bluuebunny/crossref_metadata_2025 huggingface dataset:
A transition path from the zinc-blende to the NaCl type
Authors: Sowa Heidrun
Published: August 2006

In order to find a transition path from the zinc-blende to the NaCl type both structures are described with the aid of heterogeneous sphere packings. If all atoms in such crystal structures are replaced by like ones, atomic arrangements result that correspond to homogeneous sphere packings belonging to the diamond type or forming a cubic primitive lattice, respectively.

It is shown, that a diamond configuration may be deformed into a cubic primitive lattice within the Wyckoff position Imma 4(e) mm2 0,¼,z. The corresponding phase transition in binary compounds from the zinc-blende to the NaCl type can be described as a deformation of a heterogeneous sphere packing in the subgroup Imm2 of Imma. Since no bonds have to be broken this type of transition is displacive.

In addition, structural relations between high-pressure phases of semiconductors like silicon and germanium and related AB compounds are shown.
Phase transition in (NH4)H5(PO4)2
Authors: Troyanov Sergey I. , Snigireva E. M. , Kemnitz Erhard
Published: August 2006

X-ray single crystal study of (NH4)H5(PO4)2 revealed the existence of two modifications with similar unit cell dimensions. Low temperature (NH4)(H2PO4)·H3PO4 (α) was investigated at 130 K. The crystal parameters are: monoclinic, a = 10.197(4) Å, b = 7.711(2) Å, c = 9.617(3) Å, β = 101.69(4)°, Z = 4, space group P21/c, R1 = 0.0244. High temperature (NH4)[H(H2(PO4)2] (β) was investigated at 220 K. The crystal parameters are: monoclinic, a = 10.332(4), b = 7.702(3), c = 9.604(4) Å, β = 101.18(4)°, Z = 4, space group C2/c, R1 = 0.0239. The phase transition α ↔ β is characterized by a hysteresis in the temperature range 180-210 K. The ammonium cation and the H atom of a short hydrogen bond 2.445(2) Å which are ordered in the α-modification become disordered in the structure of the β-form.
Self-intersecting three-periodic minimal surfaces forming two-periodic (flat) labyrinths
Authors: Koch Elke
Published: August 2006

14 families of minimal surfaces with straight self-intersections have been derived which subdivide R3 into infinitely many congruent, two-periodic ‘flat labyrinths’. For eleven families, all flat labyrinths are parallel to each other. Two sets of mutual perpendicular flat lab-yrinths have been found three times. All these minimal surfaces are non-orientable. Their Euler characteristics vary between -3 and -13.
Mixed alkali systems: Dietzels theorem, X-ray structure, hygroscopicity, and 29-Si MAS NMR of NaRbSi2O5 and NaCsSi2O5
Authors: de Jong B.H.W.W.S. , Supèr H.T.J. , Frijhoff R.M. , Spek A.L. , Nachtegaal G.
Published: August 2006

NaRbSi2O5, Mr 244.63, λ(MoKα)=0.71073 Å, 150K, monoclinic, P21/c, a=4.8570(10)°, b=13.5403(10)°, c=7.7328(10) Å, β=90.908(10)°, V=508.49(13) Å3, μ(MoKα)=10.23 mm-1, Z=4, F(000)=464, Dx=3.1954(8) g/cm3, R1=0.0899 for 743 reflections with I>2.0σ(I), wR2=0.2425 for all 2534 reflections.

NaCsSi2O5, Mr 584.13, λ(MoKα)=0.71073 Å, 150K, orthorhombic, Pna21, a=17.0743(10)°, b=4.9011(10)°, c=13.3391(10) Å, V=1116.3(3) Å3, μ(MoKα)=7.08 mm-1, Z=8, F(000)=1072, Dx=3.4757(9)g/cm3, R1=0.0199 for 1103 reflections with I>2.0σ(I), wR2=0.0465 for all 2668 reflections.

The crystal structures of NaRbSi2O5 and NaCsSi2O5 have been determined. Though the nominal composition of both phases is that of a phyllosilicate, their anion topology is similar and consists of double chains of [SiO4] tetrahedra forming 4-membered T rings, i.e. rings consisting of 4 tetrahedra in chair conformation and built from Q3 units. The alkali-oxygen distances in the Na2O-Cs2O-SiO2 system tend to support the notion that in mixed alkali systems the alkali-oxygen distance of the smaller cation decreases at the expense of that of the larger one. The observed very high hygroscopicity of both crystalline phases might be rationalized by substantial underbonding of some of the oxygen atoms. 29-Si spin lattice relaxation times, T1, vary largely between 535 and 493 sec for NaRbSi2O5 and 2440 and 2329 sec for NaCs-Si2O5.
MgAl2O4 synthetic spinel: cation and vacancy distribution as a function of temperature, from in situ neutron powder diffraction
Authors: Pavese A. , Artioli G. , Hoser A.
Published: August 2006

Neutron powder diffraction data collection has been carried out at BENSC (Berlin, D), on synthetic Mg0.94Al2.04O4 spinel, in the temperature range 300-1700 K, to investigate the intracrystalline cation and vacancy order-disorder (OD) reaction, which begins to be detectable at 944 K. The Rietveld method has been used in combination with advanced minimization techniques to determine the occupancy coefficients of magnesium, aluminum, and vacancies on the tetrahedral and octohedral sites. The temperature dependence of the cell parameter, of the T-O and M-O bond lengths, and of the oxygen u-coordinate are discussed in the light of the OD-reactions. The cation site partitioning has been interpreted as a function of temperature using the thermodynamic model of O´Neill and Navrotsky, whose parameters [α=30(2) and β=1(3) kJ/mol]are compared with earlier determinations from literature.
Diffuse scattering in quaternary single crystals in the system Zr-Y-O-N
Authors: Kaiser I. , Boysen Hans , Frey Friedrich , Lerch Martin , Hohlwein D. , Schneider R.
Published: August 2006

The diffuse scattering of two single crystals in the quaternary system Zr-Y-O-N (Y0.04Zr0.96O1.64N0.223 and Y0.17Zr0.83O1.68N0.158) has been measured by neutron scattering in different layers of the [1-10] zone to study short range order originating from the vacancies. While trying to fit the diffuse scattering with models given in the literature remarkable discrepancies occurred. In contrast to the existing models which explain the diffuse scattering by correlated clusters of ordered vacancies, a new model is proposed based on longitudinal displacements of rigid (O-)Zr-O-units within the lattice where the distance between Zr and O (¼ of the cubic body diagonal) is kept fixed.
Structure and properties of tecto-gallosilicates. I. Hydrosodalites and their phase transitions
Authors: Gesing Th.M.
Published: August 2006

The crystal structures of the new gallosilicate hydrosodalites Na5[Ga0.8Si1.2O4]6 (H2O)8 was refined from X-ray powder data in the bodycentred space group I-43m: a = 884.15 pm, V = 0.6912 nm3, Z = 2, RWP = 0.063, RP = 0.048, RI = 0.014 for 6000 data points and 12 variable positional parameters. The statistical distribution of the gallium and silicon atoms on the tetrahedral framework positions was proved by 29Si MAS NMR. TG/DSC experiments and in situ X-ray heating measurements indicate a phase transition of this compound to the phase Na0.8Ga0.8Si1.2O4. The sodalite Na6[GaSiO4]6(H2O)8 was reinvestigated from X-ray powder data in the space group P-43n: a = 885.92 pm, V = 0.6953 nm3, Z = 2, RWP = 0.047, RP = 0.033, RI = 0.017 for 2000 data points and 10 variables. Here the tetrahedral atoms are completely ordered as shown in the 29Si MAS NMR spectrum. Additionally, the structure was refined from single crystal diffractometer data using a very small crystal. This refinement resulted in: a = 887.8 pm, V = 0.6998 nm3, Z = 2, wR2 = 0.046, R = 0.043 for 294 observed data and 24 variable parameters. Heating this compound to 1173 K shows a phase transition which resulted in this case in the phase NaGaSiO4-I. This phase was also refined from powder data in the hexagonal space group P63: a = 872.9 pm, c = 820.8 pm V = 0.5416 nm3, Z = 6, RWP = 0.069, RP = 0.047, RI = 0.026 for 2000 data points and 20 variables. In comparison to similar structures reported before, the hexagonal space group was chosen. Because two reflections could not be explained with this symmetry, it is possible that the compound crystallises in a pseudo-hexagonal orthorhombic space group. Additionally, IR and Raman spectra of all compounds were recorded.
Low-temperature crystallization and X-ray structure determination of hexafluoropropene at 95 K
Authors: Luger P. , Bach A. , Buschmann J. , Lentz D.
Published: August 2006

Crystals of hexafluoropropene, C3F6, melting point 115 K, were obtained by low temperature crystallization on the diffractometer in a cold N2 gas stream. The crystal structure was solved based on a dataset of 1347 reflections ((sinθ/λmax = 0.66 Å-1 ) measured at 95 K. C3F6 crystallizes in the triclinic space group P-1 (No. 2), a = 6.072(6) Å, b = 6.233(5) Å, c = 6.569(6) Å, α = 92.33(5)°, β = 108.75(7)°, γ = 94.31(5)°, V = 234.2(6) Å3, Z = 2, R1 = 0.050 for 729 reflections ( Fo
2 > 2σ(Fo
2)). The molecular structure has almost Cs symmetry with all atoms in a common plane except two fluorine atoms of the CF3 group. The fluorine atom of the CF3 group in the molecular plane is in trans position to the fluorine atom bonded to the central carbon atom. The geometrical parameters obtained from X-ray data are compared to those from an earlier gas phase electron diffraction study and, moreover, to those, obtained by theory from different high level ab initio calculations which were carried out as well for hexafluoropropene as for propene itself.
Pyridine type complexes of transition-metal halides XI.Structural, thermal and spectroscopic studies of aminopyridine complexes of cobalt(II) halides
Authors: Csöregh I. , Kenessey G. , Wadsten T. , Liptay G. , Carson B.R.
Published: August 2006

Crystalline ternary mixed aminopyridine complexes of cobalt(II) chlorides and cobalt(II) bromides have been prepared and analysed by means of thermal (TG, DTG, DTA) methods, UV/VIS spectroscopy, magnetic measurements and X-ray powder diffraction techniques. The symmetry and cell dimensions have been calculated using TREOR 90, a trial-and-error indexing program. One of the compounds, namely the [Co(3-NH2-pyridine)4Cl2] complex has been studied also by X-ray single-crystal diffraction, yielding a propeller-shaped molecule with octahedral co-ordination, exhibiting both molecular and crystallographic inversion symmetry. Crystal data: C20H24N8Cl2Co, Mw = 506.30, triclinic (P-1) unit cell with a = 7.684(1), b = 8.582(1), c = 9.966(2) Å, α = 73.17(1), β= 69.97(1), γ = 70.33(1)°, Vc = 570.0(2) Å3 and Z = 1. The structure model was refined to R = 0.027 and wR = 0.037 for 2680 reflections with I > 3σ(I).
Crystal structure of M(IO3)2 metal iodates, twinned bypseudo-merohedry, with MII: MgII, MnII, CoII, NiII and ZnII
Authors: Phanon Delphine , Bentria Bachir , Jeanneau Erwann , Benbertal Djamal , Mosset Alain , Gautier-Luneau Isabelle
Published: August 2006

The non-centrosymmetric materials Zn(IO3)2, Mn(IO3)2, Co(IO3)2, Mg(IO3)2 and β-Ni(IO3)2 have been synthesised by evaporation of nitric acid solutions of metal salts and lithium iodate. All these compounds are isostructural and their structures were characterised both by X-ray diffraction on powder and single crystals. They crystallise in the monoclinic crystal system, space-group type P21 (no. 4) with a pseudo-hexagonal lattice, as shown by the lattice parameters of Mn(IO3)2 for example: a = 11.247(1) Å, b = 5.045(1) Å, c = 11.246(1) Å, β = 120.02(1)°, V = 552.5(1) Å3, Z = 4. This monoclinic symmetry with a ∼ c and β ∼ 120° leads to a three-individual pseudo-hexagonal twin by pseudo-merohedry. The structure reveals a three-dimensional network in which each octahedrally coordinated cation is linked to ten others via iodate bridges. All these metal iodates generate second harmonics.
Gibbs Energy of Transfer of H+ Ion from Water to Urea-Water Mixtures
Authors: Dey B.P. , Lahiri Sujit Chandra
Published: August 2006

The thermodynamic dissociation constants for the isoelectronic reaction LH
Elementary Reaction of CF2(X~) with O3: Primary Products
Authors: Beiderhase T. , Hoyermann Karlheinz , Hack Walter
Published: August 2006

The reaction of CF

The following primary products were observed (CF

CF

→ CF

explains the observed primary products. The molecule with the empirical formula CF
Collision Model of `Fall-Off´ in Recombination Reactions
Authors: Nyeland C.
Published: August 2006

Assuming random, multiple collisions the `fall-off´ problem in chemical recombination reactions is reconsidered. Following this approximative model the `fall-off´ from third order reactions at low pressure to second order reactions at high pressure appears in a simple way as a consequence of the collision time considered as the lifetime of the unstable van der Waals complex formed initially in the recombination mechanism.

Comparisons are presented for results from the `fall-off´ following the Lindemann type mechanism, and of the method of Troe, Gilbert
Is there any Correlation between the Mobility and the Absorption Spectra of Solvated Electrons in Polar Solvents?
Authors: Krebs P.
Published: August 2006

Some years ago Jay-Gerin and Ferradini attempted to establish a correlation between the optical absorption spectrum and the mobility of excess electrons in various polar solvents (J. Chem. Phys.
Laser Phase Control of Electron-Nuclear Dynamics in Dissociative Ionization with Intense Femtosecond Pulses: Exact (non-Born-Oppenheimer) Numerical Simulations for H+2
Authors: Bandrauk A.D , Chelkowski S. , Zamojski M.
Published: August 2006

Exact numerical solutions of the time-dependent Schroedinger equation, TDSE of a 1-D H
The Heterogeneous Kinetics of the Reactions ClONO2 + HX/ice (X = Br, I), BrONO2 + HI/ice and the Reactivity of the Interhalogens BrCl, ICl and IBr with HX/ice (X = Cl, Br, I) in the Temperature Range 180 to 205 K
Authors: Allanic A. , Oppliger R. , Bergh H. van den , Rossi M.J.
Published: August 2006

The kinetics and mechanism of the title heterogeneous halogen exchange reactions of potential atmospheric importance have been studied under molecular flow conditions in a FEP Teflon-coated Knudsen flow reactor on HX (X = Cl, Br, I) - doped ice condensed from the vapor phase under conditions of several formal monolayers of HX coverage at approximately 200 K. In addition, the halogen exchange reactions involving the expected primary reaction products BrCl, ICl and IBr of the above mixed anhydrides with HX-doped ice have been studied at 200 K as well. The uptake coefficient γ for the heterogeneous reaction ClONO
Nuclear Magnetic Relaxation Measurements on Liquid Acetonitrile and Acetonitrile Water Mixtures
Authors: Hardy E.H. , Zygar A. , Zeidler M.D.
Published: August 2006

Precise temperature dependent H, D,

By a new method, the acetonitrile deuterium quadrupole coupling constant was determined to 162(6) kHz.

An isotope effect of about 5% on the acetonitrile correlation time of the reorientation of the symmetry axis is observed. It decreases if the water content is increased. For the effective correlation time of the C-H/D vector the isotope effect is about 25%. This effect was separated into a contribution of 3% for only one molecule which is deuterated and 21% for the deuteration of the remaining molecules.

The anisotropy of the reorientation of acetonitrile was calculated in the limit of rotational diffusion. In neat deuterated ammonia the reorientation about the symmetry axis is about ten times faster than the reorientation of the symmetry axis itself. Due to different activation energies the anisotropy increases with decreasing temperature. The isotope effect is also anisotropic and the rotational anisotropy in protonated acetonitrile is about fourteen. The anisotropy is higher in the binary mixtures. At the critical composition it is fourteen for the deuterated and twenty for the protonated sample.

In the mixture of critical composition simultaneous relaxation measurements on both phases were possible. This allows a determination of the coexistence curve. No anomaly of the rates was observed on approaching the coexistence curve.
Studies on Hydrogen Bond Formation of Papaverine and Pentazocine
Authors: Gangopadhyay J. , Lahiri Sujit Chandra
Published: August 2006

Hydrogen bond formation is important in drug-receptor interactions.

Therefore the hydrogen bond formation of the drugs papaverine and pentazocine with alcohols and phenols were studied. The results suggest that hydrogen bonding is more prominent in papaverine than hydrophobic interactions whereas the reverse is the case for pentazocine where hydrophobic interactions overweigh its hydrogen bonding capability.
Standard Volumes of Transfer for Some α-Amino Acids from Water to Aqueous Sodium Acetate Solutions at 298.15 K
Authors: Wang Jianji , Yan Z. , Zhuo Kelei , Liu D.
Published: August 2006

Apparent molar volumes, V
The OH-yield in the reaction of O(1D) + CH4 under high pressure conditions up to 560 bar helium
Authors: Ausfelder F. , Hippler H. , Striebel F.
Published: August 2006

The pressure dependence of the OH yield in the reaction O(
Pressure and Temperature Dependence of the Decomposition Rate of Aliphatic tert-butyl Peroxyesters
Authors: Buback Michael , Sandmann J.
Published: August 2006

The thermal decomposition in solution of
Comparison of Trapping Sites of Anthracene in Hexagonal and Cubic Argon Matrices: a Molecular Dynamics Study
Authors: Horinek D. , Dick B.
Published: August 2006

Geometries and energies for possible trapping sites of anthracene in hexagonal closed packed (hcp) argon matrices have been calculated and compared to corresponding trapping sites calculated for the face centered cubic fcc argon host. The random search method (RSM) has been applied which combines statistical and molecular dynamics (MD) components in the generation of initial geometries and their relaxation. A total of 1322 runs yielded 12 unique site structures. In none of them the anthracene is located in the {111}-plane of the host crystal, in contrast to the situation found for the fcc host structure.
Temperature Dependence of Collisional Deactivation of Highly Vibrationally Excited Biphenylene
Authors: Fay N. , Luther K.
Published: August 2006

Collisional energy transfer between highly vibrationally excited biphenylene and a variety of mono- and polyatomic bath gases has been measured at temperatures between 333 and 523 K. Biphenylene molecules were initially prepared with an additional vibrational energy of 28490 cm
Nonlinear Approach to Nonequilibrium Solvation
Authors: Raineri F.O. , Friedmann T. L.
Published: August 2006

We investigate an alternative approach to the study of the solvent response to the sudden change in the charge distribution of a solute molecule. The theory avoids the assumption that the response induced in the solvent is linear with respect to the solute perturbation. Our method focuses on the nonequilibrium characteristic function g
Collision-Induced Dissociation Dynamics of the [OCS · C2H2]+ Complex. A Combined Experimental and Theoretical Study
Authors: Muntean F. , Armentrout P.B.
Published: August 2006

Collision-induced dissociation (CID) of the [OCS · C
On the Dissipative Properties of Coherent Radiation
Authors: Makri N. , Shao J.
Published: August 2006

The effects of coherent radiation on a general molecular system are studied by evaluating the influence functional of the field. It is shown that the quantized radiation field is equivalent to a classical driving term plus a dissipative term equivalent to that of the vacuum state. It is thus concluded that the dissipative character of quantized radiation cannot be controlled by adjusting the intensity of the beam.
Studies on Thermodynamic Dissociation Constants of 2,2’-Bipyridine, or 1,10-Phenanthroline in Acetone + Water Mixtures and Gibbs Energy of Transfer of the Hydrogen Ion from Water to Acetone + Water Mixtures
Authors: Bandyopadhyay G. , Lahiri Sujit Chandra
Published: August 2006

The thermodyamic dissociation constants for isoelectric reaction of the type LH+ ⇔ L + H+ (where L = 2,2’-bipyridine or 1,10-phenanthroline) have been determined pH-metrically at 298 K in acetone + water mixtures (0-90% of acetone). The pK-values were found to pass through a minimum at about 64-74 Wt% of acetone and then increase. The data are utilized to calculate the Gibbs energies of transfer of the H+ ion from water to acetone + water mixtures from which inferences have been made regarding structural variations and solvent basicity of aquo-organic mixtures.

Attempts have been made to understand the basicity and structural properties of acetone + water mixtures from a comparative study of ΔG0
t(H+) profiles, excess relative permittivity εE
r(X) and excess Gibbs energy profiles. Acetone has been found to structure forming over the whole composition range and structure formation is maximum in the region 60-70 Wt% of acetone.
Position and Momentum Space Variables
Authors: Smith V. H. Jr.
Published: August 2006

The use of position space and momentum space variables, coordinates and operators, is discussed with emphasis on the controversy in the case of spherical polar coordinates.
Orbitals observed by Electron Momentum Spectroscopy
Authors: McCarthy I. E.
Published: August 2006

Numerical representations of Dyson orbitals can be extracted from the experimental data of electron momentum spectroscopy (EMS). These orbitals are solutions of the quasiparticle equation for the target electronic system. They closely obey the weak-coupling approximation. This defines a normalized Dyson orbital in terms of the sum of EMS cross sections for an orbital manifold of ion states whose momentum profiles have the same shape. Normalized Dyson orbitals are closely related to the orbitals of density functional theory. They are realistic in the sense that they give an independent-particle approximation to the target structure that reproduces experimental data, including molecular data obtained from experiments independent of EMS.
X-Ray Scattering in the Resonance Region: Atomic Hydrogen
Authors: Bonham R. A.
Published: August 2006

An approximate theory for the scattering of X-rays by free atoms in the resonance region for both elastic and inelastic scattering is developed based on the exact results through first order in perturbation theory of non relativistic X-ray scattering obtained by Gavrila and Costescu [Phys. Rev. A
Design and Performance of a Miniature Cryostat for Emission Measurements in Liquid Helium
Authors: Jasny J. , Slenczka A. , Dick B.
Published: August 2006

A miniature cryostat for optical emission measurements is described which uses a standard storage dewar as the liquid helium bath. Excitation and emission light is guided to and from the sample by optical fibres and spherical mirrors.
Tautomerization and Dissociation of Dimethyl Phosphonate Ions(CH3O)2P(H)=O•+:Theory and Experiment in Concert
Authors: Heydorn L.N. , Ling Y. , Oliveira G. de , Martin J.M.L: , Lifshitz C. , Terlouw J.K.
Published: August 2006

The unimolecular gas phase chemistry of the title ion,(CH

The identity of the ions was probed by tandem mass spectrometry methods. These include MI (metastable ion) or CID (collision induced dissociation) spectra, consecutive MI/CID and CID/CID spectra, NRMS (neutralization-reionization mass spectra), NR/CID and CIDI (collision induced dissociative ionization) spectra, time-resolved CID spectra and deuterium labelling. The energetics of the CH

Theory and experiment yield a consistent potential energy profile that describes the isomerization and low energy dissociation chemistry of ions
Molecular Properties of Computationally Difficult Diatomic Systems: O2, F2-, Cl2-, SiF, SiCl, ClO and MgO
Authors: Janoschek R. , Kalcher J.
Published: August 2006

For seven difficult diatomic molecules, O
Nonequilibrium Excitation of C2 Radicals during the Thermal Decomposition of C3 O2 behind Shock Waves
Authors: Deppe J. , Emelianov A. , Eremin A. , Friedrichs G. , Shumova V. , Wagner H.Gg. , Zaslonko I.
Published: August 2006

C
Determination of the Branching Ratios of CaBr(A2Π1/2,3/2, B2Σ+) Resulting from the Reaction of Ca[4s4p (3PJ)] with CH3Br by Time-Resolved Atomic Emission and Molecular Chemiluminescence Following Pulsed Dye-Laser Excitation of Atomic Calcium
Authors: Husain D. , Geng J. , Castano F. , Sanchez Rayo M.N.
Published: August 2006

Molecular electronic branching ratios to yield CaBr(A
Calorimetric Behaviour of Primary Bromobutanes with Isomeric Butanols
Authors: Artigas H. , Lafuente C. , Cea P. , López M.C. , Royo F.M.
Published: August 2006

Excess enthalpies for mixtures of 1-bromobutane or 1-bromo-2-methylpropane with isomeric butanols were determined at the temperatures of 298.15 and 313.15 K. All the systems show positive excess enthalpies. Predictions with the modified UNIFAC method were also obtained.
Speeds of Sound and Isentropic Compressibilities of Ethylene Glycol Dimethyl Ether-n-Alcohol mixtures at 298.15 K
Authors: Pal A. , Dass G.
Published: August 2006

The speeds of sound
Prospects for Molecular Spectroscopy at High Spatial Resolution
Authors: Hamann F.
Published: August 2006

This work discusses the prospects and feasibility of optical spectroscopy and microscopy of single molecules at nanometer resolution via apertureless, antenna-based near-field scanning optical microscopy. First, different near-field optical methods are compared, which detect the weak scattering or fluorescence from a probe–single molecule interaction at high spatial resolution. Specifically, ultimate sensitivities of coherent (bright-field) and non-coherent (dark-field) apertureless near-field microscopes for resonant (e.g., scattering, absorption) and non-resonant (e.g.,
Elektrochemische Rauschanalyse (ENA) zur Charakterisierung von Keimbildungs- und Wachstumsprozessen bei der elektrolytischen Metallabscheidung
Authors: Dörfel Matthias , Reents B. , Rahner D. , Plieth W.
Published: August 2006

In dieser Arbeit werden Methoden zur Erfassung und Analyse des natürlichen elektrochemischen Rauschens während der katodischen Abscheidung von Silber auf Platin aus einem cyanidischen Elektrolyten beschrieben. Es wird gezeigt, daß es bei gezieltem Einsatz von Filtertechnik möglich ist, u.a. die mittleren Nucleationsraten von Keimbildungs- und Wachstumsprozessen anhand der dominierenden Frequenzen der Leistungsdichtespektren des Rauschens
Measurements of the Rates of Reactions of Ground State Atomic Calcium, Ca[4s2(1S0)], with Alkyl Bromides at Elevated Temperature by Time-Resolved Atomic Resonance Absorption Spectroscopy [Ca(41P1 - 41S0); λ = 422.7 nm]
Authors: Geng J. , Husain D.
Published: August 2006

We present a kinetic study of reactions of ground state atomic calcium, Ca[4
Kinetics and Mechanism of the Thermal Gas-Phase Reaction between NO2 and Trifluorochloroethene
Authors: Romano Rosana M. , Védova C. O. della , Czarnowski J.
Published: August 2006

The reaction of NO

1. NO

2. O

3. O
Effects of Pressure on Two Types of Complexations of 4-Dimethylaminoazobenzene with β-Cyclodextrin
Authors: Sueshi Y. , Yoshioka C. , Hishikawa H. , Yamamoto S.
Published: August 2006

Two types of complexations between β-cyclodextrin (CD) and 4-dimethylaminoazobenzene were found in methanol-water and in dimethyl sulfoxide-water mixtures. One was an inclusion complex and the other was a lid type. The effects of pressure on the two complexations with β-CD were examined.
Protonation and Salting-in Behaviour of Weak Organic Bases in HClO4
Authors: Tiwari N. , Pande R.
Published: August 2006

Various protonation parameters (p
Randomness, Structural Uniqueness, Modularity and Neutral Evolution in Sequence Space of Model Proteins
Authors: Bornberg-Bauer Erich
Published: August 2006

The genotype-phenotype map for short chains of a protein-like hetero-polymer model has been characterised [9, 12]. Hydrophobic-Polar (HP) sequences on a square lattice, their structures and partition functions have been exhaustively enumerated and analysed. Homologous sequences folding uniquely into the same structure are interconnected by point mutations. These
Absence of Dual Fluorescence in Cyano Isomers and Di-Cyano Derivatives Related to N,N-Dimethyl-4-Aminobenzonitril: A DFT/MRCI Study
Authors: Parusel A.B.J. , Schamschule R. , Köhler G.
Published: August 2006

A combination of density functional theory and multi-reference configuration interaction method (DFT/MRCI) is used to investigate the excited state intramolecular charge transfer (ICT) reaction for the
Periodic Forcing of NO Reduction on a Pt(100) Surface
Authors: Schütz Eckart , Imbihl Ronald
Published: August 2006

The influence of a cycled gas feed on reactions of the automotive catalytic converter has been investigated under low pressure conditions (
Complex Pacemakers and Wave Sinks in Heterogeneous Oscillatory Chemical Systems
Authors: Stich Michael , Mikhailov Alexander S.
Published: August 2006

We investigate pattern formation in oscillatory reaction-diffusion systems where wave sources and sinks are created by a local shift of the oscillation frequency. General properties of resulting wave patterns in media with positive and negative dispersion are discussed. It is shown that phase slips in the wave patterns develop for strong frequency shifts, indicating the onset of desynchronization in the medium.
Chemo-Mechanical Coupling and Pattern Formation in a Complex Reaction System
Authors: Steinbock O. , Kasper E. , Müller Stefan C.
Published: August 2006

We report experimental results on the formation of macroscopic concentration patterns in the polyacrylamide-methylene blue-oxygen-sulfide (PA-MBO) reaction. The patterns have the geometry of stripes or hexagons. The latter transform to more complicated structures within the gelled medium. For the case of hexagons, the pattern wavelength (here 1-5 mm) shows a nearly proportional dependence on the height of the reaction layer. The system generates colloidal particles (average diameter 30 µm) that we use to monitor the physical changes within the medium. Our results reveal three distinct phases of particle movement. The first one is caused by hydrodynamic flows within the pre-gel solution, whereas the third, and possibly the second, phase arises from localized volume changes within the gel matrix.
Relative Electrical Resistance of Pd Saturated by Gaseous Deuterium in a Wide Pressure Range at 298 K
Authors: Baranowski B. , Filipek S.M.
Published: August 2006

The relative electrical resistance of Pd-D system as a function of deuterium content at 278 K is presented in the total concentration range available so far. The data include results up to 0.7
Oxidation of (+)-(R)-Pantothenic Acid by Aqueous Alkaline Potassium Permanganate: A Kinetic and Mechanistic Approach
Authors: Desai S.M. , Halligudi N.N. , Mavalangi S.K. , Nandibewoor S.T.
Published: August 2006

The kinetics of oxidation of (+)-(R)-pantothenic acid (PA) by permanganate in aqueous alkaline medium at constant ionic strength 0.20 mol dm
Ultrasonic Speeds, Molar Excess Volumes and Adiabatic Compressibilities of the 1-Butanol + Glycerol System at 298.15 K
Authors: Zorebski E. , Nurek J.
Published: August 2006

Ultrasonic speeds in and densities of mixtures of 1-butanol with glycerol have been measured at 298.15 K. The excess values of the molar volume and molar adiabatic compressibility (as well as adiabatic compressibility coefficient) were estimated. Also deviations of the ultrasonic speeds from the values calculated for ideal mixtures were determined. All the excess quantities are expressed by the Redlich-Kister polynomials and disscused in terms of molecular interactions.
Transference Numbers, Conductance and Viscosity Studies of Copper Sulfate in Ethylene Glycol–Water Mixtures at 20 °C
Authors: Tsierkezos Nikos G. , Molinou Ioanna E.
Published: August 2006

Cell voltage (emf), conductivities and viscosities of copper(II) sulfate solutions in ethylene glycol–water mixtures have been measured at 20 °C. The transference numbers of CuSO

Die EMK, Leitfähigkeiten und Viskositäten von CuSO
Effect of β-Cyclodextrin on the Micellar Behavior of Cetylpydinium Chloride in Aqueous Solution
Authors: Yang J.-Z. , Wang Jianji , Yue Y. , Zhuo Kelei
Published: August 2006

Molar volume and conductivity measurements have been carried out at 298.15 K for cetylpydinium chloride (CPC) + H
Postnatal changes in testicular gonadotropin receptors, serum gonadotropin, and testosterone concentrations and functional development of the testes in bulls
Authors: Bagu E T , Cook S , Gratton C L , Rawlings N C
Published: August 2006

The primary objectives of this study were to follow the temporal patterns of testicular LH and FSH receptor (LH-R and FSH-R) concentrations and affinity (Ka) during sexual maturation in bulls and to see if such patterns could help explain the control of rapid testicular growth that occurs after 25 weeks of age, when serum gonadotropin concentrations are low. Separate groups of Hereford × Charolais calves (n = 6) were castrated every 4 weeks from 5 to 33 weeks of age and at 56 weeks of age. A week prior to castrations, from 5 to 33 weeks of age, blood was collected every 15 min for 10 h. The transition from indifferent supporting cells to Sertoli cells in seminiferous tubules was rapid between 13 and 25 weeks and rapid testis growth occurred after 25 weeks of age. Serum LH and FSH concentrations were transiently elevated at 12 weeks of age (P < 0.05). LH-R concentrations decreased from 13 to 25 weeks of age and increased to 56 weeks of age (P < 0.05). LH-RKa decreased from 9 to 17 weeks of age, increased to 29 weeks of age and declined to 33 weeks of age (P < 0.05). FSH-R concentrations declined from 17 to 25 weeks of age then increased to 56 weeks of age (P < 0.05). FSH-RKa increased from 17 to 25 weeks of age (P < 0.05). High concentrations of gonadotropins and their receptors may be critical to initiate testis growth postnatally and support it after 25 weeks of age in the face of low serum gonadotropin concentrations.
Cloning of porcine signal transducer and activator of transcription 3 cDNA and its expression in reproductive tissues
Authors: Wen Lihua , Craig Jesse , Dyce Paul W , Li Julang
Published: August 2006

The signal transducer and activator of transcription 3 (Stat3) protein is a member of the Stat family that has a variety of biological functions including cell growth, anti-apoptosis, and cell motility, depending on the cell type and stimulus. Recent studies have suggested that Stat3 plays an important role in embryo development. Although the Stat3 gene has been cloned in humans, mice, cow, and rats, its sequence in pigs is unknown. In the present study, the 2476 bp Stat3 cDNA was cloned using real time reverse transcriptase (RT)-PCR. Comparison of sequences across species revealed that the porcine Stat3 cDNA is 93 and 90% homologous to human and mouse respectively. To study the expression pattern of Stat3, RNA and protein were isolated from heart, lung, kidney, ovary, oviduct, and uterus tissues. RT-PCR and western blot indicated that Stat3 is expressed in all the tissues tested, and the level of expression is relatively high in tissues from the reproductive system. In addition, immunohistochemistry studies suggested that the Stat3 protein was present in the oocyte, granulosa, theca, and interstitial cells of the ovary, the mucosal folds in the oviduct, and both the epithelium and stromal layers in the endometrium. To study whether Stat3 is functional in responding to growth factor stimulation in the ovary, granulosa cells were isolated from large follicles (>3 mm) and cultured in the presence of epidermal growth factor (EGF; 10 ng/ml) for 5, 10, 15, 30, and 60 min, following which western blots were performed using an antibody against the phosphorylated Stat3. Phosphorylated Stat3 was upregulated following 5 min of EGF challenge and was sustained during the 15-min stimulation, and decreased back to the control level following 60-min stimulation. The translocation of phosphorylated Stat3 from cytoplasm to nucleus following stimulation of EGF was also detected via immunocytochemistry. Our data suggests that Stat3 may play a role in porcine ovarian function.
Role of Src homology 2 domain-mediated PTK signaling in mouse zygotic development
Authors: Meng Li , Luo JinPing , Li Chunhua , Kinsey William H
Published: August 2006

Fyn and other Src-family kinases play an essential role at several steps during egg activation following fertilization of externally fertilizing species, such as marine invertebrates, fish, and frogs. Recent studies demonstrate that the requirement for Src-family kinases in activation of the mammalian egg is different from lower species, and the objective of this study was to test the role of the Fyn kinase in the mouse egg activated by intracytoplasmic sperm injection (ICSI). An Src homology 2 (SH2) domain containing fusion protein was used to suppress Fyn function in the mouse zygote following ICSI. Eggs injected with the Fyn SH2 domain at an intracellular concentration of 4–8 μM exhibited reduced developmental potential with 100% of the zygotes being arrested following the first or the second cleavage. At higher concentrations, the protein blocked pronuclear congression and the zygotes remained at the pronuclear stage. The SH2 domain had no effect on sperm-induced calcium oscillations in distinct contrast to its effect on the eggs of lower species. The results indicate that the SH2 domain of Fyn kinase plays an important role in pronuclear congression as well as early cleavage events and that this effect appears not to involve disruption of calcium oscillations.
In vitro fertilisation with frozen–thawed bovine sperm sexed by flow cytometry and validated for accuracy by real-time PCR
Authors: Puglisi Roberto , Vanni Roberta , Galli Andrea , Balduzzi Donatella , Parati Katia , Bongioni Graziella , Crotti Gabriella , Duchi Roberto , Galli Cesare , Lazzari Giovanna , Aleandri Riccardo
Published: August 2006

The methodologies used for cytometric sorting of fresh spermatozoa never allowed a clear resolution of sexual chromosomes of frozen–thawed semen. To devise a novel method for the production of bovine predefined sexed embryos using frozen–thawed semen, sorting efficiency of different protocols was studied using a new quantitative real-time PCR method to verify the purity of sexed semen. To this aim, after Percoll separation, frozen–thawed samples were stained at different temperatures and concentrations of Hoechst 33342 using a short-incubation time. The concentration of Hoechst 33342 of 500 μg/ml at a temperature of 37 °C provided good and stable fluorescence signals. Preventing the sperm clustering by adding 0.6% BSA in the 90% Percoll fraction led to X-bearing sperms purity of 91±2%. Thereafter, sorted sperms were used for in vitro fertilisation (IVF). Despite the lower cleavage rates reported in the sorted groups when compared with the control groups (40 vs 48%, P<0.01), blastocyst formation in the sorted and control groups was not different (27 vs 24% of the cleaved respectively). The PCR analysis of 30 blastocysts confirmed 26 embryos to be correctly sexed (87%). Transfer of two embryos per recipient into six synchronised heifers resulted in four pregnancies. Two abortions occurred at day 60, while two pregnancies went to term delivering two female calves. In conclusion, high purity and repeatabilityof sorting was obtained with frozen–thawed bull semen that was subsequently used for IVF giving rise toviable embryos and offspring. In addition, real-time PCR revealed to be an optimal support for these studies, providing a rapid and reliable estimation of flowcytometric efficiency.
Simultaneous Estimation of Mixing Rates and Genetic Drift Under Successive Sampling of Genetic Markers With Application to the Mud Crab (Scylla paramamosain) in Japan
Authors: Kitakado Toshihide , Kitada Shuichi , Obata Yasuhiro , Kishino Hirohisa
Published: August 2006

In stock enhancement programs, it is important to assess mixing rates of released individuals in stocks. For this purpose, genetic stock identification has been applied. The allele frequencies in a composite population are expressed as a mixture of the allele frequencies in the natural and released populations. The estimation of mixing rates is possible, under successive sampling from the composite population, on the basis of temporal changes in allele frequencies. The allele frequencies in the natural population may be estimated from those of the composite population in the preceding year. However, it should be noted that these frequencies can vary between generations due to genetic drift. In this article, we develop a new method for simultaneous estimation of mixing rates and genetic drift in a stock enhancement program. Numerical simulation shows that our procedure estimates the mixing rate with little bias. Although the genetic drift is underestimated when the amount of information is small, reduction of the bias is possible by analyzing multiple unlinked loci. The method was applied to real data on mud crab stocking, and the result showed a yearly variation in the mixing rate.
Clinical and Genotype Studies of Cardiac Tumors in 154 Patients With Tuberous Sclerosis Complex
Authors: Jóźwiak Sergiusz , Kotulska Katarzyna , Kasprzyk-Obara Jolanta , Domańska-Pakieła Dorota , Tomyn-Drabik Małgorzata , Roberts Penelope , Kwiatkowski David
Published: August 2006

OBJECTIVE. Tuberous sclerosis complex is an autosomal dominant disorder in which hamartomas occur in several organs. Cardiac rhabdomyomas, the most common heart tumors of childhood, are well known to be associated with tuberous sclerosis complex. Our aim for this study was to characterize the incidence, progression, and clinical consequences of tuberous sclerosis complex–associated rhabdomyomas in a large cohort of patients with TSC1 and TSC2 genotypes.

PATIENTS AND METHODS. Patients (154) with tuberous sclerosis complex were evaluated, including clinical assessment, electrocardiography, and echocardiography. Mutations in TSC1 or TSC2 genes were identified in 127 patients.

RESULTS. Cardiac rhabdomyomas were found in 74 (48%) patients. Tumors were most frequent in children younger than 2 years (65%). Tumor regression or disappearance was observed in 37 (68%) of 55 children. However, in 6 (3.9%) of them (aged 10-15 years), cardiac rhabdomyomas were noted to either grow (3 cases) or appear de novo (3 cases), such that the frequency of cardiac rhabdomyomas in adolescents was 6 (54%) of 11. Most (61%) tumors were clinically silent. Clinical manifestations included heart failure (5.4%), arrhythmias (23%), and murmurs (14.9%). One child died as a result of cardiac insufficiency. Cardiac rhabdomyomas were more frequent in theTSC2 (54%) than TSC1 (20%) groups.

CONCLUSIONS. Cardiac rhabdomyomas are seen in the majority of young children with tuberous sclerosis complex. Most produce no clinical consequences and will spontaneously regress. However, during puberty, cardiac rhabdomyomas may enlarge or appear de novo; thus, attention should be paid to potential clinical signs and monitoring by echocardiography should be performed. Cardiac rhabdomyomas were observed more often in the TSC2 group.
Dr. Szasz’s Gauntlet: A Critical Review of the Work of American Psychiatry’s Most Vocal Gadfly
Authors: Wynne Louis
Published: August 2006

This article is a digest and critical analysis of Thomas Szasz’s oeuvre based on his better known works. His position is represented by four statements, three of which are discussed in this article; the second was discussed by this author in a review of Szasz’s The Meaning of Mind published in Vol.7(2) of this journal. The four statements are: (1) All disease is underlain by tissue pathology. Without that pathology we do not face disease but only the actions of people that disturb us; (2) The mind is a fiction; (3) Mental illness is therefore a myth, and psychiatric diagnoses are bogus contrivances; and (4) Individuals are moral agents responsible for their behavior, and psychiatry is a fraud and a fake medical specialty.
Tricks of the Trade
Authors: Scott Timothy
Published: August 2006

Before receiving Food and Drug Administration approval, drug manufacturers must conduct clinical trials of their new drugs. Although all drug studies can be manipulated, antidepressant and antipsychotic drugs are particularly vulnerable to bias. The bias is not limited to the makers of these drugs. Most psychiatrists and their professional organizations strongly favor the use of neuropsychopharmacologic agents even when justifying data are lacking. This article relates an example of this bias involving antidepressants and suicide risk and then discusses 10 common research design strategies that are used to obtain the desired conclusion rather than find truth.
Fate and Speciation of Gasoline‐Derived Lead in Organic Horizons of the Northeastern USA
Authors: Kaste James M. , Bostick Benjamin C. , Friedland Andrew J. , Schroth Andrew W. , Siccama Thomas G.
Published: August 2006

Although legislation in the late 1970s significantly reduced atmospheric lead (Pb) inputs to ecosystems in North America, organic (O) horizons in forests of the northeastern USA still contain up to 30 kg of gasoline‐derived Pb ha−1 The residence time, geochemical behavior, and fate of this contaminant Pb in soils is poorly understood. Here we use forest floor time series data and synchrotron‐based X‐ray techniques to examine the mobility and speciation of Pb in O horizons collected from remote sites across the northeastern USA. At high elevation (>800 m) sites in Vermont and New York, samples collected from similar locations in 1980, 1990, and early 2000 had indistinguishable Pb contents, ranging (±1σ) from 11 to 29 kg Pb ha−1 However, at lower elevation and lower latitude sites with mixed vegetation, significant decreases in Pb amount were observed during the two‐decade study period. Lower elevation sites ranged from 10 to 20 kg Pb ha−1 in 1980, and from 2 to 10 kg Pb ha−1 20 yr later. Lead‐enriched soil grains were determined to be amorphous with microfocused X‐ray diffraction, and Pb concentrations correlated well with Fe on maps generated via microfocused X‐ray fluorescence. Bulk Pb LIII–edge X‐ray absorption spectroscopy of coniferous O horizon samples indicate that Pb is binding to iron‐rich soil particles by inner‐sphere complexes, most likely to amorphous Fe oxides. Based on our paired regional and microscopic observations, we conclude that Pb is strongly retained in well‐drained O horizons, and mobility is governed by decomposition and colloidal transport.
Nanoscale Biogeocomplexity of the Organomineral Assemblage in Soil
Authors: Kinyangi James , Solomon Dawit , Liang Biqing , Lerotic Mirna , Wirick Sue , Lehmann Johannes
Published: August 2006

Methodological constraints limit the extent to which existing soil aggregation models explain carbon (C) stabilization in soil. We hypothesize that the physical infrastructure of microaggregates plays a major role in determining the chemistry of the occluded C and intimate associations between particulate C, chemically stabilized C and the soil mineral matrix. We employed synchrotron‐based scanning transmission X‐ray microscopy (STXM) coupled with near‐edge X‐ray absorption fine structure (C 1s‐NEXAFS) spectroscopy to investigate the nanoscale physical assemblage and C chemistry of 150‐μm microaggregates from a Kenyan Oxisol. Ultra‐thin sections were obtained after embedding microaggregates in a sulfur block and sectioning on a cryo‐microtome at −55°C. Principal component and cluster analyses revealed four spatially distinct features: pore surfaces, mineral matter, organic matter, and their mixtures. The occurrence of these features did not vary between exterior and interior locations; however, the degree of oxidation decreased while the complexity and occurrence of aliphatic C forms increased from exterior to interior regions of the microaggregate. At both locations, compositional mapping rendered a nanoscale distribution of oxidized C clogging pores and coating pore cavities on mineral surface. Hydrophobic organic matter of aromatic and aliphatic nature, representing particulate C forms appeared physically occluded in 2‐ to 5‐μm pore spaces. Our findings demonstrate that organic matter in microaggregates may be found as either oxidized C associated with mineral surfaces or aromatic and aliphatic C in particulate form. Using STXM and C 1s‐NEXAFS we are for the first time able to resolve the nanoscale biogeocomplexity of unaltered soil microaggregates.
Heavy Metal Contamination of Soil
Authors: Basta N.T.
Published: August 2006

Iqbal Ahmad, S. Hayat, and J. Pichtel (ed.). Science Publishers, Inc., Box 699, Enfield, NH 03748. 2005. 262 p. $85.00. Hardcover. ISBN 1–57808–385–0.
Hydrology
Authors: Si Bing
Published: August 2006

Wilfried Brutsaert. Cambridge University Press, Cambridge University Press, 40 West 20th Street, New York, NY 10011‐4221. 2005. Hardback, 618pp. $75.00. ISBN‐10: 0‐521‐824796.