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1.
Proc Natl Acad Sci U S A ; 120(41): e2305692120, 2023 10 10.
Artigo em Inglês | MEDLINE | ID: mdl-37782791

RESUMO

Governments worldwide have announced stimulus packages to remobilize the labor force after COVID-19 and therefore to cope with the COVID-19-related recession. However, it is still unclear how to facilitate large-scale work resumption. This paper aims to clarify the issue by analyzing the large-scale prefecture-level dataset of human mobility trajectory information for 320 million workers and about 500,000 policy documents in China. We model work resumption as a collective behavioral change due to configurations of capacity, motivation, and policy instruments by using qualitative comparative analysis. We find that the effectiveness of post-COVID-19 recovery stimulus varied across China depending on the fiscal and administrative capacity and the policy motivation of the prefecture. Subnational fiscal and procurement policies were more effective for the wholesale and retail sector and the hotel and catering sector, whereas the manufacturing and business services sectors required more effort regarding employment policies. Due to limited prefectural capacity and wavering policy motivation, the simultaneous adoption of fiscal, employment, and procurement policy interventions endangered post-COVID-19 work resumption. We highlight the necessity of tailored postcrisis recovery strategies based on local fiscal and administrative capacity and the sectoral structure.


Assuntos
COVID-19 , Humanos , COVID-19/epidemiologia , China/epidemiologia , Política Pública , Emprego
2.
Ecotoxicol Environ Saf ; 272: 116056, 2024 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-38301579

RESUMO

Using Caenorhabditis elegans as animal model, we investigated the effect of exposure to polystyrene nanoparticles (PS-NPs) in the range of µg/L on high glucose toxicity induction. With lifespan and locomotion behavior as endpoints, we observed that PS-NP (10 and 100 µg/L) enhanced toxicity in 50 mM glucose treated animals. In insulin signaling pathway, expressions of genes encoding insulin receptor (daf-2), kinases (age-1 and akt-1/2), and insulin peptides (ins-9, ins-6, and daf-28) were increased, and expressions of daf-16 and its target of sod-3 were decreased in high glucose treated nematodes followed by PS-NP exposure. Toxicity enhancement in high glucose treated nematodes by PS-NP exposure was inhibited by RNAi of daf-2, age-1, akt-2, akt-1, and 3 insulin peptides genes, but increased by RNAi of daf-16 and sod-3. The resistance of animals with RNAi of daf-2 to toxicity in high glucose treated nematodes followed by PS-NP exposure could be suppressed by RNAi of daf-16. Moreover, in high glucose treated animals followed by PS-NP exposure, daf-2 expression was inhibited by RNAi of ins-6, ins-9, and daf-28. Our data demonstrated the risk of PS-NP exposure in enhancing the high glucose toxicity. More importantly, alteration in expression of genes in insulin signaling pathway was associated with the toxicity enhancement in high glucose treated nematodes followed by PS-NP exposure.


Assuntos
Proteínas de Caenorhabditis elegans , Nanopartículas , Animais , Caenorhabditis elegans , Insulina/metabolismo , Poliestirenos/toxicidade , Poliestirenos/metabolismo , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Proteínas Proto-Oncogênicas c-akt/metabolismo , Transdução de Sinais , Nanopartículas/toxicidade , Longevidade
3.
Analyst ; 148(6): 1214-1220, 2023 Mar 13.
Artigo em Inglês | MEDLINE | ID: mdl-36825426

RESUMO

Timely and accurate diagnosis of COVID-19 is critical for controlling the pandemic. As the standard method to diagnose SARS-CoV-2, the real-time reverse transcription polymerase chain reaction (RT-qPCR) has good convenience. However, RT-qPCR still has a relatively high false-negative rate, particularly in the case of detecting low viral loads. In this study, using selenium-modified nucleoside triphosphates (dNTPαSe) in the RT-PCR reactions, we successfully increased the detection sensitivity and reduced the false-negative rate in COVID-19 diagnosis. By detecting positive controls, pseudovirus, and clinical samples with the commercial kits, we found that the dNTPαSe supplementation to these kits could generally offer smaller Ct values, permit the viral detection even in single-digit copies, and increase the detection specificity, sensitivity, and accuracy, thereby reducing the false-negative rate. Our experimental results demonstrated that dNTPαSe supplementation can make the commercial kits more specific, sensitive, and accurate, and this method is a convenient and efficient strategy for the disease detection and diagnosis.


Assuntos
COVID-19 , Humanos , COVID-19/diagnóstico , SARS-CoV-2/genética , Teste para COVID-19 , Erros de Diagnóstico , Reação em Cadeia da Polimerase em Tempo Real/métodos , Sensibilidade e Especificidade , Suplementos Nutricionais , RNA Viral
4.
Small ; 18(7): e2103734, 2022 02.
Artigo em Inglês | MEDLINE | ID: mdl-34825473

RESUMO

Multiresponsive flexile sensors with strain, temperature, humidity, and other sensing abilities serving as real electronic skin (e-skin) have manifested great application potential in flexible electronics, artificial intelligence (AI), and Internet of Things (IoT). Although numerous flexible sensors with sole sensing function have already been reported since the concept of e-skin, that mimics the sensing features of human skin, was proposed about a decade ago, the ones with more sensing capacities as new emergences are urgently demanded. However, highly integrated and highly sensitive flexible sensors with multiresponsive functions are becoming a big thrust for the detection of human body motions, physiological signals (e.g., skin temperature, blood pressure, electrocardiograms (ECG), electromyograms (EMG), sweat, etc.) and environmental stimuli (e.g., light, magnetic field, volatile organic compounds (VOCs)), which are vital to real-time and all-round human health monitoring and management. Herein, this review summarizes the design, manufacturing, and application of multiresponsive flexible sensors and presents the future challenges of fabricating these sensors for the next-generation e-skin and wearable electronics.


Assuntos
Inteligência Artificial , Dispositivos Eletrônicos Vestíveis , Eletrônica , Humanos , Umidade , Suor
5.
Ecotoxicol Environ Saf ; 165: 299-306, 2018 Dec 15.
Artigo em Inglês | MEDLINE | ID: mdl-30205332

RESUMO

Water purification provides a feasible way to relieve the pressure of water shortage and water pollution which we are facing and adsorption is one of the most effective ways to turn polluted water into clean water. Here, we prepared graphene-tannic acid hydrogel using graphene oxide and tannic acid, a natural green reducer and adsorbent, through one-step hydrothermal method. The composition, structure, and morphology of the compounds were systematically examined. The adsorption of dyes was mainly influenced by the morphology and chemical properties of gel. The addition of tannic acid, a molecule rich in oxygen containing functional groups, changed the surface chemistry of graphene sheets and microstructures of gels, which was beneficial for contaminate adsorption. Compared with reduced graphene oxide hydrogel, the graphene-tannic acid hydrogel showed an outstanding adsorption capacity for organic dye methylene blue, more than 500 mg/g at pH 10 and the maximum adsorption capacity was up to 714 mg/g. After adsorption, ethanol and inorganic acid solution can be used as desorption agent and there was no significant adsorption capacity loss after 5 cycles.


Assuntos
Corantes/química , Grafite/química , Hidrogéis/química , Taninos/química , Poluentes Químicos da Água/química , Adsorção , Hidrogéis/síntese química , Cinética , Azul de Metileno/química , Poluição da Água , Purificação da Água/métodos
6.
Macromol Rapid Commun ; 38(23)2017 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-29083103

RESUMO

This article provides a novel and efficient method of "self-assembly/modification/dispersion" for the preparation of functionalized cellulose nanoparticles (CNPs) based on regenerated cellulose hydrogel (RCH). The process of the preparation of CNPs is simplified greatly, which contributes to broadening the utilization of CNPs. Under the given conditions, cellulose chains self-assemble into nanoparticles, which connect with each other to form strings and walls of nanoparticles inside RCH. Then, RCH acts as the hydrophilic precursor of the preparation of CNPs and is modified by oligo side chains to obtain functionalized RCH with imperfect cellulose II structures. After dispersing the functionalized RCH in dimethyl sulfoxide, individual CNPs are finally isolated from functionalized RCH as a result of the decline of the crystallinity of CNPs. Obtained CNPs possess uniform size and good thermal stability, and also exhibit excellent dispersibility in organic solvents. The particle size of CNPs can be adjusted easily by oligo content and particle size of the self-assembled cellulose nanoparticles in RCH. Prepared CNPs are promising candidates for polymer modification in terms of fillers, and for biomedical fields with respect to drug delivery.


Assuntos
Celulose/química , Hidrogel de Polietilenoglicol-Dimetacrilato/química , Nanopartículas/química , Portadores de Fármacos/química , Sistemas de Liberação de Medicamentos/métodos , Interações Hidrofóbicas e Hidrofílicas
7.
Phys Chem Chem Phys ; 19(20): 12712-12719, 2017 May 24.
Artigo em Inglês | MEDLINE | ID: mdl-28480937

RESUMO

Polypropylene (PP) and five kinds of monodisperse polystyrene (PS) with different terminal relaxation times were used to explore the relationship between the mobility of polymer molecular chains and the coarsening process of immiscible polymer blends with a co-continuous morphology under quiescent melt annealing at different temperatures. The terminal relaxation time of all neat PP and PS was determined by a rheological approach to characterize the mobility of molecular chains. A selective dissolution experiment showed that all PP/PS (50/50) blends maintained a co-continuous structure during the whole annealing process. Significant coarsening behaviors were observed for all PP/PS blends under a scanning electron microscope. A linear time dependence of the size of the PS phase was found in all PP/PS blends and the coarsening phenomenon was more obvious with the decrease of the terminal relaxation time of the PS phase because of the increase of the mobility of the polymer molecular chains. A direct relationship between the phase coarsening rate and the terminal relaxation time of the PS phase was found for the first time and it satisfied the equation . According to this equation, the formulae and k ∝ Mw-1 can be derived, which can provide significant information for the control of the phase coarsening process of immiscible polymer blends with a co-continuous morphology.

8.
Phys Chem Chem Phys ; 18(11): 8081-7, 2016 Mar 21.
Artigo em Inglês | MEDLINE | ID: mdl-26923428

RESUMO

In this article, the positive temperature coefficient (PTC) effect was studied for high-density polyethylene (HDPE)/carbon fiber (CF) composites. All of the samples showed a significant PTC effect during the heating processes without a negative temperature coefficient (NTC) effect, even at a temperature much higher than the melting point of the polymer matrix. An ever-increasing PTC intensity with increasing thermal cycles was observed in our study that had never been reported in previous research. The absence of a NTC effect resulted from the increased binding force between the matrix and fillers that contributed to the very special structure of CF surface. We incorporated thermal expansion theory and quantum tunneling effects to explain PTC effect. From the SEM micrographs for the HDPE/CF composites before and after the different thermal cycles, we found that the surface of CF was covered with a layer of polymer which resulted in a change in the gap length between CF and HDPE and its distribution. We believed that the gap change induced by polymer absorption on the fiber surface had a great effect on the PTC effect.

9.
Phys Chem Chem Phys ; 18(44): 30452-30461, 2016 Nov 09.
Artigo em Inglês | MEDLINE | ID: mdl-27781215

RESUMO

The formation of a hybrid shish-kebab (HSK) structure with different degrees of lamellar orientations was first observed in the solution crystallization of polyethylene (PE) in the presence of carbon nanofibers (CNFs). In this study, PE crystal lamellae were periodically decorated on the surface of CNFs and were aligned approximately perpendicular to the long axes of the CNFs, forming aligned hybrid shish-kebab nanostructures. More importantly, the fascinating structure was directly formed in all regions of the injection molded bars of HDPE/CNF composites, via a gas-assisted injection molding (GAIM), instead of the shell-core structure. In the GAIM process, an intense shear was imposed onto the melt during the melt second flow and drove PE chains to orient along the axes of the CNFs. Then the entropy penalty for PE chains deposited on the CNF surface was drastically decreased. Although the attractive van der Waals interactions were weak, the oriented PE chains could successfully adsorb on the CNF surface due to the decrease of the entropy penalty, therewith the underlayer coating was formed along the axis based on a two-dimensional mode for early nucleation on the CNF surface. Subsequently, subglobules appeared on the ordered structure, which could be regarded as the crystal nucleus. Finally, the oriented PE chains began to epitaxially grow from the subglobules with a folded-chain shape to decrease the polymer surface energy and grew perpendicular to the CNFs long axis, abiding by the "soft epitaxy" crystallization mechanism regardless of strict lattice matching.

10.
J Hazard Mater ; 471: 134356, 2024 Jun 05.
Artigo em Inglês | MEDLINE | ID: mdl-38643579

RESUMO

Exposure to N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine quinone (6-PPDQ) caused toxicity on Caenorhabditis elegans, including reproductive toxicity. However, the underlying mechanisms for this induced reproductive toxicity by 6-PPDQ remain largely unclear. We examined possible association of ferroptosis activation with reproductive toxicity of 6-PPDQ. In 1-100 µg/L 6-PPDQ exposed nematodes, Fe2+ content was increased, which was accompanied with enhanced lipid peroxidation, increased malonydialdehyde (MDA) content, and decreased L-glutathione (GSH) content. Exposure to 1-100 µg/L 6-PPDQ decreased expressions of ftn-1 encoding ferritin, ads-1 encoding AGPS, and gpx-6 encoding GPX4 and increased expression of bli-3 encoding dual oxidase. After 6-PPDQ exposure, RNAi of ftn-1 decreased ads-1 and gpx-6 expressions and increased bli-3 expression. RNAi of ftn-1, ads-1, and gpx-6 strengthened alterations in ferroptosis related indicators, and RNAi of bli-3 suppressed changes of ferroptosis related indicators in 6-PPDQ exposed nematodes. Meanwhile, RNAi of ftn-1, ads-1, and gpx-6 induced susceptibility, and RNAi of bli-3 caused resistance to 6-PPDQ reproductive toxicity. Moreover, expressions of DNA damage checkpoint genes (clk-2, mrt-2, and hus-1) could be increased by RNAi of ftn-1, ads-1, and gpx-6 in 6-PPDQ exposed nematodes. Therefore, our results demonstrated activation of ferroptosis in nematodes exposed to 6-PPDQ at environmentally relevant concentrations, and this ferroptosis activation was related to reproductive toxicity of 6-PPDQ.


Assuntos
Proteínas de Caenorhabditis elegans , Caenorhabditis elegans , Ferroptose , Reprodução , Animais , Caenorhabditis elegans/efeitos dos fármacos , Caenorhabditis elegans/genética , Ferroptose/efeitos dos fármacos , Reprodução/efeitos dos fármacos , Proteínas de Caenorhabditis elegans/genética , Proteínas de Caenorhabditis elegans/metabolismo , Fenilenodiaminas/toxicidade , Peroxidação de Lipídeos/efeitos dos fármacos , Glutationa/metabolismo
11.
Toxics ; 12(6)2024 Jun 07.
Artigo em Inglês | MEDLINE | ID: mdl-38922100

RESUMO

Transgenerational nanoplastic toxicity could be detected in Caenorhabditis elegans after exposure at the parental generation (P0-G); however, the underlying mechanisms remain largely unclear. We aimed to examine the role of germline nuclear hormone receptors (NHRs) in controlling the transgenerational toxicity of polystyrene nanoparticles (PS-NPs) based on gene expression screening and functional analysis. Among germline NHR genes, daf-12, nhr-14, and nhr-47 expressions were increased and nhr-12 expression was decreased by PS-NPs (1 and 10 µg/L). Transgenerational alterations in expressions of these four NHR genes were also induced by PS-NPs (1 and 10 µg/L). RNAi of daf-12, nhr-14, and nhr-47 caused resistance, whereas RNAi of nhr-12 conferred susceptibility to transgenerational PS-NP toxicity. After PS-NP exposure, expressions of ins-3, daf-28, and ins-39 encoding insulin ligands, efn-3 encoding Ephrin ligand, and lin-44 encoding Wnt ligand, as well as expressions of their receptor genes (daf-2, vab-1, and/or mig-1), were dysregulated by the RNAi of daf-12, nhr-14, nhr-47, and nhr-12. Therefore, alteration in certain germline NHRs could mediate the induction of transgenerational nanoplastic toxicity by affecting secreted ligands and their receptors in the offspring of exposed organisms.

12.
ACS Appl Mater Interfaces ; 16(6): 7939-7949, 2024 Feb 14.
Artigo em Inglês | MEDLINE | ID: mdl-38300761

RESUMO

Flexible electronics capable of acquiring high-precision signals are in great demand for the development of the internet of things and intelligent artificial. However, it is currently a challenge to simultaneously achieve high signal linearity and sensitivity for stretchable resistive sensors over a wide strain range toward advanced application scenarios requiring high signal accuracy, e.g., sophisticated physiological signal discrimination and displacement measurement. Herein, a film strain sensor, which has an electrical and mechanical dual heterostructure, was fabricated via a direct near-field electrowriting and molecule-guided in situ growth of silver nanoparticles with different concentrations on high-modulus polystyrene domains and low-modulus styrene-butadiene copolymers with a salami-like morphology. Mechanism analyses from both theoretical and experimental investigations reveal that the salami-like heteromodulus microstructure regulates microcrack propagation routes, while the heteroconductivity changes the electron transport paths and amplifies the resistance increase during crack propagation. Therefore, the as-designed strain sensor shows a linear resistive response within ca. 70% strain with a gauge factor of 25, unveiling a simple and scalable strategy for trading off signal linearity and sensitivity over a wide strain range for the fabrication of high-performance linear strain sensors.

13.
ACS Appl Mater Interfaces ; 16(13): 16809-16819, 2024 Apr 03.
Artigo em Inglês | MEDLINE | ID: mdl-38502907

RESUMO

Polymers/polymer matrix composites possessing low dielectric constants (low-k polymer dielectrics) contribute to the advance of electronics, for instance, microprocessor chips, mobile phone antennas, and data communication terminals. However, the intrinsic long-chain structural characteristic results in poor thermal conductivities, which draw heat accumulation and undermine the outstanding low-k performance of polymers. Herein, multisource free-volume effects that combine two novel kinds of extra free volume with the known in-cage free volume of polyhedral oligomeric silsesquioxanes (POSSs) are discussed to reduce the capacity for dielectric constant reduction. The multisource free-volume effects of POSSs are associated with the thermal conductive network formed by the hexagonal boron nitride (BN) in the polymer matrix. The results show a decent balance between low-k performance (dielectric constant is 2.08 at 1 MHz and 1.98 at 10 GHz) and thermal conductivity (0.555 W m-1 K-1, 4.91 times the matrix). The results provide a new idea to maximize the free-volume effects of POSSs to optimize dielectric properties together with other desired performances for the dielectrics.

14.
Sci Total Environ ; 870: 161873, 2023 Apr 20.
Artigo em Inglês | MEDLINE | ID: mdl-36731544

RESUMO

Land use change caused by urbanization is widely believed to be the primary way human activities affect energy use and, thus, CO2 emissions (CEs) in China. However, there is a limited understanding of the role of land use with detailed categories in energy-related CEs is still absent. This paper aims to narrow the knowledge gap using multi-dimension metrics, including land use scale, mixture, and intensity. These metrics were derived from three years of sequential POI data. A GWR analysis was carried out to examine the associations between land use change and energy-related CEs. Our results show that (1) the scale of most land use types exerted a bidirectional effect on CEs, demonstrating apparent spatiotemporal heterogeneity; (2) land use mixture of mature city agglomerations had a significant suppressive effect on CEs, suggesting mixed land use be advocated in the urbanization process; (3) Land use intensity had a bi-directional association with CEs in most cities, but its adverse effect gradually spread from the west to the northeast. Therefore, systematically regulating land transaction to control land scale, appropriately interplanting biofuel plants, and utilizing renewable energy are encouraged to reduce energy footprints and mitigate CEs in China. The findings and conclusions of this paper enhance our knowledge on the relationship between land use and CEs and present the scientific basis for policy-making in building low-carbon cities in the context of rapidly urbanizing China.

15.
Sci Rep ; 13(1): 6469, 2023 04 20.
Artigo em Inglês | MEDLINE | ID: mdl-37081023

RESUMO

Rural mobility inequality is an important aspect of inequality-focused Sustainable Development Goals. To reduce inequality and promote global sustainable development, more insight is needed into human mobility patterns in rural areas. However, studies on rural human mobility are scarce, limiting our understanding of the spatial and social gaps in rural human mobility and our ability to design policies for social equality and global sustainable development. This study, therefore, explores human mobility patterns in rural China using mobile phone data. Mapping the relative frequency of short-distance trips across rural towns, we observed that geographically peripheral populations tend to have a low percentage of short-distance flows. We further revealed social gaps in mobility by fitting statistical models: as travel distances increased, human movements declined more rapidly among vulnerable groups, including children, older people, women, and low-income people. In addition, we found that people living with low street density, or in rural towns in peripheral cities with long distances to city borders, are more likely to have low intercity movement. Our results show that children, older adults, women, low-income individuals, and geographically peripheral populations in rural areas are mobility-disadvantaged, providing insights for policymakers and rural planners for achieving social equality by targeting the right groups.


Assuntos
Big Data , Telefone Celular , Criança , Feminino , Humanos , Idoso , Dinâmica Populacional , População Rural , China
16.
Int J Health Policy Manag ; 12: 6653, 2023.
Artigo em Inglês | MEDLINE | ID: mdl-36243946

RESUMO

Several methods have been applied to measure healthcare accessibility, ie, the Euclidean distance, the network distance, and the transport time based on speed limits. However, these methods generally produce less accurate estimates than actual measurements. This research proposed a method to estimate historical healthcare accessibility more accurately by using taxi Global Positioning System (GPS) traces. The proposed method's advantages were evaluated vis a case study using acute myocardial infarction (AMI) cases in Beijing in 2008. Comparative analyses of the new measure and three conventionally used measures suggested that the median estimated transport time to the closest hospital with percutaneous coronary intervention (PCI) capability for AMI patients was 5.72 minutes by the taxi GPS trace-based measure, 2.42 minutes by the network distance-based measure, 2.28 minutes by the speed limit-based measure, 1.73 minutes by the Euclidean distance-based measure; and the estimated proportion of patients who lived within 5 minutes of a PCI-capable hospital was 38.17%, 89.20%, 92.52%, 95.05%, respectively. The three conventionally used measures underestimated the travel time cost and overestimated the percentage of patients with timely access to healthcare facilities. In addition, the new measure more accurately identifies the areas with low or high access to healthcare facilities. The taxi GPS trace-based accessibility measure provides a promising start for more accurately estimating accessibility to healthcare facilities, increasing the use of medical records in studying the effects of historical healthcare accessibility on health outcomes, and evaluating how accessibility to healthcare changes over time.


Assuntos
Infarto do Miocárdio , Intervenção Coronária Percutânea , Humanos , Acessibilidade aos Serviços de Saúde , Pequim , Fatores de Tempo , Infarto do Miocárdio/terapia
17.
ACS Appl Mater Interfaces ; 15(48): 55723-55733, 2023 Dec 06.
Artigo em Inglês | MEDLINE | ID: mdl-37992260

RESUMO

The distinctive thermal energy storage properties of phase change materials (PCMs) are critical for solving energy issues. However, their inherently low thermal conductivity and limited energy conversion capability impede their applications in advanced thermal energy harvesting and storage systems. Herein, we developed magnetic composite PCMs with enhanced thermal conductivity for anisotropic photothermal and magnetic-to-thermal energy conversions. The hierarchically interconnected ferroferric oxide-coated boron nitride/poly(vinyl alcohol) (BN@Fe3O4/PVA) porous scaffolds were constructed by a unidirectional freeze-casting method to enhance the directional heat transfer capability of the composite PCMs with a through-plane thermal conductivity of 1.84 W m-1 K-1 at a BN@Fe3O4 loading of 25.4 wt %. The superparamagnetic Fe3O4 nanoparticles endow the composite PCMs with unique solar absorption and magnetic response properties, and the energy conversion efficiency can be regulated by controlling the orientation of the synthesized magnetic particles in the composite PCMs. As a consequence, the resulting composite PCMs exhibit superior photo/magnetic-to-thermal energy conversion efficiency along the direction of orientation of magnetic particles. These novel findings provide an instructive guide to yield composite PCMs for efficient energy conversion.

18.
J Transp Health ; 25: 101354, 2022 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-35251936

RESUMO

BACKGROUND: Individuals have experienced various degrees of accessibility loss during the COVID-19 pandemic, which may consequently have influenced their mental health. Although efforts have been made to understand the mental health consequences of the pandemic and corresponding containment measures, the impacts of accessibility loss remain underexplored. METHODS: Based on 186 family interviews, a 569-respondent panel survey was designed and distributed monthly from February to October 2020 in Kunming, China. A 3-wave cross-lagged panel model was developed to understand the causal relationship between mental health and perceived accessibility of daily necessities, key services, and social activities. RESULTS: Goodness-of-fit indicators imply that the hypothesised model fits the observed data well: χ2/df = 2.221, AGFI = 0.910, NFI = 0.907, CFI = 0.933, RMSEA = 0.052. The results indicate that perceived accessibility of daily necessities and social activities had lagged effects on mental health status. The within-wave effects show that perceived accessibility of daily necessities (0.619, p < 0.01) and social activities (0.545, p < 0.01) significantly influenced respondents' mental health during the peak of the pandemic whilst perceived accessibility of social activities dominantly influenced their mental health after restrictions were lifted (0.779, p < 0.01). Perceived accessibility of public services such as healthcare did not significantly influence respondents' mental health in any wave. COVID-19 containment policies had different mental outcomes across population groups. Disadvantaged people experienced mental health issues due to accessibility loss for daily necessities and social activities until the lifting of compulsory QR-code-for-buses, whilst better-off populations had better mental health during the early phase of the outbreak and rapidly recovered their mental health after mobility restrictions eased. CONCLUSION: Reduced perceived accessibility of daily necessities and social activities may be an underlying cause of mental health problems. Relative accessibility deprivation exacerbated mental health inequities during the COVID-19 pandemic.

19.
Appl Spectrosc ; 76(9): 1068-1079, 2022 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-35583031

RESUMO

In order to extract useful information from X-ray fluorescence (XRF) spectra and establish a high-accuracy prediction model of soil heavy metal contents, a hybrid model combining a deep belief network (DBN) with a tree-based model was proposed. The DBN was first introduced into feature extraction of XRF spectral data, which can obtain deep layer features of spectra. Owing to the strong regression ability of the tree-based model, it can offset the deficiency of DBN in prediction ability so it was used for predicting heavy metal contents based on the extracted features. In order to further improve the performance of the model, the parameters of model can be optimized according to the prediction error, which was completed by sparrow search algorithm and the gird search. The hybrid model was applied to predict the contents of As and Pb based on spectral data of overlapping peaks. It can be obtained that R2 of As and Pb reached 0.9884 and 0.9358, the mean square error of As and Pb are as low as 0.0011 and 0.0058, which outperform other commonly used models. That proved the combination of DBN and tree-based model can obtain more accurate prediction results.


Assuntos
Metais Pesados , Solo , Algoritmos , Chumbo
20.
ACS Appl Mater Interfaces ; 14(46): 52411-52421, 2022 Nov 23.
Artigo em Inglês | MEDLINE | ID: mdl-36370386

RESUMO

Phase change materials (PCMs) as one of the most potential latent heat storage techniques have been widely used for thermal management and energy storage. However, simultaneously imparting flexibility, high thermal conductivity, and considerable energy storage density to organic PCMs remains challenging. In this work, a coupling strategy combining substance exchange and magnetic orientation has been proposed to fabricate phase change gels (PCGs) with thermally induced flexibility and high through-plane thermal conductivity. In the PCGs, synthesized boron nitride/ferroferric oxide (BN@Fe3O4) particles and polyacrylic acid (PAA) precursor liquid are introduced to polyethylene glycol (PEG) aqueous solution, and a magnetic field is applied in the process of PAA network construction to promote ordered arrangement of BN@Fe3O4 along the direction of the magnetic field. Consequently, PEG is wrapped by the cross-linked PAA supporting network, forming PCGs with excellent shape stability and thermally induced flexibility. The vertical orientation structure of BN@Fe3O4 endows the PCGs with an enhanced through-plane thermal conductivity of up to 1.07 W m-1 K-1 at a BN@Fe3O4 loading of 25.6 wt % with an additional enhancement of 215% compared to the composite without BN. The thermally conductive leakage-proof PCGs present great application potential in heat storage and management.

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