In this paper, the effects of dry density, w/c ratio, and municipal solid waste incineration (MSWI) powder on the multi-scale properties and internal pore structure of foamed concrete were studied by using a single-factor controlled experiment. It was found that an increase in the dry density of foamed concrete could effectively reduce the porosity, leading to the improvement of compressive strength and impermeability and to the reduction of water absorption. The compressive strength, water absorption, and impermeability were mainly affected by the porosity when the w/c ratio changed. With the increase in porosity, the water absorption rate increased, and the compressive strength and impermeability decreased. The addition of MSWI powder caused no obvious change in the overall pore size distribution of the foamed concrete, and there was no significant change in the water absorption and impermeability of the structure. However, because the hydration activity of MSWI powder was lower than that of ordinary Portland cement, the compressive strength of foamed concrete decreased with the increase in MSWI powder. Foamed concrete is a new type of porous building material formed by pouring and curing a mixture of cementitious material and prefabricated foam through physical foaming or chemical foaming . Foamed 3. The results indicated that the pore structure, w/c ratio, and admixture had an important influence on the evaluation of the basic performance of foamed concrete.As the advantages of foamed concrete gradually appear, many scholars at home and abroad have carried out relevant research on foamed concrete. The study by Nambiar, E. K. et al.  showed tMunicipal solid waste incineration (MSWI) powder is a byproduct of waste incineration that reduces both the volume and mass to less than 20% of those of the original waste. With the consideration of environmental protection and energy savings, MSWI powder has been paid more and more attention in the civil engineering field. Mathews, G. et al.  tested tAccording to the above discussion, there have been many studies on MSWI powder at home and abroad, but there are still limitations in the activation of MSWI powder, especially in the preparation of foamed concrete with MSWI powder instead of cement. Therefore, MSWI was ground into powder and added into foamed concrete to study its influence on compressive strength, water absorption, impermeability, and pore structure. Combined with the macro performance test indicators and pore structure parameters, the mechanism of MSWI powder in the internal structure of foamed concrete is discussed through experimental research and mathematical analysis.2 was selected as the material for use in this study. Portland cement with a strength grade of 42.5 was used, which conformed to the Chinese GB175-2007 standard [The MSWI powder used in this study was obtained from the Xuyi Household Waste Incineration Power Plant of the Jiangsu Shengyuan Environmental Protection Electric Power Company . The basic physical properties and chemical composition are shown in standard . The AESAccording to the requirements in , the mixVarious materials were weighed according to the mixing ratios shown in ρ0 is the dry density of the test block in kg/m3; m0 is the mass of the test block after drying in g; V is the volume of the specimen in mm3.The determination of the dry density in foamed concrete according to Chinese standard JG/T266-2011 . First, 0.3 to C1 and the pressurization rate was set to 1 kN/s. The compressive strength was calculated according to Equation (2). The compressive strength of an experimental group was the average value of the compressive strengths of three consecutive test blocks in that group.σ is the compressive strength of the test block in MPa; F is the maximum failure load of the test block in N; A is the compression area of the specimen in mm2.The strength of the foamed concrete was tested with a pressure testing machine. After the cubic foamed concrete test block was cured for the required time, it was put into a drying box to dry. In accordance with the same steps as those in the dry density test, the dimensions of the compression test pieces were measured to calculate the compression surface area of the foamed concrete cubes. According to the steps given in the specification , the expw is the water absorption rate in %; m0 is mass of specimen after drying in g; gm is the mass of the specimen after water absorption in g.A group of three specimens were dried in a drying oven, then removed and placed indoors in a dry, shaded area to cool . After tAccording to the existing test methods and specifications ,23, the m0 is the mass of the test block after drying in kg; Sρ is the density of the foamed concrete’s base material, kg/m3; V is the volume of the foamed concrete test block (0.001 m3).According to the Chinese standard GB55008-2021, the porosity of the foamed concrete containing MSWI powder was determined with the direct mass–volume calculation method. The porosity of the foamed concrete was the percentage of the volume of pores with respect to the total volume of the foamed concrete, which directly reflected its overall compactness. The calculation is shown in Equation (4).A hacksaw was used to cut the foamed concrete test block, a relatively flat foamed concrete test block section was selected, and a brush was used to clean the section to make the section’s pores clear. The section of foamed concrete was filmed with a high-definition camera, and data on the pore parameters, such as the pore shape factor and average pore diameter, were collected after bidirectional processing, as shown in In order to study the change in the pore structure in more detail, quantitative parametric data on the pore structure of the foamed concrete samples containing MSWI powder were collected by software. The diameter of a single irregular pore was represented by the average of the interval between the two ends of the pore centroid, as shown in S is the degree of stomata deviating from the circle. When S = 1, the shape of the stomata in a two-dimensional plane is that of a regular circle; the larger the value of S is, the more it deviates from a regular circle; C is the circumference of the projection of the pores onto a two-dimensional plane in mm; A is the area projected by the stomata onto a two-dimensional plane in mm2.The pore shape factor was a parameter used to show the degree of pore deformation. The data collected in this paper were the pore shape factor  in a two-dimensional plane. Equation (5) was used for the calculation; the average pore shape factor was the arithmetic average of all pore shape factors collected in this section.3, the compressive strength of foamed concrete containing MSWI powder was the lowest, and the compressive strength was 0.322 MPa. When the dry density was 600 kg/m3, the compressive strength of foamed concrete containing MSWI powder was the highest, and the compressive strength was 1.394 MPa, increasing by 332.92%. The compressive strength of foamed concrete decreased with the addition content of MSWI powder. When the dry densities of foamed concrete containing MSWI powder were 300, 400, 500, and 600 kg/m3, the compressive strength decreased by 22%, 21%, 19%, and 17%, respectively. The range of the decrease in compressive strength of foamed concrete with MSWI powder decreased with the increase in dry density.The results of the compressive strength tests on the foamed concrete with different densities are shown in A foamed concrete test block containing MSWI powder with a low dry density was prepared with a large amount of prefabricated foam, which was formed at a slower speed and increased the probability of foam damage in the paste. The compactness of the foamed concrete test block with MSWI powder after forming was low, and there were a large number of pores leading through the block and large pores, leading to a low compressive strength. As the dry density of the foamed concrete with MSWI powder increased, the foam content decreased during the preparation and the amount of cementitious material in the foamed concrete with MSWI powder increased, meaning that it could produce more hydration products. The foamed concrete test block with MSWI powder had a faster setting speed, higher early strength, and lower probability of foam damage in the paste. As a result, the structure of the foamed concrete with MSWI powder had a higher compactness, and the compressive strength was improved. The reason for why the compressive strength decreased was that the activity of the MSWI powder was not high and the pozzolanic effect was weak, leading to a decline in the compressive strength of recycled foamed concrete with MSWI powder .3, the compressive strength of the foamed concrete containing MSWI powder first increased and then decreased with the increase in the w/c ratio. When the w/c ratio of the foamed concrete with MSWI powder was 0.5, its compressive strength reached the maximum value. Compared with ordinary foamed concrete, the compressive strength of the foamed concrete with MSWI powder could be reduced by adding MSWI powder. When the dry density of the foamed concrete with MSWI powder was 600 kg/m3 and the w/c ratio was 0.55, its compressive strength was not different from that of traditional, ordinary concrete.When the w/c ratio of the foamed concrete with MSWI powder was small, there was not enough free water in the paste, and the paste could only absorb the water required for the hydration reaction during the initial setting process. The loss of water and the rupture led to an increase in the number of large-sized pores in the structure, and the reduction of the compactness of the paste structure reduced the compressive strength. When the w/c ratio increased, the fluidity of the paste increased and the friction between the foam and the material decreased, making the foam difficult to burst. The foamed concrete specimens with MSWI powder became denser and their compressive strength increased after solidification and hardening. When the w/c ratio exceeded 0.50, in the curing process of the foamed concrete with MSWI powder, the phenomenon of the bleeding of paste began to occur, and the excess free water in the paste absorbed the heat generated by the hydration reaction and evaporated, leaving a large number of capillary pores and cracks .3 and the w/c ratio increased from 0.4 to 0.55, the compressive strength of the foamed concrete with MSWI powder increased with the increasing w/c ratio because the particle size of the MSWI powder was smaller than that of cement. When replacing equal-quality cements, more cementitious materials could be introduced, while the MSWI powder had a morphological effect, which could make the paste uniform. The MSWI powder had a micro-aggregate effect and an effect on the activity [The internal structural compactness of the degraded foamed concrete decreased, resulting in a decline in compressive strength. When the dry density was 600 kg/mactivity ,27. When3 was less than 0.225 MPa, which did not meet the requirements of the specification [The results of the compressive strength test on the foamed concrete with different MSWI powder contents at a w/c ratio of 0.5 are shown in fication .When the density of the foamed concrete with MSWI powder was low, there was less cementing material in the paste, and the amount of foam was greater. With the increase in MSWI powder content, the proportion of cement in the cementing material decreased, and the strength of the foamed concrete decreased due to hydration products. At the same time, the ultra-fine MSWI powder made after crushing and grinding had certain activated ingredients, but the overall activity was not high and the early pozzolanic effect was weak, leading to a decline in the compressive strength of the foamed concrete with MSWI powder. In addition, when the content of MSWI powder increased to a certain extent, although it had a morphological effect and could make the paste more uniform, the reduction in hydration products caused the foamed concrete with MSWI powder to be unable to completely wrap the foam in the hardening process. The probability of the foam bursting in the concrete structure became higher, and more pores going through the structure were formed .The inte3, the water absorption of the sample was the highest, and the value was 42.55%. When the dry density was increased to 600 kg/m3, the water absorption rate was the lowest, and the value was 23.79%. The decrease in the water absorption of the foamed concrete with MSWI powder decreased with the increase in dry density. When the dry density of the foamed concrete with MSWI powder was 300, 400, 500, and 600 kg/m3, respectively, the water absorption rate of the foamed concrete with MSWI powder decreased by 2.01%, 3.01%, 4.02%, and 7.02%. Through a comparison with ordinary foamed concrete, MSWI powder was found to reduce water absorption, but the effect was limited. On the one hand, the foamed concrete containing MSWI powder with a low density had many internal pores, and there were a large number of connecting pores and large pores, which increased the water absorption. With the increase in dry density, the number of through-pores in the foamed concrete and, especially, the number of large pores decreased, resulting in a decrease in water absorption. On the other hand, when preparing the foamed concrete test blocks with a low dry density, the amount of foam increased, resulting in more free water being introduced by the foam. The decrease in the amount of cementitious material caused the foamed concrete to bleed water in the hardening process, leading to a reduction in the structural compactness and even the paste stratification of the foamed concrete, causing a large number of connected pores to be formed and increasing the water absorption rate [ion rate .3, the foamed concrete with MSWI powder had the best impermeability, and the penetration time was 1.25 h. The MSWI powder could effectively improve the impermeability of the foamed concrete. When the dry densities were 300, 400, 500, and 600 kg/m3, the impermeability increased by about 16.7%, 12.7%, 18.1%, and 14.7%. Under the condition of a constant w/c ratio, foamed concrete containing MSWI powder with a low dry density was prepared by adding a large number of prefabricated foams; the reduction of gelled particles led to a slow hydration reaction in the early stage, and the foam in the paste was easy to burst. However, there were more pores in the test block, and the overall density of the structure was low. Under the action of external pressure, water could enter the interior of foamed concrete along the through-pores, resulting in poor impermeability [eability .3 and the MSWI powder content was 10%. With the increase in the w/c ratio, the infiltration time of the foamed concrete containing MSWI powder showed a trend of first extending and then shortening. When the w/c ratio was 0.4, the permeability time was 0.52 h, which was the shortest permeability time and the worst permeability performance. When the w/c ratio was 0.5, the infiltration time was 0.77 h, the infiltration time was the longest, and the anti-permeability performance was the best. When the w/c ratio was more than 0.5, the penetration time was shortened and the anti-permeability decreased. Compared with ordinary foamed concrete, the addition of MSWI powder could slightly improve the impermeability of the recycled foamed concrete. When the w/c ratio was 0.4–0.55, the impermeability increased by 6%, 13.8%, 18.1%, and 20%, respectively.3 and the MSWI powder content was 10%, the impermeability of the recycled foamed concrete was the best, and the permeation time was 1.25 h. The addition of MSWI powder could improve the impermeability of the foamed concrete. The MSWI powder had a good morphological effect, which could improve the fluidity of the foamed concrete and prevent the separation of fresh paste and rupturing of the foam. Secondly, the MSWI powder resulted in hydration activity, which could accelerate the hydration reaction in the cement and prevent foam deformation and rupture. Finally, the particle size of the MSWI powder was smaller than that of cement, and it could fill through-pores and cracks in the foamed concrete, thus playing a role in regulating pores. However, due to the limited activity and the delay of the MSWI powder, the improvement of the anti-seepage performance was limited. With the further increase in MSWI powder content, the proportion of cement in the foamed concrete paste decreased, and the production of hydration products decreased, leading to the deterioration of the internal structure and a decrease in the compactness. Under the action of external pressure, water was more likely to enter the recycled foamed concrete test block, resulting in poor impermeability [The results of the impermeability test of the foamed concrete containing MSWI powder with different contents are shown in eability .3, the porosity of the foamed concrete was 77.98%. When the dry density was 600 kg/m3, the porosity of the foamed concrete was the lowest, which was 56.65%, decreasing by 21.33%. The porosity of the foamed concrete decreased with the addition of MSWI powder. When the dry density was 300, 400, 500, and 600 kg/m3, the porosity decreased by about 1.17%, 2.16%, 2.85%, and 3.12%. As can be seen from 3, the average pore diameter was 0.398 mm. However, when the dry density of the MSWI powder foams was increased to 600 kg/m3, the average pore size was 0.259 mm, which was a decrease of about 34.9%. It can be seen in The pore structures of the foamed concrete containing MSWI powder with different w/c ratios are shown in 3 and MSWI powder content of 10%, with the increase in the w/c ratio, the pores of the foamed concrete containing MSWI powder first decreased and then increased. When the w/c ratio was 0.4, the internal porosity of the foamed concrete containing MSWI powder was the highest, which was 71.35%. When the w/c ratio was 0.5, the porosity of the foamed concrete containing MSWI powder was the lowest, which was 60.44%, decreasing by about 10.91%. As can be seen in 3 and the MSWI powder content was 10%, the average pore size of the foamed concrete containing MSWI powder first decreased and then increased, but the range of variation was different. When the w/c ratio was 0.5, the average pore size of the foamed concrete containing MSWI powder was the smallest (0.327 mm), which was decrease of about 7.7% compared with that when the w/c ratio was 0.4. Through a comparison with ordinary foamed concrete, the addition of MSWI powder was shown to adjust the pore structure of the foamed concrete and reduce the average pore size inside it. As can be seen in As can be seen in 3 and the w/c ratio was 0.5, the pore size distribution range of the foamed concrete containing MSWI powder first decreased and then expanded with the increase in MSWI powder content. These results showed that the number of small-size pores formed in the foamed concrete first increased and then decreased, while the number of large-size pores first decreased and then increased. When the MSWI powder content was 10%, the pore size distribution range was the smallest, and the number of pores in the range of 0–0.4 mm accounted for 90.3% of the total number of pores collected. It can be seen in As can be seen in The addition of MSWI powder was able to adjust the internal pore structure of the foamed concrete. Because the MSWI powder had a good morphological effect that could prevent the stratified segregation of the freshly mixed paste and the deformation and rupture of the internal foam, the degree of deformation of the pores was reduced. Secondly, the MSWI powder resulted in hydration activity, and the effect of the activity could generate more hydration products, which accelerated the hydration reaction in the cement and optimized the internal pore structure of the foamed concrete. The particle size of the MSWI powder was smaller than that of the cement. The MSWI powder that had not undergone a hydration reaction after being mixed into the foamed concrete could fill the pores inside it. This made the interior of the foamed concrete structure denser, and the porosity and the size of the pores were reduced. However, due to the low activity and retardation of the MSWI powder, the effect of the adjustment of the cellular structure of the foamed concrete was limited. The addition of MSWI powder at a low dosage reduced the proportion of cement in the cementitious material, reducing the heat of hydration released during curing. The evaporation of free water inside the paste was reduced, and the probability of the formation of large-sized pores and through-holes was reduced. When the content of the MSWI micropowder was higher, the proportion of cement in the foamed concrete paste decreased, and the generation of hydration products decreased. The deterioration of the internal structure of the foamed concrete resulted in an increase in the porosity of the foamed concrete and an increase in the internal large-sized pores ,38.−0.1238x + 0.26244, which was an exponential function relationship, and the correlation coefficient was R2 = 0.993. It can be seen in 2 reached 0.997. By comparing the results of the above analysis, it can be seen that, when only the dry density changed, the compressive strength of the foamed concrete containing MSWI powder was mainly affected by the average pore size of the pores in it. This was because, with the increase in dry density, the number of pores in the foamed concrete containing MSWI powder decreased, especially the number of large pores. The rapid reduction of the average pore size of the internal pores of the foamed concrete containing MSWI powder made the structural compactness increase continuously, so the compressive strength was significantly improved.3 and the powder content was 10%, the foamed concrete containing MSWI powder with different w/c ratios was analyzed, and the results are shown in 3 and the content of the recycled fine MSWI powder was 10%, with the increase in the porosity of the foamed concrete containing MSWI powder, the compressive strength of the foamed concrete containing MSWI powder decreased. After data fitting, the following relationship between the two was obtained: y = −1.749619 × 10−21 × e0.65856x + 0.9118, showing an exponential relationship, similarly to the Ryshkevitch model [2 = 0.998. As can be seen in 3 and the MSWI powder content was 10%, the compressive strength of the foamed concrete containing MSWI powder decreased with the increase in the average pore size. After data fitting, the following relationship between the two was obtained: y = −5.016 × 10−35 × e220.75x + 0.90735, which was an exponential relationship, and the correlation coefficient was R2 = 0.998. When only the w/c ratio changed, the compressive strength of the foamed concrete containing MSWI powder was significantly affected by the porosity. This was mainly because the porosity of the foamed concrete changed more than the average pore size with the change in the w/c ratio. The numbers of large-sized pores and through-pores in the foamed concrete containing MSWI powder varied greatly, which affected its compactness. The compactness of the foamed concrete containing MSWI powder was directly related to its compressive strength, so there was a more obvious effect on its compressive strength.When the dry density was 500 kg/mch model ; the cor−0.0318x + 62.92733, which was an exponential function, and the correlation coefficient was R2 = 0.999. It can be seen in 15.0921x + 19.4323, which was an exponential function, and the correlation coefficient was R2 = 0.999. When only the dry density changed, the water absorption of the foamed concrete containing MSWI powder was significantly affected by the porosity. This was because the compactness of the foamed concrete containing MSWI powder increased with the increase in dry density, while the porosity of the internal pores changed more obviously compared with the average pore size. With the increase in dry density, the number of large-sized pores and through-pores in the foamed concrete containing MSWI powder decreased remarkably. The water absorption rate could directly reflect the proportion of through-pores in all pores in the foamed concrete containing MSWI powder. The larger the proportion of through-pores, the higher the water absorption rate of the foamed concrete containing MSWI powder. Therefore, the water absorption of the recycled foamed concrete containing MSWI powder was obviously affected by its porosity.−4e0.1261x + 26.2701, which was an exponential function; the increase was from slow to fast, and the correlation coefficient was R2 = 0.998. When the porosity was greater than 68%, the water absorption rate rapidly increased with the increase in the porosity. At this time, most of the pores in the foamed concrete were through-pores, and the increase in the proportion of through-pores led to an increase in the water absorption rate. It can be seen in 3, the content of MSWI powder was 10%, and only the w/c ratio changed. With the increase in the average pore size of the foamed concrete containing MSWI powder, its water absorption increased linearly, and the rate of increase was relatively stable. At this time, the relationship between the average pore size and water absorption was y = 100.2899x − 5.57326, and the correlation coefficient was R2 = 0.993. By comparing the results of the above analysis, it can be seen that, when only the w/c ratio changed, the water absorption of the foamed concrete containing MSWI powder was significantly affected by the porosity. With the change in the w/c ratio, the porosity of the foamed concrete containing MSWI powder changed more obviously than the average pore size, and the number of large-sized pores and through-pores in the foamed concrete containing MSWI powder changed greatly. The water absorption rate could directly reflect the proportion of through-pores to all pores in the foamed concrete containing MSWI powder. The larger the proportion of through-hole pores, the higher the water absorption rate. Therefore, the water absorption of the foamed concrete containing MSWI powder was affected more by porosity.−0.1503x + 0.453, which was an exponential function, and the correlation coefficient was R2 = 0.999. It can be seen in 2 = 0.998. By comparing the results of the above analysis, it can be seen that, when only the dry density changed, the impermeability of the foamed concrete containing MSWI powder was significantly affected by the porosity. With the increase in dry density, the compactness of the recycled foamed concrete containing MSWI powder increased continuously, while the porosity of the internal pores changed more than the average pore size. With the increase in dry density, the numbers of large-sized pores and through-pores in the foamed concrete containing MSWI powder were greatly reduced. The impermeability of the foamed concrete containing MSWI powder was related to the proportion of internal through-pores. The lower the proportion of through-pores, the better the impermeability of the foamed concrete containing MSWI powder. Therefore, the impermeability of the foamed concrete containing MSWI powder was obviously affected by the porosity.0.07718x + 1.3097), and the correlation coefficient was R2 = 0.980. It can be seen in 3, the content of fine MSWI powder was 10%, and only the w/c ratio changed, the impermeability became worse with the increase in the average pore size of the foamed concrete. After fitting, the relationship between the two was y = −11.9565x + 4.9583, which was linearly correlated, and the correlation coefficient was R2 = 0.998. By comparing the results of the above analysis, it can be seen that when only the w/c ratio changed, the impermeability of the foamed concrete containing MSWI powder was mainly affected by the porosity. With the change in the w/c ratio, the porosity of the recycled foamed concrete containing MSWI powder changed more obviously than the average pore size, and the number of large-sized pores and through-pores in the foamed concrete containing MSWI powder changed significantly. The impermeability of the foamed concrete containing MSWI powder was related to the proportion of internal through-holes. The lower the proportion of through-holes, the better the impermeability of the foamed concrete containing MSWI powder. Therefore, the impermeability of the recycled foamed concrete containing MSWI powder was obviously affected by the porosity.(1)3, the compressive strength of the foamed concrete increased with the increase in the w/c ratio, and the optimal MSWI powder content was 10%.The compressive strength of the foamed concrete containing MSWI powder increased with the increase in dry density, while the compressive strength first increased and then decreased when the w/c ratio increased. The hydration activity of the MSWI powder was low, and the incorporation of MSWI powder reduced the proportion of cement in the foamed concrete slurry, thus reducing the amounts of hydration products. During the hardening process, the probability of foam bursting increased, resulting in the formation of more through-pores and the reduction of compressive strength. When the MSWI powder content was 10% and the dry density was 600 kg/m(2)3 and the MSWI powder content was 10%, the impermeability of the foamed concrete with a w/c ratio of 0.5 was the best. The MSWI powder had an active effect and a micro-aggregate effect, which could effectively fill capillaries and through-pores and optimize the internal pore structure of the foamed concrete, thus improving its impermeability.With the increase in dry density, the water absorption rate decreased, the infiltration time was prolonged, and the impermeability was improved. The water absorption of the foamed concrete first increased and then decreased with an increasing w/c ratio. When the dry density was 500 kg/m(3)With the increase in dry density, the porosity and average pore shape coefficient of the foamed concrete decreased. The characteristic parameters of the pores first decreased and then increased with the increase in the w/c ratio. With the increase in the MSWI powder content, the average pore size of the foamed concrete first decreased and then increased, the average pore size and shape factor decreased, and the porosity changed a little, indicating that the MSWI powder had a limited role in regulating the pores, and the internal structure deteriorated when the content of MSWI powder was higher.(4)When the dry density and w/c ratio changed, the pore structural parameters had a significant effect on the compressive strength, water absorption, and impermeability. The compressive strength of the foamed concrete decreased with the increase in the average pore size, the water absorption increased with the increase in porosity, and the impermeability decreased with the decrease in compressive strength.In this paper, the effects of the dry density, water–cement ratio, and MSWI powder content on the performance and pore structure of foamed concrete containing MSWI powder were studied with a single-factor mix ratio test, and the following conclusions were obtained:


Fuzi is commonly used in traditional Chinese medicine. Clinical Fuzi poisoning cases have frequently been reported. Glycyrrhizae Radix is often used to alleviate Fuzi's toxicity. However, the poisoning mechanism of Fuzi and the detoxication mechanism of Glycyrrhizae Radix are still not clear. We identified the chemical components of Fuzi at different decoction times  using ultrahigh performance liquid chromatography quadrupole time-of-flight mass spectrometry. A total of 35 compounds were detected in the Fuzi decoction, including diester alkaloids, monoester alkaloids, amino acids, phenolic acids, organic acids, glycosides, and sugars among others. The content of diester alkaloids  in the Fuzi decoction decreased after 2 h of decoction time, while the content of monoester alkaloids  reached a peak at 2 h. A total of 32 rats were randomly divided into four groups, including 8 cases in the low-dosage Fuzi decoction group A, 8 cases in the high-dosage Fuzi decoction group B, 8 cases in the Fuzi and glycyrrhizae decoction group C, and 8 cases in the control group D. The decoction was administered orally for 7 days. Then, a serum was obtained. The metabolites' changes were analyzed in serum metabolomics using liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Statistical analysis and pathway analysis were used to assess the effects of glycyrrhizae on the metabolic changes induced by Fuzi. The behavioral and biochemical characteristics indicated that Fuzi exhibited toxic effects on rats and their metabolic profiles changed. However, the metabolic profiles of the glycyrrhizae group became similar to those of the control group. These profiles showed that glycyrrhizae can effectively improve Fuzi poisoning rats. Our study demonstrated that the established pseudotargeted metabolomics is a powerful approach for investigating the mechanisms of herbal toxicity. Aconitum carmichaelii  has positive pharmacological effects on various diseases such as painful joints, collapse, rheumatic fever, bronchial asthma, syncope, edema, various tumors, and diarrhea [Materia Medica. However, its medicinal application on a large scope was limited due to the high toxicity risk and narrow therapeutic range [Traditional Chinese medicine is generally considered natural and harmless –3. Aconidiarrhea –6. Fuzi ic range . It is iic range –10. TherA clear understanding of the mechanism of Fuzi at the selected decoction time is essential to evaluate its safety. Metabolomics is a comprehensive method for diagnosing diseases, discovering biomarkers, and identifying perturbed pathways –14. Sui First, nontargeted serum metabolites were used in full scan and data-dependent modes to generate as high of coverage serum metabolite profiling as possible. Secondly, serum metabolite ion pairs were constructed based on the characteristic fragmental ions and corresponding parent ions of the serum metabolites, which were monitored in an MRM mode in the pseudotargeted metabolomics method. This method combines the advantages of nontargeted and targeted metabolomic approaches.In a previous study, Luo et al. displayed the dynamic variation patterns of the Aconitum alkaloids in Fuzi during the decoction process . HoweverIn our study, we explored the relationship between the chemical components of Fuzi with the decoction time to identify the appropriate decoction time using ultrahigh performance liquid chromatography quadrupole time-of-flight mass spectrometry (UPLC-QTOF). Pseudotargeted rat serum metabolomics was used to evaluate the toxic mechanism of Fuzi and the detoxification mechanism of Glycyrrhizae Radix. This study was the first time where Fuzi poisoning was systematically interpreted, thus providing some information for the future clinical use of Fuzi.HPLC-grade acetonitrile (purity: 99.9%) was supplied by Fisher Scientific . Water was obtained from Watsons. HPLC-grade formic acid (purity: 98%), chloramphenicol (purity: 98%), and clenbuterol (purity: 98%) were purchased from Sigma-Aldrich . Fuzi and Glycyrrhizae Radix were obtained from the Hospital of Traditional Chinese Medicine of Zhongshan  and authenticated by Director Wu from the same hospital.Fuzi (60 g) was immersed in 200 mL water for 30 min and was then boiled for 0.5, 1, 2, 4, and 6 h, respectively. The supernatant was collected by filtration and centrifuged for 15 min at 4000 g. It was then concentrated to a final volume of 20 mL. The preparation of the Glycyrrhizae Radix decoction was the same as that for Fuzi. Glycyrrhizae decoction containing 3 g raw material per mL was obtained.n = 8/group) as follows: oral gavage with Fuzi at a dose of 30 g/kg (group A), oral gavage with Fuzi at a dose of 60 g/kg (group B), oral gavage with Fuzi and glycyrrhizae at a dose of 60 g/kg (group C), and oral gavage of the same volume of water to healthy controls (group D) as the other three groups. All the groups were given intragastric administrations twice a day for 7 days.Thirty-two male Wistar rats (180–220 g) were supplied by the Southern Medical University Laboratory Animal Center and were allowed to acclimatize in cages for 1 week before the experiment. The rats were randomly divided into four groups  using a SCIEX ExionLC AD UPLC system . The column temperature was maintained at 40°C, and the mobile phase consisted of 0.1% formic acid in water (Phase A) and acetonitrile (Phase B) at a constant flow rate of 0.3 mL/min. The injection volume was 5 μL. The 45 min binary gradient elution conditions were optimized as follows: linear gradient from 5% to 10% B (0.5–5 min), 10% to 95% B (5–35 min), 95% to 5% B (40-40.1 min), and then the column was returned to its starting conditions of 5% B for 5 min to allow for column re-equilibration. SCIEX X500R QTOF mass spectrometry  was used to analyze the components of the Fuzi decoction. The optimized MS conditions were as follows: TOF MS scan range: m/z 70–1500; TOF MS/MS scan range: m/z 50–1500; curtain gas: 35 psi; nebulizer gas: 55 psi; heater gas: 50 psi; temperature: 550°C; ion spray voltage: 5500 V (positive mode)/−4500 V (negative mode); declustering potential: 100 V (positive mode)/−100 V (negative mode); collision potential: 40 ± 20 eV (positive mode)/−40 ± 20 eV (negative mode). A typical information-dependent acquisition (IDA) process was used to carry out the MS/MS experiment.Chromatography separation of Fuzi decoction was performed on a Waters T3 column  using a SCIEX ExionLC AD UPLC system . The column temperature was maintained at 40°C, and the mobile phase consisted of 0.1% formic acid in water (Phase A) and acetonitrile (Phase B) at a constant flow rate of 0.4 mL/min. The injection volume was 10 μL. The 11 min binary gradient elution conditions were optimized as follows: linear gradient from 5% to 95% B (1–7 min), 95% to 5% B (9.5-9.6 min), and then the column was returned to its starting conditions of 5% B for 1.5 min to allow for column re-equilibration. SCIEX 4000 QTrap mass spectrometry  was used to detect the metabolites of serum samples. The optimized MS conditions were as follows: curtain gas: 35 psi; nebulizer gas: 55 psi; heater gas: 50 psi; temperature: 550°C; ion spray voltage: 5500 V (positive mode)/−4500 V (negative mode). The MRM transitions of 166 metabolites are shown in the Supplementary Materials (MRMs), which include the metabolite name, their parent ions . Multivariate statistical analysis was performed on MetaboAnalyst 4.0 . Partial least-squares discriminant analysis (PLS-DA) was used to model all features of the four groups. All the metabolites with a significance threshold that satisfies the corrected m/z 646.3233 (tR = 20.72 min) as an example to be described as follows. Its molecular formula was speculated to be C34H47NO11 based on its parent ion and isotope abundance. In the positive mode, its product ions were observed at m/z 586.2994, 554.2753, 368.1859, and 105.0341, which could be obtained by neutral loss of –C2H4O2, –C3H8O3, –C14H32O5, and –C27H43NO10, respectively. Finally, according to the SCIEX Commercialize Traditional Chinese Medicine database, the ion was tentatively identified as aconitine. The fragmentation pattern of aconitine is shown in All components of Fuzi were represented as chromatographic peaks. The parent ions and their product ions were obtained for structural identification. To illustrate the identification of components, we took the The Fuzi decoction times were 0.5, 1, 2, 4, and 6 h, respectively. The content of the components was compared at different decoction times, as can be seen in p < 0.05) in one-way ANOVA were selected. The one-way ANOVA plot is shown in Serum samples were divided into the following four groups: group A (30 g/kg dosage of Fuzi), group B (60 g/kg dosage of Fuzi), group C (60 g/kg dosage of Fuzi and 60 g/kg dosage of glycyrrhizae), and group D (control). The multireaction monitor (MRM) trigger enhanced product ion mode was applied to detect the serum metabolites. Typical serum chromatograms are shown in A simple, efficient, and sensitive method was established to identify the components of Fuzi decoction at different decocting times using the X500R QTOF system. A total of 35 compounds were found, including 3 diester alkaloids, 2 monoester alkaloids, 3 other alkaloids, 3 base compounds, 6 amino acids, 4 phenolic acids, 3 organic acids, 3 glycosides, and 3 sugars. There were also 5 other categories examined . The results showed that the diester alkaloids in Fuzi gradually increased and reached the peak in 1∼2 h and then decreased significantly. The monoester alkaloids also gradually increased and reached the peak at 2 h and then decreased significantly. Diester alkaloids with high toxicity are thermally unstable. They can be transformed into monoester alkaloids and further transformed into other alkaloids. This suggests that Fuzi can effectively reduce toxicity after a decocting time of more than 2 h, thus providing useful information for the clinical use of Fuzi.When used in clinical settings, Fuzi could cause cardiotoxins, neurotoxins, nausea, palpitations, dizziness, vomiting, arrhythmia, hypotension, asystole, shock, coma, and neuron apoptosis among others , 20. AcoIn our study, pseudotargeted metabolomics was used to investigate the effect of glycyrrhizae on Fuzi-induced toxicity. The pseudotargeted method combines nontargeted and targeted analysis, which has proven to be a high-quality and information-rich method . From anIn our study, a total of 35 components in Fuzi were identified using UPLC-QTOF. Pseudotargeted metabolomics was used to detect the effects of glycyrrhizae on Fuzi-induced toxicity in rats. The results showed that amino acids and organic acids were significantly altered by Fuzi administration in rats. Glycyrrhizae could mitigate these metabolic changes, indicating that glycyrrhizae administration could reduce the toxicity of Fuzi at the metabolic level. The toxicity of Fuzi could be reduced at more than 2 h of decoction time. Our results demonstrate that glycyrrhizae reduces toxicity at the metabolic level through a series of pathways, such as linoleic acid metabolism, biosynthesis of unsaturated fatty acids, fatty acid biosynthesis, and citrate cycle.


Chondroitinase ABC (chABC) is an enzyme could improve regeneration and thereby improving functional recovery of spinal cord injury (SCI) in rodent models. Degradation of the active enzyme and diffusion away from the lesion are the causes of using hydrogels as a scaffold to deliver the chABC into the lesion site. In this meta-analysis, we investigated the effects of chABC embedded in a scaffold or hydrogel on the functional recovery after SCI.Databases were searched based on keywords related to chABC and spinal cord injury (SCI). Primary and secondary screening was performed to narrow down study objectives and inclusion criteria, and finally the data were included in the meta-analysis. The standard mean difference of the score of the functional recovery that measured by Basso, Beattie, Bresnahan (BBB) test after SCI was used to analyze the results of the reported studies. Subgroup analysis was performed based on SCI model, severity of SCI, transplantation type, and the follow-up time. Quality control of articles was also specified.The results showed that embedding chABC within the scaffold increased significantly the efficiency of functional recovery after SCI in animal models  in 9 studies. SCI model, severity of SCI, injury location, transplantation type, and the follow-up time did not affect the overall results and in all cases scaffold effect could not be ignored. However, due to the small number of studies, this result is not conclusive and more studies are needed.The results could pave the way for the use of chABC embedded in the scaffold for the treatment of SCI and show that this method of administration is superior to chABC injection alone. Spinal cord injury (SCI) is caused by damage to the spinal cord that causes is associated with temporary or permanent impairment in neurological function , 2. SCI Several experiments have shown that at the site of the lesion, chondroitin sulfate proteoglycans (CSPGs) are secreted in increasing quantities by the stimulated astrocytes and oligodendrocytes. These CSPGs subsequently inhibit the axonal regeneration that might occur after SCI –21. The Chondroitinase ABC (chABC) is an enzyme that can break the sulfated GAG chains on the CSPGs which are a main element of the glial scar –33. DegrOne major issue is that the administration of chABC by injection, by using an intrathecal catheter, or pumping through a cannula cannot guarantee sufficient sustained concentrations of drug at the injury site , 30. MorOne approach to prevent premature degradation of the enzyme and to increase its efficacy is to use a variety of scaffolds that can be loaded with chABC for sustained release , 43, 44.In this meta-analysis, we compared the effects of chABC when loaded inside a scaffold with untreated animals, on functional improvements after SCI in animal models.The guidelines of Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) were used for this study. The review protocol for this study has not been published.Using keyword groups related to chABC and spinal cord injury, listed in Table Duplicate articles were removed and then the two reviewers reviewed the articles separately by reading the titles, abstracts, and complete texts (if the titles and abstracts did not cover necessary information). Disagreements over selection of studies were resolved through discussions between them.Only studies were included for analysis that reported the effect of chABC embedded in any type of scaffold, using in-vivo experiments in animals with SCI, and the result using the BBB test to measure functional recovery was compared with the untreated SCI group.Exclusion criteria were: review articles, articles that did not use chABC embedded in scaffolding as intervention, studies that did not compare the treatment group with the control group.Both assessors independently extracted the following information from the articles: animal features, species, gender, weight, age, sample size, studied organ, duration of exposure, study time, type of transplantation of chABC (implant or injection), chABC concentration, vehicle name and the score of BBB test which represent the functional recovery after SCI. Analysis was performed by calculation of standard mean differences (SMD) of the mean of BBB test and the reported standard deviation for each group. The risk of bias assessment of articles was achieved based on the study of Hassannejad et al. .For data analysis STATA 14.0 statistical software was used. Data as mean and standard deviation were presented. The effect size was calculated with a 95% confidence interval (95% CI). The fixed-effect model was used, and if the heterogeneity was more than 50%, the random-effect model was used. Using Egger’s precision-weighted linear regression method, the existence of publication bias was explored, and the results were available in funnel plots. Significant level in all analyses was considered p < 0.05.1364 articles were initially acquired from a general search of the records. When removing identical articles, 961 articles were carefully chosen based on evaluation of the titles and abstract. After evaluating the full text, 9 articles finally were used for the meta-analysis. Figure 9 studies look at the effect of chABC embedded in a scaffold on animal locomotion after SCI. The data gained from these articles is prepared in Table The calculation of the risk of bias indicated low risk of bias in all articles in the following categories: species, strain, genetic background, age/weight, and number of animals per group, description of control, method of group allocation, objective tissue, use of suitable tests, and description of statistical analysis.2 articles displayed a great risk of bias regarding the blinding of the assessor, 6 articles displayed a high risk of bias regarding randomization, 2 articles displayed a high risk of bias in terms of the definition of the experimental unit, 2 articles showed a high risk of bias in terms of description of the animal facility, 7 articles showed a high risk of bias in term of regulations and ethics, and 8 articles showed a high risk of bias in term of the reasons to exclude animals from the study Table .Table 3BIn the current study, publication bias was observed in 9 studies describing the effects of a scaffold embedded with chABC on the motor function recovery test of animals after SCI p = 0.02) 2 = 86.8%, p < 0.001).The results of the meta-analysis showed that embedding chABC into a scaffold had a significant effect on the recovery of motor function  (Fig. In the subgroup analysis Table , it was In this article, the effect of the chABC enzyme embedded in a scaffold on the treatment of SCI was systematically investigated. The results showed that the chABC embedded in a scaffold could significantly improve the functional recovery compared to untreated animals.Many pre-clinical articles have examined the effects of chABC injection on the improvement of functional recovery after SCI –62. The The results of the present study that analyzed all articles that employed chABC embedded in a hydrogel or a scaffold, showed that its effect on the functional recovery post-SCI was stronger and more significant than chABC alone. Based on the result, none of the factors involved in the SCI model, SCI severity, location of the injury, type of transplant, follow-up time, influenced on the therapeutic effect that according to the small number of studies makes it impossible to accept this result with certainty. Treatment of a damaged spinal cord with chABC is designed to attenuate the inhibitory effects of CSPGs that accumulate in the lesion site, and is expected to improve overall functional recovery. Injection of the free enzyme is the most common method to administer chABC, but the disadvantage of the injection at the lesion site, is that the injected chABC is subject to rapid degradation by the host enzyme and body temperature , 64, andAlthough our analysis was based on 9 articles, and the number of articles could be seen as one of the limitations, nevertheless the results can pave the way for the use of scaffold-embedded chABC to treat SCI and suggests this route of administration is superior to injection of chABC alone.


The public's irrational use of antibiotics for upper respiratory tract infections (URTIs) is prevalent worldwide. This study aims to synthesize evidence on how people use antibiotics to treat URTIs, its prevalence and determinants.A mixed methods systematic review was conducted using a convergent segregated approach. Relevant studies were searched from PubMed, Cochrane Library, Embase, and Web of Science. A qualitative analysis was initiated, exploring the public's antibiotic use experience for URTIS based on the Consumer Behavior Model (CBM). This was followed by a quantitative synthesis, tapping into the prevalence and predictors of public behavior in antibiotic usage for URTIs. The segregated syntheses complemented each other and were further integrated.n = 29), Asia (n = 27) and North America (n = 21), assessing the behaviors of patients (n = 46), their parents or caregivers (n = 31), or both (n = 9). Eleven themes emerged covering the six CBM stages: need recognition, information searching, alternative evaluation, antibiotic obtaining, antibiotic consumption, and post-consumption evaluation. The six stages reinforce each other, forming a vicious cycle. The high prevalence of the public's irrational use of antibiotics for URTIs is evident despite the high heterogeneity of the studies (ranging from 0.0 to 92.7%). The perceived seriousness of illness and misbelief in antibiotics were identified consistently across the studies as the major motivation driving the public's irrational use of antibiotics for URTIs. However, individual capacity  and opportunity  in reducing antibiotic use have mixed effect.A total of 86 studies were included: 48 quantitative, 30 qualitative, eight mixed methods studies. The included studies were conducted in Europe (Systemic interventions concerning both supply and demand sides are warranted. The public needs to be educated about the appropriate management of URTIs and health care providers need to re-shape public attitudes toward antibiotic use for URTIs through communication and prescribing practices.https://www.crd.york.ac.uk/prospero, identifier: CRD42021266407. Antibiotic resistance (AR) is one of the most concerning threats to public health and economic development recognized by people all over the world –3. WithoThe general public plays an important role in the control of antibiotic use . ExistinExtensive studies have been conducted to explore the knowledge, attitudes and behaviors of the public in relation to antibiotic consumption under various socioeconomic circumstances , 16–19. URTIs are the predominant condition that contributes to the irrational use of antibiotics. Given that most URTIs are minor and self-limiting, it is desirable to reduce unnecessary care-seeking for URTIs , 24. HowThis mixed methods systematic review responds to the aforementioned call, aiming at answering the following questions: (1) How do people decide to use or not to use antibiotics for URTIs? (2) How prevalent is the irrational use of antibiotics for URTIs and which factors contribute to the decision of consumers in regard to the use of antibiotics for URTIs?A mixed methods systematic review was conducted with a convergent segregated approach following the Joanna Briggs Institute (JBI) guidelines . The decThis systematic review was pre-registered in PROSPERO (No. CRD42021266407). It forms part of a large research project in China, the protocol of which has been published elsewhere .Relevant publications were searched from PubMed, Cochrane Library, Embase and Web of Science from inception to 28 October 2021. The search strategy considered the Participant, Intervention, Comparison, Outcomes (PICOs) principle, using a combination of key terms associated with “user/public,” “respiratory infection,” “antibiotic/antimicrobial,” and “behavior.” Details of the search syntax were included in the An additional manual search was conducted through the references cited by the identified studies.Eligible studies were those peer-reviewed original research studies published in the English language. Studies that (1) were commentary and reviews, (2) were written in a language other than English, (3) did not involve antibiotic use, (4) focused only on healthcare providers, and (5) did not specify URTIs were excluded. A full list of the inclusion/exclusion criteria is presented in the Two researchers (CL and LD) screened the titles and abstracts of the retrieved studies against the inclusion and exclusion criteria independently. Full texts of those deemed relevant (including those disputed by the two reviewers) were extracted and further scrutinized by the same two reviewers (CL and LD) independently. Any discrepancy was resolved through discussions involving a third researcher (DW).The risk of bias of the included studies was assessed using the JBI checklist for quantitative studies , the CriData on the eligible studies were extracted into an Excel spreadsheet, covering the characteristics of study participants, methodological design and the main findings of the studies. Two reviewers (CL and LD) mapped and coded the original data into the pre-established theoretical framework . Any disA theory-driven thematic analysis was performed on the qualitative studies and the qualitative components of the mixed method studies. The decision-making process of the public regarding antibiotic use for URTIs was classified into six steps according to the CBM:Need recognition: perceptions of the nature and seriousness of URTIs;Information searching: information acquirement about URTI management;Alternative evaluation: choice of different options in URTI management;Antibiotic obtaining: how to obtain antibiotics;Antibiotic consumption: how to use antibiotics;Post-consumption evaluation: perceived outcomes of antibiotic use.The data were coded under each step through an induction approach following Braun and Clarke's guidelines , which iThe prevalence range of irrational behaviors of the public in antibiotic usage was reported without meta-analyses due to the high heterogeneity of the included quantitative studies (including the quantitative components of the mixed method studies). The driving forces of the irrational behaviors were categorized into three categories according to the COM-B framework : CapacitPatients and the public were not involved in this systematic literature review.A total of 8,544 articles were identified and 114 met the inclusion criteria. The further appraisal of the risk of bias excluded 28 studies (27 quantitative and one mixed), which resulted in a final sample size of 86 studies for data syntheses: 48 quantitative, 30 qualitative, and 8 mixed methods .n = 37; 43.0%) of the studies in the final sample were published after 2010 (n = 29), Asia (n = 27) and North America (n = 21) and assessed the behaviors of patients (n = 46), their parents or caregivers (n = 31), or both (n = 9). Details of the characteristics of the included studies are presented in the Roughly half (ter 2010 . They wen = 33) (n = 32) (n = 35) (n = 23) (n = 15) (n = 21)  , 120, in(n = 32) , 120, an(n = 35) –117, 120(n = 23) –117, 120(n = 15) , and pos(n = 21)  (Quotes (n = 21) .Of the 53 studies containing a quantitative component, 18 studies , 96–101 Eleven themes emerged covering the six CBM stages: need recognition, information searching, alternative evaluation, antibiotic obtaining, antibiotic consumption, and post-consumption evaluation. The six stages reinforce each other, resulting in a vicious cycle .This is the first stage in which people self-assess the need for taking further actions. It involves symptom recognition, cause attribution, and illness labeling.URTIs are highly recognizable, as patients usually experience typical symptoms , 50, 73,URTIs are considered infectious. Environmental factors , 90, 115Labeling is a critical step that shapes decisions for further actions. URTIs can be labeled as a minor or severe condition , 76, 84 Concerns about diagnostic uncertainty and trajectory uncertainty contribute to the labeling . The forThe quantitative studies confirmed that the perceived seriousness of symptoms , 96, 98,Individual vulnerability is also taken into consideration in the labeling. A lower threshold of severe labeling is adopted for vulnerable populations such as children , 88, 90.Information acquisition can shape or change people's understanding and attitudes toward URTIs and its treatment. Two major themes were identified in association with the impacts of acquired information: authenticity and usability.People often feel that it is difficult to obtain helpful information for decision-making regarding URTIs . MultiplThe public usually gives the highest authenticity to information provided by healthcare providers (HCPs) , 93, 94,Lessons learnt from personal experience serve as another important source of information , 119. ThPeople also seek information from others through their social networks , 94, 117People can get access to relevant information via traditional  or/Useful information needs to have valid content –90, 93 aAt this stage, people use their knowledge and gathered information to evaluate alternative approaches to URTI management.People are aware of the existence of a diverse range of treatment regimens for URTIs including traditional therapies, over-the-counter (OTC) medicines, and antibiotics , 115–117The treatment regimens adopted by patients with URTIs can be grouped into three categories, namely home remedies, HCP-prescribed treatments, and antibiotics.Home remedies are considered appropriate for minor conditions , 90, 115Consultations with HCPs are anticipated when the condition is labeled as severe or the symptoms are worsening despite the application of a home remedy , 95, 116Antibiotics are perceived as a strong treatment regimen for severe URTIs , 117. SuIt is evident that most people do not understand how antibiotics function , 95, 117Antibiotics can be obtained from prescriptions or pharmacy retail outlets (without a prescription), or they can be left over from previous prescriptions.Although not all patients expect HCPs to prescribe antibiotics for URTIs , 91, 117Perceived effectiveness and added value are the major reasons for requesting antibiotics, according to qualitative studies , 116. SuOverall, the public feels it is increasingly difficult to obtain antibiotic prescriptions for URTIs , 84, 88.In some systems, antibiotics can be obtained from pharmacy retail outlets without a prescription , 117. PeLeftover antibiotics are very likely to be used for similar conditions, including URTIs , 87, 88.In terms of the overall prevalence of antibiotic self-medication, 11 studies show that the rate ranges from 6.2 to 42.3% . MongoliPerceived severity [intensity of symptoms , 96, preURTI patients take a pragmatic approach and adjust the uptake of antibiotics through self-assessment of their conditions. They weigh the perceived benefits against risks continuously , 83, 88 Five quantitative studies , 75, 98 Personal experience of antibiotic use for URTIs feeds into future decision making. Recovering from URTIs whilst taking antibiotics can enhance the misbelief that antibiotics are a strong medicine for URTIs and can lead to an acceptance of the side effects of antibiotics.URTIs are a self-limiting condition. Relief of symptoms is considered an indication of the effectiveness of medicines, including antibiotics . This enPeople are aware of the potential side effects of antibiotics, including concerns about antibiotic resistance. Such knowledge can be obtained from their personal experience , 74 or tThere is optimism for the future. Many believe that new antibiotics will be available to deal with antibiotic resistance , 91, 92,People are also aware of the other side effects of antibiotics , 91, 92,This mixed methods systematic review identifies several types of presentations in the public's irrational use of antibiotics for URTIs, including antibiotic expectations, demand for antibiotic prescriptions, self-medication with antibiotics, purchase of antibiotics without a prescription, and non-adherence to medical instructions. The synthesis of the quantitative data indicates widespread irrational antibiotic use for URTIs internationally and highlights the importance of the motivation factor as a driving force. High levels of concerns about the severity of the condition and misbelief in the efficacy of antibiotics for treating URTIs were consistently found to be associated with the irrational use of antibiotics, whereas, individual capacity and opportunity, the other two factors corresponding to the COM-B framework, showed mixed effects in the existing studies.The synthesis of the qualitative data generated eleven themes in line with the six CBM stages: need recognition, information searching, alternatives evaluation, antibiotic obtaining, antibiotics consumptionand post-consumption evaluation. The public are confident in recognizing URTIs. They tend to categeorize their condition into a minor or severe case without using a clear set of criteria. They obtain information from a wide range of sources and those derived from their own personal experiences and from the HCPs are the most valued in their decision making. Potential treatments are rated based on perceived effectiveness and efficacy and antibiotics are highly likely to be rated as a strong medicine for URTIs. The public also attach additional value to antibiotics beyond treatment for URTI. Apart from prescriptions obtained from HCPs, some patients also purchase antibiotics from pharmacy retail outlets without a prescription and use leftover products for self-medication. The continuation or suspension of antibiotic uptake usually depends on self-assessment of the benefits against the risks, leading to poor adherence to medical instructions (if applicable). Because of the self-limiting nature of URTIs, the public are likely to misattribute their recovery to the effect of antibiotic treatments, reinforcing their belief that antibiotics are a strong medicine for URTIs. Although they are often aware of the association between antibiotic use and AR, they tend to perceive AR as being of little relevance to themselves, especially when they consider themselves to be a low user of antibiotics. There is optimism in the public in relation to human responses to AR, which downplays individual responsibilities. These actions form a vicious cycle, making it a very challenging task to reduce antibiotic use for URTIs.To the best of our knowledge, this is the first mixed methods systematic review on the public's use of antibiotics for URTIs. The synthesis of data was guided by the COM-B (for quantitative data) and CBM  frameworks. Further integration of the quantitative and qualitative findings has helped us to comprehensively understand the public's behaviors in relation to antibiotic use for URTIs. The public's behaviors over the entire process, which starts from symptom recognition and ends with a final reflection of personal experience, form a vicious cycle, fueling public expectations on antibiotic use for URTIs. The findings have significant implications for policy development and interventional designs.This review focuses on antibiotic use for URTIs due to its high prevalence and the importance of tackling the irrational use of antibiotics. Attempts to generalize the results to other conditions should be cautious. In this study, we did not perform meta-analysis on the quantitative studies because of the high heterogeneity of the findings. We also note that there is a lack of standardized approaches in monitoring the public use of antibiotics, leading to varied measurements.This review shows that the public overuse of antibiotics for URTIs is prevalent worldwide. This result is consistent with the findings of the public's antibiotic use in general , 122. HoThe underlying reasons for the public overuse of antibiotics are multifaceted according to the COM-B framework. There is consistent evidence to support the association between individual motivation and the overuse of antibiotics. However, no definite conclusions can be made for the roles of individual capacity and opportunity: the results of the existing studies are mixed. It is likely that their effects are context-dependent. In most settings, high levels of individual capacity  have been found to be associated with the appropriate use of antibiotics , 114. HoThe recent series of studies in the UK , 99 showThis review decomposes the decision-making process of the public regarding antibiotic use for URTIs into six intertwined stages in line with the CBM framework. They reinforce each other, forming a vicious cycle. The inappropriate use of antibiotics is facilitated by the misinterpretation of the illness condition fueled by misinformation obtained from multiple sources (including past experience of antibiotic use for URTIs) and easy access to antibiotic products. Health regulators, HCPs, consumers, and social media all play a role.In countries where antibiotics have been frequently used for treating URTIs, consumers tend to exert great pressures on HCPs to prescribe antibiotics , 107. QuHCPs are highly valued by the public for their medical advice, including advice in relation to URTIs , 93, 94.The findings of this study have significant policy and practice implications. A systems approach is needed to break the vicious cycle in the public overuse of antibiotics for URTIs. Interventional measures must consider the interactions between HCPs and consumers and address the issues relating to all the six steps in consumer decision making.The public should be educated to take responsibility to protect the health and wellbeing of not only themselves but also society through the rational use of antibiotics . Social Intervention strategies targeting misinformation are critical to enable consumers to make proper decisions regarding antibiotic use . HCPs arRegulations and law enforcement need to be strengthened in some countries . Many anThe overuse of antibiotics in the public for URTIs is prevalent worldwide. It results from both an over-prescription from HCPs and self-medication by consumers. Consumers are motivated to use antibiotics by a series of intertwined factors that form a vicious cycle. These include misinterpretation of the illness condition, misinformation shared by others, over-prescription by HCPs, poor adherence to medical advice, easy access to antibiotic products, and misjudgment of personal experience. A systems approach is required to break the vicious cycle. HCPs share the responsibility in re-shaping public attitudes toward antibiotic use for URTIs. Their communication and prescribing practices form an integral part, but not all of the decision process of the public. This calls for interventions concerning both supply-side and demand-side drivers.The original contributions presented in the study are included in the article/CheL: conceptualization, data curation, formal analysis, funding acquisition, investigation, methodology, resources, software, supervision, validation, visualization, writing—original draft, and writing—review and editing. ChaL: conceptualization, investigation, supervision, and writing—review and editing. XZ: conceptualization, investigation, resources, supervision, and writing—review and editing. LD: formal analysis, data curation, methodology, project administration, software, validation visualization, and writing—original draft. DW: formal analysis, data curation, methodology, and project administration. RL and PQ: data curation, formal analysis, and project administration. All authors have read and agreed to the published version of the manuscript.This study was funded by the National Natural Science Foundation of China (grant no. 71904053). The funding body played no part in the study design, collection, analysis and interpretation of data, writing of the manuscript or the decision to submit the manuscript for publication.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.All claims expressed in this article are solely those of the authors and do not necessarily represent those of their affiliated organizations, or those of the publisher, the editors and the reviewers. Any product that may be evaluated in this article, or claim that may be made by its manufacturer, is not guaranteed or endorsed by the publisher.


Poor biological attachment of artificial reef (AR) prepared by the recycled aggregate limit the application in the area of marine engineering. In this study, the waste oyster shell (WOS) was used as raw materials to prepare the recycled aggregate porous concrete (RAPC), the compressive strength, split tensile strength, chloride penetration resistance, freezing-thawing resistance, low temperature resistance, and the biological attachment were tested, aiming to improve the biological attachment and decrease carbon dioxide emission. The experiment results demonstrate that the use of WOS can decrease the compressive and split tensile strength, but the effect of designed porous structure on the mechanical strength is higher than that of WOS. To ensure the durability of RAPC, the contents of WOS should not exceed 20%. Additionally, the addition of WOS and designed porous structure are beneficial to biological attachment. However, the porous structure of RAPC only improves biological attachment in the short term, and the reverse phenomenon is true in the long term. As the partial replacement of cement with WOS is 40%, the total carbon dioxide emission decreases by about 52%. In conclusion, the use of WOS in the RAPC is an eco-friendly method in the artificial reef (AR) with improved ecological attachment and reduced carbon dioxide emission. Waste management is one of the most worldwide problems, such as construction and demolition waste (CDW) and aquacultural waste (AW), leading to lots of economic losses and environmental threats caused by their heaps ,2, and sIn China, as a kind of AW, the output of WOS can reach 12–15 million tons per year ; some stAR is a man-made structure in the sea, aiming to provide suitable habitats for marine life, enhance fisheries, and capture biological carbon ,15. ConcHowever, AR prepared with porous concrete presents poor biological attachment. Therefore, in this study, the WOS was used as raw materials to prepare the RAPC, aiming to improve the biological attachment and decrease carbon dioxide emission. To ensure the durability of RAPC, the chloride penetration resistance, freezing–thawing resistance, and low temperature resistance were tested. Furthermore, marine ecology was used to investigate the species distribution of attached organisms and the stability of the ecosystem. Meanwhile, the use of WOS plays an important role in reducing carbon dioxide emission.Ordinary Portland cement  was used as the cementitious materials and WOS  was used as the inert filler, with the physical and chemical properties of these in (1)The WOS powder and cement were firstly mixed in the concrete mixer for 30s;(2)Water reducing agent was dissolved in the water and then to add and mix in the concrete mixer for 60s;(3)The recycled aggregate was mixed with the above cement paste for 90s to get the fresh concrete;(4)The prepared RAPC was cast into the molds and subsequently removed from the molds after 1d;(5)The specimens were cured at a temperature of 20 ± 2 °C and humidity of 95% RH.The flow chart of prepared specimens was shown in T-SR is the tension-compression ratio of specimen, dimensionless; sf is the compressive strength of specimen, MPa; tf is the split tensile strength of specimen, MPa.According to GB/T 50081–2019 , the comRCMD is the non-steady-state chloride migration coefficient, ×10−12 m2/s; T is average initial and final temperatures in anolyte and catholyte solutions, °C; L is specimen thickness, mm; U is applied voltage, V; t is test duration time, h; dX is average penetration depth, mm.sQ is electric flux, C; I0 is initial current, A; tI is current at t min, A;According to GB/T 50082–2009  and ASTMmiD is mass loss rate, %; Di0 is initial weight of specimen, g; niD is the weight of the specimen under n times freezing–thawing cycles, g; mD is the average mass loss rate, %.sD is strength loss rate, %; cW0 is the compressive strength of specimen cured in the standard curing chamber, MPa; cnW is the compressive strength of specimen on freezing-thawing cycles after n times, MPa.According to GB/T 50082–2009 , the slofK is the coefficient of compressive strength, %; cnL is the compressive strength of the specimen on low temperature after n days, MPa; cL0 is the compressive strength of specimen cured in the standard curing chamber, MPa.The low temperature testing machine  was used for testing the resistance of concrete to low temperature. The test specimens were stored in testing machine after being cured for 28 d, and the temperature was set to 2 °C. The specimens were taken and tested for compressive strength at the end of 30 d, 60 d, and 90 d, respectively. The coefficient of compressive strength is calculated by Equation (6).The prepared concrete was immersed in the sea located in Rizhao, China. The depth of immersion was 2 m below the surface of the seawater at low tide level, aiming to reduce the effects of environmental changes and ensure the immersed condition, as shown in The specimens were operated as follows. Firstly, specimens were re-floated and photos taken, then attached organisms were obtained using a scraping tool from the area of 100 mm × 150 mm. Subsequently, the attached organisms were brought to the laboratory using a glass bottle and adding 10% formaldehyde solution (50 mL) to fix with the organisms. The test program for biological identification was as follows. Firstly, the specimens in the glass bottle were mixed and then dropped onto the glass slide using a dropper. Inverted microscopes  were used to observe the specimens and check into the China Species Library. Finally, the observed specimens were re-collected and dried until their weight no longer changed (temperature was 105 °C ± 10 °C).P is the biological attachment index, kg/m2; m is the dry weight of attached organisms, kg; s is taken specimens area, m2.J is the Pielou evenness index, dimensionless; S is species number of attached organisms, number/50 mL; iP is the particular organism to the total organism ratio, dimensionless.The biological attachment was evaluated by two methods: (1) the visual assessment using a macrograph; (2) biological identification. Additionally, the biological attachment index, Shannon-Wiener index and Pielou evenness index, calculated by Equations (7)–(9), respectively, provide complementary data to evaluate the biological attachment.3 concrete in this process”. According to related standards and research, the carbon dioxide emission factor of mainly energy and composition in concrete were shown in 2-eq/t [C is the total carbon dioxide emission of concrete, kg CO2-eq; rC is the carbon dioxide emission of raw materials, kg CO2-eq; wosC is the carbon dioxide sequestration of WOS as raw material, kg CO2-eq; bioC is the carbon dioxide sequestration of biological attachment, kg CO2-EquationiF is the carbon dioxide emission factor of i type of raw material, kg CO2-eq/t; im is the weight of i type of raw material in 1 m3 concrete, t.wosE is the carbon dioxide sequestration factor of WOS, kg CO2-eq/t; wosm is the weight of WOS as raw material in 1 m3 concrete, t.bioE is the carbon dioxide sequestration factor of biological attachment, kg CO2-eq/t; ε is 0.95 meaning the related index, dimensionless; biom is the dry weight of biological attachment in 1 m3 concrete, t.This study evaluated the carbon dioxide emission of concrete within the boundary, including the preparation and transportation of raw materials, and the carbon dioxide sequestration of biological attachment. The function unit was defined as “1 mn 2-eq/t .(10)C=CThe mechanical properties of concrete are evaluated by compressive strength and split tensile strength, as shown in Furthermore, due to the impact effect of sea waves, the AR will suffer from vertical compressive, horizontal split tensile and shear stresses in the seawater. Therefore, the brittleness of concrete is investigated. The tension-compression ratio is used to assess the brittleness of concrete, as shown in The non-steady state chloride migration coefficient and electric flux are used to evaluate the chloride penetration resistance, as shown in Compared with CR, the non-steady-state chloride migration coefficient and electric flux of RAPC decrease by about 37% and 39%, respectively. The reason is that RA with micro cracks and high water absorption will lead to a weakened ITZ . TherefoThe freezing–thawing resistance of concrete is evaluated by the average mass loss rate and the strength loss rate, as shown in After 50 times of the freezing–thawing cycles, as the replacement rate of WOS is 20%, the average mass loss rate and the strength loss rate of RAPC increase by 12% and 5%. The weight and strength loss rate of RAPC meet the requirements of GB/T 50082-2009 . HoweverAfter 75 times of the freezing–thawing cycles, as the partial replacement of cement with WOS is 0, 20, and 40%, the average mass loss rate and the strength loss rate increase by 12~25% and 7%, respectively. The specimen of PW40 has been broken and lost strength, as shown in The coefficient of compressive strength is used to evaluate the low temperature resistance of concrete, as shown in The state of all specimens is observed differently, and the macrograph of the growth state for attached organisms is as shown in Compared with CR, RAPC is beneficial to the biological attachment in 1 month due to the bigger specific surface area and rougher surface. As marine life is carried by seawater across the RAPC surface, some organic small molecules are rapidly accumulated, such as polysaccharides, proteins, etc., and biofilm is formed on the surface ,46. SubsBiological identification and three indexes at different times were used to further assess the biological attachment. The species of biological identification and three indexes at 1, 3, and 6 months are shown in In summary, the addition of WOS and design of RAPC are effective methods to increase the biological attachment of concrete toward the use of AR. The biological attachment, the richness of the biocenose and the stability of the ecosystem is improved. However, compared with CR, the improvement of biological attachment in the RAPC only exists in the short term, and a negative effect is presented in the long term due to the high pH value on the surface of concrete.The total carbon dioxide emission is used to evaluate the carbon reduction effect, as shown in In summary, the use of WOS is a potential method to reduce carbon dioxide emission. Further, the designed porous structure should be paid attention to and combined with practical application. Although its rough surface can increase biologically in the short term, a high carbon dioxide emission is adverse to the environment.(1)The addition of WOS can decrease the compressive and split tensile strength, but the effect of designed porous structure on the mechanical strength is higher than that of WOS.(2)To ensure the durability of RAPC, the contents of WOS should not exceed 20%.(3)The addition of WOS and designed porous structures are beneficial to the improvement of biological attachment. However, the porous structure of RAPC only improves biological attachment in the short term, and the reverse phenomenon is true in the long term.(4)As the partial replacement of cement with WOS is 40%, the total carbon dioxide emission decreases by about 52%.In this study, the WOS was used as the raw materials to prepare the RAPC, aiming to improve the biological attachment and decrease carbon dioxide emission. In conclusion, the use of WOS in the RAPC is an eco-friendly method in the AR with improved ecological attachment and reduced carbon dioxide emission. The main conclusions are highlighted below:


The molecular mechanisms for the inward electron transfer pathway have been the subject of intense debate for quite some years  are supported by some experimental evidence. The participation of H2 in the EET seems to be strain‐ and environmental condition‐dependent. In this special issue,  inducers, the respective costs can increase quite significantly—especially when considering demands at an industrial scale. Using cheap, renewable electricity to induce gene expression is a good alternative to enhance the economic feasibility of a biosynthetic process. In 2017, electronic control of gene expression was reported in Tunable (or even self‐tuning) gene expression is also desired at different process phases. A genetic toggle switch was reported in 2000 , which is vital for direct EET. Other members of the genus also show high resistance to environmental stress and harbour, e.g., halophilic pathways and/or lipid production pathways, making them great candidates for electrobiosynthesis of chemicals that are typically toxic to other microorganisms. However, like many other non‐native electrogens, there are big knowledge gaps on how Marinobacter can interact with the electrode and the application potentials determined by, e.g., the EET rate—among other open questions. Genetic engineering tools should also be developed to tailor Marinobacter genotypes in the MET system for the desired purpose.The characteristics and potential of another non‐model MET microorganism for MET research, d et al.  in this Among non‐model electroactive microorganisms, purple phototrophic bacteria (PPB) are also recently attracting considerable attention for their photoelectroautotrophic metabolism, which holds promise in the broad context of carbon fixation. Along this line, Manchon and colleagues  and iMETland (Spain) technologies. Bridging the ‘valley of death’ between lab‐based processes and industrial applications is critical for the continuous growth of MET.Geobacter sulfurreducens and they found that the mutants could form 45% to 70% thicker biofilms. Higher total power outputs were achieved with these engineered strains as compared to the wild‐type, and the specific power output normalized to the biomass content was likewise enhanced. How long this positive correlation between biofilm thickness and specific biofilm activity could last  will be the subject of future research.Most MET studies are based on biofilm platforms. The electrochemical activity of biofilm intrinsically determines the overall turnover rate—thus, the upper process boundaries for potential application scenarios. One key problem is decreasing biofilm activity with increasing biofilm thickness, mainly due to the mass and electron transfer limits within the biofilm. In this special issue, (Wang, et al., The article indicated above reports a clear example of how synthetic biology can help to tackle the current challenges towards the broad application of MET. Similar concepts can be adapted to other scenarios. To realize all these potentials, a deeper understanding of the MET process will be critical. In this special issue, (Atkinson, et al., In summary, several examples in this special issue underscore the synergies between MET and synthetic biology. Both fields will gain unique new opportunities and potentials by integrating with each other. Quantitative understanding and the subsequent rational design will be challenging—but they also constitute the basis for future developments at different levels of implementation.Bin Lai drafted the manuscript. Jens Krömer, Federico Aulenta, Hui Wu and Pablo Ivan Nikel reviewed and edited the draft. All authors read and approved the final paper.The authors declare no conflict of interest regarding the content of this editorial.


Transitions of care also exist within the operating room and contribute to an increased risk of adverse events.Hospitalized patients with severe infections may warrant intravenous (IV) antibiotics and surgical intervention for effective treatment of their infection. Surgical interventions require multiple transitions of care, which are well-studied sources of medication-related errors and inappropriate antimicrobial use. Furthermore, intraoperative bacteremia is common during elective surgeries. For patients requiring surgery for infection source control, maintaining adequate serum antibiotic levels may be particularly important in preventing bacteremia while infected tissue is surgically manipulated.Errors in antibiotic use in the perioperative period may negatively affect patient outcomes. Patients who experience diminished serum and tissue concentrations of antibiotics during surgical closure have higher risks of postoperative wound infections. no studies have investigated perioperative antibiotic use for inpatients already on IV antibiotic regimens. The lack of guidelines introduces further complexity because it allows for additional and potentially inappropriate antibiotic administration for patients already receiving broad-spectrum antibiotics. In this study, we examined the incidence and nature of inappropriate antibiotic use in the perioperative period among inpatients on IV antibiotic regimens.Although data exist on optimal timing of antibiotic administration for surgical antimicrobial prophylaxis,We conducted a retrospective cross-sectional study at a Veterans’ Affairs medical center. We included all inpatients who underwent noncardiac surgery in 2019 who were aged >18 years or older and were on an IV antibacterial regimen prior to surgery. Patients receiving only surgical antimicrobial prophylaxis were excluded. Study and waiver of consent were approved by the Institutional Review Board of the VA Ann Arbor Healthcare System.Through manual chart review by 2 physicians, we collected information on prescribed IV antibiotic regimens and timing of antibiotic doses in the perioperative period. Errors were classified as follows: missed doses, delayed doses, additional doses of prescribed IV antibiotics, or additional surgical antimicrobial prophylaxis. Delayed antibiotics were administered between 2 and 4 hours after the scheduled administration time, and missed antibiotics were either omitted or administered at least 4 hours after the scheduled administration time. Administration of surgical antimicrobial prophylaxis was defined as an error in patients already receiving IV antibiotics with the same or broader antimicrobial coverage.Of the 290 inpatients who underwent surgery in 2019, 163 patients (56%) received an IV antibiotic regimen prior to surgery. Complete data were available for 153 patients (94%). Errors in antibiotic administration in the perioperative period were identified in 60 patients (39%). The most common error was a missed dose of an IV antibiotic, which occurred in 22 patients (39% of errors)  was a missed dose of an antibiotic. Also, antibiotic overuse  accounted for 36% of errors. For example, patients already on broad-spectrum antibiotics for their infection were given additional antibiotics  for surgical site infection prophylaxis. We suspect that these errors are related to the multiple transitions of care in the perioperative period. Some errors are also likely related to documentation of medications administered during an anesthetic in a separate part of the electronic medical record than medications administered on the hospital ward.This study had several limitations. This was a single-center, retrospective study, and including multiple VA institutions would be a powerful next step. Second, the generalizability of these results may be limited because institutions using other electronic medical records may have different processes for documentation. However, we believe that the presurgical period in a patient’s hospitalization represents an underrecognized opportunity for antimicrobial stewardship given the transitions of care involved. and misuse of antibiotics is common in these patients. Education-based stewardship interventions and clinical decision support tools implemented in surgical units have been shown to lead to reductions in antimicrobial consumption and improved trends in percentages of resistant bacterial strains. However, research evaluating interventions that specifically target perioperative antibiotic misuse for inpatients already on antibiotics for active infections is limited. This period may present a valuable opportunity for multidisciplinary stewardship intervention. Collaboration between antimicrobial stewardship programs, anesthesiology, and surgery departments should be encouraged to improve local practices in perioperative antibiotic prescribing and to address systems-based challenges that lead to inappropriate antibiotic use. Further research will be essential to the evaluation of outcomes of patients who experience errors in perioperative antibiotic administration.In conclusion, surgical patients account for significant proportions of inpatient antibiotic use,