bluuebunny/crossref_metadata_2025 huggingface dataset:
Capturing the Acoustic Radiation Pattern of Strombolian Eruptions using Infrasound Sensors Aboard a Tethered Aerostat, Yasur Volcano, Vanuatu
Authors: Jolly Arthur D. , Matoza Robin S. , Fee David , Kennedy Ben M. , Iezzi Alexandra M. , Fitzgerald Rebecca H. , Austin Allison C. , Johnson Richard
Published: September 2017

We obtained an unprecedented view of the acoustic radiation from persistent strombolian volcanic explosions at Yasur volcano, Vanuatu, from the deployment of infrasound sensors attached to a tethered aerostat. While traditional ground‐based infrasound arrays may sample only a small portion of the eruption pressure wavefield, we were able to densely sample angular ranges of ~200° in azimuth and ~50° in takeoff angle by placing the aerostat at 38 tethered loiter positions around the active vent. The airborne data joined contemporaneously collected ground‐based infrasound and video recordings over the period 29 July to 1 August 2016. We observe a persistent variation in the acoustic radiation pattern with average eastward directed root‐mean‐square pressures more than 2 times larger than in other directions. The observed radiation pattern may be related to both path effects from the crater walls, and source directionality.
Effects of Parameterized Orographic Drag on Weather Forecasting and Simulated Climatology Over East Asia During Boreal Summer
Authors: Choi Hyun‐Joo , Choi Suk‐Jin , Koo Myung‐Seo , Kim Jung‐Eun , Kwon Young Cheol , Hong Song‐You
Published: September 2017

The impact of subgrid orographic drag on weather forecasting and simulated climatology over East Asia in boreal summer is examined using two parameterization schemes in a global forecast model. The schemes consider gravity wave drag (GWD) with and without lower‐level wave breaking drag (LLWD) and flow‐blocking drag (FBD). Simulation results from sensitivity experiments verify that the scheme with LLWD and FBD improves the intensity of a summertime continental high over the northern part of the Korean Peninsula, which is exaggerated with GWD only. This is because the enhanced lower tropospheric drag due to the effects of lower‐level wave breaking and flow blocking slows down the wind flowing out of the high‐pressure system in the lower troposphere. It is found that the decreased lower‐level divergence induces a compensating weakening of middle‐ to upper‐level convergence aloft. Extended experiments for medium‐range forecasts for July 2013 and seasonal simulations for June to August of 2013–2015 are also conducted. Statistical skill scores for medium‐range forecasting are improved not only in low‐level winds but also in surface pressure when both LLWD and FBD are considered. A simulated climatology of summertime monsoon circulation in East Asia is also realistically reproduced.
A Mechanistic Model of Waterfall Plunge Pool Erosion into Bedrock
Authors: Scheingross Joel S. , Lamb Michael P.
Published: September 2017

Landscapes often respond to changes in climate and tectonics through the formation and upstream propagation of knickzones composed of waterfalls. Little work has been done on the mechanics of waterfall erosion, and instead most landscape‐scale models neglect waterfalls or use rules for river erosion, such as stream power, that may not be applicable to waterfalls. Here we develop a physically based model to predict waterfall plunge pool erosion into rock by abrasion from particle impacts and test the model against flume experiments. Both the model and experiments show that evolving plunge pools have initially high vertical erosion rates due to energetic particle impacts, and erosion slows and eventually ceases as pools deepen and deposition protects the pool floor from further erosion. Lateral erosion can continue after deposition on the pool floor, but it occurs at slow rates that become negligible as pools widen. Our work points to the importance of vertical drilling of successive plunge pools to drive upstream knickzone propagation in homogenous rock, rather than the classic mechanism of headwall undercutting. For a series of vertically drilling waterfalls, we find that upstream knickzone propagation is faster under higher combined water and sediment fluxes and for knickzones composed of many waterfalls that are closely spaced. Our model differs significantly from stream‐power‐based erosion rules in that steeper knickzones can retreat faster or more slowly depending on the number and spacing of waterfalls within a knickzone, which has implications for interpreting climatic and tectonic history through analysis of river longitudinal profiles.
Observation Bias Correction Reveals More Rapidly Draining Lakes on the Greenland Ice Sheet
Authors: Cooley Sarah W. , Christoffersen Poul
Published: September 2017

Rapid drainage of supraglacial lakes on the Greenland Ice Sheet enables the establishment of surface‐to‐bed hydrologic connections and subsequent basal water delivery. Estimates of the number and spatial distribution of rapidly draining lakes vary widely, and no study has so far quantified the impact of observation bias due to cloud cover in satellite imagery on reported frequency of rapid lake drainage. To better understand the rapid drainage mechanism, we map and track an average of 515 supraglacial lakes per year in central West Greenland from 2000 to 2015. We test four previously published definitions of rapid lake drainage and find the proportion of rapidly draining lakes to vary from 3% to 38% and to be strongly dependent on observation frequency. We then apply an observation bias correction and test three new drainage criteria, which reveal a bias‐corrected rapid drainage probability of 36–45%. When observation bias is addressed, we can also show that lakes above 1,600 m are as likely to drain rapidly as lakes located at lower elevations. We conclude that inconsistent detection methodologies and observation bias have obscured the true frequency of rapidly draining lakes and that the rapid lake drainage mechanism will establish surface‐to‐bed hydrologic connections at increasing distance from the margin as supraglacial lakes expand inland under climate warming.
Reducing Disparity in Radio‐Isotopic and Astrochronology‐Based Time Scales of the Late Eocene and Oligocene
Authors: Sahy Diana , Condon Daniel J. , Hilgen Frederik J. , Kuiper Klaudia F.
Published: September 2017

A significant discrepancy of up to 0.6 Myr exists between radio‐isotopically calibrated and astronomically tuned time scales of the late Eocene‐Oligocene. We explore the possible causes of this discrepancy through the acquisition of “high‐precision” 206Pb/238U dating of zircons from 11 volcanic ash beds from the Umbria‐Marche sedimentary succession, which hosts the Global Stratotype Section and Point for the base of the Oligocene. Our results indicate that the four 40Ar/39Ar dates from the Umbria‐Marche succession, which underpin the late Eocene‐Oligocene portion of the Paleogene geomagnetic polarity time scale in the 2012 edition of the Geological Time Scale, are anomalously old by up to 0.5 Myr. Conversely, when integrated with the established magnetic polarity record of the Umbria‐Marche succession, 206Pb/238U (zircon) data from this study result in Oligocene magnetic reversal ages that are generally equivalent to those obtained through the tuning of Ocean Drilling Program (ODP) Site 1218 (equatorial Pacific). Furthermore, our results indicate that the late Eocene tuning of ODP Site 1218, and International Ocean Discovery Program (IODP) Sites U1333–1334 (equatorial Pacific), to the 405 kyr eccentricity signal is accurate, at least back to 36 Ma. Propagating the full uncertainty of our radio‐isotopic data set and, where appropriate, taking into account locally derived astronomical time scales, we arrive at an age of 34.09 ± 0.08 Ma for the Eocene‐Oligocene boundary and 28.11 ± 0.17 Ma for the base of the Chattian.
Pressure‐Temperature‐Deformation‐Time Constraints on the South Tibetan Detachment System in the Garhwal Himalaya (NW India)
Authors: Iaccarino S. , Montomoli C. , Carosi R. , Montemagni C. , Massonne H.‐J. , Langone A. , Jain A. K. , Visonà D.
Published: September 2017

A peculiar feature of the Himalaya is the occurrence of a system of low‐angle normal faults and shear zones, the South Tibetan Detachment System (STDS), at the mountain crests. The STDS was active during synconvergent tectonics. We describe the STDS‐related sheared rocks along the Dhauli Ganga valley, in the Garhwal Himalaya (NW India), where the Malari granite, reported as an undeformed igneous body crosscutting the STDS, occurs. A detailed multidisciplinary study, integrating field‐based, microstructural, petrographic, and geochronological analyses, was carried out on rocks along this valley. We demonstrate how the noncoaxial ductile portion of the STDS affected the upper part of the Greater Himalaya Sequence migmatite, which experienced peak pressure (P)‐temperature (T) conditions of 0.9–1.1 GPa and ≥750°C at ≥24 Ma. This migmatite has been reworked structurally upward leading to the formation of high‐T sillimanite‐bearing mylonites. Further upward, medium‐T shearing deformed the Malari granite and leucogranite dykes, forming medium‐T mylonites. Ductile shearing was temporally constrained, based on new in situ monazite datings and previously published Ar‐Ar geochronology, between ~20 and 15 Ma. We demonstrate that a preserved ductile to brittle spatial and temporal transition of the STDS deformation exists, with the brittle features overprinting ductile ones. Our data shed new light on the geological evolution of the STDS in the NW Himalaya with implications for the relationship and relative timing of partial melting, granite emplacement, and deformation along low‐angle normal faults.
A Framework for Validation of Remotely Sensed Precipitation and Evapotranspiration Based on the Budyko Hypothesis
Authors: Koppa Akash , Gebremichael Mekonnen
Published: September 2017

Despite offering spatially and temporally continuous measurements, the use of remotely sensed P and E in data‐scarce catchments is hindered by the lack of ground‐based measurements that enable comprehensive validation. This study proposes a novel validation framework that characterizes the combined error in the long‐term average estimates of remotely sensed P and E by making use of the Budyko hypothesis, specifically Fu's equation. A Root Mean Square Error (RMSE)‐based error metric that is capable of translating individual biases in P and E estimates onto the Budyko space is developed. A controlled sensitivity experiment using data from Model Parameter Estimation Experiment (MOPEX) catchments in the United States showed that the developed error metric is more sensitive to biases in P compared to biases in estimates of E. Validating the framework using combinations of different satellite‐based estimates of P and E revealed that the framework succeeds in arriving at the same conclusions as a traditional validation method with regards to the quality of P and E data sets. The framework offers a physically consistent, parametrically efficient basis for the selection of remotely sensed P and E data sets for hydrologic studies. Due to lack of consideration for catchment storage in the formulation of Fu's equation, the developed error metric is limited to long temporal time scales. As a result, the error metric is capable of characterizing the bias in P and E data sets and not the variance.
Adaptive variable universe of discourse fuzzy control for a class of nonlinear systems with unknown dead zones
Authors: Wang Rui , Liu Yan‐Jun , Yu Fu‐Sheng , Wang Jia‐Yin , Yang Jin‐Lin
Published: September 2017

In this paper, based on an adaptive nonbackstepping design algorithm, we proposed a novel variable universe of discourse fuzzy control (VUDFC) approach for a class of single‐input–single‐output strict‐feedback nonlinear systems with unknown dead‐zone inputs. Firstly, we convert the form of system into a normal form on the basis of some new state variables and coordinate transformation; at the same time, state‐feedback control is changed to output‐feedback control. Secondly, we design observers to estimate the new unmeasurable states. Then, different from considering the traditional backstepping‐based fuzzy control scheme, we introduce a direct VUDFC scheme, which is mainly based on changing of contraction‐expansion factors to modify the universe of discourse online, and fuzzy rules can automatically reproduce to develop the control performance; thus, the size of initial rule base is greatly reduced. This new algorithm can alleviate tracking error, improve the accuracy of the system, and strengthen robustness. Lastly, according to Lyapunov theorem analysis, we prove that all the signals in the closed‐loop system can be guaranteed to be stable, and the output can track the reference signal very well. Simulation results illustrated the effectiveness of the proposed VUDFC approach.
A Combined Electromagnetic Levitation Melting, Counter‐Gravity Casting, and Mold Preheating Furnace for Producing TiAl Alloy
Authors: Yang Jieren , Wang Hu , Wu Yulun , Wang Xuyang , Hu Rui
Published: September 2017

In this work, the authors describe the development of TiAl castings over a wide range of approaches. To overcome casting defects and cracks that appear in TiAl castings, a novel furnace is designed and constructed. The design combines induction skull melting, counter‐gravity casting, and mold heating, which facilitates both filling and microstructure formation via a controllable process. This aim is to improve shaping capabilities and microstructural control for TiAl castings. Melting and casting experiments on TiAl alloys with a nominal composition corresponding to Ti–48Al–2Cr–2Nb (at%) are carried out and discussed. X‐ray examinations indicate that the shaping of the TiAl components dose not contain macro casting defects, validating the advantages of this technique. The results are of interest to researchers devoted to technical innovations and modifications for TiAl casting at the industrial scale.
Tensile Strength Evolution and Damage Mechanisms of Al–Si Piston Alloy at Different Temperatures
Authors: Wang Meng , Pang Jianchao , Qiu Yu , Liu Haiquan , Li Shouxin , Zhang Zhefeng
Published: September 2017

The Al–Si piston alloys always bear different temperatures because of its peculiar component structure and service condition. Therefore, the tensile strength, elongation to fracture, and corresponding damage mechanisms of Al12SiCuNiMg piston alloys (ASPA) have been investigated with in situ technique at different temperatures. The tensile properties show two‐stage tendencies: the former stage (25–280 °C) is determined by easily broken phases with inherent brittleness (such as primary Si), and the fracture behavior presents rapid brittle fracture after reaching the critical stress (about 430 MPa, based on in situ technique and the elastic stress field model). The later one (280–425 °C) is dominated by particles debonding and θphase coarsening. The plastic deformation behavior, dynamic recovery, and flow process become more significant on account of thermal activation. The Considère criterion h = K indicates that the transition of damage behaviors from insufficient local strength to insufficient matrix strength and the corresponding failure model shifts from brittle to ductile fracture. Based on the damage mechanisms, the elastic field model and thermal activation relation model have been established to characterize the strength of the ASPA at different temperature ranges.
Controlling Coffee Ring Formation during Drying of Inkjet Printed 2D Inks
Authors: He Pei , Derby Brian
Published: September 2017

The morphology of drops of graphene oxide (GO) inks produced by inkjet printing shows a distinctive coffee ring after drying when the mean diameter of the GO is below a critical size. Inks with larger diameter flakes do not show a coffee ring and the transition mean flake diameter decreases as the substrate temperature increases and when the printed drop size decreases. This behavior can be predicted with a model that compares the characteristic time for the agglomeration of high aspect ratio particles in suspension with the time scale for an evaporating liquid drop to begin receding during the drying process. The model is shown to accurately describe the transition from a coffee ring to a uniform dried deposit using a range of GO inks with mean flake size in the range 0.68–35.9 µm, drying temperatures of 20–60 °C, and drop sizes with contact diameter ranging from 30 to 800 µm.
Unravelling Degradation Pathways of Oxide‐Supported Pt Fuel Cell Nanocatalysts under In Situ Operating Conditions
Authors: Schmies Henrike , Bergmann Arno , Drnec Jakub , Wang Guanxiong , Teschner Detre , Kühl Stefanie , Sandbeck Daniel J. S. , Cherevko Serhiy , Gocyla Martin , Shviro Meital , Heggen Marc , Ramani Vijay , Dunin‐Borkowski Rafal E. , Mayrhofer Karl J. J. , Strasser Peter
Published: September 2017

Knowledge of degradation pathways of catalyst/support ensembles aids the development of rational strategies to improve their stability. Here, this is exemplified using indium tin oxide (ITO)‐supported Platinum nanoparticles as electrocatalysts at fuel cell (FC) cathodes under degradation protocols to mimic operating conditions in two potential regimes. The evolution of crystal structure, composition, crystallite and particle size is tracked by in situ X‐ray techniques (small and wide angle scattering), metal dissolution by in situ scanning flow cell coupled with mass spectrometry (SFC ICP‐MS) and Pt surface morphology by advanced electron microscopy. In a regular FC operation regime, Pt poisoning rather than Pt particle growth, agglomeration, dissolution or detachment was found to be the likely origin of the observed degradation and ORR activity losses. In the start‐up regime degradation is actually suppressed and only minor losses in catalytic activity are observed. The presented data thus highlight the excellent nanoparticle stabilization and corrosion resistance of the ITO support, yet point to a degradation pathway involving Pt surface modifications by deposition of sub‐monolayers of support metal ions. The identified degradation pathway of the Pt/oxide catalyst/support couple contributes to our understanding of cathode electrocatalysts for polymer electrolyte fuel cells (PEFC).
Globally optimal linear approach for the design of process equipment: The case of air coolers
Authors: Souza Priscila A. , Costa André L. H. , Bagajewicz Miguel J.
Published: September 2017

In a recent article, Gonçalves et al., introduced a linear and rigorous methodology for equipment design, in particular shell‐and‐tube heat exchanger. Here, we explore its application to air coolers, a problem that we solve globally for the first time. Because the approach is linear, results are globally optimal. The objective function is the total annualized cost. The constraints include the thermal and hydraulic modeling of the process stream flow in the tube bundle and the air flow through the finned surface. In addition, we worked on reducing computing time, through an analysis of different alternatives for the description of the original discrete variables organized in sets of binary variables. The performance of the proposed approach is illustrated through its comparison with an air cooler described in the literature. © 2017 American Institute of Chemical Engineers AIChE J, 64: 886–903, 2018
Ein Instrumentarium von αv‐RGD‐Integrin‐Inhibitoren: Wirkstoffsuche, Herausforderungen und Möglichkeiten
Authors: Hatley Richard J. D. , Macdonald Simon J. F. , Slack Robert J. , Le Joelle , Ludbrook Steven B. , Lukey Pauline T.
Published: September 2017

Es gibt einen Bedarf an wirksamen und sicheren Pharmazeutika für die Behandlung vernachlässigter Krankheiten, und aktuelle Bestrebungen bei der Suche von Inhibitoren des αv‐RGD‐Integrins zielen in diese Richtung. Allerdings erweist sich die Entwicklung von Wirkstoffen im Bereich der αv‐Integrine aufgrund der sehr ähnlichen Strukturen dieser Rezeptoren und der polaren, zwitterionischen Natur des Pharmakophors als notorisch schwierig. Ziel dieses Aufsatzes ist es, einen Leitfaden für die Wirkstoffsuche in diesem Gebiet anzubieten. Wir tun dies, indem wir hier ein Instrumentarium von αv‐Inhibitoren bestehend aus niedermolekularen Verbindungen (“kleinen Molekülen”) und Antikörpern vorstellen. Niedermolekulare αv‐Verbindungen mit erweiterten Profilen in αvβ1‐, αvβ3‐, αvβ5‐, αvβ6‐ und αvβ8‐Zelladhäsionsassays wurden zusammengetragen, um die Auswahl der richtigen Verbindung für das richtige Experiment zu unterstützen. Dies sollte außerdem helfen, die partiellen Selektivitätsprofile von Verbindungen besser zu verstehen, die in unterschiedlichen Assays unterschiedlicher Forschungsinstitute generiert wurden. Die Perspektiven der zukünftigen Forschung an αv‐Integrinen und die zentral wichtige Targetvalidierung werden diskutiert; fundierte Kenntnisse der Selektivität individueller RGD‐αv‐Integrine sind hier ganz entscheidend. Einblicke in das Design niedermolekularer RGD‐Chemotypen für die topische oder orale Verabreichung werden vorgestellt und klinische Befunde zu fortgeschrittenen Molekülen betrachtet.
Phosphine (oxide)‐(thio) phenolate palladium complexes: Synthesis, characterization and (co)polymerization of norbornene
Authors: Zhang Yanping , Mu Hongliang , Li Yanguo , Li Yuesheng
Published: September 2017

A series of palladium complexes (2a–2g) (2a: [6‐tBu‐2‐PPh2‐C6H3O]PdMe(Py); 2b: [6‐C6F5–2‐PPh2‐C6H3O]PdMe(Py); 2c: [6‐tBu‐2‐PPhtBu‐C6H3O]PdMe(Py); 2d: [2‐PPhtBu‐C6H4O] PdMe(Py); 2e: [6‐SiMe3–2‐PPh2‐C6H3O]PdMe(Py); 2f: [2‐tBu‐6‐(Ph2P=O)‐C6H3O]PdMe(Py); 2g: [6‐SiMe3–2‐(Ph2P=O)‐C6H3S]PdMe(Py)) bearing phosphine (oxide)‐(thio) phenolate ligand have been efficiently synthesized and characterized. The solid‐state structures of complexes 2d, 2f and 2g have been further confirmed by single‐crystal X‐ray diffraction, which revealed a square‐planar geometry of palladium center. In the presence of B(C6F5)3, these complexes can be used as catalysts to polymerize norbornene (NB) with relatively high yields, producing vinyl‐addition polymers. Interestingly, 2a/B(C6F5)3 system catalyzed the polymerization of NB in living polymerization manner at high temperature (polydispersity index 1.07, Mn up to 1.5 × 104). The co‐polymerization of NB and polar monomers was also studied using catalysts 2a and 2f. All the obtained co‐polymers could dissolve in common solvent.
Click functionalization of magnetite nanoparticles: A new magnetically recoverable catalyst for the selective epoxidation of olefins
Authors: Masteri‐Farahani Majid , Shahsavarifar Samaneh
Published: September 2017

A new magnetically recoverable heterogeneous molybdenum catalyst was developed by means of a click chemistry approach. First, silica‐coated magnetite nanoparticles were functionalized using a bidentate ligand via thiol–ene click reaction of mercaptopropyl‐modified magnetite nanoparticles with acrylic acid. Then, a molybdenum complex was covalently supported on the surface of the clicked silica‐coated magnetite nanoparticles. The prepared catalyst was characterized using Fourier transform infrared and inductively coupled plasma optical emission spectroscopies, X‐ray diffraction, vibrating sample magnetometry and transmission electron microscopy. The catalytic performance of the prepared heterogeneous catalyst was investigated in the epoxidation of olefins with tert‐butyl hydroperoxide as oxidant. This catalyst could be reused for five runs without significant loss of activity and selectivity.
Design and Synthesis of a Highly Selective JAK3 Inhibitor for the Treatment of Rheumatoid Arthritis
Authors: He Linhong , Pei Heying , Lan Tingxuan , Tang Minghai , Zhang Chufeng , Chen Lijuan
Published: September 2017

Selective inhibition of Janus kinase 3 (JAK3) has been identified as an important strategy for the treatment of autoimmune disorders. Based on the unique cysteine 909 residue (Cys909) of JAK3 at the gatekeeper position, we have developed a new irreversible covalent inhibitor, III‐4, which is highly potent and selective in targeting JAK3. Importantly, III‐4 selectively inhibited JAK3 (IC50 = 57 ± 1.21 nM) over other JAKs (IC50 > 10 µM) and Cys909 kinome members (IC50 > 1 µM). A cellular selectivity study also confirmed that III‐4 preferentially inhibited JAK3 over JAK1 in JAK/STAT signaling. Moreover, the fact that III‐4 covalently modified the Cys909 residue in JAK3 was clearly validated by mass spectrometry and covalent docking analysis. Based on the favorable target profiles, the pharmacokinetic properties and its low toxicity, III‐4 exhibited better efficacy than tofacitinib in impeding disease progression in CIA mice, without any significant adverse effects. Taken together, III‐4 is a potent, selective, and durable inhibitor of JAK3 and has the potential for the treatment of inflammatory disorders and autoimmune diseases, such as rheumatoid arthritis.
An application of integration approaches for archaeo‐geophysical data: Case study from Aizanoi
Authors: Küçükdemirci Melda , Özer Elif , Piro Salvatore , Baydemir Niyazi , Zamuner Daniela
Published: September 2017

Transforming multi‐dimensional datasets, containing measurements of different physical parameters recorded at the same location, into a single composite imagery is quite important and frequently used in geophysical analysis as well as other scientific disciplines. This study focuses on the application of several different integration approaches for archaeo‐geophysical data with a purpose of achieving complementary and improved information about the buried archaeological target by generating a single data set from multiple geophysical methods. An extensive geophysical survey using ground penetrating radar (GPR) and differential magnetic methods was made in different parts of the Aizanoi archaeological site (Cavdarhisar, Kutahya, Turkey) to locate and enhance subsurface archaeological structures. However, in this article, the outputs of graphical, mathematical and statistical integration approaches, which are applied both on synthetic images and real field case data, are presented and discussed. Comparing these results and experimental applications, mathematical and statistical integration approaches provide more useful and practicable information than just the single distinct datasets from each geophysical parameter studied.
Harzianone Biosynthesis by the Biocontrol Fungus Trichoderma
Authors: Barra Lena , Dickschat Jeroen S.
Published: September 2017

Analysis of the volatile terpenes produced by seven fungal strains of the genus Trichoderma by use of a closed‐loop stripping apparatus (CLSA) revealed a common production of harzianone, a bioactive, structurally unique diterpenoid consisting of a fused tetracyclic 4,7,5,6‐membered ring system. The terpene cyclization mechanism was studied by feeding experiments using selectively 13C‐ and 2H‐labeled synthetic mevalonolactone isotopologues, followed by analysis of the incorporation patterns by 13C NMR spectroscopy and GC/MS. The structure of harzianone was further supported from a 13C,13C COSY experiment of the in‐vivo‐generated fully 13C‐labeled diterpene.
Gastrointestinal stromal tumor: an incidental finding during laparoscopic bariatric surgery
Authors: Saurabh Shireesh
Published: September 2017

Key Clinical Message

Gastrointestinal stromal tumor (GIST) is the most common mesenchymal tumor of the gastrointestinal tract. Lack of clinical symptoms and findings on preoperative upper endoscopy makes its diagnosis difficult in bariatric patients. A laparoscopic resection of the gastric GIST during bariatric surgery is associated with good long‐term prognosis.
Ag‐Nanoparticle‐Anchored rGO‐Coated MIL‐88B(Fe) Hybrids as Robust Electrocatalysts for the Highly Efficient Oxygen Evolution Reaction at Neutral pH
Authors: Islam Dewan Azharul , Barman Koushik , Jasimuddin Sk , Acharya Himadri
Published: September 2017

The design of highly efficient, robust, and stable electrocatalysts for the oxygen evolution reaction (OER) remains a crucial challenge for the advancement of a number of renewable energy applications, including conversion and storage technology. Here, a robust water oxidation catalyst, Ag‐nanoparticle‐anchored reduced graphene oxide (rGO)‐coated MIL‐88B(Fe) hybrids (AgNPs@rGO/MIL‐88B(Fe)), is developedfor a highelectrocatalytic performance in the OER. Initially, MIL‐88B(Fe) is synthesized through an in situ process in exfoliated graphene oxide dispersion, forming a GO‐coated MIL‐88B(Fe) hybrid. Ag nanoparticles (ca. 3 nm) are then deposited through simultaneous reduction of silver ions and GO to form a robust AgNPs@rGO/MIL‐88B(Fe) combined catalyst. The new catalyst material was tested for the OER and exhibited remarkable catalytic performance, affording a current density of 1 mA cm−2 at a very low overpotential of approximately 395 mV in buffered solution (pH∼7). Furthermore, the sustained catalyst stability with Tafel slopes of 60 mV dec−1 is one of the best electrocatalytic performances reported at neutral pH.
Copper‐Mediated Introduction of the CF2PO(OEt)2 Motif: Scope and Limitations
Authors: Ivanova Maria V. , Bayle Alexandre , Besset Tatiana , Pannecoucke Xavier , Poisson Thomas
Published: September 2017

Herein, a general procedure to access CF2PO(OEt)2‐containing molecules is reported. The reagent CuCF2PO(OEt)2 is accessible by a simple protocol and a broad range of substrates can be functionalised. The procedure allows the conversion of aryl diazonium salts, as well as aryl, heteroaryl, vinyl and alkynyl iodonium salts, into the corresponding fluorinated molecules at room temperature. Mechanistic studies were performed to gain a better understanding of the reaction pathway. Under similar conditions, vinyl and aryl iodides, allyl halides, and benzyl bromides were also functionalised, and the scope and limitations of the reaction were studied. Finally, the procedure was extended to disulfides to offer new access to SCF2PO(OEt)2‐containing molecules.
Biosynthesis and Total Synthesis of Pyrronazol B: a Secondary Metabolite from Nannocystis pusilla
Authors: Witte Swjatoslaw N. R. , Hug Joachim J. , Géraldy Magalie N. E. , Müller Rolf , Kalesse Markus
Published: September 2017

The first stereoselective total synthesis of the natural product pyrronazol B, which contains a chlorinated pyrrole–oxazole–pyrone framework, has been achieved. Genome sequencing of the myxobacterial producer strain Nannocystis pusilla Ari7 led to the identification of the putative biosynthetic gene cluster. The proposed biosynthetic pathway was supported by feeding experiments with stable isotopes of three biosynthetic building blocks, namely l‐proline, l‐serine, and l‐methionine.
Novel Fluorophores based on Regioselective Intramolecular Friedel–Crafts Acylation of the Pyrene Ring Using Triflic Acid
Authors: Jousselin‐Oba Tanguy , Sbargoud Kamal , Vaccaro Gianfranco , Meinardi Francesco , Yassar Abderrahim , Frigoli Michel
Published: September 2017

The extension of the pyrene ring from dimethyl 2,2′‐(pyrene‐1,6‐diyl)dibenzoate derivatives by an intramolecular Friedel–Crafts acylation can be realized in an efficient and regioselective manner using triflic acid as proton source. Naphtho‐tetracenone derivatives are obtained in high yields at room temperature while Bis‐tetracene‐diones are prepared upon heating. Both products display interesting fluorescence properties in the visible range with quantum yields varying from 50 to 60 %.
Sulfonylative and Azidosulfonylative Cyclizations by Visible‐Light‐Photosensitization of Sulfonyl Azides in THF
Authors: Zhu Shaoqun , Pathigoolla Atchutarao , Lowe Grace , Walsh Darren A. , Cooper Mick , Lewis William , Lam Hon Wai
Published: September 2017

The generation of sulfonyl radicals from sulfonyl azides using visible light and a photoactive iridium complex in THF is described. This process was used to promote sulfonylative and azidosulfonylative cyclizations of enynes to give several classes of highly functionalized heterocycles. The use of THF as the solvent is critical for successful reactions. The proposed mechanism of radical initiation involves the photosensitized formation of a triplet sulfonyl nitrene, which abstracts a hydrogen atom from THF to give a tetrahydrofuran‐2‐yl radical, which then reacts with the sulfonyl azide to generate the sulfonyl radical.
The effect of Landau damping on the power absorption in a helicon plasma source driven by an m = 0 antenna
Authors: Soltani B. , Habibi M. , Zakeri‐khatir H.
Published: September 2017

Landau damping is one of the most important mechanisms for the description of wave dissipation and efficient power absorption in helicon plasma sources. Numerical analysis using the MATLAB code is carried out to determine the dispersion relation of the helicon plasma and calculate the axial wavenumber for m = 0 mode in both Trivelpiece‐Gould (TG) and helicon plasma density regimes. In addition, the MATLAB code is coupled to the CST Microwave Studio (Ms) code to examine the collisionless power absorption due to Landau damping in a helicon source driven by a single‐loop antenna. The effects of some parameters, such as the electron temperature (Te), the external magnetic field strength (B0), and the antenna excitation frequency (f), on the Landau damping are investigated for electron density ranging from 1 × 1016 to 1 × 1020 m–3. Our findings indicate that, for a given set of plasma parameters, Landau damping shows different behaviors on the power deposition. For instance, increasing the excitation frequency has considerable effect on the collisionless absorbed power in the range of values from 3 × 1017 to 3 × 1019 m–3 of the electron density. Also, for f  = 13.56 MHz, Te = 3 eV, and B0 = 100 G, there is a specific electron density (i.e., ne = 2 × 1018 m–3) beyond which increasing the electron temperature causes a decrease in the collisionless power absorption; the opposite is true for lower plasma density (i.e., ne < 2 × 1018 m–3). Furthermore, the obtained results show that Landau damping has considerable effect on the power absorption in the helicon source at low pressure regime (e.g., P = 1 mTorr) with low external magnetic field strength (e.g., B0 < 200 G).
Quantitating ADCC against adherent cells: Impedance‐based detection is superior to release, membrane permeability, or caspase activation assays in resolving antibody dose response
Authors: Tóth Gábor , Szöllősi János , Vereb György
Published: September 2017

Monoclonal antibody‐based immunotherapeutics will dominate Pharma's next generation of blockbuster drugs, and Fc‐associated functions, including antibody dependent cellular cytotoxicity (ADCC) are among the highly desired activities mediated by these antibodies. Therefore, quantitative evaluation of ADCC is required during drug development. Our objective was to find the most suitable and reliable nonradioactive method for quantitative analysis of in vitro ADCC against adherent cells, which often serve as models for solid tumors. The test system was comprised the HER2 positive JIMT‐1 cells targeted by the specific therapeutic antibodies trastuzumab (Herceptin®) and pertuzumab (Perjeta®). These cells are resistant to the direct biological effects of these antibodies, and, therefore, allow the isolated assessment of ADCC. We compared fluorescein diacetate (FDA) and carboxyfluorescein diacetate succinimidyl ester (CFSE) release as a fluorescent alternative to 51Cr release; propidium iodide (PI) uptake revealing increased membrane permeability; the PanToxiLux assay measuring ADCC induced pro‐apoptotic protease activity in flow cytometry; and an impedance‐based real time cell adhesion test. We found that release assays are compromised by high spontaneous release of the label. PI uptake could not differentiate well between spontaneous NK activity and specific ADCC. The PanToxiLux assay, besides allowing for shorter assay times, offers improvement over the previous approaches in distinguishing spontaneous and antibody mediated NK action, but, probably owed to the prolonged detached state of adherent target cells, only at highly saturating antibody concentrations. In the case of adherent target cells, impedance‐based cell analysis attains functional information exclusively on the target cells without having to label them for distinguishing from effectors or assay readout. It also allows continuous monitoring for days, and specifically detects target cell detachment, as the final functional consequence of ADCC. The sensitivity of this method even allows for quantitating the additivity and saturability of ADCC as a function of antibody concentration. We conclude that impedance‐based assays are the most sensitive for quantitatively assessing in vitro ADCC on adherent target cells. © 2017 International Society for Advancement of Cytometry
Scenarios reveal pathways to sustain future ecosystem services in an agricultural landscape
Authors: Qiu Jiangxiao , Carpenter Stephen R. , Booth Eric G. , Motew Melissa , Zipper Samuel C. , Kucharik Christopher J. , Chen Xi , Loheide Steven P. , Seifert Jenny , Turner Monica G.
Published: September 2017

Sustaining food production, water quality, soil retention, flood, and climate regulation in agricultural landscapes is a pressing global challenge given accelerating environmental changes. Scenarios are stories about plausible futures, and scenarios can be integrated with biophysical simulation models to explore quantitatively how the future might unfold. However, few studies have incorporated a wide range of drivers (e.g., climate, land‐use, management, population, human diet) in spatially explicit, process‐based models to investigate spatial‐temporal dynamics and relationships of a portfolio of ecosystem services. Here, we simulated nine ecosystem services (three provisioning and six regulating services) at 220 × 220 m from 2010 to 2070 under four contrasting scenarios in the 1,345‐km2 Yahara Watershed (Wisconsin, USA) using Agro‐IBIS, a dynamic model of terrestrial ecosystem processes, biogeochemistry, water, and energy balance. We asked (1) How does ecosystem service supply vary among alternative future scenarios? (2) Where on the landscape is the provision of ecosystem services most susceptible to future social‐ecological changes? (3) Among alternative future scenarios, are relationships (i.e., trade‐offs, synergies) among food production, water, and biogeochemical services consistent over time? Our results showed that food production varied substantially with future land‐use choices and management, and its trade‐offs with water quality and soil retention persisted under most scenarios. However, pathways to mitigate or even reverse such trade‐offs through technological advances and sustainable agricultural practices were apparent. Consistent relationships among regulating services were identified across scenarios (e.g., trade‐offs of freshwater supply vs. flood and climate regulation, and synergies among water quality, soil retention, and climate regulation), suggesting opportunities and challenges to sustaining these services. In particular, proactive land‐use changes and management may buffer water quality against undesirable future climate changes, but changing climate may overwhelm management efforts to sustain freshwater supply and flood regulation. Spatially, changes in ecosystem services were heterogeneous across the landscape, underscoring the power of local actions and fine‐scale management. Our research highlights the value of embracing spatial and temporal perspectives in managing ecosystem services and their complex interactions, and provides a system‐level understanding for achieving sustainability of the food–water–climate nexus in agricultural landscapes.
The contrasting effect of biocrusts on shallow‐rooted perennial plants (hemicryptophytes): Increasing mortality (through evaporation) or survival (through runoff)
Authors: Kidron Giora J. , Aloni Irith
Published: September 2017

The effect of biocrusts on plants is ambiguous. At the Nizzana research site (Negev Desert, Israel), frequent droughts in the last 2 decades resulted in high shrub mortality, which has been explained by the negative effect of the low‐albedo crusts on soil water evaporation. Nevertheless, shallow‐rooted perennial plants, such as Stipagrostis plumosa and Cyperus sp., exhibit relatively little mortality. We hypothesized that these hemicryptophytes (HCs) grow at or adjacent to small 2‐ to 4‐m2 depressions (termed IDDEP) in the interdune (ID), which are scattered within the undulating terrain (termed IDINC) of ID, and as previously found, serve as sink for short‐distance runoff from IDINC to IDDEP. To test this, we randomly demarcated 50 5 × 5 m plots in the ID and semistable uncrusted dune crest (CR), and the cover of live HCs in the three habitats CR, IDINC, and IDDEP were monitored. In addition, the available water content (AWC) for the 0‐ to 80‐cm depth was measured during 2012–2014. Although AWC exhibited a clear pattern with IDDEP > CR > IDINC, HCs were almost absent from IDINC (above ground biomass of 0.3 kg/ha) but relatively high in IDDEP (55.3 kg/ha) and CR (113.0 kg/ha). The high biomass at CR and IDDEP is explained by higher AWC due to lower evaporation or runoff addition, respectively. The findings highlight the contrasting role played by the biocrust: Although responsible for the mortality of most perennials at IDINC due to increased evaporation, biocrusts assist the survival of relatively shallow‐rooted perennials at IDDEP through runoff generation.
Shrub patch configuration in relation to precipitation and soil properties in Northwest China
Authors: Fan Ying , Li Xiao‐Yan , Huang Yong‐Mei , Li Liu , Zhang Jing‐Hui , Liu Qi , Jiang Zhi‐Yun
Published: September 2017

Shrub patch configuration is a long‐term evolutionary response to several environmental drivers and an equilibrium state in species competition. However, the variance in configuration along the precipitation gradient and its association with climate, soil, and adjacent vegetation remains unclear. Our study aimed to assess the variation of shrub patch configuration along a climatic gradient and the factors that affect shrub patch configuration, on the Inner Mongolia Plateau of Northwest China. Results showed that climate, soil, and vegetation contributed to 72.9% of the variance in shrub patch configuration. Interestingly, interspace/shrub radius ratio showed a decreasing trend with increasing precipitation transect. Patch size was positively correlated with aboveground biomass of interspace grass. Shrubs generally aggregated in high patches with low density on coarse soil texture, and vice versa. Moreover, shrub patches tended to occupy a larger percentage of landscape with increasing rainfall. To our knowledge, our study provides the first quantification of the effects of climate, soil, and vegetation on shrub patch configuration along a precipitation gradient in Northwest China and may contribute to a better understanding of the structure and functions of shrub ecosystems with a broader ecological application in arid and semiarid regions.
Anhydrous Dinitrogen Trioxide Solutions for Brønsted Acid Free Nitrous Acid Chemistry
Authors: Rosadiuk Kristopher A. , Bohle D. Scott
Published: September 2017

Dinitrogen trioxide, N2O3, is readily prepared and stabilized in high concentrations in dry organic solvents at normal working temperatures. These conditions allow for facile acid and water free nitrosation and nitration reactions for which three examples are given here: the preparation of benzenediazonium nitrite, [PhN2][NO2]; nitrosyl chloride, NOCl, and nitrosylsulfuric acid, (ONOSO3H).
Changes in Physicochemical and Microbiological Parameters of Short and Long‐Lived Veiled (Cloudy) Virgin Olive Oil Upon Storage in the Dark
Authors: Zullo Biagi A. , Ciafardini Gino
Published: September 2017

Veiled (cloudy) virgin olive oil is an intermediate state before sedimentation of unfiltered newly produced olive oil. Despite growing consumer interest in unfiltered veiled virgin olive oil, one of the key factors limiting wider distribution is its low physical stability. The present research describes the production of long‐lived veiled virgin olive oil generated in a new storage system to prevent the rapid sedimentation of unfiltered olive oils. Chemical and microbiological analyses were conducted with three short‐lived (3–5 months) and three long‐lived (1 year) veiled virgin olive oils that contained different concentrations of polar phenolic compounds. The best results were demonstrated in both veiled olive oils types when the polar phenolic compounds content was greater than 130 mg caffeic acid equivalent per kg. The solid particles (98%) present in the short‐lived virgin veiled oil settled onto the bottom of the canisters, producing sediments, during storage for 6 months; while only 2–6% settled in the long‐lived veiled oil. The microbial activity was higher in both types of veiled virgin oil of low polar phenols content decreasing the quality of the product in the short‐lived veiled oil.

Practical Applications: Unfiltered veiled virgin olive oils are gaining popularity among some chefs and consumers, who judge the opalescent appearance as an indicator of higher wholesomeness. Presently, large‐scale production is prevented because it does not meet the expectations of consumers seeking a stable product, since, due to the sedimentation process, the opalescence usually disappears after the first weeks or months of storage. In this research, we evaluated a new storage system capable of preventing the rapid sedimentation of veiled virgin olive oils, extending the opalescence life from 3 to 6 months to approximately 1 year. The physicochemical and microbiological parameters, were assessed for three short‐lived and long‐lived veiled virgin olive oils. The best results were found for oils containing higher concentration of total polar phenolic compounds.

The opalescent aspect of veiled olive oil disappears with sedimentation during the first 6 months. A new storage system capable of prevent the rapid sedimentation of unfiltered olive oil, generates the production of long‐lived veiled olive oil in which the opalescence life is extended from 3 to 6 months to approximately 1 year. Physicochemical and microbiological studies demonstrate that the oil quality is compromised primarily in the short‐lived veiled olive oil with the lowest total polyphenols content.
Comparison of a polymeric pseudostationary phase in EKC with ODS stationary phase in RP‐HPLC
Authors: Ni Xinjiong , Zhang Min , Xing Xiaoping , Cao Yuhua , Cao Guangqun
Published: September 2017

Poly(stearyl methacrylate‐co‐methacrylic acid) (P(SMA‐co‐MAA)) was induced as pseudostationary phase (PSP) in electrokinetic chromatography (EKC). The n‐octadecyl groups in SMA were the same as that in octadecylsilane (ODS) C18 column. Thus, the present work focused on the comparison of selectivity between polymeric PSP and ODS stationary phase (SP), and the effect of organic modifiers on the selectivity of polymeric PSP and ODS SP. 1‐butanol could directly interacted with PSP as a Class I modifier, and improved both of the methylene selectivity and polar group selectivity. When the analysis times were similar, the polymeric PSP exhibited better methylene selectivity and polar group selectivity. Although the hydrophobic groups were similar, the substituted benzenes elution order was different between polymeric PSP and ODS SP. Linear solvation energy relationships (LSER) model analysis found that polymeric PSP and ODS SP exhibited two same key factors in selectivity: hydrophobic interaction and hydrogen bonding acidity. But polymeric PSP exhibited relatively strong n‐ and π‐electrons interaction to the analytes.