Blind assessment for stereo images considering binocular characteristics and deep perception map based on deep belief network

© 2018 Elsevier Inc. In recent years, blind image quality assessment in the field of 2D image/video has gained the popularity, but its applications in 3D image/video are to be generalized. In this paper, we propose an effective blind metric evaluating stereo images via deep belief network (DBN). This method is based on wavelet transform with both 2D features from monocular images respectively as image content description and 3D features from a novel depth perception map (DPM) as depth perception description. In particular, the DPM is introduced to quantify longitudinal depth information to align with human stereo visual perception. More specifically, the 2D features are local histogram of oriented gradient (HoG) features from high frequency wavelet coefficients and global statistical features including magnitude, variance and entropy. Meanwhile, the global statistical features from the DPM are characterized as 3D features. Subsequently, considering binocular characteristics, an effective binocular weight model based on multiscale energy estimation of the left and right images is adopted to obtain the content quality. In the training and testing stages, three DBN models for the three types features separately are used to get the final score. Experimental results demonstrate that the proposed stereo image quality evaluation model has high superiority over existing methods and achieve higher consistency with subjective quality assessments

Size-Dependent Phase Map and Phase Transformation Kinetics for Nanometric Iron(III) Oxides (γ → ε → α Pathway)

Nanometric iron­(III) oxide has been of great interest in a wide range of fields due to its magnetic properties, eminent biochemical characteristics, and potential for technological applications. Among iron oxides, ε-Fe₂O₃ is considered as a remarkable phase due to its giant coercive field at room temperature and ferromagnetic resonance capability. Here we present the first size-dependent phase map for ε-Fe₂O₃ via a γ → ε → α pathway together with the activation energies for the phase transformations, based on X-ray powder diffraction (XRD) and high-resolution transmission electron microscopy (HRTEM). HRTEM images of ε-Fe₂O₃ nanocrystals show both inversion and pseudohexagonal twins, which are fundamentally important for understanding the correlation between its nanostructure and magnetic properties. Two activation energies for γ-Fe₂O₃ → α-Fe₂O₃ phase transformations are 186.37 ± 9.89 and 174.58 ± 2.24 kJ mol^–1, respectively. The results provide useful information about the size, crystal structure, and transformation of the nanometric iron oxide polymorphs for applications in areas of developing engineered materials

Natural Indices for the Chemical Hardness/Softness of Metal Cations and Ligands

Quantitative understanding of reactivity and stability for a chemical species is fundamental to chemistry. The concept has undergone many changes and additions throughout the history of chemistry, stemming from the ideas such as Lewis acids and bases. For a given complexing ligand (Lewis base) and a group of isovalent metal cations (Lewis acids), the stability constants of metal–ligand (ML) complexes can simply correlate to the known properties of metal ions [ionic radii (<i>r</i>_M^<i>n</i>+), Gibbs free energy of formation (Δ<i>G</i>°_{f,M^<i>n</i>+}), and solvation energy (Δ<i>G</i>°_{s,M^<i>n</i>+})] by 2.303<i>RT</i> log <i>K</i>_ML = (α*_MLΔ<i>G</i>°_{f,M^<i>n</i>+} – β*_ML<i>r</i>_M^<i>n</i>+ + γ*_MLΔ<i>G</i>°_{s,M^<i>n</i>+} – δ*_ML), where the coefficients (α*_ML, β*_ML, γ*_ML, and intercept δ*_ML) are determined by fitting the equation to the existing experimental data. Coefficients β*_ML and γ*_ML have the same sign and are in a linear relationship through the origin. Gibbs free energies of formation of cations (Δ<i>G</i>°_{f,M^<i>n</i>+}) are found to be natural indices for the softness or hardness of metal cations, with positive values corresponding to soft acids and negative values to hard acids. The coefficient α*_ML is an index for the softness or hardness of a complexing ligand. Proton (H⁺) with the softness index of zero is a unique acid that has strong interactions with both soft and hard bases. The stability energy resulting from the acid–base interactions is determined by the term α*_MLΔ<i>G</i>°_{f,M^<i>n</i>+}; a positive product of α*_ML and Δ<i>G</i>°_{f,M^<i>n</i>+} indicates that the acid–base interaction between the metal cation and the complexing ligand stabilizes the complex. The terms β*_ML<i>r</i>_M^<i>n</i>+ and γ*_MLΔ<i>G</i>°_{s,M^<i>n</i>+}, which are related to ionic radii of metal cations, represent the steric and solvation effects of the cations. The new softness indices proposed here will help to understand the interactions of ligands (Lewis bases) with metal cations (Lewis acids) and provide guidelines for engineering materials with desired chemical reactivity and selectivity. The new correlation can also enhance our ability for predicting the speciation, mobility, and toxicity of heavy metals in the earth environments and biological systems

Fate of fenoxaprop-ethyl and fenoxaprop

Concentration and SD of fenoxaprop-ethyl and fenoxaprop in control and biochar-amended soils during the incubatio

Direct Water Splitting Through Vibrating Piezoelectric Microfibers in Water

We propose a mechanism, a piezoelectrochemical effect for the direct conversion of mechanical energy to chemical energy. This phenomenon is further applied for generating hydrogen and oxygen via direct water decomposition by means of as-synthesized piezoelectric ZnO microfibers and BaTiO₃ microdendrites. Fibers and dendrites are vibrated with ultrasonic waves leading to a strain-induced electric charge development on their surface. With sufficient electric potential, strained piezoelectric fibers (and dendrites) in water triggered the redox reaction of water to produce hydrogen and oxygen gases. ZnO fibers under ultrasonic vibrations showed a stoichiometric ratio of H₂/O₂ (2:1) initial gas production from pure water. This study provides a simple and cost-effective technology for direct water splitting that may generate hydrogen fuels by scavenging energy wastes such as noise or stray vibrations from the environment. This new discovery may have potential implications in solving the challenging energy and environmental issues that we are facing today and in the future

Modeling the Effect of Dissolved Hydrogen Sulfide on Mg²⁺–Water Complex on Dolomite {104} Surfaces

The key kinetic barrier to dolomite formation is related to the surface Mg²⁺–H₂O complex, which hinders binding of surface Mg²⁺ ions to the CO₃^2– ions in solution. It has been proposed that this reaction can be catalyzed by dissolved hydrogen sulfide. To characterize the role of dissolved hydrogen sulfide in the dehydration of surface Mg²⁺ ions, ab initio simulations based on density functional theory (DFT) were carried out to study the thermodynamics of competitive adsorption of hydrogen sulfide and water on dolomite (104) surfaces from solution. We find that water is thermodynamically more stable on the surface with the difference in adsorption energy of −13.6 kJ/mol (in vacuum) and −12.8 kJ/mol (in aqueous solution). However, aqueous hydrogen sulfide adsorbed on the surface increases the Mg²⁺–H₂O distances on the surrounding surface sites. Two possible mechanisms were proposed for the catalytic effects of adsorbed hydrogen sulfide on the anhydrous Ca–Mg carbonate crystallization at low temperature

Cache-enabled in cooperative cognitive radio networks for transmission performance

The proliferation of mobile devices that support the acceleration of data services (especially smartphones) has resulted in a dramatic increase in mobile traffic. Mobile data also increased exponentially, already exceeding the throughput of the backhaul. To improve spectrum utilization and increase mobile network traffic, in combination with content caching, we study the cooperation between primary and secondary networks via content caching. We consider that the secondary base station assists the primary user by pre-caching some popular primary contents. Thus, the secondary base station can obtain more licensed bandwidth to serve its own user. We mainly focus on the time delay from the backhaul link to the secondary base station. First, in terms of the content caching and the transmission strategies, we provide a cooperation scheme to maximize the secondary user's effective data transmission rates under the constraint of the primary users target rate. Then, we investigate the impact of the caching allocation and prove that the formulated problem is a concave problem with regard to the caching capacity allocation for any given power allocation. Furthermore, we obtain the joint caching and power allocation by an effective bisection search algorithm. Finally, our results show that the content caching cooperation scheme can achieve significant performance gain for the primary and secondary systems over the traditional two-hop relay cooperation without caching

Discoidin Domain Receptors Promote α1β1- and α2β1-Integrin Mediated Cell Adhesion to Collagen by Enhancing Integrin Activation

<div><p>The discoidin domain receptors, DDR1 and DDR2, are receptor tyrosine kinases that bind to and are activated by collagens. Similar to collagen-binding β1 integrins, the DDRs bind to specific motifs within the collagen triple helix. However, these two types of collagen receptors recognize distinct collagen sequences. While GVMGFO (O is hydroxyproline) functions as a major DDR binding motif in fibrillar collagens, integrins bind to sequences containing Gxx’GEx”. The DDRs are thought to regulate cell adhesion, but their roles have hitherto only been studied indirectly. In this study we used synthetic triple-helical collagen-derived peptides that incorporate either the DDR-selective GVMGFO motif or integrin-selective motifs, such as GxOGER and GLOGEN, in order to selectively target either type of receptor and resolve their contributions to cell adhesion. Our data using HEK293 cells show that while cell adhesion to collagen I was completely inhibited by anti-integrin blocking antibodies, the DDRs could mediate cell attachment to the GVMGFO motif in an integrin-independent manner. Cell binding to GVMGFO was independent of DDR receptor signalling and occurred with limited cell spreading, indicating that the DDRs do not mediate firm adhesion. However, blocking the interaction of DDR-expressing cells with collagen I via the GVMGFO site diminished cell adhesion, suggesting that the DDRs positively modulate integrin-mediated cell adhesion. Indeed, overexpression of the DDRs or activation of the DDRs by the GVMGFO ligand promoted α1β1 and α2β1 integrin-mediated cell adhesion to medium- and low-affinity integrin ligands without regulating the cell surface expression levels of α1β1 or α2β1. Our data thus demonstrate an adhesion-promoting role of the DDRs, whereby overexpression and/or activation of the DDRs leads to enhanced integrin-mediated cell adhesion as a result of higher integrin activation state.</p> </div

Blocking the interaction with collagen via the GVMGFO site reduces cell adhesion to collagen I in DDR-overexpressing cells.

<p>293-DDR2 cells (A) or 293 empty-vector control cells (B) were pre-incubated with β1-integrin blocking mAb P5D2 (10 µg/ml), high affinity DDR-binding peptide GPRGQOGVNleGFO (GVMGFO at 100 µg/ml) or control peptide GPP (100 µg/ml) for 30 min before seeding onto the indicated substrates. Cell adhesion was then measured after 1 h incubation at 37°C. The data are representative of at least three independent experiments, each performed in triplicate. The error bars indicate the sample standard deviation.</p

Combinations of integrin and DDR ligands support enhanced cell adhesion of 293-DDR cells.

<p>96-well plates were coated with GFOGER or combinations of GMOGER or GAOGER (denoted as GMO and GAO, respectively), GPRGQOGVNleGFO (GVMGFO, denoted as GVM), and GPP, at the indicated ratios. Cells were allowed to adhere for 1 h at 37°C. (A) Cell adhesion to combinations of GMOGER and GVMGFO. (B) Cell adhesion to combinations of GAOGER and GVMGFO. The data are representative of at least four independent experiments, each performed in triplicate. The error bars indicate the sample standard deviation.</p