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Abstract Image restoration is a fundamental problem in computer vision, with the goal of restoring high-quality images from degraded low-quality observation images. However, the ill-posedness of restoration problem often leads to artifacts in the results. It inspires us to study the combination of prior, effectively restrict the solution space and improving the quality of the restored image. In this paper, a novel hybrid regularization method for image restoration is proposed, which adopts both internal and external image priors into a unified framework. Specifically, a new hybrid regularization model is designed. The TV model and a deep image denoiser are inserted into the restoration model using the plug-and-play framework, protecting image details while implicitly using external information for deep denoising. Moreover, in order to make the proposed hybrid regularization operable, an adaptive parameter method is proposed to adaptively balance the TV model and learned model in iteration. Experiments show that the proposed method surpasses the performance of existing image restoration techniques.

Abstract Background The early allopolyploid Brassica napus was a hybrid of two Brassica species, that had undergone a whole genome duplication event followed by genome restructuring, including deletions and small scale duplications. A large number of homologous genes appeared functional divergence during species domestication. Due to the high conservation of de novo glycerolipid biosynthesis, multiple homologues of glycerol-3-phosphate acyltransferases (GPATs) have been found in B. napus. Moreover, the functional variances among these homologous GPAT-encoding genes are unclear. Results In this study, four B. napus homologous genes encoding glycerol-3-phosphate acyltransferase 9 (BnaGPAT9) were characterized. Although a bioinformatics analysis indicated high protein sequence similarity, the homologues demonstrated tissue-specific expression patterns and functional divergence. Yeast genetic complementation assays revealed that BnaGPAT9-A1/C1 homologues but not BnaGPAT9-A10/C9 homologues encoded functional GPAT enzymes. Furthermore, a single nucleotide polymorphism of BnaGPAT9-C1 that occurred during the domestication process was associated with enzyme activity and contributed to the fatty acid composition. The seed-specific expression of BnGPAT9-C1 1124A increased the erucic acid content in the transformant seeds. Conclusions This study revealed that BnaGPAT9 gene homologues evolved into functionally divergent forms with important roles in erucic acid biosynthesis.

Abstract Non-stationary characteristic in nature wind has a great effect on buffeting performance of long-span bridges. The influence of key parameters in non-stationary wind velocity models on nonlinear buffeting responses of a super long-span suspension bridge was investigated in this paper. Firstly, four non-stationary wind velocity models are established by combing the time-varying average wind velocity with an exponential function and the fluctuating wind velocity with four modulation functions, respectively. These non-stationary wind velocity models have obvious non-stationary characteristics and then are validated by the classical power spectrum densities. Finally, three displacement responses of the bridge deck under four different independent variables of β in the exponential function and four modulation functions were compared, respectively. Results show that the turbulence intensities using two non-uniform modulation functions (NMF) are larger than those using uniform modulation functions (uMF). Moreover, the root mean square (RMS) values of three displacement responses increase with the decrease of β. Besides, the RMS values of three displacement under two NMFs are larger than those under two uMFs, and their RMS values under the second uMF are the smallest.

Mullite composite ceramics were fabricated by using mullite powder from waste coal gangue and Al(OH)3 as starting materials. The effects of sintering temperature and Al(OH)3 content on phase composition, microstructure, and mechanical properties of the ceramics were systematically investigated. Results show that the bulk density and flexural strength of composite ceramics increase as the temperature increases from 1480°C to 1560°C. The composite ceramics exhibit optimal performances with addition of 10 wt.% Al(OH)3 at 1560°C, a bulk density of 2.43 g/cm3 and a flexural strength of 124.28 MPa, respectively. Moreover, additional Al(OH)3 promotes a reaction between SiO2 and Al2O3 and forms more mullite phase. The increase in mullite content endows the composite ceramics with high mechanical properties. Scanning electron microscope images indicate that the mullite particles exhibit an interlocking structure, while the corundum phase is “pinned” within the mullite interlocking structure, contributing to the mechanical properties of composite ceramics.

Summary: Nanopore sensing is an emerging technology that has many biosensing applications ranging from DNA sequencing using biological pores to biomolecular analysis using solid-state pores. Solid-state nanopores that are more stable are an attractive choice for biosensing applications. Still, biomolecule interactions with the nanopore surface reduce nanopore stability and increase usage costs. In this study, we investigated the biosensing capability for 102 quartz glass nanopores with a diameter of 11–18 nm that were fabricated using laser-assisted capillary pulling. Nanopores were assembled into multiple microfluidic chips that were repeatedly used for up to 19 weeks. We find that using vacuum storage combined with minimal washing steps improved the number of use cycles for nanopores. The single-molecule biosensing capability over repeated use cycles was demonstrated by quantitative analysis of a DNA carrier designed for detection of short single-stranded DNA oligonucleotides.

Cyclophilins, a type of peptidyl-prolyl cis-trans isomerase, function as important molecular chaperones in a series of biological processes. However, the expression pattern and signal transduction pathway of cyclophilins are still unclear. Here, we showed that the promoter of OsCYP2 could function as a tissue-specific promoter by GUS staining. Moreover, we found that the promoter sequence contained not only core elements but also inducible elements. Then, the ABA-responsive element was used for cDNA library screening, and the transcription factor MYC2-like was identified by a yeast one-hybrid assay and confirmed through an electrophoretic mobility shift assay. Furthermore, the relative expression showed that MYC2-like was induced by abscisic acid. In addition, MYC2-like overexpression enhanced salt tolerance in transformants and partially restored the cyp2-RNAi line. In summary, we explored a novel transcriptional signal mediated by MYC2-like, a potential regulator of salt stress-related physiological processes in rice.

There are still many problems in the stirring dissolution of flocculants: The law of stirring dissolution of flocculants with different molecular weights is not clear, the microstructure of settling floc with different particle sizes of coal slime is still to be explored, and how to apply the law of flocculant dissolution to industrialization? To solve these problems, firstly, mechanical stirring dissolution tests are carried out on anionic polyacrylamide (APAM) with different molecular weights to explore the stirring dissolution law of APAM with 3–25 million molecular weights. Results indicated that the optimal stirring speed of APAM with 3–6 million molecular weight is 800 r/min. The optimal stirring speed of 8–16 million molecular weight APAM is 600 r/min. The optimal stirring speed of 18–25 million molecular weight APAM is 800 r/min. The stirring power formula for APAM dissolution is improved by fitting the experimental data of 3–25 million molecular weight APAM stirring dissolution. Secondly, through APAM performance test, it is verified that the solubility of powdered APAM is the best under optimal solution. Thirdly, through the image measurement and analysis test of settling floc of coal slime, the change law of equivalent diameter of settling floc of different particle sizes of coal slime under the optimal dissolution parameters are explored. Results showed that when the mixing speed is 600 r/min, the equivalent diameter of −0.5 mm slime settling floc is the largest. When the mixing speed is 200 r/min or 400 r/min, the equivalent diameters of 0.5–0.25 mm, 0.25–0.125 mm, 0.125–0.075 mm, 0.075–0.045 mm and −0.045 mm slime settling floc are the largest. The equivalent diameter is positively correlated with the size of slime, and the equivalent diameter of −0.045 mm slime settling floc is the largest. The size of slime is the dominant factor in the change of fractal dimension. The fractal dimension of −0.5 mm slime settling floc is the largest, and the fractal dimension is little affected by mixing speed. Finally, the relationship between the important dissolution parameters of the APAM stirring dissolution test is numerically fitted. In view of the different geometrical parameters of the stirring barrel, a method of deducing the dissolution and stirring time of industrial flocculants is proposed.

The jet flow field is characterized by the dispersion and mixing of multiphase flow, which is widely used in the field of coal slime flotation. In this paper, the behavior of coal slime surface modification, the behavior of material suspension and the effect of different jet fluids on coal slurry blending were studied. Based on the action mechanism of the jet flow field, a jet device suitable for coal slime graded mixing was proposed, and the mixing effect of the jet device was tested. The results show that the jet flow field has strong effects on material dissociation and dispersion, and the mixing effect of a single jet is equivalent to that of the laser particle size analyzer’s own agitation device after stirring for 2.5 min at 500 r/min speed. The SEM test of material surface morphology and the changes of Al and Si elements measured by EDS show that the jet flow field can effectively remove the fine mud wrapped on the surface of coal particles. The precondition of material suspension is to have the just-suspended capacity. The critical jet velocity of coal slime suspension is in the range of 6 m/s~9 m/s. The mixing ability of the jet stream has certain limitations. The increase or decrease of the jet height will cause the decrease of the suspension percentage of sampling points in the tank. The gas jet mode can promote the reagent acting on the surface of the bubble liquid film to form oil bubbles, which is more suitable for hydrophobic mineral flotation. The optimal speed of the gas jet is 0.86 m/s, and the shortest cycle period is 1.0 T (T is one material cycle period). The flotation perfection index of 0.5–0.25 mm and less than 0.075 mm coal slime increased by 2.67% and 26.78%, respectively, indicating that the overall idea of the jet mixing device proposed based on the experimental conclusion is feasible.

The distortion process of kaolinite annealed from 25 °C to 550 °C for different holding times can be characterized using a thermogravimetric/differential scanning calorimeter (TG/DSC) for thermal analysis, X-ray diffraction (XRD) for establishing the crystal structure, the Fourier transform infrared spectrum (FTIR) for identifying the functional groups, and a scanning electron microscope (SEM) for establishing the microstructure. Dehydroxylation is the main reaction during annealing from 25 °C to 550 °C and leads to kaolinite crystal distortion. A stable crystal structure during distortion was obtained by optimizing the bulk phase with quantum chemistry. Then, the crystal structure was studied by using ab initio multiple scattering calculations for X-ray absorption of the fine structure (XAFS). The results of X-ray absorption near the edge structures (XANES) determined that peak shifts and intensity phases slightly increased. The crystal structure distortion of kaolinite during annealing can be explained by the experimental and simulation results. This work provides theoretical support for identifying kaolinite with different degrees of distortion and has the potential for further developments in coal gangue separation.

This paper proposes a fuzzy comprehensive evaluation of ultrafine powders, namely, yield and quality value-based feature selection. Three indicators reflecting product yield and quality were selected to construct a simple and practical fuzzy comprehensive evaluation protocol. The weight set of the indices and the fuzzy evaluation set were calculated based on the analytic hierarchy process (AHP) method. The fuzzy comprehensive evaluation value was worked out as the only comprehensive index for the evaluation of product. The best ultrafine comminution condition will be established through the comparison of the fuzzy comprehensive evaluation values. Single-factor experiments and orthogonal experiments of the main influencing factors of ultrafine comminution were conducted. It was concluded that the importance of each factor is sequentially the concentration, specific surface area (SSA) of the media, and percentage of critical speed (PCS). Moreover, the concentration and SSA of the media were equally important. Ultrafine comminution by ball mill had the best overall performance under the PCS of 85%, the SSA of the media of 0.24 m2/kg, and the concentration of 75%.

Hydrothermal carbon (HTC) was prepared by the one-step hydrothermal method for Cr (VI) removal from wastewater, which was considered a “green chemistry” method. The specific surface area (SBET) of HTC was 85 m2/g with the pore size in range of 2.0–24.0 nm. FT-IR spectra analysis showed that the HTC had abundant chemical surface functional groups. The influence of adsorption parameters such as pH, HTC dosage, Cr (VI) concentration, and contact time on the removal efficiency of Cr (VI) had been investigated. When the initial concentration was 50 mg/L, pH = 6, amount of adsorbent was 0.2 g/50 ml, and adsorption time was 90 min; the Cr (VI) absorbed rate of HTC reached 98%. Batch adsorption experiments indicated that Cr (VI) adsorption data of HTC fitted the Freundlich isothermal and pseudo-second-order kinetic models. Overall, our findings provide a promising material in treatment of Cr (VI)-rich wastewater and give a clear picture of its application, which is worthy of further study.

In this study, a new jet-stirring coupling flotation device that incorporates the advantages of three conventional flotation machines (specifically, Jameson cell, mechanical flotation cell, flotation column) was designed based on jet suction. The suction capacity of a double cosine self-aspirated nozzle utilized by the device was analyzed under different feeding pressures, and the effects of frother concentration, feeding pressure, suction capacity, and height of sampling location on the bubble size distribution (BSD) were investigated using a high-speed video system. It was found that a large amount of air was sucked into the flotation cell by the self-aspirated nozzle arranged in a non-submerged manner, which met the requirements of flotation in terms of the suction amount of air. The suction capacity showed a positive linear correlation with negative pressure inside the nozzle. When the Methyl isobutyl carbinol (MIBC) concentration reached the critical coalescence concentration (CCC), the bubble size stabilized at approximately 0.31 mm, which was smaller than the bubble size produced by the conventional flotation machine. This indicated that bubbles suitable for flotation were generated. D32 linearly decreased with increasing of feeding pressures and conversely increased with increasing suction capacities and sampling location heights, independent of the frother concentration.

Three types of chelating depressants were studied for chalcopyrite/pyrite separation, including S-S, S-O, and O-O types, via density functional theory calculations and microflotation. The calculation results indicate that the depressant's chelating atoms have large coefficient and great activity according to the molecular frontier orbital (HOMO and LUMO) and the orbital coefficients. For S-S type of depressant, S atom in both keto or enol forms won't affect their HOMO and LUMO patterns and the orbital contributions. For S-O type, the presence of N atom in the ring structure of a molecular will increase the reactivity of O-Cu while weak S-Cu. For O-O type, the electron supply capacity of benzene ring is higher than strain chain, and atom N in strain chain increased their electron supply capacity. The microflotation results basically confirmed the prediction based on the calculation. The simulation results demonstrate that the interaction of a depressant with metals and minerals are affected obviously by the spatial structure and electronic structure of an atom in its molecular. [ABSTRACT FROM AUTHOR]

The effects of the dispersants NaOH and Na2CO3 on the classification of coal slimes was studied in a novel classification apparatus. A dispersion effect was characterized through slurry pH and transmittance measurements as well as zeta potential determinations of the slimes. The pH increased and the zeta potential became more negative, while the transmittance decreased with the increase in the NaOH and Na2CO3 addition. The miscellany rates in the overflow decreased by 15.18% and 11.22% with NaOH and Na2CO3, respectively, while that in the underflow was 31.81% and 27.08%, respectively. An ash-removal efficiency from the coal slurries increased by 20.03% and 10.50% with NaOH and Na2CO3, respectively. It was found that the largest difference in classification efficiency between these dispersants in the overflow was 26.05% and underflow was 14.86%. At the high classification efficiency, the transmittance of the slurry decreased, indicating that better dispersion effect led to the higher classification efficiency of the coal slurry. NaOH showed to be a better dispersant for coal slimes classification than Na2CO3 in the novel classification apparatus. [ABSTRACT FROM AUTHOR]

A two-dimensional model of the short-throat-jet flotation machine was developed for studying the flow behaviour and some difficult to measure parameters in the device using computational fluid dynamics (CFD). A laboratorial model was established for verifying the dependability of CFD, while a good agreement between measurement results and simulation was presented. With the inlet pressure set as 0.015 MPa, the minimum pressure close to the wall of the inhale section was obtained as 1200 Pa at Y = 164.2 mm, which was the optimal position for inhaling air. Moreover, the maximum pressure at the cell bottom was about 44,600 Pa at X = 15 mm from the centre of the jet, which was useful in selecting a suitable material to build the cell bottom. Analysis of wall shear stress showed that the wall shear stress on the right side of the jet was larger than that on the left side. Closer to the jet nozzle, the shear stress was larger. The wall shear stress on the right side of the short throat was likewise found to be larger than that on the left side, maximum difference being 140 Pa at Y = 115.5 mm. Analysis of the velocity field showed that the velocity decreased by 50% from the inlet to the outlet of the throat, and seven obvious vortexes were found to exist in the cell, where two of them in the inhale section were advantageous for inhaling air. [ABSTRACT FROM AUTHOR]

A reliability analysis method is proposed in this paper based on the maximum entropy (MaxEnt) principle in which constraints are specified in terms of tire fractional moments instead of integer moments. Then a multiplicative dimensional reduction method (MDRM) is introduced to compute the fractional moments. The method is applicable for both explicit and implicit limit state functions of complex structures. After two examples illustrate tire accuracy and efficiency of this method in comparison to the Monte Carlo simulation (MCS), the method is used to analyze the flutter reliability of suspension bridge. The results show that the empirical formula method in which the limit state function is explicitly represented as a function of variables is only a too conservative estimate for flutter reliability analysis but is not accurate adequately. So it is not suitable for reliability analysis of bridge flutter. The actual flutter reliability analysis should be conducted based on a finite element method in which limit state function is implicitly represented as a function of variables. The proposed M-DRM provide an alternate and efficient way to analyze a much more complicated flutter reliability of long span suspension bridge. [ABSTRACT FROM AUTHOR]

Quick settlement of iron tailings is necessary for the prevention of environmental pollution, meanwhile high concentration is required for the utilization of the sediment. The effect of the flocculant on the settlement of iron tailings with whole size, >45 pm and <45 pm were respectively researched in the terms of settle velocity and sediment concentration. The comparison on the settle efficiencies of different size fraction at the dose of 0.3 and 0.5 ml explained that the flocculant reflects more influence on bridge than viscosity and more influence on ultrafine particles than coarse particles. Different settlement schemes were calculated and compared, the results indicated that pre-classification of the iron tailings is effective for saving flocculant and enhancing the settle efficiency. [ABSTRACT FROM AUTHOR]

The post-flutter state of streamlined steel box girder is studied in this paper. Firstly, the nonlinear aerodynamic self-excited forces of the bridge deck cross section were investigated by CFD dynamic mesh technique and then the nonlinear flutter derivatives were identified on this basis. Secondly, based on the 2-degree-of-freedom (DOF) coupling flutter theory, the torsional amplitude and the nonlinear flutter derivatives were introduced into the traditional direct flutter calculation method, and the original program was improved to the "post-flutter state analysis program" so that it can predict not only the critical flutter velocity but also the movement of the girder in the post-flutter state. Finally, wind tunnel tests were set to verify the method proposed in this paper. The results show that the effect of vertical amplitude on the nonlinear flutter derivatives is negligible, but the torsional amplitude is not; with the increase of wind speed, the post-flutter state of streamlined steel box girder includes four stages, namely, "little amplitude zone", "step amplitude zone", "linearly growing amplitude zone" and "divergence zone"; damping ratio has limited effect on the critical flutter velocity and the steady state response in the post-flutter state; after flutter occurs, the vibration fonn is a single frequency vibration coupled with torsional and vertical DOF. [ABSTRACT FROM AUTHOR]

We proposed a new three-way DNA junction-driven strand displacement mode and fabricated an aptamer-based label-free fluorescent sensing platform on the basis of this mechanism. Assembling the aptamer sequence into the three-way DNA junction makes the platform sensitive to the target of the aptamer. A label-free signal readout method, split G-quadruplex enhanced fluorescence of protoporphyrin IX (PPIX), was used to report the final signal. Here, adenosine triphosphatase (ATP) was taken as a model and detected through this approach, and DNA strand could also be detected by it. The mechanism was investigated by native polyacrylamide gel electrophoresis. Furthermore, on the basis of this molecular platform, we built a logic circuit with ATP and DNA strands as input. Aptamer played an important role in mediating the small molecule ATP to tune the DNA logic gate. Through altering the aptamer sequence, this molecular platform will be sensitive to various stimuli and applied in a wide field. [ABSTRACT FROM AUTHOR]

Endonuclease plays an important role in many biological processes, and an assay of endonuclease activity is of great significance. However, traditional methods for the assay of endonuclease activity have undesirable limitations, such as high cost, DNA-consuming and laboriousness. In the present work, a G-quadruplex-based, fluorescent assay of endonuclease activity has been developed with protoporphyrin IX (PPIX) as a signal reporter. S1 nuclease, a single strand DNA (ssDNA)-specific endonuclease, is employed as model system. In the "on" state, G-quadruplex DNA can greatly enhance the fluorescence of PPIX. However, if S1 nuclease could cleave G-quadruplex DNA into small fragments, there would be no formation of G-quadruplexes, accompanied by low emission response of PPIX. This fluorescent discrimination before or after digestion by nuclease can be used to monitor the activity of S1 nuclease. This assay is simple in design and offers a convenient protocol for homogeneous, rapid and high-throughput detection. In addition, the proposed strategy avoids complicated covalent modifications or chemical labeling, and thus offers advantages of simplicity and cost efficiency. More importantly, K+ is found to well inhibit the activity of S1 nuclease when using certain G-quadruplex DNA as substrate, and thus this system is further used for turn-on detection of K+. S1 nuclease is critical in the detection of K+ since it helps to reduce the background signal. [ABSTRACT FROM AUTHOR]

Photoinduced electron transfer (PET) has been observed for the first time between DNA/Ag fluorescent nanoclusters (NCs) and G-quadruplex/hemin complexes, accompanied by a decrease in the fluorescence of the DNA/Ag NCs. In this PET process, a parallel G-quadruplex and the sensing sequences are blocked by a duplex. The specific combination of targets with the sensing sequence triggers the release of the G-quadruplex and allows it to fold properly and bind hemin to form a stable G-quadruplex/hemin complex. The complex proves favorable for PET because it makes the G-quadruplex bind hemin tightly, which promotes the electron transfer from the DNA/Ag NCs to the hemin FeIII center, thus resulting in a decrease in the fluorescence intensity of the DNA/Ag NCs. This novel PET system enables the specific and versatile detection of target biomolecules such as DNA and ATP with high sensitivity based on the choices of different target sequences. [ABSTRACT FROM AUTHOR]

A label-free bifunctional colorimetric oligonucleotide probe for DNA and protein detection has been developed on the basis of a novel catalytic molecular beacon consisting of two hairpin structures and a split G-quadruplex DNAzyme in the middle. The two loops of this molecular beacon consist of thrombin aptamer sequence and the complementary sequence of target DNA, which are utilized to sense single-stranded DNA and thrombin. The G-quadruplex DNAzyme can effectively catalyze the H2O2-mediated oxidation of 3,3′,5,5′-tetramethylbenzidine sulfate to generate colorimetric signal. Upon addition of the target, the DNA or protein combines with one loop of the hairpin structures, and meanwhile drives the middle G-quadruplex DNAzyme to dissociate. This results in a decrease of catalytic activity, enabling the separate analysis of DNA and thrombin. [ABSTRACT FROM AUTHOR]

In this work, a novel dot-blot DNAzyme-linked aptamer assay (DLAA) for protein detection is developed with thrombin as a model protein. A peroxidase-like DNAzyme which serves as the catalytic label is tethered to a 15-mer thrombin-binding aptamer to form a label-free DNAzyme-linked aptamer probe. Based on specific interaction of the aptamer with target protein immobilized on nitrocellulose membrane, a DNAzyme layer is introduced onto the membrane. The DNAzyme can catalyze the H2O2-mediated oxidation of 3,3′,5,5′-tetramethylbenzidine to produce a colored insoluble product that is apt to be adsorbed onto the nitrocellulose membrane. As a result, blue dots appear on the membrane, in contrast to the colorless background. As the concentration of thrombin increases, the color of dots gets deep. Such a protein concentration-dependent color change can be quantified via an image-processing software, with a detection limit of 0.6 μM. Furthermore, this assay has been applied successfully to the detection of thrombin in biological samples (e.g., human serum), indicating its practicality for bioanalysis. [ABSTRACT FROM AUTHOR]

A molecular aptamer beacon tuned DNA strand displacement reaction was introduced in this work. This strand displacement mode can be used to transform the adenosine triphosphate (ATP) input into a DNA strand output signal for the downstream gates to process. A simple logic circuit was built on the basis of this mechanism. [ABSTRACT FROM AUTHOR]