bluuebunny/crossref_metadata_2025 huggingface dataset:
Passive buoyant tracers in the ocean surface boundary layer: 1. Influence of equilibrium wind‐waves on vertical distributions
Authors: Kukulka T. , Brunner K.
Published: May 2015

This paper is the first of a two part series that investigates passive buoyant tracers in the ocean surface boundary layer. The first part examines the influence of equilibrium wind‐waves on vertical tracer distributions, based on large eddy simulations (LES) of the wave‐averaged Navier‐Stokes equation. The second part applies the model to investigate observations of buoyant microplastic marine debris, which has emerged as a major ocean pollutant. The LES model captures both Langmuir turbulence (LT) and enhanced turbulent kinetic energy input due to breaking waves (BW) by imposing equilibrium wind‐wave statistics for a range of wind and wave conditions. Concentration profiles of LES agree well with analytic solutions obtained for an eddy diffusivity profile that is constant near the surface and transitions into the K‐Profile Parameterization (KPP) profile shape at greater depth. For a range of wind and wave conditions, the eddy diffusivity normalized by the product of water‐side friction velocity and mixed layer depth, h, mainly depends on a single nondimensional parameter, the peak wavelength (which is related to Stokes drift decay depth) normalized by h. For smaller wave ages, BW critically enhances near‐surface mixing, while LT effects are relatively small. For greater wave ages, both BW and LT contribute to elevated near‐surface mixing, and LT significantly increases turbulent transport at greater depth. We identify a range of realistic wind and wave conditions for which only Langmuir (and not BW or shear driven) turbulence is capable of deeply submerging buoyant tracers.
Shear‐generated turbulence in the equatorial Pacific produced by small vertical scale flow features
Authors: Richards K. J. , Natarov A. , Firing E. , Kashino Y. , Soares S. M. , Ishizu M. , Carter G. S. , Lee J. H. , Chang K. I.
Published: May 2015

We investigate the characteristics of shear‐generated turbulence in the natural environment by considering data from a number of cruises in the western equatorial Pacific. In this region, the vertical shear of the flow is dominated by flow structures that have a relatively small vertical scale of O(10 m). Combining data from all cruises, we find a strong relationship between the turbulent dissipation rate, ϵ, vertical shear, S, and buoyancy frequency, N. Examination of ϵ at a fixed value of Richardson number, Ri = N2∕S2, shows that
for a wide range of values of N, where ut is an appropriate velocity scale which we assume to be the horizontal velocity scale of the turbulence. The implied vertical length scale, ℓv = ut∕N, is consistent with theoretical and numerical studies of stratified turbulence. Such behavior is found for Ri < 0.4. The vertical diffusion coefficient then scales as
at a fixed value of Richardson number. The amplitude of ϵ is found to increase with decreasing Ri, but only modestly, and certainly less dramatically than suggested by some parameterization schemes. Provided the shear generating the turbulence is resolved, our results point to a way to parameterize the unresolved turbulence.
Linkage between lateral circulation and near‐surface vertical mixing in a coastal plain estuary
Authors: Huguenard K. D. , Valle‐Levinson A. , Li M. , Chant R. J. , Souza A. J.
Published: May 2015

Microstructure and current velocity measurements were collected at a cross‐channel transect in the James River under spring and neap tidal conditions in May 2010 to study cross‐estuary variations in vertical mixing. Results showed that near‐surface mixing was related to lateral circulation during the ebb phase of a tidal cycle, and that the linkage was somewhat similar from neap to spring tides. During neap tides, near‐surface mixing was generated by the straining of lateral density gradients influenced by the advection of fresh, riverine water on the right side (looking seaward) of the transect. Spring tide results revealed similar findings on the right side of the cross section. However, on the left side, the straining by velocity shears acted in concert with density straining. Weak along‐estuary velocities over the left shoal were connected to faster velocities in the channel via a clockwise lateral circulation (looking seaward). These results provided evidence that in the absence of direct wind forcing, near‐surface vertical mixing can occur from mechanisms uncoupled from bottom friction.
Effects of a changing climate on summertime fine particulate matter levels in the eastern U.S.
Authors: Day Melissa C. , Pandis Spyros N.
Published: May 2015

The chemical transport model PMCAMx is used to examine the effect of climate change on fine (under 2.5 µms) particulate matter (PM2.5) during the summer in the eastern United States. Meteorology from 10 years in the 1990s (present) and 10 years in the 2050s (future) based on the Intergovernmental Panel on Climate Change A2 scenario is used. Anthropogenic pollutant emissions are assumed to remain constant, while biogenic emissions are climate sensitive and, depending on species, increase between 15 and 27% on average. The predicted changes of PM2.5 are modest (increases of less than 10% on average across the domain) and quite variable in space, ranging from +13% in the Plains to −7% in the Northeast. Variability is driven concurrently by changes in temperature, wind speed, rainfall, and relative humidity, with no single dominant meteorological factor. Sulfate and organic aerosol are responsible for most of the PM2.5 change. The improved treatment of organic aerosol using the volatility basis set does not increase significantly its sensitivity to climate change compared to traditional treatments that neglect the volatility of primary particles and do not simulate the chemical aging processes. Future organic aerosol is predicted to be more oxidized due to increases of its secondary biogenic and anthropogenic components. These results suggest that the effects of planned and expected emission anthropogenic emission controls will be more important than those of climate change for PM2.5 concentrations in 2050. Maximum daily 8 h average ozone increases by 5% on average are predicted, with a marked increase in the Northeast, Southeast, and Midwest.
Revising the slant column density retrieval of nitrogen dioxide observed by the Ozone Monitoring Instrument
Authors: Marchenko S. , Krotkov N. A. , Lamsal L. N. , Celarier E. A. , Swartz W. H. , Bucsela E. J.
Published: May 2015

Nitrogen dioxide retrievals from the Aura/Ozone Monitoring Instrument (OMI) have been used extensively over the past decade, particularly in the study of tropospheric air quality. Recent comparisons of OMI NO2 with independent data sets and models suggested that the OMI values of slant column density (SCD) and stratospheric vertical column density (VCD) in both the NASA OMNO2 and Royal Netherlands Meteorological Institute DOMINO products are too large, by around 10–40%. We describe a substantially revised spectral fitting algorithm, optimized for the OMI visible light spectrometer channel. The most important changes comprise a flexible adjustment of the instrumental wavelength shifts combined with iterative removal of the ring spectral features; the multistep removal of instrumental noise; iterative, sequential estimates of SCDs of the trace gases in the 402–465 nm range. These changes reduce OMI SCD(NO2) by 10–35%, bringing them much closer to SCDs retrieved from independent measurements and models. The revised SCDs, submitted to the stratosphere‐troposphere separation algorithm, give tropospheric VCDs ∼10–15% smaller in polluted regions, and up to ∼30% smaller in unpolluted areas. Although the revised algorithm has been optimized specifically for the OMI NO2 retrieval, our approach could be more broadly applicable.
The Fe snow regime in Ganymede's core: A deep‐seated dynamo below a stable snow zone
Authors: Rückriemen T. , Breuer D. , Spohn T.
Published: May 2015

Ganymede shows signs of a present‐day magnetic field, whose origin is thought to be in its core. The Fe snow regime has been suggested to be vital in Ganymede's history. In this regime, Fe crystals first form at the core‐mantle boundary and later settle to the deeper core due to their higher density (Fe snow). A stable chemical gradient arises within the liquid of the snow zone. Below the snow zone the Fe particles remelt. We propose that the remelting of Fe in the deeper, entirely liquid core initiates compositional convection, which could be the origin of the dynamo. Such a dynamo is restricted by the period of time the snow zone needs to grow across the core. We investigate this time period with a 1‐D core evolution model by varying the initial sulfur concentration, the core heat flux, and the thermal conductivity of the core. For the proposed dynamo in the deeper liquid core, we obtain necessary time periods of between 320 and 800 Myr and magnetic field strengths at the surface that match the observed value of 719 nT. To explain the present magnetic field, we favor cores with high sulfur concentrations because those lead to a late start and a long duration of the dynamo. Furthermore, a present dynamo below the snow zone suggests the absence of an inner core.
Analyzing the effects of excess rainfall properties on the scaling structure of peak discharges: Insights from a mesoscale river basin
Authors: Ayalew Tibebu B. , Krajewski Witold F. , Mantilla Ricardo
Published: May 2015

Key theoretical and empirical results from the past two decades have established that peak discharges resulting from a single rainfall‐runoff event in a nested watershed exhibit a power law, or scaling, relation to drainage area and that the parameters of the power law relation, henceforth referred to as the flood scaling exponent and intercept, change from event to event. To date, only two studies have been conducted using empirical data, both using data from the 21 km2 Goodwin Creek Experimental Watershed that is located in Mississippi, in an effort to uncover the physical processes that control the event‐to‐event variability of the flood scaling parameters. Our study expands the analysis to the mesoscale Iowa River basin (A = 32,400 km2), which is located in eastern Iowa, and provides additional insights into the physical processes that control the flood scaling parameters. Using 51 rainfall‐runoff events that we identified over the 12 year period since 2002, we show how the duration and depth of excess rainfall, which is the portion of rainfall that contributes to direct runoff, control the flood scaling exponent and intercept. Moreover, using a diagnostic simulation study that is guided by evidence found in empirical data, we show that the temporal structure of excess rainfall has a significant effect on the scaling structure of peak discharges. These insights will contribute toward ongoing efforts to provide a framework for flood prediction in ungauged basins.
Formation of ridges in a stable lithosphere in mantle convection models with a viscoplastic rheology
Authors: Rozel A. , Golabek G. J. , Näf R. , Tackley P. J.
Published: May 2015

Numerical simulations of mantle convection with a viscoplastic rheology usually display mobile, episodic or stagnant lid regimes. In this study, we report a new convective regime in which a ridge can form without destabilizing the surrounding lithosphere or forming subduction zones. Using simulations in 2‐D spherical annulus geometry, we show that a depth‐dependent yield stress is sufficient to reach this ridge only regime. This regime occurs when the friction coefficient is close to the critical value between mobile lid and stagnant lid regimes. Maps of convective regime as a function of the parameters friction coefficients and depth dependence of viscosity are provided for both basal heating and mixed heating situations. The ridge only regime appears for both pure basal heating and mixed heating mode. For basal heating, this regime can occur for all vertical viscosity contrasts, while for mixed heating, a highly viscous deep mantle is required.
Investigating uncertainties in empirical Green's function analysis of earthquake source parameters
Authors: Abercrombie Rachel E.
Published: May 2015

I use a well‐recorded earthquake sequence to investigate the uncertainties of earthquake stress drops calculated using an empirical Green's function (EGF) approach. The earthquakes in the largest (M ~ 2.1) repeating sequence targeted by the San Andreas Observatory at Depth (SAFOD), Parkfield, California, are recorded by multiple borehole stations and have simple sources, well‐constrained stress drops, and abundant smaller earthquakes to use as EGFs. I perform three tests to estimate quantitatively the likely uncertainties to arise in less optimal settings. I use EGF earthquakes with a range of cross‐correlation values and separation distances from the main earthquakes. The stress drop measurements decrease by a factor of 3 as the quality of the EGF assumption decreases; a good EGF must be located within approximately one source dimension of the large earthquake, with high cross correlation. I subsample the large number of measurements for the main earthquakes to investigate the expected stress drop uncertainties in studies where fewer stations or EGFs are available. If only one measurement is available, the uncertainties are likely to be at least 50%. The uncertainties decrease to <20% with five or more measurements; using multiple EGFs is a good alternative to multiple stations. To investigate the effects of limited frequency bandwidth, I recalculate the corner frequencies after progressively decimating the sample rate. Decreasing the high‐frequency limit of the bandwidth decreases the estimate of the corner frequency (and stress drop). The corner frequency may be underestimated if it is within a factor of 3 of the maximum frequency of the signal.
Climate change signal and uncertainty inCMIP5‐based projections of global ocean surface wave heights
Authors: Wang Xiaolan L. , Feng Yang , Swail Val R.
Published: May 2015

This study uses the analysis of variance approaches to quantify the climate change signal and uncertainty in multimodel ensembles of statistical simulations of significant wave height (Hs), which are based on the CMIP5 historical, RCP4.5 and RCP8.5 forcing scenario simulations of sea level pressure. Here the signal of climate change refers to the temporal variations caused by the prescribed forcing. “Significant” means “significantly different from zero at 5% level.” In a four‐model ensemble ofHssimulations, the common signal—the signal that is simulated in all the four models—is found to strengthen over time. For the historical followed by RCP8.5 scenario, the common signal in annual meanHsis found to be significant in 16.6% and 82.2% of the area by year 2005 and 2099, respectively. The global average of the variance proportion of the common signal increases from 0.75% in year 2005 to 12.0% by year 2099. The signal is strongest in the eastern tropical Pacific (ETP), featuring significant increases in both the annual mean and maximum ofHsin this region. The climate model uncertainty (i.e., intermodel variability) is significant nearly globally; its magnitude is comparable to or greater than that of the common signal in most areas, except in the ETP where the signal is much larger. In a 20‐model ensemble ofHssimulations for the period 2006–2099, the model uncertainty is found to be significant globally; it is about 10 times as large as the variability between the RCP4.5 and RCP8.5 scenarios.
Changes in dissolved organic carbon and total dissolved nitrogen fluxes across subtropical forest ecosystems at different successional stages
Authors: Yan Junhua , Li Kun , Wang Wantong , Zhang Deqiang , Zhou Guoyi
Published: May 2015

Lateral transports of carbon and nitrogen are important processes linking terrestrial ecosystems and aquatic systems. Most previous studies made in temperate forests found that fluxes of carbon and nitrogen by runoff water varied in different forests, but few studies have been made in subtropical forests. This study was to investigate dissolved organic carbon (DOC) and total dissolved nitrogen (TDN) fluxes at the catchment scale along a subtropical forest succession gradient from pine forest (pioneer) to coniferous and broadleaved mixed forest (transitional) to broadleaved forest (mature). Our results showed that DOC concentration significantly decreased (p<0.001) while TDN concentration significantly increased (p<0.001) in runoff water from pioneer to mature forests, which in turn resulted in a decrease in DOC flux and an increase in TDN flux, as mean annual runoff did not vary significantly among three succession forest catchments. The mean (±standard deviation) annual DOC flux was 118.1±43.6, 88.3±16.7 and 77.2±11.7 kg ha−1 yr−1for pioneer, transitional and mature forest catchments, respectively; and the mean annual TDN flux was 9.9 ±2.7, 18.2±3.0 and 21.2 ±4.5 kg ha−1 yr−1for pioneer, transitional and mature forest catchments, respectively. The mature forest reduced DOC flux by increased soil chemical adsorption and physical protection. An increase in TDN flux from pioneer to mature forests was consistent with the previous finding that mature forest was nitrogen saturated while pioneer forest was nitrogen limited. Therefore large‐scale conversion of pioneer forests to transitional or mature forests in subtropical China will reduce DOC concentration and increase TDN concentration in the down‐stream water, which may have significant impact on its water quality and aquatic biological activities.
Short‐Term Power Generation Scheduling via Robust Optimization
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Authors: Zhao Chaoyue , Chen Yonghong , Guan Yongpei , Wang Qianfan , Wang Xing
Published: May 2015

Recently, the portion of renewable energy in power supply has been increasing dramatically. Meanwhile, renewable energy's intermittent nature brings challenges for power system operations, in particular for short‐term power generation scheduling. Recently developed robust optimization approaches can help reliability unit commitment runs at ISOs to maintain system reliability. In this article, we review selected recent studies, mainly the ones co‐authored by one of the authors for this article, on exploring robust optimization models and solution approaches to solve reliability unit commitment problems at ISOs.
A cooperative formation‐based collision avoidance approach for a group of autonomous vehicles
Authors: Yang Aolei , Naeem Wasif , Fei Minrui , Tu Xiaowei
Published: May 2015

This paper employs a unique decentralised cooperative control method to realise a formation‐based collision avoidance strategy for a group of autonomous vehicles. In this approach, the vehicles' role in the formation and their alert and danger areas are first defined, and the formation‐based intra‐group and external collision avoidance methods are then proposed to translate the collision avoidance problem into the formation stability problem. The extension–decomposition–aggregation formation control method is next employed to stabilise the original and modified formations, whilst manoeuvring, and subsequently solve their collision avoidance problem indirectly. Simulation study verifies the feasibility and effectiveness of the intra‐group and external collision avoidance strategy. It is demonstrated that both formation control and collision avoidance problems can be simultaneously solved if the stability of the expanded formation including external obstacles can be satisfied. Copyright © 2015 John Wiley & Sons, Ltd.
Sinusoidal disturbance rejection in chaotic planar oscillators
Authors: Menini Laura , Possieri Corrado , Tornambè Antonio
Published: May 2015

The main goal of this paper is to design a compensator able to restore the nominal behavior of a planar system, which is rendered chaotic by an unmeasurable sinusoidal disturbance input. To reach such a goal, some instruments, taken from algebraic geometry, are used to estimate the unmeasurable disturbance from the time derivatives of the output of the system and of the control input. Copyright © 2015 John Wiley & Sons, Ltd.
State estimation and data fusion for multirate sensor networks
Authors: Yan Liping , Jiang Lu , Xia Yuanqing , Fu Mengyin
Published: May 2015

This article is concerned with state estimation and data fusion of a linear dynamic system observed by multirate sensors in the environment of wireless sensor networks. The sampling, estimation, and transmission rates in the wireless sensor networks are different. We derive the optimal linear estimation in the centralized, sequential, and distributed forms. A numerical example is given to show the feasibility and effectiveness of the proposed algorithms. Copyright © 2015 John Wiley & Sons, Ltd.
A High‐Capacitance Salt‐Free Dielectric for Self‐Healable, Printable, and Flexible Organic Field Effect Transistors and Chemical Sensor
Authors: Huang Weiguo , Besar Kalpana , Zhang Yong , Yang Shyuan , Wiedman Gregory , Liu Yu , Guo Wenmin , Song Jian , Hemker Kevin , Hristova Kalina , Kymissis Ionnis J. , Katz Howard E.
Published: May 2015

Printable and flexible electronics attract sustained attention for their low cost, easy scale up, and potential application in wearable and implantable sensors. However, they are susceptible to scratching, rupture, or other damage from bending or stretching due to their “soft” nature compared to their rigid counterparts (Si‐based electronics), leading to loss of functionality. Self‐healing capability is highly desirable for these “soft” electronic devices. Here, a versatile self‐healing polymer blend dielectric is developed with no added salts and it is integrated into organic field transistors (OFETs) as a gate insulator material. This polymer blend exhibits an unusually high thin film capacitance (1400 nF cm−2 at 120 nm thickness and 20–100 Hz). Furthermore, it shows pronounced electrical and mechanical self‐healing behavior, can serve as the gate dielectric for organic semiconductors, and can even induce healing of the conductivity of a layer coated above it together with the process of healing itself. Based on these attractive properties, we developed a self‐healable, low‐voltage operable, printed, and flexible OFET for the first time, showing promise for vapor sensing as well as conventional OFET applications.
A Robust Ion‐Conductive Biopolymer as a Binder for Si Anodes of Lithium‐Ion Batteries
Authors: Liu Jie , Zhang Qian , Zhang Tao , Li Jun‐Tao , Huang Ling , Sun Shi‐Gang
Published: May 2015

Binders have been reported to play a key role in improving the cycle performance of Si anode materials of lithium‐ion batteries. In this study, the biopolymer guar gum (GG) is applied as the binder for a silicon nano­particle (SiNP) anode of a lithium‐ion battery for the first time. Due to the large number of polar hydroxyl groups in the GG molecule, a robust interaction between the GG binder and the SiNPs is achieved, resulting in a stable Si anode during cycling. More specifically, the GG binder can effectively transfer lithium ions to the Si surface, similarly to polyethylene oxide solid electrolytes. When GG is used as a binder, the SiNP anode can deliver an initial discharge capacity as high as 3364 mAh g−1, with a Coulombic efficiency of 88.3% at the current density of 2100 mA g−1, and maintain a capacity of 1561 mAh g−1 after 300 cycles. The study shows that the electrochemical performance of the SiNP anode with GG binder is significantly improved compared to that of a SiNP anode with a sodium alginate binder, and it demonstrates that GG is a promising binder for Si anodes of lithium‐ion batteries.
Artificial Metalloenzymes in Asymmetric Catalysis: Key Developments and Future Directions
Authors: Pàmies Oscar , Diéguez Montserrat , Bäckvall Jan‐E.
Published: May 2015

Artificial metalloenzymes combine the excellent selective recognition/binding properties of enzymes with transition metal catalysts, and therefore many asymmetric transformations can benefit from these entities. The search for new successful strategies in the construction of metal‐enzyme hybrid catalysts has therefore become a very active area of research. This review discusses all the developed strategies and the latest advances in the synthesis and application in asymmetric catalysis of artificial metalloenzymes with future directions for their design, synthesis and application (Sections 2–4). Finally, advice is presented (to the non‐specialist) on how to prepare and use artificial metalloenzymes (Section 5).

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Intensification and kinetics of methane hydrate formation under heat removal by phase change of n‐tetradecane
Authors: Song Xiaofei , Xin Feng , Yan Hongchao , Li Xingang , Jia Hongri
Published: May 2015

A method of direct heat removal resulting from the phase change of n‐tetradecane was used to intensify the heat transfer during hydrate formation. The growth rates of methane hydrate in aqueous slurries containing 25–45 wt % of solid n‐tetradecane were investigated at pressures between 4.70 and 6.46 MPa (gauge) and near the fusion point of solid n‐tetradecane. Methane hydrate growth started at a practically constant rate, which became variable after a sudden increase. Two rate laws were established to correlate with the experimental data for the constant and variable rate stages. The methane hydrate growth rates achieved with solid n‐tetradecane were significantly enhanced compared with those obtained under indirect heat removal. © 2015 American Institute of Chemical Engineers AIChE J, 61: 3441–3450, 2015
The First Introduction of Graphene to Rechargeable Li–CO2 Batteries
Authors: Zhang Zhang , Zhang Qiang , Chen Yanan , Bao Jie , Zhou Xianlong , Xie Zhaojun , Wei Jinping , Zhou Zhen
Published: May 2015

The utilization of the greenhouse gas CO2 in energy‐storage systems is highly desirable. It is now shown that the introduction of graphene as a cathode material significantly improves the performance of Li–CO2 batteries. Such batteries display a superior discharge capacity and enhanced cycle stability. Therefore, graphene can act as an efficient cathode in Li–CO2 batteries, and it provides a novel approach for simultaneously capturing CO2 and storing energy.
Sigillin A, eine einzigartige polychlorierte Wehrsubstanz gegen Arthropoden aus dem Schneefloh Ceratophysella sigillata
Authors: Schmidt Witali , Schulze Thies M. , Brasse Gregor , Nagrodzka Edyta , Maczka Michael , Zettel Jürg , Jones Peter G. , Grunenberg Jörg , Hilker Monika , Trauer‐Kizilelma Ute , Braun Ute , Schulz Stefan
Published: May 2015

Der winteraktive Springschwanz Ceratophysella sigillata produziert einzigartige polychlorierte Octahydroisocumarine um Fressfeinde abzuschrecken. Die Struktur der Hauptverbindung Sigillin A wurde durch Isolierung, spektroskopische Untersuchungen und Röntgenstrukturanalyse aufgeklärt. Sigillin A zeigte in einem Biotest mit räuberischen Ameisen eine hohe abschreckende Wirkung. Ein vielversprechender Syntheseansatz für diese neue Klasse von Naturstoffen wurde entwickelt.
A Universal Strategy for Aptamer‐Based Nanopore Sensing through Host–Guest Interactions inside α‐Hemolysin
Authors: Li Ting , Liu Lei , Li Yuru , Xie Jiani , Wu Hai‐Chen
Published: May 2015

Nanopore emerged as a powerful single‐molecule technique over the past two decades, and has shown applications in the stochastic sensing and biophysical studies of individual molecules. Here, we report a versatile strategy for nanopore sensing by employing the combination of aptamers and host–guest interactions. An aptamer is first hybridized with a DNA probe which is modified with a ferrocene⊂cucurbit[7]uril complex. The presence of analytes causes the aptamer–probe duplex to unwind and release the DNA probe which can quantitatively produce signature current events when translocated through an α‐hemolysin nanopore. The integrated use of magnetic beads can further lower the detection limit by approximately two to three orders of magnitude. Because aptamers have shown robust binding affinities with a wide variety of target molecules, our proposed strategy should be universally applicable for sensing different types of analytes with nanopore sensors.
Copper‐Promoted Sandmeyer Difluoromethylthiolation of Aryl and Heteroaryl Diazonium Salts
Authors: Wu Jiang , Gu Yang , Leng Xuebing , Shen Qilong
Published: May 2015

An efficient copper‐promoted difluoromethylthiolation of aryl and heteroaryl diazonium salts is described. The reaction is conducted under mild reaction conditions and various functional groups were compatible. In addition, reactions of heteroaryl diazonium salts such as pyridyl, quinolinyl, benzothiazolyl, thiophenyl, carbazolyl, and pyrazolyl diazonium salts occurred smoothly to afford the medicinally important difluoromethylthiolated heteroarenes. Furthermore, a more practical one‐pot direct diazotization and difluoromethylthiolation protocol was developed, and it converts the aniline derivatives into difluoromethylthiolated arenes. The utility of the method is demonstrated by difluoromethylthiolation of a number of natural products and drug molecules.
Sigillin A, a Unique Polychlorinated Arthropod Deterrent from the Snow Flea Ceratophysella sigillata
Authors: Schmidt Witali , Schulze Thies M. , Brasse Gregor , Nagrodzka Edyta , Maczka Michael , Zettel Jürg , Jones Peter G. , Grunenberg Jörg , Hilker Monika , Trauer‐Kizilelma Ute , Braun Ute , Schulz Stefan
Published: May 2015

The snow flea Ceratophysella sigillata, a winter‐active species of springtail, produces unique polychlorinated octahydroisocoumarins to repel predators. The structure of the major compound, sigillin A, was elucidated through isolation, spectroscopic analysis, and X‐ray crystallography. Sigillin A showed high repellent activity in a bioassay with predatory ants. A promising approach for the total synthesis of members of this new class of natural compounds was also developed.
Preparation and characterization of a type of ladder‐like poly(phenyl silsesquioxane) based hybrid star‐shaped copolymer of ε‐caprolactone
Authors: Yang Xiongfa , Cao Cheng , Chen Zhonghong , Liu Jia , Bassindale Alan R. , Lai Guoqiao
Published: May 2015

Combination of the organic–inorganic hybrid such as silsesquioxane with ε‐caprolactone will lead to materials expected to be environmentally friendly and applicable to biomedical usages. A ladder‐like poly(phenyl silsesquioxane) based hybrid star‐shaped copolymer of ε‐caprolactone was prepared by ring opening polymerization of ε‐caprolactone catalyzed by Sn(Oct)2 with hydroxyl terminated ladder‐like poly(phenyl silsesquioxane) as initiator. The copolymers were characterized by proton nuclear magnetic resonance (1H‐NMR), silicon nuclear magnetic resonance (29Si‐NMR), Fourier‐transform infrared spectrometer (FT‐IR), size exclusion chromatography (SEC), thermo gravimetric analysis (TGA), and differential scanning calorimetry (DSC) in detail. Furthermore, the enzymatic degradation property of the copolymers was also investigated. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42335.
PEGylation of MnO nanoparticles via catechol–Mn chelation to improving T1‐weighted magnetic resonance imaging application
Authors: Huang Haitao , Yue Tao , Xu Yanyun , Xu Ke , Xu Haibo , Liu Shiyuan , Yu Jiahui , Huang Jin
Published: May 2015

To enhance biocompatibility and physiological stability of hydrophobic MnO nanoparticles as contrast agent of T1‐weighted magnetic resonance imaging (MRI), dopamine‐functionalized poly(ethylene glycol) (PEG) was used to coat the surface of about 5 nm MnO nanoparticles. Although hydrophilic coating might decrease longitudinal relaxivity due to inhibiting the intimate contact between manganese of nanoparticle surface and proton in water molecules, higher longitudinal relaxivity was still maintained by manipulating the PEGylation degree of MnO nanoparticles. Moreover, in vivo MRI demonstrated considerable signal enhancement in liver and kidney using PEGylated MnO nanoparticles. Interestedly, the PEGylation induced the formation of about 120 nm clusters with high stability in storing and physiological conditions, indicating passive targeting potential to tumor and prolonged circulation in blood. In addition, the cytotoxicity of PEGylated MnO nanoparticles also proved negligible. Consequently, the convenient PEGylation strategy toward MnO nanoparticles could not only realize a good “trade‐off” between hydrophilic modification and high longitudinal relaxivity but also contribute additional advantages, such as passive targeting to tumor and long blood circulation, to MRI diagnosis of tumor. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42360.
A highly selective polybenzimidazole‐4,4′‐(hexafluoroisopropylidene)bis(benzoic acid) membrane for high‐temperature hydrogen separation
Authors: Choi Sun Hee , Kim Da Hye , Kim Do Young , Han Jun Young , Yoon Chang Won , Ham Hyung Chul , Kim Jin‐Ho , Kim Hyoung‐Juhn , Nam Suk Woo , Lim Tae‐Hoon , Han Jonghee
Published: May 2015

A polymeric gas separation membrane utilizing polybenzimidazole based on 4,4′‐(hexafluoroisopropylidene)bis(benzoic acid) was prepared. The synthesized membrane has an effective permeating area of 8.3 cm2and a thickness of 30 ± 2 µm. Gas permeation properties of the membrane were determined using H2, CO2, CO, and N2at temperatures ranging from 24°C to 200°C. The PBI‐HFA membranes not only exhibited excellent H2permeability, but it also displayed superior gas separation performance particularly for H2/N2and H2/CO2. The permeation parameters for both permeability and selectivity [and α(H2/N2);and α(H2/CO2)] obtained for the new material were found to be dependent on trans‐membrane pressure difference as well as temperature, and were found to surpass those reported by Robeson in 2008. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci.2015,132, 42371.
Effects of shell crosslinking on polyurea microcapsules containing a free‐radical initiator
Authors: McFarland Brian , Pojman John A.
Published: May 2015

Microencapsulation of a material is often used when a controlled release of a substance is desired. This study examines the effects of crosslinking in polyurea microcapsule shells on stability of microcapsules containing the free‐radical initiator cumene hydroperoxide (CHP). Crosslinking of polyurea shells was varied by using amine monomers containing different amine functionalities, and/or changing the isocyanate/primary amine ratio. Thermogravimetric analysis was performed to determine thermal properties of these microcapsules, and the pot lives of monomer systems containing these microcapsules were measured. Thermal stability is greater with a moderate degree of crosslinking from a trifunctional amine, and decreases when crosslinking is increased through use of higher amine functionality. Stability in monomer media generally increases with increased crosslinking through higher amine functionality, but is less predictable due to crosslinks formed between capsules. Generally, increasing crosslinking through altering the isocyanate to primary amine ratio decreases capsule stability in both dry and monomer storage. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42408.
2D Inorganic–Antimalarial Drug–Polymer Hybrid with pH‐Responsive Solubility
Authors: Kim Ji‐Yeong , Yang Jae‐Hun , Lee Ji‐Hee , Choi Goeun , Park Dae‐Hwan , Jo Mi‐Rea , Choi Soo‐Jin , Choy Jin‐Ho
Published: May 2015

Artesunic acid (ASH), an antimalarial drug, has low oral bioavailability due to its low aqueous solubility. To overcome this problem, artesunate (AS) was intercalated into zinc basic salt (ZBS) via co‐precipitation. AS was immobilized with a tilted double layer arrangement, which was also confirmed by XRD and 1‐D electron density mapping. In order to decrease the release rate of AS under gastrointestinal conditions and to simultaneously increase the release rate of AS under intestinal conditions, ZBS‐AS was coated with EUDRAGIT L100 (ZBS‐AS‐L100). Finally, we performed an in‐vivo pharmacokinetic study to compare the oral bioavailability of AS of ZBS‐AS‐L100 with that of ASH. Surprisingly, it was found that the former is 5.5 times greater than the latter due to an enhanced solubility of AS thanks to the ternary hybridization with ZBS and EUDRAGIT L100. Therefore, the present ZBS‐AS‐L100 system has a great potential as a novel antimalarial drug formulation with pH selectivity and enhanced bioavailability.
Simultaneous Perturbation Stochastic Approximation with Norm‐Limited Update Vector
Authors: Tanaka Yosuke , Azuma Shun‐ichi , Sugie Toshiharu
Published: May 2015

This paper addresses the convergence of simultaneous perturbation stochastic approximation (SPSA) with a norm‐limited update vector. We first illustrate an unstable solution of the standard SPSA algorithm which motivates the consideration of a modified version, where the norm of the update vector is limited to a certain value. Next, a result on the almost‐sure convergence is presented by reducing the modified algorithm into the standard SPSA algorithm and restricting the probability distribution for the perturbation to a Bernoulli distribution. Finally, we apply the modified algorithm to a system identification problem to demonstrate its performance.
A model for the layout of bike stations in public bike‐sharing systems
Authors: Chen Qun , Sun Tingyuan
Published: May 2015

The problem of designing a layout of bike stations for public bike‐sharing systems entails selecting a number of stations and then constructing them within a planning area having many bike traffic zones and candidate bike stations. In this paper, we proposed a mathematical model to formulate the layout of public bike stations with the objective of minimizing users' total travel time and investment budget constraints. The model can guarantee that the needs for picking up and dropping off bikes amidst all bike travel demands are satisfied. Using this model, the number and locations of bike stations and the number of bikes and parking lockers at each bike station can be simultaneously determined. A typical example solved by lingo solver is created to illustrate the proposed model. Copyright © 2015 John Wiley & Sons, Ltd.
Motor Circuit Anatomy in Children with Autism Spectrum Disorder With or Without Attention Deficit Hyperactivity Disorder
Authors: Mahajan Rajneesh , Dirlikov Benjamin , Crocetti Deana , Mostofsky Stewart H.
Published: May 2015

This study examined the morphology of frontal‐parietal regions relevant to motor functions in children with autism spectrum disorder (ASD) with or without attention deficit hyperactivity disorder (ADHD). We also explored its associations with autism severity and motor skills, and the impact of comorbid ADHD on these associations. Participants included 126 school‐age children: 30 had ASD only, 33 had ASD with ADHD, and 63 were typically developing. High resolution 3T MPRAGE images were acquired to examine the cortical morphology (gray matter volume, GMV, surface area, SA, and cortical thickness, CT) in three regions of interest (ROI): precentral gyrus (M1), postcentral gyrus (S1), and inferior parietal cortex (IPC). Children with ASD showed abnormal increases in GMV and SA in all three ROIs: (a) increased GMV in S1 bilaterally and in right M1 was specific to children with ASD without ADHD; (b) all children with ASD (with or without ADHD) showed increases in the left IPC SA. Furthermore, on measures of motor function, impaired praxis was associated with increased GMV in right S1 in the ASD group with ADHD. Children with ASD with ADHD showed a positive relationship between bilateral S1 GMV and manual dexterity, whereas children with ASD without ADHD showed a negative relationship. Our findings suggest that (a) ASD is associated with abnormal morphology of cortical circuits crucial to motor control and learning; (b) anomalous overgrowth of these regions, particularly S1, may contribute to impaired motor skill development, and (c) functional and morphological differences are apparent between children with ASD with or without ADHD. Autism Res 2015. © 2015 International Society for Autism Research, Wiley Periodicals, Inc.
Late‐life Depression, Suicidal Ideation, and Attempted Suicide: The Role of Individual Differences in Maximizing, Regret, and Negative Decision Outcomes
Authors: Bruine de Bruin Wändi , Dombrovski Alexandre Y. , Parker Andrew M. , Szanto Katalin
Published: May 2015

Suicide rates are highest in adults of middle and older age. Research with psychiatric patients has shown that proneness to feel regret about past decisions can grow so intense that suicide becomes a tempting escape. Here, we examine the additional role of individual differences in maximizing, or the tendency to strive for the best decision, rather than one that is good enough. We provided individual‐difference measures of maximizing, regret proneness, and negative life decision outcomes (as reported on the Decision Outcome Inventory) to a nonpsychiatric control group, as well as three groups of psychiatric patients in treatment for suicide attempts, suicidal ideation, or non‐suicidal depression. We found that scores on the three individual‐difference measures were worse for psychiatric patients than for nonpsychiatric controls and were correlated to clinical assessments of depression, hopelessness, and suicidal ideation. More importantly, maximizing was associated with these clinical assessments, even after taking into account maximizers' worse life decision outcomes. Regret proneness significantly mediated those relationships, suggesting that maximizers could be at risk for clinical depression because of their proneness to regret. We discuss the theoretical relevance of our findings and their promise for clinical practice. Ultimately, late‐life depression and suicidal ideation may be treated with interventions that promote better decision making and regret regulation. Copyright © 2015 John Wiley & Sons, Ltd.
Synthesis of highly fluorescent nitrogen and phosphorus doped carbon dots for the detection of Fe3+ ions in cancer cells
Authors: Chandra Soumen , Laha Dipranjan , Pramanik Arindam , Ray Chowdhuri Angshuman , Karmakar Parimal , Sahu Sumanta Kumar
Published: May 2015

Highly fluorescent nitrogen and phosphorus‐doped carbon dots with a quantum yield 59% have been successfully synthesized from citric acid and di‐ammonium hydrogen phosphate by single step hydrothermal method. The synthesized carbon dots have high solubility as well as stability in aqueous medium. The as‐obtained carbon dots are well monodispersed with particle sizes 1.5–4 nm. Owing to a good tunable fluorescence property and biocompatibility, the carbon dots were applied for intercellular sensing of Fe3+ ions as well as cancer cell imaging. Copyright © 2015 John Wiley & Sons, Ltd.
Assessment of tandem mass spectrometry and high‐resolution mass spectrometry for the analysis of bupivacaine in plasma
Authors: Gaudette Fleur , Benito Javier , Steagall Paulo , Beaudry Francis
Published: May 2015

Triple quadrupole mass spectrometers coupled with high performance liquid chromatography are workhorses in quantitative bioanalyses. They provide substantial benefits including reproducibility, sensitivity and selectivity for trace analysis. Selected reaction monitoring allows targeted assay development but datasets generated contain very limited information. Data mining and analysis of nontargeted high‐resolution mass spectrometry profiles of biological samples offer the opportunity to perform more exhaustive assessments, including quantitative and qualitative analysis. The objectives of this study were to test method precision and accuracy, to statistically compare bupivacaine drug concentration in real study samples and to verify if high‐resolution and accurate mass data collected in scan mode can actually permit retrospective data analysis, more specifically, extract metabolite related information. The precision and accuracy data presented using both instruments provided equivalent results. Overall, the accuracy ranged from 106.2 to 113.2% and the precision observed was from 1.0 to 3.7%. Statistical comparisons using a linear regression between both methods revealed a coefficient of determination (R2) of 0.9996 and a slope of 1.02, demonstrating a very strong correlation between the two methods. Individual sample comparison showed differences from −4.5 to 1.6%, well within the accepted analytical error. Moreover, post‐acquisition extracted ion chromatograms at m/z 233.1648 ± 5 ppm (M − 56) and m/z 305.2224 ± 5 ppm (M + 16) revealed the presence of desbutyl‐bupivacaine and three distinct hydroxylated bupivacaine metabolites. Post‐acquisition analysis allowed us to produce semi‐quantitative evaluations of the concentration–time profiles for bupicavaine metabolites. Copyright © 2015 John Wiley & Sons, Ltd.
Firms’ Response to Climate Change: The Interplay of Business Uncertainty and Organizational Capabilities
Authors: Lee Su‐Yol , Klassen Robert D.
Published: May 2015

With climate change emerging as one of the most important issues increasing uncertainty in the business circle, firms have shown different reactions. Why do firms differ in adopting and implementing carbon management practices (CMPs) in response to the global warming issue? This paper attempts to explore this question with particular attention to two factors: external business uncertainty and internal organizational capabilities. This study investigated whether business uncertainty, organizational learning and lean production capabilities influenced the adoption and implementation of CMPs as well as examining how organizational capabilities moderate the relationships between business uncertainty and the level of CMPs. The results of a cross‐sectional survey and hierarchical regression analyses indicate that perceived business uncertainty decreases the adoption of CMPs, organizational learning and lean production capabilities strongly facilitate the adoption and implementation of CMPs, and lean production capability positively moderates the impacts of business uncertainty on the adoption of CMPs. This study provides guidance for managers and academics considering how to identify, design and manage the dimensions of a firm's practices in response to the global warming issue within the organization as well as with other organizations. Copyright © 2015 John Wiley & Sons, Ltd and ERP Environment
Protect department from infractions by taking note of lessons learned from Syracuse case
Authors: O'Brien Timothy
Published: May 2015

The decision issued by the National Collegiate Athletic Association's Division I Committee on Infractions involving Syracuse University serves as a timely warning of the importance of academic integrity, institutional control, and the responsibilities of a head coach.
Was coach wrongfully suspended for off‐campus conduct?
Authors: Gelpi Aileen
Published: May 2015

Mark Stapor was a graduate student at Wagner College. He also served as an assistant coach on one of its athletics teams.
Crystal Structure of Okadaic Acid Binding Protein 2.1: A Sponge Protein Implicated in Cytotoxin Accumulation
Authors: Ehara Haruhiko , Makino Marie , Kodama Koichiro , Konoki Keiichi , Ito Takuhiro , Sekine Shun‐ichi , Fukuzawa Seketsu , Yokoyama Shigeyuki , Tachibana Kazuo
Published: May 2015

Okadaic acid (OA) is a marine polyether cytotoxin that was first isolated from the marine sponge Halichondria okadai. OA is a potent inhibitor of protein serine/threonine phosphatases (PP) 1 and 2A, and the structural basis of phosphatase inhibition has been well investigated. However, the role and mechanism of OA retention in the marine sponge have remained elusive. We have solved the crystal structure of okadaic acid binding protein 2.1 (OABP2.1) isolated from H. okadai; it has strong affinity for OA and limited sequence homology to other proteins. The structure revealed that OABP2.1 consists of two α‐helical domains, with the OA molecule deeply buried inside the protein. In addition, the global fold of OABP2.1 was unexpectedly similar to that of aequorin, a jellyfish photoprotein. The presence of structural homologues suggested that, by using similar protein scaffolds, marine invertebrates have developed diverse survival systems adapted to their living environments.