bluuebunny/crossref_metadata_2025_split huggingface dataset:
Evaluation of entrainment formulations for liquid/gas plumes from underwater blowouts
Authors: F. Tessarolo Luciana , Innocentini Valdir 
Published: July 2016

AbstractA numerical model using the Lagrangian approach developed to simulate the fate of liquid/gas blowouts in deepwater is presented, and three entrainment formulations are tested: HOULT, JETLAG, and CORJET parameterizations, given by Hoult et al. (1969), Lee and Cheung (1990), and Jirka (2004), respectively. The results are discussed and compared with field and laboratory observations. These formulations differ both in shear and forced contributions to the entrainment. As expected, the qualitative analysis of the dynamics of a liquid plume shows that the entrainment of ambient water decreases the acceleration due to buoyancy, and the plume and ambient momentums become increasingly similar over time. However, simulations of field and laboratory cases, where different plumes (gas, liquid, and gas/liquid) were discharged into environments with different ambient stratifications and crossflows, show that the JETLAG parameterization provides the best results, while HOULT (CORJET) overestimates (underestimates) the entrainment. Additional numerical experiments applying only the JETLAG formulation are performed, considering different plume composition, ambient condition, nozzle diameter, and initial discharge. For all the studied cases, the simulated results are in good agreement with the observations. Especially noteworthy were field experiments with gas released at depth of 50–60 m. The vertical plume velocity decreased during the ascending motion, but after a certain level, the velocity increased. This feature was simulated by the JETLAG parameterization, and a closer analysis reveals the increase of buoyancy due to gas expansion exceeding the decrease caused by the entrainment. These results encourage the use of this model in realistic and complex situations.
High resolution modeling of dense water formation in the north‐western Mediterranean during winter 2012–2013: Processes and budget
Authors: Estournel Claude , Testor Pierre , Damien Pierre , D'Ortenzio Fabrizio , Marsaleix Patrick , Conan Pascal , Kessouri Faycal , Durrieu de Madron Xavier , Coppola Laurent , Lellouche Jean‐Michel , Belamari Sophie , Mortier Laurent , Ulses Caroline , Bouin Marie‐Noelle , Prieur Louis 
Published: July 2016

AbstractThe evolution of the stratification of the north‐western Mediterranean between summer 2012 and the end of winter 2013 was simulated and compared with different sets of observations. A summer cruise and profiler observations were used to improve the initial conditions of the simulation. This improvement was crucial to simulate winter convection. Variations of some parameters involved in air ‐ sea exchanges (wind, coefficient of transfer used in the latent heat flux formulation, and constant additive heat flux) showed that the characteristics of water masses and the volume of dense water formed during convection cannot be simply related to the time‐integrated buoyancy budget over the autumn ‐ winter period. The volume of dense water formed in winter was estimated to be about 50,000 km3 with a density anomaly larger than 29.113 kg m−3. The effect of advection and air/sea fluxes on the heat and salt budget of the convection zone was quantified during the preconditioning phase and the mixing period. Destratification of the surface layer in autumn occurs through an interaction of surface and Ekman buoyancy fluxes associated with displacements of the North Balearic front bounding the convection zone to the south. During winter convection, advection stratifies the convection zone: from December to March, the absolute value of advection represents 58 % of the effect of surface buoyancy fluxes.
Air‐water gas exchange by waving vegetation stems
Authors: Foster‐Martinez M. R. , Variano E. A. 
Published: July 2016

AbstractExchange between wetland surface water and the atmosphere is driven by a variety of motions, ranging from rainfall impact to thermal convection and animal locomotion. Here we examine the effect of wind‐driven vegetation movement. Wind causes the stems of emergent vegetation to wave back and forth, stirring the water column and facilitating air‐water exchange. To understand the magnitude of this effect, a gas transfer velocity (k600 value) was measured via laboratory experiments. Vegetation waving was studied in isolation by mechanically forcing a model canopy to oscillate at a range of frequencies and amplitudes matching those found in the field. The results show that stirring due to vegetation waving produces k600 values from 0.55 cm/h to 1.60 cm/h. The dependence of k600 on waving amplitude and frequency are evident from the laboratory data. These results indicate that vegetation waving has a nonnegligible effect on gas transport; thus, it can contribute to a mechanistic understanding of the fluxes underpinning biogeochemical processes.
Comment on “Advective transport in heterogeneous aquifers: Are proxy models predictive?” by A. Fiori, A. Zarlenga, H. Gotovac, I. Jankovic, E. Volpi, V. Cvetkovic, and G. Dagan
Authors: Neuman Shlomo P. 
Published: July 2016

AbstractFiori et al. (2015) examine the predictive capabilities of (among others) two “proxy” non‐Fickian transport models, MRMT (Multi‐Rate Mass Transfer) and CTRW (Continuous‐Time Random Walk). In particular, they compare proxy model predictions of mean breakthrough curves (BTCs) at a sequence of control planes with near‐ergodic BTCs generated through two‐ and three‐dimensional simulations of nonreactive, mean‐uniform advective transport in single realizations of stationary, randomly heterogeneous porous media. The authors find fitted proxy model parameters to be nonunique and devoid of clear physical meaning. This notwithstanding, they conclude optimistically that “i. Fitting the proxy models to match the BTC at [one control plane] automatically ensures prediction at downstream control planes [and thus] ii. … the measured BTC can be used directly for prediction, with no need to use models underlain by fitting.” I show that (a) the authors' findings follow directly from (and thus confirm) theoretical considerations discussed earlier by Neuman and Tartakovsky (2009), which (b) additionally demonstrate that proxy models will lack similar predictive capabilities under more realistic, non‐Markovian flow and transport conditions that prevail under flow through nonstationary (e.g., multiscale) media in the presence of boundaries and/or nonuniformly distributed sources, and/or when flow/transport are conditioned on measurements.
Efficient synthesis of iron nanoparticles by self‐agglomeration in a fluidized bed
Authors: Li Jun , Kong Jing , Zhu Qingshan , Li Hongzhong 
Published: July 2016

A two‐stage, fluidized reduction route is proposed to synthesize iron nanoparticles (NPs), with the aim of enhancing the quality of fluidization and preventing sintering activity. At both low and high temperatures, the degree of metallization η is approximately 80% due to the defluidization. Defluidization is mainly caused by the rapid sintering of the newly formed Fe NPs. The proposed two‐stage fluidization approach successfully resolves the defluidization problem through the self‐agglomeration of nanoparticles cultivated at low temperatures. These self‐agglomerated NPs showed an improved resistance to sintering at high temperatures. The high‐purity Fe NPs prepared by this approach exhibited excellent combustion activity, indicative of the potential as oxygen carriers in chemical looping combustion systems. © 2016 American Institute of Chemical Engineers AIChE J, 63: 459–468, 2017
Neutrale Dibor‐Analoga von archetypischen aromatischen Verbindungen durch spontane Cycloaddition
Authors: Arrowsmith Merle , Böhnke Julian , Braunschweig Holger , Celik Mehmet Ali , Claes Christina , Ewing William C. , Krummenacher Ivo , Lubitz Katharina , Schneider Christoph 
Published: July 2016

AbstractUnter der Vielzahl an Methoden, die Organiker zur Synthese von Benzolderivaten und Heteroarenen entwickelt haben, stellt die übergangsmetallkatalysierte Cycloaddition die eleganteste dar. Dagegen laufen Cycloadditionen mit schweren Alken‐ und Alkin‐Analoga, wenn auch in ihrem Umfang beschränkt, unkatalysiert ab. Hier stellen wir die ersten Cycloadditionen von leichten Alken‐ und Alkin‐Analoga vor, die spontan verlaufen. Die selektive Addition von unaktivierten Alkinen an Bor‐Bor‐Mehrfachbindungen führt unter normalen Bedingungen zu Dibor‐Kohlenstoff‐Äquivalenten von einfachen aromatischen Kohlenwasserstoffen, einschließlich der ersten neutralen, 6 π‐aromatischen Diborabenzol‐Verbindung, einem 2 π‐aromatischen, biradikalischen Triplett‐1,3‐Diboret und einem Phosphan‐stabilisierten 2 π‐homoaromatischen 1,3‐Dihydro‐1,3‐Diboret. Aufgrund der Ähnlichkeit der Grenzorbitale mit analogen aromatischen (C6H6 und C4H42+) und homoaromatischen (C4H5+) Kohlenwasserstoffen deuten DFT‐Rechnungen darauf hin, dass alle drei Verbindungen aromatisch sind.
Neutral Diboron Analogues of Archetypal Aromatic Species by Spontaneous Cycloaddition
Authors: Arrowsmith Merle , Böhnke Julian , Braunschweig Holger , Celik Mehmet Ali , Claes Christina , Ewing William C. , Krummenacher Ivo , Lubitz Katharina , Schneider Christoph 
Published: July 2016

AbstractAmong the numerous routes organic chemists have developed to synthesize benzene derivatives and heteroaromatic compounds, transition‐metal‐catalyzed cycloaddition reactions are the most elegant. In contrast, cycloaddition reactions of heavier alkene and alkyne analogues, though limited in scope, proceed uncatalyzed. In this work we present the first spontaneous cycloaddition reactions of lighter alkene and alkyne analogues. Selective addition of unactivated alkynes to boron–boron multiple bonds under ambient conditions yielded diborocarbon equivalents of simple aromatic hydrocarbons, including the first neutral 6 π‐aromatic diborabenzene compound, a 2 π‐aromatic triplet biradical 1,3‐diborete, and a phosphine‐stabilized 2 π‐homoaromatic 1,3‐dihydro‐1,3‐diborete. DFT calculations suggest that all three compounds are aromatic and show frontier molecular orbitals matching those of the related aromatic hydrocarbons, C6H6 and C4H42+, and homoaromatic C4H5+.
The Hydrated Excess Proton in the Zundel Cation H5O2+: The Role of Ultrafast Solvent Fluctuations
Authors: Dahms Fabian , Costard Rene , Pines Ehud , Fingerhut Benjamin P. , Nibbering Erik T. J. , Elsaesser Thomas 
Published: July 2016

AbstractThe nature of the excess proton in liquid water has remained elusive after decades of extensive research. In view of ultrafast structural fluctuations of bulk water scrambling the structural motifs of excess protons in water, we selectively probe prototypical protonated water solvates in acetonitrile on the femtosecond time scale. Focusing on the Zundel cation H5O2+ prepared in room‐temperature acetonitrile, we unravel the distinct character of its vibrational absorption continuum and separate it from OH stretching and bending excitations in transient pump‐probe spectra. The infrared absorption continuum originates from a strong ultrafast frequency modulation of the H+ transfer vibration and its combination and overtones. Vibrational lifetimes of H5O2+ are found to be in the sub‐100 fs range, much shorter than those of unprotonated water. Theoretical results support a picture of proton hydration where fluctuating electrical interactions with the solvent and stochastic thermal excitations of low‐frequency modes continuously modify the proton binding site while affecting its motions.
A Bioinspired Synthesis of (±)‐Rubrobramide, (±)‐Flavipucine, and (±)‐Isoflavipucine
Authors: Mizutani Shoma , Komori Kenta , Taniguchi Tohru , Monde Kenji , Kuramochi Kouji , Tsubaki Kazunori 
Published: July 2016

AbstractA biomimetic synthesis of naturally occurring lactams rubrobramide, flavipucine, and isoflavipucine is described. The key step is a regioselective Darzens reaction between isobutyl glyoxal and an α‐bromo‐β‐ketoamide. The construction of the core tricyclic ring system of rubrobramide was achieved by a cascade reaction in a single step from an α,β‐epoxy‐γ‐lactam. Furthermore, the absolute configuration of naturally occurring (+)‐rubrobramide was determined by vibrational circular dichroism. (±)‐Flavipucine and (±)‐isoflavipucine were synthesized from an epoxyimide, which was prepared by reaction of isobutyl glyoxal with a protected α‐bromo‐β‐ketoamide. Deprotection of the epoxyimide and formation of the pyridone ring gave (±)‐flavipucine, which was converted into (±)‐isoflavipucine by thermal isomerization.
Continuous counter‐current chromatography for capture and polishing steps in biopharmaceutical production
Authors: Steinebach Fabian , Müller‐Späth Thomas , Morbidelli Massimo 
Published: July 2016

AbstractThe economic advantages of continuous processing of biopharmaceuticals, which include smaller equipment and faster, efficient processes, have increased interest in this technology over the past decade. Continuous processes can also improve quality assurance and enable greater controllability, consistent with the quality initiatives of the FDA. Here, we discuss different continuous multi‐column chromatography processes. Differences in the capture and polishing steps result in two different types of continuous processes that employ counter‐current column movement. Continuous‐capture processes are associated with increased productivity per cycle and decreased buffer consumption, whereas the typical purity‐yield trade‐off of classical batch chromatography can be surmounted by continuous processes for polishing applications. In the context of continuous manufacturing, different but complementary chromatographic columns or devices are typically combined to improve overall process performance and avoid unnecessary product storage. In the following, these various processes, their performances compared with batch processing and resulting product quality are discussed based on a review of the literature. Based on various examples of applications, primarily monoclonal antibody production processes, conclusions are drawn about the future of these continuous‐manufacturing technologies.
Augmenting Chinese hamster genome assembly by identifying regions of high confidence
Authors: Vishwanathan Nandita , Bandyopadhyay Arpan A. , Fu Hsu‐Yuan , Sharma Mohit , Johnson Kathryn C. , Mudge Joann , Ramaraj Thiruvarangan , Onsongo Getiria , Silverstein Kevin A. T. , Jacob Nitya M. , Le Huong , Karypis George , Hu Wei‐Shou 
Published: July 2016

AbstractChinese hamster Ovary (CHO) cell lines are the dominant industrial workhorses for therapeutic recombinant protein production. The availability of genome sequence of Chinese hamster and CHO cells will spur further genome and RNA sequencing of producing cell lines. However, the mammalian genomes assembled using shot‐gun sequencing data still contain regions of uncertain quality due to assembly errors. Identifying high confidence regions in the assembled genome will facilitate its use for cell engineering and genome engineering. We assembled two independent drafts of Chinese hamster genome by de novo assembly from shotgun sequencing reads and by re‐scaffolding and gap‐filling the draft genome from NCBI for improved scaffold lengths and gap fractions. We then used the two independent assemblies to identify high confidence regions using two different approaches. First, the two independent assemblies were compared at the sequence level to identify their consensus regions as ”high confidence regions“ which accounts for at least 78 % of the assembled genome. Further, a genome wide comparison of the Chinese hamster scaffolds with mouse chromosomes revealed scaffolds with large blocks of collinearity, which were also compiled as high‐quality scaffolds. Genome scale collinearity was complemented with EST based synteny which also revealed conserved gene order compared to mouse. As cell line sequencing becomes more commonly practiced, the approaches reported here are useful for assessing the quality of assembly and potentially facilitate the engineering of cell lines.
A Highly Water‐Tolerant Magnesium(II) Coordination Polymer Derived from a Flexible Layered Structure
Authors: Ochi Rika , Noro Shin‐ichiro , Kamiya Yuichi , Kubo Kazuya , Nakamura Takayoshi 
Published: July 2016

AbstractA two‐dimensional (2D) layered MgII coordination polymer (CP) with a high tolerance for H2O was designed, synthesised, and crystallographically characterised. The synthesis was achieved by the introduction of a flexible 2D layered structure composed of MgII ions and isonicotinate N‐oxide ligands. Owing to its high H2O tolerance, the obtained 2D layered structure has the flexibility to repeatedly adsorb a large amount of H2O associated with interlayer expansion and enable the removal of H2O from a H2O/2‐propanol mixed vapour. These results indicate that the CP could be an excellent dehydrating agent.
Helical Folding Competing with Unfolded Aggregation in Phenylene Ethynylene Foldamers
Authors: Luo Zhouyang , Zhu Ningbo , Zhao Dahui 
Published: July 2016

AbstractThe folding and aggregation behavior of a pair of oligo(phenylene ethynylene) (OPE) foldamers are investigated by means of UV/Vis absorption and circular dichroism spectroscopy. With identical OPE backbones, two foldamers, 1 with alkyl side groups and 2 with triethylene glycol side chains, manifest similar helical conformations in solutions in n‐hexane and methanol, respectively. However, disparate and competing folding and aggregation processes are observed in alternative solvents. In cyclohexane, oligomer 1 initially adopts the helical conformation, but the self‐aggregation of unfolded chains, as a minor component, gradually drives the folding–unfolding transition eventually to the unfolded aggregate state completely. In contrast, in aqueous solution (CH3OH/H2O) both folded and unfolded oligomer 2 appear to undergo self‐association; aggregates of the folded chains are thermodynamically more stable. In solutions with a high H2O content, self‐aggregation among unfolded oligomers is kinetically favored; these oligomers very slowly transform into aggregates of helical structures with greater thermodynamic stability. The folded–unfolded conformational switch thus takes place with the free (nonaggregated) molecules, and the very slow folding transition is due to the low concentration of molecularly dispersed oligomers.
Ferrocenyl Paclitaxel and Docetaxel Derivatives: Impact of an Organometallic Moiety on the Mode of Action of Taxanes
Authors: Wieczorek Anna , Błauż Andrzej , Żal Aleksandra , Arabshahi Homayon John , Reynisson Jóhannes , Hartinger Christian G. , Rychlik Błażej , Plażuk Damian 
Published: July 2016

AbstractA series of ferrocenyl analogues and derivatives of paclitaxel and docetaxel were synthesised and assayed for their antiproliferative/cytotoxic effects, impact on the cell cycle distribution and ability to induce tubulin polymerisation. The replacement of the 3′‐N‐benzoyl group of paclitaxel with a ferrocenoyl moiety, in particular, led to formation of an analogue that was at least one order of magnitude more potent in terms of antiproliferative activity than the parent compound (IC50 values of 0.11 versus 1.11 μm, respectively), but still preserved the classical taxane mode of action, that is, microtubule stabilisation leading to mitotic arrest. Molecular docking studies revealed an unexpected binding pocket in the tubulin structure for the ferrocenoyl group introduced in the paclitaxel backbone.
Chemoselective Synthesis of Carbamates using CO2 as Carbon Source
Authors: Riemer Daniel , Hirapara Pradipbhai , Das Shoubhik 
Published: July 2016

AbstractSynthesis of carbamates directly from amines using CO2 as the carbon source is a straightforward and sustainable approach. Herein, we describe a highly effective and chemoselective methodology for the synthesis of carbamates at room temperature and atmospheric pressure. This methodology can also be applied to protect the amino group in amino acids and peptides, and also to synthesize important pharmaceuticals.
Statistical Analysis of Particle Flux Flowing into the End‐Target in between Attached and Detached States in the Linear Divertor Plasma Simulator NAGDIS‐II
Authors: Tanaka H. , Ohno N. , Onda T. , Takeyama K. , Kajita S. , Kuwabara T. , Tsuji Y. 
Published: July 2016

AbstractWe have investigated the particle flux flowing into the axisymmetric end‐target in the transient state from attached to detached divertor conditions in the linear plasma device NAGDIS‐II. In the transient state, a dramatic decrease of the mean particle flux and a large‐amplitude fluctuation with negative and positive spikes were observed. We have analyzed the fluctuation with a newly suggested analysis technique: pre‐multiplied cubic spectrum with the wavelet transform. Analysis result indicates that these spikes consist of a few kilohertz components. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Simulation Study of Detached Plasmas by Using One‐Dimensional SOL‐Divertor Fluid Code with Virtual Divertor Model
Authors: Togo S. , Takizuka T. , Nakamura M. , Hoshino K. , Ibano K. , Lang T. L. , Ogawa Y. 
Published: July 2016

AbstractThe detached plasmas due to the volume recombination are studied by using one‐dimensional (1D) scrape‐off‐layer‐divertor (SOL‐DIV) plasma fluid code with virtual divertor (VD) model. By introducing the anisotropic ion temperature, the parallel momentum transport equation becomes the first‐order differential and the Mach number at the sheath entrance is determined self‐consistently by the upstream condition. The total particle flux at the divertor plates and the flux amplification factors are shown as functions of the plasma density at the stagnation point and the dependence of these parameters on the heat flux from the core plasma, radial width of the flux tube in the divetor region and the strength of the impurity radiation is investigated. (© 2015 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Steroid pulse therapy was effective for cardiac sarcoidosis with ventricular tachycardia and systolic dysfunction
Authors: Okabe Toshitaka , Yakushiji Tadayuki , Hiroe Michiaki , Oyama Yuji , Igawa Wataru , Ono Morio , Kido Takehiko , Ebara Seitaro , Yamashita Kennosuke , Yamamoto Myong Hwa , Saito Shigeo , Hoshimoto Koichi , Kisaki Amemiya , Isomura Naoei , Araki Hiroshi , Ochiai Masahiko 
Published: July 2016

AbstractA 32‐year‐old man presented with palpitation. He was diagnosed with pulmonary sarcoidosis by lung biopsy. The electrocardiogram showed first‐degree atrioventricular block and complete right bundle branch block (CRBBB). We planned to examine laboratory data, echocardiography, Holter monitoring, and gallium‐67 scintigraphy. Before he went through all these exams, he developed ventricular tachycardia. After defibrillation was performed, his electrocardiogram revealed complete atrioventricular block. We observed elevation of serum angiotensin‐converting enzyme levels. In addition, both of gallium‐67 scintigraphy and 18F‐fluorodeoxyglucose positron emission tomography showed abnormal uptake in the ventricular septum. We diagnosed the patient with cardiac sarcoidosis associated with these arrhythmias. We started treatment with methylprednisolone pulse therapy (1 g daily). After 3 days of steroid pulse therapy, we administered prednisolone 30 mg daily. On day 15, electrocardiogram changed from complete atrioventricular block to first‐degree atrioventricular block and CRBBB. He was discharged with no progression with cardiac sarcoidosis for 2 years.