bluuebunny/crossref_metadata_2025_split huggingface dataset:
Quantum efficiencies in finite disordered networks connected by many‐body interactions
Authors: Ortega Adrian , Vyas Manan , Benet Luis 
Published: June 2015

The quantum efficiency in the transfer of an initial excitation in disordered finite networks, modeled by the k‐body embedded Gaussian ensembles of random matrices, is studied for bosons and fermions. The influence of the presence or absence of time‐reversal symmetry and centrosymmetry/centrohermiticity are addressed. For bosons and fermions, the best efficiencies of the realizations of the ensemble are dramatically enhanced when centrosymmetry (centrohermiticity) is imposed. For few bosons distributed in two single‐particle levels this permits perfect state transfer for almost all realizations when one‐particle interactions are considered. For fermionic systems the enhancement is found to be maximal for cases when all but one single particle levels are occupied.
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Bottom‐Up Construction of Mesoporous Nanotubes from 78‐Component Self‐Assembled Nanobarrels
Authors: Zhang Guang‐Lu , Zhou Li‐Peng , Yuan Da‐Qiang , Sun Qing‐Fu 
Published: June 2015

AbstractSegmental and continuous hexagonal‐packed mesoporous metal–organic nanotubes (MMONTs) with outside diameters of up to 4.5 nm and channel sizes of 2.4 nm were hierarchically constructed by a rational multicomponent self‐assembly process involving starting from [L2Pd2(NO3)2] (L=o‐phenanthroline or 2,2′‐bipyridine) and 4‐pyridinyl‐3‐pyrazole. An unprecedented crystallization‐driven cross‐linking between discrete nanobarrel building units by spontaneous loss of the capping ligands to form infinite nanotubes was observed. Such a barrel‐to‐tube transformation provides new possibilities for the fabrication of MMONTs using the solution bottom‐up approach.
Preparation and characterization of mPEG‐g‐α‐zein biohybrid micelles as a nano‐carrier
Authors: Song Rongguang , Zhou Yihan , Li Yanchun , Yang Zechuan , Li Fan , Huang Qingrong , Shi Tongfei , Zhang Guo 
Published: June 2015

ABSTRACTA new kind of block copolymer micelles methoxy polyethylene glycol (mPEG) grafted α‐zein protein (mPEG‐g‐α‐zein) was synthesized. The chemical composition of mPEG‐g‐α‐zein was identified with the help of FT‐IR and 1H‐NMR. The biohybrid polymer can self‐assemble into spherical core–shell nanoparticles in aqueous solution. Scanning electron microscopy (SEM) and atomic force microscopy (AFM) were used to investigate the self‐assembled morphology of mPEG‐g‐α‐zein. Dynamic light scattering (DLS) results showed that the particle size of mPEG‐g‐α‐zein was about 90 nm. Moreover, the nanoparticles had a very low critical micelle concentration value with only 0.02 mg/mL. Then, the anticancer drug curcumin (CUR) was encapsulated into the biohybrid polymer micelles. The in vitro drug release profile showed a zero‐order release of CUR up to 12 h at 37°C. Cell viability studies revealed that the mPEG‐g‐α‐zein polymer exhibited low cytotoxicity for HepG2 cells (human hepatoma cells). Consequently, the mPEG‐g‐α‐zein micelles can be used as a potential nano‐carrier to encapsulate hydrophobic drugs and nutrients. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42555.
Qualitative analysis of chemical constituents in traditional Chinese medicine analogous formula cheng‐Qi decoctions by liquid chromatography–mass spectrometry
Authors: Wen Xuexun , Luo Kedi , Xiao Shun , Ai Ni , Wang Shufang , Fan Xiaohui 
Published: June 2015

AbstractCheng‐Qi decoctions (CQs), a group of analogous formulas, are well‐known traditional Chinese preparations used as purgative remedies to treat ‘internal heat’‐induced symptoms, which manifest as a bloated and painful abdomen, hard stools, fever and other clinical observations. In this study, HPLC‐ESI‐MS/MS and UPLC‐TOF‐MS were employed for separation and structural identification of constituents in CQs. As a result, a total of 90 compounds, including seven anthraquinones, 39 flavones, 21 glycosides, 11 stilbene glycosides, six organic acids, five coumarins and one lignans, were detected and tentatively identified in CQs extracts. The characterization results shed some light on the scientific foundation for clinical application of the CQ analogous formulas. Our results also indicate that the HPLC‐MS method is useful for the systemic identification of major constituents in traditional Chinese medicine formulas. Copyright © 2015 John Wiley & Sons, Ltd.
“Hummingbird” Behaviour of N‐Heterocyclic Carbenes Stabilises Out‐of‐Plane Bonding of AuCl and CuCl Units
Authors: Teci Matthieu , Brenner Eric , Matt Dominique , Gourlaouen Christophe , Toupet Loic 
Published: June 2015

AbstractAn N‐heterocyclic carbene substituted by two expanded 9‐ethyl‐9‐fluorenyl groups was shown to bind an AuCl unit in an unusual manner, namely with the AuX rod sitting out of the plane defined by the heterocyclic carbene unit. As shown by X‐ray studies and DFT calculations, the observed large pitch angle (21°) arises from an easy displacement of the gold(I) atom away from the carbene lone‐pair axis, combined with the stabilisation provided by weak CH⋅⋅⋅Au interactions involving aliphatic and aromatic H atoms of the NHC wingtips. Weak, intermolecular Cl⋅⋅⋅H bonds are likely to cooperate with the H⋅⋅⋅Au interactions to stabilise the out‐of‐plane conformation. A general belief until now was that tilt angles in NHC complexes arise mainly from steric effects within the first coordination sphere.
Influence of Fluorination on the Conformational Properties and Hydrogen‐Bond Acidity of Benzyl Alcohol Derivatives
Authors: Bogdan Elena , Compain Guillaume , Mtashobya Lewis , Le Questel Jean‐Yves , Besseau François , Galland Nicolas , Linclau Bruno , Graton Jérôme 
Published: June 2015

AbstractThe effect of fluorination on the conformational and hydrogen‐bond (HB)‐donating properties of a series of benzyl alcohols has been investigated experimentally by IR spectroscopy and theoretically with quantum chemical methods (ab initio (MP2) and DFT (MPWB1K)). It was found that o‐fluorination generally resulted in an increase in the HB acidity of the hydroxyl group, whereas a decrease was observed upon o,o′‐difluorination. Computational analysis showed that the conformational landscapes of the title compounds are strongly influenced by the presence of o‐fluorine atoms. Intramolecular interaction descriptors based on AIM, NCI and NBO analyses reveal that, in addition to an intramolecular OH⋅⋅⋅F interaction, secondary CH⋅⋅⋅F and/or CH⋅⋅⋅O interactions also occur, contributing to the stabilisation of the various conformations, and influencing the overall HB properties of the alcohol group. The benzyl alcohol HB‐donating capacity trends are properly described by an electrostatic potential based descriptor calculated at the MPWB1K/6‐31+G(d,p) level of theory, provided solvation effects are taken into account for these flexible HB donors.
1,2,4‐Triazole Links and N‐Azo Bridges Yield Energetic Compounds
Authors: Tang Yongxing , Gao Haixiang , Parrish Damon A. , Shreeve Jean'ne M. 
Published: June 2015

AbstractTriazole links and polynitropyrazole rings give rise to compounds with energetic properties. These materials were fully characterized by NMR and infrared spectroscopy, elemental analysis, and differential scanning calorimetry (DSC). In addition, the structures of compounds 5 and 8 were confirmed by single‐crystal X‐ray diffraction analysis. Detonation properties, calculated from heats of formation and experimental densities, thermal stabilities, and impact and friction sensitivities support the potential use of these materials for explosive applications.
Palladium‐Catalyzed C(sp3)H Arylation of N‐Boc Benzylalkylamines via a Deprotonative Cross‐Coupling Process
Authors: Hussain Nusrah , Kim Byeong‐Seon , Walsh Patrick J. 
Published: June 2015

AbstractDiarylmethylamines are key intermediates and products in the pharmaceutical industry. Herein we disclose a novel method toward the synthesis of these important compounds via CH functionalization. Presented is a reversible deprotonation of N‐Boc benzylalkylamines at the benzylic CH with in situ arylation by a NiXantPhos‐based palladium catalyst (50–93 % yield, 29 examples). The method is also successful with N‐Boc‐tetrahydroisoquinolines. The advantages of this method are it avoids strong bases, low temperatures, and the need to transmetallate to main group metals for the coupling.
Modeling of unbalanced three‐phase driving‐point impedance with application to control of grid‐connected power converters
Authors: Li Zhen , Wong Siu‐Chung , Tse Chi K. , Liu Xiangdong 
Published: June 2015

SummaryThe dq transformation is widely used in the analysis and control of three‐phase symmetrical and balanced systems. The transformation is the real counterpart of the complex transformations derived from the symmetrical component theory. The widespread distributed generation and dynamically connected unbalanced loads in a three‐phase system inherently create unbalanced voltages to the point of common coupling. The unbalanced voltages will always be transformed as coupled positive‐sequence and negative‐sequence components with double‐frequency ripples that can be removed by some filtering algorithms in the dq frame. However, a technique for modeling unbalanced three‐phase impedance between voltages and currents of same sequences or of opposite sequences is still missing. We propose an effective method for modeling unbalanced three‐phase impedance using a decoupled zero‐sequence impedance and two interacting positive‐sequence and negative‐sequence balanced impedances in the dq frame. The proposed method can decompose a system with unbalanced resistance, inductance, or capacitance into a combination of independent reciprocal bases (IRB). Each IRB basis belongs to one of the positive‐sequence, negative‐sequence, or zero‐sequence system components to facilitate further analysis. The effectiveness of this approach is verified with a case study of an unbalanced load and another case study of an unbalanced voltage compensator in a microgrid application. Copyright © 2015 John Wiley & Sons, Ltd.
Diatoms as a tracer of hydrological connectivity: are they supply limited?
Authors: Coles Anna E. , Wetzel Carlos E. , Martínez‐Carreras Núria , Ector Luc , McDonnell Jeffrey J. , Frentress Jay , Klaus Julian , Hoffmann Lucien , Pfister Laurent 
Published: June 2015

AbstractRecent work has shown that aerial diatoms are a useful ecological tracer of hydrological connectivity in the hillslope–riparian zone–stream (HRS) system. While such work has improved both our understanding of catchment functioning and aerial diatom taxonomy, assemblages and distribution, further work is hampered by lack of data on diatom population depletion during rainfall events. We still do not know whether or not diatom tracers are supply limited. Here we test the null hypothesis that aerial diatoms exhibit infinite supply in the context of natural rainfall events. Rainfall simulation experiments were conducted in a small forested catchment in northwest Luxembourg. We extracted periodically soil surface samples and overland flow samples for diatom population size and species assemblage analyses. Diatom population size was quantified using a new approach we have developed, which involves extracting diatoms using carbonated water and an isopycnic separation technique. Our results showed that pre‐event population size was c. 96 100 diatoms per cm2 in the riparian zone. During the artificial rainfall event, the diatom population was depleted by 72% to 27 200 diatoms per cm2. The diatom assemblage was characteristic of a frequently disturbed environment. Overall, these results suggest that diatoms are supply limited, and are flushed significantly throughout rainfall events. Nevertheless, based on the data from these 1 in 10‐year rainstorm simulations, the riparian zone diatom population is unlikely to be exhausted on an event time scale. Further research is now underway to investigate the spatial and temporal variability of aerial diatom communities across a range of storm sizes. Copyright © 2015 John Wiley & Sons, Ltd.
Redox‐State Dependent Ligand Exchange in Manganese‐Based Oxidation Catalysis
Authors: Abdolahzadeh Shaghayegh , de Boer Johannes W. , Browne Wesley R. 
Published: June 2015

AbstractManganese‐based oxidation catalysis plays a central role both in nature, in the oxidation of water in photosystem II (PSII) and the control of reactive oxygen species, as well as in chemical processes, in the oxidation of organic substrates and bleaching applications. The focus of this review is on efforts made to explore and elucidate the redox‐dependent coordination chemistry of these manganese‐based systems in solution and the mechanisms by which their catalytic redox reactions proceed. We also examine the behaviour and activity of complexes that have been developed and used as models for the active sites of the corresponding enzymes, or used as catalysts in the oxidation of organic substrates. Given the current concern over the environmental and economic impact of chemical processes, manganese catalysts that use H2O2as oxidant are the primary focus of this review.
Synthesis and Characterisation of Various Diester and Triester Adducts of TiCl4
Authors: Blackburn Ben J. , Crane Jared H. , Knapp Caroline E. , Marchand Peter , Pugh David , Parkin Ivan P. , Carmalt Claire J. 
Published: June 2015

AbstractTitanium(IV) chloride and the triester glycerol tribenzoate (gtb) were reacted under moisture‐free conditions in order to investigate the use of triester‐containing oils in the purification of TiCl4 in industrial processes. This resulted in the isolation of a chloro‐bridged dimeric complex containing four titanium centres [{(TiCl4)2(gtb)}2] (1). Further novel coordination compounds of TiCl4 and the diesters; diisopropyl malonate, dibenzyl malonate and diethyl succinate were synthesised by direct reaction under moisture‐free conditions, yielding [TiCl4{CH2(COOiPr)2}] (2), [TiCl4{CH2(COOCH2Ph)2}] (3) and [TiCl4{C2H4(COOEt)2}] (4) respectively. The structures of compounds 1–4 were determined by single‐crystal X‐ray diffraction. All structures assumed an octahedral geometry consisting of the titanium bound to four chloride ligands and the diester molecule acting as a bidentate ligand, through its two carbonyl oxygen atoms. Exposure of the isopropyl malonate reaction to trace amounts of water during synthesis resulted in the formation of an oxo‐bridged dimeric structure [Ti2(μ‐O)Cl3{CH2(COOiPr)2}2] (2b), the structure of which was also obtained via single‐crystal X‐ray diffraction.
Production of lipid from depolymerised lignocellulose using the biocontrol yeast, Rhodotorula minuta: The fatty acid profile remains stable irrespective of environmental conditions
Authors: Sargeant Lisa A. , Mardell Matthew , Saad‐Allah Khalil M. , Hussein Ali H. , Whiffin Fraeya , Santomauro Fabio , Chuck Christopher J. 
Published: June 2015

The oleaginous yeast Rhodotorula minuta has been used previously as a biocide agent and for the production of β‐carotene. In addition, R. minuta has been shown to produce up to 40% lipids, while demonstrating a faster growth rate than the similar oleaginous yeasts; Lipomyces starkeyii and R. glutinis. In this study, this promising yeast was evaluated for its potential to produce glyceride lipids under the harsh conditions and complex sugar mixtures produced from depolymerised lignocellulose. The fatty acid profile of R. minuta was not found to change significantly irrespective of the environmental conditions and contained approximately 20% palmitic acid, 5% stearic acid, 60% oleic acid and 15% linolenic acid. R. minuta was found to grow on a range of sugars, and could consume xylose and glucose when both sugars were present; however, R. minuta was found to be highly sensitive to inhibitors, such as furfurals and organic acids, formed under the harsh lignocellulose depolymerisation conditions. Accordingly R. minuta did not grow well on biomass depolymerised with an acid pre‐treatment stage. However, R. minuta was cultured successfully on food waste depolymerised with no additional acids, producing up to 19 g/l cell mass with a lipid content of up to 25% of the dry cell weight.Practical applications: While high oil productivity, fast growth rates and a suitable fatty acid composition are key traits for the economic viability of SCO production, it is essential that the organism can be cultured and produce lipids from low‐cost substrates. This requires the ability to assimilate the nutrients present in the desired hydrolysate, as well as maintain high‐growth rates in the presence of inhibitory compounds produced during the hydrolysis process. In this paper, we demonstrate that the yeast R. minuta has industrial applicability in being able to convert depolymerised waste food to lipids with a profile akin to rapeseed oil.Rhodotorula minuta lipid cultured on depolymerised food waste.
Ureido‐Pyridazinone Derivatives: Insights into the Structural and Conformational Properties for STAT3 Inhibition
Authors: Meneghetti Fiorella , Villa Stefania , Masciocchi Daniela , Barlocco Daniela , Toma Lucio , Han Dong‐Cho , Kwon Byoung‐Mog , Ogo Naohisa , Asai Akira , Legnani Laura , Gelain Arianna 
Published: June 2015

AbstractThree new ureido‐pyridazinone derivatives, which are structurally related to the known STAT3 inhibitor AVS‐0288, were designed by taking into account the structure–activity relationships determined for several ureido‐oxadiazole derivatives previously studied by our group. Their synthesis was first attempted through suitable 5‐aminopyridazinone intermediates (6a and 6b), which molecular structures were confirmed by means of X‐ray diffraction data on 6a. Amine functionalization was unsuccessful, therefore, an alternative method was devised. Dual‐luciferase and AlphaScreen‐based assays were used to test their activity. The obtained data were rationalized on the basis of a modeling study, which focused our attention on the geometrical preferences of the ureido moiety. Computational results seem to indicate that both the 1,2,5‐oxadiazole ring and the extended ZZ arrangement are essential and probably act in a synergistic way to confer significant activity against STAT3.
A Non‐Enzymatic Glucose Sensor Based on Ni/MnO2 Nanocomposite Modified Glassy Carbon Electrode
Authors: Wang Yan , Bai Wushuang , Nie Fei , Zheng Jianbin 
Published: June 2015

AbstractA novel flower like 3D nickel/manganese dioxide (Ni/MnO2) nanocomposite was synthesized by a kind of simple electrochemical method and the formation mechanism of flower like structure was also researched. In addition, morphology and composition of the nanocomposite were characterized by scanning electron microscope (SEM), transmission electron microscopy (TEM), and X‐ray photoelectron spectroscopy (XPS). Then the Ni/MnO2 nanocomposites were applied to fabricate electrochemical non‐enzymatic glucose sensor. The electrochemical investigation for the sensor indicated that it possessed an excellent electrocatalytic property for glucose, and could applied to the quantification of glucose with a linear range from 2.5×10−7 to 3.5×10−3 M, a sensitivity of 1.04 mA mM−1 cm−2, and a detection limit of 1×10−7 M (S/N=3). The proposed sensor also presented attractive features such as interference‐free, and long‐term stability. The present study provided a general platform for the one‐step synthesis of nanomaterials with novel structure and can be extended to other optical, electronic and magnetic nanocompounds.
Biosensing Applications of V2O5‐CeO2 Mesoporous Silica
Authors: Luo Xi , Shu Hao , Wan Qijin , Wang Zhaohao , Yang Nianjun 
Published: June 2015

AbstractMesoporous silica has been functionalized with vanadium pentoxide (V2O5) and cerium oxide (CeO2). It was then immobilized with biocatalyst horseradish (HRP) to realize highly sensitive detection of H2O2. The electrode was characterized with SEM, cyclic voltammetry, and impedance measurements. A well‐defined peak for HRP reduction was noticed at about −0.31 V with an apparent heterogeneous electron transfer rate constant of 1.01 s−1. The catalytic reduction of H2O2 was achieved. The Michaelis constant was calculated to be 0.018 mM. On this electrode, H2O2 was detectable in the range of 20 to 180 µM and the detection limit was 3.0 µM.
Selective and Sensitive Determination of Uranyl Ions in Complex Matrices by Ion Imprinted Polymers‐Based Electrochemical Sensor
Authors: Kalate Bojdi Majid , Behbahani Mohammad , Najafi Mostafa , Bagheri Akbar , Omidi Fariborz , Salimi Sara 
Published: June 2015

AbstractWe report on the design of a UO22+‐selective electrode based on the use of UO22+ imprinted polymer nanoparticles (IP‐NPs), and its application for the differential pulse adsorptive cathodic stripping voltammetry determination of uranyl ions. A carbon paste electrode was modified with the IP‐NPs, and differential pulse adsorptive cathodic stripping voltammetry was applied as the detection technique after open‐circuit sorption of UO22+ ions. The modified electrode responses to UO22+ was linear in the 0.1 µg L−1 to 10 µg L−1 and in the 0.01 mg L−1 to 10 mg L−1. The method detection limit of the sensor was 0.03 µg L−1.
Rill length and plot‐scale effects on the hydrogeomorphologic response of gravelly roadbeds
Authors: Thomaz Edivaldo L. , Ramos‐Scharrón Carlos E. 
Published: June 2015

AbstractAlthough unpaved roads are well‐recognized as important sources of Hortonian overland flow and sediment in forested areas, their role in agriculturally‐active rural settings still lacks adequate documentation. In this study, we assessed the effect of micro‐catchment size, slope, and ground cover on runoff and sediment generation from graveled roadbeds servicing a rural area in southern Brazil. Fifteen replications based on 30‐min‐long simulated rainfall experiments were performed at constant rainfall intensities of 22–58 mm h−1 on roadbeds with varying characteristics including ~3–7 m2 micro‐catchment areas, 2–11° slopes, 2–9.7‐m‐long shallow rill features, and 30–100% gravel cover. The contributions of micro‐catchment size and rill length were the most important physical characteristics affecting runoff response and sediment production; both the size of the micro‐catchment and the length of the rills were inversely related to sediment loss and this contradicts most of the rill erosion literature. The effect of micro‐catchment size on runoff and sediment response suggests a potentially problematic spatial‐scale subjectivity of experimental plot results. The inverse relationship between rill length and sediment generation is interpreted here as related to the predominance of coarse fragments within rills, the inability of the shallow flows generated during the simulations to erode this sediment, and their role as zones of net sediment storage. Copyright © 2015 John Wiley & Sons, Ltd.