The paradox of pandemic mitigation? Moderating role of pandemic severity on the impact of social distancing policies: a cultural value perspective

Abstract Background Social distancing policies were of utmost importance during the early stages of the COVID-19 pandemic. These policies aimed to mitigate the severity of local outbreaks by altering public behavior. However, if the severity of the pandemic reduces, the impact of these policies on actual behavior may decrease. This study aims to examine, from a global perspective, whether the impact of social distancing policies on actual mobility is moderated by local pandemic severity and whether this moderating effect varies across cultural value contexts. Methods We combined multiple publicly available global datasets for structural equation model analysis. 17,513 rows of data from 57 countries included in all databases were analyzed. Multilevel moderated moderation models were constructed to test the hypotheses. Results More stringent policies in a region mean less regional mobility (β = -0.572, p < 0.001). However, the severity of local outbreaks negatively moderated this effect (β = -0.114, p < 0.001). When the pandemic was not severe, the influence of policy intensity on mobility weakened. Furthermore, based on Schwartz’s cultural values theory, cultural values of autonomy (β = -0.109, p = 0.011), and egalitarianism (β = -0.108, p = 0.019) reinforced the moderating effect of pandemic severity. On the other hand, cultural values of embeddedness (β = 0.119, p = 0.006) and hierarchy (β = 0.096, p = 0.029) attenuated the moderating effect. Conclusions Social distancing policies aim to reduce the severity of local pandemics; however, the findings reveal that mitigating local pandemics may reduce their impact. Future policymakers should be alert to this phenomenon and introduce appropriate incentives to respond. The results also show that the moderating role of pandemic severity varies across cultures. When policies are promoted to deal with global crises, policymakers must seriously consider the resistance and potential incentives of cultural values

Additional file 1 of The paradox of pandemic mitigation? Moderating role of pandemic severity on the impact of social distancing policies: a cultural value perspective

Additional file 1: Supplementary Material. Table 1. Descriptive statistics for study variables in the 57 countries. Table 2. Multilevel regression results for GSI on mobility. Table 3. Multilevel regression results for GSI*DNC on mobility. Figure 1. Conditional effect of GSI on mobility (RE) as a function of DNC. Figure 2. Average RE under GSI and DNC conditions in different periods. Table 4. Moderated moderation model of RE (the coefficients of the interaction terms). Figure 3. Conditional effect of GSI on RE as a function of DNC under different embeddedness values. Figure 4. Conditional effect of GSI on RE as a function of DNC under different autonomy values. Figure 5. Conditional effect of GSI on RE as a function of DNC under different hierarchy values. Figure 6. Conditional effect of GSI on RE as a function of DNC under different egalitarianism values. Figure 7. Conditional effect of GSI on RE as a function of DNC under different mastery values. Figure 8. Conditional effect of GSI on RE as a function of DNC under different harmony values

Potential usage of porous autoclaved aerated concrete waste as eco-friendly internal curing agent for shrinkage compensation

Autoclaved aerated concrete waste (AACW) is an inorganic porous construction and demolition waste, which is possible to be environmentally used as an internal curing agent, due to its water absorption and release characteristics. In present work, fine aggregate (sand) was replaced by AACW aggregate with the same volume for internal curing purpose. The potential curing effect of AACW was also compared with a classical internal curing agent, i.e. expanded perlite (EPA), under the same particle size condition. Results indicate that the compressive strength of AACW groups after 28-day sealing curing is basically the same as that of the control group. Compared with EPA, internal curing with AACW can better improve the internal relative humidity, reduce the autogenous shrinkage, and delay the cracking time of cement mortar. At the same time, AACW effectively refines the pore structure and improves the micro-hardness of the interfacial transition zone (ITZ) through internal curing, and enhances the resistance to chloride penetration.Web of Science320art. no. 12889

Heat-cured cement-based composites with wet-grinded fly ash and carbide slag slurry: Hydration, compressive strength and carbonation

Fly ash (FA) with high glassy phase content is a pozzolanic material with low activity, while carbide slag is a solid waste with portlandite crystals embedded in the impurity phases. Herein, wet-grinding method was used twice to improve the pozzolanic reactivity of FA and promote the dissolution of embedded calcium hydroxide in the CS as a lime source, respectively. Wet-grinded FA slurry (WFA) with D50 of 2.5 mu m and wet-grinded CS slurry (WCS) with D50 of 3.0 mu m were prepared. It was found that setting times, hydration heat release, early and late compressive strength, carbonation resistance of high volume WFA blended composites were significantly enhanced by WCS, attributed to the pre-dissolved calcium resource and alkali reserve. However, an excessive amount (12 wt%) of WCS addition causes an abnormal decrease in strength, due to the microstructure degradation by coarse portlandite crystals. Higher proportion of C-S-H might be ready for carbonation in high volume WFA blended composites, due to the promoted Al incorporation in C-S-H by wet-grinding.Web of Science307art. no. 12491

Green reaction-type nucleation seed accelerator prepared from coal fly ash ground in water environment

Fly ash is the main waste generated from coal production. The application of fly ash in building materials helps reduce pollution. In the present work, a novel reaction-type nucleation seed accelerator with D50 of 512 nm was prepared from coal fly ash using wet-grinding technology, denoted as WFA seed. The physical and chemical performances of WFA seed and its promotion effect on hydration, strength and microstructure of Portland cement (PC) were studied. With the addition of WFA seed, compressive strength was significantly increased by 50% and 16% at 12 h and 28 days. The hydration heat peak was also clearly increased by WFA seed. The hydration and strength promotion by WFA seed is attributed to the dual function of secondary reaction (which occurs as early as 12 h) and nucleation induction, which is different from the single function of nucleation site effect of some existing nano-materials. Furthermore, the main chain length and Al/Si ratio of C-S-H gel were increased, and the pore structure of cement was refined by the addition of WFA seed.Web of Science306art. no. 12484

Microstructure and mechanical properties of activated high-alumina ferronickel slag with carbide slag and alkaline salts

Alkali-activated materials have several remarkable advantages over Portland cement particularly in carbon emission and energy consumption. However, less work has focus on the feasibility of preparing geopolymers from high-alumina ferronickel slag (AFS) with alkaline salts as activators. This article reports the microstructure and mechanical properties of activated high-alumina ferronickel slag (AAFS) with a combination of carbide slag (CS) and Na2CO3 (SC) or Na2SO4 (SS). Results indicate that the AAFS pastes properties are affected by concentration (Na2O equivalent) and nature of activator. The hydration of high-alumina ferronickel slag (FNS) is accelerated as the Na2O equivalent increases from 0.5% to 3% regardless of alkaline salt type, while the early age hydration will be restricted when Na2O equivalent is higher than 3%. The pH of pore solution in SS-activated series is lower than that of SC-activated series. As such, SC-activated FNS pastes have higher exothermic heat in the initial hydration period than SS dosed specimens. Although SC activated pastes have more gel products and smaller critical pore diameter, the SS-activated specimens can achieve higher compressive strength due to compact interfacial transition zone and reasonable hydration products composition.Web of Science49art. no. 10404

Effect of wet-grinding steel slag on the properties of Portland cement: An activated method and rheology analysis

Steel slag is a solid waste generated from the steelmaking process. With a very low utilization rate of 30% in China, a high discharging cost of steel slag is inevitable so that it is imperative to dispose of steel slag by new technology. In this study, steel slag was refined by wet-grinding technology to apply on cement. The results showed that the initial setting time and final setting time were prolonged by the increased dosage of 3 mu m steel slag. Although the viscosity of wet-grinding steel slag - cement specimens increased significantly, the shear-thinning phenomenon happened by mechanical mixing. The wet-grinding specimens presented a higher hydration heat than that of raw steel slag specimens, and the microstructure of 3 mu m-40% (3 mu m steel slag mixed with cement as a dosage of 40%) is much denser and show more hydration products than that of raw-40% (raw steel slag mixed with cement as a dosage of 40%) which results in an enhanced compressive strength that could be guaranteed by the dosage of 20% (3 d), 30% (28 d) and 40% (60 d) under the condition of 3 mu m steel slag incorporation with lower autogenous shrinkage. Hemicarboaluminate peak was found in wet-grinding specimens that show a higher calcium sulphoaluminate to calcium. The wet-grinding steel slag CO2 emission and cost showed a downward trend compared with cement.Web of Science286art. no. 12282

A comparative study on concrete slurry waste: performance optimization from the wet-milling process

Concrete slurry waste (CSW) is a mixture of fine aggregates, cement hydration products and residual cement particles obtained from the sedimentation pits during the production of concrete. In the present study, CSW with different grinding durations were evaluated; the properties of the CSW and the CSW-cement composition were compared under the influence of wet-milling. The results indicated that the particle size of the CSW decreased and the dispersion stability of the slurry was improved after wet-milling treatment. The increasing ettringite peak suggested that the mineral admixture hydrated during wet-milling. However, carbonization also occurred during the process. The nucleus effect of wet-milled CSW not only increased the hydration heat and compressive strength of cement, but also significantly enhanced the pore structure and chloride penetration resistance of the mixtures. Although the gel pore volume fraction for the mixture containing original CSW is higher than that of the reference mixtures, the compressive strength and chloride penetration resistance are weak due to the loose structure caused by the dilution effect.Web of Science545art. no. 18

The effect of ultrahigh volume ultrafine blast furnace slag on the properties of cement pastes

The dosage of blast furnace slag (BFS) in cement is limited on account of relative low reaction rate and low early strength. Improving the early age activity of BFS is the fundamental solution for high volume BFS cementitious materials. Generally, mechanical activation is one of the main techniques to accelerate the early reaction of mineral admixtures. In this study, wet-milling and dry-separation are respectively used to prepare ultrafine BFS to improve its early reactivity. The early hydration characteristics, mechanical property, hydration products of ultrahigh volume BFS cementitious materials are analyzed to assess the efficiency of ultrafine BFS on the properties of BFS cement paste. The results show that the initial and final setting time both gradually decrease as the dry-separation BFS (GS) dosage increases, while the wet milling BFS (WS) series present the opposite tendency. The electrical resistivity of WS specimens develops at a faster rate than that of GS specimens. Mixes containing WS, at a maximum dosage of 90%, have higher mechanical property than those with GS, resulting in an enhancement of strength. The hydration products mainly include calcium hydroxide, hydrotalcite, hydrotalcite-like phase, calcium carbonate, stratlingite, C-S-H, C-A-S-H, and akermanite.Web of Science18944743

Dicalcium Silicate Induced Proinflammatory Responses through TLR2-Mediated NF-κB and JNK Pathways in the Murine RAW 264.7 Macrophage Cell Line

Proinflammatory responses are important aspects of the immune response to biomaterials, which may cause peri-implantitis and implant shedding. The purpose of this study was to test the cytotoxicity and proinflammatory effects of dicalcium silicate particles on RAW 264.7 macrophages and to investigate the proinflammatory response mechanism induced by C2S and tricalcium phosphate (TCP). C2S and TCP particles were characterized using scanning electron microscopy (SEM), energy spectrum analysis (EDS) and X-ray diffraction (XRD). Cytotoxicity and apoptosis assays with C2S and TCP in the murine RAW 264.7 cell line were tested using the cell counting kit-8 (CCK-8) assay and flow cytometry (FCM). The detection results showed that C2S and TCP particles had no obvious toxicity in RAW 264.7 cells and did not cause obvious apoptosis, although they both caused an oxidative stress response by producing ROS when the concentrations were at 100 μg/mL. C2S particles are likely to induce a proinflammatory response by inducing high TLR2, TNF-α mRNA, TNF-α proinflammatory cytokine, p-IκB, and p-JNK1 + JNK2 + JNK3 expression levels. When we added siRNA-TLR2-1, a significant reduction was observed. These findings support the theory that C2S particles induce proinflammatory responses through the TLR2-mediated NF-κB and JNK pathways in the murine RAW 264.7 macrophage cell line