bluuebunny/crossref_metadata_2025 huggingface dataset:
Improved initial epitaxial growth of β‐FeSi2 on Si(111) substrate by Al‐doping
Authors: Hashimoto Syoutaro , Terai Yoshikazu , Fujiwara Yasufumi
Published: May 2008

Effects of Al‐doping on the iron silicide growth were investigated in reactive deposition epitaxy (RDE) on Si(111) substrates. ε‐FeSi(111) layer was grown on the Si(111) substrate when the Fe of 50 Å was deposited at 750 °C. In Al‐doped samples grown by co‐deposition of Fe and Al, both the crystal orientation of ε‐FeSi(111)//Si(111) and the surface flatness of the layer were improved with increasing Kundsen‐cell temperature of Al (TAl). The highly‐oriented ε‐FeSi templates were annealed at 850 °C for a phase transition from ε‐FeSi to β‐FeSi2. X‐ray diffraction (XRD) measurements of the annealed samples showed that the crystal orientation of β‐FeSi2(202)(220)//Si(111) strongly depended on that of the ε‐FeSi//Si. In undoped samples, XRD peaks originating from polycrystalline β‐FeSi2 were observed in 2θ scan measurements. On the other hand, the peak intensities from the β‐FeSi2 polycrystal became much small in the Al‐doped β‐FeSi2 grown at TAl = 925 °C. These results revealed that Al‐doping during the RDE growth promotes the epitaxial growth of ε‐FeSi(111)//Si(111) and the crystallographic orientation relationship between ε‐FeSi and Si affects the epitaxial growth of β‐FeSi2(101)(110) on Si(111) by the post‐annealing. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Laser‐induced formation of nonradiative centers observed by two‐wavelength excited photoluminescence
Authors: Ogawa H. , Uchiyama N. , Kamata N. , Arakawa Y.
Published: May 2008

By observing an intensity change of photoluminescence (PL) due to the addition of a below‐gap excitation light (BGE effect), a quantitative determination of nonradiative recombination (NRR) centers becomes possible. We observed an irreversible decrease of the BGE effect, together with a distinct PL quenching, when a GaN/AlGaN quantum well was irradiated by a Nd:YAG laser (1.17 eV) in addition to a D2 lamp (4.88 eV). The decrease is considered to be due to the formation of a NRR center at sample surface. An equivalent rate equation analysis explained both of the experimental change rather well. The observation of a defect formation enables us to understand the nature of NRR centers more dynamically, thus it is effective for determining the origin of the defect and optimizing the growth condition in nitride‐based materials. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Electro‐optic property of ZnO:Mn epitaxial films
Authors: Oshio T. , Masuko K. , Ashida A. , Yoshimura T. , Fujimura N.
Published: May 2008

Mn doping effect on the dielectric and electro‐optic (E‐O) property of ZnO epitaxial films was studied. The leakage current of the ZnO film is drastically decreased by doping Mn with the concentration of 3‐5 at%. Although, ZnO: 4 at% Mn with the lowest leakage current has the largest frequency dispersion of birefringence shift (Δ n) at 1 kHz, and its E‐O coefficient (rc) was larger than that of ZnO single crystal. It is presumably caused by another polarization effect but spontaneous polarization, such as space charge. To investigate the origin of the dispersion of Δ n, discharging property was evaluated. When the signal at 1 kHz was applied, ZnO: 3 and 5 at% Mn showed the discharging with relaxation time of 5 msec. Furthermore, the discharging property with same relaxation time was observed at 20 kHz at where the dispersion of Δ n was not observed. However, ZnO: 4 at% Mn does not show such a discharging behavior. Therefore, it is considered that the space charge is not the origin of the dispersion of Δ n. On the other hand, the dispersion of Δ n was minimum and no dielectric dispersion was observed at 20 kHz for all samples. The rc of ZnO: 3, 4 and 5 at% Mn measured at 20 kHz, which should be the rc originated from the spontaneous dipolar polarization, were derived to be 0.81, 0.81 and 0.62 pm/V, respectively. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Trap states in n‐GaN grown on AlN/sapphire template by MOVPE
Authors: Ito T. , Yoshikawa M. , Watanabe A. , Egawa T.
Published: May 2008

Using epitaxial AlN/sapphire templates, high crystalline quality GaN films are grown on them by metal organic chemical vapour deposition. The electron traps behaviour of these GaN films were observed by deep level transient spectroscopy (DLTS). Four distinct trap levels were ob‐served in both n‐GaN grown on AlN/sapphire template and on conventional low temperature buffer layer (LT‐BL)/sapphire. The magnitude the of the DLTS signal E1 and E2 were almost same. It suggests that E1 is not only associate with dislocation density but also other defect. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication of blue‐shifted Fabry‐Perot laser diodes for integration with optical passive waveguides
Authors: Byun Young Tae , Kim Suhyun , Kim Sun Ho , Chung Youngchul
Published: May 2008

Laser diodes monolithically integrated with a passive waveguide is fabricated by using a quantum‐well intermixing. This technique first consists of using a photolithography and reactive ion etching process to create a Si3N4 implant mask region on the sample. This is followed by a 1‐MeV phosphorous ion implantation at a dose of 5×1014 P+ ions/cm2 at 200 °C. A subsequent two‐step RTA annealing induces QW intermixing through the diffusion of the point defects. For the integration of a laser diode and a passive waveguide, the mirror facet is formed by creating a deeply‐etched trench between an active and passive region by RIE etching. The lasing operation and shifted lasing wavelengths are measured and compared experimentally. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Energy dependent carrier relaxation in self‐assembled InAs/GaAs quantum dots
Authors: Ling H. S. , Lee C. P. , Wang S. Y. , Lo M. C.
Published: May 2008

We performed the selective excitation photoluminescence (SEPL) spectroscopy studies on InAs/GaAs self‐assembled quantum dots (QDs). Under different excitation energies, different groups of QDs are selected and emit light. The excited carriers relax to the ground state through different mechanisms when excited at different energies. Three distinct regions with different mechanisms in carrier excitation and relaxation are identified in the emission spectra. These three regions can be categorized, from high energy to low energy, as continuum absorption, electronic state excitation, and multi‐phonon resonance. The QDs' special joint density‐of‐state tail extending from the wetting layer peak facilitates the carrier relaxation and was suggested to explain these spectral results. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
GaAs area‐selective regrowth with molecular layer epitaxy for integration of low noise and power transistors, and Schottky diodes
Authors: Nishizawa J. , Płotka P. , Kurabayashi T.
Published: May 2008

We have developed a GaAs mm‐wave power static induction transistor (SIT) with a regrown source‐drain offset. It was fabricated with low‐temperature, area‐selective molecular layer epitaxial regrowth in a process compatible with that of a low‐noise high‐frequency ideal static induction transistor. The fmax of the power SIT was 111 GHz at gm of 220 mS/mm. These values can be improved with gate engineering. Our method can be used for fabrication of mm‐wave system‐on‐chip wafers including also Schottky barrier diodes. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth and characterization of GaSb heteroepitaxial layers on Si(111) substrates
Authors: Toyota H. , Yasuda T. , Endoh T. , Jinbo Y. , Uchitomi N.
Published: May 2008

We investigated the growth of GaSb layers and GaSb/‐AlGaSb multiple quantum well (MQW) structures using an AlSb initiation layer on Si(111) substrates. The entire growth was monitored using reflection high‐energy electron diffraction (RHEED). The GaSb epitaxial films and MQWstructures were characterized by X‐ray diffraction (HRXRD), atomic force microscopy (AFM) and photoluminescence (PL) spectroscopy.

Our results suggest that high‐quality (111)‐oriented GaSb films with a mirror surface can be obtained using the present growth condition. The PL peak energy of the MQWs on Si(111) substrates is almost temperature independent up to ∼120 K and exhibits relatively smaller variation with temperature compared to that of the MQWs grown on Si(001) substrates. (© 2008 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Study of energetics of end‐on and side‐on peroxide coordination in ligated Cu2O2 models with State‐Specific Equation of Motion Coupled Cluster Method
Authors: Kong Liguo , Nooijen Marcel
Published: May 2008

Newly developed State‐Specific Equation of Motion Coupled Cluster method (SS‐EOMCC) is used to study the relative energetics of μ‐1:2(trans end‐on) and μ‐η2:η2(side‐on) peroxo isomers of Cu2O2 fragments with 0 and 2 ammonia ligands. These model systems had been shown to be problematic to multireference perturbation theory (MRPT) and density functional theory (DFT) methods. In spite of the small reference space used, SS‐EOMCC gives much improved results by comparison to benchmark CR‐CC results. In addition to the fully symmetric 1Ag state, 1Bg and 3Bg states are also computed, demonstrating the complexity of the systems under study, as seen from the energy crossing at intermediate geometries. Spin‐flip idea is natural in our current theoretical framework and is tried for the model systems. It is argued that an important feature of the SS‐EOMCC method is that orbitals are optimized in the presence of dynamical correlation. This is the prime reason that a very small set of active orbitals can be used to achieve satisfactory results. © 2008 Wiley Periodicals, Inc. Int J Quantum Chem, 2008
Real options and real value: the role of employee incentives to make specific knowledge investments
Authors: Wang Heli , Lim Sonya Seongyeon
Published: May 2008

Real options reasoning emphasizes the strategic value of making flexible investments in a turbulent environment. Employees' investments in specific human capital are often critical to the success of a real option project, but the very flexibility that allows a firm to change course in response to new information also affects employees' incentives to make such specific human capital investments. We develop a model of real option investment that explicitly incorporates the role of employee incentives. The model suggests that the effect of investing in a real option project on employee incentives may be positive, further increasing the value of the project, or negative, sometimes more than offsetting the benefit of flexibility and resulting in reduced project value. Therefore, firms and managers should take into consideration the role of employee incentives when applying real options logic to investment decision making. Copyright © 2008 John Wiley & Sons, Ltd.
7‐Nitroindazole, nitric oxide synthase inhibitor, attenuates physical dependence on butorphanol in rat
Authors: Tian Yu‐Hua , Lee Kwang‐Wook , You In‐Jee , Lee Seok‐Yong , Jang Choon‐Gon
Published: May 2008

Butorphanol is a synthetic opioid agonist/antagonist analgesic agent that mainly exerts its effects through κ‐opioid receptors. It has been demonstrated that κ‐opioid receptors preferentially mediate the development of physical dependence upon butorphanol and the associated withdrawal syndrome. However, it is not fully understood whether or not nNOS‐containing neurons in the various brain regions play an important role in butorphanol withdrawal. Therefore, this study was conducted to determine whether the selective nNOS inhibitor, 7‐NI, modifies the development of butorphanol withdrawal and changes of nNOS expressions in different brain regions in physically butorphanol‐dependent rats. The first part of the study focused on withdrawal behaviors in male Sprague‐Dawley rats. Physical dependence was induced by a 72‐h i.c.v. infusion with butorphanol (26 nmol/μl/h) and withdrawal was subsequently precipitated by i.c.v. challenge with naloxone (48 nmol/5 μl/rat) 2 h after termination of the butorphanol infusion. The butorphanol/7‐NI coadministration group showed a significant decrease in several signs of withdrawal such as teeth chattering, as compared with the butorphanol‐treated group. In the second part of the study, immunohistochemical analysis was performed to determine the expression of nNOS in the various brain regions. In the butorphanol/7‐NI coadministration group, the number of cells labeled for nNOS was significantly lower in the various brain regions (including the caudate putamen, nucleus accumbens, and hippocampus) than in the butorphanol group. Therefore, 7‐NI decreased in butorphanol‐induced physical dependence and nNOS expression. Taken together, these findings suggest that the nNOS system is involved in the development of butorphanol‐induced physical dependence, and 7‐NI has potential clinical application as a candidate for the treatment of opioid withdrawal syndrome. Synapse 62:582–589, 2008. © 2008 Wiley‐Liss, Inc.
Azidokomplexe von Vanadium(IV) und Vanadium(V): (Ph4P)2[VOCl2(μ‐N3)]2 und (Ph4P)2[VOCl(μ‐N3)(N3)2]2
Authors: Burghaus Olaf , Neumüller Bernhard , Dehnicke Kurt
Published: May 2008

Azido Complexes of Vanadium(IV) and Vanadium(V): (Ph4P)2[VOCl2(μ‐N3)]2 and (Ph4P)2[VOCl(μ‐N3)(N3)2]2

(Ph4P)2[VOCl2(μ‐N3)]2 (1) was prepared by reaction of (Ph4P)[VO2Cl2] with trimethylsilylazide in the molar ratio 1:2 in dichloromethane solution to give dark green, moisture sensitive, non‐explosive single crystals. The reaction is accompanied by the formation of the dark blue side‐product (Ph4P)2[VOCl(μ‐N3)(N3)2]2 (2a), which can be obtained as the main product by application of a large excess of Me3SiN3. Dark blue needles of 2a crystallize spontaneously from the CH2Cl2 solution within one hour at 4 °C. After standing at 4 °C under its mother liquid within 24 hours a first‐order phase transition of 2a occurs forming dark blue prismatic single crystals of 2b. According to single crystal X‐ray structure determinations, 2a and 2b crystallize in the same type of space group $\rm P{\bar 1}$, however, with different lattice dimensions.

The vanadium(IV) complex 1 is characterized by X‐ray structure determination and by vibrational spectroscopy (IR, Raman) as well as by EPR spectroscopy, whereas 2b is characterized by IR spectroscopy.

1: Space group P21/n, Z = 2, a = 1009.5(1), b = 1226.6(2), c = 1943.0(2) pm, β = 98.42(1)°, R1 = 0.0672. The complex anion $\rm [VOCl_{2}(\mu-N_{3})]^{2-}_{{2}/{2}}$ forms centrosymmetric units with V2N2‐four‐membered rings with a V···V distance of 335.6(1) pm and coordination number five on the vanadium(IV) atoms.

2a: Space group $\rm P{\bar 1}$, Z = 1, a = 1089.0(2), b = 1097.1(2), c = 1310.1(2) pm, α = 92.99(1)°, β = 106.12(2)°, γ = 117.05(2)°, V = 1309.8(4) Å3, dcalc. = 1.440 g·cm−3, R1 = 0.0384. The complex anion forms centrosymmetric units of symmetry Ci with V2N2 four‐membered rings and VN bond lengths of 200.4(3) and 234.4(2) pm, respectively. The non‐bonding V···V distance amounts to 356.2(1) pm.

2b: Space group $\rm P{\bar 1}$, Z = 1, a = 1037.3(2), b = 1157.6(2), c = 1177.2(2) pm, α = 98.48(2)°, ° = 103.82(2)°, γ = 106.33(2)°, V = 1281.8(4) Å3, dcalc. = 1.471 g·cm−3, R1 = 0.0724. The structure of the complex anion $\rm [VOCl(\mu-N_{3})(N_{3})_{2}]^{2-}_{{2}/{2}}$ is similar to the anion of 2a with VN bond lengths of the four‐membered V2N2 ring of 203.3(4) and 235.2(4) pm, respectively, and a non‐bonding V···V distance of 357.5(1) pm.
Building the “Phosphoindigo” Backbone by Oxidative Coupling of Phosphindolin‐3‐ones with Selenium Dioxide
Authors: Vollbrecht Sebastian , Dobreva Guergana , Cartis Ioana , du Mont Wolf‐W. , Jeske Jörg , Ruthe Frank , Jones Peter G. , Ernst Ludger , Grahn Walter , Papke Ulrich , Marzini Michael , Mayer Hermann A.
Published: May 2008

Oxidative coupling of racemic 1‐ethoxy‐1‐oxophosphindolin‐3‐one (1) and its 5‐CF3‐derivative 6 with SeO2 furnishes 1,1′‐diphosphaindigo derivatives 5 and 7 as bis‐phosphinic esters, i. e. as PV‐compounds. Like indigo and thioindigo, 5 and 7 exist in the E‐configuration; the crude products of 5 and 7 are mixtures of isomers that are trans‐ and cis‐configurated with respect to the relative orientation of the ester groups oat phosphorus. The structure of the centrosymmetric E‐P(R)P′(S) isomer [(E)‐trans‐isomer] of 5 was determined by X‐ray crystallography. Ester cleavage of 5, followed by addition of triethylamine to bis‐phosphinic acid 9 (the 1,1,1′,1′‐tetroxide of “phosphoindigo”), furnishes the related bis‐triethylammonium salt 10 as a crystalline hydrate that exhibits an extended hydrogen bonding network.
Addition von kationischen Lewis‐Säuren [M′Ln]+ (M′Ln = Fe(CO)2Cp, Fe(CO)(PPh3)Cp, Ru(PPh3)2Cp, Re(CO)5, ${1 \over 2}$ Pt(PPh3)2, W(CO)3Cp an die anionischen Thiocarbonyl‐Komplexe [HB(pz)3(OC)2M(CS)]− (M = Mo, W; pz = 3,5‐dimethylpyrazol‐1‐yl)
Authors: Knauer Wolfgang , Beck Wolfgang
Published: May 2008

Addition of Cationic Lewis Acids [M′Ln]+ (M′Ln = Fe(CO)2Cp, Fe(CO)(PPh3)Cp, Ru(PPh3)2Cp, Re(CO)5, ${1 \over 2}$ Pt(PPh3)2, W(CO)3Cp to the Anionic Thiocarbonyl Complexes [HB(pz)3(OC)2M(CS)]− (M = Mo, W; pz = 3,5‐dimethylpyrazol‐1‐yl)

Adducts from Organometallic Lewis Acids [Fe(CO)2Cp]+, [Fe(CO)(PPh3)Cp]+, [Ru(PPh3)2Cp]+, [Re(CO)5]+, [${1 \over 2}$ Pt(PPh3)2]+, [W(CO)3Cp]+ and the anionic thiocarbonyl complexes [HB(pz)3(OC)2M(CS)]− (M = Mo, W) have been prepared. Their spectroscopic data indicate that the addition of the cations occurs at the sulphur atom to give end‐to‐end thiocarbonyl bridged complexes [HB(pz)3(OC)2MCSM′Ln].
Magnetic, Optical, and Electronic Properties of the Phosphide Oxides REZnPO (RE = Y, La–Nd, Sm, Gd, Dy, Ho)
Authors: Lincke Hannes , Glaum Robert , Dittrich Volker , Tegel Marcus , Johrendt Dirk , Hermes Wilfried , Möller Manfred H. , Nilges Tom , Pöttgen Rainer
Published: May 2008

Well‐shaped yellow to red transparent single crystals of the phosphide oxides REZnPO (RE = Y, La–Nd, Sm, Gd, Dy, Ho) were synthesized from the elements and ZnO in NaCl/KCl fluxes in sealed silica ampoules. Four structures (NdZnPO type, R3m) were refined from single crystal X‐ray diffractometer data: a = 388.5(2), c = 3032(1) pm, wR2 = 0.0380, 360 F2 values for YZnPO, a = 394.6(2), c = 3071(1) pm, wR2 = 0.0587, 226 F2 values for SmZnPO, a = 392.2(2), c = 3056(1) pm, wR2 = 0.0262, 462 F2 values for GdZnPO, and a = 389.33(6), c = 3030.5(4) pm, wR2 = 0.0453, 217 F2 values for DyZnPO each with 14 variables per refinement. The structures are composed of alternate stacks of (RE3+O2−) and (Zn2+P3−) layers with covalent RE–O and ZñP bonding within and weak ionic bonding between the layers. The zinc and oxygen atoms have slightly distorted tetrahedral coordination by atoms of phosphorus and the rare earth element, respectively. According to the electron precise formulation RE3+Zn2+P3−O2−, these pnictide oxides are transparent in visible light. Susceptibility measurements on β‐CeZnPO, β‐PrZnPO, and GdZnPO reveal Curie‐Weiss paramagnetism with experimental magnetic moments of 2.31, 3.60, and 7.72 μB/RE atoms, respectively. β‐CeZnPO and β‐PrZnPO show antiferromagnetic order with Néel temperatures of 7.4 (Ce) and 2.2 (Pr) K. GdZnPO shows no magnetic ordering down to 2 K. Single crystal absorption spectra measured for REZnPO (RE = Y, La, Pr, Nd, Sm, Dy) in the NIR‐Vis region reveal unexpected variations for the optical band gap of these phosphide oxides. For RE = Pr, Nd, Sm, Dy, Ho f‐f electronic transitions with nicely resolved ligand‐field splittings are observed in the range 6000–20000 cm−1. DFT band structure calculations show similarity between the valence bands of tetragonal and rhombohedral REZnPO as they possess mainly P‐3p character. In both cases, the conduction bands have mainly Zn‐4s character, but a significant contribution of RE‐5d occurs in rhombohedral REZnPO, which is responsible for a smaller optical band gap for the latter compounds. Variations of the energy gaps of tetragonal REZnPO can be explained by hybridization of Zn‐4s + RE‐5d + RE‐4f orbitals for the conduction band. DFT volume optimizations of α‐ and β‐PrZnPO show β‐PrZnPO to be more stable by 10.7 kJ mol−1.
Crystal and Molecular Structure of trans‐[IrCl(N2)(PiPr3)2]
Authors: Böttcher Hans‐Christian , Graf Marion , Mayer Peter , Sünkel Karlheinz
Published: May 2008

Single crystals of trans‐[IrCl(N2)(PiPr3)2] (1), obtained during studies on the reaction of [{Ir(μ‐Cl)(coe)2}2] (coe = cis‐cyclooctene) with tri‐iso‐propylphosphane in diethyl ether under dinitrogen atmosphere, have been analyzed by X‐ray crystallography (monoclinic, P21/c, Z = 2, a = 8.0855(9), b = 8.896(3), c = 16.539(3) Å; β = 93.124(11)°; V = 1187.9(4); T = 200(2) K). In the course of these studies under an atmosphere of dinitrogen or argon, the formation of a variety of phosphorus‐containing compounds was indicated using 31P{1H} NMR spectroscopy.
Komplexe mit Antimon‐Liganden: [tBu2(Cl)SbW(CO)5], [tBu2(OH)SbW(CO)5], O[SbPh2W(CO)5]2, E[SbMe2W(CO)5]2 (E = Se, Te), cis‐[(Me2SbSeSbMe2)2Cr(CO)4]
Authors: Breunig H. J. , Lork E. , Moldovan O. , Wagner R.
Published: May 2008

Complexes Containing Antimony Ligands: [tBu2(Cl)SbW(CO)5], [tBu2(OH)SbW(CO)5], O[SbPh2W(CO)5]2, E[SbMe2W(CO)5]2 (E = Se, Te), cis‐[(Me2SbSeSbMe2)2Cr(CO)4]

Syntheses of [tBu2(Cl)SbW(CO)5] (1), [tBu2(OH)SbW(CO)5] (2), O[SbPh2W(CO)5]2 (3), Se[SbMe2W(CO)5]2 (4), cis‐[(Me2SbSeSbMe2)2Cr(CO)4] (5) Te[SbMe2W(CO)5]2 (6) and crystal structures of 1–5 are reported.
Isolated Triiodide and Pentaiodide Anions in the Crystal Structure of [Rb(Dibenzopyridino‐18‐Crown‐6)2]2(I3)(I5)
Authors: Walbaum Christine , Pantenburg Ingo , Meyer Gerd
Published: May 2008

Red shiny crystals of [Rb(dibenzopyridino‐18‐crown‐6)2]2(I3)(I5) were obtained from a dichloromethane/ethanol solution of RbI, I2 and dibenzopyridino‐18‐crown‐6. Triclinic, $\rm P{\bar 1}$, a = 1494.3(1), b = 1534.1(1), c = 2412.9(2) pm, α = 76.95(1), β = 83.58(1), γ = 68.67(1)°, V = 5016.7(7) 106·pm3, Z = 2. The crystal structure consists of [Rb(dbp18c6)2]+ cations leaving suitable three‐dimensional channels for the linear I3− and V‐shaped I5− anions which are isolated from each other.
Abbau von Koordinationspolymeren bis zum Monomer und Konkurrenz von Polymerisation und Chemischer Schere an Carbazolaten von Yb und Eu mit N‐Phenylpiperazin
Authors: Zurawski Alexander , Müller‐Buschbaum Klaus
Published: May 2008

Degradation of Coordination Polymers to the Monomer and Competition of Polymerization and Chemical Scissors on Carbazolates of Yb and Eu with N‐Phenylpiperazine

The coordination polymers $^{1}_{\infty}\rm [Ln_{2}(Cbz)_{4}]$, Ln = Yb, Eu, Cbz− = carbazolate anion, C12H8N−, can be degraded by the use of strong N‐donor ligands like N‐phenylpiperazine (Phpip = (C6H5)C4H8NNH) as chemical scissors. The degradation process for the ytterbium containing polymer ends in the monomeric compound [Yb(Cbz)3(Phpip)2]·1/2Phpip and includes an oxidation step YbII → YbIII. Thus the circle of reactions of Yb metal with carbazole (CbzH) starting in liquid NH3 to the coordination polymer and ending with its degradation by the use of chemical scissors is resolved. Transformation on europium has been started on the base of both metals leading to coordination polymers of the same chemical formula. However already the prelude of reactions differs for Eu as the electride induced reaction of Eu metal with CbzH in liquid ammonia followed by Phpip treatment gives single crystalline [Eu2(Cbz)4(NH3)2(Phpip)4]·2Phpip. This dimeric molecule contains EuII and ligands of all reaction steps, NH3, Cbz−, Phpip, and is thereby an interesting starting point for the resolution of polymer formation and degradation as well as a competition of these counter reactions.
Ferrocene Derivatives Bearing one and two Isocyanato, Isothiocyanato and Isoselenocyanato Substituents
Authors: Wrackmeyer Bernd , Maisel Heidi E. , Milius Wolfgang , Herberhold Max
Published: May 2008

Isocyanato‐ (1a), 1,1′‐di(isocyanato)‐ (2a), isothiocyanato‐ (1b), 1,1′‐di(isothiocyanato)‐ (2b), isoselenocyanato‐ (1c) and 1,1′‐di(isoselenocyanato)ferrocene (2c) were prepared and studied by 1H, 13C and 14N NMR spectroscopy. Isocyanatoferrocene (1a) trimerizes upon chromatography on alumina to give 3a. The molecular structures of 2c and 3a were determined by X‐ray analysis, and almost undistorted ferrocene‐like structures were found in both cases.
Fatty Acid Profile of Sunshine Bass: II. Profile Change Differs Among Fillet Lipid Classes
Authors: Trushenski Jesse T. , Lewis Heidi A. , Kohler Christopher C.
Published: May 2008

Fatty acid (FA) profile of fish tissue mirrors dietary FA profile and changes in a time‐dependent manner following a change in dietary FA composition. To determine whether FA profile change varies among lipid classes, we evaluated the FA composition of fillet cholesteryl esters (CE), phospholipids (PL), and triacylglycerols (TAG) of sunshine bass (SB, Morone chrysops × M. saxatilis) raised on feeds containing fish oil or 50:50 blend of fish oil and coconut, grapeseed, linseed, or poultry oil, with or without implementation of a finishing period (100% FO feed) prior to harvest. Each lipid class was associated with a generalized FA signature, irrespective of nutritional history: fillet PL was comprised largely of saturated FA (SFA), long‐chain polyunsaturated FA (LC‐PUFA), and total n‐3 FA; fillet TAG was higher in MC‐PUFA and total n‐6 FA; and fillet CE was highest in monounsaturated FA (MUFA). Neutral lipids reflected dietary composition in a near‐direct fashion; conversely, PL showed evidence of selectivity for MC‐ and LC‐PUFA. Shorter‐chain SFA were not strongly reflected within any lipid fraction, even when dietary availability was high, suggesting catabolism of these FA. FA metabolism in SB is apparently characterized by a division between saturated and unsaturated FA, whereby LC‐PUFA are preferentially incorporated into tissues and SFA are preferentially oxidized for energy production. We demonstrated provision of SFA in grow‐out feeds for SB, instead MC‐PUFA which compete for tissue deposition, meets energy demands and allows for maximum inclusion of LC‐PUFA within fillet lipids.
Cognitive and mood effects in healthy children during 12 weeks' supplementation with multi-vitamin/minerals
Authors: Haskell Crystal F. , Scholey Andrew B. , Jackson Philippa A. , Elliott Jade M. , Defeyter Margaret A. , Greer Joanna , Robertson Bernadette C. , Buchanan Tom , Tiplady Brian , Kennedy David O.
Published: May 2008

Adequate levels of vitamins and minerals are essential for optimal neural functioning. A high proportion of individuals, including children, suffer from deficiencies in one or more vitamins or minerals. This study investigated whether daily supplementation with vitamins/minerals could modulate cognitive performance and mood in healthy children. In this randomised, double-blind, placebo-controlled, parallel groups investigation, eighty-one healthy children aged from 8 to 14 years underwent laboratory assessments of their cognitive performance and mood pre-dose and at 1 and 3 h post-dose on the first and last days of 12 weeks' supplementation with a commercially available vitamins/mineral product (Pharmaton Kiddi™). Interim assessments were also completed at home after 4 and 8 weeks at 3 h post-dose. Each assessment comprised completion of a cognitive battery, delivered over the Internet, which included tasks assessing mood and the speed and accuracy of attention and aspects of memory (secondary, semantic and spatial working memory). The vitamin/mineral group performed more accurately on two attention tasks: ‘Arrows’ choice reaction time task at 4 and 8 weeks; ‘Arrow Flankers’ choice reaction time task at 4, 8 and 12 weeks. A single task outcome (Picture Recognition errors) evinced significant decrements at 12 weeks. Mood was not modulated in any interpretable manner. Whilst it is possible that the significant improvements following treatment were due to non-significant numerical differences in performance at baseline, these results would seem to suggest that vitamin/mineral supplementation has the potential to improve brain function in healthy children. This proposition requires further investigation.
TWENTY YEARS’ DEMOGRAPHIC CHANGE IN SEDENTES AND MIGRANTS OF AN INTERNATIONAL MIGRANT-SENDING COMMUNITY IN TONGA
Authors: FUKUYAMA SHOKO , WATANABE CHIHO , UMEZAKI MASAHIRO , OHTSUKA RYUTARO
Published: May 2008

In the Kingdom of Tonga, migration to overseas developed countries has prevailed. To elucidate the effects of migration on population dynamics, an interview survey was conducted in the migrant-sending community of Kolovai, in the outer region of Tongatapu Island. All births, deaths, marriages and in- and out-migrations that took place between 1983 and 2002 were recorded for all members of the ‘Kolovai population’, consisting of persons who had lived in this community for at least a one-year period during this 20 years. The ‘Kolovai population’ members, numbering 1184 (564 males and 620 females), were divided into three groups based on residence at the end of each year, i.e. Kolovai (called KK), other places in Tonga (KT) or overseas countries (KO). The KK population decreased from 774 in 1982 to 570 in 2002, owing mostly to an increase of 167 persons as the natural balance and a decrease of 324 persons as the balance of international migration. Comparison of total fertility rate (TFR) between KK and KO women revealed that the mean TFR of the former decreased from 3·460 in the earlier 10-year period (1983–1992) to 2·240 in the later 10-year period (1993–2002), while that of the latter was more than 3·5 in both 10-year periods. This difference was largely due to the decrease in the proportion married among KK women. If the current trends of international migration and fertility continue, the population of Kolovai will be reduced and its age composition will become cylinder-shaped in the near future.
Failure to deactivate in the prefrontal cortex in schizophrenia: dysfunction of the default mode network?
Authors: Pomarol-Clotet E. , Salvador R. , Sarró S. , Gomar J. , Vila F. , Martínez Á. , Guerrero A. , Ortiz-Gil J. , Sans-Sansa B. , Capdevila A. , Cebamanos J. M. , McKenna P. J.
Published: May 2008

Background

Functional imaging studies using working memory tasks have documented both prefrontal cortex (PFC) hypo- and hyperactivation in schizophrenia. However, these studies have often failed to consider the potential role of task-related deactivation.

Method

Thirty-two patients with chronic schizophrenia and 32 age- and sex-matched normal controls underwent functional magnetic resonance imaging (fMRI) scanning while performing baseline, 1-back and 2-back versions of the n-back task. Linear models were used to obtain maps of activations and deactivations in the groups.

Results

The controls showed activation in the expected frontal regions. There were also clusters of deactivation, particularly in the anterior cingulate/ventromedial PFC and the posterior cingulate cortex/precuneus. Compared to the controls, the schizophrenic patients showed reduced activation in the right dorsolateral prefrontal cortex (DLPFC) and other frontal areas. There was also an area in the anterior cingulate/ventromedial PFC where the patients showed apparently greater activation than the controls. This represented a failure of deactivation in the schizophrenic patients. Failure to activate was a function of the patients' impaired performance on the n-back task, whereas the failure to deactivate was less performance dependent.

Conclusions

Patients with schizophrenia show both failure to activate and failure to deactivate during performance of a working memory task. The area of failure of deactivation is in the anterior prefrontal/anterior cingulate cortex and corresponds to one of the two midline components of the ‘default mode network’ implicated in functions related to maintaining one's sense of self.
Determining language dominance in English–Mandarin bilinguals: Development of a self-report classification tool for clinical use
Authors: LIM VALERIE P. C. , LIOW SUSAN J. RICKARD , LINCOLN MICHELLE , CHAN YIONG HUAK , ONSLOW MARK
Published: May 2008

In multilingual Asian communities, determining language dominance for clinical assessment and intervention is often complex. The aim of this study was to develop a self-report classification tool for identifying the dominant language in English–Mandarin bilinguals. Participants (N = 168) completed a questionnaire on language history and single-word receptive vocabulary tests (Peabody Picture Vocabulary Test type) in both languages. The results of a discriminant analysis on the self-report data revealed a reliable three-way classification into English-dominant, Mandarin-dominant, and balanced bilinguals. The vocabulary scores supported these dominance classifications, whereas the more typical variables such as age of first exposure, years of formal instruction, and years of exposure exerted only a limited influence. The utility of this classification tool in clinical settings is discussed.
Islam as a point of reference for political and social groups in Iraq
Authors: Luizard Pierre-Jean
Published: May 2008

Iraq occupies a special position in the general context of re-Islamization of Arab societies because of the US occupation and the absence of a viable state. The attempt to rebuild communities under the aegis of the United States led to a widespread withdrawal back into communities in which Islam plays a vital role. Sectarian identities were intensified, particularly because they built on layers largely secularized by years of a form of political life that had been partly dominated by secular or secularist parties (Communist Party, Baath party). It looks as if a secularized form of Islam, whose vocation is primarily to confer an identity and which has become impervious to any religious code, is likely to fuel the fighting, which is all the more inexpiable because each person believes that he is fighting for survival as a member of his community.
Justice on hold: accountability and social reconstruction in Iraq
Authors: Stover Eric , Sissons Miranda , Pham Phuong , Vinck Patrick
Published: May 2008

Having invaded Iraq without UN Security Council authorization, the United States was unable to convince many countries to take a meaningful role in helping Iraq deal with its violent past. Always insisting that it would “go it alone”, the United States implemented accountability measures without properly consulting the Iraqi people. Nor did the United States access assistance from the United Nations and international human rights organizations, all of which possess considerable knowledge and experience of a wide range of transitional justice mechanisms. In the end, the accountability measures introduced by the Americans either backfired or were hopelessly flawed. What are needed in Iraq are a secure environment and a legitimate authority to implement a comprehensive transitional justice strategy that reflects the needs and priorities of a wide range of Iraqis. Such a strategy should contain several measures, including prosecutions, reparations, a balanced approach to vetting, truth-seeking mechanisms and institutional reform.
The strategic importance of the Internet for armed insurgent groups in modern warfare
Authors: Adhami Wael
Published: May 2008

In modern times the Internet has become the only tool which can be used to spread information instantaneously and free of charge to anyone in the world who has an Internet connection. The ability to spread information is vital for any party engaged in an armed conflict. This article will show that groups engaged in a jihad have made the Internet their main outlet to the world. It will further examine the content of Islamic and jihadi websites, their main objectives and the communication strategies used. However, and with a particular focus on Iraq, the author will argue that the Internet does not serve as a platform of recruitment for jihad but is rather the most effective way for armed insurgent groups to win the “hearts and minds” of Muslims worldwide.
Assessing the human tragedy in Iraq
Authors: İhsanoğlu Ekmeleddin
Published: May 2008

Before a framework can be set for efforts centred on human security to combat chaos, instability and insecurity in conflict areas, the human tragedy in those areas must be understood and discussed. This article analyses the human tragedy in Iraq and shows that it extends beyond our current perception of the situation. The war has led to the loss of lives and social capital, and has destroyed the Iraqi infrastructure. This substantially lowers the quality of life, leads to the inability to provide essential services and renders state-building activities even more difficult. In line with the policy of the Organisation of the Islamic Conference, the article also emphasizes the need for reconciliation between the various groups in Iraq, an end to sectarian tensions and the preservation of the country's territorial unity as the ultimate resolution of the Iraqi question.
The Kurds as parties to and victims of conflicts in Iraq
Authors: Rogg Inga , Rimscha Hans
Published: May 2008

After decades of fighting and suffering, the Kurds in Iraq have achieved far-reaching self-rule. Looking at the history of conflicts and alliances between the Kurds and their counterparts inside Iraq and beyond its borders, the authors find that the region faces an uncertain future because major issues like the future status of Kirkuk remain unsolved. A federal and democratic Iraq offers a rare opportunity for a peaceful settlement of the Kurdish question in Iraq – and for national reconciliation. While certain groups and currents in Iraq and the wider Arab world have to overcome the notion that federalism equals partition, the Kurds can only dispel fears about their drive for independence if they fully reintegrate into Iraq and show greater commitment to democratic reforms in the Kurdistan Region.
Global estimates of seafloor slope from single‐beam ship soundings
Authors: Becker Joseph J. , Sandwell David T.
Published: May 2008

Rough topography on the ocean floor is a source of ocean mixing which is of interest to both physical oceanography and climate science. Most mixing has been attributed to high slopes of the large‐scale structures of the deep ocean floor such as seamounts, continental margins, and mid‐ocean ridge axes. In this paper, we show the small‐scale but ubiquitous abyssal hills and fracture zones dominate the global map of rough topography. Much of this rugged seafloor occurs in the Southern Ocean on the flanks of the Pacific‐Antarctic Rise and Southwest Indian Ridge. We present our results as a global map of the mean slope of the ocean floor, and as a global map of the ocean floor above theM2 critical slope. We compare our results to multibeam and satellite bathymetry data to show that satellite bathymetry is not a valid proxy for multibeam measurements, but edited single‐beam sonar data are adequate to provide a global perspective on features with horizontal wavelengths as small as 2 km.
Finding concealed active faults: Extending the southern Whidbey Island fault across the Puget Lowland, Washington
Authors: Sherrod Brian L. , Blakely Richard J. , Weaver Craig S. , Kelsey Harvey M. , Barnett Elizabeth , Liberty Lee , Meagher Karen L. , Pape Kristin
Published: May 2008

The southern Whidbey Island fault zone (SWIF), as previously mapped using borehole data, potential field anomalies, and marine seismic reflection surveys, consists of three subparallel, northwest trending strands extending ∼100 km from near Vancouver Island to the northern Puget Lowland. East of Puget Sound, the SWIF makes landfall between the cities of Seattle and Everett but is concealed beneath a thick mantle of young glacial deposits and vegetation. A ∼20‐km‐wide, northwest trending swath of subparallel, low‐amplitude aeromagnetic anomalies crosses this region of the Puget Lowland and is on strike with the SWIF. The most prominent aeromagnetic anomaly, the Cottage Lake lineament, extends at least 18 km and lies approximately on strike with the SWIF on Whidbey Island. Subtle scarps and topographic lineaments on Pleistocene surfaces, visible on high‐resolution lidar topography at a number of locations along the SWIF, lie on or near these magnetic anomalies. In the field, scarps exhibit northeast‐side‐up and vertical relief of 1 to 5 m. Excavations across several lidar scarps lying on or near magnetic anomalies show evidence for multiple folding and faulting events since deglaciation, most likely above buried reverse/oblique faults. Excavations in areas away from magnetic anomalies do not show evidence of tectonic deformation. In total, paleoseismological evidence suggests that the SWIF produced at least four earthquakes since deglaciation about 16,400 years ago, the most recent less than 2700 years ago.
Impact of bending related faulting on the seismic properties of the incoming oceanic plate offshore of Nicaragua
Authors: Ivandic Monika , Grevemeyer Ingo , Berhorst Arnim , Flueh Ernst R. , McIntosh Kirk
Published: May 2008

A seismic wide‐angle and refraction experiment was conducted offshore of Nicaragua in the Middle American Trench to investigate the impact of bending‐related normal faulting on the seismic properties of the oceanic lithosphere prior to subduction. On the basis of the reflectivity pattern of multichannel seismic reflection (MCS) data it has been suggested that bending‐related faulting facilitates hydration and serpentinization of the incoming oceanic lithosphere. Seismic wide‐angle and refraction data were collected along a transect which extends from the outer rise region not yet affected by subduction into the trench northwest of the Nicoya Peninsula, where multibeam bathymetric data show prominent normal faults on the seaward trench slope. A tomographic joint inversion of seismic refraction and wide‐angle reflection data yield anomalously low seismic P wave velocities in the crust and uppermost mantle seaward of the trench axis. Crustal velocities are reduced by 0.2–0.5 km s−1 compared to normal mature oceanic crust. Seismic velocities of the uppermost mantle are 7.6–7.8 km s−1 and hence 5–7% lower than the typical velocity of mantle peridotite. These systematic changes in P wave velocity from the outer rise toward the trench axis indicate an evolutionary process in the subducting slab consistent with percolation of seawater through the faulted and fractured lithosphere and serpentinization of mantle peridotites. If hydration is indeed affecting the seismic properties of the mantle, serpentinization might be reaching 12–17% in the uppermost 3–4 km of the mantle, depending on the unknown degree of fracturing and its impact on the elastic properties of the subducting lithosphere.
Role of precipitation uncertainty in the estimation of hydrologic soil properties using remotely sensed soil moisture in a semiarid environment
Authors: Peters‐Lidard Christa D. , Mocko David M. , Garcia Matthew , Santanello Joseph A. , Tischler Michael A. , Moran M. Susan , Wu Yihua
Published: May 2008

The focus of this study is on the role of precipitation uncertainty in the estimation of soil texture and soil hydraulic properties for application to land‐atmosphere modeling systems. This work extends a recent study by Santanello et al. (2007) in which it was shown that soil texture and related physical parameters may be estimated using a combination of multitemporal microwave remote sensing, land surface modeling, and parameter estimation methods. As in the previous study, the NASA‐GSFC Land Information System modeling framework, including the community Noah land surface model constrained with pedotransfer functions (PTF) for use with the Parameter Estimation Tool, is applied to several sites in the Walnut Gulch Experimental Watershed (WGEW) in southeastern Arizona during the Monsoon '90 experiment period. It is demonstrated that the application of PTF constraints in the estimation process for hydraulic parameters provides accuracy similar to direct hydrologic parameter estimation, with the additional benefit of simultaneously estimated soil texture. Precipitation uncertainty is then represented with systematically varying sources, from the high‐density precipitation gauge network in WGEW to lower quality sources, including spatially averaged precipitation, single gauges in and near the watershed, and results from the continental‐scale North American Regional Reanalysis data set. It is demonstrated that the quality of the input precipitation data set, and particularly the accuracy of the data set, in both detection of convective (heavy) rainfall events and reproduction of the observed rainfall rate probabilities, is a critical determinant in the use of successive remote sensing results in order to establish and refine estimates of soil texture and hydraulic properties.
Observations of the ion signatures of double merging and the formation of newly closed field lines
Authors: Chandler Michael O. , Avanov Levon A. , Craven Paul D. , Mozer F. S. , Moore T. E.
Published: May 2008

Observations from the Thermal Ion Dynamics Experiment (TIDE) on the Polar spacecraft, taken during a period of northward interplanetary magnetic field (IMF) show magnetosheath ions within the magnetosphere with velocity distributions resulting from two widely separated (∼30 RE) merging sites along the same field lines. These results are consistent with the hypothesis that double merging can produce closed field lines populated by solar wind plasma under northward IMF. While the merging sites cannot be unambiguously located, the directions of the flowing magnetosheath populations and the convection of merged field lines are consistent with locations of two merging sites northward of the spacecraft and the analyses favor one site poleward of the northern cusp and a second site at lower latitudes equatorward of the northern cusp.
Leukotriene D4increases the excitability of capsaicin‐sensitive nasal sensory nerves to electrical and chemical stimuli
Authors: Taylor‐Clark T E , Nassenstein C , Undem B J
Published: May 2008

Background and purpose:

Clinical studies have demonstrated significant reductions in allergen‐induced nasal symptoms of atopic rhinitis subjects by CysLT1antagonists, including neuronally mediated symptoms such as sneeze, itch and reflex hypersecretion. Here, we test the hypothesis that cysteinyl leukotrienes activate and/or alter the activity of nasal nociceptive (capsaicin‐sensitive) sensory neurones.

Experimental approach:

Using retrograde tracer (DiI), we labelled guinea‐pig trigeminal sensory neurones that projected fibres to the nasal mucosa. Single‐neurone reverse transcriptase (RT)‐PCR was used to evaluate CysLT receptor gene expression. The effect of cysteinyl leukotrienes on individual nasal sensory nerve activity was assessed in Ca2+assays and whole‐cell gramicidin‐perforated patch‐clamp studies.

Key results:

Nasal C‐fibre neurones express CysLT1but not CysLT2mRNA. LTD4and LTC4increased intracellular [Ca2+]freein a population of capsaicin‐sensitive trigeminal nerves, an effect blocked by the CysLT1antagonist ICI198615. In current clamp mode, LTD4had no effect on resting membrane potential. However, LTD4significantly increased electrical excitability (action potential discharge during current pulses) threefold in capsaicin‐sensitive nasal neurones, which was inhibited by CysLT1antagonists ICI198615 and montelukast. LTD4had no effect on electrical excitability in capsaicin‐insensitive neurones. Finally, LTD4significantly augmented histamine‐induced responses in capsaicin‐sensitive neurones as measured by increased action potential discharge, peak frequency and membrane depolarization.

Conclusions and implications:

LTD4, likely through CysLT1receptors, directly increases the excitability of capsaicin‐sensitive guinea‐pig nasal trigeminal neurones, demonstrating a novel mechanism for the actions of cysteinyl leukotrienes and potentially explains the effectiveness of CysLT1antagonists in treating nasal allergen‐induced neuronal symptoms.

British Journal of Pharmacology(2008)154, 1359–1368; doi:10.1038/bjp.2008.196; published online 26 May 2008