bluuebunny/crossref_metadata_2025 huggingface dataset:
Evaluation of the relationship between causative organisms and clinical characteristics of infective endocarditis in dogs: 71 cases (1992–2005)
Authors: Sykes Jane E. , Kittleson Mark D. , Pesavento Patricia A. , Byrne Barbara A. , MacDonald Kristin A. , Chomel Bruno B.
Published: June 2006

Objective—To evaluate microbiologic findings in dogs with infective endocarditis (IE) and determine whether there were differences in clinical features of disease caused by different groups of infective agents.

Design—Retrospective case series.

Animals—71 dogs with suspected or definite IE.

Procedures—Medical records were reviewed for results of bacterial culture and susceptibility testing, serologic assays for vector-borne disease, and PCR testing on vegetative growths. Cases were grouped by causative organism and relationships among infectious agent group, and various hematologic, biochemical, and clinical variables were determined. Survival analyses were used to determine associations between infecting organisms and outcome.

Results—Causative bacteria were identified in 41 of 71 (58%) dogs. Gram-positive cocci were the causative agents in most (21/41; 51%) infections, with Streptococcus canis associated with 24% of infections. Gramnegative organisms were detected in 9 of the 41 (22%) dogs. Infection with Bartonella spp was detected in 6 of 31 (19%) dogs with negative results for microbial growth on blood culture. Aortic valve involvement and congestive heart failure were more frequent in dogs with endocarditis from Bartonella spp infection, and those dogs were more likely to be afebrile. Infection with Bartonella spp was negatively correlated with survival. Mitral valve involvement and polyarthritis were more frequent in dogs with streptococcal endocarditis.

Conclusions and Clinical Relevance—Streptococci were the most common cause of IE and were more likely to infect the mitral valve and be associated with polyarthritis. Dogs with IE secondary to Bartonella spp infection were often afebrile, more likely to develop congestive heart failure, rarely had mitral valve involvement, and had shorter survival times.
Use of a multivariable model to estimate the probability of discharge in hospitalized foals that are 7 days of age or less
Authors: Rohrbach Barton W. , Buchanan Benjamin R. , Drake Jennifer M. , Andrews Frank M. , Bain Fairfield T. , Byars Douglas T. , Bernard William V. , Furr Martin O. , Paradis Mary Rose , Lawler Jacquelin , Giguère Steeve , Dunkel Bettina
Published: June 2006

Objective—To create a mathematical model to assist in early prediction of the probability of discharge in hospitalized foals ≤ 7 days old.

Study Design—Prospective study.

Animals—1,073 foals.

Procedures—Medical records from 910 hospitalized foals ≤ 7 days old for which outcome was recorded as died or discharged alive were reviewed. Thirty-four variables including historical information, physical examination findings, and laboratory results were examined for association with survival. Variables associated with being discharged alive were entered into a multivariable logistic regression model. Accuracy of the model was validated prospectively on data from 163 foals.

Results—Factors in the final model included age group, ability to stand, presence of a suckle reflex, WBC count, serum creatinine concentration, and anion gap. Sensitivity and specificity of the model to predict live discharge were 92% and 74%, respectively, in the retrospective population and 90% and 46%, respectively, in the prospective population. Accuracy of an equine clinician's initial prediction of the foal being discharged alive was 83%, and accuracy of the model's prediction was 81%. Combining the clinician's prediction of probability of live discharge with that of the model significantly increased (median increase, 12%) the accuracy of the prediction for foals that were discharged and nonsignificantly decreased (median decrease, 9%) the accuracy of the predication for nonsurvivors.

Conclusions and Clinical Relevance—Combining the clinician's initial predication of the probability of a foal being discharged alive with that of the model appeared to provide a more precise early estimate of the probability of live discharge for hospitalized foals.
Synthesis, characterization and optical properties of silver and gold nanowires embedded in mesoporous MCM-41
Authors: Adhyapak Parag , Karandikar Prashant , Dadge Jagdish , Aiyer Rohini , Chandwadkar Asha
Published: June 2006

Uniform nanowires of silver and gold inside the channels of MCM-41 were prepared by controlled reduction of their respective metal salts with sodium borohydride (NaBH4). Presence of nanowires of silver and gold in MCM-41 were confirmed by high angle X-ray diffraction (XRD) data (peaks between 2ϑ = 30 − 60°) and transmission electron microscopy (TEM) confirmed the diameter of the nanowires. Diameter of nanowires is found to be ∼ 2.8 nm which is coincident with channel diameter of MCM-41. Optical properties of these heterostructured materials Ag-MCM-41 and Au-MCM-41 reveals the presence of surface plasmon absorption peaks of silver and gold respectively, and the shift in the absorption bands are associated to agglomeration of clusters inside the channels. Room temperature photoluminescence spectra exhibits interesting optical properties as observed for direct band gap semiconductors. Non-linear optical properties (NLO) corresponding to second harmonic generation (SHG) values were also recorded for self supported films of these heterostructured materials. Enhanced optical non-linearity was found to be arising from a corresponding increase of local field near the surface plasmon resonance. Further enhancement in SHG was found with poling due to an induction of orientation order.
Simple photometric determination of free cyanide ion in aqueous solution with 2,6-dichlorophenolindophenol
Authors: Yari Abdollah , Kargosha Kazem
Published: June 2006

In this work, a simple photometric method with high accuracy and precision for measuring trace amounts of free cyanide ion in aqueous solution is demonstrated. Under the evaluated conditions, we could determine CN− concentration in the range of 5–70 ppm easily. The work is based upon the photometric titration of CN− with Co(II) in the presence of 2,6-dichlorophenolindophenol (DCPIP) at λmax = 602 nm in aqueous solution. The optimal conditions, such as pH, ionic strength, and concentration of chromopher were evaluated. The interence effect of many other cations and anions studied and the results are given here. The optimized titration was successfully used to determine the concentration of free cyanide ion in aqueous solutions.
Partially nanowire-structured TiO2 electrode for dye-sensitized solar cells
Authors: Suzuki Yoshikazu , Ngamsinlapasathian Supachai , Yoshida Ryuhei , Yoshikawa Susumu
Published: June 2006

Partially nanowire-structured TiO2 was prepared by a hydrothermal processing followed by calcination in air. The hydrogen titanate powder as-synthesized was calcined at 300 °C for 4 h to obtain the partially nanowire-structured TiO2. A dye-sensitized solar cell (DSC) with a film thickness of 5.6 μm, fabricated using the partially nanowire-structured TiO2 showed better performance than using a fully nanowire-structured TiO2 or a conventional equi-axed TiO2 nanopowder. The short-circuit current density (JSC), the open-circuit voltage (VOC), the fill factor (FF) and the overall efficiency (η) are 11.9 mA/cm2, 0.754 V, 0.673 and 6.01 %, respectively. The effects of one-dimensional nanostructure and electron expressway concept are discussed.
Solid-state IR-LD spectroscopy of codeine and N-norcodeine derivatives
Authors: Bakalska Rumyana , Ivanova Bojidarka , Kolev Tsonko
Published: June 2006

Linear-dichroic infrared spectra (IR-LD) of 3-ethoxy-4-(N-norcodeino-)cyclobutene-1,2-dione (1) and codeine dihydrogenphosphate (Codeinum phosphoricum) (2), oriented as solid suspensions in nematic liquid crystals, have been measured. IR characteristic band assignments were made, and used in stereo-structural predictions. The results were compared with crystallographic structures of similar organic systems, and found to be in good agreement.
Accelerating the convergence of trigonometric series
Authors: Nersessian Anry , Poghosyan Arnak
Published: June 2006

A nonlinear method of accelerating both the convergence of Fourier series and trigonometric interpolation is investigated. Asymptotic estimates of errors are derived for smooth functions. Numerical results are represented and discussed.
Changes of thermal, mechanical and magnetic properties of an amorphous Fe80Cr5B15 alloy during magnetic and structural phase transitions
Authors: Kamasa Paweł , Myśliński Piotr
Published: June 2006

Thermal, mechanical and thermomagnetic properties associated with the magnetic and structural transition of an amorphous Fe80Cr5B15 alloy are described. The investigation was carried out in a simultaneous dilatometric and thermomagnetic experiment. An anomaly of the thermal expansion coefficient at the Curie point and a change in mechanical properties just before the onset of crystallization are observed. The results are compared with the thermal behavior obtained by differential scanning calorimetry.
The possibility of time resonance (explosion) phenomena in high-energy nuclear reactions
Authors: Olkhovsky Vladislav , Dolinska Marina , Omelchenko Sergey
Published: June 2006

This study shows that the exponential decrease of the energy spectra, accompanied by slight oscillations, with final-fragment energy in high-energy nuclear reaction, and independent of fragments, targets, projectiles, and projectile energies, can be explained under some conditions in the range of strongly overlapping compound resonances by a new phenomenon of time resonances (explosions). These time resonances (explosions) correspond to the formation of a few highly-excited, non-exponentially decaying nuclear clots (partial compound nuclei consisting of certain small groups of target and projectile nucleons). The proposed approach is an alternative way of analyzing experimental data compared with the majority of known descriptions (for instance, fireball models). This is a new and more general version of the time-evolution approach compared with the Izumo-Araseki time compound-nucleus model.
Rapidly rotating Bose-Einstein condensates in anharmonic confinement
Authors: Lu Li-Hua , Li You-Quan
Published: June 2006

We study a rapidly rotating Bose-Einstein condensate in anharmonic confinement and find that many properties, such as the critical rotating frequency and phase diagram, are different from those in a harmonic trap. We investigate the phase transitions between various vortex lattices and find that a hole emerges in the center of the cloud when the rotating frequency Θ reaches Θh but it becomes invisible when Θ > 1.0842ω
⊥.
Quantum states with Space-like energy-momentum
Authors: Solomon Dan
Published: June 2006

A common assumption in quantum field theory is that the energy-momentum 4-vector of any quantum state must be time-like. It will be proven that this is not the case for a Dirac-Maxwell field. In this case quantum states can be shown to exist whose energy-momentum is space-like.
Simulating a perpendicular exchange-biased structure with a partially covering nonmagnetic insertion at the FM/AFM interface
Authors: Błlachowicz Tomasz
Published: June 2006

The existence of minority spins, opposite to the perpendicular exchange bias, and majority spins aligned with this bias, and the dependence of the perpendicular exchange-bias field on the imprint effect, caused by the partially covering spacer at the ferromagnetic/antiferromagnetic (FM/AFM) interface, have been studied using Ising-type simulations. The present investigation suggests that the main factors influencing this phenomenon were dependent on the FM/AFM interface morphology, the balance between FM/AFM coupling and the FM-spins coupling, and the numerical balance between minority and majority spins. It was also determined that the imprint phenomenon can be used to enhance the perpendicular exchange-bias for small partial insertions at the FM/AFM interface.
Hydrogels in Biology and Medicine: From Molecular Principles to Bionanotechnology
Authors: Peppas N. A. , Hilt J. Z. , Khademhosseini A. , Langer R.
Published: May 2006

Hydrophilic polymers are the center of research emphasis in nanotechnology because of their perceived “intelligence”. They can be used as thin films, scaffolds, or nanoparticles in a wide range of biomedical and biological applications. Here we highlight recent developments in engineering uncrosslinked and crosslinked hydrophilic polymers for these applications. Natural, biohybrid, and synthetic hydrophilic polymers and hydrogels are analyzed and their thermodynamic responses are discussed. In addition, examples of the use of hydrogels for various therapeutic applications are given. We show how such systems' intelligent behavior can be used in sensors, microarrays, and imaging. Finally, we outline challenges for the future in integrating hydrogels into biomedical applications.
Cover Picture: Using a Core–Sheath Distribution of Surface Chemistry through 3D Tissue Engineering Scaffolds to Control Cell Ingress (Adv. Mater. 11/2006)
Authors: Barry J. J. A. , Howard D. , Shakesheff K. M. , Howdle S. M. , Alexander M. R.
Published: May 2006

The cover image shows a section through a 3D microcomputed‐tomography reconstruction of a porous polymer tissue‐engineering scaffold. Fibroblast cells (red) are encouraged to populate the interior of the disc by using a core/sheath distribution of plasma polymer (pp) coating. The background shows the cells on a flat surface, where their preference for adhesion to the pp allylamine surface (left) adjacent to a pp hexane (right) surface is readily apparent. This report by Alexander and co‐workers on p. 1406 is the first of cellular guidance within porous scaffolds using plasma polymerization, a coating method readily transferable to other scaffold materials.
A DFT Study of the Molecular Mechanisms of the Nucleophilic Addition of Ester‐Derived Lithium Enolates and Silyl Ketene Acetals to Nitrones: Effects of the Lewis Acid Catalyst
Authors: Domingo Luis R. , Arnó Manuel , Merino Pedro , Tejero Tomás
Published: May 2006

The molecular mechanisms for the nucleophilic addition of lithium enolates and silyl ketene acetals to nitrones in the absence and in the presence of a Lewis acid (LA) catalyst to give isoxazolidin‐5‐ones or hydroxylamines have been investigated by DFT methods at the B3LYP/6‐31G* level. The addition of lithium enolates to nitrones gives the corresponding hydroxylamines, while the addition of silyl ketene acetals affords isoxazolidin‐5‐ones through a concerted 1,3‐dipolar cycloaddition. The addition of the silyl ketene acetals to LA‐coordinated nitrones yields isoxazolidin‐5‐ones by a polar concerted cycloaddition or a stepwise nucleophilic attack via zwitterionic intermediates. A silyl migration on the [3+2] cycloadduct yields the corresponding O‐silylhydroxylamine. An analysis of the global electrophilicity of the reagents accounts for the strong electrophile activation of the LA‐coordinated nitrone, and the analysis of the local indices leads to an explanation for the experimentally observed regioselectivity. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Do Serine Octamers Exist in Solution? Relevance of this Question in the Context of the Origin of Homochirality on Earth
Authors: Vandenbussche Sophie , Vandenbussche Guy , Reisse Jacques , Bartik Kristin
Published: May 2006

Recent MS studies have suggested that serine clusters could have played a role in the origin of homochirality on Earth. Aqueous serine solutions have been probed in order to see if serine clusters, such as those observed by MS, are present in solution. IR measurements as well as NMR chemical shift and diffusion coefficient measurements, as a function of pH and serine concentration, suggest that these clusters do not exist in solution. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2006)
Using size exclusion chromatography‐RPLC and RPLC‐CIEF as two‐dimensional separation strategies for protein profiling
Authors: Simpson David C. , Ahn Seonghee , Pasa‐Tolic Ljiljana , Bogdanov Bogdan , Mottaz Heather M. , Vilkov Andrey N. , Anderson Gordon A. , Lipton Mary S. , Smith Richard D.
Published: May 2006

Bottom‐up proteomics (analyzing peptides that result from protein digestion) has demonstrated capability for broad proteome coverage and good throughput. However, due to incomplete sequence coverage, this approach is not ideally suited to the study of modified proteins. The modification complement of a protein can best be elucidated by analyzing the intact protein. 2‐DE, typically coupled with the analysis of peptides that result from in‐gel digestion, is the most frequently applied protein separation technique in MS‐based proteomics. As an alternative, numerous column‐based liquid phase techniques, which are generally more amenable to automation, are being investigated. In this work, the combination of size‐exclusion chromatography (SEC) fractionation with RPLC‐Fourier‐transform ion cyclotron resonance (FTICR)‐MS is compared with the combination of RPLC fractionation with CIEF‐FTICR‐MS for the analysis of the Shewanella oneidensis proteome. SEC‐RPLC‐FTICR‐MS allowed the detection of 297 proteins, as opposed to 166 using RPLC‐CIEF‐FTICR‐MS, indicating that approaches based on LC‐MS provide better coverage. However, there were significant differences in the sets of proteins detected and both approaches provide a basis for accurately quantifying changes in protein and modified protein abundances.
Capillary electrophoresis of affinity complexes between subviral 80S particles of human rhinovirus and monoclonal antibody 2G2
Authors: Kremser Leopold , Petsch Martina , Blaas Dieter , Kenndler Ernst
Published: May 2006

Human rhinoviruses (HRVs), the main etiologic agents of the common cold, transform into subviral B‐ or 80S particles (they sediment at 80S upon sucrose density gradient centrifugation) during infection and, in vitro, upon exposure to a temperature between 50 and 56°C. With respect to the native virion they lack the genomic RNA and the viral capsid protein VP4. 80S particles are unstable and easily disintegrate into their components, VP1, VP2, and VP3 in buffers containing SDS. However, this detergent was found to be a necessary constituent of the BGE for the analysis of these viruses and their complexes with receptors and antibodies by CE. We here demonstrate that dodecylpoly(ethyleneglycol ether) (D‐PEG) a nonionic detergent, is suitable for analysis of subviral particles as it preserves their integrity, in contrast to SDS. Electrophoresis of the 80S particles in borate buffer (pH 8.3, 100 mM) containing 10 mM D‐PEG resulted in a well‐defined electrophoretic peak. The identity of the peak was confirmed, among other means, by complexation with mAb 2G2, which recognizes a structural epitope exclusively present on subviral particles but not on native virus. Upon incubation of the 80S particles with mAb 2G2 the peak disappeared, but a new peak, attributed to the antibody complex emerged. The separation system allowed following the time course of the transformation of intact HRV serotype 2 into 80S particles upon incubation at temperatures between 40 and 65°C. We also demonstrate that subviral particles derived from HRV2 labeled with the fluorescence dyes FITC or Cy3.5 were stable in the separation system containing D‐PEG. Dye‐modified particles were still recognized by mAb 2G2, suggesting that the exposed lysines that are derivatized by the reagent do not form part of the epitope of the antibody.
Hexagonally‐closed‐packed micro‐light‐emitting diodes
Authors: Choi H. W. , Chua S. J.
Published: May 2006

A micro‐light‐emitting diode array, based on a hexagonal closed‐packed structure is presented. Compared to previous designs such as microdisk and microring, the packing density of individual hexagonal elements can be increased to over 80% to minimize wastage of junction area. The increased sidewall area provides additional light extraction pathways. The hexagonal LED emits twice as much light compared to a conventional broad‐area LED with equal junction area, and 50% more light than a microdisk array LED. The marked improvement in efficiency makes the additional processing step worthwhile. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Doping efficiency and segregation of Si in AlN grown by molecular beam epitaxy
Authors: Lebedev V. , Morales F. M. , Romanus H. , Ecke G. , Cimalla V. , Himmerlich M. , Krischok S. , Schaefer J. A. , Ambacher O.
Published: May 2006

The growth of Si‐doped 2H‐AlN thin films by plasma‐induced molecular‐beam epitaxy is reported. We have found that Si positively affects the epitaxy being an effective surfactant for AlN growth with a remarkable impact on the crystal quality. It was also observed that heavy doping conditions result in the volume segregation of Si at the threading dislocation network and in the formation of an amorphous (AlO)(SiO)N cap layer caused by post‐growth surface oxidation of the accumulated Al and segregated Si. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
AlGaN films grown on trenched sapphire substrates using a low‐temperature GaNP buffer layer by MOCVD
Authors: Sumiyoshi K. , Tsukihara M. , Kawamichi S. , Yan F. , Sakai S.
Published: May 2006

A technique has been developed to grow low‐dislocation‐density AlGaN films in this paper. The AlGaN film is laterally overgrown on a trenched sapphire substrate with a low‐temperature (LT) GaNP buffer layer by metalorganic chemical vapour deposition (MOCVD). The optical charactertics and microstructure of the AlGaN films have been invesigated by means of cathodoluminescence (CL), high‐resolution X‐ray diffraction (HRXRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) techniques. It is shown that the dislocation densities in the Al0.07Ga0.93N film are reduced to 8.7 x 108 cm–2 (by CL) and 2.7 x 109 cm–2 (by TEM) in the whole trenched sapphire, and 4.0 x 108 cm–2 (by CL) and 1.3 x 109 cm–2 (by TEM) in the trenched area. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Resonant photoluminescence excitation studies of InGaN/GaN single quantum wells
Authors: Graham D. M. , Dawson P. , Godfrey M. J. , Kappers M. J. , Barnard J. S. , Humphreys C. J. , Thrush E. J.
Published: May 2006

The optical properties of InGaN/GaN single quantum well structures, with indium fractions of 0.15 and 0.25, have been studied under resonant excitation conditions. The low temperature (T = 6 K) photoluminescence spectra show a broad recombination feature that we attribute to acoustic phonon accompanied absorption and emission from a distribution of localized states. Also we observe in the sample with the indium fraction of 0.15 a sharp line that we attribute to LO phonon accompanied recombination of excitons in the resonantly excited localized states. Comparing the form of the spectra with model calculations, where we consider the deformation potential coupling of localized excitons to an effectively continuous distribution of acoustic phonons, enables us to show that the in‐plane localization length scale of the excitons may be as small as 2.5 Å. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Performance of AlGaN/GaN heterojunction FETs for microwave power applications
Authors: Miyamoto H.
Published: May 2006

This paper describes design and performance of AlGaN/GaN heterojunction FETs for microwave power applications. A recessed‐gate FET with a field‐modulating plate (FP) was developed for high‐voltage power operation at L‐band and C‐band. The developed recessed FP‐FETs exhibited a 230‐W CW output power at 2 GHz and a 156‐W pulsed output power at 4 GHz. A T‐shaped 0.25‐μm‐gate FET was fabricated for high‐frequency power operation at Ka‐band. A 1.0‐mm‐wide FET exhibited a 5.8‐W CW output power at 30 GHz. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Fabrication of InN/AlInN MQWs by RF‐MBE
Authors: Terashima W. , Che S. B. , Ishitani Y. , Yoshikawa A.
Published: May 2006

We studied on the growth of N‐polarity InN/AlInN MQWs by radio frequency plasma‐assisted MBE. We found that the growth temperature greatly affected the structural properties of InN/AlInN MQWs. The growth temperature for achieving fine periodic MQWs was in the range from 550 to 580 °C. By optimizing the growth conditions, we for the first time successfully fabricated InN‐based MQWs with AlxIn1–xN (∼0.2 < x < ∼0.3) barrier layers. Clear satellite peaks up to the 3rd order in high resolution X‐ray diffraction were observed, indicating that being fine periodic MQWs‐structures with fairly flat and sharp interfaces. Photoluminescence peaks ranging from 0.68 to 0.99 eV were observed depending on the well thickness and they were in good agreement with those estimated by simple theoretical calculation. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Band‐to‐band and inner shell excitation VIS‐UV photoluminescence of quaternary InAlGaN alloys
Authors: Fukui K. , Naoe S. , Okada K. , Hamada S. , Hirayama H.
Published: May 2006

Visible and ultraviolet photoluminescence and photoluminescence excitation spectra of quaternary InAlGaN alloys were measured. The excitation photon energy covers from band edge to 180 eV, near both nitrogen K (∼400eV) and aluminium K (∼1.5 keV) inner shell energy region. From photoluminescence excitation spectra photoluminescence intensity per incident photon number varies in proportion to incident photon energy. This result implies that many conduction band electron ‐ valence band hole pairs which are responsible for photoluminescence are produced by high energy excitation. Time resolved decay curves were also measured in the same energy region. No effect of high energy excitation on time resolved decay measurements suggests a role of indium on the photoluminescence mechanism in InAlGaN system. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Photoluminescence spectra of GaN films grown at low temperature by compound‐source molecular beam epitaxy
Authors: Honda Tohru , Sawada Masaru , Kobayashi Toshiaki , Egawa Shinichi , Aoki Yohta , Akiyama Miwako , Kawanishi Hideo
Published: May 2006

The photoluminescence spectra of GaN films deposited by compound‐source molecular beam epitaxy (CS‐MBE) at 450 °C are reported. A near band‐edge emission was observed from the GaN layers grown on (0001) 6H‐SiC substartes by CS‐MBE at 18 K. The cathodoluminescence spectra of the deposited films and GaN powders were also observed at 20 K. The emission intensity per film thickness of the deposited films is roughly the same as that of GaN powders. Electroluminescent devices were fabricated using the deposited films, and a UV light emission was observed from these devices. (© 2006 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Synthese, Kristallstruktur und magnetisches Verhalten von Gd(CF3CF2COO)3(H2O)3
Authors: Rohde Alexander , Urland Werner
Published: May 2006

Synthesis, Crystal Structure and Magnetic Behaviour of Gd(CF3CF2COO)3(H2O)3

Single crystals of Gd(CF3CF2COO)3(H2O)3 have been obtained by reaction of Gd2O3 with an aqueous solution of CF3CF2COOH. The compound crystallizes triclinically in the space group $P{\bar 1}$ (No. 2; Z = 2; a = 928.5(1) pm, b = 1037.1(1) pm, c = 1147.3(2) pm, α = 90.44(2)°, β = 108.56(1)°, γ = 106.49(1)°). In the crystal structure the gadolinium ions are bridged by carboxylate groups to dimers and are coordinated eightfold by oxygen atoms. The magnetic behaviour was investigated in the temperature range of 1.77 to 300 K. The magnetic data indicate weak antiferromagnetic interactions within the dimeric unit (Jex = −0.0057 cm−1).
Synthesen, Eigenschaften und Kristallstrukturen der Cluster‐Salze Bi6[PtBi6Cl12] und Bi2/3[PtBi6Cl12]
Authors: Hampel Silke , Ruck Michael
Published: May 2006

Syntheses, Properties and Crystal Structures of the Cluster Salts Bi6[PtBi6Cl12] and Bi2/3[PtBi6Cl12]

Melting reactions of Bi with Pt and BiCl3 yield shiny black, air insensitive crystals of the subchlorides Bi6[PtBi6Cl12] and Bi2/3[PtBi6Cl12]. Despite the substantial difference in the bismuth content the two compounds have almost the same pseudo‐cubic unit cell and follow the structural principle of a CsCl type cluster salt. Bi6[PtBi6Cl12] consists of cuboctahedral [PtBi6Cl12]2− clusters and Bi62+ polycations (a = 9.052(2) Å, α = 89.88(2)°, space group P 1, multiple twins). In the electron precise cluster anion, the Pt atom (18 electron count) centers an octahedron of Bi atoms whose edges are bridged by chlorine atoms. The Bi62+ cation, a nido cluster with 16 skeletal electrons, has the shape of a distorted octahedron with an opened edge. In Bi2/3[PtBi6Cl12] the anion charge is compensated by weakly coordinating Bi3+ cations which are distributed statistically over two crystallographic positions (a = 9.048(2) Å, α = 90.44(3)°, space group $R{\bar 3}$). Bi6[PtBi6Cl12] is a semiconductor with a band gap of about 0.1 eV. The compound is diamagnetic at room temperature though a small paramagnetic contribution appears towards lower temperature.
La4N2S3: Ein neues Nitridsulfid des Lanthans mit beispielloser Kristallstruktur
Authors: Lissner Falk , Schleid Thomas
Published: May 2006

La4N2S3: A New Nitride Sulfide of Lanthanum with Unprecedented Crystal Structure

The oxidation of lanthanum powder with sulfur and cesium azide (CsN3) in the presence of lanthanum tribromide (LaBr3) yields lanthanum nitride sulfide with the composition La4N2S3 when appropriate molar ratios of the reactants are used. Additional cesium bromide (CsBr) as a flux secures fast reactions (7 d) at 900 °C in evacuated silica tubes as well as the formation of almost black single crystals. The orthorhombic crystal structure (Pnnm, Z = 2) was determined from single crystal X‐ray diffraction data (a = 641.98(4), b = 1581.42(9), c = 409.87(3) pm). Two crystallographically different La3+ cations are present, La1 resides in sixfold coordination of two N3− and four S2− anions forming a trigonal prism and La2 is coordinated by two N3− and five S2− in the shape of a monocapped trigonal prism. However, the main feature of the crystal structure comprises N3−‐centred (La3+)4 tetrahedra which arrange as pairs [N2La6]12+ of edge‐shared [NLa4]9+ units and which are further connected via four vertices to form double chains $^{1}_{\infty}\rm \{[N_{2}La_{2}La^{\prime}_{4/2}]^{6+}\}$. They get bundled along [001] like a hexagonal rod packing and are held together by two crystallographically different S2− anions. Further motifs for the connectivity of [NM4]9+ tetrahedra in crystal structures of nitride chalcogenides and halides of the rare‐earth elements (M = Sc, Y, La; Ce – Lu) with ratios of N : M = 1 : 2 are presented and discussed for comparison.
Li6+2x[B10Se18]Sex (x ≈ 2), ein ionenleitendes Doppelsalz
Authors: Hammerschmidt A. , Döch M. , Pütz S. , Eckert H. , Krebs B.
Published: May 2006

Li6+2x[B10Se18]Sex (x ≈ 2), an Ion‐conducting Double Salt

Li6+2x[B10Se18]Sex (x ≈ 2) was prepared in a solid state reaction from lithium selenide, amorphous boron and selenium in evacuated carbon coated silica tubes at a temperature of 800 °C. Subsequent cooling from 600 °C to 300 °C gave amber colored crystals with the following lattice parameters: space group I2/a (at 173 K); a = 17.411(1) Å, b = 21.900(1) Å, c = 17.820(1) Å, β = 101.6(1)°. The crystal structure contains a well‐defined polymeric selenoborate network of composition ([B10Se16Se4/2]6−)n consisting of a system of edge‐sharing [B10Se16Se4/2] adamantanoid macro‐tetrahedra forming large channels in which a strongly disorderd system of partial occupied Li+ cations and additional disordered Se2− anions is observed. The crystal structure of the novel selenoborate is isotypic to Li6+2x[B10S18]Sx (x ≈ 2) [1]. X‐ray and 7Li magic‐angle spinning NMR data suggest that the site occupancies of the three crystallographically distinct lithium ions exhibit a significant temperature dependence. The lithium ion mobility has been characterized by detailed temperature dependent NMR lineshape and spin‐lattice relaxation measurements.
Die Aluminidiodide La24Al12I21 und La10Al5I8: Verbindungen mit intermetallischen La‐Al‐Bereichen und La‐Al‐Clustern
Authors: Mattausch Hansjürgen , Oeckler Oliver , Hoch Constantin , Simon Arndt
Published: May 2006

The Aluminide Iodides La24Al12I21 and La10Al5I8: Compounds with Intermetallic La‐Al Fractions and La‐Al Clusters

Reacting pieces of La, LaI3 and Al filings (molar ratio 22 : 8 : 15) at 800 °C–825 °C results in La24Al12I21 (70 % yield) together with La10Al5I8 (10 % yield), besides known La3Al2I2 and La2Al2I. Both new compounds form golden coloured needles. La10Al5I8 is brittle, whereas La24Al12I21 is shaped as hair‐like easily deformable bundles. Both are monoclinic, space group C2/m, La24Al12I21 with a = 35.753(7) Å, b = 4.327(1) Å, c = 27.442(6) Å, β = 116.62(3)° and La10Al5I8 with a = 19.649(1) Å, b = 4.296(1) Å, c = 18.0290(1) Å and β = 96.67(3)°. The La atoms form trigonal prisms condensed into double chains along [010]. The La prisms are centered by Al atoms which form Al6 rings connected into chains. The La‐Al strands are surrounded by I atoms in La24Al12I21, whereas in La10Al5I8 they are connected to form corrugated sheets separated by close packed layers of I atoms together with Al atoms. The octahedral voids around the Al atoms are occupied by La atoms, and such La6Al clusters are connected via opposite edges to octahedra chains along [010].
Rhenium‐Dicarbonyl‐Nitrosyl‐Komplexe mit Imidazol
Authors: Rattat Dirk , Verbruggen Alfons , Berke Heinz
Published: May 2006

Rhenium Dicarbonyl‐Nitrosyl Complexes with Imidazole

Different rhenium‐dicarbonyl‐nitrosyl complexes with imidazole (Im) as monodentate ligand have been synthesized and characterized, starting from [NEt4][ReCl3(CO)2(NO)] and [ReCl(μ−Cl)(CO)2(NO)]2. Whereas the complexes [ReCl2(Im)(CO)2(NO)] and [ReCl(Im)2(CO)2(NO)]+ were achieved in high yields, the complex [Re(Im)3(CO)2(NO)]2+ with three imidazole ligands could only be isolated after complete removal of all halide ions (with AgBF4) in low yield. The synthesis of a corresponding 99mTc‐dicarbonyl‐nitrosyl complex with imidazole opens a new perspective for such compounds as potential radiopharmaceuticals and alternatives to the already established 99mTc‐tricarbonyl complexes.
A New Europium(II) Oxide Iodide: Eu2OI2
Authors: Hammerich Stefanie , Meyer Gerd
Published: May 2006

Red single crystals of Eu2OI2 were obtained from a reaction mixture of barium metal, EuI2, Eu4OI6 and some NH4I in a tantalum tube at 780/500 °C. The crystal structure (orthorhombic, Imcb, Z = 4, a = 648.93(11), b = 742.85(13), c = 1307.1(3) pm, R1(all) = 0.0605) contains {Eu4O} tetrahedra connected via trans‐edges to infinite chains. The iodide ions surround and connect these chains to a three‐dimensional structure.
The Structural Systematics of Protonation of Some Important Nitrogen‐base Ligands. III. Some (Univalent) Anion Salts of some Hindered Unidentate Nitrogen Bases
Authors: Effendy  , Junk Peter C. , Kepert Cameron J. , Louis Lance M. , Morien Travis C. , Skelton Brian W. , White Allan H.
Published: May 2006

Recent structural studies of salts of the 2,2,6,6‐tetramethylpiperidinium cation [tmpH]+ (chloride, bromide; thiocyanate) present as interesting dimeric or polymeric associations linked by pairs of directional hydrogen‐bonds from the cationic = ${\rm NH}^{+}_{2}$ moieties to ‘two‐coordinate’ anions. Present single crystal X‐ray studies have characterized the iodide, perchlorate, nitrate and trifluoroacetate complexes, all, like those of the preceding studies, of composition [tmpH]+X− (anhydrous). A variety of forms are found: the nitrate compound is dimeric [[tmpH](O·NO·O)2[Htmp]], the trifluoroacetate compound being similar in form while the iodide and perchlorate salts are mixtures of dimers (with the anions essentially single atom bridges) and single‐stranded helical polymers, the stoichiometric ratio of these being 1:1 and 2:1 in terms of [tmpH]X formula units, respectively. A study of 4‐keto‐2,2,6,6‐tetramethyl‐piperidinium thiocyanate shows it to be a dimer $\left [ [{\rm OtmpH}] \left (^{\rm SCN}_{\rm NSC} \right ) [{\rm HtmpO}] \right ]$ unlike its previously studied chloride analogue which is a cyclic tetramer. A new P21/n phase of di‐isopropylammonium chloride, derivative of the previously described P212121 and P21 forms, is reported, together with descriptions of protonated salts of the other hindered unidentate bases 2,6‐lutidine (as the chloride salt), quinoline (as the perchlorate, trifluoroacetate, hexachlorostannate and bisulfate salts) and 2‐quinaldine (as the chloride (anhydrous and monohydrate) and hexachlorostannate salts), all displaying arrays derivative of ion‐pair formation (extended by anion‐anion hydrogen‐bonds as well in the bisulfate salt) and, in the case of the aromatic bases, dominated by parallel stacking.
The Structural Systematics of Protonation of Some Important Nitrogen‐Base Ligands. V. Some Univalent Anion Salts of Mono‐ and Bis(2‐picolyl)amine
Authors: Junk Peter C. , Kim Yang , Skelton Brian W. , White Allan H.
Published: May 2006

A variety of salts derivative of bis(2‐picolyl)amine, ‘dipic’ = [{(C5NH4)(CH2)}2NH] in various stages of protonation have been structurally characterized, showing a considerable diversity of hydrogen‐bonding modes and interactions. For the triprotonated species (protonating hydrogen atoms on all three nitrogen atoms) the arrays are haphazard ([picH3]X3, X = Cl(·H2O), I(·H2O), NO3, tfs (= trifluoromethanesulfonate)(·H2O). For the diprotonated species, diverse forms are also found: in [dipicH2]Br2, the central nitrogen atom and one of the peripheral are protonated, but in the remainder, both peripheral nitrogen atoms are protonated, leading to a propensity to chelating interactions with an anion (as in the mixed anion salts ${\rm CL}^{-}\cdot{\rm I}^{-}_{3}$ and ${\rm I}^{-}\cdot{\rm I}^{-}_{3}$, where ${\rm I}^{-}_{3}$ does not interact) or a water molecule (in the I·2H2O salt) or anion (in the tfs salt) oxygen atom; in the nitrate salt, the ligand is twisted so that each pyridinium component interacts with an independent nitrate. By contrast, in the singly protonated species, [dipicH]X, the central nitrogen atom is protonated in all cases (X = Br, I, ClO4, thf). The tfs− salt is remarkable, containing a pair of cations with self‐interactions. In [picH]X only the aliphatic nitrogen is protonated (X = I−, ${\rm NO}^{-}_{3}$, ${\rm ClO}^{-}_{4}$, tfa− (= trifluoroacetate)). A single example of a diprotonated species [picH2]Cl2 has also been defined.
The Coordination Chemistry of Iron with the 1,4‐Bis(2‐pyridyl‐methyl)piperazine Ligand
Authors: Ostermeier Marc , Limberg Christian , Ziemer Burkhard
Published: May 2006

The behaviour of FeII and FeIII ions in combination with the potential ligand 1,4‐bis(2‐pyridyl‐methyl)piperazine (BPMP) under anhydrous conditions has been investigated. BPMP has been reacted with FeCl2, FeCl3 and [Fe(OTf)2(MeCN)2]. This led to the isolation of four new complexes, which were fully characterized and structurally investigated by single crystal X‐ray diffraction. It turned out that in the presence of chloride co‐ligands FeIII favours the tetradentate coordination mode of BPMP with the piperazine unit in a boat configuration, like for instance in [BPMP(Cl)Fe(μ‐O)FeCl3] or [BPMP‐FeCl2][FeCl4], (1). However, the employment of FeCl2 leads to the formation of a coordination polymer [BPMP‐FeCl2]n, (2), containing the piperazine ring in a chair configuration binding to two iron centres each. 2 can only be dissolved in very polar solvents like dmf which is capable of breaking up the polymeric structure under formation of [Cl2(dmf)Fe(μ‐BPMP‐1κ2N,N:2κ2N,N))Fe(dmf)Cl2]·2 dmf, (3). In contrast, using [Fe(OTf)2(MeCN)2] instead of FeCl2 as the starting material leads to a mononuclear FeII complex with BPMP bound in the desirable tetradentate fashion: [BPMP‐Fe(OTf)2], (4). Unlike other complexes with tetradentate N/py ligands the two residual ligands in 4 are bound almost trans to each other with the potential to adopt a cis orientation under oxidising conditions, and it will be interesting to exploit its catalytic properties in future.
Vibrational Spectra of Cluster Anions. 2. Vibrational Spectra of Compounds with the Cluster Anions [E4]4−: M4E4 (M = K, Rb, Cs; E = Ge, Sn) and β‐Na4Sn4
Authors: Somer Mehmet , Aydemir Umut , Baitinger Michael , von Schnering Hans Georg
Published: May 2006

Vibrational spectra of the compounds M4E4 (M = K, Rb, Cs; E = Ge, Sn) and of β‐Na4Sn4 with the cluster anions [E4]4− were analysed based on the point group ${\bar 4}{\rm 3}m-T_{d}$ of isolated tetrahedranide units. The lower individual ${\bar 4}{\rm 2}m-D_{2d}$ symmetry of the anions in the real structure being more patterned and complex primarily affects the spectra of the tetrahedro‐tetragermanides. ν3(F2) clearly splits both in Raman and IR and in the case of K4Sn4 only in IR. Rb4Sn4 and Cs4Sn4 exhibit very simple spectra with three bands in Raman and one band in IR. The breathing mode ν1(A1) for the quasi isolated [E4]4− cluster appears only in the Raman spectrum and is hardly influenced by the structural environment and by the nature of the alkali metal cations: ν1(A1) = 274 cm−1 ([Ge4]4−) and 183‐187 cm−1 ([Sn4]4−), respectively. The calculated valence force constants fd(E–E) are: [Ge4]4−: fd = 0.89 Ncm−1 (K), 0.87 Ncm−1 (Rb), 0.86 Ncm−1 (Cs) and [Sn4]4−: 0.67 Ncm−1 (Na), 0.66 Ncm−1 (K), 0.67 Ncm−1 (Rb), 0.68 Ncm−1 (Cs). Both, the frequencies and the force constants fit well into the range previously reported.
Adolescents’ views of food and eating: Identifying barriers to healthy eating
Authors: Stevenson Clifford , Doherty Glenda , Barnett Julie , Muldoon Orla T. , Trew Karen
Published: May 2006

Contemporary Western society has encouraged an obesogenic culture of eating amongst youth. Multiple factors may influence an adolescent's susceptibility to this eating culture, and thus act as a barrier to healthy eating. Given the increasing prevalence of obesity amongst adolescents, the need to reduce these barriers has become a necessity. Twelve focus group discussions of single‐sex groups of boys or girls ranging from early to‐mid adolescence (N=73) were employed to identify key perceptions of, and influences upon, healthy eating behaviour. Thematic analysis identified four key factors as barriers to healthy eating. These factors were: physical and psychological reinforcement of eating behaviour; perceptions of food and eating behaviour; perceptions of contradictory food‐related social pressures; and perceptions of the concept of healthy eating itself. Overall, healthy eating as a goal in its own right is notably absent from the data and would appear to be elided by competing pressures to eat unhealthily and to lose weight. This insight should inform the development of future food‐related communications to adolescents.
Prognostic role of myocardial tumor necrosis factor‐alpha and terminal complement complex expression in patients with dilated cardiomyopathy
Authors: Zimmermann Oliver , Kochs Matthias , Zwaka Thomas P. , Bienek‐Ziolkowski Magdalena , Höher Martin , Hombach Vinzenz , Torzewski Jan
Published: May 2006

Background:

In patients with dilated cardiomyopathy (DCM), elevated plasma levels of tumor necrosis factor‐α (TNF‐α) are associated with poor prognosis. The terminal complement complex (C5b‐9) stimulates myocardial TNF‐α expression.

Aims:

To investigate whether myocardial TNF‐α and C5b‐9 expression correlate with clinical outcome in DCM.

Methods and results:

71 patients with DCM underwent myocardial biopsy. Biopsies were analyzed for TNF‐α, C5b‐9, markers of inflammation and for viral genome. Patients were divided into three groups according to biopsy results: group A: no TNF‐α and no C5b‐9; group B: TNF‐α or C5b‐9; and group C: TNF‐α and C5b‐9. NYHA classification, ECG and echocardiography were documented. Patients received conventional treatment of heart failure and, in a few cases, additional treatment with interferon β1b (virus positive) or prednisolone (inflammatory DCM).

There were 13 patients (18%) in group A, 19 patients (27%) in group B, and 39 patients (55%) in group C. All groups had a similar and significant improvement in NYHA classification and echocardiographic parameters. TNF‐α and C5b‐9 did not significantly correlate with the presence of viral genome or with markers of inflammation.

Conclusion:

TNF‐α and C5b‐9 are widely distributed in the myocardium of DCM patients. Neither of the antigens correlates with clinical outcome. Myocardial TNF‐α may not be a useful prognostic marker in DCM.
Identification of microRNAs from different tissues of chicken embryo and adult chicken
Authors: Xu Hongtao , Wang Xiaobo , Du Zhenglin , Li Ning
Published: May 2006

We report for the first time the identification of 25 microRNAs from tissues originating from chicken embryo and adult chicken. Most of the cloned microRNAs are expressed in both adult chickens and chicken embryos. Fourteen were identified without any prior prediction. One microRNA, miR‐757, is thought to be chicken‐specific. Three of the microRNAs appear to be extremely tissue specific.
A multiproxy environmental investigation of Holocene wood from a submerged conifer forest in Lake Huron, USA
Authors: Hunter R. Douglas , Panyushkina Irina P. , Leavitt Steven W. , Wiedenhoeft Alex C. , Zawiskie John
Published: May 2006

Remains of a Holocene drowned forest in southern Lake Huron discovered in 12.5 m of water (164 m above sea level), 4.5 km east of Lexington, Michigan USA (Sanilac site), provided wood to investigate environment and lake history using several proxies. Macrofossil evidence indicates a forest comprised primarily of conifers equivalent to the modern “rich conifer swamp” community, despite generally low regional abundance of these species in pollen records. Ages range from 7095 ± 50 to 6420 ± 70 14C yr BP, but the clustering of stump dates and the development of 2 floating tree-ring chronologies suggest a briefer forest interval of no more than c. 400 years. Dendrochronological analysis indicates an environment with high inter-annual climate variability. Stable-carbon isotope composition falls within the range of modern trees from this region, but the stable-oxygen composition is consistent with warmer conditions than today. Both our tree-ring and isotope data provide support for a warmer environment in this region, consistent with a mid-Holocene thermal maximum. This drowned forest also provides a dated elevation in the Nipissing transgression at about 6420 14C yr BP (7350 cal yr BP) in the southern Lake Huron basin, a few hundred years before reopening of the St. Clair River drainage.
An evaluation of National and State policy and procedures for the prevention of the importation of weeds into Australian rangelands
Authors: Jacob Helen Spafford , Randall Rod
Published: May 2006

Australia’s rangelands are under pressure from many sources, not the least of which is exotic plants often intentionally introduced as pasture or fodder crops. Before being intentionally introduced into Australia, a plant must pass a weed risk assessment administered by Biosecurity Australia. In addition, there are checks by Australian Quarantine and Inspection Service of shipments and international mail before it is allowed entry into Australia, restricting the unintentional and illegal introduction of plants. However, there are many ways in which plants can bypass these procedures and once inside Australia there is little to prevent these plants moving from state to state. Closing these gaps at the international borders and developing effective policies to deal with interstate movement of plants is essential to reduce the impacts of weeds on biodiversity, pastoral activities and other uses of Australian rangelands. This paper highlights these issues and provides recommendations to correct the problems.