Untargeted Black-box Attacks for Social Recommendations

The rise of online social networks has facilitated the evolution of social recommender systems, which incorporate social relations to enhance users' decision-making process. With the great success of Graph Neural Networks in learning node representations, GNN-based social recommendations have been widely studied to model user-item interactions and user-user social relations simultaneously. Despite their great successes, recent studies have shown that these advanced recommender systems are highly vulnerable to adversarial attacks, in which attackers can inject well-designed fake user profiles to disrupt recommendation performances. While most existing studies mainly focus on targeted attacks to promote target items on vanilla recommender systems, untargeted attacks to degrade the overall prediction performance are less explored on social recommendations under a black-box scenario. To perform untargeted attacks on social recommender systems, attackers can construct malicious social relationships for fake users to enhance the attack performance. However, the coordination of social relations and item profiles is challenging for attacking black-box social recommendations. To address this limitation, we first conduct several preliminary studies to demonstrate the effectiveness of cross-community connections and cold-start items in degrading recommendations performance. Specifically, we propose a novel framework Multiattack based on multi-agent reinforcement learning to coordinate the generation of cold-start item profiles and cross-community social relations for conducting untargeted attacks on black-box social recommendations. Comprehensive experiments on various real-world datasets demonstrate the effectiveness of our proposed attacking framework under the black-box setting.Comment: Preprint. Under revie

Nonlinear Inertia Classification Model and Application

Classification model of support vector machine (SVM) overcomes the problem of a big number of samples. But the kernel parameter and the punishment factor have great influence on the quality of SVM model. Particle swarm optimization (PSO) is an evolutionary search algorithm based on the swarm intelligence, which is suitable for parameter optimization. Accordingly, a nonlinear inertia convergence classification model (NICCM) is proposed after the nonlinear inertia convergence (NICPSO) is developed in this paper. The velocity of NICPSO is firstly defined as the weighted velocity of the inertia PSO, and the inertia factor is selected to be a nonlinear function. NICPSO is used to optimize the kernel parameter and a punishment factor of SVM. Then, NICCM classifier is trained by using the optical punishment factor and the optical kernel parameter that comes from the optimal particle. Finally, NICCM is applied to the classification of the normal state and fault states of online power cable. It is experimentally proved that the iteration number for the proposed NICPSO to reach the optimal position decreases from 15 to 5 compared with PSO; the training duration is decreased by 0.0052 s and the recognition precision is increased by 4.12% compared with SVM

Pharmacological Effects of Two Novel Bombesin-Like Peptides from the Skin Secretions of Chinese Piebald Odorous Frog (Odorrana schmackeri) and European Edible Frog (Pelophylax kl. esculentus) on Smooth Muscle

Bombesin-like peptides, which were identified from a diversity of amphibian skin secretions, have been demonstrated to possess several biological functions such as stimulation of smooth muscle contraction and regulation of food intake. Here, we report two novel bombesin-like peptides, bombesin-OS and bombesin-PE, which were isolated from Odorrana schmackeri and Pelophylax kl. esculentus, respectively. The mature peptides were identified and structurally confirmed by high performance Scliquid chromatography (HPLC) and tandem mass spectrometry (MS/MS). Subsequently, the effects of these purified chemically-synthetic peptides on smooth muscle were determined in bladder, uterus, and ileum. The synthetic replications were revealed to have significant pharmacological effects on these tissues. The EC50 values of bombesin-OS for bladder, uterus and ileum, were 10.8 nM, 33.64 nM, and 12.29 nM, respectively. Furthermore, compared with bombesin-OS, bombesin-PE showed similar contractile activity on ileum smooth muscle and uterus smooth muscle, but had a higher potency on bladder smooth muscle. The EC50 value of bombesin-OS for bladder was around 1000-fold less than that of bombesin-PE. This suggests that bombesin-OS and bombesin-PE have unique binding properties to their receptors. The precursor of bombesin-OS was homologous with that of a bombesin-like peptide, odorranain-BLP-5, and bombesin-PE belongs to the ranatensin subfamily. We identified the structure of bombesin-OS and bombesin-PE, two homologues peptides whose actions may provide a further clue in the classification of ranid frogs, also in the provision of new drugs for human health

Auxin response factor 6A regulates photosynthesis, sugar accumulation, and fruit development in tomato.

Auxin response factors (ARFs) are involved in auxin-mediated transcriptional regulation in plants. In this study, we performed functional characterization of SlARF6A in tomato. SlARF6A is located in the nucleus and exhibits transcriptional activator activity. Overexpression of SlARF6A increased chlorophyll contents in the fruits and leaves of tomato plants, whereas downregulation of SlARF6A decreased chlorophyll contents compared with those of wild-type (WT) plants. Analysis of chloroplasts using transmission electron microscopy indicated increased sizes of chloroplasts in SlARF6A-overexpressing plants and decreased numbers of chloroplasts in SlARF6A-downregulated plants. Overexpression of SlARF6A increased the photosynthesis rate and accumulation of starch and soluble sugars, whereas knockdown of SlARF6A resulted in opposite phenotypes in tomato leaves and fruits. RNA-sequence analysis showed that regulation of SlARF6A expression altered the expression of genes involved in chlorophyll metabolism, photosynthesis and sugar metabolism. SlARF6A directly bound to the promoters of SlGLK1, CAB, and RbcS genes and positively regulated the expression of these genes. Overexpression of SlARF6A also inhibited fruit ripening and ethylene production, whereas downregulation of SlARF6A increased fruit ripening and ethylene production. SlARF6A directly bound to the SAMS1 promoter and negatively regulated SAMS1 expression. Taken together, these results expand our understanding of ARFs with regard to photosynthesis, sugar accumulation and fruit development and provide a potential target for genetic engineering to improve fruit nutrition in horticulture crops

Co-expression Network Analysis Identifies Four Hub Genes Associated With Prognosis in Soft Tissue Sarcoma

Background: Soft tissue sarcomas (STS) are heterogeneous tumors derived from mesenchymal cells that differentiate into soft tissues. The prognosis of patients who present with an STS is influenced by the regulation of a complex gene network.Methods: Weighted gene co-expression network analysis (WGCNA) was performed to identify gene modules associated with STS (Samples = 156).Results: Among the 11 modules identified, the black and blue modules were highly correlated with STS. However, using preservation analysis, the black module demonstrated low preservation, therefore the blue module was chosen as the module of interest. Furthermore, a total of 20 network hub genes were identified in the blue module, 12 of which were also hub nodes in the protein-protein interaction network of the module genes. Following additional verification, 4 of 12 genes (RRM2, BUB1B, CENPF, and KIF20A) demonstrated poorer overall survival and disease-free survival rate in the test datasets. In addition, gene set enrichment analysis (GSEA) demonstrated that samples with a high level of blue module eigengene (ME) were enriched in cell cycle and metabolism associated signaling pathways.Conclusion: In summary, co-expression network analysis identified four hub genes associated with prognosis for STS, which may diminish the prognosis by influencing cell cycle and metabolism associated signaling pathways

pH-Responsive Dual Drug-Loaded Nanocarriers Based on Poly (2-Ethyl-2-Oxazoline) Modified Black Phosphorus Nanosheets for Cancer Chemo/Photothermal Therapy

Synergistic cancer therapy, such as those combining chemotherapeutic and photothermal methods, has stronger treatment effect than that of individual ones. However, it is challenging to efficiently deliver nanocarriers into tumor cells to elevate intracellular drug concentration. Herein, we developed an effective pH-responsive and dual drug co-delivery platform for combined chemo/photothermal therapy. An anticancer drug doxorubicin (DOX) was first loaded onto the surface of black phosphorus (BP). With poly(2-ethyl-2-oxazoline) (PEOz) ligand conjugated onto the polydopamine (PDA) coated BP nanosheets, targeted long circulation and cellular uptake in vivo was significantly improved. With another anticancer drug bortezomib (BTZ) loaded onto the surface of the nanocapsule, the platform can co-deliver two different drugs. The surface charge of the nanocapsule was reversed from negative to positive at the tumor extracellular pH (∼6.8), ionizing the tertiary amide groups along the PEOz chain, thus facilitating the cell internalization of the nanocarrier. The cytotoxicity therapeutic effect of this nanoplatform was further augmented under near-infrared laser irradiation. As such, our DOX-loaded BP@PDA-PEOz-BTZ platform is very promising to synergistic cancer therapy

Eco-friendly synthesis of self-supported N-doped Sb2S3-carbon fibers with high atom utilization and zero discharge for commercial full lithium-ion batteries

Antimony trisulfide (Sb2S3) is a prospective electrode material for lithium-ion batteries (LIBs) because of its thermal stability, low price, and high specific capacity. However, the commercialization of Sb2S3 as an anode material is greatly hindered by its poor electronic conductivity and massive volume variation during charge/discharge cycles. Moreover, growing demand in reducing greenhouse gas emission requires the material preparation process to be pollution free and highly energy efficient. Herein, we introduce, for the first time, an eco-friendly and highly efficient one-step annealing method to construct a three-dimensional (3D) flexible conductive network and buffer matrix for N-doped Sb2S3-carbon fibers (NSSCs) as a high-performance anode. It is assembled by mixing sulfur and antimony in the atomicity level with a stoichiometric ratio as the electrospinning precursor and then annealed in a sealed quartz tube to assure the high atom utilization of nitrogen and sulfur. Benefiting from the 3D structure and compositional advantages, the NSSC electrode with improved conductivity and carbon buffer matrix exhibits superior Li-storage performance. As a result, this work not only promotes the commercialization of antimony trisulfide but also points out a general eco-friendly method, which can be widely applied to synthesize a variety of flexible metal sulfides and metal nitrides with high atom utilization and zero discharge

The effect of mixed La-Y doping on water resistance of phosphate glass

In this work, the effect of mixed La-Y doping on the water resistance of xLa2O3–(16-x)Y2O3–8Al2O3–10Na2O–66P2O5 (x = 0, 4, 8, 12, 16 mol%) glasses was studied. The glass structure, glass transition temperature (Tg), dc conductivity (σdc) and water resistance of glass were respectively characterized by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimeter (DSC), electrochemical workstation and water resistance test. The results show that with the gradual replacement of Y2O3 by La2O3, the value of Q(2) (Q2 content as a percentage of the sum of Q1 and Q2 contents in glass structure) and water resistance characterized by mass loss per unit surface area indicate strong “mixed rare earth effect”. It is obvious that the change of glass structure causes water resistance of glass to vary nonlinearly and exhibit a positive deviation from linearity. The results can provide some useful information for tailoring the chemical durability of glass by mixed rare earth doping

CAP interacts with cytoskeletal proteins and regulates adhesion‐mediated ERK activation and motility

Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/102140/1/emboj7601406-sup-0001.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/102140/2/emboj7601406.pd