bluuebunny/crossref_metadata_2025 huggingface dataset:
Quelle est la place de la créativité organisationnelle dans les PME en hypercroissance ?1
Authors: Chanut-Guieu Cécile , Guieu Gilles
Published: August 2014

La créativité, sous des formes diverses, s’avère être un facteur essentiel de développement et de performance des PME. Il paraît intéressant d’identifier les processus de créativité à l’oeuvre dans des contextes exacerbés. L’un de ces contextes est celui des PME en hypercroissance, dans lesquelles le rythme de développement invite l’entreprise à exploiter ses ressources dans une urgence permanente. Dans ces PME, en privilégiant une lecture organisationnelle de la créativité, deux questions centrales se posent : quelles sont les conditions favorables à la créativité dans les PME en hypercroissance ? La créativité suffit-elle à générer, puis à maintenir un niveau de croissance rapide ? Des données issues d’une dizaine d’études de cas, totalisant 48 entretiens sont mobilisées pour y répondre. Un travail de repérage dans ces entretiens des principaux termes liés à la créativité est effectué, complété par l’examen d’autres sources secondaires qui ont permis de connaître en profondeur les cas étudiés. Deux résultats centraux concernant la créativité dans les PME en hypercroissance sont proposés : (1) le dirigeant joue un rôle central pour organiser les conditions favorables à la créativité ; (2) la créativité est nécessaire, mais non suffisante. L’hypercroissance nécessite des processus de créativité jugulés par des processus de stabilisation/rationalisation. Nous proposons alors que l’hypercroissance est générée par la gestion paradoxale du couple créativité-routine.
L’identification collective d’opportunités
Authors: Tremblay Maripier
Published: August 2014

Pour plusieurs aspirants entrepreneurs, trouver une « bonne » opportunité est une étape difficile. Arriver à reconnaître une opportunité nécessite, au niveau individuel, un certain nombre de connaissances et d’informations, de même qu’une certaine dose de créativité. Pour pallier ces limites individuelles, une avenue intéressante est de mettre à contribution des groupes ou une collectivité pour identifier des opportunités, ce qui permet de multiplier les connaissances et favorise la créativité. C’est le pari qui a été fait dans certains milieux, en réunissant différents groupes d’acteurs dans des démarches structurées afin de reconnaître des opportunités dans leur environnement. Bien qu’intéressantes, ces démarches posent la question suivante : le processus de reconnaissance d’opportunités peut-il être abordé comme un processus collectif ? Pour Tremblay et Carrier (2006), il s’agit d’une avenue non seulement pertinente pour la pratique, mais justifiable d’un point de vue théorique. Ceci étant dit, on connaît peu les facteurs influençant un tel processus et permettant d’en assurer le succès. Afin de répondre à cette question, une étude exploratoire par théorisation enracinée a été réalisée à partir de cinq cas de démarches collectives. Au final, l’étude a permis d’illustrer le processus collectif de reconnaissance d’opportunités et certains facteurs permettant d’en maximiser les retombées. Les résultats permettent de confirmer les rapprochements entre identification d’opportunités et créativité et offrent des repères pour orienter l’action des intervenants et conséquemment, d’améliorer les retombées de telles pratiques.
Laboratory chamber measurements of the longwave extinction spectra and complex refractive indices of African and Asian mineral dusts
Authors: Di Biagio C. , Formenti P. , Styler S. A. , Pangui E. , Doussin J.‐F.
Published: August 2014

In this study we present the first results from laboratory chamber experiments newly designed to investigate the longwave optical properties of mineral dust. Extinction spectra in the 2–16 µm range have been measured in situ (T = 293 K, RH < 2%) for polydispersed pure dust aerosols generated from natural parent soils from Tunisia, Niger, and the Gobi desert. Data are used in combination with particle size distributions to estimate the complex refractive index of each dust sample. Our results show that the magnitude and spectral dependence of the dust extinction and refractive indices differ according to particle mineralogy, suggesting the necessity for regionally resolved optical properties for modeling dust radiative effects in the longwave. The magnitude of extinction is controlled by the particle size distribution and remains significant down to low coarse particle concentrations, indicating that the longwave effect of mineral dust persists throughout long‐range transport and is thus relevant at the global scale.
Ground‐based ELF/VLF chorus observations at subauroral latitudes—VLF‐CHAIN Campaign
Authors: Shiokawa Kazuo , Yokoyama Yu , Ieda Akimasa , Miyoshi Yoshizumi , Nomura Reiko , Lee Sungeun , Sunagawa Naoki , Miyashita Yukinaga , Ozaki Mitsunori , Ishizaka Kazumasa , Yagitani Satoshi , Kataoka Ryuho , Tsuchiya Fuminori , Schofield Ian , Connors Martin
Published: August 2014

We report observations of very low frequency (VLF) and extremely low frequency (ELF) chorus waves taken during the ELF/VLF Campaign observation with High‐resolution Aurora Imaging Network (VLF‐CHAIN) of 17–25 February 2012 at subauroral latitudes at Athabasca (L=4.3), Canada. ELF/VLF waves were measured continuously with a sampling rate of 100 kHz to monitor daily variations in ELF/VLF emissions and derive their detailed structures. We found quasiperiodic (QP) emissions whose repetition period changes rapidly within a period of 1 h without corresponding magnetic pulsations. QP emissions showed positive correlation between amplitude and frequency sweep rate, similarly to rising‐tone elements. We found an event of nearly simultaneous enhancements of QP emissions and Pc1/electromagnetic ion cyclotron wave intensities, suggesting that the temperature anisotropy of electrons and ions developed simultaneously at the equatorial plane of the magnetosphere. We also found QP emissions whose intensity suddenly increased in association with storm sudden commencement without changing their frequency. Falling‐tone ELF/VLF emissions were observed with their rate of frequency change varying from 0.7 to 0.05 kHz/s over 10 min. Bursty‐patch emissions in the lower and upper frequency bands are often observed during magnetically disturbed periods. Clear systematic correlation between these various ELF/VLF emissions and cosmic noise absorption was not obtained throughout the campaign period. These observations indicate several previously unknown features of ELF/VLF emissions in subauroral latitudes and demonstrate the importance of continuous measurements for monitoring temporal variations in these emissions.
Far‐field DOA estimation and near‐field localization for multipath signals
Authors: Elbir Ahmet M. , Tuncer T. Engin
Published: August 2014

In direction finding and localization applications, multipath signals are important sources of error for parameter estimation. When the antenna array receives multipath reflections which are coherent with the far‐field line‐of‐sight signal, estimating the far‐ and near‐field components becomes an important problem. In this paper, a new method is proposed to estimate the direction‐of‐arrival (DOA) of the far‐field source and to localize its near‐field multipaths. Far‐field source DOA is estimated using calibration of the antenna array. A near‐to‐far transformation is proposed for the estimation of the near‐field source DOA angles. In order to estimate the near‐field range parameters, a compressive sensing approach is presented where a dictionary with near‐field sources with different ranges is employed. As a result, the proposed method estimates the far‐field and near‐field source DOAs as well as the range and the signal amplitudes of the near‐field sources. This method is evaluated using close‐to‐real world data generated by a numerical electromagnetic tool, where the array and transmitter are placed in an irregular terrain and array data are generated using full 3‐D propagation model. It is shown that unknown source parameters can be estimated effectively showing the potential of the proposed approach in applications involving high‐frequency direction finding and indoor localization.
Large lakes as sources and sinks of anthropogenic heat: Capacities and limits
Authors: Fink Gabriel , Schmid Martin , Wüest Alfred
Published: August 2014

The goal of reducing carbon fuel and thereby saving energy will increase the use of lake water for heating and cooling of riparian infrastructures. This raises the question of which heat use designs meet the ecological and technical requirements for lakes, particularly in regard to climate warming. Thus, this study explores heat use effects on the temperature and stratification of a large, deep, temperate lake by applying the one‐dimensional k‐epsilon model SimStrat to various forcing scenarios. Several design parameters, such as extraction and discharge depth, and their effects were assessed. Additionally, 21st century climate projections were used to evaluate the effects of climate change relative to those of heat use. Generally, the study showed only minor effects for a realistic heat demand of ±2 W m−2 quite independent of the heat extraction/discharge modes. Mean water temperature changed less than ±0.2°C as long as there was no discharge into the deepest layers. Water extraction and discharge at the surface had the least thermal influence. To relate to climate change, heat use was scaled up to +85 W m−2. Resultant simulations showed that such (unrealistic) anthropogenic, lake‐based “thermal pollution” would have a comparable influence to that of climate change. Conversely, heat extraction could damp or even compensate climate‐induced warming. The present study concludes that (i) there are minor effects on water temperatures, stratification, and seasonal mixing due to heat use of up to ±2 W m−2 and (ii) those influences are insignificant relative to the expected climate change.
Layer‐by‐Layer Fabrication of Nanowire Sensitized Solar Cells: Geometry‐Independent Integration
Authors: Acharya Krishna P. , Ji Zhiqiang , Holesinger Terry G. , Crisp Jeffrey A. , Ivanov Sergei A. , Williams Darrick J. , Casson Joanna L. , Sykora Milan , Hollingsworth Jennifer A.
Published: August 2014

Thin film solar cells that are low in cost but still reasonably efficient comprise an important strategy for reaching price‐performance ratios competitive with fossil fuel electrical generation. Sensitized solar cells – most commonly dye but also semiconductor nanocrystal sensitized – are a thin film device option benefitting from lost cost material components and processing. Nanocrystal sensitized solar cells are predicted to outpace their dye‐based counterparts, but suffer from limited availability of approaches for integrating the nano‐sensitizers within a mesoporous oxide anode, which effectively limits the choice of sensitizer to those that are synthesized in situ or those that are easily incorporated into the oxide framework. The latter methods favor small, symmetric nanocrystals, while highly asymmetric semiconductors (e.g., nanowires, tetrapods, carbon nanotubes) have to date found limited utility in sensitized solar‐cell devices, despite their promise as efficient solar energy converters. Here, a new strategy for solar cell fabrication is demonstrated that is independent of sensitizer geometry. Nanocrystal‐sensitized solar cells are fabricated from either CdSe semiconductor quantum dots or nanowires with facile control over nanocrystal loading. Without substantial optimization and using low processing temperatures, efficiencies approaching 2% are demonstrated. Furthermore, the significance of a ‘geometry‐independent’ fabrication strategy is shown by revealing that nanowires afford important advantages compared to quantum dots as sensitizers. For equivalent nanocrystal masses and otherwise identical devices, nanowire devices yield higher power conversion efficiencies, resulting from both enhanced light harvesting efficiencies for all overlapping wavelengths and internal quantum efficiencies that are more than double those obtained for quantum dot devices.
An Experimental Insight into the Structural and Electronic Characteristics of Strontium‐Doped Titanium Dioxide Nanotube Arrays
Authors: Hamedani Hoda Amani , Allam Nageh K. , El‐Sayed Mostafa A. , Khaleel Mohammad A. , Garmestani Hamid , Alamgir Faisal M.
Published: August 2014

The possibility of in situ doping during electrochemical anodization of titania nanotube arrays is demonstrated and the mechanism and variations in structural and electronic characteristics of the nanotube arrays as after doping is systematically explored. In the presence of strontium as the dopant, bulk analysis shows strontium mainly incorporated into the lattice of TiO2. Surface analysis, however, reveals phase segregation of SrO in the TiO2 matrix at high Sr doping levels. The near edge X‐ray absorption fine structure (NEXAFS) spectroscopy analysis reveals that Sr2+ doping only alters the Ti and O ions interaction in the TiO2 lattice on the surface with no effect on their individual charge states. An in‐depth understanding of the dopant incorporation mechanism and distribution into TiO2 nanotube arrays is achieved using high resolution transmission electron microscopy (HRTEM) and the high angle annular dark‐field scanning transmission electron microscopy (HAADF‐STEM) coupled with the electron energy loss spectroscopy (EELS) measurements on the surface and bulk of the nanotubes. Upon their use to photoelectrochemically split water, the Sr‐doped TiO2 nanotube film shows incident photon conversion efficiencies (IPCE) as high as 65%. The enhanced light activity in conjunction with the ordered one‐dimensional morphology makes the fabricated films promising candidates for water photoelectrolysis.
A Tray‐Shaped, PdII‐Clipped Au3 Complex as a Scaffold for the Modular Assembly of [3×n] Au Ion Clusters
Authors: Osuga Takafumi , Murase Takashi , Hoshino Manabu , Fujita Makoto
Published: August 2014

A tray‐shaped PdII3AuI3 complex (1) is prepared from 3,5‐bis(3‐pyridyl)pyrazole by means of tricyclization with AuI followed by PdII clipping. Tray 1 is an efficient scaffold for the modular assembly of [3×n] AuI clusters. Treatment of 1 with the AuI3 tricyclic guest 2 in H2O/CH3CN (7:3) or H2O results in the selective formation of a [3×2] cluster (1⋅2) or a [3×3] cluster (1⋅2⋅1), respectively. Upon subsequent addition of AgI ions, these complexes are converted to an unprecedented Au3–Au3–Ag–Au3–Au3 metal ion cluster.
Synthesis and Isolation of an Acyclic Tridentate Bis(pyridine)carbodicarbene and Studies on Its Structural Implications and Reactivities
Authors: Hsu Yu‐Chen , Shen Jiun‐Shian , Lin Bo‐Chao , Chen Wen‐Ching , Chan Yi‐Tsu , Ching Wei‐Min , Yap Glenn P. A. , Hsu Chao‐Ping , Ong Tiow‐Gan
Published: August 2014

The simple synthetic development of acyclic pincer bis(pyridine)carbodicarbene is depicted herein. Presented is the first isolated structural pincer carbodicarbene with a C‐C‐C angle of 143°, larger than the monodentate framework. More importantly, theoretical analysis showed that this carbodicarbene embodies a more allene‐like character. Palladium complexes supported by this pincer ligand are active catalysts for Heck–Mizoroki and Suzuki–Miyaura coupling reactions.
Racemic and Quasi‐Racemic X‐ray Structures of Cyclic Disulfide‐Rich Peptide Drug Scaffolds
Authors: Wang Conan K. , King Gordon J. , Northfield Susan E. , Ojeda Paola G. , Craik David J.
Published: August 2014

Cyclic disulfide‐rich peptides have exceptional stability and are promising frameworks for drug design. We were interested in obtaining X‐ray structures of these peptides to assist in drug design applications, but disulfide‐rich peptides can be notoriously difficult to crystallize. To overcome this limitation, we chemically synthesized the L‐ and D‐forms of three prototypic cyclic disulfide‐rich peptides: SFTI‐1 (14‐mer with one disulfide bond), cVc1.1 (22‐mer with two disulfide bonds), and kB1 (29‐mer with three disulfide bonds) for racemic crystallization studies. Facile crystal formation occurred from a racemic mixture of each peptide, giving structures solved at resolutions from 1.25 Å to 1.9 Å. Additionally, we obtained the quasi‐racemic structures of two mutants of kB1, [G6A]kB1, and [V25A]kB1, which were solved at a resolution of 1.25 Å and 2.3 Å, respectively. The racemic crystallography approach appears to have broad utility in the structural biology of cyclic peptides.
A Cancer Therapeutic Vaccine based on Clustered Tn‐Antigen Mimetics Induces Strong Antibody‐Mediated Protective Immunity
Authors: Richichi Barbara , Thomas Baptiste , Fiore Michele , Bosco Rosa , Qureshi Huma , Nativi Cristina , Renaudet Olivier , BenMohamed Lbachir
Published: August 2014

Tumor‐associated carbohydrate antigens (TACAs) are key components of cancer vaccines. A variety of vaccines based on native TACAs such as α‐Tn have shown immunogenicity and protection in preclinical animal studies, however, their weak immunogenicity, low in vivo instability, and poor bioavailability, have discouraged their further evaluations in clinical studies. A new improved vaccine prototype is reported. It is composed of four clustered Tn‐antigen mimetics and a immunogenic peptide epitope that are conjugated to a cyclopeptide carrier. The immunization of mice with this vaccine 1) was safe, 2) induced a strong and long‐lasting Tn‐specific response with IgM/IgG antibodies able to recognize native carbohydrate antigens; 3) produced high titers of IgG1, IgG2a, and IgG3 antibodies; and 4) produced a significant antibody‐dependent regression of tumors and conferred protection. Altogether, these findings pave the way for the clinical development of safe and effective therapeutic vaccines against Tn‐expressing cancers.
Quality control in the polypropylene manufacturing process: An efficient, data‐driven approach
Authors: Cheng Zhong , Liu Xinggao
Published: August 2014

In the propylene polymerization process, the melt index (MI), as a critical quality variable in determining the product specification, cannot be measured in real time. What we already know is that MI is influenced by a large number of process variables, such as the process temperature, pressure, and level of liquid, and a large amount of their data are routinely recorded by the distributed control system. An alternative data‐driven model was explored to online predict the MI, where the least squares support vector machine was responsible for establishing the complicated nonlinear relationship between the difficult‐to‐measure quality variable MI and those easy‐to‐measure process variables, whereas the independent component analysis and particle swarm optimization technique were structurally integrated into the model to tune the best values of the model parameters. Furthermore, an online correction strategy was specially devised to update the modeling data and adjust the model configuration parameters via adaptive behavior. The effectiveness of the designed data‐driven approach was illustrated by the inference of the MI in a real polypropylene manufacturing plant, and we achieved a root mean square error of 0.0320 and a standard deviation of 0.0288 on the testing dataset. This proved the good prediction accuracy and validity of the proposed data‐driven approach. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2015, 132, 41312.
Dibenzo[a,f]perylene Bisimide: Effects of Introducing Two Fused Rings
Authors: Chaolumen  , Enno Hiroki , Murata Michihisa , Wakamiya Atsushi , Murata Yasujiro
Published: August 2014

Perylene bisimides (PBIs) are fascinating dyes with various potential applications. To study the effects of introducing a dibenzo‐fused structure to the perylene moiety, π‐extended PBI derivatives with a dibenzo‐fused structure at both of the a and f bonds were synthesized. The twisted structure was characterized by X‐ray crystal structure analysis. In the cyclic voltammograms, the dibenzo[a,f]‐fused PBI showed a reversible oxidation wave at much less positive potential, relative to a dibenzo[a,o]‐fused PBI derivative. These data indicated that two ring fusions at both sides of a naphthalene moiety, which construct a tetracene core, effectively raise the HOMO level compared to fusion of one ring at each naphthalene moiety (two anthracene cores). The dibenzo[a,f]‐fused PBI derivative showed an absorption band at 735 nm with a shoulder band reaching 900 nm.
Locked into the System? Critical Community Psychology Approaches to Personal Debt in the Context of Crises of Capital Accumulation
Authors: Walker Carl , Burton Mark , Akhurst Jacqui , Degirmencioglu Serdar M.
Published: August 2014

The considerable and sustained boom in personal debt recently has in many countries around the world led to experiences of over‐indebtedness that are associated with very considerable distress and suffering. This article explores critical perspectives that situate personal debt, material deprivation and suffering, and specific ways of knowing and acting, within the context of recent political and economic practices. There is a need to focus on positioning people's experiences of debt within a broader matrix of factors of national and international practices and policies, including globalisation, changing labour markets, and poorly regulated financial industries. These factors appear to have allowed a network of international financial institutions to adopt practices that have proved successful in creating personal debt. Yet, an individualised discourse of financial capability has been propagated, configuring personal debt as a problem of irresponsible individual consumption. In order to explore ways of resisting reactionary and individualised modes of addressing personal debt, proposals will be made of alternative paradigms for responding to personal debt, defined by two dimensions of community psychological practice, with examples. This article aims to increase collective awareness of the systemic character of debt and the collective responses required. Copyright © 2014 John Wiley & Sons, Ltd.
Engineering of Highly Selective Variants of Parvibaculum lavamentivorans Alcohol Dehydrogenase
Authors: Spickermann Dominik , Hausmann Sascha , Degering Christian , Schwaneberg Ulrich , Leggewie Christian
Published: August 2014

We present the development of highly selective variants of the Parvibaculum lavamentivorans alcohol dehydrogenase. Four amino acids (A158, N162, K202, L224) in the second sphere of the catalytic site were identified to determine the selectivity for 3‐quinuclidone reduction significantly. The best variant (A158H/N162G/K202Q/L224W) was able to increase the ee for (R)‐3‐quinuclidinol production from 84.3 % (wild‐type) to ≥99 % and concomitantly to enhance conversion by 43.5 %.
A First‐Principles Examination of the Asymmetric Induction Model in the Binap/RhI‐Catalysed 1,4‐Addition of Phenylboronic Acid to Cyclic Enones by Density Functional Theory Calculations
Authors: Qin Hua‐Li , Chen Xiao‐Qing , Huang Yi‐Zhen , Kantchev Eric Assen B.
Published: August 2014

First‐principles modelling of the diastereomeric transition states in the enantiodiscrimination stage of the catalytic cycle can reveal intimate details about the mechanism of enantioselection. This information can be invaluable for further improvement of the catalytic protocols by rational design. Herein, we present a density functional theory (IEFPCM/PBE0/DGDZVP level of theory) modelling of the carborhodation step for the asymmetric 1,4‐arylation of cyclic α,β‐unsaturated ketones mediated by a [(binap)RhI] catalyst. The calculations completely support the older, qualitative, pictorial model predicting the sense of the asymmetric induction for both the chelating diphosphane (binap) and the more recent chiral diene (Phbod) ligands, while also permitting quantification of the enantiomeric excess (ee). The effect of dispersion interaction correction and basis sets has been also investigated. Dispersion‐corrected functionals and solvation models significantly improve the predicted ee values.
Side‐Chain Engineering of Benzodithiophene‐Fluorinated Quinoxaline Low‐Band‐Gap Co‐polymers for High‐Performance Polymer Solar Cells
Authors: Xu Xiaopeng , Wu Yulei , Fang Junfeng , Li Zuojia , Wang Zhenguo , Li Ying , Peng Qiang
Published: August 2014

A new series of donor–acceptor co‐polymers based on benzodithiophene and quinoxaline with various side chains have been developed for polymer solar cells. The effect of the degree of branching and dimensionality of the side chains were systematically investigated on the thermal stability, optical absorption, energy levels, molecular packing, and photovoltaic performance of the resulting co‐polymers. The results indicated that the linear and 2D conjugated side chains improved the thermal stabilities and optical absorptions. The introduction of alkylthienyl side chains could efficiently lower the energy levels compared with the alkoxyl‐substituted analogues, and the branched alkoxyl side chains could deepen the HOMO levels relative to the linear alkoxyl chains. The branched alkoxyl groups induced better lamellar‐like ordering, but poorer face‐to‐face packing behavior. The 2D conjugated side chains had a negative influence on the crystalline properties of the co‐polymers. The performance of the devices indicated that the branched alkoxyl side chains improved the Voc, but decreased the Jsc and fill factor (FF). However, the 2D conjugated side chains would increase the Voc, Jsc, and FF simultaneously. For the first time, our work provides insight into molecular design strategies through side‐chain engineering to achieve efficient polymer solar cells by considering both the degree of branching and dimensionality.
Solvent‐Controlled Bifurcated Cascade Process for the Selective Preparation of Dihydrocarbazoles or Dihydropyridoindoles
Authors: Mo Dong‐Liang , Wink Donald J. , Anderson Laura L.
Published: August 2014

A solvent‐controlled cascade process has been identified for the dual purpose of the preparation of either dihydrocarbazoles or dihydropyridoindoles from identical N‐aryl‐α,β‐unsaturated nitrones and electron‐deficient allene starting materials. These reactions proceed smoothly under mild metal‐free conditions affording a range of two types of skeletally distinct indole‐based heterocycles in high yield and diastereoselectivity. These transformations demonstrate the use of a bifurcated cascade process that hinges on the ring‐opening event of a benzazepine intermediate for the synthesis of skeletally diverse heterocyclic products and rapid access to biologically‐significant, indole‐based structures.
3‐Rhoda‐1,2‐diazacyclopentanes: A Series of Novel Metallacycle Complexes Derived From CN Functionalization of Ethylene
Authors: Drover Marcus W. , Beh Daniel W. , Kennepohl Pierre , Love Jennifer A.
Published: August 2014

Rh‐containing metallacycles, [(TPA)RhIII(κ2‐(C,N)‐CH2CH2(NR)2‐]Cl; TPA=N,N,N,N‐tris(2‐pyridylmethyl)amine have been accessed through treatment of the RhI ethylene complex, [(TPA)Rh(η2‐CH2CH2)]Cl ([1]Cl) with substituted diazenes. We show this methodology to be tolerant of electron‐deficient azo compounds including azo diesters (RCO2NNCO2R; R=Et [3]Cl, R=iPr [4]Cl, R=tBu [5]Cl, and R=Bn [6]Cl) and a cyclic azo diamide: 4‐phenyl‐1,2,4‐triazole‐3,5‐dione (PTAD), [7]Cl. The latter complex features two ortho‐fused ring systems and constitutes the first 3‐rhoda‐1,2‐diazabicyclo[3.3.0]octane. Preliminary evidence suggests that these complexes result from N–N coordination followed by insertion of ethylene into a [Rh]N bond. In terms of reactivity, [3]Cl and [4]Cl successfully undergo ring‐opening using p‐toluenesulfonic acid, affording the Rh chlorides, [(TPA)RhIII(Cl)(κ1‐(C)‐CH2CH2(NCO2R)(NHCO2R)]OTs; [13]OTs and [14]OTs. Deprotection of [5]Cl using trifluoroacetic acid was also found to give an ethyl substituted, end‐on coordinated diazene [(TPA)RhIII(κ2‐(C,N)‐CH2CH2(NH)2‐]+ [16]Cl, a hitherto unreported motif. Treatment of [16]Cl with acetyl chloride resulted in the bisacetylated adduct [(TPA)RhIII(κ2‐(C,N)‐CH2CH2(NAc)2‐]+, [17]Cl. Treatment of [1]Cl with AcNNAc did not give the RhN insertion product, but instead the N,O‐chelated complex [(TPA)RhI(κ2‐(O,N)‐CH3(CO)(NH)(NC(CH3)(OCHCH2))]Cl [23]Cl, presumably through insertion of ethylene into a [Rh]O bond.
Universal Reaction Mechanism of Boronic Acids with Diols in Aqueous Solution: Kinetics and the Basic Concept of a Conditional Formation Constant
Authors: Furikado Yuki , Nagahata Tomomi , Okamoto Takuya , Sugaya Tomoaki , Iwatsuki Satoshi , Inamo Masahiko , Takagi Hideo D. , Odani Akira , Ishihara Koji
Published: August 2014

To establish a detailed reaction mechanism for the condensation between a boronic acid, RB(OH)2, and a diol, H2L, in aqueous solution, the acid dissociation constants (${K{{{\rm BL}\hfill \atop {\rm a}\hfill}}}$) of boronic acid diol esters (HBLs) were determined based on the well‐established concept of conditional formation constants of metal complexes. The pKa values of HBLs were 2.30, 2.77, and 2.00 for the reaction systems, 2,4‐difluorophenylboronic acid and chromotropic acid, 3‐nitrophenylboronic acid and alizarin red S, and phenylboronic acid and alizarin red S, respectively. A general and precise reaction mechanism of RB(OH)2 with H2L in aqueous solution, which can serve as a universal reaction mechanism for RB(OH)2 and H2L, was proposed on the basis of (a) the relative kinetic reactivities of the RB(OH)2 and its conjugate base, that is, the boronate ion, toward H2L, and (b) the determined pKa values of HBLs. The use of the conditional formation constant, K′, based on the main reaction: RB(OH)2+H2L ${{\mathop \leftrightarrow \limits ^{K{_{1}}}_{}}}$ RB(L)(OH)−+H3O+ instead of the binding constant has been proposed for the general reaction of uncomplexed boronic acid species (B′) with uncomplexed diol species (L′) to form boronic acid diol complex species (esters, BL′) in aqueous solution at pH 5–11: B′+L′ ${{\mathop \leftrightarrow \limits ^{K{^\prime}}_{}}}$ BL′. The proposed reaction mechanism explains perfectly the formation of boronic acid diol ester in aqueous solution.
Assessments of Semilocal Density Functionals and Corrections for Carbon Dioxide Adsorption on Metal–Organic Frameworks
Authors: Ji Hyunjun , Park Joonho , Cho Moses , Jung Yousung
Published: August 2014

The significant amount of attention that has been directed toward metal–organic frameworks (MOFs) for a wide spectrum of applications can be attributed to their variety and tunability, which are precisely the aspects that computational modeling can offer by systematically exploring the chemical space. In this minireview, we describe density functional theory calculations for gas adsorption on MOFs, mainly focusing on the interaction of CO2 with MOF‐74. The generalized gradient approximation (GGA) level of density functional studies seems suited to treat MOFs, owing to the balance between its practical applicability and its useful accuracy, although this method is not without deficiencies such as the lack of nonlocal correlations and self‐interactions. We review and analyze the effects of correction schemes to the GGA to amend the latter weaknesses, and the choice of exchange correlation functionals to treat MOFs for gas capture and separation. We also discuss a few topical questions that are currently missing in the present literature and that require further investigations.
FAK Is required for c‐Met/β‐catenin‐driven hepatocarcinogenesis
Authors: Shang Na , Arteaga Maribel , Zaidi Ali , Stauffer Jimmy , Cotler Scott J. , Zeleznik‐Le Nancy J. , Zhang Jiwang , Qiu Wei
Published: August 2014

Hepatocellular carcinoma (HCC) is the third most common cause of cancer death worldwide and most patients with HCC have limited treatment options. Focal adhesion kinase (FAK) is overexpressed in many HCC specimens, offering a potential target for HCC treatment. However, the role of FAK in hepatocarcinogenesis remains elusive. Establishing whether FAK expression plays a role in HCC development is necessary to determine whether it is a viable therapeutic target. In this study, we generated mice with hepatocyte‐specific deletion of Fak and investigated the role of Fak in an oncogenic (c‐MET/β‐catenin, MET/CAT)‐driven HCC model. We found that deletion of Fak in hepatocytes did not affect morphology, proliferation, or apoptosis. However, Fak deficiency significantly repressed MET/CAT‐induced tumor development and prolonged survival of animals with MET/CAT‐induced HCC. In mouse livers and HCC cell lines, Fak was activated by MET, which induced the activation of Akt/Erk and up‐regulated cyclin D1 and tumor cell proliferation. CAT enhanced MET‐stimulated FAK activation and synergistically induced the activation of the AKT/ERK‐cyclin D1 signaling pathway in a FAK kinase‐dependent manner. In addition, FAK was required for CAT‐induced cyclin D1 expression in a kinase‐independent fashion. Conclusion: Fak is required for c‐Met/β‐catenin‐driven hepatocarcinogenesis. Inhibition of FAK provides a potential strategy to treat HCC. (Hepatology 2015;61:214–226)
Applicability of density functional theory in reproducing accurate vibrational spectra of surface bound species
Authors: Matanović Ivana , Atanassov Plamen , Kiefer Boris , Garzon Fernando H. , Henson Neil J.
Published: August 2014

The structural equilibrium parameters, the adsorption energies, and the vibrational frequencies of the nitrogen molecule and the hydrogen atom adsorbed on the (111) surface of rhodium have been investigated using different generalized‐gradient approximation (GGA), nonlocal correlation, meta‐GGA, and hybrid functionals, namely, Perdew, Burke, and Ernzerhof (PBE), Revised‐RPBE, vdW‐DF, Tao, Perdew, Staroverov, and Scuseria functional (TPSS), and Heyd, Scuseria, and Ernzerhof (HSE06) functional in the plane wave formalism. Among the five tested functionals, nonlocal vdW‐DF and meta‐GGA TPSS functionals are most successful in describing energetics of dinitrogen physisorption to the Rh(111) surface, while the PBE functional provides the correct chemisorption energy for the hydrogen atom. It was also found that TPSS functional produces the best vibrational spectra of the nitrogen molecule and the hydrogen atom on rhodium within the harmonic formalism with the error of −2.62 and −1.1% for the NN stretching and RhH stretching frequency. Thus, TPSS functional was proposed as a method of choice for obtaining vibrational spectra of low weight adsorbates on metallic surfaces within the harmonic approximation. At the anharmonic level, by decoupling the RhH and NN stretching modes from the bulk phonons and by solving one‐ and two‐dimensional Schrödinger equation associated with the RhH, RhN, and NN potential energy we calculated the anharmonic correction for NN and RhH stretching modes as −31 cm−1 and −77 cm−1 at PBE level. Anharmonic vibrational frequencies calculated with the use of the hybrid HSE06 function are in best agreement with available experiments. © 2014 Wiley Periodicals, Inc.
Photocatalytic oxidation of cytostatic drugs by microwave‐treated N‐doped TiO2 under visible light
Authors: Lin Hank Hui‐Hsiang , Lin Angela Yu‐Chen , Hung Chia‐Lin
Published: August 2014

BACKGROUND

5‐Fluorouracil is one of the most commonly used cytostatic drugs worldwide. However, the toxicity and persistence of 5‐fluorouracil in the environment have recently received considerable attention. In this study, 5‐fluorouracil removal was performed by photocatalytic oxidation with microwave‐treated N‐doped TiO2 under visible light.

RESULTS

The microwave‐treated N‐doped TiO2 removed 5‐fluorouracil with a higher degradation efficiency than N‐doped TiO2 synthesized with the traditional thermal treatments. The most efficient N‐doped TiO2 (N6) was synthesized using 1 M NH4OH pre‐immersion and a 3 h 180°C microwave treatment, followed by 55°C calcination for 6 h. The photocatalytic degradation of 5‐fluorouracil achieved 88.8% removal within 20 h of treatment by N6 under visible light, which is higher than that obtained by Degussa P25 TiO2 (61.5%). Higher concentrations of NH4OH and longer calcination times resulted in decreased 5‐fluorouracil degradation; the particle size of the synthesized N‐doped TiO2 increased after calcination. The surface area decreased while the pore volume and pore size increased after synthesis. Furthermore, the basicity of the sites on the synthesized N‐doped TiO2 decreased after calcination.

CONCLUSION

This study, for the first time, reported that microwave‐assisted treatment for N‐doped TiO2 synthesis effectively removed 5‐fluorouracil and cyclophosphamide compared with traditional thermal treatment. © 2014 Society of Chemical Industry
A first demonstration and analysis of the biprimary color system for reflective displays
Authors: Mukherjee Sayantika , Smith Nathan , Goulding Mark , Topping Claire , Norman Sarah , Liu Qin , Kramer Laura , Kularatne Senal , Heikenfeld Jason
Published: August 2014

A new biprimary color system is demonstrated for single‐layer reflective displays, capturing much of the improved color performance of multilayer displays while potentially maintaining single‐layer display advantages in high resolution and faster switching. Electrophoretic pixels were operated with dual‐particle complementary‐colored dispersions such as green/magenta (G/M). Using simple interdigitated three‐electrode architecture, four colored states (KWGM) were achieved with a preliminary contrast ratio of 10 : 1. Furthermore, biprimary ink dispersions were shown to be functional in a more advanced electrokinetic pixel structure. A full‐color biprimary pixel contains three complementary subpixels (G/M, B/Y, R/C), and the requisite electrophoretic ink dispersions were also formulated and spectrally characterized in this work. Lastly, theoretical color space mapping confirms that the biprimary concept provides twice the brightness and twice the color fraction compared with the conventional RGBW subpixel approach, and that the biprimary concept can approach performance close to that of magazine print (Specifications for Web‐Offset Print).
Sharpness and noise characteristics of a half‐mirror stereoscopic display
Authors: Yamazaki Asumi , Marini‐Bettolo Cecilia , Kodera Yoshie , Badano Aldo
Published: August 2014

Stereoscopic displays are becoming popular in entertainment and industrial applications. We characterize the spatial resolution and noise properties of a stereoscopic display with a half‐mirror and passive polarizing glasses. The upper display images reflected off the mirror have slightly degraded sharpness and reduced high spatial‐frequency noise resulting in modulation transfer functions (MTFs) of 0.59 and 0.50 at the Nyquist frequency with corresponding noise power spectra (NPS) values of 4.79 × 10−6 and 5.17 × 10−6 mm2 at 10 mm−1 in the horizontal and vertical directions. These results are compared to the characteristics of the individual displays with MTF values of 0.64 and 0.53 and NPS values of 6.24 × 10−6 and 5.87 × 10−6 mm2. The polarizing glasses cause minimal reduction in sharpness and high‐frequency noise. The MTFs in the upper images observed with glasses are decreased to 0.54 and 0.47, while the NPS are decreased to 2.86 × 10−6 and 2.01 × 10−6 mm2. When both displays are turned on and using the mirror and glasses, the observed luminance for each eye is increased from the luminance of the individual displays owing to crosstalk. We find that sharpness and noise are not affected by the interaction between the displays at the particular geometry tested in this study.
iPP–sPP Stereoblocks or Blends? Studies on the Synthesis of Isotactic–Syndiotactic Polypropylene Using Single C1‐Symmetric {Ph2C‐(Flu)(3‐Me3Si‐Cp)}ZrR2 Metallocene Precatalysts
Authors: Theurkauff Gabriel , Roisnel Thierry , Waassenaar Jeroen , Carpentier Jean‐François , Kirillov Evgeny
Published: August 2014

Single isoselective C1‐symmetric {Ph2C‐(Flu)(3‐Me3Si‐Cp)}ZrR2 (R = Cl (1b), Me (2b)) metallo­cene precatalysts, upon activation with MAO or [PhNMe2H]+[B(C6F5)4]−/iBu3Al, produce isotactic polypropylene (PP) (up to 80% mmmm), which is more enriched with syndiotactic pentads (0.9–2.2% rrrr) than the statistical model assumes. Similar or even more syndiotactically enriched PPs (3.0–25.4% rrrr) are obtained using combinations of 1b or 2b with Cs‐symmetric syndioselective {Ph2C‐(Flu)(Cp)}ZrR2 (R = Cl (1a), Me (2a)) metallo­cenes. While NMR spectroscopy, differential scanning calorimetry (DSC), and gel per­meation chromatography (GPC) analyses do not provide explicit evidence on the nature of these polymers, temperature rising elution fractionation (TREF) unambiguously identifies them as blends of iPP and sPP polymers and not discrete iPP−b−sPP stereoblock copolymers. The formation of sPP fractions from the a priori isoselective 1b and 2b systems is attributed to a desilylation side reaction, which takes place in the precatalyst synthesis step and possibly also during the polymerization, resulting in the generation of the Me3Si‐free syndioselective catalytically active species. Activation of 2a with B(C6F5)3 and [PhNMe2H]+[B(C6F5)4]− selectively leads to the corresponding cationic complexes 3a and 4a, as confirmed by NMR spectroscopic methods and the solid‐state structure of {Ph2C‐(Flu)(Cp)}ZrMe(μ‐Me)B(C6F5)3 (3a). On the other hand, the activation of 2b with the same molecular activators is less selective, and the formation of the corresponding cationic products 3b and 4b along with unidentified impurities is monitored by NMR spectroscopy. A possible chain‐shuttling process between isoselective and syndioselective active species, mediated by Me3Al or iBu3Al, appears to be inoperative under given conditions.

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k‐t FASTER: Acceleration of functional MRI data acquisition using low rank constraints
Authors: Chiew Mark , Smith Stephen M. , Koopmans Peter J. , Graedel Nadine N. , Blumensath Thomas , Miller Karla L.
Published: August 2014

Purpose

In functional MRI (fMRI), faster sampling of data can provide richer temporal information and increase temporal degrees of freedom. However, acceleration is generally performed on a volume‐by‐volume basis, without consideration of the intrinsic spatio‐temporal data structure. We present a novel method for accelerating fMRI data acquisition, k‐t FASTER (FMRI Accelerated in Space‐time via Truncation of Effective Rank), which exploits the low‐rank structure of fMRI data.

Theory and Methods

Using matrix completion, 4.27× retrospectively and prospectively under‐sampled data were reconstructed (coil‐independently) using an iterative nonlinear algorithm, and compared with several different reconstruction strategies. Matrix reconstruction error was evaluated; a dual regression analysis was performed to determine fidelity of recovered fMRI resting state networks (RSNs).

Results

The retrospective sampling data showed that k‐t FASTER produced the lowest error, approximately 3–4%, and the highest quality RSNs. These results were validated in prospectively under‐sampled experiments, with k‐t FASTER producing better identification of RSNs than fully sampled acquisitions of the same duration.

Conclusion

With k‐t FASTER, incoherently under‐sampled fMRI data can be robustly recovered using only rank constraints. This technique can be used to improve the speed of fMRI sampling, particularly for multivariate analyses such as temporal independent component analysis. Magn Reson Med 74:353–364, 2015. © 2014 The Authors Magnetic Resonance in Medicine published by Wiley Periodicals, Inc. on behalf of International Society for Magnetic Resonance in Medicine. This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.
Hyperpolarized 13C NMR detects rapid drug‐induced changes in cardiac metabolism
Authors: Khemtong Chalermchai , Carpenter Nicholas R. , Lumata Lloyd L. , Merritt Matthew E. , Moreno Karlos X. , Kovacs Zoltan , Malloy Craig R. , Sherry A. Dean
Published: August 2014

Purpose

The diseased myocardium lacks metabolic flexibility and responds to stimuli differently compared with healthy hearts. Here, we report the use of hyperpolarized 13C NMR spectroscopy to detect sudden changes in cardiac metabolism in isolated, perfused rat hearts in response to adrenergic stimulation.

Methods

Metabolism of hyperpolarized [1‐13C]pyruvate was investigated in perfused rat hearts. The hearts were stimulated in situ by isoproterenol shortly after the administration of hyperpolarized [1‐13C]pyruvate. The hyperpolarized 13C NMR results were corroborated with 1H NMR spectroscopy of tissue extracts.

Results

Addition of isoproterenol to hearts after equilibration of hyperpolarized [1‐13C]pyruvate into the existing lactate pool resulted in a sudden, rapid increase in hyperpolarized [1‐13C]lactate signal within seconds after exposure to drug. The hyperpolarized H13CO3− and hyperpolarized [1‐13C]alanine signals were not affected by the isoproterenol‐induced elevated cardiac workload. Separate experiments confirmed that the new hyperpolarized [1‐13C]lactate signal that arises after stimulation by isoproterenol reflects a sudden increase in total tissue lactate derived from glycogen.

Conclusion

These results suggest that hyperpolarized pyruvate and 13C MRS may be useful for detecting abnormal glycogen metabolism in intact tissues. Magn Reson Med 74:312–319, 2015. © 2014 Wiley Periodicals, Inc.
In Vivo Studies of Nanostructure‐Based Photosensitizers for Photodynamic Cancer Therapy
Authors: Voon Siew Hui , Kiew Lik Voon , Lee Hong Boon , Lim Siang Hui , Noordin Mohamed Ibrahim , Kamkaew Anyanee , Burgess Kevin , Chung Lip Yong
Published: August 2014

Animal models, particularly rodents, are major translational models for evaluating novel anticancer therapeutics. In this review, different types of nanostructure‐based photosensitizers that have advanced into the in vivo evaluation stage for the photodynamic therapy (PDT) of cancer are described. This article focuses on the in vivo efficacies of the nanostructures as delivery agents and as energy transducers for photosensitizers in animal models. These materials are useful in overcoming solubility issues, lack of tumor specificity, and access to tumors deep in healthy tissue. At the end of this article, the opportunities made possible by these multiplexed nanostructure‐based systems are summarized, as well as the considerable challenges associated with obtaining regulatory approval for such materials. The following questions are also addressed: (1) Is there a pressing demand for more nanoparticle materials? (2) What is the prognosis for regulatory approval of nanoparticles to be used in the clinic?