bluuebunny/crossref_metadata_2025_split huggingface dataset:
The Initial Development of Transient Volcanic Plumes as a Function of Source Conditions
Authors: Tournigand Pierre‐Yves , Taddeucci Jacopo , Gaudin Damien , Peña Fernández Juan José , Del Bello Elisabetta , Scarlato Piergiorgio , Kueppers Ulrich , Sesterhenn Jörn , Yokoo Akihiko 
Published: November 2017

AbstractTransient volcanic plumes, having similar eruption duration and rise timescales, characterize many unsteady Strombolian to Vulcanian eruptions. Despite being more common, such plumes are less studied than their steady state counterpart from stronger eruptions. Here we investigate the initial dynamics of transient volcanic plumes using high‐speed (visible light and thermal) and high‐resolution (visible light) videos from Strombolian to Vulcanian eruptions of Stromboli (Italy), Fuego (Guatemala), and Sakurajima (Japan) volcanoes. Physical parameterization of the plumes has been performed by defining their front velocity, velocity field, volume, and apparent surface temperature. We also characterized the ejection of the gas‐pyroclast mixture at the vent, in terms of number, location, duration, and frequency of individual ejection pulses and of time‐resolved mass eruption rate of the ejecta's ash fraction. Front velocity evolves along two distinct trends related to the initial gas‐thrust phase and later buoyant phase. Plumes' velocity field, obtained via optical flow analysis, highlights different features, including initial jets and the formation and/or merging of ring vortexes at different scales. Plume volume increases over time following a power law trend common to all volcanoes and affected by discharge history at the vent. Time‐resolved ash eruption rates range between 102 and 107 kg/s and may vary up to 2 orders of magnitude within the first seconds of eruption. Our results help detailing how the number, location, angle, duration, velocity, and time interval between ejection pulses at the vents crucially control the initial (first tens of second), and possibly later, evolution of transient volcanic plumes.
GPM Satellite Radar Measurements of Precipitation and Freezing Level in Atmospheric Rivers: Comparison With Ground‐Based Radars and Reanalyses
Authors: Cannon Forest , Ralph F. Martin , Wilson Anna M. , Lettenmaier Dennis P. 
Published: November 2017

AbstractAtmospheric rivers (ARs) account for more than 90% of the total meridional water vapor flux in midlatitudes, and 25–50% of the annual precipitation in the coastal western United States. In this study, reflectivity profiles from the Global Precipitation Measurement Dual‐Frequency Precipitation Radar (GPM‐DPR) are used to evaluate precipitation and temperature characteristics of ARs over the western coast of North America and the eastern North Pacific Ocean. Evaluation of GPM‐DPR bright‐band height using a network of ground‐based vertically pointing radars along the West Coast demonstrated exceptional agreement, and comparison with freezing level height from reanalyses over the eastern North Pacific Ocean also consistently agreed, indicating that GPM‐DPR can be used to independently validate freezing level in models. However, precipitation comparison with gridded observations across the western United States indicated deficiencies in GPM‐DPR's ability to reproduce the spatial distribution of winter precipitation, likely related to sampling frequency. Over the geographically homogeneous oceanic portion of the domain, sampling frequency was not problematic, and significant differences in the frequency and intensity of precipitation between GPM‐DPR and reanalyses highlighted biases in both satellite‐observed and modeled AR precipitation. Reanalyses precipitation rates below the minimum sensitivity of GPM‐DPR accounted for a 20% increase in total precipitation, and 25% of radar‐derived precipitation rates were greater than the 99th percentile precipitation rate in reanalyses. Due to differences in the proportions of precipitation in convective, stratiform bright‐band, and non‐bright‐band conditions, AR conditions contributed nearly 10% more to total precipitation in GPM‐DPR than reanalyses.
Effect of Hydration State of Martian Perchlorate Salts on Their Decomposition Temperatures During Thermal Extraction
Authors: Royle Samuel H. , Montgomery Wren , Kounaves Samuel P. , Sephton Mark A. 
Published: November 2017

AbstractThree Mars missions have analyzed the composition of surface samples using thermal extraction techniques. The temperatures of decomposition have been used as diagnostic information for the materials present. One compound of great current interest is perchlorate, a relatively recently discovered component of Mars' surface geochemistry that leads to deleterious effects on organic matter during thermal extraction. Knowledge of the thermal decomposition behavior of perchlorate salts is essential for mineral identification and possible avoidance of confounding interactions with organic matter. We have performed a series of experiments which reveal that the hydration state of magnesium perchlorate has a significant effect on decomposition temperature, with differing temperature releases of oxygen corresponding to different perchlorate hydration states (peak of O2 release shifts from 500 to 600°C as the proportion of the tetrahydrate form in the sample increases). Changes in crystallinity/crystal size may also have a secondary effect on the temperature of decomposition, and although these surface effects appear to be minor for our samples, further investigation may be warranted. A less than full appreciation of the hydration state of perchlorate salts during thermal extraction analyses could lead to misidentification of the number and the nature of perchlorate phases present.
A simplified Monte Carlo algorithm considering large‐angle scattering for fast and accurate calculation of proton dose
Authors: Takayanagi Taisuke , Hirayama Shusuke , Fujitaka Shinichiro , Fujimoto Rintaro 
Published: November 2017

AbstractPurposeThe purpose of this study is to improve dose calculation accuracy of the simplified Monte Carlo (SMC) algorithm in the low‐dose region. Because conventional SMC algorithms calculate particle scattering in consideration of multiple Coulomb scattering (MCS) only, they approximate lateral dose profiles by a single Gaussian function. However, it is well known that the low‐dose region spreads away from the beam axis, and it has been pointed out that modeling of the low‐dose region is important to calculated dose accurately.MethodsA SMC algorithm, which is named modified SMC and considers not only MCS but also large angle scattering resembling hadron elastic scattering, was developed. In the modified SMC algorithm, the particle fluence varies in the longitudinal direction because the large‐angle scattering decreases residual range of particles in accordance with their scattering angle and tracking of the particles with large scattering angle is terminated at a short distance downstream from the scattering. Therefore, modified integrated depth dose (m‐IDD) tables, which are converted from measured IDD in consideration of the fluence loss, are used to calculate dose.ResultsIn the case of a 1‐liter cubic target, the calculation accuracy was improved in comparison with that of a conventional algorithm, and the modified algorithm results agreed well with Geant4‐based simulation results; namely, 98.8% of the points satisfied the 2% dose/2 mm distance‐to‐agreement (DTA) criterion. The calculation time of the modified SMC algorithm was 1972 s in the case of 4.4 × 108 particles and 16‐threading operation of an Intel Xeon E5‐2643 (3.3‐GHz clock).ConclusionsAn SMC algorithm that can reproduce a laterally widespread low‐dose region was developed. According to the comparison with a Geant4‐based simulation, it was concluded that the modified SMC algorithm is useful for calculating dose of proton radiotherapy.
Evaluation of dosimetric advantages of using patient‐specific aperture system with intensity‐modulated proton therapy for the shallow depth tumor
Authors: Yasui Keisuke , Toshito Toshiyuki , Omachi Chihiro , Hayashi Kensuke , Tanaka Kenichiro , Asai Kumiko , Shimomura Akira , Muramatsu Rie , Hayashi Naoki 
Published: November 2017

AbstractIn this study, we evaluate dosimetric advantages of using patient‐specific aperture system with intensity‐modulated proton therapy (IMPT) for head and neck tumors at the shallow depth. We used four types of patient‐specific aperture system (PSAS) to irradiate shallow regions less than 4 g/cm2 with a sharp lateral penumbra. Ten head and neck IMPT plans with or without aperture were optimized separately with the same 95% prescription dose and same dose constraint for organs at risk (OARs). The plans were compared using dose volume histograms (DVHs), dose distributions, and some dose indexes such as volume receiving 50% of the prescribed dose (V50), mean or maximum dose (Dmean and Dmax) to the OARs. All examples verified in this study had decreased V50 and OAR doses. Average, maximum, and minimum relative reductions of V50 were 15.4%, 38.9%, and 1.0%, respectively. Dmax and Dmean of OARs were decreased by 0.3% to 25.7% and by 1.0% to 46.3%, respectively. The plans with the aperture over more than half of the field showed decreased V50 or OAR dose by more than 10%. The dosimetric advantage of patient‐specific apertures with IMPT was clarified in many cases. The PSAS has some dosimetric advantages for clinical use, and in some cases, it enables to fulfill dose constraints.
Ferroelectric and Magnetic Properties in Room‐Temperature Multiferroic GaxFe2−xO3 Epitaxial Thin Films
Authors: Katayama Tsukasa , Yasui Shintaro , Hamasaki Yosuke , Shiraishi Takahisa , Akama Akihiro , Kiguchi Takenori , Itoh Mitsuru 
Published: November 2017

AbstractGaFeO3‐type iron oxide is a promising room‐temperature multiferroic material due to its large magnetization. To expand its usability, controlling the ferroelectric and magnetic properties is crucial. In this study, high‐quality GaxFe2–xO3 (x = 0–1) epitaxial films are fabricated and their properties are systematically investigated. All films exhibit room‐temperature out‐of‐plane ferroelectricity, showing that the coercive electric field (Ec) decreases monotonically with x. Additionally, the films show in‐plane ferrimagnetism with a Curie temperature (TC) >350 K at x = 0–0.6. The coercive magnetic field (Hc) decreases with x at x ≤ 0.6, but shows a constant value at x > 0.6, whereas the saturated magnetization (Ms) increases with x at x ≤ 0.6, but decreases with x at x > 0.6. X‐ray magnetic circular dichroism reveals that the large magnetization at x = 0.6 is derived from Fe3+ (3d5) at octahedral sites. The controllable range of the Ec, Hc, and Ms values at room temperature (400–800 kV cm−1, 1–8 kOe, and 0.2–0.6 µB/f.u.) is very wide and differs from those of well‐known multiferroic BiFeO3. Furthermore, the GaxFe2−xO3 films exhibit room‐temperature magnetocapacitance effects, indicating that adjusting TC near room temperature is useful to achieve large room‐temperature magnetocapacitance behavior.
Photoswitchable Ultrafast Transactivator of Transcription (TAT) Targeting Effect for Nanocarrier‐Based On‐Demand Drug Delivery
Authors: Wang Junxia , Shen Song , Li Dongdong , Zhan Changyou , Yuan Youyong , Yang Xianzhu 
Published: November 2017

AbstractNanocarriers with intelligent transactivator of transcription (TAT) targeting properties are of particular interest for on‐demand drug delivery in the field of precision nanomedicine. Nevertheless, the key challenge of this strategy is the slowness of activating TAT peptide at the targeted tissue. As a proof‐of‐concept, polymeric micelles STAT‐NPIR&DOX with photoswitchable ultrafast TAT targeting effect are designed and explored. The hydrophilic shell of STAT‐NPIR&DOX consists of a TAT‐functionalized short‐chain poly(ethylene glycol) and a thermoresponsive long‐chain polyphosphoester (PPE). In nontumor tissue, the TAT peptide of STAT‐NPIR&DOX is masked by long‐chain PPE to minimize nonspecific uptake of nanocarriers. Upon near‐infrared (NIR) photoactivation, the TAT peptide is ultrafastly reexposed (within 60 s) via the collapse of thermoresponsive PPE, resulting in significantly enhanced cellular uptake of nanocarrier by tumor cells. Such photoswitchable TAT targeting effect efficiently avoids nonspecific uptake by nontumor cells and enhances tumor cell uptake, achieving tumor‐specific on‐demand drug delivery and superior anticancer efficacy. This approach using NIR light‐induced TAT targeting effect can be extended to a variety of applications for on‐demand drug delivery, which also provides new avenues for phototargeted drug delivery.
Enzyme‐Powered Nanobots Enhance Anticancer Drug Delivery
Authors: Hortelão Ana C. , Patiño Tania , Perez‐Jiménez Ariadna , Blanco Àngel , Sánchez Samuel 
Published: November 2017

AbstractThe use of enzyme catalysis to power micro‐ and nanomotors exploiting biocompatible fuels has opened new ventures for biomedical applications such as the active transport and delivery of specific drugs to the site of interest. Here, urease‐powered nanomotors (nanobots) for doxorubicin (Dox) anticancer drug loading, release, and efficient delivery to cells are presented. These mesoporous silica‐based core–shell nanobots are able to self‐propel in ionic media, as confirmed by optical tracking and dynamic light scattering analysis. A four‐fold increase in drug release is achieved by nanobots after 6 h compared to their passive counterparts. Furthermore, the use of Dox‐loaded nanobots presents an enhanced anticancer efficiency toward HeLa cells, which arises from a synergistic effect of the enhanced drug release and the ammonia produced at high concentrations of urea substrate. A higher content of Dox inside HeLa cells is detected after 1, 4, 6, and 24 h incubation with active nanobots compared to passive Dox‐loaded nanoparticles. The improvement in drug delivery efficiency achieved by enzyme‐powered nanobots may hold potential toward their use in future biomedical applications such as the substrate‐triggered release of drugs in target locations.
Probing and Manipulating the Interfacial Defects of InGaAs Dual‐Layer Metal Oxides at the Atomic Scale
Authors: Wu Xing , Luo Chen , Hao Peng , Sun Tao , Wang Runsheng , Wang Chaolun , Hu Zhigao , Li Yawei , Zhang Jian , Bersuker Gennadi , Sun Litao , Pey Kinleong 
Published: November 2017

AbstractThe interface between III–V and metal‐oxide‐semiconductor materials plays a central role in the operation of high‐speed electronic devices, such as transistors and light‐emitting diodes. The high‐speed property gives the light‐emitting diodes a high response speed and low dark current, and they are widely used in communications, infrared remote sensing, optical detection, and other fields. The rational design of high‐performance devices requires a detailed understanding of the electronic structure at this interface; however, this understanding remains a challenge, given the complex nature of surface interactions and the dynamic relationship between the morphology evolution and electronic structures. Herein, in situ transmission electron microscopy is used to probe and manipulate the structural and electrical properties of ZrO2 films on Al2O3 and InGaAs substrate at the atomic scale. Interfacial defects resulting from the spillover of the oxygen‐atom conduction‐band wavefunctions are resolved. This study unearths the fundamental defect‐driven interfacial electric structure of III–V semiconductor materials and paves the way to future high‐speed and high‐reliability devices.
Multiple Routes to Smart Nanostructured Materials from Diatom Microalgae: A Chemical Perspective
Authors: Ragni Roberta , Cicco Stefania R. , Vona Danilo , Farinola Gianluca M. 
Published: November 2017

AbstractDiatoms are unicellular photosynthetic microalgae, ubiquitously diffused in both marine and freshwater environments, which exist worldwide with more than 100 000 species, each with different morphologies and dimensions, but typically ranging from 10 to 200 µm. A special feature of diatoms is their production of siliceous micro‐ to nanoporous cell walls, the frustules, whose hierarchical organization of silica layers produces extraordinarily intricate pore patterns. Due to the high surface area, mechanical resistance, unique optical features, and biocompatibility, a number of applications of diatom frustules have been investigated in photonics, sensing, optoelectronics, biomedicine, and energy conversion and storage. Current progress in diatom‐based nanotechnology relies primarily on the availability of various strategies to isolate frustules, retaining their morphological features, and modify their chemical composition for applications that are not restricted to those of the bare biosilica produced by diatoms. Chemical or biological methods that decorate, integrate, convert, or mimic diatoms' biosilica shells while preserving their structural features represent powerful tools in developing scalable, low‐cost routes to a wide variety of nanostructured smart materials. Here, the different approaches to chemical modification as the basis for the description of applications relating to the different materials thus obtained are presented.
Confined Synthesis of Carbon Nitride in a Layered Host Matrix with Unprecedented Solid‐State Quantum Yield and Stability
Authors: Liu Wendi , Xu Simin , Guan Shanyue , Liang Ruizheng , Wei Min , Evans David G. , Duan Xue 
Published: November 2017

AbstractFluorescent carbon nanomaterials have drawn tremendous attention for their intriguing optical performances, but their employment in solid‐state luminescent devices is rather limited as a result of aggregation‐induced photoluminescence quenching. Herein, ultrathin carbon nitride (CN) is synthesized within the 2D confined region of layered double hydroxide (LDH) via triggering the interlayer condensation reaction of citric acid and urea. The resulting CN/LDH phosphor emits strong cyan light under UV‐light irradiation with an absolute solid‐state quantum yield (SSQY) of 95.9 ± 2.2%, which is, to the best of our knowledge, the highest value of carbon‐based fluorescent materials ever reported. Furthermore, it exhibits a strong luminescence stability toward temperature, environmental pH, and photocorrosion. Both experimental studies and theoretical calculations reveal that the host–guest interactions between the rigid LDH matrix and interlayer carbon nitride give the predominant contribution to the unprecedented SSQY and stability. In addition, prospective applications of the CN/LDH material are demonstrated in both white light‐emitting diodes and upconversion fluorescence imaging of cancer cells.
A Bifunctional Perovskite Promoter for Polysulfide Regulation toward Stable Lithium–Sulfur Batteries
Authors: Kong Long , Chen Xiang , Li Bo‐Quan , Peng Hong‐Jie , Huang Jia‐Qi , Xie Jin , Zhang Qiang 
Published: November 2017

AbstractLithium‐sulfur (LiS) batteries are strongly considered as the next‐generation rechargeable cells. However, both the shuttle of lithium polysulfides (LiPSs) and sluggish kinetics in random deposition of lithium sulfides (Li2S) significantly degrade the capacity, rate performance, and cycling life of LiS cells. Herein, bifunctional Ba0.5Sr0.5Co0.8Fe0.2O3−δ perovskite nanoparticles (PrNPs) are proposed as a promoter to immobilize LiPSs and guide the deposition of Li2S in a LiS cell. The oxygen vacancy in PrNPs increases the metal reactivity to anchor LiPSs, and co‐existence of lithiophilic (O) and sulfiphilic (Sr) sites in PrNP favor the dual‐bonding (LiO and SrS bonds) to anchor LiPSs. The high catalytic nature of PrNP facilitates the kinetics of LiPS redox reaction. The PrNP with intrinsic LiPS affinity serves as nucleation sites for Li2S deposition and guides its uniform propagation. Therefore, the bifunctional LiPS promoter in LiS cell yields high rate performance and ultralow capacity decay rate of 0.062% (a quarter of pristine LiS cells). The proposed strategy to immobilize LiPSs, promotes the conversion of LiPS, and regulates deposition of Li2S by an emerging perovskite promoter and is also expected to be applied in other energy conversion and storage devices based on multi‐electron redox reactions.
Epitaxial Stress‐Free Growth of High Crystallinity Ferroelectric PbZr0.52Ti0.48O3 on GaN/AlGaN/Si(111) Substrate
Authors: Li Lin , Liao Zhaoliang , Gauquelin Nicolas , Nguyen Minh Duc , Hueting Raymond J. E. , Gravesteijn Dirk J. , Lobato Ivan , Houwman Evert P. , Lazar Sorin , Verbeeck Johan , Koster Gertjan , Rijnders Guus 
Published: November 2017

AbstractDue to its physical properties gallium‐nitride (GaN) is gaining a lot of attention as an emerging semiconductor material in the field of high‐power and high‐frequency electronics applications. Therefore, the improvement in the performance and/or perhaps even extension in functionality of GaN based devices would be highly desirable. The integration of ferroelectric materials such as lead–zirconate–titanate (PbZrxTi1‐xO3) with GaN has a strong potential to offer such an improvement. However, the large lattice mismatch between PZT and GaN makes the epitaxial growth of Pb(Zr1‐xTix)O3 on GaN a formidable challenge. This work discusses a novel strain relaxation mechanism observed when MgO is used as a buffer layer, with thicknesses down to a single unit cell, inducing epitaxial growth of high crystallinity Pb(Zr0.52Ti0.48)O3 (PZT) thin films. The epitaxial PZT films exhibit good ferroelectric properties, showing great promise for future GaN device applications.
The Influence of Backbone Fluorination on the Dielectric Constant of Conjugated Polythiophenes
Authors: Boufflet Pierre , Bovo Gianluca , Occhi Luca , Yuan Hua‐Kang , Fei Zhuping , Han Yang , Anthopoulos Thomas D. , Stavrinou Paul N. , Heeney Martin 
Published: November 2017

AbstractThe ability to modify or enhance the dielectric constant of semiconducting polymers can prove valuable for a range of optoelectronic and microelectronic applications. In the case of organic photovoltaics, increasing the dielectric constant of the active layer has often been suggested as a method to control charge generation, recombination dynamics, and ultimately, the power conversion efficiencies. In this contribution, the impact that the degree and pattern of fluorination has on the dielectric constant of poly(3‐octylthiophene) (P3OT), a more soluble analogue of the widely studied conjugated material poly(3‐hexylthiophene), is explored. P3OT and its backbone‐fluorinated analogue, F‐P3OT, are compared along with a block and alternating copolymer version of these materials. It is found that the dielectric constant of the polymer thin films increases as the degree of backbone fluorination increases, in a trend consistent with density functional theory calculations of the dipole moment.