Cross-Modal Contrastive Pre-training for Few-Shot Skeleton Action Recognition

This paper proposes a novel approach for few-shot skeleton action recognition that comprises of two stages: cross-modal pre-training of a skeleton encoder, followed by fine-tuning of a cosine classifier on the support set. The pre-training and fine-tuning approach has been demonstrated to be more effective for handling few-shot tasks compared to utilizing more intricate meta-learning methods. However, its success relies on the availability of a large-scale training dataset, which yet is difficult to obtain. To address this challenge, we introduce a cross-modal pre-training framework based on Bootstrap Your Own Latent (BYOL), which considers skeleton sequences and their corresponding videos as augmented views of the same action in different modalities. By utilizing a simple regression loss, the framework is able to transfer robust and high-quality vision-language representations to the skeleton encoder. This allows the skeleton encoder to gain a comprehensive understanding of action sequences and benefit from the prior knowledge obtained from a vision-language pre-trained model. The representation transfer enhances the feature extraction capability of the skeleton encoder, compensating for the lack of large-scale skeleton datasets. Extensive experiments on the NTU RGB+D, NTU RGB+D 120, PKU-MMD, NW-UCLA, and MSR Action Pairs datasets demonstrate that our proposed approach achieves state-of-the-art performances for few-shot skeleton action recognition

A One-Dimensional Dynamic Constitutive Modeling of Ethylene Vinyl Acetate (EVA) Foam

Ethylene vinyl acetate copolymer (EVA) is good for impact protection and energy absorption, and belongs to rate sensitive-dependent materials. This study aimed to investigate the influence of increased strain rate and the presence of entrapped air on the enhancement of foam material strength. The compression deformation behavior of EVA foams containing a microporous structure was extensively investigated over different strain rates of 0.0017/s, 0.033/s, and 0.17/s, where each test was conducted at a constant compression velocity. A one-dimensional dynamic constitutive model was established to describe the large deformation response of EVA to different strain rates. The model included two components, the material action part and the air pressure part. Quasi-static and dynamic compression tests were used to determine the constitutive relations of three parameters, a1, a2, and the leaking rate δ·. The samples with EVA foams at different strain rates were fitted using ORIGIN software, and the constitutive model parameters were obtained. It was found that the ratio of the air leaking rate to the strain rate gradually decreases, causing air within the EVA to be trapped in the cells rather than escaping in a timely manner with increasing strain rates

An Assessment of the Security of China’s Natural Gas Supply System Using Two Network Models

In the context of climate change, natural gas is becoming increasingly important for low-carbon development in China. The gap between the demand and supply of natural gas, domestically, and China’s high dependence on foreign sources, highlights the importance of ensuring a secure system for supplying natural gas in the country. This study applied ecological network analysis, a powerful systems-oriented method, to simulate interactions between different nodes of the natural gas supply system and to evaluate the system’s security level. Two network models were constructed at the regional and national layers, respectively, by dividing external natural gas suppliers into multiple regions and countries. These models were used to evaluate the overall security level and related characteristics of China’s natural gas supply system from 2000 to 2012. The results showed stable improvement in the system’s security during this period. With the exceptions of some specific indicators (e.g., the mutualism index (MI)), analyses of network information and structure yielded the mostly similar results for the two models. In conclusion, a regional layer (RL) network model is considered more economical than a national layer (NL) model for evaluating the overall security of China’s natural gas supply system, especially when available data are limited

Comparative efficacy of vasoactive medications in patients with septic shock: a network meta-analysis of randomized controlled trials

Abstract Background Catecholamines, especially norepinephrine, are the most frequently used vasopressors for treating patients with septic shock. During the recent decades, terlipressin, vasopressin V1A agonist, and even Ca2+ sensitizer were increasingly used by physicians. The aim of this study is to compare the efficacy of such different kinds of vasoactive medications on mortality among patients with septic shock. Methods Relevant randomized controlled trials were identified by searching PubMed, Embase, Web of Science, and the Cochrane Central Register of Controlled Trials updated to February 22, 2018. A network meta-analysis was performed to evaluate the effect of different types of vasoactive medications. The primary outcome was 28-day mortality. Intensive care unit (ICU) mortality, hospital and ICU length of stay (LOS), and adverse events were also assessed. Results A total of 43 trials with 5767 patients assessing 17 treatment modalities were included. Treatments ranking based on surface under the cumulative ranking curve values from largest to smallest were NE/DB 85.9%, TP 75.1%, NE/EP 74.6%, PI 74.1%, EP 72.5%, VP 66.1%, NE 59.8%, PE 53.0%, DA 42.1%, DX 38.2%, SP 27.0%, PA 24.3%, EX 22.8%, LE 21.5%, and DB 13.3% for 28-day mortality. Treatments ranking for ICU mortality were TP/NE 86.4%, TP 80.3%, TP/DB/NE 65.7%, VP/NE 62.8%, NE 57.4%, VP 56.5%, PE 48.4%, DA 33.0%, PA 27.5%, LE 22.1%, and DB 9.9%. The incidence of myocardial infarction was reported with NE/EP 3.33% (n = 1 of 30), followed by EP 3.11% (n = 5 of 161), and then VP 3.10% (n = 19 of 613), NE 3.03% (n = 43 of 1417), DA 2.21% (n = 19 of 858), NE/DB 2.01% (n = 4 of 199), LE 1.16% (n = 3 of 258), and PA 0.39% (n = 1 of 257). The incidence of arrhythmia was reported with DA 26.01% (n = 258 of 992), followed by EP 22.98% (n = 37 of 161), and then NE/DB 20.60% (n = 41 of 199), NE/EP 20.0% (n = 6 of 30), NE 8.33% (n = 127 of 1525), LE 5.81% (n = 15 of 258), PA 2.33% (n = 6 of 257), and VP 1.67% (n = 10 of 600). Conclusions The use of norepinephrine plus dobutamine was associated with lower 28-day mortality for septic shock, especially among patients with lower cardiac output

Immuno-protective vesicle-crosslinked hydrogel for allogenic transplantation

Abstract The longevity of grafts remains a major challenge in allogeneic transplantation due to immune rejection. Systemic immunosuppression can impair graft function and can also cause severe adverse effects. Here, we report a local immuno-protective strategy to enhance post-transplant persistence of allografts using a mesenchymal stem cell membrane-derived vesicle (MMV)-crosslinked hydrogel (MMV-Gel). MMVs are engineered to upregulate expression of Fas ligand (FasL) and programmed death ligand 1 (PD-L1). The MMVs are retained within the hydrogel by crosslinking. The immuno-protective microenvironment of the hydrogel protects allografts by presenting FasL and PD-L1. The binding of these ligands to T effector cells, the dominant contributors to graft destruction and rejection, results in apoptosis of T effector cells and generation of regulatory T cells. We demonstrate that implantation with MMV-Gel prolongs the survival and function of grafts in mouse models of allogeneic pancreatic islet cells and skin transplantation

Endophytic Bacillus altitudinis Q7 from Ginkgo biloba inhibits the growth of Alternaria alternata in vitro and its inhibition mode of action

The study was focussed on the inhibitory mechanism associated with the ability of an endophytic bacterium - Bacillus altitudinis Q7, obtained from Ginkgo biloba, to inhibit the growth of Alternaria alternata in vitro. A fungus, identified as Alternaria alternata was isolated from the rotten part of an apple. One of the endophytes was identified as Bacillus altitudinis Q7. Effect of Bacillus altitudinis Q7 on Alternaria alternata was characterized by measuring membrane permeability and lipid peroxidation. Antioxidant enzymes in Alternaria alternata were determined before and after exposure to Bacillus altitudinis Q7. Results indicated that cell membranes in Alternaria alternata were damaged, lipid peroxidation was enhanced, and superoxide dismutase, peroxidase, and polyphenol oxidase were significantly inhibited. Content of lipopeptides produced by Bacillus altitudinis Q7 was higher than other metabolites. The FTIR spectra revealed that the prepared antibacterial lipopeptides is a cyclic lipopeptides. The effect of lipopeptides produced by Bacillus altitudinis Q7 at 2 mg/mL against Alternaria alternata in vitro reached 83.2%. The lipopeptide-treated group showed the same trend as Q7 fermentation broth in inhibition mode of action. Moreover, the utilization of proteins and sugars during culturing of Alternaria alternata decreased when adding lipopeptides to the growth medium. Bacillus altitudinis Q7 from Ginkgo biloba significantly inhibited the growth of Alternaria alternata and is a very promising biocontrol strain against Alternaria alternata. The study of endophytic bacteria and its metabolites is being done to identify biological control alternatives. The results provide a theoretical basis for understanding their antagonistic properties

Numerical simulation of cyclic performance of compressed carbon dioxide energy storage system in aquifer

The boom of renewable energy has been overshadowed by two problems: the intermittency and volatility of such energy. Largescale complementary energy storage has been required to solve these problems. This paper proposes a compressed CO2 energy storage system in aquifer (CCES-A), aiming to storage energy efficiently at a low cost. Firstly, the feasibility of compressing CO2 in the aquifer had been proved through numerical simulation, and the CO2 compression in the aquifer had been emulated by a wellbore-reservoir coupling model. The operation of the CCES-A had been divided into the establishment stage of the initial airbag, and the cyclic stage of energy storage and release. The proposed wellbore-reservoir coupling model had been applied to analyze the wellhead pressure, energy flow and energy recovery rate of weekly, monthly, and seasonal cycles, as well as the energy recovery efficiency at different injection temperatures. The simulation results showed that under the three cycles, the wellhead pressure increased with the number of cycles. The energy flow and energy recovery efficiency decreased with the growing the number of cycles. The energy recovery became more efficient with the rise of the injection temperature