bluuebunny/crossref_metadata_2025_split huggingface dataset:
Heart rate variability and experimentally induced pain in healthy adults: A systematic review
Authors: Koenig J. , Jarczok M.N. , Ellis R.J. , Hillecke T.K. , Thayer J.F. 
Published: August 2013

AbstractBackgroundReactivity of the autonomic nervous system to experimental pain stimuli has been extensively studied using measures of heart rate and blood pressure. Heart rate variability (HRV) attempts to tease out the relative contributions of sympathetic and parasympathetic activity in the autonomic control of the heart and may therefore be more appropriate to investigate autonomic response to short‐term nociceptive stimulation in detail. The current evidence on HRV and experimentally induced pain has not yet been synthesized within a systematic review.MethodEnglish articles indexed in PubMed, EMBASE, Psyndex, PsycINFO, CINAHL and the Cochrane Library were reviewed for eligibility under pre‐specified inclusion criteria. Studies were included when they reported empirical work on autonomic response (specifically, HRV) to experimentally induced pain in healthy adults. The method of pain induction, the methodological features of HRV analysis (time domain and frequency domain measures), as well as pain and HRV‐related findings were derived from the studies.ResultsThe search revealed a total of 20 publications eligible for inclusion. Key results demonstrate an increase in sympathetic‐baroreflex activity and a decrease in vagal‐parasympathetic activity as reflected by changes in frequency domain measures of HRV.ConclusionHRV has several advantages compared to other measures of autonomic reactivity in studies investigating physiological response to nociceptive stimulation. Future studies should focus on comparisons between different methods of pain induction, interindividual variability in pain sensitivity by baseline autonomic activity, and the implications of both on the use of HRV within routine clinical evaluations.
Underlying the Mechanism of Vancomycin and Human Serum Albumin Interaction: A Biophysical Study
Authors: Wu Junlong , Wei Rong , Wang Huirui , Li Tong , Ren Weihua 
Published: August 2013

ABSTRACTIn the present study, the binding mechanism of vancomycin with human serum albumin (HSA) was determined. Upon addition of vancomycin to HSA, the fluorescence emission was quenched and the binding constant of vancomycin with HSA was found to be 6.05 × 103 M−1 at 295 K, which corresponds to –2.16 × 104 J·mol−1 of free energy. The conformation of HSA was altered upon binding of vancomycin with a decrease in α helix and an increase in β sheets and random coils, suggesting partial unfolding of the secondary structure. Molecular docking experiments found that vancomycin binds strongly with HSA at the hydrophobic pocket through hydrogen bonding and van der Waals interactions. An average binding distance of 4.71 nm has been determined on the basis of the Förster resonance energy theory. It was demonstrated that vancomycin binding to HSA causes protein structural changes. © 2013 Wiley Periodicals, Inc. J BiochemMol Toxicol 27:463‐470, 2013; View this article online at wileyonlinelibrary.com. DOI 10.1002/jbt.21511
RAFT Controlled Synthesis of Biodegradable Polymer Brushes on Graphene for DNA Binding and Release
Authors: Liu Jixian , Liu Zhen , Luo Xiong , Zong Xidan , Liu Jingquan 
Published: August 2013

The preparation of biodegradable and positively charged graphene–polymer nanocomposite for DNA uptake and release is presented. A pyrene‐terminated poly(2‐(dimethylamino) ethyl acrylate) is firstly synthesized via reversible addition–fragmentation chain transfer (RAFT) polymerization, followed by the attachment onto the graphene surface via the π–π stacking interaction. The positively charged polymer brushes benefit the uptake of the negatively charged DNA fragment via static interaction and the built‐in disulfide linkage between the polymer chain and graphene surface allows the biodegradable release of DNA in the presence of reducing agents. X‐ray photoelectron spectroscopy manifests the binding of DNA molecules to the polymer chains and agarose gel electrophoresis confirms the release of DNA.
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Determination of Poly(4,4′‐diphenylsulfonyl terephthalamide) Crystalline Structure Via WAXD and Molecular Simulations
Authors: Zhang Yumei , Wang Huaping , Chen Shenghui , Wang Xiaofeng , Fang Dufei , Burger Christian , Che Justin , Li Xiaowei , Hsiao Benjamin S. 
Published: August 2013

The crystal structure of poly(4,4′‐diphenylsulfonyl terephthalamide) (pt‐PSA) is studied by X‐ray diffraction and molecular simulation. Although the number of observed reflections is limited to warrant a precise determination of the unit cell structure and symmetry, a reasonable monoclinic unit cell is suggested with dimensions of a = 0.645 nm, b = 0.488 nm, c = 3.010 nm, and γ = 122.5°. A twofold molecule with two monomeric units forming a large zigzag conformation satisfies the X‐ray diffraction data. A layer structure is formed in the crystal phase, which is stabilized by the hydrogen bond between NH and CO and the parallel‐displaced π–π stacking from the distortional coplanarity of the benzene rings and amide group.
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Controlled Drug Release from Weakly Crosslinked Molecularly Imprinted Networks: The Benefit of Living Radical Polymerization
Authors: Salian Vishal D. , Byrne Mark E. 
Published: August 2013

This work focuses on the complex relationship between molecularly imprinted polymer network formation, network structure, and composition, and template binding and transport. A comprehensive study of template binding and transport is performed using two different reaction schemes (living radical polymerization and conventional free radical polymerization) while altering template concentration, functional monomer concentration, solvent content, crosslinking monomer length, and extent of crosslinking. Imprinted poly(HEMA‐co‐DEAEM‐co‐PEG200DMA) networks prepared by living radical polymerization (LRP) exhibit enhanced molecular imprinting and have significantly higher template binding affinities (≈2×), higher binding capacities (≈2.3×), slower template release, and lower template diffusion coefficients (1/2×) compared with imprinted polymers prepared via free radical polymerization (FRP) with statistically similar parameters for non‐imprinted polymers. A synergistic effect between LRP and molecular imprinting is demonstrated. LRP has a profound structural effect on the network leading to reduced free volume and/or increased homogeneity in the mesh structure leading to enhanced macromolecular memory. In addition, by altering reaction parameters, like template and monomer concentrations, the template binding and release characteristics can be tuned. By using an LRP reaction scheme, improved control over release can be achieved enhancing the role the molecular imprinting technique can make in the design and engineering of novel drug delivery materials.
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Red‐Light‐Induced Cationic Photopolymerization: Perylene Derivatives as Efficient Photoinitiators
Authors: Xiao Pu , Dumur Frédéric , Graff Bernadette , Gigmes Didier , Fouassier Jean Pierre , Lalevée Jacques 
Published: August 2013

Nine different perylene derivatives are prepared and their ability to initiate, when combined with an iodonium salt (and optionally N‐vinylcarbazole), a ring‐opening cationic photopolymerization of epoxides under very soft halogen lamp irradiation is investigated. One of them is particularly efficient under a red laser diode exposure at 635 nm and belongs now to the very few systems available at this wavelength. The photochemical mechanisms are studied by steady‐state photolysis, electron spin resonance spin trapping, fluorescence, cyclic voltammetry, and laser flash photolysis techniques.
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Polydiacetylene‐Peptide 1D Nanomaterials
Authors: Diegelmann Stephen R. , Tovar John D. 
Published: August 2013

Polydiacetylenes have received intense attention on account of their well‐established chromic alterations that are detectable often by the naked eye, making them ideal for a variety of applications such as biosensory materials. These polymers have been fabricated in a variety of materials platforms including 3D crystals, 2D monolayers, and 0D spherical vesicles; however, 1D morphologies that might be useful for directional energy migration are less common. This article describes the development and current research efforts of protein‐based 1D nanowire‐like supramolecular assemblies with embedded polydiacetylenes.image
Sigma‐2 Receptor Ligands and Their Perspectives in Cancer Diagnosis and Therapy
Authors: Huang Yun‐Sheng , Lu He‐Lin , Zhang Lang‐Jun , Wu Zongwen 
Published: August 2013

AbstractThe sigma‐2 receptor is highly expressed in various rapidly proliferating cancer cells and regarded as a cancer cell biomarker. Selective sigma‐2 ligands have been shown to specifically label the tumor sites, induce cancer cells to undergo apoptosis, and inhibit tumor growth. Sigma‐2 ligands are potentially useful as cancer diagnostics, anticancer therapeutics, or adjuvant anticancer treatment agents. However, both the cloning of this receptor and the identification of its endogenous ligand have not been successful, and the lack of structural information has severely hindered the understanding of its physiological roles, its signaling pathways, and the development of more selective sigma‐2 ligands. Recent data have implicated that sigma‐2 binding sites are within the lipid rafts and that PGRMC1 (progesterone receptor membrane component 1) complex and sigma‐2 receptor may be coupled with EGFR (epidermal growth factor receptor), mTOR (mammalian target of rapamycin), caspases, and ion channels. Due to its promising applications in cancer management, there are rapidly increasing research efforts that are being directed into this field. This review article updates the current understanding of sigma‐2 receptor and its potential physiological roles, applications, interaction with other effectors, with special focuses on the development of sigma‐2 ligands, their chemical structures, pharmacological profiles, applications in imaging and anticancer therapy.
Modeling Complexes of Transmembrane Proteins: Systematic Analysis of ProteinProtein Docking Tools
Authors: Kaczor Agnieszka A. , Selent Jana , Sanz Ferran , Pastor Manuel 
Published: August 2013

AbstractProteinprotein docking methodology is frequently used to model complexes of transmembrane proteins, in particular oligomers of G protein‐coupled receptors (GPCRs), even if its applicability for these systems has never been fully validated. The aim of this work is to perform a systematic study on the suitability of some widely‐used proteinprotein docking software for modeling complexes of transmembrane proteins. In this study we tested the programs ZDOCK, ClusPro, HEX, GRAMM‐X, PatchDock, SymmDock, and HADDOCK, using a set of membrane protein oligomers for which the 3D structure has been obtained experimentally, including opsin dimer, the recently published chemokine CXCR4 and kappa opioid receptor dimers. The results show that the docking success depends on the applied docking algorithm and scoring functions, but also on inherent structural features of the transmembrane proteins. Thus, proteins with large interface surfaces, rich in surface cavities, high‐order symmetry, and small conformational change upon complex formation are well predicted more often than proteins without these features. The results of this systematic analysis provide guidelines that can be used for obtaining reliable models of transmembrane proteins, including GPCRs. Therefore they can be useful for the application of structure‐based methods in drug discovery projects involving these targets.
The Mechanisms of Detachment of Mushroom‐Shaped Micro‐Pillars: From Defect Propagation to Membrane Peeling
Authors: Afferrante Luciano , Carbone Giuseppe 
Published: August 2013

AbstractThe detachment mechanisms of adhesive micro‐structured surfaces based on mushroom‐shaped micro‐pillars are analyzed. The detachment of a single mushroom shaped pillar takes place as a consequence of destabilization of an interfacial void whose size increases following a crack‐like propagation process. When the radius of the crack exceeds the pillar radius, the detachment process enters the so‐called plate regime governed by bending effect in the plate. This regime is strongly unstable and characterized by strong reduction of adhesion strength. As the crack moves further, membrane stresses in the plate become dominant and the detachment process enters the so called membrane regime, which resembles the peeling of an axisymmetric membrane. During this process the peeling line linearly increases with the radius of the crack, thus leading to an almost proportional increase of the strength of adhesion.
Automatically inf − sup compliant diamond‐mixed finite elements for Kirchhoff plates
Authors: Perotti L.E. , Bompadre A. , Ortiz M. 
Published: August 2013

SUMMARYWe develop a mixed finite‐element approximation scheme for Kirchhoff plate theory based on the reformulation of Kirchhoff plate theory of Ortiz and Morris [1]. In this reformulation the moment‐equilibrium problem for the rotations is in direct analogy to the problem of incompressible two‐dimensional elasticity. This analogy in turn opens the way for the application of diamond approximation schemes (Hauret et al. [2]) to Kirchhoff plate theory. We show that a special class of meshes derived from an arbitrary triangulation of the domain, the diamond meshes, results in the automatic satisfaction of the corresponding inf − sup condition for Kirchhoff plate theory. The attendant optimal convergence properties of the diamond approximation scheme are demonstrated by means of the several standard benchmark tests. We also provide a reinterpretation of the diamond approximation scheme for Kirchhoff plate theory within the framework of discrete mechanics. In this interpretation, the discrete moment‐equilibrium problem is formally identical to the classical continuous problem, and the two differ only in the choice of differential structures. It also follows that the satisfaction of the inf − sup condition is a property of the cohomology of a certain discrete transverse differential complex. This close connection between the classical inf − sup condition and cohomology evinces the important role that the topology of the discretization plays in determining convergence in mixed problems. Copyright © 2013 John Wiley & Sons, Ltd.
Synthesis of Small Combinatorial Libraries of Natural Products: Identification and Quantification of New Long‐chain 3‐Methyl‐2‐alkanones from the Root Essential Oil of Inula helenium L. (Asteraceae)
Authors: Radulović Niko S. , Denić Marija S. , Stojanović‐Radić Zorica Z. 
Published: August 2013

ABSTRACTIntroductionRecently, a potent anti‐staphylococcal activity of Inula helenium L. (Asteraceae) root essential oil was reported. Also, bioassay guided fractionation of the oil pointed to eudesmane sesquiterpene lactones and a series of unidentified constituents as the main carriers of the observed activity.ObjectiveTo identify nine new constituents (long‐chain 3‐methyl‐2‐alkanones) from a fraction of this root essential oil with a low minimum inhibitory concentration value (0.8 µg/mL) by employing a synthetic methodology that leads to the formation of a small combinatorial library of these compounds.MethodsThe identity of these constituents was inferred from mass spectral fragmentation patterns and GC retention data. A library of 3‐methyl‐2‐alkanones (C11–C19 homologous series) was synthesised in three steps starting from methyl acetoacetate and the corresponding alkyl halides. The synthetic library was also screened for in vitro anti‐microbial activity.ResultsGas chromatographic analyses of I. helenium essential oil samples with spiked compounds from the synthesised library corroborated the tentative identifications of the long‐chain 3‐methyl‐2‐alkanones. The availability of these anti‐microbial compounds from this library made it possible to construct GC/FID calibration curves and determine their content in the plant material: 0.08 − 24.2 mg/100 g of dry roots.ConclusionThe small combinatorial library approach enabled the first unequivocal identification of long‐chain 3‐methyl‐2‐alkanones as plant secondary metabolites, and, also, allowed determination of not only a single compound and biological properties, but those of a group of structurally related compounds. Copyright © 2013 John Wiley & Sons, Ltd.
Modification of structure and luminescence of ZnO nanopowder by the laser shock‐wave treatment
Authors: Zhyrovetsky V. , Kovalyuk B. , Mocharskyi V. , Nikiforov Yu. , Onisimchuk V. , Popovych D. , Serednytski A. 
Published: August 2013

AbstractThe paper presents the results of the ZnO nanopowder modification investigation by means of laser shock‐wave treatment. The peculiar effects of such treatment were studied at the energy density rate of ∼108–109 W/cm2. The ZnO nanopowder properties were explored by using such methods as X‐ray diffraction analysis (XRD), scanning electron microscopy and also by photoluminescence spectra decomposition analysis. The XRD study of ZnO nanopowder sample revealed its crystalline structure with the typical hexagonal wurtzite phase. It was also proved that laser shock‐wave treatment allows to essentially changing the aggregation level of nanopowder. Additionally, the photoluminescence spectra changes of ZnO naopowders were explored both under air ambient and vacuum for the initial and laser shock‐wave treated nanopowder. The decreasing intensity of green photoluminescence band and increasing intensity of the peak λ =430 nm was observed when ambient air pressure decreases. The registered changes of visible emission are referred to the modification of defect structure, especially oxygen defects. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Vapour phase epitaxy of Cu2O on a‐plane Al2O3
Authors: Wagner Alexander , Scherg‐Kurmes Harald , Waag Andreas , Bakin Andrey 
Published: August 2013

AbstractWe present a vapour phase based approach for the epitaxial growth of Cu2O with the utilization of elemental copper and oxygen as precursor materials. At present the implementation of MOCVD approach is hampered by the absence of the chemical source of Cu with high enough vapour pressure at reasonable temperatures. Moreover, the use of elemental precursors has the advantage of less impurity incorporation during growth opposed to chemical vapour based growth methods. The influence of process parameters on the growth is discussed. High resolution X‐ray diffraction measurements reveal the growth of mainly the two (002) and (220) Cu2O orientations. Precise control of the growth parameters provides the reproducible growth of pure Cu2O phase without additional CuO formation. Epitaxial growth of Cu2O is demonstrated on a‐plane Al2O3 in the temperature range of 730 °C–870 °C. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Growth of “moth‐eye” ZnO nanostructures on Si(111), c‐Al2O3, ZnO and steel substrates by pulsed laser deposition
Authors: Sandana Vinod E. , Rogers David J. , Teherani Ferechteh Hosseini , Bove Philippe , Molinari Michael , Troyon Michel , Largeteau Alain , Demazeau Gérard , Scott Colin , Orsal Gaelle , Drouhin Henri‐Jean , Ougazzaden Abdallah , Razeghi Manijeh 
Published: August 2013

AbstractSelf‐forming, vertically‐aligned, arrays of black‐body‐like ZnO moth‐eye nanostructures were grown on Si(111), c‐Al2O3, ZnO and high manganese austenitic steel substrates using Pulsed Laser Deposition. X‐ray diffraction (XRD) revealed the nanostructures to be well‐crystallised wurtzite ZnO with strong preferential c‐axis crystallographic orientation along the growth direction for all the substrates. Cathodoluminescence (CL) studies revealed emission characteristic of the ZnO near band edge for all substrates. Such moth‐eye nanostructures have a graded effective refractive index and exhibit black‐body characteristics. Coatings with these features may offer improvements in photovoltaic and LED performance. Moreover, since ZnO nanostructures can be grown readily on a wide range of substrates it is suggested that such an approach could facilitate growth of GaN‐based devices on mismatched and/or technologically important substrates, which may have been inaccessible till present. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Influence of surface roughness on Ge nanowire growth by MBE
Authors: Bansen Roman , Schmidtbauer Jan , Juda Uta , Markurt Toni , Teubner Thomas , Heimburger Robert , Boeck Torsten 
Published: August 2013

Abstractmagnified imageSignificant substrate‐dependent variations in germanium nanowire (NW) growth by molecular beam epitaxy (MBE) were found, although nominally identical substrates were used. To investigate this phenomenon, the surfaces of Ge(111) wafers polished with different polishing cloths and different pressures during planarization were studied. Characterization by means of atomic force microscopy (AFM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) revealed differences in surface roughness, which has an influence on the respective catalyst droplets' areal densities. These differences, however, manifest on larger scales and can only be determined by statistical evaluation of sufficiently large areas on the sample. This led to the conclusion, that even minor surface irregularities from chemical‐mechanical polishing (CMP) on otherwise atomically flat substrates can have a paramount influence on NW growth, if the scale on which these irregularities occur matches the scale or distance of the used catalyst droplets. It is assumed that small protrusions on the surface serve as pinning points to the droplets. This behavior promotes the vertical growth of NWs and avoids lateral movement of droplets or classical island formation. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Advances in semiconductor nanowire growth on graphene
Authors: Mazid Munshi A. , Weman Helge 
Published: August 2013

Abstractmagnified imageHere we review the recent research activities on the epitaxial growth of semiconductor nanowires (NWs) on graphene substrates. Semiconductor NWs with quasi one‐dimensional structure have become an active research field due to their various interesting physical properties and potentials for future electronic and optoelectronic device applications, such as transistors, sensors, solar cells, light emitting diodes, and lasers. At almost the same time graphene, a two‐dimensional material made of carbon, was discovered and has gained an ever increasing interest during the last few years owing to its remarkable properties, including excellent electrical conductivity, optical transparency, and mechanical strength and flexibility. A hybrid structure by epitaxially growing semiconductor NWs on graphene could provide a new avenue for the development of future advanced NW‐based flexible electronic and optoelectronic devices. We address the challenges for the growth of semiconductor NWs on graphene, with a special focus on the III–V semiconductors, and highlight some potential applications of the NW/graphene hybrid system. (© 2013 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Mobile satellite reception with DVB‐SH receiver architecture and performance
Authors: Gómez Amaia Añorga , Lipp Stefan , Leyh Martin , Niemann Bernhard 
Published: August 2013

SUMMARYWithin the Digital Video Broadcasting (DVB) family of standards, DVB‐SH (satellite to handheld devices) is the first standard for a hybrid system offering parallel reception of satellite and terrestrial signals. In this paper, we discuss the architecture and implementation of a full‐featured DVB‐SH receiver. In addition, a laboratory test bed including a DVB‐SH signal generator that can be used for DVB‐SH system validation and receiver characterization is presented. We provide some key results of receiver performance measurements in typical channel conditions. Finally, we highlight the advantage of a multi‐frequency network configuration in case of a hybrid reception scenario. Copyright © 2013 John Wiley & Sons, Ltd.