bluuebunny/crossref_metadata_2025 huggingface dataset:
Première mention de l’hélice des bois (Arianta arbustorum) au Québec et mention anecdotique du petit-gris (Cornu aspersum)
Authors: Picard Isabelle , Desroches Jean-François , Ethier Gilles
Published: November 2016

De nombreux individus de l’hélice des bois (Arianta arbustorum) ont été observés à Boucherville en juin 2015 et en 2016 ainsi qu’à l’Île-des-Soeurs en juin 2016. Cela représente les premières mentions de cette espèce au Québec et surtout, celles de populations viables. En 2015, un petit-gris (Cornu aspersum) juvénile a également été trouvé dans une grappe de raisins de Californie qui provenait d’une épicerie de Sherbrooke. Ces deux espèces d’escargots exotiques sont originaires d’Europe. Elles ont été introduites ailleurs au Canada et ne semblent pas envahissantes. Cependant, un suivi serait nécessaire pour vérifier la survie à plus long terme des populations d’hélice des bois à Boucherville et à l’Île-des-Soeurs et valider la présence de cette espèce ailleurs au Québec.
Extension de l’aire de répartition connue du campagnol sylvestre (Microtus pinetorum) : mention la plus nordique au Québec
Authors: Brouillette Patricia , Boulet Monique
Published: November 2016

Le campagnol sylvestre (Microtus pinetorum) occupe la partie est de l’Amérique du Nord. Au Canada, on le trouve dans le sud-ouest de l’Ontario et dans le sud-est du Québec. Compte tenu de sa répartition restreinte et fragmentée ainsi que de sa rareté relative, il a obtenu un statut d’espèce préoccupante au Canada en 1998. Il se caractérise notamment par le fait qu’il soit le seul campagnol fouisseur au pays. Le 28 août 2013, un spécimen a été capturé au lac Mondor à Saint-Jean-de-Matha, dans la région de Lanaudière, au Québec. Cette observation est la plus septentrionale à ce jour, et constitue la première et unique mention de l’espèce au nord du fleuve Saint-Laurent. Cet article propose un état de la situation de cette espèce au Québec et décrit le spécimen capturé ainsi que l’environnement où il a été trouvé afin de bonifier les connaissances scientifiques sur ce micromammifère peu commun.
Facteurs environnementaux associés à la prolifération de la méduse d’eau douce Craspedacusta sowerbii dans les lacs du Québec
Authors: El Moussaoui Nadia , Beisner Beatrix E.
Published: November 2016

Les proliférations (aussi appelées pullulations ou « blooms ») de la méduse d’eau douce Craspedacusta sowerbii semblent de plus en plus fréquentes dans les lacs d’Amérique du Nord. Cependant, puisqu’elles apparaissent sporadiquement, de façon discontinue dans le temps et l’espace, on connaît mal leur répartition, leur écologie et les facteurs environnementaux qui les influencent. Les objectifs du présent projet étaient de déterminer la répartition spatiale et les facteurs environnementaux responsables de la prolifération de C. sowerbii au Québec en vue de prévoir de nouvelles proliférations. À l’aide des données recueillies, nous avons cartographié la répartition des lacs québécois envahis par C. sowerbii jusqu’en 2014 et colligé des données sur les variables environnementales de ceux-ci : leur profondeur maximale, leur superficie, leur périmètre et leur altitude, ainsi que la transparence de l’eau et sa concentration en chlorophylle a, en carbone organique dissous (COD) et en phosphore total. En tout, l’espèce a été répertoriée dans 88 lacs au Québec, principalement dans les régions des Laurentides, de l’Outaouais et de l’Estrie, où les lacs sont particulièrement abondants. Selon nos analyses statistiques, les proliférations de cette méduse exotique au Québec ont été observées plus fréquemment dans les lacs dont la superficie est supérieure à 2,8 km² et dont l’eau a une concentration en phosphore total inférieure à 14,77 µg/l.
Évaluation de l’importance écologique de 9 étangs vernaux dans Gatineau, Québec
Authors: Piché Caroline , Bussières Nathalie , Soucie Josée
Published: November 2016

Nous avons évalué l’importance écologique de 9 étangs vernaux de Gatineau (Québec) en utilisant la méthode proposée par Calhoun et collab. (2005). L’un d’eux, situé au nord de la forêt Boucher, s’est démarqué par la richesse et l’abondance de sa faune amphibienne ainsi que par la présence de 4 espèces en situation précaire ou préoccupante. Cet étang atteint la valeur biologique maximale selon la grille d’évaluation utilisée. Nous formulons des recommandations de gestion dans un contexte d’urbanisation.
Mapping out Min protein patterns in fully confined fluidic chambers
Authors: Caspi Yaron , Dekker Cees
Published: November 2016

The bacterial Min protein system provides a major model system for studying reaction-diffusion processes in biology. Here we present the first in vitro study of the Min system in fully confined three-dimensional chambers that are lithography-defined, lipid-bilayer coated and isolated through pressure valves. We identify three typical dynamical behaviors that occur dependent on the geometrical chamber parameters: pole-to-pole oscillations, spiral rotations, and traveling waves. We establish the geometrical selection rules and show that, surprisingly, Min-protein spiral rotations govern the larger part of the geometrical phase diagram. Confinement as well as an elevated temperature reduce the characteristic wavelength of the Min patterns, although even for confined chambers with a bacterial-level viscosity, the patterns retain a ~5 times larger wavelength than in vivo. Our results provide an essential experimental base for modeling of intracellular Min gradients in bacterial cell division as well as, more generally, for understanding pattern formation in reaction-diffusion systems.
Connectivity map of bipolar cells and photoreceptors in the mouse retina
Authors: Behrens Christian , Schubert Timm , Haverkamp Silke , Euler Thomas , Berens Philipp
Published: November 2016

In the mouse retina, three different types of photoreceptors provide input to 14 bipolar cell (BC) types. Classically, most BC types are thought to contact all cones within their dendritic field; ON-BCs would contact cones exclusively via so-called invaginating synapses, while OFF-BCs would form basal synapses. By mining publically available electron microscopy data, we discovered interesting violations of these rules of outer retinal connectivity: ON-BC type X contacted only ~20% of the cones in its dendritic field and made mostly atypical non-invaginating contacts. Types 5T, 5O and 8 also contacted fewer cones than expected. In addition, we found that rod BCs received input from cones, providing anatomical evidence that rod and cone pathways are interconnected in both directions. This suggests that the organization of the outer plexiform layer is more complex than classically thought.
Relationship between sensitizer concentration and resist performance of chemically amplified extreme ultraviolet resists in sub-10 nm half-pitch resolution region
Authors: Kozawa Takahiro , Santillan Julius Joseph , Itani Toshiro
Published: November 2016

The development of lithography processes with sub-10 nm resolution is challenging. Stochastic phenomena such as line width roughness (LWR) are significant problems. In this study, the feasibility of sub-10 nm fabrication using chemically amplified extreme ultraviolet resists with photodecomposable quenchers was investigated from the viewpoint of the suppression of LWR. The relationship between sensitizer concentration (the sum of acid generator and photodecomposable quencher concentrations) and resist performance was clarified, using the simulation based on the sensitization and reaction mechanisms of chemically amplified resists. For the total sensitizer concentration of 0.5 nm−3 and the effective reaction radius for the deprotection of 0.1 nm, the reachable half-pitch while maintaining 10% critical dimension (CD) LWR was 11 nm. The reachable half-pitch was 7 nm for 20% CD LWR. The increase in the effective reaction radius is required to realize the sub-10 nm fabrication with 10% CD LWR.
Decomposition of Al2.7Fe0.3Ti in heated Al–Al2.7Fe0.3Ti refiner fabricated by spark plasma sintering and its refining performance
Authors: Watanabe Yoshimi , Hamada Takayuki , Sato Hisashi
Published: November 2016

In our previous study, a novel Al-L12-type Al2.7Fe0.3Ti refiner was fabricated by spark plasma sintering (SPS) and its refining performance was studied. It was found that L12-type Al2.7Fe0.3Ti particles can be favorable heterogeneous nucleation sites for Al casts, since the lattice matching between Al2.7Fe0.3Ti and Al is good. It was also found that the thermal stability of heterogeneous nucleation sites affects the grain-refining performance. In this study, the decomposition phenomena of the Al2.7Fe0.3Ti phase in a refiner are studied by heating an Al–Al2.7Fe0.3Ti refiner fabricated by SPS. In addition, the refining performance of a heated Al–Al2.7Fe0.3Ti refiner is investigated.
Modeled Martian subsurface elemental composition measurements with the Probing In situ with Neutron and Gamma ray instrument
Authors: Nowicki Suzanne F. , Evans Larry G. , Starr Richard D. , Schweitzer Jeffrey S. , Karunatillake Suniti , McClanahan Timothy P. , Moersch Jeffrey E. , Parsons Ann M. , Tate Christopher G.
Published: November 2016

The Probing In situ with Neutron and Gamma ray (PING) instrument is an innovative application of active neutron‐induced gamma ray technology. The objective of PING is to measure the elemental composition of the Martian regolith. This manuscript presents PING's sensitivities as a function of the Martian regolith depth and PING's uncertainties in the measurements as a function of observation time in passive and active mode. The modeled sensitivities show that in PING's active mode, where both a pulsed neutron generator (PNG) and a gamma ray spectrometer (GRS) are used, PING can interrogate the material below the rover to about 20 cm due to the penetrating nature of the high‐energy neutrons and the resulting secondary gamma rays observed with the GRS. PING is capable of identifying most major and minor rock‐forming elements, including H, O, Na, Mn, Mg, Al, Si, P, S, Cl, Cr, K, Ca, Ti, Fe, and Th. The modeled uncertainties show that PING's use of a PNG reduces the required observation times by an order of magnitude over a passive operating mode where the PNG is turned off. While the active mode allows for more complete elemental inventories with higher sensitivity, the gamma ray signatures of some elements are strong enough to detect in passive mode. We show that PING can detect changes in key marker elements and make thermal neutron measurements in about 1 min that are sensitive to H and Cl.
Inherited crustal deformation along the East Gondwana margin revealed by seismic anisotropy tomography
Authors: Pilia S. , Arroucau P. , Rawlinson N. , Reading A. M. , Cayley R. A.
Published: November 2016

The mechanisms of continental growth are a crucial part of plate tectonic theory, yet a clear understanding of the processes involved remains elusive. Here we determine seismic Rayleigh wave phase anisotropy variations in the crust beneath the southern Tasmanides of Australia, a Paleozoic accretionary margin. Our results reveal a complex, thick‐skinned pervasive deformation that was driven by the tectonic interaction between the proto‐Pacific Ocean and the ancient eastern margin of Gondwana. Stress‐induced effects triggered by the collision and entrainment of a microcontinent into the active subduction zone are evident in the anisotropy signature. The paleofracturing trend of failed rifting between Australia and Antarctica is also recorded in the anisotropy pattern as well as a tightly curved feature in central Tasmania. The observed patterns of anisotropy correlate well with recent geodynamic and kinematic models of the Tasmanides and provide a platform from which the spatial extent of deformational domains can be refined.
GDGT and alkenone flux in the northern Gulf of Mexico: Implications for the TEX86 and UK'37 paleothermometers
Authors: Richey Julie N. , Tierney Jessica E.
Published: November 2016

The TEX86 and
molecular biomarker proxies have been broadly applied in downcore marine sediments to reconstruct past sea surface temperature (SST). Although both TEX86 and
have been interpreted as proxies for mean annual SST throughout the global ocean, regional studies of glycerol dibiphytanyl glycerol tetraethers (GDGTs) and alkenones in sinking particles are required to understand the influence of seasonality, depth distribution, and diagenesis on downcore variability. We measure GDGT and alkenone flux, as well as the TEX86 and
indices in a 4 year sediment trap time series (2010–2014) in the northern Gulf of Mexico (nGoM), and compare these data with core‐top sediments at the same location. GDGT and alkenone fluxes do not show a consistent seasonal cycle; however, the largest flux peaks for both occurs in winter.
covaries with SST over the 4 year sampling interval, but the
‐SST relationship in this data set implies a smaller slope or nonlinearity at high temperatures when compared with existing calibrations. Furthermore, the flux‐weighted
value from sinking particles is significantly lower than that of underlying core‐top sediments, suggesting preferential diagenetic loss of the tri‐unsaturated alkenone in sediments. TEX86 does not covary with SST, suggesting production in the subsurface upper water column. The flux‐weighted mean TEX86 matches that of core‐top sediments, confirming that TEX86 in the nGoM reflects local planktonic production rather than allochthonous or in situ sedimentary production. We explore potential sources of uncertainty in both proxies in the nGoM but demonstrate that they show nearly identical trends in twentieth century SST, despite these factors.
A Bioinspired Ultraporous Nanofiber‐Hydrogel Mimic of the Cartilage Extracellular Matrix
Authors: Formica Florian A. , Öztürk Ece , Hess Samuel C. , Stark Wendelin J. , Maniura‐Weber Katharina , Rottmar Markus , Zenobi‐Wong Marcy
Published: November 2016

A true biomimetic of the cartilage extracellular matrix (ECM) could greatly contribute to our ability to regenerate this tissue in a mechanically demanding, often inflamed environment. Articular cartilage is a composite tissue made of cells and fibrillar proteins embedded in a hydrophilic polymeric meshwork. Here, a polyanionic functionalized alginate is used to mimic the glycosaminoglycan component of the native ECM. To create the fibrillar component, cryoelectrospinning of poly(ε‐caprolactone) on a −78 °C mandrel, subsequently treated by O2 plasma, is used to create a stable, ultraporous and hydrophillic nanofiber network. In this study, cell‐laden, fiber‐reinforced composite scaffolds thicker than 1.5 mm can be created by infiltrating a chondrocyte/alginate solution into the fiber mesh, which is then physically cross‐linked. The fibrillar component significantly reinforces the chondroinductive, but mechanically weak sulfated alginate hydrogels. This allows the production of a glycosaminoglycan‐ and collagen type II‐rich matrix by the chondrocytes as well as survival of the composite in vivo. To further enhance the system, the electrospun component is loaded with dexamethasone, which protected the cells from an IL‐1β‐mediated inflammatory insult.
Presence of an Immune System Increases Anti‐Tumor Effect of Ag Nanoparticle Treated Mice
Authors: Manshian Bella B. , Jimenez Julio , Himmelreich Uwe , Soenen Stefaan J.
Published: November 2016

To date, most nanomedical studies rely on the use of immune‐deficient mice in which the contribution of the immune system on the applied therapy is ignored. Here, the degradation of silver nanoparticles (Ag NPs) is exploited as a means to treat subcutaneous tumor models in mice. To investigate the impact of the immune system, the same tumor cell type (KLN 205 murine squamous cell carcinoma) is used in a xenograft model in NOD SCIDγ immune‐deficient mice and as a syngeneic model in immune‐competent DBA/2 mice. The Ag NPs are screened for their cytotoxicity on various cancer cell lines, indicating a concentration‐dependent induction of oxidative stress, mitochondrial damage, and autophagy on all cell types tested. At subcytotoxic concentrations, prolonged cellular exposure to the Ag NPs results in toxicity due to NP degradation and the generation of toxic Ag+ ions. At subcytotoxic conditions, the NPs are found to cause inflammation in vitro. Similar results are obtained in the immune‐competent mouse model, where clear inflammation is observed after treatment of the implanted tumors with Ag NPs. This inflammation leads to an ongoing antitumoral effect, which results in a significantly reduced tumor growth compared to Ag NP‐treated tumors in an immune‐deficient model.
Heterogeneous Monolithic Integration of Single‐Crystal Organic Materials
Authors: Park Kyung Sun , Baek Jangmi , Park Yoonkyung , Lee Lynn , Hyon Jinho , Koo Lee Yong‐Eun , Shrestha Nabeen K. , Kang Youngjong , Sung Myung Mo
Published: November 2016

Manufacturing high‐performance organic electronic circuits requires the effective heterogeneous integration of different nanoscale organic materials with uniform morphology and high crystallinity in a desired arrangement. In particular, the development of high‐performance organic electronic and optoelectronic devices relies on high‐quality single crystals that show optimal intrinsic charge‐transport properties and electrical performance. Moreover, the heterogeneous integration of organic materials on a single substrate in a monolithic way is highly demanded for the production of fundamental organic electronic components as well as complex integrated circuits. Many of the various methods that have been designed to pattern multiple heterogeneous organic materials on a substrate and the heterogeneous integration of organic single crystals with their crystal growth are described here. Critical issues that have been encountered in the development of high‐performance organic integrated electronics are also addressed.
Hybrid Plasmonic Cavity Modes in Arrays of Gold Nanotubes
Authors: Wang Junfeng , Zhang Cheng , Zhang Junxi , Song Haojie , Wang Pei , Lu Yonghua , Fei Guangtao , Xu Wen , Xu Wei , Zhang Lide , Kivshar Yuri S. , Zhang Lin
Published: November 2016

Plasmonic structures are known to confine light at the nanometer scale, and they exhibit enhanced electromagnetic fields localized in small mode volumes. Here, plasmonic resonators based on a metamaterial consisting of periodic arrays of gold nanotubes embedded into anodic aluminum oxide are studied and strong confinement of local fields with low losses is demonstrated. Higher‐order resonance modes of surface plasmons localized in gold nanotubes when the nanotube length exceeds some critical values are observed. The numerical simulations suggest that, the electric fields associated with some higher‐order longitudinal modes for the long nanotubes and some lower‐order longitudinal modes for the short nanotubes or the nanotubes with thin walls, are mainly localized at the interfaces between aluminum oxide and gold in the form of the standing‐wave longitudinal plasmonic modes, partially localized in the pores and at two ends of the nanotubes owing to the strong coupling of the Fabry–Pérot resonances with extraordinary optical transmission effect in the periodical structures through the inner nanochannels of the nanotubes, so that the nanotubes play a role of efficient cavity resonators. The existence of hybrid plasmonic resonant cavity modes with asymmetrical distributions of the electric field resulting from the near‐field coupling of both transversal and longitudinal modes in the gold nanotube metamaterials is revealed.
Chiral Aluminum Catalyst System for the Enantioselective Addition of Vinylaluminum Reagents to Aldehydes: Metal Controlled Reversal of Enantioselectivity
Authors: Adate Priyanka A. , Matsunaga Takuya , Shin Hirata , Harada Toshiro
Published: November 2016

A chiral aluminum catalyst system has been developed for the enantioselective vinylation of aldehydes. β,β‐Disubstituted (E)‐vinylaluminum reagents, generated regio‐ and stereoselectively by the carboalumination of terminal alkynes with trimethylalumunim (Me3Al), were used straightforwardly without transmetalation to vinyltitanium reagents in the subsequent enantioselective addition to aldehydes with a DPP‐H8‐BINOL‐derived chiral aluminum catalyst at low catalyst loading (5 mol%). The reaction afforded the corresponding enantiomerically enriched secondary allylic alcohols with a reversal of the selectivity observed in closely related reactions catalyzed by a chiral titanium complex derived from the same ligand.

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Iron‐Catalyzed Direct Alkylamination of Phenols with O‐Benzoyl‐N‐alkylhydroxylamines under Mild Conditions
Authors: Jia Lei , Gao Sen , Xie Junyao , Luo Meiming
Published: November 2016

A novel iron‐catalyzed direct alkylamination reaction of phenols has been achieved with O‐benzoyl‐N‐alkylhydroxylamines as aminating agents. This protocol provides a facile access to N‐alkyl‐substituted aminophenols though a radical reaction from phenols. The catalytic direct alkylamination operates at room temperature without the need of any ligands and additives to afford the desired products with excellent regioselectivity and functional group tolerance.

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Ligand‐Free Heck Reactions of Aryl Iodides: Significant Acceleration of the Rate through Visible Light Irradiation at Ambient Temperature
Authors: Zhang Heng , Huang Xueliang
Published: November 2016

A mild Heck reaction of aryl iodides and olefins was realized by the cooperation of a palladium and a photoredox catalyst under the irradiation of visible light. This protocol works well to synthesize stilbenes with high Z/E ratios and (E)‐cinnamates in the absence of ligands at ambient temperature. Control experiments revealed that palladium salt, visible light and photoredox catalyst were all crucial for the achievement of this cross‐coupling under mild conditions.

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Perfluoroalkanesulfonylation of Alkynyl(phenyl)iodonium Tosylates by the Weakly Nucleophilic Sodium Perfluoroalkanesulfinates
Authors: Han Jia‐Bin , Yang Lian , Chen Xing , Zha Gao‐Feng , Zhang Cheng‐Pan
Published: November 2016

An additive‐ and transition metal‐free perfluoroalkanesulfonylation of alkynyl(phenyl)iodonium tosylates with sodium perfluoroalkanesulfinates (RfnSO2Na) is described. The poorly nucleophilic RfnSO2Na reacted with alkynyl(phenyl)iodonium salts in dichloromethane at room temperature under a nitrogen atmosphere for 5–60 minutes to afford a variety of acetylenic triflones and alkynyl perfluoroalkyl sulfones in good to quantitative yields. The position of substituents on the phenyl rings of the arylethynyl moiety in the iodonium salts had a big influence on the reaction. The formation of five‐membered cyclic vinyl sulfones suggested that the reaction proceeds via an alkylidene carbene intermediate. Furthermore, successful scaling‐up of the reaction demonstrates the practicality of the new method. Advantages of the method include short reaction times, mild conditions, and the easy access to perfluoroalkanesulfonylation reagents (RfnSO2Na).

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Sulfination of Alcohols with p‐Toluenesulfonylmethyl Isocyanide under Metal‐Free Conditions: A Mitsunobu Approach
Authors: Kadari Lingaswamy , Radha Krishna Palakodety , Lakshmi Prapurna Y.
Published: November 2016

A Mitsunobu approach for the synthesis of sulfinate esters by direct nucleophilic substitution of alcohols is described. The salient features of this strategy include neutral and metal‐free conditions for the rapid synthesis of sulfinates in high yields. The present protocol using p‐toluenesulfonylmethyl isocyanide (TosMIC) and the triphenylphosphine (TPP)/diisopropyl azodicarboxylate (DIAD) reagent system represents the general synthetic route to this important class of compounds.

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Pore‐network modeling of particle retention in porous media
Authors: Yang Hongtao , Balhoff Matthew T.
Published: November 2016

Transport and filtration of micron and submicron particles in porous media is important in applications such as water purification, contaminants dispersion, and drilling mud invasion. Existing macroscopic models often fail to be predictive without empirical adjustments and a more fundamental approach may be required. We develop a physically‐representative, 3D pore network model based on a particle tracking method to simulate particle retention and permeability impairment in polydisperse particle systems. The model includes the effect of hydraulic drag, gravity, electrostatic and van der Waals forces, as well as Brownian motion. A converging‐diverging pore throat geometry is used to capture the mechanism of interception. With the analytical solution of fluid velocity within a pore throat, the trajectory of each particle is calculated explicitly. We also incorporate surface roughness and particle–surface interaction to determine particle attachment and detachment. Pore throat structure and conductivity are updated dynamically to account for the effect of deposited particles. Predictions of effluent concentration and macroscopic filtration coefficient are in good agreement with published experimental data. We find that the filtration coefficient is dependent on the relative angle between fluid flow and gravity. Particle deposition by interception is significant for large particle/grain size ratios. Brownian diffusion is the primary cause of retention at low Peclet numbers, especially for small gravity numbers. Particle size distribution is found to be a cause of hyperexponential deposition often observed in experiments. Permeability reduction was small for strong repulsive forces because particles only deposited in paths of slow velocity. © 2017 American Institute of Chemical EngineersAIChE J, 63: 3118–3131, 2017
Prediction and screening of solubility of pharmaceuticals in single‐ and mixed‐ionic liquids using COSMO‐SAC model
Authors: Lee Bong‐Seop , Lin Shiang‐Tai
Published: November 2016

In this work, we investigated the prediction of solubility (xd) of drug molecules in single‐ and mixed‐ionic liquid (IL) solutions using the COSMO‐SAC activity coefficient model. In particular, the effect of dissociation of IL on solubility is examined. The prediction accuracy is found to be 91% in xd (root‐mean‐square deviation in ln xd is 0.65) for a total of 442 data points with solubility ranging from 0.93 to 2.84 × 10−4 (mole fraction) and temperature ranging from 248.9 to 488.3 K. The solubility of drug is found not sensitive to the treatment of dissociation of IL in the calculations. The method is used to determine the solubility of paracetamol in 2624 single IL made from combination of 82 cations and 32 anions. The solubility of paracetamol can vary by 4 orders of magnitude in different ILs, indicating that this is a powerful method for screening for solvents with desired solubility power. The solubility of a drug in binary IL solution can be significantly higher or lower than those in pure IL components. For the 3,441,376 binary IL mixtures, about 8% of the mixtures exhibit higher solubility for paracetamol and 6% exhibit lower solubility. Our results indicate that mixing ILs can be a viable approach for tuning drug solubility. © 2017 American Institute of Chemical Engineers AIChE J, 63: 3096–3104, 2017
Die Molekülstruktur des pentagonal‐pyramidalen Hexamethylbenzol‐Dikations C6(CH3)62+ im Kristall
Authors: Malischewski Moritz , Seppelt K.
Published: November 2016

Gegenüber dem bekannten 2‐Norbornylkation, dessen Struktur bis zum kürzlich erfolgten kristallographischen Nachweis der Fünffach‐Koordination eines Kohlenstoffatoms lange umstritten war, hat das pentagonal‐pyramidale Hexamethylbenzol‐Dikation deutlich weniger Aufmerksamkeit erfahren. Es wurde zuerst 1973 bei tiefen Temperaturen in magischer Säure (HSO3F/SbF5) von Hogeveen erzeugt, der für die Verbindung auf Basis von NMR‐Spektroskopie und Reaktivitätsstudien eine nicht‐klassische Struktur mit sechsfach koordiniertem Kohlenstoff vorschlug. Die Isolierung und Bestimmung der Kristallstruktur gelangen jedoch nicht. C6(CH3)62+ wird bei der Reaktion von Hexamethyldewarbenzolepoxid mit HSO3F/SbF5 erhalten und kann durch einen Überschuss von wasserfreiem HF als SbF6−‐Salz auskristallisiert werden. Die Molekülstruktur von C6(CH3)62+(SbF6−)2⋅HSO3F belegt die pentagonal‐pyramidale Struktur des Dikations. Das apikale Kohlenstoffatom ist an eine Methylgruppe (Bindungslänge 1.479(3) Å) sowie an die fünf basalen Kohlenstoffatome gebunden (Bindungslängen 1.694(2)–1.715(3) Å).
Cyclic Amino(Ylide) Silylene: A Stable Heterocyclic Silylene with Strongly Electron‐Donating Character
Authors: Alvarado‐Beltran Isabel , Baceiredo Antoine , Saffon‐Merceron Nathalie , Branchadell Vicenç , Kato Tsuyoshi
Published: November 2016

An isolable heterocyclic silylene (4) with two different π‐donating substituents, namely a classical amino group and a more electropositive and stronger carbon‐based π‐donating phosphonium ylide, was synthesized and fully characterized. The combination of these two different π‐donating substituents confers high thermal stability and an unusual nucleophilic character on silylene 4. Therefore, silylene 4 behaves as a strong donor ligand toward transition metals with a donating character comparable to N‐heterocyclic carbenes, in contrast to classical N‐heterocyclic silylenes, which generally present a weak donating character.
Gram‐Scale Synthesis of Chiral Cyclopropane‐Containing Drugs and Drug Precursors with Engineered Myoglobin Catalysts Featuring Complementary Stereoselectivity
Authors: Bajaj Priyanka , Sreenilayam Gopeekrishnan , Tyagi Vikas , Fasan Rudi
Published: November 2016

Engineered hemoproteins have recently emerged as promising systems for promoting asymmetric cyclopropanations, but variants featuring predictable, complementary stereoselectivity in these reactions have remained elusive. In this study, a rationally driven strategy was implemented and applied to engineer myoglobin variants capable of providing access to 1‐carboxy‐2‐aryl‐cyclopropanes with high trans‐(1R,2R) selectivity and catalytic activity. The stereoselectivity of these cyclopropanation biocatalysts complements that of trans‐(1S,2S)‐selective variants developed here and previously. In combination with whole‐cell biotransformations, these stereocomplementary biocatalysts enabled the multigram synthesis of the chiral cyclopropane core of four drugs (Tranylcypromine, Tasimelteon, Ticagrelor, and a TRPV1 inhibitor) in high yield and with excellent diastereo‐ and enantioselectivity (98–99.9% de; 96–99.9% ee). These biocatalytic strategies outperform currently available methods to produce these drugs.
Crystal Structure Determination of the Pentagonal‐Pyramidal Hexamethylbenzene Dication C6(CH3)62+
Authors: Malischewski Moritz , Seppelt K.
Published: November 2016

In contrast to the well‐known 2‐norbornyl cation, the structure of which was a matter of long debate until its pentacoordinated nature was recently proven by an X‐ray structure, the pentagonal‐pyramidal dication of hexamethylbenzene has received considerably less attention. This species was first prepared by Hogeveen in 1973 at low temperatures in magic acid (HSO3F/SbF5), for which he proposed a non‐classical structure (containing a hexacoordinated carbon) based on NMR spectroscopy and reactivity studies, but no X‐ray crystal structure has been reported. C6(CH3)62+ can be obtained through the dissolution of hexamethyl Dewar benzene epoxide in HSO3F/SbF5 and crystallized as the SbF6− salt upon addition of excess anhydrous hydrogen fluoride. The crystal structure of C6(CH3)62+ (SbF6−)2⋅HSO3F confirms the pentagonal pyramidal structure of the dication. The apical carbon is bound to one methyl group (distance 1.479(3) Å) and to the five basal carbon atoms (distances 1.694(2)–1.715(3) Å).
Conversion of the Native 24‐mer Ferritin Nanocage into Its Non‐Native 16‐mer Analogue by Insertion of Extra Amino Acid Residues
Authors: Zhang Shengli , Zang Jiachen , Wang Wenming , Chen Hai , Zhang Xiaorong , Wang Fudi , Wang Hongfei , Zhao Guanghua
Published: November 2016

Protein assemblies with high symmetry are widely distributed in nature. Most efforts so far have focused on repurposing these protein assemblies, a strategy that is ultimately limited by the structures available. To overcome this limitation, methods for fabricating novel self‐assembling proteins have received intensive interest. Herein, by reengineering the key subunit interfaces of native 24‐mer protein cage with octahedral symmetry through amino acid residues insertion, we fabricated a 16‐mer lenticular nanocage whose structure is unique among all known protein cages. This newly non‐native protein can be used for encapsulation of bioactive compounds and exhibits high uptake efficiency by cancer cells. More importantly, the above strategy could be applied to other naturally occurring protein assemblies with high symmetry, leading to the generation of new proteins with unexplored functions.
S‐Benzylisothiourea complex of palladium on magnetic nanoparticles: A highly efficient and reusable nanocatalyst for synthesis of polyhydroquinolines and Suzuki reaction
Authors: Ghorbani‐Choghamarani Arash , Tahmasbi Bahman , Moradi Zahra
Published: November 2016

S‐Benzylisothiourea complex of palladium supported on modified Fe3O4 magnetic nanoparticles (Pd‐SBTU@Fe3O4) is reported for carbon–carbon coupling through the Suzuki coupling reaction. Also, the synthesis of polyhydroquinoline derivatives is reported in the presence of Pd‐SBTU@Fe3O4 as nanocatalyst. The prepared nanoparticles were characterized using Fourier transform infrared spectroscopy, thermogravimetric analysis, scanning electron microscopy, vibrating sample magnetometry and inductively coupled plasma atomic emission spectroscopy. The nanocatalyst was easily recovered using an external magnet and reused several times without significant loss of its catalytic efficiency. The heterogeneity of Pd‐SBTU@Fe3O4 was studied using hot filtration.
Investigation of catalytic properties of two new orthopalladated complexes supported on montmorillonite: Synthesis, characterization and application in aerobic oxidation of alcohols
Authors: Karami Kazem , Hashemi Sara , Dinari Mohammad
Published: November 2016

Two new complexes, [Pd(L1)(C,N)]NO3 (1) and [Pd(L2)(C,N)]NO3 (2) (L1 = 5‐nitro‐1,10‐phenanthroline, L2 = 4‐methyl‐1,10‐phenanthroline, C,N = benzylamine), have been synthesized and characterized using infrared and NMR spectroscopies and elemental analysis. Montmorillonite (MMT‐K10 clay) was used as a solid support for incorporating the cationic part of complexes 1 and 2 to produce catalysts 1 and 2, respectively, as heterogeneous catalysts. Catalyst 1 was identified using powder X‐ray diffraction and scanning and transmission electron microscopies, and the content of palladium obtained from inductively coupled plasma analysis. By changing the electron‐donating group on the L1 ligand with an electron‐withdrawing one, a minor improvement was observed in the catalytic properties. Catalyst 1 showed better efficiency for oxidation of benzyl alcohol in comparison with catalyst 2, so catalyst 1 was used for the aerobic oxidation of alcohols to corresponding aldehydes or ketones without over‐oxidation (with and without bubbling of air). This catalytic system showed high activity towards alcohols under mild conditions. Finally, the reusability of catalyst 1 was investigated with multiple reuses of the supported catalyst in subsequent alcohol oxidation reactions.
Blinded versus unblinded estimation of a correlation coefficient to inform interim design adaptations
Authors: Kunz Cornelia U. , Stallard Nigel , Parsons Nicholas , Todd Susan , Friede Tim
Published: November 2016

Regulatory authorities require that the sample size of a confirmatory trial is calculated prior to the start of the trial. However, the sample size quite often depends on parameters that might not be known in advance of the study. Misspecification of these parameters can lead to under‐ or overestimation of the sample size. Both situations are unfavourable as the first one decreases the power and the latter one leads to a waste of resources. Hence, designs have been suggested that allow a re‐assessment of the sample size in an ongoing trial. These methods usually focus on estimating the variance. However, for some methods the performance depends not only on the variance but also on the correlation between measurements. We develop and compare different methods for blinded estimation of the correlation coefficient that are less likely to introduce operational bias when the blinding is maintained. Their performance with respect to bias and standard error is compared to the unblinded estimator. We simulated two different settings: one assuming that all group means are the same and one assuming that different groups have different means. Simulation results show that the naïve (one‐sample) estimator is only slightly biased and has a standard error comparable to that of the unblinded estimator. However, if the group means differ, other estimators have better performance depending on the sample size per group and the number of groups.
Absolute Molecular Weight Determination of Sodium Salt of Methacrylic Acid/Acrylic Acid‐2‐Isooctyl Ester/2‐Acrylamido‐2‐Methylpropanesulfonic Acid Terpolymer by GPC/MALLS
Authors: Chang Xiaoping , Liu Zequan , Zhang Qiang
Published: November 2016

The samples of sodium salt of methacrylic acid/acrylic acid‐2‐isooctyl ester/2‐acrylamido‐2‐methylpropanesulfonic acid terpolymer (SSMAA) were synthesized by free radical solution polymerization. The absolute weight‐average molar mass (Mw
) and polydispersity (Mw
/Mn
) of the polymers were successfully determined using aqueous‐based gel permeation chromatography coupled with multiangle laser light scattering. The results show that mixed solutions of highly concentrated buffered salt (NaNO3
or NaCl and NaH2PO4
) and organic solvent modifier (methanol) are needed to eliminate the undesirable interactions between polymer and polymer, and between polymer and stationary phase. Dynamic light scattering was first used to investigate the aggregation behavior of SSMAA in a variety of potential mobile phase compositions and screen the optimum compositions. The Mw
and Mw
/Mn
values of the three samples prepared with different amount of initiator are 13500, 5820, and 2490 g/mol and 1.52, 1.45, and 1.47, respectively.
Sequential One‐Pot Synthesis of Imidazoles and 2H‐Imidazolones from β‐Ketoamines, Acylating Agents and Ammonium Acetate
Authors: Jalani Hitesh B. , Venkateswararao Eeda , Manickam Manoj , Jung Sang‐Hun
Published: November 2016

An efficient, practical, straight forward, and transition metal‐free three‐component synthesis of diversely substituted imidazoles and 2H‐imidazolones from β‐ketoamines, acylating agents, and ammonium acetate has been described herein. This approach involves [3+1+1] cyclization through consecutive formation of three C–N bonds as a sequence of initial amidation of β‐ketoamines with acylating agent, β‐iminoketoamide formation with ammonia, and acid catalyzed concomitant cyclodehydration to afford the imidazoles and 2H‐imidazolones. This methodology has advantages such as single flask operation, readily available starting materials, mild conditions, broad functional groups tolerance, and simple work‐up procedure.
Flipping the classroom to improve learning with MOOCs technology
Authors: Muñoz‐Merino Pedro J. , Ruipérez‐Valiente José A. , Delgado Kloos Carlos , Auger Maria A. , Briz Susana , de Castro Vanessa , Santalla Silvia N.
Published: November 2016

The use of Massive Open Online Courses (MOOCs) is increasing worldwide and brings a revolution in education. The application of MOOCs has technological but also pedagogical implications. MOOCs are usually driven by short video lessons, automatic correction exercises, and the technological platforms can implement gamification or learning analytics techniques. However, much more analysis is required about the success or failure of these initiatives in order to know if this new MOOCs paradigm is appropriate for different learning situations. This work aims at analyzing and reporting whether the introduction of MOOCs technology was good or not in a case study with the Khan Academy platform at our university with students in a remedial Physics course in engineering education. Results show that students improved their grades significantly when using MOOCs technology, student satisfaction was high regarding the experience and for most of the different provided features, and there were good levels of interaction with the platform (e.g., number of completed videos or proficient exercises), and also the activity distribution for the different topics and types of activities was appropriate. © 2016 Wiley Periodicals, Inc. Comput Appl Eng Educ 25:15–25, 2017; View this article online at wileyonlinelibrary.com/journal/cae; DOI 10.1002/cae.21774
Design of an Intermediate Fluid Vaporizer for Liquefied Natural Gas
Authors: Xu Shuangqing , Chen Xuedong , Fan Zhichao
Published: November 2016

The intermediate fluid vaporizer (IFV) owns various advantages over other types of liquefied natural gas (LNG) vaporizers. Research findings related to the design of an IFV, including configurational variations, selection of candidate working fluids, one‐dimensional steady‐state thermal model, computational fluid dynamics (CFD) model for thermal dynamic analysis, and cold energy recovery have been reviewed. Further updates to the current one‐dimensional thermal model are needed. A three‐dimensional unsteady CFD model should be established for the instantaneous flow and heat transfer analysis. Integrating the LNG regasification and cold energy recovery will bring more complexity in process design, optimization, and operation.
Impact of Energy Crop Rotation Design on Multiple Aspects of Resource Efficiency
Authors: Peter Christiane , Glemnitz Michael , Winter Katharina , Kornatz Peter , Müller Janine , Heiermann Monika , Aurbacher Joachim
Published: November 2016

Biogas production can cause environmental problems due to a biased alignment of one energy crop used as a feedstock, e.g., maize in Germany. Diversification of crop rotations and resource‐efficient management can be the key to sustainable crop management. Four crop rotations on eight sites across Germany were evaluated in terms of their resource efficiency (area use, energy, and economic efficiency) to derive options. Analysis revealed high variation in all indicators under review, with a high variance explanation by the interaction between crop rotation and regional characteristics. Furthermore, results indicate that high area‐specific methane yields do not equate to high energy efficiency. Crop management adaptation is a useful tool for optimizing resource efficiency.
Quick decisions tend to reinforce self‐interest choices among MBA students: The direct and moderating effects of temporal constraint and situational factors in ethical decision making
Authors: Andiappan Meena , Dufour Lucas
Published: November 2016

Employees face increasingly time‐pressured operational environments. Using theory from Reynolds' () neurocognitive model of ethical decision making, we explore how temporal constraint, consequence framing, and organizational norms affect self‐interested decision making in business. Conducting three experimental manipulations with a sample of MBA students, we found the following: First, consistent with previous studies, high time pressure promotes self‐interested intentions. Second, unethical framing encourages self‐interested intentions, though this relationship is unaffected by the presence of time pressure. Third, unethical organizational norms encourage group‐interested intentions. Lastly, however, when these same norms are experienced under high time pressure, individuals display self‐interested intentions. Copyright © 2016 ASAC. Published by John Wiley & Sons, Ltd.
SME internationalization research: Mapping the state of the art
Authors: Ribau Cláudia P. , Moreira António Carrizo , Raposo Mário
Published: November 2016

This paper offers a review of published conceptual and empirical studies indexed in the main academic search databases, covering literature on the internationalization of small and medium‐sized firms. We analyzed a total of 554 papers covering the period between 1977 and 2014, and found the following general trends: empirical research focuses mainly on Europe and is characterized by a diversity that identifies 74 different topics. This study provides academics and practitioners with a clear perspective on future directions of SME internationalization and contributes to our understanding of the relevant research to date. Copyright © 2016 ASAC. Published by John Wiley & Sons, Ltd.
Activity of Fluorine‐Containing Analogues of WC‐9 and Structurally Related Analogues against Two Intracellular Parasites: Trypanosoma cruzi and Toxoplasma gondii
Authors: Chao María N. , Li Catherine , Storey Melissa , Falcone Bruno N. , Szajnman Sergio H. , Bonesi Sergio M. , Docampo Roberto , Moreno Silvia N. J. , Rodriguez Juan B.
Published: November 2016

Two obligate intracellular parasites, Trypanosoma cruzi, the agent of Chagas disease, and Toxoplasma gondii, an agent of toxoplasmosis, upregulate the mevalonate pathway of their host cells upon infection, which suggests that this host pathway could be a potential drug target. In this work, a number of compounds structurally related to WC‐9 (4‐phenoxyphenoxyethyl thiocyanate), a known squalene synthase inhibitor, were designed, synthesized, and evaluated for their effect on T. cruzi and T. gondii growth in tissue culture cells. Two fluorine‐containing derivatives, the 3‐(3‐fluorophenoxy)‐ and 3‐(4‐fluorophenoxy)phenoxyethyl thiocyanates, exhibited half‐maximal effective concentration (EC50) values of 1.6 and 4.9 μm, respectively, against tachyzoites of T. gondii, whereas they showed similar potency to WC‐9 against intracellular T. cruzi (EC50 values of 5.4 and 5.7 μm, respectively). In addition, 2‐[3‐ (phenoxy)phenoxyethylthio]ethyl‐1,1‐bisphosphonate, which is a hybrid inhibitor containing 3‐phenoxyphenoxy and bisphosphonate groups, has activity against T. gondii proliferation at sub‐micromolar levels (EC50=0.7 μm), which suggests a combined inhibitory effect of the two functional groups.
Multiphase fluid‐solid coupled analysis of shock‐bubble‐stone interaction in shockwave lithotripsy
Authors: Wang Kevin G.
Published: November 2016

A novel multiphase fluid‐solid–coupled computational framework is applied to investigate the interaction of a kidney stone immersed in liquid with a lithotripsy shock wave (LSW) and a gas bubble near the stone. The main objective is to elucidate the effects of a bubble in the shock path to the elastic and fracture behaviors of the stone. The computational framework couples a finite volume 2‐phase computational fluid dynamics solver with a finite element computational solid dynamics solver. The surface of the stone is represented as a dynamic embedded boundary in the computational fluid dynamics solver. The evolution of the bubble surface is captured by solving the level set equation. The interface conditions at the surfaces of the stone and the bubble are enforced through the construction and solution of local fluid‐solid and 2‐fluid Riemann problems. This computational framework is first verified for 3 example problems including a 1D multimaterial Riemann problem, a 3D shock‐stone interaction problem, and a 3D shock‐bubble interaction problem. Next, a series of shock‐bubble‐stone–coupled simulations are presented. This study suggests that the dynamic response of a bubble to LSW varies dramatically depending on its initial size. Bubbles with an initial radius smaller than a threshold collapse within 1 μs after the passage of LSW, whereas larger bubbles do not. For a typical LSW generated by an electrohydraulic lithotripter (pmax = 35.0MPa, pmin =− 10.1MPa), this threshold is approximately 0.12mm. Moreover, this study suggests that a noncollapsing bubble imposes a negative effect on stone fracture as it shields part of the LSW from the stone. On the other hand, a collapsing bubble may promote fracture on the proximal surface of the stone, yet hinder fracture from stone interior.