bluuebunny/crossref_metadata_2025 huggingface dataset:
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

Atmospheric 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

Three 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

Purpose

The 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.

Methods

A 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.

Results

In 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).

Conclusions

An 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

In 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.
Tailoring Microstructure and Properties of Fine Grained Magnesium Alloys by Severe Plastic Deformation
Authors: Vinogradov Alexei , Serebryany Vladimir N. , Dobatkin Sergey V.
Published: November 2017

Modern wrought magnesium alloys have poor formability at room temperature, which impedes the wider uptake of these alloys by the industry. Over the last decades, research activities in the area of magnesium alloy development have grown enormously and have produced a pallet of exciting findings, which the authors summarize in this concise review focused on the effect of the microstructure, primarily of grain size, on room temperature ductility of wrought Mg‐based alloys. Well‐established paths and modern strategies to control over the grain size distribution are discussed. It is demonstrated that the use of severe plastic deformation techniques for ultimate grain refinement in magnesium alloys opens new windows for improving their mechanical properties profile by managing both strength and ductility in a wide range. However, it is shown that grain size alone cannot be regarded as a key parameter controlling the mechanical behavior of Mg alloys. The effect of texture is of paramount importance for the overall mechanical response of Mg alloys and this may supersede the influence of grain size.
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

GaFeO3‐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

Nanocarriers 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

The 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

The 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

Diatoms 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

Fluorescent 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

Lithium‐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

Due 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

The 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.
High‐Performance and Uniform 1 cm2 Polymer Solar Cells with D1‐A‐D2‐A‐Type Random Terpolymers
Authors: Shin Injeong , Ahn Hyung ju , Yun Jae Hoon , Jo Jea Woong , Park Sungmin , Joe Sung‐yoon , Bang Joona , Son Hae Jung
Published: November 2017

For the commercial development of organic photovoltaics (OPVs), laboratory‐scale OPV technology must be translated to large area modules. In particular, it is important to develop high‐efficiency polymers that can form thick (>100 nm) bulk heterojunction (BHJ) films over large areas with optimal morphologies for charge generation and transport. Here, D1‐A‐D2‐A random terpolymers composed of 2,2′‐bithiophene with various proportions of 5,6‐difluoro‐4,7‐bis(thiophen‐2‐yl)‐2,1,3‐benzothiadiazole and 5,6‐difluoro‐2,1,3‐benzothiadiazole (FBT) are synthesized. It is found that incorporating small proportions of FBT into the polymer not only conserves the high crystallinity and favorable face‐on orientation of the D‐A copolymer FBT‐Th4 but also improves the nanoscale phase separation of the BHJ film. Consequently, the random terpolymer PDT2fBT‐BT10 exhibits a much improved solar cell efficiency of 10.31% when compared to that of the copolymer FBT‐Th4 (8.62%). Moreover, due to this polymer's excellent processability and suppressed overaggregation, OPVs with 1 cm2 active area based on 351 nm thick PDT2fBT‐BT10 BHJs exhibit high photovoltaic performance of 9.42%, whereas rapid efficiency decreases arise for FBT‐Th4‐based OPVs for film thicknesses above 300 nm. It is demonstrated that this random terpolymer can be used in large area and thick BHJ OPVs, and guidelines for developing polymers that are suitable for large‐scale printing technologies are presented.
Amorphous Tin‐Based Composite Oxide: A High‐Rate and Ultralong‐Life Sodium‐Ion‐Storage Material
Authors: Yang Xu , Zhang Rong‐Yu , Zhao Jing , Wei Zhi‐Xuan , Wang Dong‐Xue , Bie Xiao‐Fei , Gao Yu , Wang Jia , Du Fei , Chen Gang
Published: November 2017

Energy‐storage technology is moving beyond lithium batteries to sodium as a result of its high abundance and low cost. However, this sensible transition requires the discovery of high‐rate and long‐lifespan anode materials, which remains a significant challenge. Here, the facile synthesis of an amorphous Sn2P2O7/reduced graphene oxide nanocomposite and its sodium storage performance between 0.01 and 3.0 V are reported for the first time. This hybrid electrode delivers a high specific capacity of 480 mA h g−1 at a current density of 50 mA g−1 and superior rate performance of 250 and 165 mA h g−1 at 2 and 10 A g−1, respectively. Strikingly, this anode can sustain 15 000 cycles while retaining over 70% of the initial capacity. Quantitative kinetic analysis reveals that the sodium storage is governed by pseudocapacitance, particularly at high current rates. A full cell with sodium super ionic conductor (NASICON)‐structured Na3V2(PO4)2F3 and Na3V2(PO4)3 as cathodes exhibits a high energy density of over 140 W h kg−1 and a power density of nearly 9000 W kg−1 as well as stability over 1000 cycles. This exceptional performance suggests that the present system is a promising power source for promoting the substantial use of low‐cost energy storage systems.
Selenium Impregnated Monolithic Carbons as Free‐Standing Cathodes for High Volumetric Energy Lithium and Sodium Metal Batteries
Authors: Ding Jia , Zhou Hui , Zhang Hanlei , Tong Linyue , Mitlin David
Published: November 2017

Energy density (energy per volume) is a key consideration for portable, automotive, and stationary battery applications. Selenium (Se) lithium and sodium metal cathodes are created that are monolithic and free‐standing, and with record Se loading of 70 wt%. The carbon host is derived from nanocellulose, an abundant and sustainable forestry product. The composite is extremely dense (2.37 g cm−3), enabling theoretical volumetric capacity of 1120 mA h cm−3. Such architecture is fully distinct from previous Se–carbon nano‐ or micropowders, intrinsically offering up to 2× higher energy density. For Li storage, the cathode delivers reversible capacity of 1028 mA h cm−3 (620 mA h g−1) and 82% retention over 300 cycles. For Na storage, 848 mA h cm−3 (511 mA h g−1) is obtained with 98% retention after 150 cycles. The electrodes yield superb volumetric energy densities, being 1727 W h L−1 for Li–Se and 980 W h L−1 for Na–Se normalized by total composite mass and volume. Despite the low surface area, over 60% capacity is maintained as the current density is increased from 0.1 to 2 C (30 min charge) with Li or Na. Remarkably, the electrochemical kinetics with Li and Na are comparable, including the transition from interfacial to diffusional control.
Hierarchical Zn–Co–S Nanowires as Advanced Electrodes for All Solid State Asymmetric Supercapacitors
Authors: Li Chao , Balamurugan Jayaraman , Kim Nam Hoon , Lee Joong Hee
Published: November 2017

A facile two‐step strategy is developed to design the large‐scale synthesis of hierarchical, unique porous architecture of ternary metal hydroxide nanowires grown on porous 3D Ni foam and subsequent effective sulfurization. The hierarchical Zn–Co–S nanowires (NWs) arrays are directly employed as an electrode for supercapacitors application. The as‐synthesized Zn–Co–S NWs deliver an ultrahigh areal capacity of 0.9 mA h cm−2 (specific capacity of 366.7 mA h g−1) at a current density of 3 mA cm−2, with an exceptional rate capability (≈227.6 mA h g−1 at a very high current density of 40 mA cm−2) and outstanding cycling stability (≈93.2% of capacity retention after 10 000 cycles). Most significantly, the assembled Zn–Co–S NWs//Fe2O3@reduced graphene oxide asymmetric supercapacitors with a wide operating potential window of ≈1.6 V yield an ultrahigh volumetric capacity of ≈1.98 mA h cm−3 at a current density of 3 mA cm−2, excellent energy density of ≈81.6 W h kg−1 at a power density of ≈559.2 W kg−1, and exceptional cycling performance (≈92.1% of capacity retention after 10 000 cycles). This general strategy provides an alternative to design the other ternary metal sulfides, making it facile, free‐standing, binder‐free, and cost‐effective ternary metal sulfide‐based electrodes for large‐scale applications in modern electronics.
An empirical analysis of U.K. milk contract prices 2004–2016
Authors: Costa‐Font Montserrat , Revoredo‐Giha Cesar
Published: November 2017

Milk quotas were introduced in 1984 to the EU dairy market to control the structural surpluses resulting from imbalances between supply and demand for milk encouraged by subsidies to the sector. These quotas were abolished on the 31st of March 2015, leaving the sector to operate closer to free market conditions. Milk in the United Kingdom is marketed through contracts and the purpose of this paper is to analyze, using time series methods, to what extent market factors are driving the observed evolution of U.K. contract prices. The five groups of contracts considered are: retailers’ aligned contracts, standard liquid contracts, A&B contracts, cheese manufacturing contracts, and other manufacturing contracts. Results indicate that, although market factors play a role in influencing all contract prices, their effect is different by type of contract, and quota abolition does not have a significant effect on the time series behavior of contract prices. [EconLit citations: M31; L11].
Der Immuncheckpoint PD‐1/PD‐L1: Gibt es Therapieoptionen jenseits der Antikörper?
Authors: Konstantinidou Markella , Zarganes‐Tzitzikas Tryfon , Magiera‐Mularz Katarzyna , Holak Tad A. , Dömling Alexander
Published: November 2017

Die PD‐1/PD‐L1‐Wechselwirkung hat sich als ein wichtiger Angriffspunkt für die Krebs‐Immuntherapie erwiesen. Aktuelle Medikationen unter Einbeziehung monoklonaler Antikörper zeigen eindrucksvolle klinische Wirkungen beim Einsatz gegen verschiedene Tumortypen. Von der Cokristallstruktur von humanem PD‐1 mit PD‐L1 erwartet man – zusammen mit den aktuellen Kristallstrukturen mit monoklonalen Antikörpern, niedermolekularen Substanzen und Makrocyclen – einen wertvollen Ausgangspunkt für den Entwurf neuer Inhibitoren.
Asymmetric Synthesis of 2H‐Azirines with a Tetrasubstituted Stereocenter by Enantioselective Ring Contraction of Isoxazoles
Authors: Okamoto Kazuhiro , Nanya Atsushi , Eguchi Akira , Ohe Kouichi
Published: November 2017

Highly strained 2H‐azirines with a tetrasubstituted stereocenter were synthesized by the enantioselective isomerization of isoxazoles with a chiral diene–rhodium catalyst system. The effect of ligands and the coordination behavior support the proposed catalytic cycle in which the coordination site is fixed in favor of efficient enantiodiscrimination by a bulky substituent of the ligand. In silico studies also support the existence of a rhodium–imido complex as a key intermediate for enantiodiscrimination.
A Chiral Halogen‐Bonding [3]Rotaxane for the Recognition and Sensing of Biologically Relevant Dicarboxylate Anions
Authors: Lim Jason Y. C. , Marques Igor , Félix Vítor , Beer Paul D.
Published: November 2017

The unprecedented application of a chiral halogen‐bonding [3]rotaxane host system for the discrimination of stereo‐ and E/Z geometric isomers of a dicarboxylate anion guest is described. Synthesised by a chloride anion templation strategy, the [3]rotaxane host recognises dicarboxylates through the formation of 1:1 stoichiometric sandwich complexes. This process was analysed by molecular dynamics simulations, which revealed the critical synergy of halogen and hydrogen bonding interactions in anion discrimination. In addition, the centrally located chiral (S)‐BINOL motif of the [3]rotaxane axle component facilitates the complexed dicarboxylate species to be sensed via a fluorescence response.
Two Distinct Substrate Binding Modes for the Normal and Reverse Prenylation of Hapalindoles by the Prenyltransferase AmbP3
Authors: Wong Chin Piow , Awakawa Takayoshi , Nakashima Yu , Mori Takahiro , Zhu Qin , Liu Xinyu , Abe Ikuro
Published: November 2017

The cyanobacterial prenyltransferase AmbP3 catalyzes the reverse prenylation of the tetracyclic indole alkaloid hapalindole U at its C‐2 position. Interestingly, AmbP3 also accepts hapalindole A, a halogenated C‐10 epimer of hapalindole U, and catalyzes normal prenylation at its C‐2 position. The comparison of the two ternary crystal structures, AmbP3‐DMSPP/hapalindole U and AmbP3‐DMSPP/hapalindole A, at 1.65–2.00 Å resolution revealed two distinct orientations for the substrate binding that define reverse or normal prenylation. The tolerance of the enzyme for these altered orientations is attributed to the hydrophobicity of the substrate binding pocket and the plasticity of the amino acids surrounding the allyl group of the prenyl donor. This is the first study to provide the intimate structural basis for the normal and reverse prenylations catalyzed by a single enzyme, and it offers novel insight into the engineered biosynthesis of prenylated natural products.
Purely Physisorption‐Based CO‐Selective Gate‐Opening in Microporous Organically Pillared Layered Silicates
Authors: Herling Markus M. , Rieß Martin , Sato Hiroshi , Li Liangchun , Martin Thomas , Kalo Hussein , Matsuda Ryotaro , Kitagawa Susumu , Breu Josef
Published: November 2017

Separation of gas molecules with similar physical and chemical properties is challenging but nevertheless highly relevant for chemical processing. By introducing the elliptically shaped molecule, 1,4‐dimethyl‐1,4‐diazabicyclo[2.2.2]octane, into the interlayer space of a layered silicate, a two‐dimensional microporous network with narrow pore size distribution is generated (MOPS‐5). The regular arrangement of the pillar molecules in MOPS‐5 was confirmed by the occurrence of a 10 band related to a long‐range pseudo‐hexagonal superstructure of pillar molecules in the interlayer space. Whereas with MOPS‐5 for CO2 adsorption, gate‐opening occurs at constant volume by freezing pillar rotation, for CO the interlayer space is expanded at gate‐opening and a classical interdigitated layer type of gate‐opening is observed. The selective nature of the gate‐opening might be used for separation of CO and N2 by pressure swing adsorption.
Hierarchical Hollow Nanoprisms Based on Ultrathin Ni‐Fe Layered Double Hydroxide Nanosheets with Enhanced Electrocatalytic Activity towards Oxygen Evolution
Authors: Yu Le , Yang Jing Fan , Guan Bu Yuan , Lu Yan , Lou Xiong Wen (David)
Published: November 2017

The oxygen evolution reaction (OER) is involved in various renewable energy systems, such as water‐splitting cells and metal–air batteries. Ni‐Fe layered double hydroxides (LDHs) have been reported as promising OER electrocatalysts in alkaline electrolytes. The rational design of advanced nanostructures for Ni‐Fe LDHs is highly desirable to optimize their electrocatalytic performance. Herein, we report a facile self‐templated strategy for the synthesis of novel hierarchical hollow nanoprisms composed of ultrathin Ni‐Fe LDH nanosheets. Tetragonal nanoprisms of nickel precursors were first synthesized as the self‐sacrificing template. Afterwards, these Ni precursors were consumed during the hydrolysis of iron(II) sulfate for the simultaneous growth of a layer of Ni‐Fe LDH nanosheets on the surface. The resultant Ni‐Fe LDH hollow prisms with large surface areas manifest high electrocatalytic activity towards the OER with low overpotential, small Tafel slope, and remarkable stability.
Valorization of waste thermoset material as a filler in thermoplastic: Mechanical properties of phenolic molding compound waste‐filled PP composites
Authors: Bernardeau Fabien , Perrin Didier , Caro Anne‐Sophie , Benezet Jean‐Charles , Ienny Patrick
Published: November 2017

As most thermoset material, phenolic molding compound (PMC) wastes are an environmental problem. Very few recycling solutions have been proposed so far for this type of material. A mechanical recycling method to valorize these materials is proposed in this work. It relies on the use of phenolic waste as filler in thermoplastic. Such phenolic filler can increase mechanical properties (tensile, flexural) of the matrix, and be used in substitution of traditional particulate fillers such as calcium carbonate or talc. In this study, several morphological parameters influencing the final mechanical properties of a PMC‐filled polypropylene (PP) micro‐composite are studied, such as filler loading rate, particles size distribution of the filler, and interfacial adhesion between the filler and the matrix. Some structural parameters are also studied and linked with mechanical properties, such as dispersion of the filler and crystallinity of the matrix. Finally, the properties of PMC‐filled PP are compared with CaCO3‐ and talc‐filled PP. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 45849.
Evolution of double crystal melting peak in polypropylene foam assisted by β‐nucleating agent and supercritical CO2
Authors: Yu Kesong , Jiang Hanchuan , Zhou Hongfu , Mi Jianguo , He Yadong , Wang Xiangdong
Published: November 2017

Polypropylene (PP) foams with double crystal melting peak structure were prepared using supercritical CO2 as blowing agent. Such structure was induced by the β‐nucleating agent (NA) and dissolved CO2 in a lab‐scale autoclave system. From the dynamic rheological behaviors, one can see that long chain branching polypropylene (LCBPP) possess better melt elasticity than linear polypropylene (LPP). In order to improve the foamability, LPP was blended with LCBPP. The results of differential scanning calorimeter and wide‐angle X‐ray diffraction indicated that NA was helpful for the introduction of β‐crystal in LPP, but not for LCBPP and PP blends. Therefore, the foamability and the content of β‐crystal of various PP foams can be effectively controlled by adjusting the ratio of LPP and LCBPP. Meanwhile, both the cooling rate and the content of NA affected the formation of β‐crystal in various PP samples. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46007.
Electrochromic properties of some bis‐chalcone derivatives‐based nanofibers
Authors: Nohut Maşlakcı Neslihan , Biçer Abdullah , Turgut Cin Günseli , Uygun Öksüz Ayşegül
Published: November 2017

Two bis‐chalcone derivatives, (2E,6E)‐2,6‐bis[(thiophen‐2‐yl)methylene]cyclohexanone (C1) and (2E,6E)‐2,6‐bis[(furan‐2‐yl)methylene]cyclohexanone (C2)‐based electrochromic (EC) nanofibers were produced in the presence of poly(methyl methacrylate) (PMMA) as supporting polymer using the electrospinning technique. The scanning electron microscopy (SEM) and energy dispersive X‐ray spectroscopy were used to examine morphology and chemical compositions of nanofibers before and after stability test. SEM images of the obtained smooth and bead‐free nanofibers before the stability test showed that both bis‐chalcone derivatives were homogeneously dispersed on the surface of the electrospun nanofibers. Nanofibers of bis‐chalcone derivatives were characterized with Fourier‐transform infrared spectroscopy. The electrochemical and EC properties of these bis‐chalcone derivatives were investigated. The C1‐PMMA nanofiber‐based electrochromic device (ECD) showed higher ΔTmax (41.47%) than that of the C2‐PMMA nanofiber‐based ECD (4.67%) during coloration/bleaching at 715 nm. The switching times for coloration and bleaching of C1‐PMMA nanofiber‐based ECD were found to be 4.42 and 1.12 s, respectively, and the coloration efficiency was 136.18 cm2/C. Repeated cyclic voltammograms and 1000 cycles of chronoamperometric measurements of the bis‐chalcone derivatives indicated that ECDs have long‐term redox stability. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46010.
Incorporation of carbon nanofibers into a Matrimid polymer matrix: Effects on the gas permeability and selectivity properties
Authors: Dohade Manisha
Published: November 2017

Composite membranes containing carbon nanofibers (CNFs) and Matrimid were prepared by a solution‐casting method. Prepared Matrimid–CNF composite membranes were characterized with X‐ray diffraction, thermogravimetric analysis, differential scanning calorimetry, Fourier transform infrared spectroscopy, scanning electron microscopy, transmission electron microscopy, and mechanical testing techniques. The mechanical properties of the composite membranes increased over that of the pristine polymeric membranes. To develop a broad fundamental understanding of the connection between the composite architecture and gas‐transport properties, both the gas‐permeability and gas‐separation characteristics were evaluated. The gas‐transport properties of the Matrimid–CNF composite membrane was measured with a single gas‐permeation setup (He, H2, N2, CH4 and CO2) at ambient temperature with the variable‐volume method. The incorporation of CNFs (0.5–10 wt %) into the Matrimid matrix resulted in approximately a 22% reduction in the gas permeation of various gases, (H2, He, CO2, N2, and CH4). Moreover, an improvement of 1.5 times in the gas selectivity was observed for CO2/CH4, H2/CH4, He/CH4, and H2/N2 compared to pristine polymeric membrane. Hence, such polymer–CNF composite membranes could be suitable for gas‐separation applications with high purity requirements. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46019.
Toughness of ABS/PBT blends: The relationship between composition, morphology, and fracture behavior
Authors: Tang Lei , Wang Lulin , Chen Pingxu , Fu Jinfeng , Xiao Peng , Ye Nanbiao , Zhang Mingqiu
Published: November 2017

A series of acrylonitrile–butadiene–styrene (ABS) copolymer/poly(butylene terephthalate) (PBT)/acrylonitrile‐styrene‐glycidyl methacrylate (ASG) blends with various compositions were prepared and characterized in this study. When the fraction of ABS exceeds a critical value there is a rapid increase in notched impact strength of ABS/PBT blends no matter whether the compatibilizer ASG is present. By combining morphology observation and notched impact results, we found that the ductile‐brittle transition of the blends is closely related to the morphology inversion. The notched impact strength jumps from 15.9 to 33.4 kJ/m2 when phase inversion of ABS occurs at its fraction of 58 wt %. Accordingly, a possible toughening mechanism involved in the blends is proposed on the basis of a careful analysis of fracture energy, crack propagation behavior and fracture surface morphology. It is believed that the continuous ABS phase plays the critical role in toughening ABS/PBT blends. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2018, 135, 46051.
The interrupted learner: How distractions during live and video lectures influence learning outcomes
Authors: Zureick Andrew H. , Burk‐Rafel Jesse , Purkiss Joel A. , Hortsch Michael
Published: November 2017

New instructional technologies have been increasingly incorporated into the medical school learning environment, including lecture video recordings as a substitute for live lecture attendance. The literature presents varying conclusions regarding how this alternative experience impacts students' academic success. Previously, a multi‐year study of the first‐year medical histology component at the University of Michigan found that live lecture attendance was positively correlated with learning success, while lecture video use was negatively correlated. Here, three cohorts of first‐year medical students (N = 439 respondents, 86.6% response rate) were surveyed in greater detail regarding lecture attendance and video usage, focusing on study behaviors that may influence histology learning outcomes. Students who reported always attending lectures or viewing lecture videos had higher average histology scores than students who employed an inconsistent strategy (i.e., mixing live attendance and video lectures). Several behaviors were negatively associated with histology performance. Students who engaged in “non‐lecture activities” (e.g., social media use), students who reported being interrupted while watching the lecture video, or feeling sleepy/losing focus had lower scores than their counterparts not engaging in these behaviors. This study suggests that interruptions and distractions during medical learning activities—whether live or recorded—can have an important impact on learning outcomes. Anat Sci Educ 11: 366–376. © 2017 American Association of Anatomists.
Experimental and Theoretical Study of Enhanced Photocatalytic Activity of Mg‐Doped ZnO NPs and ZnO/rGO Nanocomposites
Authors: Yousefi Ramin , Beheshtian Javad , Seyed‐Talebi Seyedeh Mozhgan , Azimi H. R. , Jamali‐Sheini Farid
Published: November 2017

A systematic experimental and theoretical study of the origin of the enhanced photocatalytic performance of Mg‐doped ZnO nanoparticles (NPs) and Mg‐doped ZnO/reduced graphene oxide (rGO) nanocomposites has been performed. In addition to Mg, Cd was chosen as a doping material for the bandgap engineering of ZnO NPs, and its effects were compared with that of Mg in the photocatalytic performance of ZnO nanostructures. The experimental results revealed that Mg, as a doping material, recognizably ameliorates the photocatalytic performance of ZnO NPs and ZnO/graphene nanocomposites. Transmission electron microscopy (TEM) images showed that the Mg‐doped and Cd‐doped ZnO NPs had the same size. The optical properties of the samples indicated that Cd narrowed the bandgap, whereas Mg widened the bandgap of the ZnO NPs and the oxygen vacancy concentration was similar for both samples. Based on the experimental results, the narrowing of the bandgap, the particle size, and the oxygen vacancy did not enhance the photocatalytic performance. However, Brunauer–Emmett–Teller (BET) and Barret–Joyner–Halenda (BJH) models showed that Mg caused increased textural properties of the samples, whereas rGO played an opposite role. A theoretical study, conducted by using DFT methods, showed that the improvement in the photocatalytic performance of Mg‐doped ZnO NPs was due to a higher electron transfer from the Mg‐doped ZnO NPs to the dye molecules compared with pristine ZnO and Cd‐doped ZnO NPs. Moreover, according to the experimental results, along with Mg, graphene also played an important role in the photocatalytic performance of ZnO.
An integrative framework for studying, designing and conceptualising interactivity in children's digital books
Authors: Kucirkova Natalia
Published: November 2017

In the past five years, there have been significant changes concerning the material and design properties of digital books, with an impact on children's enjoyment and learning from reading on screen. Despite the rapid advances in technology, research on children's digital books is disjointed. This is because of no consistent approach to the study of interactivity, an under‐theorised relationship between print and digital books, and a binary design focused on either learning or playful engagement with digital books. Drawing on the discourse reminiscent of digital game designers, some developers, scholars and professionals celebrate interactivity in digital books as a possibility to motivate and engage children in reading, while a body of experimental research documents the negative impact of interactivity on children's story comprehension and vocabulary learning. This paper presents an integrative framework based on a comprehensive literature review and a content review of the hundred most popular children's digital interactive books. The framework offers: (1) methodological guidance and a definition of interactivity based on five key categories; (2) theoretical guidance based on the third‐space theory; and (3) innovative design and evaluation models based on a ‘method assemblage’. As such, the integrative framework provides new tools and perspectives to advance the field of children's digital books.