bluuebunny/crossref_metadata_2025_split huggingface dataset:
Coupling of Photoinduced Mass Immigration with Polymer Networks to Produce Nanostructured Materials Capable of Reversibly Creating Arbitrary Deformations
Authors: Yin Xianpeng , Dong Hao , Wang Shiqiang , Liang Yun , Zhang Wanlin , Gao Ning , Liu Xiyang , Wang Xiaogong , Li Guangtao 
Published: June 2018

AbstractPhotoresponsive materials have tremendous potential applications in many fields. However, it is still a challenge to realize such materials, especially in isolated micro‐ or nanostructured form, with precisely controlled photomechanics for creating arbitrary deformations in a reversible way. Based on the coupling of photoinduced mass immigration with polymer networks, a general concept is proposed for producing nanostructured materials capable of reversibly creating arbitrary deformations. It is found for these type of materials the molecule alignment in the formation of a polymer network is not necessary to generate large anisotropic strain and stress. Importantly, the photoinduced mass immigration in a polymer network can provide unprecedented freedom in rapid exceptional spatiotemporal control over the molecule alignment profile and thus mechanical response within the network, enabling polymer formation of arbitrary deformations. Moreover, the inscribed molecule alignment profile is erasable and the fabricated materials can serve as a reconfigurable platform to present different mechanical behaviors.
Relationship between computer segmentation performance and computer classification performance in breast CT: A simulation study using RGI segmentation and LDA classification
Authors: Lee Juhun , Nishikawa Robert M. , Reiser Ingrid , Boone John M. 
Published: June 2018

PurposeMany computer aided diagnosis (CADx) tools for breast cancer begin by fully or semiautomatically segmenting a given breast lesion and then classifying the lesion's likelihood of malignancy using quantitative features extracted from the image. It is often assumed that better segmentation will result in better classification. However, this has not been thoroughly evaluated. The purpose of this study is to evaluate the relationship between computer segmentation performance and computer classification performance.MethodWe used 85 breast lesions (32 benign, 56 malignant) from breast computed tomography (CT) cases of 82 women. We prepared one smooth and one sharp iterative image reconstructions (IIR) and a clinical reconstruction for each of the 82 breast CT scans. For each reconstruction, we created 15 segmentation outcomes by applying 15 different segmentation algorithms. Specifically, we simulated 15 segmentation algorithms by changing parameters in a single segmentation algorithm. We then created 15 classification outcomes by conducting quantitative image feature analysis on the segmented image results. Using a 10‐fold cross‐validation, we evaluated the relationship between segmentation and classification performances.ResultWe found a low positive correlation between segmentation and classification performances for the smooth IIR (median Pearson's rho = 0.18), while a moderate positive correlation (median Pearson's rho = 0.4−0.43) was found between the two performances for the sharp IIR and clinical reconstruction. However, we found large variations in both segmentation and classification performances for the sharp IIR and clinical reconstruction. There were cases where segmentation algorithms resulted in similar segmentation performances, but the corresponding classification performances were different. These results indicate that an improvement in segmentation performance does not guarantee an improvement in the corresponding classification performance.ConclusionComputer segmentation is an indirect variable affecting the computer classification. As better segmentation does not guarantee better classification, we should report both segmentation and classification performances when comparing segmentation algorithms.
Modeling the connectivity and intersection of hydraulically loaded cracks with in situ fractures in rock
Authors: Clarke Philip L. , Abedi Reza 
Published: June 2018

SummaryThe interaction of an advancing hydraulically loaded crack and in situ fracture network can yield highly complex patterns. We model the connectivity of cells in a finite element domain and in a fracture network by a simplicial complex data structure. The complete adjacency information between cells is determined by one level down facet and one level up cofacet neighborhood information. Combined with a disjoint set data structure, explicit algorithms are derived to efficiently track network connectivity and load transfer between independent fracture sets. We also propose an approach to regularize the application of hydraulic load to newly intersected in situ cracks to smoothen the transition of pressure on intersected cracks from ambient to hydraulic pressure and to avoid the sudden loading of the entire length of these cracks. Numerical results demonstrate the performance of crack connectivity and load transfer models and the effect of regularization model. The results show that as the angle between an incoming hydraulically loaded crack and an in situ crack increases, the effect of in situ crack shifts from slight realignment to diversion/offsetting of the loaded crack. As the angle difference approaches the normal angle, the loaded crack tends to penetrate through the in situ crack. The proposed schemes are also used for transient simulation of 2D reservoirs with multiple perforations surrounded by in situ cracks with and without a bias in the distribution of their orientation. It was shown that from 2 perforations with angles closer to in situ cracks at low loading rates to all perforations at higher loading rates can result in active hydraulic crack propagation. The h‐adaptive method of asynchronous space‐time discontinuous Galerkin method is used to exactly track complex fracture patterns in these dynamic fracture simulations.
A micromechanics‐based inverse study for stochastic order reduction of elastic UD fiber reinforced composites analyses
Authors: Wu L. , Adam L. , Noels L. 
Published: June 2018

SummaryThis research develops a stochastic mean field homogenization process that is used as reduced order model to carry out a statistical multiscale analysis on unidirectional fiber reinforced composites. First, full‐field simulations of unidirectional stochastic volume elements, whose statistical description is obtained from scanning electron microscope images, are conducted to define statistical mesoscale apparent properties. A stochastic Mori‐Tanaka (M‐T) mean field homogenization model is then developed through an inverse stochastic identification process performed on the apparent elastic properties obtained by full‐field simulations. As a result, a random vector of the effective elastic properties of phases and microstructure information of the M‐T model is inferred. In order to conduct stochastic finite element method analyses, a generator of this random vector is then constructed using the copula method, allowing predicting the statistical response of a composite ply under bending. The statistical dependence of the random vector entries is shown to be respected by the generator. Although this work is limited to the elastic response, we believe that the stochastic M‐T model can be extended to nonlinear behaviors to conduct efficient stochastic multiscale simulations.
Modified whale optimization algorithm for fractional‐order multi‐input SSSC‐based controller design
Authors: Sahu Preeti Ranjan , Hota Prakash Kumar , Panda Sidhartha 
Published: June 2018

SummaryIn this paper, the design of a fractional‐order (FO) multi‐input–single‐output (MISO)–type static synchronous series compensator (SSSC) is proposed with a goal to improve the power system stability using modified whale optimization algorithm (MWOA). The proposed MWOA achieves an appropriate balance between exploitation and exploration stages of the original whale optimization algorithm. The performance of MWOA is validated by employing the benchmark test functions and further contrasted with whale optimization algorithm and other heuristic algorithms like gravitational search algorithm, particle swarm optimization, differential evolution, and fast evolutionary programming algorithms to demonstrate its strength. The proposed FO MISO SSSC controller is optimized by the MWOA technique and tested under single‐machine infinite bus system and further extended to a multi‐machine framework. To demonstrate the superiority of MISO‐type SSSC controller, the results obtained from it are compared with particle swarm optimization and differential evolution–based conventional single‐input–single‐output structured SSSC controllers. The comparison of results of MWOA with that of other methods validates its superiority in the present context.
Assessing the possible association of anti‐TNF use with new malignancies: A neglected methodological consideration
Authors: Ozguler Yesim , Yazici Yusuf , Hatemi Gulen , Tascilar Koray , Yazici Hasan 
Published: June 2018

AbstractPurposeWhether anti‐TNF agents increase, malignancy risk remains debated. The potential problems with comparing the number of observed malignancies in anti‐TNF treated cohorts to number of expected malignancies in national cancer registries could have been an important issue. National registries give expected number of malignancies per organ involved regardless of if this is a secondary or a higher malignancy while anti‐TNF agents are not or are sparingly used in patients with an existing or history of a malignancy. This results in a biased standardized incidence ratio (SIR). We aimed to formally look at the presence and the magnitude of this bias in published work.MethodsA systematic search was performed in PUBMED/MEDLINE about anti‐TNF use in rheumatoid arthritis (RA) up to July 2016. The main outcome sought was malignancy incidence in a RA cohort as compared with that in the general population. Randomized controlled trials, meta‐analyses, and articles published in languages other than English were excluded.ResultsThe potentially biased SIR was discussed in only 1 of 29 studies we analyzed, while in none of these studies, the authors highlighted this as a limitation. We were able to approximate the pooled SIR for overall malignancy in 12 studies before and after correcting for this bias. It was 0.89 (CI: 0.84‐0.95) before and increased to 1.05 (CI: 0.99‐1.11), when corrected.ConclusionPlanning and assessment of studies investigating malignancy incidence possibly related to anti‐TNF use in RA, and probably in other diseases, should take into consideration the described bias in SIR calculations.
Relationship between International Normalized Ratio and Outcomes in Modern Trials with Warfarin Controls
Authors: McDowell Tzu‐Yun , Lawrence John , Florian Jeffry , Southworth Mary Ross , Grant Stephen , Stockbridge Norman 
Published: June 2018

IntroductionA target international normalized ratio (INR) of 2–3 has been recommended for patients with atrial fibrillation (AF) and risk factors for thromboembolism. This recommendation is largely based on evidence from observational studies a decade ago. This study utilized collective data from modern trials with warfarin controls to examine the relationship of warfarin anticoagulation, as assessed by INR, on the clinical outcome events of interest.MethodsData on warfarin‐treated patients from three clinical studies supporting the approval of dabigatran (Pradaxa), apixaban (Eliquis), and edoxaban (Savaysa) were pooled. Ischemic stroke, intracranial hemorrhage (ICH), and all‐cause death were selected as the outcome events of interest. Multivariate Cox regression modeling was performed to examine the association between time‐dependent INR and each outcome event. Benefit‐risk assessment was evaluated by summing the estimated annual event rate for ischemic stroke and ICH.ResultsA total of 21,883 patients representing 322 ischemic strokes, 288 ICHs, and 657 all‐cause deaths were included in the analysis. The models used suggest that the risk of ischemic stroke is greatly reduced when INR exceeds 2; in contrast, the risk of ICH increases monotonically as INR increases. When combining ischemic stroke and ICH events, the lowest estimated annual event rate was observed between INR of 2 and 2.5; the risk only slightly increased between INR of 1.8 and 3.0. Similarly, a U‐shaped relationship between INR and the risk of all‐cause death was found.ConclusionsThis study using collective warfarin data from recent large prospective trials indicates that INR between 2 and 2.5 provides the best balance between ischemic stroke and ICH, as well as optimal protection against death in patients with AF.
Insights into the optical, magnetic and dielectric properties of some novel polysulfone/NiFe2O4 composite materials
Authors: Pascariu Petronela , Airinei Anton , Asandulesa Mihai , Rotaru Aurelian 
Published: June 2018

AbstractNovel polysulfone (PSU)/NiFe2O4 nanocomposites with good magneto‐dielectric properties were prepared in a simple and cost‐effective manner. Nickel ferrite nanoparticles exhibit a cubic spinel phase without any impurity phases according to X‐ray diffraction characterization. Transmission electron microscopy images of the nanoparticles showed a tetragonal particle shape with average particle size of 17–30 nm. The thermal stability of PSU proved to remain unaffected by nanoparticle concentration in the composite material. The emission spectra of the PSU/NiFe2O4 nanocomposites present a broad emission band located at 370 nm due to free exciton recombination. The composites exhibit hysteresis loops of a ferrimagnetic nature and good dielectric properties. Coercivity value measured at room temperature is 20.64 and 24.98 Oe and the squareness (Mr/Ms) is 0.290 and 0.225 for both polymer composite samples (4 and 24 vol% Ni ferrite). The formalism of the dielectric loss has been used to estimate the dipolar relaxations expressed by γ‐ and β‐relaxation processes. The presence of Ni ferrite nanoparticles in the PSU matrix increases the activation energy of secondary relaxations, which means a reduction of the molecular mobility in the nanocomposites as compared to PSU. © 2018 Society of Chemical Industry
Hydroxide degradation pathways for guanidimidazolium cation: A density functional theory study
Authors: Li Guang‐Lan , Yang Guoqing , Cheng Jie , Zhang Fengxiang , Hao Ce 
Published: June 2018

AbstractThe chemical stability of anion exchange membrane especially in strong alkaline medium under high temperature is one of the crucial challenges for the commercialization of alkaline anion exchange membrane fuel cells. Herein, the degradation mechanism of guanidimidazolium ionic group used in anion exchange membrane was calculated by density functional theory method. The whole transition states of every elemental reaction were systematically searched, and the changes of crucial bonds length were further analyzed for understanding of the reaction mechanism. It was found that the reaction pathway of OH− attacking guanidinium group of guanidimidazolium was the dominant way for the degradation of guanidimidazolium. Through comparing the energy barriers of guanidimidazolium, imidazolium, and guanidinium, it can be concluded that the electron‐inducing effect had an intimate connection with the alkali stability of ionic groups. The chemical stability of the conjugated structure groups decreased when linking with electron‐drawing groups, while it increased when linking with electron‐donating groups. This work provides theoretical basis for the design of decent alkali‐resistance and high‐performance anion exchange membrane.
Ordered Networks of Gold Nanoparticles Crosslinked by Dithiol‐Oligomers
Authors: Nayak Srikanth , Horst Nathan , Zhang Honghu , Wang Wenjie , Mallapragada Surya , Travesset Alex , Vaknin David 
Published: June 2018

AbstractControlled aggregation of nanoparticles into superlattices is a grand challenge in material science, where ligand based self‐assembly is the dominant route. Here, the self‐assembly of gold nanoparticles (AuNPs) that are crosslinked by water soluble oligo‐(ethylene glycol)‐dithiol (oEG‐dithiol) is reported and their 3D structure by small angle X‐ray scattering is determined. Surprisingly, a narrow region is found in the parameter space of dithiol linker‐length and nanoparticle size for which the crosslinked networks form short‐ranged FCC crystals. Using geometrical considerations and numerical simulations, the stability of the formed lattices is evaluated as a function of dithiol length and the number of connected nearest‐neighbors, and a phase diagram of superlattice formation is provided. Identifying the narrow parameter space that allows crystallization facilitates focused exploration of linker chemical composition and medium conditions such as thermal annealing, pH, and added solutes that may lead to superior and more robust crystals.
Advances in the Synthesis and Long‐Term Protection of Zero‐Valent Iron Nanoparticles
Authors: Mehta Joshua P. , Knappett Benjamin R. , Divitini Giorgio , Ringe Emilie , Midgley Paul A. , Fairen‐Jimenez David , Wheatley Andrew E. H. 
Published: June 2018

AbstractCore@shell Fe@Fe3O4 nanoparticles (NPs) are synthesized via the thermal decomposition of iron pentacarbonyl (Fe(CO)5) in the presence either of oleylamine (OAm) or a mixture of OAm and oleic acid (OA). The heterostructured nanocomposites formed do so by a postsynthetic modification of isolated Fe seeds. This proves the versatility of the coating procedure and represents a significant advantage over previous work with Co seeds owing to the higher magnetic susceptibility, reduced toxicity, and excellent biocompatibility of Fe. Furthermore, the latter system allows the synthetic methodology to be developed from a two‐pot scenario where seeds are isolated then coated, to an easier and more efficient direct one‐pot scenario. The two‐pot method yields proportionately larger cores. However, in both cases, the monodisperse product reveals a carbonaceous interface between the Fe core and oxide shell. Meanwhile for the one‐pot synthesis, the OA:OAm ratio influences both the morphology and dispersity of the product. This is interpreted in terms of competing interactions of the ligands with the iron precursor. Superparamagnetism (SPM) is observed, and microscopic studies reveal oxidative stability of the Fe(0) cores achieved by either method for >6 months. It is proposed that the carbonaceous interface is critical to this sustained oxidative stability.
Improving Dielectric Nanoresonator Array Coatings for Solar Cells
Authors: Ha Dongheon , Zhitenev Nikolai B. 
Published: June 2018

AbstractAntireflection coatings based on dielectric nanosphere arrays are discussed in application to photovoltaic materials including silicon and gallium arsenide. Macro‐ and nanoscale characterizations and finite‐difference time‐domain calculations are performed, and demonstrate the enhanced optoelectronic properties. A significant absorptivity enhancement is achieved due to the collective resonant coupling of excited whispering gallery‐like modes and thin‐film interference effects. The resonant coupling is masked in macroscale measurements by the size variation of nanospheres, but it is clearly seen through imaging photocurrent at the nanoscale with near‐field scanning photocurrent microscopy. The resonant coupling can be effectively tuned by the material, configuration, or size of nanospheres. Hybrid coatings combining nanospheres of different materials yield the highest efficiency gain of more than 30%. The impact of manufacturing defects, such as double layer formation, is also evaluated. While the performance degrades, the antireflection coating still offers marked improvement in comparison with bare cells.
A Nano‐Micro Hybrid Structure Composed of Fe7S8 Nanoparticles Embedded in Nitrogen‐Doped Porous Carbon Framework for High‐Performance Lithium/Sodium‐Ion Batteries
Authors: Liu Zhiming , Hu Fang , Xiang Juan , Yue Chuang , Lee Dongsoo , Song Taeseup 
Published: June 2018

AbstractIron sulfides are attractive anode materials for lithium‐ion batteries (LIBs) and sodium‐ion batteries (SIBs) due to their high theoretical capacities, low cost, and eco‐friendliness. However, their real application is greatly hindered by the rapid capacity fading caused by the large volume changes and sluggish kinetics of iron sulfides during the charge and discharge processes. Combining with carbonaceous materials and tuning the structure at nanoscale are essential to address this issue. Here, a facile hydrothermal method coupled with a carbonization process is developed to synthesize a nano‐micro hybrid porous structure, which is composed of Fe7S8 nanoparticles embedded in nitrogen‐doped carbon framework (Fe7S8@NC‐PS). This hierarchical sphere is constructed by interconnected 2D nanowalls. The as‐prepared Fe7S8@NC‐PS electrodes reveal excellent rate capability and cycling stability in LIBs and SIBs. The remarkable electrochemical properties are attributed to the porous nano‐micro hybrid architecture and the high conductivity and structural stability of the nitrogen‐doped carbon framework.
Linking the family context of migration during childhood to the well‐being of young adults: Evidence from the UK and France
Authors: Eremenko Tatiana , Bennett Rachel 
Published: June 2018

AbstractFamilies often undergo separations during the migration process. A body of literature has explored the consequences of these separations for children “left behind” and, more recently, children reunified with their parents at the destination. However, little attention has been given to whether this experience during childhood is associated with well‐being into adulthood. This paper adopts a life course perspective to explore well‐being amongst youth (18–25 years) who migrated as children to the UK and France. Drawing on national household surveys, Understanding Society (UK) and Trajectories and Origins (France), we analyse whether which of the parents migrated and whether the young person migrated with them or experienced a period of separation are associated with self‐rated health (both countries) and mental well‐being (UK) or conflict with parents (France). Our findings show that whilst the majority of youth migrated with their parents (86% in the UK and 69% in France), those who did experience long‐term parental separation (6+ years) have poorer psychosocial well‐being in both destinations. This suggests that disruption to the parent–child relationship amplifies the risk of poorer outcomes in early adulthood and highlights that the context of family migration is not only important for understanding migrants' well‐being during childhood, but also as they progress into adulthood.