bluuebunny/crossref_metadata_2025 huggingface dataset:
Halauxifen-methyl preplant intervals and environmental conditions in soybean
Authors: Zimmer Marcelo , Young Bryan G. , Johnson William G.
Published: July 2019

Synthetic-auxin herbicides are often applied for horseweed control before soybean planting. However, certain days of planting interval must be maintained before soybean planting, depending on the product and rate used, because of potential crop phytotoxicity. Halauxifen-methyl is a new synthetic-auxin herbicide for horseweed control in preplant applications in soybean. Field experiments were conducted in 2015 and 2016 in Indiana to evaluate soybean phytotoxicity in response to applications of halauxifen-methyl (5 g ae ha−1) at five preplant intervals (0, 1, 2, 3, and 4 weeks before planting [WBP]). In 2015, soybean phytotoxicity was not observed for any of the preplant intervals at any of the sites. In 2016, 0% to 15% phytotoxicity was observed at 14 d after planting (DAP) when halauxifen-methyl was applied at planting, 1 WBP, and 2 WBP at different sites. Soybean phytotoxicity was expressed in the unifoliate leaves only at 14 DAP. However, the first trifoliate did not show any injury symptoms at 21 DAP from any preplant application timing. Preplant application intervals for halauxifen-methyl did not affect soybean stand counts or grain yield in any site-year. Therefore, field results indicated that halauxifen-methyl applied alone can cause slight soybean phytotoxicity in preplant applications. In growth-chamber bioassays, reductions in soybean biomass, plant length, and emergence were accentuated at 30 C, compared with 20 or 15 C, when halauxifen-methyl was applied at 20 or 40 g ae ha−1. These results contradict the currently held paradigm in which lower temperatures generally increase crop phytotoxicity levels to herbicide soil residual.
The Microphysics of Stratiform Precipitation During OLYMPEX: Compatibility Between Triple‐Frequency Radar and Airborne In Situ Observations
Authors: Tridon Frédéric , Battaglia Alessandro , Chase Randy J. , Turk F. Joseph , Leinonen Jussi , Kneifel Stefan , Mroz Kamil , Finlon Joseph , Bansemer Aaron , Tanelli Simone , Heymsfield Andrew J. , Nesbitt Stephen W.
Published: July 2019

The link between stratiform precipitation microphysics and multifrequency radar observables is thoroughly investigated by exploiting simultaneous airborne radar and in situ observations collected from two aircraft during the OLYMPEX/RADEX (Olympic Mountain Experiment/Radar Definition Experiment 2015) field campaign. Above the melting level, in situ images and triple‐frequency radar signatures both indicate the presence of moderately rimed aggregates. Various mass‐size relationships of ice particles and snow scattering databases are used to compute the radar reflectivity from the in situ particle size distribution. At Ku and Ka band, the best agreement with radar observations is found when using the self‐similar Rayleigh‐Gans approximation for moderately rimed aggregates. At W band, a direct comparison is challenging because of the non‐Rayleigh effects and of the probable attenuation due to ice aggregates and supercooled liquid water between the two aircraft. A variational method enables the retrieval of the full precipitation profile above and below the melting layer, by combining the observations from the three radars. Even with three radar frequencies, the retrieval of rain properties is challenging over land, where the integrated attenuation is not available. Otherwise, retrieved mean volume diameters and water contents of both solid and liquid precipitation are in agreement with in situ observations and indicate local changes of the degree of riming of ice aggregates, on the scale of 5 km. Finally, retrieval results are analyzed to explore the validity of using continuity constraints on the water mass flux and diameter within the melting layer in order to improve retrievals of ice properties.
Importance of Surface Roughness for the Local Biogeophysical Effects of Deforestation
Authors: Winckler J. , Reick C. H. , Bright R. M. , Pongratz J.
Published: July 2019

Deforestation influences surface properties such as surface roughness, resulting in changes in the surface energy balance and surface temperature. Recent studies suggest that the biogeophysical effects are dominated by changing roughness, and it remains unclear whether this can be reconciled with earlier modeling studies that highlighted the importance of a reduction of evapotranspiration in the low latitudes and a reduction of net shortwave radiation at the surface in the high latitudes. To clarify this situation, we analyze the local effects of deforestation on surface energy balance and temperature in the MPI‐ESM climate model by performing three separate experiments: switching from forest to grass all surface properties, only surface albedo, and only surface roughness. We find that the locally induced changes in surface temperature are dominated by changes in surface roughness for the annual mean, the response of the diurnal amplitude, and the seasonal response to deforestation. For these three quantities, the results of the MPI‐ESM lie within the range of observation‐based data sets. Deforestation‐induced decreases in surface roughness contribute substantially to winter cooling in the boreal regions and to decreases in evapotranspiration in the tropics. By comparing the energy balance decompositions from the three experiments, the view that roughness changes dominate the biogeophysical consequences of deforestation can be reconciled with the earlier studies highlighting the relevance of evapotranspiration.
Comment on “U.S. Urban Water Prices: Cheaper When Drier” by Ian H. Luby, Stephen Polasky, and Deborah L. Swackhamer
Authors: Switzer David , Teodoro Manuel P.
Published: July 2019

In a recent article in this journal, Luby, Polasky, and Swackhamer come to the provocative conclusion that urban water prices in the United States are “cheaper when drier.” They also argue that utilities fail to provide affordable water and that they charge less for “additional” use compared to “essential” use. We challenge these claims. While the authors correctly point out the many challenges that utilities face in supplying affordable water while meeting conservation and revenue goals, there are serious flaws in their measures of price, scarcity, and affordability. These measurement problems lead the authors to incorrect conclusions about water pricing in the United States. Using improved measures of price and water scarcity, we find little statistical relationship between the marginal price of water/sewer services and scarcity. Our findings cast doubt on Luby et al.'s findings and point to important avenues for future research.
How Satellite Data Improve Earthquake Monitoring
Authors: Crowell Rachel
Published: July 2019

Case studies from around the world illustrate the power of geodetic data in earthquake monitoring.
Apollo 11 at 50 and Other Things We’re Reading This Week
Authors:   AGU
Published: July 2019

What Earth and space science stories are Eos staffers recommending this week?
On the response of Martian Ionosphere to the Passage of a Corotating Interaction Region: MAVEN Observations
Authors: Krishnaprasad C. , Thampi Smitha V. , Bhardwaj Anil
Published: July 2019

The response of Martian ionosphere to the passage of corotating interaction region (CIR) of June 2015 is studied using observations from several instruments aboard the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission. An intense CIR arrived at Mars on 22 June 2015, during which the upstream solar wind and interplanetary magnetic field conditions were monitored by the Solar Wind Ion Analyzer (SWIA), Solar Wind Electron Analyzer (SWEA), Solar Energetic Particle (SEP), and Magnetometer (MAG) instruments aboard MAVEN. The CIR event was characterized by enhancements in solar wind density, velocity, and dynamic pressure, and increased and fluctuating interplanetary magnetic field and was associated with enhanced fluxes of Solar Energetic Particles. The Langmuir Probe and Waves (LPW) instrument onboard MAVEN provided the ionospheric observations such as electron density and electron temperature during this period. The dayside ionosphere is significantly compressed only near the peak of solar wind dynamic pressure enhancement (∼14 nPa). In contrast, on the nightside, the electron density remains depleted for a longer period of time. The electron temperatures are also enhanced during the period of electron depletion on the nightside. The Suprathermal and Thermal Ion Composition (STATIC) measurements show enhanced fluxes of suprathermal heavy ions in the Martian exosphere during CIR period, and evidences for enhanced tailward flow of these pickup ions. The analysis suggests that the nightside ionosphere is primarily controlled by the precipitating Solar Energetic Particles and pickup ions transported across the Martian terminator and depletes significantly when the heavy ion flux in the exosphere enhances.
Particulate Backscattering Ratio as an Indicator of Changing Particle Composition in Coastal Waters: Observations From Great Barrier Reef Waters
Authors: Soja‐Woźniak Monika , Baird Mark , Schroeder Thomas , Qin Yi , Clementson Lesley , Baker Brett , Boadle David , Brando Vittorio , Steven Andy D. L.
Published: July 2019

Particle scattering is an important process that determines both the light penetration through the water column and water‐leaving light. Backscattering, in combination with absorption, determines the remote‐sensing reflectance that is used in ocean color algorithms. Additionally, the wavelength dependence of the backscattering ratio can be related to the particle composition in seawater. Here, we examine the magnitude and the spectral behavior of the backscattering ratio against other bio‐optical properties based on a comprehensive set of continuous measurements collected in coastal waters of the Great Barrier Reef over 3 years. The site is located offshore of a major river, and close to the cross‐shelf transition of bottom sediments from terrigenous muds to marine carbonates. The backscattering ratio measured at 650 nm clearly clustered the data into two types. Type 1, which we identified as terrigenous mud with a low organic fraction, is characterized by backscattering ratio below 0.011 with a mean value of 0.005. Type 2, which we identified as marine carbonate with a higher organic fraction, has backscattering ratio above 0.011 with a mean value of 0.02. Within 3 years, study site was exposed to type 1‐dominated particles 13% of the time, and type 2 87%. The observed changes in the backscattering ratio at this one coastal site are as large as the variability seen throughout the global ocean. This work provides a better understanding of processes determining the optical characteristics and insights into optical parameterizations that can be used in process‐based optical modeling of the Great Barrier Reef.
Lagrangian Views of the Pathways of the Atlantic Meridional Overturning Circulation
Authors: Bower A. , Lozier S. , Biastoch A. , Drouin K. , Foukal N. , Furey H. , Lankhorst M. , Rühs S. , Zou S.
Published: July 2019

The Lagrangian method—where current location and intensity are determined by tracking the movement of flow along its path—is the oldest technique for measuring the ocean circulation. For centuries, mariners used compilations of ship drift data to map out the location and intensity of surface currents along major shipping routes of the global ocean. In the mid‐20th century, technological advances in electronic navigation allowed oceanographers to continuously track freely drifting surface buoys throughout the ice‐free oceans and begin to construct basin‐scale, and eventually global‐scale, maps of the surface circulation. At about the same time, development of acoustic methods to track neutrally buoyant floats below the surface led to important new discoveries regarding the deep circulation. Since then, Lagrangian observing and modeling techniques have been used to explore the structure of the general circulation and its variability throughout the global ocean, but especially in the Atlantic Ocean. In this review, Lagrangian studies that focus on pathways of the upper and lower limbs of the Atlantic Meridional Overturning Circulation (AMOC), both observational and numerical, have been gathered together to illustrate aspects of the AMOC that are uniquely captured by this technique. These include the importance of horizontal recirculation gyres and interior (as opposed to boundary) pathways, the connectivity (or lack thereof) of the AMOC across latitudes, and the role of mesoscale eddies in some regions as the primary AMOC transport mechanism. There remain vast areas of the deep ocean where there are no direct observations of the pathways of the AMOC.
Quantifying the Relative Importance of Riverine and Open‐Ocean Nitrogen Sources for Hypoxia Formation in the Northern Gulf of Mexico
Authors: Große Fabian , Fennel Katja , Laurent Arnaud
Published: July 2019

The Mississippi and Atchafalaya River System discharges large amounts of freshwater and nutrients into the northern Gulf of Mexico (NGoM). These lead to increased stratification and elevate primary production in the outflow region. Consequently, hypoxia (oxygen <62.5 mmol/m3), extending over an area of roughly 15,000 km2, forms every summer in bottom waters. High‐resolution models have significantly improved our understanding of the processes controlling hypoxia formation in the NGoM and have strongly implicated riverine nutrients as the dominant nutrient source. However, the relative importance of different nutrient sources (i.e., the Mississippi and Atchafalaya Rivers and offshore) has not been assessed before now. Here, we combine a high‐resolution model with an element tracing method to directly quantify the relative contributions of nitrogen from the two rivers and the open ocean to primary production and sediment oxygen consumption, which is the main oxygen sink contributing to hypoxia in the NGoM. Our results indicate that, averaged over 2001–2011, Mississippi and Atchafalaya nitrogen support 51 ± 9% and 33 ± 9% of summer sediment oxygen consumption, respectively, while open‐ocean nitrogen supports 16 ± 2%. The higher relative impact of Mississippi inputs results from longer transit times compared to those of Atchafalaya inputs. We also analyze the effect of riverine nitrogen load reductions and a larger diversion of discharge to the Atchafalaya River. These scenario simulations show that nutrient load reductions are most effective in mitigating hypoxia.
Deformation of a Warm Eddy in the Northern South China Sea
Authors: Qiu Chunhua , Mao Huabin , Liu Hailong , Xie Qiang , Yu Jiancheng , Su Danyi , Ouyang Juan , Lian Shumin
Published: July 2019

Mesoscale eddies are important for regulating oceanic energy. Variation in eddy shapes leads to uncertainty in calculations of heat or energy content. In this study, we investigated the deformation of a warm eddy in the northern South China Sea from April to June 2018 and elucidated the mechanism governing the deformation. Satellite altimetry images showed that the warm eddy originated from Luzon Strait (LS eddy), migrated westward, and then moved along 500‐m isobaths until it approached the east of Hainan Island. Thereafter, the LS eddy deformed, moved southward, merged with other eddies, and finally dissipated. Using ship and virtual‐mooring Chinese underwater glider observations, we examined the three‐dimensional structure of the LS eddy. The warm eddy had a low‐density core that reached a depth of 250 m. The LS eddy gave rise to a front along its eastern edge, and two associate submesoscale eddies with horizontal radii of approximately 10 km were found at the front. The warm eddy was circular before deformation but morphed into an egg shape after deformation. This shape change allowed the eddy to entrain additional water mass (approximately 1014 kg). The deformation event was able to be forecasted by the vorticity and deformation index, as the eddy deformed by leaking into the zone with a high vorticity and deformation index. We used modeling and energy transformation calculations to analyze the mechanism of the warm eddy deformation. Our results revealed that baroclinic instability played a primary role in the deformation event.
Cassini UVIS Detection of Saturn's North Polar Hexagon in the Grand Finale Orbits
Authors: Pryor W. R. , Esposito L. W. , Jouchoux A. , West R. A. , Grodent D. , Gérard J.‐C. , Radioti A. , Lamy L. , Koskinen T.
Published: July 2019

Cassini's final orbits in 2016 and 2017 provided unprecedented spatial resolution of Saturn's polar regions from near‐polar spacecraft viewing geometries. Long‐wavelength channels of Cassini's Ultraviolet Imaging Spectrograph instrument detected Saturn's UV‐dark north polar hexagon near 180 nm at planetocentric latitudes near 75°N. The dark polar hexagon is surrounded by a larger, less UV‐dark collar poleward of planetocentric latitude 65°N associated with the dark north polar region seen in ground‐based images. The hexagon is closely surrounded by the main arc of Saturn's UV aurora. The UV‐dark material was locally darkest on one occasion (23 January 2017) at the boundary of the hexagon; in most Ultraviolet Imaging Spectrograph images the dark material more uniformly fills the hexagon. The observed UV‐dark stratospheric material may be a hydrocarbon haze produced by auroral ion‐neutral chemistry at submicrobar pressure levels. Ultraviolet Imaging Spectrograph polar observations are sensitive to UV‐absorbing haze particles at pressures lower than about 10–20 mbar.
Sensitivity of Limited Area Atmospheric Simulations to Lateral Boundary Conditions in Idealized Experiments
Authors: Leps Nora , Brauch Jennifer , Ahrens Bodo
Published: July 2019

The goal of limited area models (LAMs) is to downscale coarse‐gridded general circulation model output to represent small‐scale features of weather and climate. The LAM needs information from the driving coarse‐gridded model passing through its lateral boundaries. The treatment of this information transfer causes inconsistencies between driving and nested models and, subsequently, issues in regional weather and climate simulations. This work examines errors arising from choices taken by the modeler (temporal update frequency of boundary data, spatial resolution jump, and numerical lateral boundary formulation) systematically in an idealized simulation environment. So‐called Big‐Brother Experiments were performed with the LAM COSMO‐CLM (0.11° grid spacing). A baroclinic wave in a zonal channel was simulated over flat terrain with and without a Gaussian hill. The results reveal that the quality of the driving data, here represented by simulations only differing from the LAM simulations by reduced spatial resolution, dominates the performance of the nested model. Consequently, at the simulated mesoscale, the performance of the nested small‐scale model simulations is weakly sensitive to the numerical lateral boundary formulation (Davies relaxation or the newly implemented, computationally less demanding Mesinger Eta‐model formulation). The performance sensitivity to boundary update frequency and resolution jump is small when at least 6‐hourly updates and a resolution jump factor of maximally six is used. Gaussian hill LAM simulations illustrated the strength of downscaling; they can represent small‐scale features missing in the coarse‐scale driving simulations. In the idealized simulation experiments, spectral nudging is not advisable as it imprints the driving models deficits on the nested simulation.
Acetate attenuates inflammasome activation through GPR43-mediated Ca2+-dependent NLRP3 ubiquitination
Authors: Xu Mengda , Jiang Zhengyu , Wang Changli , Li Na , Bo Lulong , Zha Yanping , Bian Jinjun , Zhang Yan , Deng Xiaoming
Published: July 2019

Acetate has been indicated to be elevated and to regulate inflammation in inflammatory and metabolic diseases. The inflammasome serves as a key component of immune homeostasis, and its dysregulation can lead to various inflammatory disorders. However, little is known about the effects of acetate on inflammasome activation and the underlying mechanism. Here, we demonstrate that acetate attenuates inflammasome activation via GPR43 in a Ca2+-dependent manner. Through binding to GPR43, acetate activates the Gq/11 subunit and subsequent phospholipase C-IP3 signaling to decrease Ca2+ mobilization. In addition, acetate activates soluble adenylyl cyclase (sAC), promotes NLRP3 inflammasome ubiquitination by PKA, and ultimately induces NLRP3 degradation through autophagy. In vivo, acetate protects mice from NLRP3 inflammasome-dependent peritonitis and LPS-induced endotoxemia. Collectively, our research demonstrates that acetate regulates the NLRP3 inflammasome via GPR43 and Ca2+-dependent mechanisms, which reveals the mechanism of metabolite-mediated NLRP3 inflammasome attenuation and highlights acetate as a possible therapeutic strategy for NLRP3 inflammasome-related diseases.
DMSO cryopreservation is the method of choice to preserve cells for droplet-based single-cell RNA sequencing
Authors: Wohnhaas Christian T. , Leparc Germán G. , Fernandez-Albert Francesc , Kind David , Gantner Florian , Viollet Coralie , Hildebrandt Tobias , Baum Patrick
Published: July 2019

Combining single-cell RNA sequencing (scRNA-seq) with upstream cell preservation procedures such as cryopreservation or methanol fixation has recently become more common. By separating cell handling and preparation, from downstream library generation, scRNA-seq workflows are more flexible and manageable. However, the inherent transcriptomic changes associated with cell preservation and how they may bias further downstream analysis remain unknown. Here, we present a side-by-side droplet-based scRNA-seq analysis, comparing the gold standard – fresh cells – to three different cell preservation workflows: dimethyl sulfoxide based cryopreservation, methanol fixation and CellCover reagent. Cryopreservation proved to be the most robust protocol, maximizing both cell integrity and low background ambient RNA. Importantly, gene expression profiles from fresh cells correlated most with those of cryopreserved cells. Such similarities were consistently observed across the tested cell lines (R ≥ 0.97), monocyte-derived macrophages (R = 0.97) and immune cells (R = 0.99). In contrast, both methanol fixation and CellCover preservation showed an increased ambient RNA background and an overall lower gene expression correlation to fresh cells. Thus, our results demonstrate the superiority of cryopreservation over other cell preservation methods. We expect our comparative study to provide single-cell omics researchers invaluable support when integrating cell preservation into their scRNA-seq studies.
Inelastic collapse of perfectly inelastic particles
Authors: Topic Nikola , Pöschel Thorsten
Published: July 2019

One of the most intensively discussed subjects in the dynamics of dissipative hard sphere systems is the effect of inelastic collapse, where the entire kinetic energy of the relative motion of a set of particles is dissipated in finite time due to an infinite sequence of collisions. The known collapse scenarios imply two preconditions: inertia of the particles and at least some degree of elasticity. For completely inelastic particles, collapse scenarios degenerate to a single sticky contact. By considering the overdamped motion of a frictional particle along the steepest descent in a rigid landscape, here we show that there exist collapse scenarios of novel type even if neither of these preconditions hold true. By means of numerical simulations we show that such collapses are no rare events due to particular particle shape and/or initial conditions and, thus, may be considered as an alternative scenario of granular cluster formation.
BODIPY-loaded polymer nanoparticles: chemical structure of cargo defines leakage from nanocarrier in living cells
Authors: Trofymchuk Kateryna , Valanciunaite Jurga , Andreiuk Bohdan , Reisch Andreas , Collot Mayeul , Klymchenko Andrey S.
Published: July 2019

Hydrophobicity of a fluorescent cargo loaded into PLGA nanoparticles is crucial for minimizing its leakage in biological media.
A dual fluorescent/phosphorescent zincophosphite with interesting water adsorption and structural transformation properties
Authors: Chen Chuan , Hsieh Chia-Fang , Lin Hsiu-Mei , Hsu Ying-Feng , Yang Jye-Shane , Wang Chih-Min
Published: July 2019

This is a very rare example of a crystalline metallophosphite/phosphate framework with structural transformation, water adsorption, and luminescence color switching (blue to green).
High quantum yield pure blue emission and fast proton conduction from an indium–metal–organic framework
Authors: Zhai Lu , Yu Jing-Wei , Zhang Jin , Zhang Wen-Wei , Wang Lifeng , Ren Xiao-Ming
Published: July 2019

A 3D anionic In3+–MOF integrates the multifunctionality of pure blue luminescence with a high quantum yield of 61.4% and water-mediated fast proton conduction with σ = 2.90–9.22 × 10−3 S cm−1 at 25–60 °C and 99% RH.
tRNA as a stabilizing matrix for fluorescent silver clusters: photophysical properties and IR study
Authors: Sych Tomash S. , Polyanichko Alexander M. , Ramazanov Ruslan R. , Kononov Alexei I.
Published: July 2019

Two types of fluorescent silver clusters can be synthesized on tRNAs: green and red-emitting ones.
The pharmaceutical multi-activity of metallofullerenol invigorates cancer therapy
Authors: Li Jinxia , Chen Linlin , Su Haoran , Yan Liang , Gu Zhanjun , Chen Zhaofang , Zhang Aiping , Zhao Feng , Zhao Yuliang
Published: July 2019

Multi-targeting Gd@C82(OH)22 as a ‘particulate medicine’ against tumours.
Logic gate behavior and intracellular application of a fluorescent molecular switch for the detection of Fe3+ and cascade sensing of F− in pure aqueous media
Authors: Dwivedi Romi , Singh Divya P. , Singh Saumya , Singh Ashish K. , Chauhan Brijesh S. , Srikrishna S. , Singh Vinod P.
Published: July 2019

The nature and coordination sites of a Schiff base 3,3′-(1E,1′E)-(1,3-phenylenebis(azan-1-yl-1-ylidene))bis(methan-1-yl-1-ylidene)dinaphthalen-2-ol (APHN), are tuned by its selective reduction to design a highly efficient fluorescent probe RAPHN.
Trichloroacetonitrile as an efficient activating agent for theipso-hydroxylation of arylboronic acids to phenolic compounds
Authors: Fang Yuanding , Zhao Rong , Yao Yuan , Liu Yang , Chang Denghu , Yao Ming , Shi Lei
Published: July 2019

An efficient and practical method for theipso-hydroxylation of arylboronic acids was developed using TBHP and Cl3CCN under base-free conditions with blue-LED irradiation.
New-fangled sources of cellulose extraction: comparative study of the effectiveness of Cissus latifolia and Ficus benghalensis cellulose as a filler
Authors: Reghunadhan Arunima , Sivan Nayana G. , S. K. Shibina , Mary Siji K. , Koshy Rekha Rose , Datta Janusz , Thomas Sabu
Published: July 2019

Recycled polymers and biopolymers are receiving a great deal of attention these days.
One- and two-photon responsive injectable nano-bundle biomaterials from co-assembled lipopeptides for controlling molecular diffusion
Authors: Wang Dong , Hou Xiaojun , Zhang Xuecheng , Zhao Yurong , Sun Yawei , Wang Jiqian
Published: July 2019

An injectable NB biomaterial.
Pure spin current generated in thermally driven molecular magnetic junctions: a promising mechanism for thermoelectric conversion
Authors: Wu Dan , Cao Xuan-Hao , Chen Shi-Zhang , Tang Li-Ming , Feng Ye-Xin , Chen Ke-Qiu , Zhou Wu-Xing
Published: July 2019

Thermally driven magnetic-molecular junctions can be designed as pure spin current generators, spin thermoelectric devices or thermal-spin converters.
A superparamagnetic Fe3O4–TiO2 composite coating on titanium by micro-arc oxidation for percutaneous implants
Authors: Li Kai , Liu Shiyu , Xue Yang , Zhang Lan , Han Yong
Published: July 2019

The micro-magnetic field induced by the Fe3O4 nanoparticles in TiO2 can efficiently enhance the fibroblast response, reduce bacterial reproduction in vitro, and improve skin integration in vivo.
Molecular engineering of thermally activated delayed fluorescence emitters to concurrently achieve high performance and reduced efficiency roll-off in organic light-emitting diodes
Authors: Li Bowen , Li Zhiyi , Wei Xiaofang , Guo Fengyun , Wang Ying , Zhao Liancheng , Zhang Yong
Published: July 2019

Thermally activated delayed fluorescence (TADF) emitter based organic light-emitting diodes (OLEDs) utilizing both singlet and triplet excitons are considered as the most promising third-generation technology for lighting and display.
Continuous expansion of a synthetic minimal cellular membrane
Authors: Exterkate Marten , Driessen Arnold J.M.
Published: July 2019

A critical aspect of a synthetic minimal cell is expansion of the surrounding boundary layer. This layer should consist of phospholipids (mimics) as these molecules assemble into a bilayer, creating a functional barrier with specific phospholipid species that are essential for membrane related processes. As a first step towards synthetic cells, an in vitro phospholipid biosynthesis pathway has been constructed that utilizes fatty acids as precursors to produce a wide variety of phospholipid species, thereby driving membrane growth. This now needs to be developed further into a sustainable expanding system, meanwhile keeping simplicity in mind. The non-enzymatic synthesis of phospholipid-like molecules forms a realistic alternative for natural enzymatic-based pathways, that nowadays can even support functional membrane proteins. Eventually, coupling to in vitro transcription/translation is required, for which efficient mechanisms of insertion and folding of the involved membrane proteins need to be developed. Such an integrated system will form a suitable foundation of a synthetic minimal cell that eventually can be coupled to other cellular processes such as division.
On adhesion mechanism of salivary pellicle‐PDMS interface
Authors: Ma Genlei , Tang Yue , Zeng Qihang , Zheng Jing
Published: July 2019

The adsorption behaviour of salivary proteins on polydimethylsiloxane (PDMS) surface was investigated here, aiming to fully understand the interfacial adhesion mechanism. Human whole saliva was derived from a healthy donor. Adsorption kinetics of salivary proteins on PDMS surface was examined by quartz crystal microbalance with dissipation (QCM‐D). The morphology and shear energy of the salivary pellicle were characterised using nano‐scratch technique, and its adhesion force was measured by means of atomic force microscopy. Results show that a rough but dense viscoelastic pellicle with a high binding strength is formed on the PDMS surface through the adsorption of salivary proteins. Saliva adsorption obviously increases the PDMS surface wettability but has no influence on its zeta potential. The adhesion force of the pellicle is near zero initially, but it increases significantly with the time. In summary, no electrostatic interaction occurs at the salivary pellicle‐PDMS interface. The bonding of salivary pellicle to PDMS surface is mainly resulted from hydrophobic interaction and is time‐dependent.
Overlapped LT codes over the binary erasure channel: analysis and design
Authors: Hayajneh Khaled F. , Yousefi Shahram
Published: July 2019

Fountain codes are promising forward error correction codes suitable for broadcast and multicast applications where many users with different capabilities are involved in the system. Fixed‐rate codes need a priori information about each channel to decide the best code rate and the code rate is usually chosen according to the worst channel to avoid an outage. Fountain codes are agnostic to the channel conditions and rateless. The rate is realised based on the channel conditions for users separately. Overlapped fountain codes were previously invented over the binary erasure channel to provide more degrees of freedom and better trade‐offs for the rateless‐coded system parameters. In this study, the authors show via analysis and simulations that overlapped fountain codes need fewer decoding steps in comparison with the conventional fountain codes. For example, overlapped fountain codes reduce the number of decoding steps/iterations of belief propagation decoder by even at a source length . They optimise the overlap selection probability of the overlapped fountain codes to maximise the code rate and/or minimise the complexity. At source length, , the proposed analytical and simulation studies show that the highest code rate and lowest average complexity are achieved at an overlap selection probability .
Relevant support recovery algorithm in modulated wideband converter
Authors: Zhu Jiawei , Li Jie , Li Jian , Li Zhi
Published: July 2019

Modulated wideband converter (MWC) is a compressed spectrum sensing system that randomly moves the sparse wideband signal spectrum to the baseband to realise low‐speed sampling. Then, obtaining the effective support which is based on compressed sensing is the most important part for the signal recovery from samples. Aimed at the poor anti‐noise performance of the support recovery, a relevant support recovery algorithm (RSRA) is proposed in modulated wideband converter for spectrum sensing. Specifically, the optimal initial support index is obtained by least squares. Then, the correlation between the measurement matrix column vector corresponding to the adjacent index and the sampling matrix is calculated, and the adjacent index with larger correlation is added to the support. The whole support is acquired by iterative updating under the thought of matching pursuit. Being different from other algorithms, RSRA takes the correlation about adjacent indexes into account, which can weaken the noise interference. Theoretical analysis and numerical simulations show that the proposed scheme can improve the recovery rate of effective support in lower SNR. While improving the anti‐noise capability, other aspects of performance such as channels number and sparsity will not be sacrificed.
Modified relay selection and circuit selection for faster Tor
Authors: Imani Mohsen , Amirabadi Mehrdad , Wright Matthew
Published: July 2019

Users of the Tor anonymity system suffer from less‐than‐ideal performance, in part because circuit building and selection processes are not tuned for speed. In this study, the authors examine both the process of selecting among pre‐built circuits and the process of selecting the path of relays for use in building new circuits to improve performance while maintaining anonymity. First, the authors show that having three pre‐built circuits available allows the Tor client to identify fast circuits and improves median time to first byte (TTFB) by 15% over congestion‐aware routing, the current state‐of‐the‐art method. Second, they propose a new path selection algorithm that includes broad geographic location information together with bandwidth to reduce delays. In shadow simulations, 20% faster median TTFB and 11% faster median total download times over congestion‐aware routing for accessing web page‐sized objects were found. The proposed security evaluations show that this approach leads to better or equal security against a generic relay‐level adversary compared to Tor, but increased vulnerability to targeted attacks. The authors explore this trade‐off and find settings of the proposed system that offers good performance, modestly better security against a generic adversary, and only slightly more vulnerability to a targeted adversary.
Popularity‐aware back‐tracing partition cooperative cache distribution for space–terrestrial integrated networks
Authors: Li Yue , Wang Ye , Yuan Peng , Zhang Qinyu , Yang Zhihua
Published: July 2019

Space‐terrestrial integrated networks consisting of low earth orbit (LEO) satellites andterrestrial users are widely developed for potentially diversified requirementsof content distribution. With an obviously time‐varying topology, however, designing a distribution strategy faces several explicit challenges, such asprolonged content access latency and significant transmission overheads, due tolack of contact opportunities and limited on‐board storage space. In this study, therefore, a novel back‐tracing partition directed on‐path caching distributionmechanism (BPDM) is proposed for the file distribution in the hybrid LEOconstellation and terrestrial network. In the proposed strategy, a group offeasible on‐path cache nodes is iteratively selected by utilising awell‐designed cross‐timeslot graph, as well as a collaborative cached contentplacement strategy, called as multiple regions cooperative cache algorithm, bycarefully considering diversified popularity of target files. As a result, theproposed BPDM could efficiently reduce redundant transmissions of content accessfor different users by fetching objective file mainly from limited quantities ofintermediate caching nodes. Through the simulation results, the proposed methodcan obviously decrease the holistic overheads and access delay compared with theminimum spanning tree algorithm and Network Central Location (NCL) nodeselection metric.
RECV‐MAC: a novel reliable and efficient cooperative MAC protocol for VANETs
Authors: Shahen Shah A.F.M. , Ilhan Haci , Tureli Ufuk
Published: July 2019

In vehicular ad hoc networks (VANETs), mobility among vehicles can result in rapid topology changes with frequent link breakage and unstable communications, which cause collision and packet loss. Conversely, cooperative transmission can improve communication reliability and can enhance communication rate with lower delay by alleviating wireless channel impairments caused by mobility in VANETs. In this study, a novel reliable and efficient cooperative medium access control protocol for VANETs (RECV‐MAC) is proposed. Since a random access mechanism is suitable and efficient because of the dynamic and open nature of VANETs, authors used the random access approach, i.e. carrier sense multiple access with collision avoidance, which is used by IEEE 802.11p. The RECV‐MAC protocol is compatible with IEEE 802.11p. New control messages are introduced to support cooperative communication. The mechanism is defined to choose suitable transmission mode as well as to select optimal helper. To investigate the performance of RECV‐MAC protocol, Markov chain model‐based analytical analysis is provided. The RECV‐MAC protocol is validated by numerical results which demonstrate that RECV‐MAC protocol improves the performance with higher throughput, enhances the reliability of communication by decreasing packet dropping rate (PDR), and decreases delay, in particular, satisfies the delay constraint of 100 ms for sm.
Interference Management and Resource Sharing in Moving Networks
Authors: Jaffry Shan , Hasan Syed Faraz , Gui Xiang
Published: July 2019

Cellular users on‐board vehicles often experience low quality of service (QoS) due to the vehicular penetration loss. Hence, the so‐called mobile‐cells (MCs) have been proposed as a solution. The envisaged MCs will require additional radio resources, which will lead to poor spectral efficiency. This study proposes new methods by which MCs can share the resources of the other links. Firstly, this study presents resource sharing algorithms according to which, MC's access‐link (AL) will share resources either with the backhaul‐link (BL) or with a conventional user. Secondly, it proposes a scheme for controlling AL transmit power to reduce the interference caused to BL while maintaining the QoS for the in‐vehicle users.
Single‐carrier frequency domain equalisation for microwave LOS‐MIMO systems and its performance analysis
Authors: Kamiya Norifumi , Sawahashi Mamoru , Sasaki Eisaku
Published: July 2019

The authors analyse and investigate the effectiveness of frequency domain equalisation (FDE) for single‐carrier (SC) transmission over a line‐of‐sight multiple‐input multiple‐output (LOS‐MIMO) channel with frequency selective fading. For this purpose, they propose a LOS‐MIMO system model employing SC‐FDE techniques together with a data frame structure having a cyclic prefix and postfix (CPP) overhead. The channel capacity of the proposed system is derived taking into account system design parameters, such as symbol rate and roll‐off factor, as well as multipath fading channel parameters. An efficient channel estimation method is also proposed for implementing and simulating the proposed system. Signature curves estimated in simulations are consistent with those expected from the theoretical capacity analysis. The simulation results show that the SC‐FDE approach to the LOS‐MIMO system can, with small CPP overhead, effectively reduce intersymbol and interstream interference.
MAC protocol for indoor optical wireless networks
Authors: Edirisinghe Sampath , Lim Christina , Nirmalathas Ampalavanapillai , Wong Elaine , Ranaweera Chathurika , Wang Ke , Alameh Kamal
Published: July 2019

Optical wireless communication has emerged as a promising candidate for future high data rate indoor applications such as virtual reality. Even though physical layer of optical wireless networks has rapidly developed during last decade, upper layer architecture that harness the physical layer capabilities has not yet been developed in the same pace. To this end, the authors develop a novel contention‐based medium access control (MAC) protocol that accompanies a service differentiation mechanism and a dynamic contention window tuning algorithm. The proposed service differentiation mechanism can identify the diverse traffic types and facilitate their throughput and delay requirements. To add more robustness to the contention‐based MAC protocol which depends on contention windows to avoid collisions, the authors also propose an algorithm that dynamically changes the contention window sizes to suit the congestion level. They analyse the performance of the proposed MAC protocol under diverse network configurations and they show that it is far more effective to use end‐user network metrics such as throughput in dynamic adaptation algorithms in addition to collision rate due to the wide range of traffic types present in the network. The proposed results demonstrate that the proposed MAC protocol can handle next‐generation traffic types and their stringent latency requirements in an effective manner.
Energy‐efficiency‐based CMAC protocol with hybrid time–power splitting relaying for wireless ad‐hoc networks
Authors: Oluwole Akande Damilare , Mohd Salleh Mohd Fadzli
Published: July 2019

This work presents a new cross‐layer cooperative medium access control (CMAC) protocol with hybrid radio frequency (RF) energy‐harvesting (EH) capability to enhance the energy efficiency and network lifetime of energy‐constrained wireless ad‐hoc networks. The proposed protocol employs an adaptive transmission process and integrates the hybrid time–power splitting wireless EH technique at the relay node. The relay node can also assist using its own power (traditional cooperation) provided its battery level is sufficiently adequate and there is no need for RF‐EH. The best transmission mode among direct transmission, cooperative transmission and TPSR cooperation is selected based on power allocation. Two techniques namely the outage probability quality‐of‐service requirement and transmit power optimisation are considered. In addition, the distributed relay selection process is proposed to select the best helper based on location, residual energy and EH information that can significantly enhance the energy efficiency and network lifetime of the wireless network. The results indicate that the proposed protocol can extend the lifetime and improves the energy efficiency of the network.
Probability bounds of cross‐layer interference in femtocell‐underlay cellular networks employing interference alignment
Authors: Ghiamatyoun Alireza , Olfat Ali
Published: July 2019

In a conventional cellular network underlaid with femtocells, the authors employ interference alignment (IA) to restrict cross‐layer co‐channel interference (X‐interference). In their scenario, locally obtained channel state information is allowed to be conveyed between heterogeneous nodes to construct a decentralised IA‐based scheme. Furthermore, they provide closed‐form formulas for the upper bounds of X‐interference in both uplink and downlink directions and characterise how they asymptotically approach zero for big enough channel dimensions used by individual nodes. Simulation results demonstrate that X‐interference is always bounded by the above‐mentioned limits and prove accuracy of their analytical formulas.
Optimal power control and spectrum sensing for throughput maximisation in cognitive radio systems under PUEA
Authors: Karimi Mohammad , Dehghani Ziba , Sadough Seyed Mohammad Sajad , Torabi Mohammad
Published: July 2019

The authors propose an optimal joint power control and multi‐band spectrum sensing scheme for cognitive radio (CR) systems to increase the spectral efficiency and to overcome the spectrum‐sensing errors, in the presence of primary user emulation attacker (PUEA). This optimisation problem is solved to maximise the opportunistic CR data rate under interference and power budget constraints. To solve the formulated optimisation problem, they convert it to a convex problem, and then derive an optimal strategy for joint power control and spectrum access in the considered CR system. They show that the optimal strategy follows a quasi‐underlay signaling, which is equipped with spectrum sensing. They evaluate the performance of the optimised scheme for the CR system in the presence of PUEA, and compare it with the conventional underlay scheme. For more comparison, they compare the proposed approach to that of a similar system, which does not consider the PUEA in the formulation of the joint spectrum sensing and power allocation. They show that the proposed optimal joint power control and spectrum sensing can significantly improve the system performance in terms of average achievable CR data rates compared with the considered conventional methods.
Comprehensive performance analysis of data‐fusion aided cooperative cognitive radio network over η − μ fading channel
Authors: Nallagonda Srinivas , Kumar Godugu Kiran , Nallagonda Ashok Kumar
Published: July 2019

In this paper, analytical performance of efficient soft‐data combining schemes (SDCSs) for cognitive radio network (CRN) is investigated. The performance is investigated in the presence of noise and generalized fading. In more detail, each CRU senses the PU and reports its sensing information to the fusion center (FC). At FC, different SDCSs, which differ in process of fusing the sensing data, are implemented to make the global decision on the status of a PU. In the present work, first the novel mathematical expressions, subject to SDCS and fading are derived. Next, the performance is evaluated through receiver operating characteristics (ROC) and average error rate (AER), considering the significant impact of network and channel parameters. The performance of hard‐decision combining schemes (HDCSs) is also studied for comparison purpose. The analysis presented in this paper eliminates the need of analysis of SDCSs over individual fading channels. An optimal sensing threshold and an optimal number of CRUs where AER attains its minimum value are also determined for all HDCSs and SDCSs. Finally, the derived expressions are validated by computer based simulations for several parameter values of the network.