bluuebunny/crossref_metadata_2025_split huggingface dataset:
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

AbstractFrequently, 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

AbstractShrinkage 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

AbstractAvian 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

AbstractThis 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

AbstractThe 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

AbstractThis 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

AbstractThe 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

AbstractThis 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

AbstractYoung 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

AbstractDie 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

AbstractNew 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

AbstractSingle 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

AbstractThe 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

Abstract[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

AbstractThe 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

AbstractCopper(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

AbstractLuminescent Iron‐Platinum Multinuclear Complexes with Functionalyzed AcetylidesThe 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.