bluuebunny/crossref_metadata_2025_split huggingface dataset:
A study on fluoroscopic images in exposure reduction techniques ― Focusing on the image quality of fluoroscopic images and exposure images
Authors: Sato Hisaya , Kittaka Daisuke , Ohsawa Miwa , Kato Kyoichi 
Published: April 2019

AbstractThe quality of the present day fluoroscopic images is sufficiently high for use as exposure images depending on the environment where the fluoroscopic images are recorded. In some facilities which use fluoroscopic images as exposure images they are recorded with a radiological x‐ray diagnostic device equipped with a fluoroscopic storage function. There are, however, cases where fluoroscopic images cannot be used as exposure images because the quality of the fluoroscopic image cannot be assured in the environment where the fluoroscopic images are recorded. This poses problems when stored fluoroscopic images are used in place of exposure images without any clearly established standard. In the present study, we establish that stored fluoroscopic images can be used as exposure images by using gray values obtained from profile curves. This study finds that replacement of stored fluoroscopic images with exposure images requires 20.1 or higher gray scale value differences between the background and signal, using a 20 cm thick acrylic phantom (here an adult abdomen as representing the human body) as the specific geometry. This suggests the conclusion that the gray value can be considered a useful index when using stored fluoroscopic images as exposure images.
Templated Self‐Replication in Biomimetic Systems
Authors: Le Vay Kristian , Weise Laura Isabel , Libicher Kai , Mascarenhas Judita , Mutschler Hannes 
Published: April 2019

AbstractA key characteristic of living systems is the storage and replication of information, and as such the development of self‐replicating systems capable of heredity is of great importance to the fields of synthetic biology and origin of life research. In this review, the design and implementation of self‐replicating systems in the context of bottom‐up synthetic biology is discussed, with a particular focus on nucleic acid‐based replication including nonenzymatic systems, ribozyme‐based systems, and complex in vitro translation coupled RNA and DNA replication. The current state and remaining challenges of the respective fields are discussed, and the potential of individual replicators for synthetic biology applications such as the creation of artificial life capable of Darwinian evolution is also summarized.
Efficient Ruddlesden–Popper Perovskite Light‐Emitting Diodes with Randomly Oriented Nanocrystals
Authors: Lee Hyeon‐Dong , Kim Hobeom , Cho Himchan , Cha Wonhee , Hong Yongseok , Kim Young‐Hoon , Sadhanala Aditya , Venugopalan Vijay , Kim Joo Sung , Choi Jin Woo , Lee Chang‐Lyoul , Kim Dongho , Yang Hoichang , Friend Richard H. , Lee Tae‐Woo 
Published: April 2019

AbstractRuddlesden–Popper phase (RP‐phase) perovskites that consist of 2D perovskite slabs interleaved with bulky organic ammonium (OA) are favorable for light‐emitting diodes (LEDs). The critical limitation of LED applications is that the insulating OA arranged in a preferred orientation limits charge transport. Therefore, the ideal solution is to achieve a randomly connected structure that can improve charge transport without hampering the confinement of the electron–hole pair. Here, a structurally modulated RP‐phase metal halide perovskite (MHP), (PEA)2(CH3NH3)m−1PbmBr3m+1 is introduced to make the randomly oriented RP‐phase unit and ensure good connection between them by applying modified nanocrystal pinning, which leads to an increase in the efficiency of perovskite LEDs (PeLEDs). The randomly connected RP‐phase MHP forces contact between inorganic layers and thereby yields efficient charge transport and radiative recombination. Combined with an optimal dimensionality, (PEA)2(CH3NH3)2Pb3Br10, the structurally modulated RP‐phase MHP exhibits increased photoluminescence quantum efficiency, from 0.35% to 30.3%, and their PeLEDs show a 2,018 times higher current efficiency (20.18 cd A−1) than in the 2D PeLED (0.01 cd A−1) and 673 times than in the 3D PeLED (0.03 cd A−1) using the same film formation process. This approach provides insight on how to solve the limitation of RP‐phase MHP for efficient PeLEDs.
Ultrathin Molybdenum Carbide MXene with Fast Biodegradability for Highly Efficient Theory‐Oriented Photonic Tumor Hyperthermia
Authors: Feng Wei , Wang Rongyan , Zhou Yadan , Ding Li , Gao Xiang , Zhou Bangguo , Hu Ping , Chen Yu 
Published: April 2019

AbstractThe explosion of emerging high‐performance 2D MXenes in theranostic nanomedicine is still at the preliminary stage. Despite tremendous efforts devoted to photonic tumor hyperthermia, current photothermal‐conversion nanoagents still suffer from critical issues preventing further clinical translation such as low biodegradability. Here, for the first time, the construction of novel 2D molybdenum carbide (Mo2C) MXenes for photonic tumor hyperthermia is reported. The structure of both bulk Mo2Ga2C ceramic and Mo2C MXene is fully revealed. Especially, computational simulation, as a novel strategy and a powerful tool for photonic‐performance prediction, is employed to reveal that Mo2C MXene is featured with intense near‐infrared (NIR) absorption, covering the first and the second biological transparency window (NIR I and II). After further surface engineering with polyvinyl alcohol (PVA), Mo2C‐PVA nanoflakes exhibit high biocompatibility and fast degradability. Importantly, it is experimentally corroborated that Mo2C‐PVA nanoflakes possess intriguing broad absorption band spanning NIR in both the I and II regions, and desirable photothermal‐conversion efficiency (24.5% for NIR I and 43.3% for NIR II). This study not only broadens the nanomedical applications of MXene by fabricating novel material members (Mo2C), but also provides the paradigm of inorganic multifunctional biomedical nanoplatform with desirable biodegradability and high therapeutic performance.
Self‐Supported Transition‐Metal‐Based Electrocatalysts for Hydrogen and Oxygen Evolution
Authors: Sun Hongming , Yan Zhenhua , Liu Fangming , Xu Wence , Cheng Fangyi , Chen Jun 
Published: April 2019

AbstractElectrochemical water splitting is a promising technology for sustainable conversion, storage, and transport of hydrogen energy. Searching for earth‐abundant hydrogen/oxygen evolution reaction (HER/OER) electrocatalysts with high activity and durability to replace noble‐metal‐based catalysts plays paramount importance in the scalable application of water electrolysis. A freestanding electrode architecture is highly attractive as compared to the conventional coated powdery form because of enhanced kinetics and stability. Herein, recent progress in developing transition‐metal‐based HER/OER electrocatalytic materials is reviewed with selected examples of chalcogenides, phosphides, carbides, nitrides, alloys, phosphates, oxides, hydroxides, and oxyhydroxides. Focusing on self‐supported electrodes, the latest advances in their structural design, controllable synthesis, mechanistic understanding, and strategies for performance enhancement are presented. Remaining challenges and future perspectives for the further development of self‐supported electrocatalysts are also discussed.
Coated and Printed Perovskites for Photovoltaic Applications
Authors: Howard Ian A. , Abzieher Tobias , Hossain Ihteaz M. , Eggers Helge , Schackmar Fabian , Ternes Simon , Richards Bryce S. , Lemmer Uli , Paetzold Ulrich W. 
Published: April 2019

AbstractHybrid organic–inorganic metal halide perovskite semiconductors provide opportunities and challenges for the fabrication of low‐cost thin‐film photovoltaic devices. The opportunities are clear: the power conversion efficiency (PCE) of small‐area perovskite photovoltaics has surpassed many established thin‐film technologies. However, the large‐scale solution‐based deposition of perovskite layers introduces challenges. To form perovskite layers, precursor solutions are coated or printed and these must then be crystallized into the perovskite structure. The nucleation and crystal growth must be controlled during film formation and subsequent treatments in order to obtain high‐quality, pin‐hole‐free films over large areas. A great deal of understanding regarding material engineering during the perovskite film formation process has been gained through spin‐coating studies. Based on this, significant progress has been made on transferring material engineering strategies to processes capable of scale‐up, such as blade coating, spray coating, inkjet printing, screen printing, relief printing, and gravure printing. Here, an overview is provided of the strategies that led to devices deposited by these scalable techniques with PCEs as high as 21%. Finally, the opportunities to fully close the shrinking gap to record spin‐coated solar cells and to scale these efficiencies to large areas are highlighted.
Substitution Conformation Balances the Oscillator Strength and Singlet–Triplet Energy Gap for Highly Efficient D–A–D Thermally Activated Delayed Fluorescence Emitters
Authors: Wei Xiaofang , Li Zhiyi , Hu Taiping , Duan Ruihong , Liu Jianjun , Wang Ruifang , Liu Yanwei , Hu Xiaoxiao , Yi Yuanping , Wang Pengfei , Wang Ying 
Published: April 2019

AbstractFour donor–acceptor–donor region isomers (2,3‐TXO‐PhCz, 2,6‐TXO‐PhCz, 2,7‐TXO‐PhCz, and 3,6‐TXO‐PhCz) are designed. The substitution positions of the two PhCz units significantly impact the photophysical properties of the isomers, especially for the singlet–triplet energy splitting (ΔEST) and oscillator strength (f ). 2,3‐TXO‐PhCz exhibits weak emission due to the large steric hindrance of the two PhCz units. While 2,6‐TXO‐PhCz, 2,7‐TXO‐PhCz, and 3,6‐TXO‐PhCz all exhibit strong emission. The four emitters possess small ΔEST of 0.01–0.24 eV; the corresponding f values are 0.064, 0.107, 0.026, and 0.134. Consequently, the photoluminescence quantum yields (PLQYs) of the doped films in CBP host are: 62.1% for 2,3‐TXO‐PhCz, 83.8% for 2,6‐TXO‐PhCz, 89.0% for 2,7‐TXO‐PhCz, and 85.4% for 3,6‐TXO‐PhCz. Although notable divergences of f and ΔEST exist between 2,6‐TXO‐PhCz and 2,7‐TXO‐PhCz, similar PLQY of doped film in the CBP host, and exciton utilization and external quantum efficiency (EQE) of the corresponding devices can be achieved: 2,6‐TXO‐PhCz and 2,7‐TXO‐PhCz endow the organic light‐emitting devices with high EQE of 23.2% and 24.4%. This proximity can be attributed to the synergistic effect of f and ΔEST. This finding highlights the beneficial role of the different linking positions on the acceptor unit in facilitating the adjustment of f and ΔEST in order to improve the device efficiency.
Nickel‐Catalyzed Construction of 2,4‐Disubstituted Imidazoles via C–C Coupling and C−N Condensation Cascade Reactions
Authors: Fang Shengyang , Yu Haihua , Yang Xicheng , Li Jianqi , Shao Liming 
Published: April 2019

AbstractA convenient Ni(II)‐catalyzed C−C and C−N cascade coupling reaction was developed to directly access various 2,4‐disubstituted imidazoles. The reaction scope covers a variety of aryl and aliphatic substitutions, which demonstrate moderate‐to‐excellent yields. The tolerance of halogen and N‐containing heterocyclic groups demonstrates the versatility of this method for further synthetic explorations.magnified image
Room‐Temperature Ferromagnetism in MoTe2 by Post‐Growth Incorporation of Vanadium Impurities
Authors: Coelho Paula Mariel , Komsa Hannu‐Pekka , Lasek Kinga , Kalappattil Vijaysankar , Karthikeyan Jeyakumar , Phan Manh‐Huong , Krasheninnikov Arkady V. , Batzill Matthias 
Published: April 2019

AbstractPost‐synthesis doping of 2D materials is demonstrated by incorporation of vapor‐deposited transition metals into a MoTe2 lattice. Using this approach, vanadium doping of 2H‐MoTe2 produces a 2D ferromagnetic semiconductor with a Curie temperature above room temperature (RT). Surprisingly, ferromagnetic properties can be induced with very low vanadium concentrations, down to ≈0.2%. The vanadium species introduced at RT are metastable, and annealing to above ≈500 K results in the formation of a thermodynamically favored impurity configuration that, however, exhibits reduced ferromagnetic properties. Doping with titanium, instead of vanadium, shows a similar incorporation behavior, but no ferromagnetism is induced in MoTe2. This indicates that the type of impurities in addition to their atomic configuration is responsible for the induced magnetism. The interpretation of the experimental results is consistent with ab initio calculations, which confirm that the proposed vanadium impurity configurations exhibit magnetic moments, in contrast to the same configurations with titanium impurities. This study illustrates the possibility to induce ferromagnetic properties in layered van der Waals semiconductors by controlled magnetic impurity doping and thus to add magnetic functionalities to 2D materials.
The Dominant Energy Transport Pathway in Halide Perovskites: Photon Recycling or Carrier Diffusion?
Authors: Gan Zhixing , Wen Xiaoming , Chen Weijian , Zhou Chunhua , Yang Shuang , Cao Guiyuan , Ghiggino Kenneth P. , Zhang Hua , Jia Baohua 
Published: April 2019

AbstractPhoton recycling and carrier diffusion are the two plausible processes that primarily affect the carrier dynamics in halide perovskites, and therefore the evaluation of the performance of their photovoltaic and photonic devices. However, it is still challenging to isolate their individual contributions because both processes result in a similar emission redshift. Herein, it is confirmed that photon recycling is the dominant effect responsible for the observed redshifted emission. By applying one‐ and two‐photon confocal emission microscopy on Ruddlesden–Popper type 2D perovskites, of which interplane carrier diffusion is strictly suppressed, the substantial PL redshift (72 meV) is well reproduced by the photon transport model. A comparison of 3D bulk CH3NH3PbBr3 single crystal to 2D perovskite by depth‐resolved two‐photon PL spectra reveals the contribution of carrier diffusion on energy transport at a distance beyond diffusion length is constantly negligible, though the carrier diffusion indeed exists in the 3D crystal. The investigation resolves the fundamental confusion and debate surrounding the issue and provides significant insights into carrier kinetics in perovskites, which is important for future developments in solar cells and other optoelectronic devices.
Rapid changes in eastern Himalayan alpine flora with climate change
Authors: Salick Jan , Fang Zhendong , Hart Robbie 
Published: April 2019

Premise of the StudyWith biodiversity and rates of climate change among the highest, the eastern Himalaya are critical for understanding the interaction of these two variables. However, there is a dearth of longitudinal data sets that address the effects of climate change on the exceptional alpine biodiversity of the Himalaya.MethodsWe established permanent alpine vegetation monitoring plots in three mountain chains of the Hengduan Mountains, the easternmost Himalaya, which have warmed 0.03–0.05°C yr−1since 1985. Recently, we resampled plots (176 1‐m2quadrat plots and 88 sections of 11 summits in three Hengduan mountain chains) to measure changes in vegetation after 7 years.Key ResultsOver 7 years, Tibetan alpine vegetation increased in number of species (+8 species/summit; +2.3 species/m2), in frequency (+47.8 plants/m2), and in diversity (+1.6 effective species/m2). Stepwise regressions indicated that warmer temperatures, southerly aspects, and higher elevations were associated with greater increases in these vegetation metrics. Unexpectedly, Himalayan endemic species increased (+1.4 species/m2; +8.5 plants/m2), especially on higher‐elevation summits. In contrast, the increase in relative abundance of non‐alpine species was greater at lower‐elevation summits. Plants used by local Tibetans also increased (+1.3 species/m2; +32 plants/m2).ConclusionsAs in other alpine areas, biodiversity is increasing with climate change in the Himalaya. Unlike other areas, endemic species are proliferating at the highest summits and are indicators of change.
Interactions of plant growth responses to spring freezing and summer drought: a multispecies comparison
Authors: Kong Ricky S. , Henry Hugh A. L. 
Published: April 2019

Premise of the StudyFreezing and drought both result in cellular dehydration, and similar physiological responses to these stressors may result in cross acclimation, whereby prior freezing exposure increases subsequent drought tolerance. We examined how spring freezing influences summer drought tolerance for a range of herbaceous old field species: 6 graminoids (Agrostis stolonifera, Arrhenatherum elatius, Bromus inermis, Festuca rubra, Lolium perenne, Poa compressa) and 2 forbs (Plantago lanceolata, Securigera varia), with the goal of examining the generality of cross acclimation responses.MethodsWe exposed the plants to –5°C in the spring and to a 3‐week summer drought, and harvested the plants after a 3‐week watering/recovery period. We also measured leaf soluble proteins and sugars to explore the potential mechanisms before and during drought stress.Key ResultsFor Agrostis stolonifera, Bromus inermis, Lolium perenne, Plantago lanceolata, and Poa compressa there was evidence of cross acclimation based on aboveground or belowground biomass, with a reduction in the severity of the drought effect for the plants previously exposed to freezing. Freezing and drought effects were additive for Arrhenatherum elatius, and for the remaining two species the test of the freezing‐drought interaction was inconclusive, because significant drought and freezing effects did not co‐occur. When present, freezing‐drought interactions were not correlated with changes in leaf soluble protein or sugars.ConclusionsOur results reveal that the phenomenon of freezing‐drought cross acclimation appears to be common in herbaceous species, and variation among species in cross acclimation indicates that multiple stresses could alter relative species abundances in plant communities.
Rapid Assessment of the Reaction‐Condition‐Based Sensitivity of Chemical Transformations
Authors: Pitzer Lena , Schäfers Felix , Glorius Frank 
Published: April 2019

AbstractA systematic, user‐friendly assessment tool that delivers a clear overview of the sensitivity of reactions to key parameters is highly desirable. Herein, the development of such a method is described. The intuitive, standardized presentation of the results in a radar diagram enables the sensitivity of a protocol to be rapidly assessed. This method was applied to five different visible‐light‐mediated photochemical reactions, and the results were correlated to the underlying mechanism. Ultimately, we believe that this assessment will help to increase the uptake of new synthetic methods and their reproducibility.
Malondialdehyde–Acetaldehyde Adducts and Antibody Responses in Rheumatoid Arthritis–Associated Interstitial Lung Disease
Authors: England Bryant R. , Duryee Michael J. , Roul Punyasha , Mahajan Tina D. , Singh Namrata , Poole Jill A. , Ascherman Dana P. , Caplan Liron , Demoruelle M. Kristen , Deane Kevin D. , Klassen Lynell W. , Thiele Geoffrey M. , Mikuls Ted R. 
Published: April 2019

ObjectiveTo compare serum anti–malondialdehyde–acetaldehyde (anti‐MAA) antibody levels and MAA expression in lung tissue from patients with rheumatoid arthritis–associated interstitial lung disease (RA‐ILD) to those found in controls.MethodsAnti‐MAA antibody (IgA, IgM, IgG) concentrations were measured in patients with RA‐ILD and compared to those of RA patients with chronic obstructive pulmonary disease (COPD) and RA patients without lung disease. Associations between anti‐MAA antibody with RA‐ILD were assessed using multivariable logistic regression. Lung tissue from patients with RA‐ILD, other ILD, or emphysema, and from controls (n = 3 per group) were stained for MAA, citrulline, macrophages (CD68), T cells (CD3), B cells (CD19/CD27), and extracellular matrix proteins (type II collagen, fibronectin, vimentin). Tissue expression and colocalization with MAA were quantified and compared.ResultsAmong 1,823 RA patients, 90 had prevalent RA‐ILD. Serum IgA and IgM anti‐MAA antibody concentrations were higher in RA‐ILD than in RA with COPD or RA alone (P = 0.005). After adjustment for covariates, the highest quartiles of IgA anti‐MAA antibody concentration (odds ratio 2.09 [95% confidence interval 1.11–3.90]) and IgM (odds ratio 2.23 [95% confidence interval 1.19–4.15]) were significantly associated with the presence of RA‐ILD. MAA expression in RA‐ILD lung tissue was greater than in tissue from all other groups (P < 0.001), and it colocalized with citrulline (r = 0.79), CD19+ B cells (r = 0.78), and extracellular matrix proteins (type II collagen [r = 0.72] and vimentin [r = 0.77]) to the greatest degree in RA‐ILD.ConclusionSerum IgA and IgM anti‐MAA antibody is associated with ILD among RA patients. MAA is highly expressed in RA‐ILD lung tissue, where it colocalizes with other RA autoantigens, autoreactive B cells, and extracellular matrix proteins, highlighting its potential role in the pathogenesis of RA‐ILD.
1,3‐O‐Transposition or Trisubstituted Z‐Enol Ester? A Comparative Study of Reactions of Ynones
Authors: Sun Tian‐Yu , Chen Kai , Zhang Changyuan , You Tingting , Yin Penggang 
Published: April 2019

AbstractYnones are useful substrates for transition‐metal‐mediated synthesis. The AuI‐catalyzed 1,3‐O‐transposition is an important reaction of ynones. Recently, an efficient CuI‐catalyzed synthesis of trisubstituted Z‐enol esters via interrupting the traditional 1,3‐O‐transposition reaction of ynones was reported by Zhu's group. Herein, density functional theory studies disclosed that the hydrogen bond formed by carboxylic acid plays an important role for the reactivity and selectivity in this novel reaction. A qualitative rule was also found to explain the substituent effect in the ynone substrate, and this is consistent with experiments. The AuI‐catalyst and CuI‐catalyst were further compared to interpret the essential cause of why the AuI‐catalyst prefers the 1,3‐O‐transpostion reaction. These conclusions might be helpful for the rational design of reactions of ynones.
Nonlinear modeling of PEMFC based on fractional order subspace identification
Authors: Qi Zhidong , Sun Qi , Ge Weiping , He Yongkang 
Published: April 2019

AbstractAiming at the multivariable, nonlinear and fractional‐order characteristics of proton exchange membrane fuel cell (PEMFC), this paper presents a nonlinear state space model based on a novel fractional Hammerstein model subspace identification theory. To reduce the complexity of modeling and choose the suitable input variables, canonical correlation analysis (CCA) method is used to select the most influential factors as the model input variables, and correlation analysis (CA) method is employed to remove the redundant input variables. To guarantee that the input‐output data are derivable at different fractional order, a Poisson moment function (PMF) is employed to construct the fractional order Hammerstein model with a six‐order polynomial as the front static nonlinear unit. To improve computing speed, a fractional differential short memory method (SMM) is proposed to reduce the computation cost of the identification algorithm. Meanwhile, a fuzzy genetic algorithm is adopted to acquire the best fractional order. Simulation results show that the fractional subspace identifying method can avoid fuel cell's internal complexity and PEMFC identification model can describe the working process of PEMFC accurately and quickly, which will provide an ideal control model for some advanced controller.