bluuebunny/crossref_metadata_2025_split huggingface dataset:
Computational study of the relationship between the flow resistance and the microscopic structure of polymer monoliths
Authors: Deridder Sander , Eeltink Sebastiaan , Desmet Gert 
Published: July 2011

AbstractThe present article reports on a numerical study of the permeability and flow resistance of ordered and random‐structured polymer monolith mimics with different structures. Comparing the permeability of the different monolith structures with the same domain size and the same external porosity, it is found that the larger the degree of globule clustering, the lower is the resulting permeability. More or less independently of the external porosity, a 40% decrease in permeability is observed when comparing a purely cylindrical branch‐type skeleton with a strongly clustered globular skeleton with the same external porosity. Correlations allowing to estimate the flow resistance as a function of the external porosity are presented for each considered degree of globule clustering.
Fabrication of Polyaniline: Nail/Spindle‐Shaped Morphology
Authors: Leng Wenguang , Zhou Shuxue , Wu Limin 
Published: July 2011

AbstractNail/spindle‐shaped polyaniline is synthesized by chemically oxidizing aniline with ammonium persulfate in a near‐neutral aqueous medium using PVP as the stabilizing agent. The type of dispersing agent, APS content and aniline concentration have obvious impacts on the morphology of the resulting polyaniline. Typically, in the concentration ranges of 1.5–6 × 10−4 M PVP and 0.02–0.05 M aniline and for molar ratios [APS]:[aniline] of 0.4:1 to 0.8:1, nail/spindle‐shaped polyaniline can be obtained. A possible mechanism is proposed to elucidate the formation process.magnified image
Dextran‐Based Polycations: Thermodynamic Interaction with Water as Compared With Unsubstituted Dextran, 2 – Flory/Huggins Interaction Parameter
Authors: Bercea Maria , Nichifor Marieta , Eckelt John , Wolf Bernhard A. 
Published: July 2011

AbstractThe Flory‐Huggins interaction parameterχis determined as a function of volume fraction of polymerφby vapor‐pressure measurements at 25, 37.5 and 50 °C for five dextran samples that differ inf, the fraction of randomly distributed charged monomer units. The functionχ(φ) has a minimum that is shifted towards lowerχvalues asfincreases. The higher the temperature, the more the individual curves fan out. The heats of dilution at high polymer concentrations change from exothermal to endothermal asfincreases. The results can be well modeled by an approach accounting explicitly for chain connectivity and conformational changes. A smooth transition of the solution properties upon the random introduction of charged units into dextran is observed.magnified image
A Supramolecular Polymer of Nitroxide Radicals via Hydrogen Bonding
Authors: Nakajima Satoshi , Kato Eisuke , Minatozaki Masayuki , Nishide Hiroyuki 
Published: July 2011

AbstractSummary: 2,2,6,6‐Tetramethylpiperidinyl‐N‐oxy (TEMPO) is a robust nitroxide radical molecule under ambient conditions. We found that the TEMPO derivatives act as a proton acceptor to form an intermolecular hydrogen‐bonding complex with many kinds of phenol or urea derivatives. ORTEP analysis of the crystals of TEMPO with the phenol derivatives indicated that hydrogen bonding could be formed between the oxygen of the nitroxide and the phenolic proton and the NO bond of the hydrogen‐bonded TEMPO was lengthened in comparison to that of the free NO bond. The formation constant of the hydrogen‐bonding complex of TEMPO with the phenol or urea derivatives in a chloroform solution was spectroscopically determined by IR to be 10–100 M−1. Hydrogen bonding of the thelechelic bis‐TEMPO derivatives with thelechelic bis‐phenol or bis‐urea derivatives provided a supramolecular structure. The estimated molecular weights of the supramolecules in the chloroform solution, based on DOSY‐NMR spectroscopy, were 3000–4000. The potential of the nitroxide radical's supramolecule as a new functional material is also described.
Polymer‐Metal Nanoparticle Complexes for Improving the Performance of Liquid Crystal Displays
Authors: Toshima Naoki 
Published: July 2011

AbstractSummary: Here we applied metal nanoparticles as a dopant of liquid crystals. Since liquid crystal molecules are self‐assembled, it is not so easy to disperse metal nanoparticles in liquid crystal media. We first prepared metal nanoparticles protected by liquid crystal molecules by reduction of metal ions in the presence of liquid crystal molecules. This liquid crystal molecule‐protected metal nanoparticles can be easily dispersed in liquid crystal media to fabricate liquid crystal sol containing metal nanoparticles. A simple liquid crystal molecule, 4′‐pentylbiphenyl‐4‐carbonitrile (abbreviated as 5CB) was used in the present experiments at first. 5CB sol containing metal nanoparticles could construct novel twisted nematic liquid crystal devices (TN‐LCDs), which revealed the electrooptic properties depending on the kind of metal of nanoparticles. During the experiments we discovered that 5CB‐protected metal nanoparticles could move in liquid crystal media by applying the voltage. This phenomenon is inconvenient for liquid crystal displays, especially those driven by a matrix of thin‐film transistors (TFTs). In order to avoid this phenomenon, we prepared polymer‐protected metal nanoparticles and applied them to liquid crystal devices, which provided good performance as the devices, i.e., low driving voltage, rapid response at low temperature, and so on.
Further Studies on Homo‐ and Copolymerization of Styrene through Metallocenic Initiator Systems
Authors: Rabagliati Franco M. , Pérez Mónica A. , Rodríguez Francisco J. , Cancino Rodrigo A. , Crispel Nocolas , Mardones Gabriela A. , Muñoz Héctor E. , Saavedra Marcela A. , Vidal Manuel , Muñoz Lisa A. 
Published: July 2011

AbstractSummary: Binary metallocene‐MAO and ternary diphenylzinc‐metallocene‐MAO initiator systems have been tested as initiators in the homopolymerization of styrene and also in its copolymerization with several diverse comonomers including substituted styrenes, styrene derivatives, α‐olefins and dienes. Various titanocenes and zirconocenes and some exploratory experiment with hafnocene were carried out. The results indicate that titanocenes were more effective than zirconocenes in the homopolymerization of styrene while zirconocenes did better in α‐olefin polymerization. It was found that titanocenes generated mainly syndiotactic polystyrene, s‐PS, while zirconocenes yielded atactic polystyrene or, depending on the zirconocene, a low percentage of s‐PS. For these types of initiators the polymerization process depends largely on the inductive effect of the substituents linked to the benzene ring of styrene and on its position (ortho, meta or para). Substituent multiplicity reduced markedly the effectiveness of these initiator systems. Styrene/isoprene polymerization was also studied using binary zirconocene‐MAO initiator systems that yielded low conversions and also low molecular weight polymers.
Metal Ion Removal Properties of Water‐Insoluble Functional Polymers
Authors: Rivas Bernabé L. , Muñoz Carla 
Published: July 2011

AbstractSummary: Resins containing sulfonic acid groups by radical polymerization were synthesized. The metal ion retention properties were studied by batch and column methods for the polluting metal ions Cd(II), Pb(II), and Hg(II).pH exercises an important effect on the retention: the metal ion sorption increases with increases in the pH. The maximum retention capacity was determined after three contacts at optimum pH. Resin R1 obtained the highest value 1.207 mmol/g resin for Cd(II). Different eluent reagents were used to recover the resin. Resin R1 loaded with Pb(II) was completely recovered using 4 M HCl as stripping reagent.
Complexes of Water‐Soluble Polymers with Cu2+ and Ag+ as Antibacterial Agents
Authors: Rivas Bernabé L. , Pereira Eduardo , Guzmán Catherine , Maureira Antonio 
Published: July 2011

AbstractSummary: The potential application of polymers in the biomedical area is huge, especially as antimicrobial agent. We studied the recovery of metal ions (silver and copper) with a known antibacterial activity. Using the liquid‐phase polymer‐based retention, LPR, technique it was generated the polymer‐metal complexes from these metal ions. Their antibacterial activity was studied for gram‐positive and gram‐negative bacteria. The results indicated that the anionic polymers easily yield polymer‐metal complexes with increased antibacterial activity with respect to their polymers. Cationic polymers demonstrated efficient antibacterial activity, and the polymer metal‐complexes, PMC, showed similar antibacterial results. Neither system presented a genotoxic effect.
[Cu(H2btec)(bipy)]∞: Reusable Metal Organic Polymer Catalyst for Epoxidation Reactions
Authors: Aguirre Pedro , Brown Kareen , Venegas‐Yazigi Diego , Paredes‐García Verónica , Spodine Evgenia 
Published: July 2011

AbstractSummary: The search of new inorganic materials with better catalytic properties is an important field of research. Reusability, efficiency and atom economy correspond to the main parameters to characterize a catalyst. In this work, we inform the effectiveness of [Cu(H2btec)(bipy)]∞ (H4btec = 1,2,4,5‐benzenetetracarboxylic acid) as an heterogeneous coordination polymer catalyst for the oxidation of olefins. The catalyst exhibits good atom economy, high turnover numbers and good selectivity for a ratio of 4000/1 substrate/catalyst for cyclohexene and styrene oxidation. Furthermore, the catalyst was recycled and reused for seven consecutive cycles, retaining the structural integrity and effectiveness as catalyst in all the performed experiments.
A Novel Coordination Polymer Based on Decavanadate Units Linked by Copper(II) Ethylenediamine Complexes
Authors: Venegas‐Yazigi Diego , Hermosilla‐Ibáñez Patricio , Costamagna Juan , Spodine Evgenia , Vega Andrés , Paredes‐García Verónica , Le Fur Eric 
Published: July 2011

AbstractSummary: A novel coordination polymer[{Cu(en)2}(V10O28)]n · 2n[Cu(en)2(H2O)] · 2n(H3BO3) ·  2n(H2O) was obtained by hydrothermal reaction. The compound crystallizes in the monoclinic crystal system, in the C2/c space group, with a = 26.490 (3) Å; b = 11.6558 (11) Å; c = 19.8426 (19) Å; β = 124.011 (1)°; V = 5078.6(8) Å3. The solid structure is formed by polymeric chains, [Cu(en)2(H2O)]2+ cations, and boric acid and water solvate molecules, stabilized through a multiple hydrogen bond network.
Redox‐Responsive Metallo‐Supramolecular Polymers and Gels Containing bis‐Terpyridine Appended Cyclam Ligand
Authors: Gasnier Aurélien , Bucher Christophe , Moutet Jean‐Claude , Royal Guy , Saint‐Aman Eric , Terech Pierre 
Published: July 2011

AbstractSummary: Soluble coordination polymers and gels built from a polytopic ligand containing two terpyridine units linked by a azamacrocyclic group are presented. This system originally incorporates two different types of metal complexes in the same polymer chain which induces remarkable electrochromic properties and a rare redox triggered reversible sol‐gel transition.
Characterization of PVC‐Tetraruthenated Metalloporphyrins Modified Electrodes: Application as Electrocatalyst in the Nitrite Reduction
Authors: Calfumán Karla , Dreyse Paulina , García Camilo , Aguirre Maria J. , Beltrán Tomás , Guillamón Eva , Sorribes Iván , Vicent Cristian , Llusar Rosa , Isaacs Mauricio 
Published: July 2011

AbstractSummary: This paper describes the electrochemical reduction of nitrite ion in 0.1 M NaClO4, on glassy carbon or ITO electrodes modified with mixtures PVC‐ tetraruthenated metalloporphyrins. This electrode is able to keep the extraordinary electrocatalytic properties of the macrocycle allowing multielectronic transfers and a great stability as a consequence of the inclusion of the macrocycles into a polymeric support such as PVC. On the other hand, the electrochemical reduction of nitrite ion on these modified electrodes studied by cyclic voltammetry shows an enhancement in the current values and lower overpotential compared with the activity of the bare glassy carbon electrode. Controlled potential electrolysis experiments verify the production of ammonia, hydrazine and hydroxylamine, showing the electrocatalytic character and the stability of this modified electrode.
Effect of Perylene as Electron Acceptor and poly(tetrabromo‐p‐phenylene Diselenide) as “Buffer Layer” on Heterojunction Solar Cells Performances
Authors: Godoy Alicia , Cattin Linda , Bernède Jean Christian , Díaz Fernando , del Valle Mará Angélica 
Published: July 2011

AbstractSummary: Perylene derivatives, that behave as liquid crystal and might be used as electron acceptors, and poly(tetrabromo‐p‐phenylenediselenide) (PTBrPDSe) were synthesized with the purpose of using the polymer as buffer layer in solar cells. It was demonstrated that perylene compounds of N,N′‐diheptyl‐3,4,9,10‐perylentetracarboxyldiimide (PTCDI‐C7) and N,N′‐diundecyl‐3,4,9,10‐perylentetracarboxyldiimide (PTCDI‐C11) enabled obtaining photovoltaic effect when coupled with copper phthalocyanine (CuPc). The power conversion efficiency of the cells prepared from these perylenes is similar, whatever the x value. However this efficiency is smaller than the one achieved when the couple CuPc/C60 (fullerene) is used. More precisely, the best efficiency was obtained when a PTBrPDSe/Au buffer layer is introduced between the ITO anode and the CuPc. It was established that the presence of the thin PTBrPDSe layer allows improving the shunt resistance and consequently the cells performance.
Complexing Polymer Films in The Preparation of Modified Electrodes for Detection of Metal Ions
Authors: Pereira Eduardo , Rivas Bernabé L. , Heitzman Marie , Moutet Jean‐Claude , Bucher Christophe , Royal Guy , Aman Eric Saint 
Published: July 2011

AbstractSummary: The complexing properties of poly (3‐(pyrrol‐1‐yl)propylmalonic acid) (poly1) and poly(N,N′‐ethylenebis[N‐[(3‐(pyrrole‐1‐yl)propyl) carbamoyl) methyl]‐glycine (poly2) coated electrodes (C|poly1 and C|poly2) towards Cu(II), Pb(II), Hg(II) and Cd(II) cations using the open circuit chemical preconcentration‐anodic stripping technique were studied. Sorption process of metal cations onto complexing surfaces was readily investigated through the combination of a chemical pre‐concentration‐anodic stripping technique with a Langmuir isotherm model. The modified electrodes were used for the voltammetric determination of Cu(II), Pb(II), Hg(II) and Cd(II) ions, giving low detection limits for Cu(II) (5 × 10−9 mol L−1) and Pb(II) (5 × 10−10 mol L−1). The ability of the modified electrodes to analyze Cu(II) ions in natural sample has been demonstrated by the analysis of a tap water sample. The results of the preconcentration process under competitive conditions clearly shows that the selectivity of complexing molecular electrode materials can be subtly tuned upon playing on the accumulation time, polymer thickness and/or memory effect of the binding polymers, opening up new avenues towards evolutive and efficient smart sensing materials.
A Comprehensive Decision Approach for Rubber Tree Planting Management in Africa
Authors: Diaby Moussa , Ferrer Hélène , Valognes Fabrice , Clement‐Demange André 
Published: July 2011

ABSTRACTThe main objective of this study is to settle a rigorous field of decision analysis for rubber tree clones selection. Nowadays, there does not exist any process based upon a rigorous method to select the best clone to be plant in order to get the highest return on investment. The only known selection method is to use the experience of different protagonists acting in the plantation. So, we need a tool that takes into account very important criteria in order to achieve the main objective. This goal is achieved by using multicriterion analysis methods to the clone selection. The ranking procedure uses Elimination and Choice Expressing the Reality (ELECTRE III). For each criterion, indifference and preference thresholds are determined after establishing the relative importance of each criterion including rubber tapping, cumulative production during 15 years, cumulative production between 15 and 25 years, wind resistance, disease resistance, physiological resistance, grafting and quality of the rubber. Copyright © 2011 John Wiley & Sons, Ltd.
Prescription of teriparatide in the UK — a nationwide register study from 2004 to 2008
Authors: Abhishek Abhishek , Pande Ira , Hubbard Richard B 
Published: July 2011

ABSTRACTIntroductionThe objectives were to ascertain the incidence of teriparatide prescription in the UK stratified by region and sex, examine the association between National Institute for Health and Clinical Excellence (NICE) and European Medicines Agency approval and geographic variation in teriparatide prescription, and compare the regional rates of teriparatide and oral bisphosphonate use.MethodsHealthcare at Home provided anonymized information on age, sex, year, and treating hospital for all UK residents commenced on teriparatide between 1 January 2004 and 31 December 2008. The crude and age‐ and sex‐adjusted rates of teriparatide prescription were calculated for each region. Rates of teriparatide prescription for each region, in the year before and in the year after approval by NICE and European Medicines Agency, were compared in a multiplicative model (likelihood‐ratio test) for women and men, respectively. The number of patients on oral bisphosphonates in each region was estimated from quantity of oral bisphosphonates dispensed in 2007.ResultsCompared with that in England, the incidence of teriparatide prescription was 54% and 50% higher in Wales and in Scotland, respectively. The Northeast and East of England had lowest rate of teriparatide use. There was significant geographic variation in increase in teriparatide prescription in women after favorable NICE recommendation (p = 0.0001). In contrast, prescription rates in men increased uniformly across the UK (p = 0.15). Geographic variation in oral bisphosphonate prescription did not mirror that of teriparatide.ConclusionWe report wide geographic variation in teriparatide prescription rates within the UK. In a country with government‐funded health care, reasons for this inequality need to be identified. Copyright © 2011 John Wiley & Sons, Ltd.
Prescription patterns of patients diagnosed with schizophrenia in mental hospitals in Tashkent/Uzbekistan and in four German cities
Authors: Mundt Adrian P. , Aichberger Marion C. , Fakhriddinov Sardor , Fayzirahmanova Maria , Grohmann Renate , Heinz Andreas , Ivens Sebastian , Magzumova Shakhnoza , Sartorius Norman , Ströhle Andreas 
Published: July 2011

ABSTRACTPurposeLittle is known about psychopharmacological prescription practice in low‐income countries. The present study aimed for an analysis of pharmacological treatment strategies for inpatients with schizophrenia in Tashkent, the capital city of Uzbekistan, facing a low‐income situation as compared with four German cities in a high‐income Western situation.MethodsWe conducted a cross‐sectional quantitative survey of age, gender, diagnoses, and psychotropic medication of 845 urban psychiatric inpatients of the Tashkent psychiatric hospital and of 922 urban psychiatric inpatients in four German cities on 1 day in October 2008. We compared the current treatment strategies for specific diagnostic categories between the two settings.ResultsIn Tashkent, patients diagnosed with schizophrenia were treated with clozapine (66%), haloperidol (62%), or both (44%). More than one‐third of the patients treated for schizophrenia were prescribed amitriptyline. The usual treatment strategy for schizophrenia was the combination of two or more antipsychotics (67%). In German cities, the preferred antipsychotics for the treatment of schizophrenia were olanzapine (21%), clozapine (20%), quetiapine (17%), risperidone (17%), and haloperidol (14%); the most common treatment strategy for patients with schizophrenia was the combination of antipsychotics and benzodiazepines; 44% of the patients were treated with two or more antipsychotics at a time.ConclusionsIn both settings, psychotropic combination treatments are common for the treatment of schizophrenia contrasting current guideline recommendations. Its rationale and effectiveness needs to be tested in further studies. Copyright © 2011 John Wiley & Sons, Ltd.
Die Versuchung bunter Bilder
Authors: Vollmer Michael , Möllmann Klaus‐Peter , Pinno Frank 
Published: July 2011

AbstractGebäudethermographie mit Infrarotkameras wird immer populärer, da eine gute thermische Isolation der Häuser zunehmend gefragt ist. Ihre bunten Falschfarbenbilder sind aussagekräftig, führen aber bei fehlender Fachkenntnis zu massiven Fehlinterpretationen. Infrarotkameras erfassen nur einen Ausschnitt aus dem Infrarotspektrum strahlender Körper. Grundsätzlich muss man das Emissionsverhalten der aufgenommenen Körper und das Absorptionsverhalten der Luft zwischen diesen und der Kamera kennen. Eine richtige Bildinterpretation erfordert zudem Kenntnisse über den Standort, Abschattungen, das Wetter und die Aufheizung sonnenbeschienener Flächen in den Tagen zuvor. In der Regel sind Innenaufnahmen eher aussagekräftig. Neben der Beurteilung der Wärmeisolation eignet sich die Thermographie auch, um verborgene Strukturen wie etwa verputztes Fachwerk oder Heizungsrohre sichtbar zu machen.
Licht im Schneckentempo
Authors: Horn Wolfgang , Denz Cornelia 
Published: July 2011

AbstractLangsames Licht verspricht in vielen Bereichen der Photonik und optischen Datenkommunikation Vorteile. Es kann in verschiedenen Systemen wie etwa Quantengasen, bei Streuprozessen und in optischen Filtern auftreten. Entscheidend ist eine spektrale Änderung des imaginären Brechungsindexes durch starke Dispersion für das Licht. Bisher konnten jedoch nicht alle wichtigen Faktoren in einem System vereint werden, die für eine Anwendung benötigt werden. Kurze Lichtpulse, wie sie attraktiv für die Datenverarbeitung sind, erfordern zum Beispiel eine sehr hohe Bandbreite. Hinzu kommen die Miniaturisierung, Durchstimmbarkeit und möglichst geringe Dämpfung des Systems.
Logik aus atomaren Spins
Authors: Wiebe Jens , Khajetoorians Alexander Ako , Chilian Bruno , Wiesendanger Roland 
Published: July 2011

AbstractDie Nano‐Spintronik verfolgt das Ziel, den Elektronenspin in Atomen oder Molekülen nutzbar zu machen, um Bauelemente der Informationstechnologie kleiner, schneller, energieeffizienter, und kompatibel mit nichtflüchtigen Speichern zu gestalten. Unserer Forschungsgruppe an der Universität Hamburg ist es gelungen, ein logisches Gatter zu bauen, das aus nur elf atomaren Spins besteht. Damit wurde ein vielversprechendes Konzept für zukünftige Nano‐Spintronik‐Bauteile demonstriert.
Von Bällen und Schlägern
Authors: Vollmer Michael , Möllmann Klaus‐Peter 
Published: July 2011

AbstractBälle sind eines der beliebtesten Spielzeuge von Kindern und Erwachsenen. Aus physikalischer Sicht haben alle Ballspiele eines gemeinsam: mehr oder minder stark deformierbare Bälle kollidieren mit Oberflächen. Die Physik vollständig elastischer Kollisionen beinhaltet zwar nur recht elementare Physik. In der Praxis sind Kollisionen jedoch praktisch nie hundertprozentig elastisch, und außerdem laufen die Prozesse so schnell ab, dass Details nur mit Hochgeschwindigkeitsaufnahmen sichtbar werden.
Jetzt geht's um die Wurst
Authors: Vilgis Thomas 
Published: July 2011

AbstractWährend der Grillsaison haben Bockwurst, Wiener, Frankfurter und Bratwurst Hochsaison. Als Beigut landen diese Fleischprodukte auf Grills oder in dampfenden Wurstkesseln. Diesen Produkten sind zwei Eigenschaften gemein: Ihre quasi zylinderähnliche Form und ihr Aufplatzen in Form eines länglichen Spannungsrisses – sofern deren Gartemperatur zu hoch wird. Die “Kesselformel” für zylinderförmige, dünnwandige Kessel erklärt das universelle Platzen.