Within this context, physical, mechanical , length change, and durability (porosity) tests were conducted on concrete made with nine different percentage replacements  of BA by induction of furnace steel slag aggregate (SSA). In addition, the chemical composition of aggregate through X-ray fluorescence (XRF) analysis and microstructural analysis through scanning electron microscopy (SEM) of aggregates and concrete were performed. The experimental results show that the physical and mechanical properties of concrete made with SSA were significantly higher than that of concrete made with BA. The compressive and tensile strength increased by 73% when SSA fully replaced BA. The expansion of concrete made with SSA was a bit higher than the concrete made with BA. Furthermore, a significant lower porosity was observed for concrete made with SSA than BA, which decreased by 40% for 100% SSA concrete than 100% BA concrete. The relation between compressive and tensile strength with the porosity of concrete mixes are in agreement with the relationships presented in the literature. This study demonstrates that SSA can be used as a full replacement of BA, which is economical, conserves the natural aggregate, and is sustainable building material since burning brick produces a lot of CO Though crushed stone aggregates are used in the concrete industry due to rapid urbanization, they are mostly imported from abroad, thereby, increasing the cost of concrete production. Due to the aforementioned issues, indeed, it is necessary to find possible alternative construction raw materials that can be used as coarse and fine aggregates in concrete construction works [In the utilization of industrial residues as construction raw materials, the concrete industry can play an important role in sustainable development, leading to considerable environmental benefits. Generally, aggregates (coarse and fine) occupy about 60–85% of the total volume of hardened concrete . Aggregaon works ,5,6. Steel slag is a byproduct of the steelmaking process which is produced during the separation of the molten steel from impurities in the steelmaking furnace, and it is used as coarse aggregate in concrete. It was found that steel slag aggregate (SSA) has superior physical and mechanical properties as well as lower carbon footprint and reduced negative environmental effects ,8. The cNetinger et al.  investig2) and natural aggregate which is mainly imported from abroad . The aim of this research work is to investigate the physical, mechanical , length change, and durability (porosity) performances of concrete made with nine different replacement percentages  of BA by induction furnace SSA. To gain a deeper understanding of the role of SSA on the performance of concrete, the relation between strength (compressive and tensile) and porosity of concrete mixes was discussed. Additionally, the chemical composition of aggregate through X-ray fluorescence (XRF) analysis was determined and microstructural analysis using scanning electron microscopy (SEM) of aggregates and concrete was performed.Several studies have been carried out to investigate the mechanical performance of concrete made with SSA, but few focused on durability . To the authors’ knowledge, there seems to be no published work on concrete made with induction furnace SSA as a replacement of BA. This induction furnace slag is used mainly for landfills and sometimes as an alternative aggregate in road construction, which is not very common due to lack of research data. The lack of research data, limited information, and knowledge on the mechanical and durability performances of concrete made with SSA as a replacement for BA motivate this research work. Within this context, comprehensive experimental studies were conducted on the possibility of using induction furnace steel slag as coarse aggregate replacement for BA. This is with the goal to reduce the consumption of industrial-made brick (reduce COTwo types of coarse aggregates (first-class burnt clay brick and induction furnace SSA) were used in this study. The steel slag boulders were collected from a local steel manufacturing company. Two different types of steel slag boulders were found: some were light in weight with more voids . Although no chemical treatment procedure was applied, the SSA was washed with tap water before use. The mixture proportions of the concrete mixes are summarized in All the concrete specimens were produced at constant water to cement ratio (w/c) of 0.45 and cement content of 350 kg/mIn addition, the temperature of the fresh concrete mixes was measured at all replacement levels. Since SSA is the byproduct of the steelmaking industry, the rate of expansion (length change) of the hardened concrete was monitored. Specimens (three replicates each) from three concrete mixes containing 0%, 50%, and 100% (by volume of BA) SSA were used for the investigation of expansion. The measurement of the longitudinal deformation of the specimens was conducted at different ages according to the French standard, NF P18-454 , using pA total of 216 cylindrical specimens (100 mm in diameter and 200 mm in length) for the nine different mixes was cast for compression and tensile (splitting) strength of the concrete mixes. Then, 24 h after casting, specimens were cured underwater (20 ± 2 °C) up to the day of the tests. The compressive and tensile strength tests were performed at 14, 28, 60, and 90 days to monitor the evolution of strength as per ASTM C39  and ASTMPa (%), was computed for the three states investigated according to Equation (1).The porosity of the concrete mixes was investigated using a technique based on water absorption porosity according to the French standard, NF P18-459 . The porScanning electron microscopy (SEM) of the BA and SSA was performed to understand the pore structure and surface roughness of the aggregates. Indeed, pore structure and surface texture of the aggregates are very important for concrete since they influence the physical, mechanical, and durability performances of concrete. Furthermore, SEM observations were also carried out on the concrete samples to detect possible cracking at the interface between BA/SSA and cement paste. Observed cracks could be correlated to the mechanical and durability performances of concrete made with these aggregates. All SEM tests were carried out using JEOL JSM-7600F Schottky Field Emission Scanning Electron Microscope. For the investigation of the interfacial transition zone (ITZ), completely dry concrete specimens were used, which had been polished with sandpaper and then submersed in ethanol solution.2O3 content as shown in The physical properties of the coarse and fine aggregates are summarized in The workability of different concrete mixes was evaluated by measuring the slump value of fresh concrete at the time of placing . No segrThe longitudinal expansion of concrete mixes as a function of time is presented in The dry density of concrete was measured on the same concrete cylinders that were used for the compressive strength tests. The average dry density and increase in dry density of hardened concrete are presented in 3, 2514 kg/m3, and 2668 kg/m3, respectively, at 28 days and 2145 kg/m3, 2539 kg/m3, and 2724 kg/m3 accordingly at 90 days. The highest density was observed for the concrete made with 100% SSA, which was about 25–27% higher for all ages than the concrete made with 100% BA (without SSA). This higher density of concrete made with SSA is directly linked with the higher specific gravity , 50% SSA, and 100% SSA was 2132 kg/mThe example of the stress–strain curves in compression of all concrete mixes performed at 28 days and 90 days is plotted in The average compressive strength of concrete mixes measured at 14, 28, 60, and 90 days is reported in By visual inspection it was observed that the SSA was highly angular in shape, had higher rough surface texture and lower flaky particles than the BA, which is the key feature to a stronger bond between the aggregate and cement paste in the concrete matrix. These results are consistent with the results available in existing studies . For a uThe analysis of the fractured surfaces of concrete specimens after compressive strength tests shows that the failure plane passes through the SSA see a and cemTo gain a deeper understanding of the role of different percentage replacement of BA by SSA on the compressive strength of concrete, normalized compressive strength at 28 days was calculated by dividing the 100% BA (SSA = 0%) concrete  and cement paste. The SEM images at the ITZ for both concrete mixes are presented in The use of SSA as a replacement for BA in concrete shows significantly higher compressive and tensile strength, which was 73% higher when BA was fully replaced by SSA.Lower workability was noticed for the concrete made with SSA than BA, which could be attributed to the higher rough surface texture and higher angularity of SSA than BA as well as better interlocking, which reduces the mobility of fresh concrete.The concrete made with SSA exhibited higher expansion than the concrete made BA.A significantly lower porosity was observed for the concrete made with SSA than BA. The maximum decrease in porosity was observed when BA was fully replaced by SSA, and the decrease was 45.80% lower than BA concrete.A satisfactory relationship between strength (compressive and tensile) and porosity was observed, which is consistent with the literature.SEM images showed that SSA was denser and has a stronger ITZ, which leads to the higher strength of concrete. By contrast, BA has more voids and cracks on aggregate as well as at the ITZ, which explains the lower strength of this concrete.2.From the experimental results of the nine mixes, this study reveals that SSA can be used as a full replacement for BA since SSA is denser, less porous, higher angularity, and has excellent surface roughness, which provides better mechanical and durability performances. Furthermore, SSA concrete provides environmental solutions by reducing the dumping problem, economical, conservation of natural aggregate, and sustainable green construction material since burning brick produces a lot of COIn this paper, the effect of steel slag aggregate (SSA) as a substitute for conventionally used brick aggregate (BA) on the physical, mechanical, and durability  performances of concretes was investigated. It is worth noting, however, that many studies have been conducted on the mechanical properties of concrete, while comparatively, few published data are available on the durability  as well as length change. To this end, nine concrete mixes made with different percentage replacements of BA by SSA were studied. The main findings of the influence of SSA on the physical, mechanical, and porosity of concrete can be summarized as follows:Future research should focus on utilizing other industrial by products and sustainable technologies such as 3D concrete printing ,42,43 wi


The paper presents a laboratory study assessing the feasibility of structural alkali-activated cement concrete with ground granulated blastfurnace slag (a by-product of steel production) and paper sludge ash. Paper sludge ash is used mainly as a source of Ca(OH)2 in the alkaline activator solution, and secondly as an additional source of aluminosilicates. A number of factors potentially affecting the activation process and the resulting concrete quality were investigated, including different dosage of activators, curing conditions and curing time. Mixes with paper sludge ash in the activator system developed high early concrete strengths at ambient temperatures and maintained adequate strengths for structural concrete. Further mix optimisation and mechanical and durability testing, accompanied by material characterisation, are required to establish the advantages of using this waste material in structural alkali-activated cement concrete.Pulp and paper manufacturing and recycling industries are a resource-intensive sector, generating 25–40% of the annual municipal solid waste worldwide. Waste includes abundant volumes of paper sludge, as well as the product of its incineration, namely paper sludge ash. These two waste materials are both predominantly landfilled. There is thus a drive for additional valorisation routes for these materials. This short communication focuses on the potential use of paper sludge ash in alkali-activated cement concrete; this type of concrete was estimated to potentially reduce CO PSA used on its own to activate the GGBS was not considered as previous studies showed lower strengths than those required for structural concrete (e.g. 3 cubes), tensile splitting strength and water absorption (30 min of immersion) were determined using PSA was provided by a newspaper recycling company in the south-east of England from the incineration of non-hazardous paper sludge from the secondary processing stage of recycled fibres (cleaning with 85°C water and bleaching to remove any ink left). The mixes of alkaline activators contained (a) analytical grade potassium hydroxide solution (KOH) and waterglass (WG)  results; AAC mixes had fsp values of c. 7–9% of the compressive strength (c. 7% for CEM-I); in most cases method 1 had higher strengths. Generally, AAC mixes showed a higher water absorption than the control CEM-I mix (see  mix see , except  mix see , there wSEM at 28-day curing confirms the development of hydration products for AAC mixes, justifying their good strength: mix 1 has a dense matrix of hydration products (This preliminary study assessed the feasibility of using PSA in activator systems of GGBS for structural concrete AAC. Curing at high available moisture and ambient temperature was successful for all AAC mixes, and overall good strengths were obtained. In WG activator mixes, the advantage of PSA was the higher early strengths and lower water absorption than mixes with WG only. However, 28-day strengths were lower than mixes with WG only. Introducing PSA as partial replacement of KOH improved both 7 and 28-day strengths. Further mix optimisation and mechanical and durability testing accompanied by material characterisation is required to establish the advantages of using this waste material in AAC concrete.


The main objectives of this research are to evaluate the effects of delamination defects on the measurement of electrical resistivity of reinforced concrete slabs through analytical and experimental studies in the laboratory, and to propose a practical guide for electrical resistivity measurements on concrete with delamination defects. First, a 3D finite element model was developed to simulate the variation of electric potential field in concrete over delamination defects with various depths and lateral sizes. Second, for experimental studies, two reinforced concrete slab specimens (1500 mm (width) by 1500 mm (length) by 300 mm (thickness)) with artificial delamination defects of various dimensions and depths were fabricated. Third, the electrical resistivity of concrete over delamination defects in the numerical simulation models and the two concrete slab specimens were evaluated by using a 4-point Wenner probe in accordance with AASHTO (American Association of State Highway and Transportation Office) T-358. It was demonstrated from analytical and experimental studies in this study that shallow (50 mm depth) and deep (250 mm depth) delamination defects resulted in higher and lower electrical resistivity (ER) values, respectively, as compared to measurements performed on solid concrete locations. Furthermore, the increase in size of shallow defects resulted in an increase in concrete resistivity, whereas the increase in sizes of deep delamination defects yielded opposite results. In addition, measurements done directly above the steel reinforcements significantly lowered ER values. Lastly, it was observed from experimental studies that the effect of delamination defects on the values of electrical resistivity decreases as the saturation level of concrete increases. Concrete, a key component in buildings and infrastructures , is one Corrosion of reinforcing bars (rebars) in concrete is known to be a major source of deterioration of concrete in combination with other mechanism such as freezing and thawing cycles and carbonation ,9,10. ReThe electrical resistivity (ER) method is one of the most suitable and easiest non-destructive evaluation (NDE) method to characterize concrete’s susceptibility to corrosion by evaluating its corrosive environment. Previous researchers have demonstrated that ER values of concrete can be correlated with its durability parameters such as corrosion rate ,14,15,16V is voltage, and I is current. The geometrical constant In practice, the voltage and current are measured at the surface of the object under investigation. The most common electrode layout in civil engineering applications is the Wenner setup, which was invented in 1905 for geology . In a We bridges . The RABThe data processing of ER method is simple and easily reduces to plotting the raw data. However, the interpretation of ER data in concrete is more challenging. One of the reasons is that the ER value of concrete is sensitive to its material properties and various environmental and external factors, which include water/cement ratio ,30, age Meanwhile, delamination defects are usually found beneath the surface of the concrete located at the upper layer, between two layers, or below the steel reinforcements . It is cHowever, there is only limited prior research regarding the effect of delamination defects on the ER measurements. For the influence of delamination defects to ER measurements, researchers only indicated that delamination causes difference in resistivity values. Chouteau and Beaulieu (2002), in their numerical investigation, found out that ER values over delamination defects in concrete were different from those values measured over sound concrete . In the The primary purposes of this research are to evaluate the effects of delamination defects in reinforced concrete slabs on the ER measurements and to propose a practical guide for ER measurements in concrete with delamination defects. For these purposes, four main tasks were performed in this study. First, a 3D finite element model was developed to simulate the variation of electric potential field in concrete over delamination defects with various depths and lateral sizes. Second, for experimental studies, two reinforced concrete slab specimens (1500 mm (width) by 1500 mm (length) by 300 mm (thickness)) with artificial delamination defects of various dimensions and depth were fabricated. Third, the electrical resistivity of concrete over delamination defects in the simulated concrete slabs and the two concrete slab specimens were measured by using a 4-point Wenner probe in accordance with AASHTO T 259. Lastly, the effects of delamination defects on ER measurements were systematically investigated and discussed based on collected data from a series of numerical simulations and experiments in this study. 3  were measured using two boundary probes placed at the location of the two internal electrodes. For comparison to the experimental data, the simulated potential difference was used to compute for the apparent ER using Equation (1).In this study, a series of numerical simulations was conducted to investigate the effect of geometric properties (depth and size) of artificial delamination defects in concrete and the presence of rebars on the effect of delamination defects. For the effect of the delamination depth, a model with a 300 mm square delamination was simulated at varying depths, starting from 25 mm to 275 mm deep with intervals of 5 mm. For the effect of delamination size, artificial square delamination defects with dimensions ranging from 25 mm to 1000 mm were studied, at a constant depth of 50 mm  and 250 mm (deep).3), river sand (701 kg/m3), crushed coarse aggregate (1049 kg/m3), and water (165 kg/m3), with a total weighted density of 2355 kg/m3 and a water/binder ratio of approximately 0.38. The mixture was designed to 28-day compressive strength of 35 MPa. Two layers of uncoated reinforcing steel bars with a diameter of 13 mm were placed in two-way orientation with center-to-center spacing of 300 mm placed at 50 mm (top layer) and 250 mm (bottom layer) depths. Artificial delamination defects using double-layered thin film with a thickness of 50 μm were incorporated in the manufactured concrete slabs and were placed at different depths with different sizes as shown in Two 1500 mm (length) by 1500 mm (width) by 300 mm (thickness) reinforced concrete slabs were fabricated at Dong-A University as part of a research project for the condition assessment and evaluation of old and deteriorated subway concrete tracks in the cities in South Korea. The concrete specimens were both composed of Type I Portland cement  of concrete was measured on the surface of the two concrete slabs by using a commercially available device (Resipod Proceq), which is based on the 4-point Wenner Probe principle see . The devIt is important to examine the effect of saturation conditions on ER measurements on concrete slabs since ER is strongly dependent on water content in concrete. ER values of dried concrete is extremely high that often exceeds the capacity of the measurement device. Accordingly, a number of researchers recommended wetting the surface by using a sponge or spraying a little amount of water before making a measurement ,48,49,50In this study, ER of concrete was measured over four locations on the surface of concrete with various saturation conditions to investigate the effect of saturation conditions on ER measurements. Four points were used to conduct this test see a,b: poinIn addition, ER of concrete was measured on five concrete cylinders (100 mm diameter and 200 mm height) with various saturation conditions of concrete to investigate the relationship between the degree of saturation and ER of concrete. The concrete cylinders were made with same concrete composition that were used for fabrication of the two concrete slab specimens. The concrete cylinders were immersed in water for 10 days, starting from oven dry condition, reaching a fully water saturated condition. The weight of concrete cylinders was measured before immersion and was continuously measured with the ER for every 20 min for the first one hour, every 30 min for the next nine hours, and every 24 h for a total of 10 days. In measuring the surface resistivity of the concrete cylinders, the Wenner probe device was placed at every 90° parallel to the height of the concrete cylinder, for two complete rotations in accordance with AASHTO TP95-11. The average concrete resistivity was computed from the average measurements of the five samples, which were computed individually by also averaging a total of eight measurement from four different locations. The degree of saturation (DS) was calculated by dividing the water content measured on a specific time over the maximum water content measured for the whole ten-day immersion. Mathematically, the equation for degree of saturation is:The electrical resistivity (ER) values of the two specimens were determined at different points presented as circled letters in At every point indicated, six probe configurations, shown in Experimental variability of the measured electrical resistivity (ER) is of interest when investigating the consistency and reliability of the test methods. In this study, thirty measurements were performed at each individual test location, with a single probe configuration, to investigate experimental variability of the measured ER values. The coefficient of variation  was used as a means of evaluating the experimental variability of ER measurements on the surface of concrete slab specimens. N = 30). It can be interpreted that the measured ER data can be represented by two statistical parameters . It was also observed that the distribution of ER values follows the normal distribution after the Kolmogorov–Smirnov (K-S) test. The experimental result for the shallow delamination in For deep delamination defects, on the other hand, the numerical simulation of the plain concrete and reinforced concrete models show a difference in results. The relative ER of the reinforced concrete is lower as compared to the plain concrete. Both the simulation models give a steady trend at increasing dimensions of delamination defects. It can be deduced from the numerical simulation of the plain concrete that the size of deep delamination defects does not affect the measurement of the ER, having a relative ER of nearly 1.0. Moreover, this, and the reinforced concrete simulation, prove that the presence of rebar caused the decrease in relative ER (approximately 0.9) for the reinforced concrete model. These results also validate measurements gathered for deep delamination defects , having experimental relative ER of 0.66 and 0.64, respectively. It should be noted that as explained in It is indicated in The discussion above validates the conclusions of existing research that ER values measured directly on top of a rebar will be relatively lower ,50,52. TIn addition, the effect of delamination defects tends to decrease as the saturation time increases (or degree of saturation increases). The effect of the surface saturation of concrete specimens to ER should be considered in practical engineering practice. AASHTO (American Association of State Highway and Transportation Office)  and a grThe effects of delamination defects to the electrical resistivity (ER) measurements were evaluated in this research paper. The researchers utilized the four-point (Wenner Probe) method in determining the resistivity of two reinforced concrete slab specimens. A numerical simulation through COMSOL Multiphysics was also conducted to be compared to the experimental data. In general, shallow delamination defects resulted in higher ER values, whereas probe configurations placed at deep delamination defects caused a decline in the measured concrete resistivity, all with reference to values gathered from solid concrete locations. In addition, the surface saturation of the concrete specimen decreases the values of electrical resistivities and minimizes the effect of delamination defects. The specific conclusions derived from this research are summarized as follows:(1)ER measurements conducted in this paper are variably controlled and precise considering that the COV computed are lower or near the values set by AASHTO TP358-15. ER values gathered also follow a normal distribution curve, which means that the measured ER data in this study can be represented by two statistical parameters .(2)The delamination defects in this study are divided into shallow delamination and deep delamination defects. Based on the experimental data gathered and the analysis of data conducted, it is deduced that shallow delamination defects (with depth of 50 mm), both small and large, contributes to a higher ER. On the other hand, small and large deep delamination defects (with depth of 250 mm) lead to a lower measured ER. The values gathered were compared to the ER of solid concrete. With reference to the average ER of solid concrete, the percent differences of shallow and deep delamination range from 26.90% to 49.35% and −17.19% to −47.19%, respectively. (3)It is observed in this study that the size of the delamination also affects the value of ER. As the size of the shallow delamination defects increases, the measured ER increases. On the other hand, the size of deep delamination defects is inversely proportional with the measured ER. It should be taken into consideration that measurements are done with the presence of steel reinforcement that may influence the values of ER, specifically for deep delamination defects, which are located below two layers of rebars.(4)It was concluded from the numerical simulation and experimental studies that ER values decrease with depth of delamination defects. For a plain concrete model, the relative ER closes to 1.0, whereas for reinforced concrete, relative ER decreases to 0.7. For the increase in size of delamination defects, shallow delamination defects in both plain and reinforced concrete models resulted in the increase in ER values. For deep delamination defects, the increase in size is negligible. Limitations are found in the numerical simulation, since other concrete properties and environmental factors such as degree of saturation, and the porous property of concrete were not included in the analysis. A more detailed and more systematic study of the effect of the presence of rebars, and/or the combination of the effect of the presence of reinforcements and delamination should be investigated both experimentally and numerically.(5)The presence of steel reinforcement has an effect on the measurements, resulting in a lower value of ER. Among the probe configurations used, the configuration C5, where the device was placed directly on top of the rebar, produced the smallest ER, whereas measurements made using C4 (the probe is perpendicular to the rebar), and C6  were within the range of the first three configurations. It can be inferred in this study that the presence of rebar near locations of measurements leads to a lower resistivity value. Measurements done at DL5, in which rebars are farther as compared to the points considered in shallow delamination of the concrete slab specimen 1, have overflowing (OF), or very high measurements.(6)It is established in this research that constant surface saturation decreases the value of ER. It is also established in this experiment that the gap of the ER measured along solid concrete locations and delaminated zones decreases due to the constant surface saturation of concrete. It is recommended in this study that in actual field measurements, to minimize the effect of delamination defects, saturation of the concrete surface should be done for at least 20–30 min. However, for measurements that are done right away (approximately at the first two minutes), delamination defects will greatly affect the ER measurements.


Recently, concerns have been rising about the impact of increasing the depletion of natural resources and the relevant generation of construction and demolition waste, on the environment and economy. Therefore, several efforts have been made to promote sustainable efficiency in the construction industry and the use of recycled aggregates derived from concrete debris for new concrete mixtures  is one of the most promising solutions. Unfortunately, there are still gaps in knowledge regarding the durability performances of RAC. In this study, we investigate durability of structural RAC subjected to wet-dry cycles. We analyze the results of an experimental campaign aimed at evaluating the degradation process induced by wetting and drying cycles on the key physical and mechanical properties of normal- and high-strength concrete, produced with coarse recycled concrete aggregates (RCAs) of different sizes and origins. On the basis of the results we propose a degradation law for wetting and drying cycles, which explicitly makes a possible correlation between the initial concrete porosity, directly related to the specific properties of the RCAs and the resulting level of damage obtained in RAC samples. The construction sector is one of the most environmentally impactful industrial activities in the world, as it requires a significant amount of natural resources and energy and generates an enormous volume of waste ,2. ThereIn a historical context, interest in RCAs began in the 1970s ,7. SinceThe main difference between RCA and ordinary aggregate is the presence of an aged mortar, the so-called attached mortar (AM), on the recycled aggregates . This diConsequently, recycled aggregate concrete (RAC) could also present higher absorption and higher porosity in relation to conventional concrete produced with natural aggregates. This makes durability a problem, since aggressive agents find it easier to enter concrete ,14,15,16The investigation of durability is certainly a very important aspect for the development and application of a new material. Durability can be defined as the ability of concrete to resist the actions of external agents without compromising the performance for which it was designed during its useful life. Therefore, the durability of isolated concrete and concrete structures depends on the proper selection of materials, mix-design, production and curing, and also depends on the interactions of the final material with its exposed environment . TemperaWu et al.  explaineHowever, there is no single parameter to determine the durability of concrete structures, especially when subjected to the actions of potentially aggressive environments. It is possible to take into account durability issues through mechanical properties, such as compressive strength and elastic modulus. Most of the structures in service experience wetting and drying cycles and temperature variation and, as a result, concrete structures are rarely completely dry, fully saturated, or in constant thermal conditions . To studThe influence of wetting and drying cycles on concrete was analyzed by numerical resolutions in a study by Li et al. , and it In the case of RCAs, according to Diagne et al. , the higObserving the absorption results of RAC samples, Oliveira et al.  reportedQi et al.  evaluateAlthough studies on the durability of concrete produced with RCAs have already been published, the main topics involving RAC subjected to wetting and drying cycles are mainly cases of exposure to sulfates and chlorides, and therefore little information on the exposure of recycled concrete to isolated wet and dry cycles can be found in the literature. In this context, there is still a knowledge gap about the influence of rain effects of typical tropical zones on the durability of RAC, in particular, in relation to processes of alternating cycles of wetting and drying together with temperature variations.The present study reports on an experimental investigation aimed at analyzing the influence of the use of RCAs of different origins and sizes on wet-dry durability of normal (35 MPa) and high strength (60 MPa) concrete. Through a scientific mix-design technique for RACs previously developed by the authors , which c3, 28-day compressive strength of 40.6 MPa, and actual packing density of 0.67.The cement used, in this study, was “high initial strength Portland cement” , labeled CPV-ARI, according to the National Brazilian Standard (NBR) 16697 , with th3, solid concentration content of 35%, and saturation dosage of 1.5% (solids of SP based on the cement weight).The superplasticizer used in all mixes for workability control was a polycarboxilate superplasticizer, labeled “MC Powerflow 1180” , with the following main properties: specific gravity of 1070 kg/m3 [Natural quartz sand was used in this study as natural fine aggregate (NFA), with the following characterization: maximum grain size of 4.75 mm, specific gravity of 2447 kg/m3 , water a3 , and act3 .Granite type stones were used as the natural coarse aggregate (NCA) in the following two types of sizes: the first type was “NCA_C0” with a nominal diameter ranging from 4.75 to 9.5 mm (size named by “coarse aggregate 0”); the second type was “NCA_C1” with a nominal diameter ranging from 9.5 to 19 mm (size named by “coarse aggregate 1”).The recycled concrete aggregates (RCAs), employed herein, were obtained from the following two different sources : concretIn order to characterize both natural and recycled coarse aggregates, several tests were carried out and the main results are shown in The reported data showed that the properties of the aggregates depended mainly on the characteristics of the original concretes (L-waste and D-waste). Although the RCA particles obtained from the two sources presented similar properties for the fraction C0, for the class C1 this difference was more evident. In fact, since the L-waste had a maximum dimension of the original aggregate of 9.5 mm, generating aggregates of 19 mm led to greater amounts of attached mortar to the grains . As expeIn this study, a scientific mix design for the produced concrete mixtures was performed using the so-called compressive packing model (CPM) . This meThe optimization method was performed by maximum granular compactness of concrete, using the above-presented data of the actual packing density of the raw materials. The recycled materials were added to the mixture in a dry condition and the singular high absorption of the RCAs was considered during the definition of the mix proportioning. The absorption value of 50% of the total absorption obtained experimentally was used, since this value was previously shown  water did not take into account the absorption water of the aggregates. The aggregate proportion was fixed at 50 for sand, 25 for class C0, and 25% for class C1 in relation to the overall volume of aggregates (fine and coarse). For each class, five concrete mixtures were designed, varying the coarse aggregate, as follows:(1)Reference with only natural aggregates (NCA_C0 and NCA_C1);(2)100% RCA_L_C0 in fraction C0 (RCA_L_C0 and NCA_C1);(3)100% of RCA_L_C1 in fraction C1 (NCA_C0 and RCA_L_C1);(4)100% RCA_D_C0 in fraction C0 (RCA_D_C0 and NCA_C1);(5)100% of RCA_D_C1 in fraction C1 (NCA_C0 and RCA_D_C1).The concrete mixtures were developed for the following two classes of compressive strength: normal strength with 35 MPa and high performance with 60 MPa. All mixtures were produced with 30% effective paste, and “effective paste” was the volume of free paste in the mixture  in relation to the total volume of concrete, in which the mixing  of each mixture (AM) and the new mortar volume  given by the sum of sand, cement, water, and superplasticizer:i represents the weight used for each fraction  developed and improved for cases of RAC by Tam et al.  and Tam The mixing procedure was performed in the following order: Initially, homogenization of all coarse and fine aggregates by mixing for 1 min; followed by the addition of half the total amount of water and mixing for 1 min for better absorption by RCAs; then, the cement was added and mixed for 1 min with the aggregates; finally, the rest of the water  and the superplasticizer were added and mixed for 8 min (superplasticizer action time), concluding the concrete mixing process. The casting of the concrete was carried out in two layers, followed by mechanical compaction for 30 s. The samples were demolded after 24 h and the cure was carried out in a wet chamber with relative humidity of 100% and temperature of 21 °C.The degradation process by wetting and drying cycles started at the age of 28 days. Cylindrical samples, 75 mm in diameter and 150 mm in height, were used. Initially, the samples were saturated in water for 48 h, and then the cycles started. The durability test of concrete samples subjected to accelerated wetting and drying cycles was based on NBR 13554  and ASTMAfter the degradation process, the concrete samples were characterized by determining their relevant mechanical properties, such as compressive strength, elastic modulus, tensile strength, and mass loss. The weighing of the samples was carried out in order to follow the mass variation. The weight loss test was performed on three samples of each mixture for each level of wet-dry degradation. The samples were weighed in an oven-dried condition (after mass consistency) before the degradation process. After 25 cycles, the same samples were weighed again in an oven-dried condition. The same procedure was performed for the samples of 50 wet-dry cycles. The calculated mass loss is the average of the percentage differences between the initial mass and the mass after degradation of each sample. It is worth mentioning that, for all mixtures, non-degraded samples were kept protected in a wet chamber (21 °C temperature and 100% humidity) and tested as reference at the same age as the samples degraded by 25 and 50 cycles.The characterization of all mixtures was carried out through the tests detailed in This section presents the results of the experimental characterization of the ten concrete mixtures produced in this study. Many authors have stated that the presence of RCA caused a reduction in the workability of concrete, caused mainly by the higher absorption capacity of these materials ,47. Howeopen), higher void index, and lower specific gravity as compared with natural concrete. These results are consistent with the conclusions that have been obtained in several studies available in the literature [The results of physical properties show that recycled concrete has higher total water absorption , the higher the open porosity of concrete (wopen) . This is explained by the fact that the open porosity of concrete also depends on the raw materials employed within the mixture, and, in the specific case of RACs, it is influenced by the presence of the porous attached mortar inside or around the RCAs particles. Thus, the strong connection between these two parameters, that is, the trend of the increasing curves in 1, k2, and VM,0 represent numerical parameters calibrated for both normal and high strength classes:1 was calibrated with 7.3 for C35 and 4.2 for C60, k2 with 30.0 for both classes, and VM,0 with 45.0 for C35 and 55.0 for C60.Meanwhile, from the percentage of total mortar volume of each mixture , the following relationship is shown in c,28) prove that all recycled concretes obtained similar values to natural concretes for the studied classes, according to the initial proposal of this study, that is, the premise to understand the influence of the presence of RCAs in concretes of the same strength subjected to degradation by repetitive wet-dry cycles. In fact, the maximum difference between the expected compressive strength and the experimentally obtained compressive strength was 4% for both normal strength and high-performance mixtures as compared with the predicted values of 35 and 60 MPa. These results reinforce the excellent capacity of the specific mix design methodology described (based on [The results obtained from compressive strength at 28 days (fbased on ) to predc,28), as compared with the values obtained for concretes with 100% NCA, there was a maximum variation of 1.8% decrease to 3.7% increase in RACs of C35 , and a maximum variation of 1.3% to 6.5% increase in RACs of C60 . Finally, the results of splitting tensile strength at 28 days  of C35 showed a variation of 3% decrease to a 7% increase in RACs in relation to the natural mixture . The results of C60 expressed a maximum increase of 12% (from both C60-L-C1 and C60-D-C0) as compared with the result of the natural concrete. Therefore, in the high strength class, all RACs obtained a better result than the natural mixture for these two main mechanical properties.For elastic modulus at 28 days  the more porous structure ” and “REF(WD50)”, according to the samples to which they serve as reference.The physical and mechanical degradation of concrete subjected to wetting and drying cycles can be associated with the different hygrometric profile which is generated within the concrete element. As a matter of principle, during the wetting phase, the open pores are filled by water during drying, depending on the concrete size and the duration of each cycle, only the cortical area of the element is able to be fully dried. This phenomenon promotes the shrinkage of the external layers while the internal core  locks the volume change . This reThe mass loss results for natural aggregate concrete (NAC) and RAC after 25 and 50 wet-dry cycles are shown in In both strength classes, the mass loss rates do not show significant differences with an increased number of cycles. In general, the change in the mass of concrete  occurs due to mortar fragmentation during wet-dry cycles. In the drying stage, a pressure arises due to the shrinkage of the concrete by the evaporation of the internal water, thus, the concrete becomes weaker and fragmented with the creation and evolution of micro cracks. This aspect is also confirmed by the fact that during the wet-dry tests there were small components of the concrete in the water tank. Consequently, the mass of the samples decreases. With the repetition of the cycles, this process repeats, causing more and more reductions in the mass. However, as shown in the results, this occurs at a (approximately) constant rate of change.Finally, in both C35 and C60, mixtures produced with the RCA of class size C1 from laboratory waste (C35-L-C1 and C60-L-C1) stand out for higher mass loss as compared with other mixtures, while natural mixtures (C35-NAT and C60-NAT) have the lowest mass loss results. Therefore, with the joint action of wetting and drying processes, the results show that these interactions modify the properties and the microstructure of RACs more clearly than natural concretes. This fact can be explained as follows: Natural concrete presents only the new mortar in concrete undergoing this aggressive process, while RACs undergo these processes in the new mortar, and also in the old mortar attached to the grains of RCAs, consequently RACs suffer further damage.The typical stress-strain responses obtained in compressive strength tests of normal and high strength classes in the wet-dry degradation study of RACs are presented in Samples of the typical rupture that occurred in each class in the compressive tests after wetting-drying degradation are shown in This variation in the cracking pattern of the samples after wet-dry cycles can be explained by the fragmentation of the mortar and the increase in the volume of pores, previously described. This modification in the internal structure of the concrete, caused by the degradation process, can result in a weaker “line” in the concrete , which becomes the “path” of the cracking process during the application of stress in the compressive test.The results confirmed that all samples from both classes suffered a loss in compressive strength when subjected to repetitive wetting and drying cycles. The normal strength class reached degradation percentage decreases from 6.9% to 7.8% at the end of 25 cycles and from 14.5% to 20% after 50 cycles a. For loThe percentage decrease in compressive strength was higher for the normal strength class than for the high-performance class for both two levels of cycles. This fact was expected due to the previously explained mass loss, i.e., it was related to the higher porosity (associated with greater water penetration in the wetting phase) and the lower resistance (associated with the lower capacity to withstand the stresses generated by the shrinkage in the drying phase) of C35. For C60, the compressive strength percentage decreases ranged from 3.2% to 4.6% after 25 wet-dry cycles and from 9.7% to 13.5% after 50 wet-dry cycles a. The saFor C35, the values of elastic modulus decrease of samples degraded by 25 wet-dry cycles ranged from 3.8% to 6.7%, and, after 50 cycles, the values increased for 13.8% to 18.1% as compared with control samples b. For thFor the normal strength class, tensile strength values showed a decrease of 6.6% to 9.0% for samples degraded by 25 cycles, and a decrease of 17.4% to 20.3% for RACs, and 13.5% for natural concrete after 50 cycles c. Therefopen), and the variations obtained in the main mechanical properties of concrete after wet-dry degradation, that is, compressive strength (fc), elasticity modulus (Ec), and tensile strength (ft). The three proposed relationships are described in the following equations:With the experimental results obtained for the properties discussed above, a generalized degradation law is proposed for RAC subjected to wet-dry cycles. The law represents the relationships between an initial property of the intact concrete, in this case, the concrete open porosity , there would be no degradation of concrete, since the water would not flow within the concrete structure and it would not cause damage to the material.In all graphs, the following can be observed: On the one hand, the points above are the results for 25 wet-dry cycles (WD25) of the ten concrete mixtures and they indicate that the influence of this degradation level is less relevant; on the other hand, the observation of the lower points, which represent 50 wet-dry cycles (WD50), highlights two very evident trend lines, one for each strength class, where the right trend line represents C35 (higher porosity) and the left trend line represents C60 (lower porosity). Thus, two numbers (one for each resistance class) were calibrated for parameter a for compressive strength a, followIn the three graphics, in addition, the points more to the left of each of the four groups of points refer to the mixtures of natural concrete (C35-NAT and C60-NAT), since these concretes have lower porosity in each class, because they have a lower total mortar volume than RACs  there is a greater variation in durability capacity (y-axis) than for the normal strength class. This confirms that the presence of a more porous aggregate causes a greater impact on the wet-dry resistance of C60. In other words, as the porosity of the aggregate is directly related to the attached mortar content, the durability of C60 is more sensitive to the presence of AM than C35.The shape of the curves shows that the graph of the high-performance class is more vertical for all three properties, which indicates that for a smaller variation in concrete porosity  showed decreases in compressive strength, elastic modulus, tensile strength, and mass value, when evaluating the results obtained for samples degraded by 25 and 50 wet-dry cycles.The percentage decreases in the properties studied were greater for the normal strength class than for the high-performance class. This evidence is associated with the higher porosity of C35 mixtures.For higher number of cycles, it is evident that the capacity of the natural mixture to resist degradation by wetting-drying cycles is greater than RACs, for both C35 and C60. It is believed that this occurs because the natural concrete presents only the fragmentation of the new mortar when subjected to degradation, while RACs undergo this process in both the new mortar and the mortar attached to the RCA particles, suffering, therefore, greater damages.A wet-dry degradation law for RAC is proposed in this study for the key mechanical properties after wetting and drying degradation  as a function of the initial open porosity of the concrete, which is also directly related to the total mortar volume of concrete.Finally, as the RAC resistance to wet-dry degradation is governed by the initial open porosity of the concrete, it would be possible to use RAC in structures subjected to environmental conditions similar to the ones analyzed herein through the control of this physical property in the mix design stage.This study reports the results of an experimental study on the physical and mechanical performance of structural concrete made with either natural or recycled aggregates and subjected to degradation processes similar to environmental conditions of temperature and humidity variation. Specifically, it summarizes the results of an experimental investigation aimed at analyzing one of the aspects related to the durability of normal and high strength concretes produced with different types of RCAs, after being subjected to different levels of wetting-drying cycles. Particularly, the following considerations can be highlighted:


Use of nitrofurantoin for uncomplicated cystitis and recurrent urinary tract infections is common practice. While the majority of patients tolerate this medication without issue, it is important to be cognizant of adverse reactions, as these can impact patient’s quality of life. Nitrofurantoin-induced pulmonary toxicity is a rare side effect that can present with various clinical manifestations, imaging abnormalities, and pathologic findings. We describe a case of chronic pneumonitis in a patient on suppressive nitrofurantoin therapy presenting with dyspnea and hypoxemia. Nitrofurantoin is an oral antibiotic that functions to disrupt normal bacterial cellular function. It does this by altering ribosomes and subsequently changing protein synthesis, metabolism, and synthesis of deoxyribonucleic acid (DNA), ribonucleic acid (RNA), and the cell wall. Nitrofurantoin is also bactericidal in urine providing additional clearance of bacteria . This leWhile nitrofurantoin-induced pulmonary toxicity is well known in the literature, it is not commonly included in the initial differential for chronic exertional dyspnea with hypoxemia. Here we describe a case of worsening chronic dyspnea in a patient on preventative nitrofurantoin therapy for recurrent urinary tract infections.A 70-year-old female presented to the pulmonary clinic for repeat evaluation of chronic dyspnea on exertion. Her pertinent past medical history included obesity, obstructive sleep apnea, and non-obstructive coronary artery disease. Social history is notable for remote tobacco use with cessation at age 18. She had been seen for similar complaints approximately five years ago with a normal work up to include spirometry, six-minute oxygen desaturation test, chest X-ray, echocardiogram, left and right heart catheterization, and high-resolution CT chest (HRCT). At that time, she had a borderline positive methacholine-challenge test (noted to have a 28% reduction in forced expiratory volume in one second (FEV1) with the 16 mg dose of methacholine). She was trialed on inhaled corticosteroid therapy without improvement, as well as a short-acting β-agonist with subjective relief.In February 2018, she presented to the emergency department with pre-syncopal symptoms, acute on chronic worsening of her dyspnea, and falls. The patient was afebrile and normotensive, but hypoxemic requiring supplemental oxygen via nasal cannula. Physical examination revealed bilateral fine crackles. CT pulmonary angiogram during admission revealed new diffuse peribronchovascular ground-glass opacities with sub pleural involvement, multiple perifissural nodules, and right hilar lymphadenopathy  as well as transbronchial biopsies. BAL showed 43% lymphocytes, 16% polymorphonuclear neutrophils, 2% eosinophils. The cluster of differentiation (CD)4/CD8 ratio was ~1 . She had negative bacterial and acid fast bacilli cultures on BAL. The patient had a respiratory polymerase chain reaction (PCR) panel which was negative for influenza A/B and other common respiratory pathogens including Mycoplasma pneumoniae and Chlamydia pneumoniae. Autoimmune serologic testing was negative. Her transbronchial biopsy showed normal alveolar tissue, thought to be a sampling error. The patient was not initiated on corticosteroid therapy. Prior to discharge, the patient failed an oxygen desaturation test  showed a greater than 10% improvement in DLCO that paralleled both symptomatic and radiographic improvement Table .Specifically, follow up HRCT at three months and nine months demonstrated improvement in ground-glass opacities and a decrease in the size of perifissural nodules Figures -3. She wMost patients who present with pulmonary reactions to nitrofurantoin are women -8. This Acute hypersensitivity pneumonitis presents on average 8.7 days after initiation of therapy according to a small case series . DiagnosChronic pneumonitis is most commonly observed in women in their seventh decade who are on long-term therapy . SymptomDiagnosis of chronic pneumonitis is based on history, consideration of other more common etiologies , and clinical response after discontinuation of the offending agent. Physical exam findings are non-specific and can include inspiratory crackles, clubbing, +/- hypoxemia . ImagingChronic nitrofurantoin use is associated with a higher risk of parenchymal injury. In one retrospective, matched-cohort study of 13,421 participants. chronic nitrofurantoin therapy had an adjusted risk ratio of 1.53 (CI = 1.04-2.24) . UnfortuNitrofurantoin is a bactericidal antibiotic that acts on multiple biochemical pathways of the bacterial cell. It is used as first-line, empiric therapy for uncomplicated cystitis as well as daily for prevention for recurrent urinary tract infections. Because of this, the majority of patients that will have an adverse event related to nitrofurantoin are women. Acute hypersensitivity typically presents around day eight or nine of exposure to the drug. It presents with fever, dyspnea, and cough. Labs and imaging display a peripheral eosinophilia, leukocytosis, elevated ESR, and consolidation with pleural effusion on chest X-ray. The backbone of treatment is the cessation of nitrofurantoin therapy. While acute reactions are more common, it is important to remain vigilant for chronic manifestations. When evaluating interstitial lung disease, a thorough medical history is paramount, as many pulmonary toxicities due to medications are reversible if identified early. Our patient’s history of progressively worsening dyspnea on exertion with concurrent, daily nitrofurantoin use fit with a diagnosis of chronic pneumonitis. Our patient demonstrated a peribronchovascular distribution likely consistent with organizing pneumonia, which has rarely been described in the literature. After undergoing extensive work up to rule out infectious, rheumatologic, and other cardiopulmonary disorders, she was diagnosed with nitrofurantoin-induced lung injury. Her nitrofurantoin was stopped and she had subjective improvement, as well as near-resolution of HRCT abnormalities.


Although various prophylactic and/or postoperative systemic antibiotic regimens have been suggested to minimize failure after dental implant placement and postoperative infection, the role of antibiotics in implant dentistry is still controversial. The purposes of this questionnaire study were to determine the current antibiotic prescribing habits of clinicians in conjunction with dental implant placement and to understand whether any consensus has been reached among implant surgery performing clinicians.An electronic questionnaire was sent by electronic mail to all members of the Turkish Dental Society. The questions were related to whether antibiotics were routinely prescribed either pre- or/and postoperatively during routine dental implant placement. The respondents were also asked to specify their workplace and education. The results were analyzed using SPSS software. Descriptive and chi-square analyses were used to compare categorical data; Kruskal–Wallis test was used to compare the quantitative data by category.p < 0.001), but there was no statistically significant difference between the postoperative antibiotic prescription choice of the clinician according to the clinicians’ experience (p > 0.05). A total of 175 of the clinicians preferred to prescribe preoperative antibiotics when there was systemic comorbidity; 99 of the clinicians preferred to prescribe antibiotics before every implant surgery. The aminopenicillins were the most commonly prescribed antibiotics by the clinicians. A total of 38.58% of the respondents (n = 130) who were prescribing preoperative antibiotics, 2000 mg aminopenicillin was given 1 h before the surgical procedure. Dentists and solo private practitioners were prescribing more preoperative antibiotics .A total of 429 members responded to the questionnaire. The clinicians having more experience had a greater tendency to prescribe preoperative antibiotics (There was no consensus among clinicians regarding the use of antibiotics in association with routine dental implant placement. Aminopenicillins were the most commonly prescribed antibiotics for both pre- and postoperatively. Furthermore, most of the antibiotic regimens being used are not in accordance with the current published data. The basic aim of the dentistry is to protect and/or restore dentomaxillofacial structures. Especially, coping with missing teeth of the patients is one of the main duties of dental professionals. Nowadays, the best promising routine way to replace a missing or poorly prognosed tooth with high success and survival rates is placing dental implants . ConsideDuring placement of dental implants, oral microflora should be controlled, as pathogenic bacteria present in the oral environment may cause peri-implant infections in implants as well as in the teeth, which may impair the early healing of the implant, i.e., osseointegration , 4. UnfoAlso, a recent network meta-analysis (NMA) by Romandini et al. stated that data in the current literature is unable to reach high evidence . As a reThe use of postoperative antibiotics is also a controversial situation in the literature. Due to heterogeneity and insufficient data in clinical studies of postoperative antibiotic use in the literature, there is no conclusive report regarding its relationship with postoperative infection .Clinicians should never forget that the extensive use of antibiotics in order to decrease implant failures could bring its disadvantages. It should not be considered that antibiotic administration on patients may be related only to dental implant survival or success. Improper antibiotic use also has both individual and social effects. Hypersensitivity reactions caused by antibiotics can cause serious medical problems . In addiHowever, the fact that in the literature has not been reached regarding pre- and/or postoperative antibiotic use related to implant surgery, the conclusion in the literature means that clinicians lack the full scientific resources available to them for making their clinical decisions.The aim of this study was to determine the pre- and/or postoperative antibiotic prescription habits of clinicians in Turkey who have been performing dental implant surgery according to their year of experience, presence of specialty in the field, their title, and workplace. In this study, the circumstances in which the clinicians prefer prescribing preoperative antibiotics were also investigated, so as to understand whether there is a conclusion among clinicians, and to determine the level of compliance of the clinicians' habits with the current literature.This study was designed as a cross-sectional questionnaire intending to understand antibiotic prescribing habits of the clinicians performing implant surgery in Turkey. Ethical approval was obtained from the Istanbul Okan University Ethical Committee  with the acceptance protocol 98. An electronic questionnaire was created with Google® Forms . The questionnaire link was sent to all those of the members of Turkish Dental Association (Türk Dişhekimleri Birliği [TDB]) via e-mail by the secretary service of the association and the dynamic responses were automatically recorded on to the Google® Forms for 3 months (February–April 2019). All responses were anonymous. The questionnaire consisted of 15 questions. The clinicians were asked to assume that the patients had no antibiotic allergies. Generally, there were three subdivisions in the questionnaire, the qualifications of the clinician, preoperative antibiotic prescription, and postoperative antibiotic prescription habits  for Windows Version 23 . The descriptive and chi-square analyses were used to compare the categorical data. The Kruskal-Wallis test was used to compare the quantitative data by category. The analysis results were expressed as median values (minimum-maximum) for the quantitative data and frequency (percentage) for the categorical data. The significance level was taken as p < 0.001). The clinicians having more experience had a greater tendency to prescribe preoperative antibiotics.A total of 429 of the 19,963 (2.15%) members of the TDB responded to the questionnaire. The preference of the preoperative antibiotic prescription habit according to the years of experience of the clinicians is shown in Table p > 0.05).In Table p < 0.001)  were compared, a significant difference was observed between the parameters (1) Table . A totalp = 0.002)  showed a statistically significant difference (2) Table . While 3p = 0.014)  Table . The prep = 0.671)  who were prescribing preoperative antibiotics, 2000 mg aminopenicillin given 1 h before the surgical procedure was the clinical choice followed by 19.3% of the respondents (n = 65) who preferred 1000 mg aminopenicillin given 2 times per day before 1 day of the procedure and aminopenicillin given 2 times per day before 2 days of the procedure 17.5% of the respondents (n = 59). Postoperatively, the most common antibiotic regimen was 1000 mg aminopenicillin two times per day for 5 days (53.5%).In Tables p = 0.002; p = 0.182 respectively).The preoperative and postoperative antibiotic prescription rates of the clinicians according to their practice type  are shown in Tables p < 0.001) could be seen. While 80% of clinicians prescribing preoperative antibiotics prescribe antibiotics postoperatively; 91.2% of the clinicians do not prescribe antibiotics preoperatively but prescribe antibiotics in the postoperative period.In Table Postoperative infection can be the nightmare of any clinician who is dealing with regenerative and reconstructive oral surgical procedures. The best way to achieve success in daily clinical practice is based on the following evidence-based data. Unfortunately, there is no consensus on some important issues in the current literature and the right perioperative antibiotic regimen in implant surgery is one of them. It is extremely important, especially these days, in which implant dentistry is a part of the routine in our clinical practice, that we are dealing with a serious medico-social event such as antibiotic resistance and with antibiotics’ other adverse effects such as hypersensitivity reactions , 13.It is vital to have evidence-based data to enable our clinical practice to attain a high standard and great success. Success does not mean just the success of the surgical operation or the successful osseointegration of the dental implants. Prescribing antibiotics in a necessary way is also a part of the whole patient care. A study conducted by Marra et al. revealed that between years 1996 and 2013, there was an increase in antibiotic prescribing rates in dental professionals in British Columbia, although there was a decrease in other medical professionals . AccordiNowadays, safety does not mean just the patients’ postoperative period without any complications for a clinician, as well as not having any medicolegal issues related to dental procedures including implant surgery. Unfortunately, one of the leading expectations of the patients visiting dental clinics is to be prescribed antibiotics when they have an emergency situation like endodontic emergencies or surgical operations . This siClostridium difficile infections, and the importance of appropriate antibiotic use [As well as the lack of supportive data, the insufficient update mechanism could cause this diversity and different choices in antibiotic prescription related to implant dentistry. A recent study conducted by Kim et al. showed that different interventions such as educational tool guidelines and some restriction tools could induce positive behavioral change in dentists related to implant dentistry, and both simple, and impacted teeth extraction . Also, notic use . Furtherotic use .In some cases, educating the clinicians and patients could not be enough to control antibiotic usage. Because of that, controlling the sales of antibiotics like some other drugs by the public healthcare system is beneficial to cope with inappropriate antibiotic usage. In Turkey, antibiotics are sold only on prescription and there are different payment possibilities. Antibiotics are paid by the public healthcare system when the patient is referred from public or university clinics. Furthermore, there is an integrated family medicine system. Every citizen and registered foreigner have their own registered family physician. The patients with an antibiotic prescription from private clinics could get approval from their family physician, in this way the prescribed antibiotics are paid by the public healthcare system. Otherwise, patients are paying by themselves.Escherichia coli (E.coli) isolates against amoxicillin ranges between 35.3 and 67.6% showing an increase especially to the southeastern direction and also in Ireland; the resistance rates of Enterococcus faecium (E.faecium) isolates against amoxicillin ranges between 62.5 and 97.2%; whose isolates are also showing resistance against vancomycin and high-level gentamicin [E.coli isolates against amoxicillin and ampicillin was 77% and amoxicillin with clavulanic acid was 62 %; the resistance rates of E.faecium isolates against amoxicillin was 89% [Controlling antibiotic prescription by the public healthcare system does not help only appropriate antibiotic prescription or usage. Also, this will help to discover the surveillance in countries and to compare the prescription and resistance rates between countries, years, and different antibiotic families. In recent years, especially aminopenicillins and aminopenicillins with enzyme inhibitors are frequently prescribed antibiotics . Unfortuntamicin . In Turk was 89% . Compari was 89% , 24. As With the findings of this study, it can be stated that there was no standard antibiotic prescribing habit related to implant dentistry among Turkish clinicians who participated in the questionnaire and our findings are parallel with current literature. In a questionnaire study conducted by Deeb et al., the authors aimed to investigate the antibiotic prescribing habits of the clinicians related to implant surgery . Their fAs mentioned before, the factor that clinicians are not updating themselves with current data could be also one of the reasons why clinicians do not prescribe antibiotics in a proper way. Although systematic reviews and meta-analyses showed that oral administration of 2 g or 3 g of preoperative amoxicillin before 1 h of the operation may be helpful in preventing postoperative infection in peri-implant tissues, only approximately quarter of the respondents has been prescribing preoperative antibiotics for every implant surgery and half of them is practicing this in a right way , 8–10. Hn = 220) were prescribing postoperative antibiotics in case of systemic comorbidities, which could cause immunosuppression, but there was a lack of consensus in duration.Furthermore, the majority of the clinicians were prescribing antibiotics postoperatively and they had almost a consensus for their choice of antibiotics (aminopenicillins and aminopenicillins with beta-lactamase inhibitors with 93.8%). There was a diversity in the duration of antibiotic usage, but more than half of the respondents who were prescribing postoperative antibiotics prefer that their patients took antibiotics for 5 days. A recent systematic review citing 11 RCTs and 3 retrospective studies by Park et al. concluded that postoperative antibiotics should ideally be used in healthy patients with systemic symptoms of infection or in patients with insufficient support from the immune system . EspeciaIn a study conducted by AbuKaraky et al., in which they had investigated the antibiotic prescribing habits of Jordanian clinicians, they investigated the reasons motivating clinicians to prescribe in different procedures related to implant rehabilitation . In the p = 0.002). However, the workplace of the clinicians did not have a statistically significant effect on the postoperative antibiotic prescribing habit (p = 0.671). Finally, the years of experience both in dentistry and implant dentistry positively affected the antibiotic prescription habit (p < 0.001); years in the profession possibly pushed the clinicians to be more or overcautious; or the reason could be the lack of sufficient updating in the current literature.When the data interpreting clinicians’ qualifications and workplace was examined, it was shown that these parameters caused a statistically significant difference for a preoperative antibiotic prescription habit, but not a statistically significant difference for the postoperative one. When the rates of the answers of the respondents were grouped according to their title, the postgraduate students’ choice was to prescribe more preoperative antibiotics and the dentists’ choice was to prescribe fewer preoperative antibiotics; especially in the case of systemic comorbidities . In this study, most of the respondents were frequently performing implant surgery and almost 33.8% of the respondents were specialists for or postgraduate students in implant-related majors. Comparing other similar studies in the scientific literature, the response rate in the study conducted by Deeb et al. in which they investigated perioperative antibiotic prescription habit of the clinicians who were a member of American College of Oral and Maxillofacial Surgeons was 15% (217 of 1436) . AnotherWithin the limitations of this study, it could be concluded that in Turkey, there was no consensus on the antibiotic regimen among clinicians dealing with implant dentistry. The lack of sufficient evidence-based data should be supported with well-designed, multi-center, and large-scale RCTs for preoperative and especially for postoperative antibiotic regimens related to implant surgery. Finally, there could be a need for providing recent scientific data to the clinicians, creating some control mechanisms regarding antibiotic prescriptions or antibiotic stewardship like medical hospitals.


A more defined response on histone methylation was observed in H3K9 than H3K27 to Met supply, where maximal histone methylation in H3K9 was observed with 125 μM of Met. This greater histone methylation in H3K9 at 125 μM was accompanied by greater cellular protein concentration. The linear increase in Met supply causes a linear decrease in global DNA methylation, while linearly upregulating genes related to the Met cycle . The histone methylation data suggest that, to some extent, methyl-donors such as Met may affect the methylation sites, H3K9 and H3K27, and consequently causing a different epigenetic alteration. In the context of the dairy cow, further refinement to this FRET assay to study histone methylation could lead to establishing novel potential mechanisms of how dietary methyl donors may control the structural conformation of the bovine genome and, by extension, gene expression.Methionine (Met) is an essential precursor of S-adenosylmethionine (SAM), which is the primary methyl donor required for biological processes such as DNA and histone methylation, which alter gene expression. In dairy cows, dietary Met has been observed to exert transcriptional alterations with beneficial effects on milk biosynthesis; however, the extent of these effects via SAM remains unknown. Therefore, we evaluated the effect of Met supply on histone methylation in lysine residues K9 and K27 in the histone tail H3 via a fluorescence resonance energy transfer (FRET) system in immortalized bovine mammary alveolar epithelial cells (MACT) incubated varying concentration of Met. The histone methylation data was complemented with global DNA methylation, cellular protein synthesis, and RT-qPCR analysis of genes related to Met cycle, DNA and histone methylation, AA transporters, and protein synthesis. The histone methylation data was performed on MACT cells seeded at 30,000 cells/well in 96-well plates 24 h prior to transfection. The transfections of FRET gene reporter plasmids H3K9 and H3K27 was performed with 0.3 μL/well of Lipofectamine® 3000 and 50 ng of plasmid DNA per well. At 24 h post-transfection, cells were treated with 0, 125, 250, and 500 μM of Met, and quantification of histone methylation was performed at 0, 12, and 24 h post-treatment as well as cell viability at 24 h using CellProfiler software. An inverted microscope for live imagining (EVOS Methionine (Met) and lysine  are the Histones are proteins  found in the cell nuclei, and are responsible for packing and arranging the DNA by acting as spools around which the DNA winds and they play a significant role in gene regulation. The functional structure of histones can be modified through several biological processes such as acetylation, phosphorylation, and methylation, among others . RevieweThe S-adenosylmethionine (SAM) is the universal methyl-donor for the multiple types of methyltransferase reactions in the cell , and amoThe potential of using relatively new molecular technologies such as gene reporter technology based on fluorescent proteins in dairy cattle molecular biology has been discussed previously . Lin andBased on the known regulation of histone methylation by Met metabolism in humans , and theg. After centrifugation, pelleted cells were resuspended in 2 mL Resuspension Solution, followed by addition of 2 mL of Lysis Solution, and incubated for 3 min at room temperature. After incubation, 2 mL of Neutralization Solution added, followed by 0.5 mL of endotoxin binding reagent and incubated for 5 min at room temperature. After incubation, 3 mL of 96% ethanol was added, and the solution was centrifuged for 40 min at 4,500 × g to pellet cell debris and chromosomal DNA. After centrifugation, the supernatant (~6–7 mL) was transferred to a new 15 mL tube and mixed with 3 mL of 96% ethanol. This solution was passed through a silica-based membrane column via centrifugation for 3 min at 2000 × g, then the plasmids bound to the membrane were purified with two different wash solutions (I and II). Finally, the purified plasmids were eluted with 350μL of Elution Buffer. Concentration and purity of plasmids were assessed with a Nanodrop ND-1000 spectrophotometer , for which the 260/280 ratio was above 1.9.The cell culture and plasmid purification were performed as previously described in Osorio and Bionaz . In thisIn order to evaluate the effects of Met on histone methylation, MACT cells were transfected with a plasmid DNA that encodes for a modified peptide substrate corresponding to the methylation site of interest within histone tail in H3, and capable of emitting a FRET type signal using cyan and yellow fluorescent proteins. MACT cells were seeded at 30,000/well in 96-well plates 24 h prior to transfection. The transfection reagent used was Lipofectamine® 3000  at a concentration of 0.3μL/well. The final volume per well used was 100μL for all transfection conditions and 50 ng of plasmid DNA per well. The treatments were applied 24 h post-transfection, and each treatment was performed in triplicates in each plate as follow: L-Met  was dissolved in Opti-MEM® to a final stock solution of 50mM, and subsequent dilutions with Opti-MEM® were performed to get the final working solutions: 125μM, 250μM, and 500μM of Met. These treatments were applied to a total of 4 plates performed on different days. In each plate, one of the treatments was seeded cells only incubated with 100 μL of Opti-MEM® to be used as a positive control for viability, and additional treatment of cells incubated with 100 μL of 70% molecular ethanol (diluted with Opti-MEM®) for 20 min at 24 h post-treatment to be used as a negative control for viability.2  was used to take 4 pictures/well at 0, 12, and 24 h post-treatment. For the histone methylation analysis, each picture was an overlay of cyan fluorescent protein  and a fluorescence resonance energy transfer-FRET  detected with the corresponding fluorescent light.After the treatments were applied, an automated epifluorescent microscope for live imaging  equipped with a motorized X-Y scanning stage, LED light engine, and environmental chamber to maintain cells at 37˚C and 5.0% of COThe open-source software CellProfiler  was used to analyze each picture to quantify cell number and intensity of all cells in each picture. The total intensity of cells per image was calculated with the CellProfiler based on cells that expressed both CFP and CFP-YFP fluorescent intensities . Then, a ratio of total intensity of CFP-YFP over CFP was calculated to obtain a YFP signal, which is the signal associated with histone methylation. Live and Dead cells were measured at 24 h post-treatment. Dead cells were measured using a nuclear stain  over a red filter . While live cells were measured using a Hoechst stain  over a blue filter . Cell viability was calculated by colocalizing the number of dead cells over the number of blue cells in a given picture and multiplying the result by 100 , histone methylation , DNA methylation [DNA methyltransferase 3 alpha (DNMT3A) and DNA methyltransferase 1 (DNMT1)], AA transporters , and protein synthesis .The RNA isolation from cell pellets was carried out using the RNeasy Plus Mini Kit , following the manufacturer’s instructions with some modifications. Briefly, prior to the RNA isolation, the cell pellets  was calculated based on data from 4 pictures per well, and data from each picture with the farthest deviation from the mean per well was removed if the CV % was > 5%. Then, the mean per well was used for statistical analysis. The relative histone methylation in H3K9 and H3K27 was analyzed as repeated measures using the PROC MIXED of SAS  with plate, Met concentration, time , and their interaction as the fixed effects in the model. The well nested within plate and treatment was used as the random effect. The relative histone methylation measured at 0 h post-treatment was used as a covariate for the repeated measures analysis. Data measured at 24h post-treatment, including global DNA methylation, gene expression, total protein concentration, and cell viability, the plate and Met concentration were the only variables considered as a fixed effect in the model. In the histone methylation data, two observations in two different plates were considered outliers and removed from the analysis. The P ≤ 0.04) of Met supplementation and time (Met × Time) in K9 and K27 (P < 0.01) histone methylation, while the 0 Met treatment had the lowest (P < 0.01) histone methylation (P < 0.01) in 0 and 250 Met in comparison to 500 Met (P = 0.01) than 500 Met, while 0 and 125 Met treatments had intermediate levels of histone methylation. A treatment effect (P < 0.01) on viability at 24 h post-treatment in K9 and K27  in K9 and k27, and this effect was reflected on a consistent quadratic effect (P ≤ 0.01) in both K9 and K27 over the Met treatments. However, the greatest histone methylation in K9 and K27 was at 125 μM and 250 μM, respectively.Histone methylation analysis at 24 h post-treatment is shown in P = 0.01), which was reflected in a linear (P < 0.01) decreased in global DNA methylation as Met supplementation increased from 0 to 500 μM (P = 0.07) for a Met effect on total protein concentration was observed on Met supplementation, and it was reflected in a quadratic effect (P = 0.07) with the highest total protein concentration at 125 μM  of Met supplementation was not observed on the genes related to the Met cycle. However, a linear upregulation (P ≤ 0.05) of the genes MAT1A and SAHH was observed as Met supplementation was increased from 0 to 500 μM. Similarly to MAT1A and SAHH, a trend for an upregulation on the mRNA expression of the genes PEMT (P = 0.06) and MTR (P = 0.08) was observed as Met supplementation was increased from 0 to 500 μM.Main effect for Met supplementation on genes associated with the Met cycle is shown in SUV39H1 was the only gene with an overall effect (P = 0.04) for Met supplementation, and to a lesser extent DNMT1 (P = 0.06) and SETDB1 (P = 0.07) had a trend for a Met effect. Then, while the Met effect on SUV39H1 and DNMT1 was described by a positive quadratic effect (P ≤ 0.03), the Met effect on SETDB1 as main associated with a linear increase as Met supplementation increased from 0 to 500 μM  to be downregulated when Met supplementation was increased from 0 to 500 μM (P (Main effect for Met supplementation on genes associated with histone and DNA methylation is shown in o 500 μM . In cont00 μM (P ).SLC38A2 gene was the only gene with a Met effect (P = 0.01), and this was attributed to a linear downregulation in its expression as Met supplementation increased from 0 to 500 μM. In contrast to SLC38A2, SLC38A9 had a linear upregulation (P = 0.03) as Met supplementation increased from 0 to 500 μM, and a trend (P = 0.08) for a similar effect was observed in SLC3A2. A trend (P = 0.09) for a positive quadratic effect was observed in RPS6KB1. The Met supplementation did not affect (P ≥ 0.11) the expression of SLC1A5 and MTOR.Main effect for Met supplementation on genes associated with AA transporters and protein synthesis is shown in The application of fluorescent proteins for tracking single molecules in live cells or the whole organism has been vastly exploited and has impacted the fields of biochemistry, biotechnology, and cell biology . In animin vivo studies where hepatic gene expression of MAT1A, PEMT, and SAHH was upregulated in transition dairy cows supplemented with methionine [in vivo or in vitro models.Methionine is an essential amino acid, and its beneficial effects on the performance of livestock animals have been extensively studied. In dairy cattle, such beneficial effects have been commonly attributed to a low abundance of this amino acid in forages and feedstuff normally used in dairy cattle nutrition . Therefothionine , 32. TakSLC38A2 and SLC38A9 were the most responsive to varying concentrations of Met in the media  in the media. This consistent effect on SLC38A2 by Met in MACT cells indicates an underlying mechanism as explained by Dong, Zhou [SLC38A2, in postpartal mammary tissue of transition dairy cows fed a rumen-protected Met supplement. Discrepancies in SLC38A2 response to Met between in vitro and mammary tissue could be related to the Met concentration, as higher Met concentrations were tested in vitro  is essential for the initiation of protein synthesis. Although some AA, such as leucine, are well known for stimulating the activity of mTOR, Met has been observed to have inconsistent effects on mTOR activity, in terms of the ratio of p-mTOR:mTOR –37. SimiBatistel . HoweverBatistel .Methionine is a well-known precursor of s-adenosylmethionine (SAM) , and, inThe results obtained via FRET technology in this study confirmed that Met could alter the histone methylation in H3K9 and H3K27 in immortalized bovine mammary cells . HoweverThe biological significance of histone methylation through Met supply in bovine mammary cells and how this molecular process can affect the overall milk biosynthesis in dairy cows remains unclear. The more evident effect of Met on H3K9 methylation put forth the idea of this lysine residue to be a potential candidate for nutriepigenomic effects via dietary Met or methyl donors in the future.SUV39H1 and SETDB1 as histone methyltransferases is well known, especially for the H3K9 [MAT2A), one of the two isoenzymes that catalyze the synthesis of SAM from Met, suppressed H3K9me3 formation. This effect was associated with the activity of SETDB1 but not SUV39H1 for certain specific genes, such as Ptgs2 [SETDB1 was influenced in part by the linear increase in Met supply. Interestingly, the negative quadratic effect SUV39H1 was contrasting with the positive quadratic effect in H3K9 methylation and total protein synthesis, which might suggest a regulatory feedback mechanism by H3K9 methylation. Taken together, these data suggest that there is a connection between Met availability and transcription of histone methyltransferases, which has been confirmed in other biological models; however, it remains to elucidate the contrasting effect of Met between H3K9 methylation and SUV39H1 in the bovine.The role of the H3K9 , 48. Altas Ptgs2 . Kineticas Ptgs2 . In the CSN1S1 (αS1-casein) in mammary tissue of pubertal heifers or culled non-lactating cows when compared to lactating cows [SAHH , among others. The histone methylation data suggest that, to some extent, methyl-donors such as Met may affect the methylation sites, H3K9 and H3K27, and consequently causing a different epigenetic alteration . Gene exS1 File(DOCX)Click here for additional data file.