Understanding the Robustness of Skeleton-based Action Recognition under Adversarial Attack

Action recognition has been heavily employed in many applications such as autonomous vehicles, surveillance, etc, where its robustness is a primary concern. In this paper, we examine the robustness of state-of-the-art action recognizers against adversarial attack, which has been rarely investigated so far. To this end, we propose a new method to attack action recognizers that rely on 3D skeletal motion. Our method involves an innovative perceptual loss that ensures the imperceptibility of the attack. Empirical studies demonstrate that our method is effective in both white-box and black-box scenarios. Its generalizability is evidenced on a variety of action recognizers and datasets. Its versatility is shown in different attacking strategies. Its deceitfulness is proven in extensive perceptual studies. Our method shows that adversarial attack on 3D skeletal motions, one type of time-series data, is significantly different from traditional adversarial attack problems. Its success raises serious concern on the robustness of action recognizers and provides insights on potential improvements.Comment: Accepted in CVPR 2021. arXiv admin note: substantial text overlap with arXiv:1911.0710

Synthesis and Properties of La1−x_{1-x}Srx_xNiO3_3 and La1−x_{1-x}Srx_xNiO2_2

Superconductivity has been realized in films of La$_{1-x}$Sr$_x$NiO$_2$. Here we report synthesis and characterization of polycrystalline samples of La$_{1-x}$Sr$_x$NiO$_3$ and La$_{1-x}$Sr$_x$NiO$_2$ ($0\le x\le 0.2$). Magnetization and resistivity measurements reveal that La$_{1-x}$Sr$_x$NiO$_3$ are paramagnetic metals and La$_{1-x}$Sr$_x$NiO$_2$ exhibit insulating behavior. Superconductivity is not detected in bulk samples of La$_{1-x}$Sr$_x$NiO$_2$. The absence of superconductivity in bulk La$_{1-x}$Sr$_x$NiO$_2$ may be due to the generation of hydroxide during reduction or a small amount of nickel impurities. The effect of interface in films of La$_{1-x}$Sr$_x$NiO$_2$ may also play a role for superconductivity.Comment: 9 pages, 4 figure

Construction and validation of a predictive risk model for nosocomial infections with MDRO in NICUs: a multicenter observational study

ObjectivesThis study aimed to construct and validate a predictive risk model (PRM) for nosocomial infections with multi-drug resistant organism (MDRO) in neonatal intensive care units (NICUs), in order to provide a scientific and reliable prediction tool, and to provide reference for clinical prevention and control of MDRO infections in NICUs.MethodsThis multicenter observational study was conducted at NICUs of two tertiary children’s hospitals in Hangzhou, Zhejiang Province. Using cluster sampling, eligible neonates admitted to NICUs of research hospitals from January 2018 to December 2020 (modeling group) or from July 2021 to June 2022 (validation group) were included in this study. Univariate analysis and binary logistic regression analysis were used to construct the PRM. H-L tests, calibration curves, ROC curves and decision curve analysis were used to validate the PRM.ResultsFour hundred and thirty-five and one hundred fourteen neonates were enrolled in the modeling group and validation group, including 89 and 17 neonates infected with MDRO, respectively. Four independent risk factors were obtained and the PRM was constructed, namely: P = 1/ (1+ e−X), X = −4.126 + 1.089× (low birth weight) +1.435× (maternal age ≥ 35 years) +1.498× (use of antibiotics >7 days) + 0.790× (MDRO colonization). A nomogram was drawn to visualize the PRM. Through internal and external validation, the PRM had good fitting degree, calibration, discrimination and certain clinical validity. The prediction accuracy of the PRM was 77.19%.ConclusionPrevention and control strategies for each independent risk factor can be developed in NICUs. Moreover, clinical staff can use the PRM to early identification of neonates at high risk, and do targeted prevention to reduce MDRO infections in NICUs

Single crystal growth and superconductivity in RbNi2_2Se2_2

We report the synthesis and characterization of RbNi$_2$Se$_2$, an analog of the iron chalcogenide superconductor Rb$_x$Fe$_2$Se$_2$, via transport, angle resolved photoemission spectroscopy, and density functional theory calculations. A superconducting transition at $T_{c}$ = 1.20 K is identified. In normal state, RbNi$_2$Se$_2$ shows paramagnetic and Fermi liquid behaviors. A large Sommerfeld coefficient yields a heavy effective electron mass of $m^{*}\approx6m_{e}$. In the superconducting state, zero-field electronic specific-heat data $C_{es}$ can be described by a two-gap BCS model, indicating that RbNi$_2$Se$_2$ is a multi-gap superconductor. Our density functional theory calculations and angle resolved photoemission spectroscopy measurements demonstrate that RbNi$_2$Se$_2$ exhibits relatively weak correlations and multi-band characteristics, consistent with the multi-gap superconductivity.Comment: 7 pages, 4 figure

“Mn-locking” effect by anionic coordination manipulation stabilizing Mn-rich phosphate cathodes

High-voltage cathodes with high power and stable cyclability are needed for high-performance sodium-ion batteries. However, the low kinetics and inferior capacity retention from structural instability impede the development of Mn-rich phosphate cathodes. Here, we propose light-weight fluorine (F) doping strategy to decrease the energy gap to 0.22 eV from 1.52 eV and trigger a “Mn-locking” effect—to strengthen the adjacent chemical bonding around Mn as confirmed by density functional theory calculations, which ensure the optimized Mn ligand framework, suppressed Mn dissolution, improved structural stability and enhanced electronic conductivity. The combination of in situ and ex situ techniques determine that the F dopant has no influence on the Na+ storage mechanisms. As a result, an outstanding rate performance up to 40C and an improved cycling stability (1000 cycles at 20C) are achieved. This work presents an effective and widely available light-weight anion doping strategy for high-performance polyanionic cathodes

D-dimer to lymphocyte ratio can serve as a potential predictive and prognostic value in colorectal cancer patients with liver metastases

Abstract Background The intent of this research was to generate and investigate the D-dimer to lymphocyte ratio (DLR) capacity to forecast the risk and prognosis of colorectal cancer liver metastases (CRCLM). Methods From January 2010 to December 2019, 177 clinicopathologically confirmed colorectal cancer (CRC) patients (89 in the control group and 88 in the experimental group) were identified at the Affiliated Cancer Hospital of Guangxi Medical University. Multivariate Cox regression analysis was used to screen independent predictive diagnostic and prognostic factors of liver metastasis in CRC, and receiver operating characteristic (ROC) curves and Kaplan‒Meier (K‒M) curves were established to analyze the diagnostic and predictive prognostic efficacy of the DLR in the development of CRCLM. Results Patients with CRCLM had higher DLR levels and D-dimer levels in their blood, with statistically significant differences (p < 0.001). DLR might be employed as a predictor for the development of CRCLM, according to ROC curve research (sensitivity 0.670, specificity 0.775, area under the curve 0.765). D-dimer, lymphocyte count CEA, CA125, and CA199 were not linked to prognosis in patients with CRCLM in Cox regression analysis of dichotomous variables. In contrast, DLR level was a possible risk factor for the prognosis of patients with CRCLM (HR = 2.108, p = 0.047), and age, T stage, and DLR level (DLR < 0.4) were connected with the prognosis of patients with CRCLM (p < 0.05). Conclusion DLR serves as a risk indicator for the development of CRCLM

Evaluating Fouling Control and Energy Consumption in a Pilot-Scale, Low-Energy POREFLON Non-Aerated Membrane Bioreactor (LEP-N-MBR) System at Different Frequencies and Amplitudes

Continual aeration, a fouling control strategy that causes high energy consumption, is the major obstacle in the deployment of membrane bioreactors (MBRs) for wastewater treatment. In recent years, a technology has been developed which adopts mechanical reciprocity for membrane vibration, and it has been proven efficient for membrane scouring, as well as for saving energy: the low-energy POREFLON non-aerated membrane bioreactor (LEP-N-MBR). In this study, a pilot-scale LEP-N-MBR system was designed, established, and operated at various frequencies and amplitudes, and with various membrane models, so as to evaluate energy usage and membrane fouling. The results showed that a slower TMP rise occurred when the frequency and amplitude were set to 0.5 Hz and 10 cm, respectively. Under a suitable frequency and amplitude, the TMP increasing rate of model B (sealed only with epoxy resin) was slower than that of model A (sealed with a combination of polyurethane and epoxy resin). The average specific energy demand (SED) of the LEP-N-MBR was 0.18 kWh&middot;m&minus;3, much lower than the aerated MBR with 0.43 kWh&middot;m&minus;3 (obtained from a previous study), indicating a significant decrease of 59.54% in the SED. However, the uneven distribution of sludge within the membrane tank indicated that the poor hydraulic mixing in the reactor may result in sludge accumulation, which requires further operational optimization. The findings of this pilot-scale study suggest that the LEP-N-MBR system is promising and effective for municipal wastewater treatment with a much lower level of energy usage. More research is needed to further optimize the operation of the LEP-N-MBR for wide application

RBM38 plays a tumor-suppressor role via stabilizing the p53-mdm2 loop function in hepatocellular carcinoma

Abstract Background Misregulation of the p53-mdm2 loop function is a major mechanism to promote hepatocellular carcinoma (HCC). RBM38, a member of the RNA recognition motif (RRM) family of RNA binding proteins (RBPs), plays a fundamental role in the posttranscriptional control of gene expression and regulatory functions in human tumors. A novel RBM38-p53-mdm2 autoregulatory feedback loop has been demonstrated. However, its mechanistic role in HCC remains unclear. Methods In the present study, we investigated the role and molecular mechanism of misregulation in the p53-mdm2 loop function by RBM38 in HCC. First we investigated the correlation of RBM38 activity and p53-mdm2 loop function in liver cancer cells and HCC tissues by western blot and quantitative RT-PCR. We then conducted functional assays to investigate the molecular roles of RBM38 in inhibiting liver cancer cells aggressiveness in vitro and suppressing tumorigenicity in vivo. Results We observed RBM38 protein expression was commonly silenced coupled with increased mdm2 and decreased wild type (wt) p53 in liver cancer cells and HCC tissues compared to the corresponding normal liver cells and adjacent liver tissues. RBM38 mRNA level was significantly lower in HCC than adjacent liver tissues, whereas mdm2 and wtp53 mRNA levels were similar between HCC and adjacent liver tissues. This implied that deactivation of RBM38 could disrupt the p53-mdm2 loop and promote HCC, even though p53 and mdm2 transcript amounts were stable. Then, we generated stable liver cancer cell lines with overexpressed RBM38 (RBM38-OE) and found that up-regulation of RBM38 could inhibit mdm2 and restore wtp53 expression. Luciferase assay shown that RBM38 destabilized the mdm2 transcript through binding to multiple AU-/U-rich elements in mdm2 3’-UTR. Furthermore, functional assays showed that ectopic expression of RBM38 could induce liver cancer cell apoptosis and senescence, inhibit proliferation and colony growth, and suppress migration and invasion in vitro. Lastly, RBM38 could suppress HCC tumorigenicity in vivo. Conclusion Our findings suggested that RBM38 may be a core contributor in stabilizing the p53-mdm2 loop function to prevent HCC, and a potential novel target to provide a therapeutic strategy for HCC by inhibiting mdm2 and rescuing p53 from inactivation

Polybrene induces neural degeneration by bidirectional Ca2+ influx-dependent mitochondrial and ER-mitochondrial dynamics

Hexadimethrine bromide (Polybrene) was once used clinically as a heparin neutralizer and has recently found use as a promoter in virus-mediated gene therapy trials and gene transfer in research. However, the potential for tissue-specific toxicity of polybrene at low doses has been ignored so far. Here, we found that after intracerebroventricular (ICV) polybrene injection, mice showed disability of movement accompanied neural death and gliosis in brain, and in human neurons, polybrene induces concentration-dependent neuritic beading and fragmentation. Mechanistically, polybrene induces a rapid voltage-dependent calcium channel (VDCC)-mediated influx of extracellular Ca2+. The elevated cytoplasmic Ca2+ activates DRP1, which leads to mitochondrial fragmentation and metabolic dysfunction. At the same time, Ca2+ influx induces endoplasmic reticulum (ER) fragmentation and tightened associations between ER and mitochondria, which makes mitochondria prone to Ca2+ overloading and ensuing permeability transition. These results reveal an unexpected neuronal toxicity of polybrene, wherein Ca2+ influx serves as a regulator for both mitochondrial dynamics and ER-mitochondrial remodeling