bluuebunny/crossref_metadata_2025 huggingface dataset:
Simulation of root water uptake under consideration of nonequilibrium dynamics in the rhizosphere
Authors: Kroener Eva , Zarebanadkouki Mohsen , Bittelli Marco , Carminati Andrea
Published: June 2016

The narrow region of soil around roots, the so‐called rhizosphere, defers in its hydraulic properties from the bulk soil. The rhizosphere hydraulic properties primarily depend on the drying and wetting rate of mucilage, a polymeric gel exuded by plant roots. Under equilibrium conditions mucilage increases the water holding capacity. Upon drying mucilage turns hydrophobic and makes the rhizosphere temporarily water repellent. There are several models of root water uptake, from analytical models of water flow to a single root to complex numerical models that consider the root architecture. Most of these models, however, do not account for the specific hydraulic properties of the rhizosphere. Here we describe a single‐root model that includes the altered hydraulic properties of the rhizosphere due to mucilage exudation. We use the model to reproduce existing experiments reporting unexpected and puzzling hysteresis in the rhizosphere, which could not be explained under the assumption of homogeneous hydraulic properties. In our model the hydraulic properties depend on the concentration of mucilage. This enables a continuous transition from the bulk soil to the root surface. We assumed that: (a) mucilage increases the water holding capacity in equilibrium conditions, (b) hydrophobicity, swelling and shrinking of mucilage cause a nonequilibrium relation between water content and water potential and (c) mucilage reduces the mobility of water molecules in the liquid phase resulting in a lower hydraulic conductivity at a given water content. Our model reproduces well the experiments and suggests that mucilage softens drought stress in plants during severe drying events.
Widespread effusive volcanism on Mercury likely ended by about 3.5 Ga
Authors: Byrne Paul K. , Ostrach Lillian R. , Fassett Caleb I. , Chapman Clark R. , Denevi Brett W. , Evans Alexander J. , Klimczak Christian , Banks Maria E. , Head James W. , Solomon Sean C.
Published: June 2016

Crater size–frequency analyses have shown that the largest volcanic plains deposits on Mercury were emplaced around 3.7 Ga, as determined with recent model production function chronologies for impact crater formation on that planet. To test the hypothesis that all major smooth plains on Mercury were emplaced by about that time, we determined crater size–frequency distributions for the nine next‐largest deposits, which we interpret also as volcanic. Our crater density measurements are consistent with those of the largest areas of smooth plains on the planet. Model ages based on recent crater production rate estimates for Mercury imply that the main phase of plains volcanism on Mercury had ended by ~3.5 Ga, with only small‐scale volcanism enduring beyond that time. Cessation of widespread effusive volcanism is attributable to interior cooling and contraction of the innermost planet.
What would it take to achieve the Paris temperature targets?
Authors: Sanderson Benjamin M. , O'Neill Brian C. , Tebaldi Claudia
Published: June 2016

The 2015 Paris Agreement aims to limit warming to 2 or 1.5°C above preindustrial level, although combined Intended Nationally Determined Contributions (INDCs) are likely insufficient to achieve these targets. We propose a set of idealized emission pathways consistent with the targets. If countries reduce emissions in line with their INDCs, the 2°C threshold could be avoided only if net zero greenhouse gas emissions (GHGEs) are achieved by 2085 and late century negative emissions are considerably in excess of those assumed in Representative Concentration Pathway (RCP) 2.6 (net −5 Gt CO2/yr, compared with −1.5 Gt CO2/yr in RCP2.6). More aggressive near‐term reductions would allow 2°C to be avoided with less end‐of‐century carbon removal capacity. A 10% cut in GHGEs by 2030 (relative to 2015) could likely achieve 2°C with RCP2.6 level negative emissions. The 1.5°C target requires GHGEs to be reduced by almost a third by 2030 and net zero by 2050, while a 50 year overshoot of 1.5°C allows net zero GHGEs by 2060.
Experimental evidence for shallow, slow‐moving landslides activated by a decrease in ground temperature
Authors: Shibasaki Tatsuya , Matsuura Sumio , Okamoto Takashi
Published: June 2016

In order to understand the trigger mechanism of slow‐moving landslides occurring in the early cold season from late autumn to winter, we investigated the effect of temperature on the shear strength of slip surface soils. Displacement‐controlled and shear stress‐controlled box shear experiments were performed on undisturbed slip zone soils under residual strength conditions. Test results conducted at temperatures from 9 to 25°C showed remarkable shear strength reductions with decreasing temperature. Creep‐like slow shear displacements were induced by a decrease in temperature. These temperature‐dependent shear behaviors are attributed to the rheological properties of hydrous smectite that dominantly compose the soil material along the failure surface. Our experimental results imply that ground temperature conditions influence slope instability, especially for shallow landslides occurring in smectite‐bearing rock areas.
An inverse method for estimating thickness and volume with time of a thin CO2‐filled layer at the Sleipner Field, North Sea
Authors: Cowton L. R. , Neufeld J. A. , White N. J. , Bickle M. J. , White J. C. , Chadwick R. A.
Published: June 2016

Migration of CO2 through storage reservoirs can be monitored using time lapse seismic reflection surveys. At the Sleipner Field, injected CO2 is distributed throughout nine layers within the reservoir. These layers are too thin to be seismically resolvable by direct measurement of the separation between reflections from the top and bottom of each layer. Here we develop and apply an inverse method for measuring thickness changes of the shallowest layer. Our approach combines differences in traveltime down to a specific reflection together with amplitude measurements to determine layer thicknesses from time lapse surveys. A series of synthetic forward models were used to test the robustness of our inverse approach and to quantify uncertainties. In the absence of ambient noise, this approach can unambiguously resolve layer thickness. If a realistic ambient noise distribution is included, layer thicknesses of 1–6 m are accurately retrieved with an uncertainty of ±0.5 m. We used this approach to generate a thickness map of the shallowest layer. The fidelity of this result was tested using measurements of layer thickness determined from the 2010 broadband seismic survey. The calculated volume of CO2 within the shallowest layer increases at a rate that is quadratic in time, despite an approximately constant injection rate into the base of the reservoir. This result is consistent with a diminished growth rate of the areal extent of underlying layers. Finally, the relationship between caprock topography and layer thickness is explored and potential migration pathways that charge this layer are identified.
Predictability of wind‐induced sea surface transport in coastal areas
Authors: Cucco A. , Quattrocchi G. , Satta A. , Antognarelli F. , De Biasio F. , Cadau E. , Umgiesser G. , Zecchetto S.
Published: June 2016

In this work we investigated the predictability of the wind‐induced sea surface transport in coastal areas. The wind fields predicted by two state‐of‐the‐art meteorological models, namely ECMWF and SKIRON, were used as forcing for a hydrodynamic and particle‐tracking model applied to reproduce a set of observed drifters trajectories in a coastal area of the Mediterranean Sea. A set of anemometric data derived by in situ measurements were also adopted as model forcing to reproduce the observed drifter paths. This approach provided a baseline that was used as a reference for evaluating the effects of the predicted wind accuracy on the numerical model solution. The accuracy of the simulation results obtained using, as model forcing, the observed wind data was fair and suitable for most of the operational oceanographic purposes. It decreased when using the wind data predicted by the two meteorological models. In particular, the results obtained using ECMWF data were about 3 times more accurate than the ones obtained using SKIRON ones. The uncertainties were strongly dependent on the range of observed wind speed classes with a different behavior depending on the type of adopted wind data. Finally, the amplification of the errors in predicting the sea surface transport generated by the inaccuracies of the predicted wind fields was quantified.
Vertical distribution of buoyant Microcystis blooms in a Lagrangian particle tracking model for short‐term forecasts in Lake Erie
Authors: Rowe M. D. , Anderson E. J. , Wynne T. T. , Stumpf R. P. , Fanslow D. L. , Kijanka K. , Vanderploeg H. A. , Strickler J. R. , Davis T. W.
Published: June 2016

Cyanobacterial harmful algal blooms (CHABs) are a problem in western Lake Erie, and in eutrophic fresh waters worldwide. Western Lake Erie is a large (3000 km2), shallow (8 m mean depth), freshwater system. CHABs occur from July to October, when stratification is intermittent in response to wind and surface heating or cooling (polymictic). Existing forecast models give the present location and extent of CHABs from satellite imagery, then predict two‐dimensional (surface) CHAB movement in response to meteorology. In this study, we simulated vertical distribution of buoyant Microcystis colonies, and 3‐D advection, using a Lagrangian particle model forced by currents and turbulent diffusivity from the Finite Volume Community Ocean Model (FVCOM). We estimated the frequency distribution of Microcystis colony buoyant velocity from measured size distributions and buoyant velocities. We evaluated several random‐walk numerical schemes to efficiently minimize particle accumulation artifacts. We selected the Milstein scheme, with linear interpolation of the diffusivity profile in place of cubic splines, and varied the time step at each particle and step based on the curvature of the local diffusivity profile to ensure that the Visser time step criterion was satisfied. Inclusion of vertical mixing with buoyancy significantly improved model skill statistics compared to an advection‐only model, and showed greater skill than a persistence forecast through simulation day 6, in a series of 26 hindcast simulations from 2011. The simulations and in situ observations show the importance of subtle thermal structure, typical of a polymictic lake, along with buoyancy in determining vertical and horizontal distribution of Microcystis.
Half order plus time delay (HOPTD) models to tune PI controllers
Authors: Lee Jietae , Lee Yongjeh , Yang Dae Ryook , Edgar Thomas F.
Published: June 2016

Methods based on the first‐order plus time delay (FOPTD) model are very popular for tuning proportional‐integral (PI) controllers. The FOPTD model‐based methods are simple and their utility has been proved with many successful applications to a wide range of processes in practice. However, even for some overdamped processes where the FOPTD model seems to be applied successfully, these empirical FOPTD model‐based methods can fail to provide stable tuning results. To remove these drawbacks, a PI controller tuning method based on half‐order plus time delay (HOPTD) model is proposed. Because FOPTD model‐based methods can be applied to higher order processes, the proposed HOPTD model‐based method can be applied to higher order processes as well. It does not require any additional process information compared to the FOPTD model‐based method and hence can be used for overdamped processes in practice, complementing the traditional FOPTD model‐based methods. © 2016 American Institute of Chemical Engineers AIChE J, 63: 601–609, 2017
Quantitative evaluation of mass transfer near the edge of porous media by absorption photometry
Authors: Tanikoshi Taiki , Otomo Ryoko , Harada Shusaku
Published: June 2016

The intensive investigation of mass transfer near the entrance (edge) of porous media by quantification of the surrounding concentration field has been performed. We have adopted a noninvasive and real‐time system based on light absorption photometry for measurement of the concentration field in a quasi‐two dimensional cell. This system is, in principle, applicable to the measurement of various substances due to the generality of light absorption. This measurement system was applied to a simple model of the gravity‐driven transport of a substance in a fluid near the edge of a porous medium in the presence of a reaction at the surface. The temporal variation of the complicated concentration field is appropriately captured with a spatial resolution of several tens of micrometers to millimeters. Quantitative analyses revealed that the geometry of the porous edge considerably affects the convection flow and invasion of substances into the medium. © 2016 American Institute of Chemical Engineers AIChE J, 63: 823–833, 2017
Population variation of LIN28B in the Mediterranean: Novel markers for microgeographic discrimination
Authors: Álvarez‐Álvarez Miguel M. , Carreras‐Torres Robert , Zanetti Daniela , Vegas Esteban , Moral Pedro
Published: June 2016

Objectives

The aim of this study is to determine whether the LIN28B gene is differentially distributed in the Mediterranean region through the analysis of the allele distribution of three single nucleotide polymorphisms (SNPs), namely rs7759938, rs314277, and rs221639, in 24 populations. These SNPs have been recently related to the age at menarche, pubertal height growth, peripubertal body mass index, levels of prenatal testosterone exposure, and cancer survival.

Methods

A total of 1,197 DNA samples were genotyped. The allele frequencies were used to determine the relationship between populations, with data from the 1000 Genomes Project being used for external comparisons. The genotype distributions and the population structure between populations and groups of populations were determined.

Results

The population results indicate a significant degree of variation (FST = 0.043, P < 0.0001). Allele frequencies show significant differences among populations. A hierarchical variance analysis is consistent with a primary differentiation between populations on the North and South coasts of the Mediterranean. This difference is especially evident in the unexpected distribution of the SNP rs221639, which shows one of the highest FST (11.5%, P < 0.0001) values described in the Mediterranean region thus far.

Conclusion

The population differentiation and the structuring of the genetic variance, in agreement with previous studies, indicate that the SNPs in question are good tools for the study of human populations, even at a microgeographic level. Am. J. Hum. Biol. 28:905–912, 2016. © 2016Wiley Periodicals, Inc.
An analysis of fatal and non‐fatal injuries and injury severity factors among electric power industry workers
Authors: Fordyce Tiffani A. , Leonhard Megan J. , Watson Heather N. , Mezei Gabor , Vergara Ximena P. , Krishen Lovely
Published: June 2016

Background

The electric power industry represents a unique subset of the U.S. workforce. We aimed to evaluate the relationships between occupational category, nature of injury, and injury severity among electric power industry workers.

Methods

The Occupational Health and Safety Database (1995–2013) was used to calculate injury rates, assess patterns of injury severity, and identify at‐risk occupations in this population.

Results

Over the surveillance period, a total of 63,193 injuries were reported. Overall, and severe injury rates were 3.20 and 0.52 per 100 employee‐years, respectively. The fatal injury rate was 3.29 per 100,000 employee‐years. Line workers experienced the highest risk for fatal injuries and second highest for non‐fatal severe injuries, following meter readers. The most severe non‐fatal injuries were hernia and rupture; multiple injuries; and CTD/RSI. Fatal injuries were most commonly associated with vehicle collisions and contact with electric current.

Conclusions

Industry specific surveillance and interventions tailored to high‐risk occupations are needed to further reduce severe injuries in this population. Am. J. Ind. Med. 59:948–958, 2016. © 2016 Wiley Periodicals, Inc.
Genetic variation in the endocannabinoid system and response to Cognitive Behavior Therapy for child anxiety disorders
Authors: Lester Kathryn J. , Coleman Jonathan R. I. , Roberts Susanna , Keers Robert , Breen Gerome , Bögels Susan , Creswell Cathy , Hudson Jennifer L. , McKinnon Anna , Nauta Maaike , Rapee Ronald M. , Schneider Silvia , Silverman Wendy K. , Thastum Mikael , Waite Polly , Wergeland Gro Janne H. , Eley Thalia C.
Published: June 2016

Extinction learning is an important mechanism in the successful psychological treatment of anxiety. Individual differences in response and relapse following Cognitive Behavior Therapy may in part be explained by variability in the ease with which fears are extinguished or the vulnerability of these fears to re‐emerge. Given the role of the endocannabinoid system in fear extinction, this study investigates whether genetic variation in the endocannabinoid system explains individual differences in response to CBT. Children (N = 1,309) with a primary anxiety disorder diagnosis were recruited. We investigated the relationship between variation in the CNR1, CNR2, and FAAH genes and change in primary anxiety disorder severity between pre‐ and post‐treatment and during the follow‐up period in the full sample and a subset with fear‐based anxiety disorder diagnoses. Change in symptom severity during active treatment was nominally associated (P < 0.05) with two SNPs. During the follow‐up period, five SNPs were nominally associated with a poorer treatment response (rs806365 [CNR1]; rs2501431 [CNR2]; rs2070956 [CNR2]; rs7769940 [CNR1]; rs2209172 [FAAH]) and one with a more favorable response (rs6928813 [CNR1]). Within the fear‐based subset, the effect of rs806365 survived multiple testing corrections (P < 0.0016). We found very limited evidence for an association between variants in endocannabinoid system genes and treatment response once multiple testing corrections were applied. Larger, more homogenous cohorts are needed to allow the identification of variants of small but statistically significant effect and to estimate effect sizes for these variants with greater precision in order to determine their potential clinical utility. © 2016 The Authors. American Journal of Medical Genetics Part B: Neuropsychiatric Genetics Published by Wiley Periodicals, Inc.
Maximum likelihood estimate of life expectancy in the prehistoric Jomon: Canine pulp volume reduction suggests a longer life expectancy than previously thought
Authors: Sasaki Tomohiko , Kondo Osamu
Published: June 2016

Recent theoretical progress potentially refutes past claims that paleodemographic estimations are flawed by statistical problems, including age mimicry and sample bias due to differential preservation. The life expectancy at age 15 of the Jomon period prehistoric populace in Japan was initially estimated to have been ∼16 years while a more recent analysis suggested 31.5 years. In this study, we provide alternative results based on a new methodology. The material comprises 234 mandibular canines from Jomon period skeletal remains and a reference sample of 363 mandibular canines of recent‐modern Japanese. Dental pulp reduction is used as the age‐indicator, which because of tooth durability is presumed to minimize the effect of differential preservation. Maximum likelihood estimation, which theoretically avoids age mimicry, was applied. Our methods also adjusted for the known pulp volume reduction rate among recent‐modern Japanese to provide a better fit for observations in the Jomon period sample. Without adjustment for the known rate in pulp volume reduction, estimates of Jomon life expectancy at age 15 were dubiously long. However, when the rate was adjusted, the estimate results in a value that falls within the range of modern hunter‐gatherers, with significantly better fit to the observations. The rate‐adjusted result of 32.2 years more likely represents the true life expectancy of the Jomon people at age 15, than the result without adjustment. Considering ∼7% rate of antemortem loss of the mandibular canine observed in our Jomon period sample, actual life expectancy at age 15 may have been as high as ∼35.3 years.
Encapsulating Palladium Nanoparticles Inside Mesoporous MFI Zeolite Nanocrystals for Shape‐Selective Catalysis
Authors: Cui Tian‐Lu , Ke Wen‐Yu , Zhang Wen‐Bei , Wang Hong‐Hui , Li Xin‐Hao , Chen Jie‐Sheng
Published: June 2016

Pd nanoparticles were successfully encapsulated inside mesoporous silicalite‐1 nanocrystals (Pd@mnc‐S1) by a one‐pot method. The as‐synthesized Pd@mnc‐S1 with excellent stability functioned as an active and reusable heterogeneous catalyst. The unique porosity and nanostructure of silicalite‐1 crystals endowed the Pd@mnc‐S1 material general shape‐selectivity for various catalytic reactions, including selective hydrogenation, oxidation, and carbon–carbon coupling reactions.
Luminescent Gold Nanoparticles with Size‐Independent Emission
Authors: Liu Jinbin , Duchesne Paul N. , Yu Mengxiao , Jiang Xingya , Ning Xuhui , Vinluan Rodrigo D. , Zhang Peng , Zheng Jie
Published: June 2016

Size‐independent emission has been widely observed for ultrasmall thiolated gold nanoparticles (AuNPs) but our understanding of the photoluminescence mechanisms of noble metals on the nanoscale has remained limited. Herein, we report how the emission wavelength of a AuNP and the local binding geometry of a thiolate ligand (glutathione) on the AuNP are correlated, as these AuNPs emit at different wavelengths in spite of their identical size (ca. 2.5 nm). By using circular dichroism, X‐ray absorption, and fluorescence spectroscopy, we found that a high Au−S coordination number (CN) and a high surface coverage resulted in strong AuI–ligand charge transfer, a chiral conformation, and 600 nm emission, whereas a low Au−S CN and a low surface coverage led to weak charge transfer, an achiral conformation, and 810 nm emission. These two size‐independent emissions can be integrated into one single 2.5 nm AuNP by fine‐tuning of the surface coverage; a ratiometric pH response was then observed owing to strong energy transfer between two emission centers, opening up new possibilities for the design of ultrasmall ratiometric pH nanoindicators.
Coordinatively Unsaturated Lanthanide(III) Helicates: Luminescence Sensors for Adenosine Monophosphate in Aqueous Media
Authors: Sahoo Jashobanta , Arunachalam Rajendran , Subramanian Palani S. , Suresh Eringathodi , Valkonen Arto , Rissanen Kari , Albrecht Markus
Published: June 2016

Coordinatively unsaturated double‐stranded helicates [(H2L)2Eu2(NO3)2(H2O)4](NO3)4, [(H2L)2Tb2(H2O)6](NO3)6, and [(H2L)2Tb2(H2O)6]Cl6 (H2L=butanedioicacid‐1,4‐bis[2‐(2‐pyridinylmethylene)hydrazide]) are easily obtained by self‐assembly from the ligand and the corresponding lanthanide(III) salts. The complexes are characterized by X‐ray crystallography showing the helical arrangement of the ligands. Co‐ligands at the metal ions can be easily substituted by appropriate anions. A specific luminescence response of AMP in presence of ADP, ATP, and other anions is observed. Specificity is assigned to the perfect size match of AMP to bridge the two metal centers and to replace quenching co‐ligands in the coordination sphere.
A Mixed‐Ligand Approach for a Gigantic and Hollow Heterometallic Cage {Ni64RE96} for Gas Separation and Magnetic Cooling Applications
Authors: Chen Wei‐Peng , Liao Pei‐Qin , Yu Youzhu , Zheng Zhiping , Chen Xiao‐Ming , Zheng Yan‐Zhen
Published: June 2016

Nanosized aggregations of metal ions shielded by organic ligands possessing both exquisite structural aesthetics and intriguing properties are fundamentally interesting. Three isostructural gigantic transition‐metal–rare‐earth heterometallic coordination cages are reported, abbreviated as {Ni64RE96} (RE=Gd, Dy, and Y) and obtained by a mixed‐ligand approach, each possessing a cuboidal framework made of 160 metal ions and a nanosized spherical cavity in the center. Along with the structural novelty, these hollow cages show highly selective adsorptions for CO2 over CH4 or N2 at ambient temperatures. Moreover, the gadolinium analogue exhibits large magnetocaloric effect at ultralow temperatures.
A green approach for the synthesis of 2‐oxazolidinones using gold(I) complex immobilized on KCC‐1 as nanocatalyst at room temperature
Authors: Sadeghzadeh Seyed Mohsen
Published: June 2016

A novel gold(I)‐containing ionic liquid‐based KCC‐1 catalyst was applied for the cyclization of propargylic amines with CO2 to provide 2‐oxazolidinones. High catalytic activity and ease of recovery from the reaction mixture using an external magnet, and several recycle runs without significant loss in performance are additional eco‐friendly attributes of this catalytic system. Copyright © 2016 John Wiley & Sons, Ltd.
Slightly crosslinked polyurethane with Diels–Alder adducts from trimethylolpropane
Authors: Du Pengfei , Jia Haiyan , Chen Qinghua , Zheng Zhen , Wang Xinling , Chen Denglong
Published: June 2016

Diels–Alder (DA) reactions between furan and maleimide have been widely applied in thermally remendable polymeric materials. Crosslinked polyurethane with DA adducts exhibited much better mechanical properties than linear polyurethane with DA adducts. However, the highly crosslinked polyurethane needs a higher temperature and a longer healing time. This will increase the possibility of side reactions proceeding during the healing procedure. In this paper, slightly crosslinked polyurethane with DA adducts was synthesized by incorporating trimethylolpropane into linear polyurethane with DA adducts. The structure of the intermediate and final products was characterized by Fourier transform infrared spectroscopy, 1H‐NMR, and differential scanning calorimetry, confirming that the synthesizing process proceeded successfully. The images from the polarizing optical microscope demonstrated that the final product with slight crosslinking needed less time and a lower healing temperature to complete the healing procedure. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2016, 133, 43971.
A Chiral Hemiporphyrazine Derivative: Synthesis and Chiroptical Properties
Authors: Wu Yanping , Gai Lizhi , Xiao Xuqiong , Lu Hua , Li Zhifang , Mack John , Harris Jessica , Nyokong Tebello , Shen Zhen
Published: June 2016

The synthesis of an optically active hemiporphyrazine with chiral binaphthyl substituents (1) is reported, providing the first example of the incorporation of an intrinsically chiral moiety into the macrocyclic core of a hemiporphyrazine analogue. A negative circular dichroism (CD) signal is observed in the 325–450 nm region of the CD spectrum of (S,S)‐1, while mainly positive bands are observed in the 220–325 nm region. Mirror symmetry is observed across the entire wavelength range of the CD spectra of (R,R)‐1and (S,S)‐1. An irreversible one‐electron oxidation wave with an onset potential at 1.07 V is observed by cyclic voltammetry, along with a reversible one‐electron reduction wave at −0.85 V. Density functional calculations reproduce the experimentally observed data and trends, and provide further insight into the nature of the electronic transitions.
Surface‐Bound Cucurbit[8]uril Catenanes on Magnetic Nanoparticles Exhibiting Molecular Recognition
Authors: Ren Xiaohe , Wu Yuchao , Clarke David E. , Liu Ji , Wu Guanglu , Scherman Oren A.
Published: June 2016

We demonstrate the preparation of surface‐bound cucurbit[8]uril (CB[8]) catenanes on silica nanoparticles (NPs), where CB[8] was employed as a tethered supramolecular “handcuff” to selectively capture target guest molecules. In this catenane, CB[8] was threaded onto a methyl viologen (MV2+) axle and immobilized onto silica NPs. The formation of CB[8] catenanes on NPs were confirmed by UV/Vis titration experiments and lithographic characterization, demonstrating a high density of CB[8] on the silica NPs surface, 0.56 nm−2. This CB[8] catenane system exhibits specific molecular recognition towards certain aromatic molecules such as perylene bis(diimide), naphthol and aromatic amino acids, and thus it can act as a nanoscale molecular receptor for target guests. Furthermore, we also demonstrate its use as an efficient and recyclable nano‐platform for peptide separation. By embedding magnetic NPs inside silica NPs, separation could be achieved by simply applying an external magnetic field. Moreover, the peptides captured by the catenanes could be released by reversible single‐electron reduction of MV2+. The entire process demonstrated high recoverability.
Follow‐up spectroscopic observations of HD 107148 B: A new white dwarf companion of an exoplanet host star
Authors: Mugrauer M. , Dinçel B.
Published: June 2016

We report on our follow‐up spectroscopy of HD 1071478 B, a recently detected faint co‐moving companion of the exoplanet host star HD 107148 A. The companion is separated from its primary star by about 35″ (or 1790 AU of projected separation) and its optical and near infrared photometry is consistent with a white dwarf, located at the distance of HD 107148 A. In order to confirm the white dwarf nature of the co‐moving companion, we obtained follow‐up spectroscopic observations of HD 107148 B with CAFOS at the CAHA 2.2 m telescope. According to our CAFOS spectroscopy HD 107148 B is a DA white dwarf with an effective temperature in the range between 5900 and 6400K. The properties of HD 107148 B can further be constrained with the derived effective temperature and the known visual and infrared photometry of the companion, using evolutionary models of DA white dwarfs. We obtain for HD 107148 B a mass of 0.56 ± 0.05 M⊙, a luminosity of (2.0 ± 0.2) × 10–4 L⊙, log g [cm s–2]) = 7.95 ± 0.09, and a cooling age of 2100 ± 270 Myr. With its white dwarf companion the exoplanet host star HD 107148 A forms an evolved stellar system, which hosts at least one exoplanet. So far, only few of these evolved systems are known, which represent only about 5 % of all known exoplanet host multiple stellar systems. HD 107148 B is the second confirmed white dwarf companion of an exoplanet host star with a projected separation to its primary star of more than 1000 AU. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Discovery of a companion at the brown dwarf limit to the solar‐type star Gliese 29
Authors: Chini R. , Fuhrmann K. , Pozo Nuñez F. , Ramolla M. , Kaderhandt L. , Niedworok N. , Hodapp K.‐W.
Published: June 2016

Gliese 29 is a 7 to 8 Gyr old, southern Population I turnoff star with a large proper motion of 1″/yr. Using recent direct imaging observations with the 0.8 m Infrared Imaging System (IRIS) of the Universitätssternwarte Bochum near Cerro Armazones in Chile, we demonstrate that the faint source 2MASS J00402651–5927168 at a projected angular separation ρ = 6.″35 is a common‐proper‐motion companion to Gl 29. Provided this source is not part of a further subsystem, the IRIS J ‐ and Ks‐band photometry either implies a spectral type of about L2, based on its absolute magnitude, or an approximate mass MB ≃ 0.077 M⊙, suggesting that it may even be a brown dwarf. Assuming a face‐on circular orbit this faint companion orbits Gl 29 in 1880 years. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Gemini J ‐band observations of RX J0806.4–4123
Authors: Posselt B. , Luhman K. L.
Published: June 2016

The detection of near‐infrared (NIR) excess at the position of a star can indicate either a substellar companion or a disk around the respective star. In this work we probed whether a 2.5σ H ‐band flux enhancement at the position of the isolated neutron star RX J0806.4–4123 can be confirmed at another NIR wavelength. We observed RXJ0806.4–4123 in the J ‐band with Gemini South equipped with FLAMINGOS‐2. There was no significant detection of a J ‐band source at the neutron star position. However, similarly to the H ‐band we found a very faint (1.4σ) flux enhancement with a nominal magnitude of J = 24.8 ± 0.5. The overall NIR‐detection significance is 3.1σ. If real, this emission is too bright to come from the neutron star alone. Deeper near‐infrared observations are necessary to confirm or refute the potential NIR excess. The confirmation of such NIR excess could imply that there is a substellar companion or a disk around RXJ0806.4–4123. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Excess B‐modes extracted from the Planck polarization maps
Authors: Nørgaard‐Nielsen H. U.
Published: June 2016

One of the main obstacles for extracting the Cosmic Microwave Background (CMB) from mm/submm observations is the pollution from the main Galactic components: synchrotron, free‐free and thermal dust emission. The feasibility of using simple neural networks to extract CMB has been demonstrated on both temperature and polarization data obtained by the WMAP satellite. The main goal of this paper is to demonstrate the feasibility of neural networks for extracting the CMB signal from the Planck polarization data with high precision. Both auto‐correlation and cross‐correlation power spectra within a mask covering about 63 % of the sky have been used together with a “high pass filter” in order to minimize the influence of the remaining systematic errors in the Planck Q and U maps. Using the Planck 2015 released polarization maps, a BB power spectrum have been extracted by Multilayer Perceptron neural networks. This spectrum contains a bright feature with signal to noise ratios 4.5 within 200 ≪ l ≪ 250. The spectrum is significantly brighter than the BICEP2 2015 spectrum, with a spectral behaviour quite different from the “canonical” models (weak lensing plus B‐modes spectra with different tensor to scalar ratios). The feasibility of the neural network to remove the residual systematics from the available Planck polarization data to a high level has been demonstrated. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
Light‐curve solutions of 20 ecipsing Kepler binaries, most of them with pronounced spot and flare activity
Authors: Kjurkchieva D. , Atanasova T. , Dimitrov D.
Published: June 2016

We carried out light curve solutions of the Kepler light curves of twenty detached eclipsing binaries with circular orbits and determined the orbital inclinations, temperatures. relative radii and luminosities of their components. We studied the quality of the solutions with respect to the adopted limb‐darkening law and its coefficients. The detailed tracing of the numerous and uninterrupted data of our targets gave us an unique possibility to detect and learn their spot and flare activity. We established that the out‐of‐eclipse variability of the most targets gradually changes from small‐amplitude two‐waved type to big‐amplitude one‐waved type and vice versa, i.e. their spot activity cycles pass through phase of two almost diametrically opposite spots and phase of big polar cool spot. We found that the low‐temperature targets show flare activity of UV Cet‐type with amplitudes of 0.002–0.22 mag and duration of up to several hours. (© 2016 WILEY‐VCH Verlag GmbH & Co. KGaA, Weinheim)
The dosimetric properties of phosphate glass systems prepared by different chemical nanomaterials
Authors: Abdelhalim Mohamed Anwar K. , Al‐Shamrani Bandar Mora
Published: June 2016

The synthesis and characterization of glass systems were carried out using prepared nanocrystals injected into a glass matrix as a thermoluminescence (TL) activator using the melt–quenching method. Sample 1 was prepared as [40P2O5 50BaO:2.5MgO, 2.5Na2O, 5TiO2], sample 2 as [37.5P2O5 37.5CaO:25TiO2] and sample 3 as [50P2O5–50Li2O]. Formation of the synthesized compound was confirmed by studying the X‐ray diffraction (XRD) patterns and scanning electron microscopy (SEM) images. An annealing procedure was carried out for 1 h at 400 °C. The glow curve position and shape shifted dramatically and linearly to the higher temperature values on increasing the heating rate. A heating rate of 30 °C/s was the most suitable for obtaining a high TL response. Samples 2 and 3 have the highest TL response, which approached the effective atomic number (Zeff) of natural bone. The observed TL sensitivity of the prepared samples 2 and 3 is less than that of commercially available ‘TLD‐200 chips’ and LiF:Mg,Ti (TLD‐100) phosphor. Sample [37.5P2O5 37.5CaO:25TiO2] would be useful in personal and environmental dosimetry for measuring high doses of gamma radiation. Sample [50P2O5–50Li2O] is a good dosimeter, although it requires the addition of an appropriate transitional metal (activator) to overcome the problem of high fading. Copyright © 2016 John Wiley & Sons, Ltd.
Meta-analysis of the current prevalence of screen-detected abdominal aortic aneurysm in women
Authors: Ulug P , Powell J T , Sweeting M J , Bown M J , Thompson S G , Thompson S G , Sweeting M J , Jones E , Powell J T , Ulug P , Bown M J , Glover M J
Published: June 2016

Background

Although women represent an increasing proportion of those presenting with abdominal aortic aneurysm (AAA) rupture, the current prevalence of AAA in women is unknown. The contemporary population prevalence of screen-detected AAA in women was investigated by both age and smoking status.

Methods

A systematic review was undertaken of studies screening for AAA, including over 1000 women, aged at least 60 years, done since the year 2000. Studies were identified by searching MEDLINE, Embase and CENTRAL databases until 13 January 2016. Study quality was assessed using the Newcastle–Ottawa scoring system.

Results

Eight studies were identified, including only three based on population registers. The largest studies were based on self-purchase of screening. Altogether 1 537 633 women were screened. Overall AAA prevalence rates were very heterogeneous, ranging from 0·37 to 1·53 per cent: pooled prevalence 0·74 (95 per cent c.i. 0·53 to 1·03) per cent. The pooled prevalence increased with both age (more than 1 per cent for women aged over 70 years) and smoking (more than 1 per cent for ever smokers and over 2 per cent in current smokers).

Conclusion

The current population prevalence of screen-detected AAA in older women is subject to wide demographic variation. However, in ever smokers and those over 70 years of age, the prevalence is over 1 per cent.
Conjugated Dienyl Derivatives by Green Bisallylic Substitution: Synthetic and Mechanistic Insight
Authors: Cazorla Clément , Billamboz Muriel , Chevrin‐Villette Carole , Hapiot Frédéric , Monflier Eric , Len Christophe
Published: June 2016

The first palladium‐catalyzed bisallylic substitution on biobased bisallylic derivatives was explored. The developed method, performed under green conditions with microwave irradiation, led to valuable conjugated dienes. The mechanism was studied by ESI‐MS and NMR spectroscopy, which highlighted the involvement of bis‐π‐allylpalladium complexes in the catalytic cycle.
Simulation of Radiant Syngas Coolers and Comparison with Various Arrangements of the Entrained‐Flow Gasifier
Authors: Li Xianbin , Gong Yan , Zhou Zhijie , Dai Zhenghua , Yu Guangsuo
Published: June 2016

A 3D numerical model was developed for studying the multiphase flow and heat transfer process in a radiant syngas cooler (RSC). Realizable k‐ϵ turbulent and discrete random walk models were adopted to simulate gas phase and particle phase flow fields, respectively. The surface temperature of the membrane wall was calculated by heat flux balance equations. The calculated temperature distribution was validated by comparing calculated values with measured data of an industrial RSC. Four different membrane wall arrangements of RSC, namely, ordinary membrane wall (OMW), partial division wall (PDW), annular division wall (ADW), and fin division wall (FDW), were designed for a specific condition.
SnFe2O4 Nanocrystals as Highly Efficient Catalysts for Hydrogen‐Peroxide Sensing
Authors: Lee Kuan‐Ting , Liu Dai‐Ming , Lu Shih‐Yuan
Published: June 2016

SnFe2O4 nanocrystals (NC), prepared with a simple one‐step carrier‐solvent‐assisted interfacial reaction process, were developed as highly efficient catalysts for hydrogen peroxide sensing. These NCs, with a size of around 7 nm, served as the sensing catalyst and were decorated onto the pore surfaces of a porous fluorine‐doped tin oxide (PFTO) host electrode, prepared from commercial FTO glass with a simple anodic treatment, to form the sensing electrode for hydrogen peroxide. The SnFe2O4 NCs‐loaded PFTO electrode exhibited an ultra‐high sensitivity of 1027 mA m−1 cm−2 toward hydrogen peroxide, outperforming Pt NCs‐loaded PFTO electrodes. The SnFe2O4 NCs‐loaded PFTO electrode proved a promising relatively low cost, high performance sensing electrode for hydrogen peroxide.
Cooperative Veratryle and Nitroindoline Cages for Two‐Photon Uncaging in the NIR
Authors: Cueto Diaz Eduardo , Picard Sébastien , Klausen Maxime , Hugues Vincent , Pagano Paolo , Genin Emilie , Blanchard‐Desce Mireille
Published: June 2016

Tandem uncaging systems in which a two‐photon absorbing module and a cage moiety, linked via a phosphorous clip, that act together by Förster resonance energy transfer (FRET) have been developed. A library of these compounds, using different linkers and cages (7‐nitroindolinyl or nitroveratryl) has been synthesized. The investigation of their uncaging and two‐photon absorption properties demonstrates the scope and versatility of the engineering strategy towards efficient two‐photon cages and reveals surprising cooperative and topological effects. The interactions between the 2PA module and the caging moiety are found to promote cooperative effects on the 2PA response while additional processes that enhance the uncaging efficiency are operative in well‐oriented nitroindoline‐derived dyads. These synergic effects combine to lead to record two‐photon uncaging cross‐section values (i.e., up to 20 GM) for uncaging of carboxylic acids.
Temperature Dual Enantioselective Control in a Rhodium‐Catalyzed Michael‐Type Friedel–Crafts Reaction: A Mechanistic Explanation
Authors: Méndez Isabel , Rodríguez Ricardo , Polo Víctor , Passarelli Vincenzo , Lahoz Fernando J. , García‐Orduña Pilar , Carmona Daniel
Published: June 2016

By changing the temperature from 283 to 233 K, the S (99 % ee) or R (96 % ee) enantiomer of the Friedel–Crafts (FC) adduct of the reaction between N‐methyl‐2‐methylindole and trans‐β‐nitrostyrene can be obtained by using (SRh,RC)‐[(η5‐C5Me5)Rh{(R)‐Prophos}(H2O)][SbF6]2 as the catalyst precursor. This catalytic system presents two other uncommon features: 1) The ee changes with reaction time showing trends that depend on the reaction temperature and 2) an increase in the catalyst loading results in a decrease in the ee of the S enantiomer. Detection and characterization of the intermediate metal–nitroalkene and metal–aci‐nitro complexes, the free aci‐nitro compound, and the FC adduct‐complex, together with solution NMR measurements, theoretical calculations, and kinetic studies have allowed us to propose two plausible alternative catalytic cycles. On the basis of these cycles, all the above‐mentioned observations can be rationalized. In particular, the reversibility of one of the cycles together with the kinetic resolution of the intermediate aci‐nitro complexes account for the high ee values achieved in both antipodes. On the other hand, the results of kinetic measurements explain the unusual effect of the increment in catalyst loading.
Synthesis and Electrochemical Behavior of Electron‐Rich s‐Tetrazine and Triazolo‐tetrazine Nitrate Esters
Authors: Myers Thomas W. , Snyder Christopher J. , Chavez David E. , Scharff R Jason , Veauthier Jacqueline M.
Published: June 2016

We have prepared energetic nitrate ester derivatives of 1,2,4,5‐tetrazine and 1,2,4‐triazolo[4,3‐b]‐[1,2,4,5]‐tetrazine ring systems as model compounds to study the electrochemical behavior of tetrazines in the presence of explosive groups. The model compounds showed lower thermal stabilities relative to PETN (pentaerythritol tetranitrate), but slightly improved mechanical sensitivities. The presence of electron‐rich amine donors leads to a cathodic shift of the tetrazine redox potentials relative to those of previously reported tetrazine explosives. At these potentials, electron‐rich tetrazines with either covalently bound or co‐dissolved nitrate ester groups are irreversibly reduced. Effectively, changes in the electronic structure of tetrazines affect their electrochemical response to the presence of nitrate ester groups. Thus, it may be possible to develop tetrazine‐based electrochemical sensors for the detection of specific explosives and electrocatalysts for their disposal.
Unprecedented {Fe14}/{Fe10} Polyoxotungstate‐Based Nanoclusters with Efficient Photocatalytic H2 Evolution Activity: Synthesis, Structure, Magnetism, and Electrochemistry
Authors: Singh Vikram , Chen Zhiyuan , Ma Pengtao , Zhang Dongdi , Drew Michael G. B. , Niu Jingyang , Wang Jingping
Published: June 2016

Novel Fe10 and Fe14 clusters [Rb9Cs4H37Fe10O34(A‐α‐PW9O31)3(OH)3]⋅36 H2O (1) and [H3Rb3Fe14(OH)12(PO4)6(B‐α‐PW9O34)2]⋅21 H2O (2) were synthesized and characterized in the solid state by single‐crystal X‐ray diffraction, IR spectroscopy, thermogravimetric analysis (TGA), and magnetic studies, and in solution by electrochemistry. Cluster 1 is a decameric FeIII polyanionic cluster encapsulating a cesium atom in the center. Cluster 2 is a unique tetradecanuclear FeIII sandwich structure with phosphate‐linked units featuring two quasicubic Fe4O4 moieties. Apparently, 2 has the highest nuclearity of all known FeIII sandwich‐type polyoxometalate clusters. Clusters 1 and 2 also act as photocatalysts with platinum as cocatalyst for H2 evolution from light‐driven water splitting. Changes in the cyclovoltammetric patterns with variations in pH were observed for 1 and 2, most likely due to intermolecular interactions among the high‐nuclearity FeIII cluster cores and subsequent changes in the acid–base properties of the two reduced POMs. Magnetic studies provide evidence of antiferromagnetic interactions in 1 and 2. TGA showed that complexes 1 and 2 decompose between 580 and 590 °C.
Formal Total Synthesis of Diazonamide A by Indole Oxidative Rearrangement
Authors: David Nadège , Pasceri Raffaele , Kitson Russell R. A. , Pradal Alexandre , Moody Christopher J.
Published: June 2016

A short formal total synthesis of the marine natural product diazonamide A is described. The route is based on indole oxidative rearrangement, and a number of options were investigated involving migration of tyrosine or oxazole fragments upon oxidation of open chain or macrocyclic precursors. The final route proceeds from 7‐bromoindole by sequential palladium‐catalysed couplings of an oxazole fragment at C‐2, followed by a tyrosine fragment at C‐3. With the key 2,3‐disubstituted indole readily in hand, formation of a macrocyclic lactam set the stage for the crucial oxidative rearrangement to a 3,3‐disubstituted oxindole. Notwithstanding the concomitant formation of the unwanted indoxyl isomer, the synthesis successfully delivered, after deprotection, the key oxindole intermediate, thereby completing a formal total synthesis of diazonamide A.