bluuebunny/crossref_metadata_2025_split huggingface dataset:
Analysis of the ultrasonographic findings predictive of vasa previa
Authors: Hasegawa Junichi , Farina Antonio , Nakamura Masamitsu , Matsuoka Ryu , Ichizuka Kiyotake , Sekizawa Akihiko , Okai Takashi 
Published: September 2010

AbstractObjectivesTo clarify the ultrasonographic findings indicative of prenatal vasa previa.MethodsThe variables associated with placental and umbilical cord abnormalities were retrospectively analysed in cases with and without vasa previa.ResultsConsecutive subjects were divided into those with vasa previa (10) and controls (4682). Abnormal placental forms and placenta previa/low‐lying placenta were associated with vasa previa [odds ratio (OR) 21.9 and 28.0]. While the frequency of velamentous cord insertion was 1.6% in the controls, it was 90% in the cases with vasa previa (OR 552). In addition, low cord insertions in the uterus were observed in 90% of the patients with vasa previa and only in 0.4% of the controls (OR 2470). Descending cords were also frequently observed in patients with vasa previa (OR 89.8). Finally, a multivariable regression analysis demonstrated an OR of 65.1 (95% confidence interval (CI) 5.8–733) for velamentous cord insertion and an OR of 344.7 (95% CI 31–3838) for low cord insertion with regard to the risk of vasa previa.ConclusionOur results suggest that confirmation of the placental cord insertion, including not only velamentous cord insertion but also the cords located on the lower uterine segment, is the best way to detect vasa previa. Copyright © 2010 John Wiley & Sons, Ltd.
Synthesis of amorphous aliphatic polyester‐ether homo‐ and copolymers by radical polymerization of ketene acetals
Authors: Undin Jenny , Plikk Peter , Finne‐Wistrand Anna , Albertsson Ann‐Christine 
Published: September 2010

AbstractRadical ring‐opening polymerization has been efficiently used to copolymerize 2‐methylene‐1,3,6‐trioxocane (MTC) and 2‐methylene‐1,3‐dioxepane (MDO). The cyclic ketene acetal MTC was first synthesized and homopolymerized at different temperatures using either 2,2‐azobisisobutyronitrile or dicumyl peroxide as initiator. The polymerization mechanism was not temperature‐dependent, and the polymerization proceeded with 100% ring‐opening at all the temperatures evaluated. The structures of MTC and PMTC were verified by 1H‐nuclear magnetic resonance (NMR) and 13C‐NMR spectroscopies. A number‐average molecular weight of 6500 was obtained after 2 days at 70 °C in bulk, which was somewhat higher than the theoretical molecular weight. A significant amount of branching was detected from the high polydispersity index as well as the glass‐transition temperatures. The polyester‐ether was then successfully obtained by copolymerization of MTC with MDO. Different feed ratios and temperatures were used to map the reaction, and the copolymers were characterized by NMR, size exclusion chromatography, and differential scanning calorimetry. The amount of MTC within the polymer was independent of the feed ratio and always higher than the amount of MDO. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Synthesis of poly(N‐9‐ethylcarbazole‐exo‐norbornene‐5,6‐dicarboximide) for hole‐transporting layer in hybrid organic light‐emitting devices
Authors: Choi Myeon‐Cheon , Hwang Jae‐Chul , Kim Chiwan , Kim Youngkyoo , Ha Chang‐Sik 
Published: September 2010

AbstractWe synthesized new polynorbornene dicarboximide (PCaNI) functionalized with hole‐transporting carbazole moieties and its copolymer (PCaNA) by ring‐opening metathesis polymerization (ROMP), where the PCaNA was further reacted with 3‐amino‐triethoxysilane to prepare PCaNI/silica hybrid. We also investigated the feasibility of PCaNI and PCaNI/silica hybrid (PCaSi) as a hole‐transporting material for hybrid organic light emitting devices (HOLEDs). To improve the performance of the PCaNI‐based HOLEDs, N,N′‐diphenyl‐N,N′‐(3‐methylphenyl)‐[1,1′‐biphenyl]‐4‐4′‐diamine (TPD) was also introduced into the PCaNI matrix. Results showed that PCaNI exhibited high glass transition temperature (∼260 °C) and high optical transparency in the visible region. The highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of PCaNI were measured as 5.6 and 2.2 eV, while the TPD‐doped PCaNI showed 5.7 eV (HOMO) and 2.6 eV (LUMO). The PCaNI/silica hybrid nanolayers showed excellent solvent resistance due to the formation of covalent bonds between ITO and PCaNI. The HOLEDs with PCaNI/TPD or PCaSi/TPD hybrid nanolayers exhibited relatively higher luminance (∼10,000 cd/m2), lower operating voltage (∼6.5 V at 300 cd/m2), and higher current efficiency (∼2.7 cd/A). © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
One‐pot synthesis of polymeric nanoparticle by ring‐opening metathesis polymerization
Authors: Zhang Liya , Song Chunmei , Yu Jiahui , Yang Dan , Xie Meiran 
Published: September 2010

AbstractShell‐functionalized polymeric nanoparticle was prepared through the method of polymerization‐induced self‐assembly of block copolymers [poly(2,3‐bis(2‐bromoisobutyryloxymethyl)‐5‐norbornene)‐block‐poly(7‐oxanorborn‐5‐ene‐exo‐exo‐2,3‐dicarboxylic acid dimethyl ester), PBNBE‐b‐PONBDM] via one‐pot ring‐opening metathesis polymerization of 2,3‐bis(2‐bromoisobutyryloxymethyl)‐5‐norbornene (BNBE) and 7‐oxanorborn‐5‐ene‐exo‐exo‐2,3‐dicarboxylic acid dimethyl ester (ONBDM) in a selective solvent. The compositions and the molecular weights of the copolymers were estimated by 1H‐NMR and gel permeation chromatography. The micelles were characterized by dynamic light scattering, transmission electron micrograph, and atomic force microscopy. The results indicated that the spherical micelles constructed with bromine‐bearing PBNBE shell and PONBDM core were stable and reproducible in toluene. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
Synthesis and unexpected electrochemical behavior of the triphenylamine‐based aramids with ortho‐ and para‐trimethyl‐protective substituents
Authors: Yen Hung‐Ju , Guo Shiue‐Ming , Liou Guey‐Sheng 
Published: September 2010

AbstractTwo series of new organosoluble polyamides with methyl‐substituted triphenylamine (MeTPA) units showing anodically electrochromic characteristic were prepared from the phosphorylation polyamidation reaction of two diamine monomers, 4,4′‐diamino‐2″,4″,6″‐trimethyltriphenylamine (Me3TPA‐diamine; 2) and 4,4′‐diamino‐4″‐methyltriphenylamine (MeTPA‐diamine; 2′), with various dicarboxylic acids, respectively. These polymers were readily soluble in many polar solvents and showed useful levels of thermal stability associated with relatively high glass‐transition temperatures (Tg) (314–329 °C) and high char yields (higher than 62% at 800 °C in nitrogen). In addition, the polymer films showed reversible electrochemical oxidation, high coloration efficiency (CE), low switching time, and anodic green electrochromic behavior. The unexpected electrochemical behavior of higher oxidation potential and lower electrochemical stability of Me3TPA‐polyamides I than MeTPA corresponding polymers could be attributed to the higher steric hindrance of ortho‐substituents in Me3TPA moieties, thus made the resonance stabilization of cation radical much more difficult for the Me3‐substituted phenyl ring. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010
High speeds complementary integrated circuits fabricated with all‐printed polymeric semiconductors
Authors: Baeg Kang‐Jun , Khim Dongyoon , Kim Dong‐Yu , Jung Soon‐Won , Koo Jae Bon , You In‐Kyu , Yan Henry , Facchetti Antonio , Noh Yong‐Young 
Published: September 2010

AbstractInkjet‐printed high speed polymeric complementary circuits are fabricated using an n‐type ([poly{[N,N′‐bis(2‐octyldodecyl)‐naphthalene‐1,4,5,8‐bis(dicarboximide)‐2,6‐diyl]‐alt‐5,5′‐(2,2′‐dithiophene)} [P(NDI2OD‐T2), Polyera ActivInk N2200] and two p‐type polymers [poly(3‐hexylthiophene) (P3HT) and a dithiophene‐based polymer (Polyera ActivInk P2100)]. The top‐gate/bottom‐contact (TG/BC) organic field‐effect transistors (OFETs) exhibit well‐balanced and very‐high hole and electron mobilities (μFET) of 0.2–0.5 cm2/Vs, which were enabled by optimization of the inkjet‐printed active features, small contact resistance both of electron and hole injections, and effective control over gate dielectrics and its orthogonal solvent effect (selection of poly(methyl methacrylate) and 2‐ethoxyethanol). Our first demonstrated inkjet‐printed polymeric complementary devices have been integrated to high‐performance complementary inverters (gain >30) and ring oscillators (oscillation frequency ∼50 kHz). We believe that the operating frequency of printable organic circuits can be further improved more than 10 MHz by fine‐tuning of the device architecture and optimization of the p‐ and n‐channel semiconductor processing. © 2010 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2010
Insecticidal potency of novel compounds on multiple insect species of medical and veterinary importance
Authors: Kaufman Phillip E , Mann Rajinder S , Butler Jerry F 
Published: September 2010

AbstractBACKGROUND: Vector‐borne diseases continue to present significant threats to human, animal and plant health. Mosquitoes, houseflies, sand flies and stable flies are well‐known vectors of several human and animal pathogens. The toxicity of selected semiochemicals with molecular structures indicative of insecticidal activity was determined against these insect species with the aim of developing novel insecticides toxic to multiple insect species.RESULTS: Three semiochemicals, namely beta‐damascone, cyclemone A and melafleur, showed remarkable toxicity to three mosquitoes, Aedes aegypti L., Ae. albopictus (Skuse) and Anopheles quadrimaculatus Say, the housefly, Musca domestica L., the stable fly, Stomoxys calcitrans L., and the sand fly, Lutzomyia shannoni (Dyar). The chemicals were equally toxic to several field‐collected permethrin‐tolerant housefly strains. When formulated as 500 mL L−1 emulsifiable concentrates, the chemicals demonstrated stability and toxicity on filter paper and camouflage military fabrics, with persistence up to 8 days under laboratory conditions. The chemicals were equally effective under field conditions when evaluated on unpainted plywood panels, although a higher dosage was required under field conditions to achieve similar efficacy.CONCLUSION: Laboratory quantification of LC50 values and field efficacy of three semiochemicals as formulated compounds on mosquitoes, houseflies, stable flies and sand flies showed that these semiochemicals could serve as potent insecticides for multiple insect species. Copyright © 2010 Society of Chemical Industry
Predicting polaronic defect states by means of generalized Koopmans density functional calculations
Authors: Lany Stephan 
Published: September 2010

AbstractLattice defects in semiconductors and wide‐gap materials which create deep levels in an open‐shell electronic configuration can give rise to so‐called defect bound small polarons. This type of defects present a challenge for electronic structure methods because the localization of the defect state and the associated energy levels depend sensitively on the ability of the total‐energy functional to satisfy the physical condition that the energy E(N) must be a piecewise linear function of the fractional electron number N. For practical applications the requirement of a linear E(N) is re‐cast as a generalized Koopmans condition. Since most functionals do not fulfill this condition accurately, we use parameterized perturbations that cancel the non‐linearity of E(N) and recover the correct Koopmans behavior. Starting from standard density functionals, we compare two types of parameterized perturbations, i.e., the addition of on‐site potentials and the mixing of non‐local Fock exchange in hybrid‐functionals. Surveying a range of acceptor‐type defects in II–VI and III–V semiconductors, we present a classification scheme that describes the relation between hole localization and the lattice relaxation of the polaronic state.
Critical evaluation of the LDA + U approach for band gap corrections in point defect calculations: The oxygen vacancy in ZnO case study
Authors: Boonchun Adisak , Lambrecht Walter R. L. 
Published: September 2010

AbstractThe LDA + U approach can be used essentially as a shift potential to open up the band gap of a semiconductor. This approach was previously applied to the oxygen vacancy in ZnO by Paudel and Lambrecht (PL) [Phys. Rev. B 77, 205202 (2008)]. Here, we review the results of that approach and introduce additional refinements of the LDA + U model. Good agreement is obtained with recent hybrid functional calculations on the position of the ${\varepsilon} (2 + /0)$ transition state. A comparison of various approaches on the oxygen vacancy in ZnO is provided. The relevance of the one‐electron levels to the experiments is discussed.
Ab initio study of GaN periodically substituted by transition metal for intermediate band materials
Authors: Wang Jian , Xing Yucheng , Luo Yi 
Published: September 2010

AbstractThe electronic and optical properties of Gax−1(TM)Nx materials, where TM is the transition metal Sc, Ti, V, Cr, Mn and Fe, are studied with density functional theory to survey the candidates of intermediate band (IB) material. The result shows that the sub‐band formed in the GaN band gap moves from the conduction band (CB) towards the valence band (VB) as the atomic number of TM increases, and its width becomes larger with the increase of TM concentration. Ga7MnN8, Ga7FeN8, Ga15MnN16 and Ga15FeN16 exhibit partially filled IBs that are completely isolated from the CB and the VB. The absorption coefficient in sub‐band‐gap energy is greatly improved by the induction of the IB compared to the GaN host.magnified image
The calculated absorption coefficients of GaN, Ga7FeN8 and Ga15FeN16.
Molecular networks with a near zero Poisson's ratio
Authors: Grima Joseph N. , Attard Daphne 
Published: September 2010

AbstractA series of polyphenylacetylene networks are predicted to exhibit the not so common property of a near‐zero Poisson's ratio, a property which is highly desirable in various practical applications. This behaviour is explained qualitatively in terms of a simple honeycomb model involving flexure, hinging and/or stretching of acetylene chains.
Modelling and testing of a foldable macrostructure exhibiting auxetic behaviour
Authors: Grima Joseph N. , Ravirala Naveen , Galea Romina , Ellul Brian , Attard Daphne , Gatt Ruben , Alderson Andrew , Rasburn John , Evans Kenneth E. 
Published: September 2010

AbstractAuxetics exhibit the anomalous property of getting fatter rather than thinner when uniaxially stretched [negative Poisson's ratio (NPR)]. This paper presents an analytical model of a structure constructed from umbrella type sub‐units which is predicted to exhibit this property together with the results of mechanical tests of a structure having this geometry. It is shown that such systems can exhibit negative on‐axis Poisson's ratio of −1 which means that they maintain their aspect ratio, while Poisson's ratio becomes less negative for loading off‐axis. It is also shown that this model can explain the sign and anisotropy of Poisson's ratio demonstrated by a molecular level system constructed from calix(4)arenes having the same geometry.
An Essential and Evolutionarily Conserved Role of Protein Arginine Methyltransferase 1 for Adult Intestinal Stem Cells During Postembryonic Development
Authors: Matsuda Hiroki , Shi Yun-Bo 
Published: September 2010

Abstract
Organ-specific adult stem cells are critical for the homeostasis of adult organs and organ repair and regeneration. Unfortunately, it has been difficult to investigate the origins of these stem cells and the mechanisms of their development, especially in mammals. Intestinal remodeling during frog metamorphosis offers a unique opportunity for such studies. During the transition from an herbivorous tadpole to a carnivorous frog, the intestine is completely remodeled as the larval epithelial cells undergo apoptotic degeneration and are replaced by adult epithelial cells developed de novo. The entire metamorphic process is under the control of thyroid hormone, making it possible to control the development of the adult intestinal stem cells. Here, we show that the thyroid hormone receptor-coactivator protein arginine methyltransferase 1 (PRMT1) is upregulated in a small number of larval epithelial cells and that these cells dedifferentiate to become the adult stem cells. More importantly, transgenic overexpression of PRMT1 leads to increased adult stem cells in the intestine, and conversely, knocking down the expression of endogenous PRMT1 reduces the adult stem cell population. In addition, PRMT1 expression pattern during zebrafish and mouse development suggests that PRMT1 may play an evolutionally conserved role in the development of adult intestinal stem cells throughout vertebrates. These findings are not only important for the understanding of organ-specific adult stem cell development but also have important implications in regenerative medicine of the digestive tract.
Polymer‐incarcerated metal(0) cluster catalysts
Authors: Kobayashi Shū , Miyamura Hiroyuki 
Published: September 2010

AbstractPolymer‐incarcerated metal(0) nanocluster catalysts were developed based on two techniques: microencapsulation and cross‐linking. Pd, Au, Pt, and bimetallic nanoclusters could be efficiently immobilized on polymers containing benzene rings keeping subnanometer‐ to nanometer‐size clusters. Catalysts could be used for redox reactions using molecular hydrogen and oxygen, and could be reused without aggregation of nanoclusters and leaching of metals. Modification of polymers and addition of second inorganic supports sometimes increased their reactivity. © 2010 The Japan Chemical Journal Forum and Wiley Periodicals, Inc. Chem Rec 10: 271–290; 2010: Published online in Wiley InterScience (www.interscience.wiley.com) DOI 10.1002/tcr.201000026
Das Niederdruckplasma
Authors: Franz Gerhard 
Published: September 2010

AbstractNiederdruckplasmen zeichnen sich durch ungewöhnliche Eigenschaften aus, da sich lang‐ und kurzreichweitige Wechselwirkungen überlagern. Die selektive Übertragung der Energie auf die Elektronen bedingt starke Abweichungen von den thermodynamischen Gleichgewichtsbedingungen. Da sich das Plasma gegen äußere Einflüsse abschirmt, wird die Realisierung komplizierter Prozesse in einfachen Vakuumrezipienten möglich. Die wichtigste Anregungsart ist die Einkopplung von Wellen im RF‐ oder Mikrowellenbereich, die wichtigsten Technologien Sputtern und Plasmaätzen.
Glühkathoden‐Ionisationsmanometer für hohe Drücke im Vakuumbereich
Authors: Edelmann Christian 
Published: September 2010

AbstractDas Verhalten von Glühkathoden‐Ionisations‐Vakuummetern an der Meßgrenze zu hohen Drücken hin wird theoretisch und experimentell untersucht. Mit zunehmendem Druck steigt der Ionenstrom an, erreicht ein Maximum und fällt schließlich ab. Aufgrund des Maximums ergibt sich eine Doppeldeutigkeit der Drückanzeige. Diese kann durch Messung der Ionendriftgeschwindigkeit im elektrischen Feld mit Hilfe einer zusätzlichen Elektrode beseitigt werden. Mit speziellen Elektrodenkonfigurationen und geeigneten Betriebsparametern lassen sich so Drücke bis zu 1000 Pa messen.
Das Strahlrohrvakuumsystem des HERA‐Protonenringes
Authors: Trines D. 
Published: September 2010

AbstractDas Strahlrohrvakuumsystem des HERA‐Protonenringes ist 6,3 km lang. Während des Betriebes der supraleitenden Magnete befinden sich davon etwa 5,5 km auf der Temperatur von flüssigem Helium. In diesem kritischen Bereich gibt es keinerlei nachweisbare Lecks. Der Betriebsdruck liegt unter 10−12 mbar. Die bis zu 10 m langen runden Strahlrohre sind von innen mit Kupfer hoher elektrischer Leitfähigkeit beschichtet.Die verbleibenden 800 m des Systems befinden sich auf Raumtemperatur. Die Kammern haben unterschiedliche komplizierte Querschnitte, die mit hoher Genauigkeit gefertigt wurden. Trotz der zum Teil sehr beengten Platzverhältnisse ist eine in situ Ausheizung bis 300°C möglich.
Wachstum von TiN‐Schichten bei periodisch wechselnden Einfallswinkelverhältnissen der schichtbildenden Teilchen
Authors: Reinhold U. , Neidhardt A. , Puff M. , Wuttke W. 
Published: September 2010

AbstractZur reaktiven Herstellung von Hartstoffschichten bei niedrigen Substrattemperaturen wird bevorzugt das Magnetronsputtern eingesetzt. Es ist bekannt, daß sowohl das Bombardement energiereicher Teilchen, als auch die Winkelverhältnisse des Teilcheneinfalls am Substrat das Schichtwachstum wesentlich beeinflussen. Insbesondere entstehen Schichten mit offenem kolumnaren Gefüge, wenn die schichtbildenden Teilchen unter einem großen Winkel zur Substratnormalen einfallen. Diese Schichten sind zur Verschleißminderung ungeeignet.Bei der Beschichtung von Werkzeugen und Verschleißteilen ist zur Homogenisierung der Schichtdecke und zur effektiven Ausnutzung des Rezipientenvolumens eine Substratbewegung erforderlich. Diese Substratbewegung verursacht zeitlich veränderliche Einfallswinkelverhältnisse der schichtbildenden Teilchen. Es wird gezeigt, daß der Anteil der während der Substratbewegung schräg einfallenden schichtbildenden Teilchen die Schichtmorphologie stark beeinträchtigt. Inwieweit es möglich ist, durch geeignete Maßnahmen die Ausbildung des offenen kolumnaren Gefüges bei der Beschichtung realer Bauteile zu verhindern, wird diskutiert.
Vakuumfüllverfahren bei Quecksilberthermometern
Authors: Lochner K. H. , Fahrenkrog H.‐H. 
Published: September 2010

AbstractBei der Herstellung von Quecksilberthermometern wird zur Füllung mit Quecksilber seit rund 60 Jahren Vakuum angewandt. Die bisherigen Kenntnisse über die jeweils für einen bestimmten Thermometertyp nötige Auspumpdauer und den Einfluß des Ausheizens wurden empirisch gewonnen. Durch die Anwendung von Miniaturdrucksensoren wurde der Druckverlauf während des Auspumpens und der für blasenfreies Füllen der Thermometer nötige Druck im Thermometergefäß ermittelt. Als Drucksensoren wurden Glühbirnchen, die sich im Druckbereich von 0,05 bis 10 mbar als Piranimeßzellen verwenden lassen, eingesetzt. Außerdem wurde ein Computerprogramm zur Berechnung der Auspumpkurven der Thermometer entwickelt. Die mit dem Programm berechneten Auspumpkurven ließen sich gut an die experimentell erhaltenen Meßergebnisse anpassen. Mit den daraus erhaltenen Parametern für die Entgasung wurden Auspumpkurven für einige gängige Thermometertypen berechnet. Dabei zeigte sich, daß die Auspumpzeiten, die zum blasenfreien Füllen der Thermometer nötig sind, sehr stark von Duchmesser und Länge der Kapillare, dem Volumen des Thermometergefäßes und der Vorbehandlung durch Ausheizen abhängen.
Steepest descent
Authors: Meza Juan C. 
Published: September 2010

AbstractThe steepest descent method has a rich history and is one of the simplest and best known methods for minimizing a function. While the method is not commonly used in practice due to its slow convergence rate, understanding the convergence properties of this method can lead to a better understanding of many of the more sophisticated optimization methods. Here, we give a short introduction and discuss some of the advantages and disadvantages of this method. Some recent results on modified versions of the steepest descent method are also discussed. WIREs Comp Stat 2010 2 719–722 DOI: 10.1002/wics.117This article is categorized under:

Algorithms and Computational Methods > Numerical Methods