This study analyzed the fundamental properties of concrete using steel slag, to test its viability as an aggregate material. An experimental investigation into the effect of steel slag as a coarse aggregate, and heavyweight waste glass as a fine aggregate, on the drying shrinkage of concrete was performed. The calculated shrinkage strain was compared to five different shrinkage prediction models, namely, the ACI 209, B3, KCI 2012, EC 2 and GL 2000 model codes, to evaluate their ability to accurately predict shrinkage behavior. From the results, the elastic modulus of concrete increased with the increase in steel slag substitution ratio, however drying shrinkage decreased. The predictive value of the existing prediction model of drying shrinkage differed from the experimental values, and requires correction to improve its accuracy. The B3 model code showed the best prediction results of drying shrinkage. Concrete is composed of cement, mixing water, and aggregates which constitute approximately 80 percent of the total mass . Increas2, stabilizing it. Aging the steel slag in water can significantly reduce the aging period [Korea is the fifth largest producer of steel in the world, and generates a large amount of steel slag. Steel slag is an industrial waste and is obtained as a by-product during the production of steel . Extensig period .Drying shrinkage is defined as a volume change due to the drying of concrete; it affects the stability of concrete, and is dependent on the properties of concrete-making materials and mix proportions ,25. TherAs described above, the mechanical properties and the durability of concrete (mortar) using heavyweight waste glass as fine aggregate were investigated. The results show that heavyweight waste glass can be used to reduce the drying shrinkage . This isConsequently, the objective of this paper is to experimentally investigate drying shrinkage in a concrete specimen using heavyweight waste glass and a substitution ratio of steel slag. Furthermore, we compared the experimental values of drying shrinkage to the predicted values from existing models.In this study, ordinary Portland cement  was used in all the concrete specimens. To investigate the effect of mineral admixtures on drying shrinkage, parts of the cement was replaced. These were fly ash  and blast furnace slag . The physical and chemical compositions of the binders are shown in Crushed gravel was used as a coarse aggregate with a maximum aggregate size, Gmax, of 20 mm. The specific gravity and absorption ratio of the coarse aggregate were 2.68% and 0.97%, respectively. Furthermore, the material properties of coarse aggregate were measured according to ASTM C 127  and ASTMHeavyweight waste glass has a specific gravity of 3.0 and fineness modulus of 3.4. It was crushed by a jaw crusher for use as fine aggregate in concrete. Furthermore, only the crushed heavyweight waste glass that could pass through a 5 mm sieve was used, and the material properties of heavyweight waste glass were measured according to ASTM C 128  and ASTMSteel slag obtained in Korea was tested to investigate its suitability for use as coarse aggregate in concrete. The steel slag particles exhibit an angular shape, sharp edges and a porous surface texture, as presented in Meanwhile, before using steel slag as coarse aggregate in concrete, its mechanical properties should be considered. This study is executed various mechanical property tests on steel slag, and the results are presented in In particular, to use steel slag as the aggregate in concrete, an expansion test of steel slag must be performed. The immersion expansion ratio of steel slag must be below 2% to satisfy the required specifications . To measFrom the test results, the immersion expansion, density, and unit weight volume satisfied the specification value. However, the absorption ratio of steel slag was higher than the limit regulated by KS F 2527 , due to To investigate the drying shrinkage of concrete using steel slag as the coarse aggregate with different substitution ratios, the length change test was carried out for the concrete specimen. Heavyweight waste glass was used as the fine aggregate. The test variables and methods are listed in In general, concrete needs a water-to-binder ratio of 35–55% to facilitate the mixing and to maintain its workability. Above all, based upon considerable experiments in a laboratory setting, in this study, the water-to-binder ratio of the specimen is fixed at W/B 45%. For the evaluation of the properties of the concrete, steel slag was used as a substitute for coarse aggregate at 0%, 50%, and 100% by volume. The mix proportions for the concrete specimens used in this study are shown in To investigate the fresh properties of the concrete, the slump and air contents were measured. The slump and air content experiments were executed in accordance with ASTM C 143  and ASTMFor the compressive strength test, the specimens were prepared based on ASTM C 39 . The comThe drying shrinkage of the concrete specimen (dimensions: 100 mm × 100 mm × 400 mm) was measured according to the procedures presented in ASTM C 157 . Each drThe test results of slump and air content are shown in The results for the compressive strength of concrete, which is a typical factor for the prediction of drying shrinkage, are shown in The results of the elastic modulus test on the concrete substituted with steel slag and heavyweight waste glass are presented in The test results of the drying shrinkage of concrete with steel slag as the coarse aggregate and heavyweight waste glass as the fine aggregate are shown in The drying shrinkage of all specimens increases dramatically initially, and continues to increase up to the first 50 days of the curing period. In the later stages of the curing period, drying shrinkage slows down considerably and proceeds at a gradual rate.The process of drying shrinkage is caused by the evaporation of water by hydrostatic tension from the small capillary pores of the cement paste and the adsorbed water from C-S-H . The cemThe drying shrinkage of the concrete specimen with steel slag as the coarse aggregate is reduced regardless of the type of mineral admixture, by approximately 4.2–16%, as compared to a substitution ratio of 0%, because the increased density due to steel slag is an important factor that influences drying shrinkage reduction [In contrast, since the drying shrinkage of concrete depends on the absorption of the aggregate, the high absorption of steel slag increases the drying shrinkage. However, the overall effect of substituting steel slag is a decrease in drying shrinkage, since it is more affected by the higher density than the higher water absorption of steel slag. Furthermore, as previously noted, using heavyweight waste glass as the fine aggregate in concrete reduces drying shrinkage because of the low water absorption of the glass. Therefore, using heavyweight waste glass and steel slag as fine and coarse aggregate, respectively, can reduce the drying shrinkage in concrete specimens.Drying shrinkage gradually occurs over a relatively long time, making it difficult to measure. There are several drying shrinkage prediction models based on experimental results, each requiring many parameters. In this study, five prediction models were selected to compare the experimental results with the prediction results of concrete specimens using steel slag as coarse aggregate and heavyweight waste glass as fine aggregate. The parameters required for the prediction of drying shrinkage in concrete by these models are tabulated in As shown in As previously noted, drying shrinkage is strongly influenced by the properties of the coarse aggregate in concrete . HoweverThe selected prediction models were ACI-209R , Euro coThe accuracy of the prediction models of drying shrinkage were in the order of B3 > ACI > KCI 2012 > GL 2000, regardless of the mineral admixture type in the initial curing stage (first 30 days). However, in the case of the EC 2 model, the predicted value of drying shrinkage after 100 days does not increase significantly when using OPC as the binder, as it uses compressive strength over long term age (91 days). As the increase in compressive strength with the OPC binder at 91 days was not greater than that with the mineral admixtures, the predicted vales of drying shrinkage converge to a certain level. Furthermore, since the EC 2 and KCI models are based on the CEB-FIP model, their predicted values of drying shrinkage are similar.The GL 2000 model shows the highest variation from the experimental results, since it is based on actual structure and is distinctly influenced by V/S (volume surface ratio), compared to the other models. Consequently, the predicted values of drying shrinkage increase with the decrease in the size of the concrete specimen.Unlike the other prediction models, the GL 2000 model considers the elastic modulus of the concrete specimen. However, the influence of compressive strength and V/S further increases even if the elastic modulus is taken into consideration. Consequently, the decrease in drying shrinkage due to the increase in the elastic modulus of the concrete specimen is reflected. Therefore, to effectively predict the drying shrinkage of concrete, the existing prediction models require corrections.(1)When steel slag is used as the coarse aggregate in concrete, drying shrinkage decreases with the increase in the substitution ratio of steel slag, since it is affected more by the higher density than the higher water absorption of steel slag. Thus, steel slag can be used to reduce drying shrinkage in concrete.(2)The existing prediction models do not effectively predict the drying shrinkage that is affected by the properties of the aggregate, and need to be corrected for concrete using steel slag as the coarse aggregate and heavyweight waste glass as the fine aggregate.(3)The B3 model best predicts the drying shrinkage because it reflects various material properties such as moisture content, compressive strength and binder content. In contrast, the GL 2000 model predicted distinctly different results compared to the other prediction models.(4)When steel slag is replaced as the coarse aggregate of concrete, the elasticity modulus can be improved, due to the high density of steel slag, by approximately 14.7–42.3%, as compared to a substitution ratio of 0%.(5)Conclusively, to effectively predict the drying shrinkage of concrete specimens using industrial waste aggregates, a correction of the existing prediction model is required.The test measurements and comparisons of the prediction models for the drying shrinkage of concrete using industrial waste as aggregate were examined. The conclusions obtained from this study are given below:


Space trusses are structural systems, generally made of tubes, used worldwide because of their advantages in covering long-span roofs. In addition to having a low cost, the truss weight is relatively reduced. The load capacity of these structures depends also on the strength of their node connection. Connections made with the superposition of flattened tube ends trespassed by one bolt are, generally, known as typical nodes. They are inexpensive but present eccentricities that reduce significantly the strength of such space trusses. To increase the truss load capacity, this research presents the results of an experimental program to reduce the eccentricities of the typical nodes. This reduction is done with a new type of spacer made of encapsulated concrete with steel fiber or sisal fiber. The experimental tests showed that the trusses with typical nodes collapsed under reduced load by local failure due to high distortions at the nodes. The trusses with encapsulated concrete spacer showed good results, with an increase in collapse load of 36% and failure by buckling bars. Space trusses are three-dimensional (3D) reticulate systems used worldwide because of their advantages in covering large, free spaces. In addition to having low cost, the weight itself is relatively reduced. Space trusses are versatile in a range of applications, from small ornamental marquees, the cover of warehouses, gymnasiums, hangars, and shopping centers, to helipads, etc.Space trusses were copied from nature. The natural elements always seek to minimize stress and maximize strength in an efficient way, taking advantage of the load capacity of all members of the body ,2. The nHumans were quick to copy examples from nature. Examples of three-dimensional modular structures, produced on an industrial scale, were initiated by scientist Alexander Graham Bell ,7,8,9,10MERO system in 1943, considered to be a connection of simple execution. It is because Bell’s connection system was complex. MERO connection was widely used commercially and was developed in Germany by Dr. Ing. Max Mengeringhausen and Rohbauwwise [It was a structure made up of modular tetrahedral elements prefabricated in a factory and attached to the construction site with screws . The strbauwwise ,16,17,18MERO connection, several other systems were patented with the same principle: Steel ball, hexagonal screw, connection sleeve, and hollow section bar. The connection system with spherical nodes showed satisfactory results in experimental tests, mainly because bending moments were not mobilized in the connection. The assembly system is theoretically simple, using only a torque wrench to tighten the bolt [After the invention of the the bolt ,19,20,21VESTRUT system was widely used as a space truss connection option [In this context, the first typical node connection used as an economic alternative in the project was in 1960 in the United States by Richard Fuller and Konrad Wachsmann in the construction of a hangar cover at London airport see a. Later n option   and 2E, vertical (distance between points A and B (see 2E), using a spacer element. In this case, it is observed that the eccentricity correction 2E is made using an element that provides the distance d equal to 2E between the diagonals and the bottom chord. Thus, points A and B . The pr A and B a can be  A and B b.2E is proportional to the angle ϕ, being equivalent to the correction distance d. 2d is equal to 15t of the pipe wall thickness (flange) 1t plus 23t of the pipe wall thickness of the diagonal 2t. Considering the wall thicknesses of the same tubes , we have a total of 8t.The vertical eccentricity 1E side, and the second triangle composed by the base of the D side. Equating the two triangles, Equation (1) is obtained.1E Eccentricity due to flattening of the bar; 1t and t2 is the thickness of the tube; H represents the height of the truss; L the length of the chord; d is the spacer thickness necessary to correct the eccentricity 2E. However, the use of this equation requires that the spacer has sufficient resistance to support the compression force. Thus, concrete is a candidate to be used as a spacer due to its good resistance to compression. Nevertheless, to avoid concrete cracks, two fiber mix options were evaluated. One option was concrete mixed with steel fiber and the other was concrete mixed with sisal fiber. Both concrete mixtures can be encapsulated by cold-formed steel profiles to restrain concrete deformation. The concrete spacers have the function to eliminate eccentricity 2E  [In the context of the civil construction environmental impact, fibers from natural resources, such as sisal fiber, appear as an alternative to synthetic fibers. However, the elements incorporating such technology are still on the market . The sisf = 1%) ,105,106.To obtain a homogenous concrete mix with sufficient workability, all batching was done by weight. The concrete was mixed with an electrical mixer see a. The inThe materials were mixed until a uniform color was obtained. After that, half of the water quantity was added and mixed for several minutes, too. After 5 min beating, finally the rest of the water quantity was added to the mixture and mixed for about 3 min. When steel fiber and sisal fiber were added to the mix, they were uniformly distributed in the layer top of the mixer.After mixing, the workability test was carried out with a slump test before the fresh concrete was poured into the spacer molds. The average workability of concrete without fiber and with fiber was around 10 cm see b,c. The After that, the surface of the concrete was leveled off. Then, the specimens were covered to prevent water evaporation. After 24 h, the specimens were taken from the molds and placed for 7 days in a tank, and then for 28 days cured in water with 23 °C temperature and humidity of 76%.This study performed a four-point bending test for the determination of the tension softening properties and curves of concrete with and without fiber. For each concrete mix, shown in After the completion cure of concrete and prior to the test, each beam specimen was cut with a notch located at mid-length of the beam. The notch was set with a constant width of 4 mm see a. A WDW-Due to the bridging mechanism of fibers, concrete with fiber can provide superior performance, especially under tension, as compared to concrete without fibers. The mechanical properties of the reinforced concrete with steel and sisal fibers are in It was observed that for the three types of concrete tested the one with steel fiber presented the best behavior in the bending and compression tests. The analysis of the tenacity showed that concrete with steel fibers reinforcement presented a superior behavior compared to the concrete with sisal fiber and without fiber. However, the concrete with sisal fiber showed workability difficulties during the execution of the specimens. In this way, the spacers were built with concrete with steel fiber. For this, two spacers were built: One just with the concrete with steel fiber and the other one concrete with steel fiber but encapsulated by a steel cold-formed profile. 2E . Each truss specimen, with spacers applied at each typical node for correcting eccentricity E2 see , used 56E2 see f. To staE2 see e, where E2 see b occurreThe five experimental tests evaluated the load capacity of the space truss, using 4 LVDT with a progressive load rate of 0.20 kN/min and using the HBM Catman system. The five tests compared displacements and collapse loads of space trusses. Two experiments were done with trusses with typical connection without spacer. Two experiments were done with space trusses with typical connection corrected with spacers made of encapsulated concrete with steel fiber, and two experiments were done with spacers with the same concrete with steel fiber but not encapsulated.E2  Two trusses with typical connection and no correction of the eccentricities, (2) one truss using spacers of concrete not encapsulated, just with steel fiber concrete, (3) two trusses with typical connection using spacer of encapsulated concrete mixed with steel fiber. The tests showed that:


We aimed to assess the knowledge and understanding of antibiotic use and resistance in the general population of Cyprus, in order to inform future antibiotic awareness campaigns with local evidence. Cross-sectional survey following the methodology of the “Antibiotic resistance: Multi-country public awareness survey” of the World Health Organization, during December 2019–January 2020. A total of 614 respondents participated: 64.3% were female and most were aged 35–44 years (33.2%) or 25–34 years (31.8%). One-third had used antibiotics >1 year ago and 91.6% reported receiving advice on appropriate use from a medical professional. Despite high awareness on correct use of antibiotics, lack of knowledge was noted for specific indications, where approximately one-third believed that viral infections respond to antibiotics and 70.7% lack understanding of how antibiotic resistance develops. Higher education graduates exhibited significantly higher knowledge rates. As high as 72.3% were informed about “antibiotic resistant bacteria” from healthcare professionals or social media. Most agreed on the usefulness of most suggested actions to address antibiotic resistance, with higher proportions acknowledging the role of prescribers. Up to 47% could not identify their role in decreasing antibiotic resistance. Our study provides local evidence to inform future efforts in a country characterized by high antibiotic consumption rates. Recent and inappropriate use of antibiotics are well established risk factors for infection with resistant bacteria ,2. ConseIn 2018, the European Commission conducted a repetitive Eurobarometer survey on the knowledge, attitudes and behavior of the public towards antibiotic use and after having developed guidelines on sensible use of antimicrobials in human medicine in 2017 . AlthougIn Cyprus, results from local surveillance of antimicrobial use and resistance are limited to international studies. According to recent surveillance reports , Cyprus The purpose of the current study is to investigate in detail the level of understanding, knowledge and common behaviors related to antibiotic use and antibiotic resistance in the general public of Cyprus, aiming to guide future efforts to improve the effectiveness of awareness campaigns and enhance optimal measures to improve antibiotic use in the community.During the study period, a total of 614 respondents completed the survey  and the majority were between the ages 25–44 (65%). Among responses, 283 (46.1%) were completed during face-to-face interviews and 331 (53.9%) were completed online. Most were residents of urban (63.4%) or suburban areas (22.8%) and 13.8% lived in rural areas. The majority of participants were Nicosia residents (49%), followed by residents of Limassol (19%), Larnaca (17%), Famagusta (8%), and Paphos (7%). University/college graduates and master’s degree holders represented 79% of participants.Concerning household composition, most were married adults, either with at least one child (24.8%) or without children (21.7%). Household with one adult was also common (31.1%), with less frequent being multiple adults (10.3%) or multiple adults with at least one child under 16 (6.5%). Details on demographics of participants are presented in A total of 194 of responders (32%) received their last course of antibiotics within 6 months and the majority (87%) reported they received their prescription from a doctor. As high as 91.6% received advice on how to take their course of antibiotics by either a doctor, a nurse or a pharmacist. Additionally, 96.3% of responders took their antibiotics from a pharmacy store. No differences were detected in recent antibiotic use when comparing gender, level of education, and urbanization between respondents.Among respondents, 87% stated that they know they need to take the full prescription of antibiotics and 79.6% stated that it is not acceptable to use the same antibiotics taken from a family member or friend with the same symptoms.Misconception was recorded when respondents were shown the statement “It’s acceptable to buy the same antibiotics, or request these from a doctor, if you’re sick and they helped you get better when you had the same symptoms before”, where 25.4% incorrectly agreed.When participants were asked to select which medical conditions can be treated with antibiotics, 81% and 61.9% correctly identified bladder/UTI and skin/wound infections, respectively. In contrast, 36.6% and 30.0% incorrectly chose the common cold/flu and sore throat respectively, as conditions that require antibiotic treatment. Indication for treatment of gonorrhea with antibiotics was correctly selected by only 23.1% .No differences were detected regarding knowledge on appropriate antibiotic use between gender, urbanization, level of education, and household composition.Concerning basic knowledge of antibiotic resistance terms, 21.2% of respondents stated that they had never heard any of the terms: “antibiotic resistance”, “antimicrobial resistance”, or “antibiotic-resistant bacteria”. The phrase known best by 72.3% of respondents was “antibiotic-resistant bacteria”, followed by “antibiotic resistance” (55.6%) and “antimicrobial resistance” (33.7%). Among respondents who had heard these terms before, approximately one-third stated they had heard them from a doctor/nurse or the social media.p < 0.001) and by residents of urban regions compared to suburban and rural residents (p = 0.024) (p = 0.005), whereas they wrongly believe that only people that use antibiotics regularly are at risk of antibiotic resistance (p = 0.019).To explore the level of understanding of antibiotic resistance, respondents were presented a list of statements and asked whether these were true or false, or their level of agreement. Overall, the majority of respondents correctly identified most statements about antibiotic resistance and how to address it. A frequent misconception was detected regarding the statement that the human body becomes resistant to the antibiotics and not the bacteria themselves, where 70.7% incorrectly identified it as a true statement. Knowledge-based questions were answered correctly to a higher level by tertiary education graduates compared to secondary education graduates (= 0.024) . In addiRegarding perceptions towards antimicrobial resistance, participants exhibited a high level of agreement in the majority of statements . On the Participants in their majority agreed that everyone needs to use antibiotics responsibly (92.8%) and are worried on the impact this problem will pose on their health and family (76.4%). Misconceptions were identified when they were asked about the impact of antibiotic resistance and about their role in addressing this issue. Specifically, 52.3% believe that medical experts will solve the problem of antibiotic resistance before it becomes too serious and as low as 63.4% include antibiotic resistance among the biggest problems the world faces. Respondents also believe that if they use antibiotics correctly, antibiotic resistance will not be an issue for them (47.6%), and that there is not much that people can do to stop antibiotic resistance (42.5%) . QuestioRecent surveillance reports highlight that Cyprus has a high prevalence of antibiotic-resistant bacteria, as well as a high overall consumption of antibiotics ,10,12. TOptimization of antibiotic use in healthcare requires a national strategy with specific priorities and with participation of different stakeholders involved in antibiotic use, such as prescribers, pharmacists, patients, and healthcare organizations. A minimum set of knowledge and competences in microbiology, infection pathogenesis, prescribing, and stewardship, is necessary for prescribers in order to ensure safe and responsible antibiotic use . In addiCompared to the corresponding World Health Organization (WHO) multi-country survey , CypriotIn line with the findings of previous surveys that followed the same methodology ,21,22,23Notably, tertiary education graduates exhibited significantly higher levels of understanding of such statements, further supporting the role of education in improving understanding of basic antibiotic resistance concepts. This is also confirmed by previous studies that included university students from various countries, who showed high levels of knowledge ,26,27. IΑdults with children displayed higher level of understanding in statements assessing attitudes towards antibiotic resistance. This is an interesting finding since parental knowledge and misconceptions have been identified as major contributors for unnecessary antibiotic use in children . The incThe majority of respondents in our study agreed that almost all proposed actions could help address the problem of antibiotic resistance, particularly for statements signifying the importance of receiving antibiotics only when prescribed by healthcare professionals. This again is in agreement with other observations of our survey and the Eurobarometer findings, showing that a significant proportion of respondents take antibiotics only by prescription . In contThe results of our study should be interpreted in the context of certain limitations. Some information and sampling bias might be owed to geographic distribution, due to low percentage of rural residents (13.8%), which was due to lower accessibility to the survey. Despite the fact that responses were collected from all government-controlled districts, slightly higher proportion of responses from Nicosia and lower from Limassol were noted, compared to the population of each district . GeograpAs for population representativeness, compared to the previous studies that followed the WHO methodology, the number of respondents is considered far more representative of the total population of the Republic of Cyprus  ,22,26,29https://apps.who.int/iris/handle/10665/194460).The present study adapted the methodology of the WHO “Antibiotic Resistance: Multi-Country Public Awareness Survey” . This su® forms survey , the questionnaire was developed in Greek, back-translated, pilot-tested with five persons and adjusted appropriately. It was available on paper for face-to-face interviews or online as a prepared Googles survey .The questionnaire comprised of 7 multiple-choice questions requesting: gender, age, city of residence, urbanization, education, income and household composition and 35 questions regarding knowledge and perceptions about antibiotic use and antibiotic resistance. Of those 35 questions, 11 were multiple-choice, 10 were true/false, and 14 were Likert scale questions.® forms document, which was sent personally via social media after the purpose was again explained. A reminder for completion was sent two days later. All questionnaires given or sent were answered and all questionnaires were included regardless of degree of completion. Questionnaires were given in all five districts of the government-controlled areas of the Republic of Cyprus: Nicosia , Limassol , Larnaca , Paphos , and Famagusta  [The study was performed from 21st December 2019 until 31st January 2020. Respondents from around Cyprus were invited to complete the survey in public areas such as cafeterias, shopping malls and other, where the primary study researcher approached the participants and after explaining the purpose of the study, they agreed on completing it. The survey was also available online as a Googleulation) .Participation was voluntary, anonymous and without compensation. Informed consent was stated on the first page. To minimize methodological bias, participants were asked to self-complete the survey.Cyprus residentsAdults > 16 years’ oldNon-healthcare professionalsParticipants were eligible to complete the survey if they were:Descriptive statistics were used for quantitative parameters. Unanswered questions were included in the results as ‘not answered’. Data are presented as counts (%) for categorical variables. Potential associations of knowledge, attitudes and perceptions with participants’ gender, level of education, urbanization, and household composition were assessed using the Chi-square test or Fisher’s exact test. Statistical significance was set at 5%. Data were processed and analyzed using GraphPad Prism version 8.0 for Windows .To our knowledge, this is the first survey to specifically assess knowledge, understanding and attitudes of the general public in Cyprus towards antibiotic use and antimicrobial resistance. Despite a high degree of understanding, areas for improvement were detected, including knowledge of indications of antibiotic use, mechanisms leading to antibiotic resistance, and the need of a multifaceted approach to combat resistance. These results will inform future engagement efforts to ensure data-driven campaigns and community stewardship programs, aiming to improvement of the quality of healthcare in a country characterized by high antibiotic consumption rates.


Antimicrobial resistance (AMR) is considered a rapidly growing global public health emergency. Neonates and children are among patients for whom antibiotics are largely prescribed and for whom the risk of AMR development is high. The phenomenon of increasing AMR has led to the need to develop measures aimed at the rational and effective use of the available drugs also in children and antimicrobial stewardship (AS), which is one of the measures that in adults has showed the highest efficacy in reducing antibiotic abuse and misuse, appears as an attractive approach. The aim of this manuscript is to analyze the basic principles and strategies of pediatric AS. To this end, we searched in PubMed articles published in years 2000 to 2019 containing “antimicrobial resistance,” “antibiotic use,” “antimicrobial stewardship,” and “children” or “pediatric” as keywords. Our review showed that the balance between multi-resistant organisms and new antimicrobials is extremely precarious. The AS tools are the most important weapon at our disposal to stem the phenomenon. Careful monitoring of prescriptions, continuous training of prescribing physicians and collaboration with highly qualified multidisciplinary staff, creation of local and national guidelines, use of rapid diagnostic tests, technological means of support, and research activities by testing new broad-spectrum antibiotics are mandatory. However, all of these measures must be supported by adequate investment by national and international health organizations. Only by making AS daily practice, through the use of financial resources and dedicated staff, we can fight AMR to ensure safe and effective care for our young patients. Antimicrobial resistance (AMR) is defined as the ability of a microorganism  to prevent an antimicrobial from acting against it . AntibioHistorically, in the early stages of the antibiotic era, the rapid availability of new drugs made new therapies readily available to treat different infectious processes . However, rapid antimicrobial development has a cost: AMR because of high prescription rates of antimicrobials . At the AMR is considered a rapidly growing global public health emergency, both for epidemiological and economic reasons, to such an extent that the World Health Organization  has publNeonates and children are among patients for whom antibiotics are largely prescribed and for whom the risk of AMR development is high . The pheAntibiotics are among the most widely prescribed medications among children in both hospitals and the community. According to data from ARPEC Study Group, the most frequently treated disease in children is bacterial infection of the lower respiratory tract (18.7%) . In all Clostridium difficile infections  in 50% of cases . This prfections . In 2019fections . Interesfections . They shThe problem of AMR is also related to the large use of prophylaxis of infections in patients suffering from chronic diseases or undergoing surgery. The prophylactic use of antibiotics to prevent infections is controversial. Versporten et al. analyzed data on the prescription of prophylactic antibiotics from the ARPEC-PPS project : most prC. difficile pathogen. They suggested large-scale, well-controlled studies on the use of antimicrobials through sophisticated epidemiological methods, typing of molecular biological organisms, and precise analysis of the mechanism of resistance in order to prevent and control this emerging problem  in 2016, have emphasized the importance of AS in pediatrics and recognized pediatrics as a priority area for further research and activities .Among the reasons why it is so important to create a specific program for the pediatric patient is the heterogeneity in age and weight, which makes it difficult to apply a generic AS program, such as the adult one, given the lack of a standardized method to quantify the use of antibiotics in children. For example, one of the most widely used units of measurement for adults is the “defined daily dose” (DDD) introduced in the early 1980s by the WHO to measure the use of antibiotics in a standardized manner; however, the DDD is not easily applicable in pediatrics since it does not take into account the variability of dosage applied to weight . MoreoveTo promote effective interventions and thereby optimize the use of drugs, it is important to collect information on the current situation regarding the use of antibiotics in all countries. Data collection is necessary to provide a comprehensive and reliable picture of antibiotic use; however, it is often incomplete and fragmented. Hospitals are excellent places to assess antibiotic prescription modalities, given the high concentration of patients with different diseases: this often creates a high selection of bacteria due to the wide spectrum and quantity of antibiotics used, contributing to the development of antibiotic resistance. In most countries of the world, regular monitoring of antibiotic prescription data is not possible due to the high workload and lack of available resources. A viable alternative is to collect data at a specific point in time through the methodology of the point prevalence survey (PPS) . The PPSHistorically, the first PPS projects have been conducted mainly on adults, providing minimal data on hospitalized children. For example, at the European level, the European Surveillance of Antimicrobial Consumption (ESAC) conducted three studies on the use of antibiotics in hospitals: in 2006 (ESAC-1), 2008 (ESAC-2), and 2010 (ESAC-3); however, the methodology used was not specifically designed for infants and children. With the objective of optimizing antimicrobial prescription in children, ARPEC conducted a PPS between 2011 and 2012 on the use of antimicrobials in hospitalized children, standardizing collected data based on age, sex, weight (at birth), basic diagnosis, antimicrobial agent, dose, and prescription indication . In addition, the following subdivisions according to the type of department were considered: neonatology, general pediatrics, specialists , and neonatal and pediatric intensive care (NICU and PICU) . ThroughPPSs have progressively included an increasing number of nations worldwide: ESAC-1, which has collected data from 20 hospitals in 20 different European countries, has developed into the ambitious project of a global PPS. A global PPS pilot project started in 2014, collecting data from infants, children, and adults in one day from 335 different hospitals in 53 countries, as follows: Europe ; Africa , Asia , the Americas  and Oceania . These analyses have been repeated annually since 2017, taking further into account seasonal and geographical variability . HoweverIn conclusion, repeated PPSs should be part of the pediatric management of antibiotics, as they represent a strategy to identify prescription trends over time, to assess the efficacy of AS and to address the problem of inappropriate antibiotic use, with particular regard to dosage. However, it has been shown that PPS alone is not enough to produce changes in clinical practice if they are not supported by other AS methods .In March 2017, the WHO Essential Medicine List (EML) created three subcategories of antibiotics  within the EML for children (EMLc) to facilitate the selection and monitoring of the correct antibiotic and to support AS. The first group is GROUP “Access” (green) includes antibiotics with broad spectrum activities that show a lower resistance potential than those contained in the other 2 groups. Antibiotics in this group should be used as first choice or as an empirical second choice treatment for the most common infections. The second is GROUP “WAtch” (yellow) that includes antibiotics with a broader spectrum but showing a higher resistance potential and should therefore be subject to priority local and national management and monitoring programs. They are used in first- or second-choice empirical treatment in a limited number of specific infectious diseases. The third is GROUP “REserve” (red) that includes antibiotics and classes of antibiotics that should be used for the treatment of confirmed or suspected infections due to multiresistant organisms, where all alternatives have failed or have not proven suitable . In 2019Among the interventions of AS proposed for proper management of antibiotic therapy are pre-prescription authorization (PPA) and post-prescription feedback review (PPRF).In the PPA approach, some antibiotics have restricted indications, and their prescription by clinicians must be previously approved by highly qualified personnel  . The advWith regard to PPRF, AS team members re-evaluate prescriptions and provide recommendations to physicians regarding the possibility of continuing/modifying/suspending treatment based on clinical-laboratory data . Among tBoth of these approaches are valuable tools for AS enhancement, and over the years, several studies have tried to demonstrate which of the two is superior: Mehta et al. compared them in a study in a third-level hospital and found that the switch from PPA to PPRF was associated with a significant increase in both antimicrobials subject to authorization and the number of all antimicrobial agents included in the list of those who required authorization . Among tAs for the method to be preferred, there are conflicting results in the literature. However, Chan et al. performed a further study in which they defined the impact of the PPA method on the use of vancomycin in a third level pediatric hospital and showed that, compared to the previous 3 years of use of the PPRF method, the addition of the second method did not significantly change the antibiotic administration . Two othThe inadequate prescription of antibiotics is often the result of poor education of clinicians, lack of appropriate guidelines, and lack of theoretical-practical training. Education is therefore considered a key point in AS programs and should include structured doctors and trainees, pharmacists, nurses, and students . In factAmong the most recent methodologies is blended learning, a mix of online and face-to-face lessons, which is becoming increasingly popular among students . TraditiThe usefulness of education and application of the guidelines has been demonstrated in many studies. Cisneros et al. demonstrated how the implementation of local guidelines on common infectious diseases combined with adequate training of clinicians in a tertiary center including pediatric patients improved the appropriateness of antibiotic treatment by 26.6% and was at the same time optimally accepted by clinicians . RecentlRegarding diagnostic algorithms, pediatric studies have demonstrated the utility of an algorithm based on a procalcitonin (PCT) cutoff value for guiding antibiotic administration in community-acquired pneumonia (CAP), showing that this approach can significantly decrease antibiotic prescription and antibiotic-related adverse events in pediatric patients with uncomplicated disease .Evidence-based guidelines and diagnostic algorithms appears a useful tool of AS. The guidelines are developed in specialized university centers, where both staff and adequate resources are available, or within Scientific Societies. However, for an optimal application, it is necessary to have a wide diffusion, including first-level centers and emergency departments with non-specialized pediatric personnel.A further proposed AS technique was antibiotic rotation: antibiotics are withdrawn from intrahospital use for a period of time—to limit the appearance of resistance—and are reintroduced afterwards. This is a structured way of introducing heterogeneity of antibiotics into prescribing practice, as heterogeneity, contrary to the restriction of availability, is the most likely way to reduce the appearance of antibiotic resistance .The studies on this practice actually proved to be discordant: in 2002, Moss et al. performed a pilot research to define the safety effects of antibiotic rotation to decrease colonization and infection with antibiotic-resistant bacteria; the study was conducted in a 16-bed pediatric intensive care unit on critically ill children requiring antibiotic treatment. Three classes of antibiotics were rotated at 3-month intervals for 18 months. The broad-spectrum empirical antibiotic cycle was found to be safe and did not increase antibiotic resistance. The study concluded that antibiotic rotation could therefore be a safe and viable strategy to minimize antibiotic resistance in intensive care units . In the Diagnostic uncertainty may lead to inappropriate antibiotic prescription. In addition, antibiotic therapy initiated on suspicion of a bacterial infectious disease is empirical until the microbiological tests results are available, which often requires prolonged periods of time. Empirical therapy is more complex in the pediatric field than in the adult field, considering the different etiology of infections according to age. A rapid diagnostic test (RDT) provides a result in advance of conventional methods used to identify pathogenic microorganisms .Streptococcus pyogenes in pharyngitis  refers to the process of entering and sending instructions from prescribing physicians, including medication orders, laboratory tests, and radiological examinations Children are particularly vulnerable to medication errors for multiple reasons: use of doses based on weight or body surface area, increased sensitivity to medication errors, and variable ability to metabolize and excrete drugs. CPOE can reduce the error rate and improve patient safety. In addition, CPOE technology often includes clinical decision support tools that can automatically verify drug interactions, drug allergies, and other potential problems. By enabling suppliers to send orders electronically, CPOE can facilitate the rapid communication of drug orders and laboratory and radiology reports to pharmacies, laboratories, and radiology facilities, saving time and improving efficiency. Finally, CPOE can facilitate the reimbursement of expenses if integrated with a practical electronic management system . The stuOne of the methods to optimize the use of antimicrobials and improve clinical outcome is therapeutic drug monitoring (TDM) . TDM is TDM is indicated for concentration-dependent antibiotics, e.g., vancomycin and aminoglycosides, when used for at least 3 days  and ofteAlthough all the methods mentioned above can be used in outpatient setting, AS interventions on outpatients are less frequent. Indeed, the few studies conducted show that AS can be effective in reducing the misuse of antibiotics even in outpatient clinics, but with less relevant results than those conducted in a hospital environment . Among sClostridium difficile infections. Antibiotics were prescribed for acute respiratory tract infections, including rhinosinusitis, acute otitis media, pharyngitis, viral upper respiratory tract infection, bronchitis and bronchiolitis, asthma and allergy, influenza, and bacterial or viral pneumonia. The highest prescription rate was reported among pediatric patients under 2 years of age, and the most prescribed antibiotics were penicillins, macrolides, and cephalosporins. The study lists many factors that lead the doctor to prescribe antibiotics incorrectly, some of them unrelated to the clinical aspect   . Anotherillness) . Respondillness) . PhysiciDecision fatigue resulting from the doctor's workload can also contribute to inappropriate antibiotic prescription: it often takes less time to prescribe an antibiotic than to provide a lengthy explanation as to why it is not necessary .In addition, specific diagnostic tests to discriminate whether the infection is of viral or bacterial origin are not always available . In 2016The problem of AMR in both hospital and community settings represents a global emergency in terms of individual health and health care costs. The balance between multi-resistant organisms and new antimicrobials is extremely precarious. The AS tools are the most important weapon at our disposal to stem the phenomenon. The AS strategies conducted on adult patients have had a positive impact; only recently have they been undertaken in the pediatric field, where targeted interventions are needed, considering the heterogeneity in age and weight of patients. Careful monitoring of prescriptions, continuous training of prescribing physicians, and collaboration with highly qualified staff, creation of local and national guidelines, use of RDTs, technological means of support, and research activities by testing new broad-spectrum antibiotics are mandatory. However, all of these measures must be supported by adequate investment by national and international health organizations. Only by making AS daily practice, through the use of financial resources and dedicated staff, we can fight AMR to ensure safe and effective care for our young patients.UF, VC, and MP performed the literature review and wrote the first draft of the manuscript. PG and SE critically revised the text and made substantial scientific contributions. All authors approved the final version of the manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.


In this study, mechanical and electrical properties of concrete containing steelmaking slag as a binder were evaluated. As the incorporation of steelmaking slag increased, the setting times were delayed, but the compressive strengths were similar within the replacement ratio of 15%. It was found that the addition of steelmaking slag with Fe2O3, the main ingredient of magnetite (Fe3O4), improved the electrical resistivity, piezoresistivity, and sensitivity of the concrete. Drying of the concretes resulted in an increase in electrical resistance and fractional change in resistivity (FCR). Expansion of steelmaking slag, due to contacting of free CaO and moisture under repeated loads, resulted in cracks in the concrete and affected the gauge factor (GF). This study demonstrates the possibility that the addition of steelmaking slag as a binder may provide an economical and environmentally-friendly solution to concrete strain monitoring.Strain sensors can indicate the conditions of concrete structures, but these sensors are only capable of measuring local behaviors of materials. To solve this problem, researchers have introduced conductive materials that can monitor the overall behavior of concrete structures. Steelmaking slag, which contains large amounts of iron oxide (Fe As concrete technology improves, concrete structures are lasting longer and are subject to material deterioration and changing environments, including climate ,2,3. EnvConcrete and cement composites become sensible by incorporating special functional fibers and fillers. It is well-known that incorporation or replacement ratio of conductive materials, distribution states of fillers, and types of additives strongly influence the conductivity of cement composites and concretes. Choi et al.  found thMeanwhile, recently, high-strength reinforcing bars have been developed and manufactured to improve structural performance of concrete structures. As the production of high-strength reinforcing bars increases, so does the production of steelmaking slag, a steel byproduct for which it is difficult to secure a site for aging and landfilling . However2) generated in concrete and construction fields. The production of one ton of ordinary Portland cement (OPC) generates 1 ton of CO2, and it is estimated that 7% of the worldwide CO2 generation can be attributed to the cement industry [The substitution of cement to steelmaking slag may also decrease the amount of carbon dioxide  and electrical  properties of concrete. Because moisture in concrete is reported to have a significant effect on the electrical properties of concrete, the electrical properties of the concrete with steelmaking slag was also compared before and after drying.The mix design of the concrete specimens used in this study are shown in 2O3). Steelmaking slag was first crushed with a jaw crusher, and then a ball mill was used to make steelmaking slag aggregate into powder. It was grounded by a ball mill for 3 h and the blaine of steelmaking slag reached approximately 5000 cm2/g. Particle size distribution was analyzed through CILAS 990, and steelmaking slag had a mean diameter of 27.15 μm. Both cementitious materials and aggregates were produced in Republic of Korea. River sand was used as fine aggregate, and the coarse aggregate had a maximum dimension of 19 mm. To determinate the size of aggregates, sieve analysis was performed according to ASTM C136 [3 with dark brown color was incorporated into all mixes to improve workability.STM C136 . Figure STM C136 . These pSetting, compressive strength, and splitting tensile strength tests were carried out to evaluate the strength characteristics of all the mixes. According to the method specified in ASTM International, setting test specimen was ∅150 mm × 150 mm in size, and the compressive and splitting tensile strength test specimens were fabricated into cylinders of ∅100 mm × 200 mm ,22,23,24In general, electrical resistance can be measured with two- and four-probe methods. Although the two-probe method has a simpler circuit than the four-probe method, some studies have reported that the four-probe method is easier to control contact resistance than the two-probe method ,25,26. TTo evaluate the change of electrical resistance with age, the electrical resistance was measured at the designated age using an LCR meter . In addition, to assess the self-sensing capacity of concrete incorporated with steelmaking slag, a cyclic compressive load was applied to a 150 mm cubic test specimen using a universal testing machine  after 28 days from the casting. The steel plates were placed on both the upper and lower sides of the test specimen so that equal compressive forces were distributed to the test specimen under loading. In addition, to eliminate the effect of steel plates when measuring electrical resistance, an approximately 2-mm-thick piece of rubber that acts as an insulator was placed between the test specimen and the steel plates ,31. ConcPR is the penetration resistance stress in MPa, t is the elapsed time after mixing, and a and b are the regression constants.To determine the setting times of all mixes, the penetration resistance stress was measured over time. Afterwards, the initial and final setting time were derived through the regression analysis using Equation (1), and the time points at which the penetration resistance stress satisfied 3.5 and 28.0 MPa were defined as initial and final setting, respectively.The NN took 4.54 h (272 min) to reach the initial setting and 8.79 h (528 min) to reach the final setting. However, for mixes that contained any amount of steelmaking slag, initial and final setting of all the mixes occurred after 5 and 9 h respectively. As the replacement ratio of steelmaking slag increased, the hydration process tended to be more delayed, which was attributed to the decrease in cement usage due to replacement of steelmaking slag. In addition, steelmaking slag has a lower hydraulicity compared to cement, which is another reason for delay of setting times . For theThe splitting tensile strength of concrete containing steelmaking slag also followed similar trends as those of compressive strength, which is shown in ρ is the electrical resistivity, R is the electrical resistance measured by LCR meter, A is the contact area of the concrete with the electrode, and l is the distance between the electrodes.Electrical resistivity is an indicator that can express the electrical properties of concrete. In this study, electrical resistance was measured at the designated age, and the electrical resistivity was derived by substituting it into Equation (2).3O4), with the electrical conductivity of 100–1000 Ω−1 cm−1, and this is within the range of semi-conductors [Steelmaking slag is a well-known conductive material that has a large amount of iron oxide, which is the main ingredient of magnetite . Equation (3) is an expression of FCR.In general, when a compressive load is applied to a test specimen, the electrical resistance in the test specimen decreases, resulting in a negative FCR. However, in this study, to smoothly compare the behavior of compressive load and FCR, the FCR was multiplied by a negative number (−1) so that a positive value appeared. In the normal series, it can be seen that NN increases the FCR in a straight line according to the change in load in Stage 1 (load range: 10–20 kN). In contrast, for SS10, SS15, SS20, and SS15G, the FCR fluctuated flexibly with changes in load. This result reflects that the steelmaking slag used in this study contains a large amount (approximately 40%) of iron oxide that was distributed evenly within the concrete matrix to form conductive paths. It is noteworthy that gypsum had a positive effect on FCR as well as electrical resistivity when repeated loads were applied, so that the best FCR behavior and FCR values were shown even at low load ranges. In Stage 2 (load range: 10–50 kN), the FCR fluctuated similarly with the change of the load for all mixes. This is because the distance between the steelmaking slag that was distributed inside the concrete matrix decreased as the maximum load increased compared to Stage 1, thereby increasing the formation of conductive paths ,36. The After casting concrete, the internal moisture decreases with time, and finally it becomes dry condition. Decreasing moisture inside concrete increases electrical resistivity and degrades electrical properties. Therefore, in this study, the FCR of concrete was evaluated by drying the test specimens at a certain temperature for a specific period of time to exclude the effect of moisture in the concrete on the electrical properties . In the ε is the strain of the concrete surface.The electrical sensitivity of concrete can be evaluated with a gauge factor (GF). In this study, the concrete surface strain and electrical resistance changes of the concrete were measured by applying the repeated compressive loads, and the GF was calculated by substituting them into Equation (4).In general, the conductivity of concrete is affected by the moisture in the concrete. Demircilioglu et al.  and SongSteelmaking slag delayed hydration process, and, when steelmaking slag was incorporated, the strength decreased. However, it was confirmed that the reduction of the strength of the concrete containing steelmaking slag could be improved through the incorporation of gypsum.The electrical conductivity of steelmaking slag is included in the range of semi-conductors, and the electrical resistivity decreased as the replacement ratio of steelmaking slag increased. In addition, the incorporation of gypsum improved the conductivity of the concrete. On the other hand, the electrical resistivity is dependent on the moisture in the concrete, and, when the concrete specimen was dried, the electrical resistivity increased about two times or more.The iron oxide in the steelmaking slag formed a conductive path in the concrete, and the reduction of the potential barrier due to the increase in the cyclic compressive load increased the FCR. The dry series showed higher FCR values than the normal series, and, when the specimen was dried, the maximum FCRs of SS15, SS20, and SS15G increased by 40.10%, 129.68%, and 23.70%, respectively. Through this, it could be seen that the electrical piezoresistivity of concrete was affected by moisture.The GF improved as the replacement ratio of the steelmaking slag increased. In general, when the moisture in concrete decreases, the GF decreases; however, the mixes incorporating only steelmaking slag showed the opposite trend. This was because moisture in concrete came into contact with free CaO and caused cracks, which affected the conductive path in concrete. When the specimens were dried, the GF of SS10, SS15, and SS20 increased by 37, 27, and 135, respectively.In this study, the effect of the replacement ratio of steelmaking slag on the electrical properties of concrete was evaluated and the moisture in concrete was also considered. The conclusions drawn from this study are as follows:


Levels of pleural fluid adenosine deaminase (ADA), a useful marker for the diagnosis of tuberculous pleurisy, are elevated in some reports of immunoglobulin G4 (IgG4)-related pleural effusion. We describe a patient with IgG4-related pleural effusion who exhibited a high concentration of ADA. Furthermore, we reviewed the literature to compare patients with IgG4-related pleural effusion and tuberculous pleurisy.A 75-year-old male patient had dyspnea for 1 month with a left pleural effusion that was exudative, lymphocyte dominant. The pleural fluid test results revealed a total protein (TP) concentration of 6.60 g/dl, a lactate dehydrogenase (LDH) level of 383 IU/dl, and an ADA concentration of 54.5 U/L. An interferon gamma release assay showed a negative result.Histological analysis of the thoracoscopic pleural biopsy revealed lymphoplasmacytic infiltration, with 80 IgG4-positive plasma cells/high-power field, and an IgG4/IgG ratio of approximately 40% to 50%. Other diseases were ruled out based on symptoms, negative autoimmune antigen results, and histopathologic findings. Thus, he was diagnosed with IgG4-related pleural effusion.He received 15 mg of prednisolone as therapy.His pleural effusion and symptoms improved gradually within several months, and prednisolone was tapered to 6 mg daily.P < .001) and lower LDH (P < .001) and ADA levels (P = .002) than those with tuberculous pleurisy. Moreover, the pleural fluid ADA/TP ratio was a good predictor for differentiating IgG4-related pleural effusion and tuberculous pleurisy .It is important to distinguish between IgG4-related pleural effusion and tuberculous pleurisy. Therefore, we compared 22 patients with IgG4-related pleural effusion from PubMed and the Japan Medical Abstracts Society to 40 patients with tuberculous pleurisy at Fukujuji Hospital from January 2017 to May 2019. According to thoracentesis findings, 14 of 18 patients with IgG4-related pleural effusion had high ADA more than 40 U/L. The pleural effusion of patients with IgG4-related pleural effusion showed higher TP levels ( Histopathologic findings of IgG4-RD involve the appearance of dense lymphoplasmacytic infiltrates with abundant IgG4-positive plasma cells and characteristic fibrosis.,2 The rates of IgG4-related pleural effusion are reportedly 1.6% among patients with IgG4-RD and 4.6% among IgG4-RD patients with intrathoracic lesions. In general, IgG4-related pleural effusion is exudative with a predominance of lymphocytes and/or plasma cells, though these clinical features are not fully understood. Some reports of IgG4-related pleural effusion have indicated an adenosine deaminase (ADA) level higher than 40 U/ml in pleural effusion.–7 The level of ADA in pleural fluid is generally used as a marker for the diagnosis of tuberculous pleurisy–10 and it is therefore difficult to differentiate between IgG4-related pleural effusion and tuberculous pleurisy.–7Immunoglobulin G4 (IgG4)-related pleural effusion is a rare phenotype of IgG4-related disease (IgG4-RD),Here, we describe a patient with IgG4-related pleural effusion who had a high concentration of ADA. Furthermore, we compare IgG4-related pleural effusion with tuberculous pleurisy based on a literature review.2This case involves a 75-year-old male patient who had dyspnea for 1 month prior to admission. He had a medical history of chronic obstructive pulmonary disease, diabetes mellitus, hepatitis B, and gastric polyps. He had a smoking history (45 pack-years) and was allergic to mackerel. He was diagnosed with autoimmune pancreatitis by his previous doctor and began 5.0 mg of oral prednisolone daily when he was 67 years old; his prednisolone dosage was decreased to 2.5 mg daily one year ago. He visited our hospital 8 months prior due to cough and sputum. He was diagnosed with asthma and chronic obstructive pulmonary disease overlap because of obstructive ventilatory disturbance and reversibility by short-acting β2 agonists by spirometry. His symptoms had been improved by treatment with inhaled vilanterol trifenatate/fluticasone furoate and oral montelukast sodium. Nonetheless, dyspnea gradually developed, as did a painless left pleural effusion on chest radiography, and he was thus admitted to our hospital.18F-fluorodeoxyglucose positron emission tomography imaging (FDG-PET/CT) showed accumulation of fluorodeoxyglucose in the left pleura and mediastinal lymph nodes as well as peripheral consolidation in the right upper lobe and prostate gland. No abnormal pancreatic findings were detected by CT scan or FDG-PET/CT. The pleural effusion obtained by thoracentesis showed a total cell count of 4907/μl (lymphocytes 83.5%), total protein (TP) of 6.60 g/dl, lactate dehydrogenase (LDH) of 383 IU/dl, and ADA of 54.5 U/L. Pleural fluid bacterial culture, tuberculosis examination , and cytology were negative.His vital signs were normal, and physical examinations revealed no abnormalities. Laboratory findings were as follows: white blood cell count 11,220/μl, with 76.5% polymorphic nuclear leukocytes and 5.5% eosinophils; C-reactive protein 0.29 mg/dl; hemoglobin A1c 6.5%; serum IgG level 3556 mg/dl, including 1310 mg/dl of IgG4; and serum immunoglobulin E level 3968 U/ml .Because of the high concentrations of ADA in the pleural effusion, we could not distinguish between IgG4-related pleural effusion and tuberculous pleurisy. Therefore, we performed a thoracoscopic pleural biopsy, and histological analysis revealed the presence of dense collagenous fibrosis with lymphoplasmacytic infiltration with no malignancy or granuloma Fig. . Immunoh3We report a case of IgG4-related pleural effusion with a high concentration of ADA in the pleural effusion. In this case, it was difficult to distinguish IgG4-related pleural effusion from tuberculous pleurisy without performing thoracoscopic pleural biopsy. The pleural fluid IgG4 level was elevated, similar to the serum IgG4 level. His mediastinal lymph nodes, lung, and prostate gland might be also affected by IgG4-RD due to observed accumulation by FDG-PET/CT. However, histopathological examinations of those organs were not performed. Chest radiography showed that the interstitial changes and mediastinal lymph nodes in his lung improved after starting steroid therapy.,13 The level of pleural fluid ADA is a useful marker for the diagnosis of tuberculous pleurisy.–10 Conversely, pleural fluid smear microscopy and cultures show low rates of positivity for the diagnosis of tuberculous pleurisy . Even polymerase chain reaction tests (sensitivity 51.4%) and interferon gamma release assay (sensitivity 72%) for pleural effusion have suboptimal diagnostic accuracies with regard to tuberculous pleurisy.,16 The most widely accepted cut-off value of pleural fluid ADA for diagnosing tuberculous pleurisy is 40 U/L, with a sensitivity and specificity of 92% and 90%, respectively. Therefore, an elevated pleural fluid ADA level is useful for diagnosing tuberculous pleurisy.–10,17 Diseases with high pleural fluid ADA levels other than tuberculosis include empyema, malignancies, infectious diseases, and connective tissue diseases such as rheumatoid arthritis.,9 Castro et al reported that 1.71% of nontuberculous lymphocytic pleural effusions show a high ADA level, exceeding 40 U/L. The mechanism of ADA production suggests that the interaction of T cells with B cells may induce the activation of cell-mediated immunity, but it has not been fully elucidated.,9 ADA is categorized as ADA-1 and ADA-2, and ADA-2, which is induced by the stimulation of monocytes/macrophages, is mainly activated in tuberculous pleural effusion.,19 Low ADA-2 activities are observed among other diseases, such as neoplastic exudate, empyema, and parapneumonic exudate.,19 However, only total ADA can be routinely measured at our clinical practice. Regarding IgG4-related pleural effusion, a previous review of 8 cases showed slightly elevated pleural fluid ADA levels, with a median of 32.2 U/L (range 26.6–50.1), which was significantly higher than that in non-IgG4-related cases without tuberculous pleurisy (P = .05). Considering that ADA levels are elevated in both IgG4-related pleural effusion and tuberculous pleurisy, it is very important to distinguish between them because of the different treatments. Indeed, the first-line treatment for IgG4-RD is glucocorticoids, but glucocorticoids influence the development of tuberculous infection. Therefore, the comparison between IgG4-related pleural effusion and tuberculous pleurisy is very important.The most instructive point in our report is the high concentration of pleural fluid ADA, even though it was not due to tuberculous pleurisy. ADA is an enzyme participating in purine catabolism in the pathway from adenosine to inosine and is produced by lymphocytes. All data were analyzed and processed using EZR, version 1.35.In addition to the current case, we collected past case reports of IgG4-related pleural effusion from PubMed and the Japan Medical Abstracts Society database using the keywords “IgG4 pleuritis,” “IgG4 pleural effusion,” and “Mikulicz's disease pleural effusion”. The search was limited to in English and Japanese languages only. We searched using those keywords in Japanese in the Japan Medical Abstracts Society database and excluded reports without an English abstract. Furthermore, we retrospectively studied patients who were diagnosed with tuberculous pleurisy due to tubercle bacilli cultured from pleural effusion at the Respiratory Disease Center of Fukujuji Hospital from January 2017 to March 2019. We excluded the cases with no laboratory data. Among cases with suspected IgG4-related pleural effusion, we also excluded those that did not meet the diagnostic criteria for IgG4-related disease.–7,22–39 and 40 patients with tuberculous pleurisy. Table  Regarding thoracentesis findings, lymphocytes were dominant in both diseases, with no significant difference (P = .629). The median pleural fluid ADA level in IgG4-related pleural effusion was elevated to 55.7 U/L (interquartile range (IQR) 42.3–71.6), which was lower than that in tuberculous pleurisy (median (IQR): 83.9 U/L (60.4–109.4), P = .002). Of 18 patients with IgG4-related pleural effusion, 14 (77.8%) showed a high pleural fluid ADA of more than 40 U/L. Patients with IgG4-related pleural effusion showed higher pleural fluid TP  and pleural fluid glucose , and lower pleural fluid LDH  than those with tuberculous pleurisy. The pleural fluid ADA/TP ratio is a good predictor for differentiating between IgG4-related pleural effusion and tuberculous pleurisy, with an area under the receiver operating characteristic curve of 0.909 : 0.824–0.994) , which was slightly higher than the serum IgG4 level  1.12 (0.76–1.27)). A high concentration of pleural fluid IgG4 might be useful for diagnosing IgG4-related pleural effusion; however, we were unable to compare this for patients with tuberculous pleurisy because of a lack of data. In 9 of 22 patients with IgG4-related pleural effusion, organs other than pleuritis were not affected.We collected 22 patients with IgG4-related pleural effusion, including our patient,This study had several limitations. The review was conducted retrospectively in a single-center hospital, and some medical data were not recorded. In addition, publication bias exists because the data for many of the patients with IgG4-related pleural effusion were obtained from published reports.4We report a patient with IgG4-related pleural effusion, which is difficult to distinguish from tuberculous pleurisy due to a high pleural fluid ADA level. The pleural fluid ADA/TP ratio is useful for distinguishing IgG4-related pleural effusion from tuberculous pleurisy.Conceptualization: Masafumi Shimoda, Yoshiaki Tanaka.Data curation: Masafumi Shimoda, Yoshiaki Tanaka, Kozo Morimoto, Masao Okumura, Kiyomi Shimoda, Tamiko Takemura, Teruaki Oka, Takashi Yoshiyama, Kozo Yoshimori.Formal analysis: Masafumi Shimoda.Investigation: Masafumi Shimoda, Kiyomi Shimoda, Tamiko Takemura, Teruaki Oka.Methodology: Masafumi Shimoda, Yoshiaki Tanaka.Project administration: Masafumi Shimoda, Kozo Yoshimori, Ken Ohta.Resources: Masafumi Shimoda.Software: Masafumi Shimoda.Supervision: Yoshiaki Tanaka, Kozo Morimoto, Takashi Yoshiyama, Kozo Yoshimori, Ken Ohta.Validation: Masafumi Shimoda, Yoshiaki Tanaka.Visualization: Masafumi Shimoda.Writing – original draft: Masafumi Shimoda.Writing – review & editing: Masafumi Shimoda, Yoshiaki Tanaka.


Cardiomyocytes isolated from adult or AKT-knockout mice were treated with HG (33 mmol/L) and PK2 or AKT1/2 kinase inhibitor (AKT inhibitor). Heart contraction properties based on cell shortening were evaluated; these properties included the resting cell length, peak shortening (PS), maximum speed of shortening/relengthening (±dL/dt), time to 90% relengthening (TR90), and time to peak shortening (TPS). Mice with streptozotocin-induced diabetes were treated with Met to evaluate cardiac function, myocardial structure, and the PK2/PKR and AKT/GSK3β pathways. Moreover, H9c2 cardiomyocytes were exposed to HG in the absence or presence of Met with or without the PK2 antagonist PKRA7 or the AKT inhibitor, and apoptotic proteins such as Bax and Bcl-2 and the PK2/PKR and AKT/GSK3β pathways were evaluated using western blot analysis. The prolongation of TR90 and decreases in PS and ±dL/dt caused by HG were ameliorated by PK2 in cardiomyocytes, but the effects of PK2 were ameliorated or negated by the AKT inhibitor and in AKT-knockout mice. Diabetic mice showed metabolic abnormalities, aberrant myocardial enzyme levels, declines in myocardial systolic and diastolic function associated with myocardial fibrosis, and pronounced apoptosis, but these effects were greatly rescued by Met treatment. Moreover, PK2, PKR1, and PKR2 expression and p-AKT/AKT and p-GSK3β/GSK3β ratios were decreased in diabetic mice, and these decreases were attenuated by Met. Likewise, H9c2 cells exposed to HG showed reduced PK2/PKR expression and decreased p-AKT/AKT and p-GSK3β/GSK3β ratios, and these effects were nullified by Met. In addition, the effects of Met on cardiomyocytes exposed to HG were abolished after intervention with PKRA7 or the AKT inhibitor. These results suggest that Met can activate the PK2/PKR-mediated AKT/GSK3β pathway, thus improving cardiac function and alleviating apoptosis in DM mice.Diabetic cardiomyopathy (DCM) is a complication of diabetes that can cause damage to myocardial structure and function. Metformin (Met) is a widely used type 2 diabetes treatment drug that exerts cardioprotective effects through multiple pathways. Prokineticin 2 (PK2) is a small-molecule secreted protein that plays pivotal parts in cardiomyocyte survival and angiogenesis. However, the role of Met in regulating the PK2 signaling pathway in DCM remains unclear. This experiment explored the effects of Met on high glucose (HG)-induced injury through the PK2/PKR pathway  Currently, the diabetic population is becoming younger, and the International Diabetes Federation has reported that the total number of people with diabetes is expected to reach 642 million by 2040 . Diabeteiabetics . In the iabetics . HoweverProkineticin 2 (PK2) is an 8-kDa small-molecule secreted protein . PK2 belMetformin (Met) is a well-known therapeutic drug for diabetes. Met reduces blood glucose mainly by activating AMP-activated protein kinase (AMPK) and non-AMPK pathways. Met is thought to exert its primary antidiabetic action through the suppression of hepatic glucose production . Met is Male C57BL/6J mice  were purchased from Jinan Pengyue Experimental Animal Breeding Co., Ltd. (China). AKT-knockout mice were provided by the University of Wyoming . The animal protocols were in accordance with the Guide for the Care and Use of Laboratory Animals, and the use of the animals was approved by the Institutional Animal Care and Use Committee at Hubei University of Science and Technology.2+ was added to a concentration of 1.25 mmol/L. The cardiomyocytes were used for shortening experiments. The mechanical properties of myocytes were evaluated with an IonOptix SoftEdge system. The resting cell length, time to peak shortening (TPS), peak shortening (PS), time to 90% relengthening (TR90), and maximum speed of shortening/relengthening (±dL/dt) were measured to evaluate cell shortening and relengthening after stimulation at 0.5 Hz , a DM group (n = 25), and a DM-Met group (n = 25). The mice in the DM group and the DM-Met group were injected intraperitoneally with 50 mg/kg/day streptozotocin  for five consecutive days. The control mice were administered with citrate buffer. Mice with blood glucose levels higher than 16.7 mmol/L were considered diabetic. The mice in the DM-Met group were given 250 mg/kg/day Met  in drinking water for 16 weeks.Mice were randomized into three groups: a control group (2 and 95% air). H9c2 cells were incubated with normal glucose  or HG (33 mmol/L) for 72 h with or without Met , a PK2 antagonist , and an AKT1/2 kinase inhibitor .The H9c2 cell line was purchased from the China Center for Type Culture Collection , and the cells were cultured and maintained in Dulbecco’s modified Eagle’s medium  supplemented with fetal bovine serum , penicillin , and streptomycin at 37°C in a humidified atmosphere , left ventricular ejection fraction (LVEF), left ventricular fractional shortening (LVFS), left ventricular posterior wall thickness in diastole (LVPWD), and left ventricular internal dimension in end-diastole (LVIDD), were measured and calculated.Cardiac tissue was fixed in 4% paraformaldehyde for 24 h and then embedded and sectioned. The sections were stained with hematoxylin and eosin (HE) and Masson’s trichrome. Myocardial microstructure was observed under a light microscope. Additional cardiac tissue was fixed in electron microscopy fixative and embedded in an acetone-812 embedding agent. The tissues were cut into 60-nm-thick sections and stained with uranyl acetate and lead citrate. Myocardial ultramicrostructure was observed by electron microscopy.Blood was collected from each group of animals, stored at 4°C overnight, and centrifuged at 3000 r/min for 15 min at 4°C in a low-temperature ultracentrifuge. The levels of lactic dehydrogenase (LDH), aspartate aminotransferase (AST), creatine kinase (CK), total cholesterol (TC), and triglyceride (TG) in the serum were tested according to procedures from the Nanjing Jiancheng Institute of Biological Engineering (China).Total RNA was extracted from heart tissues with TRIzol reagent. Reverse transcription was performed to synthesize cDNA. The samples were incubated at 65°C for 5 min and then cooled on ice. Reaction buffer (5×), mixed dNTPs, RiboLock RNase inhibitor, and RevertAid M-MuLV reverse transcriptase were sequentially added. The samples were incubated at 42°C for 60 min in a PCR instrument, and the reverse transcriptase was inactivated at 70°C for 5 min. The PCR amplification reaction conditions were as follows: 95°C for 10 min, 95°C for 15 s, and annealing at 60°C for 60 s for 40 cycles. Melting curve analysis was performed from 60°C to 95°C in 0.3°C increments over 15 s. The results were analyzed by the ΔΔCT method. After dewaxing and hydration of the conventionally prepared paraffin slices, the samples were incubated with primary antibodies (working concentration: 1:1000) at 4°C for 12 h and then incubated with secondary antibodies for 1 h. A solution of diaminobenzidine was added dropwise, and the slices were observed under a microscope. The procedure was carried out according to the kit instructions.Apoptosis was tested with a terminal deoxynucleotidyl transferase-mediated dUTP-biotin nick end labeling (TUNEL) assay in paraffin-embedded heart sections. Ten fields were analyzed for each slice, and the number of positive cells among cardiomyocytes was determined for each field. The apoptosis rates were calculated as the percentages of positive cells .Fifty milligrams of myocardial tissue was weighed, and RIPA lysis buffer was added. A BCA Protein Assay Kit  was used to test the protein concentration. Protein (50 mg) was added to each lane of a 12% SDS-polyacrylamide gel, and the proteins were separated and transferred to a polyvinylidene fluoride (PVDF) membrane. The membrane was blocked and incubated overnight at 4°C with AKT, p-AKT, GSK3β, p-GSK3β, Bax, Bcl-2 , PK2 , PKR1, and PKR2  antibodies. After incubation with secondary antibodies for an hour, the analysis was completed using an Enhanced Chemiluminescence Kit .T-tests or one-way ANOVA was performed for all statistical analyses. T-tests were applied to analyze differences between two groups, and one-way ANOVA (Student–Newman–Keuls) was used to analyze differences among three or more groups. A P value less than 0.05 was considered to indicate statistical significance.The data are presented as the mean ± standard error of the mean (SEM). 90 significantly but did not affect the resting cell length or TPS. PK2 significantly alleviated the HG-induced abnormalities in PS, ±dL/dt, and TR90 but had no effect on TPS or resting cell length. The effects were ameliorated or negated in AKT-knockout mouse cardiomyocytes and by AKT inhibitor treatment. These data strongly indicate that PK2 plays a pivotal role in the diabetic heart and that the important roles of AKT in PK2 provide benefits against glucose toxicity.As shown in Body weight (BW), heart weight (HW), and blood glucose levels reflect the general health state of mice. The results showed that BW and HW were significantly decreased and that the heart-to-body weight ratio (HW/BW) was significantly increased in the DM group compared with the control group; these changes were overtly reversed by Met treatment . In addiEchocardiography is a technique for examining the anatomy and function of the heart. Echocardiographic evaluation revealed that LVPWD and LVIDD were slightly increased in DM mice, but these increases were mitigated by Met. Moreover, HR was significantly reduced in DM mice, and the reduction was partly eliminated by Met. Moreover, DM mice showed remarkable reductions in both LVEF and LVFS that were notably nullified by Met .Myocardial zymograms are recognized as effective indicators of cardiac function. The levels of LDH, CK, and AST in serum were significantly increased in the DM group compared to the control group, the effects of which were reversed by Met administration . MoreoveHematoxylin and eosin staining showed that the myocardial cells in the control group were clearly visible and arranged neatly, while those in the DM group showed disordered myocardial fiber arrangement and vacuolization. Interestingly, the myocardial fibers were denser in the Met treatment group than in the DM group, and less vacuolization was observed .Masson’s trichrome staining showed that there was less blue collagen in the myocardial interstitium in the control group than in the other groups. In contrast, increased interstitial fibrosis was evident in the DM mice hearts, and the fibrotic changes were significantly attenuated after Met administration .Electron microscopy revealed that in the control group, the mitochondria were intact, the myofilaments were neat and complete, and the Z-line and M-line were clear. However, in the DM group, the myocardial cells were arranged in a disorderly manner, the mitochondria were swollen, and myofilament fracture was present. Met ameliorated these abnormalities, causing the myofilament arrangement to be more regular and the mitochondrial structure to be more complete and reducing myofilament fracture .TUNEL staining was used to detect apoptotic cardiomyocytes. The data showed that there were many more apoptotic cardiomyocytes (stained in brown) in the DM group than in the control group, but Met treatment significantly decreased DM-induced myocardial cell apoptosis .Apoptosis-related proteins play important roles in apoptosis progression. We thus carried out a more in-depth experiment to investigate whether apoptosis-related proteins affected the amelioration of DM-induced cardiomyocyte apoptosis by Met. As shown in Previous studies have suggested that PK2 plays essential roles in the survival, proliferation, and apoptosis of cardiomyocytes. To further elucidate the role of PK2 in Met-mediated cardioprotection, we measured the effects of Met on PK2/PKR signaling pathway members. The results of immunohistochemical staining showed that the expression of PK2, PKR1, and PKR2 (brown labeling) was lower in the DM group than in the control group, the effects of which were ablated by Met treatment . ConstanPreviously obtained evidence has revealed that the cardioprotective actions of PK2/PKR may involve the phosphorylation of AKT, and impaired AKT activity in response to insulin is a common feature of DM . We therin vitro, the PK2/PKR signaling pathway was examined using western blot analysis. The data showed that PK2, PKR1, and PKR2 expression levels were overtly decreased in H9c2 cardiomyocytes exposed to HG, but the changes were significantly abrogated by Met treatment (To further validate the role of the PK2/PKR pathway in Met-induced cardiomyocyte mechanical responses against HG reatment .To determine whether Met activates the PK2-mediated AKT/GSK3β signaling pathway in HG-treated cardiomyocytes, AKT and GSK3β signaling was examined using western blot analysis. As demonstrated in To clarify whether PK2 and PK2-mediated AKT play key roles in the Met-induced beneficial response to HG challenge, cardiomyocytes were incubated with NG or HG medium in the absence or presence of Met and PKRA7 or an AKT inhibitor. As shown in The salient findings from our current study suggest that the PK2/PKR pathway plays a crucial role in the pathogenesis of DCM and that Met treatment prevents diabetes-induced glucose and lipid metabolism dysfunction, cardiomyocyte apoptosis, fibrosis, and cardiac insufficiency by stimulating PK2/PKR and the downstream AKT/GSK3β pathway. Glucose toxicity is considered to be the key factor in cardiovascular complications caused by diabetes, but the clinical treatment of DCM is still challenging. Our data reveal a likely role for the PK2/PKR pathway in the anti-DCM effects of Met.It is well known that myocardial fibrosis and apoptosis contribute to the development of DCM . Several90 in cardiomyocytes, supporting that PK2 may be the key factor in DCM. Prokineticins exert multiple biological effects by activating PKR1 and PKR2 and mostly differ in their N-terminal sequences. Previous studies have revealed that PK2 and PKR1 levels are reduced in the late stage of heart failure, but PKR1 overexpression can protect cardiomyocytes from hypoxia injury-elicited apoptosis (in vitro, we made further efforts to investigate the protective effect of Met on HG-induced cardiac damage mediated via regulation of the PK2/PKR pathway in vitro and in vivo. As expected, our current results suggested that PK2, PKR1, and PKR2 expression was remarkably dampened both in diabetic mouse hearts and H9c2 cardiomyocytes exposure to HG, which further confirmed that a decrease in PK2 may be the main contributor to myocardial apoptosis in DCM. Interestingly, after administration of Met, PK2, PKR1, and PKR2 expression was significantly increased in vivo and in vitro. In addition, PKRA7 partly or considerably counteracted the beneficial effects of Met against glucose toxicity. Our observations favored a role for activation PK2/PKR pathway in the Met-offered beneficial mechanical effects against HG-induced cardiac damage.Prokineticin 2 expression has been observed in a variety of tissues, such as the brain, heart, and testes. PK2 affects various biological processes, including neuronal survival, olfactory bulb morphogenesis, testis development, and circadian rhythms . In recepoptosis . Moreovepoptosis . Upregulpoptosis . Similarpoptosis . In addipoptosis . RecentlCumulative evidence suggests that PK2/PKR participates in myocardial survival, angiogenesis, and the hematopoietic system through the AKT and STAT3 signaling pathways . AKT appin vivo diabetes animal models and in vitro HG-exposed cardiomyocytes. Any conclusions about the exact role of the Met activated PK2-AKT signaling cascade in DCM must be taken with caution. As proof of concept evidence is still lacking from genetically engineered mouse models of PK2 and AKT, it is quite challenging to better understand the role of PK2 signaling in biological process.Our current studies have elucidated the important role of PK2 signaling cascade in DCM and Met ameliorates HG-induced cardiac damage through the PK2-mediated AKT/GSK3β pathway using In summary, our data suggest that PK2 may participate in pathophysiological changes in DCM and that Met protects against diabetes-induced cardiac and remodeling, apoptosis, and dysfunction via activation of the PK2/PKR signaling, thereby regulating the AKT/GSK3β pathway. These findings suggest new strategies for the prevention and treatment of DCM, which are worthy of further clinical study.The raw data supporting the conclusions of this article will be made available by the authors, without undue reservation, to any qualified researcher.The animal study was reviewed and approved by the Institutional Animal Care and Use Committee at Hubei University of Science and Technology.ZY, MW, YZ, FC, and BJ performed the experiments. WZ and WY contributed to analysis and interpretation of the data, and responsible for critically revising the manuscript. All authors read and approved the final manuscript.The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest.