bluuebunny/crossref_metadata_2025_split huggingface dataset:
A Nanostructured Organic‐Inorganic Hybrid Material: Preparation, Characterization and Catalytic Performance for the Synthesis of N,N′‐Alkylidene Bisamides
Authors: Zare Abdolkarim , Khanivar Roghayyeh , Irannejad‐Gheshlaghchaei Navid , Beyzavi M. Hassan 
Published: April 2019

AbstractIn this research, a novel nanostructured mesoporous organic‐inorganic hybrid material, based on dicationic ionic liquid‐anchored with silica, namely nano‐2‐[N′,N′‐dimethyl‐N′‐(silica‐n‐propyl)ethanaminium chloride]‐N,N‐dimethylaminium bisulfate {nano‐[DSPECDA][HSO4]} has been prepared, and characterized by FT‐IR, energy‐dispersive X‐ray spectroscopy (EDX), field emission scanning electron microscopy (FE‐SEM), X‐ray diffraction (XRD), thermal gravimetry (TG), differential thermal gravimetric (DTG), differential thermal analysis (DTA), and adsorption/desorption porosimetry (BET, Langmuir, adsorption/desorption isotherm, BJH, and t‐plot) methods. Thereafter, the nanomaterial has been utilized as a highly effectual, heterogeneous and recyclable nanocatalyst for the synthesis of N,N′‐alkylidene bisamides via the condensation reaction of arylaldehydes (1 eq.) with primary amides (2 eq.) under solvent‐free conditions. The reaction results were better compared with the literature in terms of two or more of these factors: turnover frequency (TOF), yield, temperature, time, and the reaction media. Moreover, a plausible mechanism for the synthesis has been proposed.
Clay Nanotubes Aligned with Shear Forces for Mesenchymal Stem Cell Patterning
Authors: Zhao Xiujuan , Zhou Changren , Lvov Yuri , Liu Mingxian 
Published: April 2019

AbstractAligned halloysite nanotubes on solid substrates are fabricated by a shearing method with brush assistance. These clay nanotubes are aligned by shear force in strip‐like patterns accomplished with drying ordering at elevated temperatures. The nanotubes' orientation is governed by “coffee‐ring” formation mechanisms depending on the dispersion concentration, nanotube charge, and speed of thermos‐evaporation. Polarized light irradiated through the patterns demonstrates birefringence and confirms the orientation. Scanning electron microscopy and atomic force microscopy show that the nanotubes are aligned along the direction of the wetting lines above 4 wt%, while they are not oriented at lower concentrations. Halloysite concentration, drying temperature, and type of brush fibers affect the pattern ordering. The aligned halloysite systems on glass, tissue culture plates, and polymer films, provide a promising platform for biocell guiding. Human foreskin fibroblasts proliferated well on the aligned clay patterns and the cell orientation agrees with the nanotube direction. Human bone mesenchymal stem cells (HBMSCs) are also cultured on the organized halloysite coating. The clay patterns support HBMSC proliferation with alignment, and such nanostructured substrates promote osteogenesis differentiation without growth factors. This facile method for preparing aligned halloysite patterns on solid substrates is very promising for surface modification in biotissue engineering.
Investigating the Optical Properties of a Laser Induced 3D Self‐Assembled Carbon–Metal Hybrid Structure
Authors: Butt Muhammad Abdullah , Lesina Antonino Calà , Neugebauer Martin , Bauer Thomas , Ramunno Lora , Vaccari Alessandro , Berini Pierre , Petrov Yuriy , Danilov Denis , Manshina Alina , Banzer Peter , Leuchs Gerd 
Published: April 2019

AbstractCarbon‐based and carbon–metal hybrid materials hold great potential for applications in optics and electronics. Here, a novel material made of carbon and gold–silver nanoparticles is discussed, fabricated using a laser‐induced self‐assembly process. This self‐assembled metamaterial manifests itself in the form of cuboids with lateral dimensions on the order of several micrometers and a height of tens to hundreds of nanometers. The carbon atoms are arranged following an orthorhombic unit cell, with alloy nanoparticles intercalated in the crystalline carbon matrix. The optical properties of this metamaterial are analyzed experimentally using a microscopic Müller matrix measurement approach and reveal a high linear birefringence across the visible spectral range. Theoretical modeling based on local‐field theory applied to the carbon matrix links the birefringence to the orthorhombic unit cell, while finite‐difference time‐domain simulations of the metamaterial relates the observed optical response to the distribution of the alloy nanoparticles and the optical density of the carbon matrix.
Reaction Kinetics‐Mediated Control over Silver Nanogap Shells as Surface‐Enhanced Raman Scattering Nanoprobes for Detection of Alzheimer's Disease Biomarkers
Authors: Yang Jin‐Kyoung , Hwang In‐Jun , Cha Myeong Geun , Kim Hye‐In , Yim DaBin , Jeong Dae Hong , Lee Yoon‐Sik , Kim Jong‐Ho 
Published: April 2019

AbstractIt is very challenging to accurately quantify the amounts of amyloid peptides Aβ40 and Aβ42, which are Alzheimer's disease (AD) biomarkers, in blood owing to their low levels. This has driven the development of sensitive and noninvasive sensing methods for the early diagnosis of AD. Here, an approach for the synthesis of Ag nanogap shells (AgNGSs) is reported as surface‐enhanced Raman scattering (SERS) colloidal nanoprobes for the sensitive, selective, and multiplexed detection of Aβ40 and Aβ42 in blood. Raman label chemicals used for SERS signal generation modulate the reaction rate for AgNGSs production through the formation of an Ag‐thiolate lamella structure, enabling the control of nanogaps at one nanometer resolution. The AgNGSs embedded with the Raman label chemicals emit their unique SERS signals with a huge intensity enhancement of up to 107 and long‐term stability. The AgNGS nanoprobes, conjugated with an antibody specific to Aβ40 or Aβ42, are able to detect these AD biomarkers in a multiplexed manner in human serum based on the AgNGS SERS signals. Detection is possible for amounts as low as 0.25 pg mL−1. The AgNGS nanoprobe‐based sandwich assay has a detection dynamic range two orders of magnitude wider than that of a conventional enzyme‐linked immunosorbent assay.
A MXene‐Based Wearable Biosensor System for High‐Performance In Vitro Perspiration Analysis
Authors: Lei Yongjiu , Zhao Wenli , Zhang Yizhou , Jiang Qiu , He Jr‐Hau , Baeumner Antje J. , Wolfbeis Otto S. , Wang Zhong Lin , Salama Khaled N. , Alshareef Husam N. 
Published: April 2019

AbstractWearable electrochemical biosensors for sweat analysis present a promising means for noninvasive biomarker monitoring. However, sweat‐based sensing still poses several challenges, including easy degradation of enzymes and biomaterials with repeated testing, limited detection range and sensitivity of enzyme‐based biosensors caused by oxygen deficiency in sweat, and poor shelf life of sensors using all‐in‐one working electrodes patterned by traditional techniques (e.g., electrodeposition and screen printing). Herein, a stretchable, wearable, and modular multifunctional biosensor is developed, incorporating a novel MXene/Prussian blue (Ti3C2Tx/PB) composite designed for durable and sensitive detection of biomarkers (e.g., glucose and lactate) in sweat. A unique modular design enables a simple exchange of the specific sensing electrode to target the desired analytes. Furthermore, an implemented solid–liquid–air three‐phase interface design leads to superior sensor performance and stability. Typical electrochemical sensitivities of 35.3 µA mm−1 cm−2 for glucose and 11.4 µA mm−1 cm−2 for lactate are achieved using artificial sweat. During in vitro perspiration monitoring of human subjects, the physiochemistry signals (glucose and lactate level) can be measured simultaneously with high sensitivity and good repeatability. This approach represents an important step toward the realization of ultrasensitive enzymatic wearable biosensors for personalized health monitoring.
Using Multistage Design‐Based Methods to Construct Abundance Indices and Uncertainty Measures for Delta Smelt
Authors: Polansky Leo , Mitchell Lara , Newman Ken B. 
Published: April 2019

AbstractPopulation abundance indices and estimates of uncertainty are starting points for many scientific endeavors. However, if the indices are based on data collected by different monitoring programs with possibly different sampling procedures and efficiencies, applying consistent methodology for calculating them can be complicated. Ideally, the methodology will provide indices and associated measures of uncertainty that account for the sample design, the level of sampling effort (e.g., sample size), and the capture or detection probabilities. We develop and demonstrate consistent methodology for multiple monitoring programs that sample different life stages of Delta Smelt Hypomesus transpacificus, a critically endangered fish species endemic to the San Francisco Estuary, whose abundance indices have been at the center of much controversy given the regulatory consequences of their listed status. Current indices use different and incomparable methods, do not account for gear selectivity, and do not provide measures of uncertainty. Using recently available information on gear‐specific, length‐based conditional probabilities of capture given availability, we develop new abundance indices along with measures of uncertainty by means of a single methodological approach. These new indices are highly correlated with existing ones, but the approach taken here illuminates different sources of bias and quantifies between‐year variation using probabilistic statements where the previous indices cannot. Decomposition of uncertainty into its constituent sources reveals that early life stage uncertainty is dominated by gear inefficiency while later life stage uncertainty is dominated by sample size, thus providing guidance for improvements to existing surveys. An additional result of general methodological interest is a demonstration, via simulation intended to reflect realistic data properties, that a lognormal distribution is preferable to the normal distribution for making probabilistic statements about the indices. The work here facilitates the fitting of models attempting to identify factors associated with the dynamics and decline of the species.
An extended actuator cylinder model: Actuator‐in‐actuator cylinder (AC‐squared) model
Authors: De Tavernier Delphine , Ferreira Carlos 
Published: April 2019

AbstractIn this paper, the actuator‐in‐actuator cylinder (AC‐squared) model is presented. This model is an extension of the original actuator cylinder model of Madsen and is capable of modelling the effect of a two concentric actuation surfaces in 2D. The induced velocity at every point in the 2D field is affected by the force field acting on the two actuator cylinders. The equations are derived, and a model verification is performed using analytical solutions of flows, proof of flow equivalence, and using OpenFOAM calculations. Finally, the model is applied to different case studies, and the results are compared with a time‐dependent free wake vortex method.
Influence of blade rotation on the lightning stroke characteristic of a wind turbine
Authors: Wang Yu , Deng Yeqiang , Liu Yilu , Qu Lu , Wen Xishan , Lan Lei , Wang Jian 
Published: April 2019

AbstractThe blades of a wind turbine rotate during normal operation. To investigate the influence of blade rotation on the lightning‐attracting ability of a wind turbine, a discharge test platform is designed for scaled wind turbines. The 50% impulse voltages and flash probabilities of the scaled wind turbines with gap distances of 1 to 8 m in the static and rotary conditions are determined by using the discharge test and selective discharge test. The discharge test for a single wind turbine with a gap of 1 to 2 m indicates that the breakdown voltages of the gap between the scaled turbine and electrodes increases with an increase in the blade rotation speed. However, the discharge test with a gap distance of 4 to 8 m indicates that the breakdown voltage of the fan decreases with an increase in the blade rotation speed. The test results of the scaled dual wind turbines experiment have the same rules. To explain this phenomenon, the influence of wind speed on the space‐charge distribution and electrical field intensity of corona discharge is simulated in the background of a target thundercloud. The rotation of the fan reduces the space‐charge density near the area of the blade tip, which leads to an increase in the field strength near the blade tip of the wind turbine and a decrease in the field strength away from the blade tip. This influence varies in short and long air gap, resulting in opposite relationships between discharge voltage and distance from the tip of the turbine. The results can provide a reference for the lightning protection of wind turbines.
Understanding the Role of α Particles in Oblique Heliospheric Shock Oscillations
Authors: Ofman L. , Koval A. , Wilson L. B. , Szabo A. 
Published: April 2019

AbstractRecent observations by DSCOVR provide high temporal resolution (50 samples per second) magnetic vector field data that allows investigating the details of oblique heliospheric shock oscillations. It was found that some of these shocks exhibit magnetic oscillations, both downstream and upstream of the shock front. The DSCOVR/MAG magnetic field data are supplemented by an extensive database of low Mach number (M < 3) low‐β (<1) shock data observed by Wind albeit with lower temporal resolution. Motivated by the observations, we use the 2.5D hybrid model of the oblique shocks with α particles in addition to kinetic protons and electron fluid. We model the properties of the oblique shocks for a number of typical parameters found in observations and study the effects of the shock parameters and the relative α particle abundances on the properties of the shock magnetic field, density, and velocity oscillations. We find the α particles “surf” on the shock front and produce a wake of density oscillations. We examine the details of the phase space of the ions as well as the ion velocity distribution functions in various parts of the shock and study their nonthermal properties. We determine the effects of the α particle kinetic properties and abundances on the structure and dynamics of the shock downstream oscillations for a range of parameters relevant to low Mach number low‐β heliospheric shocks.
Variability in Trends and Indicators of CO2 Exchange Across Arctic Wetlands
Authors: Coffer Megan M. , Hestir Erin L. 
Published: April 2019

AbstractArctic wetlands store nearly half of the world's soil organic carbon and are crucial to the global carbon cycle. However, most Earth system models fail to account for wetlands given heterogeneity and uncertainty surrounding the response of different wetland types to climate change. We analyzed summer (June–August) carbon dioxide (CO2) exchange, meteorological conditions, and ecological conditions at four Arctic wetlands. Micrometeorological flux tower data were used to assess CO2 exchange and meteorological conditions across 7 to 9 years of data. Climate data were used to assess meteorological conditions across 30 years of data. Satellite data described ecological conditions. Each site acted as a CO2 sink, but strength varied, ranging from −49 to −93 g C/m2 per summer. A trend analysis was used to investigate how CO2 balance and surrounding conditions may have changed. CO2 exchange significantly changed at one site, becoming a stronger sink. Changes in meteorological conditions were variable across sites with the exception of air temperature which, when considering significant trends, unanimously increased across sites. Ecological conditions suggested increased vegetation cover regardless of statistical significance at all sites. A conditional random forest algorithm was used to evaluate drivers of CO2 exchange. Cumulative precipitation and evapotranspiration were the main drivers of net ecosystem exchange and gross primary productivity, while ecosystem respiration was primarily driven by air temperature, suggesting that projected changes in temperature and precipitation patterns will influence the carbon balance of Arctic wetlands. Variability across sites emphasizes the need for long‐term observations across wetland types and climatic gradients.
A Regime Shift From Low to High Sediment Concentrations in a Tide‐Dominated Estuary
Authors: Dijkstra Yoeri M. , Schuttelaars Henk. M. , Schramkowski George P. 
Published: April 2019

AbstractMany estuaries are strongly deepened to improve navigation, with sometimes large and poorly understood consequences to suspended sediment dynamics. To improve understanding of such large changes, we study the Ems River Estuary, where a regime shift from low to high sediment concentrations was observed after deepening. The aim of this study is to improve understanding of the development of the sediment concentration regime over time and estimate the associated time scale. Using the idealized width‐averaged iFlow model, we identify the coexistence of two distinct stable equilibrium regimes representing low and high sediment concentrations, qualitatively matching the regimes observed in the Ems. Depending on the river discharge, a critical depth profile is identified at which the regime shifts. By combining the model results and long‐term observations of the tidal range, first indications of the regime shift are observed around 1989, taking approximately 6–7 years to develop.
Advancements in Hurricane Prediction With NOAA's Next‐Generation Forecast System
Authors: Chen Jan‐Huey , Lin Shian‐Jiann , Magnusson Linus , Bender Morris , Chen Xi , Zhou Linjiong , Xiang Baoqiang , Rees Shannon , Morin Matthew , Harris Lucas 
Published: April 2019

AbstractWe use the fvGFS model developed at the Geophysical Fluid Dynamics Laboratory to demonstrate the potential of the upcoming United States Next‐Generation Global Prediction System for hurricane prediction. The fvGFS retrospective forecasts initialized with the European Centre for Medium‐Range Weather Forecasts (ECMWF) data showed much‐improved track forecasts for the 2017 Atlantic hurricane season compared to the best‐performing ECMWF operational model. The fvGFS greatly improved the ECMWF's poor track forecast for Hurricane Maria (2017). For Hurricane Irma (2017), a well‐predicted case by the ECMWF model, the fvGFS produced even lower five‐day track forecast errors. The fvGFS also showed better intensity prediction than both the United States and the ECMWF operational models, indicating the robustness of its numerical algorithms.
Cortisol administration after extinction in a fear-conditioning paradigm with traumatic film clips prevents return of fear
Authors: Brueckner Alexandra H. , Lass-Hennemann Johanna , Wilhelm Frank H. , Ferreira de Sá Diana S. , Michael Tanja 
Published: April 2019

AbstractCortisol is a stress hormone and potent modulator of learning and memory processes. If administered after learning, cortisol can enhance memory consolidation. Yet it is unknown whether cortisol administration after fear extinction learning strengthens extinction memory. Extinction is a crucial mechanism underlying psychotherapy of posttraumatic stress disorder (PTSD). The present study examined whether extinction can be enhanced by administering cortisol after extinction training. In a registered, randomized, double-blind and placebo controlled trial, 50 healthy participants were exposed to a differential fear-conditioning paradigm with neutral faces as conditioned stimuli (CS) and traumatic film clips as unconditioned stimuli (US). They received either cortisol (n = 25) or placebo (n = 25) immediately after extinction. The cortisol group showed less fear during a return of fear manipulation (reinstatement) evidenced by attenuated fear potentiated startle responses and US-expectancy ratings than the placebo group. Results indicate that cortisol administration after fear extinction strengthens extinction memory and suggest that it might be advantageous to administer cortisol subsequent to successful exposure treatment sessions.
Overexpression of microRNA-301b accelerates hippocampal microglia activation and cognitive impairment in mice with depressive-like behavior through the NF-κB signaling pathway
Authors: Tang Chao-Zhi , Zhang Dong-Fang , Yang Jun-Tang , Liu Qing-Hui , Wang Ya-Ru , Wang Wen-Sheng 
Published: April 2019

AbstractDepression is a condition with a complex etiological pattern, whose effective treatments are highly limited. MicroRNAs (miRNAs) have been investigated in intensive studies owing to their involvement in pathophysiology of mood disorders. The current study aimed to elucidate the role of miR-301b in hippocampus in mouse models of depressive-like behavior. Microarray-based prediction identified the differentially expressed gene neuronal pentraxin II (NPTX2) related to mental depression. Next, the putative miR-301b binding sites on the 3′UTR of NPTX2 were verified. Then the effect of miR-301b on cognitive function of mice with depressive-like behavior was analyzed using the Morris water maze test. In addition, the regulation of miR-301b to NPTX2 and activation of NF-κB signaling pathway was assessed. Following that, the microglia activation and inflammation in hippocampus were evaluated, with the expressions of inflammatory factors being examined. At last, microglia were flow cytometrically sorted and the inflammatory reaction was also assessed in vitro. The obtained findings revealed that miR-301b targeted and negatively regulated NPTX2. Moreover, overexpressed miR-301b activated the NF-κB signaling pathway, as reflected by increasing protein expressions of p-NF-κB. Upregulated miR-301b accelerated cognitive impairment in mice with depressive-like behavior. In addition, overexpression of miR-301b activated microglia and stimulated inflammation in hippocampus, accompanied by enhanced release of tumor necrosis factor-α (TNF-α), interleukin-Iβ (IL-Iβ) and cyclooxygenase-2(COX-2). Taken together, the evidence provided by the current study indicated that overexpression of miR-301b augmented hippocampal microglia activation, thus exacerbating cognitive impairment and inflammation in mice with depressive-like behavior by activating the NF-κB signaling pathway.
FASN activity is important for the initial stages of the induction of senescence
Authors: Fafián-Labora Juan , Carpintero-Fernández Paula , Jordan Samuel James Davison , Shikh-Bahaei Tamanna , Abdullah Sana Mohammad , Mahenthiran Midusa , Rodríguez-Navarro José Antonio , Niklison-Chirou Maria Victoria , O’Loghlen Ana 
Published: April 2019

AbstractSenescent cells accumulate in several tissues during ageing and contribute to several pathological processes such as ageing and cancer. Senescence induction is a complex process not well defined yet and is characterized by a series of molecular changes acquired after an initial growth arrest. We found that fatty acid synthase (FASN) levels increase during the induction of senescence in mouse hepatic stellate cells and human primary fibroblasts. Importantly, we also observed a significant increase in FASN levels during ageing in mouse liver tissues. To probe the central role of FASN in senescence induction, we used a small-molecule inhibitor of FASN activity, C75. We found that C75 treatment prevented the induction of senescence in mouse and human senescent cells. Importantly, C75 also reduced the expression of the signature SASP factors interleukin 1α (IL-1α), IL-1β and IL-6, and suppressed the secretion of small extracellular vesicles. These findings were confirmed using a shRNA targeting FASN. In addition, we find that FASN inhibition induces metabolic changes in senescent cells. Our work underscores the importance of C75 as a pharmacological inhibitor for reducing the impact of senescent cell accumulation.