bluuebunny/crossref_metadata_2025_split huggingface dataset:
Enantioselective Preparation of (
S
)‐5‐Oxo‐5,6‐dihydro‐
2H
‐pyran‐2‐yl Benzoate
Authors: Benkovics* Tamas , Ortiz Adrian , Guo Zhiwei , Goswami Animesh , Deshpande Prashant 
Published: June 2015

Abstract
Derivatives of lactol contain a rich array of functionalities for elaboration in a diastereoselective fashion, and have been shown to be convenient starting materials for natural product synthesis. The methods described in this article illustrate a chromatography‐free synthesis of crystalline benzoate in high enantioselectivity using commercially available chemicals.
Biological and physical controls on N2, O2, and CO2 distributions in contrasting Southern Ocean surface waters
Authors: Tortell Philippe D. , Bittig Henry C. , Körtzinger Arne , Jones Elizabeth M. , Hoppema Mario 
Published: June 2015

AbstractWe present measurements of pCO2, O2 concentration, biological oxygen saturation (ΔO2/Ar), and N2 saturation (ΔN2) in Southern Ocean surface waters during austral summer, 2010–2011. Phytoplankton biomass varied strongly across distinct hydrographic zones, with high chlorophyll a (Chl a) concentrations in regions of frontal mixing and sea ice melt. pCO2 and ΔO2/Ar exhibited large spatial gradients (range 90 to 450 µatm and −10 to 60%, respectively) and covaried strongly with Chl a. However, the ratio of biological O2 accumulation to dissolved inorganic carbon (DIC) drawdown was significantly lower than expected from photosynthetic stoichiometry, reflecting the differential time scales of O2 and CO2 air‐sea equilibration. We measured significant oceanic CO2 uptake, with a mean air‐sea flux (~ −10 mmol m−2 d−1) that significantly exceeded regional climatological values. N2 was mostly supersaturated in surface waters (mean ΔN2 of +2.5%), while physical processes resulted in both supersaturation and undersaturation of mixed layer O2 (mean ΔO2phys = 2.1%). Box model calculations were able to reproduce much of the spatial variability of ΔN2 and ΔO2phys along the cruise track, demonstrating significant effects of air‐sea exchange processes (e.g., atmospheric pressure changes and bubble injection) and mixed layer entrainment on surface gas disequilibria. Net community production (NCP) derived from entrainment‐corrected surface ΔO2/Ar data, ranged from ~ −40 to > 300 mmol O2 m−2 d−1 and showed good coherence with independent NCP estimates based on seasonal mixed layer DIC deficits. Elevated NCP was observed in hydrographic frontal zones and stratified regions of sea ice melt, reflecting physical controls on surface water light fields and nutrient availability.
MAVEN IUVS observations of the aftermath of the Comet Siding Spring meteor shower on Mars
Authors: Schneider N. M. , Deighan J. I. , Stewart A. I. F. , McClintock W. E. , Jain S. K. , Chaffin M. S. , Stiepen A. , Crismani M. , Plane J. M. C. , Carrillo‐Sánchez J. D. , Evans J. S. , Stevens M. H. , Yelle R. V. , Clarke J. T. , Holsclaw G. M. , Montmessin F. , Jakosky B. M. 
Published: June 2015

AbstractWe report the detection of intense emission from magnesium and iron in Mars' atmosphere caused by a meteor shower following Comet Siding Spring's close encounter with Mars. The observations were made with the Imaging Ultraviolet Spectrograph, a remote sensing instrument on the Mars Atmosphere and Volatile EvolutioN spacecraft orbiting Mars. Ionized magnesium caused the brightest emission from the planet's atmosphere for many hours, resulting from resonant scattering of solar ultraviolet light. Modeling suggests a substantial fluence of low‐density dust particles 1–100 µm in size, with the large amount and small size contrary to predictions. The event created a temporary planet‐wide ionospheric layer below Mars' main dayside ionosphere. The dramatic meteor shower response at Mars is starkly different from the case at Earth, where a steady state metal layer is always observable but perturbations caused by even the strongest meteor showers are challenging to detect.
The evolution of habitable climates under the brightening Sun
Authors: Wolf E. T. , Toon O. B. 
Published: June 2015

AbstractOn water‐dominated planets, warming from increased solar insolation is strongly amplified by the water vapor greenhouse feedback. As the Sun brightens due to stellar evolution, Earth will become uninhabitable due to rising temperatures. Here we use a modified version of the Community Earth System Model from the National Center for Atmospheric Research to study Earth under intense solar radiation. For small (≤10%) increases in the solar constant (S0), Earth warms nearly linearly with climate sensitivities of ~1 K/(W m−2) and global mean surface temperatures below 310 K. However, an abrupt shift in climate is found as the solar constant is increased to +12.5% S0. Here climate sensitivity peaks at ~6.5 K/(W m−2), while global mean surface temperatures rise above 330 K. This climatic transition is associated with a fundamental change to the radiative‐convective state of the atmosphere. Hot, moist climates feature both strong solar absorption and inefficient radiative cooling in the low atmosphere, thus yielding net radiative heating of the near‐surface layers. This heating forms an inversion that effectively shuts off convection in the boundary layer. Beyond the transition, Earth continues to warm but with climate sensitivities again near unity. Conditions conducive to significant water loss to space are not found until +19% S0. Earth remains stable against a thermal runaway up to at least +21% S0, but at that point, global mean surface temperatures exceed 360 K, and water loss to space becomes rapid. Water loss of the oceans from a moist greenhouse may preclude a thermal runaway.
On the dynamics and kinematics of two‐fluid‐phase flow in porous media
Authors: Gray W. G. , Dye A. L. , McClure J. E. , Pyrak‐Nolte L. J. , Miller C. T. 
Published: June 2015

AbstractA model formulated in terms of both conservation and kinematic equations for phases and interfaces in two‐fluid‐phase flow in a porous medium system is summarized. Macroscale kinematic equations are derived as extensions of averaging theorems and do not rely on conservation principles. Models based on both conservation and kinematic equations can describe multiphase flow with varying fidelity. When only phase‐based equations are considered, a model similar in form to the traditional model for two‐fluid‐phase flow results. When interface conservation and kinematic equations are also included, a novel formulation results that naturally includes evolution equations that express dynamic changes in fluid saturations, pressures, the capillary pressure, and the fluid‐fluid interfacial area density in a two‐fluid‐system. This dynamic equation set is unique to this work, and the importance of the modeled physics is shown through both microfluidic experiments and high‐resolution lattice Boltzmann simulations. The validation work shows that the relaxation of interface distribution and shape toward an equilibrium state is a slow process relative to the time scale typically allowed for a system to approach an apparent equilibrium state based upon observations of fluid saturations and external pressure measurements. Consequently, most pressure‐saturation data intended to denote an equilibrium state are likely a sampling from a dynamic system undergoing changes of interfacial curvatures that are not typically monitored. The results confirm the importance of kinematic analysis in combination with conservation equations for faithful modeling of system physics.
Using in situ vertical displacements to characterize changes in moisture load
Authors: Murdoch Lawrence C. , Freeman Clay E. , Germanovich Leonid N. , Thrash Colby , DeWolf Scott 
Published: June 2015

AbstractChanges in soil moisture content alter the load on underlying material, and we have developed a technique for characterizing this effect by using an extensometer to measure the displacement caused by the load change. The extensometer is pushed into soil at depths of 5 m or more, and displacement between two anchors separated by ∼1.5 m is measured with a resolution of better than 0.01 μm (10−8 m). The instrument is sensitive to load changes at the ground surface within a radial distance that is roughly twice its depth, potentially providing a method for averaging changes in water content over hundreds of m2 or more. During a field trial at a site in South Carolina, compressive displacements in unsaturated saprolite were strongly correlated to rainfall with a calibration factor of 0.16 μm displacement per mm of rainfall ±0.002 μm/mm (R2 = 0.95). Estimates of the net change in water volume per unit area made using the calibration factor from rainfall were similar to independent estimates of evapotranspiration. The technique was affected by barometric pressure variations, but the sensitivity was less than expected and does not hinder meaningful application. A companion instrument demonstrated the displacement signal was repeatable.
Organocatalytic Aerobic Oxidation of α‐Fluoroalkyl Alcohols to Fluoroalkyl Ketones at Room Temperature
Authors: Kadoh Yoichi , Tashiro Masayuki , Oisaki Kounosuke , Kanai Motomu 
Published: June 2015

AbstractThe organocatalytic aerobic oxidation of electron‐deficient α‐fluoroalkyl alcohols at room temperature is described. The resulting fluoroalkyl ketones are versatile synthetic intermediates for a variety of fluorine‐containing molecules. This otherwise difficult transformation has now been accomplished by the reaction of α‐fluoroalkyl alcohols with N‐oxyl radicals, catalytically generated from 9‐azabicyclo[3.3.1]nonan‐3‐one N‐oxyl/nitrogen oxide (keto‐ABNO/NOx) and oxygen in acetic acid (AcOH), affording the corresponding fluoroalkyl ketones in high yield. This operationally simple reaction can be performed under mild conditions, and was applied to a wide range of alcohols (20 examples), thus demonstrating a high functional group tolerance. Moreover, a modified one‐pot protocol based on this method was able to convert an aldehyde to a trifluoromethyl ketone on a gram scale.magnified image
Boron Trifluoride‐Promoted Indium(III) Triflate‐Catalyzed Sequential One‐Pot Synthesis of (1,2‐Diaryl‐2‐oxoethyl)malonates from trans‐2‐Aryl‐3‐nitrocyclopropane‐1,1‐dicarboxylates and Activated Arenes
Authors: Selvi Thangavel , Srinivasan Kannupal 
Published: June 2015

AbstractA sequential one‐pot synthesis of Michael adducts of aroylmethylidenemalonates with activated aromatics is described. The method involves treatment of trans‐2‐aryl‐3‐nitro‐cyclopropane‐1,1‐dicarboxylates with boron trifluoride etherate to form aroylmethylidenemalonates in situ and then addition of activated aromatics such as indoles, carbazole, pyrrole, thiophenes, methoxybenzenes and benzodioxole followed by a catalytic amount of indium(III) triflate to the same reaction vessel. To prove the synthetic potential of the resulting Michael adducts, one of the adducts was transformed into a pharmaceutically interesting dihydropyridazinone derivative.magnified image
Synthesis of Benzofurans via Tandem Rhodium‐Catalyzed C(sp3)H Insertion and Copper‐Catalyzed Dehydrogenation
Authors: Li Lin , Xia Xiao‐Han , Wang Yong , Bora Pranjal P. , Kang Qiang 
Published: June 2015

AbstractA sequentially catalyzed cascade approach for the synthesis of benzofuran derivatives (up to 88% yield) from 1‐sulfonyl‐1,2,3‐triazoles has been developed. The cascade reaction involves sequential rhodium‐catalyzed C(sp3)H insertion and copper‐catalyzed aerobic oxidation. The method was made more convenient towards the synthesis of benzofurans starting from terminal alkynes via a one‐pot sequential copper‐catalyzed alkyne‐azide cycloaddition (CuAAC)/CH insertion/dehydrogenation cascade reaction. Moreover, the utility of the cascade approach was demonstrated in the synthesis of the indole framework.magnified image
Combining Electron‐Accepting Phthalocyanines and Nanorod‐like CuO Electrodes for p‐Type Dye‐Sensitized Solar Cells
Authors: Langmar Oliver , Ganivet Carolina R. , Lennert Annkatrin , Costa Rubén D. , de la Torre Gema , Torres Tomás , Guldi Dirk M. 
Published: June 2015

AbstractA route is reported for the synthesis of two electron‐accepting phthalocyanines featuring linkers with different lengths as sensitizers for p‐type dye‐sensitized solar cells (DSSCs). Importantly, our devices based on novel nanorod‐like CuO photocathodes showed high efficiencies of up to 0.191 %: the highest value reported to date for CuO‐based DSSCs.
Regiodivergent and Stereoselective Hydrosilylation of 1,3‐Disubstituted Allenes
Authors: Miller Zachary D. , Dorel Ruth , Montgomery John 
Published: June 2015

AbstractMethods for the highly stereoselective and regiodivergent hydrosilylation of 1,3‐disubstituted allenes have been developed. The synthesis of E allylsilanes is accomplished with palladium NHC catalysts, and trisubstituted Z alkenylsilanes are accessed with nickel NHC catalysts. Unsymmetrically substituted allenes are well tolerated with nickel catalysis and afford Z alkenylsilanes. Evidence for a plausible mechanism was obtained through an isotopic double‐labeling crossover study.
Mild functionalization of carbon nanotubes filled epoxy composites: Effect on electromagnetic interferences shielding effectiveness
Authors: Phan Chee Hong , Jaafar Mariatti , Koh Yin Hsian 
Published: June 2015

ABSTRACTThe effect of nitric acid mild functionalized multiwalled carbon nanotubes (MWCNTs) on electromagnetic interference (EMI) shielding effectiveness (SE) of epoxy composites was examined. MWCNTs were oxidized by concentrated nitric acid under reflux conditions, with different reaction times. The dispersion of MWCNTs after functionalization was improved due to the presence of oxygen functional groups on the nanotubes surface. Functionalization at 2 h exhibits the highest EMI SE and electrical conductivity of MWCNTs filled epoxy composites. However, EMI shielding performance of MWCNTs filled epoxy composite declined when the functionalization reaction time was prolonged. This was due to extensive damage on the MWCNT structure, as verified by a Raman spectroscope. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42557.
Controlled‐release drug carriers based hierarchical silica microtubes templated from cellulose acetate nanofibers
Authors: Jia Chengying , Song Junlong , Jin Yongcan , Rojas Orlando J. 
Published: June 2015

ABSTRACTWe report a facile method to synthesize hollow silica microtubes (SMTs) from electrospun cellulose acetate fiber precursors. Specific surface areas of up to 765 m2/g (Brunauer–Emmett–Teller) were measured for the SMTs, which had a typical wall thickness of ∼100 nm and submicron inner diameters. An average pore size of 4.6 nm and pore volume of 0.41 cm3/g were derived from Barrett–Joyner–Halenda fitting, whereas Horvath–Kawazoe pore size distribution analysis revealed microporous median pore size and maximum pore volume of 0.7 nm and 0.18 cm3/g, respectively. The as‐prepared SMTs featuring micro‐ and mesoporous structures in the walls where amino‐functionalized to facilitate a very high drug loading (15% by weight). Drug release profile revealed sustained release rates (79% of acetylsalicylic acid was released after 6 h). It is concluded that the high drug loading and sustained release resulted from the advantageous integration of SMTs' hollow structure and wall mesoporosity. © 2015 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 42562.
Towards an Understanding of Molecule Capture by the Antennae of Male Beetles Belonging to the Genus Rhipicera (Coleoptera, Rhipiceridae)
Authors: Ramsey Andrew , Houston Terry F. , Ball Alexander D. , Goral Tomasz , Barclay Maxwell V.L. , Cox Jonathan P.L. 
Published: June 2015

ABSTRACTWorking on the hypothesis that an important function of the lamellate antennae of adult male beetles belonging to the genus Rhipicera is to detect scent associated with female conspecifics, and using field observations, anatomical models derived from X‐ray microcomputed tomography, and scanning electron microscopy, we have investigated the behavioral, morphological, and morphometric factors that may influence molecule capture by these antennae. We found that male beetles fly upwind in a zigzag manner, or face upwind when perching, behavior consistent with an animal that is tracking scent. Furthermore, the ultrastructure of the male and female antennae, like their gross morphology, is sexually dimorphic, with male antennae possessing many more of a particular type of receptor—the sensillum placodeum—than their female counterparts (approximately 30,000 vs. 100 per antenna, respectively). Based on this disparity, we assume that the sensilla placodea on the male antennae are responsible for detecting scent associated with female Rhipicera beetles. Molecule capture by male antennae in their alert, fanned states is likely to be favoured by: (a) male beetles adopting prominent, upright positions on high points when searching for scent; (b) the partitioning of antennae into many small segments; (c) antennal morphometry (height, width, outline area, total surface area, leakiness, and narrow channels); (d) the location of the sensilla placodea where they are most likely to encounter odorant molecules; and (e) well dispersed sensilla placodea. The molecule‐capturing ability of male Rhipicera antennae may be similar to that of the pectinate antennae of certain male moths. Anat Rec, 298:1519–1534, 2015. © 2015 Wiley Periodicals, Inc.
3D Reconstruction of Buried Structures from Magnetic, Electromagnetic and ERT Data: Example from the Archaeological Site of Phaistos (Crete, Greece)
Authors: Di Maio Rosa , La Manna Mauro , Piegari Ester 
Published: June 2015

AbstractA multi‐methodological geophysical prospecting was performed in a survey area of the archaeological Phaistos site on the Greek island of Crete, as part of an international research project aimed at investigating the less excavated hills of Phaistos and the underlying plateau. The article provides an assessment of the resolution of the chosen techniques for non‐destructive testing of buried ancient structures in the geological landscape of Phaistos. The magnetic and electromagnetic surveys clearly detected anomalies related to human activity, some of which were subsequently defined in detail by resistivity tomography imaging. In particular, variations of the observed electrical and magnetic parameters perfectly correlate to a wall structure made of calcareous material, which has been brought to light by subsequent excavations that unearthed large sectors of a fortification in a double curtain wall, chronologically consistent with the historical sources about the destruction of Phaistos in 150 bc. Copyright © 2015 John Wiley & Sons, Ltd.
The Discovery of an Ancient Greek Vineyard
Authors: Smekalova Tatiana N. , Bevan Bruce W. , Chudin Andrei V. , Garipov Alexander S. 
Published: June 2015

AbstractRelatively few geophysical surveys have shown how buried traces of agricultural fields can be revealed. An ancient Greek vineyard on the Crimean peninsula was first suggested in a satellite photograph; however, it was discovered only with a magnetic survey. This survey found a 5.7‐ha field that is crossed by about 80 buried stone walls that are parallel and spaced by 2.6 m; this pattern is found only in the vineyard. Later excavations revealed underground walls in this vineyard.The magnetic survey also detected simple magnetic anomalies at three of the four corners of the vineyard. Excavations found that these anomalies are caused by pits that were dug by the ancient Greeks into bedrock to a depth of 2.5 m; the purpose of these pits is not known.The magnetic properties of soil and stone were measured in the excavations, and the magnetic anomalies of the features were calculated. These calculations agree with the measurements, and this means that the entire source of the anomalies was discovered. The interpretation of the magnetic map was adaptive, and it improved as excavations added more information.The archaeological importance of the Ortli vineyard is described along with the efficient procedures that allowed its discovery and mapping. Using the same techniques that were applied at Ortli, another ancient Greek vineyard and farmhouse was later found 1.5 km away. This vineyard has dimensions that are 25% larger than those of the first vineyard. Copyright © 2015 John Wiley & Sons, Ltd.
Fourth‐derivative synchronous spectrofluorimetry and HPLC with fluorescence detection as two analytical techniques for the simultaneous determination of itopride and domperidone
Authors: Ibrahim Fawzia , Nasr Jenny Jeehan 
Published: June 2015

ABSTRACTTwo simple, rapid and sensitive methods, namely, fourth‐derivative synchronous spectrofluorimetry (method I) and HPLC with fluorescence detection (method II) were developed for the simultaneous analysis of a binary mixture of itopride HCl (ITP) and domperidone (DOM) without prior separation. The first method was based on measuring the fourth derivative of the synchronous fluorescence spectra of the two drugs at Δλ = 40 nm in methanol. The different experimental parameters affecting the synchronous fluorescence of the studied drugs were carefully optimized. Chromatographic separation was performed in < 6.0 min using a RP C18 column (250 mm × 4.6 mm i.d., 5 µm particle size) with fluorescence detection at 344 nm after excitation at 285 nm. A mobile phase composed of a mixture of 0.02 M phosphate buffer with acetonitrile in a ratio of 55 : 45, pH 4.5, was used at a flow rate of 1 mL/min. Linearity ranges were found to be 0.1–2 µg/mL for ITP in both methods, whereas those for DOM were found to be 0.08–2 and 0.05–1.5 µg/mL in methods I and II, respectively. The proposed methods were successfully applied for the determination of the studied drugs in synthetic mixtures and laboratory‐prepared tablets. Copyright © 2015 John Wiley & Sons, Ltd.
Simultaneous and sensitive detection of dual DNA targets via quantum dot‐assembled amplification labels
Authors: Cui Hongyan , Song Wenqing , Cao Zhijuan , Lu Jianzhong 
Published: June 2015

AbstractWe describe a signal amplification assay for the simultaneous detection of HIV‐1 and HIV‐2 via a quantum dot (QD) layer‐by‐layer assembled polystyrene microsphere (PS) composite in a homogeneous format. The crucial point of this composite is the core–shell system. PS is utilized as the core and QDs as the shell. Based on the high affinity of streptavidin and biotin, QDs are assembled layer‐by‐layer on the surface of the PS as amplification labels. Biotinylated reporter probe is combined with the PS–QDs conjugate and then hybridized with target DNA immobilized on the surface of a 96‐well plate. Using this approach, each target DNA corresponds to a large number of QDs and the fluorescence signal is greatly enhanced. Two QD colors (605 and 655 nm) are used to detect dual‐target DNAs simultaneously. Taking advantage of the enzyme‐free reaction and high sensitivity, this PS–QD‐based sensor can be used in simple ‘mix and detection’ assays. Our results show that this technology has potential application in rapid point‐of‐care testing, gene expression studies, high‐throughput screening and clinical diagnostics. Copyright © 2015 John Wiley & Sons, Ltd.