Composite Adversarial Attacks

Adversarial attack is a technique for deceiving Machine Learning (ML) models, which provides a way to evaluate the adversarial robustness. In practice, attack algorithms are artificially selected and tuned by human experts to break a ML system. However, manual selection of attackers tends to be sub-optimal, leading to a mistakenly assessment of model security. In this paper, a new procedure called Composite Adversarial Attack (CAA) is proposed for automatically searching the best combination of attack algorithms and their hyper-parameters from a candidate pool of \textbf{32 base attackers}. We design a search space where attack policy is represented as an attacking sequence, i.e., the output of the previous attacker is used as the initialization input for successors. Multi-objective NSGA-II genetic algorithm is adopted for finding the strongest attack policy with minimum complexity. The experimental result shows CAA beats 10 top attackers on 11 diverse defenses with less elapsed time (\textbf{6 $\times$ faster than AutoAttack}), and achieves the new state-of-the-art on $l_{\infty}$, $l_{2}$ and unrestricted adversarial attacks.Comment: To appear in AAAI 2021, code will be released late

COCO-O: A Benchmark for Object Detectors under Natural Distribution Shifts

Practical object detection application can lose its effectiveness on image inputs with natural distribution shifts. This problem leads the research community to pay more attention on the robustness of detectors under Out-Of-Distribution (OOD) inputs. Existing works construct datasets to benchmark the detector's OOD robustness for a specific application scenario, e.g., Autonomous Driving. However, these datasets lack universality and are hard to benchmark general detectors built on common tasks such as COCO. To give a more comprehensive robustness assessment, we introduce COCO-O(ut-of-distribution), a test dataset based on COCO with 6 types of natural distribution shifts. COCO-O has a large distribution gap with training data and results in a significant 55.7% relative performance drop on a Faster R-CNN detector. We leverage COCO-O to conduct experiments on more than 100 modern object detectors to investigate if their improvements are credible or just over-fitting to the COCO test set. Unfortunately, most classic detectors in early years do not exhibit strong OOD generalization. We further study the robustness effect on recent breakthroughs of detector's architecture design, augmentation and pre-training techniques. Some empirical findings are revealed: 1) Compared with detection head or neck, backbone is the most important part for robustness; 2) An end-to-end detection transformer design brings no enhancement, and may even reduce robustness; 3) Large-scale foundation models have made a great leap on robust object detection. We hope our COCO-O could provide a rich testbed for robustness study of object detection. The dataset will be available at \url{https://github.com/alibaba/easyrobust/tree/main/benchmarks/coco_o}.Comment: To appear in ICCV2023, https://github.com/alibaba/easyrobust/tree/main/benchmarks/coco_

The Lipid Handling Capacity of Subcutaneous Fat Is Programmed by mTORC2 during Development

Overweight and obesity are associated with type 2 diabetes, non-alcoholic fatty liver disease, cardiovascular disease and cancer, but all fat is not equal, as storing excess lipid in subcutaneous white adipose tissue (SWAT) is more metabolically favorable than in visceral fat. Here, we uncover a critical role for mTORC2 in setting SWAT lipid handling capacity. We find that subcutaneous white preadipocytes differentiating without the essential mTORC2 subunit Rictor upregulate mature adipocyte markers but develop a striking lipid storage defect resulting in smaller adipocytes, reduced tissue size, lipid re-distribution to visceral and brown fat, and sex-distinct effects on systemic metabolic fitness. Mechanistically, mTORC2 promotes transcriptional upregulation of select lipid metabolism genes controlled by PPARγ and ChREBP, including genes that control lipid uptake, synthesis, and degradation pathways as well as Akt2, which encodes a major mTORC2 substrate and insulin effector. Further exploring this pathway may uncover new strategies to improve insulin sensitivity.Fil: Hsiao, Wen Yu. University Of Massachussets. Medical School; Estados UnidosFil: Jung, Su Myung. University Of Massachussets. Medical School; Estados UnidosFil: Tang, Yuefeng. University Of Massachussets. Medical School; Estados UnidosFil: Haley, John A.. University Of Massachussets. Medical School; Estados UnidosFil: Li, Rui. University Of Massachussets. Medical School; Estados UnidosFil: Li, Huawei. University Of Massachussets. Medical School; Estados UnidosFil: Martinez Calejman, Camila. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Houssay. Centro de Estudios Farmacológicos y Botánicos. Universidad de Buenos Aires. Facultad de Medicina. Centro de Estudios Farmacológicos y Botánicos; Argentina. University Of Massachussets. Medical School; Estados UnidosFil: Sanchez Gurmaches, Joan. University Of Massachussets. Medical School; Estados Unidos. University of Cincinnati; Estados UnidosFil: Hung, Chien-Min. University Of Massachussets. Medical School; Estados UnidosFil: Luciano, Amelia K.. University Of Massachussets. Medical School; Estados UnidosFil: DeMambro, Victoria. University of Maine; Estados UnidosFil: Wellen, Kathryn E.. University of Pennsylvania; Estados UnidosFil: Rosen, Clifford J.. University of Maine; Estados UnidosFil: Zhu, Lihua Julie. University Of Massachussets. Medical School; Estados UnidosFil: Guertin, David A.. University Of Massachussets. Medical School; Estados Unido

The Lipid Handling Capacity of Subcutaneous Fat Is Programmed by mTORC2 during Development

Overweight and obesity are associated with type 2 diabetes, non-alcoholic fatty liver disease, cardiovascular disease and cancer, but all fat is not equal, as storing excess lipid in subcutaneous white adipose tissue (SWAT) is more metabolically favorable than in visceral fat. Here, we uncover a critical role for mTORC2 in setting SWAT lipid handling capacity. We find that subcutaneous white preadipocytes differentiating without the essential mTORC2 subunit Rictor upregulate mature adipocyte markers but develop a striking lipid storage defect resulting in smaller adipocytes, reduced tissue size, lipid re-distribution to visceral and brown fat, and sex-distinct effects on systemic metabolic fitness. Mechanistically, mTORC2 promotes transcriptional upregulation of select lipid metabolism genes controlled by PPARgamma and ChREBP, including genes that control lipid uptake, synthesis, and degradation pathways as well as Akt2, which encodes a major mTORC2 substrate and insulin effector. Further exploring this pathway may uncover new strategies to improve insulin sensitivity

Finishing the euchromatic sequence of the human genome

The sequence of the human genome encodes the genetic instructions for human physiology, as well as rich information about human evolution. In 2001, the International Human Genome Sequencing Consortium reported a draft sequence of the euchromatic portion of the human genome. Since then, the international collaboration has worked to convert this draft into a genome sequence with high accuracy and nearly complete coverage. Here, we report the result of this finishing process. The current genome sequence (Build 35) contains 2.85 billion nucleotides interrupted by only 341 gaps. It covers ∼99% of the euchromatic genome and is accurate to an error rate of ∼1 event per 100,000 bases. Many of the remaining euchromatic gaps are associated with segmental duplications and will require focused work with new methods. The near-complete sequence, the first for a vertebrate, greatly improves the precision of biological analyses of the human genome including studies of gene number, birth and death. Notably, the human enome seems to encode only 20,000-25,000 protein-coding genes. The genome sequence reported here should serve as a firm foundation for biomedical research in the decades ahead

Hierarchically structured reactors containing nanocarbons for intensification of chemical reactions

34 FigurasCarbon nanomaterials, such as carbon nanotubes, carbon nanofibers and graphene, featuring functional properties and tailored nanoscale dimensions have been widely used in different research fields, especially for catalysis and sustainable chemistry. Hierarchically structured reactors, combining nanoscopic coating carbon layers to disperse the active phase or even directly as metal-free catalysts, with controlled macroscopic shapes, have been extensively developed over the last few decades for numerous relevant catalytic processes, where mass and heat transfer is easily optimized for better catalytic performance and stability. The 3D structuration enables the full exploitation of the intrinsic activity of the catalyst and its industrial deployment without drawbacks linked with nanomaterials. In this review article, we will summarize the recent developments involved in the field of hierarchically structured reactors, i.e. monoliths, foam and other materials, containing carbon nanomaterials. It is expected that such structured reactors will receive high scientific and industrial interest in the future not only in the field of catalysis but also in those linked with wastewater purification or aerosol filtration processes. It will also be evidenced how hierarchically structured materials have contributed to the intensification of catalytic processes compared to conventional reactors, thus paving the way to the enhancement of other chemical reactions and their industrial deployment.Dr Y. F. Liu and Prof. D. S. Su acknowledge the financial support by the NSFC of China (No. 91645117, 21606243 and 21473223). The European Commission is acknowledged for the funding through the projects MONACAT and FREECATS.Peer reviewe

A promising composite solid electrolyte of garnet-type LLZTO and succinonitrile in thermal polyurethane matrix for all-solid-state lithium-ion batteries

For solid-state electrolyte in lithium-ion batteries, high crystal boundary impedance leads to tough electrolyte-electrode interfacial issues. Here, we introduce garnet Li6.4La3Zr1.4Ta0.6O12 (LLZTO) nanoparticles and succinonitrile (SN) into thermal polyurethane (TPU) to fabricate a composite solid-state electrolyte (TPU/LLZTO/SN), achieving high ionic conductivity of 6.452 × 10−4 S cm−1. The TPU polymer with specific soft and hard segments allows lithium ions fast transport and holds good mechanical strength as the electrolyte matrix. The ionic conductor LLZTO further improves the ionic conductivity and mechanical property of the composite electrolyte membrane. Additional SN supplies the electrolyte’ wide electrochemical stabilization window, and enhances the metallic lithium compatibility of the TPU matrix. As a result, the as prepared TPU/LLZTO/SN electrolyte presents high lithium ions transference number of 0.64, and also good mechanical property

Self-Propagated Flaming Synthesis of Highly Active Layered CuO-delta-MnO2 Hybrid Composites for Catalytic Total Oxidation of Toluene Pollutant

A new self-propagated flaming (SPF) technique was applied to the synthesis of highly active layered CuO-delta-MnO2 hybrid composites, for the de-polluting catalytic total oxidation of gaseous toluene vapor. Other transition metal oxide-doped MnO2 hybrid composites were also successfully prepared and investigated, ensuring a feasible strategy for the fabrication of various layered MOx-delta-MnO2 (M=Co, Ni, or Zn) hybrids. By changing the molar ratio of the precursors (KMnO4 and acetate salt) and the type of transition metal oxide introduced, it is possible to control the crystal structure and reducibility of the sheetlike hybrid composites as well as the catalytic activity for the total oxidation of toluene. The catalyst sample (CuO-delta-MnO2) with a Mn/Cu molar ratio of 10:1 exhibited the highest catalytic performance, with a lower reaction temperature of 300 degrees C for complete toluene removal, which was comparable to the reaction temperature for total toluene conversion by the Pt-based catalyst. The SPF technique provides an approach for developing highly efficient catalysts for the complete removal of volatile organic compounds, by allowing the facile and energy-saving fabrication of large quantities of layered CuO-delta-MnO2 hybrids

Insight into the chemical adsorption properties of CO molecules supported on Au or Cu and hybridized Au-CuO nanoparticles

Although nanosized Au clusters have been well developed for many applications, fundamental understanding of their adsorption/activation behaviors in catalytic applications is still lacking, especially when other elements provide promotion or hybridization functions. Au hybridized with Cu element is a highly investigated system; Cu is in the same element group as Au and thus displays similar physicochemical properties. However, their hybrids are not well understood in terms of their chemical states and adsorption/ activation properties. In this work, typical gamma-Al2O3-supported Au and CuO as well as Au-CuO nanoparticles were prepared and characterized to explore their adsorption/activation properties in depth using CO as a probe molecule using advanced techniques, such as XPS, HR-TEM, temperature programmed experiments and operando DRIFT combined with mass spectra. It was found that gold and copper can both act as active sites during CO adsorption and activation. The CO-TPD and operando DRIFT results also revealed that CO molecules were able to react with surface oxygenated species, resulting in the direct formation of CO2 over the three samples in the absence of gaseous O-2. The gold step sites (Austep) participated more readily in the reaction, especially under gaseous O-2-free conditions. During adsorption, CO molecules were more preferentially adsorbed on Au-0 sites at lower temperature comparing with those on the Cu-0 sites. However, competitive adsorption occurred between CO adsorbed on Au-0 and Cu-0 with increased reaction temperature, and the synergy between the Au and Cu compositions was too strong to suppress the adsorption and activation of the CO molecules. The dynamic adsorption equilibrium over 120 degrees C to 200 degrees C resulted in the appearance of a hysteresis performance platform