bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Verdier Hypercovering Theorem
Authors: Jardine J. F. 
Published: May 2011

AbstractThis note gives a simple cocycle-theoretic proof of the Verdier hypercovering theorem. This theorem approximates morphisms [X, Y] in the homotopy category of simplicial sheaves or presheaves by simplicial homotopy classes of maps, in the case where Y is locally fibrant. The statement proved in this paper is a generalization of the standard Verdier hypercovering result in that it is pointed (in a very broad sense) and there is no requirement for the source object X to be locally fibrant.
A Generalised Kummer-Type Transformation for the pFp(x) Hypergeometric Function
Authors: Miller A. R. , Paris R. B. 
Published: May 2011

AbstractIn a recent paper, Miller derived a Kummer-type transformation for the generalised hypergeometric function pFp(x) when pairs of parameters differ by unity, by means of a reduction formula for a certain Kampé de Fériet function. An alternative and simpler derivation of this transformation is obtained here by application of the well-known Kummer transformation for the confluent hypergeometric function corresponding to p = 1.
La publicidad institucional en la arena parlamentaria española
Authors: Feliu-Albaladejo Ángeles 
Published: May 2011

El presente artículo presenta los resultados de un estudio acerca de la presencia de la publicidad institucional en el Congreso de los Diputados, tomado como una de las arenas de la comunicación política. La investigación se centra en el análisis de las iniciativas parlamentarias presentadas y en los debates parlamentarios correspondientes, con especial incidencia en las iniciativas legislativas previas a la Ley de Publicidad y Comunicación Institucional de 2005, y su valor como antecedente de otras normas reguladoras. La primera proposición de ley, aun resultando rechazada, sería tomada como base documental en posteriores propuestas de diferentes fuerzas políticas. La postura de los distintos grupos, y los argumentos que la justifican, ponen de manifiesto una más que clara falta de coherencia en muchos casos. La comparación entre diferentes iniciativas en distintas cámaras españolas -y los debates en torno a ellas- supone un primer paso en el establecimiento de la policy memory, que, trascendiendo el caso concreto de la publicidad institucional, se muestra como un instrumento sumamente útil en el ámbito de la investigación en Comunicación Política.
Ultrasmooth Gold Films via Pulsed Laser Deposition
Authors: Ng Doris K. T. , Bhola Bipin S. , Bakker Reuben M. , Ho Seng‐Tiong 
Published: May 2011

AbstractA simple, one step technique for depositing ultrasmooth gold films using pulsed laser deposition is demonstrated by optimizing process para­meters. The smoothest film having a root‐mean‐square roughness of 0.17 nm (including the substrate roughness of 0.11 nm) for a 35 nm thick film on a silicon substrate are obtained by introducing a nitrogen flow in the chamber during deposition. We postulate that the reduction in surface roughness caused by nitrogen gas pressure in the chamber is due to the force of the gas flow acting against the flow of the plasma plume containing Au atoms. The gas acts as a filter that reduces the kinetic energy of the gold adatoms. This is the best result reported so far for a single step deposition of gold. It is a step towards low‐loss planar gold films for surface plasmon applications.
Tunable Crystallinity in Regioregular Poly(3‐Hexylthiophene) Thin Films and Its Impact on Field Effect Mobility
Authors: Aiyar Avishek R. , Hong Jung‐Il , Nambiar Rakesh , Collard David M. , Reichmanis Elsa 
Published: May 2011

AbstractThe properties of poly(alkylthiophenes) in solution are found to have a profound impact on the self assembly process and thus the microstructural and electrical properties of the resultant thin films. Ordered supramolecular precursors can be formed in regioregular poly(3‐hexylthiophene) (P3HT) solutions through the application of low intensity ultrasound. These precursors survive the casting process, resulting in a dramatic increase in the degree of crystallinity of the thin films obtained by spin coating. The crystallinity of the films is tunable, with a continuous evolution of mesoscale structures observed as a function of ultrasonic irradiation time. The photophysical properties of P3HT in solution as well in the solid state suggest that the application of ultrasound leads to a π stacking induced molecular aggregation resulting in field effect mobilities as high as 0.03 cm2 V−1 s−1. A multiphase morphology, comprising short quasi‐ordered and larger, ordered nanofibrils embedded in a disordered amorphous phase is formed as a result of irradiation for at least 1 min. Two distinct regions of charge transport are identified, characterized by an initial sharp increase in the field effect mobility by two orders of magnitude due to an increase in crystallinity up to the percolation limit, followed by a gradual saturation where the mobility becomes independent of the thin film microstructure.
Copper‐Catalyzed Aromatic Trifluoromethylation via Group Transfer from Fluoral Derivatives
Authors: Kondo Hideaki , Oishi Masahiro , Fujikawa Kenichi , Amii Hideki 
Published: May 2011

AbstractStarting from a readily available fluoral derivative, catalytic aromatic trifluoromethylation has been successfully achieved. A small amount of copper(I) iodide‐phenanthroline complex catalyzed the cross‐coupling reactions of aryl/heteroaryl iodides with the O‐silylated hemiaminal of fluoral (trifluoroacetaldehyde) to provide trifluoromethylated arenes in moderate to high yields.
A New Class of Heterogeneous Platinum Catalysts for the Chemoselective Hydrogenation of Nitroarenes
Authors: Pandarus Valerica , Ciriminna Rosaria , Béland François , Pagliaro Mario 
Published: May 2011

AbstractA new series of nanostructured platinum catalysts able to catalyze the selective reduction of nitroarenes has been developed. The materials, made of organosilica physically doped with nanostructured platinum(0), are stable and efficient. Reactions in general proceed with high yield and often go to completion, while the catalysts can be reused in further reaction runs. This establishes a new class of relevant solid catalysts for synthetic organic chemistry named SiliaCat Platinum‐Hydrogel.
Regioselective Addition of Organometallic Reagents to 2‐(1‐Alkynyl)‐2‐alken‐1‐ones for an Efficient Synthesis of Substituted 1,2‐Allenyl Ketones
Authors: Yu Xiuzhao , Zhang Junliang 
Published: May 2011

AbstractHighly substituted 1,2‐allenyl ketones can be easily and efficiently prepared from organometallic reagents and readily available 2‐(1‐alkynyl)‐2‐alken‐1‐ones. The synthetic application of 1,2‐allenyl ketone products was also showcased by palladium‐catalyzed further transformation.
Syndio‐ and Isoselective Coordinative Chain Transfer Polymerization of Styrene Promoted by ansa‐Lanthanidocene/ Dialkylmagnesium Systems
Authors: Sarazin Yann , de Frémont Pierre , Annunziata Liana , Duc Michel , Carpentier Jean‐François 
Published: May 2011

AbstractCombinations of the discrete neutral allyl ansa‐lanthanidocenes {Me2C(Cp)(Flu)}Nd[1,3‐ (SiMe3)2C3H3] and rac‐{Me2C(Ind)2}Y[1,3‐ (SiMe3)2C3H3] with di(n‐butyl)magnesium constitute efficient binary catalytic systems for the stereocontrolled coordinative chain transfer polymerization of styrene, yielding near‐perfect syndio‐ and isospecific polystyrenes, respectively, with high activities and productivities. By adjusting the amount of di(n‐butyl)magnesium, up to 200 polymer chains can be generated per lanthabide center, and good control of the molecular weight features enables the tailoring of low to medium molecular weight polymers.
A Novel Mode of Reactivity for Gold(I): The Decarboxylative Activation of (Hetero)Aromatic Carboxylic Acids
Authors: Cornella Josep , Rosillo‐Lopez Martin , Larrosa Igor 
Published: May 2011

AbstractGold(I) salts are found to mediate the decarboxylation of a variety of aromatic and heteroaromatic carboxylic acids at significatively lower temperatures (as low as 60 °C) than the currently used copper(I) (180–190 °C) and silver(I) (80–140 °C) systems. In contrast to silver(I)‐ and copper(I)‐mediated decarboxylations, the resulting aryl‐gold(I) complexes are stable towards protodemetallation and can be readily isolated.
Integrated High‐Efficiency Pt/Carbon Nanotube Arrays for PEM Fuel Cells
Authors: Zhang Weimin , Minett Andrew I. , Gao Mei , Zhao Jie , Razal Joselito M. , Wallace Gordon G. , Romeo Tony , Chen Jun 
Published: May 2011

AbstractA facile strategy to deposit Pt nanoparticles with various metal‐loading densities on vertically aligned carbon nanotube (ACNT) arrays as electrocatalysts for proton exchange membrane (PEM) fuel cells is described. The deposition is achieved by electrostatic adsorption of the Pt precursor on the positively charged polyelectrolyte functionalized ACNT arrays and subsequent reduction by L‐ascorbic acid. The application of the aligned electrocatalysts in fuel cells is realized by transferring from a quartz substrate to nafion membrane using a hot‐press procedure to fabricate the membrane electrode assembly (MEA). It is shown that the MEA with vertically aligned structured electrocatalysts provides better Pt utilization than that with Pt on conventional carbon nanotubes or carbon black, resulting in higher fuel cell performance.
Functional and Evolutionary significance of the recruitment and firing patterns of the jaw adductors during chewing in verreaux's sifaka (Propithecus verreauxi)
Authors: Hylander William L. , Vinyard Christopher J. , Wall Christine E. , Williams Susan H. , Johnson Kirk R. 
Published: May 2011

AbstractJaw‐muscle electromyographic (EMG) patterns indicate that compared with thick‐tailed galagos and ring‐tailed lemurs, anthropoids recruit more relative EMG from their balancing‐side deep masseter, and that this muscle peaks late in the power stroke. These recruitment and firing patterns in anthropoids are thought to cause the mandibular symphysis to wishbone (lateral transverse bending), resulting in relatively high symphyseal stresses. We test the hypothesis that living strepsirrhines with robust, partially fused symphyses have muscle recruitment and firing patterns more similar to anthropoids, unlike those strepsirrhines with highly mobile unfused symphyses. Electromyographic (EMG) activity of the superficial and deep masseter, anterior and posterior temporalis, and medial pterygoid muscles were recorded in four dentally adult Verreaux's sifakas (Propithecus verreauxi). As predicted, we find that sifaka motor patterns are more similar to anthropoids. For example, among sifakas, recruitment levels of the balancing‐side (b‐s) deep masseter are high, and the b‐s deep masseter fires late during the power stroke. As adult sifakas often exhibit nearly complete symphyseal fusion, these data support the hypothesis that the evolution of symphyseal fusion in primates is functionally linked to wishboning. Furthermore, these data provide compelling evidence for the convergent evolution of the wishboning motor patterns in anthropoids and sifakas. Am J Phys Anthropol 2011. © 2011 Wiley‐Liss, Inc.
Forward dynamic simulation of bipedal walking in the Japanese macaque: Investigation of causal relationships among limb kinematics, speed, and energetics of bipedal locomotion in a nonhuman primate
Authors: Ogihara Naomichi , Aoi Shinya , Sugimoto Yasuhiro , Tsuchiya Kazuo , Nakatsukasa Masato 
Published: May 2011

AbstractJapanese macaques that have been trained for monkey performances exhibit a remarkable ability to walk bipedally. In this study, we dynamically reconstructed bipedal walking of the Japanese macaque to investigate causal relationships among limb kinematics, speed, and energetics, with a view to understanding the mechanisms underlying the evolution of human bipedalism. We constructed a two‐dimensional macaque musculoskeletal model consisting of nine rigid links and eight principal muscles. To generate locomotion, we used a trajectory‐tracking control law, the reference trajectories of which were obtained experimentally. Using this framework, we evaluated the effects of changes in cycle duration and gait kinematics on locomotor efficiency. The energetic cost of locomotion was estimated based on the calculation of mechanical energy generated by muscles. Our results demonstrated that the mass‐specific metabolic cost of transport decreased as speed increased in bipedal walking of the Japanese macaque. Furthermore, the cost of transport in bipedal walking was reduced when vertical displacement of the hip joint was virtually modified in the simulation to be more humanlike. Human vertical fluctuations in the body's center of mass actually contributed to energy savings via an inverted pendulum mechanism. Am J Phys Anthropol, 2011. © 2011 Wiley‐Liss, Inc.
Lichtmikroskopie mit Doughnut‐Moden: ein Konzept zur Detektion, Charakterisierung und Manipulation einzelner Nanoobjekte
Authors: Züchner Tina , Failla Antonio Virgilio , Meixner Alfred J. 
Published: May 2011

AbstractLasermoden mit ringförmigem Strahlprofil, die zumeist als Doughnut‐Moden (DMs) bezeichnet werden, finden Anwendung in unterschiedlichen Forschungsbereichen wie den Bio‐ und Materialwissenschaften oder der Einzelmolekülmikroskopie und ‐spektroskopie. Der Hauptgrund für die wachsende Bedeutung der DMs liegt darin, dass in letzter Zeit die Techniken zur Herstellung dieser Moden mit hoher Präzision verfeinert oder wiederentdeckt wurden. Obwohl ihr Potential bisher noch nicht vollkommen ausgeschöpft wird, ermöglichen die speziellen Polarisationseigenschaften der DMs eine Vielzahl von Anwendungen. So tragen sie dazu bei, unser grundlegendes Verständnis der optischen Eigenschaften einzelner emittierender Spezies wie Moleküle, Nanopartikel oder Quantenpunkte zu vervollständigen und erlauben Einblick in die dreidimensionale Dipol‐ oder Partikelorientierung im Raum. Durch ihre vollständig verschwindende Intensität im Zentrum des Fokus eignen sich einige DMs auch für die stimulierte Emissionslöschung in der Fluoreszenzmikroskopie. Aus demselben Grund hat man sie auch für die Verwendung in optischen Fallen und Pinzetten vorgeschlagen.
SUMO meets meiosis: An encounter at the synaptonemal complex
Authors: Watts Felicity Z. , Hoffmann Eva 
Published: May 2011

AbstractRecent discoveries have identified the small ubiquitin‐like modifier (SUMO) as the potential ‘missing link’ that could explain how the synaptonemal complex (SC) is formed during meiosis. The SC is important for a variety of chromosome interactions during meiosis and appears ladder‐like. It is formed when ‘axes’ of the two homologous chromosomes become connected by the deposition of transverse filaments, forming the steps of the ladder. Although several components of axial and transverse elements have been identified, how the two are connected to form the SC has remained an enigma. Recent discoveries suggest that SUMO modification underlies protein‐protein interactions within the SC of budding yeast. The versatility of SUMO in regulating protein‐protein interactions adds an exciting new dimension to our understanding of the SC and suggests that SCs are not homogenous structures throughout the nucleus. We propose that this heterogeneity may allow differential regulation of chromosome structure and function.
Pluronic F68 enhanced the conformational stability of salmon calcitonin in both aqueous solution and lyophilized solid form
Authors: Lee Ting‐Huei , Lin Shan‐Yang 
Published: May 2011

AbstractThe effects of different surfactants on the conformational stability and structural similarity of salmon calcitonin (sCT) in aqueous solution and lyophilized forms were investigated by using microscopic Fourier transform infrared (FTIR) spectroscopy with second‐derivative spectral analysis. Six surfactants, HCO‐60, sodium dodecyl sulfate (SDS), Tween 80, PEG 400, Pluronic 68, and F127 were selected. The sCT aqueous solution with or without different surfactants was, respectively, incubated at 40°C for up to 35 h. sCT films were casted on the CaF2 plates and IR spectra were collected as a function of incubation time. Second derivative analysis showed that the native sCT having a major α‐helical structure was gradually changed to the combination of α‐helix, random coil, and β‐sheet conformations in aqueous solution at 40°C. Similar conformational changes with delayed β‐sheet formation were obtained for sCT after co‐incubation with all the surfactants except Pluronic F68. When the native sCT was freeze‐dried alone, a marked conformational alteration was found as illustrated by a poor spectral correlation coefficient (r) value of 0.823 as compared to that of the unlyophilized native sCT. This r value was significantly deviated from 1, strongly indicating the influence of lyophilization stress on the surfactant‐free sCT. The r value for sCT after lyophilizing with HCO‐60, Pluronic F127, PEG 400, or Pluronic F68 was >0.9, suggesting the possible stabilization of these surfactants in the lyophilization process. The sCT sample after lyophilizing with Pluronic F68 showed a highest r value (>0.968), indicating the most optimal stabilization effect of Pluronic F68 for sCT sample via lyophilization. Pluronic F68 was found to be the preferential surfactant for preventing the secondary structure changes in aqueous solution at 40°C as well as in lyophilized powder. © 2011 Wiley Periodicals, Inc. Biopolymers 95: 785‐791, 2011.
Isovaline in naturally occurring peptides: A nondestructive methodology for configurational assignment
Authors: De Zotti Marta , Biondi Barbara , Crisma Marco , Hjørringgaard Claudia U. , Berg Albrecht , Brückner Hans , Toniolo Claudio 
Published: May 2011

AbstractThe nonproteinogenic, Cα‐tetrasubstituted, helicogenic, chiral α‐amino acid isovaline (Iva) is remarkably spread in the biosphere. Together with its achiral, lower homolog α‐aminoisobutyric acid (Aib), it represents a characteristic marker of a class of naturally occurring peptide antibiotics, for which the acronym “peptaibiotics” became established. In these peptides, Iva occurs as the (S)‐(= L) or the (R)‐(= D) enantiomer, but peptide sequences containing both Iva enantiomers are also common. Here, we applied our recently developed 1H‐NMR method, which enables the nondestructive assignment of the configuration of each Iva residue in a peptide of known helical screw sense, to natural and synthetic peptaibiotics. Our method proved to be generally applicable and provided evidence that, in the peptaibiotic bergofungin A, the Iva12 configuration is (R) and not (S) as reported previously. Moreover, we extended our NMR method by including a 13C‐NMR parameter. A statistical analysis of the preferred main‐ and side‐chain conformations of the Iva residues in peptides, performed based on their published X‐ray diffraction structures, allowed us to provide a sound rationale to the NMR criteria exploited to establish the configuration of this amino acid. © 2011 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 98: 36–49, 2012.
Sacral nerve stimulation increases activation of the primary somatosensory cortex by anal canal stimulation in an experimental model
Authors: Griffin K M , Pickering M , O'Herlihy C , O'Connell P R , Jones J F X 
Published: May 2011

Abstract

Background
Sacral and posterior tibial nerve stimulation may be used to treat faecal incontinence; however, the mechanism of action is unknown. The aim of this study was to establish whether sensory activation of the cerebral cortex by anal canal stimulation was increased by peripheral neuromodulation.

Methods
A multielectrode array was positioned over the right primary somatosensory cortex of anaesthetized rats. A brief burst of electrical stimulation was applied to either the left sacral root or the left posterior tibial nerve, and evoked potentials from anal canal stimulation were signal-averaged at intervals over 1 h. At the end of the experiment, the cerebral cortex was removed and probed for polysialylated neural cell adhesion molecule (PSA-NCAM).

Results
Sacral nerve root and posterior tibial nerve stimulation significantly increased the peak amplitude of primary cortical evoked potentials by 54·0 and 45·1 per cent respectively. This change persisted throughout the period of observation. The density of PSA-NCAM-positive cells in the somatosensory cortex underlying the electrode array was increased by approximately 50 per cent in the sacral nerve-stimulated group.

Conclusion
Brief sacral neuromodulation induces profound changes in anal canal representation on the primary somatosensory cortex, providing a plausible hypothesis concerning the mechanism of action of neuromodulation in the treatment of faecal incontinence.
Randomized clinical trial of epidural, spinal or patient-controlled analgesia for patients undergoing laparoscopic colorectal surgery
Authors: Levy B F , Scott M J , Fawcett W , Fry C , Rockall T A 
Published: May 2011

Abstract

Background
Epidural analgesia is considered fundamental in enhanced recovery protocols (ERPs). However, its value in laparoscopic colorectal surgery is unclear. The aim of this study was to examine the effects of different analgesic regimens on outcomes following laparoscopic colorectal surgery in fluid-optimized patients treated within an ERP.

Methods
Ninety-nine patients were randomized to receive epidural, spinal or patient-controlled (PCA) analgesia. The primary endpoints were time until medically fit for discharge and length of hospital stay. Secondary endpoints included return of bowel function, pain scores, and changes in pulmonary function and quality of life.

Results
Ninety-one patients completed the study. The median length of hospital stay was 3·7 days following epidural analgesia, significantly longer than that of 2·7 and 2·8 days for spinal analgesia and PCA respectively (P = 0·002 and P &lt; 0·001). There was also a slower return of bowel function with epidural analgesia than with spinal analgesia and PCA. Epidural analgesia did not offer better preservation of pulmonary function or quality of life, although pain scores were higher in the PCA group in the early postoperative period.

Conclusion
Many of the outcomes in the epidural analgesia group were significantly worse than those in the spinal analgesia and PCA groups, suggesting that either of these two modalities could replace epidural analgesia. Registration number: NCT 18926278 (http://www.clinicaltrials.gov).