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A novel green composite flame retardant, bismuth oxychloride nanosheet decorated with chitosan and phytic acid (BiOCl@CS-PA) was prepared in order to improve the fire safety of flexible poly(vinyl chloride) (PVC). Introducing phytic acid (PA) is aimed at promoting the flame retardancy of BiOCl nanosheets in condensed phase using the synergistic effects. Chitosan (CS) not only acts as a bridge between BiOCl and PA, but also increases residue as a charring agent. Adequate characterizations verified that the BiOCl@CS-PA has been prepared successfully. When 3 wt.% of BiOCl@CS-PA was imparted into the PVC matrix, the resultant PVC composite can pass V-0 rating in the UL-94 test. Additionally, cone calorimetry test demonstrated that 3 wt.% of BiOCl@CS-PA reduced the first peak heat release rate and inhibited the pronounced peak heat release rate of PVC matrix between 300–400 s in comparison with the BiOCl nanosheets, indicating a further improvement in flame retardancy of PVC/BiOCl@CS-PA composite with the help of PA in the condensed phase. Microstructure and morphology of the char residue of PVC/BiOCl@CS-PA were analyzed to reveal the flame retardant mechanism. The results indicated that the joint action of PA and CS improves the quality of the char layer, which contributes to improving the flame retardancy in condensed-phase.

A learning-based nonlinear model predictive control (LBNMPC) method is proposed in this paper for general nonlinear systems under system uncertainties and subject to state and input constraints. The proposed LBNMPC strategy decouples the robustness and performance requirements by employing an additional learned model and introducing it into the MPC framework along with the nominal model. The nominal model helps to ensure the closed-loop system’s safety and stability, and the learned model aims to improve the tracking behaviors. As a core of the learned model construction, an online parameter estimator is designed to deal with system uncertainties. This estimation process effectively evaluates both the current and historical effects of uncertainties, leading to superior estimating performance compared with conventional methods. By constructing an invariant terminal constraint set, we prove that the LBNMPC is recursively feasible and robustly asymptotically stable. Numerical verifications for a two-link manipulator are conducted to validate the effectiveness and robustness of the proposed control scheme.

A radical-based asymmetric olefin difunctionalization strategy for rapidly forging all-carbon quaternary stereocenters α to diverse azaarenes is reported. Under cooperative photoredox and chiral Bronsted acid catalysis, cyclopropylamines with α-branched 2-vinylazaarenes can undergo a sequential two-step radical process, furnishing various valuable chiral azaarene-substituted cyclopentanes. The use of the rigid and confined C2-symmetric imidodiphosphoric acid catalysts achieves high enantio- and diastereo-selectivities for these asymmetric [3 + 2] cycloadditions.

Adsorption offers an efficient and eco-friendly method for the recovery of rare earth elements (REEs). However, it is not well known that most adsorbents are not eco-friendly. Rational design of ne...

Well aligned Ti3+, N co-doping TiO2 nanotube array (NTA) film on Ti foil substrate has been successfully prepared by anodic oxidation method using fluoride-based electrolyte in ethylene glycol solution with 3 vol.% H2O, followed by calcination at 400 °C for 2 h. The TiO2 NTA exhibits high UV and visible light absorption capability with a narrow band gap of 2.74 eV, which is attributed to Ti3+ self-doping, probably induced by N doping. The Ti3+ site was found to be 0.46 eV below the conduction band and the N 2p surface state is 1.04 eV above the valence band. Effects of the preparation parameters on tube lengths and diameters of the TiO2 NTAs were investigated based on series of control experiments. The photocatalytic activities of two series of Ti3+, N co-doping TiO2 NTAs with different tube lengths (similar diameter) and different diameters (similar tube length) were assessed by means of photodegradations of rhodamine B (RhB) solutions under simulated sunlight irradiation. The results show that the photocatalytic activity of the Ti3+, N co-doping TiO2 NTA can be enhanced by simply tuning the tube length and diameter in an appropriate range. The photocatalytic reaction mechanism was proposed, based on series of radical-trapping experiments. The results show that ⋅OH is the major active species for photodegradation of RhB.

The coherence attribute has been widely used to detect faults and channels as well as other structural and stratigraphic discontinuities since its introduction. Currently, the most commonly used algorithm for coherence computation is the eigenstructure-based coherence method (C3). When seismic data are of a low signal-to-noise ratio, more traces should be involved in coherence computation to improve the robustness to noise; thus, a larger analysis window shall be used. However, this will lead to increased time costs and blurred coherence images. To address these issues, we have adopted a modified eigenstructure-based coherency algorithm (C3m) based on an inverse distance weighting method and dimensionality reduction of the covariance matrix for eigendecomposition in the case of a large lateral analysis window whose size is larger than [Formula: see text] (nine traces). To further improve the computational efficiency, the add-drop algorithm is also used for covariance matrix construction. In the case of large analysis windows, the time cost by C3m is less than the time cost by C3 as demonstrated in synthetic and field data studies; also, the coherence results computed via C3m are superior to those computed via the traditional C3 method, and the new method is more favorable to seismic interpretation. Thus, our method shall be a potentially efficient and robust alternative to C3 for coherence attribute computation.

The hydrostatic wind turbine (HWT) is a type of wind turbine that uses hydrostatic transmission (HST) drivetrain to replace the traditional gearbox drivetrain. Without the fragile and expensive gearbox and power converters, HWT can potentially reduce the maintenance costs owing to the gearbox and power converter failures in wind power system, especially in offshore cases. We design an MFAC torque controller to regulate the pump torque of the HWT and compared to an H_inf torque controller. Then we design an MFAC pitch controller to stabilise the rotor speed of HWT and compared to a gain-scheduling proportional-integral (PI) controller and a gain-scheduling PI controller with anti-windup (PIAW). The results indicate that MFAC torque controller provides more effective tracking performance than the H_inf controller, and that MFAC pitch controller shows better rotor speed stabilisation performance in comparison with the gain-scheduling PI controller and PIAW.

Passive microwave remote sensing is an effective way to obtain global soil moisture (SM) measurements, and many studies have explored the uncertainty inherent in microwave-based SM products. However, SM product accuracy has not been evaluated in northeast China, a national and global production base for commodity grain. In this study, a ground-based wireless sensor network with 28 observation nodes that were spatially distributed within 36 × 36 km was established to achieve satellite-scale “true” SM values through sensor calibration for specific soil types, senor consistency testing, and spatial scale transformation. The uncertainties of four passive microwave SM products (SMAP L3, SMOS L3, the Japan Aerospace Exploration Agency/JAXA AMSR2, and FY3C) were investigated and the following conclusions were obtained: 1) SMAP SM accuracy was very close to the expected application accuracy of 0.04 cm3/cm3, followed by SMOS, FY3C, and AMSR2; 2) for SMOS and SMAP, there were no significant temporal changes in SM errors, except for the larger error of descending SMOS SM and June SM values for descending SMAP and ascending SMOS. AMSR2 SM generally underestimated field SM, while FY3C SM values under low vegetation conditions were more consistent with field data, with an error of about 0.06 cm3/cm3; 3) agricultural activities and rainfall caused the soil surface roughness to increase or decrease within a growing season, which may have been an important source of satellite-scale SM error indicated by high bias values in July for both SMAP and SMOS; and 4) the standard deviation of field SM (0.06 cm3/cm3) produced a SMAP SM error of about 0.06 cm3/cm3 in low vegetation water content conditions, indicating that SM spatial heterogeneity cannot be ignored in the retrieval algorithm. This article investigated the accuracy and error sources of four satellite SM products in the farmland area of northeast China, and identified future research directions for further improving SM algorithms.

A polyaspartic acid derivative (PASP-Im) as a novel scale inhibitor was synthesized by a simple green synthesis route with polysuccinimide and iminodiacetic acid as the starting materials. The as-synthesized PASP-Im was characterized via nuclear magnetic resonance spectroscopy (1H-NMR) and Fourier transform infrared spectrometry (FT-IR), and its scale inhibition performance was evaluated by a static scale inhibition method. Moreover, scanning electron microscopy, X-ray diffraction, X-ray photoelectron spectroscopy, and density functional theory computational studies were conducted to explore the scale inhibition mechanism of PASP-Im. The findings indicate that the as-synthesized PASP-Im exhibits better antiscale performance against the CaCO3 deposits than the unmodified PASP because of the introduction of iminodiacetic acid group. It also can change the crystallization path of calcium carbonate from stable calcite to vaterite that is dispersible in water, thereby resulting in great changes in the morphology of the CaCO3 scale. Furthermore, the O and N atoms in the negatively charged functional groups (such as –NH2 and –COOH) of PASP-Im can interact with calcium ions to block the active growth point of CaCO3 crystals, which also accounts for the excellent antiscale performance of PASP-Im. With new insights into the synergy between the functional groups of the antiscale molecule and scale-forming ions, this approach would be helpful towards the development of novel high-performance anti-scaling macromolecules.

In this work, a physics-informed deep learning model is developed to achieve the reconstruction of the three-dimensional (3-D) spatiotemporal wind field in front of a wind turbine, by combining the 3-D Navier–Stokes equations and the scanning LIDAR measurements. To the best of the authors’ knowledge, this is for the first time that the full 3-D spatiotemporal wind field reconstruction is achieved based on real-time measurements and flow physics. The proposed method is evaluated using high-fidelity large eddy simulations. The results show that the wind vector field in the whole 3-D domain is predicted very accurately based on only scalar line-of-sight LIDAR measurements at sparse locations. Specifically, at the baseline case, the prediction errors for the streamwise, spanwise and vertical velocity fields are 0 . 263 m/s, 0 . 397 m/s and 0 . 361 m/s, respectively. The prediction errors for the horizontal and vertical direction fields are 2 . 84 ° and 2 . 58 ° which are important in tackling yaw misalignment and turbine tilt control, respectively. Further analysis shows that the 3-D wind features are captured clearly, including the evolutions of flow structures, the wind shear in vertical direction, the blade-level speed variations due to turbine rotation, and the speed variations modulated by the turbulent wind. Also, the developed model achieves short-term wind forecasting without the commonly-used Taylor’s frozen turbulence hypothesis. Furthermore it is very useful in advancing other wind energy research fields e.g. wind turbine control & monitoring, power forecasting, and resource assessments because the 3-D spatiotemporal information is important for them but not available with current sensor and prediction technologies.

Bacterial infection poses great threats to human health and the emergence of drug-resistant bacteria requires effective methods to eliminate bacteria and avoid bacterial resistant. Photodynamic therapy (PDT), which applies photosensitizers (PSs) to generate reactive oxygen species (ROS) under light irradiation, has attracted widespread concern on bacterial treatment, recently. In this work, we develop a far red/near-infrared (FR/NIR)-emissive fluorescent molecule, AIE-TEA, with aggregation-induced emission (AIE) characteristics, for FR/NIR imaging and PDT of bacteria. Due to AIE characteristics and a certain degree of water dispersity, the AIE-TEA can conduct imaging of bacteria without wash process. Moreover, the AIE-TEA can effectively generate ROS under ultralow power white light irradiation (20 mW cm−2) with quantum yield of up to 83%, which is crucial for PDT of bacteria. The AIE-TEA can selectively kill Gram-positive bacteria (S. aureus) via image-guided PDT.

Continuously variable speed wind turbines (CVSWTs) without using fixed speed gearboxes continue being as viable options for modern wind power industry. CVSWTs have an infinite number of transmission ratios in contrast to specific gear ratios of a standard wind turbine. This transmission flexibility allows the generator to maintain a constant speed regardless of highly turbulent wind speeds. The development of CVSWTs has made great progress in recent years due to the high demand for renewable energy sources. Therefore, this paper serves to provide a systematic review of the CVSWTs including mechanical, hydraulic and hydro-mechanical type CVSWTs. The operating principles, design topologies and basic characteristics are described and analyzed. The comparisons and new trends of the CVSWTs are also discussed, which indicate the feasibility of applying CVSWTs in wind power industry and the high potential of using hydro-viscous transmission in megawatt CVSWTs.

A fluorescent compound Tetra(3-[benzoylhydrazone] methyl-4-hydroxyphenyl) ethane (IV) with aggregation-induced emission (AIE) characteristic was synthesized and used as selective light-up probe for sensing of Al3+. Probe IV shows almost no fluorescence without Al3+, which is selectively enhanced with Al3+ by blocking the photo-induced electron transfer (PET) process, and locking the isomerization of C˭N bond and the intramolecular rotation around this C˭N bond. Additionally, it is interesting to observe that IV can facilely self-assemble into discrete nano-leaves with strong fluorescence emission.

In the present work, an attempt has been made for the development of green and high efficiency acid pickling inhibitor based on the eco-friendly polyaspartic acid (PASP). In this view, cysteamine modified PASP (PASP-S) containing S atom was prepared by ring-opening reaction of polysuccinimide with cysteamine. The corrosion inhibition performance of PASP and PASP-S for mild steel in 0.5 M H2SO4 medium were evaluated using weight loss, electrochemical impedance and potentiodynamic polarization methods. The inhibition performance of PASP-S is greatly improved with a high efficiency of 93.9% (weight loss method) at a very low concentration of 100 mg L−1 at 298 K in comparison with unmodified PASP. The obtained results also indicate that PASP-S is a mixed inhibitor and the adsorption of PASP-S on the mild steel surface follows Langmuir adsorption isotherm. Theoretical chemical parameters are calculated using the Density Functional Theory method (DFT). The excellent inhibition performance of PASP-S is due to the presence of pendent functional sulfhydryl group, which can be confirmed by X-ray photoelectron spectroscopy (XPS) analysis of the mild steel samples. The present work provides a simple and effective pathway for synthesizing high efficiency acid pickling inhibitor by introducing a functional group into the PASP chains. Such chemical modification method may also be an effective strategy to improve the efficiency of other polymer acid pickling inhibitors.

At present, synthetic dyes have been widely used in several industries such as textiles, rubber, paper, plastic, and leather tanning. The dyes in effluents are among the most aggressive pollutions ...

Cu3Se2/Cu2Se/Cu2O hollow microspheres with Cu3Se2 as the main component have been synthesized successfully for the first time by a facile sacrificial template method at room temperature, using Cu2O microspheres as the template. The Cu3Se2/Cu2Se/Cu2O product was characterized and its formation mechanism was explored based on series of control experiments. UV–vis diffuse reflectance absorption spectrum and photoluminescence (PL) spectrum were measured to study optical properties of the Cu3Se2/Cu2Se/Cu2O hollow microspheres. The photocatalytic activities were assessed by photodegradations of three organic dye solutions in the presence of a drop of H2O2. The results show that the Cu3Se2/Cu2Se/Cu2O hollow microspheres possess high crystallinity and large ratio of hollow-sphere-diameter: wall-thickness, which can be formed at an optimal reaction condition via a dissolution-recrystallization regime. The Cu3Se2/Cu2Se/Cu2O catalyst exhibits excellent photodegradation activity to a high concentration of methyl blue solution.

We report an enantioselective photoredox dehalogenative protonation as a new type of asymmetric protonation., We report an enantioselective photoredox dehalogenative protonation as a new type of asymmetric protonation. As a paradigm, with a cooperative catalytic system consisting of a chiral H-bonding catalyst and a dicyanopyrazine-derived chromophore (DPZ) photosensitizer that is irradiated with visible light, a range of cyclic and acyclic ketones with labile chiral secondary C–F, C–Cl and C–Br bonds at the α-position were obtained in high yields with good to excellent enantioselectivities (up to >99% ee) by using a secondary amine as the terminal reductant. Given the ready accessibility of halides, the success of this work should provide inspiration for constructing diverse chiral α-tertiary carbonyls and their variants.

Migration is an important factor in the Spatial Prisoners Dilemma Game. An appropriate migration mechanism can improve the level of cooperation in the system. A well-noted mechanism is success-driven migration. However, if individuals migrations are solely driven by payoff, small groups of the individuals may geographically gather into scattered clusters, resulting in the reduction of the cooperation level of the entire population. In this paper, we therefore investigate whether this problem can be resolved by respectively mixing the success-driven migration with two additional migration mechanisms to form two new hybrid migration mechanisms. The first means of hybridization is to mix with the Mean-payoff-driven migration, in which an individual migrates to its first-order neighboring site when its payoff is less than the mean payoff of the whole population. The second means is to mix with the Escaping-defector-driven migration, in which an individual migrates according to the number of defectors among its neighbors. We compare these two hybrid mechanisms with the original migration mechanism that combines the success-driven and random-driven migrations. The simulation results show that the hybrid mechanisms we proposed can effectively eliminate the betrayal clusters and the cooperation level of the system can noticeably be improved. The effect of improving the cooperation level is more significant in case that the initial population is sparse.

An enantioconvergent substitution of 3-substituted 3-chlorooxindoles with N-aryl glycines under visible light irradiation is reported. A transition-metal-free cooperative catalysis platform with a dicyanopyrazine-derived chromophore (DPZ) as a photoredox catalyst and a chiral Brønsted acid catalyst is effective for these transformations, which involve a single-electron transfer redox step and an enantioselective radical coupling. A variety of valuable chiral 3-aminomethylene-3-substituted oxindoles can be directly synthesized with high yields and enantioselectivities.

Geothermal energy is a renewable resource that is constantly available. The low geothermal well operating lifetime is the main challenge in using this type of renewable energy. This problem can be covered by the aid of solar system (hybrid system). For complicated renewable energy systems, finding the optimum design parameters and operating conditions require to develop experimental apparatus or sophisticated thermodynamic models. Hence, in this study, artificial intelligence (AI) approach is proposed for modeling the geothermal organic Rankin cycle (GORC) equipped with solar thermal unit. Indeed, the current study depicts how AI methods can meticulously simulate the operation of a complicated renewable energy system. The developed intelligent methods are adaptive neuro-fuzzy inference system (ANFIS) optimized with particle swarm optimization (PSO) algorithm (ANFIS-PSO) and multilayer perceptron (MLP) neural network optimized with PSO algorithm (MLP-PSO). The models are composed based on the main design parameters of the geothermal system that are solar radiation, well temperature, working fluid mass flow rate, turbine output pressure, surface area of the solar collector and preheater inlet pressure. The intelligent models use the mentioned input variables to predict the net power output, energy efficiency, exergy efficiency and levelized cost of energy (LCOE) of the GORC. Energy, exergy and economic analyses are carried out for the low global warming potential (GWP) refrigerants. It was found out that although the intelligent models can meticulously predict the targets, ANFIS-PSO performs better than MLP-PSO for modeling the GORC with solar system. Root mean square error of this model for prediction of power generation, energy efficiency, exergy efficiency and LCOE was 12.023 (kW), 3.587 × 10 - 4 , 3.278 × 10 - 4 and 1.332 × 10 - 4 , respectively.

The inhibitory effect of radish leaf extract (RLE) on mild steel corrosion in 0.5 M H2SO4 was studied by the weight loss method and the electrochemical method. The results demonstrated that the efficiency of inhibition increased with an increase in the concentration of RLE and decreased with an increase in temperature. The inhibition performance reached 93% with 300 mg L−1 at 298 K. RLE behaved as a mixed-type inhibitor based on the cathode. The inhibition mechanism involved the adsorption of the active ingredients of RLE on the mild steel surface to prevent corrosion. The adsorption followed the Langmuir adsorption isotherm, and physical and chemical adsorption coexisted. The results were supported by SEM, quantum chemical calculations, FTIR and UV-visible spectroscopy analyses.

Seismic sparse spike deconvolution is commonly used to invert for subsurface reflectivity series and is usually implemented as an inversion scheme. Conventional sparse spike deconvolution method does not utilize the relationships among adjacent traces resulting in instability and poor lateral continuity of the inverted result. We propose a multichannel sparse spike deconvolution method with a sparsity-promoting constraint and an extra lateral constraint exploiting the spatial relationships among adjacent seismic traces. Firstly, the dynamic time warping (DTW) is performed between any two adjoining seismic traces to obtain the warping path (a series of estimated time shifts of one seismic trace relative to the other). Based on the assumption that if the inverted reflectivity series is convolved with the same wavelet used for inversion, the newly constructed adjoining seismic traces shall also be conformable to the relationships exploited among the original seismic traces by DTW. A difference operator is constructed with the estimated time shifts to guarantee the difference operation is performed between corresponding time samples on adjoining seismic traces and the inversion is regularized with this difference operator as the lateral constraint. Synthetic and real data case studies confirm that inverted result obtained by the proposed method is superior to those obtained by single-channel sparse spike deconvolution method and another multichannel deconvolution method based on horizontal first-order derivative constraint in both signal-to-noise ratio and lateral continuity.

Phototheranostics represents a promising direction for modern precision medicine, which has recently received considerable attention for cancer research. The ingenious integration of all phototheranostic modalities in a single molecule with precise spatial colocalization is a tremendously challenging task, which mainly arises from the complexity of molecular design and energy dissipation. Reports on a single molecular one-for-all theranostic agent are still very rare. Herein, we designed two novel aggregation-induced emission (AIE)-active fluorogens (AIEgens, named DPMD and TPMD) with a cross-shaped donor-acceptor structure via a facile synthetic method and constructed versatile nanoparticles (NPs) by encapsulating AIEgen with an amphiphilic polymer. The AIEgen TPMD with a twisted structure, high donor-acceptor (D-A) strength, small singlet-triplet energy gap, and abundant intramolecular rotators and vibrators was selected as an ideal candidate for balancing and utilizing the radiative and nonradiative energy dissipations. Notably, TPMD NPs simultaneously possess adequate near-infrared (NIR) fluorescence emission at 821 nm for fluorescence imaging, effective reactive oxygen species generation for photodynamic therapy (PDT), and outstanding photothermal effect for photoacoustic imaging, photothermal imaging, and photothermal therapy (PTT), which demonstrates the superior potential of AIE NPs in multimodal imaging-guided synergistic PDT/PTT therapy.

A novel enantioselective protonation protocol that is triggered by reductive cross coupling of olefins is reported. When under cooperative photoredox and chiral hydrogen-bonding catalytic conditions and using a terminal reductant, various α-branched vinylketones with diverse vinylazaarenes could provide important enantioenriched azaarene derivatives containing tertiary stereocenters at their remote δ-position with high yields and enantioselectivities. This reaction system is also suitable for α-branched vinylazaarenes, thus successfully assembling elusive 1,4-stereocenters. The convenient late-stage modifications of products, especially the formation of remote ε-tertiary and ε-heteroquaternary carbon stereocenters, further highlight the important synthetic value of this method. Control experiments and density functional theory (DFT) calculations were conducted to elucidate the plausible reaction mechanism and origins of regioselectivity and stereoselectivity.

The vortex force map (VFM) method is a promising low-cost technique for predicting unsteady aerodynamic load from the vorticity field. Developed under potential flow assumption and applied to high-resolution computational fluid dynamics (CFD) data, the original VFM method needs to be further explored for viscous flows, especially at low Reynolds numbers and with incomplete knowledge of the flow data. In this paper, the VFM method is extended to general viscous flows, with both forces contributed from vorticity in the flowfield and on the body surface considered. We find that viscosity contributes to not only the skin-friction force but also a pressure force term. We also show that the extended vortex pressure force maps for general flow problems without the potential flow assumption lead to vanishing contributions from the far-field. The extended VFM method is applied to CFD flowfields for the starting flow of a cylinder and a NACA0012 airfoil, and it is used to analyze the force contribution effect of a given vortex. Moreover, acceptable accuracy of the method on truncated domains and under coarse sampling of typical particle image velocimetry measurement size is demonstrated.

We propose to mitigate the barge pitch and roll motions of floating hydrostatic wind turbine (HWT) by combining the advantages of the bidirectional tuned liquid column damper (BTLCD) and the tuned mass damper (TMD). This is achieved by enabling the container of the BTLCD to move freely, connecting it to the main structure through springs and dampers, creating what we call a bidirectional tuned liquid column mass damper (BTLCMD). The BTLCMD is made by the hydraulic reservoir of the HWT, saving costs by avoiding the addition of extra mass and fluids. The HWT simulation model is obtained by replacing the geared drivetrain of the NREL 5-MW barge wind turbine model with a hydrostatic transmission drivetrain. The dynamics of the BTLCMD are then incorporated into the HWT. Two simplified mathematical models, describing the barge pitch and roll motions of the HWT-BTLCMD coupled system, are used to obtain the optimal parameters of the BTLCMD. Simulation results demonstrate that the BTLCMD is very effective in mitigating the barge pitch motion, barge roll motion and the tower base load. The BTLCMD also largely outperforms the BTLCD in suppressing barge motions.

Intrinsically fluorescent poly(amidoamine) dendrimers (IF-PAMAM) are an emerging class of versatile nanoplatforms for in vitro tracking and bio-imaging. However, limited tissue penetration of their fluorescence and interference due to auto-fluorescence arising from biological tissues limit its application in vivo. Herein, a green IF-PAMAM (FGP) dendrimer is reported and its biocompatibility, circulation, biodistribution and potential role for traceable central nervous system (CNS)-targeted delivery in zebrafish is evaluated, exploring various routes of administration. Key features of FGP include visible light excitation (488 nm), high fluorescence signal intensity, superior photostability and low interference from tissue auto-fluorescence. After intravenous injection, FGP shows excellent imaging and tracking performance in zebrafish. Further conjugating FGP with transferrin (FGP-Tf) significantly increases its penetration through the blood-brain barrier (BBB) and prolongs its circulation in the blood stream. When administering through local intratissue microinjection, including intracranial and intrathecal injection in zebrafish, both FGP and FGP-Tf exhibit excellent tissue diffusion and effective cellular uptake in the brain and spinal cord, respectively. This makes FGP/FGP-Tf attractive for in vivo tracing when transporting to the CNS is desired. The work addresses some of the major shortcomings in IF-PAMAM and provides a promising application of these probes in the development of drug delivery in the CNS.

Background The increase in atmospheric CO2 is causing a number of changes in plant growth such as increases in leaf area and number, branching, plant size and biomass, and growth rate. Despite the importance of stomatal responses to CO2, little is known about the genetic and molecular mechanisms that mediate stomatal development and movement in response to CO2 levels. Deciphering the mechanisms that sense changes in CO2 and/or HCO3− concentration is critical for unraveling the role of CO2 in stomatal development movement. In Arabidopsis, CO2-induced stomatal closure is strongly Ca2+-dependent. To further dissect this signaling pathway and identify new components in the CO2 response pathway, we recorded [Ca2+]cyt changes in mutagenized Arabidopsis leaves and screened for mutants with abnormal guard cell behavior in response to CO2/HCO3−. Results We observed that 1 mM HCO3− induces [Ca2+]cys transient changes in guard cells and stomatal closure both in light and darkness. The changes in [Ca2+]cys induced by HCO3− could be detected by an aequorin-based calcium imaging system. Using this system, we identified a number of Arabidopsis mutants defective in both [Ca2+]cyt changes and the stomatal response to CO2/HCO3−. Conclusions We provide a sensitive method for isolating stomatal CO2/HCO3− response genes that function early in stomatal closure and that have a role in regulating [Ca2+]cyt. This method will be helpful in elucidating the Ca2+-dependent regulation of guard cell behavior in response to CO2/HCO3−.

As an important source for large geomagnetic storms, an "ICME-in-sheath" is a completely shocked interplanetary coronal mass ejection (ICME) stuck in the sheath between a shock and host ejecta. Typical characteristics are identified from coordinated multi-sets of observations: (1) it is usually short in duration and lasts a few hours at 1 AU; (2) its solar wind parameters, in particular the magnetic field, seem to keep enhanced for a large range of distances; and (3) common ICME signatures are often lost. The host ejecta could be a single ICME or a complex ejecta, being fast enough to drive a shock. These results clarify previous misinterpretations of this phenomenon as a normal part of a sheath region. The "ICME-in-sheath" phenomenon, together with a preconditioning effect, produced an extreme set of the magnetic field, speed and density near 1 AU in the 2012 July 23 case, all around their upper limits at the same time. This is probably the most extreme solar wind driving at 1 AU and enables us to estimate the plausible upper limit for geomagnetic storm activity. With an appropriate modification in the southward field, we suggest that a geomagnetic storm with a minimum $D_{\rm st}$ of about $-2000$ nT could occur in principle. The magnetopause would be compressed to about 3.3 Earth radii from the Earth's center, well inside the geosynchronous orbit., Comment: Accepted for publication in The Astrophysical Journal Letters

A machine-learning-based surrogate modeling method for distributed fluid systems is proposed in this paper, where a dimensionality reduction technique is used to reduce the flowfield dimension and a regression model is used to predict the reduced coefficients from the input parameters. The surrogate modeling method is specifically designed to tackle the fluid systems involving distributed aerodynamic structures, and its performance is illustrated by the application on the wake flow around wind turbine arrays in an atmospheric boundary layer. The main idea is to first decompose the whole fluid domain into subdomains, then carry out surrogate modeling for each subdomain by treating both the boundary information and the distributed flow parameters as the input parameters, and finally obtain the whole flowfield by combining the flowfield of each subdomain with the consideration of the matching condition at the subdomain interface. The proposed surrogate modeling method is applied to two test cases: a one-dimensional Poisson equation and a high-fidelity wind farm wake model. The results demonstrate the great efficiency and accuracy of the surrogate model and its excellent scalability to distributed systems of different scales.\ud \ud

We investigate the aeroelastic and trajectory control of an high altitude long endurance aircraft model in the presence of gust and turbulence disturbances. The model is derived from geometrically nonlinear beam theory using intrinsic degrees of freedom and linear unsteady aerodynamics, which results in a coupled structural dynamics, aerodynamics, and flight dynamics description. The control design employs a two-loop PI/linear active disturbance rejection control (LADRC) and H $^{\infty }$ control scheme in both the longitudinal and lateral channels, based on a reduced-order linearized model. In each channel, the outer loop (position control) employs a PI/LADRC technique to track the desired flight routes and generate attitude command to the inner loop, while the inner loop (attitude control) uses H $^\infty$ control to track the attitude command generated from the outer loop and computes the control inputs to the corresponding control surfaces. A particle swarm optimization algorithm is employed for parameter optimization of the weighting matrices in the H $^\infty$ control design. The simulation tests conducted on the full-order nonlinear model show that the aeroelastic and trajectory control system achieves good performance with respect to robustness, trajectory tracking, and disturbance rejection.

Soil surface roughness, denoted by the root mean square height (RMSH), and soil moisture (SM) are critical factors that affect the accuracy of quantitative remote sensing research due to their combined influence on spectral reflectance (SR). In regards to this issue, three SM levels and four RMSH levels were artificially designed in this study; a total of 12 plots was used, each plot had a size of 3 m × 3 m. Eight spectral observations were conducted from 14 to 30 October 2017 to investigate the correlation between RMSH, SM, and SR. On this basis, 6 commonly used bands of optical satellite sensors were selected in this study, which are red (675 nm), green (555 nm), blue (485 nm), near infrared (845 nm), shortwave infrared 1 (1600 nm), and shortwave infrared 2 (2200 nm). A negative correlation was found between SR and RMSH, and between SR and SM. The bands with higher coefficient of determination R2 values were selected for stepwise multiple nonlinear regression analysis. Four characterized bands (i.e., blue, green, near infrared, and shortwave infrared 2) were chosen as the independent variables to estimate SM with R2 and root mean square error (RMSE) values equal to 0.62 and 2.6%, respectively. Similarly, the four bands (green, red, near infrared, and shortwave infrared 1) were used to estimate RMSH with R2 and RMSE values equal to 0.48 and 0.69 cm, respectively. These results indicate that the method used is not only suitable for estimating SM but can also be extended to the prediction of RMSH. Finally, the evaluation approach presented in this paper highly restores the real situation of the natural farmland surface on the one hand, and obtains high precision values of SM and RMSH on the other. The method can be further applied to the prediction of farmland SM and RMSH based on satellite and unmanned aerial vehicle (UAV) optical imagery.

With a dual organocatalytic system involving a chiral phosphoric acid and a dicyanopyrazine-derived chromophore (DPZ) photosensitizer and under the irradiation with visible light, an enantioselective Minisci-type addition of α-amino acid-derived redox-active esters (RAEs) to isoquinolines has been developed. A variety of prochiral α-aminoalkyl radicals generated from RAEs were successfully introduced on isoquinolines, providing a range of valuable α-isoquinoline-substituted chiral secondary amines in high yields with good to excellent enantioselectivities.

Evolution of cooperation in prisoner’s dilemma games has been studied extensively in the past decades. Recent studies have investigated the effect of adaptive interaction intensity on spatial prisoner’s dilemma, showing that if individuals can adjust their interaction intensity with each opponent at the same extent, cooperation can be promoted in a proper scale. However, the previous studies about adaptive interaction willingness do not consider the heterogeneity of the opponents. In this paper, a simulative model is developed to examine whether and how the interactive diversity influences cooperation in the spatial prisoner’s dilemma games, in which individuals consider the corresponding behavior of different opponents. The simulation results show that the proposed mechanism can effectively promote cooperation, and the average payoff of the system can significantly be improved by high interaction intensity between cooperators. In addition, we also show four kinds of different individuals to analyze the evolution progresses. The simulations show that cooperators on the boundary decrease their interaction willingness, which makes the boundary defectors lose their opportunity to participate in the interaction and be invaded by cooperators.

An enantioselective cascade aerobic oxidation and semipinacol rearrangement reaction of 2-aryl-3-alkyl-substituted indoles via visible-light-driven cooperative organophotoredox and H-bonding catalysis is reported. The current method provides an expedient and sustainable approach to furnish a variety of valuable chiral 2-aryl-2-alkyl-substituted indolin-3-ones in 64-90 % yield with 58-94 % ee. Preliminary control experiments present important insights into the stereochemistry.

Classic nucleophilic substitution reactions (SN1 and SN2) are not generally amenable to the enantioselective variants that use simple and racemic alkyl halide electrophiles. The merging of transition metal catalysis and radical chemistry with organometallic nucleophiles is a versatile method for addressing this limitation. Here, we report that visible light-driven catalytic asymmetric photoredox radical coupling can act as a complementary and generic strategy for the enantioconvergent formal substitution of alkyl haldies with readily available and bench-stable organic molecules. Single-electron reductive debrominations of racemic α-bromoketones generate achiral alkyl radicals that can participate in asymmetric Csp3–Csp3 bonds forming cross-coupling reactions with α-amino radicals derived from N-aryl amino acids. A wide range of valuable enantiomerically pure β2- and β2,2-amino ketones were obtained in satisfactory yields with good-to-excellent enantioselectivities by using chiral phosphoric acid catalysts to control the stereochemistry and chemoselectivity. Fluoro-hetero-quaternary and full-carbon quaternary stereocenters that are challenging to prepare were successfully constructed., Enantioselective substitution reactions of racemic alkyl halides are inherently limited by the specificity of their stereochemical course (SN1 or SN2). Here, the authors report a radical coupling strategy for the enantioselective aminoalkylation of α-bromoketones for modular, highly enantioselective Csp3−Csp3 bond formation.

Four thermoresponsive silica-poly(N-isopropylacrylamide-co-butyl methacrylate) materials were prepared by grafting (N-isopropylacrylamide-co-butyl methacrylate) at different ratios on multimodal po...

An enantioselective protonation strategy has been successfully applied to the synthesis of chiral α-tertiary azaarenes. With a dual catalytic system involving a chiral phosphoric acid and a dicyanopyrazine-derived chromophore (DPZ) photosensitizer that is mediated by visible light, a variety of α-branched 2-vinylpyridines and 2-vinylquinolines with N-aryl glycines underwent a redox-neutral, radical conjugate addition–protonation process and provided valuable chiral 3-(2-pyridine/quinoline)-3-substituted amines in high yields with good to excellent enantioselectivities (up to >99% ee). An application of this methodology to a two-step synthesis of the enantiomerically pure medicinal compound pheniramine (Avil) is also presented.

The combination of fluorescent (FL) probe and photosensitizer (PS) is a powerful tool for monitoring the changes of specific organelles while studying the photodynamic therapy (PDT) processes at the organelle level. It is very valued for biomedical application but remained challenging due to the lack of ideal FL PDT agent. In this work, an aggregation-induced emission (AIE)-active FL probe (AIE-FR-TPP) by conjugation of a far red/near-infrared (FR/NIR) emitting AIE fluorogen with the mitochondria-targeting group, is reported as a multi-functional fluorophore for mitochondrial imaging and PDT. As for bioimaging, AIE-FR-TPP can selectively light up the cellular mitochondria with low working concentration, short staining time and good biocompatibility. As for PDT, the probe can target mitochondria precisely and generate reactive oxygen species (ROS) efficiently both in living cells and zebrafish embryos. Moreover, AIE-FR-TPP is capable of monitoring the morphological changes of mitochondria based on the AIE effect. These results demonstrate that a real-time visual PDT process at the organelle level in living zebrafish embryos is achieved for the first time by using the AIE PS to induce mitochondrial ROS collapse and report the morphological change on site and in time.

A visible-light-driven sequential photoredox catalysis to allow N-aryl α-amino acids to experience efficient cascade aerobic decarboxylative Povarov and oxidative dehydrogenation (ODH) reactions is described. With a dicyanopyrazine-derived chromophore (DPZ) as a photoredox catalyst in both transformations, two series of valuable azaarenes, i. e., 4-amino tetrahydroquinolines (THQs) and quinolines, were obtained in satisfactory yields featuring diverse 2- and 2,3-substituent patterns. To enable the ODH reaction of 4-amino THQs, a cooperative catalysis with N-hydroxyphthalimide was developed. Additionally, an unprecedented synthesis of chiral N-amino-2-methyl THQs with high enantioselectivities was realized.

The phenomenon of cooperation is prevalent in both nature and human society. In this paper a simulative model is developed to examine how the strategy continuity influences cooperation in the spatial prisoner’s games in which the players migrate through the success-driven migration mechanism. Numerical simulations illustrate that the strategy continuity promotes cooperation at a low rate of migration, while impeding cooperation when the migration rate is higher. The influence of strategy continuity is also dependent on the game types. Through a more dynamic analysis, the different effects of the strategy continuity at low and high rates of migration are explained by the formation, expansion, and extinction of the self-assembled clusters of “partial- cooperators” within the gaming population.

To improve the corrosion inhibition efficiency of eco-friendly polyaspartic acid (PASP) for mild steel in acidic solutions, PASP/N-(3-aminopropyl)imidazole (PD-1) and PASP/N-(3-aminopropyl)-imidazole-co-n-dodecylamine (PD-2) were chemically synthesized by the facile ring-opening reaction of polysuccinimide. Inhibition efficiencies of PD-1 and PD-2 for mild steel in a 0.5 M H2SO4 solution were investigated by electrochemical measurements (electrochemical impedance and polarization) and the weight loss method. In comparison with PASP, PD-1 and PD-2 show improved inhibition efficiencies due to the functional groups. In particular, PD-2 shows superior corrosion inhibition capacity, and the efficiency is up to 94% at a relatively low concentration of 100 mg L−1 at 298 K, as determined by potentiodynamic polarization measurements. Surface analysis of mild steel with PD-2 as an inhibitor clearly indicates that the inhibitor molecules adsorb on the steel surface and efficiently inhibit the corrosion of mild steel. The present work provides very meaningful results in designing and preparing new polymer inhibitors with high inhibition efficiency.

Asymmetric H-bonding catalysis as a viable strategy for enantioselective radical coupling of ketones is demonstrated. With a visible-light-mediated dual catalytic system involving a dicyanopyrazine-derived chromophore (DPZ) photosensitizer and a chiral phosphoric acid (CPA), N-aryl glycines with a variety of 1,2-diketones and isatins underwent a redox-neutral radical coupling process and furnished two series of valuable chiral 1,2-amino tertiary alcohols in high yields with good to excellent enantioselectivities (up to 97% ee). In this catalysis platform, the formation of neutral radical intermediates between ketyl and H-bonding catalyst CPA is responsible for presenting stereocontrolling factors. Its success in this work should provide inspiration for expansion to other readily accessible ketones to react with various radical species, thus leading to a productive approach to access chiral tertiary alcohol derivatives.

In this work, l-tyrosine modified magnetite nanoparticles (TMNPs) are prepared by a facile ultrasound assisted solution route and used for adsorption of both methylene blue (MB) and methyl orange (MO), the typical cationic and anionic dye, respectively. The as-prepared magnetic adsorbents TMNPs are characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Brunauer–Emmett–Teller (BET), Fourier transform infrared (FT-IR), and vibrating sample magnetometer (VSM). The influential factors (solution pH and contact time) to the adsorption of the dyes by the magnetite nanoparticles are investigated. The adsorption kinetics illustrates the suitability of employing the pseudo-second-order kinetic model. Three isothermal adsorption models (Langmuir, Freundlich, and Temkin) are tested to investigate the adsorption properties. The results show that the adsorption behavior fits quite well with the Langmuir model. Thermodynamic parameters (ΔG°, ΔH°, and ΔS°) are estimated and implied that the ads...

The first catalytic asymmetric photoreduction of 1,2-diketones and α-keto ketimines under visible light irradiation is reported. A transition-metal-free synergistic catalysis platform harnessing dicyanopyrazine-derived chromophore (DPZ) as the photoredox catalyst and a non-covalent chiral organocatalyst is effective for these transformations. With the flexible use of a chiral Bronsted acid or base in H+ transfer interchange to control the elusive enantioselective protonation, a variety of chiral α-hydroxy ketones and α-amino ketones were obtained with high yields and enantioselectivities.

The coupling dynamics between a dispersion-managed soliton oscillator and a nonlinear amplifier in an all-photonic crystal fiber-based laser system is emphasized. The intracavity and output pulse evolution dynamics with the dispersion management by a pair of gratings in the oscillator are investigated numerically and experimentally in detail. Then the relationship between the net intracavity dispersion in the oscillator and properties of amplification pulses from the nonlinear amplifier is studied. We find that the best performance in the laser amplification system is significantly dependent on the time-bandwidth product of the seed pulses and the amplifier pump power. As a consequence, the optimized seed output from the DM soliton oscillator for the nonlinear amplifier should be as close to the transform-limited pulse as possible and the intracavity anomalous dispersion should be as large as possible. The narrowest pulse duration of 43 fs without a pedestal and an average power of 28 W, is obtained at a pump power of 60 W. At a pump power of 70 W, 50-fs pulses with a highest output power of 34 W, corresponding to a peak power of 16.2 MW, can also be obtained.

Nitrogen doped indium oxide (InON) and indium tin oxide (ITON) thin films have been fabricated with reactive sputtering in nitrogen-rich plasmas for high temperature thin film thermocouples (TFTCs). Different content of nitrogen was introduced into InON film electrode in order to improve the thermoelectric properties of the thin film thermocouples. XRD, XPS and SEM were used to reveal the chemistry and microstructure of InON films and high temperature static calibration was used to characterize the thermoelectric properties of InON-ITON TFTCs. The relationship between the thermoelectric properties of TFTC and the microstructures of the films was investigated. TFTCs with high linearity and excellent stability were realized.

An unprecedented catalytic asymmetric reaction between azlactones and N-itaconimides has been developed. In the presence of an l-tert-leucine-based urea–tertiary amine Brønsted base catalyst, the tandem conjugate addition–protonation products could be attained in moderate yields with excellent enantio- and diastereoselectivities (up to 99% ee and >20:1 dr). The method provides an efficient approach to access valuable chiral γ-tertiary amine substituted succinimides containing nonadjacent stereocenters.

Four platinum(IV) complexes containing intercalating ligands [1,10-phenanthroline (phen) and 2,2′-bipyridine (bpy)] and ancillary ligands [(1S,2S)-diaminocyclohexane (SS-DACH) and (1R,2R)-diaminocyclohexane (RR-DACH)] were synthesized and characterized by 1H nuclear magnetic resonance, electrospray ionization mass spectrometry, X-ray crystal structure analysis, elemental analysis, ultraviolet absorption spectroscopy, circular dichroism spectroscopy, and electrochemical analysis. The reactions between [Pt(phen)(SS-DACH)Cl2]2+ and glutathione and Ac-CPFC-NH2 were investigated by high-performance liquid chromatography. [Pt(phen)(SS-DACH)Cl2]2+ was reduced to its corresponding Pt(II) complex [Pt(phen)(SS-DACH)]2+, while glutathione and Ac-CPFC-NH2 were oxidized to glutathione-disulfide and a peptide containing an intramolecular disulfide bond, respectively. The cytotoxicities of the Pt(IV) complexes against a human non-small cell lung cancer cell line (A549) and the corresponding cisplatin-resistant cell line (A549cisR) were evaluated. These Pt(IV) complexes showed a higher activity toward A549 and A549cisR than did cisplatin. Also, the cytotoxicities of the Pt(IV) complexes were higher for A549cisR than for A549 cells. Moreover, the cytotoxicities of the (SS-DACH)-liganded platinum complexes were higher than those of the (RR-DACH)-liganded platinum complexes in either A549 or A549cisR cells. Phen-liganded platinum complexes were more cytotoxic than the bpy-liganded platinum complexes. The cytotoxicities of these Pt(IV) complexes had no correlation with reduction potentials.

An enantioselective aerobic decarboxylative Povarov reaction of N-aryl α-amino acids with methylenephthalimidines through cooperative photoredox and chiral Bronsted acid catalysis is reported. With a transition metal-free dual catalytic system including a chiral phosphoric acid and DPZ as a photosensitizer mediated by visible light, the transformations provided a series of valuable chiral isoindolin-1-ones containing a 3,3-spiro-tetrahydroquinoline-based stereocenter in high yields (up to 83%) with good to excellent enantioselectivities (up to 98% ee) and excellent diastereoselectivity (>20 : 1 dr).