Search

Real-world data generation often involves complex inter-dependencies among instances, violating the IID-data hypothesis of standard learning paradigms and posing a challenge for uncovering the geometric structures for learning desired instance representations. To this end, we introduce an energy constrained diffusion model which encodes a batch of instances from a dataset into evolutionary states that progressively incorporate other instances' information by their interactions. The diffusion process is constrained by descent criteria w.r.t.~a principled energy function that characterizes the global consistency of instance representations over latent structures. We provide rigorous theory that implies closed-form optimal estimates for the pairwise diffusion strength among arbitrary instance pairs, which gives rise to a new class of neural encoders, dubbed as DIFFormer (diffusion-based Transformers), with two instantiations: a simple version with linear complexity for prohibitive instance numbers, and an advanced version for learning complex structures. Experiments highlight the wide applicability of our model as a general-purpose encoder backbone with superior performance in various tasks, such as node classification on large graphs, semi-supervised image/text classification, and spatial-temporal dynamics prediction., Published at ICLR 2023 as a spotlight presentation, the implementation code is available at https://github.com/qitianwu/DIFFormer

As simulation technology plays an increasingly important role in the development of precision-guided weapons, it is urgent to study theories and methods in the intelligent, standardized and industrialized simulation technology. This paper mainly introduces the development status of guided weapon system simulation technologies in and outside of China in recent years. The domestic and foreign development of simulation technologies, methods and equipment of different guided weapon systems, including the system of image, laser, millimeter wave and integrated navigation, is compared and analyzed in detail. Finally, the insufficiency, development trend, and coping strategies of China’s guided weapon simulation technologies are proposed.

Networks are ubiquitous in many real-world applications (e.g., social networks encoding trust/distrust relationships, correlation networks arising from time series data). While many networks are signed or directed, or both, there is a lack of unified software packages on graph neural networks (GNNs) specially designed for signed and directed networks. In this paper, we present PyTorch Geometric Signed Directed (PyGSD), a software package which fills this gap. Along the way, we also provide a brief review surveying typical tasks, loss functions and evaluation metrics in the analysis of signed and directed networks, discuss data used in related experiments, provide an overview of methods proposed, and evaluate the implemented methods with experiments. The deep learning framework consists of easy-to-use GNN models, synthetic and real-world data, as well as task-specific evaluation metrics and loss functions for signed and directed networks. As an extension library for PyG, our proposed software is maintained with open-source releases, detailed documentation, continuous integration, unit tests and code coverage checks. Our code is publicly available at \url{https://github.com/SherylHYX/pytorch_geometric_signed_directed}.

Many real world applications can be formulated as event forecasting on Continuous Time Dynamic Graphs (CTDGs) where the occurrence of a timed event between two entities is represented as an edge along with its occurrence timestamp in the graphs.However, most previous works approach the problem in compromised settings, either formulating it as a link prediction task on the graph given the event time or a time prediction problem given which event will happen next. In this paper, we propose a novel model combining Graph Neural Networks and Marked Temporal Point Process (MTPP) that jointly forecasts multiple link events and their timestamps on communities over a CTDG. Moreover, to scale our model to large graphs, we factorize the jointly event prediction problem into three easier conditional probability modeling problems.To evaluate the effectiveness of our model and the rationale behind such a decomposition, we establish a set of benchmarks and evaluation metrics for this event forecasting task. Our experiments demonstrate the superior performance of our model in terms of both model accuracy and training efficiency.

Node clustering is a powerful tool in the analysis of networks. We introduce a graph neural network framework, named DIGRAC, to obtain node embeddings for directed networks in a self-supervised manner, including a novel probabilistic imbalance loss, which can be used for network clustering. Here, we propose \textit{directed flow imbalance} measures, which are tightly related to directionality, to reveal clusters in the network even when there is no density difference between clusters. In contrast to standard approaches in the literature, in this paper, directionality is not treated as a nuisance, but rather contains the main signal. DIGRAC optimizes directed flow imbalance for clustering without requiring label supervision, unlike existing graph neural network methods, and can naturally incorporate node features, unlike existing spectral methods. Extensive experimental results on synthetic data, in the form of directed stochastic block models, and real-world data at different scales, demonstrate that our method, based on flow imbalance, attains state-of-the-art results on directed graph clustering when compared against 10 state-of-the-art methods from the literature, for a wide range of noise and sparsity levels, graph structures, and topologies, and even outperforms supervised methods., 43 pages, 10 pages for the main text, accepted by the LoG2022 conference

The prevalence of graph-based data has spurred the rapid development of graph neural networks (GNNs) and related machine learning algorithms. Yet, despite the many datasets naturally modeled as directed graphs, including citation, website, and traffic networks, the vast majority of this research focuses on undirected graphs. In this paper, we propose MagNet, a spectral GNN for directed graphs based on a complex Hermitian matrix known as the magnetic Laplacian. This matrix encodes undirected geometric structure in the magnitude of its entries and directional information in their phase. A "charge" parameter attunes spectral information to variation among directed cycles. We apply our network to a variety of directed graph node classification and link prediction tasks showing that MagNet performs well on all tasks and that its performance exceeds all other methods on a majority of such tasks. The underlying principles of MagNet are such that it can be adapted to other spectral GNN architectures., Comment: 22 pages, 4 figures, 15 tables. v2: Numerous revisions to the paper's content, including: a more general and informative presentation; many new numerical experiments; revised figures

Distance-dependent magnetic resonance tuning (MRET) technology enables the sensing and quantitative imaging of biological targets in vivo, with the advantage of deep tissue penetration and fewer interactions with the surroundings as compared with those of fluorescence-based Förster resonance energy transfer. However, applications of MRET technology in vivo are currently limited by the moderate contrast enhancement and stability of T1-based MRET probes. Here we report a new two-way magnetic resonance tuning (TMRET) nanoprobe with dually activatable T1 and T2 magnetic resonance signals that is coupled with dual-contrast enhanced subtraction imaging. This integrated platform achieves a substantially improved contrast enhancement with minimal background signal and can be used to quantitatively image molecular targets in tumours and to sensitively detect very small intracranial brain tumours in patient-derived xenograft models. The high tumour-to-normal tissue ratio offered by TMRET in combination with dual-contrast enhanced subtraction imaging provides new opportunities for molecular diagnostics and image-guided biomedical applications.

Distance-dependent magnetic resonance tuning (MRET) technology enables the sensing and quantitative imaging of biological targets in vivo, with the advantage of deep tissue penetration and fewer interactions with the surroundings as compared with those of fluorescence-based Förster resonance energy transfer. However, applications of MRET technology in vivo are currently limited by the moderate contrast enhancement and stability of T1-based MRET probes. Here we report a new two-way magnetic resonance tuning (TMRET) nanoprobe with dually activatable T1 and T2 magnetic resonance signals that is coupled with dual-contrast enhanced subtraction imaging. This integrated platform achieves a substantially improved contrast enhancement with minimal background signal and can be used to quantitatively image molecular targets in tumours and to sensitively detect very small intracranial brain tumours in patient-derived xenograft models. The high tumour-to-normal tissue ratio offered by TMRET in combination with dual-contrast enhanced subtraction imaging provides new opportunities for molecular diagnostics and image-guided biomedical applications.

In the present work, a thorough investigation has been conducted on the Co-B alloys in terms of the microstructure evolution during non-equilibrium solidification with/without magnetic field and the temperature induced liquid-liquid structure transition.In this work, a Co-20at.%B hypereutectic alloys was undercooled by the melt fluxing technique and the microstructure was characterized by the back-scattering diffraction technique. A transition from hypereutectic to hypoeutectic was found at a critical undercooling of ∆T=119 K. When ∆T119 K, the above hypereutectic microstructure changes into hypoeutectic structure with the α-Co phase as the primary phase. According to dendrite growth model, the transition from hypereutectic to hypoeutectic can be ascribed to the higher growth velocity of the α-Co phase than the β-Co3B phase, i.e., the growth-controlled mechanism. The current work shows also that there is a coupled zone skewed to the β-Co3B phase in the Co-B alloys system.Cyclic superheating and cooling were carried out for the undercooled hypereutectic Co-20at.%B, eutectic Co-18.5at.%B and hypoeutectic Co-17at.%B alloys. For each alloy, there is a critical overheating temperature Tc0 at which there is a sharp increase of the mean undercooling, i.e., the mean undercooling is about 80 °C when the overheating temperature is below Tc0, whereas the mean undercooling is about 200 °C when the overheating temperature is above Tc0. DSC measurements show that there is a thermal absorption peak in the heating process, the peak temperature of which is nearly equal to the critical overheating temperature, indicating that the temperature induced liquid-liquid structure transition does occur and should relate highly to nucleation in the undercooled Co-B eutectic melts. The effect of the liquid-liquid structure transition on nucleation was interpreted by the recent nucleation theory that considers the structures of overheated melts, and the composition-dependent overheating temperature was ascribed to the change of local favored structures. The present work provides further evidences for the liquid-liquid structure transition and is helpful for understanding solidification in undercooled melts.By in situ measuring the magnetization, the temperature induced liquid-liquid structure transition was further investigated. A magnetization anomaly in term of the non-Curie-Weiss temperature dependence of magnetization was observed in the overheated state, demonstrating a temperature induced liquid-liquid structure transition. This anomalous behavior was found to be a universal formula for the Co-B binary alloy system. A transition point (T0), two different Curie constants and two paramagnetic Curie temperatures (θ(LI), θ(LII)) corresponding to two distinct kinds of liquids (i.e., high-magnetization liquid I and low-magnetization liquid II) are determined. The Curie constant of liquid II was found much higher, which is attributed to the survived covalent bond below T0. The effects of magnetic field intensity on the liquid-liquid structure transition and paramagnetic Curie temperatures are studied. T0 and θ(LII) are found not sensitive to the field intensity, whereas, θ(LI) shifts to lower temperatures with the increasing magnetic field intensity. With the increased concentration of Co, T0, θ(LI) and θ(LII) shift to higher temperatures and the Curie constants for the liquid I and liquid II decrease. Based on the location of T0, a guideline was drawn above the liquidus in the Co-B phase diagram, which could provide a significant guidance to the practical melt treatment.Under an imposed magnetic field, a morphological alignment was found for the primary α-Co phase with its primary dendrite trunk or long axis paralleling to the direction of magnetic field. The primary α-Co phases are rod-like or spherical at relatively high undercooling, and the application of magnetic field is more conducive to obtain such kind of α-Co phases. The magnetic energy, magnetic torque and time required for rotation were analyzed theoretically to evaluate the magnetic alignment and alignment mechanisms. The dipolar forces between particles were calculated, based on which the phenomenon that the primary α-Co particles self-organize as chain-like stacking was described.; Dans le cadre du présent travail, une étude approfondie a été menée sur les alliages Co-B en termes d'évolution de la microstructure lors d'une solidification hors équilibre avec ou sans champ magnétique ainsi que sur une transition liquide-liquide induite par la température.Dans ce travail, un alliage hypereutectique Co-20at.%B a été sous-refroidi par la technique de l'encapsulation vitreuse et la microstructure a été caractérisée par la technique de microscopie électronique par électrons rétrodiffusés. Une transition de l'hypereutectique à l'hypoeutectique a été trouvée à un sous-refroidissement critique de ∆T=119 K. Quand ∆T119 K, la microstructure hypereutectique ci-dessus se transforme en structure hypoeutectique avec la phase α-Co comme phase primaire. Selon le modèle de croissance de la dendrite, le passage de l'hypereutectique à l'hypoeutectique peut être attribué à la vitesse de croissance plus élevée de la phase α-Co que de la phase β-Co3B, c'est-à-dire un mécanisme contrôlé par la croissance. Les travaux actuels montrent également qu'il existe une zone de couplage dévié avec la phase β-Co3B dans le système des alliages Co-B.La surchauffe et le refroidissement cycliques ont été effectués pour les alliages hypereutectiques sous-refroidis Co-20at.%B, eutectiques Co-18.5at.%B et hypoeutectiques Co-17at.%B. Pour chaque alliage, il y a une température critique de surchauffe Tc0 à laquelle il y a une brutale augmentation du sous-refroidissement moyen, c'est-à-dire passant de 80°C pour une surchauffe inférieure Tc0, à 200 °C pour une surchauffe supérieure à Tc0. Les mesures DSC montrent qu'il y a un pic d'absorption thermique dans le processus de chauffage, dont le pic de température est presque égal à la température critique de surchauffe, ce qui indique qu'une transition structurale liquide-liquide induite par la température se produit et doit être étroitement liée à la nucléation dans le liquide eutectique Co-B sous refroidi. L'effet de la transition structurale liquide-liquide sur la nucléation a été interprété par la récente théorie de la nucléation qui considère les structures des liquides en fusion surchauffées, et la température de surchauffe critique TcO, dépendante de la composition, a été attribuée au changement de structures préférentielles locales. Le présent travail fournit d'autres preuves de la transition structurale liquide-liquide et est utile pour comprendre la solidification dans les métaux liquides sous-refroidis.Grace à une mesure in situ de l'aimantation, la transition structurale liquide-liquide induite par la température a été étudiée plus en profondeur. Une anomalie d'aimantation en terme de non dépendance de l'aimantation selon une loi de Curie-Weiss a été observée à l'état surchauffé, ce qui démontre une transition structurale liquide-liquide induite par la température. Ce comportement anormal s'est avéré être une règle universelle pour le système d'alliage binaire Co-B. Une température de transition (T0) et deux températures de Curie paramagnétiques (θ(LI), θ(LII)) correspondant à deux structures différentes des liquides sont déterminées. Les effets de l'intensité du champ magnétique sur la transition liquide-liquide et les températures de Curie paramagnétiques sont étudiés. T0 et θ(LII) ne sont pas sensibles à l'intensité du champ, tandis que θ(LI) passe à des températures plus basses avec une intensité croissante du champ magnétique. Avec une concentration croissante de Cobalt, T0, θ(LI) et θ(LII) passent à des températures plus élevées et les constantes de Curie pour le liquide I et le liquide II diminuent. En se basant sur la mesure de T0, une ligne directrice a été tracée au-dessus du liquidus dans le diagramme de phase Co-B, ce qui pourrait fournir une aide significative pour le traitement pratique de fusion de l'alliage.Sous l'effet d'un champ magnétique imposé, un alignement morphologique a été trouvé pour la phase primaire α-Co avec son tronc primaire de dendrite ou son grand axe parallèle à la direction du champ magnétique. Les phases primaires de α-Co sont de formes cylindriques ou sphériques avec un sous-refroidissement relativement élevé, et l'application d'un champ magnétique est plus propice à l'obtention de ce type de phases α-Co. L'énergie magnétique, le couple magnétique et le temps requis pour la rotation ont été analysés théoriquement pour évaluer l'alignement magnétique et les mécanismes d'alignement. Les forces dipolaires entre les particules ont été calculées sur la base desquelles le phénomène d'auto-organisation des particules primaires de α-Co sous forme d'empilement en chaîne a été décrit.

In the present work, a thorough investigation has been conducted on the Co-B alloys in terms of the microstructure evolution during non-equilibrium solidification with/without magnetic field and the temperature induced liquid-liquid structure transition.In this work, a Co-20at.%B hypereutectic alloys was undercooled by the melt fluxing technique and the microstructure was characterized by the back-scattering diffraction technique. A transition from hypereutectic to hypoeutectic was found at a critical undercooling of ∆T=119 K. When ∆T119 K, the above hypereutectic microstructure changes into hypoeutectic structure with the α-Co phase as the primary phase. According to dendrite growth model, the transition from hypereutectic to hypoeutectic can be ascribed to the higher growth velocity of the α-Co phase than the β-Co3B phase, i.e., the growth-controlled mechanism. The current work shows also that there is a coupled zone skewed to the β-Co3B phase in the Co-B alloys system.Cyclic superheating and cooling were carried out for the undercooled hypereutectic Co-20at.%B, eutectic Co-18.5at.%B and hypoeutectic Co-17at.%B alloys. For each alloy, there is a critical overheating temperature Tc0 at which there is a sharp increase of the mean undercooling, i.e., the mean undercooling is about 80 °C when the overheating temperature is below Tc0, whereas the mean undercooling is about 200 °C when the overheating temperature is above Tc0. DSC measurements show that there is a thermal absorption peak in the heating process, the peak temperature of which is nearly equal to the critical overheating temperature, indicating that the temperature induced liquid-liquid structure transition does occur and should relate highly to nucleation in the undercooled Co-B eutectic melts. The effect of the liquid-liquid structure transition on nucleation was interpreted by the recent nucleation theory that considers the structures of overheated melts, and the composition-dependent overheating temperature was ascribed to the change of local favored structures. The present work provides further evidences for the liquid-liquid structure transition and is helpful for understanding solidification in undercooled melts.By in situ measuring the magnetization, the temperature induced liquid-liquid structure transition was further investigated. A magnetization anomaly in term of the non-Curie-Weiss temperature dependence of magnetization was observed in the overheated state, demonstrating a temperature induced liquid-liquid structure transition. This anomalous behavior was found to be a universal formula for the Co-B binary alloy system. A transition point (T0), two different Curie constants and two paramagnetic Curie temperatures (θ(LI), θ(LII)) corresponding to two distinct kinds of liquids (i.e., high-magnetization liquid I and low-magnetization liquid II) are determined. The Curie constant of liquid II was found much higher, which is attributed to the survived covalent bond below T0. The effects of magnetic field intensity on the liquid-liquid structure transition and paramagnetic Curie temperatures are studied. T0 and θ(LII) are found not sensitive to the field intensity, whereas, θ(LI) shifts to lower temperatures with the increasing magnetic field intensity. With the increased concentration of Co, T0, θ(LI) and θ(LII) shift to higher temperatures and the Curie constants for the liquid I and liquid II decrease. Based on the location of T0, a guideline was drawn above the liquidus in the Co-B phase diagram, which could provide a significant guidance to the practical melt treatment.Under an imposed magnetic field, a morphological alignment was found for the primary α-Co phase with its primary dendrite trunk or long axis paralleling to the direction of magnetic field. The primary α-Co phases are rod-like or spherical at relatively high undercooling, and the application of magnetic field is more conducive to obtain such kind of α-Co phases. The magnetic energy, magnetic torque and time required for rotation were analyzed theoretically to evaluate the magnetic alignment and alignment mechanisms. The dipolar forces between particles were calculated, based on which the phenomenon that the primary α-Co particles self-organize as chain-like stacking was described.; Dans le cadre du présent travail, une étude approfondie a été menée sur les alliages Co-B en termes d'évolution de la microstructure lors d'une solidification hors équilibre avec ou sans champ magnétique ainsi que sur une transition liquide-liquide induite par la température.Dans ce travail, un alliage hypereutectique Co-20at.%B a été sous-refroidi par la technique de l'encapsulation vitreuse et la microstructure a été caractérisée par la technique de microscopie électronique par électrons rétrodiffusés. Une transition de l'hypereutectique à l'hypoeutectique a été trouvée à un sous-refroidissement critique de ∆T=119 K. Quand ∆T119 K, la microstructure hypereutectique ci-dessus se transforme en structure hypoeutectique avec la phase α-Co comme phase primaire. Selon le modèle de croissance de la dendrite, le passage de l'hypereutectique à l'hypoeutectique peut être attribué à la vitesse de croissance plus élevée de la phase α-Co que de la phase β-Co3B, c'est-à-dire un mécanisme contrôlé par la croissance. Les travaux actuels montrent également qu'il existe une zone de couplage dévié avec la phase β-Co3B dans le système des alliages Co-B.La surchauffe et le refroidissement cycliques ont été effectués pour les alliages hypereutectiques sous-refroidis Co-20at.%B, eutectiques Co-18.5at.%B et hypoeutectiques Co-17at.%B. Pour chaque alliage, il y a une température critique de surchauffe Tc0 à laquelle il y a une brutale augmentation du sous-refroidissement moyen, c'est-à-dire passant de 80°C pour une surchauffe inférieure Tc0, à 200 °C pour une surchauffe supérieure à Tc0. Les mesures DSC montrent qu'il y a un pic d'absorption thermique dans le processus de chauffage, dont le pic de température est presque égal à la température critique de surchauffe, ce qui indique qu'une transition structurale liquide-liquide induite par la température se produit et doit être étroitement liée à la nucléation dans le liquide eutectique Co-B sous refroidi. L'effet de la transition structurale liquide-liquide sur la nucléation a été interprété par la récente théorie de la nucléation qui considère les structures des liquides en fusion surchauffées, et la température de surchauffe critique TcO, dépendante de la composition, a été attribuée au changement de structures préférentielles locales. Le présent travail fournit d'autres preuves de la transition structurale liquide-liquide et est utile pour comprendre la solidification dans les métaux liquides sous-refroidis.Grace à une mesure in situ de l'aimantation, la transition structurale liquide-liquide induite par la température a été étudiée plus en profondeur. Une anomalie d'aimantation en terme de non dépendance de l'aimantation selon une loi de Curie-Weiss a été observée à l'état surchauffé, ce qui démontre une transition structurale liquide-liquide induite par la température. Ce comportement anormal s'est avéré être une règle universelle pour le système d'alliage binaire Co-B. Une température de transition (T0) et deux températures de Curie paramagnétiques (θ(LI), θ(LII)) correspondant à deux structures différentes des liquides sont déterminées. Les effets de l'intensité du champ magnétique sur la transition liquide-liquide et les températures de Curie paramagnétiques sont étudiés. T0 et θ(LII) ne sont pas sensibles à l'intensité du champ, tandis que θ(LI) passe à des températures plus basses avec une intensité croissante du champ magnétique. Avec une concentration croissante de Cobalt, T0, θ(LI) et θ(LII) passent à des températures plus élevées et les constantes de Curie pour le liquide I et le liquide II diminuent. En se basant sur la mesure de T0, une ligne directrice a été tracée au-dessus du liquidus dans le diagramme de phase Co-B, ce qui pourrait fournir une aide significative pour le traitement pratique de fusion de l'alliage.Sous l'effet d'un champ magnétique imposé, un alignement morphologique a été trouvé pour la phase primaire α-Co avec son tronc primaire de dendrite ou son grand axe parallèle à la direction du champ magnétique. Les phases primaires de α-Co sont de formes cylindriques ou sphériques avec un sous-refroidissement relativement élevé, et l'application d'un champ magnétique est plus propice à l'obtention de ce type de phases α-Co. L'énergie magnétique, le couple magnétique et le temps requis pour la rotation ont été analysés théoriquement pour évaluer l'alignement magnétique et les mécanismes d'alignement. Les forces dipolaires entre les particules ont été calculées sur la base desquelles le phénomène d'auto-organisation des particules primaires de α-Co sous forme d'empilement en chaîne a été décrit.

International audience

The relationship between microbial diversity and sludge toxicity in the biotreatment of refractory wastewater was investigated. Synthetic wastewater containing 4-chlorophenol (4-CP) was treated by an activated sludge using a sequencing batch bioreactor (SBR). At the end of a single SBR cycle, a stable operation stage was reached when the 4-CP was not detected both in aqueous and sludge phases and the effluent COD was maintained at approximately 70 mg L(-1) for the blank and control sludge groups. Then, the diversity of the microorganisms and the sludge toxicity were measured. The results showed that the Microtox acute toxicity of the control sludge was higher than those of the blank sludge. The difference analysis of the microbial diversity between the blank and control sludge indicated that the sludge toxicity was closely related to microbial diversity.

International audience

AimThis study aims to develop new nanoformulations of EGFR T790M targeted inhibitor AZD9291 and paclitaxel (PTX) for combination therapy of lung cancer.Materials & methodsWe prepared and characterized PTX- and AZD9291-loaded disulfide cross-linking micelles (DCMs), and evaluate their combination effect and toxicity in vitro and in lung cancer-bearing mice.ResultsDrug-loaded DCMs were relatively small in size, and possessed glutathione-responsive drug release. The combination of PTX-DCMs and AZD92921-DCMs exhibited strong synergistic effects in both cell line and in vivo without additional toxicity. Molecular studies demonstrated the synergistic modification in both IKB-α/NF-κB/Bcl-2 and EGFR/Akt pathways.ConclusionThe combination of DCM-loaded AZD9291 and PTX could potentially offer more effective and less toxicity treatment options for lung cancer patients.

Although deep CNNs have brought significant improvement to image saliency detection, most CNN based models are sensitive to distortion such as compression and noise. In this paper, we propose an end-to-end generic salient object segmentation model called Metric Expression Network (MEnet) to deal with saliency detection with the tolerance of distortion. Within MEnet, a new topological metric space is constructed, whose implicit metric is determined by the deep network. As a result, we manage to group all the pixels in the observed image semantically within this latent space into two regions: a salient region and a non-salient region. With this architecture, all feature extractions are carried out at the pixel level, enabling fine granularity of output boundaries of the salient objects. What's more, we try to give a general analysis for the noise robustness of the network in the sense of Lipschitz and Jacobian literature. Experiments demonstrate that robust salient maps facilitating object segmentation can be generated by the proposed metric. Tests on several public benchmarks show that MEnet has achieved desirable performance. Furthermore, by direct computation and measuring the robustness, the proposed method outperforms previous CNN-based methods on distorted inputs., Comment: This version: 11 pages (12 with reference), 12 figures, 5 table; Version 1: 7 pages,7 figures, 4 tables; The paper for version 1 has been accepted by International Joint Conference on Artificial Intelligence (IJCAI),2018

Sludge toxicity, as determined by the inhibition of luminescence in the bacterium Photobacterium phosphoreum ( P. phosphoreum ), was formed during either acclimating or shocking starting processes with high concentrations of N, N-dimethylformamide (DMF). In the acclimating starting process, the sludge was first acclimated with 120 mg L −1 DMF before 200 mg L −1 DMF was added, whereas in the shock starting process, the sludge was fed with 200 mg L −1 DMF directly. The results showed that the toxicity of the sludge shocked with 200 mg L −1 DMF was significantly higher than that of the acclimated sludge throughout the entire process. The maximum toxicity gap between the shocked and acclimated sludge appeared at the initial stage, and the gap decreased with operation time. In addition, the maximum toxicity existed for 6–8 h in a single SBR cycle, regardless of the starting process. Proteomics analysis indicated that the responses of the shocked and acclimated sludge to DMF stimulation were different. As a result, toxic substances accumulated in the sludge through various factors, including secretions from two types of sludge under DMF stress conditions.

This study investigated sludge toxicity in removal of 4-chlorophenol (4-CP) in reactor system with addition of methanol. The toxicity was evaluated in two sequential batch reactors (SBRs), namely acclimated sludge reactor with addition of 10 mg l−1 4-CP and control sludge reactor without 4-CP addition. Results showed that even though 4-CP both in aqueous and sludge phases was undetectable, the toxicity of the acclimated sludge was still higher than the control sludge, which was assessed with Photobacterium phosphoreum (P. phosphoreum). Adsorption and biodegradation assays indicated that secondary metabolites from microorganism also contributed to sludge toxicity in addition to 4-CP itself. The different molecular-weight (MW) distribution of organic substances in sludge analysis validated that the mass fractions of TOC at >10 K and 10 K-500 were significantly related to the sludge toxicity.