Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 20 de 940
Filtrar
1.
Artigo em Inglês | MEDLINE | ID: mdl-34739382

RESUMO

Meta reinforcement learning (meta-RL) is a promising technique for fast task adaptation by leveraging prior knowledge from previous tasks. Recently, context-based meta-RL has been proposed to improve data efficiency by applying a principled framework, dividing the learning procedure into task inference and task execution. However, the task information is not adequately leveraged in this approach, thus leading to inefficient exploration. To address this problem, we propose a novel context-based meta-RL framework with an improved exploration mechanism. For the existing exploration and execution problem in context-based meta-RL, we propose a novel objective that employs two exploration terms to encourage better exploration in action and task embedding space, respectively. The first term pushes for improving the diversity of task inference, while the second term, named action information, works as sharing or hiding task information in different exploration stages. We divide the meta-training procedure into task-independent exploration and task-relevant exploration stages according to the utilization of action information. By decoupling task inference and task execution and proposing the respective optimization objectives in the two exploration stages, we can efficiently learn policy and task inference networks. We compare our algorithm with several popular meta-RL methods on MuJoco benchmarks with both dense and sparse reward settings. The empirical results show that our method significantly outperforms baselines on the benchmarks in terms of sample efficiency and task performance.

2.
J Hazard Mater ; : 127621, 2021 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-34763923

RESUMO

The infections caused by antibiotic resistant bacteria (ARB) can lead to higher medical costs, prolonged hospital stays, and increased mortality compared to bacteria that are susceptible to antibiotics. Challenges exist in quantifying the potential risk/burden associated with antimicrobial resistance (AMR) as there is a lack of dose-response models available for pathogens which are resistant to antibiotics, in addition to the fact that very little is known regarding the health risks posed by antibiotic resistant genes (ARG). In this paper, we proposed a new modelling framework to evaluate the relative burden of AMR in natural aquatic environments. With this framework, an AMR burden score for each sample was calculated based on burden coefficients assigned for each ARB and ARG, as well as weighted burdens for the separate ARBs and ARGs components. The method developed in this study was applied to assess the relative burden of AMR in local aquatic environments with different land uses at different seasons. The collected filed data were used to verify the applicability of the proposed relative burden assessment method. Through the established method, the spatial and temporal hotspots of AMR were identified, which could provide useful information to agencies for better control and management of AMR emergence in natural aquatic environments.

3.
BMJ Open ; 11(11): e049157, 2021 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-34753754

RESUMO

OBJECTIVES: The purpose of this study was to investigate the incidence of vertebral and hip fractures in the older people and to clarify the relationship between these fractures and body mass index (BMI) along with the impact of sex differences.DesignThis was a retrospective cohort study.SettingWe used administrative claims data between April 2010 and March 2018. PARTICIPANTS: Older people aged ≥75 years who underwent health examinations in 2010 and were living in the Fukuoka Prefecture, Japan were included in the study. A total of 24 691 participants were included; the mean age was 79.4±4.3 years, 10 853 males and 13 838 females, and an the mean duration of observation was 6.9±1.6 years. PRIMARY AND SECONDARY OUTCOME MEASURES: We estimated the incidence of vertebral and hip fractures by BMI category (underweight: <18.5 kg/m2, normal weight: 18.5-24.9 kg/m2, overweight and obese: ≥25.0 kg/m2) using a Kaplan-Meier curve in males and females and determined fracture risk by sex using Cox proportional hazards regression analyses. RESULTS: The incidence of vertebral and hip fractures was 16.8% and 6.5%, respectively. The cumulative incidence of vertebral and hip fracture at the last observation (8 years) in each BMI groups (underweight/normal weight/overweight and obese) estimated using the Kaplan-Meier curve was 14.7%/10.4%/9.0% in males and 24.9%/23.0%/21.9% in females, and 6.3%/2.9%/2.4% in males and 14.1%/9.0%/8.1% in females, respectively, and both fractures were significantly higher in underweight groups regardless of sex. Multivariable Cox proportional hazards models showed that underweight was a significant risk factor only in males for vertebral fractures and in both males and females for hip fractures. CONCLUSION: Underweight was associated with fractures in the ageing population, but there was a sex difference in the effect for vertebral fractures.

4.
Thorac Cancer ; 2021 Nov 06.
Artigo em Inglês | MEDLINE | ID: mdl-34741494

RESUMO

BACKGROUND: The aim of the study was to assess the efficacy and side-effects of intrapleural treatment in non-small cell lung cancer (NSCLC) patients with malignant pleural effusions (MPEs). METHODS: The medical records of NSCLC patients with MPEs diagnosed in four Chinese hospitals from October 2014 to December 2019 were searched. The Kaplan-Meier method is used to calculate median overall survival (MOS) and subgroup analyses are done. RESULTS: A total of 285 patients were evaluated; 81.1% of patients received intrapleural treatment, and no patients received talc pleurodesis. MOS of the whole cohort was 21 months. Patients were divided into three groups: erythromycin group (EG; intrapleural treatment with drugs and erythromycin); intrathoracic treatment group (ITG; intrapleural treatment with drugs); control group (CG; no drug treatment in the pleural cavity). The MOS of patients in the EG, ITG and CG was 20, 22, and 19 months, respectively. Among patients who received only chemotherapy as systemic therapy, the MOS of intrathoracic administration group (IAG; i.e., EG and ITG) was longer than that of CG (12 vs. 6 months; p = 0.034), and the MOS of patients with a ratio of carcinoembryonic antigen in pleural effusion (PE-CEA): CEA in blood (B-CEA) ≤1 is worse than that of patients with a ratio >1 (4 vs. 12 months, p = 0.021) and that of CG (4 vs. 6 months, p = 0.442). CONCLUSIONS: Intrapleural treatment can prolong the survival of NSCLC patients with MPE who do not receive targeted treatment or who only receive chemotherapy. The PE-CEA: B-CEA ratio can be used to predict the efficacy if intrapleural treatment is indicated.

5.
ACS Biomater Sci Eng ; 2021 Nov 30.
Artigo em Inglês | MEDLINE | ID: mdl-34847318

RESUMO

A kind of novel multifunctional modules based on zinc(II)-coordinative cyclen has been developed, which is utilized to modify low molecular weight polyethylenimine (LMWPEI) obtaining high-performance DNA vectors. A series of in vitro experiments were carried out to explore the performance of the module in improving the key process of gene transfection, such as DNA condensation, serum resistance, cellular uptake, and endosomal escape. The results demonstrate that there is a significant synergistic effect between the functional module and PEI2.5k in the process of breaking through the key barriers of gene transfection. The optimal Zn-PCD mediates 160-fold higher gluciferase activity than commercial transfection reagents PEI25k in ADSC stem cells with more than 90% cell viability and achieves excellent transfection efficiency in diverse cell types, for instance, HepG2 cells, 293T cells, and 293F suspension cells.

6.
J Surg Res ; 270: 547-554, 2021 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-34826690

RESUMO

BACKGROUND: The clinical characterization of the biological status of complex wounds remains a considerable challenge. Digital photography provides a non-invasive means of obtaining wound information and is currently employed to assess wounds qualitatively. Advances in machine learning (ML) image processing provide a means of identifying "hidden" features in pictures. This pilot study trains a convolutional neural network (CNN) to predict gene expression based on digital photographs of wounds in a canine model of volumetric muscle loss (VML). MATERIALS AND METHODS: Images of volumetric muscle loss injuries and tissue biopsies were obtained in a canine model of VML. A CNN was trained to regress gene expression values as a function of the extracted image segment (color and spatial distribution). Performance of the CNN was assessed in a held-back test set of images using Mean Absolute Percentage Error (MAPE). RESULTS: The CNN was able to predict the gene expression of certain genes based on digital images, with a MAPE ranging from ∼10% to ∼30%, indicating the presence and identification of distinct, and identifiable patterns in gene expression throughout the wound. CONCLUSIONS: These initial results suggest promise for further research regarding this novel use of ML regression on medical images. Specifically, the use of CNNs to determine the mechanistic biological state of a VML wound could aid both the design of future mechanistic interventions and the design of trials to test those therapies. Future work will expand the CNN training and/or test set, with potential expansion to predicting functional gene modules.

7.
Curr Alzheimer Res ; 2021 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-34819006

RESUMO

BACKGROUND: As the most basic material, synthetic human Amyloid-ß (1-42) (Aß42) pep- tides from different manufacturers have been widely used. Their aggregation ability is vital to the reliability, repeatability and comparability of studies on Aß42 physiology and pathology. However, it has not been evaluated and compared. OBJECTIVES: To analyze the consistency of the aggregation ability of 5 commercially available Aß42 peptides. METHODS: 5 Aß42 peptides represented as A, B, C, D and E were pretreated by HFIP. The pretreated Aß42 peptides were dissolved in Thioflavin T (ThT) solution, and their aggregation kinetics was monitored for 30 h with the aggregation kinetics test. Meanwhile, the pretreated peptides were ag- gregated in phosphate buffered saline. After aggregated for 12 h, they were detected by methods of ThT fluorescence, far-UV circular dichroism (CD), SDS-PAGE, western blot, and transmission electron microscopy (TEM), respectively. After aggregation for 8 h and 12 h, their cytotoxicity to SH-SY5Y cells was further evaluated using Cell Counting Kit-8. RESULTS: For aggregation kinetics, peptides A, C and E remained low level curves, while peptides B and D presented typical sigmoidal kinetics curves. In CD measurement, the aggregates of pep- tides B and D showed relatively high negative CD peaks with the height of -8.09 mdeg and -14.37 mdeg, while the height of peptides A, C and E was -1.04, -3.55, and -3.88. In ThT assay, relative fluorescence intensity of the aggregates of peptides B and D were 7.79 and 8.82, higher than 1.19, 1.71, and 2.70 of peptide A, C and E, respectively. In SDS-PAGE, all aggregates contained monomers and eleven polymers. Moreover, peptide B-E presented a trapezoidal distribution from dimers to trimers, and peptide A aggregated to dimers. By western blot, the bands of monomers re- mained in all aggregates. Furthermore, peptides B and D aggregated to dimers and trimers, pep- tides A and C only aggregated to dimers, and peptide E showed a strong band of trimers. By TEM, protofibrils were observed only in peptide B, while substantial spherical aggregates were formed in other peptides. Additionally, peptides B, D and E exhibited higher cytotoxicity after being aggregat- ed for 8 h, whereas peptides A, B and D presented relatively high cytotoxicity after 12-hour aggre- gation. CONCLUSION: Commercially available Aß42 peptides showed obvious differences in aggregation abil- ity, which should arouse enough attention in the field of basic study related to Aß42. The aggrega- tion ability evaluation with the various assay methods has some discrepancies, and it is highly ur- gent to establish a reasonable and uniform measurement strategy.

8.
Front Cell Dev Biol ; 9: 762651, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34733856

RESUMO

As a key transcription factor, the evolutionarily conserved tumor suppressor p53 (encoded by TP53) plays a central role in response to various cellular stresses. A variety of biological processes are regulated by p53 such as cell cycle arrest, apoptosis, senescence and metabolism. Besides these well-known roles of p53, accumulating evidence show that p53 also regulates innate immune and adaptive immune responses. p53 influences the innate immune system by secreted factors that modulate macrophage function to suppress tumourigenesis. Dysfunction of p53 in cancer affects the activity and recruitment of T and myeloid cells, resulting in immune evasion. p53 can also activate key regulators in immune signaling pathways which support or impede tumor development. Hence, it seems that the tumor suppressor p53 exerts its tumor suppressive effect to a considerable extent by modulating the immune response. In this review, we concisely discuss the emerging connections between p53 and immune responses, and their impact on tumor progression. Understanding the role of p53 in regulation of immunity will help to developing more effective anti-tumor immunotherapies for patients with TP53 mutation or depletion.

9.
Ann Vasc Surg ; 2021 Nov 11.
Artigo em Inglês | MEDLINE | ID: mdl-34775026

RESUMO

OBJECTIVES: Permanent filter placement may result in numerous complications. Filter removal is recommended if there are no risks of pulmonary embolism. This study aimed to explore the feasibility of placing a new filter when the embolized nonconical filter is removed. METHODS: This study included patients who had received a new filter between 2018 and 2019 before the nonconical filters were removed. Patient characteristics, new filter types, thrombus interception rate, filter removal rate, feasibility, and safety were analyzed retrospectively. Feasibility was defined as the successful placement of new filters and the removal of the nonconical filters. Safety was defined as the absence of symptomatic pulmonary embolism and inferior vena cava hemorrhage after removing the nonconical filters, as well as the successful removal of new filters without symptomatic pulmonary embolism. RESULTS: The average indwelling period of the nonconical filters was 29 (range, 17-30) days among the 13 patients. The removal rate of the nonconical filters was 100%. Five patients (38.5%) received new Denali filters, one (7.7%) received a new Celect filter, and 7 (53.8%) received new temporary filters. Thrombi were intercepted in 10 of the patients (76.9%). The removal rate of the replaced new filters was 100%. No rupture or shifting of the new filters occurred. No symptomatic pulmonary embolism was found after the removal of both the nonconical filters and the new filters. The patients were followed up for 3 months after the surgeries, and the inferior vena cavae of 12 (92.3%) patients were patent, and no new embolic events were found. CONCLUSIONS: Placing a new replacement filter before removal of the embolized nonconical filter may be a feasible approach to prevent pulmonary embolism. Both the nonconical filter and the new filter could be removed subsequently after the thrombi were treated.

10.
Artigo em Inglês | MEDLINE | ID: mdl-34735721

RESUMO

OBJECTIVE: To find the optimal threshold of Ki67 and evaluate its significance in predicting recurrence of stage I-II cervical cancer. METHODS: A total of 1130 patients were included after screening. Univariate and multivariate Cox regression analysis were used to select factors associated with recurrence of cervical cancer. The receiver operating characteristic (ROC) curve was used to assess the optimal threshold of Ki67. The differences of clinicopathological parameters and the survival analysis between the two groups divided based on the optimal threshold of Ki67 were compared. RESULTS: Multivariate Cox regression analysis showed that Ki67 (p < 0.001) was significant prognostic predictor for recurrence of cervical cancer. The optimal threshold of Ki67 was 42%. The recurrence-free survival (RFS) and the overall survival (OS) of cervical cancer patients in the high-Ki67 group (Ki67≥42%) were much lower than those in the low-Ki67 group (Ki67<42%) (p < 0.001, p < 0.001). Among the 380 patients with low-risk cervical cancer, the RFS and OS of patients in the high-Ki67 group were also lower than those in the low-Ki67 group (p < 0.001, p < 0.001). CONCLUSION: The Ki67 was a useful prognostic factor in patients with stage I-II cervical cancer, and the Ki67 labeling index 42.0% was optimal threshold for predicting recurrence.

11.
Sci China Life Sci ; 2021 Nov 26.
Artigo em Inglês | MEDLINE | ID: mdl-34846643

RESUMO

The changes associated with malignancy are not only in cancer cells but also in environment in which cancer cells live. Metabolic reprogramming supports tumor cell high demand of biogenesis for their rapid proliferation, and helps tumor cell to survive under certain genetic or environmental stresses. Emerging evidence suggests that metabolic alteration is ultimately and tightly associated with genetic changes, in particular the dysregulation of key oncogenic and tumor suppressive signaling pathways. Cancer cells activate HIF signaling even in the presence of oxygen and in the absence of growth factor stimulation. This cancer metabolic phenotype, described firstly by German physiologist Otto Warburg, insures enhanced glycolytic metabolism for the biosynthesis of macromolecules. The conception of metabolite signaling, i.e., metabolites are regulators of cell signaling, provides novel insights into how reactive oxygen species (ROS) and other metabolites deregulation may regulate redox homeostasis, epigenetics, and proliferation of cancer cells. Moreover, the unveiling of noncanonical functions of metabolic enzymes, such as the moonlighting functions of phosphoglycerate kinase 1 (PGK1), reassures the importance of metabolism in cancer development. The metabolic, microRNAs, and ncRNAs alterations in cancer cells can be sorted and delivered either to intercellular matrix or to cancer adjacent cells to shape cancer microenvironment via media such as exosome. Among them, cancer microenvironmental cells are immune cells which exert profound effects on cancer cells. Understanding of all these processes is a prerequisite for the development of a more effective strategy to contain cancers.

12.
Front Genet ; 12: 741323, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34630532

RESUMO

Woodhouse-Sakati syndrome (WSS, MIM 241080) is a rare neuroendocrine disease characterized by hair loss, hypogonadism, diabetes, hearing loss, and extrapyramidal syndrome, and is usually caused by mutations in the DCAF17 gene as an inherited disease. DCAF17 plays an important role in mammalian gonadal development and infertility. So far, there have been no WSS reports in China. The patient introduced in this case is from a consanguineous family. The main symptoms of the patient were alopecia and gonadal agenesis. Other symptoms such as hearing loss, intellectual disability, and hyperglycemia were remarkable, and these symptoms are often observed in WSS patients. We found a nonsense mutation in the 11th exon of the gene DCAF17 (Refseq: NM_025000) in the patient and her younger brother, which confirmed the diagnosis of WSS. The genetic results also showed that the mutation was inherited from their healthy first-cousin parents.

13.
Cancer Res ; 2021 Oct 12.
Artigo em Inglês | MEDLINE | ID: mdl-34642183

RESUMO

The relationship between cancer and autoimmunity is complex. However, the incidence of solid tumors such as melanoma has increased significantly among patients with previous or newly diagnosed systemic autoimmune disease (AID). At the same time, immune checkpoint blockade (ICB) therapy of cancer induces de novo autoinflammation and exacerbates underlying AID, even without evident anti-tumor responses. Recently, systemic lupus erythematosus (SLE) activity was found to drive myeloid-derived suppressor cell (MDSC) formation in patients, a known barrier to healthy immune surveillance and successful cancer immunotherapy. Crosstalk between MDSCs and macrophages generally drives immune suppressive activity in the tumor microenvironment. However, it remains unclear how peripheral pre-generated MDSC under chronic inflammatory conditions modulates global macrophage immune functions and the impact it could have on existing tumors and underlying lupus nephritis. Here we show that pathogenic expansion of SLE-generated MDSCs by melanoma drives global macrophage polarization and simultaneously impacts the severity of lupus nephritis and tumor progression in SLE-prone mice. Molecular and functional data showed that MDSCs interact with autoimmune macrophages and inhibit cell surface expression of CD40 and the production of IL-27. Moreover, low CD40/IL-27 signaling in tumors correlated with high TAM infiltration and ICB therapy resistance both in murine and human melanoma exhibiting active IFNγ signatures. These results suggest that preventing global macrophage reprogramming induced by MDSC-mediated inhibition of CD40/IL-27 signaling provides a precision melanoma immunotherapy strategy, supporting an original and advantageous approach to treat solid tumors within established autoimmune landscapes.

14.
Adv Sci (Weinh) ; : e2102662, 2021 Oct 29.
Artigo em Inglês | MEDLINE | ID: mdl-34716676

RESUMO

Active mechanical metamaterials (AMMs) (or smart mechanical metamaterials) that combine the configurations of mechanical metamaterials and the active control of stimuli-responsive materials have been widely investigated in recent decades. The elaborate artificial microstructures of mechanical metamaterials and the stimulus response characteristics of smart materials both contribute to AMMs, making them achieve excellent properties beyond the conventional metamaterials. The micro and macro structures of the AMMs are designed based on structural construction principles such as, phase transition, strain mismatch, and mechanical instability. Considering the controllability and efficiency of the stimuli-responsive materials, physical fields such as, the temperature, chemicals, light, electric current, magnetic field, and pressure have been adopted as the external stimuli in practice. In this paper, the frontier works and the latest progress in AMMs from the aspects of the mechanics and materials are reviewed. The functions and engineering applications of the AMMs are also discussed. Finally, existing issues and future perspectives in this field are briefly described. This review is expected to provide the basis and inspiration for the follow-up research on AMMs.

15.
Adv Mater ; : e2107103, 2021 Oct 11.
Artigo em Inglês | MEDLINE | ID: mdl-34636109

RESUMO

Most previous efforts are devoted to developing transition metals as electrocatalysts guided by the d-band center model. The metals of the s-block of the periodic table have so far received little attention in the application of oxygen reduction reactions (ORR). Herein, a carbon catalyst with calcium (Ca) single atom coordinated with N and O is reported, which displays exceptional ORR activities in both acidic condition (E1/2  = 0.77 V, 0.1 m HClO4 ) and alkaline condition (E1/2  = 0.90 V, 0.1 m KOH). The CaN, O/C exhibits remarkable performance in zinc-air battery with a maximum power density of 218 mW cm-2 , superior to a series of catalysts reported so far. X-ray absorption near-edge structure (XANES) characterization confirms the formation of N- and O-atom-coordinated Ca in the carbon matrix. Density functional theory (DFT) calculations reveal that the high catalytic activity of main-group Ca is ascribed to the fact that its p-orbital electron structure is regulated by N and O coordination so that the highest peak (EP ) of the projected density of states (PDOS) for the Ca atom is moved close to the Fermi level, thereby facilitating the adsorption of ORR intermediates and electron transfer.

16.
Nucleic Acids Res ; 2021 Oct 20.
Artigo em Inglês | MEDLINE | ID: mdl-34669962

RESUMO

As an important post-translational modification, ubiquitination mediates ∼80% of protein degradation in eukaryotes. The degree of protein ubiquitination is tightly determined by the delicate balance between specific ubiquitin ligase (E3)-mediated ubiquitination and deubiquitinase-mediated deubiquitination. In 2017, we developed UbiBrowser 1.0, which is an integrated database for predicted human proteome-wide E3-substrate interactions. Here, to meet the urgent requirement of proteome-wide E3/deubiquitinase-substrate interactions (ESIs/DSIs) in multiple organisms, we updated UbiBrowser to version 2.0 (http://ubibrowser.ncpsb.org.cn). Using an improved protocol, we collected 4068/967 known ESIs/DSIs by manual curation, and we predicted about 2.2 million highly confident ESIs/DSIs in 39 organisms, with >210-fold increase in total data volume. In addition, we made several new features in the updated version: (i) it allows exploring proteins' upstream E3 ligases and deubiquitinases simultaneously; (ii) it has significantly increased species coverage; (iii) it presents a uniform confidence scoring system to rank predicted ESIs/DSIs. To facilitate the usage of UbiBrowser 2.0, we also redesigned the web interface for exploring these known and predicted ESIs/DSIs, and added functions of 'Browse', 'Download' and 'Application Programming Interface'. We believe that UbiBrowser 2.0, as a discovery tool, will contribute to the study of protein ubiquitination and the development of drug targets for complex diseases.

17.
Parasit Vectors ; 14(1): 537, 2021 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-34649597

RESUMO

BACKGROUND: Necator americanus is one of the major etiological agents of human ancylostomiasis. Historically, the epidemiology of ancylostomiasis in Henan Province of central China and the molecular characteristics of N. americanus have been poorly understood. METHODS: In this study, we report a case of ancylostomiasis in Zhengzhou city of Henan Province. We also review the epidemiology of ancylostomiasis in Henan Province from 1949 to 2020. In addition, the complete mitochondrial (mt) genome of one clinical isolate is fully characterized using Illumina sequencing. All available mt genomes of hookworms in GenBank were included to reconstruct the phylogeny using both maximum likelihood (ML) and Bayesian inference (BI) methods. RESULTS: A total of three worms were collected from the patient. These worms were identified as N. americanus based on morphological characteristics as well as confirmed by genotyping with the barcoding gene cox1. Although ancylostomiasis cases have dropped substantially in recent years, hookworm infection is still a public health problem in underdeveloped areas and remote rural areas in Henan Province. The mt genome features of the N. americanus contained 12 protein-coding genes (PCGs), 22 transfer RNA genes, two ribosomal RNA genes, and a major non-coding region. The nad1 gene showed high sequence variability among isolates, which is worth considering for future genetic studies of N. americanus. Phylogenetic analyses support the monophyly of hookworm isolates from different hosts and distinct geographical locations. CONCLUSIONS: The mt genome of N. americanus presented here will serve as a useful data set for studying population genetics and phylogenetic relationships of hookworms. Positive measures for preventing and controlling ancylostomiasis are required by both health services and individuals in Henan Province.

18.
J Hazard Mater ; 424(Pt A): 127330, 2021 Sep 23.
Artigo em Inglês | MEDLINE | ID: mdl-34600379

RESUMO

Plastic waste and its environmental hazards have been attracting public attention as a global sustainability issue. This study builds a neural network model to forecast plastic waste generation of the EU-27 in 2030 and evaluates how the interventions could mitigate the adverse impact of plastic waste on the environment. The black-box model is interpreted using SHapley Additive exPlanations (SHAP) for managerial insights. The dependence on predictors (i.e., energy consumption, circular material use rate, economic complexity index, population, and real gross domestic product) and their interactions are discussed. The projected plastic waste generation of the EU-27 is estimated to reach 17 Mt/y in 2030. With an EU targeted recycling rate (55%) in 2030, the environmental impacts would still be higher than in 2018, especially global warming potential and plastic marine pollution. This result highlights the importance of plastic waste reduction, especially for the clustering algorithm-based grouped countries with a high amount of untreated plastic waste per capita. Compared to the other assessed scenarios, Scenario 4 with waste reduction (50% recycling, 47.6% energy recovery, 2.4% landfill) shows the lowest impact in acidification, eutrophication, marine aquatic toxicity, plastic marine pollution, and abiotic depletion. However, the global warming potential (8.78 Gt CO2eq) is higher than that in 2018, while Scenario 3 (55% recycling, 42.6% energy recovery, 2.4% landfill) is better in this aspect than Scenario 4. This comprehensive analysis provides pertinent insights into policy interventions towards environmental hazard mitigation.

19.
Materials (Basel) ; 14(19)2021 Oct 08.
Artigo em Inglês | MEDLINE | ID: mdl-34640304

RESUMO

The degradation mechanisms for environmental barrier coatings (EBCs) under high-temperature water vapour conditions are vital for the service of aero-engine blades. This study proposes a theoretical model of high-temperature water vapour corrosion coupled with deformation, mass diffusion and chemical reaction based on the continuum thermodynamics and the actual water vapour corrosion mechanisms of an EBC system. The theoretical model is suitable for solving the stress and strain fields, water vapour concentration distribution and coating corrosion degree of an EBC system during the water vapour corrosion process. The results show that the thickness of the corrosion zone on the top of the EBC system depended on water vapour diffusion, which had the greatest influence on the corrosion process. The top corroded area of the rare-earth silicate EBC system was significantly evident, and there was a clear dividing line between the un-corroded and corroded regions.

20.
Chemosphere ; : 132701, 2021 Oct 26.
Artigo em Inglês | MEDLINE | ID: mdl-34715100

RESUMO

The exploration of low-cost, long-term stable, and highly electrochemically active cathode catalysts is important for the practical application of microbial fuel cell (MFC). In this work, a series of the 3D hierarchical porous Co-N-C (3DHP Co-N-C) materials are designed and synthesized by a metal-organic framework ZIF-67 as a precursor and SiO2 sphere of different sizes as the hard template. The 3DHP Co-N-C-2 with 129 nm macropore exhibits excellent ORR performance in 0.1 M KOH solution with a half-wave potential of 0.80 V vs. RHE and superior durability than Pt/C (20%) due to the specific macropore-mesopore-micropore structure that exposes a large number of active sites and accelerates the electrolyte transport and oxygen diffusion. The MFC with 3DHP Co-N-C-2 as the cathode catalysts shows excellent performance with a maximum power density of 426.9±7.87 mW m-2 and favorable durability after 50 d of operation. In addition, 16s rDNA results reveal the presence of different dominant electrogenic bacteria and different abundance of important non-electrogenic bacteria in the anode biofilm in MFCs using cathode catalysts with different ORR activity. And 3DHP Co-N-C-2 was found to be beneficial to the synergistic effect of electrogenic and non-electrogenic bacteria. This study explores electrocatalysts in terms of both electrocatalytic activity and anode microorganisms, providing new and comprehensive insights into the power generation of MFC.

SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...