bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Response Time of Glacial Erosion
Authors: Herman Frédéric , Braun Jean , Deal Eric , Prasicek Günther 
Published: March 2018

There has been recent progress in the understanding of the evolution of Quaternary climate. Simultaneously, there have been improvements in the understanding of glacial erosion processes, with better parameter constraints. Despite this, there remains much debate about whether or not the observed cooling over the Quaternary has driven an increase in glacial erosion rates. Most studies agree that the erosional response to climate change must be transient; therefore, the time scale of the climatic change and the response time of glacial erosion must be accounted for. Here we analyze the equations governing glacial erosion in a steadily uplifting landscape with variable climatic forcing and derive expressions for two fundamental response time scales. The first time scale describes the response of the glacier and the second one the glacial erosion response. We find that glaciers have characteristic time scales of the order of 10 to 10,000 years, while the characteristic time scale for glacial erosion is of the order of a few tens of thousands to a few million years. We then use a numerical model to validate the approximations made to derive the analytical solutions. The solutions show that short period forcing is dampened by the glacier response time, and long period forcing (>1 Myr) may be dampened by erosional response of glaciers when the rock uplift rates are high. In most tectonic and climatic conditions, we expect to see the strongest response of glacial erosion to periodic climatic forcing corresponding to Plio‐Pleistocene climatic cycles. Finally, we use the numerical model to predict the response of glacial systems to the observed climatic forcing of the Quaternary, including, but not limited to, the Milankovich periods and the long‐term secular cooling trend. We conclude that an increase of glacial erosion in response to Quaternary cooling is physically plausible, and we show that the magnitude of the increase depends on rock uplift and ice accumulation rates.
Developing High‐Performance Lithium Metal Anode in Liquid Electrolytes: Challenges and Progress
Authors: Li Sa , Jiang Mengwen , Xie Yong , Xu Hui , Jia Junyao , Li Ju 
Published: March 2018

AbstractLithium metal anodes are potentially key for next‐generation energy‐dense batteries because of the extremely high capacity and the ultralow redox potential. However, notorious safety concerns of Li metal in liquid electrolytes have significantly retarded its commercialization: on one hand, lithium metal morphological instabilities (LMI) can cause cell shorting and even explosion; on the other hand, breaking of the grown Li arms induces the so‐called “dead Li”; furthermore, the continuous consumption of the liquid electrolyte and cycleable lithium also shortens cell life. The research community has been seeking new strategies to protect Li metal anodes and significant progress has been made in the last decade. Here, an overview of the fundamental understandings of solid electrolyte interphase (SEI) formation, conceptual models, and advanced real‐time characterizations of LMI are presented. Instructed by the conceptual models, strategies including increasing the donatable fluorine concentration (DFC) in liquid to enrich LiF component in SEI, increasing salt concentration (ionic strength) and sacrificial electrolyte additives, building artificial SEI to boost self‐healing of natural SEI, and 3D electrode frameworks to reduce current density and delay Sand's extinction are summarized. Practical challenges in competing with graphite and silicon anodes are outlined.
Reliable Synthesis of Large‐Area Monolayer WS2 Single Crystals, Films, and Heterostructures with Extraordinary Photoluminescence Induced by Water Intercalation
Authors: Zhang Qianhui , Lu Jianfeng , Wang Ziyu , Dai Zhigao , Zhang Yupeng , Huang Fuzhi , Bao Qiaoliang , Duan Wenhui , Fuhrer Michael S. , Zheng Changxi 
Published: March 2018

AbstractTwo‐dimensional transition metal dichalcogenides (TMDs) hold great potential for future low‐energy optoelectronics owing to their unique electronic, optical, and mechanical properties. Chemical vapor deposition (CVD) is the technique widely used for the synthesis of large‐area TMDs. However, due to high sensitivity to the growth environment, reliable synthesis of monolayer TMDs via CVD remains challenging. Here a controllable CVD process is developed for large‐area synthesis of monolayer WS2 crystals, films, and in‐plane graphene–WS2 heterostructures by cleaning the reaction tube with hydrochloric acid, sulfuric acid, and aqua regia. The concise cleaning process can remove the residual contaminates attached to the CVD reaction tube and crucibles, reducing the nucleation density but enhancing the diffusion length of WS2 species. The photoluminescence (PL) mappings of a WS2 single crystal and film reveal that the extraordinary PL around the edges of a triangular single crystal is induced by ambient water intercalation at the WS2–sapphire interface. The extraordinary PL can be controlled by the choice of substrates with different wettabilities.
Effect of Si3N4‐Mediated Inversion Layer on the Electroluminescence Properties of Silicon Nanocrystal Superlattices
Authors: López‐Vidrier Julian , Gutsch Sebastian , Blázquez Oriol , Valenta Jan , Hiller Daniel , Laube Jan , Blanco‐Portals Javier , López‐Conesa Lluís , Estradé Sònia , Peiró Francesca , Garrido Blas , Hernández Sergi , Zacharias Margit 
Published: March 2018

AbstractThe achievement of an efficient all‐Si electrically‐pumped light emitter is a major milestone in present optoelectronics still to be fulfilled. Silicon nanocrystals (Si NCs) are an attractive material which, by means of the quantum confinement effect, allow attaining engineered bandgap visible emission from Si by controlling the NC size. In this work, SiO2‐embedded Si NCs are employed as an active layer within a light‐emitting device structure. It is demonstrated that the use of an additional thin Si3N4 interlayer within the metal–insulator–semiconductor device design induces an enhanced minority carrier injection from the substrate, which in turn increases the efficiency of sequential carrier injection under pulsed electrical excitation. This results in a substantial increase in the electroluminescence efficiency of the device. Here, the effect of this Si3N4 interlayer on the structural, optical, electrical, and electro‐optical properties of a Si NC‐based light emitter is reported, and the physics underlying these results is discussed.
Hohe elektromagnetische Feldverstärkung in nanotubularen TiO2‐Elektroden
Authors: Öner Ibrahim Halil , Querebillo Christine Joy , David Christin , Gernert Ulrich , Walter Carsten , Driess Matthias , Leimkühler Silke , Ly Khoa Hoang , Weidinger Inez M. 
Published: March 2018

AbstractWir präsentieren die Herstellung von TiO2‐Nanoröhren‐Elektroden mit hoher Biokompatibilität und außergewöhnlichen spektroskopischen Eigenschaften. Intensive oberflächenverstärkte Resonanz‐Raman‐Signale der Häm‐Gruppe des kovalent an die Elektrodenoberfläche immobilisierten Redox‐Enzyms Cytochrom b5 wurden beobachtet, die auf konservierte Proteinstruktur und Redox‐Eigenschaften schließen lassen. Der Verstärkungsfaktor konnte selektiv über die Kalzinierungstemperatur kontrolliert werden, wobei ein Rekordwert von über 70 bei einer Temperatur von 475 °C gefunden wurde. Zum ersten Mal konnten damit solche hohen Werte für eine nicht direkt oberflächengebundene Probe erreicht werden, bei der chemische Verstärkungseffekte ausgeschlossen werden können. Damit sind die hohen Verstärkungsfaktoren ausschließlich auf lokalisierte elektrische Felder zurückzuführen, hervorgerufen durch die spezifischen optischen Eigenschaften der nanotubularen Geometrie der Elektroden.
Monitoring social behaviour as an assessment of translocation success in a reintroduced population of the endangered Leon Springs pupfish (Cyprinodon bovinus)
Authors: Al‐Shaer Layla , Bloch Andrew , Little Kimberly , Itzkowitz M. 
Published: March 2018

Abstract

Translocation of endangered species from captivity into the wild is a common conservation practice used to bolster populations, expand natural ranges, and restore species that have been extirpated.
Often little is known of the fate of organisms after they are released, and extended monitoring of reintroduced populations is necessary for understanding the efficacy of this method.
Thought to have become extinct, the endangered Leon Springs pupfish (Cyprinodon bovinus) was rediscovered in 1965. Recently, conservation efforts have focused on renovating their natural habitat and reintroducing C. bovinus from a captive colony established in 1976 back into the ancestral habitat.
A reintroduction was performed in 2015, and the population was monitored over the next 14 months to ascertain whether territorial males were behaving typically for the species, and whether there were any changes in social behaviour over time.
An established population in nearby Diamond Y Spring was used as a benchmark for typical social behaviour, and as an indicator for any expected seasonal differences in behaviour.
The development of a typical social system at Monsanto Deep Pool was evident almost immediately, as males started to establish breeding territories, defend them from intruders, and participate in reproductive activities, such as courtship and spawning. The presence of juveniles within a year indicated that individuals were successfully reproducing.
It appears that the translocated C. bovinus are developing into a stable and reproductively successful population.
Expedient Construction of the Hexacycle of Franchetine
Authors: Lv Zhengchao , Gao Lingzhi , Cheng Chuanxu , Niu Wei , Wang Jian‐Li , Xu Liang 
Published: March 2018

AbstractFranchetine, a unique 7,17‐seco type of norditerpenoid alkaloid, possesses a highly congested polycyclic architecture coupled with nine stereogenic centers. Here we present an efficient synthetic approach for the intact hexacyclic framework of franchetine from the known tricyle 16 in 20 steps. The synthesis features a diastereoselective 6‐exo‐tet radical cyclization for construction of ring A and a unique oxidative Wagner–Meerwein‐type rearrangement to realize the functionalized [3.2.1] bridging ring CD.
Active Disturbance Rejection Control for Teleoperation Systems with Actuator Saturation
Authors: Zhao Ling , Liu Lei , Wang Yingjie , Yang Hongjiu 
Published: March 2018

AbstractIn this paper, stabilization of a nonlinear bilateral teleoperation system with time delays and actuator saturation is investigated via active disturbance rejection control (ADRC). An linear extended state observer is introduced to deal with the lumped system uncertainties. Lyapunov functions are given to prove the stabilization of the closed‐loop bilateral teleoperation system. Two Phantom Premium 1.5 HighForce (HF) robot manipulators are used in experiments to demonstrate the effectiveness of the proposed method in this paper.
A GIS‐based spatial index of feedstock‐mixture availability for anaerobic co‐digestion of Mediterranean by‐products and agricultural residues
Authors: Valenti Francesca , Liao Wei , Porto Simona MC 
Published: March 2018

AbstractBiogas obtained from the anaerobic digestion of biomasses has increasingly been considered a feasible alternative to energy production from fossil fuel because of the possible advantages derived from both the reduction of the environmental burden and the reuse of by‐products and agricultural residues. Italy is the third largest biogas producer in the world after China and Germany, but the biogas sector in southern Italy, especially in Sicily, is still developing.The objective of this study was to contribute to the sustainable development of the biogas sector in Sicily by developing a method for the localization of geographical areas suitable for biogas production. First, a feedstock mixture found in previous research studies (which investigated several mixes of main agricultural residues and by‐products available in Sicily for the enhancement of biogas production in terms of methane content) was used to evaluate each feedstock territorial distribution in a study area. Then a GIS‐based model for the computation of a spatial index of feedstock‐mixture availability, ifm_a , was developed. The computed spatial index was applied on a GIS map to investigate the availability of the feedstock mixture in the area under study.The results of the territorial analyses obtained by applying the index showed the geographical areas suitable for the development of new biogas plants. The results of this study could be helpful in reducing the significant transport costs of each feedstock as well as the environmental impact of biogas production. In this regard, the results are in line with the policy priorities of the Europe 2020 strategy, which aims to valorize by‐products and agricultural residues through their reuse. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd
Production of 1,3‐butadiene and ε‐caprolactam from C6 sugars: Techno‐economic analysis
Authors: Moncada Jonathan , Gursel Iris Vural , Worrell Ernst , Ramírez Andrea 
Published: March 2018

AbstractThis study assesses the techno‐economic performance of production lines for obtaining 1,3‐butadiene and ε‐caprolactam from C6 sugars. Process models were developed to assess their technical performance and to derive inputs for economic analysis. The economic assessment was carried out using net present value (NPV) and production costs as indicators. Sensitivity analyses were carried out to account for the effects of variations in inputs, such as processing capacity, valorization of humins, and prices, on the economic outputs. Results indicate that both production lines perform similarly from an energy intensity point of view (34–50 MJ/kg of main product). However, in terms of yield (kg of product per kg C6 sugar), caprolactam shows higher values by a factor of 1.6–3.6 in comparison to that of butadiene. The butadiene production line is not economically attractive, showing a negative NPV (−647 to −642 M€) and production costs 3–5 times higher than the reference market price (Case I 4369 €/tonne, Case II 3406 €/tonne). The caprolactam production line seems to be unfeasible with negative NPV (−229 M€) and production costs 30% higher than the reference price (Case III 2595 €/tonne, Case IV 1875 €/tonne). However, if the production yield is increased, the caprolactam production line becomes economically attractive with production costs 6% lower than its reference market price. The production costs of caprolactam can be further decreased if the process capacity is increased, reflecting the benefits of the economies of scale, as well as including heat and power produced from humins. Overall, the caprolactam production line shows higher economic potential. © 2018 Society of Chemical Industry and John Wiley & Sons, Ltd
Thermodynamics of the pseudo‐knot in helix 18 of 16S ribosomal RNA
Authors: Wojciechowska Monika , Dudek Marta , Trylska Joanna 
Published: March 2018

AbstractA fragment of E. coli 16S rRNA formed by nucleotides 500 to 545 is termed helix 18. Nucleotides 505‐507 and 524‐526 form a pseudo‐knot and its distortion affects ribosome function. Helix 18 isolated from the ribosome context is thus an interesting fragment to investigate the structural properties and folding of RNA with pseudo‐knots. With all‐atom molecular dynamics simulations, spectroscopic and gel electrophoresis experiments, we investigated thermodynamics of helix 18, with a focus on its pseudo‐knot. In solution studies at ambient conditions we observed dimerization of helix 18. We proposed that the loop, containing nucleotides forming the pseudo‐knot, interacts with another monomer of helix 18. The native dimer is difficult to break but introducing mutations in the pseudo‐knot indeed assured a monomeric form of helix 18. Molecular dynamics simulations at 310 K confirmed the stability of the pseudo‐knot but at elevated temperatures this pseudo‐knot was the first part of helix 18 to lose the hydrogen bond pattern. To further determine helix 18 stability, we analyzed the interactions of helix 18 with short oligomers complementary to a nucleotide stretch containing the pseudo‐knot. The formation of higher‐order structures by helix 18 impacts hybridization efficiency of peptide nucleic acid and 2'‐O methyl RNA oligomers.
Living a meaningful life with chronic pain – further follow‐up
Authors: Dysvik Elin , Furnes Bodil 
Published: March 2018

Key Clinical MessageLiving a meaningful life with chronic pain seems to depend on the patient having the leading role in their own life. Adequate assistance from healthcare professionals should be balanced during changing circumstances. Successful follow‐up demands an independent biopsychosocial–spiritual–existential perspective, where patient‐centered care and a focus on resilience go together.
Optimization of Ellagic Acid Purification from Pomegranate Husk by Antisolvent Recrystallization
Authors: Wang Li , Lian Bolin , Wu Weiwei , Deng Yiping , Liu Yanjie , Wang Lingling , Li Yuanyuan , Wang Zijian , Zhao Xiuhua 
Published: March 2018

AbstractEllagic acid (EA) was produced from pomegranate husk by extraction of tannins followed by acid hydrolysis and purified by antisolvent recrystallization. Response surface methodology, based on a five‐level, four‐variable central composite design, was employed to find the optimum purification conditions. Under these conditions, high purity and yield of EA was obtained in close agreement with the predicted values by the model. Analyzes of surface morphology and in vitro percutaneous absorption experiments of EA let conclude that the granule morphology of the purified EA was significantly different from the crude EA, and its particle size was much smaller than that of the crude EA. Evaluation in vitro demonstrated that the permeation rate of the purified EA was higher compared with the crude EA.
Poly(vinylidene fluoride)‐Based Membranes for Microalgae Filtration
Authors: Marbelia Lisendra , Bilad Muhammad R. , Maes Sarah , Arafat Hassan A. , Vankelecom Ivo F. J. 
Published: March 2018

AbstractTwo poly(vinylidene fluoride) (PVDF) membrane modification approaches, i.e., poly(vinylpyrrolidone) (PVP) modification and sulfonation, were applied and investigated to produce a fouling‐resistant membrane for microalgae filtration. Both methods were able to alter the membrane surface to become more hydrophilic. However, clean water permeance increased only for the PVP‐modified membranes, while the sulfonated membranes underwent a significant morphology transformation to a denser membrane and thus lower permeance. Microalgae filtration with PVP‐modified membranes showed less fouling compared to the pristine one, particularly in the beginning of the filtration, indicating that fouling reduction on these membranes mainly occurs in the initial fouling stage. Fouling is also found to be influenced by the microalgae species, possibly due to the different properties of the formed cake layer.
Adhesion Moment of a Particle on a Wall in Gaseous Environment
Authors: Haarmann Alexander , Schmidt Eberhard 
Published: March 2018

AbstractIf a particle adheres to a wall, it gets flattened. When such a particle gets stressed sideways by an external force, it will start to roll. To get the particle into a rolling motion, a resistive moment must be overcome, the so‐called adhesion moment. An experimental setup was designed to measure the force which must be applied to an adhered particle to trigger a rolling motion in the specimen chamber of an environmental scanning electron microscope (ESEM). From this force, the adhesion moment can be calculated. A detailed explanation of the experiments will be given. The results of the experiments are discussed.
Hydrogen Bonding Effects on the Reversible Reorganization of Organic Films Electrografted on Glassy Carbon Electrodes
Authors: Morales‐Martínez Daniel , González Felipe J. 
Published: March 2018

AbstractThe electrochemical oxidation of tetrabutylammonium carboxylates derived from 6‐oxoheptanoic acid and 6‐heptynoic acid was performed on glassy carbon electrodes to generate covalently modified electrodes bearing alkyl‐ketone and alkynyl groups. These surfaces were used as models of hydrogen‐bond‐accepting surfaces to study the interaction of water with the grafted film; 1,4‐benzoquinone was used as the redox probe to demonstrate the existence of these interactions. The voltammetric behavior of this redox probe on the modified electrode changed during cycling. However, leaving this electrode to stand in the electrolyte solution allows the recovery of the starting voltammogram. These changes observed between cycling and stand time are cyclical and can be explained through a reversible reorganization effect of the grafted film, which is attributed to hydrogen bonding interactions between the functional groups present in the structure film and water present in the solvent. Supporting these surface effects, the switching behavior was absent on hydrophobic films formed with saturated aliphatic chains or by using ferrocene as non‐hydrogen bonding redox probe.
On the Antibacterial Activity of Azacarboxylate Ligands: Lowered Metal Ion Affinities for Bis‐amide Derivatives of EDTA do not mean Reduced Activity
Authors: Mulla Raminder S. , Beecroft Marikka S. , Pal Robert , Aguilar Juan A. , Pitarch‐Jarque Javier , García‐España Enrique , Lurie‐Luke Elena , Sharples Gary J. , Gareth Williams J. A. 
Published: March 2018

AbstractEDTA is widely used as an inhibitor of bacterial growth, affecting the uptake and control of metal ions by microorganisms. We describe the synthesis and characterisation of two symmetrical bis‐amide derivatives of EDTA, featuring glycyl or pyridyl substituents: AmGly2 and AmPy2. Metal ion affinities (logK) have been evaluated for a range of metals (Mg2+, Ca2+, Fe3+, Mn2+, Zn2+), revealing less avid binding compared to EDTA. The solid‐state structures of AmGly2 and of its Mg2+ complex have been determined crystallographically. The latter shows an unusual 7‐coordinate, capped octahedral Mg2+ centre. The antibacterial activities of the two ligands and of EDTA have been evaluated against a range of health‐relevant bacterial species, three Gram negative (Escherichia coli, Pseudomonas aeruginosa and Klebsiella pneumoniae) and a Gram positive (Staphylococcus aureus). The AmPy2 ligand is the only one that displays a significant inhibitory effect against K. pneumoniae, but is less effective against the other organisms. AmGly2 exhibits a more powerful inhibitory effect against E. coli at lower concentrations than EDTA (<3 mm) or AmPy2, but loses its efficacy at higher concentrations. The growth inhibition of EDTA and AmGly2 on mutant E. coli strains with defects in outer‐membrane lipopolysaccharide (LPS) structures has been assessed to provide insight into the unexpected behaviour. Taken together, the results contradict the assumption of a simple link between metal ion affinity and antimicrobial efficacy.