bluuebunny/crossref_metadata_2025_split huggingface dataset:
Wire‐Active Microrheology to Differentiate Viscoelastic Liquids from Soft Solids
Authors: Loosli Frédéric , Najm Matthieu , Chan Raymond , Oikonomou Evdokia , Grados Arnaud , Receveur Mathieu , Berret Jean‐François 
Published: November 2016

AbstractViscoelastic liquids are characterized by a finite static viscosity and a yield stress of zero, whereas soft solids have an infinite viscosity and a non‐zero yield stress. The rheological nature of viscoelastic materials has long been a challenge and is still a matter of debate. Here, we provide for the first time the constitutive equations of linear viscoelasticity for magnetic wires in yield‐stress materials, together with experimental measurements by using magnetic rotational spectroscopy (MRS). In MRS, the wires were subjected to a rotational magnetic field as a function of frequency and the motion of the wire was monitored by using time‐lapse microscopy. The studied soft solids were aqueous dispersions of gel‐forming polysaccharide (gellan gum) at concentrations above the gelification point. It was found that soft solids exhibited a clear and distinctive signature compared with viscous and viscoelastic liquids. In particular, the average wire rotation velocity equaled zero over a broad frequency range. We also showed that the MRS technique is quantitative. The equilibrium elastic modulus was retrieved from the wire oscillation amplitudes, and agrees with polymer‐dynamics theory.
Free‐Energy Landscape and Proton Transfer Pathways in Oxidative Deamination by Methylamine Dehydrogenase
Authors: Zelleke Theodros , Marx Dominik 
Published: November 2016

AbstractThe rate‐determining step in the reductive half‐reaction of the bacterial enzyme methylamine dehydrogenase, which is proton abstraction from the native substrate methylamine, is investigated using accelerated QM/MM molecular dynamics simulations at room temperature. Generation of the multidimensional thermal free‐energy landscape without restriction of the degrees of freedom beyond a multidimensional reaction subspace maps two rather similar pathways for the underlying proton transfer to one of two aspartate carboxyl oxygen atoms, termed OD1 and OD2, which hydrogen bond with Thr122 and Trp108, respectively. Despite significant large‐amplitude motion perpendicular to the one‐dimensional proton transfer coordinate, due to fluctuations of the donor–acceptor distance of about 3 Å, it is found that the one‐dimensional proton transfer free‐energy profiles are essentially identical to the minimum free‐energy pathways on the multidimensional free‐energy landscapes for both proton transfer channels. Proton transfer to one of the acceptor oxygen atoms—the OD2 site—is slightly favored in methylamine dehydrogenase by approximately 2 kcal mol−1, both kinetically and thermodynamically. Mechanistic analyses reveal that the hydrogen bond between Thr122β and OD1 is always present in the transition state independently of the proton transfer channel. Population analysis confirms that the electronic charge gained upon oxidation of the substrate is delocalized within the ring systems of the tryptophan tryptophylquinone cofactor.
Proton‐Gated Photoisomerization of Amino‐Substituted Dibenzofulvene Rotors
Authors: Jayasundara Udaya K. , Kim HyunJong , Sahteli Krishna P. , Cline Joseph I. , Bell Thomas W. 
Published: November 2016

AbstractDerivatives of 9‐(2,2,2‐triphenylethylidene)‐fluorene (TEF) undergo E/Z photoisomerization and are candidates for light‐powered molecular actuators and switches. The 2‐substituted derivatives bearing an amino group (ATEF) or a dimethylamino group (DTEF) are weakly photoactive in the absence of acids, but protonation increases photoisomerization quantum yields by factors of 30–60. Such compounds may be useful for incorporation into pH‐switchable photoactive devices.
Flexible Metal–Porphyrin Dimers (M=MnIIICl, CoII, NiII, CuII): Synthesis, Spectroscopy, Electrochemistry, Spectroelectrochemistry, and Theoretical Calculations
Authors: Li Minzhi , Zhang Qian , Xu Li , Zhu Weihua , Mack John , May Aviwe K. , Nyokong Tebello , Kobayashi Nagao , Liang Xu 
Published: November 2016

AbstractFour metalloporphyrin dimers linked by bridging amide‐bonded xanthene moieties and that contain either MnIII, CoII, NiII, or CuII metal centers were synthesized. Various spectroscopic, electrochemical, and spectroelectrochemical methods were used to study trends in their properties. Their electronic structure and optical properties were analyzed through a comparison of the electronic absorption and magnetic circular dichroism (MCD) spectral data with the results of time‐dependent (TD)‐DFT calculations.
Fast Degradation for High Activity: Oxygen‐ and Nitrogen‐Functionalised Carbon Nanotubes in Solid‐Acid Fuel‐Cell Electrodes
Authors: Naumov Olga , Naumov Sergej , Flyunt Roman , Abel Bernd , Varga Aron 
Published: November 2016

AbstractSimilar to polymer electrolyte membrane fuel cells, the widespread application of solid acid fuel cells (SAFCs) has been hindered partly by the necessity of the use of the precious‐metal catalyst Pt in the electrodes. Here we investigate multi‐walled carbon nanotubes (MWCNTs) for their potential catalytic activity by using symmetric cell measurements of solid‐acid‐based electrochemical cells in a cathodic environment. For all measurements, the carbon nanotubes were Pt free and subject to either nitrogen or oxygen plasma treatment. AC impedance spectroscopy of the electrochemical cells, with and without a DC bias, was performed and showed significantly lower initial impedances for oxygen‐plasma‐treated MWCNTs compared to those treated with a nitrogen plasma. In symmetric cell measurements with a DC bias, the current declines quickly for oxygen‐plasma‐treated MWCNTs and more slowly, over 12 days, for nitrogen‐plasma‐treated MWCNTs. To elucidate the degradation mechanisms of the oxygen‐plasma‐treated MWCNTs under SAFC operating conditions, theoretical calculations were performed using DFT. The results indicate that several degradation mechanisms are likely to occur in parallel through the reduction of the surface oxygen groups that were introduced by the plasma treatment. This finally leads to an inert MWCNT surface and a very low electrode performance. Nitrogen‐plasma‐treated MWCNTs appear to have a higher stability and may be worthwhile for future investigations.
Graphite Recycling from Spent Lithium‐Ion Batteries
Authors: Rothermel Sergej , Evertz Marco , Kasnatscheew Johannes , Qi Xin , Grützke Martin , Winter Martin , Nowak Sascha 
Published: November 2016

AbstractThe present work reports on challenges in utilization of spent lithium‐ion batteries (LIBs)—an increasingly important aspect associated with a significantly rising demand for electric vehicles (EVs). In this context, the feasibility of anode recycling in combination with three different electrolyte extraction concepts is investigated. The first method is based on a thermal treatment of graphite without electrolyte recovery. The second method additionally utilizes a subcritical carbon‐dioxide (subcritical CO2)‐assisted electrolyte extraction prior to thermal treatment. And the final investigated approach uses supercritical carbon dioxide (scCO2) as extractant, subsequently followed by the thermal treatment. It is demonstrated that the best performance of recycled graphite anodes can be achieved when electrolyte extraction is performed using subcritical CO2. Comparative studies reveal that, in the best case, the electrochemical performance of recycled graphite exceeds the benchmark consisting of a newly synthesized graphite anode. As essential efforts towards electrolyte extraction and cathode recycling have been made in the past, the electrochemical behavior of recycled graphite, demonstrating the best performance, is investigated in combination with a recycled LiNi1/3Co1/3Mn1/3O2 cathode.
Characterization of a BODIPY Dye as an Active Species for Redox Flow Batteries
Authors: Kosswattaarachchi Anjula M. , Friedman Alan E. , Cook Timothy R. 
Published: November 2016

AbstractAn all‐organic redox flow battery (RFB) employing a fluorescent boron‐dipyrromethene (BODIPY) dye (PM567) was investigated. In a RFB, the stability of the electrolyte in all charged states is critically linked to coulombic efficiency. To evaluate stability, bulk electrolysis and cyclic voltammetry (CV) experiments were performed. Oxidized and reduced, PM567 does not remain intact; however, the products of bulk electrolysis evolve over time to show stable redox behavior, making the dye a precursor for the active species of an RFB. A theoretical cell potential of 2.32 V was predicted from CV experiments with a working discharge voltage of approximately 1.6 V in a static test cell. Mass spectrometry was used to identify the products of bulk electrolysis. Related experiments were carried out using ferrocene and cobaltocenium hexafluorophosphate as redox‐stable benchmarks to further explain the stability results. The coulombic efficiency of a model cell using PM567 as a precursor for charge carriers stabilized around 73 %.
Organocatalytic Coupling of CO2 with Oxetane
Authors: Alves Margot , Grignard Bruno , Boyaval Amélie , Méreau Raphael , De Winter Julien , Gerbaux Pascal , Detrembleur Christophe , Tassaing Thierry , Jérôme Christine 
Published: November 2016

AbstractThe organocatalytic coupling of CO2 with oxetanes is investigated under solvent‐free conditions. The influence of the main reaction parameters (type of organocatalytic system, pressure, and temperature) on the yield, the product formed, and the selectivity of the reaction are discussed. An onium salt combined with a fluorinated alcohol promotes the efficient and selective organocatalytic synthesis of α,ω‐hydroxyl oligocarbonates by coupling CO2 with oxetanes at 130 °C and at a CO2 pressure as low as 2 MPa. NMR characterizations were correlated with matrix‐assisted laser desorption/ionization with time‐of‐flight mass spectrometer (MALDI‐TOF) analyses for elucidating the structure of the oligomers. Online FTIR studies under pressure, NMR titrations, and DFT calculations allowed an in‐depth understanding of the reaction mechanism. Finally, CO2‐based poly(carbonate‐co‐urethane)s were synthesized by step‐growth polymerization of hydroxyl telechelic oligocarbonates with 4,4′‐methylene diphenyl diisocyanate (MDI). The organocatalytic system described herein constitutes an innovative sustainable route to the selective preparation of hydroxyl telechelic carbonates of high interest for many applications, notably for the polyurethane business (especially for coatings or foams).
Carbocation/Polyol Systems as Efficient Organic Catalysts for the Preparation of Cyclic Carbonates
Authors: Rulev Yuri A. , Gugkaeva Zalina T. , Lokutova Anastasia V. , Maleev Victor I. , Peregudov Alexander S. , Wu Xiao , North Michael , Belokon Yuri N. 
Published: November 2016

AbstractCarbocation/polyol systems are shown to be highly efficient catalysts for the synthesis of cyclic carbonates from epoxides and carbon dioxide at 50 °C and 5 MPa CO2 pressure. The best activity was shown by the combination of crystal violet and 1,1′‐bi‐2‐naphthol (BINOL), which could be recycled five times with no loss of activity. The presence of specific interactions between the amino groups of the carbocation and the hydroxyl protons was confirmed by NMR experiments. The Job plots for the crystal violet iodide/BINOL and brilliant green iodide/BINOL systems showed that the catalytic systems consist of one molecule of the carbocation and one molecule of BINOL. Mechanistic studies using a deuterated epoxide indicate that there was some loss of epoxide stereochemistry during the reaction, but predominant retention of stereochemistry is observed. On this basis, a catalytic cycle is proposed.
Evaluation of the Effect of Sulfur on the Performance of Nickel/Gadolinium‐Doped Ceria Based Solid Oxide Fuel Cell Anodes
Authors: Riegraf Matthias , Yurkiv Vitaliy , Costa Rémi , Schiller Günter , Friedrich K. Andreas 
Published: November 2016

AbstractThe focus of this study is the measurement and understanding of the sulfur poisoning phenomena of Ni/gadolinium‐doped ceria (CGO) based solid oxide fuel cells (SOFC). Cells with Ni/CGO10 and NiCu5/CGO40 anodes were characterized by using impedance spectroscopy at different temperatures and H2/H2O fuel ratios. The short‐term sulfur poisoning behavior was investigated systematically at temperatures of 800–950 °C, current densities of 0–0.75 A cm−2, and H2S concentrations of 1–20 ppm. A sulfur poisoning mitigation effect was observed at high current loads and temperatures. The poisoning behavior was reversible for short exposure times. It was observed that the sulfur‐affected processes exhibited significantly different relaxation times that depend on the Gd content in the CGO phase. Moreover, it was demonstrated that the capacitance of Ni/CGO10 anodes is strongly dependent on the temperature and gas‐phase composition, which reflects a changing Ce3+/Ce4+ ratio.
Spatiotemporal differences in otoconial gene expression
Authors: Xu Yinfang , Zhang Yan , Lundberg Yunxia Wang 
Published: November 2016

AbstractOtoconia are minute biocrystals composed of glycoproteins, proteoglycans, and CaCO3, and are indispensable for sensory processing in the utricle and saccule. Otoconia abnormalities and degeneration can cause or facilitate crystal dislocation to the ampulla, leading to vertigo and imbalance in humans. In order to better understand the molecular mechanism controlling otoconia formation and maintenance, we have examined the spatial and temporal expression differences of otoconial genes in the mouse inner ear at developmental, mature and aging stages using whole transcriptome sequencing (RNA‐Seq) and quantitative RT‐PCR. We show that the expression levels of most otoconial genes are much higher in the utricle and saccule compared with other inner ear tissues before postnatal stages in C57Bl/6J mice, and the expression of a few of these genes is restricted to the embryonic utricle and saccule. After the early postnatal stages, expression of all otoconial genes in the utricle and saccule is drastically reduced, while a few genes gain expression dominance in the aging ampulla, indicating a potential for ectopic debris formation in the latter tissue at old ages. The data suggest that the expression of otoconial genes is tightly regulated spatially and temporally during developmental stages and can become unregulated at aging stages. Birth Defects Research (Part A) 106:613–625, 2016. © 2016 Wiley Periodicals, Inc.
The Impact of DSM‐5 on Eating Disorder Diagnoses
Authors: Vo Megen , Accurso Erin C. , Goldschmidt Andrea B. , Le Grange Daniel 
Published: November 2016

ABSTRACTObjectiveEating disorder diagnostic criteria were revised from the fourth to the fifth edition of the Diagnostic and Statistical Manual of Mental Disorders (DSM‐IV and −5, respectively). This study examines the impact of these revisions on rates of eating disorder diagnoses in treatment‐seeking youth.MethodParticipants were 651 youth, ages 7–18 years, presenting to an outpatient eating disorders program who met criteria for a DSM‐IV eating disorder diagnosis on intake. Patients completed well‐validated semi‐structured interviews to assess eating disorder psychopathology and psychiatric comorbidity.ResultsParticipants were predominantly female (n = 588; 90.3%) with an average age of 15.28 years (SD = 2.21), mean percent of median Body Mass Index (mBMI) of 101.91 (SD = 31.73), and average duration of illness of 16.74 months (SD = 17.63). Cases of DSM‐IV Eating Disorder Not Otherwise Specified (EDNOS), now most consistent with DSM‐5 Other Specified Feeding or Eating Disorder, decreased from 47.6% to 39.0%, Anorexia Nervosa increased from 29.6% to 33.5%, and Bulimia Nervosa increased from 22.7% to 24.7%.DiscussionConsistent with previous studies, and in keeping with the aims of the DSM‐5 for eating disorders, the revised diagnostic criteria reduced cases of DSM‐IV EDNOS and increased cases of specified eating disorders. © 2016 Wiley Periodicals, Inc.(Int J Eat Disord 2017; 50:578–581)
Application of structural equation mixture modeling to characterize the latent structure of eating pathology
Authors: Forbush Kelsie T. , Wildes Jennifer E. 
Published: November 2016

ABSTRACTObjectiveSeveral theoretical models describe the structure of eating disorders (EDs), and a burgeoning empirical literature has sought to identify whether eating pathology is conceptualized best as categorical (presence or absence of disorder), dimensional (continuous), or a hybrid of categories and dimensions.MethodsThis study used structural equation mixture modeling (SEMM) to identify the latent structure of EDs. Items from the Eating Pathology Symptoms Inventory (EPSI) were administered to individuals with EDs (N = 344). Select EPSI scales and body mass index were indicators in subsequent SEMM analyses. The Inventory of Depression and Anxiety Symptoms (IDAS), ED diagnoses, and select demographic variables were used as validators using chi‐square or MANOVA.ResultsCategorical models fit the data better than latent dimensional or hybrid models. Latent profile 1 (LP1) was non‐fat‐phobic restricting anorexia nervosa; LP2, an obese, binge‐eating class; LP3, non‐purging bulimia nervosa; LP4, fat‐phobic restricting anorexia nervosa; and LP5, multiple purging bulimia nervosa. External validation analyses indicated that LP4 and LP5 had the highest non‐ED‐related psychopathology.DiscussionThese findings indicate that there is substantial variability in the phenomenology of traditional DSM‐based ED categories across latent profiles, and highlight the salience of certain ED phenotypes that have been debated in the literature. © 2016 Wiley Periodicals, Inc.(Int J Eat Disord 2017; 50:542–550)
Host‐plant associated genetic divergence of two Diatraea spp. (Lepidoptera: Crambidae) stemborers on novel crop plants
Authors: Joyce Andrea L. , Sermeno Chicas Miguel , Serrano Cervantes Leopoldo , Paniagua Miguel , Scheffer Sonja J. , Solis M. Alma 
Published: November 2016

AbstractDiatraea lineolata and Diatraea saccharalis (Lepidoptera: Crambidae) are moths with stemboring larvae that feed and develop on economically important grasses. This study investigated whether these moths have diverged from a native host plant, corn, onto introduced crop plants including sorghum, sugarcane, and rice. Diatraea larvae were collected from these four host plants throughout the year in El Salvador and were reared on artificial diet until moths or parasitoids emerged. Adult moths were subsequently identified to species. Amplified fragment length polymorphisms (AFLPs) and mitochondrial DNA cytochrome oxidase I (COI) were used to examine whether or not there was genetic divergence of D. lineolata or D. saccharalis populations on the four host plants. Percent parasitism was also determined for each moth on its host plants. D. lineolata was collected from corn in the rainy season and sorghum in the dry season. D. saccharalis was most abundant on sugarcane in the rainy season and sorghum in the dry season. The AFLP analysis found two genetically divergent populations of both D. lineolata and D. saccharalis. Both moths had high levels of parasitism on their dominant host plant in the rainy season, yet had low levels of parasitism on sorghum in the dry season. The presence of two genotypes of both Diatraea spp. on sorghum suggest that host‐associated differentiation is occurring on this novel introduced crop plant.
Wind estimation based on thermal soaring of birds
Authors: Weinzierl Rolf , Bohrer Gil , Kranstauber Bart , Fiedler Wolfgang , Wikelski Martin , Flack Andrea 
Published: November 2016

AbstractThe flight performance of birds is strongly affected by the dynamic state of the atmosphere at the birds' locations. Studies of flight and its impact on the movement ecology of birds must consider the wind to help us understand aerodynamics and bird flight strategies. Here, we introduce a systematic approach to evaluate wind speed and direction from the high‐frequency GPS recordings from bird‐borne tags during thermalling flight. Our method assumes that a fixed horizontal mean wind speed during a short (18 seconds, 19 GPS fixes) flight segment with a constant turn angle along a closed loop, characteristic of thermalling flight, will generate a fixed drift for each consequent location. We use a maximum‐likelihood approach to estimate that drift and to determine the wind and airspeeds at the birds' flight locations. We also provide error estimates for these GPS‐derived wind speed estimates. We validate our approach by comparing its wind estimates with the mid‐resolution weather reanalysis data from ECMWF, and by examining independent wind estimates from pairs of birds in a large dataset of GPS‐tagged migrating storks that were flying in close proximity. Our approach provides accurate and unbiased observations of wind speed and additional detailed information on vertical winds and uplift structure. These precise measurements are otherwise rare and hard to obtain and will broaden our understanding of atmospheric conditions, flight aerodynamics, and bird flight strategies. With an increasing number of GPS‐tracked animals, we may soon be able to use birds to inform us about the atmosphere they are flying through and thus improve future ecological and environmental studies.
Linking modern coexistence theory and contemporary niche theory
Authors: Letten Andrew D. , Ke Po‐Ju , Fukami Tadashi 
Published: November 2016

AbstractModern coexistence theory and contemporary niche theory represent parallel frameworks for understanding the niche's role in species coexistence. Despite increasing prominence and shared goals, their compatibility and complementarity have received little attention. This paucity of overlap not only presents an obstacle to newcomers to the field, but it also precludes further conceptual advances at their interface. Here, we present a synthetic treatment of the two frameworks. We review their main concepts and explore their theoretical and empirical relationship, focusing on how the resource supply ratio, impact niche, and requirement niche of contemporary niche theory translate into the stabilizing and equalizing processes of modern coexistence theory. We show, for a general consumer–resource model, that varying resource supply ratios reflects an equalizing process; varying impact niche overlap reflects a stabilizing process; and varying requirement niche overlap may be both stabilizing and equalizing, but has no qualitative effect on coexistence. These generalizations provide mechanistic insight into modern coexistence theory, while also clarifying the role of contemporary niche theory's impacts and requirements in mediating coexistence. From an empirical perspective, we recommend a hierarchical approach, in which quantification of the strength of stabilizing mechanisms is used to guide more focused investigation into the underlying niche factors determining species coexistence. Future research that considers alternative assumptions, including different forms of species interaction, spatiotemporal heterogeneity, and priority effects, would facilitate a more complete synthesis of the two frameworks.