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In recent years, with the development of remote sensing technology and the enhancement of the value of remote sensing images in military and civil fields, remote sensing image object segmentation has also received more and more attention. This paper mainly studies the application of instance segmentation based on deep convolutional neural network in the remote sensing image. This paper proposes an attention balanced feature pyramid module, which strengthens multi-level features and uses the attention module to suppress the interference features of noise in the complex background. In addiction, Soft-NMS is introduced to improve the performance of the network, and GIoU loss is introduced to improve the effect of object detection. The proposed network improves the average detection and segmentation accuracy (mAP) values from 4 1. 7 5 % and 3 5. 3 4 % to 4 3. 0 5 % and 3 6. 0 2 % , respectively. [ABSTRACT FROM AUTHOR]

The high-pressure leakage of underground pipeline could entrain the nearby sands and soils, and thus cause the jet fire of gas-solid mixtures. In addition, the thermal runaway of Lithium ion batteries could also cause a typical gas-solid jet diffusion flame. In comparison with the gaseous jet diffusion flame and the gas-solid-air jet premixed flame, the gas-solid jet diffusion flame lacks of exploration. Thus, a new facility consisting of a jet fire apparatus and a sand feeder, was designed to explore the gas-solid jet fire. The test repeatability was justified for the proposed facility. The dynamical differences of gas-solid and gaseous jet fires are clarified. It is found that the gas-solid jet fire holds a larger lift-off height, a less visible flame height and a less radiative fraction than the purely gaseous jet fire. In particular, for gas-solid jet fires at high exit velocities, the lift-off height increases, but the visible flame height and radiative fraction seem to decrease, as the particle size of sand decreases to increase the jet height of sand. (1) Inside the flame volume, the sand plays a role of heat sink to decrease the flame temperature and thus the flame burning velocity. Moreover, in the lift-off region, the sand dilutes the gas fuel and isolates the surrounding oxygen to inhibit the combustion. Both effects of sand cause a large lift-off height, especially for the sand of little particle size. (2) A large lift-off height means the increase of the air mass entrained from flame base or the portion of the premixed flame to the whole flame. In addition, the sand particle-laden flow would significantly increase the ambient air entrainment rate of fire plume. Both effects result in a less visible flame height. (3) The portion of the premixed flame increases in the bottom, which reduces the total soot amount inside the whole flame volume. The decrease of the flame temperature and the total soot amount reduces the radiative fraction. (4) The sand significantly affects the flame geometry and radiative fraction, which alters the radiant heat flux distribution and challenges the development of thermal radiation model for gas-solid jet fires. The gas-solid jet fire holds a less peak radiant heat flux but a higher positon of peak radiant heat flux than the gaseous jet fire. In addition, the line source radiation model available in literature is revised to well predict the radiant heat flux distribution of the gas-solid jet fires. [ABSTRACT FROM AUTHOR]

Image-to-image translation techniques have been used in many different fields and have obtained remarkable performance in recent years. However, in many image-to-image translation tasks, only certain parts of the image need to be converted instead of the whole image. Traditional GAN-based methods often reconstruct the entire image, which may lead to artifacts and low-quality results. To address this issue, we propose a novel model, named GiGAN: Gate in GAN, which utilizes special Residual Blocks embedded with Gate Cells to filter and extract the features for facial attribute transfer and facial expression synthesis tasks. Specifically, we treat the intermediate feature from source domain to target domain as a sequence, and introduce the gate mechanism into this sequential task. To achieve this, we introduce the convolutional layers into gate cell and modify the stream in traditional gate cell to suit for image-to-image translation task. We designed two types of methods based on reusing parameters in the residual blocks or not, namely GiGAN-reuse and GiGAN-non-reuse. Experimental results and quantitative evaluations show that our model has superior performance against state-of-the-arts. And ablation studies demonstrate the effectiveness of our method. Furthermore, visualization of the features in Gate Cells shows that Gate Mechanism can filter the features in image-to-image translation effectively. [ABSTRACT FROM AUTHOR]

Multimodal image-to-image translation is a challenging topic in computer vision. In image-to-image translation, an image is translated from a source domain to different target domains. For many translation tasks, the difference between the source image and the target image is only in the foreground. In this paper, we propose a novel deep-learning-based method for image-to-image translation. Our method, named URCA-GAN, is based on a generative adversarial network and it can generate images of higher quality and diversity than existing methods. We introduce Upsample Residual Channel-wise Attention Blocks (URCABs), based on ResNet and softmax channel-wise attention, to extract features associated with the foreground. The URCABs form a parallel architecture module named Upsample Residual Channel-wise Attention Module (URCAM) to merge features from the URCABs. URCAM is embedded after the decoder in the generator to regulate image generation. Experimental results and quantitative evaluations showed that our model has better performance than current state-of-the-art methods in both quality and diversity. Especially, the LPIPS, PSNR, and SSIM of URCA-GAN on CelebA dataset increase by 1.31 % , 1.66 % , and 4.74 % respectively, the PSNR and SSIM on RaFD dataset increase by 1.35 % and 6.71 % respectively. In addition, visualization of the features from URCABs demonstrates that our model puts emphasis on the foreground features. [ABSTRACT FROM AUTHOR]

Recognition of micro-expressions remains a topic of concern considering its brief span and low intensity. This issue is addressed through convolutional neural networks (CNNs) by developing multi-task learning (MTL) method to effectively leverage a side task: gender detection. A dual-stream multi-task framework called GEME is introduced that recognises micro-expressions by incorporating unique gender characteristics and subsequently improves the micro-expression recognition accuracy. This research aims to examine how gender differences influence the way micro-expressions are displayed. The current study proves that selecting relevant features of micro-expressions distinctive to the gender and added to the micro-expression features improves the micro-expression recognition accuracy. This network learns gender-specific features and micro-expression features and adds them together to learn the combination of shared and task-specific representations. A multi-class focal loss is used to mitigate the class imbalance issue by down-weighing the easy samples and concentrate more on misclassified samples. The Class-Balanced (CB) focal loss is also implemented for a better class balancing during Leave-One-Subject-Out (LOSO) validations where CB loss re-balances and re-weights the loss. The experimental results on three widely used databases demonstrate the improved performance of the proposed network and achieve comparable results with the state-of-the-art methods. [ABSTRACT FROM AUTHOR]

• Functional polyester with zinc is designed and synthesized. • The constructed polyester could recognize the cell membrane of bacteria. • The functional polyester could inhibit the cell wall synthesis. • Caging UDP kills bacteria without detectable resistance. The increasing spread of antimicrobial resistance results in untreatable infections, causing thousands of deaths. Thus, it is urgent to find new antibiotics that kill the causative pathogen via a novel action mechanism without detectable resistance. The pyrophosphate structures of UDP-MurNAc-pentapeptide, lipid I, and lipid II in bacteria cytoplasm are highly conserved but play a key role in bacterial wall synthesis and is a promising target for antibiotics. However, to date, no attempt to target pyrophosphate has been made to kill bacteria. Here, we found that a synthetic cage, denoted as PZn2020, can tightly cage pyrophosphate structures blocking transport of lipid and the biosynthesis of cell wall to kill bacteria. It exhibits sub-μg activity against all gram-negative and gram-positive bacteria tested and avoids detectable resistance with low host toxicity. Such a caging pyrophosphate strategy suggests a path towards developing antibiotics with a new mechanism that is likely to avoid the development of resistance. [ABSTRACT FROM AUTHOR]

Heavy nitrogen (N) application to gain higher yield of wheat (Triticum aestivum L.) resulted in increased production cost and environment pollution. How to diminish the N supply without losing yield and/or quality remains a challenge. To meet the challenge, we integrated and expressed a tobacco nitrate reductase gene (NR) in transgenic wheat. The 35S-NR gene was transferred into two winter cultivars, “Nongda146” and “Jimai6358”, by Agrobacterium-mediation. Over-expression of the transgene remarkably enhanced T1 foliar NR activity and significantly augmented T2 seed protein content and 1000-grain weight in 63.8% and 68.1% of T1 offspring (total 67 individuals analyzed), respectively. Our results suggest that constitutive expression of foreign nitrate reductase gene(s) in wheat might improve nitrogen use efficiency and thus make it possible to increase seed protein content and weight without augmenting N supplying. [ABSTRACT FROM AUTHOR]

Providing access to diverse polymer structures is highly desirable, which helps to explore new polymer materials. Poly(thioester sulfonamide)s, combining both the advantages of thioesters and amides, however, are rarely available in polymer chemistry. Here, the ring‐opening copolymerization (ROCOP) of cyclic thioanhydride with N‐sulfonyl aziridine using mild phosphazene base, resulting in well‐defined poly(thioester sulfonamide)s with highly alternative structures, high yields, and controlled molecular weights, is reported. Additionally, benefiting from the mild catalytic process, this ROCOP can be combined with ROCOP of N‐sulfonyl aziridines with cyclic anhydrides to produce novel block copolymers. [ABSTRACT FROM AUTHOR]

Mitochondrial malfunction is considered to be a decisive signal of apoptosis. It would be a promising strategy to target mitochondria in cancer cells to generate reactive oxygen species (ROS), thus directly inducing mitochondrial damage. We herein reported a mitochondria-targeted, photo-responsive polymer (Mito-PNBE), which can self-assemble into nanoparticles (Fe–CO@Mito-PNBE) encapsulated with diphenylcyclopropenone (light-responsive CO prodrugs) and aminoferrocene-based prodrugs via hydrophobic interactions. Upon UV-irradiation, the rapid release of CO and aminoferrocene-based prodrugs caused by disassembly was observed. On one hand, the released carbon monoxide in mitochondria could enhance ROS generation and accelerate oxidative metabolism. On the other hand, the aminoferrocene-based prodrugs will release Fe3+/Fe2+ ions in the tumor microenvironment, thus triggering the Fenton reaction, which generates more ROS and damages the mitochondria. Thus, the synergistic effect of the two drugs produces enough amounts of ROS in the mitochondria, leading to mitochondrial collapse with an enhanced cancer therapeutic effect. This multifunctional platform has potential in precision cancer therapy. [ABSTRACT FROM AUTHOR]

Multiblock copolymers are envisioned as promising materials with enhanced properties and functionality compared with their diblock/triblock counterparts. However, the current approaches can construct multiblock copolymers with a limited number of blocks but tedious procedures. Here, we report a thioester‐relayed in‐chain cascade copolymerization strategy for the easy preparation of multiblock copolymers with on‐demand blocks, in which thioester groups with on‐demand numbers are built in the polymer backbone by controlled/living polymerizations. These thioester groups further serve as the in‐chain initiating centers to trigger the acyl group transfer ring‐opening polymerization of episulfides independently and concurrently to extend the polymer backbone into multiblock structures. The compositions, number of blocks, and block degree of polymerization can be easily regulated. This strategy can offer easy access to a library of multiblock copolymers with ≈100 blocks in only 2 to 4 steps. [ABSTRACT FROM AUTHOR]

Multiblock copolymers are envisioned as promising materials with enhanced properties and functionality compared with their diblock/triblock counterparts. However, the current approaches can construct multiblock copolymers with a limited number of blocks but tedious procedures. Here, we report a thioester‐relayed in‐chain cascade copolymerization strategy for the easy preparation of multiblock copolymers with on‐demand blocks, in which thioester groups with on‐demand numbers are built in the polymer backbone by controlled/living polymerizations. These thioester groups further serve as the in‐chain initiating centers to trigger the acyl group transfer ring‐opening polymerization of episulfides independently and concurrently to extend the polymer backbone into multiblock structures. The compositions, number of blocks, and block degree of polymerization can be easily regulated. This strategy can offer easy access to a library of multiblock copolymers with ≈100 blocks in only 2 to 4 steps. [ABSTRACT FROM AUTHOR]

Poly(amidoamine)s (PAMAMs) of high-generations (G ＞ 5) exhibit high efficacy in gene transfection, but their high cost and severe cytotoxicity limit their use in biomedicine. In contrast, PAMAMs of low-generations (G ＜ 3) are less toxic and easy to synthesize, but exhibit low transfection efficacy. In this report, we design a novel amphiphilic dendrimer by conjugating reactive oxygen species (ROS)-responsive poly(propylenesulfide) (PPS) to a low generation PAMAM dendrimer (G = 2, Mw = 3500 Da) via disulfide bonds. This amphiphilic conjugate can self-assemble into stable nanomicelles. The results show that the obtained nanomicelles have a high zeta potential, which can condense DNA tightly. Moreover, the DNA/nanomicelle polyplexes can be fully dissociated by intracellular ROS and easily release the entrapped DNA. As gene vectors, the nanomicelles exhibited high transfection efficacy and fairly low cytotoxicity in vitro. [ABSTRACT FROM AUTHOR]

Marangoni‐effect‐driven actuators (MDAs) have the advantages of direct light‐to‐work conversion and convenient operation, which makes it widely researched in the cutting‐edge fields including robots, micromachines, and intelligent systems. However, the MDA relies on the surface tension difference and it only works on the 2D liquid–air interface. Besides, the MDAs are normally pure black due to the light‐absorption material limitation. Herein, a transparent light‐driven 3D movable actuator (LTMA) and a 3D manipulation strategy are proposed. The LTMA is composed of photothermal nanoparticles‐doped temperature‐responsive hydrogel, whose surface energy changes as the nanoparticles absorb light energy. The 3D manipulation strategy combines Marangoni effect with photothermal buoyancy flow for realizing complex self‐propellant and floating/sinking motions. The LTMA can perform more advanced tasks such as 3D obstacle avoidance and 3D sampling. Benefiting from the porous structure of hydrogel, LTMA can naturally absorb the chemical molecules for remote sampling and automated drug delivery. The light‐driven, transparent, three‐dimensionally movable, and programmable actuator has promising prospects in the field of micromachines and intelligent systems. [ABSTRACT FROM AUTHOR]

Impinging jet fire of high exit momentum is frequently reported to induce the domino effect in industry fires. Less literature is available for the flame extension area and temperature distribution over a vertical plate impinged by the horizontal jet flame. Thus, this paper conducts a systematic experiment to reveal the effect of nozzle exit velocity, exit diameter and exit-plate spacing on the horizontally impinging jet fire. Experimental observation shows the evolution of flame pattern and color with an increase of exit velocity and a decrease of exit-plate spacing. The flame extension area induced by the horizontal jet flame impingement was measured by a novel method that combines the picture processing technique and the thermal imaging technique. By physical analysis, a new correlation coupling the turbulent Karlovitz stretch factor and the ratio of nozzle exit diameter to exit-plate spacing, was developed for the flame extension area of both horizontally and vertically impinging jet fire. The variation of maximum temperature in the impinging zone with the exit-plate spacing still fits the classic correlation of centerline temperature in the continuous and intermittent flames. However, the horizontally impinging jet fire plume holds a shorter intermittent flame region due to the flame upward bending. It is found that the temperature profile holds a big difference in the upward and downward directions along the vertical plate. A new uniform correlation, with the plume radius as the characteristic length scale, is proposed to well collapse all the temperature data in the impinging zone. [ABSTRACT FROM AUTHOR]

Visible light‐driving syntheses have emerged as a powerful tool for organic synthesis and for the preparation of macromolecules under mild and environmentally benign conditions. However, precious but nonreusable photosensitizers or photocatalysts are often required to activate the reaction, limiting its practicality. Here, it is reported that poly(1,4‐diphenylbutadiyne) (PDPB) nanofibers exhibit remarkable activity in driving the living free radical polymerization under visible light. Moreover, PDPB nanofibers are very stable under irradiation of visible light and can be reused without appreciable loss of activity even after repeated cycling. The nanofiber will be a promising photocatalyst with excellent reusability and stability for the reactions driven by visible light. [ABSTRACT FROM AUTHOR]

• A copolymer that could target and create fast closable holes in the cell membrane. • Direct delivery of exogenous genes into cell cytosol, avoiding endosome trapping. • Achieving high gene transfection and deep penetration into tumor tissue. Delivering exogenous compounds into cells in vitro or in vivo is a critical yet very challenging step in gene- and cell-based therapies, biomanufacturing, and basic research. Although several nanotechnologies could highly facilitate exogenous compounds into the target cell, they are typically internalized by cells into membrane-bounded endosomes, and most of them are trapped in these endosomes and degraded by endosomes, failing to access the cytosolic cell machinery. Here, we have prepared a copolymer that could target and create fast closable holes in the cell membrane, via which the exogenous genes in nanoparticles can be directly delivered into the cell cytosol, highly bypassing the severe endosome trapping of normal delivery approaches and achieving high gene transfection. Moreover, in cells, the copolymer undergoes fast deboronation to release the absorbed lipid for fast repair of the holes. This cell membrane hole-creating copolymer would provide a very promising means for delivering functional nanoparticles, DNA, RNA, and proteins directly into the cell cytosol, avoiding cargo entrapment in endosomes and maintaining cargo functionality after delivery. [ABSTRACT FROM AUTHOR]

It is difficult to detect ports in polarimetric SAR images due to the complicated components, morphology, and coastal environment. This paper proposes an unsupervised port detection method by extracting the water of the port based on three-component decomposition and multi-scale thresholding segmentation. Firstly, the polarimetric characteristics of the port water are analyzed using modified three-component decomposition. Secondly, the volume scattering power and the power ratio of the double-bounce scattering power to the volume scattering power (PRDV) are used to extract the port water. Water and land are first separated by a global thresholding segmentation of the volume scattering power, in which the sampling region used for the threshold calculation is automatically selected by a proposed homogeneity measure. The interference water regions in the ports are then separated from the water by segmenting the PRDV using the multi-scale thresholding segmentation method. The regions of interest (ROIs) of the ports are then extracted by determining the connected interference water regions with a large area. Finally, ports are recognized by examining the area ratio of strong scattering pixels to the land in the extracted ROIs. Seven single quad-polarization SAR images acquired by RADARSAT-2 covering the coasts of Dalian, Zhanjiang, Fujian, Tianjin, Lingshui, and Boao in China and Berkeley in America are used to test the proposed method. The experimental results show that all ports are correctly and quickly detected. The false alarm rates are zero, the intersection of union section (IoU) indexes between the detected port and the ground truth can reach 75%, and the average processing time can be less than 100 s. [ABSTRACT FROM AUTHOR]

• New correlation is built for the flame geometry of horizontal jet fire of shape-different exits. • The exit shape coefficient dominates the phenomenological constant of flame length correlation. • Richardson number dominates the upward tilt of horizontal jet flame. • A revised dimensionless flow number is proposed to fit the lift-off distance. The accidental releases of high pressure gas fuel could lead to the jet fires, resulting in a serious of disastrous events. This paper presents a systematical investigation upon the effect of nozzle exit shape on the horizontal jet flame geometry by experiments. The nozzles of circular, rectangular, equilateral triangle and elliptic exits were used for experimental tests. New correlations for the horizontally projected flame length, vertically projected flame height and lift-off distance are established for horizontal jet fires ejected from the exits of different shapes. The exit shape coefficient (the ratio of hydraulic to equivalent diameters) is found to dominate the phenomenological constant in the classic correlation of flame length, and the dependency of phenomenological constant on exit shape coefficient is quantified. It is also clarified that Richardson number (the ratio of flame buoyancy to exit momentum) dominates the ratio of vertically projected flame height to horizontally projected flame length. The hydraulic diameter is proposed to revise the dimensionless flow number, for physically addressing the effect of exit shape on the lift-off distance of horizontal jet flame. [ABSTRACT FROM AUTHOR]

Photocatalyzed polymerization using organic molecules as catalysts has attracted broad interest because of its easy operation in ambient environments and low toxicity compared with metallic catalysts. In this work, we reported that 4,7-di(thiophen-2-yl)benzo[c][1,2,5]thiadiazole (DTBT) can act as an efficient photoredox catalyst for photoinduced electron transfer-reversible addition-fragmentation chain transfer (PET-RAFT) polymerization under green light irradiation. Well-defined (co)polymers can be obtained using this technique without any additional additives like noble metals and electron donors or acceptors. The living characteristics of polymerization were verified by kinetic study and the narrow dispersity (Đ) of the produced polymer. Excellent chain-end fidelity was demonstrated through chain extension as well. In addition, this technique showed great potential for various RAFT agents and monomers including acrylates and acrylamides. [ABSTRACT FROM AUTHOR]