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1.
ACS Omega ; 6(37): 23643-23653, 2021 Sep 21.
Artigo em Inglês | MEDLINE | ID: mdl-34568644

RESUMO

In this paper, the brief development of chemical kinetic modeling of natural gas is discussed, with emphasis on the development of chemical kinetic mechanisms describing fuel oxidation. The addition of ethane and/or propane to natural gas not only decreases the ignition delay times but also increases flame speeds. Thus, the mixture of methane, ethane, and propane rather than bare methane obtains more accurate predictions for the combustion and emission characteristics of natural gas. This paper also evaluates different comprehensive mechanisms employed for natural gas engines and pointed out their advantages and disadvantages, giving guidance for the selection of mechanisms during the development of natural gas engines.

2.
Nanoscale ; 13(31): 13174-13194, 2021 Aug 21.
Artigo em Inglês | MEDLINE | ID: mdl-34477725

RESUMO

2D heterostructures have very recently witnessed a boom in scientific and technological activities owing to the customized spatial orientation and tailored physical properties. A large amount of 2D heterostructures have been constructed on the basis of the combination of mechanical exfoliation and located transfer method, opening wide possibilities for designing novel hybrid systems with tuned structures, properties, and applications. Among the as-developed 2D heterostructures, in-plane graphene and h-BN heterostructures have drawn the most attention in the past few decades. The controllable synthesis, the investigation of properties, and the expansion of applications have been widely explored. Herein, the fabrication of graphene and h-BN heterostructures is mainly focused on. Then, the spatial configurations for the heterostructures are systematically probed to identify the highly related unique features. Moreover, as a most promising approach for the scaled production of 2D materials, the in situ CVD fabrication of the heterostructures is summarized, demonstrating a significant potential in the controllability of size, morphology, and quality. Further, the recent applications of the 2D heterostructures are discussed. Finally, the concerns and challenges are fully elucidated and a bright future has been envisioned.

3.
J Environ Manage ; 297: 113419, 2021 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-34378543

RESUMO

Since climate change mitigation is the central debate of modern literature, the realization of carbon neutrality in response to diversified macroeconomic variables is the most crucial concern of international economies. However, the critical role of trade and renewable electricity output in export diversification-environmental nexus is missing. Therefore, this study investigates the combined influence of trade openness, exports diversification, and renewable electricity output on carbon dioxide emissions (CO2) in China from 1989 through 2019. Applying novel time series econometric techniques robust to structural breaks, following new outcomes are obtained. Firstly, long-run equilibrium cointegration existed among the under-analysis variables. Secondly, export diversification and renewable electricity output are predicted to decelerate CO2, supporting carbon neutrality in the long run. Thirdly, trade openness and gross domestic product accelerated the CO2, delaying carbon neutrality accomplishment. Most importantly, significant structural break dummy interacting with trade openness implicated that during the post-2001 era, China's trade openness extensively deteriorated the environmental quality in the face of trade liberalization obtained after joining the World Trade Organization (WTO). Based on empirical results, export diversification and renewable electricity production policies should be mutually non-exclusive and closely coordinated. Further, to counter the carbon emission acceleration impact of trade openness, increasing the share of green tradable products is suggested. Finally, bilateral trade restructuring is recommended to realize the long-term dream of economic sustainability and carbon neutrality.


Assuntos
Dióxido de Carbono , Desenvolvimento Econômico , Dióxido de Carbono/análise , China , Eletricidade , Produto Interno Bruto , Energia Renovável
4.
J Hazard Mater ; 422: 126844, 2021 Aug 05.
Artigo em Inglês | MEDLINE | ID: mdl-34399210

RESUMO

The transmission of airborne antibiotic resistance genes (ARGs) loaded on particle is a significant global public health concern. Up to date, the dispersal pattern of airborne ARGs remains unclear despite their critical role in multiregional transmission. In this study, airborne ARGs loaded on fine particulate matter (PM2.5) and source tracking based on the airflow trajectories were performed by the potential source contribution function (PSCF) and concentration weighted trajectory (CWT) model. The results show that the absolute abundance of ARG subtypes were generally twice times higher in the winter season than that in the summer season, which could be attributable to winter haze events with high particulate matter concentrations in Handan. Exogenous input from serious haze events and local release of ARGs loaded on PM2.5 of air masses may cause higher levels of ARGs in the winter. Moreover, based on the positive correlation between the abundance of ARGs and PM2.5 concentration, a source tracing model of airborne ARGs was proposed to the estimate of ARGs release and dissemination. This study highlights airborne ARGs transmission loaded on PM2.5 of air masses, which facilitating the global spread of antibiotic resistance.

5.
Front Microbiol ; 12: 694361, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34367093

RESUMO

Listeria innocua are Gram-positive rod-shaped bacteria, which are not generally infectious as opposed to Listeria monocytogenes. However, the comparatively high genomic similarity between both along with on occasion, their coexistence in similar ecological niches may present the opportunity for resistance or virulence gene transfer. In this study, three multi-drug resistant L. innocua originally cultured from food were put forward for long-read genome sequencing. Chromosome and plasmid genomes were assembled and annotated. Analysis demonstrated that the resistant phenotypes correlated well with genotypes. Three plasmids pLI42, pLI203, and pLI47-1 were identified which harbor resistance islands. Sequence alignments suggested that plasmids pLI42 and pLI203 were highly similar to a previously sequenced L. monocytogenes plasmid pLR1. Similarly, another three types of resistance gene islands were observed on chromosome, including tet(M) gene islands (transposon Tn916 orthologs), dfrG gene islands and optrA-erm(A) gene islands. All three L. innocua isolates possessed listeria pathogenicity island-4 (LIPI-4) which is linked to cases of mengitis. Further genome environment and phylogenic analysis of regions flanking LIPI-4 of L. innocua and L. monocytogenes showed that these may have common origins and with the potential to transmit from the former. Our findings raise the possible need to include both L. monocytogenes and L. innocua in food surveillance programs so as to further understand of the origins of antimicrobial resistance and virulence markers of public health importance in L. monocytogenes.

6.
Front Microbiol ; 12: 686189, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34354686

RESUMO

Cronobacter is a foodborne pathogen associated with severe infections and high mortality in neonates. The bacterium may also cause gastroenteritis, septicemia, and urinary tract and wound infectious in adults. A total of 15 Cronobacter isolates collected from 617 raw materials and environment samples from Powdered Infant Formula manufacturing factories during 2016 in Shaanxi, China, were analyzed for antimicrobial susceptibilities, species identification, biofilm formation, and whole-genome sequencing. The results showed that all 15 isolates were Cronobacter sakazakii, while the antimicrobial susceptibility test showed that all 15 C. sakazakii were pan susceptible. Most isolates were able to produce a weak biofilm, and two isolates from soil samples produced a strong biofilm formation. All isolates were classified into seven STs including ST4, ST40, ST64, ST93, ST148, ST256, and ST494, with ST64 (4/15, 26.7%) being dominant, and most were clinically related. The isolates harbored at least 11 virulence genes and two plasmids, with one isolate being positive for all virulence genes. Phylogenetic and ANI analysis showed strong clustering by sequence types and isolates from different sources or regions with a similar genomic background. The fact that isolates were obtained from raw materials and environment samples of PIF facilities shared a close phylogeny with one another suggests that cross-contamination events may have occurred between the processing room and external environments, which may give rise to a recurring risk of a continuous contamination during production.

7.
Acupunct Med ; : 9645284211033607, 2021 Jul 28.
Artigo em Inglês | MEDLINE | ID: mdl-34318713
8.
Artigo em Inglês | MEDLINE | ID: mdl-34332120

RESUMO

MicroRNAs (miRNAs) are important regulators of gene expression. The large-scale detection and profiling of miRNAs have accelerated with the development of high-throughput small RNA sequencing (sRNA-Seq) techniques and bioinformatics tools. However, generating high-quality comprehensive miRNA annotations remains challenging due to the intrinsic complexity of sRNA-Seq data and inherent limitations of existing miRNA predictions. Here, we present iwa-miRNA, a Galaxy-based framework that can facilitate miRNA annotation in plant species by combining computational analysis and manual curation. iwa-miRNA is specifically designed to generate a comprehensive list of miRNA candidates, bridging the gap between already annotated miRNAs provided by public miRNA databases and new predictions from sRNA-Seq datasets. It can also assist users in selecting promising miRNA candidates in an interactive mode, contributing to the accessibility and reproducibility of genome-wide miRNA annotation. iwa-miRNA is user-friendly and can be easily deployed as a web application for researchers without programming experience. With flexible, interactive, and easy-to-use features, iwa-miRNA is a valuable tool for the annotation of miRNAs in plant species with reference genomes. We illustrated the application of iwa-miRNA for miRNA annotation using data from plant species with varying genomic complexity. The source codes and web server of iwa-miRNA are freely accessible at: http://iwa-miRNA.omicstudio.cloud/.

9.
mSystems ; 6(3): e0118520, 2021 Jun 29.
Artigo em Inglês | MEDLINE | ID: mdl-34100643

RESUMO

Staphylococcus aureus is a worldwide leading cause of numerous diseases ranging from food-poisoning to lethal infections. Methicillin-resistant S. aureus (MRSA) has been found capable of acquiring resistance to most antimicrobials. MRSA is ubiquitous and diverse even in terms of antimicrobial resistance (AMR) profiles, posing a challenge for treatment. Here, we present a comprehensive study of S. aureus in China, addressing epidemiology, phylogenetic reconstruction, genomic characterization, and identification of AMR profiles. The study analyzes 673 S. aureus isolates from food as well as from hospitalized and healthy individuals. The isolates have been collected over a 9-year period, between 2010 and 2018, from 27 provinces across China. By whole-genome sequencing, Bayesian divergence analysis, and supervised machine learning, we reconstructed the phylogeny of the isolates and compared them to references from other countries. We identified 72 sequence types (STs), of which, 29 were novel. We found 81 MRSA lineages by multilocus sequence type (MLST), spa, staphylococcal cassette chromosome mec element (SCCmec), and Panton-Valentine leukocidin (PVL) typing. In addition, novel variants of SCCmec type IV hosting extra metal and antimicrobial resistance genes, as well as a new SCCmec type, were found. New Bayesian dating of the split times of major clades showed that ST9, ST59, and ST239 in China and European countries fell in different branches, whereas this pattern was not observed for the ST398 clone. On the contrary, the clonal transmission of ST398 was more intermixed in regard to geographic origin. Finally, we identified genetic determinants of resistance to 10 antimicrobials, discriminating drug-resistant bacteria from susceptible strains in the cohort. Our results reveal the emergence of Chinese MRSA lineages enriched of AMR determinants that share similar genetic traits of antimicrobial resistance across human and food, hinting at a complex scenario of evolving transmission routes. IMPORTANCE Little information is available on the epidemiology and characterization of Staphylococcus aureus in China. The role of food is a cause of major concern: staphylococcal foodborne diseases affect thousands every year, and the presence of resistant Staphylococcus strains on raw retail meat products is well documented. We studied a large heterogeneous data set of S. aureus isolates from many provinces of China, isolated from food as well as from individuals. Our large whole-genome collection represents a unique catalogue that can be easily meta-analyzed and integrated with further studies and adds to the library of S. aureus sequences in the public domain in a currently underrepresented geographical region. The new Bayesian dating of the split times of major drug-resistant enriched clones is relevant in showing that Chinese and European methicillin-resistant S. aureus (MRSA) have evolved differently. Our machine learning approach, across a large number of antibiotics, shows novel determinants underlying resistance and reveals frequent resistant traits in specific clonal complexes, highlighting the importance of particular clonal complexes in China. Our findings substantially expand what is known of the evolution and genetic determinants of resistance in food-associated S. aureus in China and add crucial information for whole-genome sequencing (WGS)-based surveillance of S. aureus.

10.
Front Microbiol ; 12: 628538, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-34079526

RESUMO

The environmental bacterium Burkholderia gladioli pv. cocovenenans (B. cocovenenans) has been linked to fatal food poisoning cases in Asia and Africa. Bongkrekic acid (BA), a mitochondrial toxin produced by B. cocovenenans, is thought to be responsible for these outbreaks. While there are over 80 species in the Burkholderia genus, B. cocovenenans is the only pathovar capable of producing BA and causing human death. However, the genomic features of B. gladioli and the evolution of the BA biosynthesis gene cluster, bon, in B. cocovenenans remain elusive. In this study, 239 whole genome sequences (WGSs) of B. gladioli, isolated from 12 countries collected over 100 years, were used to analyze the intra-species genomic diversity and phylogenetic relationships of B. gladioli and to explore the origin and evolution of the bon gene cluster. Our results showed that the genome-wide average nucleotide identity (ANI) values were above 97.29% for pairs of B. gladioli genomes. Thirty-six of the 239 (15.06%) B. gladioli genomes, isolated from corn, rice, fruits, soil, and patients from Asia, Europe, North America, and South America, contained the bon gene cluster and formed three clades within the phylogenetic tree. Pan- and core-genome analysis suggested that the BA biosynthesis genes were recently acquired. Comparative genome analysis of the bon gene cluster showed that complex recombination events contributed to this toxin biosynthesis gene cluster's evolution and formation. This study suggests that a better understanding of the genomic diversity and evolution of this lethal foodborne pathovar will potentially contribute to B. cocovenenans food poisoning outbreak prevention.

11.
Front Med (Lausanne) ; 8: 657566, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33996860

RESUMO

Purpose: To construct quantifiable models of imaging features by machine learning describing early changes of optic disc and peripapillary region, and to explore their performance as early indicators for choroidal thickness (ChT) in young myopic patients. Methods: Eight hundred and ninety six subjects were enrolled. Imaging features were extracted from fundus photographs. Macular ChT (mChT) and peripapillary ChT (pChT) were measured on swept-source optical coherence tomography scans. All participants were divided randomly into training (70%) and test (30%) sets. Imaging features correlated with ChT were selected by LASSO regression and combined into new indicators of optic disc (IODs) for mChT (IOD_mChT) and for pChT (IOD_pChT) by multivariate regression models in the training set. The performance of IODs was evaluated in the test set. Results: A significant correlation between IOD_mChT and mChT (r = 0.650, R 2 = 0.423, P < 0.001) was found in the test set. IOD_mChT was negatively associated with axial length (AL) (r = -0.562, P < 0.001) and peripapillary atrophy (PPA) area (r = -0.738, P < 0.001) and positively associated with ovality index (r = 0.503, P < 0.001) and torsion angle (r = 0.242, P < 0.001) in the test set. Every 1 × 10 µm decrease in IOD_mChT was associated with an 8.87 µm decrease in mChT. A significant correlation between IOD_pChT and pChT (r = 0.576, R 2 = 0.331, P < 0.001) was found in the test set. IOD_pChT was negatively associated with AL (r = -0.478, P < 0.001) and PPA area (r = -0.651, P < 0.001) and positively associated with ovality index (r = 0.285, P < 0.001) and torsion angle (r = 0.180, P < 0.001) in the test set. Every 1 × 10 µm decrease in IOD_pChT was associated with a 9.64 µm decrease in pChT. Conclusions: The study introduced a machine learning approach to acquire imaging information of early changes of optic disc and peripapillary region and constructed quantitative models significantly correlated with choroidal thickness. The objective models from fundus photographs represented a new approach that offset limitations of human annotation and could be applied in other areas of fundus diseases.

12.
Nat Commun ; 12(1): 2024, 2021 04 01.
Artigo em Inglês | MEDLINE | ID: mdl-33795666

RESUMO

The end-Permian mass extinction (EPME) was the most severe extinction event in the past 540 million years, and the Siberian Traps large igneous province (STLIP) is widely hypothesized to have been the primary trigger for the environmental catastrophe. The killing mechanisms depend critically on the nature of volatiles ejected during STLIP eruptions, initiating about 300 kyr before the extinction event, because the atmosphere is the primary interface between magmatism and extinction. Here we report Ni isotopes for Permian-Triassic sedimentary rocks from Arctic Canada. The δ60Ni data range from -1.09‰ to 0.35‰, and exhibit the lightest δ60Ni compositions ever reported for sedimentary rocks. Our results provide strong evidence for global dispersion and loading of Ni-rich aerosol particles into the Panthalassic Ocean. Our data demonstrate that environmental degradation had begun well before the extinction event and provide a link between global dispersion of Ni-rich aerosols, ocean chemistry changes, and the EPME.

13.
ACS Omega ; 6(8): 5921-5932, 2021 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-33681630

RESUMO

Currently, selective catalytic reduction (SCR) systems have become an essential part in diesel engines, and urea crystallization is one of the most serious issues in SCR systems. In this paper, the urea deposit formation processes in the SCR system were investigated by numerical simulations based on a fluid-solid coupling method. The results show that the masses of the wall film and solid urea are larger at conditions with lower temperatures and higher injection rates. At higher temperatures, cyanate ions and ammonium ions are the most predominant compositions in the wall film, while at lower temperatures, solid urea is the main composition. It could also be deduced that the location of urea crystallization is more affected by the design of mixer at higher temperatures, whereas at lower temperatures, the location and installation angle of urea-water solution injector play a more important role.

14.
Sci Rep ; 11(1): 4887, 2021 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-33649457

RESUMO

Water level conditions are the key factors that affect the growth and distribution of wetland plants. Using Carex cinerascens (C. cinerascens) as the study species, we employ indoor simulations and field surveys. Our results show that C. cinerascens can adapt to rhythmic changes in the water level through different adaptation strategies. Compared to that of the control group, plant growth was better with a 0-0.4 cm/d water level rate, and plant growth was in the 42-56 cm range to that a 1.0-1.4 cm/d water level rate. Furthermore, it was observed that 0-0.4 cm/d was the most suitable growth rate, with 0.6-1.0 cm/d and 0-32 cm being the ideal plant tolerance ranges, and increasing to 1.0-1.4 cm/d and 32-56 cm exceeds the plant tolerance threshold. In the middle and late period of the experiment (25-45 d), the ecological characteristics of the plants changed significantly. For example, the root-to-shoot ratio of the plant in the stable water level reached 26.1. In our field observations, plant biomass can be influenced by a variety of environmental factors. The frequency of the species was the largest at an elevation of 15 m, and the growth status of the dominant and companion species of C. cinerascens was weakened with an increase in soil moisture content. The suitable water content for C. cinerascens growth was 27.6-57.3%, the distribution elevation was 12.54-16.59 m, and the optimum elevation was 13.56-15.54 m. The study is expected to provide a reference for wetland ecology research and wetland protection and restoration, a theoretical reference for the coordination of water resource development and utilization of Poyang Lake and ecological protection of important lakes and wetlands, and an important scientific basis for wetland hydrologic regulation, ecological restoration and biodiversity conservation.

15.
J Environ Sci (China) ; 103: 157-171, 2021 May.
Artigo em Inglês | MEDLINE | ID: mdl-33743898

RESUMO

Selective catalytic reduction is the most efficient and reliable equipment for NOx control in current diesel engines. However, the issue of urea crystallization becomes increasingly serious with the implement of the new emissions standards. In this paper, urea deposit samples collected from engine test bed and tube furnace were characterized by thermogravimetric analysis and Fourier transform-infrared analysis to aid the comprehension of urea deposit formation. Moreover, thermogravimetric tests were conducted to disclose the effects of catalyst on the thermal decomposition processes of urea deposit. The results indicated that less temperature resistant species are formed in the engine test bed than in the tube furnace at conditions with the same temperatures. The main compositions in the World Harmonized Transient Cycle (WHTC) urea deposits are urea, cyanuric acid (CYA) and ammelide, implying that accelerating the decomposition of these species could prevent the accumulation of urea deposit. CuWTi, Cuß and CuZSM catalysts could lead to increased yield of CYA during pure urea thermolysis. Cuß, CuWTi and VWTi catalysts tend to promote the thermolysis of CYA while VWTi has the most significant catalytic effects on the thermal decomposition of ammelide and ammeline.


Assuntos
Poluentes Atmosféricos , Emissões de Veículos , Poluentes Atmosféricos/análise , Catálise , Gasolina , Ureia , Emissões de Veículos/análise
16.
Sci Total Environ ; 772: 145475, 2021 Jun 10.
Artigo em Inglês | MEDLINE | ID: mdl-33770885

RESUMO

Electronic cigarettes (E-cigarette) are an alternative for traditional cigarette smokers to quit smoking. Based on the current understanding, electronic cigarettes have rapidly become popular among existing smokers and former non-smokers. However, increasing research at different levels reveals that e-cigarettes are unsafe. This review provides an overview of the toxicology of e-cigarettes based on existing in vivo and in vitro studies and compares their toxicity with that of traditional cigarettes. Moreover, we describe the associated toxicity components in e-cigarettes, as well as the potential mechanism by which e-cigarettes exert toxic effects. As is known to all, the nicotine in traditional cigarettes and e-cigarettes has certain toxicity. Besides, a few studies have shown that propylene glycol and vegetable glycerin mixture and flavoring agents in e-cigarettes also are the key components causing adverse effects in animals or cells. There is insufficient scientific evidence on the toxicity of e-cigarettes due to the lack of standardized research methods, prompting the need to conduct a comprehensive toxicity assessment of e-cigarette toxicity to elucidate the safety issues of e-cigarettes. Eventually, a basis for decision-making on whether people use e-cigarettes will be obtained.


Assuntos
Sistemas Eletrônicos de Liberação de Nicotina , Produtos do Tabaco , Animais , Glicerol , Nicotina/toxicidade , Fumar
17.
Zhongguo Zhen Jiu ; 41(1): 9-12, 2021 Jan 12.
Artigo em Chinês | MEDLINE | ID: mdl-33559434

RESUMO

OBJECTIVE: To compare the therapeutic effect on sensory impairment in the recovery stage of cerebral infarction between the combined treatment of acupotomy and Xingnao Kaiqiao acupuncture therapy (for regaining consciousness and opening the orifices) and the simple application of Xingnao Kaiqiao acupuncture therapy. METHODS: A total of 80 patients with cerebral infarction in the recovery stage were randomized into an observation group (40 cases, 2 cases dropped off) and a control group (40 cases, 1 case dropped off). On the basis of the conventional treatment of internal medicine, in the control group, Xingnao Kaiqiao acupuncture therapy was adopted at Shuigou (GV 26), Neiguan (PC 6), Sanyinjiao (SP 6), etc., once daily, 6 times a week. In the observation group, on the base of the treatment as the control group, acupotomy was used at extraoccipital protuberance, posterior atlas nodules, cervical facet ligaments and posterior transverse nodules, once a week. The total treatment duration was 4 weeks. The scores of Fugl-Meyer assessment scale (FMA) and the visual analogue scale (VAS) were observed before and after treatment in the patients of the two groups. The clinical therapeutic effect was evaluated in the two groups. RESULTS: After treatment, FMA scores were increased and VAS scores were decreased in the patients of the two groups (P<0.05). The increase range of FMA score and the decrease range of VAS score in the observation group were larger than those in the control group (P<0.05). The total effective rate was 89.5% (34/38) in the observation group, higher than 76.9% (30/39) in the control group (P<0.05). CONCLUSION: The combined treatment of acupotomy and Xingnao Kaiqiao acupuncture therapy relieves sensory impairment and pain symptoms in the patients with cerebral infarction in the recovery stage and its therapeutic effect is better than the simple use of Xingnao Kaiqiao acupuncture therapy.


Assuntos
Terapia por Acupuntura , Acidente Vascular Cerebral , Pontos de Acupuntura , Infarto Cerebral/terapia , Estado de Consciência , Humanos , Resultado do Tratamento
18.
Chem Commun (Camb) ; 57(8): 994-997, 2021 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-33399596

RESUMO

Hydroxyapatite nanoparticles (HAP NPs) are blended with TiO2 NPs to prepare mixed mesoporous scaffolds which are used to prepare high efficiency perovskite solar cells (PSCs) with a best power conversion efficiency (PCE) of 20.98%. HAP not only increases the PCE but also limits the concentration of Pb released in water from intentionally broken PSCs by ion sequestration thereby potentially offering a promising in-device fail-safe system.


Assuntos
Compostos de Cálcio/química , Fontes de Energia Elétrica , Chumbo/química , Óxidos/química , Energia Solar , Titânio/química , Durapatita , Microscopia Eletrônica de Varredura , Estrutura Molecular , Nanopartículas
19.
IEEE Trans Image Process ; 30: 2461-2475, 2021.
Artigo em Inglês | MEDLINE | ID: mdl-33481712

RESUMO

The goal of exemplar-based texture synthesis is to generate texture images that are visually similar to a given exemplar. Recently, promising results have been reported by methods relying on convolutional neural networks (ConvNets) pretrained on large-scale image datasets. However, these methods have difficulties in synthesizing image textures with non-local structures and extending to dynamic or sound textures. In this article, we present a conditional generative ConvNet (cgCNN) model which combines deep statistics and the probabilistic framework of generative ConvNet (gCNN) model. Given a texture exemplar, cgCNN defines a conditional distribution using deep statistics of a ConvNet, and synthesizes new textures by sampling from the conditional distribution. In contrast to previous deep texture models, the proposed cgCNN does not rely on pre-trained ConvNets but learns the weights of ConvNets for each input exemplar instead. As a result, cgCNN can synthesize high quality dynamic, sound and image textures in a unified manner. We also explore the theoretical connections between our model and other texture models. Further investigations show that the cgCNN model can be easily generalized to texture expansion and inpainting. Extensive experiments demonstrate that our model can achieve better or at least comparable results than the state-of-the-art methods.

20.
J Med Internet Res ; 22(12): e19470, 2020 12 02.
Artigo em Inglês | MEDLINE | ID: mdl-33151892

RESUMO

BACKGROUND: In recent years, public health incidents that pose a serious threat to public life have occurred frequently in China. The use of social media by public health authorities has helped to reduce these threats by increasing effective risk communication between the government and the public. OBJECTIVE: The aim of this study is to reveal how China's Center for Disease Control and Prevention (CDC) uses social media to improve three aspects of health communication between the government and the public: adoption, operation, and interaction. METHODS: To analyze the 134 CDC government Weibo accounts at the provincial- and prefecture-level administration regions in mainland China, we collected their account data and extracted 1215 Weibo tweets. We also supplemented the data to reveal the overall performance of the CDC's government Weibo use during the COVID-19 crisis. RESULTS: The registration rate of the CDC's government Weibo accounts increased year by year, and the local authorities registered Weibo accounts before the central government authorities. In total, 29.8% (n=134) of the 450 CDC facilities have registered an account. Among the 134 CDC facilities that have registered Weibo accounts, the registration rate in the eastern region (n=68, 50.7%) was higher than those in the central region (n=30, 22.4%) and the western region (n=36, 26.9%). Nearly 90.0% of these Weibo accounts had official certification, but there were dropouts in the specific operating process. One-third of the accounts have not been updated for more than 1 year, and the number of Weibo followers was polarized, with a maximum and minimum difference of 1 million. The response rate to users' comments was less than 1%. Emergency information, multimedia content, and original content were more helpful in promoting communication between the government and the public. Such interaction was partially improved during the COVID-19 pandemic. The CDC updated the daily epidemic situation and provided popular science information for epidemic prevention and control for the public in a timely manner. CONCLUSIONS: China's CDC is using more social media to popularize daily health information and has taken the first step to improve communication between the government and the public. However, equal dialogue, two-way interactions, and effective communication with the public still need improvement.


Assuntos
COVID-19/epidemiologia , Órgãos Governamentais , Comunicação em Saúde/métodos , Saúde Pública/métodos , Mídias Sociais/estatística & dados numéricos , Inquéritos e Questionários , China/epidemiologia , Humanos , Pandemias , SARS-CoV-2
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