bluuebunny/crossref_metadata_2025_split huggingface dataset:
A spatial Markov model for the evolution of the joint distribution of groundwater age, arrival time, and velocity in heterogeneous media
Authors: Massoudieh Arash , Dentz Marco , Alikhani Jamal 
Published: June 2017

AbstractThe evolution of the joint distribution of groundwater age, velocity, and arrival times based on a Markov model for the velocities of fluid particles in heterogeneous porous media has been quantified. An explicit evolution equation for the joint distribution of age, arrival time, and particle velocity is derived, which is equivalent to a continuous time random walk for age, velocity, and arrival time. The approach is fully parameterized by the correlation model and the distribution of groundwater flow velocities. The transition probability for subsequent particle velocities along streamlines is implemented by a Copula, which is an efficient method to generate a correlated velocity series with prescribed marginal distribution. We discuss different solution methods based on finite‐differences and random walk particle tracking. The latter is based on continuous time random walks, whose transition times are obtained kinematically from the flow velocities. Specifically, we discuss a renormalization scheme to accelerate the particle‐tracking simulations based on the definition of aggregate particle transitions while at the same time renormalizing velocity correlation. The impact of velocity correlation and velocity distribution on the evolution of age at different distances from the inlet plane is also studied. At distances of the order of the correlation length, persistent particle velocities give the same behavior as stochastic streamtube models. For velocity distributions which give rise to transition times with finite variance, the age distributions evolve toward an inverse Gaussian. For heavy‐tailed weighting times, they evolve toward stable distribution as the distance from the inlet increases.
Role of air‐water interfaces in colloid transport in porous media: A review
Authors: Flury Markus , Aramrak Surachet 
Published: June 2017

AbstractAir‐water interfaces play an important role in unsaturated porous media, giving rise to phenomena like capillarity. Less recognized and understood are interactions of colloids with the air‐water interface in porous media and the implications of these interactions for fate and transport of colloids. In this review, we discuss how colloids, both suspended in the aqueous phase and attached at pore walls, interact with air‐water interfaces in porous media. We discuss the theory of colloid/air‐water interface interactions, based on the different forces acting between colloids and the air‐water interface (DLVO, hydrophobic, capillary forces) and based on thermodynamic considerations (Gibbs free energy). Subsurface colloids are usually electrostatically repelled from the air‐water interface because most subsurface colloids and the air‐water are negatively charged. However, hydrophobic interactions can lead to attraction to the air‐water interface. When colloids are at the air‐water interface, capillary forces are usually dominant over other forces. Moving air‐water interfaces are effective in mobilizing and transporting colloids from surfaces. Thermodynamic considerations show that, for a colloid, the air‐water interface is the favored state as compared with the suspension phase, except for hydrophilic colloids in the nanometer size range. Experimental evidence indicates that colloid mobilization in soils often occurs through macropores, although matrix transport is also prevalent in absence of macropores. Moving air‐water interfaces, e.g., occurring during infiltration, imbibition, or drainage, have been shown to scour colloids from surfaces and translocate colloids. Colloids can also be pinned to surfaces by thin water films and capillary menisci at the air‐water‐solid interface line, causing colloid retention and immobilization. Air‐water interfaces thus can both mobilize or immobilize colloids in porous media, depending on hydrodynamics and colloid and surface chemistry.
Appreciation of peer reviewers for 2016
Authors: Montanari Alberto , Bahr Jean , Blöschl Günter , Cai Ximing , Mackay D. Scott , Michalak Anna , Rajaram Harihar , Sanchez‐Vila Xavier 
Published: June 2017

AbstractOn behalf of the journal, the American Geophysical Union, and the scientific community, the editors would like to sincerely thank those who reviewed manuscripts for Water Resources Research in 2016. Their time spent reading and commenting on manuscripts not only improves the manuscripts themselves but also increases the scientific rigor of future research in the field. Many of those listed below went above and beyond and reviewed three or more manuscripts for our journal, and those are indicated in italics. Together, they contributed 3674 individual reviews of manuscripts submitted to Water Resources Research for consideration, of which 562 were eventually published. Thank you again. We look forward to a 2017 of exciting advances in the field and communicating those advances to our community and to the broader public.
Pain and Mortality in Older Adults: The Influence of Pain Phenotype
Authors: Smith Diane , Wilkie Ross , Croft Peter , McBeth John 
Published: June 2017

ObjectiveModerate to severe chronic pain affects 1 in 5 adults. Pain may increase the risk of mortality, but the relationship is unclear. This study investigated whether mortality risk was influenced by pain phenotype, characterized by pain extent or pain impact on daily life.MethodsThe study population was drawn from 2 large population cohorts of adults ages ≥50 years, the English Longitudinal Study of Ageing (n = 6,324) and the North Staffordshire Osteoarthritis Project (n = 10,985). Survival analyses (Cox's proportional hazard models) estimated the risk of mortality in participants reporting any pain and then separately according to the extent of pain (total number of pain sites, widespread pain according to the American College of Rheumatology [ACR] criteria, and widespread pain according to Manchester criteria) and pain impact on daily life (pain interference and often troubled with pain). Models were cumulatively adjusted for age, sex, education, and wealth/adequacy of income.ResultsAfter adjustments, the report of any pain (mortality rate ratio [MRR] 1.06 [95% confidence interval (95% CI) 0.95–1.19]) or having widespread pain (ACR 1.07 [95% CI 0.92–1.23] or Manchester 1.16 [95% CI 0.99–1.36]) was not associated with an increased risk of mortality. Participants who were often troubled with pain (MRR 1.29 [95% CI 1.12–1.49]) and those who reported quite a bit of pain interference (MRR 1.38 [95% CI 1.20–1.59]) and extreme pain interference (MRR 1.88 [1.54–2.29]) had an increased risk of all‐cause mortality.ConclusionPain that interferes with daily life, rather than pain per se, was associated with an increased risk of mortality. Future studies should investigate the mechanisms through which pain increases mortality risk.
Neuro‐Nano Interfaces: Utilizing Nano‐Coatings and Nanoparticles to Enable Next‐Generation Electrophysiological Recording, Neural Stimulation, and Biochemical Modulation
Authors: Young Ashlyn T. , Cornwell Neil , Daniele Michael A. 
Published: June 2017

AbstractNeural interfaces provide a window into the workings of the nervous system—enabling both biosignal recording and modulation. Traditionally, neural interfaces have been restricted to implanted electrodes to record or modulate electrical activity of the nervous system. Although these electrode systems are both mechanically and operationally robust, they have limited utility due to the resultant macroscale damage from invasive implantation. For this reason, novel nanomaterials are being investigated to enable new strategies to chronically interact with the nervous system at both the cellular and network level. In this feature article, the use of nanomaterials to improve current electrophysiological interfaces, as well as enable new nano‐interfaces to modulate neural activity via alternative mechanisms, such as remote transduction of electromagnetic fields are explored. Specifically, this article will review the current use of nanoparticle coatings to enhance electrode function, then an analysis of the cutting‐edge, targeted nanoparticle technologies being utilized to interface with both the electrophysiological and biochemical behavior of the nervous system will be provided. Furthermore, an emerging, specialized‐use case for neural interfaces will be presented: the modulation of the blood‐brain barrier.
DOSY Analysis of Micromolar Analytes: Resolving Dilute Mixtures by SABRE Hyperpolarization
Authors: Reile Indrek , Aspers Ruud L. E. G. , Tyburn Jean‐Max , Kempf James G. , Feiters Martin C. , Rutjes Floris P. J. T. , Tessari Marco 
Published: June 2017

AbstractDOSY is an NMR spectroscopy technique that resolves resonances according to the analytes’ diffusion coefficients. It has found use in correlating NMR signals and estimating the number of components in mixtures. Applications of DOSY in dilute mixtures are, however, held back by excessively long measurement times. We demonstrate herein, how the enhanced NMR sensitivity provided by SABRE hyperpolarization allows DOSY analysis of low‐micromolar mixtures, thus reducing the concentration requirements by at least 100‐fold.
Ring‐opening polymerization of lactide, ε‐caprolactone and their copolymerization catalyzed by β‐diketiminate zinc complexes
Authors: Keram Maryam , Ma Haiyan 
Published: June 2017

A series of zinc silylamido complexes bearing non‐symmetric β‐diketiminate ligands were synthesized and structurally characterized. Ring‐opening polymerization (ROP) of rac‐lactide catalyzed by these zinc complexes afforded heterotactic polylactides at room temperature (Pr = 0.79 ~ 0.83 in THF). The steric and electronic characteristics of the ancillary ligands showed significant influence on the polymerization performance of the corresponding zinc complexes. All these zinc complexes also showed moderate activities toward the polymerization of ε‐caprolactone at ambient temperature in toluene, producing polycaprolactones (PCLs) with high molecular weights and moderate polydispersities. PCL‐b‐PLLA copolymers could be obtained via three different copolymerization strategies (one‐pot polymerization, and sequential addition of the two monomers in either order) by adopting complex 6 as the initiator through the adjustment of reaction temperatures. The diblock nature of the copolymers was confirmed by 13C NMR spectroscopy and DSC analysis.
Synthesis, characterization and biological properties of mixed ligand complexes of cobalt(II/III) valproate with 2,9‐dimethyl‐1,10‐phenanthroline and 1,10‐phenanthroline
Authors: Abu Shamma Amani , Abu Ali Hijazi , Kamel Shayma 
Published: June 2017

The synthesis of mononuclear cobalt(II/III) complexes with two different ligands (complex 2: [Co(valp)2(2,9‐dmp)] and complex 3: [Co(valp)2(H2O)(1,10‐phen)]) was investigated and the characterization of both complexes was achieved using IR, UV–Vis, and single crystal X‐ray diffraction. Using single crystal X‐ray diffraction, the crystal structure of each of the complexes was determined. Additionally, the biological activity of these complexes was studied in five gram‐positive and four gram‐negative bacterial strains. Whereas in all gram‐negative bacteria tested, cobalt valproate complexes did not show any anti‐bacterial activity, both complexes had effects on gram positive bacteria. Complex 2 demonstrated good anti‐bacterial activity against all gram‐positive bacteria with inhibition zone diameter (IZD) ranging between 15–28 mm. Complex 3 exhibited low inhibition activity against all gram‐positive bacteria except E. faecalis with IZD ranging between 11.3–13.7 mm. Moreover, as an indication of its uses as industrial catalyst, the rate of bis(p‐nitrophenyl) phosphate (BNPP) hydrolysis when catalyzed by these complexes was measured at different temperatures, concentrations and pH. Complex 2 proved to be a better catalyst to induce the hydrolysis of BNPP.
Potential of commodity chemicals to become bio‐based according to maximum yields and petrochemical prices
Authors: Straathof Adrie J. J. , Bampouli Ariana 
Published: June 2017

AbstractCarbohydrates are the prevailing biomass components available for bio‐based production. The most direct way to convert carbohydrates into commodity chemicals is by one‐step conversion at maximum theoretical yield, such as by anaerobic fermentation without side product formation. Considering these hypothetical yields and petrochemical prices in Europe in 2010–2014, a ranking of 58 commodity chemicals was made using a simple model with ethanol as a base case. It was concluded that base chemicals such as lower olefins and benzene‐toluene‐xylene (BTX) are too cheap and require too much carbohydrate to be produced competitively compared to bioethanol. However, more oxidized products that require multiple conversion steps in petrochemical production, such as adipic acid, acrylic acid, acrylate esters, and 1,4‐butanediol, can be produced competitively from carbohydrates if theoretical yields are approached and if processing is efficient. Instead of carbohydrate fermentation, hypothetical photochemical production from CO2 was also considered. Using again a simple model, the same commodity chemicals remained the most attractive ones. © 2017 The Authors. Biofuels, Bioproducts, and Biorefining published by Society of Chemical Industry and John Wiley & Sons, Ltd.
Zug‐Schub‐Interaktion von puzzleförmigen Verbunddübelleisten
Authors: Claßen Martin , Adam Viviane , Kueres Dominik , Hegger Josef 
Published: June 2017

AbstractIn vielen Verbundkonstruktionen sind die Verbundmittel zwischen Stahl und Beton weder einer reinen Schub‐ noch einer reinen Zugbeanspruchung ausgesetzt, sondern werden durch kombiniert angreifende Zug‐ und Schubkräfte belastet. Während das Tragverhalten von Kopfbolzendübeln unter kombinierten Lasten umfänglich erforscht wurde und anhand von Modellen zuverlässig beschrieben werden kann, ist die kombinierte Beanspruchung von Verbunddübelleisten bisher weitestgehend ungeklärt. Zum Nachweis von Verbunddübelleisten unter kombinierten Zug‐Schub‐Lasten reichen die vorhandenen Bemessungsansätze für den reinen Schub und den reinen Zug nicht aus. Vielmehr ist die Interaktion beider Beanspruchungen durch Modelle zu erfassen. Im vorliegenden Beitrag werden daher systematische Untersuchungen zur Zug‐Schub‐Interaktion von Verbunddübelleisten vorgestellt. Anhand von Versuchen in einem neu entwickelten Versuchsstand und FE‐Berechnungen wird das Tragverhalten von Verbunddübelleisten unter kombinierten Lasten analysiert und ein Modellansatz zur Beschreibung der Zug‐Schub‐Interaktion hergeleitet.
A switch‐off fluorescence probe towards Pb(II) and cu(II) ions based on a calix[4]pyrrole bearing amino‐quinoline group
Authors: Bhatt Keyur D. , Shah Hemangini D. , Panchal Manthan 
Published: June 2017

AbstractA new fluorescence receptor calix[4]pyrrole‐N‐(quinoline‐8‐yl) acetamide (CAMQ) containing a pyrrolic ring connected via the meso‐position was synthesized, purified and characterized by elemental analysis, NMR and mass spectroscopy. This compound was examined for its fluorescence properties towards different metal ions e.g. Ag(I), Hg(II), Co(II), Ca(II), Ni(II), Zn(II), Cr(II), Ba(II), Fe(II), Cu(II), Pb(II)and Mg(II) ions by spectrophotometry and spectrofluorometry. It was concluded that the compound (CAMQ) possessed significantly enhanced selectivity for Pb(II) and Cu(II) ions in dimethyl sulfoxide (DMSO) even at very low concentrations (1 μM). It exhibit ‘turn‐on’ fluorescence when exposed to Pb(II) and Cu(II) and did so in preference to other metal ions. The binding constants, stoichiometry and quantum yields have been determined. The quenching mechanism was assessed using the Stern–Volmer equation and was also discussed.
Deciphering the Nature of Enzymatic Modifications of Bacterial Cell Walls
Authors: Lee Mijoon , Hesek Dusan , Lastochkin Elena , Dik David A. , Boggess Bill , Mobashery Shahriar 
Published: June 2017

AbstractThe major constituent of bacterial cell walls is peptidoglycan, which, in its crosslinked form, is a polymer of considerable complexity that encases the entire bacterium. A functional cell wall is indispensable for survival of the organism. There are several dozen enzymes that assemble and disassemble the peptidoglycan dynamically within each bacterial generation. Understanding of the nature of these transformations is critical knowledge for these events. Octasaccharide peptidoglycans were prepared and studied with seven recombinant cell‐wall‐active enzymes (SltB1, MltB, RlpA, mutanolysin, AmpDh2, AmpDh3, and PBP5). With the use of highly sensitive mass spectrometry methods, we described the breadth of reactions that these enzymes catalyzed with peptidoglycan and shed light on the nature of the cell wall alteration performed by these enzymes. The enzymes exhibit broadly distinct preferences for their substrate peptidoglycans in the reactions that they catalyze.
Poly(ethyleneimine)‐tethered Ir Complex Catalyst Immobilized in Titanate Nanotubes for Hydrogenation of CO2 to Formic Acid
Authors: Kuwahara Yasutaka , Fujie Yuki , Yamashita Hiromi 
Published: June 2017

AbstractThe front cover artwork for Issue 11/2017 is provided by the Yamashita research group of the Division of Materials and Manufacturing Science, Graduate School of Engineering, Osaka University (Japan). The image shows the production of formic acid from CO2 and H2 by a ternary hybrid catalyst composed of Ir complex, poly(ethyleneimine) and titanate nanotubes (TNTs). See the Full Paper itself at https://doi.org/10.1002/cctc.201700508.
Remarkable Modulation of Self‐Assembly in Short γ‐Peptides by Neighboring Ions and Orthogonal H‐Bonding
Authors: Jadhav Sandip V. , Amabili Paolo , Stammler Hans‐Georg , Sewald Norbert 
Published: June 2017

AbstractGabapentin, an antiepileptic drug, is known to form stable helical structures in short peptides. Distinctly, we report on the newly synthesized γ‐analogue of gabapentin, that is, γ‐gabapentin (γ‐Gpn), which manifests β‐sheet character at molecular and nanofibrous hydrogels at the supramolecular level. We investigated the influence of proximally immobilized cationic amino acids (lysine and arginine) on the self‐assembly of backbone‐expanded tripeptide motif. Interestingly, arginine was found to be superior, both physically and mechanically, over lysine in driving hydrogelation. We have concluded that intrinsic and biochemically distinct properties of the guanidinium ion of arginine (compared to ammonium ion of lysine) have contributed towards this effect. Furthermore, similar to pyroglutamyl (pGlu) modified amyloid β peptides, N‐pGlu modification of our self‐assembling tripeptide motif exerts a dramatic influence on aggregation and exhibits enhanced β‐sheet character, accelerated self‐assembly kinetics, improved optical transparency and provides higher mechanical stiffness to the peptide hydrogel.
Highly Stable Three‐Dimensional Porous Nickel‐Iron Nitride Nanosheets for Full Water Splitting at High Current Densities
Authors: Yan Feng , Wang Yue , Li Kaiyue , Zhu Chunling , Gao Peng , Li Chunyan , Zhang Xitian , Chen Yujin 
Published: June 2017

AbstractA noble‐metal‐free and highly efficient bifunctional catalyst for overall water splitting is greatly desirable to generate clean and sustainable energy carriers such as hydrogen, but enormous challenges remain. Herein, porous interconnected iron‐nickel nitride nanosheets are designed and grown on carbon fiber cloth (FeNi‐N/CFC); combining a facile electrodeposition method and in situ nitriding process. The as‐synthesized FeNi‐N/CFC, with a low mass loading of 0.25 mg cm−2, exhibits excellent catalytic activities for both the oxygen evolution reaction (OER) with 20 mA cm−2 at an overpotential (η) of 232 mV and also the hydrogen evolution reaction (HER) with 10 mA cm−2 at η=106 mV. As a bifunctional electrocatalyst for overall water splitting FeNi‐N/CFC only requires a cell voltage of 1.55 V to drive a current density (j) of 10 mA cm−2 and shows robust long‐term durability at j>360 mA cm−2 with a negligible change in current density over 60 h; revealing its promising application in commercial electrolyzers.
Bicyclic Peptides as Next‐Generation Therapeutics
Authors: Rhodes Curran A. , Pei Dehua 
Published: June 2017

AbstractBicyclic peptides have greater conformational rigidity and metabolic stability than linear and monocyclic peptides and are capable of binding to challenging drug targets with antibody‐like affinity and specificity. Powerful combinatorial library technologies have recently been developed to rapidly synthesize and screen large bicyclic peptide libraries for ligands against enzymes, receptors, and protein–protein interaction targets. Bicyclic peptides have been developed as potential therapeutics against a wide range of diseases, drug targeting agents, imaging/diagnostic probes, and research tools. In this Minireview, we provide a summary of the recent progresses on the synthesis and applications of bicyclic peptides.
Amorphous Nickel‐Cobalt‐Borate Nanosheet Arrays for Efficient and Durable Water Oxidation Electrocatalysis under Near‐Neutral Conditions
Authors: Chen Lanlan , Ren Xiang , Teng Wanqing , Shi Pengfei 
Published: June 2017

AbstractElectrolytic hydrogen generation needs earth‐abundant oxygen evolution reaction electrocatalysts that perform efficiently at mild pH. Here, the development of amorphous nickel‐cobalt‐borate nanosheet arrays on macroporous nickel foam (NiCo‐Bi/NF) as a 3D catalyst electrode for high‐performance water oxidation in near‐neutral media is reported. To drive a current density of 10 mA cm−2, the resulting NiCo‐Bi/NF demands an overpotential of only 430 mV in 0.1 m potassium borate (K‐Bi, pH 9.2). Moreover, it also shows long‐term electrochemical durability with maintenance of catalytic activity for 20 h, achieving a high turnover frequency of 0.21 s−1 at an overpotential of 550 mV.
Barbier Continuous Flow Preparation and Reactions of Carbamoyllithiums for Nucleophilic Amidation
Authors: Ganiek Maximilian A. , Becker Matthias R. , Berionni Guillaume , Zipse Hendrik , Knochel Paul 
Published: June 2017

AbstractAn ambient temperature continuous flow method for nucleophilic amidation and thioamidation is described. Deprotonation of formamides by lithium diisopropylamine (LDA) affords carbamoyllithium intermediates that are quenched in situ with various electrophiles such as ketones, allyl bromides, Weinreb and morpholino amides. The nature of the reactive lithium intermediates and the thermodynamics of the metalation were further investigated by ab initio calculations and kinetic experiments.
Simplified, High Drug‐Loaded Formulations Containing Hydrochlorothiazide for Twin‐Screw Granulation
Authors: Meier Robin , Moll Klaus‐Peter , Krumme Markus , Kleinebudde Peter 
Published: June 2017

AbstractSimplified, high drug loaded formulations for use in twin‐screw granulation and tableting were introduced, using the plastically deforming drug ibuprofen. This concept was enlarged by application of hydrochlorothiazide, because opposed deformation behavior was expected to result in different product performances. In most instances the results differed. Critical quality attributes like granule size distribution, disintegration time, and tensile strength of tablets could be met. The study confirms the suitability of simplified formulation with differently behaving drugs for pharmaceutical product design in continuous manufacturing.