bluuebunny/crossref_metadata_2025_split huggingface dataset:
Effect of Annealing Temperature of ZnO on the Energy Level Alignment in Inverted Organic Photovoltaics (OPVs)
Authors: Sharma Anirudh , Watkins Scott E. , Andersson Gunther , Lewis David A. 
Published: April 2014

AbstractThe annealing temperature of zinc oxide (ZnO) layers was found to have a significant impact on the efficiency of inverted devices. Device efficiencies were found to increase significantly from 2.5 % to 3.6 % with an increase in the post‐deposition annealing temperature of ZnO. A systematic study of the density of states shows that the work function varies from 3.2 to 3.9 eV with annealing temperature and the offset between the conduction band of ZnO and the lowest unoccupied molecular orbital (LUMO) of the [6,6]‐phenyl‐C61‐butyric acid methyl ester (PCBM) reduced from 0.5 eV (250 °C annealing) to 0 eV (150 °C annealing) resulting in inefficient charge transport across the bulk heterojunction (BHJ) to the indium tin oxide (ITO) electrode. The dependence of the electronic properties on the annealing temperature has been attributed to a deficiency of electrons corresponding to the nonbonding (lone pair) oxygen orbitals in the ZnO matrix and the presence of precursor impurities.
The Development of Visible‐Light Photoredox Catalysis in Flow
Authors: Garlets Zachary J. , Nguyen John D. , Stephenson Corey R. J. 
Published: April 2014

AbstractVisible‐light photoredox catalysis has recently emerged as a viable alternative for radical reactions otherwise carried out with tin and boron reagents. It has been recognized that by merging photoredox catalysis with flow chemistry, slow reaction times, lower yields, and safety concerns may be obviated. While flow reactors have been successfully applied to reactions carried out with UV light, only recent developments have demonstrated the same potential of flow reactors for the improvement of visible‐light‐mediated reactions. This review examines the initial and continuing development of visible‐light‐mediated photoredox flow chemistry by exemplifying the benefits of flow chemistry compared with conventional batch techniques.
Molecular Dynamics Simulations of Bromodomains Reveal Binding‐Site Flexibility and Multiple Binding Modes of the Natural Ligand Acetyl‐Lysine
Authors: Spiliotopoulos Dimitrios , Caflisch Amedeo 
Published: April 2014

AbstractExperimental protein structures provide spatial information at the atomic level. A further dimension, time, is supplemented by molecular dynamics. Since the pioneering work on the 58‐residue inhibitor of bovine pancreatic trypsin in the group of Martin Karplus in the seventies, molecular dynamics simulations have shown that the intrinsic flexibility of proteins is essential for their function. Here, we review simulation studies of bromodomains. These protein modules are involved in the recognition of acetylated lysine side chains, a post‐translational modification frequently observed in histone tails. The molecular dynamics simulations have unmasked: (i) the large plasticity of the loops lining the acetyl‐lysine binding site (coupled to its self‐occlusion), and (ii) multiple binding modes of acetyl‐lysine. These simulation results suggest that recognition of histone tails by bromodomains is modulated by their intrinsic flexibility, and further corroborate the utility of molecular dynamics in understanding (macro)molecular recognition.
Application of a high power Yb fiber‐based laser compatible with commercial optical parametric oscillator for coherent anti‐stokes raman scattering microscopy
Authors: Hage Charles‐Henri , Boisset Simon , Ibrahim Ali , Morin Franck , Hoenninger Clemens , Grunske Tobias , SOUISSI SAMI , Heliot Laurent , Leray Aymeric 
Published: April 2014

ABSTRACTCoherent anti‐Stokes Raman scattering (CARS) microscopy is a powerful tool for chemical analysis at a subcellular level, frequently used for imaging lipid dynamics in living cells. We report a high‐power picosecond fiber‐based laser and its application for optical parametric oscillator (OPO) pumping and CARS microscopy. This fiber‐based laser has been carefully characterized. It produces 5 ps pulses with 0.8 nm spectral width at a 1,030 nm wavelength with more than 10 W of average power at 80 MHz repetition rate; these spectral and temporal properties can be slightly modified. We then study the influence of these modifications on the spectral and temporal properties of the OPO. We find that the OPO system generates a weakly spectrally chirped signal beam constituted of 3 ps pulses with 0.4 nm spectral width tunable from 790 to 930 nm optimal for CARS imaging. The frequency doubling unconverted part is composed of 7–8 ps pulses with 0.75 nm spectral width compatible with CARS imaging. We also study the influence of the fiber laser properties on the CARS signal generated by distilled water. In agreement with theory, we find that shorter temporal pulses allow higher peak powers and thus higher CARS signal, if the spectral widths are less than 10 cm−1. We demonstrate that this source is suitable for performing CARS imaging of living cells during several hours without photodamages. We finally demonstrate CARS imaging on more complex aquatic organisms called copepods (micro‐crustaceans), on which we distinguish morphological details and lipid reserves. Microsc. Res. Tech. 77:422–430, 2014. © 2014 Wiley Periodicals, Inc.
Nanophotonic approaches for nanoscale imaging and single‐molecule detection at ultrahigh concentrations
Authors: Mivelle Mathieu , Van Zanten Thomas. S. , Manzo Carlo , Garcia‐Parajo Maria F. 
Published: April 2014

ABSTRACTOver the last decade, we have witnessed an outburst of many different optical techniques aimed at breaking the diffraction limit of light, providing super‐resolution imaging on intact fixed cells. In parallel, single‐molecule detection by means of fluorescence has become a common tool to investigate biological interactions at the molecular level both in vitro and in living cells. Despite these advances, visualization of dynamic events at relevant physiological concentrations at the nanometer scale remains challenging. In this review, we focus on recent advancements in the field of nanophotonics toward nanoimaging and single‐molecule detection at ultrahigh sample concentrations. These approaches rely on the use of metal nanostructures known as optical antennas to localize and manipulate optical fields at the nanometer scale. We highlight examples on how different optical antenna geometries are being implemented for nanoscale imaging of cell membrane components. We also discuss different implementations of self‐standing and two‐dimensional antenna arrays for studying nanoscale dynamics in living cell membranes as well as detection of individual biomolecular interactions in the µM range for sensing applications. Microsc. Res. Tech. 77:537–545, 2014. © 2014 Wiley Periodicals, Inc.
Household Shocks and Coping Strategies in Rural and Peri‐Urban South Africa: Baseline Data from the Size Study in Kwazulu‐Natal, South Africa
Authors: Knight Lucia , Roberts Benjamin J. , Aber J. Lawrence , Richter Linda ,   The SIZE Research Group
Published: April 2014

AbstractThe incidence and impact of a range of household shocks are investigated in a survey of households with children in 24 communities in peri‐urban and rural KwaZulu‐Natal, South Africa. The results highlight the importance of health shocks among households in a high HIV prevalence context. Economic shocks, in particular unexpected price increments for basic necessities, are widely reported and shown to have moderate to severe self‐rated impacts with possible long‐term cumulative, community‐wide effects. Behaviour‐based coping responses were the most common, especially reduced consumption and spending, which has the potential for negative impacts on the health developmental and well‐being of children. Copyright © 2014 John Wiley & Sons, Ltd.
Turbulent kinetic energy in normal and myopathic left ventricles
Authors: Zajac Jakub , Eriksson Jonatan , Dyverfeldt Petter , Bolger Ann F. , Ebbers Tino , Carlhäll Carl‐Johan 
Published: April 2014

PurposeTo assess turbulent kinetic energy (TKE) within the left ventricle (LV) of healthy subjects using novel 4D flow magnetic resonance imaging (MRI) methods and to compare TKE values to those from a limited group of patients with a spectrum of dilated cardiomyopathy (DCM).Materials and Methods4D flow and morphological MRI data were acquired in 11 healthy subjects and 9 patients with different degrees of diastolic dysfunction. TKELV was calculated within the LV at each diastolic timeframe. At peak early (E) and late (A) diastolic filling, the TKELV was compared to transmitral peak velocity, LV diameter, and mitral annular diameter.ResultsIn the majority of subjects, TKELV peaks were observed at E and A. Peak TKELV at E was not different between the groups (P = 0.33), and correlated with mitral annular dimensions (r2 = 0.32, P = 0.01). Peak TKELV at A was higher in DCM patients compared to healthy subjects (3.0 ± 1.8 vs. 1.5 ± 0.8 mJ, P = 0.02), and correlated with LV diameter and transmitral velocity (r2 = 0.36, P = 0.01 and r2 = 0.47, P < 0.01, respectively).ConclusionIn LVs of healthy subjects, TKE values are low. Values are highest during early diastole, and diminish with increasing LV size. In a heterogeneous group of DCM patients, late diastolic TKE values are higher than in healthy subjects. J. Magn. Reson. Imaging 2015;41:1021–1029. © 2014 Wiley Periodicals, Inc.
Numerical modeling and optimization of laser soldering for Micro‐USB electric connector
Authors: Zeng Zhi , Li Xunbo , Wang Rui , Li Miao 
Published: April 2014

SummaryThe laser soldering process was introduced in Micro‐USB electronic packaging in this paper. Numerical modeling and analysis was used for laser process parameter design, because experimental measurements of peak temperature and soldering stress are expensive and often intractable. Accurate knowledge of the residual stress and distortion is a prerequisite for the reliability of the electric connector. The present work proposes a three‐dimensional transient heat transfer model of Micro‐USB package laser soldering process. The calculated thermal cycles and distribution are subsequently used to calculate the distortion and thermal stresses. Meanwhile, the effect of process parameters on residual stress and pin distortion was discussed, and the tensile strength, microstructure, and residual stresses of laser soldering were tested. It can be concluded that the proper laser soldering parameters and power can improve the mechanical property of solder joints on Micro‐USB connector. Copyright © 2014 John Wiley & Sons, Ltd.
Statistical–dynamical downscaling for wind energy potentials: evaluation and applications to decadal hindcasts and climate change projections
Authors: Reyers Mark , Pinto Joaquim G. , Moemken Julia 
Published: April 2014

ABSTRACTA statistical–dynamical downscaling (SDD) approach for the regionalization of wind energy output (Eout) over Europe with special focus on Germany is proposed. SDD uses an extended circulation weather type (CWT) analysis on global daily mean sea level pressure fields with the central point being located over Germany. Seventy‐seven weather classes based on the associated CWT and the intensity of the geostrophic flow are identified. Representatives of these classes are dynamically downscaled with the regional climate model COSMO‐CLM. By using weather class frequencies of different data sets, the simulated representatives are recombined to probability density functions (PDFs) of near‐surface wind speed and finally to Eout of a sample wind turbine for present and future climate. This is performed for reanalysis, decadal hindcasts and long‐term future projections. For evaluation purposes, results of SDD are compared to wind observations and to simulated Eout of purely dynamical downscaling (DD) methods.For the present climate, SDD is able to simulate realistic PDFs of 10‐m wind speed for most stations in Germany. The resulting spatial Eout patterns are similar to DD‐simulated Eout. In terms of decadal hindcasts, results of SDD are similar to DD‐simulated Eout over Germany, Poland, Czech Republic, and Benelux, for which high correlations between annual Eout time series of SDD and DD are detected for selected hindcasts. Lower correlation is found for other European countries. It is demonstrated that SDD can be used to downscale the full ensemble of the Earth System Model of the Max Planck Institute (MPI‐ESM) decadal prediction system.Long‐term climate change projections in Special Report on Emission Scenarios of ECHAM5/MPI‐OM as obtained by SDD agree well to the results of other studies using DD methods, with increasing Eout over northern Europe and a negative trend over southern Europe. Despite some biases, it is concluded that SDD is an adequate tool to assess regional wind energy changes in large model ensembles.
pH‐Sensitive Chitosan‐based Hydrogel Nanoparticles through Miniemulsion Polymerization Mediated by Peroxide Containing Macromonomer
Authors: Solomko Nadiya , Budishevska Olga , Voronov Stanislav , Landfester Katharina , Musyanovych Anna 
Published: April 2014

AbstractNew type of hydrogel nanoparticles (HNp) based on chitosan are synthesized by the free radical graft‐copolymerization reaction of peroxide containing chitosan derivative and 1‐vinyl‐2‐pyrrolidone (VP) in the inverse miniemulsion droplets. Free radicals are formed upon thermal decomposition of the peroxide groups that are attached to the chitosan chain. After introduction of the cross‐linker N,N‐methylenebisacrylamide, more densely cross‐linked HNp with a lower pH‐dependant swelling rate are produced. The release behavior is investigated by fluorescence measurements using HNp loaded with either anionic sulforhodamine 101 or cationic rhodamine 123 fluorescent dye. The obtained results revealed that the crucial points in the release kinetic are the nature of used “payload” molecules and their interaction with the hydrogel matrix. Synthesized HNp are of potential interest for diverse biomedical applications including controlled drug release and diagnostic.
MR microscopy of formalin fixed paraffin embedded histology specimens
Authors: Macura Slobodan , Mishra Prasanna K. , Gamez Jeffrey D. , Pirko Istvan 
Published: April 2014

PurposeArchived formalin‐fixed paraffin‐embedded (FFPE) tissue collections represent a valuable informational resource for numerous studies. However, there is no NMR signal from FFPE specimens at room temperature. To obtain MR images and enable comparison of magnetic resonance microscopy (MRM) and histology studies we propose to image FFPE tissue at elevated temperature.MethodsA FFPE tissue block was imaged at 7 Tesla (T) and 16.4T at 70–80°C using T2‐weighting methods. The only difference from standard MR microscopy (MRM) is elevated temperature at which the embedding medium melts.ResultsUsing FFPE murine brain tissue, we were able to demonstrate the feasibility of tissue MRM from paraffin embedded specimens. Histology images taken from the specimen after MRM demonstrate that keeping the FFPE specimen in paraffin melt at 70–80°C for dozens of hours does not affect subsequent histology analysis.ConclusionMRM of FFPE tissue from paraffin melt opens new avenues for analyzing archived histological specimens (biopsies, post mortem, etc.) and for correlating MR images with histology (optical microscopy). In addition, 3D MRM of FFPE specimens could guide histology in search for appropriate regions of interest and subsequently minimize occurrences of false negatives in tissue analysis. Magn Reson Med 71:1989–1994, 2014. © 2014 Wiley Periodicals, Inc.
Intravenous immunoglobulin maintenance treatment in myasthenia gravis: A randomized, controlled trial sample size simulation
Authors: Eienbröker Christian , Seitz Florian , Spengler Anna , Kurz Heike , Seipelt Maria , Sommer Norbert , Oertel Wolfgang H. , Timmesfeld Nina , Tackenberg Björn 
Published: April 2014

ABSTRACTIntroduction: In cases of exacerbation or crisis, myasthenia gravis (MG) patients can be treated with intravenous immunoglobulin (IVIg), plasmapheresis, or immunoadsorption. However, IVIg efficacy data in maintenance treatment are sparse. Methods: We prospectively observed 16 index patients with chronic and insufficiently controlled MG under standard immunosuppressant therapy and symptomatic treatment. The IVIg treatment response was measured using changes in quantitative myasthenia gravis (QMG) score and surrogates. Based on these results, a sample size calculation for a future randomized, controlled trial (RCT) was simulated. Results: There was an enduring decline in QMG score and other parameters of about 50% under IVIg maintenance treatment. RCT sample size calculation results in 73 or 33 patients per arm to detect at least a 20% vs. 30% clinical difference in QMG score. Conclusion: We recommend using the QMG score as a primary endpoint for an RCT of IVIg maintenance for chronic MG. Muscle Nerve 50: 999–1004, 2014
Extracellular magnesium and calcium reduce myotonia in isolated ClC‐1 chloride channel‐inhibited human muscle
Authors: Skov Martin , De Paoli Frank Vincenzo , Lausten Jesper , Nielsen Ole Baekgaard , Pedersen Thomas Holm 
Published: April 2014

ABSTRACTIntroduction: Experimental myotonia induced in rat muscle by ClC‐1 chloride channel‐inhibited has been shown to be related inversely to extracellular concentrations of Mg2+ and Ca2+ ([Mg2+]o and [Ca2+]o) within physiological ranges. Because this implicates a role for [Mg2+]o and [Ca2+]o in the variability of symptoms among myotonia congenita patients, we searched for similar effects of [Mg2+]o and [Ca2+]o on myotonia in human muscle. Methods: Bundles of muscle fibers were isolated from abdominal rectus in patients undergoing abdominal surgery. Myotonia was induced by ClC‐1 inhibition using 9‐anthracene carboxylic acid (9‐AC) and was assessed from integrals of force induced by 5‐Hz stimulation for 2 seconds. Results: Myotonia disappeared gradually when [Mg2+]o or [Ca2+]o were elevated throughout their physiological ranges. These effects of [Mg2+]o and [Ca2+]o were additive and interchangeable. Conclusions: These findings suggest that variations in symptoms in myotonia congenita patients may arise from physiological variations in serum Mg2+ and Ca2+. Muscle Nerve 51: 65–71, 2015
Mitochondrial myopathy with dystrophic features due to a novel mutation in the MTTM gene
Authors: Peverelli Lorenzo , Gold Carl A. , Naini Ali B. , Tanji Kurenai , Akman H. Orhan , Hirano Michio , Dimauro Salvatore 
Published: April 2014

ABSTRACTIntroduction: A 61‐year‐old woman with a 5‐year history of progressive muscle weakness and atrophy had a muscle biopsy characterized by a combination of dystrophic features (necrotic fibers and endomysial fibrosis) and mitochondrial alterations [ragged‐red, cytochrome c oxidase (COX)‐negative fibers]. Methods: Sequencing of the whole mtDNA, assessment of the mutation load in muscle and accessible nonmuscle tissues, and single fiber polymerase chain reaction. Results: Muscle mitochondrial DNA (mtDNA) sequencing revealed a novel heteroplasmic mutation (m.4403G>A) in the gene (MTTM) that encodes tRNAMet. The mutation was not present in accessible nonmuscle tissues from the patient or 2 asymptomatic sisters. Conclusions: The clinical features and muscle morphology in this patient are very similar to those described in a previous patient with a different mutation, also in MTTM, which suggests that mutations in this gene confer a distinctive “dystrophic” quality. This may be a diagnostic clue in patients with isolated mitochondrial myopathy. Muscle Nerve 50:292–295, 2014
FFT‐based bounds on the permeability of complex microstructures
Authors: Bignonnet F. , Dormieux L. 
Published: April 2014

SUMMARYA numerical scheme for the computation of the permeability of complex microstructures is presented. As a darcean counterpart of the FFT‐based scheme in elasticity, the method is designed to be directly coupled with 3D imaging techniques of porous samples, without meshing or definition of an equivalent pore network. The method relies on the variational principle of Hashin and Shtrikman, which ensures a rigorous upper bound status to the estimated permeabilities and provides an energetically consistent rule for heterogeneous voxels comprising both the solid and fluid phases. Copyright © 2014 John Wiley & Sons, Ltd.
Energy‐work‐based numerical manifold seepage analysis with an efficient scheme to locate the phreatic surface
Authors: Wang Yuan , Hu Mengsu , Zhou Quanlin , Rutqvist Jonny 
Published: April 2014

SUMMARYA major challenge in seepage analysis is to locate the phreatic surface in an unconfined aquifer. The phreatic surface is unknown and assumed as a discontinuity separating the seepage domain into dry and wet parts, thus should be determined iteratively with special schemes. In this study, we systematically developed a new numerical manifold method (NMM) model for unconfined seepage analysis. The NMM is a general numerical method for modeling continuous and discontinuous deformation in a unified mathematical form. The novelty of our NMM model is rooted in the NMM two‐cover‐mesh system: the mathematical covers are fixed and the physical covers are adjusted with iterations to account for the discontinuity feature of the phreatic surface. We developed an energy‐work seepage model, which accommodates flexible approaches for boundary conditions and provides a form consistent with that in mechanical analysis with clarified physical meaning of the potential energy. In the framework of this energy‐work seepage model, we proposed a physical concept model (a pipe model) for constructing the penalty function used in the penalty method to uniformly deal with Dirichlet, Neumann, and material boundaries. The new NMM model was applied to study four example problems of unconfined seepage with varying geometric shape, boundary conditions, and material domains. The comparison of our simulation results to those of existing numerical models for these examples indicates that our NMM model can achieve a high accuracy and faster convergence speed with relatively coarse meshes. This NMM seepage model will be a key component of our future coupled hydro‐mechanical NMM model. Copyright © 2014 John Wiley & Sons, Ltd.
Stochastic framework for partially degradation systems with continuous component degradation‐rate‐interactions
Authors: Bian Linkan , Gebraeel Nagi 
Published: April 2014

AbstractMany conventional models that characterize the reliability of multicomponent systems are developed on the premise that for a given system, the failures of its components are independent. Although this facilitates mathematical tractability, it may constitute a significant departure from what really takes place. In many real‐world applications, system components exhibit various degrees of interdependencies, which present significant challenges in predicting degradation performance and the remaining lifetimes of the individual components as well as the system at large. We focus on modeling the performance of interdependent components of networked systems that exhibit interactive degradation processes. Specifically, we focus on how the performance level of one component affects the degradation rates of other dependent components. This is achieved by using stochastic models to characterize how degradation‐based sensor signals associated with the components evolve over time. We consider “Continuous‐Type” component interactions that occur continuously over time. This type of degradation interaction exists in many applications, in which interdependencies occur on a continuum. We use a system of stochastic differential equations to capture such “Continuous‐Type” interaction. In addition, we utilize a Bayesian approach to update the proposed model using real‐time sensor signals observed in the field and provide more accurate estimation of component residual lifetimes. © 2014 Wiley Periodicals, Inc. Naval Research Logistics 61: 286–303, 2014