Weak doping dependence of the antiferromagnetic coupling between nearest-neighbor Mn2 + spins in (Ba1 -xKx) (Zn1-yMny) 2As2

Science.gov (United States)

Surmach, M. A.; Chen, B. J.; Deng, Z.; Jin, C. Q.; Glasbrenner, J. K.; Mazin, I. I.; Ivanov, A.; Inosov, D. S.

2018-03-01

Dilute magnetic semiconductors (DMS) are nonmagnetic semiconductors doped with magnetic transition metals. The recently discovered DMS material (Ba1 -xKx) (Zn1-yMny) 2As2 offers a unique and versatile control of the Curie temperature TC by decoupling the spin (Mn2 +, S =5 /2 ) and charge (K+) doping in different crystallographic layers. In an attempt to describe from first-principles calculations the role of hole doping in stabilizing ferromagnetic order, it was recently suggested that the antiferromagnetic exchange coupling J between the nearest-neighbor Mn ions would experience a nearly twofold suppression upon doping 20% of holes by potassium substitution. At the same time, further-neighbor interactions become increasingly ferromagnetic upon doping, leading to a rapid increase of TC. Using inelastic neutron scattering, we have observed a localized magnetic excitation at about 13 meV associated with the destruction of the nearest-neighbor Mn-Mn singlet ground state. Hole doping results in a notable broadening of this peak, evidencing significant particle-hole damping, but with only a minor change in the peak position. We argue that this unexpected result can be explained by a combined effect of superexchange and double-exchange interactions.

Detector Mount Design for IGRINS

Directory of Open Access Journals (Sweden)

Jae Sok Oh

2014-06-01

Full Text Available The Immersion Grating Infrared Spectrometer (IGRINS is a near-infrared wide-band high-resolution spectrograph jointly developed by the Korea Astronomy and Space Science Institute and the University of Texas at Austin. IGRINS employs three HAWAII-2RG Focal Plane Array (H2RG FPA detectors. We present the design and fabrication of the detector mount for the H2RG detector. The detector mount consists of a detector housing, an ASIC housing, a Field Flattener Lens (FFL mount, and a support base frame. The detector and the ASIC housing should be kept at 65 K and the support base frame at 130 K. Therefore they are thermally isolated by the support made of GFRP material. The detector mount is designed so that it has features of fine adjusting the position of the detector surface in the optical axis and of fine adjusting yaw and pitch angles in order to utilize as an optical system alignment compensator. We optimized the structural stability and thermal characteristics of the mount design using computer-aided 3D modeling and finite element analysis. Based on the structural and thermal analysis, the designed detector mount meets an optical stability tolerance and system thermal requirements. Actual detector mount fabricated based on the design has been installed into the IGRINS cryostat and successfully passed a vacuum test and a cold test.

The T2K fine-grained detectors

Energy Technology Data Exchange (ETDEWEB)

Amaudruz, P.-A. [TRIUMF, Vancouver, British Columbia (Canada); Barbi, M. [University of Regina, Physics Department, Regina, Saskatchewan (Canada); Bishop, D. [TRIUMF, Vancouver, British Columbia (Canada); Braam, N. [University of Victoria, Department of Physics and Astronomy, Victoria, British Columbia (Canada); Brook-Roberge, D.G. [University of British Columbia, Department of Physics and Astronomy, Vancouver, British Columbia (Canada); Giffin, S. [University of Regina, Physics Department, Regina, Saskatchewan (Canada); Gomi, S. [Kyoto University, Department of Physics, Kyoto (Japan); Gumplinger, P.; Hamano, K. [TRIUMF, Vancouver, British Columbia (Canada); Hastings, N.C. [University of Regina, Physics Department, Regina, Saskatchewan (Canada); Hastings, S. [University of British Columbia, Department of Physics and Astronomy, Vancouver, British Columbia (Canada); Helmer, R.L., E-mail: helmer@triumf.ca [TRIUMF, Vancouver, British Columbia (Canada); Henderson, R. [TRIUMF, Vancouver, British Columbia (Canada); Ieki, K. [Kyoto University, Department of Physics, Kyoto (Japan); Jamieson, B. [University of British Columbia, Department of Physics and Astronomy, Vancouver, British Columbia (Canada); Kato, I.; Khan, N. [TRIUMF, Vancouver, British Columbia (Canada); Kim, J.; Kirby, B. [University of British Columbia, Department of Physics and Astronomy, Vancouver, British Columbia (Canada); Kitching, P. [University of Alberta, Centre for Particle Physics, Department of Physics, Edmonton, Alberta (Canada); and others

2012-12-22

T2K is a long-baseline neutrino oscillation experiment searching for {nu}{sub e} appearance in a {nu}{sub {mu}} beam. The beam is produced at the J-PARC accelerator complex in Tokai, Japan, and the neutrinos are detected by the Super-Kamiokande detector located 295 km away in Kamioka. A suite of near detectors (ND280) located 280 m downstream of the production target is used to characterize the components of the beam before they have had a chance to oscillate and to better understand various neutrino interactions on several nuclei. This paper describes the design and construction of two massive fine-grained detectors (FGDs) that serve as active targets in the ND280 tracker. One FGD is composed solely of scintillator bars while the other is partly scintillator and partly water. Each element of the FGDs is described, including the wavelength shifting fiber and Multi-Pixel Photon Counter used to collect the light signals, the readout electronics, and the calibration system. Initial tests and in situ results of the FGDs' performance are also presented.

Microstructures and Dehydrogenation Properties of Ball-milled MgH2-K2Ti6O13-Ni Composite Systems

Directory of Open Access Journals (Sweden)

ZHANG Jian

2016-11-01

Full Text Available The K2Ti6O13 whisker separate-doped and K2Ti6O13 whisker and Ni powder multi-doped MgH2 hydrogen storage composite systems were prepared by mechanical milling method. The microstructures and dehydrogenation properties of the prepared samples were characterized by some testing methods such as X-ray diffraction (XRD, scanning electron microscope (SEM and differential scanning calorimeter (DSC. The results show that the K2Ti6O13 whisker not only plays the roles in refining the MgH2 crystalline grain, but also inhibit the agglomeration of MgH2 particles in K2Ti6O13 whisker separate-doped system, which results in the decreased dehydrogenation temperature of MgH2 matrix. When the mass ratio of K2Ti6O13 to MgH2 is 3:7, the improvement effect on dehydrogenation properties of MgH2 is the most remarkable. As compared with pure ball-milled MgH2, the dehydrogenation temperature of MgH2 in K2Ti6O13 whisker separate-doped system is decreased by nearly 75℃. For K2Ti6O13 whisker and Ni powder multi-dopedsystem, the dehydrogenation temperature of MgH2 matrix is further decreased compared to K2Ti6O13 whisker separate-doped one due to the dual effects of refined MgH2 crystalline grain by K2Ti6O13 whisker and destabilized MgH2 lattice by Ni solution. As compared with pure ball-milled MgH2, the dehydrogenation temperature of MgH2 in K2Ti6O13 whisker and Ni powder multi-doped system is decreased by nearly 87℃.

The combinatorial PP1-binding consensus Motif (R/Kx( (0,1V/IxFxx(R/Kx(R/K is a new apoptotic signature.

Directory of Open Access Journals (Sweden)

Angélique N Godet

Full Text Available BACKGROUND: Previous studies established that PP1 is a target for Bcl-2 proteins and an important regulator of apoptosis. The two distinct functional PP1 consensus docking motifs, R/Kx((0,1V/IxF and FxxR/KxR/K, involved in PP1 binding and cell death were previously characterized in the BH1 and BH3 domains of some Bcl-2 proteins. PRINCIPAL FINDINGS: In this study, we demonstrate that DPT-AIF(1, a peptide containing the AIF(562-571 sequence located in a c-terminal domain of AIF, is a new PP1 interacting and cell penetrating molecule. We also showed that DPT-AIF(1 provoked apoptosis in several human cell lines. Furthermore, DPT-APAF(1 a bi-partite cell penetrating peptide containing APAF-1(122-131, a non penetrating sequence from APAF-1 protein, linked to our previously described DPT-sh1 peptide shuttle, is also a PP1-interacting death molecule. Both AIF(562-571 and APAF-1(122-131 sequences contain a common R/Kx((0,1V/IxFxxR/KxR/K motif, shared by several proteins involved in control of cell survival pathways. This motif combines the two distinct PP1c consensus docking motifs initially identified in some Bcl-2 proteins. Interestingly DPT-AIF(2 and DPT-APAF(2 that carry a F to A mutation within this combinatorial motif, no longer exhibited any PP1c binding or apoptotic effects. Moreover the F to A mutation in DPT-AIF(2 also suppressed cell penetration. CONCLUSION: These results indicate that the combinatorial PP1c docking motif R/Kx((0,1V/IxFxxR/KxR/K, deduced from AIF(562-571 and APAF-1(122-131 sequences, is a new PP1c-dependent Apoptotic Signature. This motif is also a new tool for drug design that could be used to characterize potential anti-tumour molecules.

Superconducting to spin-glass state transformation in β-pyrochlore KxOs2O6

Science.gov (United States)

Lee, C. C.; Lee, W. L.; Lin, J.-Y.; Tsuei, C. C.; Lin, J. G.; Chou, F. C.

2011-03-01

β-pyrochore KOs2O6, which shows superconductivity below ~9.7 K, has been converted into KxOs2O6 (x≲(2)/(3)-(1)/(2)) electrochemically to show spin-glass-like behavior below ~6.1 K. A room-temperature sample surface potential versus charge transfer scan indicates that there are at least two two-phase regions for x between 1 and 0.5. A rattling model of superconductivity for the title compound has been examined using electrochemical potassium de-intercalation. The significant reduction of superconducting volume fraction due to minor potassium reduction suggests the importance of defect and phase coherence in the rattling model. Magnetic susceptibility, resistivity, and specific heat measurement results have been compared between the superconducting and spin-glass-like samples.

Interpretation of chest radiographs with a high-resolution (2,000 x 2,000 x 12 bit) display

International Nuclear Information System (INIS)

Cox, G.G.

1989-01-01

This paper presents an evaluation of high-resolution (2K x 2Kx 12 bit) display for interpretation of chest radiographs. Three radiologists chose a total of 165 chest radiographs to ensure representation of nine signs: apical pleural scarring, chronic obstructive pulmonary disease, interstitial processes, atelectasis, pneumothorax, hilar mass, pleural effusion, pneumonia, and nodules. Each chest film was digitized to 4Kx 4Kx 12 bit and averaged to 2Kx 2Kx 12 bit and printed on a laser film printer. The 2K x 2K x 12-bit images were displayed and interactively windowed on a 2K x 2K x 12-bit high-resolution gray-scale cathode ray tube display. Six radiologists, none of whom participated in the case selection process, then interpreted a mixture of the screen film chest radiographs, the laser printed 2K chest radiographs, and the high resolution displayed 2K images

Identification of KX2-391 as an inhibitor of HBV transcription by a recombinant HBV-based screening assay.

Science.gov (United States)

Harada, Keisuke; Nishitsuji, Hironori; Ujino, Saneyuki; Shimotohno, Kunitada

2017-08-01

Antiviral therapies for chronic hepatitis B virus (HBV) infection that are currently applicable for clinical use are limited to nucleos(t)ide analogs targeting HBV polymerase activity and pegylated interferon alpha (PEG-IFN). Towards establishing an effective therapy for HBV related diseases, it is important to develop a new anti-HBV agent that suppresses and eradicates HBV. This study used recombinant HBV encoding NanoLuc to screen anti-HBV compounds from 1827 US Food and Drug Administration approved compounds and identified several compounds that suppressed HBV infection. Among them, KX2-391, a non-ATP-competitive inhibitor of SRC kinase and tubulin polymerization, was identified as a lead candidate for an anti-HBV drug. Treatment of sodium taurocholate cotransporting polypeptide (NTCP) transduced-HepG2 (HepG2-NTCP) or primary human hepatocytes with KX2-391 suppressed HBV replication in a dose-dependent manner. The anti-HBV activity of KX2-391 appeared not to depend on SRC kinase activity because siRNA for SRC mRNA did not impair the HBV infection/replication. The anti-HBV activity of KX2-391 depended on the inhibitory effect of tubulin polymerization similar to other tubulin polymerization inhibitors, some of which were shown to inhibit HBV replication. KX2-391 inhibited HBV transcription driven by a HBV precore promoter in an HBV X protein-independent manner but did not inhibit the activity of HBV-S1, -S2, -X or cytomegalovirus promoters. Treatment with KX2-391 reduced the expression of several various factors including hepatocyte nuclear factor-4a. Copyright © 2017 Elsevier B.V. All rights reserved.

Magnetic feature and near-infrared absorption of a [Pt(mnt)2]-based H-bond supramolecular crystal

International Nuclear Information System (INIS)

Li, Cui-Ping; Nie, Li; Pei, Wen-Bo; Li, Li; Tian, Zheng-Fang; Liu, Jian-Lan; Gao, Xu-Sheng; Ren, Xiao-Ming

2016-01-01

A new salt [H 2 DABCO][Pt(mnt) 2 ] 2 (1) (mnt 2- =maleonitriledithiolate and H 2 DABCO 2+ is diprotonated 1,4-diazabicyclo[2.2.2]octane) has been synthesized; its crystal structure, magnetic and near-IR absorption properties have been investigated. Two different [Pt(mnt) 2 ] - anions form the strong π-dimers, labeled as Pt(1)-dimer and Pt(2)-dimer, with quite shorter Pt…Pt and S…S distances and molecular plane-to-plane distance (<3.5 Å) within a dimer. The [Pt(mnt) 2 ] 2 2- π-dimers are connected through the cations in the strong H-bond manner to form three-dimensional H-bond supramolecular crystal. The salt shows weak paramagnetism in 1.99–300 K and this is due to the existence of strong antiferromagnetic coupling within a π-dimer. In addition, a small thermal hysteresis loop is observed at ca. 120 K, indicating that a phase transition probably occurs that is further confirmed by variable-temperature IR spectra. Another fascinating functionality of 1 is the intense near-IR absorption in the region of 750–2500 nm, and this near-IR absorption feature makes it to be a promising optical material. - Graphical abstract: A H-bond supramolecular crystal of [H 2 DABCO][Pt(mnt) 2 ] 2 shows a magnetic phase transition at ca. 120 K with sizable thermal hysteresis loop and intense near-IR absorption in the region of 750–2500 nm.

Colossal thermoelectric power factor in K7/8RhO2

KAUST Repository

Saeed, Yasir

2012-04-12

The thermoelectric properties of the layered oxides KxRhO 2 (x = 1/2 and 7/8) are investigated by means of the electronic structure, as determined by ab inito calculations and Boltzmann transport theory. In general, the electronic structure of K xRhO 2 is similar to Na xCoO 2, but with strongly enhanced transport. K 7/8RhO 2 exceeds the ultrahigh power factor of Na 0.88CoO 2 reported previously by more than 50%. The roles of the cation concentration and the lattice parameters in the transport properties in this class of compounds are explained. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Measurement of the Water to Scintillator Charged-Current Cross-Section Ratio for Muon Neutrinos at the T2K Near Detector

CERN Document Server

AUTHOR|(CDS)2083872

2017-10-02

The T2K experiment is a 295-km long-baseline neutrino experiment which aims at the measurement of neutrino oscillation parameters. Precise measurements of these parameters require accurate extrapolation of interaction rates from the near detector, ND280, mainly made of scintillator (hydrocarbon), to Super-Kamiokande, the water Cherenkov far detector. Measurements on water and of the water to hydrocarbon ratio, contribute to eliminate the uncertainties arising from carbon/oxygen differences. The cross section on water is obtained by subtraction of event distributions in two almost identical sub-detectors, one of which is equipped with water-filled modules. The measurement is performed by selecting a muon neutrino charged-current sample, in an exposure of 5.80 × 10^(20) protons on target. The water to hydrocarbon cross-section ratio is extracted for good acceptance kinematic regions (only forward muons with momentum higher than 100 MeV), in bins of reconstructed energy, the very quantity used in T2K oscillatio...

Relating 2-Rainbow Domination To Roman Domination

Directory of Open Access Journals (Sweden)

Alvarado José D.

2017-11-01

Full Text Available For a graph G, let R(G and yr2(G denote the Roman domination number of G and the 2-rainbow domination number of G, respectively. It is known that yr2(G ≤ R(G ≤ 3/2yr2(G. Fujita and Furuya [Difference between 2-rainbow domination and Roman domination in graphs, Discrete Appl. Math. 161 (2013 806-812] present some kind of characterization of the graphs G for which R(G − yr2(G = k for some integer k. Unfortunately, their result does not lead to an algorithm that allows to recognize these graphs efficiently. We show that for every fixed non-negative integer k, the recognition of the connected K4-free graphs G with yR(G − yr2(G = k is NP-hard, which implies that there is most likely no good characterization of these graphs. We characterize the graphs G such that yr2(H = yR(H for every induced subgraph H of G, and collect several properties of the graphs G with R(G = 3/2yr2(G.

Ab Initio Description of Disordered Sr1−xKxFe2As2 Using the Coherent Potential Approximation

KAUST Repository

Pulikkotil, J. J.

2010-04-29

The electronic structure of disordered Sr1−xKxFe2As2 is studied by ab initio density functional theory. As no superstructure and/or atomic short range ordering is reported for Sr1−xKxFe2As2, the coherent potential approximation can be used to describe the effects of chemical disorder. We find clear deviations from the rigid band model characteristics. Nonmagnetic calculations show an enhancement of the density of states at the Fermi energy in the range 0.4≤x≤0.65, which coincides with the region where experiments observe an enhanced superconducting transition temperature, and antiferromagnetic calculations indicate a significant renormalization of states at Fermi energy. Analyzing the distribution of the Fe 3d states over the range 0≤x≤1 we propose an effective three band model.

[Excitation transfer between high-lying states in K2 in collisions with ground state K and H2 molecules].

Science.gov (United States)

Shen, Xiao-Yan; Liu, Jing; Dai, Kang; Shen, Yi-Fan

2010-02-01

Pure potassium vapor or K-H2 mixture was irradiated in a glass fluorescence cell with pulses of 710 nm radiation from an OPO laser, populating K2 (1lambda(g)) state by two-photon absorption. Cross sections for 1lambda(g)-3lambda(g) transfer in K2 were determined using methods of molecular fluorescence. During the experiments with pure K vapor, the cell temperature was varied between 553 and 603 K. The K number density was determined spectroscopically by the white-light absorption measurement in the blue wing of the self-broadened resonance D2 line. The resulting fluorescence included a direct component emitted in the decay of the optically excitation and a sensitized component arising from the collisionally populated state. The decay signal of time-resolved fluorescence from1lambda(g) -->1 1sigma(u)+ transition was monitored. It was seen that just after the laser pulse the fluorescence of the photoexcited level decreased exponentially. The effective lifetimes of the 1lambda(g) state can be resolved. The plot of reciprocal of effective lifetimes of the 1lambda(g) state against K densities yielded the slope that indicated the total cross section for deactivation and the intercept that provided the radiative lifetime of the state. The radiative lifetime (20 +/- 2) ns was obtained. The cross section for deactivation of the K2(1lambda(g)) molecules by collisions with K is (2.5 +/- 0.3) x 10(-14) cm2. The time-resolved intensities of the K23lambda(g) --> 1 3sigma(u)+ (484 nm) line were measured. The radiative lifetime (16.0 +/- 3.2) ns and the total cross section (2.5 +/- 0.6) x 10(-14) cm2 for deactivation of the K2 (3lambda(g)) state can also be determined through the analogous procedure. The time-integrated intensities of 1lambda(g) --> 1 1sigma(u)+ and 3lambda(g) --> 1 3sigma(u)+ transitions were measured. The cross section (1.1 +/- 0.3) x10(-14) cm2 was obtained for K2 (1lambda(g))+ K --> K2 (3lambda(g)) + K collisions. During the experiments with K-H2 mixture, the

T2K neutrino flux prediction

CERN Document Server

Abe, K.

2013-01-02

The Tokai-to-Kamioka (T2K) experiment studies neutrino oscillations using an off-axis muon neutrino beam with a peak energy of about 0.6 GeV that originates at the J-PARC accelerator facility. Interactions of the neutrinos are observed at near detectors placed at 280 m from the production target and at the far detector -- Super-Kamiokande (SK) -- located 295 km away. The flux prediction is an essential part of the successful prediction of neutrino interaction rates at the T2K detectors and is an important input to T2K neutrino oscillation and cross section measurements. A FLUKA and GEANT3 based simulation models the physical processes involved in the neutrino production, from the interaction of primary beam protons in the T2K target, to the decay of hadrons and muons that produce neutrinos. The simulation uses proton beam monitor measurements as inputs. The modeling of hadronic interactions is re-weighted using thin target hadron production data, including recent charged pion and kaon measurements from the NA...

Synthesis and properties of electrically conductive, ductile, extremely long (~50 μm) nanosheets of K(x)CoO2·yH2O.

Science.gov (United States)

Aksit, Mahmut; Hoselton, Benjamin C; Kim, Ha Jun; Ha, Don-Hyung; Robinson, Richard D

2013-09-25

Extremely long, electrically conductive, ductile, free-standing nanosheets of water-stabilized KxCoO2·yH2O are synthesized using the sol-gel and electric-field induced kinetic-demixing (SGKD) process. Room temperature in-plane resistivity of the KxCoO2·yH2O nanosheets is less than ~4.7 mΩ·cm, which corresponds to one of the lowest resistivity values reported for metal oxide nanosheets. The synthesis produces tens of thousands of very high aspect ratio (50,000:50,000:1 = length/width/thickness), millimeter length nanosheets stacked into a macro-scale pellet. Free-standing nanosheets up to ~50 μm long are readily delaminated from the stacked nanosheets. High-resolution transmission electron microscopy (HR-TEM) studies of the free-standing nanosheets indicate that the delaminated pieces consist of individual nanosheet crystals that are turbostratically stacked. X-ray diffraction (XRD) studies confirm that the nanosheets are stacked in perfect registry along their c-axis. Scanning electron microscopy (SEM) based statistical analysis show that the average thickness of the nanosheets is ~13 nm. The nanosheets show ductility with a bending radius as small as ~5 nm.

Improvement programme of the UA2 detector

International Nuclear Information System (INIS)

Gaillard, J.M.

1985-01-01

The UA2 experiment took its first data in November 1981 and has been operating smoothly since then. After a long shut-down in 1986, the Sp anti pS collider will resume operation with a substantially higher luminosity than presently available. The recently approved Antiproton Collector should allow for a total integrated luminosity of nearly 10 pb -1 by the end of 1989. In order to make the best use of the increased luminosity in terms of physics results the performance of the present UA2 detector has to be simultaneously improved. In this report, discussions are made concerning calorimeter end caps, upgraded vertex detector, as well as end cap tracking and preshower. It is concluded that the new design results from a number of choices dictated by the following considerations: i) The upgraded UA2 must be operational in 1987, as soon as the Collider resumes operation, in order to maximise its physics output during the period when TEV 1, with nearly three times as high a c.m. energy, has not yet taken over leadership. ii) The upgraded UA2 must remain competitive on the major physics issues rather than diversify its detection capabilities. iii) Priority is given to the quality of the missing transverse energy measurement. iv) Modifications to the vertex detector aim at ensuring that multivertex events can be reconstructed and at improving the detector performance in relation with electron identification. (Nogami, K.)

PdMn and PdFe: New Materials for Temperature Measurement Near 2K

International Nuclear Information System (INIS)

Adriaans, M.J.; Aselage, T.L.; Day, P.K.; Duncan, R.V.; Klemme, B.J.; Sergatskov, D.A.

1999-01-01

Interest in the critical dynamics of superfluid 4 He in microgravity conditions has motivated the development of new high resolution thermometry technol- ogy for use in space experiments near 2K. The current material commonly used as the temperature sensing element for high resolution thermometers (HRTs) is copper ammonium bromide [Cu(NH 4 ) 2 Br 4 2H 2 0) or ''CAB'', which undergoes a ferromagnetic phase transition at 1.8K1. HRTs made from CAB have demonstrated low drift ( -13 K/s

Synthesis, structure, optical, photoluminescence and magnetic properties of K2[Co(C2O4)2(H2O)2]·4H2O

Science.gov (United States)

Narsimhulu, M.; Hussain, K. A.

2018-06-01

The synthesis, crystal structure, optical, photoluminescence and magnetic behaviour of potassium bis(oxalato)cobaltate(II)tertrahydrate{K2[Co(C2O4)2(H2O)2]·4H2O} are described. The compound was grown at room temperature from mixture of aqueous solutions by slow evaporation method. The X-ray crystallographic data showed that the compound belongs to the monoclinic crystal system with P21/n space group and Z = 4. The UV-visible diffuse absorbance spectra exhibited bands at 253, 285 and 541 nm in the visible and ultraviolet regions. The optical band gap of the compound was estimated as 3.4 eV. At room temperature, an intense photoluminescence was observed from this material around 392 nm when it excited at 254 nm. The variable temperature dc magnetic susceptibility measurements exposed paramagnetic behaviour at high temperatures and antiferromagnetic ordering at low temperatures.

Study of the solubility, viscosity and density in Na+, Zn2+/Cl− − H2O, Na+ − Zn2+ − (H2PO2)− − H2O, Na+, Cl−/(H2PO2)− − H2O, and Zn2+, Cl−/(H2PO2)− − H2O ternary systems, and in Na+, Zn2+/Cl−, (H2PO2)−//H2O reciprocal quaternary system at 273.15 K

International Nuclear Information System (INIS)

Adiguzel, Vedat; Erge, Hasan; Alisoglu, Vahit; Necefoglu, Hacali

2014-01-01

Highlights: • The physicochemical properties of ternary and one quaternary have been studied. • Reciprocal quaternary systems’ solubility and phase equilibrium have been studied. • In all systems the solid phases have been found. • It was found that Zn(H 2 PO 2 ) 2 salt contains 70% of the general crystallization field. - Abstract: The solubility and the physicochemical properties (density, viscosity) in the Na-Zn- Cl-H 2 O), (Na + Zn + H 2 PO 2 + H 2 O), (Na + Cl + H 2 PO 2 + H 2 O), and (Zn + Cl + H 2 PO 2 + H 2 O) ternaries, and in Na + , Zn 2+ /Cl − , (H 2 PO 2 ) − //H 2 O reciprocal quaternary systems at T = 273.15 K were investigated by using the isothermal method. The diagrams of ternary salts systems, (NaCl + ZnCl 2 + H 2 O), (NaCl + NaH 2 PO 2 + H 2 O), (NaH 2 PO 2 + Zn(H 2 PO 2 ) 2 + H 2 O), (ZnCl 2 + Zn(H 2 PO 2 ) 2 + H 2 O), are plotted in figures 1–4. However, whole ions of reciprocal quaternary salt systems are plotted in figure 5. Additionally, the density and viscosity values of ternary systems vs. their corresponding composition values in weight per cent are plotted in figures 6–10. At the (i) (ZnCl 2 + Zn(H 2 PO 2 ) 2 + H 2 O), (ii) (NaCl + ZnCl 2 + H 2 O), (iii) (NaCl + NaH 2 PO 2 + H 2 O), (iv) (NaH 2 PO 2 + Zn(H 2 PO 2 ) 2 + H 2 O) ternary systems the solid phase compositions have been determined as: (i) Zn(H 2 PO 2 ) 2 ⋅ H 2 O, Zn(H 2 PO 2 ) 2 , ZnCl 2 ⋅ 2H 2 O, (ii) NaCl, 2NaCl ⋅ ZnCl 2 ⋅ 2H 2 O, and ZnCl 2 ⋅ 2H 2 O, (iii) NaCl and NaH 2 PO 2 ⋅ H 2 O, (iv) Zn(H 2 PO 2 ) 2 ⋅ H 2 O and NaH 2 PO 2 ⋅ H 2 O, respectively. On the other hand reciprocal quaternary system was observed as: ZnCl 2 ⋅ 2H 2 O, 2NaCl ⋅ ZnCl 2 ⋅ 2H 2 O, Zn(H 2 PO 2 ) 2 ⋅ H 2 O, NaH 2 PO 2 ⋅ H 2 O, NaCl. According to results, the least soluble salt was Zn(H 2 PO 2 ) 2 . The crystallization field of this salt, being the largest in comparison with those of other salts, occupied 70% of the general crystallization field

H2A/K pseudogene mutation may promote cell proliferation

Energy Technology Data Exchange (ETDEWEB)

Guo, Jisheng; Jing, Ruirui; Lv, Xin; Wang, Xiaoyue; Li, Junqiang; Li, Lin; Li, Cuiling; Wang, Daoguang; Bi, Baibing; Chen, Xinjun [Cancer Research Center, Shandong University School of Medicine, Jinan 250012 (China); Yang, Jing-Hua, E-mail: sdu_crc_group1@126.com [Cancer Research Center, Shandong University School of Medicine, Jinan 250012 (China); Department of Surgery, VA Boston Healthcare System, Boston University School of Medicine, Boston 510660, MA (United States)

2016-05-15

Highlights: • The mutant H2A/K pseudogene is active. • The mutant H2A/K pseudogene can promote cell proliferation. - Abstract: Little attention has been paid to the histone H2A/K pseudogene. Results from our laboratory showed that 7 of 10 kidney cancer patients carried a mutant H2A/K pseudogene; therefore, we were interested in determining the relationship between mutant H2A/K and cell proliferation. We used shotgun and label-free proteomics methods to study whether mutant H2A/K lncRNAs affected cell proliferation. Quantitative proteomic analysis indicated that the expression of mutant H2A/K lncRNAs resulted in the upregulation of many oncogenes, which promoted cell proliferation. Further interaction analyses revealed that a proliferating cell nuclear antigen (PCNA)-protein interaction network, with PCNA in the center, contributes to cell proliferation in cells expressing the mutant H2A/K lncRNAs. Western blotting confirmed the critical upregulation of PCNA by mutant H2A/K lncRNA expression. Finally, the promotion of cell proliferation by mutant H2A/K lncRNAs (C290T, C228A and A45G) was confirmed using cell proliferation assays. Although we did not determine the exact mechanism by which the oncogenes were upregulated by the mutant H2A/K lncRNAs, we confirmed that the mutant H2A/K lncRNAs promoted cell proliferation by upregulating PCNA and other oncogenes. The hypothesis that cell proliferation is promoted by the mutant H2A/K lncRNAs was supported by the protein expression and cell proliferation assay results. Therefore, mutant H2A/K lncRNAs may be a new factor in renal carcinogenesis.

Enhanced hydrogen storage properties of MgH2 co-catalyzed with K2NiF6 and CNTs.

Science.gov (United States)

Sulaiman, N N; Ismail, M

2016-12-06

The composite of MgH 2 /K 2 NiF 6 /carbon nanotubes (CNTs) is prepared by ball milling, and its hydrogenation properties are studied for the first time. MgH 2 co-catalyzed with K 2 NiF 6 and CNTs exhibited an improvement in the onset dehydrogenation temperature and isothermal de/rehydrogenation kinetics compared with the MgH 2 -K 2 NiF 6 composite. The onset dehydrogenation temperature of MgH 2 doped with 10 wt% K 2 NiF 6 and 5 wt% CNTs is 245 °C, which demonstrated a reduction of 25 °C compared with the MgH 2 + 10 wt% K 2 NiF 6 composite. In terms of rehydrogenation kinetics, MgH 2 doped with 10 wt% K 2 NiF 6 and 5 wt% CNTs samples absorbed 3.4 wt% of hydrogen in 1 min at 320 °C, whereas the MgH 2 + 10 wt% K 2 NiF 6 sample absorbed 2.6 wt% of hydrogen under the same conditions. For dehydrogenation kinetics at 320 °C, the MgH 2 + 10 wt% K 2 NiF 6 + 5 wt% CNTs sample released 3.3 wt% hydrogen after 5 min of dehydrogenation. By contrast, MgH 2 doped with 10 wt% K 2 NiF 6 released 3.0 wt% hydrogen in the same time period. The apparent activation energy, E a , for the dehydrogenation of MgH 2 doped with 10 wt% K 2 NiF 6 reduced from 100.0 kJ mol -1 to 70.0 kJ mol -1 after MgH 2 was co-doped with 10 wt% K 2 NiF 6 and 5 wt% CNTs. Based on the experimental results, the hydrogen storage properties of the MgH 2 /K 2 NiF 6 /CNTs composite is enhanced because of the catalytic effects of the active species of KF, KH and Mg 2 Ni that are formed in situ during dehydrogenation, as well as the unique structure of CNTs.

Complexation in the system K2SeO4-UO2SeO4-H2O

International Nuclear Information System (INIS)

Serezhkina, L.B.; Kuchumova, N.V.; Serezhkin, V.N.

1994-01-01

Complexation in the system K 2 SeO 4 -UO 2 SeO 4 -H 2 O at 25 degrees C is studied by isothermal solubility. Congruently soluble K 2 UO 2 (SeO 4 ) 2 ·4H 2 O (I) and incongruently soluble K 2 (UO 2 ) 2 (SeO 4 ) 3 ·6H 2 O (II) are observed. The unit-cell constants of I and II are determined from an X-ray diffraction investigation. For I, a = 12,969, b = 11.588, c = 8.533 angstrom, Z = 4, space group Pmmb. For II, a = 23.36, b = 6.784, c = 13.699 angstrom, β = 104.42 degrees, Z = 4, space group P2/m, P2, or Pm. Complexes I and II are representatives of the crystal-chemical groups AB 2 2 M 1 and A 2 T 3 3 M 1 , respectively, of uranyl complexes

Systems Li2B4O7 (Na2B4O7, K2B4O7)-N2H3H4OH-H2O at 25 deg C

International Nuclear Information System (INIS)

Skvortsov, V.G.; Sadetdinov, Sh.V.; Akimov, V.M.; Mitrasov, Yu.N.; Petrova, O.V.; Klopov, Yu.N.

1994-01-01

Phase equilibriums in the Li 2 B 4 O 7 (Na 2 B 4 O 7 , K 2 B 4 O 7 )-N 2 H 3 H 4 OH-H 2 O systems were investigated by methods of isothermal solubility, refractometry and PH-metry at 25 deg C for the first time. Lithium and sodium tetraborates was established to form phases of changed composition mM 2 B 4 O 7 ·nN 2 H 3 C 2 H 4 OH·XH 2 O, where M=Li, Na with hydrazine ethanol. K 2 B 4 O 7 ·4H 2 O precipitates in solid phase in the case of potassium salt. Formation of isomorphous mixtures was supported by X-ray diffraction and IR spectroscopy methods

Life-finding detector development at NASA GSFC using a custom H4RG test bed

Science.gov (United States)

Mosby, Gregory; Rauscher, Bernard; Kutyrev, Alexander

2018-01-01

Chemical species associated with life, called biosignatures, should be visible in exoplanet atmospheres with larger space telescopes. These signals will be faint and require very low noise (~e-) detectors to robustly measure. At NASA Goddard we are developing a single detector H4RG test bed to characterize and identify potential technology developments needed for the next generation's large space telescopes. The vacuum and cryogenic test bed will include near infrared light sources from integrating spheres using a motorized shutter. The detector control and readout will be handled by a Leach controller. Detector cables have been manufactured and test planning has begun. Planned tests include testing minimum read noise capabilities, persistence mitigation strategies using long wavelength light, and measuring intrapixel variation which might affect science goals of future missions. In addition to providing a means to identify areas of improvement in detector technology, we hope to use this test bed to probe some fundamental physics of these infrared arrays.

Total scattering cross-sections for the systems nH2 + nH2, pH2 + pH2, nD2 + nD2, oD2 + oD2 and HD + HD for relative energies below ten milli-electron volts

International Nuclear Information System (INIS)

Johnson, D.L.

1979-01-01

Relative total scattering cross sections for nH 2 + nH 2 , pH 2 + pH 2 , nD 2 + nD 2 , oD 2 + oD 2 , and HD + HD were measured with inclined nozzle beams derived from nozzle sources and intersecting at 21 0 . Both nozzles could be varied in temperature from 4.2K to 300K to provide the velocity range for the cross sections. The use of a parahydrogen converter allowed the measurement of the pH 2 + pH 2 and oD 2 + oD 2 cross sections. Cross sections for the H 2 + H 2 were measured over a relative velocity range of 200 m/s to 1450 m/s. The nH 2 + nH 2 results show an undulation in the velocity range between 350 m/s and 400 m/s that corresponds to a l = 3 orbiting resonance. Analysis of the pH 2 + pH 2 cross section indicates a l = 4 orbiting resonance near 586 m/s. This resonance has a peak energy of 1.79 meV and a measured energy width of 1.05 meV, both which agree well with theoretical predictions. The D 2 + D 2 cross sections have been measured in the velocity range between 190 m/s and 1000 m/s. No orbiting resonances have been observed, but in the oD 2 + oD 2 cross section a deep minimum between the l = 4 and the l = 5 resonances at low velocities is clearly suggested. Initial measurements of the HD + HD cross section suggests the presence of the l = 4 orbiting resonance near a relative velocity of 300 m/s. The experimental results for each system were normalized to the total cross sections, which were convoluted to account for experimental velocity and angular dispersions. Three different potentials were considered, but a chi-square fit of the data indicates that the Schaefer and Meyer potential, which has been theoretically obtained from first principles, provides the best overall description of the hydrogen systems in the low collisional energy range

Photolysis of H2O-H2O2 Mixtures: The Destruction of H2O2

Science.gov (United States)

Loeffler, M. J.; Fama, M.; Baragiola, R. A.; Carlson, R. W.

2013-01-01

We present laboratory results on the loss of H2O2 in solid H2O + H2O2 mixtures at temperatures between 21 and 145 K initiated by UV photolysis (193 nm). Using infrared spectroscopy and microbalance gravimetry, we measured the decrease of the 3.5 micrometer infrared absorption band during UV irradiation and obtained a photodestruction cross section that varies with temperature, being lowest at 70 K. We use our results, along with our previously measured H2O2 production rates via ionizing radiation and ion energy fluxes from the spacecraft to compare H2O2 creation and destruction at icy satellites by ions from their planetary magnetosphere and from solar UV photons. We conclude that, in many cases, H2O2 is not observed on icy satellite surfaces because the H2O2 photodestruction rate is much higher than the production rate via energetic particles, effectively keeping the H2O2 infrared signature at or below the noise level.

Study of the expected performance of the T2K experiment on muon neutrino to electron neutrino oscillation using data from K2K experiment

International Nuclear Information System (INIS)

Fechner, M.

2006-05-01

T2K is a neutrino oscillation experiment that will use the intense 2.5 degrees off-axis ν μ beam produced at J-PARC (Japan). The far detector is Super-Kamiokande (SK), the 50 kt water Cherenkov detector located 295 km from J-PARC. The goal is to search for ν e appearance, which will bring new information on θ 13 . The main background for ν e appearance comes from intrinsic beam ν e events (∼ 55%), and from mis-identified neutral current π 0 events (∼ 45%); near detectors are needed to measure these background components before oscillation. A detector complex (2KM) including a water Cherenkov detector, located ∼ 1.8 km away from the source is under active study. This distance is advantageous because the neutrino spectrum is only a few percent different from that of SK, thereby reducing extrapolation systematics. In order to match SK performance, the water Cherenkov detector was designed with ∼ 5600 8-inch photo-multiplier tubes, after studies based on full simulation tuned to K2K data. The water Cherenkov reconstruction algorithms, mainly particle identification and e/π 0 separation, were also studied at 2KM. Studies of ν e appearance in the water Cherenkov detector show that using simple scaling extrapolation we conservatively predict 23.0 ± 8.0% (stat + syst) background events at SK for 5. 10 21 p.o.t., in excellent agreement with the 23.8 background events obtained from an independent simulation of SK. The 2KM detector can achieve background subtraction to better than 10% accuracy, sufficient for T2K phase I. Detailed sensitivity studies, including all the relevant sources of systematics, show that the 2KM detector improves the sensitivity to sin 2 (2θ 13 ) down to ∼ 1.4. 10 -2 at 90% CL. (author)

Morphine dependence is attenuated by red ginseng extract and ginsenosides Rh2, Rg3, and compound K

OpenAIRE

Yayeh, Taddesse; Yun, Kyunghwa; Jang, Soyong; Oh, Seikwan

2016-01-01

Background: Red ginseng and ginsenosides have shown plethoric effects against various ailments. However, little is known regarding the effect of red ginseng on morphine-induced dependence and tolerance. We therefore investigated the effect of red ginseng extract (RGE) and biotransformed ginsenosides Rh2, Rg3, and compound K on morphine-induced dependence in mice and rats. Methods: While mice were pretreated with RGE and then morphine was injected intraperitoneally, rats were infused with g...

Results from Super-Kamiokande and K2K

Indian Academy of Sciences (India)

The probability of flavor oscillation (in the simplest, two-component case) is ..... K2K had collected about half of its total planned protons-on-target when the accident at ... [14] Design, construction, and operation of SciFi tracking detector for K2K ...

New results from T2K

CERN Multimedia

CERN. Geneva

2013-01-01

The Tokai to Kamioka (T2K) experiment is a long baseline neutrino oscillation experiment situated in Japan. A high intensity neutrino beam is produced at the Japan Proton Accelerator Research Complex, in Tokai, Japan. In 2011, the collaboration announced the first indication of muon neutrino to electron neutrino transformation, which was then a new type of neutrino oscillation; now, with 3.5 times more data, this transformation is firmly established. This T2K observation is the first of its kind in that an explicit appearance of a unique flavor of neutrino at a detection point is unequivocally observed from a different flavor of neutrino at its production point. The T2K collaboration also reports a precision measurement of muon neutrino disappearance with an ooff-axis neutrino beam with a peak energy of 0.6 GeV. Near detector is used in both oscillation measurements to constrain the neutrino flux and cross section parameters.

Thermodynamic modeling of NH_3-CO_2-SO_2-K_2SO_4-H_2O system for combined CO_2 and SO_2 capture using aqueous NH_3

International Nuclear Information System (INIS)

Qi, Guojie; Wang, Shujuan

2017-01-01

Highlights: • A new application of aqueous NH_3 based combined CO_2 and SO_2 process was proposed. • A thermodynamic model simulated the heat of absorption and the K_2SO_4 precipitation. • The CO_2 content can be regenerated in a stripper with lower heat of desorption. • The SO_2 content can be removed by K_2SO_4 precipitation from the lean NH_3 solvent. - Abstract: A new application of aqueous NH_3 based post-combustion CO_2 and SO_2 combined capture process was proposed to simultaneously capture CO_2 and SO_2, and remove sulfite by solid (K_2SO_4) precipitation method. The thermodynamic model of the NH_3-CO_2-SO_2-K_2SO_4-H_2O system for the combined CO_2 and SO_2 capture process was developed and validated in this work to analyze the heat of CO_2 and SO_2 absorption in the NH_3-CO_2-SO_2-H_2O system, and the K_2SO_4 precipitation characteristics in the NH_3-CO_2-SO_2-K_2SO_4-H_2O system. The average heat of CO_2 absorption in the NH_3-CO_2-H_2O system at 40 °C is around −73 kJ/mol CO_2 in 2.5 wt% NH_3 with CO_2 loading between 0.2 and 0.5 C/N. The average heat of SO_2 absorption in the NH_3-SO_2-H_2O system at 40 °C is around −120 kJ/mol SO_2 in 2.5 wt% NH_3 with SO_2 loading between 0 and 0.5 S/N. The average heat of CO_2 absorption in the NH_3-CO_2-SO_2-H_2O system at 40 °C is 77, 68, and 58 kJ/mol CO_2 in 2.5 wt% NH_3 with CO_2 loading between 0.2 and 0.5 C/N, when SO_2 loading is 0, 0.1, 0.2 S/N, respectively. The solubility of K_2SO_4 increases with temperature, CO_2 and SO_2 loadings, but decreases with NH_3 concentration in the CO_2 and SO_2 loaded aqueous NH_3. The thermodynamic evaluation indicates that the combined CO_2 and SO_2 capture process could employ the typical absorption/regeneration process to simultaneously capture CO_2 and SO_2 in an absorber, thermally desorb CO_2 in a stripper, and feasibly remove sulfite (oxidized to sulfate) content by precipitating K_2SO_4 from the lean NH_3 solvent after the lean/rich heat exchanger.

X-ray irradiation activates K+ channels via H2O2 signaling.

Science.gov (United States)

Gibhardt, Christine S; Roth, Bastian; Schroeder, Indra; Fuck, Sebastian; Becker, Patrick; Jakob, Burkhard; Fournier, Claudia; Moroni, Anna; Thiel, Gerhard

2015-09-09

Ionizing radiation is a universal tool in tumor therapy but may also cause secondary cancers or cell invasiveness. These negative side effects could be causally related to the human-intermediate-conductance Ca2+-activated-K+-channel (hIK), which is activated by X-ray irradiation and affects cell proliferation and migration. To analyze the signaling cascade downstream of ionizing radiation we use genetically encoded reporters for H2O2 (HyPer) and for the dominant redox-buffer glutathione (Grx1-roGFP2) to monitor with high spatial and temporal resolution, radiation-triggered excursions of H2O2 in A549 and HEK293 cells. The data show that challenging cells with ≥1 Gy X-rays or with UV-A laser micro-irradiation causes a rapid rise of H2O2 in the nucleus and in the cytosol. This rise, which is determined by the rate of H2O2 production and glutathione-buffering, is sufficient for triggering a signaling cascade that involves an elevation of cytosolic Ca2+ and eventually an activation of hIK channels.

Magnetism of CuCl{sub 2}·2D{sub 2}O and CuCl{sub 2}·2H{sub 2}O, and of CuBr{sub 2}·6H{sub 2}O

Energy Technology Data Exchange (ETDEWEB)

DeFotis, G.C., E-mail: gxdefo@wm.edu [Department of Chemistry, College of William and Mary, Williamsburg, VA 23187 (United States); Hampton, A.S.; Van Dongen, M.J.; Komatsu, C.H.; Benday, N.S.; Davis, C.M. [Department of Chemistry, College of William and Mary, Williamsburg, VA 23187 (United States); Hays, K.; Wagner, M.J. [Department of Chemistry, George Washington University, Washington, D.C. 20052 (United States)

2017-07-15

Highlights: • CuCl{sub 2}·2D{sub 2}O is examined magnetically and compared with CuCl{sub 2}·2H{sub 2}O. • Slightly lower magnetic characteristic temperatures occur for deuterated dihydrate. • The new compound CuBr{sub 2}·6H{sub 2}O is examined magnetically. • Unexpected relationships appears between magnetic behaviors of CuBr{sub 2}·6H{sub 2}O and CuBr{sub 2}. • Two alternative monoclinic unit cells can account for diffraction data on CuBr{sub 2}·6H{sub 2}O. - Abstract: The magnetic properties of little examined CuCl{sub 2}·2D{sub 2}O are studied and compared with those of CuCl{sub 2}·2H{sub 2}O. New CuBr{sub 2}·6H{sub 2}O is also examined. Susceptibility maxima appear for chlorides at 5.35 and 5.50 K, in the above order, with estimated antiferromagnetic ordering at 4.15 and 4.25 K. Curie-Weiss fits yield g of 2.210 and 2.205, and Weiss θ of −6.0 and −4.7 K, respectively, in χ{sub M} = C/(T − θ). One-dimensional Heisenberg model fits to susceptibilities, including interchain exchange in a mean-field approximation, are performed. Interchain exchange is significant but much weaker than intrachain. The bromide hexahydrate strongly differs magnetically from any chloride hydrate, but exhibits notable similarities and differences compared to previously studied CuBr{sub 2}. A broad susceptibility maximum occurs near 218 K, only 4% lower than for CuBr{sub 2}, but with almost twice the magnitude. Powder X-ray diffraction data for CuBr{sub 2}·6H{sub 2}O may be best accounted for by a monoclinic unit cell that is metrically orthorhombic. The volume per formula unit is consistent with trends in metal ionic radii. However, an alternative monoclinic cell with 5% smaller volume more readily rationalizes the magnetism.

Pressure-induced phase transition in KxFe2-yS2

International Nuclear Information System (INIS)

Tsuchiya, Yuu; Ikeda, Shugo; Kobayashi, Hisao; Zhang, Xiao-Wei; Kishimoto, Shunji; Kikegawa, Takumi; Hirao, Naohisa; Kawaguchi, Saori I.; Ohishi, Yasuo

2017-01-01

The structural and electronic properties of high-quality K 0.66(6) Fe 1.75(10) S 2 single crystals have been investigated by angle-resolved X-ray diffraction and 57 Fe nuclear forward scattering using synchrotron radiation under pressure at room temperature. The samples exhibit phase separation into antiferromagnetic ordered K 2 Fe 4 S 5 and nonmagnetic K x Fe 2 S 2 phases. It was found that a pressure-induced phase transition occurs at p c = 5.9(4) GPa with simultaneous suppression of the antiferromagnetic and Fe vacancy orders. >From the results of 57 Fe nuclear forward scattering, the refined magnetic hyperfine field remains unchanged with pressure below p c , suggesting that the Néel temperature does not decrease with pressure up to p c . Above p c , all Fe atoms in K 0.66 Fe 1.75 S 2 are in the same nonmagnetic state. A discontinuous increase in the center shift was observed at p c , reflecting a change in the Fe electronic state in K 0.66 Fe 1.75 S 2 . (author)

Particle Identification in the T2K TPCs and study of the electron neutrino component in the T2K neutrino beam

International Nuclear Information System (INIS)

Giganti, Claudio

2010-01-01

This thesis describes the work done on the TPCs of the Near Detector of the T2K experiment. T2K is an experiment installed in Japan and its main purpose is the measurement of the last angle of the neutrino mixing matrix, Θ 13 . The other two angles of the matrix have already been measured in the last years, through the phenomenon of the neutrino oscillations, showing that the neutrinos have masses different from zero. The measurement of the missing angle Θ 13 is of fundamental importance for the neutrino physics as, if this angle is different from zero, CP violation in the lepton sector can occur. Up to now only upper limits on the value of Θ 13 exist: the aim of T2K is to measure this angle or to put upper limits on it with a sensitivity 20 times better than the current limit. This measurement will be done measuring the appearance at the far detector, SuperKamiokande, of electron neutrinos in the muon neutrino beam produced at JPARC. The main background to the measurement of Θ 13 is the electron neutrinos produced together with the muon neutrinos in the beam: this component, expected to be of the order of 1% of the total neutrino flux, has to be measured at the T2K Near Detector, before the oscillations. This can be done selecting neutrino interactions in the Near Detector tracker and using the TPC particle identification capabilities to distinguish electrons from muons. This allows to select a sample of electron neutrino interactions and to measure their spectrum at the Near Detector. During this thesis I have developed the methods to perform the particle identification in the TPCs: the method is based on the measurement of the truncated mean of the energy deposited by the charged particles in the gas: at the typical energy of the T2K neutrinos the difference in the deposited energy between muons and electrons is of the order of 40% and for this reason a resolution better than 10% is needed to distinguish the two particles: as we will show in the thesis, with

Performance overview of the Euclid infrared focal plane detector subsystems

Science.gov (United States)

Waczynski, A.; Barbier, R.; Cagiano, S.; Chen, J.; Cheung, S.; Cho, H.; Cillis, A.; Clémens, J.-C.; Dawson, O.; Delo, G.; Farris, M.; Feizi, A.; Foltz, R.; Hickey, M.; Holmes, W.; Hwang, T.; Israelsson, U.; Jhabvala, M.; Kahle, D.; Kan, Em.; Kan, Er.; Loose, M.; Lotkin, G.; Miko, L.; Nguyen, L.; Piquette, E.; Powers, T.; Pravdo, S.; Runkle, A.; Seiffert, M.; Strada, P.; Tucker, C.; Turck, K.; Wang, F.; Weber, C.; Williams, J.

2016-07-01

In support of the European space agency (ESA) Euclid mission, NASA is responsible for the evaluation of the H2RG mercury cadmium telluride (MCT) detectors and electronics assemblies fabricated by Teledyne imaging systems. The detector evaluation is performed in the detector characterization laboratory (DCL) at the NASA Goddard space flight center (GSFC) in close collaboration with engineers and scientists from the jet propulsion laboratory (JPL) and the Euclid project. The Euclid near infrared spectrometer and imaging photometer (NISP) will perform large area optical and spectroscopic sky surveys in the 0.9-2.02 μm infrared (IR) region. The NISP instrument will contain sixteen detector arrays each coupled to a Teledyne SIDECAR application specific integrated circuit (ASIC). The focal plane will operate at 100K and the SIDECAR ASIC will be in close proximity operating at a slightly higher temperature of 137K. This paper will describe the test configuration, performance tests and results of the latest engineering run, also known as pilot run 3 (PR3), consisting of four H2RG detectors operating simultaneously. Performance data will be presented on; noise, spectral quantum efficiency, dark current, persistence, pixel yield, pixel to pixel uniformity, linearity, inter pixel crosstalk, full well and dynamic range, power dissipation, thermal response and unit cell input sensitivity.

The PB2-K627E mutation attenuates H3N2 swine influenza virus in cultured cells and in mice.

Science.gov (United States)

Gong, Xiao-Qian; Ruan, Bao-Yang; Liu, Xiao-Min; Zhang, Peng; Wang, Xiu-Hui; Wang, Qi; Shan, Tong-Ling; Tong, Wu; Zhou, Yan-Jun; Li, Guo-Xin; Zheng, Hao; Tong, Guang-Zhi; Yu, Hai

2018-04-01

PB2-627K is an important amino acid that determines the virulence of some influenza A viruses. However, it has not been experimentally investigated in the H3N2 swine influenza virus. To explore the potential role of PB2-K627E substitution in H3N2 swine influenza virus, the growth properties and pathogenicity between H3N2 swine influenza virus and its PB2-K627E mutant were compared. For the first time, our results showed that PB2-K627E mutation attenuates H3N2 swine influenza virus in mammalian cells and in mice, suggesting that PB2-627K is required for viral replication and pathogenicity of H3N2 swine influenza virus. Copyright © 2017 Elsevier Ltd. All rights reserved.

Surface reactions during low-k etching using H2/N2 plasma

International Nuclear Information System (INIS)

Fukasawa, Masanaga; Tatsumi, Tetsuya; Oshima, Keiji; Nagahata, Kazunori; Uchida, Saburo; Takashima, Seigo; Hori, Masaru; Kamide, Yukihiro

2008-01-01

We investigated the relationship between the hard mask faceting that occurs during organic low-k etching and the ion energy distribution function of a capacitively coupled plasma reactor. We minimized the hard mask faceting by precisely controlling the ion energy. This precise control was obtained by selecting the optimum bottom frequency and bias power. We measured the amount of damage done to a SiOCH film exposed to H 2 /N 2 plasma in order to find the H 2 /N 2 ratio at which the plasma caused the least damage. The amount of moisture uptake by the damaged SiOCH film is the dominant factor controlling the dielectric constant increase (Δk). To suppress Δk, the incident ion species and ion energies have to be precisely controlled. This reduces the number of adsorption sites in the bulk SiOCH and maintains the hydrophobic surface that suppresses water permeation during air exposure

First Measurement of the Muon Neutrino Charged Current Single Pion Production Cross Section on Water with the T2K Near Detector

CERN Document Server

Abe, K.

2017-01-26

The T2K off-axis near detector, ND280, is used to make the first differential cross section measurements of muon neutrino charged current single positive pion production on a water target at energies ${\\sim}0.8$~GeV. The differential measurements are presented as a function of muon and pion kinematics, in the restricted phase-space defined by $p_{\\pi^+}>200$MeV/c, $p_{\\mu^-}>200$MeV/c, $\\cos \\theta_{\\pi^+}>0.3$ and $\\cos \\theta_{\\mu^-}>0.3$. The total flux integrated $\

Indication of Electron Neutrino Appearance in the T2K experiment and its long-term implications

CERN Multimedia

CERN. Geneva

2011-01-01

T2K (Tokai-to-Kamioka) is a long-baseline neutrino oscillation experiment primarily searching for oscillations of muon neutrinos into electron neutrinos. T2K will also make precise measurements of the atmospheric oscillation parameters via muon neutrino disappearance. The experiment uses 30 GeV protons from the new J-PARC Main Ring accelerator, located in Tokai, Japan, to generate a conventional neutrino beam to the Super-Kamiokande far detector. The hadron production measurements of the NA61 experiment at CERN were used to predict the neutrino fluxes at the near and far detectors. The T2K oscillation analysis compares the rates of observed and predicted muon and electron neutrino candidates in the far detector. We present first results based on data accumulated from January 2010 to March 2011. Six electron neutrino events pass the selection criteria for electron appearance at Super-Kamiokande, whereas the expected number of background events is 1.5±0.3. The probability of a fluctuation of the back...

Structure of ferroelastic K3H(SeO4)2

International Nuclear Information System (INIS)

Ichikawa, M.; Sato, S.; Komukae, M.; Osaka, T.

1992-01-01

Tripotassium hydrogenbis(selenate), K 3 H(SeO 4 ) 2 , M r = 404.2, monoclinic, A2/a, a = 10.1291 (8), b = 5.9038 (5), c = 14.961 (1) A, β = 103.640 (8) 0 , V = 869.5 (1) A 3 , Z = 4, D x = 3.086 Mg m -3 , λ(Mo Kα) = 0.71073 A, μ = 9.86 mm -1 , F(000) = 760, T = 299 K, R(F) = 0.0294 for 1670 unique reflections. K 3 H(SeO 4 ) 2 is isomorphous with most M 3 H(XO 4 ) 2 -type crystals (M=K,Rb and Cs; Cs; X = S and Se); two SeO 4 groups are connected by a crystallographically symmetric hydrogen bond into a dimer. The bond distances and angles in the SeO 4 group are similar to those in Rb 3 H(SeO 4 ) 2 and Rb 3 D(SeO 4 ) 2 . The hydrogen-bond length, 2.524 (5) A, is the shortest among the members of the M 3 H(SeO 4 ) 2 family exhibiting the low-temperature phase transition. (orig.)

Chemical and Electrochemical Asymmetric Dihydroxylation of Olefins in I(2)-K(2)CO(3)-K(2)OsO(2)(OH)(4) and I(2)-K(3)PO(4)/K(2)HPO(4)-K(2)OsO(2)(OH)(4) Systems with Sharpless' Ligand.

Science.gov (United States)

Torii, Sigeru; Liu, Ping; Bhuvaneswari, Narayanaswamy; Amatore, Christian; Jutand, Anny

1996-05-03

Iodine-assisted chemical and electrochemical asymmetric dihydroxylation of various olefins in I(2)-K(2)CO(3)-K(2)OsO(2)(OH)(4) and I(2)-K(3)PO(4)/K(2)HPO(4)-K(2)OsO(2)(OH)(4) systems with Sharpless' ligand provided the optically active glycols in excellent isolated yields and high enantiomeric excesses. Iodine (I(2)) was used stoichiometrically for the chemical dihydroxylation, and good results were obtained with nonconjugated olefins in contrast to the case of potassium ferricyanide as a co-oxidant. The potentiality of I(2) as a co-oxidant under stoichiometric conditions has been proven to be effective as an oxidizing mediator in electrolysis systems. Iodine-assisted asymmetric electro-dihydroxylation of olefins in either a t-BuOH/H(2)O(1/1)-K(2)CO(3)/(DHQD)(2)PHAL-(Pt) or t-BuOH/H(2)O(1/1)-K(3)PO(4)/K(2)HPO(4)/(DHQD)(2)PHAL-(Pt) system in the presence of potassium osmate in an undivided cell was investigated in detail. Irrespective of the substitution pattern, all the olefins afforded the diols in high yields and excellent enantiomeric excesses. A plausible mechanism is discussed on the basis of cyclic voltammograms as well as experimental observations.

New results from T2K

Science.gov (United States)

Longhin, A.

2017-12-01

The T2K experiment is a 295-km long-baseline neutrino experiment in Japan employing an off-axis muon neutrino beam with a 0.6 GeV peak energy. The beam, produced from 30-GeV protons at the J-PARC complex on the Pacific coast, is directed to the Super-Kamiokande detector. T2K released the first long-baseline measurement of a nonzero value for the θ13 mixing parameter through the observation of electron neutrino appearance (vµ → ve) and produced the most precise measurement of θ23 through the observation of muon neutrino disappearance (vµ → vµ). T2K data, in combination with reactor experiments, also excludes at 90% C.L. a significant region of the Dirac CP phase: δCP -0.49(-0.98) for the normal (inverted) hierarchy. A full joint appearance and disappearance fit including both neutrino (7×1020 protons on target, PoT) and anti-neutrino (4 × 1020 PoT) data and, for the first time, a constraint from water target data in the near detector, is presented yielding improved sensitivity on δCP and improved precision on sin2 2θ23 and the atmospheric mass splitting.

The reaction between H2 and O2 over tungsten carbide catalysts

International Nuclear Information System (INIS)

Guskey, G.J.; Boudart, M.; Frennet, A.

1992-01-01

The stationary-state reaction between H 2 and O 2 either in excess H 2 or O 2 has been studied in a flow recirculation reactor over unsupported powders of tungsten carbide with high specific surface area and microporous texture for up to 40 h. Areal rates, v a are first order in the concentration of the limiting reactant and zero order in the concentration of the excess reactant between 273 and 600 K and near atmospheric pressure. Rates are referred to the number of sites counted by titration of preadsorbed oxygen with H 2 at room temperature. This number is multiplied by the surface area per W atom to obtain v a . These tungsten carbides exhibit a microporous structure. A break in the Arrhenius diagram near 450 K is observed. Below 450 K either in excess H 2 or O 2 capillary condensation of product water causes the micropores of the catalyst to become blocked. Thus, the reaction occurs only in the mesopores which account for about 10% of the total specific surface area, S g . Above 450 K, water leaves the micropores and the apparent v a increases as active sites within the micropores become accessible to the reactants. In excess O 2 at 273 K, the first order rate constant of v a based on active area of mesopores, is two times higher for microporous αWC than that for platinum

The Cheshire-cat-like Behavior of 2nu(sub 3) Overtone of Co2 near 2.134 micron: NIR Lab Spectra of Solid CO2 in H2O and CH3OH

Science.gov (United States)

Bernstein, Max; Sandford, Scott; Cruikshank, Dale

2005-01-01

Infrared (IR) spectra have demonstrated that solid H2O is very common in the outer Solar System, and solid carbon dioxide (CO2) has been detected on icy satellites, comets, and planetismals throughout the outer Solar System. In such environments, CO2 and H2O must sometimes be mixed at a molecular level, changing their IR absorption features. In fact, the IR spectra of CO2-H2O mixtures are not equivalent to a linear combination of the spectra of the pure materials. Laboratory IR spectra of pure CO2 and H2O have been published but a lack of near-IR spectra of CO2-H2O mixtures has made the interpretation of outer Solar System spectra more difficult. We present near infrared (IR) spectra of CO2 in H2O and in CH3OH compared to that of pure solid CO2 and find significant differences. Peaks not present in either pure H2O or pure CO2 spectra become evident. First, the CO2 (2nu(sub 3)) overtone near 2.134 micron (4685/ cm) that is not seen in pure solid CO2 is prominent in the spectrum of a CO2/H2O = 25 mixture. Second, a 2.74 micron (3650/ cm) dangling OH feature of water (and a potentially related peak at 1.89 micron) appear in the spectra of CO2-H2O ice mixtures, but may not be specific to the presence of CO2. Other CO2 peaks display shifts in position and increased width because of intermolecular interactions with water. Changes in CO2 peak positions and profiles on warming of a CO2/H2O = 5 mixture are consistent with 'segregation' of the ice into nearly pure separate components. Absolute strengths for absorptions of CO2 in solid H2O are estimated. Similar results are observed for CO2 in solid CH3OH. Since the CO2 ( 2nu(sub 3)) overtone near 2.134 micron (4685/ cm) is not present in pure CO2 but prominent in mixtures it may be a good observational indicator of whether solid CO2 is a pure material or intimately mixed with other molecules. Significant changes in the near IR spectrum of solid CO2 in the presence of H2O and CH3OH means that the abundance of solid CO2 in the

T2K Liquid Argon TPC

Science.gov (United States)

Meregaglia, Anselmo

2006-09-01

A 2 km LAr detector would be an important asset for the T2K experiment since it would play an important part in reducing the systematics and improving the ultimate θ sensitivity. It would also be an important milestone for the LAr TPC technique, providing in-situ R&D and paving the way for future large LAr detectors. Its main features are discussed in this talk.

H2O temperature sensor for low-pressure flames using tunable diode laser absorption near 2.9 νm

KAUST Repository

Li, Sijie

2011-10-19

Making use of a newly available rapid-tuning diode laser operating at wavelengths up to 2.9 νm, an absorption-based temperature sensor was developed for in situ measurements in low-pressure flames. Based on the systematic analysis of H2O vapor transitions in the fundamental vibrational bands (ν1 and ν3) of H2O in the range of 2.5-3.0 νm, an optimal closely-spaced spectral line pair near 2.9 νm was selected for its temperature sensitivity in the range of 1000-2500 K. The narrow-linewidth room-temperature laser was scanned repetitively across these spectral features at 5 kHz, enabling fast, accurate temperature sensing. Use of the temperature sensor was investigated in low-pressure flames supported on a McKenna burner at 15, 25 and 60 Torr. To avoid absorption by the cold gases in the flame edges and the recirculation region between the burner and the vacuum chamber wall, a variable-path in situ probe was designed and an optimal path length was determined to accurately measure the flame centerline temperature. Different flame conditions were investigated to illustrate the potential of this sensor system for sensitive measurements of combustion temperature in low-pressure flames. © 2011 IOP Publishing Ltd.

Potassium ions intercalated into g-C3N4-modified TiO2 nanobelts for the enhancement of photocatalytic hydrogen evolution activity under visible-light irradiation

Science.gov (United States)

Ma, Jian; Zhou, Wei; Tan, Xin; Yu, Tao

2018-05-01

Solar-to-chemical energy conversion is a challenging photochemical reaction for renewable energy storage. In recent decades, photocatalytic H2 evolution has been studied extensively. TiO2 is a well-established semiconductor in the field of photocatalytic H2 production; however, its low efficiency for solar energy utilization, and high photocarrier recombination rate, restrict its photocatalytic efficiency. Here, a series of K-intercalated g-C3N4-modified TiO2 nanobelts (TCN–Kx) with different dosages of K atoms were fabricated using a hydrothermal method followed by a calcination process. XRD, TEM and XPS tests indicate that a tight interfacial connection is formed between K–g-C3N4 and the TiO2 nanobelts. DFT calculations indicated that K dopants prefer to be at the interlayer sites of g-C3N4, suggesting increased charge transfer efficiency. The H2 production efficiency of the TCN–Kx composite materials from water splitting under visible-light irradiation was clearly improved. Steady fluorescence spectroscopy and photocurrent measurements confirmed that the improvement in photocatalytic H2 production activity was due to the superior charge separation and electron transfer efficiency of TCN–Kx composite materials.

Near Detectors based on gas TPCs for neutrino long baseline experiments

CERN Document Server

Blondel, A

2017-01-01

Time Projection Chambers have been used with success for the T2K ND280 near detector and are proposed for an upgrade of the T2K near detector. High pressure TPCs are also being considered for future long-baseline experiments like Hyper-Kamiokande and DUNE. A High Pressure TPC would be a very sensitive detector for the detailed study of neutrino-nucleus interactions, a limiting factor for extracting the ultimate precision in long baseline experiments. The requirements of TPCs for neutrino detectors are quite specific. We propose here the development of state-of-the-art near detectors based on gas TPC: atmospheric pressure TPCs for T2K-II and a high-pressure TPC for neutrino experiments. The project proposed here benefits from a strong involvement of the European (CERN) members of the T2K collaboration and beyond. It is a strongly synergetic precursor of other projects of near detectors using gas TPCs that are under discussion for the long baseline neutrino projects worldwide. It will help maintain and develop...

Near-Infrared [Fe II] and H2 Study of the Galactic Supernova Remnants

Science.gov (United States)

Lee, Yong-Hyun; Koo, Bon-Chul; Lee, Jae-Joon; Jaffe, Daniel T.; Burton, Michael G.; Ryder, Stuart D.

2018-01-01

We have searched for near-infrared (NIR) [Fe II] (1.644 μm) and H2 1-0 S(1) (2.122 μm) emission features associated with Galactic supernova remnants (SNRs) using the narrow-band imaging surveys UWIFE / UWISH2 (UKIRT Widefield Infrared Survey for [Fe II] / H2). Both surveys cover about 180 square degrees of the first Galactic quadrant (7° reversal” phenomenon, i.e., the H2 emission features are detected outside the [Fe II] emission boundary. We carried out high resolution (R~40,000) NIR H- and K-band spectroscopy of the five SNRs showing the [Fe II]-H2 reversal (G11.2-0.3, KES 73, W44, 3C 396, W49B) using IGRINS (Immersion GRating INfrared Spectrograph). Various ro-vibrational H2 lines have been detected, which are used to derive the kinematic distances to the SNRs and to investigate the origin of the H2 emission. The detected H2 lines show broad line width (> 10 km s-1) and line flux ratios of thermal excitation. We discuss the origin of the extended H2 emission features beyond the the [Fe II] emission boundary.

T2K Liquid Argon TPC

International Nuclear Information System (INIS)

Meregaglia, Anselmo

2006-01-01

A 2 km LAr detector would be an important asset for the T2K experiment since it would play an important part in reducing the systematics and improving the ultimate θ 13 sensitivity. It would also be an important milestone for the LAr TPC technique, providing in-situ R and D and paving the way for future large LAr detectors. Its main features are discussed in this talk

Radiation measurements by pn junction InSb detector at the temperature from 4.2 K to 115 K

International Nuclear Information System (INIS)

Kanno, Ikuo; Yoshihara, Fumiki; Nouchi, Ryo; Sugiura, Osamu; Murase, Yasuhiro; Nakamura, Tatsuya; Katagiri, Masaki

2003-01-01

We fabricated the pn junction-type detectors on a p-type InSb substrate. Both sides of the InSb substrate were etched using a mixture of nitric and lactic acids. On the top side surface, Sn and Al were deposited by heat evaporation and then the Sn was diffused into the p-type InSb by lamp annealing and resulted in the n-type layer. Based on the confirmation of the performance of the InSb detector at temperatures of 0.5 K and 4.2 K, we concentrated on the measurement of alpha particles by the pm junction-type InSb detectors at higher operating temperatures of up to 115 K. The InSb detector showed a wide temperature operating range. We can conclude that all of the voltage was induced slowly by the holes at 4.2 K and mainly as a result of electrons at 77 K. (T. Tanaka)

Hydrostatic pressure study of the structural phase transitions and superconductivity in single crystals of (Ba1-xKx)Fe2As2 (x=0 and 0.45) and CaFe2As2

International Nuclear Information System (INIS)

Torikachvili, M.S.; Bud'ko, S.L.; Ni Ni; Canfield, P.C.

2009-01-01

We studied the effect of hydrostatic pressure (P) on the structural phase transitions and superconductivity in the ternary and pseudo-ternary iron arsenides CaFe 2 As 2 , BaFe 2 As 2 , and (Ba 0.55 K 0.45 )Fe 2 As 2 , by means of measurements of electrical resistivity (ρ) in the 1.8-300 K temperature (T) range, pressures up to 20 kbar, and magnetic fields up to 9 T. CaFe 2 As 2 and BaFe 2 As 2 (lightly doped with Sn) display structural phase transitions near 170 and 85 K, respectively, and do not exhibit superconductivity in ambient pressure, while K-doped (Ba 0.55 K 0.45 )Fe 2 As 2 is superconducting for T 2 As 2 is to shift the onset of the crystallographic transformation down in temperature at the rate of ∼-1.04 K/kbar, while shifting the whole ρ(T) curves downward, whereas its effect on superconducting (Ba 0.55 K 0.45 )Fe 2 As 2 is to shift the onset of superconductivity to lower temperatures at the rate of ∼-0.21 K/kbar. The effect of pressure on CaFe 2 As 2 is first to suppress the crystallographic transformation and induce superconductivity with onset near 12 K very rapidly, i.e., for P c2 ) data in (Ba 0.55 K 0.45 )Fe 2 As 2 and CaFe 2 As 2 are discussed.

Two new three-dimensional zinc phosphites templated by piperazine: [H2pip][Zn3(HPO3)4(H2O)2] and K[H2pip]0.5[Zn3(HPO3)4

Science.gov (United States)

Zhang, Xiao; Wang, Guo-Ming; Wang, Zong-Hua; Wang, Ying-Xia; Lin, Jian-Hua

2014-01-01

Two three-dimensional open-framework zinc phosphites with the same organically templated, [H2pip][Zn3(HPO3)4(H2O)2] (1) and K[H2pip]0.5[Zn3(HPO3)4] (2) (pip = piperazine), have been solvothermally synthesized and structurally characterized by IR, elemental analysis, thermogravimetric analysis, powder and single-crystal X-ray diffractions. Compound 1 consists of ZnO4 tetrahedra, [HPO3] pseudopyramids and [ZnO4(H2O)2] octahedra, which are linked through their vertexes to generate three-dimensional architecture with intersecting 8-membered channels along the [1 0 0], [0 0 1] and [1 0 1] directions. Compound 2 is constructed from strictly alternating ZnO4 tetrahedra and [HPO3] pseudopyramids, and exhibits (3,4)-connected inorganic framework with 8-, and 12-membered channels, in which the K+ and diprotonated H2pip2+ extra-framework cations reside, respectively. The coexistence of inorganic K+ and organic piperazine mixed templates in the structure is unique and, to the best of our knowledge, firstly observed in metal-phosphite materials. In addition, the participation of left-handed and right-handed helical chains in construction of the puckered 4.82 sheet structure in 2 is also noteworthy.

The Kepler and K2 Near-Infrared Transit Survey (KNITS)

Science.gov (United States)

Colon, Knicole; Rodriguez, Joseph E.; Barentsen, Geert; Cardoso, Jose Vinicius de Miranda; Vanderburg, Andrew

2018-01-01

NASA's Kepler mission discovered a plethora of transiting exoplanets after observing a single region of the Galaxy for four years. After a second reaction wheel failed, NASA's Kepler spacecraft was repurposed as K2 to observe different fields along the ecliptic in ~80 day campaigns. To date, K2 has discovered ~130 exoplanets along with another ~400 candidates. The exoplanets that have been confirmed or validated from Kepler and K2 have been primarily subject to spectroscopic observations, high-resolution imaging, or statistical methods. However, most of these, along with all the remaining candidate exoplanets, have had no follow-up transit photometry. In addition, recent studies have shown that for single-planet systems, statistical validation alone can be unreliable and additional follow-up observations are required to reveal the true nature of the system. I will present the latest results from an ongoing program to use the 3.5-meter WIYN telescope at Kitt Peak National Observatory for near-infrared transit photometry of Kepler and K2 exoplanets and candidates. Our program of high-precision, high-cadence, high-spatial-resolution near-infrared transit photometry is providing new measurements of the transit ephemerides and planetary radii as well as weeding out false positives lurking within the candidate lists. To date, 25 K2 and 5 Kepler targets have been observed with WIYN. I will also describe upcoming observations with WIYN that will take place in January 2018 as part of a campaign to observe exoplanet transits in the near-infrared simultaneously with the Kepler spacecraft during K2 Campaign 16. Our program ultimately provides a vetted sample of exoplanets that could be targeted in the future by NASA’s James Webb Space Telescope (JWST) and also demonstrates WIYN’s capabilities for observations of exoplanets to be discovered by NASA's all-sky Transiting Exoplanet Survey Satellite (TESS).Data presented herein were obtained at the WIYN Observatory from

Colossal thermoelectric power factor in K_7/8RhO₂

KAUST Repository

Saeed, Yasir; Singh, Nirpendra; Schwingenschlö gl, Udo

2012-01-01

The thermoelectric properties of the layered oxides KxRhO 2 (x = 1/2 and 7/8) are investigated by means of the electronic structure, as determined by ab inito calculations and Boltzmann transport theory. In general, the electronic structure of K x

Thermal stability of polyoxometalate compound of Keggin K8[2-SiW11O39]∙nH2O supported with SiO2

Directory of Open Access Journals (Sweden)

Yunita Sari M A

2017-06-01

Full Text Available Synthesis through sol-gel method and characterization of polyoxometalate compound of K8[b2-SiW11O39]∙nH2O supported with SiO2 have been done. The functional groups of polyoxometalate compound  was characterized by FT-IR spectrophotometer for the fungtional groups and the degree’s of crystalinity  using XRD. The acidity of K8[b2-SiW11O39]∙nH2O/SiO2 was determined qualitative analysis using ammonia and pyridine adsorption and the quantitative analysis using potentiometric titration method. The results of FT-IR spectrum of K8[b2-SiW11O39]∙nH2O appeared at  wavenumber 987.55 cm-1 (W=O, 864.11 cm-1 (W-Oe-W, 756.1 cm-1 (W-Oc-W, 3425.58 cm-1 (O-H, respectively and spectrum of  K8[b2-SiW11O39]SiO2 appeared at wavenumber  956.69 cm-1 (W=O, 864.11 cm-1 (W-Oe-W, 3448.72 cm-1 (O-H, respectively. The diffraction of XRD pattern of K8[b2-SiW11O39]∙nH2O and K8[b2-SiW11O39]∙nH2O/SiO2 compounds show high crystalinity. The acidic properties showed K8[b2-SiW11O39]∙nH2O/SiO2 more acidic compared to K8[b2-The SiW11O39]∙nH2O. The qualitative analysis showed pyridine compound adsorbed more of polyoxometalate compound of K8[b2-SiW11O39]∙nH2O/SiO2. Analysis of stability showed that the K8[b2-SiW11O39]∙nH2O/SiO2 at temperature 500°C has structural changes compare to 200-400oC which was indicated from vibration at wavenumber 800-1000 cm-1. Keywords : K8[b2-SiW11O39]∙nH2O, polyoxometalate, SiO2.

Experimental determination of the lateral dose response functions of detectors to be applied in the measurement of narrow photon-beam dose profiles.

Science.gov (United States)

Poppinga, D; Meyners, J; Delfs, B; Muru, A; Harder, D; Poppe, B; Looe, H K

2015-12-21

This study aims at the experimental determination of the detector-specific 1D lateral dose response function K(x) and of its associated rotational symmetric counterpart K(r) for a set of high-resolution detectors presently used in narrow-beam photon dosimetry. A combination of slit-beam, radiochromic film, and deconvolution techniques served to accomplish this task for four detectors with diameters of their sensitive volumes ranging from 1 to 2.2 mm. The particular aim of the experiment was to examine the existence of significant negative portions of some of these response functions predicted by a recent Monte-Carlo-simulation (Looe et al 2015 Phys. Med. Biol. 60 6585-607). In a 6 MV photon slit beam formed by the Siemens Artiste collimation system and a 0.5 mm wide slit between 10 cm thick lead blocks serving as the tertiary collimator, the true cross-beam dose profile D(x) at 3 cm depth in a large water phantom was measured with radiochromic film EBT3, and the detector-affected cross-beam signal profiles M(x) were recorded with a silicon diode, a synthetic diamond detector, a miniaturized scintillation detector, and a small ionization chamber. For each detector, the deconvolution of the convolution integral M(x)  =  K(x)  ∗  D(x) served to obtain its specific 1D lateral dose response function K(x), and K(r) was calculated from it. Fourier transformations and back transformations were performed using function approximations by weighted sums of Gaussian functions and their analytical transformation. The 1D lateral dose response functions K(x) of the four types of detectors and their associated rotational symmetric counterparts K(r) were obtained. Significant negative curve portions of K(x) and K(r) were observed in the case of the silicon diode and the diamond detector, confirming the Monte-Carlo-based prediction (Looe et al 2015 Phys. Med. Biol. 60 6585-607). They are typical for the perturbation of the secondary electron field by a detector with

Study of the expected performance of the T2K experiment on muon neutrino to electron neutrino oscillation using data from K2K experiment; Determination des performances attendues sur la recherche de l'oscillation {nu}{sub {mu}} {yields} {nu}{sub e} dans l'experience T2K depuis l'etude des donnees recueillies dans l'experience K2K

Energy Technology Data Exchange (ETDEWEB)

Fechner, M

2006-05-15

T2K is a neutrino oscillation experiment that will use the intense 2.5 degrees off-axis {nu}{sub {mu}} beam produced at J-PARC (Japan). The far detector is Super-Kamiokande (SK), the 50 kt water Cherenkov detector located 295 km from J-PARC. The goal is to search for {nu}{sub e} appearance, which will bring new information on {theta}{sub 13}. The main background for {nu}{sub e} appearance comes from intrinsic beam {nu}{sub e} events ({approx} 55%), and from mis-identified neutral current {pi}{sup 0} events ({approx} 45%); near detectors are needed to measure these background components before oscillation. A detector complex (2KM) including a water Cherenkov detector, located {approx} 1.8 km away from the source is under active study. This distance is advantageous because the neutrino spectrum is only a few percent different from that of SK, thereby reducing extrapolation systematics. In order to match SK performance, the water Cherenkov detector was designed with {approx} 5600 8-inch photo-multiplier tubes, after studies based on full simulation tuned to K2K data. The water Cherenkov reconstruction algorithms, mainly particle identification and e/{pi}{sup 0} separation, were also studied at 2KM. Studies of {nu}{sub e} appearance in the water Cherenkov detector show that using simple scaling extrapolation we conservatively predict 23.0 {+-} 8.0% (stat + syst) background events at SK for 5. 10{sup 21} p.o.t., in excellent agreement with the 23.8 background events obtained from an independent simulation of SK. The 2KM detector can achieve background subtraction to better than 10% accuracy, sufficient for T2K phase I. Detailed sensitivity studies, including all the relevant sources of systematics, show that the 2KM detector improves the sensitivity to sin{sup 2}(2{theta}{sub 13}) down to {approx} 1.4. 10{sup -2} at 90% CL. (author)

Scintillator counters with multi-pixel avalanche photodiode readout for the ND280 detector of the T2K experiment

International Nuclear Information System (INIS)

Mineev, O.; Afanasjev, A.; Bondarenko, G.; Golovin, V.; Gushchin, E.; Izmailov, A.; Khabibullin, M.; Khotjantsev, A.; Kudenko, Yu.; Kurimoto, Y.; Kutter, T.; Lubsandorzhiev, B.; Mayatski, V.; Musienko, Yu.; Nakaya, T.; Nobuhara, T.; Shaibonov, B.A.J.; Shaikhiev, A.; Taguchi, M.; Yershov, N.; Yokoyama, M.

2007-01-01

The Tokai-to-Kamioka (T2K) experiment is a second generation long baseline neutrino oscillation experiment which aims at a sensitive search for ν e appearance. The main design features of the T2K near neutrino detectors located at 280m from the target are presented, and the scintillator counters are described. The counters are readout via WLS fibers embedded into S-shaped grooves in the scintillator from both ends by multi-pixel avalanche photodiodes operating in a limited Geiger mode. Operating principles and results of tests of photosensors with a sensitive area of 1mm 2 are presented. A time resolution of 1.75ns, a spatial resolution of 9.9-12.4cm, and a detection efficiency for minimum ionizing particles of more than 99% were obtained for scintillator detectors in a beam test

Preclinical efficacy of the MDM2 inhibitor RG7112 in MDM2 amplified and TP53 wild-type glioblastomas

Science.gov (United States)

Verreault, Maite; Schmitt, Charlotte; Goldwirt, Lauriane; Pelton, Kristine; Haidar, Samer; Levasseur, Camille; Guehennec, Jeremy; Knoff, David; Labussiere, Marianne; Marie, Yannick; Ligon, Azra H.; Mokhtari, Karima; Hoang-Xuan, Khe; Sanson, Marc; Alexander, Brian M; Wen, Patrick Y.; Delattre, Jean-Yves; Ligon, Keith L.; Idbaih, Ahmed

2016-01-01

Rationale p53 pathway alterations are key molecular events in glioblastoma (GBM). MDM2 inhibitors increase expression and stability of p53 and are presumed to be most efficacious in patients with TP53 wild-type and MDM2-amplified cancers. However, this biomarker hypothesis has not been tested in patients or patient-derived models for GBM. Methods We performed a preclinical evaluation of RG7112 MDM2 inhibitor, across a panel of 36 patient-derived GBM cell lines (PDCLs), each genetically characterized according to their P53 pathway status. We then performed a pharmacokinetic (PK) profiling of RG7112 distribution in mice and evaluated the therapeutic activity of RG7112 in orthotopic and subcutaneous GBM models. Results MDM2-amplified PDCLs were 44 times more sensitive than TP53 mutated lines that showed complete resistance at therapeutically attainable concentrations (avg. IC50 of 0.52 μM vs 21.9 μM). MDM4 amplified PDCLs were highly sensitive but showed intermediate response (avg. IC50 of 1.2 μM), whereas response was heterogeneous in TP53 wild-type PDCLs with normal MDM2/4 levels (avg. IC50 of 7.7 μM). In MDM2-amplified lines, RG7112 restored p53 activity inducing robust p21 expression and apoptosis. PK profiling of RG7112-treated PDCL intracranial xenografts demonstrated that the compound significantly crosses the blood-brain and the blood-tumor barriers. Most importantly, treatment of MDM2-amplified/TP53 wild-type PDCL-derived model (subcutaneous and orthotopic) reduced tumor growth, was cytotoxic, and significantly increased survival. Conclusion These data strongly support development of MDM2 inhibitors for clinical testing in MDM2-amplified GBM patients. Moreover, significant efficacy in a subset of non-MDM2 amplified models suggests that additional markers of response to MDM2 inhibitors must be identified. PMID:26482041

1H and 2H NMR relaxation study on the phase transitions of (NH4)3H(SO4)2 and (ND4)3D(SO4)2 single crystals

International Nuclear Information System (INIS)

Lim, Ae Ran; Jeong, Se-Young

2006-01-01

T 1 , T 1ρ and T 2 for the 1 H and 2 H nuclei in (NH 4 ) 3 H(SO 4 ) 2 and (ND 4 ) 3 D(SO 4 ) 2 single crystals grown using the slow evaporation method were measured for phases I, II, III, IV and V. The 1 H T 1 , T 1ρ , and T 2 values were found to exhibit different trends in phases II and III: T 1 , T 1ρ and T 2 for 1 H do not change significantly near the phase transition at 265 K, whereas near 413 K they change discontinuously. We conclude that the NH 4 + and H(SO 4 ) 2 - ions do not play an important role in the III-II phase transition, but do play important roles in the II-I phase transition. The liquid-like nature of the 1 H T 1ρ and T 2 above 413 K is indicative of the destruction and reconstruction of hydrogen bonds. Moreover, the phase transitions of the (NH 4 ) 3 H(SO 4 ) 2 crystal are accompanied by changes in the molecular motion of the (NH 4 ) + ions. The variations with temperature of the 2 H T 1 and T 2 of (ND 4 ) 3 D(SO 4 ) 2 crystals are not similar to those observed for the 1 H T 1 and T 2 . Our comparison of the results for (NH 4 ) 3 H(SO 4 ) 2 and (ND 4 ) 3 D(SO 4 ) 2 crystals indicates the following: the 1 H T 1ρ and T 2 of the (NH 4 ) + and H(SO 4 ) 2 - ions above T C1 are characteristic of fast, liquid-like motion, which is not the case for (ND 4 ) 3 D(SO 4 ) 2 ; and the 2 H T 1 of D(SO 4 ) 2 - in (ND 4 ) 3 D(SO 4 ) 2 is longer than the 2 H T 1 of (ND 4 ) + in contrast to the results for (NH 4 ) 3 H(SO 4 ) 2 crystals

Radiation and drug response of the rat glioma RG2

International Nuclear Information System (INIS)

Weizsaecker, M.; Nagamune, A.; Winkelstroeter, R.; Vieten, H.; Wechsler, W.

1982-01-01

A clonogenic cell assay was developed for the chemically induced rat glioma RG2 that allows in vivo, in vitro, and in vivo to in vitro studies of cell survival after experimental therapy. RG2 monolayer cells were resistant to BCNU up to high concentrations. The x-radiation survival curves were characterized by a D 0 of 2.4 gray and n = 2.2 for monolayer cells, a D 0 of 3.5 gray and n = 1.3 for cells irradiated as brain tumors in air-breathing rats, and a D 0 of 5.9 gray and n = 1.2 for cells irradiated as brain tumors in nitrogen-asphyxiated rats. There was no evidence of a radiobiologically hypoxic fraction of cells in the brain tumors, but their radiosensitivity was definitely smaller than that of monolayer cells. (author)

H2O2 Synthesis Induced by Irradiation of H2O with Energetic H(+) and Ar(+) Ions at Various Temperatures

Science.gov (United States)

Baragiola, R. A.; Loeffler, M. J.; Raut, U.; Vidal, R. A.; Carlson, R. W.

2004-01-01

The detection of H2O2 on Jupiter's icy satellite Europa by the Galileo NIMS instrument presented a strong evidence for the importance of radiation effects on icy surfaces. A few experiments have investigated whether solar flux of protons incident on Europa ice could cause a significant if any H2O2 production. These published results differ as to whether H2O2 can be formed by ions impacting water at temperatures near 80 K, which are appropriate to Europa. This discrepancy may be a result of the use of different incident ion energies, different vacuum conditions, or different ways of processing the data. The latter possibility comes about from the difficulty of identifying the 3.5 m peroxide OH band on the long wavelength wing of the much stronger water 3.1 m band. The problem is aggravated by using straight line baselines to represent the water OH band with a curvature, in the region of the peroxide band, that increases with temperature. To overcome this problem, we use polynomial baselines that provide good fits to the water band and its derivative.

MHC class I Dk locus and Ly49G2+ NK cells confer H-2k resistance to murine cytomegalovirus.

Science.gov (United States)

Xie, Xuefang; Stadnisky, Michael D; Brown, Michael G

2009-06-01

Essential NK cell-mediated murine CMV (MCMV) resistance is under histocompatibility-2(k) (H-2(k)) control in MA/My mice. We generated a panel of intra-H2(k) recombinant strains from congenic C57L.M-H2(k/b) (MCMV resistant) mice for precise genetic mapping of the critical interval. Recombination breakpoint sites were precisely mapped and MCMV resistance/susceptibility traits were determined for each of the new lines to identify the MHC locus. Strains C57L.M-H2(k)(R7) (MCMV resistant) and C57L.M-H2(k)(R2) (MCMV susceptible) are especially informative; we found that allelic variation in a 0.3-megabase interval in the class I D locus confers substantial difference in MCMV control phenotypes. When NK cell subsets responding to MCMV were examined, we found that Ly49G2(+) NK cells rapidly expand and selectively acquire an enhanced capacity for cytolytic functions only in C57L.M-H2(k)(R7). We further show that depletion of Ly49G2(+) NK cells before infection abrogated MCMV resistance in C57L.M-H2(k)(R7). We conclude that the MHC class I D locus prompts expansion and activation of Ly49G2(+) NK cells that are needed in H-2(k) MCMV resistance.

Industrial production of MgH2 and its application

International Nuclear Information System (INIS)

Uesugi, H.; Sugiyama, T.; Nii, H.; Ito, T.; Nakatsugawa, I.

2011-01-01

Research highlights: → Tablet and powder Mg were hydrogenated in a 50 kg batch furnace based on thermal equilibrium method. → Compression of Mg tablet improved the hydrogenation yield. → Hydrolysis of MgH 2 using citric acid generated hydrogen under 373 K. → A MgH 2 -hydrogen reactor utilizing hydraulic head pressure was developed. → - Abstract: A process for the industrial production of magnesium hydride (MgH 2 ) based on a thermal equilibrium method and its application to portable hydrogen sources is proposed. Mg powders and tablets compressed with mechanically ground Mg ribbons were successfully hydrogenated in a 50-kg-batch furnace. The resultant MgH 2 showed a hydrogen yield of around 96% with good reproducibility. The compression ratio of Mg tablets was found to be an important factor in the hydrogenation yield. A hydrolysis technique using citric acid as an additive was employed to generate hydrogen under 373 K. Increasing the concentration of citric acid and the temperature accelerated the hydrolysis reactivity. A hydrogen reactor utilizing hydraulic head pressure was developed. It generated hydrogen continuously for 1 h at a flow rate of 100 ml min -1 with hydrolysis of 5 g of tablet-form MgH 2 . The conversion yield was around 70%, regardless of the flow rate.

HM{sup +}–RG complexes (M = group 2 metal; RG = rare gas): Physical vs. chemical interactions

Energy Technology Data Exchange (ETDEWEB)

Harris, Joe P.; Dodson, Hannah; Wright, Timothy G., E-mail: Tim.Wright@nottingham.ac.uk [School of Chemistry, University of Nottingham, University Park, Nottingham NG7 2RD (United Kingdom); Breckenridge, W. H. [Department of Chemistry, University of Utah, Salt Lake City, Utah 84112 (United States)

2015-04-21

Previous work on the HM{sup +}–He complexes (M = Be–Ra) has been extended to the cases of the heavier rare gas atoms, HM{sup +}–RG (RG = Ne–Rn). Optimized geometries and harmonic vibrational frequencies have been calculated using MP2 theory and quadruple-ζ quality basis sets. Dissociation energies for the loss of the rare gas atom have been calculated at these optimized geometries using coupled cluster with single and double excitations and perturbative triples, CCSD(T)theory, extrapolating interaction energies to the basis set limit. Comparisons are made between the present data and the previously obtained helium results, as well as to those of the bare HM{sup +} molecules; furthermore, comparisons are made to the related M{sup +}–RG and M{sup 2+}–RG complexes. Partial atomic charge analyses have also been undertaken, and these used to test a simple charge-induced dipole model. Molecular orbital diagrams are presented together with contour plots of the natural orbitals from the quadratic configuration with single and double excitations (QCISD) density. The conclusion is that the majority of these complexes are physically bound, with very little sharing of electron density; however, for M = Be, and to a lesser extent M = Mg, some evidence for chemical effects is seen in HM{sup +}–RG complexes involving RG atoms with the higher atomic numbers.

[Analysis of H2S/PH3/NH3/AsH3/Cl2 by Full-Spectral Flame Photometric Detector].

Science.gov (United States)

Ding, Zhi-jun; Wang, Pu-hong; Li, Zhi-jun; Du, Bin; Guo, Lei; Yu, Jian-hua

2015-07-01

Flame photometric analysis technology has been proven to be a rapid and sensitive method for sulfur and phosphorus detection. It has been widely used in environmental inspections, pesticide detection, industrial and agricultural production. By improving the design of the traditional flame photometric detector, using grating and CCD sensor array as a photoelectric conversion device, the types of compounds that can be detected were expanded. Instead of a single point of characteristic spectral lines, full spectral information has been used for qualitative and quantitative analysis of H2S, PH3, NH3, AsH3 and Cl2. Combined with chemometric method, flame photometric analysis technology is expected to become an alternative fast, real-time on-site detection technology to simultaneously detect multiple toxic and harmful gases.

Results from K2K experiment

International Nuclear Information System (INIS)

Yanagisawa, Chiaki

2001-01-01

The K2K experiment is the first long baseline neutrino oscillation experiment at KEK and at Kamioka, Japan. This is a brief summary of the K2K experiment in the first year of running from June 1999 to June 2000. The major result is that for the first time in human history artificially produced neutrinos by an accelerator are detected at a long distance of 250km from the production points. A brief introduction, the detector performance and the some analysis results are presented. The analysis results are based on the data corresponding to the integrated beam intesnsity of 2.29 x 10 19 pot

Direct measurements of rate constants for the reactions of CH3 radicals with C2H6, C2H4, and C2H2 at high temperatures.

Science.gov (United States)

Peukert, S L; Labbe, N J; Sivaramakrishnan, R; Michael, J V

2013-10-10

The shock tube technique has been used to study the reactions CH3 + C2H6 → C2H4 + CH4 + H (1), CH3 + C2H4 → Products + H (2), and CH3 + C2H2 → Products + H (3). Biacetyl, (CH3CO)2, was used as a clean high temperature thermal source for CH3-radicals for all the three reactions studied in this work. For reaction 1, the experiments span a T-range of 1153 K ≤ T ≤ 1297 K, at P ~ 0.4 bar. The experiments on reaction 2 cover a T-range of 1176 K ≤ T ≤ 1366 K, at P ~ 1.0 bar, and those on reaction 3 a T-range of 1127 K ≤ T ≤ 1346 K, at P ~ 1.0 bar. Reflected shock tube experiments performed on reactions 1-3, monitored the formation of H-atoms with H-atom Atomic Resonance Absorption Spectrometric (ARAS). Fits to the H-atom temporal profiles using an assembled kinetics model were used to make determinations for k1, k2, and k3. In the case of C2H6, the measurements of [H]-atoms were used to derive direct high-temperature rate constants, k1, that can be represented by the Arrhenius equation k1(T) = 5.41 × 10(-12) exp(-6043 K/T) cm(3) molecules(-1) s(-1) (1153 K ≤ T ≤ 1297 K) for the only bimolecular process that occurs, H-atom abstraction. TST calculations based on ab initio properties calculated at the CCSD(T)/CBS//M06-2X/cc-pVTZ level of theory show excellent agreement, within ±20%, of the measured rate constants. For the reaction of CH3 with C2H4, the present rate constant results, k2', refer to the sum of rate constants, k(2b) + k(2c), from two competing processes, addition-elimination, and the direct abstraction CH3 + C2H4 → C3H6 + H (2b) and CH3 + C2H4 → C2H2 + H + CH4 (2c). Experimental rate constants for k2' can be represented by the Arrhenius equation k2'(T) = 2.18 × 10(-10) exp(-11830 K/T) cm(3) molecules(-1) s(-1) (1176 K ≤ T ≤ 1366 K). The present results are in excellent agreement with recent theoretical predictions. The present study provides the only direct measurement for the high-temperature rate constants for these channels

Relativity-Induced Bonding Pattern Change in Coinage Metal Dimers M2 (M = Cu, Ag, Au, Rg).

Science.gov (United States)

Li, Wan-Lu; Lu, Jun-Bo; Wang, Zhen-Ling; Hu, Han-Shi; Li, Jun

2018-05-07

The periodic table provides a fundamental protocol for qualitatively classifying and predicting chemical properties based on periodicity. While the periodic law of chemical elements had already been rationalized within the framework of the nonrelativistic description of chemistry with quantum mechanics, this law was later known to be affected significantly by relativity. We here report a systematic theoretical study on the chemical bonding pattern change in the coinage metal dimers (Cu 2 , Ag 2 , Au 2 , Rg 2 ) due to the relativistic effect on the superheavy elements. Unlike the lighter congeners basically demonstrating ns- ns bonding character and a 0 g + ground state, Rg 2 shows unique 6d-6d bonding induced by strong relativity. Because of relativistic spin-orbit (SO) coupling effect in Rg 2 , two nearly degenerate SO states, 0 g + and 2 u , exist as candidate of the ground state. This relativity-induced change of bonding mechanism gives rise to various unique alteration of chemical properties compared with the lighter dimers, including higher intrinsic bond energy, force constant, and nuclear shielding. Our work thus provides a rather simple but clear-cut example, where the chemical bonding picture is significantly changed by relativistic effect, demonstrating the modified periodic law in heavy-element chemistry.

Protection of White Leghorn chickens by U.S. emergency H5 vaccination against clade 2.3.4.4 H5N2 high pathogenicity avian influenza virus.

Science.gov (United States)

Bertran, Kateri; Balzli, Charles; Lee, Dong-Hun; Suarez, David L; Kapczynski, Darrell R; Swayne, David E

2017-11-01

During December 2014-June 2015, the U.S. experienced a high pathogenicity avian influenza (HPAI) outbreak caused by clade 2.3.4.4 H5Nx Goose/Guangdong lineage viruses with devastating consequences for the poultry industry. Three vaccines, developed based on updating existing registered vaccines or currently licensed technologies, were evaluated for possible use: an inactivated reverse genetics H5N1 vaccine (rgH5N1) and an RNA particle vaccine (RP-H5), both containing the hemagglutinin gene of clade 2.3.4.4 strain, and a recombinant herpesvirus turkey vectored vaccine (rHVT-H5) containing the hemagglutinin gene of clade 2.2 strain. The efficacy of the three vaccines, alone or in combination, was assessed in White Leghorn chickens against clade 2.3.4.4 H5N2 HPAI virus challenge. In Study 1, single (rHVT-H5) and prime-boost (rHVT-H5+rgH5N1 or rHVT-H5+RP-H5) vaccination strategies protected chickens with high levels of protective immunity and significantly reduced virus shedding. In Study 2, single vaccination with either rgH5N1 or RP-H5 vaccines provided clinical protection in adult chickens and significantly reduced virus shedding. In Study 3, double rgH5N1 vaccination protected adult chickens from clinical signs and mortality when challenged 20weeks post-boost, with high levels of long-lasting protective immunity and significantly reduced virus shedding. These studies support the use of genetically related vaccines, possibly in combination with a broad protective priming vaccine, for emergency vaccination programs against clade 2.3.4.4 H5Nx HPAI virus in young and adult layer chickens. Published by Elsevier Ltd.

Identification and characterization of a ginsenoside-transforming β-glucosidase from Pseudonocardia sp. Gsoil 1536 and its application for enhanced production of minor ginsenoside Rg2(S.

Directory of Open Access Journals (Sweden)

Juan Du

Full Text Available The ginsenoside Rg2(S, which is one of the pharmaceutical components of ginseng, is known to have neuroprotective, anti-inflammation, and anti-diabetic effects. However, the usage of ginsenoside Rg2(S is restricted owing to the small amounts found in white and red ginseng. To enhance the production of ginsenoside Rg2(S as a 100 gram unit with high specificity, yield, and purity, an enzymatic bioconversion method was developed to adopt the recombinant glycoside hydrolase (BglPC28, which is a ginsenoside-transforming recombinant β-glucosidase from Pseudonocardia sp. strain Gsoil 1536. The gene, termed bglPC28, encoding β-glucosidase (BglPC28 belonging to the glycoside hydrolase family 3 was cloned. bglPC28 consists of 2,232 bp (743 amino acid residues with a predicted molecular mass of 78,975 Da. This enzyme was overexpressed in Escherichia coli BL21(DE3 using a GST-fused pGEX 4T-1 vector system. The optimum conditions of the recombinant BglPC28 were pH 7.0 and 37 °C. BglPC28 can effectively transform the ginsenoside Re to Rg2(S; the Km values of PNPG and Re were 6.36 ± 1.10 and 1.42 ± 0.13 mM, respectively, and the Vmax values were 40.0 ± 2.55 and 5.62 ± 0.21 µmol min-1 mg-1 of protein, respectively. A scaled-up biotransformation reaction was performed in a 10 L jar fermenter at pH 7.0 and 30°C for 12 hours with a concentration of 20 mg/ml of ginsenoside Re from American ginseng roots. Finally, 113 g of Rg2(S was produced from 150 g of Re with 84.0 ± 1.1% chromatographic purity. These results suggest that this enzymatic method could be usefully exploited in the preparation of ginsenoside Rg2(S in the cosmetics, functional food, and pharmaceutical industries.

First identification and thermodynamic characterization of the ternary U(VI) species, UO2(O2)(CO3)2(4-), in UO2-H2O2-K2CO3 solutions.

Science.gov (United States)

Goff, George S; Brodnax, Lia F; Cisneros, Michael R; Peper, Shane M; Field, Stephanie E; Scott, Brian L; Runde, Wolfgang H

2008-03-17

In alkaline carbonate solutions, hydrogen peroxide can selectively replace one of the carbonate ligands in UO2(CO3)3(4-) to form the ternary mixed U(VI) peroxo-carbonato species UO2(O2)(CO3)2(4-). Orange rectangular plates of K4[UO2(CO3)2(O2)].H2O were isolated and characterized by single crystal X-ray diffraction studies. Crystallographic data: monoclinic, space group P2(1)/ n, a = 6.9670(14) A, b = 9.2158(10) A, c = 18.052(4) A, Z = 4. Spectrophotometric titrations with H 2O 2 were performed in 0.5 M K 2CO 3, with UO2(O2)(CO3)2(4-) concentrations ranging from 0.1 to 0.55 mM. The molar absorptivities (M(-1) cm(-1)) for UO2(CO3)3(4-) and UO2(O2)(CO3)2(4-) were determined to be 23.3 +/- 0.3 at 448.5 nm and 1022.7 +/- 19.0 at 347.5 nm, respectively. Stoichiometric analyses coupled with spectroscopic comparisons between solution and solid state indicate that the stable solution species is UO2(O2)(CO3)2(4-), which has an apparent formation constant of log K' = 4.70 +/- 0.02 relative to the tris-carbonato complex.

A calorimetric and thermodynamic investigation of A2[(UO2)2(MoO4)O2] compounds with A = K and Rb and calculated phase relations in the system (K2MoO4 + UO3 + H2O)

International Nuclear Information System (INIS)

Lelet, Maxim I.; Suleimanov, Evgeny V.; Golubev, Aleksey V.; Geiger, Charles A.; Bosbach, Dirk; Alekseev, Evgeny V.

2015-01-01

Highlights: • We determined the low temperature heat capacity of A 2 [(UO 2 ) 2 (MoO 4 )O 2 ] compounds with A = K and Rb. • We determined enthalpy of formation of K 2 [(UO 2 ) 2 (MoO 4 )O 2 ] by HF solution calorimetry. • We calculated Δ f G° (T = 298 K) of all phases from studied series. • Using obtained data we performed a thermodynamic modelling in the system (K 2 MoO 4 + UO 3 + H 2 O). - Abstract: A calorimetric and thermodynamic investigation of two alkali-metal uranyl molybdates with general composition A 2 [(UO 2 ) 2 (MoO 4 )O 2 ], where A = K and Rb, was performed. Both phases were synthesized by solid-state sintering of a mixture of potassium or rubidium nitrate, molybdenum (VI) oxide and gamma-uranium (VI) oxide at high temperatures. The synthetic products were characterised by X-ray powder diffraction and X-ray fluorescence methods. The enthalpy of formation of K 2 [(UO 2 ) 2 (MoO 4 )O 2 ] was determined using HF-solution calorimetry giving Δ f H° (T = 298 K, K 2 [(UO 2 ) 2 (MoO 4 )O 2 ], cr) = −(4018 ± 8) kJ · mol −1 . The low-temperature heat capacity, C p °, was measured using adiabatic calorimetry from T = (7 to 335) K for K 2 [(UO 2 ) 2 (MoO 4 )O 2 ] and from T = (7 to 326) K for Rb 2 [(UO 2 ) 2 (MoO 4 )O 2 ]. Using these C p ° values, the third law entropy at T = 298.15 K, S°, is calculated as (374 ± 1) J · K −1 · mol −1 for K 2 [(UO 2 ) 2 (MoO 4 )O 2 ] and (390 ± 1) J · K −1 · mol −1 for Rb 2 [(UO 2 ) 2 (MoO 4 )O 2 ]. These new experimental results, together with literature data, are used to calculate the Gibbs energy of formation, Δ f G°, for both phases giving: Δ f G° (T = 298 K, K 2 [(UO 2 ) 2 (MoO 4 )O 2 ], cr) = (−3747 ± 8) kJ · mol −1 and Δ f G° (T = 298 K, Rb 2 [(UO 2 ) 2 (MoO 4 )], cr) = −3736 ± 5 kJ · mol −1 . Smoothed C p °(T) values between 0 K and 320 K are presented, along with values for S° and the functions [H°(T) − H°(0)] and [G°(T) − H°(0)], for both phases. The

Micropore Formation of [Zn2(Oxac) (Taz)2]·(H2O)2.5 via CO2 Adsorption.

Science.gov (United States)

Zubir, Moondra; Hamasaki, Atom; Iiyama, Taku; Ohta, Akira; Ohki, Hiroshi; Ozeki, Sumio

2017-01-24

As-synthesized [Zn 2 (Oxac) (Taz) 2 ]·(H 2 O) 2.5 , referred to as ZOTW 2.5 , was prepared from aqueous methanol solutions of Zn 5 (CO 3 ) 2 (OH) 6 and two kinds of ligands of 1,2,4-triazole (Taz) and oxalic acid (Oxac) at 453 K for 12 h. The crystal structure was determined by the Rietveld method. As-synthesized ZOTW 2.5 was pretreated at 383 K and 1 mPa for t pt h, ZOTW x (t pt h). ZOTW x (≥3h) showed a type I adsorption isotherm for N 2 at 77 K having a saturation amount (V s ) of 180 mg/g, but that pretreated shortly showed only 1/10 in V s . CO 2 was adsorbed at 303 K in sigmoid on nonporous ZOTW x (≤2h) and in Langmuir-type on ZOTW x (≥3h) to reach the adsorption amount of 120 mg/g at 700 Torr. N 2 adsorption on ZOTW x (≤2h)deCO 2 , degassed after CO 2 adsorption on ZOTW x (≤2h), was promoted 5-fold from 180 mg/g on ZOTW x (t pt h) and ZOTW x (≥3h)deCO 2 up to ca. 1000 mg/g. The interaction of CO 2 and H 2 O molecules in micropores may lead to a new route for micropore formation.

Systems Li[sub 2]B[sub 4]O[sub 7] (Na[sub 2]B[sub 4]O[sub 7], K[sub 2]B[sub 4]O[sub 7])-N[sub 2]H[sub 3]H[sub 4]OH-H[sub 2]O at 25 deg C. Sistemy Li[sub 2]B[sub 4]O[sub 7] (Na[sub 2]B[sub 4]O[sub 7], K[sub 2]B[sub 4]O[sub 7])-N[sub 2]H[sub 3]H[sub 4]OH-H[sub 2]O pri 25 grad S

Energy Technology Data Exchange (ETDEWEB)

Skvortsov, V G; Sadetdinov, Sh V; Akimov, V M; Mitrasov, Yu N; Petrova, O V; Klopov, Yu N [Chuvashskij Gosudarstvennyj Pedagogicheskij Inst., Cheboksary (Russian Federation) Universitet Druzhby Narodov, Moscow (Russian Federation)

1994-02-01

Phase equilibriums in the Li[sub 2]B[sub 4]O[sub 7] (Na[sub 2]B[sub 4]O[sub 7], K[sub 2]B[sub 4]O[sub 7])-N[sub 2]H[sub 3]H[sub 4]OH-H[sub 2]O systems were investigated by methods of isothermal solubility, refractometry and PH-metry at 25 deg C for the first time. Lithium and sodium tetraborates was established to form phases of changed composition mM[sub 2]B[sub 4]O[sub 7][center dot]nN[sub 2]H[sub 3]C[sub 2]H[sub 4]OH[center dot]XH[sub 2]O, where M=Li, Na with hydrazine ethanol. K[sub 2]B[sub 4]O[sub 7][center dot]4H[sub 2]O precipitates in solid phase in the case of potassium salt. Formation of isomorphous mixtures was supported by X-ray diffraction and IR spectroscopy methods.

CaK2(AsO3OH)(H2O)2 cell length a | forthcoming | boms | Volumes ...

Indian Academy of Sciences (India)

Home; public; Volumes; boms; forthcoming; CaK2(AsO3OH)(H2O)2 cell length a. 404! error. The page your are looking for can not be found! Please check the link or use the navigation bar at the top. YouTube; Twitter; Facebook; Blog. Academy News. IAS Logo. 29th Mid-year meeting. Posted on 19 January 2018. The 29th ...

Experimental determination and modeling of the solubility phase diagram of the ternary system (Li{sub 2}SO{sub 4} + K{sub 2}SO{sub 4} + H{sub 2}O) at 288.15 K

Energy Technology Data Exchange (ETDEWEB)

Wang, Shiqiang, E-mail: wangshiqiang@tust.edu.cn [Tianjin Key Laboratory of Marine Resources and Chemistry, College of Marine Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457 (China); Guo, Yafei [Tianjin Key Laboratory of Marine Resources and Chemistry, College of Marine Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457 (China); Li, Dongchan [Engineering Research Center of Seawater Utilization Technology of Ministry of Education, Hebei University of Technology, Tianjin 300130 (China); Tang, Peng; Deng, Tianlong [Tianjin Key Laboratory of Marine Resources and Chemistry, College of Marine Science and Engineering, Tianjin University of Science and Technology, Tianjin 300457 (China)

2015-02-10

Highlights: • Solubility of the ternary system Li{sub 2}SO{sub 4} + K{sub 2}SO{sub 4} + H{sub 2}O at 288.15 K has been measured. • Phase diagram of this system was simulated and calculated by a thermodynamic model. • Li{sub 2}SO{sub 4}·K{sub 2}SO{sub 4} belongs to the incongruent double salt in this system. • Solution density was calculated using empirical equation. - Abstract: The solubility and density in the thermodynamic phase equilibria ternary system (Li{sub 2}SO{sub 4} + K{sub 2}SO{sub 4} + H{sub 2}O) at 288.15 K and 0.1 MPa were investigated experimentally with the method of isothermal dissolution equilibrium. This system at 288.15 K consists of two invariant points, three univariant isothermal dissolution curves; and three crystallization regions. The salt Li{sub 2}SO{sub 4}·K{sub 2}SO{sub 4} belongs to the incongruent double salt, and no solid solution was found. Based on the Pitzer model and its extended Harvie–Weare (HW) model, the mixing ion-interaction parameters of θ{sub Li,K}, ψ{sub Li,K,SO4} at 288.15 K and the solubility equilibrium constants K{sub sp} of solid phases Li{sub 2}SO{sub 4}·H{sub 2}O and Li{sub 2}SO{sub 4}·K{sub 2}SO{sub 4}, which are not reported in the literature were acquired. A comparison between the calculated and experimental results at 288.15 K for the ternary system shows that the calculated solubilities obtained with the extended HW model agree well with experimental data.

Improvement programme of the UA2 detector

International Nuclear Information System (INIS)

Merkel, B.

1985-01-01

The author describes the process of modifying the present UA2 detector with the aim to match its performance to that of the improved Spp-barS Collider. The new design results from a number of choices dictated by the following considerations: the upgraded UA2 must be operational in 1987, as soon as the Collider resumes operation, in order to maximise its physics output during the period when TEV 1, with nearly three times as high a c.m. energy, has not yet taken over leadership; the upgraded UA2 must remain competitive on the major physics issues rather than diversify its detection capabilities; priority is given to the quality of the missing transverse energy measurement; and modifications to the vertex detector aim at ensuring that multivertex events can be reconstructed and at improving the detector performance in relation with electron identification

Temperature dependence of third order ion molecule reactions. The reaction H+3 + 2H2 = H+5 + H2

International Nuclear Information System (INIS)

Hiraoka, K.; Kebarle, P.

1975-01-01

The rate constants k 1 for Reaction (1): H + 3 +2H 2 = H + 5 +H 2 were measured in the temperature range 100--300 degreeK. The temperature dependence of k 1 has the form k 1 proportionalT - /subn/, where n=2.3. Pierce and Porter have reported a much stronger negative temperature dependence with n=4.6. The difference arises from a determination of k 1 at 300 degreeK obtained by Arifov and used by Porter. The present k 1 (300 degreeK) =9times10 -30 (cm 6 molecules -2 center-dotsec -1 ). This is more than an order of magnitude larger than the Arifov value. The temperature dependence of third body dependent association reactions like (1) is examined on the basis of the energy transfer theory and the recently proposed trimolecular complex transition state theory by Meot-Ner, Solomon, Field, and Gershinowitz. The temperature dependence of the rate constant for the reverse reaction (-1) is obtained from k 1 and the previously determined temperature dependence of the equilibria (1). k/sub -//sub 1/ gives a good straight line Arrhenius plot leading to k/sub -//sub 1/ =8.7times10 -6 exp(-8.4/RT) cm 3 molecules -1 center-dotsec -1 . The activation energy is in kcal/mole. The preexponential factor is much larger than the rate constant for Langevin collisions. This is typical for pyrolysis of ions involving second order activation

Dissociative ionization of H2 and D2 by electron impact near threshold

NARCIS (Netherlands)

Boesten, L.G.J.; Heideman, H.G.M.

We have studied the dissciative ionization of H2 and D2 by electron impact. It is found that in the vicinity of the 2Σ+g dissociation threshold of H+2 (18.08 eV) a significant fraction of the produced protons originates from the process e + H2 → H− + H+ + e (threshold at 17.34 eV). Similar results

Development activities on NIR large format MCT detectors for astrophysics and space science at CEA and SOFRADIR

Science.gov (United States)

Boulade, Olivier; Moreau, Vincent; Mulet, Patrick; Gravrand, Olivier; Cervera, Cyril; Zanatta, Jean-Paul; Castelein, Pierre; Guellec, Fabrice; Fièque, Bruno; Chorier, Philippe; Roumegoux, Julien

2016-07-01

CEA and SOFRADIR have been manufacturing and characterizing near infrared detectors in the frame of ESA's near infrared large format sensor array roadmap to develop a 2Kx2K large format low flux low noise device for space applications such as astrophysics. These detectors use HgCdTe as the absorbing material and p/n diode technology. The technological developments (photovoltaic technology, readout circuit, ...) are shared between CEA/LETI and SOFRADIR, both in Grenoble, while most of the performances are evaluated at CEA/IRFU in Saclay where a dedicated test facility has been developed, in particular to measure very low dark currents. The paper will present the current status of these developments at the end of ESA's NIRLFSA phase 2. The performances of the latest batch of devices meet or are very close to all the requirements (quantum efficiency, dark current, cross talk, readout noise, ...) even though a glow induced by the ROIC prevents the accurate measurement of the dark current. The current devices are fairly small, 640x512 15μm pixels, and the next phase of activity will target the development of a full size 2Kx2K detector. From the design and development, to the manufacturing and finally the testing, that type of detector requests a high level of mastering. An appropriate manufacturing and process chain compatible with such a size is needed at industrial level and results obtained with CEA technology coupled with Sofradir industrial experience and work on large dimension detector allow French actors to be confident to address this type of future missions.

Phase diagrams and physicochemical properties of Li+,K+(Rb+)//borate-H2O systems at 323 K

Science.gov (United States)

Feng, Shan; Yu, Xudong; Cheng, Xinglong; Zeng, Ying

2017-11-01

The phase and physicochemical properties diagrams of Li+,K+(Rb+)//borate-H2O systems at 323 K were constructed using the experimentally measured solubilities, densities, and refractive indices. The Schreinemakers' wet residue method and the X-ray diffraction were used for the determination of the compositions of solid phase. Results show that these two systems belong to the hydrate I type, with no solid solution or double salt formation. The borate phases formed in our experiments are RbB5O6(OH)4 · 2H2O, Li2B4O5(OH)4 · H2O, and K2B4O5(OH)4 · 2H2O. Comparison between the stable phase diagrams of the studied system at 288, 323, and 348 K show that in this temperature range, the crystallization form of salts do not changed. With the increase in temperature, the crystallization field of Li2B4O5(OH)4 · H2O salt at 348 K is obviously larger than that at 288 K. In the Li+,K+(Rb+)//borate-H2O systems, the densities and refractive indices of the solutions (at equilibrium) increase along with the mass fraction of K2B4O7 (Rb2B4O7), and reach the maximum values at invariant point E.

Human milk H2O2 content: does it benefit preterm infants?

Science.gov (United States)

Cieslak, Monika; Ferreira, Cristina H F; Shifrin, Yulia; Pan, Jingyi; Belik, Jaques

2018-03-01

BackgroundHuman milk has a high content of the antimicrobial compound hydrogen peroxide (H 2 O 2 ). As opposed to healthy full-term infants, preterm neonates are fed previously expressed and stored maternal milk. These practices may favor H 2 O 2 decomposition, thus limiting its potential benefit to preterm infants. The goal of this study was to evaluate the factors responsible for H 2 O 2 generation and degradation in breastmilk.MethodsHuman donors' and rats' milk, along with rat mammary tissue were evaluated. The role of oxytocin and xanthine oxidase on H 2 O 2 generation, its pH-dependent stability, as well as its degradation via lactoperoxidase and catalase was measured in milk.ResultsBreast tissue xanthine oxidase is responsible for the H 2 O 2 generation and its milk content is dependent on oxytocin stimulation. Stability of the human milk H 2 O 2 content is pH-dependent and greatest in the acidic range. Complete H 2 O 2 degradation occurs when human milk is maintained, longer than 10 min, at room temperature and this process is suppressed by lactoperoxidase and catalase inhibition.ConclusionFresh breastmilk H 2 O 2 content is labile and quickly degrades at room temperature. Further investigation on breastmilk handling techniques to preserve its H 2 O 2 content, when gavage-fed to preterm infants is warranted.

The effect of CO2, H2O and SO2 on the kinetics of NO reduction by CH4 over La2O3

International Nuclear Information System (INIS)

Toops, Todd J.; Walters, Arden B.; Vannice, M.A.

2002-01-01

The effect of CO 2 , H 2 O and SO 2 on the kinetics of NO reduction by CH 4 over unsupported La 2 O 3 has been examined between 773 and 973K in the presence of O 2 in the feed. La 2 O 3 can maintain a stable, high specific activity (mol/(sm 2 )) for NO reduction with high concentrations of CO 2 and H 2 O in the feed; however, either of these two products reversibly inhibits the activity by about one-half in the presence of excess O 2 . The catalyst is poisoned by SO 2 at these temperatures and an oxysulfate phase is formed, but partial regeneration can be achieved at 1023K. CO 2 in the feed causes the formation of lanthanum oxycarbonate, which reverts to La 2 O 3 when CO 2 is removed, but no bulk La oxyhydroxide is detected after quenching with H 2 O in the feed. The influence of CO 2 and H 2 O on kinetic behavior can be described by assuming they compete with reactants for adsorption on surface sites, including them in the site balance equation, and using the rate expression proposed previously for NO reduction by CH 4 in excess O 2 . With O 2 in the feed, integral conversions of CH 4 and O 2 frequently occurred due to the direct combustion of CH 4 by O 2 , although NO conversions remained differential; thus, an integral reactor model was chosen to analyze the data which utilized a recently determined rate equation for CH 4 combustion on La 2 O 3 in conjunction with a previously proposed model for NO reduction by CH 4 . The following rate expression described the rate of N 2 formation: N 2 T = ' NO P NO P CH 4 P O 2 0.5 / 1 + K NO P NO + K CH 4 P CH 4 + K O 2 0.5 P O 2 0.5 + K CO 2 P CO 2 + K H 2 O P H 2 O 2 . It gave a good fit to the experimental rate data for NO reduction, as well as providing enthalpies and entropies of adsorption obtained from the fitting parameters that demonstrated thermodynamic consistency and were similar to previous values. The heats of adsorption were altered somewhat when either CO 2 or H 2 O was added to the feed, and the following

A polysaccharide of Dendrobium officinale ameliorates H2O2-induced apoptosis in H9c2 cardiomyocytes via PI3K/AKT and MAPK pathways.

Science.gov (United States)

Zhang, Jing-Yi; Guo, Ying; Si, Jin-Ping; Sun, Xiao-Bo; Sun, Gui-Bo; Liu, Jing-Jing

2017-11-01

Dendrobium officinale is one valuable traditional Chinese medicine, which has skyscraping medicinal value. Polysaccharide is the main active ingredient in D. officinale; its antioxidant activity is a hot research topic nowadays. Oxidative stress plays an important role in the pathological progress of a variety of cardiovascular disease, as one of key factors of cardiomyocyte apoptosis. This research adopts a model of H 2 O 2 induction-H9c2 cardiomyocytes apoptosis, aiming to study the effect of Dendrobium officinale Polysaccharide (DOP-GY) for cardiomyocyte apoptosis caused by oxidative stress and its possible mechanism. Our results showed that pretreatment of DOP-GY (low dose: 6.25μg/mL, medium dose: 12.5μg/mL, high dose: 25μg/mL) followed by a 2h incubation with 200μM H 2 O 2 elevated the survival rate, cutted the LDH leakage, reduced lipid peroxidation damage, improved the activity of the endogenous antioxidant enzymes. In addition, the pretreatment of DOP-GY significantly inhibited the production of ROS, declined of the mitochondrial membrane potential, down-regulated pro-apoptosis protein and up-regulated anti-apoptosis protein. The protective effect was correlated with the PI3K/Akt and MAPK signal pathway. Collectively, these observations suggest that DOY-GY has the potential to exert cardioprotective effects against H 2 O 2 -induced H9c2 cardiomyocyte apoptosis. Copyright © 2017 Elsevier B.V. All rights reserved.

Drosophila KDM2 is a H3K4me3 demethylase regulating nucleolar organization

Directory of Open Access Journals (Sweden)

Birchler James A

2009-10-01

Full Text Available Abstract Background CG11033 (dKDM2 is the Drosophila homolog of the gene KDM2B. dKDM2 has been known to possess histone lysine demethylase activity towards H3K36me2 in cell lines and it regulates H2A ubiquitination. The human homolog of the gene has dual activity towards H3K36me2 as well as H3K4me3, and plays an important role in cellular senescence. Findings We have used transgenic flies bearing an RNAi construct for the dKDM2 gene. The knockdown of dKDM2 gene was performed by crossing UAS-RNAi-dKDM2 flies with actin-Gal4 flies. Western blots of acid extracted histones and immunofluoresence analysis of polytene chromosome showed the activity of the enzyme dKDM2 to be specific for H3K4me3 in adult flies. Immunofluoresence analysis of polytene chromosome also revealed the presence of multiple nucleoli in RNAi knockdown mutants of dKDM2 and decreased H3-acetylation marks associated with active transcription. Conclusion Our findings indicate that dKDM2 is a histone lysine demethylase with specificity for H3K4me3 and regulates nucleolar organization.

High resolution emission spectra of H2 and D2 near 80 nm

International Nuclear Information System (INIS)

Larzilliere, M.; Roncin, J.-Y.; Launay, F.

1980-01-01

A few lines have been observed in the far ultraviolet emission spectrum of molecular hydrogen and deuterium. They are assigned to transitions from levels of the 3pπD 1 PIsub(u)sup(-) state, lying above the dissociation limit into H(ls) + H(n=2), near 84.5 nm, and, for some of them, above the first ionization limit near 80.4 nm, the lower state being X 1 Σsub(g)sup(+) (v''=1). This is in fair agreement with measured predissociation and preionization yields. Accurate line position measurements lead to molecular constants in very good agreement with theoretical calculations

Structure of solid H2-D2 mixtures

International Nuclear Information System (INIS)

Krupskij, I.N.; Kovalenko, S.I.; Krajnyukova, N.V.

1978-01-01

The structure of vapor deposited H 2 -D 2 solid mixtures is investigated. The electron-diffraction examination has been carried out in the temperature range from 2.3K up to the sample sublimation temperature, taking place in case of H 2 at T approximately 5K and D 2 -at T approximately 7K. On the basis of the difractogramm obtained it is shown that in solid films of pure components a FCC structure with parameters asub(Hsub(2))=5.310+-0.01A and asub(Osub(2))=5.100+-0.005A is realized, the structure being metastable in the temperature range. The existence of non-limitted solubility in solid two-component condensates is stated. The decay absence at T approximately 5K, when molecula mobility is enough for the transition of metastable FCC structure into HCP, is in good agreement with the results of experimental and theoretical estimations, according to which the decay critical temperature should not exceed 4K. The existance of the continuous series of solutions at lower temperatures is explained by a small coefficient value of a volumetric and surface diffusion of molecula as well

2-(1H-Benzimidazol-2-yl-4,5,6,7-tetrahydro-2H-indazol-3-ol, a Benzimidazole Derivative, Inhibits T Cell Proliferation Involving H+/K+-ATPase Inhibition

Directory of Open Access Journals (Sweden)

Jin Liu

2014-10-01

Full Text Available In this study, a benzimidazole derivative named BMT-1 is revealed as a potential immunomodulatory agent. BMT-1 inhibits the activity of H+/K+-ATPases from anti-CD3/CD28 activated T cells. Furthermore, inhibition the H+/K+-ATPases by use of BMT-1 should lead to intracellular acidification, inhibiting T cell proliferation. To explore this possibility, the effect of BMT-1 on intracellular pH changes was examined by using BCECF as a pH-dependent fluorescent dye. Interestingly, increases in the pHi were observed in activated T cells, and T cells treated with BMT-1 showed a more acidic intracellular pH. Finally, BMT-1 targeted the H+/K+-ATPases and inhibited the proliferative response of anti-CD3/CD28-stimulated T cells. A cell cycle analysis indicated that BMT-1 arrested the cell cycle progression of activated T cells from the G1 to the S phase without affecting CD25 expression or interleukin-2 (IL-2 production; treating IL-2-dependent PBMCs with BMT-1 also led to the inhibition of cell proliferation. Taken together, these findings demonstrate that BMT-1 inhibits the proliferation of T cells by interfering with H+/K+-ATPases and down-regulating intracellular pHi. This molecule may be an interesting lead compound for the development of new immunomodulatory agents.

Synthesis and characterization of polymer eight-coordinate (enH 2)[Y III(pdta)(H 2O)] 2·10H 2O as well as the interaction of [Y III(pdta)(H 2O)] 22- with BSA

Science.gov (United States)

Liu, Bin; Wang, Jun; Wang, Xin; Liu, Bing-Mi; He, Ling-Ling; Xu, Shu-Kun

2010-12-01

The eight-coordinate (enH 2)[Y III(pdta)(H 2O)] 2·10H 2O (en = ethylenediamine and H 4pdta = 1,3-propylenediamine- N, N, N', N'-tetraacetic acid) was synthesized, meanwhile its molecular and crystal structures were determined by single-crystal X-ray diffraction technology. The interaction between [Y III(pdta)(H 2O)] 22- and bovine serum albumin (BSA) was investigated by UV-vis and fluorescence spectra. The results indicate that [Y III(pdta)(H 2O)] 22- quenched effectively the intrinsic fluorescence of BSA via a static quenching process with the binding constant ( Ka) of the order of 10 4. Meanwhile, the binding and damaging sites to BSA molecules were also estimated by synchronous fluorescence. Results indicate that the hydrophobic environments around Trp and Tyr residues were all slightly changed. The thermodynamic parameters (Δ G = -25.20 kJ mol -1, Δ H = -26.57 kJ mol -1 and Δ S = -4.58 J mol -1 K -1) showed that the reaction was spontaneous and exothermic. What is more, both Δ H and Δ S were negative values indicated that hydrogen bond and Van der Waals forces were the predominant intermolecular forces between [Y III(pdta)(H 2O)] 22- and BSA.

The vibration-rotation-tunneling levels of N2-H2O and N2-D2O

Science.gov (United States)

Wang, Xiao-Gang; Carrington, Tucker

2015-07-01

In this paper, we report vibration-rotation-tunneling levels of the van der Waals clusters N2-H2O and N2-D2O computed from an ab initio potential energy surface. The only dynamical approximation is that the monomers are rigid. We use a symmetry adapted Lanczos algorithm and an uncoupled product basis set. The pattern of the cluster's levels is complicated by splittings caused by H-H exchange tunneling (larger splitting) and N-N exchange tunneling (smaller splitting). An interesting result that emerges from our calculation is that whereas in N2-H2O, the symmetric H-H tunnelling state is below the anti-symmetric H-H tunnelling state for both K = 0 and K = 1, the order is reversed in N2-D2O for K = 1. The only experimental splitting measurements are the D-D exchange tunneling splittings reported by Zhu et al. [J. Chem. Phys. 139, 214309 (2013)] for N2-D2O in the v2 = 1 region of D2O. Due to the inverted order of the split levels, they measure the sum of the K = 0 and K = 1 tunneling splittings, which is in excellent agreement with our calculated result. Other splittings we predict, in particular those of N2-H2O, may guide future experiments.

T2KLAr: a liquid Argon TPC for the T2K neutrino experiment

International Nuclear Information System (INIS)

Meregaglia, Anselmo

2006-01-01

A 2km LAr detector would be an important asset for the T2K experiment, especially because of its role in reducing the systematics. It would also be an important milestone for this technique paving the way for future applications. Its main features are explained in this talk

T2KLAr: a liquid Argon TPC for the T2K neutrino experiment

Science.gov (United States)

Meregaglia, Anselmo

2006-05-01

A 2km LAr detector would be an important asset for the T2K experiment, especially because of its role in reducing the systematics. It would also be an important milestone for this technique paving the way for future applications. Its main features are explained in this talk.

Theoretical study of [Li(H2O)n]+ and [K(H2O)n]+ (n = 1-4) complexes

International Nuclear Information System (INIS)

Wojcik, M.J.; Mains, G.J.; Devlin, J.P.

1995-01-01

The geometries, successive binding energies, vibrational frequencies, and infrared intensities are calculated for the [Li(H 2 O) n ] + and [K(H 2 O) n ] + (n = 1-4) complexes. The basis sets used are 6-31G * and LANL1DZ (Los Alamos ECP+DZ) at the SCF and MP2 levels. There is an agreement for calculated structures and frequencies between the MP2/6-31G * and MP2/LANL1DZ basis sets, which indicates that the latter can be used for calculations of water complexes with heavier ions. Our results are in a reasonable agreement with available experimental data and facilitate experimental study of these complexes. 19 refs., 4 figs., 6 tabs

Reaction kinetics of H{sub 2}, O{sub 2}, and H{sub 2}O with rare earths (Y, La, Ce, Pr, Nd, Gd, Tb, Dy, and Er) at 298 K

Energy Technology Data Exchange (ETDEWEB)

Enomoto, M.; Ohata, Y. [Course of Applied Science, Graduate School of Engineering, Tokai University, 4-1-1 Kita-Kaname, Hiratsuka, Kanagawa 259-1292 (Japan); Uchida, H., E-mail: huchida@keyaki.cc.u-tokai.ac.jp [Course of Applied Science, Graduate School of Engineering, Tokai University, 4-1-1 Kita-Kaname, Hiratsuka, Kanagawa 259-1292 (Japan)

2013-12-15

Highlights: ► H{sub 2} molecules react with a clean surface of each RE sample at the highest reactivity even at 298 K. ► The H{sub 2} reactivity becomes reduced by the formation of dihydrides of each RE sample. ► The RE with a clean surface adsorb O{sub 2} more than one monolayer of O{sub 2} even at 298 K. ► The quantitative reactivity of the H atoms dissociated from H{sub 2}O was calculated. -- Abstract: High reactivity of rare earths (RE) with H{sub 2}, O{sub 2} and H{sub 2}O is well known even at room temperature. The formation of stable surface oxides/hydroxides on the surface is the one of serious problems in the production and use of materials containing RE. We have investigated the quantitative reactivities of H{sub 2}, O{sub 2}, and H{sub 2}O with the surface of Y, La, Ce, Pr, Nd, Gd, Tb, Dy, and Er under ultra high vacuum condition. The H{sub 2}, O{sub 2} and H{sub 2}O gases exhibited the highest reactivity on the clean surface of the RE at 298 K. This means that all gas molecules impinging the surface dissociate and chemisorbed. The O atoms dissociated from O{sub 2} adsorb to for oxides layers of the metals. The H atoms dissociated from H{sub 2} diffuse into the metals to form hydrides which were found to decrease the H{sub 2} reactivity. The H atoms dissociated form H{sub 2}O diffuse into the metals or form hydroxides of the metals. With increasing coverage of each gas molecules, the reactivity of each gas was decreased by several orders of magnitude.

Interstellar matter near the Pleiades. III. A search for H2 2.4-micron vibration-rotation emission

International Nuclear Information System (INIS)

White, R.E.

1988-01-01

Results are reported from a search for 2.4-micron v = 1-0 H2 emission near five stars in the Pleiades, performed using a cooled InSb photometer and a 10-arcsec entrance aperture on the 2.3-m telescope at Wyoming IR Observatory. The calibration and data-reduction procedures are described, and the results are presented in a table. No emission is detected, and upper limits in the range 0.000026-0.000072 erg/sec sq cm sr are obtained, corresponding to limiting column densities of (1.3-3.7) x 10 to the 15th/sq cm and H2 densities of 400-1100/cu cm (assuming fluorescence and dissociation of the gas as it passes the stars). 16 references

NEAR-INFRARED IMAGING OF THE STAR-FORMING REGIONS SH2-157 AND SH2-152

International Nuclear Information System (INIS)

Chen Yafeng; Yang Ji; Zeng Qin; Yao Yongqiang; Sato, Shuji

2009-01-01

Near-infrared JHK' and H 2 v = 1-0 S (1) imaging observations of the star-forming regions Sh2-157 and Sh2-152 are presented. The data reveal a cluster of young stars associated with H 2 line emission in each region. Additionally, many IR point sources are found in the dense core of each molecular cloud. Most of these sources exhibit infrared color excesses typical of T Tauri stars, Herbig Ae/Be stars, and protostars. Several display the characteristics of massive stars. We calculate histograms of the K'-magnitude and [H - K'] color for all sources, as well as two-color and color-magnitude diagrams. The stellar populations inside and outside the clusters are similar, suggesting that these systems are rather evolved. Shock-driven H 2 emission knots are also detected, which may be related to evident subclusters in an earlier evolutionary stage.

Densities, viscosities, and refractive indexes for {C2H5CO2(CH2)2CH3+C6H13OH+C6H6} at T=308.15 K

International Nuclear Information System (INIS)

Casas, Herminio; Garcia-Garabal, Sandra; Segade, Luisa; Cabeza, Oscar.; Franjo, Carlos; Jimenez, Eulogio

2003-01-01

In this work we present densities, kinematic viscosities, and refractive indexes of the ternary system {C 2 H 5 CO 2 (CH 2 ) 2 CH 3 +C 6 H 13 OH+C 6 H 6 } and the corresponding binary mixtures {C 2 H 5 CO 2 (CH 2 ) 2 CH 3 +C 6 H 6 }, {C 2 H 5 CO 2 (CH 2 ) 2 CH 3 +C 6 H 13 OH}, and {C 6 H 13 OH+C 6 H 6 }. All data have been measured at T=308.15 K and atmospheric pressure over the whole composition range. The excess molar volumes, dynamic viscosity deviations, and changes of the refractive index on mixing were calculated from experimental measurements. The results for binary mixtures were fitted to a polynomial relationship to estimate the coefficients and standard deviations. The Cibulka equation has been used to correlate the experimental values of ternary mixtures. Also, the experimental values obtained for the ternary mixture were used to test the empirical methods of Kohler, Jacob and Fitzner, Colinet, Tsao and Smith, Toop, Scatchard et al., and Hillert. These methods predict excess properties of the ternary mixtures from those of the involved binary mixtures. The results obtained for dynamic viscosities of the binary mixtures were used to test the semi-empirical relations of Grunberg-Nissan, McAllister, Auslaender, and Teja-Rice. Finally, the experimental refractive indexes were compared with the predicted results for the Lorentz-Lorenz, Gladstone-Dale, Wiener, Heller, and Arago-Biot equations. In all cases, we give the standard deviation between the experimental data and that calculated with the above named relations

Measurement of F_2^ccbar and F_2^bbbar at High Q^2 using the H1 Vertex Detector at HERA

CERN Document Server

Aktas, A.; Anthonis, T.; Aplin, S.; Asmone, A.; Babaev, A.; Backovic, S.; Bahr, J.; Baghdasaryan, A.; Baranov, P.; Barrelet, E.; Bartel, W.; Baudrand, S.; Baumgartner, S.; Becker, J.; Beckingham, M.; Behnke, O.; Behrendt, O.; Belousov, A.; Berger, Ch.; Berger, N.; Berndt, T.; Bizot, J.C.; Bohme, J.; Boenig, M.-O.; Boudry, V.; Bracinik, J.; Brandt, G.; Brisson, V.; Broker, H.-B.; Brown, D.P.; Bruncko, D.; Busser, F.W.; Bunyatyan, A.; Buschhorn, G.; Bystritskaya, L.; Campbell, A.J.; Caron, S.; Cassol-Brunner, F.; Cerny, K.; Chekelian, V.; Contreras, J.G.; Coppens, Y.R.; Coughlan, J.A.; Cox, B.E.; Cozzika, G.; Cvach, J.; Dainton, J.B.; Dau, W.D.; Daum, K.; Delcourt, B.; Demirchyan, R.; De Roeck, A.; Desch, K.; De Wolf, E.A.; Diaconu, C.; Dingfelder, J.; Dodonov, V.; Dubak, A.; Duprel, C.; Eckerlin, Guenter; Efremenko, V.; Egli, S.; Eichler, R.; Eisele, F.; Ellerbrock, M.; Elsen, E.; Erdmann, W.; Essenov, S.; Faulkner, P.J.W.; Favart, L.; Fedotov, A.; Felst, R.; Ferencei, J.; Finke, L.; Fleischer, M.; Fleischmann, P.; Fleming, Y.H.; Flucke, G.; Flugge, G.; Fomenko, A.; Foresti, I.; Formanek, J.; Franke, G.; Frising, G.; Frisson, T.; Gabathuler, E.; Gabathuler, K.; Garutti, E.; Garvey, J.; Gayler, J.; Gerhards, R.; Gerlich, C.; Ghazaryan, Samvel; Ginzburgskaya, S.; Glazov, A.; Glushkov, I.; Goerlich, L.; Goettlich, M.; Gogitidze, N.; Gorbounov, S.; Goyon, C.; Grab, C.; Grassler, H.; Greenshaw, T.; Gregori, M.; Grindhammer, Guenter; Gwilliam, C.; Haidt, D.; Hajduk, L.; Haller, J.; Hansson, M.; Heinzelmann, G.; Henderson, R.C.W.; Henschel, H.; Henshaw, O.; Herrera, G.; Herynek, I.; Heuer, R.-D.; Hildebrandt, M.; Hiller, K.H.; Hoting, P.; Hoffmann, D.; Horisberger, R.; Hovhannisyan, A.; Ibbotson, M.; Ismail, M.; Jacquet, M.; Janauschek, L.; Janssen, X.; Jemanov, V.; Jonsson, L.; Johnson, D.P.; Jung, H.; Kant, D.; Kapichine, M.; Karlsson, M.; Katzy, J.; Keller, N.; Kenyon, I.R.; Kiesling, Christian M.; Klein, M.; Kleinwort, C.; Klimkovich, T.; Kluge, T.; Knies, G.; Knutsson, A.; Korbel, V.; Kostka, P.; Koutouev, R.; Kropivnitskaya, A.; Kruger, K.; Kuckens, J.; Landon, M.P.J.; Lange, W.; Lastovicka, T.; Laycock, P.; Lebedev, A.; Leiner, B.; Lemrani, R.; Lendermann, V.; Levonian, S.; Lindfeld, L.; Lipka, K.; List, B.; Lobodzinska, E.; Loktionova, N.; Lopez-Fernandez, R.; Lubimov, V.; Lueders, H.; Luke, D.; Lux, T.; Lytkin, L.; Makankine, A.; Malden, N.; Malinovski, E.; Mangano, S.; Marage, P.; Marks, J.; Marshall, R.; Martisikova, M.; Martyn, H.-U.; Maxeld, S.J.; Meer, D.; Mehta, A.; Meier, K.; Meyer, A.B.; Meyer, H.; Meyer, J.; Mikocki, S.; Milcewicz-Mika, I.; Milstead, D.; Mohamed, A.; Moreau, F.; Morozov, A.; Morris, J.V.; Mozer, Matthias Ulrich; Muller, K.; Murin, P.; Nagovizin, V.; Nankov, K.; Naroska, B.; Naumann, J.; Naumann, Th.; Newman, Paul R.; Niebuhr, C.; Nikiforov, A.; Nikitin, D.; Nowak, G.; Nozicka, M.; Oganezov, R.; Olivier, B.; Olsson, J.E.; Ozerov, D.; Pascaud, C.; Patel, G.D.; Peez, M.; Perez, E.; Perez-Astudillo, D.; Perieanu, A.; Petrukhin, A.; Pitzl, D.; Placakyte, R.; Poschl, R.; Portheault, B.; Povh, B.; Prideaux, P.; Raicevic, N.; Reimer, P.; Rimmer, A.; Risler, C.; Rizvi, E.; Robmann, P.; Roland, B.; Roosen, R.; Rostovtsev, A.; Rurikova, Z.; Rusakov, S.; Salvaire, F.; Sankey, D.P.C.; Sauvan, E.; Schatzel, S.; Scheins, J.; Schilling, F.-P.; Schmidt, S.; Schmitt, S.; Schmitz, C.; Schneider, M.; Schoeffel, L.; Schoning, A.; Schroder, V.; Schultz-Coulon, H.-C.; Schwanenberger, C.; Sedlak, K.; Sefkow, F.; Sheviakov, I.; Shtarkov, L.N.; Sirois, Y.; Sloan, T.; Smirnov, P.; Soloviev, Y.; South, D.; Spaskov, V.; Specka, Arnd E.; Stella, B.; Stiewe, J.; Strauch, I.; Straumann, U.; Tchoulakov, V.; Thompson, Graham; Thompson, P.D.; Tomasz, F.; Traynor, D.; Truoel, Peter; Tsipolitis, G.; Tsurin, I.; Turnau, J.; Tzamariudaki, E.; Uraev, A.; Urban, Marcel; Usik, A.; Utkin, D.; Valkar, S.; Valkarova, A.; Vallee, C.; Van Mechelen, P.; Van Remortel, N.; Vargas Trevino, A.; Vazdik, Y.; Veelken, C.; Vest, A.; Vinokurova, S.; Volchinski, V.; Vujicic, B.; Wacker, K.; Wagner, J.; Weber, G.; Weber, R.; Wegener, D.; Werner, C.; Werner, N.; Wessels, M.; Wessling, B.; Wigmore, C.; Winter, G.-G.; Wissing, Ch.; Woehrling, E.-E.; Wolf, R.; Wunsch, E.; Xella, S.; Yan, W.; Yeganov, V.; Zacek, J.; Zalesak, J.; Zhang, Z.; Zhelezov, A.; Zhokin, A.; Zimmermann, J.; Zohrabyan, H.; Zomer, F.

2004-01-01

Measurements are presented of inclusive charm and beauty cross sections in e^+p collisions at HERA for values of photon virtuality Q^2 > 150 GeV^2 and of inelasticity 0.1 < y < 0.7. The charm and beauty fractions are determined using a method based on the impact parameter, in the transverse plane, of tracks to the primary vertex, as measured by the H1 vertex detector. The data are divided into four regions in Q^2 and Bjorken x, and values for the structure functions F_2^{c\\bar{c}} and F_2^{b\\bar{b}} are obtained. The results are found to be compatible with the predictions of perturbative quantum chromodynamics.

Rate constant and thermochemistry for K + O2 + N2 = KO2 + N2

DEFF Research Database (Denmark)

Sorvajärvi, Tapio; Viljanen, Jan; Toivonen, Juha

2015-01-01

in the form of double exponential decays of [K], which yielded both kR1 and the equilibrium constant for KO2 formation. kR1 can be summarized as 1.07 × 10-30(T/1000 K)-0.733 cm6 molecule-2 s-1. Combination with literature values leads to a recommended kR1 of 5.5 × 10-26T-1.55 exp(-10/T) cm6 molecule-2 s-1...... over 250-1320 K, with an error limit of a factor of 1.5. A vant Hoff analysis constrained to fit the computed ΔS298 yields a K-O2 bond dissociation enthalpy of 184.2 ± 4.0 kJ mol-1 at 298 K and ΔfH298(KO2) = -95.2 ± 4.1 kJ mol-1. The corresponding D0 is 181.5 ± 4.0 kJ mol-1. This value compares well...

The Rate Constant for the Reaction H + C2H5 at T = 295 - 150K

Science.gov (United States)

Pimentel, Andre S.; Payne, Walter A.; Nesbitt, Fred L.; Cody, Regina J.; Stief, Louis J.

2004-01-01

The reaction between the hydrogen atom and the ethyl (C2H3) radical is predicted by photochemical modeling to be the most important loss process for C2H5 radicals in the atmospheres of Jupiter and Saturn. This reaction is also one of the major sources for the methyl radicals in these atmospheres. These two simplest hydrocarbon radicals are the initial species for the synthesis of larger hydrocarbons. Previous measurements of the rate constant for the H + C2H5 reaction varied by a factor of five at room temperature, and some studies showed a dependence upon temperature while others showed no such dependence. In addition, the previous studies were at higher temperatures and generally higher pressures than that needed for use in planetary atmospheric models. The rate constant for the reaction H + C2H5 has been measured directly at T = 150, 202 and 295 K and at P = 1.0 Torr He for all temperatures and additionally at P = 0.5 and 2.0 Torr He at T = 202 K. The measurements were performed in a discharge - fast flow system. The decay of the C2H5 radical in the presence of excess hydrogen was monitored by low-energy electron impact mass spectrometry under pseudo-first order conditions. H atoms and C2H5 radicals were generated rapidly and simultaneously by the reaction of fluorine atoms with H2 and C2H6, respectively. The total rate constant was found to be temperature and pressure independent. The measured total rate constant at each temperature are: k(sub 1)(295K) = (1.02+/-0.24)x10(exp -10), k(sub 1)(202K) = (1.02+/-0.22)x10(exp -10) and k(sub 1)(150K) = (0.93+/-0.21)x10(exp -10), all in units of cu cm/molecule/s. The total rate constant derived from all the combined measurements is k(sub 1) = (l.03+/-0.17)x10(exp -10) cu cm/molecule/s. At room temperature our results are about a factor of two higher than the recommended rate constant and a factor of three lower than the most recently published study.

Neutron detection using Dy2O3 activation detectors

International Nuclear Information System (INIS)

Gomaa, M.A.; Mohamed, E.J.

1979-01-01

The aim of the present study is to examine the usefulness of Dy 2 O 3 not only as thermal neutron activation detector but also as a fast neutron detector. For thermal neutrons, the half life of 165 Dy is measured to be (141 +- 6) min, its response to thermal neutrons is (2.18 +- 0.01) cpm/ncm -2 s -1 for a 250 mg Dy 2 O 3 pellet. For fast neutrons the Dy 2 O 3 detector is placed within a 20 cm polyethylene sphere and its response is found to be (2.2 +- 0.1) cpm/ncm -2 s -1 for 4 MeV neutrons and (2.10 +- 0.04) cpm/ncm -2 s -1 for 14 MeV neutrons. For neutron dosimetry, its response is found to be (16.7 +- 0.4) cpm per mrem h -1 . (author)

Isotopic equilibrium constants of the deuterium exchange between HDO and H2S, H2Se and H2Te

International Nuclear Information System (INIS)

Marx, D.

1959-11-01

We have determined experimentally the equilibrium constant K of each of the following isotope exchanges: SH 2 + OHD ↔ SHD + OH 2 ; SeH 2 + OHD ↔ SeHD + OH 2 ; TeH 2 + OHD ↔ TeHD + OH 2 . In gaseous phase, statistical thermodynamics leads to the expression: K (Z OHD x Z RH 2 )/(Z OH 2 x Z RHD ) x e W/T (R being the elements S, Se or Te). Z, the partition functions, have been calculated and, through our experimental results, the constant W has been determined. Having obtained W, the equilibrium constant K has been calculated for a series of temperatures. (author) [fr

Ferromagnetic Coupling between Copper(II) Centers through the Diamagnetic Zinc(II) Ion: Crystal Structure and Magnetic Properties of [Cu(2)Zn(Hdmg)(2)(dmg)(2)(H(2)O)].0.5H(2)dmg.H(2)O (H(2)dmg = Dimethylglyoxime).

Science.gov (United States)

Ruiz, Rafael; Julve, Miguel; Faus, Juan; Lloret, Francesc; Muñoz, M. Carmen; Journaux, Yves; Bois, Claudette

1997-07-30

A new heterotrinuclear complex of formula [Cu(2)Zn(Hdmg)(2)(dmg)(2)(H(2)O)].0.5H(2)dmg.H(2)O (C(18)H(34)Cu(2)N(9)O(11)Zn, 1) (H(2)dmg = dimethylglyoxime) has been synthesized and its crystal structure determined by single-crystal X-ray diffraction. It crystallizes in the triclinic system, space group P&onemacr;, with a = 11.414(1) Å, b = 11.992(3) Å, c =12.567(10) Å, alpha = 91.27(6) degrees, beta = 111.46(2) degrees, gamma = 112.24(2) degrees, and Z = 2. The structure consists of a chain of neutral [Cu(2)Zn(Hdmg)(2)(dmg)(2)(H(2)O)] trinuclear units and noncoordinated H(2)dmg and water molecules. The configuration around the zinc atom is distorted trigonal bipyramidal with four oximate oxygens from two [Cu(Hdmg)(dmg)](-) fragments (each one acting as a bidentate ligand through its deprotonated oximate oxygens in cis positions) occupying one axial and the three equatorial positions and an additional oximate oxygen from a symmetry-related [Cu(Hdmg)(dmg)](-) fragment filling the remaining axial position. The environment around Cu(1) and Cu(2) is distorted square pyramidal with four oximate nitrogen atoms building the equatorial plane. An oxygen atom [O(9)] from a water molecule and an oximate oxygen from a symmetry-related [Cu(Hdmg)(dmg)](-) fragment occupy the apical position of the square pyramids around Cu(1) and Cu(2), respectively. The trinuclear units are repeated through inversion centers standing at the middle of the Zn(1).Zn(1)(i) and Cu(2).Cu(2)(ii) vectors leading to a chain which runs parallel to the diagonal of the ac-plane. The Cu(1).Cu(2), Zn(1).Zn(1)(i), and Cu(2).Cu(2)(ii) separations are 5.506(2), 3.390(2), and 3.930(2) Å, respectively. 1 exhibits a characteristic ferromagnetic behavior with a continuous increase of the chi(M)T product as the temperature is lowered from 300 to 2.0 K. The field dependence of the magnetization at 2.0 K is consistent with a low-lying quintet state. The only efficient exchange pathways responsible for the overall

Characterization of Low-mass K2 planet hosts using Near-Infrared Spectroscopy

Science.gov (United States)

Rodríguez-Martínez, Romy; Ballard, Sarah

2017-01-01

The raw number of discovered exoplanets now exceeds several thousand, but we must understand the stars if we aim to understand their planets in detail. Of particular interest are M dwarf stars, which are often favored for exoplanet study because (1) they host small planets in greatest abundance, (2) they make up about 70% of stars in our galaxy, and (3) the planets that orbit them that are comparatively easier to find and study than planets around larger stars. Our work aims to characterize the infrared spectra of 50 M dwarfs with new and unstudied transiting planets discovered by NASA’s K2 Mission. We employ empirical relations from the literature with magnesium, aluminum and sodium absorption lines in H and K band to determine the temperatures, radii and luminosities. In addition, we measure the deformation of the spectra in K band by water (another empirical metric for M dwarfs) which, in tandem with absorption features, is linked to [Fe/H] metallicity. We have found from a preliminary sample of 36 stars, that the temperatures range from 2,900 to 4,100 K, with radii between 0.2 R⊙ to 0.6R⊙ and log(L/L⊙) values from -3.4 to -0.5. The determination of all these properties improves our understanding of the planet’s properties, such as its size, mass, and surface temperature, and provides clues about the formation of the star and its planets.

Human organic cation transporter 2 (hOCT2): Inhibitor studies using S2-hOCT2 cells

International Nuclear Information System (INIS)

Chiba, Shoetsu; Ikawa, Toru; Takeshita, Hiroshi; Kanno, Sanae; Nagai, Tomonori; Takada, Meri; Mukai, Toshiji; Wempe, Michael F.

2013-01-01

Highly expressed in kidney and located on the basolateral membrane, human organic cation transporter 2 (hOCT2) can transport various compounds (i.e. drugs and toxins) into the proximal tubular cell. Using cultured proximal tubule cells stably expressing hOCT2 (i.e. S2-hOCT2 cells), we sought to probe different compound classes (e.g. analgesics, anti-depressants, anti-psychotics, disinfectant, herbicides, insecticides, local anesthetic, muscarinic acetylcholine receptor antagonist, sedatives, steroid hormone, stimulants and toxins) for their ability to inhibit 14 C-TEA uptake, a prototypical OCT2 substrate. Aconitine, amitriptyline, atropine, chlorpyrifos, diazepam, fenitrothion, haloperidol, lidocaine, malathion, mianserin, nicotine and triazolam significantly inhibited 14 C-TEA uptake; IC 50 values were 59.2, 2.4, 2.0, 20.7, 32.3, 13.2, 32.5, 104.6, 71.1, 17.7, 52.8 and 65.5 μM, respectively. In addition, aconitine, amitriptyline, atropine, chlorpyrifos, fenitrothion, haloperidol, lidocaine, and nicotine displayed competitive inhibition with K i values of 145.6, 2.5, 2.4, 24.8, 16.9, 51.6, 86.8 and 57.7 μM, respectively. These in vitro data support the notion that compounds pertaining to a wide variety of different drug classes have the potential to decrease renal clearance of drugs transported via hOCT2. Consequently, these data warrant additional studies to probe hOCT2 and its role to influence drug pharmacokinetics

Anti-H-Y responses of H-2b mutant mice.

Science.gov (United States)

Simpson, E; Gordon, R D; Chandler, P R; Bailey, D

1978-10-01

Two strains of H-2b mutant mice, H-2ba and H-2bf, in which the mutational event took place at H-2K, make anti-H-Y cytotoxic T cell responses which are H-2-restricted, Db-associated and indistinguishable in target cell specificity from those of H-2b mice. Thus, alteration of the H-2K molecule affects neither the Ir gene controlling the response, nor the associative antigen. On the other hand, one H-2Db mutant strain, H-2bo, although it makes a good anti-H-Y cytotoxic response, shows target cell specificity restricted to its own Dbo antigen(s), and neither H-2b, H-2ba or H-2bf anti-H-Y cytotoxic cells kill H-2bo male target cells. Thus, the alteration of the H-2Db molecule does not affect the Ir gene of H-2b mice, but it does alter the H-2Db-associative antigen.

A Sequential Method to Prepare Polymorphs and Solvatomorphs of [Fe(1,3-bpp)2 ](ClO4 )2 ⋅nH2 O (n=0, 1, 2) with Varying Spin-Crossover Behaviour.

Science.gov (United States)

Bartual-Murgui, Carlos; Codina, Carlota; Roubeau, Olivier; Aromí, Guillem

2016-08-26

Two polymorphs of the spin crossover (SCO) compound [Fe(1,3-bpp)2 ](ClO4 )2 (1 and 2; 1,3-bpp=2-(pyrazol-1-yl)-6-(pyrazol-3-yl)pyridine) were prepared using a novel, stepwise procedure. Crystals of 1 deposit from dry solvents, while 2 is obtained from a solid-state procedure, by sequentially removing lattice H2 O molecules from the solvatomorph [Fe(1,3-bpp)2 ](ClO4 )2 ⋅2 H2 O (2⋅2 H2 O), using single-crystal-to-single-crystal (SCSC) transformations. Hydrate 2⋅2 H2 O is obtained through the same reaction as 1, now with 2.5 % of water added. Compounds 2 and 2⋅2 H2 O are unstable in the atmosphere and absorb or lose one equivalent of water, respectively, to both yield the stable solvatomorph [Fe(1,3-bpp)2 ](ClO4 )2 ⋅H2 O (2⋅H2 O), also following SCSC processes. The four derivatives have been characterised by single-crystal X-ray diffraction (SCXRD). Furthermore, the homogeneity of the various compounds as well as their SCSC interconversions have been confirmed by powder X-ray diffraction (PXRD). Polymorphs 1 and 2 exhibit abrupt SCO behaviour near room temperature with T1/2↑ =279/316 K and T1/2↓ =276/314 K (near 40 K of shift) and different cooperativity. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Observation of ESR spin flip satellite lines of trapped hydrogen atoms in solid H2 at 4.2 K

International Nuclear Information System (INIS)

Miyazaki, Tetsuo; Iwata, Nobuchika; Fueki, Kenji; Hase, Hirotomo

1990-01-01

ESR spectra of H atoms, produced in γ-irradiated solid H 2 , were studied at 4.2 K. Two main lines of the ESR spectra of H atoms that are separated by about 500 G accompanied two weak satellite lines. Both satellite lines and main lines decrease with the same decay rate. In the D 2 -H 2 mixtures, the satellite-line intensity depends upon the number of matrix protons. The spacing of the satellites from the main lines is equal to that of the NMR proton resonance frequency. It was concluded that the satellite lines were not ascribable to paired atoms but to spin flip lines due to an interaction of H atoms with matrix protons. The analysis of the spin flip lines and the main lines suggests that H atoms in solid H 2 are trapped in the substitutional site

Relaxation of photogenerated carriers under He, H sub 2 , CO sub 2 and O sub 2 on ZnO

CERN Document Server

Han, C S; Jun, J

1998-01-01

The relaxation process of photogenerated carriers was investigated using conductivity measurement on ZnO under He,H sub 2 ,CO sub 2 and O sub 2. The process was well explained with the rate constant of reaction or recombination of hole and electron, k sub h and k sub e (k sub h >k sub e), respectively. Generally, k sub h increased with the pressure of the gases. The slope of k sub h with respect to the pressure increased in the order of H sub 2<=He2 , while k sub h of O sub 2 was sensitive to the history of the sample. The relaxation process on ZnO which was exposed to oxygen at 298 K and 573 K was observed during the illumination time. From the result, it was suggested that the rate constant of photo generated excess carriers was affected by the surface barrier of the semiconductor.

Neutrino Oscillation Experiments with J-PARC: T2K, T2K-II and Hyper-Kamiokande

CERN Multimedia

CERN. Geneva

2016-01-01

The T2K experiment started the operation in 2010, and advances neutrino physics with the discovery of electron neutrino appearance in the muon neutrino beam and precision measurements of neutrino oscillation parameters. In 2016, the measurements of anti-neutrino oscillation directly constrain CP violation in neutrino oscillation. In this colloquium, we introduce many physics results from T2K including the most recent one of the CP violation. By utilizing the J-PARC neutrino beam, the upgrade of the T2K experiment (naming T2K-II) is planned and Hyper-Kamiokande is proposed to explore neutrino physics further. In T2K-II, the beam power of J-PARC will be upgraded to 1.3 MW around 2020. Hyper-Kamiokande is the larger Water Cherenkov detector of 520 k...

Physiological Expression of AMPKγ2RG Mutation Causes Wolff-Parkinson-White Syndrome and Induces Kidney Injury in Mice.

Science.gov (United States)

Yang, Xiaodong; Mudgett, John; Bou-About, Ghina; Champy, Marie-France; Jacobs, Hugues; Monassier, Laurent; Pavlovic, Guillaume; Sorg, Tania; Herault, Yann; Petit-Demoulière, Benoit; Lu, Ku; Feng, Wen; Wang, Hongwu; Ma, Li-Jun; Askew, Roger; Erion, Mark D; Kelley, David E; Myers, Robert W; Li, Cai; Guan, Hong-Ping

2016-11-04

Mutations of the AMP-activated kinase gamma 2 subunit (AMPKγ2), N488I (AMPKγ2 NI ) and R531G (AMPKγ2 RG ), are associated with Wolff-Parkinson-White (WPW) syndrome, a cardiac disorder characterized by ventricular pre-excitation in humans. Cardiac-specific transgenic overexpression of human AMPKγ2 NI or AMPKγ2 RG leads to constitutive AMPK activation and the WPW phenotype in mice. However, overexpression of these mutant proteins also caused profound, non-physiological increase in cardiac glycogen, which might abnormally alter the true phenotype. To investigate whether physiological levels of AMPKγ2 NI or AMPKγ2 RG mutation cause WPW syndrome and metabolic changes in other organs, we generated two knock-in mouse lines on the C57BL/6N background harboring mutations of human AMPKγ2 NI and AMPKγ2 RG , respectively. Similar to the reported phenotypes of mice overexpressing AMPKγ2 NI or AMPKγ2 RG in the heart, both lines developed WPW syndrome and cardiac hypertrophy; however, these effects were independent of cardiac glycogen accumulation. Compared with AMPKγ2 WT mice, AMPKγ2 NI and AMPKγ2 RG mice exhibited reduced body weight, fat mass, and liver steatosis when fed with a high fat diet (HFD). Surprisingly, AMPKγ2 RG but not AMPKγ2 NI mice fed with an HFD exhibited severe kidney injury characterized by glycogen accumulation, inflammation, apoptosis, cyst formation, and impaired renal function. These results demonstrate that expression of AMPKγ2 NI and AMPKγ2 RG mutations at physiological levels can induce beneficial metabolic effects but that this is accompanied by WPW syndrome. Our data also reveal an unexpected effect of AMPKγ2 RG in the kidney, linking lifelong constitutive activation of AMPK to a potential risk for kidney dysfunction in the context of an HFD. © 2016 by The American Society for Biochemistry and Molecular Biology, Inc.

Physiological Expression of AMPKγ2RG Mutation Causes Wolff-Parkinson-White Syndrome and Induces Kidney Injury in Mice*

Science.gov (United States)

Yang, Xiaodong; Mudgett, John; Bou-About, Ghina; Champy, Marie-France; Jacobs, Hugues; Monassier, Laurent; Pavlovic, Guillaume; Sorg, Tania; Herault, Yann; Petit-Demoulière, Benoit; Lu, Ku; Feng, Wen; Wang, Hongwu; Ma, Li-Jun; Askew, Roger; Erion, Mark D.; Kelley, David E.; Myers, Robert W.; Li, Cai

2016-01-01

Mutations of the AMP-activated kinase gamma 2 subunit (AMPKγ2), N488I (AMPKγ2NI) and R531G (AMPKγ2RG), are associated with Wolff-Parkinson-White (WPW) syndrome, a cardiac disorder characterized by ventricular pre-excitation in humans. Cardiac-specific transgenic overexpression of human AMPKγ2NI or AMPKγ2RG leads to constitutive AMPK activation and the WPW phenotype in mice. However, overexpression of these mutant proteins also caused profound, non-physiological increase in cardiac glycogen, which might abnormally alter the true phenotype. To investigate whether physiological levels of AMPKγ2NI or AMPKγ2RG mutation cause WPW syndrome and metabolic changes in other organs, we generated two knock-in mouse lines on the C57BL/6N background harboring mutations of human AMPKγ2NI and AMPKγ2RG, respectively. Similar to the reported phenotypes of mice overexpressing AMPKγ2NI or AMPKγ2RG in the heart, both lines developed WPW syndrome and cardiac hypertrophy; however, these effects were independent of cardiac glycogen accumulation. Compared with AMPKγ2WT mice, AMPKγ2NI and AMPKγ2RG mice exhibited reduced body weight, fat mass, and liver steatosis when fed with a high fat diet (HFD). Surprisingly, AMPKγ2RG but not AMPKγ2NI mice fed with an HFD exhibited severe kidney injury characterized by glycogen accumulation, inflammation, apoptosis, cyst formation, and impaired renal function. These results demonstrate that expression of AMPKγ2NI and AMPKγ2RG mutations at physiological levels can induce beneficial metabolic effects but that this is accompanied by WPW syndrome. Our data also reveal an unexpected effect of AMPKγ2RG in the kidney, linking lifelong constitutive activation of AMPK to a potential risk for kidney dysfunction in the context of an HFD. PMID:27621313

A homologous series of homoleptic zinc bis(1,4-di-tert-butyl-1,4-diaza-1,3-butadiene) complexes: Kx[Zn(t-BuNCHCHN-t-Bu)2], Zn(t-BuNCHCHN-t-Bu)2, and [Zn(t-BuNCHCHN-t-Bu)2](OTf)x)(X=1,2)

NARCIS (Netherlands)

Koten, G. van; Rijnberg, E.; Richter, B.; Thiele, K.-H.; Boersma, J.; Veldman, N.; Spek, A.L.

1998-01-01

A homologous series of mono- and dicationic, neutral, and mono- and dianionic zinc diazabutadiene complexes, Kx[Zn(t-BuNCHCHN-t-Bu)2], Zn(t-BuNCHCHN-t-Bu)2, and [Zn(t-BuNCHCHN-t-Bu)2](OTf)x (x = 1, 2), have been prepared and isolated in pure form. The crystal structures of the mono- and dicationic

Characterization of a real time H2O2 monitor for use in studies on H2O2 production by antibodies and cells.

Science.gov (United States)

Sharma, Harish A; Balcavage, Walter X; Waite, Lee R; Johnson, Mary T; Nindl, Gabi

2003-01-01

It was recently shown that antibodies catalyze a reaction between water and ultraviolet light (UV) creating singlet oxygen and ultimately H2O2. Although the in vivo relevance of these antibody reactions is unclear, it is interesting that among a wide variety of non-antibody proteins tested, the T cell receptor is the only protein with similar capabilities. In clinical settings UV is believed to exert therapeutic effects by eliminating inflammatory epidermal T cells and we hypothesized that UV-triggered H2O2 production is involved in this process. To test the hypothesis we developed tools to study production of H2O2 by T cell receptors with the long-term goal of understanding, and improving, UV phototherapy. Here, we report the development of an inexpensive, real time H2O2 monitoring system having broad applicability. The detector is a Clark oxygen electrode (Pt, Ag/AgCl) modified to detect UV-driven H2O2 production. Modifications include painting the electrode black to minimize UV effects on the Ag/AgCl electrode and the use of hydrophilic, large pore Gelnots electrode membranes. Electrode current was converted to voltage and then amplified and recorded using a digital multimeter coupled to a PC. A reaction vessel with a quartz window was developed to maintain constant temperature while permitting UV irradiation of the samples. The sensitivity and specificity of the system and its use in cell-free and cell-based assays will be presented. In a cellfree system, production of H2O2 by CD3 antibodies was confirmed using our real time H2O2 monitoring method. Additionally we report the finding that splenocytes and Jurkat T cells also produce H2O2 when exposed to UV light.

Efficacy of a Recombinant Turkey Herpesvirus H5 Vaccine Against Challenge With H5N1 Clades 1.1.2 and 2.3.2.1 Highly Pathogenic Avian Influenza Viruses in Domestic Ducks (Anas platyrhynchos domesticus).

Science.gov (United States)

Pantin-Jackwood, Mary J; Kapczynski, Darrell R; DeJesus, Eric; Costa-Hurtado, Mar; Dauphin, Gwenaelle; Tripodi, Astrid; Dunn, John R; Swayne, David E

2016-03-01

Domestic ducks are the second most abundant poultry species in many Asian countries and have played a critical role in the epizootiology of H5N1 highly pathogenic avian influenza (HPAI).In this study, the protective efficacy of a live recombinant vector vaccine based on a turkey herpesvirus (HVT) expressing the H5 gene from a clade 2.2 H5N1 HPAI strain (A/Swan/Hungary/4999/ 2006) (rHVT-H5/2.2), given at 3 days of age, was examined in Pekin ducks (Anas platyrhynchos domesticus). The vaccine was given alone or in combination with an inactivated H5N1 clade 2.3.2.1 reverse genetic (rgGD/2.3.2.1) vaccine given at 16 days of age, either as a single vaccination or in a prime-boost regime. At 30 days of age, ducks were challenged with one of two H5N1 HPAI viruses: A/duck/Vietnam/NCVD-2721/2013 (clade 1.1.2) or A/duck/Vietnam/NCVD-1584/2012 (clade 2.3.2.1.C). These viruses produced 100% mortality in less than 5 days in nonvaccinated control ducks. Ducks vaccinated with the rgGD/2.3.2.1 vaccine, with or without the rHVT-H5/2.2 vaccine, were 90%-100% protected against mortality after challenge with either of the two H5N1 HPAI viruses. The rHVT-H5/2.2 vaccine alone, however, conferred only 30% protection against mortality after challenge with either H5N1 HPAI virus; the surviving ducks from these groups shed higher amount of virus and for longer than the single-vaccinated rgGD/2.3.2.1 group. Despite low protection, ducks vaccinated with the rHVT-H5/2.2 vaccine and challenged with the clade 1.1.2 Vietnam virus had a longer mean death time than nonvaccinated controls (P = 0.02). A booster effect was found on reduction of virus shedding when using both vaccines, with lower oropharyngeal viral titers at 4 days after challenge with either HPAI virus (P study demonstrates the suboptimal protection with the rHVT-H5/2.2 vaccine given alone in Pekin ducks against H5N1 HPAI viruses and only a minor additive effect on virus shedding reduction when used with an inactivated vaccine in a

Thermodynamic studies of (RbF + RbCl + H2O) and (CsF + CsCl + H2O) ternary systems from potentiometric measurements at T = 298.2 K

International Nuclear Information System (INIS)

Huang, Xiaoting; Li, Shu’ni; Zhai, Quanguo; Jiang, Yucheng; Hu, Mancheng

2016-01-01

Graphical abstract: Thermodynamic properties, such as mean activity coefficients, osmotic coefficients and excess Gibbs free energies, of the RbF + RbCl + H 2 O and CsF + CsCl + H 2 O ternary systems were determined from potentiometric measurement at 298.2 K. The Pitzer model and the Harned rule were used to fit the experimental data. - Highlights: • Thermodynamic properties of RbF + RbCl + H 2 O and CsF + CsCl + H 2 O ternary systems were determined. • The Pitzer model and the Harned rule were used to correlate the experimental data. • The mean activity coefficients, osmotic coefficients, and the excess Gibbs free energy were also obtained. - Abstract: Thermodynamic properties of (RbF + RbCl + H 2 O) and (CsF + CsCl + H 2 O) systems were determined by the potentiometric method for different ionic strength fractions y B of RbCl/CsCl at 298.2 K. The Pitzer model and the Harned rule were used to fit the experimental values. The Pitzer mixing parameters and the Harned coefficients were evaluated. In addition, the mean ionic activity coefficients of RbF/CsF and RbCl/CsCl, the osmotic coefficients, and the excess Gibbs energies of the systems studied were calculated.

Highly precise (liquid + liquid) equilibrium and heat capacity measurements near the critical point for [Bmim][BF4] + 1H, 1H, 2H, 2H perfluoroctanol

International Nuclear Information System (INIS)

Pérez-Sánchez, G.; Troncoso, J.; Losada-Pérez, P.; Méndez-Castro, P.; Romaní, L.

2013-01-01

Highlights: • Highly precise liquid–liquid curves for [Bmim][BF 4 ] + perfluoroctanol are reported. • Critical behavior of heat capacity for the same system was also characterized. • In contrast to previous results, no coulombic/solvophobic crossover for coexistence curve diameter was found. • The system criticality shows characteristics both solvophobic and coulombic. -- Abstract: Liquid + liquid equilibrium of the system [Bmim][BF 4 ] + 1H, 1H, 2H, 2H perfluoroctanol using a highly precise methodology based on refractive index measurements was experimentally determined. In addition, isobaric heat capacity near the critical point was obtained. The performance of the new refractive index set-up was successfully checked against the coexistence curve of the system dimethyl carbonate + decane, since highly accurate data are available in the literature. The choice of [Bmim][BF 4 ] + 1H, 1H, 2H, 2H perfluoroctanol was motivated by a previous experimental work, whose results suggest that this system could present characteristics of both solvophobic and coulombic behavior, which are the two categories to which an ionic system can belong. Although this was previously observed for other ionic systems, this mixture presented a very striking feature: the diameter of the coexistence curve seemed to change its criticality in the studied temperature range, from solvophobic far away to coulombic close to the critical point. The results of this work reveal that, in fact, [Bmim][BF 4 ] + 1H, 1H, 2H, 2H perfluoroctanol presents characteristics of both solvophobic and coulombic criticality, but no evidence of the observed crossover over the experimental temperature range has been found

Neutron scattering studies of K3H(SO4)2 and K3D(SO4)2: the particle-in-a-box model for the quantum phase transition.

Science.gov (United States)

Fillaux, François; Cousson, Alain

2012-08-21

In the crystal of K(3)H(SO(4))(2) or K(3)D(SO(4))(2), dimers SO(4)···H···SO(4) or SO(4)···D···SO(4) are linked by strong centrosymmetric hydrogen or deuterium bonds whose O···O length is ≈2.50 Å. We address two open questions. (i) Are H or D sites split or not? (ii) Is there any structural counterpart to the phase transition observed for K(3)D(SO(4))(2) at T(c) ≈ 85.5 K, which does not exist for K(3)H(SO(4))(2)? Neutron diffraction by single-crystals at cryogenic or room temperature reveals no structural transition and no resolvable splitting of H or D sites. However, the width of the probability densities suggest unresolved splitting of the wavefunctions suggesting rigid entities H(L1/2)-H(R1/2) or D(L1/2)-D(R1/2) whose separation lengths are l(H) ≈ 0.16 Å or l(D) ≈ 0.25 Å. The vibrational eigenstates for the center of mass of H(L1/2)-H(R1/2) revealed by inelastic neutron scattering are amenable to a square-well and we suppose the same potential holds for D(L1/2)-D(R1/2). In order to explain dielectric and calorimetric measurements of mixed crystals K(3)D((1-ρ))H(ρ)(SO(4))(2) (0 ≤ ρ ≤ 1), we replace the classical notion of order-disorder by the quantum notion of discernible (e.g., D(L1/2)-D(R1/2)) or indiscernible (e.g., H(L1/2)-H(R1/2)) components depending on the separation length of the split wavefunction. The discernible-indiscernible isostructural transition at finite temperatures is induced by a thermal pure quantum state or at 0 K by ρ.

A Highly Sensitive Porous Silicon (P-Si)-Based Human Kallikrein 2 (hK2) Immunoassay Platform toward Accurate Diagnosis of Prostate Cancer.

Science.gov (United States)

Lee, Sang Wook; Hosokawa, Kazuo; Kim, Soyoun; Jeong, Ok Chan; Lilja, Hans; Laurell, Thomas; Maeda, Mizuo

2015-05-22

Levels of total human kallikrein 2 (hK2), a protein involved the pathology of prostate cancer (PCa), could be used as a biomarker to aid in the diagnosis of this disease. In this study, we report on a porous silicon antibody immunoassay platform for the detection of serum levels of total hK2. The surface of porous silicon has a 3-dimensional macro- and nanoporous structure, which offers a large binding capacity for capturing probe molecules. The tailored pore size of the porous silicon also allows efficient immobilization of antibodies by surface adsorption, and does not require chemical immobilization. Monoclonal hK2 capture antibody (6B7) was dispensed onto P-Si chip using a piezoelectric dispenser. In total 13 × 13 arrays (169 spots) were spotted on the chip with its single spot volume of 300 pL. For an optimization of capture antibody condition, we firstly performed an immunoassay of the P-Si microarray under a titration series of hK2 in pure buffer (PBS) at three different antibody densities (75, 100 and 145 µg/mL). The best performance of the microarray platform was seen at 100 µg/mL of the capture antibody concentration (LOD was 100 fg/mL). The platform then was subsequently evaluated for a titration series of serum-spiked hK2 samples. The developed platform utilizes only 15 µL of serum per test and the total assay time is about 3 h, including immobilization of the capture antibody. The detection limit of the hK2 assay was 100 fg/mL in PBS buffer and 1 pg/mL in serum with a dynamic range of 106 (10(-4) to 10(2) ng/mL).

The Amelioration of N-Acetyl-p-Benzoquinone Imine Toxicity by Ginsenoside Rg3: The Role of Nrf2-Mediated Detoxification and Mrp1/Mrp3 Transports

Directory of Open Access Journals (Sweden)

Sang Il Gum

2013-01-01

Full Text Available Previously, we found that Korean red ginseng suppressed acetaminophen (APAP-induced hepatotoxicity via alteration of its metabolic profile involving GSTA2 induction and that ginsenoside Rg3 was a major component of this gene induction. In the present study, therefore, we assessed the protective effect of Rg3 against N-acetyl-p-benzoquinone imine (NAPQI, a toxic metabolic intermediate of APAP. Excess NAPQI resulted in GSH depletion with increases in the ALT and AST activities in H4IIE cells. Rg3 pretreatment reversed GSH depletion by NAPQI. Rg3 resulted in increased mRNA levels of the catalytic and modulatory subunit of glutamate cysteine ligase (GCL, the rate-limiting steps in GSH synthesis and subsequently increased GSH content. Rg3 increased levels of nuclear Nrf2, an essential transcriptional factor of these genes. The knockdown or knockout of the Nrf2 gene abrogated the inductions of mRNA and protein by Rg3. Abolishment of the reversal of GSH depletion by Rg3 against NAPQI was observed in Nrf2-deficient cells. Rg3 induced multidrug resistance-associated protein (Mrp 1 and Mrp3 mRNA levels, but not in Nrf2-deficient cells. Taken together, these results demonstrate that Rg3 is efficacious in protecting hepatocytes against NAPQI insult, due to GSH repletion and coordinated gene regulations of GSH synthesis and Mrp family genes by Nrf2.

The nanosecond generator RG-1 with near-rectangular pulse

International Nuclear Information System (INIS)

Bulan, V.V.; Grabovskij, E.V.; Gribov, A.N.; Luzhnov, V.G.

1996-01-01

The 300 kV, 17 Ohm generator RG-1, which can deliver near-rectangular pulses with a pulse duration of 80 ns FWHM, is described. The polarity of the output pulse can be changed by a simple switch. The fast capacities of the Marx generator are used instead of the pulse forming line. Multi-spark gas switches were developed to decrease the inductance of the discharged circuit. The generator is supplied by a built-in high voltage source and its operation is controlled by a minicomputer. It is used the power supply-line 220 V. The RG-1 can be used in different modes of operation: gas discharge, particle beam formation, etc. (author). 4 figs., 3 refs

The nanosecond generator RG-1 with near-rectangular pulse

Energy Technology Data Exchange (ETDEWEB)

Bulan, V V; Grabovskij, E V; Gribov, A N; Luzhnov, V G [TRINITI, Troitsk (Russian Federation)

1997-12-31

The 300 kV, 17 Ohm generator RG-1, which can deliver near-rectangular pulses with a pulse duration of 80 ns FWHM, is described. The polarity of the output pulse can be changed by a simple switch. The fast capacities of the Marx generator are used instead of the pulse forming line. Multi-spark gas switches were developed to decrease the inductance of the discharged circuit. The generator is supplied by a built-in high voltage source and its operation is controlled by a minicomputer. It is used the power supply-line 220 V. The RG-1 can be used in different modes of operation: gas discharge, particle beam formation, etc. (author). 4 figs., 3 refs.

Monte Carlo analysis of Pu-H2O and UO2-PuO2-H2O critical assemblies with ENDF/B-IV data

International Nuclear Information System (INIS)

Hardy, J. Jr.; Ullo, J.J.

1981-04-01

A set of critical experiments, comprising thirteen homogeneous Pu-H 2 O assemblies and twelve UO 2 -PuO 2 lattices, was analyzed with ENDF/B-IV data and the RCPO1 Monte Carlo program, which modeled the experiments explicitly. Some major data sensitivities were also evaluated. For the Pu-H 2 O assemblies, calculated K/sub eff/ averaged 1.011. The large (2.7%) scatter of K/sub eff/ values for these assemblies was attributed mostly to uncertainties in physical specifications since no clear trends of K/sub eff/ were evident and data sensitivities were insignificant. The UO 2 -PuO 2 lattices showed just one trend of K/sub eff/, which indicated an overprediction of U238 capture consistent with that observed for uranium-H 2 O experiments. There was however a approx. 1% discrepancy in calculated K/sub eff/ between the two sets of UO 2 -PuO 2 lattices studied

Van der Waals bond in dimers: H2Ne, H2Ar, H2Kr

International Nuclear Information System (INIS)

Waaijer, M.

1981-01-01

The H 2 -inert gas dimers H 2 X, and particularly H 2 Ne, H 2 Ar and H 2 Kr, form the subject of this thesis and are loosely bound van der Waals complexes, which is reflected in the low number of bound states and the small anisotropic interaction. The H 2 X dimers studied are formed in a supersonic nozzle expansion, in which the internal energy is converted into the macroscopic flow energy, establishing an internal temperature drop to 3 K, which favours dimer formation. Because of this cooling the H 2 X dimers relax to the lowest rotational states. The hyperfine transitions have been measured using magnetic beam resonance and yield information about the isotropic as well as the anisotropic intermolecular potential in the range between the classical turning points and in the adjacent part of the repulsive branch. The sensitivity of the method is very high and slight changes in the intermolecular potential cause significant effects. The analysis of the measured hyperfine transitions incorporates all interacting states of the molecule, bound as well as unbound (continuum) states. For H 2 Ne, which is the best studied H 2 -inert gas system from the experimental point of view, the author succeeded in establishing an intermolecular potential, that provides a solid ground for comparison with future ab initio calculations. (Auth.)

K2-99

DEFF Research Database (Denmark)

Smith, A. M. S.; Gandolfi, D.; Barragan, O.

2017-01-01

We report the discovery from K2 of a transiting planet in an 18.25-d, eccentric (0.19 +/- 0.04) orbit around K2-99, an 11th magnitude subgiant in Virgo. We confirm the planetary nature of the companion with radial velocities, and determine that the star is a metal-rich ([ Fe/H] = 0.20 +/- 0...

Thermal Reactions of H2O2 on Icy Satellites and Small Bodies: Descent with Modification?

Science.gov (United States)

Hudson, Reggie L.; Loeffler, Mark J.

2012-01-01

Magnetospheric radiation drives surface and near-surface chemistry on Europa, but below a few meters Europa's chemistry is hidden from direct observation . As an example, surface radiation chemistry converts H2O and SO2 into H2O2 and (SO4)(sup 2-), respectively, and these species will be transported downward for possible thermally-driven reactions. However, while the infrared spectra and radiation chemistry of H2O2-containing ices are well documented, this molecule's thermally-induced solid-phase chemistry has seldom been studied. Here we report new results on thermal reactions in H2O + H2O2 + SO2 ices at 50 - 130 K. As an example of our results, we find that warming H2O + H2O2 + SO2 ices promotes SO2 oxidation to (SO4)(sup 2-). These results have implications for the survival of H2O2 as it descends, with modification, towards a subsurface ocean on Europa. We suspect that such redox chemistry may explain some of the observations related to the presence and distribution of H2O2 across Europa's surface as well as the lack of H2O2 on Ganymede and Callisto.

The LUCID-2 Detector

CERN Document Server

Soluk, Richard; The ATLAS collaboration

2017-01-01

The LUCID-2 detector is the main online and offline luminosity provider of the ATLAS experiment. It provides over 100 different luminosity measurements from different algorithms for each of the 2808 LHC bunches. LUCID was entirely redesigned in preparation for LHC Run 2: both the detector and the electronics were upgraded in order to cope with the challenging conditions expected at the LHC center of mass energy of 13 TeV with only 25 ns bunch-spacing. While LUCID-1 used gas as a Cherenkov medium, the LUCID-2 detector is in a new unique way using the quartz windows of small photomultipliers as the Cherenkov medium. The main challenge for a luminometer is to keep the efficiency constant during years of data-taking. LUCID-2 is using an innovative calibration system based on radioactive 207 Bi sources deposited on the quartz window of the readout photomultipliers. This makes it possible to accurately monitor and control the gain of the photomultipliers so that the detector efficiency can be kept stable at a perce...

The LUCID-2 Detector

CERN Document Server

Pinfold, James; The ATLAS collaboration

2017-01-01

The LUCID-2 detector is the main online and offline luminosity provider of the ATLAS experiment. It provides over 100 different luminosity measurements from different algorithms for each of the 2808/3546 filled/total LHC bunches. LUCID was entirely redesigned in preparation for LHC Run 2: both the detector and the electronics were upgraded in order to cope with the challenging conditions expected at the LHC center of mass energy of 13 TeV with only 25 ns bunch-spacing. While LUCID-1 used gas as a Cherenkov medium, the LUCID-2 detector is in a new unique way using the quartz windows of small photomultipliers as the Cherenkov medium. The main challenge for a luminometer is to keep the efficiency constant during years of data-taking. LUCID-2 is using an innovative calibration system based on radioactive 207 Bi sources deposited on the quartz window of the readout photomultipliers. This makes it possible to accurately monitor and control the gain of the photomultipliers so that the detector efficiency can be kept...

The LUCID-2 detector

CERN Document Server

Sbarra, Carla; The ATLAS collaboration

2018-01-01

The LUCID-2 detector is the main online and offline luminosity provider of the ATLAS experiment. It provides over 100 different luminosity measurements from different algorithms for each of the 2808 LHC bunches. LUCID was entirely redesigned in preparation for LHC Run 2: both the detector and the electronics were upgraded in order to cope with the challenging conditions expected at the LHC center of mass energy of 13 TeV with only 25 ns bunch-spacing. While LUCID-1 used gas as a Cherenkov medium, the LUCID-2 detector is in a new unique way using the quartz windows of small photomultipliers as the Cherenkov medium. The main challenge for a luminometer is to keep the efficiency constant during years of data-taking. LUCID-2 is using an innovative calibration system based on radioactive 207 Bi sources deposited on the quartz window of the readout photomultipliers. This makes it possible to accurately monitor and control the gain of the photomultipliers so that the detector efficiency can be kept stable at a perce...

Synthesis and structure of [(NH2)2CSSC(NH2)2]2[OsBr6]Br2 . 3H2O

International Nuclear Information System (INIS)

Rudnitskaya, O. V.; Kultyshkina, E. K.; Stash, A. I.; Glukhova, A. A.; Venskovskii, N. U.

2008-01-01

The complex [(NH 2 ) 2 CSSC(NH 2 ) 2 ] 2 [OsBr 6 ]Br 2 . 3H 2 O is synthesized by the reaction of K 2 OsBr 6 with thiocarbamide in concentrated HBr and characterized using electronic absorption and IR absorption spectroscopy. Its crystal structure is determined by X-ray diffraction. The crystals are orthorhombic, a = 11.730(2) A, b = 14.052(3) A, c = 16.994(3) A, space group Cmcm, and Z = 4. The [OsBr 6 ] 2- anionic complex has an octahedral structure. The Os-Br distances fall in the range 2.483-2.490 A. The α,α'-dithiobisformamidinium cation is a product of the oxidation of thiocarbamide. The S-S and C-S distances are 2.016 and 1.784 A, respectively. The H 2 O molecules, Br - ions, and NH 2 groups of the cation are linked by hydrogen bonds.

Energy-sensitive imaging detector applied to the dissociative recombination of D2H+

International Nuclear Information System (INIS)

Buhr, H.; Schwalm, D.; Mendes, M. B.; Novotny, O.; Berg, M. H.; Bing, D.; Krantz, C.; Orlov, D. A.; Sorg, T.; Stuetzel, J.; Varju, J.; Wolf, A.; Heber, O.; Rappaport, M. L.; Zajfman, D.

2010-01-01

We report on an energy-sensitive imaging detector for studying the fragmentation of polyatomic molecules in the dissociative recombination of fast molecular ions with electrons. The system is based on a large area (10x10 cm 2 ) position-sensitive, double-sided Si-strip detector with 128 horizontal and 128 vertical strips, whose pulse height information is read out individually. The setup allows us to uniquely identify fragment masses and is thus capable of measuring branching ratios between different fragmentation channels, kinetic energy releases, and breakup geometries as a function of the relative ion-electron energy. The properties of the detection system, which has been installed at the Test Storage Ring (TSR) facility of the Max-Planck Institute for Nuclear Physics in Heidelberg, is illustrated by an investigation of the dissociative recombination of the deuterated triatomic hydrogen cation D 2 H + . A huge isotope effect is observed when comparing the relative branching ratio between the D 2 + H and the HD + D channel; the ratio 2B(D 2 + H)/B(HD + D), which is measured to be 1.27±0.05 at relative electron-ion energies around 0 eV, is found to increase to 3.7±0.5 at ∼5 eV.

Energy-sensitive imaging detector applied to the dissociative recombination of D2H+

Science.gov (United States)

Buhr, H.; Mendes, M. B.; Novotný, O.; Schwalm, D.; Berg, M. H.; Bing, D.; Heber, O.; Krantz, C.; Orlov, D. A.; Rappaport, M. L.; Sorg, T.; Stützel, J.; Varju, J.; Wolf, A.; Zajfman, D.

2010-06-01

We report on an energy-sensitive imaging detector for studying the fragmentation of polyatomic molecules in the dissociative recombination of fast molecular ions with electrons. The system is based on a large area (10×10 cm2) position-sensitive, double-sided Si-strip detector with 128 horizontal and 128 vertical strips, whose pulse height information is read out individually. The setup allows us to uniquely identify fragment masses and is thus capable of measuring branching ratios between different fragmentation channels, kinetic energy releases, and breakup geometries as a function of the relative ion-electron energy. The properties of the detection system, which has been installed at the Test Storage Ring (TSR) facility of the Max-Planck Institute for Nuclear Physics in Heidelberg, is illustrated by an investigation of the dissociative recombination of the deuterated triatomic hydrogen cation D2H+. A huge isotope effect is observed when comparing the relative branching ratio between the D2 + H and the HD + D channel; the ratio 2B(D2 + H)/B(HD + D), which is measured to be 1.27±0.05 at relative electron-ion energies around 0 eV, is found to increase to 3.7±0.5 at ~5 eV.

Magnetic measurements and neutron diffraction study of the layered hybrid compounds Mn(C8H4O4)(H2O)2 and Mn2(OH)2(C8H4O4)

International Nuclear Information System (INIS)

Sibille, Romain; Mesbah, Adel; Mazet, Thomas; Malaman, Bernard; Capelli, Silvia; François, Michel

2012-01-01

Mn(C 8 H 4 O 4 )(H 2 O) 2 and Mn 2 (OH) 2 (C 8 H 4 O 4 ) layered organic–inorganic compounds based on manganese(II) and terephthalate molecules (C 8 H 4 O 4 2− ) have been studied by DC and AC magnetic measurements and powder neutron diffraction. The dihydrated compound behaves as a 3D antiferromagnet below 6.5 K. The temperature dependence of its χT product is typical of a 2D Heisenberg system and allows determining the in-plane exchange constant J≈−7.4 K through the carboxylate bridges. The magnetic structure confirms the in-plane nearest neighbor antiferromagnetic interactions and the 3D ordering. The hydroxide based compound also orders as a 3D antiferromagnet with a higher Néel temperature (38.5 K). Its magnetic structure is described from two antiferromagnetically coupled ferromagnetic sublattices, in relation with the two independent metallic sites. The isothermal magnetization data at 2 K are consistent with the antiferromagnetic ground-state of these compounds. However, in both cases, a slope change points to field-induced modification of the magnetic structure. - Graphical abstract: The macroscopic magnetic properties and magnetic structures of two metal-organic frameworks based on manganese (II) and terephthalate molecules are presented. Highlights: ► Magnetic study of Mn(C 8 H 4 O 4 )(H 2 O) 2 and Mn 2 (OH) 2 (C 8 H 4 O 4 ). ► Two compounds with common features (interlayer linker/distance, S=5/2 spin). ► Magnetic measurements quantitatively analyzed to deduce exchange constants. ► Magnetic structures determined from neutron powder diffraction experiments.

Tetrahedral silsesquioxane-C2H2Ti complex for hydrogen storage

Science.gov (United States)

Konda, Ravinder; Tavhare, Priyanka; Ingale, Nilesh; Chaudhari, Ajay

2018-04-01

The interaction of molecular hydrogen with tetrahedral silsesquioxane (T4)-C2H2Ti complex has been studied using Density Functional Theory with M06-2X functional and MP2 method with 6-311++G** basis set. T4-C2H2Ti complex can absorb maximum five hydrogen molecules with the gravimetric hydrogen storage capacity of 3.4 wt %. Adsorption energy calculations show that H2 adsorption on T4-C2H2Ti complex is favorable at room temperature by both the methods. We have studied the effect of temperature and pressure on Gibbs free energy corrected adsorption energies. Molecular dynamics simulations for H2 adsorbed T4-C2H2Ti complex have also been performed at 300K and show that loosely bonded H2 molecule flies away within 1fs. Various interaction energies within the complex are studied. Stability of a complex is predicted by means of a gap between Highest Occupied Molecular Orbital (HUMO) and Lowest Unoccupied Molecular Orbital (LUMO). The H2 desorption temperature for T4-C2H2Ti complex is calculated with Van't Hoff equation and it is found to be 229K.

Physical properties and the Peierls instability of Li0.82[Pt(S2C2(CN)2)2] · 2H2O

DEFF Research Database (Denmark)

Ahmad, M. M.; Turner, D. J.; Underhill, A. E.

1984-01-01

The infrared reflectivity, the temperature-dependent conductivity, and thermopower of the one-dimensional conductor Li0.82[Pt(S2C2(CN)2)2] · 2H2O, LiPt(mnt), is presented. It undergoes a simple Peierls transition at Tc=215 K, which is not influenced by correlations or by cation ordering. The meta...

Thermally activated 3D to 2D structural transformation of [Ni2(en)2(H2O)6(pyr)]·4H2O flexible coordination polymer

International Nuclear Information System (INIS)

Begović, Nebojša N.; Blagojević, Vladimir A.; Ostojić, Sanja B.; Radulović, Aleksandra M.; Poleti, Dejan; Minić, Dragica M.

2015-01-01

Thermally activated 3D to 2D structural transformation of the binuclear [Ni 2 (en) 2 (H 2 O) 6 (pyr)]·4H 2 O complex was investigated using a combination of theoretical and experimental methods. Step-wise thermal degradation (dehydration followed by release of ethylene diamine) results in two layered flexible coordination polymer structures. Dehydration process around 365 K results in a conjugated 2D structure with weak interlayer connectivity. It was shown to be a reversible 3D to 2D framework transformation by a guest molecule, and rehydration of the dehydration product occurs at room temperature in saturated water vapor. Rehydrated complex exhibits lower dehydration temperature, due to decreased average crystalline size, with higher surface area resulting in easier release and diffusion of water during dehydration. Thermal degradation of dehydration around 570 K, results in loss of ethylene diamine, producing a related 2D layered polymer structure, without interconnectivity between individual polymer layers. - Highlights: • Reversible 3D to 2D framework topochemical transformation on dehydration around 365 K. • Resulting polymer exhibits 2D layered structure with weak interlayer connectivity. • Dehydration is fully reversible in saturated water vapor at room temperature. • Further degradation around 570 K yields 2D polymer without interlayer connectivity. • 2D polymer exhibits conjugated electronic system

Excitation processes in slow K+--He, Ne, Ar, H2, N2 and Na+--He collisions

International Nuclear Information System (INIS)

Kikiani, B.I.; Gochitashvili, M.R.; Kvizhinadze, R.V.; Ankudinov, V.A.

1984-01-01

Quasimolecular features of excitation processes in K + --He, Ne, Ar, H 2 , N 2 and Na + --He collisions were investigated by measuring the cross sections for the emission of the resonance lines of potassium (lambda = 766.5 and 769.9 nm), sodium (lambda = 589 and 589.6 nm), and helium (lambda = 584 nm) atoms at ion energies in the range 0.5--10 keV. In Na + --He collisions, the resonance-line excitation functions obtained for sodium and helium atoms exhibit oscillations that are in antiphase and are due to phase interference between the quasimolecular states of the system of colliding particles. Experimental data on K + --Ar collisions are interpreted in terms of schematic correlation diagrams for molecular orbitals. The excitation mechanisms for K + --N 2 and K + --Ar have beenfound to be similar, and this leads to the conclusion that the quasimolecular model used for the ion-atom case is also valid for the ion-molecule case. It is shown that the excitation of the 4p-state of the potassium atom in the K + --Ar case is due to a Landau-Zener type of interaction in the region of the quasicrossing of (KAr) + terms. Analysis of the excitation of this state in K + --N 2 collisions also shows that the capture of an electron into the excited 4p-state of the potassium atom is due to a nonadiabatic transition in the region of quasicrossing of energy terms of the same symmetry

N-(2-Methylphenyl-1,2-benzoselenazol-3(2H-one

Directory of Open Access Journals (Sweden)

Xu Zhu

2013-10-01

Full Text Available In the title Ebselen [systematic name: (2-phenyl-1,2-benzoisoselenazol-3-(2H-one] analogue, C14H11NOSe, the benzisoselenazolyl moiety (r.m.s. deviation = 0.0209 Å is nearly perpendicular to the N-arenyl ring, making a dihedral angle of 78.15 (11°. In the crystal, molecules are linked by C—H...O and Se...O interactions into chains along the c-axis direction. The Se...O distance [2.733 (3 Å] is longer than that in Ebselen (2.571 (3 Å].

Contribution of the pre-ionized H2 and the ionized H2+ subsystems to the HHG Spectra of H2 in intense laser fields

Science.gov (United States)

Iravani, Hossein; Sabzyan, Hassan; Vafaee, Mohsen; Buzari, Behnaz

2018-04-01

Contributions of the pre-ionized H2 (PI-H2) and ionized {{{H}}}2+ subsystems of the two-electron H2 system to its high-order harmonic generation in eight-cycle sin2-like ultrafast intense laser pulses are calculated and analyzed based on the solution of the time-dependent Schrödinger equation for the one-dimensional two-electronic H2 system with fixed nuclei. The laser pulses have λ = 390 and 532 nm wavelengths and I = 1 × 1014, 5 × 1014, 1 × 1015 and 5 × 1015 W cm‑2 intensities. It is found that at the two lower intensities, the PI-H2 subsystem dominantly produces the HHG spectra. However, at the two higher intensities, both PI-H2 and ionized {{{H}}}2+ subsystems contribute comparably to the HHG spectra. In the {{{H}}}2+ subsystem, the symmetry of the populations of {{{H}}}2+(I) and {{{H}}}2+(II) regions (left and right regions of {{{H}}}2+ subsystem) is broken by increasing the laser intensity. Complex patterns and even harmonics also appear at these two higher intensities. For instance, at 1 × 1015 W cm‑2 intensity and λ = 532 nm wavelength, the even harmonics are appeared near cutoff region. Interestingly, at 5 × 1015 W cm‑2 intensity and λ = 390 nm wavelength, the even harmonics replaced by the odd harmonics with red shift. At λ = 390 and 532 nm wavelengths and I = 1 × 1015 intensity, the two-electron cutoffs corresponding to nonsequential double-recombination with maximum return kinetic energy of 4.70Up are detected. The HHG spectra of the whole H2 system obtained with and without nuclear dynamics treated classically are approximately similar. However, at 1 × 1015 W cm‑2 intensity and λ = 532 nm wavelength, if we take into account nuclear dynamics, the even harmonics which are appeared near cutoff region, replaced by the odd harmonics with blue shift.

Emission analysis of Tb3+ -and Sm3+ -ion-doped (Li2 O/Na2 O/K2 O) and (Li2 O + Na2 O/Li2 O + K2 O/K2 O + Na2 O)-modified borosilicate glasses.

Science.gov (United States)

Naveen Kumar Reddy, B; Sailaja, S; Thyagarajan, K; Jho, Young Dahl; Sudhakar Reddy, B

2018-05-01

Four series of borosilicate glasses modified by alkali oxides and doped with Tb 3+ and Sm 3+ ions were prepared using the conventional melt quenching technique, with the chemical composition 74.5B 2 O 3 + 10SiO 2 + 5MgO + R + 0.5(Tb 2 O 3 /Sm 2 O 3 ) [where R = 10(Li 2 O /Na 2 O/K 2 O) for series A and C, and R = 5(Li 2 O + Na 2 O/Li 2 O + K 2 O/K 2 O + Na 2 O) for series B and D]. The X-ray diffraction (XRD) patterns of all the prepared glasses indicate their amorphous nature. The spectroscopic properties of the prepared glasses were studied by optical absorption analysis, photoluminescence excitation (PLE) and photoluminescence (PL) analysis. A green emission corresponding to the 5 D 4 → 7 F 5 (543 nm) transition of the Tb 3+ ions was registered under excitation at 379 nm for series A and B glasses. The emission spectra of the Sm 3+ ions with the series C and D glasses showed strong reddish-orange emission at 600 nm ( 4 G 5/2 → 6 H 7/2 ) with an excitation wavelength λ exci = 404 nm ( 6 H 5/2 → 4 F 7/2 ). Furthermore, the change in the luminescence intensity with the addition of an alkali oxide and combinations of these alkali oxides to borosilicate glasses doped with Tb 3+ and Sm 3+ ions was studied to optimize the potential alkali-oxide-modified borosilicate glass. Copyright © 2017 John Wiley & Sons, Ltd.

The synthesis of [2-3H2] taurine and [2-3H2] hypotaurine

International Nuclear Information System (INIS)

Fellman, J.H.

1981-01-01

The synthesis of [2- 3 H 2 ]-2-aminoethanesulfonate [2- 3 H]-taurine by the reduction of cyanomethanesulfonic acid with tritium gas is described. The conversion of [2- 3 H]-taurine and its 14 C and 35 S isotopic forms to 2-aminoethanesulfinate (hypotaurine) was accomplished by converting taurine to its corresponding sulfonyl chloride and reducing the latter with metallic zinc. (author)

Calculation of phase equilibria in the Na2SO4-K2SO4-Cs2SO4-H2O system at 25 deg C

International Nuclear Information System (INIS)

Filippov, V.K.; Kalinkin, A.M.; Vasin, S.K.

1990-01-01

Calculation results of solubility diagram and water activity in saturated solutions of Na 2 SO 4 -K 2 SO 4 -Cs 2 SO 4 -H 2 O system at 25 deg C are presented. It is shown that for the calculation of quaternary systems one can use the Pitzer equations. Solubility diagram for the system studied is plotted and data on composition and water activity of solutions saturated by two or three solid phases are given. Classification of nonvariant equilibria from the viewpoint of isomorphism of solubility and fusibility diagrams permits to depict the direction of phase processes during isothermal evaporation of water

An open-framework three-dimensional indium oxalate: [In(OH)(C2O4)(H2O)]3.H2O

International Nuclear Information System (INIS)

Yang Sihai; Li Guobao; Tian Shujian; Liao Fuhui; Lin Jianhua

2005-01-01

By hydrothermal reaction of In 2 O 3 with H 2 C 2 O 4 .2H 2 O in the presence of H 3 BO 3 at 155 deg. C, an open-framework three-dimensional indium oxalate of formula [In(OH)(C 2 O 4 )(H 2 O)] 3 .H 2 O (1) has been obtained. The compound crystallizes in the trigonal system, space group R3c with a=18.668(3)A, c=7.953(2)A, V=2400.3(7)A 3 , Z=6, R 1 =0.0352 at 298K. The small pores in 1 are filled with water molecules. It loses its filled water at about 180 deg. C without the change of structure, then the bounded water at 260 deg. C, and completely decompounds at 324 deg. C. The residue is confirmed to be In 2 O 3

Imaging responses of on-site CsI and Gd2O2S flat-panel detectors: Dependence on the tube voltage

Science.gov (United States)

Jeon, Hosang; Chung, Myung Jin; Youn, Seungman; Nam, Jiho; Lee, Jayoung; Park, Dahl; Kim, Wontaek; Ki, Yongkan; Kim, Ho Kyung

2015-07-01

One of the emerging issues in radiography is low-dose imaging to minimize patient's exposure. The scintillating materials employed in most indirect flat-panel detectors show a drastic change of X-ray photon absorption efficiency around their K-edge energies that consequently affects image quality. Using various tube voltages, we investigated the imaging performance of most popular scintillators: cesium iodide (CsI) and gadolinium oxysulfide (Gd2O2S). The integrated detective quantum efficiencies (iDQE) of four detectors installed in the same hospital were evaluated according to the standardized procedure IEC 62220-1 at tube voltages of 40 - 120 kVp. The iDQE values of the Gd2O2S detectors were normalized by those of CsI detectors to exclude the effects of image postprocessing. The contrast-to-noise ratios (CNR) were also evaluated by using an anthropomorphic chest phantom. The iDQE of the CsI detector outperformed that of the Gd2O2S detector over all tube voltages. Moreover, we noted that the iDQE of the Gd2O2S detectors quickly rolled off with decreasing tube voltage under 70 kVp. The CNRs of the two scintillators were similar at 120 kVp. At 60 kVp, however, the CNR of Gd2O2S was about half that of CsI. Compared to the Gd2O2S detectors, variations in the DQE performance of the CsI detectors were relatively immune to variations in the applied tube voltages. Therefore, we claim that Gd2O2S detectors are inappropriate for use in low-tube-voltage imaging (e.g., extremities and pediatrics) with low patient exposure.

Collisional energy transfer between highly excited vibrational levels of K2 (11Σu+, V=46∼61) and H2

International Nuclear Information System (INIS)

Zhang Liping; Cai Qin; Luan Nannan; Dai Kang; Shen Yifan

2011-01-01

Using the CARS (Coherent Anti-stokes Raman Spectroscopy) detection technique, the electronic-to-rovibrational levels energy transfer between electronically excited K 2 (which is in the state of 1 1 ∑ u + , V=46∼61) and H 2 has been investigated. The scanned CARS spectra reveals that H 2 molecules are produced only at the V=1, J=2 and V=2, J=0, 1, 2 rovibrational levels during energy transfer processes. From scanned CARS spectral peaks the population ratios are obtained. The n 1 /n 4 9 n 2 /n 4 , and n 3 /n 4 are 3.3±0.5, 2.2±0.3 and 2.0±0.3, respectively, where n 1 , n 2 , n 3 and n 4 represent the number densities of H 2 at rovibrational levels (2, 0), (2, 1), (2, 2) and (1, 2), respectively. The population ratios indicate that the H 2 molecules produced by the energy transfer process are 88% populated at the V=2 level and 12% at V=1. The relative fractions (, , ) of average energy disposal are derived as (0.53, 0.01, 0.46), having major vibrational and translational energy release. Through simple kinetic model at the experimental conditions of T=573 K and P(H 2 ) =5 X 10 3 Pa, collisional transfer rate coefficients k 12 =(3.3±0.7) X 10 -14 and k 2 =(1.4±0.3) X 10 -14 cm 3 s -1 have been obtained. (authors)

Relationship between C2H2 reduction, H2 evolution and 15N2 fixation in root nodules of pea (Pisum sativum)

DEFF Research Database (Denmark)

Skøt, Leif

1983-01-01

for N2 reduction, is often stated as the relative efficiency (1-H2/C2H2). This factor varied significantly (P 2 and N2, expressed as the H2/N2 ratio, was independent of plant age, however. This discrepancy and the observation......The quantitative relationship between C2H2 reduction, H2 evolution and 15N2 fixation was investigated in excised root nodules from pea plants (Pisum sativum L. cv. Bodil) grown under controlled conditions. The C2H2/N2 conversion factor varied from 3.31 to 5.12 between the 32nd and the 67th day...... after planting. After correction for H2 evolution in air, the factor (C2H2-H2)/N2 decreased to values near the theoretical value 3, or in one case to a value significantly (P 2 production but used...

Catalytical conversion from ortho-H2 to para-H2

International Nuclear Information System (INIS)

Corat, E.J.

1984-01-01

The classical theory of ortho to para-H 2 conversion is discussed, considering the catalytical action of an inhomogeneous magnetic field on a surface with magnetic particles. In particular, the use of charcoal as a catalyst at low temperatures (77 0 K) is considered and some results are presented. The development of a sensor for the determination of para-H 2 concentration in H 2 gas is studied. Experimental results with this sensor are also shown. (Author) [pt

Fingerprints of field-induced Berezinskii–Kosterlitz–Thouless transition in quasi-two-dimensional S=1/2 Heisenberg magnets Cu(en)(H2O)2SO4 and Cu(tn)Cl2

International Nuclear Information System (INIS)

Baranová, Lucia; Orendáčová, Alžbeta; Čižmár, Erik; Tarasenko, Róbert; Tkáč, Vladimír; Orendáč, Martin; Feher, Alexander

2016-01-01

Organo-metallic compounds Cu(en)(H 2 O) 2 SO 4 (en=C 2 H 8 N 2 ) and Cu(tn)Cl 2 (tn=C 3 H 10 N 2 ) representing S=1/2 quasi-two-dimensional Heisenberg antiferromagnets with an effective intra-layer exchange coupling J/k B ≈3 K, have been examined by specific heat measurements at temperatures down to nominally 50 mK and magnetic fields up to 14 T. A comparative analysis of magnetic specific heat in zero magnetic field revealed nearly identical contribution of short-range magnetic correlations and significant differences were observed at lowest temperatures. A phase transition to long-range order was observed in Cu(en)(H 2 O) 2 SO 4 at T C =0.9 K while hidden in Cu(tn)Cl 2 . A response of both compounds to the application of magnetic field has rather universal features characteristic for a field-induced Berezinskii–Kosterlitz–Thouless transition theoretically predicted for ideal two-dimensional magnets. - Highlights: • Magnetic specific heat of Cu(en)(H 2 O) 2 SO 4 (1) and Cu(tn)Cl 2 (2) was analysed. • In zero magnetic field, (1) and (2) behave as quasi-two-dimensional magnets. • We observed universal thermodynamic response of (1) and (2) to applied field. • Features of field-induced Berezinskii–Kosterlitz–Thouless transition were detected.

Magnetocaloric effect in gadolinium-oxalate framework Gd2(C2O4)3(H2O)6⋅(0⋅6H2O)

International Nuclear Information System (INIS)

Sibille, Romain; Didelot, Emilie; Mazet, Thomas; Malaman, Bernard; François, Michel

2014-01-01

Magnetic refrigerants incorporating Gd 3+ ions and light organic ligands offer a good balance between isolation of the magnetic centers and their density. We synthesized the framework material Gd 2 (C 2 O 4 ) 3 (H 2 O) 6 ⋅0.6H 2 O by a hydrothermal route and characterized its structure. The honeycomb lattice of Gd 3+ ions interlinked by oxalate ligands in the (a,c) plane ensures their decoupling in terms of magnetic exchange interactions. This is corroborated by magnetic measurements indicating negligible interactions between the Gd 3+ ions in this material. The magnetocaloric effect was evaluated from isothermal magnetization measurements. The maximum entropy change −ΔS M max reaches 75.9 mJ cm −3 K −1 (around 2 K) for a moderate field change (2 T)

K2-155

DEFF Research Database (Denmark)

Hirano, Teruyuki; Dai, Fei; Livingston, John H.

2018-01-01

We report on the discovery of three transiting super-Earths around K2-155 (EPIC 210897587), a relatively bright early M dwarf (V = 12.81 mag) observed during Campaign 13 of the NASA K2 mission. To characterize the system and validate the planet candidates, we conducted speckle imaging and high......-dispersion optical spectroscopy, including radial velocity measurements. Based on the K2 light curve and the spectroscopic characterization of the host star, the planet sizes and orbital periods are 1.55(-0.17)(+0.20) R-circle plus and 6.34365 +/- 0.00028 days for the inner planet; 1.95(-0.22)(+0.27) R-circle plus...... and 13.85402 +/- 0.00088 days for the middle planet; and 1.64(-0.17)(+0.18) R-circle plus and 40.6835 +/- 0.0031 days for the outer planet. The outer planet (K2-155d) is near the habitable zone, with an insolation 1.67 +/- 0.38 times that of the Earth. The planet's radius falls within the range between...

The reactions of SO3 with HO2 radical and H2O...HO2 radical complex. Theoretical study on the atmospheric formation of HSO5 and H2SO4.

Science.gov (United States)

Gonzalez, Javier; Torrent-Sucarrat, Miquel; Anglada, Josep M

2010-03-07

The influence of a single water molecule on the gas-phase reactivity of the HO(2) radical has been investigated by studying the reactions of SO(3) with the HO(2) radical and with the H(2)O...HO(2) radical complex. The naked reaction leads to the formation of the HSO(5) radical, with a computed binding energy of 13.81 kcal mol(-1). The reaction with the H(2)O...HO(2) radical complex can give two different products, namely (a) HSO(5) + H(2)O, which has a binding energy that is computed to be 4.76 kcal mol(-1) more stable than the SO(3) + H(2)O...HO(2) reactants (Delta(E + ZPE) at 0K) and an estimated branching ratio of about 34% at 298K and (b) sulfuric acid and the hydroperoxyl radical, which is computed to be 10.51 kcal mol(-1) below the energy of the reactants (Delta(E + ZPE) at 0K), with an estimated branching ratio of about 66% at 298K. The fact that one of the products is H(2)SO(4) may have relevance in the chemistry of the atmosphere. Interestingly, the water molecule acts as a catalyst, [as it occurs in (a)] or as a reactant [as it occurs in (b)]. For a sake of completeness we have also calculated the anharmonic vibrational frequencies for HO(2), HSO(5), the HSO(5)...H(2)O hydrogen bonded complex, H(2)SO(4), and two H(2)SO(4)...H(2)O complexes, in order to help with the possible experimental identification of some of these species.

Uranous nitrate production using PtO2 catalyst and H2/H2 gas mixtures

International Nuclear Information System (INIS)

Rao, K.S.; Shyamlal, R.; Narayanan, C.V.; Patil, A.R.; Ramanujam, A.; Kansra, V.P.; Balu, K.; Vaidya, V.N.

2001-01-01

The feasibility of producing near 100% uranous nitrate, the partitioning agent used in the spent fuel reprocessing by Purex process, by catalytically reducing uranyl nitrate with H 2 and H 2 gas mixtures was extensively studied. As near quantitative reduction of uranyl nitrate could be easily achieved in laboratory scale studies, pilot plant scale reduction of uranyl nitrate was also carried out and five litres of uranyl nitrate of 100 g/1 could be quantitatively reduced in one hour. (author)

Scattering of near-zero-energy electrons and positrons by H2

KAUST Repository

Zhang, J.-Y.

2014-04-15

The parameters for S-wave elastic scattering of near-zero-energy electrons and positrons by H2 molecules are calculated using the stabilization method with explicitly correlated Gaussians. The confined variational method is applied to optimize the Gaussians to describe the short-range interaction of incident e± with H2 in the fixed-nuclei approximation. For e+-H2 scattering the scattering length of previous work [Phys. Rev. Lett. 103, 223202 (2009)] is substantially improved. More importantly, for e−-H2 scattering, from first principles, the scattering length is computed as a function of the internuclear distance. In the case that the two nuclei are at the equilibrium distance the results are in a good agreement with values derived from fitting experimental total and diffusion cross sections to the modified effective range theory.

Scattering of near-zero-energy electrons and positrons by H2

KAUST Repository

Zhang, J.-Y.; Yang, Y.-J.; Qian, Y.; Yan, Z.-C.; Schwingenschlö gl, Udo

2014-01-01

The parameters for S-wave elastic scattering of near-zero-energy electrons and positrons by H2 molecules are calculated using the stabilization method with explicitly correlated Gaussians. The confined variational method is applied to optimize the Gaussians to describe the short-range interaction of incident e± with H2 in the fixed-nuclei approximation. For e+-H2 scattering the scattering length of previous work [Phys. Rev. Lett. 103, 223202 (2009)] is substantially improved. More importantly, for e−-H2 scattering, from first principles, the scattering length is computed as a function of the internuclear distance. In the case that the two nuclei are at the equilibrium distance the results are in a good agreement with values derived from fitting experimental total and diffusion cross sections to the modified effective range theory.

H2O2: A Dynamic Neuromodulator

Science.gov (United States)

Rice, Margaret E.

2012-01-01

Increasing evidence implicates hydrogen peroxide (H2O2) as an intra- and intercellular signaling molecule that can influence processes from embryonic development to cell death. Most research has focused on relatively slow signaling, on the order of minutes to days, via second messenger cascades. However, H2O2 can also mediate subsecond signaling via ion channel activation. This rapid signaling has been examined most thoroughly in the nigrostriatal dopamine (DA) pathway, which plays a key role in facilitating movement mediated by the basal ganglia. In DA neurons of the substantia nigra, endogenously generated H2O2 activates ATP-sensitive K+ (KATP) channels that inhibit DA neuron firing. In the striatum, H2O2 generated downstream from glutamatergic AMPA receptor activation in medium spiny neurons acts as a diffusible messenger that inhibits axonal DA release, also via KATP channels. The source of dynamically generated H2O2 is mitochondrial respiration; thus, H2O2 provides a novel link between activity and metabolism via KATP channels. Additional targets of H2O2 include transient receptor potential (TRP) channels. In contrast to the inhibitory effect of H2O2 acting via KATP channels, TRP channel activation is excitatory. This review describes emerging roles of H2O2 as a signaling agent in the nigrostriatal pathway and other basal ganglia neurons. PMID:21666063

Studies on (2UF4 + H2 = 2UF3 + 2HF) and vapour pressure of UF3

International Nuclear Information System (INIS)

Roy, K.N.; Prasad, R.; Venugopal, V.; Singh, Z.; Sood, D.D.

1982-01-01

Equilibrium constants for 2UF 4 (s) + H 2 (g) = 2UF 3 (s) + 2HF(g) have been measured in the temperature range 967 to 1120 K. An expression is given for the results. The results have been treated by second- and third-law methods to obtain ΔH 0 (298.15 K) and the values are given. The value of ΔS 0 (298.15 K) has been calculated by the second-law method. An expression is given for the vapour pressure of UF 3 (s), measured by the transpiration technique in the range 1229 to 1367 K. The standard enthalpy of vaporization ΔH 0 sub(v) (298.15 K) and the standard entropy of vaporization ΔS 0 sub(v) (298.15 K) have been calculated. The vaporization results have also been used for the calculation of ΔH 0 sub(f)(UF 3 , g, 298.15 K) and ΔS 0 sub(f)(UF 3 ,g, 298.15 K). (author)

The first 3D malonate bridged copper [Cu(O2C–CH2–CO2H)2·2H2O]: Structure, properties and electronic structure

International Nuclear Information System (INIS)

Seguatni, A.; Fakhfakh, M.; Smiri, L.S.; Gressier, P.; Boucher, F.; Jouini, N.

2012-01-01

A new inorganic-organic compound [Cu(O 2 C–CH 2 –CO 2 H) 2 ·2H 2 O] ([Cumal]) was hydrothermally synthesized and characterized by IR spectroscopy, thermal analysis and single crystal X-ray diffraction. [Cumal] is the first three-dimensional compound existing in the system Cu(II)–malonic acid–H 2 O. Its framework is built up through carboxyl bridged copper where CuO 6 octahedra are elongated with an almost D 4h symmetry (4+2) due to the Jahn–Teller effect. The magnetic properties were studied by measuring its magnetic susceptibility in the temperature range of 2–300 K indicating the existence of weak ferromagnetic interactions. The electronic structure of [Cumal] was calculated within the density functional theory (DFT) framework. Structural features are well reproduced using DFT structural optimizations and the optical spectra, calculated within the dielectric formalism, explain very well the light blue colour of the compound. It is shown that a GGA+U approach with a U eff value of about 6 eV is necessary for a better correlation with the experiment. - Graphical abstract: [Cu(O 2 C–CH 2 –CO 2 H) 2 ·2H 2 O]: the first 3D hybrid organic–inorganic compound built up carboxyl groups. The network presents a diamond-like structure achieved via carboxyl. Highlights: ► A new organic–inorganic material with an unprecedented topology is synthesized. ► Crystallographic structure is determined using single crystal X-ray diffraction. ► Electronic structure is obtained from DFT, GGA+U calculation. ► Framework can be described as formed from CuC 4 tetrahedron sharing four corners. ► This structure can be classified as an extended diamond structure.

Structure of LaH(PO3H)2.3H2O

International Nuclear Information System (INIS)

Loukili, M.; Durand, J.; Larbot, A.; Cot, L.; Rafiq, M.

1991-01-01

Lanthanum hydrogen bis(hydrogenphosphite) trihydrate, LaH(Po 3 H) 2 .3H 2 O, M r =353.8, monoclinic, P2 1 /c, a=9.687 (3), b=7.138 (2), c=13.518 A, β=104.48 (3) deg, V=905.0 (5) A 3 , Z=4, D m =2.56 (2), D x =2.598 Mg m -3 , λ(MoKα)=0.71073 A, μ(MoKα)=5.103 mm -1 , F(000)=672, T=300 K, R=0.032 for 1018 independent observed reflections. The structure contains two phosphite anions connected by a hydrogen bond. The La 3+ cation is eight coordinated by seven O atoms from phosphite anions and one O atom of a water molecule. (orig.)

2Kx2K resolution element photon counting MCP sensor with >200 kHz event rate capability

CERN Document Server

Vallerga, J V

2000-01-01

Siegmund Scientific undertook a NASA Small Business Innovative Research (SBIR) contract to develop a versatile, high-performance photon (or particle) counting detector combining recent technical advances in all aspects of Microchannel Plate (MCP) detector development in a low cost, commercially viable package that can support a variety of applications. The detector concept consists of a set of MCPs whose output electron pulses are read out with a crossed delay line (XDL) anode and associated high-speed event encoding electronics. The delay line anode allows high-resolution photon event centroiding at very high event rates and can be scaled to large formats (>40 mm) while maintaining good linearity and high temporal stability. The optimal sensitivity wavelength range is determined by the choice of opaque photocathodes. Specific achievements included: spatial resolution of 200 000 events s sup - sup 1; local rates of >100 events s sup - sup 1 per resolution element; event timing of <1 ns; and low background ...

Effects of pH and H2O2 on ammonia, nitrite, and nitrate transformations during UV254nm irradiation: Implications to nitrogen removal and analysis.

Science.gov (United States)

Wang, Junli; Song, Mingrui; Chen, Baiyang; Wang, Lei; Zhu, Rongshu

2017-10-01

In order to achieve better removal and analyses of three dissolved inorganic nitrogen (DIN) species via ultraviolet-activated hydrogen peroxide (UV/H 2 O 2 ) process, this study systematically investigated the rates of photo-oxidations of ammonia/ammonium (NH 3 /NH 4 + ) and nitrite (NO 2 - ) as well as the photo-reduction of nitrate (NO 3 - ) at varying pH and H 2 O 2 conditions. The results showed that the mass balances of nitrogen were maintained along irradiation despite of interconversions of DIN species, suggesting that no nitrogen gas (N 2 ) or other nitrogen-containing compound was formed. NH 3 was more reactive than NH 4 + with hydroxyl radical (OH), and by a stepwise H 2 O 2 addition method NH 3 /NH 4 + can be completely converted to NO x - ; NO 2 - underwent rapid oxidation to form NO 3 - when H 2 O 2 was present, suggesting that it is an intermediate compound linking NH 3 /NH 4 + and NO 3 - ; but once H 2 O 2 was depleted, NO 3 - can be gradually photo-reduced back to NO 2 - at high pH conditions. Other than H 2 O 2 , the transformation kinetics of DINs were all dependent on pH, but to varying aspects and extents: the NH 3 photo-oxidation favored a pH of 10.3, which fell within the pK a values of NH 4 + (9.24) and H 2 O 2 (11.6); the NO 3 - photo-reduction increased with increasing pH provided that it exceeds the pK a of peroxynitrous acid (6.8); while the NO 2 - photo-oxidation remained stable unless the pH neared the pK a of H 2 O 2 (11.6). The study thereby demonstrates a picture of the evolutions of DIN species together during UV/H 2 O 2 irradiation process, and for the first time presents a method to achieve complete conversion of NH 4 + to NO 3 - with UV/H 2 O 2 process. Copyright © 2017 Elsevier Ltd. All rights reserved.

RG domain wall for the general (su)-hat (2) coset models

Energy Technology Data Exchange (ETDEWEB)

Stanishkov, Marian [Institute for Nuclear Research and Nuclear Energy,Bulgarian Academy of Sciences, 1784 Sofia (Bulgaria)

2016-08-16

We consider a RG flow in a general (su)-hat (2) coset model induced by the least relevant field. This is done using two different approaches. We first compute the mixing coefficients of certain fields in the UV and IR theories using a conformal perturbation theory. The necessary structure constants are computed. The same coefficients can be calculated using the RG domain wall construction of Gaiotto. We compute the corresponding one-point functions and show that the two approaches give the same result in the leading order.

K2 & Solar System Science

Science.gov (United States)

Lissauer, Jack

2015-01-01

All of the fields that K2 observes are near the ecliptic plane in order to minimize the spin-up of the spacecraft in response to the effects of solar irradiation. The fields observed by K2 are thus rich in Solar System objects including planets, asteroids and trans-Neptunian objects (TNOs). K2 has already performed observations of Neptune and its large moon Triton, 68 Trojan and Hilda asteroids, 5 TNOs (including Pluto) and Comet C/2013 A1 (Siding Springs). About 10,000 main-belt asteroids that fell into the pixel masks of stars have been serendipitously observed. Observations of small bodies are especially useful for determining rotation periods. Uranus will be observed in a future campaign (C8), as will many more small Solar System bodies. The status of various K2 Solar System studies will be reviewed and placed within the context of our current knowledge of the objects being observed.

Reaction rate and isomer-specific product branching ratios of C2H + C4H8: 1-butene, cis-2-butene, trans-2-butene, and isobutene at 79 K.

Science.gov (United States)

Bouwman, Jordy; Fournier, Martin; Sims, Ian R; Leone, Stephen R; Wilson, Kevin R

2013-06-20

The reactions of C2H radicals with C4H8 isomers 1-butene, cis-2-butene, trans-2-butene, and isobutene are studied by laser photolysis-vacuum ultraviolet mass spectrometry in a Laval nozzle expansion at 79 K. Bimolecular-reaction rate constants are obtained by measuring the formation rate of the reaction product species as a function of the reactant density under pseudo-first-order conditions. The rate constants are (1.9 ± 0.5) × 10(-10), (1.7 ± 0.5) × 10(-10), (2.1 ± 0.7) × 10(-10), and (1.8 ± 0.9) × 10(-10) cm(3) s(-1) for the reaction of C2H with 1-butene, cis-2-butene, trans-2-butene, and isobutene, respectively. Bimolecular rate constants for 1-butene and isobutene compare well to values measured previously at 103 K using C2H chemiluminescence. Photoionization spectra of the reaction products are measured and fitted to ionization spectra of the contributing isomers. In conjunction with absolute-ionization cross sections, these fits provide isomer-resolved product branching fractions. The reaction between C2H and 1-butene yields (65 ± 10)% C4H4 in the form of vinylacetylene and (35 ± 10)% C5H6 in the form of 4-penten-1-yne. The cis-2-butene and trans-2-butene reactions yield solely 3-penten-1-yne, and no discrimination is made between cis- and trans-3-penten-1-yne. Last, the isobutene reaction yields (26 ± 15)% 3-penten-1-yne, (35 ± 15)% 2-methyl-1-buten-3-yne, and (39 ± 15)% 4-methyl-3-penten-1-yne. The branching fractions reported for the C2H and butene reactions indicate that these reactions preferentially proceed via CH3 or C2H3 elimination rather than H-atom elimination. Within the experimental uncertainties, no evidence is found for the formation of cyclic species.

Composition of the volatile compounds from Aniba canelilla (H. B. K. Mez. extracted by CO2 in the supercritical state

Directory of Open Access Journals (Sweden)

Janete H. Y. Vilegas

Full Text Available The volatile compounds obtained by SFE-CO2 (supercritical fluid extraction utilizing CO2 from the barks of Aniba canelilla (H. B. K. Mez. (Lauraceae were analyzed by HRGC-FID (high resolution gas chromatography - flame ionization detector and HRGC-MS (high resolution gas chromatography -mass spectrometry. Phenylpropanoids and lower amounts of sesquiterpenoids, representing ca. 97% of the total oil, were identified. The main compound, 2-phenylnitroethane, corresponds to 71,12% of the total oil.

2,2-Dimethyl-2,3-dihydro-1H-perimidine

Directory of Open Access Journals (Sweden)

Sarah Maloney

2013-02-01

Full Text Available The title compound, C13H14N2, was obtained from reaction of diaminonaphthalene with acetone. In both independent molecules in the asymmetric unit, the tricyclic perimidine consists of a planar (r.m.s. deviations = 0.0125 and 0.0181 Å naphthalene ring system and an envelope conformation C4N2 ringwith the NCN group hinged with respect to the naphthalene backbone by 36.9 (2 and 41.3 (2° in the two independent molecules. The methyl substituents are arranged approximately axial and equatorial on the apical C atom. In the crystal, one of the N—H groups of one independent molecule is involved in classical N—H...N hydrogen bonding. Short intermolecular (C/N—H...π(arene interactions, near the short T-shaped limit, link molecules in the absence of strong acceptors.

Potassium Capture by Kaolin, Part 2: K2CO3, KCI, and K2SO4

DEFF Research Database (Denmark)

Wang, Guoliang; Jensen, Peter Arendt; Wu, Hao

2018-01-01

residence time on the reaction was investigated. The results showed that the K-capture level (C-K) (g potassium reacted by per g kaolin available) of K2CO3 and KCI by kaolin generally followed the equilibrium predictions at temperatures above 1100 degrees C, when using a kaolin particle size of D50 = 5.......47 mu m and a residence time of 1.2 s. This revealed that a nearly full conversion was obtained without kinetic or transport limitations at the conditions applied. At 800 and 900 degrees C, the measured conversions were lower than the equilibrium predictions, indicating that the reactions were either...

JMJD1B Demethylates H4R3me2s and H3K9me2 to Facilitate Gene Expression for Development of Hematopoietic Stem and Progenitor Cells

Directory of Open Access Journals (Sweden)

Sihui Li

2018-04-01

Full Text Available Summary: The arginine methylation status of histones dynamically changes during many cellular processes, including hematopoietic stem/progenitor cell (HSPC development. The arginine methyltransferases and the readers that transduce the histone codes have been defined. However, whether arginine demethylation actively occurs in cells and what enzyme demethylates the methylarginine residues during various cellular processes are unknown. We report that JMJD1B, previously identified as a lysine demethylase for H3K9me2, mediates arginine demethylation of H4R3me2s and its intermediate, H4R3me1. We show that demethylation of H4R3me2s and H3K9me2s in promoter regions is correlated with active gene expression. Furthermore, knockout of JMJD1B blocks demethylation of H4R3me2s and/or H3K9me2 at distinct clusters of genes and impairs the activation of genes important for HSPC differentiation and development. Consequently, JMJD1B−/− mice show defects in hematopoiesis. Altogether, our study demonstrates that demethylase-mediated active arginine demethylation process exists in eukaryotes and that JMJD1B demethylates both H4R3me2s and H3K9me2 for epigenetic programming during hematopoiesis. : Li et al. identify the arginine demethylase (RDM activity of JMJD1B, a known lysine demethylase (KDM. They reveal that JMJD1B actively mediates demethylation of histone markers H4R3me2s and H3K9me2 in hematopoietic stem/progenitor cells (HSPCs. Keywords: JMJD1B, KDM3B, PRMT5, arginine demethylase, histone, epigenetic programming, gene expression, hematopoiesis

Crystallization of rare earth germanates in the K2O-Ln2O3-GeO2-H2O at 280 deg C

International Nuclear Information System (INIS)

Panasenko, E.B.; Begunova, R.G.; Sklokina, N.F.

1980-01-01

Crystallization of rare earth germanates in potassium hydroxide solutions is studied at 280 deg C. Stability limits for different crystalline phases are established. Diorthogermanates Ln 2 O 3 x2GeO 3 (three structural modifications) are formed with all lanthanides except lanthanum. Germanates-apatites 7Ln 2 O 3 x9GeO 2 are characteristic for ''large'' lanthanides La-Nd. Alkali germanate of the composition 0.5 K 2 OxLn 2 O 3 xGeO 2 xnH 2 O is realized with the elements of the end of rare earth series, i.e., Tm-Lu. Some properties of the germanates synthesized are considered [ru

TASK-2: a K2P K+ channel with complex regulation and diverse physiological functions

Directory of Open Access Journals (Sweden)

Luis Pablo Cid

2013-07-01

Full Text Available TASK-2 (K2P5.1 is a two-pore domain K+ channel belonging to the TALK subgroup of the K2P family of proteins. TASK-2 has been shown to be activated by extra- and intracellular alkalinisation. Extra- and intracellular pH-sensors reside at arginine 224 and lysine 245 and might affect separate selectivity filter and inner gates respectively. TASK-2 is modulated by changes in cell volume and a regulation by direct G-protein interaction has also been proposed. Activation by extracellular alkalinisation has been associated with a role of TASK-2 in kidney proximal tubule bicarbonate reabsorption, whilst intracellular pH-sensitivity might be the mechanism for its participation in central chemosensitive neurons. In addition to these functions TASK-2 has been proposed to play a part in apoptotic volume decrease in kidney cells and in volume regulation of glial cells and T-lymphocytes. TASK-2 is present in chondrocytes of hyaline cartilage, where it is proposed to play a central role in stabilizing the membrane potential. Additional sites of expression are dorsal root ganglion neurons, endocrine and exocrine pancreas and intestinal smooth muscle cells. TASK-2 has been associated with the regulation of proliferation of breast cancer cells and could become target for breast cancer therapeutics. Further work in native tissues and cells together with genetic modification will no doubt reveal the details of TASK-2 functions that we are only starting to suspect.

K2V2O2(AsO42

Directory of Open Access Journals (Sweden)

Thierry Roisnel

2012-07-01

Full Text Available The vanadium oxide arsenate with formula K2V2O2(AsO42, dipotassium divanadium(IV dioxide diarsenate, has been synthesized by solid-state reaction in an evacuated silica ampoule. Its structure is isotypic with K2V2O2(PO42. The framework is built up from corner-sharing VO6 octahedra and AsO4 tetrahedra, creating an infinite [VAsO8]∞ chain running along the a- and c-axis directions. The K+ cations are located in hexagonal tunnels, which are delimited by the connection of the [VAsO8]∞ chains.

ZnO nanoneedle/H2O solid-liquid heterojunction-based self-powered ultraviolet detector

Science.gov (United States)

2013-01-01

ZnO nanoneedle arrays were grown vertically on a fluorine-doped tin oxide-coated glass by hydrothermal method at a relatively low temperature. A self-powered photoelectrochemical cell-type UV detector was fabricated using the ZnO nanoneedles as the active photoanode and H2O as the electrolyte. This solid-liquid heterojunction offers an enlarged ZnO/water contact area and a direct pathway for electron transport simultaneously. By connecting this UV photodetector to an ammeter, the intensity of UV light can be quantified using the output short-circuit photocurrent without a power source. High photosensitivity, excellent spectral selectivity, and fast photoresponse at zero bias are observed in this UV detector. The self-powered behavior can be well explained by the formation of a space charge layer near the interface of the solid-liquid heterojunction, which results in a built-in potential and makes the solid-liquid heterojunction work in photovoltaic mode. PMID:24103153

Calorimetric investigation into interaction in Zr0.8Ti0.2CrFe-H2 system

International Nuclear Information System (INIS)

Sirotina, R.A.; Verbetskij, V.N.

1993-01-01

For studying Zr 0.8 Ti 0.2 CrFe-H 2 system is applied the calorimetric method with usage of the Tian-Calve type calorimeter. It is shown that up to 488 K in the system there are three characteristic regions: α (hydrogen solution in an intermetallic compounds (IMC)), β (hydrogen solution in a hydride) and α + β (region of coexistence of two phases). Temperature 448 K is near to critical one, when exceeding of which exists only hydrogen solution in a metal matrix. Pressure dependence of hydrogen content in IMC is described satisfactorily by a linear equation

Fucoxanthin prevents H2O2-induced neuronal apoptosis via concurrently activating the PI3-K/Akt cascade and inhibiting the ERK pathway.

Science.gov (United States)

Yu, Jie; Lin, Jia-Jia; Yu, Rui; He, Shan; Wang, Qin-Wen; Cui, Wei; Zhang, Jin-Rong

2017-01-01

Background : As a natural carotenoid abundant in chloroplasts of edible brown algae, fucoxanthin possesses various health benefits, including anti-oxidative activity in particular. Objective : In the present study, we studied whether fucoxanthin protected against hydrogen peroxide (H 2 O 2 )-induced neuronal apoptosis. Design : The neuroprotective effects of fucoxanthin on H 2 O 2 -induced toxicity were studied in both SH-SY5Y cells and primary cerebellar granule neurons. Results : Fucoxanthin significantly protected against H 2 O 2 -induced neuronal apoptosis and intracellular reactive oxygen species. H 2 O 2 treatment led to the reduced activity of phosphoinositide 3-kinase (PI3-K)/Akt cascade and the increased activity of extracellular signal-regulated kinase (ERK) pathway in SH-SY5Y cells. Moreover, fucoxanthin significantly restored the altered activities of PI3-K/Akt and ERK pathways induced by H 2 O 2 . Both specific inhibitors of glycogen synthase kinase 3β (GSK3β) and mitogen-activated protein kinase kinase (MEK) significantly protected against H 2 O 2 -induced neuronal death. Furthermore, the neuroprotective effects of fucoxanthin against H 2 O 2 -induced neuronal death were abolished by specific PI3-K inhibitors. Conclusions : Our data strongly revealed that fucoxanthin protected against H 2 O 2 -induced neurotoxicity via concurrently activating the PI3-K/Akt cascade and inhibiting the ERK pathway, providing support for the use of fucoxanthin to treat neurodegenerative disorders induced by oxidative stress.

Photoluminescence and thermoluminescence of K2 Mg(SO4 )2 :Eu and evaluation of its kinetic parameters.

Science.gov (United States)

Deshpande, Archana; Dhoble, N S; Gedam, S C; Dhoble, S J

2017-08-01

The K 2 Mg(SO 4 ) 2 :Eu phosphor, synthesized by a solid-state diffusion method, was studied for its photoluminescence (PL) and thermoluminescence (TL) characteristics. The X-ray diffraction (XRD) pattern of the material was matched with the standard JCPDF No. 36-1499. For PL characteristics, K 2 Mg(SO 4 ) 2 :Eu 2 + showed an emission peak at 474 nm when excited at 340 nm, while it showed Eu 3 + emission at 580 nm, and 594 nm splitting at 613 nm and 618 nm for an excitation of 396 nm wavelength due to radiative transitions from 5 D 0 to 7 F j (j = 0, 1, 2, 3). The Commission International de I' Eclairage (CIE) chromaticity coordinates were also calculated for the K 2 Mg(SO 4 ) 2 :Eu phosphor, and were close to the NTSC standard values. For the TL study, the prepared sample was irradiated using a 60 Co source of γ-irradiation at the dose rate of 0.322 kGy/h for 2 min. The formation of traps in K 2 Mg (SO 4 ) 2 :Eu and the effects of γ-radiation dose on the glow curve are discussed. Well defined broad glow peaks were obtained at 186°C. With increasing γ-ray dose, the sample showed linearity in intensity. The presence of a single glow peak indicated that there was only one set of traps being activated within the particular temperature range. The presented phosphors were also studied for their fading, reusability and trapping parameters. There was just 2% fading during a period of 30 days, indicating no serious fading problem. Kinetic parameters were calculated using the initial rise method and Chen's half-width method. Activation energy and frequency factor were found to be 0.77 eV and 1.41 × 10 6  sec -1 . Copyright © 2016 John Wiley & Sons, Ltd.

Preparation of rat gastric heavy and light microsomal membranes enriched in (H+-K+)-ATPase using 2H2O and Percoll gradients

International Nuclear Information System (INIS)

Im, W.B.; Davis, J.P.; Blakeman, D.P.

1985-01-01

Gastric heavy microsomal membranes highly enriched in (H + -K + )-ATPase were obtained from cimetidine- or carbachol-treated rats through 2 H 2 O and Percoll gradient centrifugations. Both the resting (cimetidine-treated) and the stimulated (carbachol-treated) heavy membranes which presumably represent the apical membrane of gastric parietal cells were enriched with the polypeptides of 81,000 and 45,000 besides that of 93,000 representing (H + -K + )-ATPase. No apparent differences could be detected between the resting and the stimulated heavy membranes in their polypeptide profiles or their specific activity of (H + -K + )-ATPase. Nevertheless, the level of 86 RbCl uptake was greater in the stimulated than the resting heavy microsomal membrane vesicles. The light gastric microsomes which abound in intracellular tubulovesicles containing reserve (H + -K + )-ATPase as isolated from cimetidine-treated rats were similarly purified with respect to (H + -K + )-ATPase. The purified light gastric membranes were largely devoid of the polypeptides of 81,000 and 45,000 found in the heavy gastric membranes. These observations further support the current hypothesis that secretagogues bring about changes in the environment of (H + -K + )-ATPase and induce KCl permeability in the apical membrane of the parietal cells, although at present the authors have been unable to identify the polypeptide(s) responsible for the KCl pathway

Vibrations and reorientations of H2O molecules in [Sr(H2O)6]Cl2 studied by Raman light scattering, incoherent inelastic neutron scattering and proton magnetic resonance.

Science.gov (United States)

Hetmańczyk, Joanna; Hetmańczyk, Lukasz; Migdał-Mikuli, Anna; Mikuli, Edward; Florek-Wojciechowska, Małgorzata; Harańczyk, Hubert

2014-04-24

Vibrational-reorientational dynamics of H2O ligands in the high- and low-temperature phases of [Sr(H2O)6]Cl2 was investigated by Raman Spectroscopy (RS), proton magnetic resonance ((1)H NMR), quasielastic and inelastic incoherent Neutron Scattering (QENS and IINS) methods. Neutron powder diffraction (NPD) measurements, performed simultaneously with QENS, did not indicated a change of the crystal structure at the phase transition (detected earlier by differential scanning calorimetry (DSC) at TC(h)=252.9 K (on heating) and at TC(c)=226.5K (on cooling)). Temperature dependence of the full-width at half-maximum (FWHM) of νs(OH) band at ca. 3248 cm(-1) in the RS spectra indicated small discontinuity in the vicinity of phase transition temperature, what suggests that the observed phase transition may be associated with a change of the H2O reorientational dynamics. However, an activation energy value (Ea) for the reorientational motions of H2O ligands in both phases is nearly the same and equals to ca. 8 kJ mol(-1). The QENS peaks, registered for low temperature phase do not show any broadening. However, in the high temperature phase a small QENS broadening is clearly visible, what implies that the reorientational dynamics of H2O ligands undergoes a change at the phase transition. (1)H NMR line is a superposition of two powder Pake doublets, differentiated by a dipolar broadening, suggesting that there are two types of the water molecules in the crystal lattice of [Sr(H2O)6]Cl2 which are structurally not equivalent average distances between the interacting protons are: 1.39 and 1.18 Å. However, their reorientational dynamics is very similar (τc=3.3⋅10(-10) s). Activation energies for the reorientational motion of these both kinds of H2O ligands have nearly the same values in an experimental error limit: and equal to ca. 40 kJ mole(-1). The phase transition is not seen in the (1)H NMR spectra temperature dependencies. Infrared (IR), Raman (RS) and inelastic

Reactive scattering for H{sup -} + H{sub 2} and H{sup +} + H{sub 2} and its isotopologues. Classical versus quantum investigation

Energy Technology Data Exchange (ETDEWEB)

Wang, Dequan

2016-07-01

In the present doctoral thesis, the reactive scattering for H{sup -} + H{sub 2} and H{sup +} + H{sub 2} and its isotopologues were investigated using different methods to solve the equations describing classical and quantum mechanics. The studies aimed at providing insights into elementary reactions, and may even go beyond these to more complex chemical reactions. The main results in this dissertation can be summarized as follows: In Chapter 2 the equations solving problems in quasi-classical mechanics were described, which led to the definition of energy dependent reaction probabilities P{sub r}(E{sub rel}, v, j) = (N{sub r})/(N{sub tot}) and reaction cross sections σ{sub R} = πP{sub r}(E{sub rel}, v, j)b{sup 2}{sub max}. The formalism for time-dependent methods for the investigation of scattering processes was presented in Chapter 3. In this section we discussed how to use the time-dependent quantum wavepacket method to study the A-BC system. The dependence of the reaction probabilities P{sup J}{sub reac}(E) on the total angular momenta J was calculated to obtain information about the integral reactive cross section σ{sup tot}(E) = (π)/(k{sup 2}{sub vj})Σ{sub J}(2J + 1)P{sup J}{sub reac}(E). The potential energy surfaces (PESs) for H{sup +}{sub 3} and H{sup -}{sub 3} were described in Chapter 4. For the H{sup +}{sub 3} system, a cut through the potential energy surface (PES) in the asymptotic region was presented. For the H{sup -}{sub 3} system three available ab initio potential energy surfaces have been used in the applications: a) Staerck and Meyer (SM-PES), b) Panda and Sathyamurthy (PS-PES), and c) Ayouz et al. (AY-PES). The differences in the PESs were investigated. In the beginning of Chapter 5 the H{sup +} + H{sub 2}(v=0-5, j=0) collision was investigated nonadiabatically. By comparison of the reaction probabilities using adiabatic and non-adiabatic representations of the potential energy surfaces, it was found that, at low collision energies, the

First Anti-neutrino Oscillation Results from the T2K Experiment

CERN Multimedia

CERN. Geneva

2015-01-01

Neutrinos are some of the most abundant but yet most elusive particles in the universe. They have almost no mass, only interact weakly and relatively little is known about their properties. Furthermore it has been firmly established over the last decade that neutrinos can undergo flavour transitions as mass and flavor eigenstates are not identical. These neutrino oscillations have been studied using natural sources as well as nuclear reactors or with neutrinos produced at accelerators. T2K is a long baseline neutrino oscillation beam that uses a beam of muon (anti-)neutrinos that is directed form J-PARC at the east cost of Japan over a distance of almost 300 km to the SuperKamiokande water Cherenkov detector in the west. The facility is complemented by a near detector complex 280 m downstream of the neutrino production target to characterise the beam and the neutrino interaction dynamics. T2K has taken data with a muon neutrino beam since early 2010 and is studying the disappearance of muon neutrinos as well...

Reactions of POxCly- ions with O2(a 1[Delta]g), H2O, and Cl2 at 298 K

Science.gov (United States)

Midey, Anthony J.; Dotan, Itzhak; Viggiano, A. A.

2008-06-01

The rate constants and product branching ratios for the reactions of phosphorus oxychloride anions, POxCly- for x = 1-2 and y = 1-3, with O2(a 1[Delta]g), Cl2, and H2O have been measured in a selected ion flow tube (SIFT) at 298 K. A mixture of O2(a 1[Delta]g) in O2 has been produced using a recently designed chemical singlet oxygen generator (sparger) with an emission detection scheme adopted previously in our laboratory. The experiments continue a series of investigations into the oxidation reactions of POxCly- ions, searching for pathways to the terminal PO2- and PO3- ions observed in combustion chemistry with POCl3 present. None of the POxCly- ions react with H2O or O2(a 1[Delta]g). The O2(a 1[Delta]g) rate constants have a limit of <1 × 10-11 cm3 s-1, except for PO2Cl- where a limit of <5 × 10-11 cm3 s-1 has been determined. The H2O rate constants have limits of <1 × 10-11 cm3 s-1. All of the POxCly- ions react with Cl2, excluding PO3- and PO2Cl2-. Depending on the reactant ion, Cl-, Cl2- or PO2Cl2- product ions form.

Far-UV, visible, and near-IR reflectance spectra of frosts of H2O, CO2, NH3 and SO2

Science.gov (United States)

Hapke, B.; Wells, E.; Wagner, J.; Partlow, W.

1981-01-01

Measurements in the 0.1-2.5 micron range are presented for the reflectance spectra of the frosts of several volatiles pertinent to the study of comet nuclei. The frost spectra have distinctive features permitting their identification by spectroscopic reflectance remote sensing, notably in the far UV. It is found that: (1) H2O has a minimum at 0.16 microns and a maximum at 0.13 microns; (2) CO2 has minima near 0.21, 0.18 and 0.125 microns, with maxima at 0.19, 0.135 and 0.120 microns; (3) NH3 is bright at wavelengths longer than 0.21 microns, where reflectance drops to a value of only a few per cent at shorter wavelengths; (4) SO2 has a sharp drop at 0.32 microns, with a minimum at 0.18 microns and a maximum at 0.13 microns. The features in the frost spectra largely correspond to absorption line bands in the gas phase.

High-gradient operators in the psl(2|2 Gross–Neveu model

Directory of Open Access Journals (Sweden)

Alessandra Cagnazzo

2015-03-01

Full Text Available It has been observed more than 25 years ago that sigma model perturbation theory suffers from strongly RG-relevant high-gradient operators. The phenomenon was first seen in 1-loop calculations for the O(N vector model and it is known to persist at least to two loops. More recently, Ryu et al. suggested that a certain deformation of the psl(N|N WZNW-model at level k=1, or equivalently the psl(N|N  Gross–Neveu model, could be free of RG-relevant high-gradient operators and they tested their suggestion to leading order in perturbation theory. In this note we establish the absence of strongly RG-relevant high-gradient operators in the psl(2|2 Gross–Neveu model to all loops. In addition, we determine the spectrum for a large subsector of the model at infinite coupling and observe that all scaling weights become half-integer. Evidence for a conjectured relation with the CP1|2 sigma model is not found.

Relationship between interlayer hydration and photocatalytic water splitting of A'1-xNaxCa2Ta3O10.nH2O (A'=K and Li)

International Nuclear Information System (INIS)

Mitsuyama, Tomohiro; Tsutsumi, Akiko; Sato, Sakiko; Ikeue, Keita; Machida, Masato

2008-01-01

Partial replacement of alkaline metals in anhydrous KCa 2 Ta 3 O 10 and LiCa 2 Ta 3 O 10 was studied to control interlayer hydration and photocatalytic activity for water splitting under UV irradiation. A' 1-x Na x Ca 2 Ta 3 O 10 .nH 2 O (A'=K and Li) samples were synthesized by ion exchange of CsCa 2 Ta 3 O 10 in mixed molten nitrates at 400 deg. C. In K 1-x Na x Ca 2 Ta 3 O 10 .nH 2 O, two phases with the orthorhombic (C222) and tetragonal (I4/mmm) structures were formed at x≤0.7 and x≥0.5, respectively. Upon replacement by Na + having a larger enthalpy of hydration (ΔH h 0 ), the interlayer hydration occurred at x≥0.3 and the hydration number (n) was increased monotonically with an increase of x. Li 1-x Na x Ca 2 Ta 3 O 10 .nH 2 O showed a similar hydration behavior, but the phase was changed from I4/mmm (x 1-x Na x Ca 2 Ta 3 O 10 .nH 2 O exhibited the activity increasing in consistent with n, whereas Li 1-x Na x Ca 2 Ta 3 O 10 .nH 2 O exhibited the activity maximum at x=0.77, where the rates of H 2 /O 2 evolution were nearly doubled compared with those for end-member compositions (x=0 and 1). - Graphical abstract: The partial substitution of Na in the interlayer of anhydrous-layered perovskite has been found as useful structural modification toward highly active hydrated photocatalysts

Investigation of the Na2(H2PO2)2 - Ba(H2PO2)2 - H2O Water-Salt Ternary System at Room Temperature

OpenAIRE

Erge, Hasan; Turan, Hakan; Kul, Ali Riza

2016-01-01

Objective: In this study, the solubility, density, conductivity and phase equilibria of the Na2(H2PO2)2-Ba(H2PO2)2-H2O ternary system located in the structure of the Na+, Ba2+, (H2PO2)-//H2O quaternary reciprocal water-salt system were investigated using physicochemical analysis methods. Material and Methods: Riedel-de Haen and Merck salts were used to investigate the solubility and phase equilibria of the Na2(H2PO2)2 -Ba(H2PO2)2-H2O ternary water–salt system at room temperature Res...

MeB5O8(Me-Li, Na, K, NH4)-H2NCONHCOCH3-H2O system at 25 deg C

International Nuclear Information System (INIS)

Skvortsov, V.G.; Fedorov, Yu.A.; Molodkin, A.K.; Tsekhanskij, R.S.

1986-01-01

Using the methods of isothermal solubility, densi- and refractometry, systems MB 5 O 8 (M-Li, Na, K, NH 4 )-acetylcarbamide - H 2 O at 25 deg C have been studied. It is ascertained, that the systems investigated are of simple eutonic type

Vibrational spectra of Cs2Cu(SO4)2·6H2O and Cs2Cu(SeO4)2·nH2O (n = 4, 6) with a crystal structure determination of the Tutton salt Cs2Cu(SeO4)2·6H2O

Science.gov (United States)

Wildner, M.; Marinova, D.; Stoilova, D.

2016-02-01

The solubility in the three-component systems Cs2SO4-CuSO4-H2O and Cs2SeO4-CuSeO4-H2O have been studied at 25 °C. The experimental results show that double salts, Cs2Cu(SO4)2·6H2O and Cs2Cu(SeO4)2·4H2O, crystallize from the ternary solutions within large concentration ranges. Crystals of Cs2Cu(SeO4)2·6H2O were synthesized at somewhat lower temperatures (7-8 °C). The thermal dehydration of the title compounds was studied by TG, DTA and DSC methods and the respective dehydration schemes are proposed. The calculated enthalpies of dehydration (ΔHdeh) have values of: 434.2 kJ mol-1 (Cs2Cu(SeO4)2·6H2O), 280.9 kJ mol-1 (Cs2Cu(SeO4)2·4H2O), and 420.2 kJ mol-1 (the phase transition of Cs2Cu(SO4)2·6H2O into Cs2Cu(SO4)2·H2O). The crystal structure of Cs2Cu(SeO4)2ṡ6H2O was determined from single crystal X-ray diffraction data. It belongs to the group of Tutton salts, crystallizing isotypic to the respective sulfate in a monoclinic structure which is characterized by isolated Cu(H2O)6 octahedra and SeO4 tetrahedra, interlinked by hydrogen bonds and [9]-coordinated Cs+ cations. Infrared spectra of the cesium copper compounds are presented and discussed with respect to both the normal modes of the tetrahedral ions and the water molecules. The analysis of the infrared spectra of the double compounds reveals that the distortion of the selenate tetrahedra in Cs2Cu(SeO4)2·4H2O is stronger than those in Cs2Cu(SeO4)2·6H2O in agreement with the structural data. Matrix-infrared spectroscopy was applied to confirm this claim - Δν3 for SO4 2 - ions matrix-isolated in Cs2Cu(SeO4)2·6H2O has a value of 35 cm-1 and that of the same ions included in Cs2Cu(SeO4)2·4H2O - 84 cm-1. This spectroscopic finding is due to the formation of strong covalent bands Cu-OSO3 on one hand, and on the other to the stronger deformation of the host SeO4 2 - tetrahedra in Cs2Cu(SeO4)2·4H2O as compared to those in Cs2Cu(SeO4)2·6H2O. The strength of the hydrogen bonds as deduced from the

Crystal structure of Cs3H(SeO4)2 (T=295 K) and its changes in phase transformations

International Nuclear Information System (INIS)

Merinov, B.V.; Bolotina, N.B.; Baranov, A.I.; Shuvalov, L.A.

1988-01-01

Crystal structure of Cs 3 H(SeO 4 ) 2 3 phase at T=295 K is decoded by X-ray diffraction data. Monoclinic cell parameters are improved: a=10.903(3), b=6.390(8), c=8.452(2)A, β=112.46(1) deg, V=544 A 3 , Z=2, sp. gr. C2/m. Structural peculiarities of 3↔2↔1 phase transitions in Cs 3 H(SeO 4 ) 2 and proton conductivity mechanism in superionic phase are considered

Review of H2 and O2 detection in LWRS

International Nuclear Information System (INIS)

Neidel, E.C.; Castle, J.G. Jr.

1981-01-01

Hydrogen detection systems are being installed in existing LWR's and are being planned for new ones. This review summarizes the present status of instrument availability and of application in nuclear power plants. The H 2 sensors in most of the detection systems purchased to date by the nuclear utilities are being located outside of containment. The air sampled for each H 2 sensor is circulated outside to the analyzer and back through two pipes which penetrate the containment wall. The travel time for the air to reach the sensor increases the response time for H 2 detection by approximately one-half minute. A few of the utilities will operate their H 2 sensors inside LWR containment. Since these systems lack radiation-hardened electronics, they require multiple wire penetrations which considerably increase installation costs and reduce the attractiveness of these systems. One electric power utility has requested quotations from hydrogen detector manufacturers for hydrogen detection equipment with better performance and faster system response than that presently available commercially. The requested detector response time of 15 seconds or less would permit the decision delay prior to initiating hydrogen control measures to be on the order of one minute

Kinetic removal of haloacetonitrile precursors by photo-based advanced oxidation processes (UV/H2O2, UV/O3, and UV/H2O2/O3).

Science.gov (United States)

Srithep, Sirinthip; Phattarapattamawong, Songkeart

2017-06-01

The objective of the study is to evaluate the performance of conventional treatment process (i.e., coagulation, flocculation, sedimentation and sand filtration) on the removals of haloacetonitrile (HAN) precursors. In addition, the removals of HAN precursors by photo-based advanced oxidation processes (Photo-AOPs) (i.e., UV/H 2 O 2 , UV/O 3 , and UV/H 2 O 2 /O 3 ) are investigated. The conventional treatment process was ineffective to remove HAN precursors. Among Photo-AOPs, the UV/H 2 O 2 /O 3 was the most effective process for removing HAN precursors, followed by UV/H 2 O 2 , and UV/O 3 , respectively. For 20min contact time, the UV/H 2 O 2 /O 3 , UV/H 2 O 2 , and UV/O 3 suppressed the HAN formations by 54, 42, and 27% reduction. Increasing ozone doses from 1 to 5 mgL -1 in UV/O 3 systems slightly improved the removals of HAN precursors. Changes in pH (6-8) were unaffected most of processes (i.e., UV, UV/H 2 O 2 , and UV/H 2 O 2 /O 3 ), except for the UV/O 3 system that its efficiency was low in the weak acid condition. The pseudo first-order kinetic constant for removals of dichloroacetonitrile precursors (k' DCANFP ) by the UV/H 2 O 2 /O 3 , UV/H 2 O 2 and standalone UV systems were 1.4-2.8 orders magnitude higher than the UV/O 3 process. The kinetic degradation of dissolved organic nitrogen (DON) tended to be higher than the k' DCANFP value. This study firstly differentiates the kinetic degradation between DON and HAN precursors. Copyright © 2017 Elsevier Ltd. All rights reserved.

Hydrogenation and Deuteration of C{sub 2}H{sub 2} and C{sub 2}H{sub 4} on Cold Grains: A Clue to the Formation Mechanism of C{sub 2}H{sub 6} with Astronomical Interest

Energy Technology Data Exchange (ETDEWEB)

Kobayashi, Hitomi; Kawakita, Hideyo [Koyama Astronomical Observatory, Kyoto Sangyo University Motoyama, Kamigamo, Kita-ku, Kyoto 603-8555 (Japan); Hidaka, Hiroshi; Hama, Tetsuya; Watanabe, Naoki [Institute of Low Temperature Science, Hokkaido University N19-W8, Kita-ku, Sapporo, Hokkaido 060-0819 (Japan); Lamberts, Thanja; Kästner, Johannes, E-mail: h_kobayashi@kyoto-nijikoubou.com [Institute for Theoretical Chemistry, University of Stuttgart, Pfaffenwaldring 55, D-70569 Stuttgart (Germany)

2017-03-10

We quantitatively investigated the hydrogen addition reactions of acetylene (C{sub 2}H{sub 2}) and ethylene (C{sub 2}H{sub 4}) on amorphous solid water (ASW) at 10 and 20 K relevant to the formation of ethane (C{sub 2}H{sub 6}) on interstellar icy grains. We found that the ASW surface enhances the reaction rates for C{sub 2}H{sub 2} and C{sub 2}H{sub 4} by approximately a factor of 2 compared to those on the pure-solid C{sub 2}H{sub 2} and C{sub 2}H{sub 4} at 10 K, probably due to an increase in the sticking coefficient and adsorption energy of the H atoms on ASW. In contrast to the previous proposal that the hydrogenation rate of C{sub 2}H{sub 4} is orders of magnitude larger than that of C{sub 2}H{sub 2}, the present results show that the difference in hydrogenation rates of C{sub 2}H{sub 2} and C{sub 2}H{sub 4} is only within a factor of 3 on both the surfaces of pure solids and ASW. In addition, we found the small kinetic isotope effect for hydrogenation/deuteration of C{sub 2}H{sub 2} and C{sub 2}H{sub 4} at 10 K, despite the requirement of quantum tunneling. At 20 K, the reaction rate of deuteration becomes even larger than that of hydrogenation. These unusual isotope effects might originate from a slightly larger number density of D atoms than H atoms on ASW at 20 K. The hydrogenation of C{sub 2}H{sub 2} is four times faster than CO hydrogenation and can produce C{sub 2}H{sub 6} efficiently through C{sub 2}H{sub 4} even in the environment of a dark molecular cloud.

The rate constant for the CO + H2O2 reaction

DEFF Research Database (Denmark)

Glarborg, Peter; Marshall, Paul

2009-01-01

The rate constant for the reaction CO + H2O2 -> HOCO + OH (R1) at 713 K is determined based on the batch reactor experiments of Baldwin et al. [ R. R. Baldwin, R. W. Walker, S. J. Webster, Combust. Flame 15 (1970) 167] on decomposition of H2O2 sensitized by CO. The value, k(1) (713 K) = 8.1 x 10...

Kinetic Studies of Iron Deposition Catalyzed by Recombinant Human Liver Heavy, and Light Ferritins and Azotobacter Vinelandii Bacterioferritin Using O2 and H2O2 as Oxidants

Science.gov (United States)

Bunker, Jared; Lowry, Thomas; Davis, Garrett; Zhang, Bo; Brosnahan, David; Lindsay, Stuart; Costen, Robert; Choi, Sang; Arosio, Paolo; Watt, Gerald D.

2005-01-01

The discrepancy between predicted and measured H2O2 formation during iron deposition with recombinant heavy human liver ferritin (rHF) was attributed to reaction with the iron protein complex [Biochemistry 40 (2001) 10832-10838]. This proposal was examined by stopped-flow kinetic studies and analysis for H2O2 production using (1) rHF, and Azotobacter vinelandii bacterial ferritin (AvBF), each containing 24 identical subunits with ferroxidase centers; (2) site-altered rHF mutants with functional and dysfunctional ferroxidase centers; and (3) rccombinant human liver light ferritin (rLF), containing 110 ferroxidase center. For rHF, nearly identical pseudo-first-order rate constants of 0.18 per second at pH 7.5 were measured for Fe(2+) oxidation by both O2 and H2O2, but for rLF, the rate with O2 was 200-fold slower than that for H2O2 (k-0.22 per second). A Fe(2+)/O2 stoichiometry near 2.4 was measured for rHF and its site altered forms, suggesting formation of H2O2. Direct measurements revealed no H2O2 free in solution 0.5-10 min after all Fe(2+) was oxidized at pH 6.5 or 7.5. These results are consistent with initial H2O2 formation, which rapidly reacts in a secondary reaction with unidentified solution components. Using measured rate constants for rHF, simulations showed that steady-state H2O2 concentrations peaked at 14 pM at approx. 600 ms and decreased to zero at 10-30 s. rLF did not produce measurable H2O2 but apparently conducted the secondary reaction with H2O2. Fe(2+)/O2 values of 4.0 were measured for AvBF. Stopped-flow measurements with AvBF showed that both H2O2 and O2 react at the same rate (k=0.34 per second), that is faster than the reactions with rHF. Simulations suggest that AvBF reduces O2 directly to H2O without intermediate H2O2 formation.

Crystal and molecular structure of 2,2’-(quinoxaline-2,3-diyl)dipyridinium dinitrate (H_2L)(NO_3)_2

International Nuclear Information System (INIS)

Egorova, O. A.; Polyakova, I. N.; Sergienko, V. S.; Davydov, V. V.

2016-01-01

The crystal structure of 2,2’-(quinoxaline-2,3-diyl)dipyridinium dinitrate (H_2L)(NO_3)_2 is studied by X-ray diffraction (T = 150 K, R1 = 0.0467). The H_2L"2"+ cation is located on the twofold rotation axis and connected with two NO_3"− anions by strong N–H···O hydrogen bonds. Planar quinoxaline fragments of cations form stacks with the interplanar spacing of 3.308 Å. The structure of the diprotonated H_2L"2"+ cation is compared with those of the monoprotonated H_2L"2"+ cation and neutral L molecule.

The Orion Fingers: H2 Temperatures and Excitation in an Explosive Outflow

Science.gov (United States)

Youngblood, Allison; France, Kevin; Ginsburg, Adam; Hoadley, Keri; Bally, John

2018-04-01

We measure H2 temperatures and column densities across the Orion Becklin-Neugebauer/Kleinmann-Low (BN/KL) explosive outflow from a set of 13 near-infrared (IR) H2 rovibrational emission lines observed with the TripleSpec spectrograph on Apache Point Observatory’s 3.5 m telescope. We find that most of the region is well characterized by a single temperature (∼2000–2500 K), which may be influenced by the limited range of upper-energy levels (6000–20,000 K) probed by our data set. The H2 column density maps indicate that warm H2 comprises 10‑5–10‑3 of the total H2 column density near the center of the outflow. Combining column density measurements for co-spatial H2 and CO at T = 2500 K, we measure a CO/H2 fractional abundance of 2 × 10‑3 and discuss possible reasons why this value is in excess of the canonical 10‑4 value, including dust attenuation, incorrect assumptions on co-spatiality of the H2 and CO emission, and chemical processing in an extreme environment. We model the radiative transfer of H2 in this region with ultraviolet (UV) pumping models to look for signatures of H2 fluorescence from H I Lyα pumping. Dissociative (J-type) shocks and nebular emission from the foreground Orion H II region are considered as possible Lyα sources. From our radiative transfer models, we predict that signatures of Lyα pumping should be detectable in near-IR line ratios given a sufficiently strong source, but such a source is not present in the BN/KL outflow. The data are consistent with shocks as the H2 heating source.

Two new barium-copper-ethylene glycol complexes: Synthesis and structure of BaCu(C2H6O2)n(C2H4O2)2 (N = 3, 6)

International Nuclear Information System (INIS)

Love, C.P.; Page, C.J.; Torardi, C.C.

1992-01-01

Two crystalline barium-copper-ethylene glycol complexes have been isolated and structurally characterized by single-crystal x-ray diffraction. The solution-phase complex has also been investigated as a molecular precursor for use in sol-gel synthesis of high-temperature superconductors. The first crystalline form has the formula BaCu(C 2 H 6 O 2 ) 6 (C 2 H 4 O 2 ) 2 (1) and has been isolated directly from ethylene glycol solutions of the barium-copper salt. In this molecule, copper is coordinated to the four xygens of two ethylene glycolate ligands in a nearly square planar geometry. Barium is coordinated by three bidentate ethylene glycol molecules and three monodentate ethylene glycol molecules; the 9-fold coordination resembles a trigonal prism with each rectangular face capped. Copper and barium moieties do not share any ethylene glycol or glycolate oxygens; they are found by hydrogen bonding to form linear chains. The second crystal type has formula BaCu(C 2 H 6 O 2 ) 3 (C 2 H 4 O 2 ) 2 (2). It was prepared via crystallization of the mixed-metal alkoxide from an ethylene glycol/methyl ethyl ketone solution. As for 1, the copper is coordinated to four oxygen atoms of two ethylene glycolate ligands in a nearly square planar arrangement. Barium is 8-coordinate in a distorted cubic geometry. It is coordinated to three bidentate ethylene glycol molecules and shares two of the oxygen atoms bound to the copper (one from each coordinated ethylene glycol) to form a discrete molecular barium-copper complex

Phosphinodi(benzylsilane) PhP{(o-C6H4CH2)SiMe2H}2: a versatile "PSi2Hx" pincer-type ligand at ruthenium.

Science.gov (United States)

Montiel-Palma, Virginia; Muñoz-Hernández, Miguel A; Cuevas-Chávez, Cynthia A; Vendier, Laure; Grellier, Mary; Sabo-Etienne, Sylviane

2013-09-03

The synthesis of the new phosphinodi(benzylsilane) compound PhP{(o-C6H4CH2)SiMe2H}2 (1) is achieved in a one-pot reaction from the corresponding phenylbis(o-tolylphosphine). Compound 1 acts as a pincer-type ligand capable of adopting different coordination modes at Ru through different extents of Si-H bond activation as demonstrated by a combination of X-ray diffraction analysis, density functional theory calculations, and multinuclear NMR spectroscopy. Reaction of 1 with RuH2(H2)2(PCy3)2 (2) yields quantitatively [RuH2{[η(2)-(HSiMe2)-CH2-o-C6H4]2PPh}(PCy3)] (3), a complex stabilized by two rare high order ε-agostic Si-H bonds and involved in terminal hydride/η(2)-Si-H exchange processes. A small free energy of reaction (ΔrG298 = +16.9 kJ mol(-1)) was computed for dihydrogen loss from 3 with concomitant formation of the 16-electron species [RuH{[η(2)-(HSiMe2)-CH2-o-C6H4]PPh[CH2-o-C6H4SiMe2]}(PCy3)] (4). Complex 4 features an unprecedented (29)Si NMR decoalescence process. The dehydrogenation process is fully reversible under standard conditions (1 bar, 298 K).

The K2-138 System: A Near-resonant Chain of Five Sub-Neptune Planets Discovered by Citizen Scientists

DEFF Research Database (Denmark)

Christiansen, Jessie L.; Crossfield, Ian J. M.; Barentsen, Geert

2018-01-01

K2-138 is a moderately bright (V = 12.2, K = 10.3) main-sequence K star observed in Campaign 12 of the NASA K2 mission. It hosts five small (1.6-3.3 R⊕) transiting planets in a compact architecture. The periods of the five planets are 2.35, 3.56, 5.40, 8.26, and 12.76 days, forming an unbroken...... chain of near 3:2 resonances. Although we do not detect the predicted 2-5 minute transit timing variations (TTVs) with the K2 timing precision, they may be observable by higher-cadence observations with, for example, Spitzer or CHEOPS. The planets are amenable to mass measurement by precision radial...... velocity measurements, and therefore K2-138 could represent a new benchmark system for comparing radial velocity and TTV masses. K2-138 is the first exoplanet discovery by citizen scientists participating in the Exoplanet Explorers project on the Zooniverse platform....

"Plug-and-Play" potentials: Investigating quantum effects in (H2)2-Li+-benzene

Science.gov (United States)

D'Arcy, Jordan H.; Kolmann, Stephen J.; Jordan, Meredith J. T.

2015-08-01

Quantum and anharmonic effects are investigated in (H2)2-Li+-benzene, a model for hydrogen adsorption in metal-organic frameworks and carbon-based materials, using rigid-body diffusion Monte Carlo (RBDMC) simulations. The potential-energy surface (PES) is calculated as a modified Shepard interpolation of M05-2X/6-311+G(2df,p) electronic structure data. The RBDMC simulations yield zero-point energies (ZPE) and probability density histograms that describe the ground-state nuclear wavefunction. Binding a second H2 molecule to the H2-Li+-benzene complex increases the ZPE of the system by 5.6 kJ mol-1 to 17.6 kJ mol-1. This ZPE is 42% of the total electronic binding energy of (H2)2-Li+-benzene and cannot be neglected. Our best estimate of the 0 K binding enthalpy of the second H2 to H2-Li+-benzene is 7.7 kJ mol-1, compared to 12.4 kJ mol-1 for the first H2 molecule. Anharmonicity is found to be even more important when a second (and subsequent) H2 molecule is adsorbed; use of harmonic ZPEs results in significant error in the 0 K binding enthalpy. Probability density histograms reveal that the two H2 molecules are found at larger distance from the Li+ ion and are more confined in the θ coordinate than in H2-Li+-benzene. They also show that both H2 molecules are delocalized in the azimuthal coordinate, ϕ. That is, adding a second H2 molecule is insufficient to localize the wavefunction in ϕ. Two fragment-based (H2)2-Li+-benzene PESs are developed. These use a modified Shepard interpolation for the Li+-benzene and H2-Li+-benzene fragments, and either modified Shepard interpolation or a cubic spline to model the H2-H2 interaction. Because of the neglect of three-body H2, H2, Li+ terms, both fragment PESs lead to overbinding of the second H2 molecule by 1.5 kJ mol-1. Probability density histograms, however, indicate that the wavefunctions for the two H2 molecules are effectively identical on the "full" and fragment PESs. This suggests that the 1.5 kJ mol-1 error is

"Plug-and-Play" potentials: Investigating quantum effects in (H2)2-Li(+)-benzene.

Science.gov (United States)

D'Arcy, Jordan H; Kolmann, Stephen J; Jordan, Meredith J T

2015-08-21

Quantum and anharmonic effects are investigated in (H2)2-Li(+)-benzene, a model for hydrogen adsorption in metal-organic frameworks and carbon-based materials, using rigid-body diffusion Monte Carlo (RBDMC) simulations. The potential-energy surface (PES) is calculated as a modified Shepard interpolation of M05-2X/6-311+G(2df,p) electronic structure data. The RBDMC simulations yield zero-point energies (ZPE) and probability density histograms that describe the ground-state nuclear wavefunction. Binding a second H2 molecule to the H2-Li(+)-benzene complex increases the ZPE of the system by 5.6 kJ mol(-1) to 17.6 kJ mol(-1). This ZPE is 42% of the total electronic binding energy of (H2)2-Li(+)-benzene and cannot be neglected. Our best estimate of the 0 K binding enthalpy of the second H2 to H2-Li(+)-benzene is 7.7 kJ mol(-1), compared to 12.4 kJ mol(-1) for the first H2 molecule. Anharmonicity is found to be even more important when a second (and subsequent) H2 molecule is adsorbed; use of harmonic ZPEs results in significant error in the 0 K binding enthalpy. Probability density histograms reveal that the two H2 molecules are found at larger distance from the Li(+) ion and are more confined in the θ coordinate than in H2-Li(+)-benzene. They also show that both H2 molecules are delocalized in the azimuthal coordinate, ϕ. That is, adding a second H2 molecule is insufficient to localize the wavefunction in ϕ. Two fragment-based (H2)2-Li(+)-benzene PESs are developed. These use a modified Shepard interpolation for the Li(+)-benzene and H2-Li(+)-benzene fragments, and either modified Shepard interpolation or a cubic spline to model the H2-H2 interaction. Because of the neglect of three-body H2, H2, Li(+) terms, both fragment PESs lead to overbinding of the second H2 molecule by 1.5 kJ mol(-1). Probability density histograms, however, indicate that the wavefunctions for the two H2 molecules are effectively identical on the "full" and fragment PESs. This suggests that

PHF13 is a molecular reader and transcriptional co-regulator of H3K4me2/3