bluuebunny/crossref_metadata_2025 huggingface dataset:
Concerning the helium‐to‐hydrogen number density ratio in very slow ejecta and winds near solar minimum
Authors: Vasquez Bernard J. , Farrugia C. J. , Simunac K. D. C. , Galvin A. B. , Berdichevsky D. B.
Published: January 2017

Near the solar minimum the average value of the helium‐to‐proton number density ratio is a strong function of speed. The average ratios for both solar ejecta and ambient winds obey approximately the same relation with speed. At the lowest speeds, the ratio takes on small values near and below 0.01. Here winds and ejecta with very slow speeds (310 km/s) are examined. STEREO and Wind spacecraft data are employed that were obtained from 2007 to 2010. This was during the prolonged solar activity minimum between cycles 23 and 24. Case event and statistical studies are made with 12 very slow ejecta. The helium‐to‐proton ratio in very slow ejecta relative to the ratio for very slow winds of comparable speed averaged in an inclusive 1 year period is 1.06. The ejecta and ambient slow winds have, then, nearly the same concentrations on average. The values did not approach 0 with decreasing speed and are shown to deviate from a predicted form. A survey of potential solar sources of very slow ejecta and other inferences based on interplanetary data found a strong correspondence with active regions and a dependence of the properties of very slow ejecta with the solar cycle.
Brown and Korringa constants for heterogeneous thinly layered poroelastic media
Authors: Wollner Uri , Mavko Gary
Published: January 2017

Macromechanical characterization of a layered poroelastic package treated as a homogeneous (upscaled) medium is presented. The characterization is based on the knowledge of the poroelastic properties of the package's constituents. Specifically, we provide closed‐form expressions for the sum of the fourth‐order average elastic compliances tensor
of the solid frame and pore space compressibility 1/Kϕ, previously defined in Brown and Korringa's extended formulation of the Gassmann's fluid substitution equations. These constants allow, thus, to perform fluid substitution on an upscaled composite consisting of poroelastic layers. Each layer within the layered package is assumed to have isotropic symmetry, uniform porosity, and single pore‐filling fluid and composed of several homogeneously distributed mineral phases such that each layer is approximately Gassmann consistent; however, the fluid and mineral phases as well as the porosity may vary from one layer to the next along the package. In addition, we obtain insights into the sensitivity of
and 1/Kϕ when an approximate fluid substitution operation is used. Moreover, it is shown that the
of the upscaled medium can have transverse isotropy symmetry. The degree of anisotropy is controlled by the volume fractions of individual layers and the contrast of elastic properties between the layers. The results for
and 1/Kϕ are compared to those obtained by Berryman and Milton (BM) for a two‐phase isotropic composite. At a limiting case of an effectively isotropic medium, this paper's results coincide with those of BM.
Seasonality of the mass concentration and chemical composition of aerosols around an urbanized basin in East Asia
Authors: Chou C. C.‐K. , Hsu W.‐C. , Chang S.‐Y. , Chen W.‐N. , Chen M.‐J. , Huang W.‐R. , Huang S.‐H. , Tsai C.‐Y. , Chang S.‐C. , Lee C.‐T. , Liu S.‐C.
Published: January 2017

This study investigated seasonal variations in the mass concentration and chemical composition of ambient aerosols observed at three stations (coastal, mountainous, and downtown sites) in northern Taiwan from March 2009 to February 2012. The results show that the major aerosol components include ammonium, sulfate, nitrate, sea salt, dust, organic carbon, and elemental carbon, whereas the mass fraction of each species depends on the sampling location and season. A significant correlation (r = 0.7–0.8) was observed in aerosol concentrations measured at the respective stations, indicating that aerosol concentrations were dominated by regional‐scale factors. Ammonium, sulfate, and nitrate consistently reached respective peak values in the spring in conjunction with dust particle levels. This shows that the transport of dust and particulate air pollutants from the Asian continent has affected the atmospheric environment in this area. Distinct seasonality was observed for sea salt and secondary organic carbon (SOC): sea salt levels peaked in the autumn, whereas SOC levels peaked in the summer, implying that their sources were regulated by independent seasonal factors. Correlation between sea salt concentration and surface wind speed was derived from coastal measurements and showed a high value for the wind speed sensitivity parameter of around 0.37 for our location. In addition, it was revealed that the SOC concentration in aerosols was positively correlated with oxidant photolysis index (Ox × UVB), suggesting that the SOC seasonality was dominated by hydroxyl radical production.
Generation of real‐time mode high‐resolution water vapor fields from GPS observations
Authors: Yu Chen , Penna Nigel T. , Li Zhenhong
Published: January 2017

Pointwise GPS measurements of tropospheric zenith total delay can be interpolated to provide high‐resolution water vapor maps which may be used for correcting synthetic aperture radar images, for numeral weather prediction, and for correcting Network Real‐time Kinematic GPS observations. Several previous studies have addressed the importance of the elevation dependency of water vapor, but it is often a challenge to separate elevation‐dependent tropospheric delays from turbulent components. In this paper, we present an iterative tropospheric decomposition interpolation model that decouples the elevation and turbulent tropospheric delay components. For a 150 km × 150 km California study region, we estimate real‐time mode zenith total delays at 41 GPS stations over 1 year by using the precise point positioning technique and demonstrate that the decoupled interpolation model generates improved high‐resolution tropospheric delay maps compared with previous tropospheric turbulence‐ and elevation‐dependent models. Cross validation of the GPS zenith total delays yields an RMS error of 4.6 mm with the decoupled interpolation model, compared with 8.4 mm with the previous model. On converting the GPS zenith wet delays to precipitable water vapor and interpolating to 1 km grid cells across the region, validations with the Moderate Resolution Imaging Spectroradiometer near‐IR water vapor product show 1.7 mm RMS differences by using the decoupled model, compared with 2.0 mm for the previous interpolation model. Such results are obtained without differencing the tropospheric delays or water vapor estimates in time or space, while the errors are similar over flat and mountainous terrains, as well as for both inland and coastal areas.
Quantifying the causes of differences in tropospheric OH within global models
Authors: Nicely Julie M. , Salawitch Ross J. , Canty Timothy , Anderson Daniel C. , Arnold Steve R. , Chipperfield Martyn P. , Emmons Louisa K. , Flemming Johannes , Huijnen Vincent , Kinnison Douglas E. , Lamarque Jean‐François , Mao Jingqiu , Monks Sarah A. , Steenrod Stephen D. , Tilmes Simone , Turquety Solene
Published: January 2017

The hydroxyl radical (OH) is the primary daytime oxidant in the troposphere and provides the main loss mechanism for many pollutants and greenhouse gases, including methane (CH4). Global mean tropospheric OH differs by as much as 80% among various global models, for reasons that are not well understood. We use neural networks (NNs), trained using archived output from eight chemical transport models (CTMs) that participated in the Polar Study using Aircraft, Remote Sensing, Surface Measurements and Models, of Climate, Chemistry, Aerosols and Transport Model Intercomparison Project (POLMIP), to quantify the factors responsible for differences in tropospheric OH and resulting CH4 lifetime (τCH4) between these models. Annual average τCH4, for loss by OH only, ranges from 8.0 to 11.6 years for the eight POLMIP CTMs. The factors driving these differences were quantified by inputting 3‐D chemical fields from one CTM into the trained NN of another CTM. Across all CTMs, the largest mean differences in τCH4 (ΔτCH4) result from variations in chemical mechanisms (ΔτCH4 = 0.46 years), the photolysis frequency (J) of O3 → O(1D) (0.31 years), local O3 (0.30 years), and CO (0.23 years). The ΔτCH4 due to CTM differences in NOx (NO + NO2) is relatively low (0.17 years), although large regional variation in OH between the CTMs is attributed to NOx. Differences in isoprene and J(NO2) have negligible overall effect on globally averaged tropospheric OH, although the extent of OH variations due to each factor depends on the model being examined. This study demonstrates that NNs can serve as a useful tool for quantifying why tropospheric OH varies between global models, provided that essential chemical fields are archived.
2,3‐Pentandion [MAK Value Documentation in German language, 2017]
Authors: Hartwig Andrea ,   MAK‐Kommission
Published: January 2017

2,3‐Pentanedione [pentane‐2,3‐dione]

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated 2,3‐pentanedione to derive a maximum concentration at the workplace (MAK value), considering all toxicity endpoints. The critical effects of 2,3‐pentanedione were inflammation, necrosis, ulceration and fibrosis in the lung and inflammation, exudates and metaplasia in the nasal cavity in rats and mice after inhalation for 14 days. In this study the NOAEC in rats was 49 ml/m3and the LOAEC in mice was 49 ml/m3for effects in the lung. The occurrence of fibrosis after only two weeks of inhalation is assessed as a severe effect. Due to the structural similarity of 2,3‐pentanedione to diacetyl (2,3‐butanedione), which is responsible for bronchiolitis obliterans in popcorn workers, and the likeliness of lung effects in rodents, a MAK value of 0.02 ml/m3is set in analogy to diacetyl. As the critical effect is systemic, 2,3‐pentanedione is assigned to Peak Limitation Category II. The excursion factor of 1 is set in analogy to diacetyl. Skin contact may contribute significantly to systemic toxicity and 2,3‐pentanedione is designated with an “H”. In analogy to diacetyl, skin sensitization (Sh) is expected but not airway sensitization. Because there are no studies on developmental toxicity, the substance is assigned to Pregnancy Risk Group D. 2,3‐Pentanedione is neither genotoxic nor carcinogenic.
N,N‐Dimethylformamid [MAK Value Documentation in German language, 2017]
Authors: Hartwig Andrea ,   MAK‐Kommission
Published: January 2017

N,N‐Dimethylformamide

The German Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area has evaluated the possibility to add the indication "prerequisite for Pregnancy Risk Group C” to the classification of Pregnancy Risk Group B for dimethylformamide at the maximum concentration at the workplace (MAK value) of 5 ml/m
3
. The NOAECs for developmental toxicity are 31 ml/m
3
in rats and 50 ml/m
3
in rabbits. Only a LOAEL is available for mice. From this LOAEL of 182 mg/kg body weight/day, which after toxicokinetic scaling corresponds to a concentration of 67 ml/m
3
at the workplace, the Commission estimated a NAEC of 22 ml/m
3
.

After whole body exposure of volunteers to dimethylformamide, the same amount was found to be taken up from the gas phase via the lung as via the skin. Therefore, damage to the embryo or foetus is unlikely at the concentration of 1 ml/m
3
and less. An exposure not higher than this concentration would be the prerequisite for an assignment to Pregnancy Risk Group C.
Electrochemistry of Organoaluminum Compounds
Authors: Shterenberg Ivgeni , Salama Michael , Gofer Yosef , Aurbach Doron
Published: January 2017

In this chapter, selected and the most important aspects of the electrochemistry of organoaluminum compounds are described. It is focused on two main implementations: electrochemical aluminum plating and rechargeable Mg batteries. Electrochemical aspects of organoaluminum‐based electroplating baths are discussed in detail and the effects of the solutions formulation on the electrochemical properties are explained. The role of organoaluminum compounds, acting as Lewis acids, in the formulation of the electrolyte solutions for rechargeable Mg batteries, and their effect on the performance of electrolyte solutions is described.
The Elephant in the Road: Auditory Perceptual Load Affects Driver Perception and Awareness
Authors: Murphy Gillian , Greene Ciara M.
Published: January 2017

Summary

Perceptual load theory research has shown that the level of perceptual load in a task affects processing of additional information. Less certain are the cross‐modal effects of perceptual load—does load in one modality affect processing in another? The current study assessed the effect of auditory perceptual load on visual attention in a driving simulator task. While driving, participants listened to traffic updates on the radio, which imposed either low or high perceptual load. Awareness for an unexpected animal as well as less novel objects (such as billboards and other vehicles) was markedly reduced under high load. Driver behaviour was also significantly affected, with impaired lateral control, longer reaction times to hazards and more collisions under high load. This study has important implications for load theory and also more general implications for road safety, as it suggests that auditory load may be an important, often overlooked factor in driver attention.Copyright © 2017 John Wiley & Sons, Ltd.
Novel combination schemes of individual weighting factors sign subband adaptive filter algorithm
Authors: Yu Yi , Zhao Haiquan
Published: January 2017

To improve the performance of the recently presented individual weighting factors sign subband adaptive filter (IWF‐SSAF) algorithm, its 2 combination algorithms using different step sizes are proposed. The first algorithm is to convexly combine the weight vectors of a large step‐size IWF‐SSAF filter and a small step‐size one; and the second algorithm is to obtain a time‐varying step size for the IWF‐SSAF by combining a large step size and a small one. The minimization of the sum of the l1‐norm of subband errors is used to indirectly update the mixing parameters in these 2 algorithms through a modified sigmoidal function. Moreover, in the first algorithm, to implement a smooth transition from the large step‐size IWF‐SSAF filter to the small step‐size one, the component filters receive a cyclic feedback of the combined weight vector. Both proposed algorithms have almost the same convergence performance, but the second algorithm saves computational cost. Simulation results in impulsive noise scenarios demonstrate the superiority of our proposed algorithms.
Late‐Stage Diversification of Non‐Steroidal Anti‐Inflammatory Drugs by Transition Metal‐Catalyzed C–H Alkenylations, Thiolations and Selenylations
Authors: Ma Wenbo , Dong Hongbo , Wang Daoxin , Ackermann Lutz
Published: January 2017

Ruthenium‐ and silver‐catalyzed selective C–H alkenylations, thiolations and selenylations of phenazone (antipyrine) – a non‐steroidal anti‐inflammatory drug – have been developed. This method features ample substrate scope, affording typically the mono‐ortho alkenylated, thiolated and selenylated products in good yields with complete site selectivity control. This strategy offers an efficient protocol for the modification of antipyrine derivatives.

magnified image
The α‐Thioglycoligase Derived from a GH89 α‐N‐Acetylglucosaminidase Synthesises α‐N‐Acetylglucosamine‐Based Glycosides of Biomedical Interest
Authors: Tshililo Ndivhuwo Olga , Strazzulli Andrea , Cobucci‐Ponzano Beatrice , Maurelli Luisa , Iacono Roberta , Bedini Emiliano , Corsaro Maria Michela , Strauss Erick , Moracci Marco
Published: January 2017

We report here on the preparation of a novel α‐thioglycoligase that can be used for the fast and efficient synthesis of α‐N‐acetylglucosamine‐based glycosides. Using the α‐N‐acetyl‐glucosaminidase from Clostridium perfringens of family GH89 (according to the Carbohydrate Active Enzymes classification) as starting point, we prepared mutants in the acid/base residue glutamic acid 483 that were found to have different synthetic efficiencies (maximal yields >80% after 24 h) in the presence of an activated donor and suitable acceptors. The synthetic potential of the Glu483 alanine mutant as an α‐thioglycoligase – only the third biocatalyst with this stereospecificity reported to date, and the first selective for the N‐acetylglucosamine moiety – was demonstrated by producing for the first time N‐acetyl‐α‐d‐glucosaminyl azide and N‐acetylglucosamine α‐thioglycosides in high yields. To showcase the application of such compounds, we show that they offer the wild‐type CpGH89 protection from thermal unfolding, demonstrating their potential as pharmacological chaperones for the treatment of mucopolysaccharidosis IIIB (Sanfilippo syndrome).

magnified image
Ruthenium‐Catalyzed Aminomethylation and Methylation of Phenol Derivatives Utilizing Methanol as the C1 Source
Authors: Kim Seoksun , Hong Soon Hyeok
Published: January 2017

A reaction involving ortho‐aminomethylation of phenol was developed via ruthenium‐catalyzed dehydrogenation of methanol, an environmentally benign C1 building block, without the use of reactive reagents. The reaction was successfully applied to a range of substrates. When naphthol was employed instead of phenol, only methylation was observed. On the basis of various mechanistic studies, we propose that formamide barely participates in the reaction, which mainly occurs through an iminium cation intermediate. The difference in the reactivities of phenol and naphthol is attributable to stronger basicity of naphtholate as a conjugate base owing to its lower aromaticity. Plausible reaction pathways were proposed for both reactions.

magnified image
Sandwiched liquid metal membrane (SLiMM) for hydrogen purification
Authors: Yen Pei‐Shan , Deveau Nicholas D. , Datta Ravindra
Published: January 2017

Significance

Palladium‐based membranes are currently the most advanced membranes for hydrogen separation and are on the verge of practical application. However, the search for alternative membranes continues in an effort to lower their cost and susceptibility to poisons. Here for the first time we report a novel sandwiched liquid metal membrane (SLiMM) for hydrogen separation. Permeation experiments indicate that the Ga/SiC SLiMM has a permeability ofat 500°C, which is 35 time higher than that for Pd under similar conditions. This promises a potential for application of SliMM in hydrogen purification. © 2016 American Institute of Chemical EngineersAIChE J, 63: 1483–1488, 2017
A Hexasaccharide Containing Rare 2‐O‐Sulfate‐Glucuronic Acid Residues Selectively Activates Heparin Cofactor II
Authors: Sankaranarayanan Nehru Viji , Strebel Tamara R. , Boothello Rio S. , Sheerin Kevin , Raghuraman Arjun , Sallas Florence , Mosier Philip D. , Watermeyer Nicholas D. , Oscarson Stefan , Desai Umesh R.
Published: January 2017

Glycosaminoglycan (GAG) sequences that selectively target heparin cofactor II (HCII), a key serpin present in human plasma, remain unknown. Using a computational strategy on a library of 46 656 heparan sulfate hexasaccharides we identified a rare sequence consisting of consecutive glucuronic acid 2‐O‐sulfate residues as selectively targeting HCII. This and four other unique hexasaccharides were chemically synthesized. The designed sequence was found to activate HCII ca. 250‐fold, while leaving aside antithrombin, a closely related serpin, essentially unactivated. This group of rare designed hexasaccharides will help understand HCII function. More importantly, our results show for the first time that rigorous use of computational techniques can lead to discovery of unique GAG sequences that can selectively target GAG‐binding protein(s), which may lead to chemical biology or drug discovery tools.
Reductive Homocoupling of Organohalides Using Nickel(II) Chloride and Samarium Metal
Authors: Liu Yongjun , Xiao Shuhuan , Qi Yan , Du Feng
Published: January 2017

A homocoupling method for organohalides and organosulfonates promoted by samarium metal and HMPA, and catalyzed by NiCl2 has been developed. Various organohalides (benzyl, aryl, heterocyclic, alkenyl and alkyl halides), α‐haloacetophenones, and phenyl organosulfonates were tolerated, and the reaction afforded coupling products with high efficiency. Excellent chemoselectivity was exhibited between halides and other groups, such as −COOH, −NO2, halogen, heterocyclic ring, ester, and ketone groups. The stereoselectivity suggested that the reaction mechanism might involve an organosamarium species.
DNA interaction with DAPI fluorescent dye: Force spectroscopy decouples two different binding modes
Authors: Reis L. A. , Rocha M. S.
Published: January 2017

In this work, we use force spectroscopy to investigate the interaction between the DAPI fluorescent dye and the λ‐DNA molecule under high (174 mM) and low (34 mM) ionic strengths. Firstly, we have measured the changes on the mechanical properties (persistence and contour lengths) of the DNA‐DAPI complexes as a function of the dye concentration in the sample. Then, we use recently developed models in order to connect the behavior of both mechanical properties to the physical chemistry of the interaction. Such analysis has allowed us to identify and to decouple two main binding modes, determining the relevant physicochemical (binding) parameters for each of these modes: minor groove binding, which saturates at very low DAPI concentrations (
 0.50 μM) and presents equilibrium binding constants of the order of ∼107 M−1 for the two ionic strengths studied; and intercalation, which starts to play a significant role only after the saturation of the first mode, presenting much smaller equilibrium binding constants (∼105 M−1).
One‐Pot Synthesis of Polyhydroquinoline Derivatives through Organic‐Solid‐Acid‐Catalyzed Hantzsch Condensation Reaction
Authors: Mondal Sujan , Patra Bidhan Chandra , Bhaumik Asim
Published: January 2017

We report the synthesis of a new porous polymeric network (PPN) using triphenylamine and α,α‐dibromo‐p‐xylene by a Friedel–Crafts alkylation promoted by anhydrous FeCl3 as an oxidizing agent. Sulfonation of PPN led to a sulfonated porous polymeric network (SPPN) having high surface acidity and high BET surface area. We characterized the PPN and SPPN materials thoroughly by using powder XRD, FTIR spectroscopy, 13C solid‐state magic‐angle spinning NMR, field‐emission SEM, high‐resolution TEM, and N2 sorption techniques. The sulfonated material SPPN was then employed as a heterogeneous, reusable, and environmentally benign organic solid‐acid catalyst for the one‐pot synthesis of biologically important polyhydroquinoline derivatives under microwave irradiation.
Bistability in Organic Magnetic Materials: A Comparative Study of the Key Differences between Hysteretic and Non‐hysteretic Spin Transitions in Dithiazolyl Radicals
Authors: Vela Sergi , Reardon Michael B. , Jakobsche Charles E. , Turnbull Mark M. , Ribas‐Arino Jordi , Novoa Juan J.
Published: January 2017

Dithiazolyl (DTA)‐based radicals have furnished many examples of organic spin‐transition materials, some of them occurring with hysteresis and some others without. Herein, we present a combined computational and experimental study aimed at deciphering the factors controlling the existence or absence of hysteresis by comparing the phase transitions of 4‐cyanobenzo‐1,3,2‐dithiazolyl and 1,3,5‐trithia‐2,4,6‐triazapentalenyl radicals, which are prototypical examples of non‐bistable and bistable spin transitions, respectively. Both materials present low‐temperature diamagnetic and high‐temperature paramagnetic structures, characterized by dimerized (⋅⋅⋅A−A⋅⋅⋅A−A⋅⋅⋅)n and regular (⋅⋅⋅A⋅⋅⋅A⋅⋅⋅A⋅⋅⋅A⋅⋅⋅)n π‐stacks of radicals, respectively. We show that the regular π‐stacks are not potential energy minima but average structures arising from a dynamic inter‐conversion between two degenerate dimerized configurations: (⋅⋅⋅A−A⋅⋅⋅A−A⋅⋅⋅)n↔(‐A⋅⋅⋅A−A⋅⋅⋅A‐)n. The emergence of this intra‐stack dynamics upon heating gives rise to a second‐order phase transition that is responsible for the change in the dominant magnetic interactions of the system. This suggests that the promotion of a (⋅⋅⋅A−A⋅⋅⋅A−A⋅⋅⋅)n↔(‐A⋅⋅⋅A−A⋅⋅⋅A‐)n dynamics is a general mechanism for triggering spin transitions in DTA‐based materials. Yet, this intra‐stack dynamics does not suffice to generate bistability, which also requires a rearrangement of the intermolecular bonds between the π‐stacks via a first‐order phase transition.
Modellexperimente im Chemieunterricht.
Authors: Sommer Katrin , Toschka Christina , Schröder Laura , Schröder Thomas Philipp , Steff Henning , Fischer Roland A.
Published: January 2017

Was sind Modellexperimente? Modellexperimente spielen im Chemieunterricht eine wichtige Rolle. Sie werden immer dann eingesetzt, wenn Experimente, die originale Sachverhalte widerspiegeln, aus Gründen der Komplexität, der Zugänglichkeit, des Gefahrenpotentials, der Handhabung und/oder der Kosten nicht zugänglich sind. In der chemiedidaktischen Literatur sowie in Chemie‐Schulbüchern besteht jedoch eine große Unschärfe bei dem Gebrauch dieses Begriffes. Für die Auseinandersetzung mit diesem Themenfeld ist es sowohl für die chemiedidaktische Forschung als auch für den Chemieunterricht wichtig, den Begriff Modellexperiment zu definieren, um u. a. bestehende Modellexperimente kritisch zu prüfen. Im vorliegenden Beitrag wird der Begriff Modellexperiment erstmalig für den Chemieunterricht Kriterien geleitet definiert. Diese Definition soll eine bewusste Abgrenzung der Modellexperimente von Simulationsmodellen, Denkmodellen und Funktionsmodellen etc. ermöglichen. Darauf aufbauend kann sich bei Experimenten, welche diese Kriterien eines Modellexperimentes aufweisen, die Quantität der modellierten Merkmale unterscheiden. Das wird im Modellierungsgrad ausgedrückt. Er erlaubt präzisere Aussagen über die Beziehung zwischen Modell und Original.
Large eddy simulations for blood dynamics in realistic stenotic carotids
Authors: Lancellotti Rocco Michele , Vergara Christian , Valdettaro Lorenzo , Bose Sanjeeb , Quarteroni Alfio
Published: January 2017

In this paper, we consider large eddy simulations (LES) for human stenotic carotids in presence of atheromasic plaque, a pathological condition where transitional effects to turbulence may occur, with relevant clinical implications such as plaque rupture. We provide a reference numerical solution obtained at high resolution without any subgrid scale model, to be used to assess the accuracy of LES simulations. In the context we are considering, ie, hemodynamics, we cannot refer to a statistically homogeneous, isotropic, and stationary turbulent regime; hence, the classical Kolmogorov theory cannot be used. For this reason, a mesh size and a time step are deemed fine enough if they allow to capture all the features of the velocity field in the shear layers developed after the bifurcation. To assess these requirements, we consider a simplified model of the evolution of a 2D shear layer, a relevant process in the formation of transitional effects in our case. Then, we compare the results of LES σ model (both static and dynamic) and mixed LES models (where also a similarity contribution is considered). In particular, we consider a realistic scenario of a human carotid, and we use the reference solution as gold standard. The results highlight the accuracy of the LES σ models, especially for the static model.
Nu@ge: A container‐based cloud computing service federation
Authors: Balouek‐Thomert Daniel , Caron Eddy , Gallard Pascal , Lefèvre Laurent
Published: January 2017

The adoption of cloud computing is still limited by several legal concerns that customers may have, such as data sovereignty. In cloud computing, data can be physically hosted in sensible locations, resulting in a lack of control for companies. In this context, we present the Nu@ge project, which aims at building a federation of container‐sized datacenters in the French territory. Nu@ge provides a software stack that enables companies to interconnect independent datacenters in a national mesh. A software architecture is presented and implemented as a federation of small datacenters deployed in France. The proposed architecture enables cooperation between local customized‐cloud managers and a federation‐wide middleware. It uses monitoring information from facilities and performance indicators from physical servers for managing the system, preventing incidents and considering energy efficiency. Additionally, a prototype of a container‐sized datacenter has been validated and patented.
Performance‐influence models of multigrid methods: A case study on triangular grids
Authors: Grebhahn Alexander , Rodrigo Carmen , Siegmund Norbert , Gaspar Francisco J. , Apel Sven
Published: January 2017

Multigrid methods are among the most efficient algorithms for solving discretized partial differential equations. Typically, a multigrid system offers various configuration options to tune performance for different applications and hardware platforms. However, knowing the best performing configuration in advance is difficult, because measuring all multigrid system variants is costly. Instead of direct measurements, we use machine learning to predict the performance of the variants. Selecting a representative set of configurations for learning is nontrivial, although, but key to prediction accuracy. We investigate different sampling strategies to determine the tradeoff between accuracy and measurement effort. In a nutshell, we learn a performance‐influence model that captures the influences of configuration options and their interactions on the time to perform a multigrid iteration and relate this to existing domain knowledge. In an experiment on a multigrid system working on triangular grids, we found that combining pair‐wise sampling with the D‐Optimal experimental design for selecting a learning set yields the most accurate predictions. After measuring less than 1 % of all variants, we were able to predict the performance of all variants with an accuracy of 95.9 %. Furthermore, we were able to verify almost all knowledge on the performance behavior of multigrid methods provided by 2 experts.
Defining the optimal dose of rifapentine for pulmonary tuberculosis: Exposure–response relations from two phase II clinical trials
Authors: Savic RM , Weiner M , MacKenzie WR , Engle M , Whitworth WC , Johnson JL , Nsubuga P , Nahid P , Nguyen NV , Peloquin CA , Dooley KE , Dorman SE ,   for the Tuberculosis Trials Consortium of the Centers for Disease Control and Prevention
Published: January 2017

Rifapentine is a highly active antituberculosis antibiotic with treatment‐shortening potential; however, exposure–response relations and the dose needed for maximal bactericidal activity have not been established. We used pharmacokinetic/pharmacodynamic data from 657 adults with pulmonary tuberculosis participating in treatment trials to compare rifapentine (n = 405) with rifampin (n = 252) as part of intensive‐phase therapy. Population pharmacokinetic/pharmacodynamic analyses were performed with nonlinear mixed‐effects modeling. Time to stable culture conversion of sputum to negative was determined in cultures obtained over 4 months of therapy. Rifapentine exposures were lower in participants who were coinfected with human immunodeficiency virus, black, male, or fasting when taking drug. Rifapentine exposure, large lung cavity size, and geographic region were independently associated with time to culture conversion in liquid media. Maximal treatment efficacy is likely achieved with rifapentine at 1,200 mg daily. Patients with large lung cavities appear less responsive to treatment, even at high rifapentine doses.
Islands within an island: Population genetic structure of the endemic Sardinian newt,Euproctus platycephalus
Authors: Ball Sarah E. , Bovero Stefano , Sotgiu Giuseppe , Tessa Giulia , Angelini Claudio , Bielby Jon , Durrant Christopher , Favelli Marco , Gazzaniga Enrico , Garner Trenton W. J.
Published: January 2017

The identification of historic and contemporary barriers to dispersal is central to the conservation of endangered amphibians, but may be hindered by their complex life history and elusive nature. The complementary information generated by mitochondrial (mtDNA) and microsatellite markers generates a valuable tool in elucidating population structure and the impact of habitat fragmentation. We applied this approach to the study of an endangered montane newt,Euproctus platycephalus. Endemic to the Mediterranean island of Sardinia, it is threatened by anthropogenic activity, disease, and climate change. We have demonstrated a clear hierarchy of structure across genetically divergent and spatially distinct subpopulations. Divergence between three main mountain regions dominated genetic partitioning with both markers. Mitochondrial phylogeography revealed a deep division dating to ca. 1 million years ago (Mya), isolating the northern region, and further differentiation between the central and southern regions ca. 0.5 Mya, suggesting an association with Pleistocene severe glacial oscillations. Our findings are consistent with a model of southward range expansion during glacial periods, with postglacial range retraction to montane habitat and subsequent genetic isolation. Microsatellite markers revealed further strong population structure, demonstrating significant divergence within the central region, and partial differentiation within the south. The northern population showed reduced genetic diversity. Discordance between mitochondrial and microsatellite markers at this scale indicated a further complexity of population structure, in keeping with male‐biased dispersal and female philopatry. Our study underscores the need to elucidate cryptic population structure in the ecology and conservation strategies for endangered island‐restricted amphibians, especially in the context of disease and climate change.
Antiperovskite Nitridophosphate Oxide Ho3[PN4]O by High‐Pressure Metathesis
Authors: Kloß Simon D. , Weidmann Niels , Schnick Wolfgang
Published: January 2017

Rare‐earth nitridophosphates are a recently discovered class of materials, which are accessible by high‐pressure metathesis. Antiperovskite‐type Ho3[PN4]O was synthesized from HoF3, LiPN2, Li3N, and Li2O at 5 GPa and ca. 1025 °C by this method and the multianvil technique. Ho3[PN4]O contains rarely observed isolated PN4 tetrahedra and can be derived by the hierarchical substitution of the ABX3 perovskite, in which Ho occupies the X positions, O occupies the B position, and the PN4 tetrahedra occupy the A position. The structure was refined on the basis of powder diffraction data [I4/mcm, a = 6.36112(3), c = 10.5571(1) Å, Z = 4, Rwp = 0.04, RBragg = 0.01, χ2 = 2.275] starting from the structural model of isotypic Gd3[SiN3O]O. To characterize Ho3[PN4]O, elemental analyses were performed through energy‐dispersive X‐ray spectroscopy (EDX) and inductively coupled plasma optical emission spectroscopy (ICP‐OES). Ho3[PN4]O is paramagnetic down to low temperatures with µeff = 10.43(1) µB and a Curie temperature (Θ) of 0.11(4) K. It shows the optical characteristics of Ho3+ ions and vibrations corresponding to isolated PN4 tetrahedra. On the basis of DFT calculations [generalized gradient approximation (GGA)], Ho3[PN4]O has an indirect band gap of 1.87 eV. We demonstrate the versatility of high‐pressure metathesis by attaining the low end of the P/N atomic ratio κ = 1/4. This confirms the previous assumption that rare‐earth nitridophosphates with κ = 1/2 to 1/4 are feasible by this method.
The importance of time‐varying volatility and country interactions in forecasting economic activity
Authors: Trypsteen Steven
Published: January 2017

This paper examines the relative importance of allowing for time‐varying volatility and country interactions in a forecast model of economic activity. Allowing for these issues is done by augmenting autoregressive models of growth with cross‐country weighted averages of growth and the generalized autoregressive conditional heteroskedasticity framework. The forecasts are evaluated using statistical criteria through point and density forecasts, and an economic criterion based on forecasting recessions. The results show that, compared to an autoregressive model, both components improve forecast ability in terms of point and density forecasts, especially one‐period‐ahead forecasts, but that the forecast ability is not stable over time. The random walk model, however, still dominates in terms of forecasting recessions.
Methylated free‐circulating HPP1 DNA is an early response marker in patients with metastatic colorectal cancer
Authors: Herbst Andreas , Vdovin Nikolay , Gacesa Sanja , Philipp Alexander , Nagel Dorothea , Holdt Lesca M. , op den Winkel Mark , Heinemann Volker , Stieber Petra , Graeven Ullrich , Reinacher‐Schick Anke , Arnold Dirk , Ricard Ingrid , Mansmann Ulrich , Hegewisch‐Becker Susanna , Kolligs Frank T
Published: January 2017

Detection of methylated free‐circulating DNA (mfcDNA) for hyperplastic polyposis 1 (HPP1) in blood is correlated with a poor prognosis for patients with metastatic colorectal cancers (mCRC). Here, we analyzed the plasma levels of HPP1 mfcDNA in mCRC patients treated with a combination therapy containing a fluoropyrimidine, oxaliplatin and bevacizumab to test whether HPP1 mfcDNA is a suitable prognostic and response biomarker. From 467 patients of the prospective clinical study AIO‐KRK‐0207, mfcDNA was isolated from plasma samples at different time points and bisulfite‐treated mfcDNA was quantified using methylation specific PCR. About 337 of 467 patients had detectable levels for HPP1 mfcDNA before start of treatment. The detection was significantly correlated with poorer overall survival (OS) (HR = 1.86; 95%CI 1.37–2.53). About 2–3 weeks after the first administration of combination chemotherapy, HPP1 mfcDNA was reduced to non‐detectable levels in 167 of 337 patients. These patients showed a better OS compared with patients with continued detection of HPP1 mfcDNA (HR HPP1(sample 1: pos/ sample 2: neg) vs. HPP1(neg/neg) = 1.41; 95%CI 1.00–2.01, HPP1(neg,pos/pos) vs. HPP1(neg/neg) = 2.60; 95%CI 1.86–3.64). Receiver operating characteristic analysis demonstrated that HPP1 mfcDNA discriminates well between patients who do (not) respond to therapy according to the radiological staging after 12 or 24 weeks (AUC = 0.77 or 0.71, respectively). Detection of HPP1 mfcDNA can be used as a prognostic marker and an early marker for response (as early as 3–4 weeks after start of treatment compared with radiological staging after 12 or 24 weeks) to identify patients who will likely benefit from a combination chemotherapy with bevacizumab.
Magnitude processing and complex calculation is negatively impacted by mathematics anxiety while retrieval‐based simple calculation is not
Authors: Lee Kyungmin , Cho Soohyun
Published: January 2017

Mathematics anxiety (MA) refers to the experience of negative affect when engaging in mathematical activity. According to Ashcraft and Kirk (2001), MA selectively affects calculation with high working memory (WM) demand. On the other hand, Maloney, Ansari, and Fugelsang (2011) claim that MA affects all mathematical activities, including even the most basic ones such as magnitude comparison. The two theories make opposing predictions on the negative effect of MA on magnitude processing and simple calculation that make minimal demands on WM. We propose that MA has a selective impact on mathematical problem solving that likely involves processing of magnitude representations. Based on our hypothesis, MA will impinge upon magnitude processing even though it makes minimal demand on WM, but will spare retrieval‐based, simple calculation, because it does not require magnitude processing. Our hypothesis can reconcile opposing predictions on the negative effect of MA on magnitude processing and simple calculation. In the present study, we observed a negative relationship between MA and performance on magnitude comparison and calculation with high but not low WM demand. These results demonstrate that MA has an impact on a wide range of mathematical performance, which depends on one's sense of magnitude, but spares over‐practiced, retrieval‐based calculation.
Evaluation of kodecytes using function‐spacer‐lipid constructs as a survey material for external proficiency testing for ABO subgrouping
Authors: Lim Young Ae , Kang Seon Joo
Published: January 2017

Background

It is not easy to find natural red blood cells (RBCs) with weak A (Aw) or weak B phenotype (Bw) for use as quality controls in ABO subgroup testing (subgrouping). The aim of this study was to prepare RBC kodecytes with synthetic blood group A and/or B function‐spacer‐lipid (FSL) constructs and to evaluate the possibility of using such kodecytes as a survey material for an external proficiency test (PT) to improve the quality of subgroup analysis.

Methods

Three types of survey samples, including O phenotype RBCs and A kodecytes with Aw (0.02 mg/mL FSL‐A solution) and B kodecytes with Bw (0.15 mg/mL FSL‐B solution) were sent to 53 laboratories for an educational trial of PT for subgrouping. Cell typing was done using the manual tube technique.

Results

Forty‐three laboratories responded, and the re‐activities of the survey samples varied from 0 to 4+ against anti‐A and anti‐B monoclonal reagents(MoAbs). Twenty‐nine laboratories (67%) correctly grouped the Bw kodecytes as Bw. Fifteen (35%), 21 (48%), and 6 (13%) laboratories grouped the Aw kodecytes as Aw, A2, and O phenotypes, respectively. The anti‐A MoAb clone affects the results of cell typing for Aw kodecytes. The stability of kodecytes was similar to that of natural O RBCs during storage.

Conclusion

Our kodecytes were useful as a survey material, and the survey results showed the necessity of materials for PT for subgrouping to improve the quality of laboratory analysis regardless of the different reactions according to the MoAb.
The total cholesterol to high‐density lipoprotein cholesterol as a predictor of poor outcomes in a Chinese population with acute ischaemic stroke
Authors: Chen Lifang , Xu Jianing , Sun Hao , Wu Hao , Zhang Jinsong
Published: January 2017

Background

High admission cholesterol has been associated with better outcome after acute ischaemic stroke (AIS), but a paradox not completely illustrated. The purpose of this study was to investigate the effect of the total cholesterol to high‐density lipoprotein cholesterol (TC/HDL‐C) on short‐term survival after AIS.

Methods

Consecutive patients admitted in 2013 and 2015 were enrolled in the present study. The logistic regression analysis was conducted to evaluate predictors of 3‐month outcomes. The primary endpoint was death. Secondary endpoint was good (modified Rankin Scale score 0‐2 or equal to prestrike modified Rankin Scale score) at 3 months.

Results

Of 871 patients enrolled in the final analysis, 94 (10.8%) individuals died during 3 months of observation. The serum TC and TC/HDL‐C levels at admission were significantly associated with stroke outcomes at 3 months, and the HDL‐C level was only correlated with the good outcomes at 3 months. Mortality risk was markedly decreased for patients with high TC/HDL‐C ratio (odds ratio: 0.23, 95% confidence interval [CI]: 0.10‐0.50 for Q4:Q1; P‐trend <.001) after adjustment. The effect of TC/HDL‐C ratio on the probability of good outcomes was still obvious (odds ratio: 2.18, 95% CI: 1.40‐3.39 for Q4:Q1; P‐trend=.029). According to the receiver operating characteristic analyses, the best discriminating factor was a TG/HDL‐C ≥3.37 (area under the ROC curve [AUC]=0.643, sensitivity 61.3%, specificity 61.7%) as well as the TC/HDL‐C ≥4.09 for good outcomes (AUC: 0.587, sensitivity 63.9%, specificity 79.7%).

Conclusions

High TC/HDL‐C ratio may be associated with increased short‐term survival and better outcomes after AIS.
STEM and HRTEM studies of accumulated deposits on human tooth surface
Authors: Wakasa Masanobu , Eshita Yoshiyuki , Nakanishi Kuniyuki , Isobe Tsutomu , Manago Kenji , Okamoto Masayuki , Isshiki Toshiyuki
Published: January 2017

The aim of this study was to clarify the fine structure of accumulated deposits on the surface of teeth that are considered to affect the gloss of teeth.

The study was carried out using, as specimens, human incisor teeth having gloss, which were extracted from teenage donors and those incapable of showing gloss even by brushing which were extracted from donors in their 50s. Thin longitudinal sections of tooth enamel with accumulated deposits on the surface were prepared by focused ion beam (FIB) milling, and the fine structure was analyzed using a scanning transmission electron microscope (STEM) and a high resolution transmission electron microscope (HRTEM).

By FIB, thin longitudinal sections could be prepared from tooth enamel together with organic and inorganic substances accumulated on the surface without artifacts. The accumulated deposits on the surface of teeth having gloss were composed of organic substances. However, it was first revealed by STEM observation that the accumulated solid deposits on the surface of teeth having no gloss had a complicated structure wherein inorganic and organic substances coexisted.

It is suggested that the organic substances contain proteins derived from saliva. The inorganic substances were spherical and needle‐like hydroxyapatites (HAs). It is considered that amino acids constituting the proteins affected the nucleus formation and the crystal formation of HA. It is considered that the unevenness of the accumulated deposits existing on the surface of tooth enamel having no gloss causes the decrease in gloss of teeth due to diffuse reflection of light.
Picture this: A field experiment of the influence of subtle affective stimuli on employee well‐being and performance
Authors: Hu Xiaoxiao , Zhan Yujie , Yao Xiang , Garden Rebecca
Published: January 2017

Prior literature examining the antecedents of employee affect has largely ignored subtle affective influences in the workplace and their impact on employees' affective experiences and behaviors. A substantial body of evidence from basic psychology research suggests that individuals' affect can be influenced by minimal stimulus input. The primary objective of this research is to take an initial step towards understanding the “real‐world” impact of subtle affective stimuli in the workplace. Specifically, in a field experiment with a within‐subjects design, we collected data from 68 sales representatives and examined the effect of a subtle affective stimulus (i.e., a black‐and‐white picture of a woman smiling printed on the backdrop of paper–pencil surveys) on employees' affect, well‐being, and performance. Results showed that the smiling picture significantly enhanced participants' positive affect, which in turn influenced employees' extra‐role performance and emotional exhaustion. The smiling picture also indirectly influenced employees' in‐role performance and emotional exhaustion via negative affect. Theoretical and practical implications of these findings are discussed at the end of the paper. Copyright © 2017 John Wiley & Sons, Ltd.