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The ability of the brain to generate complex spatiotemporal patterns with specific timings is essential for motor learning and temporal processing. An approach that can model this function, using the spontaneous activity of a random neural network (RNN), is associated with orbital instability. We propose a simple system that learns an arbitrary time series as the linear sum of stable trajectories produced by several small network modules. New finding in computer experiments is that the trajectories of the module outputs are orthogonal to each other. They created a dynamic orthogonal basis acquiring a high representational capacity, which enabled the system to learn the timing of extremely long intervals, such as tens of seconds for a millisecond computation unit, and also the complex time series of Lorenz attractors. This self-sustained system satisfies the stability and orthogonality requirements and thus provides a new neurocomputing framework and perspective for the neural mechanisms of motor learning. [ABSTRACT FROM AUTHOR]

Tough hydrogel adhesives that consist of a robust gel network and can strongly adhere to wet tissues have shown great promise as the next generation of bioadhesives. While a variety of chemistries can be utilized to construct the tough gel network, the covalent conjugation methods for tissue adhesion are still limited. Here we report, for the first time, the use of side product-free amine-thiolactone chemistry which initiates a double crosslinking adhesion mechanism to develop tough gel adhesives. Thiolactone groups can conjugate with tissue-surface amines via a ring-opening reaction. The resultant thiol end groups can be further crosslinked into disulfide linkages, enabling the formation of a robust and stable adhesion layer. The thiolactone-bearing tough hydrogel composed of methacrylate-modified gelatin, acrylic acid, and thiolacone acrylamide exhibited good biocompatibility and mechanical properties, and strong adhesion to various types of engineering solids and tissues. We also demonstrated its ability to function as a tissue sealant and drug depot. The novel adhesion mechanism will diversify future design of bioadhesives for hemostasis, drug delivery, tissue repair, and other applications. Tough hydrogel adhesives with excellent tissue-adhesive and mechanical properties have demonstrated tremendous promise for hemostasis, tissue repair, and drug delivery applications. However, the covalent chemistry for tissue adhesion has been limited, which narrows the choice of materials for the design of bioadhesives and may pose a safety concern. Here, for the first time, we report the use of side product-free amine-thiolactone chemistry, which involves a double crosslinking adhesion mechanism, for developing tough hydrogel adhesives. We demonstrate that thiolactone-bearing tough hydrogels exhibit favorable biocompatibility and mechanical properties, and superior adhesion to both engineering solids and tissues. Our new adhesion technology will greatly facilitate future development of advanced bioadhesives for numerous biomedical applications. [Display omitted] [ABSTRACT FROM AUTHOR]

Forecasting solar irradiance is of utmost importance in supplying renewable energy efficiently and timely. This paper aims to experiment five variants of recurrent neural networks (RNN), and develop effective and reliable 5-minute short term solar irradiance prediction models. The 5 RNN classes are long–short term memory (LSTM), gated recurrent unit (GRU), Simple RNN, bidirectional LSTM (Bi-LSTM), and bidirectional GRU (Bi-GRU); the first 3 classes are unidirectional and the last two are bidirectional RNN models. The 26 months data under consideration, exhibits extremely volatile weather conditions in Jinju city, South Korea. Therefore, after different experimental processes, 5 hyper-parameters were selected for each model cautiously. In each model, different levels of depth and width were tested; moreover, a 9-fold cross validation was applied to distinguish them against high variability in the seasonal time-series dataset. Generally the deeper architectures of the aforementioned models had significant outcomes; meanwhile, the Bi-LSTM and Bi-GRU provided more accurate predictions as compared to the unidirectional ones. The Bi-GRU model provided the lowest RMSE and highest R2 values of 46.1 and 0.958; additionally, it required 5.25*10−5 seconds per trainable parameter per epoch, the lowest incurred computational cost among the mentioned models. All 5 models performed differently over the four seasons in the 9-fold cross validation test. On average, the bidirectional RNNs and the simple RNN model showed high robustness with less data and high temporal data variability; although, the stronger architectures of the bidirectional models, deems their results more reliable. • Forecasting solar irradiance is important in efficiently supplying renewable energy. • Five variants of RNN models were developed to predict short term solar irradiance. • The RNN models performed differently in the 9-fold cross validation test. • Bidirectional RNN models provided better predictions than the Unidirectional ones. [ABSTRACT FROM AUTHOR]

Abstract Cortical neural connectivity has been shown to exhibit a small-world (SW) network topology. However, the role of the topology in neural information processing remains unclear. In this study, we investigated the learning performance of an echo state network (ESN) that includes the SW topology as a reservoir. To elucidate the potential of the SW topology, we limited the numbers of the input and output nodes in the ESN and spatially segregated the output nodes from the input nodes. We tested the ESNs in two benchmark tasks: memory capacity and nonlinear time-series prediction. The SW-ESN exhibited the best learning performance when the spectral radius of the weight matrix was large and when the input and output nodes were segregated. That is, the SW topology provided the ESN with a stable echo state property over a broad range of the weight matrix and efficiently propagated input signals to the output nodes. This result is the same as that of the ESN using a real human cortical connectivity. Thus, the results suggest that the SW topology is essential for maintaining the echo state property, which is the appropriate neural dynamics between input and output brain regions. [ABSTRACT FROM AUTHOR]

In the field of exposure science, various exposure assessment models have been developed to complement experimental measurements; however, few studies have been published on their validity. This study compares the estimated inhaled aerosol doses of several inhalation exposure models to experimental measurements of aerosols released from consumer spray products, and then compares deposited doses within different parts of the human respiratory tract according to deposition models. Exposure models, including the European Center for Ecotoxicology of Chemicals Targeted Risk Assessment (ECETOC TRA), the Consumer Exposure Model (CEM), SprayExpo, ConsExpo Web and ConsExpo Nano, were used to estimate the inhaled dose under various exposure scenarios, and modeled and experimental estimates were compared. The deposited dose in different respiratory regions was estimated using the International Commission on Radiological Protection model and multiple-path particle dosimetry models under the assumption of polydispersed particles. The modeled estimates of the inhaled doses were accurate in the short term, i.e., within 10 min of the initial spraying, with a differences from experimental estimates ranging from 0 to 73% among the models. However, the estimates for long-term exposure, i.e., exposure times of several hours, deviated significantly from the experimental estimates in the absence of ventilation. The differences between the experimental and modeled estimates of particle number and surface area were constant over time under ventilated conditions. ConsExpo Nano, as a nano-scale model, showed stable estimates of short-term exposure, with a difference from the experimental estimates of less than 60% for all metrics. The deposited particle estimates were similar among the deposition models, particularly in the nanoparticle range for the head airway and alveolar regions. In conclusion, the results showed that the inhalation exposure models tested in this study are suitable for estimating short-term aerosol exposure (within half an hour), but not for estimating long-term exposure. [ABSTRACT FROM AUTHOR]

Sensitivity analysis plays an important role in geoscientific computer experiments, whether for forecasting, data assimilation or model calibration. In this paper we focus on an extension of a method of regionalized sensitivity analysis (RSA) to applications typical in the Earth Sciences. Such applications involve the building of large complex spatial models, the application of computationally extensive forward modeling codes and the integration of heterogeneous sources of model uncertainty. The aim of this paper is to be practical: 1) provide a Matlab code, 2) provide novel visualization methods to aid users in getting a better understanding in the sensitivity 3) provide a method based on kernel principal component analysis (KPCA) and self-organizing maps (SOM) to account for spatial uncertainty typical in Earth Science applications and 4) provide an illustration on a real field case where the above mentioned complexities present themselves. We present methods that extend the original RSA method in several ways. First we present the calculation of conditional effects, defined as the sensitivity of a parameter given a level of another parameters. Second, we show how this conditional effect can be used to choose nominal values or ranges to fix insensitive parameters aiming to minimally affect uncertainty in the response. Third, we develop a method based on KPCA and SOM to assign a rank to spatial models in order to calculate the sensitivity on spatial variability in the models. A large oil/gas reservoir case is used as illustration of these ideas. [ABSTRACT FROM AUTHOR]

Prostaglandins (PGs) are recognized as important immune regulators. Using human follicular dendritic cell (FDC)-like HK cells, we have investigated the immunoregulatory role of PGs and their production mechanisms. The present study was aimed at determining the role of TGF-β in IL-1β-induced cyclooxygenase-2 (COX-2) expression by immunoblotting. COX-2 is the key enzyme responsible for PG production in HK cells. TGF-β, when added simultaneously with IL-1β, gave rise to an additive effect on COX-2 expression in a dose-dependent manner. However, TGF-β inhibited IL-1β-stimulated COX-2 expression when it was added at least 12 h before IL-1β addition. The inhibitory effect of TGF-β was specific to IL-1β-induced COX-2 expression in HK cells. The stimulating and inhibitory effects of TGF-β were reproduced in IL-1β-stimulated PG production. Based on our previous results of the essential requirement of ERK and p38 MAPKs in TGF-β-induced COX-2 expression, we examined whether the differential activation of these MAPKs would underlie the opposing activities of TGF-β. The phosphorylation of ERK and p38 MAPKs was indeed enhanced or suppressed by the simultaneous treatment or pre-treatment, respectively. These results suggest that TGF-β exerts opposing effects on IL-1β-induced COX-2 expression in HK cells by differentially regulating activation of ERK and p38 MAPKs. [ABSTRACT FROM AUTHOR]

Abstract: Volatile organic compounds (VOCs) are potentially harmful air pollutants that are commonly encountered in urban environments. Various chemicals known to produce VOCs are used in laboratory fume hoods; however little research has been done to show the effect of such chemicals and associated VOCs on the local air quality. This study aims to assess the concentration of various VOCs emitted from the exhaust stacks of rooftop fume hoods mounted on laboratory buildings, as well as to determine factors that contribute to different concentrations of commonly encountered VOCs. A total of six university campus buildings, comprising four laboratory buildings and two non-laboratory buildings as controls, were selected as case studies. VOCs were sampled using activated charcoal tubes in front of fume hood exhausts located on the rooftops of buildings and were analyzed GC/FID. Factors such as meteorological conditions and the amount of chemicals utilized in the building of interest were investigated. A total of 11 individual compounds were quantified in the samples collected. The concentrations of 11 VOCs at laboratory buildings were significantly higher (GM; 184.74 μg/m3, GSD; 3.38) than those of non-laboratory buildings (GM; 12.1 μg/m3, GSD; 1.64, p < 0.001). The concentrations of 10 individual compounds emitted from laboratory buildings were significantly higher than those emitted from non-laboratory buildings (p < 0.001) with the exception of m- and p-xylene (p = 0.155). We found that the amount of chemical use was the predominant factor determining the composition and concentrations of VOCs found (p < 0.001). From this study, we suggest that installation of an air purification system in fume hood ventilation systems is necessary to prevent atmospheric pollution and adverse health effects in university populations, as well as supporting efforts towards creating ‘green campus’ environments. [Copyright &y& Elsevier]

Pulse electric field induced electron emission from the Pb(Zr0.65Ti0.35)O3 ferroelectric films has been investigated as a function of the film thickness from 0.2 to 4.0 μm and the upper electrode diameter from 200 to 1100 μm. The electron emission charge from the 3.0 μm film was several nC per pulse, which was comparable to that of the bulk ferroelectrics. However, the local dielectric breakdown occurred in the films below 1.0 μm without the electron emission, which was confirmed by the optical microscopy observation after the emission tests. As the upper electrode size decreased and the film thickness increased, electrons were more easily emitted without breakdown. [ABSTRACT FROM AUTHOR]

Direct forecasting has recently been proposed as a method for uncertainty quantification in non-linear inverse problems. The method directly forecasts a desired future response without the need for full model inversion. The method has been successfully applied to a range of subsurface field cases, such as groundwater, shallow and deep geothermal and oil/gas predictions. In this paper, we extend the framework of direct forecasting to do what it was avoided to do in the first place: model inversion. The idea is simple: replace the prediction variables with the model variables. Two challenges now occur: the model dimensions, in subsurface realm at least, are much higher than data variables. This is the case in the paper where we consider dynamic data and high-dimensional spatial models for geological structure and properties. Secondly, the regression applied in the original method, being a linear regression of prediction variables on transformed data, is unlikely to lead to models that match field observations. We address these challenges first by adding a variable selection method (through global sensitivity analysis) for the model space. More specifically, we select those model components that are most sensitive to data variables only. The linear assumption is mitigated by a sequential updating of sensitive model variables. We illustrate our method on a Libyan oil reservoir with complex geological uncertainty involving structural, petrophysical and fluid model parameters. • A method for joint inversion of both global and spatial parameters. • Extension of direct forecasting to directly invert model variables. • Application to a real field oil reservoir in Libya. [ABSTRACT FROM AUTHOR]

• We characterized the behavior of airborne particles produced by spray products. • Propellant-type products generally created more particles than hand-pressure type. • FS-SEM analysis confirmed the aggregation of nano-sized particles for all products. • Deposition loss rates of smaller particles depended on their initial concentration. • The loss rate of larger particles was regardless of initial concentration. Commercial spray products are commonly used in daily life and airborne particles generated by these products may cause adverse health effects. Our study was aimed to characterize the behaviors of airborne particles from spray products and to determine the deposition loss rate. Four categories of spray products with highly frequent use - air fresheners, fabric deodorants, window cleaners, and a bathroom cleaner - were selected for the study. The products were applied in a cleanroom according to the instructions for use. Airborne particles (10–10,000 nm) were measured within the breathing zone of a user with a scanning mobility particle sizer and an optical particle spectrometer. Additionally, filter sampling was performed to examine the morphological characteristics of the particles using a field emission-scanning electron microscope (FE-SEM). The initial concentration and particle size distribution varied among different spray types and products. Two propellant-type air fresheners that we tested showed a high initial concentration of smaller sized particles. However, one of these and all hand-pressure type propellants showed a low initial concentration in all size ranges. We observed that particles in nucleation mode (10–31.6 nm) decreased and aggregated particles shifted to accumulation mode (100–1,000 nm) over time. The FS-SEM analysis confirmed the aggregation of nano-sized particles for all products. The deposition loss rates of various particle sizes depended on the initial concentration and distribution of particle sizes. For two air fresheners with high initial concentrations, the loss rate of small-sized particles was higher than that of the other products whereas the particle loss rate of large-sized particles was higher, regardless of initial concentration. The results of this study can give us useful information in the behaviors of airborne particles in the consumer spray products and resulting exposure assessment especially in the application to the exposure modeling of spray products. [ABSTRACT FROM AUTHOR]

We report a low magnetic loss Ba 3 Co 2 Fe 24 O 41 (Co 2 Z) hexaferrite for use in gigahertz (GHz) antennas. Acid-etching was very effective in removal of unwanted Y-type hexaferrite (Ba 2 Co 2 Fe 12 O 22 ) from calcined Co 2 Z powder. It is found that the calcined and acid etched (AE) Co 2 Z hexaferrite shows a low magnetic loss tangent (tan δ μ ) of 0.012 and 0.037 at 1 and 2 GHz, respectively. These low tan δ μ are attributed to removal of Y-type hexaferrite, which possesses a lower anisotropy field ( H k ) than W-type hexaferrite (BaCo 2 Fe 16 O 27 ). The figure of merit (FOM) of the AE Co 2 Z hexaferrite is 141.7 and 48.7 at 1 and 2 GHz, respectively. These FOM are much higher than the FOM of previously reported low-loss magnetic materials. Therefore, the AE Co 2 Z hexaferrite can be a good candidate for GHz antenna application in the ultra-high frequency (UHF) band. [ABSTRACT FROM AUTHOR]

Silica fume and nano-silica have been widely investigated to hold the significant potential in enhancing the properties of alkali-activated slag (AAS) systems, however, discrimination of the respective role in such systems requires a clear elucidation. Multiple combinations of silica fume and nano-silica were incorporated into the AAS paste samples in an attempt to discriminate the respective influence of silica fume and nano-silica on the properties of AAS paste samples. The samples with nano-silica showed higher initial heat evolution compared to silica fume, yet no secondary acceleration heat evolution peak was observed. This feature resulted in the lower strength development at the early stages in the samples with nano-silica compared to those containing silica fume. The incorporation of nano-silica led to a lower pore size distribution than silica fume at 28 d of curing, contributing to the development of higher strength at later curing stages. Both the degree of Si polymerization and Al crosslinking in calcium aluminosilicate hydrate (C-A-S-H) increased by the incorporation of siliceous materials, with the incorporation of nano-silica further intensifying this effect. This work provided insights into the effects of incorporating silica fume and nano-silica into AAS systems from a microstructural perspective in which its novelty lies in offering visions into property modifications of AAS, shedding light on how each additive influences the properties. • N ano-silica induced the highest initial heat evolution without subsequent peak s. • N ano-silica led to a lower pore size distribution than silica fume at later stage s. • Nano-silica enhanced the degree of Si polymerization and Al crosslinking in C-A-S-H. • N ano-silica led to higher strength at later stages compared to silica fume. [ABSTRACT FROM AUTHOR]

The structural changes in (100 − x)Na0.5Bi0.5TiO3–xBaTiO3 (0 ≤ x ≤ 10) ceramics were investigated as a function of composition and temperature by X-ray diffraction and Raman spectroscopy. As Ba concentration increases, the structure changed from rhombohedral to tetragonal (x ≥ 6.5) across a morphotropic phase boundary like phase coexistence at x ∼ 5.5, which is further evidenced by phonon anomalies observed in composition-dependent Raman spectra. On heating, the disappearance of peak splits in {111} (x ≤ 5) and {200} (x ≥ 6.5) Bragg peaks and the changes in their 2θ-positions indicated temperature-driven structural changes: ferroelectric to antiferroelectric (≈T d, depolarization temperature) at 220 °C and antiferroelectric to paraelectric (rhombohedral to tetragonal) at 320 °C. In addition, Raman spectral analysis suggested that at elevated temperatures, two tetragonal phases with slightly different space groups coexisted at x ≥ 6.5 and most of the phase transition temperatures shifted towards left with increasing x. [ABSTRACT FROM AUTHOR]

High density sintered Sm(Fe 0.8 Co 0.2) 11 Ti bulk magnets were successfully produced using a newly developed high pressure pressing fabrication method. The purity of the hard magnetic ThMn 12 phase in the bulk magnet reached to higher than 97 wt.%. The phase transformation behavior from amorphous to ThMn 12 phase during heat treatment was systematically investigated by transmission electron microscopy. The remanent magnetization and maximum energy product of a bulk magnet were 96.0 emu/g and 12.22 MGOe, respectively. To the best of our knowledge, the achieved maximum energy product is the highest among all the SmFe 12 -based bulk magnets reported. Image, graphical abstract [ABSTRACT FROM AUTHOR]

Due to its location in a politically and militarily sensitive area as a maritime demarcation between North and South Korea, increasing attention has been given to the chemical and physical changes in atmospheric aerosols on Baengnyeong Island. To observe modifications in the concentrations and components of basic air pollutants, a Korean State Air Quality Monitoring Superstation was established on the island. The monitoring data obtained from the superstation revealed a significant, short-lived increase in mass concentration of SO 2 , NO 2 , and nitrate, organic carbon, and heavy metals (especially Pb) in ambient PM 2.5 , as well as a gradual decrease in mass concentration of PM 10 , PM 2.5 , and sulfate in PM 2.5 during September 24–27, 2012. Building upon this data, we conducted source appointment of PM 2.5 using the positive matrix factorization receptor model (PMF) and identified six major sources: sea-spray aerosols (29.8%), mobile and biogenic aerosols (24.3%), secondary aerosols (20.0%), gunshot residue (11.1%), mineral dust (8.6%), and oil combustion (6.3%). To examine the physicochemical properties of atmospheric particles, 16 samples collected during that period were investigated using a quantitative energy-dispersive electron probe X-ray microanalysis (ED-EPMA). We analyzed the morphology, mixing state, elemental constituents, and relative elemental atomic concentrations of 2545 individual particles from the aforementioned six sources, with a focus on particles containing Ca, organic carbon, and Pb. The complementary use of PMF and ED-EPMA confirmed that an episode of air pollution, likely resulting from a military exercise or activity, occurred from September 25 to 26 on or near Baengnyeong Island, leading to an increase in aerosols from gunshot residue and oil combustion. The significant increase in the relative number abundance of organic carbon and heavy metal-containing particles precisely matched their mass concentrations from the monitoring data. These findings imply that multiple methods for bulk and single-particle analysis are necessary when addressing important issues related to source appointment of atmospheric particulate matter. • An episodic increase in organic carbon and heavy metal-containing fine particles was observed on Baengnyeong Island. • The ion ratios of NO 3 −/SO 4 2− and NH 4 +/SO 4 2− experienced a noteworthy rise concurrently with elevation of organic carbon. • Ambient fine particles likely from gunshot residue and oil combustion on Baengnyeong Island were identified. • Quantitative ED-EPMA could be well complementary to PMF analysis for source appointment of atmospheric particles. [ABSTRACT FROM AUTHOR]

The temperature for phase transformation of ε → τ in Mn 54 Al 46 C x (hereafter denoted by MnAlC x , x  = 0–5) alloys was systematically studied by using the traditional thermal analysis method and a more precise magnetic measurement method developed in this work. The effect of carbon content and cold-rolling on the magnetic properties of the MnAlC x alloys was studied. The onset temperature of massive growth of τ- from ε-phase increases with increasing carbon content in MnAlC x . The carbon content has little effect on the onset temperature of displacive growth of ε → τ but has substantial effect on the displacive growth rate at certain temperature. Pure τ-MnAlC x with varied x was obtained by annealing the ε-phase at optimum temperatures determined by our method. The Curie temperature of the MnAlC x decreases significantly first and then increases slightly with increasing carbon content. The coercivity and the remanent magnetization of the as-prepared τ-MnAlC x increase with increasing x first and become stable at x  > 3 and x  > 4, respectively. A cold-rolling method was introduced in this work to enhance the magnetic properties of τ-MnAlC x . The coercivity and remanent magnetization of the τ-MnAl after cold-rolling were enhanced up to 4.3 times and 3.3 times, respectively. The coercivity of the cold-rolled τ-MnAlC x decreases with increasing x and becomes stable when x  > 2. The remanent magnetization and saturation magnetization of the cold-rolled τ-MnAlC x vary little with x . [ABSTRACT FROM AUTHOR]

Substantial mitigation of air pollutants emissions has been performed since 2013 around Beijing, and changes in the atmospheric characteristics have been expected over the downstream area of Beijing. In this study, both WRF-Chem simulation and on-site measurements were utilized for the Baengnyeong (island) supersite, one of the representative regional background sites located in the Yellow Sea, the entrance area of the long-range transport process in Korea. The changes in the chemical compositions of inorganic aerosols were examined for spring-time during the Chinese emission mitigation period from 2014 to 2016. The measured ratio of ionic species to PM 2.5 at the Baengnyeong supersite showed changes in aerosol inorganic chemical compositions from sulfate in 2014 to nitrate in 2015–2016. The modeling results also showed that nitrate was low in 2014 and significantly increased in 2015 and 2016, and the acidic aerosol condition had also changed toward a more neutralized status in both the simulation and the observations. The WRF-Chem modeling study further indicated that the sulfur was not neutralized in 2014. However, in 2015 and 2016, SO 2 was more sufficiently neutralized as sulfur emissions were substantially reduced in China, while at the same time nitrate had begun to increase in such a 'SO 2 –poor' condition in Beijing area in China, and thus approaching more enhanced neutralization over the Yellow Sea area. The causes of the higher nitrate based on the modeled characteristics of the ammonia-sulfate-nitrate aerosol formation in response to the SO 2 emissions reduction in China are also discussed in this paper. Inorganic composition is changing from sulfate to nitrate, and aerosol acidity is approaching more enhanced neutralization over regional background area in Northeast Asia. Unlabelled Image • Inorganic components were examined over background area during Beijing's emission reduction. • Observations showed significant change in decreased sulfate and opposite trend in nitrate. • Aerosol acidity changed to enhanced nitrate neutralization through the emission reduction period. • More enhanced nitrate was also simulated by WRF-Chem mainly due to Beijing's emission mitigation. [ABSTRACT FROM AUTHOR]