bluuebunny/crossref_metadata_2025_split huggingface dataset:
Preparation of magnetic polystyrene latex via the miniemulsion polymerization technique
Authors: Csetneki I. , Faix M. Kabai , Szilágyi A. , Kovács A. L. , Németh Z. , Zrinyi M. 
Published: August 2004

AbstractMagnetic iron oxide (magnetite, Fe3O4) nanoparticles were encapsulated with polystyrene to give a stable water‐based magnetic polymer latex, using the miniemulsion polymerization technique. The resulting magnetic latexes were characterized with transmission electron microscopy (TEM), dynamic light scattering (DLS), vibrating sample magnetometer measurements (VSM), and 57Fe Mössbauer spectroscopy measurements. TEM revealed that all magnetite nanoparticles were embedded in the polymer spheres, leaving no empty polystyrene particles. The distribution of magnetite particles within the polystyrene spheres was inhomogeneous, showing an uneven polar appearance. The DLS measurements indicated a bimodal size distribution for the particles in the latexes. According to our magnetometry and Mössbauer spectroscopy data, the encapsulated magnetite particles conserve their superparamagnetic feature when they are separated in the polymer matrix. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4802–4808, 2004
Synthesis and characterization of oxidized cellulose
Authors: Zimnitsky Dmitry S. , Yurkshtovich Tatiana L. , Bychkovsky Pavel M. 
Published: August 2004

AbstractSamples of oxidized cellulose (OC) with various carboxyl contents and degrees of crystallinity were obtained by the oxidation of native and mercerized cellulose with a solution of nitrogen(IV) oxide in CCl4. A detailed characterization of these OC samples was performed. The effect of oxidation conditions (concentration of N2O4 in the solution and oxidation time) and starting cellulose material on OC characteristics (carboxyl, carbonyl and nitrogen content, degree of crystallinity and polymerization, surface area and swelling, and acidic properties) was investigated. Reactivity in the oxidation process was higher in mercerized cellulose than in native cellulose. The action of dilute solutions (10–15%) of N2O4 did not affect the degree of crystallinity of cellulose samples. Under these conditions, the oxidation took place mainly in amorphous regions and on the surface of crystallites. Oxidation in a concentrated (40%) N2O4 solution led to the destruction of crystallites, which increased the surface area and swelling of cellulose in water. The surface area and the swelling of OC samples increased with a decrease in the index of crystallinity. The acidic properties of OC were shown to increase with an increase of swelling in water. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4785–4791, 2004
Highly soluble conducting poly(ethylene oxide) grafted at two sites of poly(o‐aminobenzyl alcohol)
Authors: Hua Fengjun , Ruckenstein Eli 
Published: August 2004

AbstractPoly(o‐aminobenzyl alcohol) (POABA) was grafted with poly(ethylene oxide)s (PEOs) through the reaction of tosylated PEO with both the hydroxide and amine moieties of reduced POABA. Reduced POABA was prepared through the acid‐mediated polymerization of o‐aminobenzyl alcohol, followed by neutralization with an aqueous ammonium hydroxide solution and reduction with hydrazine. The grafted copolymers were very soluble in common polar solvents, such as chloroform, tetrahydrofuran, and dimethylformamide, and the copolymers with longer PEO side chains (number‐average molecular weight > 164) were even water‐soluble. The conductivities of the doped grafted copolymers decreased with increasing PEO side‐chain length because of the nonconducting PEO and its torsional effect on the POABA backbone. The conductivity of highly water‐soluble POABA‐g‐PEO‐350 was 0.689 × 10−3 S/cm, that is, in the semiconducting range. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4756–4764, 2004
Fundamental kinetic aspects of living radical polymerization and the use of gel permeation chromatography to shed light on them
Authors: Fukuda Takeshi 
Published: August 2004

AbstractThe control achievable by living radical polymerization (LRP) is based on a kinetic balance of the activation–deactivation reversible reactions, which are specific to LRP, with conventional elementary reactions such as initiation, propagation, and termination. This work describes, as plainly as possible, how chains grow and how their polydispersity evolves as they experience activation–deactivation cycles and how these processes can be quantitatively analyzed by gel permeation chromatography. A comprehensive probability theory on the polydispersity indices of LRP polymers is presented. © 2004 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 42: 4743–4755, 2004
Polyelectrolyte adsorption and multilayering on charged colloidal particles
Authors: Messina René , Holm Christian , Kremer Kurt 
Published: August 2004

AbstractIn this article we review the complexation behavior of charged polymers adsorbed onto charged substrates. In the first part we summarize the results obtained on the adsorption properties of a single polyelectrolyte chain with one or several oppositely charged spherical colloids. The results of various simulational studies are compared with theoretical predictions. After that, we show that under strong electrostatic coupling conditions one can also obtain complexations, where chain and colloid carry the same charge (like‐charge complexation). This effect is due to counterion correlation effects. Finally, we investigate the case of polyelectrolyte multilayers structures, which are composed of alternating polycations and polyanions on various substrate geometries. This structure, normally obtained by a so‐called layer‐by‐lay deposition, is very stable experimentally, but only poorly understood in terms of theoretical approaches. Our simulation results suggest that short range attractive interactions (e.g., van der Waals) are important for obtaining a stable sequence of multilayers. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3557–3570, 2004
Polyelectrolyte‐mediated bridging interactions
Authors: Podgornik Rudi 
Published: August 2004

AbstractPolyelectrolyte chains confined by macroions bearing electrostatic charges of opposite sign can mediate an effective attraction between the macroions. This polyelectrolyte‐mediated attraction is usually referred to as the bridging interaction. I review the theories of polyelectrolyte‐mediated interactions based on analytic mean‐field and variational approaches. I will describe the origin and the salient properties of this interaction in the context of planar and point macroions with special emphasis on the connection between the polymer chain conformations and the ensuing polymer mediated interactions. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3539–3556, 2004
Comment on the dynamic bead size and Kuhn segment length in polymers: Example of polystyrene
Authors: Ding Y. , Sokolov A. P. 
Published: August 2004

AbstractDiscrepancies between the length of a traditionally defined Kuhn segment length (lk) and a bead size estimated from experimental data have been reported in a number of articles. In this work we emphasize that the traditional definition of the Kuhn segment is an oversimplification and the characteristic ratio, C∞, is not the only parameter that defines a bead size. We show that the dynamic bead size in polystyrene (PS) might be as large as ∼50 monomers, whereas the traditionally defined Kuhn segment is ∼8–10 monomers. It is shown that with 50 monomers (M ∼ 5000) as a size of the dynamic bead, one can explain many inconsistencies in the interpretation of compliance and mechanical relaxation data known for low‐molecular weight PS. © 2004 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 42: 3505–3511, 2004
Mössbauer effect studies of disordered Fe–Ru alloys
Authors: Pöttker W. E. , Paduani C. , Ardisson J. D. , Ioshida M. I. 
Published: August 2004

AbstractThe bcc and hcp phases of disordered Fe100–xRux alloys are investigated with several experimental techniques to study the composition dependence of the magnetic properties in these structures. With an appropriate annealing the prepared samples are single phase. The iron rich alloys are ferromagnetic at room temperature with the bcc structure. However, an antiferromagnetic coupling is introduced with the addition of ruthenium. Above 30 at% Ru a paramagnetic behavior is observed at 300 K and 77 K, where the alloys have the hcp structure. In the ferromagnetic phase the Curie temperature decreases steadly with the increase of the ruthenium concentration. In the paramagnetic hcp phase the mean volume per atom is al‐most triplicated as compared to the bcc phase, which brings out the breakdown of the magnetization and the collapse of the hyperfine field at the iron sites simultaneously with the crystallographic phase transition. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Structural study of ferroelectric and paraelectric phases in PbK2LiNb5O15
Authors: Gagou Y. , Muller Ch. , Frémy M.‐A. , Mezzane D. , Elkaïm E. , Saint‐Grégoire P. 
Published: August 2004

AbstractThe structures of PbK2LiNb5O15 showing the ferroelectricity below about 640 K have been studied in the paraelectric and ferroelectric phases by means of synchrotron X‐ray powder diffraction. The data are analyzed with a Rietveld refinement method. It is found that the paraelectric structure and the ferroelectric one are of tetragonal and orthorhombic symmetry with P4/mbm and Pba2, respectively. The Pba2 structure gives a polar displacement along c‐axis, whose direction is consistent with that deduced from dielectric measurements. The refined chemical occupancies of the cations Pb, K and Nb give the site‐situation of these ions in the tunnels with square sections and pentagonal sections in each phase. (© 2004 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Orbital ordering and orbital fluctuations in transition metal oxides [phys. stat. sol. (b) 236, No. 2, 281–288 (2003)]
Authors: Oleś Andrzej M. 
Published: August 2004

AbstractThe labeling of Fig. 1(b) has to be corrected.See original phys. stat. sol. (b) 236, No. 2, 281–288 (2003)
Structural study of ferroelectric and paraelectric phases in PbK2LiNb5O15
Authors: Gagou Y. , Muller Ch. , Frémy M.‐A. , Mezzane D. , Elkaïm E. , Saint‐Grégoire P. 
Published: August 2004

AbstractThe cover picture of the present issue of physica status solidi (b) is a Fourier map calculated from the Pba2 space group, which corresponds to the ferroelectric structure of PbK2LiNb5O15. It was revealed by synchrotron X‐ray powder diffraction investigations reported in the paper [1]. Positions of the various Pb, K, and O atoms in the unit cell are indicated by the labels.
Pathology raw data in nonclinical laboratory studies for the pharmaceutical industry: The pathologists' view
Authors: Geoly Frank J. , Kerlin Roy L. 
Published: August 2004

AbstractPost‐mortem pathology data from nonclinical laboratory studies contain critical information for characterizing a new drug's safety and are pivotal for gaining an appreciation of potential hazards to humans. An understanding of the historical regulatory and scientific perspective on the nature of pathology data is valuable for assuring appropriate and useful audits of pathology material within nonclinical studies. This discussion reviews the specialty of pathology, the process of medical diagnosis, the definitions of ‘raw data’ as they pertain to histopathology data, and the rationale behind the consensus decisions made by industry and the Food and Drug Administration (FDA) in interpreting good laboratory practice (GLP) regulations for this type of data. Copyright © 2004 John Wiley & Sons, Ltd.
Ethical considerations in clinical trials
Authors: Whalen Matthew , Khin‐Maung‐Gyi Felix , Wambolt Ann L. 
Published: August 2004

AbstractEthics is no longer the privileged domain of a few academicians, nor of Institutional Review Boards/Ethics Review Committees (IRBs/ERCs) overseeing clinical trials. Ethical considerations impacting multiple aspects of the conduct of research are central to clinical research. As a result, there are ethical dimensions to every aspect of clinical research. This article results from a session at the 2003 Society of Quality Assurance (SQA) Annual Meeting in Washington, DC, USA. This summary of the ethical and public policy‐related underpinnings for our comments during the session should benefit those who were unable to attend the session as well as to provide further perspectives for those who participated in the discussion. Copyright © 2004 John Wiley & Sons, Ltd.
Science and Quality Assurance: From dose to overdose
Authors: Jones Anthony B. 
Published: August 2004

AbstractFor Quality Assurance to be a proactive partner in drug development we need to understand the scientific concepts that define and shape the pharmaceutical process. Drug development can be more easily understood by considering the basic scientific principles governing the numerous scientific disciplines that contribute to producing safe and effective drugs. This article describes how two of these principles influence drug development from choice of molecule through to clinical testing and how they interact with FDA regulations and Quality Assurance. Copyright © 2004 John Wiley & Sons, Ltd.
What's new?
Authors: Broughton Harold Steven , Hattemer‐Apostel Rita 
Published: August 2004

AbstractThe What's New? section in the Quality Assurance Journal aims to draw attention to items of importance to QA professionals. There is usually a three‐month interval between final submission of manuscripts and distribution of the journal. For this issue, the entries in the What's New? section arise from the period of 1 March 2004 to 31 May 2004. If you feel that there is any other new information that should be brought to the attention of readers, please let us know by e‐mailing rha@verdandi.ch. Copyright © 2004 John Wiley & Sons, Ltd.
Why has feedback systems thinking struggled to influence strategy and policy formulation? Suggestive evidence, explanations and solutions
Authors: Warren Kim 
Published: August 2004

AbstractProponents of system dynamics expound its benefits for understanding and managing complex social systems. However, usage of system dynamics remains low, which questions the true value that policy‐makers gain from the approach as currently delivered. Feedback systems thinking and causal loop diagrams currently dominate the representation of problem situations. Although substantial benefits are claimed for this approach, it embeds serious theoretical and pedagogical flaws, notably by separating the problem behaviour from the structure alleged to cause it, by ignoring scale and timing of behaviour, and by excluding the fundamental and unavoidable properties of asset stock accumulation. Policy‐makers are thus unlikely to be provided with actionable solutions, whether from feedback diagrams alone or from subsequent simulation models, a failure that may have irretrievably alienated a significant fraction of management who have been exposed to system dynamics. Copyright © 2004 John Wiley & Sons, Ltd.
The relationship between performance in dynamic systems and intelligence
Authors: Wittmann Werner W. , Hattrup Keith 
Published: August 2004

AbstractSystem dynamics is a field that emphasizes the complex demands on human decision‐makers and the cognitive processes that are either wired into the brain by nature or by education or that are stimulated by nurture. The world can be regarded as a complex system and it is a fascinating question how the human brain has adapted to its complexity and survived. Of considerable interest are the human dispositions or characteristics that are responsible for survival and adaptation. Are individual differences in human ability, aptitude, personality, or knowledge the origin of failures and successes in complex environments? These constructs are at the center of much research in psychology and cognitive sciences. Much controversy has revolved around whether dispositions like intelligence or situational constraints and characteristics of the environment are the most important predictive and explanatory constructs. The present work describes recent psychological research on working memory, intelligence, and performance on complex tasks. This research shows that intelligence, combined with personality and interests, are indeed constructs of impressive power in predicting performance. Implications of this research for selecting, educating, and training managers and decision‐makers in charge of handling such complex systems are proposed and elaborated. Copyright © 2004 John Wiley & Sons, Ltd.
YIHn: A New Family of Metal‐rich Hydride Halides
Authors: Ryazanov Mikhail , Simon Arndt , Mattausch Hansjürgen 
Published: August 2004

AbstractThe graphite‐like yttrium hydride halides, YIHn (0.8 ⩽ n ⩽ 1.0), have been prepared in quantitative yields by heating either YI3, YH2 (1:2) or stoichiometric YI3, YH2, Y mixtures in sealed Ta ampoules at 900°C. A lower limit of the homogeneity range, n ≈ 2/3, has been determined from dehydrogenation experiments. All YIHn phases adopt the ZrBr‐type heavy‐atom structure. The hydrogen variation is accompanied by a change in the c lattice constant from 31.162(3) to 31.033(1) Å for n = 0.61(3) to 1.02(3). The YIHn phases reversibly react with hydrogen at 400‐600°C to form the light green transparent compound YIH2. However, increasing the reaction temperature above 700°C causes decomposition to an unidentified phase being in equilibrium with YH2 and YI3. The arrangement of the heavy atoms in YIH2 (P $\bar 3$m1; a = 3.8579(3) Å, c = 10.997(1) Å) corresponds to a four‐layer I‐Y‐Y‐I slab with the stacking sequence (AbaB) as was found by x‐ray powder diffraction data refinement with the Rietveld method. A miscibility gap exists between YIH and YIH2.Samples YIHn (n ⩽ 1.0) show metallic conductivity at room temperature, which changes into semiconducting behavior with decreasing temperature as n approaches its lower value ≈ 2/3.
Synthesis and Structure of a Bipyridyldicarboxylate Connected Neodyminum Organic Framework
Authors: Schoknecht Birk , Kempe Rhett 
Published: August 2004

AbstractThe porous neodymium coordination polymer {[L3Nd2(H2O)4] (LH2 = 2,2′‐bipyridine‐5,5′‐dicarboxylic acid)} (1) was prepared via a hydrothermal synthesis approach starting from Nd(NO3)3·6H2O and 2,2′‐bipyridine‐5,5′‐dicarboxylic acid in a one to one mixture of ethanol and water at 160°C. The product was characterized by single crystal X‐ray diffraction, TGA and elemental analysis. Space group: P$\bar 1$, a: 6.0294(4), b: 10.9061(6), c: 13.8392(9) Å, α: 101.486(7), β: 93.799(8)°, γ: 100.933(7)°, R1 [> 2σ (I)] = 0.0147, wR2 (all data) = 0.0328. The structure determination revealed 1 to be a 3‐dimensional network with eight‐coordinated lanthanide centres acting as 5‐connectors and two types of bipyridyldicarboxylate cross‐linkers, as 3‐ and a 4‐connectors. After the loss of water – two per neodymium atom‐channels are formed with a channel diameter of 4.82 Å [atom to atom distances (Nd‐O)].
Nd2(SeO3)2(SeO4) · 2H2O – a Mixed‐Valence Compound containing Selenium in the Oxidation States +IV and +VI
Authors: Berdonosov P. S. , Schmidt P. , Dityat'yev O. A. , Dolgikh V. A. , Lightfoot P. , Ruck Michael 
Published: August 2004

AbstractPale pink crystals of Nd2(SeO3)2(SeO4) · 2H2O were synthesized under hydrothermal conditions from H2SeO3 and Nd2O3 at about 200 °C. X‐ray diffraction on powder and single‐crystals revealed that the compound crystallizes with the monoclinic space group C 2/c (a = 12.276(1) Å, b = 7.0783(5) Å, c = 13.329(1) Å, β = 104.276(7)°). The crystal structure of Nd2(SeO3)2(SeO4) · 2H2O is an ordered variant of the corresponding erbium compound. Eight oxygen atoms coordinate the NdIII atom in the shape of a bi‐capped trigonal prism. The oxygen atoms are part of pyramidal (SeIVO3)2− groups, (SeVIO4)2− tetrahedra and water molecules. The [NdO8] polyhedra share edges to form chains oriented along [010]. The selenate ions link these chains into layers parallel to (001). The layers are interconnected by the selenite ions into a three‐dimensional framework. The dehydration of Nd2(SeO3)2(SeO4) · 2H2O starts at 260 °C. The thermal decomposition into Nd2SeO5, SeO2 and O2 at 680 °C is followed by further loss of SeO2 leaving cubic Nd2O3.
A Novel One‐Dimensional Zinc Coordination Polymer, [Zinc{(4,5‐ditetrazoyl)‐imidazole}{(1,10)‐phenanthroline}(H2O)]n
Authors: Zhao Hong , Ye Qiong , Wu Qian , Song Yu‐Mei , Liu Yu‐Juan , Xiong Ren‐Gen 
Published: August 2004

AbstractThe reaction of 4,5‐dicyanoimidazole with ZnCl2 and NaN3 in the presence of (1,10)‐phenanthroline and water affords a novel one‐dimensional zinc coordination polymer, [zinc{(4,5‐ditetrazoyl)‐imidazole}{(1,10)‐phenanthroline}(H2O)]n (1), in which 1 contains a ditetrazole ligand and strongly supports the Demko‐Sharpless' tetrazole synthesis reaction. The structure was determined by single crystal X‐ray diffraction. Crystal data: P21/n; a = 11.908(18); b = 8.133(10); c = 21.01(3) Å; β = 112.46(7)°; V = 1880(1) Å3; Z = 4; R1 = 0.0882, wR2 = 0.2091.
Er2S[SiO4]: Ein Erbiumsulfid‐ortho‐Oxosilicat mit ungewöhnlicher Sulfidionen‐Koordination
Authors: Hartenbach Ingo , Lauxmann Petra , Schleid Thomas 
Published: August 2004

AbstractBei der Umsetzung von Cadmiumsulfid mit den Elementen Erbium und Schwefel in evakuierten Kieselglasampullen fallen als Nebenprodukt stäbchenförmige, rosafarbene Kristalle von Er2S[SiO4] an, welche durch Einkristallstrukturanalyse charakterisiert wurden. Die Titelverbindung kristallisiert orthorhombisch in der Raumgruppe Cmce (a = 1070,02(8), b = 1235,48(9), c = 683,64(6) pm) mit acht Formeleinheiten in der Elementarzelle. Die Kristallstruktur enthält neben isolierten ortho‐Oxosilicat‐Einheiten [SiO4]4− zwei kristallographisch unterschiedliche Er3+‐Kationen, die beide achtfach von sechs Sauerstoff‐ und zwei Schwefelatomen koordiniert sind. Die Sulfid‐Anionen werden ihrerseits von vier Er3+‐Kationen sehr verzerrt tetraedrisch umgeben. Diese exzentrischen [SEr4]10+‐Tetraeder bilden durch Ecken‐ und Kantenverknüpfung Schichten gemäß $^{2}_{\infty}{[{\rm SEr}_{4/2}]}^{4+}$ aus, die parallel (010) verlaufen und zwischen denen sich die isolierten ortho‐Oxosilicat‐Tetraeder anordnen.
Synthese und Kristallstrukturen von heteronuklearen AgI/FeII‐Koordinationspolymeren: (Me3PhN)2[Ag2Fe(SCN)6], (Me3PhN)6[Ag6Fe3(ECN)18] (E = S, Se) und (Me3PhN)4[Ag2Fe(SCN)8]
Authors: Gerber Stefan , Krautscheid Harald , Gelbrich Thomas , Vollmer Heike 
Published: August 2004

AbstractBei der Reaktion von AgSCN mit (Me3PhN)3[Fe(NCS)6] in DMF bilden sich die SCN−‐verbrückten, zweidimensional polymeren, heteronuklaren Komplexe (Me3PhN)2[Ag2Fe(SCN)6] (1) und (Me3PhN)6[Ag6Fe3(SCN)18]·CH2Cl2·DMF (2a), während bei Zugabe von (Me3PhN)(SCN) zur Reaktionslösung der kettenförmige Komplex (Me3PhN)4[Ag2Fe(SCN)8] (3) entsteht. Die zu 2a homologe Selenocyanatverbindung 2b konnte ebenfalls erhalten werden. Die Einkristall‐Röntgenstrukturanalysen zeigen, dass die Ag+‐Ionen in 1 und 2a tetraedrisch von vier S‐Atomen, in 3 von einem N‐ und drei S‐Atomen der verbrückenden SCN−‐Liganden koordiniert sind, an die Fe2+‐Ionen binden die SCN−‐ bzw. SeCN−‐Liganden stets über die N‐Atome in oktaedrischer Anordnung.