bluuebunny/crossref_metadata_2025_split huggingface dataset:
Participation civique et politique des citoyens issus de l’immigration
Authors: Simard Carolle , Pagé Michel 
Published: September 2018

Dans cet article, nous présentons les conclusions d’une enquête exploratoire réalisée auprès de nouveaux citoyens canadiens originaires de pays non démocratiques. Sont notamment étudiées les variables susceptibles d’expliquer leurs perceptions des systèmes politiques canadien et québécois ainsi que leurs comportements politiques. Plus particulièrement, nous nous intéressons aux interrelations entre ces trois groupes de variables : politiques, psychologiques et sociodémographiques. Notre étude s’appuie sur l’analyse de 30 entretiens semi-directifs complétés auprès de répondants montréalais nés en Haïti, au Liban et au Pérou.
Raman Spectroscopy of Proteins and Nucleic Acids: From Amino Acids and Nucleotides to Large Assemblies
Authors: Krafft Christoph 
Published: September 2018

AbstractNucleic acids and proteins are important biomolecules in all living organisms. Here, the principles are summarized to analyze Raman spectra of nucleic acids, proteins, and complexes of proteins and lipids in solutions and in crystallized form. These principles are transferred to Raman analysis of cells and tissues that contain spectral contributions of proteins and nucleic acids. Raman images of cells are able to resolve subcellular features with distinct spectral signatures. Raman images of tissues are able to resolve cellular features. In general, Raman spectra provide a phenotypic fingerprint for the cell type and tissue type, and cell‐ and tissue‐associated processes and pathologies. The knowledge about the assignment of protein and nucleic acid bands is the key to understand the underlying molecular variations. Tables are compiled for bands of protein secondary structures, bands of nucleotides, and bands of nucleic acids conformations. Figures present Raman spectra of (i) aromatic amino acids phenylalanine, tyrosine and tryptophan, (ii) proteins bovine serum albumin, concanavalin A and collagen, (iii) DNA and RNA, (iv) protein–DNA complexes, (v) nucleus and cytoplasm of cells, (vi) nucleic acid and protein distribution in dried and nondried tissue sections, and (vii) segmentation of various tissue types in colon cross section.
Photodissociation Mass Spectrometry of Peptides and Proteins
Authors: Julia Bauzá‐Martinez , de Oliveira Eliandre 
Published: September 2018

AbstractPhotodissociation has been extensively explored in the last decades for the analysis of peptides and proteins by mass spectrometry (MS). In the photodissociation process, ions interact with photons generating an increment on internal energy that leads to their fragmentation. The specific characteristics of photodissociation techniques have led to improvements in different applications of MS. Among them, the cleavage of molecular bonds in a selective manner, based on the incorporation of chromophore molecules. Moreover, the ability to generate an almost complete array of fragment ions is the main reason for the increment in the utilization of ultraviolet photodissociation (UVPD). This technique has been applied to the most challenging proteomics studies, such as the characterization of posttranslational modifications and protein sequence variations, de novo sequencing, and the analysis of intact proteins. This article is focused on the most recent and relevant developments of infrared photodissociation and UVPD techniques and their application to the study of peptides and proteins.
Impact of a novel exponential weighted 4DCT reconstruction algorithm
Authors: Morris Eric D. , Kim Joshua P. , Klahr Paul , Glide‐Hurst Carri K. 
Published: September 2018

AbstractPurposeThis work characterizes a novel exponential 4DCT reconstruction algorithm (EXPO), in phantom and patient, to determine its impact on image quality as compared to the standard cosine‐squared weighted 4DCT reconstruction.MethodsA motion platform translated objects in the superior–inferior (S‐I) direction at varied breathing rates (8–20 bpm) and couch pitches (0.06–0.1) to evaluate interplay between parameters. Ten‐phase 4DCTs were acquired and data were reconstructed with cosine squared and EXPO weighting. To quantify the magnitude of image blur, objects were translated in the anterior–posterior (A‐P) and S‐I directions for full‐width half maximum (FWHM) analysis between both 4DCT algorithms and a static case. 4DCT sinogram data for 10 patients were retrospectively reconstructed using both weighting factors. Image subtractions elucidated intensity and boundary differences. Subjective image quality grading (presence of image artifacts, noise, spatial resolution (i.e., lung/liver boundary sharpness), and overall image quality) was conducted yielding 200 evaluations.ResultsAfter taking static object size into account, the FWHM of EXPO reconstructions in the A‐P direction was 3.3 ± 1.7 mm (range: 0–4.9) as compared to cosine squared 9.8 ± 4.0 mm (range: 2.6–14.4). The FWHM of objects translated in the S‐I direction reconstructed with EXPO agreed better with the static FWHM than the cosine‐squared reconstructions. Slower breathing periods, faster couch pitches, and intermediate 4DCT phases had the largest reductions of blurring with EXPO. 18 of 60 comparisons of artifacts were improved with EXPO reconstruction, whereas no appreciable changes were observed in image quality scores. In 18 of 20 cases, EXPO provided sharper images although the reduced projections also increased baseline noise.ConclusionExponential weighted 4DCT offers potential for reducing image blur (i.e., improving image sharpness) in 4DCT with a tendency to reduce artifacts. Future work will involve evaluating the impact on treatment planning including delineation ability and dose calculation.
Marching Toward Highly Efficient, Pure‐Blue, and Stable Thermally Activated Delayed Fluorescent Organic Light‐Emitting Diodes
Authors: Cai Xinyi , Su Shi‐Jian 
Published: September 2018

AbstractThe vast market demands for applications of organic light‐emitting diodes (OLEDs) have quickened the pace of the search for future high‐performance materials, emphasizing the importance of exploring blue light‐emitting materials, which determine the performance bottleneck of OLEDs. Moreover, actualizing highly efficient, pure‐blue, stable, and purely organic electroluminescence will pave the way toward the realization of cost‐effective, high‐quality, and long‐lasting commercialized OLED displays and illumination applications. Without the aid of noble heavy metal atoms, the newly emerging thermally activated delayed fluorescent (TADF) materials can effectively utilize triplet excitons owing to the small singlet–triplet splitting energy (ΔEST) for rapid reverse intersystem crossing (RISC) process, leading to the achievement of 100% internal quantum efficiency under electrical operation. Nevertheless, fundamental scientific challenges with respect to simultaneously achieving stable pure‐blue emission, large radiative recombination rates with short exciton lifetimes and small ΔEST continue to hinder the popularization of blue TADF materials. A review of the current state of blue TADF emitters is timely and underscores the key challenges that must be overcome toward the development of a stable, true‐blue TADF‐based electroluminescent application in the future.
Environmental Stimuli‐Irresponsive Long‐Term Radical Scavenging of 2D Transition Metal Dichalcogenides through Defect‐Mediated Hydrogen Atom Transfer in Aqueous Media
Authors: Kim Ji Eun , Yim DaBin , Lee Chi Ho , Jun Byeongsun , Nam Jin , Han Sang Hoon , Lee Sang Uck , Kim Jong‐Ho , Kim Jin Woong 
Published: September 2018

AbstractA transition metal dichalcogenide (TMD) based antioxidation platform is proposed, in which radical scavenging is accomplished by the defect‐mediated one‐step hydrogen atom transfer (HAT) occurring on the nanosheets in water. To this end, the TMD nanosheets, including MoS2, WS2, MoSe2, and WSe2, are finely dispersed in water with the aid of an amphiphilic poly(ε‐caprolactone)‐b‐poly(ethylene oxide) (PCL‐b‐PEO) diblock copolymer that envelops the nanosheets with a molecular layer of less than 1 nm thickness. It is then demonstrated that the PCL‐b‐PEO‐stabilized TMD nanosheets show the extraordinarily enhanced and prolonged radical scavenging activity in water even under harsh storage conditions. Theoretical modeling studies on HAT suggest that more favorable hydrogen association from chalcogen vacancies on the nanosheets dispersed in water can lead to the easier dissociation of hydrogen atoms with exothermicity by −0.43 to −1.33 eV, thus exhibiting such an outstanding radical scavenging performance.
General Construction of Molybdenum‐Based Nanowire Arrays for pH‐Universal Hydrogen Evolution Electrocatalysis
Authors: Zhang Xing , Zhou Feng , Pan Weiying , Liang Yongye , Wang Ruihu 
Published: September 2018

AbstractRobustly integrated electrodes constructed by well‐organized building blocks of active materials are appealing in versatile electrochemical systems. Herein, orderly oriented nanowire arrays (NWAs) of multiple molybdenum‐based compounds (MoXn, MoXn = MoP, MoS2, Mo2C, MoN, and MoO2) on carbon fiber paper (CFP) are generally fabricated by topotactic transformations from molybdenum‐containing precursor NWAs. Extensive structural characterizations reveal that these MoXn nanowires are composed of either closely interconnected nanoparticles or edge‐rich nanosheets. When being used as self‐supported electrodes, these MoXn NWAs/CFP exhibit excellent catalytic activities and stabilities toward hydrogen evolution reaction (HER) in pH‐universal electrolytes. Especially, the best‐performed MoP NWAs/CFP shows comparable or even superior HER performance over platinum benchmark, which holds great promises in HER‐related energy technologies. This work presents a simple yet effective approach toward general synthesis of self‐supported Mo‐based NWAs on CFP, which also possesses huge application prospects in other fields, such as supercapacitors, batteries, and sensors.
Energy Materials Design for Steering Charge Kinetics
Authors: Zhang Guozhen , Yang Li , Wang Xijun , Wu Ziye , Jiang Jun , Luo Yi 
Published: September 2018

AbstractCharge kinetics is a critical factor that determines working efficiencies of energy materials in their various applications. It is governed by electronic structures of the materials of interest and can be fine‐tuned via purposeful adjustment of electronic structures. Recent advances in the development of energy materials with desirable electronic structures to steering charge kinetics toward specific applications are highlighted here. Two key strategies are presented: one is through the tuning of energy states and the other is to control spatial distributions of charges. Each strategy is described by several different schemes. Finally, the challenges and perspectives in designing energy materials with fine control of charge kinetics are discussed.
Epitaxial Growth of Few‐Layer Black Phosphorene Quantum Dots on Si Substrates
Authors: Xu Hao , Han Xiaoyu , Li Zhuangnan , Liu Wei , Li Xiao , Wu Jiang , Guo Zhengxiao , Liu Huiyun 
Published: September 2018

AbstractElemental 2D materials, such as silicene, germanene, and stanene, are synthesized by molecular beam epitaxy (MBE). However, the epitaxial growth of black phosphorene is challenging to date. Herein, the successful MBE growth of few‐layer black phosphorene quantum dots (BPQDs) directly on Si substrates at relatively low temperature using white phosphorus as the precursor is reported. The formation of black phosphorene is confirmed by atomic force microscopy, X‐ray photoelectron spectroscopy, and Raman spectroscopy, in combination with density functional theory (DFT) calculations. Uniform and pyramid‐shaped BPQDs with an average radius of 27.5 ± 5 nm and height of 3.1 ± 0.6 nm are obtained at surface steps on fully deoxidized Si(111) substrates. The growth mechanism is probed by DFT at atomic level, demonstrating the crystallization of BPQDs at steps in preference to terraces on Si substrates of (111) and (100) surfaces. The results show that BPQDs follow the Frank‐van der Merwe growth mode and the favored few‐layer growth trend with pyramid configuration. The realization of MBE‐grown BPQDs enables the synthesis of inch‐sized low‐dimensional black phosphorus with high purity and crystallinity, particularly promising for nanoelectronics and optoelectronics.
Ti‐Substituted Keggin‐Type Polyoxotungstate as Proton and Electron Reservoir Encaged into Metal–Organic Framework for Carbon Dioxide Photoreduction
Authors: Liu Shu‐Mei , Zhang Zhong , Li Xiaohui , Jia Hongjie , Ren Mingwen , Liu Shuxia 
Published: September 2018

AbstractA key challenge for photocatalystic CO2 reduction is the design and synthesis of photocatalyst with remarkable performance in visible‐light absorption, CO2 adsorption, and electron‐coupled proton transfer. Here a visible light–driven hybrid photocatalyst Au@NENU‐10, consisting of Au nanoparticles (NPs), Ti‐substituted keggin‐type polyoxometalate [PTi2W10O40]7− (PTiW), and HKUST‐1, is synthesized by the one‐pot method at atmosphere condition where PTiW acts as both electrons' and protons' reservoir, and a reactive active center is encaged into HKUST‐1 to boost CO2 reduction, HKUST‐1 as a microreactor to concentrate CO2 molecules, and Au NPs harvesting visible light. Notably, compared to [PW12O40]3−‐encaged HKUST‐1 (NENU‐3) with an octahedron shape, the Ti‐substituted counterpart of NENU‐10 shows a cube shape with a little corner cut, which is ascribed to the higher net charge on terminal oxygen atoms of PTiW, slowing down the crystal growth along the 〈100〉 direction. Moreover, PTiW always exposes on {100} plane of HKUST‐1 in the synthesis process, stabilizing Au NPs and thus being dispersed evenly in NENU‐10. Owing to the stronger protonation of TiO and TiOW, Au@NENU‐10 shows higher CO2 reduction activity and selectivity under visible‐light irradiation (λ > 420 nm), about 85.3‐fold and 5.2‐fold enhancement, respectively, corresponding to the CO2‐to‐CO and CO2‐to‐H2 conversion in contrast to Au@NENU‐3.
Large Thermal Conductivity Switch Ratio in Barium Titanate Under Electric Field through First‐Principles Calculation
Authors: Liu Chenhan , Mishra Vivek , Chen Yunfei , Dames Chris 
Published: September 2018

AbstractThe thermal conductivity of crystalline materials is typically one or two orders of magnitude higher than that of their amorphous structures. The phase transition in barium titanate is generally considered to exhibit order–disorder character, suggesting the potential for thermal conductivity switching if this order–disorder transition can be controlled. To investigate this possibility computationally, following the method of Fu and Bellaiche, here electric fields are applied to align the polarizations and transform disordered paraelectric structures to ordered ferroelectric structures. Solving the Boltzmann transport equation, the theoretical limit of a perfectly disordered structure is found to have thermal conductivity of a factor of 3.9 lower than the perfectly ordered structure. The thermal conductivity of the ordered structure can be further enhanced by up to another 2.4 times under electric fields due to the reduction in phonon scattering rates, implying a theoretical maximum thermal conductivity switching ratio of 9.4. This study yields two guidelines in searching for high thermal conductivity switch ratio in ferroelectric materials: the structure should be single domain under electric field and the phase transition should be fully order–disorder rather than displacive.
Effect of Water, Oxygen, and Air Exposure on CH3NH3PbI3–xClx Perovskite Surface Electronic Properties
Authors: Ralaiarisoa Maryline , Salzmann Ingo , Zu Feng‐Shuo , Koch Norbert 
Published: September 2018

AbstractThe stability of hybrid perovskite materials for solar cells and high surface property reproducibility are important topics of present research. To understand the impact of water, oxygen, and air exposure, as experienced during typical device fabrication and operation conditions, on the surface electronic properties of solution‐processed CH3NH3PbI3–xClx perovskite thin films, and subsequently formed interfaces to other materials, a comprehensive photoelectron spectroscopy study is performed. It is shown that pure oxygen exposure reduces the typically observed pronounced n‐type surface character, while pure water exposure increases it. Very low water partial pressure, e.g., as encountered in inert‐gas glove boxes and in high vacuum of 10−6 mbar, reduces the perovskite work function due to water physisorption, which is fully reversible upon mild annealing (room temperature to 50 °C) in ultrahigh vacuum. Upon exposure to ambient air, the effect of oxygen prevails over that of water, and the perovskite become less n‐type as seen by a 0.6 eV Fermi level shift toward midgap. The results help in understanding variations of the surface electronic properties reported for perovskites, which in turn impact the energy level alignment at heterojunctions in devices. For future studies, the crucial importance of stringent environment control is stressed upon.
Closing Information Gaps in Kakuma Refugee Camp: A Youth Participatory Action Research Study
Authors: Bellino Michelle J. ,   the Kakuma Youth Research Group
Published: September 2018

AbstractThis study explores the role of academic and social support on young people's educational pursuits in Kenya's Kakuma Refugee Camp. Pairing ethnographic methods with youth participatory action research, we find that support often manifests as abstract, decontextualized encouragement with little grounding in the educational opportunity structure. We argue that this motivational discourse generates information gaps, fueling aspirations that neither prepare youth for understanding, nor navigating the constraints they will encounter. In response, we designed a social media platform orienting Kakuma youth to the opportunity structure, while encouraging them to set realistic goals and plan accordingly. Designing a resource by, for, and with Kakuma youth, we illustrate that refugees have the rights and means to access information on which their everyday well‐being and futures depend. This study illustrates that critical understanding of local and global opportunities can empower, rather than demoralize, young people as they shape their futures in exile.
Enabling Lasing Action in Hybrid Atomic–Nanophotonic Integrated Structures
Authors: Alaeian Hadiseh , Odom Brian C. , Bravo‐Abad Jorge 
Published: September 2018

AbstractThe incorporation of neutral atoms in nanophotonic structures offers significant potential to realize novel quantum optical devices. Here, the possibility of creating low‐threshold integrated lasers in hybrid systems based on coupling room‐temperature atomic gases with both dielectric and metallic nanophotonic systems is investigated. Two different classes of devices resulting from incorporating an optically pumped Rb–ethane mixture in a dielectric ring resonator and a plasmonic lattice are studied. It is shown that the combination of the optical gain provided by the atomic vapor, along with the unique field‐confinement properties of nanophotonic structures, enables the generation of coherent radiation, that is, laser light, at moderate power levels. In addition, general design guidelines for these hybrid nanophotonic lasers are provided. These results pave the way toward a novel class of active nanophotonic and metamaterial systems.
Borocyclopropanation of Styrenes Mediated by UV‐light Under Continuous Flow Conditions
Authors: Sayes Morgane , Benoit Guillaume , Charette André B. 
Published: September 2018

AbstractHerein, we report a user‐friendly and metal‐free UV‐A light mediated borocyclopropanation of styrenes using continuous flow technology. A broad range of styrene derivatives can be cyclopropanated in good yields within 1 h residence time to produce highly valuable cyclopropylboronate esters with modest to good diastereoselectivities. The reaction is also applicable to α‐substituted styrenes. Mechanistic studies support a photoredox process during which xanthone, a well‐known organic photosensitizer, can easily reach a photoexcited state that is available for both an oxidative and a reductive quenching.
Divergent Reactivity of Stannane and Silane in the Trifluoromethylation of PdII: Cyclic Transition State versus Difluorocarbene Release
Authors: Pu Maoping , Sanhueza Italo A. , Senol Erdem , Schoenebeck Franziska 
Published: September 2018

AbstractThe transmetalation is a key elementary step in cross‐coupling reactions. Yet, the precise nature of its mechanism and transition state geometry are frequently elusive. This report discloses our study of the transmetalation of [PdII]‐F complexes with the silane‐ and stannane‐based trifluoromethylation agents, R3SiCF3and R3SnCF3. A divergent reactivity was uncovered, with the stannane showing selective R‐group transfer, and the silane selective CF3‐group transfer. Using a combined experimental and computational approach, we uncovered a hitherto unrecognized transmetalation mechanism with the widely employed R3SiCF3reagent, explaining its unique activity in metal‐catalyzed trifluoromethylations. While the stannane reacts via a cyclic, 4‐membered transition state, the silane undergoes a fundamentally different pathway and releases a difluorocarbene in the transmetalation event. Molecular dynamics studies clearly reinforced the liberation of a free CF2carbene, which reacts with [PdII]‐F to ultimately generate [PdII]‐CF3.
Electrostatic Origins of Linear Scaling Relationships at Bifunctional Metal/Oxide Interfaces: A Case Study of Au Nanoparticles on Doped MgO Substrates
Authors: Choksi Tej , Majumdar Paulami , Greeley Jeffrey P. 
Published: September 2018

AbstractLinear scaling relationships (SRs), which relate binding energies of adsorbates across a space of catalyst surfaces, have been extensively explored for metal and oxide surfaces, but little is known about their properties at interfaces between metal nanoparticles and oxide supports, which are ubiquitous in heterogeneous catalysis. Using periodic DFT calculations, scaling principles are extended to bifunctional Au/oxide interfaces. Adopting a Au nanorod on doped MgO (100) as a model, SRs for species participating in water gas shift, methanol synthesis, and oxidation reactions are reported. SR slopes are not constrained by the bond order conservation rule postulated for metals, oxides, and zeolites, potentially permitting greater flexibility in catalyst design strategies. The deviation from bond counting, along with the physical origin of scaling behavior at interfaces, are explored using a conceptual framework involving electrostatic interactions at the Au/oxide interface.