bluuebunny/crossref_metadata_2025 huggingface dataset:
SEAR: a secure efficientad hocon demand routing protocol for wireless networks
Authors: Li Qing , Zhao Meiyuan , Walker Jesse , Hu Yih‐Chun , Perrig Adrian , Trappe Wade
Published: September 2008

Multi‐hop routing is essential to the operation of wirelessad hocnetworks. Unfortunately, it is very easy for an adversary to forge or modify routing messages to inflict severe damage on the underlying routing protocol. In this paper, we present SEAR, a secure efficientad hocrouting (SEAR) protocol forad hocnetworks that is mainly based on efficient symmetric cryptography, with asymmetric cryptography used only for the distribution of initial key commitments. SEAR uses one‐way hash functions to protect the propagation of the routing messages. Intermediate nodes verify the routing messages by applying one‐way functions, while malicious nodes cannot construct beneficial false routing messages when forwarding them. Route error (RERR) messages are protected through a variation of the TESLA broadcast authentication scheme. The SEAR protocol does not require any additional routing packet formats, and thus follows the same basic design asad hocon‐demand distance vector (AODV). We show, through both theoretical examination and simulations, that SEAR provides better security with significantly less overhead than other existing secure AODV (SAODV) protocols. Copyright © 2008 John Wiley & Sons, Ltd.
Biomarker discovery using targeted maximum‐likelihood estimation: Application to the treatment of antiretroviral‐resistant HIV infection
Authors: Bembom Oliver , Petersen Maya L. , Rhee Soo‐Yon , Fessel W. Jeffrey , Sinisi Sandra E. , Shafer Robert W. , van der Laan Mark J.
Published: September 2008

Researchers in clinical science and bioinformatics frequently aim to learn which of a set of candidate biomarkers is important in determining a given outcome, and to rank the contributions of the candidates accordingly. This article introduces a new approach to research questions of this type, based on targeted maximum‐likelihood estimation of variable importance measures.

The methodology is illustrated using an example drawn from the treatment of HIV infection. Specifically, given a list of candidate mutations in the protease enzyme of HIV, we aim to discover mutations that reduce clinical virologic response to antiretroviral regimens containing the protease inhibitor lopinavir. In the context of this data example, the article reviews the motivation for covariate adjustment in the biomarker discovery process. A standard maximum‐likelihood approach to this adjustment is compared with the targeted approach introduced here. Implementation of targeted maximum‐likelihood estimation in the context of biomarker discovery is discussed, and the advantages of this approach are highlighted. Results of applying targeted maximum‐likelihood estimation to identify lopinavir resistance mutations are presented and compared with results based on unadjusted mutation–outcome associations as well as results of a standard maximum‐likelihood approach to adjustment.

The subset of mutations identified by targeted maximum likelihood as significant contributors to lopinavir resistance is found to be in better agreement with the current understanding of HIV antiretroviral resistance than the corresponding subsets identified by the other two approaches. This finding suggests that targeted estimation of variable importance represents a promising approach to biomarker discovery. Copyright © 2008 John Wiley & Sons, Ltd.
Modeling the association of bivariate interval‐censored data using the copula approach
Authors: Bogaerts Kris , Lesaffre Emmanuel
Published: September 2008

In a survival study, it may not be possible to record the exact event time but only that the event has occurred between two time points or still has to occur, leading to interval‐censored survival times.

Recently, Sunet al.(Scand. J. Stat.2006;33(4):637–649) suggested to fit a Clayton copula with nonparametric marginal distributions to estimate the association for bivariate interval‐censored failure data. We propose here to model the marginal distributions with an accelerated failure time model with a flexible error term as suggested by Komáreket al.(J. Comput. Graph. Stat.2005;14(3):726–745) in combination with a one parameter copula. In addition, we allow the association parameter of the copula to depend on covariates.

The performance of our method is illustrated by an extensive simulation study and is applied to tooth emergence data of permanent teeth measured on 4468 children from a longitudinal dental study. Copyright © 2008 John Wiley & Sons, Ltd.
Strategies for analyzing multilevel cluster‐randomized studies with binary outcomes collected at varying intervals of time
Authors: Olsen Maren K. , DeLong Elizabeth R. , Oddone Eugene Z. , Bosworth Hayden B.
Published: September 2008

Frequently, studies are conducted in a real clinic setting. When the outcome of interest is collected longitudinally over a specified period of time, this design can lead to unequally spaced intervals and varying numbers of assessments. In our study, these features were embedded in a randomized, factorial design in which interventions to improve blood pressure control were delivered to both patients and providers. We examine the effect of the intervention and compare methods of estimation of both fixed effects and variance components in the multilevel generalized linear mixed model. Methods of comparison include penalized quasi‐likelihood (PQL), adaptive quadrature, and Bayesian Monte Carlo methods. We also investigate the implications of reducing the data and analysis to baseline and final measurements. In the full analysis, the PQL fixed‐effects estimates were closest to zero and confidence intervals were generally narrower than those of the other methods. The adaptive quadrature and Bayesian fixed‐effects estimates were similar, but the Bayesian credible intervals were consistently wider. Variance component estimation was markedly different across methods, particularly for the patient‐level random effects. In the baseline and final measurement analysis, we found that estimates and corresponding confidence intervals for the adaptive quadrature and Bayesian methods were very similar. However, the time effect was diminished and other factors also failed to reach statistical significance, most likely due to decreased power. When analyzing data from this type of design, we recommend using either adaptive quadrature or Bayesian methods to fit a multilevel generalized linear mixed model including all available measurements. Published in 2008 by John Wiley & Sons, Ltd.
Shrinkage stress analysis of concrete slabs in a multi‐storey building considering internal and external restraints
Authors: Kim Han‐Soo , Ahn Hyung‐Joon
Published: September 2008

Shrinkage strains of concrete slabs in a multi‐storey building are restrained internally by reinforcement bars as well as externally by supporting members such as columns or walls. These strains may induce tensile stresses in concrete members and lead to cracks due to excessive shrinkage stress. In this study, a practical shrinkage stress analysis method for application to concrete slabs in a multi‐storey building is proposed. The proposed approach considers both internal restraint of reinforcement bars and external restraint variations resulting from construction sequence. The shrinkage stress due to external restraint is obtained by multiplying the relaxation coefficient by the elastic shrinkage stress. The additional shrinkage stress due to internal restraint is obtained by the residual strain calculated via a linear elastic analysis for external restraints. A verification example was comparatively analysed using the proposed method and a commercially available analysis program that is capable of time‐dependent analysis of concrete. The results of a 10‐storey sample building suggest that the internal restraint due to reinforcement considerably increases the shrinkage stress at slabs under loose external restraint. Copyright © 2008 John Wiley & Son, Ltd.
An extract of Hydrilla verticillata and associated epiphytes induces avian vacuolar myelinopathy in laboratory mallards
Authors: Wiley Faith E. , Twiner Michael J. , Leighfield Tod A. , Wilde Susan B. , Van Dolah Frances M. , Fischer John R. , Bowerman William W.
Published: September 2008

Avian vacuolar myelinopathy (AVM) is a neurological disease affecting bald eagles (Haliaeetus leucocephalus), American coots (Fulica americana), waterfowl, and other birds in the southeastern United States. The cause of the disease is unknown, but is thought to be a naturally produced toxin. AVM is associated with aquatic macrophytes, most frequently hydrilla (Hydrilla verticillata), and researchers have linked the disease to an epiphytic cyanobacterial species associated with the macrophytes. The goal of this study was to develop an extraction protocol for separating the putative toxin from a hydrilla‐cyanobacterial matrix. Hydrilla samples were collected from an AVM‐affected reservoir (J. Strom Thurmond Lake, SC) and confirmed to contain the etiologic agent by mallard (Anas platyrhynchos) bioassay. These samples were then extracted using a solvent series of increasing polarity: hexanes, acetone, and methanol. Control hydrilla samples from a reference reservoir with no history of AVM (Lake Marion, SC) were extracted in parallel. Resulting extracts were administered to mallards by oral gavage. Our findings indicate that the methanol extracts of hydrilla collected from the AVM‐affected site induced the disease in laboratory mallards. This study provides the first data documenting for an “extractable” AVM‐inducing agent. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009.
Assessing the toxicity of herbicide isoproturon on Aporrectodea caliginosa (Oligochaeta) and its fate in soil ecosystem
Authors: Mosleh Yahia Youssef Ismail
Published: September 2008

This study was conducted to determine the residues of isoproturon and its metabolites, 1‐(4‐isopropylphenyl)‐3‐methylurea, 1‐(4‐isopropylphenyl) urea, and 4‐isopropylanilin in soil and mature earthworms under laboratory conditions. Mature earthworms (Aporrectodea caliginosa) were exposed for various durations (7, 15, 30, and 60 days) to soils contaminated with isoproturon concentrations (2, 4, 6, 8, and 10 mg kg−1 soil). The decrease in isoproturon concentration in the soil was inversely correlated to it's initial concentration. The highest concentration detected for isoproturon in earthworms was observed during the first 15 days and decreased thereafter. Acute toxicity of isoproturon was investigated; total soluble protein content and glycogen of the worms were evaluated. Levels of these parameters were related to isoproturon concentration in soil and earthworms. No lethal effect of isoproturon was observed even at the concentration of 1200 mg kg−1 soil after 60 days of exposure. A reduction of total soluble protein was observed in all treated worms (maximum 59.54%). This study suggests the use of the total soluble protein content and glycogen of earthworms as biomarkers of exposure to isoproturon. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009.
Folic acid or combination of folic acid and vitamin B12 prevents short‐term arsenic trioxide‐induced systemic and mitochondrial dysfunction and DNA damage
Authors: Majumdar Sangita , Mukherjee Sandip , Maiti Anasuya , Karmakar Subhra , Das Asankur Sekhar , Mukherjee Maitrayee , Nanda Arunabha , Mitra Chandan
Published: September 2008

The effect of folic acid and folic acid + vitamin B12 supplementation upon short‐term arsenic‐induced systemic and pancreatic islet cell mitochondria oxidative stress was investigated in male rats. Arsenic trioxide was administered orally at a dose of 3 mg kg body weight−1 day−1 for 30 days, and folic acid and vitamin B12 were administered at a dose of 36 and 0.63 μg kg body weight−1 day−1, respectively, for 30 days. Compared to control, arsenic‐treated group showed a significant increase in the levels of systemic oxidative markers, malondialdehyde (MDA), nitric oxide (NO), and hydroxyl radical (OH−) formation, which were found decreased significantly after supplementation either with folic acid or a combination of folic acid + vitamin B12. Similar supplementations were found effective against arsenic‐induced oxidative marker changes (MDA, NO, and OH−) in pancreatic islet cell mitochondria. Also, low activities of antioxidant defense enzymes such as superoxide dismutase and catalase, and level of antioxidant glutathione, all could regain significantly on supplementations both against systemic and islet cell mitochondria oxidative stress. Results of agarose‐gel electrophoresis of DNA from lymphocytes and islet cells of arsenic‐exposed rats showed DNA smearing, which could be reduced with simultaneous administration either with folic acid or a combination of folic acid + vitamin B12. Significantly, similar supplementations were found effective in increasing the urinary clearance of arsenic. Together, these results indicate that folic acid and vitamin B12 may be effective to reduce the arsenic‐induced damage at molecular target level. © 2008 Wiley Periodicals, Inc. Environ Toxicol, 2009.
Estimation of variability and predictability of large‐scale wind energy in The Netherlands
Authors: Gibescu Madeleine , Brand Arno J. , Kling Wil L.
Published: September 2008

This paper presents a data‐driven approach for estimating the degree of variability and predictability associated with large‐scale wind energy production for a planned integration in a given geographical area, with an application to The Netherlands. A new method is presented for generating realistic time series of aggregated wind power realizations and forecasts. To this end, simultaneous wind speed time series—both actual and predicted—at planned wind farm locations are needed, but not always available. A 1‐year data set of 10‐min averaged wind speeds measured at several weather stations is used. The measurements are first transformed from sensor height to hub height, then spatially interpolated using multivariate normal theory, and finally averaged over the market resolution time interval. Day‐ahead wind speed forecast time series are created from the atmospheric model HiRLAM (High Resolution Limited Area Model). Actual and forecasted wind speeds are passed through multi‐turbine power curves and summed up to create time series of actual and forecasted wind power. Two insights are derived from the developed data set: the degree of long‐term variability and the degree of predictability when Dutch wind energy production is aggregated at the national or at the market participant level. For a 7.8 GW installed wind power scenario, at the system level, the imbalance energy requirements due to wind variations across 15‐min intervals are ±14% of the total installed capacity, while the imbalance due to forecast errors vary between 53% for down‐ and 56% for up‐regulation. When aggregating at the market participant level, the balancing energy requirements are 2–3% higher. Copyright © 2008 John Wiley & Sons, Ltd.
Design of a wind turbine rotor for maximum aerodynamic efficiency
Authors: Johansen Jeppe , Madsen Helge Aa. , Gaunaa Mac , Bak Christian , Sørensen Niels N.
Published: September 2008

The design of a three‐bladed wind turbine rotor is described, where the main focus has been highest possible mechanical power coefficient, CP, at a single operational condition. Structural, as well as off‐design, issues are not considered, leading to a purely theoretical design for investigating maximum aerodynamic efficiency.

The rotor is designed assuming constant induction for most of the blade span, but near the tip region, a constant load is assumed instead. The rotor design is obtained using an actuator disc model, and is subsequently verified using both a free‐wake lifting line method and a full three‐dimensional Navier–Stokes solver.

Excellent agreement is obtained using the three models. Global CP reaches a value of slightly above 0.51, while global thrust coefficient CT is 0.87. The local power coefficient Cp increases to slightly above the Betz limit on the inner part of the rotor; the local thrust coefficient Ct increases to a value above 1.1. This agrees well with the theory of de Vries, which states that including the effect of the low pressure behind the centre of the rotor stemming from the increased rotation, both Cp and Ct will increase towards the root. Towards the tip, both Cp and Ct decrease due to tip corrections as well as drag. Copyright © 2008 John Wiley & Sons, Ltd.
Concentrations of essential and nonessential elements in shoots and storage roots of carrot grown in NaCl and Na2SO4 salinity
Authors: Inal Ali , Gunes Aydin , Pilbeam David J. , Kadioglu Yusuf K. , Eraslan Figen
Published: September 2008

This study was undertaken to examine the effects of NaCl and Na2SO4 salinity on the growth of carrot (Daucus carota L.) and the concentrations of essential and nonessential elements in the shoots and storage roots determined by polarized energy dispersive x‐ray fluorescence (PEDXRF). Both types of salinity reduced plant growth, but growth reduction in NaCl salinity was more pronounced. Na concentrations in shoots and roots were increased by salinity treatment. The concentration of Cl was also increased by NaCl salinity. Salinity treatments decreased K concentrations in the shoots and storage roots, and Ca concentrations in the shoots. Concentration of P in shoots and roots, and S, Mg, and Si in roots were not significantly affected by salinity treatments, while the NaCl salinity reduced S and Si and increased Mg concentrations in the shoots. Fe, Zn, Mn and Mo concentrations in the shoots were not significantly affected by salinity treatments. In the storage roots, the concentration of Fe was significantly increased by NaCl salinity, while Na2SO4 salinity significantly increased Zn and Mn concentrations in storage roots. Concentration of Al in the storage roots was significantly higher with NaCl treatment than with Na2SO4 treatment. Ni concentrations in the shoots were strongly increased by NaCl salinity, while concentrations of Br in the shoots and storage roots were significantly reduced by NaCl salinity. Rb concentrations in shoots and storage roots were significantly reduced by Na2SO4 salinity, but not by NaCl salinity. Concentration of Cs in the shoots was increased by both types of salinity, but Cs concentration of the roots was increased by Na2SO4. Concentration of Ba in the shoots was lowered by Na2SO4 treatment, while it was increased in the roots by Na2SO4 salinity. Salinity did not affect the Ce concentration in the shoots but increased it in the storage root, and NaCl salinity increased U concentration in the roots of the carrot plants. Copyright © 2008 John Wiley & Sons, Ltd.
X‐ray absorption spectroscopy at the NiK edge in Stackhousia tryonii Bailey hyperaccumulator
Authors: Ionescu M. , Bhatia N. P. , Cohen D. D. , Kachenko A. , Siegele R. , Marcus M. A. , Fakra S. , Foran G.
Published: September 2008

Young plants of Stackhousia tryonii Bailey were exposed to 34 mM Ni kg−1 in the form of NiSO4· 6H2O solution and grown under controlled glasshouse conditions for a period of 20 days. Fresh leaf, stem and root samples were analysed in vivo by micro x‐ray absorption spectroscopy (XAS) at the NiK edge. Both x‐ray absorption near edge structure and extended x‐ray absorption fine structure spectra were analysed, and the resulting spectra were compared with spectra obtained from nine biologically important Ni‐containing model compounds. The results revealed that the majority of leaf, stem and root Ni in the hyperaccumulator was chelated by citrate. Our results also suggest that in leaves Ni is complexed by phosphate and histidine, and in stems and roots, phytate and histidine. The XAS results provide an important physiological insight into transport, detoxification and storage of Ni in S. tryonii plants. Copyright © 2008 John Wiley & Sons, Ltd.
Zur Kristallchemie der Oxoosmate
Authors: Müller‐Buschbaum Hanskarl
Published: September 2008

Die Kristallchemie von Oxiden des Osmiums zeigt dieses in unterschiedlicher Wertigkeit und generell im anionischen Teil des Festkörpers. Die klare Entscheidung zugunsten des anionischen Teils der Kristallstrukturen wird durch die Kombination von Osmium mit großen Kationen wie Alkalimetalle, Erdalkalimetalle und Selten Erdmetalle bedingt. Trotz unterschiedlicher Valenzen des Osmiums ist seine Umgebung durch Sauerstoff weitgehend oktaedrisch. Neben isolierten OsO6‐Oktaedern, kantenverknüpften$^{1}_{\infty}\rm [Os_{2}O_{10}]$‐Oktaederdoppeln (die Os‐Os–Wechselwirkungen zeigen), $^{1}_{\infty}\rm [OsO_{5}]$‐Ketten und zwei sowie dreidimensionalen Netzwerken bilden Oxoosmate Perowskite, Pyrochlore und Stapelvarianten der Perowskite. K2OsO5 ist ein Beispiel für Osmium in ungewöhnlicher Sauerstoffkoordination. Am Ende werden zwei Osmium‐Metall‐Cluster vorgestellt.
Ternary Magnesium Compounds RE23Ni7Mg4 (RE = La, Ce, Pr, Nd, Sm) with Pr23Ir7Mg4 Type Structure
Authors: Tuncel Selcan , Hermes Wilfried , Chevalier Bernard , Rodewald Ute Ch. , Pöttgen Rainer
Published: September 2008

New rare earth‐rich compounds RE23Ni7Mg4 (RE = La, Ce, Pr, Nd, Sm) were synthesized from the elements in sealed tantalum tubes in a water‐cooled sample chamber of an induction furnace. The samples were characterized via X‐ray powder diffraction. The RE23Ni7Mg4 compounds crystallize with the hexagonal Pr23Ir7Mg4 type structure, space group P63mc. The structures of La23Ni7Mg4 (a = 1013.7(3), c = 2295.2(8) pm, wR2 = 0.0371, 2283 F2 values, 75 variables) and Pr23Ni7Mg4 (a = 992.8(3), c = 2243.0(5) pm, wR2 = 0.0634, 2462 F2 values, 74 variables) were refined from single crystal X‐ray diffractometer data. Striking structural motifs are nickel centered trigonal prisms formed by the rare earth elements and isolated Mg4 tetrahedra (319 pm as Mg–Mg distance in La23Ni7Mg4). The trigonal RE6Ni prisms exhibit short RE–Ni distances (287–306 pm in La23Ni7Mg4). The prisms are condensed via common edges, leading to a rigid three‐dimensional network in which the Mg4 tetrahedra are embedded. Temperature dependent magnetic susceptibility data of Ce23Ni7Mg4 indicate Curie‐Weiss behavior with an experimental magnetic moment of 2.54 μB/Ce atom, indicative for stable trivalent cerium. No magnetic ordering is evident down to 3 K.
A Missing Rare‐Earth Oxide Halide Structure Now Observed For Scandium Oxide Iodide, ScOI
Authors: Zimmermann Sina , Meyer Gerd
Published: September 2008

Single crystals of ScOI were obtained from the residue of a vacuum sublimation of crude ScI3. The colourless plates crystallize with a new structure type: Monoclinic, C2/m, Z = 8, a = 1933.3(6) pm, b = 386.10(8) pm, c = 722.4(2) pm, β = 93.51(3)°, Vm = 538.2(3) cm3 mol−1. The structure represents a missing link between the YOF/SmSI type variants (CN of the metal ion 4+3, only 36 nets stacked) and the PbFCl and FeOCl structure types (only 44 nets stacked, CN 4+4 and 4+2, respectively). In ScOI there are 44 (Sc, O) and 36 nets (I) stacked such that ScIII has a coordination number of 4+3.
Spectroscopic Study of YBa3B9O18, an Interesting Material Containing a Six‐membered Borate Ring
Authors: Baran Enrique J.
Published: September 2008

The infrared (IR) and Raman spectra of YBa3B9O18 were recorded and interpreted on the basis of the D3h local symmetry of the six membered planar B3O6 rings present in its structure. For comparative purposes also the IR spectra of NdBa3B9O18, GdBa3B9O18 and YbBa3B9O18 were recorded and analyzed.
Tetrakis(acetonitrile)‐dibromo‐nickel(II), [Ni(CH3CN)4Br2]
Authors: Getsis Anna , Mudring Anja‐Verena
Published: September 2008

[Tetrakis(acetonitrile)‐dibromo‐nickel(II)], [Ni(CH3CN)4Br2], was obtained from a solution of nickel(II) bromide in acetonitrile at 258 K. The crystal structure [orthorhombic, Pcab (no. 61), a = 884.0(2) pm, b = 1201.8(2) pm, c = 1323.6(3) pm, V = 1406.2(5)·106 pm3, Z = 4, R1/wR2 for 1247 reflections with I0>2σ(I0): 0.0384/0.0873] shows NiII coordinated in the form of an elongated octahedron by two trans coordinating bromide anions and four equatorial acetonitrile molecules. These [Ni(CH3CN)4Br2] molecular units are connected to each other by non‐classical hydrogen bonds forming a distorted cubic close packed arrangement.
The New Crystalline Mixed Valent Solids TlIn4Se5X (X: Cl, Br) and TlIn4S5Cl: Structure and Nanoscopic Defects Investigated by Combined Application of X‐ray and HRTEM Studies
Authors: Nickel V. , Reiner C. , Schlosser M. , Deiseroth H.‐J. , Kienle L. , Xhaxhiu K.
Published: September 2008

The title compounds TlIn4Se5X (X = Cl: P21/m, a = 9.275(2) Å, b = 4.102(1) Å, c = 15.376(3) Å, β = 92.77(2)°; X = Br: P21/m, a = 9.294(2) Å, b = 4.117(1) Å, c = 15.376(3) Å, β = 92.48(2)°) and TlIn4S5Cl (P21/m, a = 8.951(1) Å, b = 3.924(6) Å, c = 15.058(8) Å, β = 93.75(2)°) belong to a group of indium based mixed valent solids with In+ replaced by Tl+ according to a formulation Tl+ (In2)4+ 2In3+ 5Ch2− X−. The ternary members of this group of solids crystallize either in the monoclinic In5Ch5Cl or in the orthorhombic In5Ch5Br type („Cl‐type, Br‐type”︁). All quaternary title compounds, surprisingly including the bromide TlIn4Se5Br, crystallize in the Cl‐type. In both structure types the M+ coordination is topologically identical with the coordination of the (In2)4+ groups. This special structural aspect is the most important basis for an understanding of the differences between the two closely related structure types and their defect structures. A variety of nanoscaled defects (lamellar twinning, polymorphic and phasoid intergrowth) together with a pronounced needle shaped morphology („nanowires”︁) is observed for all crystals of this group of compounds. As a consequence X‐ray single crystal structure refinements are of limited precision (R‐ values) but are completed by HRTEM investigations in order to compensate this drawback. The combination of both methods offers deep insight into details of the differences between ideal structures and real structures.
Copper(I) Carboxylates of Type [(nBu3P)mCuO2CR] (m = 1, 2, 3) – Synthesis, Properties, and their Use as CVD Precursors
Authors: Jakob Alexander , Shen Yingzhong , Wächtler Thomas , Schulz Stefan E. , Gessner Thomas , Riedel Ralf , Fasel Claudia , Lang Heinrich
Published: September 2008

Copper(I) carboxylates of type [(nBu3P)mCuO2CR] (m = 1: 3a, R = Me; 3b, R = CF3; 3c, R = Ph; 3d, R = CH=CHPh. m = 2: 4a, R = Me; 4b, R = CF3; 4c, R = Ph; 4d, R = CH=CHPh. m = 3: 8a, R = Me; 8b, R = CF3; 8c, R = CH2Ph; 8d, R = (CH2OCH2)3H; 8e, R = cC4H7O) are accessible by following synthesis methodologies: the reaction of [CuO2CR] (1a, R = Me; 1b, R = CF3; 1c, R = Ph; 1d, R = CH=CHPh) with m equivalents of nBu3P (2) (m = 1, 2, 3), or treatment of [(nBu3P)mCuCl] (5a, m = 1; 5b, m = 2) with [KO2CCF3] (6). A more straightforward synthesis method for 8a – 8e is the electrolysis of copper in presence of HO2CR (7a, R = Me; 7b, R = CF3; 7c, R = CH2Ph; 7d, R = (CH2OCH2)3H; 7e, R = cC4H7O) and 2, respectively. This method allows to prepare the appropriate copper(I) carboxylate complexes in virtually quantitative yield, analytically pure form, and on an industrial scale.

IR spectroscopic studies reveal that the carboxylic units in 4, 5, and 8 bind in a unidentate, chelating or μ‐bridging fashion to copper(I) depending on m and R.

The thermal properties of 4, 6, and 8 were determined by TG and DSC studies. Based on TG‐MS experiments a conceivable mechanism for the thermally induced decomposition of these species is presented.

Hot‐wall Chemical Vapor Deposition experiments (CVD) with precursor 4b showed that copper could be deposited at 480 °C onto a TiN‐coated oxidized silicon substrate. The copper films were characterized by SEM and EDX studies. Pure layers were obtained with copper particles of size 200 – 780 nm.
Lumineszente Eisen‐Platin‐Mehrkernkomplexe mit funktionalisierten Acetyliden
Authors: Meier Mirko , Görls Helmar , Walther Dirk
Published: September 2008

Luminescent Iron‐Platinum Multinuclear Complexes with Functionalyzed Acetylides

The reaction of [(dippf)2PtCl2] with 2,5 eq. of 5′‐diethinyl‐2,2′‐bipyrimidine in THF/diethylamine results in both the formation of [(dippf)2Pt(‐C≡C‐C8H4N4‐C≡CH)2] (1) and [μ‐(C≡C‐C8H4N4‐C≡C){(dippf)2Pt(‐C≡C‐C8H4N4‐C≡CH)}2] (2) as minor product (dippf: 1,1′‐diisopropylphosphino‐ferrocene; C8H4N8: bipyrimidinediyl‐).

The solid state structures of the complexes were determined by X‐ray crystallography. 1 and 2 are luminescent at room temperature. Quenchung of the emission was observed upon reaction of 1 with PdCl2 or μ‐dichloro‐tetraethylen‐dirhodium.
Pr10(C2)2Br16: Eine neue Struktur mit diskreten Pr10‐Doppeloktaedern
Authors: Schaloske Manuel Christian , Mattausch Hansjürgen , Kienle Lorenz , Simon Arndt
Published: September 2008

Pr10(C2)2Br16: A New Structure with Discrete Octahedra Doubles

The compound Pr10(C2)2Br16 is prepared from Pr, PrBr3, and C with a molar ratio of 7:8:6 at 780 to 820 °C as the major phase, forming polygonal black crystals with a metallic lustre which are moisture and air sensitive. It crystallizes in the triclinic system, $P{\bar 1}$, with lattice parameters a = 9.096(2) Å, b = 12.185(2) Å, c = 16.688(3) Å, α = 79.57(3)°, β = 89.86(3)°, γ = 84.38(3)°. In the crystal structure the Pr atoms form Pr6 octahedra centered by C2 groups, and two such octahedra are condensed via edges to form Pr10 units. The bromine atoms coordinate the doubleoctahedra above all free edges and connect them via $Br^{i-i}_{\rm 4/2} Br^{i-a}_{\rm 8/2} Br^{a-i}_{\rm 8/2}$ bridges. The mean C‐C distance in the C2 unit is 1.42(2) Å. HRTEM micrographs display the characteristic fragment of the Pr10 double octahedron. Furthermore antiphase domains are identified as specific defects in the structure.
The Structure of Virus Capsids
Authors: Andersson Sten
Published: September 2008

With the new periodic exponential mathematics, with new structure building principles (morphotropic, bilateral and disk), with the plural concept and the volume variations, we have a good understanding of the evolution of the structure of viruses. A massive demonstration of this is the simple Blue Tongue series. The structures of nine viruses from the smallest to the very big capsids are described as closely related: Parvovius (m=1), Coxsackie (m=2), Semliki (m=3), Simian (m=4), Cowpea mosaic (m=5), Blue Tongue (m=6), Herpes (m=7), Vacant (m=8), Human Adenovirus Type 5 (m=9), Archaeal (m=10).
CaAg – SrAg – BaAg: Zwischen CrB‐ und FeB‐Strukturtyp
Authors: Harms Wiebke , Burggraf Fabian , Daub Michael , Dürr Ines , Röhr Caroline
Published: September 2008

CaAg – SrAg – BaAg: Between CrB and FeB Structure Type

Depending on both electronic (valence electron numbers) and geometric (atom size ratios) characteristics of the contributing elements, the 1:1 compounds AIIM of the heavier alkaline earth elements A and electron‐rich transition metals M form the well known CrB or FeB structure types. Both structure types exhibit M zig‐zag chains, which are stacked in different orientations against each other. In systematic studies of the pseudo‐binary sections CaxSr1−xAg and SrxBa1−xAg three new ternary phases with different stacking variants between the CrB (cubic stacking, c) and the FeB (hexagonal stacking, h2) structure type have been prepared and determined on the basis of single crystal x‐ray data. Starting from CaAg (CrB type, stacking c), up to 25 percent of Sr (i.e. in Ca0.75(2)Sr0.25(2)Ag: orthorhombic, space group Cmcm, a = 413.4(1), b = 1157.8(3), c = 467.4(2) pm, Z = 4, R1 = 0.0453) can be substituted without a change in the structure type. At a 1:1 ratio of Ca and Sr, a new structure type with stacking sequence (hc5)2 is formed (Ca0.48(3)Sr0.52(3)Ag: space group Pnma, a = 4800.1(1), b = 471.8(12), c = 624.11(9) pm, Z = 24, R1 = 0.0881). Further reduced cubic stacking ((hc2)2) is observed in the Sr rich region with Ca proportions between 39 and 25(2) % (space group Pnma, x = 0.39(1)/0.25(2): a = 2412.2(3)/2434.67(4), b = 472.75(5)/473.97(8), c = 626.17(7)/629.2(3) pm, Z = 12, R1 = 0.0430/0.0489) where the HT‐TbNi structure type is formed. The stability range of the SrAg structure type ((hc)2) starts at a Ca content of 5 % (Ca0.05Sr0.95Ag: space group Pnma, a = 1643.1(2), b = 476.79(7), c = 636.27(9) pm, Z = 8, R1 = 0.0318). From a new second modification of SrAg (space group Pnma, a = 4131.5(4), b = 478.79(6), c = 638.81(6) pm, Z = 20, R1 = 0.0394) up to a Ba proportion of 8 percent, the α‐CaCu structure type with sequence (hch2c)2 is formed. The stability range of the FeB structure with purely hexagonal stacking extends from Sr0.84(1)Ba0.16(1)Ag (a = 830.78(12), b = 479.35(8), c = 644.93(11) pm, Z = 4, R1 = 0.0413) to the border phase BaAg. In an accompanying computational study, the chemical bonding in the binary compounds CaAg, SrAg and BaAg is analyzed using FP‐LAPW band structure methods. Together with geometrical criteria, the results are used to compare and discuss the stability of the different stacking variants of the polar intermetallic 1:1 phases inbetween the CrB and the FeB structure type.
Die molekularen Cluster [Bi10Au2](EBi3X9)2 (E = As, Bi; X = Cl, Br) – Synthese, Kristallstrukturen, Drillingsbildung und chemische Bindung
Authors: Wahl Bernhard , Ruck Michael
Published: September 2008

The Molecular Clusters [Bi10Au2](EBi3X9)2 (E = As, Bi; X = Cl, Br) – Synthesis, Crystal Structures, Twinning and Chemical Bonding

Cooling stochiometric mixtures of molten Bi, BiX3, (X = Cl, Br), E (E = As, Bi), and Au yields black crystals of the low‐valent, molecular compounds [Bi10Au2](EBi3X9)2. The molecules consist of an icosahedral [Bi10Au2]6+ cluster enclosed by two (EBi3X9)3− hemi‐spheres connected via Au–E bonds. The discrepancy of the symmetries of the heteroicosahedron (D5d) and the caps (C3v) gives rise to pseudomerohedral twinning. As a consequence of the superposition of three monoclinic unit cells (space group P21/c; e.g. a = 1059.02(5) pm, b = 1528.60(5) pm, c = 1463.55(6) pm, β = 93.69(1)° for E = Bi, X = Br), the diffraction patterns of the crystals simulate trigonal R‐centered cells with lattice parameters of a ≈ 3000 pm and c ≈ 1700 pm. The constitution of the molecules can be rationalized in terms of an uncommon combination of known and new structural motives: The Wade cluster [Bi10]4+ is capped by two Au+ atoms forming the hetero‐icosahedron [Bi10Au2]6+. In the anionic caps (E0BiII3X9)3−, the BiII atoms are in square planar coordination of four halogenide anions and are furthermore bonded to the E atom on the central axis of the molecule. Since the interaction between E and Au can be classified as a donor‐acceptor bond, the [AuI(E0R3)]2− fragment with R = BiIIX2/1X2/2 is a complex analog to cations [AuI(E0R3)]+ with E = P, As, Sb and R = alkyl or aryl.
Co2As2O5 – the First Cobalt(II)‐Arsenate(III)
Authors: Lösel Stefan , Hillebrecht Harald
Published: September 2008

Co2As2O5 was obtained as a by‐product from the single crystal growth of CoAs2. The triclinic crystal structure ($P{\bar 1}$, a = 6.223(1), b = 9.169(2), c = 9.259(2) Å, α = 66.95(3), β = 82.18(3), γ = 79.28(3)°, Z = 4, R1(F) = 0.057, wR2(F2) = 0.141) represents a new structure type. As typical for AsIII it contains trigonal‐pyramidal ψ‐tetrahedra [AsO3]3−. The four crystallographically different As‐atoms are arranged in monomeric units and trimeric chain fragments [As3O7]5−. The surroundings of the four cobalt(II) atoms are remarkably unequal and show tetrahedral, trigonal‐bipyramidal and distorted octahedral coordinations. The octahedra form double‐chains linked to layers by the trigonal bipyramids and dimers of the tetrahedra.
Synthesis and Characterization of the First Salts of the ortho‐Selenidoindate Anion [InSe4]5−
Authors: Heine Johanna , Dehnen Stefanie
Published: September 2008

Single‐crystalline potassium salts of the so far unknown ortho‐selenidoindate anion [InSe4]5−, K12[InSe4]2Se (1), K9[InSe4][Se2]Se (2), and a novel hydrate of the decaselenidotetraindate anion [In4Se10]8−, [K8(H2O)11][In4Se10] (3), were prepared and structurally characterized by means of X‐ray diffractometry. The investigations complete the series of known ortho‐chalcogenidoindate anions and show further peculiarities of the indate chemistry with respect to the properties of related stannates.
SrNi2Ge and SrNi3Ge2 – Two Related Hexagonal Germanides
Authors: Hlukhyy Viktor , Fässler Thomas F.
Published: September 2008

The strontium nickel germanides SrNi2Ge and SrNi3Ge2 were prepared by melting mixtures of the elements in an arc‐furnace under an argon atmosphere. Single crystals were obtained by special heat treatment in welded tantalum ampoules. The compounds were investigated by X‐ray diffractions both on powders and single crystals. SrNi2Ge crystallizes with the hexagonal GdPt2Sn structure with space group P63/mmc, a = 4.128(1), c = 10.479(6) Å, wR2 = 0.105, 92 F2 values, 9 variable parameters. In this structure the nickel and germanium atoms build two‐dimensional [Ni2Ge] layers, which are separated by the Sr atoms. The crystal structure of SrNi3Ge2 can be described as a substitution variant of the YPtAs structure with space group P63/mmc, a = 4.0511(1), c = 14.2187(6) Å, wR2 = 0.075, 117 F2 values, 12 variable parameters. Two adjacent [NiGe] layers in this structure are interconnected by Ni atoms, forming [Ni3Ge2] blocks, which are separated by Sr atoms. The structure of SrNi2Ge and SrNi3Ge2 both are related to the AlB2‐type structure. The crystal chemistry and chemical bonding in these structures is discussed in terms of group‐subgroup relation, LMTO band structure calculation, and analysis using the Electron Localization Function (ELF).
Solvothermal Syntheses, Crystal Structures and Selected Optical Properties of [M(C8N5H23)]2Sn2S6 (M = Co, Fe, Ni; C8N5H23 = tetraethylenepentamine)
Authors: Pienack Nicole , Lehmann Stefanie , Lühmann Henning , El‐Madani Marzog , Näther Christian , Bensch Wolfgang
Published: September 2008

Three new thiostannates [Co(C8N5H23)]2Sn2S6 (I), [Fe(C8N5H23)]2Sn2S6 (II) and [Ni(C8N5H23)]2Sn2S6 (III) were synthesized under solvothermal conditions. In all compounds the [Sn2S6]4− anion acts as a bidentate or μ2 ligand bridging two symmetry related [M(C8N5H23)]2+ cations. Despite the identical building units only compounds I and II are isostructural crystallizing in the tetragonal space group I41/a, whereas compound III crystallizes in space group P21/n. A detailed analysis of the intermolecular interactions reveals remarkable differences between I/II and III which may be responsible for the crystallization in different symmetries and space groups. The slightly different bonding situations in the [Sn2S6]4− anion in I/II and III are reflected in the Raman spectra. For all three compounds the UV/Vis spectra show d‐d transitions energetically below the absorption edge.
Dimerization of the 2‐(Methylselenomethyl)benzimidazole‐silver(I) Cation Involving a AgI–AgI Interaction
Authors: Leboschka Markus , Sieger Monika , Niemeyer Mark , Záliš Stanislav , Kaim Wolfgang
Published: September 2008

Reacting the bidentate ligand 2‐(methylselenomethyl)‐1H‐benzimidazole (msb) with AgBF4 in CH3CN did not produce the expected [Ag(msb)2]+ ion with two five‐membered chelate rings but the dimeric [Ag2(msb)2]2+, isolated and crystallized from acetonitrile/methanol as {[Ag(msb)(CH3CN)]2}(BF4)2 with six‐membered chelate rings Ag‐Ag‐Se‐C‐C‐N involving a Ag‐Ag bond of 3.156(1) Å distance. DFT calculations reproduce the observed molecular structure of the dication.
Model Studies on the Formation and Reactions of Solid Glycine Complexes at the Coasts of a Primordial Salty Ocean
Authors: Yusenko Kirill , Fox Stefan , Guni Petra , Strasdeit Henry
Published: September 2008

Laboratory experiments pertinent to the prebiotic hot‐volcanic‐coast scenario are described. When artificial primordial seawater which contained NaCl, KCl, MgCl2, CaCl2, and a small amount of glycine (Hgly) was evaporated to dryness, it was found that in the remaining solid salt mixture the amino acid was exclusively present as CaCl2(Hgly)·H2O (1). The coordination compound 1 was also obtained by controlled efflorescence of the corresponding trihydrate CaCl2(Hgly)·3H2O (2). A characteristic structural feature of crystalline 2 is [CaCl(Hgly)(H2O)3]+ units that are interconnected to form one‐dimensional coordination polymers. On thermolysis at 350 °C in a nitrogen atmosphere, compound 1 yielded, inter alia, 15 different methylated and ethylated pyrroles. In contrast, the artificial sea salt–glycine mixtures, despite containing 1, produced no detectable amounts of organics under the same conditions. Hydrochloric acid from thermal hydrolysis of the sea salt component MgCl2·6H2O may be responsible for this different behavior. 1, 2, and the related compounds CaCl2(Hgly)2·4H2O (3), and MgCl2(Hgly)2·2H2O (4) have been prepared in analytically pure form on a multi‐gram scale. Methods used in this study were single‐crystal and powder X‐ray diffraction, infrared and Raman spectroscopy, thermogravimetric and differential thermal analysis, and gas chromatography–mass spectrometry.
Dinuclear Complexes with Dithiolate‐bridged Square‐pyramidal and Octahedral Nickel(II) Ions – Syntheses, Characterization, and Crystal Structures
Authors: Lozan Vasile , Syre Ronny , Kersting Berthold
Published: September 2008

The ability of the dinuclear nickel(II) complex [NiII2L(L′)]+, where L2− represents a macrocyclic N6S2 ligand, to coordinate monodentate coligands has been examined. Three complexes with L′ = CH3CN, CH2=CHCN, and (BH3CN)− have been synthesized: [NiII2(L)(NCMe)][BPh4]2 (3), [NiII2(L)(NCCH=CH2)][BPh4]2 (4), and [NiII2(L)(NCBH3)][ClO4] (5). All complexes were characterized by elemental analysis, IR and UV/Vis spectroscopy, and X‐ray crystallography. The complexes were found to be isostructural. Each coligand is bonded in a monodentate fashion to generate a central N3Ni(SR)2NiN4 core structure, with the dithiolate‐bridged NiII ions in square‐pyramidal N3S2 and distorted‐octahedral N4S2 coordination environments, respectively. The charged (BH3CN)− group interacts more strongly with the [Ni2L]2+ fragment than the neutral nitrile ligands as reflected by the Ni–N(nitrile) distances which are significantly longer in 3 and 4 than in 5. An analysis of the temperature‐dependent magnetic susceptibility data for 3 reveals the presence of weak ferromagnetic exchange interactions between the NiII ions with a value for the magnetic exchange coupling constant J of 39 cm−1 (H = −2JS1S2).
Bi‐ and Trinuclear Copper(II) Complexes with a Bridging Pyrazole/Oxime Ligand: Structures and Magnetic Properties
Authors: Penkova Larysa , Demeshko Serhiy , Haukka Matti , Pavlenko Vadim A. , Meyer Franc , Fritsky Igor O.
Published: September 2008

The pyrazole‐based asymmetric ligand 3‐[(1E)‐N‐hydroxyethanimidoyl]‐4‐methyl‐1H‐pyrazole‐5‐carboxylic acid (L) is shown to serve as a versatile ligand in copper(II) coordination chemistry with both the pyrazole and the oxime groups as potential bridges upon deprotonation. Three complexes [Cu2(L–2H)2(DMSO)(H2O)]·H2O (1a), [Cu2(L–2H)2(DMSO)2]·H2O (1b) and [Cu3(L–3H)2(Py)5] (2) have been isolated and their crystal structures determined by X‐ray single crystal analysis. The former feature a bis(pyrazolato)‐bridged dicopper core, whereas adjacent copper ions are spanned by a pyrazolate and an oximate in the latter complex. The presence of different species in solution depending on the pH has been demonstrated by EPR. Alterations in the protonation state are accompanied by changes in nuclearity, which cause pronounced changes in color, magnetic and EPR properties. Magnetic susceptibility measurements in the temperature range 1.8 – 300 K have revealed antiferromagnetic exchange coupling between copper(II) ions both in the bi‐ and trinuclear complexes (J = –160 cm−1 for l and –191 cm−1 for 2). The binuclear species [Cu2(L–2H)2] is almost silent in X‐band EPR at 77 K due to antiparallel alignment of the unpaired CuII electrons, while the EPR signatures of species at alkaline condition suggest a Cu‐centered S = 1/2 state.
Low‐Temperature NMR and Crystal Structure Analyses of a Hemilabile Tin Complex
Authors: Objartel Ina , Ott Holger , Stalke Dietmar
Published: September 2008

The reaction of SnCl2 with the Janus Head ligands Ph2PPic (1, Pic = 2‐picolyl) and Ph2P(NSiMe3)Pic (2) led to the novel tin complexes [(Ph2PPic)Sn(Cl)][SnCl3] (4) and [(Cl)2Sn{(NH)(Pic)PPh2}]·THF (6). The hemilability of the Ph2PPic (1) ligand in 4 was investigated by low temperature 119Sn and 31P NMR studies. A remarkable equilibrium of two formal SnCl2 units with 1 could be revealed. Crystal structure analysis of 4 and 6 substantiated the understanding of the hemilabile behaviour of the presented Janus Head ligands.
Sterically Demanding Aminophosphines: Palladium and Gold Complexes of 1,2‐Bis(dimesitylphosphanylamino)benzene
Authors: Majoumo‐Mbe Felicite , Lönnecke Peter , Hey‐Hawkins Evamarie
Published: September 2008

1,2‐Bis(dimesitylphosphanylamino)benzene reacts with [PdCl2(NCMe)2] (1:1) or [AuCl(THT)] (THT = tetrahydrothiophene; 1:2 or 1:1) in dichloromethane to give dimeric, dinuclear complex trans‐[PdCl2(1,2‐{PMes2(NH)}2C6H4‐κ2P,P′)]2 (1), dinuclear complex [(AuCl)2(1,2‐{PMes2(NH)}2C6H4‐κ2P,P′)] (2) and trinuclear cationic complex [Au{1‐PMes2(NH)‐2‐AuCl(PMes2NH)C6H4‐κ2P,P′}2]Cl (3). Compounds 1‐3 were characterized by NMR spectroscopy, IR spectroscopy and X‐ray crystallography.
Tetramethoxy‐λ4‐tellane and Tetrakis(2,2,2‐trifluoroethoxy)‐λ4‐tellane
Authors: Betz Richard , Stapel Martin , Pfister Maximilian , Roeßner Felix W. , Reichvilser Moritz M. , Klüfers Peter
Published: September 2008

Two tetraalkoxy‐λ4‐telluranes were prepared from tellurium tetrachloride and the sodium salts of methanol and 2,2,2‐trifluoroethanol, respectively. Their molecular structures which were determined by single‐crystal X‐ray diffraction show dipolar intermolecular contacts. NBO analyses for the title compounds were conducted to assess the role of the stereochemically active lone pair on the tellurium atoms.
Measurement of some rheological properties of plastic fats with an extrusion modification of the shear press
Authors: Vasic Ilija , deMan John M.
Published: September 2008

An extrusion attachment for the Lee‐Kramer shear press is described. With this instrument some rheological properties of lard, margarine and shortening were measured. These included extrusion pressure and specific work of extrusion. By variation of extrusion speed and size of orifice a variety of rates of deformation could be obtained. When the rate of deformation was plotted against the specific work of extrusion, curves were obtained which were nearly straight beyond deformation rates of about 1 sec‐1. The tangent to these curves represents the apparent viscosity. By measurement of the hardness before and after extrusion the work softening resulting from the extrusion could be measured. Some possible uses of the technique are discussed.
Potentiometric titration of sulfate in some typical anionic sulfonate and sulfate surfactants
Authors: Crabb Norman T. , Persinger Harry E.
Published: September 2008

The inorganic sulfate content of several typical anionic surface active agents has been determined by a potentiometric titration with lead nitrate using the potassium ferri‐ferro cyanide couple to detect the end point. The recovery of added sodium sulfate varied from ‐6 to +5% of the contained amount at the 0.5% sulfate level.