 17 figs

  2. THIN-LAYER SEPARATION OF CITRIC ACID CYCLE INTERMEDIATES, LACTIC ACID, AND THE AMINO ACID TAURINE

    This paper describes a two-dimensional mixed-layer method for separating citric acid cycle intermediates, lactic acid and the amino acid taurine. The method cleanly separates all citric acid cycle intermediates tested, excepting citric acid and isocitric acid. The solvents are in...

  3. Sulfuric Acid Monohydrate: Formation and Heterogeneous Chemistry in the Stratosphere

    Zhang, Renyi; Leu, Ming-Taun; Keyser, Leon F.

    1995-01-01

    We have investigated some thermodynamic properties (i.e., freezing/melting points) and heterogeneous chemistry of sulfuric acid monohydrate (SAM, H2SO4.H2O), using a fast flow reactor coupled to a quadrupole mass spectrometer. The freezing point observations of thin liquid sulfuric acid films show that for acid contents between 75 and 85 wt % the monohydrate crystallizes readily at temperatures between 220 and 240 K on a glass substrate. Once formed, SAM can be thermodynamically stable in the H2O partial pressure range of (1-4) x 10(exp -4) torr and in the temperature range of 220-240 K. For a constant H2O partial pressure, lowering the temperature causes SAM to melt when the temperature and water partial pressure conditions are out of its stability regime. The reaction probability measurements indicate that the hydrolysis of N2O5 is significantly suppressed owing to the formation of crystalline SAM: The reaction probability on water-rich SAM (with higher relative humidity, or RH) is of the order of 10(exp -3) at 210 K and decreases by more than an order of magnitude for the acid-rich form (with lower RH). The hydrolysis rate of ClONO2 on water-rich SAM is even smaller, of the order of 10(exp -4) at 195 K. These reported values on crystalline SAM are much smaller than those on liquid solutions. No enhancement of these reactions is observed in the presence of HCl vapor at the stratospheric concentrations. In addition, Brunauer, Emmett, and Teller analysis of gas adsorption isotherms and photomicrography have been performed to characterize the surface roughness and porosities of the SAM substrate. The results suggest the possible formation of SAM in some regions of the middle- or low-latitude stratosphere and, consequently, much slower heterogeneous reactions on the frozen aerosols.

  4. Molecular Interaction of Pinic Acid with Sulfuric Acid

    Elm, Jonas; Kurten, Theo; Bilde, Merete;

    2014-01-01

    We investigate the molecular interactions between the semivolatile α-pinene oxidation product pinic acid and sulfuric acid using computational methods. The stepwise Gibbs free energies of formation have been calculated utilizing the M06-2X functional, and the stability of the clusters is evaluated...... from the corresponding ΔG values. The first two additions of sulfuric acid to pinic acid are found to be favorable with ΔG values of -9.06 and -10.41 kcal/mol. Addition of a third sulfuric acid molecule is less favorable and leads to a structural rearrangement forming a bridged sulfuric acid-pinic acid...... without the further possibility for attachment of either sulfuric acid or pinic acid. This suggests that pinic acid cannot be a key species in the first steps in nucleation, but the favorable interactions between sulfuric acid and pinic acid imply that pinic acid can contribute to the subsequent growth of...

  5. Amino Acid Crossword Puzzle

    Sims, Paul A.

    2011-01-01

    Learning the 20 standard amino acids is an essential component of an introductory course in biochemistry. Later in the course, the students study metabolism and learn about various catabolic and anabolic pathways involving amino acids. Learning new material or concepts often is easier if one can connect the new material to what one already knows;…

  6. Science of acid rain

    In this report, the mechanism of forming acid rain in the atmosphere and the process of its fall to ground, the mechanism of withering forests by acid substances, and the process of acidifying lakes and marshes are explained. Moreover, the monitoring networks for acid rain and the countermeasures are described. Acid rain is the pollution phenomena related to all environment, that is, atmosphere, hydrosphere, soilsphere, biosphere and so on, and it is a local environmental pollution problem, and at the same time, an international, global environmental pollution problem. In Japan, acid rain has fallen, but the acidification of lakes and marshes is not clear, and the damage to forests is on small scale. However in East Asia region, the release of sulfur oxides and nitrogen oxides is much, and the increase of the effects of acid rain is expected. It is necessary to devise the measures for preventing the damage due to acid rain. The global monitoring networks of World Meteorological Organization and United Nations Environment Program, and those in Europe, USA and Japan are described. The monitoring of acid rain in Japan is behind that in Europe and USA. (K.I.)

  7. Peptide Nucleic Acid Synthons

    2004-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  8. Peptide Nucleic Acids

    2004-01-01

    A novel class of compounds known as peptide nucleic acids, bind complementary DNA and RNA strands, and generally do so more strongly than the corresponding DNA or RNA strands while exhibiting increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from a...

  9. Locked nucleic acid

    Jepsen, Jan Stenvang; Sørensen, Mads D; Wengel, Jesper;

    2004-01-01

    Locked nucleic acid (LNA) is a class of nucleic acid analogs possessing very high affinity and excellent specificity toward complementary DNA and RNA, and LNA oligonucleotides have been applied as antisense molecules both in vitro and in vivo. In this review, we briefly describe the basic...

  10. Peptide Nucleic Acids

    2003-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  11. Peptide Nucleic Acids

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  12. Peptide Nucleic Acids (PNA)

    2002-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary ssDNA and RNA strands more strongly than a corresponding DNA. The peptide nucleic acids generally comprise ligands such as naturally occurring DNA bases attached to a peptide backbone through a suitable linker....

  13. Fatty Acid Biosynthesis IX

    Carey, E. M.; Hansen, Heinz Johs. Max; Dils, R.

    1972-01-01

    # 1. I. [I-14C]Acetate was covalently bound to rabbit mammary gland fatty acid synthetase by enzymic transacylation from [I-14C]acetyl-CoA. Per mole of enzyme 2 moles of acetate were bound to thiol groups and up to I mole of acetate was bound to non-thiol groups. # 2. 2. The acetyl-fatty acid...

  14. Characterization of acid tars

    Acid tars from the processing of petroleum and petrochemicals using sulfuric acid were characterized by gas chromatography/mass spectrometry (GC/MS), inductively coupled plasma/optical emission spectrometry (ICP/OES), differential scanning calorimetry (DSC), Fourier transform infrared (FTIR) spectrometry, and scanning electron microscopy/energy dispersive X-ray (SEM/EDX) micro-analysis. Leaching of contaminants from the acid tars in 48 h batch tests with distilled water at a liquid-to-solid ratio 10:1 was also studied. GC/MS results show that the samples contained aliphatic hydrocarbons, cyclic hydrocarbons, up to 12 of the 16 USEPA priority polycyclic aromatic hydrocarbons (PAHs), and numerous other organic groups, including organic acids (sulfonic acids, carboxylic acids and aromatic acids), phenyl, nitrile, amide, furans, thiophenes, pyrroles, and phthalates, many of which are toxic. Metals analysis shows that Pb was present in significant concentration. DSC results show different transition peaks in the studied samples, demonstrating their complexity and variability. FTIR analysis further confirmed the presence of the organic groups detected by GC/MS. The SEM/EDX micro-analysis results provided insight on the surface characteristics of the samples and show that contaminants distribution was heterogeneous. The results provide useful data on the composition, complexity, and variability of acid tars; information which hitherto have been scarce in public domain.

  15. Halogenated fatty acids

    Mu, Huiling; Wesén, Clas; Sundin, Peter

    1997-01-01

    . However, a natural production of halogenated fatty acids is also possible. In this paper we summarize the present knowledge of the occurrence of halogenated fatty acids in lipids and suggested ways of their formation. In Part II (Trends Anal. Chem. 16 (1997) 274) we deal with methods of their...

  16. Structural Characterization of the Intermetallic Phase EuZn{sub x}In{sub 4-x} (x ≅ 1.1-1.2). Zn and In Site-Preferences in the BaAl{sub 4} Structure-Type from Computational Analysis

    You, Taesoo; Darone, Gregory M.; Bobev, Svilen [Univ. of Delaware, Newark (United States); Nam, Gnu; Kim, Youngjo [Chungbuk National Univ., Cheongju (Korea, Republic of)

    2013-06-15

    The ternary phase EuZn{sub x}In{sub 4-x} has been identified as the main product of reactions of Eu, Zn, and In by using the In-flux method and characterized by both powder and single-crystal X-ray diffraction. The structure belongs to the common BaAl{sub 4}-type (tetragonal space group I4/mmm, Pearson code tI10) with lattice parameters of a = 4.5610(9) A, c = 12.049(3) A for composition EuZn{sub 1.10(12)}In{sub 2.90} and a = 4.5463(3) A, c = 12.028(2) A for composition EuZn{sub 1.18(2)}In{sub 2.82}, respectively. In this structure, the Eu atoms are situated at the center of 18-vertex Fedorov polyhedra made of Zn and In atoms, where the 4d site is preferentially occupied by In and the 4e site is occupied by randomly mixed Zn and In atoms. Theoretical investigations using tight-binding linear muffin-tin orbital (TB-LMTO) method provide rationale for the observed site preferences and suggest potentially wider homogeneity range than the experimentally established for EuZnxIn{sub 4-x} (x ≅ 1.1)

  17. Canadian acid rain policy

    On March 13 of 1991, the Prime Minister of Canada, Brian Mulroney and the President of the United States of America, George Bush, signed an Agreement on Air Quality. This agreement enshrines Principle 21 of the 1972 Stockholm Declaration which states that countries are to ensure that activities within their jurisdiction do not cause damage to the environment of another country. This agreement also includes provisions for controlling acid rain. The Agreement on Air Quality followed years of discussion between the two countries and is a significant milestone in the history of Canadian acid rain policy. This paper begins by describing Canadian acid rain policy and its evolution. The paper also outlines the Canada-United States Air Quality Agreement and the effect of the acid rain provisions on deposition in Canada. Finally, it considers the future work that must be undertaken to further resolve the acid rain problem. 8 refs., 5 figs., 1 tab

  18. Synthesis of aminoaldonic acids

    Jørgensen, Christel Thea

    With the aim of synthesising aminoaldonic acids, two 2-acetamido-2-deoxyaldonolactones with D-galacto (6) and D-arabino (11) configuration were prepared from acetylated sugar formazans in analogy with a known procedure. Empolying the same procedure to acetylated sugar phenylhydrazones gave mixtures...... of 2,5-anhydrides and not the expected 2-acetamido-2-deoxy aldose phenylhydrazones. The acetylated phenylhydrazones were found to eliminate acetic acid when heated in aqueous ethanol and 1-phenylazoalkenes could be isolated by crystallisation. By this method the 17, 20, 23 and 25 were prepared from...... aziridino amides 43 and 51 were reductively cleaved with hydrazine to give 3-amino-2,3-dideoxyhexonhydrazides 83 and 85, which were easily converted into the corresponding lactone 84 and acid 86. The aziridine ring of 43 and 51 was also opened with acetic acid to give the 3-amino-3-deoxyhexonic acids 79 and...

  19. Fusidic acid in dermatology

    Schöfer, Helmut; Simonsen, Lene

    1995-01-01

    Studies on the clinical efficacy of fusidic acid in skin and soft-tissue infections (SSTIs), notably those due to Staphylococcus aureus, are reviewed. Oral fusidic acid (tablets dosed at 250 mg twice daily, or a suspension for paediatric use at 20 mg/kg/day given as two daily doses) has shown good...... efficacy and tolerability. Similarly, plain fusidic acid cream or ointment used two or three times daily in SSTIs such as impetigo are clinically and bacteriologically effective, with minimal adverse events. Combination formulations of fusidic acid with 1% hydrocortisone or 0.1% betamethasone achieve...... excellent results in infected eczema by addressing both inflammation and infection. A new lipid-rich combination formulation provides an extra moisturizing effect. Development of resistance to fusidic acid has remained generally low or short-lived and can be minimized by restricting therapy to no more than...

  20. Hydrolysis of Pentosan for Furfural Preparing Using Sulfuric Acid Catalyst to Improve Diesel Engine Fuel Quality

    The investigation on furfural preparation from peanut shell using sulfuric acid catalyst has been done. Furfural is an organic solvent used in industry especially petroleum industry. The purpose of this investigation is to know the effects of sulfuric acid concentration and solvent feed ratio towards furfural resulted and the reaction kinetics. The experiment was performed in the batch reactor. The result of this investigation showed that the process optimum condition was reached at sulfuric acid concentration of 7% and the solvent feed ratio of 12.5. The result at the optimum condition above was 5.97% of furfural. The relation between percentage of furfural resulted (Y) and sulfuric acid concentration (X) is Y = 0.893 X1.7023 . e-0.2554X with average deviation of 5.880 %. The relation between percentage of furfural resulted (Y) and solvent feed ratio (X) is Y = -53.0411 + 9.4137 X - 0.3780 X2 with average deviation 5.154 %. The relation between reaction rate constant (Y) and sulfuric acid concentration (X) is Y = 3.1916 . 10-3 + 8.2432 . 10-3 X - 5.2324 . 10-4 X2 with average deviation 8.024 %. (author)

  1. Sulfuric Acid on Europa

    1999-01-01

    Frozen sulfuric acid on Jupiter's moon Europa is depicted in this image produced from data gathered by NASA's Galileo spacecraft. The brightest areas, where the yellow is most intense, represent regions of high frozen sulfuric acid concentration. Sulfuric acid is found in battery acid and in Earth's acid rain. This image is based on data gathered by Galileo's near infrared mapping spectrometer.Europa's leading hemisphere is toward the bottom right, and there are enhanced concentrations of sulfuric acid in the trailing side of Europa (the upper left side of the image). This is the face of Europa that is struck by sulfur ions coming from Jupiter's innermost moon, Io. The long, narrow features that crisscross Europa also show sulfuric acid that may be from sulfurous material extruded in cracks. Galileo, launched in 1989, has been orbiting Jupiter and its moons since December 1995. JPL manages the Galileo mission for NASA's Office of Space Science, Washington DC. JPL is a division of the California Institute of Technology, Pasadena, CA.

  2. Influences of hydrogen-induced amorphization and annealing treatment on gaseous hydrogen storage properties of La{sub 1−x}Pr{sub x}MgNi{sub 3.6}Co{sub 0.4} (x = 0–0.4) alloys

    Zhai, Tingting [Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China); College of Science, Northeastern University, Shenyang 110819 (China); Yang, Tai; Yuan, Zeming; Xu, Sheng; Bu, Wengang [Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China); Qi, Yang [College of Science, Northeastern University, Shenyang 110819 (China); Zhang, Yanghuan, E-mail: zhangyh59@sina.com [Department of Functional Material Research, Central Iron and Steel Research Institute, Beijing 100081 (China); Key Laboratory of Integrated Exploitation of Baiyun Obo Multi-Metal Resources, Inner Mongolia University of Science and Technology, Baotou 014010 (China)

    2015-08-05

    Highlights: • The La–Mg–Ni-based AB{sub 2}-type alloys were prepared by casting. • La was substituted by a small amount of Pr in the experimental alloys. • The hydrogen absorption/desorption cycling properties of the alloys were studied. • The influences of hydrogen-induced amorphization were investigated in details. • The annealing treatment was applied to recover hydrogen storage capacity. - Abstract: La{sub 1−x}Pr{sub x}MgNi{sub 3.6}Co{sub 0.4} (x = 0–0.4) alloys are prepared by vacuum induction melting. The phase composition and microstructure of the as-cast alloys is characterized by X-ray diffraction (XRD) and scanning electron microscope (SEM). The gaseous hydrogen absorption capacity of the alloys was measured by an automatically controlled Sieverts apparatus. The results indicate that the as-cast alloys consist of two phases of LaMgNi{sub 4} and LaNi{sub 5}. The maximum gaseous hydrogen storage capacity of the La{sub 1−x}Pr{sub x}MgNi{sub 3.6}Co{sub 0.4} (x = 0–0.4) alloys is 1.768, 1.745, 1.721, 1.681 and 1.653 wt%, respectively, under 3 MPa H{sub 2} at 373 K. But the hydrogen storage capacity after 20 cycles decays off to 0.746, 0.843, 0.947, 1.003 and 1.10 wt%, respectively. In order to reveal the mechanism of rapid degradation of the capacity, the structures of the alloys before and after hydrogen absorption/desorption cycle were analyzed. SEM observation displays that the micro-cracks can be clearly seen on the surface of the alloy particles after 20 cycles. XRD detection finds that the repeated hydrogen absorption/desorption cycles give rise to a obvious broadening of the diffraction peaks of the alloys, exhibiting a typical amorphous structure, which is termed as hydrogen-induced amorphization. The La{sub 1−x}Pr{sub x}MgNi{sub 3.6}Co{sub 0.4} (x = 0–0.4) alloys after 20 cycles were annealed at 623 K for 8 h, finding that the hydrogen storage capacity of the alloys recovers to 1.348, 1.365, 1.50, 1.485 and 1.30 wt

  3. Difficult Decisions: Acid Rain.

    Miller, John A.; Slesnick, Irwin L.

    1989-01-01

    Discusses some of the contributing factors and chemical reactions involved in the production of acid rain, its effects, and political issues pertaining to who should pay for the clean up. Supplies questions for consideration and discussion. (RT)

  4. Folic acid in diet

    ... green leafy vegetables Dried beans and peas (legumes) Citrus fruits and juices Fortified means that vitamins have ... A.D.A.M. Editorial team. Related MedlinePlus Health Topics Folic Acid Browse the Encyclopedia A.D. ...

  5. Citric acid urine test

    ... usually done while you are on a normal diet. Ask your provider for more information. ... acidosis and a tendency to form calcium kidney stones. The ... acid levels: A high carbohydrate diet Estrogen therapy Vitamin D

  6. Stomach acid test

    Gastric acid secretion test ... The test is done after you have not eaten for a while so fluid is all that remains in ... injected into your body. This is done to test the ability of the cells in the stomach ...

  7. Azelaic Acid Topical

    ... pores and by decreasing production of keratin, a natural substance that can lead to the development of ... acid controls acne and rosacea but does not cure these conditions. It may take 4 weeks or ...

  8. Acid rain: An overview

    US Fish and Wildlife Service, Department of the Interior — Summary of the effects of acid rain and related processes, sources, issues, corrective actions, research, current law, potential solutions, political solutions,...

  9. Ethylenediaminetetraacetic acid in endodontics

    Mohammadi, Zahed; Shalavi, Sousan; Jafarzadeh, Hamid

    2013-01-01

    Ethylenediaminetetraacetic acid (EDTA) is a chelating agent can bind to metals via four carboxylate and two amine groups. It is a polyamino carboxylic acid and a colorless, water-soluble solid, which is widely used to dissolve lime scale. It is produced as several salts, notably disodium EDTA and calcium disodium EDTA. EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. A review of the literature and a discussion of the different indications and considerations for...

  10. Utilization of acid tars

    Frolov, A.F.; Denisova, T.L.; Aminov, A.N.

    1987-01-01

    Freshly produced acid tar (FPAT), obtained as refinery waste in treating petroleum oils with sulfuric acid and oleum, contains 80% or more sulfuric acid. Of such tars, pond acid tars, which contain up to 80% neutral petroleum products and sulfonated resins, are more stable, and have found applications in the production of binders for paving materials. In this article the authors are presenting results obtained in a study of the composition and reactivity of FPAT and its stability in storage in blends with asphalts obtained in deasphalting operations, and the possibility of using the FPAT in road construction has been examined. In this work, wastes were used which were obtained in treating the oils T-750, KhF-12, I-8A, and MS-14. Data on the change in group chemical composition of FPAT are shown, and the acidity, viscosity, needle penetration, and softening point of acid tars obtained from different grades of oils are plotted as functions of the storage time. It is also shown that the fresh and hardened FPATs differ in their solubilities in various solvents.

  11. Fatty Acid Biosynthesis IX

    Carey, E. M.; Hansen, Heinz Johs. Max; Dils, R.

    1972-01-01

    # 1. I. [I-14C]Acetate was covalently bound to rabbit mammary gland fatty acid synthetase by enzymic transacylation from [I-14C]acetyl-CoA. Per mole of enzyme 2 moles of acetate were bound to thiol groups and up to I mole of acetate was bound to non-thiol groups. # 2. 2. The acetyl-fatty acid...... synthetase complex was isolated free from acetyl-CoA. It was rapidly hydrolysed at 30°C, but hydrolysis was greatly diminished at o°C and triacetic lactone synthesis occurred. In the presence of malonyl-CoA and NADPH, all the acetate bound to fatty acid synthetase was incorporated into long-chain fatty acids....... Hydrolysis of bound acetate and incorporation of bound acetate into fatty acids were inhibited to the same extent by guanidine hydrochloride. # 3. 3. Acetate was also covalently bound to fatty acid synthetase by chemical acetylation with [I-14C]acetic anhydride in the absence of CoASH. A total of 60 moles of...

  12. Neutron Nucleic Acid Crystallography.

    Chatake, Toshiyuki

    2016-01-01

    The hydration shells surrounding nucleic acids and hydrogen-bonding networks involving water molecules and nucleic acids are essential interactions for the structural stability and function of nucleic acids. Water molecules in the hydration shells influence various conformations of DNA and RNA by specific hydrogen-bonding networks, which often contribute to the chemical reactivity and molecular recognition of nucleic acids. However, X-ray crystallography could not provide a complete description of structural information with respect to hydrogen bonds. Indeed, X-ray crystallography is a powerful tool for determining the locations of water molecules, i.e., the location of the oxygen atom of H2O; however, it is very difficult to determine the orientation of the water molecules, i.e., the orientation of the two hydrogen atoms of H2O, because X-ray scattering from the hydrogen atom is very small.Neutron crystallography is a specialized tool for determining the positions of hydrogen atoms. Neutrons are not diffracted by electrons, but are diffracted by atomic nuclei; accordingly, neutron scattering lengths of hydrogen and its isotopes are comparable to those of non-hydrogen atoms. Therefore, neutron crystallography can determine both of the locations and orientations of water molecules. This chapter describes the current status of neutron nucleic acid crystallographic research as well as the basic principles of neutron diffraction experiments performed on nucleic acid crystals: materials, crystallization, diffraction experiments, and structure determination. PMID:26227050

  13. Method for isolating nucleic acids

    Hurt, Jr., Richard Ashley; Elias, Dwayne A.

    2015-09-29

    The current disclosure provides methods and kits for isolating nucleic acid from an environmental sample. The current methods and compositions further provide methods for isolating nucleic acids by reducing adsorption of nucleic acids by charged ions and particles within an environmental sample. The methods of the current disclosure provide methods for isolating nucleic acids by releasing adsorbed nucleic acids from charged particles during the nucleic acid isolation process. The current disclosure facilitates the isolation of nucleic acids of sufficient quality and quantity to enable one of ordinary skill in the art to utilize or analyze the isolated nucleic acids for a wide variety of applications including, sequencing or species population analysis.

  14. Acidification and Acid Rain

    Norton, S. A.; Veselã½, J.

    2003-12-01

    Air pollution by acids has been known as a problem for centuries (Ducros, 1845; Smith, 1872; Camuffo, 1992; Brimblecombe, 1992). Only in the mid-1900s did it become clear that it was a problem for more than just industrially developed areas, and that precipitation quality can affect aquatic resources ( Gorham, 1955). The last three decades of the twentieth century saw tremendous progress in the documentation of the chemistry of the atmosphere, precipitation, and the systems impacted by acid atmospheric deposition. Chronic acidification of ecosystems results in chemical changes to soil and to surface waters and groundwater as a result of reduction of base cation supply or an increase in acid (H+) supply, or both. The most fundamental changes during chronic acidification are an increase in exchangeable H+ or Al3+ (aluminum) in soils, an increase in H+ activity (˜concentration) in water in contact with soil, and a decrease in alkalinity in waters draining watersheds. Water draining from the soil is acidified and has a lower pH (=-log [H+]). As systems acidify, their biotic community changes.Acidic surface waters occur in many parts of the world as a consequence of natural processes and also due to atmospheric deposition of strong acid (e.g., Canada, Jeffries et al. (1986); the United Kingdom, Evans and Monteith (2001); Sweden, Swedish Environmental Protection Board (1986); Finland, Forsius et al. (1990); Norway, Henriksen et al. (1988a); and the United States (USA), Brakke et al. (1988)). Concern over acidification in the temperate regions of the northern hemisphere has been driven by the potential for accelerating natural acidification by pollution of the atmosphere with acidic or acidifying compounds. Atmospheric pollution ( Figure 1) has resulted in an increased flux of acid to and through ecosystems. Depending on the ability of an ecosystem to neutralize the increased flux of acidity, acidification may increase only imperceptibly or be accelerated at a rate that

  15. Crystal and molecular structure of solvate eta2-tetrahydroborate o of pl,1'-bis(diphenylphosphino)ferrocene copper(1) with benzene [Fe(C5H4PPh2)]2CuBH4x2C6H6

    The complexes (Dppf)CuDH4 has been prepared by means of interaction between tetrahydroborate bis-(triethylphosphite) copper 1 and bis-(diphenyl-phosphino) ferrocene Dppf. Its solvate with benzene [Fe(C5H4PPh2)2]CuDH4x2C6H6 has been studied by the method of x-ray diffraction. Tetrahydroborate group is coordinated by Cu atom via two H atoms (Cu-H 1.65(6) and 1.60(6)A, the angle of HCuH being 66(3). The B-H distances involving hydrogen bridge atoms (1.17(7) and 1.23(6)A) are somewhat longer than B-H terminal bonds (1.05(8) and 1.04(6)A. Refs. 10, figs. 2, tabs. 2

  16. 采取4x-2x杂交从二倍体中把Bacillus thuringiensis cry 3Aa转基因导入四倍体马铃薯:倍数增加对转基因表达的影响和TPS杂种生产的意义

    A.A.T.Johnson; 谢国禄

    2004-01-01

    试验有3个目的:一是表明在第一次分裂恢复就产生非还原配子的二倍体马铃薯基因型中具有重经济意义的转基因;二是采用4x-2x杂交把转基因导入四倍体后代;三是分析倍数增加对四倍体后代中转基因表达的影响。通过非还原配子检测了倍数增加对马

  17. Synthesis and characterization of LiNi0.6CoxMn0.4-xO2 (x = 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3) with high-electrochemical performance for lithium-ion batteries

    A series of Ni0.6CoxMn0.4-x(OH)2 hydroxide precursors with x = 0.05, 0.1, 0.15, 0.2, 0.25 and 0.3 are prepared by co–precipitation method from sulfate solutions using NaOH and NH4OH as precipitation and complexing agents. Then, well–ordered layered LiNi0.6CoxMn0.4-xO2 are synthesized by sintering the mixture of as–prepared precursors and LiOH · H2O at 820 °C for 12 h in flowing oxygen. Their structural and electrochemical properties are investigated using X–ray diffraction(XRD), scanning electron microscope(SEM), X–ray photoelectron spectroscopy(XPS), charge–discharge test, Cyclic voltammetry(C–V) and electrochemical impedance spectroscopy (EIS). The increase of the Co content in LiNi0.6CoxMn0.4−xO2 leads to the decrease of the tap–density of the powders, the increase of discharge capacity and the deterioration of cycling performance. It also leads to the enhancement of the ratio Ni3+/Ni2+ in LiNi0.6CoxMn0.4−xO2, confirmed by the XPS analysis. The results show that the sample with x = 0.2 has the highest tap–density, delivers an initial discharge capacity of 172.3 mAh g−1 at 1C rate between 2.8 and 4.3 V, more than 94.1% of that is retained after 100 cycles, and also with excellent rate capability and high-temperature performance

  18. Acid Rain, pH & Acidity: A Common Misinterpretation.

    Clark, David B.; Thompson, Ronald E.

    1989-01-01

    Illustrates the basis for misleading statements about the relationship between pH and acid content in acid rain. Explains why pH cannot be used as a measure of acidity for rain or any other solution. Suggests that teachers present acidity and pH as two separate and distinct concepts. (RT)

  19. Amino acids in the sedimentary humic and fulvic acids

    Sardessai, S.

    Humic and fulvic acids isolated from a few sediment samples from Arabian Sea and Bay of Bengal were analysed for total hydrolysable amino acids concentration and their composition. The amono acids content of fulvic acids was higher than in the humic...

  20. Synthesis and anticonvulsant activity of novel bicyclic acidic amino acids

    Conti, Paola; De Amici, Marco; Joppolo Di Ventimiglia, Samuele;

    2003-01-01

    Bicyclic acidic amino acids (+/-)-6 and (+/-)-7, which are conformationally constrained homologues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested toward ionotropic and metabotropic glutamate receptor subtypes; both of them...

  1. EFFECT OF ACIDITY ON ACID-SENSITIVE UV CURING SYSTEM

    Qi-dao Chen; Bing Wu; Xiao-yin Hong

    1999-01-01

    By using diphenyliodonium salts with different counterions as photo acid generators (PAGs), the effect of acidity on ring-opening polymerization of epoxy monomers and polycondensation of polyol with hexamethoxymethyl melamine (HMMM) was studied. The result shows that the rate of ring-opening polymerization is evidently dependent on the acidity of the acid and strong photo-generated acid is required.However, there is a leveling effect in the polycondensation system; if the photo-generated acid is stronger than protonated HMMM, the acidity does not obviously affect the polycondensation rate.

  2. A Three-level 4 x 3 Conventinal Matrix Converter

    Rong, Runjie; Loh, Poh Chiang; Wang, Peter;

    2007-01-01

    This paper proposes a topology of a three-level 4 × 3 conventional matrix converter with 12 bi-directional switches. PWM control and modulation index compensation have been investigated. Operation theory has been verified by the simulation results using Matlab. The simulation results show that the...... switching output performance of the proposed matrix converter is more efficient than that of existing matrix converters....

  3. Littlest Seesaw model from S4 x U(1)

    King, Stephen F

    2016-01-01

    We show how a minimal (littlest) seesaw model involving two right-handed neutrinos and a very constrained Dirac mass matrix, with one texture zero and two independent Dirac masses, may arise from $S_4\\times U(1)$ symmetry. The resulting CSD3 form of neutrino mass matrix only depends on two real mass parameters plus one undetermined phase. We show how the phase may be fixed to be one of the cube roots of unity by extending the $S_4\\times U(1)$ symmetry to include a product of $Z_3$ factors together with a CP symmetry, which is spontaneously broken leaving a single residual $Z_3$ in the charged lepton sector and a residual $Z_2$ in the neutrino sector, with suppressed higher order corrections. With the phase chosen from the cube roots of unity to be $-2\\pi/3$, the model predicts a normal neutrino mass hierarchy with $m_1=0$, reactor angle $\\theta_{13}=8.7^\\circ$, solar angle $\\theta_{12}=34^\\circ$, atmospheric angle $\\theta_{23}=44^\\circ$, and CP violating oscillation phase $\\delta_{\\rm CP}=-93^\\circ$, dependin...

  4. The Experimental V4X Stirling Engine - A Pioneering Development

    Lundholm, Gunnar

    2003-11-01

    A Swedish double-acting 35 kW V4 Stirling engine was developed in a pioneering effort with a number of simplified and novel design features. The overall design was made with the intention to fit a passenger car. The engine used standard automotive journal bearing technology, a new robust crosshead design, and sliding seals. A balancing shaft was used to remove first-order imbalances. Cooler, regenerator and heater geometry were first inherited from the Philips 4-65 swash-plate engine. Later a sequence of experimental heaters were designed and tested. Very little has until now been published on this engine, since its development was discontinued in favour of the double-crankshaft U4 engines 4-95 (P40), 4-275 (P75 Mk II and III) and 4-123 (MOD1). These designs were in turn later abandoned (with exception of the solar P40 engine) because of problems with for instance rattling gears. The V4 design concept was then revived in the automotive 60 kW MOD2 engine and the successful Kockums submarine 75 kW V4-275 engine. This paper describes the innovative design features, heater performance results and applications used for the development of fast power control.

  5. Kaonic helium-4 X-ray measurement in SIDDHARTA

    Bazzi, M. [INFN, Laboratori Nazionali di Frascati, Frascati (Roma) (Italy); Beer, G. [Dep. of Phys. and Astro., Univ. of Victoria, Victoria B.C. (Canada); Bombelli, L. [Politechno di Milano, Sez. di Elettronica, Milano (Italy); Bragadireanu, A.M. [INFN, Laboratori Nazionali di Frascati, Frascati (Roma) (Italy); IFIN-HH, Magurele, Bucharest (Romania); Cargnelli, M. [Stefan-Meyer-Institut fuer subatomare Physik, Vienna (Austria); Corradi, G.; Curceanu, C.; D' Uffizi, A. [INFN, Laboratori Nazionali di Frascati, Frascati (Roma) (Italy); Fiorini, C.; Frizzi, T. [Politechno di Milano, Sez. di Elettronica, Milano (Italy); Ghio, F.; Girolami, B. [INFN Sez. di Roma I and Inst. Superiore di Sanita, Roma (Italy); Guaraldo, C. [INFN, Laboratori Nazionali di Frascati, Frascati (Roma) (Italy); Hayano, R.S. [Univ. of Tokyo, Tokyo (Japan); Iliescu, M. [INFN, Laboratori Nazionali di Frascati, Frascati (Roma) (Italy); IFIN-HH, Magurele, Bucharest (Romania); Ishiwatari, T., E-mail: tomoichi.ishiwatari@oeaw.ac.a [Stefan-Meyer-Institut fuer subatomare Physik, Vienna (Austria); Iwasaki, M. [RIKEN, The Inst. of Phys. and Chem. Research, Saitama (Japan); Kienle, P. [Stefan-Meyer-Institut fuer subatomare Physik, Vienna (Austria); Tech. Univ. Muenchen, Physik Dep., Garching (Germany); Levi Sandri, P. [INFN, Laboratori Nazionali di Frascati, Frascati (Roma) (Italy); Longoni, A. [Politechno di Milano, Sez. di Elettronica, Milano (Italy)

    2009-11-09

    The kaonic helium-4 3d->2p X-ray transition was measured in a gaseous target, where Compton scattering in helium is negligible. The X-rays were detected with large-area Silicon Drift Detectors (SDDs) using the timing information of the K{sup +}K{sup -} pairs produced by phi decays at the DAPHINE e{sup +}e{sup -} collider. A new value of the strong interaction shift of the kaonic {sup 4}He 2p state was determined to be 0+-6 (stat)+-2 (syst) eV, which confirms the recently obtained result by the KEK-PS E570 group.

  6. Determination of Sialic Acids by Acidic Ninhydrin Reaction

    Yao,Kenzabroh

    1987-12-01

    Full Text Available A new acidic ninhydrin method for determining free sialic acids is described. The method is based on the reaction of sialic acids with Gaitonde's acid ninhydrin reagent 2 which yields a stable color with an absorption maximum at 470 nm. The standard curve is linear in the range of 5 to 500 nmol of N-acetylneuraminic acid per 0.9 ml of reaction mixture. The reaction was specific only for sialic acids among the various sugars and sugar derivatives examined. Some interference of this method by cysteine, cystine and tryptophan was noted, although their absorption maxima differed from that of sialic acids. The interference by these amino acids was eliminated with the use of a small column of cation-exchange resin. The acidic ninhydrin method provides a simple and rapid method for the determination of free sialic acids in biological materials.

  7. Chemistry and electrochemistry in trifluoroacetic acid. Comparison with acetic acid

    As the trifluoroacetic acid is, with the acetic acid, one of most often used carboxylic acids as solvent, notably in organic chemistry, this research thesis addresses some relatively simple complexing and redox reactions to highlight the peculiar feature of this acid, and to explain its very much different behaviour with respect to acetic acid. The author develops the notion of acidity level in solvents of low dielectric constant. The second part addresses a specific solvent: BF3(CH3COOH)2. The boron trifluoride strengthens the acidity of acetic acid and modifies its chemical and physical-chemical properties. In the third part, the author compares solvent properties of CF3COOH and CH3COOH. Noticed differences explain why the trifluoroacetic acid is a more interesting reaction environment than acetic acid for reactions such as electrophilic substitutions or protein solubilisation

  8. Intravenous supplementation of acetate, glucose or essential amino acids to an energy and protein deficient diet in lactating dairy goats

    Safayi, S.; Nielsen, M. O.

    2013-01-01

    In the present experiment we aimed to study, if milk synthesis is more sensitive toward deficiency in supply of amino acids in early (EL) versus late lactation (LL), and if energy yielding substrates in the form of acetate (but not glucose) can contribute to sustain milk (protein) synthesis, when...... amino acid supply is suboptimal. Goats were fed a basal diet deficient in energy (90% of requirements) and protein (80% of requirements), and were randomly allocated to 4 treatments in a balanced 4 x 4 Latin square design. The treatments consisted of 4-d continuous intravenous infusions of isoosmotic...... for differential protein energy recommendations for ruminants across the lactation period. (C) 2012 Elsevier B.V. All rights reserved....

  9. K Basin Sludge Conditioning Testing: Nitric Acid Dissolution Testing of K East Canister Sludge

    This report describes tests performed by Pacific Northwest National Laboratory (PNNL) for Numatec Hanford Corporation (NHC) as part of the overall activities for the development of the K Basin Sludge Treatment System. These tests were conducted to examine the dissolution behavior of a K East Basin canister sludge composite in nitric acid at the following concentrations: 2 M, 4 M, 6 M, 7.8 M and 10 M and temperatures of 25 C and boiling. Assuming that the sludge was 100% uranium metal, a 4X stoichiometric excess of nitric acid was used for all testing, except that conducted at 4 M. In the 4 M nitric acid dissolution test, 50% excess nitric acid was used resulting in a dissolver solution with a significantly higher solids loading. The boiling tests were conducted for 11 hr, the 25 C dissolution tests were conducted from 24 hr to 2 weeks. For the 25 C dissolution testing, the weight percent residual solids was determined, however, chemical and radiochemical analyses were not performed

  10. Spectrophotometric determination of beryllium with sulfochlorophenol S in organo-aqueous acetic-acid media

    The possibility has been shown of photometric determination of beryllium with sulphochlorophenol S using an acetic acid-propanol mixture (1:1), containing 0.5-1.5 vol% of water, as the reaction medium. Under such conditions, the reaction between beryllium and sulphochlorophenol S is sensitive and selective with respect to some easily hydrolized elements (Sn, Bi, Sb, Hg) as well as to Ga, In, Tl, Zn in the presence of HCl. The following excess amounts do not interfere with the determination of 0.45 μg Be: Hg-1.2x104, Sb-6.2x103, In-2.5x103, Tl-2.0x103, Zn-1.4x103, Ga-1.2x103. The reaction between beryllium and sulphochlorophenol S is selective with respect to a number of complexing agents. Beryllium can be determined in the presence of 150000-200000 times its weight amounts of tartaric, citric and boric acids, 5000-sulphosalycilic acid, 6000-oxalic acid, 6000-dimethyl glyoxime, 150-8-hydroxyquinoline

  11. Fatty Acid Desaturases, Polyunsaturated Fatty Acid Regulation, and Biotechnological Advances

    Je Min Lee; Hyungjae Lee; SeokBeom Kang; Woo Jung Park

    2016-01-01

    Polyunsaturated fatty acids (PUFAs) are considered to be critical nutrients to regulate human health and development, and numerous fatty acid desaturases play key roles in synthesizing PUFAs. Given the lack of delta-12 and -15 desaturases and the low levels of conversion to PUFAs, humans must consume some omega-3 and omega-6 fatty acids in their diet. Many studies on fatty acid desaturases as well as PUFAs have shown that fatty acid desaturase genes are closely related to different human phys...

  12. Domoic Acid Epileptic Disease

    John S. Ramsdell

    2014-03-01

    Full Text Available Domoic acid epileptic disease is characterized by spontaneous recurrent seizures weeks to months after domoic acid exposure. The potential for this disease was first recognized in a human case study of temporal lobe epilepsy after the 1987 amnesic shellfish-poisoning event in Quebec, and was characterized as a chronic epileptic syndrome in California sea lions through investigation of a series of domoic acid poisoning cases between 1998 and 2006. The sea lion study provided a breadth of insight into clinical presentations, unusual behaviors, brain pathology, and epidemiology. A rat model that replicates key observations of the chronic epileptic syndrome in sea lions has been applied to identify the progression of the epileptic disease state, its relationship to behavioral manifestations, and to define the neural systems involved in these behavioral disorders. Here, we present the concept of domoic acid epileptic disease as a delayed manifestation of domoic acid poisoning and review the state of knowledge for this disease state in affected humans and sea lions. We discuss causative mechanisms and neural underpinnings of disease maturation revealed by the rat model to present the concept for olfactory origin of an epileptic disease; triggered in dendodendritic synapases of the olfactory bulb and maturing in the olfactory cortex. We conclude with updated information on populations at risk, medical diagnosis, treatment, and prognosis.

  13. A Demonstration of Acid Rain

    Fong, Man Wai

    2004-01-01

    A demonstration showing acid rain formation is described. Oxides of sulfur and nitrogen that result from the burning of fossil fuels are the major pollutants of acid rain. In this demonstration, SO[subscript 2] gas is produced by the burning of matches. An acid-base indicator will show that the dissolved gas turns an aqueous solution acidic.

  14. Biological properties of lipoic acid

    Anna Bilska; Lidia Włodek

    2002-01-01

    Lipoic acid is a prostetic group of H-protein of the glycine cleavage system and the dihydrolipoamide acyltransferases (E2) of the pyruvate, alpha-ketoglutarate and branched-chain alpha-keto acid dehydrogenase complexes. Lipoic acid and its reduced form, dihydrolipoic acid, reacts with oxygen reactive species. This paper reviews the beneficial effects in oxidative stress models or clinical conditions.

  15. Gaseous ion-composition measurements in the young exhaust plume of jet aircraft at cruising altitudes. Implications for aerosols and gaseous sulfuric acid

    Arnold, F.; Wohlfrom, K.H.; Klemm, M.; Schneider, J.; Gollinger, K. [Max-Planck-Inst. for Nuclear Physics, Heidelberg (Germany); Schumann, U.; Busen, R. [Deutsche Forschungsanstalt fuer Luft- und Raumfahrt e.V. (DLR), Wessling (Germany). Inst. fuer Physik der Atmosphaere

    1997-12-31

    Mass spectrometric measurements were made in the young exhaust plume of an Airbus (A310) at cruising altitudes at distances between 400 and 800 m behind the Airbus (averaged plume age: 3.4 sec). The measurements indicate that gaseous sulfuric acid (GSA) number densities were less than 1.3 x 10{sup 8} cm{sup -3} which is smaller than the expected total sulfuric acid. Hence the missing sulfuric acid must have been in the aerosol phase. These measurements also indicate a total aerosol surface area density A{sub T} {<=} 5.4 x 10{sup -5} cm{sup 2} per cm{sup 3} which is consistent with simultaneously measured soot and water contrail particles. However, homogeneous nucleation leading to (H{sub 2}SO{sub 4}){sub x}(H{sub 2}O){sub y}-clusters can not be ruled out. (author) 16 refs.

  16. Amino acid analysis.

    Crabb, J W; West, K A; Dodson, W S; Hulmes, J D

    2001-05-01

    Amino acid analysis (AAA) is one of the best methods to quantify peptides and proteins. Two general approaches to quantitative AAA exist, namely, classical postcolumn derivatization following ion-exchange chromatography and precolumn derivatization followed by reversed-phase HPLC (RP-HPLC). Excellent instrumentation and several specific methodologies are available for both approaches, and both have advantages and disadvantages. This unit focuses on picomole-level AAA of peptides and proteins using the most popular precolumn-derivatization method, namely, phenylthiocarbamyl amino acid analysis (PTC-AAA). It is directed primarily toward those interested in establishing the technology with a modest budget. PTC derivatization and analysis conditions are described, and support and alternate protocols describe additional techniques necessary or useful for most any AAA method--e.g., sample preparation, hydrolysis, instrument calibration, data interpretation, and analysis of difficult or unusual residues such as cysteine, tryptophan, phosphoamino acids, and hydroxyproline. PMID:18429107

  17. Halogenated fatty acids

    Mu, Huiling; Sundin, Peter; Wesén, Clas

    1997-01-01

    Halogenated fatty acids are the major contributors to organohalogen compounds in lipids of marine mammals, fish, and bivalves. For the initial characterization of these recently noticed compounds, a determination of the halogen concentration has usually been combined with some lipid isolation and...... separation method. This review covers separation by solid phase chromatography, gel permeation chromatography, and liquid-liquid extraction, followed by halogen determination. All studies performed according to this outline have indicated that the major organohalogen compounds are chlorinated fatty acids...... bound in different lipids. For the detection and identification of individual, halogenated fatty acid methyl esters (FAMEs) liberated from the lipids, gas chromatography (GC) has been employed together with detection methods such as electron capture detection, electrolytic conductivity detection (ELCD...

  18. Time resolved fluorescence anisotropy of basic dyes bound to poly(methacrylic acid in solution

    Oliveira Hueder Paulo M. de

    2003-01-01

    Full Text Available Solutions of atactic poly(methacrylic acid, PMAA, with molecular weights in the range of (1.6 to 3.4 x 10(5 g mol-1, and labeled with the fluorescent dyes 9-aminoacridine or Nile blue were studied by photophysical measurements as a function of solvent viscosity and polarity. The conformational behavior of the PMAA chain segments around the fluorescent probe was reported by the change in the rotational diffusion of the dyes. Ethylene glycol swells the polymer chain compared with the more contracted conformation of PMAA in 50% water/ethylene glycol. The change in the rotational relaxation time of the dye bound to PMAA with the decrease of water content in the solvent mixture indicates a progressive expansion of polymer chain to a more open coil form in solution.

  19. [Nicotinic acid and nicotinamide].

    Kobayashi, M; Shimizu, S

    1999-10-01

    Nicotinic acid and nicotinamide are called niacin. They are the antipellagra vitamin essential to many animals for growth and health. In human being, niacin is believed necessary together with other vitamins for the prevention and cure of pellagra. Niacin is widely distributed in nature; appreciable amounts are found in liver, fish, yeast and cereal grains. Nicotinamide is a precursor of the coenzyme NAD and NADP. Some of the most understood metabolic processes that involve niacin are glycolysis, fatty acid synthesis and respiration. Niacin is also related to the following diseases: Hartnup disease; blue diaper syndrome; tryptophanuria; hydroxykynureninuria; xanthurenic aciduria; Huntington's disease. PMID:10540864

  20. Whither Acid Rain?

    Peter Brimblecombe

    2000-01-01

    Acid rain, the environmental cause célèbre of the 1980s seems to have vanished from popular conscience. By contrast, scientific research, despite funding difficulties, has continued to produce hundreds of research papers each year. Studies of acid rain taught much about precipitation chemistry, the behaviour of snow packs, long-range transport of pollutants and new issues in the biology of fish and forested ecosystems. There is now evidence of a shift away from research in precipitation and s...

  1. A very acid rocket

    Benoit Browaeys, D.

    1996-04-01

    The french rocket Ariane is the cause of environmental pollution. These effects are discussed in this article. Chloric acid and aluminium are in question: chloric acid is responsible of leaves necrosis and pulmonary diseases among the rats. For the man, the danger would be that drinking water could be contaminated by aluminium, which is neuro toxic with serious chronic effects. It is implicated in Alzheimer disease. But no studies has been made to search aluminium in drinking water of Sinnamary and Kourou. (N.C.). 8 refs., 2 figs.

  2. Ethylenediaminetetraacetic acid in endodontics.

    Mohammadi, Zahed; Shalavi, Sousan; Jafarzadeh, Hamid

    2013-09-01

    Ethylenediaminetetraacetic acid (EDTA) is a chelating agent can bind to metals via four carboxylate and two amine groups. It is a polyamino carboxylic acid and a colorless, water-soluble solid, which is widely used to dissolve lime scale. It is produced as several salts, notably disodium EDTA and calcium disodium EDTA. EDTA reacts with the calcium ions in dentine and forms soluble calcium chelates. A review of the literature and a discussion of the different indications and considerations for its usage are presented. PMID:24966721

  3. Whither Acid Rain?

    Peter Brimblecombe

    2000-01-01

    Full Text Available Acid rain, the environmental cause célèbre of the 1980s seems to have vanished from popular conscience. By contrast, scientific research, despite funding difficulties, has continued to produce hundreds of research papers each year. Studies of acid rain taught much about precipitation chemistry, the behaviour of snow packs, long-range transport of pollutants and new issues in the biology of fish and forested ecosystems. There is now evidence of a shift away from research in precipitation and sulfur chemistry, but an impressive theoretical base remains as a legacy.

  4. Boric acid concentration monitoring

    Boric acid concentration was measured by thermal neutron absorption in the study of the boric acid sorption and desorption curves on an anion exchange resin. Ra-Be 18.5 GBq and Am-Be 111 GBq sources and water as a moderator were used. The SNM 12 cylindrical corona detector with 10B placed in the middle of the measuring cell was used for neutron flux measurement. The HP 9600 E computer system was used for measured data collection and evaluation. (Ha)

  5. Polyunsaturated fatty acids and inflammation

    Calder Philip C

    2004-01-01

    The n-6 polyunsaturated fatty acid arachidonic acid gives rise to the eicosanoid family of inflammatory mediators (prostaglandins, leukotrienes and related metabolites) and through these regulates the activities of inflammatory cells, the production of cytokines and the various balances within the immune system. Fish oil and oily fish are good sources of long chain n-3 polyunsaturated fatty acids. Consumption of these fatty acids decreases the amount of arachidonic acid in cell membranes and ...

  6. Acid Rain Investigations.

    Hugo, John C.

    1992-01-01

    Presents an activity in which students investigate the formation of solid ammonium chloride aerosol particles to help students better understand the concept of acid rain. Provides activity objectives, procedures, sample data, clean-up instructions, and questions and answers to help interpret the data. (MDH)

  7. Acid Rain Classroom Projects.

    Demchik, Michael J.

    2000-01-01

    Describes a curriculum plan in which students learn about acid rain through instructional media, research and class presentations, lab activities, simulations, design, and design implementation. Describes the simulation activity in detail and includes materials, procedures, instructions, examples, results, and discussion sections. (SAH)

  8. The Acid Rain Game.

    Rakow, Steven J.; Glenn, Allen

    1982-01-01

    Provides rationale for and description of an acid rain game (designed for two players), a problem-solving model for elementary students. Although complete instructions are provided, including a copy of the game board, the game is also available for Apple II microcomputers. Information for the computer program is available from the author.…

  9. The Acid Rain Debate.

    Oates-Bockenstedt, Catherine

    1997-01-01

    Details an activity designed to motivate students by incorporating science-related issues into a classroom debate. Includes "The Acid Rain Bill" and "Position Guides" for student roles as committee members, consumers, governors, industry owners, tourism professionals, senators, and debate directors. (DKM)

  10. Hyaluronic Acid Assays

    Itenov, Theis S; Kirkby, Nikolai S; Bestle, Morten H;

    2015-01-01

    BACKGROUD: Hyaluronic acid (HA) is proposed as a marker of functional liver capacity. The aim of the present study was to compare a new turbidimetric assay for measuring HA with the current standard method. METHODS: HA was measured by a particle-enhanced turbidimetric immunoassay (PETIA) and enzyme...

  11. Koetjapic acid chloroform hemisolvate

    Z. D. Nassar

    2010-06-01

    Full Text Available The asymmetric unit of the title compound, C30H46O4·0.5CHCl3, consists of one koetjapic acid [systematic name: (3R,4aR,4bS,7S,8S,10bS,12aS-7-(2-carboxyethyl-3,4b,7,10b,12a-pentamethyl-8-(prop-1-en-2-yl-1,2,3,4,4a,4b,5,6,7,8,9,10,10b,11,12,12a-hexadecahydrochrysene-3-carboxylic acid] molecule and one half-molecule of chloroform solvent, which is disordered about a twofold rotation axis. The symmetry-independent component is further disordered over two sites, with occupancies of 0.30 and 0.20. The koetjapic acid contains a fused four-ring system, A/B/C/D. The A/B, B/C and C/D junctions adopt E/trans/cis configurations, respectively. The conformation of ring A is intermediate between envelope and half-chair and ring B adopts an envelope conformation whereas rings C and D adopt chair conformations. A weak intramolecular C—H...O hydrogen bond is observed. The koetjapic acid molecules are linked into dimers by two pairs of intermolecular O—H...O hydrogen bonds. The dimers are stacked along the c axis.

  12. Lactic acid and lactates

    Schreurs, V.V.A.M.

    2010-01-01

    This review aims to integrate the present state of knowledge on lactate metabolism in human and mammalian physiology as far as it could be subject to nutritional interventions. An integrated view on the nutritional, metabolic and physiological aspects of lactic acid and lactates might open a perspec

  13. Acid dip for dosemeter

    Background signal in a PTFE based dosemeter caused by impurities in the PTFE and in the active component such as lithium fluoride is substantially reduced by treating the dosemeter with acid. The optimum treatment involves use of hydrofluoric acid at room temperature for approximately one minute, followed by thorough washing with methanol, and finally drying. This treatment is best applied after the original manufacture of the dosemeters. It may also be applied to existing dosemeters after they have been in use for some time. The treatment produces a permanent effect in reducing both the light induced signal and the non-light induced signal. The process may be applied to all types of dosemeter manufactured from PTFE or other plastics or resins which are able to resist brief exposure to acid. The treatment works particularly well with dosemeters based on PTFE and lithium fluoride. It is also applicable to dosemeters based on calcium sulphate, lithium borate and magnesium borate. Acids which may be used include hydrofluoric, hydrochloric, nitric, phosphoric and sulphuric. (author)

  14. Accidents with sulfuric acid

    Rajković Miloš B.

    2006-01-01

    Full Text Available Sulfuric acid is an important industrial and strategic raw material, the production of which is developing on all continents, in many factories in the world and with an annual production of over 160 million tons. On the other hand, the production, transport and usage are very dangerous and demand measures of precaution because the consequences could be catastrophic, and not only at the local level where the accident would happen. Accidents that have been publicly recorded during the last eighteen years (from 1988 till the beginning of 2006 are analyzed in this paper. It is very alarming data that, according to all the recorded accidents, over 1.6 million tons of sulfuric acid were exuded. Although water transport is the safest (only 16.38% of the total amount of accidents in that way 98.88% of the total amount of sulfuric acid was exuded into the environment. Human factor was the common factor in all the accidents, whether there was enough control of the production process, of reservoirs or transportation tanks or the transport was done by inadequate (old tanks, or the accidents arose from human factor (inadequate speed, lock of caution etc. The fact is that huge energy, sacrifice and courage were involved in the recovery from accidents where rescue teams and fire brigades showed great courage to prevent real environmental catastrophes and very often they lost their lives during the events. So, the phrase that sulfuric acid is a real "environmental bomb" has become clearer.

  15. A Direct, Biomass-Based Synthesis of Benzoic Acid: Formic Acid-Mediated Deoxygenation of the Glucose-Derived Materials Quinic Acid and Shikimic Acid

    Arceo, Elena; Ellman, Jonathan; Bergman, Robert

    2010-05-03

    An alternative biomass-based route to benzoic acid from the renewable starting materials quinic acid and shikimic acid is described. Benzoic acid is obtained selectively using a highly efficient, one-step formic acid-mediated deoxygenation method.

  16. Origin of fatty acids

    The appearance of fatty acids and membranes is one of the most important events of the prebiotic world because genesis of life required the compartmentalization of molecules. Membranes allowed cells to become enriched with molecules relevant for their evolution and gave rise to gradients convertible into energy. By virtue of their hydrophobic/hydrophilic interface, membranes developed certain enzymatic activities impossible in the aqueous phase. A prebiotic cell is an energy unit but it is also an information unit. It has a past, a present and a future. The biochemistry of fatty acids involves acetylCoA, malonylCoA and an enzyme, acyl synthetase, which joins both molecules. After substitution of the acetyl group in place of the carboxyl group of malonyl derivatives, the chain is reduced and dehydrated to crotonyl derivatives. These molecules can again react with malonylCoA to form unsaturated chain; they can also undergo a new reduction step to form butyryl derivatives which can react with malonylCoA to form a longer aliphatic chain. The formation of malonylCoA consumes ATP. The reduction step needs NADPH and proton. Dehydration requires structural information because the reduction product is chiral (D configuration). It is unlikely that these steps were possible in a prebiotic environment. Thus we have to understand how fatty acids could appear in the prebiotic era. This hypothesis about the origin of fatty acids is based on the chemistry of sulfonium ylides and sulfonium salts. The most well-known among these molecules are S-melthyl-methionine and S-adenosyl methionine. The simplest sulfonium cation is the trimethylsulfonium cation. Chemists have evidence that these products can produce olefin when they are heated or flashed with UV light in some conditions. I suggest that these volatile products can allow the formation of fatty acids chains in atmospheric phase with UV and temperature using methanol as starting material. Different synthetic pathways will be

  17. Photostabilization of ascorbic acid with citric acid, tartaric acid and boric acid in cream formulations.

    Ahmad, I; Ali Sheraz, M; Ahmed, S; Shad, Z; Vaid, F H M

    2012-06-01

    This study involves the evaluation of the effect of certain stabilizers, that is, citric acid (CT), tartaric acid (TA) and boric acid (BA) on the degradation of ascorbic acid (AH(2) ) in oil-in-water cream formulations exposed to the UV light and stored in the dark. The apparent first-order rate constants (0.34-0.95 × 10(-3) min(-1) in light, 0.38-1.24 × 10(-2) day(-1) in dark) for the degradation reactions in the presence of the stabilizers have been determined. These rate constants have been used to derive the second-order rate constants (0.26-1.45 × 10(-2) M(-1) min(-1) in light, 3.75-8.50 × 10(-3) M(-1) day(-1) in dark) for the interaction of AH(2) and the individual stabilizers. These stabilizers are effective in causing the inhibition of the rate of degradation of AH(2) both in the light and in the dark. The inhibitory effect of the stabilizers is in the order of CT > TA > BA. The rate of degradation of AH(2) in the presence of these stabilizers in the light is about 120 times higher than that in the dark. This could be explained on the basis of the deactivation of AH(2) -excited triplet state by CT and TA and by the inhibition of AH(2) degradation through complex formation with BA. AH(2) leads to the formation of dehydroascorbic acid (A) by chemical and photooxidation in cream formulations. PMID:22296174

  18. Arterial Blood Carbonic Acid Inversely Determines Lactic and Organic Acids

    Aiken, Christopher Geoffrey Alexander

    2013-01-01

    Objective: To establish that arterial blood carbonic acid varies inversely with lactic acid in accordance with bicarbonate exchanging for lactate across cell membranes through the anion exchange mechanism to maintain the Gibbs-Donnan equilibrium.

  19. Dietary branched-chain amino acid (BCAA) and tumor growth

    Chan, W.; Baron, L.; Baron, P.; White, F.; Banks, W.L. Jr.

    1986-03-05

    The effects of high dietary BCAA on tumor growth was examined in adult male Fischer 344 rats inoculated with 10/sup 6/ viable MCA fibrosarcoma cells. Ten days after tumor inoculation, when tumors were of palpable size, rats were divided into two groups at random. The experimental(E) group was fed the AIN-76 diet supplemented with 4X the BCAA content of diet casein and the control(C) group was fed the AIN-76 made isonitrogenous with the E diet by glutamic acid supplementation. Five rats from each group were killed at days 0,3,6, and 9. Rats were injected with /sup 14/C-Tyrosine and /sup 3/H-Thymidine i.p. (2 and 4 uCi/100g BW, respectively) an hour before they were killed. The incorporation of /sup 14/C and /sup 3/H into the acid insoluble fraction of the tumor tissues samples were measured. Single cell suspension of tumor were prepared for cell cycle kinetics analysis using a Coulter EPICS IV flow microflorometer. The percentage of normal and hyperdiploid cells were analyzed. Results showed that both tumor size and weight were doubled at each time point the rats were killed. At day 0, the /sup 3/H and /sup 14/C incorporation were 32 +/- 10dpm and 27 +/- 4dpm/mg tumor, respectively. The /sup 3/H incorporation dropped in both diet groups at days 6 and 9 but the /sup 14/C incorporation showed a decrease only at day 9. These changes were statistically significant, P>0.05. No difference in the tumor growth parameters used in this study can be attributed to the high dietary BCAA.

  20. Mn substituted cobalt ferrites (CoMn{sub x}Fe{sub 2−x}O{sub 4} (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0)): As magnetically separable heterogeneous nanocatalyst for the reduction of nitrophenols

    Goyal, Ankita [Department of Chemistry, Panjab University, Chandigarh 160014 (India); Bansal, S. [DST, New Delhi (India); Kumar, V. [ICON Analytical Equipment(P) Ltd., Mumbai (India); Singh, Jagdish [IIC, IIT-Roorkee, Roorkee (India); Singhal, Sonal, E-mail: sonal1174@gmail.com [Department of Chemistry, Panjab University, Chandigarh 160014 (India)

    2015-01-01

    Graphical abstract: Catalytic activity of CoMn{sub x}Fe{sub 2−x}O{sub 4} (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) depends upon the distribution of cations among octahedral and tetrahedral sites and synergistic effect between the Co–Mn and Fe–Mn ions present in the surface sites. - Highlights: • Co–Mn ferrites as proficient catalysts for the reduction of nitrophenols. • Ferrite with composition CoMn{sub 0.2}Fe{sub 1.8}O{sub 4} was the best catalyst. • Synergistic effect existed between the Co, Fe and Mn ions. • Reduction followed pseudo first order kinetics. • Catalytic efficiency was related to cation distribution and synergistic effect. - Abstract: Manganese substituted cobalt ferrite nanoparticles with composition CoMn{sub x}Fe{sub 2−x}O{sub 4} (x = 0.0, 0.2, 0.4, 0.6, 0.8, 1.0) were synthesized using sol–gel technology and characterized using the Fourier transform infrared spectroscopy, high resolution transmission electron microscopy and X-ray diffraction techniques to confirm their formation. The prepared ferrite samples were explored as catalysts for the reduction of nitrophenols in the presence of NaBH{sub 4} as reducing agent. Pure cobalt ferrite was found to be inactive. However, catalytic efficiency enhanced dramatically with the introduction of Mn ions into the catalytically active surface sites (octahedral sites) of the cobalt ferrite lattice. This could be due to the presence of synergistic effect between the Co{sup 3+}, Mn{sup 3+} and Fe{sup 3+} ions present in the octahedral sites. CoMn{sub 02}Fe{sub 1.8}O{sub 4} ferrite was observed to have the best catalytic activity for the reduction of nitrophenols because of the highest Fe{sup 3+}/Mn{sup 3+} and Co{sup 3+}/Mn{sup 3+} ionic ratio at the catalytically active octahedral sites. The kinetics of reduction was studied and the reduction reaction followed pseudo first order kinetics. The rates of reduction of the three isomers of nitrophenols followed the order – 2-nitrophenol > 4

  1. Valence state of transition metal ions in Co{sub 1−x}Fe{sub x}Cr{sub 2}O{sub 4} (x = 0.1, 0.2, 0.5) ceramics from X-ray photoelectron and Mössbauer spectroscopy data

    Kochur, A.G., E-mail: agk@rgups.ru [Rostov State Transport University, 2 Narodnogo Opolcheniya, Rostov on Don 344038 (Russian Federation); Kozakov, A.T.; Googlev, K.A.; Kubrin, S.P.; Nikolskii, A.V. [Scientific Research Institute of Physics at Southern Federal University, 194 Stachki, Rostov on Don 344191 (Russian Federation); Torgashev, V.I. [Faculty of Physics, Southern Federal University, 5 Zorge, Rostov-on-Don 344090 (Russian Federation); Bush, A.A.; Shkuratov, V.Ya. [Moscow State Technical University of Radio Engineering, Electronics and Automation, Vernadskogo 78, Moscow 119454 (Russian Federation); Shevtsova, S.I. [Scientific Research Institute of Physics at Southern Federal University, 194 Stachki, Rostov on Don 344191 (Russian Federation)

    2015-07-05

    Highlights: • Ceramics Co{sub 1−x}Fe{sub x}Cr{sub 2}O{sub 4} (x = 0.1, 0.2, 0.5) are synthesized. • Valence state of 3d metal ions is studied with XPS and Mössbauer spectroscopy. • Ionic states of Co and Cr are 2+ and 3+; Fe ions are Fe{sup 2+} and Fe{sup 3+}, Fe{sup 3+} prevailing. • Relative Fe{sup 3+}/Fe{sup 2+} content grows with x; it is the same in the bulk and near surface. • Fe atoms substitute both Co and Cr atoms forming partly inverse spinel structure. - Abstract: Ceramics with nominal composition Co{sub 1−x}Fe{sub x}Cr{sub 2}O{sub 4} (x = 0.1, 0.2, 0.5) are synthesized via a solid state reaction method. Crystal structure of samples is studied with X-ray diffraction. Actual elemental composition is determined using X-ray microanalysis and X-ray photoelectron spectroscopy (XPS). Samples’ morphology is studied with scanning electron microscopy. Valence state of the Co, Fe and Cr ions is determined from 2p X-ray photoelectron spectra and Mössbauer spectra. XPS are assigned based on calculations with allowance for the multiplet splitting, crystal field, and the charge-transfer effects. Cobalt ions are found to be bivalent in tetrahedral coordination; chromium ions are trivalent in octahedral coordination. Fe ions are mostly in trivalent states, although Fe{sup 2+} ions are also present in significant amounts. Fe{sup 2+} ions are in tetrahedral coordination while Fe{sup 3+} ions occupy both tetrahedral and octahedral sites. Bulk and near-surface elemental compositions of the ceramic grains are noticeably different. Relative Fe{sup 3+}/Fe{sup 2+} contents are the same in the volume and at the surface of the samples; relative number of Fe{sup 3+} ions increases upon the increase of x. A model of partly inverse spinel structure is suggested where the atoms of iron substitute both Co and Cr atoms.

  2. Boswellic acid inhibits expression of acid sphingomyelinase in intestinal cells

    Duan Rui-Dong

    2009-12-01

    Full Text Available Abstract Background Boswellic acid is a type of triterpenoids with antiinflammatory and antiproliferative properties. Sphingomyelin metabolism generates multiple lipid signals affecting cell proliferation, inflammation, and apoptosis. Upregulation of acid sphingomyelinase (SMase has been found in several inflammation-related diseases such as inflammatory bowel diseases, atherosclerosis, and diabetes. Methods The present study is to examine the effect of 3-acetyl-11-keto-β-boswellic acids (AKBA, a potent boswellic acid, on acid SMase activity and expression in intestinal cells. Both transformed Caco-2 cells and non-transformed Int407 cells were incubated with AKBA. After incubation, the change of acid SMase activity was assayed biochemically, the enzyme protein was examined by Western blot, and acid SMase mRNA was quantified by qPCR. Results We found that AKBA decreased acid SMase activity in both intestinal cell lines in dose and time dependent manners without affecting the secretion of the enzyme to the cell culture medium. The effect of AKBA was more effective in the fetal bovine serum-free culture medium. Among different types of boswellic acid, AKBA was the most potent one. The inhibitory effect on acid SMase activity occurred only in the intact cells but not in cell-free extract in the test tubes. At low concentration, AKBA only decreased the acid SMase activity but not the quantity of the enzyme protein. However, at high concentration, AKBA decreased both the mass of acid SMase protein and the mRNA levels of acid SMase in the cells, as demonstrated by Western blot and qPCR, respectively. Under the concentrations decreasing acid SMase activity, AKBA significantly inhibited cell proliferation. Conclusion We identified a novel inhibitory effect of boswellic acids on acid SMase expression, which may have implications in human diseases and health.

  3. [Lipid synthesis by an acidic acid tolerant Rhodotorula glutinis].

    Lin, Zhangnan; Liu, Hongjuan; Zhang, Jian'an; Wang, Gehua

    2016-03-01

    Acetic acid, as a main by-product generated in the pretreatment process of lignocellulose hydrolysis, significantly affects cell growth and lipid synthesis of oleaginous microorganisms. Therefore, we studied the tolerance of Rhodotorula glutinis to acetic acid and its lipid synthesis from substrate containing acetic acid. In the mixed sugar medium containing 6 g/L glucose and 44 g/L xylose, and supplemented with acetic acid, the cell growth was not:inhibited when the acetic acid concentration was below 10 g/L. Compared with the control, the biomass, lipid concentration and lipid content of R. glutinis increased 21.5%, 171% and 122% respectively when acetic acid concentration was 10 g/L. Furthermore, R. glutinis could accumulate lipid with acetate as the sole carbon source. Lipid concentration and lipid yield reached 3.20 g/L and 13% respectively with the initial acetic acid concentration of 25 g/L. The lipid composition was analyzed by gas chromatograph. The main composition of lipid produced with acetic acid was palmitic acid, stearic acid, oleic acid, linoleic acid and linolenic acid, including 40.9% saturated fatty acids and 59.1% unsaturated fatty acids. The lipid composition was similar to that of plant oil, indicating that lipid from oleaginous yeast R. glutinis had potential as the feedstock of biodiesel production. These results demonstrated that a certain concentration of acetic acid need not to be removed in the detoxification process when using lignocelluloses hydrolysate to produce microbial lipid by R. glutinis. PMID:27349116

  4. Acetic acid extraction from aqueous solutions using fatty acids

    IJmker, H.M.; Gramblicka, M.; Kersten, S.R.A.; Ham, van der A.G.J.; Schuur, B.

    2014-01-01

    A major challenge for production of acetic acid via bio-based routes is cost-effective concentration and purification of the acetic acid from the aqueous solutions, for which liquid–liquid extraction is a possible method. A main challenge in extraction of acetic acid from dilute aqueous solutions is

  5. College Chemistry Students' Mental Models of Acids and Acid Strength

    McClary, LaKeisha; Talanquer, Vicente

    2011-01-01

    The central goal of this study was to characterize the mental models of acids and acid strength expressed by advanced college chemistry students when engaged in prediction, explanation, and justification tasks that asked them to rank chemical compounds based on their relative acid strength. For that purpose we completed a qualitative research…

  6. N-(3-Methylphenylsuccinamic acid

    B. Thimme Gowda

    2010-02-01

    Full Text Available In the crystal structure of the title compound, C11H13NO3, the conformations of the N—H and C=O bonds in the amide segment are anti to each other, and that of the amide H atom is anti to the meta-methyl group in the benzene ring. Furthermore, the conformations of the amide oxygen and the carbonyl O atom of the acid segment are also anti to the adjacent –CH2 groups. The C=O and O—H bonds of the acid group are syn to each other. In the crystal, the molecules are packed into infinite chains through intermolecular N—H...O and O—H...O hydrogen bonds.

  7. [Progress in glucaric acid].

    Qiu, Yuying; Fang, Fang; Du, Guocheng; Chen, Jian

    2015-04-01

    Glucaric acid (GA) is derived from glucose and commonly used in chemical industry. It is also considered as one of the "Top value-added chemicals from biomass" as carbohydrate monomers to produce various synthetic polymers and bioenergy. The demand for GA in food manufacture is increasing. GA has also attracted public attentions due to its therapeutic uses such as regulating hormones, increasing the immune function and reducing the risks of cancers. Currently GA is produced by chemical oxidation. Research on production of GA via microbial synthesis is still at preliminary stage. We reviewed the advances of glucaric acid applications, preparation and quantification methods. The prospects on production of GA by microbial fermentation were also discussed. PMID:26380405

  8. Studies on terreic acid.

    Yamamoto, H; Moriyama, K; Jinnouchi, H; Yagishita, K

    1980-03-01

    It was found that Aspergillus sp. No. Y-8980 which was isolated from a soil sample collected at Yoron Island in Kagoshima Prefecture belonged to Aspergillus terreus group by morphological observation. The active substance produced by the strain was obtained with a high yield in sucrose-yeast extract medium and extracted by chloroform, ethyl acetate and n-butanol at pH 2.4 approximately 2.6 from the culture broth. The substance was crystallized from chloroform and ethyl acetate after charcoal treatment of the crude crystal. From various physico-chemical properties, it was found that the substance was identical to terreic acid. Terreic acid showed MICs of 25 approximately 100 mcg/ml, 12.5 mcg/ml and 50 mcg/ml against Gram-positive and Gram-negative bacteria, Xanthomonas oryzae and Xanthomonas citri, respectively, but it did not control Pseudomonas, fungi and yeast. The LD50 was 75 mg/kg i.p. and i.v. in mice. With regards to the anti-tumor effect, the morphological degeneration on HeLa cells (human carcinoma cells) was observed in the concentrations of more than 6.25 mcg/ml of terreic acid. An increase of body weight of mice caused by Ehrlich ascites carcinoma cells was not definitely observed by the daily administration of 150 mcg of terreic acid per mouse for 8 consecutive days. Above showed the enough survival effect in dd mice implanted with Ehrlich ascites carcinoma cells, and the effect also was demonstrated by anatomies of mice. PMID:7190624

  9. Electrochemistry of nucleic acids

    Paleček, Emil; Bartošík, Martin

    2012-01-01

    Roč. 112, č. 6 (2012), s. 3427-3481. ISSN 0009-2665 R&D Projects: GA ČR(CZ) GAP301/11/2055; GA MŠk(CZ) ME09038; GA MŠk(CZ) LC06035 Institutional research plan: CEZ:AV0Z50040507; CEZ:AV0Z50040702 Keywords : nucleic acids electrochemistry * DNA biosensors * DNA damage Subject RIV: BO - Biophysics Impact factor: 41.298, year: 2012

  10. Bile acids for viral hepatitis

    Chen, Weikeng; Liu, J; Gluud, C

    2007-01-01

    Trials have assessed bile acids for patients with viral hepatitis, but no consensus has been reached regarding their usefulness.......Trials have assessed bile acids for patients with viral hepatitis, but no consensus has been reached regarding their usefulness....

  11. Pantothenic acid (Vitamin B5)

    ... niacinamide), vitamin B5 (pantothenic acid), vitamin B6 (pyridoxine), vitamin B12 (cyanocobalamin), and folic acid. However, some products do ... for dandruff, depression, diabetic nerve pain, enhancing immune function, improving athletic performance, tongue infections, gray hair, headache, ...

  12. [Possible ways of regulating detoxifying processes in the alcohol dehydrogenase reaction with pantothenic acid derivatives].

    Chernikevich, I P; Dorofeev, B F; Moĭseenok, A G

    1993-01-01

    Oxidation of derivatives and precursors of pantothenic acid was studied in alcohol dehydrogenase reactions. Despite the presence of free hydroxymethyl groups in a number of pantothenic acid derivatives only panthenol with Km = 8 x 10(-3) M was shown to serve as a substrate for alcohol dehydrogenase from horse liver tissue (EC 1.1.1.1) Pantethine, sodium phosphopantothenate, CoA and acetyl-CoA decreased the rate of ethanol oxidation, where pantethine and sodium phosphopantothenate were competitive inhibitors, while CoA and acetyl-CoA inhibited the enzyme noncompetitively Ki = 1.2 x 10(-2) M, 2.1 x 10(-2) M, 4.4 x 10(-4) M and 5.1 x 10(-4) M, respectively. Metabolic precursors, which were different from pantothenic acid in their structure, were not involved in the alcohol dehydrogenase reaction. Possible regulation of alcohol intoxication using derivatives and precursors of vitamin B3 is discussed. PMID:8511887

  13. ACID ROCK DRAINAGE

    Anca Ionce

    2010-10-01

    Full Text Available Acid rock drainage (ARD is an particularly important aspect for the evaluation of the decantation ponds’ safety, and which has been only once taken into consideration at the Tarnicioara decantation pond, year 2002, as a consequence of the apparition of a strong seepage on the deposit’s dump, that has chemically de-purified the water from the river Brateasa. We have observed ARD, which implies the release of acid solutions from the mining sterile deposits, from the underground mining works and from the quarries, in the following tailings dams: Tarnicioara, Valea Strajii, Poarta Veche- which served Tarniţa Preparation Enterprise and in the Dealu Negru and Paraul Cailor ponds- which, at their time served Fundu Moldovei Preparation Enterprise, both during the period of their functioning and the period after their closure. For the decantation pond Dumitrelu which served the Calimani preparation enterprise, acid seepages from the deposit were mentioned in a study made by SC ICPM SA Baia Mare in 1993. Subsequently to the closure of the objective such seepage did not take place anymore. Instead, by raining, there is a frequent plant sterile dragging from the contour retaining wall down to the trouble pond, situated upstream.

  14. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    NEENA GARG

    2015-01-01

    Lactic acid bacteria (LAB) is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LA...

  15. Retinoic acid and cancer treatment

    Chen, Mei-Chih; Hsu, Shih-Lan; Lin, Ho; Yang, Tsung-Ying

    2014-01-01

    Retinoic acid which belongs to the retinoid class of chemical compounds is an important metabolite of vitamin A in diets. It is currently understood that retinoic acid plays important roles in cell development and differentiation as well as cancer treatment. Lung, prostate, breast, ovarian, bladder, oral, and skin cancers have been demonstrated to be suppressed by retinoic acid. Our results also show that low doses and high doses of retinoic acid may respectively cause cell cycle arrest and a...

  16. Biological properties of lipoic acid

    Anna Bilska

    2002-06-01

    Full Text Available Lipoic acid is a prostetic group of H-protein of the glycine cleavage system and the dihydrolipoamide acyltransferases (E2 of the pyruvate, alpha-ketoglutarate and branched-chain alpha-keto acid dehydrogenase complexes. Lipoic acid and its reduced form, dihydrolipoic acid, reacts with oxygen reactive species. This paper reviews the beneficial effects in oxidative stress models or clinical conditions.

  17. Crystal Structure Refinement of MgNb 2O 6Columbite from Neutron Powder Diffraction Data and Study of the Ternary System MgO-Nb 2O 5-NbO, with Evidence of Formation of New Reduced Pseudobrookite Mg 5- xNb 4+ xO 15- δ(1.14≤ x≤1.60) Phases

    Pagola, S.; Carbonio, R. E.; Alonso, J. A.; Fernández-Díaz, M. T.

    1997-11-01

    The crystal structure of the columbite-type phase MgNb 2O 6has been refined from powder neutron diffraction data. The compound is orthorhombic, space group Pbcn(60), Z=4, with unit cell parameters a=14.1875(1), b=5.7001(1), c=5.0331(1) Å. The structure contains chains of NbO 6octahedra sharing edges along the caxis, which are arranged in double layers through common corners. The double layers, parallel to the bcplane, are connected via MgO 6octahedra sharing corners. This compound contains Nb 5+with electronic configuration d0. Attempts to obtain new materials with Nb in a mixed valence state were made in the ternary system MgO-Nb 2O 5-NbO. For molar ratios Mg:Nb=1:2 new pseudobrookite-type phases have been identified. They have the general composition Mg 5- xNb 4+ xO 15- δ, with xvalues ranging from 1.14 to 1.60. The compounds Mg 4Nb 2O 9- δ(corundum-type) and Mg 3Nb 6O 11were identified when the Mg:Nb ratio was 4:2. All the reduced materials were also characterized by thermogravimetric analysis.

  18. Speeds of sound in {l_brace}(1 - x)CH{sub 4} + xN{sub 2}{r_brace} with x = (0.10001, 0.19999, and 0.5422) at temperatures between 170 K and 400 K and pressures up to 30 MPa

    Estela-Uribe, J.F. [Facultad de Ingenieria, Universidad Javeriana-Cali, Calle 18, 118-250 Cali (Colombia); Trusler, J.P.M. [Department of Chemical Engineering, Imperial College London, London SW7 2AZ (United Kingdom)]. E-mail: m.trusler@imperial.ac.uk; Chamorro, C.R. [Grupo de Termodinamica y Calibracion (TERMOCAL), Dpto. Ingenieria Energetica y Fluidomecanica, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, E-47071 Valladolid (Spain); Segovia, J.J. [Grupo de Termodinamica y Calibracion (TERMOCAL), Dpto. Ingenieria Energetica y Fluidomecanica, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, E-47071 Valladolid (Spain); Martin, M.C. [Grupo de Termodinamica y Calibracion (TERMOCAL), Dpto. Ingenieria Energetica y Fluidomecanica, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, E-47071 Valladolid (Spain); Villamanan, M.A. [Grupo de Termodinamica y Calibracion (TERMOCAL), Dpto. Ingenieria Energetica y Fluidomecanica, E.T.S. de Ingenieros Industriales, Universidad de Valladolid, E-47071 Valladolid (Spain)

    2006-07-15

    The speed of sound in {l_brace}(1 - x)CH{sub 4} + xN{sub 2}{r_brace} has been measured with a spherical acoustic resonator. Two mixtures with x = (0.10001 and 0.19999) were studied along isotherms at temperatures between 220 K and 400 K with pressures up to 20 MPa; a few additional measurements at p = (25 and 30) MPa are also reported. A third mixture with x = 0.5422 was studied along pseudo-isochores at amount-of-substance densities between 0.2 mol . dm{sup -3} and 5 mol . dm{sup -3}. Corrections for molecular vibrational relaxation are discussed in detail and relaxation times are reported. The overall uncertainty of the measured speeds of sound is estimated to be not worse than {+-}0.02%, except for those measurements in the mixture with x = 0.5422 that lie along the pseduo-isochore at the highest amount-of-substance density. The results have been compared with the predictions of several equations of state used for natural gas systems.

  19. Sedimentation of sulfuric acid in acid tars from current production

    Denisova, T.L.; Frolov, A.F.; Aminov, A.N.; Novosel' tsev, S.P.

    1987-09-01

    Acid tars obtained in treating T-750, KhF-12, and I-8A oils were investigated for purposes of recovering sulfuric acid and asphalt binders from the compositions and of determining the effects of storage time on the recovery. The consumption and sedimentation levels of sulfuric acid during storage for different periods and at different temperatures were assessed. The characteristics of an asphalt binder obtained by neutralizing acid tar with a paste consisting of asphalts from deasphalting operations and slaked lime, followed by oxidation of the mixture with atmospheric air, were determined. The sulfuric acid recovered in the settling process could be burned in order to purify it of organic contaminants.

  20. Acids and bases solvent effects on acid-base strenght

    Cox, Brian G

    2013-01-01

    Acids and bases are ubiquitous in chemistry. Our understanding of them, however, is dominated by their behaviour in water. Transfer to non-aqueous solvents leads to profound changes in acid-base strengths and to the rates and equilibria of many processes: for example, synthetic reactions involving acids, bases and nucleophiles; isolation of pharmaceutical actives through salt formation; formation of zwitter- ions in amino acids; and chromatographic separation of substrates. This book seeks to enhance our understanding of acids and bases by reviewing and analysing their behaviour in non-aqueous solvents. The behaviour is related where possible to that in water, but correlations and contrasts between solvents are also presented.

  1. Estimation of the true ileal digestible lysine and sulfur amino acid requirement and comparison of the bioefficacy of 2-hydroxy-4-(methylthio)butanoic acid and DL-methionine in eleven- to twenty-six-kilogram nursery pigs.

    Yi, G F; Gaines, A M; Ratliff, B W; Srichana, P; Allee, G L; Perryman, K R; Knight, C D

    2006-07-01

    Three experiments were conducted to determine the true ileal digestible (TID) Lys and sulfur AA (SAA) requirement and to compare the bioefficacy of 2-hydroxy-4-(methylthio)butanoic acid (HMTBA) and dl-MET as Met sources in nursery pigs. Experiment 1 included 2 studies: 1 was 662 nursery pigs (Triumph 4 x PIC C22; initial BW 12.2 +/- 0.18 kg) allotted to 1 of 5 dietary treatments with TID Lys concentrations ranging from 1.10 to 1.50%; and the second study was 665 nursery pigs (Triumph 4 x PIC C22; initial BW 12.3 +/- 0.18 kg) allotted to 1 of 5 dietary treatments with TID SAA concentration ranging from 0.63 to 0.90%. In Exp. 2, 638 nursery pigs (Triumph 4 x PIC C22; initial BW 13.0 +/- 0.16 kg) were allotted to the same 5 SAA dietary treatments as in Exp. 1. In Exp. 3, 1,232 pigs (Triumph 4 x PIC C22; initial BW 11.0 +/- 0.30 kg) were allotted to 1 of 7 dietary treatments. The basal diet (diet 1) was supplemented with high concentrations of synthetic AA but no Met; this resulted in a dietary concentration of TID Lys of 1.30% and TID SAA of 0.50%. Diets 2 to 7 were the basal diet supplemented with 3 equimolar levels of HMTBA or dl-MET to provide TID SAA concentrations of 0.56, 0.62, and 0.68%, respectively. In Exp. 1, increasing TID Lys from 1.10 to 1.50% increased ADG (quadratic; P improved G:F (linear; P improved G:F (quadratic; P improvement of ADG (P < 0.001), ADFI (P < 0.05), and G:F (P < 0.001). The best fit comparison of HMTBA and dl-MET was determined by the Schwartz Bayesian Information Criteria index, which indicated the average relative efficacy of HMTBA vs. dl-MET was 111%, with 95% confidence interval of 83 to 138%, within the range of TID SAA tested. Thus, the TID Lys and SAA requirements of modern lean-genotype pigs from 11- to 26-kg were greater than the 1998 NRC recommendations, and both HMTBA and dl-MET as Met sources can supply equimolar amounts of Met activity. PMID:16775054

  2. An Umbrella for Acid Rain.

    Randal, Judith

    1979-01-01

    The Environmental Protection Agency has awarded several grants to study effects of and possible solutions to the problem of "acid rain"; pollution from atmospheric nitric and sulfuric acids. The research program is administered through North Carolina State University at Raleigh and will focus on biological effects of acid rain. (JMF)

  3. Excitatory amino acid receptor antagonists

    Johansen, T N; Frydenvang, Karla Andrea; Ebert, B;

    1997-01-01

    We have previously shown that (RS)-2-amino-2-(5-tert-butyl-3-hydroxyisoxazol-4-yl)acetic acid (ATAA) is an antagonist at N-methyl-D-aspartic acid (NMDA) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors. We have now resolved ATAA via diastereomeric salt formation...

  4. Pantothenic acid biosynthesis in zymomonas

    Tao, Luan; Tomb, Jean-Francois; Viitanen, Paul V.

    2014-07-01

    Zymomonas is unable to synthesize pantothenic acid and requires this essential vitamin in growth medium. Zymomonas strains transformed with an operon for expression of 2-dehydropantoate reductase and aspartate 1-decarboxylase were able to grow in medium lacking pantothenic acid. These strains may be used for ethanol production without pantothenic acid supplementation in seed culture and fermentation media.

  5. Acid Rain Limits Global Warming

    Will Knight; 张林玲

    2004-01-01

    @@ Acid rain restricts global warming by reducing methane① emissions from natural wetland areas, suggests a global climate study. Acid rain is the result of industrial pollution,which causes rainwater to carry small quantities of acidic compoumds② such as sulphuric and nitric acid③. Contaminated rainwater can upset rivers and lakes, killing fish and other organisms and also damage plants, trees and buildings.

  6. Self-neutralizing well acidizing

    Richardson, E.A.; Scheuerman, R.F.

    1974-07-30

    A process for acidizing a subterranean region by contacting it with an acidic solution is improved by dissolving in the solution a pH-increasing reactant that subsequently adjusts the pH of the solution to a selected relatively neutral value. Urea is an example of the acid neutralizer. (10 claims)

  7. Ionic liquid supported acid-catalysed esterification of lauric acid

    Ionic Liquid (IL) based on 1-n-butyl-3-methylimidazolium bis(trifluoro methylsulfonyl)imide (BMI.NTf2) under acidic condition was used as catalyst for the esterification reaction of fatty acid. Various acids namely sulphuric acid, perchloric acid, p-toulene sulphonic acid and various chloride salts such as zinc chloride (ZnCl2) and iron (III) chloride (FeCl3) immobilized in ionic liquid BMI.NTf2 gave acidic ILs. These acidic ILs were tested as catalysts for esterification reactions. Esterification of alcohol (methanol) with fatty acid (lauric acid) using ionic liquid BMI.NTf2 combined with H2SO4 (BMI.NTf2(H2SO4)) gave high activity (>85 %) and selectivity (100 %) observed over a period of 2 hours reaction with reaction temperature 70 degree Celsius. The ester became easily separated due to IL forming biphasic with product after the reaction where ester accumulated as the upper phase and IL with water produced after reaction at lower phase. Catalytic activities comparison also be studied between acidic ionic liquid BMI.NTf2 with acidic ionic liquid ChCl.2ZnCl2 and conventional acid catalyst. These ILs were characterised by using FTIR, NMR and TGA. Results from FTIR were showed no significant difference between ILs with ILs in acidic condition. The TGA curve show BMI.NTf2 thermals decomposition is ≥400 degree Celsius but when BMI.NTf2 combination with H2SO4, TGA curve show weight loss increase and becomes unstable. The advantages of ILs as catalyst are clean process and green chemistry due to its behaviour such as non-volatile, no loss of solvent through evaporation and reduced environmentally impact. This ILs-catalyst system can be recycle for further reaction. (author)

  8. Superprotonic Solid Acids Thermochemistry, Structure, and Conductivity

    Ikeda, Ayako

    In this work, in order to investigate the thermochemistry and property of the superprotonic solid acid compounds, the measurement methods were established for in situ observation, because superprotonic phases are neither stable at room temperature nor freezable to room temperature. A humidity-controlled TG, DSC and AC impedance measurement system, and high temperature stage for XRD were built for thermal analysis and characterization of the solid acid compounds. The thermodynamic and kinetics of the dehydration and hydration of CsH 2PO4 is investigated by TG, DSC, and XRD analysis. By making use of the enhanced kinetics afforded by SiO2, the phase boundary between CsH2PO4, CsPO3, and dehydrated liquid was precisely determined. The stability of CsH2PO4 and the liquid dehydrate, CsH2(1-x)PO4-x(l), were confirmed by the complete reversal of dehydration to recover these phases in the appropriate temperature and water partial pressure ranges. Rehydration and conversion of CsPO3(s) to CsH2PO4(s) occurs over a period of several hours, depending on temperature, water partial pressure, and morphology of the metaphosphate. High and small particles favor rapid dehydration, whereas the temperature dependence of the rehydration kinetics is nonmonotonic, reaching its fastest rate in the vicinity of the superprotonic transition. Doping Rb and K into CDP was examined and the stable region of Cs 1-xRbxH2PO4 and Cs1-xKxH2PO 4 are determined by in situ XRD and DSC measurement. Then the effects of doping to the structure and conductivity are discussed. It was found that Rb has whole-range solubility for both cubic and monoclinic CDP. Ts increases and Td decrease with Rb content. K has 27% solubility for cubic CDP, T s and Td decrease with K content. The eutectic temperature is 208 +/- 2°C. The lattice size of Rb- or K- doped CDP depends on the averaged cation size. Conductivity linearly decreases by dopant concentration. The impact of K doping is deeper than that of Rb for the

  9. Invasive cleavage of nucleic acids

    Prudent, James R. (Madison, WI); Hall, Jeff G. (Madison, WI); Lyamichev, Victor I. (Madison, WI); Brow, Mary Ann D. (Madison, WI); Dahlberg, James E. (Madison, WI)

    2002-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  10. Invasive cleavage of nucleic acids

    Prudent, James R.; Hall, Jeff G.; Lyamichev, Victor I.; Brow, Mary Ann D.; Dahlberg, James E.

    1999-01-01

    The present invention relates to means for the detection and characterization of nucleic acid sequences, as well as variations in nucleic acid sequences. The present invention also relates to methods for forming a nucleic acid cleavage structure on a target sequence and cleaving the nucleic acid cleavage structure in a site-specific manner. The structure-specific nuclease activity of a variety of enzymes is used to cleave the target-dependent cleavage structure, thereby indicating the presence of specific nucleic acid sequences or specific variations thereof.

  11. Tested Demonstrations: Color Oscillations in the Formic Acid-Nitric Acid-Sulfuric Acid System.

    Raw, C. J. G.; And Others

    1983-01-01

    Presented are procedures for demonstrating the production of color oscillations when nitric acid is added to a formic acid/concentrated sulfuric acid mixture. Because of safety considerations, "Super-8" home movie of the color changes was found to be satisfactory for demonstration purposes. (JN)

  12. Polyunsaturated fatty acids and inflammation

    Calder Philip C.

    2004-01-01

    Full Text Available The n-6 polyunsaturated fatty acid arachidonic acid gives rise to the eicosanoid family of inflammatory mediators (prostaglandins, leukotrienes and related metabolites and through these regulates the activities of inflammatory cells, the production of cytokines and the various balances within the immune system. Fish oil and oily fish are good sources of long chain n-3 polyunsaturated fatty acids. Consumption of these fatty acids decreases the amount of arachidonic acid in cell membranes and so available for eicosanoid production. Thus, n-3 polyunsaturated fatty acids act as arachidonic acid antagonists. Components of both natural and acquired immunity, including the production of key inflammatory cytokines, can be affected by n-3 polyunsaturated fatty acids. Although some of the effects of n-3 fatty acids may be brought about by modulation of the amount and types of eicosanoids made, it is possible that these fatty acids might elicit some of their effects by eicosanoid-independent mechanisms. Such n-3 fatty acid-induced effects may be of use as a therapy for acute and chronic inflammation, and for disorders that involve an inappropriately-activated immune response.

  13. Waste acid detoxification and reclamation

    Economically feasible processes that reduce the volume, quantity, and toxicity of metal-bearing waste acids by reclaiming, reusing, and recycling spent acids and metal salts are being developed and demonstrated. The acids used in the demonstrations are generated during metal-finishing operations used in nuclear fuel fabrication; HF-HNO3, HNO3, and HNO3-H2SO4 wastes result from Zr etching, Cu stripping, and chemical milling of U. At discharge, wastes contain high concentrations of acid and one major metal impurity. The waste minimization process used to reclaim acid from these three streams incorporates three processes for acid regeneration and reclamation. Normally, HNO3 remains in the bottoms when an aqueous acid solution is distilled; however, in the presence of H2SO4, HNO3 will distill to the overhead stream. In this process, nitrates and fluorides present as free acid and metal salts can be reclaimed as acid for recycle to the metal-finishing processes. Uranium present in the chemical milling solution can be economically recovered from distillation bottoms and refined. Using acid distillation, the volume of chemical milling solution discharged as waste can be reduced by as much as 60% depending on the H2SO4 concentration. A payback period of 2.2 years has been estimated for this process. The development and demonstration of precipitation and distillation processes for detoxification and reclamation of waste acid is supported by the US Department of Energy's Hazardous Waste Remedial Actions Program (HAZWRAP)

  14. Labeled bile acids

    A general short procedure for the introduction of 13C to the side chain of bile acids is described. Suitable (Z)-pregn-17(20)-enes are key intermediates, while the isotope is introduced by an ene reaction with [1,2,3-13C3]-methyl propiolate. For the labeling with tritium, the unlabeled product of the ene synthesis, a Δsup(5,16,22)-triene was saturated selectively at 16,17 and 22,23 with tritium gas. (author)

  15. N-(4-Isocyanophenylsuccinamic acid

    Lauren E. Burnham

    2012-07-01

    Full Text Available In the crystal structure of the title compound, C11H10N2O3, inversion-related molecules are connected by pairs of O—H...O hydrogen bonds. With the exception of the atoms in the carboxylic acid group, the non-H atoms are roughly coplanar with a maximum deviation from the mean plane of 0.270 (1 Å for the C atom to which the carboxylic group is attached. The C atom of the carboxylic group lies 1.730 (2 Å from the mean plane.

  16. Nucleic Acid Vaccines

    LU Shan

    2004-01-01

    @@ Anew method of immunization was discovered in the early 1990s. Several research groups independently demonstrated that direct inoculation of DNA plasmids coding for a specific protein antigen could elicit immune responses against that antigen[1-4].Since in theory the mRNA molecules also have the potential to be translated into the protein antigen, this vaccination approach was officially named by WHO as the nucleic acid vaccination even though the term DNA vaccine has been used more commonly in the literature. This novel approach is considered the fourth generation of vaccines after live attenuated vaccines, killed or inactivated vaccines and recombinant protein based subunit vaccines.

  17. Kinetics and Mechanism of Oxidation of Phenyl Acetic Acid and Dl-Mandelic Acid by Permanganate in Acid Medium

    B. Syama Sundar; P.S.Radhakrishna murti

    2014-01-01

    Kinetics of oxidation of phenyl acetic acid and DL- Mandelic acid by potassium permanganate in aqueous acetic acid and perchloric acid mixture reveals that the kinetic orders are first order in oxidant, first order in H+ and zero order in substrate for phenyl acetic acid. DL-Mandelic acid exhibits first order in oxidant and zero order in substrate. The results are rationalised by a mechanism involving intermediate formation of mandelic acid in case of Phenyl acetic acid and ester formation wi...

  18. Cryoprotection from lipoteichoic acid

    Rice, Charles V.; Middaugh, Amy; Wickham, Jason R.; Friedline, Anthony; Thomas, Kieth J.; Johnson, Karen; Zachariah, Malcolm; Garimella, Ravindranth

    2012-10-01

    Numerous chemical additives lower the freezing point of water, but life at sub-zero temperatures is sustained by a limited number of biological cryoprotectants. Antifreeze proteins in fish, plants, and insects provide protection to a few degrees below freezing. Microbes have been found to survive at even lower temperatures, and with a few exceptions, antifreeze proteins are missing. Survival has been attributed to external factors, such as the high salt concentration of brine veins and adhesion to particulates or ice crystal defects. We have discovered an endogenous cryoprotectant in the cell wall of bacteria, lipoteichoic acid biopolymers. Adding 1% LTA to bacteria cultures immediately prior to freezing provides 50% survival rate, similar to the results obtained with 1% glycerol. In the absence of an additive, bacterial survival is negligible as measured with the resazurin cell viability assay. The mode of action for LTA cryoprotection is unknown. With a molecular weight of 3-5 kDa, it is unlikely to enter the cell cytoplasm. Our observations suggest that teichoic acids could provide a shell of liquid water around biofilms and planktonic bacteria, removing the need for brine veins to prevent bacterial freezing.

  19. Growth of nitric acid hydrates on thin sulfuric acid films

    Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

    1994-05-01

    Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1 - 3 × 10-4 Torr H2O and 1 - 2.5 × 10-6 Torr HNO3) and subjected to cooling and heating cycles. FTIR spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

  20. Growth of nitric acid hydrates on thin sulfuric acid films

    Iraci, Laura T.; Middlebrook, Ann M.; Wilson, Margaret A.; Tolbert, Margaret A.

    1994-01-01

    Type I polar stratospheric clouds (PSCs) are thought to nucleate and grow on stratospheric sulfate aerosols (SSAs). To model this system, thin sulfuric acid films were exposed to water and nitric acid vapors (1-3 x 10(exp -4) Torr H2O and 1-2.5 x 10(exp -6) Torr HNO3) and subjected to cooling and heating cycles. Fourier Transform Infrared (FTIR) spectroscopy was used to probe the phase of the sulfuric acid and to identify the HNO3/H2O films that condensed. Nitric acid trihydrate (NAT) was observed to grow on crystalline sulfuric acid tetrahydrate (SAT) films. NAT also condensed in/on supercooled H2SO4 films without causing crystallization of the sulfuric acid. This growth is consistent with NAT nucleation from ternary solutions as the first step in PSC formation.

  1. Caro's acid - its introduction to uranium acid leaching in Australia

    After extensive testing and plant trials to establish the benefits of Caro's acid (H2SO5) as an alternative oxidant, Queensland Mines Limited decided to replace pyrolusite with Caro's acid in its acid leach uranium treatment plant at Nabarlek. The decision was based on the reagent savings and environmental gains associated with the removal of manganese from the process liquors, as well as the labour savings and improved oxidation reduction potential control possible in leaching using the Caro's acid system. Some changes in operating parameters were necessary with the introduction of Caro's acid to the treatment plant. Operating results have confirmed the relationship between oxidant demand and uranium content of ore established during the trials. Acid savings have been as predicted from the plant trials. The major saving has been of hydrated lime required for tailings neutralisation

  2. Solid acid catalysis from fundamentals to applications

    Hattori, Hideshi

    2014-01-01

    IntroductionTypes of solid acid catalystsAdvantages of solid acid catalysts Historical overviews of solid acid catalystsFuture outlookSolid Acids CatalysisDefinition of acid and base -Brnsted acid and Lewis acid-Acid sites on surfacesAcid strengthRole of acid sites in catalysisBifunctional catalysisPore size effect on catalysis -shape selectivity-Characterization of Solid Acid Catalysts Indicator methodTemperature programmed desorption (TPD) of ammoniaCalorimetry of adsorption of basic moleculesInfrare

  3. Synthesis and Characterisation of Addition Compounds of Pyridine Carboxylic Acid Hydrazides with Tin (IV Halides, Organotin (IV Halides and Thicyanates*

    R. C. Aggarwal

    1981-04-01

    Full Text Available Addition compounds of the compositions SnX/sub 4/.xL and R/sub n/SnX/sub 4-n/.xL where X=Cl/sup -/, Br/sup -/, I/sup -/, or (NCS/sup -/, R=phenyl or n-butyl, L = picolinic acid hydrazide (PH, nicotinic acid hydrazide (NH or isonicotinic acide hydrazide (INH, x=1 or 2 and n= 1,2 or 3 have been prepared and characterised with the help of elemental analysis, molar conductance, UV and IR spectral studies. All the adducts are nonionic as evidenced from their low molar conductances in DMF. UV and IR spectral studies show that NH and INH coordiante through carbonyl oxygen and terminal nitrogen; and (PH through carbonyl oxygen and ring nitrogen in monoadducts. All the three isometric pyridine carboxylic acid hydrazides are coordinated through pyridine nitrogen alone in the di-adducts. Octahedral geometry has been proposed for mono-as well as di-adducts.

  4. Amino Acid Decarboxylase Activity of Some Lactic Acid Bacteria

    Pelin ERTÜRKMEN; Turhan, İlkay; Öner, Zübeyde

    2015-01-01

    Microorganisms which have decarboxylase activity can form biogenic amine by enzymatic decarboxylation of amino acids in foods. Histamine poisoning results from consumption of foods typically certain types of fish and cheeses that contain unusually high levels of histamine. Therefore, decarboxylase activity is an important problem at the selection of lactic acid bacteria as a starter culture in fermented products. In this study, decarboxylase activities of 161 lactic acid bacteria (LAB) strain...

  5. Synthesis of stearic acid triethanolamine ester over solid acid catalysts

    Tao Geng; Qiu Xiao Li; Ya Jie Jiang; Wei Wang

    2010-01-01

    The synthesis of stearic acid triethanolamine ester over solid acid catalysts was investigated.The results showed that the catalytic activity and selectivity of zirconium sulfate supported on SBA-15(6)(pore diameter 6 nm)is better than that of commonly used hypophosphorous acid,zirconium sulfate supported on MCM-41 and zirconium sulfate supported on SBA-15(9)(pore diameter 9 nm).

  6. Bile acid interactions with cholangiocytes

    Xuefeng Xia; Heather Francis; Shannon Glaser; Gianfranco Alpini; Gene LeSage

    2006-01-01

    Cholangiocytes are exposed to high concentrations of bile acids at their apical membrane. A selective transporter for bile acids, the Apical Sodium Bile Acid Cotransporter (ASBT) (also referred to as Ibat; gene name Slc10a2)is localized on the cholangiocyte apical membrane. On the basolateral membrane, four transport systems have been identified (t-ASBT, multidrug resistance (MDR)3,an unidentified anion exchanger system and organic solute transporter (Ost) heteromeric transporter, OstαOstβ. Together, these transporters unidirectionally move bile acids from ductal bile to the circulation. Bile acids absorbed by cholangiocytes recycle via the peribiliaryplexus back to hepatocytes for re-secretion into bile.This recycling of bile acids between hepatocytes and cholangiocytes is referred to as the cholehepatic shunt pathway. Recent studies suggest that the cholehepatic shunt pathway may contribute in overall hepatobiliary transport of bile acids and to the adaptation to chronic cholestasis due to extrahepatic obstruction. ASBT is acutely regulated by an adenosine 3', 5'-monophosphate (cAMP)-dependent translocation to the apical membrane and by phosphorylation-dependent ubiquitination and proteasome degradation. ASBT is chronically regulated by changes in gene expression in response to biliary bile acid concentration and inflammatory cytokines.Another potential function of cholangiocyte ASBT is to allow cholangiocytes to sample biliary bile acids in order to activate intracellular signaling pathways. Bile acids trigger changes in intracellular calcium, protein kinase C (PKC), phosphoinositide 3-kinase (PI3K), mitogenactivated protein (MAP) kinase and extracellular signalregulated protein kinase (ERK) intracellular signals.Bile acids significantly alter cholangiocyte secretion,proliferation and survival. Different bile acids have differential effects on cholangiocyte intracellular signals,and in some instances trigger opposing effects on cholangiocyte secretion

  7. Synthesis and soft magnetic properties of Zn{sub 0.8−x}Ni{sub x}Mg{sub 0.1}Cu{sub 0.1}Fe{sub 2}O{sub 4} (x = 0.0−0.8) ferrites prepared by sol–gel auto-combustion method

    Satalkar, M., E-mail: satalkar.manvi@gmail.com [School of Physics, D. A. University, Khandwa Road Campus, Indore 452001 (India); Kane, S.N., E-mail: kane_sn@yahoo.com [School of Physics, D. A. University, Khandwa Road Campus, Indore 452001 (India); Ghosh, A. [School of Physics, D. A. University, Khandwa Road Campus, Indore 452001 (India); Ghodke, Nandkishor [UGC-DAE Consortium for Scientific Research, University Campus, Khandwa Road, Indore 452001 (India); Barrera, G. [INRIM, Electromagnetism Division, Strada Delle Cacce 91, I-10135 Torino (Italy); Università degli Studi di Torino, via P. Giuria 7, 10125 Torino (Italy); Celegato, F.; Coisson, M.; Tiberto, P.; Vinai, F. [INRIM, Electromagnetism Division, Strada Delle Cacce 91, I-10135 Torino (Italy)

    2014-12-05

    Highlights: • Ni2+ occupies A and B site, when Zn2+ is fully replaced by Ni2+, it goes to A site. • Change in distribution of cations has significant effect on magnetic properties. • Highest Ms value of 25.04 emu/g, was obtained for x = 0.60. - Abstract: Single phase nanocrystalline Zn{sub 0.8−x}Ni{sub x}Mg{sub 0.1}Cu{sub 0.1}Fe{sub 2}O{sub 4} (x = 0.0−0.8), were synthesized by sol–gel auto-combustion method without post-preparation treatment and, effect of Ni content on structural and magnetic properties is studied by X-ray diffraction (XRD), magnetic measurements and cation distribution. Scherrer’s grain diameter range between 23.5 and 35.1 nm. Experimental and theoretical lattice parameter values suggest that the estimated cation distribution is close to the real distribution. Change in Ni-content leads to variation in cation distribution at site A and B. Ni{sup 2+} ions occupy both A and B site, but when Zn{sup 2+} is fully replaced by Ni{sup 2+}, it totally goes to A site. Both coercivity measured at 50 Hz and quasi static coercivity value is found to increase with nickel content. Same trend is observed for anisotropy constant values. Best magnetization value of 25.04 emu/g was obtained for the specimen with x = 0.60. Variation of magnetic properties and other parameters (obtained via cation distribution) can be understood in terms of observed changes in distribution of cation(s) on A and B site.

  8. Relação cinemática em um trator 4x2 com tração dianteira auxiliar equipado com pneus radiais na eficiência de tração Kinematic relation on radial tires in a front wheel assist tractor on traction efficience

    Mauro Fernando Ferreira

    2000-12-01

    Full Text Available Diferentes combinações de pressões internas dos pneus do trator pode afetar a interferência entre eixos motrizes dos tratores agrícolas, principalmente com pneus do tipo radial. Um trator 4x2 com tração dianteira auxiliar foi analisado quanto a seu desempenho em tração. Pneus de carcaça radial com diferentes pressões internas foram utilizados, com o objetivo de variar as relações cinemá ticas entre os eixos. Mediram-se o patinamento das rodas dianteiras e traseiras, a resistência ao rolamento e a força de tração, em duas condições de solo (firme e solto. Os resultados obtidos permitiram verificar que a eficiência de tração não foi significativamente influenciada pela variação das relações cinemáticas de 0,962 a 1,102. As máximas eficiências de tração ocorreram com relaçõ es cinemáticas variáveis dentro da faixa estudada e de acordo com as cargas impostas à barra de tração.Different combinations of tractor tire inflating pressure may affect interference between tractor axles, mainly with radial tires type. A front wheel assist tractor was studied in its traction performance. Radial tires with different inflation pressure were used, changing kinematic relations between axles. The measured parameters were: front and rear slip, rolling resistence and drawbar pull in two soil conditions (firm and loose. The results indicate that traction efficience was not significantly influenced by kinematic relations variation between 0.962 to 1.102. The maximum traction efficiency ocurred within the range studied and according to drawbar pull.

  9. Electrochemical properties of vanadium-substituted lithium silicate materials Li2+xFe0.5-x/2Mn0.5-x/2Si1-xVxO4 (x = 0, 0.1, 0.2, 0.3 and 0.4) for lithium-ion battery cathodes

    Toyama, Tatsuya; Takahashi, Shin

    2015-10-01

    Vanadium-substituted LiFe0.5Mn0.5SiO4 cathode material for Li-ion batteries is synthesized by solid state reaction, and the effect of V-substitution on the material is investigated by X-ray diffraction and charge-discharge tests. X-ray diffraction patterns seem to indicate that V+5 is substituted for Si4+ in Li2+xFe0.5-x/2Mn0.5-x/2Si1-xVxO4 (x = 0, 0.1, 0.2, 0.3, 0.4) by maintaining electroneutrality. The substitution of V for Si in Li2Fe0.5Mn0.5SiO4 increases the charge and discharge capacities as a cathode material of Li-ion batteries; Li2.2Fe0.4Mn0.4Si0.8V0.2O4 delivers an initial discharge capacity of 197 A h/kg, while Li2Fe0.5Mn0.5SiO4 delivers that of 134 A h/kg. The main reason for the high capacity with the V substitution for Si in Li2Fe0.5Mn0.5SiO4 is considered not due to the redox capacity of V but due to the lowering of the charge voltage, while, substituting a higher amount of V, with x over 0.2 in Li2+xFe0.5-x/2Mn0.5-x/2Si1-xVxO4, reduces capacity in accordance with theoretical capacity calculation. In order to confirm the V-substitution site exactly, however, strong evidence by Rietveld refinement is necessary, which is left as our urgent future work.

  10. Studies on structural and magnetic properties of ternary cobalt magnesium zinc (CMZ) Co0.6-xMgxZn0.4 Fe2O4 (x = 0.0, 0.2, 0.4, 0.6) ferrite nanoparticles

    In this paper we report the variation in structural and magnetic properties of ternary ferrite nanoparticles (NPs) having stoichiometery Co0.6-xMgxZn0.4 Fe2O4 (x = 0.0, 0.2, 0.4, 0.6) and pure spinel ferrites MFe2O4 (M = Mg, Co). NPs with average particle diameter of 25–45 nm were synthesized employing self-propagating oxalyl dihydrazide - metal nitrate combustion method. The products were characterized using X-ray diffraction (XRD), Vibrating sample magnetometer (VSM), Transmission electron microscopy (TEM) and FT-IR spectroscopy. FT-IR spectral analysis revealed two bands centered at 560 and 440 cm−1 for tetrahedral and octahedral metal–oxygen bond stretching. Zinc doping caused red shift in the frequency band of tetrahedral M−O stretching. XRD powder diffraction patterns confirmed the formation of spinel ferrite nanoparticles, expansion of the lattice on zinc doping and enhancement of spinel phase purity in the doped ferrites. Cobalt ferrite displayed lowering of the magnetic parameters on zinc doping which further decreased in ternary ferrites Co0.6-xMgxZn0.4Fe2O4 on replacing cobalt ions with non-magnetic magnesium ions up to x = 0.4. At x = 0.6 reverse trend was observed and Ms was enhanced. Magnesium zinc ferrite Mg0.6Zn0.4 Fe2O4 with high value of Ms was obtained. Combustion process employed in the present studies serves as a low temperature facile route for the synthesis and structural analysis of ternary doped ferrite nanoparticles. - Highlights: • Ternary doped cobalt magnesium zinc ferrite nanoparticles are synthesized. • FT-IR displayed red shift in tetrahedral stretching band on Zinc doping. • Expansion of lattice and enhancement of spinel phase purity on zinc doping. • The variation in saturation magnetization (Ms) on doping is explained

  11. Molecular Simulation of Naphthenic Acid Removal on Acidic Catalyst Ⅱ. Experimental results of catalytic decarboxylation over acidic catalysts

    Fu Xiaoqin; Tian Songbai; Hou Shuandi; Longjun; Wang Xieqing

    2008-01-01

    The energy barriers of thermal decarboxylation reactions of petroleum acids and catalytic decarboxylation reactions of Br(o)nsted acid and Lewis acid were analyzed using molecular simulation technology.Compared with thermal decarboxylation reactions of petroleum acids, the decarboxylation reactions by acid catalysts were easier to occur. The decarboxylaton effect by Lewis acid was better than Br(o)nsted acid. The mechanisms of catalytic decarboxylation over acid catalyst were also verified by experiments on a fixed bed and a fluidized bed, the experimental results showed that the rate of acid removal could reach up to 97% over the acidic catalyst at a temperature above 400℃.

  12. Halogenated fatty acids

    Mu, Huiling; Sundin, Peter; Wesén, Clas

    1997-01-01

    bound in different lipids. For the detection and identification of individual, halogenated fatty acid methyl esters (FAMEs) liberated from the lipids, gas chromatography (GC) has been employed together with detection methods such as electron capture detection, electrolytic conductivity detection (ELCD......), atomic emission spectrometry, and mass spectrometry. For most environmental samples, chlorinated FAMEs must be enriched prior to GC. ELCD is a useful detection method for indicating halogenated FAMEs in the chromatograms, and tentative identification of the halogenated species can be obtained by...... calculation of retention indices. For closer identification of halogenated FAMEs, mass spectrometry (MS) is very useful, in particular when employing the chemical ionisation mode. MS identification, however, is highly facilitated if halogenated species are first indicated by element-selective methods....

  13. Inflammation but no DNA (deoxyribonucleic acid) damage in mice exposed to airborne dust from a biofuel plant

    Madsen, Anne Mette; Saber, Anne Thoustrup; Nordly, Pernille;

    2008-01-01

    Objectives Particles in ambient air are associated with such health effects as lung diseases and cancer of the lung. Exposure to bioaerosols has been found to be associated with respiratory symptoms. The toxic properties of exposure to combustion and bioaerosol particles from biofuel plants have...... not been studied in detail. This study investigated whether exposure to dust from biofuel plants induces DNA (deoxyribonucleic acid) damage and inflammation in exposed mice. Methods DNA damage and inflammation were evaluated in mice exposed through the intratracheal installation of airborne dust...... collected at a biofuel plant at the straw storage hall and in the boiler room. The mice were given either a single dose of dust (18 or 54 mu g) or four doses of 54 mu g on each of four consecutive days. Control mice were exposed to a 0.9% sodium chloride solution. Results In the mice exposed to 4 x 54 mu g...

  14. Polyunsaturated Fatty Acids in Children

    Lee, Ji-Hyuk

    2013-01-01

    Polyunsaturated fatty acids (PUFAs) are the major components of brain and retina, and are the essential fatty acids with important physiologically active functions. Thus, PUFAs should be provided to children, and are very important in the brain growth and development for fetuses, newborn infants, and children. Omega-3 fatty acids decrease coronary artery disease and improve blood flow. PUFAs have been known to have anti-inflammatory action and improved the chronic inflammation such as auto-im...

  15. Allelopathic Interactions Involving Phenolic Acids

    Blum, U.

    1996-01-01

    A major concern regarding allelopathic interactions involving phenolic acids in no-till systems pertains to the fact that concentrations of individual phenolic acids recoverable from field soils are well below levels required for inhibition of germination and seedling growth in laboratory bioassays. Field soils contain a variety of phenolic acids as well as other toxic and nontoxic organic compounds that are available to interact with seeds and roots; whereas in laboratory bioassays, with few...

  16. Fatty acid biosynthesis in actinomycetes

    Gago, Gabriela; Diacovich, Lautaro; Arabolaza, Ana; Tsai, Shiou-Chuan; Gramajo, Hugo

    2011-01-01

    All organisms that produce fatty acids do so via a repeated cycle of reactions. In mammals and other animals, these reactions are catalyzed by a type I fatty acid synthase (FAS), a large multifunctional protein to which the growing chain is covalently attached. In contrast, most bacteria (and plants) contain a type II system in which each reaction is catalyzed by a discrete protein. The pathway of fatty acid biosynthesis in Escherichia coli is well established and has provided a foundation fo...

  17. Kojic acid in organic synthesis

    ZIRAK, MARYAM; Eftekhari-Sis, Bagher

    2015-01-01

    The reactions of kojic acid in organic synthesis are reviewed. The aim of this review is to cover the literature up to the end of 2014, showing the distribution of publications involving kojic acid chemistry in the synthesis of various pyrone containing compounds, pyridine and pyridone heterocycles, and also other organic compounds. First, introductory text about the preparation, biological, and industrial applications, and the chemical properties of kojic acid is given. Then its uses in orga...

  18. [Total synthesis of nordihydroguaiaretic acid].

    Wu, A X; Zhao, Y R; Chen, N; Pan, X F

    1997-04-01

    beta-Keto ester(5) was obtained from vanilin through etherification, oxidation and condensation with acetoacetic ester, (5) on oxidative coupling reaction by NaOEt/I2 produced dimer (6) in high yield. Acid catalyzed cyclodehydration of (6) gave the furan derivative(7), and by a series of selective hydrogenation nordihydroguaiaretic acid, furoguaiacin dimethyl ether and dihydroguaiaretic acid dimethyl ether were synthesized. PMID:11499030

  19. ACETIC ACID AND A BUFFER

    2009-01-01

    The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent.......The present invention relates to a composition comprising : a) 0.01-20% wt/wt acetic acid and b) a physiologically tolerable buffer capable of maintaining acetic acid at a pH in the range of 2-7; and use of such a composition as an antimicrobial agent....

  20. Valproic Acid Induced Hyperammonaemic Encephalopathy

    Objective: To observe clinical and laboratory features of valproic acid-induced hyperammonaemic encephalopathy in patients taking valproic acid. Methods: Observational study was conducted at the Neurology Department, Dow University of Health Sciences, Civil Hospital, Karachi, from February 26, 2010 to March 20, 2011. Ten patients on valproic acid therapy of any age group with idiopathic or secondary epilepsy, who presented with encephalopathic symptoms, were registered and followed up during the study. Serum ammonia level, serum valproic acid level, liver function test, cerebrospinal fluid examination, electroencephalogram and brain imaging of all the patients were done. Other causes of encephalopathy were excluded after clinical and appropriate laboratory investigations. Microsoft Excel 2007 was used for statistical analysis. Results: Hyperammonaemia was found in all patients with encephalopathic symptoms. Rise in serum ammonia was independent of dose and serum level of valproic acid. Liver function was also found to be normal in 80% (n=8) of the patients. Valproic acid was withdrawn in all patients. Three (30%) patients improved only after the withdrawal of valproic acid. Six (60%) patients improved after L-Carnitine replacement, one (10%) after sodium benzoate. On followup, serum ammonia had reduced to normal in five (50%) patients and to more than half of the baseline level in two (20%) patients. Three (30%) patients were lost to followup after complete clinical improvement. Conclusion: Within therapeutic dose and serum levels, valproic acid can cause symptomatic hyperammonaemia resulting in encephalopathy. All patients taking valproic acid presenting with encephalopathic symptoms must be monitored for the condition. (author)

  1. Peptide Nucleic Acids Having Amino Acid Side Chains

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary DNA and RNA strands more strongly than the corresponding DNA or RNA strands, and exhibit increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from a group consisting of...

  2. Are Strong Bronsted Acids Necessarily Strong Lewis Acids?

    Sen-Gupta, K; Roy, D R; Subramanian, V

    2006-01-01

    The Broensted and Lowry acid base theory is based on the capacity of proton donation or acceptance (in the presence or absence of a solvent) whereas the Lewis acid base theory is based on the propensity of electron pair acceptance or donation. We explore through DFT calculation the obvious question whether these two theories are in conformity with each other. We use pKa as the descriptor for the Broensted and Lowry acidity. The DFT descriptors like ionization potential, electron affinity, electronegativity, hardness and global electrophilicity are computed for 58 organic and inorganic acids. The fractional electron transfer, del(N) and the associated energy change, del(E) for the reaction of these acids with trimethyl amine (a strong base) are used as the possible descriptors for the Lewis acidity. A near exponential decrease in del(N) and (-del(E)) values is observed in general with an increase in pKa values. The findings reveal that a stronger Broensted acid in most cases behaves as a stronger Lewis acid as...

  3. Fatty Acid Desaturases, Polyunsaturated Fatty Acid Regulation, and Biotechnological Advances

    Je Min Lee

    2016-01-01

    Full Text Available Polyunsaturated fatty acids (PUFAs are considered to be critical nutrients to regulate human health and development, and numerous fatty acid desaturases play key roles in synthesizing PUFAs. Given the lack of delta-12 and -15 desaturases and the low levels of conversion to PUFAs, humans must consume some omega-3 and omega-6 fatty acids in their diet. Many studies on fatty acid desaturases as well as PUFAs have shown that fatty acid desaturase genes are closely related to different human physiological conditions. Since the first front-end desaturases from cyanobacteria were cloned, numerous desaturase genes have been identified and animals and plants have been genetically engineered to produce PUFAs such as eicosapentaenoic acid and docosahexaenoic acid. Recently, a biotechnological approach has been used to develop clinical treatments for human physiological conditions, including cancers and neurogenetic disorders. Thus, understanding the functions and regulation of PUFAs associated with human health and development by using biotechnology may facilitate the engineering of more advanced PUFA production and provide new insights into the complexity of fatty acid metabolism.

  4. Conjugated linoleic acid increases in milk from cows fed condensed corn distillers solubles and fish oil.

    Bharathan, M; Schingoethe, D J; Hippen, A R; Kalscheur, K F; Gibson, M L; Karges, K

    2008-07-01

    Twelve lactating Holstein cows were randomly assigned to 1 of 4 experimental diets in a replicated 4 x 4 Latin square design with 4-wk periods to ascertain the lactational response to feeding fish oil (FO), condensed corn distillers solubles (CDS) as a source of extra linoleic acid, or both. Diets contained either no FO or 0.5% FO and either no CDS or 10% CDS in a 2 x 2 factorial arrangement of treatments. Diets were fed as total mixed rations for ad libitum consumption. The forage to concentrate ratio was 55:45 on a dry matter basis for all diets and the diets contained 16.2% crude protein. The ether extract concentrations were 2.86, 3.22, 4.77, and 5.02% for control, FO, CDS, and FOCDS diets, respectively. Inclusion of FO or CDS or both had no effect on dry matter intake, feed efficiency, body weight, and body condition scores compared with diets without FO and CDS, respectively. Yields of milk (33.3 kg/d), energy-corrected milk, protein, lactose, and milk urea N were similar for all diets. Feeding FO and CDS decreased milk fat percentages (3.85, 3.39, 3.33, and 3.12%) and yields compared with diets without FO and CDS. Proportions of trans-11 C18:1 (vaccenic acid), cis-9 trans-11 conjugated linoleic acid (CLA; 0.52, 0.90, 1.11, and 1.52 g/100 g of fatty acids), and trans-10 cis-12 CLA (0.07, 0.14, 0.13, and 0.16 g/100 g of fatty acids) in milk fat were increased by FO and CDS. No interactions were observed between FO and CDS on cis-9 trans-11 CLA although vaccenic acid tended to be higher with the interaction. The addition of CDS to diets increased trans-10 C18:1. Greater ratios of vaccenic acid to cis-9 trans-11 CLA in plasma than in milk fat indicate tissue synthesis of cis-9 trans-11 CLA in the mammary gland from vaccenic acid in cows fed FO or CDS. Feeding fish oil at 0.5% of diet dry matter with a C18:2 n-6 rich source such as CDS increased the milk CLA content but decreased milk fat percentages. PMID:18565937

  5. A comparison of chromic acid and sulfuric acid anodizing

    Danford, M. D.

    1992-01-01

    Because of federal and state mandates restricting the use of hexavalent chromium, it was deemed worthwhile to compare the corrosion protection afforded 2219-T87 aluminum alloy by both Type I chromic acid and Type II sulfuric acid anodizing per MIL-A-8625. Corrosion measurements were made on large, flat 2219-T87 aluminum alloy sheet material with an area of 1 cm(exp 2) exposed to a corrosive medium of 3.5-percent sodium chloride at pH 5.5. Both ac electrochemical impedance spectroscopy and the dc polarization resistance techniques were employed. The results clearly indicate that the corrosion protection obtained by Type II sulfuric acid anodizing is superior, and no problems should result by substituting Type II sulfuric acid anodizing for Type I chromic acid anodizing.

  6. Carbonic Acid Retreatment of Biomass

    Baylor university

    2003-06-01

    This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. (1) Solidify the theoretical understanding of the binary CO{sub 2}/H{sub 2}O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. (2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. (3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. (4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. (5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for

  7. Carbonic Acid Pretreatment of Biomass

    G. Peter van Walsum; Kemantha Jayawardhana; Damon Yourchisin; Robert McWilliams; Vanessa Castleberry

    2003-05-31

    This project sought to address six objectives, outlined below. The objectives were met through the completion of ten tasks. 1) Solidify the theoretical understanding of the binary CO2/H2O system at reaction temperatures and pressures. The thermodynamics of pH prediction have been improved to include a more rigorous treatment of non-ideal gas phases. However it was found that experimental attempts to confirm theoretical pH predictions were still off by a factor of about 1.8 pH units. Arrhenius experiments were carried out and the activation energy for carbonic acid appears to be substantially similar to sulfuric acid. Titration experiments have not yet confirmed or quantified the buffering or acid suppression effects of carbonic acid on biomass. 2) Modify the carbonic acid pretreatment severity function to include the effect of endogenous acid formation and carbonate buffering, if necessary. It was found that the existing severity functions serve adequately to account for endogenous acid production and carbonate effects. 3) Quantify the production of soluble carbohydrates at different reaction conditions and severity. Results show that carbonic acid has little effect on increasing soluble carbohydrate concentrations for pretreated aspen wood, compared to pretreatment with water alone. This appears to be connected to the release of endogenous acids by the substrate. A less acidic substrate such as corn stover would derive benefit from the use of carbonic acid. 4) Quantify the production of microbial inhibitors at selected reaction conditions and severity. It was found that the release of inhibitors was correlated to reaction severity and that carbonic acid did not appear to increase or decrease inhibition compared to pretreatment with water alone. 5) Assess the reactivity to enzymatic hydrolysis of material pretreated at selected reaction conditions and severity. Enzymatic hydrolysis rates increased with severity, but no advantage was detected for the use of carbonic

  8. Ghrelin and gastric acid secretion

    Koji Yakabi; Junichi Kawashima; Shingo Kato

    2008-01-01

    Ghrelin, a novel growth hormone-releasing peptide, was originally isolated from rat and human stomach. Ghrelin has been known to increase the secretion of growth hormone (GH), food intake, and body weight gain when administered peripherally or centrally. Ghrelin is also known to stimulate the gastric motility and the secretion of gastric acid. In the previous studies, the action of ghrelin on acid secretion was shown to be as strong as that of histamine and gastrin in-vivo experiment. In the studies, the mechanism for the action of ghrelin was also investigated. It was shown that vagotomy completely inhibited the action of ghrelin on the secretion of gastric acid suggesting that vagal nerve is involved in the mechanism for the action of ghrelin on acid secretion. As famotidine did not inhibit ghrelin-in-duced acid secretion in the study by Masuda et al, they concluded that histamine was not involved in the action of ghrelin on acid secretion. However, we have shown that famotidine completely inhibited ghrelin-induced acid secretion and histidine decarboxylase (HDC) mRNA was increased in gastric mucosa by ghrelin injection which is inhibited by vagotomy Our results indicate that histamine is involved in the action of ghrelin on acid secretion. Furthermore synergistic action of gastrin and ghrelin on gastric add secretion was shown. Although gastrin has important roles in postprandial secretion of gastric acid, ghrelin may be related to acid secretion during fasting period or at night. However, further studies are needed to elucidate the physiological role of ghrelin in acid secretion.

  9. Screening of lactic acid bacteria with high autolysis rate by N+-implantation

    In order to obtain lactic acid bacteria with high autolysis rate, Streptococcus salivarius ssp. thermophilus GS1 and Lactobacillus delbrueckii ssp. bulgaricus LD3 were mutated by 50 keV N+ ions implantation. The results indicated that the survival rate curve took a saddle shape in the range of 1 x 2.6 x 1013 ∼ 6 x 2.6 x 1013 and the total mutation rate was 57% ∼ 74%. The survival rate were 25% ∼ 33% on the suitable dose 4 x 2.6 x 1013 ion/cm2. Among the mutated strains with mutation rate in the range of 127.98% ∼-51.96%, the highest autolysis rate mutation strains were named LD3-A3 and GS1-B13. Compare with original strains, autolysis rates of LD3-A3 and GS1-B13 increased by 127.98% and 115.11% respectively. Fermentation properties of LD3-A3 and GS1-B13 were stable after 5 generation transfer inoculation. It indicates that the ion implantation technique is a feasible method in lactic acid bacteria breeding. (authors)

  10. Brief report on screening maize mutants with high inorganic phosphorus and low phytic acid content

    Four and two mutants with high inorganic phosphorus (IP) and low phytic acid (LP) content were identified from 'Huang C' and 'X178', the parents of the leading commercial hybrid maize cultivar 'Nongda 108', when the dry seeds were irradiated by 200 Gy Cobalt-60 gamma rays. The mutation frequencies for 'Huang C' and 'X178' in panical basis were 8.04 x 10-4 and 10.48 x 10-4, respectively. Compared to the wild type, the contents of total phosphorus (TP) were basically unchanged, phytic acid phosphorus (PAP) were detected with 79.09%, 66.06%, 47.58%, 43.94%, 70.00%, 48.28% decreases, and IP with 11.22, 9.91, 7.04, 6.43, 6.43, 4.33 times increases in six mutants, H-lpa1, H-lpa2, H-lpa3, H-lpa4, X-lpa1, X-lpa2, respectively. (authors)

  11. Origin of nucleic acids

    The appearance of nucleic acids is the first event after the birth of membranes which made it possible to assure the perenniality of information. The complexity of these molecules has led some scientists to propose that they were not prebiotic but rather derived a more simple and achiral primitive ancestor. This hypothesis suggests that ribose possesses properties that allowed the formation of certain polysaccharides which evolved to RNA. The first step of the hypothesis is the selection and concentration of ribofuranose. This sugar has chelating properties and its alpha-ribofuranose is favoured in the chelating position. The density of the sugar with a heavy cation is greater than water and thus the complex can escape the UV radiation at the surface of the ocean. The particularity of ribose is to be able to form a homochiral regular array of these basic chelating structures with pyrophosphite. These arrays evolve towards the formation of polysaccharides (poly ribose phosphate) which have a very organized structure. These polysaccharides in turn evolve to RNA by binding of adenine and deoxyguanine which are HCN derivatives that can react with the polysaccharides. The primitive RNA is methylated and oxidized to form prebiotic RNA with adenosine, cytidine, 7methyl-guanosine and ribothymidine as nucleic bases. The pathway of biosynthesis of DNA form RNA will be studied. I suggest that the appearance of DNA results form the interaction between prebiotic double stranded RNA and proteins. DNA could be a product of RNA degradation by proteins. The catabolism of RNA to DNA requires a source of free radicals, protons and hydrides. RNA cannot produce free radicals, which are provided by the phenol group of the amino acid tyrosien. Protons are provided by the medium and hydrides are provided by 7-methyl-guanosine which can fix hydrides coming from hydrogen gas and donate them for the transformation of a riboside to a deoxyriboside. This pathway suggests that DNA appeared at

  12. Cocrystals of fenamic acids with nicotinamide

    Fábián, László; Hamill, Noel; Eccles, Kevin S; Moynihan, Humphrey A; Maguire, Anita R.; McCausland, Linda; Lawrence, Simon E.

    2011-01-01

    Cocrystal formation between nicotinamide and five fenamic acid derivative drugs (flufenamic acid, niflumic tolfenamic acid, mefenamic acid and meclofenamic acid) was investigated using solution-based and solid-state preparation methods. It was anticipated that the well-known acid-aromatic nitrogen heterosynthon would provide a sufficient driving force for cocrystallization. The experiments yielded cocrystals with four of the five acids. Although the structures of these molecules are similar, ...

  13. Caffeic acid derivatives from Bupleurum chinense

    Haghi, G.; Hatami, A.; Mehran, M.; Hosseini, H

    2014-01-01

    In this study, caffeic acid (CA) and its three derivatives including 3-caffeoylquinic acid (3-CQA, neochlorogenic acid), 4-caffeoylquinic acid (4-CQA, cryptochlorogenic acid), and 5-caffeoylquinic acid (5-CQA, chlorogenic acid) were identified in Bupleurum chinense aerial parts using reverse-phase high-performance liquid chromatography (RP-HPLC) with photodiode array (PDA) detector, reference compounds and chemical reactions. Separation was performed on a C18 column using gradient elution wit...

  14. Acid Tests and Basic Fun.

    McBride, John W.

    1995-01-01

    Explores acids and bases using different indicators, such as turmeric, purple grape juice, and lichens. Because some of these indicators are not as sensitive as cabbage juice or litmus paper, determining to which acids and bases each indicator is sensitive presents an enjoyable, problem-solving challenge for students. Presents directions for…

  15. Acid Rain: The Scientific Challenge.

    Godfrey, Paul J.

    1991-01-01

    Documents the workings and findings of the Massachusetts Acid Rain Monitoring Project, which has pooled the volunteer efforts of more than 1,000 amateur and professional scientists since 1983. Reports on the origins of air pollution, the prediction of acid rain, and its effects on both water life and land resources. (JJK)

  16. Acid Rain: An Educational Opportunity?

    Marion, James I.

    1984-01-01

    Deals with how educators can handle the subject of acid rain; illustrates suggestions with experiences of grade nine students visiting Frost Valley Environmental Education Center (Oliverea, New York) to learn scientific concepts through observation of outdoor phenomena, including a stream; and discusses acid rain, pH levels, and pollution control…

  17. Acid Rain: What's the Forecast?

    Bybee, Rodger

    1984-01-01

    Discusses various types of acid rain, considered to be a century-old problem. Topics include: wet and dry deposition, effects on a variety of environments, ecosystems subject to detrimental effects, and possible solutions to the problem. A list of recommended resources on acid rain is provided. (BC)

  18. Pantothenic acid (Vitamin B5)

    ... suggests that taking pantothenic acid in combination with pantethine and thiamine does not improve muscular strength or ... Pantothenic Acid, D-Pantothenyl Alcohol, Dexpanthenol, Dexpanthénol, Dexpanthenolum, ... Pantothenate, Pantothénate, Pantothénate de Calcium, Pantothenol, ...

  19. Bile acids for viral hepatitis

    Chen, Weikeng; Liu, J; Gluud, C

    2003-01-01

    The viral hepatitides are common causes of liver diseases globally. Trials have assessed bile acids for patients with viral hepatitis, but no consensus was reached regarding their usefulness.......The viral hepatitides are common causes of liver diseases globally. Trials have assessed bile acids for patients with viral hepatitis, but no consensus was reached regarding their usefulness....

  20. Folic Acid: Data and Statistics

    ... acid fortification in the United States Recently, the American Journal of Preventive Medicine published a new study looking at the costs ... acid fortification and spina bifida in the U.S. American Journal of Preventive Medicine. January 2016 [epub ahead of print]. Related Links ...

  1. Kinetics and Mechanism of Oxidation of Phenyl Acetic Acid and Dl-Mandelic Acid by Permanganate in Acid Medium

    B.Syama Sundar

    2014-06-01

    Full Text Available Kinetics of oxidation of phenyl acetic acid and DL- Mandelic acid by potassium permanganate in aqueous acetic acid and perchloric acid mixture reveals that the kinetic orders are first order in oxidant, first order in H+ and zero order in substrate for phenyl acetic acid. DL-Mandelic acid exhibits first order in oxidant and zero order in substrate. The results are rationalised by a mechanism involving intermediate formation of mandelic acid in case of Phenyl acetic acid and ester formation with Mn (VII in case of DL-Mandelic acid. The following order of reactivity is observed: DL-Mandelic acid > Phenyl acetic acid. The high reactivity of DL-Mandelic acid over phenyl acetic acid may be due to different mechanisms operating with the two substrates and benzaldehyde is the final product in both the cases.

  2. Studies on structural and magnetic properties of ternary cobalt magnesium zinc (CMZ) Co{sub 0.6-x}Mg{sub x}Zn{sub 0.4} Fe{sub 2}O{sub 4} (x = 0.0, 0.2, 0.4, 0.6) ferrite nanoparticles

    Kaur, Manpreet, E-mail: manpreetchem@pau.edu; Jain, Palak; Singh, Mandeep

    2015-07-15

    In this paper we report the variation in structural and magnetic properties of ternary ferrite nanoparticles (NPs) having stoichiometery Co{sub 0.6-x}Mg{sub x}Zn{sub 0.4} Fe{sub 2}O{sub 4} (x = 0.0, 0.2, 0.4, 0.6) and pure spinel ferrites MFe{sub 2}O{sub 4} (M = Mg, Co). NPs with average particle diameter of 25–45 nm were synthesized employing self-propagating oxalyl dihydrazide - metal nitrate combustion method. The products were characterized using X-ray diffraction (XRD), Vibrating sample magnetometer (VSM), Transmission electron microscopy (TEM) and FT-IR spectroscopy. FT-IR spectral analysis revealed two bands centered at 560 and 440 cm{sup −1} for tetrahedral and octahedral metal–oxygen bond stretching. Zinc doping caused red shift in the frequency band of tetrahedral M−O stretching. XRD powder diffraction patterns confirmed the formation of spinel ferrite nanoparticles, expansion of the lattice on zinc doping and enhancement of spinel phase purity in the doped ferrites. Cobalt ferrite displayed lowering of the magnetic parameters on zinc doping which further decreased in ternary ferrites Co{sub 0.6-x}Mg{sub x}Zn{sub 0.4}Fe{sub 2}O{sub 4} on replacing cobalt ions with non-magnetic magnesium ions up to x = 0.4. At x = 0.6 reverse trend was observed and Ms was enhanced. Magnesium zinc ferrite Mg{sub 0.6}Zn{sub 0.4} Fe{sub 2}O{sub 4} with high value of Ms was obtained. Combustion process employed in the present studies serves as a low temperature facile route for the synthesis and structural analysis of ternary doped ferrite nanoparticles. - Highlights: • Ternary doped cobalt magnesium zinc ferrite nanoparticles are synthesized. • FT-IR displayed red shift in tetrahedral stretching band on Zinc doping. • Expansion of lattice and enhancement of spinel phase purity on zinc doping. • The variation in saturation magnetization (Ms) on doping is explained.

  3. Synthesis, magnetic and electric transport properties of mixed-valence manganites La{sub 0.5+x}Sr{sub 1.5−x}Mn{sub 0.5}Cr{sub 0.5}O{sub 4} (x=0.1, 0.2 and 0.3)

    Singh, Devinder, E-mail: drdssambyal@rediffmail.com; Mahajan, Arun

    2013-11-15

    A series of mixed-valence manganites La{sub 0.5+x}Sr{sub 1.5−x}Mn{sub 0.5}Cr{sub 0.5}O{sub 4} were synthesized by sol–gel method. Rietveld profile analysis shows that the phases crystallize with tetragonal unit cell in the space group I4/mmm. The lattice parameter c increases with increase in x while a parameter almost remains constant. The Weiss constant (θ) is positive for all the phases and found to increase with increase in x. The ferromagnetic interactions becomes more dominant with increase in x due to increase in Mn{sup 3+}–O–Mn{sup 4+} and Mn{sup 3+}–O–Cr{sup 3+} double exchange interactions. Resistivity can be described by the polaron hopping and the variable range hopping model. It was found that the transport mechanism is dominated by Mott's variable range hopping (VRH) model with a decrease of Mott localization energy with increase in x, which explains the decrease of resistivity. - Graphical abstract: Unit cell structure of La{sub 0.6}Sr{sub 1.4}Mn{sub 0.5}Cr{sub 0.5}O{sub 4}. Display Omitted Research highlights: • A series of K{sub 2}NiF{sub 4}-type compounds La{sub 0.5}+xSr{sub 1.5-x}Mn{sub 0.5}Cr{sub 0.5}O{sub 4} (x=0.1, 0.2, 0.3) have been synthesized. • The calculated tolerance factors confirms the tetragonal symmetry of the proposed phases. • The lattice parameter c increases with increase in x while a parameter almost remains constant. • The Weiss constant (θ) is positive for all the phases and found to increase with increase in x • The resistivity data has been best fitted using the Mott's variable range hopping (VRH) model.

  4. N-(3-Nitrophenylmaleamic acid

    B. Thimme Gowda

    2010-07-01

    Full Text Available In the title compound, C10H8N2O5, the molecule is slightly distorted from planarity. The molecular structure is stabilized by two intramolecular hydrogen bonds. The first is a short O—H...O hydrogen bond (H...O distance = 1.57 Å within the maleamic acid unit and the second is a C—H...O hydrogen bond (H...O distance = 2.24 Å which connects the amide group with the benzene ring. The nitro group is twisted by 6.2 (2° out of the plane of the benzene ring. The crystal structure manifests a variety of hydrogen bonding. The packing is dominated by a strong intermolecular N—H...O interaction which links the molecules into chains running along the b axis. The chains within a plane are further assembled by three additional types of intermolecular C—H...O hydrogen bonds to form a sheet parallel to the (overline{1}01 plane.

  5. Lactic Acid Bacteria

    ToddKlaenhammer

    2013-04-01

    Full Text Available Lactic acid bacteria (LAB are a diverse group of Gram-positive bacteria found in a vast array of environments including dairy products and the human gastrointestinal tract. In both niches, surface proteins play a crucial role in mediating interactions with the surrounding environment. The sortase enzyme is responsible for covalently coupling a subset of surface dependent proteins (SDPs to the cell wall of Gram-positive organisms through recognition of a conserved C-terminal LPXTG motif. Genomic sequencing of LAB and annotation has allowed for the identification of sortase and SDPs. Historically, sortase and SDPs were predominately investigated for their role in mediating pathogenesis. Identification of these proteins in LAB has shed light on their important roles in mediating nutrient acquisition through proteinase P as well as positive probiotic attributes including adhesion, mucus barrier function, and immune signaling. Furthermore, sortase expression signals in LAB have been exploited as a means to develop oral vaccines targeted to the gastrointestinal tract. In this review, we examine the collection of studies which evaluate sortase and SDPs in select species of dairy associated and health promoting LAB.

  6. Microfluidics in amino acid analysis.

    Pumera, Martin

    2007-07-01

    Microfluidic devices have been widely used to derivatize, separate, and detect amino acids employing many different strategies. Virtually zero-dead volume interconnections and fast mass transfer in small volume microchannels enable dramatic increases in on-chip derivatization reaction speed, while only minute amounts of sample and reagent are needed. Due to short channel path, fast subsecond separations can be carried out. With sophisticated miniaturized detectors, the whole analytical process can be integrated on one platform. This article reviews developments of lab-on-chip technology in amino acid analysis, it shows important design features such as sample preconcentration, precolumn and postcolumn amino acid derivatization, and unlabeled and labeled amino acid detection with focus on advanced designs. The review also describes important biomedical and space exploration applications of amino acid analysis on microfluidic devices. PMID:17542043

  7. Molten fatty acid based microemulsions.

    Noirjean, Cecile; Testard, Fabienne; Dejugnat, Christophe; Jestin, Jacques; Carriere, David

    2016-06-21

    We show that ternary mixtures of water (polar phase), myristic acid (MA, apolar phase) and cetyltrimethylammonium bromide (CTAB, cationic surfactant) studied above the melting point of myristic acid allow the preparation of microemulsions without adding a salt or a co-surfactant. The combination of SANS, SAXS/WAXS, DSC, and phase diagram determination allows a complete characterization of the structures and interactions between components in the molten fatty acid based microemulsions. For the different structures characterized (microemulsion, lamellar or hexagonal phases), a similar thermal behaviour is observed for all ternary MA/CTAB/water monophasic samples and for binary MA/CTAB mixtures without water: crystalline myristic acid melts at 52 °C, and a thermal transition at 70 °C is assigned to the breaking of hydrogen bounds inside the mixed myristic acid/CTAB complex (being the surfactant film in the ternary system). Water determines the film curvature, hence the structures observed at high temperature, but does not influence the thermal behaviour of the ternary system. Myristic acid is partitioned in two "species" that behave independently: pure myristic acid and myristic acid associated with CTAB to form an equimolar complex that plays the role of the surfactant film. We therefore show that myristic acid plays the role of a solvent (oil) and a co-surfactant allowing the fine tuning of the structure of oil and water mixtures. This solvosurfactant behaviour of long chain fatty acid opens the way for new formulations with a complex structure without the addition of any extra compound. PMID:27241163

  8. Short communication: assessment of the potential of cinnamaldehyde, condensed tannins, and saponins to modify milk fatty acid composition of dairy cows.

    Benchaar, C; Chouinard, P Y

    2009-07-01

    This study was conducted to determine whether feeding cinnamaldehyde (main component of cinnamon bark essential oil; Cinnamon cassia), condensed tannins from quebracho trees (Schinopsis balansae), or saponins from Yucca schidigera altered the milk fatty acid profile of dairy cows. For this purpose, 4 lactating cows were used in 4 x 4 Latin square design (28-d period) and fed a total mixed ration containing no additive (control), or supplemented with cinnamaldehyde (1 g/d; CIN), quebracho condensed tannin extract (150 g/d; 70% of tannins; QCT), or Yucca schidigera saponin extract (60 g/d; 10% of saponins; YSE). Results revealed no effects of feeding CIN or QCT on milk fatty acid profile. Supplementation with YSE resulted in some modifications of milk fatty acid profile as suggested by the reduced proportions of C6:0 (2.71 vs. 2.95%), C8:0 (1.66 vs. 1.89%), and trans-11 C18:1 (0.92 vs. 1.01%). Results show low potential of cinnamaldehyde, condensed tannins, and saponins to alter ruminal biohydrogenation process and modify the fatty acid profile of milk fat at the feeding rates used in this study. Further investigations are needed to determine the factors that limit the effects of these secondary metabolites on ruminal microbial populations involved in the biohydrogenation processes of unsaturated fatty acids. PMID:19528616

  9. Hypocholesterolemic Effects of Eicosapentaenoic Acid and Docosahexaenoic Acid in Rats

    KANAZAWA, Akio; TESHIMA, Shin-ichi; TOKIWA, Shigeru; IMATANAKA, Nobuya; カナザワ, アキオ; テシマ, シンイチ; トキワ, シゲル; イマタナカ, ノブヤ; 金沢, 昭夫; 手島, 新一; 常盤, 繁; 今田中, 伸哉

    1984-01-01

    Eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) methylesters (ME) were preparedfrom a squid-liver oil and their hypocholesterolemic activities examined with rats. The supplementof 0.3% EPA-ME to the diet containing 1.0% cholesterol and 4.0% butter as lipids reduced a serum-cholesterollevel markedly, whereas DHA-ME gave almost no effect on the serum-cholesterol level.Both EPA-ME and DHA-ME reduced the liver-cholesterol level as effectively as linoleic acid did.The supplement of smal...

  10. Analytical application of aminohydroxamic acids

    Anthranilic hydroxamic acid was prepared by coupling of methylanthranilate (prepared by esterification of anthranilic acid with methyl alcohol using the fisher-speir method) with freshly prepared hydroxylamine. The lignad was characterized by the usual reaction of hydroxamic acid with acidic V(V) and Fe(III) solutions that gives blood-red colour in amyl alcohol and deep-violet colour in aqueous solution, respectively. The absorbance of Fe(III)-hydroxamic acids complexes increases with increase of pH. In this study, the effect of pH on the absorbance of Fe(III)-anthranilic hydroxamic acid was in accordance with this trend. The maximum absorbance was obtained at pH 5.0 at maximum wavelength of 482 nm. For Cu(II)-anthranilic hydroxamic acid complex, the use of acidic basic pH lead to precipitation of Cu(II)-ligand complex. But when using buffer pH (acetic acid/sodium acetate) a clear green colour of Cu(II)-ligand complex was obtained. The maximum wavelength of 390 nm. V(V)-anthranilic hydroxamic acid complex was extracted in acidic medium in amyl alcohol at pH 2.0 because in aqueous solution V(V)-anthranilic hydroxamic acid complex has not clear colour. It was observed the the maximum extraction in acidic medium decrease sharply with the increasing of pH value. The maximum wavelength for maximum absorbance was recorded at 472 nm. V(V) interfered with determination of Fe(III)) above concentration of 2 ppm, whereas Cu(II) interferes slightly with the determination of Fe(III) ions even at a high concentration of the Cu(II) ions. Both Cu(II) and Ni(II) do not interfere with the determination of V(V) ions even at high concentrations, Fe(III) ion produced slight interference, while Mo(VI) ions have a pronounced interference. Both V(V) and Fe(III) ions interfered markedly with the determination of Cu(II) ions, and made impractical under conditions. However, the calibration curves for the three metal ions produced a practical linear dynamic range.(Author)

  11. The Property and Application of Arachidonic Acid

    王相勤; 姚建铭; 袁成凌; 王纪; 余增亮

    2002-01-01

    Arachidonic acid (AA) is one of the most important PUFAs (polyunsaturated fatty acids) in human body. A high-yield arachidonic acid-producing strain (mortierella alpina) was selected by ion implantation (the relative content of arachidonic acid is 70.2% among all fatty acids). This paper mainly introduced the structure, distribution, source, physiologic healthcare function and application of AA.

  12. The property and application of arachidonic acid

    Arachidonic acid (AA) is one of the most important PUFAs (polyunsaturated fatty acids) in human body. A high-yield arachidonic acid-producing strain (mortierella alpina) was selected by ion implantation (the relative content of arachidonic acid is 70.2% among all fatty acids). The author mainly introduced the structure, distribution, source, physiologic health care function and application of AA

  13. Diabetes and alpha lipoic acid

    IssyLaher

    2011-11-01

    Full Text Available Diabetes mellitus is a multi-faceted metabolic disorder where there is increased oxidative stress that contributes to the pathogenesis of this debilitating disease. This has prompted several investigations into the use of antioxidants as a complementary therapeutic approach. Alpha lipoic acid, a naturally occurring dithiol compound which plays an essential role in mitochondrial bioenergetic reactions, has gained considerable attention as an antioxidant for use in managing diabetic complications. Lipoic acid quenches reactive oxygen species, chelates metal ions, and reduces the oxidized forms of other antioxidants such as vitamin C, vitamin E and glutathione. It also boosts antioxidant defense system through Nrf2-mediated antioxidant gene expression and by modulation of peroxisome proliferator activated receptors-regulated genes. ALA inhibits nuclear factor kappa B and activates AMPK in skeletal muscles, which in turn have a plethora of metabolic consequences. These diverse actions suggest that a lipoic acid acts by multiple mechanisms, many of which have only been uncovered recently. In this review we briefly summarize the known biochemical properties of lipoic acid and then discussed the oxidative mechanisms implicated in diabetic complications and the mechanisms by which lipoic acid may ameliorate these reactions. The findings of some of the clinical trials in which lipoic acid administration has been tested in diabetic patients during the last 10 years are summarized. It appears that the clearest benefit of lipoic acid supplementation is in patients with diabetic neuropathy.

  14. Boronic acid-based autoligation of nucleic acids

    Barbeyron, R.; Vasseur, J.-J.; Smietana, M.;

    2013-01-01

    Abstract: The development of synthetic systems displaying dynamic and adaptive characteristics is a formidable challenge with wide applications from biotechnology to therapeutics. Recently, we described a dynamic and programmable nucleic acid-based system relying on the formation of reversible...

  15. Docosahexaenoic acid affects arachidonic acid uptake in megakaryocytes

    Schick, P.K.; Webster, P.

    1987-05-01

    Dietary omega 3 fatty acids are thought to prevent atherosclerosis, possibly by modifying platelet (PT) function and arachidonic acid (20:4) metabolism. The study was designed to determine whether omega 3 fatty acids primarily affect 20:4 metabolism in megakaryocytes (MK), bone marrow precursors of PT, rather than in circulating PT. MK and PT were isolated from guinea pigs and incubated with (/sup 14/C)-20:4 (0.13uM). Docosahexaenoic acid (22:6) is a major omega 3 fatty acid in marine oils. The incubation of MK with 22:6 (0.1, 1.0 uM) resulted in the decrease of incorporation of (/sup 14/C)-20:4 into total MK phospholipids, 16% and 41% respectively. Alpha-linolenic acid (18:3), a major omega 3 fatty acid present in American diets, had no effect on 20:4 uptake in MK. 22:6 primarily affected the uptake of (/sup 14/C)-20:4 into phosphatidylethanolamine (PE) and phosphatidylserine (PS) in MK. In MK, 22:6 (0.1, 1.0 uM) caused a decrease of incorporation of (/sup 14/C)-20:4 into PE, 21% and 55% respectively; a decrease into PS, 16% and 48% respectively; but only a decrease of 4% and 18%, respectively, into phosphatidylcholine; and a decrease of 3% and 21% into phosphatidylinositol 22:6 (3.0 uM) had no effect on the uptake of AA into PT phospholipids. The study shows that 22:6 has a selective effect on AA uptake in MK and that the acylation or transacylation of PE and PS are primarily affected. 22:6 and other marine omega 3 fatty acids appear to primarily affect megakaryocytes which may result in the production of platelets with abnormal content and compartmentalization of AA.

  16. Amino Acids from a Comet

    Cook, Jamie Elisla

    2009-01-01

    NASA's Stardust spacecraft returned samples from comet 81P/Wild 2 to Earth in January 2006. Examinations of the organic compounds in cometary samples can reveal information about the prebiotic organic inventory present on the early Earth and within the early Solar System, which may have contributed to the origin of life. Preliminary studies of Stardust material revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds (cometary- vs. terrestrial contamination) could not be identified. We have recently measured the carbon isotopic ratios of these amino acids to determine their origin, leading to the first detection of a coetary amino acid.

  17. PHARMACOLOGICAL ACTIVITIES OF PROTOCATECHUIC ACID.

    Khan, Abida Kalsoom; Rashid, Rehana; Fatima, Nighat; Mahmood, Sadaf; Mir, Sadullah; Khan, Sara; Jabeen, Nyla; Murtaza, Ghulam

    2015-01-01

    Protocatechuic acid (3,4-dihydroxybenzoic acid, PCA) is a simple phenolic acid. It is found in a large variety of edible plants and possesses various pharmacological activities. This article aims to review the modern trends in phytochemical isolation and extraction of PCA from plants and other natural resources. Moreover, this article also encompasses pharmacological and biological activities of PCA. It is well known to have anti-inflammatory, antioxidant, anti-hyperglycemia, antibacterial, anticancer, anti-ageing, anti-athro- genic, anti-tumoral, anti-asthma, antiulcer, antispasmodic and neurological properties. PMID:26647619

  18. Treatment of acid mine wastewaters

    Acid mine drainage often results from the oxidation sulfide minerals to form sulfuric acid. As a consequence, high concentrations of metals in the both the suspended and dissolved state result from the low pH water. This paper discusses several of the more common treatment methods for acid mine drainage including the use of chemical precipitation agents, pH correction agents, filtration methods, and biodegradation methods. Advanced treatment technologies are also briefly described and include microfiltration, reverse osmosis, ion exchange, and electrodialysis

  19. The importance of radiolabelling human granulocytes with 111In-tropolonate or 111In-2-mercaptopyridine-N-oxide in plasma containing acid-citrate-dextrose

    The effect of acid-citrate-dextrose (ACD) and heparin on the labelling efficiency (LE) and optimum concentration of ligand required to radiolabel human granulocytes in plasma with 111In-tropolonate or 111In-2-mercaptopyridine-N-oxide (111In-merc) has been measured. The concentrations of ligand (tropolone or merc) required for maximum cell labelling in plasma containing ACD were 4 x 10-4 M tropolone and 1 x 10-4 M merc, whereas using plasma containing heparin, the optimum concentrations were 10-fold higher, at 4 x 10-3 M and 1 x 10-3 M respectively. At the optimum ligand concentrations, the LE for 1 x 108 granulocytes labelled in plasma containing ACD was 90% using 111In-tropolonate and 82% using 111In-merc, whereas using plasma containing heparin they were 68% and only 20%, respectively. Addition of ACD to heparinised plasma abolished the necessity for more ligand and increased the LE to the same values as those for plasma containing ACD alone. These results clearly demonstrate that to obtain a high LE using the lowest possible concentrations of tropolone or merc, the granulocytes must be labelled in plasma containing ACD. (author)

  20. Macromolecular organic acids in the Murchison meteorite

    Watson, J.S.; Sephton, M.A.; Gilmour, I.

    2005-01-01

    This study has detected bound organic acids within the Murchison meteorite organic macromolecule. Benzoic acid was the most abundant compound; other abundant compounds include C1 and C2 benzoic acids. Their origin and significance will be discussed.

  1. Molar extinction coefficients of some fatty acids

    Sandhu, G.K.; Singh, K.; Lark, B.S.;

    2002-01-01

    ) and stearic acid (C18H36O2), has been measured at the photon energies 81, 356, 511, 662, 1173 and 1332 keV. Experimental values for the molar extinction coefficient, the effective atomic number and the electron density have been derived and compared with theoretical calculations. There is good......The attenuation of gamma rays in some fatty acids, viz. formic acid (CH2O2), acetic acid (C2H4O2), propionic acid (C3H6O2), butyric acid (C4H8O2), n-hexanoic acid (C6H12O2), n-caprylic acid (C8H16O2), lauric acid (C12H24O2), myristic acid (C14H28O2), palmitic acid (C16H32O2), oleic acid (C18H34O2...

  2. LACTIC ACID BACTERIA: PROBIOTIC APPLICATIONS

    NEENA GARG

    2015-10-01

    Full Text Available Lactic acid bacteria (LAB is a heterotrophic Gram-positive bacteria which under goes lactic acid fermentations and leads to production of lactic acid as an end product. LAB includes Lactobacillus, Leuconostoc, Pediococcus, Lactococcus and Streptococcus which are grouped together in the family lactobacillaceae. LAB shows numerous antimicrobial activities due to production of antibacterial and antifungal compounds such as organic acids, bacteriocins, diacetyl, hydrogen peroxide and reutrin. LAB are used as starter culture, consortium members and bioprotective agents in food industry that improve food quality, safety and shelf life. A variety of probiotic LAB species are available including Lactobacillus acidophilus, L. bulgaricus, L. lactis, L. plantarum, L. rhamnosus, L. reuteri, L. fermentum, Bifidobacterium longum, B. breve, B. bifidum, B. esselnsis, B. lactis, B. infantis that are currently recommended for development of functional food products with health-promoting capacities.

  3. Treatment of hydrofluoric acid burns

    Thiele, B.; Winter, U.J.; Mahrle, G.; Steigleder, G.K.

    1986-01-31

    A chemical-plant worker sustained hydrofluoric acid burns during cleaning procedures. Intra-arterial perfusion and intralesional injections of calcium gluconate solution prevented progression of the burns into deeper tissue layers.

  4. [Treatment of hydrofluoric acid burns].

    Thiele, B; Winter, U J; Mahrle, G; Steigleder, G K

    1986-01-31

    A chemical-plant worker sustained hydrofluoric acid burns during cleaning procedures. Intra-arterial perfusion and intralesional injections of calcium gluconate solution prevented progression of the burns into deeper tissue layers. PMID:3943470

  5. Main: Amino acid Analysis [KOME

    Full Text Available Amino acid Analysis UniProt search ... blastx result Result of blastx search ... against UniProt protein ... database kome_uniprot_search _blastx_result.zip kome_uniprot_search _blastx_resul ...

  6. Main: Amino acid Analysis [KOME

    Full Text Available Amino acid Analysis SwissProt search ... result Result of blastx search ... against SwissProt protein da ... tabase kome_swissprot_search _result.zip kome_swissprot_search _result ...

  7. Biotechnological production of citric acid

    Belén Max

    2010-12-01

    Full Text Available This work provides a review about the biotechnological production of citric acid starting from the physicochemical properties and industrial applications, mainly in the food and pharmaceutical sectors. Several factors affecting citric acid fermentation are discussed, including carbon source, nitrogen and phosphate limitations, pH of culture medium, aeration, trace elements and morphology of the fungus. Special attention is paid to the fundamentals of biochemistry and accumulation of citric acid. Technologies employed at industrial scale such as surface or submerged cultures, mainly employing Aspergillus niger, and processes carried out with Yarrowia lipolytica, as well as the technology for recovering the product are also described. Finally, this review summarizes the use of orange peels and other by-products as feedstocks for the bioproduction of citric acid.

  8. The Nucleic Acid Database (NDB)

    Berman, H. M.; Feng, Z.; Schneider, Bohdan; Westbrook, J.; Zardecki, C.

    Vol. F. Dordrecht : Kluwer Academic, 2001 - (Rossmann, M.; Arnold, E.), s. 657-682 Institutional research plan: CEZ:AV0Z4040901 Keywords : database * nucleic acid Subject RIV: CF - Physical ; Theoretical Chemistry

  9. Structural features of lignohumic acids

    Novák, František; Šestauberová, Martina; Hrabal, R.

    2015-01-01

    Roč. 1093, August (2015), s. 179-185. ISSN 0022-2860 Institutional support: RVO:60077344 Keywords : C-13 NMR * FTIR * humic acids * lignohumate * lignosulfonate * structure Subject RIV: DF - Soil Science Impact factor: 1.602, year: 2014

  10. Acid Rain - Acidification and Recovery

    Norton, S. A.; Kopáček, Jiří; Fernandez, I. J.

    2. Elsevier, 2014 - (Holland., H.; Turekian, K.), s. 379-414 Institutional support: RVO:60077344 Keywords : acid ification * nitrogen * nutrients * sulfur * trace metals Subject RIV: DJ - Water Pollution ; Quality

  11. Uranium extraction from phosphoric acid

    A study has been carried out for the extraction of uranium from phosphoric acid produced in Algeria. First of all, the Algerian phosphoric acid produced in Algeria by SONATRACH has been characterised. This study helped us to synthesize a phosphoric acid that enabled us to pass from laboratory tests to pilot scale tests. We have then examined extraction and stripping parameters: diluent, DZEPHA/TOPO ratio and oxidising agent. The laboratory experiments enabled us to set the optimum condition for the choice of diluent, extractant concentration, ratio of the synergic mixture, oxidant concentration, redox potential. The equilibrium isotherms lead to the determination of the number of theoretical stages for the uranium extraction and stripping of uranium, then the extraction from phosphoric acid has been verified on a pilot scale (using a mixer-settler)

  12. Bile acid sequestrants for cholesterol

    ... ency/patientinstructions/000787.htm Bile acid sequestrants for cholesterol To use the sharing features on this page, ... are medicines that help lower your LDL (bad) cholesterol . Too much cholesterol in your blood can stick ...

  13. MedlinePlus: Folic Acid

    ... Tests Homocysteine Test (American Association for Clinical Chemistry) Vitamin B12 and Folate Test (American Association for Clinical Chemistry) Related Issues Folic Acid Supplements: Can They Slow Cognitive Decline? (Mayo Foundation for Medical Education and Research) Genetics ...

  14. Branched-Chain Amino Acids

    Pátek, Miroslav

    Berlin : Springer-Verlag Berlin Heidelberg, 2007, s. 129-162. ISBN 978-3-540-48595-7 Institutional research plan: CEZ:AV0Z50200510 Keywords : amino acids * homologous reactions Subject RIV: EE - Microbiology, Virology

  15. Acid diffusion through polymer films

    Zhang, P. Linda; Eckert, Andrew R.; Willson, C. Grant; Webber, Stephen E.; Byers, Jeffrey D.

    1997-07-01

    In order to perform 0.2 micrometer processes, one needs to study the diffusion of photoacid generators within the photoresist system, since diffusion during post exposure bake time has an influence on the critical dimension (CD). We have developed a new method to study the diffusion of photoacid generators within a polymer film. This new method is based on monitoring the change of the fluorescence intensity of a pH- sensitive fluorescent dye caused by the reaction with photoacid. A simplified version of this experiment has been conducted by introducing acid vapor to quench the fluorescence intensity of this pH sensor. A thin polymer film is spin cast onto the sensor to create a barrier to the acid diffusion process. During the acid diffusion process, the fluorescence intensity of this pH sensor is measured in situ, using excitation and emission wavelengths at 466 nm and 516 nm, respectively. Fluoresceinamine, the pH sensitive fluorescent dye, is covalently bonded onto the treated quartz substrate to form a single dye layer. Poly(hydroxystyrene) (Mn equals 13k, Tg equals 180 degrees Celsius) in PGMEA (5% - 18% by weight) is spin cast onto this quartz substrate to form films with varying thickness. The soft bake time is 60 seconds at 90 degrees Celsius and a typical film has a thickness of 1.4 micrometers. Trifluoroacetic acid is introduced into a small chamber while the fluorescence from this quartz window is observed. Our study focuses on finding the diffusion constant of the vaporized acid (trifluoroacetic acid) in the poly(hydroxystyrene) polymer film. By applying the Fick's second law, (It - Io)/(I(infinity ) - Io) equals erfc [L/(Dt)1/2] is obtained. The change of fluorescence intensity with respect to the diffusion time is monitored. The above equation is used for the data analysis, where L represents the film thickness and t represents the average time for the acid to diffuse through the film. The diffusion constant is calculated to be at the order of 10

  16. Simultaneous analysis of small organic acids and humic acids using high performance size exclusion chromatography

    Qin, X.P.; Liu, F.; Wang, G.C.; Weng, L.P.

    2012-01-01

    An accurate and fast method for simultaneous determination of small organic acids and much larger humic acids was developed using high performance size exclusion chromatography. Two small organic acids, i.e. salicylic acid and 2,3-dihydroxybenzoic acid, and one purified humic acid material were used

  17. Nucleic Acid Aptamers Against Proteases

    Dupont, D M; Andersen, L M; Bøtkjær, Kenneth Alrø;

    2011-01-01

    Proteases are potential or realized therapeutic targets in a wide variety of pathological conditions. Moreover, proteases are classical subjects for studies of enzymatic and regulatory mechanisms. We here review the literature on nucleic acid aptamers selected with proteases as targets. Designing...... strategies and of new principles for regulating the activity of the inhibitory action of aptamers of general interest to researchers working with nucleic acid aptamers...

  18. Piperidine nucleoside phosphonic acid derivatives

    Kovačková, Soňa; Dračínský, Martin; Rejman, Dominik

    Praha : Institute of Organic Chemistry and Biochemistry AS CR, v. v. i., 2011 - (Hocek, M.), s. 372-374 ISBN 978-80-86241-37-1. - (Collection Symposium Series. 12). [Chemistry of Nucleic Acid Components /15./. Český Krumlov (CZ), 05.06.2011-10.06.2011] Institutional research plan: CEZ:AV0Z40550506 Keywords : piperidine nucleoside * nucleoside phosphonic acids * nucleoside diphosphate analogs * nucleotide analogs Subject RIV: CC - Organic Chemistry

  19. Aqueous Photochemistry of Glyoxylic Acid.

    Eugene, Alexis J; Xia, Sha-Sha; Guzman, Marcelo I

    2016-06-01

    Aerosols affect climate change, the energy balance of the atmosphere, and public health due to their variable chemical composition, size, and shape. While the formation of secondary organic aerosols (SOA) from gas phase precursors is relatively well understood, studying aqueous chemical reactions contributing to the total SOA budget is the current focus of major attention. Field measurements have revealed that mono-, di-, and oxo-carboxylic acids are abundant species present in SOA and atmospheric waters. This work explores the fate of one of these 2-oxocarboxylic acids, glyoxylic acid, which can photogenerate reactive species under solar irradiation. Additionally, the dark thermal aging of photoproducts is studied by UV-visible and fluorescence spectroscopies to reveal that the optical properties are altered by the glyoxal produced. The optical properties display periodicity in the time domain of the UV-visible spectrum of chromophores with absorption enhancement (thermochromism) or loss (photobleaching) during nighttime and daytime cycles, respectively. During irradiation, excited state glyoxylic acid can undergo α-cleavage or participate in hydrogen abstractions. The use of (13)C nuclear magnetic resonance spectroscopy (NMR) analysis shows that glyoxal is an important intermediate produced during direct photolysis. Glyoxal quickly reaches a quasi-steady state as confirmed by UHPLC-MS analysis of its corresponding (E) and (Z) 2,4-dinitrophenylhydrazones. The homolytic cleavage of glyoxylic acid is proposed as a fundamental step for the production of glyoxal. Both carbon oxides, CO2(g) and CO(g) evolving to the gas-phase, are quantified by FTIR spectroscopy. Finally, formic acid, oxalic acid, and tartaric acid photoproducts are identified by ion chromatography (IC) with conductivity and electrospray (ESI) mass spectrometry (MS) detection and (1)H NMR spectroscopy. A reaction mechanism is proposed based on all experimental observations. PMID:27192089

  20. Deoxyribonucleic acid methylation in mycobacteria.

    R. Srivastava; Gopinathan, K P; Ramakrishnan, T.

    1981-01-01

    Deoxyribonucleic acid modification in six strains of mycobacteria was investigated. The presence of 5-methylcytosine in the virulent strain Mycobacterium tuberculosis H37Rv and its absence in the avirulent strain M. tuberculosis H37Ra and other saprophytic, fast-growing mycobacteria appear to be the salient features. However, deoxyribonucleic acid from M. smegmatis SN2 lysogenized with the temperature phage I3 showed the presence of 5-methylcytosine. All of the strains had N6-methyladenine.