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Reining in deformation twinning is crucial for the mechanical properties of hexagonal close-packed (HCP) metals and hinges on an explicit understanding of the twinning nucleation mechanism. Unfortunately, it is often suggested rather than conclusively demonstrated that twinning nucleation can be mediated by pure atomic shuffles. Herein, by utilizing in situ high-resolution transmission electron microscopy, we have dissected the atomic shuffling mechanism during the {101Ì 2} twinning nucleation in rhenium nanocrystals, which revealed the emergence of an intermediate body-centered tetragonal (BCT) structure. Specifically, the double-layered prismatic planes initially shuffle into single-layered {11Ì 0}BCT planes; subsequently, adjacent {22Ì 0}BCT planes shuffle in opposite directions to form the basal planes of the twin embryo. This shuffling mechanism is further corroborated by molecular dynamic simulations. The finding provides direct evidence of shuffle-dominated twinning nucleation with atomic details that may lead to better control of this critical twinning mode in HCP metals.
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The service of high-strength steel suffers from the threat of hydrogen embrittlement and introducing nano-precipitates is an effective avenue to mitigate it. How hydrogen atoms migrate into nano-precipitates is an important question that needs to be clarified. In this study, NEB-based DFT calculations have clearly constructed the energy evolution profiles of the whole process for hydrogen atoms diffusing from α-Fe through the α-Fe/MC (M = V, Ti, Nb) coherent interfaces and finally into the nano-precipitates. The calculation results indicate that a hydrogen atom migrates with difficulty through the α-Fe/MC coherent interfaces and the diffusions in nano-precipitates follow two-step pathways. The C atom vacancy is easier to form in MC nano-precipitates. When introducing a C atom or metallic atom vacancy into the α-Fe/MC interface, the C atom vacancy is the hydrogen trapping site, while the metallic atom vacancy reduces the migration barrier. In addition, once a C atom or metallic atom vacancy is formed in the nano-precipitate, the vacancy will behave as an irreversible trapping site. Finally, electronic structure analyses and distortion energy calculations clearly reveal the effects of the local atomic environment on hydrogen diffusion from α-Fe into nano-precipitates.
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This study aims to systematically review the efficacy and safety of different traditional Chinese medicine injections combined with conventional treatment for patients with post-acute myocardial infarction heart failure. The relevant randomized controlled trial(RCT) was retrieved from CNKI, Wanfang, VIP, SinoMed, PubMed, EMbase, and Cochrane Library with the time interval from inception to May 13, 2023. Two reviewers independently screened the literature, extracted data, and assessed the risk of bias of the included studies. Network Meta-analysis was then performed in RevMan 5.3 and Stata 15.1. A total of 68 RCTs involving 11 traditional Chinese medicine injections and 5 995 patients were included. The results were explained based on the surface under the cumulative ranking curve(SUCRA).(1) In terms of reducing major adverse cardiovascular event(MACE), the therapies followed the trend of Xinmailong Injection+conventional treatment(83.8%) > Yiqi Fumai Injection+conventional treatment(57.1%) > Xuebijing Injection+conventional treatment(56.6%) > Shenmai Injection+conventional treatment(53.1%) > Shenfu Injection+conventional treatment(45.3%) > conventional treatment(4.0%).(2) In terms of increasing left ventricular ejection fraction(LVEF), the therapies followed the trend of Yiqi Fumai Injection+conventional treatment(84.0%) > Shenmai Injection+conventional treatment(69.6%) > Shenfu Injection+conventional treatment(62.7%) > Xinmailong Injection+conventional treatment(61.6%) > Shuxuening Injection+conventional treatment(54.8%) > Shenqi Fuzheng Injection+conventional treatment(46.7%) > Shengmai Injection+conventional treatment(45.9%) > Breviscapine Injection+conventional treatment(39.9%) > Danhong Injection+conventional treatment(38.8%) > Huangqi Injection+conventional treatment(38.7%) > conventional treatment(7.3%).(3) In terms of reducing B-type natriuretic peptide(BNP), the therapies followed the trend of Xinmailong Injection+conventional treatment(98.6%) > Shenmai Injection+conventional treatment(57.7%) > Shenfu Injection+conventional treatment(52.5%) > Shengmai Injection+conventional treatment(30.1%) > conventional treatment(11.0%).(4) In terms of reducing cardiac troponin â (cTnâ ), the therapies followed the trend of Shenmai Injection+conventional treatment(92.3%) > Yiqi Fumai Injection+conventional treatment(61.5%) > Shenfu Injection+conventional treatment(51.2%) > Shengmai Injection+conventional treatment(48.1%) > Xinmailong Injection+conventional treatment(26.6%) > conventional treatment(20.3%).(5) In terms of reducing high-sensitivity C-reactive protein(hs-CRP), the therapies followed the trend of Shenmai Injection+conventional treatment(79.9%) > Xinmailong Injection+conventional treatment(68.1%) > Shenfu Injection+conventional treatment(63.1%) > Xuebijing Injection+conventional treatment(56.7%) > Shengmai Injection+conventional treatment(51.1%) > Shenqi Fuzheng Injection+conventional treatment(42.8%) > Huangqi Injection+conventional treatment(34.7%) > conventional treatment(3.5%).(6) A total of 22 RCTs reported the occurrence of adverse reactions, mainly involving the damage of the circulatory system, digestive system, and coagulation function. The current evidence suggested that Xinmailong Injection+conventional treatment may have the best therapeutic effect in reducing MACE and BNP; Yiqi Fumai Injection+conventional treatment may be the best in increasing LVEF; Shenmai Injection+conventional treatment may be the best in reducing cTnI and hs-CRP. The safety needs further quantitative research and analysis. However, more high-quality RCT is required to validate the above conclusions due to limitations in the quality and quantity of the included studies.
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Medicamentos de Ervas Chinesas , Insuficiência Cardíaca , Infarto do Miocárdio , Humanos , Medicina Tradicional Chinesa , Volume Sistólico , Metanálise em Rede , Proteína C-Reativa , Função Ventricular Esquerda , Medicamentos de Ervas Chinesas/efeitos adversos , Infarto do Miocárdio/tratamento farmacológico , Insuficiência Cardíaca/tratamento farmacológicoRESUMO
This study reviewed the current status of the use of outcome indicators in randomized controlled trial(RCT) on traditional Chinese medicine(TCM) treatment of microvascular angina(MVA) and analyzed the existing problems and possible solutions, aiming to provide a basis for the design of high-quality RCT and the establishment of core outcome sets for MVA. CNKI, Wanfang, VIP, SinoMed, PubMed, EMbase, Cochrane Library, Web of Science, and 2 clinical trial registries were searched for the RCT on TCM treatment of MVA according to pre-defined criteria. The Cochrane's risk of bias assessment tool was used to evaluate the methodological quality of the included RCT and the use of outcome indicators was summarized. A total of 69 RCTs were included, from which 100 outcome indicators were extracted, with the frequency of 430. The extracted outcome indicators belonged to 8 domains: response rate, symptoms and signs, physical and chemical examinations, TCM efficacy, safety, quality of life, economic evaluation, and long-term prognosis. The indicators of physical and chemical examinations were the most(70 indicators with the frequency of 211), followed by those of response rate(7 indicators with the frequency of 73) and symptoms and signs(7 indicators with the frequency of 54). The outcome indicators with higher frequency were adverse reactions, angina attack frequency, clinical efficacy, endothelin-1, total duration of treadmill exercise, and hypersensitive C-reactive protein. The RCT on TCM treatment of MVA had the following problems: irregular reporting of adverse reactions, diverse indicators with low frequency, lack of attention to the application of endpoint indicators, insufficient use of TCM differentiation and efficacy indicators, non-standard evaluation criteria and failure to reflect the basic characteristics of TCM. A unified MVA syndrome differentiation standard should be established, on the basis of which an MVA treatment efficacy evaluation system and core outcome indicator set that highlights the characteristics of TCM with patient-reported outcomes as the starting point should be established to improve the clinical research and research value.
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Medicamentos de Ervas Chinesas , Angina Microvascular , Humanos , Medicina Tradicional Chinesa , Medicamentos de Ervas Chinesas/efeitos adversos , Angina Microvascular/tratamento farmacológico , Qualidade de Vida , Fitoterapia , Resultado do TratamentoRESUMO
This study aims to mine the regularity of traditional Chinese medicine(TCM) prescriptions for sick sinus syndrome(SSS) and provide a reference for clinical syndrome differentiation and treatment. The relevant papers were retrieved from CNKI, Wanfang, VIP, and SinoMed with the time interval from inception to January 31, 2023. The relevant information from qualified papers was extracted to establish a library. Lantern 5.0 and Rstudio were used to analyze the latent structure and association rules of TCMs with the frequency ≥3%, which combined with frequency descriptions, were used to explore the rules of TCM prescriptions for SSS. A total of 192 TCM prescriptions were included, involving 115 TCMs with the cumulative frequency of 1 816. High-frequency TCMs include Aconiti Lateralis Radix Praeparata, Ginseng Radix et Rhizoma, Glycyrrhizae Radix et Rhizoma, Astragali Radix, and Salviae Miltiorrhizae Radix et Rhizoma. The high-frequency medicines mainly had the effects of tonifying, releasing exterior with pungent-warm, and activating blood and resolving stasis. The analysis of the latent structure model yielded 13 hidden variables, 26 hidden classes, 8 comprehensive cluster models, and 21 core prescriptions. Accordingly, the common syndromes of SSS were inferred as heart-Yang Qi deficiency, heart-spleen Yang deficiency, heart-kidney Yang deficiency, Yang deficiency and blood stasis, both Qi and Yin deficiency and blood stasis, and Yin and Yang deficiency. The analysis of association rules predicted 30 strong association rules, among which Ginseng Radix et Rhizoma-Aconiti Lateralis Radix Praeparata had the highest support. SSS is a syndrome with Yang deficiency and Qi deficiency as the root causes and cold, phlegm, and stasis as the manifestations. The clinical treatment of SSS should focus on warming Yang and replenishing Qi, which should be supplemented with the therapies of activating blood and resolving stasis, warming interior and dissipating cold, or regulating Qi movement for resolving phlegm according to the patients' syndromes.
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Aconitum , Medicamentos de Ervas Chinesas , Panax , Humanos , Síndrome do Nó Sinusal/tratamento farmacológico , Deficiência da Energia Yang/tratamento farmacológico , Medicamentos de Ervas Chinesas/farmacologia , Medicina Tradicional Chinesa , Prescrições , Rizoma/químicaRESUMO
The structural design of photocatalysts is highly related to the separation and transfer of photogenerated carriers, which is essential for the improvement of photocatalytic hydrogen evolution performance. Here, the hybrid photocatalyst M@NCNT@ZIS (M: Fe, Co, Ni; NCNT: nitrogen-doped carbon nanotube; ZIS: ZnIn2 S4 ) with a hierarchical structure is rationally designed and precisely synthesized. The unique hollow structure with a large specific surface area offers abundant reactive sites, thus increasing the adsorption of reactants. Importantly, the properly positioned metal nanoparticles realize the directional charge migration from ZIS to M@NCNT, which significantly improves the efficiency of charge separation. Furthermore, the intimate interface between M@NCNT and ZIS effectively facilitates charge migration by shortening the transfer distance and providing numerous transport channels. As a result, the optimized Co@NCNT@ZIS exhibits a remarkable photocatalytic hydrogen evolution efficiency (43.73 mmol g-1 h-1 ) without Pt as cocatalyst. Experimental characterizations and density functional theory calculations demonstrate that the synergistic effect between hydrogen adsorption and interfacial charge transport is of great significance for improving photocatalytic hydrogen production performance.
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Although rare-earth nickelates (ReNiO3, Re ≠ La) exhibit abundant electronic phases and widely adjustable metal to insulator electronic transition properties, their practical electronic applications are largely impeded by their intrinsic meta-stability. Apart from elevating the oxygen reaction pressure, heterogeneous nucleation is expected to be an alternative strategy that enables the crystallization of ReNiO3 at low meta-stability. In this work, the respective roles of high oxygen pressure and heterogeneous interface in triggering ReNiO3 thin film growth in the metastable state are revealed. ReNiO3 (Re = Nd, Sm, Eu, Gd and Dy) thin films grown on a LaAlO3 single crystal substrate show effective crystallization at atmospheric pressure without the necessity to apply high oxygen pressure, suggesting that the interfacial bonding between the ReNiO3 and substrates can sufficiently reduce the positive Gibbs formation energy of ReNiO3, which is further verified by the first-principles calculations. Nevertheless, the abrupt electronic transitions only appear in ReNiO3 thin films grown at high oxygen pressure, in which case the oxygen vacancies are effectively eliminated via high oxygen pressure reactions as indicated by near-edge X-ray absorption fine structure (NEXAFS) analysis. This work unveils the synergistic effects of heterogeneous nucleation and high oxygen pressure on the growth of high quality ReNiO3 thin films.
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AIM: To investigate whether a novel decision support tool would effectively minimize physical restraint use in critically ill adult patients. DESIGN: A nonequivalent quasi-experimental design combined with a descriptive qualitative approach was used. METHODS: A Restraint Decision Tree was developed based on a qualitative study that explored the barriers to employ the Restraint Decision Wheel. During the quasi-experimental study, patients admitted to the unit between October 2017 and March 2018 were enrolled as the control group receiving the Restraint Decision Wheel (n = 528), whereas patients between April 2018 and September 2018 were enrolled as the intervention group receiving the Restraint Decision Tree (n = 564). The physical restraint rate, accidental catheter removal rate and nurses' satisfaction were compared. RESULTS: The Restraint Decision Tree significantly decreased physical restraint use. No significant difference in the rate of accidental catheter removal was found. Nurses reported increased satisfaction with the restraint decision-making. CONCLUSIONS: The Restraint Decision Tree could minimize physical restraint use. Physicians' involvement in the restraint decision-making and nurses' competence in delirium assessment may be essential for successful implementation of the Restraint Decision Tree.
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Estado Terminal , Restrição Física , Adulto , Humanos , Unidades de Terapia Intensiva , Pesquisa Qualitativa , Restrição Física/efeitos adversosRESUMO
In this study, the evidence mapping was employed to systematically analyze the clinical research literature and learn the distribution of evidence on the prevention and treatment of essential hypertension with Chinese patent medicines in recent six years. CNKI, Wanfang, VIP, SinoMed, PubMed, and Cochrane Library were searched for the relevant literature published from January 2016 to December 2021. The distribution characteristics of evidence were analyzed and presented in charts combined with words. A total of 263 studies were selected, including 238 intervention studies, 17 systematic reviews/Meta-analysis, and 8 observation studies. A total of 72 Chinese patent medicines were involved, among which Songling Xuemaikang Capsules had the highest frequency. In China, the attention to the treatment of essential hypertension with Chinese patent medicines was insufficient, as manifested by the declining number of published literature and the low quality of studies. There were cases of off-label use and medication without syndrome differentiation in clinical practice. Some outcome indicators failed to embody the characteristics of traditional Chinese medicine and there were cases ignoring the end-point outcome indicators. The overall quality of systematic reviews/Meta-analysis was low, and a variety of studies failed to draw valid conclusions. In the future, it is necessary to standardize the clinical medication and improve the quality of randomized controlled trial(RCT), so as to produce high-quality evidence-based medical evidence and provide strong support for the efficacy and safety of Chinese patent medicines in the prevention and treatment of essential hypertension.
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Medicamentos de Ervas Chinesas , Medicamentos sem Prescrição , Humanos , Povo Asiático , Medicamentos de Ervas Chinesas/uso terapêutico , Hipertensão Essencial/tratamento farmacológico , Medicina Tradicional Chinesa , Medicamentos sem Prescrição/uso terapêutico , Revisões Sistemáticas como Assunto , Metanálise como AssuntoRESUMO
The popularity of Internet technology has resulted in people's lives being increasingly embedded in this network. The rise in usage of environmental protection apps has become a powerful tool in driving offline environmental protection activities and green lifestyles. However, little is known about the public's online green behavior. To fill this gap, we took Ant Forest, the most influential online environmental protection project in China, as a case study to explore the driving psychology of Ant Forest users' continuous use behaviors (CUBs) by expanding the use and gratifications theory. The proposed hypotheses were tested using a structural equation model based on data from 951 Ant Forest users. The results showed that users' gratification is an important psychological motivation that encourages CUBs in Ant Forest, and the different dimensions of gratification have significant differences in the driving intensity of the three types of CUBs. Moreover, emotional dependence moderates the relationships between gratifications and CUBs. Finally, from the perspective of cultivating gratification, this study suggests promoting the continuous use of Ant Forest as it provides a reference for understanding and developing online green behavior.
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Formigas , Animais , China , Conservação dos Recursos Naturais , Florestas , Humanos , PrazerRESUMO
Semiconductor quantum dots (QDs) in conjunction with non-noble 3d-metal ions (e.g., Fe3+, Co2+, and Ni2+) have emerged as an extremely efficient, facile, and cost-effective means of solar-driven hydrogen (H2) evolution. However, the exact structural change of the active sites under realistic conditions remains elusive, and the mechanism of H2 evolution behind the remarkable activity is poorly understood. Here, we successfully track the structural variation of the catalytic sites in the typical H2 photogeneration system consisting of CdSe/CdS QDs and 3d-metal ions (i.e., Ni2+ used here). That is, the nickel precursor of Ni(OAc)2 changes to Ni(H2O)62+ in neutral H2O and eventually transforms to Ni(OH)2 nanosheets in alkaline media. Furthermore, the in operando spectroscopic techniques of electron paramagnetic resonance and X-ray absorption spectroscopy reveal the photoinduced transformation of Ni(OH)2 to a defective structure [Nix0/Ni1-x(OH)2], which acts as the real catalytic species of H2 photogeneration. Density functional theory (DFT) calculations further indicate that the surface Ni-vacancies (VNi) on the Ni(OH)2 nanosheets enhance the adsorption and dissociation of H2O molecules to enhance the local proton concentration, while the Ni0 clusters behave as H2-evolution sites, thereby synergistically promoting the activity of H2 photogeneration in alkaline media.
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Microemulsions exist widely in nature, daily life and industrial manufacturing processes, including petroleum production, food processing, drug delivery, new material fabrication, sewage treatment, etc. The mechanical properties of microemulsion droplets and a correlation to their molecular structures are of vital importance to those applications. Despite studies on their physicochemical determinants, there are lots of challenges of exploring the mechanical properties of microemulsions by experimental studies. Herein, atomistic modelling was utilized to study the stability, deformation, and rupture of Janus oligomer enabled water-in-oil microemulsion droplets, aiming at revealing their intrinsic relationship with Janus oligomer based surfactants and oil structures. The self-emulsifying process from a water, oil and surfactant mixture to a single microemulsion droplet was modulated by the amphiphilicity and structure of the surfactants. Four microemulsion systems with an interfacial thickness in the range of 7.4-17.3 Å were self-assembled to explore the effect of the surfactant on the droplet morphology. By applying counter forces on the water core and the surfactant shell, the mechanical stability of the microemulsion droplets was probed at different ambient temperatures. A strengthening response and a softening regime before and after a temperature-dependent peak force were identified followed by the final rupture. This work demonstrates a practical strategy to precisely tune the mechanical properties of a single microemulsion droplet, which can be applied in the formation, de-emulsification, and design of microemulsions in oil recovery and production, drug delivery and many other applications.
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Ammonia synthesis is one of the most studied reactions in heterogeneous catalysis. To date, however, electrochemical N2 reduction in aqueous systems has proven to be extremely difficult, mainly due to the competing hydrogen evolution reaction (HER). Recently, it has been shown that transition metal complexes based on molybdenum can reduce N2 to ammonia at room temperature and ambient pressure in a non-aqueous system, with a relatively small amount of hydrogen output. We demonstrate that the non-aqueous proton donor they have chosen, 2,6-lutidinium (LutH+), is a viable substitute for hydronium in the electrochemical process at a solid surface, since this donor can suppress the HER rate. We also show that the presence of LutH+ can selectively stabilize the *NNH intermediate relative to *NH or *NH2via the formation of hydrogen bonds, indicating that the use of non-aqueous solvents can break the scaling relationship between limiting potential and binding energies.
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We investigate the effect of Cr-doping on the properties of α-Fe2O3(001) thin films with Fe termination using the local density approximation plus a Hubbard U correction. We find that both the doping site and concentration of Cr atoms dramatically affect the electronic structure and work function (WF) of α-Fe2O3 films. The results demonstrate that it is most energetically favorable for Cr atoms to substitute the Fe atoms in the sub-surface of α-Fe2O3 thin films. The doping of Cr atoms in the sub-surface not only lowers the band gap of the film but also greatly enhances the work function by 0.9 eV with respect to the pure α-Fe2O3 film. The increase of WF correlates with the reduction of occupied O px/py states at the top valence band which leads to a decrease of the Fermi energy. As the Cr concentration changes from 4.2% to 16.7%, the WF firstly increases, and then drops. The WF reaches a maximum of 6.61 eV for the Cr concentration of 8.3%. These results suggest that doping Cr atoms in a α-Fe2O3(001) thin film can increase the corrosion potential and benefits the protection of steel from corrosion.
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Solid films are considered as typical model systems to study size effects on thermal vacancy concentration in nanomaterials. By combining the generalized Young-Laplace equation with the chemical potential of vacancies, a strict size-dependent thermodynamic model of vacancies, which includes the surface intrinsic elastic parameters of the eigenstress, Young's modulus and the geometric size of the solid films, was established. The vacancy concentration changes in the film with respect to the bulk value, depending on the geometric size and surface stress sign of the solid films. Atomistic simulations of Au and Pt films verified the developed thermodynamic model. These results provide physical insights into the size-dependent thermal vacancy concentration in nanomaterials.
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OBJECTIVE: To study the oxidative damage and apoptosis of renal tubular epithelial cells (NRK-52e cell line) induced by ethylbenzene. METHODS: NRK-52e cells were exposed to 30, 60, 90, 120 µmol/L ethylbenzene for 24 hours. Cell viability were measured using MTT, the activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT), the contents of malondialdehyde (MDA) and glutathione (GSH) were detected respectively. PI fluorescent staining assay was applied to detect percentage of apoptosis in ethylbenzene-treated groups. RESULTS: Compared with control group, cell outline became clear, cell diopter increased, cell became smaller and shrinkage, some cells broke in 60 µmol/L ethylbenzene-treated group. Plenty of cells died, suspension cells increased significantly in 90 µmol/L ethylbenzene-treated group. Compared with control group, cell viability the activities of SOD and CAT and the content of GSH were significantly decreased in 60 and 90 µmol/L ethylbenzene-treated groups (P<0.05). The MDA content were remarkably elevated in 90 µmol/L ethylbenzene-treated groups (P<0.05). CONCLUSION: Ethylbenzene can induce oxidative stress and apoptosis in NRK-52e cells (P<0.05).
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Apoptose/efeitos dos fármacos , Derivados de Benzeno/toxicidade , Células Epiteliais/efeitos dos fármacos , Estresse Oxidativo/efeitos dos fármacos , Animais , Linhagem Celular , Células Epiteliais/metabolismo , Túbulos Renais/citologia , Oxirredução , Ratos , Espécies Reativas de Oxigênio/metabolismoRESUMO
The major public health emergencies (PHEs) represented by the COVID-19 pandemic, while posing a serious threat to human health, have led people to rethink about the harmonious relationship between humans and nature. It is worthy to explore whether and how the framework effect of event information can be used to turn crises into opportunities to promote public pro-environmental behavior (PEB). Through a pre-and post-test control experiment, this study took the COVID-19 pandemic as a case, to explore the effects of four PHE information frameworks on promoting PEB, coupled with two information loss-gain frameworks and two information content frameworks. The results showed that all four information frameworks contribute to the public PEB. However, there are differences: only the environmental gain information effect is significant for PEB in the private sphere. The environmental loss and health gain information are effective for PEB in organizations. However, in the public sphere, all four information frameworks significantly motivate PEB. Further factorial analysis revealed that the interaction between the information content and loss-gain framework was not significant, with the latter playing the dominant role. These findings provide a new approach to how to develop the information framework effect and turn crises into opportunities to promote public PEB in the context of major PHEs.
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COVID-19 , Saúde Pública , Humanos , PandemiasRESUMO
The majority of polymer-based materials demonstrate expansion upon absorbing water from the air. Mechanical metamaterials provide an interesting way to achieve unusual hygroscopic deformation. However, previous studies have only accommodated the limited tunability of negative hygroscopic expansion by theoretical analysis but have never involved other deformation modes. This work proposes modular reprogrammable 3D moisture-sensitive mechanical metamaterials with switchable hygroscopic deformation modes, which are built up of multi-material 3D-printed bi-material curved strips and cubic nodes. Depending on the geometrical parameters and spatial layouts of the curved strips, the metamaterials exhibit tunable coefficient of hygroscopic expansion from negative to positive. In addition to homogeneous deformation, complex 3D hygroscopic deformation modes can be achieved including shear and twist. More interestingly, the metamaterials are reprogrammable since all the deformation modes can be switched by modular disassembling and reassembling of the curved strips, just like LEGO building blocks. This work demonstrates a feasible approach to achieve customized 3D hygroscopic deformation through easy block building for specific engineering applications including eliminating hygroscopic stress, shape morphing structures, and smart actuators.
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Metal-organic frameworks (MOFs), as a class of semiconductor-like materials, are widely used in photocatalysis. However, the limited visible light absorption and poor charge separation efficiency are the main challenges restricting their photocatalytic performance. Herein, the type II heterojunction MIL-68(In)@ZIS was successfully fabricated by in situ growth of ZnIn2S4 (ZIS) on the surface of a representative MOF, i.e. MIL-68(In). After composition optimization, MIL-68(In)-20@ZIS shows an extraordinary photocatalytic hydrogen production efficiency of 9.09 mmol g-1 h-1 and good photochemical stability, which far exceeds those of most photocatalysts. The hierarchical loose structure of MIL-68(In)-20@ZIS is conducive to the adsorption of reactants and mass transfer. Meanwhile, a large number of tight 2D contact interfaces significantly reduce the obstruction of charge transfer, paving the way for high-perform photocatalytic hydrogen evolution. The experimental results demonstrate that the MIL-68(In)@ZIS heterojunction achieves intensive photoresponse and effective charge separation and transfer benefiting from unique charge transport paths of a type II heterojunction. This study opens an avenue toward MOF-based heterojunctions for solar energy conversion.
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The outstanding abilities of metamaterials to manipulate physical fields are extensively studied in both wave-based and diffusion-based fields. However, mass diffusion metamaterials, with the ability to manipulate diffusion with practical applications associated with chemical and biochemical engineering, have not yet been experimentally demonstrated. In this work, ion cloaking, concentrating, and selection in liquid solvents are verified by both simulations and experiments, and the concept of a "plug and switch" metamaterial is proposed based on scattering cancellation (SC) to achieve switchable functions by plugging modularized functional units into a functional motherboard. Plugging in any module barely affects the environmental diffusion field, but the module choice impacts different diffusion behaviors in the central region. Cloaking strictly hinds ion diffusion, and concentrating increase diffusion flux, while cytomembrane-like ion selection permits the entrance of some ions but blocks others. In addition, these functions are demonstrated in special applications like the catalytic enhancement by the concentrator and the protein protection by the ion selector. This work not only experimentally demonstrates the effective manipulation of mass diffusion by metamaterials, but also shows that the "plug and switch" design is extensible and reconfigurable. It facilitates novel applications including sustained drug release, catalytic enhancement, bioinspired cytomembranes, etc.