bluuebunny/crossref_metadata_2025 huggingface dataset:
Synoptic climatology of warm fronts in Southeastern South America
Authors: Ribeiro Bruno Zanetti , Seluchi Marcelo Enrique , Chou Sin Chan
Published: May 2015

This study shows a synoptic climatology of warm fronts in Southeastern South America (SESA). Data from Climate Forecast System Reanalysis (CFSR) was used to identify warm fronts from 1979 to 2010. The identification method was based on the magnitude of meridional gradient of 850‐hPa equivalent potential temperature (θe) and 850‐hPa wind fields. Composites of the most important atmospheric variables were constructed from 1 day before until 1 day after the formation of the warm front. An average frequency of two warm fronts per month is observed, with higher frequencies in austral winter. Most warm fronts precede the formation of extratropical cyclones over Uruguay and form because of the southward movement of previous cold/stationary fronts. Warm fronts form on average around southern Paraguay, northeastern Argentina and western part of southern Brazil and Uruguay, coupled to the eastern edge of the Chaco Low (CL) and the Northwestern Argentinean Low (NAL) where north/northwesterly flow predominates. An upper‐level wave of wavenumber eight supports warm frontogenesis. Location and intensity of synoptic systems associated with a warm front event differ from winter to summer. Elevated instability is commonly present near warm fronts, and the average warm‐front slope is 1 : 110, agreeing with other studies. Instability indices increase after the warm‐front passage, leading to greater rainfall 1 day after the warm front forms.
Microstructure and corrosion resistance behavior of Cr‐Nb alloyed layer on low carbon steel
Authors: Zhu Y.‐M. , Zhang P.‐Z. , Wei X.‐F. , Wei D.‐B. , Chen X.‐H. , Zhou P.
Published: May 2015

The Cr‐Nb alloyed layer formed on the surface of low carbon steel by double glow plasma surface alloying could improve the corrosion resistance of the substrate. The morphology and microstructure of the layer were investigated by scanning electron microscopy, energy dispersive spectrometer and X‐ray diffraction. The average thickness of the alloyed layer is approximately 18 µm. A uniform and dense Cr‐Nb alloyed layer had been synthesized without any cracks and holes on the surface of low carbon steel. The corrosion behavior of the alloyed layer was evaluated by polarization experiments in 3.5 wt% NaCl solution using a CHI660D type electrochemical workstation. Potentiodynamic polarization and electrochemical impedance spectroscopy were applied to evaluate the corrosion resistance of the alloyed layer. Compared with the substrate, the Cr‐Nb alloyed layer exhibited higher corrosion potential, lower corrosion current density and larger charge transfer resistance. The result presents that Cr‐Nb alloyed layer has significantly modified the corrosion resistance of low carbon steel.
Nanocomposite Foams of Polypropylene and Carbon Nanotubes: Preparation, Characterization, and Evaluation of their Performance as EMI Absorbers
Authors: Tran Minh‐Phuong , Thomassin Jean‐Michel , Alexandre Michaël , Jerome Christine , Huynen Isabelle , Detrembleur Christophe
Published: May 2015

Highly expanded nanocomposite foams of polypropylene and carbon nanotubes (PP/CNT) are formed using supercritical carbon dioxide (scCO2) technology. The foaming parameters (temperature, pressure) are investigated to establish their influence on the morphology of the resulting foams and their impact on the electrical conductivity. As promising electromagnetic‐interference (EMI) absorbers, the EMI shielding performance of the foams is determined, and a preliminary relationship is established between foam morphology and the EMI shielding performance. The best candidates are highly expanded foams with a volume expansion of >25, containing 0.1 vol% CNTs; they are able to absorb more than 90% of the incident radiation between 25 and 40 GHz.

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An inexact shift‐and‐invert Arnoldi algorithm for Toeplitz matrix exponential
Authors: Wu Gang , Feng Ting‐ting , Wei Yimin
Published: May 2015

We revisit the shift‐and‐invert Arnoldi method proposed in [S. Lee, H. Pang, and H. Sun.Shift‐invert Arnoldi approximation to the Toeplitz matrix exponential, SIAM J. Sci. Comput., 32: 774–792, 2010] for numerical approximation to the product of Toeplitz matrix exponential with a vector. In this approach, one has to solve two large‐scale Toeplitz linear systems in advance. However, if the desired accuracy is high, the cost will be prohibitive. Therefore, it is interesting to investigate how to solve the Toeplitz systems inexactly in this method. The contribution of this paper is in three regards. First, we give a new stability analysis on the Gohberg–Semencul formula (GSF) and define the GSF condition number of a Toeplitz matrix. It is shown that when the size of the Toeplitz matrix is large, our result is sharper than the one given in [M. Gutknecht and M. Hochbruck.The stability of inversion formulas for Toeplitz matrices, Linear Algebra Appl., 223/224: 307–324, 1995]. Second, we establish a relation between the error of Toeplitz systems and the residual of Toeplitz matrix exponential. We show that if the GSF condition number of the Toeplitz matrix is medium‐sized, then the Toeplitz systems can be solved in a low accuracy. Third, based on this relationship, we present a practical stopping criterion for relaxing the accuracy of the Toeplitz systems and propose an inexact shift‐and‐invert Arnoldi algorithm for the Toeplitz matrix exponential problem. Numerical experiments illustrate the numerical behavior of the new algorithm and show the effectiveness of our theoretical results. Copyright © 2015 John Wiley & Sons, Ltd.
Non‐isocyanate polyurethanes: synthesis, properties, and applications
Authors: Rokicki Gabriel , Parzuchowski Paweł G. , Mazurek Magdalena
Published: May 2015

Conventional polyurethanes are typically obtained from polyisocyanates, polyols, and chain extenders. The main starting materials—isocyanates used in this process—raise severe health hazard concerns. Therefore, there is a growing demand for environment‐friendly processes and products. This review article summarizes progress that has been made in recent years in the development of alternative methods of polyurethane synthesis. In most of them, carbon dioxide is applied as a sustainable feedstock for polyurethane production directly or indirectly. The resulting non‐isocyanate polyurethanes are characterized by a solvent‐free synthesis, resistance to chemical degradation, 20% more wear resistance than conventional polyurethane, and can be applied on wet substrates and cured under cold conditions. Three general polymer synthetic methods, step‐growth polyaddition, polycondensation, and ring‐opening polymerization, are presented in the review. Much attention is given to the most popular and having potential industrial importance method of obtaining non‐isocyanate polyurethanes, poly(hydroxy‐urethane)s, based upon multicyclic carbonates and aliphatic amines. It is evident from the present review that considerable effort has been made during the last years to develop environmentally friendly methods of obtaining polyurethanes, especially those with the use of carbon dioxide or simple esters of carbonic acid. Copyright © 2015 John Wiley & Sons, Ltd.
Fabrication and conduction mechanism evaluation of polyfluorene polymeric Schottky diode
Authors: Mustafa Maria , Sherin Lubna , Kim Hyung Chan , Lee Yun Woo , Choi Kyung Hyun
Published: May 2015

A thin film of polyflourene polymer was sandwiched between a conductive polymer deposited on silver nanowire and metal electrode to form a multilayer polymer‐based diode device. The electrical properties of fabricated polymeric diode have been studied by current–voltage method. The current–voltage characteristics of the fabricated device exhibited non‐ideal, asymmetrical, and rectifying behavior. Ohmic current conduction mechanism was observed in the device at low voltage. At higher voltage values, the space‐charge‐limited current conduction mechanism was found to be dominated. The values of the Schottky barrier height, ideality factor, and saturation current density were extracted according to the standard thermionic emission model and discussed. The barrier height and ideality factor were calculated as 0.72 eV and 2.53, respectively. Copyright © 2015 John Wiley & Sons, Ltd.
Surface modification of MWCNTs with glucose and their utilization for the production of environmentally friendly nanocomposites using biodegradable poly(amide‐imide) based on N‐trimellitylimido‐S‐valine matrix
Authors: Abdolmaleki Amir , Mallakpour Shadpour , Rostami Maryam
Published: May 2015

In the present investigation, the preparation, characterization, and surface morphology of poly(amide‐imide) (PAI)/multi‐walled carbon nanotubes (MWCNTs) bionanocomposites (BNCs) were the main goals of the study. At first, an optically active PAI based on S‐valine as a biodegradable segment was synthesized. Then, carboxyl‐modified MWCNTs were functionalized with glucose (f‐MWCNT) as a biological active molecule in a green method to achieve a fine dispersion of f‐MWCNT bundles in the PAI matrix. The existence of S‐valine in the PAI matrix and functionalized MWCNT with glucose resulted in a series of potentially biodegradable nanocomposites. The obtained BNCs were characterized by various techniques. Field emission scanning and transmission electron microscopy micrographs of the composites showed a fine dispersion of f‐MWCNTs in the polymer matrix because of hydrogen bonding and π–π stacking interaction between f‐MWCNTs and polymer functional groups and aromatic moieties. Adding f‐MWCNTs into polymer matrix significantly improved the thermal stability of BNCs because of the increased interfacial interaction between the PAI matrix and f‐MWCNTs and also good dispersion of f‐MWCNT in the polymer matrix. Copyright © 2015 John Wiley & Sons, Ltd.
Early insights into the neurobiology of pain in sickle cell disease: A systematic review of the literature
Authors: Brandow Amanda M. , Farley Rebecca A. , Panepinto Julie A.
Published: May 2015

Novel insights into the neurobiology of sickle cell disease (SCD) pain have recently been discovered. We systematically reviewed the literature focusing on original research that examined the biology of pain in SCD and/or addressed assessment or treatment of neuropathic pain in SCD. This review of 15 articles that met inclusion criteria provides epidemiological, basic, and clinical data that support central and/or peripheral nervous system abnormalities likely contribute to sickle cell pain. Continued basic and clinical investigation into pain neurobiology is imperative to translate these discoveries into novel ways to assess and treat neuropathic pain and decrease patient suffering. Pediatr Blood Cancer 2015;62:1501–1511. © 2015 Wiley Periodicals, Inc.
Analysis and simulation of the electrical properties of CNTs/epoxy nanocomposites for high performance composite matrices
Authors: Terenzi A. , Natali M. , Petrucci R. , Rallini M. , Peponi L. , Beaumont M. , Eletskii A. , Knizhnik A. , Potapkin B. , Kenny J.M.
Published: May 2015

Carbon fiber composite laminates have good electrical properties due to the performance of the fibers, but the composite anisotropy induces a quite lower conductivity through the thickness. In fact, in this direction the fiber bundles are separated by insulating epoxy matrix. In this work, CNTs (carbon nanotubes) with different geometries and functionalization have been added to an epoxy resin to improve the electrical performance. The nanofilled matrix has been used to produce carbon fiber (CF) composites for aerospace applications. Multiscale modeling was used to predict some important parameters such as percolation threshold and the model has been successfully verified with experimental results. The results reported show a good improvement of the electrical and mechanical properties both in the matrix and in the composites. In particular, in composites with the nanocomposite matrix, an improvement of one order of magnitude in the electrical conductivity through the laminate thickness has been achieved. POLYM. COMPOS., 38:105–115, 2017. © 2015 Society of Plastics Engineers
Shear properties of three‐dimensional woven composite reinforcements
Authors: Sun Fei , Zhang Yifan , Chen Li , Zhang Meiling , Pan Ning
Published: May 2015

This paper presents a comprehensive experimental study and detailed mechanistic interpretations of the shear deformation of three‐dimensional (3D) reinforcements. Six types of 3D angle interlock glass fiber preforms (3DAP) were fabricated using a range of weave parameters including the fabric density, fabric layer, and yarn linear density. A modified picture frame was developed to ensure a pure shear load during the test. Through a series of comprehensive tests, our results demonstrated that the fabric density played a key role in the mechanical properties of 3DAP and that the reinforcements with low fabric density and yarn linear density were easy to shear. The shear deformation mechanism was analyzed based on the meso‐structure. It is expected that this research will provide preliminary work for building a theoretical model of 3D woven preform. POLYM. COMPOS., 38:244–251, 2017. © 2015 Society of Plastics Engineers
Analysis of the dielectric relaxation and ac conductivity behavior of polyvinyl alcohol‐cadmium selenide nanocomposite films
Authors: Sinha Subhojyoti , Chatterjee Sanat Kumar , Ghosh Jiten , Meikap Ajit Kumar
Published: May 2015

We adopt an analytical approach to study the dielectric relaxation and ac conductivity behavior of the polyvinyl alcohol (PVA) ‐ Cadmium Selenide (CdSe) nanocomposite films in the frequency range 100 Hz ≤ f ≤ 1 MHz and in the temperature range 298 K ≤ T ≤ 420 K. The CdSe nanoparticles are synthesized via a simple wet chemical route and are then impregnated into the polyvinyl alcohol matrix by 0.5 wt%, 1 wt%, and 4 wt%. About 1.7 times increase in effective permittivity (at 100 KHz) for the 4 wt% nanoparticle impregnated sample is observed from the analysis of the dielectric reinforcement function, which is attributed to the occurrence of interfacial polarization. It is found that the Cole‐Cole model with a dc conductivity correction term can well fit the permittivity data. We have found that the dielectric relaxation time increases with increase in nanoinclusion into the matrix but decreases with increase in temperature. However, the space charge carrier conductivity and free charge carrier conductivity increase either with increase in nano inclusions or with increase in temperature. AC conductivity behavior have been analyzed considering the Jonscher power law and Dyre's random free energy barrier model, which reveals lowering of the maximum barrier height and correlated barrier hopping as the prevalent charge transport mechanism for the nanocomposites. Electric modulus study indicates similar conductivity relaxation dynamics for the nanocomposites but the responses deviate appreciably from the simulated ideal Debye responses. POLYM. COMPOS., 38:287–298, 2017. © 2015 Society of Plastics Engineers
A prediction of dislocation‐free CdTe/CdS photovoltaic multilayers via nano‐patterning and composition grading
Authors: Zhou Xiao Wang , Ward Donald K. , Doty F. Patrick , Zimmerman Jonathan A. , Wong Bryan M. , Cruz‐Campa Jose Luis , Nielson Gregory N. , Chavez Jose Juan , Zubia David , McClure John C.
Published: May 2015

Defects in multilayered films have long been a performance‐limiting problem for the semiconductor industry. For instance, CdTe/CdS solar cell efficiencies have had significant improvement in the past 15years or more without addressing the problem of high misfit dislocation densities. Overcoming this stagnation requires a fundamental understanding of interfacial defect formation. Herein, we demonstrate a new first principles‐based CdTe bond‐order approach that enables efficient molecular dynamics to approach the fidelity of density functional theory. Stringent quantum‐mechanical verification and experimental validation tests reveal that our new approach provides an accurate prediction of defects that earlier methods cannot. Using this new capability, we show that misfit dislocations in CdTe/CdS multilayers can be significantly reduced via nano‐patterning and composition grading and more importantly, dislocation‐free multilayers naturally arise when the pattern dimension is reduced below 90nm. Our predictive methods are generally applicable to other materials, highlighting a rational approach towards low‐defect semiconductor films. Copyright © 2015 John Wiley & Sons, Ltd.
Advanced analyses of kinetic stabilities of iggs modified by mutations and glycosylation
Authors: Sedlák Erik , Schaefer Jonas V. , Marek Jozef , Gimeson Peter , Plückthun Andreas
Published: May 2015

The stability of Immunoglobulin G (IgG) affects production, storage and usability, especially in the clinic. The complex thermal and isothermal transitions of IgGs, especially their irreversibilities, pose a challenge to the proper determination of parameters describing their thermodynamic and kinetic stability. Here, we present a reliable mathematical model to study the irreversible thermal denaturations of antibody variants. The model was applied to two unrelated IgGs and their variants with stabilizing mutations as well as corresponding non‐glycosylated forms of IgGs and Fab fragments. Thermal denaturations of IgGs were analyzed with three transitions, one reversible transition corresponding to CH2 domain unfolding followed by two consecutive irreversible transitions corresponding to Fab and CH3 domains, respectively. The parameters obtained allowed us to examine the effects of these mutations on the stabilities of individual domains within the full‐length IgG. We found that the kinetic stability of the individual Fab fragment is significantly lowered within the IgG context, possibly because of intramolecular aggregation upon heating, while the stabilizing mutations have an especially beneficial effect. Thermal denaturations of non‐glycosylated variants of IgG consist of more than three transitions and could not be analyzed by our model. However, isothermal denaturations demonstrated that the lack of glycosylation affects the stability of all and not just of the CH2 domain, suggesting that the partially unfolded domains may interact with each other during unfolding. Investigating thermal denaturation of IgGs according to our model provides a valuable tool for detecting subtle changes in thermodynamic and/or kinetic stabilities of individual domains.
Membrane proteins in their native habitat as seen by solid‐state NMR spectroscopy
Authors: Brown Leonid S. , Ladizhansky Vladimir
Published: May 2015

Membrane proteins play many critical roles in cells, mediating flow of material and information across cell membranes. They have evolved to perform these functions in the environment of a cell membrane, whose physicochemical properties are often different from those of common cell membrane mimetics used for structure determination. As a result, membrane proteins are difficult to study by traditional methods of structural biology, and they are significantly underrepresented in the protein structure databank. Solid‐state Nuclear Magnetic Resonance (SSNMR) has long been considered as an attractive alternative because it allows for studies of membrane proteins in both native‐like membranes composed of synthetic lipids and in cell membranes. Over the past decade, SSNMR has been rapidly developing into a major structural method, and a growing number of membrane protein structures obtained by this technique highlights its potential. Here we discuss membrane protein sample requirements, review recent progress in SSNMR methodologies, and describe recent advances in characterizing membrane proteins in the environment of a cellular membrane.
A comparison of the folding characteristics of free and ribosome‐tethered polypeptide chains using limited proteolysis and mass spectrometry
Authors: Rajabi Khadijeh , Reuther Julia , Deuerling Elke , Radford Sheena E. , Ashcroft Alison E.
Published: May 2015

The kinetics and thermodynamics of protein folding are commonly studied in vitro by denaturing/renaturing intact protein sequences. How these folding mechanisms relate to de novo folding that occurs as the nascent polypeptide emerges from the ribosome is much less well understood. Here, we have employed limited proteolysis followed by mass spectrometry analyses to compare directly free and ribosome‐tethered polypeptide chains of the Src‐homology 3 (SH3) domain and its unfolded variant, SH3‐m10. The disordered variant was found to undergo faster proteolysis than SH3. Furthermore, the trypsin cleavage patterns observed show minor, but significant, differences for the free and ribosome‐bound nascent chains, with significantly fewer tryptic peptides detected in the presence of ribosome. The results highlight the utility of limited proteolysis coupled with mass spectrometry for the structural analysis of these complex systems, and pave the way for detailed future analyses by combining this technique with chemical labeling methods (for example, hydrogen‐deuterium exchange, photochemical oxidation) to analyze protein folding in real time, including in the presence of additional ribosome‐associated factors.
The role of conformational selection in the molecular recognition of the wild type and mutants XPA67‐80 peptides by ERCC1
Authors: Fadda Elisa
Published: May 2015

Molecular recognition is a fundamental step in the coordination of biomolecular pathways. Understanding how recognition and binding occur between highly flexible protein domains is a complex task. The conformational selection theory provides an elegant rationalization of the recognition mechanism, especially valid in cases when unstructured protein regions are involved. The recognition of a poorly structured peptide, namely XPA67‐80, by its target receptor ERCC1, falls in this challenging study category. The microsecond molecular dynamics (MD) simulations, discussed in this work, show that the conformational propensity of the wild type XPA67‐80 peptide in solution supports conformational selection as the key mechanism driving its molecular recognition by ERCC1. Moreover, all the mutations of the XPA67‐80 peptide studied here cause a significant increase of its conformational disorder, relative to the wild type. Comparison to experimental data suggests that the loss of the recognized structural motifs at the microscopic time scale can contribute to the critical decrease in binding observed for one of the mutants, further substantiating the key role of conformational selection in recognition. Ultimately, because of the high sequence identity and analogy in binding, it is conceivable that the conclusions of this study on the XPA67‐80 peptide also apply to the ERCC1‐binding domain of the XPA protein. Proteins 2015; 83:1341–1351. © 2015 Wiley Periodicals, Inc.
Rosetta comparative modeling for library design: Engineering alternative inducer specificity in a transcription factor
Authors: Jha Ramesh K. , Chakraborti Subhendu , Kern Theresa L. , Fox David T. , Strauss Charlie E. M.
Published: May 2015

Structure‐based rational mutagenesis for engineering protein functionality has been limited by the scarcity and difficulty of obtaining crystal structures of desired proteins. On the other hand, when high‐throughput selection is possible, directed evolution‐based approaches for gaining protein functionalities have been random and fortuitous with limited rationalization. We combine comparative modeling of dimer structures, ab initio loop reconstruction, and ligand docking to select positions for mutagenesis to create a library focused on the ligand‐contacting residues. The rationally reduced library requirement enabled conservative control of the substitutions by oligonucleotide synthesis and bounding its size within practical transformation efficiencies (∼107 variants). This rational approach was successfully applied on an inducer‐binding domain of an Acinetobacter transcription factor (TF), pobR, which shows high specificity for natural effector molecule, 4‐hydroxy benzoate (4HB), but no native response to 3,4‐dihydroxy benzoate (34DHB). Selection for mutants with high transcriptional induction by 34DHB was carried out at the single‐cell level under flow cytometry (via green fluorescent protein expression under the control of pobR promoter). Critically, this selection protocol allows both selection for induction and rejection of constitutively active mutants. In addition to gain‐of‐function for 34DHB induction, the selected mutants also showed enhanced sensitivity and response for 4HB (native inducer) while no sensitivity was observed for a non‐targeted but chemically similar molecule, 2‐hydroxy benzoate (2HB). This is unique application of the Rosetta modeling protocols for library design to engineer a TF. Our approach extends applicability of the Rosetta redesign protocol into regimes without a priori precision structural information. Proteins 2015; 83:1327–1340. © 2015 Wiley Periodicals, Inc.
Structural diversity of the epigenetics pocketome
Authors: Cabaye Alexandre , Nguyen Kong T , Liu Lihua , Pande Vineet , Schapira Matthieu
Published: May 2015

Protein families involved in chromatin‐templated events are emerging as novel target classes in oncology and other disease areas. The ability to discover selective inhibitors against chromatin factors depends on the presence of structural features that are unique to the targeted sites. To evaluate challenges and opportunities toward the development of selective inhibitors, we calculated all pair wise structural distances between 575 structures from the protein databank representing 163 unique binding pockets found in protein domains that write, read or erase post‐translational modifications on histones, DNA, and RNA. We find that the structural similarity of binding sites does not always follow the sequence similarity of protein domains. Our analysis reveals increased risks of activity across target‐class for compounds competing with the cofactor of protein arginine methyltransferases, lysine acetyltransferases, and sirtuins, while exploiting the conformational plasticity of a protein target is a path toward selective inhibition. The structural diversity landscape of the epigenetics pocketome can be explored via an open‐access graphic user interface at thesgc.org/epigenetics_pocketome. Proteins 2015; 83:1316–1326. © 2015 Wiley Periodicals, Inc.
Analysis of main failure pattern using discrete Fourier transform on metal‐epoxy‐based adherent‐laminates
Authors: Niederwimmer Karin , Kieberger Benjamin , Hassel Achim Walter
Published: May 2015

Sandwich‐structured materials are widely used in science, industry and consumer products and therefore have to fulfil several parameters of the designed application, but in particular mechanical stability. This article focuses on mechanical testing of composite sandwich‐structured laminates, consisting of metal and epoxy‐based adherent. As peel forces denote enormous strains for adhesives, floating roller method was used to determine the mechanical stability of the laminates. Besides the peel resistance, the main failure pattern is also of interest as it has an influence on the long‐term stability of the laminates. Therefore, the curves of mechanical testing were investigated using discrete Fourier transform (DFT) to give an indication of the predominating failure mechanism. The samples themselves were analysed using light microscopy to validate the results of the DFT.
Development and characterization of novel 8‐plex DiLeu isobaric labels for quantitative proteomics and peptidomics
Authors: Frost Dustin C. , Greer Tyler , Xiang Feng , Liang Zhidan , Li Lingjun
Published: May 2015

Rationale

Relative quantification of proteins via their enzymatically digested peptide products determines disease biomarker candidate lists in discovery studies. Isobaric label‐based strategies using TMT and iTRAQ allow for up to 10 samples to be multiplexed in one experiment, but their expense limits their use. The demand for cost‐effective tagging reagents capable of multiplexing many samples led us to develop an 8‐plex version of our isobaric labeling reagent, DiLeu.

Methods

The original 4‐plex DiLeu reagent was extended to an 8‐plex set by coupling isotopic variants of dimethylated leucine to an alanine balance group designed to offset the increasing mass of the label's reporter group. Tryptic peptides from a single protein digest, a protein mixture digest, and Saccharomyces cerevisiae lysate digest were labeled with 8‐plex DiLeu and analyzed via nanospray liquid chromatography/tandem mass spectrometry (nanoLC/MS2) on a Q‐Exactive Orbitrap mass spectrometer. Characteristics of 8‐plex DiLeu‐labeled peptides, including quantitative accuracy and fragmentation, were examined.

Results

An 8‐plex set of DiLeu reagents with 1 Da spaced reporters was synthesized at a yield of 36%. The average cost to label eight 100 µg peptide samples was calculated to be approximately $15. Normalized collision energy tests on the Q‐Exactive revealed that a higher‐energy collisional dissociation value of 27 generated the optimum number of high‐quality spectral matches. Relative quantification of DiLeu‐labeled peptides yielded normalized median ratios accurate to within 12% of their expected values.

Conclusions

Cost‐effective 8‐plex DiLeu reagents can be synthesized and applied to relative peptide and protein quantification. These labels increase the multiplexing capacity of our previous 4‐plex implementation without requiring high‐resolution instrumentation to resolve reporter ion signals. Copyright © 2015 John Wiley & Sons, Ltd.
Application of super‐resolution reconstruction of sparse representation in mass spectrometry imaging
Authors: Tang Fei , Bi Ying , He Jiuming , Li Tiegang , Abliz Zeper , Wang Xiaohao
Published: May 2015

Rationale

Mass Spectrometry Imaging (MSI) is useful for analyzing biological samples directly, as a spatially resolved, label‐free technique. Here we present a method for super‐resolution reconstruction of sparse representation to improve resolution of MSI data.

Methods

Air Flow‐Assisted Ionization Mass Spectrometry Imaging (AFAI‐MSI) was used to acquire MSI data from ink samples, thyroid tumour samples, rat renal biopsies, and rat brain biopsy samples. Super‐resolution reconstruction of sparse representation was adopted for the collected MSI data.

Results

After comparison of the reconstructed high‐resolution image and the original high‐resolution image, it is found that super‐resolution reconstruction image is closer to the original high‐resolution image than the image obtained with the interpolation method, and the highest Peak Signal‐to‐Noise Ratio (PSNR) difference value is over 1.4dB. Therefore, the application of the super‐resolution reconstruction technique, based on sparse representation MSI, is feasible and effective.

Conclusions

The method proposed here not only improves the resolution of MSI in post‐data processing, but also acquires fewer sampling points at the same resolution, thereby greatly reducing the sampling time, with great application value for large‐volume sample MSI, high‐resolution MSI, etc. Copyright © 2015 John Wiley & Sons, Ltd.
Matrix‐assisted laser desorption/ionisation quadrupole ion trap time‐of‐flight mass spectrometry of novel shape‐persistent macrocycles
Authors: Amato Filippo , Phulwale Bhimrao Vaijnath , Mazal Ctibor , Havel Josef
Published: May 2015

Rationale

Shape‐persistent macrocycles (SPMs) represent innovative molecular building blocks for the development of highly organised supramolecular architectures with application in nanotechnology, chemistry, catalysis and optoelectronics. Systematic mass spectrometric characterisation of SPMs and their collision‐activated decay is not available to date.

Methods

Characterisation of alkoxy‐decorated SPMs was performed by matrix‐assisted laser desorption/ionisation quadrupole ion trap time‐of‐flight mass spectrometry (MALDI‐QIT‐TOFMS) and collision‐induced dissociation (CID).

Results

Laser excitation of SPMs leads to the formation of stable cation radicals which show characteristic fragmentation patterns. All the product ions formed were identified. Photoelectrons generated during the MALDI process and full‐ring conjugation were found to be fundamental for the formation of molecular cation radicals and their stabilisation, respectively. Formation of supramolecular aggregates of SPMs by π‐π stacking was proven. SPMs are suitable motifs for the preparation of novel fullerene‐based donor‐acceptor systems.

Conclusions

Alkoxy‐decorated SPMs represent promising electron‐donating building blocks that can be exploited in electronics and optoelectronics for the development of robust and highly efficient laser‐activated supramolecular switches. Copyright © 2015 John Wiley & Sons, Ltd.
Insights into the binding sites of sulforaphane on insulin studied by electrospray ionization mass spectrometry
Authors: Nagaveni V. , Prabhakar S.
Published: May 2015

Rationale

Sulforaphane (SFN) is a natural isothiocyanate, known to reduce the risk of cancer and also aortic damage and diabetic cardiomyopathy induced by type 2 diabetes, etc. A more detailed knowledge on the direct interaction of SFN with insulin and its binding sites is necessary for better understanding the role of SFN on diabetes.

Methods

Liquid chromatography/electrospray ionization mass spectrometry (LC/ESI‐MS) and in‐source fragmentation experiments were performed on a Thermo Exactive orbitrap mass spectrometer. The solution of insulin and SFN was incubated and analyzed by mass spectrometry. Isotopic distribution pattern, accurate mass values and theoretical product ions were used to analyze the mass spectrometry data. The nature of binding of SFN and its binding sites with insulin were evaluated by LC/MS data.

Results

ESI‐MS analysis of the incubated solution of insulin and SFN showed 1:1 and 1:2 complexes of [Insulin‐SFN]. LC/MS analysis revealed that the [Insulin+SFN] complexes were due to covalent binding of SFN at two different sites. The in‐source fragmentation experiments revealed that the SFN is binding to the NH2 groups of N‐terminal amino acids of A and B chains of insulin. Further study of SFN with insulin reduced with dithiothreitol (DTT) showed exclusive modification of cysteines with SFN.

Conclusions

The interaction of SFN was studied with insulin using ESI‐MS. SFN is found to bind covalently with the free NH2 group of the N‐terminal of the A and B chains of insulin. However, when insulin is reduced SFN preferably binds to SH groups of cysteines. Hence, the present study helps in the understanding of the binding sites of SFN on insulin. Copyright © 2015 John Wiley & Sons, Ltd.
Design and performance of an all‐Internet Protocol mobile satellite system
Authors: Ravishankar Channasandra , Noerpel Anthony , Jong James J. , Zakaria Gaguk , BenAmmar Nassir , Arur Deepak , Morris Adrian , Leon Giadira , Huang Xiaoling , Ramchandran Harish , Xu Erik , Vasavada Yash , Barnett Charles
Published: May 2015

Third and Fourth Generation (3G and 4G) terrestrial systems provide higher speed Internet Protocol multimedia services to end‐users with differentiated QoS across applications. To facilitate this, terrestrial architectures are moving towards an end‐to‐end all‐IP architecture that unifies all services, including Voice over IP bearer. In parallel, Mobile Satellite Systems (MSS) are being designed to complement and/or co‐exist with terrestrial coverage depending on spectrum sharing rules and operator choice. The challenge for MSS designers is to address the different physical layer characteristics while maintaining interoperability and compatibility with terrestrial services and reuse 3G Partnership Project core networks.

To this end, MSS have been developed that mirror terrestrial Second Generation, 2.5G and 3G systems and are already operational in different parts of the world using different orbital constellations from low Earth orbits to geostationary orbits and both proprietary and standardized air interfaces. This paper describes architectures and methods for mobile satellite systems to achieve services similar to 3G and Fourth Generation terrestrial systems, focusing on the European Telecommunications Standards Institute Geostationary‐Mobile Radio GMR‐1 3G satellite air interface standard. Copyright © 2015 John Wiley & Sons, Ltd.
The influence of anti‐wear additive ZDDP on doped and undoped diamond‐like carbon coatings
Authors: Austin Louise , Liskiewicz Tomasz , Kolev Ivan , Zhao Hongyuan , Neville Anne
Published: May 2015

Diamond‐like carbon (DLC) coatings are recognised as a promising way to reduce friction and improve wear performance of automotive engine components. DLC coatings provide new possibilities in the improvement of the tribological performance of automotive components beyond what can be achieved with lubricant design alone. Lubricants are currently designed for metallic surfaces, the tribology of which is well defined and documented. DLC does not share this depth of tribological knowledge; thus, its practical implementation is stymied. In this work, three DLC coatings are tested: an amorphous hydrogenated DLC, a silicone‐doped amorphous hydrogenated DLC and a tungsten‐doped amorphous hydrogenated DLC. The three coatings are tested tribologically on a pin‐on‐reciprocating plate tribometer against a cast iron pin in a group III base oil, and a fully formulated oil that consists of a group III base oil and contains ZDDP, at 100 °C for 6 h and for 20 h in order to determine whether a phosphor‐based tribofilm is formed at the contact. The formation of a tribofilm is characterised using atomic force microscopy and X‐ray photoelectron spectroscopy techniques. The main findings of this study are the formation of a transfer film at the undoped, amorphous hydrogenated DLC surface, and also the tungsten amorphous hydrogenated DLC having a significant wear removal during the testing. The three coatings were found to have differing levels of wear, with the tungsten‐doped DLC showing the highest, the silicon‐doped DLC showing some coating removal and the amorphous hydrogenated DLC showing only minimal signs of wear. Copyright © 2015 John Wiley & Sons, Ltd.
Influence of process parameters and added starches on resistant starch content and sensory properties of maize extrudates
Authors: Šárka Evžen , Smrčková Petra , Chena Aldao David Antonio , Sağlamtaş Meltem , Koláček Jaroslav , Pour Vladimír
Published: May 2015

Maize grits with or without starchy additives (native wheat starch, distarch phosphates, soluble fiber) were extruded through a single‐screw laboratory extruder Brabender KE 19/25 with a controlled barrel temperature in three zones and in a head, die diameter 4 mm, comprising a compression ratio of the screw of 2:1. The purpose was to influence resistant starch (RS) content together with improving/saving key physicochemical properties by controlling extrusion cooking variables (water addition into feed of 5–20%, screw speed 80–120 rpm, temperature, mass fraction of the additive in the dry premix 0–50%). The influences of most starchy additives were negligible. Pre‐gelatinized cross‐linked starch and soluble fiber nutriose influenced significantly the process pressure, where a low value exhibited high values RS. Based on the data of 48 trials, 7 mathematical optimization models were computed. High RS content worsened the expansion ratio. To obtain a RS content of 1%, it was necessary to decrease expansion ratio to 1.7 where the breaking strength was acceptable. The result of minimizing resistant starch content created an expansion ratio from 2.6 to 2.7, a breaking strength ≤1 N/mm2 and a RS content (maximum) of 0.2%.
Comparison of two Kampo medicines in a diet‐induced mouse obesity model
Authors: Gao Fengying , Yokoyama Satoru , Fujimoto Makoto , Tsuneyama Koichi , Saiki Ikuo , Shimada Yutaka , Hayakawa Yoshihiro
Published: May 2015

Aim

Boiogito (BOT) and bofutsushosan (BTS) are major traditional Kampo medicines that have been widely used for obesity in Japan. In this study, we used a high‐fat diet‐induced obesity (DIO) mouse model to conduct a comparative study of the therapeutic efficacy of BOT and BTS in obesity.

Methods

C57BL/6J mice were fed a high‐fat diet for 10 weeks in order to generate the DIO mouse model and were treated with Kampo medicines for 12 weeks. Bodyweight and food intake were monitored weekly and blood and tissue samples were collected.

Results

While neither BOT nor BTS had any significant impact on body composition in the DIO mice, serum leptin was significantly decreased in both BOT‐ and BTS‐treated DIO mice. In contrast to blood leptin, BOT suppressed, whereas BTS increased, blood insulin in the DIO mice. In addition to these serum obesity markers, BOT reduced liver triglyceride and total cholesterol content, as well as steatosis. Importantly, the mRNA expression of molecules associated with lipid metabolism was reduced in the DIO mice treated with BOT, whereas BTS instead reduced liver mRNA expression of tumor necrosis factor‐α. Both BOT and BTS inhibited adipocyte maturation, as seen in the inhibition of adipocyte enlargement in the white adipose tissue of DIO mice.

Conclusion

BOT and BTS have different therapeutic benefits in obesity due to their modulation of lipid metabolism and of anti‐inflammatory effects, respectively.
Uterine artery pulsatility index at 30–34 weeks' gestation in the prediction of adverse perinatal outcome
Authors: Valiño N. , Giunta G. , Gallo D. M. , Akolekar R. , Nicolaides K. H.
Published: May 2015

Objective

To investigate the potential value of uterine artery (UtA) Doppler at 30–34 weeks' gestation in the prediction of adverse perinatal outcome.

Methods

This was a screening study in 30 780 singleton pregnancies at 30–34 weeks. UtA pulsatility index (UtA‐PI) was measured and the values were converted to multiples of the median (MoM) after adjustment for variables relating to maternal characteristics and medical history that affect the measurements. Multivariable logistic regression analysis was used to determine if measuring UtA‐PI improved the prediction of adverse perinatal outcome provided by screening with maternal characteristics, medical history and obstetric factors. The detection rate (DR) and false‐positive rate (FPR) of screening by UtA‐PI were estimated for stillbirth, Cesarean section for fetal distress, umbilical arterial cord blood pH ≤ 7.0 or umbilical venous cord blood pH ≤ 7.1 and 5‐min Apgar score < 7.

Results

The incidence of adverse perinatal outcome was higher in small‐for‐gestational‐age (SGA) fetuses than in non‐SGA fetuses, but the majority of cases with each adverse outcome were in the non‐SGA group, including about 70% of stillbirths and more than 80% with Cesarean section for fetal distress, low cord blood pH and low Apgar score. The performance of UtA‐PI > 95th percentile in screening for each adverse outcome was poor with DR of 6–16% and a FPR of 5–6%. The DR of adverse outcome when screening by high UtA‐PI was greater in pregnancies complicated by SGA than in non‐SGA pregnancies; 24% vs 13% for stillbirth, 15% vs 5% for Cesarean section for fetal distress, 30% vs 9% for low cord blood pH and 20% vs 3% for low 5‐min Apgar score, respectively.

Conclusion

High UtA‐PI at 30–34 weeks' gestation may be useful in the prediction of adverse perinatal outcome in pregnancies with a SGA fetus, however, in the absence of SGA, UtA‐PI is a poor predictor of adverse outcome. Copyright © 2015 ISUOG. Published by John Wiley & Sons Ltd.
Amino Acid Profiles of 44 Soybean Lines and ACE‐I Inhibitory Activities of Peptide Fractions from Selected Lines
Authors: Rayaprolu Srinivas , Hettiarachchy Navam , Horax Ronny , Satchithanandam Eswaranandam , Chen Pengyin , Mauromoustakos Andy
Published: May 2015

Soybeans are cultivated in the United States chiefly for cooking oil, while the residue after oil extraction (soybean meal) is mostly used in animal feed formulations. High protein content in the defatted soybean meals led to the extraction of pure protein and its application in food products. We selected 44 soybean lines to determine their moisture and protein contents, and their amino acid composition was investigated. Soybean lines with high protein content, one high yielding (R95‐1705), and two high oleic acid (N98‐4445A, S03‐543CR), were selected for protein isolate preparation, hydrolysis using alcalase and gastro‐intestinal (GI) resistance. Furthermore, the GI resistant hydrolysates were fractionated and tested for angiotensin‐I‐converting enzyme (ACE‐I) inhibition activity. The amino acid analysis showed high methionine in the high protein and fatty acid lines (R05‐4494 and R05‐5491), and high cysteine content in one of the high oleic acid soybean line CRR05‐188 in comparison to the check lines (UA‐4805 and 5601‐T). The protein isolate with the highest purity (90–93 %) was derived from the selected lines N98‐4445A and S03‐543CR, and hydrolyzed using alcalase enzyme. The protein hydrolysates (500 µg/mL) showed inhibition of the ACE‐I by 49 %. The results from this study will promote the use of high oleic acid soybeans as a source of protein and peptides with functional activities.
A Systematic Review of the Burden of Pancreatic Cancer in Europe: Real-World Impact on Survival, Quality of Life and Costs
Authors: Carrato A. , Falcone A. , Ducreux M. , Valle J. W. , Parnaby A. , Djazouli K. , Alnwick-Allu K. , Hutchings A. , Palaska C. , Parthenaki I.
Published: May 2015

Purpose

The purpose of this study was to assess the overall burden of pancreatic cancer in Europe, with a focus on survival time in a real-world setting, and the overall healthy life lost to the disease.

Methods

Real-world data were retrieved from peer-reviewed, observational studies identified by an electronic search. We performed two de novo analyses: a proportional shortfall analysis to quantify the proportion of healthy life lost to pancreatic cancer and an estimation of the aggregate life-years lost annually in Europe.

Results

Ninety-one studies were included. The median, age-standardised incidence of pancreatic cancer per 100,000 was 7.6 in men and 4.9 in women. Overall median survival from diagnosis was 4.6 months; median survival was 2.8–5.7 months in patients with metastatic disease. The proportional shortfall analysis showed that pancreatic cancer results in a 98 % loss of healthy life, with a life expectancy at diagnosis of 4.6 months compared to 15.1 years for an age-matched healthy population. Annually, 610,000–915,000 quality-adjusted life-years (QALYs) are lost to pancreatic cancer in Europe. Patients had significantly lower scores on validated health-related quality of life instruments versus population norms.

Conclusions

To the best of our knowledge, this is the first study to systematically review real-world overall survival and patient outcomes of pancreatic cancer patients in Europe outside the context of clinical trials. Our findings confirm the poor prognosis and short survival reported by national studies. Pancreatic cancer is a substantial burden in Europe, with nearly a million aggregate life-years lost annually and almost complete loss of healthy life in affected individuals.