bluuebunny/crossref_metadata_2025_split huggingface dataset:
Tropical cyclone sensitivity to ocean coupling in the ECMWF coupled model
Authors: Mogensen Kristian S. , Magnusson Linus , Bidlot Jean‐Raymond 
Published: May 2017

AbstractWe present an investigation of the performance of the ECMWF coupled atmosphere‐waves‐ocean model for different ocean and atmosphere resolutions on a series of tropical cyclones in the Western Pacific with the aim to better understand the coupled feedback mechanisms in these extreme conditions. For some of the test cases, we only find little impact of coupling the atmosphere to the ocean, while in others, we observe a very large impact. To further understand these differences, we have selected two tropical cyclones (TCs) as case studies: TC Haiyan (with small impact of coupling) and TC Neoguri (with large impact of coupling). The comparison between these two cases suggests that the upper ocean stratification is the key in determining the strength of the coupled feedback. A strong coupled feedback is found whenever the ocean heat content of the upper layer is low while a very weak coupled feedback is found whenever the ocean has a thick warm mixed layer. The oceanographic response to tropical cyclones for the two storms has been compared to sea surface temperature and derived surface currents from drifting buoys and to subsurface observations from Argo and ship launched XBT's. These comparisons show that we are able to realistically reproduce the atmospheric and oceanographic interaction during tropical cyclone conditions which gives us confidence that the coupled modeling system is physically sound.
Impact of typhoons on the Changjiang plume extension in the Yellow and East China Seas
Authors: Lee Joon Ho , Moon Il‐Ju , Moon Jae‐Hong , Kim Sung‐Hun , Jeong Yeong Yun , Koo Jun‐Ho 
Published: May 2017

AbstractIt is well known that river discharges, winds, ocean currents, and tides are major dynamical factors that determine the distribution and extension of the Changjiang plume (CP) in the Yellow and East China Seas (YECS). Using observations and numerical experiments, this study demonstrates that, in addition to these factors, typhoons in the YECS also play a crucial role in the extension of the CP during the summer season. The hydrographic data observed at the Ieodo Ocean Research Station (IORS) and by a research vessel during the period of Typhoons Ewiniar (0603) and Dianmu (1004) showed that the typhoon‐induced strong vertical mixing modified spatial distribution of the CP significantly, resulting in the delay of the CP's extension by as much as up to 20 days. A series of numerical experiments for Typhoon Dianmu also showed that the typhoon plays a blocking role for the extension of CP for up to 17 days through the vertical mixing process and the change of background winds. In particular, it is found that the delay due to Dianmu in 2010 contributed to the avoidance of potential mass mortality of marine life by preventing the low‐salinity water from spreading to the aquaculture regions near Jeju Island.
The viability of trajectory analysis for diagnosing dynamical and chemical influences on ozone concentrations in the UTLS
Authors: Bergman J. W. , Pfister L. , Kinnison D. E. , Hintsa E. J. , Thornberry T. D. 
Published: May 2017

AbstractTo evaluate the utility of trajectory analysis in the tropical upper troposphere/lower stratosphere, Lagrangian predictions of ozone mixing ratio are compared to observations from the Airborne Tropical TRopopause EXperiment. Model predictions are based on backward trajectories that are initiated along flight tracks. Ozone mixing ratios from analysis data interpolated onto “source locations” (at trajectory termini) provide initial conditions for chemical production models that are integrated forward in time along parcel trajectories. Model sensitivities are derived from ensembles of predictions using two sets of dynamical forcing fields, four sets of source ozone mixing ratios, three trajectory formulations (adiabatic, diabatic, and kinematic), and two chemical production models. Direct comparisons of analysis ozone mixing ratios to observations have large random errors that are reduced by averaging over 75 min (~800 km) long flight tracks. These averaged values have systematic errors that motivate a similarly systematic adjustment to source ozone mixing ratios. Sensitivity experiments reveal a prediction error minimum in parameter space and, thus, a consistent diagnostic picture: The best predictions utilize the source ozone adjustment and a chemical production model derived from Whole Atmosphere Community Climate Model (a chemistry‐climate model) chemistry. There seems to be slight advantages to using ERA‐Interim winds compared to Modern‐Era Retrospective Analysis for Research and Applications and to using kinematic trajectories compared to diabatic; however, both diabatic and kinematic formulations are clearly preferable to adiabatic trajectories. For these predictions, correlations with observations typically decrease as model error is reduced and, thus, fail as a model comparison metric.
Patient specific methods for room‐mounted x‐ray imagers for monoscopic/stereoscopic prostate motion monitoring
Authors: Stevens M. Tynan R. , Parsons Dave D. , Robar James L. 
Published: May 2017

AbstractPurposeTo investigate the improvement of combined monoscopic/stereoscopic prostate motion monitoring with room‐mounted dual x‐ray systems by adopting patient specific methods.MethodsThe linac couch was used as a motion stage to simulate 40 highly dynamic real patient prostate trajectories. For each trajectory, 40 s pretreatment and 120 s treatment periods were extracted to represent a typical treatment fraction. Motion was monitored via continuous stereoscopic x‐ray imaging of a single gold fiducial and images were retrospectively divided into periods of stereoscopic and monoscopic imaging to simulate periodic blocking of the room‐mounted system by the gantry during arc‐based therapy. The accuracy of the combined motion monitoring was assessed by comparison with the linac couch log files. To estimate 3‐D marker position during monoscopic imaging, the use of population statistics was compared to both maximum likelihood estimation and stereoscopic localization based estimation of individualized prostate probability density functions (PDFs) from the pretreatment period. The inclusion of intrafraction updating was compared to pretreatment initialization alone.ResultsCombined mono/stereoscopic localization was successfully implemented. During the transitions from stereoscopic to monoscopic imaging, fiducial localization exhibits sharp discontinuities when population PDFs were employed. Patient specific PDFs successfully reduced the localization error when estimated from stereoscopic localizations, whereas maximum likelihood estimation (MLE) was too unstable in the room‐mounted geometry. Intrafraction stereoscopic updating provided further increases in accuracy. Residual error tended to decrease throughout the treatment fraction, as the patient‐specific PDFs became more refined.ConclusionsThis is the first demonstration of toggled monoscopic/stereoscopic localization using room‐mounted dual x‐ray imagers, enabling continuous intrafraction motion monitoring for these systems. We showed that both pretreatment individualization and intrafraction updating should be used to provide the most accurate motion monitoring.
MRI scanner‐independent specific absorption rate measurements using diffusion coefficients
Authors: Seo Youngseob , Wang Zhiyue J. 
Published: May 2017

AbstractObjectiveThe purpose of this study was to measure specific absorption rate (SAR) during MRI scanning using a human torso phantom through quantification of diffusion coefficients independently of those reported by the scanner software for five 1.5 and 3 T clinical MRI systems from different vendors.MethodsA quadrature body coil transmitted the RF power and a body array coil received the signals. With diffusion tensor imaging, SAR values for three MRI sequences were measured on the five scanners and compared to the nominal values calculated by the scanners.ResultsFor the GE 1.5 T MRI system, the MRI scanner‐reported SAR value was 1.58 W kg‐1 and the measured SAR value was 1.38 W kg‐1. For the Philips 1.5 T MRI scanner, the MRI system‐reported SAR value was 1.48 W kg‐1 and the measured value was 1.39 W kg‐1. For the Siemens 3 T MRI system, the reported SAR value was 2.5 W kg‐1 and the measured SAR value was 1.96 W kg‐1. For two Philips 3 T MRI scanners, the reported SAR values were 1.5 W kg‐1 and the measured values were 1.94 and 1.96 W kg‐1. The percentage differences between the measured and reported SAR values on the GE 1.5 T, Philips 1.5 T, Siemens 3 T, and Philips 3 T were 13.5, 6.3, 24.2, 25.6, and 26.6% respectively.ConclusionThe scanner‐independent SAR measurements using diffusion coefficients described in this study can play a significant role in estimating accurate SAR values as a standardized method.
Subjective Crepitus as a Risk Factor for Incident Symptomatic Knee Osteoarthritis: Data From the Osteoarthritis Initiative
Authors: Lo Grace H. , Strayhorn Michael T. , Driban Jeffrey B. , Price Lori Lyn , Eaton Charles B. , Mcalindon Timothy E. 
Published: May 2017

ObjectiveSubjective crepitus is the reporting of hearing grating, cracking, or popping sounds in and/or around a joint. We aimed to evaluate whether there is an association between crepitus and incident symptomatic knee osteoarthritis (OA) in the Osteoarthritis Initiative (OAI), a multicenter longitudinal US cohort.MethodsKnees without baseline symptomatic OA were included. Crepitus frequency was assessed using a question from the Knee Injury and Osteoarthritis Outcome Score at baseline and at 12, 24, and 36 months. Frequent knee pain and radiographs were assessed at baseline and at annual visits up to 48 months. Radiographic OA was defined as a tibiofemoral Kellgren/Lawrence grade ≥2. Symptomatic OA was defined as a knee with both frequent symptoms and radiographic OA. We performed a repeated‐measures analysis with a predictor of crepitus and outcome of incident symptomatic OA, adjusting for age, sex, and body mass index (BMI), with those never reporting crepitus as the referent group.ResultsThere were a total of 3,495 participants (42.2% male), with mean ± SD age of 61.1 ± 9.2 years and a mean ± SD BMI of 28.2 ± 4.7 kg/m². The odds of incident symptomatic OA were higher with greater frequency of crepitus (never, rarely, sometimes, often, and always, with adjusted odds ratios of (referent), 1.5, 1.8, 2.2, and 3.0, respectively; P < 0.0001 for trend). The group with radiographic OA at OAI baseline but without symptoms contributed 26% of the observations but more than 75% of the incident symptomatic OA cases.ConclusionIn those without symptomatic OA, subjective knee crepitus predicts incident symptomatic OA longitudinally, with most cases occurring in those with preexisting tibiofemoral radiographic OA but without frequent knee pain. However, an important limitation is that patellofemoral OA was not systematically evaluated within the OAI. Subjective crepitus offers utility for the identification of at‐risk individuals, predictive modeling, and future research.
A Methylidene Group in the Phosphonic Acid Analogue of Phenylalanine Reverses the Enantiopreference of Binding to Phenylalanine Ammonia‐Lyases
Authors: Bata Zsófia , Qian Renzhe , Roller Alexander , Horak Jeannie , Bencze László Csaba , Paizs Csaba , Hammerschmidt Friedrich , Vértessy Beáta G. , Poppe László 
Published: May 2017

AbstractAromatic amino acid ammonia‐lyases and aromatic amino acid 2,3‐aminomutases contain the post‐translationally formed prosthetic 3,5‐dihydro‐4‐methylidene‐5H‐imidazol‐5‐one (MIO) group. MIO enzymes catalyze the stereoselective synthesis of α‐ or β‐amino acid enantiomers, making these chemical processes environmentally friendly and affordable. Characterization of novel inhibitors enables structural understanding of enzyme mechanism and recognizes promising herbicide candidates as well. The present study found that both enantiomers of the aminophosphonic acid analogue of the natural substrate phenylalanine and a novel derivative bearing a methylidene at the β‐position inhibited phenylalanine ammonia‐lyases (PAL), representing MIO enzymes. X‐ray methods unambiguously determined the absolute configuration of all tested enantiomers during their synthesis. Enzyme kinetic measurements revealed the enantiomer of the methylidene‐substituted substrate analogue as being a mirror image relation to the natural l‐phenylalanine as the strongest inhibitor. Isothermal titration calorimetry (ITC) confirmed the binding constants and provided a detailed analysis of the thermodynamic driving forces of ligand binding. Molecular docking suggested that binding of the (R)‐ and (S)‐enantiomers is possible by a mirror image packing.magnified image
Durch N‐heterocyclische Carbene katalysierte oxidative Dearomatisierung von Indolen zu spirocyclischen Indoleninen mit quartärem Stereozentrum
Authors: Bera Srikrishna , Daniliuc Constantin G. , Studer Armido 
Published: May 2017

AbstractEine effiziente Methode zur asymmetrischen intramolekularen Dearomatisierung von Indolen unter oxidativer Katalyse mit N‐heterocyclischen Carbenen wird vorgestellt. Nützliche, optisch aktive spirocyclische Indolenine mit quartärem Stereozentrum fallen dabei in exzellenten Ausbeuten und Stereoselektivitäten an. Die Indol‐Ausgangsverbindungen sind leicht zugänglich, und die Reaktionen verlaufen über eine intramolekulare Indolacylierung der 3‐Position mit einem in situ erzeugten Acylazolium‐Intermediat unter Bildung einer spirocyclischen Ketoneinheit.
Unterschiedliche Reaktivität von As4gegenüber Disilenen und Silylenen
Authors: Seitz Andreas E. , Eckhardt Maria , Sen Sakya S. , Erlebach Andreas , Peresypkina Eugenia V. , Roesky Herbert W. , Sierka Marek , Scheer Manfred 
Published: May 2017

AbstractÜber die Aktivierung von gelbem Arsen mit dem Silylen [PhC(NtBu)2SiN(SiMe3)2] (1) und dem Disilen [(Me3Si)2N(η1‐Me5C5)Si=Si(η1‐Me5C5)N(SiMe3)2] (3) wird berichtet. Die Reaktion von As4mit1führt zur präzedenzlosen As10‐Käfigverbindung [(LSiN(SiMe3)2)3As10] (2) (L=PhC(NtBu)2) mit einem As7‐Nortricyclan‐Gerüst, das von Silicium(II)‐bis(trimethylsilyl)amid‐Substituenten enthaltenden Arsasilenresten stabilisiert wird. Dagegen wird die Verbindung [Cp*{(SiMe3)2N}SiAs]2(4), die eine “Butterfly”‐ähnliche Diarsadisilabicyclo[1.1.0]butan‐Einheit enthält, durch die Reaktion von As4mit dem Disilen3gebildet. Beide Verbindungen wurden durch Einkristall‐Röntgenstrukturanalyse, NMR‐Spektroskopie und Massenspektrometrie charakterisiert. Die Ergebnisse zeigen das unterschiedliche Reaktionsverhalten von gelbem Arsen (As4) im Vergleich zum weißen Phosphor (P4) in den Reaktionen mit den entsprechenden Silylenen und Disilenen.
A Short Synthesis of (±)‐3‐Demethoxyerythratidinone by Ligand‐Controlled Selective Heck Cyclization of Equilibrating Enamines
Authors: Blackham Emma E. , Booker‐Milburn Kevin I. 
Published: May 2017

AbstractA short, 5‐step total synthesis of (±)‐3‐demethoxyerythratidinone from a simple pyrrole derivative is described. Features include the formation of gram quantities of a key tricylic aziridine from a challenging photochemical cascade reaction through the use of flow photochemistry. The final step involved a highly unusual Heck cyclization whereby ligand control enabled efficient formation of the natural product in 69 % yield from the minor isomer present in an equilibrating mixture of labile enamines.
Total Syntheses of Aurachins A and B
Authors: Hattori Haruhiko , Yokoshima Satoshi , Fukuyama Tohru 
Published: May 2017

AbstractAurachins A and B are alkaloids having 3‐hydroxyquinoline N‐oxide cores. An efficient method for the synthesis of 3‐hydroxyquinoline N‐oxides was established and is amenable to the total syntheses of aurachins A and B. Alkylation of 1‐(2‐nitrophenyl)butan‐2‐one with farnesyl bromide took place selectively at the benzylic position, and subsequent treatment of the alkylated product with sodium tert‐butoxide in dimethyl sulfoxide gave aurachin B. Alkylation of 1‐(2‐nitrophenyl)butan‐2‐one with an epoxy iodide derived from farnesol was used to access aurachin A.
Confining Excitation Energy in Er3+‐Sensitized Upconversion Nanocrystals through Tm3+‐Mediated Transient Energy Trapping
Authors: Chen Qiushui , Xie Xiaoji , Huang Bolong , Liang Liangliang , Han Sanyang , Yi Zhigao , Wang Yu , Li Ying , Fan Dianyuan , Huang Ling , Liu Xiaogang 
Published: May 2017

AbstractA new class of lanthanide‐doped upconversion nanoparticles are presented that are without Yb3+ or Nd3+ sensitizers in the host lattice. In erbium‐enriched core–shell NaErF4:Tm (0.5 mol %)@NaYF4 nanoparticles, a high degree of energy migration between Er3+ ions occurs to suppress the effect of concentration quenching upon surface coating. Unlike the conventional Yb3+‐Er3+ system, the Er3+ ion can serve as both the sensitizer and activator to enable an effective upconversion process. Importantly, an appropriate doping of Tm3+ has been demonstrated to further enhance upconversion luminescence through energy trapping. This endows the resultant nanoparticles with bright red (about 700‐fold enhancement) and near‐infrared luminescence that is achievable under multiple excitation wavelengths. This is a fundamental new pathway to mitigate the concentration quenching effect, thus offering a convenient method for red‐emitting upconversion nanoprobes for biological applications.
Discovery of Hexagonal Structured Pd–B Nanocrystals
Authors: Kobayashi Keigo , Kobayashi Hirokazu , Maesato Mitsuhiko , Hayashi Mikihiro , Yamamoto Tomokazu , Yoshioka Satoru , Matsumura Syo , Sugiyama Takeharu , Kawaguchi Shogo , Kubota Yoshiki , Nakanishi Hiroshi , Kitagawa Hiroshi 
Published: May 2017

AbstractWe report on hexagonal close‐packed (hcp) palladium (Pd)–boron (B) nanocrystals (NCs) by heavy B doping into face‐centered cubic (fcc) Pd NCs. Scanning transmission electron microscopy–electron energy loss spectroscopy and synchrotron powder X‐ray diffraction measurements demonstrated that the B atoms are homogeneously distributed inside the hcp Pd lattice. The large paramagnetic susceptibility of Pd is significantly suppressed in Pd–B NCs in good agreement with the reduction of density of states at Fermi energy suggested by X‐ray absorption near‐edge structure and theoretical calculations.
Oligonucleotide‐Addressed Covalent 3′‐Terminal Derivatization of Small RNA Strands for Enrichment and Visualization
Authors: Osipenko Aleksandr , Plotnikova Alexandra , Nainytė Milda , Masevičius Viktoras , Klimašauskas Saulius , Vilkaitis Giedrius 
Published: May 2017

AbstractThe HEN1 RNA 2′‐O‐methyltransferase plays important roles in the biogenesis of small non‐coding RNAs in plants and proved a valuable tool for selective transfer of functional groups from cofactor analogues onto miRNA and siRNA duplexes in vitro. Herein, we demonstrate the versatile HEN1‐mediated methylation and alkylation of small RNA strands in heteroduplexes with a range of complementary synthetic DNA oligonucleotides carrying user‐defined moieties such as internal or 3′‐terminal extensions or chemical reporter groups. The observed DNA‐guided covalent functionalization of RNA broadens our understanding of the substrate specificity of HEN1 and paves the way for the development of novel chemo‐enzymatic tools with potential applications in miRNomics, synthetic biology, and nanomedicine.
Oxidative N‐Heterocyclic Carbene Catalyzed Dearomatization of Indoles to Spirocyclic Indolenines with a Quaternary Carbon Stereocenter
Authors: Bera Srikrishna , Daniliuc Constantin G. , Studer Armido 
Published: May 2017

AbstractAn efficient method for the asymmetric intramolecular dearomatization of indoles by using oxidative N‐heterocyclic carbene catalysis is demonstrated. Valuable optically active spirocyclic indolenines bearing an all‐carbon quaternary stereocenter are obtained in excellent yields and with excellent enantioselectivity. The starting indoles are readily prepared and the reactions proceed through an intramolecular indole 3‐acylation with an in situ generated acyl azolium intermediate to form a spirocyclic ketone moiety.
Crystallinity‐Modulated Electrocatalytic Activity of a Nickel(II) Borate Thin Layer on Ni3B for Efficient Water Oxidation
Authors: Jiang Wen‐Jie , Niu Shuai , Tang Tang , Zhang Qing‐Hua , Liu Xiao‐Zhi , Zhang Yun , Chen Yu‐Yun , Li Ji‐Hui , Gu Lin , Wan Li‐Jun , Hu Jin‐Song 
Published: May 2017

AbstractThe exploration of new efficient OER electrocatalysts based on nonprecious metals and the understanding of the relationship between activity and structure of electrocatalysts are important to advance electrochemical water oxidation. Herein, we developed an efficient OER electrocatalyst with nickel boride (Ni3B) nanoparticles as cores and nickel(II) borate (Ni‐Bi) as shells (Ni‐Bi@NB) via a very simple and facile aqueous reaction. This electrocatalyst exhibited a small overpotential of 302 mV at 10 mA cm−2 and Tafel slope of 52 mV dec−1. More interestingly, it was found that the OER activity of Ni‐Bi@NB was closely dependent on the crystallinity of the Ni‐Bi shells. The partially crystalline Ni‐Bi catalyst exhibited much higher activity than the amorphous or crystalline analogues; this higher activity originated from the enhanced intrinsic activity of the catalytic sites. These findings open up opportunities to explore nickel(II) borates as a new class of efficient nonprecious metal OER electrocatalysts, and to improve the electrocatalyst performance by modulating their crystallinity.
Directing Reaction Pathways through Controlled Reactant Binding at Pd–TiO2 Interfaces
Authors: Zhang Jing , Wang Bingwen , Nikolla Eranda , Medlin J. Will 
Published: May 2017

AbstractRecent efforts to design selective catalysts for multi‐step reactions, such as hydrodeoxygenation (HDO), have emphasized the preparation of active sites at the interface between two materials having different properties. However, achieving precise control over interfacial properties, and thus reaction selectivity, has remained a challenge. Here, we encapsulated Pd nanoparticles (NPs) with TiO2 films of regulated porosity to gain a new level of control over catalyst performance, resulting in essentially 100 % HDO selectivity for two biomass‐derived alcohols. This catalyst also showed exceptional reaction specificity in HDO of furfural and m‐cresol. In addition to improving HDO activity by maximizing the interfacial contact between the metal and metal oxide sites, encapsulation by the nanoporous oxide film provided a significant selectivity boost by restricting the accessible conformations of aromatics on the surface.