bluuebunny/crossref_metadata_2025_split huggingface dataset:
Calibrating the magnitude of the Toarcian carbon cycle perturbation
Authors: Suan Guillaume , van de Schootbrugge Bas , Adatte Thierry , Fiebig Jens , Oschmann Wolfgang 
Published: April 2015

AbstractSedimentary rocks recording the Toarcian oceanic anoxic event (T‐OAE) are marked by a negative carbon isotope excursion (CIE) reaching up to −7‰ and ranking among the largest known in the Phanerozoic. These records suggest a dramatic perturbation of the carbon cycle that has been linked to the transfer of juvenile carbon from the endogenic to the exogenic reservoirs. Nevertheless, the magnitude of the Toarcian CIE varies significantly from one substrate to another, hence complicating mass balance evaluation of the potential driving mechanisms. Here we show, using high‐resolution, paired records of δ13Ctotal organic carbon (TOC) and hydrogen index from the Denkingen core and Dotternhausen quarry (Germany), that the amplitude of the negative CIE in marine organic matter is considerably exaggerated by changes in organic matter sourcing. Our corrected 3–4‰ CIE implies a constant carbon isotope fractionation between organic and carbonate carbon across the T‐OAE and may point to a prominent role of cyanobacteria as organic matter producers during the Early Jurassic. These results also suggest that the difference between inorganic and organic carbon isotope values in marine strata constitutes a poor proxy of pCO2 levels across the T‐OAE. Moreover, this corrected 3–4‰ CIE, together with evidence for >5°C seawater warming across the T‐OAE, point to the input of >25,000 Gt C with much more 13C‐enriched signature than previously modeled. Our results thus allow reconciling inorganic and organic δ13C records of the T‐OAE and have important implications for the evaluation of their causal mechanisms.
Modeling the release of E. coli D21g with transients in water content
Authors: Bradford Scott A. , Wang Yusong , Torkzaban Saeed , Šimůnek Jiri 
Published: April 2015

AbstractTransients in water content are well known to mobilize colloids that are retained in the vadose zone. However, there is no consensus on the proper model formulation to simulate colloid release during drainage and imbibition. We present a model that relates colloid release to changes in the air‐water interfacial area (Aaw) with transients in water content. Colloid release from the solid‐water interface (SWI) is modeled in two steps. First, a fraction of the colloids on the SWI partitions to the mobile aqueous phase and air‐water interface (AWI) when the Aaw increases during drainage. Second, colloids that are retained on the AWI or at the air‐water‐solid triple line are released during imbibition as the AWI is destroyed. The developed model was used to describe the release of Escherichia coli D21g during cycles of drainage and imbibition under various saturation conditions. Simulations provided a reasonable description of experimental D21g release results. Only two model parameters were optimized to the D21g release data: (i) the cell fraction that was released from the SWI (fr) and (ii) the cell fraction that partitioned from the SWI to the AWI (fawi). Numerical simulations indicated that cell release was proportional to fr and the initial amount of retention on the SWI and AWI. Drainage to a lower water content enhanced cell release, especially during subsequent imbibition, because more bacteria on the SWI were partitioned to the AWI and/or aqueous phase. Imbibition to a larger water content produced greater colloid release because of higher flow rates, and more destruction of the AWI (smaller Aaw). Variation in the value of fawi was found to have a pronounced influence on the amount of cell release in both drainage and imbibition due to changes in the partitioning of cells from the SWI to the aqueous phase and the AWI.
Devastation of aquifers from tsunami‐like storm surge by Supertyphoon Haiyan
Authors: Cardenas M. Bayani , Bennett Philip C. , Zamora Peter B. , Befus Kevin M. , Rodolfo Raymond S. , Cabria Hillel B. , Lapus Mark R. 
Published: April 2015

AbstractThe northwest Pacific Ocean is a hot spot for sea level rise and increasing frequency of stronger storms. It is where Supertyphoon Haiyan formed, the strongest storm to hit land, which provided a window into the hydrologic impacts of an extreme storm. Through detailed documentation of flood levels, groundwater table elevations and salinity, electrical resistivity, and modeling, we found that Haiyan's storm surge reached 7 m above sea level along Samar Island, Philippines, which led to contamination of crucial aquifers by infiltrating seawater. A contaminated surficial aquifer will take years to recover. Groundwater in an underlying deeper aquifer saw widespread contamination immediately after the storm, but here salinity has decreased significantly after 8 months. However, this deeper aquifer remains vulnerable to seawater slowly percolating through the surficial aquifer. As warmer seas generate more powerful storms, the vulnerability of aquifers to persistent contamination from intense storm surges is a growing concern for coastal communities.
Effects of temperature, pH, and ionic strength on the Henry's law constant of triethylamine
Authors: Leng Chun‐Bo , Roberts Jason E. , Zeng Guang , Zhang Yun‐Hong , Liu Yong 
Published: April 2015

AbstractThe Henry's law constants (KH) of triethylamine (TEA) in pure water and in 1‐octanol were measured for the temperatures pertinent to the lower troposphere (278–298 K) using a bubble column system coupled to a Fourier transform infrared spectrometer. The KH values of TEA in water and 1‐octanol at 298 K are 5.75 ± 0.86 mol L−1 atm−1 and 115.62 ± 5.78 mol L−1 atm−1. The KH values display strong dependence on temperature, pH, and ionic strength. The characteristic times for TEA to establish an equilibrium between gas and droplet with a size of 5.6 µm are ~33 s (298 K, pH = 5.6); ~8.9 × 102 s (278 K, pH = 5.6); ~1.3 × 103 s (298 K, pH = 4.0); and 3.6 × 104 s (278 K, pH = 4.0). The evaluation of TEA partitioning between gas phase and condensed phase implies that TEA predominantly resides in rainwater, and TEA loss to organic aerosol is negligible.
Altimeter‐derived seasonal circulation on the southwest Atlantic shelf: 27°–43°S
Authors: Strub P. Ted , James Corinne , Combes Vincent , Matano Ricardo P. , Piola Alberto R. , Palma Elbio D. , Saraceno Martin , Guerrero Raul A. , Fenco Harold , Ruiz‐Etcheverry Laura A. 
Published: April 2015

AbstractAltimeter sea surface height (SSH) fields are analyzed to define and discuss the seasonal circulation over the wide continental shelf in the SW Atlantic Ocean (27°–43°S) during 2001–2012. Seasonal variability is low south of the Rio de la Plata (RdlP), where winds and currents remain equatorward for most of the year. Winds and currents in the central and northern parts of our domain are also equatorward during autumn and winter but reverse to become poleward during spring and summer. Transports of shelf water to the deep ocean are strongest during summer offshore and to the southeast of the RdlP. Details of the flow are discussed using mean monthly seasonal cycles of winds, heights, and currents, along with analyses of Empirical Orthogonal Functions. Principle Estimator Patterns bring out the patterns of wind forcing and ocean response. The largest part of the seasonal variability in SSH signals is due to changes in the wind forcing (described above) and changes in the strong boundary currents that flow along the eastern boundary of the shelf. The rest of the variability contains a smaller component due to heating and expansion of the water column, concentrated in the southern part of the region next to the coast. Our results compare well to previous studies using in situ data and to results from realistic numerical models of the regional circulation.
Hyporheic zone hydrologic science: A historical account of its emergence and a prospectus
Authors: Cardenas M. Bayani 
Published: April 2015

AbstractThe hyporheic zone, defined by shallow subsurface pathways through river beds and banks beginning and ending at the river, is an integral and unique component of fluvial systems. It hosts myriad hydrologically controlled processes that are potentially coupled in complex ways. Understanding these processes and the connections between them is critical since these processes are not only important locally but integrate to impact increasingly larger scale biogeochemical functioning of the river corridor up to the river network scale. Thus, the hyporheic zone continues to be a growing research focus for many hydrologists for more than half the history of Water Resources Research. This manuscript partly summarizes the historical development of hyporheic zone hydrologic science as gleaned from papers published in Water Resources Research, from the birth of the concept of the hyporheic zone as a hydrologic black box (sometimes referred to as transient storage zone), to its adolescent years of being torn between occasionally competing research perspectives of interrogating the hyporheic zone from a surface or subsurface view, to its mature emergence as an interdisciplinary research field that employs the wide array of state‐of‐the‐art tools available to the modern hydrologist. The field is vibrant and moving in the right direction of addressing critical fundamental and applied questions with no clear end in sight in its growth. There are exciting opportunities for scientists that are able to tightly link the allied fields of geology, geomorphology, hydrology, geochemistry, and ecology to tackle the many open problems in hyporheic zone science.
ULSAS—Suspension, A Comparison of Rear Suspension Design
Authors: Wallentowitz Henning 
Published: April 2015

AbstractThe international steel industry ordered a research project to develop lightweight rear axle suspensions made out of steel only. The target was to reach 20% weight reduction without cost penalty, compared with existing steel concept, or to reach 20% cost reduction at the same weight, compared with aluminum suspensions.This research project delivered analysis of existing axles and corresponding proposals and fulfilled the requested conditions. In addition, many technical proposals to improve the axle design have been published. This research report is still a source of design ideas for future cars.
Active Front Steering for Passenger Cars
Authors: Wiedmann Matthias 
Published: April 2015

AbstractThe steering system is the major link between the driver and the road. In this function, it affects driving feel, safety, and comfort. In the past, there have been major improvements in the form of hydraulic power steering, variable‐assist power steering, and last but not least electronic power steering with its wide tuning range. To achieve a specific driving feel, the best way is to vary the steering torque as well as the steering angle. To vary the required steering angle, an angle superimposition system is needed. With such a system, further various functions have become possible, such as variable steering ratio and active steering stabilization.
Passive and Active Limited Slip Differentials
Authors: Palazzolo Joseph 
Published: April 2015

Abstract
Limited slip differentials (LSDs) were developed to overcome the deficiencies of an open differential in extreme vehicle conditions where traction was limited. The most common example is a slippery surface on one of the drive wheels with a nonslippery surface on the drive wheel. In this situation, the wheel on the slippery surface will spin, whereas the other wheel will provide very little assistance and the vehicle is basically unable to propel forward. There are many different styles and means of overcoming this condition. The LSDs can be broken into two main categories of active and passive types. The most common styles are reviewed along with the pertinent equations to predict and model their behavior.
Hardware‐in‐the‐Loop Simulation
Authors: Köhl Susanne , Plöger Markus 
Published: April 2015

AbstractIn the last 20 years, hardware‐in‐the‐loop (HIL) simulation has become an integral part of the electronic control unit (ECU) software development process for both original equipment manufacturers (OEMs) and suppliers. In many companies, successfulHILtests are even the precondition for system approval. At the present time, the main requirements forHILsimulation systems areversatility for different test tasks;flexibility duringHILtesting due to changing workflows;reduced time to market for newECUsoftware;management of increasing vehicle function complexity.This chapter introducesHILsimulation and describes its objectives, as well as the different roles involved. The hardware and software components (SWCs) ofHILsimulation are also presented, with an explanation on how to successfully integrateHILtests into the existing development process. The chapter concludes by looking at futureHILsimulation requirements.
Voltage Control and Frequency Control
Authors: Rehtanz Christian , Rolink Johannes , Horenkamp Willi 
Published: April 2015

Abstract

Electric vehicles (EVs) are nowadays treated as potential candidates for providing ancillary services. Owing to their storage capability, they are able to store energy in times of overproduction, especially from renewable energy sources, and to restore it, for example, when the volatile feed‐in is low. Thereby,
EVs
can help to maintain and improve the quality, reliability, and stability of the supply system. This means a paradigm shift because generally ancillary services are not provided from the low‐voltage grid. This chapter discusses these services and how electric vehicles can contribute to them. The main focus is on voltage and frequency control. For the analysis, the German perspective is chosen. First of all, voltage control is discussed briefly. This is followed by an overview of the current regulatory framework for providing frequency control in Germany. Eventually, a basic analysis of the technical potential of electric vehicles is presented taking into account the different types of control power.
Adaptive sensor and actuator fault estimation for a class of uncertain Lipschitz nonlinear systems
Authors: Defoort Michael , Veluvolu Kalyana C. , Rath Jagat J. , Djemai Mohamed 
Published: April 2015

SummaryThis paper deals with state and fault estimations for a class of uncertain Lipschitz nonlinear systems. The proposed scheme combines a descriptor form observer and an adaptive sliding mode observer. The adaptive descriptor sliding approach is proposed to jointly estimate the state and reconstruct the sensor fault while rejecting the effect of uncertainties and Lipschitz nonlinearities. Using a Lyapunov analysis, the stability condition is analyzed and the observer gains are designed such that the reduced–order system is practically stable. Then, an adaptive super‐twisting observer is derived to reconstruct the actuator faults. The main feature of the proposed adaptive scheme is that it does not overestimate the observer gains, which mitigates chattering in the presence of bounded uncertainties, actuator, and sensor faults with unknown boundaries. Simulation results for a robotic manipulator show the effectiveness of the proposed method. Copyright © 2015 John Wiley & Sons, Ltd.
Extreme Flexibility in a Zeolitic Imidazolate Framework: Porous to Dense Phase Transition in Desolvated ZIF‐4
Authors: Wharmby Michael T. , Henke Sebastian , Bennett Thomas D. , Bajpe Sneha R. , Schwedler Inke , Thompson Stephen P. , Gozzo Fabia , Simoncic Petra , Mellot‐Draznieks Caroline , Tao Haizheng , Yue Yuanzheng , Cheetham Anthony K. 
Published: April 2015

AbstractDesolvated zeolitic imidazolate framework ZIF‐4(Zn) undergoes a discontinuous porous to dense phase transition on cooling through 140 K, with a 23 % contraction in unit cell volume. The structure of the non‐porous, low temperature phase was determined from synchrotron X‐ray powder diffraction data and its density was found to be slightly less than that of the densest ZIF phase, ZIF‐zni. The mechanism of the phase transition involves a cooperative rotation of imidazolate linkers resulting in isotropic framework contraction and pore space minimization. DFT calculations established the energy of the new structure relative to those of the room temperature phase and ZIF‐zni, while DSC measurements indicate the entropic stabilization of the porous room temperature phase at temperatures above 140 K.
Acylsulfonamide‐Functionalized Zwitterionic Gold Nanoparticles for Enhanced Cellular Uptake at Tumor pH
Authors: Mizuhara Tsukasa , Saha Krishnendu , Moyano Daniel F. , Kim Chang Soo , Yan Bo , Kim Young‐Kwan , Rotello Vincent M. 
Published: April 2015

AbstractA nanoparticle design featuring pH‐responsive alkoxyphenyl acylsulfonamide ligands is reported herein. As a result of ligand structure, this nanoparticle is neutral at pH 7.4, becoming positively charged at tumor pH (<6.5). The particle uptake and cytotoxicity increase over this pH range. This pH‐controlled uptake and toxicity makes this particle a promising tool for tumor selective therapy.
Visible‐Light‐Mediated Chan–Lam Coupling Reactions of Aryl Boronic Acids and Aniline Derivatives
Authors: Yoo Woo‐Jin , Tsukamoto Tatsuhiro , Kobayashi Shū 
Published: April 2015

AbstractThe copper(II)‐catalyzed aerobic oxidative coupling reaction between aryl boronic acids and aniline derivatives was found to be improved significantly under visible‐light‐mediated photoredox catalysis. The substrate scope of this oxidative Chan–Lam reaction was thus expanded to include electron‐deficient aryl boronic acids as viable starting materials.
Targeted Histone Peptides: Insights into the Spatial Regulation of the Methyltransferase PRC2 by using a Surrogate of Heterotypic Chromatin
Authors: Brown Zachary Z. , Müller Manuel M. , Kong Ha Eun , Lewis Peter W. , Muir Tom W. 
Published: April 2015

AbstractEukaryotic genomes are dynamically regulated through a host of epigenetic stimuli. The substrate for these epigenetic transactions, chromatin, is a polymer of nucleosome building blocks. In native chromatin, each nucleosome can differ from its neighbors as a result of covalent modifications to both the DNA and the histone packaging proteins. The heterotypic nature of chromatin presents a formidable obstacle to biochemical studies seeking to understand the role of context on epigenetic regulation. A chemical approach to the production of heterotypic chromatin that can be used in such studies is introduced. This method involves the attachment of a user‐defined modified histone peptide to a designated nucleosome within the polymer by using a peptide nucleic acid (PNA) targeting compound. This strategy was applied to dissect the effect of chromatin context on the activity of the histone methyltransferase PRC2. The results show that PRC2 can be stimulated to produce histone H3 methylation from a defined nucleation site.
Sampling of Glycan‐Bound Conformers by the Anti‐HIV Lectin Oscillatoria agardhii agglutinin in the Absence of Sugar
Authors: Carneiro Marta G. , Koharudin Leonardus M. I. , Ban David , Sabo T. Michael , Trigo‐Mourino Pablo , Mazur Adam , Griesinger Christian , Gronenborn Angela M. , Lee Donghan 
Published: April 2015

AbstractLectins from different sources have been shown to interfere with HIV infection by binding to the sugars of viral‐envelope glycoproteins. Three‐dimensional atomic structures of a number of HIV‐inactivating lectins have been determined, both as free proteins and in glycan‐bound forms. However, details on the mechanism of recognition and binding to sugars are elusive. Herein we focus on the anti‐HIV lectin OAA from Oscillatoria agardhii: We show that in the absence of sugars in solution, both the sugar‐free and sugar‐bound protein conformations that were observed in the X‐ray crystal structures exist as conformational substates. Our results suggest that glycan recognition occurs by conformational selection within the ground state; this model differs from the popular “excited‐state” model. Our findings provide further insight into molecular recognition of the major receptor on the HIV virus by OAA. These details can potentially be used for the optimization and/or development of preventive anti‐HIV therapeutics.
Induction of Immunogenic Cell Death by Chemotherapeutic Platinum Complexes
Authors: Wong Daniel Yuan Qiang , Ong Wendy Wei Fang , Ang Wee Han 
Published: April 2015

AbstractThere is compelling evidence suggesting that the immune‐modulating effects of many conventional chemotherapeutics, including platinum‐based agents, play a crucial role in achieving clinical response. One way in which chemotherapeutics can engage a tumor‐specific immune response is by triggering an immunogenic mode of tumor cell death (ICD), which then acts as an “anticancer vaccine”. In spite of being a mainstay of chemotherapy, there has not been a systematic attempt to screen both existing and upcoming Pt agents for their ICD ability. A library of chemotherapeutically active Pt agents was evaluated in an in vitro phagocytosis assay, and no correlation between cytotoxicity and phagocytosis was observed. A PtII N‐heterocyclic carbene complex was found to display the characteristic hallmarks of a type II ICD inducer, namely focused oxidative endoplasmic reticulum (ER) stress, calreticulin exposure, and both HMGB1 and ATP release, and thus identified as the first small‐molecule immuno‐chemotherapeutic agent.
A Palladium(II)‐Catalyzed CH Activation Cascade Sequence for Polyheterocycle Formation
Authors: Cooper Stephen P. , Booker‐Milburn Kevin I. 
Published: April 2015

AbstractPolyheterocycles are found in many natural products and are useful moieties in functional materials and drug design. As part of a program towards the synthesis of Stemona alkaloids, a novel palladium(II)‐catalyzed CH activation strategy for the construction of such systems has been developed. Starting from simple 1,3‐dienyl‐substituted heterocycles, a large range of polycyclic systems containing pyrrole, indole, furan and thiophene moieties can be synthesized in a single step.
Photooxidizing Chromium Catalysts for Promoting Radical Cation Cycloadditions
Authors: Stevenson Susan M. , Shores Matthew P. , Ferreira Eric M. 
Published: April 2015

AbstractThe photooxidizing capabilities of selected CrIII complexes for promoting radical cation cycloadditions are described. These complexes have sufficiently long‐lived excited states to oxidize electron‐rich alkenes, thereby initiating [4+2] processes. These metal species augment the spectrum of catalysts explored in photoredox systems, as they feature unique properties that can result in differential reactivity from the more commonly employed ruthenium or iridium catalysts.
Rhodium(III)‐Catalyzed [3+2]/[5+2] Annulation of 4‐Aryl 1,2,3‐Triazoles with Internal Alkynes through Dual C(sp2)H Functionalization
Authors: Yang Yuan , Zhou Ming‐Bo , Ouyang Xuan‐Hui , Pi Rui , Song Ren‐Jie , Li Jin‐Heng 
Published: April 2015

AbstractA rhodium(III)‐catalyzed [3+2]/[5+2] annulation of 4‐aryl 1‐tosyl‐1,2,3‐triazoles with internal alkynes is presented. This transformation provides straightforward access to indeno[1,7‐cd]azepine architectures through a sequence involving the formation of a rhodium(III) azavinyl carbene, dual C(sp2)H functionalization, and [3+2]/[5+2] annulation.