The reinforced concrete structures that support transport, energy and urban networks in developed countries are over half a century old, and are facing widespread deterioration. Geopolymers are an affordable class of materials that have promising applications in concrete structure coating, rehabilitation and sensing, due to their high chloride, sulphate, fire and freeze-thaw resistances and electrolytic conductivity. Work to date has, however, mainly focused on geopolymers that require curing at elevated temperatures, and this limits their ease of use in the field, particularly in cooler climates. Here, we outline a design process for fabricating ambient-cured fly ash geopolymer coatings for concrete substrates. Our technique is distinct from previous work as it requires no additional manufacturing steps or additives, both of which can bear significant costs. Our coatings were tested at varying humidities, and the impacts of mixing and application methods on coating integrity were compared using a combination of calorimetry, x-ray diffraction and image-processing techniques. This work could allow geopolymer coatings to become a more ubiquitous technique for updating ageing concrete infrastructure so that it can meet modern expectations of safety, and shifting requirements due to climate change. Coating technologies are an effective means of protecting concrete structures from chemical attack and rebar corrosion. Inorganic coatings in particular have been widely applied as anticorrosive and decorative materials for concrete and steel structures ,2,3,4. TRegardless of the application, a good coating will be free of cracks and defects. Integrity is an ongoing issue regarding the development and practical application of geopolymer coatings. Some common concerns include cracking due to shrinkage, changes to setting times and efflorescence ,29,30. TIn this work, we aimed to develop high-quality, ambient-temperature-cured fly ash geopolymer coatings. We wished to achieve this with minimal additional processing steps (such as fly ash grinding or the use of additives), so as to minimize manufacturing costs and complexity. This was challenging: geopolymers are typically cured at elevated temperatures to accelerate geopolymerisaton, as rapid curing allows coatings to achieve a higher early-age strength ,32,33,34The notable contributions of this paper are four-fold: (i) we present an affordable process for ambient-temperature geopolymer synthesis that does not require additives or grinding; (ii) we outline the influence of prolonged mixing times on coating quality , aluminum (Al) and oxygen (O). For an excellent introduction and description of geopolymer systems, readers are directed to . TypicalThe mass ratio, L/A;The mass ratio, SH/SS;The molarity of the SH .The alkaline activator solution (L) used in this work was rather typical: a combination of sodium hydroxide (SH) and sodium silicate (SS) . The cheWhile molarity can, to some extent, be selected based on safety considerations, the ratios L/A and SH/SS should be selected to match the chemical composition of the fly ash. This is a significant drawback for fly ash geopolymers, as: (i) fly ash composition can vary significantly between coal plant sources; and (ii) unlike with Portland cement systems, there are no simple numerical methods for geopolymer mix design, particularly for fly ashes ,56. The Repair works, including coatings, aim to preserve or restore concrete structures . The serFor geopolymer coatings cured on concrete at ambient temperatures, shrinkage is the most significant issue . ShrinkaDrying shrinkage is the result of a loss of water from the geopolymer’s capillary pores. This loss of moisture causes the tension in the capillary pores to increase, resulting in a volume reduction in the specimen. When geopolymer coatings cure, they undergo this shrinkage while simultaneously binding to the underlying concrete substrate. The resulting confinement allows shrinkage strains to cause tensile and shear stresses. If significant shrinkage occurs before the coating has adequately cured, these stresses will exceed the strength of the geopolymer , leadingFor concrete coatings, there are at least two major contributors to drying shrinkage, illustrated in As both drying mechanisms are surface-area dependent processes, the edges of geopolymer patches are particularly prone to cracking, as these edges can present an extra surface for evaporation. One clear way of tackling this issue is to accelerate the curing rate of the geopolymer coating (and this is why elevated temperatures are often used). Grinding fly ash particles to improve their reactivity and allow room temperature curing, as in , may appHigh surface tension: this plays a key role in the ability of the materials to bind and stay bound to substrates. A reduction in surface tension may, in some cases, be required to ensure good adhesion . With reThixotropic Bingham plastic fluid behavior: most geopolymers show history-dependent rheological behavior, and can be kept in fluid form if subjected to constant shearing ,68,69. TSetting times that are strongly dependent on chemical composition: the setting time of geopolymers can range from minutes to hours and depends on geopolymer composition. Setting times can be reduced by lowering Si/Al ratios, or by increasing calcium (Ca) content . For sysOne of the most common ways to apply cementitious coatings to concrete in the field is by pumping and spray coating. There have also been lab studies that demonstrated (as is shown in this work) the application of geopolymer coatings with a trowel , and eveThe impact this has on coatings is that it can be challenging to independently tune adhesion, rheology, setting time and shrinkage behavior, as the properties of the system are highly interdependent. Therefore, previous work conducted at elevated temperatures may not always map onto efforts to produce geopolymer coatings that cure in ambient conditions.Previous studies have found that the adhesion of coatings more generally is strongly influenced by the roughness of the substrate surface, its water content and the mix composition of the coating material ,76,77,78Some authors ,82,83 haToday, opinions diverge about the most appropriate practice when coating and repairing concrete substrates. Even between international codes of practice, recommendations are contradictory. The AASHTO-AGC-ARTBA Joint Committee recommends a dry surface for concrete, except on dry and hot summer days, while the Canadian Standards Association Standard A23.1 recommends wetting the surface for at least 24 h before casting the new concrete . In someA final issue, which can be particularly prevalent in ambient temperature cured geopolymers, is efflorescence. Efflorescence is the formation of white salt deposits, and it can unfortunately occur during attempts to manipulate geopolymer shrinkage, adhesion, workability and setting time. It has been found that efflorescence is due to many factors : wet conIn this work, geopolymers were synthesized from low calcium fly ash. According to standard BS EN 450, the fly used was class B for Loss On Ignition (LOI) of 2.0% to 7.0%, and category S for fineness (no more than 12% retained on the 45 micron sieve). Under US notation, according to ASTM C 618-19, the fly ash used in this work would be considered class F. The chemical compositions of the fly ash used is given in 2SiO3), with the NaOH/ Na2SiO3 ratio equal to 0.4. This is in accordance with our previous work [2O and 27.8 wt% SiO2, in distilled water. The Na2O and SiO2 concentrations of the alkaline activator were 12.7 wt% and 19.9 wt%, respectively, and the remaining 67.4 wt% was deionized water. The activator was made 24 h prior mixing, to allow the heat of any exothermic reaction to dissipate. The alkaline activator used in this work was made by combining 10 wt% of 10 M sodium hydroxide solution (NaOH) and 24 wt% sodium silicate solution  = 0.5. According to Nedelikovic et al., L/S = 0.5 improves workability, without having a significant effect on compressive strength . A highe−1  of geopolymer coatings were applied to concrete substrates in this work. Thin coatings were around m = 1 mm, and thicker coatings were m = 3 mm. These thicknesses were chosen in accordance with the requirements for sensing [Two thicknesses  remain filled at relative humidity (RH) values of 50% and higher ,90. As aThe surface roughness of each concrete substrate used was measured by 3D laser scanning . The values for surface roughness were determined by analyzing the root mean square deviation of the point cloud from a mean plane. Typical values of surface roughness for concrete samples are shown in Geopolymer specimens were batched and placed within one of two curing conditions, summarized in All geopolymer specimens in the batches were left to cure for 28 days. While geopolymers do tend to cure much faster than Portland cement mixes, we opted to use a prolonged curing duration in this work to ensure that patches were fully cured and stabilized in ambient conditions.Several tests were carried out on the fly ash powder and the geopolymer binder to characterize their properties, before mixing, during curing and after curing. These are summarized in the following sections.The setting time of geopolymer mixes was measured using the Vicat needle test, following the procedure outlined in BS EN 196, part 3 . This teA thermal analysis, together with an evaluation of setting time using the Vicat needle test, can be used to define an optimized time for applying geopolymer coatings to concrete substrates. In this work, an isothermal calorimeter  was used to measure the temporal dependence of the heat produced by the exothermic reactions occurring in the geopolymer from immediately after mixing up to 3 days. Tests were conducted three times for each geopolymer mix tested, with the averaged heat curve presented in the results.X-ray diffraction (XRD) analysis was carried out on samples of fly ash, on geopolymer layers and on geopolymer coatings, which had demonstrated efflorescence. All XRD data was collected using a Bruker D8 Advance instrument. Data for Rietveld refinement was collected in Bragg-Brentano geometry from 12°–75° 2theta with an increment of 0.02 °/s and a step time of 0.8 s. using a divergence slit of 0.23°. A Ni β filter was placed in the incident beam path. The sample was rotating at 30 rpm and a knife edge collimator was used to reduce air scattering. 210/I120) of mullite to estimate the mineral’s Si/Al ratio, was used to choose the most appropriate structure file to include (ICSD collection code 66449) in the TOPAS refinement. They showed a linear relationship between x in the mullite general formula (Al4+2xSi2-2xO10-x) and the 210/120 reflection intensity which was used here to calculate x = 0.28 for the Cemex fly ash. The efflorescence was analyzed intact on a sample of geopolymer. The efflorescence could not be easily removed for conventional powder analyses and was analyzed in situ in the XRD using a Goebel mirror. Data was collected from 10°– 60° 2theta with an increment of 0.02 °/s and a step time of 8 s. Quantitative analysis was carried out using the internal standard method by adding 10 wt% silicon to the ground powder samples, and TOPAS software. ICSD structure files used in the refinement are listed in caption of Figure 15. The method proposed by Williams and van Riessen , which uCompressive strength tests were conducted with a small loading cell with the speed of 2 mm/min on geopolymer cubes of side 30 mm. Tests were conducted after 1 day, 2 days, 3 days, 4 days, 7 days, 14 days and 28 days. The intention here was to demonstrate the evolution of strength, rather than strictly comply with strength-testing standards.A visual inspection was often enough to provide a binary “yes/no” assessment of whether a geopolymer coating had cracked after curing. However, to quantify the relative levels of cracking between specimens in a less subjective manner, we developed a simple image processing technique outlined in The original sample images were taken using a DSLR  camera with a set distance between the sample and the focal lens. The image was then cropped so that all samples produce images of the same size for ease of comparison. The color images obtained were converted to grayscale images. This eliminated colors during further processing, while preserving the intensity of each pixel in the image with a grayscale level. In order to ensure that the cracks are the darkest part of the image, a pre-processing step of intensity adjustment was required. The bottom 1% and the top 1% of all pixel values were saturated to increase the contrast of the output image. By identifying and intensifying the pixels below the mean grayscale value in the image, a clearly distinguished foreground of cracks was obtained, as shown in During the image acquisition step, the inconsistent amount of light in the background was difficult to avoid. In order to correct for this non-uniform illumination, adaptive binarization was used. By applying Bradley’s method, each pixel in the integral image was compared to the average grayscale level of its surrounding pixels and set to a binary value accordingly .Due to the special characteristics of cracks in our samples, morphological operations and dot detection could be used to reduce noise that will interfere with the final quantification of cracking . One pixThe final step was to calculate the percentage of dark pixels (cracks) over the area of the whole image, yielding a quantified and less subjective result for the levels of cracking in each sample. This result was provided as a percentage of the image that showed cracks.The evolution of the compressive strength of the geoploymer is shown in The main finding of this investigation was related to the thickness of the geopolymer coatings applied onto the concrete specimens. These results are shown in This finding was initially surprising: the lower surface/volume ratio of the 3 mm thick coating should allow the geopolymer to retain more water. The result was also at odds with previous work by Zhang et al. , who conThe thicker coatings in The reason for cracking in these coatings more generally can be explained using Finally, a Vicat Needle test produced the setting times shown in The results in this work showed that the age of the concrete substrate had little to no influence on the integrity of the coating layer: the coating thickness and the mixing time of the geopolymer were far more important factors. However, this does not rule out the effect of concrete age on water absorption from the geopolymer layer in all cases, as the rate-of-hydration and pore-size-change within concrete substrates are strongly dependent on the concrete’s water/cement ratio, the cement particle size and the curing conditions. Nevertheless, this result, together with the independence of the integrity of the coatings on the curing RH levels between 50% and 95%, was encouraging from the standpoint of application: geopolymer coatings can be applied to both new and old concrete assets, and at a wide range of humidity ranges. The final issue faced in ambient curing of geopolymer coatings on concrete was efflorescence. The samples in batch 2 of 2Ca(CO3)2·5H2O), dotted lines are quartz and dashed lines are mullite. Background has been removed as the main feature of interest is the crystalline salt. The data was smoothed using the moving average method with a span of 9.To further analyze this efflorescence, the samples with efflorescence crystals were analyzed using XRD, as described in 2O is mobile and at the surface of the coating can react with atmospheric CO2 to form Na2CO3 phases. In our case, the XRD analysis showed that the reaction product was gaylussite—Na2Ca(CO3)2·5H2O. This result suggests that Ca may have been dissolved from the concrete substrate or the CaO present in the ash, forming gaylussite at the geopolymer surface. However, the CaO content of the ash is low which is consistent with the lack of visible C-S-H formation in The results reflected the literature findings discussed in The X-ray diffraction (XRD) spectrum of the fly ash and of the geopolymer obtained from the fly ash were acquired using the method detailed in 2/g) values in the sample. They [2/g), mullite (32.7 cm2/g), gypsum (64.7 cm2/g), hematite (214.3 cm2/g) and magnetite (221.3 cm2/g). The outliers are the iron phases but they are also present in small quantities in the fly ash as shown by the XRF composition given in The identification of amorphous content in geopolymers is not trivial as no ‘pure’ X-ray amorphous phase is formed without the presence of crystalline minerals. Recent work by Scarlett and Madsen  has showle. They  worked ole. They  comparedCoating thickness: coatings with thickness < 1 mm showed no cracks, regardless of mixing times and RH levels between 50% and 95%. Coatings with higher thickness showed cracks, the extent of which was dependent on the mixing time;Mixing time: for our mix, the optimal mixing time was 1 h, to allow the main extent of geopolymerisation reactions to occur without loss of water or thermal stress, and to ensure that only few fly ash particles were unreacted. Optimizing mixing time can allow geopolymer coatings to overcome water loss induced cracking and to show a homogeneous surface without voids and bubbles.Age of concrete: the results showed that coating integrity did not depend on concrete age. This is an important consideration if geopolymer coatings and linings are to be applied to newly cast concrete structures, and not only to old structures which need repair.Efflorescence: for low-temperature, but humid curing conditions (above 70% RH), efflorescence was likely, as excess alkaline solution crystallized on the surface of the coating. Efflorescence was less likely for relative humidities at or below 50%.This work demonstrated that fly ash geopolymer coatings can be cured at room temperature without any additional grinding steps or additives, provided some conditions can be met on site. While ambient-cured coatings did take longer to cure, they were touch-dry within one day, and were strong enough to form a non-structural class R1 repair within 28 days. Accelerants  may be required if the application demands more rapid strength development. The main factors that affected coating integrity were related to the retention of water in the geopolymer during its prolonged curing at ambient temperatures. These were:The challenge of ambient-cured geopolymer coatings is by no means easy to solve, due to the several competing and interconnected reactions and water transport processes: as the geopolymer cures, more N-A-S-H gel is produced, thus resulting in smaller pores, and in some cases in closed pores, and this will change the permeability of the geopolymer and so the water transport inside the geopolymer coating .Coating thickness was found to play a role in coating integrity. The thickness of cementitious coatings on concrete assets can play a direct role on their overall performance for their intended use. Firstly, repairs require high strain capacity to resist strain, and subsequently, cracks . ThickerThe thickness of patches has also been reported to affect the sensing capabilities of cement-based self-sensing coatings for loading applications. Baeza et al. reported that thinner patches had higher sensing capacity , whereasMorgan  has stat2/Al2O3 depends on how much aluminosilicate precursor has reacted and on the final product, since a link has been demonstrated between precursor type characterization and extent of the reaction [2/Al2O3 molar ratio of the final geopolymer, a detailed characterization of the geopolymer sample after curing is required, as described in [The actual compositional ratio SiOreaction . In orderibed in . It is bThis paper has outlined the manufacture of ambient-cured geopolymer coatings for concrete, without the use of additives. The most important consideration was the interaction between water-transport processes and the geopolymerisation reaction processes responsible for strength gain. While the geopolymer coatings took longer to cure than a thermally cured specimen, they remain a promising choice for retrofitted concrete repairs, rehabilitation and sensing. Future work should focus on solutions to the issues of efflorescence in humid environments, the influence of concrete substrate water saturation, durability under exposure to a variety of environmental conditions and should define methods for studying the relationship between coating thickness, shrinkage and integrity after prolonged geopolymer mixing.


Outpatient antibiotic use in Belgium is among the highest in Europe. The most common reason for an encounter in out-of-hours (OOH) primary care is an infection. In this study, we assessed all consultations from July 2016 to June 2018 at five OOH services. We described antibiotic prescribing by diagnosis, calculated disease-specific antibiotic prescribing quality indicators’ (APQI) values and critically appraised these APQI. We determined that 111,600 encounters resulted in 26,436 (23.7%) antibiotic prescriptions. The APQI diagnoses  covered 14,927 (56.7%) antibiotic prescriptions. Erysipelas (1344 (5.1%)) and teeth/gum disease (982 (3.7%)) covered more prescriptions than sinusitis or pneumonia. Over 75% of patients with tonsillitis and over 50% with bronchitis, sinusitis, and otitis media were prescribed an antibiotic. Only for otitis media the choice of antibiotic was near the acceptable range. Over 10% of patients with bronchitis or pneumonia and over 25% of female patients with an acute cystitis received quinolones. The APQI cover the diagnoses for only 57% of all antibiotic prescriptions. As 5.1% and 3.7% of antibiotic prescriptions are made for erysipelas and teeth/gum disease, respectively, we propose to add these indications when assessing antibiotic prescribing quality in OOH primary care. Antibiotic use in Belgium is among the highest in Europe, especially in ambulatory care, and thus the risk for antimicrobial resistance is high . The EurOut-of-hours (OOH) care covers a large part of hours during a week. In Belgium, but also in the rest of Europe, the on-going establishment of large-scale general practitioner cooperatives (GPCs) represents one of the most important developments for primary OOH health care. The most common reason for an encounter in Flemish (Northern part of Belgium) OOH primary care is an infection . Many inTherefore, the objective of this study is to assess the quality of antibiotic prescribing in OOH primary care to inform the implementation of future interventions to improve the antibiotic prescribing quality in this specific setting . More spData were extracted from the Improving Care and Research Electronic Data Trust Antwerp (iCAREdata) database, a research database of linked data on OOH primary care ,18. On aiCAREdata currently covers nine GPCs, that cover a population of 1,127,153. Only data from five GPCs were withheld for this study, because of the level of completeness of their data and availability at the start of the study. Together, they cover a population of around 811,000 inhabitants . The characteristics of these five GPCs are presented in Since the beginning of the year 2000, Belgian OOH care is increasingly being organized in GPCs in regions that typically cover 80–180 GPs. All practicing GPs in such an area are obliged to participate in this service following a rotation-based system of being ‘on call’ during the weekends in their own region and they work in shifts of on average 12 h. GPCs are mostly organized in a fee-for-service system. There are 80–180 GPs per GPC. Belgian GPs do not have a gatekeeper function. There is free access to primary, secondary, and tertiary care. They use an electronic medical health record to register every patient contact. The software can differ depending on the GPC, but diagnoses are always selected using Thesaurus terms in the Belgian Bilingual Biclassified Thesaurus (3BT). By selecting a diagnosis in 3BT, an International Classification of Primary Care (ICPC-2-R) code is automatically linked . PrescriData extraction was done using Microsoft SQL server 2012. We performed descriptive analyses using Microsoft Excel 2016. Data from 1 July 2016 until 30 June 2018 were included. To describe antibiotic prescribing by indication, first we only analyzed all antibiotic prescriptions  delivered during the consultations in five GPCs during a two-year timeframe and linked them with the diagnosis that was registered in the electronic medical health record. a = the percentage of patients with age and/or gender limitation (see legend Table 3) prescribed an antibiotic;b = a and receiving the guideline recommended antibiotic;c = a and receiving quinolones.Second, we used information on all encounters to assess the quality of antibiotic prescribing using the disease-specific APQI introduced by ESAC  in 2007 . The sevWe compared them with the findings of an earlier study with data from 2004–2009 from one GPC [We evaluated if APQI is a sufficient method when describing the quality of antibiotic prescribing in OOH care. We used and adapted the concept of drug utilization 90% (DU90%) , which aThe study was approved by the Ethics Committee of the Antwerp University Hospital/University of Antwerp (reference number 17/08/089), and registered at clinicaltrials.gov (NCT03082521). The study was approved by the scientific advisory board of ICAREdata and the different GPCs.From 1/7/2016 until 30/6/2018, 26,436 antibiotic prescriptions were registered in 111,600 visits (excluding home visits) covering a population of 811,097 persons. For 93.65% of the prescriptions, a diagnosis was registered in the same consultation. A diagnosis was missing for 1612 (6.35%) antibiotic prescriptions.For four conditions, the 5% upper limit of quinolone use was exceeded, i.e., in ascending order sinusitis (7%), bronchitis (11%), pneumonia (15%), and cystitis (25%). GPs can choose to enter a symptom diagnosis. , but only 3.8% of all antibiotic prescriptions are linked to this type of diagnosis .In 31,596/111,600 consultations, a diagnosis covered by APQI or erysipelas or dental abscess was made in OOH. Detailed diagnoses linked to antibiotic prescription are shown in Although most respiratory tract infections are self-limiting and usually caused by viral pathogens, at least half of the patients diagnosed with acute otitis media, sinusitis, tonsillitis, and bronchitis receive a prescription for an antibiotic at the GPC. Patients diagnosed with acute tonsillitis receive in 77% of the cases an antibiotic. Only for patients diagnosed with acute upper respiratory tract infection is the proportion of antibiotic prescriptions lower, but still higher than acceptable (30% while the acceptable range is between 0–20%). For nearly all indications the recommended type of antibiotics, according to the guidelines, are not prescribed apart from for otitis media, which is almost within the accepted range. Quinolone use is outside the acceptable range for following respiratory infections: sinusitis (7%), bronchitis (11%), and pneumonia (15%), which is in line with previous studies. The highest proportion of quinolones are still found among antibiotics prescribed for female patients with acute cystitis (25%). Looking at the total amount of antibiotic prescribing, we noticed a high number of prescriptions for erysipelas and dental problems, again with a high prescribing rate of non-guideline recommended antibiotics. There is not yet an acceptable range of prescribing determined for these two conditions. We suggest an acceptable range for the recommended antibiotic of more than 80% and respectively >80% and <30% of total antibiotic prescribing for erysipelas and teeth/gum disease.For acute tonsillitis and acute upper respiratory tract infection, the very low percentage of recommended antibiotics  can be explained by the frequent unavailability of small spectrum penicillin in the Belgian pharmacies, therefore GPs most often choose to prescribe amoxicillin as an alternative , and teeth/gum disease (ICPC D82), the latter most often representing a dental abscess based on notes review in a sample of the data. Therefore, we propose to add these two diagnoses (ICPC codes) when assessing the quality of antibiotic prescribing in OOH care. Further validation and more studies are necessary to confirm their relevance. However, when using these nine indications, only 66% of antibiotic prescriptions are covered and it could be argued that this is not enough to describe antibiotic quality. In accordance with the DU90%  concept,According to the Belgian antibiotic guidelines, the primary treatment of acute dental problems is dental care by a dentist . HoweverAPQI’s were calculated for 1 GPC from data from 2004 to 2009. In the current study, with five GPCs (including the one GPC that was used in the 2004–2009 APQI OOH study) we noticed similar results in the percentage of patients who received an antibiotic, but an improvement in choice of antibiotics. We have used electronic data that were routinely registered by GPs in their electronic health record for each patient contact. We used these observational routinely collected data retrospectively and GPs had no knowledge of an ongoing study. We included five GPCs  covering a large population that reflects the general population in Flanders (Belgium). Only GPCs with complete datasets were included. All GPs of the region are obliged to participate in the OOH care. Therefore, maximal coverage of GPs is guaranteed. In this way, we were able to achieve high validity and completeness of the data.The use of electronic primary care databases such as iCAREdata can produce valid APQI values . These vFeedback of APQI values could serve as benchmarks of (in)appropriate prescribing. Each GPC could compare their antibiotic prescribing quality with the range of acceptable use to help quantify the magnitude of inappropriate prescribing in OOH primary care. It gives the opportunity to focus on the specific challenges in every organization and to work on prescribing more accurately.These data could inform future tailored interventions to improve the quality of antibiotic prescribing in OOH primary care, such as we plan to do in the BAbAR project , and mayFlemish GPs too often prescribe antibiotics for self-limiting infections in OOH primary care and do not choose the guideline recommended antibiotics. When using disease-specific APQI to define the quality of antibiotic prescribing in OOH care, we suggest to calculate indicator values for two additional disease entities, since a substantial amount of antibiotics are also prescribed for dental abscess and erysipelas.


The thermal expansion coefficient and the microscopic thermal stresses of mature concrete depend on its microstructural composition and the internal relative humidity. This dependence is determined by means of thermoelastic multiscale analysis of concrete. The underlying multiscale model enables two types of scale transition. Firstly, bottom-up homogenization allows for the quantification of the thermal expansion coefficient and the elastic stiffness of concrete based on the Mori-Tanaka scheme. Secondly, top-down scale concentration gives access to the volume averaged stresses experienced by the cement paste, the fine and the coarse aggregates and, furthermore, to the stress states of the interfacial transition zones covering the aggregates. The proposed model is validated by comparing the predicted thermal expansion coefficient of concrete with independent sets of experimental measurements. Finally, sensitivity analyses are carried out to evaluate the influence of the volumetric composition and the internal relative humidity of concrete on the thermal expansion coefficient and the microscopic thermal stresses. The thermal expansion coefficient of mature concrete depends on the aggregate type, the volume fractions of the constituents, the age and the internal relative humidity . The typ RH=100% ,6. This  RH=100% ,9,10. Thum value . This deum value ,12. In tAs for quantification of the thermal expansion coefficient of concrete, empirical models, based on the rule of mixtures, have often been used ,5. Zhou Furthermore, microscopically inhomogeneous thermal deformations occur at temperature variations as a result of the heterogeneity of concrete. This leads to microscopic thermal stresses and to microcracking ,19,20,21In the present paper, a thermoelastic multiscale model is established to study the macroscopic thermal expansion and the microscopic thermal stresses of concrete in case of temperature changes. To this end, the cement paste, the fine aggregates, the coarse aggregates and the interfacial transition zones are introduced as elementary constituents of concrete. The scale transition from properties of microstructural compositions to macroscopic thermoelastic properties of concrete is carried out by means of the Mori-Tanaka scheme. As for the volume averaged microstresses of the cement paste and the aggregates, the contributions of the macroscopic strains and of the microscopic eigenstrains are considered. At a finer scale of observation, the continuity conditions of both the tractions and displacements across the interfaces, together with the generalized Hooke’s law of the material, give access to the microscopic stress states of the interfacial transition zones surrounding the aggregates.The paper is structured as follows: The thermoelastic multiscale model of concrete is described in ℓ. It satisfies the separation of scales principle [In continuum micromechanics a composite material is considered to be macro-homogeneous but micro-heterogeneous, occupying a representative volume element (RVE) with the characteristic size rinciple : (1)d≪ℓ≪d denotes the characteristic length of inhomogeneities within the RVE and  5 to 50 ,25,26.In general, the microstructure of RVEs of concrete are too complex to be resolved in full detail. Therefore, instead of it, quasi-homogeneous subdomains are introduced. They are referred to as material phases. The homogenized properties of the RVEs are governed by the properties of the material phases, their shapes, volume fractions and interactions .The hierarchical organization of concrete, consisting of cement paste, fine aggregates and coarse aggregates, is considered by means of two matrix-inclusion composites, introduced at two different scales of observation. Concrete is idealized as a continuous mortar matrix, hosting spherical coarse aggregate inclusions, see The Mori-Tanaka scheme is well-suited for such matrix-inclusion composites. It allows for the analytical homogenization of the thermoelastic properties of the composites. Each representative volume element (RVE), occupying the domain Isotropic elasticity is considered for both the matrix and the inclusion phases. Their elastic stiffness tensors The eigenstresses The volume fractions of the cement paste, the fine aggregates and the coarse aggregates are obtained from the initial composition of concrete asThe generalized Hooke’s law is used for the homogenized matrix-inclusion composite. It results inreads as 13)Chomtress as ,28(14)∑cheme as ,2915)Afined as 16)S=SvS=Sv(12)∑Afined asChomtressAs for quantifying the thermal expansion coefficient of the homogenized composite, Equation  yieldsαhomquations  and 21)αhom, thequations  and subsαhomquatiHomogenization of the concrete is carried out in two steps. Firstly, the matrix-inclusion composite of mortar in p on its the microstrain, reading as [q on the microstrain of phase p, reading as [The volume averaged microstresses of the matrix and the inclusions are quantified by top-down scale transition, based on knowledge of the macrostress tensor Equation  into EquEquation  and inseEquation . SubstitEquation  into EquEquation  allows fessed as ,3229)εading as 30)Dpp=ading as 31)Dpq=quations , the eigDpp=adingDpq=quatiEquation  into Equεading asThe volume averaged microstresses of the matrix and inclusion phases, Top-down computation of the microstresses with the help of the Equations –35) is  is 35) iporous cement paste covering the aggregates. They represent the weakest links in the microstructure of concrete [bulk cement paste. Thus, for estimation of the homogenized stiffness and the thermal expansion coefficient of concrete, they are idealized as two-dimensional interfaces. However, microscopic stress states of the ITZs are important for investigation of cracking and of the strength of concrete [Interfacial transition zones are thin layers of the concrete . Given tconcrete ,34. In oAssuming a firm bond between the aggregate inclusions and the surrounding ITZ shells, continuity conditions of both the tractions and displacements must be satisfied across the interfaces. Traction continuity results in the compatibility relation for the stresses of the inclusion, ce IiITZ 36)σi−σce IiITZ 37)t_1σaggEquation  as 41), baseVarious test results of the thermal expansion coefficients of mature cementitious materials are available in the open literature. They are significantly influenced by the test set-up. A relatively new test method, recommended by the American Association of State Highway and Transport Officials, AASHTO TP 60 , has becyi-Bekoe , Tasneemyi-Bekoe  and Naikyi-Bekoe  independk and the shear modulus E and Thermoelastic properties of the cement paste and of the aggregates are input for the proposed multiscale model. After mixing the cement clinker with water, the elastic modulus and the strength of the cement paste are growing fast in the first week and then are slowing down. Haecker et al.  measuredEquation  can be dThe elastic modulus, Poisson’s ratio and the thermal expansion coefficient of the aggregate depend on the mineral composition, the porosity, the crystal orientation and the texture of the aggregate rock ,5,39,40.(1)Experiments by Sakyi-BekoeSakyi-Bekoe  measuredAs for the model prediction, the thermoelastic properties of siliceous sand, granite, siliceous river gravel and dolomitic limestone were taken as the ones of quartzite, granite, sandstone and dolomite, from The model predicted thermal expansion coefficients of concretes with different initial compositions agree well with the experimental measurements, see (2)Experiments by Tasneem et al.Tasneem et al.  measuredAs for the model prediction, the thermoelastic properties of natural sand were taken as the ones of the sandstone. The input thermoelastic properties of the cement paste, the fine aggregates and the coarse aggregates are summarized in The model predicted thermal expansion coefficients of concretes with different initial compositions agree well with the experimental measurements, see (3)Experiments by Naik et al.Naik et al.  measuredAs for the model prediction, the thermoelastic properties of glacial gravel and natural sand were taken as the ones of sandstone. The input thermoelastic properties of the cement paste, the fine aggregates and the coarse aggregates are summarized in The model predicted thermal expansion coefficients of concretes with different types of coarse aggregates agree well with the experimental measurements, see The comparison of model predicted thermal expansion coefficients of concrete with experimentally measured values in The type and the volume fraction of the aggregates, as well as the internal relative humidity, are reported to have a significant influence on the thermal expansion coefficient of concrete ,13,14,37The thermal expansion coefficient of concrete, containing three different coarse aggregates, namely, sandstone, granite and limestone, respectively, with different volume fractions, is determined. The initial water-to-cement mass ratio The volume fraction of the cement paste is a constant, given as The computed values of the thermal expansion coefficient of concrete strongly depend on the type and the volume fraction of the coarse aggregates, see % to 50% , see theThe thermal expansion coefficient of concrete, containing three different coarse aggregates, namely, sandstone, granite and limestone, respectively, with different internal relative humidities, is determined. The initial water-to-cement mass ratio The thermoelastic properties of the fine and the coarse aggregates, as well as the elastic parameters of the cement paste, follow from The computed thermal expansion coefficient of concrete follows an unsymmetrical bell-shaped function of the internal relative humidity, see In order to study the influence of the volumetric composition and the internal relative humidity on the thermal microstresses, a concrete volume is considered to be subjected to a uniform temperature change Equation ,50)EhoEhoΔT, whEquation  and consEquation , deliverquation (εi=εi1=(AEquation  and consquation (εi=εi1=(Aquation (σi=σi1=3kquations –43), th, thΔT, wThey are independent of the zenith angle Statistic results of nanoindentation are considered for quantification of the elastic properties of the ITZ. Young’s modulus of the ITZ is considered to be around nt paste ,42. The nt paste  and, thuThe thermal microstresses of concrete, containing three different coarse aggregates, namely, sandstone, granite and limestone, respectively, with different volume fractions, are investigated. The initial water-to-cement mass ratio, Equation .Both the volume averaged microstresses within the cement paste and the microstresses of the ITZs surrounding the coarse aggregates strongly depend on the type of the coarse aggregates, see The thermal microstresses of concrete, containing three different coarse aggregates, namely, sandstone, granite and limestone, respectively, with different internal relative humidities, are investigated. The initial water-to-cement mass ratio is set equal to Equation . The theThe microscopic stresses in the cement paste and the ITZs surrounding the coarse aggregates strongly depend on the internal relative humidity. They follow the unsymmetrical bell-shaped functions, see A thermoelastic multiscale model of concrete with two types of scale transitions was presented. Bottom-up homogenization allows for quantification of the macroscopic thermal expansion and of the elastic stiffness of concrete, based on knowledge of the properties of its microstructural constituents. Conversely, top-down concentration gives access to the microstresses of the cement paste and the aggregates and furthermore, to the stress states of the interfacial transition zones covering the aggregates.The model predictions were compared with experimental measurements by Sayki-Bekoe , TasneemConcrete consisting of siliceous aggregates exhibits a larger thermal expansion coefficient and smaller microscopic thermal stresses, compared to concrete consisting of calcareous aggregates. Both the thermal expansion coefficient and the microstresses nearly depend linearly on the volume fraction of the coarse aggregates. This agrees with qualitative findings from experimental testing ,5,6,7.Concrete under partially-saturated conditions exhibits a larger thermal expansion coefficient and much larger microscopic thermal stresses, compared to concrete under fully-saturated and fully-dried conditions. This follows from the mismatch of the thermal expansion coefficients of the aggregates and the cement paste, which is an unsymmetrical bell-shaped function of the internal relative humidity.Temperature changes lead to microstructural stresses within concrete, even for macroscopically stress-free concrete volumes. The inhomogeneous thermal expansion coefficients of the constituents of concrete result in the incompatible thermal eigenstrain fields. The compatibility of the total strain fields requires microscopic mechanical strain fields.The thermal expansion coefficient of the cement paste is generally larger than that of the aggregates. In case of cooling, this leads to microscopic tensile stresses in the bulk cement paste and to compressive stresses in the aggregates and the surrounding ITZs. In case of heating, microscopic tensile stresses occur in the aggregates and the surrounding ITZs while compressive stresses occur in the bulk cement paste.The model provides quantitative insight into the sensitivity, regarding the thermal expansion coefficient and the thermal microstresses, of concrete with respect to the composition and the internal relative humidity of the material. This leads to the following conclusions:by using aggregates with large thermal expansion coefficients, which is, however, a trade-off between increasing the thermal expansion coefficient of concrete and decreasing the microscopic thermal stresses andby moistening the concrete, such that the thermal expansion coefficient of the cement paste decreases.Cracking of the cement paste, induced by tensile stresses, is a serious threat for the long-term durability of concrete structures. Both a decrease and an increase of the temperature can result in microscopic tensile stresses, either in the bulk cement paste or in the ITZs, that is, thin layers of porous cement paste surrounding the aggregates. In order to reduce the magnitudes of these tensile stresses, it is recommended to reduce the mismatch of the thermal expansion coefficients of the cement paste and of the aggregates. This can be achievedThe presented thermoelastic multiscale model for mature concrete is useful for the frequently encountered problem that the temperature changes rather quickly such that there is no significant interplay between thermal stresses and strains, on the one hand, and the viscoelastic behavior of concrete, drying and hydration of the material, on the other hand. In the future, the model will be extended to account for such couplings, which are particularly challenging at early material age. Because the chemical reaction between water and the cementitious binder is exothermal, initial hardening of concrete takes place at an increased temperature level. After the main peak of hydration is passed, the young concrete cools down. According to the coefficient of thermal expansion, cooling results in a reduction of the volume of concrete. This effect is amplified by autogenous shrinkage and eventually also by drying shrinkage. In reinforced concrete structures, the resulting overall shrinkage of concrete is constrained, resulting in tensile stresses. Creep of concrete reduces these stresses to some extent. Nevertheless, if they reach the tensile strength of concrete, early age cracking will occur. Mitigation of this problem is the topic of ongoing research ,44. Futueference .


P = 0.0130). In addition, c-MET expression is a candidate for targeted therapy in gastric cancer. Therefore, in the present study, the anti-cancer effects of the c-MET inhibitor on gastric cancer cells from positive or negative for c-MET amplification were evaluated.Gastric cancer is more open related to genetic predisposition. In our RNA sequencing study on gastric cancer patients, Runt-related transcription factor-3 (RUNX3) expression was significantly down-regulated in gastric cancer. We showed that decreased levels of RUNX3 are significantly associated with c-MET  cells. We also showed that INC280 inhibits the WNT signaling pathway and SNAIL expression in MKN45 cells. The data indicate that INC280 could be used as therapeutic agents for the prevention or treatment of diffuse gastric cancer positive for c-MET amplification.INC280 treatment inhibits growth of a c-MET-amplified MKN45 (RUNX3-positive) and SNU620 (RUNX3-negative) diffuse type cells. Then, INC280 showed the highest inhibition and apoptotic rates with the lowest ICThe online version of this article (10.1186/s13104-019-4163-x) contains supplementary material, which is available to authorized users. Helicobacter pylori infection and diffuse-type GC is more open related to genetic predisposition. Thus, diffuse-type is less related to environmental factors .To investigate the effect of the INC280 on c-MET amplified cell with or without RUNX3, c-MET and RUNX3 protein expression was evaluated in GC cells. c-MET and RUNX3 proteins were expressed in SNU5 and MKN45 cells. Interestingly, p-MET amplified gastric cancer cell lines belong to the diffuse-type Fig. b. We tesTo determine the inhibitory effects of INC280 on MKN28 and MKN45 cells, cell migration was examined by wound-healing assay using the respective IC50 values of INC280 (Additional file To evaluate the effects of INC280 on cell death in MKN28, SNU620, and MKN45 cells, apoptosis was examined by staining with annexin V-APC/PI, followed by flow cytometry (Additional file To examine the inhibitory effects of INC280 on MKN28 and MKN45 cells, oncogenic pathways were examined by analyzing gene and protein expression Fig. a–c. WhenCancer is a disease caused by genetic alterations. Therefore, we conducted RNA-seq in GC samples and their matched adjacent normal tissues to identify genetic alterations. The RNA-seq study showed that decreased levels of RUNX3 were significantly associated with c-MET, however cell lines were no correlated between RUNX3 and c-MET. RUNX3 loss is an early event in GC progression due to aberrant Wnt/β-catenin signaling –17, whicc-MET amplification is present in 2–20% of GC and is associated with a poor outcome , 21, 22.The results of this study indicate that c-MET and RUNX3 are differentially expressed in GCs compared with normal adjacent gastric mucosa and found a correlation between low RUNX3 levels and c-MET overexpression and tumor recurrence. INC280 shows significant inhibitory activity in c-MET-expressed diffuse GC. Our in vitro study strongly supports the clinical evaluation of INC280, which prevents c-MET-associated GC.Our study reports an association between MET and diffuse-type. However, the lack of significance in our study could be due to relatively small sample size. Although diffuse GC positive for c-MET amplification might serve as a predictor for poor outcome, it is considered as actionable target.Additional file 1: Table S1. Association of MET and RUNX3 expression with clinicopathological characteristics in 34 gastric cancer patients. Table S2. List of oligonucleotides for real-time PCR. Table S3. List of antibodies and its characteristic.Additional file 2: Figure S1. Wound-healing assay was used to assess the effect of INC280 on the migration ability of MKN28 and MKN45 cells. INC280-treated MKN45 cells showed suppressed migration ability compared with INC280-treated MKN28 cell lines. Figure S2. Effect of INC280 on cell death in MKN28, SNU620, and MKN45 cells. Flow cytometric analysis of INC280-induced apoptosis in A: MKN28 and MKN45, B: SNU620 cells. PI, propidium iodide.


This study investigated the impact of the location of a carbon fibre coated reinforcement ring (CFCRr) inside the structure of high-performance self-compacting fibre-reinforced concrete (HPSCFRC). Nowadays, cement matrix is considered as an alternative binder when reinforcing concrete structures with composite materials. Due to the plastic behavior of composite structures at relatively low temperatures when carbon fibres are reinforced with epoxy resin, the author attempted to locate carbon fibres inside a concrete structure. Thanks to this, the reinforcement will be less vulnerable to high temperatures (during a fire) and more compatible with concrete. The fibres act as a perimeter reinforcement that is compatible with the concrete mixture. The position of the CFCRr in the structure of concrete has an influence on the load capacity, stiffness and stress-strain behavior of concrete elements. The research was conducted on circular shape short concrete columns and tested under axial compression. The results demonstrated that by including CFCRr inside a concrete specimen, the maximum compressive strength decreases with an increase in the number of composite rings and a greater distance from the vertical axis of symmetry to the edge of the element. It has been proven in these studies that carbon fibres do not have good adhesive properties between CFCRr and a concrete mixture. As a result of this phenomenon, a shear surface is created, which leads to crack propagation along the CFCRr. Therefore, the presented idea of an internal CFCRr should not be used when designing new concrete structures.  When reaching this temperature, an element becomes more elastic and ductile , was ensured during the compression test. The axial and transverse  displacement was measured using extensometers. All the tested specimens and the test setup illustrating the Linear Variable Differential Transformer (LVDT) applications are shown in The specimens were tested under uniaxial compression using a 6000-kN capacity testing machine . All examinations were performed in a local laboratory at an air temperature of 25 ± 1 °C and humidity of 55 ± 5%. The constant axial strain rate, equal to 4 × 10The mechanical behavior of the HPSCFRC with the CFCR rings is presented using stress-strain curves. These relationships are shown in In the case of the concrete with one 60 mm CFCR ring inside, a similar stress-strain to the HPSCFRC was observed. The average maximum strength of the C60 was determined at a level of 78.62 MPa, which is nearly 3% lower than the HPSCFRC. This is also within the limits of 5% for statistical error. The main difference concerns the standard deviation, in the case of the C60 it is equal to 6.47 MPa. In reference to the average axial and transverse strains, the results are almost identical to the HPSCFRC. However, the only difference is the behavior of the C60 after exceeding the maximum compressive stress. The stress-strain characteristic is also brittle-plastic in this case, but more fragile than in the case of the HPSCFRC. The C110 group of specimens is characterized by a significant standard deviation of average compressive strength, which is equal to 15.31 MPa. In this case, a 15.66% lower compressive strength was observed. After reaching the maximum load capacity, a steeping loss of stiffness was noted. By using two CFCR rings with a 60 and 110 mm diameter, the average compressive strength has the lowest value. In the case of C60-110 specimens, the maximum standard deviation, average axial and transverse strains were noted. The stress-strain characteristics are different within the same type of samples. The behavior of the two samples is linear-elastic before maximum compressive stresses are obtained, plastic until the average axial strain is equal to 0.008, and fragile-plastic after exceeding this value. For these two samples, the maximum bearing capacity does not exceed the value of 50 MPa. These characteristics are different to the other two specimens, which are similar to the C60 group. During the forming of concrete structures, and especially in thin elements, the wall effect could be observed . This phThe typical representative failure modes of the specimens with CFCR rings are presented in In order to better explain the phenomenon of the impact of CFCR rings on the stress-strain capacity of HPSCFRC, determination of its behavior during the destruction of concrete reinforced with outer CF sheets using cement matrix could be useful. When using CFCR rings, the loss of the bearing capacity of concrete elements can be observed. With an increase in both the number of CFCR layers and the distance from the center of gravity of the specimens, the compressive strength decreases. In the case of using two rings inside the structure of the concrete, a 23% loss of compressive strength was observed.No cooperation between the CFCR rings and concrete was observed. The outer surface of the CFCR ring could be treated as the shear surface, which does not allow cooperation between the HPSCFRC and the CFRC rings. Cracks appear on the surface of the CFCR rings and then propagate to the external edges of the specimen, which in turn leads to their destruction.Usage of CFCR rings inside the structure of HPSCFRC is not justified due to the executive difficulties and stress-strain behavior for each analyzed configuration.The efficiency of reinforced HPSCFRC using outer CF sheets with cement matrix is not as sufficient as could be expected. Due to the observed low adhesion between the composite reinforcement and concrete in the ‘C150’ type specimens, it is not recommended to reinforce this type of concrete with CF sheets using infusible cement matrix.In the article, the influence of carbon fibre coated reinforcement rings on the behavior of high-performance self-compacting fibre-reinforced concrete was analyzed. Based on the experimental results, the following conclusions could be drawn:For future research, particular microanalysis concerning the contact between CFRP and HPSCFRC, as well as numerical simulations, will be performed. This knowledge will allow for crucial aspects occurring in the internal structure of these types of elements to be determined. Moreover, the influence of the type of concrete surface  on the properties of HPSCFRC reinforced with CF sheets using epoxy resin and cement matrix were performed, and will be published soon.


To address this gap we analyzed public metagenomic datasets from 24 antibiotic treated subjects and controls, combined with an in-depth prospective functional study with two subjects investigating the bacterial community dynamics based on cultivation-dependent and independent methods. We observed that short-term antibiotic treatment shifted and diversified the resistome composition, increased the average copy number of antibiotic resistance genes, and altered the dominant strain genotypes in an individual-specific manner. More than 30% of the resistance genes underwent strong differentiation at the single nucleotide level during antibiotic treatment. We found that the increased potential for horizontal gene transfer, due to antibiotic administration, was ∼3-fold stronger in the differentiated resistance genes than the non-differentiated ones. This study highlights how antibiotic treatment has individualized impacts on the resistome and strain level composition, and drives the adaptive evolution of the gut microbiota.Despite the documented antibiotic-induced disruption of the gut microbiota, the impact of antibiotic intake on strain-level dynamics,  The human intestines are densely populated by diverse microbial inhabitants, which collectively constitute the gut microbiota. About 1000 prevalent bacterial species colonize the human gastrointestinal tract, playing a pivotal role in health and disease of the host. Besides influencing physiology of the digestive tract, the gut microbiota also affects development, immunity, and metabolism of the host Antibiotics have been widely used since the Second World War resulting in dramatic benefits to public health de novo evolution) or horizontal gene transfer (HGT) De novo resistance mutations can modify the antibiotic cellular targets or alter the expression of antibiotic resistance genes and therefore alter the resistance levels of the bacterial strain harboring them de novo resistance mutations, horizontal gene transfer allows bacteria to adapt more rapidly to an environment containing antibiotics Enterococcus faecium and Escherichia coli, respectively in situ HGT of ARGs in the infant gut was described Antibiotic resistance can be acquired through point mutations .We next studied whether antibiotic treatment could select similar sets of antibiotic resistance genes and converge the resistome composition across individuals. If the gut resistome presents a more common response, instead of an individualized response, to an antibiotic treatment, we would expect the resistome compositions to become more similar after the treatment across individuals. We found that the dissimilarity of the ARGs composition measured by the Jaccard distance between individuals increased significantly over time in the antibiotic treated group  could be altered during treatment. Incorporating the reference genomes of the 28 most prevalent species  based on the shotgun metagenomic data of 72 samples from 24 individuals revealed that there is a significantly higher proportion of differentiated sites (see Methods for definition) in the treated subjects than the control group , suggesting that intraspecies level selection tended to influence the functional potential of the ARGs within the population of each bacterial species.To evaluate the potential functional influence of the differentiated sites in the treated subjects, we investigated the frequency of differentiation at either non-synonymous sites (0-fold degenerate sites) or synonymous sites (4-fold degenerate sites). Compared with all the sites in the coding region, single nucleotide differentiation is drastically enriched at non-synonymous sites , while the HGT potential in differentiated ARGs increased more drastically and significantly than in the non-differentiated ones  for a particular gene is associated with two factors, the intrinsic HGT tendency of the gene and its prevalence in the population. Therefore, we estimated the HGT potential for the ARG families by combining the relative abundance and the HGT rate P = 0.038, We discovered a significantly positive correlation between community-level fold-change of the HGT potential and the average rate of differentiated sites in the ARGs . Our results reveal that the 28 dominant strains of the treated subjects present significantly closer phylogenetic relationships between samples from the same individual than the samples across individuals  a drastically decreased  genome-wide nucleotide diversity  on the β-lactam plates during cefuroxime treatment (day 5)  during treatment in the cefuroxime-treated subject  . Even th subject B–C, sugg subject C.Figure P < 0.01, Wilcoxon rank-sum test) on β-lactam plates than on the non-β-lactam plates  over time .To evaluate the variation in taxonomic composition of cultured resistant bacteria in both cefuroxime-treated and control subjects at different time points, we performed 16S rRNA sequencing of the colonies grown on different antibiotic containing plates. We observed that the community dissimilarity (beta-diversity), measured by the Morisita–Horn index, between antibiotic plates from the treated subject decreased after the cefuroxime treatment. This converging pattern of resistant communities among different antibiotic plates was not observed in the control subject D and S5.m plates D and S6.ver time E. Such sP < 0.05 using permutation test) from all β-lactam plates in the cefuroxime-treated subject  on β-lactam plates between baseline (day 0) and treatment (day 5) samples, we identified 12 species with significantly increased phenotypic resistance during treatment  in different species with metagenomic analysis of the cefuroxime treated and control subjects  the recovered genes A–B durinE. coli and E. faecium revealed a strong selective force imposed by antibiotic treatment at the intraspecies level, we subsequently investigated further how the functional ARGs diversified within the population of each species during the cefuroxime treatment. The analysis of SNV, combining functional and shotgun metagenomics data, revealed that the 114 functionally selected ARGs contain a significantly higher proportion of differentiated sites in the cefuroxime-treated subject than in the control   during or after treatment (P < 0.01 with Wilcoxon signed-rank test) during treatment in the cefuroxime-treated subject (Since the genome-wide selective sweep in nk test) C. At thereatment C, consisreatment D. Furthe subject , consistvs. 42%)  of highly homologous hits (identity >95% at amino acid level) of the functional ARGs against the NR database using blast (see Methods). We explicitly defined recent HGT-related ARGs by considering the confidence level of LCA and the taxonomic information from NR hits (see Methods). This analysis indicates that there is a higher proportion of differentiated functionally selected ARGs involved in recent HGT events than in the non-differentiated ones (57% vs. 42%) D. To valvs. 42%) , suggestvs. 142%, P < 0.01 with Wilcoxon signed-rank test, The higher rate of recent HGTs in differentiated ARGs motivated us to investigate further whether these ARGs were associated with plasmid-mediated bacterial conjugation. We searched for all highly homologous hits (>95% identity) in the NCBI plasmid RefSeq database using the ARGs as queries. We found that about 33% of differentiated and 11% of non-differentiated ARGs have highly similar (>95% identity at amino acid level) plasmid hits D, supporIn this study, we observed antibiotic-induced strain-level dynamics, resistome diversification, and increased resistance dissemination potential within the human gut. The integrative approach deployed in this study enabled the elucidation of complex dynamics of the resistome and gut microbial strains during antibiotic treatment. We used computational analyses of existing metagenomic datasets to find evidence for antibiotic induced diversification of the resistome, as well as substantial treatment induced differentiation of antibiotic resistance genes. We further elucidated widespread strain level dynamics exacerbated by antibiotic treatment. Combining these results, we showed that the increased dissemination potential of antibiotic resistance gene is strongly associated with the frequency of the differentiated sites during antibiotic treatment. We then performed a functional survey in a prospective intervention study, enabling detailed culture-based and culture-independent characterization of the human gut resistome and resistance phenotypes. The consistent findings from two experimental designs reflect the generalization of our conclusions.E. coliPrevious studies have provided evidence that certain factors could influence the HGT potential in the human intestine. For instance, it has been shown that human intestinal epithelial cells produce proteinaceous compounds that modulate antibiotic resistance transfer via plasmid conjugation in E. coli and E. faecium highlights the influence of antibiotic treatment on the intraspecies level dynamics. In line with this, future antibiotic treatment should be more personalized regarding the dosage, duration, and combination of drugs based on the unique strains and resistome composition in each patient to minimize the unintended disruption of the gut microbiota. Unfortunately, how the initial gut microbiota composition relates to antibiotic treatment efficacy, side effects, long-term susceptibility to different pathogens, or diseases is poorly explored thus far. Therefore, more studies with longitudinal sampling and sequencing of the gut microbiota, evaluation of antibiotic efficacy, and surveillance of susceptibility for infections or other diseases are needed. Such data could uncover the microbiota-dependent antibiotic efficacy and side effects, the interaction networks between antibiotic and gut microbes, and long-term microbial dynamics, paving the way for future microbiome-based diagnosis and treatment.Due to the fact that the disturbed microbiota could lead to adverse health outcomes Although our strain-level analyses offer novel insights into the dynamics of the resistome composition, copy number variation, and single nucleotide level differentiation of ARGs upon antibiotic treatment, the scarcity of reference strain genomes for many species and the incompleteness of the ARG database as well as the non-robust annotation methods could potentially bias these quantifications to certain extent and limit the generalization of our conclusions. Another caveat is that although metadata, including gender, age, weight, etc., for each individual were provided in the original study of the public data, the sample size was not sufficient for further in-depth analyses regarding these potentially confounding factors. Future studies with more individuals, increased sampling density, and the development of more comprehensive ARGs databases and accurate annotation methodologies would be of great value.A total of 72 samples from 18 cefprozil treated subjects and 6 control subjects used in the study of Raymond et al. To functionally validate the findings of our computational analysis based on public metagenomic datasets, two healthy adult human female subjects  who had not taken any antibiotics for at least one year were selected for this study. One subject underwent a standard 5-day treatment with cefuroxime  while the other subject had no treatment, serving as a control. Eight fecal samples were collected longitudinally over a period of three months corresponding to pre-treatment (Day 0), two time points during treatment (Days 2 and 5), one week post-treatment (Day 12), two weeks post-treatment (Day 19), three weeks post-treatment (Day 26), one month post-treatment (Day 33), and three months post-treatment (Day 97). All participants consented to these experiments and sample collections and downstream experiments and data processing followed ethical guidelines  throughout the study. Samples were transported to an anaerobic chamber within an hour of collection. Five grams were separated out for culturing  and 2.5 g were used for DNA extractions. The remaining stool samples were stored at −80 °C.The stool samples were cultivated with or without the presence of 16 antibiotics, followed by DNA extraction and sequencing of 16S rRNA as described previously e.g., all β-lactam plates) for each OTU were compared using a Wilcoxon signed-rank test The relative resistance level for each OTU is defined as the ratio of the relative abundance of the OTU from each antibiotic plate to the relative abundance of the same OTU in the control plate at each time point. To test whether certain OTUs had overall enhanced resistance over time, the resistance levels . ORFs were annotated by comparing the protein  or nucleotide  sequences to known sequences in several databases with 80% identity and coverage. Sequence reads were removed from the annotation list if no match to known or suspected antibiotic resistance genes could be found. Forward and reverse reads from the same sequence that overlapped along the same resistance gene(s) were merged into a single annotation.All DNA fragments from 1056 functional clones were sequenced using Sanger sequencing, imported into CLC Main Workbench where the cloning vector sequence was removed and reads of poor quality were discarded. Assembly of reads from all samples was attempted simultaneously in order to simplify the final output and identify sequences sharing the same sequence. All assembled contigs were hand checked for errors and correct alignment. A total of 197 contigs consisting of 2 or more sequences and 104 unassembled single sequences were retrieved. Open reading frames (ORFs) were annotated using ORFinder  first. The latest common ancestor (LCA) at species level based on highly homologous (identity >95%) hits for each ARG was deduced using MEGAN A total of 154,805 gene families were retrieved from the HGTree database Culture-independent fecal extracts from treated subject samples Day 0, Day 2, Day 5, Day 12, Day 19, Day 26, Day 33, and Day 97 and control subject samples Day 0, Day 2, Day 19, and Day 97 were used to build shotgun metagenomic libraries using the Nextera XT kit with the standard protocol. The HiSeq 1500 was used for 100 bp PE sequencing in the CGS of The University of Hong Kong and the average throughput for each sample was 10.5 Gbp. The raw sequences can be found in BGID (CRA000815).To retrieve the high quality reads for downstream analyses, we used a series of quality control steps to remove the low quality reads/bases as described previously The Metagenomic Intra-Species Diversity Analysis System (MIDAS) i, the HGT potential (iHGTP) is defined as,iH is the aforementioned HGT rate in this gene family i and iA is the relative abundance of this gene in the sample.For a single gene n genes, the overall HGT potential is defined as,For a set of According to formula P values were adjusted to false discovery rate (FDR) using Benjamin’s method To identify the potential adaptively evolved variant sites in the genes, we calculated the difference of the allele frequency spectrum, which was extracted from the variants calling using MIDAS mentioned above, using Fisher’s exact test between treatment and baseline samples at each single nucleotide variant site. For example, the A:T ratio for a particular variant site in one ARG is 1:9 initially but was altered to 7:3 during the treatment, indicating potentially adaptive evolution where the allele frequency distribution has been differentiated. To correct for the influence of sequence depth on the statistical power, the maximum depth for each site was down-sampled a maximum of 10 before Fisher’s exact test was carried out. The raw The enhanced overall resistance level in the culture-dependent plates and the species with enriched resistance across multiple plates were analyzed using the Wilcoxon signed-rank test MOAS, EAR, and GP designed this study. EAR performed the experiments. JL, EAR, ME, and EVDH analyzed the data. JL and EAR drafted the manuscript. All authors commented on and revised the manuscript.All authors declare no conflict of interest.


Novel polyhedral oligomeric silsesquioxanes (POSS)-filled thermoplastic electrospun veils were used to tailor the properties of the interlaminar region of epoxy-based composites. The veils were designed to be soluble upon curing in the epoxy matrix, so that POSS could be released within the interlaminar region. Three different POSS contents, varying from 1 to 10 wt %, were tested while the percentage of coPolyethersulphone (coPES) dissolved in the epoxy resin was kept to a fixed value of 10 wt %. Good quality veils could be obtained at up to 10 wt % of POSS addition, with the nanofibers’ diameters varying from 861 nm for the coPES to 428 nm upon POSS addition. The feasibility of the soluble veils to disperse POSS in the interlaminar region was proved, and the effect of POSS on phase morphology and viscoelastic properties studied. POSS was demonstrated to significantly affect the morphology and viscoelastic properties of epoxy composites, especially for the percentages 1% and 5%, which enabled the composites to avoid POSS segregates occurring. A dynamic mechanical analysis showed a significant improvement to the storage modulus, and a shift of more than 30 °C due to the POSS cages hindering the motion of the molecular chains and network junctions. Thermosets are widely used in polymer matrix-reinforced composites because of their easy processing and good mechanical properties. However, the inherent brittleness of thermosets led to the development of different toughening strategies. Among the most recent toughening approaches, the use of electrospun veils is particularly advantageous.Some authors have focused on non-soluble electrospun fibers based on the use of Nylon fibers. Akangah et al.  showed tOther authors have proposed a different approach, based on the use of soluble veils that dissolve under resin curing and phase separately, generating specific phase morphology. Li et al.  showed tRecently, electrospun fibers that can be used to selectively disperse carbon nanotubes in the interlaminar region upon veil dissolution were reported . Cicala 1/2 for the unmodified resin to 0.80 MPa·m1/2 by adding 1% of multiwall carbon nanotubes functionalized with amine groups. Chul Kim et al. [Nanofillers have shown their efficiencies for the toughening of epoxy resin, too. Gojny et al.  studied m et al.  reportedm et al. . In situm et al. .Tg) [Among the different nanofillers that can be added to epoxy resins for tailoring their properties, polyhedral oligomeric silsesquioxanes (POSSs) are of high interest. POSSs are of interest as they can combine a hybrid inorganic–organic composition with nanosized silica-like cage structures. In addition to that, their dimensions are comparable to those of most polymeric segment or coil, and they can be bound to polymer chains. These properties allow POSS to reinforce systems at the molecular level. Finally, as for other nanoparticles, the large surface area allows the use of only small amounts to cause significant changes in the properties of the matrix . In seveTg) ,16, fireTg) , resistaTg) , and eleTg)  reportedTg increases for epoxy resins [Tg with increasing POSS content is also reported [Tg by increasing free volume and reducing interaction between polymer chains. This result contrasted with other findings, but it must be observed that the amino-propylisobutyl POSS used by Frank et al. had a long aliphatic chain, which might have affected the result.The effect of POSS on the viscoelastic properties of an epoxy network is discussed in the literature. Lee and Lichtenhan  observedy resins . Howeverreported . Frank ereported  investigSome authors have reported the addition of POSS to electrospun fibers , but to Here, we report for the first time the use of POSS-filled electrospun soluble veils for the delivery of POSS into the interlaminar region of advanced composites manufactured by resin infusion. The proof of the concept is achieved combining both miscroscopic and spectroscopic techniques. In addition to that, the effect of POSS on the viscoelastic properties of the composites are discussed.The epoxy resin used was diglycidyl ether of bisphenol A (DGEBA) supplied by Shell Chemical, Akron, OH, USA. The curing agent was 4,4′-methylene bis (MDEA) supplied by Lonza, Basel, Switzerland. The thermoplastic polymer was a coPolyethersulfone, synthetized by the authors, with an average molar mass of 9000 g/mol (coPES9k). The details regarding the synthesis and characterization of coPESs are discussed elsewhere ,25,26. P3)4 [4H9)7–Si7O9(OH)3 was prepared according to methods described in the literature [4-chlorophenyl hepta isobutyl–POSS was synthesized by the Corner Capping Reaction of isobutyltrisilanol with the suitable 4-chlorophenyltrimethoxysilane, which was prepared from the appropriate Grignard reagent and Si(OCH3)4 ,28. The terature . TetrahyIsobutyltrisilanol  was dissolved in 50 mL of ethanol and 4-chlorophenyltrimethoxysilane  and 2.0 mL of tetramethylammonium hydroxide were added under stirring. The solution was mixed by stirring at room temperature for 24 h. The resulting solid was then filtered and washed with 10 mL of anhydrous ethanol. Drying under reduced pressure was then performed, and the white solid obtained was crystallized from a THF/MeCN mixture to obtain 3.60 g of the desired compound (77.7% yield). The chemical structure of the synthetized POSS is reported in N,N-dimethylformamide (DMF) and 5.00 mL of toluene). The solution obtained was mixed for 2 h at 40 °C. This solution was positioned in a 3 mL medical syringe. The processing parameters to electrospin the coPES veils were as follows: flow rate of 60 µL/min, voltage of 21 kV ddp, and a needle–collector gap of 10 cm. The collector used was a rotating drum (200 rpm) covered with antistatic paper. Electrospinning was carried out on an EC-DIG electrospinning apparatus purchased from IME Technologies, Geldrop, The Netherlands.The coPolyethersulphone (coPES) veils were prepared by dissolving the coPES (5.00 g) powder in a solvent mixture  were prepared. The starting solution, for all of the three cases, was that one of coPES prepared by using the same procedure described above. When the polymer was completely solubilized, POSS powder (in the three different percentages) was added into the solution and uniformly dispersed by using the ultrasaunder UP 200 Ht by Hielscher, Teltow, Germany. After 1 h, the three solutions were electrospun with the same conditions used for coPES.Six layers of dry carbon fabrics with electrospun veils were laid down on a flat steel plate. The proper sealing was ensured by placing an adhesive silicone tape around the perimeter of the layered stack. A flexible vacuum bag was placed on top of the assembly. An inlet tube and an outlet tube were placed inside the vacuum bag. The vacuum was applied, through a valve, while the inlet valve was closed to compact the layers and to remove excess air. After the proper fabric degassing was ensured, the stacked layers were placed in an oven preheated to 130 °C. The epoxy resin was then vacuum infused into the stacked layers. The temperature was kept at 130 °C for 30 min, and then increased by 2 °C/min up to 180 °C and held at that value for 3 h. Considering the weight of the carbon fabric , the correct amount of coPES veil was laid in the interlaminar regions to obtain 10 wt % of the toughener in the final laminate.A hot-stage microscopy analysis was carried out to monitor the dissolution of coPES veils in the epoxy resin formulation at different temperatures. The Linkam THMS 600 hot-stage with a TP-90 controller  was fitted to an Olympus BX60 optical microscope . The unmodified epoxy resin  was preheated to the testing temperature. After that, a single drop of resin was laid down on a thin glass microscope slide. The coPES veil was then placed on top of the resin droplet, after which another thin glass slide was placed on top of the veil wetted by the resin droplet. The specimen was held in the hot-stage at the testing temperature for the time needed to observe the complete dissolution of the veil. This procedure was carried out for testing temperatures of 80, 90, 100, 110, 120, and 130 °C.3. The tests were carried out at 1 Hz with a 2 °C/min heating rate ranging from −100 to 130 °C, using liquid nitrogen for sub-ambient scans.The viscoelastic behavior of the materials was investigated using a DMTA device  by single cantilever geometry and using samples of size (20 × 10 × 3) mmMicrographs were obtained by using a SEM: Zeiss EVO, Cambridge (UK). SEM analysis was carried out on the electrospun veils and on the cured laminates. The electrospun veils were gold sputtered before the analysis without any other pre-treatment. The diameter of the nanofibers was determined from the SEM images with the software Fibraquant. The interlaminar regions of the composite laminates were examined by SEM after polishing before etching. In one case, a crio-fractured surface was also analyzed for comparison purposes. An acid mixture was used to etch the epoxy phase. The effect of the etching procedure was to increase the contrast between the thermoplastic and epoxy phases. The etching treatment was carried out by the immersion of the samples in the acid mixture, followed by a stirring time of 20 min. The samples were always washed with water after etching, and were then sputtered with gold. The etching time did not alter the phase morphology .−3 g, put in open alumina crucibles, were degraded in dynamic heating conditions (10 °C·min−1) in the temperature range of 25–800 °C in flowing nitrogen (0.02 L·min−1), and their weights were measured as a function of temperature. The error in the mass determination due to the reduction of the buoyancy force on increasing temperature [D)%, as a function of temperature, where D = (Wo − W)/Wo, and Wo and W are the weights at the starting point and during scanning, respectively.The thermal degradations of the studied composites were carried out in a Thermogravimetric Analyzer TGA 1 Star System . Samples of about 5 × 10perature  was corrThe morphology of the electrospun veils with different POSS contents is shown, at low magnification, in For the 0 wt % and the 1 wt % POSS veils, the electrospun fibers appear uniform and with very few beads. When the POSS content increased to 5 and 10 wt %, more beads in the micrometer range appeared. By increasing the POSS loading in the PES, large agglomerates tend to crystallize by themselves, since a uniform dispersion of POSS is achieved by limiting the relative percentage . In factAn EDX analysis confirmed a high Si content in the composite nanofibers upon increasing the POSS loading from 1 to 10 wt % .It is noteworthy that the chlorine presence in the POSS structure is detectable, by EDX, in the sample containing the high percentage of POSS.More evidence of the presence of crystallised agglomerates of POSS in the PES veils is provided by the XRD analysis. The diffraction spectrum reported in The average fiber diameters for the electrospun veils were calculated by the SEM images with the image software analysis Fibraquant, which has been specifically developed for the analysis of electrospun fibers. The software allows for the exclusion of the beads from the calculation. An example of the distribution graph for the average fiber diameters in the case of the coPES veils is shown in The decrease of the coPES/POSS nanofiber diameters could be explained by considering that the silsesquioxane molecules, containing Si atoms, increased the conductivity of the solutions. Increasing the solution’s conductivity is known to result in thinner fibers, because the increased charge carrying capacity of the jet results in higher tension on the jet with the applied electric field . SimilarHot-stage microscopy was used to evaluate the dissolution rate in the uncured epoxy matrix of the electrospun veils at different temperatures. This is a first test used to assess the behavior upon the curing of the soluble veils. The time required to obtain the full dissolution of the veils is summarized in The graph shows that increasing the POSS content resulted in a delayed time for the veil’s full dissolution. Similar results were found previously for higher molar mass coPES . The epoThe interlaminar region of the cured laminate was analyzed by SEM to monitor the dissolution and phase separation of the coPES nanofibers. The interlaminar region of the sample with 10 wt % of coPES/1% POSS showed distinctive features with respect to that with a coPES veil . In thisA higher resolution SEM coupled with EDX analysis was performed on the same sample. The analysis at a magnification of 80,000× revealed the presence of nanoscaled POSS crystallites .An EDX analysis has been performed in three of the interlaminar regions characterized, respectively, by uniform resin morphology , zone 1,The laminates prepared by adding 10 wt % of the veil coPES/5% POSS  and coPEWhen the coPES/10% POSS veil was used, a dominant particulate morphology a and somThe analysis of all the laminates with coPES/POSS veils revealed i.e.,  the presThe morphological differences observed in the interlaminar region for the samples with coPES/POSS veils, if coupled with the delayed dissolution times i.e., , revealeE’). The increase of the storage modulus was the result of the reinforcing effect of the POSS cages. As explained by Lee and Lichtenhan [The viscoelastic properties of the POSS epoxies were measured by DMA . DMA is chtenhan , the prechtenhan .The tan δ curves showed a different behavior compared to the sample with the unfilled coPES veils. The addition of POSS resulted in the lowering of the amplitude of the tan δ peak for all POSS percentages. In addition to that, two tan δ were not evident in those samples. The sample with the veil coPES/1% POSS showed a broad single peak spanning from 100 to 200 °C. The sample with the veil coPES/5% POSS showed a sharper single peak centered at 210 °C, while when the POSS content increased to 10%, a main peak at 140 °C appeared with a shoulder at about 174 °C. In accordance with the findings of the morphological analyses, the DMA results confirmed that the addition of POSS interacted with the dissolution/phase separation behavior of the coPES nanofibers.The composites used in this study were highly complex, due to the simultaneous presence of the coPES dissolution and phase separation phenomena. The formulation with a higher percentage of POSS segregates  to evaluate the resistance to thermal degradation  were slightly lower than that of PES (480 °C), thus indicating that the dispersion of nanoparticles in the polymer matrix does not compromise significantly the thermal stability of the obtained composites.The thermal behaviour of the composites was investigated, together with that of the pristine PES, which was also studied for comparison. The aim was to determine if, and if so, and by how much the resistance to the thermal degradation is affected by the introduction into the polymer matrices of different percentages of nanoscale POSS molecules. Both the PES and composites degraded in a well-defined single stage, thus leading us to select the initial decomposition temperature (radation . The Ti he curve . The TG The purpose of the present paper was to evaluate the feasibility of soluble thermoplastic veils as a means to disperse, in the interlaminar region of composite, POSS fillers without adding them to the neat resin.The morphological analysis carried out on the electrospun veils demonstrated that electrospinning is an efficient technique to obtain thermoplastic veils with a high content of POSS dispersed both at the nano and microscale.The analysis on the cured laminates confirmed the full dissolution of the coPES nanofibers within the processing ranges used, and, of foremost importance, proved that nanofillers can be effectively dispersed by using the soluble thermoplastic veils. The addition of POSS showed to have a significant effect on the final interlaminar morphology, and, in turn, on the viscoelastic properties of the laminates. The veils filled with 5% of POSS showed the best improvement in terms of glass transition temperature because of the synergetic effect of morphology control and POSS dispersion level.The results achieved in this paper could be further expanded by filling the coPES veils with different types of nanofillers, such as carbon nanotubes or nanoclay. The use of filled thermoplastic veils is a promising approach to develop laminates with multiple layers of different types of nanofillers in a single processing step.


TGA curves indicated that the cured copolymers also exhibit excellent thermal stabilities.Phenol-diaminodiphenylmethane-based benzoxazine (P-ddm)/phthalocyanine copolymer was prepared by using P-ddm resin as matrix and 3,10,17,24-tetra-aminoethoxy lead phthalocyanine (APbPc) as additive. Fourier-transform infrared (FTIR), differential scanning calorimetry (DSC), dynamic mechanical analysis (DMA), and thermogravimetric analysis (TGA) were used to investigate the curing behavior, curing kinetics, dynamic mechanical properties, thermal stability, and impact strength of the prepared copolymers. The kinetic parameters for the P-ddm/APbPc blend curing processes were examined by utilizing the iso-conversional, Flynn–Wall–Ozawa, and Málek methods. The P-ddm/APbPc blends exhibit two typical curing processes, and DSC results confirmed that the blending of APbPc monomer can effectively reduce the curing temperature of P-ddm resin. The autocatalytic models also described the non-isothermal curing reaction rate well, and the appropriate kinetic parameters of the curing process were obtained. The DMA and impact strength experiments proved that the blending of APbPc monomer can significantly improve the toughness and stiffness of P-ddm resin, the highest enhancements were observed on 25 wt.% addition of APbPc, the recorded values for the storage modulus and impact strength were 1003 MPa and 3.60 kJ/m However, polybenzoxazine still has shortcomings such as being cured at higher temperature, processing difficulty, and higher brittleness  units linked by four N atoms to form a conjugated macrocyclic chain, a number of Pc are modified in the center with various metal elements, including Cu, Zn, Pb, etc., and substituted in the periphery with various groups  versus ln[m/na(1 − a)] for 0.2 ≤ α ≤ 0.90 plot, respectively, results are already summarized in Furthermore, the Málek method was used to determine the suitable curing kinetic model and parameters. According to Equations (9)–(11), the experimental data and the average value of the activation energy, we can determine the data value of c system . By meandα/dt, is a function of the curing rates of reaction 1 and reaction 2 , according to Equation (15) [1 + 0.36α2 for P-ddm/APbPc system, which means dα/dt = 0.64dα1/dt + 0.36dα2/dt. The experimental results were compared with the model predictions, as shown in The overall heat is affiliated with the heat of reactions 1 and reaction 2. Therefore, the overall curing rate, ion (15) ,54. In t−2) was recorded for the 25 wt.% APbPc blended copolymer, which is almost 188% higher than recorded value for the neat poly(P-ddm) (1.91 ± 0.21 kJ·m−2). These distinctive improvements in the impact strength can be attributed to the flexible aminoethoxy group chain segment of APbPc, which disperses the applied impact load by the segmental movement of aminoethoxy group in the P-ddm/APbPc copolymer. Additionally, a similar cavity formed by a crosslinked matrix structure could absorb some applied energy during impact.The change in the impact strength values as a function of various wt.% of APbPc contents is shown in gT) with respect to increasing wt.% of APbPc in copolymer. The variations of storage modulus (G′) and damping factor (tan δ) against temperature are illustrated in G′ at 50 °C), gT (tan δ peak temperature), and crosslinking density calculated by the rubbery equation are summarized in Dynamic mechanical analysis of P-ddm/APbPc copolymers was carried out as a temperature function to ascertain the thermomechanical behavior of the copolymer and analyze changes in dynamic modulus and glass transition temperature  at 50 °C was recorded as 2675.9 MPa, and a rise of 1003 MPa was observed as for 25 wt.% containing APbPc copolymer, the recorded value was 3678.9 MPa. Here APbPc reacts with P-ddm, and forms a three-dimensional crosslinking structure. Moreover, APbPc is a conjugated macrocyclic compound with four substituted in the periphery with aminoethoxy groups. APbPc blending improves the crosslink densities of the copolymers, which enhances the capabilities of the storage energy as compared to neat resins [3.t resins . SimilargT of copolymers with different APbPc proportions can be obtained from tan δ transition peak. The addition of APbPc in the copolymer matrix leads to the decrease of gT, due to the flexible chain in APbPc, and which can have the chain segmental movement at relatively low temperature. The gT value of pure poly(P-ddm) was recorded at 217.6 °C, and gT value of 25 wt.% APbPc containing copolymer was recorded 24.6 °C lower (193.0 °C).The single tan δ transition peak was observed in all the studied copolymer compositions within 100 to 250 °C temperature range as shown in 5%T) and 10 wt.% (10%T) losses along with the percentage residual weight (cY) taken at 800 °C.The thermal decomposition of the copolymers was employed by TGA under nitrogen atmosphere from room temperature to 800 °C at 10 °C/min heating rate. TGA curves are presented in 5%T and 10%T) of poly(P-ddm/APbPc) were slightly lower than the recorded values of neat poly(P-ddm). The 5%T and 10%T values of pristine poly(P-ddm) were recorded as 320.6 and 357.8 °C, respectively, the value reduced to 290.7 and 340.2 °C for 25 wt.% loaded APbPc, respectively. The 5%T and 10%T of copolymers were slightly lower because of the poor relative stability of the aminoethoxy group of APbPc. However, the situation reversed in between 357 and 425 °C, the thermal stability of poly(P-ddm/APbPc) increased as the share of APbPc was raised. The ultimate impact was confirmed by analyzing the cY values, the cY value was increased from 41.6% to 46.8%, as the share of APbPc was increased from 0 to 25 wt.%. These improvements in the thermal stability parameters of copolymers can be dedicated to the amino groups containing APbPc monomer, which have good thermal resistance at moderate temperature, and formed very high crosslinked macromolecule structure. These results strongly correlate with the earlier discussed DMA data and the impact strength results. This confirms that the produced copolymers possess higher thermal stabilities as compared to the pristine poly(P-ddm).The thermal degradation curves of poly(P-ddm/APbPc) were sigmoidal shaped. From the summarized data, we can observe that the initial thermal decomposition temperatures  specimen. An increase of 1003 MPa in the copolymer stiffness and 24.6 °C decline in gT temperature was observed. The TGA curves under nitrogen atmosphere showed that the copolymers also exhibit excellent thermal properties. This study confirmed that the high-performance benzoxazine thermosetting resin performance can be improved by blending the APbPc monomer.In the current study, a high-performance poly(P-ddm/APbPc) copolymer was prepared. The blending of APbPc lowered the curing temperature of the P-ddm matrix due to the reactive –NH