We aimed to compare the demographic, clinical and laboratory characteristics between IgG4-related kidney disease (IgG4-RKD+) and extrarenal IgG4-related disease (IgG4-RKD−) in a large Chinese cohort, as well as describing the radiological and pathological features of IgG4-RKD+. We retrospectively analyzed the medical records of 470 IgG4-related disease (IgG4-RD) patients at Peking University People’s Hospital from January 2004 to January 2020. The demographic, clinical, laboratory, radiological and pathological characteristics between IgG4-RKD+ and IgG4-RKD− were compared. Twenty IgG4-RD patients who had definite etiology of renal impairment including diabetes, hypertension and etc. were excluded. Among the remained 450 IgG4-RD patients, 53 were diagnosed with IgG4-RKD+ . IgG4-RKD+ patients had older age at onset and at diagnosis. Male to female ratio of IgG4-RKD+ patients is significantly higher. In the IgG4-RKD+ group, the most commonly involved organs were salivary gland, lymph nodes and pancreas. It was found that renal function was impaired in approximately 40% of IgG4-RKD+ patients. The most common imaging finding is multiple, often bilateral, hypodense lesions. Male sex, more than three organs involved, and low serum C3 level were risk factors for IgG4-RKD+ in IgG4-RD patients. These findings indicate potential differences in pathogenesis of these two phenotypes. Subsequent studies have revealed that IgG4-RD can affect any organ system. IgG4-related kidney disease (IgG4-RKD+) refers to the renal lesions in association with IgG4-RD. Previous studies have reported the kidney involvement in approximately 12–23% of total IgG4-RD patients8. IgG4-RKD+ could be manifested by a variety of clinical and histological characteristics, such as tubulointerstitial nephritis (TIN), membranous glomerulonephropathy (MGN) and other infrequent glomerular lesions, pyelitis, hydronephrosis and acute renal failure10.In 2001, IgG4-RD was first described in pancreas, which was called type 1 autoimmune pancreatitis (AIP)To minimize the impact of irreversible renal damage resulting from the disease itself or unnecessary surgical intervention, early recognition and treatment are of pivotal importance. In this study, demographic, clinical, and laboratory disparities in the 53 IgG4-RKD+ and 397 IgG4RKD− patients were investigated. To our best knowledge, this is the largest study to compare the two phenotypes of patients with or without IgG4-RKD+. Determining the characteristics of these two phenotypes may help identify risk factors and their potential differences in pathogenesis.12. Twenty IgG4-RD patients who had definite etiology of renal impairment including diabetes, hypertension and etc. were excluded. Therefore, four hundred and fifty IgG4-RD patients were enrolled into the cohort , 35 (7.8%) and 199 (44.2%) cases diagnosed with definite, probable and possible IgG4-RD, respectively , allergic disease was diagnosed by experienced specialists. This study was approved by the Medical Ethics Committee of Peking University People’s Hospital . According to national regulations and in accordance with the Declaration of Helsinki, data protection authority and medical research ethical committee gave their approval.We recorded laboratory tests, including serum IgG4 level, serum IgE level, C-reactive protein (CRP), erythrocyte sedimentation rate (ESR), eosinophilia, serum C3, serum C4, hemoglobulin (Hb), and renal function , serum β2-microglobulin (β2-MG), urine N-acetyl-β-D-glucosidase (NAG), and retinol-binding protein (RBP)).All patients underwent radiology examinations consisting of Computed Tomography (CT), or Magnetic resonance imaging (MRI), and some patients also received 18F-fluorodeoxyglucose PET-CT.We fixed all tissue biopsy samples in formalin and embedded in paraffin, then stained them with hematoxylin and eosin (H&E) and immunocytochemistry (IHC). IHC was performed using the avidin–biotin complex-peroxidase method with monoclonal antibody to human IgG4  on sections from paraffin-embedded tissue.The renal biopsy was examined specifically for features suggestive of IgG4-RKD+, including presence of TIN, lymphoplasmacytic infiltration, as well as tubulointerstitial presentations on light microscopy, glomerular light microscopy abnormalities, glomerular or tubular basement membrane (TBM) deposits on IF or EM. IgG4 staining was done and the number of positive plasma cells/hpf were calculated.t test for differences for continuous, normally distributed data; continuous, non-normally distributed data were analyzed by the Mann–Whitney test. Categorical variables were processed by X2 or Fisher’s exact tests. Logistic regression analysis with enter method was performed to compare the IgG4-RKD+ and IgG4-RKD− patients. Factors with P < 0.05 and clinical significance in the univariate analysis were included in the multivariate analysis. P < 0.05 was considered to be statistically significant.Using Stata software , data were analyzed by descriptive methods, with standard summary statistics including mean (S.D.), median, interquartile range (IQR), and proportions. We performed the Student’s P = 0.048; 60 vs 56, P = 0.013, respectively). Male to female ratio of IgG4-RKD+ patients is significantly higher .Demographic details of all the 450 IgG4-RD patients were outlined in Table P < 0.001). Detailed organ involvement between IgG4-RKD + and IgG4-RKD− groups was shown in Fig. P = 0.023) and gallbladder  were more common in IgG4-RKD+ patients.As shown in Table P = 0.007) and Hb  were significantly lower in the IgG4-RKD+ group.Disparities in laboratory features between the IgG4-RKD+ and IgG4-RKD− groups were indicated in Table 2 . The level of serum creatinine varied from 61 to 98µmol/L at baseline. The median blood urea nitrogen was 6.7 mmol/L . Fourteen (26.4%) of the 53 IgG4-RKD+ patients presented with proteinuria (1+ or greater on dipstick). Approximately 40% of IgG4-RKD+ patients presented with urine occult blood. Positive urinary white blood cells (urinary white blood cells > 14/µl) excluding urinary infection were detected in 10 (18.9%) patients.As presented in Table The renal tubular function was also impaired. Urine specific gravity was reduced in 5.7% of the 53 patients. Among the 12 IgG4-RKD+ patients who had specific renal tubular function tested, the three indexes of β2-MG, NAG and RBP were simultaneously elevated in 6 (50%) patients. The median β2-MG, NAG and RBP of all the IgG4-RKD+ patients were 3172.1 µg/L , 21.1 U/L  and 1.2 mg/L , respectively, which were all higher than the normal range.P = 0.020), ≥ 3 organs involvement , pancreas , gallbladder , , high level of ESR  were associated with higher rate of IgG4-RKD + in univariate analysis. Female , serum C3 levels  and Hb  were the protective factors of IgG4-RKD + .As shown in Table P = 0.019), ≥ 3 organs involvement , and serum C3 levels  remained significant after multivariate analysis  patients had TIN. TIN in 1 case (16.6%) was associated with glomerular disease. Membranous nephropathy was the cause of glomerular disease in this case.14.All the patients with TIN had a lymphoplasmocytic (LPC) infiltrate with fibrosis. The LPC infiltration was diffuse in 3 patients and patchy in the other 3 patients. In all of the 6 patients with TIN, IgG4 staining demonstrated > 10 IgG4+ plasma cells per high-power field (in the most concentrated area), and all these patients fulfilled the Raissian criteria for IgG4-TINWe used contrast-enhanced CT to identify radiological abnormalities in IgG4-RKD+ patients except those with renal dysfunction. Fifty of the 53 IgG4-RKD+ patients exhibited characteristic findings of the kidney radiology. Among them, 14 patients were presented with more than one kind of lesion. The most common finding is multiple, often bilateral, hypodense lesions in 31 (58.5%) IgG4-RKD+ patients, which are called small cortical hypodense nodules  and Mexico (24.6%)16, but similar to that of UK study11. The heterogeneity of IgG4-RKD+ definition and ethnicity in various studies may explain for this diversity. The following organs were found more commonly involved in IgG4-RKD+ patients, including salivary gland, lymph nodes and pancreas. In addition, multi-organ involvement was common in IgG4-RKD+ patients. Therefore, it is necessary to perform a general checkup to obtain a comprehensive view of the patients especially for patients with IgG4-RKD+.IgG4-RD is manifested by typical clinical features, including tumor-like lesions, dense infiltration with IgG4-positive plasma cells, and extensive fibrosis of multiple organs. There is a great variability of disease manifestations for IgG4-RD, and the identification of different IgG4-RD subgroups is crucial, as a consequence of significant disparities in the characteristics of IgG4-RD regarding different organs17, which may explain for the association between involvement of 3 or more organs and IgG4-RKD+. Renal involvement may appear as an intrinsic kidney disease (IgG4-RKD+) or as a consequence of ureteric obstruction from retroperitoneal fibrosis (IgG4-RPF). IgG4-RPF often concentrated in the periaortic region and ureters can be entrapped, leading to hydronephrosis and renal injury. Therefore, it is necessary to distinguish between the kidney lesions from IgG4-RKD+ and IgG4-RPF. Similar to previous studies18, male predominance in IgG4-RKD+ may be explained by the viewpoint that female patients were more likely to present with superficial organ involvement, while male patients with internal organ involvement.Male sex, involvement of three or more organs, and low serum C3 level were risk factors for IgG4-RKD+ in IgG4-RD patients. IgG4-RD is a multi-organ immune-mediated condition that could influence almost any organ system in the body. More involved organs may suggest the higher activity of disease. In most cases, IgG4-RKD+ is diagnosed in the context of known extrarenal IgG4-RD or active status of IgG4-RD. With progressive renal decline or detection of characteristic radiological features when evaluating extrarenal IgG4-RD, kidney involvement became evident19. Only about 16–34% of IgG4-RD patients have low serum complement levels, despite that hypocomplementemia is a feature of IgG4-RD. Nevertheless, more than 50% of patients with active IgG4-TIN have low concentration of complement17. Therefore, hypocomplementemia is considered an important serological feature of the disease13. In our study, hypocomplemenemia was found in 32 (60.4%) of IgG4-RKD+ patients, which is similar to previous studies. Wang Rong et al. found that complement activation may promote the development of IgG4-RKD+20. Therefore, this study added insights into the hypocomplementemia in IgG4-RKD+ patients. Low serum C3 level was found a risk factor for the development of IgG4-RKD+. Hypocomplementaemia is not characteristic feature of most IgG4-RD patients, which often suggests the existence of IgG4-RKD+, thus scrutiny is necessary.There are some interpretations for the association of low serum C3 levels and IgG4-RKD+. The first descriptions of IgG4 TIN was previously described as “idiopathic hypocomplementemic tubulointerstitial nephritis” with extensive tubulointerstitial deposits21. In our cohort, the renal function was impaired manifesting as the reduced eGFR, elevated blood urea nitrogen, elevated serum creatine and abnormal specific renal tubular function test. It could be attributed to IgG4-related TIN in the patients, or to the glomerular disease. IgG4-related TIN occurred in the vast majority of IgG4-RKD+ patients, and MGN was reported less than that. Consistent with the rates in previous studies, IgG4-related TIN occurred in all the 6 IgG4-RKD+ patients who had received renal biopsy. In the urinalysis in IgG4-related TIN, we could find typically mild to moderate proteinuria, as well as occasionally the presence of white blood cells17, which was also accordant with our result. For IgG4-RD patients, it is necessary to carry out urine routine test and renal function test (both glomerular and tubular function), in order to timely detect glomerular and renal tubular lesions.In previously reported studies, kidney function in IgG4-RKD+ patients varies from normal to renal failure, and the development of renal dysfunction also varies from relatively acute to slowly progressive22. CT was the most common mode of renal imaging, including PET-CT, which is increasingly used. PET-CT could contribute to excluding malignancy with little radiative damage. Moreover, PET-CT is helpful for discovering the involvement of some silent lesions, however, its cost should also be taken into account.Main abnormalities on renal imaging were revealed in a total of 42 (79.2%) of IgG4-RKD+ patients: multiple low-density nodules, hydronephrosis and thickening of renal pelvic wall. Similar with previous studies, there were also some other imaging manifestations in our cohort, including diffuse patchy involvement of the bilateral kidneys and rim-like lesion of the kidneyOne of the limitations of this study is its retrospective nature, indicating that some affected organs may be neglected, although most patients have undergone general examinations, including FDG-PET. Moreover, only a small number of IgG4-RKD+ cases were diagnosed based on renal biopsy. Compared to biopsy from superficial tissue, there would be higher risk of iatrogenic trauma when patients receive deep kidney biopsy, thus some patients would not accept it. In addition, although our study has the relatively largest sample size yet, the number of patients is still small. We should cautiously interpret the results.In summary, we have specified demographic, clinical, and laboratory differences between IgG4-RKD+ patients and IgG4-RKD− patients. IgG4-RKD+ patients had older age at onset and older age at diagnosis. The male to female ratio of IgG4-RKD+ patients is significantly higher. The most commonly involved organs of IgG4-RKD+ patients were salivary gland, lymph nodes and pancreas. Male sex, involvement of three or more organs, and low serum C3 level were risk factors for IgG4-RKD+ in IgG4-RD patients. These findings indicate potential differences in pathogenesis of these two phenotypes with or without kidney involvement.


Metabolic syndrome (Met-S) constitutes the risk factors and abnormalities that markedly increase the probability of developing diabetes and coronary heart disease. An early detection of Met-S, its components and risk factors can be of great help in preventing or controlling its adverse consequences. The aim of the study was to determine the prevalence of cardio-metabolic risk factors in young army recruits from Saudi Arabia. A total of 2010 Saudis aged 18–30 years were randomly selected from groups who had applied to military colleges. In addition to designed questionnaire, anthropometric measurements and blood samples were collected to measure Met-S components according to the International Diabetes Federation (IDF) criteria. Met-S prevalence was 24.3% and it was higher in older subjects than the younger ones. There were significant associations between Met-S and age, education level and marital status. The most common Met-S components were high fasting blood sugar (63.6%) followed by high blood pressure  and high body mass index (57.5%). The prevalence of pre-diabetes and diabetes were found to be 55.2% and 8.4%, respectively. Hypertriglyceridemia was found in 19.3% and low levels of high-density lipoproteins (HDL) in 11.7% of subjects. In conclusion, there is a high prevalence of Met-S in young adults of Saudi Arabia. There is a need for regular monitoring of Met-S in young populations to keep them healthy and fit for nation building. It is also important to design and launch community-based programs for educating people about the importance of physical activity, cessation of smoking and eating healthy diet in prevention of chronic diseases. Metabolic syndrome (Met-S) is defined as a cluster of cardiovascular disease (CVD) risk factors that typically include central obesity, elevated blood pressure (BP), impaired glucose metabolism, and dyslipidemia. Met-S is a major risk factor for cardiovascular disease  and typeSoldiers are typically young and physically active but they are not devoid of CVD risk when they are overweight or obese ,8. SoldiMilitary personnel as an occupational group are at higher risk of stressful conditions, exposure to death or harmful agents as well as imposed restriction on food selection or availability. Having an ideal body weight and fitness is a fundamental principle in military forces recruitment. Unfortunately, there are scarce data about the prevalence of CVD risk factors and almost no research on the prevalence of Met-S in young army recruits from Saudi Arabia. We therefore examined the prevalence of Met-S and associated risk factors in army recruits who are expected to have a better fitness level than the general population.A total of 2010 young Saudi men aged 18–30 years who applied for recruitment to Saudi armed forces were included in this study. An estimated 4000 applicants are annually invited to participate in the recruitment process. The power analysis based on a previous prevalence study in general Saudi population  and usinAccording to the International Diabetes Federation (IDF) definition, subjects were considered to have Met-S if they had central obesity (defined as waist circumference > 94 cm), plus two of the following four factors: raised fasting plasma glucose > 100 mg/dL (5.6 mmol/L), or previously diagnosed type 2 diabetes; systolic blood pressure (BP) > 130 or diastolic BP > 85 mm Hg, or treatment of previously diagnosed hypertension; high density lipoproteins (HDL) < 40 mg/dL (1.0 mmol/L) or specific treatment for this lipid abnormality; triglycerides (TG) level > 150 mg/dL (1.7 mmol/L) or specific treatment for this lipid abnormality.2), overweight (≥25–29.99 kg/m2) and obese (≥30 kg/m2) , total cholesterol, HDL and TG were analysed using a Roche Hitachi 902 autoanalyzer . Blood samples from each recruitment centre were transported to Prince Sultan Military Medical City for biochemical analysis. Blood samples were centrifuged at 1500× p value < 0.05 was considered as statistically significant. The data were analysed by using the SPSS statistical package version 14 . Mean and standard deviation (SD) were calculated for parametric data, while categorical data were represented by number and percentage. The chi-square test was used for comparison between the Met-S and without Met-S groups. A The anthropometric and demographic characteristics as well as blood pressure and pulse rate are summarized in 2 BMI (46.2%) despite the young age of these participants. More than a quarter of total participants were underweight (28.6%), while only limited number of subjects (14.0%) had normal body weight (The most striking finding of study was the high frequency of subjects with >30 kg/my weight . One thiy weight .The answers of subjects to queries about their awareness of hypertension and diabetes as well as any medication are summarized in The results of serum biochemistry including fasting blood sugar (FBS) and lipid profile are given in For the diagnosis of Met-S, six different triplets of associated components were used as a standard protocol. Specific cut-off values of these triplet parameters were used to filter subjects with Met-S. Among these triplets, BMI/FBS/BP identified 12.9% subjects affected with Met-S, followed by BMI/FBS/TG (7.8%), BMI/FBS/HDL (5.3%), BMI/BP/TG (4.5%), BMI/BP/HDL (2.5%) and BMI/TG/HDL (1.8%) . The aggp = 0.001), education level (p = 0.001) and marital status (p = 0.003); however, monthly income (p = 0.761) was not associated with Met-S  and the associated risk factors in young men, as a sector in a population. In this study, Met-S was found in 24.3% of young adults . WorldwiThis study showed a significant association between age and Met-S . DemograWe observed that a large number of participants were overweight. Obesity continues to rise in Arab population with an alarming rate, while females are more prone to becoming obese than males. Obesity is a progressively significant public health problem and is considered a major risk factor for diet-related chronic diseases including Met-S, T2DM, hypertension, stroke and certain forms of cancer . AbdominIn our study, mean pulse rate was found to be 84.77 ± 13.97 per minute and most of the subjects had a pulse rate above 72 beats/min. Al-Qurashi et al.  reportedThe majority of our subjects had fasting blood sugar (FBS) greater than 99 mg/dL. A nationwide, population-based cohort of 53,370 participants from Saudi Arabia revealed that abnormal glucose metabolism has reached an epidemic state in Saudi Arabia, where one-third of the population is affected and half of diabetic cases were unaware of their disease . It is iMilitary personnel are considered healthy and physically fit adults who may be at low risk for developing a cardio-metabolic disease, as military service requires adherence to body composition, fitness and medical standards . HoweverIn conclusion, the prevalence of Met-S was found to be 24.3% of young participants in this study, which is a matter of concern. As we also observed a direct association between age and Met-S, it is expected that the prevalence of Met-S in older populations would be much higher. Elevated FBG was the most prevalent component of Met-S which might be indicative of the first detectable Met-S component factor in several adults. Blood pressure and BMI would also help in the screening of Met-S. It is known that long-term Met-S results in numerous complications; however, Met-S is preventable and controllable with lifestyle changes. Regular screening, follow-up studies and interventions would reduce the incidence of Met-S and improve the fitness of youngsters. The findings of this study serve as the latest survey of Met-S status in a young Saudi population. The results will help in designing preventive measures as well as public awareness programs for minimizing the incidence of Met-S and its associated diseases.


Veterinary antibiotics are widely used to treat bacterial diseases in various species of animals. However, despite the importance of these chemotherapeutic agents, their indiscriminate or extensive use can pose dangers to the animals or humans that consume edible tissues from animals contaminated with antibiotic residues. Therefore, concerns regarding their appropriate and judicious use in animals are of public health significance. This is because of the tendencies of developing resistance to targeted microbes and the ability of the parent compound or its metabolites to persist as residues in the animal tissues. This study aimed to determine the frequency and pattern of antibiotic usage and ascertain the level of awareness of clinicians on the judicious use of antibiotics at the University of Maiduguri Veterinary Teaching Hospital, Maiduguri, Borno State, Nigeria.Data related to the administration of antibiotics in all species of animals presented for treatment from January 2009 to December 2018 were obtained from the hospital archives, with permission from the office of the hospital directorate. The diseases, hospital units, antibiotics used, and years were parameters that were recorded for each case. Furthermore, 47 questionnaires were administered to clinicians who render services to the hospital.A total of 63.9% of all cases brought to the hospital within the 10 years under study were infectious, and as such, were treated with antibiotics. The highest recorded use of antibiotics was observed in the poultry unit (38.4%), followed by the large animal unit (24.1%), with the lowest used recorded in the ambulatory unit (9.3%). Furthermore, regarding the antibiotics used, oxytetracycline had the highest occurrence (55%), followed by penicillin-streptomycin combination (12.2%), with the lowest being metronidazole (0.30%). The highest number of cases treated with antibiotics was recorded in 2018 (22.5%), and the lowest was recorded in 2014 (1.3%). Regarding the questionnaire administered to the clinicians, 78.7% of the respondents preferred oxytetracycline as their drug of choice, whereas only 2.1%, 4.3%, 2.1%, and 4.3% preferred amoxicillin, penicillin, streptomycin, and penicillin-streptomycin, respectively. Moreover, 65.9% of the respondents used a particular antibiotic because of its availability at the hospital, 8.5% because of cost, and 27.7% because of clinician preference. Furthermore, 74.5% of the clinicians offered palliative intervention while awaiting laboratory reports, whereas 8.5% treated the animals without requesting laboratory analyses.In this study, oxytetracycline was found to be the most used antibiotic for treating infectious diseases at the hospital because of its availability. The observed pattern appeared in the following order of frequency: Oxytetracycline, penicillin-streptomycin combination, neomycin, erythromycin, amoxicillin, tylosin, streptomycin, and gentamicin with metronidazole being the least frequent. There might also be antibiotic resistance, which requires a change to another antibiotic because of the lack of response to the initial antibiotic. Non-judicious antibiotic use can also have a negative impact on public health because of the development of multidrug-resistant “superbugs” and the problem of drug residue. Antibiotics are compounds that are synthesized by various microorganisms  and may kill or inhibit multiplying bacteria rapidly . An antiThe worldwide increase in the use of antibiotics as an integral part of livestock and poultry production to treat and prevent infectious diseases and as growth promoter has led to the development of antibiotic resistance over the years ,6. When This study aimed to determine the frequency and pattern of antibiotic usage and to ascertain the level of awareness of clinicians on the judicious use of antibiotics at the University of Maiduguri Veterinary Teaching Hospital (UMVTH), Maiduguri, Borno State, Nigeria.This study was approved by the Directorate of the Veterinary Teaching Hospital, University of Maiduguri, Borno State, Nigeria. The consent of the veterinarians working at the hospital was also obtained before the questionnaires were administered.This study was achieved by obtaining relevant data from the hospital archives related to the administration of antibiotics in all species of animals that were presented for treatment from January 2009 to December 2018. The disease, units, antibiotics used, and years were parameters that were recorded for each case. Furthermore, 47 questionnaires were administered to clinicians who render services to the hospital. The survey was carried out at the UMVTH, Maiduguri, Borno State, Nigeria. Established in 1983, the UMVTH is the only veterinary teaching hospital in the North-Eastern area of Nigeria. It sometimes partners with national and international organizations because of its outstanding performance. It also receives referrals from public veterinary hospitals, private veterinarians, and clinics.® 2013 .The data generated were analyzed based on descriptive statistics using Microsoft Office ExcelFrom the survey performed here, a total of 1,580 cases were documented in the UMVTH over the 10 years under study, with 1010 of the cases being infectious and, as such, being treated with antibiotics; that is, antibiotics were administered to 63.9% of all cases brought to the hospital. The highest use of antibiotics  was recoThe questionnaire administered to the clinicians revealed that 78.7% of the respondents preferred oxytetracycline as their drug of choice, whereas only 2.1%, 4.3%, 2.1%, and 4.3% preferred amoxicillin, penicillin, streptomycin, and penicillin-streptomycin, respectively. Moreover, 65.9% of the respondents used a particular antibiotic because of its availability at the hospital, whereas 27.7% of the antibiotic usage was based on clinicians’ preferences. In addition, only 4.3% of the clinicians reported attending a seminar on the prudent use of antibiotics and rational approach to prescription organized by the UMVTH. Furthermore, 42.6% of the clinicians were aware of the guidelines of the Veterinary Council Nigeria (VCN) on the judicious use of antibiotics in veterinary hospitals, whereas 57.4% of them were unaware of them. The questionnaire also showed that 53.2% of the respondents had to change their line of treatment because there was no response to the initial treatment. This might have been caused by possible resistance of the offending microbe to the antibiotic being used. The records revealed that there was a remarkable positive outcome after changing the line of treatment to another antibiotic. The highest recorded antibiotic switch was from oxytetracycline to other antibiotics, such as ceftriaxone, streptomycin, and cotrimoxazole. Moreover, 74.5% of the clinicians provided supportive treatment while waiting for laboratory reports, whereas 8.5% treated the animals without requesting laboratory analyses. The questionnaire showed that 40.4% of the respondents who sent samples to the laboratory did not request a sensitivity test for the isolated organism before instituting antibiotic therapy.et al. [et al. [et al. [From the recorded cases that were presented to the UMVTH during the period under study, about two-thirds of the cases were infectious and were, therefore, treated with antibiotics. Other cases were non-infectious, such as poisoning, metabolic disorders, and fractures. The prevalent usage of antibiotics  was largely based on the frequency of use rather than the volume constituting the dose of the drug. Oxytetracycline was mostly used in large animals, followed by poultry and small animals . This miet al. , who rep [et al.  reported [et al.  reportedFurthermore, from this survey, it was observed that  most cliMost veterinary national and international conferences are now focused on drug resistance and residues because it has become a global concern for human and animal health. The recent Nigerian Veterinary Medical Association conventions and VCN continuing education (2016-2018) have been focused mostly on this global epidemic. A list of about 200 essential veterinary drugs, pesticide chemicals, and biologicals has been published by the VCN and referred to as the Nigerian Veterinary Formulary. Moreover, Aliu  reportedThe findings of this study revealed that oxytetracycline was the most used antibiotic at the UMVTH, Maiduguri, Borno State, Nigeria, followed by a penicillin-streptomycin combination . This waND and KDM: Designed the study, wrote the manuscript, and prepared tables and figures. BU: Supervised the study, reviewed, and edited the manuscript. IJO and LS: Assisted in the issuance and compilation of the questionnaires and statistical analysis. All authors read and approved the final manuscript.


Immunoglobulin G4-related lung disease (IgG4-RLD) is a rare entity. We retrospectively analyzed the clinical and histopathological characteristics of patients with pathologically confirmed IgG4-RLD to improve the diagnosis rate and reduce the risk of misdiagnosis.We screened the pathological reports of 4838 patients with pulmonary surgery and/or biopsy specimens from April 2017 to April 2021 at Sun Yat-Sen Memorial Hospital affiliated with Sun Yat-Sen University, and specimens from 65 patients with suspected IgG4-RLD were subjected to immunohistochemical staining for IgG4 and IgG. Finally, 10 patients with definite IgG4-RLD that was pathologically confirmed were enrolled and analyzed.18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) imaging revealed that 5 patients had a mixed type, 3 patients had the solid nodular type, and 2 patients had the bronchovascular type. All pulmonary masses and large nodules with solid patterns had spiculated margins and inhomogeneous enhancement with or without pleural indentation and a lobulated appearance. Abundant lymphoplasmacytic cell infiltration and fibrosis were observed in all patients. The expression of IgG4 and IgG was upregulated in the pulmonary sections. Seven patients were treated with glucocorticoids with or without additional immunosuppressants and responded well.The incidence of pathologically confirmed IgG4-RLD was 0.2% (10/4838). The ten patients had an average age of 59.7 years at diagnosis, and the male-to-female ratio was 9:1. The initial clinical manifestations were nonspecific, and cough was the most common symptom (4/10). More than one organ was involved in most patients (8/10), and mediastinal/hilar lymph node involvement was often observed (7/10). Serum IgG4 was analyzed in 6 patients and found to be elevated. Serum tumor marker levels were within the normal range or were slightly elevated. Computed tomography (CT) of the chest and/or The results of our study suggest that multiple imaging findings, an elevated serum IgG4 concentration, and no significant increase in serum tumor biomarkers could provide diagnostic support for IgG4-RLD, especially for isolated IgG4-RLD or IgG4-RLD that includes other organ involvement that does not aid in establishing the diagnosis. Immunoglobulin G4-related disease (IgG4-RD) is a recently recognized chronic fibro-inflammatory condition with a histopathological hallmark of dense lymphoplasmacytic cell infiltration, storiform fibrosis and obliterative phlebitis . Almost This retrospective study was conducted at Sun Yat-Sen Memorial Hospital affiliated with Sun Yat-Sen University. We reviewed the pathological reports of 4838 patients who underwent biopsy and/or lung resection between April 2017 and April 2021, and we used the electronic pathological record system to obtain these data. The levels of IgG4 and IgG were assessed by immunohistochemical staining of lung tissue specimens from 65 patients with suspected IgG4-RLD. According to the 2012 international pathological consensus of IgG4-RD [ ≥ 2 items from the list of histopathological features.The number of IgG4 + plasma cells was > 50 cells/high-power field (HPF).An IgG4 + /IgG + plasma cell ratio > 40%.Histopathologically highly suggestive criteria:2.At least 1 item from the list of histopathological features.The number of IgG4 + plasma cells was > 50 cells/HPF from the lung surgical specimens, > 20 cells/HPF from the biopsy, or an IgG4 + /IgG + plasma cell ratio > 40%.Additional evidence: A serum IgG4 concentration > 2.01 g/l according to the detected range of our hospital or other organ involvement proven by imaging or histopathological examinations.Histopathologically probable criteria:3.Histopathologically insufficient criterion: Any case that does not conform to the above two categories.The histopathological diagnostic criteria were based on the 2012 international pathological consensus of IgG4-RD [Hematoxylin and eosin (H&E) staining and immunohistochemical staining for IgG4 and IgG were conducted at the Department of Pathology in our hospital. Two pathologists (Ximing Shen and Zhanghai He) independently reassessed the lung tissue sections. The sections that had immunohistochemical staining for IgG4 and IgG were observed under low-power microscopic magnification (× 40) to identify three different hot spots of IgG4 + plasma cells. Then, the numbers of IgG4 + plasma cells were determined in the three fields using HPF counts (× 400), and the average was taken for each investigator. The same three fields were used to count the number of IgG + plasma cells, and then the IgG4 + /IgG + plasma cell ratio in the plasma cells was calculated. The numbers obtained from the two researchers were averaged, and this average was presented as the final result. However, when significantly different counts for a section were obtained, a double-headed microscope was used to reach an agreement.18F-fluorodeoxyglucose positron emission tomography-computed tomography (18F-FDG PET-CT) imaging at baseline. A professional radiologist (Yuxiang Liu) carefully reviewed these images. According to the predominant radiological abnormality on CT examination, the patients were divided into groups based on five types as mainly proposed by Inoue and colleagues: solid nodular, alveolar consolidative, round ground-glass opacity (GGO), bronchovascular and alveolar interstitial [All included patients underwent thoracic computed tomography (CT) and/or rstitial . The solrstitial –8. When rstitial .The follow-up period ended in October 2021. All 10 patients with IgG4-RLD completed follow-up, with an average of 27 months (range 6–54 months). The clinical, serological and imaging data of these patients were documented in detail at each follow-up visit.The clinical and serological features of the 10 patients with IgG4-RLD are displayed in Table 18F-FDG PET-CT findings revealed that 5 patients had a mixed type, 3 patients had the solid nodular type, and 2 patients had the bronchovascular type. Eight patients had pulmonary masses and/or nodules with solid patterns. Of these 8 patients, 3 patients had a single lung mass, and 5 patients had large lung nodules, while all of the patients had multiple small nodules mostly scattered in all of the lung lobes. In addition to a lobulated shape in 1 patient and pleural indentation in 4 patients, these pulmonary masses and large nodules had spiculated margins and heterogeneous densities. The pulmonary nodules were bilateral in 6 patients, while 2 patients had lesions confined to the right lung. The features of the masses or nodules of the 8 patients are summarized in Table The pulmonary imaging characteristics of the 10 patients are summarized in Table The incidence of pathologically confirmed IgG4-RLD was 0.2% 10/4838). All of the lung tissue specimens from the 10 patients with histopathologically confirmed IgG4-RLD were available. Most of the lung specimens appeared gray-white or gray-yellow in color. H&E staining revealed chronic pulmonary inflammation: dense lymphoplasmacytic cell infiltration  and fibrosis . Representative images are shown in Fig. 8. All ofSeven patients were treated with glucocorticoids with or without other immunosuppressants; 5 patients were treated with prednisone only, and 2 patients were treated with prednisone combined with cyclophosphamide. Two patients underwent lung surgery and did not take prednisone or immunosuppressive drugs. One patient with mild disease received only symptomatic treatment. The symptoms improved in all of the patients after treatment and before they were discharged from the hospital. All of the patients completed several follow-up visits as required. The serum IgG4 level decreased gradually in the 6 patients who had initially elevated serum IgG4. However, in 1 patient, the serum IgG4 level increased again when the prednisone dosage was reduced. Follow-up chest CT was performed in all patients. Six patients showed improvement on chest CT, with nodule or mass shrinkage. Two patients showed no changes in the size of pulmonary nodules or the extent of bronchovascular bundle thickening. Two patients relapsed and presented new pulmonary nodules, but these nodules disappeared after restarting prednisone therapy combined with additional immunosuppressive drugs.IgG4-RLD is a rare condition that is not well understood, and the incidence of IgG4-RLD is unknown. Our study showed that the incidence of pathologically confirmed IgG4-RLD was 0.2% in our hospital. Herein, we analyze and report the clinicopathological characteristics of the 10 patients with pathologically confirmed IgG4-RLD based on a single-institution experience.In our study, there were several important findings: (1) Elevated serum IgG4 was observed for all patients in whom it was measured, and there were no significant elevations in serum tumor markers in the patients with IgG4-RLD. (2) The clinical manifestations and radiological findings were nonspecific. Some patients were initially asymptomatic; the pulmonary lesions in these patients were incidentally identified on chest imaging examinations. Moreover, because the results on imaging often mimic pulmonary malignancy, patients with IgG4-RLD might be misdiagnosed with lung cancer and undergo unnecessary lung resection. The involvement of other organs, as demonstrated by radiological or histopathological findings, can also be helpful for diagnosis. However, when the lung is independently affected or there are lung lesions in combination with the involvement of other anatomical sites that do not help establish a definite diagnosis, the diagnosis of IgG4-RLD is very challenging. Thus, we suggest a brief diagnostic strategy to distinguish IgG4-RLD from lung carcinoma: multiple findings on imaging, an increase in serum IgG4, and no significant increase in serum tumor biomarkers. (3) Most patients responded well to prednisone with or without other immunosuppressants.The clinical symptoms of IgG4-RLD are nonspecific and mainly depend on the location of the pulmonary lesions. Our study showed that the initial respiratory symptoms were cough, chest or back pain, hemoptysis and low-grade fever. Pulmonary abnormalities were occasionally found by chest radiological examinations in asymptomatic patients. This phenomenon has also been reported in previous studies to various extents –11.In 2009, Inoue and colleagues proposed four major types based on the predominant radiological abnormality: solid nodular, round-shaped GGO, bronchovascular and alveolar interstitial . In addiTo meet this challenge, we should focus on the following points, especially when patients present with only lung involvement or other organ involvement that does not help establish a definitive diagnosis: (1) In addition to pulmonary masses and/or large nodules, attention should be given to the radiological manifestations of the other subtypes, as mentioned above, which may offer some support for a diagnosis of IgG4-RLD. (2) In this case, serological testing for IgG4 should be performed. Serum IgG4 has high diagnostic value for IgG4-RD, and its concentration has a positive correlation with the number of organs involved . Wang anGlucocorticoids are commonly used as the first-line treatment of IgG4-RD, and most patients respond well to this intervention. However, there is currently no universal consensus on the duration and tapering regimens of glucocorticoids. Glucocorticoids can be combined with immunosuppressive drugs as a first-line treatment when there are factors for recurrence, such as multiple organ involvement, elevated serum IgG4 and immunoglobulin E levels and increased eosinophil counts in the peripheral blood . ConsistThe strength of our study is that to our knowledge, we are the first to report the incidence of histopathologically confirmed IgG4-RLD. Furthermore, we analyzed the clinicopathological characteristics of the patients with definite IgG4-RLD based on the histopathological diagnosis, and a brief diagnostic approach to distinguish IgG4-RLD from pulmonary cancer was suggested. However, the present study has some limitations. First, the generalizability of these findings may be questionable because our study is a retrospective single-center study with only a small number of cases and inherent selection bias. Large-scale prospective studies are needed for further confirmation. Second, our follow-up time was not sufficiently long, so the entire course of IgG4-RLD could not be well investigated.IgG4-RLD is a rare disorder that often mimics lung cancer. For clinicians, it is a great challenge to distinguish IgG4-RLD from lung cancer, especially when a single lung is affected or if the involvement of other organs does not provide diagnostic support. This study analyzed the clinical characteristics of 10 patients with pathologically confirmed IgG4-RLD in our hospital. Our results suggest that multiple imaging findings, elevated serum IgG4 level and no significant increase in serum tumor biomarkers could provide diagnostic support for IgG4-RLD, and subsequent experimental steroid therapy could be given to further confirm the diagnosis. If not, lung biopsy can be performed to make a definitive diagnosis.


Whereas the isomer ratio of the obtained cage mixture, consisting of up to 42 isomers, is insensitive to temperature and solvent, the quantitative convergence from the mixture to a single isomer is accomplished upon encapsulation of a large spherical guest, namely fullerene C60. The observed isomerization with other guests depends largely on their size and shape . Besides the unusual guest-induced convergence, the present cage mixture displays the strongest guest emission (ΦF = 68%) among previously reported MnLm cages and capsules, upon encapsulation of a BODIPY dye in water.Introduction of atropisomeric axes into a bent bispyridine ligand leads to the quantitative formation of a complex mixture of atropisomeric M 2L4 cages is shown to undergo perfect convergence to a single isomer upon encapsulation of spherical C60 in water. Moreover, the cage mixture displays very strong guest emission upon encapsulation of a BODIPY dye.A complex mixture of atropisomeric M Treatme cages 2 . Althoug2L4 structure to examine its desymmetrization and convergence. It has been established that bent bispyridine ligands with a virtual C2v symmetry generate M2L4 cages or capsules as a single isomer upon complexation with metal ions , is anticipated to be present as an equilibrium mixture of up to 42 isomers 2, and AgNO3 (in a 2 : 1 : 2 ratio) in DMSO-d6 for 1 h at room temperature -linked cage 2 as an isomeric mixture in equilibrium. The exclusive formation of M2L4 assemblies 2 was unambiguously confirmed by ESI-TOF MS analysis: prominent peaks were observed at m/z 759.9, 1033.9, and 1582.3, assignable to the [2 – n·NO3−]n+ species -analogue 2′ was formed quantitatively and its M2L4 structure was confirmed by NMR and MS analyses.11 The existence of various isomers of 2′ was also established by the complicated and broadened 1H NMR signals  is surrounded by eight naphthalene panels and the cavity diameter is 1.3 nm. Although the cavity shape and size are almost identical to those of anthracene-based M2L4 capsule 3 reported previously  and temperature , guest encapsulation allowed the complex mixture to convert into a single isomer in water. When a simple planar and hydrophobic guest, triphenylene , was mixed with a D2O solution of 2 (0.6 mM) at room temperature for 1 h . The ESI-TOF MS analysis of the product clearly supported the formation of 1 : 2 host–guest complex 2·(Tp)2  and bowl-shaped corannulene (Cor) with cage mixture 2 gave rise to host–guest complexes 2·Ad and 2·(Cor)2 in a quantitative manner, respectively, under the same aqueous conditions 2 guests were estimated to be 75 and 82, respectively 2  ions, and excess Cor in D2O at room temperature for 7 h  hinges and the pyridyl groups are fixed under these conditions.Next, the treatment of small spherical adamantane 2 . Notewor Fig. S30.11 The f60 (C60) into cage 2. Mixing of cage 2 with excess C60 in D2O at 100 °C for 24 h yielded 1 : 1 host–guest complex 2·C60 exclusively. Intense ESI-TOF MS peaks at m/z = 940.2 and 1274.2 were assignable to [2·C60 – n·NO3−]n+ species .9 The broadened, new UV-visible absorption bands derived from the guest were also found around 400–730 nm  and shape complementary guest molecules.The quantitative conversion of the mixture into a single isomer was accomplished upon incorporation of spherical fullerene C Fig. S32, in a ma Fig. S36.16 In sh2·C60 was eventually determined by X-ray crystallographic and theoretical analyses.11,17,18 As we expected, the crystal structure showed that one molecule of C60 is fully captured by the cage-shaped M2L4 framework of 2  on the basis of the present crystal structure indicated that the energy of the all-syn isomer  between the polyaromatic ligands, in contrast to previous M2L4 capsule 3 with an anthracene-based, closed shell.9 Preliminary host–guest studies showed the selective binding of one molecule of functionalized fullerenes  by the present cage in water -cage 2′ displays very strong guest emission upon encapsulation of a BODIPY dye in water.19 After stirring a mixture of cage 2′ and water-insoluble, pentamethyl boron-dipyrromethene PMB (9 equiv.) in D2O at 80 °C for 1.5 h  with respect to those of free PMB in CH3CN and their intensity indicated the encapsulation efficiency being ∼25%. The optimized structure of 2′·PMB (R = –H) suggested that a slightly bent PMB framework is fully accommodated in the polyaromatic shell of 2′  from a 1 : 1 host–guest complex, composed of anthracene-based capsule 3 and PMB in water.7 Notably, the aqueous solution of 2′·PMB emitted much stronger green fluorescence with a quantum yield of 68% at λmax = 514 nm, upon irradiation at 500 nm . To the best of our knowledge, this represents the strongest guest emission in coordination host compounds reported so far.7 As compared to capsule 3 with a relatively rigid cavity,9 the flexible naphthalene-based cavity of 2′ is able to adjust to the shape of the bulky PMB guest .19Host–guest complexes featuring high emissivity in water have attracted considerable attention related to biomolecular sensors. However, the majority of coordination cages and capsules disturb guest emission upon encapsulation, owing to the heavy metal effect.t 500 nm . The banMB guest , which r2L4 cages into a single isomer by an external stimulus. The cage mixture including up to 42 isomers was generated upon incorporation of two atropisomeric axes into the bent bispyridine ligands of a common and highly symmetrical M2L4 structure. Unusual convergence of the mixed isomers was demonstrated upon encapsulation of guest molecules. Particularly, the encapsulation of a fullerene guest led to the quantitative formation of a single isomer, due to its size and shape complementarity to the spherical host cavity. Thus, the present system can be regarded as a novel dynamic combinatorial library capable of incorporating large guests up to 1 nm. The isomer structure  of the M2L4 cage was fully characterized by NMR, MS, UV-visible, X-ray crystallographic, and theoretical analyses. As an additional host function, the cage mixture encapsulated a fluorescent BODIPY dye and the resultant 1 : 1 host–guest complex exhibited intense guest emission (ΦF = ∼70%) in water. We believe that the present study is a small yet first “synthetic” step to approach large and well-organized, biological capsules, composed of multiple unsymmetrical subunits, in vitro.We have challenged the perfect conversion of a complex mixture of atropisomeric MThere are no conflicts to declare.SC-011-D0SC03223A-s001SC-011-D0SC03223A-s002


The variation of tensile strengths of each phase component have the same effect on the dynamic tensile strength and energy of concrete. The dynamic tensile strength and energy of concrete are most affected by the tensile strength of mortar, following by the ITZ, but the tensile strength of aggregate has almost no effect.In mesoscopic scale, concrete is regarded as a heterogeneous three-phase material composed of mortar, aggregate and interfacial transition zone (ITZ). The effect of mesoscopic structure on the mechanical behaviors of concrete should be paid more attention. The fractal characteristics of aggregate were calculated, then the geometric models of aggregate were reconstructed by using fractal Brownian motion. Based on the random distribution of aggregates, the concrete mesoscopic structure model was established. And the numerical model was generated by using grid mapping technology. The dynamic compression experiments of concrete under Split Hopkinson Pressure Bar (SHPB) loading verify the reliability and validity of the mesoscopic structural model and the parameters of the constitutive model. Based on these, a numerical study of concrete under dynamic splitting is carried out. By changing the parameters of the constitutive model, the effects of tensile strengths of aggregate, mortar and ITZ on the dynamic tensile strength of concrete are discussed. The results show that the dynamic failure of specimen usually occurs at the interfacial transition zone, then extends to the mortar, and the aggregates rarely fail. However, the increase of strain rate intensifies this process. When the strain rate increases from 72.93 s Nowadays, many scholars have used Split Hopkinson Pressure Bar (SHPB) device to conduct experimental research on dynamic splitting of concrete, and achieved some relevant results [Concrete, as a widely used construction and building material, will be subjected to dynamic loads during its service, such as earthquakes, shocks and explosions . The res results ,12,13.With the rapid development of computing power, numerical simulation has been widely used as an important scientific method ,15,16. MIn recent years, the establishment method of three-dimensional mesoscopic structure model has gradually developed and matured. Compared with the two-dimensional model, it is closer to the real concrete and can better reflect the deformation and failure process of concrete material. Some scholars began to establish a three-dimensional structural model to study the failure mechanism of concrete at the mesoscopic level. Sadjad et al.  used theMost of the above three-dimensional concrete mesoscopic models simplify the aggregate shape into round, spherical or random convex polyhedron, which deviates from the real aggregate shape. Therefore, we have considered the heterogeneity of the mesoscopic components of concrete in this paper and regard concrete as a three-phase material composed of aggregate, mortar and ITZ. And the three-dimensional mesoscopic structure models of concrete specimens are established according to the fractal characteristics of the real aggregate shape. A SHPB system with a diameter of 120 mm was established to investigate the effect of the tensile strength of three-phase components on the dynamic splitting strengths of concrete at the mesoscopic scale.The structure of this paper is as follows: After the introduction, the establishment process of three-dimensional mesoscopic geometric model of aggregate and the generation method of ITZ are given in When concrete is simulated at the mesoscopic scale, it is very important to properly describe the geometric shape of the internal composition, that includes the shape characteristics, gradation and spatial distribution of the coarse aggregate. Jin et al.  simplifiFirstly, the geometric shape of actual concrete aggregate is calculated by using image recognition technology (gray threshold segmentation) . FractalGuinea  studied (1)r ≥ 1) like surface defined on the area R2 of the parameter Let (2)Telescopic center: (3)Stretch coefficient matrix: (4)E is the identity matrix; k is the fullness index, generally a positive integer, and 5 in the paper.Then the relationship between the curved surface The expansion factor  is definThe expansion factor is used to take the center of the aggregate section as the zoom center, and each vertex coordinate is correspondingly increased by a distance to form a new polyhedral element. The polyhedral element and the corresponding aggregate are ITZ, as showed in the It is generally accepted that the thickness of ITZ layer is relatively thin, and if the true thickness of ITZ layer is adopted, it will bring great difficulties to calculation efficiency and mesh generation. Depending on reference , the thiAfter generating the mesoscopic structure model of concrete specimens, it is necessary to transform the model into a finite element calculation model. There are various methods of finite element mesh generation, and the finite element mesh generated by gird mapping method is relatively uniform . In this(1)The initial material properties of all hexahedral elements are transformed into mortar;(2)m nodes located inside the aggregate, the material of the element is judged to be aggregate, and the value of m is set to 5;When 8 nodes of the hexahedral element have more than (3)n nodes in the remaining mortar unit belonging to the ITZ layer, it is judged that the unit belongs to the ITZ layer, and the value of n is also set to 5.When there are more than The specific implementation process of the grid mapping method is reproduced below. Firstly, commercial software Hypermesh 14.0  is used to generate a uniform hexahedron element as a background grid in the space occupied by the geometric model. Then, the mesoscale geometric model is projected onto the background, and, reutilizing the three-dimensional node information, whether the node is in the mortar, aggregate or ITZ layer can be evaluated. After judging the node attributes, it is necessary to identify the material attributes of the unit. The judging criteria and steps are as following:The schematic diagram of the grid mapping method for judging material properties is shown in 3, elastic modulus of 71 GPa and Poisson’s ratio of 0.33. The KCC (MAT_72 in LS-DYNA) [Adopting the reasonable constitutive model and parameters is very important for the effectiveness of numerical simulation. The incident bar and transmission bar are both aluminum bars, which adopt linear elastic model, with density of 2800 kg/mLS-DYNA)  model isLS-DYNA)  respectiGenerally, numerical predictions require validation of experimental results. According to the simulation results of SHPB, it is a common way to compare the reflection wave, transmission wave and the deformation and failure process of the specimen obtained by experiment and numerical calculation . In ordeIn Due to the low tensile property of concrete materials, the main failure form of concrete structures is tensile failure, and the tensile strength is an important material parameter of brittle materials. In this section, material parameters verified by rationality are mainly used to conduct numerical simulation of dynamic splitting on the mesoscopic finite element model of real aggregate established in έ(t), ε(t) and tσ(t) are the are the strain rate, strain, and stress of the specimen; A is the cross section area of the compression bar; E and C0 are the compression bar material elastic modulus and wave velocity, respectively; iε(t), rε(t), and tε(t) are the incident strain, reflected strain, and transmitted strain of a certain time t, respectively; D and L are the diameter and thickness of the specimen, respectively; and t is the duration of the stress wave.According to the literature , the mea−1, the crack initiation time and peak stress time of the sample are 990 µs and 1030 µs, respectively. When the strain rate is 186.51 s−1, the crack initiation time and peak stress time are 960 µs and 1010 µs, respectively. This shows that if the strain rate, crack time and peak stress reached moments earlier is higher, the stress of the specimen conversion rate is higher, mainly because of the higher strain rate, and the stress increases more quickly over time, which causes the crack moment to occur earlier and crack propagation to also take place ahead of time, and energy released by the propagation of the crack causes the specimen to reach peak stress at an earlier point in time. When the concrete is under the peak stress, the cracks in the concrete have not been connected, and before the cracks are connected, there are few cracks in the concrete, and there are lots of main cracks. It can be seen that the dynamic tensile strength of concrete is less affected by the number of cracks, and the number of cracks is determined by the mechanical properties after the peak stress. The crack penetration moment is greatly affected by the impact velocity, and the force of concrete at this time increases with the increase of the impact velocity. Thereafter, the excess force will lead to the development of secondary cracks of concrete and the rapid splashing of fragments.For an effective dynamic splitting test, the specimen should first fracture along the loading direction near the center of the disc. When the unshaped pulse wave is loaded, the first failure of the specimen usually occurs at the incident end after the incident wave reaches the bar/specimen interface. Soon after, the transmission end of the specimen will also be damaged. In the dynamic splitting test, the stress pulse propagates inside the disc specimen, causing tensile stress to be generated in the center of the specimen perpendicular to the direction of the loading surface, which leads to the crack initiation near the center of the concrete specimen, and the crack propagation along the loading direction. Finally, the crack coalesces and destroys the specimen . Figure −1, in the process of failure, most of the cracks in the sample bypass the aggregate and propagate through the mortar and ITZ, few cracks can propagate through the aggregate directly. Crack arrest occurs when the crack expands to the aggregate, and sufficient energy continues to be stored at the crack tip before further propagation failure, which indicates that the aggregate hinders the propagation of concrete cracks under dynamic load. However, when the strain rate increases (186.51 s−1), the energy release capacity of concrete increases, leading to the increase of energy stored at the crack tip and the increase of crack propagation directly through the aggregate. It can be seen that the propagation mode of crack is related to the energy stored at the crack tip [It can be found that at the same time, as a result of the aggregate strength and elastic modulus are higher than mortar and ITZ, when strain rate is 72.93 srack tip . When th−1 strain rate, the influence of tensile strength of each composition in concrete on macroscopic mechanical properties was studied. As a three-phase composite material composed of mortar, aggregate and ITZ, the material strength of each component is different, so the dynamic failure process of concrete is greatly influenced by each component. The three-dimensional mesoscale model can adjust the material strength of three-phase components, analyze the sensitivity of material strength of each component, study the role of each component in concrete, and further explore the methods to improve the dynamic tensile strength of concrete. The tensile strength of mortar, aggregate, and ITZ was multiplied by 2 and 0.5, respectively, that is, the tensile strength of each component increased by 100% and decreased by 50%. Under the loading condition of strain rate of a 72.93 sThe tensile stress history curves with different tensile strength of three-phase composition are plotted in The dynamic failure process of concrete is always accompanied by the variation of energy. The energy of the concrete specimen at each moment can be drawn from the numerical results. The effect of tensile strength on the energy of each component is shown in Generally speaking, the strength of the concrete structure is limited by the weakest part within it, and the weakest part should also be considered when improving the strength of a structure. Through sensitivity analysis of the tensile strength of each component, it can be seen that the ITZ has the lowest strength and is most likely to fail, which affects the energy release process of concrete and further affects its tensile strength. Mortar bypass through the entire specimen and has the largest volume ratio, which can directly affect the energy absorption capacity of concrete through its own strength. Therefore, in the dynamic test, the tensile strength of the concrete structure is primarily determined by the mortar and ITZ. In practical engineering construction, the most direct way to improve the dynamic tensile strength of concrete is to use some methods to improve the tensile strength of mortar matrix, and the high bond strength of ITZ is also an important guarantee for high tensile strength of concrete. In order to improve the dynamic tensile strength of concrete, the strength of mortar should be first considered in the preparation of concrete, and then the ITZ strength should be ensured in the preparation process. The tensile strength of aggregate has little effect on the dynamic strength of concrete, only slightly more than that of mortar.Compared with spherical and convex polygon aggregates, we have obtained the fractal characteristics of realistic aggregates by the image processing algorithm, and based on this approach, generated a 3D mesoscopic geometric model that is more consistent with the realistic aggregate. Furthermore, the grid mapping method is used to generate the numerical model. By comparing the reflection and transmission waveform and failure process of concrete dynamic compression experiment, the validity of the mesoscopic structure model of concrete is verified.−1 to 186.51 s−1, a large number of aggregate elements are deleted due to reaching the failure threshold.Based on the 3D mesoscopic model, we simulate the dynamic splitting of concrete and reproduce the rate correlation of its tensile strength, i.e., the larger the amplitude of incident wave is, the larger the amplitude of transmitted wave is. As can be seen from the dynamic failure process obtained by simulation, the failure occurs at the interfacial transition zone, then extends to the mortar, and the aggregates rarely fail. However, the increase of strain rate intensifies this process. When the strain rate increases from 72.93 sThe variation of tensile strengths of each phase component have the same effect on the dynamic tensile strength and energy of concrete. The dynamic tensile strength and energy of concrete are most affected by the tensile strength of mortar, followed by the ITZ, but the tensile strength of aggregate has almost no effect.Concrete was regarded as a three-phase material composed of aggregate, mortar and the interfacial transition zone between them. Based on the fractal characteristics of concrete aggregate, a three-dimensional mesoscopic structure model was established. The mesh mapping method was used to establish a numerical model, and the effect of strain rate on the dynamic indirect tensile strength and the progressive failure process, at the mesoscopic scale, was studied by simulating the dynamic splitting under SHPB loading. By changing the material parameters, the influence of the tensile strength of three-phase components on its dynamic indirect tensile strength is analyzed. And the main conclusions are as follows:


The materials based on concrete with an addition of rubber are well-known. The interaction between concrete components and rubber particles is in the majority cases insufficient. For this reason, different substances are introduced into concrete-rubber systems. The aim of this paper is to establish the influence of five different polymer additives, i.e., 1. an aqueous dispersion of a styrene-acrylic ester copolymer (silanised) (ASS), 2. water dispersion of styrene-acrylic copolymer (AS), 3. anionic copolymer of acrylic acid ester and styrene in the form of powder (AS.RDP), 4. water polymer dispersion produced from the vinyl acetate and ethylene monomers (EVA), 5. copolymer powder of vinyl acetate and ethylene (EVA.RDP)) on the properties of the self-leveling rubberised concrete. Scanning electron microscopy has allowed to establish the interaction between the cement paste and rubber aggregates. Moreover, the compressive strength and flexural strength of the studied materials were evaluated. The results indicate that the mechanical properties depend extensively on the type as well as the amount of the polymer additive introduced into the system. It is an enormous challenge to cause vulcanised rubber to degrade in the natural environment. For this reason, many scientists are looking for new possibilities to use that waste material. Currently, the most popular method of utilisation involves incineration or landfill disposal ,2. CurreOne of the most efficient and environmentally friendly methods of recycling waste rubber is its utilisation by incorporation into concrete and cementitious materials. Rubberised concrete is a type of clean and eco-friendly composite, which allows utilisation of rubber waste. Natural aggregates, such as sand, which are fundamental components of concrete, can be partially replaced by rubber particles varying in size , amount In recent years scientists have paid attention to cement-rubber-based materials. Since 2014 the number of reported studies has been increasing every year. Most researchers focus on the mechanical properties of rubberised concrete, such as compressive and flexural strength, which belong to the fundamental properties of concrete. According to earlier reports, the incorporation of rubber particles into the cementitious matrix reduces the mechanical properties of concrete ,13, espeIt should be mentioned that the deterioration of mechanical resistance is caused by the low stiffness of the rubber aggregates (RA) and the insufficient adhesion energy between hardened cement paste and rubber aggregates. The introduction of rubber into concrete results in a wide interfacial transition zone (ITZ) and, in effect, the rubber can easily withdraw from the matrix . The hyd2O2, CaCl2, H2SO4 and a combination treatment of KMnO4 and NaHSO4 am—the mass of the alcohol-filled pycnometer, [g]pm—the mass of the pycnometer filled with sample and alcohol, [g]ƍa—alcohol density [g/cm3]The test of solid density was carried out for hardened samples of each of the tested materials at a temperature of 23 ± 2 °C using the pycnometric method in accordance with the PN-EN 1936: 2010 standard . A sampl(b) Bulk densitym1), in water (m2), and saturated with water in the air (m3). The measurement was performed in triplicates.The test of solid density was carried out for hardened samples of each of the tested materials at a temperature of 23 ± 2 °C. The scales equipped with a density determination kit  was used for the analysis. The samples were weighed in air (mass ƍb) was calculated using the following Equation (2):m1—the mass of dried sample in air, [g]m2—the mass of sample in water, [g]m3—the mass of the water-saturated sample weighed in air, [g]ƍw—water density at 23 °C [g/cm3]The bulk density ((c) Total PorosityP [%] was calculated according to the following Equation (3):ƍb—bulk density of the sample, [g/cm3]ƍr —particle density of sample [g/cm3]Total porosity (d) Open pores volumeV [cm3] was calculated according to the following Equation (4)m2—the mass of sample in water, [g]m3—the mass of the water-saturated sample weighed in air, [g]w—water density at 23 °C [g/cm3]ƍOpen pores volume (e) Open porosityoP [%] was calculated according to the following Equation (5):m1—the mass of dried sample in air, [g]m2—the mass of sample in water, [g]m3—the mass of the water-saturated sample weighed in air, [g]Open porosity In an aim to perform three-point bending tests, three samples of the studied materials, measuring 40 mm × 40 mm × 160 mm, were formed. In order to determine the compressive strength, the samples were compressed after the flexural tests. Once moulded, the samples were allowed to cure in the mould for 24 h. During this period, the moulds were covered by a polyethylene film. The next step involved demoulding. The samples were kept in the laboratory at 20 ± 3 °C and 50 ± 5% relative humidity for subsequent 27 days. The specimens were cured under air conditions. The flexural and compressive strength tests were carried out according to PN EN 13892-2:2004, using testing machine 15/250 kN Multiserw Morek, Brzeźnica, Poland. About 50 N/s load was applied for the flexural test, and 2400 N/s load was applied for the compressive test.Workability is the crucial factor which determines the practical application of concrete. The workability of fresh state polymer-modified rubberised concrete was determined by slump flow test, one of the primary tests for self-levelling types of concrete. All samples were analysed in order to validate the workability of the designed composites. It can be clearly observed that the slump flow parameters of fresh mortar slightly increase after the addition of 1% and 5% of redispersible polymer powder additives (AS.RDP and EVA.RDP). However, an introduction of 10%wt. of redispersible polymer powders leads to the reduction in the slump parameter values compared to the control sample and the composites containing 1 and 5% wt. of AS.RDP or EVA.RDP. In literature  the reduThe addition of ASS, however, as well as AS in most cases leads to the decrease of workability of the obtained composites in comparison to the control sample. In the work of Colak  it was iSEM was employed to observe the interface between the rubber particles, the cement matrix and polymer additives. In The SEM images of the control sample consisting of water, Portland cement, calcium aluminate cement, sand, limestone and rubber aggregates are presented in Subsequently, micro-cracks seen in The micrographs of samples containing EVA in the form of latex and the redispersible powder are presented in The presence of the compound mentioned above leads to air retention in the internal voids that is confirmed by the increase in the porosity of the obtained composites. The same observations have been made by Silva et al. . The samThe addition of polymer powder and polymer dispersion into concrete leads to the formation of flexible polymer films which improve adhesion and cohesion in cementitious materials. The polymer film formation is a result of the coalescence of individual latex particles after their dehydration . HoweverFurthermore, the analysis of literature indicates that different types of polymer latexes affect the strength of the material differently . Some poDensity and porosity belong to the factors that influence the properties of concrete. Concrete characterised by higher density, in most cases, displays higher strength and reduced porosity .ƍr) and bulk density (ƍb) are shown respectively. The obtained results indicate that an introduction of different polymeric modifiers into concrete influences the density of the obtained composites. It should be stressed that grinding significantly affects the value of density, however, the change in the particle density values is consistent with the results obtained in the case of bulk density. Analyzing density we have to bear in mind that the change in density is influenced not only by the change in porosity but also by the properties of the polymer additive used in the process. For this reason total porosity (P), open pores volume (V) and open porosity (Po) were studied.Reactions during concrete formation as well as inadequate compaction result cause the resulting material to consist of both solid and a pore system . In an aP), and open porosity (oP) are shown. Based on the obtained results it has been observed that in the case samples containing anionic copolymer powder of acrylic acid ester and styrene the increase of values of total and open porosity is correlated with the reduced mechanical properties. The porosity of the ASS samples has been found to decrease with the increase in the content of the polymer additive.In The data presented in Compressive strength is the feature of a material that allows establishing the magnitude of load that can be carried on its surface without any crack or indentation. In the case of concrete, the compressive strength depends on the quality of a particular material, quality control during the production of concrete, water–cement ratio and cement strength. In an aim to obtain desired properties, the concrete based-materials are designed to display certain mechanical properties and overall durability.The obtained results are in accordance with the literature ,65,66, wThe differences in compressive strength of polymer-modified concrete between styrene-acrylic and ethylene-vinyl acetate polymers are observed. The changes can be explained by the co-matrix formation which depends on cement hydration as well as the polymer film formation.3COO− which forms during the alkaline hydrolysis of EVA in a Ca(OH)2 saturated cement pore solution, reacts with Ca2+ (originating from the dissolution of cement grains) and forms calcium acetate Ca(CH3COO)2, according to the following reaction (6) [2 content decreases. Moreover, the Hadley’s grains appear inside the matrix and the ettringite crystals are well-formed [Many researchers have studied the interaction between polymers and cement mineral phases ,69,70,71l-formed ,54.Ca influence the crystallisation of calcium hydroxide. These polymer particles adhere to the surface of formed crystals [R. Wang et al.  have shou et al.  indicateu et al.  showed tcrystals . All of Moreover, it can be clearly observed, that the compressive strength values of concrete modified by means of styrene-acrylic ester polymers in dispersion form are significantly higher than in the case of composites containing redispersible powder. This is likely to result from a different structure of the polymer. The SEA powder particles are partially covered with special additives during spray drying . It shouComparing the values of compressive strength with the total porosity and open porosity of concrete-based materials, a correlation between these parameters can be observed. Obtained results indicate a dependency between a decrease in the compressive strength of concrete and an increase in porosity of concrete. Among the samples containing 1% of polymer additives, the lowest compressive strength has been observed in the case of 1% AS.RDP material which is characterised by the highest total porosity as well as the highest open porosity. In the case of samples containing 5% of polymer additives, a similar dependency has been observed. Moreover, it should be stressed that the sample with the lowest total porosity and open porosity had the highest compressive strength. The same tendency was observed in the case of samples with 10% of polymer additives. The composites containing 10% AS and 10% AS.RDP have achieved the same level of compressive strength. In addition, the tests revealed that these were the samples with the lowest strength.It should be emphasised that the values of the total porosity for the 10% AS and 10% AS.RDP samples were the highest among the composites filled with 10% polymer additives and amounted to 30.34% and 29.83%, respectively. On the other hand, in the case of open porosity, the highest values of the discussed parameter were found in 10% AS.RDP (22.94%) and 10% EVA (19.89%) samples, while for the 10% AS material, the open porosity was only 4.01%. These observations suggest that the value of the compressive strength depends more significantly on the total porosity than on the open porosity.Flexural strength is one of the parameters which allows to establish the tensile strength of concrete. Experimental results illustrated in Differences in flexural strength of polymer-modified rubberised concrete are caused by the changes in the concrete matrix. Enhancement samples are characterised by filled pore, especially by the ettringite which, in the case of sample ASS 1%, can be clearly seen on the SEM image . MoreoveComparison of the flexural strength with the total porosity, open porosity and pore volume of the studied concrete-based materials clearly indicates that there is no correlation between these parameters. However, it should be emphasised that Jiang and Guan  reported-An aqueous dispersion of a styrene-acrylic ester copolymer (silanised);-Water dispersion of styrene-acrylic copolymer;-Anionic copolymer of acrylic acid ester and styrene in form of powder;-Water polymer dispersion produced from the monomers vinyl acetate and ethylene;-Copolymer powder of vinyl acetate and ethylene.The self-leveling rubberised concrete was modified using five different polymer additives:-Introduction of polymer additives in the form of an aqueous dispersion as well as in the form of redispersive powders into the self-leveling rubberised concrete significantly influences the microstructure of the obtained materials. However, it should be stressed that silanisation of styrene-acrylic ester copolymer dispersion allows to obtain composites characterised by the lowest values of porosity and the highest values of compressive as well as flexural strength. In the case of other studied addtives there is no simple correlation between porosity and mechanical properties of the obtained concrete-based composites.-Modification of the self-leveling rubberised concrete by means of 1% and 5% of redispersible powders increases the workability of the obtained composites, while the introduction of 10%wt. of polymeric additive leads to a reduction of studied parameter. The reduction of workability is a result of water adsorption caused by the higher amount of used redispersible powders.-The addition of 1% aqueous polymer dispersions improved the flexural strength of the studied materials, while the admixtures in the form of powder caused the value of the studied property to decrease. The additives selected for the tests reduce the flexural strength value, with a notable exception of AS, in a larger amount (5 and 10%).The effect of the additives on the microstructure and mechanical properties of concrete was determined. Based on the obtained results the following conclusions have been drawn:Overall, these findings suggest that the modification of the self-leveling rubberised concrete can be effective and the results of such modification significantly depend on the type and amount of the polymer additive used in the process.


Downsizing fossil fuel dependence and greenhouse gas emissions is at the forefront of a sustainable future. The expansion of renewable energy while striving to minimize dependence on fossil fuels has led to biomass taking the lead among renewable energy sources, with wood having the broadest application. Along with the growing trend of using biomass as a renewable energy source, the combustion of wood biomass results in wood biomass ash (WBA), leading to compelling amounts of waste. In this study, the technical feasibility of fly WBA from different Croatian power plants was analyzed to evaluate its potential use in precast concrete drainage elements and curb units. By implementing a performance-based design, the influence of various factors in thermal processing of wood biomass was investigated, together with a detailed characterization of WBA in order to assess the feasibility of using WBA as a secondary raw material in a large-scale industrial batching plant. The compressive strength and durability properties  of concrete mixtures with WBA as a replacement for 15 wt% cement were evaluated and compared with the precast concrete manufacturer’s technical requirements. The main concerns identified were compositional inconsistency of WBA, workability downturn, delay in initial reactivity rate, and increased water absorption. Concrete with WBA based on a circular design has been found to be a viable solution to cement depletion, stepping up from recycling to reuse of industrial waste. Therefore, lowering the global cement demand can be supported by using locally sourced by-products, such as wood biomass ash (WBA). By superimposing an interdisciplinary approach to identify WBA as a valuable resource for the 21st century construction industry, the problem of industrial waste, while conserving natural resources, would be solved. With increasing awareness and commitment to combat the climate crisis, more and more biomass power plants are coming on stream.Modern society is currently facing widespread, rapid, and worsening climate breakdown, while environmental degradation is having a nearly irreversible impact on people, ecosystems, and livelihoods around the world . Accordi history ,6. This missions . Moreovemissions ,11,12,13missions , in the An important step towards creating an energy system fit for a green paradigm shift is being taken by extending the overall binding target from the current 32% (set in the Renewable Energy Directive (REDII)) to a new 40% share of renewables in the EU energy mix ,16. In o2-neutral energy source because it releases almost as much CO2 during combustion as it absorbs during its growth, it is one of the most important sources of biomass for energy production in the EU, with a majority share of 59% in total renewable energy [As wood biomass is identified as a COe energy ,19,23. Ce energy , the expe energy ,29,30,31e energy ,33. As re energy , about 1e energy . In addie energy . Therefoe energy . To verie energy ,39,40,41e energy ,43,44.Even supposing that WBAs can be used effectively in cement composites, as previous research studies have reported ,39,45,46On the other hand, according to the Croatian National Environmental pollution register, WBA is classified as waste, and its free recovery in construction is currently not regulated as it is for coal fly ash. In order to be competitive with unsustainable, conventional building materials, it is essential to outline the guidelines and standards required for a wider application of WBA in the construction sector. Therefore, showcasing and promoting the health benefits of reusing WBA instead of merely landfilling has been identified as a strategy to promote a positive approach to the acceptance of unconventional materials.The aim of this study was to find the possibilities for reusing waste WBA in the production of concrete products. For this purpose, the production and testing of concrete with different WBAs in fresh and hardened states were carried out in close cooperation with a precast concrete manufacturer. The results of the tests of mixtures developed under laboratory conditions will be used for prototype production to evaluate the feasibility of using WBAs in an already established plant and to implement a full-scale commercial process, The experimental part of the research aimed to determine a suitable type of WBA that can be used as a partial cement replacement in concrete production, considering the physical properties and chemical composition of different fly WBAs, in order to gain a comprehensive insight into the effects of WBA on the mechanical and durability properties of cementitious composites. A total of 6 concrete mixes were prepared—5 concrete mixtures by replacing cement with 15 wt% WBA and 1 reference control mix, which did not contain any WBA. All concrete mixes with WBA as a replacement for the cement component were produced in the precast concrete manufacturer’s production plant. Based on the previously identified workability issues ,47, a 15The concrete specimens were prepared by mixing Portland cement CEM I 42.5 R, i.e., binder mixtures of cement and WBA, crushed stone aggregate, and potable water, complying with EN 206 . Equal pThe wood biomass fly ash used in the experiment was used as collected, without any prior treatment. A visual evaluation of the samples was performed to sort out ashes that would not be acceptable for the specific application due to impurities in the samples. However, it should be kept in mind that this kind of preliminary assessment of the WBA samples may have varied due to sampling, which is one of the major drawbacks of these materials. The visual assessment of the samples and the general characteristics of the power systems, i.e., combustion type and temperature and type of biomass used, are presented in i, where i is associated with the number of WBA sample. All concrete mixes were prepared with a maximum aggregate grain size Dmax = 16 mm. The water/binder ratio used (w/b = 0.44) was constant in all concrete mixes. The chemical admixture, a superplasticizer, was added to each mix at 0.5 mass percent of the binder, while the air entraining admixture was added at 0.1 mass percent of the binder  were prepared by replacing the cement type CEM I 42.5 R. A control mix (designated as M0) was prepared without WBA. The proposed designation for the concrete mixes was CMe binder .The physical and chemical properties of each WBA type were determined prior to the preparation of the concrete mixes, Test methods for assessing concrete properties in fresh and hardened states are listed in 2 prevailed with 44.90%. Some authors have reported that WBAs with high calcium content exhibit hydraulic properties, while the contribution of pozzolanic reaction is secondary and slow [2 content in the WBA5 sample. However, it is claimed that various parameters, such as biomass type, combustion technology, biomass combustion temperature, collection site, and storage, strongly influence the chemical compounds of WBA [2 (26.52%). The literature review also revealed a predominance of CaO, followed by SiO2 and K2O [3) ranged from 1.06% (WBA4) to 6.93% (WBA1). Only WBA3 and WBA4 with 1.84% and 1.06% met the maximum sulfate content criterion of 3.0%. The alkali content, Na2Oeq = Na2O + 0.658 K2O, given according to EN 196-2:2013 [2O5 content was less than 5.0% for all WBAs. The sum of pozzolanic oxides in the tested WBAs ranged from 21.19% (WBA2) to 58.81% (WBA5), which is less than the required 70%, indicating that the WBAs are hydraulically active or inert materials. A hydraulic balance greater than 1.4%, determined by the formula (CaO + MgO)/SiO2, also suggests possible hydraulic reactivity of WBA [The chemical composition of the WBAs and cement used in the concrete mixes were compared with the criteria for coal fly ash according to the standard EN 450-1:2013 , Table 5and slow . The WBAand slow ,61. Bases of WBA ,58,59. Cf WBA [2 .52%. The and K2O ,63. The 6-2:2013 , was fouy of WBA ,65. Accoy of WBA .50 for particle distribution are shown numerically in 3 (WBA5) to 2.67 g/cm3 (WBA1), all lower than the density of the cement used.The particle size distribution of WBA samples and cement is shown in WBAs are mainly composed of angular particles of different shapes with a non-uniform structure, which makes them morphologically different from coal fly ash, as they do not contain spherical particles . The dif3S hydration is also attributed to the incorporation of alumina and organic ions [The effect of WBA on binder hydration was studied by monitoring the heat release with isothermal calorimetry. nic ions . Moreovenic ions ,75. CompThe results of testing fresh concrete mixes in which 15 wt% of the cement was replaced by WBA and the reference mix CM0 are shown in The results obtained show that the addition of WBA can lead to a change in the consistency of the concrete mixes. When the mixture CM5 was compared with the reference mix CM0, they showed a similar consistency. Here, the concrete mixes with WBA1 and WBA4 showed a loss of workability. The loss of workability was particularly highlighted in mix CM2, where there was difficulty in molding. Previous characterizations of fly WBAs revealed irregularly shaped and highly porous particles with higher specific surface area and high carbon and free CaO content, all of which can be related to the increased water demand ,56,66. T50 in WBA2 may also be related to compressive strength drop. The compressive strength increased as the concrete aged, but none of the specimens tested achieved a higher compressive strength than the control mix. Other authors have also confirmed that the use of WBA as a cement replacement in concrete can decrease compressive strength values after 28 days [The effects of each WBA on mechanical performance of concrete were analyzed based on the demonstrated compressive strength. Thus, the differences between each WBA were reflected in the values of compressive strength of concrete with WBA, evaluated in relation to the control mix CM0 . From th 28 days ,86,87,88When analyzing the relative results of compressive strength of concrete with WBA compared to the control mix, an unfavorable effect on strength development was observed for these binary concrete mixes with WBA used as cement replacement at the level of 15 wt%, 2√h) to 96% for the CM3 mixture (1.48 kg/m2√h), 2Oeq content is common in SCMs, but a higher content, as found in the WBA2 specimens, may have a negative effect on the durability of concrete [Capillary absorption of precast concrete is not quantified in the EN 1340 standard , but speixture 1. kg/m2√h,concrete .The results of testing the water absorption of concrete specimens with WBA are shown in 2) is shown in The penetration of water under pressure was studied according to EN 12390-8:2019  to assesWhen fly ash originating from coal-fired power plants is used in concrete, the decrease in air content is mainly affected by the high LOI and alkali content, the limit of which given by the standard EN 450-1 is often exceeded in WBA concrete, as shown in 2 for the precast concrete elements, such as curbs or pavers, to fall within the exposure class XF4 for freeze–thaw risk [2 after 28 freeze–thaw cycles with de-icing salts. From the results demonstrated in 2 after 28 cycles and 3.09 kg/m2 after 56 cycles. This may be taken as an indicator that a greater amount of air entraining agent was required in this case, confirming the correlation between air instability and freeze–thaw resistance [In this study, the freeze–thaw resistance of concrete was investigated namely through scaling, i.e., surface weathering, in accordance with CEN/TS 12390-9 . The mathaw risk . In addihaw risk  limits tsistance .2) and after 56 cycles (0.30 kg/m2). For the CM3 mixture, it was not possible to determine which property of WBA had such a significant effect on the scaling of concrete.The specimen with WBA4, which had the highest LOI (24.10%) but also the highest air entrainment (6.5%), showed the least surface deterioration with a minimal mass of scaled material after 28 cycles  No. 305/2011 , the assMore extensive requirements are called for by the manufacturer in order to assess the feasibility of using WBA as a secondary raw material in a large-scale industrial batching plant. After implementing a performance-based design along with a detailed characterization of the available WBAs and their compatibility with cement, the need for a trade-off between the amount of WBA and the properties of the finished products became apparent. In order to identify a suitable product for a particular WBA, the mixture design of existing products can be adapted depending on the relevant features and the production process itself. 2 after 28 cycles of exposure to freeze–thaw attack in the presence of de-icing salts and wa≤ 6% for total water absorption). Higher values of water penetration under pressure were observed in all mixes with WBA, indicating a change in the microstructure of the concrete due to the addition of WBA. Nevertheless, the water penetration in the CM1 and CM4 mixtures was comparable to the control values. Although WBA4 had the highest LOI share (24.1%) and the lowest alkali content (3.22%), the CM4 mixture demonstrated better performance in its hardened state compared to the other mixtures. The most severe deterioration in concrete properties was observed in the CM2 mixture, which contained WBA2 with high LOI and alkali content. Therefore, this type of WBA should be subjected to pretreatment to improve its properties, such as sieving and/or washing, which would lower the alkali content and remove unburnt particles. The WBA3 sample had coarser particles compared to the cement and the other WBAs, which could have a negative effect on the durability properties. Similar findings were also obtained by [Based on the results of freeze–thaw resistance and total water absorption testing, only mixtures CM1 and CM4 met the weathering resistance requirements of EN 1340 . With respect to the examined mechanical and durability properties of concrete with WBA in the industrial environment, additional pre-treatment of some WBA would be needed in order to ensure a constant quality of the raw material. Even with satisfactory results, these figures still provide a fragmentary understanding of the new potential material in the construction industry with no recommendations for practice. Therefore, strict and regular quality control is necessary at all stages of production.